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Commit | Line | Data |
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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
ae3a8c1c AM |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | ||
71e3aac0 AA |
10 | #include <linux/mm.h> |
11 | #include <linux/sched.h> | |
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> |
97ae1749 | 33 | |
71e3aac0 AA |
34 | #include <asm/tlb.h> |
35 | #include <asm/pgalloc.h> | |
36 | #include "internal.h" | |
37 | ||
ba76149f | 38 | /* |
8bfa3f9a JW |
39 | * By default transparent hugepage support is disabled in order that avoid |
40 | * to risk increase the memory footprint of applications without a guaranteed | |
41 | * benefit. When transparent hugepage support is enabled, is for all mappings, | |
42 | * and khugepaged scans all mappings. | |
43 | * Defrag is invoked by khugepaged hugepage allocations and by page faults | |
44 | * for all hugepage allocations. | |
ba76149f | 45 | */ |
71e3aac0 | 46 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 47 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 48 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
49 | #endif |
50 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
51 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
52 | #endif | |
444eb2a4 | 53 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
54 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
55 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 56 | |
9a982250 | 57 | static struct shrinker deferred_split_shrinker; |
f000565a | 58 | |
97ae1749 | 59 | static atomic_t huge_zero_refcount; |
56873f43 | 60 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 61 | |
6fcb52a5 | 62 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
63 | { |
64 | struct page *zero_page; | |
65 | retry: | |
66 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 67 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
68 | |
69 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 70 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
71 | if (!zero_page) { |
72 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 73 | return NULL; |
d8a8e1f0 KS |
74 | } |
75 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 76 | preempt_disable(); |
5918d10a | 77 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 78 | preempt_enable(); |
5ddacbe9 | 79 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
80 | goto retry; |
81 | } | |
82 | ||
83 | /* We take additional reference here. It will be put back by shrinker */ | |
84 | atomic_set(&huge_zero_refcount, 2); | |
85 | preempt_enable(); | |
4db0c3c2 | 86 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
87 | } |
88 | ||
6fcb52a5 | 89 | static void put_huge_zero_page(void) |
4a6c1297 | 90 | { |
97ae1749 KS |
91 | /* |
92 | * Counter should never go to zero here. Only shrinker can put | |
93 | * last reference. | |
94 | */ | |
95 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
96 | } |
97 | ||
6fcb52a5 AL |
98 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
99 | { | |
100 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
101 | return READ_ONCE(huge_zero_page); | |
102 | ||
103 | if (!get_huge_zero_page()) | |
104 | return NULL; | |
105 | ||
106 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
107 | put_huge_zero_page(); | |
108 | ||
109 | return READ_ONCE(huge_zero_page); | |
110 | } | |
111 | ||
112 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
113 | { | |
114 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
115 | put_huge_zero_page(); | |
116 | } | |
117 | ||
48896466 GC |
118 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
119 | struct shrink_control *sc) | |
4a6c1297 | 120 | { |
48896466 GC |
121 | /* we can free zero page only if last reference remains */ |
122 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
123 | } | |
97ae1749 | 124 | |
48896466 GC |
125 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
126 | struct shrink_control *sc) | |
127 | { | |
97ae1749 | 128 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
129 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
130 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 131 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 132 | return HPAGE_PMD_NR; |
97ae1749 KS |
133 | } |
134 | ||
135 | return 0; | |
4a6c1297 KS |
136 | } |
137 | ||
97ae1749 | 138 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
139 | .count_objects = shrink_huge_zero_page_count, |
140 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
141 | .seeks = DEFAULT_SEEKS, |
142 | }; | |
143 | ||
71e3aac0 | 144 | #ifdef CONFIG_SYSFS |
ba76149f | 145 | |
444eb2a4 | 146 | static ssize_t triple_flag_store(struct kobject *kobj, |
71e3aac0 AA |
147 | struct kobj_attribute *attr, |
148 | const char *buf, size_t count, | |
149 | enum transparent_hugepage_flag enabled, | |
444eb2a4 | 150 | enum transparent_hugepage_flag deferred, |
71e3aac0 AA |
151 | enum transparent_hugepage_flag req_madv) |
152 | { | |
444eb2a4 MG |
153 | if (!memcmp("defer", buf, |
154 | min(sizeof("defer")-1, count))) { | |
155 | if (enabled == deferred) | |
156 | return -EINVAL; | |
157 | clear_bit(enabled, &transparent_hugepage_flags); | |
158 | clear_bit(req_madv, &transparent_hugepage_flags); | |
159 | set_bit(deferred, &transparent_hugepage_flags); | |
160 | } else if (!memcmp("always", buf, | |
71e3aac0 | 161 | min(sizeof("always")-1, count))) { |
444eb2a4 | 162 | clear_bit(deferred, &transparent_hugepage_flags); |
71e3aac0 | 163 | clear_bit(req_madv, &transparent_hugepage_flags); |
444eb2a4 | 164 | set_bit(enabled, &transparent_hugepage_flags); |
71e3aac0 AA |
165 | } else if (!memcmp("madvise", buf, |
166 | min(sizeof("madvise")-1, count))) { | |
167 | clear_bit(enabled, &transparent_hugepage_flags); | |
444eb2a4 | 168 | clear_bit(deferred, &transparent_hugepage_flags); |
71e3aac0 AA |
169 | set_bit(req_madv, &transparent_hugepage_flags); |
170 | } else if (!memcmp("never", buf, | |
171 | min(sizeof("never")-1, count))) { | |
172 | clear_bit(enabled, &transparent_hugepage_flags); | |
173 | clear_bit(req_madv, &transparent_hugepage_flags); | |
444eb2a4 | 174 | clear_bit(deferred, &transparent_hugepage_flags); |
71e3aac0 AA |
175 | } else |
176 | return -EINVAL; | |
177 | ||
178 | return count; | |
179 | } | |
180 | ||
181 | static ssize_t enabled_show(struct kobject *kobj, | |
182 | struct kobj_attribute *attr, char *buf) | |
183 | { | |
444eb2a4 MG |
184 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
185 | return sprintf(buf, "[always] madvise never\n"); | |
186 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
187 | return sprintf(buf, "always [madvise] never\n"); | |
188 | else | |
189 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 190 | } |
444eb2a4 | 191 | |
71e3aac0 AA |
192 | static ssize_t enabled_store(struct kobject *kobj, |
193 | struct kobj_attribute *attr, | |
194 | const char *buf, size_t count) | |
195 | { | |
ba76149f AA |
196 | ssize_t ret; |
197 | ||
444eb2a4 MG |
198 | ret = triple_flag_store(kobj, attr, buf, count, |
199 | TRANSPARENT_HUGEPAGE_FLAG, | |
ba76149f AA |
200 | TRANSPARENT_HUGEPAGE_FLAG, |
201 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
202 | ||
203 | if (ret > 0) { | |
b46e756f | 204 | int err = start_stop_khugepaged(); |
ba76149f AA |
205 | if (err) |
206 | ret = err; | |
207 | } | |
208 | ||
209 | return ret; | |
71e3aac0 AA |
210 | } |
211 | static struct kobj_attribute enabled_attr = | |
212 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
213 | ||
b46e756f | 214 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
215 | struct kobj_attribute *attr, char *buf, |
216 | enum transparent_hugepage_flag flag) | |
217 | { | |
e27e6151 BH |
218 | return sprintf(buf, "%d\n", |
219 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 220 | } |
e27e6151 | 221 | |
b46e756f | 222 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
223 | struct kobj_attribute *attr, |
224 | const char *buf, size_t count, | |
225 | enum transparent_hugepage_flag flag) | |
226 | { | |
e27e6151 BH |
227 | unsigned long value; |
228 | int ret; | |
229 | ||
230 | ret = kstrtoul(buf, 10, &value); | |
231 | if (ret < 0) | |
232 | return ret; | |
233 | if (value > 1) | |
234 | return -EINVAL; | |
235 | ||
236 | if (value) | |
71e3aac0 | 237 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 238 | else |
71e3aac0 | 239 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
240 | |
241 | return count; | |
242 | } | |
243 | ||
244 | /* | |
245 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
246 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
247 | * memory just to allocate one more hugepage. | |
248 | */ | |
249 | static ssize_t defrag_show(struct kobject *kobj, | |
250 | struct kobj_attribute *attr, char *buf) | |
251 | { | |
444eb2a4 MG |
252 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
253 | return sprintf(buf, "[always] defer madvise never\n"); | |
254 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) | |
255 | return sprintf(buf, "always [defer] madvise never\n"); | |
256 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
257 | return sprintf(buf, "always defer [madvise] never\n"); | |
258 | else | |
259 | return sprintf(buf, "always defer madvise [never]\n"); | |
260 | ||
71e3aac0 AA |
261 | } |
262 | static ssize_t defrag_store(struct kobject *kobj, | |
263 | struct kobj_attribute *attr, | |
264 | const char *buf, size_t count) | |
265 | { | |
444eb2a4 MG |
266 | return triple_flag_store(kobj, attr, buf, count, |
267 | TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
268 | TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
71e3aac0 AA |
269 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); |
270 | } | |
271 | static struct kobj_attribute defrag_attr = | |
272 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
273 | ||
79da5407 KS |
274 | static ssize_t use_zero_page_show(struct kobject *kobj, |
275 | struct kobj_attribute *attr, char *buf) | |
276 | { | |
b46e756f | 277 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
278 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
279 | } | |
280 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
281 | struct kobj_attribute *attr, const char *buf, size_t count) | |
282 | { | |
b46e756f | 283 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
284 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
285 | } | |
286 | static struct kobj_attribute use_zero_page_attr = | |
287 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
71e3aac0 AA |
288 | #ifdef CONFIG_DEBUG_VM |
289 | static ssize_t debug_cow_show(struct kobject *kobj, | |
290 | struct kobj_attribute *attr, char *buf) | |
291 | { | |
b46e756f | 292 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
293 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
294 | } | |
295 | static ssize_t debug_cow_store(struct kobject *kobj, | |
296 | struct kobj_attribute *attr, | |
297 | const char *buf, size_t count) | |
298 | { | |
b46e756f | 299 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
300 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
301 | } | |
302 | static struct kobj_attribute debug_cow_attr = | |
303 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
304 | #endif /* CONFIG_DEBUG_VM */ | |
305 | ||
306 | static struct attribute *hugepage_attr[] = { | |
307 | &enabled_attr.attr, | |
308 | &defrag_attr.attr, | |
79da5407 | 309 | &use_zero_page_attr.attr, |
e496cf3d | 310 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
311 | &shmem_enabled_attr.attr, |
312 | #endif | |
71e3aac0 AA |
313 | #ifdef CONFIG_DEBUG_VM |
314 | &debug_cow_attr.attr, | |
315 | #endif | |
316 | NULL, | |
317 | }; | |
318 | ||
319 | static struct attribute_group hugepage_attr_group = { | |
320 | .attrs = hugepage_attr, | |
ba76149f AA |
321 | }; |
322 | ||
569e5590 | 323 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 324 | { |
71e3aac0 AA |
325 | int err; |
326 | ||
569e5590 SL |
327 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
328 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 329 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 330 | return -ENOMEM; |
ba76149f AA |
331 | } |
332 | ||
569e5590 | 333 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 334 | if (err) { |
ae3a8c1c | 335 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 336 | goto delete_obj; |
ba76149f AA |
337 | } |
338 | ||
569e5590 | 339 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 340 | if (err) { |
ae3a8c1c | 341 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 342 | goto remove_hp_group; |
ba76149f | 343 | } |
569e5590 SL |
344 | |
345 | return 0; | |
346 | ||
347 | remove_hp_group: | |
348 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
349 | delete_obj: | |
350 | kobject_put(*hugepage_kobj); | |
351 | return err; | |
352 | } | |
353 | ||
354 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
355 | { | |
356 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
357 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
358 | kobject_put(hugepage_kobj); | |
359 | } | |
360 | #else | |
361 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
362 | { | |
363 | return 0; | |
364 | } | |
365 | ||
366 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
367 | { | |
368 | } | |
369 | #endif /* CONFIG_SYSFS */ | |
370 | ||
371 | static int __init hugepage_init(void) | |
372 | { | |
373 | int err; | |
374 | struct kobject *hugepage_kobj; | |
375 | ||
376 | if (!has_transparent_hugepage()) { | |
377 | transparent_hugepage_flags = 0; | |
378 | return -EINVAL; | |
379 | } | |
380 | ||
ff20c2e0 KS |
381 | /* |
382 | * hugepages can't be allocated by the buddy allocator | |
383 | */ | |
384 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
385 | /* | |
386 | * we use page->mapping and page->index in second tail page | |
387 | * as list_head: assuming THP order >= 2 | |
388 | */ | |
389 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
390 | ||
569e5590 SL |
391 | err = hugepage_init_sysfs(&hugepage_kobj); |
392 | if (err) | |
65ebb64f | 393 | goto err_sysfs; |
ba76149f | 394 | |
b46e756f | 395 | err = khugepaged_init(); |
ba76149f | 396 | if (err) |
65ebb64f | 397 | goto err_slab; |
ba76149f | 398 | |
65ebb64f KS |
399 | err = register_shrinker(&huge_zero_page_shrinker); |
400 | if (err) | |
401 | goto err_hzp_shrinker; | |
9a982250 KS |
402 | err = register_shrinker(&deferred_split_shrinker); |
403 | if (err) | |
404 | goto err_split_shrinker; | |
97ae1749 | 405 | |
97562cd2 RR |
406 | /* |
407 | * By default disable transparent hugepages on smaller systems, | |
408 | * where the extra memory used could hurt more than TLB overhead | |
409 | * is likely to save. The admin can still enable it through /sys. | |
410 | */ | |
79553da2 | 411 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 412 | transparent_hugepage_flags = 0; |
79553da2 KS |
413 | return 0; |
414 | } | |
97562cd2 | 415 | |
79553da2 | 416 | err = start_stop_khugepaged(); |
65ebb64f KS |
417 | if (err) |
418 | goto err_khugepaged; | |
ba76149f | 419 | |
569e5590 | 420 | return 0; |
65ebb64f | 421 | err_khugepaged: |
9a982250 KS |
422 | unregister_shrinker(&deferred_split_shrinker); |
423 | err_split_shrinker: | |
65ebb64f KS |
424 | unregister_shrinker(&huge_zero_page_shrinker); |
425 | err_hzp_shrinker: | |
b46e756f | 426 | khugepaged_destroy(); |
65ebb64f | 427 | err_slab: |
569e5590 | 428 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 429 | err_sysfs: |
ba76149f | 430 | return err; |
71e3aac0 | 431 | } |
a64fb3cd | 432 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
433 | |
434 | static int __init setup_transparent_hugepage(char *str) | |
435 | { | |
436 | int ret = 0; | |
437 | if (!str) | |
438 | goto out; | |
439 | if (!strcmp(str, "always")) { | |
440 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
441 | &transparent_hugepage_flags); | |
442 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
443 | &transparent_hugepage_flags); | |
444 | ret = 1; | |
445 | } else if (!strcmp(str, "madvise")) { | |
446 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
447 | &transparent_hugepage_flags); | |
448 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
449 | &transparent_hugepage_flags); | |
450 | ret = 1; | |
451 | } else if (!strcmp(str, "never")) { | |
452 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
453 | &transparent_hugepage_flags); | |
454 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
455 | &transparent_hugepage_flags); | |
456 | ret = 1; | |
457 | } | |
458 | out: | |
459 | if (!ret) | |
ae3a8c1c | 460 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
461 | return ret; |
462 | } | |
463 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
464 | ||
b32967ff | 465 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
466 | { |
467 | if (likely(vma->vm_flags & VM_WRITE)) | |
468 | pmd = pmd_mkwrite(pmd); | |
469 | return pmd; | |
470 | } | |
471 | ||
9a982250 KS |
472 | static inline struct list_head *page_deferred_list(struct page *page) |
473 | { | |
474 | /* | |
475 | * ->lru in the tail pages is occupied by compound_head. | |
476 | * Let's use ->mapping + ->index in the second tail page as list_head. | |
477 | */ | |
478 | return (struct list_head *)&page[2].mapping; | |
479 | } | |
480 | ||
481 | void prep_transhuge_page(struct page *page) | |
482 | { | |
483 | /* | |
484 | * we use page->mapping and page->indexlru in second tail page | |
485 | * as list_head: assuming THP order >= 2 | |
486 | */ | |
9a982250 KS |
487 | |
488 | INIT_LIST_HEAD(page_deferred_list(page)); | |
489 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
490 | } | |
491 | ||
74d2fad1 TK |
492 | unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
493 | loff_t off, unsigned long flags, unsigned long size) | |
494 | { | |
495 | unsigned long addr; | |
496 | loff_t off_end = off + len; | |
497 | loff_t off_align = round_up(off, size); | |
498 | unsigned long len_pad; | |
499 | ||
500 | if (off_end <= off_align || (off_end - off_align) < size) | |
501 | return 0; | |
502 | ||
503 | len_pad = len + size; | |
504 | if (len_pad < len || (off + len_pad) < off) | |
505 | return 0; | |
506 | ||
507 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
508 | off >> PAGE_SHIFT, flags); | |
509 | if (IS_ERR_VALUE(addr)) | |
510 | return 0; | |
511 | ||
512 | addr += (off - addr) & (size - 1); | |
513 | return addr; | |
514 | } | |
515 | ||
516 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
517 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
518 | { | |
519 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
520 | ||
521 | if (addr) | |
522 | goto out; | |
523 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
524 | goto out; | |
525 | ||
526 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
527 | if (addr) | |
528 | return addr; | |
529 | ||
530 | out: | |
531 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
532 | } | |
533 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
534 | ||
bae473a4 KS |
535 | static int __do_huge_pmd_anonymous_page(struct fault_env *fe, struct page *page, |
536 | gfp_t gfp) | |
71e3aac0 | 537 | { |
bae473a4 | 538 | struct vm_area_struct *vma = fe->vma; |
00501b53 | 539 | struct mem_cgroup *memcg; |
71e3aac0 | 540 | pgtable_t pgtable; |
bae473a4 | 541 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; |
71e3aac0 | 542 | |
309381fe | 543 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 544 | |
bae473a4 | 545 | if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
546 | put_page(page); |
547 | count_vm_event(THP_FAULT_FALLBACK); | |
548 | return VM_FAULT_FALLBACK; | |
549 | } | |
00501b53 | 550 | |
bae473a4 | 551 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
00501b53 | 552 | if (unlikely(!pgtable)) { |
f627c2f5 | 553 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 554 | put_page(page); |
71e3aac0 | 555 | return VM_FAULT_OOM; |
00501b53 | 556 | } |
71e3aac0 AA |
557 | |
558 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
52f37629 MK |
559 | /* |
560 | * The memory barrier inside __SetPageUptodate makes sure that | |
561 | * clear_huge_page writes become visible before the set_pmd_at() | |
562 | * write. | |
563 | */ | |
71e3aac0 AA |
564 | __SetPageUptodate(page); |
565 | ||
bae473a4 KS |
566 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); |
567 | if (unlikely(!pmd_none(*fe->pmd))) { | |
568 | spin_unlock(fe->ptl); | |
f627c2f5 | 569 | mem_cgroup_cancel_charge(page, memcg, true); |
71e3aac0 | 570 | put_page(page); |
bae473a4 | 571 | pte_free(vma->vm_mm, pgtable); |
71e3aac0 AA |
572 | } else { |
573 | pmd_t entry; | |
6b251fc9 AA |
574 | |
575 | /* Deliver the page fault to userland */ | |
576 | if (userfaultfd_missing(vma)) { | |
577 | int ret; | |
578 | ||
bae473a4 | 579 | spin_unlock(fe->ptl); |
f627c2f5 | 580 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 581 | put_page(page); |
bae473a4 KS |
582 | pte_free(vma->vm_mm, pgtable); |
583 | ret = handle_userfault(fe, VM_UFFD_MISSING); | |
6b251fc9 AA |
584 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
585 | return ret; | |
586 | } | |
587 | ||
3122359a KS |
588 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
589 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
d281ee61 | 590 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 591 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 592 | lru_cache_add_active_or_unevictable(page, vma); |
bae473a4 KS |
593 | pgtable_trans_huge_deposit(vma->vm_mm, fe->pmd, pgtable); |
594 | set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry); | |
595 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
596 | atomic_long_inc(&vma->vm_mm->nr_ptes); | |
597 | spin_unlock(fe->ptl); | |
6b251fc9 | 598 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 AA |
599 | } |
600 | ||
aa2e878e | 601 | return 0; |
71e3aac0 AA |
602 | } |
603 | ||
444eb2a4 | 604 | /* |
25160354 VB |
605 | * If THP defrag is set to always then directly reclaim/compact as necessary |
606 | * If set to defer then do only background reclaim/compact and defer to khugepaged | |
444eb2a4 | 607 | * If set to madvise and the VMA is flagged then directly reclaim/compact |
25160354 | 608 | * When direct reclaim/compact is allowed, don't retry except for flagged VMA's |
444eb2a4 MG |
609 | */ |
610 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) | |
611 | { | |
25160354 VB |
612 | bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
613 | ||
614 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
615 | &transparent_hugepage_flags) && vma_madvised) | |
616 | return GFP_TRANSHUGE; | |
617 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
618 | &transparent_hugepage_flags)) | |
619 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; | |
620 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
621 | &transparent_hugepage_flags)) | |
622 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
623 | ||
624 | return GFP_TRANSHUGE_LIGHT; | |
444eb2a4 MG |
625 | } |
626 | ||
c4088ebd | 627 | /* Caller must hold page table lock. */ |
d295e341 | 628 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 629 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 630 | struct page *zero_page) |
fc9fe822 KS |
631 | { |
632 | pmd_t entry; | |
7c414164 AM |
633 | if (!pmd_none(*pmd)) |
634 | return false; | |
5918d10a | 635 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 636 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
637 | if (pgtable) |
638 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 639 | set_pmd_at(mm, haddr, pmd, entry); |
e1f56c89 | 640 | atomic_long_inc(&mm->nr_ptes); |
7c414164 | 641 | return true; |
fc9fe822 KS |
642 | } |
643 | ||
bae473a4 | 644 | int do_huge_pmd_anonymous_page(struct fault_env *fe) |
71e3aac0 | 645 | { |
bae473a4 | 646 | struct vm_area_struct *vma = fe->vma; |
077fcf11 | 647 | gfp_t gfp; |
71e3aac0 | 648 | struct page *page; |
bae473a4 | 649 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; |
71e3aac0 | 650 | |
128ec037 | 651 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 652 | return VM_FAULT_FALLBACK; |
128ec037 KS |
653 | if (unlikely(anon_vma_prepare(vma))) |
654 | return VM_FAULT_OOM; | |
6d50e60c | 655 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 656 | return VM_FAULT_OOM; |
bae473a4 KS |
657 | if (!(fe->flags & FAULT_FLAG_WRITE) && |
658 | !mm_forbids_zeropage(vma->vm_mm) && | |
128ec037 KS |
659 | transparent_hugepage_use_zero_page()) { |
660 | pgtable_t pgtable; | |
661 | struct page *zero_page; | |
662 | bool set; | |
6b251fc9 | 663 | int ret; |
bae473a4 | 664 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
128ec037 | 665 | if (unlikely(!pgtable)) |
ba76149f | 666 | return VM_FAULT_OOM; |
6fcb52a5 | 667 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 668 | if (unlikely(!zero_page)) { |
bae473a4 | 669 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 670 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 671 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 672 | } |
bae473a4 | 673 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); |
6b251fc9 AA |
674 | ret = 0; |
675 | set = false; | |
bae473a4 | 676 | if (pmd_none(*fe->pmd)) { |
6b251fc9 | 677 | if (userfaultfd_missing(vma)) { |
bae473a4 KS |
678 | spin_unlock(fe->ptl); |
679 | ret = handle_userfault(fe, VM_UFFD_MISSING); | |
6b251fc9 AA |
680 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
681 | } else { | |
bae473a4 KS |
682 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
683 | haddr, fe->pmd, zero_page); | |
684 | spin_unlock(fe->ptl); | |
6b251fc9 AA |
685 | set = true; |
686 | } | |
687 | } else | |
bae473a4 | 688 | spin_unlock(fe->ptl); |
6fcb52a5 | 689 | if (!set) |
bae473a4 | 690 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 691 | return ret; |
71e3aac0 | 692 | } |
444eb2a4 | 693 | gfp = alloc_hugepage_direct_gfpmask(vma); |
077fcf11 | 694 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
695 | if (unlikely(!page)) { |
696 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 697 | return VM_FAULT_FALLBACK; |
128ec037 | 698 | } |
9a982250 | 699 | prep_transhuge_page(page); |
bae473a4 | 700 | return __do_huge_pmd_anonymous_page(fe, page, gfp); |
71e3aac0 AA |
701 | } |
702 | ||
ae18d6dc | 703 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
f25748e3 | 704 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write) |
5cad465d MW |
705 | { |
706 | struct mm_struct *mm = vma->vm_mm; | |
707 | pmd_t entry; | |
708 | spinlock_t *ptl; | |
709 | ||
710 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
711 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
712 | if (pfn_t_devmap(pfn)) | |
713 | entry = pmd_mkdevmap(entry); | |
01871e59 RZ |
714 | if (write) { |
715 | entry = pmd_mkyoung(pmd_mkdirty(entry)); | |
716 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 717 | } |
01871e59 RZ |
718 | set_pmd_at(mm, addr, pmd, entry); |
719 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 720 | spin_unlock(ptl); |
5cad465d MW |
721 | } |
722 | ||
723 | int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, | |
f25748e3 | 724 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
725 | { |
726 | pgprot_t pgprot = vma->vm_page_prot; | |
727 | /* | |
728 | * If we had pmd_special, we could avoid all these restrictions, | |
729 | * but we need to be consistent with PTEs and architectures that | |
730 | * can't support a 'special' bit. | |
731 | */ | |
732 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
733 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
734 | (VM_PFNMAP|VM_MIXEDMAP)); | |
735 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
f25748e3 | 736 | BUG_ON(!pfn_t_devmap(pfn)); |
5cad465d MW |
737 | |
738 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
739 | return VM_FAULT_SIGBUS; | |
308a047c BP |
740 | |
741 | track_pfn_insert(vma, &pgprot, pfn); | |
742 | ||
ae18d6dc MW |
743 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write); |
744 | return VM_FAULT_NOPAGE; | |
5cad465d | 745 | } |
dee41079 | 746 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 747 | |
3565fce3 DW |
748 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
749 | pmd_t *pmd) | |
750 | { | |
751 | pmd_t _pmd; | |
752 | ||
753 | /* | |
754 | * We should set the dirty bit only for FOLL_WRITE but for now | |
755 | * the dirty bit in the pmd is meaningless. And if the dirty | |
756 | * bit will become meaningful and we'll only set it with | |
757 | * FOLL_WRITE, an atomic set_bit will be required on the pmd to | |
758 | * set the young bit, instead of the current set_pmd_at. | |
759 | */ | |
760 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
761 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, | |
762 | pmd, _pmd, 1)) | |
763 | update_mmu_cache_pmd(vma, addr, pmd); | |
764 | } | |
765 | ||
766 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
767 | pmd_t *pmd, int flags) | |
768 | { | |
769 | unsigned long pfn = pmd_pfn(*pmd); | |
770 | struct mm_struct *mm = vma->vm_mm; | |
771 | struct dev_pagemap *pgmap; | |
772 | struct page *page; | |
773 | ||
774 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
775 | ||
776 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
777 | return NULL; | |
778 | ||
779 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
780 | /* pass */; | |
781 | else | |
782 | return NULL; | |
783 | ||
784 | if (flags & FOLL_TOUCH) | |
785 | touch_pmd(vma, addr, pmd); | |
786 | ||
787 | /* | |
788 | * device mapped pages can only be returned if the | |
789 | * caller will manage the page reference count. | |
790 | */ | |
791 | if (!(flags & FOLL_GET)) | |
792 | return ERR_PTR(-EEXIST); | |
793 | ||
794 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
795 | pgmap = get_dev_pagemap(pfn, NULL); | |
796 | if (!pgmap) | |
797 | return ERR_PTR(-EFAULT); | |
798 | page = pfn_to_page(pfn); | |
799 | get_page(page); | |
800 | put_dev_pagemap(pgmap); | |
801 | ||
802 | return page; | |
803 | } | |
804 | ||
71e3aac0 AA |
805 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
806 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
807 | struct vm_area_struct *vma) | |
808 | { | |
c4088ebd | 809 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
810 | struct page *src_page; |
811 | pmd_t pmd; | |
12c9d70b | 812 | pgtable_t pgtable = NULL; |
628d47ce | 813 | int ret = -ENOMEM; |
71e3aac0 | 814 | |
628d47ce KS |
815 | /* Skip if can be re-fill on fault */ |
816 | if (!vma_is_anonymous(vma)) | |
817 | return 0; | |
818 | ||
819 | pgtable = pte_alloc_one(dst_mm, addr); | |
820 | if (unlikely(!pgtable)) | |
821 | goto out; | |
71e3aac0 | 822 | |
c4088ebd KS |
823 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
824 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
825 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
826 | |
827 | ret = -EAGAIN; | |
828 | pmd = *src_pmd; | |
628d47ce | 829 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
830 | pte_free(dst_mm, pgtable); |
831 | goto out_unlock; | |
832 | } | |
fc9fe822 | 833 | /* |
c4088ebd | 834 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
835 | * under splitting since we don't split the page itself, only pmd to |
836 | * a page table. | |
837 | */ | |
838 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 839 | struct page *zero_page; |
97ae1749 KS |
840 | /* |
841 | * get_huge_zero_page() will never allocate a new page here, | |
842 | * since we already have a zero page to copy. It just takes a | |
843 | * reference. | |
844 | */ | |
6fcb52a5 | 845 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 846 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 847 | zero_page); |
fc9fe822 KS |
848 | ret = 0; |
849 | goto out_unlock; | |
850 | } | |
de466bd6 | 851 | |
628d47ce KS |
852 | src_page = pmd_page(pmd); |
853 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
854 | get_page(src_page); | |
855 | page_dup_rmap(src_page, true); | |
856 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
857 | atomic_long_inc(&dst_mm->nr_ptes); | |
858 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); | |
71e3aac0 AA |
859 | |
860 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
861 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
862 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
863 | |
864 | ret = 0; | |
865 | out_unlock: | |
c4088ebd KS |
866 | spin_unlock(src_ptl); |
867 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
868 | out: |
869 | return ret; | |
870 | } | |
871 | ||
bae473a4 | 872 | void huge_pmd_set_accessed(struct fault_env *fe, pmd_t orig_pmd) |
a1dd450b WD |
873 | { |
874 | pmd_t entry; | |
875 | unsigned long haddr; | |
876 | ||
bae473a4 KS |
877 | fe->ptl = pmd_lock(fe->vma->vm_mm, fe->pmd); |
878 | if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) | |
a1dd450b WD |
879 | goto unlock; |
880 | ||
881 | entry = pmd_mkyoung(orig_pmd); | |
bae473a4 KS |
882 | haddr = fe->address & HPAGE_PMD_MASK; |
883 | if (pmdp_set_access_flags(fe->vma, haddr, fe->pmd, entry, | |
884 | fe->flags & FAULT_FLAG_WRITE)) | |
885 | update_mmu_cache_pmd(fe->vma, fe->address, fe->pmd); | |
a1dd450b WD |
886 | |
887 | unlock: | |
bae473a4 | 888 | spin_unlock(fe->ptl); |
a1dd450b WD |
889 | } |
890 | ||
bae473a4 KS |
891 | static int do_huge_pmd_wp_page_fallback(struct fault_env *fe, pmd_t orig_pmd, |
892 | struct page *page) | |
71e3aac0 | 893 | { |
bae473a4 KS |
894 | struct vm_area_struct *vma = fe->vma; |
895 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; | |
00501b53 | 896 | struct mem_cgroup *memcg; |
71e3aac0 AA |
897 | pgtable_t pgtable; |
898 | pmd_t _pmd; | |
899 | int ret = 0, i; | |
900 | struct page **pages; | |
2ec74c3e SG |
901 | unsigned long mmun_start; /* For mmu_notifiers */ |
902 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
903 | |
904 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
905 | GFP_KERNEL); | |
906 | if (unlikely(!pages)) { | |
907 | ret |= VM_FAULT_OOM; | |
908 | goto out; | |
909 | } | |
910 | ||
911 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f | 912 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
bae473a4 KS |
913 | __GFP_OTHER_NODE, vma, |
914 | fe->address, page_to_nid(page)); | |
b9bbfbe3 | 915 | if (unlikely(!pages[i] || |
bae473a4 KS |
916 | mem_cgroup_try_charge(pages[i], vma->vm_mm, |
917 | GFP_KERNEL, &memcg, false))) { | |
b9bbfbe3 | 918 | if (pages[i]) |
71e3aac0 | 919 | put_page(pages[i]); |
b9bbfbe3 | 920 | while (--i >= 0) { |
00501b53 JW |
921 | memcg = (void *)page_private(pages[i]); |
922 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
923 | mem_cgroup_cancel_charge(pages[i], memcg, |
924 | false); | |
b9bbfbe3 AA |
925 | put_page(pages[i]); |
926 | } | |
71e3aac0 AA |
927 | kfree(pages); |
928 | ret |= VM_FAULT_OOM; | |
929 | goto out; | |
930 | } | |
00501b53 | 931 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
932 | } |
933 | ||
934 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
935 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 936 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
937 | __SetPageUptodate(pages[i]); |
938 | cond_resched(); | |
939 | } | |
940 | ||
2ec74c3e SG |
941 | mmun_start = haddr; |
942 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 943 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 944 | |
bae473a4 KS |
945 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); |
946 | if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) | |
71e3aac0 | 947 | goto out_free_pages; |
309381fe | 948 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 949 | |
bae473a4 | 950 | pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd); |
71e3aac0 AA |
951 | /* leave pmd empty until pte is filled */ |
952 | ||
bae473a4 KS |
953 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, fe->pmd); |
954 | pmd_populate(vma->vm_mm, &_pmd, pgtable); | |
71e3aac0 AA |
955 | |
956 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 957 | pte_t entry; |
71e3aac0 AA |
958 | entry = mk_pte(pages[i], vma->vm_page_prot); |
959 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
960 | memcg = (void *)page_private(pages[i]); |
961 | set_page_private(pages[i], 0); | |
bae473a4 | 962 | page_add_new_anon_rmap(pages[i], fe->vma, haddr, false); |
f627c2f5 | 963 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 964 | lru_cache_add_active_or_unevictable(pages[i], vma); |
bae473a4 KS |
965 | fe->pte = pte_offset_map(&_pmd, haddr); |
966 | VM_BUG_ON(!pte_none(*fe->pte)); | |
967 | set_pte_at(vma->vm_mm, haddr, fe->pte, entry); | |
968 | pte_unmap(fe->pte); | |
71e3aac0 AA |
969 | } |
970 | kfree(pages); | |
971 | ||
71e3aac0 | 972 | smp_wmb(); /* make pte visible before pmd */ |
bae473a4 | 973 | pmd_populate(vma->vm_mm, fe->pmd, pgtable); |
d281ee61 | 974 | page_remove_rmap(page, true); |
bae473a4 | 975 | spin_unlock(fe->ptl); |
71e3aac0 | 976 | |
bae473a4 | 977 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 978 | |
71e3aac0 AA |
979 | ret |= VM_FAULT_WRITE; |
980 | put_page(page); | |
981 | ||
982 | out: | |
983 | return ret; | |
984 | ||
985 | out_free_pages: | |
bae473a4 KS |
986 | spin_unlock(fe->ptl); |
987 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); | |
b9bbfbe3 | 988 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
989 | memcg = (void *)page_private(pages[i]); |
990 | set_page_private(pages[i], 0); | |
f627c2f5 | 991 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 992 | put_page(pages[i]); |
b9bbfbe3 | 993 | } |
71e3aac0 AA |
994 | kfree(pages); |
995 | goto out; | |
996 | } | |
997 | ||
bae473a4 | 998 | int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd) |
71e3aac0 | 999 | { |
bae473a4 | 1000 | struct vm_area_struct *vma = fe->vma; |
93b4796d | 1001 | struct page *page = NULL, *new_page; |
00501b53 | 1002 | struct mem_cgroup *memcg; |
bae473a4 | 1003 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; |
2ec74c3e SG |
1004 | unsigned long mmun_start; /* For mmu_notifiers */ |
1005 | unsigned long mmun_end; /* For mmu_notifiers */ | |
3b363692 | 1006 | gfp_t huge_gfp; /* for allocation and charge */ |
bae473a4 | 1007 | int ret = 0; |
71e3aac0 | 1008 | |
bae473a4 | 1009 | fe->ptl = pmd_lockptr(vma->vm_mm, fe->pmd); |
81d1b09c | 1010 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1011 | if (is_huge_zero_pmd(orig_pmd)) |
1012 | goto alloc; | |
bae473a4 KS |
1013 | spin_lock(fe->ptl); |
1014 | if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) | |
71e3aac0 AA |
1015 | goto out_unlock; |
1016 | ||
1017 | page = pmd_page(orig_pmd); | |
309381fe | 1018 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1019 | /* |
1020 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1021 | * part. |
1f25fe20 | 1022 | */ |
6d0a07ed | 1023 | if (page_trans_huge_mapcount(page, NULL) == 1) { |
71e3aac0 AA |
1024 | pmd_t entry; |
1025 | entry = pmd_mkyoung(orig_pmd); | |
1026 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
bae473a4 KS |
1027 | if (pmdp_set_access_flags(vma, haddr, fe->pmd, entry, 1)) |
1028 | update_mmu_cache_pmd(vma, fe->address, fe->pmd); | |
71e3aac0 AA |
1029 | ret |= VM_FAULT_WRITE; |
1030 | goto out_unlock; | |
1031 | } | |
ddc58f27 | 1032 | get_page(page); |
bae473a4 | 1033 | spin_unlock(fe->ptl); |
93b4796d | 1034 | alloc: |
71e3aac0 | 1035 | if (transparent_hugepage_enabled(vma) && |
077fcf11 | 1036 | !transparent_hugepage_debug_cow()) { |
444eb2a4 | 1037 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
3b363692 | 1038 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); |
077fcf11 | 1039 | } else |
71e3aac0 AA |
1040 | new_page = NULL; |
1041 | ||
9a982250 KS |
1042 | if (likely(new_page)) { |
1043 | prep_transhuge_page(new_page); | |
1044 | } else { | |
eecc1e42 | 1045 | if (!page) { |
bae473a4 | 1046 | split_huge_pmd(vma, fe->pmd, fe->address); |
e9b71ca9 | 1047 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1048 | } else { |
bae473a4 | 1049 | ret = do_huge_pmd_wp_page_fallback(fe, orig_pmd, page); |
9845cbbd | 1050 | if (ret & VM_FAULT_OOM) { |
bae473a4 | 1051 | split_huge_pmd(vma, fe->pmd, fe->address); |
9845cbbd KS |
1052 | ret |= VM_FAULT_FALLBACK; |
1053 | } | |
ddc58f27 | 1054 | put_page(page); |
93b4796d | 1055 | } |
17766dde | 1056 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1057 | goto out; |
1058 | } | |
1059 | ||
bae473a4 KS |
1060 | if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, |
1061 | huge_gfp, &memcg, true))) { | |
b9bbfbe3 | 1062 | put_page(new_page); |
bae473a4 KS |
1063 | split_huge_pmd(vma, fe->pmd, fe->address); |
1064 | if (page) | |
ddc58f27 | 1065 | put_page(page); |
9845cbbd | 1066 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1067 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1068 | goto out; |
1069 | } | |
1070 | ||
17766dde DR |
1071 | count_vm_event(THP_FAULT_ALLOC); |
1072 | ||
eecc1e42 | 1073 | if (!page) |
93b4796d KS |
1074 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); |
1075 | else | |
1076 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1077 | __SetPageUptodate(new_page); |
1078 | ||
2ec74c3e SG |
1079 | mmun_start = haddr; |
1080 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1081 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1082 | |
bae473a4 | 1083 | spin_lock(fe->ptl); |
93b4796d | 1084 | if (page) |
ddc58f27 | 1085 | put_page(page); |
bae473a4 KS |
1086 | if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) { |
1087 | spin_unlock(fe->ptl); | |
f627c2f5 | 1088 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1089 | put_page(new_page); |
2ec74c3e | 1090 | goto out_mn; |
b9bbfbe3 | 1091 | } else { |
71e3aac0 | 1092 | pmd_t entry; |
3122359a KS |
1093 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1094 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
bae473a4 | 1095 | pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd); |
d281ee61 | 1096 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1097 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1098 | lru_cache_add_active_or_unevictable(new_page, vma); |
bae473a4 KS |
1099 | set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry); |
1100 | update_mmu_cache_pmd(vma, fe->address, fe->pmd); | |
eecc1e42 | 1101 | if (!page) { |
bae473a4 | 1102 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1103 | } else { |
309381fe | 1104 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1105 | page_remove_rmap(page, true); |
93b4796d KS |
1106 | put_page(page); |
1107 | } | |
71e3aac0 AA |
1108 | ret |= VM_FAULT_WRITE; |
1109 | } | |
bae473a4 | 1110 | spin_unlock(fe->ptl); |
2ec74c3e | 1111 | out_mn: |
bae473a4 | 1112 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
71e3aac0 AA |
1113 | out: |
1114 | return ret; | |
2ec74c3e | 1115 | out_unlock: |
bae473a4 | 1116 | spin_unlock(fe->ptl); |
2ec74c3e | 1117 | return ret; |
71e3aac0 AA |
1118 | } |
1119 | ||
b676b293 | 1120 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1121 | unsigned long addr, |
1122 | pmd_t *pmd, | |
1123 | unsigned int flags) | |
1124 | { | |
b676b293 | 1125 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1126 | struct page *page = NULL; |
1127 | ||
c4088ebd | 1128 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 AA |
1129 | |
1130 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1131 | goto out; | |
1132 | ||
85facf25 KS |
1133 | /* Avoid dumping huge zero page */ |
1134 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1135 | return ERR_PTR(-EFAULT); | |
1136 | ||
2b4847e7 | 1137 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1138 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1139 | goto out; |
1140 | ||
71e3aac0 | 1141 | page = pmd_page(*pmd); |
ca120cf6 | 1142 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 DW |
1143 | if (flags & FOLL_TOUCH) |
1144 | touch_pmd(vma, addr, pmd); | |
de60f5f1 | 1145 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1146 | /* |
1147 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1148 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1149 | * | |
9a73f61b KS |
1150 | * For anon THP: |
1151 | * | |
e90309c9 KS |
1152 | * In most cases the pmd is the only mapping of the page as we |
1153 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1154 | * writable private mappings in populate_vma_page_range(). | |
1155 | * | |
1156 | * The only scenario when we have the page shared here is if we | |
1157 | * mlocking read-only mapping shared over fork(). We skip | |
1158 | * mlocking such pages. | |
9a73f61b KS |
1159 | * |
1160 | * For file THP: | |
1161 | * | |
1162 | * We can expect PageDoubleMap() to be stable under page lock: | |
1163 | * for file pages we set it in page_add_file_rmap(), which | |
1164 | * requires page to be locked. | |
e90309c9 | 1165 | */ |
9a73f61b KS |
1166 | |
1167 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1168 | goto skip_mlock; | |
1169 | if (PageDoubleMap(page) || !page->mapping) | |
1170 | goto skip_mlock; | |
1171 | if (!trylock_page(page)) | |
1172 | goto skip_mlock; | |
1173 | lru_add_drain(); | |
1174 | if (page->mapping && !PageDoubleMap(page)) | |
1175 | mlock_vma_page(page); | |
1176 | unlock_page(page); | |
b676b293 | 1177 | } |
9a73f61b | 1178 | skip_mlock: |
71e3aac0 | 1179 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1180 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1181 | if (flags & FOLL_GET) |
ddc58f27 | 1182 | get_page(page); |
71e3aac0 AA |
1183 | |
1184 | out: | |
1185 | return page; | |
1186 | } | |
1187 | ||
d10e63f2 | 1188 | /* NUMA hinting page fault entry point for trans huge pmds */ |
bae473a4 | 1189 | int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t pmd) |
d10e63f2 | 1190 | { |
bae473a4 | 1191 | struct vm_area_struct *vma = fe->vma; |
b8916634 | 1192 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1193 | struct page *page; |
bae473a4 | 1194 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; |
8191acbd | 1195 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1196 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1197 | bool page_locked; |
1198 | bool migrated = false; | |
b191f9b1 | 1199 | bool was_writable; |
6688cc05 | 1200 | int flags = 0; |
d10e63f2 | 1201 | |
bae473a4 KS |
1202 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); |
1203 | if (unlikely(!pmd_same(pmd, *fe->pmd))) | |
d10e63f2 MG |
1204 | goto out_unlock; |
1205 | ||
de466bd6 MG |
1206 | /* |
1207 | * If there are potential migrations, wait for completion and retry | |
1208 | * without disrupting NUMA hinting information. Do not relock and | |
1209 | * check_same as the page may no longer be mapped. | |
1210 | */ | |
bae473a4 KS |
1211 | if (unlikely(pmd_trans_migrating(*fe->pmd))) { |
1212 | page = pmd_page(*fe->pmd); | |
1213 | spin_unlock(fe->ptl); | |
5d833062 | 1214 | wait_on_page_locked(page); |
de466bd6 MG |
1215 | goto out; |
1216 | } | |
1217 | ||
d10e63f2 | 1218 | page = pmd_page(pmd); |
a1a46184 | 1219 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1220 | page_nid = page_to_nid(page); |
90572890 | 1221 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1222 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1223 | if (page_nid == this_nid) { |
03c5a6e1 | 1224 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1225 | flags |= TNF_FAULT_LOCAL; |
1226 | } | |
4daae3b4 | 1227 | |
bea66fbd | 1228 | /* See similar comment in do_numa_page for explanation */ |
d59dc7bc | 1229 | if (!pmd_write(pmd)) |
6688cc05 PZ |
1230 | flags |= TNF_NO_GROUP; |
1231 | ||
ff9042b1 MG |
1232 | /* |
1233 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1234 | * page_table_lock if at all possible | |
1235 | */ | |
b8916634 MG |
1236 | page_locked = trylock_page(page); |
1237 | target_nid = mpol_misplaced(page, vma, haddr); | |
1238 | if (target_nid == -1) { | |
1239 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1240 | if (page_locked) |
b8916634 | 1241 | goto clear_pmdnuma; |
2b4847e7 | 1242 | } |
4daae3b4 | 1243 | |
de466bd6 | 1244 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1245 | if (!page_locked) { |
bae473a4 | 1246 | spin_unlock(fe->ptl); |
b8916634 | 1247 | wait_on_page_locked(page); |
a54a407f | 1248 | page_nid = -1; |
b8916634 MG |
1249 | goto out; |
1250 | } | |
1251 | ||
2b4847e7 MG |
1252 | /* |
1253 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1254 | * to serialises splits | |
1255 | */ | |
b8916634 | 1256 | get_page(page); |
bae473a4 | 1257 | spin_unlock(fe->ptl); |
b8916634 | 1258 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1259 | |
c69307d5 | 1260 | /* Confirm the PMD did not change while page_table_lock was released */ |
bae473a4 KS |
1261 | spin_lock(fe->ptl); |
1262 | if (unlikely(!pmd_same(pmd, *fe->pmd))) { | |
b32967ff MG |
1263 | unlock_page(page); |
1264 | put_page(page); | |
a54a407f | 1265 | page_nid = -1; |
4daae3b4 | 1266 | goto out_unlock; |
b32967ff | 1267 | } |
ff9042b1 | 1268 | |
c3a489ca MG |
1269 | /* Bail if we fail to protect against THP splits for any reason */ |
1270 | if (unlikely(!anon_vma)) { | |
1271 | put_page(page); | |
1272 | page_nid = -1; | |
1273 | goto clear_pmdnuma; | |
1274 | } | |
1275 | ||
a54a407f MG |
1276 | /* |
1277 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1278 | * and access rights restored. |
a54a407f | 1279 | */ |
bae473a4 KS |
1280 | spin_unlock(fe->ptl); |
1281 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, | |
1282 | fe->pmd, pmd, fe->address, page, target_nid); | |
6688cc05 PZ |
1283 | if (migrated) { |
1284 | flags |= TNF_MIGRATED; | |
8191acbd | 1285 | page_nid = target_nid; |
074c2381 MG |
1286 | } else |
1287 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1288 | |
8191acbd | 1289 | goto out; |
b32967ff | 1290 | clear_pmdnuma: |
a54a407f | 1291 | BUG_ON(!PageLocked(page)); |
b191f9b1 | 1292 | was_writable = pmd_write(pmd); |
4d942466 | 1293 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1294 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1295 | if (was_writable) |
1296 | pmd = pmd_mkwrite(pmd); | |
bae473a4 KS |
1297 | set_pmd_at(vma->vm_mm, haddr, fe->pmd, pmd); |
1298 | update_mmu_cache_pmd(vma, fe->address, fe->pmd); | |
a54a407f | 1299 | unlock_page(page); |
d10e63f2 | 1300 | out_unlock: |
bae473a4 | 1301 | spin_unlock(fe->ptl); |
b8916634 MG |
1302 | |
1303 | out: | |
1304 | if (anon_vma) | |
1305 | page_unlock_anon_vma_read(anon_vma); | |
1306 | ||
8191acbd | 1307 | if (page_nid != -1) |
bae473a4 | 1308 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, fe->flags); |
8191acbd | 1309 | |
d10e63f2 MG |
1310 | return 0; |
1311 | } | |
1312 | ||
319904ad HY |
1313 | /* |
1314 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1315 | * Otherwise, return false. | |
1316 | */ | |
1317 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1318 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1319 | { |
1320 | spinlock_t *ptl; | |
1321 | pmd_t orig_pmd; | |
1322 | struct page *page; | |
1323 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1324 | bool ret = false; |
b8d3c4c3 | 1325 | |
b6ec57f4 KS |
1326 | ptl = pmd_trans_huge_lock(pmd, vma); |
1327 | if (!ptl) | |
25eedabe | 1328 | goto out_unlocked; |
b8d3c4c3 MK |
1329 | |
1330 | orig_pmd = *pmd; | |
319904ad | 1331 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1332 | goto out; |
b8d3c4c3 MK |
1333 | |
1334 | page = pmd_page(orig_pmd); | |
1335 | /* | |
1336 | * If other processes are mapping this page, we couldn't discard | |
1337 | * the page unless they all do MADV_FREE so let's skip the page. | |
1338 | */ | |
1339 | if (page_mapcount(page) != 1) | |
1340 | goto out; | |
1341 | ||
1342 | if (!trylock_page(page)) | |
1343 | goto out; | |
1344 | ||
1345 | /* | |
1346 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1347 | * will deactivate only them. | |
1348 | */ | |
1349 | if (next - addr != HPAGE_PMD_SIZE) { | |
1350 | get_page(page); | |
1351 | spin_unlock(ptl); | |
9818b8cd | 1352 | split_huge_page(page); |
b8d3c4c3 MK |
1353 | put_page(page); |
1354 | unlock_page(page); | |
b8d3c4c3 MK |
1355 | goto out_unlocked; |
1356 | } | |
1357 | ||
1358 | if (PageDirty(page)) | |
1359 | ClearPageDirty(page); | |
1360 | unlock_page(page); | |
1361 | ||
1362 | if (PageActive(page)) | |
1363 | deactivate_page(page); | |
1364 | ||
1365 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { | |
1366 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1367 | tlb->fullmm); | |
1368 | orig_pmd = pmd_mkold(orig_pmd); | |
1369 | orig_pmd = pmd_mkclean(orig_pmd); | |
1370 | ||
1371 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1372 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1373 | } | |
319904ad | 1374 | ret = true; |
b8d3c4c3 MK |
1375 | out: |
1376 | spin_unlock(ptl); | |
1377 | out_unlocked: | |
1378 | return ret; | |
1379 | } | |
1380 | ||
71e3aac0 | 1381 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1382 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1383 | { |
da146769 | 1384 | pmd_t orig_pmd; |
bf929152 | 1385 | spinlock_t *ptl; |
71e3aac0 | 1386 | |
b6ec57f4 KS |
1387 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1388 | if (!ptl) | |
da146769 KS |
1389 | return 0; |
1390 | /* | |
1391 | * For architectures like ppc64 we look at deposited pgtable | |
1392 | * when calling pmdp_huge_get_and_clear. So do the | |
1393 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1394 | * operations. | |
1395 | */ | |
1396 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1397 | tlb->fullmm); | |
1398 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1399 | if (vma_is_dax(vma)) { | |
1400 | spin_unlock(ptl); | |
1401 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1402 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 KS |
1403 | } else if (is_huge_zero_pmd(orig_pmd)) { |
1404 | pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd)); | |
1405 | atomic_long_dec(&tlb->mm->nr_ptes); | |
1406 | spin_unlock(ptl); | |
c0f2e176 | 1407 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 KS |
1408 | } else { |
1409 | struct page *page = pmd_page(orig_pmd); | |
d281ee61 | 1410 | page_remove_rmap(page, true); |
da146769 | 1411 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
da146769 | 1412 | VM_BUG_ON_PAGE(!PageHead(page), page); |
b5072380 KS |
1413 | if (PageAnon(page)) { |
1414 | pgtable_t pgtable; | |
1415 | pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); | |
1416 | pte_free(tlb->mm, pgtable); | |
1417 | atomic_long_dec(&tlb->mm->nr_ptes); | |
1418 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1419 | } else { | |
1420 | add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); | |
1421 | } | |
da146769 | 1422 | spin_unlock(ptl); |
e77b0852 | 1423 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); |
025c5b24 | 1424 | } |
da146769 | 1425 | return 1; |
71e3aac0 AA |
1426 | } |
1427 | ||
bf8616d5 | 1428 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1429 | unsigned long new_addr, unsigned long old_end, |
5d190420 | 1430 | pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) |
37a1c49a | 1431 | { |
bf929152 | 1432 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1433 | pmd_t pmd; |
37a1c49a | 1434 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1435 | bool force_flush = false; |
37a1c49a AA |
1436 | |
1437 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1438 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1439 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1440 | return false; |
37a1c49a AA |
1441 | |
1442 | /* | |
1443 | * The destination pmd shouldn't be established, free_pgtables() | |
1444 | * should have release it. | |
1445 | */ | |
1446 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1447 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1448 | return false; |
37a1c49a AA |
1449 | } |
1450 | ||
bf929152 KS |
1451 | /* |
1452 | * We don't have to worry about the ordering of src and dst | |
1453 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1454 | */ | |
b6ec57f4 KS |
1455 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1456 | if (old_ptl) { | |
bf929152 KS |
1457 | new_ptl = pmd_lockptr(mm, new_pmd); |
1458 | if (new_ptl != old_ptl) | |
1459 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1460 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
a2ce2666 AL |
1461 | if (pmd_present(pmd) && pmd_dirty(pmd)) |
1462 | force_flush = true; | |
025c5b24 | 1463 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1464 | |
69a8ec2d KS |
1465 | if (pmd_move_must_withdraw(new_ptl, old_ptl) && |
1466 | vma_is_anonymous(vma)) { | |
b3084f4d | 1467 | pgtable_t pgtable; |
3592806c KS |
1468 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1469 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1470 | } |
b3084f4d AK |
1471 | set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); |
1472 | if (new_ptl != old_ptl) | |
1473 | spin_unlock(new_ptl); | |
5d190420 AL |
1474 | if (force_flush) |
1475 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
1476 | else | |
1477 | *need_flush = true; | |
bf929152 | 1478 | spin_unlock(old_ptl); |
4b471e88 | 1479 | return true; |
37a1c49a | 1480 | } |
4b471e88 | 1481 | return false; |
37a1c49a AA |
1482 | } |
1483 | ||
f123d74a MG |
1484 | /* |
1485 | * Returns | |
1486 | * - 0 if PMD could not be locked | |
1487 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1488 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1489 | */ | |
cd7548ab | 1490 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1491 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1492 | { |
1493 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1494 | spinlock_t *ptl; |
cd7548ab JW |
1495 | int ret = 0; |
1496 | ||
b6ec57f4 KS |
1497 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1498 | if (ptl) { | |
025c5b24 | 1499 | pmd_t entry; |
b191f9b1 | 1500 | bool preserve_write = prot_numa && pmd_write(*pmd); |
ba68bc01 | 1501 | ret = 1; |
e944fd67 MG |
1502 | |
1503 | /* | |
1504 | * Avoid trapping faults against the zero page. The read-only | |
1505 | * data is likely to be read-cached on the local CPU and | |
1506 | * local/remote hits to the zero page are not interesting. | |
1507 | */ | |
1508 | if (prot_numa && is_huge_zero_pmd(*pmd)) { | |
1509 | spin_unlock(ptl); | |
ba68bc01 | 1510 | return ret; |
e944fd67 MG |
1511 | } |
1512 | ||
10c1045f | 1513 | if (!prot_numa || !pmd_protnone(*pmd)) { |
8809aa2d | 1514 | entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd); |
10c1045f | 1515 | entry = pmd_modify(entry, newprot); |
b191f9b1 MG |
1516 | if (preserve_write) |
1517 | entry = pmd_mkwrite(entry); | |
10c1045f MG |
1518 | ret = HPAGE_PMD_NR; |
1519 | set_pmd_at(mm, addr, pmd, entry); | |
b237aded KS |
1520 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && |
1521 | pmd_write(entry)); | |
10c1045f | 1522 | } |
bf929152 | 1523 | spin_unlock(ptl); |
025c5b24 NH |
1524 | } |
1525 | ||
1526 | return ret; | |
1527 | } | |
1528 | ||
1529 | /* | |
8f19b0c0 | 1530 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1531 | * |
8f19b0c0 HY |
1532 | * Note that if it returns page table lock pointer, this routine returns without |
1533 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1534 | */ |
b6ec57f4 | 1535 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1536 | { |
b6ec57f4 KS |
1537 | spinlock_t *ptl; |
1538 | ptl = pmd_lock(vma->vm_mm, pmd); | |
5c7fb56e | 1539 | if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd))) |
b6ec57f4 KS |
1540 | return ptl; |
1541 | spin_unlock(ptl); | |
1542 | return NULL; | |
cd7548ab JW |
1543 | } |
1544 | ||
eef1b3ba KS |
1545 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1546 | unsigned long haddr, pmd_t *pmd) | |
1547 | { | |
1548 | struct mm_struct *mm = vma->vm_mm; | |
1549 | pgtable_t pgtable; | |
1550 | pmd_t _pmd; | |
1551 | int i; | |
1552 | ||
1553 | /* leave pmd empty until pte is filled */ | |
1554 | pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
1555 | ||
1556 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1557 | pmd_populate(mm, &_pmd, pgtable); | |
1558 | ||
1559 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1560 | pte_t *pte, entry; | |
1561 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1562 | entry = pte_mkspecial(entry); | |
1563 | pte = pte_offset_map(&_pmd, haddr); | |
1564 | VM_BUG_ON(!pte_none(*pte)); | |
1565 | set_pte_at(mm, haddr, pte, entry); | |
1566 | pte_unmap(pte); | |
1567 | } | |
1568 | smp_wmb(); /* make pte visible before pmd */ | |
1569 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
1570 | } |
1571 | ||
1572 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 1573 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
1574 | { |
1575 | struct mm_struct *mm = vma->vm_mm; | |
1576 | struct page *page; | |
1577 | pgtable_t pgtable; | |
1578 | pmd_t _pmd; | |
804dd150 | 1579 | bool young, write, dirty, soft_dirty; |
2ac015e2 | 1580 | unsigned long addr; |
eef1b3ba KS |
1581 | int i; |
1582 | ||
1583 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
1584 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1585 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
5c7fb56e | 1586 | VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)); |
eef1b3ba KS |
1587 | |
1588 | count_vm_event(THP_SPLIT_PMD); | |
1589 | ||
d21b9e57 KS |
1590 | if (!vma_is_anonymous(vma)) { |
1591 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
d21b9e57 KS |
1592 | if (vma_is_dax(vma)) |
1593 | return; | |
1594 | page = pmd_page(_pmd); | |
1595 | if (!PageReferenced(page) && pmd_young(_pmd)) | |
1596 | SetPageReferenced(page); | |
1597 | page_remove_rmap(page, true); | |
1598 | put_page(page); | |
1599 | add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); | |
eef1b3ba KS |
1600 | return; |
1601 | } else if (is_huge_zero_pmd(*pmd)) { | |
1602 | return __split_huge_zero_page_pmd(vma, haddr, pmd); | |
1603 | } | |
1604 | ||
1605 | page = pmd_page(*pmd); | |
1606 | VM_BUG_ON_PAGE(!page_count(page), page); | |
fe896d18 | 1607 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba KS |
1608 | write = pmd_write(*pmd); |
1609 | young = pmd_young(*pmd); | |
b8d3c4c3 | 1610 | dirty = pmd_dirty(*pmd); |
804dd150 | 1611 | soft_dirty = pmd_soft_dirty(*pmd); |
eef1b3ba | 1612 | |
c777e2a8 | 1613 | pmdp_huge_split_prepare(vma, haddr, pmd); |
eef1b3ba KS |
1614 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
1615 | pmd_populate(mm, &_pmd, pgtable); | |
1616 | ||
2ac015e2 | 1617 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
1618 | pte_t entry, *pte; |
1619 | /* | |
1620 | * Note that NUMA hinting access restrictions are not | |
1621 | * transferred to avoid any possibility of altering | |
1622 | * permissions across VMAs. | |
1623 | */ | |
ba988280 KS |
1624 | if (freeze) { |
1625 | swp_entry_t swp_entry; | |
1626 | swp_entry = make_migration_entry(page + i, write); | |
1627 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
1628 | if (soft_dirty) |
1629 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 1630 | } else { |
6d2329f8 | 1631 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 1632 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
1633 | if (!write) |
1634 | entry = pte_wrprotect(entry); | |
1635 | if (!young) | |
1636 | entry = pte_mkold(entry); | |
804dd150 AA |
1637 | if (soft_dirty) |
1638 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 1639 | } |
b8d3c4c3 MK |
1640 | if (dirty) |
1641 | SetPageDirty(page + i); | |
2ac015e2 | 1642 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 1643 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 1644 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
1645 | atomic_inc(&page[i]._mapcount); |
1646 | pte_unmap(pte); | |
1647 | } | |
1648 | ||
1649 | /* | |
1650 | * Set PG_double_map before dropping compound_mapcount to avoid | |
1651 | * false-negative page_mapped(). | |
1652 | */ | |
1653 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
1654 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
1655 | atomic_inc(&page[i]._mapcount); | |
1656 | } | |
1657 | ||
1658 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
1659 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 1660 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
1661 | if (TestClearPageDoubleMap(page)) { |
1662 | /* No need in mapcount reference anymore */ | |
1663 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
1664 | atomic_dec(&page[i]._mapcount); | |
1665 | } | |
1666 | } | |
1667 | ||
1668 | smp_wmb(); /* make pte visible before pmd */ | |
e9b61f19 KS |
1669 | /* |
1670 | * Up to this point the pmd is present and huge and userland has the | |
1671 | * whole access to the hugepage during the split (which happens in | |
1672 | * place). If we overwrite the pmd with the not-huge version pointing | |
1673 | * to the pte here (which of course we could if all CPUs were bug | |
1674 | * free), userland could trigger a small page size TLB miss on the | |
1675 | * small sized TLB while the hugepage TLB entry is still established in | |
1676 | * the huge TLB. Some CPU doesn't like that. | |
1677 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
1678 | * 383 on page 93. Intel should be safe but is also warns that it's | |
1679 | * only safe if the permission and cache attributes of the two entries | |
1680 | * loaded in the two TLB is identical (which should be the case here). | |
1681 | * But it is generally safer to never allow small and huge TLB entries | |
1682 | * for the same virtual address to be loaded simultaneously. So instead | |
1683 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
1684 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
1685 | * and pmd_trans_splitting must remain set at all times on the pmd | |
1686 | * until the split is complete for this pmd), then we flush the SMP TLB | |
1687 | * and finally we write the non-huge version of the pmd entry with | |
1688 | * pmd_populate. | |
1689 | */ | |
1690 | pmdp_invalidate(vma, haddr, pmd); | |
eef1b3ba | 1691 | pmd_populate(mm, pmd, pgtable); |
e9b61f19 KS |
1692 | |
1693 | if (freeze) { | |
2ac015e2 | 1694 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
1695 | page_remove_rmap(page + i, false); |
1696 | put_page(page + i); | |
1697 | } | |
1698 | } | |
eef1b3ba KS |
1699 | } |
1700 | ||
1701 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 1702 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
1703 | { |
1704 | spinlock_t *ptl; | |
1705 | struct mm_struct *mm = vma->vm_mm; | |
1706 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
1707 | ||
1708 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
1709 | ptl = pmd_lock(mm, pmd); | |
33f4751e NH |
1710 | |
1711 | /* | |
1712 | * If caller asks to setup a migration entries, we need a page to check | |
1713 | * pmd against. Otherwise we can end up replacing wrong page. | |
1714 | */ | |
1715 | VM_BUG_ON(freeze && !page); | |
1716 | if (page && page != pmd_page(*pmd)) | |
1717 | goto out; | |
1718 | ||
5c7fb56e | 1719 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 1720 | page = pmd_page(*pmd); |
5c7fb56e | 1721 | if (PageMlocked(page)) |
5f737714 | 1722 | clear_page_mlock(page); |
5c7fb56e | 1723 | } else if (!pmd_devmap(*pmd)) |
e90309c9 | 1724 | goto out; |
fec89c10 | 1725 | __split_huge_pmd_locked(vma, pmd, haddr, freeze); |
e90309c9 | 1726 | out: |
eef1b3ba KS |
1727 | spin_unlock(ptl); |
1728 | mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
1729 | } | |
1730 | ||
fec89c10 KS |
1731 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
1732 | bool freeze, struct page *page) | |
94fcc585 | 1733 | { |
f72e7dcd HD |
1734 | pgd_t *pgd; |
1735 | pud_t *pud; | |
94fcc585 AA |
1736 | pmd_t *pmd; |
1737 | ||
78ddc534 | 1738 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
1739 | if (!pgd_present(*pgd)) |
1740 | return; | |
1741 | ||
1742 | pud = pud_offset(pgd, address); | |
1743 | if (!pud_present(*pud)) | |
1744 | return; | |
1745 | ||
1746 | pmd = pmd_offset(pud, address); | |
fec89c10 | 1747 | |
33f4751e | 1748 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
1749 | } |
1750 | ||
e1b9996b | 1751 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
1752 | unsigned long start, |
1753 | unsigned long end, | |
1754 | long adjust_next) | |
1755 | { | |
1756 | /* | |
1757 | * If the new start address isn't hpage aligned and it could | |
1758 | * previously contain an hugepage: check if we need to split | |
1759 | * an huge pmd. | |
1760 | */ | |
1761 | if (start & ~HPAGE_PMD_MASK && | |
1762 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
1763 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 1764 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
1765 | |
1766 | /* | |
1767 | * If the new end address isn't hpage aligned and it could | |
1768 | * previously contain an hugepage: check if we need to split | |
1769 | * an huge pmd. | |
1770 | */ | |
1771 | if (end & ~HPAGE_PMD_MASK && | |
1772 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
1773 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 1774 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
1775 | |
1776 | /* | |
1777 | * If we're also updating the vma->vm_next->vm_start, if the new | |
1778 | * vm_next->vm_start isn't page aligned and it could previously | |
1779 | * contain an hugepage: check if we need to split an huge pmd. | |
1780 | */ | |
1781 | if (adjust_next > 0) { | |
1782 | struct vm_area_struct *next = vma->vm_next; | |
1783 | unsigned long nstart = next->vm_start; | |
1784 | nstart += adjust_next << PAGE_SHIFT; | |
1785 | if (nstart & ~HPAGE_PMD_MASK && | |
1786 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
1787 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 1788 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
1789 | } |
1790 | } | |
e9b61f19 | 1791 | |
fec89c10 | 1792 | static void freeze_page(struct page *page) |
e9b61f19 | 1793 | { |
baa355fd KS |
1794 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
1795 | TTU_RMAP_LOCKED; | |
fec89c10 | 1796 | int i, ret; |
e9b61f19 KS |
1797 | |
1798 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1799 | ||
baa355fd KS |
1800 | if (PageAnon(page)) |
1801 | ttu_flags |= TTU_MIGRATION; | |
1802 | ||
fec89c10 KS |
1803 | /* We only need TTU_SPLIT_HUGE_PMD once */ |
1804 | ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD); | |
1805 | for (i = 1; !ret && i < HPAGE_PMD_NR; i++) { | |
1806 | /* Cut short if the page is unmapped */ | |
1807 | if (page_count(page) == 1) | |
1808 | return; | |
e9b61f19 | 1809 | |
fec89c10 | 1810 | ret = try_to_unmap(page + i, ttu_flags); |
e9b61f19 | 1811 | } |
baa355fd | 1812 | VM_BUG_ON_PAGE(ret, page + i - 1); |
e9b61f19 KS |
1813 | } |
1814 | ||
fec89c10 | 1815 | static void unfreeze_page(struct page *page) |
e9b61f19 | 1816 | { |
fec89c10 | 1817 | int i; |
e9b61f19 | 1818 | |
fec89c10 KS |
1819 | for (i = 0; i < HPAGE_PMD_NR; i++) |
1820 | remove_migration_ptes(page + i, page + i, true); | |
e9b61f19 KS |
1821 | } |
1822 | ||
8df651c7 | 1823 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
1824 | struct lruvec *lruvec, struct list_head *list) |
1825 | { | |
e9b61f19 KS |
1826 | struct page *page_tail = head + tail; |
1827 | ||
8df651c7 | 1828 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
fe896d18 | 1829 | VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail); |
e9b61f19 KS |
1830 | |
1831 | /* | |
0139aa7b | 1832 | * tail_page->_refcount is zero and not changing from under us. But |
e9b61f19 | 1833 | * get_page_unless_zero() may be running from under us on the |
baa355fd KS |
1834 | * tail_page. If we used atomic_set() below instead of atomic_inc() or |
1835 | * atomic_add(), we would then run atomic_set() concurrently with | |
e9b61f19 KS |
1836 | * get_page_unless_zero(), and atomic_set() is implemented in C not |
1837 | * using locked ops. spin_unlock on x86 sometime uses locked ops | |
1838 | * because of PPro errata 66, 92, so unless somebody can guarantee | |
1839 | * atomic_set() here would be safe on all archs (and not only on x86), | |
baa355fd | 1840 | * it's safer to use atomic_inc()/atomic_add(). |
e9b61f19 | 1841 | */ |
baa355fd KS |
1842 | if (PageAnon(head)) { |
1843 | page_ref_inc(page_tail); | |
1844 | } else { | |
1845 | /* Additional pin to radix tree */ | |
1846 | page_ref_add(page_tail, 2); | |
1847 | } | |
e9b61f19 KS |
1848 | |
1849 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; | |
1850 | page_tail->flags |= (head->flags & | |
1851 | ((1L << PG_referenced) | | |
1852 | (1L << PG_swapbacked) | | |
1853 | (1L << PG_mlocked) | | |
1854 | (1L << PG_uptodate) | | |
1855 | (1L << PG_active) | | |
1856 | (1L << PG_locked) | | |
b8d3c4c3 MK |
1857 | (1L << PG_unevictable) | |
1858 | (1L << PG_dirty))); | |
e9b61f19 KS |
1859 | |
1860 | /* | |
1861 | * After clearing PageTail the gup refcount can be released. | |
1862 | * Page flags also must be visible before we make the page non-compound. | |
1863 | */ | |
1864 | smp_wmb(); | |
1865 | ||
1866 | clear_compound_head(page_tail); | |
1867 | ||
1868 | if (page_is_young(head)) | |
1869 | set_page_young(page_tail); | |
1870 | if (page_is_idle(head)) | |
1871 | set_page_idle(page_tail); | |
1872 | ||
1873 | /* ->mapping in first tail page is compound_mapcount */ | |
9a982250 | 1874 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
e9b61f19 KS |
1875 | page_tail); |
1876 | page_tail->mapping = head->mapping; | |
1877 | ||
1878 | page_tail->index = head->index + tail; | |
1879 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); | |
1880 | lru_add_page_tail(head, page_tail, lruvec, list); | |
e9b61f19 KS |
1881 | } |
1882 | ||
baa355fd KS |
1883 | static void __split_huge_page(struct page *page, struct list_head *list, |
1884 | unsigned long flags) | |
e9b61f19 KS |
1885 | { |
1886 | struct page *head = compound_head(page); | |
1887 | struct zone *zone = page_zone(head); | |
1888 | struct lruvec *lruvec; | |
baa355fd | 1889 | pgoff_t end = -1; |
8df651c7 | 1890 | int i; |
e9b61f19 | 1891 | |
599d0c95 | 1892 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
1893 | |
1894 | /* complete memcg works before add pages to LRU */ | |
1895 | mem_cgroup_split_huge_fixup(head); | |
1896 | ||
baa355fd KS |
1897 | if (!PageAnon(page)) |
1898 | end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); | |
1899 | ||
1900 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { | |
8df651c7 | 1901 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
1902 | /* Some pages can be beyond i_size: drop them from page cache */ |
1903 | if (head[i].index >= end) { | |
1904 | __ClearPageDirty(head + i); | |
1905 | __delete_from_page_cache(head + i, NULL); | |
800d8c63 KS |
1906 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
1907 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
1908 | put_page(head + i); |
1909 | } | |
1910 | } | |
e9b61f19 KS |
1911 | |
1912 | ClearPageCompound(head); | |
baa355fd KS |
1913 | /* See comment in __split_huge_page_tail() */ |
1914 | if (PageAnon(head)) { | |
1915 | page_ref_inc(head); | |
1916 | } else { | |
1917 | /* Additional pin to radix tree */ | |
1918 | page_ref_add(head, 2); | |
1919 | spin_unlock(&head->mapping->tree_lock); | |
1920 | } | |
1921 | ||
a52633d8 | 1922 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 1923 | |
fec89c10 | 1924 | unfreeze_page(head); |
e9b61f19 KS |
1925 | |
1926 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1927 | struct page *subpage = head + i; | |
1928 | if (subpage == page) | |
1929 | continue; | |
1930 | unlock_page(subpage); | |
1931 | ||
1932 | /* | |
1933 | * Subpages may be freed if there wasn't any mapping | |
1934 | * like if add_to_swap() is running on a lru page that | |
1935 | * had its mapping zapped. And freeing these pages | |
1936 | * requires taking the lru_lock so we do the put_page | |
1937 | * of the tail pages after the split is complete. | |
1938 | */ | |
1939 | put_page(subpage); | |
1940 | } | |
1941 | } | |
1942 | ||
b20ce5e0 KS |
1943 | int total_mapcount(struct page *page) |
1944 | { | |
dd78fedd | 1945 | int i, compound, ret; |
b20ce5e0 KS |
1946 | |
1947 | VM_BUG_ON_PAGE(PageTail(page), page); | |
1948 | ||
1949 | if (likely(!PageCompound(page))) | |
1950 | return atomic_read(&page->_mapcount) + 1; | |
1951 | ||
dd78fedd | 1952 | compound = compound_mapcount(page); |
b20ce5e0 | 1953 | if (PageHuge(page)) |
dd78fedd KS |
1954 | return compound; |
1955 | ret = compound; | |
b20ce5e0 KS |
1956 | for (i = 0; i < HPAGE_PMD_NR; i++) |
1957 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
1958 | /* File pages has compound_mapcount included in _mapcount */ |
1959 | if (!PageAnon(page)) | |
1960 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
1961 | if (PageDoubleMap(page)) |
1962 | ret -= HPAGE_PMD_NR; | |
1963 | return ret; | |
1964 | } | |
1965 | ||
6d0a07ed AA |
1966 | /* |
1967 | * This calculates accurately how many mappings a transparent hugepage | |
1968 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
1969 | * accuracy is primarily needed to know if copy-on-write faults can | |
1970 | * reuse the page and change the mapping to read-write instead of | |
1971 | * copying them. At the same time this returns the total_mapcount too. | |
1972 | * | |
1973 | * The function returns the highest mapcount any one of the subpages | |
1974 | * has. If the return value is one, even if different processes are | |
1975 | * mapping different subpages of the transparent hugepage, they can | |
1976 | * all reuse it, because each process is reusing a different subpage. | |
1977 | * | |
1978 | * The total_mapcount is instead counting all virtual mappings of the | |
1979 | * subpages. If the total_mapcount is equal to "one", it tells the | |
1980 | * caller all mappings belong to the same "mm" and in turn the | |
1981 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
1982 | * local one as no other process may be mapping any of the subpages. | |
1983 | * | |
1984 | * It would be more accurate to replace page_mapcount() with | |
1985 | * page_trans_huge_mapcount(), however we only use | |
1986 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
1987 | * need full accuracy to avoid breaking page pinning, because | |
1988 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
1989 | */ | |
1990 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
1991 | { | |
1992 | int i, ret, _total_mapcount, mapcount; | |
1993 | ||
1994 | /* hugetlbfs shouldn't call it */ | |
1995 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
1996 | ||
1997 | if (likely(!PageTransCompound(page))) { | |
1998 | mapcount = atomic_read(&page->_mapcount) + 1; | |
1999 | if (total_mapcount) | |
2000 | *total_mapcount = mapcount; | |
2001 | return mapcount; | |
2002 | } | |
2003 | ||
2004 | page = compound_head(page); | |
2005 | ||
2006 | _total_mapcount = ret = 0; | |
2007 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2008 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2009 | ret = max(ret, mapcount); | |
2010 | _total_mapcount += mapcount; | |
2011 | } | |
2012 | if (PageDoubleMap(page)) { | |
2013 | ret -= 1; | |
2014 | _total_mapcount -= HPAGE_PMD_NR; | |
2015 | } | |
2016 | mapcount = compound_mapcount(page); | |
2017 | ret += mapcount; | |
2018 | _total_mapcount += mapcount; | |
2019 | if (total_mapcount) | |
2020 | *total_mapcount = _total_mapcount; | |
2021 | return ret; | |
2022 | } | |
2023 | ||
e9b61f19 KS |
2024 | /* |
2025 | * This function splits huge page into normal pages. @page can point to any | |
2026 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2027 | * | |
2028 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2029 | * The huge page must be locked. | |
2030 | * | |
2031 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2032 | * | |
2033 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2034 | * the hugepage. | |
2035 | * | |
2036 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2037 | * they are not mapped. | |
2038 | * | |
2039 | * Returns 0 if the hugepage is split successfully. | |
2040 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2041 | * us. | |
2042 | */ | |
2043 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2044 | { | |
2045 | struct page *head = compound_head(page); | |
a3d0a918 | 2046 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2047 | struct anon_vma *anon_vma = NULL; |
2048 | struct address_space *mapping = NULL; | |
2049 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2050 | bool mlocked; |
0b9b6fff | 2051 | unsigned long flags; |
e9b61f19 KS |
2052 | |
2053 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 KS |
2054 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
2055 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
2056 | VM_BUG_ON_PAGE(!PageCompound(page), page); | |
2057 | ||
baa355fd KS |
2058 | if (PageAnon(head)) { |
2059 | /* | |
2060 | * The caller does not necessarily hold an mmap_sem that would | |
2061 | * prevent the anon_vma disappearing so we first we take a | |
2062 | * reference to it and then lock the anon_vma for write. This | |
2063 | * is similar to page_lock_anon_vma_read except the write lock | |
2064 | * is taken to serialise against parallel split or collapse | |
2065 | * operations. | |
2066 | */ | |
2067 | anon_vma = page_get_anon_vma(head); | |
2068 | if (!anon_vma) { | |
2069 | ret = -EBUSY; | |
2070 | goto out; | |
2071 | } | |
2072 | extra_pins = 0; | |
2073 | mapping = NULL; | |
2074 | anon_vma_lock_write(anon_vma); | |
2075 | } else { | |
2076 | mapping = head->mapping; | |
2077 | ||
2078 | /* Truncated ? */ | |
2079 | if (!mapping) { | |
2080 | ret = -EBUSY; | |
2081 | goto out; | |
2082 | } | |
2083 | ||
2084 | /* Addidional pins from radix tree */ | |
2085 | extra_pins = HPAGE_PMD_NR; | |
2086 | anon_vma = NULL; | |
2087 | i_mmap_lock_read(mapping); | |
e9b61f19 | 2088 | } |
e9b61f19 KS |
2089 | |
2090 | /* | |
2091 | * Racy check if we can split the page, before freeze_page() will | |
2092 | * split PMDs | |
2093 | */ | |
baa355fd | 2094 | if (total_mapcount(head) != page_count(head) - extra_pins - 1) { |
e9b61f19 KS |
2095 | ret = -EBUSY; |
2096 | goto out_unlock; | |
2097 | } | |
2098 | ||
d9654322 | 2099 | mlocked = PageMlocked(page); |
fec89c10 | 2100 | freeze_page(head); |
e9b61f19 KS |
2101 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2102 | ||
d9654322 KS |
2103 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2104 | if (mlocked) | |
2105 | lru_add_drain(); | |
2106 | ||
baa355fd | 2107 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2108 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2109 | |
2110 | if (mapping) { | |
2111 | void **pslot; | |
2112 | ||
2113 | spin_lock(&mapping->tree_lock); | |
2114 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
2115 | page_index(head)); | |
2116 | /* | |
2117 | * Check if the head page is present in radix tree. | |
2118 | * We assume all tail are present too, if head is there. | |
2119 | */ | |
2120 | if (radix_tree_deref_slot_protected(pslot, | |
2121 | &mapping->tree_lock) != head) | |
2122 | goto fail; | |
2123 | } | |
2124 | ||
0139aa7b | 2125 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2126 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2127 | count = page_count(head); |
2128 | mapcount = total_mapcount(head); | |
baa355fd | 2129 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2130 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2131 | pgdata->split_queue_len--; |
9a982250 KS |
2132 | list_del(page_deferred_list(head)); |
2133 | } | |
65c45377 | 2134 | if (mapping) |
11fb9989 | 2135 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd KS |
2136 | spin_unlock(&pgdata->split_queue_lock); |
2137 | __split_huge_page(page, list, flags); | |
e9b61f19 | 2138 | ret = 0; |
e9b61f19 | 2139 | } else { |
baa355fd KS |
2140 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2141 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2142 | mapcount, count); | |
2143 | if (PageTail(page)) | |
2144 | dump_page(head, NULL); | |
2145 | dump_page(page, "total_mapcount(head) > 0"); | |
2146 | BUG(); | |
2147 | } | |
2148 | spin_unlock(&pgdata->split_queue_lock); | |
2149 | fail: if (mapping) | |
2150 | spin_unlock(&mapping->tree_lock); | |
a52633d8 | 2151 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
fec89c10 | 2152 | unfreeze_page(head); |
e9b61f19 KS |
2153 | ret = -EBUSY; |
2154 | } | |
2155 | ||
2156 | out_unlock: | |
baa355fd KS |
2157 | if (anon_vma) { |
2158 | anon_vma_unlock_write(anon_vma); | |
2159 | put_anon_vma(anon_vma); | |
2160 | } | |
2161 | if (mapping) | |
2162 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2163 | out: |
2164 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2165 | return ret; | |
2166 | } | |
9a982250 KS |
2167 | |
2168 | void free_transhuge_page(struct page *page) | |
2169 | { | |
a3d0a918 | 2170 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2171 | unsigned long flags; |
2172 | ||
a3d0a918 | 2173 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2174 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2175 | pgdata->split_queue_len--; |
9a982250 KS |
2176 | list_del(page_deferred_list(page)); |
2177 | } | |
a3d0a918 | 2178 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2179 | free_compound_page(page); |
2180 | } | |
2181 | ||
2182 | void deferred_split_huge_page(struct page *page) | |
2183 | { | |
a3d0a918 | 2184 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2185 | unsigned long flags; |
2186 | ||
2187 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2188 | ||
a3d0a918 | 2189 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2190 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2191 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2192 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2193 | pgdata->split_queue_len++; | |
9a982250 | 2194 | } |
a3d0a918 | 2195 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2196 | } |
2197 | ||
2198 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2199 | struct shrink_control *sc) | |
2200 | { | |
a3d0a918 | 2201 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
cb8d68ec | 2202 | return ACCESS_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2203 | } |
2204 | ||
2205 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2206 | struct shrink_control *sc) | |
2207 | { | |
a3d0a918 | 2208 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2209 | unsigned long flags; |
2210 | LIST_HEAD(list), *pos, *next; | |
2211 | struct page *page; | |
2212 | int split = 0; | |
2213 | ||
a3d0a918 | 2214 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2215 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2216 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2217 | page = list_entry((void *)pos, struct page, mapping); |
2218 | page = compound_head(page); | |
e3ae1953 KS |
2219 | if (get_page_unless_zero(page)) { |
2220 | list_move(page_deferred_list(page), &list); | |
2221 | } else { | |
2222 | /* We lost race with put_compound_page() */ | |
9a982250 | 2223 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2224 | pgdata->split_queue_len--; |
9a982250 | 2225 | } |
e3ae1953 KS |
2226 | if (!--sc->nr_to_scan) |
2227 | break; | |
9a982250 | 2228 | } |
a3d0a918 | 2229 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2230 | |
2231 | list_for_each_safe(pos, next, &list) { | |
2232 | page = list_entry((void *)pos, struct page, mapping); | |
2233 | lock_page(page); | |
2234 | /* split_huge_page() removes page from list on success */ | |
2235 | if (!split_huge_page(page)) | |
2236 | split++; | |
2237 | unlock_page(page); | |
2238 | put_page(page); | |
2239 | } | |
2240 | ||
a3d0a918 KS |
2241 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2242 | list_splice_tail(&list, &pgdata->split_queue); | |
2243 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2244 | |
cb8d68ec KS |
2245 | /* |
2246 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2247 | * This can happen if pages were freed under us. | |
2248 | */ | |
2249 | if (!split && list_empty(&pgdata->split_queue)) | |
2250 | return SHRINK_STOP; | |
2251 | return split; | |
9a982250 KS |
2252 | } |
2253 | ||
2254 | static struct shrinker deferred_split_shrinker = { | |
2255 | .count_objects = deferred_split_count, | |
2256 | .scan_objects = deferred_split_scan, | |
2257 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2258 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2259 | }; |
49071d43 KS |
2260 | |
2261 | #ifdef CONFIG_DEBUG_FS | |
2262 | static int split_huge_pages_set(void *data, u64 val) | |
2263 | { | |
2264 | struct zone *zone; | |
2265 | struct page *page; | |
2266 | unsigned long pfn, max_zone_pfn; | |
2267 | unsigned long total = 0, split = 0; | |
2268 | ||
2269 | if (val != 1) | |
2270 | return -EINVAL; | |
2271 | ||
2272 | for_each_populated_zone(zone) { | |
2273 | max_zone_pfn = zone_end_pfn(zone); | |
2274 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2275 | if (!pfn_valid(pfn)) | |
2276 | continue; | |
2277 | ||
2278 | page = pfn_to_page(pfn); | |
2279 | if (!get_page_unless_zero(page)) | |
2280 | continue; | |
2281 | ||
2282 | if (zone != page_zone(page)) | |
2283 | goto next; | |
2284 | ||
baa355fd | 2285 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2286 | goto next; |
2287 | ||
2288 | total++; | |
2289 | lock_page(page); | |
2290 | if (!split_huge_page(page)) | |
2291 | split++; | |
2292 | unlock_page(page); | |
2293 | next: | |
2294 | put_page(page); | |
2295 | } | |
2296 | } | |
2297 | ||
145bdaa1 | 2298 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2299 | |
2300 | return 0; | |
2301 | } | |
2302 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2303 | "%llu\n"); | |
2304 | ||
2305 | static int __init split_huge_pages_debugfs(void) | |
2306 | { | |
2307 | void *ret; | |
2308 | ||
145bdaa1 | 2309 | ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
49071d43 KS |
2310 | &split_huge_pages_fops); |
2311 | if (!ret) | |
2312 | pr_warn("Failed to create split_huge_pages in debugfs"); | |
2313 | return 0; | |
2314 | } | |
2315 | late_initcall(split_huge_pages_debugfs); | |
2316 | #endif |