Commit | Line | Data |
---|---|---|
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> |
98fa15f3 | 36 | #include <linux/numa.h> |
97ae1749 | 37 | |
71e3aac0 AA |
38 | #include <asm/tlb.h> |
39 | #include <asm/pgalloc.h> | |
40 | #include "internal.h" | |
41 | ||
ba76149f | 42 | /* |
b14d595a MD |
43 | * By default, transparent hugepage support is disabled in order to avoid |
44 | * risking an increased memory footprint for applications that are not | |
45 | * guaranteed to benefit from it. When transparent hugepage support is | |
46 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
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 | |
7635d9cb MH |
66 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
67 | { | |
68 | if (vma_is_anonymous(vma)) | |
69 | return __transparent_hugepage_enabled(vma); | |
70 | if (vma_is_shmem(vma) && shmem_huge_enabled(vma)) | |
71 | return __transparent_hugepage_enabled(vma); | |
72 | ||
73 | return false; | |
74 | } | |
75 | ||
6fcb52a5 | 76 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
77 | { |
78 | struct page *zero_page; | |
79 | retry: | |
80 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 81 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
82 | |
83 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 84 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
85 | if (!zero_page) { |
86 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 87 | return NULL; |
d8a8e1f0 KS |
88 | } |
89 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 90 | preempt_disable(); |
5918d10a | 91 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 92 | preempt_enable(); |
5ddacbe9 | 93 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
94 | goto retry; |
95 | } | |
96 | ||
97 | /* We take additional reference here. It will be put back by shrinker */ | |
98 | atomic_set(&huge_zero_refcount, 2); | |
99 | preempt_enable(); | |
4db0c3c2 | 100 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
101 | } |
102 | ||
6fcb52a5 | 103 | static void put_huge_zero_page(void) |
4a6c1297 | 104 | { |
97ae1749 KS |
105 | /* |
106 | * Counter should never go to zero here. Only shrinker can put | |
107 | * last reference. | |
108 | */ | |
109 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
110 | } |
111 | ||
6fcb52a5 AL |
112 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
113 | { | |
114 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
115 | return READ_ONCE(huge_zero_page); | |
116 | ||
117 | if (!get_huge_zero_page()) | |
118 | return NULL; | |
119 | ||
120 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
121 | put_huge_zero_page(); | |
122 | ||
123 | return READ_ONCE(huge_zero_page); | |
124 | } | |
125 | ||
126 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
127 | { | |
128 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
129 | put_huge_zero_page(); | |
130 | } | |
131 | ||
48896466 GC |
132 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
133 | struct shrink_control *sc) | |
4a6c1297 | 134 | { |
48896466 GC |
135 | /* we can free zero page only if last reference remains */ |
136 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
137 | } | |
97ae1749 | 138 | |
48896466 GC |
139 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
140 | struct shrink_control *sc) | |
141 | { | |
97ae1749 | 142 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
143 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
144 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 145 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 146 | return HPAGE_PMD_NR; |
97ae1749 KS |
147 | } |
148 | ||
149 | return 0; | |
4a6c1297 KS |
150 | } |
151 | ||
97ae1749 | 152 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
153 | .count_objects = shrink_huge_zero_page_count, |
154 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
155 | .seeks = DEFAULT_SEEKS, |
156 | }; | |
157 | ||
71e3aac0 | 158 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
159 | static ssize_t enabled_show(struct kobject *kobj, |
160 | struct kobj_attribute *attr, char *buf) | |
161 | { | |
444eb2a4 MG |
162 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
163 | return sprintf(buf, "[always] madvise never\n"); | |
164 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
165 | return sprintf(buf, "always [madvise] never\n"); | |
166 | else | |
167 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 168 | } |
444eb2a4 | 169 | |
71e3aac0 AA |
170 | static ssize_t enabled_store(struct kobject *kobj, |
171 | struct kobj_attribute *attr, | |
172 | const char *buf, size_t count) | |
173 | { | |
21440d7e | 174 | ssize_t ret = count; |
ba76149f | 175 | |
21440d7e DR |
176 | if (!memcmp("always", buf, |
177 | min(sizeof("always")-1, count))) { | |
178 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
179 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
180 | } else if (!memcmp("madvise", buf, | |
181 | min(sizeof("madvise")-1, count))) { | |
182 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
183 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
184 | } else if (!memcmp("never", buf, | |
185 | min(sizeof("never")-1, count))) { | |
186 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
187 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
188 | } else | |
189 | ret = -EINVAL; | |
ba76149f AA |
190 | |
191 | if (ret > 0) { | |
b46e756f | 192 | int err = start_stop_khugepaged(); |
ba76149f AA |
193 | if (err) |
194 | ret = err; | |
195 | } | |
ba76149f | 196 | return ret; |
71e3aac0 AA |
197 | } |
198 | static struct kobj_attribute enabled_attr = | |
199 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
200 | ||
b46e756f | 201 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
202 | struct kobj_attribute *attr, char *buf, |
203 | enum transparent_hugepage_flag flag) | |
204 | { | |
e27e6151 BH |
205 | return sprintf(buf, "%d\n", |
206 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 207 | } |
e27e6151 | 208 | |
b46e756f | 209 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
210 | struct kobj_attribute *attr, |
211 | const char *buf, size_t count, | |
212 | enum transparent_hugepage_flag flag) | |
213 | { | |
e27e6151 BH |
214 | unsigned long value; |
215 | int ret; | |
216 | ||
217 | ret = kstrtoul(buf, 10, &value); | |
218 | if (ret < 0) | |
219 | return ret; | |
220 | if (value > 1) | |
221 | return -EINVAL; | |
222 | ||
223 | if (value) | |
71e3aac0 | 224 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 225 | else |
71e3aac0 | 226 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
227 | |
228 | return count; | |
229 | } | |
230 | ||
71e3aac0 AA |
231 | static ssize_t defrag_show(struct kobject *kobj, |
232 | struct kobj_attribute *attr, char *buf) | |
233 | { | |
444eb2a4 | 234 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 235 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 236 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
237 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
238 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
239 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
240 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
241 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
242 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 243 | } |
21440d7e | 244 | |
71e3aac0 AA |
245 | static ssize_t defrag_store(struct kobject *kobj, |
246 | struct kobj_attribute *attr, | |
247 | const char *buf, size_t count) | |
248 | { | |
21440d7e DR |
249 | if (!memcmp("always", buf, |
250 | min(sizeof("always")-1, count))) { | |
251 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
252 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
253 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
254 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
255 | } else if (!memcmp("defer+madvise", buf, |
256 | min(sizeof("defer+madvise")-1, count))) { | |
257 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
258 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
259 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
260 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
4fad7fb6 DR |
261 | } else if (!memcmp("defer", buf, |
262 | min(sizeof("defer")-1, count))) { | |
263 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
264 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
265 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
266 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
21440d7e DR |
267 | } else if (!memcmp("madvise", buf, |
268 | min(sizeof("madvise")-1, count))) { | |
269 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
270 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
271 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
272 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
273 | } else if (!memcmp("never", buf, | |
274 | min(sizeof("never")-1, count))) { | |
275 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
276 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
277 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
278 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
279 | } else | |
280 | return -EINVAL; | |
281 | ||
282 | return count; | |
71e3aac0 AA |
283 | } |
284 | static struct kobj_attribute defrag_attr = | |
285 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
286 | ||
79da5407 KS |
287 | static ssize_t use_zero_page_show(struct kobject *kobj, |
288 | struct kobj_attribute *attr, char *buf) | |
289 | { | |
b46e756f | 290 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
291 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
292 | } | |
293 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
294 | struct kobj_attribute *attr, const char *buf, size_t count) | |
295 | { | |
b46e756f | 296 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
297 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
298 | } | |
299 | static struct kobj_attribute use_zero_page_attr = | |
300 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
301 | |
302 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
303 | struct kobj_attribute *attr, char *buf) | |
304 | { | |
305 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
306 | } | |
307 | static struct kobj_attribute hpage_pmd_size_attr = | |
308 | __ATTR_RO(hpage_pmd_size); | |
309 | ||
71e3aac0 AA |
310 | #ifdef CONFIG_DEBUG_VM |
311 | static ssize_t debug_cow_show(struct kobject *kobj, | |
312 | struct kobj_attribute *attr, char *buf) | |
313 | { | |
b46e756f | 314 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
315 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
316 | } | |
317 | static ssize_t debug_cow_store(struct kobject *kobj, | |
318 | struct kobj_attribute *attr, | |
319 | const char *buf, size_t count) | |
320 | { | |
b46e756f | 321 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
322 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
323 | } | |
324 | static struct kobj_attribute debug_cow_attr = | |
325 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
326 | #endif /* CONFIG_DEBUG_VM */ | |
327 | ||
328 | static struct attribute *hugepage_attr[] = { | |
329 | &enabled_attr.attr, | |
330 | &defrag_attr.attr, | |
79da5407 | 331 | &use_zero_page_attr.attr, |
49920d28 | 332 | &hpage_pmd_size_attr.attr, |
e496cf3d | 333 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
334 | &shmem_enabled_attr.attr, |
335 | #endif | |
71e3aac0 AA |
336 | #ifdef CONFIG_DEBUG_VM |
337 | &debug_cow_attr.attr, | |
338 | #endif | |
339 | NULL, | |
340 | }; | |
341 | ||
8aa95a21 | 342 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 343 | .attrs = hugepage_attr, |
ba76149f AA |
344 | }; |
345 | ||
569e5590 | 346 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 347 | { |
71e3aac0 AA |
348 | int err; |
349 | ||
569e5590 SL |
350 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
351 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 352 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 353 | return -ENOMEM; |
ba76149f AA |
354 | } |
355 | ||
569e5590 | 356 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 357 | if (err) { |
ae3a8c1c | 358 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 359 | goto delete_obj; |
ba76149f AA |
360 | } |
361 | ||
569e5590 | 362 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 363 | if (err) { |
ae3a8c1c | 364 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 365 | goto remove_hp_group; |
ba76149f | 366 | } |
569e5590 SL |
367 | |
368 | return 0; | |
369 | ||
370 | remove_hp_group: | |
371 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
372 | delete_obj: | |
373 | kobject_put(*hugepage_kobj); | |
374 | return err; | |
375 | } | |
376 | ||
377 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
378 | { | |
379 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
380 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
381 | kobject_put(hugepage_kobj); | |
382 | } | |
383 | #else | |
384 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
385 | { | |
386 | return 0; | |
387 | } | |
388 | ||
389 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
390 | { | |
391 | } | |
392 | #endif /* CONFIG_SYSFS */ | |
393 | ||
394 | static int __init hugepage_init(void) | |
395 | { | |
396 | int err; | |
397 | struct kobject *hugepage_kobj; | |
398 | ||
399 | if (!has_transparent_hugepage()) { | |
400 | transparent_hugepage_flags = 0; | |
401 | return -EINVAL; | |
402 | } | |
403 | ||
ff20c2e0 KS |
404 | /* |
405 | * hugepages can't be allocated by the buddy allocator | |
406 | */ | |
407 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
408 | /* | |
409 | * we use page->mapping and page->index in second tail page | |
410 | * as list_head: assuming THP order >= 2 | |
411 | */ | |
412 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
413 | ||
569e5590 SL |
414 | err = hugepage_init_sysfs(&hugepage_kobj); |
415 | if (err) | |
65ebb64f | 416 | goto err_sysfs; |
ba76149f | 417 | |
b46e756f | 418 | err = khugepaged_init(); |
ba76149f | 419 | if (err) |
65ebb64f | 420 | goto err_slab; |
ba76149f | 421 | |
65ebb64f KS |
422 | err = register_shrinker(&huge_zero_page_shrinker); |
423 | if (err) | |
424 | goto err_hzp_shrinker; | |
9a982250 KS |
425 | err = register_shrinker(&deferred_split_shrinker); |
426 | if (err) | |
427 | goto err_split_shrinker; | |
97ae1749 | 428 | |
97562cd2 RR |
429 | /* |
430 | * By default disable transparent hugepages on smaller systems, | |
431 | * where the extra memory used could hurt more than TLB overhead | |
432 | * is likely to save. The admin can still enable it through /sys. | |
433 | */ | |
ca79b0c2 | 434 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 435 | transparent_hugepage_flags = 0; |
79553da2 KS |
436 | return 0; |
437 | } | |
97562cd2 | 438 | |
79553da2 | 439 | err = start_stop_khugepaged(); |
65ebb64f KS |
440 | if (err) |
441 | goto err_khugepaged; | |
ba76149f | 442 | |
569e5590 | 443 | return 0; |
65ebb64f | 444 | err_khugepaged: |
9a982250 KS |
445 | unregister_shrinker(&deferred_split_shrinker); |
446 | err_split_shrinker: | |
65ebb64f KS |
447 | unregister_shrinker(&huge_zero_page_shrinker); |
448 | err_hzp_shrinker: | |
b46e756f | 449 | khugepaged_destroy(); |
65ebb64f | 450 | err_slab: |
569e5590 | 451 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 452 | err_sysfs: |
ba76149f | 453 | return err; |
71e3aac0 | 454 | } |
a64fb3cd | 455 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
456 | |
457 | static int __init setup_transparent_hugepage(char *str) | |
458 | { | |
459 | int ret = 0; | |
460 | if (!str) | |
461 | goto out; | |
462 | if (!strcmp(str, "always")) { | |
463 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
464 | &transparent_hugepage_flags); | |
465 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
466 | &transparent_hugepage_flags); | |
467 | ret = 1; | |
468 | } else if (!strcmp(str, "madvise")) { | |
469 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
470 | &transparent_hugepage_flags); | |
471 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
472 | &transparent_hugepage_flags); | |
473 | ret = 1; | |
474 | } else if (!strcmp(str, "never")) { | |
475 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
476 | &transparent_hugepage_flags); | |
477 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
478 | &transparent_hugepage_flags); | |
479 | ret = 1; | |
480 | } | |
481 | out: | |
482 | if (!ret) | |
ae3a8c1c | 483 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
484 | return ret; |
485 | } | |
486 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
487 | ||
f55e1014 | 488 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 489 | { |
f55e1014 | 490 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
491 | pmd = pmd_mkwrite(pmd); |
492 | return pmd; | |
493 | } | |
494 | ||
9a982250 KS |
495 | static inline struct list_head *page_deferred_list(struct page *page) |
496 | { | |
fa3015b7 MW |
497 | /* ->lru in the tail pages is occupied by compound_head. */ |
498 | return &page[2].deferred_list; | |
9a982250 KS |
499 | } |
500 | ||
501 | void prep_transhuge_page(struct page *page) | |
502 | { | |
503 | /* | |
504 | * we use page->mapping and page->indexlru in second tail page | |
505 | * as list_head: assuming THP order >= 2 | |
506 | */ | |
9a982250 KS |
507 | |
508 | INIT_LIST_HEAD(page_deferred_list(page)); | |
509 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
510 | } | |
511 | ||
74d2fad1 TK |
512 | unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len, |
513 | loff_t off, unsigned long flags, unsigned long size) | |
514 | { | |
515 | unsigned long addr; | |
516 | loff_t off_end = off + len; | |
517 | loff_t off_align = round_up(off, size); | |
518 | unsigned long len_pad; | |
519 | ||
520 | if (off_end <= off_align || (off_end - off_align) < size) | |
521 | return 0; | |
522 | ||
523 | len_pad = len + size; | |
524 | if (len_pad < len || (off + len_pad) < off) | |
525 | return 0; | |
526 | ||
527 | addr = current->mm->get_unmapped_area(filp, 0, len_pad, | |
528 | off >> PAGE_SHIFT, flags); | |
529 | if (IS_ERR_VALUE(addr)) | |
530 | return 0; | |
531 | ||
532 | addr += (off - addr) & (size - 1); | |
533 | return addr; | |
534 | } | |
535 | ||
536 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
537 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
538 | { | |
539 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; | |
540 | ||
541 | if (addr) | |
542 | goto out; | |
543 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) | |
544 | goto out; | |
545 | ||
546 | addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE); | |
547 | if (addr) | |
548 | return addr; | |
549 | ||
550 | out: | |
551 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); | |
552 | } | |
553 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
554 | ||
2b740303 SJ |
555 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
556 | struct page *page, gfp_t gfp) | |
71e3aac0 | 557 | { |
82b0f8c3 | 558 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 559 | struct mem_cgroup *memcg; |
71e3aac0 | 560 | pgtable_t pgtable; |
82b0f8c3 | 561 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 562 | vm_fault_t ret = 0; |
71e3aac0 | 563 | |
309381fe | 564 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 565 | |
2cf85583 | 566 | if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
567 | put_page(page); |
568 | count_vm_event(THP_FAULT_FALLBACK); | |
569 | return VM_FAULT_FALLBACK; | |
570 | } | |
00501b53 | 571 | |
4cf58924 | 572 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 573 | if (unlikely(!pgtable)) { |
6b31d595 MH |
574 | ret = VM_FAULT_OOM; |
575 | goto release; | |
00501b53 | 576 | } |
71e3aac0 | 577 | |
c79b57e4 | 578 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
579 | /* |
580 | * The memory barrier inside __SetPageUptodate makes sure that | |
581 | * clear_huge_page writes become visible before the set_pmd_at() | |
582 | * write. | |
583 | */ | |
71e3aac0 AA |
584 | __SetPageUptodate(page); |
585 | ||
82b0f8c3 JK |
586 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
587 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 588 | goto unlock_release; |
71e3aac0 AA |
589 | } else { |
590 | pmd_t entry; | |
6b251fc9 | 591 | |
6b31d595 MH |
592 | ret = check_stable_address_space(vma->vm_mm); |
593 | if (ret) | |
594 | goto unlock_release; | |
595 | ||
6b251fc9 AA |
596 | /* Deliver the page fault to userland */ |
597 | if (userfaultfd_missing(vma)) { | |
2b740303 | 598 | vm_fault_t ret2; |
6b251fc9 | 599 | |
82b0f8c3 | 600 | spin_unlock(vmf->ptl); |
f627c2f5 | 601 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 602 | put_page(page); |
bae473a4 | 603 | pte_free(vma->vm_mm, pgtable); |
2b740303 SJ |
604 | ret2 = handle_userfault(vmf, VM_UFFD_MISSING); |
605 | VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); | |
606 | return ret2; | |
6b251fc9 AA |
607 | } |
608 | ||
3122359a | 609 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 610 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 611 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 612 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 613 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
614 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
615 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 616 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 617 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 618 | spin_unlock(vmf->ptl); |
6b251fc9 | 619 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 620 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
71e3aac0 AA |
621 | } |
622 | ||
aa2e878e | 623 | return 0; |
6b31d595 MH |
624 | unlock_release: |
625 | spin_unlock(vmf->ptl); | |
626 | release: | |
627 | if (pgtable) | |
628 | pte_free(vma->vm_mm, pgtable); | |
629 | mem_cgroup_cancel_charge(page, memcg, true); | |
630 | put_page(page); | |
631 | return ret; | |
632 | ||
71e3aac0 AA |
633 | } |
634 | ||
444eb2a4 | 635 | /* |
21440d7e DR |
636 | * always: directly stall for all thp allocations |
637 | * defer: wake kswapd and fail if not immediately available | |
638 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
639 | * fail if not immediately available | |
640 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
641 | * available | |
642 | * never: never stall for any thp allocation | |
444eb2a4 | 643 | */ |
356ff8a9 | 644 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) |
444eb2a4 | 645 | { |
21440d7e | 646 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
25160354 | 647 | |
2f0799a0 | 648 | /* Always do synchronous compaction */ |
21440d7e | 649 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 650 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); |
2f0799a0 DR |
651 | |
652 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 653 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
356ff8a9 | 654 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
2f0799a0 DR |
655 | |
656 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 657 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
658 | return GFP_TRANSHUGE_LIGHT | |
659 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
660 | __GFP_KSWAPD_RECLAIM); | |
2f0799a0 DR |
661 | |
662 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 663 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
356ff8a9 DR |
664 | return GFP_TRANSHUGE_LIGHT | |
665 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
2f0799a0 | 666 | |
356ff8a9 | 667 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
668 | } |
669 | ||
c4088ebd | 670 | /* Caller must hold page table lock. */ |
d295e341 | 671 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 672 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 673 | struct page *zero_page) |
fc9fe822 KS |
674 | { |
675 | pmd_t entry; | |
7c414164 AM |
676 | if (!pmd_none(*pmd)) |
677 | return false; | |
5918d10a | 678 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 679 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
680 | if (pgtable) |
681 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 682 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 683 | mm_inc_nr_ptes(mm); |
7c414164 | 684 | return true; |
fc9fe822 KS |
685 | } |
686 | ||
2b740303 | 687 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 688 | { |
82b0f8c3 | 689 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 690 | gfp_t gfp; |
71e3aac0 | 691 | struct page *page; |
82b0f8c3 | 692 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 693 | |
128ec037 | 694 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 695 | return VM_FAULT_FALLBACK; |
128ec037 KS |
696 | if (unlikely(anon_vma_prepare(vma))) |
697 | return VM_FAULT_OOM; | |
6d50e60c | 698 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 699 | return VM_FAULT_OOM; |
82b0f8c3 | 700 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 701 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
702 | transparent_hugepage_use_zero_page()) { |
703 | pgtable_t pgtable; | |
704 | struct page *zero_page; | |
705 | bool set; | |
2b740303 | 706 | vm_fault_t ret; |
4cf58924 | 707 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 708 | if (unlikely(!pgtable)) |
ba76149f | 709 | return VM_FAULT_OOM; |
6fcb52a5 | 710 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 711 | if (unlikely(!zero_page)) { |
bae473a4 | 712 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 713 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 714 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 715 | } |
82b0f8c3 | 716 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 AA |
717 | ret = 0; |
718 | set = false; | |
82b0f8c3 | 719 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
720 | ret = check_stable_address_space(vma->vm_mm); |
721 | if (ret) { | |
722 | spin_unlock(vmf->ptl); | |
723 | } else if (userfaultfd_missing(vma)) { | |
82b0f8c3 JK |
724 | spin_unlock(vmf->ptl); |
725 | ret = handle_userfault(vmf, VM_UFFD_MISSING); | |
6b251fc9 AA |
726 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
727 | } else { | |
bae473a4 | 728 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
729 | haddr, vmf->pmd, zero_page); |
730 | spin_unlock(vmf->ptl); | |
6b251fc9 AA |
731 | set = true; |
732 | } | |
733 | } else | |
82b0f8c3 | 734 | spin_unlock(vmf->ptl); |
6fcb52a5 | 735 | if (!set) |
bae473a4 | 736 | pte_free(vma->vm_mm, pgtable); |
6b251fc9 | 737 | return ret; |
71e3aac0 | 738 | } |
356ff8a9 DR |
739 | gfp = alloc_hugepage_direct_gfpmask(vma); |
740 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); | |
128ec037 KS |
741 | if (unlikely(!page)) { |
742 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 743 | return VM_FAULT_FALLBACK; |
128ec037 | 744 | } |
9a982250 | 745 | prep_transhuge_page(page); |
82b0f8c3 | 746 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
747 | } |
748 | ||
ae18d6dc | 749 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
750 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
751 | pgtable_t pgtable) | |
5cad465d MW |
752 | { |
753 | struct mm_struct *mm = vma->vm_mm; | |
754 | pmd_t entry; | |
755 | spinlock_t *ptl; | |
756 | ||
757 | ptl = pmd_lock(mm, pmd); | |
f25748e3 DW |
758 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
759 | if (pfn_t_devmap(pfn)) | |
760 | entry = pmd_mkdevmap(entry); | |
01871e59 | 761 | if (write) { |
f55e1014 LT |
762 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
763 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 764 | } |
3b6521f5 OH |
765 | |
766 | if (pgtable) { | |
767 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 768 | mm_inc_nr_ptes(mm); |
3b6521f5 OH |
769 | } |
770 | ||
01871e59 RZ |
771 | set_pmd_at(mm, addr, pmd, entry); |
772 | update_mmu_cache_pmd(vma, addr, pmd); | |
5cad465d | 773 | spin_unlock(ptl); |
5cad465d MW |
774 | } |
775 | ||
226ab561 | 776 | vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
f25748e3 | 777 | pmd_t *pmd, pfn_t pfn, bool write) |
5cad465d MW |
778 | { |
779 | pgprot_t pgprot = vma->vm_page_prot; | |
3b6521f5 | 780 | pgtable_t pgtable = NULL; |
5cad465d MW |
781 | /* |
782 | * If we had pmd_special, we could avoid all these restrictions, | |
783 | * but we need to be consistent with PTEs and architectures that | |
784 | * can't support a 'special' bit. | |
785 | */ | |
e1fb4a08 DJ |
786 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
787 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
788 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
789 | (VM_PFNMAP|VM_MIXEDMAP)); | |
790 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
791 | |
792 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
793 | return VM_FAULT_SIGBUS; | |
308a047c | 794 | |
3b6521f5 | 795 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 796 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
797 | if (!pgtable) |
798 | return VM_FAULT_OOM; | |
799 | } | |
800 | ||
308a047c BP |
801 | track_pfn_insert(vma, &pgprot, pfn); |
802 | ||
3b6521f5 | 803 | insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 804 | return VM_FAULT_NOPAGE; |
5cad465d | 805 | } |
dee41079 | 806 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 807 | |
a00cc7d9 | 808 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 809 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 810 | { |
f55e1014 | 811 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
812 | pud = pud_mkwrite(pud); |
813 | return pud; | |
814 | } | |
815 | ||
816 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
817 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
818 | { | |
819 | struct mm_struct *mm = vma->vm_mm; | |
820 | pud_t entry; | |
821 | spinlock_t *ptl; | |
822 | ||
823 | ptl = pud_lock(mm, pud); | |
824 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); | |
825 | if (pfn_t_devmap(pfn)) | |
826 | entry = pud_mkdevmap(entry); | |
827 | if (write) { | |
f55e1014 LT |
828 | entry = pud_mkyoung(pud_mkdirty(entry)); |
829 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
830 | } |
831 | set_pud_at(mm, addr, pud, entry); | |
832 | update_mmu_cache_pud(vma, addr, pud); | |
833 | spin_unlock(ptl); | |
834 | } | |
835 | ||
226ab561 | 836 | vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, |
a00cc7d9 MW |
837 | pud_t *pud, pfn_t pfn, bool write) |
838 | { | |
839 | pgprot_t pgprot = vma->vm_page_prot; | |
840 | /* | |
841 | * If we had pud_special, we could avoid all these restrictions, | |
842 | * but we need to be consistent with PTEs and architectures that | |
843 | * can't support a 'special' bit. | |
844 | */ | |
62ec0d8c DJ |
845 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
846 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
847 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
848 | (VM_PFNMAP|VM_MIXEDMAP)); | |
849 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
850 | |
851 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
852 | return VM_FAULT_SIGBUS; | |
853 | ||
854 | track_pfn_insert(vma, &pgprot, pfn); | |
855 | ||
856 | insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); | |
857 | return VM_FAULT_NOPAGE; | |
858 | } | |
859 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
860 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
861 | ||
3565fce3 | 862 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 863 | pmd_t *pmd, int flags) |
3565fce3 DW |
864 | { |
865 | pmd_t _pmd; | |
866 | ||
a8f97366 KS |
867 | _pmd = pmd_mkyoung(*pmd); |
868 | if (flags & FOLL_WRITE) | |
869 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 870 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 871 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
872 | update_mmu_cache_pmd(vma, addr, pmd); |
873 | } | |
874 | ||
875 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 876 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
877 | { |
878 | unsigned long pfn = pmd_pfn(*pmd); | |
879 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
880 | struct page *page; |
881 | ||
882 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
883 | ||
8310d48b KF |
884 | /* |
885 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
886 | * not be in this function with `flags & FOLL_COW` set. | |
887 | */ | |
888 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
889 | ||
f6f37321 | 890 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
891 | return NULL; |
892 | ||
893 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
894 | /* pass */; | |
895 | else | |
896 | return NULL; | |
897 | ||
898 | if (flags & FOLL_TOUCH) | |
a8f97366 | 899 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
900 | |
901 | /* | |
902 | * device mapped pages can only be returned if the | |
903 | * caller will manage the page reference count. | |
904 | */ | |
905 | if (!(flags & FOLL_GET)) | |
906 | return ERR_PTR(-EEXIST); | |
907 | ||
908 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
909 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
910 | if (!*pgmap) | |
3565fce3 DW |
911 | return ERR_PTR(-EFAULT); |
912 | page = pfn_to_page(pfn); | |
913 | get_page(page); | |
3565fce3 DW |
914 | |
915 | return page; | |
916 | } | |
917 | ||
71e3aac0 AA |
918 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
919 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
920 | struct vm_area_struct *vma) | |
921 | { | |
c4088ebd | 922 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
923 | struct page *src_page; |
924 | pmd_t pmd; | |
12c9d70b | 925 | pgtable_t pgtable = NULL; |
628d47ce | 926 | int ret = -ENOMEM; |
71e3aac0 | 927 | |
628d47ce KS |
928 | /* Skip if can be re-fill on fault */ |
929 | if (!vma_is_anonymous(vma)) | |
930 | return 0; | |
931 | ||
4cf58924 | 932 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
933 | if (unlikely(!pgtable)) |
934 | goto out; | |
71e3aac0 | 935 | |
c4088ebd KS |
936 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
937 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
938 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
939 | |
940 | ret = -EAGAIN; | |
941 | pmd = *src_pmd; | |
84c3fc4e ZY |
942 | |
943 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
944 | if (unlikely(is_swap_pmd(pmd))) { | |
945 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
946 | ||
947 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
948 | if (is_write_migration_entry(entry)) { | |
949 | make_migration_entry_read(&entry); | |
950 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
951 | if (pmd_swp_soft_dirty(*src_pmd)) |
952 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
953 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
954 | } | |
dd8a67f9 | 955 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 956 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 957 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
958 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
959 | ret = 0; | |
960 | goto out_unlock; | |
961 | } | |
962 | #endif | |
963 | ||
628d47ce | 964 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
965 | pte_free(dst_mm, pgtable); |
966 | goto out_unlock; | |
967 | } | |
fc9fe822 | 968 | /* |
c4088ebd | 969 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
970 | * under splitting since we don't split the page itself, only pmd to |
971 | * a page table. | |
972 | */ | |
973 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 974 | struct page *zero_page; |
97ae1749 KS |
975 | /* |
976 | * get_huge_zero_page() will never allocate a new page here, | |
977 | * since we already have a zero page to copy. It just takes a | |
978 | * reference. | |
979 | */ | |
6fcb52a5 | 980 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 981 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 982 | zero_page); |
fc9fe822 KS |
983 | ret = 0; |
984 | goto out_unlock; | |
985 | } | |
de466bd6 | 986 | |
628d47ce KS |
987 | src_page = pmd_page(pmd); |
988 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
989 | get_page(src_page); | |
990 | page_dup_rmap(src_page, true); | |
991 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 992 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 993 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
994 | |
995 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
996 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
997 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
998 | |
999 | ret = 0; | |
1000 | out_unlock: | |
c4088ebd KS |
1001 | spin_unlock(src_ptl); |
1002 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1003 | out: |
1004 | return ret; | |
1005 | } | |
1006 | ||
a00cc7d9 MW |
1007 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1008 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1009 | pud_t *pud, int flags) |
a00cc7d9 MW |
1010 | { |
1011 | pud_t _pud; | |
1012 | ||
a8f97366 KS |
1013 | _pud = pud_mkyoung(*pud); |
1014 | if (flags & FOLL_WRITE) | |
1015 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1016 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1017 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1018 | update_mmu_cache_pud(vma, addr, pud); |
1019 | } | |
1020 | ||
1021 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1022 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1023 | { |
1024 | unsigned long pfn = pud_pfn(*pud); | |
1025 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1026 | struct page *page; |
1027 | ||
1028 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1029 | ||
f6f37321 | 1030 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1031 | return NULL; |
1032 | ||
1033 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1034 | /* pass */; | |
1035 | else | |
1036 | return NULL; | |
1037 | ||
1038 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1039 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1040 | |
1041 | /* | |
1042 | * device mapped pages can only be returned if the | |
1043 | * caller will manage the page reference count. | |
1044 | */ | |
1045 | if (!(flags & FOLL_GET)) | |
1046 | return ERR_PTR(-EEXIST); | |
1047 | ||
1048 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1049 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1050 | if (!*pgmap) | |
a00cc7d9 MW |
1051 | return ERR_PTR(-EFAULT); |
1052 | page = pfn_to_page(pfn); | |
1053 | get_page(page); | |
a00cc7d9 MW |
1054 | |
1055 | return page; | |
1056 | } | |
1057 | ||
1058 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1059 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1060 | struct vm_area_struct *vma) | |
1061 | { | |
1062 | spinlock_t *dst_ptl, *src_ptl; | |
1063 | pud_t pud; | |
1064 | int ret; | |
1065 | ||
1066 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1067 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1068 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1069 | ||
1070 | ret = -EAGAIN; | |
1071 | pud = *src_pud; | |
1072 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1073 | goto out_unlock; | |
1074 | ||
1075 | /* | |
1076 | * When page table lock is held, the huge zero pud should not be | |
1077 | * under splitting since we don't split the page itself, only pud to | |
1078 | * a page table. | |
1079 | */ | |
1080 | if (is_huge_zero_pud(pud)) { | |
1081 | /* No huge zero pud yet */ | |
1082 | } | |
1083 | ||
1084 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1085 | pud = pud_mkold(pud_wrprotect(pud)); | |
1086 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1087 | ||
1088 | ret = 0; | |
1089 | out_unlock: | |
1090 | spin_unlock(src_ptl); | |
1091 | spin_unlock(dst_ptl); | |
1092 | return ret; | |
1093 | } | |
1094 | ||
1095 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1096 | { | |
1097 | pud_t entry; | |
1098 | unsigned long haddr; | |
1099 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1100 | ||
1101 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1102 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1103 | goto unlock; | |
1104 | ||
1105 | entry = pud_mkyoung(orig_pud); | |
1106 | if (write) | |
1107 | entry = pud_mkdirty(entry); | |
1108 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1109 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1110 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1111 | ||
1112 | unlock: | |
1113 | spin_unlock(vmf->ptl); | |
1114 | } | |
1115 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1116 | ||
82b0f8c3 | 1117 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1118 | { |
1119 | pmd_t entry; | |
1120 | unsigned long haddr; | |
20f664aa | 1121 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1122 | |
82b0f8c3 JK |
1123 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1124 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1125 | goto unlock; |
1126 | ||
1127 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1128 | if (write) |
1129 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1130 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1131 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1132 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1133 | |
1134 | unlock: | |
82b0f8c3 | 1135 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1136 | } |
1137 | ||
2b740303 SJ |
1138 | static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, |
1139 | pmd_t orig_pmd, struct page *page) | |
71e3aac0 | 1140 | { |
82b0f8c3 JK |
1141 | struct vm_area_struct *vma = vmf->vma; |
1142 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1143 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1144 | pgtable_t pgtable; |
1145 | pmd_t _pmd; | |
2b740303 SJ |
1146 | int i; |
1147 | vm_fault_t ret = 0; | |
71e3aac0 | 1148 | struct page **pages; |
ac46d4f3 | 1149 | struct mmu_notifier_range range; |
71e3aac0 | 1150 | |
6da2ec56 KC |
1151 | pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), |
1152 | GFP_KERNEL); | |
71e3aac0 AA |
1153 | if (unlikely(!pages)) { |
1154 | ret |= VM_FAULT_OOM; | |
1155 | goto out; | |
1156 | } | |
1157 | ||
1158 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1159 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1160 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1161 | if (unlikely(!pages[i] || |
2cf85583 | 1162 | mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, |
bae473a4 | 1163 | GFP_KERNEL, &memcg, false))) { |
b9bbfbe3 | 1164 | if (pages[i]) |
71e3aac0 | 1165 | put_page(pages[i]); |
b9bbfbe3 | 1166 | while (--i >= 0) { |
00501b53 JW |
1167 | memcg = (void *)page_private(pages[i]); |
1168 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1169 | mem_cgroup_cancel_charge(pages[i], memcg, |
1170 | false); | |
b9bbfbe3 AA |
1171 | put_page(pages[i]); |
1172 | } | |
71e3aac0 AA |
1173 | kfree(pages); |
1174 | ret |= VM_FAULT_OOM; | |
1175 | goto out; | |
1176 | } | |
00501b53 | 1177 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1178 | } |
1179 | ||
1180 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1181 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1182 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1183 | __SetPageUptodate(pages[i]); |
1184 | cond_resched(); | |
1185 | } | |
1186 | ||
ac46d4f3 JG |
1187 | mmu_notifier_range_init(&range, vma->vm_mm, haddr, |
1188 | haddr + HPAGE_PMD_SIZE); | |
1189 | mmu_notifier_invalidate_range_start(&range); | |
2ec74c3e | 1190 | |
82b0f8c3 JK |
1191 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1192 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1193 | goto out_free_pages; |
309381fe | 1194 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1195 | |
0f10851e JG |
1196 | /* |
1197 | * Leave pmd empty until pte is filled note we must notify here as | |
1198 | * concurrent CPU thread might write to new page before the call to | |
1199 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1200 | * device seeing memory write in different order than CPU. | |
1201 | * | |
ad56b738 | 1202 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 1203 | */ |
82b0f8c3 | 1204 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1205 | |
82b0f8c3 | 1206 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1207 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1208 | |
1209 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1210 | pte_t entry; |
71e3aac0 AA |
1211 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1212 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1213 | memcg = (void *)page_private(pages[i]); |
1214 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1215 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1216 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1217 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1218 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1219 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1220 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1221 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1222 | } |
1223 | kfree(pages); | |
1224 | ||
71e3aac0 | 1225 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1226 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1227 | page_remove_rmap(page, true); |
82b0f8c3 | 1228 | spin_unlock(vmf->ptl); |
71e3aac0 | 1229 | |
4645b9fe JG |
1230 | /* |
1231 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1232 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1233 | */ | |
ac46d4f3 | 1234 | mmu_notifier_invalidate_range_only_end(&range); |
2ec74c3e | 1235 | |
71e3aac0 AA |
1236 | ret |= VM_FAULT_WRITE; |
1237 | put_page(page); | |
1238 | ||
1239 | out: | |
1240 | return ret; | |
1241 | ||
1242 | out_free_pages: | |
82b0f8c3 | 1243 | spin_unlock(vmf->ptl); |
ac46d4f3 | 1244 | mmu_notifier_invalidate_range_end(&range); |
b9bbfbe3 | 1245 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1246 | memcg = (void *)page_private(pages[i]); |
1247 | set_page_private(pages[i], 0); | |
f627c2f5 | 1248 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1249 | put_page(pages[i]); |
b9bbfbe3 | 1250 | } |
71e3aac0 AA |
1251 | kfree(pages); |
1252 | goto out; | |
1253 | } | |
1254 | ||
2b740303 | 1255 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1256 | { |
82b0f8c3 | 1257 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1258 | struct page *page = NULL, *new_page; |
00501b53 | 1259 | struct mem_cgroup *memcg; |
82b0f8c3 | 1260 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
ac46d4f3 | 1261 | struct mmu_notifier_range range; |
3b363692 | 1262 | gfp_t huge_gfp; /* for allocation and charge */ |
2b740303 | 1263 | vm_fault_t ret = 0; |
71e3aac0 | 1264 | |
82b0f8c3 | 1265 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1266 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1267 | if (is_huge_zero_pmd(orig_pmd)) |
1268 | goto alloc; | |
82b0f8c3 JK |
1269 | spin_lock(vmf->ptl); |
1270 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1271 | goto out_unlock; |
1272 | ||
1273 | page = pmd_page(orig_pmd); | |
309381fe | 1274 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1275 | /* |
1276 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1277 | * part. |
1f25fe20 | 1278 | */ |
ba3c4ce6 HY |
1279 | if (!trylock_page(page)) { |
1280 | get_page(page); | |
1281 | spin_unlock(vmf->ptl); | |
1282 | lock_page(page); | |
1283 | spin_lock(vmf->ptl); | |
1284 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1285 | unlock_page(page); | |
1286 | put_page(page); | |
1287 | goto out_unlock; | |
1288 | } | |
1289 | put_page(page); | |
1290 | } | |
1291 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1292 | pmd_t entry; |
1293 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1294 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1295 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1296 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1297 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1298 | unlock_page(page); |
71e3aac0 AA |
1299 | goto out_unlock; |
1300 | } | |
ba3c4ce6 | 1301 | unlock_page(page); |
ddc58f27 | 1302 | get_page(page); |
82b0f8c3 | 1303 | spin_unlock(vmf->ptl); |
93b4796d | 1304 | alloc: |
7635d9cb | 1305 | if (__transparent_hugepage_enabled(vma) && |
077fcf11 | 1306 | !transparent_hugepage_debug_cow()) { |
356ff8a9 DR |
1307 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
1308 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); | |
077fcf11 | 1309 | } else |
71e3aac0 AA |
1310 | new_page = NULL; |
1311 | ||
9a982250 KS |
1312 | if (likely(new_page)) { |
1313 | prep_transhuge_page(new_page); | |
1314 | } else { | |
eecc1e42 | 1315 | if (!page) { |
82b0f8c3 | 1316 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1317 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1318 | } else { |
82b0f8c3 | 1319 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1320 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1321 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1322 | ret |= VM_FAULT_FALLBACK; |
1323 | } | |
ddc58f27 | 1324 | put_page(page); |
93b4796d | 1325 | } |
17766dde | 1326 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1327 | goto out; |
1328 | } | |
1329 | ||
2cf85583 | 1330 | if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, |
2a70f6a7 | 1331 | huge_gfp, &memcg, true))) { |
b9bbfbe3 | 1332 | put_page(new_page); |
82b0f8c3 | 1333 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1334 | if (page) |
ddc58f27 | 1335 | put_page(page); |
9845cbbd | 1336 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1337 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1338 | goto out; |
1339 | } | |
1340 | ||
17766dde | 1341 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 1342 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
17766dde | 1343 | |
eecc1e42 | 1344 | if (!page) |
c79b57e4 | 1345 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d | 1346 | else |
c9f4cd71 HY |
1347 | copy_user_huge_page(new_page, page, vmf->address, |
1348 | vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1349 | __SetPageUptodate(new_page); |
1350 | ||
ac46d4f3 JG |
1351 | mmu_notifier_range_init(&range, vma->vm_mm, haddr, |
1352 | haddr + HPAGE_PMD_SIZE); | |
1353 | mmu_notifier_invalidate_range_start(&range); | |
2ec74c3e | 1354 | |
82b0f8c3 | 1355 | spin_lock(vmf->ptl); |
93b4796d | 1356 | if (page) |
ddc58f27 | 1357 | put_page(page); |
82b0f8c3 JK |
1358 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1359 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1360 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1361 | put_page(new_page); |
2ec74c3e | 1362 | goto out_mn; |
b9bbfbe3 | 1363 | } else { |
71e3aac0 | 1364 | pmd_t entry; |
3122359a | 1365 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
f55e1014 | 1366 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 | 1367 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1368 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1369 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1370 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1371 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1372 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1373 | if (!page) { |
bae473a4 | 1374 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1375 | } else { |
309381fe | 1376 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1377 | page_remove_rmap(page, true); |
93b4796d KS |
1378 | put_page(page); |
1379 | } | |
71e3aac0 AA |
1380 | ret |= VM_FAULT_WRITE; |
1381 | } | |
82b0f8c3 | 1382 | spin_unlock(vmf->ptl); |
2ec74c3e | 1383 | out_mn: |
4645b9fe JG |
1384 | /* |
1385 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1386 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1387 | */ | |
ac46d4f3 | 1388 | mmu_notifier_invalidate_range_only_end(&range); |
71e3aac0 AA |
1389 | out: |
1390 | return ret; | |
2ec74c3e | 1391 | out_unlock: |
82b0f8c3 | 1392 | spin_unlock(vmf->ptl); |
2ec74c3e | 1393 | return ret; |
71e3aac0 AA |
1394 | } |
1395 | ||
8310d48b KF |
1396 | /* |
1397 | * FOLL_FORCE can write to even unwritable pmd's, but only | |
1398 | * after we've gone through a COW cycle and they are dirty. | |
1399 | */ | |
1400 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1401 | { | |
f6f37321 | 1402 | return pmd_write(pmd) || |
8310d48b KF |
1403 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); |
1404 | } | |
1405 | ||
b676b293 | 1406 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1407 | unsigned long addr, |
1408 | pmd_t *pmd, | |
1409 | unsigned int flags) | |
1410 | { | |
b676b293 | 1411 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1412 | struct page *page = NULL; |
1413 | ||
c4088ebd | 1414 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1415 | |
8310d48b | 1416 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1417 | goto out; |
1418 | ||
85facf25 KS |
1419 | /* Avoid dumping huge zero page */ |
1420 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1421 | return ERR_PTR(-EFAULT); | |
1422 | ||
2b4847e7 | 1423 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1424 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1425 | goto out; |
1426 | ||
71e3aac0 | 1427 | page = pmd_page(*pmd); |
ca120cf6 | 1428 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1429 | if (flags & FOLL_TOUCH) |
a8f97366 | 1430 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1431 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1432 | /* |
1433 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1434 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1435 | * | |
9a73f61b KS |
1436 | * For anon THP: |
1437 | * | |
e90309c9 KS |
1438 | * In most cases the pmd is the only mapping of the page as we |
1439 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1440 | * writable private mappings in populate_vma_page_range(). | |
1441 | * | |
1442 | * The only scenario when we have the page shared here is if we | |
1443 | * mlocking read-only mapping shared over fork(). We skip | |
1444 | * mlocking such pages. | |
9a73f61b KS |
1445 | * |
1446 | * For file THP: | |
1447 | * | |
1448 | * We can expect PageDoubleMap() to be stable under page lock: | |
1449 | * for file pages we set it in page_add_file_rmap(), which | |
1450 | * requires page to be locked. | |
e90309c9 | 1451 | */ |
9a73f61b KS |
1452 | |
1453 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1454 | goto skip_mlock; | |
1455 | if (PageDoubleMap(page) || !page->mapping) | |
1456 | goto skip_mlock; | |
1457 | if (!trylock_page(page)) | |
1458 | goto skip_mlock; | |
1459 | lru_add_drain(); | |
1460 | if (page->mapping && !PageDoubleMap(page)) | |
1461 | mlock_vma_page(page); | |
1462 | unlock_page(page); | |
b676b293 | 1463 | } |
9a73f61b | 1464 | skip_mlock: |
71e3aac0 | 1465 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1466 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1467 | if (flags & FOLL_GET) |
ddc58f27 | 1468 | get_page(page); |
71e3aac0 AA |
1469 | |
1470 | out: | |
1471 | return page; | |
1472 | } | |
1473 | ||
d10e63f2 | 1474 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1475 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1476 | { |
82b0f8c3 | 1477 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1478 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1479 | struct page *page; |
82b0f8c3 | 1480 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1481 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1482 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1483 | bool page_locked; |
1484 | bool migrated = false; | |
b191f9b1 | 1485 | bool was_writable; |
6688cc05 | 1486 | int flags = 0; |
d10e63f2 | 1487 | |
82b0f8c3 JK |
1488 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1489 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1490 | goto out_unlock; |
1491 | ||
de466bd6 MG |
1492 | /* |
1493 | * If there are potential migrations, wait for completion and retry | |
1494 | * without disrupting NUMA hinting information. Do not relock and | |
1495 | * check_same as the page may no longer be mapped. | |
1496 | */ | |
82b0f8c3 JK |
1497 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1498 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1499 | if (!get_page_unless_zero(page)) |
1500 | goto out_unlock; | |
82b0f8c3 | 1501 | spin_unlock(vmf->ptl); |
9a1ea439 | 1502 | put_and_wait_on_page_locked(page); |
de466bd6 MG |
1503 | goto out; |
1504 | } | |
1505 | ||
d10e63f2 | 1506 | page = pmd_page(pmd); |
a1a46184 | 1507 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1508 | page_nid = page_to_nid(page); |
90572890 | 1509 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1510 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1511 | if (page_nid == this_nid) { |
03c5a6e1 | 1512 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1513 | flags |= TNF_FAULT_LOCAL; |
1514 | } | |
4daae3b4 | 1515 | |
bea66fbd | 1516 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1517 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1518 | flags |= TNF_NO_GROUP; |
1519 | ||
ff9042b1 MG |
1520 | /* |
1521 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1522 | * page_table_lock if at all possible | |
1523 | */ | |
b8916634 MG |
1524 | page_locked = trylock_page(page); |
1525 | target_nid = mpol_misplaced(page, vma, haddr); | |
98fa15f3 | 1526 | if (target_nid == NUMA_NO_NODE) { |
b8916634 | 1527 | /* If the page was locked, there are no parallel migrations */ |
a54a407f | 1528 | if (page_locked) |
b8916634 | 1529 | goto clear_pmdnuma; |
2b4847e7 | 1530 | } |
4daae3b4 | 1531 | |
de466bd6 | 1532 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1533 | if (!page_locked) { |
98fa15f3 | 1534 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1535 | if (!get_page_unless_zero(page)) |
1536 | goto out_unlock; | |
82b0f8c3 | 1537 | spin_unlock(vmf->ptl); |
9a1ea439 | 1538 | put_and_wait_on_page_locked(page); |
b8916634 MG |
1539 | goto out; |
1540 | } | |
1541 | ||
2b4847e7 MG |
1542 | /* |
1543 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1544 | * to serialises splits | |
1545 | */ | |
b8916634 | 1546 | get_page(page); |
82b0f8c3 | 1547 | spin_unlock(vmf->ptl); |
b8916634 | 1548 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1549 | |
c69307d5 | 1550 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1551 | spin_lock(vmf->ptl); |
1552 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1553 | unlock_page(page); |
1554 | put_page(page); | |
98fa15f3 | 1555 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1556 | goto out_unlock; |
b32967ff | 1557 | } |
ff9042b1 | 1558 | |
c3a489ca MG |
1559 | /* Bail if we fail to protect against THP splits for any reason */ |
1560 | if (unlikely(!anon_vma)) { | |
1561 | put_page(page); | |
98fa15f3 | 1562 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1563 | goto clear_pmdnuma; |
1564 | } | |
1565 | ||
8b1b436d PZ |
1566 | /* |
1567 | * Since we took the NUMA fault, we must have observed the !accessible | |
1568 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1569 | * modifying the page we're about to migrate. | |
1570 | * | |
1571 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1572 | * inc_tlb_flush_pending(). |
1573 | * | |
1574 | * We are not sure a pending tlb flush here is for a huge page | |
1575 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1576 | */ |
7066f0f9 | 1577 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1578 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1579 | /* |
1580 | * change_huge_pmd() released the pmd lock before | |
1581 | * invalidating the secondary MMUs sharing the primary | |
1582 | * MMU pagetables (with ->invalidate_range()). The | |
1583 | * mmu_notifier_invalidate_range_end() (which | |
1584 | * internally calls ->invalidate_range()) in | |
1585 | * change_pmd_range() will run after us, so we can't | |
1586 | * rely on it here and we need an explicit invalidate. | |
1587 | */ | |
1588 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1589 | haddr + HPAGE_PMD_SIZE); | |
1590 | } | |
8b1b436d | 1591 | |
a54a407f MG |
1592 | /* |
1593 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1594 | * and access rights restored. |
a54a407f | 1595 | */ |
82b0f8c3 | 1596 | spin_unlock(vmf->ptl); |
8b1b436d | 1597 | |
bae473a4 | 1598 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1599 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1600 | if (migrated) { |
1601 | flags |= TNF_MIGRATED; | |
8191acbd | 1602 | page_nid = target_nid; |
074c2381 MG |
1603 | } else |
1604 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1605 | |
8191acbd | 1606 | goto out; |
b32967ff | 1607 | clear_pmdnuma: |
a54a407f | 1608 | BUG_ON(!PageLocked(page)); |
288bc549 | 1609 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1610 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1611 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1612 | if (was_writable) |
1613 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1614 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1615 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1616 | unlock_page(page); |
d10e63f2 | 1617 | out_unlock: |
82b0f8c3 | 1618 | spin_unlock(vmf->ptl); |
b8916634 MG |
1619 | |
1620 | out: | |
1621 | if (anon_vma) | |
1622 | page_unlock_anon_vma_read(anon_vma); | |
1623 | ||
98fa15f3 | 1624 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1625 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1626 | flags); |
8191acbd | 1627 | |
d10e63f2 MG |
1628 | return 0; |
1629 | } | |
1630 | ||
319904ad HY |
1631 | /* |
1632 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1633 | * Otherwise, return false. | |
1634 | */ | |
1635 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1636 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1637 | { |
1638 | spinlock_t *ptl; | |
1639 | pmd_t orig_pmd; | |
1640 | struct page *page; | |
1641 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1642 | bool ret = false; |
b8d3c4c3 | 1643 | |
07e32661 AK |
1644 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1645 | ||
b6ec57f4 KS |
1646 | ptl = pmd_trans_huge_lock(pmd, vma); |
1647 | if (!ptl) | |
25eedabe | 1648 | goto out_unlocked; |
b8d3c4c3 MK |
1649 | |
1650 | orig_pmd = *pmd; | |
319904ad | 1651 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1652 | goto out; |
b8d3c4c3 | 1653 | |
84c3fc4e ZY |
1654 | if (unlikely(!pmd_present(orig_pmd))) { |
1655 | VM_BUG_ON(thp_migration_supported() && | |
1656 | !is_pmd_migration_entry(orig_pmd)); | |
1657 | goto out; | |
1658 | } | |
1659 | ||
b8d3c4c3 MK |
1660 | page = pmd_page(orig_pmd); |
1661 | /* | |
1662 | * If other processes are mapping this page, we couldn't discard | |
1663 | * the page unless they all do MADV_FREE so let's skip the page. | |
1664 | */ | |
1665 | if (page_mapcount(page) != 1) | |
1666 | goto out; | |
1667 | ||
1668 | if (!trylock_page(page)) | |
1669 | goto out; | |
1670 | ||
1671 | /* | |
1672 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1673 | * will deactivate only them. | |
1674 | */ | |
1675 | if (next - addr != HPAGE_PMD_SIZE) { | |
1676 | get_page(page); | |
1677 | spin_unlock(ptl); | |
9818b8cd | 1678 | split_huge_page(page); |
b8d3c4c3 | 1679 | unlock_page(page); |
bbf29ffc | 1680 | put_page(page); |
b8d3c4c3 MK |
1681 | goto out_unlocked; |
1682 | } | |
1683 | ||
1684 | if (PageDirty(page)) | |
1685 | ClearPageDirty(page); | |
1686 | unlock_page(page); | |
1687 | ||
b8d3c4c3 | 1688 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1689 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1690 | orig_pmd = pmd_mkold(orig_pmd); |
1691 | orig_pmd = pmd_mkclean(orig_pmd); | |
1692 | ||
1693 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1694 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1695 | } | |
802a3a92 SL |
1696 | |
1697 | mark_page_lazyfree(page); | |
319904ad | 1698 | ret = true; |
b8d3c4c3 MK |
1699 | out: |
1700 | spin_unlock(ptl); | |
1701 | out_unlocked: | |
1702 | return ret; | |
1703 | } | |
1704 | ||
953c66c2 AK |
1705 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1706 | { | |
1707 | pgtable_t pgtable; | |
1708 | ||
1709 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1710 | pte_free(mm, pgtable); | |
c4812909 | 1711 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1712 | } |
1713 | ||
71e3aac0 | 1714 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1715 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1716 | { |
da146769 | 1717 | pmd_t orig_pmd; |
bf929152 | 1718 | spinlock_t *ptl; |
71e3aac0 | 1719 | |
07e32661 AK |
1720 | tlb_remove_check_page_size_change(tlb, HPAGE_PMD_SIZE); |
1721 | ||
b6ec57f4 KS |
1722 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1723 | if (!ptl) | |
da146769 KS |
1724 | return 0; |
1725 | /* | |
1726 | * For architectures like ppc64 we look at deposited pgtable | |
1727 | * when calling pmdp_huge_get_and_clear. So do the | |
1728 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1729 | * operations. | |
1730 | */ | |
1731 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1732 | tlb->fullmm); | |
1733 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1734 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1735 | if (arch_needs_pgtable_deposit()) |
1736 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1737 | spin_unlock(ptl); |
1738 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1739 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1740 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1741 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1742 | spin_unlock(ptl); |
c0f2e176 | 1743 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1744 | } else { |
616b8371 ZY |
1745 | struct page *page = NULL; |
1746 | int flush_needed = 1; | |
1747 | ||
1748 | if (pmd_present(orig_pmd)) { | |
1749 | page = pmd_page(orig_pmd); | |
1750 | page_remove_rmap(page, true); | |
1751 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1752 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1753 | } else if (thp_migration_supported()) { | |
1754 | swp_entry_t entry; | |
1755 | ||
1756 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1757 | entry = pmd_to_swp_entry(orig_pmd); | |
1758 | page = pfn_to_page(swp_offset(entry)); | |
1759 | flush_needed = 0; | |
1760 | } else | |
1761 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1762 | ||
b5072380 | 1763 | if (PageAnon(page)) { |
c14a6eb4 | 1764 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1765 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1766 | } else { | |
953c66c2 AK |
1767 | if (arch_needs_pgtable_deposit()) |
1768 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1769 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1770 | } |
616b8371 | 1771 | |
da146769 | 1772 | spin_unlock(ptl); |
616b8371 ZY |
1773 | if (flush_needed) |
1774 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1775 | } |
da146769 | 1776 | return 1; |
71e3aac0 AA |
1777 | } |
1778 | ||
1dd38b6c AK |
1779 | #ifndef pmd_move_must_withdraw |
1780 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1781 | spinlock_t *old_pmd_ptl, | |
1782 | struct vm_area_struct *vma) | |
1783 | { | |
1784 | /* | |
1785 | * With split pmd lock we also need to move preallocated | |
1786 | * PTE page table if new_pmd is on different PMD page table. | |
1787 | * | |
1788 | * We also don't deposit and withdraw tables for file pages. | |
1789 | */ | |
1790 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1791 | } | |
1792 | #endif | |
1793 | ||
ab6e3d09 NH |
1794 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1795 | { | |
1796 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1797 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1798 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1799 | else if (pmd_present(pmd)) | |
1800 | pmd = pmd_mksoft_dirty(pmd); | |
1801 | #endif | |
1802 | return pmd; | |
1803 | } | |
1804 | ||
bf8616d5 | 1805 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1806 | unsigned long new_addr, unsigned long old_end, |
eb66ae03 | 1807 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1808 | { |
bf929152 | 1809 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1810 | pmd_t pmd; |
37a1c49a | 1811 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1812 | bool force_flush = false; |
37a1c49a AA |
1813 | |
1814 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1815 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1816 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1817 | return false; |
37a1c49a AA |
1818 | |
1819 | /* | |
1820 | * The destination pmd shouldn't be established, free_pgtables() | |
1821 | * should have release it. | |
1822 | */ | |
1823 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1824 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1825 | return false; |
37a1c49a AA |
1826 | } |
1827 | ||
bf929152 KS |
1828 | /* |
1829 | * We don't have to worry about the ordering of src and dst | |
1830 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1831 | */ | |
b6ec57f4 KS |
1832 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1833 | if (old_ptl) { | |
bf929152 KS |
1834 | new_ptl = pmd_lockptr(mm, new_pmd); |
1835 | if (new_ptl != old_ptl) | |
1836 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1837 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1838 | if (pmd_present(pmd)) |
a2ce2666 | 1839 | force_flush = true; |
025c5b24 | 1840 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1841 | |
1dd38b6c | 1842 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1843 | pgtable_t pgtable; |
3592806c KS |
1844 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1845 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1846 | } |
ab6e3d09 NH |
1847 | pmd = move_soft_dirty_pmd(pmd); |
1848 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1849 | if (force_flush) |
1850 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1851 | if (new_ptl != old_ptl) |
1852 | spin_unlock(new_ptl); | |
bf929152 | 1853 | spin_unlock(old_ptl); |
4b471e88 | 1854 | return true; |
37a1c49a | 1855 | } |
4b471e88 | 1856 | return false; |
37a1c49a AA |
1857 | } |
1858 | ||
f123d74a MG |
1859 | /* |
1860 | * Returns | |
1861 | * - 0 if PMD could not be locked | |
1862 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1863 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1864 | */ | |
cd7548ab | 1865 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1866 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1867 | { |
1868 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1869 | spinlock_t *ptl; |
0a85e51d KS |
1870 | pmd_t entry; |
1871 | bool preserve_write; | |
1872 | int ret; | |
cd7548ab | 1873 | |
b6ec57f4 | 1874 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1875 | if (!ptl) |
1876 | return 0; | |
e944fd67 | 1877 | |
0a85e51d KS |
1878 | preserve_write = prot_numa && pmd_write(*pmd); |
1879 | ret = 1; | |
e944fd67 | 1880 | |
84c3fc4e ZY |
1881 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1882 | if (is_swap_pmd(*pmd)) { | |
1883 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1884 | ||
1885 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1886 | if (is_write_migration_entry(entry)) { | |
1887 | pmd_t newpmd; | |
1888 | /* | |
1889 | * A protection check is difficult so | |
1890 | * just be safe and disable write | |
1891 | */ | |
1892 | make_migration_entry_read(&entry); | |
1893 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1894 | if (pmd_swp_soft_dirty(*pmd)) |
1895 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1896 | set_pmd_at(mm, addr, pmd, newpmd); |
1897 | } | |
1898 | goto unlock; | |
1899 | } | |
1900 | #endif | |
1901 | ||
0a85e51d KS |
1902 | /* |
1903 | * Avoid trapping faults against the zero page. The read-only | |
1904 | * data is likely to be read-cached on the local CPU and | |
1905 | * local/remote hits to the zero page are not interesting. | |
1906 | */ | |
1907 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1908 | goto unlock; | |
025c5b24 | 1909 | |
0a85e51d KS |
1910 | if (prot_numa && pmd_protnone(*pmd)) |
1911 | goto unlock; | |
1912 | ||
ced10803 KS |
1913 | /* |
1914 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1915 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1916 | * which is also under down_read(mmap_sem): | |
1917 | * | |
1918 | * CPU0: CPU1: | |
1919 | * change_huge_pmd(prot_numa=1) | |
1920 | * pmdp_huge_get_and_clear_notify() | |
1921 | * madvise_dontneed() | |
1922 | * zap_pmd_range() | |
1923 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1924 | * // skip the pmd | |
1925 | * set_pmd_at(); | |
1926 | * // pmd is re-established | |
1927 | * | |
1928 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1929 | * which may break userspace. | |
1930 | * | |
1931 | * pmdp_invalidate() is required to make sure we don't miss | |
1932 | * dirty/young flags set by hardware. | |
1933 | */ | |
a3cf988f | 1934 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1935 | |
0a85e51d KS |
1936 | entry = pmd_modify(entry, newprot); |
1937 | if (preserve_write) | |
1938 | entry = pmd_mk_savedwrite(entry); | |
1939 | ret = HPAGE_PMD_NR; | |
1940 | set_pmd_at(mm, addr, pmd, entry); | |
1941 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1942 | unlock: | |
1943 | spin_unlock(ptl); | |
025c5b24 NH |
1944 | return ret; |
1945 | } | |
1946 | ||
1947 | /* | |
8f19b0c0 | 1948 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1949 | * |
8f19b0c0 HY |
1950 | * Note that if it returns page table lock pointer, this routine returns without |
1951 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1952 | */ |
b6ec57f4 | 1953 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1954 | { |
b6ec57f4 KS |
1955 | spinlock_t *ptl; |
1956 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1957 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1958 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1959 | return ptl; |
1960 | spin_unlock(ptl); | |
1961 | return NULL; | |
cd7548ab JW |
1962 | } |
1963 | ||
a00cc7d9 MW |
1964 | /* |
1965 | * Returns true if a given pud maps a thp, false otherwise. | |
1966 | * | |
1967 | * Note that if it returns true, this routine returns without unlocking page | |
1968 | * table lock. So callers must unlock it. | |
1969 | */ | |
1970 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1971 | { | |
1972 | spinlock_t *ptl; | |
1973 | ||
1974 | ptl = pud_lock(vma->vm_mm, pud); | |
1975 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1976 | return ptl; | |
1977 | spin_unlock(ptl); | |
1978 | return NULL; | |
1979 | } | |
1980 | ||
1981 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1982 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1983 | pud_t *pud, unsigned long addr) | |
1984 | { | |
1985 | pud_t orig_pud; | |
1986 | spinlock_t *ptl; | |
1987 | ||
1988 | ptl = __pud_trans_huge_lock(pud, vma); | |
1989 | if (!ptl) | |
1990 | return 0; | |
1991 | /* | |
1992 | * For architectures like ppc64 we look at deposited pgtable | |
1993 | * when calling pudp_huge_get_and_clear. So do the | |
1994 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1995 | * operations. | |
1996 | */ | |
1997 | orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, | |
1998 | tlb->fullmm); | |
1999 | tlb_remove_pud_tlb_entry(tlb, pud, addr); | |
2000 | if (vma_is_dax(vma)) { | |
2001 | spin_unlock(ptl); | |
2002 | /* No zero page support yet */ | |
2003 | } else { | |
2004 | /* No support for anonymous PUD pages yet */ | |
2005 | BUG(); | |
2006 | } | |
2007 | return 1; | |
2008 | } | |
2009 | ||
2010 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2011 | unsigned long haddr) | |
2012 | { | |
2013 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2014 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2015 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2016 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2017 | ||
ce9311cf | 2018 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2019 | |
2020 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2021 | } | |
2022 | ||
2023 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2024 | unsigned long address) | |
2025 | { | |
2026 | spinlock_t *ptl; | |
ac46d4f3 | 2027 | struct mmu_notifier_range range; |
a00cc7d9 | 2028 | |
ac46d4f3 JG |
2029 | mmu_notifier_range_init(&range, vma->vm_mm, address & HPAGE_PUD_MASK, |
2030 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); | |
2031 | mmu_notifier_invalidate_range_start(&range); | |
2032 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2033 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2034 | goto out; | |
ac46d4f3 | 2035 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2036 | |
2037 | out: | |
2038 | spin_unlock(ptl); | |
4645b9fe JG |
2039 | /* |
2040 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2041 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2042 | */ | |
ac46d4f3 | 2043 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2044 | } |
2045 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2046 | ||
eef1b3ba KS |
2047 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2048 | unsigned long haddr, pmd_t *pmd) | |
2049 | { | |
2050 | struct mm_struct *mm = vma->vm_mm; | |
2051 | pgtable_t pgtable; | |
2052 | pmd_t _pmd; | |
2053 | int i; | |
2054 | ||
0f10851e JG |
2055 | /* |
2056 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2057 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2058 | * replacing a zero pmd write protected page with a zero pte write | |
2059 | * protected page. | |
2060 | * | |
ad56b738 | 2061 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2062 | */ |
2063 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2064 | |
2065 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2066 | pmd_populate(mm, &_pmd, pgtable); | |
2067 | ||
2068 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2069 | pte_t *pte, entry; | |
2070 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2071 | entry = pte_mkspecial(entry); | |
2072 | pte = pte_offset_map(&_pmd, haddr); | |
2073 | VM_BUG_ON(!pte_none(*pte)); | |
2074 | set_pte_at(mm, haddr, pte, entry); | |
2075 | pte_unmap(pte); | |
2076 | } | |
2077 | smp_wmb(); /* make pte visible before pmd */ | |
2078 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2079 | } |
2080 | ||
2081 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2082 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2083 | { |
2084 | struct mm_struct *mm = vma->vm_mm; | |
2085 | struct page *page; | |
2086 | pgtable_t pgtable; | |
423ac9af | 2087 | pmd_t old_pmd, _pmd; |
a3cf988f | 2088 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2089 | unsigned long addr; |
eef1b3ba KS |
2090 | int i; |
2091 | ||
2092 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2093 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2094 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2095 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2096 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2097 | |
2098 | count_vm_event(THP_SPLIT_PMD); | |
2099 | ||
d21b9e57 KS |
2100 | if (!vma_is_anonymous(vma)) { |
2101 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2102 | /* |
2103 | * We are going to unmap this huge page. So | |
2104 | * just go ahead and zap it | |
2105 | */ | |
2106 | if (arch_needs_pgtable_deposit()) | |
2107 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2108 | if (vma_is_dax(vma)) |
2109 | return; | |
2110 | page = pmd_page(_pmd); | |
e1f1b157 HD |
2111 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2112 | set_page_dirty(page); | |
d21b9e57 KS |
2113 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2114 | SetPageReferenced(page); | |
2115 | page_remove_rmap(page, true); | |
2116 | put_page(page); | |
fadae295 | 2117 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba KS |
2118 | return; |
2119 | } else if (is_huge_zero_pmd(*pmd)) { | |
4645b9fe JG |
2120 | /* |
2121 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2122 | * mmu_notifier_invalidate_range() see comments below inside | |
2123 | * __split_huge_pmd() ? | |
2124 | * | |
2125 | * We are going from a zero huge page write protected to zero | |
2126 | * small page also write protected so it does not seems useful | |
2127 | * to invalidate secondary mmu at this time. | |
2128 | */ | |
eef1b3ba KS |
2129 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2130 | } | |
2131 | ||
423ac9af AK |
2132 | /* |
2133 | * Up to this point the pmd is present and huge and userland has the | |
2134 | * whole access to the hugepage during the split (which happens in | |
2135 | * place). If we overwrite the pmd with the not-huge version pointing | |
2136 | * to the pte here (which of course we could if all CPUs were bug | |
2137 | * free), userland could trigger a small page size TLB miss on the | |
2138 | * small sized TLB while the hugepage TLB entry is still established in | |
2139 | * the huge TLB. Some CPU doesn't like that. | |
2140 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2141 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2142 | * only safe if the permission and cache attributes of the two entries | |
2143 | * loaded in the two TLB is identical (which should be the case here). | |
2144 | * But it is generally safer to never allow small and huge TLB entries | |
2145 | * for the same virtual address to be loaded simultaneously. So instead | |
2146 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2147 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2148 | * must remain set at all times on the pmd until the split is complete | |
2149 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2150 | * non-huge version of the pmd entry with pmd_populate. | |
2151 | */ | |
2152 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2153 | ||
423ac9af | 2154 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2155 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2156 | swp_entry_t entry; |
2157 | ||
423ac9af | 2158 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e | 2159 | page = pfn_to_page(swp_offset(entry)); |
2e83ee1d PX |
2160 | write = is_write_migration_entry(entry); |
2161 | young = false; | |
2162 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
2163 | } else { | |
423ac9af | 2164 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2165 | if (pmd_dirty(old_pmd)) |
2166 | SetPageDirty(page); | |
2167 | write = pmd_write(old_pmd); | |
2168 | young = pmd_young(old_pmd); | |
2169 | soft_dirty = pmd_soft_dirty(old_pmd); | |
2170 | } | |
eef1b3ba | 2171 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2172 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2173 | |
423ac9af AK |
2174 | /* |
2175 | * Withdraw the table only after we mark the pmd entry invalid. | |
2176 | * This's critical for some architectures (Power). | |
2177 | */ | |
eef1b3ba KS |
2178 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2179 | pmd_populate(mm, &_pmd, pgtable); | |
2180 | ||
2ac015e2 | 2181 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2182 | pte_t entry, *pte; |
2183 | /* | |
2184 | * Note that NUMA hinting access restrictions are not | |
2185 | * transferred to avoid any possibility of altering | |
2186 | * permissions across VMAs. | |
2187 | */ | |
84c3fc4e | 2188 | if (freeze || pmd_migration) { |
ba988280 KS |
2189 | swp_entry_t swp_entry; |
2190 | swp_entry = make_migration_entry(page + i, write); | |
2191 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2192 | if (soft_dirty) |
2193 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2194 | } else { |
6d2329f8 | 2195 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2196 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2197 | if (!write) |
2198 | entry = pte_wrprotect(entry); | |
2199 | if (!young) | |
2200 | entry = pte_mkold(entry); | |
804dd150 AA |
2201 | if (soft_dirty) |
2202 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2203 | } |
2ac015e2 | 2204 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2205 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2206 | set_pte_at(mm, addr, pte, entry); |
eef1b3ba KS |
2207 | atomic_inc(&page[i]._mapcount); |
2208 | pte_unmap(pte); | |
2209 | } | |
2210 | ||
2211 | /* | |
2212 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2213 | * false-negative page_mapped(). | |
2214 | */ | |
2215 | if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) { | |
2216 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2217 | atomic_inc(&page[i]._mapcount); | |
2218 | } | |
2219 | ||
2220 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2221 | /* Last compound_mapcount is gone. */ | |
11fb9989 | 2222 | __dec_node_page_state(page, NR_ANON_THPS); |
eef1b3ba KS |
2223 | if (TestClearPageDoubleMap(page)) { |
2224 | /* No need in mapcount reference anymore */ | |
2225 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2226 | atomic_dec(&page[i]._mapcount); | |
2227 | } | |
2228 | } | |
2229 | ||
2230 | smp_wmb(); /* make pte visible before pmd */ | |
2231 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2232 | |
2233 | if (freeze) { | |
2ac015e2 | 2234 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2235 | page_remove_rmap(page + i, false); |
2236 | put_page(page + i); | |
2237 | } | |
2238 | } | |
eef1b3ba KS |
2239 | } |
2240 | ||
2241 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2242 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2243 | { |
2244 | spinlock_t *ptl; | |
ac46d4f3 | 2245 | struct mmu_notifier_range range; |
eef1b3ba | 2246 | |
ac46d4f3 JG |
2247 | mmu_notifier_range_init(&range, vma->vm_mm, address & HPAGE_PMD_MASK, |
2248 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); | |
2249 | mmu_notifier_invalidate_range_start(&range); | |
2250 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2251 | |
2252 | /* | |
2253 | * If caller asks to setup a migration entries, we need a page to check | |
2254 | * pmd against. Otherwise we can end up replacing wrong page. | |
2255 | */ | |
2256 | VM_BUG_ON(freeze && !page); | |
2257 | if (page && page != pmd_page(*pmd)) | |
2258 | goto out; | |
2259 | ||
5c7fb56e | 2260 | if (pmd_trans_huge(*pmd)) { |
33f4751e | 2261 | page = pmd_page(*pmd); |
5c7fb56e | 2262 | if (PageMlocked(page)) |
5f737714 | 2263 | clear_page_mlock(page); |
84c3fc4e | 2264 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2265 | goto out; |
ac46d4f3 | 2266 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2267 | out: |
eef1b3ba | 2268 | spin_unlock(ptl); |
4645b9fe JG |
2269 | /* |
2270 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2271 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2272 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2273 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2274 | * fault will trigger a flush_notify before pointing to a new page | |
2275 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2276 | * page in the meantime) | |
2277 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2278 | * to invalidate secondary tlb entry they are all still valid. | |
2279 | * any further changes to individual pte will notify. So no need | |
2280 | * to call mmu_notifier->invalidate_range() | |
2281 | */ | |
ac46d4f3 | 2282 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2283 | } |
2284 | ||
fec89c10 KS |
2285 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2286 | bool freeze, struct page *page) | |
94fcc585 | 2287 | { |
f72e7dcd | 2288 | pgd_t *pgd; |
c2febafc | 2289 | p4d_t *p4d; |
f72e7dcd | 2290 | pud_t *pud; |
94fcc585 AA |
2291 | pmd_t *pmd; |
2292 | ||
78ddc534 | 2293 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2294 | if (!pgd_present(*pgd)) |
2295 | return; | |
2296 | ||
c2febafc KS |
2297 | p4d = p4d_offset(pgd, address); |
2298 | if (!p4d_present(*p4d)) | |
2299 | return; | |
2300 | ||
2301 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2302 | if (!pud_present(*pud)) |
2303 | return; | |
2304 | ||
2305 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2306 | |
33f4751e | 2307 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2308 | } |
2309 | ||
e1b9996b | 2310 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2311 | unsigned long start, |
2312 | unsigned long end, | |
2313 | long adjust_next) | |
2314 | { | |
2315 | /* | |
2316 | * If the new start address isn't hpage aligned and it could | |
2317 | * previously contain an hugepage: check if we need to split | |
2318 | * an huge pmd. | |
2319 | */ | |
2320 | if (start & ~HPAGE_PMD_MASK && | |
2321 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2322 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2323 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2324 | |
2325 | /* | |
2326 | * If the new end address isn't hpage aligned and it could | |
2327 | * previously contain an hugepage: check if we need to split | |
2328 | * an huge pmd. | |
2329 | */ | |
2330 | if (end & ~HPAGE_PMD_MASK && | |
2331 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2332 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2333 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2334 | |
2335 | /* | |
2336 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2337 | * vm_next->vm_start isn't page aligned and it could previously | |
2338 | * contain an hugepage: check if we need to split an huge pmd. | |
2339 | */ | |
2340 | if (adjust_next > 0) { | |
2341 | struct vm_area_struct *next = vma->vm_next; | |
2342 | unsigned long nstart = next->vm_start; | |
2343 | nstart += adjust_next << PAGE_SHIFT; | |
2344 | if (nstart & ~HPAGE_PMD_MASK && | |
2345 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2346 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2347 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2348 | } |
2349 | } | |
e9b61f19 | 2350 | |
906f9cdf | 2351 | static void unmap_page(struct page *page) |
e9b61f19 | 2352 | { |
baa355fd | 2353 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
c7ab0d2f | 2354 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2355 | bool unmap_success; |
e9b61f19 KS |
2356 | |
2357 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2358 | ||
baa355fd | 2359 | if (PageAnon(page)) |
b5ff8161 | 2360 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2361 | |
666e5a40 MK |
2362 | unmap_success = try_to_unmap(page, ttu_flags); |
2363 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2364 | } |
2365 | ||
906f9cdf | 2366 | static void remap_page(struct page *page) |
e9b61f19 | 2367 | { |
fec89c10 | 2368 | int i; |
ace71a19 KS |
2369 | if (PageTransHuge(page)) { |
2370 | remove_migration_ptes(page, page, true); | |
2371 | } else { | |
2372 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2373 | remove_migration_ptes(page + i, page + i, true); | |
2374 | } | |
e9b61f19 KS |
2375 | } |
2376 | ||
8df651c7 | 2377 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2378 | struct lruvec *lruvec, struct list_head *list) |
2379 | { | |
e9b61f19 KS |
2380 | struct page *page_tail = head + tail; |
2381 | ||
8df651c7 | 2382 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2383 | |
2384 | /* | |
605ca5ed KK |
2385 | * Clone page flags before unfreezing refcount. |
2386 | * | |
2387 | * After successful get_page_unless_zero() might follow flags change, | |
2388 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2389 | */ |
e9b61f19 KS |
2390 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2391 | page_tail->flags |= (head->flags & | |
2392 | ((1L << PG_referenced) | | |
2393 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2394 | (1L << PG_swapcache) | |
e9b61f19 KS |
2395 | (1L << PG_mlocked) | |
2396 | (1L << PG_uptodate) | | |
2397 | (1L << PG_active) | | |
1899ad18 | 2398 | (1L << PG_workingset) | |
e9b61f19 | 2399 | (1L << PG_locked) | |
b8d3c4c3 MK |
2400 | (1L << PG_unevictable) | |
2401 | (1L << PG_dirty))); | |
e9b61f19 | 2402 | |
173d9d9f HD |
2403 | /* ->mapping in first tail page is compound_mapcount */ |
2404 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2405 | page_tail); | |
2406 | page_tail->mapping = head->mapping; | |
2407 | page_tail->index = head->index + tail; | |
2408 | ||
605ca5ed | 2409 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2410 | smp_wmb(); |
2411 | ||
605ca5ed KK |
2412 | /* |
2413 | * Clear PageTail before unfreezing page refcount. | |
2414 | * | |
2415 | * After successful get_page_unless_zero() might follow put_page() | |
2416 | * which needs correct compound_head(). | |
2417 | */ | |
e9b61f19 KS |
2418 | clear_compound_head(page_tail); |
2419 | ||
605ca5ed KK |
2420 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2421 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2422 | PageSwapCache(head))); | |
2423 | ||
e9b61f19 KS |
2424 | if (page_is_young(head)) |
2425 | set_page_young(page_tail); | |
2426 | if (page_is_idle(head)) | |
2427 | set_page_idle(page_tail); | |
2428 | ||
e9b61f19 | 2429 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2430 | |
2431 | /* | |
2432 | * always add to the tail because some iterators expect new | |
2433 | * pages to show after the currently processed elements - e.g. | |
2434 | * migrate_pages | |
2435 | */ | |
e9b61f19 | 2436 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2437 | } |
2438 | ||
baa355fd | 2439 | static void __split_huge_page(struct page *page, struct list_head *list, |
006d3ff2 | 2440 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2441 | { |
2442 | struct page *head = compound_head(page); | |
2443 | struct zone *zone = page_zone(head); | |
2444 | struct lruvec *lruvec; | |
8df651c7 | 2445 | int i; |
e9b61f19 | 2446 | |
599d0c95 | 2447 | lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); |
e9b61f19 KS |
2448 | |
2449 | /* complete memcg works before add pages to LRU */ | |
2450 | mem_cgroup_split_huge_fixup(head); | |
2451 | ||
baa355fd | 2452 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2453 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2454 | /* Some pages can be beyond i_size: drop them from page cache */ |
2455 | if (head[i].index >= end) { | |
2d077d4b | 2456 | ClearPageDirty(head + i); |
baa355fd | 2457 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2458 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2459 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd KS |
2460 | put_page(head + i); |
2461 | } | |
2462 | } | |
e9b61f19 KS |
2463 | |
2464 | ClearPageCompound(head); | |
baa355fd KS |
2465 | /* See comment in __split_huge_page_tail() */ |
2466 | if (PageAnon(head)) { | |
aa5dc07f | 2467 | /* Additional pin to swap cache */ |
38d8b4e6 HY |
2468 | if (PageSwapCache(head)) |
2469 | page_ref_add(head, 2); | |
2470 | else | |
2471 | page_ref_inc(head); | |
baa355fd | 2472 | } else { |
aa5dc07f | 2473 | /* Additional pin to page cache */ |
baa355fd | 2474 | page_ref_add(head, 2); |
b93b0163 | 2475 | xa_unlock(&head->mapping->i_pages); |
baa355fd KS |
2476 | } |
2477 | ||
a52633d8 | 2478 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
e9b61f19 | 2479 | |
906f9cdf | 2480 | remap_page(head); |
e9b61f19 KS |
2481 | |
2482 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2483 | struct page *subpage = head + i; | |
2484 | if (subpage == page) | |
2485 | continue; | |
2486 | unlock_page(subpage); | |
2487 | ||
2488 | /* | |
2489 | * Subpages may be freed if there wasn't any mapping | |
2490 | * like if add_to_swap() is running on a lru page that | |
2491 | * had its mapping zapped. And freeing these pages | |
2492 | * requires taking the lru_lock so we do the put_page | |
2493 | * of the tail pages after the split is complete. | |
2494 | */ | |
2495 | put_page(subpage); | |
2496 | } | |
2497 | } | |
2498 | ||
b20ce5e0 KS |
2499 | int total_mapcount(struct page *page) |
2500 | { | |
dd78fedd | 2501 | int i, compound, ret; |
b20ce5e0 KS |
2502 | |
2503 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2504 | ||
2505 | if (likely(!PageCompound(page))) | |
2506 | return atomic_read(&page->_mapcount) + 1; | |
2507 | ||
dd78fedd | 2508 | compound = compound_mapcount(page); |
b20ce5e0 | 2509 | if (PageHuge(page)) |
dd78fedd KS |
2510 | return compound; |
2511 | ret = compound; | |
b20ce5e0 KS |
2512 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2513 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2514 | /* File pages has compound_mapcount included in _mapcount */ |
2515 | if (!PageAnon(page)) | |
2516 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2517 | if (PageDoubleMap(page)) |
2518 | ret -= HPAGE_PMD_NR; | |
2519 | return ret; | |
2520 | } | |
2521 | ||
6d0a07ed AA |
2522 | /* |
2523 | * This calculates accurately how many mappings a transparent hugepage | |
2524 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2525 | * accuracy is primarily needed to know if copy-on-write faults can | |
2526 | * reuse the page and change the mapping to read-write instead of | |
2527 | * copying them. At the same time this returns the total_mapcount too. | |
2528 | * | |
2529 | * The function returns the highest mapcount any one of the subpages | |
2530 | * has. If the return value is one, even if different processes are | |
2531 | * mapping different subpages of the transparent hugepage, they can | |
2532 | * all reuse it, because each process is reusing a different subpage. | |
2533 | * | |
2534 | * The total_mapcount is instead counting all virtual mappings of the | |
2535 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2536 | * caller all mappings belong to the same "mm" and in turn the | |
2537 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2538 | * local one as no other process may be mapping any of the subpages. | |
2539 | * | |
2540 | * It would be more accurate to replace page_mapcount() with | |
2541 | * page_trans_huge_mapcount(), however we only use | |
2542 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2543 | * need full accuracy to avoid breaking page pinning, because | |
2544 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2545 | */ | |
2546 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2547 | { | |
2548 | int i, ret, _total_mapcount, mapcount; | |
2549 | ||
2550 | /* hugetlbfs shouldn't call it */ | |
2551 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2552 | ||
2553 | if (likely(!PageTransCompound(page))) { | |
2554 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2555 | if (total_mapcount) | |
2556 | *total_mapcount = mapcount; | |
2557 | return mapcount; | |
2558 | } | |
2559 | ||
2560 | page = compound_head(page); | |
2561 | ||
2562 | _total_mapcount = ret = 0; | |
2563 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2564 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2565 | ret = max(ret, mapcount); | |
2566 | _total_mapcount += mapcount; | |
2567 | } | |
2568 | if (PageDoubleMap(page)) { | |
2569 | ret -= 1; | |
2570 | _total_mapcount -= HPAGE_PMD_NR; | |
2571 | } | |
2572 | mapcount = compound_mapcount(page); | |
2573 | ret += mapcount; | |
2574 | _total_mapcount += mapcount; | |
2575 | if (total_mapcount) | |
2576 | *total_mapcount = _total_mapcount; | |
2577 | return ret; | |
2578 | } | |
2579 | ||
b8f593cd HY |
2580 | /* Racy check whether the huge page can be split */ |
2581 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2582 | { | |
2583 | int extra_pins; | |
2584 | ||
aa5dc07f | 2585 | /* Additional pins from page cache */ |
b8f593cd HY |
2586 | if (PageAnon(page)) |
2587 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2588 | else | |
2589 | extra_pins = HPAGE_PMD_NR; | |
2590 | if (pextra_pins) | |
2591 | *pextra_pins = extra_pins; | |
2592 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2593 | } | |
2594 | ||
e9b61f19 KS |
2595 | /* |
2596 | * This function splits huge page into normal pages. @page can point to any | |
2597 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2598 | * | |
2599 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2600 | * The huge page must be locked. | |
2601 | * | |
2602 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2603 | * | |
2604 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2605 | * the hugepage. | |
2606 | * | |
2607 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2608 | * they are not mapped. | |
2609 | * | |
2610 | * Returns 0 if the hugepage is split successfully. | |
2611 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2612 | * us. | |
2613 | */ | |
2614 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2615 | { | |
2616 | struct page *head = compound_head(page); | |
a3d0a918 | 2617 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
baa355fd KS |
2618 | struct anon_vma *anon_vma = NULL; |
2619 | struct address_space *mapping = NULL; | |
2620 | int count, mapcount, extra_pins, ret; | |
d9654322 | 2621 | bool mlocked; |
0b9b6fff | 2622 | unsigned long flags; |
006d3ff2 | 2623 | pgoff_t end; |
e9b61f19 KS |
2624 | |
2625 | VM_BUG_ON_PAGE(is_huge_zero_page(page), page); | |
e9b61f19 | 2626 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2627 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2628 | ||
59807685 HY |
2629 | if (PageWriteback(page)) |
2630 | return -EBUSY; | |
2631 | ||
baa355fd KS |
2632 | if (PageAnon(head)) { |
2633 | /* | |
2634 | * The caller does not necessarily hold an mmap_sem that would | |
2635 | * prevent the anon_vma disappearing so we first we take a | |
2636 | * reference to it and then lock the anon_vma for write. This | |
2637 | * is similar to page_lock_anon_vma_read except the write lock | |
2638 | * is taken to serialise against parallel split or collapse | |
2639 | * operations. | |
2640 | */ | |
2641 | anon_vma = page_get_anon_vma(head); | |
2642 | if (!anon_vma) { | |
2643 | ret = -EBUSY; | |
2644 | goto out; | |
2645 | } | |
006d3ff2 | 2646 | end = -1; |
baa355fd KS |
2647 | mapping = NULL; |
2648 | anon_vma_lock_write(anon_vma); | |
2649 | } else { | |
2650 | mapping = head->mapping; | |
2651 | ||
2652 | /* Truncated ? */ | |
2653 | if (!mapping) { | |
2654 | ret = -EBUSY; | |
2655 | goto out; | |
2656 | } | |
2657 | ||
baa355fd KS |
2658 | anon_vma = NULL; |
2659 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2660 | |
2661 | /* | |
2662 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2663 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2664 | * which cannot be nested inside the page tree lock. So note | |
2665 | * end now: i_size itself may be changed at any moment, but | |
2666 | * head page lock is good enough to serialize the trimming. | |
2667 | */ | |
2668 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2669 | } |
e9b61f19 KS |
2670 | |
2671 | /* | |
906f9cdf | 2672 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2673 | * split PMDs |
2674 | */ | |
b8f593cd | 2675 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2676 | ret = -EBUSY; |
2677 | goto out_unlock; | |
2678 | } | |
2679 | ||
d9654322 | 2680 | mlocked = PageMlocked(page); |
906f9cdf | 2681 | unmap_page(head); |
e9b61f19 KS |
2682 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2683 | ||
d9654322 KS |
2684 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2685 | if (mlocked) | |
2686 | lru_add_drain(); | |
2687 | ||
baa355fd | 2688 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
a52633d8 | 2689 | spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags); |
baa355fd KS |
2690 | |
2691 | if (mapping) { | |
aa5dc07f | 2692 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2693 | |
baa355fd | 2694 | /* |
aa5dc07f | 2695 | * Check if the head page is present in page cache. |
baa355fd KS |
2696 | * We assume all tail are present too, if head is there. |
2697 | */ | |
aa5dc07f MW |
2698 | xa_lock(&mapping->i_pages); |
2699 | if (xas_load(&xas) != head) | |
baa355fd KS |
2700 | goto fail; |
2701 | } | |
2702 | ||
0139aa7b | 2703 | /* Prevent deferred_split_scan() touching ->_refcount */ |
baa355fd | 2704 | spin_lock(&pgdata->split_queue_lock); |
e9b61f19 KS |
2705 | count = page_count(head); |
2706 | mapcount = total_mapcount(head); | |
baa355fd | 2707 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2708 | if (!list_empty(page_deferred_list(head))) { |
a3d0a918 | 2709 | pgdata->split_queue_len--; |
9a982250 KS |
2710 | list_del(page_deferred_list(head)); |
2711 | } | |
65c45377 | 2712 | if (mapping) |
11fb9989 | 2713 | __dec_node_page_state(page, NR_SHMEM_THPS); |
baa355fd | 2714 | spin_unlock(&pgdata->split_queue_lock); |
006d3ff2 | 2715 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2716 | if (PageSwapCache(head)) { |
2717 | swp_entry_t entry = { .val = page_private(head) }; | |
2718 | ||
2719 | ret = split_swap_cluster(entry); | |
2720 | } else | |
2721 | ret = 0; | |
e9b61f19 | 2722 | } else { |
baa355fd KS |
2723 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2724 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2725 | mapcount, count); | |
2726 | if (PageTail(page)) | |
2727 | dump_page(head, NULL); | |
2728 | dump_page(page, "total_mapcount(head) > 0"); | |
2729 | BUG(); | |
2730 | } | |
2731 | spin_unlock(&pgdata->split_queue_lock); | |
2732 | fail: if (mapping) | |
b93b0163 | 2733 | xa_unlock(&mapping->i_pages); |
a52633d8 | 2734 | spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); |
906f9cdf | 2735 | remap_page(head); |
e9b61f19 KS |
2736 | ret = -EBUSY; |
2737 | } | |
2738 | ||
2739 | out_unlock: | |
baa355fd KS |
2740 | if (anon_vma) { |
2741 | anon_vma_unlock_write(anon_vma); | |
2742 | put_anon_vma(anon_vma); | |
2743 | } | |
2744 | if (mapping) | |
2745 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2746 | out: |
2747 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2748 | return ret; | |
2749 | } | |
9a982250 KS |
2750 | |
2751 | void free_transhuge_page(struct page *page) | |
2752 | { | |
a3d0a918 | 2753 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2754 | unsigned long flags; |
2755 | ||
a3d0a918 | 2756 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2757 | if (!list_empty(page_deferred_list(page))) { |
a3d0a918 | 2758 | pgdata->split_queue_len--; |
9a982250 KS |
2759 | list_del(page_deferred_list(page)); |
2760 | } | |
a3d0a918 | 2761 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2762 | free_compound_page(page); |
2763 | } | |
2764 | ||
2765 | void deferred_split_huge_page(struct page *page) | |
2766 | { | |
a3d0a918 | 2767 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(page)); |
9a982250 KS |
2768 | unsigned long flags; |
2769 | ||
2770 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2771 | ||
a3d0a918 | 2772 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2773 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2774 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
a3d0a918 KS |
2775 | list_add_tail(page_deferred_list(page), &pgdata->split_queue); |
2776 | pgdata->split_queue_len++; | |
9a982250 | 2777 | } |
a3d0a918 | 2778 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2779 | } |
2780 | ||
2781 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2782 | struct shrink_control *sc) | |
2783 | { | |
a3d0a918 | 2784 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
6aa7de05 | 2785 | return READ_ONCE(pgdata->split_queue_len); |
9a982250 KS |
2786 | } |
2787 | ||
2788 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2789 | struct shrink_control *sc) | |
2790 | { | |
a3d0a918 | 2791 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
9a982250 KS |
2792 | unsigned long flags; |
2793 | LIST_HEAD(list), *pos, *next; | |
2794 | struct page *page; | |
2795 | int split = 0; | |
2796 | ||
a3d0a918 | 2797 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
9a982250 | 2798 | /* Take pin on all head pages to avoid freeing them under us */ |
ae026204 | 2799 | list_for_each_safe(pos, next, &pgdata->split_queue) { |
9a982250 KS |
2800 | page = list_entry((void *)pos, struct page, mapping); |
2801 | page = compound_head(page); | |
e3ae1953 KS |
2802 | if (get_page_unless_zero(page)) { |
2803 | list_move(page_deferred_list(page), &list); | |
2804 | } else { | |
2805 | /* We lost race with put_compound_page() */ | |
9a982250 | 2806 | list_del_init(page_deferred_list(page)); |
a3d0a918 | 2807 | pgdata->split_queue_len--; |
9a982250 | 2808 | } |
e3ae1953 KS |
2809 | if (!--sc->nr_to_scan) |
2810 | break; | |
9a982250 | 2811 | } |
a3d0a918 | 2812 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); |
9a982250 KS |
2813 | |
2814 | list_for_each_safe(pos, next, &list) { | |
2815 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2816 | if (!trylock_page(page)) |
2817 | goto next; | |
9a982250 KS |
2818 | /* split_huge_page() removes page from list on success */ |
2819 | if (!split_huge_page(page)) | |
2820 | split++; | |
2821 | unlock_page(page); | |
fa41b900 | 2822 | next: |
9a982250 KS |
2823 | put_page(page); |
2824 | } | |
2825 | ||
a3d0a918 KS |
2826 | spin_lock_irqsave(&pgdata->split_queue_lock, flags); |
2827 | list_splice_tail(&list, &pgdata->split_queue); | |
2828 | spin_unlock_irqrestore(&pgdata->split_queue_lock, flags); | |
9a982250 | 2829 | |
cb8d68ec KS |
2830 | /* |
2831 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2832 | * This can happen if pages were freed under us. | |
2833 | */ | |
2834 | if (!split && list_empty(&pgdata->split_queue)) | |
2835 | return SHRINK_STOP; | |
2836 | return split; | |
9a982250 KS |
2837 | } |
2838 | ||
2839 | static struct shrinker deferred_split_shrinker = { | |
2840 | .count_objects = deferred_split_count, | |
2841 | .scan_objects = deferred_split_scan, | |
2842 | .seeks = DEFAULT_SEEKS, | |
a3d0a918 | 2843 | .flags = SHRINKER_NUMA_AWARE, |
9a982250 | 2844 | }; |
49071d43 KS |
2845 | |
2846 | #ifdef CONFIG_DEBUG_FS | |
2847 | static int split_huge_pages_set(void *data, u64 val) | |
2848 | { | |
2849 | struct zone *zone; | |
2850 | struct page *page; | |
2851 | unsigned long pfn, max_zone_pfn; | |
2852 | unsigned long total = 0, split = 0; | |
2853 | ||
2854 | if (val != 1) | |
2855 | return -EINVAL; | |
2856 | ||
2857 | for_each_populated_zone(zone) { | |
2858 | max_zone_pfn = zone_end_pfn(zone); | |
2859 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2860 | if (!pfn_valid(pfn)) | |
2861 | continue; | |
2862 | ||
2863 | page = pfn_to_page(pfn); | |
2864 | if (!get_page_unless_zero(page)) | |
2865 | continue; | |
2866 | ||
2867 | if (zone != page_zone(page)) | |
2868 | goto next; | |
2869 | ||
baa355fd | 2870 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2871 | goto next; |
2872 | ||
2873 | total++; | |
2874 | lock_page(page); | |
2875 | if (!split_huge_page(page)) | |
2876 | split++; | |
2877 | unlock_page(page); | |
2878 | next: | |
2879 | put_page(page); | |
2880 | } | |
2881 | } | |
2882 | ||
145bdaa1 | 2883 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
2884 | |
2885 | return 0; | |
2886 | } | |
2887 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
2888 | "%llu\n"); | |
2889 | ||
2890 | static int __init split_huge_pages_debugfs(void) | |
2891 | { | |
d9f7979c GKH |
2892 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
2893 | &split_huge_pages_fops); | |
49071d43 KS |
2894 | return 0; |
2895 | } | |
2896 | late_initcall(split_huge_pages_debugfs); | |
2897 | #endif | |
616b8371 ZY |
2898 | |
2899 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
2900 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
2901 | struct page *page) | |
2902 | { | |
2903 | struct vm_area_struct *vma = pvmw->vma; | |
2904 | struct mm_struct *mm = vma->vm_mm; | |
2905 | unsigned long address = pvmw->address; | |
2906 | pmd_t pmdval; | |
2907 | swp_entry_t entry; | |
ab6e3d09 | 2908 | pmd_t pmdswp; |
616b8371 ZY |
2909 | |
2910 | if (!(pvmw->pmd && !pvmw->pte)) | |
2911 | return; | |
2912 | ||
616b8371 ZY |
2913 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
2914 | pmdval = *pvmw->pmd; | |
2915 | pmdp_invalidate(vma, address, pvmw->pmd); | |
2916 | if (pmd_dirty(pmdval)) | |
2917 | set_page_dirty(page); | |
2918 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
2919 | pmdswp = swp_entry_to_pmd(entry); |
2920 | if (pmd_soft_dirty(pmdval)) | |
2921 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
2922 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
2923 | page_remove_rmap(page, true); |
2924 | put_page(page); | |
616b8371 ZY |
2925 | } |
2926 | ||
2927 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
2928 | { | |
2929 | struct vm_area_struct *vma = pvmw->vma; | |
2930 | struct mm_struct *mm = vma->vm_mm; | |
2931 | unsigned long address = pvmw->address; | |
2932 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
2933 | pmd_t pmde; | |
2934 | swp_entry_t entry; | |
2935 | ||
2936 | if (!(pvmw->pmd && !pvmw->pte)) | |
2937 | return; | |
2938 | ||
2939 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
2940 | get_page(new); | |
2941 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
2942 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
2943 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 2944 | if (is_write_migration_entry(entry)) |
f55e1014 | 2945 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
2946 | |
2947 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
2948 | if (PageAnon(new)) |
2949 | page_add_anon_rmap(new, vma, mmun_start, true); | |
2950 | else | |
2951 | page_add_file_rmap(new, true); | |
616b8371 | 2952 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 2953 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
2954 | mlock_vma_page(new); |
2955 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
2956 | } | |
2957 | #endif |