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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> |
97ae1749 | 35 | |
71e3aac0 AA |
36 | #include <asm/tlb.h> |
37 | #include <asm/pgalloc.h> | |
38 | #include "internal.h" | |
39 | ||
ba76149f | 40 | /* |
b14d595a MD |
41 | * By default, transparent hugepage support is disabled in order to avoid |
42 | * risking an increased memory footprint for applications that are not | |
43 | * guaranteed to benefit from it. When transparent hugepage support is | |
44 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
45 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
46 | * for all hugepage allocations. | |
ba76149f | 47 | */ |
71e3aac0 | 48 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 49 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 50 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
51 | #endif |
52 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
53 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
54 | #endif | |
444eb2a4 | 55 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
56 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
57 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 58 | |
9a982250 | 59 | static struct shrinker deferred_split_shrinker; |
f000565a | 60 | |
97ae1749 | 61 | static atomic_t huge_zero_refcount; |
56873f43 | 62 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 63 | |
7635d9cb MH |
64 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
65 | { | |
66 | if (vma_is_anonymous(vma)) | |
67 | return __transparent_hugepage_enabled(vma); | |
68 | if (vma_is_shmem(vma) && shmem_huge_enabled(vma)) | |
69 | return __transparent_hugepage_enabled(vma); | |
70 | ||
71 | return false; | |
72 | } | |
73 | ||
6fcb52a5 | 74 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
75 | { |
76 | struct page *zero_page; | |
77 | retry: | |
78 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 79 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
80 | |
81 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 82 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
83 | if (!zero_page) { |
84 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 85 | return NULL; |
d8a8e1f0 KS |
86 | } |
87 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 88 | preempt_disable(); |
5918d10a | 89 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 90 | preempt_enable(); |
5ddacbe9 | 91 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
92 | goto retry; |
93 | } | |
94 | ||
95 | /* We take additional reference here. It will be put back by shrinker */ | |
96 | atomic_set(&huge_zero_refcount, 2); | |
97 | preempt_enable(); | |
4db0c3c2 | 98 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
99 | } |
100 | ||
6fcb52a5 | 101 | static void put_huge_zero_page(void) |
4a6c1297 | 102 | { |
97ae1749 KS |
103 | /* |
104 | * Counter should never go to zero here. Only shrinker can put | |
105 | * last reference. | |
106 | */ | |
107 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
108 | } |
109 | ||
6fcb52a5 AL |
110 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
111 | { | |
112 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
113 | return READ_ONCE(huge_zero_page); | |
114 | ||
115 | if (!get_huge_zero_page()) | |
116 | return NULL; | |
117 | ||
118 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
119 | put_huge_zero_page(); | |
120 | ||
121 | return READ_ONCE(huge_zero_page); | |
122 | } | |
123 | ||
124 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
125 | { | |
126 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
127 | put_huge_zero_page(); | |
128 | } | |
129 | ||
48896466 GC |
130 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
131 | struct shrink_control *sc) | |
4a6c1297 | 132 | { |
48896466 GC |
133 | /* we can free zero page only if last reference remains */ |
134 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
135 | } | |
97ae1749 | 136 | |
48896466 GC |
137 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
138 | struct shrink_control *sc) | |
139 | { | |
97ae1749 | 140 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
141 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
142 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 143 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 144 | return HPAGE_PMD_NR; |
97ae1749 KS |
145 | } |
146 | ||
147 | return 0; | |
4a6c1297 KS |
148 | } |
149 | ||
97ae1749 | 150 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
151 | .count_objects = shrink_huge_zero_page_count, |
152 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
153 | .seeks = DEFAULT_SEEKS, |
154 | }; | |
155 | ||
71e3aac0 | 156 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
157 | static ssize_t enabled_show(struct kobject *kobj, |
158 | struct kobj_attribute *attr, char *buf) | |
159 | { | |
444eb2a4 MG |
160 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
161 | return sprintf(buf, "[always] madvise never\n"); | |
162 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
163 | return sprintf(buf, "always [madvise] never\n"); | |
164 | else | |
165 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 166 | } |
444eb2a4 | 167 | |
71e3aac0 AA |
168 | static ssize_t enabled_store(struct kobject *kobj, |
169 | struct kobj_attribute *attr, | |
170 | const char *buf, size_t count) | |
171 | { | |
21440d7e | 172 | ssize_t ret = count; |
ba76149f | 173 | |
21440d7e DR |
174 | if (!memcmp("always", buf, |
175 | min(sizeof("always")-1, count))) { | |
176 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
177 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
178 | } else if (!memcmp("madvise", buf, | |
179 | min(sizeof("madvise")-1, count))) { | |
180 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
181 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
182 | } else if (!memcmp("never", buf, | |
183 | min(sizeof("never")-1, count))) { | |
184 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
185 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
186 | } else | |
187 | ret = -EINVAL; | |
ba76149f AA |
188 | |
189 | if (ret > 0) { | |
b46e756f | 190 | int err = start_stop_khugepaged(); |
ba76149f AA |
191 | if (err) |
192 | ret = err; | |
193 | } | |
ba76149f | 194 | return ret; |
71e3aac0 AA |
195 | } |
196 | static struct kobj_attribute enabled_attr = | |
197 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
198 | ||
b46e756f | 199 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
200 | struct kobj_attribute *attr, char *buf, |
201 | enum transparent_hugepage_flag flag) | |
202 | { | |
e27e6151 BH |
203 | return sprintf(buf, "%d\n", |
204 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 205 | } |
e27e6151 | 206 | |
b46e756f | 207 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
208 | struct kobj_attribute *attr, |
209 | const char *buf, size_t count, | |
210 | enum transparent_hugepage_flag flag) | |
211 | { | |
e27e6151 BH |
212 | unsigned long value; |
213 | int ret; | |
214 | ||
215 | ret = kstrtoul(buf, 10, &value); | |
216 | if (ret < 0) | |
217 | return ret; | |
218 | if (value > 1) | |
219 | return -EINVAL; | |
220 | ||
221 | if (value) | |
71e3aac0 | 222 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 223 | else |
71e3aac0 | 224 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
225 | |
226 | return count; | |
227 | } | |
228 | ||
71e3aac0 AA |
229 | static ssize_t defrag_show(struct kobject *kobj, |
230 | struct kobj_attribute *attr, char *buf) | |
231 | { | |
444eb2a4 | 232 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 233 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 234 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
235 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
236 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
237 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
238 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
239 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
240 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 241 | } |
21440d7e | 242 | |
71e3aac0 AA |
243 | static ssize_t defrag_store(struct kobject *kobj, |
244 | struct kobj_attribute *attr, | |
245 | const char *buf, size_t count) | |
246 | { | |
21440d7e DR |
247 | if (!memcmp("always", buf, |
248 | min(sizeof("always")-1, count))) { | |
249 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
250 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
251 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
252 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
253 | } else if (!memcmp("defer+madvise", buf, |
254 | min(sizeof("defer+madvise")-1, count))) { | |
255 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
256 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
257 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
258 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
4fad7fb6 DR |
259 | } else if (!memcmp("defer", buf, |
260 | min(sizeof("defer")-1, count))) { | |
261 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
262 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
263 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
264 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
265 | } else if (!memcmp("madvise", buf, |
266 | min(sizeof("madvise")-1, count))) { | |
267 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
268 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
269 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
270 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
271 | } else if (!memcmp("never", buf, | |
272 | min(sizeof("never")-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 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
277 | } else | |
278 | return -EINVAL; | |
279 | ||
280 | return count; | |
71e3aac0 AA |
281 | } |
282 | static struct kobj_attribute defrag_attr = | |
283 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
284 | ||
79da5407 KS |
285 | static ssize_t use_zero_page_show(struct kobject *kobj, |
286 | struct kobj_attribute *attr, char *buf) | |
287 | { | |
b46e756f | 288 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
289 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
290 | } | |
291 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
292 | struct kobj_attribute *attr, const char *buf, size_t count) | |
293 | { | |
b46e756f | 294 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
295 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
296 | } | |
297 | static struct kobj_attribute use_zero_page_attr = | |
298 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
299 | |
300 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
301 | struct kobj_attribute *attr, char *buf) | |
302 | { | |
303 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
304 | } | |
305 | static struct kobj_attribute hpage_pmd_size_attr = | |
306 | __ATTR_RO(hpage_pmd_size); | |
307 | ||
71e3aac0 AA |
308 | #ifdef CONFIG_DEBUG_VM |
309 | static ssize_t debug_cow_show(struct kobject *kobj, | |
310 | struct kobj_attribute *attr, char *buf) | |
311 | { | |
b46e756f | 312 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
313 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
314 | } | |
315 | static ssize_t debug_cow_store(struct kobject *kobj, | |
316 | struct kobj_attribute *attr, | |
317 | const char *buf, size_t count) | |
318 | { | |
b46e756f | 319 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
320 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
321 | } | |
322 | static struct kobj_attribute debug_cow_attr = | |
323 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
324 | #endif /* CONFIG_DEBUG_VM */ | |
325 | ||
326 | static struct attribute *hugepage_attr[] = { | |
327 | &enabled_attr.attr, | |
328 | &defrag_attr.attr, | |
79da5407 | 329 | &use_zero_page_attr.attr, |
49920d28 | 330 | &hpage_pmd_size_attr.attr, |
e496cf3d | 331 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
332 | &shmem_enabled_attr.attr, |
333 | #endif | |
71e3aac0 AA |
334 | #ifdef CONFIG_DEBUG_VM |
335 | &debug_cow_attr.attr, | |
336 | #endif | |
337 | NULL, | |
338 | }; | |
339 | ||
8aa95a21 | 340 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 341 | .attrs = hugepage_attr, |
ba76149f AA |
342 | }; |
343 | ||
569e5590 | 344 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 345 | { |
71e3aac0 AA |
346 | int err; |
347 | ||
569e5590 SL |
348 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
349 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 350 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 351 | return -ENOMEM; |
ba76149f AA |
352 | } |
353 | ||
569e5590 | 354 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 355 | if (err) { |
ae3a8c1c | 356 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 357 | goto delete_obj; |
ba76149f AA |
358 | } |
359 | ||
569e5590 | 360 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 361 | if (err) { |
ae3a8c1c | 362 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 363 | goto remove_hp_group; |
ba76149f | 364 | } |
569e5590 SL |
365 | |
366 | return 0; | |
367 | ||
368 | remove_hp_group: | |
369 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
370 | delete_obj: | |
371 | kobject_put(*hugepage_kobj); | |
372 | return err; | |
373 | } | |
374 | ||
375 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
376 | { | |
377 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
378 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
379 | kobject_put(hugepage_kobj); | |
380 | } | |
381 | #else | |
382 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
383 | { | |
384 | return 0; | |
385 | } | |
386 | ||
387 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
388 | { | |
389 | } | |
390 | #endif /* CONFIG_SYSFS */ | |
391 | ||
392 | static int __init hugepage_init(void) | |
393 | { | |
394 | int err; | |
395 | struct kobject *hugepage_kobj; | |
396 | ||
397 | if (!has_transparent_hugepage()) { | |
398 | transparent_hugepage_flags = 0; | |
399 | return -EINVAL; | |
400 | } | |
401 | ||
ff20c2e0 KS |
402 | /* |
403 | * hugepages can't be allocated by the buddy allocator | |
404 | */ | |
405 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
406 | /* | |
407 | * we use page->mapping and page->index in second tail page | |
408 | * as list_head: assuming THP order >= 2 | |
409 | */ | |
410 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
411 | ||
569e5590 SL |
412 | err = hugepage_init_sysfs(&hugepage_kobj); |
413 | if (err) | |
65ebb64f | 414 | goto err_sysfs; |
ba76149f | 415 | |
b46e756f | 416 | err = khugepaged_init(); |
ba76149f | 417 | if (err) |
65ebb64f | 418 | goto err_slab; |
ba76149f | 419 | |
65ebb64f KS |
420 | err = register_shrinker(&huge_zero_page_shrinker); |
421 | if (err) | |
422 | goto err_hzp_shrinker; | |
9a982250 KS |
423 | err = register_shrinker(&deferred_split_shrinker); |
424 | if (err) | |
425 | goto err_split_shrinker; | |
97ae1749 | 426 | |
97562cd2 RR |
427 | /* |
428 | * By default disable transparent hugepages on smaller systems, | |
429 | * where the extra memory used could hurt more than TLB overhead | |
430 | * is likely to save. The admin can still enable it through /sys. | |
431 | */ | |
ca79b0c2 | 432 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 433 | transparent_hugepage_flags = 0; |
79553da2 KS |
434 | return 0; |
435 | } | |
97562cd2 | 436 | |
79553da2 | 437 | err = start_stop_khugepaged(); |
65ebb64f KS |
438 | if (err) |
439 | goto err_khugepaged; | |
ba76149f | 440 | |
569e5590 | 441 | return 0; |
65ebb64f | 442 | err_khugepaged: |
9a982250 KS |
443 | unregister_shrinker(&deferred_split_shrinker); |
444 | err_split_shrinker: | |
65ebb64f KS |
445 | unregister_shrinker(&huge_zero_page_shrinker); |
446 | err_hzp_shrinker: | |
b46e756f | 447 | khugepaged_destroy(); |
65ebb64f | 448 | err_slab: |
569e5590 | 449 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 450 | err_sysfs: |
ba76149f | 451 | return err; |
71e3aac0 | 452 | } |
a64fb3cd | 453 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
454 | |
455 | static int __init setup_transparent_hugepage(char *str) | |
456 | { | |
457 | int ret = 0; | |
458 | if (!str) | |
459 | goto out; | |
460 | if (!strcmp(str, "always")) { | |
461 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
462 | &transparent_hugepage_flags); | |
463 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
464 | &transparent_hugepage_flags); | |
465 | ret = 1; | |
466 | } else if (!strcmp(str, "madvise")) { | |
467 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
468 | &transparent_hugepage_flags); | |
469 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
470 | &transparent_hugepage_flags); | |
471 | ret = 1; | |
472 | } else if (!strcmp(str, "never")) { | |
473 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
474 | &transparent_hugepage_flags); | |
475 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
476 | &transparent_hugepage_flags); | |
477 | ret = 1; | |
478 | } | |
479 | out: | |
480 | if (!ret) | |
ae3a8c1c | 481 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
482 | return ret; |
483 | } | |
484 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
485 | ||
f55e1014 | 486 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 487 | { |
f55e1014 | 488 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
489 | pmd = pmd_mkwrite(pmd); |
490 | return pmd; | |
491 | } | |
492 | ||
9a982250 KS |
493 | static inline struct list_head *page_deferred_list(struct page *page) |
494 | { | |
fa3015b7 MW |
495 | /* ->lru in the tail pages is occupied by compound_head. */ |
496 | return &page[2].deferred_list; | |
9a982250 KS |
497 | } |
498 | ||
499 | void prep_transhuge_page(struct page *page) | |
500 | { | |
501 | /* | |
502 | * we use page->mapping and page->indexlru in second tail page | |
503 | * as list_head: assuming THP order >= 2 | |
504 | */ | |
9a982250 KS |
505 | |
506 | INIT_LIST_HEAD(page_deferred_list(page)); | |
507 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
508 | } | |
509 | ||
b3b07077 | 510 | static unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
74d2fad1 TK |
511 | loff_t off, unsigned long flags, unsigned long size) |
512 | { | |
513 | unsigned long addr; | |
514 | loff_t off_end = off + len; | |
515 | loff_t off_align = round_up(off, size); | |
516 | unsigned long len_pad; | |
517 | ||
518 | if (off_end <= off_align || (off_end - off_align) < size) | |
519 | return 0; | |
520 | ||
521 | len_pad = len + size; | |
522 | if (len_pad < len || (off + len_pad) < off) | |
523 | return 0; | |
524 | ||
525 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
526 | off >> PAGE_SHIFT, flags); | |
527 | if (IS_ERR_VALUE(addr)) | |
528 | return 0; | |
529 | ||
530 | addr += (off - addr) & (size - 1); | |
531 | return addr; | |
532 | } | |
533 | ||
534 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
535 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
536 | { | |
537 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
538 | ||
539 | if (addr) | |
540 | goto out; | |
541 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
542 | goto out; | |
543 | ||
544 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
545 | if (addr) | |
546 | return addr; | |
547 | ||
548 | out: | |
549 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
550 | } | |
551 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
552 | ||
2b740303 SJ |
553 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
554 | struct page *page, gfp_t gfp) | |
71e3aac0 | 555 | { |
82b0f8c3 | 556 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 557 | struct mem_cgroup *memcg; |
71e3aac0 | 558 | pgtable_t pgtable; |
82b0f8c3 | 559 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 560 | vm_fault_t ret = 0; |
71e3aac0 | 561 | |
309381fe | 562 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 563 | |
2cf85583 | 564 | if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
565 | put_page(page); |
566 | count_vm_event(THP_FAULT_FALLBACK); | |
567 | return VM_FAULT_FALLBACK; | |
568 | } | |
00501b53 | 569 | |
4cf58924 | 570 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 571 | if (unlikely(!pgtable)) { |
6b31d595 MH |
572 | ret = VM_FAULT_OOM; |
573 | goto release; | |
00501b53 | 574 | } |
71e3aac0 | 575 | |
c79b57e4 | 576 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
577 | /* |
578 | * The memory barrier inside __SetPageUptodate makes sure that | |
579 | * clear_huge_page writes become visible before the set_pmd_at() | |
580 | * write. | |
581 | */ | |
71e3aac0 AA |
582 | __SetPageUptodate(page); |
583 | ||
82b0f8c3 JK |
584 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
585 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 586 | goto unlock_release; |
71e3aac0 AA |
587 | } else { |
588 | pmd_t entry; | |
6b251fc9 | 589 | |
6b31d595 MH |
590 | ret = check_stable_address_space(vma->vm_mm); |
591 | if (ret) | |
592 | goto unlock_release; | |
593 | ||
6b251fc9 AA |
594 | /* Deliver the page fault to userland */ |
595 | if (userfaultfd_missing(vma)) { | |
2b740303 | 596 | vm_fault_t ret2; |
6b251fc9 | 597 | |
82b0f8c3 | 598 | spin_unlock(vmf->ptl); |
f627c2f5 | 599 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 600 | put_page(page); |
bae473a4 | 601 | pte_free(vma->vm_mm, pgtable); |
2b740303 SJ |
602 | ret2 = handle_userfault(vmf, VM_UFFD_MISSING); |
603 | VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); | |
604 | return ret2; | |
6b251fc9 AA |
605 | } |
606 | ||
3122359a | 607 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 608 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 609 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 610 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 611 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
612 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
613 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 614 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 615 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 616 | spin_unlock(vmf->ptl); |
6b251fc9 | 617 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 618 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
71e3aac0 AA |
619 | } |
620 | ||
aa2e878e | 621 | return 0; |
6b31d595 MH |
622 | unlock_release: |
623 | spin_unlock(vmf->ptl); | |
624 | release: | |
625 | if (pgtable) | |
626 | pte_free(vma->vm_mm, pgtable); | |
627 | mem_cgroup_cancel_charge(page, memcg, true); | |
628 | put_page(page); | |
629 | return ret; | |
630 | ||
71e3aac0 AA |
631 | } |
632 | ||
444eb2a4 | 633 | /* |
21440d7e DR |
634 | * always: directly stall for all thp allocations |
635 | * defer: wake kswapd and fail if not immediately available | |
636 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
637 | * fail if not immediately available | |
638 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
639 | * available | |
640 | * never: never stall for any thp allocation | |
444eb2a4 | 641 | */ |
356ff8a9 | 642 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) |
444eb2a4 | 643 | { |
21440d7e | 644 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 645 | |
2f0799a0 | 646 | /* Always do synchronous compaction */ |
21440d7e | 647 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 648 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
2f0799a0 DR |
649 | |
650 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 651 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 652 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
2f0799a0 DR |
653 | |
654 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 655 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
656 | return GFP_TRANSHUGE_LIGHT | |
657 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
658 | __GFP_KSWAPD_RECLAIM); | |
2f0799a0 DR |
659 | |
660 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 661 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
662 | return GFP_TRANSHUGE_LIGHT | |
663 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
2f0799a0 | 664 | |
356ff8a9 | 665 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
666 | } |
667 | ||
c4088ebd | 668 | /* Caller must hold page table lock. */ |
d295e341 | 669 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 670 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 671 | struct page *zero_page) |
fc9fe822 KS |
672 | { |
673 | pmd_t entry; | |
7c414164 AM |
674 | if (!pmd_none(*pmd)) |
675 | return false; | |
5918d10a | 676 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 677 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
678 | if (pgtable) |
679 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 680 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 681 | mm_inc_nr_ptes(mm); |
7c414164 | 682 | return true; |
fc9fe822 KS |
683 | } |
684 | ||
2b740303 | 685 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 686 | { |
82b0f8c3 | 687 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 688 | gfp_t gfp; |
71e3aac0 | 689 | struct page *page; |
82b0f8c3 | 690 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 691 | |
128ec037 | 692 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 693 | return VM_FAULT_FALLBACK; |
128ec037 KS |
694 | if (unlikely(anon_vma_prepare(vma))) |
695 | return VM_FAULT_OOM; | |
6d50e60c | 696 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 697 | return VM_FAULT_OOM; |
82b0f8c3 | 698 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 699 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
700 | transparent_hugepage_use_zero_page()) { |
701 | pgtable_t pgtable; | |
702 | struct page *zero_page; | |
703 | bool set; | |
2b740303 | 704 | vm_fault_t ret; |
4cf58924 | 705 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 706 | if (unlikely(!pgtable)) |
ba76149f | 707 | return VM_FAULT_OOM; |
6fcb52a5 | 708 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 709 | if (unlikely(!zero_page)) { |
bae473a4 | 710 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 711 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 712 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 713 | } |
82b0f8c3 | 714 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
715 | ret = 0; |
716 | set = false; | |
82b0f8c3 | 717 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
718 | ret = check_stable_address_space(vma->vm_mm); |
719 | if (ret) { | |
720 | spin_unlock(vmf->ptl); | |
721 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
722 | spin_unlock(vmf->ptl); |
723 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
724 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
725 | } else { | |
bae473a4 | 726 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
727 | haddr, vmf->pmd, zero_page); |
728 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
729 | set = true; |
730 | } | |
731 | } else | |
82b0f8c3 | 732 | spin_unlock(vmf->ptl); |
6fcb52a5 | 733 | if (!set) |
bae473a4 | 734 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 735 | return ret; |
71e3aac0 | 736 | } |
356ff8a9 DR |
737 | gfp = alloc_hugepage_direct_gfpmask(vma); |
738 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); | |
128ec037 KS |
739 | if (unlikely(!page)) { |
740 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 741 | return VM_FAULT_FALLBACK; |
128ec037 | 742 | } |
9a982250 | 743 | prep_transhuge_page(page); |
82b0f8c3 | 744 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
745 | } |
746 | ||
ae18d6dc | 747 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
748 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
749 | pgtable_t pgtable) | |
5cad465d MW |
750 | { |
751 | struct mm_struct *mm = vma->vm_mm; | |
752 | pmd_t entry; | |
753 | spinlock_t *ptl; | |
754 | ||
755 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
756 | if (!pmd_none(*pmd)) { |
757 | if (write) { | |
758 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
759 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
760 | goto out_unlock; | |
761 | } | |
762 | entry = pmd_mkyoung(*pmd); | |
763 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
764 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
765 | update_mmu_cache_pmd(vma, addr, pmd); | |
766 | } | |
767 | ||
768 | goto out_unlock; | |
769 | } | |
770 | ||
f25748e3 DW |
771 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
772 | if (pfn_t_devmap(pfn)) | |
773 | entry = pmd_mkdevmap(entry); | |
01871e59 | 774 | if (write) { |
f55e1014 LT |
775 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
776 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 777 | } |
3b6521f5 OH |
778 | |
779 | if (pgtable) { | |
780 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 781 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 782 | pgtable = NULL; |
3b6521f5 OH |
783 | } |
784 | ||
01871e59 RZ |
785 | set_pmd_at(mm, addr, pmd, entry); |
786 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
787 | |
788 | out_unlock: | |
5cad465d | 789 | spin_unlock(ptl); |
c6f3c5ee AK |
790 | if (pgtable) |
791 | pte_free(mm, pgtable); | |
5cad465d MW |
792 | } |
793 | ||
fce86ff5 | 794 | vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) |
5cad465d | 795 | { |
fce86ff5 DW |
796 | unsigned long addr = vmf->address & PMD_MASK; |
797 | struct vm_area_struct *vma = vmf->vma; | |
5cad465d | 798 | pgprot_t pgprot = vma->vm_page_prot; |
3b6521f5 | 799 | pgtable_t pgtable = NULL; |
fce86ff5 | 800 | |
5cad465d MW |
801 | /* |
802 | * If we had pmd_special, we could avoid all these restrictions, | |
803 | * but we need to be consistent with PTEs and architectures that | |
804 | * can't support a 'special' bit. | |
805 | */ | |
e1fb4a08 DJ |
806 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
807 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
808 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
809 | (VM_PFNMAP|VM_MIXEDMAP)); | |
810 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
811 | |
812 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
813 | return VM_FAULT_SIGBUS; | |
308a047c | 814 | |
3b6521f5 | 815 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 816 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
817 | if (!pgtable) |
818 | return VM_FAULT_OOM; | |
819 | } | |
820 | ||
308a047c BP |
821 | track_pfn_insert(vma, &pgprot, pfn); |
822 | ||
fce86ff5 | 823 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 824 | return VM_FAULT_NOPAGE; |
5cad465d | 825 | } |
dee41079 | 826 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 827 | |
a00cc7d9 | 828 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 829 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 830 | { |
f55e1014 | 831 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
832 | pud = pud_mkwrite(pud); |
833 | return pud; | |
834 | } | |
835 | ||
836 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
837 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
838 | { | |
839 | struct mm_struct *mm = vma->vm_mm; | |
840 | pud_t entry; | |
841 | spinlock_t *ptl; | |
842 | ||
843 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
844 | if (!pud_none(*pud)) { |
845 | if (write) { | |
846 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
847 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
848 | goto out_unlock; | |
849 | } | |
850 | entry = pud_mkyoung(*pud); | |
851 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
852 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
853 | update_mmu_cache_pud(vma, addr, pud); | |
854 | } | |
855 | goto out_unlock; | |
856 | } | |
857 | ||
a00cc7d9 MW |
858 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
859 | if (pfn_t_devmap(pfn)) | |
860 | entry = pud_mkdevmap(entry); | |
861 | if (write) { | |
f55e1014 LT |
862 | entry = pud_mkyoung(pud_mkdirty(entry)); |
863 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
864 | } |
865 | set_pud_at(mm, addr, pud, entry); | |
866 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
867 | |
868 | out_unlock: | |
a00cc7d9 MW |
869 | spin_unlock(ptl); |
870 | } | |
871 | ||
fce86ff5 | 872 | vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) |
a00cc7d9 | 873 | { |
fce86ff5 DW |
874 | unsigned long addr = vmf->address & PUD_MASK; |
875 | struct vm_area_struct *vma = vmf->vma; | |
a00cc7d9 | 876 | pgprot_t pgprot = vma->vm_page_prot; |
fce86ff5 | 877 | |
a00cc7d9 MW |
878 | /* |
879 | * If we had pud_special, we could avoid all these restrictions, | |
880 | * but we need to be consistent with PTEs and architectures that | |
881 | * can't support a 'special' bit. | |
882 | */ | |
62ec0d8c DJ |
883 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
884 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
885 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
886 | (VM_PFNMAP|VM_MIXEDMAP)); | |
887 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
888 | |
889 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
890 | return VM_FAULT_SIGBUS; | |
891 | ||
892 | track_pfn_insert(vma, &pgprot, pfn); | |
893 | ||
fce86ff5 | 894 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
895 | return VM_FAULT_NOPAGE; |
896 | } | |
897 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
898 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
899 | ||
3565fce3 | 900 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 901 | pmd_t *pmd, int flags) |
3565fce3 DW |
902 | { |
903 | pmd_t _pmd; | |
904 | ||
a8f97366 KS |
905 | _pmd = pmd_mkyoung(*pmd); |
906 | if (flags & FOLL_WRITE) | |
907 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 908 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 909 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
910 | update_mmu_cache_pmd(vma, addr, pmd); |
911 | } | |
912 | ||
913 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 914 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
915 | { |
916 | unsigned long pfn = pmd_pfn(*pmd); | |
917 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
918 | struct page *page; |
919 | ||
920 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
921 | ||
8310d48b KF |
922 | /* |
923 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
924 | * not be in this function with `flags & FOLL_COW` set. | |
925 | */ | |
926 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
927 | ||
f6f37321 | 928 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
929 | return NULL; |
930 | ||
931 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
932 | /* pass */; | |
933 | else | |
934 | return NULL; | |
935 | ||
936 | if (flags & FOLL_TOUCH) | |
a8f97366 | 937 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
938 | |
939 | /* | |
940 | * device mapped pages can only be returned if the | |
941 | * caller will manage the page reference count. | |
942 | */ | |
943 | if (!(flags & FOLL_GET)) | |
944 | return ERR_PTR(-EEXIST); | |
945 | ||
946 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
947 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
948 | if (!*pgmap) | |
3565fce3 DW |
949 | return ERR_PTR(-EFAULT); |
950 | page = pfn_to_page(pfn); | |
951 | get_page(page); | |
3565fce3 DW |
952 | |
953 | return page; | |
954 | } | |
955 | ||
71e3aac0 AA |
956 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
957 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
958 | struct vm_area_struct *vma) | |
959 | { | |
c4088ebd | 960 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
961 | struct page *src_page; |
962 | pmd_t pmd; | |
12c9d70b | 963 | pgtable_t pgtable = NULL; |
628d47ce | 964 | int ret = -ENOMEM; |
71e3aac0 | 965 | |
628d47ce KS |
966 | /* Skip if can be re-fill on fault */ |
967 | if (!vma_is_anonymous(vma)) | |
968 | return 0; | |
969 | ||
4cf58924 | 970 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
971 | if (unlikely(!pgtable)) |
972 | goto out; | |
71e3aac0 | 973 | |
c4088ebd KS |
974 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
975 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
976 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
977 | |
978 | ret = -EAGAIN; | |
979 | pmd = *src_pmd; | |
84c3fc4e ZY |
980 | |
981 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
982 | if (unlikely(is_swap_pmd(pmd))) { | |
983 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
984 | ||
985 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
986 | if (is_write_migration_entry(entry)) { | |
987 | make_migration_entry_read(&entry); | |
988 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
989 | if (pmd_swp_soft_dirty(*src_pmd)) |
990 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
991 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
992 | } | |
dd8a67f9 | 993 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 994 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 995 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
996 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
997 | ret = 0; | |
998 | goto out_unlock; | |
999 | } | |
1000 | #endif | |
1001 | ||
628d47ce | 1002 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1003 | pte_free(dst_mm, pgtable); |
1004 | goto out_unlock; | |
1005 | } | |
fc9fe822 | 1006 | /* |
c4088ebd | 1007 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1008 | * under splitting since we don't split the page itself, only pmd to |
1009 | * a page table. | |
1010 | */ | |
1011 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 1012 | struct page *zero_page; |
97ae1749 KS |
1013 | /* |
1014 | * get_huge_zero_page() will never allocate a new page here, | |
1015 | * since we already have a zero page to copy. It just takes a | |
1016 | * reference. | |
1017 | */ | |
6fcb52a5 | 1018 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 1019 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 1020 | zero_page); |
fc9fe822 KS |
1021 | ret = 0; |
1022 | goto out_unlock; | |
1023 | } | |
de466bd6 | 1024 | |
628d47ce KS |
1025 | src_page = pmd_page(pmd); |
1026 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
1027 | get_page(src_page); | |
1028 | page_dup_rmap(src_page, true); | |
1029 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 1030 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1031 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
1032 | |
1033 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
1034 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
1035 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1036 | |
1037 | ret = 0; | |
1038 | out_unlock: | |
c4088ebd KS |
1039 | spin_unlock(src_ptl); |
1040 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1041 | out: |
1042 | return ret; | |
1043 | } | |
1044 | ||
a00cc7d9 MW |
1045 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1046 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1047 | pud_t *pud, int flags) |
a00cc7d9 MW |
1048 | { |
1049 | pud_t _pud; | |
1050 | ||
a8f97366 KS |
1051 | _pud = pud_mkyoung(*pud); |
1052 | if (flags & FOLL_WRITE) | |
1053 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1054 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1055 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1056 | update_mmu_cache_pud(vma, addr, pud); |
1057 | } | |
1058 | ||
1059 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1060 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1061 | { |
1062 | unsigned long pfn = pud_pfn(*pud); | |
1063 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1064 | struct page *page; |
1065 | ||
1066 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1067 | ||
f6f37321 | 1068 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1069 | return NULL; |
1070 | ||
1071 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1072 | /* pass */; | |
1073 | else | |
1074 | return NULL; | |
1075 | ||
1076 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1077 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1078 | |
1079 | /* | |
1080 | * device mapped pages can only be returned if the | |
1081 | * caller will manage the page reference count. | |
1082 | */ | |
1083 | if (!(flags & FOLL_GET)) | |
1084 | return ERR_PTR(-EEXIST); | |
1085 | ||
1086 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1087 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1088 | if (!*pgmap) | |
a00cc7d9 MW |
1089 | return ERR_PTR(-EFAULT); |
1090 | page = pfn_to_page(pfn); | |
1091 | get_page(page); | |
a00cc7d9 MW |
1092 | |
1093 | return page; | |
1094 | } | |
1095 | ||
1096 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1097 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1098 | struct vm_area_struct *vma) | |
1099 | { | |
1100 | spinlock_t *dst_ptl, *src_ptl; | |
1101 | pud_t pud; | |
1102 | int ret; | |
1103 | ||
1104 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1105 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1106 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1107 | ||
1108 | ret = -EAGAIN; | |
1109 | pud = *src_pud; | |
1110 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1111 | goto out_unlock; | |
1112 | ||
1113 | /* | |
1114 | * When page table lock is held, the huge zero pud should not be | |
1115 | * under splitting since we don't split the page itself, only pud to | |
1116 | * a page table. | |
1117 | */ | |
1118 | if (is_huge_zero_pud(pud)) { | |
1119 | /* No huge zero pud yet */ | |
1120 | } | |
1121 | ||
1122 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1123 | pud = pud_mkold(pud_wrprotect(pud)); | |
1124 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1125 | ||
1126 | ret = 0; | |
1127 | out_unlock: | |
1128 | spin_unlock(src_ptl); | |
1129 | spin_unlock(dst_ptl); | |
1130 | return ret; | |
1131 | } | |
1132 | ||
1133 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1134 | { | |
1135 | pud_t entry; | |
1136 | unsigned long haddr; | |
1137 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1138 | ||
1139 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1140 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1141 | goto unlock; | |
1142 | ||
1143 | entry = pud_mkyoung(orig_pud); | |
1144 | if (write) | |
1145 | entry = pud_mkdirty(entry); | |
1146 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1147 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1148 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1149 | ||
1150 | unlock: | |
1151 | spin_unlock(vmf->ptl); | |
1152 | } | |
1153 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1154 | ||
82b0f8c3 | 1155 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1156 | { |
1157 | pmd_t entry; | |
1158 | unsigned long haddr; | |
20f664aa | 1159 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1160 | |
82b0f8c3 JK |
1161 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1162 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1163 | goto unlock; |
1164 | ||
1165 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1166 | if (write) |
1167 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1168 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1169 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1170 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1171 | |
1172 | unlock: | |
82b0f8c3 | 1173 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1174 | } |
1175 | ||
2b740303 SJ |
1176 | static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, |
1177 | pmd_t orig_pmd, struct page *page) | |
71e3aac0 | 1178 | { |
82b0f8c3 JK |
1179 | struct vm_area_struct *vma = vmf->vma; |
1180 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1181 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1182 | pgtable_t pgtable; |
1183 | pmd_t _pmd; | |
2b740303 SJ |
1184 | int i; |
1185 | vm_fault_t ret = 0; | |
71e3aac0 | 1186 | struct page **pages; |
ac46d4f3 | 1187 | struct mmu_notifier_range range; |
71e3aac0 | 1188 | |
6da2ec56 KC |
1189 | pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), |
1190 | GFP_KERNEL); | |
71e3aac0 AA |
1191 | if (unlikely(!pages)) { |
1192 | ret |= VM_FAULT_OOM; | |
1193 | goto out; | |
1194 | } | |
1195 | ||
1196 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1197 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1198 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1199 | if (unlikely(!pages[i] || |
2cf85583 | 1200 | mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, |
bae473a4 | 1201 | GFP_KERNEL, &memcg, false))) { |
b9bbfbe3 | 1202 | if (pages[i]) |
71e3aac0 | 1203 | put_page(pages[i]); |
b9bbfbe3 | 1204 | while (--i >= 0) { |
00501b53 JW |
1205 | memcg = (void *)page_private(pages[i]); |
1206 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1207 | mem_cgroup_cancel_charge(pages[i], memcg, |
1208 | false); | |
b9bbfbe3 AA |
1209 | put_page(pages[i]); |
1210 | } | |
71e3aac0 AA |
1211 | kfree(pages); |
1212 | ret |= VM_FAULT_OOM; | |
1213 | goto out; | |
1214 | } | |
00501b53 | 1215 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1216 | } |
1217 | ||
1218 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1219 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1220 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1221 | __SetPageUptodate(pages[i]); |
1222 | cond_resched(); | |
1223 | } | |
1224 | ||
7269f999 JG |
1225 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1226 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1227 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1228 | |
82b0f8c3 JK |
1229 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1230 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1231 | goto out_free_pages; |
309381fe | 1232 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1233 | |
0f10851e JG |
1234 | /* |
1235 | * Leave pmd empty until pte is filled note we must notify here as | |
1236 | * concurrent CPU thread might write to new page before the call to | |
1237 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1238 | * device seeing memory write in different order than CPU. | |
1239 | * | |
ad56b738 | 1240 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 1241 | */ |
82b0f8c3 | 1242 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1243 | |
82b0f8c3 | 1244 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1245 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1246 | |
1247 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1248 | pte_t entry; |
71e3aac0 AA |
1249 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1250 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1251 | memcg = (void *)page_private(pages[i]); |
1252 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1253 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1254 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1255 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1256 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1257 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1258 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1259 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1260 | } |
1261 | kfree(pages); | |
1262 | ||
71e3aac0 | 1263 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1264 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1265 | page_remove_rmap(page, true); |
82b0f8c3 | 1266 | spin_unlock(vmf->ptl); |
71e3aac0 | 1267 | |
4645b9fe JG |
1268 | /* |
1269 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1270 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1271 | */ | |
ac46d4f3 | 1272 | mmu_notifier_invalidate_range_only_end(&range); |
2ec74c3e | 1273 | |
71e3aac0 AA |
1274 | ret |= VM_FAULT_WRITE; |
1275 | put_page(page); | |
1276 | ||
1277 | out: | |
1278 | return ret; | |
1279 | ||
1280 | out_free_pages: | |
82b0f8c3 | 1281 | spin_unlock(vmf->ptl); |
ac46d4f3 | 1282 | mmu_notifier_invalidate_range_end(&range); |
b9bbfbe3 | 1283 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1284 | memcg = (void *)page_private(pages[i]); |
1285 | set_page_private(pages[i], 0); | |
f627c2f5 | 1286 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1287 | put_page(pages[i]); |
b9bbfbe3 | 1288 | } |
71e3aac0 AA |
1289 | kfree(pages); |
1290 | goto out; | |
1291 | } | |
1292 | ||
2b740303 | 1293 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1294 | { |
82b0f8c3 | 1295 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1296 | struct page *page = NULL, *new_page; |
00501b53 | 1297 | struct mem_cgroup *memcg; |
82b0f8c3 | 1298 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
ac46d4f3 | 1299 | struct mmu_notifier_range range; |
3b363692 | 1300 | gfp_t huge_gfp; /* for allocation and charge */ |
2b740303 | 1301 | vm_fault_t ret = 0; |
71e3aac0 | 1302 | |
82b0f8c3 | 1303 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1304 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1305 | if (is_huge_zero_pmd(orig_pmd)) |
1306 | goto alloc; | |
82b0f8c3 JK |
1307 | spin_lock(vmf->ptl); |
1308 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1309 | goto out_unlock; |
1310 | ||
1311 | page = pmd_page(orig_pmd); | |
309381fe | 1312 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1313 | /* |
1314 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1315 | * part. |
1f25fe20 | 1316 | */ |
ba3c4ce6 HY |
1317 | if (!trylock_page(page)) { |
1318 | get_page(page); | |
1319 | spin_unlock(vmf->ptl); | |
1320 | lock_page(page); | |
1321 | spin_lock(vmf->ptl); | |
1322 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1323 | unlock_page(page); | |
1324 | put_page(page); | |
1325 | goto out_unlock; | |
1326 | } | |
1327 | put_page(page); | |
1328 | } | |
1329 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1330 | pmd_t entry; |
1331 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1332 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1333 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1334 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1335 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1336 | unlock_page(page); |
71e3aac0 AA |
1337 | goto out_unlock; |
1338 | } | |
ba3c4ce6 | 1339 | unlock_page(page); |
ddc58f27 | 1340 | get_page(page); |
82b0f8c3 | 1341 | spin_unlock(vmf->ptl); |
93b4796d | 1342 | alloc: |
7635d9cb | 1343 | if (__transparent_hugepage_enabled(vma) && |
077fcf11 | 1344 | !transparent_hugepage_debug_cow()) { |
356ff8a9 DR |
1345 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
1346 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); | |
077fcf11 | 1347 | } else |
71e3aac0 AA |
1348 | new_page = NULL; |
1349 | ||
9a982250 KS |
1350 | if (likely(new_page)) { |
1351 | prep_transhuge_page(new_page); | |
1352 | } else { | |
eecc1e42 | 1353 | if (!page) { |
82b0f8c3 | 1354 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1355 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1356 | } else { |
82b0f8c3 | 1357 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1358 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1359 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1360 | ret |= VM_FAULT_FALLBACK; |
1361 | } | |
ddc58f27 | 1362 | put_page(page); |
93b4796d | 1363 | } |
17766dde | 1364 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1365 | goto out; |
1366 | } | |
1367 | ||
2cf85583 | 1368 | if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, |
2a70f6a7 | 1369 | huge_gfp, &memcg, true))) { |
b9bbfbe3 | 1370 | put_page(new_page); |
82b0f8c3 | 1371 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1372 | if (page) |
ddc58f27 | 1373 | put_page(page); |
9845cbbd | 1374 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1375 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1376 | goto out; |
1377 | } | |
1378 | ||
17766dde | 1379 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 1380 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
17766dde | 1381 | |
eecc1e42 | 1382 | if (!page) |
c79b57e4 | 1383 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d | 1384 | else |
c9f4cd71 HY |
1385 | copy_user_huge_page(new_page, page, vmf->address, |
1386 | vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1387 | __SetPageUptodate(new_page); |
1388 | ||
7269f999 JG |
1389 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1390 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1391 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1392 | |
82b0f8c3 | 1393 | spin_lock(vmf->ptl); |
93b4796d | 1394 | if (page) |
ddc58f27 | 1395 | put_page(page); |
82b0f8c3 JK |
1396 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1397 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1398 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1399 | put_page(new_page); |
2ec74c3e | 1400 | goto out_mn; |
b9bbfbe3 | 1401 | } else { |
71e3aac0 | 1402 | pmd_t entry; |
3122359a | 1403 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
f55e1014 | 1404 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 | 1405 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1406 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1407 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1408 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1409 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1410 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1411 | if (!page) { |
bae473a4 | 1412 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1413 | } else { |
309381fe | 1414 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1415 | page_remove_rmap(page, true); |
93b4796d KS |
1416 | put_page(page); |
1417 | } | |
71e3aac0 AA |
1418 | ret |= VM_FAULT_WRITE; |
1419 | } | |
82b0f8c3 | 1420 | spin_unlock(vmf->ptl); |
2ec74c3e | 1421 | out_mn: |
4645b9fe JG |
1422 | /* |
1423 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1424 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1425 | */ | |
ac46d4f3 | 1426 | mmu_notifier_invalidate_range_only_end(&range); |
71e3aac0 AA |
1427 | out: |
1428 | return ret; | |
2ec74c3e | 1429 | out_unlock: |
82b0f8c3 | 1430 | spin_unlock(vmf->ptl); |
2ec74c3e | 1431 | return ret; |
71e3aac0 AA |
1432 | } |
1433 | ||
8310d48b KF |
1434 | /* |
1435 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1436 | * after we've gone through a COW cycle and they are dirty. | |
1437 | */ | |
1438 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1439 | { | |
f6f37321 | 1440 | return pmd_write(pmd) || |
8310d48b KF |
1441 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); |
1442 | } | |
1443 | ||
b676b293 | 1444 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1445 | unsigned long addr, |
1446 | pmd_t *pmd, | |
1447 | unsigned int flags) | |
1448 | { | |
b676b293 | 1449 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1450 | struct page *page = NULL; |
1451 | ||
c4088ebd | 1452 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1453 | |
8310d48b | 1454 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1455 | goto out; |
1456 | ||
85facf25 KS |
1457 | /* Avoid dumping huge zero page */ |
1458 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1459 | return ERR_PTR(-EFAULT); | |
1460 | ||
2b4847e7 | 1461 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1462 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1463 | goto out; |
1464 | ||
71e3aac0 | 1465 | page = pmd_page(*pmd); |
ca120cf6 | 1466 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1467 | if (flags & FOLL_TOUCH) |
a8f97366 | 1468 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1469 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1470 | /* |
1471 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1472 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1473 | * | |
9a73f61b KS |
1474 | * For anon THP: |
1475 | * | |
e90309c9 KS |
1476 | * In most cases the pmd is the only mapping of the page as we |
1477 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1478 | * writable private mappings in populate_vma_page_range(). | |
1479 | * | |
1480 | * The only scenario when we have the page shared here is if we | |
1481 | * mlocking read-only mapping shared over fork(). We skip | |
1482 | * mlocking such pages. | |
9a73f61b KS |
1483 | * |
1484 | * For file THP: | |
1485 | * | |
1486 | * We can expect PageDoubleMap() to be stable under page lock: | |
1487 | * for file pages we set it in page_add_file_rmap(), which | |
1488 | * requires page to be locked. | |
e90309c9 | 1489 | */ |
9a73f61b KS |
1490 | |
1491 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1492 | goto skip_mlock; | |
1493 | if (PageDoubleMap(page) || !page->mapping) | |
1494 | goto skip_mlock; | |
1495 | if (!trylock_page(page)) | |
1496 | goto skip_mlock; | |
1497 | lru_add_drain(); | |
1498 | if (page->mapping && !PageDoubleMap(page)) | |
1499 | mlock_vma_page(page); | |
1500 | unlock_page(page); | |
b676b293 | 1501 | } |
9a73f61b | 1502 | skip_mlock: |
71e3aac0 | 1503 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1504 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1505 | if (flags & FOLL_GET) |
ddc58f27 | 1506 | get_page(page); |
71e3aac0 AA |
1507 | |
1508 | out: | |
1509 | return page; | |
1510 | } | |
1511 | ||
d10e63f2 | 1512 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1513 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1514 | { |
82b0f8c3 | 1515 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1516 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1517 | struct page *page; |
82b0f8c3 | 1518 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1519 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1520 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1521 | bool page_locked; |
1522 | bool migrated = false; | |
b191f9b1 | 1523 | bool was_writable; |
6688cc05 | 1524 | int flags = 0; |
d10e63f2 | 1525 | |
82b0f8c3 JK |
1526 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1527 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1528 | goto out_unlock; |
1529 | ||
de466bd6 MG |
1530 | /* |
1531 | * If there are potential migrations, wait for completion and retry | |
1532 | * without disrupting NUMA hinting information. Do not relock and | |
1533 | * check_same as the page may no longer be mapped. | |
1534 | */ | |
82b0f8c3 JK |
1535 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1536 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1537 | if (!get_page_unless_zero(page)) |
1538 | goto out_unlock; | |
82b0f8c3 | 1539 | spin_unlock(vmf->ptl); |
9a1ea439 | 1540 | put_and_wait_on_page_locked(page); |
de466bd6 MG |
1541 | goto out; |
1542 | } | |
1543 | ||
d10e63f2 | 1544 | page = pmd_page(pmd); |
a1a46184 | 1545 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1546 | page_nid = page_to_nid(page); |
90572890 | 1547 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1548 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1549 | if (page_nid == this_nid) { |
03c5a6e1 | 1550 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1551 | flags |= TNF_FAULT_LOCAL; |
1552 | } | |
4daae3b4 | 1553 | |
bea66fbd | 1554 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1555 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1556 | flags |= TNF_NO_GROUP; |
1557 | ||
ff9042b1 MG |
1558 | /* |
1559 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1560 | * page_table_lock if at all possible | |
1561 | */ | |
b8916634 MG |
1562 | page_locked = trylock_page(page); |
1563 | target_nid = mpol_misplaced(page, vma, haddr); | |
98fa15f3 | 1564 | if (target_nid == NUMA_NO_NODE) { |
b8916634 | 1565 | /* If the page was locked, there are no parallel migrations */ |
a54a407f | 1566 | if (page_locked) |
b8916634 | 1567 | goto clear_pmdnuma; |
2b4847e7 | 1568 | } |
4daae3b4 | 1569 | |
de466bd6 | 1570 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1571 | if (!page_locked) { |
98fa15f3 | 1572 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1573 | if (!get_page_unless_zero(page)) |
1574 | goto out_unlock; | |
82b0f8c3 | 1575 | spin_unlock(vmf->ptl); |
9a1ea439 | 1576 | put_and_wait_on_page_locked(page); |
b8916634 MG |
1577 | goto out; |
1578 | } | |
1579 | ||
2b4847e7 MG |
1580 | /* |
1581 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1582 | * to serialises splits | |
1583 | */ | |
b8916634 | 1584 | get_page(page); |
82b0f8c3 | 1585 | spin_unlock(vmf->ptl); |
b8916634 | 1586 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1587 | |
c69307d5 | 1588 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1589 | spin_lock(vmf->ptl); |
1590 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1591 | unlock_page(page); |
1592 | put_page(page); | |
98fa15f3 | 1593 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1594 | goto out_unlock; |
b32967ff | 1595 | } |
ff9042b1 | 1596 | |
c3a489ca MG |
1597 | /* Bail if we fail to protect against THP splits for any reason */ |
1598 | if (unlikely(!anon_vma)) { | |
1599 | put_page(page); | |
98fa15f3 | 1600 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1601 | goto clear_pmdnuma; |
1602 | } | |
1603 | ||
8b1b436d PZ |
1604 | /* |
1605 | * Since we took the NUMA fault, we must have observed the !accessible | |
1606 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1607 | * modifying the page we're about to migrate. | |
1608 | * | |
1609 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1610 | * inc_tlb_flush_pending(). |
1611 | * | |
1612 | * We are not sure a pending tlb flush here is for a huge page | |
1613 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1614 | */ |
7066f0f9 | 1615 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1616 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1617 | /* |
1618 | * change_huge_pmd() released the pmd lock before | |
1619 | * invalidating the secondary MMUs sharing the primary | |
1620 | * MMU pagetables (with ->invalidate_range()). The | |
1621 | * mmu_notifier_invalidate_range_end() (which | |
1622 | * internally calls ->invalidate_range()) in | |
1623 | * change_pmd_range() will run after us, so we can't | |
1624 | * rely on it here and we need an explicit invalidate. | |
1625 | */ | |
1626 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1627 | haddr + HPAGE_PMD_SIZE); | |
1628 | } | |
8b1b436d | 1629 | |
a54a407f MG |
1630 | /* |
1631 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1632 | * and access rights restored. |
a54a407f | 1633 | */ |
82b0f8c3 | 1634 | spin_unlock(vmf->ptl); |
8b1b436d | 1635 | |
bae473a4 | 1636 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1637 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1638 | if (migrated) { |
1639 | flags |= TNF_MIGRATED; | |
8191acbd | 1640 | page_nid = target_nid; |
074c2381 MG |
1641 | } else |
1642 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1643 | |
8191acbd | 1644 | goto out; |
b32967ff | 1645 | clear_pmdnuma: |
a54a407f | 1646 | BUG_ON(!PageLocked(page)); |
288bc549 | 1647 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1648 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1649 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1650 | if (was_writable) |
1651 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1652 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1653 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1654 | unlock_page(page); |
d10e63f2 | 1655 | out_unlock: |
82b0f8c3 | 1656 | spin_unlock(vmf->ptl); |
b8916634 MG |
1657 | |
1658 | out: | |
1659 | if (anon_vma) | |
1660 | page_unlock_anon_vma_read(anon_vma); | |
1661 | ||
98fa15f3 | 1662 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1663 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1664 | flags); |
8191acbd | 1665 | |
d10e63f2 MG |
1666 | return 0; |
1667 | } | |
1668 | ||
319904ad HY |
1669 | /* |
1670 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1671 | * Otherwise, return false. | |
1672 | */ | |
1673 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1674 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1675 | { |
1676 | spinlock_t *ptl; | |
1677 | pmd_t orig_pmd; | |
1678 | struct page *page; | |
1679 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1680 | bool ret = false; |
b8d3c4c3 | 1681 | |
ed6a7935 | 1682 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1683 | |
b6ec57f4 KS |
1684 | ptl = pmd_trans_huge_lock(pmd, vma); |
1685 | if (!ptl) | |
25eedabe | 1686 | goto out_unlocked; |
b8d3c4c3 MK |
1687 | |
1688 | orig_pmd = *pmd; | |
319904ad | 1689 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1690 | goto out; |
b8d3c4c3 | 1691 | |
84c3fc4e ZY |
1692 | if (unlikely(!pmd_present(orig_pmd))) { |
1693 | VM_BUG_ON(thp_migration_supported() && | |
1694 | !is_pmd_migration_entry(orig_pmd)); | |
1695 | goto out; | |
1696 | } | |
1697 | ||
b8d3c4c3 MK |
1698 | page = pmd_page(orig_pmd); |
1699 | /* | |
1700 | * If other processes are mapping this page, we couldn't discard | |
1701 | * the page unless they all do MADV_FREE so let's skip the page. | |
1702 | */ | |
1703 | if (page_mapcount(page) != 1) | |
1704 | goto out; | |
1705 | ||
1706 | if (!trylock_page(page)) | |
1707 | goto out; | |
1708 | ||
1709 | /* | |
1710 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1711 | * will deactivate only them. | |
1712 | */ | |
1713 | if (next - addr != HPAGE_PMD_SIZE) { | |
1714 | get_page(page); | |
1715 | spin_unlock(ptl); | |
9818b8cd | 1716 | split_huge_page(page); |
b8d3c4c3 | 1717 | unlock_page(page); |
bbf29ffc | 1718 | put_page(page); |
b8d3c4c3 MK |
1719 | goto out_unlocked; |
1720 | } | |
1721 | ||
1722 | if (PageDirty(page)) | |
1723 | ClearPageDirty(page); | |
1724 | unlock_page(page); | |
1725 | ||
b8d3c4c3 | 1726 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1727 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1728 | orig_pmd = pmd_mkold(orig_pmd); |
1729 | orig_pmd = pmd_mkclean(orig_pmd); | |
1730 | ||
1731 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1732 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1733 | } | |
802a3a92 SL |
1734 | |
1735 | mark_page_lazyfree(page); | |
319904ad | 1736 | ret = true; |
b8d3c4c3 MK |
1737 | out: |
1738 | spin_unlock(ptl); | |
1739 | out_unlocked: | |
1740 | return ret; | |
1741 | } | |
1742 | ||
953c66c2 AK |
1743 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1744 | { | |
1745 | pgtable_t pgtable; | |
1746 | ||
1747 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1748 | pte_free(mm, pgtable); | |
c4812909 | 1749 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1750 | } |
1751 | ||
71e3aac0 | 1752 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1753 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1754 | { |
da146769 | 1755 | pmd_t orig_pmd; |
bf929152 | 1756 | spinlock_t *ptl; |
71e3aac0 | 1757 | |
ed6a7935 | 1758 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1759 | |
b6ec57f4 KS |
1760 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1761 | if (!ptl) | |
da146769 KS |
1762 | return 0; |
1763 | /* | |
1764 | * For architectures like ppc64 we look at deposited pgtable | |
1765 | * when calling pmdp_huge_get_and_clear. So do the | |
1766 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1767 | * operations. | |
1768 | */ | |
1769 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1770 | tlb->fullmm); | |
1771 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1772 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1773 | if (arch_needs_pgtable_deposit()) |
1774 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1775 | spin_unlock(ptl); |
1776 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1777 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1778 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1779 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1780 | spin_unlock(ptl); |
c0f2e176 | 1781 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1782 | } else { |
616b8371 ZY |
1783 | struct page *page = NULL; |
1784 | int flush_needed = 1; | |
1785 | ||
1786 | if (pmd_present(orig_pmd)) { | |
1787 | page = pmd_page(orig_pmd); | |
1788 | page_remove_rmap(page, true); | |
1789 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1790 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1791 | } else if (thp_migration_supported()) { | |
1792 | swp_entry_t entry; | |
1793 | ||
1794 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1795 | entry = pmd_to_swp_entry(orig_pmd); | |
1796 | page = pfn_to_page(swp_offset(entry)); | |
1797 | flush_needed = 0; | |
1798 | } else | |
1799 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1800 | ||
b5072380 | 1801 | if (PageAnon(page)) { |
c14a6eb4 | 1802 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1803 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1804 | } else { | |
953c66c2 AK |
1805 | if (arch_needs_pgtable_deposit()) |
1806 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1807 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1808 | } |
616b8371 | 1809 | |
da146769 | 1810 | spin_unlock(ptl); |
616b8371 ZY |
1811 | if (flush_needed) |
1812 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1813 | } |
da146769 | 1814 | return 1; |
71e3aac0 AA |
1815 | } |
1816 | ||
1dd38b6c AK |
1817 | #ifndef pmd_move_must_withdraw |
1818 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1819 | spinlock_t *old_pmd_ptl, | |
1820 | struct vm_area_struct *vma) | |
1821 | { | |
1822 | /* | |
1823 | * With split pmd lock we also need to move preallocated | |
1824 | * PTE page table if new_pmd is on different PMD page table. | |
1825 | * | |
1826 | * We also don't deposit and withdraw tables for file pages. | |
1827 | */ | |
1828 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1829 | } | |
1830 | #endif | |
1831 | ||
ab6e3d09 NH |
1832 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1833 | { | |
1834 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1835 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1836 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1837 | else if (pmd_present(pmd)) | |
1838 | pmd = pmd_mksoft_dirty(pmd); | |
1839 | #endif | |
1840 | return pmd; | |
1841 | } | |
1842 | ||
bf8616d5 | 1843 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1844 | unsigned long new_addr, unsigned long old_end, |
eb66ae03 | 1845 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1846 | { |
bf929152 | 1847 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1848 | pmd_t pmd; |
37a1c49a | 1849 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1850 | bool force_flush = false; |
37a1c49a AA |
1851 | |
1852 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1853 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1854 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1855 | return false; |
37a1c49a AA |
1856 | |
1857 | /* | |
1858 | * The destination pmd shouldn't be established, free_pgtables() | |
1859 | * should have release it. | |
1860 | */ | |
1861 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1862 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1863 | return false; |
37a1c49a AA |
1864 | } |
1865 | ||
bf929152 KS |
1866 | /* |
1867 | * We don't have to worry about the ordering of src and dst | |
1868 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1869 | */ | |
b6ec57f4 KS |
1870 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1871 | if (old_ptl) { | |
bf929152 KS |
1872 | new_ptl = pmd_lockptr(mm, new_pmd); |
1873 | if (new_ptl != old_ptl) | |
1874 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1875 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1876 | if (pmd_present(pmd)) |
a2ce2666 | 1877 | force_flush = true; |
025c5b24 | 1878 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1879 | |
1dd38b6c | 1880 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1881 | pgtable_t pgtable; |
3592806c KS |
1882 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1883 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1884 | } |
ab6e3d09 NH |
1885 | pmd = move_soft_dirty_pmd(pmd); |
1886 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1887 | if (force_flush) |
1888 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1889 | if (new_ptl != old_ptl) |
1890 | spin_unlock(new_ptl); | |
bf929152 | 1891 | spin_unlock(old_ptl); |
4b471e88 | 1892 | return true; |
37a1c49a | 1893 | } |
4b471e88 | 1894 | return false; |
37a1c49a AA |
1895 | } |
1896 | ||
f123d74a MG |
1897 | /* |
1898 | * Returns | |
1899 | * - 0 if PMD could not be locked | |
1900 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1901 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1902 | */ | |
cd7548ab | 1903 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1904 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1905 | { |
1906 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1907 | spinlock_t *ptl; |
0a85e51d KS |
1908 | pmd_t entry; |
1909 | bool preserve_write; | |
1910 | int ret; | |
cd7548ab | 1911 | |
b6ec57f4 | 1912 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1913 | if (!ptl) |
1914 | return 0; | |
e944fd67 | 1915 | |
0a85e51d KS |
1916 | preserve_write = prot_numa && pmd_write(*pmd); |
1917 | ret = 1; | |
e944fd67 | 1918 | |
84c3fc4e ZY |
1919 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1920 | if (is_swap_pmd(*pmd)) { | |
1921 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1922 | ||
1923 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1924 | if (is_write_migration_entry(entry)) { | |
1925 | pmd_t newpmd; | |
1926 | /* | |
1927 | * A protection check is difficult so | |
1928 | * just be safe and disable write | |
1929 | */ | |
1930 | make_migration_entry_read(&entry); | |
1931 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1932 | if (pmd_swp_soft_dirty(*pmd)) |
1933 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1934 | set_pmd_at(mm, addr, pmd, newpmd); |
1935 | } | |
1936 | goto unlock; | |
1937 | } | |
1938 | #endif | |
1939 | ||
0a85e51d KS |
1940 | /* |
1941 | * Avoid trapping faults against the zero page. The read-only | |
1942 | * data is likely to be read-cached on the local CPU and | |
1943 | * local/remote hits to the zero page are not interesting. | |
1944 | */ | |
1945 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1946 | goto unlock; | |
025c5b24 | 1947 | |
0a85e51d KS |
1948 | if (prot_numa && pmd_protnone(*pmd)) |
1949 | goto unlock; | |
1950 | ||
ced10803 KS |
1951 | /* |
1952 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1953 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1954 | * which is also under down_read(mmap_sem): | |
1955 | * | |
1956 | * CPU0: CPU1: | |
1957 | * change_huge_pmd(prot_numa=1) | |
1958 | * pmdp_huge_get_and_clear_notify() | |
1959 | * madvise_dontneed() | |
1960 | * zap_pmd_range() | |
1961 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1962 | * // skip the pmd | |
1963 | * set_pmd_at(); | |
1964 | * // pmd is re-established | |
1965 | * | |
1966 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1967 | * which may break userspace. | |
1968 | * | |
1969 | * pmdp_invalidate() is required to make sure we don't miss | |
1970 | * dirty/young flags set by hardware. | |
1971 | */ | |
a3cf988f | 1972 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1973 | |
0a85e51d KS |
1974 | entry = pmd_modify(entry, newprot); |
1975 | if (preserve_write) | |
1976 | entry = pmd_mk_savedwrite(entry); | |
1977 | ret = HPAGE_PMD_NR; | |
1978 | set_pmd_at(mm, addr, pmd, entry); | |
1979 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1980 | unlock: | |
1981 | spin_unlock(ptl); | |
025c5b24 NH |
1982 | return ret; |
1983 | } | |
1984 | ||
1985 | /* | |
8f19b0c0 | 1986 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1987 | * |
8f19b0c0 HY |
1988 | * Note that if it returns page table lock pointer, this routine returns without |
1989 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1990 | */ |
b6ec57f4 | 1991 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1992 | { |
b6ec57f4 KS |
1993 | spinlock_t *ptl; |
1994 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1995 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1996 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1997 | return ptl; |
1998 | spin_unlock(ptl); | |
1999 | return NULL; | |
cd7548ab JW |
2000 | } |
2001 | ||
a00cc7d9 MW |
2002 | /* |
2003 | * Returns true if a given pud maps a thp, false otherwise. | |
2004 | * | |
2005 | * Note that if it returns true, this routine returns without unlocking page | |
2006 | * table lock. So callers must unlock it. | |
2007 | */ | |
2008 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
2009 | { | |
2010 | spinlock_t *ptl; | |
2011 | ||
2012 | ptl = pud_lock(vma->vm_mm, pud); | |
2013 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
2014 | return ptl; | |
2015 | spin_unlock(ptl); | |
2016 | return NULL; | |
2017 | } | |
2018 | ||
2019 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
2020 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
2021 | pud_t *pud, unsigned long addr) | |
2022 | { | |
a00cc7d9 MW |
2023 | spinlock_t *ptl; |
2024 | ||
2025 | ptl = __pud_trans_huge_lock(pud, vma); | |
2026 | if (!ptl) | |
2027 | return 0; | |
2028 | /* | |
2029 | * For architectures like ppc64 we look at deposited pgtable | |
2030 | * when calling pudp_huge_get_and_clear. So do the | |
2031 | * pgtable_trans_huge_withdraw after finishing pudp related | |
2032 | * operations. | |
2033 | */ | |
70516b93 | 2034 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 MW |
2035 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2036 | if (vma_is_dax(vma)) { | |
2037 | spin_unlock(ptl); | |
2038 | /* No zero page support yet */ | |
2039 | } else { | |
2040 | /* No support for anonymous PUD pages yet */ | |
2041 | BUG(); | |
2042 | } | |
2043 | return 1; | |
2044 | } | |
2045 | ||
2046 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2047 | unsigned long haddr) | |
2048 | { | |
2049 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2050 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2051 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2052 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2053 | ||
ce9311cf | 2054 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2055 | |
2056 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2057 | } | |
2058 | ||
2059 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2060 | unsigned long address) | |
2061 | { | |
2062 | spinlock_t *ptl; | |
ac46d4f3 | 2063 | struct mmu_notifier_range range; |
a00cc7d9 | 2064 | |
7269f999 | 2065 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2066 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2067 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2068 | mmu_notifier_invalidate_range_start(&range); | |
2069 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2070 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2071 | goto out; | |
ac46d4f3 | 2072 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2073 | |
2074 | out: | |
2075 | spin_unlock(ptl); | |
4645b9fe JG |
2076 | /* |
2077 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2078 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2079 | */ | |
ac46d4f3 | 2080 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2081 | } |
2082 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2083 | ||
eef1b3ba KS |
2084 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2085 | unsigned long haddr, pmd_t *pmd) | |
2086 | { | |
2087 | struct mm_struct *mm = vma->vm_mm; | |
2088 | pgtable_t pgtable; | |
2089 | pmd_t _pmd; | |
2090 | int i; | |
2091 | ||
0f10851e JG |
2092 | /* |
2093 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2094 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2095 | * replacing a zero pmd write protected page with a zero pte write | |
2096 | * protected page. | |
2097 | * | |
ad56b738 | 2098 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2099 | */ |
2100 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2101 | |
2102 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2103 | pmd_populate(mm, &_pmd, pgtable); | |
2104 | ||
2105 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2106 | pte_t *pte, entry; | |
2107 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2108 | entry = pte_mkspecial(entry); | |
2109 | pte = pte_offset_map(&_pmd, haddr); | |
2110 | VM_BUG_ON(!pte_none(*pte)); | |
2111 | set_pte_at(mm, haddr, pte, entry); | |
2112 | pte_unmap(pte); | |
2113 | } | |
2114 | smp_wmb(); /* make pte visible before pmd */ | |
2115 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2116 | } |
2117 | ||
2118 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2119 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2120 | { |
2121 | struct mm_struct *mm = vma->vm_mm; | |
2122 | struct page *page; | |
2123 | pgtable_t pgtable; | |
423ac9af | 2124 | pmd_t old_pmd, _pmd; |
a3cf988f | 2125 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2126 | unsigned long addr; |
eef1b3ba KS |
2127 | int i; |
2128 | ||
2129 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2130 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2131 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2132 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2133 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2134 | |
2135 | count_vm_event(THP_SPLIT_PMD); | |
2136 | ||
d21b9e57 KS |
2137 | if (!vma_is_anonymous(vma)) { |
2138 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2139 | /* |
2140 | * We are going to unmap this huge page. So | |
2141 | * just go ahead and zap it | |
2142 | */ | |
2143 | if (arch_needs_pgtable_deposit()) | |
2144 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2145 | if (vma_is_dax(vma)) |
2146 | return; | |
2147 | page = pmd_page(_pmd); | |
e1f1b157 HD |
2148 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2149 | set_page_dirty(page); | |
d21b9e57 KS |
2150 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2151 | SetPageReferenced(page); | |
2152 | page_remove_rmap(page, true); | |
2153 | put_page(page); | |
fadae295 | 2154 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba KS |
2155 | return; |
2156 | } else if (is_huge_zero_pmd(*pmd)) { | |
4645b9fe JG |
2157 | /* |
2158 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2159 | * mmu_notifier_invalidate_range() see comments below inside | |
2160 | * __split_huge_pmd() ? | |
2161 | * | |
2162 | * We are going from a zero huge page write protected to zero | |
2163 | * small page also write protected so it does not seems useful | |
2164 | * to invalidate secondary mmu at this time. | |
2165 | */ | |
eef1b3ba KS |
2166 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2167 | } | |
2168 | ||
423ac9af AK |
2169 | /* |
2170 | * Up to this point the pmd is present and huge and userland has the | |
2171 | * whole access to the hugepage during the split (which happens in | |
2172 | * place). If we overwrite the pmd with the not-huge version pointing | |
2173 | * to the pte here (which of course we could if all CPUs were bug | |
2174 | * free), userland could trigger a small page size TLB miss on the | |
2175 | * small sized TLB while the hugepage TLB entry is still established in | |
2176 | * the huge TLB. Some CPU doesn't like that. | |
2177 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2178 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2179 | * only safe if the permission and cache attributes of the two entries | |
2180 | * loaded in the two TLB is identical (which should be the case here). | |
2181 | * But it is generally safer to never allow small and huge TLB entries | |
2182 | * for the same virtual address to be loaded simultaneously. So instead | |
2183 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2184 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2185 | * must remain set at all times on the pmd until the split is complete | |
2186 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2187 | * non-huge version of the pmd entry with pmd_populate. | |
2188 | */ | |
2189 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2190 | ||
423ac9af | 2191 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2192 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2193 | swp_entry_t entry; |
2194 | ||
423ac9af | 2195 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e | 2196 | page = pfn_to_page(swp_offset(entry)); |
2e83ee1d PX |
2197 | write = is_write_migration_entry(entry); |
2198 | young = false; | |
2199 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
2200 | } else { | |
423ac9af | 2201 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2202 | if (pmd_dirty(old_pmd)) |
2203 | SetPageDirty(page); | |
2204 | write = pmd_write(old_pmd); | |
2205 | young = pmd_young(old_pmd); | |
2206 | soft_dirty = pmd_soft_dirty(old_pmd); | |
2207 | } | |
eef1b3ba | 2208 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2209 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2210 | |
423ac9af AK |
2211 | /* |
2212 | * Withdraw the table only after we mark the pmd entry invalid. | |
2213 | * This's critical for some architectures (Power). | |
2214 | */ | |
eef1b3ba KS |
2215 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2216 | pmd_populate(mm, &_pmd, pgtable); | |
2217 | ||
2ac015e2 | 2218 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2219 | pte_t entry, *pte; |
2220 | /* | |
2221 | * Note that NUMA hinting access restrictions are not | |
2222 | * transferred to avoid any possibility of altering | |
2223 | * permissions across VMAs. | |
2224 | */ | |
84c3fc4e | 2225 | if (freeze || pmd_migration) { |
ba988280 KS |
2226 | swp_entry_t swp_entry; |
2227 | swp_entry = make_migration_entry(page + i, write); | |
2228 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2229 | if (soft_dirty) |
2230 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2231 | } else { |
6d2329f8 | 2232 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2233 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2234 | if (!write) |
2235 | entry = pte_wrprotect(entry); | |
2236 | if (!young) | |
2237 | entry = pte_mkold(entry); | |
804dd150 AA |
2238 | if (soft_dirty) |
2239 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2240 | } |
2ac015e2 | 2241 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2242 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2243 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2244 | atomic_inc(&page[i]._mapcount); |
2245 | pte_unmap(pte); | |
2246 | } | |
2247 | ||
2248 | /* | |
2249 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2250 | * false-negative page_mapped(). | |
2251 | */ | |
2252 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2253 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2254 | atomic_inc(&page[i]._mapcount); | |
2255 | } | |
2256 | ||
2257 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2258 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2259 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2260 | if (TestClearPageDoubleMap(page)) { |
2261 | /* No need in mapcount reference anymore */ | |
2262 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2263 | atomic_dec(&page[i]._mapcount); | |
2264 | } | |
2265 | } | |
2266 | ||
2267 | smp_wmb(); /* make pte visible before pmd */ | |
2268 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2269 | |
2270 | if (freeze) { | |
2ac015e2 | 2271 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2272 | page_remove_rmap(page + i, false); |
2273 | put_page(page + i); | |
2274 | } | |
2275 | } | |
eef1b3ba KS |
2276 | } |
2277 | ||
2278 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2279 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2280 | { |
2281 | spinlock_t *ptl; | |
ac46d4f3 | 2282 | struct mmu_notifier_range range; |
eef1b3ba | 2283 | |
7269f999 | 2284 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2285 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2286 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2287 | mmu_notifier_invalidate_range_start(&range); | |
2288 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2289 | |
2290 | /* | |
2291 | * If caller asks to setup a migration entries, we need a page to check | |
2292 | * pmd against. Otherwise we can end up replacing wrong page. | |
2293 | */ | |
2294 | VM_BUG_ON(freeze && !page); | |
2295 | if (page && page != pmd_page(*pmd)) | |
2296 | goto out; | |
2297 | ||
5c7fb56e | 2298 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2299 | page = pmd_page(*pmd); |
5c7fb56e | 2300 | if (PageMlocked(page)) |
5f737714 | 2301 | clear_page_mlock(page); |
84c3fc4e | 2302 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2303 | goto out; |
ac46d4f3 | 2304 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2305 | out: |
eef1b3ba | 2306 | spin_unlock(ptl); |
4645b9fe JG |
2307 | /* |
2308 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2309 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2310 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2311 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2312 | * fault will trigger a flush_notify before pointing to a new page | |
2313 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2314 | * page in the meantime) | |
2315 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2316 | * to invalidate secondary tlb entry they are all still valid. | |
2317 | * any further changes to individual pte will notify. So no need | |
2318 | * to call mmu_notifier->invalidate_range() | |
2319 | */ | |
ac46d4f3 | 2320 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2321 | } |
2322 | ||
fec89c10 KS |
2323 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2324 | bool freeze, struct page *page) | |
94fcc585 | 2325 | { |
f72e7dcd | 2326 | pgd_t *pgd; |
c2febafc | 2327 | p4d_t *p4d; |
f72e7dcd | 2328 | pud_t *pud; |
94fcc585 AA |
2329 | pmd_t *pmd; |
2330 | ||
78ddc534 | 2331 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2332 | if (!pgd_present(*pgd)) |
2333 | return; | |
2334 | ||
c2febafc KS |
2335 | p4d = p4d_offset(pgd, address); |
2336 | if (!p4d_present(*p4d)) | |
2337 | return; | |
2338 | ||
2339 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2340 | if (!pud_present(*pud)) |
2341 | return; | |
2342 | ||
2343 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2344 | |
33f4751e | 2345 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2346 | } |
2347 | ||
e1b9996b | 2348 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2349 | unsigned long start, |
2350 | unsigned long end, | |
2351 | long adjust_next) | |
2352 | { | |
2353 | /* | |
2354 | * If the new start address isn't hpage aligned and it could | |
2355 | * previously contain an hugepage: check if we need to split | |
2356 | * an huge pmd. | |
2357 | */ | |
2358 | if (start & ~HPAGE_PMD_MASK && | |
2359 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2360 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2361 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2362 | |
2363 | /* | |
2364 | * If the new end address isn't hpage aligned and it could | |
2365 | * previously contain an hugepage: check if we need to split | |
2366 | * an huge pmd. | |
2367 | */ | |
2368 | if (end & ~HPAGE_PMD_MASK && | |
2369 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2370 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2371 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2372 | |
2373 | /* | |
2374 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2375 | * vm_next->vm_start isn't page aligned and it could previously | |
2376 | * contain an hugepage: check if we need to split an huge pmd. | |
2377 | */ | |
2378 | if (adjust_next > 0) { | |
2379 | struct vm_area_struct *next = vma->vm_next; | |
2380 | unsigned long nstart = next->vm_start; | |
2381 | nstart += adjust_next << PAGE_SHIFT; | |
2382 | if (nstart & ~HPAGE_PMD_MASK && | |
2383 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2384 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2385 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2386 | } |
2387 | } | |
e9b61f19 | 2388 | |
906f9cdf | 2389 | static void unmap_page(struct page *page) |
e9b61f19 | 2390 | { |
baa355fd | 2391 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2392 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2393 | bool unmap_success; |
e9b61f19 KS |
2394 | |
2395 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2396 | ||
baa355fd | 2397 | if (PageAnon(page)) |
b5ff8161 | 2398 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2399 | |
666e5a40 MK |
2400 | unmap_success = try_to_unmap(page, ttu_flags); |
2401 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2402 | } |
2403 | ||
906f9cdf | 2404 | static void remap_page(struct page *page) |
e9b61f19 | 2405 | { |
fec89c10 | 2406 | int i; |
ace71a19 KS |
2407 | if (PageTransHuge(page)) { |
2408 | remove_migration_ptes(page, page, true); | |
2409 | } else { | |
2410 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2411 | remove_migration_ptes(page + i, page + i, true); | |
2412 | } | |
e9b61f19 KS |
2413 | } |
2414 | ||
8df651c7 | 2415 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2416 | struct lruvec *lruvec, struct list_head *list) |
2417 | { | |
e9b61f19 KS |
2418 | struct page *page_tail = head + tail; |
2419 | ||
8df651c7 | 2420 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2421 | |
2422 | /* | |
605ca5ed KK |
2423 | * Clone page flags before unfreezing refcount. |
2424 | * | |
2425 | * After successful get_page_unless_zero() might follow flags change, | |
2426 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2427 | */ |
e9b61f19 KS |
2428 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2429 | page_tail->flags |= (head->flags & | |
2430 | ((1L << PG_referenced) | | |
2431 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2432 | (1L << PG_swapcache) | |
e9b61f19 KS |
2433 | (1L << PG_mlocked) | |
2434 | (1L << PG_uptodate) | | |
2435 | (1L << PG_active) | | |
1899ad18 | 2436 | (1L << PG_workingset) | |
e9b61f19 | 2437 | (1L << PG_locked) | |
b8d3c4c3 MK |
2438 | (1L << PG_unevictable) | |
2439 | (1L << PG_dirty))); | |
e9b61f19 | 2440 | |
173d9d9f HD |
2441 | /* ->mapping in first tail page is compound_mapcount */ |
2442 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2443 | page_tail); | |
2444 | page_tail->mapping = head->mapping; | |
2445 | page_tail->index = head->index + tail; | |
2446 | ||
605ca5ed | 2447 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2448 | smp_wmb(); |
2449 | ||
605ca5ed KK |
2450 | /* |
2451 | * Clear PageTail before unfreezing page refcount. | |
2452 | * | |
2453 | * After successful get_page_unless_zero() might follow put_page() | |
2454 | * which needs correct compound_head(). | |
2455 | */ | |
e9b61f19 KS |
2456 | clear_compound_head(page_tail); |
2457 | ||
605ca5ed KK |
2458 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2459 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2460 | PageSwapCache(head))); | |
2461 | ||
e9b61f19 KS |
2462 | if (page_is_young(head)) |
2463 | set_page_young(page_tail); | |
2464 | if (page_is_idle(head)) | |
2465 | set_page_idle(page_tail); | |
2466 | ||
e9b61f19 | 2467 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2468 | |
2469 | /* | |
2470 | * always add to the tail because some iterators expect new | |
2471 | * pages to show after the currently processed elements - e.g. | |
2472 | * migrate_pages | |
2473 | */ | |
e9b61f19 | 2474 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2475 | } |
2476 | ||
baa355fd | 2477 | static void __split_huge_page(struct page *page, struct list_head *list, |
006d3ff2 | 2478 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2479 | { |
2480 | struct page *head = compound_head(page); | |
f4b7e272 | 2481 | pg_data_t *pgdat = page_pgdat(head); |
e9b61f19 | 2482 | struct lruvec *lruvec; |
8df651c7 | 2483 | int i; |
e9b61f19 | 2484 | |
f4b7e272 | 2485 | lruvec = mem_cgroup_page_lruvec(head, pgdat); |
e9b61f19 KS |
2486 | |
2487 | /* complete memcg works before add pages to LRU */ | |
2488 | mem_cgroup_split_huge_fixup(head); | |
2489 | ||
baa355fd | 2490 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2491 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2492 | /* Some pages can be beyond i_size: drop them from page cache */ |
2493 | if (head[i].index >= end) { | |
2d077d4b | 2494 | ClearPageDirty(head + i); |
baa355fd | 2495 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2496 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2497 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd | 2498 | put_page(head + i); |
5fd4ca2d MW |
2499 | } else if (!PageAnon(page)) { |
2500 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2501 | head + i, 0); | |
baa355fd KS |
2502 | } |
2503 | } | |
e9b61f19 KS |
2504 | |
2505 | ClearPageCompound(head); | |
baa355fd KS |
2506 | /* See comment in __split_huge_page_tail() */ |
2507 | if (PageAnon(head)) { | |
aa5dc07f | 2508 | /* Additional pin to swap cache */ |
38d8b4e6 HY |
2509 | if (PageSwapCache(head)) |
2510 | page_ref_add(head, 2); | |
2511 | else | |
2512 | page_ref_inc(head); | |
baa355fd | 2513 | } else { |
aa5dc07f | 2514 | /* Additional pin to page cache */ |
baa355fd | 2515 | page_ref_add(head, 2); |
b93b0163 | 2516 | xa_unlock(&head->mapping->i_pages); |
baa355fd KS |
2517 | } |
2518 | ||
f4b7e272 | 2519 | spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
e9b61f19 | 2520 | |
906f9cdf | 2521 | remap_page(head); |
e9b61f19 KS |
2522 | |
2523 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2524 | struct page *subpage = head + i; | |
2525 | if (subpage == page) | |
2526 | continue; | |
2527 | unlock_page(subpage); | |
2528 | ||
2529 | /* | |
2530 | * Subpages may be freed if there wasn't any mapping | |
2531 | * like if add_to_swap() is running on a lru page that | |
2532 | * had its mapping zapped. And freeing these pages | |
2533 | * requires taking the lru_lock so we do the put_page | |
2534 | * of the tail pages after the split is complete. | |
2535 | */ | |
2536 | put_page(subpage); | |
2537 | } | |
2538 | } | |
2539 | ||
b20ce5e0 KS |
2540 | int total_mapcount(struct page *page) |
2541 | { | |
dd78fedd | 2542 | int i, compound, ret; |
b20ce5e0 KS |
2543 | |
2544 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2545 | ||
2546 | if (likely(!PageCompound(page))) | |
2547 | return atomic_read(&page->_mapcount) + 1; | |
2548 | ||
dd78fedd | 2549 | compound = compound_mapcount(page); |
b20ce5e0 | 2550 | if (PageHuge(page)) |
dd78fedd KS |
2551 | return compound; |
2552 | ret = compound; | |
b20ce5e0 KS |
2553 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2554 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2555 | /* File pages has compound_mapcount included in _mapcount */ |
2556 | if (!PageAnon(page)) | |
2557 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2558 | if (PageDoubleMap(page)) |
2559 | ret -= HPAGE_PMD_NR; | |
2560 | return ret; | |
2561 | } | |
2562 | ||
6d0a07ed AA |
2563 | /* |
2564 | * This calculates accurately how many mappings a transparent hugepage | |
2565 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2566 | * accuracy is primarily needed to know if copy-on-write faults can | |
2567 | * reuse the page and change the mapping to read-write instead of | |
2568 | * copying them. At the same time this returns the total_mapcount too. | |
2569 | * | |
2570 | * The function returns the highest mapcount any one of the subpages | |
2571 | * has. If the return value is one, even if different processes are | |
2572 | * mapping different subpages of the transparent hugepage, they can | |
2573 | * all reuse it, because each process is reusing a different subpage. | |
2574 | * | |
2575 | * The total_mapcount is instead counting all virtual mappings of the | |
2576 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2577 | * caller all mappings belong to the same "mm" and in turn the | |
2578 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2579 | * local one as no other process may be mapping any of the subpages. | |
2580 | * | |
2581 | * It would be more accurate to replace page_mapcount() with | |
2582 | * page_trans_huge_mapcount(), however we only use | |
2583 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2584 | * need full accuracy to avoid breaking page pinning, because | |
2585 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2586 | */ | |
2587 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2588 | { | |
2589 | int i, ret, _total_mapcount, mapcount; | |
2590 | ||
2591 | /* hugetlbfs shouldn't call it */ | |
2592 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2593 | ||
2594 | if (likely(!PageTransCompound(page))) { | |
2595 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2596 | if (total_mapcount) | |
2597 | *total_mapcount = mapcount; | |
2598 | return mapcount; | |
2599 | } | |
2600 | ||
2601 | page = compound_head(page); | |
2602 | ||
2603 | _total_mapcount = ret = 0; | |
2604 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2605 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2606 | ret = max(ret, mapcount); | |
2607 | _total_mapcount += mapcount; | |
2608 | } | |
2609 | if (PageDoubleMap(page)) { | |
2610 | ret -= 1; | |
2611 | _total_mapcount -= HPAGE_PMD_NR; | |
2612 | } | |
2613 | mapcount = compound_mapcount(page); | |
2614 | ret += mapcount; | |
2615 | _total_mapcount += mapcount; | |
2616 | if (total_mapcount) | |
2617 | *total_mapcount = _total_mapcount; | |
2618 | return ret; | |
2619 | } | |
2620 | ||
b8f593cd HY |
2621 | /* Racy check whether the huge page can be split */ |
2622 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2623 | { | |
2624 | int extra_pins; | |
2625 | ||
aa5dc07f | 2626 | /* Additional pins from page cache */ |
b8f593cd HY |
2627 | if (PageAnon(page)) |
2628 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2629 | else | |
2630 | extra_pins = HPAGE_PMD_NR; | |
2631 | if (pextra_pins) | |
2632 | *pextra_pins = extra_pins; | |
2633 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2634 | } | |
2635 | ||
e9b61f19 KS |
2636 | /* |
2637 | * This function splits huge page into normal pages. @page can point to any | |
2638 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2639 | * | |
2640 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2641 | * The huge page must be locked. | |
2642 | * | |
2643 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2644 | * | |
2645 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2646 | * the hugepage. | |
2647 | * | |
2648 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2649 | * they are not mapped. | |
2650 | * | |
2651 | * Returns 0 if the hugepage is split successfully. | |
2652 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2653 | * us. | |
2654 | */ | |
2655 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2656 | { | |
2657 | struct page *head = compound_head(page); | |
a3d0a918 | 2658 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2659 | struct anon_vma *anon_vma = NULL; |
2660 | struct address_space *mapping = NULL; | |
2661 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2662 | bool mlocked; |
0b9b6fff | 2663 | unsigned long flags; |
006d3ff2 | 2664 | pgoff_t end; |
e9b61f19 KS |
2665 | |
2666 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2667 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2668 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2669 | ||
59807685 HY |
2670 | if (PageWriteback(page)) |
2671 | return -EBUSY; | |
2672 | ||
baa355fd KS |
2673 | if (PageAnon(head)) { |
2674 | /* | |
2675 | * The caller does not necessarily hold an mmap_sem that would | |
2676 | * prevent the anon_vma disappearing so we first we take a | |
2677 | * reference to it and then lock the anon_vma for write. This | |
2678 | * is similar to page_lock_anon_vma_read except the write lock | |
2679 | * is taken to serialise against parallel split or collapse | |
2680 | * operations. | |
2681 | */ | |
2682 | anon_vma = page_get_anon_vma(head); | |
2683 | if (!anon_vma) { | |
2684 | ret = -EBUSY; | |
2685 | goto out; | |
2686 | } | |
006d3ff2 | 2687 | end = -1; |
baa355fd KS |
2688 | mapping = NULL; |
2689 | anon_vma_lock_write(anon_vma); | |
2690 | } else { | |
2691 | mapping = head->mapping; | |
2692 | ||
2693 | /* Truncated ? */ | |
2694 | if (!mapping) { | |
2695 | ret = -EBUSY; | |
2696 | goto out; | |
2697 | } | |
2698 | ||
baa355fd KS |
2699 | anon_vma = NULL; |
2700 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2701 | |
2702 | /* | |
2703 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2704 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2705 | * which cannot be nested inside the page tree lock. So note | |
2706 | * end now: i_size itself may be changed at any moment, but | |
2707 | * head page lock is good enough to serialize the trimming. | |
2708 | */ | |
2709 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2710 | } |
e9b61f19 KS |
2711 | |
2712 | /* | |
906f9cdf | 2713 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2714 | * split PMDs |
2715 | */ | |
b8f593cd | 2716 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2717 | ret = -EBUSY; |
2718 | goto out_unlock; | |
2719 | } | |
2720 | ||
d9654322 | 2721 | mlocked = PageMlocked(page); |
906f9cdf | 2722 | unmap_page(head); |
e9b61f19 KS |
2723 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2724 | ||
d9654322 KS |
2725 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2726 | if (mlocked) | |
2727 | lru_add_drain(); | |
2728 | ||
baa355fd | 2729 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
f4b7e272 | 2730 | spin_lock_irqsave(&pgdata->lru_lock, flags); |
baa355fd KS |
2731 | |
2732 | if (mapping) { | |
aa5dc07f | 2733 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2734 | |
baa355fd | 2735 | /* |
aa5dc07f | 2736 | * Check if the head page is present in page cache. |
baa355fd KS |
2737 | * We assume all tail are present too, if head is there. |
2738 | */ | |
aa5dc07f MW |
2739 | xa_lock(&mapping->i_pages); |
2740 | if (xas_load(&xas) != head) | |
baa355fd KS |
2741 | goto fail; |
2742 | } | |
2743 | ||
0139aa7b | 2744 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2745 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2746 | count = page_count(head); |
2747 | mapcount = total_mapcount(head); | |
baa355fd | 2748 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2749 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2750 | pgdata->split_queue_len--; |
9a982250 KS |
2751 | list_del(page_deferred_list(head)); |
2752 | } | |
65c45377 | 2753 | if (mapping) |
11fb9989 | 2754 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd | 2755 | spin_unlock(&pgdata->split_queue_lock); |
006d3ff2 | 2756 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2757 | if (PageSwapCache(head)) { |
2758 | swp_entry_t entry = { .val = page_private(head) }; | |
2759 | ||
2760 | ret = split_swap_cluster(entry); | |
2761 | } else | |
2762 | ret = 0; | |
e9b61f19 | 2763 | } else { |
baa355fd KS |
2764 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2765 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2766 | mapcount, count); | |
2767 | if (PageTail(page)) | |
2768 | dump_page(head, NULL); | |
2769 | dump_page(page, "total_mapcount(head) > 0"); | |
2770 | BUG(); | |
2771 | } | |
2772 | spin_unlock(&pgdata->split_queue_lock); | |
2773 | fail: if (mapping) | |
b93b0163 | 2774 | xa_unlock(&mapping->i_pages); |
f4b7e272 | 2775 | spin_unlock_irqrestore(&pgdata->lru_lock, flags); |
906f9cdf | 2776 | remap_page(head); |
e9b61f19 KS |
2777 | ret = -EBUSY; |
2778 | } | |
2779 | ||
2780 | out_unlock: | |
baa355fd KS |
2781 | if (anon_vma) { |
2782 | anon_vma_unlock_write(anon_vma); | |
2783 | put_anon_vma(anon_vma); | |
2784 | } | |
2785 | if (mapping) | |
2786 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2787 | out: |
2788 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2789 | return ret; | |
2790 | } | |
9a982250 KS |
2791 | |
2792 | void free_transhuge_page(struct page *page) | |
2793 | { | |
a3d0a918 | 2794 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2795 | unsigned long flags; |
2796 | ||
a3d0a918 | 2797 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2798 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2799 | pgdata->split_queue_len--; |
9a982250 KS |
2800 | list_del(page_deferred_list(page)); |
2801 | } | |
a3d0a918 | 2802 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2803 | free_compound_page(page); |
2804 | } | |
2805 | ||
2806 | void deferred_split_huge_page(struct page *page) | |
2807 | { | |
a3d0a918 | 2808 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2809 | unsigned long flags; |
2810 | ||
2811 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2812 | ||
a3d0a918 | 2813 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2814 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2815 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2816 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2817 | pgdata->split_queue_len++; | |
9a982250 | 2818 | } |
a3d0a918 | 2819 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2820 | } |
2821 | ||
2822 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2823 | struct shrink_control *sc) | |
2824 | { | |
a3d0a918 | 2825 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
6aa7de05 | 2826 | return READ_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2827 | } |
2828 | ||
2829 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2830 | struct shrink_control *sc) | |
2831 | { | |
a3d0a918 | 2832 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2833 | unsigned long flags; |
2834 | LIST_HEAD(list), *pos, *next; | |
2835 | struct page *page; | |
2836 | int split = 0; | |
2837 | ||
a3d0a918 | 2838 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2839 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2840 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2841 | page = list_entry((void *)pos, struct page, mapping); |
2842 | page = compound_head(page); | |
e3ae1953 KS |
2843 | if (get_page_unless_zero(page)) { |
2844 | list_move(page_deferred_list(page), &list); | |
2845 | } else { | |
2846 | /* We lost race with put_compound_page() */ | |
9a982250 | 2847 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2848 | pgdata->split_queue_len--; |
9a982250 | 2849 | } |
e3ae1953 KS |
2850 | if (!--sc->nr_to_scan) |
2851 | break; | |
9a982250 | 2852 | } |
a3d0a918 | 2853 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2854 | |
2855 | list_for_each_safe(pos, next, &list) { | |
2856 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2857 | if (!trylock_page(page)) |
2858 | goto next; | |
9a982250 KS |
2859 | /* split_huge_page() removes page from list on success */ |
2860 | if (!split_huge_page(page)) | |
2861 | split++; | |
2862 | unlock_page(page); | |
fa41b900 | 2863 | next: |
9a982250 KS |
2864 | put_page(page); |
2865 | } | |
2866 | ||
a3d0a918 KS |
2867 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2868 | list_splice_tail(&list, &pgdata->split_queue); | |
2869 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2870 | |
cb8d68ec KS |
2871 | /* |
2872 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2873 | * This can happen if pages were freed under us. | |
2874 | */ | |
2875 | if (!split && list_empty(&pgdata->split_queue)) | |
2876 | return SHRINK_STOP; | |
2877 | return split; | |
9a982250 KS |
2878 | } |
2879 | ||
2880 | static struct shrinker deferred_split_shrinker = { | |
2881 | .count_objects = deferred_split_count, | |
2882 | .scan_objects = deferred_split_scan, | |
2883 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2884 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2885 | }; |
49071d43 KS |
2886 | |
2887 | #ifdef CONFIG_DEBUG_FS | |
2888 | static int split_huge_pages_set(void *data, u64 val) | |
2889 | { | |
2890 | struct zone *zone; | |
2891 | struct page *page; | |
2892 | unsigned long pfn, max_zone_pfn; | |
2893 | unsigned long total = 0, split = 0; | |
2894 | ||
2895 | if (val != 1) | |
2896 | return -EINVAL; | |
2897 | ||
2898 | for_each_populated_zone(zone) { | |
2899 | max_zone_pfn = zone_end_pfn(zone); | |
2900 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2901 | if (!pfn_valid(pfn)) | |
2902 | continue; | |
2903 | ||
2904 | page = pfn_to_page(pfn); | |
2905 | if (!get_page_unless_zero(page)) | |
2906 | continue; | |
2907 | ||
2908 | if (zone != page_zone(page)) | |
2909 | goto next; | |
2910 | ||
baa355fd | 2911 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2912 | goto next; |
2913 | ||
2914 | total++; | |
2915 | lock_page(page); | |
2916 | if (!split_huge_page(page)) | |
2917 | split++; | |
2918 | unlock_page(page); | |
2919 | next: | |
2920 | put_page(page); | |
2921 | } | |
2922 | } | |
2923 | ||
145bdaa1 | 2924 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2925 | |
2926 | return 0; | |
2927 | } | |
2928 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2929 | "%llu\n"); | |
2930 | ||
2931 | static int __init split_huge_pages_debugfs(void) | |
2932 | { | |
d9f7979c GKH |
2933 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
2934 | &split_huge_pages_fops); | |
49071d43 KS |
2935 | return 0; |
2936 | } | |
2937 | late_initcall(split_huge_pages_debugfs); | |
2938 | #endif | |
616b8371 ZY |
2939 | |
2940 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2941 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2942 | struct page *page) | |
2943 | { | |
2944 | struct vm_area_struct *vma = pvmw->vma; | |
2945 | struct mm_struct *mm = vma->vm_mm; | |
2946 | unsigned long address = pvmw->address; | |
2947 | pmd_t pmdval; | |
2948 | swp_entry_t entry; | |
ab6e3d09 | 2949 | pmd_t pmdswp; |
616b8371 ZY |
2950 | |
2951 | if (!(pvmw->pmd && !pvmw->pte)) | |
2952 | return; | |
2953 | ||
616b8371 ZY |
2954 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
2955 | pmdval = *pvmw->pmd; | |
2956 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2957 | if (pmd_dirty(pmdval)) | |
2958 | set_page_dirty(page); | |
2959 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2960 | pmdswp = swp_entry_to_pmd(entry); |
2961 | if (pmd_soft_dirty(pmdval)) | |
2962 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2963 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2964 | page_remove_rmap(page, true); |
2965 | put_page(page); | |
616b8371 ZY |
2966 | } |
2967 | ||
2968 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2969 | { | |
2970 | struct vm_area_struct *vma = pvmw->vma; | |
2971 | struct mm_struct *mm = vma->vm_mm; | |
2972 | unsigned long address = pvmw->address; | |
2973 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2974 | pmd_t pmde; | |
2975 | swp_entry_t entry; | |
2976 | ||
2977 | if (!(pvmw->pmd && !pvmw->pte)) | |
2978 | return; | |
2979 | ||
2980 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2981 | get_page(new); | |
2982 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2983 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2984 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 2985 | if (is_write_migration_entry(entry)) |
f55e1014 | 2986 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
2987 | |
2988 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
2989 | if (PageAnon(new)) |
2990 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2991 | else | |
2992 | page_add_file_rmap(new, true); | |
616b8371 | 2993 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 2994 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
2995 | mlock_vma_page(new); |
2996 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
2997 | } | |
2998 | #endif |