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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> |
6b31d595 | 35 | #include <linux/oom.h> |
97ae1749 | 36 | |
71e3aac0 AA |
37 | #include <asm/tlb.h> |
38 | #include <asm/pgalloc.h> | |
39 | #include "internal.h" | |
40 | ||
ba76149f | 41 | /* |
b14d595a MD |
42 | * By default, transparent hugepage support is disabled in order to avoid |
43 | * risking an increased memory footprint for applications that are not | |
44 | * guaranteed to benefit from it. When transparent hugepage support is | |
45 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
46 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
47 | * for all hugepage allocations. | |
ba76149f | 48 | */ |
71e3aac0 | 49 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 50 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 51 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
52 | #endif |
53 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
54 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
55 | #endif | |
444eb2a4 | 56 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
57 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
58 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 59 | |
9a982250 | 60 | static struct shrinker deferred_split_shrinker; |
f000565a | 61 | |
97ae1749 | 62 | static atomic_t huge_zero_refcount; |
56873f43 | 63 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 64 | |
6fcb52a5 | 65 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
66 | { |
67 | struct page *zero_page; | |
68 | retry: | |
69 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 70 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
71 | |
72 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 73 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
74 | if (!zero_page) { |
75 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 76 | return NULL; |
d8a8e1f0 KS |
77 | } |
78 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 79 | preempt_disable(); |
5918d10a | 80 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 81 | preempt_enable(); |
5ddacbe9 | 82 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
83 | goto retry; |
84 | } | |
85 | ||
86 | /* We take additional reference here. It will be put back by shrinker */ | |
87 | atomic_set(&huge_zero_refcount, 2); | |
88 | preempt_enable(); | |
4db0c3c2 | 89 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
90 | } |
91 | ||
6fcb52a5 | 92 | static void put_huge_zero_page(void) |
4a6c1297 | 93 | { |
97ae1749 KS |
94 | /* |
95 | * Counter should never go to zero here. Only shrinker can put | |
96 | * last reference. | |
97 | */ | |
98 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
99 | } |
100 | ||
6fcb52a5 AL |
101 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
102 | { | |
103 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
104 | return READ_ONCE(huge_zero_page); | |
105 | ||
106 | if (!get_huge_zero_page()) | |
107 | return NULL; | |
108 | ||
109 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
110 | put_huge_zero_page(); | |
111 | ||
112 | return READ_ONCE(huge_zero_page); | |
113 | } | |
114 | ||
115 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
116 | { | |
117 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
118 | put_huge_zero_page(); | |
119 | } | |
120 | ||
48896466 GC |
121 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
122 | struct shrink_control *sc) | |
4a6c1297 | 123 | { |
48896466 GC |
124 | /* we can free zero page only if last reference remains */ |
125 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
126 | } | |
97ae1749 | 127 | |
48896466 GC |
128 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
129 | struct shrink_control *sc) | |
130 | { | |
97ae1749 | 131 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
132 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
133 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 134 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 135 | return HPAGE_PMD_NR; |
97ae1749 KS |
136 | } |
137 | ||
138 | return 0; | |
4a6c1297 KS |
139 | } |
140 | ||
97ae1749 | 141 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
142 | .count_objects = shrink_huge_zero_page_count, |
143 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
144 | .seeks = DEFAULT_SEEKS, |
145 | }; | |
146 | ||
71e3aac0 | 147 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
148 | static ssize_t enabled_show(struct kobject *kobj, |
149 | struct kobj_attribute *attr, char *buf) | |
150 | { | |
444eb2a4 MG |
151 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
152 | return sprintf(buf, "[always] madvise never\n"); | |
153 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
154 | return sprintf(buf, "always [madvise] never\n"); | |
155 | else | |
156 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 157 | } |
444eb2a4 | 158 | |
71e3aac0 AA |
159 | static ssize_t enabled_store(struct kobject *kobj, |
160 | struct kobj_attribute *attr, | |
161 | const char *buf, size_t count) | |
162 | { | |
21440d7e | 163 | ssize_t ret = count; |
ba76149f | 164 | |
21440d7e DR |
165 | if (!memcmp("always", buf, |
166 | min(sizeof("always")-1, count))) { | |
167 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
168 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
169 | } else if (!memcmp("madvise", buf, | |
170 | min(sizeof("madvise")-1, count))) { | |
171 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
172 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
173 | } else if (!memcmp("never", buf, | |
174 | min(sizeof("never")-1, count))) { | |
175 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
176 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
177 | } else | |
178 | ret = -EINVAL; | |
ba76149f AA |
179 | |
180 | if (ret > 0) { | |
b46e756f | 181 | int err = start_stop_khugepaged(); |
ba76149f AA |
182 | if (err) |
183 | ret = err; | |
184 | } | |
ba76149f | 185 | return ret; |
71e3aac0 AA |
186 | } |
187 | static struct kobj_attribute enabled_attr = | |
188 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
189 | ||
b46e756f | 190 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
191 | struct kobj_attribute *attr, char *buf, |
192 | enum transparent_hugepage_flag flag) | |
193 | { | |
e27e6151 BH |
194 | return sprintf(buf, "%d\n", |
195 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 196 | } |
e27e6151 | 197 | |
b46e756f | 198 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
199 | struct kobj_attribute *attr, |
200 | const char *buf, size_t count, | |
201 | enum transparent_hugepage_flag flag) | |
202 | { | |
e27e6151 BH |
203 | unsigned long value; |
204 | int ret; | |
205 | ||
206 | ret = kstrtoul(buf, 10, &value); | |
207 | if (ret < 0) | |
208 | return ret; | |
209 | if (value > 1) | |
210 | return -EINVAL; | |
211 | ||
212 | if (value) | |
71e3aac0 | 213 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 214 | else |
71e3aac0 | 215 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
216 | |
217 | return count; | |
218 | } | |
219 | ||
71e3aac0 AA |
220 | static ssize_t defrag_show(struct kobject *kobj, |
221 | struct kobj_attribute *attr, char *buf) | |
222 | { | |
444eb2a4 | 223 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 224 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 225 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
226 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
227 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
228 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
229 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
230 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
231 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 232 | } |
21440d7e | 233 | |
71e3aac0 AA |
234 | static ssize_t defrag_store(struct kobject *kobj, |
235 | struct kobj_attribute *attr, | |
236 | const char *buf, size_t count) | |
237 | { | |
21440d7e DR |
238 | if (!memcmp("always", buf, |
239 | min(sizeof("always")-1, count))) { | |
240 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
241 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
242 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
243 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
244 | } else if (!memcmp("defer+madvise", buf, |
245 | min(sizeof("defer+madvise")-1, count))) { | |
246 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
247 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
248 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
249 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
4fad7fb6 DR |
250 | } else if (!memcmp("defer", buf, |
251 | min(sizeof("defer")-1, count))) { | |
252 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
253 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
254 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
255 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
256 | } else if (!memcmp("madvise", buf, |
257 | min(sizeof("madvise")-1, count))) { | |
258 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
259 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
260 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
261 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
262 | } else if (!memcmp("never", buf, | |
263 | min(sizeof("never")-1, count))) { | |
264 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
265 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
266 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
267 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
268 | } else | |
269 | return -EINVAL; | |
270 | ||
271 | return count; | |
71e3aac0 AA |
272 | } |
273 | static struct kobj_attribute defrag_attr = | |
274 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
275 | ||
79da5407 KS |
276 | static ssize_t use_zero_page_show(struct kobject *kobj, |
277 | struct kobj_attribute *attr, char *buf) | |
278 | { | |
b46e756f | 279 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
280 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
281 | } | |
282 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
283 | struct kobj_attribute *attr, const char *buf, size_t count) | |
284 | { | |
b46e756f | 285 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
286 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
287 | } | |
288 | static struct kobj_attribute use_zero_page_attr = | |
289 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
290 | |
291 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
292 | struct kobj_attribute *attr, char *buf) | |
293 | { | |
294 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
295 | } | |
296 | static struct kobj_attribute hpage_pmd_size_attr = | |
297 | __ATTR_RO(hpage_pmd_size); | |
298 | ||
71e3aac0 AA |
299 | #ifdef CONFIG_DEBUG_VM |
300 | static ssize_t debug_cow_show(struct kobject *kobj, | |
301 | struct kobj_attribute *attr, char *buf) | |
302 | { | |
b46e756f | 303 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
304 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
305 | } | |
306 | static ssize_t debug_cow_store(struct kobject *kobj, | |
307 | struct kobj_attribute *attr, | |
308 | const char *buf, size_t count) | |
309 | { | |
b46e756f | 310 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
311 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
312 | } | |
313 | static struct kobj_attribute debug_cow_attr = | |
314 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
315 | #endif /* CONFIG_DEBUG_VM */ | |
316 | ||
317 | static struct attribute *hugepage_attr[] = { | |
318 | &enabled_attr.attr, | |
319 | &defrag_attr.attr, | |
79da5407 | 320 | &use_zero_page_attr.attr, |
49920d28 | 321 | &hpage_pmd_size_attr.attr, |
e496cf3d | 322 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
323 | &shmem_enabled_attr.attr, |
324 | #endif | |
71e3aac0 AA |
325 | #ifdef CONFIG_DEBUG_VM |
326 | &debug_cow_attr.attr, | |
327 | #endif | |
328 | NULL, | |
329 | }; | |
330 | ||
8aa95a21 | 331 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 332 | .attrs = hugepage_attr, |
ba76149f AA |
333 | }; |
334 | ||
569e5590 | 335 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 336 | { |
71e3aac0 AA |
337 | int err; |
338 | ||
569e5590 SL |
339 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
340 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 341 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 342 | return -ENOMEM; |
ba76149f AA |
343 | } |
344 | ||
569e5590 | 345 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 346 | if (err) { |
ae3a8c1c | 347 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 348 | goto delete_obj; |
ba76149f AA |
349 | } |
350 | ||
569e5590 | 351 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 352 | if (err) { |
ae3a8c1c | 353 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 354 | goto remove_hp_group; |
ba76149f | 355 | } |
569e5590 SL |
356 | |
357 | return 0; | |
358 | ||
359 | remove_hp_group: | |
360 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
361 | delete_obj: | |
362 | kobject_put(*hugepage_kobj); | |
363 | return err; | |
364 | } | |
365 | ||
366 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
367 | { | |
368 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
369 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
370 | kobject_put(hugepage_kobj); | |
371 | } | |
372 | #else | |
373 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
374 | { | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
379 | { | |
380 | } | |
381 | #endif /* CONFIG_SYSFS */ | |
382 | ||
383 | static int __init hugepage_init(void) | |
384 | { | |
385 | int err; | |
386 | struct kobject *hugepage_kobj; | |
387 | ||
388 | if (!has_transparent_hugepage()) { | |
389 | transparent_hugepage_flags = 0; | |
390 | return -EINVAL; | |
391 | } | |
392 | ||
ff20c2e0 KS |
393 | /* |
394 | * hugepages can't be allocated by the buddy allocator | |
395 | */ | |
396 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
397 | /* | |
398 | * we use page->mapping and page->index in second tail page | |
399 | * as list_head: assuming THP order >= 2 | |
400 | */ | |
401 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
402 | ||
569e5590 SL |
403 | err = hugepage_init_sysfs(&hugepage_kobj); |
404 | if (err) | |
65ebb64f | 405 | goto err_sysfs; |
ba76149f | 406 | |
b46e756f | 407 | err = khugepaged_init(); |
ba76149f | 408 | if (err) |
65ebb64f | 409 | goto err_slab; |
ba76149f | 410 | |
65ebb64f KS |
411 | err = register_shrinker(&huge_zero_page_shrinker); |
412 | if (err) | |
413 | goto err_hzp_shrinker; | |
9a982250 KS |
414 | err = register_shrinker(&deferred_split_shrinker); |
415 | if (err) | |
416 | goto err_split_shrinker; | |
97ae1749 | 417 | |
97562cd2 RR |
418 | /* |
419 | * By default disable transparent hugepages on smaller systems, | |
420 | * where the extra memory used could hurt more than TLB overhead | |
421 | * is likely to save. The admin can still enable it through /sys. | |
422 | */ | |
ca79b0c2 | 423 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 424 | transparent_hugepage_flags = 0; |
79553da2 KS |
425 | return 0; |
426 | } | |
97562cd2 | 427 | |
79553da2 | 428 | err = start_stop_khugepaged(); |
65ebb64f KS |
429 | if (err) |
430 | goto err_khugepaged; | |
ba76149f | 431 | |
569e5590 | 432 | return 0; |
65ebb64f | 433 | err_khugepaged: |
9a982250 KS |
434 | unregister_shrinker(&deferred_split_shrinker); |
435 | err_split_shrinker: | |
65ebb64f KS |
436 | unregister_shrinker(&huge_zero_page_shrinker); |
437 | err_hzp_shrinker: | |
b46e756f | 438 | khugepaged_destroy(); |
65ebb64f | 439 | err_slab: |
569e5590 | 440 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 441 | err_sysfs: |
ba76149f | 442 | return err; |
71e3aac0 | 443 | } |
a64fb3cd | 444 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
445 | |
446 | static int __init setup_transparent_hugepage(char *str) | |
447 | { | |
448 | int ret = 0; | |
449 | if (!str) | |
450 | goto out; | |
451 | if (!strcmp(str, "always")) { | |
452 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
453 | &transparent_hugepage_flags); | |
454 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
455 | &transparent_hugepage_flags); | |
456 | ret = 1; | |
457 | } else if (!strcmp(str, "madvise")) { | |
458 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
459 | &transparent_hugepage_flags); | |
460 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
461 | &transparent_hugepage_flags); | |
462 | ret = 1; | |
463 | } else if (!strcmp(str, "never")) { | |
464 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
465 | &transparent_hugepage_flags); | |
466 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
467 | &transparent_hugepage_flags); | |
468 | ret = 1; | |
469 | } | |
470 | out: | |
471 | if (!ret) | |
ae3a8c1c | 472 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
473 | return ret; |
474 | } | |
475 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
476 | ||
f55e1014 | 477 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 478 | { |
f55e1014 | 479 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
480 | pmd = pmd_mkwrite(pmd); |
481 | return pmd; | |
482 | } | |
483 | ||
9a982250 KS |
484 | static inline struct list_head *page_deferred_list(struct page *page) |
485 | { | |
fa3015b7 MW |
486 | /* ->lru in the tail pages is occupied by compound_head. */ |
487 | return &page[2].deferred_list; | |
9a982250 KS |
488 | } |
489 | ||
490 | void prep_transhuge_page(struct page *page) | |
491 | { | |
492 | /* | |
493 | * we use page->mapping and page->indexlru in second tail page | |
494 | * as list_head: assuming THP order >= 2 | |
495 | */ | |
9a982250 KS |
496 | |
497 | INIT_LIST_HEAD(page_deferred_list(page)); | |
498 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
499 | } | |
500 | ||
74d2fad1 TK |
501 | unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
502 | loff_t off, unsigned long flags, unsigned long size) | |
503 | { | |
504 | unsigned long addr; | |
505 | loff_t off_end = off + len; | |
506 | loff_t off_align = round_up(off, size); | |
507 | unsigned long len_pad; | |
508 | ||
509 | if (off_end <= off_align || (off_end - off_align) < size) | |
510 | return 0; | |
511 | ||
512 | len_pad = len + size; | |
513 | if (len_pad < len || (off + len_pad) < off) | |
514 | return 0; | |
515 | ||
516 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
517 | off >> PAGE_SHIFT, flags); | |
518 | if (IS_ERR_VALUE(addr)) | |
519 | return 0; | |
520 | ||
521 | addr += (off - addr) & (size - 1); | |
522 | return addr; | |
523 | } | |
524 | ||
525 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
526 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
527 | { | |
528 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
529 | ||
530 | if (addr) | |
531 | goto out; | |
532 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
533 | goto out; | |
534 | ||
535 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
536 | if (addr) | |
537 | return addr; | |
538 | ||
539 | out: | |
540 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
541 | } | |
542 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
543 | ||
2b740303 SJ |
544 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
545 | struct page *page, gfp_t gfp) | |
71e3aac0 | 546 | { |
82b0f8c3 | 547 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 548 | struct mem_cgroup *memcg; |
71e3aac0 | 549 | pgtable_t pgtable; |
82b0f8c3 | 550 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 551 | vm_fault_t ret = 0; |
71e3aac0 | 552 | |
309381fe | 553 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 554 | |
2cf85583 | 555 | if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
556 | put_page(page); |
557 | count_vm_event(THP_FAULT_FALLBACK); | |
558 | return VM_FAULT_FALLBACK; | |
559 | } | |
00501b53 | 560 | |
bae473a4 | 561 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
00501b53 | 562 | if (unlikely(!pgtable)) { |
6b31d595 MH |
563 | ret = VM_FAULT_OOM; |
564 | goto release; | |
00501b53 | 565 | } |
71e3aac0 | 566 | |
c79b57e4 | 567 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
568 | /* |
569 | * The memory barrier inside __SetPageUptodate makes sure that | |
570 | * clear_huge_page writes become visible before the set_pmd_at() | |
571 | * write. | |
572 | */ | |
71e3aac0 AA |
573 | __SetPageUptodate(page); |
574 | ||
82b0f8c3 JK |
575 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
576 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 577 | goto unlock_release; |
71e3aac0 AA |
578 | } else { |
579 | pmd_t entry; | |
6b251fc9 | 580 | |
6b31d595 MH |
581 | ret = check_stable_address_space(vma->vm_mm); |
582 | if (ret) | |
583 | goto unlock_release; | |
584 | ||
6b251fc9 AA |
585 | /* Deliver the page fault to userland */ |
586 | if (userfaultfd_missing(vma)) { | |
2b740303 | 587 | vm_fault_t ret2; |
6b251fc9 | 588 | |
82b0f8c3 | 589 | spin_unlock(vmf->ptl); |
f627c2f5 | 590 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 591 | put_page(page); |
bae473a4 | 592 | pte_free(vma->vm_mm, pgtable); |
2b740303 SJ |
593 | ret2 = handle_userfault(vmf, VM_UFFD_MISSING); |
594 | VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); | |
595 | return ret2; | |
6b251fc9 AA |
596 | } |
597 | ||
3122359a | 598 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 599 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 600 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 601 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 602 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
603 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
604 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 605 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 606 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 607 | spin_unlock(vmf->ptl); |
6b251fc9 | 608 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 AA |
609 | } |
610 | ||
aa2e878e | 611 | return 0; |
6b31d595 MH |
612 | unlock_release: |
613 | spin_unlock(vmf->ptl); | |
614 | release: | |
615 | if (pgtable) | |
616 | pte_free(vma->vm_mm, pgtable); | |
617 | mem_cgroup_cancel_charge(page, memcg, true); | |
618 | put_page(page); | |
619 | return ret; | |
620 | ||
71e3aac0 AA |
621 | } |
622 | ||
444eb2a4 | 623 | /* |
21440d7e DR |
624 | * always: directly stall for all thp allocations |
625 | * defer: wake kswapd and fail if not immediately available | |
626 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
627 | * fail if not immediately available | |
628 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
629 | * available | |
630 | * never: never stall for any thp allocation | |
444eb2a4 | 631 | */ |
356ff8a9 | 632 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) |
444eb2a4 | 633 | { |
21440d7e | 634 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 635 | |
2f0799a0 | 636 | /* Always do synchronous compaction */ |
21440d7e | 637 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 638 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
2f0799a0 DR |
639 | |
640 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 641 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 642 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
2f0799a0 DR |
643 | |
644 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 645 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
646 | return GFP_TRANSHUGE_LIGHT | |
647 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
648 | __GFP_KSWAPD_RECLAIM); | |
2f0799a0 DR |
649 | |
650 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 651 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
652 | return GFP_TRANSHUGE_LIGHT | |
653 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
2f0799a0 | 654 | |
356ff8a9 | 655 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
656 | } |
657 | ||
c4088ebd | 658 | /* Caller must hold page table lock. */ |
d295e341 | 659 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 660 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 661 | struct page *zero_page) |
fc9fe822 KS |
662 | { |
663 | pmd_t entry; | |
7c414164 AM |
664 | if (!pmd_none(*pmd)) |
665 | return false; | |
5918d10a | 666 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 667 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
668 | if (pgtable) |
669 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 670 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 671 | mm_inc_nr_ptes(mm); |
7c414164 | 672 | return true; |
fc9fe822 KS |
673 | } |
674 | ||
2b740303 | 675 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 676 | { |
82b0f8c3 | 677 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 678 | gfp_t gfp; |
71e3aac0 | 679 | struct page *page; |
82b0f8c3 | 680 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 681 | |
128ec037 | 682 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 683 | return VM_FAULT_FALLBACK; |
128ec037 KS |
684 | if (unlikely(anon_vma_prepare(vma))) |
685 | return VM_FAULT_OOM; | |
6d50e60c | 686 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 687 | return VM_FAULT_OOM; |
82b0f8c3 | 688 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 689 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
690 | transparent_hugepage_use_zero_page()) { |
691 | pgtable_t pgtable; | |
692 | struct page *zero_page; | |
693 | bool set; | |
2b740303 | 694 | vm_fault_t ret; |
bae473a4 | 695 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
128ec037 | 696 | if (unlikely(!pgtable)) |
ba76149f | 697 | return VM_FAULT_OOM; |
6fcb52a5 | 698 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 699 | if (unlikely(!zero_page)) { |
bae473a4 | 700 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 701 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 702 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 703 | } |
82b0f8c3 | 704 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
705 | ret = 0; |
706 | set = false; | |
82b0f8c3 | 707 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
708 | ret = check_stable_address_space(vma->vm_mm); |
709 | if (ret) { | |
710 | spin_unlock(vmf->ptl); | |
711 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
712 | spin_unlock(vmf->ptl); |
713 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
714 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
715 | } else { | |
bae473a4 | 716 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
717 | haddr, vmf->pmd, zero_page); |
718 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
719 | set = true; |
720 | } | |
721 | } else | |
82b0f8c3 | 722 | spin_unlock(vmf->ptl); |
6fcb52a5 | 723 | if (!set) |
bae473a4 | 724 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 725 | return ret; |
71e3aac0 | 726 | } |
356ff8a9 DR |
727 | gfp = alloc_hugepage_direct_gfpmask(vma); |
728 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); | |
128ec037 KS |
729 | if (unlikely(!page)) { |
730 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 731 | return VM_FAULT_FALLBACK; |
128ec037 | 732 | } |
9a982250 | 733 | prep_transhuge_page(page); |
82b0f8c3 | 734 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
735 | } |
736 | ||
ae18d6dc | 737 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
738 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
739 | pgtable_t pgtable) | |
5cad465d MW |
740 | { |
741 | struct mm_struct *mm = vma->vm_mm; | |
742 | pmd_t entry; | |
743 | spinlock_t *ptl; | |
744 | ||
745 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
746 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
747 | if (pfn_t_devmap(pfn)) | |
748 | entry = pmd_mkdevmap(entry); | |
01871e59 | 749 | if (write) { |
f55e1014 LT |
750 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
751 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 752 | } |
3b6521f5 OH |
753 | |
754 | if (pgtable) { | |
755 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 756 | mm_inc_nr_ptes(mm); |
3b6521f5 OH |
757 | } |
758 | ||
01871e59 RZ |
759 | set_pmd_at(mm, addr, pmd, entry); |
760 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 761 | spin_unlock(ptl); |
5cad465d MW |
762 | } |
763 | ||
226ab561 | 764 | vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
f25748e3 | 765 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
766 | { |
767 | pgprot_t pgprot = vma->vm_page_prot; | |
3b6521f5 | 768 | pgtable_t pgtable = NULL; |
5cad465d MW |
769 | /* |
770 | * If we had pmd_special, we could avoid all these restrictions, | |
771 | * but we need to be consistent with PTEs and architectures that | |
772 | * can't support a 'special' bit. | |
773 | */ | |
e1fb4a08 DJ |
774 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
775 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
776 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
777 | (VM_PFNMAP|VM_MIXEDMAP)); | |
778 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
779 | |
780 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
781 | return VM_FAULT_SIGBUS; | |
308a047c | 782 | |
3b6521f5 OH |
783 | if (arch_needs_pgtable_deposit()) { |
784 | pgtable = pte_alloc_one(vma->vm_mm, addr); | |
785 | if (!pgtable) | |
786 | return VM_FAULT_OOM; | |
787 | } | |
788 | ||
308a047c BP |
789 | track_pfn_insert(vma, &pgprot, pfn); |
790 | ||
3b6521f5 | 791 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 792 | return VM_FAULT_NOPAGE; |
5cad465d | 793 | } |
dee41079 | 794 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 795 | |
a00cc7d9 | 796 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 797 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 798 | { |
f55e1014 | 799 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
800 | pud = pud_mkwrite(pud); |
801 | return pud; | |
802 | } | |
803 | ||
804 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
805 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
806 | { | |
807 | struct mm_struct *mm = vma->vm_mm; | |
808 | pud_t entry; | |
809 | spinlock_t *ptl; | |
810 | ||
811 | ptl = pud_lock(mm, pud); | |
812 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); | |
813 | if (pfn_t_devmap(pfn)) | |
814 | entry = pud_mkdevmap(entry); | |
815 | if (write) { | |
f55e1014 LT |
816 | entry = pud_mkyoung(pud_mkdirty(entry)); |
817 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
818 | } |
819 | set_pud_at(mm, addr, pud, entry); | |
820 | update_mmu_cache_pud(vma, addr, pud); | |
821 | spin_unlock(ptl); | |
822 | } | |
823 | ||
226ab561 | 824 | vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, |
a00cc7d9 MW |
825 | pud_t *pud, pfn_t pfn, bool write) |
826 | { | |
827 | pgprot_t pgprot = vma->vm_page_prot; | |
828 | /* | |
829 | * If we had pud_special, we could avoid all these restrictions, | |
830 | * but we need to be consistent with PTEs and architectures that | |
831 | * can't support a 'special' bit. | |
832 | */ | |
62ec0d8c DJ |
833 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
834 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
835 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
836 | (VM_PFNMAP|VM_MIXEDMAP)); | |
837 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
838 | |
839 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
840 | return VM_FAULT_SIGBUS; | |
841 | ||
842 | track_pfn_insert(vma, &pgprot, pfn); | |
843 | ||
844 | insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); | |
845 | return VM_FAULT_NOPAGE; | |
846 | } | |
847 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
848 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
849 | ||
3565fce3 | 850 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 851 | pmd_t *pmd, int flags) |
3565fce3 DW |
852 | { |
853 | pmd_t _pmd; | |
854 | ||
a8f97366 KS |
855 | _pmd = pmd_mkyoung(*pmd); |
856 | if (flags & FOLL_WRITE) | |
857 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 858 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 859 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
860 | update_mmu_cache_pmd(vma, addr, pmd); |
861 | } | |
862 | ||
863 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 864 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
865 | { |
866 | unsigned long pfn = pmd_pfn(*pmd); | |
867 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
868 | struct page *page; |
869 | ||
870 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
871 | ||
8310d48b KF |
872 | /* |
873 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
874 | * not be in this function with `flags & FOLL_COW` set. | |
875 | */ | |
876 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
877 | ||
f6f37321 | 878 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
879 | return NULL; |
880 | ||
881 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
882 | /* pass */; | |
883 | else | |
884 | return NULL; | |
885 | ||
886 | if (flags & FOLL_TOUCH) | |
a8f97366 | 887 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
888 | |
889 | /* | |
890 | * device mapped pages can only be returned if the | |
891 | * caller will manage the page reference count. | |
892 | */ | |
893 | if (!(flags & FOLL_GET)) | |
894 | return ERR_PTR(-EEXIST); | |
895 | ||
896 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
897 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
898 | if (!*pgmap) | |
3565fce3 DW |
899 | return ERR_PTR(-EFAULT); |
900 | page = pfn_to_page(pfn); | |
901 | get_page(page); | |
3565fce3 DW |
902 | |
903 | return page; | |
904 | } | |
905 | ||
71e3aac0 AA |
906 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
907 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
908 | struct vm_area_struct *vma) | |
909 | { | |
c4088ebd | 910 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
911 | struct page *src_page; |
912 | pmd_t pmd; | |
12c9d70b | 913 | pgtable_t pgtable = NULL; |
628d47ce | 914 | int ret = -ENOMEM; |
71e3aac0 | 915 | |
628d47ce KS |
916 | /* Skip if can be re-fill on fault */ |
917 | if (!vma_is_anonymous(vma)) | |
918 | return 0; | |
919 | ||
920 | pgtable = pte_alloc_one(dst_mm, addr); | |
921 | if (unlikely(!pgtable)) | |
922 | goto out; | |
71e3aac0 | 923 | |
c4088ebd KS |
924 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
925 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
926 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
927 | |
928 | ret = -EAGAIN; | |
929 | pmd = *src_pmd; | |
84c3fc4e ZY |
930 | |
931 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
932 | if (unlikely(is_swap_pmd(pmd))) { | |
933 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
934 | ||
935 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
936 | if (is_write_migration_entry(entry)) { | |
937 | make_migration_entry_read(&entry); | |
938 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
939 | if (pmd_swp_soft_dirty(*src_pmd)) |
940 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
941 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
942 | } | |
dd8a67f9 | 943 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 944 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 945 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
946 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
947 | ret = 0; | |
948 | goto out_unlock; | |
949 | } | |
950 | #endif | |
951 | ||
628d47ce | 952 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
953 | pte_free(dst_mm, pgtable); |
954 | goto out_unlock; | |
955 | } | |
fc9fe822 | 956 | /* |
c4088ebd | 957 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
958 | * under splitting since we don't split the page itself, only pmd to |
959 | * a page table. | |
960 | */ | |
961 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 962 | struct page *zero_page; |
97ae1749 KS |
963 | /* |
964 | * get_huge_zero_page() will never allocate a new page here, | |
965 | * since we already have a zero page to copy. It just takes a | |
966 | * reference. | |
967 | */ | |
6fcb52a5 | 968 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 969 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 970 | zero_page); |
fc9fe822 KS |
971 | ret = 0; |
972 | goto out_unlock; | |
973 | } | |
de466bd6 | 974 | |
628d47ce KS |
975 | src_page = pmd_page(pmd); |
976 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
977 | get_page(src_page); | |
978 | page_dup_rmap(src_page, true); | |
979 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 980 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 981 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
982 | |
983 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
984 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
985 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
986 | |
987 | ret = 0; | |
988 | out_unlock: | |
c4088ebd KS |
989 | spin_unlock(src_ptl); |
990 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
991 | out: |
992 | return ret; | |
993 | } | |
994 | ||
a00cc7d9 MW |
995 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
996 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 997 | pud_t *pud, int flags) |
a00cc7d9 MW |
998 | { |
999 | pud_t _pud; | |
1000 | ||
a8f97366 KS |
1001 | _pud = pud_mkyoung(*pud); |
1002 | if (flags & FOLL_WRITE) | |
1003 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1004 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1005 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1006 | update_mmu_cache_pud(vma, addr, pud); |
1007 | } | |
1008 | ||
1009 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1010 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1011 | { |
1012 | unsigned long pfn = pud_pfn(*pud); | |
1013 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1014 | struct page *page; |
1015 | ||
1016 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1017 | ||
f6f37321 | 1018 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1019 | return NULL; |
1020 | ||
1021 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1022 | /* pass */; | |
1023 | else | |
1024 | return NULL; | |
1025 | ||
1026 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1027 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1028 | |
1029 | /* | |
1030 | * device mapped pages can only be returned if the | |
1031 | * caller will manage the page reference count. | |
1032 | */ | |
1033 | if (!(flags & FOLL_GET)) | |
1034 | return ERR_PTR(-EEXIST); | |
1035 | ||
1036 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1037 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1038 | if (!*pgmap) | |
a00cc7d9 MW |
1039 | return ERR_PTR(-EFAULT); |
1040 | page = pfn_to_page(pfn); | |
1041 | get_page(page); | |
a00cc7d9 MW |
1042 | |
1043 | return page; | |
1044 | } | |
1045 | ||
1046 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1047 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1048 | struct vm_area_struct *vma) | |
1049 | { | |
1050 | spinlock_t *dst_ptl, *src_ptl; | |
1051 | pud_t pud; | |
1052 | int ret; | |
1053 | ||
1054 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1055 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1056 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1057 | ||
1058 | ret = -EAGAIN; | |
1059 | pud = *src_pud; | |
1060 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1061 | goto out_unlock; | |
1062 | ||
1063 | /* | |
1064 | * When page table lock is held, the huge zero pud should not be | |
1065 | * under splitting since we don't split the page itself, only pud to | |
1066 | * a page table. | |
1067 | */ | |
1068 | if (is_huge_zero_pud(pud)) { | |
1069 | /* No huge zero pud yet */ | |
1070 | } | |
1071 | ||
1072 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1073 | pud = pud_mkold(pud_wrprotect(pud)); | |
1074 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1075 | ||
1076 | ret = 0; | |
1077 | out_unlock: | |
1078 | spin_unlock(src_ptl); | |
1079 | spin_unlock(dst_ptl); | |
1080 | return ret; | |
1081 | } | |
1082 | ||
1083 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1084 | { | |
1085 | pud_t entry; | |
1086 | unsigned long haddr; | |
1087 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1088 | ||
1089 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1090 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1091 | goto unlock; | |
1092 | ||
1093 | entry = pud_mkyoung(orig_pud); | |
1094 | if (write) | |
1095 | entry = pud_mkdirty(entry); | |
1096 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1097 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1098 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1099 | ||
1100 | unlock: | |
1101 | spin_unlock(vmf->ptl); | |
1102 | } | |
1103 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1104 | ||
82b0f8c3 | 1105 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1106 | { |
1107 | pmd_t entry; | |
1108 | unsigned long haddr; | |
20f664aa | 1109 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1110 | |
82b0f8c3 JK |
1111 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1112 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1113 | goto unlock; |
1114 | ||
1115 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1116 | if (write) |
1117 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1118 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1119 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1120 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1121 | |
1122 | unlock: | |
82b0f8c3 | 1123 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1124 | } |
1125 | ||
2b740303 SJ |
1126 | static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, |
1127 | pmd_t orig_pmd, struct page *page) | |
71e3aac0 | 1128 | { |
82b0f8c3 JK |
1129 | struct vm_area_struct *vma = vmf->vma; |
1130 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1131 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1132 | pgtable_t pgtable; |
1133 | pmd_t _pmd; | |
2b740303 SJ |
1134 | int i; |
1135 | vm_fault_t ret = 0; | |
71e3aac0 | 1136 | struct page **pages; |
ac46d4f3 | 1137 | struct mmu_notifier_range range; |
71e3aac0 | 1138 | |
6da2ec56 KC |
1139 | pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), |
1140 | GFP_KERNEL); | |
71e3aac0 AA |
1141 | if (unlikely(!pages)) { |
1142 | ret |= VM_FAULT_OOM; | |
1143 | goto out; | |
1144 | } | |
1145 | ||
1146 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1147 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1148 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1149 | if (unlikely(!pages[i] || |
2cf85583 | 1150 | mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, |
bae473a4 | 1151 | GFP_KERNEL, &memcg, false))) { |
b9bbfbe3 | 1152 | if (pages[i]) |
71e3aac0 | 1153 | put_page(pages[i]); |
b9bbfbe3 | 1154 | while (--i >= 0) { |
00501b53 JW |
1155 | memcg = (void *)page_private(pages[i]); |
1156 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1157 | mem_cgroup_cancel_charge(pages[i], memcg, |
1158 | false); | |
b9bbfbe3 AA |
1159 | put_page(pages[i]); |
1160 | } | |
71e3aac0 AA |
1161 | kfree(pages); |
1162 | ret |= VM_FAULT_OOM; | |
1163 | goto out; | |
1164 | } | |
00501b53 | 1165 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1166 | } |
1167 | ||
1168 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1169 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1170 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1171 | __SetPageUptodate(pages[i]); |
1172 | cond_resched(); | |
1173 | } | |
1174 | ||
ac46d4f3 JG |
1175 | mmu_notifier_range_init(&range, vma->vm_mm, haddr, |
1176 | haddr + HPAGE_PMD_SIZE); | |
1177 | mmu_notifier_invalidate_range_start(&range); | |
2ec74c3e | 1178 | |
82b0f8c3 JK |
1179 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1180 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1181 | goto out_free_pages; |
309381fe | 1182 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1183 | |
0f10851e JG |
1184 | /* |
1185 | * Leave pmd empty until pte is filled note we must notify here as | |
1186 | * concurrent CPU thread might write to new page before the call to | |
1187 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1188 | * device seeing memory write in different order than CPU. | |
1189 | * | |
ad56b738 | 1190 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 1191 | */ |
82b0f8c3 | 1192 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1193 | |
82b0f8c3 | 1194 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1195 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1196 | |
1197 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1198 | pte_t entry; |
71e3aac0 AA |
1199 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1200 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1201 | memcg = (void *)page_private(pages[i]); |
1202 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1203 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1204 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1205 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1206 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1207 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1208 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1209 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1210 | } |
1211 | kfree(pages); | |
1212 | ||
71e3aac0 | 1213 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1214 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1215 | page_remove_rmap(page, true); |
82b0f8c3 | 1216 | spin_unlock(vmf->ptl); |
71e3aac0 | 1217 | |
4645b9fe JG |
1218 | /* |
1219 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1220 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1221 | */ | |
ac46d4f3 | 1222 | mmu_notifier_invalidate_range_only_end(&range); |
2ec74c3e | 1223 | |
71e3aac0 AA |
1224 | ret |= VM_FAULT_WRITE; |
1225 | put_page(page); | |
1226 | ||
1227 | out: | |
1228 | return ret; | |
1229 | ||
1230 | out_free_pages: | |
82b0f8c3 | 1231 | spin_unlock(vmf->ptl); |
ac46d4f3 | 1232 | mmu_notifier_invalidate_range_end(&range); |
b9bbfbe3 | 1233 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1234 | memcg = (void *)page_private(pages[i]); |
1235 | set_page_private(pages[i], 0); | |
f627c2f5 | 1236 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1237 | put_page(pages[i]); |
b9bbfbe3 | 1238 | } |
71e3aac0 AA |
1239 | kfree(pages); |
1240 | goto out; | |
1241 | } | |
1242 | ||
2b740303 | 1243 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1244 | { |
82b0f8c3 | 1245 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1246 | struct page *page = NULL, *new_page; |
00501b53 | 1247 | struct mem_cgroup *memcg; |
82b0f8c3 | 1248 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
ac46d4f3 | 1249 | struct mmu_notifier_range range; |
3b363692 | 1250 | gfp_t huge_gfp; /* for allocation and charge */ |
2b740303 | 1251 | vm_fault_t ret = 0; |
71e3aac0 | 1252 | |
82b0f8c3 | 1253 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1254 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1255 | if (is_huge_zero_pmd(orig_pmd)) |
1256 | goto alloc; | |
82b0f8c3 JK |
1257 | spin_lock(vmf->ptl); |
1258 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1259 | goto out_unlock; |
1260 | ||
1261 | page = pmd_page(orig_pmd); | |
309381fe | 1262 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1263 | /* |
1264 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1265 | * part. |
1f25fe20 | 1266 | */ |
ba3c4ce6 HY |
1267 | if (!trylock_page(page)) { |
1268 | get_page(page); | |
1269 | spin_unlock(vmf->ptl); | |
1270 | lock_page(page); | |
1271 | spin_lock(vmf->ptl); | |
1272 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1273 | unlock_page(page); | |
1274 | put_page(page); | |
1275 | goto out_unlock; | |
1276 | } | |
1277 | put_page(page); | |
1278 | } | |
1279 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1280 | pmd_t entry; |
1281 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1282 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1283 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1284 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1285 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1286 | unlock_page(page); |
71e3aac0 AA |
1287 | goto out_unlock; |
1288 | } | |
ba3c4ce6 | 1289 | unlock_page(page); |
ddc58f27 | 1290 | get_page(page); |
82b0f8c3 | 1291 | spin_unlock(vmf->ptl); |
93b4796d | 1292 | alloc: |
71e3aac0 | 1293 | if (transparent_hugepage_enabled(vma) && |
077fcf11 | 1294 | !transparent_hugepage_debug_cow()) { |
356ff8a9 DR |
1295 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
1296 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); | |
077fcf11 | 1297 | } else |
71e3aac0 AA |
1298 | new_page = NULL; |
1299 | ||
9a982250 KS |
1300 | if (likely(new_page)) { |
1301 | prep_transhuge_page(new_page); | |
1302 | } else { | |
eecc1e42 | 1303 | if (!page) { |
82b0f8c3 | 1304 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1305 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1306 | } else { |
82b0f8c3 | 1307 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1308 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1309 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1310 | ret |= VM_FAULT_FALLBACK; |
1311 | } | |
ddc58f27 | 1312 | put_page(page); |
93b4796d | 1313 | } |
17766dde | 1314 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1315 | goto out; |
1316 | } | |
1317 | ||
2cf85583 | 1318 | if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, |
2a70f6a7 | 1319 | huge_gfp, &memcg, true))) { |
b9bbfbe3 | 1320 | put_page(new_page); |
82b0f8c3 | 1321 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1322 | if (page) |
ddc58f27 | 1323 | put_page(page); |
9845cbbd | 1324 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1325 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1326 | goto out; |
1327 | } | |
1328 | ||
17766dde DR |
1329 | count_vm_event(THP_FAULT_ALLOC); |
1330 | ||
eecc1e42 | 1331 | if (!page) |
c79b57e4 | 1332 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d | 1333 | else |
c9f4cd71 HY |
1334 | copy_user_huge_page(new_page, page, vmf->address, |
1335 | vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1336 | __SetPageUptodate(new_page); |
1337 | ||
ac46d4f3 JG |
1338 | mmu_notifier_range_init(&range, vma->vm_mm, haddr, |
1339 | haddr + HPAGE_PMD_SIZE); | |
1340 | mmu_notifier_invalidate_range_start(&range); | |
2ec74c3e | 1341 | |
82b0f8c3 | 1342 | spin_lock(vmf->ptl); |
93b4796d | 1343 | if (page) |
ddc58f27 | 1344 | put_page(page); |
82b0f8c3 JK |
1345 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1346 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1347 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1348 | put_page(new_page); |
2ec74c3e | 1349 | goto out_mn; |
b9bbfbe3 | 1350 | } else { |
71e3aac0 | 1351 | pmd_t entry; |
3122359a | 1352 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
f55e1014 | 1353 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 | 1354 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1355 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1356 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1357 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1358 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1359 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1360 | if (!page) { |
bae473a4 | 1361 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1362 | } else { |
309381fe | 1363 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1364 | page_remove_rmap(page, true); |
93b4796d KS |
1365 | put_page(page); |
1366 | } | |
71e3aac0 AA |
1367 | ret |= VM_FAULT_WRITE; |
1368 | } | |
82b0f8c3 | 1369 | spin_unlock(vmf->ptl); |
2ec74c3e | 1370 | out_mn: |
4645b9fe JG |
1371 | /* |
1372 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1373 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1374 | */ | |
ac46d4f3 | 1375 | mmu_notifier_invalidate_range_only_end(&range); |
71e3aac0 AA |
1376 | out: |
1377 | return ret; | |
2ec74c3e | 1378 | out_unlock: |
82b0f8c3 | 1379 | spin_unlock(vmf->ptl); |
2ec74c3e | 1380 | return ret; |
71e3aac0 AA |
1381 | } |
1382 | ||
8310d48b KF |
1383 | /* |
1384 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1385 | * after we've gone through a COW cycle and they are dirty. | |
1386 | */ | |
1387 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1388 | { | |
f6f37321 | 1389 | return pmd_write(pmd) || |
8310d48b KF |
1390 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); |
1391 | } | |
1392 | ||
b676b293 | 1393 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1394 | unsigned long addr, |
1395 | pmd_t *pmd, | |
1396 | unsigned int flags) | |
1397 | { | |
b676b293 | 1398 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1399 | struct page *page = NULL; |
1400 | ||
c4088ebd | 1401 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1402 | |
8310d48b | 1403 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1404 | goto out; |
1405 | ||
85facf25 KS |
1406 | /* Avoid dumping huge zero page */ |
1407 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1408 | return ERR_PTR(-EFAULT); | |
1409 | ||
2b4847e7 | 1410 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1411 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1412 | goto out; |
1413 | ||
71e3aac0 | 1414 | page = pmd_page(*pmd); |
ca120cf6 | 1415 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1416 | if (flags & FOLL_TOUCH) |
a8f97366 | 1417 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1418 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1419 | /* |
1420 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1421 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1422 | * | |
9a73f61b KS |
1423 | * For anon THP: |
1424 | * | |
e90309c9 KS |
1425 | * In most cases the pmd is the only mapping of the page as we |
1426 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1427 | * writable private mappings in populate_vma_page_range(). | |
1428 | * | |
1429 | * The only scenario when we have the page shared here is if we | |
1430 | * mlocking read-only mapping shared over fork(). We skip | |
1431 | * mlocking such pages. | |
9a73f61b KS |
1432 | * |
1433 | * For file THP: | |
1434 | * | |
1435 | * We can expect PageDoubleMap() to be stable under page lock: | |
1436 | * for file pages we set it in page_add_file_rmap(), which | |
1437 | * requires page to be locked. | |
e90309c9 | 1438 | */ |
9a73f61b KS |
1439 | |
1440 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1441 | goto skip_mlock; | |
1442 | if (PageDoubleMap(page) || !page->mapping) | |
1443 | goto skip_mlock; | |
1444 | if (!trylock_page(page)) | |
1445 | goto skip_mlock; | |
1446 | lru_add_drain(); | |
1447 | if (page->mapping && !PageDoubleMap(page)) | |
1448 | mlock_vma_page(page); | |
1449 | unlock_page(page); | |
b676b293 | 1450 | } |
9a73f61b | 1451 | skip_mlock: |
71e3aac0 | 1452 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1453 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1454 | if (flags & FOLL_GET) |
ddc58f27 | 1455 | get_page(page); |
71e3aac0 AA |
1456 | |
1457 | out: | |
1458 | return page; | |
1459 | } | |
1460 | ||
d10e63f2 | 1461 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1462 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1463 | { |
82b0f8c3 | 1464 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1465 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1466 | struct page *page; |
82b0f8c3 | 1467 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
8191acbd | 1468 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1469 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1470 | bool page_locked; |
1471 | bool migrated = false; | |
b191f9b1 | 1472 | bool was_writable; |
6688cc05 | 1473 | int flags = 0; |
d10e63f2 | 1474 | |
82b0f8c3 JK |
1475 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1476 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1477 | goto out_unlock; |
1478 | ||
de466bd6 MG |
1479 | /* |
1480 | * If there are potential migrations, wait for completion and retry | |
1481 | * without disrupting NUMA hinting information. Do not relock and | |
1482 | * check_same as the page may no longer be mapped. | |
1483 | */ | |
82b0f8c3 JK |
1484 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1485 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1486 | if (!get_page_unless_zero(page)) |
1487 | goto out_unlock; | |
82b0f8c3 | 1488 | spin_unlock(vmf->ptl); |
9a1ea439 | 1489 | put_and_wait_on_page_locked(page); |
de466bd6 MG |
1490 | goto out; |
1491 | } | |
1492 | ||
d10e63f2 | 1493 | page = pmd_page(pmd); |
a1a46184 | 1494 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1495 | page_nid = page_to_nid(page); |
90572890 | 1496 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1497 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1498 | if (page_nid == this_nid) { |
03c5a6e1 | 1499 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1500 | flags |= TNF_FAULT_LOCAL; |
1501 | } | |
4daae3b4 | 1502 | |
bea66fbd | 1503 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1504 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1505 | flags |= TNF_NO_GROUP; |
1506 | ||
ff9042b1 MG |
1507 | /* |
1508 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1509 | * page_table_lock if at all possible | |
1510 | */ | |
b8916634 MG |
1511 | page_locked = trylock_page(page); |
1512 | target_nid = mpol_misplaced(page, vma, haddr); | |
1513 | if (target_nid == -1) { | |
1514 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1515 | if (page_locked) |
b8916634 | 1516 | goto clear_pmdnuma; |
2b4847e7 | 1517 | } |
4daae3b4 | 1518 | |
de466bd6 | 1519 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1520 | if (!page_locked) { |
3c226c63 MR |
1521 | page_nid = -1; |
1522 | if (!get_page_unless_zero(page)) | |
1523 | goto out_unlock; | |
82b0f8c3 | 1524 | spin_unlock(vmf->ptl); |
9a1ea439 | 1525 | put_and_wait_on_page_locked(page); |
b8916634 MG |
1526 | goto out; |
1527 | } | |
1528 | ||
2b4847e7 MG |
1529 | /* |
1530 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1531 | * to serialises splits | |
1532 | */ | |
b8916634 | 1533 | get_page(page); |
82b0f8c3 | 1534 | spin_unlock(vmf->ptl); |
b8916634 | 1535 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1536 | |
c69307d5 | 1537 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1538 | spin_lock(vmf->ptl); |
1539 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1540 | unlock_page(page); |
1541 | put_page(page); | |
a54a407f | 1542 | page_nid = -1; |
4daae3b4 | 1543 | goto out_unlock; |
b32967ff | 1544 | } |
ff9042b1 | 1545 | |
c3a489ca MG |
1546 | /* Bail if we fail to protect against THP splits for any reason */ |
1547 | if (unlikely(!anon_vma)) { | |
1548 | put_page(page); | |
1549 | page_nid = -1; | |
1550 | goto clear_pmdnuma; | |
1551 | } | |
1552 | ||
8b1b436d PZ |
1553 | /* |
1554 | * Since we took the NUMA fault, we must have observed the !accessible | |
1555 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1556 | * modifying the page we're about to migrate. | |
1557 | * | |
1558 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1559 | * inc_tlb_flush_pending(). |
1560 | * | |
1561 | * We are not sure a pending tlb flush here is for a huge page | |
1562 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1563 | */ |
7066f0f9 | 1564 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1565 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1566 | /* |
1567 | * change_huge_pmd() released the pmd lock before | |
1568 | * invalidating the secondary MMUs sharing the primary | |
1569 | * MMU pagetables (with ->invalidate_range()). The | |
1570 | * mmu_notifier_invalidate_range_end() (which | |
1571 | * internally calls ->invalidate_range()) in | |
1572 | * change_pmd_range() will run after us, so we can't | |
1573 | * rely on it here and we need an explicit invalidate. | |
1574 | */ | |
1575 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1576 | haddr + HPAGE_PMD_SIZE); | |
1577 | } | |
8b1b436d | 1578 | |
a54a407f MG |
1579 | /* |
1580 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1581 | * and access rights restored. |
a54a407f | 1582 | */ |
82b0f8c3 | 1583 | spin_unlock(vmf->ptl); |
8b1b436d | 1584 | |
bae473a4 | 1585 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1586 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1587 | if (migrated) { |
1588 | flags |= TNF_MIGRATED; | |
8191acbd | 1589 | page_nid = target_nid; |
074c2381 MG |
1590 | } else |
1591 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1592 | |
8191acbd | 1593 | goto out; |
b32967ff | 1594 | clear_pmdnuma: |
a54a407f | 1595 | BUG_ON(!PageLocked(page)); |
288bc549 | 1596 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1597 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1598 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1599 | if (was_writable) |
1600 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1601 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1602 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1603 | unlock_page(page); |
d10e63f2 | 1604 | out_unlock: |
82b0f8c3 | 1605 | spin_unlock(vmf->ptl); |
b8916634 MG |
1606 | |
1607 | out: | |
1608 | if (anon_vma) | |
1609 | page_unlock_anon_vma_read(anon_vma); | |
1610 | ||
8191acbd | 1611 | if (page_nid != -1) |
82b0f8c3 | 1612 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1613 | flags); |
8191acbd | 1614 | |
d10e63f2 MG |
1615 | return 0; |
1616 | } | |
1617 | ||
319904ad HY |
1618 | /* |
1619 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1620 | * Otherwise, return false. | |
1621 | */ | |
1622 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1623 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1624 | { |
1625 | spinlock_t *ptl; | |
1626 | pmd_t orig_pmd; | |
1627 | struct page *page; | |
1628 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1629 | bool ret = false; |
b8d3c4c3 | 1630 | |
07e32661 AK |
1631 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1632 | ||
b6ec57f4 KS |
1633 | ptl = pmd_trans_huge_lock(pmd, vma); |
1634 | if (!ptl) | |
25eedabe | 1635 | goto out_unlocked; |
b8d3c4c3 MK |
1636 | |
1637 | orig_pmd = *pmd; | |
319904ad | 1638 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1639 | goto out; |
b8d3c4c3 | 1640 | |
84c3fc4e ZY |
1641 | if (unlikely(!pmd_present(orig_pmd))) { |
1642 | VM_BUG_ON(thp_migration_supported() && | |
1643 | !is_pmd_migration_entry(orig_pmd)); | |
1644 | goto out; | |
1645 | } | |
1646 | ||
b8d3c4c3 MK |
1647 | page = pmd_page(orig_pmd); |
1648 | /* | |
1649 | * If other processes are mapping this page, we couldn't discard | |
1650 | * the page unless they all do MADV_FREE so let's skip the page. | |
1651 | */ | |
1652 | if (page_mapcount(page) != 1) | |
1653 | goto out; | |
1654 | ||
1655 | if (!trylock_page(page)) | |
1656 | goto out; | |
1657 | ||
1658 | /* | |
1659 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1660 | * will deactivate only them. | |
1661 | */ | |
1662 | if (next - addr != HPAGE_PMD_SIZE) { | |
1663 | get_page(page); | |
1664 | spin_unlock(ptl); | |
9818b8cd | 1665 | split_huge_page(page); |
b8d3c4c3 | 1666 | unlock_page(page); |
bbf29ffc | 1667 | put_page(page); |
b8d3c4c3 MK |
1668 | goto out_unlocked; |
1669 | } | |
1670 | ||
1671 | if (PageDirty(page)) | |
1672 | ClearPageDirty(page); | |
1673 | unlock_page(page); | |
1674 | ||
b8d3c4c3 | 1675 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1676 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1677 | orig_pmd = pmd_mkold(orig_pmd); |
1678 | orig_pmd = pmd_mkclean(orig_pmd); | |
1679 | ||
1680 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1681 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1682 | } | |
802a3a92 SL |
1683 | |
1684 | mark_page_lazyfree(page); | |
319904ad | 1685 | ret = true; |
b8d3c4c3 MK |
1686 | out: |
1687 | spin_unlock(ptl); | |
1688 | out_unlocked: | |
1689 | return ret; | |
1690 | } | |
1691 | ||
953c66c2 AK |
1692 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1693 | { | |
1694 | pgtable_t pgtable; | |
1695 | ||
1696 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1697 | pte_free(mm, pgtable); | |
c4812909 | 1698 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1699 | } |
1700 | ||
71e3aac0 | 1701 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1702 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1703 | { |
da146769 | 1704 | pmd_t orig_pmd; |
bf929152 | 1705 | spinlock_t *ptl; |
71e3aac0 | 1706 | |
07e32661 AK |
1707 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1708 | ||
b6ec57f4 KS |
1709 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1710 | if (!ptl) | |
da146769 KS |
1711 | return 0; |
1712 | /* | |
1713 | * For architectures like ppc64 we look at deposited pgtable | |
1714 | * when calling pmdp_huge_get_and_clear. So do the | |
1715 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1716 | * operations. | |
1717 | */ | |
1718 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1719 | tlb->fullmm); | |
1720 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1721 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1722 | if (arch_needs_pgtable_deposit()) |
1723 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1724 | spin_unlock(ptl); |
1725 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1726 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1727 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1728 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1729 | spin_unlock(ptl); |
c0f2e176 | 1730 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1731 | } else { |
616b8371 ZY |
1732 | struct page *page = NULL; |
1733 | int flush_needed = 1; | |
1734 | ||
1735 | if (pmd_present(orig_pmd)) { | |
1736 | page = pmd_page(orig_pmd); | |
1737 | page_remove_rmap(page, true); | |
1738 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1739 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1740 | } else if (thp_migration_supported()) { | |
1741 | swp_entry_t entry; | |
1742 | ||
1743 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1744 | entry = pmd_to_swp_entry(orig_pmd); | |
1745 | page = pfn_to_page(swp_offset(entry)); | |
1746 | flush_needed = 0; | |
1747 | } else | |
1748 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1749 | ||
b5072380 | 1750 | if (PageAnon(page)) { |
c14a6eb4 | 1751 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1752 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1753 | } else { | |
953c66c2 AK |
1754 | if (arch_needs_pgtable_deposit()) |
1755 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1756 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1757 | } |
616b8371 | 1758 | |
da146769 | 1759 | spin_unlock(ptl); |
616b8371 ZY |
1760 | if (flush_needed) |
1761 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1762 | } |
da146769 | 1763 | return 1; |
71e3aac0 AA |
1764 | } |
1765 | ||
1dd38b6c AK |
1766 | #ifndef pmd_move_must_withdraw |
1767 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1768 | spinlock_t *old_pmd_ptl, | |
1769 | struct vm_area_struct *vma) | |
1770 | { | |
1771 | /* | |
1772 | * With split pmd lock we also need to move preallocated | |
1773 | * PTE page table if new_pmd is on different PMD page table. | |
1774 | * | |
1775 | * We also don't deposit and withdraw tables for file pages. | |
1776 | */ | |
1777 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1778 | } | |
1779 | #endif | |
1780 | ||
ab6e3d09 NH |
1781 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1782 | { | |
1783 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1784 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1785 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1786 | else if (pmd_present(pmd)) | |
1787 | pmd = pmd_mksoft_dirty(pmd); | |
1788 | #endif | |
1789 | return pmd; | |
1790 | } | |
1791 | ||
bf8616d5 | 1792 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1793 | unsigned long new_addr, unsigned long old_end, |
eb66ae03 | 1794 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1795 | { |
bf929152 | 1796 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1797 | pmd_t pmd; |
37a1c49a | 1798 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1799 | bool force_flush = false; |
37a1c49a AA |
1800 | |
1801 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1802 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1803 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1804 | return false; |
37a1c49a AA |
1805 | |
1806 | /* | |
1807 | * The destination pmd shouldn't be established, free_pgtables() | |
1808 | * should have release it. | |
1809 | */ | |
1810 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1811 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1812 | return false; |
37a1c49a AA |
1813 | } |
1814 | ||
bf929152 KS |
1815 | /* |
1816 | * We don't have to worry about the ordering of src and dst | |
1817 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1818 | */ | |
b6ec57f4 KS |
1819 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1820 | if (old_ptl) { | |
bf929152 KS |
1821 | new_ptl = pmd_lockptr(mm, new_pmd); |
1822 | if (new_ptl != old_ptl) | |
1823 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1824 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1825 | if (pmd_present(pmd)) |
a2ce2666 | 1826 | force_flush = true; |
025c5b24 | 1827 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1828 | |
1dd38b6c | 1829 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1830 | pgtable_t pgtable; |
3592806c KS |
1831 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1832 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1833 | } |
ab6e3d09 NH |
1834 | pmd = move_soft_dirty_pmd(pmd); |
1835 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1836 | if (force_flush) |
1837 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1838 | if (new_ptl != old_ptl) |
1839 | spin_unlock(new_ptl); | |
bf929152 | 1840 | spin_unlock(old_ptl); |
4b471e88 | 1841 | return true; |
37a1c49a | 1842 | } |
4b471e88 | 1843 | return false; |
37a1c49a AA |
1844 | } |
1845 | ||
f123d74a MG |
1846 | /* |
1847 | * Returns | |
1848 | * - 0 if PMD could not be locked | |
1849 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1850 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1851 | */ | |
cd7548ab | 1852 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1853 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1854 | { |
1855 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1856 | spinlock_t *ptl; |
0a85e51d KS |
1857 | pmd_t entry; |
1858 | bool preserve_write; | |
1859 | int ret; | |
cd7548ab | 1860 | |
b6ec57f4 | 1861 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1862 | if (!ptl) |
1863 | return 0; | |
e944fd67 | 1864 | |
0a85e51d KS |
1865 | preserve_write = prot_numa && pmd_write(*pmd); |
1866 | ret = 1; | |
e944fd67 | 1867 | |
84c3fc4e ZY |
1868 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1869 | if (is_swap_pmd(*pmd)) { | |
1870 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1871 | ||
1872 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1873 | if (is_write_migration_entry(entry)) { | |
1874 | pmd_t newpmd; | |
1875 | /* | |
1876 | * A protection check is difficult so | |
1877 | * just be safe and disable write | |
1878 | */ | |
1879 | make_migration_entry_read(&entry); | |
1880 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1881 | if (pmd_swp_soft_dirty(*pmd)) |
1882 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1883 | set_pmd_at(mm, addr, pmd, newpmd); |
1884 | } | |
1885 | goto unlock; | |
1886 | } | |
1887 | #endif | |
1888 | ||
0a85e51d KS |
1889 | /* |
1890 | * Avoid trapping faults against the zero page. The read-only | |
1891 | * data is likely to be read-cached on the local CPU and | |
1892 | * local/remote hits to the zero page are not interesting. | |
1893 | */ | |
1894 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1895 | goto unlock; | |
025c5b24 | 1896 | |
0a85e51d KS |
1897 | if (prot_numa && pmd_protnone(*pmd)) |
1898 | goto unlock; | |
1899 | ||
ced10803 KS |
1900 | /* |
1901 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1902 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1903 | * which is also under down_read(mmap_sem): | |
1904 | * | |
1905 | * CPU0: CPU1: | |
1906 | * change_huge_pmd(prot_numa=1) | |
1907 | * pmdp_huge_get_and_clear_notify() | |
1908 | * madvise_dontneed() | |
1909 | * zap_pmd_range() | |
1910 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1911 | * // skip the pmd | |
1912 | * set_pmd_at(); | |
1913 | * // pmd is re-established | |
1914 | * | |
1915 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1916 | * which may break userspace. | |
1917 | * | |
1918 | * pmdp_invalidate() is required to make sure we don't miss | |
1919 | * dirty/young flags set by hardware. | |
1920 | */ | |
a3cf988f | 1921 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1922 | |
0a85e51d KS |
1923 | entry = pmd_modify(entry, newprot); |
1924 | if (preserve_write) | |
1925 | entry = pmd_mk_savedwrite(entry); | |
1926 | ret = HPAGE_PMD_NR; | |
1927 | set_pmd_at(mm, addr, pmd, entry); | |
1928 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1929 | unlock: | |
1930 | spin_unlock(ptl); | |
025c5b24 NH |
1931 | return ret; |
1932 | } | |
1933 | ||
1934 | /* | |
8f19b0c0 | 1935 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1936 | * |
8f19b0c0 HY |
1937 | * Note that if it returns page table lock pointer, this routine returns without |
1938 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1939 | */ |
b6ec57f4 | 1940 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1941 | { |
b6ec57f4 KS |
1942 | spinlock_t *ptl; |
1943 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1944 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1945 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1946 | return ptl; |
1947 | spin_unlock(ptl); | |
1948 | return NULL; | |
cd7548ab JW |
1949 | } |
1950 | ||
a00cc7d9 MW |
1951 | /* |
1952 | * Returns true if a given pud maps a thp, false otherwise. | |
1953 | * | |
1954 | * Note that if it returns true, this routine returns without unlocking page | |
1955 | * table lock. So callers must unlock it. | |
1956 | */ | |
1957 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1958 | { | |
1959 | spinlock_t *ptl; | |
1960 | ||
1961 | ptl = pud_lock(vma->vm_mm, pud); | |
1962 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1963 | return ptl; | |
1964 | spin_unlock(ptl); | |
1965 | return NULL; | |
1966 | } | |
1967 | ||
1968 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1969 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1970 | pud_t *pud, unsigned long addr) | |
1971 | { | |
1972 | pud_t orig_pud; | |
1973 | spinlock_t *ptl; | |
1974 | ||
1975 | ptl = __pud_trans_huge_lock(pud, vma); | |
1976 | if (!ptl) | |
1977 | return 0; | |
1978 | /* | |
1979 | * For architectures like ppc64 we look at deposited pgtable | |
1980 | * when calling pudp_huge_get_and_clear. So do the | |
1981 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1982 | * operations. | |
1983 | */ | |
1984 | orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, | |
1985 | tlb->fullmm); | |
1986 | tlb_remove_pud_tlb_entry(tlb, pud, addr); | |
1987 | if (vma_is_dax(vma)) { | |
1988 | spin_unlock(ptl); | |
1989 | /* No zero page support yet */ | |
1990 | } else { | |
1991 | /* No support for anonymous PUD pages yet */ | |
1992 | BUG(); | |
1993 | } | |
1994 | return 1; | |
1995 | } | |
1996 | ||
1997 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1998 | unsigned long haddr) | |
1999 | { | |
2000 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2001 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2002 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2003 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2004 | ||
ce9311cf | 2005 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2006 | |
2007 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2008 | } | |
2009 | ||
2010 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2011 | unsigned long address) | |
2012 | { | |
2013 | spinlock_t *ptl; | |
ac46d4f3 | 2014 | struct mmu_notifier_range range; |
a00cc7d9 | 2015 | |
ac46d4f3 JG |
2016 | mmu_notifier_range_init(&range, vma->vm_mm, address & HPAGE_PUD_MASK, |
2017 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); | |
2018 | mmu_notifier_invalidate_range_start(&range); | |
2019 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2020 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2021 | goto out; | |
ac46d4f3 | 2022 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2023 | |
2024 | out: | |
2025 | spin_unlock(ptl); | |
4645b9fe JG |
2026 | /* |
2027 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2028 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2029 | */ | |
ac46d4f3 | 2030 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2031 | } |
2032 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2033 | ||
eef1b3ba KS |
2034 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2035 | unsigned long haddr, pmd_t *pmd) | |
2036 | { | |
2037 | struct mm_struct *mm = vma->vm_mm; | |
2038 | pgtable_t pgtable; | |
2039 | pmd_t _pmd; | |
2040 | int i; | |
2041 | ||
0f10851e JG |
2042 | /* |
2043 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2044 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2045 | * replacing a zero pmd write protected page with a zero pte write | |
2046 | * protected page. | |
2047 | * | |
ad56b738 | 2048 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2049 | */ |
2050 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2051 | |
2052 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2053 | pmd_populate(mm, &_pmd, pgtable); | |
2054 | ||
2055 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2056 | pte_t *pte, entry; | |
2057 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2058 | entry = pte_mkspecial(entry); | |
2059 | pte = pte_offset_map(&_pmd, haddr); | |
2060 | VM_BUG_ON(!pte_none(*pte)); | |
2061 | set_pte_at(mm, haddr, pte, entry); | |
2062 | pte_unmap(pte); | |
2063 | } | |
2064 | smp_wmb(); /* make pte visible before pmd */ | |
2065 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2066 | } |
2067 | ||
2068 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2069 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2070 | { |
2071 | struct mm_struct *mm = vma->vm_mm; | |
2072 | struct page *page; | |
2073 | pgtable_t pgtable; | |
423ac9af | 2074 | pmd_t old_pmd, _pmd; |
a3cf988f | 2075 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2076 | unsigned long addr; |
eef1b3ba KS |
2077 | int i; |
2078 | ||
2079 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2080 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2081 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2082 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2083 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2084 | |
2085 | count_vm_event(THP_SPLIT_PMD); | |
2086 | ||
d21b9e57 KS |
2087 | if (!vma_is_anonymous(vma)) { |
2088 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2089 | /* |
2090 | * We are going to unmap this huge page. So | |
2091 | * just go ahead and zap it | |
2092 | */ | |
2093 | if (arch_needs_pgtable_deposit()) | |
2094 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2095 | if (vma_is_dax(vma)) |
2096 | return; | |
2097 | page = pmd_page(_pmd); | |
e1f1b157 HD |
2098 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2099 | set_page_dirty(page); | |
d21b9e57 KS |
2100 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2101 | SetPageReferenced(page); | |
2102 | page_remove_rmap(page, true); | |
2103 | put_page(page); | |
fadae295 | 2104 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba KS |
2105 | return; |
2106 | } else if (is_huge_zero_pmd(*pmd)) { | |
4645b9fe JG |
2107 | /* |
2108 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2109 | * mmu_notifier_invalidate_range() see comments below inside | |
2110 | * __split_huge_pmd() ? | |
2111 | * | |
2112 | * We are going from a zero huge page write protected to zero | |
2113 | * small page also write protected so it does not seems useful | |
2114 | * to invalidate secondary mmu at this time. | |
2115 | */ | |
eef1b3ba KS |
2116 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2117 | } | |
2118 | ||
423ac9af AK |
2119 | /* |
2120 | * Up to this point the pmd is present and huge and userland has the | |
2121 | * whole access to the hugepage during the split (which happens in | |
2122 | * place). If we overwrite the pmd with the not-huge version pointing | |
2123 | * to the pte here (which of course we could if all CPUs were bug | |
2124 | * free), userland could trigger a small page size TLB miss on the | |
2125 | * small sized TLB while the hugepage TLB entry is still established in | |
2126 | * the huge TLB. Some CPU doesn't like that. | |
2127 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2128 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2129 | * only safe if the permission and cache attributes of the two entries | |
2130 | * loaded in the two TLB is identical (which should be the case here). | |
2131 | * But it is generally safer to never allow small and huge TLB entries | |
2132 | * for the same virtual address to be loaded simultaneously. So instead | |
2133 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2134 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2135 | * must remain set at all times on the pmd until the split is complete | |
2136 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2137 | * non-huge version of the pmd entry with pmd_populate. | |
2138 | */ | |
2139 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2140 | ||
423ac9af | 2141 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2142 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2143 | swp_entry_t entry; |
2144 | ||
423ac9af | 2145 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e | 2146 | page = pfn_to_page(swp_offset(entry)); |
2e83ee1d PX |
2147 | write = is_write_migration_entry(entry); |
2148 | young = false; | |
2149 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
2150 | } else { | |
423ac9af | 2151 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2152 | if (pmd_dirty(old_pmd)) |
2153 | SetPageDirty(page); | |
2154 | write = pmd_write(old_pmd); | |
2155 | young = pmd_young(old_pmd); | |
2156 | soft_dirty = pmd_soft_dirty(old_pmd); | |
2157 | } | |
eef1b3ba | 2158 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2159 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2160 | |
423ac9af AK |
2161 | /* |
2162 | * Withdraw the table only after we mark the pmd entry invalid. | |
2163 | * This's critical for some architectures (Power). | |
2164 | */ | |
eef1b3ba KS |
2165 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2166 | pmd_populate(mm, &_pmd, pgtable); | |
2167 | ||
2ac015e2 | 2168 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2169 | pte_t entry, *pte; |
2170 | /* | |
2171 | * Note that NUMA hinting access restrictions are not | |
2172 | * transferred to avoid any possibility of altering | |
2173 | * permissions across VMAs. | |
2174 | */ | |
84c3fc4e | 2175 | if (freeze || pmd_migration) { |
ba988280 KS |
2176 | swp_entry_t swp_entry; |
2177 | swp_entry = make_migration_entry(page + i, write); | |
2178 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2179 | if (soft_dirty) |
2180 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2181 | } else { |
6d2329f8 | 2182 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2183 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2184 | if (!write) |
2185 | entry = pte_wrprotect(entry); | |
2186 | if (!young) | |
2187 | entry = pte_mkold(entry); | |
804dd150 AA |
2188 | if (soft_dirty) |
2189 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2190 | } |
2ac015e2 | 2191 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2192 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2193 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2194 | atomic_inc(&page[i]._mapcount); |
2195 | pte_unmap(pte); | |
2196 | } | |
2197 | ||
2198 | /* | |
2199 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2200 | * false-negative page_mapped(). | |
2201 | */ | |
2202 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2203 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2204 | atomic_inc(&page[i]._mapcount); | |
2205 | } | |
2206 | ||
2207 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2208 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2209 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2210 | if (TestClearPageDoubleMap(page)) { |
2211 | /* No need in mapcount reference anymore */ | |
2212 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2213 | atomic_dec(&page[i]._mapcount); | |
2214 | } | |
2215 | } | |
2216 | ||
2217 | smp_wmb(); /* make pte visible before pmd */ | |
2218 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2219 | |
2220 | if (freeze) { | |
2ac015e2 | 2221 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2222 | page_remove_rmap(page + i, false); |
2223 | put_page(page + i); | |
2224 | } | |
2225 | } | |
eef1b3ba KS |
2226 | } |
2227 | ||
2228 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2229 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2230 | { |
2231 | spinlock_t *ptl; | |
ac46d4f3 | 2232 | struct mmu_notifier_range range; |
eef1b3ba | 2233 | |
ac46d4f3 JG |
2234 | mmu_notifier_range_init(&range, vma->vm_mm, address & HPAGE_PMD_MASK, |
2235 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); | |
2236 | mmu_notifier_invalidate_range_start(&range); | |
2237 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2238 | |
2239 | /* | |
2240 | * If caller asks to setup a migration entries, we need a page to check | |
2241 | * pmd against. Otherwise we can end up replacing wrong page. | |
2242 | */ | |
2243 | VM_BUG_ON(freeze && !page); | |
2244 | if (page && page != pmd_page(*pmd)) | |
2245 | goto out; | |
2246 | ||
5c7fb56e | 2247 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2248 | page = pmd_page(*pmd); |
5c7fb56e | 2249 | if (PageMlocked(page)) |
5f737714 | 2250 | clear_page_mlock(page); |
84c3fc4e | 2251 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2252 | goto out; |
ac46d4f3 | 2253 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2254 | out: |
eef1b3ba | 2255 | spin_unlock(ptl); |
4645b9fe JG |
2256 | /* |
2257 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2258 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2259 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2260 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2261 | * fault will trigger a flush_notify before pointing to a new page | |
2262 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2263 | * page in the meantime) | |
2264 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2265 | * to invalidate secondary tlb entry they are all still valid. | |
2266 | * any further changes to individual pte will notify. So no need | |
2267 | * to call mmu_notifier->invalidate_range() | |
2268 | */ | |
ac46d4f3 | 2269 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2270 | } |
2271 | ||
fec89c10 KS |
2272 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2273 | bool freeze, struct page *page) | |
94fcc585 | 2274 | { |
f72e7dcd | 2275 | pgd_t *pgd; |
c2febafc | 2276 | p4d_t *p4d; |
f72e7dcd | 2277 | pud_t *pud; |
94fcc585 AA |
2278 | pmd_t *pmd; |
2279 | ||
78ddc534 | 2280 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2281 | if (!pgd_present(*pgd)) |
2282 | return; | |
2283 | ||
c2febafc KS |
2284 | p4d = p4d_offset(pgd, address); |
2285 | if (!p4d_present(*p4d)) | |
2286 | return; | |
2287 | ||
2288 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2289 | if (!pud_present(*pud)) |
2290 | return; | |
2291 | ||
2292 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2293 | |
33f4751e | 2294 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2295 | } |
2296 | ||
e1b9996b | 2297 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2298 | unsigned long start, |
2299 | unsigned long end, | |
2300 | long adjust_next) | |
2301 | { | |
2302 | /* | |
2303 | * If the new start address isn't hpage aligned and it could | |
2304 | * previously contain an hugepage: check if we need to split | |
2305 | * an huge pmd. | |
2306 | */ | |
2307 | if (start & ~HPAGE_PMD_MASK && | |
2308 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2309 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2310 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2311 | |
2312 | /* | |
2313 | * If the new end address isn't hpage aligned and it could | |
2314 | * previously contain an hugepage: check if we need to split | |
2315 | * an huge pmd. | |
2316 | */ | |
2317 | if (end & ~HPAGE_PMD_MASK && | |
2318 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2319 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2320 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2321 | |
2322 | /* | |
2323 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2324 | * vm_next->vm_start isn't page aligned and it could previously | |
2325 | * contain an hugepage: check if we need to split an huge pmd. | |
2326 | */ | |
2327 | if (adjust_next > 0) { | |
2328 | struct vm_area_struct *next = vma->vm_next; | |
2329 | unsigned long nstart = next->vm_start; | |
2330 | nstart += adjust_next << PAGE_SHIFT; | |
2331 | if (nstart & ~HPAGE_PMD_MASK && | |
2332 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2333 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2334 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2335 | } |
2336 | } | |
e9b61f19 | 2337 | |
906f9cdf | 2338 | static void unmap_page(struct page *page) |
e9b61f19 | 2339 | { |
baa355fd | 2340 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2341 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2342 | bool unmap_success; |
e9b61f19 KS |
2343 | |
2344 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2345 | ||
baa355fd | 2346 | if (PageAnon(page)) |
b5ff8161 | 2347 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2348 | |
666e5a40 MK |
2349 | unmap_success = try_to_unmap(page, ttu_flags); |
2350 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2351 | } |
2352 | ||
906f9cdf | 2353 | static void remap_page(struct page *page) |
e9b61f19 | 2354 | { |
fec89c10 | 2355 | int i; |
ace71a19 KS |
2356 | if (PageTransHuge(page)) { |
2357 | remove_migration_ptes(page, page, true); | |
2358 | } else { | |
2359 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2360 | remove_migration_ptes(page + i, page + i, true); | |
2361 | } | |
e9b61f19 KS |
2362 | } |
2363 | ||
8df651c7 | 2364 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2365 | struct lruvec *lruvec, struct list_head *list) |
2366 | { | |
e9b61f19 KS |
2367 | struct page *page_tail = head + tail; |
2368 | ||
8df651c7 | 2369 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2370 | |
2371 | /* | |
605ca5ed KK |
2372 | * Clone page flags before unfreezing refcount. |
2373 | * | |
2374 | * After successful get_page_unless_zero() might follow flags change, | |
2375 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2376 | */ |
e9b61f19 KS |
2377 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2378 | page_tail->flags |= (head->flags & | |
2379 | ((1L << PG_referenced) | | |
2380 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2381 | (1L << PG_swapcache) | |
e9b61f19 KS |
2382 | (1L << PG_mlocked) | |
2383 | (1L << PG_uptodate) | | |
2384 | (1L << PG_active) | | |
1899ad18 | 2385 | (1L << PG_workingset) | |
e9b61f19 | 2386 | (1L << PG_locked) | |
b8d3c4c3 MK |
2387 | (1L << PG_unevictable) | |
2388 | (1L << PG_dirty))); | |
e9b61f19 | 2389 | |
173d9d9f HD |
2390 | /* ->mapping in first tail page is compound_mapcount */ |
2391 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2392 | page_tail); | |
2393 | page_tail->mapping = head->mapping; | |
2394 | page_tail->index = head->index + tail; | |
2395 | ||
605ca5ed | 2396 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2397 | smp_wmb(); |
2398 | ||
605ca5ed KK |
2399 | /* |
2400 | * Clear PageTail before unfreezing page refcount. | |
2401 | * | |
2402 | * After successful get_page_unless_zero() might follow put_page() | |
2403 | * which needs correct compound_head(). | |
2404 | */ | |
e9b61f19 KS |
2405 | clear_compound_head(page_tail); |
2406 | ||
605ca5ed KK |
2407 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2408 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2409 | PageSwapCache(head))); | |
2410 | ||
e9b61f19 KS |
2411 | if (page_is_young(head)) |
2412 | set_page_young(page_tail); | |
2413 | if (page_is_idle(head)) | |
2414 | set_page_idle(page_tail); | |
2415 | ||
e9b61f19 | 2416 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2417 | |
2418 | /* | |
2419 | * always add to the tail because some iterators expect new | |
2420 | * pages to show after the currently processed elements - e.g. | |
2421 | * migrate_pages | |
2422 | */ | |
e9b61f19 | 2423 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2424 | } |
2425 | ||
baa355fd | 2426 | static void __split_huge_page(struct page *page, struct list_head *list, |
006d3ff2 | 2427 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2428 | { |
2429 | struct page *head = compound_head(page); | |
2430 | struct zone *zone = page_zone(head); | |
2431 | struct lruvec *lruvec; | |
8df651c7 | 2432 | int i; |
e9b61f19 | 2433 | |
599d0c95 | 2434 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
2435 | |
2436 | /* complete memcg works before add pages to LRU */ | |
2437 | mem_cgroup_split_huge_fixup(head); | |
2438 | ||
baa355fd | 2439 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2440 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2441 | /* Some pages can be beyond i_size: drop them from page cache */ |
2442 | if (head[i].index >= end) { | |
2d077d4b | 2443 | ClearPageDirty(head + i); |
baa355fd | 2444 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2445 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2446 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2447 | put_page(head + i); |
2448 | } | |
2449 | } | |
e9b61f19 KS |
2450 | |
2451 | ClearPageCompound(head); | |
baa355fd KS |
2452 | /* See comment in __split_huge_page_tail() */ |
2453 | if (PageAnon(head)) { | |
aa5dc07f | 2454 | /* Additional pin to swap cache */ |
38d8b4e6 HY |
2455 | if (PageSwapCache(head)) |
2456 | page_ref_add(head, 2); | |
2457 | else | |
2458 | page_ref_inc(head); | |
baa355fd | 2459 | } else { |
aa5dc07f | 2460 | /* Additional pin to page cache */ |
baa355fd | 2461 | page_ref_add(head, 2); |
b93b0163 | 2462 | xa_unlock(&head->mapping->i_pages); |
baa355fd KS |
2463 | } |
2464 | ||
a52633d8 | 2465 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 2466 | |
906f9cdf | 2467 | remap_page(head); |
e9b61f19 KS |
2468 | |
2469 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2470 | struct page *subpage = head + i; | |
2471 | if (subpage == page) | |
2472 | continue; | |
2473 | unlock_page(subpage); | |
2474 | ||
2475 | /* | |
2476 | * Subpages may be freed if there wasn't any mapping | |
2477 | * like if add_to_swap() is running on a lru page that | |
2478 | * had its mapping zapped. And freeing these pages | |
2479 | * requires taking the lru_lock so we do the put_page | |
2480 | * of the tail pages after the split is complete. | |
2481 | */ | |
2482 | put_page(subpage); | |
2483 | } | |
2484 | } | |
2485 | ||
b20ce5e0 KS |
2486 | int total_mapcount(struct page *page) |
2487 | { | |
dd78fedd | 2488 | int i, compound, ret; |
b20ce5e0 KS |
2489 | |
2490 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2491 | ||
2492 | if (likely(!PageCompound(page))) | |
2493 | return atomic_read(&page->_mapcount) + 1; | |
2494 | ||
dd78fedd | 2495 | compound = compound_mapcount(page); |
b20ce5e0 | 2496 | if (PageHuge(page)) |
dd78fedd KS |
2497 | return compound; |
2498 | ret = compound; | |
b20ce5e0 KS |
2499 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2500 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2501 | /* File pages has compound_mapcount included in _mapcount */ |
2502 | if (!PageAnon(page)) | |
2503 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2504 | if (PageDoubleMap(page)) |
2505 | ret -= HPAGE_PMD_NR; | |
2506 | return ret; | |
2507 | } | |
2508 | ||
6d0a07ed AA |
2509 | /* |
2510 | * This calculates accurately how many mappings a transparent hugepage | |
2511 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2512 | * accuracy is primarily needed to know if copy-on-write faults can | |
2513 | * reuse the page and change the mapping to read-write instead of | |
2514 | * copying them. At the same time this returns the total_mapcount too. | |
2515 | * | |
2516 | * The function returns the highest mapcount any one of the subpages | |
2517 | * has. If the return value is one, even if different processes are | |
2518 | * mapping different subpages of the transparent hugepage, they can | |
2519 | * all reuse it, because each process is reusing a different subpage. | |
2520 | * | |
2521 | * The total_mapcount is instead counting all virtual mappings of the | |
2522 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2523 | * caller all mappings belong to the same "mm" and in turn the | |
2524 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2525 | * local one as no other process may be mapping any of the subpages. | |
2526 | * | |
2527 | * It would be more accurate to replace page_mapcount() with | |
2528 | * page_trans_huge_mapcount(), however we only use | |
2529 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2530 | * need full accuracy to avoid breaking page pinning, because | |
2531 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2532 | */ | |
2533 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2534 | { | |
2535 | int i, ret, _total_mapcount, mapcount; | |
2536 | ||
2537 | /* hugetlbfs shouldn't call it */ | |
2538 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2539 | ||
2540 | if (likely(!PageTransCompound(page))) { | |
2541 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2542 | if (total_mapcount) | |
2543 | *total_mapcount = mapcount; | |
2544 | return mapcount; | |
2545 | } | |
2546 | ||
2547 | page = compound_head(page); | |
2548 | ||
2549 | _total_mapcount = ret = 0; | |
2550 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2551 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2552 | ret = max(ret, mapcount); | |
2553 | _total_mapcount += mapcount; | |
2554 | } | |
2555 | if (PageDoubleMap(page)) { | |
2556 | ret -= 1; | |
2557 | _total_mapcount -= HPAGE_PMD_NR; | |
2558 | } | |
2559 | mapcount = compound_mapcount(page); | |
2560 | ret += mapcount; | |
2561 | _total_mapcount += mapcount; | |
2562 | if (total_mapcount) | |
2563 | *total_mapcount = _total_mapcount; | |
2564 | return ret; | |
2565 | } | |
2566 | ||
b8f593cd HY |
2567 | /* Racy check whether the huge page can be split */ |
2568 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2569 | { | |
2570 | int extra_pins; | |
2571 | ||
aa5dc07f | 2572 | /* Additional pins from page cache */ |
b8f593cd HY |
2573 | if (PageAnon(page)) |
2574 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2575 | else | |
2576 | extra_pins = HPAGE_PMD_NR; | |
2577 | if (pextra_pins) | |
2578 | *pextra_pins = extra_pins; | |
2579 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2580 | } | |
2581 | ||
e9b61f19 KS |
2582 | /* |
2583 | * This function splits huge page into normal pages. @page can point to any | |
2584 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2585 | * | |
2586 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2587 | * The huge page must be locked. | |
2588 | * | |
2589 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2590 | * | |
2591 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2592 | * the hugepage. | |
2593 | * | |
2594 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2595 | * they are not mapped. | |
2596 | * | |
2597 | * Returns 0 if the hugepage is split successfully. | |
2598 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2599 | * us. | |
2600 | */ | |
2601 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2602 | { | |
2603 | struct page *head = compound_head(page); | |
a3d0a918 | 2604 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2605 | struct anon_vma *anon_vma = NULL; |
2606 | struct address_space *mapping = NULL; | |
2607 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2608 | bool mlocked; |
0b9b6fff | 2609 | unsigned long flags; |
006d3ff2 | 2610 | pgoff_t end; |
e9b61f19 KS |
2611 | |
2612 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2613 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2614 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2615 | ||
59807685 HY |
2616 | if (PageWriteback(page)) |
2617 | return -EBUSY; | |
2618 | ||
baa355fd KS |
2619 | if (PageAnon(head)) { |
2620 | /* | |
2621 | * The caller does not necessarily hold an mmap_sem that would | |
2622 | * prevent the anon_vma disappearing so we first we take a | |
2623 | * reference to it and then lock the anon_vma for write. This | |
2624 | * is similar to page_lock_anon_vma_read except the write lock | |
2625 | * is taken to serialise against parallel split or collapse | |
2626 | * operations. | |
2627 | */ | |
2628 | anon_vma = page_get_anon_vma(head); | |
2629 | if (!anon_vma) { | |
2630 | ret = -EBUSY; | |
2631 | goto out; | |
2632 | } | |
006d3ff2 | 2633 | end = -1; |
baa355fd KS |
2634 | mapping = NULL; |
2635 | anon_vma_lock_write(anon_vma); | |
2636 | } else { | |
2637 | mapping = head->mapping; | |
2638 | ||
2639 | /* Truncated ? */ | |
2640 | if (!mapping) { | |
2641 | ret = -EBUSY; | |
2642 | goto out; | |
2643 | } | |
2644 | ||
baa355fd KS |
2645 | anon_vma = NULL; |
2646 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2647 | |
2648 | /* | |
2649 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2650 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2651 | * which cannot be nested inside the page tree lock. So note | |
2652 | * end now: i_size itself may be changed at any moment, but | |
2653 | * head page lock is good enough to serialize the trimming. | |
2654 | */ | |
2655 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2656 | } |
e9b61f19 KS |
2657 | |
2658 | /* | |
906f9cdf | 2659 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2660 | * split PMDs |
2661 | */ | |
b8f593cd | 2662 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2663 | ret = -EBUSY; |
2664 | goto out_unlock; | |
2665 | } | |
2666 | ||
d9654322 | 2667 | mlocked = PageMlocked(page); |
906f9cdf | 2668 | unmap_page(head); |
e9b61f19 KS |
2669 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2670 | ||
d9654322 KS |
2671 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2672 | if (mlocked) | |
2673 | lru_add_drain(); | |
2674 | ||
baa355fd | 2675 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2676 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2677 | |
2678 | if (mapping) { | |
aa5dc07f | 2679 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2680 | |
baa355fd | 2681 | /* |
aa5dc07f | 2682 | * Check if the head page is present in page cache. |
baa355fd KS |
2683 | * We assume all tail are present too, if head is there. |
2684 | */ | |
aa5dc07f MW |
2685 | xa_lock(&mapping->i_pages); |
2686 | if (xas_load(&xas) != head) | |
baa355fd KS |
2687 | goto fail; |
2688 | } | |
2689 | ||
0139aa7b | 2690 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2691 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2692 | count = page_count(head); |
2693 | mapcount = total_mapcount(head); | |
baa355fd | 2694 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2695 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2696 | pgdata->split_queue_len--; |
9a982250 KS |
2697 | list_del(page_deferred_list(head)); |
2698 | } | |
65c45377 | 2699 | if (mapping) |
11fb9989 | 2700 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd | 2701 | spin_unlock(&pgdata->split_queue_lock); |
006d3ff2 | 2702 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2703 | if (PageSwapCache(head)) { |
2704 | swp_entry_t entry = { .val = page_private(head) }; | |
2705 | ||
2706 | ret = split_swap_cluster(entry); | |
2707 | } else | |
2708 | ret = 0; | |
e9b61f19 | 2709 | } else { |
baa355fd KS |
2710 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2711 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2712 | mapcount, count); | |
2713 | if (PageTail(page)) | |
2714 | dump_page(head, NULL); | |
2715 | dump_page(page, "total_mapcount(head) > 0"); | |
2716 | BUG(); | |
2717 | } | |
2718 | spin_unlock(&pgdata->split_queue_lock); | |
2719 | fail: if (mapping) | |
b93b0163 | 2720 | xa_unlock(&mapping->i_pages); |
a52633d8 | 2721 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
906f9cdf | 2722 | remap_page(head); |
e9b61f19 KS |
2723 | ret = -EBUSY; |
2724 | } | |
2725 | ||
2726 | out_unlock: | |
baa355fd KS |
2727 | if (anon_vma) { |
2728 | anon_vma_unlock_write(anon_vma); | |
2729 | put_anon_vma(anon_vma); | |
2730 | } | |
2731 | if (mapping) | |
2732 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2733 | out: |
2734 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2735 | return ret; | |
2736 | } | |
9a982250 KS |
2737 | |
2738 | void free_transhuge_page(struct page *page) | |
2739 | { | |
a3d0a918 | 2740 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2741 | unsigned long flags; |
2742 | ||
a3d0a918 | 2743 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2744 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2745 | pgdata->split_queue_len--; |
9a982250 KS |
2746 | list_del(page_deferred_list(page)); |
2747 | } | |
a3d0a918 | 2748 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2749 | free_compound_page(page); |
2750 | } | |
2751 | ||
2752 | void deferred_split_huge_page(struct page *page) | |
2753 | { | |
a3d0a918 | 2754 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2755 | unsigned long flags; |
2756 | ||
2757 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2758 | ||
a3d0a918 | 2759 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2760 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2761 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2762 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2763 | pgdata->split_queue_len++; | |
9a982250 | 2764 | } |
a3d0a918 | 2765 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2766 | } |
2767 | ||
2768 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2769 | struct shrink_control *sc) | |
2770 | { | |
a3d0a918 | 2771 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
6aa7de05 | 2772 | return READ_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2773 | } |
2774 | ||
2775 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2776 | struct shrink_control *sc) | |
2777 | { | |
a3d0a918 | 2778 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2779 | unsigned long flags; |
2780 | LIST_HEAD(list), *pos, *next; | |
2781 | struct page *page; | |
2782 | int split = 0; | |
2783 | ||
a3d0a918 | 2784 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2785 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2786 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2787 | page = list_entry((void *)pos, struct page, mapping); |
2788 | page = compound_head(page); | |
e3ae1953 KS |
2789 | if (get_page_unless_zero(page)) { |
2790 | list_move(page_deferred_list(page), &list); | |
2791 | } else { | |
2792 | /* We lost race with put_compound_page() */ | |
9a982250 | 2793 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2794 | pgdata->split_queue_len--; |
9a982250 | 2795 | } |
e3ae1953 KS |
2796 | if (!--sc->nr_to_scan) |
2797 | break; | |
9a982250 | 2798 | } |
a3d0a918 | 2799 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2800 | |
2801 | list_for_each_safe(pos, next, &list) { | |
2802 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2803 | if (!trylock_page(page)) |
2804 | goto next; | |
9a982250 KS |
2805 | /* split_huge_page() removes page from list on success */ |
2806 | if (!split_huge_page(page)) | |
2807 | split++; | |
2808 | unlock_page(page); | |
fa41b900 | 2809 | next: |
9a982250 KS |
2810 | put_page(page); |
2811 | } | |
2812 | ||
a3d0a918 KS |
2813 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2814 | list_splice_tail(&list, &pgdata->split_queue); | |
2815 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2816 | |
cb8d68ec KS |
2817 | /* |
2818 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2819 | * This can happen if pages were freed under us. | |
2820 | */ | |
2821 | if (!split && list_empty(&pgdata->split_queue)) | |
2822 | return SHRINK_STOP; | |
2823 | return split; | |
9a982250 KS |
2824 | } |
2825 | ||
2826 | static struct shrinker deferred_split_shrinker = { | |
2827 | .count_objects = deferred_split_count, | |
2828 | .scan_objects = deferred_split_scan, | |
2829 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2830 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2831 | }; |
49071d43 KS |
2832 | |
2833 | #ifdef CONFIG_DEBUG_FS | |
2834 | static int split_huge_pages_set(void *data, u64 val) | |
2835 | { | |
2836 | struct zone *zone; | |
2837 | struct page *page; | |
2838 | unsigned long pfn, max_zone_pfn; | |
2839 | unsigned long total = 0, split = 0; | |
2840 | ||
2841 | if (val != 1) | |
2842 | return -EINVAL; | |
2843 | ||
2844 | for_each_populated_zone(zone) { | |
2845 | max_zone_pfn = zone_end_pfn(zone); | |
2846 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2847 | if (!pfn_valid(pfn)) | |
2848 | continue; | |
2849 | ||
2850 | page = pfn_to_page(pfn); | |
2851 | if (!get_page_unless_zero(page)) | |
2852 | continue; | |
2853 | ||
2854 | if (zone != page_zone(page)) | |
2855 | goto next; | |
2856 | ||
baa355fd | 2857 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2858 | goto next; |
2859 | ||
2860 | total++; | |
2861 | lock_page(page); | |
2862 | if (!split_huge_page(page)) | |
2863 | split++; | |
2864 | unlock_page(page); | |
2865 | next: | |
2866 | put_page(page); | |
2867 | } | |
2868 | } | |
2869 | ||
145bdaa1 | 2870 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2871 | |
2872 | return 0; | |
2873 | } | |
2874 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2875 | "%llu\n"); | |
2876 | ||
2877 | static int __init split_huge_pages_debugfs(void) | |
2878 | { | |
2879 | void *ret; | |
2880 | ||
145bdaa1 | 2881 | ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
49071d43 KS |
2882 | &split_huge_pages_fops); |
2883 | if (!ret) | |
2884 | pr_warn("Failed to create split_huge_pages in debugfs"); | |
2885 | return 0; | |
2886 | } | |
2887 | late_initcall(split_huge_pages_debugfs); | |
2888 | #endif | |
616b8371 ZY |
2889 | |
2890 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2891 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2892 | struct page *page) | |
2893 | { | |
2894 | struct vm_area_struct *vma = pvmw->vma; | |
2895 | struct mm_struct *mm = vma->vm_mm; | |
2896 | unsigned long address = pvmw->address; | |
2897 | pmd_t pmdval; | |
2898 | swp_entry_t entry; | |
ab6e3d09 | 2899 | pmd_t pmdswp; |
616b8371 ZY |
2900 | |
2901 | if (!(pvmw->pmd && !pvmw->pte)) | |
2902 | return; | |
2903 | ||
616b8371 ZY |
2904 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
2905 | pmdval = *pvmw->pmd; | |
2906 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2907 | if (pmd_dirty(pmdval)) | |
2908 | set_page_dirty(page); | |
2909 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2910 | pmdswp = swp_entry_to_pmd(entry); |
2911 | if (pmd_soft_dirty(pmdval)) | |
2912 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2913 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2914 | page_remove_rmap(page, true); |
2915 | put_page(page); | |
616b8371 ZY |
2916 | } |
2917 | ||
2918 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2919 | { | |
2920 | struct vm_area_struct *vma = pvmw->vma; | |
2921 | struct mm_struct *mm = vma->vm_mm; | |
2922 | unsigned long address = pvmw->address; | |
2923 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2924 | pmd_t pmde; | |
2925 | swp_entry_t entry; | |
2926 | ||
2927 | if (!(pvmw->pmd && !pvmw->pte)) | |
2928 | return; | |
2929 | ||
2930 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2931 | get_page(new); | |
2932 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2933 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2934 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 2935 | if (is_write_migration_entry(entry)) |
f55e1014 | 2936 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
2937 | |
2938 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
2939 | if (PageAnon(new)) |
2940 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2941 | else | |
2942 | page_add_file_rmap(new, true); | |
616b8371 | 2943 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 2944 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
2945 | mlock_vma_page(new); |
2946 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
2947 | } | |
2948 | #endif |