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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * linux/mm/page_alloc.c | |
4 | * | |
5 | * Manages the free list, the system allocates free pages here. | |
6 | * Note that kmalloc() lives in slab.c | |
7 | * | |
8 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
9 | * Swap reorganised 29.12.95, Stephen Tweedie | |
10 | * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 | |
11 | * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999 | |
12 | * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 | |
13 | * Zone balancing, Kanoj Sarcar, SGI, Jan 2000 | |
14 | * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002 | |
15 | * (lots of bits borrowed from Ingo Molnar & Andrew Morton) | |
16 | */ | |
17 | ||
18 | #include <linux/stddef.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/highmem.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/jiffies.h> | |
23 | #include <linux/compiler.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/kasan.h> | |
26 | #include <linux/kmsan.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/suspend.h> | |
29 | #include <linux/ratelimit.h> | |
30 | #include <linux/oom.h> | |
31 | #include <linux/topology.h> | |
32 | #include <linux/sysctl.h> | |
33 | #include <linux/cpu.h> | |
34 | #include <linux/cpuset.h> | |
35 | #include <linux/memory_hotplug.h> | |
36 | #include <linux/nodemask.h> | |
37 | #include <linux/vmstat.h> | |
38 | #include <linux/fault-inject.h> | |
39 | #include <linux/compaction.h> | |
40 | #include <trace/events/kmem.h> | |
41 | #include <trace/events/oom.h> | |
42 | #include <linux/prefetch.h> | |
43 | #include <linux/mm_inline.h> | |
44 | #include <linux/mmu_notifier.h> | |
45 | #include <linux/migrate.h> | |
46 | #include <linux/sched/mm.h> | |
47 | #include <linux/page_owner.h> | |
48 | #include <linux/page_table_check.h> | |
49 | #include <linux/memcontrol.h> | |
50 | #include <linux/ftrace.h> | |
51 | #include <linux/lockdep.h> | |
52 | #include <linux/psi.h> | |
53 | #include <linux/khugepaged.h> | |
54 | #include <linux/delayacct.h> | |
55 | #include <asm/div64.h> | |
56 | #include "internal.h" | |
57 | #include "shuffle.h" | |
58 | #include "page_reporting.h" | |
59 | ||
60 | /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */ | |
61 | typedef int __bitwise fpi_t; | |
62 | ||
63 | /* No special request */ | |
64 | #define FPI_NONE ((__force fpi_t)0) | |
65 | ||
66 | /* | |
67 | * Skip free page reporting notification for the (possibly merged) page. | |
68 | * This does not hinder free page reporting from grabbing the page, | |
69 | * reporting it and marking it "reported" - it only skips notifying | |
70 | * the free page reporting infrastructure about a newly freed page. For | |
71 | * example, used when temporarily pulling a page from a freelist and | |
72 | * putting it back unmodified. | |
73 | */ | |
74 | #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0)) | |
75 | ||
76 | /* | |
77 | * Place the (possibly merged) page to the tail of the freelist. Will ignore | |
78 | * page shuffling (relevant code - e.g., memory onlining - is expected to | |
79 | * shuffle the whole zone). | |
80 | * | |
81 | * Note: No code should rely on this flag for correctness - it's purely | |
82 | * to allow for optimizations when handing back either fresh pages | |
83 | * (memory onlining) or untouched pages (page isolation, free page | |
84 | * reporting). | |
85 | */ | |
86 | #define FPI_TO_TAIL ((__force fpi_t)BIT(1)) | |
87 | ||
88 | /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */ | |
89 | static DEFINE_MUTEX(pcp_batch_high_lock); | |
90 | #define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8) | |
91 | ||
92 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) | |
93 | /* | |
94 | * On SMP, spin_trylock is sufficient protection. | |
95 | * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP. | |
96 | */ | |
97 | #define pcp_trylock_prepare(flags) do { } while (0) | |
98 | #define pcp_trylock_finish(flag) do { } while (0) | |
99 | #else | |
100 | ||
101 | /* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */ | |
102 | #define pcp_trylock_prepare(flags) local_irq_save(flags) | |
103 | #define pcp_trylock_finish(flags) local_irq_restore(flags) | |
104 | #endif | |
105 | ||
106 | /* | |
107 | * Locking a pcp requires a PCP lookup followed by a spinlock. To avoid | |
108 | * a migration causing the wrong PCP to be locked and remote memory being | |
109 | * potentially allocated, pin the task to the CPU for the lookup+lock. | |
110 | * preempt_disable is used on !RT because it is faster than migrate_disable. | |
111 | * migrate_disable is used on RT because otherwise RT spinlock usage is | |
112 | * interfered with and a high priority task cannot preempt the allocator. | |
113 | */ | |
114 | #ifndef CONFIG_PREEMPT_RT | |
115 | #define pcpu_task_pin() preempt_disable() | |
116 | #define pcpu_task_unpin() preempt_enable() | |
117 | #else | |
118 | #define pcpu_task_pin() migrate_disable() | |
119 | #define pcpu_task_unpin() migrate_enable() | |
120 | #endif | |
121 | ||
122 | /* | |
123 | * Generic helper to lookup and a per-cpu variable with an embedded spinlock. | |
124 | * Return value should be used with equivalent unlock helper. | |
125 | */ | |
126 | #define pcpu_spin_lock(type, member, ptr) \ | |
127 | ({ \ | |
128 | type *_ret; \ | |
129 | pcpu_task_pin(); \ | |
130 | _ret = this_cpu_ptr(ptr); \ | |
131 | spin_lock(&_ret->member); \ | |
132 | _ret; \ | |
133 | }) | |
134 | ||
135 | #define pcpu_spin_trylock(type, member, ptr) \ | |
136 | ({ \ | |
137 | type *_ret; \ | |
138 | pcpu_task_pin(); \ | |
139 | _ret = this_cpu_ptr(ptr); \ | |
140 | if (!spin_trylock(&_ret->member)) { \ | |
141 | pcpu_task_unpin(); \ | |
142 | _ret = NULL; \ | |
143 | } \ | |
144 | _ret; \ | |
145 | }) | |
146 | ||
147 | #define pcpu_spin_unlock(member, ptr) \ | |
148 | ({ \ | |
149 | spin_unlock(&ptr->member); \ | |
150 | pcpu_task_unpin(); \ | |
151 | }) | |
152 | ||
153 | /* struct per_cpu_pages specific helpers. */ | |
154 | #define pcp_spin_lock(ptr) \ | |
155 | pcpu_spin_lock(struct per_cpu_pages, lock, ptr) | |
156 | ||
157 | #define pcp_spin_trylock(ptr) \ | |
158 | pcpu_spin_trylock(struct per_cpu_pages, lock, ptr) | |
159 | ||
160 | #define pcp_spin_unlock(ptr) \ | |
161 | pcpu_spin_unlock(lock, ptr) | |
162 | ||
163 | #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID | |
164 | DEFINE_PER_CPU(int, numa_node); | |
165 | EXPORT_PER_CPU_SYMBOL(numa_node); | |
166 | #endif | |
167 | ||
168 | DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key); | |
169 | ||
170 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES | |
171 | /* | |
172 | * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly. | |
173 | * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined. | |
174 | * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem() | |
175 | * defined in <linux/topology.h>. | |
176 | */ | |
177 | DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */ | |
178 | EXPORT_PER_CPU_SYMBOL(_numa_mem_); | |
179 | #endif | |
180 | ||
181 | static DEFINE_MUTEX(pcpu_drain_mutex); | |
182 | ||
183 | #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY | |
184 | volatile unsigned long latent_entropy __latent_entropy; | |
185 | EXPORT_SYMBOL(latent_entropy); | |
186 | #endif | |
187 | ||
188 | /* | |
189 | * Array of node states. | |
190 | */ | |
191 | nodemask_t node_states[NR_NODE_STATES] __read_mostly = { | |
192 | [N_POSSIBLE] = NODE_MASK_ALL, | |
193 | [N_ONLINE] = { { [0] = 1UL } }, | |
194 | #ifndef CONFIG_NUMA | |
195 | [N_NORMAL_MEMORY] = { { [0] = 1UL } }, | |
196 | #ifdef CONFIG_HIGHMEM | |
197 | [N_HIGH_MEMORY] = { { [0] = 1UL } }, | |
198 | #endif | |
199 | [N_MEMORY] = { { [0] = 1UL } }, | |
200 | [N_CPU] = { { [0] = 1UL } }, | |
201 | #endif /* NUMA */ | |
202 | }; | |
203 | EXPORT_SYMBOL(node_states); | |
204 | ||
205 | gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; | |
206 | ||
207 | /* | |
208 | * A cached value of the page's pageblock's migratetype, used when the page is | |
209 | * put on a pcplist. Used to avoid the pageblock migratetype lookup when | |
210 | * freeing from pcplists in most cases, at the cost of possibly becoming stale. | |
211 | * Also the migratetype set in the page does not necessarily match the pcplist | |
212 | * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any | |
213 | * other index - this ensures that it will be put on the correct CMA freelist. | |
214 | */ | |
215 | static inline int get_pcppage_migratetype(struct page *page) | |
216 | { | |
217 | return page->index; | |
218 | } | |
219 | ||
220 | static inline void set_pcppage_migratetype(struct page *page, int migratetype) | |
221 | { | |
222 | page->index = migratetype; | |
223 | } | |
224 | ||
225 | #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE | |
226 | unsigned int pageblock_order __read_mostly; | |
227 | #endif | |
228 | ||
229 | static void __free_pages_ok(struct page *page, unsigned int order, | |
230 | fpi_t fpi_flags); | |
231 | ||
232 | /* | |
233 | * results with 256, 32 in the lowmem_reserve sysctl: | |
234 | * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high) | |
235 | * 1G machine -> (16M dma, 784M normal, 224M high) | |
236 | * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA | |
237 | * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL | |
238 | * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA | |
239 | * | |
240 | * TBD: should special case ZONE_DMA32 machines here - in those we normally | |
241 | * don't need any ZONE_NORMAL reservation | |
242 | */ | |
243 | static int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { | |
244 | #ifdef CONFIG_ZONE_DMA | |
245 | [ZONE_DMA] = 256, | |
246 | #endif | |
247 | #ifdef CONFIG_ZONE_DMA32 | |
248 | [ZONE_DMA32] = 256, | |
249 | #endif | |
250 | [ZONE_NORMAL] = 32, | |
251 | #ifdef CONFIG_HIGHMEM | |
252 | [ZONE_HIGHMEM] = 0, | |
253 | #endif | |
254 | [ZONE_MOVABLE] = 0, | |
255 | }; | |
256 | ||
257 | char * const zone_names[MAX_NR_ZONES] = { | |
258 | #ifdef CONFIG_ZONE_DMA | |
259 | "DMA", | |
260 | #endif | |
261 | #ifdef CONFIG_ZONE_DMA32 | |
262 | "DMA32", | |
263 | #endif | |
264 | "Normal", | |
265 | #ifdef CONFIG_HIGHMEM | |
266 | "HighMem", | |
267 | #endif | |
268 | "Movable", | |
269 | #ifdef CONFIG_ZONE_DEVICE | |
270 | "Device", | |
271 | #endif | |
272 | }; | |
273 | ||
274 | const char * const migratetype_names[MIGRATE_TYPES] = { | |
275 | "Unmovable", | |
276 | "Movable", | |
277 | "Reclaimable", | |
278 | "HighAtomic", | |
279 | #ifdef CONFIG_CMA | |
280 | "CMA", | |
281 | #endif | |
282 | #ifdef CONFIG_MEMORY_ISOLATION | |
283 | "Isolate", | |
284 | #endif | |
285 | }; | |
286 | ||
287 | int min_free_kbytes = 1024; | |
288 | int user_min_free_kbytes = -1; | |
289 | static int watermark_boost_factor __read_mostly = 15000; | |
290 | static int watermark_scale_factor = 10; | |
291 | ||
292 | /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */ | |
293 | int movable_zone; | |
294 | EXPORT_SYMBOL(movable_zone); | |
295 | ||
296 | #if MAX_NUMNODES > 1 | |
297 | unsigned int nr_node_ids __read_mostly = MAX_NUMNODES; | |
298 | unsigned int nr_online_nodes __read_mostly = 1; | |
299 | EXPORT_SYMBOL(nr_node_ids); | |
300 | EXPORT_SYMBOL(nr_online_nodes); | |
301 | #endif | |
302 | ||
303 | static bool page_contains_unaccepted(struct page *page, unsigned int order); | |
304 | static void accept_page(struct page *page, unsigned int order); | |
305 | static bool try_to_accept_memory(struct zone *zone, unsigned int order); | |
306 | static inline bool has_unaccepted_memory(void); | |
307 | static bool __free_unaccepted(struct page *page); | |
308 | ||
309 | int page_group_by_mobility_disabled __read_mostly; | |
310 | ||
311 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT | |
312 | /* | |
313 | * During boot we initialize deferred pages on-demand, as needed, but once | |
314 | * page_alloc_init_late() has finished, the deferred pages are all initialized, | |
315 | * and we can permanently disable that path. | |
316 | */ | |
317 | DEFINE_STATIC_KEY_TRUE(deferred_pages); | |
318 | ||
319 | static inline bool deferred_pages_enabled(void) | |
320 | { | |
321 | return static_branch_unlikely(&deferred_pages); | |
322 | } | |
323 | ||
324 | /* | |
325 | * deferred_grow_zone() is __init, but it is called from | |
326 | * get_page_from_freelist() during early boot until deferred_pages permanently | |
327 | * disables this call. This is why we have refdata wrapper to avoid warning, | |
328 | * and to ensure that the function body gets unloaded. | |
329 | */ | |
330 | static bool __ref | |
331 | _deferred_grow_zone(struct zone *zone, unsigned int order) | |
332 | { | |
333 | return deferred_grow_zone(zone, order); | |
334 | } | |
335 | #else | |
336 | static inline bool deferred_pages_enabled(void) | |
337 | { | |
338 | return false; | |
339 | } | |
340 | #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ | |
341 | ||
342 | /* Return a pointer to the bitmap storing bits affecting a block of pages */ | |
343 | static inline unsigned long *get_pageblock_bitmap(const struct page *page, | |
344 | unsigned long pfn) | |
345 | { | |
346 | #ifdef CONFIG_SPARSEMEM | |
347 | return section_to_usemap(__pfn_to_section(pfn)); | |
348 | #else | |
349 | return page_zone(page)->pageblock_flags; | |
350 | #endif /* CONFIG_SPARSEMEM */ | |
351 | } | |
352 | ||
353 | static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn) | |
354 | { | |
355 | #ifdef CONFIG_SPARSEMEM | |
356 | pfn &= (PAGES_PER_SECTION-1); | |
357 | #else | |
358 | pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn); | |
359 | #endif /* CONFIG_SPARSEMEM */ | |
360 | return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; | |
361 | } | |
362 | ||
363 | /** | |
364 | * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages | |
365 | * @page: The page within the block of interest | |
366 | * @pfn: The target page frame number | |
367 | * @mask: mask of bits that the caller is interested in | |
368 | * | |
369 | * Return: pageblock_bits flags | |
370 | */ | |
371 | unsigned long get_pfnblock_flags_mask(const struct page *page, | |
372 | unsigned long pfn, unsigned long mask) | |
373 | { | |
374 | unsigned long *bitmap; | |
375 | unsigned long bitidx, word_bitidx; | |
376 | unsigned long word; | |
377 | ||
378 | bitmap = get_pageblock_bitmap(page, pfn); | |
379 | bitidx = pfn_to_bitidx(page, pfn); | |
380 | word_bitidx = bitidx / BITS_PER_LONG; | |
381 | bitidx &= (BITS_PER_LONG-1); | |
382 | /* | |
383 | * This races, without locks, with set_pfnblock_flags_mask(). Ensure | |
384 | * a consistent read of the memory array, so that results, even though | |
385 | * racy, are not corrupted. | |
386 | */ | |
387 | word = READ_ONCE(bitmap[word_bitidx]); | |
388 | return (word >> bitidx) & mask; | |
389 | } | |
390 | ||
391 | static __always_inline int get_pfnblock_migratetype(const struct page *page, | |
392 | unsigned long pfn) | |
393 | { | |
394 | return get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK); | |
395 | } | |
396 | ||
397 | /** | |
398 | * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages | |
399 | * @page: The page within the block of interest | |
400 | * @flags: The flags to set | |
401 | * @pfn: The target page frame number | |
402 | * @mask: mask of bits that the caller is interested in | |
403 | */ | |
404 | void set_pfnblock_flags_mask(struct page *page, unsigned long flags, | |
405 | unsigned long pfn, | |
406 | unsigned long mask) | |
407 | { | |
408 | unsigned long *bitmap; | |
409 | unsigned long bitidx, word_bitidx; | |
410 | unsigned long word; | |
411 | ||
412 | BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4); | |
413 | BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits)); | |
414 | ||
415 | bitmap = get_pageblock_bitmap(page, pfn); | |
416 | bitidx = pfn_to_bitidx(page, pfn); | |
417 | word_bitidx = bitidx / BITS_PER_LONG; | |
418 | bitidx &= (BITS_PER_LONG-1); | |
419 | ||
420 | VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); | |
421 | ||
422 | mask <<= bitidx; | |
423 | flags <<= bitidx; | |
424 | ||
425 | word = READ_ONCE(bitmap[word_bitidx]); | |
426 | do { | |
427 | } while (!try_cmpxchg(&bitmap[word_bitidx], &word, (word & ~mask) | flags)); | |
428 | } | |
429 | ||
430 | void set_pageblock_migratetype(struct page *page, int migratetype) | |
431 | { | |
432 | if (unlikely(page_group_by_mobility_disabled && | |
433 | migratetype < MIGRATE_PCPTYPES)) | |
434 | migratetype = MIGRATE_UNMOVABLE; | |
435 | ||
436 | set_pfnblock_flags_mask(page, (unsigned long)migratetype, | |
437 | page_to_pfn(page), MIGRATETYPE_MASK); | |
438 | } | |
439 | ||
440 | #ifdef CONFIG_DEBUG_VM | |
441 | static int page_outside_zone_boundaries(struct zone *zone, struct page *page) | |
442 | { | |
443 | int ret; | |
444 | unsigned seq; | |
445 | unsigned long pfn = page_to_pfn(page); | |
446 | unsigned long sp, start_pfn; | |
447 | ||
448 | do { | |
449 | seq = zone_span_seqbegin(zone); | |
450 | start_pfn = zone->zone_start_pfn; | |
451 | sp = zone->spanned_pages; | |
452 | ret = !zone_spans_pfn(zone, pfn); | |
453 | } while (zone_span_seqretry(zone, seq)); | |
454 | ||
455 | if (ret) | |
456 | pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n", | |
457 | pfn, zone_to_nid(zone), zone->name, | |
458 | start_pfn, start_pfn + sp); | |
459 | ||
460 | return ret; | |
461 | } | |
462 | ||
463 | /* | |
464 | * Temporary debugging check for pages not lying within a given zone. | |
465 | */ | |
466 | static int __maybe_unused bad_range(struct zone *zone, struct page *page) | |
467 | { | |
468 | if (page_outside_zone_boundaries(zone, page)) | |
469 | return 1; | |
470 | if (zone != page_zone(page)) | |
471 | return 1; | |
472 | ||
473 | return 0; | |
474 | } | |
475 | #else | |
476 | static inline int __maybe_unused bad_range(struct zone *zone, struct page *page) | |
477 | { | |
478 | return 0; | |
479 | } | |
480 | #endif | |
481 | ||
482 | static void bad_page(struct page *page, const char *reason) | |
483 | { | |
484 | static unsigned long resume; | |
485 | static unsigned long nr_shown; | |
486 | static unsigned long nr_unshown; | |
487 | ||
488 | /* | |
489 | * Allow a burst of 60 reports, then keep quiet for that minute; | |
490 | * or allow a steady drip of one report per second. | |
491 | */ | |
492 | if (nr_shown == 60) { | |
493 | if (time_before(jiffies, resume)) { | |
494 | nr_unshown++; | |
495 | goto out; | |
496 | } | |
497 | if (nr_unshown) { | |
498 | pr_alert( | |
499 | "BUG: Bad page state: %lu messages suppressed\n", | |
500 | nr_unshown); | |
501 | nr_unshown = 0; | |
502 | } | |
503 | nr_shown = 0; | |
504 | } | |
505 | if (nr_shown++ == 0) | |
506 | resume = jiffies + 60 * HZ; | |
507 | ||
508 | pr_alert("BUG: Bad page state in process %s pfn:%05lx\n", | |
509 | current->comm, page_to_pfn(page)); | |
510 | dump_page(page, reason); | |
511 | ||
512 | print_modules(); | |
513 | dump_stack(); | |
514 | out: | |
515 | /* Leave bad fields for debug, except PageBuddy could make trouble */ | |
516 | page_mapcount_reset(page); /* remove PageBuddy */ | |
517 | add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); | |
518 | } | |
519 | ||
520 | static inline unsigned int order_to_pindex(int migratetype, int order) | |
521 | { | |
522 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
523 | if (order > PAGE_ALLOC_COSTLY_ORDER) { | |
524 | VM_BUG_ON(order != pageblock_order); | |
525 | return NR_LOWORDER_PCP_LISTS; | |
526 | } | |
527 | #else | |
528 | VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); | |
529 | #endif | |
530 | ||
531 | return (MIGRATE_PCPTYPES * order) + migratetype; | |
532 | } | |
533 | ||
534 | static inline int pindex_to_order(unsigned int pindex) | |
535 | { | |
536 | int order = pindex / MIGRATE_PCPTYPES; | |
537 | ||
538 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
539 | if (pindex == NR_LOWORDER_PCP_LISTS) | |
540 | order = pageblock_order; | |
541 | #else | |
542 | VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); | |
543 | #endif | |
544 | ||
545 | return order; | |
546 | } | |
547 | ||
548 | static inline bool pcp_allowed_order(unsigned int order) | |
549 | { | |
550 | if (order <= PAGE_ALLOC_COSTLY_ORDER) | |
551 | return true; | |
552 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
553 | if (order == pageblock_order) | |
554 | return true; | |
555 | #endif | |
556 | return false; | |
557 | } | |
558 | ||
559 | static inline void free_the_page(struct page *page, unsigned int order) | |
560 | { | |
561 | if (pcp_allowed_order(order)) /* Via pcp? */ | |
562 | free_unref_page(page, order); | |
563 | else | |
564 | __free_pages_ok(page, order, FPI_NONE); | |
565 | } | |
566 | ||
567 | /* | |
568 | * Higher-order pages are called "compound pages". They are structured thusly: | |
569 | * | |
570 | * The first PAGE_SIZE page is called the "head page" and have PG_head set. | |
571 | * | |
572 | * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded | |
573 | * in bit 0 of page->compound_head. The rest of bits is pointer to head page. | |
574 | * | |
575 | * The first tail page's ->compound_order holds the order of allocation. | |
576 | * This usage means that zero-order pages may not be compound. | |
577 | */ | |
578 | ||
579 | void prep_compound_page(struct page *page, unsigned int order) | |
580 | { | |
581 | int i; | |
582 | int nr_pages = 1 << order; | |
583 | ||
584 | __SetPageHead(page); | |
585 | for (i = 1; i < nr_pages; i++) | |
586 | prep_compound_tail(page, i); | |
587 | ||
588 | prep_compound_head(page, order); | |
589 | } | |
590 | ||
591 | void destroy_large_folio(struct folio *folio) | |
592 | { | |
593 | if (folio_test_hugetlb(folio)) { | |
594 | free_huge_folio(folio); | |
595 | return; | |
596 | } | |
597 | ||
598 | if (folio_test_large_rmappable(folio)) | |
599 | folio_undo_large_rmappable(folio); | |
600 | ||
601 | mem_cgroup_uncharge(folio); | |
602 | free_the_page(&folio->page, folio_order(folio)); | |
603 | } | |
604 | ||
605 | static inline void set_buddy_order(struct page *page, unsigned int order) | |
606 | { | |
607 | set_page_private(page, order); | |
608 | __SetPageBuddy(page); | |
609 | } | |
610 | ||
611 | #ifdef CONFIG_COMPACTION | |
612 | static inline struct capture_control *task_capc(struct zone *zone) | |
613 | { | |
614 | struct capture_control *capc = current->capture_control; | |
615 | ||
616 | return unlikely(capc) && | |
617 | !(current->flags & PF_KTHREAD) && | |
618 | !capc->page && | |
619 | capc->cc->zone == zone ? capc : NULL; | |
620 | } | |
621 | ||
622 | static inline bool | |
623 | compaction_capture(struct capture_control *capc, struct page *page, | |
624 | int order, int migratetype) | |
625 | { | |
626 | if (!capc || order != capc->cc->order) | |
627 | return false; | |
628 | ||
629 | /* Do not accidentally pollute CMA or isolated regions*/ | |
630 | if (is_migrate_cma(migratetype) || | |
631 | is_migrate_isolate(migratetype)) | |
632 | return false; | |
633 | ||
634 | /* | |
635 | * Do not let lower order allocations pollute a movable pageblock. | |
636 | * This might let an unmovable request use a reclaimable pageblock | |
637 | * and vice-versa but no more than normal fallback logic which can | |
638 | * have trouble finding a high-order free page. | |
639 | */ | |
640 | if (order < pageblock_order && migratetype == MIGRATE_MOVABLE) | |
641 | return false; | |
642 | ||
643 | capc->page = page; | |
644 | return true; | |
645 | } | |
646 | ||
647 | #else | |
648 | static inline struct capture_control *task_capc(struct zone *zone) | |
649 | { | |
650 | return NULL; | |
651 | } | |
652 | ||
653 | static inline bool | |
654 | compaction_capture(struct capture_control *capc, struct page *page, | |
655 | int order, int migratetype) | |
656 | { | |
657 | return false; | |
658 | } | |
659 | #endif /* CONFIG_COMPACTION */ | |
660 | ||
661 | /* Used for pages not on another list */ | |
662 | static inline void add_to_free_list(struct page *page, struct zone *zone, | |
663 | unsigned int order, int migratetype) | |
664 | { | |
665 | struct free_area *area = &zone->free_area[order]; | |
666 | ||
667 | list_add(&page->buddy_list, &area->free_list[migratetype]); | |
668 | area->nr_free++; | |
669 | } | |
670 | ||
671 | /* Used for pages not on another list */ | |
672 | static inline void add_to_free_list_tail(struct page *page, struct zone *zone, | |
673 | unsigned int order, int migratetype) | |
674 | { | |
675 | struct free_area *area = &zone->free_area[order]; | |
676 | ||
677 | list_add_tail(&page->buddy_list, &area->free_list[migratetype]); | |
678 | area->nr_free++; | |
679 | } | |
680 | ||
681 | /* | |
682 | * Used for pages which are on another list. Move the pages to the tail | |
683 | * of the list - so the moved pages won't immediately be considered for | |
684 | * allocation again (e.g., optimization for memory onlining). | |
685 | */ | |
686 | static inline void move_to_free_list(struct page *page, struct zone *zone, | |
687 | unsigned int order, int migratetype) | |
688 | { | |
689 | struct free_area *area = &zone->free_area[order]; | |
690 | ||
691 | list_move_tail(&page->buddy_list, &area->free_list[migratetype]); | |
692 | } | |
693 | ||
694 | static inline void del_page_from_free_list(struct page *page, struct zone *zone, | |
695 | unsigned int order) | |
696 | { | |
697 | /* clear reported state and update reported page count */ | |
698 | if (page_reported(page)) | |
699 | __ClearPageReported(page); | |
700 | ||
701 | list_del(&page->buddy_list); | |
702 | __ClearPageBuddy(page); | |
703 | set_page_private(page, 0); | |
704 | zone->free_area[order].nr_free--; | |
705 | } | |
706 | ||
707 | static inline struct page *get_page_from_free_area(struct free_area *area, | |
708 | int migratetype) | |
709 | { | |
710 | return list_first_entry_or_null(&area->free_list[migratetype], | |
711 | struct page, buddy_list); | |
712 | } | |
713 | ||
714 | /* | |
715 | * If this is not the largest possible page, check if the buddy | |
716 | * of the next-highest order is free. If it is, it's possible | |
717 | * that pages are being freed that will coalesce soon. In case, | |
718 | * that is happening, add the free page to the tail of the list | |
719 | * so it's less likely to be used soon and more likely to be merged | |
720 | * as a higher order page | |
721 | */ | |
722 | static inline bool | |
723 | buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, | |
724 | struct page *page, unsigned int order) | |
725 | { | |
726 | unsigned long higher_page_pfn; | |
727 | struct page *higher_page; | |
728 | ||
729 | if (order >= MAX_ORDER - 1) | |
730 | return false; | |
731 | ||
732 | higher_page_pfn = buddy_pfn & pfn; | |
733 | higher_page = page + (higher_page_pfn - pfn); | |
734 | ||
735 | return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1, | |
736 | NULL) != NULL; | |
737 | } | |
738 | ||
739 | /* | |
740 | * Freeing function for a buddy system allocator. | |
741 | * | |
742 | * The concept of a buddy system is to maintain direct-mapped table | |
743 | * (containing bit values) for memory blocks of various "orders". | |
744 | * The bottom level table contains the map for the smallest allocatable | |
745 | * units of memory (here, pages), and each level above it describes | |
746 | * pairs of units from the levels below, hence, "buddies". | |
747 | * At a high level, all that happens here is marking the table entry | |
748 | * at the bottom level available, and propagating the changes upward | |
749 | * as necessary, plus some accounting needed to play nicely with other | |
750 | * parts of the VM system. | |
751 | * At each level, we keep a list of pages, which are heads of continuous | |
752 | * free pages of length of (1 << order) and marked with PageBuddy. | |
753 | * Page's order is recorded in page_private(page) field. | |
754 | * So when we are allocating or freeing one, we can derive the state of the | |
755 | * other. That is, if we allocate a small block, and both were | |
756 | * free, the remainder of the region must be split into blocks. | |
757 | * If a block is freed, and its buddy is also free, then this | |
758 | * triggers coalescing into a block of larger size. | |
759 | * | |
760 | * -- nyc | |
761 | */ | |
762 | ||
763 | static inline void __free_one_page(struct page *page, | |
764 | unsigned long pfn, | |
765 | struct zone *zone, unsigned int order, | |
766 | int migratetype, fpi_t fpi_flags) | |
767 | { | |
768 | struct capture_control *capc = task_capc(zone); | |
769 | unsigned long buddy_pfn = 0; | |
770 | unsigned long combined_pfn; | |
771 | struct page *buddy; | |
772 | bool to_tail; | |
773 | ||
774 | VM_BUG_ON(!zone_is_initialized(zone)); | |
775 | VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); | |
776 | ||
777 | VM_BUG_ON(migratetype == -1); | |
778 | if (likely(!is_migrate_isolate(migratetype))) | |
779 | __mod_zone_freepage_state(zone, 1 << order, migratetype); | |
780 | ||
781 | VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page); | |
782 | VM_BUG_ON_PAGE(bad_range(zone, page), page); | |
783 | ||
784 | while (order < MAX_ORDER) { | |
785 | if (compaction_capture(capc, page, order, migratetype)) { | |
786 | __mod_zone_freepage_state(zone, -(1 << order), | |
787 | migratetype); | |
788 | return; | |
789 | } | |
790 | ||
791 | buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn); | |
792 | if (!buddy) | |
793 | goto done_merging; | |
794 | ||
795 | if (unlikely(order >= pageblock_order)) { | |
796 | /* | |
797 | * We want to prevent merge between freepages on pageblock | |
798 | * without fallbacks and normal pageblock. Without this, | |
799 | * pageblock isolation could cause incorrect freepage or CMA | |
800 | * accounting or HIGHATOMIC accounting. | |
801 | */ | |
802 | int buddy_mt = get_pfnblock_migratetype(buddy, buddy_pfn); | |
803 | ||
804 | if (migratetype != buddy_mt | |
805 | && (!migratetype_is_mergeable(migratetype) || | |
806 | !migratetype_is_mergeable(buddy_mt))) | |
807 | goto done_merging; | |
808 | } | |
809 | ||
810 | /* | |
811 | * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, | |
812 | * merge with it and move up one order. | |
813 | */ | |
814 | if (page_is_guard(buddy)) | |
815 | clear_page_guard(zone, buddy, order, migratetype); | |
816 | else | |
817 | del_page_from_free_list(buddy, zone, order); | |
818 | combined_pfn = buddy_pfn & pfn; | |
819 | page = page + (combined_pfn - pfn); | |
820 | pfn = combined_pfn; | |
821 | order++; | |
822 | } | |
823 | ||
824 | done_merging: | |
825 | set_buddy_order(page, order); | |
826 | ||
827 | if (fpi_flags & FPI_TO_TAIL) | |
828 | to_tail = true; | |
829 | else if (is_shuffle_order(order)) | |
830 | to_tail = shuffle_pick_tail(); | |
831 | else | |
832 | to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order); | |
833 | ||
834 | if (to_tail) | |
835 | add_to_free_list_tail(page, zone, order, migratetype); | |
836 | else | |
837 | add_to_free_list(page, zone, order, migratetype); | |
838 | ||
839 | /* Notify page reporting subsystem of freed page */ | |
840 | if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY)) | |
841 | page_reporting_notify_free(order); | |
842 | } | |
843 | ||
844 | /** | |
845 | * split_free_page() -- split a free page at split_pfn_offset | |
846 | * @free_page: the original free page | |
847 | * @order: the order of the page | |
848 | * @split_pfn_offset: split offset within the page | |
849 | * | |
850 | * Return -ENOENT if the free page is changed, otherwise 0 | |
851 | * | |
852 | * It is used when the free page crosses two pageblocks with different migratetypes | |
853 | * at split_pfn_offset within the page. The split free page will be put into | |
854 | * separate migratetype lists afterwards. Otherwise, the function achieves | |
855 | * nothing. | |
856 | */ | |
857 | int split_free_page(struct page *free_page, | |
858 | unsigned int order, unsigned long split_pfn_offset) | |
859 | { | |
860 | struct zone *zone = page_zone(free_page); | |
861 | unsigned long free_page_pfn = page_to_pfn(free_page); | |
862 | unsigned long pfn; | |
863 | unsigned long flags; | |
864 | int free_page_order; | |
865 | int mt; | |
866 | int ret = 0; | |
867 | ||
868 | if (split_pfn_offset == 0) | |
869 | return ret; | |
870 | ||
871 | spin_lock_irqsave(&zone->lock, flags); | |
872 | ||
873 | if (!PageBuddy(free_page) || buddy_order(free_page) != order) { | |
874 | ret = -ENOENT; | |
875 | goto out; | |
876 | } | |
877 | ||
878 | mt = get_pfnblock_migratetype(free_page, free_page_pfn); | |
879 | if (likely(!is_migrate_isolate(mt))) | |
880 | __mod_zone_freepage_state(zone, -(1UL << order), mt); | |
881 | ||
882 | del_page_from_free_list(free_page, zone, order); | |
883 | for (pfn = free_page_pfn; | |
884 | pfn < free_page_pfn + (1UL << order);) { | |
885 | int mt = get_pfnblock_migratetype(pfn_to_page(pfn), pfn); | |
886 | ||
887 | free_page_order = min_t(unsigned int, | |
888 | pfn ? __ffs(pfn) : order, | |
889 | __fls(split_pfn_offset)); | |
890 | __free_one_page(pfn_to_page(pfn), pfn, zone, free_page_order, | |
891 | mt, FPI_NONE); | |
892 | pfn += 1UL << free_page_order; | |
893 | split_pfn_offset -= (1UL << free_page_order); | |
894 | /* we have done the first part, now switch to second part */ | |
895 | if (split_pfn_offset == 0) | |
896 | split_pfn_offset = (1UL << order) - (pfn - free_page_pfn); | |
897 | } | |
898 | out: | |
899 | spin_unlock_irqrestore(&zone->lock, flags); | |
900 | return ret; | |
901 | } | |
902 | /* | |
903 | * A bad page could be due to a number of fields. Instead of multiple branches, | |
904 | * try and check multiple fields with one check. The caller must do a detailed | |
905 | * check if necessary. | |
906 | */ | |
907 | static inline bool page_expected_state(struct page *page, | |
908 | unsigned long check_flags) | |
909 | { | |
910 | if (unlikely(atomic_read(&page->_mapcount) != -1)) | |
911 | return false; | |
912 | ||
913 | if (unlikely((unsigned long)page->mapping | | |
914 | page_ref_count(page) | | |
915 | #ifdef CONFIG_MEMCG | |
916 | page->memcg_data | | |
917 | #endif | |
918 | (page->flags & check_flags))) | |
919 | return false; | |
920 | ||
921 | return true; | |
922 | } | |
923 | ||
924 | static const char *page_bad_reason(struct page *page, unsigned long flags) | |
925 | { | |
926 | const char *bad_reason = NULL; | |
927 | ||
928 | if (unlikely(atomic_read(&page->_mapcount) != -1)) | |
929 | bad_reason = "nonzero mapcount"; | |
930 | if (unlikely(page->mapping != NULL)) | |
931 | bad_reason = "non-NULL mapping"; | |
932 | if (unlikely(page_ref_count(page) != 0)) | |
933 | bad_reason = "nonzero _refcount"; | |
934 | if (unlikely(page->flags & flags)) { | |
935 | if (flags == PAGE_FLAGS_CHECK_AT_PREP) | |
936 | bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set"; | |
937 | else | |
938 | bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; | |
939 | } | |
940 | #ifdef CONFIG_MEMCG | |
941 | if (unlikely(page->memcg_data)) | |
942 | bad_reason = "page still charged to cgroup"; | |
943 | #endif | |
944 | return bad_reason; | |
945 | } | |
946 | ||
947 | static void free_page_is_bad_report(struct page *page) | |
948 | { | |
949 | bad_page(page, | |
950 | page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE)); | |
951 | } | |
952 | ||
953 | static inline bool free_page_is_bad(struct page *page) | |
954 | { | |
955 | if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) | |
956 | return false; | |
957 | ||
958 | /* Something has gone sideways, find it */ | |
959 | free_page_is_bad_report(page); | |
960 | return true; | |
961 | } | |
962 | ||
963 | static inline bool is_check_pages_enabled(void) | |
964 | { | |
965 | return static_branch_unlikely(&check_pages_enabled); | |
966 | } | |
967 | ||
968 | static int free_tail_page_prepare(struct page *head_page, struct page *page) | |
969 | { | |
970 | struct folio *folio = (struct folio *)head_page; | |
971 | int ret = 1; | |
972 | ||
973 | /* | |
974 | * We rely page->lru.next never has bit 0 set, unless the page | |
975 | * is PageTail(). Let's make sure that's true even for poisoned ->lru. | |
976 | */ | |
977 | BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1); | |
978 | ||
979 | if (!is_check_pages_enabled()) { | |
980 | ret = 0; | |
981 | goto out; | |
982 | } | |
983 | switch (page - head_page) { | |
984 | case 1: | |
985 | /* the first tail page: these may be in place of ->mapping */ | |
986 | if (unlikely(folio_entire_mapcount(folio))) { | |
987 | bad_page(page, "nonzero entire_mapcount"); | |
988 | goto out; | |
989 | } | |
990 | if (unlikely(atomic_read(&folio->_nr_pages_mapped))) { | |
991 | bad_page(page, "nonzero nr_pages_mapped"); | |
992 | goto out; | |
993 | } | |
994 | if (unlikely(atomic_read(&folio->_pincount))) { | |
995 | bad_page(page, "nonzero pincount"); | |
996 | goto out; | |
997 | } | |
998 | break; | |
999 | case 2: | |
1000 | /* | |
1001 | * the second tail page: ->mapping is | |
1002 | * deferred_list.next -- ignore value. | |
1003 | */ | |
1004 | break; | |
1005 | default: | |
1006 | if (page->mapping != TAIL_MAPPING) { | |
1007 | bad_page(page, "corrupted mapping in tail page"); | |
1008 | goto out; | |
1009 | } | |
1010 | break; | |
1011 | } | |
1012 | if (unlikely(!PageTail(page))) { | |
1013 | bad_page(page, "PageTail not set"); | |
1014 | goto out; | |
1015 | } | |
1016 | if (unlikely(compound_head(page) != head_page)) { | |
1017 | bad_page(page, "compound_head not consistent"); | |
1018 | goto out; | |
1019 | } | |
1020 | ret = 0; | |
1021 | out: | |
1022 | page->mapping = NULL; | |
1023 | clear_compound_head(page); | |
1024 | return ret; | |
1025 | } | |
1026 | ||
1027 | /* | |
1028 | * Skip KASAN memory poisoning when either: | |
1029 | * | |
1030 | * 1. For generic KASAN: deferred memory initialization has not yet completed. | |
1031 | * Tag-based KASAN modes skip pages freed via deferred memory initialization | |
1032 | * using page tags instead (see below). | |
1033 | * 2. For tag-based KASAN modes: the page has a match-all KASAN tag, indicating | |
1034 | * that error detection is disabled for accesses via the page address. | |
1035 | * | |
1036 | * Pages will have match-all tags in the following circumstances: | |
1037 | * | |
1038 | * 1. Pages are being initialized for the first time, including during deferred | |
1039 | * memory init; see the call to page_kasan_tag_reset in __init_single_page. | |
1040 | * 2. The allocation was not unpoisoned due to __GFP_SKIP_KASAN, with the | |
1041 | * exception of pages unpoisoned by kasan_unpoison_vmalloc. | |
1042 | * 3. The allocation was excluded from being checked due to sampling, | |
1043 | * see the call to kasan_unpoison_pages. | |
1044 | * | |
1045 | * Poisoning pages during deferred memory init will greatly lengthen the | |
1046 | * process and cause problem in large memory systems as the deferred pages | |
1047 | * initialization is done with interrupt disabled. | |
1048 | * | |
1049 | * Assuming that there will be no reference to those newly initialized | |
1050 | * pages before they are ever allocated, this should have no effect on | |
1051 | * KASAN memory tracking as the poison will be properly inserted at page | |
1052 | * allocation time. The only corner case is when pages are allocated by | |
1053 | * on-demand allocation and then freed again before the deferred pages | |
1054 | * initialization is done, but this is not likely to happen. | |
1055 | */ | |
1056 | static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) | |
1057 | { | |
1058 | if (IS_ENABLED(CONFIG_KASAN_GENERIC)) | |
1059 | return deferred_pages_enabled(); | |
1060 | ||
1061 | return page_kasan_tag(page) == 0xff; | |
1062 | } | |
1063 | ||
1064 | static void kernel_init_pages(struct page *page, int numpages) | |
1065 | { | |
1066 | int i; | |
1067 | ||
1068 | /* s390's use of memset() could override KASAN redzones. */ | |
1069 | kasan_disable_current(); | |
1070 | for (i = 0; i < numpages; i++) | |
1071 | clear_highpage_kasan_tagged(page + i); | |
1072 | kasan_enable_current(); | |
1073 | } | |
1074 | ||
1075 | static __always_inline bool free_pages_prepare(struct page *page, | |
1076 | unsigned int order, fpi_t fpi_flags) | |
1077 | { | |
1078 | int bad = 0; | |
1079 | bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags); | |
1080 | bool init = want_init_on_free(); | |
1081 | ||
1082 | VM_BUG_ON_PAGE(PageTail(page), page); | |
1083 | ||
1084 | trace_mm_page_free(page, order); | |
1085 | kmsan_free_page(page, order); | |
1086 | ||
1087 | if (unlikely(PageHWPoison(page)) && !order) { | |
1088 | /* | |
1089 | * Do not let hwpoison pages hit pcplists/buddy | |
1090 | * Untie memcg state and reset page's owner | |
1091 | */ | |
1092 | if (memcg_kmem_online() && PageMemcgKmem(page)) | |
1093 | __memcg_kmem_uncharge_page(page, order); | |
1094 | reset_page_owner(page, order); | |
1095 | page_table_check_free(page, order); | |
1096 | return false; | |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * Check tail pages before head page information is cleared to | |
1101 | * avoid checking PageCompound for order-0 pages. | |
1102 | */ | |
1103 | if (unlikely(order)) { | |
1104 | bool compound = PageCompound(page); | |
1105 | int i; | |
1106 | ||
1107 | VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); | |
1108 | ||
1109 | if (compound) | |
1110 | page[1].flags &= ~PAGE_FLAGS_SECOND; | |
1111 | for (i = 1; i < (1 << order); i++) { | |
1112 | if (compound) | |
1113 | bad += free_tail_page_prepare(page, page + i); | |
1114 | if (is_check_pages_enabled()) { | |
1115 | if (free_page_is_bad(page + i)) { | |
1116 | bad++; | |
1117 | continue; | |
1118 | } | |
1119 | } | |
1120 | (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; | |
1121 | } | |
1122 | } | |
1123 | if (PageMappingFlags(page)) | |
1124 | page->mapping = NULL; | |
1125 | if (memcg_kmem_online() && PageMemcgKmem(page)) | |
1126 | __memcg_kmem_uncharge_page(page, order); | |
1127 | if (is_check_pages_enabled()) { | |
1128 | if (free_page_is_bad(page)) | |
1129 | bad++; | |
1130 | if (bad) | |
1131 | return false; | |
1132 | } | |
1133 | ||
1134 | page_cpupid_reset_last(page); | |
1135 | page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; | |
1136 | reset_page_owner(page, order); | |
1137 | page_table_check_free(page, order); | |
1138 | ||
1139 | if (!PageHighMem(page)) { | |
1140 | debug_check_no_locks_freed(page_address(page), | |
1141 | PAGE_SIZE << order); | |
1142 | debug_check_no_obj_freed(page_address(page), | |
1143 | PAGE_SIZE << order); | |
1144 | } | |
1145 | ||
1146 | kernel_poison_pages(page, 1 << order); | |
1147 | ||
1148 | /* | |
1149 | * As memory initialization might be integrated into KASAN, | |
1150 | * KASAN poisoning and memory initialization code must be | |
1151 | * kept together to avoid discrepancies in behavior. | |
1152 | * | |
1153 | * With hardware tag-based KASAN, memory tags must be set before the | |
1154 | * page becomes unavailable via debug_pagealloc or arch_free_page. | |
1155 | */ | |
1156 | if (!skip_kasan_poison) { | |
1157 | kasan_poison_pages(page, order, init); | |
1158 | ||
1159 | /* Memory is already initialized if KASAN did it internally. */ | |
1160 | if (kasan_has_integrated_init()) | |
1161 | init = false; | |
1162 | } | |
1163 | if (init) | |
1164 | kernel_init_pages(page, 1 << order); | |
1165 | ||
1166 | /* | |
1167 | * arch_free_page() can make the page's contents inaccessible. s390 | |
1168 | * does this. So nothing which can access the page's contents should | |
1169 | * happen after this. | |
1170 | */ | |
1171 | arch_free_page(page, order); | |
1172 | ||
1173 | debug_pagealloc_unmap_pages(page, 1 << order); | |
1174 | ||
1175 | return true; | |
1176 | } | |
1177 | ||
1178 | /* | |
1179 | * Frees a number of pages from the PCP lists | |
1180 | * Assumes all pages on list are in same zone. | |
1181 | * count is the number of pages to free. | |
1182 | */ | |
1183 | static void free_pcppages_bulk(struct zone *zone, int count, | |
1184 | struct per_cpu_pages *pcp, | |
1185 | int pindex) | |
1186 | { | |
1187 | unsigned long flags; | |
1188 | unsigned int order; | |
1189 | bool isolated_pageblocks; | |
1190 | struct page *page; | |
1191 | ||
1192 | /* | |
1193 | * Ensure proper count is passed which otherwise would stuck in the | |
1194 | * below while (list_empty(list)) loop. | |
1195 | */ | |
1196 | count = min(pcp->count, count); | |
1197 | ||
1198 | /* Ensure requested pindex is drained first. */ | |
1199 | pindex = pindex - 1; | |
1200 | ||
1201 | spin_lock_irqsave(&zone->lock, flags); | |
1202 | isolated_pageblocks = has_isolate_pageblock(zone); | |
1203 | ||
1204 | while (count > 0) { | |
1205 | struct list_head *list; | |
1206 | int nr_pages; | |
1207 | ||
1208 | /* Remove pages from lists in a round-robin fashion. */ | |
1209 | do { | |
1210 | if (++pindex > NR_PCP_LISTS - 1) | |
1211 | pindex = 0; | |
1212 | list = &pcp->lists[pindex]; | |
1213 | } while (list_empty(list)); | |
1214 | ||
1215 | order = pindex_to_order(pindex); | |
1216 | nr_pages = 1 << order; | |
1217 | do { | |
1218 | int mt; | |
1219 | ||
1220 | page = list_last_entry(list, struct page, pcp_list); | |
1221 | mt = get_pcppage_migratetype(page); | |
1222 | ||
1223 | /* must delete to avoid corrupting pcp list */ | |
1224 | list_del(&page->pcp_list); | |
1225 | count -= nr_pages; | |
1226 | pcp->count -= nr_pages; | |
1227 | ||
1228 | /* MIGRATE_ISOLATE page should not go to pcplists */ | |
1229 | VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); | |
1230 | /* Pageblock could have been isolated meanwhile */ | |
1231 | if (unlikely(isolated_pageblocks)) | |
1232 | mt = get_pageblock_migratetype(page); | |
1233 | ||
1234 | __free_one_page(page, page_to_pfn(page), zone, order, mt, FPI_NONE); | |
1235 | trace_mm_page_pcpu_drain(page, order, mt); | |
1236 | } while (count > 0 && !list_empty(list)); | |
1237 | } | |
1238 | ||
1239 | spin_unlock_irqrestore(&zone->lock, flags); | |
1240 | } | |
1241 | ||
1242 | static void free_one_page(struct zone *zone, | |
1243 | struct page *page, unsigned long pfn, | |
1244 | unsigned int order, | |
1245 | int migratetype, fpi_t fpi_flags) | |
1246 | { | |
1247 | unsigned long flags; | |
1248 | ||
1249 | spin_lock_irqsave(&zone->lock, flags); | |
1250 | if (unlikely(has_isolate_pageblock(zone) || | |
1251 | is_migrate_isolate(migratetype))) { | |
1252 | migratetype = get_pfnblock_migratetype(page, pfn); | |
1253 | } | |
1254 | __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); | |
1255 | spin_unlock_irqrestore(&zone->lock, flags); | |
1256 | } | |
1257 | ||
1258 | static void __free_pages_ok(struct page *page, unsigned int order, | |
1259 | fpi_t fpi_flags) | |
1260 | { | |
1261 | unsigned long flags; | |
1262 | int migratetype; | |
1263 | unsigned long pfn = page_to_pfn(page); | |
1264 | struct zone *zone = page_zone(page); | |
1265 | ||
1266 | if (!free_pages_prepare(page, order, fpi_flags)) | |
1267 | return; | |
1268 | ||
1269 | /* | |
1270 | * Calling get_pfnblock_migratetype() without spin_lock_irqsave() here | |
1271 | * is used to avoid calling get_pfnblock_migratetype() under the lock. | |
1272 | * This will reduce the lock holding time. | |
1273 | */ | |
1274 | migratetype = get_pfnblock_migratetype(page, pfn); | |
1275 | ||
1276 | spin_lock_irqsave(&zone->lock, flags); | |
1277 | if (unlikely(has_isolate_pageblock(zone) || | |
1278 | is_migrate_isolate(migratetype))) { | |
1279 | migratetype = get_pfnblock_migratetype(page, pfn); | |
1280 | } | |
1281 | __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); | |
1282 | spin_unlock_irqrestore(&zone->lock, flags); | |
1283 | ||
1284 | __count_vm_events(PGFREE, 1 << order); | |
1285 | } | |
1286 | ||
1287 | void __free_pages_core(struct page *page, unsigned int order) | |
1288 | { | |
1289 | unsigned int nr_pages = 1 << order; | |
1290 | struct page *p = page; | |
1291 | unsigned int loop; | |
1292 | ||
1293 | /* | |
1294 | * When initializing the memmap, __init_single_page() sets the refcount | |
1295 | * of all pages to 1 ("allocated"/"not free"). We have to set the | |
1296 | * refcount of all involved pages to 0. | |
1297 | */ | |
1298 | prefetchw(p); | |
1299 | for (loop = 0; loop < (nr_pages - 1); loop++, p++) { | |
1300 | prefetchw(p + 1); | |
1301 | __ClearPageReserved(p); | |
1302 | set_page_count(p, 0); | |
1303 | } | |
1304 | __ClearPageReserved(p); | |
1305 | set_page_count(p, 0); | |
1306 | ||
1307 | atomic_long_add(nr_pages, &page_zone(page)->managed_pages); | |
1308 | ||
1309 | if (page_contains_unaccepted(page, order)) { | |
1310 | if (order == MAX_ORDER && __free_unaccepted(page)) | |
1311 | return; | |
1312 | ||
1313 | accept_page(page, order); | |
1314 | } | |
1315 | ||
1316 | /* | |
1317 | * Bypass PCP and place fresh pages right to the tail, primarily | |
1318 | * relevant for memory onlining. | |
1319 | */ | |
1320 | __free_pages_ok(page, order, FPI_TO_TAIL); | |
1321 | } | |
1322 | ||
1323 | /* | |
1324 | * Check that the whole (or subset of) a pageblock given by the interval of | |
1325 | * [start_pfn, end_pfn) is valid and within the same zone, before scanning it | |
1326 | * with the migration of free compaction scanner. | |
1327 | * | |
1328 | * Return struct page pointer of start_pfn, or NULL if checks were not passed. | |
1329 | * | |
1330 | * It's possible on some configurations to have a setup like node0 node1 node0 | |
1331 | * i.e. it's possible that all pages within a zones range of pages do not | |
1332 | * belong to a single zone. We assume that a border between node0 and node1 | |
1333 | * can occur within a single pageblock, but not a node0 node1 node0 | |
1334 | * interleaving within a single pageblock. It is therefore sufficient to check | |
1335 | * the first and last page of a pageblock and avoid checking each individual | |
1336 | * page in a pageblock. | |
1337 | * | |
1338 | * Note: the function may return non-NULL struct page even for a page block | |
1339 | * which contains a memory hole (i.e. there is no physical memory for a subset | |
1340 | * of the pfn range). For example, if the pageblock order is MAX_ORDER, which | |
1341 | * will fall into 2 sub-sections, and the end pfn of the pageblock may be hole | |
1342 | * even though the start pfn is online and valid. This should be safe most of | |
1343 | * the time because struct pages are still initialized via init_unavailable_range() | |
1344 | * and pfn walkers shouldn't touch any physical memory range for which they do | |
1345 | * not recognize any specific metadata in struct pages. | |
1346 | */ | |
1347 | struct page *__pageblock_pfn_to_page(unsigned long start_pfn, | |
1348 | unsigned long end_pfn, struct zone *zone) | |
1349 | { | |
1350 | struct page *start_page; | |
1351 | struct page *end_page; | |
1352 | ||
1353 | /* end_pfn is one past the range we are checking */ | |
1354 | end_pfn--; | |
1355 | ||
1356 | if (!pfn_valid(end_pfn)) | |
1357 | return NULL; | |
1358 | ||
1359 | start_page = pfn_to_online_page(start_pfn); | |
1360 | if (!start_page) | |
1361 | return NULL; | |
1362 | ||
1363 | if (page_zone(start_page) != zone) | |
1364 | return NULL; | |
1365 | ||
1366 | end_page = pfn_to_page(end_pfn); | |
1367 | ||
1368 | /* This gives a shorter code than deriving page_zone(end_page) */ | |
1369 | if (page_zone_id(start_page) != page_zone_id(end_page)) | |
1370 | return NULL; | |
1371 | ||
1372 | return start_page; | |
1373 | } | |
1374 | ||
1375 | /* | |
1376 | * The order of subdivision here is critical for the IO subsystem. | |
1377 | * Please do not alter this order without good reasons and regression | |
1378 | * testing. Specifically, as large blocks of memory are subdivided, | |
1379 | * the order in which smaller blocks are delivered depends on the order | |
1380 | * they're subdivided in this function. This is the primary factor | |
1381 | * influencing the order in which pages are delivered to the IO | |
1382 | * subsystem according to empirical testing, and this is also justified | |
1383 | * by considering the behavior of a buddy system containing a single | |
1384 | * large block of memory acted on by a series of small allocations. | |
1385 | * This behavior is a critical factor in sglist merging's success. | |
1386 | * | |
1387 | * -- nyc | |
1388 | */ | |
1389 | static inline void expand(struct zone *zone, struct page *page, | |
1390 | int low, int high, int migratetype) | |
1391 | { | |
1392 | unsigned long size = 1 << high; | |
1393 | ||
1394 | while (high > low) { | |
1395 | high--; | |
1396 | size >>= 1; | |
1397 | VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]); | |
1398 | ||
1399 | /* | |
1400 | * Mark as guard pages (or page), that will allow to | |
1401 | * merge back to allocator when buddy will be freed. | |
1402 | * Corresponding page table entries will not be touched, | |
1403 | * pages will stay not present in virtual address space | |
1404 | */ | |
1405 | if (set_page_guard(zone, &page[size], high, migratetype)) | |
1406 | continue; | |
1407 | ||
1408 | add_to_free_list(&page[size], zone, high, migratetype); | |
1409 | set_buddy_order(&page[size], high); | |
1410 | } | |
1411 | } | |
1412 | ||
1413 | static void check_new_page_bad(struct page *page) | |
1414 | { | |
1415 | if (unlikely(page->flags & __PG_HWPOISON)) { | |
1416 | /* Don't complain about hwpoisoned pages */ | |
1417 | page_mapcount_reset(page); /* remove PageBuddy */ | |
1418 | return; | |
1419 | } | |
1420 | ||
1421 | bad_page(page, | |
1422 | page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP)); | |
1423 | } | |
1424 | ||
1425 | /* | |
1426 | * This page is about to be returned from the page allocator | |
1427 | */ | |
1428 | static int check_new_page(struct page *page) | |
1429 | { | |
1430 | if (likely(page_expected_state(page, | |
1431 | PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON))) | |
1432 | return 0; | |
1433 | ||
1434 | check_new_page_bad(page); | |
1435 | return 1; | |
1436 | } | |
1437 | ||
1438 | static inline bool check_new_pages(struct page *page, unsigned int order) | |
1439 | { | |
1440 | if (is_check_pages_enabled()) { | |
1441 | for (int i = 0; i < (1 << order); i++) { | |
1442 | struct page *p = page + i; | |
1443 | ||
1444 | if (check_new_page(p)) | |
1445 | return true; | |
1446 | } | |
1447 | } | |
1448 | ||
1449 | return false; | |
1450 | } | |
1451 | ||
1452 | static inline bool should_skip_kasan_unpoison(gfp_t flags) | |
1453 | { | |
1454 | /* Don't skip if a software KASAN mode is enabled. */ | |
1455 | if (IS_ENABLED(CONFIG_KASAN_GENERIC) || | |
1456 | IS_ENABLED(CONFIG_KASAN_SW_TAGS)) | |
1457 | return false; | |
1458 | ||
1459 | /* Skip, if hardware tag-based KASAN is not enabled. */ | |
1460 | if (!kasan_hw_tags_enabled()) | |
1461 | return true; | |
1462 | ||
1463 | /* | |
1464 | * With hardware tag-based KASAN enabled, skip if this has been | |
1465 | * requested via __GFP_SKIP_KASAN. | |
1466 | */ | |
1467 | return flags & __GFP_SKIP_KASAN; | |
1468 | } | |
1469 | ||
1470 | static inline bool should_skip_init(gfp_t flags) | |
1471 | { | |
1472 | /* Don't skip, if hardware tag-based KASAN is not enabled. */ | |
1473 | if (!kasan_hw_tags_enabled()) | |
1474 | return false; | |
1475 | ||
1476 | /* For hardware tag-based KASAN, skip if requested. */ | |
1477 | return (flags & __GFP_SKIP_ZERO); | |
1478 | } | |
1479 | ||
1480 | inline void post_alloc_hook(struct page *page, unsigned int order, | |
1481 | gfp_t gfp_flags) | |
1482 | { | |
1483 | bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) && | |
1484 | !should_skip_init(gfp_flags); | |
1485 | bool zero_tags = init && (gfp_flags & __GFP_ZEROTAGS); | |
1486 | int i; | |
1487 | ||
1488 | set_page_private(page, 0); | |
1489 | set_page_refcounted(page); | |
1490 | ||
1491 | arch_alloc_page(page, order); | |
1492 | debug_pagealloc_map_pages(page, 1 << order); | |
1493 | ||
1494 | /* | |
1495 | * Page unpoisoning must happen before memory initialization. | |
1496 | * Otherwise, the poison pattern will be overwritten for __GFP_ZERO | |
1497 | * allocations and the page unpoisoning code will complain. | |
1498 | */ | |
1499 | kernel_unpoison_pages(page, 1 << order); | |
1500 | ||
1501 | /* | |
1502 | * As memory initialization might be integrated into KASAN, | |
1503 | * KASAN unpoisoning and memory initializion code must be | |
1504 | * kept together to avoid discrepancies in behavior. | |
1505 | */ | |
1506 | ||
1507 | /* | |
1508 | * If memory tags should be zeroed | |
1509 | * (which happens only when memory should be initialized as well). | |
1510 | */ | |
1511 | if (zero_tags) { | |
1512 | /* Initialize both memory and memory tags. */ | |
1513 | for (i = 0; i != 1 << order; ++i) | |
1514 | tag_clear_highpage(page + i); | |
1515 | ||
1516 | /* Take note that memory was initialized by the loop above. */ | |
1517 | init = false; | |
1518 | } | |
1519 | if (!should_skip_kasan_unpoison(gfp_flags) && | |
1520 | kasan_unpoison_pages(page, order, init)) { | |
1521 | /* Take note that memory was initialized by KASAN. */ | |
1522 | if (kasan_has_integrated_init()) | |
1523 | init = false; | |
1524 | } else { | |
1525 | /* | |
1526 | * If memory tags have not been set by KASAN, reset the page | |
1527 | * tags to ensure page_address() dereferencing does not fault. | |
1528 | */ | |
1529 | for (i = 0; i != 1 << order; ++i) | |
1530 | page_kasan_tag_reset(page + i); | |
1531 | } | |
1532 | /* If memory is still not initialized, initialize it now. */ | |
1533 | if (init) | |
1534 | kernel_init_pages(page, 1 << order); | |
1535 | ||
1536 | set_page_owner(page, order, gfp_flags); | |
1537 | page_table_check_alloc(page, order); | |
1538 | } | |
1539 | ||
1540 | static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, | |
1541 | unsigned int alloc_flags) | |
1542 | { | |
1543 | post_alloc_hook(page, order, gfp_flags); | |
1544 | ||
1545 | if (order && (gfp_flags & __GFP_COMP)) | |
1546 | prep_compound_page(page, order); | |
1547 | ||
1548 | /* | |
1549 | * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to | |
1550 | * allocate the page. The expectation is that the caller is taking | |
1551 | * steps that will free more memory. The caller should avoid the page | |
1552 | * being used for !PFMEMALLOC purposes. | |
1553 | */ | |
1554 | if (alloc_flags & ALLOC_NO_WATERMARKS) | |
1555 | set_page_pfmemalloc(page); | |
1556 | else | |
1557 | clear_page_pfmemalloc(page); | |
1558 | } | |
1559 | ||
1560 | /* | |
1561 | * Go through the free lists for the given migratetype and remove | |
1562 | * the smallest available page from the freelists | |
1563 | */ | |
1564 | static __always_inline | |
1565 | struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, | |
1566 | int migratetype) | |
1567 | { | |
1568 | unsigned int current_order; | |
1569 | struct free_area *area; | |
1570 | struct page *page; | |
1571 | ||
1572 | /* Find a page of the appropriate size in the preferred list */ | |
1573 | for (current_order = order; current_order <= MAX_ORDER; ++current_order) { | |
1574 | area = &(zone->free_area[current_order]); | |
1575 | page = get_page_from_free_area(area, migratetype); | |
1576 | if (!page) | |
1577 | continue; | |
1578 | del_page_from_free_list(page, zone, current_order); | |
1579 | expand(zone, page, order, current_order, migratetype); | |
1580 | set_pcppage_migratetype(page, migratetype); | |
1581 | trace_mm_page_alloc_zone_locked(page, order, migratetype, | |
1582 | pcp_allowed_order(order) && | |
1583 | migratetype < MIGRATE_PCPTYPES); | |
1584 | return page; | |
1585 | } | |
1586 | ||
1587 | return NULL; | |
1588 | } | |
1589 | ||
1590 | ||
1591 | /* | |
1592 | * This array describes the order lists are fallen back to when | |
1593 | * the free lists for the desirable migrate type are depleted | |
1594 | * | |
1595 | * The other migratetypes do not have fallbacks. | |
1596 | */ | |
1597 | static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = { | |
1598 | [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE }, | |
1599 | [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE }, | |
1600 | [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE }, | |
1601 | }; | |
1602 | ||
1603 | #ifdef CONFIG_CMA | |
1604 | static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone, | |
1605 | unsigned int order) | |
1606 | { | |
1607 | return __rmqueue_smallest(zone, order, MIGRATE_CMA); | |
1608 | } | |
1609 | #else | |
1610 | static inline struct page *__rmqueue_cma_fallback(struct zone *zone, | |
1611 | unsigned int order) { return NULL; } | |
1612 | #endif | |
1613 | ||
1614 | /* | |
1615 | * Move the free pages in a range to the freelist tail of the requested type. | |
1616 | * Note that start_page and end_pages are not aligned on a pageblock | |
1617 | * boundary. If alignment is required, use move_freepages_block() | |
1618 | */ | |
1619 | static int move_freepages(struct zone *zone, | |
1620 | unsigned long start_pfn, unsigned long end_pfn, | |
1621 | int migratetype, int *num_movable) | |
1622 | { | |
1623 | struct page *page; | |
1624 | unsigned long pfn; | |
1625 | unsigned int order; | |
1626 | int pages_moved = 0; | |
1627 | ||
1628 | for (pfn = start_pfn; pfn <= end_pfn;) { | |
1629 | page = pfn_to_page(pfn); | |
1630 | if (!PageBuddy(page)) { | |
1631 | /* | |
1632 | * We assume that pages that could be isolated for | |
1633 | * migration are movable. But we don't actually try | |
1634 | * isolating, as that would be expensive. | |
1635 | */ | |
1636 | if (num_movable && | |
1637 | (PageLRU(page) || __PageMovable(page))) | |
1638 | (*num_movable)++; | |
1639 | pfn++; | |
1640 | continue; | |
1641 | } | |
1642 | ||
1643 | /* Make sure we are not inadvertently changing nodes */ | |
1644 | VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); | |
1645 | VM_BUG_ON_PAGE(page_zone(page) != zone, page); | |
1646 | ||
1647 | order = buddy_order(page); | |
1648 | move_to_free_list(page, zone, order, migratetype); | |
1649 | pfn += 1 << order; | |
1650 | pages_moved += 1 << order; | |
1651 | } | |
1652 | ||
1653 | return pages_moved; | |
1654 | } | |
1655 | ||
1656 | int move_freepages_block(struct zone *zone, struct page *page, | |
1657 | int migratetype, int *num_movable) | |
1658 | { | |
1659 | unsigned long start_pfn, end_pfn, pfn; | |
1660 | ||
1661 | if (num_movable) | |
1662 | *num_movable = 0; | |
1663 | ||
1664 | pfn = page_to_pfn(page); | |
1665 | start_pfn = pageblock_start_pfn(pfn); | |
1666 | end_pfn = pageblock_end_pfn(pfn) - 1; | |
1667 | ||
1668 | /* Do not cross zone boundaries */ | |
1669 | if (!zone_spans_pfn(zone, start_pfn)) | |
1670 | start_pfn = pfn; | |
1671 | if (!zone_spans_pfn(zone, end_pfn)) | |
1672 | return 0; | |
1673 | ||
1674 | return move_freepages(zone, start_pfn, end_pfn, migratetype, | |
1675 | num_movable); | |
1676 | } | |
1677 | ||
1678 | static void change_pageblock_range(struct page *pageblock_page, | |
1679 | int start_order, int migratetype) | |
1680 | { | |
1681 | int nr_pageblocks = 1 << (start_order - pageblock_order); | |
1682 | ||
1683 | while (nr_pageblocks--) { | |
1684 | set_pageblock_migratetype(pageblock_page, migratetype); | |
1685 | pageblock_page += pageblock_nr_pages; | |
1686 | } | |
1687 | } | |
1688 | ||
1689 | /* | |
1690 | * When we are falling back to another migratetype during allocation, try to | |
1691 | * steal extra free pages from the same pageblocks to satisfy further | |
1692 | * allocations, instead of polluting multiple pageblocks. | |
1693 | * | |
1694 | * If we are stealing a relatively large buddy page, it is likely there will | |
1695 | * be more free pages in the pageblock, so try to steal them all. For | |
1696 | * reclaimable and unmovable allocations, we steal regardless of page size, | |
1697 | * as fragmentation caused by those allocations polluting movable pageblocks | |
1698 | * is worse than movable allocations stealing from unmovable and reclaimable | |
1699 | * pageblocks. | |
1700 | */ | |
1701 | static bool can_steal_fallback(unsigned int order, int start_mt) | |
1702 | { | |
1703 | /* | |
1704 | * Leaving this order check is intended, although there is | |
1705 | * relaxed order check in next check. The reason is that | |
1706 | * we can actually steal whole pageblock if this condition met, | |
1707 | * but, below check doesn't guarantee it and that is just heuristic | |
1708 | * so could be changed anytime. | |
1709 | */ | |
1710 | if (order >= pageblock_order) | |
1711 | return true; | |
1712 | ||
1713 | if (order >= pageblock_order / 2 || | |
1714 | start_mt == MIGRATE_RECLAIMABLE || | |
1715 | start_mt == MIGRATE_UNMOVABLE || | |
1716 | page_group_by_mobility_disabled) | |
1717 | return true; | |
1718 | ||
1719 | return false; | |
1720 | } | |
1721 | ||
1722 | static inline bool boost_watermark(struct zone *zone) | |
1723 | { | |
1724 | unsigned long max_boost; | |
1725 | ||
1726 | if (!watermark_boost_factor) | |
1727 | return false; | |
1728 | /* | |
1729 | * Don't bother in zones that are unlikely to produce results. | |
1730 | * On small machines, including kdump capture kernels running | |
1731 | * in a small area, boosting the watermark can cause an out of | |
1732 | * memory situation immediately. | |
1733 | */ | |
1734 | if ((pageblock_nr_pages * 4) > zone_managed_pages(zone)) | |
1735 | return false; | |
1736 | ||
1737 | max_boost = mult_frac(zone->_watermark[WMARK_HIGH], | |
1738 | watermark_boost_factor, 10000); | |
1739 | ||
1740 | /* | |
1741 | * high watermark may be uninitialised if fragmentation occurs | |
1742 | * very early in boot so do not boost. We do not fall | |
1743 | * through and boost by pageblock_nr_pages as failing | |
1744 | * allocations that early means that reclaim is not going | |
1745 | * to help and it may even be impossible to reclaim the | |
1746 | * boosted watermark resulting in a hang. | |
1747 | */ | |
1748 | if (!max_boost) | |
1749 | return false; | |
1750 | ||
1751 | max_boost = max(pageblock_nr_pages, max_boost); | |
1752 | ||
1753 | zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages, | |
1754 | max_boost); | |
1755 | ||
1756 | return true; | |
1757 | } | |
1758 | ||
1759 | /* | |
1760 | * This function implements actual steal behaviour. If order is large enough, | |
1761 | * we can steal whole pageblock. If not, we first move freepages in this | |
1762 | * pageblock to our migratetype and determine how many already-allocated pages | |
1763 | * are there in the pageblock with a compatible migratetype. If at least half | |
1764 | * of pages are free or compatible, we can change migratetype of the pageblock | |
1765 | * itself, so pages freed in the future will be put on the correct free list. | |
1766 | */ | |
1767 | static void steal_suitable_fallback(struct zone *zone, struct page *page, | |
1768 | unsigned int alloc_flags, int start_type, bool whole_block) | |
1769 | { | |
1770 | unsigned int current_order = buddy_order(page); | |
1771 | int free_pages, movable_pages, alike_pages; | |
1772 | int old_block_type; | |
1773 | ||
1774 | old_block_type = get_pageblock_migratetype(page); | |
1775 | ||
1776 | /* | |
1777 | * This can happen due to races and we want to prevent broken | |
1778 | * highatomic accounting. | |
1779 | */ | |
1780 | if (is_migrate_highatomic(old_block_type)) | |
1781 | goto single_page; | |
1782 | ||
1783 | /* Take ownership for orders >= pageblock_order */ | |
1784 | if (current_order >= pageblock_order) { | |
1785 | change_pageblock_range(page, current_order, start_type); | |
1786 | goto single_page; | |
1787 | } | |
1788 | ||
1789 | /* | |
1790 | * Boost watermarks to increase reclaim pressure to reduce the | |
1791 | * likelihood of future fallbacks. Wake kswapd now as the node | |
1792 | * may be balanced overall and kswapd will not wake naturally. | |
1793 | */ | |
1794 | if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD)) | |
1795 | set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); | |
1796 | ||
1797 | /* We are not allowed to try stealing from the whole block */ | |
1798 | if (!whole_block) | |
1799 | goto single_page; | |
1800 | ||
1801 | free_pages = move_freepages_block(zone, page, start_type, | |
1802 | &movable_pages); | |
1803 | /* moving whole block can fail due to zone boundary conditions */ | |
1804 | if (!free_pages) | |
1805 | goto single_page; | |
1806 | ||
1807 | /* | |
1808 | * Determine how many pages are compatible with our allocation. | |
1809 | * For movable allocation, it's the number of movable pages which | |
1810 | * we just obtained. For other types it's a bit more tricky. | |
1811 | */ | |
1812 | if (start_type == MIGRATE_MOVABLE) { | |
1813 | alike_pages = movable_pages; | |
1814 | } else { | |
1815 | /* | |
1816 | * If we are falling back a RECLAIMABLE or UNMOVABLE allocation | |
1817 | * to MOVABLE pageblock, consider all non-movable pages as | |
1818 | * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or | |
1819 | * vice versa, be conservative since we can't distinguish the | |
1820 | * exact migratetype of non-movable pages. | |
1821 | */ | |
1822 | if (old_block_type == MIGRATE_MOVABLE) | |
1823 | alike_pages = pageblock_nr_pages | |
1824 | - (free_pages + movable_pages); | |
1825 | else | |
1826 | alike_pages = 0; | |
1827 | } | |
1828 | /* | |
1829 | * If a sufficient number of pages in the block are either free or of | |
1830 | * compatible migratability as our allocation, claim the whole block. | |
1831 | */ | |
1832 | if (free_pages + alike_pages >= (1 << (pageblock_order-1)) || | |
1833 | page_group_by_mobility_disabled) | |
1834 | set_pageblock_migratetype(page, start_type); | |
1835 | ||
1836 | return; | |
1837 | ||
1838 | single_page: | |
1839 | move_to_free_list(page, zone, current_order, start_type); | |
1840 | } | |
1841 | ||
1842 | /* | |
1843 | * Check whether there is a suitable fallback freepage with requested order. | |
1844 | * If only_stealable is true, this function returns fallback_mt only if | |
1845 | * we can steal other freepages all together. This would help to reduce | |
1846 | * fragmentation due to mixed migratetype pages in one pageblock. | |
1847 | */ | |
1848 | int find_suitable_fallback(struct free_area *area, unsigned int order, | |
1849 | int migratetype, bool only_stealable, bool *can_steal) | |
1850 | { | |
1851 | int i; | |
1852 | int fallback_mt; | |
1853 | ||
1854 | if (area->nr_free == 0) | |
1855 | return -1; | |
1856 | ||
1857 | *can_steal = false; | |
1858 | for (i = 0; i < MIGRATE_PCPTYPES - 1 ; i++) { | |
1859 | fallback_mt = fallbacks[migratetype][i]; | |
1860 | if (free_area_empty(area, fallback_mt)) | |
1861 | continue; | |
1862 | ||
1863 | if (can_steal_fallback(order, migratetype)) | |
1864 | *can_steal = true; | |
1865 | ||
1866 | if (!only_stealable) | |
1867 | return fallback_mt; | |
1868 | ||
1869 | if (*can_steal) | |
1870 | return fallback_mt; | |
1871 | } | |
1872 | ||
1873 | return -1; | |
1874 | } | |
1875 | ||
1876 | /* | |
1877 | * Reserve a pageblock for exclusive use of high-order atomic allocations if | |
1878 | * there are no empty page blocks that contain a page with a suitable order | |
1879 | */ | |
1880 | static void reserve_highatomic_pageblock(struct page *page, struct zone *zone) | |
1881 | { | |
1882 | int mt; | |
1883 | unsigned long max_managed, flags; | |
1884 | ||
1885 | /* | |
1886 | * Limit the number reserved to 1 pageblock or roughly 1% of a zone. | |
1887 | * Check is race-prone but harmless. | |
1888 | */ | |
1889 | max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages; | |
1890 | if (zone->nr_reserved_highatomic >= max_managed) | |
1891 | return; | |
1892 | ||
1893 | spin_lock_irqsave(&zone->lock, flags); | |
1894 | ||
1895 | /* Recheck the nr_reserved_highatomic limit under the lock */ | |
1896 | if (zone->nr_reserved_highatomic >= max_managed) | |
1897 | goto out_unlock; | |
1898 | ||
1899 | /* Yoink! */ | |
1900 | mt = get_pageblock_migratetype(page); | |
1901 | /* Only reserve normal pageblocks (i.e., they can merge with others) */ | |
1902 | if (migratetype_is_mergeable(mt)) { | |
1903 | zone->nr_reserved_highatomic += pageblock_nr_pages; | |
1904 | set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); | |
1905 | move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); | |
1906 | } | |
1907 | ||
1908 | out_unlock: | |
1909 | spin_unlock_irqrestore(&zone->lock, flags); | |
1910 | } | |
1911 | ||
1912 | /* | |
1913 | * Used when an allocation is about to fail under memory pressure. This | |
1914 | * potentially hurts the reliability of high-order allocations when under | |
1915 | * intense memory pressure but failed atomic allocations should be easier | |
1916 | * to recover from than an OOM. | |
1917 | * | |
1918 | * If @force is true, try to unreserve a pageblock even though highatomic | |
1919 | * pageblock is exhausted. | |
1920 | */ | |
1921 | static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, | |
1922 | bool force) | |
1923 | { | |
1924 | struct zonelist *zonelist = ac->zonelist; | |
1925 | unsigned long flags; | |
1926 | struct zoneref *z; | |
1927 | struct zone *zone; | |
1928 | struct page *page; | |
1929 | int order; | |
1930 | bool ret; | |
1931 | ||
1932 | for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx, | |
1933 | ac->nodemask) { | |
1934 | /* | |
1935 | * Preserve at least one pageblock unless memory pressure | |
1936 | * is really high. | |
1937 | */ | |
1938 | if (!force && zone->nr_reserved_highatomic <= | |
1939 | pageblock_nr_pages) | |
1940 | continue; | |
1941 | ||
1942 | spin_lock_irqsave(&zone->lock, flags); | |
1943 | for (order = 0; order <= MAX_ORDER; order++) { | |
1944 | struct free_area *area = &(zone->free_area[order]); | |
1945 | ||
1946 | page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC); | |
1947 | if (!page) | |
1948 | continue; | |
1949 | ||
1950 | /* | |
1951 | * In page freeing path, migratetype change is racy so | |
1952 | * we can counter several free pages in a pageblock | |
1953 | * in this loop although we changed the pageblock type | |
1954 | * from highatomic to ac->migratetype. So we should | |
1955 | * adjust the count once. | |
1956 | */ | |
1957 | if (is_migrate_highatomic_page(page)) { | |
1958 | /* | |
1959 | * It should never happen but changes to | |
1960 | * locking could inadvertently allow a per-cpu | |
1961 | * drain to add pages to MIGRATE_HIGHATOMIC | |
1962 | * while unreserving so be safe and watch for | |
1963 | * underflows. | |
1964 | */ | |
1965 | zone->nr_reserved_highatomic -= min( | |
1966 | pageblock_nr_pages, | |
1967 | zone->nr_reserved_highatomic); | |
1968 | } | |
1969 | ||
1970 | /* | |
1971 | * Convert to ac->migratetype and avoid the normal | |
1972 | * pageblock stealing heuristics. Minimally, the caller | |
1973 | * is doing the work and needs the pages. More | |
1974 | * importantly, if the block was always converted to | |
1975 | * MIGRATE_UNMOVABLE or another type then the number | |
1976 | * of pageblocks that cannot be completely freed | |
1977 | * may increase. | |
1978 | */ | |
1979 | set_pageblock_migratetype(page, ac->migratetype); | |
1980 | ret = move_freepages_block(zone, page, ac->migratetype, | |
1981 | NULL); | |
1982 | if (ret) { | |
1983 | spin_unlock_irqrestore(&zone->lock, flags); | |
1984 | return ret; | |
1985 | } | |
1986 | } | |
1987 | spin_unlock_irqrestore(&zone->lock, flags); | |
1988 | } | |
1989 | ||
1990 | return false; | |
1991 | } | |
1992 | ||
1993 | /* | |
1994 | * Try finding a free buddy page on the fallback list and put it on the free | |
1995 | * list of requested migratetype, possibly along with other pages from the same | |
1996 | * block, depending on fragmentation avoidance heuristics. Returns true if | |
1997 | * fallback was found so that __rmqueue_smallest() can grab it. | |
1998 | * | |
1999 | * The use of signed ints for order and current_order is a deliberate | |
2000 | * deviation from the rest of this file, to make the for loop | |
2001 | * condition simpler. | |
2002 | */ | |
2003 | static __always_inline bool | |
2004 | __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, | |
2005 | unsigned int alloc_flags) | |
2006 | { | |
2007 | struct free_area *area; | |
2008 | int current_order; | |
2009 | int min_order = order; | |
2010 | struct page *page; | |
2011 | int fallback_mt; | |
2012 | bool can_steal; | |
2013 | ||
2014 | /* | |
2015 | * Do not steal pages from freelists belonging to other pageblocks | |
2016 | * i.e. orders < pageblock_order. If there are no local zones free, | |
2017 | * the zonelists will be reiterated without ALLOC_NOFRAGMENT. | |
2018 | */ | |
2019 | if (order < pageblock_order && alloc_flags & ALLOC_NOFRAGMENT) | |
2020 | min_order = pageblock_order; | |
2021 | ||
2022 | /* | |
2023 | * Find the largest available free page in the other list. This roughly | |
2024 | * approximates finding the pageblock with the most free pages, which | |
2025 | * would be too costly to do exactly. | |
2026 | */ | |
2027 | for (current_order = MAX_ORDER; current_order >= min_order; | |
2028 | --current_order) { | |
2029 | area = &(zone->free_area[current_order]); | |
2030 | fallback_mt = find_suitable_fallback(area, current_order, | |
2031 | start_migratetype, false, &can_steal); | |
2032 | if (fallback_mt == -1) | |
2033 | continue; | |
2034 | ||
2035 | /* | |
2036 | * We cannot steal all free pages from the pageblock and the | |
2037 | * requested migratetype is movable. In that case it's better to | |
2038 | * steal and split the smallest available page instead of the | |
2039 | * largest available page, because even if the next movable | |
2040 | * allocation falls back into a different pageblock than this | |
2041 | * one, it won't cause permanent fragmentation. | |
2042 | */ | |
2043 | if (!can_steal && start_migratetype == MIGRATE_MOVABLE | |
2044 | && current_order > order) | |
2045 | goto find_smallest; | |
2046 | ||
2047 | goto do_steal; | |
2048 | } | |
2049 | ||
2050 | return false; | |
2051 | ||
2052 | find_smallest: | |
2053 | for (current_order = order; current_order <= MAX_ORDER; | |
2054 | current_order++) { | |
2055 | area = &(zone->free_area[current_order]); | |
2056 | fallback_mt = find_suitable_fallback(area, current_order, | |
2057 | start_migratetype, false, &can_steal); | |
2058 | if (fallback_mt != -1) | |
2059 | break; | |
2060 | } | |
2061 | ||
2062 | /* | |
2063 | * This should not happen - we already found a suitable fallback | |
2064 | * when looking for the largest page. | |
2065 | */ | |
2066 | VM_BUG_ON(current_order > MAX_ORDER); | |
2067 | ||
2068 | do_steal: | |
2069 | page = get_page_from_free_area(area, fallback_mt); | |
2070 | ||
2071 | steal_suitable_fallback(zone, page, alloc_flags, start_migratetype, | |
2072 | can_steal); | |
2073 | ||
2074 | trace_mm_page_alloc_extfrag(page, order, current_order, | |
2075 | start_migratetype, fallback_mt); | |
2076 | ||
2077 | return true; | |
2078 | ||
2079 | } | |
2080 | ||
2081 | /* | |
2082 | * Do the hard work of removing an element from the buddy allocator. | |
2083 | * Call me with the zone->lock already held. | |
2084 | */ | |
2085 | static __always_inline struct page * | |
2086 | __rmqueue(struct zone *zone, unsigned int order, int migratetype, | |
2087 | unsigned int alloc_flags) | |
2088 | { | |
2089 | struct page *page; | |
2090 | ||
2091 | if (IS_ENABLED(CONFIG_CMA)) { | |
2092 | /* | |
2093 | * Balance movable allocations between regular and CMA areas by | |
2094 | * allocating from CMA when over half of the zone's free memory | |
2095 | * is in the CMA area. | |
2096 | */ | |
2097 | if (alloc_flags & ALLOC_CMA && | |
2098 | zone_page_state(zone, NR_FREE_CMA_PAGES) > | |
2099 | zone_page_state(zone, NR_FREE_PAGES) / 2) { | |
2100 | page = __rmqueue_cma_fallback(zone, order); | |
2101 | if (page) | |
2102 | return page; | |
2103 | } | |
2104 | } | |
2105 | retry: | |
2106 | page = __rmqueue_smallest(zone, order, migratetype); | |
2107 | if (unlikely(!page)) { | |
2108 | if (alloc_flags & ALLOC_CMA) | |
2109 | page = __rmqueue_cma_fallback(zone, order); | |
2110 | ||
2111 | if (!page && __rmqueue_fallback(zone, order, migratetype, | |
2112 | alloc_flags)) | |
2113 | goto retry; | |
2114 | } | |
2115 | return page; | |
2116 | } | |
2117 | ||
2118 | /* | |
2119 | * Obtain a specified number of elements from the buddy allocator, all under | |
2120 | * a single hold of the lock, for efficiency. Add them to the supplied list. | |
2121 | * Returns the number of new pages which were placed at *list. | |
2122 | */ | |
2123 | static int rmqueue_bulk(struct zone *zone, unsigned int order, | |
2124 | unsigned long count, struct list_head *list, | |
2125 | int migratetype, unsigned int alloc_flags) | |
2126 | { | |
2127 | unsigned long flags; | |
2128 | int i; | |
2129 | ||
2130 | spin_lock_irqsave(&zone->lock, flags); | |
2131 | for (i = 0; i < count; ++i) { | |
2132 | struct page *page = __rmqueue(zone, order, migratetype, | |
2133 | alloc_flags); | |
2134 | if (unlikely(page == NULL)) | |
2135 | break; | |
2136 | ||
2137 | /* | |
2138 | * Split buddy pages returned by expand() are received here in | |
2139 | * physical page order. The page is added to the tail of | |
2140 | * caller's list. From the callers perspective, the linked list | |
2141 | * is ordered by page number under some conditions. This is | |
2142 | * useful for IO devices that can forward direction from the | |
2143 | * head, thus also in the physical page order. This is useful | |
2144 | * for IO devices that can merge IO requests if the physical | |
2145 | * pages are ordered properly. | |
2146 | */ | |
2147 | list_add_tail(&page->pcp_list, list); | |
2148 | if (is_migrate_cma(get_pcppage_migratetype(page))) | |
2149 | __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, | |
2150 | -(1 << order)); | |
2151 | } | |
2152 | ||
2153 | __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); | |
2154 | spin_unlock_irqrestore(&zone->lock, flags); | |
2155 | ||
2156 | return i; | |
2157 | } | |
2158 | ||
2159 | #ifdef CONFIG_NUMA | |
2160 | /* | |
2161 | * Called from the vmstat counter updater to drain pagesets of this | |
2162 | * currently executing processor on remote nodes after they have | |
2163 | * expired. | |
2164 | */ | |
2165 | void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) | |
2166 | { | |
2167 | int to_drain, batch; | |
2168 | ||
2169 | batch = READ_ONCE(pcp->batch); | |
2170 | to_drain = min(pcp->count, batch); | |
2171 | if (to_drain > 0) { | |
2172 | spin_lock(&pcp->lock); | |
2173 | free_pcppages_bulk(zone, to_drain, pcp, 0); | |
2174 | spin_unlock(&pcp->lock); | |
2175 | } | |
2176 | } | |
2177 | #endif | |
2178 | ||
2179 | /* | |
2180 | * Drain pcplists of the indicated processor and zone. | |
2181 | */ | |
2182 | static void drain_pages_zone(unsigned int cpu, struct zone *zone) | |
2183 | { | |
2184 | struct per_cpu_pages *pcp; | |
2185 | ||
2186 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); | |
2187 | if (pcp->count) { | |
2188 | spin_lock(&pcp->lock); | |
2189 | free_pcppages_bulk(zone, pcp->count, pcp, 0); | |
2190 | spin_unlock(&pcp->lock); | |
2191 | } | |
2192 | } | |
2193 | ||
2194 | /* | |
2195 | * Drain pcplists of all zones on the indicated processor. | |
2196 | */ | |
2197 | static void drain_pages(unsigned int cpu) | |
2198 | { | |
2199 | struct zone *zone; | |
2200 | ||
2201 | for_each_populated_zone(zone) { | |
2202 | drain_pages_zone(cpu, zone); | |
2203 | } | |
2204 | } | |
2205 | ||
2206 | /* | |
2207 | * Spill all of this CPU's per-cpu pages back into the buddy allocator. | |
2208 | */ | |
2209 | void drain_local_pages(struct zone *zone) | |
2210 | { | |
2211 | int cpu = smp_processor_id(); | |
2212 | ||
2213 | if (zone) | |
2214 | drain_pages_zone(cpu, zone); | |
2215 | else | |
2216 | drain_pages(cpu); | |
2217 | } | |
2218 | ||
2219 | /* | |
2220 | * The implementation of drain_all_pages(), exposing an extra parameter to | |
2221 | * drain on all cpus. | |
2222 | * | |
2223 | * drain_all_pages() is optimized to only execute on cpus where pcplists are | |
2224 | * not empty. The check for non-emptiness can however race with a free to | |
2225 | * pcplist that has not yet increased the pcp->count from 0 to 1. Callers | |
2226 | * that need the guarantee that every CPU has drained can disable the | |
2227 | * optimizing racy check. | |
2228 | */ | |
2229 | static void __drain_all_pages(struct zone *zone, bool force_all_cpus) | |
2230 | { | |
2231 | int cpu; | |
2232 | ||
2233 | /* | |
2234 | * Allocate in the BSS so we won't require allocation in | |
2235 | * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y | |
2236 | */ | |
2237 | static cpumask_t cpus_with_pcps; | |
2238 | ||
2239 | /* | |
2240 | * Do not drain if one is already in progress unless it's specific to | |
2241 | * a zone. Such callers are primarily CMA and memory hotplug and need | |
2242 | * the drain to be complete when the call returns. | |
2243 | */ | |
2244 | if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) { | |
2245 | if (!zone) | |
2246 | return; | |
2247 | mutex_lock(&pcpu_drain_mutex); | |
2248 | } | |
2249 | ||
2250 | /* | |
2251 | * We don't care about racing with CPU hotplug event | |
2252 | * as offline notification will cause the notified | |
2253 | * cpu to drain that CPU pcps and on_each_cpu_mask | |
2254 | * disables preemption as part of its processing | |
2255 | */ | |
2256 | for_each_online_cpu(cpu) { | |
2257 | struct per_cpu_pages *pcp; | |
2258 | struct zone *z; | |
2259 | bool has_pcps = false; | |
2260 | ||
2261 | if (force_all_cpus) { | |
2262 | /* | |
2263 | * The pcp.count check is racy, some callers need a | |
2264 | * guarantee that no cpu is missed. | |
2265 | */ | |
2266 | has_pcps = true; | |
2267 | } else if (zone) { | |
2268 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); | |
2269 | if (pcp->count) | |
2270 | has_pcps = true; | |
2271 | } else { | |
2272 | for_each_populated_zone(z) { | |
2273 | pcp = per_cpu_ptr(z->per_cpu_pageset, cpu); | |
2274 | if (pcp->count) { | |
2275 | has_pcps = true; | |
2276 | break; | |
2277 | } | |
2278 | } | |
2279 | } | |
2280 | ||
2281 | if (has_pcps) | |
2282 | cpumask_set_cpu(cpu, &cpus_with_pcps); | |
2283 | else | |
2284 | cpumask_clear_cpu(cpu, &cpus_with_pcps); | |
2285 | } | |
2286 | ||
2287 | for_each_cpu(cpu, &cpus_with_pcps) { | |
2288 | if (zone) | |
2289 | drain_pages_zone(cpu, zone); | |
2290 | else | |
2291 | drain_pages(cpu); | |
2292 | } | |
2293 | ||
2294 | mutex_unlock(&pcpu_drain_mutex); | |
2295 | } | |
2296 | ||
2297 | /* | |
2298 | * Spill all the per-cpu pages from all CPUs back into the buddy allocator. | |
2299 | * | |
2300 | * When zone parameter is non-NULL, spill just the single zone's pages. | |
2301 | */ | |
2302 | void drain_all_pages(struct zone *zone) | |
2303 | { | |
2304 | __drain_all_pages(zone, false); | |
2305 | } | |
2306 | ||
2307 | static bool free_unref_page_prepare(struct page *page, unsigned long pfn, | |
2308 | unsigned int order) | |
2309 | { | |
2310 | int migratetype; | |
2311 | ||
2312 | if (!free_pages_prepare(page, order, FPI_NONE)) | |
2313 | return false; | |
2314 | ||
2315 | migratetype = get_pfnblock_migratetype(page, pfn); | |
2316 | set_pcppage_migratetype(page, migratetype); | |
2317 | return true; | |
2318 | } | |
2319 | ||
2320 | static int nr_pcp_free(struct per_cpu_pages *pcp, int high, bool free_high) | |
2321 | { | |
2322 | int min_nr_free, max_nr_free; | |
2323 | int batch = READ_ONCE(pcp->batch); | |
2324 | ||
2325 | /* Free everything if batch freeing high-order pages. */ | |
2326 | if (unlikely(free_high)) | |
2327 | return pcp->count; | |
2328 | ||
2329 | /* Check for PCP disabled or boot pageset */ | |
2330 | if (unlikely(high < batch)) | |
2331 | return 1; | |
2332 | ||
2333 | /* Leave at least pcp->batch pages on the list */ | |
2334 | min_nr_free = batch; | |
2335 | max_nr_free = high - batch; | |
2336 | ||
2337 | /* | |
2338 | * Double the number of pages freed each time there is subsequent | |
2339 | * freeing of pages without any allocation. | |
2340 | */ | |
2341 | batch <<= pcp->free_factor; | |
2342 | if (batch < max_nr_free) | |
2343 | pcp->free_factor++; | |
2344 | batch = clamp(batch, min_nr_free, max_nr_free); | |
2345 | ||
2346 | return batch; | |
2347 | } | |
2348 | ||
2349 | static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, | |
2350 | bool free_high) | |
2351 | { | |
2352 | int high = READ_ONCE(pcp->high); | |
2353 | ||
2354 | if (unlikely(!high || free_high)) | |
2355 | return 0; | |
2356 | ||
2357 | if (!test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) | |
2358 | return high; | |
2359 | ||
2360 | /* | |
2361 | * If reclaim is active, limit the number of pages that can be | |
2362 | * stored on pcp lists | |
2363 | */ | |
2364 | return min(READ_ONCE(pcp->batch) << 2, high); | |
2365 | } | |
2366 | ||
2367 | static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, | |
2368 | struct page *page, int migratetype, | |
2369 | unsigned int order) | |
2370 | { | |
2371 | int high; | |
2372 | int pindex; | |
2373 | bool free_high; | |
2374 | ||
2375 | __count_vm_events(PGFREE, 1 << order); | |
2376 | pindex = order_to_pindex(migratetype, order); | |
2377 | list_add(&page->pcp_list, &pcp->lists[pindex]); | |
2378 | pcp->count += 1 << order; | |
2379 | ||
2380 | /* | |
2381 | * As high-order pages other than THP's stored on PCP can contribute | |
2382 | * to fragmentation, limit the number stored when PCP is heavily | |
2383 | * freeing without allocation. The remainder after bulk freeing | |
2384 | * stops will be drained from vmstat refresh context. | |
2385 | */ | |
2386 | free_high = (pcp->free_factor && order && order <= PAGE_ALLOC_COSTLY_ORDER); | |
2387 | ||
2388 | high = nr_pcp_high(pcp, zone, free_high); | |
2389 | if (pcp->count >= high) { | |
2390 | free_pcppages_bulk(zone, nr_pcp_free(pcp, high, free_high), pcp, pindex); | |
2391 | } | |
2392 | } | |
2393 | ||
2394 | /* | |
2395 | * Free a pcp page | |
2396 | */ | |
2397 | void free_unref_page(struct page *page, unsigned int order) | |
2398 | { | |
2399 | unsigned long __maybe_unused UP_flags; | |
2400 | struct per_cpu_pages *pcp; | |
2401 | struct zone *zone; | |
2402 | unsigned long pfn = page_to_pfn(page); | |
2403 | int migratetype; | |
2404 | ||
2405 | if (!free_unref_page_prepare(page, pfn, order)) | |
2406 | return; | |
2407 | ||
2408 | /* | |
2409 | * We only track unmovable, reclaimable and movable on pcp lists. | |
2410 | * Place ISOLATE pages on the isolated list because they are being | |
2411 | * offlined but treat HIGHATOMIC as movable pages so we can get those | |
2412 | * areas back if necessary. Otherwise, we may have to free | |
2413 | * excessively into the page allocator | |
2414 | */ | |
2415 | migratetype = get_pcppage_migratetype(page); | |
2416 | if (unlikely(migratetype >= MIGRATE_PCPTYPES)) { | |
2417 | if (unlikely(is_migrate_isolate(migratetype))) { | |
2418 | free_one_page(page_zone(page), page, pfn, order, migratetype, FPI_NONE); | |
2419 | return; | |
2420 | } | |
2421 | migratetype = MIGRATE_MOVABLE; | |
2422 | } | |
2423 | ||
2424 | zone = page_zone(page); | |
2425 | pcp_trylock_prepare(UP_flags); | |
2426 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); | |
2427 | if (pcp) { | |
2428 | free_unref_page_commit(zone, pcp, page, migratetype, order); | |
2429 | pcp_spin_unlock(pcp); | |
2430 | } else { | |
2431 | free_one_page(zone, page, pfn, order, migratetype, FPI_NONE); | |
2432 | } | |
2433 | pcp_trylock_finish(UP_flags); | |
2434 | } | |
2435 | ||
2436 | /* | |
2437 | * Free a list of 0-order pages | |
2438 | */ | |
2439 | void free_unref_page_list(struct list_head *list) | |
2440 | { | |
2441 | unsigned long __maybe_unused UP_flags; | |
2442 | struct page *page, *next; | |
2443 | struct per_cpu_pages *pcp = NULL; | |
2444 | struct zone *locked_zone = NULL; | |
2445 | int batch_count = 0; | |
2446 | int migratetype; | |
2447 | ||
2448 | /* Prepare pages for freeing */ | |
2449 | list_for_each_entry_safe(page, next, list, lru) { | |
2450 | unsigned long pfn = page_to_pfn(page); | |
2451 | if (!free_unref_page_prepare(page, pfn, 0)) { | |
2452 | list_del(&page->lru); | |
2453 | continue; | |
2454 | } | |
2455 | ||
2456 | /* | |
2457 | * Free isolated pages directly to the allocator, see | |
2458 | * comment in free_unref_page. | |
2459 | */ | |
2460 | migratetype = get_pcppage_migratetype(page); | |
2461 | if (unlikely(is_migrate_isolate(migratetype))) { | |
2462 | list_del(&page->lru); | |
2463 | free_one_page(page_zone(page), page, pfn, 0, migratetype, FPI_NONE); | |
2464 | continue; | |
2465 | } | |
2466 | } | |
2467 | ||
2468 | list_for_each_entry_safe(page, next, list, lru) { | |
2469 | struct zone *zone = page_zone(page); | |
2470 | ||
2471 | list_del(&page->lru); | |
2472 | migratetype = get_pcppage_migratetype(page); | |
2473 | ||
2474 | /* | |
2475 | * Either different zone requiring a different pcp lock or | |
2476 | * excessive lock hold times when freeing a large list of | |
2477 | * pages. | |
2478 | */ | |
2479 | if (zone != locked_zone || batch_count == SWAP_CLUSTER_MAX) { | |
2480 | if (pcp) { | |
2481 | pcp_spin_unlock(pcp); | |
2482 | pcp_trylock_finish(UP_flags); | |
2483 | } | |
2484 | ||
2485 | batch_count = 0; | |
2486 | ||
2487 | /* | |
2488 | * trylock is necessary as pages may be getting freed | |
2489 | * from IRQ or SoftIRQ context after an IO completion. | |
2490 | */ | |
2491 | pcp_trylock_prepare(UP_flags); | |
2492 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); | |
2493 | if (unlikely(!pcp)) { | |
2494 | pcp_trylock_finish(UP_flags); | |
2495 | free_one_page(zone, page, page_to_pfn(page), | |
2496 | 0, migratetype, FPI_NONE); | |
2497 | locked_zone = NULL; | |
2498 | continue; | |
2499 | } | |
2500 | locked_zone = zone; | |
2501 | } | |
2502 | ||
2503 | /* | |
2504 | * Non-isolated types over MIGRATE_PCPTYPES get added | |
2505 | * to the MIGRATE_MOVABLE pcp list. | |
2506 | */ | |
2507 | if (unlikely(migratetype >= MIGRATE_PCPTYPES)) | |
2508 | migratetype = MIGRATE_MOVABLE; | |
2509 | ||
2510 | trace_mm_page_free_batched(page); | |
2511 | free_unref_page_commit(zone, pcp, page, migratetype, 0); | |
2512 | batch_count++; | |
2513 | } | |
2514 | ||
2515 | if (pcp) { | |
2516 | pcp_spin_unlock(pcp); | |
2517 | pcp_trylock_finish(UP_flags); | |
2518 | } | |
2519 | } | |
2520 | ||
2521 | /* | |
2522 | * split_page takes a non-compound higher-order page, and splits it into | |
2523 | * n (1<<order) sub-pages: page[0..n] | |
2524 | * Each sub-page must be freed individually. | |
2525 | * | |
2526 | * Note: this is probably too low level an operation for use in drivers. | |
2527 | * Please consult with lkml before using this in your driver. | |
2528 | */ | |
2529 | void split_page(struct page *page, unsigned int order) | |
2530 | { | |
2531 | int i; | |
2532 | ||
2533 | VM_BUG_ON_PAGE(PageCompound(page), page); | |
2534 | VM_BUG_ON_PAGE(!page_count(page), page); | |
2535 | ||
2536 | for (i = 1; i < (1 << order); i++) | |
2537 | set_page_refcounted(page + i); | |
2538 | split_page_owner(page, 1 << order); | |
2539 | split_page_memcg(page, 1 << order); | |
2540 | } | |
2541 | EXPORT_SYMBOL_GPL(split_page); | |
2542 | ||
2543 | int __isolate_free_page(struct page *page, unsigned int order) | |
2544 | { | |
2545 | struct zone *zone = page_zone(page); | |
2546 | int mt = get_pageblock_migratetype(page); | |
2547 | ||
2548 | if (!is_migrate_isolate(mt)) { | |
2549 | unsigned long watermark; | |
2550 | /* | |
2551 | * Obey watermarks as if the page was being allocated. We can | |
2552 | * emulate a high-order watermark check with a raised order-0 | |
2553 | * watermark, because we already know our high-order page | |
2554 | * exists. | |
2555 | */ | |
2556 | watermark = zone->_watermark[WMARK_MIN] + (1UL << order); | |
2557 | if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA)) | |
2558 | return 0; | |
2559 | ||
2560 | __mod_zone_freepage_state(zone, -(1UL << order), mt); | |
2561 | } | |
2562 | ||
2563 | del_page_from_free_list(page, zone, order); | |
2564 | ||
2565 | /* | |
2566 | * Set the pageblock if the isolated page is at least half of a | |
2567 | * pageblock | |
2568 | */ | |
2569 | if (order >= pageblock_order - 1) { | |
2570 | struct page *endpage = page + (1 << order) - 1; | |
2571 | for (; page < endpage; page += pageblock_nr_pages) { | |
2572 | int mt = get_pageblock_migratetype(page); | |
2573 | /* | |
2574 | * Only change normal pageblocks (i.e., they can merge | |
2575 | * with others) | |
2576 | */ | |
2577 | if (migratetype_is_mergeable(mt)) | |
2578 | set_pageblock_migratetype(page, | |
2579 | MIGRATE_MOVABLE); | |
2580 | } | |
2581 | } | |
2582 | ||
2583 | return 1UL << order; | |
2584 | } | |
2585 | ||
2586 | /** | |
2587 | * __putback_isolated_page - Return a now-isolated page back where we got it | |
2588 | * @page: Page that was isolated | |
2589 | * @order: Order of the isolated page | |
2590 | * @mt: The page's pageblock's migratetype | |
2591 | * | |
2592 | * This function is meant to return a page pulled from the free lists via | |
2593 | * __isolate_free_page back to the free lists they were pulled from. | |
2594 | */ | |
2595 | void __putback_isolated_page(struct page *page, unsigned int order, int mt) | |
2596 | { | |
2597 | struct zone *zone = page_zone(page); | |
2598 | ||
2599 | /* zone lock should be held when this function is called */ | |
2600 | lockdep_assert_held(&zone->lock); | |
2601 | ||
2602 | /* Return isolated page to tail of freelist. */ | |
2603 | __free_one_page(page, page_to_pfn(page), zone, order, mt, | |
2604 | FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL); | |
2605 | } | |
2606 | ||
2607 | /* | |
2608 | * Update NUMA hit/miss statistics | |
2609 | */ | |
2610 | static inline void zone_statistics(struct zone *preferred_zone, struct zone *z, | |
2611 | long nr_account) | |
2612 | { | |
2613 | #ifdef CONFIG_NUMA | |
2614 | enum numa_stat_item local_stat = NUMA_LOCAL; | |
2615 | ||
2616 | /* skip numa counters update if numa stats is disabled */ | |
2617 | if (!static_branch_likely(&vm_numa_stat_key)) | |
2618 | return; | |
2619 | ||
2620 | if (zone_to_nid(z) != numa_node_id()) | |
2621 | local_stat = NUMA_OTHER; | |
2622 | ||
2623 | if (zone_to_nid(z) == zone_to_nid(preferred_zone)) | |
2624 | __count_numa_events(z, NUMA_HIT, nr_account); | |
2625 | else { | |
2626 | __count_numa_events(z, NUMA_MISS, nr_account); | |
2627 | __count_numa_events(preferred_zone, NUMA_FOREIGN, nr_account); | |
2628 | } | |
2629 | __count_numa_events(z, local_stat, nr_account); | |
2630 | #endif | |
2631 | } | |
2632 | ||
2633 | static __always_inline | |
2634 | struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, | |
2635 | unsigned int order, unsigned int alloc_flags, | |
2636 | int migratetype) | |
2637 | { | |
2638 | struct page *page; | |
2639 | unsigned long flags; | |
2640 | ||
2641 | do { | |
2642 | page = NULL; | |
2643 | spin_lock_irqsave(&zone->lock, flags); | |
2644 | if (alloc_flags & ALLOC_HIGHATOMIC) | |
2645 | page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); | |
2646 | if (!page) { | |
2647 | page = __rmqueue(zone, order, migratetype, alloc_flags); | |
2648 | ||
2649 | /* | |
2650 | * If the allocation fails, allow OOM handling access | |
2651 | * to HIGHATOMIC reserves as failing now is worse than | |
2652 | * failing a high-order atomic allocation in the | |
2653 | * future. | |
2654 | */ | |
2655 | if (!page && (alloc_flags & ALLOC_OOM)) | |
2656 | page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); | |
2657 | ||
2658 | if (!page) { | |
2659 | spin_unlock_irqrestore(&zone->lock, flags); | |
2660 | return NULL; | |
2661 | } | |
2662 | } | |
2663 | __mod_zone_freepage_state(zone, -(1 << order), | |
2664 | get_pcppage_migratetype(page)); | |
2665 | spin_unlock_irqrestore(&zone->lock, flags); | |
2666 | } while (check_new_pages(page, order)); | |
2667 | ||
2668 | __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); | |
2669 | zone_statistics(preferred_zone, zone, 1); | |
2670 | ||
2671 | return page; | |
2672 | } | |
2673 | ||
2674 | /* Remove page from the per-cpu list, caller must protect the list */ | |
2675 | static inline | |
2676 | struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, | |
2677 | int migratetype, | |
2678 | unsigned int alloc_flags, | |
2679 | struct per_cpu_pages *pcp, | |
2680 | struct list_head *list) | |
2681 | { | |
2682 | struct page *page; | |
2683 | ||
2684 | do { | |
2685 | if (list_empty(list)) { | |
2686 | int batch = READ_ONCE(pcp->batch); | |
2687 | int alloced; | |
2688 | ||
2689 | /* | |
2690 | * Scale batch relative to order if batch implies | |
2691 | * free pages can be stored on the PCP. Batch can | |
2692 | * be 1 for small zones or for boot pagesets which | |
2693 | * should never store free pages as the pages may | |
2694 | * belong to arbitrary zones. | |
2695 | */ | |
2696 | if (batch > 1) | |
2697 | batch = max(batch >> order, 2); | |
2698 | alloced = rmqueue_bulk(zone, order, | |
2699 | batch, list, | |
2700 | migratetype, alloc_flags); | |
2701 | ||
2702 | pcp->count += alloced << order; | |
2703 | if (unlikely(list_empty(list))) | |
2704 | return NULL; | |
2705 | } | |
2706 | ||
2707 | page = list_first_entry(list, struct page, pcp_list); | |
2708 | list_del(&page->pcp_list); | |
2709 | pcp->count -= 1 << order; | |
2710 | } while (check_new_pages(page, order)); | |
2711 | ||
2712 | return page; | |
2713 | } | |
2714 | ||
2715 | /* Lock and remove page from the per-cpu list */ | |
2716 | static struct page *rmqueue_pcplist(struct zone *preferred_zone, | |
2717 | struct zone *zone, unsigned int order, | |
2718 | int migratetype, unsigned int alloc_flags) | |
2719 | { | |
2720 | struct per_cpu_pages *pcp; | |
2721 | struct list_head *list; | |
2722 | struct page *page; | |
2723 | unsigned long __maybe_unused UP_flags; | |
2724 | ||
2725 | /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ | |
2726 | pcp_trylock_prepare(UP_flags); | |
2727 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); | |
2728 | if (!pcp) { | |
2729 | pcp_trylock_finish(UP_flags); | |
2730 | return NULL; | |
2731 | } | |
2732 | ||
2733 | /* | |
2734 | * On allocation, reduce the number of pages that are batch freed. | |
2735 | * See nr_pcp_free() where free_factor is increased for subsequent | |
2736 | * frees. | |
2737 | */ | |
2738 | pcp->free_factor >>= 1; | |
2739 | list = &pcp->lists[order_to_pindex(migratetype, order)]; | |
2740 | page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list); | |
2741 | pcp_spin_unlock(pcp); | |
2742 | pcp_trylock_finish(UP_flags); | |
2743 | if (page) { | |
2744 | __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); | |
2745 | zone_statistics(preferred_zone, zone, 1); | |
2746 | } | |
2747 | return page; | |
2748 | } | |
2749 | ||
2750 | /* | |
2751 | * Allocate a page from the given zone. | |
2752 | * Use pcplists for THP or "cheap" high-order allocations. | |
2753 | */ | |
2754 | ||
2755 | /* | |
2756 | * Do not instrument rmqueue() with KMSAN. This function may call | |
2757 | * __msan_poison_alloca() through a call to set_pfnblock_flags_mask(). | |
2758 | * If __msan_poison_alloca() attempts to allocate pages for the stack depot, it | |
2759 | * may call rmqueue() again, which will result in a deadlock. | |
2760 | */ | |
2761 | __no_sanitize_memory | |
2762 | static inline | |
2763 | struct page *rmqueue(struct zone *preferred_zone, | |
2764 | struct zone *zone, unsigned int order, | |
2765 | gfp_t gfp_flags, unsigned int alloc_flags, | |
2766 | int migratetype) | |
2767 | { | |
2768 | struct page *page; | |
2769 | ||
2770 | /* | |
2771 | * We most definitely don't want callers attempting to | |
2772 | * allocate greater than order-1 page units with __GFP_NOFAIL. | |
2773 | */ | |
2774 | WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); | |
2775 | ||
2776 | if (likely(pcp_allowed_order(order))) { | |
2777 | page = rmqueue_pcplist(preferred_zone, zone, order, | |
2778 | migratetype, alloc_flags); | |
2779 | if (likely(page)) | |
2780 | goto out; | |
2781 | } | |
2782 | ||
2783 | page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags, | |
2784 | migratetype); | |
2785 | ||
2786 | out: | |
2787 | /* Separate test+clear to avoid unnecessary atomics */ | |
2788 | if ((alloc_flags & ALLOC_KSWAPD) && | |
2789 | unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { | |
2790 | clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); | |
2791 | wakeup_kswapd(zone, 0, 0, zone_idx(zone)); | |
2792 | } | |
2793 | ||
2794 | VM_BUG_ON_PAGE(page && bad_range(zone, page), page); | |
2795 | return page; | |
2796 | } | |
2797 | ||
2798 | noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) | |
2799 | { | |
2800 | return __should_fail_alloc_page(gfp_mask, order); | |
2801 | } | |
2802 | ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE); | |
2803 | ||
2804 | static inline long __zone_watermark_unusable_free(struct zone *z, | |
2805 | unsigned int order, unsigned int alloc_flags) | |
2806 | { | |
2807 | long unusable_free = (1 << order) - 1; | |
2808 | ||
2809 | /* | |
2810 | * If the caller does not have rights to reserves below the min | |
2811 | * watermark then subtract the high-atomic reserves. This will | |
2812 | * over-estimate the size of the atomic reserve but it avoids a search. | |
2813 | */ | |
2814 | if (likely(!(alloc_flags & ALLOC_RESERVES))) | |
2815 | unusable_free += z->nr_reserved_highatomic; | |
2816 | ||
2817 | #ifdef CONFIG_CMA | |
2818 | /* If allocation can't use CMA areas don't use free CMA pages */ | |
2819 | if (!(alloc_flags & ALLOC_CMA)) | |
2820 | unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); | |
2821 | #endif | |
2822 | #ifdef CONFIG_UNACCEPTED_MEMORY | |
2823 | unusable_free += zone_page_state(z, NR_UNACCEPTED); | |
2824 | #endif | |
2825 | ||
2826 | return unusable_free; | |
2827 | } | |
2828 | ||
2829 | /* | |
2830 | * Return true if free base pages are above 'mark'. For high-order checks it | |
2831 | * will return true of the order-0 watermark is reached and there is at least | |
2832 | * one free page of a suitable size. Checking now avoids taking the zone lock | |
2833 | * to check in the allocation paths if no pages are free. | |
2834 | */ | |
2835 | bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, | |
2836 | int highest_zoneidx, unsigned int alloc_flags, | |
2837 | long free_pages) | |
2838 | { | |
2839 | long min = mark; | |
2840 | int o; | |
2841 | ||
2842 | /* free_pages may go negative - that's OK */ | |
2843 | free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); | |
2844 | ||
2845 | if (unlikely(alloc_flags & ALLOC_RESERVES)) { | |
2846 | /* | |
2847 | * __GFP_HIGH allows access to 50% of the min reserve as well | |
2848 | * as OOM. | |
2849 | */ | |
2850 | if (alloc_flags & ALLOC_MIN_RESERVE) { | |
2851 | min -= min / 2; | |
2852 | ||
2853 | /* | |
2854 | * Non-blocking allocations (e.g. GFP_ATOMIC) can | |
2855 | * access more reserves than just __GFP_HIGH. Other | |
2856 | * non-blocking allocations requests such as GFP_NOWAIT | |
2857 | * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get | |
2858 | * access to the min reserve. | |
2859 | */ | |
2860 | if (alloc_flags & ALLOC_NON_BLOCK) | |
2861 | min -= min / 4; | |
2862 | } | |
2863 | ||
2864 | /* | |
2865 | * OOM victims can try even harder than the normal reserve | |
2866 | * users on the grounds that it's definitely going to be in | |
2867 | * the exit path shortly and free memory. Any allocation it | |
2868 | * makes during the free path will be small and short-lived. | |
2869 | */ | |
2870 | if (alloc_flags & ALLOC_OOM) | |
2871 | min -= min / 2; | |
2872 | } | |
2873 | ||
2874 | /* | |
2875 | * Check watermarks for an order-0 allocation request. If these | |
2876 | * are not met, then a high-order request also cannot go ahead | |
2877 | * even if a suitable page happened to be free. | |
2878 | */ | |
2879 | if (free_pages <= min + z->lowmem_reserve[highest_zoneidx]) | |
2880 | return false; | |
2881 | ||
2882 | /* If this is an order-0 request then the watermark is fine */ | |
2883 | if (!order) | |
2884 | return true; | |
2885 | ||
2886 | /* For a high-order request, check at least one suitable page is free */ | |
2887 | for (o = order; o <= MAX_ORDER; o++) { | |
2888 | struct free_area *area = &z->free_area[o]; | |
2889 | int mt; | |
2890 | ||
2891 | if (!area->nr_free) | |
2892 | continue; | |
2893 | ||
2894 | for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) { | |
2895 | if (!free_area_empty(area, mt)) | |
2896 | return true; | |
2897 | } | |
2898 | ||
2899 | #ifdef CONFIG_CMA | |
2900 | if ((alloc_flags & ALLOC_CMA) && | |
2901 | !free_area_empty(area, MIGRATE_CMA)) { | |
2902 | return true; | |
2903 | } | |
2904 | #endif | |
2905 | if ((alloc_flags & (ALLOC_HIGHATOMIC|ALLOC_OOM)) && | |
2906 | !free_area_empty(area, MIGRATE_HIGHATOMIC)) { | |
2907 | return true; | |
2908 | } | |
2909 | } | |
2910 | return false; | |
2911 | } | |
2912 | ||
2913 | bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, | |
2914 | int highest_zoneidx, unsigned int alloc_flags) | |
2915 | { | |
2916 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, | |
2917 | zone_page_state(z, NR_FREE_PAGES)); | |
2918 | } | |
2919 | ||
2920 | static inline bool zone_watermark_fast(struct zone *z, unsigned int order, | |
2921 | unsigned long mark, int highest_zoneidx, | |
2922 | unsigned int alloc_flags, gfp_t gfp_mask) | |
2923 | { | |
2924 | long free_pages; | |
2925 | ||
2926 | free_pages = zone_page_state(z, NR_FREE_PAGES); | |
2927 | ||
2928 | /* | |
2929 | * Fast check for order-0 only. If this fails then the reserves | |
2930 | * need to be calculated. | |
2931 | */ | |
2932 | if (!order) { | |
2933 | long usable_free; | |
2934 | long reserved; | |
2935 | ||
2936 | usable_free = free_pages; | |
2937 | reserved = __zone_watermark_unusable_free(z, 0, alloc_flags); | |
2938 | ||
2939 | /* reserved may over estimate high-atomic reserves. */ | |
2940 | usable_free -= min(usable_free, reserved); | |
2941 | if (usable_free > mark + z->lowmem_reserve[highest_zoneidx]) | |
2942 | return true; | |
2943 | } | |
2944 | ||
2945 | if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, | |
2946 | free_pages)) | |
2947 | return true; | |
2948 | ||
2949 | /* | |
2950 | * Ignore watermark boosting for __GFP_HIGH order-0 allocations | |
2951 | * when checking the min watermark. The min watermark is the | |
2952 | * point where boosting is ignored so that kswapd is woken up | |
2953 | * when below the low watermark. | |
2954 | */ | |
2955 | if (unlikely(!order && (alloc_flags & ALLOC_MIN_RESERVE) && z->watermark_boost | |
2956 | && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) { | |
2957 | mark = z->_watermark[WMARK_MIN]; | |
2958 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, | |
2959 | alloc_flags, free_pages); | |
2960 | } | |
2961 | ||
2962 | return false; | |
2963 | } | |
2964 | ||
2965 | bool zone_watermark_ok_safe(struct zone *z, unsigned int order, | |
2966 | unsigned long mark, int highest_zoneidx) | |
2967 | { | |
2968 | long free_pages = zone_page_state(z, NR_FREE_PAGES); | |
2969 | ||
2970 | if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) | |
2971 | free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES); | |
2972 | ||
2973 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0, | |
2974 | free_pages); | |
2975 | } | |
2976 | ||
2977 | #ifdef CONFIG_NUMA | |
2978 | int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE; | |
2979 | ||
2980 | static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) | |
2981 | { | |
2982 | return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <= | |
2983 | node_reclaim_distance; | |
2984 | } | |
2985 | #else /* CONFIG_NUMA */ | |
2986 | static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) | |
2987 | { | |
2988 | return true; | |
2989 | } | |
2990 | #endif /* CONFIG_NUMA */ | |
2991 | ||
2992 | /* | |
2993 | * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid | |
2994 | * fragmentation is subtle. If the preferred zone was HIGHMEM then | |
2995 | * premature use of a lower zone may cause lowmem pressure problems that | |
2996 | * are worse than fragmentation. If the next zone is ZONE_DMA then it is | |
2997 | * probably too small. It only makes sense to spread allocations to avoid | |
2998 | * fragmentation between the Normal and DMA32 zones. | |
2999 | */ | |
3000 | static inline unsigned int | |
3001 | alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) | |
3002 | { | |
3003 | unsigned int alloc_flags; | |
3004 | ||
3005 | /* | |
3006 | * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD | |
3007 | * to save a branch. | |
3008 | */ | |
3009 | alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM); | |
3010 | ||
3011 | #ifdef CONFIG_ZONE_DMA32 | |
3012 | if (!zone) | |
3013 | return alloc_flags; | |
3014 | ||
3015 | if (zone_idx(zone) != ZONE_NORMAL) | |
3016 | return alloc_flags; | |
3017 | ||
3018 | /* | |
3019 | * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and | |
3020 | * the pointer is within zone->zone_pgdat->node_zones[]. Also assume | |
3021 | * on UMA that if Normal is populated then so is DMA32. | |
3022 | */ | |
3023 | BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1); | |
3024 | if (nr_online_nodes > 1 && !populated_zone(--zone)) | |
3025 | return alloc_flags; | |
3026 | ||
3027 | alloc_flags |= ALLOC_NOFRAGMENT; | |
3028 | #endif /* CONFIG_ZONE_DMA32 */ | |
3029 | return alloc_flags; | |
3030 | } | |
3031 | ||
3032 | /* Must be called after current_gfp_context() which can change gfp_mask */ | |
3033 | static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask, | |
3034 | unsigned int alloc_flags) | |
3035 | { | |
3036 | #ifdef CONFIG_CMA | |
3037 | if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) | |
3038 | alloc_flags |= ALLOC_CMA; | |
3039 | #endif | |
3040 | return alloc_flags; | |
3041 | } | |
3042 | ||
3043 | /* | |
3044 | * get_page_from_freelist goes through the zonelist trying to allocate | |
3045 | * a page. | |
3046 | */ | |
3047 | static struct page * | |
3048 | get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, | |
3049 | const struct alloc_context *ac) | |
3050 | { | |
3051 | struct zoneref *z; | |
3052 | struct zone *zone; | |
3053 | struct pglist_data *last_pgdat = NULL; | |
3054 | bool last_pgdat_dirty_ok = false; | |
3055 | bool no_fallback; | |
3056 | ||
3057 | retry: | |
3058 | /* | |
3059 | * Scan zonelist, looking for a zone with enough free. | |
3060 | * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c. | |
3061 | */ | |
3062 | no_fallback = alloc_flags & ALLOC_NOFRAGMENT; | |
3063 | z = ac->preferred_zoneref; | |
3064 | for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx, | |
3065 | ac->nodemask) { | |
3066 | struct page *page; | |
3067 | unsigned long mark; | |
3068 | ||
3069 | if (cpusets_enabled() && | |
3070 | (alloc_flags & ALLOC_CPUSET) && | |
3071 | !__cpuset_zone_allowed(zone, gfp_mask)) | |
3072 | continue; | |
3073 | /* | |
3074 | * When allocating a page cache page for writing, we | |
3075 | * want to get it from a node that is within its dirty | |
3076 | * limit, such that no single node holds more than its | |
3077 | * proportional share of globally allowed dirty pages. | |
3078 | * The dirty limits take into account the node's | |
3079 | * lowmem reserves and high watermark so that kswapd | |
3080 | * should be able to balance it without having to | |
3081 | * write pages from its LRU list. | |
3082 | * | |
3083 | * XXX: For now, allow allocations to potentially | |
3084 | * exceed the per-node dirty limit in the slowpath | |
3085 | * (spread_dirty_pages unset) before going into reclaim, | |
3086 | * which is important when on a NUMA setup the allowed | |
3087 | * nodes are together not big enough to reach the | |
3088 | * global limit. The proper fix for these situations | |
3089 | * will require awareness of nodes in the | |
3090 | * dirty-throttling and the flusher threads. | |
3091 | */ | |
3092 | if (ac->spread_dirty_pages) { | |
3093 | if (last_pgdat != zone->zone_pgdat) { | |
3094 | last_pgdat = zone->zone_pgdat; | |
3095 | last_pgdat_dirty_ok = node_dirty_ok(zone->zone_pgdat); | |
3096 | } | |
3097 | ||
3098 | if (!last_pgdat_dirty_ok) | |
3099 | continue; | |
3100 | } | |
3101 | ||
3102 | if (no_fallback && nr_online_nodes > 1 && | |
3103 | zone != ac->preferred_zoneref->zone) { | |
3104 | int local_nid; | |
3105 | ||
3106 | /* | |
3107 | * If moving to a remote node, retry but allow | |
3108 | * fragmenting fallbacks. Locality is more important | |
3109 | * than fragmentation avoidance. | |
3110 | */ | |
3111 | local_nid = zone_to_nid(ac->preferred_zoneref->zone); | |
3112 | if (zone_to_nid(zone) != local_nid) { | |
3113 | alloc_flags &= ~ALLOC_NOFRAGMENT; | |
3114 | goto retry; | |
3115 | } | |
3116 | } | |
3117 | ||
3118 | mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); | |
3119 | if (!zone_watermark_fast(zone, order, mark, | |
3120 | ac->highest_zoneidx, alloc_flags, | |
3121 | gfp_mask)) { | |
3122 | int ret; | |
3123 | ||
3124 | if (has_unaccepted_memory()) { | |
3125 | if (try_to_accept_memory(zone, order)) | |
3126 | goto try_this_zone; | |
3127 | } | |
3128 | ||
3129 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT | |
3130 | /* | |
3131 | * Watermark failed for this zone, but see if we can | |
3132 | * grow this zone if it contains deferred pages. | |
3133 | */ | |
3134 | if (deferred_pages_enabled()) { | |
3135 | if (_deferred_grow_zone(zone, order)) | |
3136 | goto try_this_zone; | |
3137 | } | |
3138 | #endif | |
3139 | /* Checked here to keep the fast path fast */ | |
3140 | BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); | |
3141 | if (alloc_flags & ALLOC_NO_WATERMARKS) | |
3142 | goto try_this_zone; | |
3143 | ||
3144 | if (!node_reclaim_enabled() || | |
3145 | !zone_allows_reclaim(ac->preferred_zoneref->zone, zone)) | |
3146 | continue; | |
3147 | ||
3148 | ret = node_reclaim(zone->zone_pgdat, gfp_mask, order); | |
3149 | switch (ret) { | |
3150 | case NODE_RECLAIM_NOSCAN: | |
3151 | /* did not scan */ | |
3152 | continue; | |
3153 | case NODE_RECLAIM_FULL: | |
3154 | /* scanned but unreclaimable */ | |
3155 | continue; | |
3156 | default: | |
3157 | /* did we reclaim enough */ | |
3158 | if (zone_watermark_ok(zone, order, mark, | |
3159 | ac->highest_zoneidx, alloc_flags)) | |
3160 | goto try_this_zone; | |
3161 | ||
3162 | continue; | |
3163 | } | |
3164 | } | |
3165 | ||
3166 | try_this_zone: | |
3167 | page = rmqueue(ac->preferred_zoneref->zone, zone, order, | |
3168 | gfp_mask, alloc_flags, ac->migratetype); | |
3169 | if (page) { | |
3170 | prep_new_page(page, order, gfp_mask, alloc_flags); | |
3171 | ||
3172 | /* | |
3173 | * If this is a high-order atomic allocation then check | |
3174 | * if the pageblock should be reserved for the future | |
3175 | */ | |
3176 | if (unlikely(alloc_flags & ALLOC_HIGHATOMIC)) | |
3177 | reserve_highatomic_pageblock(page, zone); | |
3178 | ||
3179 | return page; | |
3180 | } else { | |
3181 | if (has_unaccepted_memory()) { | |
3182 | if (try_to_accept_memory(zone, order)) | |
3183 | goto try_this_zone; | |
3184 | } | |
3185 | ||
3186 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT | |
3187 | /* Try again if zone has deferred pages */ | |
3188 | if (deferred_pages_enabled()) { | |
3189 | if (_deferred_grow_zone(zone, order)) | |
3190 | goto try_this_zone; | |
3191 | } | |
3192 | #endif | |
3193 | } | |
3194 | } | |
3195 | ||
3196 | /* | |
3197 | * It's possible on a UMA machine to get through all zones that are | |
3198 | * fragmented. If avoiding fragmentation, reset and try again. | |
3199 | */ | |
3200 | if (no_fallback) { | |
3201 | alloc_flags &= ~ALLOC_NOFRAGMENT; | |
3202 | goto retry; | |
3203 | } | |
3204 | ||
3205 | return NULL; | |
3206 | } | |
3207 | ||
3208 | static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask) | |
3209 | { | |
3210 | unsigned int filter = SHOW_MEM_FILTER_NODES; | |
3211 | ||
3212 | /* | |
3213 | * This documents exceptions given to allocations in certain | |
3214 | * contexts that are allowed to allocate outside current's set | |
3215 | * of allowed nodes. | |
3216 | */ | |
3217 | if (!(gfp_mask & __GFP_NOMEMALLOC)) | |
3218 | if (tsk_is_oom_victim(current) || | |
3219 | (current->flags & (PF_MEMALLOC | PF_EXITING))) | |
3220 | filter &= ~SHOW_MEM_FILTER_NODES; | |
3221 | if (!in_task() || !(gfp_mask & __GFP_DIRECT_RECLAIM)) | |
3222 | filter &= ~SHOW_MEM_FILTER_NODES; | |
3223 | ||
3224 | __show_mem(filter, nodemask, gfp_zone(gfp_mask)); | |
3225 | } | |
3226 | ||
3227 | void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) | |
3228 | { | |
3229 | struct va_format vaf; | |
3230 | va_list args; | |
3231 | static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); | |
3232 | ||
3233 | if ((gfp_mask & __GFP_NOWARN) || | |
3234 | !__ratelimit(&nopage_rs) || | |
3235 | ((gfp_mask & __GFP_DMA) && !has_managed_dma())) | |
3236 | return; | |
3237 | ||
3238 | va_start(args, fmt); | |
3239 | vaf.fmt = fmt; | |
3240 | vaf.va = &args; | |
3241 | pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl", | |
3242 | current->comm, &vaf, gfp_mask, &gfp_mask, | |
3243 | nodemask_pr_args(nodemask)); | |
3244 | va_end(args); | |
3245 | ||
3246 | cpuset_print_current_mems_allowed(); | |
3247 | pr_cont("\n"); | |
3248 | dump_stack(); | |
3249 | warn_alloc_show_mem(gfp_mask, nodemask); | |
3250 | } | |
3251 | ||
3252 | static inline struct page * | |
3253 | __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order, | |
3254 | unsigned int alloc_flags, | |
3255 | const struct alloc_context *ac) | |
3256 | { | |
3257 | struct page *page; | |
3258 | ||
3259 | page = get_page_from_freelist(gfp_mask, order, | |
3260 | alloc_flags|ALLOC_CPUSET, ac); | |
3261 | /* | |
3262 | * fallback to ignore cpuset restriction if our nodes | |
3263 | * are depleted | |
3264 | */ | |
3265 | if (!page) | |
3266 | page = get_page_from_freelist(gfp_mask, order, | |
3267 | alloc_flags, ac); | |
3268 | ||
3269 | return page; | |
3270 | } | |
3271 | ||
3272 | static inline struct page * | |
3273 | __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, | |
3274 | const struct alloc_context *ac, unsigned long *did_some_progress) | |
3275 | { | |
3276 | struct oom_control oc = { | |
3277 | .zonelist = ac->zonelist, | |
3278 | .nodemask = ac->nodemask, | |
3279 | .memcg = NULL, | |
3280 | .gfp_mask = gfp_mask, | |
3281 | .order = order, | |
3282 | }; | |
3283 | struct page *page; | |
3284 | ||
3285 | *did_some_progress = 0; | |
3286 | ||
3287 | /* | |
3288 | * Acquire the oom lock. If that fails, somebody else is | |
3289 | * making progress for us. | |
3290 | */ | |
3291 | if (!mutex_trylock(&oom_lock)) { | |
3292 | *did_some_progress = 1; | |
3293 | schedule_timeout_uninterruptible(1); | |
3294 | return NULL; | |
3295 | } | |
3296 | ||
3297 | /* | |
3298 | * Go through the zonelist yet one more time, keep very high watermark | |
3299 | * here, this is only to catch a parallel oom killing, we must fail if | |
3300 | * we're still under heavy pressure. But make sure that this reclaim | |
3301 | * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY | |
3302 | * allocation which will never fail due to oom_lock already held. | |
3303 | */ | |
3304 | page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) & | |
3305 | ~__GFP_DIRECT_RECLAIM, order, | |
3306 | ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac); | |
3307 | if (page) | |
3308 | goto out; | |
3309 | ||
3310 | /* Coredumps can quickly deplete all memory reserves */ | |
3311 | if (current->flags & PF_DUMPCORE) | |
3312 | goto out; | |
3313 | /* The OOM killer will not help higher order allocs */ | |
3314 | if (order > PAGE_ALLOC_COSTLY_ORDER) | |
3315 | goto out; | |
3316 | /* | |
3317 | * We have already exhausted all our reclaim opportunities without any | |
3318 | * success so it is time to admit defeat. We will skip the OOM killer | |
3319 | * because it is very likely that the caller has a more reasonable | |
3320 | * fallback than shooting a random task. | |
3321 | * | |
3322 | * The OOM killer may not free memory on a specific node. | |
3323 | */ | |
3324 | if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE)) | |
3325 | goto out; | |
3326 | /* The OOM killer does not needlessly kill tasks for lowmem */ | |
3327 | if (ac->highest_zoneidx < ZONE_NORMAL) | |
3328 | goto out; | |
3329 | if (pm_suspended_storage()) | |
3330 | goto out; | |
3331 | /* | |
3332 | * XXX: GFP_NOFS allocations should rather fail than rely on | |
3333 | * other request to make a forward progress. | |
3334 | * We are in an unfortunate situation where out_of_memory cannot | |
3335 | * do much for this context but let's try it to at least get | |
3336 | * access to memory reserved if the current task is killed (see | |
3337 | * out_of_memory). Once filesystems are ready to handle allocation | |
3338 | * failures more gracefully we should just bail out here. | |
3339 | */ | |
3340 | ||
3341 | /* Exhausted what can be done so it's blame time */ | |
3342 | if (out_of_memory(&oc) || | |
3343 | WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) { | |
3344 | *did_some_progress = 1; | |
3345 | ||
3346 | /* | |
3347 | * Help non-failing allocations by giving them access to memory | |
3348 | * reserves | |
3349 | */ | |
3350 | if (gfp_mask & __GFP_NOFAIL) | |
3351 | page = __alloc_pages_cpuset_fallback(gfp_mask, order, | |
3352 | ALLOC_NO_WATERMARKS, ac); | |
3353 | } | |
3354 | out: | |
3355 | mutex_unlock(&oom_lock); | |
3356 | return page; | |
3357 | } | |
3358 | ||
3359 | /* | |
3360 | * Maximum number of compaction retries with a progress before OOM | |
3361 | * killer is consider as the only way to move forward. | |
3362 | */ | |
3363 | #define MAX_COMPACT_RETRIES 16 | |
3364 | ||
3365 | #ifdef CONFIG_COMPACTION | |
3366 | /* Try memory compaction for high-order allocations before reclaim */ | |
3367 | static struct page * | |
3368 | __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, | |
3369 | unsigned int alloc_flags, const struct alloc_context *ac, | |
3370 | enum compact_priority prio, enum compact_result *compact_result) | |
3371 | { | |
3372 | struct page *page = NULL; | |
3373 | unsigned long pflags; | |
3374 | unsigned int noreclaim_flag; | |
3375 | ||
3376 | if (!order) | |
3377 | return NULL; | |
3378 | ||
3379 | psi_memstall_enter(&pflags); | |
3380 | delayacct_compact_start(); | |
3381 | noreclaim_flag = memalloc_noreclaim_save(); | |
3382 | ||
3383 | *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, | |
3384 | prio, &page); | |
3385 | ||
3386 | memalloc_noreclaim_restore(noreclaim_flag); | |
3387 | psi_memstall_leave(&pflags); | |
3388 | delayacct_compact_end(); | |
3389 | ||
3390 | if (*compact_result == COMPACT_SKIPPED) | |
3391 | return NULL; | |
3392 | /* | |
3393 | * At least in one zone compaction wasn't deferred or skipped, so let's | |
3394 | * count a compaction stall | |
3395 | */ | |
3396 | count_vm_event(COMPACTSTALL); | |
3397 | ||
3398 | /* Prep a captured page if available */ | |
3399 | if (page) | |
3400 | prep_new_page(page, order, gfp_mask, alloc_flags); | |
3401 | ||
3402 | /* Try get a page from the freelist if available */ | |
3403 | if (!page) | |
3404 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); | |
3405 | ||
3406 | if (page) { | |
3407 | struct zone *zone = page_zone(page); | |
3408 | ||
3409 | zone->compact_blockskip_flush = false; | |
3410 | compaction_defer_reset(zone, order, true); | |
3411 | count_vm_event(COMPACTSUCCESS); | |
3412 | return page; | |
3413 | } | |
3414 | ||
3415 | /* | |
3416 | * It's bad if compaction run occurs and fails. The most likely reason | |
3417 | * is that pages exist, but not enough to satisfy watermarks. | |
3418 | */ | |
3419 | count_vm_event(COMPACTFAIL); | |
3420 | ||
3421 | cond_resched(); | |
3422 | ||
3423 | return NULL; | |
3424 | } | |
3425 | ||
3426 | static inline bool | |
3427 | should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, | |
3428 | enum compact_result compact_result, | |
3429 | enum compact_priority *compact_priority, | |
3430 | int *compaction_retries) | |
3431 | { | |
3432 | int max_retries = MAX_COMPACT_RETRIES; | |
3433 | int min_priority; | |
3434 | bool ret = false; | |
3435 | int retries = *compaction_retries; | |
3436 | enum compact_priority priority = *compact_priority; | |
3437 | ||
3438 | if (!order) | |
3439 | return false; | |
3440 | ||
3441 | if (fatal_signal_pending(current)) | |
3442 | return false; | |
3443 | ||
3444 | /* | |
3445 | * Compaction was skipped due to a lack of free order-0 | |
3446 | * migration targets. Continue if reclaim can help. | |
3447 | */ | |
3448 | if (compact_result == COMPACT_SKIPPED) { | |
3449 | ret = compaction_zonelist_suitable(ac, order, alloc_flags); | |
3450 | goto out; | |
3451 | } | |
3452 | ||
3453 | /* | |
3454 | * Compaction managed to coalesce some page blocks, but the | |
3455 | * allocation failed presumably due to a race. Retry some. | |
3456 | */ | |
3457 | if (compact_result == COMPACT_SUCCESS) { | |
3458 | /* | |
3459 | * !costly requests are much more important than | |
3460 | * __GFP_RETRY_MAYFAIL costly ones because they are de | |
3461 | * facto nofail and invoke OOM killer to move on while | |
3462 | * costly can fail and users are ready to cope with | |
3463 | * that. 1/4 retries is rather arbitrary but we would | |
3464 | * need much more detailed feedback from compaction to | |
3465 | * make a better decision. | |
3466 | */ | |
3467 | if (order > PAGE_ALLOC_COSTLY_ORDER) | |
3468 | max_retries /= 4; | |
3469 | ||
3470 | if (++(*compaction_retries) <= max_retries) { | |
3471 | ret = true; | |
3472 | goto out; | |
3473 | } | |
3474 | } | |
3475 | ||
3476 | /* | |
3477 | * Compaction failed. Retry with increasing priority. | |
3478 | */ | |
3479 | min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? | |
3480 | MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; | |
3481 | ||
3482 | if (*compact_priority > min_priority) { | |
3483 | (*compact_priority)--; | |
3484 | *compaction_retries = 0; | |
3485 | ret = true; | |
3486 | } | |
3487 | out: | |
3488 | trace_compact_retry(order, priority, compact_result, retries, max_retries, ret); | |
3489 | return ret; | |
3490 | } | |
3491 | #else | |
3492 | static inline struct page * | |
3493 | __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, | |
3494 | unsigned int alloc_flags, const struct alloc_context *ac, | |
3495 | enum compact_priority prio, enum compact_result *compact_result) | |
3496 | { | |
3497 | *compact_result = COMPACT_SKIPPED; | |
3498 | return NULL; | |
3499 | } | |
3500 | ||
3501 | static inline bool | |
3502 | should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags, | |
3503 | enum compact_result compact_result, | |
3504 | enum compact_priority *compact_priority, | |
3505 | int *compaction_retries) | |
3506 | { | |
3507 | struct zone *zone; | |
3508 | struct zoneref *z; | |
3509 | ||
3510 | if (!order || order > PAGE_ALLOC_COSTLY_ORDER) | |
3511 | return false; | |
3512 | ||
3513 | /* | |
3514 | * There are setups with compaction disabled which would prefer to loop | |
3515 | * inside the allocator rather than hit the oom killer prematurely. | |
3516 | * Let's give them a good hope and keep retrying while the order-0 | |
3517 | * watermarks are OK. | |
3518 | */ | |
3519 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, | |
3520 | ac->highest_zoneidx, ac->nodemask) { | |
3521 | if (zone_watermark_ok(zone, 0, min_wmark_pages(zone), | |
3522 | ac->highest_zoneidx, alloc_flags)) | |
3523 | return true; | |
3524 | } | |
3525 | return false; | |
3526 | } | |
3527 | #endif /* CONFIG_COMPACTION */ | |
3528 | ||
3529 | #ifdef CONFIG_LOCKDEP | |
3530 | static struct lockdep_map __fs_reclaim_map = | |
3531 | STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map); | |
3532 | ||
3533 | static bool __need_reclaim(gfp_t gfp_mask) | |
3534 | { | |
3535 | /* no reclaim without waiting on it */ | |
3536 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) | |
3537 | return false; | |
3538 | ||
3539 | /* this guy won't enter reclaim */ | |
3540 | if (current->flags & PF_MEMALLOC) | |
3541 | return false; | |
3542 | ||
3543 | if (gfp_mask & __GFP_NOLOCKDEP) | |
3544 | return false; | |
3545 | ||
3546 | return true; | |
3547 | } | |
3548 | ||
3549 | void __fs_reclaim_acquire(unsigned long ip) | |
3550 | { | |
3551 | lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip); | |
3552 | } | |
3553 | ||
3554 | void __fs_reclaim_release(unsigned long ip) | |
3555 | { | |
3556 | lock_release(&__fs_reclaim_map, ip); | |
3557 | } | |
3558 | ||
3559 | void fs_reclaim_acquire(gfp_t gfp_mask) | |
3560 | { | |
3561 | gfp_mask = current_gfp_context(gfp_mask); | |
3562 | ||
3563 | if (__need_reclaim(gfp_mask)) { | |
3564 | if (gfp_mask & __GFP_FS) | |
3565 | __fs_reclaim_acquire(_RET_IP_); | |
3566 | ||
3567 | #ifdef CONFIG_MMU_NOTIFIER | |
3568 | lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); | |
3569 | lock_map_release(&__mmu_notifier_invalidate_range_start_map); | |
3570 | #endif | |
3571 | ||
3572 | } | |
3573 | } | |
3574 | EXPORT_SYMBOL_GPL(fs_reclaim_acquire); | |
3575 | ||
3576 | void fs_reclaim_release(gfp_t gfp_mask) | |
3577 | { | |
3578 | gfp_mask = current_gfp_context(gfp_mask); | |
3579 | ||
3580 | if (__need_reclaim(gfp_mask)) { | |
3581 | if (gfp_mask & __GFP_FS) | |
3582 | __fs_reclaim_release(_RET_IP_); | |
3583 | } | |
3584 | } | |
3585 | EXPORT_SYMBOL_GPL(fs_reclaim_release); | |
3586 | #endif | |
3587 | ||
3588 | /* | |
3589 | * Zonelists may change due to hotplug during allocation. Detect when zonelists | |
3590 | * have been rebuilt so allocation retries. Reader side does not lock and | |
3591 | * retries the allocation if zonelist changes. Writer side is protected by the | |
3592 | * embedded spin_lock. | |
3593 | */ | |
3594 | static DEFINE_SEQLOCK(zonelist_update_seq); | |
3595 | ||
3596 | static unsigned int zonelist_iter_begin(void) | |
3597 | { | |
3598 | if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) | |
3599 | return read_seqbegin(&zonelist_update_seq); | |
3600 | ||
3601 | return 0; | |
3602 | } | |
3603 | ||
3604 | static unsigned int check_retry_zonelist(unsigned int seq) | |
3605 | { | |
3606 | if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) | |
3607 | return read_seqretry(&zonelist_update_seq, seq); | |
3608 | ||
3609 | return seq; | |
3610 | } | |
3611 | ||
3612 | /* Perform direct synchronous page reclaim */ | |
3613 | static unsigned long | |
3614 | __perform_reclaim(gfp_t gfp_mask, unsigned int order, | |
3615 | const struct alloc_context *ac) | |
3616 | { | |
3617 | unsigned int noreclaim_flag; | |
3618 | unsigned long progress; | |
3619 | ||
3620 | cond_resched(); | |
3621 | ||
3622 | /* We now go into synchronous reclaim */ | |
3623 | cpuset_memory_pressure_bump(); | |
3624 | fs_reclaim_acquire(gfp_mask); | |
3625 | noreclaim_flag = memalloc_noreclaim_save(); | |
3626 | ||
3627 | progress = try_to_free_pages(ac->zonelist, order, gfp_mask, | |
3628 | ac->nodemask); | |
3629 | ||
3630 | memalloc_noreclaim_restore(noreclaim_flag); | |
3631 | fs_reclaim_release(gfp_mask); | |
3632 | ||
3633 | cond_resched(); | |
3634 | ||
3635 | return progress; | |
3636 | } | |
3637 | ||
3638 | /* The really slow allocator path where we enter direct reclaim */ | |
3639 | static inline struct page * | |
3640 | __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, | |
3641 | unsigned int alloc_flags, const struct alloc_context *ac, | |
3642 | unsigned long *did_some_progress) | |
3643 | { | |
3644 | struct page *page = NULL; | |
3645 | unsigned long pflags; | |
3646 | bool drained = false; | |
3647 | ||
3648 | psi_memstall_enter(&pflags); | |
3649 | *did_some_progress = __perform_reclaim(gfp_mask, order, ac); | |
3650 | if (unlikely(!(*did_some_progress))) | |
3651 | goto out; | |
3652 | ||
3653 | retry: | |
3654 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); | |
3655 | ||
3656 | /* | |
3657 | * If an allocation failed after direct reclaim, it could be because | |
3658 | * pages are pinned on the per-cpu lists or in high alloc reserves. | |
3659 | * Shrink them and try again | |
3660 | */ | |
3661 | if (!page && !drained) { | |
3662 | unreserve_highatomic_pageblock(ac, false); | |
3663 | drain_all_pages(NULL); | |
3664 | drained = true; | |
3665 | goto retry; | |
3666 | } | |
3667 | out: | |
3668 | psi_memstall_leave(&pflags); | |
3669 | ||
3670 | return page; | |
3671 | } | |
3672 | ||
3673 | static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask, | |
3674 | const struct alloc_context *ac) | |
3675 | { | |
3676 | struct zoneref *z; | |
3677 | struct zone *zone; | |
3678 | pg_data_t *last_pgdat = NULL; | |
3679 | enum zone_type highest_zoneidx = ac->highest_zoneidx; | |
3680 | ||
3681 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx, | |
3682 | ac->nodemask) { | |
3683 | if (!managed_zone(zone)) | |
3684 | continue; | |
3685 | if (last_pgdat != zone->zone_pgdat) { | |
3686 | wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx); | |
3687 | last_pgdat = zone->zone_pgdat; | |
3688 | } | |
3689 | } | |
3690 | } | |
3691 | ||
3692 | static inline unsigned int | |
3693 | gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) | |
3694 | { | |
3695 | unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; | |
3696 | ||
3697 | /* | |
3698 | * __GFP_HIGH is assumed to be the same as ALLOC_MIN_RESERVE | |
3699 | * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD | |
3700 | * to save two branches. | |
3701 | */ | |
3702 | BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_MIN_RESERVE); | |
3703 | BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD); | |
3704 | ||
3705 | /* | |
3706 | * The caller may dip into page reserves a bit more if the caller | |
3707 | * cannot run direct reclaim, or if the caller has realtime scheduling | |
3708 | * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will | |
3709 | * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). | |
3710 | */ | |
3711 | alloc_flags |= (__force int) | |
3712 | (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); | |
3713 | ||
3714 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { | |
3715 | /* | |
3716 | * Not worth trying to allocate harder for __GFP_NOMEMALLOC even | |
3717 | * if it can't schedule. | |
3718 | */ | |
3719 | if (!(gfp_mask & __GFP_NOMEMALLOC)) { | |
3720 | alloc_flags |= ALLOC_NON_BLOCK; | |
3721 | ||
3722 | if (order > 0) | |
3723 | alloc_flags |= ALLOC_HIGHATOMIC; | |
3724 | } | |
3725 | ||
3726 | /* | |
3727 | * Ignore cpuset mems for non-blocking __GFP_HIGH (probably | |
3728 | * GFP_ATOMIC) rather than fail, see the comment for | |
3729 | * cpuset_node_allowed(). | |
3730 | */ | |
3731 | if (alloc_flags & ALLOC_MIN_RESERVE) | |
3732 | alloc_flags &= ~ALLOC_CPUSET; | |
3733 | } else if (unlikely(rt_task(current)) && in_task()) | |
3734 | alloc_flags |= ALLOC_MIN_RESERVE; | |
3735 | ||
3736 | alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags); | |
3737 | ||
3738 | return alloc_flags; | |
3739 | } | |
3740 | ||
3741 | static bool oom_reserves_allowed(struct task_struct *tsk) | |
3742 | { | |
3743 | if (!tsk_is_oom_victim(tsk)) | |
3744 | return false; | |
3745 | ||
3746 | /* | |
3747 | * !MMU doesn't have oom reaper so give access to memory reserves | |
3748 | * only to the thread with TIF_MEMDIE set | |
3749 | */ | |
3750 | if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE)) | |
3751 | return false; | |
3752 | ||
3753 | return true; | |
3754 | } | |
3755 | ||
3756 | /* | |
3757 | * Distinguish requests which really need access to full memory | |
3758 | * reserves from oom victims which can live with a portion of it | |
3759 | */ | |
3760 | static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask) | |
3761 | { | |
3762 | if (unlikely(gfp_mask & __GFP_NOMEMALLOC)) | |
3763 | return 0; | |
3764 | if (gfp_mask & __GFP_MEMALLOC) | |
3765 | return ALLOC_NO_WATERMARKS; | |
3766 | if (in_serving_softirq() && (current->flags & PF_MEMALLOC)) | |
3767 | return ALLOC_NO_WATERMARKS; | |
3768 | if (!in_interrupt()) { | |
3769 | if (current->flags & PF_MEMALLOC) | |
3770 | return ALLOC_NO_WATERMARKS; | |
3771 | else if (oom_reserves_allowed(current)) | |
3772 | return ALLOC_OOM; | |
3773 | } | |
3774 | ||
3775 | return 0; | |
3776 | } | |
3777 | ||
3778 | bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) | |
3779 | { | |
3780 | return !!__gfp_pfmemalloc_flags(gfp_mask); | |
3781 | } | |
3782 | ||
3783 | /* | |
3784 | * Checks whether it makes sense to retry the reclaim to make a forward progress | |
3785 | * for the given allocation request. | |
3786 | * | |
3787 | * We give up when we either have tried MAX_RECLAIM_RETRIES in a row | |
3788 | * without success, or when we couldn't even meet the watermark if we | |
3789 | * reclaimed all remaining pages on the LRU lists. | |
3790 | * | |
3791 | * Returns true if a retry is viable or false to enter the oom path. | |
3792 | */ | |
3793 | static inline bool | |
3794 | should_reclaim_retry(gfp_t gfp_mask, unsigned order, | |
3795 | struct alloc_context *ac, int alloc_flags, | |
3796 | bool did_some_progress, int *no_progress_loops) | |
3797 | { | |
3798 | struct zone *zone; | |
3799 | struct zoneref *z; | |
3800 | bool ret = false; | |
3801 | ||
3802 | /* | |
3803 | * Costly allocations might have made a progress but this doesn't mean | |
3804 | * their order will become available due to high fragmentation so | |
3805 | * always increment the no progress counter for them | |
3806 | */ | |
3807 | if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) | |
3808 | *no_progress_loops = 0; | |
3809 | else | |
3810 | (*no_progress_loops)++; | |
3811 | ||
3812 | /* | |
3813 | * Make sure we converge to OOM if we cannot make any progress | |
3814 | * several times in the row. | |
3815 | */ | |
3816 | if (*no_progress_loops > MAX_RECLAIM_RETRIES) { | |
3817 | /* Before OOM, exhaust highatomic_reserve */ | |
3818 | return unreserve_highatomic_pageblock(ac, true); | |
3819 | } | |
3820 | ||
3821 | /* | |
3822 | * Keep reclaiming pages while there is a chance this will lead | |
3823 | * somewhere. If none of the target zones can satisfy our allocation | |
3824 | * request even if all reclaimable pages are considered then we are | |
3825 | * screwed and have to go OOM. | |
3826 | */ | |
3827 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, | |
3828 | ac->highest_zoneidx, ac->nodemask) { | |
3829 | unsigned long available; | |
3830 | unsigned long reclaimable; | |
3831 | unsigned long min_wmark = min_wmark_pages(zone); | |
3832 | bool wmark; | |
3833 | ||
3834 | available = reclaimable = zone_reclaimable_pages(zone); | |
3835 | available += zone_page_state_snapshot(zone, NR_FREE_PAGES); | |
3836 | ||
3837 | /* | |
3838 | * Would the allocation succeed if we reclaimed all | |
3839 | * reclaimable pages? | |
3840 | */ | |
3841 | wmark = __zone_watermark_ok(zone, order, min_wmark, | |
3842 | ac->highest_zoneidx, alloc_flags, available); | |
3843 | trace_reclaim_retry_zone(z, order, reclaimable, | |
3844 | available, min_wmark, *no_progress_loops, wmark); | |
3845 | if (wmark) { | |
3846 | ret = true; | |
3847 | break; | |
3848 | } | |
3849 | } | |
3850 | ||
3851 | /* | |
3852 | * Memory allocation/reclaim might be called from a WQ context and the | |
3853 | * current implementation of the WQ concurrency control doesn't | |
3854 | * recognize that a particular WQ is congested if the worker thread is | |
3855 | * looping without ever sleeping. Therefore we have to do a short sleep | |
3856 | * here rather than calling cond_resched(). | |
3857 | */ | |
3858 | if (current->flags & PF_WQ_WORKER) | |
3859 | schedule_timeout_uninterruptible(1); | |
3860 | else | |
3861 | cond_resched(); | |
3862 | return ret; | |
3863 | } | |
3864 | ||
3865 | static inline bool | |
3866 | check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) | |
3867 | { | |
3868 | /* | |
3869 | * It's possible that cpuset's mems_allowed and the nodemask from | |
3870 | * mempolicy don't intersect. This should be normally dealt with by | |
3871 | * policy_nodemask(), but it's possible to race with cpuset update in | |
3872 | * such a way the check therein was true, and then it became false | |
3873 | * before we got our cpuset_mems_cookie here. | |
3874 | * This assumes that for all allocations, ac->nodemask can come only | |
3875 | * from MPOL_BIND mempolicy (whose documented semantics is to be ignored | |
3876 | * when it does not intersect with the cpuset restrictions) or the | |
3877 | * caller can deal with a violated nodemask. | |
3878 | */ | |
3879 | if (cpusets_enabled() && ac->nodemask && | |
3880 | !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) { | |
3881 | ac->nodemask = NULL; | |
3882 | return true; | |
3883 | } | |
3884 | ||
3885 | /* | |
3886 | * When updating a task's mems_allowed or mempolicy nodemask, it is | |
3887 | * possible to race with parallel threads in such a way that our | |
3888 | * allocation can fail while the mask is being updated. If we are about | |
3889 | * to fail, check if the cpuset changed during allocation and if so, | |
3890 | * retry. | |
3891 | */ | |
3892 | if (read_mems_allowed_retry(cpuset_mems_cookie)) | |
3893 | return true; | |
3894 | ||
3895 | return false; | |
3896 | } | |
3897 | ||
3898 | static inline struct page * | |
3899 | __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, | |
3900 | struct alloc_context *ac) | |
3901 | { | |
3902 | bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; | |
3903 | const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; | |
3904 | struct page *page = NULL; | |
3905 | unsigned int alloc_flags; | |
3906 | unsigned long did_some_progress; | |
3907 | enum compact_priority compact_priority; | |
3908 | enum compact_result compact_result; | |
3909 | int compaction_retries; | |
3910 | int no_progress_loops; | |
3911 | unsigned int cpuset_mems_cookie; | |
3912 | unsigned int zonelist_iter_cookie; | |
3913 | int reserve_flags; | |
3914 | ||
3915 | restart: | |
3916 | compaction_retries = 0; | |
3917 | no_progress_loops = 0; | |
3918 | compact_priority = DEF_COMPACT_PRIORITY; | |
3919 | cpuset_mems_cookie = read_mems_allowed_begin(); | |
3920 | zonelist_iter_cookie = zonelist_iter_begin(); | |
3921 | ||
3922 | /* | |
3923 | * The fast path uses conservative alloc_flags to succeed only until | |
3924 | * kswapd needs to be woken up, and to avoid the cost of setting up | |
3925 | * alloc_flags precisely. So we do that now. | |
3926 | */ | |
3927 | alloc_flags = gfp_to_alloc_flags(gfp_mask, order); | |
3928 | ||
3929 | /* | |
3930 | * We need to recalculate the starting point for the zonelist iterator | |
3931 | * because we might have used different nodemask in the fast path, or | |
3932 | * there was a cpuset modification and we are retrying - otherwise we | |
3933 | * could end up iterating over non-eligible zones endlessly. | |
3934 | */ | |
3935 | ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, | |
3936 | ac->highest_zoneidx, ac->nodemask); | |
3937 | if (!ac->preferred_zoneref->zone) | |
3938 | goto nopage; | |
3939 | ||
3940 | /* | |
3941 | * Check for insane configurations where the cpuset doesn't contain | |
3942 | * any suitable zone to satisfy the request - e.g. non-movable | |
3943 | * GFP_HIGHUSER allocations from MOVABLE nodes only. | |
3944 | */ | |
3945 | if (cpusets_insane_config() && (gfp_mask & __GFP_HARDWALL)) { | |
3946 | struct zoneref *z = first_zones_zonelist(ac->zonelist, | |
3947 | ac->highest_zoneidx, | |
3948 | &cpuset_current_mems_allowed); | |
3949 | if (!z->zone) | |
3950 | goto nopage; | |
3951 | } | |
3952 | ||
3953 | if (alloc_flags & ALLOC_KSWAPD) | |
3954 | wake_all_kswapds(order, gfp_mask, ac); | |
3955 | ||
3956 | /* | |
3957 | * The adjusted alloc_flags might result in immediate success, so try | |
3958 | * that first | |
3959 | */ | |
3960 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); | |
3961 | if (page) | |
3962 | goto got_pg; | |
3963 | ||
3964 | /* | |
3965 | * For costly allocations, try direct compaction first, as it's likely | |
3966 | * that we have enough base pages and don't need to reclaim. For non- | |
3967 | * movable high-order allocations, do that as well, as compaction will | |
3968 | * try prevent permanent fragmentation by migrating from blocks of the | |
3969 | * same migratetype. | |
3970 | * Don't try this for allocations that are allowed to ignore | |
3971 | * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen. | |
3972 | */ | |
3973 | if (can_direct_reclaim && | |
3974 | (costly_order || | |
3975 | (order > 0 && ac->migratetype != MIGRATE_MOVABLE)) | |
3976 | && !gfp_pfmemalloc_allowed(gfp_mask)) { | |
3977 | page = __alloc_pages_direct_compact(gfp_mask, order, | |
3978 | alloc_flags, ac, | |
3979 | INIT_COMPACT_PRIORITY, | |
3980 | &compact_result); | |
3981 | if (page) | |
3982 | goto got_pg; | |
3983 | ||
3984 | /* | |
3985 | * Checks for costly allocations with __GFP_NORETRY, which | |
3986 | * includes some THP page fault allocations | |
3987 | */ | |
3988 | if (costly_order && (gfp_mask & __GFP_NORETRY)) { | |
3989 | /* | |
3990 | * If allocating entire pageblock(s) and compaction | |
3991 | * failed because all zones are below low watermarks | |
3992 | * or is prohibited because it recently failed at this | |
3993 | * order, fail immediately unless the allocator has | |
3994 | * requested compaction and reclaim retry. | |
3995 | * | |
3996 | * Reclaim is | |
3997 | * - potentially very expensive because zones are far | |
3998 | * below their low watermarks or this is part of very | |
3999 | * bursty high order allocations, | |
4000 | * - not guaranteed to help because isolate_freepages() | |
4001 | * may not iterate over freed pages as part of its | |
4002 | * linear scan, and | |
4003 | * - unlikely to make entire pageblocks free on its | |
4004 | * own. | |
4005 | */ | |
4006 | if (compact_result == COMPACT_SKIPPED || | |
4007 | compact_result == COMPACT_DEFERRED) | |
4008 | goto nopage; | |
4009 | ||
4010 | /* | |
4011 | * Looks like reclaim/compaction is worth trying, but | |
4012 | * sync compaction could be very expensive, so keep | |
4013 | * using async compaction. | |
4014 | */ | |
4015 | compact_priority = INIT_COMPACT_PRIORITY; | |
4016 | } | |
4017 | } | |
4018 | ||
4019 | retry: | |
4020 | /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ | |
4021 | if (alloc_flags & ALLOC_KSWAPD) | |
4022 | wake_all_kswapds(order, gfp_mask, ac); | |
4023 | ||
4024 | reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); | |
4025 | if (reserve_flags) | |
4026 | alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | | |
4027 | (alloc_flags & ALLOC_KSWAPD); | |
4028 | ||
4029 | /* | |
4030 | * Reset the nodemask and zonelist iterators if memory policies can be | |
4031 | * ignored. These allocations are high priority and system rather than | |
4032 | * user oriented. | |
4033 | */ | |
4034 | if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) { | |
4035 | ac->nodemask = NULL; | |
4036 | ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, | |
4037 | ac->highest_zoneidx, ac->nodemask); | |
4038 | } | |
4039 | ||
4040 | /* Attempt with potentially adjusted zonelist and alloc_flags */ | |
4041 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); | |
4042 | if (page) | |
4043 | goto got_pg; | |
4044 | ||
4045 | /* Caller is not willing to reclaim, we can't balance anything */ | |
4046 | if (!can_direct_reclaim) | |
4047 | goto nopage; | |
4048 | ||
4049 | /* Avoid recursion of direct reclaim */ | |
4050 | if (current->flags & PF_MEMALLOC) | |
4051 | goto nopage; | |
4052 | ||
4053 | /* Try direct reclaim and then allocating */ | |
4054 | page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, | |
4055 | &did_some_progress); | |
4056 | if (page) | |
4057 | goto got_pg; | |
4058 | ||
4059 | /* Try direct compaction and then allocating */ | |
4060 | page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, | |
4061 | compact_priority, &compact_result); | |
4062 | if (page) | |
4063 | goto got_pg; | |
4064 | ||
4065 | /* Do not loop if specifically requested */ | |
4066 | if (gfp_mask & __GFP_NORETRY) | |
4067 | goto nopage; | |
4068 | ||
4069 | /* | |
4070 | * Do not retry costly high order allocations unless they are | |
4071 | * __GFP_RETRY_MAYFAIL | |
4072 | */ | |
4073 | if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL)) | |
4074 | goto nopage; | |
4075 | ||
4076 | if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, | |
4077 | did_some_progress > 0, &no_progress_loops)) | |
4078 | goto retry; | |
4079 | ||
4080 | /* | |
4081 | * It doesn't make any sense to retry for the compaction if the order-0 | |
4082 | * reclaim is not able to make any progress because the current | |
4083 | * implementation of the compaction depends on the sufficient amount | |
4084 | * of free memory (see __compaction_suitable) | |
4085 | */ | |
4086 | if (did_some_progress > 0 && | |
4087 | should_compact_retry(ac, order, alloc_flags, | |
4088 | compact_result, &compact_priority, | |
4089 | &compaction_retries)) | |
4090 | goto retry; | |
4091 | ||
4092 | ||
4093 | /* | |
4094 | * Deal with possible cpuset update races or zonelist updates to avoid | |
4095 | * a unnecessary OOM kill. | |
4096 | */ | |
4097 | if (check_retry_cpuset(cpuset_mems_cookie, ac) || | |
4098 | check_retry_zonelist(zonelist_iter_cookie)) | |
4099 | goto restart; | |
4100 | ||
4101 | /* Reclaim has failed us, start killing things */ | |
4102 | page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); | |
4103 | if (page) | |
4104 | goto got_pg; | |
4105 | ||
4106 | /* Avoid allocations with no watermarks from looping endlessly */ | |
4107 | if (tsk_is_oom_victim(current) && | |
4108 | (alloc_flags & ALLOC_OOM || | |
4109 | (gfp_mask & __GFP_NOMEMALLOC))) | |
4110 | goto nopage; | |
4111 | ||
4112 | /* Retry as long as the OOM killer is making progress */ | |
4113 | if (did_some_progress) { | |
4114 | no_progress_loops = 0; | |
4115 | goto retry; | |
4116 | } | |
4117 | ||
4118 | nopage: | |
4119 | /* | |
4120 | * Deal with possible cpuset update races or zonelist updates to avoid | |
4121 | * a unnecessary OOM kill. | |
4122 | */ | |
4123 | if (check_retry_cpuset(cpuset_mems_cookie, ac) || | |
4124 | check_retry_zonelist(zonelist_iter_cookie)) | |
4125 | goto restart; | |
4126 | ||
4127 | /* | |
4128 | * Make sure that __GFP_NOFAIL request doesn't leak out and make sure | |
4129 | * we always retry | |
4130 | */ | |
4131 | if (gfp_mask & __GFP_NOFAIL) { | |
4132 | /* | |
4133 | * All existing users of the __GFP_NOFAIL are blockable, so warn | |
4134 | * of any new users that actually require GFP_NOWAIT | |
4135 | */ | |
4136 | if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask)) | |
4137 | goto fail; | |
4138 | ||
4139 | /* | |
4140 | * PF_MEMALLOC request from this context is rather bizarre | |
4141 | * because we cannot reclaim anything and only can loop waiting | |
4142 | * for somebody to do a work for us | |
4143 | */ | |
4144 | WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask); | |
4145 | ||
4146 | /* | |
4147 | * non failing costly orders are a hard requirement which we | |
4148 | * are not prepared for much so let's warn about these users | |
4149 | * so that we can identify them and convert them to something | |
4150 | * else. | |
4151 | */ | |
4152 | WARN_ON_ONCE_GFP(costly_order, gfp_mask); | |
4153 | ||
4154 | /* | |
4155 | * Help non-failing allocations by giving some access to memory | |
4156 | * reserves normally used for high priority non-blocking | |
4157 | * allocations but do not use ALLOC_NO_WATERMARKS because this | |
4158 | * could deplete whole memory reserves which would just make | |
4159 | * the situation worse. | |
4160 | */ | |
4161 | page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac); | |
4162 | if (page) | |
4163 | goto got_pg; | |
4164 | ||
4165 | cond_resched(); | |
4166 | goto retry; | |
4167 | } | |
4168 | fail: | |
4169 | warn_alloc(gfp_mask, ac->nodemask, | |
4170 | "page allocation failure: order:%u", order); | |
4171 | got_pg: | |
4172 | return page; | |
4173 | } | |
4174 | ||
4175 | static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, | |
4176 | int preferred_nid, nodemask_t *nodemask, | |
4177 | struct alloc_context *ac, gfp_t *alloc_gfp, | |
4178 | unsigned int *alloc_flags) | |
4179 | { | |
4180 | ac->highest_zoneidx = gfp_zone(gfp_mask); | |
4181 | ac->zonelist = node_zonelist(preferred_nid, gfp_mask); | |
4182 | ac->nodemask = nodemask; | |
4183 | ac->migratetype = gfp_migratetype(gfp_mask); | |
4184 | ||
4185 | if (cpusets_enabled()) { | |
4186 | *alloc_gfp |= __GFP_HARDWALL; | |
4187 | /* | |
4188 | * When we are in the interrupt context, it is irrelevant | |
4189 | * to the current task context. It means that any node ok. | |
4190 | */ | |
4191 | if (in_task() && !ac->nodemask) | |
4192 | ac->nodemask = &cpuset_current_mems_allowed; | |
4193 | else | |
4194 | *alloc_flags |= ALLOC_CPUSET; | |
4195 | } | |
4196 | ||
4197 | might_alloc(gfp_mask); | |
4198 | ||
4199 | if (should_fail_alloc_page(gfp_mask, order)) | |
4200 | return false; | |
4201 | ||
4202 | *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags); | |
4203 | ||
4204 | /* Dirty zone balancing only done in the fast path */ | |
4205 | ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE); | |
4206 | ||
4207 | /* | |
4208 | * The preferred zone is used for statistics but crucially it is | |
4209 | * also used as the starting point for the zonelist iterator. It | |
4210 | * may get reset for allocations that ignore memory policies. | |
4211 | */ | |
4212 | ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, | |
4213 | ac->highest_zoneidx, ac->nodemask); | |
4214 | ||
4215 | return true; | |
4216 | } | |
4217 | ||
4218 | /* | |
4219 | * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array | |
4220 | * @gfp: GFP flags for the allocation | |
4221 | * @preferred_nid: The preferred NUMA node ID to allocate from | |
4222 | * @nodemask: Set of nodes to allocate from, may be NULL | |
4223 | * @nr_pages: The number of pages desired on the list or array | |
4224 | * @page_list: Optional list to store the allocated pages | |
4225 | * @page_array: Optional array to store the pages | |
4226 | * | |
4227 | * This is a batched version of the page allocator that attempts to | |
4228 | * allocate nr_pages quickly. Pages are added to page_list if page_list | |
4229 | * is not NULL, otherwise it is assumed that the page_array is valid. | |
4230 | * | |
4231 | * For lists, nr_pages is the number of pages that should be allocated. | |
4232 | * | |
4233 | * For arrays, only NULL elements are populated with pages and nr_pages | |
4234 | * is the maximum number of pages that will be stored in the array. | |
4235 | * | |
4236 | * Returns the number of pages on the list or array. | |
4237 | */ | |
4238 | unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, | |
4239 | nodemask_t *nodemask, int nr_pages, | |
4240 | struct list_head *page_list, | |
4241 | struct page **page_array) | |
4242 | { | |
4243 | struct page *page; | |
4244 | unsigned long __maybe_unused UP_flags; | |
4245 | struct zone *zone; | |
4246 | struct zoneref *z; | |
4247 | struct per_cpu_pages *pcp; | |
4248 | struct list_head *pcp_list; | |
4249 | struct alloc_context ac; | |
4250 | gfp_t alloc_gfp; | |
4251 | unsigned int alloc_flags = ALLOC_WMARK_LOW; | |
4252 | int nr_populated = 0, nr_account = 0; | |
4253 | ||
4254 | /* | |
4255 | * Skip populated array elements to determine if any pages need | |
4256 | * to be allocated before disabling IRQs. | |
4257 | */ | |
4258 | while (page_array && nr_populated < nr_pages && page_array[nr_populated]) | |
4259 | nr_populated++; | |
4260 | ||
4261 | /* No pages requested? */ | |
4262 | if (unlikely(nr_pages <= 0)) | |
4263 | goto out; | |
4264 | ||
4265 | /* Already populated array? */ | |
4266 | if (unlikely(page_array && nr_pages - nr_populated == 0)) | |
4267 | goto out; | |
4268 | ||
4269 | /* Bulk allocator does not support memcg accounting. */ | |
4270 | if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT)) | |
4271 | goto failed; | |
4272 | ||
4273 | /* Use the single page allocator for one page. */ | |
4274 | if (nr_pages - nr_populated == 1) | |
4275 | goto failed; | |
4276 | ||
4277 | #ifdef CONFIG_PAGE_OWNER | |
4278 | /* | |
4279 | * PAGE_OWNER may recurse into the allocator to allocate space to | |
4280 | * save the stack with pagesets.lock held. Releasing/reacquiring | |
4281 | * removes much of the performance benefit of bulk allocation so | |
4282 | * force the caller to allocate one page at a time as it'll have | |
4283 | * similar performance to added complexity to the bulk allocator. | |
4284 | */ | |
4285 | if (static_branch_unlikely(&page_owner_inited)) | |
4286 | goto failed; | |
4287 | #endif | |
4288 | ||
4289 | /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ | |
4290 | gfp &= gfp_allowed_mask; | |
4291 | alloc_gfp = gfp; | |
4292 | if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) | |
4293 | goto out; | |
4294 | gfp = alloc_gfp; | |
4295 | ||
4296 | /* Find an allowed local zone that meets the low watermark. */ | |
4297 | for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) { | |
4298 | unsigned long mark; | |
4299 | ||
4300 | if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && | |
4301 | !__cpuset_zone_allowed(zone, gfp)) { | |
4302 | continue; | |
4303 | } | |
4304 | ||
4305 | if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone && | |
4306 | zone_to_nid(zone) != zone_to_nid(ac.preferred_zoneref->zone)) { | |
4307 | goto failed; | |
4308 | } | |
4309 | ||
4310 | mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages; | |
4311 | if (zone_watermark_fast(zone, 0, mark, | |
4312 | zonelist_zone_idx(ac.preferred_zoneref), | |
4313 | alloc_flags, gfp)) { | |
4314 | break; | |
4315 | } | |
4316 | } | |
4317 | ||
4318 | /* | |
4319 | * If there are no allowed local zones that meets the watermarks then | |
4320 | * try to allocate a single page and reclaim if necessary. | |
4321 | */ | |
4322 | if (unlikely(!zone)) | |
4323 | goto failed; | |
4324 | ||
4325 | /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ | |
4326 | pcp_trylock_prepare(UP_flags); | |
4327 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); | |
4328 | if (!pcp) | |
4329 | goto failed_irq; | |
4330 | ||
4331 | /* Attempt the batch allocation */ | |
4332 | pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)]; | |
4333 | while (nr_populated < nr_pages) { | |
4334 | ||
4335 | /* Skip existing pages */ | |
4336 | if (page_array && page_array[nr_populated]) { | |
4337 | nr_populated++; | |
4338 | continue; | |
4339 | } | |
4340 | ||
4341 | page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags, | |
4342 | pcp, pcp_list); | |
4343 | if (unlikely(!page)) { | |
4344 | /* Try and allocate at least one page */ | |
4345 | if (!nr_account) { | |
4346 | pcp_spin_unlock(pcp); | |
4347 | goto failed_irq; | |
4348 | } | |
4349 | break; | |
4350 | } | |
4351 | nr_account++; | |
4352 | ||
4353 | prep_new_page(page, 0, gfp, 0); | |
4354 | if (page_list) | |
4355 | list_add(&page->lru, page_list); | |
4356 | else | |
4357 | page_array[nr_populated] = page; | |
4358 | nr_populated++; | |
4359 | } | |
4360 | ||
4361 | pcp_spin_unlock(pcp); | |
4362 | pcp_trylock_finish(UP_flags); | |
4363 | ||
4364 | __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account); | |
4365 | zone_statistics(ac.preferred_zoneref->zone, zone, nr_account); | |
4366 | ||
4367 | out: | |
4368 | return nr_populated; | |
4369 | ||
4370 | failed_irq: | |
4371 | pcp_trylock_finish(UP_flags); | |
4372 | ||
4373 | failed: | |
4374 | page = __alloc_pages(gfp, 0, preferred_nid, nodemask); | |
4375 | if (page) { | |
4376 | if (page_list) | |
4377 | list_add(&page->lru, page_list); | |
4378 | else | |
4379 | page_array[nr_populated] = page; | |
4380 | nr_populated++; | |
4381 | } | |
4382 | ||
4383 | goto out; | |
4384 | } | |
4385 | EXPORT_SYMBOL_GPL(__alloc_pages_bulk); | |
4386 | ||
4387 | /* | |
4388 | * This is the 'heart' of the zoned buddy allocator. | |
4389 | */ | |
4390 | struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, | |
4391 | nodemask_t *nodemask) | |
4392 | { | |
4393 | struct page *page; | |
4394 | unsigned int alloc_flags = ALLOC_WMARK_LOW; | |
4395 | gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */ | |
4396 | struct alloc_context ac = { }; | |
4397 | ||
4398 | /* | |
4399 | * There are several places where we assume that the order value is sane | |
4400 | * so bail out early if the request is out of bound. | |
4401 | */ | |
4402 | if (WARN_ON_ONCE_GFP(order > MAX_ORDER, gfp)) | |
4403 | return NULL; | |
4404 | ||
4405 | gfp &= gfp_allowed_mask; | |
4406 | /* | |
4407 | * Apply scoped allocation constraints. This is mainly about GFP_NOFS | |
4408 | * resp. GFP_NOIO which has to be inherited for all allocation requests | |
4409 | * from a particular context which has been marked by | |
4410 | * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures | |
4411 | * movable zones are not used during allocation. | |
4412 | */ | |
4413 | gfp = current_gfp_context(gfp); | |
4414 | alloc_gfp = gfp; | |
4415 | if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac, | |
4416 | &alloc_gfp, &alloc_flags)) | |
4417 | return NULL; | |
4418 | ||
4419 | /* | |
4420 | * Forbid the first pass from falling back to types that fragment | |
4421 | * memory until all local zones are considered. | |
4422 | */ | |
4423 | alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp); | |
4424 | ||
4425 | /* First allocation attempt */ | |
4426 | page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac); | |
4427 | if (likely(page)) | |
4428 | goto out; | |
4429 | ||
4430 | alloc_gfp = gfp; | |
4431 | ac.spread_dirty_pages = false; | |
4432 | ||
4433 | /* | |
4434 | * Restore the original nodemask if it was potentially replaced with | |
4435 | * &cpuset_current_mems_allowed to optimize the fast-path attempt. | |
4436 | */ | |
4437 | ac.nodemask = nodemask; | |
4438 | ||
4439 | page = __alloc_pages_slowpath(alloc_gfp, order, &ac); | |
4440 | ||
4441 | out: | |
4442 | if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page && | |
4443 | unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) { | |
4444 | __free_pages(page, order); | |
4445 | page = NULL; | |
4446 | } | |
4447 | ||
4448 | trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype); | |
4449 | kmsan_alloc_page(page, order, alloc_gfp); | |
4450 | ||
4451 | return page; | |
4452 | } | |
4453 | EXPORT_SYMBOL(__alloc_pages); | |
4454 | ||
4455 | struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid, | |
4456 | nodemask_t *nodemask) | |
4457 | { | |
4458 | struct page *page = __alloc_pages(gfp | __GFP_COMP, order, | |
4459 | preferred_nid, nodemask); | |
4460 | struct folio *folio = (struct folio *)page; | |
4461 | ||
4462 | if (folio && order > 1) | |
4463 | folio_prep_large_rmappable(folio); | |
4464 | return folio; | |
4465 | } | |
4466 | EXPORT_SYMBOL(__folio_alloc); | |
4467 | ||
4468 | /* | |
4469 | * Common helper functions. Never use with __GFP_HIGHMEM because the returned | |
4470 | * address cannot represent highmem pages. Use alloc_pages and then kmap if | |
4471 | * you need to access high mem. | |
4472 | */ | |
4473 | unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order) | |
4474 | { | |
4475 | struct page *page; | |
4476 | ||
4477 | page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order); | |
4478 | if (!page) | |
4479 | return 0; | |
4480 | return (unsigned long) page_address(page); | |
4481 | } | |
4482 | EXPORT_SYMBOL(__get_free_pages); | |
4483 | ||
4484 | unsigned long get_zeroed_page(gfp_t gfp_mask) | |
4485 | { | |
4486 | return __get_free_page(gfp_mask | __GFP_ZERO); | |
4487 | } | |
4488 | EXPORT_SYMBOL(get_zeroed_page); | |
4489 | ||
4490 | /** | |
4491 | * __free_pages - Free pages allocated with alloc_pages(). | |
4492 | * @page: The page pointer returned from alloc_pages(). | |
4493 | * @order: The order of the allocation. | |
4494 | * | |
4495 | * This function can free multi-page allocations that are not compound | |
4496 | * pages. It does not check that the @order passed in matches that of | |
4497 | * the allocation, so it is easy to leak memory. Freeing more memory | |
4498 | * than was allocated will probably emit a warning. | |
4499 | * | |
4500 | * If the last reference to this page is speculative, it will be released | |
4501 | * by put_page() which only frees the first page of a non-compound | |
4502 | * allocation. To prevent the remaining pages from being leaked, we free | |
4503 | * the subsequent pages here. If you want to use the page's reference | |
4504 | * count to decide when to free the allocation, you should allocate a | |
4505 | * compound page, and use put_page() instead of __free_pages(). | |
4506 | * | |
4507 | * Context: May be called in interrupt context or while holding a normal | |
4508 | * spinlock, but not in NMI context or while holding a raw spinlock. | |
4509 | */ | |
4510 | void __free_pages(struct page *page, unsigned int order) | |
4511 | { | |
4512 | /* get PageHead before we drop reference */ | |
4513 | int head = PageHead(page); | |
4514 | ||
4515 | if (put_page_testzero(page)) | |
4516 | free_the_page(page, order); | |
4517 | else if (!head) | |
4518 | while (order-- > 0) | |
4519 | free_the_page(page + (1 << order), order); | |
4520 | } | |
4521 | EXPORT_SYMBOL(__free_pages); | |
4522 | ||
4523 | void free_pages(unsigned long addr, unsigned int order) | |
4524 | { | |
4525 | if (addr != 0) { | |
4526 | VM_BUG_ON(!virt_addr_valid((void *)addr)); | |
4527 | __free_pages(virt_to_page((void *)addr), order); | |
4528 | } | |
4529 | } | |
4530 | ||
4531 | EXPORT_SYMBOL(free_pages); | |
4532 | ||
4533 | /* | |
4534 | * Page Fragment: | |
4535 | * An arbitrary-length arbitrary-offset area of memory which resides | |
4536 | * within a 0 or higher order page. Multiple fragments within that page | |
4537 | * are individually refcounted, in the page's reference counter. | |
4538 | * | |
4539 | * The page_frag functions below provide a simple allocation framework for | |
4540 | * page fragments. This is used by the network stack and network device | |
4541 | * drivers to provide a backing region of memory for use as either an | |
4542 | * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. | |
4543 | */ | |
4544 | static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, | |
4545 | gfp_t gfp_mask) | |
4546 | { | |
4547 | struct page *page = NULL; | |
4548 | gfp_t gfp = gfp_mask; | |
4549 | ||
4550 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) | |
4551 | gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | | |
4552 | __GFP_NOMEMALLOC; | |
4553 | page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, | |
4554 | PAGE_FRAG_CACHE_MAX_ORDER); | |
4555 | nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; | |
4556 | #endif | |
4557 | if (unlikely(!page)) | |
4558 | page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); | |
4559 | ||
4560 | nc->va = page ? page_address(page) : NULL; | |
4561 | ||
4562 | return page; | |
4563 | } | |
4564 | ||
4565 | void __page_frag_cache_drain(struct page *page, unsigned int count) | |
4566 | { | |
4567 | VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); | |
4568 | ||
4569 | if (page_ref_sub_and_test(page, count)) | |
4570 | free_the_page(page, compound_order(page)); | |
4571 | } | |
4572 | EXPORT_SYMBOL(__page_frag_cache_drain); | |
4573 | ||
4574 | void *page_frag_alloc_align(struct page_frag_cache *nc, | |
4575 | unsigned int fragsz, gfp_t gfp_mask, | |
4576 | unsigned int align_mask) | |
4577 | { | |
4578 | unsigned int size = PAGE_SIZE; | |
4579 | struct page *page; | |
4580 | int offset; | |
4581 | ||
4582 | if (unlikely(!nc->va)) { | |
4583 | refill: | |
4584 | page = __page_frag_cache_refill(nc, gfp_mask); | |
4585 | if (!page) | |
4586 | return NULL; | |
4587 | ||
4588 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) | |
4589 | /* if size can vary use size else just use PAGE_SIZE */ | |
4590 | size = nc->size; | |
4591 | #endif | |
4592 | /* Even if we own the page, we do not use atomic_set(). | |
4593 | * This would break get_page_unless_zero() users. | |
4594 | */ | |
4595 | page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); | |
4596 | ||
4597 | /* reset page count bias and offset to start of new frag */ | |
4598 | nc->pfmemalloc = page_is_pfmemalloc(page); | |
4599 | nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; | |
4600 | nc->offset = size; | |
4601 | } | |
4602 | ||
4603 | offset = nc->offset - fragsz; | |
4604 | if (unlikely(offset < 0)) { | |
4605 | page = virt_to_page(nc->va); | |
4606 | ||
4607 | if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) | |
4608 | goto refill; | |
4609 | ||
4610 | if (unlikely(nc->pfmemalloc)) { | |
4611 | free_the_page(page, compound_order(page)); | |
4612 | goto refill; | |
4613 | } | |
4614 | ||
4615 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) | |
4616 | /* if size can vary use size else just use PAGE_SIZE */ | |
4617 | size = nc->size; | |
4618 | #endif | |
4619 | /* OK, page count is 0, we can safely set it */ | |
4620 | set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); | |
4621 | ||
4622 | /* reset page count bias and offset to start of new frag */ | |
4623 | nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; | |
4624 | offset = size - fragsz; | |
4625 | if (unlikely(offset < 0)) { | |
4626 | /* | |
4627 | * The caller is trying to allocate a fragment | |
4628 | * with fragsz > PAGE_SIZE but the cache isn't big | |
4629 | * enough to satisfy the request, this may | |
4630 | * happen in low memory conditions. | |
4631 | * We don't release the cache page because | |
4632 | * it could make memory pressure worse | |
4633 | * so we simply return NULL here. | |
4634 | */ | |
4635 | return NULL; | |
4636 | } | |
4637 | } | |
4638 | ||
4639 | nc->pagecnt_bias--; | |
4640 | offset &= align_mask; | |
4641 | nc->offset = offset; | |
4642 | ||
4643 | return nc->va + offset; | |
4644 | } | |
4645 | EXPORT_SYMBOL(page_frag_alloc_align); | |
4646 | ||
4647 | /* | |
4648 | * Frees a page fragment allocated out of either a compound or order 0 page. | |
4649 | */ | |
4650 | void page_frag_free(void *addr) | |
4651 | { | |
4652 | struct page *page = virt_to_head_page(addr); | |
4653 | ||
4654 | if (unlikely(put_page_testzero(page))) | |
4655 | free_the_page(page, compound_order(page)); | |
4656 | } | |
4657 | EXPORT_SYMBOL(page_frag_free); | |
4658 | ||
4659 | static void *make_alloc_exact(unsigned long addr, unsigned int order, | |
4660 | size_t size) | |
4661 | { | |
4662 | if (addr) { | |
4663 | unsigned long nr = DIV_ROUND_UP(size, PAGE_SIZE); | |
4664 | struct page *page = virt_to_page((void *)addr); | |
4665 | struct page *last = page + nr; | |
4666 | ||
4667 | split_page_owner(page, 1 << order); | |
4668 | split_page_memcg(page, 1 << order); | |
4669 | while (page < --last) | |
4670 | set_page_refcounted(last); | |
4671 | ||
4672 | last = page + (1UL << order); | |
4673 | for (page += nr; page < last; page++) | |
4674 | __free_pages_ok(page, 0, FPI_TO_TAIL); | |
4675 | } | |
4676 | return (void *)addr; | |
4677 | } | |
4678 | ||
4679 | /** | |
4680 | * alloc_pages_exact - allocate an exact number physically-contiguous pages. | |
4681 | * @size: the number of bytes to allocate | |
4682 | * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP | |
4683 | * | |
4684 | * This function is similar to alloc_pages(), except that it allocates the | |
4685 | * minimum number of pages to satisfy the request. alloc_pages() can only | |
4686 | * allocate memory in power-of-two pages. | |
4687 | * | |
4688 | * This function is also limited by MAX_ORDER. | |
4689 | * | |
4690 | * Memory allocated by this function must be released by free_pages_exact(). | |
4691 | * | |
4692 | * Return: pointer to the allocated area or %NULL in case of error. | |
4693 | */ | |
4694 | void *alloc_pages_exact(size_t size, gfp_t gfp_mask) | |
4695 | { | |
4696 | unsigned int order = get_order(size); | |
4697 | unsigned long addr; | |
4698 | ||
4699 | if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) | |
4700 | gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); | |
4701 | ||
4702 | addr = __get_free_pages(gfp_mask, order); | |
4703 | return make_alloc_exact(addr, order, size); | |
4704 | } | |
4705 | EXPORT_SYMBOL(alloc_pages_exact); | |
4706 | ||
4707 | /** | |
4708 | * alloc_pages_exact_nid - allocate an exact number of physically-contiguous | |
4709 | * pages on a node. | |
4710 | * @nid: the preferred node ID where memory should be allocated | |
4711 | * @size: the number of bytes to allocate | |
4712 | * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP | |
4713 | * | |
4714 | * Like alloc_pages_exact(), but try to allocate on node nid first before falling | |
4715 | * back. | |
4716 | * | |
4717 | * Return: pointer to the allocated area or %NULL in case of error. | |
4718 | */ | |
4719 | void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) | |
4720 | { | |
4721 | unsigned int order = get_order(size); | |
4722 | struct page *p; | |
4723 | ||
4724 | if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) | |
4725 | gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); | |
4726 | ||
4727 | p = alloc_pages_node(nid, gfp_mask, order); | |
4728 | if (!p) | |
4729 | return NULL; | |
4730 | return make_alloc_exact((unsigned long)page_address(p), order, size); | |
4731 | } | |
4732 | ||
4733 | /** | |
4734 | * free_pages_exact - release memory allocated via alloc_pages_exact() | |
4735 | * @virt: the value returned by alloc_pages_exact. | |
4736 | * @size: size of allocation, same value as passed to alloc_pages_exact(). | |
4737 | * | |
4738 | * Release the memory allocated by a previous call to alloc_pages_exact. | |
4739 | */ | |
4740 | void free_pages_exact(void *virt, size_t size) | |
4741 | { | |
4742 | unsigned long addr = (unsigned long)virt; | |
4743 | unsigned long end = addr + PAGE_ALIGN(size); | |
4744 | ||
4745 | while (addr < end) { | |
4746 | free_page(addr); | |
4747 | addr += PAGE_SIZE; | |
4748 | } | |
4749 | } | |
4750 | EXPORT_SYMBOL(free_pages_exact); | |
4751 | ||
4752 | /** | |
4753 | * nr_free_zone_pages - count number of pages beyond high watermark | |
4754 | * @offset: The zone index of the highest zone | |
4755 | * | |
4756 | * nr_free_zone_pages() counts the number of pages which are beyond the | |
4757 | * high watermark within all zones at or below a given zone index. For each | |
4758 | * zone, the number of pages is calculated as: | |
4759 | * | |
4760 | * nr_free_zone_pages = managed_pages - high_pages | |
4761 | * | |
4762 | * Return: number of pages beyond high watermark. | |
4763 | */ | |
4764 | static unsigned long nr_free_zone_pages(int offset) | |
4765 | { | |
4766 | struct zoneref *z; | |
4767 | struct zone *zone; | |
4768 | ||
4769 | /* Just pick one node, since fallback list is circular */ | |
4770 | unsigned long sum = 0; | |
4771 | ||
4772 | struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL); | |
4773 | ||
4774 | for_each_zone_zonelist(zone, z, zonelist, offset) { | |
4775 | unsigned long size = zone_managed_pages(zone); | |
4776 | unsigned long high = high_wmark_pages(zone); | |
4777 | if (size > high) | |
4778 | sum += size - high; | |
4779 | } | |
4780 | ||
4781 | return sum; | |
4782 | } | |
4783 | ||
4784 | /** | |
4785 | * nr_free_buffer_pages - count number of pages beyond high watermark | |
4786 | * | |
4787 | * nr_free_buffer_pages() counts the number of pages which are beyond the high | |
4788 | * watermark within ZONE_DMA and ZONE_NORMAL. | |
4789 | * | |
4790 | * Return: number of pages beyond high watermark within ZONE_DMA and | |
4791 | * ZONE_NORMAL. | |
4792 | */ | |
4793 | unsigned long nr_free_buffer_pages(void) | |
4794 | { | |
4795 | return nr_free_zone_pages(gfp_zone(GFP_USER)); | |
4796 | } | |
4797 | EXPORT_SYMBOL_GPL(nr_free_buffer_pages); | |
4798 | ||
4799 | static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) | |
4800 | { | |
4801 | zoneref->zone = zone; | |
4802 | zoneref->zone_idx = zone_idx(zone); | |
4803 | } | |
4804 | ||
4805 | /* | |
4806 | * Builds allocation fallback zone lists. | |
4807 | * | |
4808 | * Add all populated zones of a node to the zonelist. | |
4809 | */ | |
4810 | static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) | |
4811 | { | |
4812 | struct zone *zone; | |
4813 | enum zone_type zone_type = MAX_NR_ZONES; | |
4814 | int nr_zones = 0; | |
4815 | ||
4816 | do { | |
4817 | zone_type--; | |
4818 | zone = pgdat->node_zones + zone_type; | |
4819 | if (populated_zone(zone)) { | |
4820 | zoneref_set_zone(zone, &zonerefs[nr_zones++]); | |
4821 | check_highest_zone(zone_type); | |
4822 | } | |
4823 | } while (zone_type); | |
4824 | ||
4825 | return nr_zones; | |
4826 | } | |
4827 | ||
4828 | #ifdef CONFIG_NUMA | |
4829 | ||
4830 | static int __parse_numa_zonelist_order(char *s) | |
4831 | { | |
4832 | /* | |
4833 | * We used to support different zonelists modes but they turned | |
4834 | * out to be just not useful. Let's keep the warning in place | |
4835 | * if somebody still use the cmd line parameter so that we do | |
4836 | * not fail it silently | |
4837 | */ | |
4838 | if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) { | |
4839 | pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s); | |
4840 | return -EINVAL; | |
4841 | } | |
4842 | return 0; | |
4843 | } | |
4844 | ||
4845 | static char numa_zonelist_order[] = "Node"; | |
4846 | #define NUMA_ZONELIST_ORDER_LEN 16 | |
4847 | /* | |
4848 | * sysctl handler for numa_zonelist_order | |
4849 | */ | |
4850 | static int numa_zonelist_order_handler(struct ctl_table *table, int write, | |
4851 | void *buffer, size_t *length, loff_t *ppos) | |
4852 | { | |
4853 | if (write) | |
4854 | return __parse_numa_zonelist_order(buffer); | |
4855 | return proc_dostring(table, write, buffer, length, ppos); | |
4856 | } | |
4857 | ||
4858 | static int node_load[MAX_NUMNODES]; | |
4859 | ||
4860 | /** | |
4861 | * find_next_best_node - find the next node that should appear in a given node's fallback list | |
4862 | * @node: node whose fallback list we're appending | |
4863 | * @used_node_mask: nodemask_t of already used nodes | |
4864 | * | |
4865 | * We use a number of factors to determine which is the next node that should | |
4866 | * appear on a given node's fallback list. The node should not have appeared | |
4867 | * already in @node's fallback list, and it should be the next closest node | |
4868 | * according to the distance array (which contains arbitrary distance values | |
4869 | * from each node to each node in the system), and should also prefer nodes | |
4870 | * with no CPUs, since presumably they'll have very little allocation pressure | |
4871 | * on them otherwise. | |
4872 | * | |
4873 | * Return: node id of the found node or %NUMA_NO_NODE if no node is found. | |
4874 | */ | |
4875 | int find_next_best_node(int node, nodemask_t *used_node_mask) | |
4876 | { | |
4877 | int n, val; | |
4878 | int min_val = INT_MAX; | |
4879 | int best_node = NUMA_NO_NODE; | |
4880 | ||
4881 | /* Use the local node if we haven't already */ | |
4882 | if (!node_isset(node, *used_node_mask)) { | |
4883 | node_set(node, *used_node_mask); | |
4884 | return node; | |
4885 | } | |
4886 | ||
4887 | for_each_node_state(n, N_MEMORY) { | |
4888 | ||
4889 | /* Don't want a node to appear more than once */ | |
4890 | if (node_isset(n, *used_node_mask)) | |
4891 | continue; | |
4892 | ||
4893 | /* Use the distance array to find the distance */ | |
4894 | val = node_distance(node, n); | |
4895 | ||
4896 | /* Penalize nodes under us ("prefer the next node") */ | |
4897 | val += (n < node); | |
4898 | ||
4899 | /* Give preference to headless and unused nodes */ | |
4900 | if (!cpumask_empty(cpumask_of_node(n))) | |
4901 | val += PENALTY_FOR_NODE_WITH_CPUS; | |
4902 | ||
4903 | /* Slight preference for less loaded node */ | |
4904 | val *= MAX_NUMNODES; | |
4905 | val += node_load[n]; | |
4906 | ||
4907 | if (val < min_val) { | |
4908 | min_val = val; | |
4909 | best_node = n; | |
4910 | } | |
4911 | } | |
4912 | ||
4913 | if (best_node >= 0) | |
4914 | node_set(best_node, *used_node_mask); | |
4915 | ||
4916 | return best_node; | |
4917 | } | |
4918 | ||
4919 | ||
4920 | /* | |
4921 | * Build zonelists ordered by node and zones within node. | |
4922 | * This results in maximum locality--normal zone overflows into local | |
4923 | * DMA zone, if any--but risks exhausting DMA zone. | |
4924 | */ | |
4925 | static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, | |
4926 | unsigned nr_nodes) | |
4927 | { | |
4928 | struct zoneref *zonerefs; | |
4929 | int i; | |
4930 | ||
4931 | zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; | |
4932 | ||
4933 | for (i = 0; i < nr_nodes; i++) { | |
4934 | int nr_zones; | |
4935 | ||
4936 | pg_data_t *node = NODE_DATA(node_order[i]); | |
4937 | ||
4938 | nr_zones = build_zonerefs_node(node, zonerefs); | |
4939 | zonerefs += nr_zones; | |
4940 | } | |
4941 | zonerefs->zone = NULL; | |
4942 | zonerefs->zone_idx = 0; | |
4943 | } | |
4944 | ||
4945 | /* | |
4946 | * Build gfp_thisnode zonelists | |
4947 | */ | |
4948 | static void build_thisnode_zonelists(pg_data_t *pgdat) | |
4949 | { | |
4950 | struct zoneref *zonerefs; | |
4951 | int nr_zones; | |
4952 | ||
4953 | zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; | |
4954 | nr_zones = build_zonerefs_node(pgdat, zonerefs); | |
4955 | zonerefs += nr_zones; | |
4956 | zonerefs->zone = NULL; | |
4957 | zonerefs->zone_idx = 0; | |
4958 | } | |
4959 | ||
4960 | /* | |
4961 | * Build zonelists ordered by zone and nodes within zones. | |
4962 | * This results in conserving DMA zone[s] until all Normal memory is | |
4963 | * exhausted, but results in overflowing to remote node while memory | |
4964 | * may still exist in local DMA zone. | |
4965 | */ | |
4966 | ||
4967 | static void build_zonelists(pg_data_t *pgdat) | |
4968 | { | |
4969 | static int node_order[MAX_NUMNODES]; | |
4970 | int node, nr_nodes = 0; | |
4971 | nodemask_t used_mask = NODE_MASK_NONE; | |
4972 | int local_node, prev_node; | |
4973 | ||
4974 | /* NUMA-aware ordering of nodes */ | |
4975 | local_node = pgdat->node_id; | |
4976 | prev_node = local_node; | |
4977 | ||
4978 | memset(node_order, 0, sizeof(node_order)); | |
4979 | while ((node = find_next_best_node(local_node, &used_mask)) >= 0) { | |
4980 | /* | |
4981 | * We don't want to pressure a particular node. | |
4982 | * So adding penalty to the first node in same | |
4983 | * distance group to make it round-robin. | |
4984 | */ | |
4985 | if (node_distance(local_node, node) != | |
4986 | node_distance(local_node, prev_node)) | |
4987 | node_load[node] += 1; | |
4988 | ||
4989 | node_order[nr_nodes++] = node; | |
4990 | prev_node = node; | |
4991 | } | |
4992 | ||
4993 | build_zonelists_in_node_order(pgdat, node_order, nr_nodes); | |
4994 | build_thisnode_zonelists(pgdat); | |
4995 | pr_info("Fallback order for Node %d: ", local_node); | |
4996 | for (node = 0; node < nr_nodes; node++) | |
4997 | pr_cont("%d ", node_order[node]); | |
4998 | pr_cont("\n"); | |
4999 | } | |
5000 | ||
5001 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES | |
5002 | /* | |
5003 | * Return node id of node used for "local" allocations. | |
5004 | * I.e., first node id of first zone in arg node's generic zonelist. | |
5005 | * Used for initializing percpu 'numa_mem', which is used primarily | |
5006 | * for kernel allocations, so use GFP_KERNEL flags to locate zonelist. | |
5007 | */ | |
5008 | int local_memory_node(int node) | |
5009 | { | |
5010 | struct zoneref *z; | |
5011 | ||
5012 | z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL), | |
5013 | gfp_zone(GFP_KERNEL), | |
5014 | NULL); | |
5015 | return zone_to_nid(z->zone); | |
5016 | } | |
5017 | #endif | |
5018 | ||
5019 | static void setup_min_unmapped_ratio(void); | |
5020 | static void setup_min_slab_ratio(void); | |
5021 | #else /* CONFIG_NUMA */ | |
5022 | ||
5023 | static void build_zonelists(pg_data_t *pgdat) | |
5024 | { | |
5025 | int node, local_node; | |
5026 | struct zoneref *zonerefs; | |
5027 | int nr_zones; | |
5028 | ||
5029 | local_node = pgdat->node_id; | |
5030 | ||
5031 | zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; | |
5032 | nr_zones = build_zonerefs_node(pgdat, zonerefs); | |
5033 | zonerefs += nr_zones; | |
5034 | ||
5035 | /* | |
5036 | * Now we build the zonelist so that it contains the zones | |
5037 | * of all the other nodes. | |
5038 | * We don't want to pressure a particular node, so when | |
5039 | * building the zones for node N, we make sure that the | |
5040 | * zones coming right after the local ones are those from | |
5041 | * node N+1 (modulo N) | |
5042 | */ | |
5043 | for (node = local_node + 1; node < MAX_NUMNODES; node++) { | |
5044 | if (!node_online(node)) | |
5045 | continue; | |
5046 | nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); | |
5047 | zonerefs += nr_zones; | |
5048 | } | |
5049 | for (node = 0; node < local_node; node++) { | |
5050 | if (!node_online(node)) | |
5051 | continue; | |
5052 | nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); | |
5053 | zonerefs += nr_zones; | |
5054 | } | |
5055 | ||
5056 | zonerefs->zone = NULL; | |
5057 | zonerefs->zone_idx = 0; | |
5058 | } | |
5059 | ||
5060 | #endif /* CONFIG_NUMA */ | |
5061 | ||
5062 | /* | |
5063 | * Boot pageset table. One per cpu which is going to be used for all | |
5064 | * zones and all nodes. The parameters will be set in such a way | |
5065 | * that an item put on a list will immediately be handed over to | |
5066 | * the buddy list. This is safe since pageset manipulation is done | |
5067 | * with interrupts disabled. | |
5068 | * | |
5069 | * The boot_pagesets must be kept even after bootup is complete for | |
5070 | * unused processors and/or zones. They do play a role for bootstrapping | |
5071 | * hotplugged processors. | |
5072 | * | |
5073 | * zoneinfo_show() and maybe other functions do | |
5074 | * not check if the processor is online before following the pageset pointer. | |
5075 | * Other parts of the kernel may not check if the zone is available. | |
5076 | */ | |
5077 | static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats); | |
5078 | /* These effectively disable the pcplists in the boot pageset completely */ | |
5079 | #define BOOT_PAGESET_HIGH 0 | |
5080 | #define BOOT_PAGESET_BATCH 1 | |
5081 | static DEFINE_PER_CPU(struct per_cpu_pages, boot_pageset); | |
5082 | static DEFINE_PER_CPU(struct per_cpu_zonestat, boot_zonestats); | |
5083 | ||
5084 | static void __build_all_zonelists(void *data) | |
5085 | { | |
5086 | int nid; | |
5087 | int __maybe_unused cpu; | |
5088 | pg_data_t *self = data; | |
5089 | unsigned long flags; | |
5090 | ||
5091 | /* | |
5092 | * The zonelist_update_seq must be acquired with irqsave because the | |
5093 | * reader can be invoked from IRQ with GFP_ATOMIC. | |
5094 | */ | |
5095 | write_seqlock_irqsave(&zonelist_update_seq, flags); | |
5096 | /* | |
5097 | * Also disable synchronous printk() to prevent any printk() from | |
5098 | * trying to hold port->lock, for | |
5099 | * tty_insert_flip_string_and_push_buffer() on other CPU might be | |
5100 | * calling kmalloc(GFP_ATOMIC | __GFP_NOWARN) with port->lock held. | |
5101 | */ | |
5102 | printk_deferred_enter(); | |
5103 | ||
5104 | #ifdef CONFIG_NUMA | |
5105 | memset(node_load, 0, sizeof(node_load)); | |
5106 | #endif | |
5107 | ||
5108 | /* | |
5109 | * This node is hotadded and no memory is yet present. So just | |
5110 | * building zonelists is fine - no need to touch other nodes. | |
5111 | */ | |
5112 | if (self && !node_online(self->node_id)) { | |
5113 | build_zonelists(self); | |
5114 | } else { | |
5115 | /* | |
5116 | * All possible nodes have pgdat preallocated | |
5117 | * in free_area_init | |
5118 | */ | |
5119 | for_each_node(nid) { | |
5120 | pg_data_t *pgdat = NODE_DATA(nid); | |
5121 | ||
5122 | build_zonelists(pgdat); | |
5123 | } | |
5124 | ||
5125 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES | |
5126 | /* | |
5127 | * We now know the "local memory node" for each node-- | |
5128 | * i.e., the node of the first zone in the generic zonelist. | |
5129 | * Set up numa_mem percpu variable for on-line cpus. During | |
5130 | * boot, only the boot cpu should be on-line; we'll init the | |
5131 | * secondary cpus' numa_mem as they come on-line. During | |
5132 | * node/memory hotplug, we'll fixup all on-line cpus. | |
5133 | */ | |
5134 | for_each_online_cpu(cpu) | |
5135 | set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); | |
5136 | #endif | |
5137 | } | |
5138 | ||
5139 | printk_deferred_exit(); | |
5140 | write_sequnlock_irqrestore(&zonelist_update_seq, flags); | |
5141 | } | |
5142 | ||
5143 | static noinline void __init | |
5144 | build_all_zonelists_init(void) | |
5145 | { | |
5146 | int cpu; | |
5147 | ||
5148 | __build_all_zonelists(NULL); | |
5149 | ||
5150 | /* | |
5151 | * Initialize the boot_pagesets that are going to be used | |
5152 | * for bootstrapping processors. The real pagesets for | |
5153 | * each zone will be allocated later when the per cpu | |
5154 | * allocator is available. | |
5155 | * | |
5156 | * boot_pagesets are used also for bootstrapping offline | |
5157 | * cpus if the system is already booted because the pagesets | |
5158 | * are needed to initialize allocators on a specific cpu too. | |
5159 | * F.e. the percpu allocator needs the page allocator which | |
5160 | * needs the percpu allocator in order to allocate its pagesets | |
5161 | * (a chicken-egg dilemma). | |
5162 | */ | |
5163 | for_each_possible_cpu(cpu) | |
5164 | per_cpu_pages_init(&per_cpu(boot_pageset, cpu), &per_cpu(boot_zonestats, cpu)); | |
5165 | ||
5166 | mminit_verify_zonelist(); | |
5167 | cpuset_init_current_mems_allowed(); | |
5168 | } | |
5169 | ||
5170 | /* | |
5171 | * unless system_state == SYSTEM_BOOTING. | |
5172 | * | |
5173 | * __ref due to call of __init annotated helper build_all_zonelists_init | |
5174 | * [protected by SYSTEM_BOOTING]. | |
5175 | */ | |
5176 | void __ref build_all_zonelists(pg_data_t *pgdat) | |
5177 | { | |
5178 | unsigned long vm_total_pages; | |
5179 | ||
5180 | if (system_state == SYSTEM_BOOTING) { | |
5181 | build_all_zonelists_init(); | |
5182 | } else { | |
5183 | __build_all_zonelists(pgdat); | |
5184 | /* cpuset refresh routine should be here */ | |
5185 | } | |
5186 | /* Get the number of free pages beyond high watermark in all zones. */ | |
5187 | vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE)); | |
5188 | /* | |
5189 | * Disable grouping by mobility if the number of pages in the | |
5190 | * system is too low to allow the mechanism to work. It would be | |
5191 | * more accurate, but expensive to check per-zone. This check is | |
5192 | * made on memory-hotadd so a system can start with mobility | |
5193 | * disabled and enable it later | |
5194 | */ | |
5195 | if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES)) | |
5196 | page_group_by_mobility_disabled = 1; | |
5197 | else | |
5198 | page_group_by_mobility_disabled = 0; | |
5199 | ||
5200 | pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n", | |
5201 | nr_online_nodes, | |
5202 | page_group_by_mobility_disabled ? "off" : "on", | |
5203 | vm_total_pages); | |
5204 | #ifdef CONFIG_NUMA | |
5205 | pr_info("Policy zone: %s\n", zone_names[policy_zone]); | |
5206 | #endif | |
5207 | } | |
5208 | ||
5209 | static int zone_batchsize(struct zone *zone) | |
5210 | { | |
5211 | #ifdef CONFIG_MMU | |
5212 | int batch; | |
5213 | ||
5214 | /* | |
5215 | * The number of pages to batch allocate is either ~0.1% | |
5216 | * of the zone or 1MB, whichever is smaller. The batch | |
5217 | * size is striking a balance between allocation latency | |
5218 | * and zone lock contention. | |
5219 | */ | |
5220 | batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE); | |
5221 | batch /= 4; /* We effectively *= 4 below */ | |
5222 | if (batch < 1) | |
5223 | batch = 1; | |
5224 | ||
5225 | /* | |
5226 | * Clamp the batch to a 2^n - 1 value. Having a power | |
5227 | * of 2 value was found to be more likely to have | |
5228 | * suboptimal cache aliasing properties in some cases. | |
5229 | * | |
5230 | * For example if 2 tasks are alternately allocating | |
5231 | * batches of pages, one task can end up with a lot | |
5232 | * of pages of one half of the possible page colors | |
5233 | * and the other with pages of the other colors. | |
5234 | */ | |
5235 | batch = rounddown_pow_of_two(batch + batch/2) - 1; | |
5236 | ||
5237 | return batch; | |
5238 | ||
5239 | #else | |
5240 | /* The deferral and batching of frees should be suppressed under NOMMU | |
5241 | * conditions. | |
5242 | * | |
5243 | * The problem is that NOMMU needs to be able to allocate large chunks | |
5244 | * of contiguous memory as there's no hardware page translation to | |
5245 | * assemble apparent contiguous memory from discontiguous pages. | |
5246 | * | |
5247 | * Queueing large contiguous runs of pages for batching, however, | |
5248 | * causes the pages to actually be freed in smaller chunks. As there | |
5249 | * can be a significant delay between the individual batches being | |
5250 | * recycled, this leads to the once large chunks of space being | |
5251 | * fragmented and becoming unavailable for high-order allocations. | |
5252 | */ | |
5253 | return 0; | |
5254 | #endif | |
5255 | } | |
5256 | ||
5257 | static int percpu_pagelist_high_fraction; | |
5258 | static int zone_highsize(struct zone *zone, int batch, int cpu_online) | |
5259 | { | |
5260 | #ifdef CONFIG_MMU | |
5261 | int high; | |
5262 | int nr_split_cpus; | |
5263 | unsigned long total_pages; | |
5264 | ||
5265 | if (!percpu_pagelist_high_fraction) { | |
5266 | /* | |
5267 | * By default, the high value of the pcp is based on the zone | |
5268 | * low watermark so that if they are full then background | |
5269 | * reclaim will not be started prematurely. | |
5270 | */ | |
5271 | total_pages = low_wmark_pages(zone); | |
5272 | } else { | |
5273 | /* | |
5274 | * If percpu_pagelist_high_fraction is configured, the high | |
5275 | * value is based on a fraction of the managed pages in the | |
5276 | * zone. | |
5277 | */ | |
5278 | total_pages = zone_managed_pages(zone) / percpu_pagelist_high_fraction; | |
5279 | } | |
5280 | ||
5281 | /* | |
5282 | * Split the high value across all online CPUs local to the zone. Note | |
5283 | * that early in boot that CPUs may not be online yet and that during | |
5284 | * CPU hotplug that the cpumask is not yet updated when a CPU is being | |
5285 | * onlined. For memory nodes that have no CPUs, split pcp->high across | |
5286 | * all online CPUs to mitigate the risk that reclaim is triggered | |
5287 | * prematurely due to pages stored on pcp lists. | |
5288 | */ | |
5289 | nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online; | |
5290 | if (!nr_split_cpus) | |
5291 | nr_split_cpus = num_online_cpus(); | |
5292 | high = total_pages / nr_split_cpus; | |
5293 | ||
5294 | /* | |
5295 | * Ensure high is at least batch*4. The multiple is based on the | |
5296 | * historical relationship between high and batch. | |
5297 | */ | |
5298 | high = max(high, batch << 2); | |
5299 | ||
5300 | return high; | |
5301 | #else | |
5302 | return 0; | |
5303 | #endif | |
5304 | } | |
5305 | ||
5306 | /* | |
5307 | * pcp->high and pcp->batch values are related and generally batch is lower | |
5308 | * than high. They are also related to pcp->count such that count is lower | |
5309 | * than high, and as soon as it reaches high, the pcplist is flushed. | |
5310 | * | |
5311 | * However, guaranteeing these relations at all times would require e.g. write | |
5312 | * barriers here but also careful usage of read barriers at the read side, and | |
5313 | * thus be prone to error and bad for performance. Thus the update only prevents | |
5314 | * store tearing. Any new users of pcp->batch and pcp->high should ensure they | |
5315 | * can cope with those fields changing asynchronously, and fully trust only the | |
5316 | * pcp->count field on the local CPU with interrupts disabled. | |
5317 | * | |
5318 | * mutex_is_locked(&pcp_batch_high_lock) required when calling this function | |
5319 | * outside of boot time (or some other assurance that no concurrent updaters | |
5320 | * exist). | |
5321 | */ | |
5322 | static void pageset_update(struct per_cpu_pages *pcp, unsigned long high, | |
5323 | unsigned long batch) | |
5324 | { | |
5325 | WRITE_ONCE(pcp->batch, batch); | |
5326 | WRITE_ONCE(pcp->high, high); | |
5327 | } | |
5328 | ||
5329 | static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats) | |
5330 | { | |
5331 | int pindex; | |
5332 | ||
5333 | memset(pcp, 0, sizeof(*pcp)); | |
5334 | memset(pzstats, 0, sizeof(*pzstats)); | |
5335 | ||
5336 | spin_lock_init(&pcp->lock); | |
5337 | for (pindex = 0; pindex < NR_PCP_LISTS; pindex++) | |
5338 | INIT_LIST_HEAD(&pcp->lists[pindex]); | |
5339 | ||
5340 | /* | |
5341 | * Set batch and high values safe for a boot pageset. A true percpu | |
5342 | * pageset's initialization will update them subsequently. Here we don't | |
5343 | * need to be as careful as pageset_update() as nobody can access the | |
5344 | * pageset yet. | |
5345 | */ | |
5346 | pcp->high = BOOT_PAGESET_HIGH; | |
5347 | pcp->batch = BOOT_PAGESET_BATCH; | |
5348 | pcp->free_factor = 0; | |
5349 | } | |
5350 | ||
5351 | static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high, | |
5352 | unsigned long batch) | |
5353 | { | |
5354 | struct per_cpu_pages *pcp; | |
5355 | int cpu; | |
5356 | ||
5357 | for_each_possible_cpu(cpu) { | |
5358 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); | |
5359 | pageset_update(pcp, high, batch); | |
5360 | } | |
5361 | } | |
5362 | ||
5363 | /* | |
5364 | * Calculate and set new high and batch values for all per-cpu pagesets of a | |
5365 | * zone based on the zone's size. | |
5366 | */ | |
5367 | static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online) | |
5368 | { | |
5369 | int new_high, new_batch; | |
5370 | ||
5371 | new_batch = max(1, zone_batchsize(zone)); | |
5372 | new_high = zone_highsize(zone, new_batch, cpu_online); | |
5373 | ||
5374 | if (zone->pageset_high == new_high && | |
5375 | zone->pageset_batch == new_batch) | |
5376 | return; | |
5377 | ||
5378 | zone->pageset_high = new_high; | |
5379 | zone->pageset_batch = new_batch; | |
5380 | ||
5381 | __zone_set_pageset_high_and_batch(zone, new_high, new_batch); | |
5382 | } | |
5383 | ||
5384 | void __meminit setup_zone_pageset(struct zone *zone) | |
5385 | { | |
5386 | int cpu; | |
5387 | ||
5388 | /* Size may be 0 on !SMP && !NUMA */ | |
5389 | if (sizeof(struct per_cpu_zonestat) > 0) | |
5390 | zone->per_cpu_zonestats = alloc_percpu(struct per_cpu_zonestat); | |
5391 | ||
5392 | zone->per_cpu_pageset = alloc_percpu(struct per_cpu_pages); | |
5393 | for_each_possible_cpu(cpu) { | |
5394 | struct per_cpu_pages *pcp; | |
5395 | struct per_cpu_zonestat *pzstats; | |
5396 | ||
5397 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); | |
5398 | pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); | |
5399 | per_cpu_pages_init(pcp, pzstats); | |
5400 | } | |
5401 | ||
5402 | zone_set_pageset_high_and_batch(zone, 0); | |
5403 | } | |
5404 | ||
5405 | /* | |
5406 | * The zone indicated has a new number of managed_pages; batch sizes and percpu | |
5407 | * page high values need to be recalculated. | |
5408 | */ | |
5409 | static void zone_pcp_update(struct zone *zone, int cpu_online) | |
5410 | { | |
5411 | mutex_lock(&pcp_batch_high_lock); | |
5412 | zone_set_pageset_high_and_batch(zone, cpu_online); | |
5413 | mutex_unlock(&pcp_batch_high_lock); | |
5414 | } | |
5415 | ||
5416 | /* | |
5417 | * Allocate per cpu pagesets and initialize them. | |
5418 | * Before this call only boot pagesets were available. | |
5419 | */ | |
5420 | void __init setup_per_cpu_pageset(void) | |
5421 | { | |
5422 | struct pglist_data *pgdat; | |
5423 | struct zone *zone; | |
5424 | int __maybe_unused cpu; | |
5425 | ||
5426 | for_each_populated_zone(zone) | |
5427 | setup_zone_pageset(zone); | |
5428 | ||
5429 | #ifdef CONFIG_NUMA | |
5430 | /* | |
5431 | * Unpopulated zones continue using the boot pagesets. | |
5432 | * The numa stats for these pagesets need to be reset. | |
5433 | * Otherwise, they will end up skewing the stats of | |
5434 | * the nodes these zones are associated with. | |
5435 | */ | |
5436 | for_each_possible_cpu(cpu) { | |
5437 | struct per_cpu_zonestat *pzstats = &per_cpu(boot_zonestats, cpu); | |
5438 | memset(pzstats->vm_numa_event, 0, | |
5439 | sizeof(pzstats->vm_numa_event)); | |
5440 | } | |
5441 | #endif | |
5442 | ||
5443 | for_each_online_pgdat(pgdat) | |
5444 | pgdat->per_cpu_nodestats = | |
5445 | alloc_percpu(struct per_cpu_nodestat); | |
5446 | } | |
5447 | ||
5448 | __meminit void zone_pcp_init(struct zone *zone) | |
5449 | { | |
5450 | /* | |
5451 | * per cpu subsystem is not up at this point. The following code | |
5452 | * relies on the ability of the linker to provide the | |
5453 | * offset of a (static) per cpu variable into the per cpu area. | |
5454 | */ | |
5455 | zone->per_cpu_pageset = &boot_pageset; | |
5456 | zone->per_cpu_zonestats = &boot_zonestats; | |
5457 | zone->pageset_high = BOOT_PAGESET_HIGH; | |
5458 | zone->pageset_batch = BOOT_PAGESET_BATCH; | |
5459 | ||
5460 | if (populated_zone(zone)) | |
5461 | pr_debug(" %s zone: %lu pages, LIFO batch:%u\n", zone->name, | |
5462 | zone->present_pages, zone_batchsize(zone)); | |
5463 | } | |
5464 | ||
5465 | void adjust_managed_page_count(struct page *page, long count) | |
5466 | { | |
5467 | atomic_long_add(count, &page_zone(page)->managed_pages); | |
5468 | totalram_pages_add(count); | |
5469 | #ifdef CONFIG_HIGHMEM | |
5470 | if (PageHighMem(page)) | |
5471 | totalhigh_pages_add(count); | |
5472 | #endif | |
5473 | } | |
5474 | EXPORT_SYMBOL(adjust_managed_page_count); | |
5475 | ||
5476 | unsigned long free_reserved_area(void *start, void *end, int poison, const char *s) | |
5477 | { | |
5478 | void *pos; | |
5479 | unsigned long pages = 0; | |
5480 | ||
5481 | start = (void *)PAGE_ALIGN((unsigned long)start); | |
5482 | end = (void *)((unsigned long)end & PAGE_MASK); | |
5483 | for (pos = start; pos < end; pos += PAGE_SIZE, pages++) { | |
5484 | struct page *page = virt_to_page(pos); | |
5485 | void *direct_map_addr; | |
5486 | ||
5487 | /* | |
5488 | * 'direct_map_addr' might be different from 'pos' | |
5489 | * because some architectures' virt_to_page() | |
5490 | * work with aliases. Getting the direct map | |
5491 | * address ensures that we get a _writeable_ | |
5492 | * alias for the memset(). | |
5493 | */ | |
5494 | direct_map_addr = page_address(page); | |
5495 | /* | |
5496 | * Perform a kasan-unchecked memset() since this memory | |
5497 | * has not been initialized. | |
5498 | */ | |
5499 | direct_map_addr = kasan_reset_tag(direct_map_addr); | |
5500 | if ((unsigned int)poison <= 0xFF) | |
5501 | memset(direct_map_addr, poison, PAGE_SIZE); | |
5502 | ||
5503 | free_reserved_page(page); | |
5504 | } | |
5505 | ||
5506 | if (pages && s) | |
5507 | pr_info("Freeing %s memory: %ldK\n", s, K(pages)); | |
5508 | ||
5509 | return pages; | |
5510 | } | |
5511 | ||
5512 | static int page_alloc_cpu_dead(unsigned int cpu) | |
5513 | { | |
5514 | struct zone *zone; | |
5515 | ||
5516 | lru_add_drain_cpu(cpu); | |
5517 | mlock_drain_remote(cpu); | |
5518 | drain_pages(cpu); | |
5519 | ||
5520 | /* | |
5521 | * Spill the event counters of the dead processor | |
5522 | * into the current processors event counters. | |
5523 | * This artificially elevates the count of the current | |
5524 | * processor. | |
5525 | */ | |
5526 | vm_events_fold_cpu(cpu); | |
5527 | ||
5528 | /* | |
5529 | * Zero the differential counters of the dead processor | |
5530 | * so that the vm statistics are consistent. | |
5531 | * | |
5532 | * This is only okay since the processor is dead and cannot | |
5533 | * race with what we are doing. | |
5534 | */ | |
5535 | cpu_vm_stats_fold(cpu); | |
5536 | ||
5537 | for_each_populated_zone(zone) | |
5538 | zone_pcp_update(zone, 0); | |
5539 | ||
5540 | return 0; | |
5541 | } | |
5542 | ||
5543 | static int page_alloc_cpu_online(unsigned int cpu) | |
5544 | { | |
5545 | struct zone *zone; | |
5546 | ||
5547 | for_each_populated_zone(zone) | |
5548 | zone_pcp_update(zone, 1); | |
5549 | return 0; | |
5550 | } | |
5551 | ||
5552 | void __init page_alloc_init_cpuhp(void) | |
5553 | { | |
5554 | int ret; | |
5555 | ||
5556 | ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC, | |
5557 | "mm/page_alloc:pcp", | |
5558 | page_alloc_cpu_online, | |
5559 | page_alloc_cpu_dead); | |
5560 | WARN_ON(ret < 0); | |
5561 | } | |
5562 | ||
5563 | /* | |
5564 | * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio | |
5565 | * or min_free_kbytes changes. | |
5566 | */ | |
5567 | static void calculate_totalreserve_pages(void) | |
5568 | { | |
5569 | struct pglist_data *pgdat; | |
5570 | unsigned long reserve_pages = 0; | |
5571 | enum zone_type i, j; | |
5572 | ||
5573 | for_each_online_pgdat(pgdat) { | |
5574 | ||
5575 | pgdat->totalreserve_pages = 0; | |
5576 | ||
5577 | for (i = 0; i < MAX_NR_ZONES; i++) { | |
5578 | struct zone *zone = pgdat->node_zones + i; | |
5579 | long max = 0; | |
5580 | unsigned long managed_pages = zone_managed_pages(zone); | |
5581 | ||
5582 | /* Find valid and maximum lowmem_reserve in the zone */ | |
5583 | for (j = i; j < MAX_NR_ZONES; j++) { | |
5584 | if (zone->lowmem_reserve[j] > max) | |
5585 | max = zone->lowmem_reserve[j]; | |
5586 | } | |
5587 | ||
5588 | /* we treat the high watermark as reserved pages. */ | |
5589 | max += high_wmark_pages(zone); | |
5590 | ||
5591 | if (max > managed_pages) | |
5592 | max = managed_pages; | |
5593 | ||
5594 | pgdat->totalreserve_pages += max; | |
5595 | ||
5596 | reserve_pages += max; | |
5597 | } | |
5598 | } | |
5599 | totalreserve_pages = reserve_pages; | |
5600 | } | |
5601 | ||
5602 | /* | |
5603 | * setup_per_zone_lowmem_reserve - called whenever | |
5604 | * sysctl_lowmem_reserve_ratio changes. Ensures that each zone | |
5605 | * has a correct pages reserved value, so an adequate number of | |
5606 | * pages are left in the zone after a successful __alloc_pages(). | |
5607 | */ | |
5608 | static void setup_per_zone_lowmem_reserve(void) | |
5609 | { | |
5610 | struct pglist_data *pgdat; | |
5611 | enum zone_type i, j; | |
5612 | ||
5613 | for_each_online_pgdat(pgdat) { | |
5614 | for (i = 0; i < MAX_NR_ZONES - 1; i++) { | |
5615 | struct zone *zone = &pgdat->node_zones[i]; | |
5616 | int ratio = sysctl_lowmem_reserve_ratio[i]; | |
5617 | bool clear = !ratio || !zone_managed_pages(zone); | |
5618 | unsigned long managed_pages = 0; | |
5619 | ||
5620 | for (j = i + 1; j < MAX_NR_ZONES; j++) { | |
5621 | struct zone *upper_zone = &pgdat->node_zones[j]; | |
5622 | ||
5623 | managed_pages += zone_managed_pages(upper_zone); | |
5624 | ||
5625 | if (clear) | |
5626 | zone->lowmem_reserve[j] = 0; | |
5627 | else | |
5628 | zone->lowmem_reserve[j] = managed_pages / ratio; | |
5629 | } | |
5630 | } | |
5631 | } | |
5632 | ||
5633 | /* update totalreserve_pages */ | |
5634 | calculate_totalreserve_pages(); | |
5635 | } | |
5636 | ||
5637 | static void __setup_per_zone_wmarks(void) | |
5638 | { | |
5639 | unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10); | |
5640 | unsigned long lowmem_pages = 0; | |
5641 | struct zone *zone; | |
5642 | unsigned long flags; | |
5643 | ||
5644 | /* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */ | |
5645 | for_each_zone(zone) { | |
5646 | if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE) | |
5647 | lowmem_pages += zone_managed_pages(zone); | |
5648 | } | |
5649 | ||
5650 | for_each_zone(zone) { | |
5651 | u64 tmp; | |
5652 | ||
5653 | spin_lock_irqsave(&zone->lock, flags); | |
5654 | tmp = (u64)pages_min * zone_managed_pages(zone); | |
5655 | do_div(tmp, lowmem_pages); | |
5656 | if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) { | |
5657 | /* | |
5658 | * __GFP_HIGH and PF_MEMALLOC allocations usually don't | |
5659 | * need highmem and movable zones pages, so cap pages_min | |
5660 | * to a small value here. | |
5661 | * | |
5662 | * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN) | |
5663 | * deltas control async page reclaim, and so should | |
5664 | * not be capped for highmem and movable zones. | |
5665 | */ | |
5666 | unsigned long min_pages; | |
5667 | ||
5668 | min_pages = zone_managed_pages(zone) / 1024; | |
5669 | min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL); | |
5670 | zone->_watermark[WMARK_MIN] = min_pages; | |
5671 | } else { | |
5672 | /* | |
5673 | * If it's a lowmem zone, reserve a number of pages | |
5674 | * proportionate to the zone's size. | |
5675 | */ | |
5676 | zone->_watermark[WMARK_MIN] = tmp; | |
5677 | } | |
5678 | ||
5679 | /* | |
5680 | * Set the kswapd watermarks distance according to the | |
5681 | * scale factor in proportion to available memory, but | |
5682 | * ensure a minimum size on small systems. | |
5683 | */ | |
5684 | tmp = max_t(u64, tmp >> 2, | |
5685 | mult_frac(zone_managed_pages(zone), | |
5686 | watermark_scale_factor, 10000)); | |
5687 | ||
5688 | zone->watermark_boost = 0; | |
5689 | zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; | |
5690 | zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp; | |
5691 | zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp; | |
5692 | ||
5693 | spin_unlock_irqrestore(&zone->lock, flags); | |
5694 | } | |
5695 | ||
5696 | /* update totalreserve_pages */ | |
5697 | calculate_totalreserve_pages(); | |
5698 | } | |
5699 | ||
5700 | /** | |
5701 | * setup_per_zone_wmarks - called when min_free_kbytes changes | |
5702 | * or when memory is hot-{added|removed} | |
5703 | * | |
5704 | * Ensures that the watermark[min,low,high] values for each zone are set | |
5705 | * correctly with respect to min_free_kbytes. | |
5706 | */ | |
5707 | void setup_per_zone_wmarks(void) | |
5708 | { | |
5709 | struct zone *zone; | |
5710 | static DEFINE_SPINLOCK(lock); | |
5711 | ||
5712 | spin_lock(&lock); | |
5713 | __setup_per_zone_wmarks(); | |
5714 | spin_unlock(&lock); | |
5715 | ||
5716 | /* | |
5717 | * The watermark size have changed so update the pcpu batch | |
5718 | * and high limits or the limits may be inappropriate. | |
5719 | */ | |
5720 | for_each_zone(zone) | |
5721 | zone_pcp_update(zone, 0); | |
5722 | } | |
5723 | ||
5724 | /* | |
5725 | * Initialise min_free_kbytes. | |
5726 | * | |
5727 | * For small machines we want it small (128k min). For large machines | |
5728 | * we want it large (256MB max). But it is not linear, because network | |
5729 | * bandwidth does not increase linearly with machine size. We use | |
5730 | * | |
5731 | * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy: | |
5732 | * min_free_kbytes = sqrt(lowmem_kbytes * 16) | |
5733 | * | |
5734 | * which yields | |
5735 | * | |
5736 | * 16MB: 512k | |
5737 | * 32MB: 724k | |
5738 | * 64MB: 1024k | |
5739 | * 128MB: 1448k | |
5740 | * 256MB: 2048k | |
5741 | * 512MB: 2896k | |
5742 | * 1024MB: 4096k | |
5743 | * 2048MB: 5792k | |
5744 | * 4096MB: 8192k | |
5745 | * 8192MB: 11584k | |
5746 | * 16384MB: 16384k | |
5747 | */ | |
5748 | void calculate_min_free_kbytes(void) | |
5749 | { | |
5750 | unsigned long lowmem_kbytes; | |
5751 | int new_min_free_kbytes; | |
5752 | ||
5753 | lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10); | |
5754 | new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16); | |
5755 | ||
5756 | if (new_min_free_kbytes > user_min_free_kbytes) | |
5757 | min_free_kbytes = clamp(new_min_free_kbytes, 128, 262144); | |
5758 | else | |
5759 | pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n", | |
5760 | new_min_free_kbytes, user_min_free_kbytes); | |
5761 | ||
5762 | } | |
5763 | ||
5764 | int __meminit init_per_zone_wmark_min(void) | |
5765 | { | |
5766 | calculate_min_free_kbytes(); | |
5767 | setup_per_zone_wmarks(); | |
5768 | refresh_zone_stat_thresholds(); | |
5769 | setup_per_zone_lowmem_reserve(); | |
5770 | ||
5771 | #ifdef CONFIG_NUMA | |
5772 | setup_min_unmapped_ratio(); | |
5773 | setup_min_slab_ratio(); | |
5774 | #endif | |
5775 | ||
5776 | khugepaged_min_free_kbytes_update(); | |
5777 | ||
5778 | return 0; | |
5779 | } | |
5780 | postcore_initcall(init_per_zone_wmark_min) | |
5781 | ||
5782 | /* | |
5783 | * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so | |
5784 | * that we can call two helper functions whenever min_free_kbytes | |
5785 | * changes. | |
5786 | */ | |
5787 | static int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write, | |
5788 | void *buffer, size_t *length, loff_t *ppos) | |
5789 | { | |
5790 | int rc; | |
5791 | ||
5792 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5793 | if (rc) | |
5794 | return rc; | |
5795 | ||
5796 | if (write) { | |
5797 | user_min_free_kbytes = min_free_kbytes; | |
5798 | setup_per_zone_wmarks(); | |
5799 | } | |
5800 | return 0; | |
5801 | } | |
5802 | ||
5803 | static int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write, | |
5804 | void *buffer, size_t *length, loff_t *ppos) | |
5805 | { | |
5806 | int rc; | |
5807 | ||
5808 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5809 | if (rc) | |
5810 | return rc; | |
5811 | ||
5812 | if (write) | |
5813 | setup_per_zone_wmarks(); | |
5814 | ||
5815 | return 0; | |
5816 | } | |
5817 | ||
5818 | #ifdef CONFIG_NUMA | |
5819 | static void setup_min_unmapped_ratio(void) | |
5820 | { | |
5821 | pg_data_t *pgdat; | |
5822 | struct zone *zone; | |
5823 | ||
5824 | for_each_online_pgdat(pgdat) | |
5825 | pgdat->min_unmapped_pages = 0; | |
5826 | ||
5827 | for_each_zone(zone) | |
5828 | zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) * | |
5829 | sysctl_min_unmapped_ratio) / 100; | |
5830 | } | |
5831 | ||
5832 | ||
5833 | static int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write, | |
5834 | void *buffer, size_t *length, loff_t *ppos) | |
5835 | { | |
5836 | int rc; | |
5837 | ||
5838 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5839 | if (rc) | |
5840 | return rc; | |
5841 | ||
5842 | setup_min_unmapped_ratio(); | |
5843 | ||
5844 | return 0; | |
5845 | } | |
5846 | ||
5847 | static void setup_min_slab_ratio(void) | |
5848 | { | |
5849 | pg_data_t *pgdat; | |
5850 | struct zone *zone; | |
5851 | ||
5852 | for_each_online_pgdat(pgdat) | |
5853 | pgdat->min_slab_pages = 0; | |
5854 | ||
5855 | for_each_zone(zone) | |
5856 | zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) * | |
5857 | sysctl_min_slab_ratio) / 100; | |
5858 | } | |
5859 | ||
5860 | static int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write, | |
5861 | void *buffer, size_t *length, loff_t *ppos) | |
5862 | { | |
5863 | int rc; | |
5864 | ||
5865 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5866 | if (rc) | |
5867 | return rc; | |
5868 | ||
5869 | setup_min_slab_ratio(); | |
5870 | ||
5871 | return 0; | |
5872 | } | |
5873 | #endif | |
5874 | ||
5875 | /* | |
5876 | * lowmem_reserve_ratio_sysctl_handler - just a wrapper around | |
5877 | * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve() | |
5878 | * whenever sysctl_lowmem_reserve_ratio changes. | |
5879 | * | |
5880 | * The reserve ratio obviously has absolutely no relation with the | |
5881 | * minimum watermarks. The lowmem reserve ratio can only make sense | |
5882 | * if in function of the boot time zone sizes. | |
5883 | */ | |
5884 | static int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, | |
5885 | int write, void *buffer, size_t *length, loff_t *ppos) | |
5886 | { | |
5887 | int i; | |
5888 | ||
5889 | proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5890 | ||
5891 | for (i = 0; i < MAX_NR_ZONES; i++) { | |
5892 | if (sysctl_lowmem_reserve_ratio[i] < 1) | |
5893 | sysctl_lowmem_reserve_ratio[i] = 0; | |
5894 | } | |
5895 | ||
5896 | setup_per_zone_lowmem_reserve(); | |
5897 | return 0; | |
5898 | } | |
5899 | ||
5900 | /* | |
5901 | * percpu_pagelist_high_fraction - changes the pcp->high for each zone on each | |
5902 | * cpu. It is the fraction of total pages in each zone that a hot per cpu | |
5903 | * pagelist can have before it gets flushed back to buddy allocator. | |
5904 | */ | |
5905 | static int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *table, | |
5906 | int write, void *buffer, size_t *length, loff_t *ppos) | |
5907 | { | |
5908 | struct zone *zone; | |
5909 | int old_percpu_pagelist_high_fraction; | |
5910 | int ret; | |
5911 | ||
5912 | mutex_lock(&pcp_batch_high_lock); | |
5913 | old_percpu_pagelist_high_fraction = percpu_pagelist_high_fraction; | |
5914 | ||
5915 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
5916 | if (!write || ret < 0) | |
5917 | goto out; | |
5918 | ||
5919 | /* Sanity checking to avoid pcp imbalance */ | |
5920 | if (percpu_pagelist_high_fraction && | |
5921 | percpu_pagelist_high_fraction < MIN_PERCPU_PAGELIST_HIGH_FRACTION) { | |
5922 | percpu_pagelist_high_fraction = old_percpu_pagelist_high_fraction; | |
5923 | ret = -EINVAL; | |
5924 | goto out; | |
5925 | } | |
5926 | ||
5927 | /* No change? */ | |
5928 | if (percpu_pagelist_high_fraction == old_percpu_pagelist_high_fraction) | |
5929 | goto out; | |
5930 | ||
5931 | for_each_populated_zone(zone) | |
5932 | zone_set_pageset_high_and_batch(zone, 0); | |
5933 | out: | |
5934 | mutex_unlock(&pcp_batch_high_lock); | |
5935 | return ret; | |
5936 | } | |
5937 | ||
5938 | static struct ctl_table page_alloc_sysctl_table[] = { | |
5939 | { | |
5940 | .procname = "min_free_kbytes", | |
5941 | .data = &min_free_kbytes, | |
5942 | .maxlen = sizeof(min_free_kbytes), | |
5943 | .mode = 0644, | |
5944 | .proc_handler = min_free_kbytes_sysctl_handler, | |
5945 | .extra1 = SYSCTL_ZERO, | |
5946 | }, | |
5947 | { | |
5948 | .procname = "watermark_boost_factor", | |
5949 | .data = &watermark_boost_factor, | |
5950 | .maxlen = sizeof(watermark_boost_factor), | |
5951 | .mode = 0644, | |
5952 | .proc_handler = proc_dointvec_minmax, | |
5953 | .extra1 = SYSCTL_ZERO, | |
5954 | }, | |
5955 | { | |
5956 | .procname = "watermark_scale_factor", | |
5957 | .data = &watermark_scale_factor, | |
5958 | .maxlen = sizeof(watermark_scale_factor), | |
5959 | .mode = 0644, | |
5960 | .proc_handler = watermark_scale_factor_sysctl_handler, | |
5961 | .extra1 = SYSCTL_ONE, | |
5962 | .extra2 = SYSCTL_THREE_THOUSAND, | |
5963 | }, | |
5964 | { | |
5965 | .procname = "percpu_pagelist_high_fraction", | |
5966 | .data = &percpu_pagelist_high_fraction, | |
5967 | .maxlen = sizeof(percpu_pagelist_high_fraction), | |
5968 | .mode = 0644, | |
5969 | .proc_handler = percpu_pagelist_high_fraction_sysctl_handler, | |
5970 | .extra1 = SYSCTL_ZERO, | |
5971 | }, | |
5972 | { | |
5973 | .procname = "lowmem_reserve_ratio", | |
5974 | .data = &sysctl_lowmem_reserve_ratio, | |
5975 | .maxlen = sizeof(sysctl_lowmem_reserve_ratio), | |
5976 | .mode = 0644, | |
5977 | .proc_handler = lowmem_reserve_ratio_sysctl_handler, | |
5978 | }, | |
5979 | #ifdef CONFIG_NUMA | |
5980 | { | |
5981 | .procname = "numa_zonelist_order", | |
5982 | .data = &numa_zonelist_order, | |
5983 | .maxlen = NUMA_ZONELIST_ORDER_LEN, | |
5984 | .mode = 0644, | |
5985 | .proc_handler = numa_zonelist_order_handler, | |
5986 | }, | |
5987 | { | |
5988 | .procname = "min_unmapped_ratio", | |
5989 | .data = &sysctl_min_unmapped_ratio, | |
5990 | .maxlen = sizeof(sysctl_min_unmapped_ratio), | |
5991 | .mode = 0644, | |
5992 | .proc_handler = sysctl_min_unmapped_ratio_sysctl_handler, | |
5993 | .extra1 = SYSCTL_ZERO, | |
5994 | .extra2 = SYSCTL_ONE_HUNDRED, | |
5995 | }, | |
5996 | { | |
5997 | .procname = "min_slab_ratio", | |
5998 | .data = &sysctl_min_slab_ratio, | |
5999 | .maxlen = sizeof(sysctl_min_slab_ratio), | |
6000 | .mode = 0644, | |
6001 | .proc_handler = sysctl_min_slab_ratio_sysctl_handler, | |
6002 | .extra1 = SYSCTL_ZERO, | |
6003 | .extra2 = SYSCTL_ONE_HUNDRED, | |
6004 | }, | |
6005 | #endif | |
6006 | {} | |
6007 | }; | |
6008 | ||
6009 | void __init page_alloc_sysctl_init(void) | |
6010 | { | |
6011 | register_sysctl_init("vm", page_alloc_sysctl_table); | |
6012 | } | |
6013 | ||
6014 | #ifdef CONFIG_CONTIG_ALLOC | |
6015 | /* Usage: See admin-guide/dynamic-debug-howto.rst */ | |
6016 | static void alloc_contig_dump_pages(struct list_head *page_list) | |
6017 | { | |
6018 | DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure"); | |
6019 | ||
6020 | if (DYNAMIC_DEBUG_BRANCH(descriptor)) { | |
6021 | struct page *page; | |
6022 | ||
6023 | dump_stack(); | |
6024 | list_for_each_entry(page, page_list, lru) | |
6025 | dump_page(page, "migration failure"); | |
6026 | } | |
6027 | } | |
6028 | ||
6029 | /* [start, end) must belong to a single zone. */ | |
6030 | int __alloc_contig_migrate_range(struct compact_control *cc, | |
6031 | unsigned long start, unsigned long end) | |
6032 | { | |
6033 | /* This function is based on compact_zone() from compaction.c. */ | |
6034 | unsigned int nr_reclaimed; | |
6035 | unsigned long pfn = start; | |
6036 | unsigned int tries = 0; | |
6037 | int ret = 0; | |
6038 | struct migration_target_control mtc = { | |
6039 | .nid = zone_to_nid(cc->zone), | |
6040 | .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, | |
6041 | }; | |
6042 | ||
6043 | lru_cache_disable(); | |
6044 | ||
6045 | while (pfn < end || !list_empty(&cc->migratepages)) { | |
6046 | if (fatal_signal_pending(current)) { | |
6047 | ret = -EINTR; | |
6048 | break; | |
6049 | } | |
6050 | ||
6051 | if (list_empty(&cc->migratepages)) { | |
6052 | cc->nr_migratepages = 0; | |
6053 | ret = isolate_migratepages_range(cc, pfn, end); | |
6054 | if (ret && ret != -EAGAIN) | |
6055 | break; | |
6056 | pfn = cc->migrate_pfn; | |
6057 | tries = 0; | |
6058 | } else if (++tries == 5) { | |
6059 | ret = -EBUSY; | |
6060 | break; | |
6061 | } | |
6062 | ||
6063 | nr_reclaimed = reclaim_clean_pages_from_list(cc->zone, | |
6064 | &cc->migratepages); | |
6065 | cc->nr_migratepages -= nr_reclaimed; | |
6066 | ||
6067 | ret = migrate_pages(&cc->migratepages, alloc_migration_target, | |
6068 | NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE, NULL); | |
6069 | ||
6070 | /* | |
6071 | * On -ENOMEM, migrate_pages() bails out right away. It is pointless | |
6072 | * to retry again over this error, so do the same here. | |
6073 | */ | |
6074 | if (ret == -ENOMEM) | |
6075 | break; | |
6076 | } | |
6077 | ||
6078 | lru_cache_enable(); | |
6079 | if (ret < 0) { | |
6080 | if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY) | |
6081 | alloc_contig_dump_pages(&cc->migratepages); | |
6082 | putback_movable_pages(&cc->migratepages); | |
6083 | return ret; | |
6084 | } | |
6085 | return 0; | |
6086 | } | |
6087 | ||
6088 | /** | |
6089 | * alloc_contig_range() -- tries to allocate given range of pages | |
6090 | * @start: start PFN to allocate | |
6091 | * @end: one-past-the-last PFN to allocate | |
6092 | * @migratetype: migratetype of the underlying pageblocks (either | |
6093 | * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks | |
6094 | * in range must have the same migratetype and it must | |
6095 | * be either of the two. | |
6096 | * @gfp_mask: GFP mask to use during compaction | |
6097 | * | |
6098 | * The PFN range does not have to be pageblock aligned. The PFN range must | |
6099 | * belong to a single zone. | |
6100 | * | |
6101 | * The first thing this routine does is attempt to MIGRATE_ISOLATE all | |
6102 | * pageblocks in the range. Once isolated, the pageblocks should not | |
6103 | * be modified by others. | |
6104 | * | |
6105 | * Return: zero on success or negative error code. On success all | |
6106 | * pages which PFN is in [start, end) are allocated for the caller and | |
6107 | * need to be freed with free_contig_range(). | |
6108 | */ | |
6109 | int alloc_contig_range(unsigned long start, unsigned long end, | |
6110 | unsigned migratetype, gfp_t gfp_mask) | |
6111 | { | |
6112 | unsigned long outer_start, outer_end; | |
6113 | int order; | |
6114 | int ret = 0; | |
6115 | ||
6116 | struct compact_control cc = { | |
6117 | .nr_migratepages = 0, | |
6118 | .order = -1, | |
6119 | .zone = page_zone(pfn_to_page(start)), | |
6120 | .mode = MIGRATE_SYNC, | |
6121 | .ignore_skip_hint = true, | |
6122 | .no_set_skip_hint = true, | |
6123 | .gfp_mask = current_gfp_context(gfp_mask), | |
6124 | .alloc_contig = true, | |
6125 | }; | |
6126 | INIT_LIST_HEAD(&cc.migratepages); | |
6127 | ||
6128 | /* | |
6129 | * What we do here is we mark all pageblocks in range as | |
6130 | * MIGRATE_ISOLATE. Because pageblock and max order pages may | |
6131 | * have different sizes, and due to the way page allocator | |
6132 | * work, start_isolate_page_range() has special handlings for this. | |
6133 | * | |
6134 | * Once the pageblocks are marked as MIGRATE_ISOLATE, we | |
6135 | * migrate the pages from an unaligned range (ie. pages that | |
6136 | * we are interested in). This will put all the pages in | |
6137 | * range back to page allocator as MIGRATE_ISOLATE. | |
6138 | * | |
6139 | * When this is done, we take the pages in range from page | |
6140 | * allocator removing them from the buddy system. This way | |
6141 | * page allocator will never consider using them. | |
6142 | * | |
6143 | * This lets us mark the pageblocks back as | |
6144 | * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the | |
6145 | * aligned range but not in the unaligned, original range are | |
6146 | * put back to page allocator so that buddy can use them. | |
6147 | */ | |
6148 | ||
6149 | ret = start_isolate_page_range(start, end, migratetype, 0, gfp_mask); | |
6150 | if (ret) | |
6151 | goto done; | |
6152 | ||
6153 | drain_all_pages(cc.zone); | |
6154 | ||
6155 | /* | |
6156 | * In case of -EBUSY, we'd like to know which page causes problem. | |
6157 | * So, just fall through. test_pages_isolated() has a tracepoint | |
6158 | * which will report the busy page. | |
6159 | * | |
6160 | * It is possible that busy pages could become available before | |
6161 | * the call to test_pages_isolated, and the range will actually be | |
6162 | * allocated. So, if we fall through be sure to clear ret so that | |
6163 | * -EBUSY is not accidentally used or returned to caller. | |
6164 | */ | |
6165 | ret = __alloc_contig_migrate_range(&cc, start, end); | |
6166 | if (ret && ret != -EBUSY) | |
6167 | goto done; | |
6168 | ret = 0; | |
6169 | ||
6170 | /* | |
6171 | * Pages from [start, end) are within a pageblock_nr_pages | |
6172 | * aligned blocks that are marked as MIGRATE_ISOLATE. What's | |
6173 | * more, all pages in [start, end) are free in page allocator. | |
6174 | * What we are going to do is to allocate all pages from | |
6175 | * [start, end) (that is remove them from page allocator). | |
6176 | * | |
6177 | * The only problem is that pages at the beginning and at the | |
6178 | * end of interesting range may be not aligned with pages that | |
6179 | * page allocator holds, ie. they can be part of higher order | |
6180 | * pages. Because of this, we reserve the bigger range and | |
6181 | * once this is done free the pages we are not interested in. | |
6182 | * | |
6183 | * We don't have to hold zone->lock here because the pages are | |
6184 | * isolated thus they won't get removed from buddy. | |
6185 | */ | |
6186 | ||
6187 | order = 0; | |
6188 | outer_start = start; | |
6189 | while (!PageBuddy(pfn_to_page(outer_start))) { | |
6190 | if (++order > MAX_ORDER) { | |
6191 | outer_start = start; | |
6192 | break; | |
6193 | } | |
6194 | outer_start &= ~0UL << order; | |
6195 | } | |
6196 | ||
6197 | if (outer_start != start) { | |
6198 | order = buddy_order(pfn_to_page(outer_start)); | |
6199 | ||
6200 | /* | |
6201 | * outer_start page could be small order buddy page and | |
6202 | * it doesn't include start page. Adjust outer_start | |
6203 | * in this case to report failed page properly | |
6204 | * on tracepoint in test_pages_isolated() | |
6205 | */ | |
6206 | if (outer_start + (1UL << order) <= start) | |
6207 | outer_start = start; | |
6208 | } | |
6209 | ||
6210 | /* Make sure the range is really isolated. */ | |
6211 | if (test_pages_isolated(outer_start, end, 0)) { | |
6212 | ret = -EBUSY; | |
6213 | goto done; | |
6214 | } | |
6215 | ||
6216 | /* Grab isolated pages from freelists. */ | |
6217 | outer_end = isolate_freepages_range(&cc, outer_start, end); | |
6218 | if (!outer_end) { | |
6219 | ret = -EBUSY; | |
6220 | goto done; | |
6221 | } | |
6222 | ||
6223 | /* Free head and tail (if any) */ | |
6224 | if (start != outer_start) | |
6225 | free_contig_range(outer_start, start - outer_start); | |
6226 | if (end != outer_end) | |
6227 | free_contig_range(end, outer_end - end); | |
6228 | ||
6229 | done: | |
6230 | undo_isolate_page_range(start, end, migratetype); | |
6231 | return ret; | |
6232 | } | |
6233 | EXPORT_SYMBOL(alloc_contig_range); | |
6234 | ||
6235 | static int __alloc_contig_pages(unsigned long start_pfn, | |
6236 | unsigned long nr_pages, gfp_t gfp_mask) | |
6237 | { | |
6238 | unsigned long end_pfn = start_pfn + nr_pages; | |
6239 | ||
6240 | return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, | |
6241 | gfp_mask); | |
6242 | } | |
6243 | ||
6244 | static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn, | |
6245 | unsigned long nr_pages) | |
6246 | { | |
6247 | unsigned long i, end_pfn = start_pfn + nr_pages; | |
6248 | struct page *page; | |
6249 | ||
6250 | for (i = start_pfn; i < end_pfn; i++) { | |
6251 | page = pfn_to_online_page(i); | |
6252 | if (!page) | |
6253 | return false; | |
6254 | ||
6255 | if (page_zone(page) != z) | |
6256 | return false; | |
6257 | ||
6258 | if (PageReserved(page)) | |
6259 | return false; | |
6260 | ||
6261 | if (PageHuge(page)) | |
6262 | return false; | |
6263 | } | |
6264 | return true; | |
6265 | } | |
6266 | ||
6267 | static bool zone_spans_last_pfn(const struct zone *zone, | |
6268 | unsigned long start_pfn, unsigned long nr_pages) | |
6269 | { | |
6270 | unsigned long last_pfn = start_pfn + nr_pages - 1; | |
6271 | ||
6272 | return zone_spans_pfn(zone, last_pfn); | |
6273 | } | |
6274 | ||
6275 | /** | |
6276 | * alloc_contig_pages() -- tries to find and allocate contiguous range of pages | |
6277 | * @nr_pages: Number of contiguous pages to allocate | |
6278 | * @gfp_mask: GFP mask to limit search and used during compaction | |
6279 | * @nid: Target node | |
6280 | * @nodemask: Mask for other possible nodes | |
6281 | * | |
6282 | * This routine is a wrapper around alloc_contig_range(). It scans over zones | |
6283 | * on an applicable zonelist to find a contiguous pfn range which can then be | |
6284 | * tried for allocation with alloc_contig_range(). This routine is intended | |
6285 | * for allocation requests which can not be fulfilled with the buddy allocator. | |
6286 | * | |
6287 | * The allocated memory is always aligned to a page boundary. If nr_pages is a | |
6288 | * power of two, then allocated range is also guaranteed to be aligned to same | |
6289 | * nr_pages (e.g. 1GB request would be aligned to 1GB). | |
6290 | * | |
6291 | * Allocated pages can be freed with free_contig_range() or by manually calling | |
6292 | * __free_page() on each allocated page. | |
6293 | * | |
6294 | * Return: pointer to contiguous pages on success, or NULL if not successful. | |
6295 | */ | |
6296 | struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask, | |
6297 | int nid, nodemask_t *nodemask) | |
6298 | { | |
6299 | unsigned long ret, pfn, flags; | |
6300 | struct zonelist *zonelist; | |
6301 | struct zone *zone; | |
6302 | struct zoneref *z; | |
6303 | ||
6304 | zonelist = node_zonelist(nid, gfp_mask); | |
6305 | for_each_zone_zonelist_nodemask(zone, z, zonelist, | |
6306 | gfp_zone(gfp_mask), nodemask) { | |
6307 | spin_lock_irqsave(&zone->lock, flags); | |
6308 | ||
6309 | pfn = ALIGN(zone->zone_start_pfn, nr_pages); | |
6310 | while (zone_spans_last_pfn(zone, pfn, nr_pages)) { | |
6311 | if (pfn_range_valid_contig(zone, pfn, nr_pages)) { | |
6312 | /* | |
6313 | * We release the zone lock here because | |
6314 | * alloc_contig_range() will also lock the zone | |
6315 | * at some point. If there's an allocation | |
6316 | * spinning on this lock, it may win the race | |
6317 | * and cause alloc_contig_range() to fail... | |
6318 | */ | |
6319 | spin_unlock_irqrestore(&zone->lock, flags); | |
6320 | ret = __alloc_contig_pages(pfn, nr_pages, | |
6321 | gfp_mask); | |
6322 | if (!ret) | |
6323 | return pfn_to_page(pfn); | |
6324 | spin_lock_irqsave(&zone->lock, flags); | |
6325 | } | |
6326 | pfn += nr_pages; | |
6327 | } | |
6328 | spin_unlock_irqrestore(&zone->lock, flags); | |
6329 | } | |
6330 | return NULL; | |
6331 | } | |
6332 | #endif /* CONFIG_CONTIG_ALLOC */ | |
6333 | ||
6334 | void free_contig_range(unsigned long pfn, unsigned long nr_pages) | |
6335 | { | |
6336 | unsigned long count = 0; | |
6337 | ||
6338 | for (; nr_pages--; pfn++) { | |
6339 | struct page *page = pfn_to_page(pfn); | |
6340 | ||
6341 | count += page_count(page) != 1; | |
6342 | __free_page(page); | |
6343 | } | |
6344 | WARN(count != 0, "%lu pages are still in use!\n", count); | |
6345 | } | |
6346 | EXPORT_SYMBOL(free_contig_range); | |
6347 | ||
6348 | /* | |
6349 | * Effectively disable pcplists for the zone by setting the high limit to 0 | |
6350 | * and draining all cpus. A concurrent page freeing on another CPU that's about | |
6351 | * to put the page on pcplist will either finish before the drain and the page | |
6352 | * will be drained, or observe the new high limit and skip the pcplist. | |
6353 | * | |
6354 | * Must be paired with a call to zone_pcp_enable(). | |
6355 | */ | |
6356 | void zone_pcp_disable(struct zone *zone) | |
6357 | { | |
6358 | mutex_lock(&pcp_batch_high_lock); | |
6359 | __zone_set_pageset_high_and_batch(zone, 0, 1); | |
6360 | __drain_all_pages(zone, true); | |
6361 | } | |
6362 | ||
6363 | void zone_pcp_enable(struct zone *zone) | |
6364 | { | |
6365 | __zone_set_pageset_high_and_batch(zone, zone->pageset_high, zone->pageset_batch); | |
6366 | mutex_unlock(&pcp_batch_high_lock); | |
6367 | } | |
6368 | ||
6369 | void zone_pcp_reset(struct zone *zone) | |
6370 | { | |
6371 | int cpu; | |
6372 | struct per_cpu_zonestat *pzstats; | |
6373 | ||
6374 | if (zone->per_cpu_pageset != &boot_pageset) { | |
6375 | for_each_online_cpu(cpu) { | |
6376 | pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); | |
6377 | drain_zonestat(zone, pzstats); | |
6378 | } | |
6379 | free_percpu(zone->per_cpu_pageset); | |
6380 | zone->per_cpu_pageset = &boot_pageset; | |
6381 | if (zone->per_cpu_zonestats != &boot_zonestats) { | |
6382 | free_percpu(zone->per_cpu_zonestats); | |
6383 | zone->per_cpu_zonestats = &boot_zonestats; | |
6384 | } | |
6385 | } | |
6386 | } | |
6387 | ||
6388 | #ifdef CONFIG_MEMORY_HOTREMOVE | |
6389 | /* | |
6390 | * All pages in the range must be in a single zone, must not contain holes, | |
6391 | * must span full sections, and must be isolated before calling this function. | |
6392 | */ | |
6393 | void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) | |
6394 | { | |
6395 | unsigned long pfn = start_pfn; | |
6396 | struct page *page; | |
6397 | struct zone *zone; | |
6398 | unsigned int order; | |
6399 | unsigned long flags; | |
6400 | ||
6401 | offline_mem_sections(pfn, end_pfn); | |
6402 | zone = page_zone(pfn_to_page(pfn)); | |
6403 | spin_lock_irqsave(&zone->lock, flags); | |
6404 | while (pfn < end_pfn) { | |
6405 | page = pfn_to_page(pfn); | |
6406 | /* | |
6407 | * The HWPoisoned page may be not in buddy system, and | |
6408 | * page_count() is not 0. | |
6409 | */ | |
6410 | if (unlikely(!PageBuddy(page) && PageHWPoison(page))) { | |
6411 | pfn++; | |
6412 | continue; | |
6413 | } | |
6414 | /* | |
6415 | * At this point all remaining PageOffline() pages have a | |
6416 | * reference count of 0 and can simply be skipped. | |
6417 | */ | |
6418 | if (PageOffline(page)) { | |
6419 | BUG_ON(page_count(page)); | |
6420 | BUG_ON(PageBuddy(page)); | |
6421 | pfn++; | |
6422 | continue; | |
6423 | } | |
6424 | ||
6425 | BUG_ON(page_count(page)); | |
6426 | BUG_ON(!PageBuddy(page)); | |
6427 | order = buddy_order(page); | |
6428 | del_page_from_free_list(page, zone, order); | |
6429 | pfn += (1 << order); | |
6430 | } | |
6431 | spin_unlock_irqrestore(&zone->lock, flags); | |
6432 | } | |
6433 | #endif | |
6434 | ||
6435 | /* | |
6436 | * This function returns a stable result only if called under zone lock. | |
6437 | */ | |
6438 | bool is_free_buddy_page(struct page *page) | |
6439 | { | |
6440 | unsigned long pfn = page_to_pfn(page); | |
6441 | unsigned int order; | |
6442 | ||
6443 | for (order = 0; order <= MAX_ORDER; order++) { | |
6444 | struct page *page_head = page - (pfn & ((1 << order) - 1)); | |
6445 | ||
6446 | if (PageBuddy(page_head) && | |
6447 | buddy_order_unsafe(page_head) >= order) | |
6448 | break; | |
6449 | } | |
6450 | ||
6451 | return order <= MAX_ORDER; | |
6452 | } | |
6453 | EXPORT_SYMBOL(is_free_buddy_page); | |
6454 | ||
6455 | #ifdef CONFIG_MEMORY_FAILURE | |
6456 | /* | |
6457 | * Break down a higher-order page in sub-pages, and keep our target out of | |
6458 | * buddy allocator. | |
6459 | */ | |
6460 | static void break_down_buddy_pages(struct zone *zone, struct page *page, | |
6461 | struct page *target, int low, int high, | |
6462 | int migratetype) | |
6463 | { | |
6464 | unsigned long size = 1 << high; | |
6465 | struct page *current_buddy, *next_page; | |
6466 | ||
6467 | while (high > low) { | |
6468 | high--; | |
6469 | size >>= 1; | |
6470 | ||
6471 | if (target >= &page[size]) { | |
6472 | next_page = page + size; | |
6473 | current_buddy = page; | |
6474 | } else { | |
6475 | next_page = page; | |
6476 | current_buddy = page + size; | |
6477 | } | |
6478 | ||
6479 | if (set_page_guard(zone, current_buddy, high, migratetype)) | |
6480 | continue; | |
6481 | ||
6482 | if (current_buddy != target) { | |
6483 | add_to_free_list(current_buddy, zone, high, migratetype); | |
6484 | set_buddy_order(current_buddy, high); | |
6485 | page = next_page; | |
6486 | } | |
6487 | } | |
6488 | } | |
6489 | ||
6490 | /* | |
6491 | * Take a page that will be marked as poisoned off the buddy allocator. | |
6492 | */ | |
6493 | bool take_page_off_buddy(struct page *page) | |
6494 | { | |
6495 | struct zone *zone = page_zone(page); | |
6496 | unsigned long pfn = page_to_pfn(page); | |
6497 | unsigned long flags; | |
6498 | unsigned int order; | |
6499 | bool ret = false; | |
6500 | ||
6501 | spin_lock_irqsave(&zone->lock, flags); | |
6502 | for (order = 0; order <= MAX_ORDER; order++) { | |
6503 | struct page *page_head = page - (pfn & ((1 << order) - 1)); | |
6504 | int page_order = buddy_order(page_head); | |
6505 | ||
6506 | if (PageBuddy(page_head) && page_order >= order) { | |
6507 | unsigned long pfn_head = page_to_pfn(page_head); | |
6508 | int migratetype = get_pfnblock_migratetype(page_head, | |
6509 | pfn_head); | |
6510 | ||
6511 | del_page_from_free_list(page_head, zone, page_order); | |
6512 | break_down_buddy_pages(zone, page_head, page, 0, | |
6513 | page_order, migratetype); | |
6514 | SetPageHWPoisonTakenOff(page); | |
6515 | if (!is_migrate_isolate(migratetype)) | |
6516 | __mod_zone_freepage_state(zone, -1, migratetype); | |
6517 | ret = true; | |
6518 | break; | |
6519 | } | |
6520 | if (page_count(page_head) > 0) | |
6521 | break; | |
6522 | } | |
6523 | spin_unlock_irqrestore(&zone->lock, flags); | |
6524 | return ret; | |
6525 | } | |
6526 | ||
6527 | /* | |
6528 | * Cancel takeoff done by take_page_off_buddy(). | |
6529 | */ | |
6530 | bool put_page_back_buddy(struct page *page) | |
6531 | { | |
6532 | struct zone *zone = page_zone(page); | |
6533 | unsigned long pfn = page_to_pfn(page); | |
6534 | unsigned long flags; | |
6535 | int migratetype = get_pfnblock_migratetype(page, pfn); | |
6536 | bool ret = false; | |
6537 | ||
6538 | spin_lock_irqsave(&zone->lock, flags); | |
6539 | if (put_page_testzero(page)) { | |
6540 | ClearPageHWPoisonTakenOff(page); | |
6541 | __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE); | |
6542 | if (TestClearPageHWPoison(page)) { | |
6543 | ret = true; | |
6544 | } | |
6545 | } | |
6546 | spin_unlock_irqrestore(&zone->lock, flags); | |
6547 | ||
6548 | return ret; | |
6549 | } | |
6550 | #endif | |
6551 | ||
6552 | #ifdef CONFIG_ZONE_DMA | |
6553 | bool has_managed_dma(void) | |
6554 | { | |
6555 | struct pglist_data *pgdat; | |
6556 | ||
6557 | for_each_online_pgdat(pgdat) { | |
6558 | struct zone *zone = &pgdat->node_zones[ZONE_DMA]; | |
6559 | ||
6560 | if (managed_zone(zone)) | |
6561 | return true; | |
6562 | } | |
6563 | return false; | |
6564 | } | |
6565 | #endif /* CONFIG_ZONE_DMA */ | |
6566 | ||
6567 | #ifdef CONFIG_UNACCEPTED_MEMORY | |
6568 | ||
6569 | /* Counts number of zones with unaccepted pages. */ | |
6570 | static DEFINE_STATIC_KEY_FALSE(zones_with_unaccepted_pages); | |
6571 | ||
6572 | static bool lazy_accept = true; | |
6573 | ||
6574 | static int __init accept_memory_parse(char *p) | |
6575 | { | |
6576 | if (!strcmp(p, "lazy")) { | |
6577 | lazy_accept = true; | |
6578 | return 0; | |
6579 | } else if (!strcmp(p, "eager")) { | |
6580 | lazy_accept = false; | |
6581 | return 0; | |
6582 | } else { | |
6583 | return -EINVAL; | |
6584 | } | |
6585 | } | |
6586 | early_param("accept_memory", accept_memory_parse); | |
6587 | ||
6588 | static bool page_contains_unaccepted(struct page *page, unsigned int order) | |
6589 | { | |
6590 | phys_addr_t start = page_to_phys(page); | |
6591 | phys_addr_t end = start + (PAGE_SIZE << order); | |
6592 | ||
6593 | return range_contains_unaccepted_memory(start, end); | |
6594 | } | |
6595 | ||
6596 | static void accept_page(struct page *page, unsigned int order) | |
6597 | { | |
6598 | phys_addr_t start = page_to_phys(page); | |
6599 | ||
6600 | accept_memory(start, start + (PAGE_SIZE << order)); | |
6601 | } | |
6602 | ||
6603 | static bool try_to_accept_memory_one(struct zone *zone) | |
6604 | { | |
6605 | unsigned long flags; | |
6606 | struct page *page; | |
6607 | bool last; | |
6608 | ||
6609 | if (list_empty(&zone->unaccepted_pages)) | |
6610 | return false; | |
6611 | ||
6612 | spin_lock_irqsave(&zone->lock, flags); | |
6613 | page = list_first_entry_or_null(&zone->unaccepted_pages, | |
6614 | struct page, lru); | |
6615 | if (!page) { | |
6616 | spin_unlock_irqrestore(&zone->lock, flags); | |
6617 | return false; | |
6618 | } | |
6619 | ||
6620 | list_del(&page->lru); | |
6621 | last = list_empty(&zone->unaccepted_pages); | |
6622 | ||
6623 | __mod_zone_freepage_state(zone, -MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE); | |
6624 | __mod_zone_page_state(zone, NR_UNACCEPTED, -MAX_ORDER_NR_PAGES); | |
6625 | spin_unlock_irqrestore(&zone->lock, flags); | |
6626 | ||
6627 | accept_page(page, MAX_ORDER); | |
6628 | ||
6629 | __free_pages_ok(page, MAX_ORDER, FPI_TO_TAIL); | |
6630 | ||
6631 | if (last) | |
6632 | static_branch_dec(&zones_with_unaccepted_pages); | |
6633 | ||
6634 | return true; | |
6635 | } | |
6636 | ||
6637 | static bool try_to_accept_memory(struct zone *zone, unsigned int order) | |
6638 | { | |
6639 | long to_accept; | |
6640 | int ret = false; | |
6641 | ||
6642 | /* How much to accept to get to high watermark? */ | |
6643 | to_accept = high_wmark_pages(zone) - | |
6644 | (zone_page_state(zone, NR_FREE_PAGES) - | |
6645 | __zone_watermark_unusable_free(zone, order, 0)); | |
6646 | ||
6647 | /* Accept at least one page */ | |
6648 | do { | |
6649 | if (!try_to_accept_memory_one(zone)) | |
6650 | break; | |
6651 | ret = true; | |
6652 | to_accept -= MAX_ORDER_NR_PAGES; | |
6653 | } while (to_accept > 0); | |
6654 | ||
6655 | return ret; | |
6656 | } | |
6657 | ||
6658 | static inline bool has_unaccepted_memory(void) | |
6659 | { | |
6660 | return static_branch_unlikely(&zones_with_unaccepted_pages); | |
6661 | } | |
6662 | ||
6663 | static bool __free_unaccepted(struct page *page) | |
6664 | { | |
6665 | struct zone *zone = page_zone(page); | |
6666 | unsigned long flags; | |
6667 | bool first = false; | |
6668 | ||
6669 | if (!lazy_accept) | |
6670 | return false; | |
6671 | ||
6672 | spin_lock_irqsave(&zone->lock, flags); | |
6673 | first = list_empty(&zone->unaccepted_pages); | |
6674 | list_add_tail(&page->lru, &zone->unaccepted_pages); | |
6675 | __mod_zone_freepage_state(zone, MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE); | |
6676 | __mod_zone_page_state(zone, NR_UNACCEPTED, MAX_ORDER_NR_PAGES); | |
6677 | spin_unlock_irqrestore(&zone->lock, flags); | |
6678 | ||
6679 | if (first) | |
6680 | static_branch_inc(&zones_with_unaccepted_pages); | |
6681 | ||
6682 | return true; | |
6683 | } | |
6684 | ||
6685 | #else | |
6686 | ||
6687 | static bool page_contains_unaccepted(struct page *page, unsigned int order) | |
6688 | { | |
6689 | return false; | |
6690 | } | |
6691 | ||
6692 | static void accept_page(struct page *page, unsigned int order) | |
6693 | { | |
6694 | } | |
6695 | ||
6696 | static bool try_to_accept_memory(struct zone *zone, unsigned int order) | |
6697 | { | |
6698 | return false; | |
6699 | } | |
6700 | ||
6701 | static inline bool has_unaccepted_memory(void) | |
6702 | { | |
6703 | return false; | |
6704 | } | |
6705 | ||
6706 | static bool __free_unaccepted(struct page *page) | |
6707 | { | |
6708 | BUILD_BUG(); | |
6709 | return false; | |
6710 | } | |
6711 | ||
6712 | #endif /* CONFIG_UNACCEPTED_MEMORY */ |