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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> |
58eba200 | 36 | #include <linux/page_owner.h> |
97ae1749 | 37 | |
71e3aac0 AA |
38 | #include <asm/tlb.h> |
39 | #include <asm/pgalloc.h> | |
40 | #include "internal.h" | |
41 | ||
ba76149f | 42 | /* |
8bfa3f9a JW |
43 | * By default transparent hugepage support is disabled in order that avoid |
44 | * to risk increase the memory footprint of applications without a guaranteed | |
45 | * benefit. When transparent hugepage support is enabled, is for all mappings, | |
46 | * and khugepaged scans all mappings. | |
47 | * Defrag is invoked by khugepaged hugepage allocations and by page faults | |
48 | * for all hugepage allocations. | |
ba76149f | 49 | */ |
71e3aac0 | 50 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 51 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 52 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
53 | #endif |
54 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
55 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
56 | #endif | |
444eb2a4 | 57 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
58 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
59 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 60 | |
9a982250 | 61 | static struct shrinker deferred_split_shrinker; |
f000565a | 62 | |
97ae1749 | 63 | static atomic_t huge_zero_refcount; |
56873f43 | 64 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 65 | |
6fcb52a5 | 66 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
67 | { |
68 | struct page *zero_page; | |
69 | retry: | |
70 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 71 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
72 | |
73 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 74 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
75 | if (!zero_page) { |
76 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 77 | return NULL; |
d8a8e1f0 KS |
78 | } |
79 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 80 | preempt_disable(); |
5918d10a | 81 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 82 | preempt_enable(); |
5ddacbe9 | 83 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
84 | goto retry; |
85 | } | |
86 | ||
87 | /* We take additional reference here. It will be put back by shrinker */ | |
88 | atomic_set(&huge_zero_refcount, 2); | |
89 | preempt_enable(); | |
4db0c3c2 | 90 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
91 | } |
92 | ||
6fcb52a5 | 93 | static void put_huge_zero_page(void) |
4a6c1297 | 94 | { |
97ae1749 KS |
95 | /* |
96 | * Counter should never go to zero here. Only shrinker can put | |
97 | * last reference. | |
98 | */ | |
99 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
100 | } |
101 | ||
6fcb52a5 AL |
102 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
103 | { | |
104 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
105 | return READ_ONCE(huge_zero_page); | |
106 | ||
107 | if (!get_huge_zero_page()) | |
108 | return NULL; | |
109 | ||
110 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
111 | put_huge_zero_page(); | |
112 | ||
113 | return READ_ONCE(huge_zero_page); | |
114 | } | |
115 | ||
116 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
117 | { | |
118 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
119 | put_huge_zero_page(); | |
120 | } | |
121 | ||
48896466 GC |
122 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
123 | struct shrink_control *sc) | |
4a6c1297 | 124 | { |
48896466 GC |
125 | /* we can free zero page only if last reference remains */ |
126 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
127 | } | |
97ae1749 | 128 | |
48896466 GC |
129 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
130 | struct shrink_control *sc) | |
131 | { | |
97ae1749 | 132 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
133 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
134 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 135 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 136 | return HPAGE_PMD_NR; |
97ae1749 KS |
137 | } |
138 | ||
139 | return 0; | |
4a6c1297 KS |
140 | } |
141 | ||
97ae1749 | 142 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
143 | .count_objects = shrink_huge_zero_page_count, |
144 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
145 | .seeks = DEFAULT_SEEKS, |
146 | }; | |
147 | ||
71e3aac0 | 148 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
149 | static ssize_t enabled_show(struct kobject *kobj, |
150 | struct kobj_attribute *attr, char *buf) | |
151 | { | |
444eb2a4 MG |
152 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
153 | return sprintf(buf, "[always] madvise never\n"); | |
154 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
155 | return sprintf(buf, "always [madvise] never\n"); | |
156 | else | |
157 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 158 | } |
444eb2a4 | 159 | |
71e3aac0 AA |
160 | static ssize_t enabled_store(struct kobject *kobj, |
161 | struct kobj_attribute *attr, | |
162 | const char *buf, size_t count) | |
163 | { | |
21440d7e | 164 | ssize_t ret = count; |
ba76149f | 165 | |
2630ea39 | 166 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
167 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
168 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 169 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
170 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
171 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 172 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
173 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
174 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
175 | } else | |
176 | ret = -EINVAL; | |
ba76149f AA |
177 | |
178 | if (ret > 0) { | |
b46e756f | 179 | int err = start_stop_khugepaged(); |
ba76149f AA |
180 | if (err) |
181 | ret = err; | |
182 | } | |
ba76149f | 183 | return ret; |
71e3aac0 AA |
184 | } |
185 | static struct kobj_attribute enabled_attr = | |
186 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
187 | ||
b46e756f | 188 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
189 | struct kobj_attribute *attr, char *buf, |
190 | enum transparent_hugepage_flag flag) | |
191 | { | |
e27e6151 BH |
192 | return sprintf(buf, "%d\n", |
193 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 194 | } |
e27e6151 | 195 | |
b46e756f | 196 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
197 | struct kobj_attribute *attr, |
198 | const char *buf, size_t count, | |
199 | enum transparent_hugepage_flag flag) | |
200 | { | |
e27e6151 BH |
201 | unsigned long value; |
202 | int ret; | |
203 | ||
204 | ret = kstrtoul(buf, 10, &value); | |
205 | if (ret < 0) | |
206 | return ret; | |
207 | if (value > 1) | |
208 | return -EINVAL; | |
209 | ||
210 | if (value) | |
71e3aac0 | 211 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 212 | else |
71e3aac0 | 213 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
214 | |
215 | return count; | |
216 | } | |
217 | ||
71e3aac0 AA |
218 | static ssize_t defrag_show(struct kobject *kobj, |
219 | struct kobj_attribute *attr, char *buf) | |
220 | { | |
444eb2a4 | 221 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 222 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 223 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
224 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
225 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
226 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
227 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
228 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
229 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 230 | } |
21440d7e | 231 | |
71e3aac0 AA |
232 | static ssize_t defrag_store(struct kobject *kobj, |
233 | struct kobj_attribute *attr, | |
234 | const char *buf, size_t count) | |
235 | { | |
2630ea39 | 236 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
237 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
238 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
239 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
240 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 241 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
242 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
243 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
244 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
245 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 246 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
247 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
248 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
249 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
250 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 251 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
252 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
253 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
254 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
255 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
2630ea39 | 256 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
257 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
258 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
259 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
260 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
261 | } else | |
262 | return -EINVAL; | |
263 | ||
264 | return count; | |
71e3aac0 AA |
265 | } |
266 | static struct kobj_attribute defrag_attr = | |
267 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
268 | ||
79da5407 KS |
269 | static ssize_t use_zero_page_show(struct kobject *kobj, |
270 | struct kobj_attribute *attr, char *buf) | |
271 | { | |
b46e756f | 272 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
273 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
274 | } | |
275 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
276 | struct kobj_attribute *attr, const char *buf, size_t count) | |
277 | { | |
b46e756f | 278 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
279 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
280 | } | |
281 | static struct kobj_attribute use_zero_page_attr = | |
282 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
283 | |
284 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
285 | struct kobj_attribute *attr, char *buf) | |
286 | { | |
287 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
288 | } | |
289 | static struct kobj_attribute hpage_pmd_size_attr = | |
290 | __ATTR_RO(hpage_pmd_size); | |
291 | ||
71e3aac0 AA |
292 | #ifdef CONFIG_DEBUG_VM |
293 | static ssize_t debug_cow_show(struct kobject *kobj, | |
294 | struct kobj_attribute *attr, char *buf) | |
295 | { | |
b46e756f | 296 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
297 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
298 | } | |
299 | static ssize_t debug_cow_store(struct kobject *kobj, | |
300 | struct kobj_attribute *attr, | |
301 | const char *buf, size_t count) | |
302 | { | |
b46e756f | 303 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
304 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
305 | } | |
306 | static struct kobj_attribute debug_cow_attr = | |
307 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
308 | #endif /* CONFIG_DEBUG_VM */ | |
309 | ||
310 | static struct attribute *hugepage_attr[] = { | |
311 | &enabled_attr.attr, | |
312 | &defrag_attr.attr, | |
79da5407 | 313 | &use_zero_page_attr.attr, |
49920d28 | 314 | &hpage_pmd_size_attr.attr, |
e496cf3d | 315 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
316 | &shmem_enabled_attr.attr, |
317 | #endif | |
71e3aac0 AA |
318 | #ifdef CONFIG_DEBUG_VM |
319 | &debug_cow_attr.attr, | |
320 | #endif | |
321 | NULL, | |
322 | }; | |
323 | ||
8aa95a21 | 324 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 325 | .attrs = hugepage_attr, |
ba76149f AA |
326 | }; |
327 | ||
569e5590 | 328 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 329 | { |
71e3aac0 AA |
330 | int err; |
331 | ||
569e5590 SL |
332 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
333 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 334 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 335 | return -ENOMEM; |
ba76149f AA |
336 | } |
337 | ||
569e5590 | 338 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 339 | if (err) { |
ae3a8c1c | 340 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 341 | goto delete_obj; |
ba76149f AA |
342 | } |
343 | ||
569e5590 | 344 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 345 | if (err) { |
ae3a8c1c | 346 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 347 | goto remove_hp_group; |
ba76149f | 348 | } |
569e5590 SL |
349 | |
350 | return 0; | |
351 | ||
352 | remove_hp_group: | |
353 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
354 | delete_obj: | |
355 | kobject_put(*hugepage_kobj); | |
356 | return err; | |
357 | } | |
358 | ||
359 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
360 | { | |
361 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
362 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
363 | kobject_put(hugepage_kobj); | |
364 | } | |
365 | #else | |
366 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
367 | { | |
368 | return 0; | |
369 | } | |
370 | ||
371 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
372 | { | |
373 | } | |
374 | #endif /* CONFIG_SYSFS */ | |
375 | ||
376 | static int __init hugepage_init(void) | |
377 | { | |
378 | int err; | |
379 | struct kobject *hugepage_kobj; | |
380 | ||
381 | if (!has_transparent_hugepage()) { | |
382 | transparent_hugepage_flags = 0; | |
383 | return -EINVAL; | |
384 | } | |
385 | ||
ff20c2e0 KS |
386 | /* |
387 | * hugepages can't be allocated by the buddy allocator | |
388 | */ | |
389 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
390 | /* | |
391 | * we use page->mapping and page->index in second tail page | |
392 | * as list_head: assuming THP order >= 2 | |
393 | */ | |
394 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
395 | ||
569e5590 SL |
396 | err = hugepage_init_sysfs(&hugepage_kobj); |
397 | if (err) | |
65ebb64f | 398 | goto err_sysfs; |
ba76149f | 399 | |
b46e756f | 400 | err = khugepaged_init(); |
ba76149f | 401 | if (err) |
65ebb64f | 402 | goto err_slab; |
ba76149f | 403 | |
65ebb64f KS |
404 | err = register_shrinker(&huge_zero_page_shrinker); |
405 | if (err) | |
406 | goto err_hzp_shrinker; | |
9a982250 KS |
407 | err = register_shrinker(&deferred_split_shrinker); |
408 | if (err) | |
409 | goto err_split_shrinker; | |
97ae1749 | 410 | |
97562cd2 RR |
411 | /* |
412 | * By default disable transparent hugepages on smaller systems, | |
413 | * where the extra memory used could hurt more than TLB overhead | |
414 | * is likely to save. The admin can still enable it through /sys. | |
415 | */ | |
79553da2 | 416 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 417 | transparent_hugepage_flags = 0; |
79553da2 KS |
418 | return 0; |
419 | } | |
97562cd2 | 420 | |
79553da2 | 421 | err = start_stop_khugepaged(); |
65ebb64f KS |
422 | if (err) |
423 | goto err_khugepaged; | |
ba76149f | 424 | |
569e5590 | 425 | return 0; |
65ebb64f | 426 | err_khugepaged: |
9a982250 KS |
427 | unregister_shrinker(&deferred_split_shrinker); |
428 | err_split_shrinker: | |
65ebb64f KS |
429 | unregister_shrinker(&huge_zero_page_shrinker); |
430 | err_hzp_shrinker: | |
b46e756f | 431 | khugepaged_destroy(); |
65ebb64f | 432 | err_slab: |
569e5590 | 433 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 434 | err_sysfs: |
ba76149f | 435 | return err; |
71e3aac0 | 436 | } |
a64fb3cd | 437 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
438 | |
439 | static int __init setup_transparent_hugepage(char *str) | |
440 | { | |
441 | int ret = 0; | |
442 | if (!str) | |
443 | goto out; | |
444 | if (!strcmp(str, "always")) { | |
445 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
446 | &transparent_hugepage_flags); | |
447 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
448 | &transparent_hugepage_flags); | |
449 | ret = 1; | |
450 | } else if (!strcmp(str, "madvise")) { | |
451 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
452 | &transparent_hugepage_flags); | |
453 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
454 | &transparent_hugepage_flags); | |
455 | ret = 1; | |
456 | } else if (!strcmp(str, "never")) { | |
457 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
458 | &transparent_hugepage_flags); | |
459 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
460 | &transparent_hugepage_flags); | |
461 | ret = 1; | |
462 | } | |
463 | out: | |
464 | if (!ret) | |
ae3a8c1c | 465 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
466 | return ret; |
467 | } | |
468 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
469 | ||
b32967ff | 470 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
471 | { |
472 | if (likely(vma->vm_flags & VM_WRITE)) | |
473 | pmd = pmd_mkwrite(pmd); | |
474 | return pmd; | |
475 | } | |
476 | ||
9a982250 KS |
477 | static inline struct list_head *page_deferred_list(struct page *page) |
478 | { | |
479 | /* | |
480 | * ->lru in the tail pages is occupied by compound_head. | |
481 | * Let's use ->mapping + ->index in the second tail page as list_head. | |
482 | */ | |
483 | return (struct list_head *)&page[2].mapping; | |
484 | } | |
485 | ||
486 | void prep_transhuge_page(struct page *page) | |
487 | { | |
488 | /* | |
489 | * we use page->mapping and page->indexlru in second tail page | |
490 | * as list_head: assuming THP order >= 2 | |
491 | */ | |
9a982250 KS |
492 | |
493 | INIT_LIST_HEAD(page_deferred_list(page)); | |
494 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
495 | } | |
496 | ||
ae6f3674 KS |
497 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
498 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
499 | loff_t off, unsigned long flags, unsigned long size) |
500 | { | |
74d2fad1 TK |
501 | loff_t off_end = off + len; |
502 | loff_t off_align = round_up(off, size); | |
ae6f3674 | 503 | unsigned long len_pad, ret; |
74d2fad1 TK |
504 | |
505 | if (off_end <= off_align || (off_end - off_align) < size) | |
506 | return 0; | |
507 | ||
508 | len_pad = len + size; | |
509 | if (len_pad < len || (off + len_pad) < off) | |
510 | return 0; | |
511 | ||
ae6f3674 | 512 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 513 | off >> PAGE_SHIFT, flags); |
ae6f3674 KS |
514 | |
515 | /* | |
516 | * The failure might be due to length padding. The caller will retry | |
517 | * without the padding. | |
518 | */ | |
519 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
520 | return 0; |
521 | ||
ae6f3674 KS |
522 | /* |
523 | * Do not try to align to THP boundary if allocation at the address | |
524 | * hint succeeds. | |
525 | */ | |
526 | if (ret == addr) | |
527 | return addr; | |
528 | ||
529 | ret += (off - ret) & (size - 1); | |
530 | return ret; | |
74d2fad1 TK |
531 | } |
532 | ||
533 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
534 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
535 | { | |
ae6f3674 | 536 | unsigned long ret; |
74d2fad1 TK |
537 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
538 | ||
74d2fad1 TK |
539 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) |
540 | goto out; | |
541 | ||
ae6f3674 KS |
542 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
543 | if (ret) | |
544 | return ret; | |
545 | out: | |
74d2fad1 TK |
546 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
547 | } | |
548 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
549 | ||
82b0f8c3 | 550 | static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, |
bae473a4 | 551 | gfp_t gfp) |
71e3aac0 | 552 | { |
82b0f8c3 | 553 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 554 | struct mem_cgroup *memcg; |
71e3aac0 | 555 | pgtable_t pgtable; |
82b0f8c3 | 556 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
6b31d595 | 557 | int ret = 0; |
71e3aac0 | 558 | |
309381fe | 559 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 560 | |
49f4a8c5 DR |
561 | if (mem_cgroup_try_charge(page, vma->vm_mm, gfp | __GFP_NORETRY, &memcg, |
562 | true)) { | |
6b251fc9 AA |
563 | put_page(page); |
564 | count_vm_event(THP_FAULT_FALLBACK); | |
565 | return VM_FAULT_FALLBACK; | |
566 | } | |
00501b53 | 567 | |
bae473a4 | 568 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
00501b53 | 569 | if (unlikely(!pgtable)) { |
6b31d595 MH |
570 | ret = VM_FAULT_OOM; |
571 | goto release; | |
00501b53 | 572 | } |
71e3aac0 | 573 | |
c79b57e4 | 574 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
575 | /* |
576 | * The memory barrier inside __SetPageUptodate makes sure that | |
577 | * clear_huge_page writes become visible before the set_pmd_at() | |
578 | * write. | |
579 | */ | |
71e3aac0 AA |
580 | __SetPageUptodate(page); |
581 | ||
82b0f8c3 JK |
582 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
583 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 584 | goto unlock_release; |
71e3aac0 AA |
585 | } else { |
586 | pmd_t entry; | |
6b251fc9 | 587 | |
6b31d595 MH |
588 | ret = check_stable_address_space(vma->vm_mm); |
589 | if (ret) | |
590 | goto unlock_release; | |
591 | ||
6b251fc9 AA |
592 | /* Deliver the page fault to userland */ |
593 | if (userfaultfd_missing(vma)) { | |
594 | int ret; | |
595 | ||
82b0f8c3 | 596 | spin_unlock(vmf->ptl); |
f627c2f5 | 597 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 598 | put_page(page); |
bae473a4 | 599 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 600 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
601 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
602 | return ret; | |
603 | } | |
604 | ||
3122359a KS |
605 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
606 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
d281ee61 | 607 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 608 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 609 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
610 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
611 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 KS |
612 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
613 | atomic_long_inc(&vma->vm_mm->nr_ptes); | |
82b0f8c3 | 614 | spin_unlock(vmf->ptl); |
6b251fc9 | 615 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 AA |
616 | } |
617 | ||
aa2e878e | 618 | return 0; |
6b31d595 MH |
619 | unlock_release: |
620 | spin_unlock(vmf->ptl); | |
621 | release: | |
622 | if (pgtable) | |
623 | pte_free(vma->vm_mm, pgtable); | |
624 | mem_cgroup_cancel_charge(page, memcg, true); | |
625 | put_page(page); | |
626 | return ret; | |
627 | ||
71e3aac0 AA |
628 | } |
629 | ||
444eb2a4 | 630 | /* |
21440d7e DR |
631 | * always: directly stall for all thp allocations |
632 | * defer: wake kswapd and fail if not immediately available | |
633 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
634 | * fail if not immediately available | |
635 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
636 | * available | |
637 | * never: never stall for any thp allocation | |
444eb2a4 MG |
638 | */ |
639 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) | |
640 | { | |
21440d7e | 641 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 642 | |
21440d7e | 643 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
25160354 | 644 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
21440d7e DR |
645 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
646 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; | |
647 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
648 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
649 | __GFP_KSWAPD_RECLAIM); | |
650 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
651 | return GFP_TRANSHUGE_LIGHT | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
652 | 0); | |
25160354 | 653 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
654 | } |
655 | ||
c4088ebd | 656 | /* Caller must hold page table lock. */ |
d295e341 | 657 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 658 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 659 | struct page *zero_page) |
fc9fe822 KS |
660 | { |
661 | pmd_t entry; | |
7c414164 AM |
662 | if (!pmd_none(*pmd)) |
663 | return false; | |
5918d10a | 664 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 665 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
666 | if (pgtable) |
667 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 668 | set_pmd_at(mm, haddr, pmd, entry); |
e1f56c89 | 669 | atomic_long_inc(&mm->nr_ptes); |
7c414164 | 670 | return true; |
fc9fe822 KS |
671 | } |
672 | ||
82b0f8c3 | 673 | int do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 674 | { |
82b0f8c3 | 675 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 676 | gfp_t gfp; |
71e3aac0 | 677 | struct page *page; |
82b0f8c3 | 678 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 679 | |
128ec037 | 680 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 681 | return VM_FAULT_FALLBACK; |
128ec037 KS |
682 | if (unlikely(anon_vma_prepare(vma))) |
683 | return VM_FAULT_OOM; | |
6d50e60c | 684 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 685 | return VM_FAULT_OOM; |
82b0f8c3 | 686 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 687 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
688 | transparent_hugepage_use_zero_page()) { |
689 | pgtable_t pgtable; | |
690 | struct page *zero_page; | |
691 | bool set; | |
6b251fc9 | 692 | int ret; |
bae473a4 | 693 | pgtable = pte_alloc_one(vma->vm_mm, haddr); |
128ec037 | 694 | if (unlikely(!pgtable)) |
ba76149f | 695 | return VM_FAULT_OOM; |
6fcb52a5 | 696 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 697 | if (unlikely(!zero_page)) { |
bae473a4 | 698 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 699 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 700 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 701 | } |
82b0f8c3 | 702 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
703 | ret = 0; |
704 | set = false; | |
82b0f8c3 | 705 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
706 | ret = check_stable_address_space(vma->vm_mm); |
707 | if (ret) { | |
708 | spin_unlock(vmf->ptl); | |
709 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
710 | spin_unlock(vmf->ptl); |
711 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
712 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
713 | } else { | |
bae473a4 | 714 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
715 | haddr, vmf->pmd, zero_page); |
716 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
717 | set = true; |
718 | } | |
719 | } else | |
82b0f8c3 | 720 | spin_unlock(vmf->ptl); |
6fcb52a5 | 721 | if (!set) |
bae473a4 | 722 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 723 | return ret; |
71e3aac0 | 724 | } |
444eb2a4 | 725 | gfp = alloc_hugepage_direct_gfpmask(vma); |
077fcf11 | 726 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
727 | if (unlikely(!page)) { |
728 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 729 | return VM_FAULT_FALLBACK; |
128ec037 | 730 | } |
9a982250 | 731 | prep_transhuge_page(page); |
82b0f8c3 | 732 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
733 | } |
734 | ||
ae18d6dc | 735 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
736 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
737 | pgtable_t pgtable) | |
5cad465d MW |
738 | { |
739 | struct mm_struct *mm = vma->vm_mm; | |
740 | pmd_t entry; | |
741 | spinlock_t *ptl; | |
742 | ||
743 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
744 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
745 | if (pfn_t_devmap(pfn)) | |
746 | entry = pmd_mkdevmap(entry); | |
01871e59 RZ |
747 | if (write) { |
748 | entry = pmd_mkyoung(pmd_mkdirty(entry)); | |
749 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 750 | } |
3b6521f5 OH |
751 | |
752 | if (pgtable) { | |
753 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
754 | atomic_long_inc(&mm->nr_ptes); | |
755 | } | |
756 | ||
01871e59 RZ |
757 | set_pmd_at(mm, addr, pmd, entry); |
758 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 759 | spin_unlock(ptl); |
5cad465d MW |
760 | } |
761 | ||
762 | int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, | |
f25748e3 | 763 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
764 | { |
765 | pgprot_t pgprot = vma->vm_page_prot; | |
3b6521f5 | 766 | pgtable_t pgtable = NULL; |
5cad465d MW |
767 | /* |
768 | * If we had pmd_special, we could avoid all these restrictions, | |
769 | * but we need to be consistent with PTEs and architectures that | |
770 | * can't support a 'special' bit. | |
771 | */ | |
772 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
773 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
774 | (VM_PFNMAP|VM_MIXEDMAP)); | |
775 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
f25748e3 | 776 | BUG_ON(!pfn_t_devmap(pfn)); |
5cad465d MW |
777 | |
778 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
779 | return VM_FAULT_SIGBUS; | |
308a047c | 780 | |
3b6521f5 OH |
781 | if (arch_needs_pgtable_deposit()) { |
782 | pgtable = pte_alloc_one(vma->vm_mm, addr); | |
783 | if (!pgtable) | |
784 | return VM_FAULT_OOM; | |
785 | } | |
786 | ||
308a047c BP |
787 | track_pfn_insert(vma, &pgprot, pfn); |
788 | ||
3b6521f5 | 789 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 790 | return VM_FAULT_NOPAGE; |
5cad465d | 791 | } |
dee41079 | 792 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 793 | |
a00cc7d9 MW |
794 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
795 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) | |
796 | { | |
797 | if (likely(vma->vm_flags & VM_WRITE)) | |
798 | pud = pud_mkwrite(pud); | |
799 | return pud; | |
800 | } | |
801 | ||
802 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
803 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
804 | { | |
805 | struct mm_struct *mm = vma->vm_mm; | |
806 | pud_t entry; | |
807 | spinlock_t *ptl; | |
808 | ||
809 | ptl = pud_lock(mm, pud); | |
810 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); | |
811 | if (pfn_t_devmap(pfn)) | |
812 | entry = pud_mkdevmap(entry); | |
813 | if (write) { | |
814 | entry = pud_mkyoung(pud_mkdirty(entry)); | |
815 | entry = maybe_pud_mkwrite(entry, vma); | |
816 | } | |
817 | set_pud_at(mm, addr, pud, entry); | |
818 | update_mmu_cache_pud(vma, addr, pud); | |
819 | spin_unlock(ptl); | |
820 | } | |
821 | ||
822 | int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
823 | pud_t *pud, pfn_t pfn, bool write) | |
824 | { | |
825 | pgprot_t pgprot = vma->vm_page_prot; | |
826 | /* | |
827 | * If we had pud_special, we could avoid all these restrictions, | |
828 | * but we need to be consistent with PTEs and architectures that | |
829 | * can't support a 'special' bit. | |
830 | */ | |
831 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); | |
832 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
833 | (VM_PFNMAP|VM_MIXEDMAP)); | |
834 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
835 | BUG_ON(!pfn_t_devmap(pfn)); | |
836 | ||
837 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
838 | return VM_FAULT_SIGBUS; | |
839 | ||
840 | track_pfn_insert(vma, &pgprot, pfn); | |
841 | ||
842 | insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); | |
843 | return VM_FAULT_NOPAGE; | |
844 | } | |
845 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
846 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
847 | ||
3565fce3 | 848 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
01ca9727 | 849 | pmd_t *pmd, int flags) |
3565fce3 DW |
850 | { |
851 | pmd_t _pmd; | |
852 | ||
01ca9727 KS |
853 | _pmd = pmd_mkyoung(*pmd); |
854 | if (flags & FOLL_WRITE) | |
855 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 856 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
01ca9727 | 857 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
858 | update_mmu_cache_pmd(vma, addr, pmd); |
859 | } | |
860 | ||
861 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
862 | pmd_t *pmd, int flags) | |
863 | { | |
864 | unsigned long pfn = pmd_pfn(*pmd); | |
865 | struct mm_struct *mm = vma->vm_mm; | |
866 | struct dev_pagemap *pgmap; | |
867 | struct page *page; | |
868 | ||
869 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
870 | ||
8310d48b KF |
871 | /* |
872 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
873 | * not be in this function with `flags & FOLL_COW` set. | |
874 | */ | |
875 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
876 | ||
3565fce3 DW |
877 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
878 | return NULL; | |
879 | ||
880 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
881 | /* pass */; | |
882 | else | |
883 | return NULL; | |
884 | ||
885 | if (flags & FOLL_TOUCH) | |
01ca9727 | 886 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
887 | |
888 | /* | |
889 | * device mapped pages can only be returned if the | |
890 | * caller will manage the page reference count. | |
891 | */ | |
892 | if (!(flags & FOLL_GET)) | |
893 | return ERR_PTR(-EEXIST); | |
894 | ||
895 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
896 | pgmap = get_dev_pagemap(pfn, NULL); | |
897 | if (!pgmap) | |
898 | return ERR_PTR(-EFAULT); | |
899 | page = pfn_to_page(pfn); | |
900 | get_page(page); | |
901 | put_dev_pagemap(pgmap); | |
902 | ||
903 | return page; | |
904 | } | |
905 | ||
71e3aac0 AA |
906 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
907 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
908 | struct vm_area_struct *vma) | |
909 | { | |
c4088ebd | 910 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
911 | struct page *src_page; |
912 | pmd_t pmd; | |
12c9d70b | 913 | pgtable_t pgtable = NULL; |
628d47ce | 914 | int ret = -ENOMEM; |
71e3aac0 | 915 | |
628d47ce KS |
916 | /* Skip if can be re-fill on fault */ |
917 | if (!vma_is_anonymous(vma)) | |
918 | return 0; | |
919 | ||
920 | pgtable = pte_alloc_one(dst_mm, addr); | |
921 | if (unlikely(!pgtable)) | |
922 | goto out; | |
71e3aac0 | 923 | |
c4088ebd KS |
924 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
925 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
926 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
927 | |
928 | ret = -EAGAIN; | |
929 | pmd = *src_pmd; | |
84c3fc4e ZY |
930 | |
931 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
932 | if (unlikely(is_swap_pmd(pmd))) { | |
933 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
934 | ||
935 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
936 | if (is_write_migration_entry(entry)) { | |
937 | make_migration_entry_read(&entry); | |
938 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
939 | if (pmd_swp_soft_dirty(*src_pmd)) |
940 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
941 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
942 | } | |
dd8a67f9 ZY |
943 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
944 | atomic_long_inc(&dst_mm->nr_ptes); | |
945 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); | |
84c3fc4e ZY |
946 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
947 | ret = 0; | |
948 | goto out_unlock; | |
949 | } | |
950 | #endif | |
951 | ||
628d47ce | 952 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
953 | pte_free(dst_mm, pgtable); |
954 | goto out_unlock; | |
955 | } | |
fc9fe822 | 956 | /* |
c4088ebd | 957 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
958 | * under splitting since we don't split the page itself, only pmd to |
959 | * a page table. | |
960 | */ | |
961 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 962 | struct page *zero_page; |
97ae1749 KS |
963 | /* |
964 | * get_huge_zero_page() will never allocate a new page here, | |
965 | * since we already have a zero page to copy. It just takes a | |
966 | * reference. | |
967 | */ | |
6fcb52a5 | 968 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 969 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 970 | zero_page); |
fc9fe822 KS |
971 | ret = 0; |
972 | goto out_unlock; | |
973 | } | |
de466bd6 | 974 | |
628d47ce KS |
975 | src_page = pmd_page(pmd); |
976 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
977 | get_page(src_page); | |
978 | page_dup_rmap(src_page, true); | |
979 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
980 | atomic_long_inc(&dst_mm->nr_ptes); | |
981 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); | |
71e3aac0 AA |
982 | |
983 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
984 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
985 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
986 | |
987 | ret = 0; | |
988 | out_unlock: | |
c4088ebd KS |
989 | spin_unlock(src_ptl); |
990 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
991 | out: |
992 | return ret; | |
993 | } | |
994 | ||
a00cc7d9 MW |
995 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
996 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
01ca9727 | 997 | pud_t *pud, int flags) |
a00cc7d9 MW |
998 | { |
999 | pud_t _pud; | |
1000 | ||
01ca9727 KS |
1001 | _pud = pud_mkyoung(*pud); |
1002 | if (flags & FOLL_WRITE) | |
1003 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1004 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
01ca9727 | 1005 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1006 | update_mmu_cache_pud(vma, addr, pud); |
1007 | } | |
1008 | ||
1009 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
1010 | pud_t *pud, int flags) | |
1011 | { | |
1012 | unsigned long pfn = pud_pfn(*pud); | |
1013 | struct mm_struct *mm = vma->vm_mm; | |
1014 | struct dev_pagemap *pgmap; | |
1015 | struct page *page; | |
1016 | ||
1017 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1018 | ||
1019 | if (flags & FOLL_WRITE && !pud_write(*pud)) | |
1020 | return NULL; | |
1021 | ||
1022 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1023 | /* pass */; | |
1024 | else | |
1025 | return NULL; | |
1026 | ||
1027 | if (flags & FOLL_TOUCH) | |
01ca9727 | 1028 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1029 | |
1030 | /* | |
1031 | * device mapped pages can only be returned if the | |
1032 | * caller will manage the page reference count. | |
1033 | */ | |
1034 | if (!(flags & FOLL_GET)) | |
1035 | return ERR_PTR(-EEXIST); | |
1036 | ||
1037 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
1038 | pgmap = get_dev_pagemap(pfn, NULL); | |
1039 | if (!pgmap) | |
1040 | return ERR_PTR(-EFAULT); | |
1041 | page = pfn_to_page(pfn); | |
1042 | get_page(page); | |
1043 | put_dev_pagemap(pgmap); | |
1044 | ||
1045 | return page; | |
1046 | } | |
1047 | ||
1048 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1049 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1050 | struct vm_area_struct *vma) | |
1051 | { | |
1052 | spinlock_t *dst_ptl, *src_ptl; | |
1053 | pud_t pud; | |
1054 | int ret; | |
1055 | ||
1056 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1057 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1058 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1059 | ||
1060 | ret = -EAGAIN; | |
1061 | pud = *src_pud; | |
1062 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1063 | goto out_unlock; | |
1064 | ||
1065 | /* | |
1066 | * When page table lock is held, the huge zero pud should not be | |
1067 | * under splitting since we don't split the page itself, only pud to | |
1068 | * a page table. | |
1069 | */ | |
1070 | if (is_huge_zero_pud(pud)) { | |
1071 | /* No huge zero pud yet */ | |
1072 | } | |
1073 | ||
1074 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1075 | pud = pud_mkold(pud_wrprotect(pud)); | |
1076 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1077 | ||
1078 | ret = 0; | |
1079 | out_unlock: | |
1080 | spin_unlock(src_ptl); | |
1081 | spin_unlock(dst_ptl); | |
1082 | return ret; | |
1083 | } | |
1084 | ||
1085 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1086 | { | |
1087 | pud_t entry; | |
1088 | unsigned long haddr; | |
1089 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1090 | ||
1091 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1092 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1093 | goto unlock; | |
1094 | ||
1095 | entry = pud_mkyoung(orig_pud); | |
1096 | if (write) | |
1097 | entry = pud_mkdirty(entry); | |
1098 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1099 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1100 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1101 | ||
1102 | unlock: | |
1103 | spin_unlock(vmf->ptl); | |
1104 | } | |
1105 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1106 | ||
82b0f8c3 | 1107 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1108 | { |
1109 | pmd_t entry; | |
1110 | unsigned long haddr; | |
20f664aa | 1111 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1112 | |
82b0f8c3 JK |
1113 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1114 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1115 | goto unlock; |
1116 | ||
1117 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1118 | if (write) |
1119 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1120 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1121 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1122 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1123 | |
1124 | unlock: | |
82b0f8c3 | 1125 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1126 | } |
1127 | ||
82b0f8c3 | 1128 | static int do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, pmd_t orig_pmd, |
bae473a4 | 1129 | struct page *page) |
71e3aac0 | 1130 | { |
82b0f8c3 JK |
1131 | struct vm_area_struct *vma = vmf->vma; |
1132 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1133 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1134 | pgtable_t pgtable; |
1135 | pmd_t _pmd; | |
1136 | int ret = 0, i; | |
1137 | struct page **pages; | |
2ec74c3e SG |
1138 | unsigned long mmun_start; /* For mmu_notifiers */ |
1139 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1140 | |
1141 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1142 | GFP_KERNEL); | |
1143 | if (unlikely(!pages)) { | |
1144 | ret |= VM_FAULT_OOM; | |
1145 | goto out; | |
1146 | } | |
1147 | ||
1148 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1149 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1150 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1151 | if (unlikely(!pages[i] || |
bae473a4 KS |
1152 | mem_cgroup_try_charge(pages[i], vma->vm_mm, |
1153 | GFP_KERNEL, &memcg, false))) { | |
b9bbfbe3 | 1154 | if (pages[i]) |
71e3aac0 | 1155 | put_page(pages[i]); |
b9bbfbe3 | 1156 | while (--i >= 0) { |
00501b53 JW |
1157 | memcg = (void *)page_private(pages[i]); |
1158 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1159 | mem_cgroup_cancel_charge(pages[i], memcg, |
1160 | false); | |
b9bbfbe3 AA |
1161 | put_page(pages[i]); |
1162 | } | |
71e3aac0 AA |
1163 | kfree(pages); |
1164 | ret |= VM_FAULT_OOM; | |
1165 | goto out; | |
1166 | } | |
00501b53 | 1167 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1168 | } |
1169 | ||
1170 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1171 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1172 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1173 | __SetPageUptodate(pages[i]); |
1174 | cond_resched(); | |
1175 | } | |
1176 | ||
2ec74c3e SG |
1177 | mmun_start = haddr; |
1178 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1179 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1180 | |
82b0f8c3 JK |
1181 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1182 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1183 | goto out_free_pages; |
309381fe | 1184 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1185 | |
82b0f8c3 | 1186 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 AA |
1187 | /* leave pmd empty until pte is filled */ |
1188 | ||
82b0f8c3 | 1189 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1190 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1191 | |
1192 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1193 | pte_t entry; |
71e3aac0 AA |
1194 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1195 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1196 | memcg = (void *)page_private(pages[i]); |
1197 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1198 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1199 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1200 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1201 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1202 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1203 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1204 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1205 | } |
1206 | kfree(pages); | |
1207 | ||
71e3aac0 | 1208 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1209 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1210 | page_remove_rmap(page, true); |
82b0f8c3 | 1211 | spin_unlock(vmf->ptl); |
71e3aac0 | 1212 | |
bae473a4 | 1213 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1214 | |
71e3aac0 AA |
1215 | ret |= VM_FAULT_WRITE; |
1216 | put_page(page); | |
1217 | ||
1218 | out: | |
1219 | return ret; | |
1220 | ||
1221 | out_free_pages: | |
82b0f8c3 | 1222 | spin_unlock(vmf->ptl); |
bae473a4 | 1223 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
b9bbfbe3 | 1224 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1225 | memcg = (void *)page_private(pages[i]); |
1226 | set_page_private(pages[i], 0); | |
f627c2f5 | 1227 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1228 | put_page(pages[i]); |
b9bbfbe3 | 1229 | } |
71e3aac0 AA |
1230 | kfree(pages); |
1231 | goto out; | |
1232 | } | |
1233 | ||
82b0f8c3 | 1234 | int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1235 | { |
82b0f8c3 | 1236 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1237 | struct page *page = NULL, *new_page; |
00501b53 | 1238 | struct mem_cgroup *memcg; |
82b0f8c3 | 1239 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2ec74c3e SG |
1240 | unsigned long mmun_start; /* For mmu_notifiers */ |
1241 | unsigned long mmun_end; /* For mmu_notifiers */ | |
3b363692 | 1242 | gfp_t huge_gfp; /* for allocation and charge */ |
bae473a4 | 1243 | int ret = 0; |
71e3aac0 | 1244 | |
82b0f8c3 | 1245 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1246 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1247 | if (is_huge_zero_pmd(orig_pmd)) |
1248 | goto alloc; | |
82b0f8c3 JK |
1249 | spin_lock(vmf->ptl); |
1250 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1251 | goto out_unlock; |
1252 | ||
1253 | page = pmd_page(orig_pmd); | |
309381fe | 1254 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1255 | /* |
1256 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1257 | * part. |
1f25fe20 | 1258 | */ |
ba3c4ce6 HY |
1259 | if (!trylock_page(page)) { |
1260 | get_page(page); | |
1261 | spin_unlock(vmf->ptl); | |
1262 | lock_page(page); | |
1263 | spin_lock(vmf->ptl); | |
1264 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1265 | unlock_page(page); | |
1266 | put_page(page); | |
1267 | goto out_unlock; | |
1268 | } | |
1269 | put_page(page); | |
1270 | } | |
1271 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1272 | pmd_t entry; |
1273 | entry = pmd_mkyoung(orig_pmd); | |
1274 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
82b0f8c3 JK |
1275 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1276 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1277 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1278 | unlock_page(page); |
71e3aac0 AA |
1279 | goto out_unlock; |
1280 | } | |
ba3c4ce6 | 1281 | unlock_page(page); |
ddc58f27 | 1282 | get_page(page); |
82b0f8c3 | 1283 | spin_unlock(vmf->ptl); |
93b4796d | 1284 | alloc: |
71e3aac0 | 1285 | if (transparent_hugepage_enabled(vma) && |
077fcf11 | 1286 | !transparent_hugepage_debug_cow()) { |
444eb2a4 | 1287 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
3b363692 | 1288 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); |
077fcf11 | 1289 | } else |
71e3aac0 AA |
1290 | new_page = NULL; |
1291 | ||
9a982250 KS |
1292 | if (likely(new_page)) { |
1293 | prep_transhuge_page(new_page); | |
1294 | } else { | |
eecc1e42 | 1295 | if (!page) { |
82b0f8c3 | 1296 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1297 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1298 | } else { |
82b0f8c3 | 1299 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1300 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1301 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1302 | ret |= VM_FAULT_FALLBACK; |
1303 | } | |
ddc58f27 | 1304 | put_page(page); |
93b4796d | 1305 | } |
17766dde | 1306 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1307 | goto out; |
1308 | } | |
1309 | ||
bae473a4 | 1310 | if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm, |
49f4a8c5 | 1311 | huge_gfp | __GFP_NORETRY, &memcg, true))) { |
b9bbfbe3 | 1312 | put_page(new_page); |
82b0f8c3 | 1313 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1314 | if (page) |
ddc58f27 | 1315 | put_page(page); |
9845cbbd | 1316 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1317 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1318 | goto out; |
1319 | } | |
1320 | ||
17766dde DR |
1321 | count_vm_event(THP_FAULT_ALLOC); |
1322 | ||
eecc1e42 | 1323 | if (!page) |
c79b57e4 | 1324 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d KS |
1325 | else |
1326 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1327 | __SetPageUptodate(new_page); |
1328 | ||
2ec74c3e SG |
1329 | mmun_start = haddr; |
1330 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
bae473a4 | 1331 | mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end); |
2ec74c3e | 1332 | |
82b0f8c3 | 1333 | spin_lock(vmf->ptl); |
93b4796d | 1334 | if (page) |
ddc58f27 | 1335 | put_page(page); |
82b0f8c3 JK |
1336 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1337 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1338 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1339 | put_page(new_page); |
2ec74c3e | 1340 | goto out_mn; |
b9bbfbe3 | 1341 | } else { |
71e3aac0 | 1342 | pmd_t entry; |
3122359a KS |
1343 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1344 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
82b0f8c3 | 1345 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1346 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1347 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1348 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1349 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1350 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1351 | if (!page) { |
bae473a4 | 1352 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1353 | } else { |
309381fe | 1354 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1355 | page_remove_rmap(page, true); |
93b4796d KS |
1356 | put_page(page); |
1357 | } | |
71e3aac0 AA |
1358 | ret |= VM_FAULT_WRITE; |
1359 | } | |
82b0f8c3 | 1360 | spin_unlock(vmf->ptl); |
2ec74c3e | 1361 | out_mn: |
bae473a4 | 1362 | mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end); |
71e3aac0 AA |
1363 | out: |
1364 | return ret; | |
2ec74c3e | 1365 | out_unlock: |
82b0f8c3 | 1366 | spin_unlock(vmf->ptl); |
2ec74c3e | 1367 | return ret; |
71e3aac0 AA |
1368 | } |
1369 | ||
8310d48b KF |
1370 | /* |
1371 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1372 | * after we've gone through a COW cycle and they are dirty. | |
1373 | */ | |
1374 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1375 | { | |
1376 | return pmd_write(pmd) || | |
1377 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
1378 | } | |
1379 | ||
b676b293 | 1380 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1381 | unsigned long addr, |
1382 | pmd_t *pmd, | |
1383 | unsigned int flags) | |
1384 | { | |
b676b293 | 1385 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1386 | struct page *page = NULL; |
1387 | ||
c4088ebd | 1388 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1389 | |
8310d48b | 1390 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1391 | goto out; |
1392 | ||
85facf25 KS |
1393 | /* Avoid dumping huge zero page */ |
1394 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1395 | return ERR_PTR(-EFAULT); | |
1396 | ||
2b4847e7 | 1397 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1398 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1399 | goto out; |
1400 | ||
71e3aac0 | 1401 | page = pmd_page(*pmd); |
ca120cf6 | 1402 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1403 | if (flags & FOLL_TOUCH) |
01ca9727 | 1404 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1405 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1406 | /* |
1407 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1408 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1409 | * | |
9a73f61b KS |
1410 | * For anon THP: |
1411 | * | |
e90309c9 KS |
1412 | * In most cases the pmd is the only mapping of the page as we |
1413 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1414 | * writable private mappings in populate_vma_page_range(). | |
1415 | * | |
1416 | * The only scenario when we have the page shared here is if we | |
1417 | * mlocking read-only mapping shared over fork(). We skip | |
1418 | * mlocking such pages. | |
9a73f61b KS |
1419 | * |
1420 | * For file THP: | |
1421 | * | |
1422 | * We can expect PageDoubleMap() to be stable under page lock: | |
1423 | * for file pages we set it in page_add_file_rmap(), which | |
1424 | * requires page to be locked. | |
e90309c9 | 1425 | */ |
9a73f61b KS |
1426 | |
1427 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1428 | goto skip_mlock; | |
1429 | if (PageDoubleMap(page) || !page->mapping) | |
1430 | goto skip_mlock; | |
1431 | if (!trylock_page(page)) | |
1432 | goto skip_mlock; | |
1433 | lru_add_drain(); | |
1434 | if (page->mapping && !PageDoubleMap(page)) | |
1435 | mlock_vma_page(page); | |
1436 | unlock_page(page); | |
b676b293 | 1437 | } |
9a73f61b | 1438 | skip_mlock: |
71e3aac0 | 1439 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1440 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1441 | if (flags & FOLL_GET) |
ddc58f27 | 1442 | get_page(page); |
71e3aac0 AA |
1443 | |
1444 | out: | |
1445 | return page; | |
1446 | } | |
1447 | ||
d10e63f2 | 1448 | /* NUMA hinting page fault entry point for trans huge pmds */ |
82b0f8c3 | 1449 | int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1450 | { |
82b0f8c3 | 1451 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1452 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1453 | struct page *page; |
82b0f8c3 | 1454 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
8191acbd | 1455 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1456 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1457 | bool page_locked; |
1458 | bool migrated = false; | |
b191f9b1 | 1459 | bool was_writable; |
6688cc05 | 1460 | int flags = 0; |
d10e63f2 | 1461 | |
82b0f8c3 JK |
1462 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1463 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1464 | goto out_unlock; |
1465 | ||
de466bd6 MG |
1466 | /* |
1467 | * If there are potential migrations, wait for completion and retry | |
1468 | * without disrupting NUMA hinting information. Do not relock and | |
1469 | * check_same as the page may no longer be mapped. | |
1470 | */ | |
82b0f8c3 JK |
1471 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1472 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1473 | if (!get_page_unless_zero(page)) |
1474 | goto out_unlock; | |
82b0f8c3 | 1475 | spin_unlock(vmf->ptl); |
5d833062 | 1476 | wait_on_page_locked(page); |
3c226c63 | 1477 | put_page(page); |
de466bd6 MG |
1478 | goto out; |
1479 | } | |
1480 | ||
d10e63f2 | 1481 | page = pmd_page(pmd); |
a1a46184 | 1482 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1483 | page_nid = page_to_nid(page); |
90572890 | 1484 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1485 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1486 | if (page_nid == this_nid) { |
03c5a6e1 | 1487 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1488 | flags |= TNF_FAULT_LOCAL; |
1489 | } | |
4daae3b4 | 1490 | |
bea66fbd | 1491 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1492 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1493 | flags |= TNF_NO_GROUP; |
1494 | ||
ff9042b1 MG |
1495 | /* |
1496 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1497 | * page_table_lock if at all possible | |
1498 | */ | |
b8916634 MG |
1499 | page_locked = trylock_page(page); |
1500 | target_nid = mpol_misplaced(page, vma, haddr); | |
1501 | if (target_nid == -1) { | |
1502 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1503 | if (page_locked) |
b8916634 | 1504 | goto clear_pmdnuma; |
2b4847e7 | 1505 | } |
4daae3b4 | 1506 | |
de466bd6 | 1507 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1508 | if (!page_locked) { |
3c226c63 MR |
1509 | page_nid = -1; |
1510 | if (!get_page_unless_zero(page)) | |
1511 | goto out_unlock; | |
82b0f8c3 | 1512 | spin_unlock(vmf->ptl); |
b8916634 | 1513 | wait_on_page_locked(page); |
3c226c63 | 1514 | put_page(page); |
b8916634 MG |
1515 | goto out; |
1516 | } | |
1517 | ||
2b4847e7 MG |
1518 | /* |
1519 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1520 | * to serialises splits | |
1521 | */ | |
b8916634 | 1522 | get_page(page); |
82b0f8c3 | 1523 | spin_unlock(vmf->ptl); |
b8916634 | 1524 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1525 | |
c69307d5 | 1526 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1527 | spin_lock(vmf->ptl); |
1528 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1529 | unlock_page(page); |
1530 | put_page(page); | |
a54a407f | 1531 | page_nid = -1; |
4daae3b4 | 1532 | goto out_unlock; |
b32967ff | 1533 | } |
ff9042b1 | 1534 | |
c3a489ca MG |
1535 | /* Bail if we fail to protect against THP splits for any reason */ |
1536 | if (unlikely(!anon_vma)) { | |
1537 | put_page(page); | |
1538 | page_nid = -1; | |
1539 | goto clear_pmdnuma; | |
1540 | } | |
1541 | ||
8b1b436d PZ |
1542 | /* |
1543 | * Since we took the NUMA fault, we must have observed the !accessible | |
1544 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1545 | * modifying the page we're about to migrate. | |
1546 | * | |
1547 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1548 | * inc_tlb_flush_pending(). |
1549 | * | |
1550 | * We are not sure a pending tlb flush here is for a huge page | |
1551 | * mapping or not. Hence use the tlb range variant | |
8b1b436d PZ |
1552 | */ |
1553 | if (mm_tlb_flush_pending(vma->vm_mm)) | |
ccde85ba | 1554 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
8b1b436d | 1555 | |
a54a407f MG |
1556 | /* |
1557 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1558 | * and access rights restored. |
a54a407f | 1559 | */ |
82b0f8c3 | 1560 | spin_unlock(vmf->ptl); |
8b1b436d | 1561 | |
bae473a4 | 1562 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1563 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1564 | if (migrated) { |
1565 | flags |= TNF_MIGRATED; | |
8191acbd | 1566 | page_nid = target_nid; |
074c2381 MG |
1567 | } else |
1568 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1569 | |
8191acbd | 1570 | goto out; |
b32967ff | 1571 | clear_pmdnuma: |
a54a407f | 1572 | BUG_ON(!PageLocked(page)); |
288bc549 | 1573 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1574 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1575 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1576 | if (was_writable) |
1577 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1578 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1579 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1580 | unlock_page(page); |
d10e63f2 | 1581 | out_unlock: |
82b0f8c3 | 1582 | spin_unlock(vmf->ptl); |
b8916634 MG |
1583 | |
1584 | out: | |
1585 | if (anon_vma) | |
1586 | page_unlock_anon_vma_read(anon_vma); | |
1587 | ||
8191acbd | 1588 | if (page_nid != -1) |
82b0f8c3 | 1589 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1590 | flags); |
8191acbd | 1591 | |
d10e63f2 MG |
1592 | return 0; |
1593 | } | |
1594 | ||
319904ad HY |
1595 | /* |
1596 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1597 | * Otherwise, return false. | |
1598 | */ | |
1599 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1600 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1601 | { |
1602 | spinlock_t *ptl; | |
1603 | pmd_t orig_pmd; | |
1604 | struct page *page; | |
1605 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1606 | bool ret = false; |
b8d3c4c3 | 1607 | |
07e32661 AK |
1608 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1609 | ||
b6ec57f4 KS |
1610 | ptl = pmd_trans_huge_lock(pmd, vma); |
1611 | if (!ptl) | |
25eedabe | 1612 | goto out_unlocked; |
b8d3c4c3 MK |
1613 | |
1614 | orig_pmd = *pmd; | |
319904ad | 1615 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1616 | goto out; |
b8d3c4c3 | 1617 | |
84c3fc4e ZY |
1618 | if (unlikely(!pmd_present(orig_pmd))) { |
1619 | VM_BUG_ON(thp_migration_supported() && | |
1620 | !is_pmd_migration_entry(orig_pmd)); | |
1621 | goto out; | |
1622 | } | |
1623 | ||
b8d3c4c3 MK |
1624 | page = pmd_page(orig_pmd); |
1625 | /* | |
1626 | * If other processes are mapping this page, we couldn't discard | |
1627 | * the page unless they all do MADV_FREE so let's skip the page. | |
1628 | */ | |
1629 | if (page_mapcount(page) != 1) | |
1630 | goto out; | |
1631 | ||
1632 | if (!trylock_page(page)) | |
1633 | goto out; | |
1634 | ||
1635 | /* | |
1636 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1637 | * will deactivate only them. | |
1638 | */ | |
1639 | if (next - addr != HPAGE_PMD_SIZE) { | |
1640 | get_page(page); | |
1641 | spin_unlock(ptl); | |
9818b8cd | 1642 | split_huge_page(page); |
b8d3c4c3 | 1643 | unlock_page(page); |
bbf29ffc | 1644 | put_page(page); |
b8d3c4c3 MK |
1645 | goto out_unlocked; |
1646 | } | |
1647 | ||
1648 | if (PageDirty(page)) | |
1649 | ClearPageDirty(page); | |
1650 | unlock_page(page); | |
1651 | ||
b8d3c4c3 | 1652 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1653 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1654 | orig_pmd = pmd_mkold(orig_pmd); |
1655 | orig_pmd = pmd_mkclean(orig_pmd); | |
1656 | ||
1657 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1658 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1659 | } | |
802a3a92 SL |
1660 | |
1661 | mark_page_lazyfree(page); | |
319904ad | 1662 | ret = true; |
b8d3c4c3 MK |
1663 | out: |
1664 | spin_unlock(ptl); | |
1665 | out_unlocked: | |
1666 | return ret; | |
1667 | } | |
1668 | ||
953c66c2 AK |
1669 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1670 | { | |
1671 | pgtable_t pgtable; | |
1672 | ||
1673 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1674 | pte_free(mm, pgtable); | |
1675 | atomic_long_dec(&mm->nr_ptes); | |
1676 | } | |
1677 | ||
71e3aac0 | 1678 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1679 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1680 | { |
da146769 | 1681 | pmd_t orig_pmd; |
bf929152 | 1682 | spinlock_t *ptl; |
71e3aac0 | 1683 | |
07e32661 AK |
1684 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1685 | ||
b6ec57f4 KS |
1686 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1687 | if (!ptl) | |
da146769 KS |
1688 | return 0; |
1689 | /* | |
1690 | * For architectures like ppc64 we look at deposited pgtable | |
1691 | * when calling pmdp_huge_get_and_clear. So do the | |
1692 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1693 | * operations. | |
1694 | */ | |
1695 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1696 | tlb->fullmm); | |
1697 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1698 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1699 | if (arch_needs_pgtable_deposit()) |
1700 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1701 | spin_unlock(ptl); |
1702 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1703 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1704 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1705 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1706 | spin_unlock(ptl); |
c0f2e176 | 1707 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1708 | } else { |
616b8371 ZY |
1709 | struct page *page = NULL; |
1710 | int flush_needed = 1; | |
1711 | ||
1712 | if (pmd_present(orig_pmd)) { | |
1713 | page = pmd_page(orig_pmd); | |
1714 | page_remove_rmap(page, true); | |
1715 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1716 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1717 | } else if (thp_migration_supported()) { | |
1718 | swp_entry_t entry; | |
1719 | ||
1720 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1721 | entry = pmd_to_swp_entry(orig_pmd); | |
1722 | page = pfn_to_page(swp_offset(entry)); | |
1723 | flush_needed = 0; | |
1724 | } else | |
1725 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1726 | ||
b5072380 | 1727 | if (PageAnon(page)) { |
c14a6eb4 | 1728 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1729 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1730 | } else { | |
953c66c2 AK |
1731 | if (arch_needs_pgtable_deposit()) |
1732 | zap_deposited_table(tlb->mm, pmd); | |
b5072380 KS |
1733 | add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR); |
1734 | } | |
616b8371 | 1735 | |
da146769 | 1736 | spin_unlock(ptl); |
616b8371 ZY |
1737 | if (flush_needed) |
1738 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1739 | } |
da146769 | 1740 | return 1; |
71e3aac0 AA |
1741 | } |
1742 | ||
1dd38b6c AK |
1743 | #ifndef pmd_move_must_withdraw |
1744 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1745 | spinlock_t *old_pmd_ptl, | |
1746 | struct vm_area_struct *vma) | |
1747 | { | |
1748 | /* | |
1749 | * With split pmd lock we also need to move preallocated | |
1750 | * PTE page table if new_pmd is on different PMD page table. | |
1751 | * | |
1752 | * We also don't deposit and withdraw tables for file pages. | |
1753 | */ | |
1754 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1755 | } | |
1756 | #endif | |
1757 | ||
ab6e3d09 NH |
1758 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1759 | { | |
1760 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1761 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1762 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1763 | else if (pmd_present(pmd)) | |
1764 | pmd = pmd_mksoft_dirty(pmd); | |
1765 | #endif | |
1766 | return pmd; | |
1767 | } | |
1768 | ||
bf8616d5 | 1769 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1770 | unsigned long new_addr, unsigned long old_end, |
541500ab | 1771 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1772 | { |
bf929152 | 1773 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1774 | pmd_t pmd; |
37a1c49a | 1775 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1776 | bool force_flush = false; |
37a1c49a AA |
1777 | |
1778 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1779 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1780 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1781 | return false; |
37a1c49a AA |
1782 | |
1783 | /* | |
1784 | * The destination pmd shouldn't be established, free_pgtables() | |
1785 | * should have release it. | |
1786 | */ | |
1787 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1788 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1789 | return false; |
37a1c49a AA |
1790 | } |
1791 | ||
bf929152 KS |
1792 | /* |
1793 | * We don't have to worry about the ordering of src and dst | |
1794 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1795 | */ | |
b6ec57f4 KS |
1796 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1797 | if (old_ptl) { | |
bf929152 KS |
1798 | new_ptl = pmd_lockptr(mm, new_pmd); |
1799 | if (new_ptl != old_ptl) | |
1800 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1801 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
541500ab | 1802 | if (pmd_present(pmd)) |
a2ce2666 | 1803 | force_flush = true; |
025c5b24 | 1804 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1805 | |
1dd38b6c | 1806 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1807 | pgtable_t pgtable; |
3592806c KS |
1808 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1809 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1810 | } |
ab6e3d09 NH |
1811 | pmd = move_soft_dirty_pmd(pmd); |
1812 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1813 | if (force_flush) |
1814 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
541500ab LT |
1815 | if (new_ptl != old_ptl) |
1816 | spin_unlock(new_ptl); | |
bf929152 | 1817 | spin_unlock(old_ptl); |
4b471e88 | 1818 | return true; |
37a1c49a | 1819 | } |
4b471e88 | 1820 | return false; |
37a1c49a AA |
1821 | } |
1822 | ||
f123d74a MG |
1823 | /* |
1824 | * Returns | |
1825 | * - 0 if PMD could not be locked | |
1826 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1827 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1828 | */ | |
cd7548ab | 1829 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1830 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1831 | { |
1832 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1833 | spinlock_t *ptl; |
0a85e51d KS |
1834 | pmd_t entry; |
1835 | bool preserve_write; | |
1836 | int ret; | |
cd7548ab | 1837 | |
b6ec57f4 | 1838 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1839 | if (!ptl) |
1840 | return 0; | |
e944fd67 | 1841 | |
0a85e51d KS |
1842 | preserve_write = prot_numa && pmd_write(*pmd); |
1843 | ret = 1; | |
e944fd67 | 1844 | |
84c3fc4e ZY |
1845 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1846 | if (is_swap_pmd(*pmd)) { | |
1847 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1848 | ||
1849 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1850 | if (is_write_migration_entry(entry)) { | |
1851 | pmd_t newpmd; | |
1852 | /* | |
1853 | * A protection check is difficult so | |
1854 | * just be safe and disable write | |
1855 | */ | |
1856 | make_migration_entry_read(&entry); | |
1857 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1858 | if (pmd_swp_soft_dirty(*pmd)) |
1859 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1860 | set_pmd_at(mm, addr, pmd, newpmd); |
1861 | } | |
1862 | goto unlock; | |
1863 | } | |
1864 | #endif | |
1865 | ||
0a85e51d KS |
1866 | /* |
1867 | * Avoid trapping faults against the zero page. The read-only | |
1868 | * data is likely to be read-cached on the local CPU and | |
1869 | * local/remote hits to the zero page are not interesting. | |
1870 | */ | |
1871 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1872 | goto unlock; | |
025c5b24 | 1873 | |
0a85e51d KS |
1874 | if (prot_numa && pmd_protnone(*pmd)) |
1875 | goto unlock; | |
1876 | ||
ced10803 KS |
1877 | /* |
1878 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1879 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1880 | * which is also under down_read(mmap_sem): | |
1881 | * | |
1882 | * CPU0: CPU1: | |
1883 | * change_huge_pmd(prot_numa=1) | |
1884 | * pmdp_huge_get_and_clear_notify() | |
1885 | * madvise_dontneed() | |
1886 | * zap_pmd_range() | |
1887 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1888 | * // skip the pmd | |
1889 | * set_pmd_at(); | |
1890 | * // pmd is re-established | |
1891 | * | |
1892 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1893 | * which may break userspace. | |
1894 | * | |
1895 | * pmdp_invalidate() is required to make sure we don't miss | |
1896 | * dirty/young flags set by hardware. | |
1897 | */ | |
1898 | entry = *pmd; | |
1899 | pmdp_invalidate(vma, addr, pmd); | |
1900 | ||
1901 | /* | |
1902 | * Recover dirty/young flags. It relies on pmdp_invalidate to not | |
1903 | * corrupt them. | |
1904 | */ | |
1905 | if (pmd_dirty(*pmd)) | |
1906 | entry = pmd_mkdirty(entry); | |
1907 | if (pmd_young(*pmd)) | |
1908 | entry = pmd_mkyoung(entry); | |
1909 | ||
0a85e51d KS |
1910 | entry = pmd_modify(entry, newprot); |
1911 | if (preserve_write) | |
1912 | entry = pmd_mk_savedwrite(entry); | |
1913 | ret = HPAGE_PMD_NR; | |
1914 | set_pmd_at(mm, addr, pmd, entry); | |
1915 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1916 | unlock: | |
1917 | spin_unlock(ptl); | |
025c5b24 NH |
1918 | return ret; |
1919 | } | |
1920 | ||
1921 | /* | |
8f19b0c0 | 1922 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1923 | * |
8f19b0c0 HY |
1924 | * Note that if it returns page table lock pointer, this routine returns without |
1925 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1926 | */ |
b6ec57f4 | 1927 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1928 | { |
b6ec57f4 KS |
1929 | spinlock_t *ptl; |
1930 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1931 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1932 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1933 | return ptl; |
1934 | spin_unlock(ptl); | |
1935 | return NULL; | |
cd7548ab JW |
1936 | } |
1937 | ||
a00cc7d9 MW |
1938 | /* |
1939 | * Returns true if a given pud maps a thp, false otherwise. | |
1940 | * | |
1941 | * Note that if it returns true, this routine returns without unlocking page | |
1942 | * table lock. So callers must unlock it. | |
1943 | */ | |
1944 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1945 | { | |
1946 | spinlock_t *ptl; | |
1947 | ||
1948 | ptl = pud_lock(vma->vm_mm, pud); | |
1949 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1950 | return ptl; | |
1951 | spin_unlock(ptl); | |
1952 | return NULL; | |
1953 | } | |
1954 | ||
1955 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1956 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1957 | pud_t *pud, unsigned long addr) | |
1958 | { | |
1959 | pud_t orig_pud; | |
1960 | spinlock_t *ptl; | |
1961 | ||
1962 | ptl = __pud_trans_huge_lock(pud, vma); | |
1963 | if (!ptl) | |
1964 | return 0; | |
1965 | /* | |
1966 | * For architectures like ppc64 we look at deposited pgtable | |
1967 | * when calling pudp_huge_get_and_clear. So do the | |
1968 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1969 | * operations. | |
1970 | */ | |
1971 | orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, | |
1972 | tlb->fullmm); | |
1973 | tlb_remove_pud_tlb_entry(tlb, pud, addr); | |
1974 | if (vma_is_dax(vma)) { | |
1975 | spin_unlock(ptl); | |
1976 | /* No zero page support yet */ | |
1977 | } else { | |
1978 | /* No support for anonymous PUD pages yet */ | |
1979 | BUG(); | |
1980 | } | |
1981 | return 1; | |
1982 | } | |
1983 | ||
1984 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1985 | unsigned long haddr) | |
1986 | { | |
1987 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1988 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1989 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1990 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1991 | ||
ce9311cf | 1992 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1993 | |
1994 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1995 | } | |
1996 | ||
1997 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1998 | unsigned long address) | |
1999 | { | |
2000 | spinlock_t *ptl; | |
2001 | struct mm_struct *mm = vma->vm_mm; | |
2002 | unsigned long haddr = address & HPAGE_PUD_MASK; | |
2003 | ||
2004 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PUD_SIZE); | |
2005 | ptl = pud_lock(mm, pud); | |
2006 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) | |
2007 | goto out; | |
2008 | __split_huge_pud_locked(vma, pud, haddr); | |
2009 | ||
2010 | out: | |
2011 | spin_unlock(ptl); | |
2012 | mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PUD_SIZE); | |
2013 | } | |
2014 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2015 | ||
eef1b3ba KS |
2016 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2017 | unsigned long haddr, pmd_t *pmd) | |
2018 | { | |
2019 | struct mm_struct *mm = vma->vm_mm; | |
2020 | pgtable_t pgtable; | |
2021 | pmd_t _pmd; | |
2022 | int i; | |
2023 | ||
2024 | /* leave pmd empty until pte is filled */ | |
2025 | pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
2026 | ||
2027 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2028 | pmd_populate(mm, &_pmd, pgtable); | |
2029 | ||
2030 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2031 | pte_t *pte, entry; | |
2032 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2033 | entry = pte_mkspecial(entry); | |
2034 | pte = pte_offset_map(&_pmd, haddr); | |
2035 | VM_BUG_ON(!pte_none(*pte)); | |
2036 | set_pte_at(mm, haddr, pte, entry); | |
2037 | pte_unmap(pte); | |
2038 | } | |
2039 | smp_wmb(); /* make pte visible before pmd */ | |
2040 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2041 | } |
2042 | ||
2043 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2044 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2045 | { |
2046 | struct mm_struct *mm = vma->vm_mm; | |
2047 | struct page *page; | |
2048 | pgtable_t pgtable; | |
2049 | pmd_t _pmd; | |
84c3fc4e | 2050 | bool young, write, dirty, soft_dirty, pmd_migration = false; |
2ac015e2 | 2051 | unsigned long addr; |
eef1b3ba KS |
2052 | int i; |
2053 | ||
2054 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2055 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2056 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2057 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2058 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2059 | |
2060 | count_vm_event(THP_SPLIT_PMD); | |
2061 | ||
d21b9e57 KS |
2062 | if (!vma_is_anonymous(vma)) { |
2063 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2064 | /* |
2065 | * We are going to unmap this huge page. So | |
2066 | * just go ahead and zap it | |
2067 | */ | |
2068 | if (arch_needs_pgtable_deposit()) | |
2069 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2070 | if (vma_is_dax(vma)) |
2071 | return; | |
2072 | page = pmd_page(_pmd); | |
70ef1db1 HD |
2073 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2074 | set_page_dirty(page); | |
d21b9e57 KS |
2075 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2076 | SetPageReferenced(page); | |
2077 | page_remove_rmap(page, true); | |
2078 | put_page(page); | |
2079 | add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); | |
eef1b3ba KS |
2080 | return; |
2081 | } else if (is_huge_zero_pmd(*pmd)) { | |
2082 | return __split_huge_zero_page_pmd(vma, haddr, pmd); | |
2083 | } | |
2084 | ||
84c3fc4e ZY |
2085 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
2086 | pmd_migration = is_pmd_migration_entry(*pmd); | |
2087 | if (pmd_migration) { | |
2088 | swp_entry_t entry; | |
2089 | ||
2090 | entry = pmd_to_swp_entry(*pmd); | |
2091 | page = pfn_to_page(swp_offset(entry)); | |
2092 | } else | |
2093 | #endif | |
2094 | page = pmd_page(*pmd); | |
eef1b3ba | 2095 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2096 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba KS |
2097 | write = pmd_write(*pmd); |
2098 | young = pmd_young(*pmd); | |
b8d3c4c3 | 2099 | dirty = pmd_dirty(*pmd); |
804dd150 | 2100 | soft_dirty = pmd_soft_dirty(*pmd); |
eef1b3ba | 2101 | |
c777e2a8 | 2102 | pmdp_huge_split_prepare(vma, haddr, pmd); |
eef1b3ba KS |
2103 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2104 | pmd_populate(mm, &_pmd, pgtable); | |
2105 | ||
2ac015e2 | 2106 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2107 | pte_t entry, *pte; |
2108 | /* | |
2109 | * Note that NUMA hinting access restrictions are not | |
2110 | * transferred to avoid any possibility of altering | |
2111 | * permissions across VMAs. | |
2112 | */ | |
84c3fc4e | 2113 | if (freeze || pmd_migration) { |
ba988280 KS |
2114 | swp_entry_t swp_entry; |
2115 | swp_entry = make_migration_entry(page + i, write); | |
2116 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2117 | if (soft_dirty) |
2118 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2119 | } else { |
6d2329f8 | 2120 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2121 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2122 | if (!write) |
2123 | entry = pte_wrprotect(entry); | |
2124 | if (!young) | |
2125 | entry = pte_mkold(entry); | |
804dd150 AA |
2126 | if (soft_dirty) |
2127 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2128 | } |
b8d3c4c3 MK |
2129 | if (dirty) |
2130 | SetPageDirty(page + i); | |
2ac015e2 | 2131 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2132 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2133 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2134 | atomic_inc(&page[i]._mapcount); |
2135 | pte_unmap(pte); | |
2136 | } | |
2137 | ||
2138 | /* | |
2139 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2140 | * false-negative page_mapped(). | |
2141 | */ | |
2142 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2143 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2144 | atomic_inc(&page[i]._mapcount); | |
2145 | } | |
2146 | ||
2147 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2148 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2149 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2150 | if (TestClearPageDoubleMap(page)) { |
2151 | /* No need in mapcount reference anymore */ | |
2152 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2153 | atomic_dec(&page[i]._mapcount); | |
2154 | } | |
2155 | } | |
2156 | ||
2157 | smp_wmb(); /* make pte visible before pmd */ | |
e9b61f19 KS |
2158 | /* |
2159 | * Up to this point the pmd is present and huge and userland has the | |
2160 | * whole access to the hugepage during the split (which happens in | |
2161 | * place). If we overwrite the pmd with the not-huge version pointing | |
2162 | * to the pte here (which of course we could if all CPUs were bug | |
2163 | * free), userland could trigger a small page size TLB miss on the | |
2164 | * small sized TLB while the hugepage TLB entry is still established in | |
2165 | * the huge TLB. Some CPU doesn't like that. | |
2166 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2167 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2168 | * only safe if the permission and cache attributes of the two entries | |
2169 | * loaded in the two TLB is identical (which should be the case here). | |
2170 | * But it is generally safer to never allow small and huge TLB entries | |
2171 | * for the same virtual address to be loaded simultaneously. So instead | |
2172 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2173 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2174 | * and pmd_trans_splitting must remain set at all times on the pmd | |
2175 | * until the split is complete for this pmd), then we flush the SMP TLB | |
2176 | * and finally we write the non-huge version of the pmd entry with | |
2177 | * pmd_populate. | |
2178 | */ | |
2179 | pmdp_invalidate(vma, haddr, pmd); | |
eef1b3ba | 2180 | pmd_populate(mm, pmd, pgtable); |
e9b61f19 KS |
2181 | |
2182 | if (freeze) { | |
2ac015e2 | 2183 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2184 | page_remove_rmap(page + i, false); |
2185 | put_page(page + i); | |
2186 | } | |
2187 | } | |
eef1b3ba KS |
2188 | } |
2189 | ||
2190 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2191 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2192 | { |
2193 | spinlock_t *ptl; | |
2194 | struct mm_struct *mm = vma->vm_mm; | |
2195 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
3b6c93db AA |
2196 | bool was_locked = false; |
2197 | pmd_t _pmd; | |
eef1b3ba KS |
2198 | |
2199 | mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE); | |
2200 | ptl = pmd_lock(mm, pmd); | |
33f4751e NH |
2201 | |
2202 | /* | |
2203 | * If caller asks to setup a migration entries, we need a page to check | |
2204 | * pmd against. Otherwise we can end up replacing wrong page. | |
2205 | */ | |
2206 | VM_BUG_ON(freeze && !page); | |
3b6c93db AA |
2207 | if (page) { |
2208 | VM_WARN_ON_ONCE(!PageLocked(page)); | |
2209 | was_locked = true; | |
2210 | if (page != pmd_page(*pmd)) | |
2211 | goto out; | |
2212 | } | |
33f4751e | 2213 | |
3b6c93db | 2214 | repeat: |
5c7fb56e | 2215 | if (pmd_trans_huge(*pmd)) { |
3b6c93db AA |
2216 | if (!page) { |
2217 | page = pmd_page(*pmd); | |
2218 | if (unlikely(!trylock_page(page))) { | |
2219 | get_page(page); | |
2220 | _pmd = *pmd; | |
2221 | spin_unlock(ptl); | |
2222 | lock_page(page); | |
2223 | spin_lock(ptl); | |
2224 | if (unlikely(!pmd_same(*pmd, _pmd))) { | |
2225 | unlock_page(page); | |
2226 | put_page(page); | |
2227 | page = NULL; | |
2228 | goto repeat; | |
2229 | } | |
2230 | put_page(page); | |
2231 | } | |
2232 | } | |
5c7fb56e | 2233 | if (PageMlocked(page)) |
5f737714 | 2234 | clear_page_mlock(page); |
84c3fc4e | 2235 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2236 | goto out; |
fec89c10 | 2237 | __split_huge_pmd_locked(vma, pmd, haddr, freeze); |
e90309c9 | 2238 | out: |
eef1b3ba | 2239 | spin_unlock(ptl); |
3b6c93db AA |
2240 | if (!was_locked && page) |
2241 | unlock_page(page); | |
eef1b3ba KS |
2242 | mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE); |
2243 | } | |
2244 | ||
fec89c10 KS |
2245 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2246 | bool freeze, struct page *page) | |
94fcc585 | 2247 | { |
f72e7dcd | 2248 | pgd_t *pgd; |
c2febafc | 2249 | p4d_t *p4d; |
f72e7dcd | 2250 | pud_t *pud; |
94fcc585 AA |
2251 | pmd_t *pmd; |
2252 | ||
78ddc534 | 2253 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2254 | if (!pgd_present(*pgd)) |
2255 | return; | |
2256 | ||
c2febafc KS |
2257 | p4d = p4d_offset(pgd, address); |
2258 | if (!p4d_present(*p4d)) | |
2259 | return; | |
2260 | ||
2261 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2262 | if (!pud_present(*pud)) |
2263 | return; | |
2264 | ||
2265 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2266 | |
33f4751e | 2267 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2268 | } |
2269 | ||
e1b9996b | 2270 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2271 | unsigned long start, |
2272 | unsigned long end, | |
2273 | long adjust_next) | |
2274 | { | |
2275 | /* | |
2276 | * If the new start address isn't hpage aligned and it could | |
2277 | * previously contain an hugepage: check if we need to split | |
2278 | * an huge pmd. | |
2279 | */ | |
2280 | if (start & ~HPAGE_PMD_MASK && | |
2281 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2282 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2283 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2284 | |
2285 | /* | |
2286 | * If the new end address isn't hpage aligned and it could | |
2287 | * previously contain an hugepage: check if we need to split | |
2288 | * an huge pmd. | |
2289 | */ | |
2290 | if (end & ~HPAGE_PMD_MASK && | |
2291 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2292 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2293 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2294 | |
2295 | /* | |
2296 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2297 | * vm_next->vm_start isn't page aligned and it could previously | |
2298 | * contain an hugepage: check if we need to split an huge pmd. | |
2299 | */ | |
2300 | if (adjust_next > 0) { | |
2301 | struct vm_area_struct *next = vma->vm_next; | |
2302 | unsigned long nstart = next->vm_start; | |
2303 | nstart += adjust_next << PAGE_SHIFT; | |
2304 | if (nstart & ~HPAGE_PMD_MASK && | |
2305 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2306 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2307 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2308 | } |
2309 | } | |
e9b61f19 | 2310 | |
e12b67d8 | 2311 | static void unmap_page(struct page *page) |
e9b61f19 | 2312 | { |
baa355fd | 2313 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2314 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2315 | bool unmap_success; |
e9b61f19 KS |
2316 | |
2317 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2318 | ||
baa355fd | 2319 | if (PageAnon(page)) |
b5ff8161 | 2320 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2321 | |
666e5a40 MK |
2322 | unmap_success = try_to_unmap(page, ttu_flags); |
2323 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2324 | } |
2325 | ||
e12b67d8 | 2326 | static void remap_page(struct page *page) |
e9b61f19 | 2327 | { |
fec89c10 | 2328 | int i; |
ace71a19 KS |
2329 | if (PageTransHuge(page)) { |
2330 | remove_migration_ptes(page, page, true); | |
2331 | } else { | |
2332 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2333 | remove_migration_ptes(page + i, page + i, true); | |
2334 | } | |
e9b61f19 KS |
2335 | } |
2336 | ||
8df651c7 | 2337 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2338 | struct lruvec *lruvec, struct list_head *list) |
2339 | { | |
e9b61f19 KS |
2340 | struct page *page_tail = head + tail; |
2341 | ||
8df651c7 | 2342 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2343 | |
2344 | /* | |
30241d72 KK |
2345 | * Clone page flags before unfreezing refcount. |
2346 | * | |
2347 | * After successful get_page_unless_zero() might follow flags change, | |
2348 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2349 | */ |
e9b61f19 KS |
2350 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2351 | page_tail->flags |= (head->flags & | |
2352 | ((1L << PG_referenced) | | |
2353 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2354 | (1L << PG_swapcache) | |
e9b61f19 KS |
2355 | (1L << PG_mlocked) | |
2356 | (1L << PG_uptodate) | | |
2357 | (1L << PG_active) | | |
2358 | (1L << PG_locked) | | |
b8d3c4c3 MK |
2359 | (1L << PG_unevictable) | |
2360 | (1L << PG_dirty))); | |
e9b61f19 | 2361 | |
16d07443 HD |
2362 | /* ->mapping in first tail page is compound_mapcount */ |
2363 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2364 | page_tail); | |
2365 | page_tail->mapping = head->mapping; | |
2366 | page_tail->index = head->index + tail; | |
2367 | ||
30241d72 | 2368 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2369 | smp_wmb(); |
2370 | ||
30241d72 KK |
2371 | /* |
2372 | * Clear PageTail before unfreezing page refcount. | |
2373 | * | |
2374 | * After successful get_page_unless_zero() might follow put_page() | |
2375 | * which needs correct compound_head(). | |
2376 | */ | |
e9b61f19 KS |
2377 | clear_compound_head(page_tail); |
2378 | ||
30241d72 KK |
2379 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2380 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2381 | PageSwapCache(head))); | |
2382 | ||
e9b61f19 KS |
2383 | if (page_is_young(head)) |
2384 | set_page_young(page_tail); | |
2385 | if (page_is_idle(head)) | |
2386 | set_page_idle(page_tail); | |
2387 | ||
e9b61f19 KS |
2388 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
2389 | lru_add_page_tail(head, page_tail, lruvec, list); | |
e9b61f19 KS |
2390 | } |
2391 | ||
baa355fd | 2392 | static void __split_huge_page(struct page *page, struct list_head *list, |
6f75a098 | 2393 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2394 | { |
2395 | struct page *head = compound_head(page); | |
2396 | struct zone *zone = page_zone(head); | |
2397 | struct lruvec *lruvec; | |
8df651c7 | 2398 | int i; |
e9b61f19 | 2399 | |
599d0c95 | 2400 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
2401 | |
2402 | /* complete memcg works before add pages to LRU */ | |
2403 | mem_cgroup_split_huge_fixup(head); | |
2404 | ||
baa355fd | 2405 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2406 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2407 | /* Some pages can be beyond i_size: drop them from page cache */ |
2408 | if (head[i].index >= end) { | |
a7027b7d | 2409 | ClearPageDirty(head + i); |
baa355fd | 2410 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2411 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2412 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2413 | put_page(head + i); |
2414 | } | |
2415 | } | |
e9b61f19 KS |
2416 | |
2417 | ClearPageCompound(head); | |
58eba200 VB |
2418 | |
2419 | split_page_owner(head, HPAGE_PMD_ORDER); | |
2420 | ||
baa355fd KS |
2421 | /* See comment in __split_huge_page_tail() */ |
2422 | if (PageAnon(head)) { | |
38d8b4e6 HY |
2423 | /* Additional pin to radix tree of swap cache */ |
2424 | if (PageSwapCache(head)) | |
2425 | page_ref_add(head, 2); | |
2426 | else | |
2427 | page_ref_inc(head); | |
baa355fd KS |
2428 | } else { |
2429 | /* Additional pin to radix tree */ | |
2430 | page_ref_add(head, 2); | |
2431 | spin_unlock(&head->mapping->tree_lock); | |
2432 | } | |
2433 | ||
a52633d8 | 2434 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 2435 | |
e12b67d8 | 2436 | remap_page(head); |
e9b61f19 KS |
2437 | |
2438 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2439 | struct page *subpage = head + i; | |
2440 | if (subpage == page) | |
2441 | continue; | |
2442 | unlock_page(subpage); | |
2443 | ||
2444 | /* | |
2445 | * Subpages may be freed if there wasn't any mapping | |
2446 | * like if add_to_swap() is running on a lru page that | |
2447 | * had its mapping zapped. And freeing these pages | |
2448 | * requires taking the lru_lock so we do the put_page | |
2449 | * of the tail pages after the split is complete. | |
2450 | */ | |
2451 | put_page(subpage); | |
2452 | } | |
2453 | } | |
2454 | ||
b20ce5e0 KS |
2455 | int total_mapcount(struct page *page) |
2456 | { | |
dd78fedd | 2457 | int i, compound, ret; |
b20ce5e0 KS |
2458 | |
2459 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2460 | ||
2461 | if (likely(!PageCompound(page))) | |
2462 | return atomic_read(&page->_mapcount) + 1; | |
2463 | ||
dd78fedd | 2464 | compound = compound_mapcount(page); |
b20ce5e0 | 2465 | if (PageHuge(page)) |
dd78fedd KS |
2466 | return compound; |
2467 | ret = compound; | |
b20ce5e0 KS |
2468 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2469 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2470 | /* File pages has compound_mapcount included in _mapcount */ |
2471 | if (!PageAnon(page)) | |
2472 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2473 | if (PageDoubleMap(page)) |
2474 | ret -= HPAGE_PMD_NR; | |
2475 | return ret; | |
2476 | } | |
2477 | ||
6d0a07ed AA |
2478 | /* |
2479 | * This calculates accurately how many mappings a transparent hugepage | |
2480 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2481 | * accuracy is primarily needed to know if copy-on-write faults can | |
2482 | * reuse the page and change the mapping to read-write instead of | |
2483 | * copying them. At the same time this returns the total_mapcount too. | |
2484 | * | |
2485 | * The function returns the highest mapcount any one of the subpages | |
2486 | * has. If the return value is one, even if different processes are | |
2487 | * mapping different subpages of the transparent hugepage, they can | |
2488 | * all reuse it, because each process is reusing a different subpage. | |
2489 | * | |
2490 | * The total_mapcount is instead counting all virtual mappings of the | |
2491 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2492 | * caller all mappings belong to the same "mm" and in turn the | |
2493 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2494 | * local one as no other process may be mapping any of the subpages. | |
2495 | * | |
2496 | * It would be more accurate to replace page_mapcount() with | |
2497 | * page_trans_huge_mapcount(), however we only use | |
2498 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2499 | * need full accuracy to avoid breaking page pinning, because | |
2500 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2501 | */ | |
2502 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2503 | { | |
2504 | int i, ret, _total_mapcount, mapcount; | |
2505 | ||
2506 | /* hugetlbfs shouldn't call it */ | |
2507 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2508 | ||
2509 | if (likely(!PageTransCompound(page))) { | |
2510 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2511 | if (total_mapcount) | |
2512 | *total_mapcount = mapcount; | |
2513 | return mapcount; | |
2514 | } | |
2515 | ||
2516 | page = compound_head(page); | |
2517 | ||
2518 | _total_mapcount = ret = 0; | |
2519 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2520 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2521 | ret = max(ret, mapcount); | |
2522 | _total_mapcount += mapcount; | |
2523 | } | |
2524 | if (PageDoubleMap(page)) { | |
2525 | ret -= 1; | |
2526 | _total_mapcount -= HPAGE_PMD_NR; | |
2527 | } | |
2528 | mapcount = compound_mapcount(page); | |
2529 | ret += mapcount; | |
2530 | _total_mapcount += mapcount; | |
2531 | if (total_mapcount) | |
2532 | *total_mapcount = _total_mapcount; | |
2533 | return ret; | |
2534 | } | |
2535 | ||
b8f593cd HY |
2536 | /* Racy check whether the huge page can be split */ |
2537 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2538 | { | |
2539 | int extra_pins; | |
2540 | ||
2541 | /* Additional pins from radix tree */ | |
2542 | if (PageAnon(page)) | |
2543 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2544 | else | |
2545 | extra_pins = HPAGE_PMD_NR; | |
2546 | if (pextra_pins) | |
2547 | *pextra_pins = extra_pins; | |
2548 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2549 | } | |
2550 | ||
e9b61f19 KS |
2551 | /* |
2552 | * This function splits huge page into normal pages. @page can point to any | |
2553 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2554 | * | |
2555 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2556 | * The huge page must be locked. | |
2557 | * | |
2558 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2559 | * | |
2560 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2561 | * the hugepage. | |
2562 | * | |
2563 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2564 | * they are not mapped. | |
2565 | * | |
2566 | * Returns 0 if the hugepage is split successfully. | |
2567 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2568 | * us. | |
2569 | */ | |
2570 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2571 | { | |
2572 | struct page *head = compound_head(page); | |
a3d0a918 | 2573 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2574 | struct anon_vma *anon_vma = NULL; |
2575 | struct address_space *mapping = NULL; | |
2576 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2577 | bool mlocked; |
0b9b6fff | 2578 | unsigned long flags; |
6f75a098 | 2579 | pgoff_t end; |
e9b61f19 | 2580 | |
b200a5dd | 2581 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
e9b61f19 | 2582 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2583 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2584 | ||
59807685 HY |
2585 | if (PageWriteback(page)) |
2586 | return -EBUSY; | |
2587 | ||
baa355fd KS |
2588 | if (PageAnon(head)) { |
2589 | /* | |
2590 | * The caller does not necessarily hold an mmap_sem that would | |
2591 | * prevent the anon_vma disappearing so we first we take a | |
2592 | * reference to it and then lock the anon_vma for write. This | |
2593 | * is similar to page_lock_anon_vma_read except the write lock | |
2594 | * is taken to serialise against parallel split or collapse | |
2595 | * operations. | |
2596 | */ | |
2597 | anon_vma = page_get_anon_vma(head); | |
2598 | if (!anon_vma) { | |
2599 | ret = -EBUSY; | |
2600 | goto out; | |
2601 | } | |
6f75a098 | 2602 | end = -1; |
baa355fd KS |
2603 | mapping = NULL; |
2604 | anon_vma_lock_write(anon_vma); | |
2605 | } else { | |
2606 | mapping = head->mapping; | |
2607 | ||
2608 | /* Truncated ? */ | |
2609 | if (!mapping) { | |
2610 | ret = -EBUSY; | |
2611 | goto out; | |
2612 | } | |
2613 | ||
baa355fd KS |
2614 | anon_vma = NULL; |
2615 | i_mmap_lock_read(mapping); | |
6f75a098 HD |
2616 | |
2617 | /* | |
2618 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2619 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2620 | * which cannot be nested inside the page tree lock. So note | |
2621 | * end now: i_size itself may be changed at any moment, but | |
2622 | * head page lock is good enough to serialize the trimming. | |
2623 | */ | |
2624 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2625 | } |
e9b61f19 KS |
2626 | |
2627 | /* | |
e12b67d8 | 2628 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2629 | * split PMDs |
2630 | */ | |
b8f593cd | 2631 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2632 | ret = -EBUSY; |
2633 | goto out_unlock; | |
2634 | } | |
2635 | ||
d9654322 | 2636 | mlocked = PageMlocked(page); |
e12b67d8 | 2637 | unmap_page(head); |
e9b61f19 KS |
2638 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2639 | ||
d9654322 KS |
2640 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2641 | if (mlocked) | |
2642 | lru_add_drain(); | |
2643 | ||
baa355fd | 2644 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2645 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2646 | |
2647 | if (mapping) { | |
2648 | void **pslot; | |
2649 | ||
2650 | spin_lock(&mapping->tree_lock); | |
2651 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
2652 | page_index(head)); | |
2653 | /* | |
2654 | * Check if the head page is present in radix tree. | |
2655 | * We assume all tail are present too, if head is there. | |
2656 | */ | |
2657 | if (radix_tree_deref_slot_protected(pslot, | |
2658 | &mapping->tree_lock) != head) | |
2659 | goto fail; | |
2660 | } | |
2661 | ||
0139aa7b | 2662 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2663 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2664 | count = page_count(head); |
2665 | mapcount = total_mapcount(head); | |
baa355fd | 2666 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2667 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2668 | pgdata->split_queue_len--; |
9a982250 KS |
2669 | list_del(page_deferred_list(head)); |
2670 | } | |
65c45377 | 2671 | if (mapping) |
11fb9989 | 2672 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd | 2673 | spin_unlock(&pgdata->split_queue_lock); |
6f75a098 | 2674 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2675 | if (PageSwapCache(head)) { |
2676 | swp_entry_t entry = { .val = page_private(head) }; | |
2677 | ||
2678 | ret = split_swap_cluster(entry); | |
2679 | } else | |
2680 | ret = 0; | |
e9b61f19 | 2681 | } else { |
baa355fd KS |
2682 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2683 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2684 | mapcount, count); | |
2685 | if (PageTail(page)) | |
2686 | dump_page(head, NULL); | |
2687 | dump_page(page, "total_mapcount(head) > 0"); | |
2688 | BUG(); | |
2689 | } | |
2690 | spin_unlock(&pgdata->split_queue_lock); | |
2691 | fail: if (mapping) | |
2692 | spin_unlock(&mapping->tree_lock); | |
a52633d8 | 2693 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e12b67d8 | 2694 | remap_page(head); |
e9b61f19 KS |
2695 | ret = -EBUSY; |
2696 | } | |
2697 | ||
2698 | out_unlock: | |
baa355fd KS |
2699 | if (anon_vma) { |
2700 | anon_vma_unlock_write(anon_vma); | |
2701 | put_anon_vma(anon_vma); | |
2702 | } | |
2703 | if (mapping) | |
2704 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2705 | out: |
2706 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2707 | return ret; | |
2708 | } | |
9a982250 KS |
2709 | |
2710 | void free_transhuge_page(struct page *page) | |
2711 | { | |
a3d0a918 | 2712 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2713 | unsigned long flags; |
2714 | ||
a3d0a918 | 2715 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2716 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2717 | pgdata->split_queue_len--; |
9a982250 KS |
2718 | list_del(page_deferred_list(page)); |
2719 | } | |
a3d0a918 | 2720 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2721 | free_compound_page(page); |
2722 | } | |
2723 | ||
2724 | void deferred_split_huge_page(struct page *page) | |
2725 | { | |
a3d0a918 | 2726 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2727 | unsigned long flags; |
2728 | ||
2729 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2730 | ||
a3d0a918 | 2731 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2732 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2733 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2734 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2735 | pgdata->split_queue_len++; | |
9a982250 | 2736 | } |
a3d0a918 | 2737 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2738 | } |
2739 | ||
2740 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2741 | struct shrink_control *sc) | |
2742 | { | |
a3d0a918 | 2743 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
cb8d68ec | 2744 | return ACCESS_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2745 | } |
2746 | ||
2747 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2748 | struct shrink_control *sc) | |
2749 | { | |
a3d0a918 | 2750 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2751 | unsigned long flags; |
2752 | LIST_HEAD(list), *pos, *next; | |
2753 | struct page *page; | |
2754 | int split = 0; | |
2755 | ||
a3d0a918 | 2756 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2757 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2758 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2759 | page = list_entry((void *)pos, struct page, mapping); |
2760 | page = compound_head(page); | |
e3ae1953 KS |
2761 | if (get_page_unless_zero(page)) { |
2762 | list_move(page_deferred_list(page), &list); | |
2763 | } else { | |
2764 | /* We lost race with put_compound_page() */ | |
9a982250 | 2765 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2766 | pgdata->split_queue_len--; |
9a982250 | 2767 | } |
e3ae1953 KS |
2768 | if (!--sc->nr_to_scan) |
2769 | break; | |
9a982250 | 2770 | } |
a3d0a918 | 2771 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2772 | |
2773 | list_for_each_safe(pos, next, &list) { | |
2774 | page = list_entry((void *)pos, struct page, mapping); | |
b6b6783c KS |
2775 | if (!trylock_page(page)) |
2776 | goto next; | |
9a982250 KS |
2777 | /* split_huge_page() removes page from list on success */ |
2778 | if (!split_huge_page(page)) | |
2779 | split++; | |
2780 | unlock_page(page); | |
b6b6783c | 2781 | next: |
9a982250 KS |
2782 | put_page(page); |
2783 | } | |
2784 | ||
a3d0a918 KS |
2785 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2786 | list_splice_tail(&list, &pgdata->split_queue); | |
2787 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2788 | |
cb8d68ec KS |
2789 | /* |
2790 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2791 | * This can happen if pages were freed under us. | |
2792 | */ | |
2793 | if (!split && list_empty(&pgdata->split_queue)) | |
2794 | return SHRINK_STOP; | |
2795 | return split; | |
9a982250 KS |
2796 | } |
2797 | ||
2798 | static struct shrinker deferred_split_shrinker = { | |
2799 | .count_objects = deferred_split_count, | |
2800 | .scan_objects = deferred_split_scan, | |
2801 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2802 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2803 | }; |
49071d43 KS |
2804 | |
2805 | #ifdef CONFIG_DEBUG_FS | |
2806 | static int split_huge_pages_set(void *data, u64 val) | |
2807 | { | |
2808 | struct zone *zone; | |
2809 | struct page *page; | |
2810 | unsigned long pfn, max_zone_pfn; | |
2811 | unsigned long total = 0, split = 0; | |
2812 | ||
2813 | if (val != 1) | |
2814 | return -EINVAL; | |
2815 | ||
2816 | for_each_populated_zone(zone) { | |
2817 | max_zone_pfn = zone_end_pfn(zone); | |
2818 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2819 | if (!pfn_valid(pfn)) | |
2820 | continue; | |
2821 | ||
2822 | page = pfn_to_page(pfn); | |
2823 | if (!get_page_unless_zero(page)) | |
2824 | continue; | |
2825 | ||
2826 | if (zone != page_zone(page)) | |
2827 | goto next; | |
2828 | ||
baa355fd | 2829 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2830 | goto next; |
2831 | ||
2832 | total++; | |
2833 | lock_page(page); | |
2834 | if (!split_huge_page(page)) | |
2835 | split++; | |
2836 | unlock_page(page); | |
2837 | next: | |
2838 | put_page(page); | |
2839 | } | |
2840 | } | |
2841 | ||
145bdaa1 | 2842 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2843 | |
2844 | return 0; | |
2845 | } | |
2846 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2847 | "%llu\n"); | |
2848 | ||
2849 | static int __init split_huge_pages_debugfs(void) | |
2850 | { | |
2851 | void *ret; | |
2852 | ||
145bdaa1 | 2853 | ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
49071d43 KS |
2854 | &split_huge_pages_fops); |
2855 | if (!ret) | |
2856 | pr_warn("Failed to create split_huge_pages in debugfs"); | |
2857 | return 0; | |
2858 | } | |
2859 | late_initcall(split_huge_pages_debugfs); | |
2860 | #endif | |
616b8371 ZY |
2861 | |
2862 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2863 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2864 | struct page *page) | |
2865 | { | |
2866 | struct vm_area_struct *vma = pvmw->vma; | |
2867 | struct mm_struct *mm = vma->vm_mm; | |
2868 | unsigned long address = pvmw->address; | |
2869 | pmd_t pmdval; | |
2870 | swp_entry_t entry; | |
ab6e3d09 | 2871 | pmd_t pmdswp; |
616b8371 ZY |
2872 | |
2873 | if (!(pvmw->pmd && !pvmw->pte)) | |
2874 | return; | |
2875 | ||
616b8371 ZY |
2876 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
2877 | pmdval = *pvmw->pmd; | |
2878 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2879 | if (pmd_dirty(pmdval)) | |
2880 | set_page_dirty(page); | |
2881 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2882 | pmdswp = swp_entry_to_pmd(entry); |
2883 | if (pmd_soft_dirty(pmdval)) | |
2884 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2885 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2886 | page_remove_rmap(page, true); |
2887 | put_page(page); | |
616b8371 ZY |
2888 | } |
2889 | ||
2890 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2891 | { | |
2892 | struct vm_area_struct *vma = pvmw->vma; | |
2893 | struct mm_struct *mm = vma->vm_mm; | |
2894 | unsigned long address = pvmw->address; | |
2895 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2896 | pmd_t pmde; | |
2897 | swp_entry_t entry; | |
2898 | ||
2899 | if (!(pvmw->pmd && !pvmw->pte)) | |
2900 | return; | |
2901 | ||
2902 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2903 | get_page(new); | |
2904 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2905 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2906 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 ZY |
2907 | if (is_write_migration_entry(entry)) |
2908 | pmde = maybe_pmd_mkwrite(pmde, vma); | |
2909 | ||
2910 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
2911 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2912 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); | |
a2e0493f | 2913 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
2914 | mlock_vma_page(new); |
2915 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
2916 | } | |
2917 | #endif |