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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> | |
f7ccbae4 | 12 | #include <linux/sched/coredump.h> |
6a3827d7 | 13 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
14 | #include <linux/highmem.h> |
15 | #include <linux/hugetlb.h> | |
16 | #include <linux/mmu_notifier.h> | |
17 | #include <linux/rmap.h> | |
18 | #include <linux/swap.h> | |
97ae1749 | 19 | #include <linux/shrinker.h> |
ba76149f | 20 | #include <linux/mm_inline.h> |
e9b61f19 | 21 | #include <linux/swapops.h> |
4897c765 | 22 | #include <linux/dax.h> |
ba76149f | 23 | #include <linux/khugepaged.h> |
878aee7d | 24 | #include <linux/freezer.h> |
f25748e3 | 25 | #include <linux/pfn_t.h> |
a664b2d8 | 26 | #include <linux/mman.h> |
3565fce3 | 27 | #include <linux/memremap.h> |
325adeb5 | 28 | #include <linux/pagemap.h> |
49071d43 | 29 | #include <linux/debugfs.h> |
4daae3b4 | 30 | #include <linux/migrate.h> |
43b5fbbd | 31 | #include <linux/hashtable.h> |
6b251fc9 | 32 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 33 | #include <linux/page_idle.h> |
baa355fd | 34 | #include <linux/shmem_fs.h> |
97ae1749 | 35 | |
71e3aac0 AA |
36 | #include <asm/tlb.h> |
37 | #include <asm/pgalloc.h> | |
38 | #include "internal.h" | |
39 | ||
ba76149f | 40 | /* |
8bfa3f9a JW |
41 | * By default transparent hugepage support is disabled in order that avoid |
42 | * to risk increase the memory footprint of applications without a guaranteed | |
43 | * benefit. When transparent hugepage support is enabled, is for all mappings, | |
44 | * and khugepaged scans all mappings. | |
45 | * Defrag is invoked by khugepaged hugepage allocations and by page faults | |
46 | * for all hugepage allocations. | |
ba76149f | 47 | */ |
71e3aac0 | 48 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 49 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 50 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
51 | #endif |
52 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
53 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
54 | #endif | |
444eb2a4 | 55 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
56 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
57 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 58 | |
9a982250 | 59 | static struct shrinker deferred_split_shrinker; |
f000565a | 60 | |
97ae1749 | 61 | static atomic_t huge_zero_refcount; |
56873f43 | 62 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 63 | |
6fcb52a5 | 64 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
65 | { |
66 | struct page *zero_page; | |
67 | retry: | |
68 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 69 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
70 | |
71 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 72 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
73 | if (!zero_page) { |
74 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 75 | return NULL; |
d8a8e1f0 KS |
76 | } |
77 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 78 | preempt_disable(); |
5918d10a | 79 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 80 | preempt_enable(); |
5ddacbe9 | 81 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
82 | goto retry; |
83 | } | |
84 | ||
85 | /* We take additional reference here. It will be put back by shrinker */ | |
86 | atomic_set(&huge_zero_refcount, 2); | |
87 | preempt_enable(); | |
4db0c3c2 | 88 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
89 | } |
90 | ||
6fcb52a5 | 91 | static void put_huge_zero_page(void) |
4a6c1297 | 92 | { |
97ae1749 KS |
93 | /* |
94 | * Counter should never go to zero here. Only shrinker can put | |
95 | * last reference. | |
96 | */ | |
97 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
98 | } |
99 | ||
6fcb52a5 AL |
100 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
101 | { | |
102 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
103 | return READ_ONCE(huge_zero_page); | |
104 | ||
105 | if (!get_huge_zero_page()) | |
106 | return NULL; | |
107 | ||
108 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
109 | put_huge_zero_page(); | |
110 | ||
111 | return READ_ONCE(huge_zero_page); | |
112 | } | |
113 | ||
114 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
115 | { | |
116 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
117 | put_huge_zero_page(); | |
118 | } | |
119 | ||
48896466 GC |
120 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
121 | struct shrink_control *sc) | |
4a6c1297 | 122 | { |
48896466 GC |
123 | /* we can free zero page only if last reference remains */ |
124 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
125 | } | |
97ae1749 | 126 | |
48896466 GC |
127 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
128 | struct shrink_control *sc) | |
129 | { | |
97ae1749 | 130 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
131 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
132 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 133 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 134 | return HPAGE_PMD_NR; |
97ae1749 KS |
135 | } |
136 | ||
137 | return 0; | |
4a6c1297 KS |
138 | } |
139 | ||
97ae1749 | 140 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
141 | .count_objects = shrink_huge_zero_page_count, |
142 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
143 | .seeks = DEFAULT_SEEKS, |
144 | }; | |
145 | ||
71e3aac0 | 146 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
147 | static ssize_t enabled_show(struct kobject *kobj, |
148 | struct kobj_attribute *attr, char *buf) | |
149 | { | |
444eb2a4 MG |
150 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
151 | return sprintf(buf, "[always] madvise never\n"); | |
152 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
153 | return sprintf(buf, "always [madvise] never\n"); | |
154 | else | |
155 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 156 | } |
444eb2a4 | 157 | |
71e3aac0 AA |
158 | static ssize_t enabled_store(struct kobject *kobj, |
159 | struct kobj_attribute *attr, | |
160 | const char *buf, size_t count) | |
161 | { | |
21440d7e | 162 | ssize_t ret = count; |
ba76149f | 163 | |
21440d7e DR |
164 | if (!memcmp("always", buf, |
165 | min(sizeof("always")-1, count))) { | |
166 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
167 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
168 | } else if (!memcmp("madvise", buf, | |
169 | min(sizeof("madvise")-1, count))) { | |
170 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
171 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
172 | } else if (!memcmp("never", buf, | |
173 | min(sizeof("never")-1, count))) { | |
174 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
175 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
176 | } else | |
177 | ret = -EINVAL; | |
ba76149f AA |
178 | |
179 | if (ret > 0) { | |
b46e756f | 180 | int err = start_stop_khugepaged(); |
ba76149f AA |
181 | if (err) |
182 | ret = err; | |
183 | } | |
ba76149f | 184 | return ret; |
71e3aac0 AA |
185 | } |
186 | static struct kobj_attribute enabled_attr = | |
187 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
188 | ||
b46e756f | 189 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
190 | struct kobj_attribute *attr, char *buf, |
191 | enum transparent_hugepage_flag flag) | |
192 | { | |
e27e6151 BH |
193 | return sprintf(buf, "%d\n", |
194 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 195 | } |
e27e6151 | 196 | |
b46e756f | 197 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
198 | struct kobj_attribute *attr, |
199 | const char *buf, size_t count, | |
200 | enum transparent_hugepage_flag flag) | |
201 | { | |
e27e6151 BH |
202 | unsigned long value; |
203 | int ret; | |
204 | ||
205 | ret = kstrtoul(buf, 10, &value); | |
206 | if (ret < 0) | |
207 | return ret; | |
208 | if (value > 1) | |
209 | return -EINVAL; | |
210 | ||
211 | if (value) | |
71e3aac0 | 212 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 213 | else |
71e3aac0 | 214 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
215 | |
216 | return count; | |
217 | } | |
218 | ||
71e3aac0 AA |
219 | static ssize_t defrag_show(struct kobject *kobj, |
220 | struct kobj_attribute *attr, char *buf) | |
221 | { | |
444eb2a4 | 222 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 223 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 224 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
225 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
226 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
227 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
228 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
229 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
230 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 231 | } |
21440d7e | 232 | |
71e3aac0 AA |
233 | static ssize_t defrag_store(struct kobject *kobj, |
234 | struct kobj_attribute *attr, | |
235 | const char *buf, size_t count) | |
236 | { | |
21440d7e DR |
237 | if (!memcmp("always", buf, |
238 | min(sizeof("always")-1, count))) { | |
239 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
240 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
241 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
242 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
243 | } else if (!memcmp("defer+madvise", buf, |
244 | min(sizeof("defer+madvise")-1, count))) { | |
245 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
246 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
247 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
248 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
4fad7fb6 DR |
249 | } else if (!memcmp("defer", buf, |
250 | min(sizeof("defer")-1, count))) { | |
251 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
252 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
253 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
254 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
255 | } else if (!memcmp("madvise", buf, |
256 | min(sizeof("madvise")-1, count))) { | |
257 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
258 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
259 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
260 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
261 | } else if (!memcmp("never", buf, | |
262 | min(sizeof("never")-1, count))) { | |
263 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
264 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
265 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
266 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
267 | } else | |
268 | return -EINVAL; | |
269 | ||
270 | return count; | |
71e3aac0 AA |
271 | } |
272 | static struct kobj_attribute defrag_attr = | |
273 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
274 | ||
79da5407 KS |
275 | static ssize_t use_zero_page_show(struct kobject *kobj, |
276 | struct kobj_attribute *attr, char *buf) | |
277 | { | |
b46e756f | 278 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
279 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
280 | } | |
281 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
282 | struct kobj_attribute *attr, const char *buf, size_t count) | |
283 | { | |
b46e756f | 284 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
285 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
286 | } | |
287 | static struct kobj_attribute use_zero_page_attr = | |
288 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
289 | |
290 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
291 | struct kobj_attribute *attr, char *buf) | |
292 | { | |
293 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
294 | } | |
295 | static struct kobj_attribute hpage_pmd_size_attr = | |
296 | __ATTR_RO(hpage_pmd_size); | |
297 | ||
71e3aac0 AA |
298 | #ifdef CONFIG_DEBUG_VM |
299 | static ssize_t debug_cow_show(struct kobject *kobj, | |
300 | struct kobj_attribute *attr, char *buf) | |
301 | { | |
b46e756f | 302 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
303 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
304 | } | |
305 | static ssize_t debug_cow_store(struct kobject *kobj, | |
306 | struct kobj_attribute *attr, | |
307 | const char *buf, size_t count) | |
308 | { | |
b46e756f | 309 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
310 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
311 | } | |
312 | static struct kobj_attribute debug_cow_attr = | |
313 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
314 | #endif /* CONFIG_DEBUG_VM */ | |
315 | ||
316 | static struct attribute *hugepage_attr[] = { | |
317 | &enabled_attr.attr, | |
318 | &defrag_attr.attr, | |
79da5407 | 319 | &use_zero_page_attr.attr, |
49920d28 | 320 | &hpage_pmd_size_attr.attr, |
e496cf3d | 321 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
322 | &shmem_enabled_attr.attr, |
323 | #endif | |
71e3aac0 AA |
324 | #ifdef CONFIG_DEBUG_VM |
325 | &debug_cow_attr.attr, | |
326 | #endif | |
327 | NULL, | |
328 | }; | |
329 | ||
330 | static struct attribute_group hugepage_attr_group = { | |
331 | .attrs = hugepage_attr, | |
ba76149f AA |
332 | }; |
333 | ||
569e5590 | 334 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 335 | { |
71e3aac0 AA |
336 | int err; |
337 | ||
569e5590 SL |
338 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
339 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 340 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 341 | return -ENOMEM; |
ba76149f AA |
342 | } |
343 | ||
569e5590 | 344 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 345 | if (err) { |
ae3a8c1c | 346 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 347 | goto delete_obj; |
ba76149f AA |
348 | } |
349 | ||
569e5590 | 350 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 351 | if (err) { |
ae3a8c1c | 352 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 353 | goto remove_hp_group; |
ba76149f | 354 | } |
569e5590 SL |
355 | |
356 | return 0; | |
357 | ||
358 | remove_hp_group: | |
359 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
360 | delete_obj: | |
361 | kobject_put(*hugepage_kobj); | |
362 | return err; | |
363 | } | |
364 | ||
365 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
366 | { | |
367 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
368 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
369 | kobject_put(hugepage_kobj); | |
370 | } | |
371 | #else | |
372 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
373 | { | |
374 | return 0; | |
375 | } | |
376 | ||
377 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
378 | { | |
379 | } | |
380 | #endif /* CONFIG_SYSFS */ | |
381 | ||
382 | static int __init hugepage_init(void) | |
383 | { | |
384 | int err; | |
385 | struct kobject *hugepage_kobj; | |
386 | ||
387 | if (!has_transparent_hugepage()) { | |
388 | transparent_hugepage_flags = 0; | |
389 | return -EINVAL; | |
390 | } | |
391 | ||
ff20c2e0 KS |
392 | /* |
393 | * hugepages can't be allocated by the buddy allocator | |
394 | */ | |
395 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
396 | /* | |
397 | * we use page->mapping and page->index in second tail page | |
398 | * as list_head: assuming THP order >= 2 | |
399 | */ | |
400 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
401 | ||
569e5590 SL |
402 | err = hugepage_init_sysfs(&hugepage_kobj); |
403 | if (err) | |
65ebb64f | 404 | goto err_sysfs; |
ba76149f | 405 | |
b46e756f | 406 | err = khugepaged_init(); |
ba76149f | 407 | if (err) |
65ebb64f | 408 | goto err_slab; |
ba76149f | 409 | |
65ebb64f KS |
410 | err = register_shrinker(&huge_zero_page_shrinker); |
411 | if (err) | |
412 | goto err_hzp_shrinker; | |
9a982250 KS |
413 | err = register_shrinker(&deferred_split_shrinker); |
414 | if (err) | |
415 | goto err_split_shrinker; | |
97ae1749 | 416 | |
97562cd2 RR |
417 | /* |
418 | * By default disable transparent hugepages on smaller systems, | |
419 | * where the extra memory used could hurt more than TLB overhead | |
420 | * is likely to save. The admin can still enable it through /sys. | |
421 | */ | |
79553da2 | 422 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 423 | transparent_hugepage_flags = 0; |
79553da2 KS |
424 | return 0; |
425 | } | |
97562cd2 | 426 | |
79553da2 | 427 | err = start_stop_khugepaged(); |
65ebb64f KS |
428 | if (err) |
429 | goto err_khugepaged; | |
ba76149f | 430 | |
569e5590 | 431 | return 0; |
65ebb64f | 432 | err_khugepaged: |
9a982250 KS |
433 | unregister_shrinker(&deferred_split_shrinker); |
434 | err_split_shrinker: | |
65ebb64f KS |
435 | unregister_shrinker(&huge_zero_page_shrinker); |
436 | err_hzp_shrinker: | |
b46e756f | 437 | khugepaged_destroy(); |
65ebb64f | 438 | err_slab: |
569e5590 | 439 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 440 | err_sysfs: |
ba76149f | 441 | return err; |
71e3aac0 | 442 | } |
a64fb3cd | 443 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
444 | |
445 | static int __init setup_transparent_hugepage(char *str) | |
446 | { | |
447 | int ret = 0; | |
448 | if (!str) | |
449 | goto out; | |
450 | if (!strcmp(str, "always")) { | |
451 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
452 | &transparent_hugepage_flags); | |
453 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
454 | &transparent_hugepage_flags); | |
455 | ret = 1; | |
456 | } else if (!strcmp(str, "madvise")) { | |
457 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
458 | &transparent_hugepage_flags); | |
459 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
460 | &transparent_hugepage_flags); | |
461 | ret = 1; | |
462 | } else if (!strcmp(str, "never")) { | |
463 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
464 | &transparent_hugepage_flags); | |
465 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
466 | &transparent_hugepage_flags); | |
467 | ret = 1; | |
468 | } | |
469 | out: | |
470 | if (!ret) | |
ae3a8c1c | 471 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
472 | return ret; |
473 | } | |
474 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
475 | ||
b32967ff | 476 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
477 | { |
478 | if (likely(vma->vm_flags & VM_WRITE)) | |
479 | pmd = pmd_mkwrite(pmd); | |
480 | return pmd; | |
481 | } | |
482 | ||
9a982250 KS |
483 | static inline struct list_head *page_deferred_list(struct page *page) |
484 | { | |
485 | /* | |
486 | * ->lru in the tail pages is occupied by compound_head. | |
487 | * Let's use ->mapping + ->index in the second tail page as list_head. | |
488 | */ | |
489 | return (struct list_head *)&page[2].mapping; | |
490 | } | |
491 | ||
492 | void prep_transhuge_page(struct page *page) | |
493 | { | |
494 | /* | |
495 | * we use page->mapping and page->indexlru in second tail page | |
496 | * as list_head: assuming THP order >= 2 | |
497 | */ | |
9a982250 KS |
498 | |
499 | INIT_LIST_HEAD(page_deferred_list(page)); | |
500 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
501 | } | |
502 | ||
74d2fad1 TK |
503 | unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
504 | loff_t off, unsigned long flags, unsigned long size) | |
505 | { | |
506 | unsigned long addr; | |
507 | loff_t off_end = off + len; | |
508 | loff_t off_align = round_up(off, size); | |
509 | unsigned long len_pad; | |
510 | ||
511 | if (off_end <= off_align || (off_end - off_align) < size) | |
512 | return 0; | |
513 | ||
514 | len_pad = len + size; | |
515 | if (len_pad < len || (off + len_pad) < off) | |
516 | return 0; | |
517 | ||
518 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
519 | off >> PAGE_SHIFT, flags); | |
520 | if (IS_ERR_VALUE(addr)) | |
521 | return 0; | |
522 | ||
523 | addr += (off - addr) & (size - 1); | |
524 | return addr; | |
525 | } | |
526 | ||
527 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
528 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
529 | { | |
530 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
531 | ||
532 | if (addr) | |
533 | goto out; | |
534 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
535 | goto out; | |
536 | ||
537 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
538 | if (addr) | |
539 | return addr; | |
540 | ||
541 | out: | |
542 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
543 | } | |
544 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
545 | ||
82b0f8c3 | 546 | static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, |
bae473a4 | 547 | gfp_t gfp) |
71e3aac0 | 548 | { |
82b0f8c3 | 549 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 550 | struct mem_cgroup *memcg; |
71e3aac0 | 551 | pgtable_t pgtable; |
82b0f8c3 | 552 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 553 | |
309381fe | 554 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 555 | |
bae473a4 | 556 | if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
557 | put_page(page); |
558 | count_vm_event(THP_FAULT_FALLBACK); | |
559 | return VM_FAULT_FALLBACK; | |
560 | } | |
00501b53 | 561 | |
bae473a4 | 562 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
00501b53 | 563 | if (unlikely(!pgtable)) { |
f627c2f5 | 564 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 565 | put_page(page); |
71e3aac0 | 566 | return VM_FAULT_OOM; |
00501b53 | 567 | } |
71e3aac0 AA |
568 | |
569 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
52f37629 MK |
570 | /* |
571 | * The memory barrier inside __SetPageUptodate makes sure that | |
572 | * clear_huge_page writes become visible before the set_pmd_at() | |
573 | * write. | |
574 | */ | |
71e3aac0 AA |
575 | __SetPageUptodate(page); |
576 | ||
82b0f8c3 JK |
577 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
578 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
579 | spin_unlock(vmf->ptl); | |
f627c2f5 | 580 | mem_cgroup_cancel_charge(page, memcg, true); |
71e3aac0 | 581 | put_page(page); |
bae473a4 | 582 | pte_free(vma->vm_mm, pgtable); |
71e3aac0 AA |
583 | } else { |
584 | pmd_t entry; | |
6b251fc9 AA |
585 | |
586 | /* Deliver the page fault to userland */ | |
587 | if (userfaultfd_missing(vma)) { | |
588 | int ret; | |
589 | ||
82b0f8c3 | 590 | spin_unlock(vmf->ptl); |
f627c2f5 | 591 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 592 | put_page(page); |
bae473a4 | 593 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 594 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
595 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
596 | return ret; | |
597 | } | |
598 | ||
3122359a KS |
599 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
600 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
d281ee61 | 601 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 602 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 603 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
604 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
605 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 KS |
606 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
607 | atomic_long_inc(&vma->vm_mm->nr_ptes); | |
82b0f8c3 | 608 | spin_unlock(vmf->ptl); |
6b251fc9 | 609 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 AA |
610 | } |
611 | ||
aa2e878e | 612 | return 0; |
71e3aac0 AA |
613 | } |
614 | ||
444eb2a4 | 615 | /* |
21440d7e DR |
616 | * always: directly stall for all thp allocations |
617 | * defer: wake kswapd and fail if not immediately available | |
618 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
619 | * fail if not immediately available | |
620 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
621 | * available | |
622 | * never: never stall for any thp allocation | |
444eb2a4 MG |
623 | */ |
624 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) | |
625 | { | |
21440d7e | 626 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 627 | |
21440d7e | 628 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
25160354 | 629 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
21440d7e DR |
630 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
631 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; | |
632 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
633 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
634 | __GFP_KSWAPD_RECLAIM); | |
635 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
636 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
637 | 0); | |
25160354 | 638 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
639 | } |
640 | ||
c4088ebd | 641 | /* Caller must hold page table lock. */ |
d295e341 | 642 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 643 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 644 | struct page *zero_page) |
fc9fe822 KS |
645 | { |
646 | pmd_t entry; | |
7c414164 AM |
647 | if (!pmd_none(*pmd)) |
648 | return false; | |
5918d10a | 649 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 650 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
651 | if (pgtable) |
652 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 653 | set_pmd_at(mm, haddr, pmd, entry); |
e1f56c89 | 654 | atomic_long_inc(&mm->nr_ptes); |
7c414164 | 655 | return true; |
fc9fe822 KS |
656 | } |
657 | ||
82b0f8c3 | 658 | int do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 659 | { |
82b0f8c3 | 660 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 661 | gfp_t gfp; |
71e3aac0 | 662 | struct page *page; |
82b0f8c3 | 663 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 664 | |
128ec037 | 665 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 666 | return VM_FAULT_FALLBACK; |
128ec037 KS |
667 | if (unlikely(anon_vma_prepare(vma))) |
668 | return VM_FAULT_OOM; | |
6d50e60c | 669 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 670 | return VM_FAULT_OOM; |
82b0f8c3 | 671 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 672 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
673 | transparent_hugepage_use_zero_page()) { |
674 | pgtable_t pgtable; | |
675 | struct page *zero_page; | |
676 | bool set; | |
6b251fc9 | 677 | int ret; |
bae473a4 | 678 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
128ec037 | 679 | if (unlikely(!pgtable)) |
ba76149f | 680 | return VM_FAULT_OOM; |
6fcb52a5 | 681 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 682 | if (unlikely(!zero_page)) { |
bae473a4 | 683 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 684 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 685 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 686 | } |
82b0f8c3 | 687 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
688 | ret = 0; |
689 | set = false; | |
82b0f8c3 | 690 | if (pmd_none(*vmf->pmd)) { |
6b251fc9 | 691 | if (userfaultfd_missing(vma)) { |
82b0f8c3 JK |
692 | spin_unlock(vmf->ptl); |
693 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
694 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
695 | } else { | |
bae473a4 | 696 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
697 | haddr, vmf->pmd, zero_page); |
698 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
699 | set = true; |
700 | } | |
701 | } else | |
82b0f8c3 | 702 | spin_unlock(vmf->ptl); |
6fcb52a5 | 703 | if (!set) |
bae473a4 | 704 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 705 | return ret; |
71e3aac0 | 706 | } |
444eb2a4 | 707 | gfp = alloc_hugepage_direct_gfpmask(vma); |
077fcf11 | 708 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
709 | if (unlikely(!page)) { |
710 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 711 | return VM_FAULT_FALLBACK; |
128ec037 | 712 | } |
9a982250 | 713 | prep_transhuge_page(page); |
82b0f8c3 | 714 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
715 | } |
716 | ||
ae18d6dc | 717 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
718 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
719 | pgtable_t pgtable) | |
5cad465d MW |
720 | { |
721 | struct mm_struct *mm = vma->vm_mm; | |
722 | pmd_t entry; | |
723 | spinlock_t *ptl; | |
724 | ||
725 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
726 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
727 | if (pfn_t_devmap(pfn)) | |
728 | entry = pmd_mkdevmap(entry); | |
01871e59 RZ |
729 | if (write) { |
730 | entry = pmd_mkyoung(pmd_mkdirty(entry)); | |
731 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 732 | } |
3b6521f5 OH |
733 | |
734 | if (pgtable) { | |
735 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
736 | atomic_long_inc(&mm->nr_ptes); | |
737 | } | |
738 | ||
01871e59 RZ |
739 | set_pmd_at(mm, addr, pmd, entry); |
740 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 741 | spin_unlock(ptl); |
5cad465d MW |
742 | } |
743 | ||
744 | int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, | |
f25748e3 | 745 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
746 | { |
747 | pgprot_t pgprot = vma->vm_page_prot; | |
3b6521f5 | 748 | pgtable_t pgtable = NULL; |
5cad465d MW |
749 | /* |
750 | * If we had pmd_special, we could avoid all these restrictions, | |
751 | * but we need to be consistent with PTEs and architectures that | |
752 | * can't support a 'special' bit. | |
753 | */ | |
754 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
755 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
756 | (VM_PFNMAP|VM_MIXEDMAP)); | |
757 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
f25748e3 | 758 | BUG_ON(!pfn_t_devmap(pfn)); |
5cad465d MW |
759 | |
760 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
761 | return VM_FAULT_SIGBUS; | |
308a047c | 762 | |
3b6521f5 OH |
763 | if (arch_needs_pgtable_deposit()) { |
764 | pgtable = pte_alloc_one(vma->vm_mm, addr); | |
765 | if (!pgtable) | |
766 | return VM_FAULT_OOM; | |
767 | } | |
768 | ||
308a047c BP |
769 | track_pfn_insert(vma, &pgprot, pfn); |
770 | ||
3b6521f5 | 771 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 772 | return VM_FAULT_NOPAGE; |
5cad465d | 773 | } |
dee41079 | 774 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 775 | |
a00cc7d9 MW |
776 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
777 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) | |
778 | { | |
779 | if (likely(vma->vm_flags & VM_WRITE)) | |
780 | pud = pud_mkwrite(pud); | |
781 | return pud; | |
782 | } | |
783 | ||
784 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
785 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
786 | { | |
787 | struct mm_struct *mm = vma->vm_mm; | |
788 | pud_t entry; | |
789 | spinlock_t *ptl; | |
790 | ||
791 | ptl = pud_lock(mm, pud); | |
792 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); | |
793 | if (pfn_t_devmap(pfn)) | |
794 | entry = pud_mkdevmap(entry); | |
795 | if (write) { | |
796 | entry = pud_mkyoung(pud_mkdirty(entry)); | |
797 | entry = maybe_pud_mkwrite(entry, vma); | |
798 | } | |
799 | set_pud_at(mm, addr, pud, entry); | |
800 | update_mmu_cache_pud(vma, addr, pud); | |
801 | spin_unlock(ptl); | |
802 | } | |
803 | ||
804 | int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
805 | pud_t *pud, pfn_t pfn, bool write) | |
806 | { | |
807 | pgprot_t pgprot = vma->vm_page_prot; | |
808 | /* | |
809 | * If we had pud_special, we could avoid all these restrictions, | |
810 | * but we need to be consistent with PTEs and architectures that | |
811 | * can't support a 'special' bit. | |
812 | */ | |
813 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
814 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
815 | (VM_PFNMAP|VM_MIXEDMAP)); | |
816 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
817 | BUG_ON(!pfn_t_devmap(pfn)); | |
818 | ||
819 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
820 | return VM_FAULT_SIGBUS; | |
821 | ||
822 | track_pfn_insert(vma, &pgprot, pfn); | |
823 | ||
824 | insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); | |
825 | return VM_FAULT_NOPAGE; | |
826 | } | |
827 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
828 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
829 | ||
3565fce3 DW |
830 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
831 | pmd_t *pmd) | |
832 | { | |
833 | pmd_t _pmd; | |
834 | ||
835 | /* | |
836 | * We should set the dirty bit only for FOLL_WRITE but for now | |
837 | * the dirty bit in the pmd is meaningless. And if the dirty | |
838 | * bit will become meaningful and we'll only set it with | |
839 | * FOLL_WRITE, an atomic set_bit will be required on the pmd to | |
840 | * set the young bit, instead of the current set_pmd_at. | |
841 | */ | |
842 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
843 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, | |
844 | pmd, _pmd, 1)) | |
845 | update_mmu_cache_pmd(vma, addr, pmd); | |
846 | } | |
847 | ||
848 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
849 | pmd_t *pmd, int flags) | |
850 | { | |
851 | unsigned long pfn = pmd_pfn(*pmd); | |
852 | struct mm_struct *mm = vma->vm_mm; | |
853 | struct dev_pagemap *pgmap; | |
854 | struct page *page; | |
855 | ||
856 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
857 | ||
8310d48b KF |
858 | /* |
859 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
860 | * not be in this function with `flags & FOLL_COW` set. | |
861 | */ | |
862 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
863 | ||
3565fce3 DW |
864 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
865 | return NULL; | |
866 | ||
867 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
868 | /* pass */; | |
869 | else | |
870 | return NULL; | |
871 | ||
872 | if (flags & FOLL_TOUCH) | |
873 | touch_pmd(vma, addr, pmd); | |
874 | ||
875 | /* | |
876 | * device mapped pages can only be returned if the | |
877 | * caller will manage the page reference count. | |
878 | */ | |
879 | if (!(flags & FOLL_GET)) | |
880 | return ERR_PTR(-EEXIST); | |
881 | ||
882 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
883 | pgmap = get_dev_pagemap(pfn, NULL); | |
884 | if (!pgmap) | |
885 | return ERR_PTR(-EFAULT); | |
886 | page = pfn_to_page(pfn); | |
887 | get_page(page); | |
888 | put_dev_pagemap(pgmap); | |
889 | ||
890 | return page; | |
891 | } | |
892 | ||
71e3aac0 AA |
893 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
894 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
895 | struct vm_area_struct *vma) | |
896 | { | |
c4088ebd | 897 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
898 | struct page *src_page; |
899 | pmd_t pmd; | |
12c9d70b | 900 | pgtable_t pgtable = NULL; |
628d47ce | 901 | int ret = -ENOMEM; |
71e3aac0 | 902 | |
628d47ce KS |
903 | /* Skip if can be re-fill on fault */ |
904 | if (!vma_is_anonymous(vma)) | |
905 | return 0; | |
906 | ||
907 | pgtable = pte_alloc_one(dst_mm, addr); | |
908 | if (unlikely(!pgtable)) | |
909 | goto out; | |
71e3aac0 | 910 | |
c4088ebd KS |
911 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
912 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
913 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
914 | |
915 | ret = -EAGAIN; | |
916 | pmd = *src_pmd; | |
628d47ce | 917 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
918 | pte_free(dst_mm, pgtable); |
919 | goto out_unlock; | |
920 | } | |
fc9fe822 | 921 | /* |
c4088ebd | 922 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
923 | * under splitting since we don't split the page itself, only pmd to |
924 | * a page table. | |
925 | */ | |
926 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 927 | struct page *zero_page; |
97ae1749 KS |
928 | /* |
929 | * get_huge_zero_page() will never allocate a new page here, | |
930 | * since we already have a zero page to copy. It just takes a | |
931 | * reference. | |
932 | */ | |
6fcb52a5 | 933 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 934 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 935 | zero_page); |
fc9fe822 KS |
936 | ret = 0; |
937 | goto out_unlock; | |
938 | } | |
de466bd6 | 939 | |
628d47ce KS |
940 | src_page = pmd_page(pmd); |
941 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
942 | get_page(src_page); | |
943 | page_dup_rmap(src_page, true); | |
944 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
945 | atomic_long_inc(&dst_mm->nr_ptes); | |
946 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); | |
71e3aac0 AA |
947 | |
948 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
949 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
950 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
951 | |
952 | ret = 0; | |
953 | out_unlock: | |
c4088ebd KS |
954 | spin_unlock(src_ptl); |
955 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
956 | out: |
957 | return ret; | |
958 | } | |
959 | ||
a00cc7d9 MW |
960 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
961 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
962 | pud_t *pud) | |
963 | { | |
964 | pud_t _pud; | |
965 | ||
966 | /* | |
967 | * We should set the dirty bit only for FOLL_WRITE but for now | |
968 | * the dirty bit in the pud is meaningless. And if the dirty | |
969 | * bit will become meaningful and we'll only set it with | |
970 | * FOLL_WRITE, an atomic set_bit will be required on the pud to | |
971 | * set the young bit, instead of the current set_pud_at. | |
972 | */ | |
973 | _pud = pud_mkyoung(pud_mkdirty(*pud)); | |
974 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, | |
975 | pud, _pud, 1)) | |
976 | update_mmu_cache_pud(vma, addr, pud); | |
977 | } | |
978 | ||
979 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
980 | pud_t *pud, int flags) | |
981 | { | |
982 | unsigned long pfn = pud_pfn(*pud); | |
983 | struct mm_struct *mm = vma->vm_mm; | |
984 | struct dev_pagemap *pgmap; | |
985 | struct page *page; | |
986 | ||
987 | assert_spin_locked(pud_lockptr(mm, pud)); | |
988 | ||
989 | if (flags & FOLL_WRITE && !pud_write(*pud)) | |
990 | return NULL; | |
991 | ||
992 | if (pud_present(*pud) && pud_devmap(*pud)) | |
993 | /* pass */; | |
994 | else | |
995 | return NULL; | |
996 | ||
997 | if (flags & FOLL_TOUCH) | |
998 | touch_pud(vma, addr, pud); | |
999 | ||
1000 | /* | |
1001 | * device mapped pages can only be returned if the | |
1002 | * caller will manage the page reference count. | |
1003 | */ | |
1004 | if (!(flags & FOLL_GET)) | |
1005 | return ERR_PTR(-EEXIST); | |
1006 | ||
1007 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
1008 | pgmap = get_dev_pagemap(pfn, NULL); | |
1009 | if (!pgmap) | |
1010 | return ERR_PTR(-EFAULT); | |
1011 | page = pfn_to_page(pfn); | |
1012 | get_page(page); | |
1013 | put_dev_pagemap(pgmap); | |
1014 | ||
1015 | return page; | |
1016 | } | |
1017 | ||
1018 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1019 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1020 | struct vm_area_struct *vma) | |
1021 | { | |
1022 | spinlock_t *dst_ptl, *src_ptl; | |
1023 | pud_t pud; | |
1024 | int ret; | |
1025 | ||
1026 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1027 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1028 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1029 | ||
1030 | ret = -EAGAIN; | |
1031 | pud = *src_pud; | |
1032 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1033 | goto out_unlock; | |
1034 | ||
1035 | /* | |
1036 | * When page table lock is held, the huge zero pud should not be | |
1037 | * under splitting since we don't split the page itself, only pud to | |
1038 | * a page table. | |
1039 | */ | |
1040 | if (is_huge_zero_pud(pud)) { | |
1041 | /* No huge zero pud yet */ | |
1042 | } | |
1043 | ||
1044 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1045 | pud = pud_mkold(pud_wrprotect(pud)); | |
1046 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1047 | ||
1048 | ret = 0; | |
1049 | out_unlock: | |
1050 | spin_unlock(src_ptl); | |
1051 | spin_unlock(dst_ptl); | |
1052 | return ret; | |
1053 | } | |
1054 | ||
1055 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1056 | { | |
1057 | pud_t entry; | |
1058 | unsigned long haddr; | |
1059 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1060 | ||
1061 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1062 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1063 | goto unlock; | |
1064 | ||
1065 | entry = pud_mkyoung(orig_pud); | |
1066 | if (write) | |
1067 | entry = pud_mkdirty(entry); | |
1068 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1069 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1070 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1071 | ||
1072 | unlock: | |
1073 | spin_unlock(vmf->ptl); | |
1074 | } | |
1075 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1076 | ||
82b0f8c3 | 1077 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1078 | { |
1079 | pmd_t entry; | |
1080 | unsigned long haddr; | |
20f664aa | 1081 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1082 | |
82b0f8c3 JK |
1083 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1084 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1085 | goto unlock; |
1086 | ||
1087 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1088 | if (write) |
1089 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1090 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1091 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1092 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1093 | |
1094 | unlock: | |
82b0f8c3 | 1095 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1096 | } |
1097 | ||
82b0f8c3 | 1098 | static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, |
bae473a4 | 1099 | struct page *page) |
71e3aac0 | 1100 | { |
82b0f8c3 JK |
1101 | struct vm_area_struct *vma = vmf->vma; |
1102 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1103 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1104 | pgtable_t pgtable; |
1105 | pmd_t _pmd; | |
1106 | int ret = 0, i; | |
1107 | struct page **pages; | |
2ec74c3e SG |
1108 | unsigned long mmun_start; /* For mmu_notifiers */ |
1109 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1110 | |
1111 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1112 | GFP_KERNEL); | |
1113 | if (unlikely(!pages)) { | |
1114 | ret |= VM_FAULT_OOM; | |
1115 | goto out; | |
1116 | } | |
1117 | ||
1118 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1119 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1120 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1121 | if (unlikely(!pages[i] || |
bae473a4 KS |
1122 | mem_cgroup_try_charge(pages[i], vma->vm_mm, |
1123 | GFP_KERNEL, &memcg, false))) { | |
b9bbfbe3 | 1124 | if (pages[i]) |
71e3aac0 | 1125 | put_page(pages[i]); |
b9bbfbe3 | 1126 | while (--i >= 0) { |
00501b53 JW |
1127 | memcg = (void *)page_private(pages[i]); |
1128 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1129 | mem_cgroup_cancel_charge(pages[i], memcg, |
1130 | false); | |
b9bbfbe3 AA |
1131 | put_page(pages[i]); |
1132 | } | |
71e3aac0 AA |
1133 | kfree(pages); |
1134 | ret |= VM_FAULT_OOM; | |
1135 | goto out; | |
1136 | } | |
00501b53 | 1137 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1138 | } |
1139 | ||
1140 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1141 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1142 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1143 | __SetPageUptodate(pages[i]); |
1144 | cond_resched(); | |
1145 | } | |
1146 | ||
2ec74c3e SG |
1147 | mmun_start = haddr; |
1148 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1149 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1150 | |
82b0f8c3 JK |
1151 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1152 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1153 | goto out_free_pages; |
309381fe | 1154 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1155 | |
82b0f8c3 | 1156 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 AA |
1157 | /* leave pmd empty until pte is filled */ |
1158 | ||
82b0f8c3 | 1159 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1160 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1161 | |
1162 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1163 | pte_t entry; |
71e3aac0 AA |
1164 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1165 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1166 | memcg = (void *)page_private(pages[i]); |
1167 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1168 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1169 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1170 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1171 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1172 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1173 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1174 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1175 | } |
1176 | kfree(pages); | |
1177 | ||
71e3aac0 | 1178 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1179 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1180 | page_remove_rmap(page, true); |
82b0f8c3 | 1181 | spin_unlock(vmf->ptl); |
71e3aac0 | 1182 | |
bae473a4 | 1183 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1184 | |
71e3aac0 AA |
1185 | ret |= VM_FAULT_WRITE; |
1186 | put_page(page); | |
1187 | ||
1188 | out: | |
1189 | return ret; | |
1190 | ||
1191 | out_free_pages: | |
82b0f8c3 | 1192 | spin_unlock(vmf->ptl); |
bae473a4 | 1193 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
b9bbfbe3 | 1194 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1195 | memcg = (void *)page_private(pages[i]); |
1196 | set_page_private(pages[i], 0); | |
f627c2f5 | 1197 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1198 | put_page(pages[i]); |
b9bbfbe3 | 1199 | } |
71e3aac0 AA |
1200 | kfree(pages); |
1201 | goto out; | |
1202 | } | |
1203 | ||
82b0f8c3 | 1204 | int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1205 | { |
82b0f8c3 | 1206 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1207 | struct page *page = NULL, *new_page; |
00501b53 | 1208 | struct mem_cgroup *memcg; |
82b0f8c3 | 1209 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2ec74c3e SG |
1210 | unsigned long mmun_start; /* For mmu_notifiers */ |
1211 | unsigned long mmun_end; /* For mmu_notifiers */ | |
3b363692 | 1212 | gfp_t huge_gfp; /* for allocation and charge */ |
bae473a4 | 1213 | int ret = 0; |
71e3aac0 | 1214 | |
82b0f8c3 | 1215 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1216 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1217 | if (is_huge_zero_pmd(orig_pmd)) |
1218 | goto alloc; | |
82b0f8c3 JK |
1219 | spin_lock(vmf->ptl); |
1220 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1221 | goto out_unlock; |
1222 | ||
1223 | page = pmd_page(orig_pmd); | |
309381fe | 1224 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1225 | /* |
1226 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1227 | * part. |
1f25fe20 | 1228 | */ |
6d0a07ed | 1229 | if (page_trans_huge_mapcount(page, NULL) == 1) { |
71e3aac0 AA |
1230 | pmd_t entry; |
1231 | entry = pmd_mkyoung(orig_pmd); | |
1232 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
82b0f8c3 JK |
1233 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1234 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 AA |
1235 | ret |= VM_FAULT_WRITE; |
1236 | goto out_unlock; | |
1237 | } | |
ddc58f27 | 1238 | get_page(page); |
82b0f8c3 | 1239 | spin_unlock(vmf->ptl); |
93b4796d | 1240 | alloc: |
71e3aac0 | 1241 | if (transparent_hugepage_enabled(vma) && |
077fcf11 | 1242 | !transparent_hugepage_debug_cow()) { |
444eb2a4 | 1243 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
3b363692 | 1244 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); |
077fcf11 | 1245 | } else |
71e3aac0 AA |
1246 | new_page = NULL; |
1247 | ||
9a982250 KS |
1248 | if (likely(new_page)) { |
1249 | prep_transhuge_page(new_page); | |
1250 | } else { | |
eecc1e42 | 1251 | if (!page) { |
82b0f8c3 | 1252 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1253 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1254 | } else { |
82b0f8c3 | 1255 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1256 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1257 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1258 | ret |= VM_FAULT_FALLBACK; |
1259 | } | |
ddc58f27 | 1260 | put_page(page); |
93b4796d | 1261 | } |
17766dde | 1262 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1263 | goto out; |
1264 | } | |
1265 | ||
bae473a4 KS |
1266 | if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, |
1267 | huge_gfp, &memcg, true))) { | |
b9bbfbe3 | 1268 | put_page(new_page); |
82b0f8c3 | 1269 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1270 | if (page) |
ddc58f27 | 1271 | put_page(page); |
9845cbbd | 1272 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1273 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1274 | goto out; |
1275 | } | |
1276 | ||
17766dde DR |
1277 | count_vm_event(THP_FAULT_ALLOC); |
1278 | ||
eecc1e42 | 1279 | if (!page) |
93b4796d KS |
1280 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); |
1281 | else | |
1282 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1283 | __SetPageUptodate(new_page); |
1284 | ||
2ec74c3e SG |
1285 | mmun_start = haddr; |
1286 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1287 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1288 | |
82b0f8c3 | 1289 | spin_lock(vmf->ptl); |
93b4796d | 1290 | if (page) |
ddc58f27 | 1291 | put_page(page); |
82b0f8c3 JK |
1292 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1293 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1294 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1295 | put_page(new_page); |
2ec74c3e | 1296 | goto out_mn; |
b9bbfbe3 | 1297 | } else { |
71e3aac0 | 1298 | pmd_t entry; |
3122359a KS |
1299 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1300 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
82b0f8c3 | 1301 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1302 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1303 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1304 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1305 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1306 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1307 | if (!page) { |
bae473a4 | 1308 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1309 | } else { |
309381fe | 1310 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1311 | page_remove_rmap(page, true); |
93b4796d KS |
1312 | put_page(page); |
1313 | } | |
71e3aac0 AA |
1314 | ret |= VM_FAULT_WRITE; |
1315 | } | |
82b0f8c3 | 1316 | spin_unlock(vmf->ptl); |
2ec74c3e | 1317 | out_mn: |
bae473a4 | 1318 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
71e3aac0 AA |
1319 | out: |
1320 | return ret; | |
2ec74c3e | 1321 | out_unlock: |
82b0f8c3 | 1322 | spin_unlock(vmf->ptl); |
2ec74c3e | 1323 | return ret; |
71e3aac0 AA |
1324 | } |
1325 | ||
8310d48b KF |
1326 | /* |
1327 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1328 | * after we've gone through a COW cycle and they are dirty. | |
1329 | */ | |
1330 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1331 | { | |
1332 | return pmd_write(pmd) || | |
1333 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
1334 | } | |
1335 | ||
b676b293 | 1336 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1337 | unsigned long addr, |
1338 | pmd_t *pmd, | |
1339 | unsigned int flags) | |
1340 | { | |
b676b293 | 1341 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1342 | struct page *page = NULL; |
1343 | ||
c4088ebd | 1344 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1345 | |
8310d48b | 1346 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1347 | goto out; |
1348 | ||
85facf25 KS |
1349 | /* Avoid dumping huge zero page */ |
1350 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1351 | return ERR_PTR(-EFAULT); | |
1352 | ||
2b4847e7 | 1353 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1354 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1355 | goto out; |
1356 | ||
71e3aac0 | 1357 | page = pmd_page(*pmd); |
ca120cf6 | 1358 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 DW |
1359 | if (flags & FOLL_TOUCH) |
1360 | touch_pmd(vma, addr, pmd); | |
de60f5f1 | 1361 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1362 | /* |
1363 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1364 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1365 | * | |
9a73f61b KS |
1366 | * For anon THP: |
1367 | * | |
e90309c9 KS |
1368 | * In most cases the pmd is the only mapping of the page as we |
1369 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1370 | * writable private mappings in populate_vma_page_range(). | |
1371 | * | |
1372 | * The only scenario when we have the page shared here is if we | |
1373 | * mlocking read-only mapping shared over fork(). We skip | |
1374 | * mlocking such pages. | |
9a73f61b KS |
1375 | * |
1376 | * For file THP: | |
1377 | * | |
1378 | * We can expect PageDoubleMap() to be stable under page lock: | |
1379 | * for file pages we set it in page_add_file_rmap(), which | |
1380 | * requires page to be locked. | |
e90309c9 | 1381 | */ |
9a73f61b KS |
1382 | |
1383 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1384 | goto skip_mlock; | |
1385 | if (PageDoubleMap(page) || !page->mapping) | |
1386 | goto skip_mlock; | |
1387 | if (!trylock_page(page)) | |
1388 | goto skip_mlock; | |
1389 | lru_add_drain(); | |
1390 | if (page->mapping && !PageDoubleMap(page)) | |
1391 | mlock_vma_page(page); | |
1392 | unlock_page(page); | |
b676b293 | 1393 | } |
9a73f61b | 1394 | skip_mlock: |
71e3aac0 | 1395 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1396 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1397 | if (flags & FOLL_GET) |
ddc58f27 | 1398 | get_page(page); |
71e3aac0 AA |
1399 | |
1400 | out: | |
1401 | return page; | |
1402 | } | |
1403 | ||
d10e63f2 | 1404 | /* NUMA hinting page fault entry point for trans huge pmds */ |
82b0f8c3 | 1405 | int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1406 | { |
82b0f8c3 | 1407 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1408 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1409 | struct page *page; |
82b0f8c3 | 1410 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
8191acbd | 1411 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1412 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1413 | bool page_locked; |
1414 | bool migrated = false; | |
b191f9b1 | 1415 | bool was_writable; |
6688cc05 | 1416 | int flags = 0; |
d10e63f2 | 1417 | |
82b0f8c3 JK |
1418 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1419 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1420 | goto out_unlock; |
1421 | ||
de466bd6 MG |
1422 | /* |
1423 | * If there are potential migrations, wait for completion and retry | |
1424 | * without disrupting NUMA hinting information. Do not relock and | |
1425 | * check_same as the page may no longer be mapped. | |
1426 | */ | |
82b0f8c3 JK |
1427 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1428 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1429 | if (!get_page_unless_zero(page)) |
1430 | goto out_unlock; | |
82b0f8c3 | 1431 | spin_unlock(vmf->ptl); |
5d833062 | 1432 | wait_on_page_locked(page); |
3c226c63 | 1433 | put_page(page); |
de466bd6 MG |
1434 | goto out; |
1435 | } | |
1436 | ||
d10e63f2 | 1437 | page = pmd_page(pmd); |
a1a46184 | 1438 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1439 | page_nid = page_to_nid(page); |
90572890 | 1440 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1441 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1442 | if (page_nid == this_nid) { |
03c5a6e1 | 1443 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1444 | flags |= TNF_FAULT_LOCAL; |
1445 | } | |
4daae3b4 | 1446 | |
bea66fbd | 1447 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1448 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1449 | flags |= TNF_NO_GROUP; |
1450 | ||
ff9042b1 MG |
1451 | /* |
1452 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1453 | * page_table_lock if at all possible | |
1454 | */ | |
b8916634 MG |
1455 | page_locked = trylock_page(page); |
1456 | target_nid = mpol_misplaced(page, vma, haddr); | |
1457 | if (target_nid == -1) { | |
1458 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1459 | if (page_locked) |
b8916634 | 1460 | goto clear_pmdnuma; |
2b4847e7 | 1461 | } |
4daae3b4 | 1462 | |
de466bd6 | 1463 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1464 | if (!page_locked) { |
3c226c63 MR |
1465 | page_nid = -1; |
1466 | if (!get_page_unless_zero(page)) | |
1467 | goto out_unlock; | |
82b0f8c3 | 1468 | spin_unlock(vmf->ptl); |
b8916634 | 1469 | wait_on_page_locked(page); |
3c226c63 | 1470 | put_page(page); |
b8916634 MG |
1471 | goto out; |
1472 | } | |
1473 | ||
2b4847e7 MG |
1474 | /* |
1475 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1476 | * to serialises splits | |
1477 | */ | |
b8916634 | 1478 | get_page(page); |
82b0f8c3 | 1479 | spin_unlock(vmf->ptl); |
b8916634 | 1480 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1481 | |
c69307d5 | 1482 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1483 | spin_lock(vmf->ptl); |
1484 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1485 | unlock_page(page); |
1486 | put_page(page); | |
a54a407f | 1487 | page_nid = -1; |
4daae3b4 | 1488 | goto out_unlock; |
b32967ff | 1489 | } |
ff9042b1 | 1490 | |
c3a489ca MG |
1491 | /* Bail if we fail to protect against THP splits for any reason */ |
1492 | if (unlikely(!anon_vma)) { | |
1493 | put_page(page); | |
1494 | page_nid = -1; | |
1495 | goto clear_pmdnuma; | |
1496 | } | |
1497 | ||
a54a407f MG |
1498 | /* |
1499 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1500 | * and access rights restored. |
a54a407f | 1501 | */ |
82b0f8c3 | 1502 | spin_unlock(vmf->ptl); |
bae473a4 | 1503 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1504 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1505 | if (migrated) { |
1506 | flags |= TNF_MIGRATED; | |
8191acbd | 1507 | page_nid = target_nid; |
074c2381 MG |
1508 | } else |
1509 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1510 | |
8191acbd | 1511 | goto out; |
b32967ff | 1512 | clear_pmdnuma: |
a54a407f | 1513 | BUG_ON(!PageLocked(page)); |
288bc549 | 1514 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1515 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1516 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1517 | if (was_writable) |
1518 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1519 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1520 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1521 | unlock_page(page); |
d10e63f2 | 1522 | out_unlock: |
82b0f8c3 | 1523 | spin_unlock(vmf->ptl); |
b8916634 MG |
1524 | |
1525 | out: | |
1526 | if (anon_vma) | |
1527 | page_unlock_anon_vma_read(anon_vma); | |
1528 | ||
8191acbd | 1529 | if (page_nid != -1) |
82b0f8c3 | 1530 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1531 | flags); |
8191acbd | 1532 | |
d10e63f2 MG |
1533 | return 0; |
1534 | } | |
1535 | ||
319904ad HY |
1536 | /* |
1537 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1538 | * Otherwise, return false. | |
1539 | */ | |
1540 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1541 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1542 | { |
1543 | spinlock_t *ptl; | |
1544 | pmd_t orig_pmd; | |
1545 | struct page *page; | |
1546 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1547 | bool ret = false; |
b8d3c4c3 | 1548 | |
07e32661 AK |
1549 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1550 | ||
b6ec57f4 KS |
1551 | ptl = pmd_trans_huge_lock(pmd, vma); |
1552 | if (!ptl) | |
25eedabe | 1553 | goto out_unlocked; |
b8d3c4c3 MK |
1554 | |
1555 | orig_pmd = *pmd; | |
319904ad | 1556 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1557 | goto out; |
b8d3c4c3 MK |
1558 | |
1559 | page = pmd_page(orig_pmd); | |
1560 | /* | |
1561 | * If other processes are mapping this page, we couldn't discard | |
1562 | * the page unless they all do MADV_FREE so let's skip the page. | |
1563 | */ | |
1564 | if (page_mapcount(page) != 1) | |
1565 | goto out; | |
1566 | ||
1567 | if (!trylock_page(page)) | |
1568 | goto out; | |
1569 | ||
1570 | /* | |
1571 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1572 | * will deactivate only them. | |
1573 | */ | |
1574 | if (next - addr != HPAGE_PMD_SIZE) { | |
1575 | get_page(page); | |
1576 | spin_unlock(ptl); | |
9818b8cd | 1577 | split_huge_page(page); |
b8d3c4c3 MK |
1578 | put_page(page); |
1579 | unlock_page(page); | |
b8d3c4c3 MK |
1580 | goto out_unlocked; |
1581 | } | |
1582 | ||
1583 | if (PageDirty(page)) | |
1584 | ClearPageDirty(page); | |
1585 | unlock_page(page); | |
1586 | ||
b8d3c4c3 | 1587 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1588 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1589 | orig_pmd = pmd_mkold(orig_pmd); |
1590 | orig_pmd = pmd_mkclean(orig_pmd); | |
1591 | ||
1592 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1593 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1594 | } | |
802a3a92 SL |
1595 | |
1596 | mark_page_lazyfree(page); | |
319904ad | 1597 | ret = true; |
b8d3c4c3 MK |
1598 | out: |
1599 | spin_unlock(ptl); | |
1600 | out_unlocked: | |
1601 | return ret; | |
1602 | } | |
1603 | ||
953c66c2 AK |
1604 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1605 | { | |
1606 | pgtable_t pgtable; | |
1607 | ||
1608 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1609 | pte_free(mm, pgtable); | |
1610 | atomic_long_dec(&mm->nr_ptes); | |
1611 | } | |
1612 | ||
71e3aac0 | 1613 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1614 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1615 | { |
da146769 | 1616 | pmd_t orig_pmd; |
bf929152 | 1617 | spinlock_t *ptl; |
71e3aac0 | 1618 | |
07e32661 AK |
1619 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1620 | ||
b6ec57f4 KS |
1621 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1622 | if (!ptl) | |
da146769 KS |
1623 | return 0; |
1624 | /* | |
1625 | * For architectures like ppc64 we look at deposited pgtable | |
1626 | * when calling pmdp_huge_get_and_clear. So do the | |
1627 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1628 | * operations. | |
1629 | */ | |
1630 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1631 | tlb->fullmm); | |
1632 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1633 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1634 | if (arch_needs_pgtable_deposit()) |
1635 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1636 | spin_unlock(ptl); |
1637 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1638 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1639 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1640 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1641 | spin_unlock(ptl); |
c0f2e176 | 1642 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 KS |
1643 | } else { |
1644 | struct page *page = pmd_page(orig_pmd); | |
d281ee61 | 1645 | page_remove_rmap(page, true); |
da146769 | 1646 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
da146769 | 1647 | VM_BUG_ON_PAGE(!PageHead(page), page); |
b5072380 | 1648 | if (PageAnon(page)) { |
c14a6eb4 | 1649 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1650 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1651 | } else { | |
953c66c2 AK |
1652 | if (arch_needs_pgtable_deposit()) |
1653 | zap_deposited_table(tlb->mm, pmd); | |
b5072380 KS |
1654 | add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); |
1655 | } | |
da146769 | 1656 | spin_unlock(ptl); |
e77b0852 | 1657 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); |
025c5b24 | 1658 | } |
da146769 | 1659 | return 1; |
71e3aac0 AA |
1660 | } |
1661 | ||
1dd38b6c AK |
1662 | #ifndef pmd_move_must_withdraw |
1663 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1664 | spinlock_t *old_pmd_ptl, | |
1665 | struct vm_area_struct *vma) | |
1666 | { | |
1667 | /* | |
1668 | * With split pmd lock we also need to move preallocated | |
1669 | * PTE page table if new_pmd is on different PMD page table. | |
1670 | * | |
1671 | * We also don't deposit and withdraw tables for file pages. | |
1672 | */ | |
1673 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1674 | } | |
1675 | #endif | |
1676 | ||
bf8616d5 | 1677 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1678 | unsigned long new_addr, unsigned long old_end, |
5d190420 | 1679 | pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) |
37a1c49a | 1680 | { |
bf929152 | 1681 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1682 | pmd_t pmd; |
37a1c49a | 1683 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1684 | bool force_flush = false; |
37a1c49a AA |
1685 | |
1686 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1687 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1688 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1689 | return false; |
37a1c49a AA |
1690 | |
1691 | /* | |
1692 | * The destination pmd shouldn't be established, free_pgtables() | |
1693 | * should have release it. | |
1694 | */ | |
1695 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1696 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1697 | return false; |
37a1c49a AA |
1698 | } |
1699 | ||
bf929152 KS |
1700 | /* |
1701 | * We don't have to worry about the ordering of src and dst | |
1702 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1703 | */ | |
b6ec57f4 KS |
1704 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1705 | if (old_ptl) { | |
bf929152 KS |
1706 | new_ptl = pmd_lockptr(mm, new_pmd); |
1707 | if (new_ptl != old_ptl) | |
1708 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1709 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
a2ce2666 AL |
1710 | if (pmd_present(pmd) && pmd_dirty(pmd)) |
1711 | force_flush = true; | |
025c5b24 | 1712 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1713 | |
1dd38b6c | 1714 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1715 | pgtable_t pgtable; |
3592806c KS |
1716 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1717 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1718 | } |
b3084f4d AK |
1719 | set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); |
1720 | if (new_ptl != old_ptl) | |
1721 | spin_unlock(new_ptl); | |
5d190420 AL |
1722 | if (force_flush) |
1723 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
1724 | else | |
1725 | *need_flush = true; | |
bf929152 | 1726 | spin_unlock(old_ptl); |
4b471e88 | 1727 | return true; |
37a1c49a | 1728 | } |
4b471e88 | 1729 | return false; |
37a1c49a AA |
1730 | } |
1731 | ||
f123d74a MG |
1732 | /* |
1733 | * Returns | |
1734 | * - 0 if PMD could not be locked | |
1735 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1736 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1737 | */ | |
cd7548ab | 1738 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1739 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1740 | { |
1741 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1742 | spinlock_t *ptl; |
0a85e51d KS |
1743 | pmd_t entry; |
1744 | bool preserve_write; | |
1745 | int ret; | |
cd7548ab | 1746 | |
b6ec57f4 | 1747 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1748 | if (!ptl) |
1749 | return 0; | |
e944fd67 | 1750 | |
0a85e51d KS |
1751 | preserve_write = prot_numa && pmd_write(*pmd); |
1752 | ret = 1; | |
e944fd67 | 1753 | |
0a85e51d KS |
1754 | /* |
1755 | * Avoid trapping faults against the zero page. The read-only | |
1756 | * data is likely to be read-cached on the local CPU and | |
1757 | * local/remote hits to the zero page are not interesting. | |
1758 | */ | |
1759 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1760 | goto unlock; | |
025c5b24 | 1761 | |
0a85e51d KS |
1762 | if (prot_numa && pmd_protnone(*pmd)) |
1763 | goto unlock; | |
1764 | ||
ced10803 KS |
1765 | /* |
1766 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1767 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1768 | * which is also under down_read(mmap_sem): | |
1769 | * | |
1770 | * CPU0: CPU1: | |
1771 | * change_huge_pmd(prot_numa=1) | |
1772 | * pmdp_huge_get_and_clear_notify() | |
1773 | * madvise_dontneed() | |
1774 | * zap_pmd_range() | |
1775 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1776 | * // skip the pmd | |
1777 | * set_pmd_at(); | |
1778 | * // pmd is re-established | |
1779 | * | |
1780 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1781 | * which may break userspace. | |
1782 | * | |
1783 | * pmdp_invalidate() is required to make sure we don't miss | |
1784 | * dirty/young flags set by hardware. | |
1785 | */ | |
1786 | entry = *pmd; | |
1787 | pmdp_invalidate(vma, addr, pmd); | |
1788 | ||
1789 | /* | |
1790 | * Recover dirty/young flags. It relies on pmdp_invalidate to not | |
1791 | * corrupt them. | |
1792 | */ | |
1793 | if (pmd_dirty(*pmd)) | |
1794 | entry = pmd_mkdirty(entry); | |
1795 | if (pmd_young(*pmd)) | |
1796 | entry = pmd_mkyoung(entry); | |
1797 | ||
0a85e51d KS |
1798 | entry = pmd_modify(entry, newprot); |
1799 | if (preserve_write) | |
1800 | entry = pmd_mk_savedwrite(entry); | |
1801 | ret = HPAGE_PMD_NR; | |
1802 | set_pmd_at(mm, addr, pmd, entry); | |
1803 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1804 | unlock: | |
1805 | spin_unlock(ptl); | |
025c5b24 NH |
1806 | return ret; |
1807 | } | |
1808 | ||
1809 | /* | |
8f19b0c0 | 1810 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1811 | * |
8f19b0c0 HY |
1812 | * Note that if it returns page table lock pointer, this routine returns without |
1813 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1814 | */ |
b6ec57f4 | 1815 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1816 | { |
b6ec57f4 KS |
1817 | spinlock_t *ptl; |
1818 | ptl = pmd_lock(vma->vm_mm, pmd); | |
5c7fb56e | 1819 | if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd))) |
b6ec57f4 KS |
1820 | return ptl; |
1821 | spin_unlock(ptl); | |
1822 | return NULL; | |
cd7548ab JW |
1823 | } |
1824 | ||
a00cc7d9 MW |
1825 | /* |
1826 | * Returns true if a given pud maps a thp, false otherwise. | |
1827 | * | |
1828 | * Note that if it returns true, this routine returns without unlocking page | |
1829 | * table lock. So callers must unlock it. | |
1830 | */ | |
1831 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1832 | { | |
1833 | spinlock_t *ptl; | |
1834 | ||
1835 | ptl = pud_lock(vma->vm_mm, pud); | |
1836 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1837 | return ptl; | |
1838 | spin_unlock(ptl); | |
1839 | return NULL; | |
1840 | } | |
1841 | ||
1842 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1843 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1844 | pud_t *pud, unsigned long addr) | |
1845 | { | |
1846 | pud_t orig_pud; | |
1847 | spinlock_t *ptl; | |
1848 | ||
1849 | ptl = __pud_trans_huge_lock(pud, vma); | |
1850 | if (!ptl) | |
1851 | return 0; | |
1852 | /* | |
1853 | * For architectures like ppc64 we look at deposited pgtable | |
1854 | * when calling pudp_huge_get_and_clear. So do the | |
1855 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1856 | * operations. | |
1857 | */ | |
1858 | orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, | |
1859 | tlb->fullmm); | |
1860 | tlb_remove_pud_tlb_entry(tlb, pud, addr); | |
1861 | if (vma_is_dax(vma)) { | |
1862 | spin_unlock(ptl); | |
1863 | /* No zero page support yet */ | |
1864 | } else { | |
1865 | /* No support for anonymous PUD pages yet */ | |
1866 | BUG(); | |
1867 | } | |
1868 | return 1; | |
1869 | } | |
1870 | ||
1871 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1872 | unsigned long haddr) | |
1873 | { | |
1874 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1875 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1876 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1877 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1878 | ||
ce9311cf | 1879 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1880 | |
1881 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1882 | } | |
1883 | ||
1884 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1885 | unsigned long address) | |
1886 | { | |
1887 | spinlock_t *ptl; | |
1888 | struct mm_struct *mm = vma->vm_mm; | |
1889 | unsigned long haddr = address & HPAGE_PUD_MASK; | |
1890 | ||
1891 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PUD_SIZE); | |
1892 | ptl = pud_lock(mm, pud); | |
1893 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) | |
1894 | goto out; | |
1895 | __split_huge_pud_locked(vma, pud, haddr); | |
1896 | ||
1897 | out: | |
1898 | spin_unlock(ptl); | |
1899 | mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PUD_SIZE); | |
1900 | } | |
1901 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1902 | ||
eef1b3ba KS |
1903 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1904 | unsigned long haddr, pmd_t *pmd) | |
1905 | { | |
1906 | struct mm_struct *mm = vma->vm_mm; | |
1907 | pgtable_t pgtable; | |
1908 | pmd_t _pmd; | |
1909 | int i; | |
1910 | ||
1911 | /* leave pmd empty until pte is filled */ | |
1912 | pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
1913 | ||
1914 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1915 | pmd_populate(mm, &_pmd, pgtable); | |
1916 | ||
1917 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1918 | pte_t *pte, entry; | |
1919 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1920 | entry = pte_mkspecial(entry); | |
1921 | pte = pte_offset_map(&_pmd, haddr); | |
1922 | VM_BUG_ON(!pte_none(*pte)); | |
1923 | set_pte_at(mm, haddr, pte, entry); | |
1924 | pte_unmap(pte); | |
1925 | } | |
1926 | smp_wmb(); /* make pte visible before pmd */ | |
1927 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
1928 | } |
1929 | ||
1930 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 1931 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
1932 | { |
1933 | struct mm_struct *mm = vma->vm_mm; | |
1934 | struct page *page; | |
1935 | pgtable_t pgtable; | |
1936 | pmd_t _pmd; | |
804dd150 | 1937 | bool young, write, dirty, soft_dirty; |
2ac015e2 | 1938 | unsigned long addr; |
eef1b3ba KS |
1939 | int i; |
1940 | ||
1941 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
1942 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1943 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
5c7fb56e | 1944 | VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)); |
eef1b3ba KS |
1945 | |
1946 | count_vm_event(THP_SPLIT_PMD); | |
1947 | ||
d21b9e57 KS |
1948 | if (!vma_is_anonymous(vma)) { |
1949 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
1950 | /* |
1951 | * We are going to unmap this huge page. So | |
1952 | * just go ahead and zap it | |
1953 | */ | |
1954 | if (arch_needs_pgtable_deposit()) | |
1955 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
1956 | if (vma_is_dax(vma)) |
1957 | return; | |
1958 | page = pmd_page(_pmd); | |
1959 | if (!PageReferenced(page) && pmd_young(_pmd)) | |
1960 | SetPageReferenced(page); | |
1961 | page_remove_rmap(page, true); | |
1962 | put_page(page); | |
1963 | add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); | |
eef1b3ba KS |
1964 | return; |
1965 | } else if (is_huge_zero_pmd(*pmd)) { | |
1966 | return __split_huge_zero_page_pmd(vma, haddr, pmd); | |
1967 | } | |
1968 | ||
1969 | page = pmd_page(*pmd); | |
1970 | VM_BUG_ON_PAGE(!page_count(page), page); | |
fe896d18 | 1971 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba KS |
1972 | write = pmd_write(*pmd); |
1973 | young = pmd_young(*pmd); | |
b8d3c4c3 | 1974 | dirty = pmd_dirty(*pmd); |
804dd150 | 1975 | soft_dirty = pmd_soft_dirty(*pmd); |
eef1b3ba | 1976 | |
c777e2a8 | 1977 | pmdp_huge_split_prepare(vma, haddr, pmd); |
eef1b3ba KS |
1978 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
1979 | pmd_populate(mm, &_pmd, pgtable); | |
1980 | ||
2ac015e2 | 1981 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
1982 | pte_t entry, *pte; |
1983 | /* | |
1984 | * Note that NUMA hinting access restrictions are not | |
1985 | * transferred to avoid any possibility of altering | |
1986 | * permissions across VMAs. | |
1987 | */ | |
ba988280 KS |
1988 | if (freeze) { |
1989 | swp_entry_t swp_entry; | |
1990 | swp_entry = make_migration_entry(page + i, write); | |
1991 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
1992 | if (soft_dirty) |
1993 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 1994 | } else { |
6d2329f8 | 1995 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 1996 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
1997 | if (!write) |
1998 | entry = pte_wrprotect(entry); | |
1999 | if (!young) | |
2000 | entry = pte_mkold(entry); | |
804dd150 AA |
2001 | if (soft_dirty) |
2002 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2003 | } |
b8d3c4c3 MK |
2004 | if (dirty) |
2005 | SetPageDirty(page + i); | |
2ac015e2 | 2006 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2007 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2008 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2009 | atomic_inc(&page[i]._mapcount); |
2010 | pte_unmap(pte); | |
2011 | } | |
2012 | ||
2013 | /* | |
2014 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2015 | * false-negative page_mapped(). | |
2016 | */ | |
2017 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2018 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2019 | atomic_inc(&page[i]._mapcount); | |
2020 | } | |
2021 | ||
2022 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2023 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2024 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2025 | if (TestClearPageDoubleMap(page)) { |
2026 | /* No need in mapcount reference anymore */ | |
2027 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2028 | atomic_dec(&page[i]._mapcount); | |
2029 | } | |
2030 | } | |
2031 | ||
2032 | smp_wmb(); /* make pte visible before pmd */ | |
e9b61f19 KS |
2033 | /* |
2034 | * Up to this point the pmd is present and huge and userland has the | |
2035 | * whole access to the hugepage during the split (which happens in | |
2036 | * place). If we overwrite the pmd with the not-huge version pointing | |
2037 | * to the pte here (which of course we could if all CPUs were bug | |
2038 | * free), userland could trigger a small page size TLB miss on the | |
2039 | * small sized TLB while the hugepage TLB entry is still established in | |
2040 | * the huge TLB. Some CPU doesn't like that. | |
2041 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2042 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2043 | * only safe if the permission and cache attributes of the two entries | |
2044 | * loaded in the two TLB is identical (which should be the case here). | |
2045 | * But it is generally safer to never allow small and huge TLB entries | |
2046 | * for the same virtual address to be loaded simultaneously. So instead | |
2047 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2048 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2049 | * and pmd_trans_splitting must remain set at all times on the pmd | |
2050 | * until the split is complete for this pmd), then we flush the SMP TLB | |
2051 | * and finally we write the non-huge version of the pmd entry with | |
2052 | * pmd_populate. | |
2053 | */ | |
2054 | pmdp_invalidate(vma, haddr, pmd); | |
eef1b3ba | 2055 | pmd_populate(mm, pmd, pgtable); |
e9b61f19 KS |
2056 | |
2057 | if (freeze) { | |
2ac015e2 | 2058 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2059 | page_remove_rmap(page + i, false); |
2060 | put_page(page + i); | |
2061 | } | |
2062 | } | |
eef1b3ba KS |
2063 | } |
2064 | ||
2065 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2066 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2067 | { |
2068 | spinlock_t *ptl; | |
2069 | struct mm_struct *mm = vma->vm_mm; | |
2070 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
2071 | ||
2072 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
2073 | ptl = pmd_lock(mm, pmd); | |
33f4751e NH |
2074 | |
2075 | /* | |
2076 | * If caller asks to setup a migration entries, we need a page to check | |
2077 | * pmd against. Otherwise we can end up replacing wrong page. | |
2078 | */ | |
2079 | VM_BUG_ON(freeze && !page); | |
2080 | if (page && page != pmd_page(*pmd)) | |
2081 | goto out; | |
2082 | ||
5c7fb56e | 2083 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2084 | page = pmd_page(*pmd); |
5c7fb56e | 2085 | if (PageMlocked(page)) |
5f737714 | 2086 | clear_page_mlock(page); |
5c7fb56e | 2087 | } else if (!pmd_devmap(*pmd)) |
e90309c9 | 2088 | goto out; |
fec89c10 | 2089 | __split_huge_pmd_locked(vma, pmd, haddr, freeze); |
e90309c9 | 2090 | out: |
eef1b3ba KS |
2091 | spin_unlock(ptl); |
2092 | mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
2093 | } | |
2094 | ||
fec89c10 KS |
2095 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2096 | bool freeze, struct page *page) | |
94fcc585 | 2097 | { |
f72e7dcd | 2098 | pgd_t *pgd; |
c2febafc | 2099 | p4d_t *p4d; |
f72e7dcd | 2100 | pud_t *pud; |
94fcc585 AA |
2101 | pmd_t *pmd; |
2102 | ||
78ddc534 | 2103 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2104 | if (!pgd_present(*pgd)) |
2105 | return; | |
2106 | ||
c2febafc KS |
2107 | p4d = p4d_offset(pgd, address); |
2108 | if (!p4d_present(*p4d)) | |
2109 | return; | |
2110 | ||
2111 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2112 | if (!pud_present(*pud)) |
2113 | return; | |
2114 | ||
2115 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2116 | |
33f4751e | 2117 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2118 | } |
2119 | ||
e1b9996b | 2120 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2121 | unsigned long start, |
2122 | unsigned long end, | |
2123 | long adjust_next) | |
2124 | { | |
2125 | /* | |
2126 | * If the new start address isn't hpage aligned and it could | |
2127 | * previously contain an hugepage: check if we need to split | |
2128 | * an huge pmd. | |
2129 | */ | |
2130 | if (start & ~HPAGE_PMD_MASK && | |
2131 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2132 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2133 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2134 | |
2135 | /* | |
2136 | * If the new end address isn't hpage aligned and it could | |
2137 | * previously contain an hugepage: check if we need to split | |
2138 | * an huge pmd. | |
2139 | */ | |
2140 | if (end & ~HPAGE_PMD_MASK && | |
2141 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2142 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2143 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2144 | |
2145 | /* | |
2146 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2147 | * vm_next->vm_start isn't page aligned and it could previously | |
2148 | * contain an hugepage: check if we need to split an huge pmd. | |
2149 | */ | |
2150 | if (adjust_next > 0) { | |
2151 | struct vm_area_struct *next = vma->vm_next; | |
2152 | unsigned long nstart = next->vm_start; | |
2153 | nstart += adjust_next << PAGE_SHIFT; | |
2154 | if (nstart & ~HPAGE_PMD_MASK && | |
2155 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2156 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2157 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2158 | } |
2159 | } | |
e9b61f19 | 2160 | |
fec89c10 | 2161 | static void freeze_page(struct page *page) |
e9b61f19 | 2162 | { |
baa355fd | 2163 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2164 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2165 | bool unmap_success; |
e9b61f19 KS |
2166 | |
2167 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2168 | ||
baa355fd KS |
2169 | if (PageAnon(page)) |
2170 | ttu_flags |= TTU_MIGRATION; | |
2171 | ||
666e5a40 MK |
2172 | unmap_success = try_to_unmap(page, ttu_flags); |
2173 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2174 | } |
2175 | ||
fec89c10 | 2176 | static void unfreeze_page(struct page *page) |
e9b61f19 | 2177 | { |
fec89c10 | 2178 | int i; |
ace71a19 KS |
2179 | if (PageTransHuge(page)) { |
2180 | remove_migration_ptes(page, page, true); | |
2181 | } else { | |
2182 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2183 | remove_migration_ptes(page + i, page + i, true); | |
2184 | } | |
e9b61f19 KS |
2185 | } |
2186 | ||
8df651c7 | 2187 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2188 | struct lruvec *lruvec, struct list_head *list) |
2189 | { | |
e9b61f19 KS |
2190 | struct page *page_tail = head + tail; |
2191 | ||
8df651c7 | 2192 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
fe896d18 | 2193 | VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail); |
e9b61f19 KS |
2194 | |
2195 | /* | |
0139aa7b | 2196 | * tail_page->_refcount is zero and not changing from under us. But |
e9b61f19 | 2197 | * get_page_unless_zero() may be running from under us on the |
baa355fd KS |
2198 | * tail_page. If we used atomic_set() below instead of atomic_inc() or |
2199 | * atomic_add(), we would then run atomic_set() concurrently with | |
e9b61f19 KS |
2200 | * get_page_unless_zero(), and atomic_set() is implemented in C not |
2201 | * using locked ops. spin_unlock on x86 sometime uses locked ops | |
2202 | * because of PPro errata 66, 92, so unless somebody can guarantee | |
2203 | * atomic_set() here would be safe on all archs (and not only on x86), | |
baa355fd | 2204 | * it's safer to use atomic_inc()/atomic_add(). |
e9b61f19 | 2205 | */ |
baa355fd KS |
2206 | if (PageAnon(head)) { |
2207 | page_ref_inc(page_tail); | |
2208 | } else { | |
2209 | /* Additional pin to radix tree */ | |
2210 | page_ref_add(page_tail, 2); | |
2211 | } | |
e9b61f19 KS |
2212 | |
2213 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; | |
2214 | page_tail->flags |= (head->flags & | |
2215 | ((1L << PG_referenced) | | |
2216 | (1L << PG_swapbacked) | | |
2217 | (1L << PG_mlocked) | | |
2218 | (1L << PG_uptodate) | | |
2219 | (1L << PG_active) | | |
2220 | (1L << PG_locked) | | |
b8d3c4c3 MK |
2221 | (1L << PG_unevictable) | |
2222 | (1L << PG_dirty))); | |
e9b61f19 KS |
2223 | |
2224 | /* | |
2225 | * After clearing PageTail the gup refcount can be released. | |
2226 | * Page flags also must be visible before we make the page non-compound. | |
2227 | */ | |
2228 | smp_wmb(); | |
2229 | ||
2230 | clear_compound_head(page_tail); | |
2231 | ||
2232 | if (page_is_young(head)) | |
2233 | set_page_young(page_tail); | |
2234 | if (page_is_idle(head)) | |
2235 | set_page_idle(page_tail); | |
2236 | ||
2237 | /* ->mapping in first tail page is compound_mapcount */ | |
9a982250 | 2238 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
e9b61f19 KS |
2239 | page_tail); |
2240 | page_tail->mapping = head->mapping; | |
2241 | ||
2242 | page_tail->index = head->index + tail; | |
2243 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); | |
2244 | lru_add_page_tail(head, page_tail, lruvec, list); | |
e9b61f19 KS |
2245 | } |
2246 | ||
baa355fd KS |
2247 | static void __split_huge_page(struct page *page, struct list_head *list, |
2248 | unsigned long flags) | |
e9b61f19 KS |
2249 | { |
2250 | struct page *head = compound_head(page); | |
2251 | struct zone *zone = page_zone(head); | |
2252 | struct lruvec *lruvec; | |
baa355fd | 2253 | pgoff_t end = -1; |
8df651c7 | 2254 | int i; |
e9b61f19 | 2255 | |
599d0c95 | 2256 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
2257 | |
2258 | /* complete memcg works before add pages to LRU */ | |
2259 | mem_cgroup_split_huge_fixup(head); | |
2260 | ||
baa355fd KS |
2261 | if (!PageAnon(page)) |
2262 | end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); | |
2263 | ||
2264 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { | |
8df651c7 | 2265 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2266 | /* Some pages can be beyond i_size: drop them from page cache */ |
2267 | if (head[i].index >= end) { | |
2268 | __ClearPageDirty(head + i); | |
2269 | __delete_from_page_cache(head + i, NULL); | |
800d8c63 KS |
2270 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2271 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2272 | put_page(head + i); |
2273 | } | |
2274 | } | |
e9b61f19 KS |
2275 | |
2276 | ClearPageCompound(head); | |
baa355fd KS |
2277 | /* See comment in __split_huge_page_tail() */ |
2278 | if (PageAnon(head)) { | |
2279 | page_ref_inc(head); | |
2280 | } else { | |
2281 | /* Additional pin to radix tree */ | |
2282 | page_ref_add(head, 2); | |
2283 | spin_unlock(&head->mapping->tree_lock); | |
2284 | } | |
2285 | ||
a52633d8 | 2286 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 2287 | |
fec89c10 | 2288 | unfreeze_page(head); |
e9b61f19 KS |
2289 | |
2290 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2291 | struct page *subpage = head + i; | |
2292 | if (subpage == page) | |
2293 | continue; | |
2294 | unlock_page(subpage); | |
2295 | ||
2296 | /* | |
2297 | * Subpages may be freed if there wasn't any mapping | |
2298 | * like if add_to_swap() is running on a lru page that | |
2299 | * had its mapping zapped. And freeing these pages | |
2300 | * requires taking the lru_lock so we do the put_page | |
2301 | * of the tail pages after the split is complete. | |
2302 | */ | |
2303 | put_page(subpage); | |
2304 | } | |
2305 | } | |
2306 | ||
b20ce5e0 KS |
2307 | int total_mapcount(struct page *page) |
2308 | { | |
dd78fedd | 2309 | int i, compound, ret; |
b20ce5e0 KS |
2310 | |
2311 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2312 | ||
2313 | if (likely(!PageCompound(page))) | |
2314 | return atomic_read(&page->_mapcount) + 1; | |
2315 | ||
dd78fedd | 2316 | compound = compound_mapcount(page); |
b20ce5e0 | 2317 | if (PageHuge(page)) |
dd78fedd KS |
2318 | return compound; |
2319 | ret = compound; | |
b20ce5e0 KS |
2320 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2321 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2322 | /* File pages has compound_mapcount included in _mapcount */ |
2323 | if (!PageAnon(page)) | |
2324 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2325 | if (PageDoubleMap(page)) |
2326 | ret -= HPAGE_PMD_NR; | |
2327 | return ret; | |
2328 | } | |
2329 | ||
6d0a07ed AA |
2330 | /* |
2331 | * This calculates accurately how many mappings a transparent hugepage | |
2332 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2333 | * accuracy is primarily needed to know if copy-on-write faults can | |
2334 | * reuse the page and change the mapping to read-write instead of | |
2335 | * copying them. At the same time this returns the total_mapcount too. | |
2336 | * | |
2337 | * The function returns the highest mapcount any one of the subpages | |
2338 | * has. If the return value is one, even if different processes are | |
2339 | * mapping different subpages of the transparent hugepage, they can | |
2340 | * all reuse it, because each process is reusing a different subpage. | |
2341 | * | |
2342 | * The total_mapcount is instead counting all virtual mappings of the | |
2343 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2344 | * caller all mappings belong to the same "mm" and in turn the | |
2345 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2346 | * local one as no other process may be mapping any of the subpages. | |
2347 | * | |
2348 | * It would be more accurate to replace page_mapcount() with | |
2349 | * page_trans_huge_mapcount(), however we only use | |
2350 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2351 | * need full accuracy to avoid breaking page pinning, because | |
2352 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2353 | */ | |
2354 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2355 | { | |
2356 | int i, ret, _total_mapcount, mapcount; | |
2357 | ||
2358 | /* hugetlbfs shouldn't call it */ | |
2359 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2360 | ||
2361 | if (likely(!PageTransCompound(page))) { | |
2362 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2363 | if (total_mapcount) | |
2364 | *total_mapcount = mapcount; | |
2365 | return mapcount; | |
2366 | } | |
2367 | ||
2368 | page = compound_head(page); | |
2369 | ||
2370 | _total_mapcount = ret = 0; | |
2371 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2372 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2373 | ret = max(ret, mapcount); | |
2374 | _total_mapcount += mapcount; | |
2375 | } | |
2376 | if (PageDoubleMap(page)) { | |
2377 | ret -= 1; | |
2378 | _total_mapcount -= HPAGE_PMD_NR; | |
2379 | } | |
2380 | mapcount = compound_mapcount(page); | |
2381 | ret += mapcount; | |
2382 | _total_mapcount += mapcount; | |
2383 | if (total_mapcount) | |
2384 | *total_mapcount = _total_mapcount; | |
2385 | return ret; | |
2386 | } | |
2387 | ||
e9b61f19 KS |
2388 | /* |
2389 | * This function splits huge page into normal pages. @page can point to any | |
2390 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2391 | * | |
2392 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2393 | * The huge page must be locked. | |
2394 | * | |
2395 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2396 | * | |
2397 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2398 | * the hugepage. | |
2399 | * | |
2400 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2401 | * they are not mapped. | |
2402 | * | |
2403 | * Returns 0 if the hugepage is split successfully. | |
2404 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2405 | * us. | |
2406 | */ | |
2407 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2408 | { | |
2409 | struct page *head = compound_head(page); | |
a3d0a918 | 2410 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2411 | struct anon_vma *anon_vma = NULL; |
2412 | struct address_space *mapping = NULL; | |
2413 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2414 | bool mlocked; |
0b9b6fff | 2415 | unsigned long flags; |
e9b61f19 KS |
2416 | |
2417 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2418 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2419 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2420 | ||
baa355fd KS |
2421 | if (PageAnon(head)) { |
2422 | /* | |
2423 | * The caller does not necessarily hold an mmap_sem that would | |
2424 | * prevent the anon_vma disappearing so we first we take a | |
2425 | * reference to it and then lock the anon_vma for write. This | |
2426 | * is similar to page_lock_anon_vma_read except the write lock | |
2427 | * is taken to serialise against parallel split or collapse | |
2428 | * operations. | |
2429 | */ | |
2430 | anon_vma = page_get_anon_vma(head); | |
2431 | if (!anon_vma) { | |
2432 | ret = -EBUSY; | |
2433 | goto out; | |
2434 | } | |
2435 | extra_pins = 0; | |
2436 | mapping = NULL; | |
2437 | anon_vma_lock_write(anon_vma); | |
2438 | } else { | |
2439 | mapping = head->mapping; | |
2440 | ||
2441 | /* Truncated ? */ | |
2442 | if (!mapping) { | |
2443 | ret = -EBUSY; | |
2444 | goto out; | |
2445 | } | |
2446 | ||
2447 | /* Addidional pins from radix tree */ | |
2448 | extra_pins = HPAGE_PMD_NR; | |
2449 | anon_vma = NULL; | |
2450 | i_mmap_lock_read(mapping); | |
e9b61f19 | 2451 | } |
e9b61f19 KS |
2452 | |
2453 | /* | |
2454 | * Racy check if we can split the page, before freeze_page() will | |
2455 | * split PMDs | |
2456 | */ | |
baa355fd | 2457 | if (total_mapcount(head) != page_count(head) - extra_pins - 1) { |
e9b61f19 KS |
2458 | ret = -EBUSY; |
2459 | goto out_unlock; | |
2460 | } | |
2461 | ||
d9654322 | 2462 | mlocked = PageMlocked(page); |
fec89c10 | 2463 | freeze_page(head); |
e9b61f19 KS |
2464 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2465 | ||
d9654322 KS |
2466 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2467 | if (mlocked) | |
2468 | lru_add_drain(); | |
2469 | ||
baa355fd | 2470 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2471 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2472 | |
2473 | if (mapping) { | |
2474 | void **pslot; | |
2475 | ||
2476 | spin_lock(&mapping->tree_lock); | |
2477 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
2478 | page_index(head)); | |
2479 | /* | |
2480 | * Check if the head page is present in radix tree. | |
2481 | * We assume all tail are present too, if head is there. | |
2482 | */ | |
2483 | if (radix_tree_deref_slot_protected(pslot, | |
2484 | &mapping->tree_lock) != head) | |
2485 | goto fail; | |
2486 | } | |
2487 | ||
0139aa7b | 2488 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2489 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2490 | count = page_count(head); |
2491 | mapcount = total_mapcount(head); | |
baa355fd | 2492 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2493 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2494 | pgdata->split_queue_len--; |
9a982250 KS |
2495 | list_del(page_deferred_list(head)); |
2496 | } | |
65c45377 | 2497 | if (mapping) |
11fb9989 | 2498 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd KS |
2499 | spin_unlock(&pgdata->split_queue_lock); |
2500 | __split_huge_page(page, list, flags); | |
e9b61f19 | 2501 | ret = 0; |
e9b61f19 | 2502 | } else { |
baa355fd KS |
2503 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2504 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2505 | mapcount, count); | |
2506 | if (PageTail(page)) | |
2507 | dump_page(head, NULL); | |
2508 | dump_page(page, "total_mapcount(head) > 0"); | |
2509 | BUG(); | |
2510 | } | |
2511 | spin_unlock(&pgdata->split_queue_lock); | |
2512 | fail: if (mapping) | |
2513 | spin_unlock(&mapping->tree_lock); | |
a52633d8 | 2514 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
fec89c10 | 2515 | unfreeze_page(head); |
e9b61f19 KS |
2516 | ret = -EBUSY; |
2517 | } | |
2518 | ||
2519 | out_unlock: | |
baa355fd KS |
2520 | if (anon_vma) { |
2521 | anon_vma_unlock_write(anon_vma); | |
2522 | put_anon_vma(anon_vma); | |
2523 | } | |
2524 | if (mapping) | |
2525 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2526 | out: |
2527 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2528 | return ret; | |
2529 | } | |
9a982250 KS |
2530 | |
2531 | void free_transhuge_page(struct page *page) | |
2532 | { | |
a3d0a918 | 2533 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2534 | unsigned long flags; |
2535 | ||
a3d0a918 | 2536 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2537 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2538 | pgdata->split_queue_len--; |
9a982250 KS |
2539 | list_del(page_deferred_list(page)); |
2540 | } | |
a3d0a918 | 2541 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2542 | free_compound_page(page); |
2543 | } | |
2544 | ||
2545 | void deferred_split_huge_page(struct page *page) | |
2546 | { | |
a3d0a918 | 2547 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2548 | unsigned long flags; |
2549 | ||
2550 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2551 | ||
a3d0a918 | 2552 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2553 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2554 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2555 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2556 | pgdata->split_queue_len++; | |
9a982250 | 2557 | } |
a3d0a918 | 2558 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2559 | } |
2560 | ||
2561 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2562 | struct shrink_control *sc) | |
2563 | { | |
a3d0a918 | 2564 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
cb8d68ec | 2565 | return ACCESS_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2566 | } |
2567 | ||
2568 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2569 | struct shrink_control *sc) | |
2570 | { | |
a3d0a918 | 2571 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2572 | unsigned long flags; |
2573 | LIST_HEAD(list), *pos, *next; | |
2574 | struct page *page; | |
2575 | int split = 0; | |
2576 | ||
a3d0a918 | 2577 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2578 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2579 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2580 | page = list_entry((void *)pos, struct page, mapping); |
2581 | page = compound_head(page); | |
e3ae1953 KS |
2582 | if (get_page_unless_zero(page)) { |
2583 | list_move(page_deferred_list(page), &list); | |
2584 | } else { | |
2585 | /* We lost race with put_compound_page() */ | |
9a982250 | 2586 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2587 | pgdata->split_queue_len--; |
9a982250 | 2588 | } |
e3ae1953 KS |
2589 | if (!--sc->nr_to_scan) |
2590 | break; | |
9a982250 | 2591 | } |
a3d0a918 | 2592 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2593 | |
2594 | list_for_each_safe(pos, next, &list) { | |
2595 | page = list_entry((void *)pos, struct page, mapping); | |
2596 | lock_page(page); | |
2597 | /* split_huge_page() removes page from list on success */ | |
2598 | if (!split_huge_page(page)) | |
2599 | split++; | |
2600 | unlock_page(page); | |
2601 | put_page(page); | |
2602 | } | |
2603 | ||
a3d0a918 KS |
2604 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2605 | list_splice_tail(&list, &pgdata->split_queue); | |
2606 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2607 | |
cb8d68ec KS |
2608 | /* |
2609 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2610 | * This can happen if pages were freed under us. | |
2611 | */ | |
2612 | if (!split && list_empty(&pgdata->split_queue)) | |
2613 | return SHRINK_STOP; | |
2614 | return split; | |
9a982250 KS |
2615 | } |
2616 | ||
2617 | static struct shrinker deferred_split_shrinker = { | |
2618 | .count_objects = deferred_split_count, | |
2619 | .scan_objects = deferred_split_scan, | |
2620 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2621 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2622 | }; |
49071d43 KS |
2623 | |
2624 | #ifdef CONFIG_DEBUG_FS | |
2625 | static int split_huge_pages_set(void *data, u64 val) | |
2626 | { | |
2627 | struct zone *zone; | |
2628 | struct page *page; | |
2629 | unsigned long pfn, max_zone_pfn; | |
2630 | unsigned long total = 0, split = 0; | |
2631 | ||
2632 | if (val != 1) | |
2633 | return -EINVAL; | |
2634 | ||
2635 | for_each_populated_zone(zone) { | |
2636 | max_zone_pfn = zone_end_pfn(zone); | |
2637 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2638 | if (!pfn_valid(pfn)) | |
2639 | continue; | |
2640 | ||
2641 | page = pfn_to_page(pfn); | |
2642 | if (!get_page_unless_zero(page)) | |
2643 | continue; | |
2644 | ||
2645 | if (zone != page_zone(page)) | |
2646 | goto next; | |
2647 | ||
baa355fd | 2648 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2649 | goto next; |
2650 | ||
2651 | total++; | |
2652 | lock_page(page); | |
2653 | if (!split_huge_page(page)) | |
2654 | split++; | |
2655 | unlock_page(page); | |
2656 | next: | |
2657 | put_page(page); | |
2658 | } | |
2659 | } | |
2660 | ||
145bdaa1 | 2661 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2662 | |
2663 | return 0; | |
2664 | } | |
2665 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2666 | "%llu\n"); | |
2667 | ||
2668 | static int __init split_huge_pages_debugfs(void) | |
2669 | { | |
2670 | void *ret; | |
2671 | ||
145bdaa1 | 2672 | ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
49071d43 KS |
2673 | &split_huge_pages_fops); |
2674 | if (!ret) | |
2675 | pr_warn("Failed to create split_huge_pages in debugfs"); | |
2676 | return 0; | |
2677 | } | |
2678 | late_initcall(split_huge_pages_debugfs); | |
2679 | #endif |