Commit | Line | Data |
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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
ae3a8c1c AM |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | ||
71e3aac0 AA |
10 | #include <linux/mm.h> |
11 | #include <linux/sched.h> | |
f7ccbae4 | 12 | #include <linux/sched/coredump.h> |
6a3827d7 | 13 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
14 | #include <linux/highmem.h> |
15 | #include <linux/hugetlb.h> | |
16 | #include <linux/mmu_notifier.h> | |
17 | #include <linux/rmap.h> | |
18 | #include <linux/swap.h> | |
97ae1749 | 19 | #include <linux/shrinker.h> |
ba76149f | 20 | #include <linux/mm_inline.h> |
e9b61f19 | 21 | #include <linux/swapops.h> |
4897c765 | 22 | #include <linux/dax.h> |
ba76149f | 23 | #include <linux/khugepaged.h> |
878aee7d | 24 | #include <linux/freezer.h> |
f25748e3 | 25 | #include <linux/pfn_t.h> |
a664b2d8 | 26 | #include <linux/mman.h> |
3565fce3 | 27 | #include <linux/memremap.h> |
325adeb5 | 28 | #include <linux/pagemap.h> |
49071d43 | 29 | #include <linux/debugfs.h> |
4daae3b4 | 30 | #include <linux/migrate.h> |
43b5fbbd | 31 | #include <linux/hashtable.h> |
6b251fc9 | 32 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 33 | #include <linux/page_idle.h> |
baa355fd | 34 | #include <linux/shmem_fs.h> |
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 | */ | |
79553da2 | 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 | { | |
486 | /* | |
487 | * ->lru in the tail pages is occupied by compound_head. | |
488 | * Let's use ->mapping + ->index in the second tail page as list_head. | |
489 | */ | |
490 | return (struct list_head *)&page[2].mapping; | |
491 | } | |
492 | ||
493 | void prep_transhuge_page(struct page *page) | |
494 | { | |
495 | /* | |
496 | * we use page->mapping and page->indexlru in second tail page | |
497 | * as list_head: assuming THP order >= 2 | |
498 | */ | |
9a982250 KS |
499 | |
500 | INIT_LIST_HEAD(page_deferred_list(page)); | |
501 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
502 | } | |
503 | ||
74d2fad1 TK |
504 | unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
505 | loff_t off, unsigned long flags, unsigned long size) | |
506 | { | |
507 | unsigned long addr; | |
508 | loff_t off_end = off + len; | |
509 | loff_t off_align = round_up(off, size); | |
510 | unsigned long len_pad; | |
511 | ||
512 | if (off_end <= off_align || (off_end - off_align) < size) | |
513 | return 0; | |
514 | ||
515 | len_pad = len + size; | |
516 | if (len_pad < len || (off + len_pad) < off) | |
517 | return 0; | |
518 | ||
519 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
520 | off >> PAGE_SHIFT, flags); | |
521 | if (IS_ERR_VALUE(addr)) | |
522 | return 0; | |
523 | ||
524 | addr += (off - addr) & (size - 1); | |
525 | return addr; | |
526 | } | |
527 | ||
528 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
529 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
530 | { | |
531 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
532 | ||
533 | if (addr) | |
534 | goto out; | |
535 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
536 | goto out; | |
537 | ||
538 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
539 | if (addr) | |
540 | return addr; | |
541 | ||
542 | out: | |
543 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
544 | } | |
545 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
546 | ||
82b0f8c3 | 547 | static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, |
bae473a4 | 548 | gfp_t gfp) |
71e3aac0 | 549 | { |
82b0f8c3 | 550 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 551 | struct mem_cgroup *memcg; |
71e3aac0 | 552 | pgtable_t pgtable; |
82b0f8c3 | 553 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
6b31d595 | 554 | int ret = 0; |
71e3aac0 | 555 | |
309381fe | 556 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 557 | |
9d3c3354 DR |
558 | if (mem_cgroup_try_charge(page, vma->vm_mm, gfp | __GFP_NORETRY, &memcg, |
559 | true)) { | |
6b251fc9 AA |
560 | put_page(page); |
561 | count_vm_event(THP_FAULT_FALLBACK); | |
562 | return VM_FAULT_FALLBACK; | |
563 | } | |
00501b53 | 564 | |
bae473a4 | 565 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
00501b53 | 566 | if (unlikely(!pgtable)) { |
6b31d595 MH |
567 | ret = VM_FAULT_OOM; |
568 | goto release; | |
00501b53 | 569 | } |
71e3aac0 | 570 | |
c79b57e4 | 571 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
572 | /* |
573 | * The memory barrier inside __SetPageUptodate makes sure that | |
574 | * clear_huge_page writes become visible before the set_pmd_at() | |
575 | * write. | |
576 | */ | |
71e3aac0 AA |
577 | __SetPageUptodate(page); |
578 | ||
82b0f8c3 JK |
579 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
580 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 581 | goto unlock_release; |
71e3aac0 AA |
582 | } else { |
583 | pmd_t entry; | |
6b251fc9 | 584 | |
6b31d595 MH |
585 | ret = check_stable_address_space(vma->vm_mm); |
586 | if (ret) | |
587 | goto unlock_release; | |
588 | ||
6b251fc9 AA |
589 | /* Deliver the page fault to userland */ |
590 | if (userfaultfd_missing(vma)) { | |
591 | int ret; | |
592 | ||
82b0f8c3 | 593 | spin_unlock(vmf->ptl); |
f627c2f5 | 594 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 595 | put_page(page); |
bae473a4 | 596 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 597 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
598 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
599 | return ret; | |
600 | } | |
601 | ||
3122359a | 602 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 603 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 604 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 605 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 606 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
607 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
608 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 609 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 610 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 611 | spin_unlock(vmf->ptl); |
6b251fc9 | 612 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 AA |
613 | } |
614 | ||
aa2e878e | 615 | return 0; |
6b31d595 MH |
616 | unlock_release: |
617 | spin_unlock(vmf->ptl); | |
618 | release: | |
619 | if (pgtable) | |
620 | pte_free(vma->vm_mm, pgtable); | |
621 | mem_cgroup_cancel_charge(page, memcg, true); | |
622 | put_page(page); | |
623 | return ret; | |
624 | ||
71e3aac0 AA |
625 | } |
626 | ||
444eb2a4 | 627 | /* |
21440d7e DR |
628 | * always: directly stall for all thp allocations |
629 | * defer: wake kswapd and fail if not immediately available | |
630 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
631 | * fail if not immediately available | |
632 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
633 | * available | |
634 | * never: never stall for any thp allocation | |
444eb2a4 MG |
635 | */ |
636 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) | |
637 | { | |
21440d7e | 638 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 639 | |
21440d7e | 640 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
25160354 | 641 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
21440d7e DR |
642 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
643 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; | |
644 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
645 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
646 | __GFP_KSWAPD_RECLAIM); | |
647 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
648 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
649 | 0); | |
25160354 | 650 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
651 | } |
652 | ||
c4088ebd | 653 | /* Caller must hold page table lock. */ |
d295e341 | 654 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 655 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 656 | struct page *zero_page) |
fc9fe822 KS |
657 | { |
658 | pmd_t entry; | |
7c414164 AM |
659 | if (!pmd_none(*pmd)) |
660 | return false; | |
5918d10a | 661 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 662 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
663 | if (pgtable) |
664 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 665 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 666 | mm_inc_nr_ptes(mm); |
7c414164 | 667 | return true; |
fc9fe822 KS |
668 | } |
669 | ||
82b0f8c3 | 670 | int do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 671 | { |
82b0f8c3 | 672 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 673 | gfp_t gfp; |
71e3aac0 | 674 | struct page *page; |
82b0f8c3 | 675 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 676 | |
128ec037 | 677 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 678 | return VM_FAULT_FALLBACK; |
128ec037 KS |
679 | if (unlikely(anon_vma_prepare(vma))) |
680 | return VM_FAULT_OOM; | |
6d50e60c | 681 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 682 | return VM_FAULT_OOM; |
82b0f8c3 | 683 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 684 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
685 | transparent_hugepage_use_zero_page()) { |
686 | pgtable_t pgtable; | |
687 | struct page *zero_page; | |
688 | bool set; | |
6b251fc9 | 689 | int ret; |
bae473a4 | 690 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
128ec037 | 691 | if (unlikely(!pgtable)) |
ba76149f | 692 | return VM_FAULT_OOM; |
6fcb52a5 | 693 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 694 | if (unlikely(!zero_page)) { |
bae473a4 | 695 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 696 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 697 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 698 | } |
82b0f8c3 | 699 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
700 | ret = 0; |
701 | set = false; | |
82b0f8c3 | 702 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
703 | ret = check_stable_address_space(vma->vm_mm); |
704 | if (ret) { | |
705 | spin_unlock(vmf->ptl); | |
706 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
707 | spin_unlock(vmf->ptl); |
708 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
709 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
710 | } else { | |
bae473a4 | 711 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
712 | haddr, vmf->pmd, zero_page); |
713 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
714 | set = true; |
715 | } | |
716 | } else | |
82b0f8c3 | 717 | spin_unlock(vmf->ptl); |
6fcb52a5 | 718 | if (!set) |
bae473a4 | 719 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 720 | return ret; |
71e3aac0 | 721 | } |
444eb2a4 | 722 | gfp = alloc_hugepage_direct_gfpmask(vma); |
077fcf11 | 723 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
724 | if (unlikely(!page)) { |
725 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 726 | return VM_FAULT_FALLBACK; |
128ec037 | 727 | } |
9a982250 | 728 | prep_transhuge_page(page); |
82b0f8c3 | 729 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
730 | } |
731 | ||
ae18d6dc | 732 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
733 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
734 | pgtable_t pgtable) | |
5cad465d MW |
735 | { |
736 | struct mm_struct *mm = vma->vm_mm; | |
737 | pmd_t entry; | |
738 | spinlock_t *ptl; | |
739 | ||
740 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
741 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
742 | if (pfn_t_devmap(pfn)) | |
743 | entry = pmd_mkdevmap(entry); | |
01871e59 | 744 | if (write) { |
f55e1014 LT |
745 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
746 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 747 | } |
3b6521f5 OH |
748 | |
749 | if (pgtable) { | |
750 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 751 | mm_inc_nr_ptes(mm); |
3b6521f5 OH |
752 | } |
753 | ||
01871e59 RZ |
754 | set_pmd_at(mm, addr, pmd, entry); |
755 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 756 | spin_unlock(ptl); |
5cad465d MW |
757 | } |
758 | ||
759 | int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, | |
f25748e3 | 760 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
761 | { |
762 | pgprot_t pgprot = vma->vm_page_prot; | |
3b6521f5 | 763 | pgtable_t pgtable = NULL; |
5cad465d MW |
764 | /* |
765 | * If we had pmd_special, we could avoid all these restrictions, | |
766 | * but we need to be consistent with PTEs and architectures that | |
767 | * can't support a 'special' bit. | |
768 | */ | |
769 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
770 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
771 | (VM_PFNMAP|VM_MIXEDMAP)); | |
772 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
f25748e3 | 773 | BUG_ON(!pfn_t_devmap(pfn)); |
5cad465d MW |
774 | |
775 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
776 | return VM_FAULT_SIGBUS; | |
308a047c | 777 | |
3b6521f5 OH |
778 | if (arch_needs_pgtable_deposit()) { |
779 | pgtable = pte_alloc_one(vma->vm_mm, addr); | |
780 | if (!pgtable) | |
781 | return VM_FAULT_OOM; | |
782 | } | |
783 | ||
308a047c BP |
784 | track_pfn_insert(vma, &pgprot, pfn); |
785 | ||
3b6521f5 | 786 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 787 | return VM_FAULT_NOPAGE; |
5cad465d | 788 | } |
dee41079 | 789 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 790 | |
a00cc7d9 | 791 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 792 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 793 | { |
f55e1014 | 794 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
795 | pud = pud_mkwrite(pud); |
796 | return pud; | |
797 | } | |
798 | ||
799 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
800 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
801 | { | |
802 | struct mm_struct *mm = vma->vm_mm; | |
803 | pud_t entry; | |
804 | spinlock_t *ptl; | |
805 | ||
806 | ptl = pud_lock(mm, pud); | |
807 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); | |
808 | if (pfn_t_devmap(pfn)) | |
809 | entry = pud_mkdevmap(entry); | |
810 | if (write) { | |
f55e1014 LT |
811 | entry = pud_mkyoung(pud_mkdirty(entry)); |
812 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
813 | } |
814 | set_pud_at(mm, addr, pud, entry); | |
815 | update_mmu_cache_pud(vma, addr, pud); | |
816 | spin_unlock(ptl); | |
817 | } | |
818 | ||
819 | int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
820 | pud_t *pud, pfn_t pfn, bool write) | |
821 | { | |
822 | pgprot_t pgprot = vma->vm_page_prot; | |
823 | /* | |
824 | * If we had pud_special, we could avoid all these restrictions, | |
825 | * but we need to be consistent with PTEs and architectures that | |
826 | * can't support a 'special' bit. | |
827 | */ | |
828 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
829 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
830 | (VM_PFNMAP|VM_MIXEDMAP)); | |
831 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
832 | BUG_ON(!pfn_t_devmap(pfn)); | |
833 | ||
834 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
835 | return VM_FAULT_SIGBUS; | |
836 | ||
837 | track_pfn_insert(vma, &pgprot, pfn); | |
838 | ||
839 | insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); | |
840 | return VM_FAULT_NOPAGE; | |
841 | } | |
842 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
843 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
844 | ||
3565fce3 | 845 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 846 | pmd_t *pmd, int flags) |
3565fce3 DW |
847 | { |
848 | pmd_t _pmd; | |
849 | ||
a8f97366 KS |
850 | _pmd = pmd_mkyoung(*pmd); |
851 | if (flags & FOLL_WRITE) | |
852 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 853 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 854 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
855 | update_mmu_cache_pmd(vma, addr, pmd); |
856 | } | |
857 | ||
858 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
859 | pmd_t *pmd, int flags) | |
860 | { | |
861 | unsigned long pfn = pmd_pfn(*pmd); | |
862 | struct mm_struct *mm = vma->vm_mm; | |
863 | struct dev_pagemap *pgmap; | |
864 | struct page *page; | |
865 | ||
866 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
867 | ||
8310d48b KF |
868 | /* |
869 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
870 | * not be in this function with `flags & FOLL_COW` set. | |
871 | */ | |
872 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
873 | ||
f6f37321 | 874 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
875 | return NULL; |
876 | ||
877 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
878 | /* pass */; | |
879 | else | |
880 | return NULL; | |
881 | ||
882 | if (flags & FOLL_TOUCH) | |
a8f97366 | 883 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
884 | |
885 | /* | |
886 | * device mapped pages can only be returned if the | |
887 | * caller will manage the page reference count. | |
888 | */ | |
889 | if (!(flags & FOLL_GET)) | |
890 | return ERR_PTR(-EEXIST); | |
891 | ||
892 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
893 | pgmap = get_dev_pagemap(pfn, NULL); | |
894 | if (!pgmap) | |
895 | return ERR_PTR(-EFAULT); | |
896 | page = pfn_to_page(pfn); | |
897 | get_page(page); | |
898 | put_dev_pagemap(pgmap); | |
899 | ||
900 | return page; | |
901 | } | |
902 | ||
71e3aac0 AA |
903 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
904 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
905 | struct vm_area_struct *vma) | |
906 | { | |
c4088ebd | 907 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
908 | struct page *src_page; |
909 | pmd_t pmd; | |
12c9d70b | 910 | pgtable_t pgtable = NULL; |
628d47ce | 911 | int ret = -ENOMEM; |
71e3aac0 | 912 | |
628d47ce KS |
913 | /* Skip if can be re-fill on fault */ |
914 | if (!vma_is_anonymous(vma)) | |
915 | return 0; | |
916 | ||
917 | pgtable = pte_alloc_one(dst_mm, addr); | |
918 | if (unlikely(!pgtable)) | |
919 | goto out; | |
71e3aac0 | 920 | |
c4088ebd KS |
921 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
922 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
923 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
924 | |
925 | ret = -EAGAIN; | |
926 | pmd = *src_pmd; | |
84c3fc4e ZY |
927 | |
928 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
929 | if (unlikely(is_swap_pmd(pmd))) { | |
930 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
931 | ||
932 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
933 | if (is_write_migration_entry(entry)) { | |
934 | make_migration_entry_read(&entry); | |
935 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
936 | if (pmd_swp_soft_dirty(*src_pmd)) |
937 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
938 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
939 | } | |
dd8a67f9 | 940 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 941 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 942 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
943 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
944 | ret = 0; | |
945 | goto out_unlock; | |
946 | } | |
947 | #endif | |
948 | ||
628d47ce | 949 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
950 | pte_free(dst_mm, pgtable); |
951 | goto out_unlock; | |
952 | } | |
fc9fe822 | 953 | /* |
c4088ebd | 954 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
955 | * under splitting since we don't split the page itself, only pmd to |
956 | * a page table. | |
957 | */ | |
958 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 959 | struct page *zero_page; |
97ae1749 KS |
960 | /* |
961 | * get_huge_zero_page() will never allocate a new page here, | |
962 | * since we already have a zero page to copy. It just takes a | |
963 | * reference. | |
964 | */ | |
6fcb52a5 | 965 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 966 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 967 | zero_page); |
fc9fe822 KS |
968 | ret = 0; |
969 | goto out_unlock; | |
970 | } | |
de466bd6 | 971 | |
628d47ce KS |
972 | src_page = pmd_page(pmd); |
973 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
974 | get_page(src_page); | |
975 | page_dup_rmap(src_page, true); | |
976 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 977 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 978 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
979 | |
980 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
981 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
982 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
983 | |
984 | ret = 0; | |
985 | out_unlock: | |
c4088ebd KS |
986 | spin_unlock(src_ptl); |
987 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
988 | out: |
989 | return ret; | |
990 | } | |
991 | ||
a00cc7d9 MW |
992 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
993 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 994 | pud_t *pud, int flags) |
a00cc7d9 MW |
995 | { |
996 | pud_t _pud; | |
997 | ||
a8f97366 KS |
998 | _pud = pud_mkyoung(*pud); |
999 | if (flags & FOLL_WRITE) | |
1000 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1001 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1002 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1003 | update_mmu_cache_pud(vma, addr, pud); |
1004 | } | |
1005 | ||
1006 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
1007 | pud_t *pud, int flags) | |
1008 | { | |
1009 | unsigned long pfn = pud_pfn(*pud); | |
1010 | struct mm_struct *mm = vma->vm_mm; | |
1011 | struct dev_pagemap *pgmap; | |
1012 | struct page *page; | |
1013 | ||
1014 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1015 | ||
f6f37321 | 1016 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1017 | return NULL; |
1018 | ||
1019 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1020 | /* pass */; | |
1021 | else | |
1022 | return NULL; | |
1023 | ||
1024 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1025 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1026 | |
1027 | /* | |
1028 | * device mapped pages can only be returned if the | |
1029 | * caller will manage the page reference count. | |
1030 | */ | |
1031 | if (!(flags & FOLL_GET)) | |
1032 | return ERR_PTR(-EEXIST); | |
1033 | ||
1034 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
1035 | pgmap = get_dev_pagemap(pfn, NULL); | |
1036 | if (!pgmap) | |
1037 | return ERR_PTR(-EFAULT); | |
1038 | page = pfn_to_page(pfn); | |
1039 | get_page(page); | |
1040 | put_dev_pagemap(pgmap); | |
1041 | ||
1042 | return page; | |
1043 | } | |
1044 | ||
1045 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1046 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1047 | struct vm_area_struct *vma) | |
1048 | { | |
1049 | spinlock_t *dst_ptl, *src_ptl; | |
1050 | pud_t pud; | |
1051 | int ret; | |
1052 | ||
1053 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1054 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1055 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1056 | ||
1057 | ret = -EAGAIN; | |
1058 | pud = *src_pud; | |
1059 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1060 | goto out_unlock; | |
1061 | ||
1062 | /* | |
1063 | * When page table lock is held, the huge zero pud should not be | |
1064 | * under splitting since we don't split the page itself, only pud to | |
1065 | * a page table. | |
1066 | */ | |
1067 | if (is_huge_zero_pud(pud)) { | |
1068 | /* No huge zero pud yet */ | |
1069 | } | |
1070 | ||
1071 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1072 | pud = pud_mkold(pud_wrprotect(pud)); | |
1073 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1074 | ||
1075 | ret = 0; | |
1076 | out_unlock: | |
1077 | spin_unlock(src_ptl); | |
1078 | spin_unlock(dst_ptl); | |
1079 | return ret; | |
1080 | } | |
1081 | ||
1082 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1083 | { | |
1084 | pud_t entry; | |
1085 | unsigned long haddr; | |
1086 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1087 | ||
1088 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1089 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1090 | goto unlock; | |
1091 | ||
1092 | entry = pud_mkyoung(orig_pud); | |
1093 | if (write) | |
1094 | entry = pud_mkdirty(entry); | |
1095 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1096 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1097 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1098 | ||
1099 | unlock: | |
1100 | spin_unlock(vmf->ptl); | |
1101 | } | |
1102 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1103 | ||
82b0f8c3 | 1104 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1105 | { |
1106 | pmd_t entry; | |
1107 | unsigned long haddr; | |
20f664aa | 1108 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1109 | |
82b0f8c3 JK |
1110 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1111 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1112 | goto unlock; |
1113 | ||
1114 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1115 | if (write) |
1116 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1117 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1118 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1119 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1120 | |
1121 | unlock: | |
82b0f8c3 | 1122 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1123 | } |
1124 | ||
82b0f8c3 | 1125 | static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, |
bae473a4 | 1126 | struct page *page) |
71e3aac0 | 1127 | { |
82b0f8c3 JK |
1128 | struct vm_area_struct *vma = vmf->vma; |
1129 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1130 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1131 | pgtable_t pgtable; |
1132 | pmd_t _pmd; | |
1133 | int ret = 0, i; | |
1134 | struct page **pages; | |
2ec74c3e SG |
1135 | unsigned long mmun_start; /* For mmu_notifiers */ |
1136 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1137 | |
1138 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1139 | GFP_KERNEL); | |
1140 | if (unlikely(!pages)) { | |
1141 | ret |= VM_FAULT_OOM; | |
1142 | goto out; | |
1143 | } | |
1144 | ||
1145 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1146 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1147 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1148 | if (unlikely(!pages[i] || |
bae473a4 KS |
1149 | mem_cgroup_try_charge(pages[i], vma->vm_mm, |
1150 | GFP_KERNEL, &memcg, false))) { | |
b9bbfbe3 | 1151 | if (pages[i]) |
71e3aac0 | 1152 | put_page(pages[i]); |
b9bbfbe3 | 1153 | while (--i >= 0) { |
00501b53 JW |
1154 | memcg = (void *)page_private(pages[i]); |
1155 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1156 | mem_cgroup_cancel_charge(pages[i], memcg, |
1157 | false); | |
b9bbfbe3 AA |
1158 | put_page(pages[i]); |
1159 | } | |
71e3aac0 AA |
1160 | kfree(pages); |
1161 | ret |= VM_FAULT_OOM; | |
1162 | goto out; | |
1163 | } | |
00501b53 | 1164 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1165 | } |
1166 | ||
1167 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1168 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1169 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1170 | __SetPageUptodate(pages[i]); |
1171 | cond_resched(); | |
1172 | } | |
1173 | ||
2ec74c3e SG |
1174 | mmun_start = haddr; |
1175 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1176 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1177 | |
82b0f8c3 JK |
1178 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1179 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1180 | goto out_free_pages; |
309381fe | 1181 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1182 | |
0f10851e JG |
1183 | /* |
1184 | * Leave pmd empty until pte is filled note we must notify here as | |
1185 | * concurrent CPU thread might write to new page before the call to | |
1186 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1187 | * device seeing memory write in different order than CPU. | |
1188 | * | |
1189 | * See Documentation/vm/mmu_notifier.txt | |
1190 | */ | |
82b0f8c3 | 1191 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1192 | |
82b0f8c3 | 1193 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1194 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1195 | |
1196 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1197 | pte_t entry; |
71e3aac0 AA |
1198 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1199 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1200 | memcg = (void *)page_private(pages[i]); |
1201 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1202 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1203 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1204 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1205 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1206 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1207 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1208 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1209 | } |
1210 | kfree(pages); | |
1211 | ||
71e3aac0 | 1212 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1213 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1214 | page_remove_rmap(page, true); |
82b0f8c3 | 1215 | spin_unlock(vmf->ptl); |
71e3aac0 | 1216 | |
4645b9fe JG |
1217 | /* |
1218 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1219 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1220 | */ | |
1221 | mmu_notifier_invalidate_range_only_end(vma->vm_mm, mmun_start, | |
1222 | mmun_end); | |
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); |
bae473a4 | 1232 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
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 | ||
82b0f8c3 | 1243 | int 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; |
2ec74c3e SG |
1249 | unsigned long mmun_start; /* For mmu_notifiers */ |
1250 | unsigned long mmun_end; /* For mmu_notifiers */ | |
3b363692 | 1251 | gfp_t huge_gfp; /* for allocation and charge */ |
bae473a4 | 1252 | int ret = 0; |
71e3aac0 | 1253 | |
82b0f8c3 | 1254 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1255 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1256 | if (is_huge_zero_pmd(orig_pmd)) |
1257 | goto alloc; | |
82b0f8c3 JK |
1258 | spin_lock(vmf->ptl); |
1259 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1260 | goto out_unlock; |
1261 | ||
1262 | page = pmd_page(orig_pmd); | |
309381fe | 1263 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1264 | /* |
1265 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1266 | * part. |
1f25fe20 | 1267 | */ |
ba3c4ce6 HY |
1268 | if (!trylock_page(page)) { |
1269 | get_page(page); | |
1270 | spin_unlock(vmf->ptl); | |
1271 | lock_page(page); | |
1272 | spin_lock(vmf->ptl); | |
1273 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1274 | unlock_page(page); | |
1275 | put_page(page); | |
1276 | goto out_unlock; | |
1277 | } | |
1278 | put_page(page); | |
1279 | } | |
1280 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1281 | pmd_t entry; |
1282 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1283 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1284 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1285 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1286 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1287 | unlock_page(page); |
71e3aac0 AA |
1288 | goto out_unlock; |
1289 | } | |
ba3c4ce6 | 1290 | unlock_page(page); |
ddc58f27 | 1291 | get_page(page); |
82b0f8c3 | 1292 | spin_unlock(vmf->ptl); |
93b4796d | 1293 | alloc: |
71e3aac0 | 1294 | if (transparent_hugepage_enabled(vma) && |
077fcf11 | 1295 | !transparent_hugepage_debug_cow()) { |
444eb2a4 | 1296 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
3b363692 | 1297 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); |
077fcf11 | 1298 | } else |
71e3aac0 AA |
1299 | new_page = NULL; |
1300 | ||
9a982250 KS |
1301 | if (likely(new_page)) { |
1302 | prep_transhuge_page(new_page); | |
1303 | } else { | |
eecc1e42 | 1304 | if (!page) { |
82b0f8c3 | 1305 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1306 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1307 | } else { |
82b0f8c3 | 1308 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1309 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1310 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1311 | ret |= VM_FAULT_FALLBACK; |
1312 | } | |
ddc58f27 | 1313 | put_page(page); |
93b4796d | 1314 | } |
17766dde | 1315 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1316 | goto out; |
1317 | } | |
1318 | ||
bae473a4 | 1319 | if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, |
9d3c3354 | 1320 | huge_gfp | __GFP_NORETRY, &memcg, true))) { |
b9bbfbe3 | 1321 | put_page(new_page); |
82b0f8c3 | 1322 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1323 | if (page) |
ddc58f27 | 1324 | put_page(page); |
9845cbbd | 1325 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1326 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1327 | goto out; |
1328 | } | |
1329 | ||
17766dde DR |
1330 | count_vm_event(THP_FAULT_ALLOC); |
1331 | ||
eecc1e42 | 1332 | if (!page) |
c79b57e4 | 1333 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d KS |
1334 | else |
1335 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1336 | __SetPageUptodate(new_page); |
1337 | ||
2ec74c3e SG |
1338 | mmun_start = haddr; |
1339 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1340 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
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 | */ | |
1375 | mmu_notifier_invalidate_range_only_end(vma->vm_mm, mmun_start, | |
1376 | mmun_end); | |
71e3aac0 AA |
1377 | out: |
1378 | return ret; | |
2ec74c3e | 1379 | out_unlock: |
82b0f8c3 | 1380 | spin_unlock(vmf->ptl); |
2ec74c3e | 1381 | return ret; |
71e3aac0 AA |
1382 | } |
1383 | ||
8310d48b KF |
1384 | /* |
1385 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1386 | * after we've gone through a COW cycle and they are dirty. | |
1387 | */ | |
1388 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1389 | { | |
f6f37321 | 1390 | return pmd_write(pmd) || |
8310d48b KF |
1391 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); |
1392 | } | |
1393 | ||
b676b293 | 1394 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1395 | unsigned long addr, |
1396 | pmd_t *pmd, | |
1397 | unsigned int flags) | |
1398 | { | |
b676b293 | 1399 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1400 | struct page *page = NULL; |
1401 | ||
c4088ebd | 1402 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1403 | |
8310d48b | 1404 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1405 | goto out; |
1406 | ||
85facf25 KS |
1407 | /* Avoid dumping huge zero page */ |
1408 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1409 | return ERR_PTR(-EFAULT); | |
1410 | ||
2b4847e7 | 1411 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1412 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1413 | goto out; |
1414 | ||
71e3aac0 | 1415 | page = pmd_page(*pmd); |
ca120cf6 | 1416 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1417 | if (flags & FOLL_TOUCH) |
a8f97366 | 1418 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1419 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1420 | /* |
1421 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1422 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1423 | * | |
9a73f61b KS |
1424 | * For anon THP: |
1425 | * | |
e90309c9 KS |
1426 | * In most cases the pmd is the only mapping of the page as we |
1427 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1428 | * writable private mappings in populate_vma_page_range(). | |
1429 | * | |
1430 | * The only scenario when we have the page shared here is if we | |
1431 | * mlocking read-only mapping shared over fork(). We skip | |
1432 | * mlocking such pages. | |
9a73f61b KS |
1433 | * |
1434 | * For file THP: | |
1435 | * | |
1436 | * We can expect PageDoubleMap() to be stable under page lock: | |
1437 | * for file pages we set it in page_add_file_rmap(), which | |
1438 | * requires page to be locked. | |
e90309c9 | 1439 | */ |
9a73f61b KS |
1440 | |
1441 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1442 | goto skip_mlock; | |
1443 | if (PageDoubleMap(page) || !page->mapping) | |
1444 | goto skip_mlock; | |
1445 | if (!trylock_page(page)) | |
1446 | goto skip_mlock; | |
1447 | lru_add_drain(); | |
1448 | if (page->mapping && !PageDoubleMap(page)) | |
1449 | mlock_vma_page(page); | |
1450 | unlock_page(page); | |
b676b293 | 1451 | } |
9a73f61b | 1452 | skip_mlock: |
71e3aac0 | 1453 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1454 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1455 | if (flags & FOLL_GET) |
ddc58f27 | 1456 | get_page(page); |
71e3aac0 AA |
1457 | |
1458 | out: | |
1459 | return page; | |
1460 | } | |
1461 | ||
d10e63f2 | 1462 | /* NUMA hinting page fault entry point for trans huge pmds */ |
82b0f8c3 | 1463 | int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1464 | { |
82b0f8c3 | 1465 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1466 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1467 | struct page *page; |
82b0f8c3 | 1468 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
8191acbd | 1469 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1470 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1471 | bool page_locked; |
1472 | bool migrated = false; | |
b191f9b1 | 1473 | bool was_writable; |
6688cc05 | 1474 | int flags = 0; |
d10e63f2 | 1475 | |
82b0f8c3 JK |
1476 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1477 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1478 | goto out_unlock; |
1479 | ||
de466bd6 MG |
1480 | /* |
1481 | * If there are potential migrations, wait for completion and retry | |
1482 | * without disrupting NUMA hinting information. Do not relock and | |
1483 | * check_same as the page may no longer be mapped. | |
1484 | */ | |
82b0f8c3 JK |
1485 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1486 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1487 | if (!get_page_unless_zero(page)) |
1488 | goto out_unlock; | |
82b0f8c3 | 1489 | spin_unlock(vmf->ptl); |
5d833062 | 1490 | wait_on_page_locked(page); |
3c226c63 | 1491 | put_page(page); |
de466bd6 MG |
1492 | goto out; |
1493 | } | |
1494 | ||
d10e63f2 | 1495 | page = pmd_page(pmd); |
a1a46184 | 1496 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1497 | page_nid = page_to_nid(page); |
90572890 | 1498 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1499 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1500 | if (page_nid == this_nid) { |
03c5a6e1 | 1501 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1502 | flags |= TNF_FAULT_LOCAL; |
1503 | } | |
4daae3b4 | 1504 | |
bea66fbd | 1505 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1506 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1507 | flags |= TNF_NO_GROUP; |
1508 | ||
ff9042b1 MG |
1509 | /* |
1510 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1511 | * page_table_lock if at all possible | |
1512 | */ | |
b8916634 MG |
1513 | page_locked = trylock_page(page); |
1514 | target_nid = mpol_misplaced(page, vma, haddr); | |
1515 | if (target_nid == -1) { | |
1516 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1517 | if (page_locked) |
b8916634 | 1518 | goto clear_pmdnuma; |
2b4847e7 | 1519 | } |
4daae3b4 | 1520 | |
de466bd6 | 1521 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1522 | if (!page_locked) { |
3c226c63 MR |
1523 | page_nid = -1; |
1524 | if (!get_page_unless_zero(page)) | |
1525 | goto out_unlock; | |
82b0f8c3 | 1526 | spin_unlock(vmf->ptl); |
b8916634 | 1527 | wait_on_page_locked(page); |
3c226c63 | 1528 | put_page(page); |
b8916634 MG |
1529 | goto out; |
1530 | } | |
1531 | ||
2b4847e7 MG |
1532 | /* |
1533 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1534 | * to serialises splits | |
1535 | */ | |
b8916634 | 1536 | get_page(page); |
82b0f8c3 | 1537 | spin_unlock(vmf->ptl); |
b8916634 | 1538 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1539 | |
c69307d5 | 1540 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1541 | spin_lock(vmf->ptl); |
1542 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1543 | unlock_page(page); |
1544 | put_page(page); | |
a54a407f | 1545 | page_nid = -1; |
4daae3b4 | 1546 | goto out_unlock; |
b32967ff | 1547 | } |
ff9042b1 | 1548 | |
c3a489ca MG |
1549 | /* Bail if we fail to protect against THP splits for any reason */ |
1550 | if (unlikely(!anon_vma)) { | |
1551 | put_page(page); | |
1552 | page_nid = -1; | |
1553 | goto clear_pmdnuma; | |
1554 | } | |
1555 | ||
8b1b436d PZ |
1556 | /* |
1557 | * Since we took the NUMA fault, we must have observed the !accessible | |
1558 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1559 | * modifying the page we're about to migrate. | |
1560 | * | |
1561 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1562 | * inc_tlb_flush_pending(). |
1563 | * | |
1564 | * We are not sure a pending tlb flush here is for a huge page | |
1565 | * mapping or not. Hence use the tlb range variant | |
8b1b436d PZ |
1566 | */ |
1567 | if (mm_tlb_flush_pending(vma->vm_mm)) | |
ccde85ba | 1568 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
8b1b436d | 1569 | |
a54a407f MG |
1570 | /* |
1571 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1572 | * and access rights restored. |
a54a407f | 1573 | */ |
82b0f8c3 | 1574 | spin_unlock(vmf->ptl); |
8b1b436d | 1575 | |
bae473a4 | 1576 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1577 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1578 | if (migrated) { |
1579 | flags |= TNF_MIGRATED; | |
8191acbd | 1580 | page_nid = target_nid; |
074c2381 MG |
1581 | } else |
1582 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1583 | |
8191acbd | 1584 | goto out; |
b32967ff | 1585 | clear_pmdnuma: |
a54a407f | 1586 | BUG_ON(!PageLocked(page)); |
288bc549 | 1587 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1588 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1589 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1590 | if (was_writable) |
1591 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1592 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1593 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1594 | unlock_page(page); |
d10e63f2 | 1595 | out_unlock: |
82b0f8c3 | 1596 | spin_unlock(vmf->ptl); |
b8916634 MG |
1597 | |
1598 | out: | |
1599 | if (anon_vma) | |
1600 | page_unlock_anon_vma_read(anon_vma); | |
1601 | ||
8191acbd | 1602 | if (page_nid != -1) |
82b0f8c3 | 1603 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1604 | flags); |
8191acbd | 1605 | |
d10e63f2 MG |
1606 | return 0; |
1607 | } | |
1608 | ||
319904ad HY |
1609 | /* |
1610 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1611 | * Otherwise, return false. | |
1612 | */ | |
1613 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1614 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1615 | { |
1616 | spinlock_t *ptl; | |
1617 | pmd_t orig_pmd; | |
1618 | struct page *page; | |
1619 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1620 | bool ret = false; |
b8d3c4c3 | 1621 | |
07e32661 AK |
1622 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1623 | ||
b6ec57f4 KS |
1624 | ptl = pmd_trans_huge_lock(pmd, vma); |
1625 | if (!ptl) | |
25eedabe | 1626 | goto out_unlocked; |
b8d3c4c3 MK |
1627 | |
1628 | orig_pmd = *pmd; | |
319904ad | 1629 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1630 | goto out; |
b8d3c4c3 | 1631 | |
84c3fc4e ZY |
1632 | if (unlikely(!pmd_present(orig_pmd))) { |
1633 | VM_BUG_ON(thp_migration_supported() && | |
1634 | !is_pmd_migration_entry(orig_pmd)); | |
1635 | goto out; | |
1636 | } | |
1637 | ||
b8d3c4c3 MK |
1638 | page = pmd_page(orig_pmd); |
1639 | /* | |
1640 | * If other processes are mapping this page, we couldn't discard | |
1641 | * the page unless they all do MADV_FREE so let's skip the page. | |
1642 | */ | |
1643 | if (page_mapcount(page) != 1) | |
1644 | goto out; | |
1645 | ||
1646 | if (!trylock_page(page)) | |
1647 | goto out; | |
1648 | ||
1649 | /* | |
1650 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1651 | * will deactivate only them. | |
1652 | */ | |
1653 | if (next - addr != HPAGE_PMD_SIZE) { | |
1654 | get_page(page); | |
1655 | spin_unlock(ptl); | |
9818b8cd | 1656 | split_huge_page(page); |
b8d3c4c3 | 1657 | unlock_page(page); |
bbf29ffc | 1658 | put_page(page); |
b8d3c4c3 MK |
1659 | goto out_unlocked; |
1660 | } | |
1661 | ||
1662 | if (PageDirty(page)) | |
1663 | ClearPageDirty(page); | |
1664 | unlock_page(page); | |
1665 | ||
b8d3c4c3 | 1666 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1667 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1668 | orig_pmd = pmd_mkold(orig_pmd); |
1669 | orig_pmd = pmd_mkclean(orig_pmd); | |
1670 | ||
1671 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1672 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1673 | } | |
802a3a92 SL |
1674 | |
1675 | mark_page_lazyfree(page); | |
319904ad | 1676 | ret = true; |
b8d3c4c3 MK |
1677 | out: |
1678 | spin_unlock(ptl); | |
1679 | out_unlocked: | |
1680 | return ret; | |
1681 | } | |
1682 | ||
953c66c2 AK |
1683 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1684 | { | |
1685 | pgtable_t pgtable; | |
1686 | ||
1687 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1688 | pte_free(mm, pgtable); | |
c4812909 | 1689 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1690 | } |
1691 | ||
71e3aac0 | 1692 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1693 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1694 | { |
da146769 | 1695 | pmd_t orig_pmd; |
bf929152 | 1696 | spinlock_t *ptl; |
71e3aac0 | 1697 | |
07e32661 AK |
1698 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1699 | ||
b6ec57f4 KS |
1700 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1701 | if (!ptl) | |
da146769 KS |
1702 | return 0; |
1703 | /* | |
1704 | * For architectures like ppc64 we look at deposited pgtable | |
1705 | * when calling pmdp_huge_get_and_clear. So do the | |
1706 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1707 | * operations. | |
1708 | */ | |
1709 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1710 | tlb->fullmm); | |
1711 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1712 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1713 | if (arch_needs_pgtable_deposit()) |
1714 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1715 | spin_unlock(ptl); |
1716 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1717 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1718 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1719 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1720 | spin_unlock(ptl); |
c0f2e176 | 1721 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1722 | } else { |
616b8371 ZY |
1723 | struct page *page = NULL; |
1724 | int flush_needed = 1; | |
1725 | ||
1726 | if (pmd_present(orig_pmd)) { | |
1727 | page = pmd_page(orig_pmd); | |
1728 | page_remove_rmap(page, true); | |
1729 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1730 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1731 | } else if (thp_migration_supported()) { | |
1732 | swp_entry_t entry; | |
1733 | ||
1734 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1735 | entry = pmd_to_swp_entry(orig_pmd); | |
1736 | page = pfn_to_page(swp_offset(entry)); | |
1737 | flush_needed = 0; | |
1738 | } else | |
1739 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1740 | ||
b5072380 | 1741 | if (PageAnon(page)) { |
c14a6eb4 | 1742 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1743 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1744 | } else { | |
953c66c2 AK |
1745 | if (arch_needs_pgtable_deposit()) |
1746 | zap_deposited_table(tlb->mm, pmd); | |
b5072380 KS |
1747 | add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); |
1748 | } | |
616b8371 | 1749 | |
da146769 | 1750 | spin_unlock(ptl); |
616b8371 ZY |
1751 | if (flush_needed) |
1752 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1753 | } |
da146769 | 1754 | return 1; |
71e3aac0 AA |
1755 | } |
1756 | ||
1dd38b6c AK |
1757 | #ifndef pmd_move_must_withdraw |
1758 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1759 | spinlock_t *old_pmd_ptl, | |
1760 | struct vm_area_struct *vma) | |
1761 | { | |
1762 | /* | |
1763 | * With split pmd lock we also need to move preallocated | |
1764 | * PTE page table if new_pmd is on different PMD page table. | |
1765 | * | |
1766 | * We also don't deposit and withdraw tables for file pages. | |
1767 | */ | |
1768 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1769 | } | |
1770 | #endif | |
1771 | ||
ab6e3d09 NH |
1772 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1773 | { | |
1774 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1775 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1776 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1777 | else if (pmd_present(pmd)) | |
1778 | pmd = pmd_mksoft_dirty(pmd); | |
1779 | #endif | |
1780 | return pmd; | |
1781 | } | |
1782 | ||
bf8616d5 | 1783 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1784 | unsigned long new_addr, unsigned long old_end, |
5d190420 | 1785 | pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) |
37a1c49a | 1786 | { |
bf929152 | 1787 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1788 | pmd_t pmd; |
37a1c49a | 1789 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1790 | bool force_flush = false; |
37a1c49a AA |
1791 | |
1792 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1793 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1794 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1795 | return false; |
37a1c49a AA |
1796 | |
1797 | /* | |
1798 | * The destination pmd shouldn't be established, free_pgtables() | |
1799 | * should have release it. | |
1800 | */ | |
1801 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1802 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1803 | return false; |
37a1c49a AA |
1804 | } |
1805 | ||
bf929152 KS |
1806 | /* |
1807 | * We don't have to worry about the ordering of src and dst | |
1808 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1809 | */ | |
b6ec57f4 KS |
1810 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1811 | if (old_ptl) { | |
bf929152 KS |
1812 | new_ptl = pmd_lockptr(mm, new_pmd); |
1813 | if (new_ptl != old_ptl) | |
1814 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1815 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
a2ce2666 AL |
1816 | if (pmd_present(pmd) && pmd_dirty(pmd)) |
1817 | force_flush = true; | |
025c5b24 | 1818 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1819 | |
1dd38b6c | 1820 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1821 | pgtable_t pgtable; |
3592806c KS |
1822 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1823 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1824 | } |
ab6e3d09 NH |
1825 | pmd = move_soft_dirty_pmd(pmd); |
1826 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
b3084f4d AK |
1827 | if (new_ptl != old_ptl) |
1828 | spin_unlock(new_ptl); | |
5d190420 AL |
1829 | if (force_flush) |
1830 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
1831 | else | |
1832 | *need_flush = true; | |
bf929152 | 1833 | spin_unlock(old_ptl); |
4b471e88 | 1834 | return true; |
37a1c49a | 1835 | } |
4b471e88 | 1836 | return false; |
37a1c49a AA |
1837 | } |
1838 | ||
f123d74a MG |
1839 | /* |
1840 | * Returns | |
1841 | * - 0 if PMD could not be locked | |
1842 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1843 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1844 | */ | |
cd7548ab | 1845 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1846 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1847 | { |
1848 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1849 | spinlock_t *ptl; |
0a85e51d KS |
1850 | pmd_t entry; |
1851 | bool preserve_write; | |
1852 | int ret; | |
cd7548ab | 1853 | |
b6ec57f4 | 1854 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1855 | if (!ptl) |
1856 | return 0; | |
e944fd67 | 1857 | |
0a85e51d KS |
1858 | preserve_write = prot_numa && pmd_write(*pmd); |
1859 | ret = 1; | |
e944fd67 | 1860 | |
84c3fc4e ZY |
1861 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1862 | if (is_swap_pmd(*pmd)) { | |
1863 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1864 | ||
1865 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1866 | if (is_write_migration_entry(entry)) { | |
1867 | pmd_t newpmd; | |
1868 | /* | |
1869 | * A protection check is difficult so | |
1870 | * just be safe and disable write | |
1871 | */ | |
1872 | make_migration_entry_read(&entry); | |
1873 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1874 | if (pmd_swp_soft_dirty(*pmd)) |
1875 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1876 | set_pmd_at(mm, addr, pmd, newpmd); |
1877 | } | |
1878 | goto unlock; | |
1879 | } | |
1880 | #endif | |
1881 | ||
0a85e51d KS |
1882 | /* |
1883 | * Avoid trapping faults against the zero page. The read-only | |
1884 | * data is likely to be read-cached on the local CPU and | |
1885 | * local/remote hits to the zero page are not interesting. | |
1886 | */ | |
1887 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1888 | goto unlock; | |
025c5b24 | 1889 | |
0a85e51d KS |
1890 | if (prot_numa && pmd_protnone(*pmd)) |
1891 | goto unlock; | |
1892 | ||
ced10803 KS |
1893 | /* |
1894 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1895 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1896 | * which is also under down_read(mmap_sem): | |
1897 | * | |
1898 | * CPU0: CPU1: | |
1899 | * change_huge_pmd(prot_numa=1) | |
1900 | * pmdp_huge_get_and_clear_notify() | |
1901 | * madvise_dontneed() | |
1902 | * zap_pmd_range() | |
1903 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1904 | * // skip the pmd | |
1905 | * set_pmd_at(); | |
1906 | * // pmd is re-established | |
1907 | * | |
1908 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1909 | * which may break userspace. | |
1910 | * | |
1911 | * pmdp_invalidate() is required to make sure we don't miss | |
1912 | * dirty/young flags set by hardware. | |
1913 | */ | |
a3cf988f | 1914 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1915 | |
0a85e51d KS |
1916 | entry = pmd_modify(entry, newprot); |
1917 | if (preserve_write) | |
1918 | entry = pmd_mk_savedwrite(entry); | |
1919 | ret = HPAGE_PMD_NR; | |
1920 | set_pmd_at(mm, addr, pmd, entry); | |
1921 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1922 | unlock: | |
1923 | spin_unlock(ptl); | |
025c5b24 NH |
1924 | return ret; |
1925 | } | |
1926 | ||
1927 | /* | |
8f19b0c0 | 1928 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1929 | * |
8f19b0c0 HY |
1930 | * Note that if it returns page table lock pointer, this routine returns without |
1931 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1932 | */ |
b6ec57f4 | 1933 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1934 | { |
b6ec57f4 KS |
1935 | spinlock_t *ptl; |
1936 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1937 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1938 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1939 | return ptl; |
1940 | spin_unlock(ptl); | |
1941 | return NULL; | |
cd7548ab JW |
1942 | } |
1943 | ||
a00cc7d9 MW |
1944 | /* |
1945 | * Returns true if a given pud maps a thp, false otherwise. | |
1946 | * | |
1947 | * Note that if it returns true, this routine returns without unlocking page | |
1948 | * table lock. So callers must unlock it. | |
1949 | */ | |
1950 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1951 | { | |
1952 | spinlock_t *ptl; | |
1953 | ||
1954 | ptl = pud_lock(vma->vm_mm, pud); | |
1955 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1956 | return ptl; | |
1957 | spin_unlock(ptl); | |
1958 | return NULL; | |
1959 | } | |
1960 | ||
1961 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1962 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1963 | pud_t *pud, unsigned long addr) | |
1964 | { | |
1965 | pud_t orig_pud; | |
1966 | spinlock_t *ptl; | |
1967 | ||
1968 | ptl = __pud_trans_huge_lock(pud, vma); | |
1969 | if (!ptl) | |
1970 | return 0; | |
1971 | /* | |
1972 | * For architectures like ppc64 we look at deposited pgtable | |
1973 | * when calling pudp_huge_get_and_clear. So do the | |
1974 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1975 | * operations. | |
1976 | */ | |
1977 | orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, | |
1978 | tlb->fullmm); | |
1979 | tlb_remove_pud_tlb_entry(tlb, pud, addr); | |
1980 | if (vma_is_dax(vma)) { | |
1981 | spin_unlock(ptl); | |
1982 | /* No zero page support yet */ | |
1983 | } else { | |
1984 | /* No support for anonymous PUD pages yet */ | |
1985 | BUG(); | |
1986 | } | |
1987 | return 1; | |
1988 | } | |
1989 | ||
1990 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1991 | unsigned long haddr) | |
1992 | { | |
1993 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1994 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1995 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1996 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1997 | ||
ce9311cf | 1998 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1999 | |
2000 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2001 | } | |
2002 | ||
2003 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2004 | unsigned long address) | |
2005 | { | |
2006 | spinlock_t *ptl; | |
2007 | struct mm_struct *mm = vma->vm_mm; | |
2008 | unsigned long haddr = address & HPAGE_PUD_MASK; | |
2009 | ||
2010 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PUD_SIZE); | |
2011 | ptl = pud_lock(mm, pud); | |
2012 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) | |
2013 | goto out; | |
2014 | __split_huge_pud_locked(vma, pud, haddr); | |
2015 | ||
2016 | out: | |
2017 | spin_unlock(ptl); | |
4645b9fe JG |
2018 | /* |
2019 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2020 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2021 | */ | |
2022 | mmu_notifier_invalidate_range_only_end(mm, haddr, haddr + | |
2023 | HPAGE_PUD_SIZE); | |
a00cc7d9 MW |
2024 | } |
2025 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2026 | ||
eef1b3ba KS |
2027 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2028 | unsigned long haddr, pmd_t *pmd) | |
2029 | { | |
2030 | struct mm_struct *mm = vma->vm_mm; | |
2031 | pgtable_t pgtable; | |
2032 | pmd_t _pmd; | |
2033 | int i; | |
2034 | ||
0f10851e JG |
2035 | /* |
2036 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2037 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2038 | * replacing a zero pmd write protected page with a zero pte write | |
2039 | * protected page. | |
2040 | * | |
2041 | * See Documentation/vm/mmu_notifier.txt | |
2042 | */ | |
2043 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2044 | |
2045 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2046 | pmd_populate(mm, &_pmd, pgtable); | |
2047 | ||
2048 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2049 | pte_t *pte, entry; | |
2050 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2051 | entry = pte_mkspecial(entry); | |
2052 | pte = pte_offset_map(&_pmd, haddr); | |
2053 | VM_BUG_ON(!pte_none(*pte)); | |
2054 | set_pte_at(mm, haddr, pte, entry); | |
2055 | pte_unmap(pte); | |
2056 | } | |
2057 | smp_wmb(); /* make pte visible before pmd */ | |
2058 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2059 | } |
2060 | ||
2061 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2062 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2063 | { |
2064 | struct mm_struct *mm = vma->vm_mm; | |
2065 | struct page *page; | |
2066 | pgtable_t pgtable; | |
423ac9af | 2067 | pmd_t old_pmd, _pmd; |
a3cf988f | 2068 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2069 | unsigned long addr; |
eef1b3ba KS |
2070 | int i; |
2071 | ||
2072 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2073 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2074 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2075 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2076 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2077 | |
2078 | count_vm_event(THP_SPLIT_PMD); | |
2079 | ||
d21b9e57 KS |
2080 | if (!vma_is_anonymous(vma)) { |
2081 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2082 | /* |
2083 | * We are going to unmap this huge page. So | |
2084 | * just go ahead and zap it | |
2085 | */ | |
2086 | if (arch_needs_pgtable_deposit()) | |
2087 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2088 | if (vma_is_dax(vma)) |
2089 | return; | |
2090 | page = pmd_page(_pmd); | |
2091 | if (!PageReferenced(page) && pmd_young(_pmd)) | |
2092 | SetPageReferenced(page); | |
2093 | page_remove_rmap(page, true); | |
2094 | put_page(page); | |
2095 | add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); | |
eef1b3ba KS |
2096 | return; |
2097 | } else if (is_huge_zero_pmd(*pmd)) { | |
4645b9fe JG |
2098 | /* |
2099 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2100 | * mmu_notifier_invalidate_range() see comments below inside | |
2101 | * __split_huge_pmd() ? | |
2102 | * | |
2103 | * We are going from a zero huge page write protected to zero | |
2104 | * small page also write protected so it does not seems useful | |
2105 | * to invalidate secondary mmu at this time. | |
2106 | */ | |
eef1b3ba KS |
2107 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2108 | } | |
2109 | ||
423ac9af AK |
2110 | /* |
2111 | * Up to this point the pmd is present and huge and userland has the | |
2112 | * whole access to the hugepage during the split (which happens in | |
2113 | * place). If we overwrite the pmd with the not-huge version pointing | |
2114 | * to the pte here (which of course we could if all CPUs were bug | |
2115 | * free), userland could trigger a small page size TLB miss on the | |
2116 | * small sized TLB while the hugepage TLB entry is still established in | |
2117 | * the huge TLB. Some CPU doesn't like that. | |
2118 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2119 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2120 | * only safe if the permission and cache attributes of the two entries | |
2121 | * loaded in the two TLB is identical (which should be the case here). | |
2122 | * But it is generally safer to never allow small and huge TLB entries | |
2123 | * for the same virtual address to be loaded simultaneously. So instead | |
2124 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2125 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2126 | * must remain set at all times on the pmd until the split is complete | |
2127 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2128 | * non-huge version of the pmd entry with pmd_populate. | |
2129 | */ | |
2130 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2131 | ||
84c3fc4e | 2132 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
423ac9af | 2133 | pmd_migration = is_pmd_migration_entry(old_pmd); |
84c3fc4e ZY |
2134 | if (pmd_migration) { |
2135 | swp_entry_t entry; | |
2136 | ||
423ac9af | 2137 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e ZY |
2138 | page = pfn_to_page(swp_offset(entry)); |
2139 | } else | |
2140 | #endif | |
423ac9af | 2141 | page = pmd_page(old_pmd); |
eef1b3ba | 2142 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2143 | page_ref_add(page, HPAGE_PMD_NR - 1); |
423ac9af AK |
2144 | if (pmd_dirty(old_pmd)) |
2145 | SetPageDirty(page); | |
2146 | write = pmd_write(old_pmd); | |
2147 | young = pmd_young(old_pmd); | |
2148 | soft_dirty = pmd_soft_dirty(old_pmd); | |
eef1b3ba | 2149 | |
423ac9af AK |
2150 | /* |
2151 | * Withdraw the table only after we mark the pmd entry invalid. | |
2152 | * This's critical for some architectures (Power). | |
2153 | */ | |
eef1b3ba KS |
2154 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2155 | pmd_populate(mm, &_pmd, pgtable); | |
2156 | ||
2ac015e2 | 2157 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2158 | pte_t entry, *pte; |
2159 | /* | |
2160 | * Note that NUMA hinting access restrictions are not | |
2161 | * transferred to avoid any possibility of altering | |
2162 | * permissions across VMAs. | |
2163 | */ | |
84c3fc4e | 2164 | if (freeze || pmd_migration) { |
ba988280 KS |
2165 | swp_entry_t swp_entry; |
2166 | swp_entry = make_migration_entry(page + i, write); | |
2167 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2168 | if (soft_dirty) |
2169 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2170 | } else { |
6d2329f8 | 2171 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2172 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2173 | if (!write) |
2174 | entry = pte_wrprotect(entry); | |
2175 | if (!young) | |
2176 | entry = pte_mkold(entry); | |
804dd150 AA |
2177 | if (soft_dirty) |
2178 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2179 | } |
2ac015e2 | 2180 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2181 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2182 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2183 | atomic_inc(&page[i]._mapcount); |
2184 | pte_unmap(pte); | |
2185 | } | |
2186 | ||
2187 | /* | |
2188 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2189 | * false-negative page_mapped(). | |
2190 | */ | |
2191 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2192 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2193 | atomic_inc(&page[i]._mapcount); | |
2194 | } | |
2195 | ||
2196 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2197 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2198 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2199 | if (TestClearPageDoubleMap(page)) { |
2200 | /* No need in mapcount reference anymore */ | |
2201 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2202 | atomic_dec(&page[i]._mapcount); | |
2203 | } | |
2204 | } | |
2205 | ||
2206 | smp_wmb(); /* make pte visible before pmd */ | |
2207 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2208 | |
2209 | if (freeze) { | |
2ac015e2 | 2210 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2211 | page_remove_rmap(page + i, false); |
2212 | put_page(page + i); | |
2213 | } | |
2214 | } | |
eef1b3ba KS |
2215 | } |
2216 | ||
2217 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2218 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2219 | { |
2220 | spinlock_t *ptl; | |
2221 | struct mm_struct *mm = vma->vm_mm; | |
2222 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
2223 | ||
2224 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
2225 | ptl = pmd_lock(mm, pmd); | |
33f4751e NH |
2226 | |
2227 | /* | |
2228 | * If caller asks to setup a migration entries, we need a page to check | |
2229 | * pmd against. Otherwise we can end up replacing wrong page. | |
2230 | */ | |
2231 | VM_BUG_ON(freeze && !page); | |
2232 | if (page && page != pmd_page(*pmd)) | |
2233 | goto out; | |
2234 | ||
5c7fb56e | 2235 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2236 | page = pmd_page(*pmd); |
5c7fb56e | 2237 | if (PageMlocked(page)) |
5f737714 | 2238 | clear_page_mlock(page); |
84c3fc4e | 2239 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2240 | goto out; |
fec89c10 | 2241 | __split_huge_pmd_locked(vma, pmd, haddr, freeze); |
e90309c9 | 2242 | out: |
eef1b3ba | 2243 | spin_unlock(ptl); |
4645b9fe JG |
2244 | /* |
2245 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2246 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2247 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2248 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2249 | * fault will trigger a flush_notify before pointing to a new page | |
2250 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2251 | * page in the meantime) | |
2252 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2253 | * to invalidate secondary tlb entry they are all still valid. | |
2254 | * any further changes to individual pte will notify. So no need | |
2255 | * to call mmu_notifier->invalidate_range() | |
2256 | */ | |
2257 | mmu_notifier_invalidate_range_only_end(mm, haddr, haddr + | |
2258 | HPAGE_PMD_SIZE); | |
eef1b3ba KS |
2259 | } |
2260 | ||
fec89c10 KS |
2261 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2262 | bool freeze, struct page *page) | |
94fcc585 | 2263 | { |
f72e7dcd | 2264 | pgd_t *pgd; |
c2febafc | 2265 | p4d_t *p4d; |
f72e7dcd | 2266 | pud_t *pud; |
94fcc585 AA |
2267 | pmd_t *pmd; |
2268 | ||
78ddc534 | 2269 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2270 | if (!pgd_present(*pgd)) |
2271 | return; | |
2272 | ||
c2febafc KS |
2273 | p4d = p4d_offset(pgd, address); |
2274 | if (!p4d_present(*p4d)) | |
2275 | return; | |
2276 | ||
2277 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2278 | if (!pud_present(*pud)) |
2279 | return; | |
2280 | ||
2281 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2282 | |
33f4751e | 2283 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2284 | } |
2285 | ||
e1b9996b | 2286 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2287 | unsigned long start, |
2288 | unsigned long end, | |
2289 | long adjust_next) | |
2290 | { | |
2291 | /* | |
2292 | * If the new start address isn't hpage aligned and it could | |
2293 | * previously contain an hugepage: check if we need to split | |
2294 | * an huge pmd. | |
2295 | */ | |
2296 | if (start & ~HPAGE_PMD_MASK && | |
2297 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2298 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2299 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2300 | |
2301 | /* | |
2302 | * If the new end address isn't hpage aligned and it could | |
2303 | * previously contain an hugepage: check if we need to split | |
2304 | * an huge pmd. | |
2305 | */ | |
2306 | if (end & ~HPAGE_PMD_MASK && | |
2307 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2308 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2309 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2310 | |
2311 | /* | |
2312 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2313 | * vm_next->vm_start isn't page aligned and it could previously | |
2314 | * contain an hugepage: check if we need to split an huge pmd. | |
2315 | */ | |
2316 | if (adjust_next > 0) { | |
2317 | struct vm_area_struct *next = vma->vm_next; | |
2318 | unsigned long nstart = next->vm_start; | |
2319 | nstart += adjust_next << PAGE_SHIFT; | |
2320 | if (nstart & ~HPAGE_PMD_MASK && | |
2321 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2322 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2323 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2324 | } |
2325 | } | |
e9b61f19 | 2326 | |
fec89c10 | 2327 | static void freeze_page(struct page *page) |
e9b61f19 | 2328 | { |
baa355fd | 2329 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2330 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2331 | bool unmap_success; |
e9b61f19 KS |
2332 | |
2333 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2334 | ||
baa355fd | 2335 | if (PageAnon(page)) |
b5ff8161 | 2336 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2337 | |
666e5a40 MK |
2338 | unmap_success = try_to_unmap(page, ttu_flags); |
2339 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2340 | } |
2341 | ||
fec89c10 | 2342 | static void unfreeze_page(struct page *page) |
e9b61f19 | 2343 | { |
fec89c10 | 2344 | int i; |
ace71a19 KS |
2345 | if (PageTransHuge(page)) { |
2346 | remove_migration_ptes(page, page, true); | |
2347 | } else { | |
2348 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2349 | remove_migration_ptes(page + i, page + i, true); | |
2350 | } | |
e9b61f19 KS |
2351 | } |
2352 | ||
8df651c7 | 2353 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2354 | struct lruvec *lruvec, struct list_head *list) |
2355 | { | |
e9b61f19 KS |
2356 | struct page *page_tail = head + tail; |
2357 | ||
8df651c7 | 2358 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2359 | |
2360 | /* | |
605ca5ed KK |
2361 | * Clone page flags before unfreezing refcount. |
2362 | * | |
2363 | * After successful get_page_unless_zero() might follow flags change, | |
2364 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2365 | */ |
e9b61f19 KS |
2366 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2367 | page_tail->flags |= (head->flags & | |
2368 | ((1L << PG_referenced) | | |
2369 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2370 | (1L << PG_swapcache) | |
e9b61f19 KS |
2371 | (1L << PG_mlocked) | |
2372 | (1L << PG_uptodate) | | |
2373 | (1L << PG_active) | | |
2374 | (1L << PG_locked) | | |
b8d3c4c3 MK |
2375 | (1L << PG_unevictable) | |
2376 | (1L << PG_dirty))); | |
e9b61f19 | 2377 | |
605ca5ed | 2378 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2379 | smp_wmb(); |
2380 | ||
605ca5ed KK |
2381 | /* |
2382 | * Clear PageTail before unfreezing page refcount. | |
2383 | * | |
2384 | * After successful get_page_unless_zero() might follow put_page() | |
2385 | * which needs correct compound_head(). | |
2386 | */ | |
e9b61f19 KS |
2387 | clear_compound_head(page_tail); |
2388 | ||
605ca5ed KK |
2389 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2390 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2391 | PageSwapCache(head))); | |
2392 | ||
e9b61f19 KS |
2393 | if (page_is_young(head)) |
2394 | set_page_young(page_tail); | |
2395 | if (page_is_idle(head)) | |
2396 | set_page_idle(page_tail); | |
2397 | ||
2398 | /* ->mapping in first tail page is compound_mapcount */ | |
9a982250 | 2399 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
e9b61f19 KS |
2400 | page_tail); |
2401 | page_tail->mapping = head->mapping; | |
2402 | ||
2403 | page_tail->index = head->index + tail; | |
2404 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); | |
2405 | lru_add_page_tail(head, page_tail, lruvec, list); | |
e9b61f19 KS |
2406 | } |
2407 | ||
baa355fd KS |
2408 | static void __split_huge_page(struct page *page, struct list_head *list, |
2409 | unsigned long flags) | |
e9b61f19 KS |
2410 | { |
2411 | struct page *head = compound_head(page); | |
2412 | struct zone *zone = page_zone(head); | |
2413 | struct lruvec *lruvec; | |
baa355fd | 2414 | pgoff_t end = -1; |
8df651c7 | 2415 | int i; |
e9b61f19 | 2416 | |
599d0c95 | 2417 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
2418 | |
2419 | /* complete memcg works before add pages to LRU */ | |
2420 | mem_cgroup_split_huge_fixup(head); | |
2421 | ||
baa355fd KS |
2422 | if (!PageAnon(page)) |
2423 | end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); | |
2424 | ||
2425 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { | |
8df651c7 | 2426 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2427 | /* Some pages can be beyond i_size: drop them from page cache */ |
2428 | if (head[i].index >= end) { | |
2429 | __ClearPageDirty(head + i); | |
2430 | __delete_from_page_cache(head + i, NULL); | |
800d8c63 KS |
2431 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2432 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2433 | put_page(head + i); |
2434 | } | |
2435 | } | |
e9b61f19 KS |
2436 | |
2437 | ClearPageCompound(head); | |
baa355fd KS |
2438 | /* See comment in __split_huge_page_tail() */ |
2439 | if (PageAnon(head)) { | |
38d8b4e6 HY |
2440 | /* Additional pin to radix tree of swap cache */ |
2441 | if (PageSwapCache(head)) | |
2442 | page_ref_add(head, 2); | |
2443 | else | |
2444 | page_ref_inc(head); | |
baa355fd KS |
2445 | } else { |
2446 | /* Additional pin to radix tree */ | |
2447 | page_ref_add(head, 2); | |
2448 | spin_unlock(&head->mapping->tree_lock); | |
2449 | } | |
2450 | ||
a52633d8 | 2451 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 2452 | |
fec89c10 | 2453 | unfreeze_page(head); |
e9b61f19 KS |
2454 | |
2455 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2456 | struct page *subpage = head + i; | |
2457 | if (subpage == page) | |
2458 | continue; | |
2459 | unlock_page(subpage); | |
2460 | ||
2461 | /* | |
2462 | * Subpages may be freed if there wasn't any mapping | |
2463 | * like if add_to_swap() is running on a lru page that | |
2464 | * had its mapping zapped. And freeing these pages | |
2465 | * requires taking the lru_lock so we do the put_page | |
2466 | * of the tail pages after the split is complete. | |
2467 | */ | |
2468 | put_page(subpage); | |
2469 | } | |
2470 | } | |
2471 | ||
b20ce5e0 KS |
2472 | int total_mapcount(struct page *page) |
2473 | { | |
dd78fedd | 2474 | int i, compound, ret; |
b20ce5e0 KS |
2475 | |
2476 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2477 | ||
2478 | if (likely(!PageCompound(page))) | |
2479 | return atomic_read(&page->_mapcount) + 1; | |
2480 | ||
dd78fedd | 2481 | compound = compound_mapcount(page); |
b20ce5e0 | 2482 | if (PageHuge(page)) |
dd78fedd KS |
2483 | return compound; |
2484 | ret = compound; | |
b20ce5e0 KS |
2485 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2486 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2487 | /* File pages has compound_mapcount included in _mapcount */ |
2488 | if (!PageAnon(page)) | |
2489 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2490 | if (PageDoubleMap(page)) |
2491 | ret -= HPAGE_PMD_NR; | |
2492 | return ret; | |
2493 | } | |
2494 | ||
6d0a07ed AA |
2495 | /* |
2496 | * This calculates accurately how many mappings a transparent hugepage | |
2497 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2498 | * accuracy is primarily needed to know if copy-on-write faults can | |
2499 | * reuse the page and change the mapping to read-write instead of | |
2500 | * copying them. At the same time this returns the total_mapcount too. | |
2501 | * | |
2502 | * The function returns the highest mapcount any one of the subpages | |
2503 | * has. If the return value is one, even if different processes are | |
2504 | * mapping different subpages of the transparent hugepage, they can | |
2505 | * all reuse it, because each process is reusing a different subpage. | |
2506 | * | |
2507 | * The total_mapcount is instead counting all virtual mappings of the | |
2508 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2509 | * caller all mappings belong to the same "mm" and in turn the | |
2510 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2511 | * local one as no other process may be mapping any of the subpages. | |
2512 | * | |
2513 | * It would be more accurate to replace page_mapcount() with | |
2514 | * page_trans_huge_mapcount(), however we only use | |
2515 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2516 | * need full accuracy to avoid breaking page pinning, because | |
2517 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2518 | */ | |
2519 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2520 | { | |
2521 | int i, ret, _total_mapcount, mapcount; | |
2522 | ||
2523 | /* hugetlbfs shouldn't call it */ | |
2524 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2525 | ||
2526 | if (likely(!PageTransCompound(page))) { | |
2527 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2528 | if (total_mapcount) | |
2529 | *total_mapcount = mapcount; | |
2530 | return mapcount; | |
2531 | } | |
2532 | ||
2533 | page = compound_head(page); | |
2534 | ||
2535 | _total_mapcount = ret = 0; | |
2536 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2537 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2538 | ret = max(ret, mapcount); | |
2539 | _total_mapcount += mapcount; | |
2540 | } | |
2541 | if (PageDoubleMap(page)) { | |
2542 | ret -= 1; | |
2543 | _total_mapcount -= HPAGE_PMD_NR; | |
2544 | } | |
2545 | mapcount = compound_mapcount(page); | |
2546 | ret += mapcount; | |
2547 | _total_mapcount += mapcount; | |
2548 | if (total_mapcount) | |
2549 | *total_mapcount = _total_mapcount; | |
2550 | return ret; | |
2551 | } | |
2552 | ||
b8f593cd HY |
2553 | /* Racy check whether the huge page can be split */ |
2554 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2555 | { | |
2556 | int extra_pins; | |
2557 | ||
2558 | /* Additional pins from radix tree */ | |
2559 | if (PageAnon(page)) | |
2560 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2561 | else | |
2562 | extra_pins = HPAGE_PMD_NR; | |
2563 | if (pextra_pins) | |
2564 | *pextra_pins = extra_pins; | |
2565 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2566 | } | |
2567 | ||
e9b61f19 KS |
2568 | /* |
2569 | * This function splits huge page into normal pages. @page can point to any | |
2570 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2571 | * | |
2572 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2573 | * The huge page must be locked. | |
2574 | * | |
2575 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2576 | * | |
2577 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2578 | * the hugepage. | |
2579 | * | |
2580 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2581 | * they are not mapped. | |
2582 | * | |
2583 | * Returns 0 if the hugepage is split successfully. | |
2584 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2585 | * us. | |
2586 | */ | |
2587 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2588 | { | |
2589 | struct page *head = compound_head(page); | |
a3d0a918 | 2590 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2591 | struct anon_vma *anon_vma = NULL; |
2592 | struct address_space *mapping = NULL; | |
2593 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2594 | bool mlocked; |
0b9b6fff | 2595 | unsigned long flags; |
e9b61f19 KS |
2596 | |
2597 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2598 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2599 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2600 | ||
59807685 HY |
2601 | if (PageWriteback(page)) |
2602 | return -EBUSY; | |
2603 | ||
baa355fd KS |
2604 | if (PageAnon(head)) { |
2605 | /* | |
2606 | * The caller does not necessarily hold an mmap_sem that would | |
2607 | * prevent the anon_vma disappearing so we first we take a | |
2608 | * reference to it and then lock the anon_vma for write. This | |
2609 | * is similar to page_lock_anon_vma_read except the write lock | |
2610 | * is taken to serialise against parallel split or collapse | |
2611 | * operations. | |
2612 | */ | |
2613 | anon_vma = page_get_anon_vma(head); | |
2614 | if (!anon_vma) { | |
2615 | ret = -EBUSY; | |
2616 | goto out; | |
2617 | } | |
baa355fd KS |
2618 | mapping = NULL; |
2619 | anon_vma_lock_write(anon_vma); | |
2620 | } else { | |
2621 | mapping = head->mapping; | |
2622 | ||
2623 | /* Truncated ? */ | |
2624 | if (!mapping) { | |
2625 | ret = -EBUSY; | |
2626 | goto out; | |
2627 | } | |
2628 | ||
baa355fd KS |
2629 | anon_vma = NULL; |
2630 | i_mmap_lock_read(mapping); | |
e9b61f19 | 2631 | } |
e9b61f19 KS |
2632 | |
2633 | /* | |
2634 | * Racy check if we can split the page, before freeze_page() will | |
2635 | * split PMDs | |
2636 | */ | |
b8f593cd | 2637 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2638 | ret = -EBUSY; |
2639 | goto out_unlock; | |
2640 | } | |
2641 | ||
d9654322 | 2642 | mlocked = PageMlocked(page); |
fec89c10 | 2643 | freeze_page(head); |
e9b61f19 KS |
2644 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2645 | ||
d9654322 KS |
2646 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2647 | if (mlocked) | |
2648 | lru_add_drain(); | |
2649 | ||
baa355fd | 2650 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2651 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2652 | |
2653 | if (mapping) { | |
2654 | void **pslot; | |
2655 | ||
2656 | spin_lock(&mapping->tree_lock); | |
2657 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
2658 | page_index(head)); | |
2659 | /* | |
2660 | * Check if the head page is present in radix tree. | |
2661 | * We assume all tail are present too, if head is there. | |
2662 | */ | |
2663 | if (radix_tree_deref_slot_protected(pslot, | |
2664 | &mapping->tree_lock) != head) | |
2665 | goto fail; | |
2666 | } | |
2667 | ||
0139aa7b | 2668 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2669 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2670 | count = page_count(head); |
2671 | mapcount = total_mapcount(head); | |
baa355fd | 2672 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2673 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2674 | pgdata->split_queue_len--; |
9a982250 KS |
2675 | list_del(page_deferred_list(head)); |
2676 | } | |
65c45377 | 2677 | if (mapping) |
11fb9989 | 2678 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd KS |
2679 | spin_unlock(&pgdata->split_queue_lock); |
2680 | __split_huge_page(page, list, flags); | |
59807685 HY |
2681 | if (PageSwapCache(head)) { |
2682 | swp_entry_t entry = { .val = page_private(head) }; | |
2683 | ||
2684 | ret = split_swap_cluster(entry); | |
2685 | } else | |
2686 | ret = 0; | |
e9b61f19 | 2687 | } else { |
baa355fd KS |
2688 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2689 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2690 | mapcount, count); | |
2691 | if (PageTail(page)) | |
2692 | dump_page(head, NULL); | |
2693 | dump_page(page, "total_mapcount(head) > 0"); | |
2694 | BUG(); | |
2695 | } | |
2696 | spin_unlock(&pgdata->split_queue_lock); | |
2697 | fail: if (mapping) | |
2698 | spin_unlock(&mapping->tree_lock); | |
a52633d8 | 2699 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
fec89c10 | 2700 | unfreeze_page(head); |
e9b61f19 KS |
2701 | ret = -EBUSY; |
2702 | } | |
2703 | ||
2704 | out_unlock: | |
baa355fd KS |
2705 | if (anon_vma) { |
2706 | anon_vma_unlock_write(anon_vma); | |
2707 | put_anon_vma(anon_vma); | |
2708 | } | |
2709 | if (mapping) | |
2710 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2711 | out: |
2712 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2713 | return ret; | |
2714 | } | |
9a982250 KS |
2715 | |
2716 | void free_transhuge_page(struct page *page) | |
2717 | { | |
a3d0a918 | 2718 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2719 | unsigned long flags; |
2720 | ||
a3d0a918 | 2721 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2722 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2723 | pgdata->split_queue_len--; |
9a982250 KS |
2724 | list_del(page_deferred_list(page)); |
2725 | } | |
a3d0a918 | 2726 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2727 | free_compound_page(page); |
2728 | } | |
2729 | ||
2730 | void deferred_split_huge_page(struct page *page) | |
2731 | { | |
a3d0a918 | 2732 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2733 | unsigned long flags; |
2734 | ||
2735 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2736 | ||
a3d0a918 | 2737 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2738 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2739 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2740 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2741 | pgdata->split_queue_len++; | |
9a982250 | 2742 | } |
a3d0a918 | 2743 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2744 | } |
2745 | ||
2746 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2747 | struct shrink_control *sc) | |
2748 | { | |
a3d0a918 | 2749 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
6aa7de05 | 2750 | return READ_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2751 | } |
2752 | ||
2753 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2754 | struct shrink_control *sc) | |
2755 | { | |
a3d0a918 | 2756 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2757 | unsigned long flags; |
2758 | LIST_HEAD(list), *pos, *next; | |
2759 | struct page *page; | |
2760 | int split = 0; | |
2761 | ||
a3d0a918 | 2762 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2763 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2764 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2765 | page = list_entry((void *)pos, struct page, mapping); |
2766 | page = compound_head(page); | |
e3ae1953 KS |
2767 | if (get_page_unless_zero(page)) { |
2768 | list_move(page_deferred_list(page), &list); | |
2769 | } else { | |
2770 | /* We lost race with put_compound_page() */ | |
9a982250 | 2771 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2772 | pgdata->split_queue_len--; |
9a982250 | 2773 | } |
e3ae1953 KS |
2774 | if (!--sc->nr_to_scan) |
2775 | break; | |
9a982250 | 2776 | } |
a3d0a918 | 2777 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2778 | |
2779 | list_for_each_safe(pos, next, &list) { | |
2780 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2781 | if (!trylock_page(page)) |
2782 | goto next; | |
9a982250 KS |
2783 | /* split_huge_page() removes page from list on success */ |
2784 | if (!split_huge_page(page)) | |
2785 | split++; | |
2786 | unlock_page(page); | |
fa41b900 | 2787 | next: |
9a982250 KS |
2788 | put_page(page); |
2789 | } | |
2790 | ||
a3d0a918 KS |
2791 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2792 | list_splice_tail(&list, &pgdata->split_queue); | |
2793 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2794 | |
cb8d68ec KS |
2795 | /* |
2796 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2797 | * This can happen if pages were freed under us. | |
2798 | */ | |
2799 | if (!split && list_empty(&pgdata->split_queue)) | |
2800 | return SHRINK_STOP; | |
2801 | return split; | |
9a982250 KS |
2802 | } |
2803 | ||
2804 | static struct shrinker deferred_split_shrinker = { | |
2805 | .count_objects = deferred_split_count, | |
2806 | .scan_objects = deferred_split_scan, | |
2807 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2808 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2809 | }; |
49071d43 KS |
2810 | |
2811 | #ifdef CONFIG_DEBUG_FS | |
2812 | static int split_huge_pages_set(void *data, u64 val) | |
2813 | { | |
2814 | struct zone *zone; | |
2815 | struct page *page; | |
2816 | unsigned long pfn, max_zone_pfn; | |
2817 | unsigned long total = 0, split = 0; | |
2818 | ||
2819 | if (val != 1) | |
2820 | return -EINVAL; | |
2821 | ||
2822 | for_each_populated_zone(zone) { | |
2823 | max_zone_pfn = zone_end_pfn(zone); | |
2824 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2825 | if (!pfn_valid(pfn)) | |
2826 | continue; | |
2827 | ||
2828 | page = pfn_to_page(pfn); | |
2829 | if (!get_page_unless_zero(page)) | |
2830 | continue; | |
2831 | ||
2832 | if (zone != page_zone(page)) | |
2833 | goto next; | |
2834 | ||
baa355fd | 2835 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2836 | goto next; |
2837 | ||
2838 | total++; | |
2839 | lock_page(page); | |
2840 | if (!split_huge_page(page)) | |
2841 | split++; | |
2842 | unlock_page(page); | |
2843 | next: | |
2844 | put_page(page); | |
2845 | } | |
2846 | } | |
2847 | ||
145bdaa1 | 2848 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2849 | |
2850 | return 0; | |
2851 | } | |
2852 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2853 | "%llu\n"); | |
2854 | ||
2855 | static int __init split_huge_pages_debugfs(void) | |
2856 | { | |
2857 | void *ret; | |
2858 | ||
145bdaa1 | 2859 | ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
49071d43 KS |
2860 | &split_huge_pages_fops); |
2861 | if (!ret) | |
2862 | pr_warn("Failed to create split_huge_pages in debugfs"); | |
2863 | return 0; | |
2864 | } | |
2865 | late_initcall(split_huge_pages_debugfs); | |
2866 | #endif | |
616b8371 ZY |
2867 | |
2868 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2869 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2870 | struct page *page) | |
2871 | { | |
2872 | struct vm_area_struct *vma = pvmw->vma; | |
2873 | struct mm_struct *mm = vma->vm_mm; | |
2874 | unsigned long address = pvmw->address; | |
2875 | pmd_t pmdval; | |
2876 | swp_entry_t entry; | |
ab6e3d09 | 2877 | pmd_t pmdswp; |
616b8371 ZY |
2878 | |
2879 | if (!(pvmw->pmd && !pvmw->pte)) | |
2880 | return; | |
2881 | ||
2882 | mmu_notifier_invalidate_range_start(mm, address, | |
2883 | address + HPAGE_PMD_SIZE); | |
2884 | ||
2885 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); | |
2886 | pmdval = *pvmw->pmd; | |
2887 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2888 | if (pmd_dirty(pmdval)) | |
2889 | set_page_dirty(page); | |
2890 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2891 | pmdswp = swp_entry_to_pmd(entry); |
2892 | if (pmd_soft_dirty(pmdval)) | |
2893 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2894 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2895 | page_remove_rmap(page, true); |
2896 | put_page(page); | |
2897 | ||
2898 | mmu_notifier_invalidate_range_end(mm, address, | |
2899 | address + HPAGE_PMD_SIZE); | |
2900 | } | |
2901 | ||
2902 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2903 | { | |
2904 | struct vm_area_struct *vma = pvmw->vma; | |
2905 | struct mm_struct *mm = vma->vm_mm; | |
2906 | unsigned long address = pvmw->address; | |
2907 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2908 | pmd_t pmde; | |
2909 | swp_entry_t entry; | |
2910 | ||
2911 | if (!(pvmw->pmd && !pvmw->pte)) | |
2912 | return; | |
2913 | ||
2914 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2915 | get_page(new); | |
2916 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2917 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2918 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 2919 | if (is_write_migration_entry(entry)) |
f55e1014 | 2920 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
2921 | |
2922 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
2923 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2924 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); | |
2925 | if (vma->vm_flags & VM_LOCKED) | |
2926 | mlock_vma_page(new); | |
2927 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
2928 | } | |
2929 | #endif |