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20c8ccb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
71e3aac0 AA |
2 | /* |
3 | * Copyright (C) 2009 Red Hat, Inc. | |
71e3aac0 AA |
4 | */ |
5 | ||
ae3a8c1c AM |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | ||
71e3aac0 AA |
8 | #include <linux/mm.h> |
9 | #include <linux/sched.h> | |
f7ccbae4 | 10 | #include <linux/sched/coredump.h> |
6a3827d7 | 11 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
12 | #include <linux/highmem.h> |
13 | #include <linux/hugetlb.h> | |
14 | #include <linux/mmu_notifier.h> | |
15 | #include <linux/rmap.h> | |
16 | #include <linux/swap.h> | |
97ae1749 | 17 | #include <linux/shrinker.h> |
ba76149f | 18 | #include <linux/mm_inline.h> |
e9b61f19 | 19 | #include <linux/swapops.h> |
4897c765 | 20 | #include <linux/dax.h> |
ba76149f | 21 | #include <linux/khugepaged.h> |
878aee7d | 22 | #include <linux/freezer.h> |
f25748e3 | 23 | #include <linux/pfn_t.h> |
a664b2d8 | 24 | #include <linux/mman.h> |
3565fce3 | 25 | #include <linux/memremap.h> |
325adeb5 | 26 | #include <linux/pagemap.h> |
49071d43 | 27 | #include <linux/debugfs.h> |
4daae3b4 | 28 | #include <linux/migrate.h> |
43b5fbbd | 29 | #include <linux/hashtable.h> |
6b251fc9 | 30 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 31 | #include <linux/page_idle.h> |
baa355fd | 32 | #include <linux/shmem_fs.h> |
6b31d595 | 33 | #include <linux/oom.h> |
98fa15f3 | 34 | #include <linux/numa.h> |
f7da677b | 35 | #include <linux/page_owner.h> |
97ae1749 | 36 | |
71e3aac0 AA |
37 | #include <asm/tlb.h> |
38 | #include <asm/pgalloc.h> | |
39 | #include "internal.h" | |
40 | ||
ba76149f | 41 | /* |
b14d595a MD |
42 | * By default, transparent hugepage support is disabled in order to avoid |
43 | * risking an increased memory footprint for applications that are not | |
44 | * guaranteed to benefit from it. When transparent hugepage support is | |
45 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
46 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
47 | * for all hugepage allocations. | |
ba76149f | 48 | */ |
71e3aac0 | 49 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 50 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 51 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
52 | #endif |
53 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
54 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
55 | #endif | |
444eb2a4 | 56 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
57 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
58 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 59 | |
9a982250 | 60 | static struct shrinker deferred_split_shrinker; |
f000565a | 61 | |
97ae1749 | 62 | static atomic_t huge_zero_refcount; |
56873f43 | 63 | struct page *huge_zero_page __read_mostly; |
352e32f8 | 64 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 65 | |
7635d9cb MH |
66 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
67 | { | |
c0630669 YS |
68 | /* The addr is used to check if the vma size fits */ |
69 | unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; | |
70 | ||
71 | if (!transhuge_vma_suitable(vma, addr)) | |
72 | return false; | |
7635d9cb MH |
73 | if (vma_is_anonymous(vma)) |
74 | return __transparent_hugepage_enabled(vma); | |
c0630669 YS |
75 | if (vma_is_shmem(vma)) |
76 | return shmem_huge_enabled(vma); | |
7635d9cb MH |
77 | |
78 | return false; | |
79 | } | |
80 | ||
6fcb52a5 | 81 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
82 | { |
83 | struct page *zero_page; | |
84 | retry: | |
85 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
4db0c3c2 | 86 | return READ_ONCE(huge_zero_page); |
97ae1749 KS |
87 | |
88 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 89 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
90 | if (!zero_page) { |
91 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 92 | return NULL; |
d8a8e1f0 KS |
93 | } |
94 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 95 | preempt_disable(); |
5918d10a | 96 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 97 | preempt_enable(); |
5ddacbe9 | 98 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
99 | goto retry; |
100 | } | |
352e32f8 | 101 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
102 | |
103 | /* We take additional reference here. It will be put back by shrinker */ | |
104 | atomic_set(&huge_zero_refcount, 2); | |
105 | preempt_enable(); | |
4db0c3c2 | 106 | return READ_ONCE(huge_zero_page); |
4a6c1297 KS |
107 | } |
108 | ||
6fcb52a5 | 109 | static void put_huge_zero_page(void) |
4a6c1297 | 110 | { |
97ae1749 KS |
111 | /* |
112 | * Counter should never go to zero here. Only shrinker can put | |
113 | * last reference. | |
114 | */ | |
115 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
116 | } |
117 | ||
6fcb52a5 AL |
118 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
119 | { | |
120 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
121 | return READ_ONCE(huge_zero_page); | |
122 | ||
123 | if (!get_huge_zero_page()) | |
124 | return NULL; | |
125 | ||
126 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
127 | put_huge_zero_page(); | |
128 | ||
129 | return READ_ONCE(huge_zero_page); | |
130 | } | |
131 | ||
132 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
133 | { | |
134 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
135 | put_huge_zero_page(); | |
136 | } | |
137 | ||
48896466 GC |
138 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
139 | struct shrink_control *sc) | |
4a6c1297 | 140 | { |
48896466 GC |
141 | /* we can free zero page only if last reference remains */ |
142 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
143 | } | |
97ae1749 | 144 | |
48896466 GC |
145 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
146 | struct shrink_control *sc) | |
147 | { | |
97ae1749 | 148 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
149 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
150 | BUG_ON(zero_page == NULL); | |
352e32f8 | 151 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 152 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 153 | return HPAGE_PMD_NR; |
97ae1749 KS |
154 | } |
155 | ||
156 | return 0; | |
4a6c1297 KS |
157 | } |
158 | ||
97ae1749 | 159 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
160 | .count_objects = shrink_huge_zero_page_count, |
161 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
162 | .seeks = DEFAULT_SEEKS, |
163 | }; | |
164 | ||
71e3aac0 | 165 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
166 | static ssize_t enabled_show(struct kobject *kobj, |
167 | struct kobj_attribute *attr, char *buf) | |
168 | { | |
444eb2a4 MG |
169 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
170 | return sprintf(buf, "[always] madvise never\n"); | |
171 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
172 | return sprintf(buf, "always [madvise] never\n"); | |
173 | else | |
174 | return sprintf(buf, "always madvise [never]\n"); | |
71e3aac0 | 175 | } |
444eb2a4 | 176 | |
71e3aac0 AA |
177 | static ssize_t enabled_store(struct kobject *kobj, |
178 | struct kobj_attribute *attr, | |
179 | const char *buf, size_t count) | |
180 | { | |
21440d7e | 181 | ssize_t ret = count; |
ba76149f | 182 | |
9570d539 | 183 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
184 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
185 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
9570d539 | 186 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
187 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
188 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
9570d539 | 189 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
190 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
191 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
192 | } else | |
193 | ret = -EINVAL; | |
ba76149f AA |
194 | |
195 | if (ret > 0) { | |
b46e756f | 196 | int err = start_stop_khugepaged(); |
ba76149f AA |
197 | if (err) |
198 | ret = err; | |
199 | } | |
ba76149f | 200 | return ret; |
71e3aac0 AA |
201 | } |
202 | static struct kobj_attribute enabled_attr = | |
203 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
204 | ||
b46e756f | 205 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
71e3aac0 AA |
206 | struct kobj_attribute *attr, char *buf, |
207 | enum transparent_hugepage_flag flag) | |
208 | { | |
e27e6151 BH |
209 | return sprintf(buf, "%d\n", |
210 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 211 | } |
e27e6151 | 212 | |
b46e756f | 213 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
214 | struct kobj_attribute *attr, |
215 | const char *buf, size_t count, | |
216 | enum transparent_hugepage_flag flag) | |
217 | { | |
e27e6151 BH |
218 | unsigned long value; |
219 | int ret; | |
220 | ||
221 | ret = kstrtoul(buf, 10, &value); | |
222 | if (ret < 0) | |
223 | return ret; | |
224 | if (value > 1) | |
225 | return -EINVAL; | |
226 | ||
227 | if (value) | |
71e3aac0 | 228 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 229 | else |
71e3aac0 | 230 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
231 | |
232 | return count; | |
233 | } | |
234 | ||
71e3aac0 AA |
235 | static ssize_t defrag_show(struct kobject *kobj, |
236 | struct kobj_attribute *attr, char *buf) | |
237 | { | |
444eb2a4 | 238 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
21440d7e | 239 | return sprintf(buf, "[always] defer defer+madvise madvise never\n"); |
444eb2a4 | 240 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
21440d7e DR |
241 | return sprintf(buf, "always [defer] defer+madvise madvise never\n"); |
242 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) | |
243 | return sprintf(buf, "always defer [defer+madvise] madvise never\n"); | |
244 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) | |
245 | return sprintf(buf, "always defer defer+madvise [madvise] never\n"); | |
246 | return sprintf(buf, "always defer defer+madvise madvise [never]\n"); | |
71e3aac0 | 247 | } |
21440d7e | 248 | |
71e3aac0 AA |
249 | static ssize_t defrag_store(struct kobject *kobj, |
250 | struct kobj_attribute *attr, | |
251 | const char *buf, size_t count) | |
252 | { | |
9570d539 | 253 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
254 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
255 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
256 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
257 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
9570d539 | 258 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
259 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
260 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
261 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
262 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
9570d539 | 263 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
264 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
265 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
266 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
267 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
9570d539 | 268 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
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); | |
9570d539 | 273 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
274 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
275 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
276 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
277 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
278 | } else | |
279 | return -EINVAL; | |
280 | ||
281 | return count; | |
71e3aac0 AA |
282 | } |
283 | static struct kobj_attribute defrag_attr = | |
284 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
285 | ||
79da5407 KS |
286 | static ssize_t use_zero_page_show(struct kobject *kobj, |
287 | struct kobj_attribute *attr, char *buf) | |
288 | { | |
b46e756f | 289 | return single_hugepage_flag_show(kobj, attr, buf, |
79da5407 KS |
290 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
291 | } | |
292 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
293 | struct kobj_attribute *attr, const char *buf, size_t count) | |
294 | { | |
b46e756f | 295 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
296 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
297 | } | |
298 | static struct kobj_attribute use_zero_page_attr = | |
299 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
300 | |
301 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
302 | struct kobj_attribute *attr, char *buf) | |
303 | { | |
304 | return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE); | |
305 | } | |
306 | static struct kobj_attribute hpage_pmd_size_attr = | |
307 | __ATTR_RO(hpage_pmd_size); | |
308 | ||
71e3aac0 AA |
309 | #ifdef CONFIG_DEBUG_VM |
310 | static ssize_t debug_cow_show(struct kobject *kobj, | |
311 | struct kobj_attribute *attr, char *buf) | |
312 | { | |
b46e756f | 313 | return single_hugepage_flag_show(kobj, attr, buf, |
71e3aac0 AA |
314 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
315 | } | |
316 | static ssize_t debug_cow_store(struct kobject *kobj, | |
317 | struct kobj_attribute *attr, | |
318 | const char *buf, size_t count) | |
319 | { | |
b46e756f | 320 | return single_hugepage_flag_store(kobj, attr, buf, count, |
71e3aac0 AA |
321 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); |
322 | } | |
323 | static struct kobj_attribute debug_cow_attr = | |
324 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
325 | #endif /* CONFIG_DEBUG_VM */ | |
326 | ||
327 | static struct attribute *hugepage_attr[] = { | |
328 | &enabled_attr.attr, | |
329 | &defrag_attr.attr, | |
79da5407 | 330 | &use_zero_page_attr.attr, |
49920d28 | 331 | &hpage_pmd_size_attr.attr, |
e496cf3d | 332 | #if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) |
5a6e75f8 KS |
333 | &shmem_enabled_attr.attr, |
334 | #endif | |
71e3aac0 AA |
335 | #ifdef CONFIG_DEBUG_VM |
336 | &debug_cow_attr.attr, | |
337 | #endif | |
338 | NULL, | |
339 | }; | |
340 | ||
8aa95a21 | 341 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 342 | .attrs = hugepage_attr, |
ba76149f AA |
343 | }; |
344 | ||
569e5590 | 345 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 346 | { |
71e3aac0 AA |
347 | int err; |
348 | ||
569e5590 SL |
349 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
350 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 351 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 352 | return -ENOMEM; |
ba76149f AA |
353 | } |
354 | ||
569e5590 | 355 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 356 | if (err) { |
ae3a8c1c | 357 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 358 | goto delete_obj; |
ba76149f AA |
359 | } |
360 | ||
569e5590 | 361 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 362 | if (err) { |
ae3a8c1c | 363 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 364 | goto remove_hp_group; |
ba76149f | 365 | } |
569e5590 SL |
366 | |
367 | return 0; | |
368 | ||
369 | remove_hp_group: | |
370 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
371 | delete_obj: | |
372 | kobject_put(*hugepage_kobj); | |
373 | return err; | |
374 | } | |
375 | ||
376 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
377 | { | |
378 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
379 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
380 | kobject_put(hugepage_kobj); | |
381 | } | |
382 | #else | |
383 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
384 | { | |
385 | return 0; | |
386 | } | |
387 | ||
388 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
389 | { | |
390 | } | |
391 | #endif /* CONFIG_SYSFS */ | |
392 | ||
393 | static int __init hugepage_init(void) | |
394 | { | |
395 | int err; | |
396 | struct kobject *hugepage_kobj; | |
397 | ||
398 | if (!has_transparent_hugepage()) { | |
399 | transparent_hugepage_flags = 0; | |
400 | return -EINVAL; | |
401 | } | |
402 | ||
ff20c2e0 KS |
403 | /* |
404 | * hugepages can't be allocated by the buddy allocator | |
405 | */ | |
406 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
407 | /* | |
408 | * we use page->mapping and page->index in second tail page | |
409 | * as list_head: assuming THP order >= 2 | |
410 | */ | |
411 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
412 | ||
569e5590 SL |
413 | err = hugepage_init_sysfs(&hugepage_kobj); |
414 | if (err) | |
65ebb64f | 415 | goto err_sysfs; |
ba76149f | 416 | |
b46e756f | 417 | err = khugepaged_init(); |
ba76149f | 418 | if (err) |
65ebb64f | 419 | goto err_slab; |
ba76149f | 420 | |
65ebb64f KS |
421 | err = register_shrinker(&huge_zero_page_shrinker); |
422 | if (err) | |
423 | goto err_hzp_shrinker; | |
9a982250 KS |
424 | err = register_shrinker(&deferred_split_shrinker); |
425 | if (err) | |
426 | goto err_split_shrinker; | |
97ae1749 | 427 | |
97562cd2 RR |
428 | /* |
429 | * By default disable transparent hugepages on smaller systems, | |
430 | * where the extra memory used could hurt more than TLB overhead | |
431 | * is likely to save. The admin can still enable it through /sys. | |
432 | */ | |
ca79b0c2 | 433 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 434 | transparent_hugepage_flags = 0; |
79553da2 KS |
435 | return 0; |
436 | } | |
97562cd2 | 437 | |
79553da2 | 438 | err = start_stop_khugepaged(); |
65ebb64f KS |
439 | if (err) |
440 | goto err_khugepaged; | |
ba76149f | 441 | |
569e5590 | 442 | return 0; |
65ebb64f | 443 | err_khugepaged: |
9a982250 KS |
444 | unregister_shrinker(&deferred_split_shrinker); |
445 | err_split_shrinker: | |
65ebb64f KS |
446 | unregister_shrinker(&huge_zero_page_shrinker); |
447 | err_hzp_shrinker: | |
b46e756f | 448 | khugepaged_destroy(); |
65ebb64f | 449 | err_slab: |
569e5590 | 450 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 451 | err_sysfs: |
ba76149f | 452 | return err; |
71e3aac0 | 453 | } |
a64fb3cd | 454 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
455 | |
456 | static int __init setup_transparent_hugepage(char *str) | |
457 | { | |
458 | int ret = 0; | |
459 | if (!str) | |
460 | goto out; | |
461 | if (!strcmp(str, "always")) { | |
462 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
463 | &transparent_hugepage_flags); | |
464 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
465 | &transparent_hugepage_flags); | |
466 | ret = 1; | |
467 | } else if (!strcmp(str, "madvise")) { | |
468 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
469 | &transparent_hugepage_flags); | |
470 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
471 | &transparent_hugepage_flags); | |
472 | ret = 1; | |
473 | } else if (!strcmp(str, "never")) { | |
474 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
475 | &transparent_hugepage_flags); | |
476 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
477 | &transparent_hugepage_flags); | |
478 | ret = 1; | |
479 | } | |
480 | out: | |
481 | if (!ret) | |
ae3a8c1c | 482 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
483 | return ret; |
484 | } | |
485 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
486 | ||
f55e1014 | 487 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 488 | { |
f55e1014 | 489 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
490 | pmd = pmd_mkwrite(pmd); |
491 | return pmd; | |
492 | } | |
493 | ||
87eaceb3 YS |
494 | #ifdef CONFIG_MEMCG |
495 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 496 | { |
87eaceb3 YS |
497 | struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; |
498 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
499 | ||
500 | if (memcg) | |
501 | return &memcg->deferred_split_queue; | |
502 | else | |
503 | return &pgdat->deferred_split_queue; | |
9a982250 | 504 | } |
87eaceb3 YS |
505 | #else |
506 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
507 | { | |
508 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
509 | ||
510 | return &pgdat->deferred_split_queue; | |
511 | } | |
512 | #endif | |
9a982250 KS |
513 | |
514 | void prep_transhuge_page(struct page *page) | |
515 | { | |
516 | /* | |
517 | * we use page->mapping and page->indexlru in second tail page | |
518 | * as list_head: assuming THP order >= 2 | |
519 | */ | |
9a982250 KS |
520 | |
521 | INIT_LIST_HEAD(page_deferred_list(page)); | |
522 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
523 | } | |
524 | ||
3424999c KS |
525 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
526 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
527 | loff_t off, unsigned long flags, unsigned long size) |
528 | { | |
74d2fad1 TK |
529 | loff_t off_end = off + len; |
530 | loff_t off_align = round_up(off, size); | |
3424999c | 531 | unsigned long len_pad, ret; |
74d2fad1 TK |
532 | |
533 | if (off_end <= off_align || (off_end - off_align) < size) | |
534 | return 0; | |
535 | ||
536 | len_pad = len + size; | |
537 | if (len_pad < len || (off + len_pad) < off) | |
538 | return 0; | |
539 | ||
3424999c | 540 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 541 | off >> PAGE_SHIFT, flags); |
3424999c KS |
542 | |
543 | /* | |
544 | * The failure might be due to length padding. The caller will retry | |
545 | * without the padding. | |
546 | */ | |
547 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
548 | return 0; |
549 | ||
3424999c KS |
550 | /* |
551 | * Do not try to align to THP boundary if allocation at the address | |
552 | * hint succeeds. | |
553 | */ | |
554 | if (ret == addr) | |
555 | return addr; | |
556 | ||
557 | ret += (off - ret) & (size - 1); | |
558 | return ret; | |
74d2fad1 TK |
559 | } |
560 | ||
561 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
562 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
563 | { | |
3424999c | 564 | unsigned long ret; |
74d2fad1 TK |
565 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
566 | ||
74d2fad1 TK |
567 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) |
568 | goto out; | |
569 | ||
3424999c KS |
570 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
571 | if (ret) | |
572 | return ret; | |
573 | out: | |
74d2fad1 TK |
574 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
575 | } | |
576 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
577 | ||
2b740303 SJ |
578 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
579 | struct page *page, gfp_t gfp) | |
71e3aac0 | 580 | { |
82b0f8c3 | 581 | struct vm_area_struct *vma = vmf->vma; |
00501b53 | 582 | struct mem_cgroup *memcg; |
71e3aac0 | 583 | pgtable_t pgtable; |
82b0f8c3 | 584 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 585 | vm_fault_t ret = 0; |
71e3aac0 | 586 | |
309381fe | 587 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 588 | |
2cf85583 | 589 | if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { |
6b251fc9 AA |
590 | put_page(page); |
591 | count_vm_event(THP_FAULT_FALLBACK); | |
592 | return VM_FAULT_FALLBACK; | |
593 | } | |
00501b53 | 594 | |
4cf58924 | 595 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 596 | if (unlikely(!pgtable)) { |
6b31d595 MH |
597 | ret = VM_FAULT_OOM; |
598 | goto release; | |
00501b53 | 599 | } |
71e3aac0 | 600 | |
c79b57e4 | 601 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
602 | /* |
603 | * The memory barrier inside __SetPageUptodate makes sure that | |
604 | * clear_huge_page writes become visible before the set_pmd_at() | |
605 | * write. | |
606 | */ | |
71e3aac0 AA |
607 | __SetPageUptodate(page); |
608 | ||
82b0f8c3 JK |
609 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
610 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 611 | goto unlock_release; |
71e3aac0 AA |
612 | } else { |
613 | pmd_t entry; | |
6b251fc9 | 614 | |
6b31d595 MH |
615 | ret = check_stable_address_space(vma->vm_mm); |
616 | if (ret) | |
617 | goto unlock_release; | |
618 | ||
6b251fc9 AA |
619 | /* Deliver the page fault to userland */ |
620 | if (userfaultfd_missing(vma)) { | |
2b740303 | 621 | vm_fault_t ret2; |
6b251fc9 | 622 | |
82b0f8c3 | 623 | spin_unlock(vmf->ptl); |
f627c2f5 | 624 | mem_cgroup_cancel_charge(page, memcg, true); |
6b251fc9 | 625 | put_page(page); |
bae473a4 | 626 | pte_free(vma->vm_mm, pgtable); |
2b740303 SJ |
627 | ret2 = handle_userfault(vmf, VM_UFFD_MISSING); |
628 | VM_BUG_ON(ret2 & VM_FAULT_FALLBACK); | |
629 | return ret2; | |
6b251fc9 AA |
630 | } |
631 | ||
3122359a | 632 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 633 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 634 | page_add_new_anon_rmap(page, vma, haddr, true); |
f627c2f5 | 635 | mem_cgroup_commit_charge(page, memcg, false, true); |
00501b53 | 636 | lru_cache_add_active_or_unevictable(page, vma); |
82b0f8c3 JK |
637 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
638 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
bae473a4 | 639 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 640 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 641 | spin_unlock(vmf->ptl); |
6b251fc9 | 642 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 643 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
71e3aac0 AA |
644 | } |
645 | ||
aa2e878e | 646 | return 0; |
6b31d595 MH |
647 | unlock_release: |
648 | spin_unlock(vmf->ptl); | |
649 | release: | |
650 | if (pgtable) | |
651 | pte_free(vma->vm_mm, pgtable); | |
652 | mem_cgroup_cancel_charge(page, memcg, true); | |
653 | put_page(page); | |
654 | return ret; | |
655 | ||
71e3aac0 AA |
656 | } |
657 | ||
444eb2a4 | 658 | /* |
21440d7e DR |
659 | * always: directly stall for all thp allocations |
660 | * defer: wake kswapd and fail if not immediately available | |
661 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
662 | * fail if not immediately available | |
663 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
664 | * available | |
665 | * never: never stall for any thp allocation | |
444eb2a4 | 666 | */ |
19deb769 | 667 | static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma) |
444eb2a4 | 668 | { |
21440d7e | 669 | const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 670 | |
ac79f78d | 671 | /* Always do synchronous compaction */ |
a8282608 AA |
672 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
673 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
674 | |
675 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 676 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 677 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
678 | |
679 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 680 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
681 | return GFP_TRANSHUGE_LIGHT | |
682 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
683 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
684 | |
685 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 686 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
687 | return GFP_TRANSHUGE_LIGHT | |
688 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 689 | |
19deb769 | 690 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
691 | } |
692 | ||
c4088ebd | 693 | /* Caller must hold page table lock. */ |
d295e341 | 694 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 695 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 696 | struct page *zero_page) |
fc9fe822 KS |
697 | { |
698 | pmd_t entry; | |
7c414164 AM |
699 | if (!pmd_none(*pmd)) |
700 | return false; | |
5918d10a | 701 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 702 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
703 | if (pgtable) |
704 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 705 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 706 | mm_inc_nr_ptes(mm); |
7c414164 | 707 | return true; |
fc9fe822 KS |
708 | } |
709 | ||
2b740303 | 710 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 711 | { |
82b0f8c3 | 712 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 713 | gfp_t gfp; |
71e3aac0 | 714 | struct page *page; |
82b0f8c3 | 715 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 716 | |
43675e6f | 717 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 718 | return VM_FAULT_FALLBACK; |
128ec037 KS |
719 | if (unlikely(anon_vma_prepare(vma))) |
720 | return VM_FAULT_OOM; | |
6d50e60c | 721 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 722 | return VM_FAULT_OOM; |
82b0f8c3 | 723 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 724 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
725 | transparent_hugepage_use_zero_page()) { |
726 | pgtable_t pgtable; | |
727 | struct page *zero_page; | |
2b740303 | 728 | vm_fault_t ret; |
4cf58924 | 729 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 730 | if (unlikely(!pgtable)) |
ba76149f | 731 | return VM_FAULT_OOM; |
6fcb52a5 | 732 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 733 | if (unlikely(!zero_page)) { |
bae473a4 | 734 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 735 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 736 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 737 | } |
82b0f8c3 | 738 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 739 | ret = 0; |
82b0f8c3 | 740 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
741 | ret = check_stable_address_space(vma->vm_mm); |
742 | if (ret) { | |
743 | spin_unlock(vmf->ptl); | |
b605278d | 744 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 745 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 746 | spin_unlock(vmf->ptl); |
b605278d | 747 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 748 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
749 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
750 | } else { | |
bae473a4 | 751 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 JK |
752 | haddr, vmf->pmd, zero_page); |
753 | spin_unlock(vmf->ptl); | |
6b251fc9 | 754 | } |
b605278d | 755 | } else { |
82b0f8c3 | 756 | spin_unlock(vmf->ptl); |
bae473a4 | 757 | pte_free(vma->vm_mm, pgtable); |
b605278d | 758 | } |
6b251fc9 | 759 | return ret; |
71e3aac0 | 760 | } |
19deb769 DR |
761 | gfp = alloc_hugepage_direct_gfpmask(vma); |
762 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); | |
128ec037 KS |
763 | if (unlikely(!page)) { |
764 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 765 | return VM_FAULT_FALLBACK; |
128ec037 | 766 | } |
9a982250 | 767 | prep_transhuge_page(page); |
82b0f8c3 | 768 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
769 | } |
770 | ||
ae18d6dc | 771 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
772 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
773 | pgtable_t pgtable) | |
5cad465d MW |
774 | { |
775 | struct mm_struct *mm = vma->vm_mm; | |
776 | pmd_t entry; | |
777 | spinlock_t *ptl; | |
778 | ||
779 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
780 | if (!pmd_none(*pmd)) { |
781 | if (write) { | |
782 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
783 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
784 | goto out_unlock; | |
785 | } | |
786 | entry = pmd_mkyoung(*pmd); | |
787 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
788 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
789 | update_mmu_cache_pmd(vma, addr, pmd); | |
790 | } | |
791 | ||
792 | goto out_unlock; | |
793 | } | |
794 | ||
f25748e3 DW |
795 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
796 | if (pfn_t_devmap(pfn)) | |
797 | entry = pmd_mkdevmap(entry); | |
01871e59 | 798 | if (write) { |
f55e1014 LT |
799 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
800 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 801 | } |
3b6521f5 OH |
802 | |
803 | if (pgtable) { | |
804 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 805 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 806 | pgtable = NULL; |
3b6521f5 OH |
807 | } |
808 | ||
01871e59 RZ |
809 | set_pmd_at(mm, addr, pmd, entry); |
810 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
811 | |
812 | out_unlock: | |
5cad465d | 813 | spin_unlock(ptl); |
c6f3c5ee AK |
814 | if (pgtable) |
815 | pte_free(mm, pgtable); | |
5cad465d MW |
816 | } |
817 | ||
fce86ff5 | 818 | vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) |
5cad465d | 819 | { |
fce86ff5 DW |
820 | unsigned long addr = vmf->address & PMD_MASK; |
821 | struct vm_area_struct *vma = vmf->vma; | |
5cad465d | 822 | pgprot_t pgprot = vma->vm_page_prot; |
3b6521f5 | 823 | pgtable_t pgtable = NULL; |
fce86ff5 | 824 | |
5cad465d MW |
825 | /* |
826 | * If we had pmd_special, we could avoid all these restrictions, | |
827 | * but we need to be consistent with PTEs and architectures that | |
828 | * can't support a 'special' bit. | |
829 | */ | |
e1fb4a08 DJ |
830 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
831 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
832 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
833 | (VM_PFNMAP|VM_MIXEDMAP)); | |
834 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
835 | |
836 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
837 | return VM_FAULT_SIGBUS; | |
308a047c | 838 | |
3b6521f5 | 839 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 840 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
841 | if (!pgtable) |
842 | return VM_FAULT_OOM; | |
843 | } | |
844 | ||
308a047c BP |
845 | track_pfn_insert(vma, &pgprot, pfn); |
846 | ||
fce86ff5 | 847 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 848 | return VM_FAULT_NOPAGE; |
5cad465d | 849 | } |
dee41079 | 850 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); |
5cad465d | 851 | |
a00cc7d9 | 852 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 853 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 854 | { |
f55e1014 | 855 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
856 | pud = pud_mkwrite(pud); |
857 | return pud; | |
858 | } | |
859 | ||
860 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
861 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
862 | { | |
863 | struct mm_struct *mm = vma->vm_mm; | |
864 | pud_t entry; | |
865 | spinlock_t *ptl; | |
866 | ||
867 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
868 | if (!pud_none(*pud)) { |
869 | if (write) { | |
870 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
871 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
872 | goto out_unlock; | |
873 | } | |
874 | entry = pud_mkyoung(*pud); | |
875 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
876 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
877 | update_mmu_cache_pud(vma, addr, pud); | |
878 | } | |
879 | goto out_unlock; | |
880 | } | |
881 | ||
a00cc7d9 MW |
882 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
883 | if (pfn_t_devmap(pfn)) | |
884 | entry = pud_mkdevmap(entry); | |
885 | if (write) { | |
f55e1014 LT |
886 | entry = pud_mkyoung(pud_mkdirty(entry)); |
887 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
888 | } |
889 | set_pud_at(mm, addr, pud, entry); | |
890 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
891 | |
892 | out_unlock: | |
a00cc7d9 MW |
893 | spin_unlock(ptl); |
894 | } | |
895 | ||
fce86ff5 | 896 | vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) |
a00cc7d9 | 897 | { |
fce86ff5 DW |
898 | unsigned long addr = vmf->address & PUD_MASK; |
899 | struct vm_area_struct *vma = vmf->vma; | |
a00cc7d9 | 900 | pgprot_t pgprot = vma->vm_page_prot; |
fce86ff5 | 901 | |
a00cc7d9 MW |
902 | /* |
903 | * If we had pud_special, we could avoid all these restrictions, | |
904 | * but we need to be consistent with PTEs and architectures that | |
905 | * can't support a 'special' bit. | |
906 | */ | |
62ec0d8c DJ |
907 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
908 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
909 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
910 | (VM_PFNMAP|VM_MIXEDMAP)); | |
911 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
912 | |
913 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
914 | return VM_FAULT_SIGBUS; | |
915 | ||
916 | track_pfn_insert(vma, &pgprot, pfn); | |
917 | ||
fce86ff5 | 918 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
919 | return VM_FAULT_NOPAGE; |
920 | } | |
921 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); | |
922 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
923 | ||
3565fce3 | 924 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 925 | pmd_t *pmd, int flags) |
3565fce3 DW |
926 | { |
927 | pmd_t _pmd; | |
928 | ||
a8f97366 KS |
929 | _pmd = pmd_mkyoung(*pmd); |
930 | if (flags & FOLL_WRITE) | |
931 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 932 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 933 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
934 | update_mmu_cache_pmd(vma, addr, pmd); |
935 | } | |
936 | ||
937 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 938 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
939 | { |
940 | unsigned long pfn = pmd_pfn(*pmd); | |
941 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
942 | struct page *page; |
943 | ||
944 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
945 | ||
8310d48b KF |
946 | /* |
947 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
948 | * not be in this function with `flags & FOLL_COW` set. | |
949 | */ | |
950 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
951 | ||
f6f37321 | 952 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
953 | return NULL; |
954 | ||
955 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
956 | /* pass */; | |
957 | else | |
958 | return NULL; | |
959 | ||
960 | if (flags & FOLL_TOUCH) | |
a8f97366 | 961 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
962 | |
963 | /* | |
964 | * device mapped pages can only be returned if the | |
965 | * caller will manage the page reference count. | |
966 | */ | |
967 | if (!(flags & FOLL_GET)) | |
968 | return ERR_PTR(-EEXIST); | |
969 | ||
970 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
971 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
972 | if (!*pgmap) | |
3565fce3 DW |
973 | return ERR_PTR(-EFAULT); |
974 | page = pfn_to_page(pfn); | |
975 | get_page(page); | |
3565fce3 DW |
976 | |
977 | return page; | |
978 | } | |
979 | ||
71e3aac0 AA |
980 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
981 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
982 | struct vm_area_struct *vma) | |
983 | { | |
c4088ebd | 984 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
985 | struct page *src_page; |
986 | pmd_t pmd; | |
12c9d70b | 987 | pgtable_t pgtable = NULL; |
628d47ce | 988 | int ret = -ENOMEM; |
71e3aac0 | 989 | |
628d47ce KS |
990 | /* Skip if can be re-fill on fault */ |
991 | if (!vma_is_anonymous(vma)) | |
992 | return 0; | |
993 | ||
4cf58924 | 994 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
995 | if (unlikely(!pgtable)) |
996 | goto out; | |
71e3aac0 | 997 | |
c4088ebd KS |
998 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
999 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1000 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1001 | |
1002 | ret = -EAGAIN; | |
1003 | pmd = *src_pmd; | |
84c3fc4e ZY |
1004 | |
1005 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1006 | if (unlikely(is_swap_pmd(pmd))) { | |
1007 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1008 | ||
1009 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
1010 | if (is_write_migration_entry(entry)) { | |
1011 | make_migration_entry_read(&entry); | |
1012 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1013 | if (pmd_swp_soft_dirty(*src_pmd)) |
1014 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
1015 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1016 | } | |
dd8a67f9 | 1017 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1018 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1019 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
1020 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1021 | ret = 0; | |
1022 | goto out_unlock; | |
1023 | } | |
1024 | #endif | |
1025 | ||
628d47ce | 1026 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1027 | pte_free(dst_mm, pgtable); |
1028 | goto out_unlock; | |
1029 | } | |
fc9fe822 | 1030 | /* |
c4088ebd | 1031 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1032 | * under splitting since we don't split the page itself, only pmd to |
1033 | * a page table. | |
1034 | */ | |
1035 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 1036 | struct page *zero_page; |
97ae1749 KS |
1037 | /* |
1038 | * get_huge_zero_page() will never allocate a new page here, | |
1039 | * since we already have a zero page to copy. It just takes a | |
1040 | * reference. | |
1041 | */ | |
6fcb52a5 | 1042 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 1043 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 1044 | zero_page); |
fc9fe822 KS |
1045 | ret = 0; |
1046 | goto out_unlock; | |
1047 | } | |
de466bd6 | 1048 | |
628d47ce KS |
1049 | src_page = pmd_page(pmd); |
1050 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
1051 | get_page(src_page); | |
1052 | page_dup_rmap(src_page, true); | |
1053 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 1054 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1055 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
1056 | |
1057 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
1058 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
1059 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1060 | |
1061 | ret = 0; | |
1062 | out_unlock: | |
c4088ebd KS |
1063 | spin_unlock(src_ptl); |
1064 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1065 | out: |
1066 | return ret; | |
1067 | } | |
1068 | ||
a00cc7d9 MW |
1069 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1070 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1071 | pud_t *pud, int flags) |
a00cc7d9 MW |
1072 | { |
1073 | pud_t _pud; | |
1074 | ||
a8f97366 KS |
1075 | _pud = pud_mkyoung(*pud); |
1076 | if (flags & FOLL_WRITE) | |
1077 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1078 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1079 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1080 | update_mmu_cache_pud(vma, addr, pud); |
1081 | } | |
1082 | ||
1083 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1084 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1085 | { |
1086 | unsigned long pfn = pud_pfn(*pud); | |
1087 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1088 | struct page *page; |
1089 | ||
1090 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1091 | ||
f6f37321 | 1092 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1093 | return NULL; |
1094 | ||
1095 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1096 | /* pass */; | |
1097 | else | |
1098 | return NULL; | |
1099 | ||
1100 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1101 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1102 | |
1103 | /* | |
1104 | * device mapped pages can only be returned if the | |
1105 | * caller will manage the page reference count. | |
1106 | */ | |
1107 | if (!(flags & FOLL_GET)) | |
1108 | return ERR_PTR(-EEXIST); | |
1109 | ||
1110 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1111 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1112 | if (!*pgmap) | |
a00cc7d9 MW |
1113 | return ERR_PTR(-EFAULT); |
1114 | page = pfn_to_page(pfn); | |
1115 | get_page(page); | |
a00cc7d9 MW |
1116 | |
1117 | return page; | |
1118 | } | |
1119 | ||
1120 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1121 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1122 | struct vm_area_struct *vma) | |
1123 | { | |
1124 | spinlock_t *dst_ptl, *src_ptl; | |
1125 | pud_t pud; | |
1126 | int ret; | |
1127 | ||
1128 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1129 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1130 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1131 | ||
1132 | ret = -EAGAIN; | |
1133 | pud = *src_pud; | |
1134 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1135 | goto out_unlock; | |
1136 | ||
1137 | /* | |
1138 | * When page table lock is held, the huge zero pud should not be | |
1139 | * under splitting since we don't split the page itself, only pud to | |
1140 | * a page table. | |
1141 | */ | |
1142 | if (is_huge_zero_pud(pud)) { | |
1143 | /* No huge zero pud yet */ | |
1144 | } | |
1145 | ||
1146 | pudp_set_wrprotect(src_mm, addr, src_pud); | |
1147 | pud = pud_mkold(pud_wrprotect(pud)); | |
1148 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1149 | ||
1150 | ret = 0; | |
1151 | out_unlock: | |
1152 | spin_unlock(src_ptl); | |
1153 | spin_unlock(dst_ptl); | |
1154 | return ret; | |
1155 | } | |
1156 | ||
1157 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1158 | { | |
1159 | pud_t entry; | |
1160 | unsigned long haddr; | |
1161 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1162 | ||
1163 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1164 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1165 | goto unlock; | |
1166 | ||
1167 | entry = pud_mkyoung(orig_pud); | |
1168 | if (write) | |
1169 | entry = pud_mkdirty(entry); | |
1170 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1171 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1172 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1173 | ||
1174 | unlock: | |
1175 | spin_unlock(vmf->ptl); | |
1176 | } | |
1177 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1178 | ||
82b0f8c3 | 1179 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1180 | { |
1181 | pmd_t entry; | |
1182 | unsigned long haddr; | |
20f664aa | 1183 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1184 | |
82b0f8c3 JK |
1185 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1186 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1187 | goto unlock; |
1188 | ||
1189 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1190 | if (write) |
1191 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1192 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1193 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1194 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1195 | |
1196 | unlock: | |
82b0f8c3 | 1197 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1198 | } |
1199 | ||
2b740303 SJ |
1200 | static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf, |
1201 | pmd_t orig_pmd, struct page *page) | |
71e3aac0 | 1202 | { |
82b0f8c3 JK |
1203 | struct vm_area_struct *vma = vmf->vma; |
1204 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; | |
00501b53 | 1205 | struct mem_cgroup *memcg; |
71e3aac0 AA |
1206 | pgtable_t pgtable; |
1207 | pmd_t _pmd; | |
2b740303 SJ |
1208 | int i; |
1209 | vm_fault_t ret = 0; | |
71e3aac0 | 1210 | struct page **pages; |
ac46d4f3 | 1211 | struct mmu_notifier_range range; |
71e3aac0 | 1212 | |
6da2ec56 KC |
1213 | pages = kmalloc_array(HPAGE_PMD_NR, sizeof(struct page *), |
1214 | GFP_KERNEL); | |
71e3aac0 AA |
1215 | if (unlikely(!pages)) { |
1216 | ret |= VM_FAULT_OOM; | |
1217 | goto out; | |
1218 | } | |
1219 | ||
1220 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
41b6167e | 1221 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE, vma, |
82b0f8c3 | 1222 | vmf->address, page_to_nid(page)); |
b9bbfbe3 | 1223 | if (unlikely(!pages[i] || |
2cf85583 | 1224 | mem_cgroup_try_charge_delay(pages[i], vma->vm_mm, |
bae473a4 | 1225 | GFP_KERNEL, &memcg, false))) { |
b9bbfbe3 | 1226 | if (pages[i]) |
71e3aac0 | 1227 | put_page(pages[i]); |
b9bbfbe3 | 1228 | while (--i >= 0) { |
00501b53 JW |
1229 | memcg = (void *)page_private(pages[i]); |
1230 | set_page_private(pages[i], 0); | |
f627c2f5 KS |
1231 | mem_cgroup_cancel_charge(pages[i], memcg, |
1232 | false); | |
b9bbfbe3 AA |
1233 | put_page(pages[i]); |
1234 | } | |
71e3aac0 AA |
1235 | kfree(pages); |
1236 | ret |= VM_FAULT_OOM; | |
1237 | goto out; | |
1238 | } | |
00501b53 | 1239 | set_page_private(pages[i], (unsigned long)memcg); |
71e3aac0 AA |
1240 | } |
1241 | ||
1242 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1243 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1244 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1245 | __SetPageUptodate(pages[i]); |
1246 | cond_resched(); | |
1247 | } | |
1248 | ||
7269f999 JG |
1249 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1250 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1251 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1252 | |
82b0f8c3 JK |
1253 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1254 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 | 1255 | goto out_free_pages; |
309381fe | 1256 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1257 | |
0f10851e JG |
1258 | /* |
1259 | * Leave pmd empty until pte is filled note we must notify here as | |
1260 | * concurrent CPU thread might write to new page before the call to | |
1261 | * mmu_notifier_invalidate_range_end() happens which can lead to a | |
1262 | * device seeing memory write in different order than CPU. | |
1263 | * | |
ad56b738 | 1264 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 1265 | */ |
82b0f8c3 | 1266 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
71e3aac0 | 1267 | |
82b0f8c3 | 1268 | pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, vmf->pmd); |
bae473a4 | 1269 | pmd_populate(vma->vm_mm, &_pmd, pgtable); |
71e3aac0 AA |
1270 | |
1271 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
bae473a4 | 1272 | pte_t entry; |
71e3aac0 AA |
1273 | entry = mk_pte(pages[i], vma->vm_page_prot); |
1274 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
00501b53 JW |
1275 | memcg = (void *)page_private(pages[i]); |
1276 | set_page_private(pages[i], 0); | |
82b0f8c3 | 1277 | page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false); |
f627c2f5 | 1278 | mem_cgroup_commit_charge(pages[i], memcg, false, false); |
00501b53 | 1279 | lru_cache_add_active_or_unevictable(pages[i], vma); |
82b0f8c3 JK |
1280 | vmf->pte = pte_offset_map(&_pmd, haddr); |
1281 | VM_BUG_ON(!pte_none(*vmf->pte)); | |
1282 | set_pte_at(vma->vm_mm, haddr, vmf->pte, entry); | |
1283 | pte_unmap(vmf->pte); | |
71e3aac0 AA |
1284 | } |
1285 | kfree(pages); | |
1286 | ||
71e3aac0 | 1287 | smp_wmb(); /* make pte visible before pmd */ |
82b0f8c3 | 1288 | pmd_populate(vma->vm_mm, vmf->pmd, pgtable); |
d281ee61 | 1289 | page_remove_rmap(page, true); |
82b0f8c3 | 1290 | spin_unlock(vmf->ptl); |
71e3aac0 | 1291 | |
4645b9fe JG |
1292 | /* |
1293 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1294 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1295 | */ | |
ac46d4f3 | 1296 | mmu_notifier_invalidate_range_only_end(&range); |
2ec74c3e | 1297 | |
71e3aac0 AA |
1298 | ret |= VM_FAULT_WRITE; |
1299 | put_page(page); | |
1300 | ||
1301 | out: | |
1302 | return ret; | |
1303 | ||
1304 | out_free_pages: | |
82b0f8c3 | 1305 | spin_unlock(vmf->ptl); |
ac46d4f3 | 1306 | mmu_notifier_invalidate_range_end(&range); |
b9bbfbe3 | 1307 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
00501b53 JW |
1308 | memcg = (void *)page_private(pages[i]); |
1309 | set_page_private(pages[i], 0); | |
f627c2f5 | 1310 | mem_cgroup_cancel_charge(pages[i], memcg, false); |
71e3aac0 | 1311 | put_page(pages[i]); |
b9bbfbe3 | 1312 | } |
71e3aac0 AA |
1313 | kfree(pages); |
1314 | goto out; | |
1315 | } | |
1316 | ||
2b740303 | 1317 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1318 | { |
82b0f8c3 | 1319 | struct vm_area_struct *vma = vmf->vma; |
93b4796d | 1320 | struct page *page = NULL, *new_page; |
00501b53 | 1321 | struct mem_cgroup *memcg; |
82b0f8c3 | 1322 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
ac46d4f3 | 1323 | struct mmu_notifier_range range; |
3b363692 | 1324 | gfp_t huge_gfp; /* for allocation and charge */ |
2b740303 | 1325 | vm_fault_t ret = 0; |
71e3aac0 | 1326 | |
82b0f8c3 | 1327 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1328 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
93b4796d KS |
1329 | if (is_huge_zero_pmd(orig_pmd)) |
1330 | goto alloc; | |
82b0f8c3 JK |
1331 | spin_lock(vmf->ptl); |
1332 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
71e3aac0 AA |
1333 | goto out_unlock; |
1334 | ||
1335 | page = pmd_page(orig_pmd); | |
309381fe | 1336 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
1f25fe20 KS |
1337 | /* |
1338 | * We can only reuse the page if nobody else maps the huge page or it's | |
6d0a07ed | 1339 | * part. |
1f25fe20 | 1340 | */ |
ba3c4ce6 HY |
1341 | if (!trylock_page(page)) { |
1342 | get_page(page); | |
1343 | spin_unlock(vmf->ptl); | |
1344 | lock_page(page); | |
1345 | spin_lock(vmf->ptl); | |
1346 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1347 | unlock_page(page); | |
1348 | put_page(page); | |
1349 | goto out_unlock; | |
1350 | } | |
1351 | put_page(page); | |
1352 | } | |
1353 | if (reuse_swap_page(page, NULL)) { | |
71e3aac0 AA |
1354 | pmd_t entry; |
1355 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1356 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 JK |
1357 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
1358 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
71e3aac0 | 1359 | ret |= VM_FAULT_WRITE; |
ba3c4ce6 | 1360 | unlock_page(page); |
71e3aac0 AA |
1361 | goto out_unlock; |
1362 | } | |
ba3c4ce6 | 1363 | unlock_page(page); |
ddc58f27 | 1364 | get_page(page); |
82b0f8c3 | 1365 | spin_unlock(vmf->ptl); |
93b4796d | 1366 | alloc: |
7635d9cb | 1367 | if (__transparent_hugepage_enabled(vma) && |
077fcf11 | 1368 | !transparent_hugepage_debug_cow()) { |
19deb769 DR |
1369 | huge_gfp = alloc_hugepage_direct_gfpmask(vma); |
1370 | new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER); | |
077fcf11 | 1371 | } else |
71e3aac0 AA |
1372 | new_page = NULL; |
1373 | ||
9a982250 KS |
1374 | if (likely(new_page)) { |
1375 | prep_transhuge_page(new_page); | |
1376 | } else { | |
eecc1e42 | 1377 | if (!page) { |
82b0f8c3 | 1378 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
e9b71ca9 | 1379 | ret |= VM_FAULT_FALLBACK; |
93b4796d | 1380 | } else { |
82b0f8c3 | 1381 | ret = do_huge_pmd_wp_page_fallback(vmf, orig_pmd, page); |
9845cbbd | 1382 | if (ret & VM_FAULT_OOM) { |
82b0f8c3 | 1383 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
9845cbbd KS |
1384 | ret |= VM_FAULT_FALLBACK; |
1385 | } | |
ddc58f27 | 1386 | put_page(page); |
93b4796d | 1387 | } |
17766dde | 1388 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1389 | goto out; |
1390 | } | |
1391 | ||
2cf85583 | 1392 | if (unlikely(mem_cgroup_try_charge_delay(new_page, vma->vm_mm, |
2a70f6a7 | 1393 | huge_gfp, &memcg, true))) { |
b9bbfbe3 | 1394 | put_page(new_page); |
82b0f8c3 | 1395 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
bae473a4 | 1396 | if (page) |
ddc58f27 | 1397 | put_page(page); |
9845cbbd | 1398 | ret |= VM_FAULT_FALLBACK; |
17766dde | 1399 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1400 | goto out; |
1401 | } | |
1402 | ||
17766dde | 1403 | count_vm_event(THP_FAULT_ALLOC); |
1ff9e6e1 | 1404 | count_memcg_events(memcg, THP_FAULT_ALLOC, 1); |
17766dde | 1405 | |
eecc1e42 | 1406 | if (!page) |
c79b57e4 | 1407 | clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR); |
93b4796d | 1408 | else |
c9f4cd71 HY |
1409 | copy_user_huge_page(new_page, page, vmf->address, |
1410 | vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1411 | __SetPageUptodate(new_page); |
1412 | ||
7269f999 JG |
1413 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
1414 | haddr, haddr + HPAGE_PMD_SIZE); | |
ac46d4f3 | 1415 | mmu_notifier_invalidate_range_start(&range); |
2ec74c3e | 1416 | |
82b0f8c3 | 1417 | spin_lock(vmf->ptl); |
93b4796d | 1418 | if (page) |
ddc58f27 | 1419 | put_page(page); |
82b0f8c3 JK |
1420 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { |
1421 | spin_unlock(vmf->ptl); | |
f627c2f5 | 1422 | mem_cgroup_cancel_charge(new_page, memcg, true); |
71e3aac0 | 1423 | put_page(new_page); |
2ec74c3e | 1424 | goto out_mn; |
b9bbfbe3 | 1425 | } else { |
71e3aac0 | 1426 | pmd_t entry; |
3122359a | 1427 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
f55e1014 | 1428 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
82b0f8c3 | 1429 | pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd); |
d281ee61 | 1430 | page_add_new_anon_rmap(new_page, vma, haddr, true); |
f627c2f5 | 1431 | mem_cgroup_commit_charge(new_page, memcg, false, true); |
00501b53 | 1432 | lru_cache_add_active_or_unevictable(new_page, vma); |
82b0f8c3 JK |
1433 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); |
1434 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
eecc1e42 | 1435 | if (!page) { |
bae473a4 | 1436 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 | 1437 | } else { |
309381fe | 1438 | VM_BUG_ON_PAGE(!PageHead(page), page); |
d281ee61 | 1439 | page_remove_rmap(page, true); |
93b4796d KS |
1440 | put_page(page); |
1441 | } | |
71e3aac0 AA |
1442 | ret |= VM_FAULT_WRITE; |
1443 | } | |
82b0f8c3 | 1444 | spin_unlock(vmf->ptl); |
2ec74c3e | 1445 | out_mn: |
4645b9fe JG |
1446 | /* |
1447 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1448 | * the above pmdp_huge_clear_flush_notify() did already call it. | |
1449 | */ | |
ac46d4f3 | 1450 | mmu_notifier_invalidate_range_only_end(&range); |
71e3aac0 AA |
1451 | out: |
1452 | return ret; | |
2ec74c3e | 1453 | out_unlock: |
82b0f8c3 | 1454 | spin_unlock(vmf->ptl); |
2ec74c3e | 1455 | return ret; |
71e3aac0 AA |
1456 | } |
1457 | ||
8310d48b | 1458 | /* |
89468d80 LT |
1459 | * FOLL_FORCE or a forced COW break can write even to unwritable pmd's, |
1460 | * but only after we've gone through a COW cycle and they are dirty. | |
8310d48b KF |
1461 | */ |
1462 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1463 | { | |
89468d80 | 1464 | return pmd_write(pmd) || ((flags & FOLL_COW) && pmd_dirty(pmd)); |
8310d48b KF |
1465 | } |
1466 | ||
b676b293 | 1467 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1468 | unsigned long addr, |
1469 | pmd_t *pmd, | |
1470 | unsigned int flags) | |
1471 | { | |
b676b293 | 1472 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1473 | struct page *page = NULL; |
1474 | ||
c4088ebd | 1475 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1476 | |
8310d48b | 1477 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1478 | goto out; |
1479 | ||
85facf25 KS |
1480 | /* Avoid dumping huge zero page */ |
1481 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1482 | return ERR_PTR(-EFAULT); | |
1483 | ||
2b4847e7 | 1484 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1485 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1486 | goto out; |
1487 | ||
71e3aac0 | 1488 | page = pmd_page(*pmd); |
ca120cf6 | 1489 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3565fce3 | 1490 | if (flags & FOLL_TOUCH) |
a8f97366 | 1491 | touch_pmd(vma, addr, pmd, flags); |
de60f5f1 | 1492 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1493 | /* |
1494 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1495 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1496 | * | |
9a73f61b KS |
1497 | * For anon THP: |
1498 | * | |
e90309c9 KS |
1499 | * In most cases the pmd is the only mapping of the page as we |
1500 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1501 | * writable private mappings in populate_vma_page_range(). | |
1502 | * | |
1503 | * The only scenario when we have the page shared here is if we | |
1504 | * mlocking read-only mapping shared over fork(). We skip | |
1505 | * mlocking such pages. | |
9a73f61b KS |
1506 | * |
1507 | * For file THP: | |
1508 | * | |
1509 | * We can expect PageDoubleMap() to be stable under page lock: | |
1510 | * for file pages we set it in page_add_file_rmap(), which | |
1511 | * requires page to be locked. | |
e90309c9 | 1512 | */ |
9a73f61b KS |
1513 | |
1514 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1515 | goto skip_mlock; | |
1516 | if (PageDoubleMap(page) || !page->mapping) | |
1517 | goto skip_mlock; | |
1518 | if (!trylock_page(page)) | |
1519 | goto skip_mlock; | |
1520 | lru_add_drain(); | |
1521 | if (page->mapping && !PageDoubleMap(page)) | |
1522 | mlock_vma_page(page); | |
1523 | unlock_page(page); | |
b676b293 | 1524 | } |
9a73f61b | 1525 | skip_mlock: |
71e3aac0 | 1526 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1527 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1528 | if (flags & FOLL_GET) |
ddc58f27 | 1529 | get_page(page); |
71e3aac0 AA |
1530 | |
1531 | out: | |
1532 | return page; | |
1533 | } | |
1534 | ||
d10e63f2 | 1535 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1536 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1537 | { |
82b0f8c3 | 1538 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1539 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1540 | struct page *page; |
82b0f8c3 | 1541 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1542 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1543 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1544 | bool page_locked; |
1545 | bool migrated = false; | |
b191f9b1 | 1546 | bool was_writable; |
6688cc05 | 1547 | int flags = 0; |
d10e63f2 | 1548 | |
82b0f8c3 JK |
1549 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1550 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1551 | goto out_unlock; |
1552 | ||
de466bd6 MG |
1553 | /* |
1554 | * If there are potential migrations, wait for completion and retry | |
1555 | * without disrupting NUMA hinting information. Do not relock and | |
1556 | * check_same as the page may no longer be mapped. | |
1557 | */ | |
82b0f8c3 JK |
1558 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1559 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1560 | if (!get_page_unless_zero(page)) |
1561 | goto out_unlock; | |
82b0f8c3 | 1562 | spin_unlock(vmf->ptl); |
9a1ea439 | 1563 | put_and_wait_on_page_locked(page); |
de466bd6 MG |
1564 | goto out; |
1565 | } | |
1566 | ||
d10e63f2 | 1567 | page = pmd_page(pmd); |
a1a46184 | 1568 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1569 | page_nid = page_to_nid(page); |
90572890 | 1570 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1571 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1572 | if (page_nid == this_nid) { |
03c5a6e1 | 1573 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1574 | flags |= TNF_FAULT_LOCAL; |
1575 | } | |
4daae3b4 | 1576 | |
bea66fbd | 1577 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1578 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1579 | flags |= TNF_NO_GROUP; |
1580 | ||
ff9042b1 MG |
1581 | /* |
1582 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1583 | * page_table_lock if at all possible | |
1584 | */ | |
b8916634 MG |
1585 | page_locked = trylock_page(page); |
1586 | target_nid = mpol_misplaced(page, vma, haddr); | |
98fa15f3 | 1587 | if (target_nid == NUMA_NO_NODE) { |
b8916634 | 1588 | /* If the page was locked, there are no parallel migrations */ |
a54a407f | 1589 | if (page_locked) |
b8916634 | 1590 | goto clear_pmdnuma; |
2b4847e7 | 1591 | } |
4daae3b4 | 1592 | |
de466bd6 | 1593 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1594 | if (!page_locked) { |
98fa15f3 | 1595 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1596 | if (!get_page_unless_zero(page)) |
1597 | goto out_unlock; | |
82b0f8c3 | 1598 | spin_unlock(vmf->ptl); |
9a1ea439 | 1599 | put_and_wait_on_page_locked(page); |
b8916634 MG |
1600 | goto out; |
1601 | } | |
1602 | ||
2b4847e7 MG |
1603 | /* |
1604 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1605 | * to serialises splits | |
1606 | */ | |
b8916634 | 1607 | get_page(page); |
82b0f8c3 | 1608 | spin_unlock(vmf->ptl); |
b8916634 | 1609 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1610 | |
c69307d5 | 1611 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1612 | spin_lock(vmf->ptl); |
1613 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1614 | unlock_page(page); |
1615 | put_page(page); | |
98fa15f3 | 1616 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1617 | goto out_unlock; |
b32967ff | 1618 | } |
ff9042b1 | 1619 | |
c3a489ca MG |
1620 | /* Bail if we fail to protect against THP splits for any reason */ |
1621 | if (unlikely(!anon_vma)) { | |
1622 | put_page(page); | |
98fa15f3 | 1623 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1624 | goto clear_pmdnuma; |
1625 | } | |
1626 | ||
8b1b436d PZ |
1627 | /* |
1628 | * Since we took the NUMA fault, we must have observed the !accessible | |
1629 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1630 | * modifying the page we're about to migrate. | |
1631 | * | |
1632 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1633 | * inc_tlb_flush_pending(). |
1634 | * | |
1635 | * We are not sure a pending tlb flush here is for a huge page | |
1636 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1637 | */ |
7066f0f9 | 1638 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1639 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1640 | /* |
1641 | * change_huge_pmd() released the pmd lock before | |
1642 | * invalidating the secondary MMUs sharing the primary | |
1643 | * MMU pagetables (with ->invalidate_range()). The | |
1644 | * mmu_notifier_invalidate_range_end() (which | |
1645 | * internally calls ->invalidate_range()) in | |
1646 | * change_pmd_range() will run after us, so we can't | |
1647 | * rely on it here and we need an explicit invalidate. | |
1648 | */ | |
1649 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1650 | haddr + HPAGE_PMD_SIZE); | |
1651 | } | |
8b1b436d | 1652 | |
a54a407f MG |
1653 | /* |
1654 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1655 | * and access rights restored. |
a54a407f | 1656 | */ |
82b0f8c3 | 1657 | spin_unlock(vmf->ptl); |
8b1b436d | 1658 | |
bae473a4 | 1659 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1660 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1661 | if (migrated) { |
1662 | flags |= TNF_MIGRATED; | |
8191acbd | 1663 | page_nid = target_nid; |
074c2381 MG |
1664 | } else |
1665 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1666 | |
8191acbd | 1667 | goto out; |
b32967ff | 1668 | clear_pmdnuma: |
a54a407f | 1669 | BUG_ON(!PageLocked(page)); |
288bc549 | 1670 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1671 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1672 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1673 | if (was_writable) |
1674 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1675 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1676 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1677 | unlock_page(page); |
d10e63f2 | 1678 | out_unlock: |
82b0f8c3 | 1679 | spin_unlock(vmf->ptl); |
b8916634 MG |
1680 | |
1681 | out: | |
1682 | if (anon_vma) | |
1683 | page_unlock_anon_vma_read(anon_vma); | |
1684 | ||
98fa15f3 | 1685 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1686 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1687 | flags); |
8191acbd | 1688 | |
d10e63f2 MG |
1689 | return 0; |
1690 | } | |
1691 | ||
319904ad HY |
1692 | /* |
1693 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1694 | * Otherwise, return false. | |
1695 | */ | |
1696 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1697 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1698 | { |
1699 | spinlock_t *ptl; | |
1700 | pmd_t orig_pmd; | |
1701 | struct page *page; | |
1702 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1703 | bool ret = false; |
b8d3c4c3 | 1704 | |
ed6a7935 | 1705 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1706 | |
b6ec57f4 KS |
1707 | ptl = pmd_trans_huge_lock(pmd, vma); |
1708 | if (!ptl) | |
25eedabe | 1709 | goto out_unlocked; |
b8d3c4c3 MK |
1710 | |
1711 | orig_pmd = *pmd; | |
319904ad | 1712 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1713 | goto out; |
b8d3c4c3 | 1714 | |
84c3fc4e ZY |
1715 | if (unlikely(!pmd_present(orig_pmd))) { |
1716 | VM_BUG_ON(thp_migration_supported() && | |
1717 | !is_pmd_migration_entry(orig_pmd)); | |
1718 | goto out; | |
1719 | } | |
1720 | ||
b8d3c4c3 MK |
1721 | page = pmd_page(orig_pmd); |
1722 | /* | |
1723 | * If other processes are mapping this page, we couldn't discard | |
1724 | * the page unless they all do MADV_FREE so let's skip the page. | |
1725 | */ | |
879bb16f | 1726 | if (total_mapcount(page) != 1) |
b8d3c4c3 MK |
1727 | goto out; |
1728 | ||
1729 | if (!trylock_page(page)) | |
1730 | goto out; | |
1731 | ||
1732 | /* | |
1733 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1734 | * will deactivate only them. | |
1735 | */ | |
1736 | if (next - addr != HPAGE_PMD_SIZE) { | |
1737 | get_page(page); | |
1738 | spin_unlock(ptl); | |
9818b8cd | 1739 | split_huge_page(page); |
b8d3c4c3 | 1740 | unlock_page(page); |
bbf29ffc | 1741 | put_page(page); |
b8d3c4c3 MK |
1742 | goto out_unlocked; |
1743 | } | |
1744 | ||
1745 | if (PageDirty(page)) | |
1746 | ClearPageDirty(page); | |
1747 | unlock_page(page); | |
1748 | ||
b8d3c4c3 | 1749 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1750 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1751 | orig_pmd = pmd_mkold(orig_pmd); |
1752 | orig_pmd = pmd_mkclean(orig_pmd); | |
1753 | ||
1754 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1755 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1756 | } | |
802a3a92 SL |
1757 | |
1758 | mark_page_lazyfree(page); | |
319904ad | 1759 | ret = true; |
b8d3c4c3 MK |
1760 | out: |
1761 | spin_unlock(ptl); | |
1762 | out_unlocked: | |
1763 | return ret; | |
1764 | } | |
1765 | ||
953c66c2 AK |
1766 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1767 | { | |
1768 | pgtable_t pgtable; | |
1769 | ||
1770 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1771 | pte_free(mm, pgtable); | |
c4812909 | 1772 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1773 | } |
1774 | ||
71e3aac0 | 1775 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1776 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1777 | { |
da146769 | 1778 | pmd_t orig_pmd; |
bf929152 | 1779 | spinlock_t *ptl; |
71e3aac0 | 1780 | |
ed6a7935 | 1781 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1782 | |
b6ec57f4 KS |
1783 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1784 | if (!ptl) | |
da146769 KS |
1785 | return 0; |
1786 | /* | |
1787 | * For architectures like ppc64 we look at deposited pgtable | |
1788 | * when calling pmdp_huge_get_and_clear. So do the | |
1789 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1790 | * operations. | |
1791 | */ | |
1792 | orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd, | |
1793 | tlb->fullmm); | |
1794 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1795 | if (vma_is_dax(vma)) { | |
3b6521f5 OH |
1796 | if (arch_needs_pgtable_deposit()) |
1797 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1798 | spin_unlock(ptl); |
1799 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1800 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1801 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1802 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1803 | spin_unlock(ptl); |
c0f2e176 | 1804 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1805 | } else { |
616b8371 ZY |
1806 | struct page *page = NULL; |
1807 | int flush_needed = 1; | |
1808 | ||
1809 | if (pmd_present(orig_pmd)) { | |
1810 | page = pmd_page(orig_pmd); | |
1811 | page_remove_rmap(page, true); | |
1812 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1813 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1814 | } else if (thp_migration_supported()) { | |
1815 | swp_entry_t entry; | |
1816 | ||
1817 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1818 | entry = pmd_to_swp_entry(orig_pmd); | |
1819 | page = pfn_to_page(swp_offset(entry)); | |
1820 | flush_needed = 0; | |
1821 | } else | |
1822 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1823 | ||
b5072380 | 1824 | if (PageAnon(page)) { |
c14a6eb4 | 1825 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1826 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1827 | } else { | |
953c66c2 AK |
1828 | if (arch_needs_pgtable_deposit()) |
1829 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1830 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1831 | } |
616b8371 | 1832 | |
da146769 | 1833 | spin_unlock(ptl); |
616b8371 ZY |
1834 | if (flush_needed) |
1835 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1836 | } |
da146769 | 1837 | return 1; |
71e3aac0 AA |
1838 | } |
1839 | ||
1dd38b6c AK |
1840 | #ifndef pmd_move_must_withdraw |
1841 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1842 | spinlock_t *old_pmd_ptl, | |
1843 | struct vm_area_struct *vma) | |
1844 | { | |
1845 | /* | |
1846 | * With split pmd lock we also need to move preallocated | |
1847 | * PTE page table if new_pmd is on different PMD page table. | |
1848 | * | |
1849 | * We also don't deposit and withdraw tables for file pages. | |
1850 | */ | |
1851 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1852 | } | |
1853 | #endif | |
1854 | ||
ab6e3d09 NH |
1855 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1856 | { | |
1857 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1858 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1859 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1860 | else if (pmd_present(pmd)) | |
1861 | pmd = pmd_mksoft_dirty(pmd); | |
1862 | #endif | |
1863 | return pmd; | |
1864 | } | |
1865 | ||
bf8616d5 | 1866 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
37a1c49a | 1867 | unsigned long new_addr, unsigned long old_end, |
eb66ae03 | 1868 | pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1869 | { |
bf929152 | 1870 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1871 | pmd_t pmd; |
37a1c49a | 1872 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1873 | bool force_flush = false; |
37a1c49a AA |
1874 | |
1875 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1876 | (new_addr & ~HPAGE_PMD_MASK) || | |
bf8616d5 | 1877 | old_end - old_addr < HPAGE_PMD_SIZE) |
4b471e88 | 1878 | return false; |
37a1c49a AA |
1879 | |
1880 | /* | |
1881 | * The destination pmd shouldn't be established, free_pgtables() | |
1882 | * should have release it. | |
1883 | */ | |
1884 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1885 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1886 | return false; |
37a1c49a AA |
1887 | } |
1888 | ||
bf929152 KS |
1889 | /* |
1890 | * We don't have to worry about the ordering of src and dst | |
1891 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1892 | */ | |
b6ec57f4 KS |
1893 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1894 | if (old_ptl) { | |
bf929152 KS |
1895 | new_ptl = pmd_lockptr(mm, new_pmd); |
1896 | if (new_ptl != old_ptl) | |
1897 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1898 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1899 | if (pmd_present(pmd)) |
a2ce2666 | 1900 | force_flush = true; |
025c5b24 | 1901 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1902 | |
1dd38b6c | 1903 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1904 | pgtable_t pgtable; |
3592806c KS |
1905 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1906 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1907 | } |
ab6e3d09 NH |
1908 | pmd = move_soft_dirty_pmd(pmd); |
1909 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1910 | if (force_flush) |
1911 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1912 | if (new_ptl != old_ptl) |
1913 | spin_unlock(new_ptl); | |
bf929152 | 1914 | spin_unlock(old_ptl); |
4b471e88 | 1915 | return true; |
37a1c49a | 1916 | } |
4b471e88 | 1917 | return false; |
37a1c49a AA |
1918 | } |
1919 | ||
f123d74a MG |
1920 | /* |
1921 | * Returns | |
1922 | * - 0 if PMD could not be locked | |
1923 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1924 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1925 | */ | |
cd7548ab | 1926 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
e944fd67 | 1927 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1928 | { |
1929 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1930 | spinlock_t *ptl; |
0a85e51d KS |
1931 | pmd_t entry; |
1932 | bool preserve_write; | |
1933 | int ret; | |
cd7548ab | 1934 | |
b6ec57f4 | 1935 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1936 | if (!ptl) |
1937 | return 0; | |
e944fd67 | 1938 | |
0a85e51d KS |
1939 | preserve_write = prot_numa && pmd_write(*pmd); |
1940 | ret = 1; | |
e944fd67 | 1941 | |
84c3fc4e ZY |
1942 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1943 | if (is_swap_pmd(*pmd)) { | |
1944 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1945 | ||
1946 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1947 | if (is_write_migration_entry(entry)) { | |
1948 | pmd_t newpmd; | |
1949 | /* | |
1950 | * A protection check is difficult so | |
1951 | * just be safe and disable write | |
1952 | */ | |
1953 | make_migration_entry_read(&entry); | |
1954 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1955 | if (pmd_swp_soft_dirty(*pmd)) |
1956 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1957 | set_pmd_at(mm, addr, pmd, newpmd); |
1958 | } | |
1959 | goto unlock; | |
1960 | } | |
1961 | #endif | |
1962 | ||
0a85e51d KS |
1963 | /* |
1964 | * Avoid trapping faults against the zero page. The read-only | |
1965 | * data is likely to be read-cached on the local CPU and | |
1966 | * local/remote hits to the zero page are not interesting. | |
1967 | */ | |
1968 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1969 | goto unlock; | |
025c5b24 | 1970 | |
0a85e51d KS |
1971 | if (prot_numa && pmd_protnone(*pmd)) |
1972 | goto unlock; | |
1973 | ||
ced10803 KS |
1974 | /* |
1975 | * In case prot_numa, we are under down_read(mmap_sem). It's critical | |
1976 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED | |
1977 | * which is also under down_read(mmap_sem): | |
1978 | * | |
1979 | * CPU0: CPU1: | |
1980 | * change_huge_pmd(prot_numa=1) | |
1981 | * pmdp_huge_get_and_clear_notify() | |
1982 | * madvise_dontneed() | |
1983 | * zap_pmd_range() | |
1984 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1985 | * // skip the pmd | |
1986 | * set_pmd_at(); | |
1987 | * // pmd is re-established | |
1988 | * | |
1989 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1990 | * which may break userspace. | |
1991 | * | |
1992 | * pmdp_invalidate() is required to make sure we don't miss | |
1993 | * dirty/young flags set by hardware. | |
1994 | */ | |
a3cf988f | 1995 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1996 | |
0a85e51d KS |
1997 | entry = pmd_modify(entry, newprot); |
1998 | if (preserve_write) | |
1999 | entry = pmd_mk_savedwrite(entry); | |
2000 | ret = HPAGE_PMD_NR; | |
2001 | set_pmd_at(mm, addr, pmd, entry); | |
2002 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
2003 | unlock: | |
2004 | spin_unlock(ptl); | |
025c5b24 NH |
2005 | return ret; |
2006 | } | |
2007 | ||
2008 | /* | |
8f19b0c0 | 2009 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 2010 | * |
8f19b0c0 HY |
2011 | * Note that if it returns page table lock pointer, this routine returns without |
2012 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 2013 | */ |
b6ec57f4 | 2014 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 2015 | { |
b6ec57f4 KS |
2016 | spinlock_t *ptl; |
2017 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
2018 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
2019 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
2020 | return ptl; |
2021 | spin_unlock(ptl); | |
2022 | return NULL; | |
cd7548ab JW |
2023 | } |
2024 | ||
a00cc7d9 MW |
2025 | /* |
2026 | * Returns true if a given pud maps a thp, false otherwise. | |
2027 | * | |
2028 | * Note that if it returns true, this routine returns without unlocking page | |
2029 | * table lock. So callers must unlock it. | |
2030 | */ | |
2031 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
2032 | { | |
2033 | spinlock_t *ptl; | |
2034 | ||
2035 | ptl = pud_lock(vma->vm_mm, pud); | |
2036 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
2037 | return ptl; | |
2038 | spin_unlock(ptl); | |
2039 | return NULL; | |
2040 | } | |
2041 | ||
2042 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
2043 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
2044 | pud_t *pud, unsigned long addr) | |
2045 | { | |
a00cc7d9 MW |
2046 | spinlock_t *ptl; |
2047 | ||
2048 | ptl = __pud_trans_huge_lock(pud, vma); | |
2049 | if (!ptl) | |
2050 | return 0; | |
2051 | /* | |
2052 | * For architectures like ppc64 we look at deposited pgtable | |
2053 | * when calling pudp_huge_get_and_clear. So do the | |
2054 | * pgtable_trans_huge_withdraw after finishing pudp related | |
2055 | * operations. | |
2056 | */ | |
70516b93 | 2057 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 MW |
2058 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2059 | if (vma_is_dax(vma)) { | |
2060 | spin_unlock(ptl); | |
2061 | /* No zero page support yet */ | |
2062 | } else { | |
2063 | /* No support for anonymous PUD pages yet */ | |
2064 | BUG(); | |
2065 | } | |
2066 | return 1; | |
2067 | } | |
2068 | ||
2069 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2070 | unsigned long haddr) | |
2071 | { | |
2072 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2073 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2074 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2075 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2076 | ||
ce9311cf | 2077 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2078 | |
2079 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2080 | } | |
2081 | ||
2082 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2083 | unsigned long address) | |
2084 | { | |
2085 | spinlock_t *ptl; | |
ac46d4f3 | 2086 | struct mmu_notifier_range range; |
a00cc7d9 | 2087 | |
7269f999 | 2088 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2089 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2090 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2091 | mmu_notifier_invalidate_range_start(&range); | |
2092 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2093 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2094 | goto out; | |
ac46d4f3 | 2095 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2096 | |
2097 | out: | |
2098 | spin_unlock(ptl); | |
4645b9fe JG |
2099 | /* |
2100 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2101 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2102 | */ | |
ac46d4f3 | 2103 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2104 | } |
2105 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2106 | ||
eef1b3ba KS |
2107 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2108 | unsigned long haddr, pmd_t *pmd) | |
2109 | { | |
2110 | struct mm_struct *mm = vma->vm_mm; | |
2111 | pgtable_t pgtable; | |
2112 | pmd_t _pmd; | |
2113 | int i; | |
2114 | ||
0f10851e JG |
2115 | /* |
2116 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2117 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2118 | * replacing a zero pmd write protected page with a zero pte write | |
2119 | * protected page. | |
2120 | * | |
ad56b738 | 2121 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2122 | */ |
2123 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2124 | |
2125 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2126 | pmd_populate(mm, &_pmd, pgtable); | |
2127 | ||
2128 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2129 | pte_t *pte, entry; | |
2130 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2131 | entry = pte_mkspecial(entry); | |
2132 | pte = pte_offset_map(&_pmd, haddr); | |
2133 | VM_BUG_ON(!pte_none(*pte)); | |
2134 | set_pte_at(mm, haddr, pte, entry); | |
2135 | pte_unmap(pte); | |
2136 | } | |
2137 | smp_wmb(); /* make pte visible before pmd */ | |
2138 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2139 | } |
2140 | ||
2141 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2142 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2143 | { |
2144 | struct mm_struct *mm = vma->vm_mm; | |
2145 | struct page *page; | |
2146 | pgtable_t pgtable; | |
423ac9af | 2147 | pmd_t old_pmd, _pmd; |
a3cf988f | 2148 | bool young, write, soft_dirty, pmd_migration = false; |
2ac015e2 | 2149 | unsigned long addr; |
eef1b3ba KS |
2150 | int i; |
2151 | ||
2152 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2153 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2154 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2155 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2156 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2157 | |
2158 | count_vm_event(THP_SPLIT_PMD); | |
2159 | ||
d21b9e57 | 2160 | if (!vma_is_anonymous(vma)) { |
3f78d891 | 2161 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
2162 | /* |
2163 | * We are going to unmap this huge page. So | |
2164 | * just go ahead and zap it | |
2165 | */ | |
2166 | if (arch_needs_pgtable_deposit()) | |
2167 | zap_deposited_table(mm, pmd); | |
d21b9e57 KS |
2168 | if (vma_is_dax(vma)) |
2169 | return; | |
3f78d891 HD |
2170 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
2171 | swp_entry_t entry; | |
2172 | ||
2173 | entry = pmd_to_swp_entry(old_pmd); | |
2174 | page = migration_entry_to_page(entry); | |
2175 | } else { | |
2176 | page = pmd_page(old_pmd); | |
2177 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2178 | set_page_dirty(page); | |
2179 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2180 | SetPageReferenced(page); | |
2181 | page_remove_rmap(page, true); | |
2182 | put_page(page); | |
2183 | } | |
fadae295 | 2184 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2185 | return; |
3f78d891 HD |
2186 | } |
2187 | ||
352e32f8 | 2188 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2189 | /* |
2190 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2191 | * mmu_notifier_invalidate_range() see comments below inside | |
2192 | * __split_huge_pmd() ? | |
2193 | * | |
2194 | * We are going from a zero huge page write protected to zero | |
2195 | * small page also write protected so it does not seems useful | |
2196 | * to invalidate secondary mmu at this time. | |
2197 | */ | |
eef1b3ba KS |
2198 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2199 | } | |
2200 | ||
423ac9af AK |
2201 | /* |
2202 | * Up to this point the pmd is present and huge and userland has the | |
2203 | * whole access to the hugepage during the split (which happens in | |
2204 | * place). If we overwrite the pmd with the not-huge version pointing | |
2205 | * to the pte here (which of course we could if all CPUs were bug | |
2206 | * free), userland could trigger a small page size TLB miss on the | |
2207 | * small sized TLB while the hugepage TLB entry is still established in | |
2208 | * the huge TLB. Some CPU doesn't like that. | |
2209 | * See http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum | |
2210 | * 383 on page 93. Intel should be safe but is also warns that it's | |
2211 | * only safe if the permission and cache attributes of the two entries | |
2212 | * loaded in the two TLB is identical (which should be the case here). | |
2213 | * But it is generally safer to never allow small and huge TLB entries | |
2214 | * for the same virtual address to be loaded simultaneously. So instead | |
2215 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2216 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2217 | * must remain set at all times on the pmd until the split is complete | |
2218 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2219 | * non-huge version of the pmd entry with pmd_populate. | |
2220 | */ | |
2221 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2222 | ||
423ac9af | 2223 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2224 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2225 | swp_entry_t entry; |
2226 | ||
423ac9af | 2227 | entry = pmd_to_swp_entry(old_pmd); |
84c3fc4e | 2228 | page = pfn_to_page(swp_offset(entry)); |
2e83ee1d PX |
2229 | write = is_write_migration_entry(entry); |
2230 | young = false; | |
2231 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
2232 | } else { | |
423ac9af | 2233 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2234 | if (pmd_dirty(old_pmd)) |
2235 | SetPageDirty(page); | |
2236 | write = pmd_write(old_pmd); | |
2237 | young = pmd_young(old_pmd); | |
2238 | soft_dirty = pmd_soft_dirty(old_pmd); | |
2239 | } | |
eef1b3ba | 2240 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2241 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2242 | |
423ac9af AK |
2243 | /* |
2244 | * Withdraw the table only after we mark the pmd entry invalid. | |
2245 | * This's critical for some architectures (Power). | |
2246 | */ | |
eef1b3ba KS |
2247 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2248 | pmd_populate(mm, &_pmd, pgtable); | |
2249 | ||
2ac015e2 | 2250 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2251 | pte_t entry, *pte; |
2252 | /* | |
2253 | * Note that NUMA hinting access restrictions are not | |
2254 | * transferred to avoid any possibility of altering | |
2255 | * permissions across VMAs. | |
2256 | */ | |
84c3fc4e | 2257 | if (freeze || pmd_migration) { |
ba988280 KS |
2258 | swp_entry_t swp_entry; |
2259 | swp_entry = make_migration_entry(page + i, write); | |
2260 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2261 | if (soft_dirty) |
2262 | entry = pte_swp_mksoft_dirty(entry); | |
ba988280 | 2263 | } else { |
6d2329f8 | 2264 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2265 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2266 | if (!write) |
2267 | entry = pte_wrprotect(entry); | |
2268 | if (!young) | |
2269 | entry = pte_mkold(entry); | |
804dd150 AA |
2270 | if (soft_dirty) |
2271 | entry = pte_mksoft_dirty(entry); | |
ba988280 | 2272 | } |
2ac015e2 | 2273 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2274 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2275 | set_pte_at(mm, addr, pte, entry); |
83bc7416 | 2276 | if (!pmd_migration) |
eef1b3ba | 2277 | atomic_inc(&page[i]._mapcount); |
83bc7416 | 2278 | pte_unmap(pte); |
eef1b3ba KS |
2279 | } |
2280 | ||
83bc7416 RC |
2281 | if (!pmd_migration) { |
2282 | /* | |
2283 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2284 | * false-negative page_mapped(). | |
2285 | */ | |
2286 | if (compound_mapcount(page) > 1 && | |
2287 | !TestSetPageDoubleMap(page)) { | |
eef1b3ba | 2288 | for (i = 0; i < HPAGE_PMD_NR; i++) |
83bc7416 RC |
2289 | atomic_inc(&page[i]._mapcount); |
2290 | } | |
2291 | ||
2292 | lock_page_memcg(page); | |
2293 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2294 | /* Last compound_mapcount is gone. */ | |
2295 | __dec_lruvec_page_state(page, NR_ANON_THPS); | |
2296 | if (TestClearPageDoubleMap(page)) { | |
2297 | /* No need in mapcount reference anymore */ | |
2298 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2299 | atomic_dec(&page[i]._mapcount); | |
2300 | } | |
eef1b3ba | 2301 | } |
83bc7416 | 2302 | unlock_page_memcg(page); |
eef1b3ba KS |
2303 | } |
2304 | ||
2305 | smp_wmb(); /* make pte visible before pmd */ | |
2306 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2307 | |
2308 | if (freeze) { | |
2ac015e2 | 2309 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2310 | page_remove_rmap(page + i, false); |
2311 | put_page(page + i); | |
2312 | } | |
2313 | } | |
eef1b3ba KS |
2314 | } |
2315 | ||
2316 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2317 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2318 | { |
2319 | spinlock_t *ptl; | |
ac46d4f3 | 2320 | struct mmu_notifier_range range; |
db31f342 | 2321 | bool do_unlock_page = false; |
484e4094 | 2322 | pmd_t _pmd; |
eef1b3ba | 2323 | |
7269f999 | 2324 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2325 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2326 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2327 | mmu_notifier_invalidate_range_start(&range); | |
2328 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2329 | |
2330 | /* | |
2331 | * If caller asks to setup a migration entries, we need a page to check | |
2332 | * pmd against. Otherwise we can end up replacing wrong page. | |
2333 | */ | |
2334 | VM_BUG_ON(freeze && !page); | |
484e4094 AA |
2335 | if (page) { |
2336 | VM_WARN_ON_ONCE(!PageLocked(page)); | |
484e4094 AA |
2337 | if (page != pmd_page(*pmd)) |
2338 | goto out; | |
2339 | } | |
33f4751e | 2340 | |
484e4094 | 2341 | repeat: |
5c7fb56e | 2342 | if (pmd_trans_huge(*pmd)) { |
484e4094 AA |
2343 | if (!page) { |
2344 | page = pmd_page(*pmd); | |
db31f342 HD |
2345 | /* |
2346 | * An anonymous page must be locked, to ensure that a | |
2347 | * concurrent reuse_swap_page() sees stable mapcount; | |
2348 | * but reuse_swap_page() is not used on shmem or file, | |
2349 | * and page lock must not be taken when zap_pmd_range() | |
2350 | * calls __split_huge_pmd() while i_mmap_lock is held. | |
2351 | */ | |
2352 | if (PageAnon(page)) { | |
2353 | if (unlikely(!trylock_page(page))) { | |
2354 | get_page(page); | |
2355 | _pmd = *pmd; | |
2356 | spin_unlock(ptl); | |
2357 | lock_page(page); | |
2358 | spin_lock(ptl); | |
2359 | if (unlikely(!pmd_same(*pmd, _pmd))) { | |
2360 | unlock_page(page); | |
2361 | put_page(page); | |
2362 | page = NULL; | |
2363 | goto repeat; | |
2364 | } | |
484e4094 | 2365 | put_page(page); |
484e4094 | 2366 | } |
db31f342 | 2367 | do_unlock_page = true; |
484e4094 AA |
2368 | } |
2369 | } | |
5c7fb56e | 2370 | if (PageMlocked(page)) |
5f737714 | 2371 | clear_page_mlock(page); |
84c3fc4e | 2372 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2373 | goto out; |
ac46d4f3 | 2374 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2375 | out: |
eef1b3ba | 2376 | spin_unlock(ptl); |
db31f342 | 2377 | if (do_unlock_page) |
484e4094 | 2378 | unlock_page(page); |
4645b9fe JG |
2379 | /* |
2380 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2381 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2382 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2383 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2384 | * fault will trigger a flush_notify before pointing to a new page | |
2385 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2386 | * page in the meantime) | |
2387 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2388 | * to invalidate secondary tlb entry they are all still valid. | |
2389 | * any further changes to individual pte will notify. So no need | |
2390 | * to call mmu_notifier->invalidate_range() | |
2391 | */ | |
ac46d4f3 | 2392 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2393 | } |
2394 | ||
fec89c10 KS |
2395 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2396 | bool freeze, struct page *page) | |
94fcc585 | 2397 | { |
f72e7dcd | 2398 | pgd_t *pgd; |
c2febafc | 2399 | p4d_t *p4d; |
f72e7dcd | 2400 | pud_t *pud; |
94fcc585 AA |
2401 | pmd_t *pmd; |
2402 | ||
78ddc534 | 2403 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2404 | if (!pgd_present(*pgd)) |
2405 | return; | |
2406 | ||
c2febafc KS |
2407 | p4d = p4d_offset(pgd, address); |
2408 | if (!p4d_present(*p4d)) | |
2409 | return; | |
2410 | ||
2411 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2412 | if (!pud_present(*pud)) |
2413 | return; | |
2414 | ||
2415 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2416 | |
33f4751e | 2417 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2418 | } |
2419 | ||
e1b9996b | 2420 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2421 | unsigned long start, |
2422 | unsigned long end, | |
2423 | long adjust_next) | |
2424 | { | |
2425 | /* | |
2426 | * If the new start address isn't hpage aligned and it could | |
2427 | * previously contain an hugepage: check if we need to split | |
2428 | * an huge pmd. | |
2429 | */ | |
2430 | if (start & ~HPAGE_PMD_MASK && | |
2431 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2432 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2433 | split_huge_pmd_address(vma, start, false, NULL); |
94fcc585 AA |
2434 | |
2435 | /* | |
2436 | * If the new end address isn't hpage aligned and it could | |
2437 | * previously contain an hugepage: check if we need to split | |
2438 | * an huge pmd. | |
2439 | */ | |
2440 | if (end & ~HPAGE_PMD_MASK && | |
2441 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2442 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
fec89c10 | 2443 | split_huge_pmd_address(vma, end, false, NULL); |
94fcc585 AA |
2444 | |
2445 | /* | |
2446 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2447 | * vm_next->vm_start isn't page aligned and it could previously | |
2448 | * contain an hugepage: check if we need to split an huge pmd. | |
2449 | */ | |
2450 | if (adjust_next > 0) { | |
2451 | struct vm_area_struct *next = vma->vm_next; | |
2452 | unsigned long nstart = next->vm_start; | |
2453 | nstart += adjust_next << PAGE_SHIFT; | |
2454 | if (nstart & ~HPAGE_PMD_MASK && | |
2455 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2456 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
fec89c10 | 2457 | split_huge_pmd_address(next, nstart, false, NULL); |
94fcc585 AA |
2458 | } |
2459 | } | |
e9b61f19 | 2460 | |
906f9cdf | 2461 | static void unmap_page(struct page *page) |
e9b61f19 | 2462 | { |
baa355fd | 2463 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | |
10f78390 | 2464 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | TTU_SYNC; |
e9b61f19 KS |
2465 | |
2466 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2467 | ||
baa355fd | 2468 | if (PageAnon(page)) |
b5ff8161 | 2469 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2470 | |
a004628d YS |
2471 | try_to_unmap(page, ttu_flags); |
2472 | ||
2473 | VM_WARN_ON_ONCE_PAGE(page_mapped(page), page); | |
e9b61f19 KS |
2474 | } |
2475 | ||
906f9cdf | 2476 | static void remap_page(struct page *page) |
e9b61f19 | 2477 | { |
fec89c10 | 2478 | int i; |
ace71a19 KS |
2479 | if (PageTransHuge(page)) { |
2480 | remove_migration_ptes(page, page, true); | |
2481 | } else { | |
2482 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2483 | remove_migration_ptes(page + i, page + i, true); | |
2484 | } | |
e9b61f19 KS |
2485 | } |
2486 | ||
8df651c7 | 2487 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2488 | struct lruvec *lruvec, struct list_head *list) |
2489 | { | |
e9b61f19 KS |
2490 | struct page *page_tail = head + tail; |
2491 | ||
8df651c7 | 2492 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2493 | |
2494 | /* | |
605ca5ed KK |
2495 | * Clone page flags before unfreezing refcount. |
2496 | * | |
2497 | * After successful get_page_unless_zero() might follow flags change, | |
2498 | * for exmaple lock_page() which set PG_waiters. | |
e9b61f19 | 2499 | */ |
e9b61f19 KS |
2500 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2501 | page_tail->flags |= (head->flags & | |
2502 | ((1L << PG_referenced) | | |
2503 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2504 | (1L << PG_swapcache) | |
e9b61f19 KS |
2505 | (1L << PG_mlocked) | |
2506 | (1L << PG_uptodate) | | |
2507 | (1L << PG_active) | | |
1899ad18 | 2508 | (1L << PG_workingset) | |
e9b61f19 | 2509 | (1L << PG_locked) | |
b8d3c4c3 MK |
2510 | (1L << PG_unevictable) | |
2511 | (1L << PG_dirty))); | |
e9b61f19 | 2512 | |
173d9d9f HD |
2513 | /* ->mapping in first tail page is compound_mapcount */ |
2514 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2515 | page_tail); | |
2516 | page_tail->mapping = head->mapping; | |
2517 | page_tail->index = head->index + tail; | |
2518 | ||
605ca5ed | 2519 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2520 | smp_wmb(); |
2521 | ||
605ca5ed KK |
2522 | /* |
2523 | * Clear PageTail before unfreezing page refcount. | |
2524 | * | |
2525 | * After successful get_page_unless_zero() might follow put_page() | |
2526 | * which needs correct compound_head(). | |
2527 | */ | |
e9b61f19 KS |
2528 | clear_compound_head(page_tail); |
2529 | ||
605ca5ed KK |
2530 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2531 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2532 | PageSwapCache(head))); | |
2533 | ||
e9b61f19 KS |
2534 | if (page_is_young(head)) |
2535 | set_page_young(page_tail); | |
2536 | if (page_is_idle(head)) | |
2537 | set_page_idle(page_tail); | |
2538 | ||
e9b61f19 | 2539 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2540 | |
2541 | /* | |
2542 | * always add to the tail because some iterators expect new | |
2543 | * pages to show after the currently processed elements - e.g. | |
2544 | * migrate_pages | |
2545 | */ | |
e9b61f19 | 2546 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2547 | } |
2548 | ||
baa355fd | 2549 | static void __split_huge_page(struct page *page, struct list_head *list, |
006d3ff2 | 2550 | pgoff_t end, unsigned long flags) |
e9b61f19 KS |
2551 | { |
2552 | struct page *head = compound_head(page); | |
f4b7e272 | 2553 | pg_data_t *pgdat = page_pgdat(head); |
e9b61f19 | 2554 | struct lruvec *lruvec; |
4101196b MWO |
2555 | struct address_space *swap_cache = NULL; |
2556 | unsigned long offset = 0; | |
8df651c7 | 2557 | int i; |
e9b61f19 | 2558 | |
f4b7e272 | 2559 | lruvec = mem_cgroup_page_lruvec(head, pgdat); |
e9b61f19 KS |
2560 | |
2561 | /* complete memcg works before add pages to LRU */ | |
2562 | mem_cgroup_split_huge_fixup(head); | |
2563 | ||
4101196b MWO |
2564 | if (PageAnon(head) && PageSwapCache(head)) { |
2565 | swp_entry_t entry = { .val = page_private(head) }; | |
2566 | ||
2567 | offset = swp_offset(entry); | |
2568 | swap_cache = swap_address_space(entry); | |
2569 | xa_lock(&swap_cache->i_pages); | |
2570 | } | |
2571 | ||
baa355fd | 2572 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
8df651c7 | 2573 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2574 | /* Some pages can be beyond i_size: drop them from page cache */ |
2575 | if (head[i].index >= end) { | |
2d077d4b | 2576 | ClearPageDirty(head + i); |
baa355fd | 2577 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2578 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2579 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd | 2580 | put_page(head + i); |
4101196b MWO |
2581 | } else if (!PageAnon(page)) { |
2582 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2583 | head + i, 0); | |
2584 | } else if (swap_cache) { | |
2585 | __xa_store(&swap_cache->i_pages, offset + i, | |
2586 | head + i, 0); | |
baa355fd KS |
2587 | } |
2588 | } | |
e9b61f19 KS |
2589 | |
2590 | ClearPageCompound(head); | |
f7da677b | 2591 | |
a27180e4 | 2592 | split_page_owner(head, HPAGE_PMD_NR); |
f7da677b | 2593 | |
baa355fd KS |
2594 | /* See comment in __split_huge_page_tail() */ |
2595 | if (PageAnon(head)) { | |
aa5dc07f | 2596 | /* Additional pin to swap cache */ |
4101196b | 2597 | if (PageSwapCache(head)) { |
38d8b4e6 | 2598 | page_ref_add(head, 2); |
4101196b MWO |
2599 | xa_unlock(&swap_cache->i_pages); |
2600 | } else { | |
38d8b4e6 | 2601 | page_ref_inc(head); |
4101196b | 2602 | } |
baa355fd | 2603 | } else { |
aa5dc07f | 2604 | /* Additional pin to page cache */ |
baa355fd | 2605 | page_ref_add(head, 2); |
b93b0163 | 2606 | xa_unlock(&head->mapping->i_pages); |
baa355fd KS |
2607 | } |
2608 | ||
f4b7e272 | 2609 | spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
e9b61f19 | 2610 | |
906f9cdf | 2611 | remap_page(head); |
e9b61f19 KS |
2612 | |
2613 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2614 | struct page *subpage = head + i; | |
2615 | if (subpage == page) | |
2616 | continue; | |
2617 | unlock_page(subpage); | |
2618 | ||
2619 | /* | |
2620 | * Subpages may be freed if there wasn't any mapping | |
2621 | * like if add_to_swap() is running on a lru page that | |
2622 | * had its mapping zapped. And freeing these pages | |
2623 | * requires taking the lru_lock so we do the put_page | |
2624 | * of the tail pages after the split is complete. | |
2625 | */ | |
2626 | put_page(subpage); | |
2627 | } | |
2628 | } | |
2629 | ||
b20ce5e0 KS |
2630 | int total_mapcount(struct page *page) |
2631 | { | |
dd78fedd | 2632 | int i, compound, ret; |
b20ce5e0 KS |
2633 | |
2634 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2635 | ||
2636 | if (likely(!PageCompound(page))) | |
2637 | return atomic_read(&page->_mapcount) + 1; | |
2638 | ||
dd78fedd | 2639 | compound = compound_mapcount(page); |
b20ce5e0 | 2640 | if (PageHuge(page)) |
dd78fedd KS |
2641 | return compound; |
2642 | ret = compound; | |
b20ce5e0 KS |
2643 | for (i = 0; i < HPAGE_PMD_NR; i++) |
2644 | ret += atomic_read(&page[i]._mapcount) + 1; | |
dd78fedd KS |
2645 | /* File pages has compound_mapcount included in _mapcount */ |
2646 | if (!PageAnon(page)) | |
2647 | return ret - compound * HPAGE_PMD_NR; | |
b20ce5e0 KS |
2648 | if (PageDoubleMap(page)) |
2649 | ret -= HPAGE_PMD_NR; | |
2650 | return ret; | |
2651 | } | |
2652 | ||
6d0a07ed AA |
2653 | /* |
2654 | * This calculates accurately how many mappings a transparent hugepage | |
2655 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2656 | * accuracy is primarily needed to know if copy-on-write faults can | |
2657 | * reuse the page and change the mapping to read-write instead of | |
2658 | * copying them. At the same time this returns the total_mapcount too. | |
2659 | * | |
2660 | * The function returns the highest mapcount any one of the subpages | |
2661 | * has. If the return value is one, even if different processes are | |
2662 | * mapping different subpages of the transparent hugepage, they can | |
2663 | * all reuse it, because each process is reusing a different subpage. | |
2664 | * | |
2665 | * The total_mapcount is instead counting all virtual mappings of the | |
2666 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2667 | * caller all mappings belong to the same "mm" and in turn the | |
2668 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2669 | * local one as no other process may be mapping any of the subpages. | |
2670 | * | |
2671 | * It would be more accurate to replace page_mapcount() with | |
2672 | * page_trans_huge_mapcount(), however we only use | |
2673 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2674 | * need full accuracy to avoid breaking page pinning, because | |
2675 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2676 | */ | |
2677 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2678 | { | |
2679 | int i, ret, _total_mapcount, mapcount; | |
2680 | ||
2681 | /* hugetlbfs shouldn't call it */ | |
2682 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2683 | ||
2684 | if (likely(!PageTransCompound(page))) { | |
2685 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2686 | if (total_mapcount) | |
2687 | *total_mapcount = mapcount; | |
2688 | return mapcount; | |
2689 | } | |
2690 | ||
2691 | page = compound_head(page); | |
2692 | ||
2693 | _total_mapcount = ret = 0; | |
2694 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2695 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
2696 | ret = max(ret, mapcount); | |
2697 | _total_mapcount += mapcount; | |
2698 | } | |
2699 | if (PageDoubleMap(page)) { | |
2700 | ret -= 1; | |
2701 | _total_mapcount -= HPAGE_PMD_NR; | |
2702 | } | |
2703 | mapcount = compound_mapcount(page); | |
2704 | ret += mapcount; | |
2705 | _total_mapcount += mapcount; | |
2706 | if (total_mapcount) | |
2707 | *total_mapcount = _total_mapcount; | |
2708 | return ret; | |
2709 | } | |
2710 | ||
b8f593cd HY |
2711 | /* Racy check whether the huge page can be split */ |
2712 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2713 | { | |
2714 | int extra_pins; | |
2715 | ||
aa5dc07f | 2716 | /* Additional pins from page cache */ |
b8f593cd HY |
2717 | if (PageAnon(page)) |
2718 | extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; | |
2719 | else | |
2720 | extra_pins = HPAGE_PMD_NR; | |
2721 | if (pextra_pins) | |
2722 | *pextra_pins = extra_pins; | |
2723 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2724 | } | |
2725 | ||
e9b61f19 KS |
2726 | /* |
2727 | * This function splits huge page into normal pages. @page can point to any | |
2728 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2729 | * | |
2730 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2731 | * The huge page must be locked. | |
2732 | * | |
2733 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2734 | * | |
2735 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2736 | * the hugepage. | |
2737 | * | |
2738 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2739 | * they are not mapped. | |
2740 | * | |
2741 | * Returns 0 if the hugepage is split successfully. | |
2742 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2743 | * us. | |
2744 | */ | |
2745 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2746 | { | |
2747 | struct page *head = compound_head(page); | |
a3d0a918 | 2748 | struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); |
87eaceb3 | 2749 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
baa355fd KS |
2750 | struct anon_vma *anon_vma = NULL; |
2751 | struct address_space *mapping = NULL; | |
a004628d | 2752 | int extra_pins, ret; |
d9654322 | 2753 | bool mlocked; |
0b9b6fff | 2754 | unsigned long flags; |
006d3ff2 | 2755 | pgoff_t end; |
e9b61f19 | 2756 | |
d50c7e25 | 2757 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
e9b61f19 | 2758 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
e9b61f19 KS |
2759 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
2760 | ||
59807685 HY |
2761 | if (PageWriteback(page)) |
2762 | return -EBUSY; | |
2763 | ||
baa355fd KS |
2764 | if (PageAnon(head)) { |
2765 | /* | |
2766 | * The caller does not necessarily hold an mmap_sem that would | |
2767 | * prevent the anon_vma disappearing so we first we take a | |
2768 | * reference to it and then lock the anon_vma for write. This | |
2769 | * is similar to page_lock_anon_vma_read except the write lock | |
2770 | * is taken to serialise against parallel split or collapse | |
2771 | * operations. | |
2772 | */ | |
2773 | anon_vma = page_get_anon_vma(head); | |
2774 | if (!anon_vma) { | |
2775 | ret = -EBUSY; | |
2776 | goto out; | |
2777 | } | |
006d3ff2 | 2778 | end = -1; |
baa355fd KS |
2779 | mapping = NULL; |
2780 | anon_vma_lock_write(anon_vma); | |
2781 | } else { | |
2782 | mapping = head->mapping; | |
2783 | ||
2784 | /* Truncated ? */ | |
2785 | if (!mapping) { | |
2786 | ret = -EBUSY; | |
2787 | goto out; | |
2788 | } | |
2789 | ||
baa355fd KS |
2790 | anon_vma = NULL; |
2791 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2792 | |
2793 | /* | |
2794 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2795 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2796 | * which cannot be nested inside the page tree lock. So note | |
2797 | * end now: i_size itself may be changed at any moment, but | |
2798 | * head page lock is good enough to serialize the trimming. | |
2799 | */ | |
2800 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2801 | } |
e9b61f19 KS |
2802 | |
2803 | /* | |
906f9cdf | 2804 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2805 | * split PMDs |
2806 | */ | |
b8f593cd | 2807 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2808 | ret = -EBUSY; |
2809 | goto out_unlock; | |
2810 | } | |
2811 | ||
d9654322 | 2812 | mlocked = PageMlocked(page); |
906f9cdf | 2813 | unmap_page(head); |
e9b61f19 | 2814 | |
d9654322 KS |
2815 | /* Make sure the page is not on per-CPU pagevec as it takes pin */ |
2816 | if (mlocked) | |
2817 | lru_add_drain(); | |
2818 | ||
baa355fd | 2819 | /* prevent PageLRU to go away from under us, and freeze lru stats */ |
f4b7e272 | 2820 | spin_lock_irqsave(&pgdata->lru_lock, flags); |
baa355fd KS |
2821 | |
2822 | if (mapping) { | |
aa5dc07f | 2823 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2824 | |
baa355fd | 2825 | /* |
aa5dc07f | 2826 | * Check if the head page is present in page cache. |
baa355fd KS |
2827 | * We assume all tail are present too, if head is there. |
2828 | */ | |
aa5dc07f MW |
2829 | xa_lock(&mapping->i_pages); |
2830 | if (xas_load(&xas) != head) | |
baa355fd KS |
2831 | goto fail; |
2832 | } | |
2833 | ||
0139aa7b | 2834 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2835 | spin_lock(&ds_queue->split_queue_lock); |
a004628d | 2836 | if (page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2837 | if (!list_empty(page_deferred_list(head))) { |
364c1eeb | 2838 | ds_queue->split_queue_len--; |
9a982250 KS |
2839 | list_del(page_deferred_list(head)); |
2840 | } | |
06d3eff6 KS |
2841 | if (mapping) { |
2842 | if (PageSwapBacked(page)) | |
2843 | __dec_node_page_state(page, NR_SHMEM_THPS); | |
2844 | else | |
2845 | __dec_node_page_state(page, NR_FILE_THPS); | |
2846 | } | |
2847 | ||
364c1eeb | 2848 | spin_unlock(&ds_queue->split_queue_lock); |
006d3ff2 | 2849 | __split_huge_page(page, list, end, flags); |
59807685 HY |
2850 | if (PageSwapCache(head)) { |
2851 | swp_entry_t entry = { .val = page_private(head) }; | |
2852 | ||
2853 | ret = split_swap_cluster(entry); | |
2854 | } else | |
2855 | ret = 0; | |
e9b61f19 | 2856 | } else { |
364c1eeb | 2857 | spin_unlock(&ds_queue->split_queue_lock); |
a004628d YS |
2858 | fail: |
2859 | if (mapping) | |
b93b0163 | 2860 | xa_unlock(&mapping->i_pages); |
f4b7e272 | 2861 | spin_unlock_irqrestore(&pgdata->lru_lock, flags); |
906f9cdf | 2862 | remap_page(head); |
e9b61f19 KS |
2863 | ret = -EBUSY; |
2864 | } | |
2865 | ||
2866 | out_unlock: | |
baa355fd KS |
2867 | if (anon_vma) { |
2868 | anon_vma_unlock_write(anon_vma); | |
2869 | put_anon_vma(anon_vma); | |
2870 | } | |
2871 | if (mapping) | |
2872 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2873 | out: |
2874 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2875 | return ret; | |
2876 | } | |
9a982250 KS |
2877 | |
2878 | void free_transhuge_page(struct page *page) | |
2879 | { | |
87eaceb3 | 2880 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2881 | unsigned long flags; |
2882 | ||
364c1eeb | 2883 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2884 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2885 | ds_queue->split_queue_len--; |
9a982250 KS |
2886 | list_del(page_deferred_list(page)); |
2887 | } | |
364c1eeb | 2888 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2889 | free_compound_page(page); |
2890 | } | |
2891 | ||
2892 | void deferred_split_huge_page(struct page *page) | |
2893 | { | |
87eaceb3 YS |
2894 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2895 | #ifdef CONFIG_MEMCG | |
2896 | struct mem_cgroup *memcg = compound_head(page)->mem_cgroup; | |
2897 | #endif | |
9a982250 KS |
2898 | unsigned long flags; |
2899 | ||
2900 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2901 | ||
87eaceb3 YS |
2902 | /* |
2903 | * The try_to_unmap() in page reclaim path might reach here too, | |
2904 | * this may cause a race condition to corrupt deferred split queue. | |
2905 | * And, if page reclaim is already handling the same page, it is | |
2906 | * unnecessary to handle it again in shrinker. | |
2907 | * | |
2908 | * Check PageSwapCache to determine if the page is being | |
2909 | * handled by page reclaim since THP swap would add the page into | |
2910 | * swap cache before calling try_to_unmap(). | |
2911 | */ | |
2912 | if (PageSwapCache(page)) | |
2913 | return; | |
2914 | ||
364c1eeb | 2915 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2916 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2917 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2918 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2919 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2920 | #ifdef CONFIG_MEMCG |
2921 | if (memcg) | |
2922 | memcg_set_shrinker_bit(memcg, page_to_nid(page), | |
2923 | deferred_split_shrinker.id); | |
2924 | #endif | |
9a982250 | 2925 | } |
364c1eeb | 2926 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2927 | } |
2928 | ||
2929 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2930 | struct shrink_control *sc) | |
2931 | { | |
a3d0a918 | 2932 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2933 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2934 | |
2935 | #ifdef CONFIG_MEMCG | |
2936 | if (sc->memcg) | |
2937 | ds_queue = &sc->memcg->deferred_split_queue; | |
2938 | #endif | |
364c1eeb | 2939 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2940 | } |
2941 | ||
2942 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2943 | struct shrink_control *sc) | |
2944 | { | |
a3d0a918 | 2945 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2946 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2947 | unsigned long flags; |
2948 | LIST_HEAD(list), *pos, *next; | |
2949 | struct page *page; | |
2950 | int split = 0; | |
2951 | ||
87eaceb3 YS |
2952 | #ifdef CONFIG_MEMCG |
2953 | if (sc->memcg) | |
2954 | ds_queue = &sc->memcg->deferred_split_queue; | |
2955 | #endif | |
2956 | ||
364c1eeb | 2957 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2958 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2959 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
9a982250 KS |
2960 | page = list_entry((void *)pos, struct page, mapping); |
2961 | page = compound_head(page); | |
e3ae1953 KS |
2962 | if (get_page_unless_zero(page)) { |
2963 | list_move(page_deferred_list(page), &list); | |
2964 | } else { | |
2965 | /* We lost race with put_compound_page() */ | |
9a982250 | 2966 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2967 | ds_queue->split_queue_len--; |
9a982250 | 2968 | } |
e3ae1953 KS |
2969 | if (!--sc->nr_to_scan) |
2970 | break; | |
9a982250 | 2971 | } |
364c1eeb | 2972 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2973 | |
2974 | list_for_each_safe(pos, next, &list) { | |
2975 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2976 | if (!trylock_page(page)) |
2977 | goto next; | |
9a982250 KS |
2978 | /* split_huge_page() removes page from list on success */ |
2979 | if (!split_huge_page(page)) | |
2980 | split++; | |
2981 | unlock_page(page); | |
fa41b900 | 2982 | next: |
9a982250 KS |
2983 | put_page(page); |
2984 | } | |
2985 | ||
364c1eeb YS |
2986 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2987 | list_splice_tail(&list, &ds_queue->split_queue); | |
2988 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2989 | |
cb8d68ec KS |
2990 | /* |
2991 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2992 | * This can happen if pages were freed under us. | |
2993 | */ | |
364c1eeb | 2994 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2995 | return SHRINK_STOP; |
2996 | return split; | |
9a982250 KS |
2997 | } |
2998 | ||
2999 | static struct shrinker deferred_split_shrinker = { | |
3000 | .count_objects = deferred_split_count, | |
3001 | .scan_objects = deferred_split_scan, | |
3002 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
3003 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
3004 | SHRINKER_NONSLAB, | |
9a982250 | 3005 | }; |
49071d43 KS |
3006 | |
3007 | #ifdef CONFIG_DEBUG_FS | |
3008 | static int split_huge_pages_set(void *data, u64 val) | |
3009 | { | |
3010 | struct zone *zone; | |
3011 | struct page *page; | |
3012 | unsigned long pfn, max_zone_pfn; | |
3013 | unsigned long total = 0, split = 0; | |
3014 | ||
3015 | if (val != 1) | |
3016 | return -EINVAL; | |
3017 | ||
3018 | for_each_populated_zone(zone) { | |
3019 | max_zone_pfn = zone_end_pfn(zone); | |
3020 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
3021 | if (!pfn_valid(pfn)) | |
3022 | continue; | |
3023 | ||
3024 | page = pfn_to_page(pfn); | |
3025 | if (!get_page_unless_zero(page)) | |
3026 | continue; | |
3027 | ||
3028 | if (zone != page_zone(page)) | |
3029 | goto next; | |
3030 | ||
baa355fd | 3031 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
3032 | goto next; |
3033 | ||
3034 | total++; | |
3035 | lock_page(page); | |
3036 | if (!split_huge_page(page)) | |
3037 | split++; | |
3038 | unlock_page(page); | |
3039 | next: | |
3040 | put_page(page); | |
3041 | } | |
3042 | } | |
3043 | ||
145bdaa1 | 3044 | pr_info("%lu of %lu THP split\n", split, total); |
49071d43 KS |
3045 | |
3046 | return 0; | |
3047 | } | |
3048 | DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, | |
3049 | "%llu\n"); | |
3050 | ||
3051 | static int __init split_huge_pages_debugfs(void) | |
3052 | { | |
d9f7979c GKH |
3053 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3054 | &split_huge_pages_fops); | |
49071d43 KS |
3055 | return 0; |
3056 | } | |
3057 | late_initcall(split_huge_pages_debugfs); | |
3058 | #endif | |
616b8371 ZY |
3059 | |
3060 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
3061 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
3062 | struct page *page) | |
3063 | { | |
3064 | struct vm_area_struct *vma = pvmw->vma; | |
3065 | struct mm_struct *mm = vma->vm_mm; | |
3066 | unsigned long address = pvmw->address; | |
3067 | pmd_t pmdval; | |
3068 | swp_entry_t entry; | |
ab6e3d09 | 3069 | pmd_t pmdswp; |
616b8371 ZY |
3070 | |
3071 | if (!(pvmw->pmd && !pvmw->pte)) | |
3072 | return; | |
3073 | ||
616b8371 | 3074 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
db25db7b | 3075 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
616b8371 ZY |
3076 | if (pmd_dirty(pmdval)) |
3077 | set_page_dirty(page); | |
3078 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
3079 | pmdswp = swp_entry_to_pmd(entry); |
3080 | if (pmd_soft_dirty(pmdval)) | |
3081 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3082 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
3083 | page_remove_rmap(page, true); |
3084 | put_page(page); | |
616b8371 ZY |
3085 | } |
3086 | ||
3087 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3088 | { | |
3089 | struct vm_area_struct *vma = pvmw->vma; | |
3090 | struct mm_struct *mm = vma->vm_mm; | |
3091 | unsigned long address = pvmw->address; | |
3092 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
3093 | pmd_t pmde; | |
3094 | swp_entry_t entry; | |
3095 | ||
3096 | if (!(pvmw->pmd && !pvmw->pte)) | |
3097 | return; | |
3098 | ||
3099 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3100 | get_page(new); | |
3101 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
3102 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3103 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 3104 | if (is_write_migration_entry(entry)) |
f55e1014 | 3105 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
3106 | |
3107 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
3108 | if (PageAnon(new)) |
3109 | page_add_anon_rmap(new, vma, mmun_start, true); | |
3110 | else | |
3111 | page_add_file_rmap(new, true); | |
616b8371 | 3112 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 3113 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
3114 | mlock_vma_page(new); |
3115 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
3116 | } | |
3117 | #endif |