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20c8ccb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
71e3aac0 AA |
2 | /* |
3 | * Copyright (C) 2009 Red Hat, Inc. | |
71e3aac0 AA |
4 | */ |
5 | ||
ae3a8c1c AM |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | ||
71e3aac0 AA |
8 | #include <linux/mm.h> |
9 | #include <linux/sched.h> | |
f7ccbae4 | 10 | #include <linux/sched/coredump.h> |
6a3827d7 | 11 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
12 | #include <linux/highmem.h> |
13 | #include <linux/hugetlb.h> | |
14 | #include <linux/mmu_notifier.h> | |
15 | #include <linux/rmap.h> | |
16 | #include <linux/swap.h> | |
97ae1749 | 17 | #include <linux/shrinker.h> |
ba76149f | 18 | #include <linux/mm_inline.h> |
e9b61f19 | 19 | #include <linux/swapops.h> |
4897c765 | 20 | #include <linux/dax.h> |
ba76149f | 21 | #include <linux/khugepaged.h> |
878aee7d | 22 | #include <linux/freezer.h> |
f25748e3 | 23 | #include <linux/pfn_t.h> |
a664b2d8 | 24 | #include <linux/mman.h> |
3565fce3 | 25 | #include <linux/memremap.h> |
325adeb5 | 26 | #include <linux/pagemap.h> |
49071d43 | 27 | #include <linux/debugfs.h> |
4daae3b4 | 28 | #include <linux/migrate.h> |
43b5fbbd | 29 | #include <linux/hashtable.h> |
6b251fc9 | 30 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 31 | #include <linux/page_idle.h> |
baa355fd | 32 | #include <linux/shmem_fs.h> |
6b31d595 | 33 | #include <linux/oom.h> |
98fa15f3 | 34 | #include <linux/numa.h> |
f7da677b | 35 | #include <linux/page_owner.h> |
97ae1749 | 36 | |
71e3aac0 AA |
37 | #include <asm/tlb.h> |
38 | #include <asm/pgalloc.h> | |
39 | #include "internal.h" | |
40 | ||
ba76149f | 41 | /* |
b14d595a MD |
42 | * By default, transparent hugepage support is disabled in order to avoid |
43 | * risking an increased memory footprint for applications that are not | |
44 | * guaranteed to benefit from it. When transparent hugepage support is | |
45 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
46 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
47 | * for all hugepage allocations. | |
ba76149f | 48 | */ |
71e3aac0 | 49 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 50 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 51 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
52 | #endif |
53 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
54 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
55 | #endif | |
444eb2a4 | 56 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
57 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
58 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 59 | |
9a982250 | 60 | static struct shrinker deferred_split_shrinker; |
f000565a | 61 | |
97ae1749 | 62 | static atomic_t huge_zero_refcount; |
56873f43 | 63 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 64 | |
7635d9cb MH |
65 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
66 | { | |
c0630669 YS |
67 | /* The addr is used to check if the vma size fits */ |
68 | unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; | |
69 | ||
70 | if (!transhuge_vma_suitable(vma, addr)) | |
71 | return false; | |
7635d9cb MH |
72 | if (vma_is_anonymous(vma)) |
73 | return __transparent_hugepage_enabled(vma); | |
c0630669 YS |
74 | if (vma_is_shmem(vma)) |
75 | return shmem_huge_enabled(vma); | |
7635d9cb MH |
76 | |
77 | return false; | |
78 | } | |
79 | ||
6fcb52a5 | 80 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
81 | { |
82 | struct page *zero_page; | |
83 | retry: | |
84 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 85 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
86 | |
87 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 88 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
89 | if (!zero_page) { |
90 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 91 | return NULL; |
d8a8e1f0 KS |
92 | } |
93 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 94 | preempt_disable(); |
5918d10a | 95 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 96 | preempt_enable(); |
5ddacbe9 | 97 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
98 | goto retry; |
99 | } | |
100 | ||
101 | /* We take additional reference here. It will be put back by shrinker */ | |
102 | atomic_set(&huge_zero_refcount, 2); | |
103 | preempt_enable(); | |
4db0c3c2 | 104 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
105 | } |
106 | ||
6fcb52a5 | 107 | static void put_huge_zero_page(void) |
4a6c1297 | 108 | { |
97ae1749 KS |
109 | /* |
110 | * Counter should never go to zero here. Only shrinker can put | |
111 | * last reference. | |
112 | */ | |
113 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
114 | } |
115 | ||
6fcb52a5 AL |
116 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
117 | { | |
118 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
119 | return READ_ONCE(huge_zero_page); | |
120 | ||
121 | if (!get_huge_zero_page()) | |
122 | return NULL; | |
123 | ||
124 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
125 | put_huge_zero_page(); | |
126 | ||
127 | return READ_ONCE(huge_zero_page); | |
128 | } | |
129 | ||
130 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
131 | { | |
132 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
133 | put_huge_zero_page(); | |
134 | } | |
135 | ||
48896466 GC |
136 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
137 | struct shrink_control *sc) | |
4a6c1297 | 138 | { |
48896466 GC |
139 | /* we can free zero page only if last reference remains */ |
140 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
141 | } | |
97ae1749 | 142 | |
48896466 GC |
143 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
144 | struct shrink_control *sc) | |
145 | { | |
97ae1749 | 146 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
147 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
148 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 149 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 150 | return HPAGE_PMD_NR; |
97ae1749 KS |
151 | } |
152 | ||
153 | return 0; | |
4a6c1297 KS |
154 | } |
155 | ||
97ae1749 | 156 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
157 | .count_objects = shrink_huge_zero_page_count, |
158 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
159 | .seeks = DEFAULT_SEEKS, |
160 | }; | |
161 | ||
71e3aac0 | 162 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
163 | static ssize_t enabled_show(struct kobject *kobj, |
164 | struct kobj_attribute *attr, char *buf) | |
165 | { | |
444eb2a4 MG |
166 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
167 | return sprintf(buf, "[always] madvise never\n"); | |
168 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
169 | return sprintf(buf, "always [madvise] never\n"); | |
170 | else | |
171 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 172 | } |
444eb2a4 | 173 | |
71e3aac0 AA |
174 | static ssize_t enabled_store(struct kobject *kobj, |
175 | struct kobj_attribute *attr, | |
176 | const char *buf, size_t count) | |
177 | { | |
21440d7e | 178 | ssize_t ret = count; |
ba76149f | 179 | |
21440d7e DR |
180 | if (!memcmp("always", buf, |
181 | min(sizeof("always")-1, count))) { | |
182 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
183 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
184 | } else if (!memcmp("madvise", buf, | |
185 | min(sizeof("madvise")-1, count))) { | |
186 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
187 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
188 | } else if (!memcmp("never", buf, | |
189 | min(sizeof("never")-1, count))) { | |
190 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
191 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
192 | } else | |
193 | ret = -EINVAL; | |
ba76149f AA |
194 | |
195 | if (ret > 0) { | |
b46e756f | 196 | int err = start_stop_khugepaged(); |
ba76149f AA |
197 | if (err) |
198 | ret = err; | |
199 | } | |
ba76149f | 200 | return ret; |
71e3aac0 AA |
201 | } |
202 | static struct kobj_attribute enabled_attr = | |
203 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
204 | ||
b46e756f | 205 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
206 | struct kobj_attribute *attr, char *buf, |
207 | enum transparent_hugepage_flag flag) | |
208 | { | |
e27e6151 BH |
209 | return sprintf(buf, "%d\n", |
210 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 211 | } |
e27e6151 | 212 | |
b46e756f | 213 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
214 | struct kobj_attribute *attr, |
215 | const char *buf, size_t count, | |
216 | enum transparent_hugepage_flag flag) | |
217 | { | |
e27e6151 BH |
218 | unsigned long value; |
219 | int ret; | |
220 | ||
221 | ret = kstrtoul(buf, 10, &value); | |
222 | if (ret < 0) | |
223 | return ret; | |
224 | if (value > 1) | |
225 | return -EINVAL; | |
226 | ||
227 | if (value) | |
71e3aac0 | 228 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 229 | else |
71e3aac0 | 230 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
231 | |
232 | return count; | |
233 | } | |
234 | ||
71e3aac0 AA |
235 | static ssize_t defrag_show(struct kobject *kobj, |
236 | struct kobj_attribute *attr, char *buf) | |
237 | { | |
444eb2a4 | 238 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 239 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 240 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
241 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
242 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
243 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
244 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
245 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
246 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 247 | } |
21440d7e | 248 | |
71e3aac0 AA |
249 | static ssize_t defrag_store(struct kobject *kobj, |
250 | struct kobj_attribute *attr, | |
251 | const char *buf, size_t count) | |
252 | { | |
21440d7e DR |
253 | if (!memcmp("always", buf, |
254 | min(sizeof("always")-1, count))) { | |
255 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
256 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
257 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
258 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
259 | } else if (!memcmp("defer+madvise", buf, |
260 | min(sizeof("defer+madvise")-1, count))) { | |
261 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
262 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
263 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
264 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
4fad7fb6 DR |
265 | } else if (!memcmp("defer", buf, |
266 | min(sizeof("defer")-1, count))) { | |
267 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
268 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
269 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
270 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
271 | } else if (!memcmp("madvise", buf, |
272 | min(sizeof("madvise")-1, count))) { | |
273 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
274 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
275 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
276 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
277 | } else if (!memcmp("never", buf, | |
278 | min(sizeof("never")-1, count))) { | |
279 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
280 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
281 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
282 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
283 | } else | |
284 | return -EINVAL; | |
285 | ||
286 | return count; | |
71e3aac0 AA |
287 | } |
288 | static struct kobj_attribute defrag_attr = | |
289 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
290 | ||
79da5407 KS |
291 | static ssize_t use_zero_page_show(struct kobject *kobj, |
292 | struct kobj_attribute *attr, char *buf) | |
293 | { | |
b46e756f | 294 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
295 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
296 | } | |
297 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
298 | struct kobj_attribute *attr, const char *buf, size_t count) | |
299 | { | |
b46e756f | 300 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
301 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
302 | } | |
303 | static struct kobj_attribute use_zero_page_attr = | |
304 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
305 | |
306 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
307 | struct kobj_attribute *attr, char *buf) | |
308 | { | |
309 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
310 | } | |
311 | static struct kobj_attribute hpage_pmd_size_attr = | |
312 | __ATTR_RO(hpage_pmd_size); | |
313 | ||
71e3aac0 AA |
314 | #ifdef CONFIG_DEBUG_VM |
315 | static ssize_t debug_cow_show(struct kobject *kobj, | |
316 | struct kobj_attribute *attr, char *buf) | |
317 | { | |
b46e756f | 318 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
319 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
320 | } | |
321 | static ssize_t debug_cow_store(struct kobject *kobj, | |
322 | struct kobj_attribute *attr, | |
323 | const char *buf, size_t count) | |
324 | { | |
b46e756f | 325 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
326 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
327 | } | |
328 | static struct kobj_attribute debug_cow_attr = | |
329 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
330 | #endif /* CONFIG_DEBUG_VM */ | |
331 | ||
332 | static struct attribute *hugepage_attr[] = { | |
333 | &enabled_attr.attr, | |
334 | &defrag_attr.attr, | |
79da5407 | 335 | &use_zero_page_attr.attr, |
49920d28 | 336 | &hpage_pmd_size_attr.attr, |
e496cf3d | 337 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
338 | &shmem_enabled_attr.attr, |
339 | #endif | |
71e3aac0 AA |
340 | #ifdef CONFIG_DEBUG_VM |
341 | &debug_cow_attr.attr, | |
342 | #endif | |
343 | NULL, | |
344 | }; | |
345 | ||
8aa95a21 | 346 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 347 | .attrs = hugepage_attr, |
ba76149f AA |
348 | }; |
349 | ||
569e5590 | 350 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 351 | { |
71e3aac0 AA |
352 | int err; |
353 | ||
569e5590 SL |
354 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
355 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 356 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 357 | return -ENOMEM; |
ba76149f AA |
358 | } |
359 | ||
569e5590 | 360 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 361 | if (err) { |
ae3a8c1c | 362 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 363 | goto delete_obj; |
ba76149f AA |
364 | } |
365 | ||
569e5590 | 366 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 367 | if (err) { |
ae3a8c1c | 368 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 369 | goto remove_hp_group; |
ba76149f | 370 | } |
569e5590 SL |
371 | |
372 | return 0; | |
373 | ||
374 | remove_hp_group: | |
375 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
376 | delete_obj: | |
377 | kobject_put(*hugepage_kobj); | |
378 | return err; | |
379 | } | |
380 | ||
381 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
382 | { | |
383 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
384 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
385 | kobject_put(hugepage_kobj); | |
386 | } | |
387 | #else | |
388 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
389 | { | |
390 | return 0; | |
391 | } | |
392 | ||
393 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
394 | { | |
395 | } | |
396 | #endif /* CONFIG_SYSFS */ | |
397 | ||
398 | static int __init hugepage_init(void) | |
399 | { | |
400 | int err; | |
401 | struct kobject *hugepage_kobj; | |
402 | ||
403 | if (!has_transparent_hugepage()) { | |
404 | transparent_hugepage_flags = 0; | |
405 | return -EINVAL; | |
406 | } | |
407 | ||
ff20c2e0 KS |
408 | /* |
409 | * hugepages can't be allocated by the buddy allocator | |
410 | */ | |
411 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
412 | /* | |
413 | * we use page->mapping and page->index in second tail page | |
414 | * as list_head: assuming THP order >= 2 | |
415 | */ | |
416 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
417 | ||
569e5590 SL |
418 | err = hugepage_init_sysfs(&hugepage_kobj); |
419 | if (err) | |
65ebb64f | 420 | goto err_sysfs; |
ba76149f | 421 | |
b46e756f | 422 | err = khugepaged_init(); |
ba76149f | 423 | if (err) |
65ebb64f | 424 | goto err_slab; |
ba76149f | 425 | |
65ebb64f KS |
426 | err = register_shrinker(&huge_zero_page_shrinker); |
427 | if (err) | |
428 | goto err_hzp_shrinker; | |
9a982250 KS |
429 | err = register_shrinker(&deferred_split_shrinker); |
430 | if (err) | |
431 | goto err_split_shrinker; | |
97ae1749 | 432 | |
97562cd2 RR |
433 | /* |
434 | * By default disable transparent hugepages on smaller systems, | |
435 | * where the extra memory used could hurt more than TLB overhead | |
436 | * is likely to save. The admin can still enable it through /sys. | |
437 | */ | |
ca79b0c2 | 438 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 439 | transparent_hugepage_flags = 0; |
79553da2 KS |
440 | return 0; |
441 | } | |
97562cd2 | 442 | |
79553da2 | 443 | err = start_stop_khugepaged(); |
65ebb64f KS |
444 | if (err) |
445 | goto err_khugepaged; | |
ba76149f | 446 | |
569e5590 | 447 | return 0; |
65ebb64f | 448 | err_khugepaged: |
9a982250 KS |
449 | unregister_shrinker(&deferred_split_shrinker); |
450 | err_split_shrinker: | |
65ebb64f KS |
451 | unregister_shrinker(&huge_zero_page_shrinker); |
452 | err_hzp_shrinker: | |
b46e756f | 453 | khugepaged_destroy(); |
65ebb64f | 454 | err_slab: |
569e5590 | 455 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 456 | err_sysfs: |
ba76149f | 457 | return err; |
71e3aac0 | 458 | } |
a64fb3cd | 459 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
460 | |
461 | static int __init setup_transparent_hugepage(char *str) | |
462 | { | |
463 | int ret = 0; | |
464 | if (!str) | |
465 | goto out; | |
466 | if (!strcmp(str, "always")) { | |
467 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
468 | &transparent_hugepage_flags); | |
469 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
470 | &transparent_hugepage_flags); | |
471 | ret = 1; | |
472 | } else if (!strcmp(str, "madvise")) { | |
473 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
474 | &transparent_hugepage_flags); | |
475 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
476 | &transparent_hugepage_flags); | |
477 | ret = 1; | |
478 | } else if (!strcmp(str, "never")) { | |
479 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
480 | &transparent_hugepage_flags); | |
481 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
482 | &transparent_hugepage_flags); | |
483 | ret = 1; | |
484 | } | |
485 | out: | |
486 | if (!ret) | |
ae3a8c1c | 487 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
488 | return ret; |
489 | } | |
490 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
491 | ||
f55e1014 | 492 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 493 | { |
f55e1014 | 494 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
495 | pmd = pmd_mkwrite(pmd); |
496 | return pmd; | |
497 | } | |
498 | ||
9a982250 KS |
499 | static inline struct list_head *page_deferred_list(struct page *page) |
500 | { | |
fa3015b7 MW |
501 | /* ->lru in the tail pages is occupied by compound_head. */ |
502 | return &page[2].deferred_list; | |
9a982250 KS |
503 | } |
504 | ||
505 | void prep_transhuge_page(struct page *page) | |
506 | { | |
507 | /* | |
508 | * we use page->mapping and page->indexlru in second tail page | |
509 | * as list_head: assuming THP order >= 2 | |
510 | */ | |
9a982250 KS |
511 | |
512 | INIT_LIST_HEAD(page_deferred_list(page)); | |
513 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
514 | } | |
515 | ||
b3b07077 | 516 | static unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
74d2fad1 TK |
517 | loff_t off, unsigned long flags, unsigned long size) |
518 | { | |
519 | unsigned long addr; | |
520 | loff_t off_end = off + len; | |
521 | loff_t off_align = round_up(off, size); | |
522 | unsigned long len_pad; | |
523 | ||
524 | if (off_end <= off_align || (off_end - off_align) < size) | |
525 | return 0; | |
526 | ||
527 | len_pad = len + size; | |
528 | if (len_pad < len || (off + len_pad) < off) | |
529 | return 0; | |
530 | ||
531 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
532 | off >> PAGE_SHIFT, flags); | |
533 | if (IS_ERR_VALUE(addr)) | |
534 | return 0; | |
535 | ||
536 | addr += (off - addr) & (size - 1); | |
537 | return addr; | |
538 | } | |
539 | ||
540 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
541 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
542 | { | |
543 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
544 | ||
545 | if (addr) | |
546 | goto out; | |
547 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
548 | goto out; | |
549 | ||
550 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
551 | if (addr) | |
552 | return addr; | |
553 | ||
554 | out: | |
555 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
556 | } | |
557 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
558 | ||
2b740303 SJ |
559 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
560 | struct page *page, gfp_t gfp) | |
71e3aac0 | 561 | { |
82b0f8c3 | 562 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 563 | struct mem_cgroup *memcg; |
71e3aac0 | 564 | pgtable_t pgtable; |
82b0f8c3 | 565 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 566 | vm_fault_t ret = 0; |
71e3aac0 | 567 | |
309381fe | 568 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 569 | |
2cf85583 | 570 | if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
571 | put_page(page); |
572 | count_vm_event(THP_FAULT_FALLBACK); | |
573 | return VM_FAULT_FALLBACK; | |
574 | } | |
00501b53 | 575 | |
4cf58924 | 576 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 577 | if (unlikely(!pgtable)) { |
6b31d595 MH |
578 | ret = VM_FAULT_OOM; |
579 | goto release; | |
00501b53 | 580 | } |
71e3aac0 | 581 | |
c79b57e4 | 582 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
583 | /* |
584 | * The memory barrier inside __SetPageUptodate makes sure that | |
585 | * clear_huge_page writes become visible before the set_pmd_at() | |
586 | * write. | |
587 | */ | |
71e3aac0 AA |
588 | __SetPageUptodate(page); |
589 | ||
82b0f8c3 JK |
590 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
591 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 592 | goto unlock_release; |
71e3aac0 AA |
593 | } else { |
594 | pmd_t entry; | |
6b251fc9 | 595 | |
6b31d595 MH |
596 | ret = check_stable_address_space(vma->vm_mm); |
597 | if (ret) | |
598 | goto unlock_release; | |
599 | ||
6b251fc9 AA |
600 | /* Deliver the page fault to userland */ |
601 | if (userfaultfd_missing(vma)) { | |
2b740303 | 602 | vm_fault_t ret2; |
6b251fc9 | 603 | |
82b0f8c3 | 604 | spin_unlock(vmf->ptl); |
f627c2f5 | 605 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 606 | put_page(page); |
bae473a4 | 607 | pte_free(vma->vm_mm, pgtable); |
2b740303 SJ |
608 | ret2 = handle_userfault(vmf, VM_UFFD_MISSING); |
609 | VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); | |
610 | return ret2; | |
6b251fc9 AA |
611 | } |
612 | ||
3122359a | 613 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 614 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 615 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 616 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 617 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
618 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
619 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 620 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 621 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 622 | spin_unlock(vmf->ptl); |
6b251fc9 | 623 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 624 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
71e3aac0 AA |
625 | } |
626 | ||
aa2e878e | 627 | return 0; |
6b31d595 MH |
628 | unlock_release: |
629 | spin_unlock(vmf->ptl); | |
630 | release: | |
631 | if (pgtable) | |
632 | pte_free(vma->vm_mm, pgtable); | |
633 | mem_cgroup_cancel_charge(page, memcg, true); | |
634 | put_page(page); | |
635 | return ret; | |
636 | ||
71e3aac0 AA |
637 | } |
638 | ||
444eb2a4 | 639 | /* |
21440d7e DR |
640 | * always: directly stall for all thp allocations |
641 | * defer: wake kswapd and fail if not immediately available | |
642 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
643 | * fail if not immediately available | |
644 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
645 | * available | |
646 | * never: never stall for any thp allocation | |
444eb2a4 | 647 | */ |
92717d42 | 648 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma, unsigned long addr) |
444eb2a4 | 649 | { |
21440d7e | 650 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
ac79f78d | 651 | const gfp_t gfp_mask = GFP_TRANSHUGE_LIGHT | __GFP_THISNODE; |
2f0799a0 | 652 | |
ac79f78d | 653 | /* Always do synchronous compaction */ |
a8282608 | 654 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
ac79f78d DR |
655 | return GFP_TRANSHUGE | __GFP_THISNODE | |
656 | (vma_madvised ? 0 : __GFP_NORETRY); | |
657 | ||
658 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 659 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
ac79f78d DR |
660 | return gfp_mask | __GFP_KSWAPD_RECLAIM; |
661 | ||
662 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 663 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
ac79f78d DR |
664 | return gfp_mask | (vma_madvised ? __GFP_DIRECT_RECLAIM : |
665 | __GFP_KSWAPD_RECLAIM); | |
666 | ||
667 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 668 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
ac79f78d DR |
669 | return gfp_mask | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); |
670 | ||
671 | return gfp_mask; | |
444eb2a4 MG |
672 | } |
673 | ||
c4088ebd | 674 | /* Caller must hold page table lock. */ |
d295e341 | 675 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 676 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 677 | struct page *zero_page) |
fc9fe822 KS |
678 | { |
679 | pmd_t entry; | |
7c414164 AM |
680 | if (!pmd_none(*pmd)) |
681 | return false; | |
5918d10a | 682 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 683 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
684 | if (pgtable) |
685 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 686 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 687 | mm_inc_nr_ptes(mm); |
7c414164 | 688 | return true; |
fc9fe822 KS |
689 | } |
690 | ||
2b740303 | 691 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 692 | { |
82b0f8c3 | 693 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 694 | gfp_t gfp; |
71e3aac0 | 695 | struct page *page; |
82b0f8c3 | 696 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 697 | |
43675e6f | 698 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 699 | return VM_FAULT_FALLBACK; |
128ec037 KS |
700 | if (unlikely(anon_vma_prepare(vma))) |
701 | return VM_FAULT_OOM; | |
6d50e60c | 702 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 703 | return VM_FAULT_OOM; |
82b0f8c3 | 704 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 705 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
706 | transparent_hugepage_use_zero_page()) { |
707 | pgtable_t pgtable; | |
708 | struct page *zero_page; | |
709 | bool set; | |
2b740303 | 710 | vm_fault_t ret; |
4cf58924 | 711 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 712 | if (unlikely(!pgtable)) |
ba76149f | 713 | return VM_FAULT_OOM; |
6fcb52a5 | 714 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 715 | if (unlikely(!zero_page)) { |
bae473a4 | 716 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 717 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 718 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 719 | } |
82b0f8c3 | 720 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
721 | ret = 0; |
722 | set = false; | |
82b0f8c3 | 723 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
724 | ret = check_stable_address_space(vma->vm_mm); |
725 | if (ret) { | |
726 | spin_unlock(vmf->ptl); | |
727 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
728 | spin_unlock(vmf->ptl); |
729 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
730 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
731 | } else { | |
bae473a4 | 732 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
733 | haddr, vmf->pmd, zero_page); |
734 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
735 | set = true; |
736 | } | |
737 | } else | |
82b0f8c3 | 738 | spin_unlock(vmf->ptl); |
6fcb52a5 | 739 | if (!set) |
bae473a4 | 740 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 741 | return ret; |
71e3aac0 | 742 | } |
92717d42 AA |
743 | gfp = alloc_hugepage_direct_gfpmask(vma, haddr); |
744 | page = alloc_pages_vma(gfp, HPAGE_PMD_ORDER, vma, haddr, numa_node_id()); | |
128ec037 KS |
745 | if (unlikely(!page)) { |
746 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 747 | return VM_FAULT_FALLBACK; |
128ec037 | 748 | } |
9a982250 | 749 | prep_transhuge_page(page); |
82b0f8c3 | 750 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
751 | } |
752 | ||
ae18d6dc | 753 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
754 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
755 | pgtable_t pgtable) | |
5cad465d MW |
756 | { |
757 | struct mm_struct *mm = vma->vm_mm; | |
758 | pmd_t entry; | |
759 | spinlock_t *ptl; | |
760 | ||
761 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
762 | if (!pmd_none(*pmd)) { |
763 | if (write) { | |
764 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
765 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
766 | goto out_unlock; | |
767 | } | |
768 | entry = pmd_mkyoung(*pmd); | |
769 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
770 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
771 | update_mmu_cache_pmd(vma, addr, pmd); | |
772 | } | |
773 | ||
774 | goto out_unlock; | |
775 | } | |
776 | ||
f25748e3 DW |
777 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
778 | if (pfn_t_devmap(pfn)) | |
779 | entry = pmd_mkdevmap(entry); | |
01871e59 | 780 | if (write) { |
f55e1014 LT |
781 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
782 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 783 | } |
3b6521f5 OH |
784 | |
785 | if (pgtable) { | |
786 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 787 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 788 | pgtable = NULL; |
3b6521f5 OH |
789 | } |
790 | ||
01871e59 RZ |
791 | set_pmd_at(mm, addr, pmd, entry); |
792 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
793 | |
794 | out_unlock: | |
5cad465d | 795 | spin_unlock(ptl); |
c6f3c5ee AK |
796 | if (pgtable) |
797 | pte_free(mm, pgtable); | |
5cad465d MW |
798 | } |
799 | ||
fce86ff5 | 800 | vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) |
5cad465d | 801 | { |
fce86ff5 DW |
802 | unsigned long addr = vmf->address & PMD_MASK; |
803 | struct vm_area_struct *vma = vmf->vma; | |
5cad465d | 804 | pgprot_t pgprot = vma->vm_page_prot; |
3b6521f5 | 805 | pgtable_t pgtable = NULL; |
fce86ff5 | 806 | |
5cad465d MW |
807 | /* |
808 | * If we had pmd_special, we could avoid all these restrictions, | |
809 | * but we need to be consistent with PTEs and architectures that | |
810 | * can't support a 'special' bit. | |
811 | */ | |
e1fb4a08 DJ |
812 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
813 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
814 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
815 | (VM_PFNMAP|VM_MIXEDMAP)); | |
816 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
817 | |
818 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
819 | return VM_FAULT_SIGBUS; | |
308a047c | 820 | |
3b6521f5 | 821 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 822 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
823 | if (!pgtable) |
824 | return VM_FAULT_OOM; | |
825 | } | |
826 | ||
308a047c BP |
827 | track_pfn_insert(vma, &pgprot, pfn); |
828 | ||
fce86ff5 | 829 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 830 | return VM_FAULT_NOPAGE; |
5cad465d | 831 | } |
dee41079 | 832 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 833 | |
a00cc7d9 | 834 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 835 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 836 | { |
f55e1014 | 837 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
838 | pud = pud_mkwrite(pud); |
839 | return pud; | |
840 | } | |
841 | ||
842 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
843 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
844 | { | |
845 | struct mm_struct *mm = vma->vm_mm; | |
846 | pud_t entry; | |
847 | spinlock_t *ptl; | |
848 | ||
849 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
850 | if (!pud_none(*pud)) { |
851 | if (write) { | |
852 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
853 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
854 | goto out_unlock; | |
855 | } | |
856 | entry = pud_mkyoung(*pud); | |
857 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
858 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
859 | update_mmu_cache_pud(vma, addr, pud); | |
860 | } | |
861 | goto out_unlock; | |
862 | } | |
863 | ||
a00cc7d9 MW |
864 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
865 | if (pfn_t_devmap(pfn)) | |
866 | entry = pud_mkdevmap(entry); | |
867 | if (write) { | |
f55e1014 LT |
868 | entry = pud_mkyoung(pud_mkdirty(entry)); |
869 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
870 | } |
871 | set_pud_at(mm, addr, pud, entry); | |
872 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
873 | |
874 | out_unlock: | |
a00cc7d9 MW |
875 | spin_unlock(ptl); |
876 | } | |
877 | ||
fce86ff5 | 878 | vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) |
a00cc7d9 | 879 | { |
fce86ff5 DW |
880 | unsigned long addr = vmf->address & PUD_MASK; |
881 | struct vm_area_struct *vma = vmf->vma; | |
a00cc7d9 | 882 | pgprot_t pgprot = vma->vm_page_prot; |
fce86ff5 | 883 | |
a00cc7d9 MW |
884 | /* |
885 | * If we had pud_special, we could avoid all these restrictions, | |
886 | * but we need to be consistent with PTEs and architectures that | |
887 | * can't support a 'special' bit. | |
888 | */ | |
62ec0d8c DJ |
889 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
890 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
891 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
892 | (VM_PFNMAP|VM_MIXEDMAP)); | |
893 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
894 | |
895 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
896 | return VM_FAULT_SIGBUS; | |
897 | ||
898 | track_pfn_insert(vma, &pgprot, pfn); | |
899 | ||
fce86ff5 | 900 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
901 | return VM_FAULT_NOPAGE; |
902 | } | |
903 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
904 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
905 | ||
3565fce3 | 906 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 907 | pmd_t *pmd, int flags) |
3565fce3 DW |
908 | { |
909 | pmd_t _pmd; | |
910 | ||
a8f97366 KS |
911 | _pmd = pmd_mkyoung(*pmd); |
912 | if (flags & FOLL_WRITE) | |
913 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 914 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 915 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
916 | update_mmu_cache_pmd(vma, addr, pmd); |
917 | } | |
918 | ||
919 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 920 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
921 | { |
922 | unsigned long pfn = pmd_pfn(*pmd); | |
923 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
924 | struct page *page; |
925 | ||
926 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
927 | ||
8310d48b KF |
928 | /* |
929 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
930 | * not be in this function with `flags & FOLL_COW` set. | |
931 | */ | |
932 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
933 | ||
f6f37321 | 934 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
935 | return NULL; |
936 | ||
937 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
938 | /* pass */; | |
939 | else | |
940 | return NULL; | |
941 | ||
942 | if (flags & FOLL_TOUCH) | |
a8f97366 | 943 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
944 | |
945 | /* | |
946 | * device mapped pages can only be returned if the | |
947 | * caller will manage the page reference count. | |
948 | */ | |
949 | if (!(flags & FOLL_GET)) | |
950 | return ERR_PTR(-EEXIST); | |
951 | ||
952 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
953 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
954 | if (!*pgmap) | |
3565fce3 DW |
955 | return ERR_PTR(-EFAULT); |
956 | page = pfn_to_page(pfn); | |
957 | get_page(page); | |
3565fce3 DW |
958 | |
959 | return page; | |
960 | } | |
961 | ||
71e3aac0 AA |
962 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
963 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
964 | struct vm_area_struct *vma) | |
965 | { | |
c4088ebd | 966 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
967 | struct page *src_page; |
968 | pmd_t pmd; | |
12c9d70b | 969 | pgtable_t pgtable = NULL; |
628d47ce | 970 | int ret = -ENOMEM; |
71e3aac0 | 971 | |
628d47ce KS |
972 | /* Skip if can be re-fill on fault */ |
973 | if (!vma_is_anonymous(vma)) | |
974 | return 0; | |
975 | ||
4cf58924 | 976 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
977 | if (unlikely(!pgtable)) |
978 | goto out; | |
71e3aac0 | 979 | |
c4088ebd KS |
980 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
981 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
982 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
983 | |
984 | ret = -EAGAIN; | |
985 | pmd = *src_pmd; | |
84c3fc4e ZY |
986 | |
987 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
988 | if (unlikely(is_swap_pmd(pmd))) { | |
989 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
990 | ||
991 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
992 | if (is_write_migration_entry(entry)) { | |
993 | make_migration_entry_read(&entry); | |
994 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
995 | if (pmd_swp_soft_dirty(*src_pmd)) |
996 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
997 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
998 | } | |
dd8a67f9 | 999 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1000 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1001 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
1002 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1003 | ret = 0; | |
1004 | goto out_unlock; | |
1005 | } | |
1006 | #endif | |
1007 | ||
628d47ce | 1008 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1009 | pte_free(dst_mm, pgtable); |
1010 | goto out_unlock; | |
1011 | } | |
fc9fe822 | 1012 | /* |
c4088ebd | 1013 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1014 | * under splitting since we don't split the page itself, only pmd to |
1015 | * a page table. | |
1016 | */ | |
1017 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 1018 | struct page *zero_page; |
97ae1749 KS |
1019 | /* |
1020 | * get_huge_zero_page() will never allocate a new page here, | |
1021 | * since we already have a zero page to copy. It just takes a | |
1022 | * reference. | |
1023 | */ | |
6fcb52a5 | 1024 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 1025 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 1026 | zero_page); |
fc9fe822 KS |
1027 | ret = 0; |
1028 | goto out_unlock; | |
1029 | } | |
de466bd6 | 1030 | |
628d47ce KS |
1031 | src_page = pmd_page(pmd); |
1032 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
1033 | get_page(src_page); | |
1034 | page_dup_rmap(src_page, true); | |
1035 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 1036 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1037 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
1038 | |
1039 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
1040 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
1041 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1042 | |
1043 | ret = 0; | |
1044 | out_unlock: | |
c4088ebd KS |
1045 | spin_unlock(src_ptl); |
1046 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1047 | out: |
1048 | return ret; | |
1049 | } | |
1050 | ||
a00cc7d9 MW |
1051 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1052 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1053 | pud_t *pud, int flags) |
a00cc7d9 MW |
1054 | { |
1055 | pud_t _pud; | |
1056 | ||
a8f97366 KS |
1057 | _pud = pud_mkyoung(*pud); |
1058 | if (flags & FOLL_WRITE) | |
1059 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1060 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1061 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1062 | update_mmu_cache_pud(vma, addr, pud); |
1063 | } | |
1064 | ||
1065 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1066 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1067 | { |
1068 | unsigned long pfn = pud_pfn(*pud); | |
1069 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1070 | struct page *page; |
1071 | ||
1072 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1073 | ||
f6f37321 | 1074 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1075 | return NULL; |
1076 | ||
1077 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1078 | /* pass */; | |
1079 | else | |
1080 | return NULL; | |
1081 | ||
1082 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1083 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1084 | |
1085 | /* | |
1086 | * device mapped pages can only be returned if the | |
1087 | * caller will manage the page reference count. | |
1088 | */ | |
1089 | if (!(flags & FOLL_GET)) | |
1090 | return ERR_PTR(-EEXIST); | |
1091 | ||
1092 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1093 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1094 | if (!*pgmap) | |
a00cc7d9 MW |
1095 | return ERR_PTR(-EFAULT); |
1096 | page = pfn_to_page(pfn); | |
1097 | get_page(page); | |
a00cc7d9 MW |
1098 | |
1099 | return page; | |
1100 | } | |
1101 | ||
1102 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1103 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1104 | struct vm_area_struct *vma) | |
1105 | { | |
1106 | spinlock_t *dst_ptl, *src_ptl; | |
1107 | pud_t pud; | |
1108 | int ret; | |
1109 | ||
1110 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1111 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1112 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1113 | ||
1114 | ret = -EAGAIN; | |
1115 | pud = *src_pud; | |
1116 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1117 | goto out_unlock; | |
1118 | ||
1119 | /* | |
1120 | * When page table lock is held, the huge zero pud should not be | |
1121 | * under splitting since we don't split the page itself, only pud to | |
1122 | * a page table. | |
1123 | */ | |
1124 | if (is_huge_zero_pud(pud)) { | |
1125 | /* No huge zero pud yet */ | |
1126 | } | |
1127 | ||
1128 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1129 | pud = pud_mkold(pud_wrprotect(pud)); | |
1130 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1131 | ||
1132 | ret = 0; | |
1133 | out_unlock: | |
1134 | spin_unlock(src_ptl); | |
1135 | spin_unlock(dst_ptl); | |
1136 | return ret; | |
1137 | } | |
1138 | ||
1139 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1140 | { | |
1141 | pud_t entry; | |
1142 | unsigned long haddr; | |
1143 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1144 | ||
1145 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1146 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1147 | goto unlock; | |
1148 | ||
1149 | entry = pud_mkyoung(orig_pud); | |
1150 | if (write) | |
1151 | entry = pud_mkdirty(entry); | |
1152 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1153 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1154 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1155 | ||
1156 | unlock: | |
1157 | spin_unlock(vmf->ptl); | |
1158 | } | |
1159 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1160 | ||
82b0f8c3 | 1161 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1162 | { |
1163 | pmd_t entry; | |
1164 | unsigned long haddr; | |
20f664aa | 1165 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1166 | |
82b0f8c3 JK |
1167 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1168 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1169 | goto unlock; |
1170 | ||
1171 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1172 | if (write) |
1173 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1174 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1175 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1176 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1177 | |
1178 | unlock: | |
82b0f8c3 | 1179 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1180 | } |
1181 | ||
2b740303 SJ |
1182 | static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, |
1183 | pmd_t orig_pmd, struct page *page) | |
71e3aac0 | 1184 | { |
82b0f8c3 JK |
1185 | struct vm_area_struct *vma = vmf->vma; |
1186 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1187 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1188 | pgtable_t pgtable; |
1189 | pmd_t _pmd; | |
2b740303 SJ |
1190 | int i; |
1191 | vm_fault_t ret = 0; | |
71e3aac0 | 1192 | struct page **pages; |
ac46d4f3 | 1193 | struct mmu_notifier_range range; |
71e3aac0 | 1194 | |
6da2ec56 KC |
1195 | pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), |
1196 | GFP_KERNEL); | |
71e3aac0 AA |
1197 | if (unlikely(!pages)) { |
1198 | ret |= VM_FAULT_OOM; | |
1199 | goto out; | |
1200 | } | |
1201 | ||
1202 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1203 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1204 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1205 | if (unlikely(!pages[i] || |
2cf85583 | 1206 | mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, |
bae473a4 | 1207 | GFP_KERNEL, &memcg, false))) { |
b9bbfbe3 | 1208 | if (pages[i]) |
71e3aac0 | 1209 | put_page(pages[i]); |
b9bbfbe3 | 1210 | while (--i >= 0) { |
00501b53 JW |
1211 | memcg = (void *)page_private(pages[i]); |
1212 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1213 | mem_cgroup_cancel_charge(pages[i], memcg, |
1214 | false); | |
b9bbfbe3 AA |
1215 | put_page(pages[i]); |
1216 | } | |
71e3aac0 AA |
1217 | kfree(pages); |
1218 | ret |= VM_FAULT_OOM; | |
1219 | goto out; | |
1220 | } | |
00501b53 | 1221 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1222 | } |
1223 | ||
1224 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1225 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1226 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1227 | __SetPageUptodate(pages[i]); |
1228 | cond_resched(); | |
1229 | } | |
1230 | ||
7269f999 JG |
1231 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1232 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1233 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1234 | |
82b0f8c3 JK |
1235 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1236 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1237 | goto out_free_pages; |
309381fe | 1238 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1239 | |
0f10851e JG |
1240 | /* |
1241 | * Leave pmd empty until pte is filled note we must notify here as | |
1242 | * concurrent CPU thread might write to new page before the call to | |
1243 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1244 | * device seeing memory write in different order than CPU. | |
1245 | * | |
ad56b738 | 1246 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 1247 | */ |
82b0f8c3 | 1248 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1249 | |
82b0f8c3 | 1250 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1251 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1252 | |
1253 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1254 | pte_t entry; |
71e3aac0 AA |
1255 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1256 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1257 | memcg = (void *)page_private(pages[i]); |
1258 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1259 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1260 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1261 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1262 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1263 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1264 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1265 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1266 | } |
1267 | kfree(pages); | |
1268 | ||
71e3aac0 | 1269 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1270 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1271 | page_remove_rmap(page, true); |
82b0f8c3 | 1272 | spin_unlock(vmf->ptl); |
71e3aac0 | 1273 | |
4645b9fe JG |
1274 | /* |
1275 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1276 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1277 | */ | |
ac46d4f3 | 1278 | mmu_notifier_invalidate_range_only_end(&range); |
2ec74c3e | 1279 | |
71e3aac0 AA |
1280 | ret |= VM_FAULT_WRITE; |
1281 | put_page(page); | |
1282 | ||
1283 | out: | |
1284 | return ret; | |
1285 | ||
1286 | out_free_pages: | |
82b0f8c3 | 1287 | spin_unlock(vmf->ptl); |
ac46d4f3 | 1288 | mmu_notifier_invalidate_range_end(&range); |
b9bbfbe3 | 1289 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1290 | memcg = (void *)page_private(pages[i]); |
1291 | set_page_private(pages[i], 0); | |
f627c2f5 | 1292 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1293 | put_page(pages[i]); |
b9bbfbe3 | 1294 | } |
71e3aac0 AA |
1295 | kfree(pages); |
1296 | goto out; | |
1297 | } | |
1298 | ||
2b740303 | 1299 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1300 | { |
82b0f8c3 | 1301 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1302 | struct page *page = NULL, *new_page; |
00501b53 | 1303 | struct mem_cgroup *memcg; |
82b0f8c3 | 1304 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
ac46d4f3 | 1305 | struct mmu_notifier_range range; |
3b363692 | 1306 | gfp_t huge_gfp; /* for allocation and charge */ |
2b740303 | 1307 | vm_fault_t ret = 0; |
71e3aac0 | 1308 | |
82b0f8c3 | 1309 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1310 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1311 | if (is_huge_zero_pmd(orig_pmd)) |
1312 | goto alloc; | |
82b0f8c3 JK |
1313 | spin_lock(vmf->ptl); |
1314 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1315 | goto out_unlock; |
1316 | ||
1317 | page = pmd_page(orig_pmd); | |
309381fe | 1318 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1319 | /* |
1320 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1321 | * part. |
1f25fe20 | 1322 | */ |
ba3c4ce6 HY |
1323 | if (!trylock_page(page)) { |
1324 | get_page(page); | |
1325 | spin_unlock(vmf->ptl); | |
1326 | lock_page(page); | |
1327 | spin_lock(vmf->ptl); | |
1328 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1329 | unlock_page(page); | |
1330 | put_page(page); | |
1331 | goto out_unlock; | |
1332 | } | |
1333 | put_page(page); | |
1334 | } | |
1335 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1336 | pmd_t entry; |
1337 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1338 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1339 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1340 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1341 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1342 | unlock_page(page); |
71e3aac0 AA |
1343 | goto out_unlock; |
1344 | } | |
ba3c4ce6 | 1345 | unlock_page(page); |
ddc58f27 | 1346 | get_page(page); |
82b0f8c3 | 1347 | spin_unlock(vmf->ptl); |
93b4796d | 1348 | alloc: |
7635d9cb | 1349 | if (__transparent_hugepage_enabled(vma) && |
077fcf11 | 1350 | !transparent_hugepage_debug_cow()) { |
92717d42 AA |
1351 | huge_gfp = alloc_hugepage_direct_gfpmask(vma, haddr); |
1352 | new_page = alloc_pages_vma(huge_gfp, HPAGE_PMD_ORDER, vma, | |
1353 | haddr, numa_node_id()); | |
077fcf11 | 1354 | } else |
71e3aac0 AA |
1355 | new_page = NULL; |
1356 | ||
9a982250 KS |
1357 | if (likely(new_page)) { |
1358 | prep_transhuge_page(new_page); | |
1359 | } else { | |
eecc1e42 | 1360 | if (!page) { |
82b0f8c3 | 1361 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1362 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1363 | } else { |
82b0f8c3 | 1364 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1365 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1366 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1367 | ret |= VM_FAULT_FALLBACK; |
1368 | } | |
ddc58f27 | 1369 | put_page(page); |
93b4796d | 1370 | } |
17766dde | 1371 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1372 | goto out; |
1373 | } | |
1374 | ||
2cf85583 | 1375 | if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, |
2a70f6a7 | 1376 | huge_gfp, &memcg, true))) { |
b9bbfbe3 | 1377 | put_page(new_page); |
82b0f8c3 | 1378 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1379 | if (page) |
ddc58f27 | 1380 | put_page(page); |
9845cbbd | 1381 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1382 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1383 | goto out; |
1384 | } | |
1385 | ||
17766dde | 1386 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 1387 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
17766dde | 1388 | |
eecc1e42 | 1389 | if (!page) |
c79b57e4 | 1390 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d | 1391 | else |
c9f4cd71 HY |
1392 | copy_user_huge_page(new_page, page, vmf->address, |
1393 | vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1394 | __SetPageUptodate(new_page); |
1395 | ||
7269f999 JG |
1396 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1397 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1398 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1399 | |
82b0f8c3 | 1400 | spin_lock(vmf->ptl); |
93b4796d | 1401 | if (page) |
ddc58f27 | 1402 | put_page(page); |
82b0f8c3 JK |
1403 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1404 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1405 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1406 | put_page(new_page); |
2ec74c3e | 1407 | goto out_mn; |
b9bbfbe3 | 1408 | } else { |
71e3aac0 | 1409 | pmd_t entry; |
3122359a | 1410 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
f55e1014 | 1411 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 | 1412 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1413 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1414 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1415 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1416 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1417 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1418 | if (!page) { |
bae473a4 | 1419 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1420 | } else { |
309381fe | 1421 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1422 | page_remove_rmap(page, true); |
93b4796d KS |
1423 | put_page(page); |
1424 | } | |
71e3aac0 AA |
1425 | ret |= VM_FAULT_WRITE; |
1426 | } | |
82b0f8c3 | 1427 | spin_unlock(vmf->ptl); |
2ec74c3e | 1428 | out_mn: |
4645b9fe JG |
1429 | /* |
1430 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1431 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1432 | */ | |
ac46d4f3 | 1433 | mmu_notifier_invalidate_range_only_end(&range); |
71e3aac0 AA |
1434 | out: |
1435 | return ret; | |
2ec74c3e | 1436 | out_unlock: |
82b0f8c3 | 1437 | spin_unlock(vmf->ptl); |
2ec74c3e | 1438 | return ret; |
71e3aac0 AA |
1439 | } |
1440 | ||
8310d48b KF |
1441 | /* |
1442 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1443 | * after we've gone through a COW cycle and they are dirty. | |
1444 | */ | |
1445 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1446 | { | |
f6f37321 | 1447 | return pmd_write(pmd) || |
8310d48b KF |
1448 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); |
1449 | } | |
1450 | ||
b676b293 | 1451 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1452 | unsigned long addr, |
1453 | pmd_t *pmd, | |
1454 | unsigned int flags) | |
1455 | { | |
b676b293 | 1456 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1457 | struct page *page = NULL; |
1458 | ||
c4088ebd | 1459 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1460 | |
8310d48b | 1461 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1462 | goto out; |
1463 | ||
85facf25 KS |
1464 | /* Avoid dumping huge zero page */ |
1465 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1466 | return ERR_PTR(-EFAULT); | |
1467 | ||
2b4847e7 | 1468 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1469 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1470 | goto out; |
1471 | ||
71e3aac0 | 1472 | page = pmd_page(*pmd); |
ca120cf6 | 1473 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1474 | if (flags & FOLL_TOUCH) |
a8f97366 | 1475 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1476 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1477 | /* |
1478 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1479 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1480 | * | |
9a73f61b KS |
1481 | * For anon THP: |
1482 | * | |
e90309c9 KS |
1483 | * In most cases the pmd is the only mapping of the page as we |
1484 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1485 | * writable private mappings in populate_vma_page_range(). | |
1486 | * | |
1487 | * The only scenario when we have the page shared here is if we | |
1488 | * mlocking read-only mapping shared over fork(). We skip | |
1489 | * mlocking such pages. | |
9a73f61b KS |
1490 | * |
1491 | * For file THP: | |
1492 | * | |
1493 | * We can expect PageDoubleMap() to be stable under page lock: | |
1494 | * for file pages we set it in page_add_file_rmap(), which | |
1495 | * requires page to be locked. | |
e90309c9 | 1496 | */ |
9a73f61b KS |
1497 | |
1498 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1499 | goto skip_mlock; | |
1500 | if (PageDoubleMap(page) || !page->mapping) | |
1501 | goto skip_mlock; | |
1502 | if (!trylock_page(page)) | |
1503 | goto skip_mlock; | |
1504 | lru_add_drain(); | |
1505 | if (page->mapping && !PageDoubleMap(page)) | |
1506 | mlock_vma_page(page); | |
1507 | unlock_page(page); | |
b676b293 | 1508 | } |
9a73f61b | 1509 | skip_mlock: |
71e3aac0 | 1510 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1511 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1512 | if (flags & FOLL_GET) |
ddc58f27 | 1513 | get_page(page); |
71e3aac0 AA |
1514 | |
1515 | out: | |
1516 | return page; | |
1517 | } | |
1518 | ||
d10e63f2 | 1519 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1520 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1521 | { |
82b0f8c3 | 1522 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1523 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1524 | struct page *page; |
82b0f8c3 | 1525 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1526 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1527 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1528 | bool page_locked; |
1529 | bool migrated = false; | |
b191f9b1 | 1530 | bool was_writable; |
6688cc05 | 1531 | int flags = 0; |
d10e63f2 | 1532 | |
82b0f8c3 JK |
1533 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1534 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1535 | goto out_unlock; |
1536 | ||
de466bd6 MG |
1537 | /* |
1538 | * If there are potential migrations, wait for completion and retry | |
1539 | * without disrupting NUMA hinting information. Do not relock and | |
1540 | * check_same as the page may no longer be mapped. | |
1541 | */ | |
82b0f8c3 JK |
1542 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1543 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1544 | if (!get_page_unless_zero(page)) |
1545 | goto out_unlock; | |
82b0f8c3 | 1546 | spin_unlock(vmf->ptl); |
9a1ea439 | 1547 | put_and_wait_on_page_locked(page); |
de466bd6 MG |
1548 | goto out; |
1549 | } | |
1550 | ||
d10e63f2 | 1551 | page = pmd_page(pmd); |
a1a46184 | 1552 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1553 | page_nid = page_to_nid(page); |
90572890 | 1554 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1555 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1556 | if (page_nid == this_nid) { |
03c5a6e1 | 1557 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1558 | flags |= TNF_FAULT_LOCAL; |
1559 | } | |
4daae3b4 | 1560 | |
bea66fbd | 1561 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1562 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1563 | flags |= TNF_NO_GROUP; |
1564 | ||
ff9042b1 MG |
1565 | /* |
1566 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1567 | * page_table_lock if at all possible | |
1568 | */ | |
b8916634 MG |
1569 | page_locked = trylock_page(page); |
1570 | target_nid = mpol_misplaced(page, vma, haddr); | |
98fa15f3 | 1571 | if (target_nid == NUMA_NO_NODE) { |
b8916634 | 1572 | /* If the page was locked, there are no parallel migrations */ |
a54a407f | 1573 | if (page_locked) |
b8916634 | 1574 | goto clear_pmdnuma; |
2b4847e7 | 1575 | } |
4daae3b4 | 1576 | |
de466bd6 | 1577 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1578 | if (!page_locked) { |
98fa15f3 | 1579 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1580 | if (!get_page_unless_zero(page)) |
1581 | goto out_unlock; | |
82b0f8c3 | 1582 | spin_unlock(vmf->ptl); |
9a1ea439 | 1583 | put_and_wait_on_page_locked(page); |
b8916634 MG |
1584 | goto out; |
1585 | } | |
1586 | ||
2b4847e7 MG |
1587 | /* |
1588 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1589 | * to serialises splits | |
1590 | */ | |
b8916634 | 1591 | get_page(page); |
82b0f8c3 | 1592 | spin_unlock(vmf->ptl); |
b8916634 | 1593 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1594 | |
c69307d5 | 1595 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1596 | spin_lock(vmf->ptl); |
1597 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1598 | unlock_page(page); |
1599 | put_page(page); | |
98fa15f3 | 1600 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1601 | goto out_unlock; |
b32967ff | 1602 | } |
ff9042b1 | 1603 | |
c3a489ca MG |
1604 | /* Bail if we fail to protect against THP splits for any reason */ |
1605 | if (unlikely(!anon_vma)) { | |
1606 | put_page(page); | |
98fa15f3 | 1607 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1608 | goto clear_pmdnuma; |
1609 | } | |
1610 | ||
8b1b436d PZ |
1611 | /* |
1612 | * Since we took the NUMA fault, we must have observed the !accessible | |
1613 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1614 | * modifying the page we're about to migrate. | |
1615 | * | |
1616 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1617 | * inc_tlb_flush_pending(). |
1618 | * | |
1619 | * We are not sure a pending tlb flush here is for a huge page | |
1620 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1621 | */ |
7066f0f9 | 1622 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1623 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1624 | /* |
1625 | * change_huge_pmd() released the pmd lock before | |
1626 | * invalidating the secondary MMUs sharing the primary | |
1627 | * MMU pagetables (with ->invalidate_range()). The | |
1628 | * mmu_notifier_invalidate_range_end() (which | |
1629 | * internally calls ->invalidate_range()) in | |
1630 | * change_pmd_range() will run after us, so we can't | |
1631 | * rely on it here and we need an explicit invalidate. | |
1632 | */ | |
1633 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1634 | haddr + HPAGE_PMD_SIZE); | |
1635 | } | |
8b1b436d | 1636 | |
a54a407f MG |
1637 | /* |
1638 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1639 | * and access rights restored. |
a54a407f | 1640 | */ |
82b0f8c3 | 1641 | spin_unlock(vmf->ptl); |
8b1b436d | 1642 | |
bae473a4 | 1643 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1644 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1645 | if (migrated) { |
1646 | flags |= TNF_MIGRATED; | |
8191acbd | 1647 | page_nid = target_nid; |
074c2381 MG |
1648 | } else |
1649 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1650 | |
8191acbd | 1651 | goto out; |
b32967ff | 1652 | clear_pmdnuma: |
a54a407f | 1653 | BUG_ON(!PageLocked(page)); |
288bc549 | 1654 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1655 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1656 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1657 | if (was_writable) |
1658 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1659 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1660 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1661 | unlock_page(page); |
d10e63f2 | 1662 | out_unlock: |
82b0f8c3 | 1663 | spin_unlock(vmf->ptl); |
b8916634 MG |
1664 | |
1665 | out: | |
1666 | if (anon_vma) | |
1667 | page_unlock_anon_vma_read(anon_vma); | |
1668 | ||
98fa15f3 | 1669 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1670 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1671 | flags); |
8191acbd | 1672 | |
d10e63f2 MG |
1673 | return 0; |
1674 | } | |
1675 | ||
319904ad HY |
1676 | /* |
1677 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1678 | * Otherwise, return false. | |
1679 | */ | |
1680 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1681 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1682 | { |
1683 | spinlock_t *ptl; | |
1684 | pmd_t orig_pmd; | |
1685 | struct page *page; | |
1686 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1687 | bool ret = false; |
b8d3c4c3 | 1688 | |
ed6a7935 | 1689 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1690 | |
b6ec57f4 KS |
1691 | ptl = pmd_trans_huge_lock(pmd, vma); |
1692 | if (!ptl) | |
25eedabe | 1693 | goto out_unlocked; |
b8d3c4c3 MK |
1694 | |
1695 | orig_pmd = *pmd; | |
319904ad | 1696 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1697 | goto out; |
b8d3c4c3 | 1698 | |
84c3fc4e ZY |
1699 | if (unlikely(!pmd_present(orig_pmd))) { |
1700 | VM_BUG_ON(thp_migration_supported() && | |
1701 | !is_pmd_migration_entry(orig_pmd)); | |
1702 | goto out; | |
1703 | } | |
1704 | ||
b8d3c4c3 MK |
1705 | page = pmd_page(orig_pmd); |
1706 | /* | |
1707 | * If other processes are mapping this page, we couldn't discard | |
1708 | * the page unless they all do MADV_FREE so let's skip the page. | |
1709 | */ | |
1710 | if (page_mapcount(page) != 1) | |
1711 | goto out; | |
1712 | ||
1713 | if (!trylock_page(page)) | |
1714 | goto out; | |
1715 | ||
1716 | /* | |
1717 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1718 | * will deactivate only them. | |
1719 | */ | |
1720 | if (next - addr != HPAGE_PMD_SIZE) { | |
1721 | get_page(page); | |
1722 | spin_unlock(ptl); | |
9818b8cd | 1723 | split_huge_page(page); |
b8d3c4c3 | 1724 | unlock_page(page); |
bbf29ffc | 1725 | put_page(page); |
b8d3c4c3 MK |
1726 | goto out_unlocked; |
1727 | } | |
1728 | ||
1729 | if (PageDirty(page)) | |
1730 | ClearPageDirty(page); | |
1731 | unlock_page(page); | |
1732 | ||
b8d3c4c3 | 1733 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1734 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1735 | orig_pmd = pmd_mkold(orig_pmd); |
1736 | orig_pmd = pmd_mkclean(orig_pmd); | |
1737 | ||
1738 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1739 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1740 | } | |
802a3a92 SL |
1741 | |
1742 | mark_page_lazyfree(page); | |
319904ad | 1743 | ret = true; |
b8d3c4c3 MK |
1744 | out: |
1745 | spin_unlock(ptl); | |
1746 | out_unlocked: | |
1747 | return ret; | |
1748 | } | |
1749 | ||
953c66c2 AK |
1750 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1751 | { | |
1752 | pgtable_t pgtable; | |
1753 | ||
1754 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1755 | pte_free(mm, pgtable); | |
c4812909 | 1756 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1757 | } |
1758 | ||
71e3aac0 | 1759 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1760 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1761 | { |
da146769 | 1762 | pmd_t orig_pmd; |
bf929152 | 1763 | spinlock_t *ptl; |
71e3aac0 | 1764 | |
ed6a7935 | 1765 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1766 | |
b6ec57f4 KS |
1767 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1768 | if (!ptl) | |
da146769 KS |
1769 | return 0; |
1770 | /* | |
1771 | * For architectures like ppc64 we look at deposited pgtable | |
1772 | * when calling pmdp_huge_get_and_clear. So do the | |
1773 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1774 | * operations. | |
1775 | */ | |
1776 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1777 | tlb->fullmm); | |
1778 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1779 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1780 | if (arch_needs_pgtable_deposit()) |
1781 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1782 | spin_unlock(ptl); |
1783 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1784 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1785 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1786 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1787 | spin_unlock(ptl); |
c0f2e176 | 1788 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1789 | } else { |
616b8371 ZY |
1790 | struct page *page = NULL; |
1791 | int flush_needed = 1; | |
1792 | ||
1793 | if (pmd_present(orig_pmd)) { | |
1794 | page = pmd_page(orig_pmd); | |
1795 | page_remove_rmap(page, true); | |
1796 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1797 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1798 | } else if (thp_migration_supported()) { | |
1799 | swp_entry_t entry; | |
1800 | ||
1801 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1802 | entry = pmd_to_swp_entry(orig_pmd); | |
1803 | page = pfn_to_page(swp_offset(entry)); | |
1804 | flush_needed = 0; | |
1805 | } else | |
1806 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1807 | ||
b5072380 | 1808 | if (PageAnon(page)) { |
c14a6eb4 | 1809 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1810 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1811 | } else { | |
953c66c2 AK |
1812 | if (arch_needs_pgtable_deposit()) |
1813 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1814 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1815 | } |
616b8371 | 1816 | |
da146769 | 1817 | spin_unlock(ptl); |
616b8371 ZY |
1818 | if (flush_needed) |
1819 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1820 | } |
da146769 | 1821 | return 1; |
71e3aac0 AA |
1822 | } |
1823 | ||
1dd38b6c AK |
1824 | #ifndef pmd_move_must_withdraw |
1825 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1826 | spinlock_t *old_pmd_ptl, | |
1827 | struct vm_area_struct *vma) | |
1828 | { | |
1829 | /* | |
1830 | * With split pmd lock we also need to move preallocated | |
1831 | * PTE page table if new_pmd is on different PMD page table. | |
1832 | * | |
1833 | * We also don't deposit and withdraw tables for file pages. | |
1834 | */ | |
1835 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1836 | } | |
1837 | #endif | |
1838 | ||
ab6e3d09 NH |
1839 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1840 | { | |
1841 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1842 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1843 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1844 | else if (pmd_present(pmd)) | |
1845 | pmd = pmd_mksoft_dirty(pmd); | |
1846 | #endif | |
1847 | return pmd; | |
1848 | } | |
1849 | ||
bf8616d5 | 1850 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1851 | unsigned long new_addr, unsigned long old_end, |
eb66ae03 | 1852 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1853 | { |
bf929152 | 1854 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1855 | pmd_t pmd; |
37a1c49a | 1856 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1857 | bool force_flush = false; |
37a1c49a AA |
1858 | |
1859 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1860 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1861 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1862 | return false; |
37a1c49a AA |
1863 | |
1864 | /* | |
1865 | * The destination pmd shouldn't be established, free_pgtables() | |
1866 | * should have release it. | |
1867 | */ | |
1868 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1869 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1870 | return false; |
37a1c49a AA |
1871 | } |
1872 | ||
bf929152 KS |
1873 | /* |
1874 | * We don't have to worry about the ordering of src and dst | |
1875 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1876 | */ | |
b6ec57f4 KS |
1877 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1878 | if (old_ptl) { | |
bf929152 KS |
1879 | new_ptl = pmd_lockptr(mm, new_pmd); |
1880 | if (new_ptl != old_ptl) | |
1881 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1882 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1883 | if (pmd_present(pmd)) |
a2ce2666 | 1884 | force_flush = true; |
025c5b24 | 1885 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1886 | |
1dd38b6c | 1887 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1888 | pgtable_t pgtable; |
3592806c KS |
1889 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1890 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1891 | } |
ab6e3d09 NH |
1892 | pmd = move_soft_dirty_pmd(pmd); |
1893 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1894 | if (force_flush) |
1895 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1896 | if (new_ptl != old_ptl) |
1897 | spin_unlock(new_ptl); | |
bf929152 | 1898 | spin_unlock(old_ptl); |
4b471e88 | 1899 | return true; |
37a1c49a | 1900 | } |
4b471e88 | 1901 | return false; |
37a1c49a AA |
1902 | } |
1903 | ||
f123d74a MG |
1904 | /* |
1905 | * Returns | |
1906 | * - 0 if PMD could not be locked | |
1907 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1908 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1909 | */ | |
cd7548ab | 1910 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1911 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1912 | { |
1913 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1914 | spinlock_t *ptl; |
0a85e51d KS |
1915 | pmd_t entry; |
1916 | bool preserve_write; | |
1917 | int ret; | |
cd7548ab | 1918 | |
b6ec57f4 | 1919 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1920 | if (!ptl) |
1921 | return 0; | |
e944fd67 | 1922 | |
0a85e51d KS |
1923 | preserve_write = prot_numa && pmd_write(*pmd); |
1924 | ret = 1; | |
e944fd67 | 1925 | |
84c3fc4e ZY |
1926 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1927 | if (is_swap_pmd(*pmd)) { | |
1928 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1929 | ||
1930 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1931 | if (is_write_migration_entry(entry)) { | |
1932 | pmd_t newpmd; | |
1933 | /* | |
1934 | * A protection check is difficult so | |
1935 | * just be safe and disable write | |
1936 | */ | |
1937 | make_migration_entry_read(&entry); | |
1938 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1939 | if (pmd_swp_soft_dirty(*pmd)) |
1940 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1941 | set_pmd_at(mm, addr, pmd, newpmd); |
1942 | } | |
1943 | goto unlock; | |
1944 | } | |
1945 | #endif | |
1946 | ||
0a85e51d KS |
1947 | /* |
1948 | * Avoid trapping faults against the zero page. The read-only | |
1949 | * data is likely to be read-cached on the local CPU and | |
1950 | * local/remote hits to the zero page are not interesting. | |
1951 | */ | |
1952 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1953 | goto unlock; | |
025c5b24 | 1954 | |
0a85e51d KS |
1955 | if (prot_numa && pmd_protnone(*pmd)) |
1956 | goto unlock; | |
1957 | ||
ced10803 KS |
1958 | /* |
1959 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1960 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1961 | * which is also under down_read(mmap_sem): | |
1962 | * | |
1963 | * CPU0: CPU1: | |
1964 | * change_huge_pmd(prot_numa=1) | |
1965 | * pmdp_huge_get_and_clear_notify() | |
1966 | * madvise_dontneed() | |
1967 | * zap_pmd_range() | |
1968 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1969 | * // skip the pmd | |
1970 | * set_pmd_at(); | |
1971 | * // pmd is re-established | |
1972 | * | |
1973 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1974 | * which may break userspace. | |
1975 | * | |
1976 | * pmdp_invalidate() is required to make sure we don't miss | |
1977 | * dirty/young flags set by hardware. | |
1978 | */ | |
a3cf988f | 1979 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1980 | |
0a85e51d KS |
1981 | entry = pmd_modify(entry, newprot); |
1982 | if (preserve_write) | |
1983 | entry = pmd_mk_savedwrite(entry); | |
1984 | ret = HPAGE_PMD_NR; | |
1985 | set_pmd_at(mm, addr, pmd, entry); | |
1986 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1987 | unlock: | |
1988 | spin_unlock(ptl); | |
025c5b24 NH |
1989 | return ret; |
1990 | } | |
1991 | ||
1992 | /* | |
8f19b0c0 | 1993 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1994 | * |
8f19b0c0 HY |
1995 | * Note that if it returns page table lock pointer, this routine returns without |
1996 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1997 | */ |
b6ec57f4 | 1998 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1999 | { |
b6ec57f4 KS |
2000 | spinlock_t *ptl; |
2001 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
2002 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
2003 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
2004 | return ptl; |
2005 | spin_unlock(ptl); | |
2006 | return NULL; | |
cd7548ab JW |
2007 | } |
2008 | ||
a00cc7d9 MW |
2009 | /* |
2010 | * Returns true if a given pud maps a thp, false otherwise. | |
2011 | * | |
2012 | * Note that if it returns true, this routine returns without unlocking page | |
2013 | * table lock. So callers must unlock it. | |
2014 | */ | |
2015 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
2016 | { | |
2017 | spinlock_t *ptl; | |
2018 | ||
2019 | ptl = pud_lock(vma->vm_mm, pud); | |
2020 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
2021 | return ptl; | |
2022 | spin_unlock(ptl); | |
2023 | return NULL; | |
2024 | } | |
2025 | ||
2026 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
2027 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
2028 | pud_t *pud, unsigned long addr) | |
2029 | { | |
a00cc7d9 MW |
2030 | spinlock_t *ptl; |
2031 | ||
2032 | ptl = __pud_trans_huge_lock(pud, vma); | |
2033 | if (!ptl) | |
2034 | return 0; | |
2035 | /* | |
2036 | * For architectures like ppc64 we look at deposited pgtable | |
2037 | * when calling pudp_huge_get_and_clear. So do the | |
2038 | * pgtable_trans_huge_withdraw after finishing pudp related | |
2039 | * operations. | |
2040 | */ | |
70516b93 | 2041 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 MW |
2042 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2043 | if (vma_is_dax(vma)) { | |
2044 | spin_unlock(ptl); | |
2045 | /* No zero page support yet */ | |
2046 | } else { | |
2047 | /* No support for anonymous PUD pages yet */ | |
2048 | BUG(); | |
2049 | } | |
2050 | return 1; | |
2051 | } | |
2052 | ||
2053 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2054 | unsigned long haddr) | |
2055 | { | |
2056 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2057 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2058 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2059 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2060 | ||
ce9311cf | 2061 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2062 | |
2063 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2064 | } | |
2065 | ||
2066 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2067 | unsigned long address) | |
2068 | { | |
2069 | spinlock_t *ptl; | |
ac46d4f3 | 2070 | struct mmu_notifier_range range; |
a00cc7d9 | 2071 | |
7269f999 | 2072 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2073 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2074 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2075 | mmu_notifier_invalidate_range_start(&range); | |
2076 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2077 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2078 | goto out; | |
ac46d4f3 | 2079 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2080 | |
2081 | out: | |
2082 | spin_unlock(ptl); | |
4645b9fe JG |
2083 | /* |
2084 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2085 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2086 | */ | |
ac46d4f3 | 2087 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2088 | } |
2089 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2090 | ||
eef1b3ba KS |
2091 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2092 | unsigned long haddr, pmd_t *pmd) | |
2093 | { | |
2094 | struct mm_struct *mm = vma->vm_mm; | |
2095 | pgtable_t pgtable; | |
2096 | pmd_t _pmd; | |
2097 | int i; | |
2098 | ||
0f10851e JG |
2099 | /* |
2100 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2101 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2102 | * replacing a zero pmd write protected page with a zero pte write | |
2103 | * protected page. | |
2104 | * | |
ad56b738 | 2105 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2106 | */ |
2107 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2108 | |
2109 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2110 | pmd_populate(mm, &_pmd, pgtable); | |
2111 | ||
2112 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2113 | pte_t *pte, entry; | |
2114 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2115 | entry = pte_mkspecial(entry); | |
2116 | pte = pte_offset_map(&_pmd, haddr); | |
2117 | VM_BUG_ON(!pte_none(*pte)); | |
2118 | set_pte_at(mm, haddr, pte, entry); | |
2119 | pte_unmap(pte); | |
2120 | } | |
2121 | smp_wmb(); /* make pte visible before pmd */ | |
2122 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2123 | } |
2124 | ||
2125 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2126 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2127 | { |
2128 | struct mm_struct *mm = vma->vm_mm; | |
2129 | struct page *page; | |
2130 | pgtable_t pgtable; | |
423ac9af | 2131 | pmd_t old_pmd, _pmd; |
a3cf988f | 2132 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2133 | unsigned long addr; |
eef1b3ba KS |
2134 | int i; |
2135 | ||
2136 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2137 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2138 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2139 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2140 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2141 | |
2142 | count_vm_event(THP_SPLIT_PMD); | |
2143 | ||
d21b9e57 KS |
2144 | if (!vma_is_anonymous(vma)) { |
2145 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2146 | /* |
2147 | * We are going to unmap this huge page. So | |
2148 | * just go ahead and zap it | |
2149 | */ | |
2150 | if (arch_needs_pgtable_deposit()) | |
2151 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2152 | if (vma_is_dax(vma)) |
2153 | return; | |
2154 | page = pmd_page(_pmd); | |
e1f1b157 HD |
2155 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2156 | set_page_dirty(page); | |
d21b9e57 KS |
2157 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2158 | SetPageReferenced(page); | |
2159 | page_remove_rmap(page, true); | |
2160 | put_page(page); | |
fadae295 | 2161 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba KS |
2162 | return; |
2163 | } else if (is_huge_zero_pmd(*pmd)) { | |
4645b9fe JG |
2164 | /* |
2165 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2166 | * mmu_notifier_invalidate_range() see comments below inside | |
2167 | * __split_huge_pmd() ? | |
2168 | * | |
2169 | * We are going from a zero huge page write protected to zero | |
2170 | * small page also write protected so it does not seems useful | |
2171 | * to invalidate secondary mmu at this time. | |
2172 | */ | |
eef1b3ba KS |
2173 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2174 | } | |
2175 | ||
423ac9af AK |
2176 | /* |
2177 | * Up to this point the pmd is present and huge and userland has the | |
2178 | * whole access to the hugepage during the split (which happens in | |
2179 | * place). If we overwrite the pmd with the not-huge version pointing | |
2180 | * to the pte here (which of course we could if all CPUs were bug | |
2181 | * free), userland could trigger a small page size TLB miss on the | |
2182 | * small sized TLB while the hugepage TLB entry is still established in | |
2183 | * the huge TLB. Some CPU doesn't like that. | |
2184 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2185 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2186 | * only safe if the permission and cache attributes of the two entries | |
2187 | * loaded in the two TLB is identical (which should be the case here). | |
2188 | * But it is generally safer to never allow small and huge TLB entries | |
2189 | * for the same virtual address to be loaded simultaneously. So instead | |
2190 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2191 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2192 | * must remain set at all times on the pmd until the split is complete | |
2193 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2194 | * non-huge version of the pmd entry with pmd_populate. | |
2195 | */ | |
2196 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2197 | ||
423ac9af | 2198 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2199 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2200 | swp_entry_t entry; |
2201 | ||
423ac9af | 2202 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e | 2203 | page = pfn_to_page(swp_offset(entry)); |
2e83ee1d PX |
2204 | write = is_write_migration_entry(entry); |
2205 | young = false; | |
2206 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
2207 | } else { | |
423ac9af | 2208 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2209 | if (pmd_dirty(old_pmd)) |
2210 | SetPageDirty(page); | |
2211 | write = pmd_write(old_pmd); | |
2212 | young = pmd_young(old_pmd); | |
2213 | soft_dirty = pmd_soft_dirty(old_pmd); | |
2214 | } | |
eef1b3ba | 2215 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2216 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2217 | |
423ac9af AK |
2218 | /* |
2219 | * Withdraw the table only after we mark the pmd entry invalid. | |
2220 | * This's critical for some architectures (Power). | |
2221 | */ | |
eef1b3ba KS |
2222 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2223 | pmd_populate(mm, &_pmd, pgtable); | |
2224 | ||
2ac015e2 | 2225 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2226 | pte_t entry, *pte; |
2227 | /* | |
2228 | * Note that NUMA hinting access restrictions are not | |
2229 | * transferred to avoid any possibility of altering | |
2230 | * permissions across VMAs. | |
2231 | */ | |
84c3fc4e | 2232 | if (freeze || pmd_migration) { |
ba988280 KS |
2233 | swp_entry_t swp_entry; |
2234 | swp_entry = make_migration_entry(page + i, write); | |
2235 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2236 | if (soft_dirty) |
2237 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2238 | } else { |
6d2329f8 | 2239 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2240 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2241 | if (!write) |
2242 | entry = pte_wrprotect(entry); | |
2243 | if (!young) | |
2244 | entry = pte_mkold(entry); | |
804dd150 AA |
2245 | if (soft_dirty) |
2246 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2247 | } |
2ac015e2 | 2248 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2249 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2250 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2251 | atomic_inc(&page[i]._mapcount); |
2252 | pte_unmap(pte); | |
2253 | } | |
2254 | ||
2255 | /* | |
2256 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2257 | * false-negative page_mapped(). | |
2258 | */ | |
2259 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2260 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2261 | atomic_inc(&page[i]._mapcount); | |
2262 | } | |
2263 | ||
2264 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2265 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2266 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2267 | if (TestClearPageDoubleMap(page)) { |
2268 | /* No need in mapcount reference anymore */ | |
2269 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2270 | atomic_dec(&page[i]._mapcount); | |
2271 | } | |
2272 | } | |
2273 | ||
2274 | smp_wmb(); /* make pte visible before pmd */ | |
2275 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2276 | |
2277 | if (freeze) { | |
2ac015e2 | 2278 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2279 | page_remove_rmap(page + i, false); |
2280 | put_page(page + i); | |
2281 | } | |
2282 | } | |
eef1b3ba KS |
2283 | } |
2284 | ||
2285 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2286 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2287 | { |
2288 | spinlock_t *ptl; | |
ac46d4f3 | 2289 | struct mmu_notifier_range range; |
eef1b3ba | 2290 | |
7269f999 | 2291 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2292 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2293 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2294 | mmu_notifier_invalidate_range_start(&range); | |
2295 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2296 | |
2297 | /* | |
2298 | * If caller asks to setup a migration entries, we need a page to check | |
2299 | * pmd against. Otherwise we can end up replacing wrong page. | |
2300 | */ | |
2301 | VM_BUG_ON(freeze && !page); | |
2302 | if (page && page != pmd_page(*pmd)) | |
2303 | goto out; | |
2304 | ||
5c7fb56e | 2305 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2306 | page = pmd_page(*pmd); |
5c7fb56e | 2307 | if (PageMlocked(page)) |
5f737714 | 2308 | clear_page_mlock(page); |
84c3fc4e | 2309 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2310 | goto out; |
ac46d4f3 | 2311 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2312 | out: |
eef1b3ba | 2313 | spin_unlock(ptl); |
4645b9fe JG |
2314 | /* |
2315 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2316 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2317 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2318 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2319 | * fault will trigger a flush_notify before pointing to a new page | |
2320 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2321 | * page in the meantime) | |
2322 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2323 | * to invalidate secondary tlb entry they are all still valid. | |
2324 | * any further changes to individual pte will notify. So no need | |
2325 | * to call mmu_notifier->invalidate_range() | |
2326 | */ | |
ac46d4f3 | 2327 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2328 | } |
2329 | ||
fec89c10 KS |
2330 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2331 | bool freeze, struct page *page) | |
94fcc585 | 2332 | { |
f72e7dcd | 2333 | pgd_t *pgd; |
c2febafc | 2334 | p4d_t *p4d; |
f72e7dcd | 2335 | pud_t *pud; |
94fcc585 AA |
2336 | pmd_t *pmd; |
2337 | ||
78ddc534 | 2338 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2339 | if (!pgd_present(*pgd)) |
2340 | return; | |
2341 | ||
c2febafc KS |
2342 | p4d = p4d_offset(pgd, address); |
2343 | if (!p4d_present(*p4d)) | |
2344 | return; | |
2345 | ||
2346 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2347 | if (!pud_present(*pud)) |
2348 | return; | |
2349 | ||
2350 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2351 | |
33f4751e | 2352 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2353 | } |
2354 | ||
e1b9996b | 2355 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2356 | unsigned long start, |
2357 | unsigned long end, | |
2358 | long adjust_next) | |
2359 | { | |
2360 | /* | |
2361 | * If the new start address isn't hpage aligned and it could | |
2362 | * previously contain an hugepage: check if we need to split | |
2363 | * an huge pmd. | |
2364 | */ | |
2365 | if (start & ~HPAGE_PMD_MASK && | |
2366 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2367 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2368 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2369 | |
2370 | /* | |
2371 | * If the new end address isn't hpage aligned and it could | |
2372 | * previously contain an hugepage: check if we need to split | |
2373 | * an huge pmd. | |
2374 | */ | |
2375 | if (end & ~HPAGE_PMD_MASK && | |
2376 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2377 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2378 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2379 | |
2380 | /* | |
2381 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2382 | * vm_next->vm_start isn't page aligned and it could previously | |
2383 | * contain an hugepage: check if we need to split an huge pmd. | |
2384 | */ | |
2385 | if (adjust_next > 0) { | |
2386 | struct vm_area_struct *next = vma->vm_next; | |
2387 | unsigned long nstart = next->vm_start; | |
2388 | nstart += adjust_next << PAGE_SHIFT; | |
2389 | if (nstart & ~HPAGE_PMD_MASK && | |
2390 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2391 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2392 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2393 | } |
2394 | } | |
e9b61f19 | 2395 | |
906f9cdf | 2396 | static void unmap_page(struct page *page) |
e9b61f19 | 2397 | { |
baa355fd | 2398 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2399 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2400 | bool unmap_success; |
e9b61f19 KS |
2401 | |
2402 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2403 | ||
baa355fd | 2404 | if (PageAnon(page)) |
b5ff8161 | 2405 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2406 | |
666e5a40 MK |
2407 | unmap_success = try_to_unmap(page, ttu_flags); |
2408 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2409 | } |
2410 | ||
906f9cdf | 2411 | static void remap_page(struct page *page) |
e9b61f19 | 2412 | { |
fec89c10 | 2413 | int i; |
ace71a19 KS |
2414 | if (PageTransHuge(page)) { |
2415 | remove_migration_ptes(page, page, true); | |
2416 | } else { | |
2417 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2418 | remove_migration_ptes(page + i, page + i, true); | |
2419 | } | |
e9b61f19 KS |
2420 | } |
2421 | ||
8df651c7 | 2422 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2423 | struct lruvec *lruvec, struct list_head *list) |
2424 | { | |
e9b61f19 KS |
2425 | struct page *page_tail = head + tail; |
2426 | ||
8df651c7 | 2427 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2428 | |
2429 | /* | |
605ca5ed KK |
2430 | * Clone page flags before unfreezing refcount. |
2431 | * | |
2432 | * After successful get_page_unless_zero() might follow flags change, | |
2433 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2434 | */ |
e9b61f19 KS |
2435 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2436 | page_tail->flags |= (head->flags & | |
2437 | ((1L << PG_referenced) | | |
2438 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2439 | (1L << PG_swapcache) | |
e9b61f19 KS |
2440 | (1L << PG_mlocked) | |
2441 | (1L << PG_uptodate) | | |
2442 | (1L << PG_active) | | |
1899ad18 | 2443 | (1L << PG_workingset) | |
e9b61f19 | 2444 | (1L << PG_locked) | |
b8d3c4c3 MK |
2445 | (1L << PG_unevictable) | |
2446 | (1L << PG_dirty))); | |
e9b61f19 | 2447 | |
173d9d9f HD |
2448 | /* ->mapping in first tail page is compound_mapcount */ |
2449 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2450 | page_tail); | |
2451 | page_tail->mapping = head->mapping; | |
2452 | page_tail->index = head->index + tail; | |
2453 | ||
605ca5ed | 2454 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2455 | smp_wmb(); |
2456 | ||
605ca5ed KK |
2457 | /* |
2458 | * Clear PageTail before unfreezing page refcount. | |
2459 | * | |
2460 | * After successful get_page_unless_zero() might follow put_page() | |
2461 | * which needs correct compound_head(). | |
2462 | */ | |
e9b61f19 KS |
2463 | clear_compound_head(page_tail); |
2464 | ||
605ca5ed KK |
2465 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2466 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2467 | PageSwapCache(head))); | |
2468 | ||
e9b61f19 KS |
2469 | if (page_is_young(head)) |
2470 | set_page_young(page_tail); | |
2471 | if (page_is_idle(head)) | |
2472 | set_page_idle(page_tail); | |
2473 | ||
e9b61f19 | 2474 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2475 | |
2476 | /* | |
2477 | * always add to the tail because some iterators expect new | |
2478 | * pages to show after the currently processed elements - e.g. | |
2479 | * migrate_pages | |
2480 | */ | |
e9b61f19 | 2481 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2482 | } |
2483 | ||
baa355fd | 2484 | static void __split_huge_page(struct page *page, struct list_head *list, |
006d3ff2 | 2485 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2486 | { |
2487 | struct page *head = compound_head(page); | |
f4b7e272 | 2488 | pg_data_t *pgdat = page_pgdat(head); |
e9b61f19 | 2489 | struct lruvec *lruvec; |
8df651c7 | 2490 | int i; |
e9b61f19 | 2491 | |
f4b7e272 | 2492 | lruvec = mem_cgroup_page_lruvec(head, pgdat); |
e9b61f19 KS |
2493 | |
2494 | /* complete memcg works before add pages to LRU */ | |
2495 | mem_cgroup_split_huge_fixup(head); | |
2496 | ||
baa355fd | 2497 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2498 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2499 | /* Some pages can be beyond i_size: drop them from page cache */ |
2500 | if (head[i].index >= end) { | |
2d077d4b | 2501 | ClearPageDirty(head + i); |
baa355fd | 2502 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2503 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2504 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2505 | put_page(head + i); |
2506 | } | |
2507 | } | |
e9b61f19 KS |
2508 | |
2509 | ClearPageCompound(head); | |
f7da677b VB |
2510 | |
2511 | split_page_owner(head, HPAGE_PMD_ORDER); | |
2512 | ||
baa355fd KS |
2513 | /* See comment in __split_huge_page_tail() */ |
2514 | if (PageAnon(head)) { | |
aa5dc07f | 2515 | /* Additional pin to swap cache */ |
38d8b4e6 HY |
2516 | if (PageSwapCache(head)) |
2517 | page_ref_add(head, 2); | |
2518 | else | |
2519 | page_ref_inc(head); | |
baa355fd | 2520 | } else { |
aa5dc07f | 2521 | /* Additional pin to page cache */ |
baa355fd | 2522 | page_ref_add(head, 2); |
b93b0163 | 2523 | xa_unlock(&head->mapping->i_pages); |
baa355fd KS |
2524 | } |
2525 | ||
f4b7e272 | 2526 | spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
e9b61f19 | 2527 | |
906f9cdf | 2528 | remap_page(head); |
e9b61f19 KS |
2529 | |
2530 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2531 | struct page *subpage = head + i; | |
2532 | if (subpage == page) | |
2533 | continue; | |
2534 | unlock_page(subpage); | |
2535 | ||
2536 | /* | |
2537 | * Subpages may be freed if there wasn't any mapping | |
2538 | * like if add_to_swap() is running on a lru page that | |
2539 | * had its mapping zapped. And freeing these pages | |
2540 | * requires taking the lru_lock so we do the put_page | |
2541 | * of the tail pages after the split is complete. | |
2542 | */ | |
2543 | put_page(subpage); | |
2544 | } | |
2545 | } | |
2546 | ||
b20ce5e0 KS |
2547 | int total_mapcount(struct page *page) |
2548 | { | |
dd78fedd | 2549 | int i, compound, ret; |
b20ce5e0 KS |
2550 | |
2551 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2552 | ||
2553 | if (likely(!PageCompound(page))) | |
2554 | return atomic_read(&page->_mapcount) + 1; | |
2555 | ||
dd78fedd | 2556 | compound = compound_mapcount(page); |
b20ce5e0 | 2557 | if (PageHuge(page)) |
dd78fedd KS |
2558 | return compound; |
2559 | ret = compound; | |
b20ce5e0 KS |
2560 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2561 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2562 | /* File pages has compound_mapcount included in _mapcount */ |
2563 | if (!PageAnon(page)) | |
2564 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2565 | if (PageDoubleMap(page)) |
2566 | ret -= HPAGE_PMD_NR; | |
2567 | return ret; | |
2568 | } | |
2569 | ||
6d0a07ed AA |
2570 | /* |
2571 | * This calculates accurately how many mappings a transparent hugepage | |
2572 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2573 | * accuracy is primarily needed to know if copy-on-write faults can | |
2574 | * reuse the page and change the mapping to read-write instead of | |
2575 | * copying them. At the same time this returns the total_mapcount too. | |
2576 | * | |
2577 | * The function returns the highest mapcount any one of the subpages | |
2578 | * has. If the return value is one, even if different processes are | |
2579 | * mapping different subpages of the transparent hugepage, they can | |
2580 | * all reuse it, because each process is reusing a different subpage. | |
2581 | * | |
2582 | * The total_mapcount is instead counting all virtual mappings of the | |
2583 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2584 | * caller all mappings belong to the same "mm" and in turn the | |
2585 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2586 | * local one as no other process may be mapping any of the subpages. | |
2587 | * | |
2588 | * It would be more accurate to replace page_mapcount() with | |
2589 | * page_trans_huge_mapcount(), however we only use | |
2590 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2591 | * need full accuracy to avoid breaking page pinning, because | |
2592 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2593 | */ | |
2594 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2595 | { | |
2596 | int i, ret, _total_mapcount, mapcount; | |
2597 | ||
2598 | /* hugetlbfs shouldn't call it */ | |
2599 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2600 | ||
2601 | if (likely(!PageTransCompound(page))) { | |
2602 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2603 | if (total_mapcount) | |
2604 | *total_mapcount = mapcount; | |
2605 | return mapcount; | |
2606 | } | |
2607 | ||
2608 | page = compound_head(page); | |
2609 | ||
2610 | _total_mapcount = ret = 0; | |
2611 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2612 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2613 | ret = max(ret, mapcount); | |
2614 | _total_mapcount += mapcount; | |
2615 | } | |
2616 | if (PageDoubleMap(page)) { | |
2617 | ret -= 1; | |
2618 | _total_mapcount -= HPAGE_PMD_NR; | |
2619 | } | |
2620 | mapcount = compound_mapcount(page); | |
2621 | ret += mapcount; | |
2622 | _total_mapcount += mapcount; | |
2623 | if (total_mapcount) | |
2624 | *total_mapcount = _total_mapcount; | |
2625 | return ret; | |
2626 | } | |
2627 | ||
b8f593cd HY |
2628 | /* Racy check whether the huge page can be split */ |
2629 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2630 | { | |
2631 | int extra_pins; | |
2632 | ||
aa5dc07f | 2633 | /* Additional pins from page cache */ |
b8f593cd HY |
2634 | if (PageAnon(page)) |
2635 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2636 | else | |
2637 | extra_pins = HPAGE_PMD_NR; | |
2638 | if (pextra_pins) | |
2639 | *pextra_pins = extra_pins; | |
2640 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2641 | } | |
2642 | ||
e9b61f19 KS |
2643 | /* |
2644 | * This function splits huge page into normal pages. @page can point to any | |
2645 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2646 | * | |
2647 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2648 | * The huge page must be locked. | |
2649 | * | |
2650 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2651 | * | |
2652 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2653 | * the hugepage. | |
2654 | * | |
2655 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2656 | * they are not mapped. | |
2657 | * | |
2658 | * Returns 0 if the hugepage is split successfully. | |
2659 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2660 | * us. | |
2661 | */ | |
2662 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2663 | { | |
2664 | struct page *head = compound_head(page); | |
a3d0a918 | 2665 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2666 | struct anon_vma *anon_vma = NULL; |
2667 | struct address_space *mapping = NULL; | |
2668 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2669 | bool mlocked; |
0b9b6fff | 2670 | unsigned long flags; |
006d3ff2 | 2671 | pgoff_t end; |
e9b61f19 KS |
2672 | |
2673 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2674 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2675 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2676 | ||
59807685 HY |
2677 | if (PageWriteback(page)) |
2678 | return -EBUSY; | |
2679 | ||
baa355fd KS |
2680 | if (PageAnon(head)) { |
2681 | /* | |
2682 | * The caller does not necessarily hold an mmap_sem that would | |
2683 | * prevent the anon_vma disappearing so we first we take a | |
2684 | * reference to it and then lock the anon_vma for write. This | |
2685 | * is similar to page_lock_anon_vma_read except the write lock | |
2686 | * is taken to serialise against parallel split or collapse | |
2687 | * operations. | |
2688 | */ | |
2689 | anon_vma = page_get_anon_vma(head); | |
2690 | if (!anon_vma) { | |
2691 | ret = -EBUSY; | |
2692 | goto out; | |
2693 | } | |
006d3ff2 | 2694 | end = -1; |
baa355fd KS |
2695 | mapping = NULL; |
2696 | anon_vma_lock_write(anon_vma); | |
2697 | } else { | |
2698 | mapping = head->mapping; | |
2699 | ||
2700 | /* Truncated ? */ | |
2701 | if (!mapping) { | |
2702 | ret = -EBUSY; | |
2703 | goto out; | |
2704 | } | |
2705 | ||
baa355fd KS |
2706 | anon_vma = NULL; |
2707 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2708 | |
2709 | /* | |
2710 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2711 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2712 | * which cannot be nested inside the page tree lock. So note | |
2713 | * end now: i_size itself may be changed at any moment, but | |
2714 | * head page lock is good enough to serialize the trimming. | |
2715 | */ | |
2716 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2717 | } |
e9b61f19 KS |
2718 | |
2719 | /* | |
906f9cdf | 2720 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2721 | * split PMDs |
2722 | */ | |
b8f593cd | 2723 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2724 | ret = -EBUSY; |
2725 | goto out_unlock; | |
2726 | } | |
2727 | ||
d9654322 | 2728 | mlocked = PageMlocked(page); |
906f9cdf | 2729 | unmap_page(head); |
e9b61f19 KS |
2730 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2731 | ||
d9654322 KS |
2732 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2733 | if (mlocked) | |
2734 | lru_add_drain(); | |
2735 | ||
baa355fd | 2736 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
f4b7e272 | 2737 | spin_lock_irqsave(&pgdata->lru_lock, flags); |
baa355fd KS |
2738 | |
2739 | if (mapping) { | |
aa5dc07f | 2740 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2741 | |
baa355fd | 2742 | /* |
aa5dc07f | 2743 | * Check if the head page is present in page cache. |
baa355fd KS |
2744 | * We assume all tail are present too, if head is there. |
2745 | */ | |
aa5dc07f MW |
2746 | xa_lock(&mapping->i_pages); |
2747 | if (xas_load(&xas) != head) | |
baa355fd KS |
2748 | goto fail; |
2749 | } | |
2750 | ||
0139aa7b | 2751 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2752 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2753 | count = page_count(head); |
2754 | mapcount = total_mapcount(head); | |
baa355fd | 2755 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2756 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2757 | pgdata->split_queue_len--; |
9a982250 KS |
2758 | list_del(page_deferred_list(head)); |
2759 | } | |
65c45377 | 2760 | if (mapping) |
11fb9989 | 2761 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd | 2762 | spin_unlock(&pgdata->split_queue_lock); |
006d3ff2 | 2763 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2764 | if (PageSwapCache(head)) { |
2765 | swp_entry_t entry = { .val = page_private(head) }; | |
2766 | ||
2767 | ret = split_swap_cluster(entry); | |
2768 | } else | |
2769 | ret = 0; | |
e9b61f19 | 2770 | } else { |
baa355fd KS |
2771 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2772 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2773 | mapcount, count); | |
2774 | if (PageTail(page)) | |
2775 | dump_page(head, NULL); | |
2776 | dump_page(page, "total_mapcount(head) > 0"); | |
2777 | BUG(); | |
2778 | } | |
2779 | spin_unlock(&pgdata->split_queue_lock); | |
2780 | fail: if (mapping) | |
b93b0163 | 2781 | xa_unlock(&mapping->i_pages); |
f4b7e272 | 2782 | spin_unlock_irqrestore(&pgdata->lru_lock, flags); |
906f9cdf | 2783 | remap_page(head); |
e9b61f19 KS |
2784 | ret = -EBUSY; |
2785 | } | |
2786 | ||
2787 | out_unlock: | |
baa355fd KS |
2788 | if (anon_vma) { |
2789 | anon_vma_unlock_write(anon_vma); | |
2790 | put_anon_vma(anon_vma); | |
2791 | } | |
2792 | if (mapping) | |
2793 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2794 | out: |
2795 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2796 | return ret; | |
2797 | } | |
9a982250 KS |
2798 | |
2799 | void free_transhuge_page(struct page *page) | |
2800 | { | |
a3d0a918 | 2801 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2802 | unsigned long flags; |
2803 | ||
a3d0a918 | 2804 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2805 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2806 | pgdata->split_queue_len--; |
9a982250 KS |
2807 | list_del(page_deferred_list(page)); |
2808 | } | |
a3d0a918 | 2809 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2810 | free_compound_page(page); |
2811 | } | |
2812 | ||
2813 | void deferred_split_huge_page(struct page *page) | |
2814 | { | |
a3d0a918 | 2815 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2816 | unsigned long flags; |
2817 | ||
2818 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2819 | ||
a3d0a918 | 2820 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2821 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2822 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2823 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2824 | pgdata->split_queue_len++; | |
9a982250 | 2825 | } |
a3d0a918 | 2826 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2827 | } |
2828 | ||
2829 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2830 | struct shrink_control *sc) | |
2831 | { | |
a3d0a918 | 2832 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
6aa7de05 | 2833 | return READ_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2834 | } |
2835 | ||
2836 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2837 | struct shrink_control *sc) | |
2838 | { | |
a3d0a918 | 2839 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2840 | unsigned long flags; |
2841 | LIST_HEAD(list), *pos, *next; | |
2842 | struct page *page; | |
2843 | int split = 0; | |
2844 | ||
a3d0a918 | 2845 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2846 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2847 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2848 | page = list_entry((void *)pos, struct page, mapping); |
2849 | page = compound_head(page); | |
e3ae1953 KS |
2850 | if (get_page_unless_zero(page)) { |
2851 | list_move(page_deferred_list(page), &list); | |
2852 | } else { | |
2853 | /* We lost race with put_compound_page() */ | |
9a982250 | 2854 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2855 | pgdata->split_queue_len--; |
9a982250 | 2856 | } |
e3ae1953 KS |
2857 | if (!--sc->nr_to_scan) |
2858 | break; | |
9a982250 | 2859 | } |
a3d0a918 | 2860 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2861 | |
2862 | list_for_each_safe(pos, next, &list) { | |
2863 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2864 | if (!trylock_page(page)) |
2865 | goto next; | |
9a982250 KS |
2866 | /* split_huge_page() removes page from list on success */ |
2867 | if (!split_huge_page(page)) | |
2868 | split++; | |
2869 | unlock_page(page); | |
fa41b900 | 2870 | next: |
9a982250 KS |
2871 | put_page(page); |
2872 | } | |
2873 | ||
a3d0a918 KS |
2874 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2875 | list_splice_tail(&list, &pgdata->split_queue); | |
2876 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2877 | |
cb8d68ec KS |
2878 | /* |
2879 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2880 | * This can happen if pages were freed under us. | |
2881 | */ | |
2882 | if (!split && list_empty(&pgdata->split_queue)) | |
2883 | return SHRINK_STOP; | |
2884 | return split; | |
9a982250 KS |
2885 | } |
2886 | ||
2887 | static struct shrinker deferred_split_shrinker = { | |
2888 | .count_objects = deferred_split_count, | |
2889 | .scan_objects = deferred_split_scan, | |
2890 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2891 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2892 | }; |
49071d43 KS |
2893 | |
2894 | #ifdef CONFIG_DEBUG_FS | |
2895 | static int split_huge_pages_set(void *data, u64 val) | |
2896 | { | |
2897 | struct zone *zone; | |
2898 | struct page *page; | |
2899 | unsigned long pfn, max_zone_pfn; | |
2900 | unsigned long total = 0, split = 0; | |
2901 | ||
2902 | if (val != 1) | |
2903 | return -EINVAL; | |
2904 | ||
2905 | for_each_populated_zone(zone) { | |
2906 | max_zone_pfn = zone_end_pfn(zone); | |
2907 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2908 | if (!pfn_valid(pfn)) | |
2909 | continue; | |
2910 | ||
2911 | page = pfn_to_page(pfn); | |
2912 | if (!get_page_unless_zero(page)) | |
2913 | continue; | |
2914 | ||
2915 | if (zone != page_zone(page)) | |
2916 | goto next; | |
2917 | ||
baa355fd | 2918 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2919 | goto next; |
2920 | ||
2921 | total++; | |
2922 | lock_page(page); | |
2923 | if (!split_huge_page(page)) | |
2924 | split++; | |
2925 | unlock_page(page); | |
2926 | next: | |
2927 | put_page(page); | |
2928 | } | |
2929 | } | |
2930 | ||
145bdaa1 | 2931 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2932 | |
2933 | return 0; | |
2934 | } | |
2935 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2936 | "%llu\n"); | |
2937 | ||
2938 | static int __init split_huge_pages_debugfs(void) | |
2939 | { | |
d9f7979c GKH |
2940 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
2941 | &split_huge_pages_fops); | |
49071d43 KS |
2942 | return 0; |
2943 | } | |
2944 | late_initcall(split_huge_pages_debugfs); | |
2945 | #endif | |
616b8371 ZY |
2946 | |
2947 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2948 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2949 | struct page *page) | |
2950 | { | |
2951 | struct vm_area_struct *vma = pvmw->vma; | |
2952 | struct mm_struct *mm = vma->vm_mm; | |
2953 | unsigned long address = pvmw->address; | |
2954 | pmd_t pmdval; | |
2955 | swp_entry_t entry; | |
ab6e3d09 | 2956 | pmd_t pmdswp; |
616b8371 ZY |
2957 | |
2958 | if (!(pvmw->pmd && !pvmw->pte)) | |
2959 | return; | |
2960 | ||
616b8371 ZY |
2961 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
2962 | pmdval = *pvmw->pmd; | |
2963 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2964 | if (pmd_dirty(pmdval)) | |
2965 | set_page_dirty(page); | |
2966 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2967 | pmdswp = swp_entry_to_pmd(entry); |
2968 | if (pmd_soft_dirty(pmdval)) | |
2969 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2970 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2971 | page_remove_rmap(page, true); |
2972 | put_page(page); | |
616b8371 ZY |
2973 | } |
2974 | ||
2975 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2976 | { | |
2977 | struct vm_area_struct *vma = pvmw->vma; | |
2978 | struct mm_struct *mm = vma->vm_mm; | |
2979 | unsigned long address = pvmw->address; | |
2980 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2981 | pmd_t pmde; | |
2982 | swp_entry_t entry; | |
2983 | ||
2984 | if (!(pvmw->pmd && !pvmw->pte)) | |
2985 | return; | |
2986 | ||
2987 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2988 | get_page(new); | |
2989 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2990 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2991 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 2992 | if (is_write_migration_entry(entry)) |
f55e1014 | 2993 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
2994 | |
2995 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
2996 | if (PageAnon(new)) |
2997 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2998 | else | |
2999 | page_add_file_rmap(new, true); | |
616b8371 | 3000 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 3001 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
3002 | mlock_vma_page(new); |
3003 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
3004 | } | |
3005 | #endif |