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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> | |
fa6c0231 | 10 | #include <linux/sched/mm.h> |
f7ccbae4 | 11 | #include <linux/sched/coredump.h> |
6a3827d7 | 12 | #include <linux/sched/numa_balancing.h> |
71e3aac0 AA |
13 | #include <linux/highmem.h> |
14 | #include <linux/hugetlb.h> | |
15 | #include <linux/mmu_notifier.h> | |
16 | #include <linux/rmap.h> | |
17 | #include <linux/swap.h> | |
97ae1749 | 18 | #include <linux/shrinker.h> |
ba76149f | 19 | #include <linux/mm_inline.h> |
e9b61f19 | 20 | #include <linux/swapops.h> |
4897c765 | 21 | #include <linux/dax.h> |
ba76149f | 22 | #include <linux/khugepaged.h> |
878aee7d | 23 | #include <linux/freezer.h> |
f25748e3 | 24 | #include <linux/pfn_t.h> |
a664b2d8 | 25 | #include <linux/mman.h> |
3565fce3 | 26 | #include <linux/memremap.h> |
325adeb5 | 27 | #include <linux/pagemap.h> |
49071d43 | 28 | #include <linux/debugfs.h> |
4daae3b4 | 29 | #include <linux/migrate.h> |
43b5fbbd | 30 | #include <linux/hashtable.h> |
6b251fc9 | 31 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 32 | #include <linux/page_idle.h> |
baa355fd | 33 | #include <linux/shmem_fs.h> |
6b31d595 | 34 | #include <linux/oom.h> |
98fa15f3 | 35 | #include <linux/numa.h> |
f7da677b | 36 | #include <linux/page_owner.h> |
97ae1749 | 37 | |
71e3aac0 AA |
38 | #include <asm/tlb.h> |
39 | #include <asm/pgalloc.h> | |
40 | #include "internal.h" | |
41 | ||
ba76149f | 42 | /* |
b14d595a MD |
43 | * By default, transparent hugepage support is disabled in order to avoid |
44 | * risking an increased memory footprint for applications that are not | |
45 | * guaranteed to benefit from it. When transparent hugepage support is | |
46 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
47 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
48 | * for all hugepage allocations. | |
ba76149f | 49 | */ |
71e3aac0 | 50 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 51 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 52 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
53 | #endif |
54 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
55 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
56 | #endif | |
444eb2a4 | 57 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
58 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
59 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 60 | |
9a982250 | 61 | static struct shrinker deferred_split_shrinker; |
f000565a | 62 | |
97ae1749 | 63 | static atomic_t huge_zero_refcount; |
56873f43 | 64 | struct page *huge_zero_page __read_mostly; |
4a6c1297 | 65 | |
7635d9cb MH |
66 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
67 | { | |
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 | ||
aaa9705b | 81 | static bool 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))) | |
aaa9705b | 86 | return true; |
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); | |
aaa9705b | 92 | return false; |
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 | } | |
101 | ||
102 | /* We take additional reference here. It will be put back by shrinker */ | |
103 | atomic_set(&huge_zero_refcount, 2); | |
104 | preempt_enable(); | |
aaa9705b | 105 | return true; |
4a6c1297 KS |
106 | } |
107 | ||
6fcb52a5 | 108 | static void put_huge_zero_page(void) |
4a6c1297 | 109 | { |
97ae1749 KS |
110 | /* |
111 | * Counter should never go to zero here. Only shrinker can put | |
112 | * last reference. | |
113 | */ | |
114 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
115 | } |
116 | ||
6fcb52a5 AL |
117 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
118 | { | |
119 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
120 | return READ_ONCE(huge_zero_page); | |
121 | ||
122 | if (!get_huge_zero_page()) | |
123 | return NULL; | |
124 | ||
125 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
126 | put_huge_zero_page(); | |
127 | ||
128 | return READ_ONCE(huge_zero_page); | |
129 | } | |
130 | ||
131 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
132 | { | |
133 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
134 | put_huge_zero_page(); | |
135 | } | |
136 | ||
48896466 GC |
137 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
138 | struct shrink_control *sc) | |
4a6c1297 | 139 | { |
48896466 GC |
140 | /* we can free zero page only if last reference remains */ |
141 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
142 | } | |
97ae1749 | 143 | |
48896466 GC |
144 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
145 | struct shrink_control *sc) | |
146 | { | |
97ae1749 | 147 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
148 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
149 | BUG_ON(zero_page == NULL); | |
5ddacbe9 | 150 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 151 | return HPAGE_PMD_NR; |
97ae1749 KS |
152 | } |
153 | ||
154 | return 0; | |
4a6c1297 KS |
155 | } |
156 | ||
97ae1749 | 157 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
158 | .count_objects = shrink_huge_zero_page_count, |
159 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
160 | .seeks = DEFAULT_SEEKS, |
161 | }; | |
162 | ||
71e3aac0 | 163 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
164 | static ssize_t enabled_show(struct kobject *kobj, |
165 | struct kobj_attribute *attr, char *buf) | |
166 | { | |
bfb0ffeb JP |
167 | const char *output; |
168 | ||
444eb2a4 | 169 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
170 | output = "[always] madvise never"; |
171 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
172 | &transparent_hugepage_flags)) | |
173 | output = "always [madvise] never"; | |
444eb2a4 | 174 | else |
bfb0ffeb JP |
175 | output = "always madvise [never]"; |
176 | ||
177 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 178 | } |
444eb2a4 | 179 | |
71e3aac0 AA |
180 | static ssize_t enabled_store(struct kobject *kobj, |
181 | struct kobj_attribute *attr, | |
182 | const char *buf, size_t count) | |
183 | { | |
21440d7e | 184 | ssize_t ret = count; |
ba76149f | 185 | |
f42f2552 | 186 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
187 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
188 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 189 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
190 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
191 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 192 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
193 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
194 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
195 | } else | |
196 | ret = -EINVAL; | |
ba76149f AA |
197 | |
198 | if (ret > 0) { | |
b46e756f | 199 | int err = start_stop_khugepaged(); |
ba76149f AA |
200 | if (err) |
201 | ret = err; | |
202 | } | |
ba76149f | 203 | return ret; |
71e3aac0 AA |
204 | } |
205 | static struct kobj_attribute enabled_attr = | |
206 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
207 | ||
b46e756f | 208 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
209 | struct kobj_attribute *attr, char *buf, |
210 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 211 | { |
bfb0ffeb JP |
212 | return sysfs_emit(buf, "%d\n", |
213 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 214 | } |
e27e6151 | 215 | |
b46e756f | 216 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
217 | struct kobj_attribute *attr, |
218 | const char *buf, size_t count, | |
219 | enum transparent_hugepage_flag flag) | |
220 | { | |
e27e6151 BH |
221 | unsigned long value; |
222 | int ret; | |
223 | ||
224 | ret = kstrtoul(buf, 10, &value); | |
225 | if (ret < 0) | |
226 | return ret; | |
227 | if (value > 1) | |
228 | return -EINVAL; | |
229 | ||
230 | if (value) | |
71e3aac0 | 231 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 232 | else |
71e3aac0 | 233 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
234 | |
235 | return count; | |
236 | } | |
237 | ||
71e3aac0 AA |
238 | static ssize_t defrag_show(struct kobject *kobj, |
239 | struct kobj_attribute *attr, char *buf) | |
240 | { | |
bfb0ffeb JP |
241 | const char *output; |
242 | ||
243 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
244 | &transparent_hugepage_flags)) | |
245 | output = "[always] defer defer+madvise madvise never"; | |
246 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
247 | &transparent_hugepage_flags)) | |
248 | output = "always [defer] defer+madvise madvise never"; | |
249 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
250 | &transparent_hugepage_flags)) | |
251 | output = "always defer [defer+madvise] madvise never"; | |
252 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
253 | &transparent_hugepage_flags)) | |
254 | output = "always defer defer+madvise [madvise] never"; | |
255 | else | |
256 | output = "always defer defer+madvise madvise [never]"; | |
257 | ||
258 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 259 | } |
21440d7e | 260 | |
71e3aac0 AA |
261 | static ssize_t defrag_store(struct kobject *kobj, |
262 | struct kobj_attribute *attr, | |
263 | const char *buf, size_t count) | |
264 | { | |
f42f2552 | 265 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
266 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
267 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
268 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
269 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 270 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
271 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
272 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
273 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
274 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 275 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
276 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
277 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
278 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
279 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 280 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
281 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
282 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
283 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
284 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 285 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
286 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
287 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
288 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
289 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
290 | } else | |
291 | return -EINVAL; | |
292 | ||
293 | return count; | |
71e3aac0 AA |
294 | } |
295 | static struct kobj_attribute defrag_attr = | |
296 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
297 | ||
79da5407 | 298 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 299 | struct kobj_attribute *attr, char *buf) |
79da5407 | 300 | { |
b46e756f | 301 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 302 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
303 | } |
304 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
305 | struct kobj_attribute *attr, const char *buf, size_t count) | |
306 | { | |
b46e756f | 307 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
308 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
309 | } | |
310 | static struct kobj_attribute use_zero_page_attr = | |
311 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
312 | |
313 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 314 | struct kobj_attribute *attr, char *buf) |
49920d28 | 315 | { |
ae7a927d | 316 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
317 | } |
318 | static struct kobj_attribute hpage_pmd_size_attr = | |
319 | __ATTR_RO(hpage_pmd_size); | |
320 | ||
71e3aac0 AA |
321 | static struct attribute *hugepage_attr[] = { |
322 | &enabled_attr.attr, | |
323 | &defrag_attr.attr, | |
79da5407 | 324 | &use_zero_page_attr.attr, |
49920d28 | 325 | &hpage_pmd_size_attr.attr, |
396bcc52 | 326 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 327 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
328 | #endif |
329 | NULL, | |
330 | }; | |
331 | ||
8aa95a21 | 332 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 333 | .attrs = hugepage_attr, |
ba76149f AA |
334 | }; |
335 | ||
569e5590 | 336 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 337 | { |
71e3aac0 AA |
338 | int err; |
339 | ||
569e5590 SL |
340 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
341 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 342 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 343 | return -ENOMEM; |
ba76149f AA |
344 | } |
345 | ||
569e5590 | 346 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 347 | if (err) { |
ae3a8c1c | 348 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 349 | goto delete_obj; |
ba76149f AA |
350 | } |
351 | ||
569e5590 | 352 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 353 | if (err) { |
ae3a8c1c | 354 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 355 | goto remove_hp_group; |
ba76149f | 356 | } |
569e5590 SL |
357 | |
358 | return 0; | |
359 | ||
360 | remove_hp_group: | |
361 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
362 | delete_obj: | |
363 | kobject_put(*hugepage_kobj); | |
364 | return err; | |
365 | } | |
366 | ||
367 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
368 | { | |
369 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
370 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
371 | kobject_put(hugepage_kobj); | |
372 | } | |
373 | #else | |
374 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
375 | { | |
376 | return 0; | |
377 | } | |
378 | ||
379 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
380 | { | |
381 | } | |
382 | #endif /* CONFIG_SYSFS */ | |
383 | ||
384 | static int __init hugepage_init(void) | |
385 | { | |
386 | int err; | |
387 | struct kobject *hugepage_kobj; | |
388 | ||
389 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
390 | /* |
391 | * Hardware doesn't support hugepages, hence disable | |
392 | * DAX PMD support. | |
393 | */ | |
394 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
395 | return -EINVAL; |
396 | } | |
397 | ||
ff20c2e0 KS |
398 | /* |
399 | * hugepages can't be allocated by the buddy allocator | |
400 | */ | |
401 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
402 | /* | |
403 | * we use page->mapping and page->index in second tail page | |
404 | * as list_head: assuming THP order >= 2 | |
405 | */ | |
406 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
407 | ||
569e5590 SL |
408 | err = hugepage_init_sysfs(&hugepage_kobj); |
409 | if (err) | |
65ebb64f | 410 | goto err_sysfs; |
ba76149f | 411 | |
b46e756f | 412 | err = khugepaged_init(); |
ba76149f | 413 | if (err) |
65ebb64f | 414 | goto err_slab; |
ba76149f | 415 | |
65ebb64f KS |
416 | err = register_shrinker(&huge_zero_page_shrinker); |
417 | if (err) | |
418 | goto err_hzp_shrinker; | |
9a982250 KS |
419 | err = register_shrinker(&deferred_split_shrinker); |
420 | if (err) | |
421 | goto err_split_shrinker; | |
97ae1749 | 422 | |
97562cd2 RR |
423 | /* |
424 | * By default disable transparent hugepages on smaller systems, | |
425 | * where the extra memory used could hurt more than TLB overhead | |
426 | * is likely to save. The admin can still enable it through /sys. | |
427 | */ | |
ca79b0c2 | 428 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 429 | transparent_hugepage_flags = 0; |
79553da2 KS |
430 | return 0; |
431 | } | |
97562cd2 | 432 | |
79553da2 | 433 | err = start_stop_khugepaged(); |
65ebb64f KS |
434 | if (err) |
435 | goto err_khugepaged; | |
ba76149f | 436 | |
569e5590 | 437 | return 0; |
65ebb64f | 438 | err_khugepaged: |
9a982250 KS |
439 | unregister_shrinker(&deferred_split_shrinker); |
440 | err_split_shrinker: | |
65ebb64f KS |
441 | unregister_shrinker(&huge_zero_page_shrinker); |
442 | err_hzp_shrinker: | |
b46e756f | 443 | khugepaged_destroy(); |
65ebb64f | 444 | err_slab: |
569e5590 | 445 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 446 | err_sysfs: |
ba76149f | 447 | return err; |
71e3aac0 | 448 | } |
a64fb3cd | 449 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
450 | |
451 | static int __init setup_transparent_hugepage(char *str) | |
452 | { | |
453 | int ret = 0; | |
454 | if (!str) | |
455 | goto out; | |
456 | if (!strcmp(str, "always")) { | |
457 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
458 | &transparent_hugepage_flags); | |
459 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
460 | &transparent_hugepage_flags); | |
461 | ret = 1; | |
462 | } else if (!strcmp(str, "madvise")) { | |
463 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
464 | &transparent_hugepage_flags); | |
465 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
466 | &transparent_hugepage_flags); | |
467 | ret = 1; | |
468 | } else if (!strcmp(str, "never")) { | |
469 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
470 | &transparent_hugepage_flags); | |
471 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
472 | &transparent_hugepage_flags); | |
473 | ret = 1; | |
474 | } | |
475 | out: | |
476 | if (!ret) | |
ae3a8c1c | 477 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
478 | return ret; |
479 | } | |
480 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
481 | ||
f55e1014 | 482 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 483 | { |
f55e1014 | 484 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
485 | pmd = pmd_mkwrite(pmd); |
486 | return pmd; | |
487 | } | |
488 | ||
87eaceb3 YS |
489 | #ifdef CONFIG_MEMCG |
490 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 491 | { |
bcfe06bf | 492 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 YS |
493 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); |
494 | ||
495 | if (memcg) | |
496 | return &memcg->deferred_split_queue; | |
497 | else | |
498 | return &pgdat->deferred_split_queue; | |
9a982250 | 499 | } |
87eaceb3 YS |
500 | #else |
501 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
502 | { | |
503 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
504 | ||
505 | return &pgdat->deferred_split_queue; | |
506 | } | |
507 | #endif | |
9a982250 KS |
508 | |
509 | void prep_transhuge_page(struct page *page) | |
510 | { | |
511 | /* | |
512 | * we use page->mapping and page->indexlru in second tail page | |
513 | * as list_head: assuming THP order >= 2 | |
514 | */ | |
9a982250 KS |
515 | |
516 | INIT_LIST_HEAD(page_deferred_list(page)); | |
517 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
518 | } | |
519 | ||
005ba37c SC |
520 | bool is_transparent_hugepage(struct page *page) |
521 | { | |
522 | if (!PageCompound(page)) | |
fa1f68cc | 523 | return false; |
005ba37c SC |
524 | |
525 | page = compound_head(page); | |
526 | return is_huge_zero_page(page) || | |
527 | page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; | |
528 | } | |
529 | EXPORT_SYMBOL_GPL(is_transparent_hugepage); | |
530 | ||
97d3d0f9 KS |
531 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
532 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
533 | loff_t off, unsigned long flags, unsigned long size) |
534 | { | |
74d2fad1 TK |
535 | loff_t off_end = off + len; |
536 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 537 | unsigned long len_pad, ret; |
74d2fad1 TK |
538 | |
539 | if (off_end <= off_align || (off_end - off_align) < size) | |
540 | return 0; | |
541 | ||
542 | len_pad = len + size; | |
543 | if (len_pad < len || (off + len_pad) < off) | |
544 | return 0; | |
545 | ||
97d3d0f9 | 546 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 547 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
548 | |
549 | /* | |
550 | * The failure might be due to length padding. The caller will retry | |
551 | * without the padding. | |
552 | */ | |
553 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
554 | return 0; |
555 | ||
97d3d0f9 KS |
556 | /* |
557 | * Do not try to align to THP boundary if allocation at the address | |
558 | * hint succeeds. | |
559 | */ | |
560 | if (ret == addr) | |
561 | return addr; | |
562 | ||
563 | ret += (off - ret) & (size - 1); | |
564 | return ret; | |
74d2fad1 TK |
565 | } |
566 | ||
567 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
568 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
569 | { | |
97d3d0f9 | 570 | unsigned long ret; |
74d2fad1 TK |
571 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
572 | ||
74d2fad1 TK |
573 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) |
574 | goto out; | |
575 | ||
97d3d0f9 KS |
576 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
577 | if (ret) | |
578 | return ret; | |
579 | out: | |
74d2fad1 TK |
580 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
581 | } | |
582 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
583 | ||
2b740303 SJ |
584 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
585 | struct page *page, gfp_t gfp) | |
71e3aac0 | 586 | { |
82b0f8c3 | 587 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 588 | pgtable_t pgtable; |
82b0f8c3 | 589 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 590 | vm_fault_t ret = 0; |
71e3aac0 | 591 | |
309381fe | 592 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 593 | |
d9eb1ea2 | 594 | if (mem_cgroup_charge(page, vma->vm_mm, gfp)) { |
6b251fc9 AA |
595 | put_page(page); |
596 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 597 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
598 | return VM_FAULT_FALLBACK; |
599 | } | |
9d82c694 | 600 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 601 | |
4cf58924 | 602 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 603 | if (unlikely(!pgtable)) { |
6b31d595 MH |
604 | ret = VM_FAULT_OOM; |
605 | goto release; | |
00501b53 | 606 | } |
71e3aac0 | 607 | |
c79b57e4 | 608 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
609 | /* |
610 | * The memory barrier inside __SetPageUptodate makes sure that | |
611 | * clear_huge_page writes become visible before the set_pmd_at() | |
612 | * write. | |
613 | */ | |
71e3aac0 AA |
614 | __SetPageUptodate(page); |
615 | ||
82b0f8c3 JK |
616 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
617 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 618 | goto unlock_release; |
71e3aac0 AA |
619 | } else { |
620 | pmd_t entry; | |
6b251fc9 | 621 | |
6b31d595 MH |
622 | ret = check_stable_address_space(vma->vm_mm); |
623 | if (ret) | |
624 | goto unlock_release; | |
625 | ||
6b251fc9 AA |
626 | /* Deliver the page fault to userland */ |
627 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 628 | spin_unlock(vmf->ptl); |
6b251fc9 | 629 | put_page(page); |
bae473a4 | 630 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
631 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
632 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
633 | return ret; | |
6b251fc9 AA |
634 | } |
635 | ||
3122359a | 636 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 637 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 638 | page_add_new_anon_rmap(page, vma, haddr, true); |
b518154e | 639 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
640 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
641 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 642 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 643 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 644 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 645 | spin_unlock(vmf->ptl); |
6b251fc9 | 646 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 647 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
648 | } |
649 | ||
aa2e878e | 650 | return 0; |
6b31d595 MH |
651 | unlock_release: |
652 | spin_unlock(vmf->ptl); | |
653 | release: | |
654 | if (pgtable) | |
655 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
656 | put_page(page); |
657 | return ret; | |
658 | ||
71e3aac0 AA |
659 | } |
660 | ||
444eb2a4 | 661 | /* |
21440d7e DR |
662 | * always: directly stall for all thp allocations |
663 | * defer: wake kswapd and fail if not immediately available | |
664 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
665 | * fail if not immediately available | |
666 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
667 | * available | |
668 | * never: never stall for any thp allocation | |
444eb2a4 | 669 | */ |
164cc4fe | 670 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 671 | { |
164cc4fe | 672 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 673 | |
ac79f78d | 674 | /* Always do synchronous compaction */ |
a8282608 AA |
675 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
676 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
677 | |
678 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 679 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 680 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
681 | |
682 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 683 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
684 | return GFP_TRANSHUGE_LIGHT | |
685 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
686 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
687 | |
688 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 689 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
690 | return GFP_TRANSHUGE_LIGHT | |
691 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 692 | |
19deb769 | 693 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
694 | } |
695 | ||
c4088ebd | 696 | /* Caller must hold page table lock. */ |
2efeb8da | 697 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 698 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 699 | struct page *zero_page) |
fc9fe822 KS |
700 | { |
701 | pmd_t entry; | |
7c414164 | 702 | if (!pmd_none(*pmd)) |
2efeb8da | 703 | return; |
5918d10a | 704 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 705 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
706 | if (pgtable) |
707 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 708 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 709 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
710 | } |
711 | ||
2b740303 | 712 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 713 | { |
82b0f8c3 | 714 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 715 | gfp_t gfp; |
71e3aac0 | 716 | struct page *page; |
82b0f8c3 | 717 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 718 | |
43675e6f | 719 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 720 | return VM_FAULT_FALLBACK; |
128ec037 KS |
721 | if (unlikely(anon_vma_prepare(vma))) |
722 | return VM_FAULT_OOM; | |
6d50e60c | 723 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 724 | return VM_FAULT_OOM; |
82b0f8c3 | 725 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 726 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
727 | transparent_hugepage_use_zero_page()) { |
728 | pgtable_t pgtable; | |
729 | struct page *zero_page; | |
2b740303 | 730 | vm_fault_t ret; |
4cf58924 | 731 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 732 | if (unlikely(!pgtable)) |
ba76149f | 733 | return VM_FAULT_OOM; |
6fcb52a5 | 734 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 735 | if (unlikely(!zero_page)) { |
bae473a4 | 736 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 737 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 738 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 739 | } |
82b0f8c3 | 740 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 741 | ret = 0; |
82b0f8c3 | 742 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
743 | ret = check_stable_address_space(vma->vm_mm); |
744 | if (ret) { | |
745 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 746 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 747 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 748 | spin_unlock(vmf->ptl); |
bfe8cc1d | 749 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 750 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
751 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
752 | } else { | |
bae473a4 | 753 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 754 | haddr, vmf->pmd, zero_page); |
fca40573 | 755 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 756 | spin_unlock(vmf->ptl); |
6b251fc9 | 757 | } |
bfe8cc1d | 758 | } else { |
82b0f8c3 | 759 | spin_unlock(vmf->ptl); |
bae473a4 | 760 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 761 | } |
6b251fc9 | 762 | return ret; |
71e3aac0 | 763 | } |
164cc4fe | 764 | gfp = vma_thp_gfp_mask(vma); |
19deb769 | 765 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
766 | if (unlikely(!page)) { |
767 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 768 | return VM_FAULT_FALLBACK; |
128ec037 | 769 | } |
9a982250 | 770 | prep_transhuge_page(page); |
82b0f8c3 | 771 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
772 | } |
773 | ||
ae18d6dc | 774 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
775 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
776 | pgtable_t pgtable) | |
5cad465d MW |
777 | { |
778 | struct mm_struct *mm = vma->vm_mm; | |
779 | pmd_t entry; | |
780 | spinlock_t *ptl; | |
781 | ||
782 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
783 | if (!pmd_none(*pmd)) { |
784 | if (write) { | |
785 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
786 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
787 | goto out_unlock; | |
788 | } | |
789 | entry = pmd_mkyoung(*pmd); | |
790 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
791 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
792 | update_mmu_cache_pmd(vma, addr, pmd); | |
793 | } | |
794 | ||
795 | goto out_unlock; | |
796 | } | |
797 | ||
f25748e3 DW |
798 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
799 | if (pfn_t_devmap(pfn)) | |
800 | entry = pmd_mkdevmap(entry); | |
01871e59 | 801 | if (write) { |
f55e1014 LT |
802 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
803 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 804 | } |
3b6521f5 OH |
805 | |
806 | if (pgtable) { | |
807 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 808 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 809 | pgtable = NULL; |
3b6521f5 OH |
810 | } |
811 | ||
01871e59 RZ |
812 | set_pmd_at(mm, addr, pmd, entry); |
813 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
814 | |
815 | out_unlock: | |
5cad465d | 816 | spin_unlock(ptl); |
c6f3c5ee AK |
817 | if (pgtable) |
818 | pte_free(mm, pgtable); | |
5cad465d MW |
819 | } |
820 | ||
9a9731b1 THV |
821 | /** |
822 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
823 | * @vmf: Structure describing the fault | |
824 | * @pfn: pfn to insert | |
825 | * @pgprot: page protection to use | |
826 | * @write: whether it's a write fault | |
827 | * | |
828 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
829 | * also consult the vmf_insert_mixed_prot() documentation when | |
830 | * @pgprot != @vmf->vma->vm_page_prot. | |
831 | * | |
832 | * Return: vm_fault_t value. | |
833 | */ | |
834 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
835 | pgprot_t pgprot, bool write) | |
5cad465d | 836 | { |
fce86ff5 DW |
837 | unsigned long addr = vmf->address & PMD_MASK; |
838 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 839 | pgtable_t pgtable = NULL; |
fce86ff5 | 840 | |
5cad465d MW |
841 | /* |
842 | * If we had pmd_special, we could avoid all these restrictions, | |
843 | * but we need to be consistent with PTEs and architectures that | |
844 | * can't support a 'special' bit. | |
845 | */ | |
e1fb4a08 DJ |
846 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
847 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
848 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
849 | (VM_PFNMAP|VM_MIXEDMAP)); | |
850 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
851 | |
852 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
853 | return VM_FAULT_SIGBUS; | |
308a047c | 854 | |
3b6521f5 | 855 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 856 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
857 | if (!pgtable) |
858 | return VM_FAULT_OOM; | |
859 | } | |
860 | ||
308a047c BP |
861 | track_pfn_insert(vma, &pgprot, pfn); |
862 | ||
fce86ff5 | 863 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 864 | return VM_FAULT_NOPAGE; |
5cad465d | 865 | } |
9a9731b1 | 866 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 867 | |
a00cc7d9 | 868 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 869 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 870 | { |
f55e1014 | 871 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
872 | pud = pud_mkwrite(pud); |
873 | return pud; | |
874 | } | |
875 | ||
876 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
877 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
878 | { | |
879 | struct mm_struct *mm = vma->vm_mm; | |
880 | pud_t entry; | |
881 | spinlock_t *ptl; | |
882 | ||
883 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
884 | if (!pud_none(*pud)) { |
885 | if (write) { | |
886 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
887 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
888 | goto out_unlock; | |
889 | } | |
890 | entry = pud_mkyoung(*pud); | |
891 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
892 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
893 | update_mmu_cache_pud(vma, addr, pud); | |
894 | } | |
895 | goto out_unlock; | |
896 | } | |
897 | ||
a00cc7d9 MW |
898 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
899 | if (pfn_t_devmap(pfn)) | |
900 | entry = pud_mkdevmap(entry); | |
901 | if (write) { | |
f55e1014 LT |
902 | entry = pud_mkyoung(pud_mkdirty(entry)); |
903 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
904 | } |
905 | set_pud_at(mm, addr, pud, entry); | |
906 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
907 | |
908 | out_unlock: | |
a00cc7d9 MW |
909 | spin_unlock(ptl); |
910 | } | |
911 | ||
9a9731b1 THV |
912 | /** |
913 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
914 | * @vmf: Structure describing the fault | |
915 | * @pfn: pfn to insert | |
916 | * @pgprot: page protection to use | |
917 | * @write: whether it's a write fault | |
918 | * | |
919 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
920 | * also consult the vmf_insert_mixed_prot() documentation when | |
921 | * @pgprot != @vmf->vma->vm_page_prot. | |
922 | * | |
923 | * Return: vm_fault_t value. | |
924 | */ | |
925 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
926 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 927 | { |
fce86ff5 DW |
928 | unsigned long addr = vmf->address & PUD_MASK; |
929 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 930 | |
a00cc7d9 MW |
931 | /* |
932 | * If we had pud_special, we could avoid all these restrictions, | |
933 | * but we need to be consistent with PTEs and architectures that | |
934 | * can't support a 'special' bit. | |
935 | */ | |
62ec0d8c DJ |
936 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
937 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
938 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
939 | (VM_PFNMAP|VM_MIXEDMAP)); | |
940 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
941 | |
942 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
943 | return VM_FAULT_SIGBUS; | |
944 | ||
945 | track_pfn_insert(vma, &pgprot, pfn); | |
946 | ||
fce86ff5 | 947 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
948 | return VM_FAULT_NOPAGE; |
949 | } | |
9a9731b1 | 950 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
951 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
952 | ||
3565fce3 | 953 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 954 | pmd_t *pmd, int flags) |
3565fce3 DW |
955 | { |
956 | pmd_t _pmd; | |
957 | ||
a8f97366 KS |
958 | _pmd = pmd_mkyoung(*pmd); |
959 | if (flags & FOLL_WRITE) | |
960 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 961 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 962 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
963 | update_mmu_cache_pmd(vma, addr, pmd); |
964 | } | |
965 | ||
966 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 967 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
968 | { |
969 | unsigned long pfn = pmd_pfn(*pmd); | |
970 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
971 | struct page *page; |
972 | ||
973 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
974 | ||
8310d48b KF |
975 | /* |
976 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
977 | * not be in this function with `flags & FOLL_COW` set. | |
978 | */ | |
979 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
980 | ||
3faa52c0 JH |
981 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
982 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
983 | (FOLL_PIN | FOLL_GET))) | |
984 | return NULL; | |
985 | ||
f6f37321 | 986 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
987 | return NULL; |
988 | ||
989 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
990 | /* pass */; | |
991 | else | |
992 | return NULL; | |
993 | ||
994 | if (flags & FOLL_TOUCH) | |
a8f97366 | 995 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
996 | |
997 | /* | |
998 | * device mapped pages can only be returned if the | |
999 | * caller will manage the page reference count. | |
1000 | */ | |
3faa52c0 | 1001 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1002 | return ERR_PTR(-EEXIST); |
1003 | ||
1004 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1005 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1006 | if (!*pgmap) | |
3565fce3 DW |
1007 | return ERR_PTR(-EFAULT); |
1008 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1009 | if (!try_grab_page(page, flags)) |
1010 | page = ERR_PTR(-ENOMEM); | |
3565fce3 DW |
1011 | |
1012 | return page; | |
1013 | } | |
1014 | ||
71e3aac0 AA |
1015 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1016 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
1017 | struct vm_area_struct *vma) | |
1018 | { | |
c4088ebd | 1019 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1020 | struct page *src_page; |
1021 | pmd_t pmd; | |
12c9d70b | 1022 | pgtable_t pgtable = NULL; |
628d47ce | 1023 | int ret = -ENOMEM; |
71e3aac0 | 1024 | |
628d47ce KS |
1025 | /* Skip if can be re-fill on fault */ |
1026 | if (!vma_is_anonymous(vma)) | |
1027 | return 0; | |
1028 | ||
4cf58924 | 1029 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1030 | if (unlikely(!pgtable)) |
1031 | goto out; | |
71e3aac0 | 1032 | |
c4088ebd KS |
1033 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1034 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1035 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1036 | |
1037 | ret = -EAGAIN; | |
1038 | pmd = *src_pmd; | |
84c3fc4e | 1039 | |
b569a176 PX |
1040 | /* |
1041 | * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA | |
1042 | * does not have the VM_UFFD_WP, which means that the uffd | |
1043 | * fork event is not enabled. | |
1044 | */ | |
1045 | if (!(vma->vm_flags & VM_UFFD_WP)) | |
1046 | pmd = pmd_clear_uffd_wp(pmd); | |
1047 | ||
84c3fc4e ZY |
1048 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1049 | if (unlikely(is_swap_pmd(pmd))) { | |
1050 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1051 | ||
1052 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
1053 | if (is_write_migration_entry(entry)) { | |
1054 | make_migration_entry_read(&entry); | |
1055 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1056 | if (pmd_swp_soft_dirty(*src_pmd)) |
1057 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
1058 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1059 | } | |
dd8a67f9 | 1060 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1061 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1062 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
1063 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1064 | ret = 0; | |
1065 | goto out_unlock; | |
1066 | } | |
1067 | #endif | |
1068 | ||
628d47ce | 1069 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1070 | pte_free(dst_mm, pgtable); |
1071 | goto out_unlock; | |
1072 | } | |
fc9fe822 | 1073 | /* |
c4088ebd | 1074 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1075 | * under splitting since we don't split the page itself, only pmd to |
1076 | * a page table. | |
1077 | */ | |
1078 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 1079 | struct page *zero_page; |
97ae1749 KS |
1080 | /* |
1081 | * get_huge_zero_page() will never allocate a new page here, | |
1082 | * since we already have a zero page to copy. It just takes a | |
1083 | * reference. | |
1084 | */ | |
6fcb52a5 | 1085 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 1086 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 1087 | zero_page); |
fc9fe822 KS |
1088 | ret = 0; |
1089 | goto out_unlock; | |
1090 | } | |
de466bd6 | 1091 | |
628d47ce KS |
1092 | src_page = pmd_page(pmd); |
1093 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e PX |
1094 | |
1095 | /* | |
1096 | * If this page is a potentially pinned page, split and retry the fault | |
1097 | * with smaller page size. Normally this should not happen because the | |
1098 | * userspace should use MADV_DONTFORK upon pinned regions. This is a | |
1099 | * best effort that the pinned pages won't be replaced by another | |
1100 | * random page during the coming copy-on-write. | |
1101 | */ | |
97a7e473 | 1102 | if (unlikely(page_needs_cow_for_dma(vma, src_page))) { |
d042035e PX |
1103 | pte_free(dst_mm, pgtable); |
1104 | spin_unlock(src_ptl); | |
1105 | spin_unlock(dst_ptl); | |
1106 | __split_huge_pmd(vma, src_pmd, addr, false, NULL); | |
1107 | return -EAGAIN; | |
1108 | } | |
1109 | ||
628d47ce KS |
1110 | get_page(src_page); |
1111 | page_dup_rmap(src_page, true); | |
1112 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 1113 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1114 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
1115 | |
1116 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
1117 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
1118 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1119 | |
1120 | ret = 0; | |
1121 | out_unlock: | |
c4088ebd KS |
1122 | spin_unlock(src_ptl); |
1123 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1124 | out: |
1125 | return ret; | |
1126 | } | |
1127 | ||
a00cc7d9 MW |
1128 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1129 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1130 | pud_t *pud, int flags) |
a00cc7d9 MW |
1131 | { |
1132 | pud_t _pud; | |
1133 | ||
a8f97366 KS |
1134 | _pud = pud_mkyoung(*pud); |
1135 | if (flags & FOLL_WRITE) | |
1136 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1137 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1138 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1139 | update_mmu_cache_pud(vma, addr, pud); |
1140 | } | |
1141 | ||
1142 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1143 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1144 | { |
1145 | unsigned long pfn = pud_pfn(*pud); | |
1146 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1147 | struct page *page; |
1148 | ||
1149 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1150 | ||
f6f37321 | 1151 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1152 | return NULL; |
1153 | ||
3faa52c0 JH |
1154 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1155 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1156 | (FOLL_PIN | FOLL_GET))) | |
1157 | return NULL; | |
1158 | ||
a00cc7d9 MW |
1159 | if (pud_present(*pud) && pud_devmap(*pud)) |
1160 | /* pass */; | |
1161 | else | |
1162 | return NULL; | |
1163 | ||
1164 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1165 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1166 | |
1167 | /* | |
1168 | * device mapped pages can only be returned if the | |
1169 | * caller will manage the page reference count. | |
3faa52c0 JH |
1170 | * |
1171 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1172 | */ |
3faa52c0 | 1173 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1174 | return ERR_PTR(-EEXIST); |
1175 | ||
1176 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1177 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1178 | if (!*pgmap) | |
a00cc7d9 MW |
1179 | return ERR_PTR(-EFAULT); |
1180 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1181 | if (!try_grab_page(page, flags)) |
1182 | page = ERR_PTR(-ENOMEM); | |
a00cc7d9 MW |
1183 | |
1184 | return page; | |
1185 | } | |
1186 | ||
1187 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1188 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1189 | struct vm_area_struct *vma) | |
1190 | { | |
1191 | spinlock_t *dst_ptl, *src_ptl; | |
1192 | pud_t pud; | |
1193 | int ret; | |
1194 | ||
1195 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1196 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1197 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1198 | ||
1199 | ret = -EAGAIN; | |
1200 | pud = *src_pud; | |
1201 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1202 | goto out_unlock; | |
1203 | ||
1204 | /* | |
1205 | * When page table lock is held, the huge zero pud should not be | |
1206 | * under splitting since we don't split the page itself, only pud to | |
1207 | * a page table. | |
1208 | */ | |
1209 | if (is_huge_zero_pud(pud)) { | |
1210 | /* No huge zero pud yet */ | |
1211 | } | |
1212 | ||
d042035e | 1213 | /* Please refer to comments in copy_huge_pmd() */ |
97a7e473 | 1214 | if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) { |
d042035e PX |
1215 | spin_unlock(src_ptl); |
1216 | spin_unlock(dst_ptl); | |
1217 | __split_huge_pud(vma, src_pud, addr); | |
1218 | return -EAGAIN; | |
1219 | } | |
1220 | ||
a00cc7d9 MW |
1221 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1222 | pud = pud_mkold(pud_wrprotect(pud)); | |
1223 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1224 | ||
1225 | ret = 0; | |
1226 | out_unlock: | |
1227 | spin_unlock(src_ptl); | |
1228 | spin_unlock(dst_ptl); | |
1229 | return ret; | |
1230 | } | |
1231 | ||
1232 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1233 | { | |
1234 | pud_t entry; | |
1235 | unsigned long haddr; | |
1236 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1237 | ||
1238 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1239 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1240 | goto unlock; | |
1241 | ||
1242 | entry = pud_mkyoung(orig_pud); | |
1243 | if (write) | |
1244 | entry = pud_mkdirty(entry); | |
1245 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1246 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1247 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1248 | ||
1249 | unlock: | |
1250 | spin_unlock(vmf->ptl); | |
1251 | } | |
1252 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1253 | ||
82b0f8c3 | 1254 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1255 | { |
1256 | pmd_t entry; | |
1257 | unsigned long haddr; | |
20f664aa | 1258 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1259 | |
82b0f8c3 JK |
1260 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1261 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1262 | goto unlock; |
1263 | ||
1264 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1265 | if (write) |
1266 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1267 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1268 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1269 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1270 | |
1271 | unlock: | |
82b0f8c3 | 1272 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1273 | } |
1274 | ||
2b740303 | 1275 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1276 | { |
82b0f8c3 | 1277 | struct vm_area_struct *vma = vmf->vma; |
3917c802 | 1278 | struct page *page; |
82b0f8c3 | 1279 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 1280 | |
82b0f8c3 | 1281 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1282 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1283 | |
93b4796d | 1284 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1285 | goto fallback; |
1286 | ||
82b0f8c3 | 1287 | spin_lock(vmf->ptl); |
3917c802 KS |
1288 | |
1289 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1290 | spin_unlock(vmf->ptl); | |
1291 | return 0; | |
1292 | } | |
71e3aac0 AA |
1293 | |
1294 | page = pmd_page(orig_pmd); | |
f6004e73 | 1295 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 KS |
1296 | |
1297 | /* Lock page for reuse_swap_page() */ | |
ba3c4ce6 HY |
1298 | if (!trylock_page(page)) { |
1299 | get_page(page); | |
1300 | spin_unlock(vmf->ptl); | |
1301 | lock_page(page); | |
1302 | spin_lock(vmf->ptl); | |
1303 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1304 | spin_unlock(vmf->ptl); |
ba3c4ce6 HY |
1305 | unlock_page(page); |
1306 | put_page(page); | |
3917c802 | 1307 | return 0; |
ba3c4ce6 HY |
1308 | } |
1309 | put_page(page); | |
1310 | } | |
3917c802 KS |
1311 | |
1312 | /* | |
1313 | * We can only reuse the page if nobody else maps the huge page or it's | |
1314 | * part. | |
1315 | */ | |
ba3c4ce6 | 1316 | if (reuse_swap_page(page, NULL)) { |
71e3aac0 AA |
1317 | pmd_t entry; |
1318 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1319 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1320 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1321 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
ba3c4ce6 | 1322 | unlock_page(page); |
82b0f8c3 | 1323 | spin_unlock(vmf->ptl); |
3917c802 | 1324 | return VM_FAULT_WRITE; |
71e3aac0 | 1325 | } |
3917c802 KS |
1326 | |
1327 | unlock_page(page); | |
82b0f8c3 | 1328 | spin_unlock(vmf->ptl); |
3917c802 KS |
1329 | fallback: |
1330 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1331 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1332 | } |
1333 | ||
8310d48b | 1334 | /* |
a308c71b PX |
1335 | * FOLL_FORCE can write to even unwritable pmd's, but only |
1336 | * after we've gone through a COW cycle and they are dirty. | |
8310d48b KF |
1337 | */ |
1338 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1339 | { | |
a308c71b PX |
1340 | return pmd_write(pmd) || |
1341 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
8310d48b KF |
1342 | } |
1343 | ||
b676b293 | 1344 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1345 | unsigned long addr, |
1346 | pmd_t *pmd, | |
1347 | unsigned int flags) | |
1348 | { | |
b676b293 | 1349 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1350 | struct page *page = NULL; |
1351 | ||
c4088ebd | 1352 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1353 | |
8310d48b | 1354 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1355 | goto out; |
1356 | ||
85facf25 KS |
1357 | /* Avoid dumping huge zero page */ |
1358 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1359 | return ERR_PTR(-EFAULT); | |
1360 | ||
2b4847e7 | 1361 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1362 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1363 | goto out; |
1364 | ||
71e3aac0 | 1365 | page = pmd_page(*pmd); |
ca120cf6 | 1366 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3faa52c0 JH |
1367 | |
1368 | if (!try_grab_page(page, flags)) | |
1369 | return ERR_PTR(-ENOMEM); | |
1370 | ||
3565fce3 | 1371 | if (flags & FOLL_TOUCH) |
a8f97366 | 1372 | touch_pmd(vma, addr, pmd, flags); |
3faa52c0 | 1373 | |
de60f5f1 | 1374 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1375 | /* |
1376 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1377 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1378 | * | |
9a73f61b KS |
1379 | * For anon THP: |
1380 | * | |
e90309c9 KS |
1381 | * In most cases the pmd is the only mapping of the page as we |
1382 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1383 | * writable private mappings in populate_vma_page_range(). | |
1384 | * | |
1385 | * The only scenario when we have the page shared here is if we | |
1386 | * mlocking read-only mapping shared over fork(). We skip | |
1387 | * mlocking such pages. | |
9a73f61b KS |
1388 | * |
1389 | * For file THP: | |
1390 | * | |
1391 | * We can expect PageDoubleMap() to be stable under page lock: | |
1392 | * for file pages we set it in page_add_file_rmap(), which | |
1393 | * requires page to be locked. | |
e90309c9 | 1394 | */ |
9a73f61b KS |
1395 | |
1396 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1397 | goto skip_mlock; | |
1398 | if (PageDoubleMap(page) || !page->mapping) | |
1399 | goto skip_mlock; | |
1400 | if (!trylock_page(page)) | |
1401 | goto skip_mlock; | |
9a73f61b KS |
1402 | if (page->mapping && !PageDoubleMap(page)) |
1403 | mlock_vma_page(page); | |
1404 | unlock_page(page); | |
b676b293 | 1405 | } |
9a73f61b | 1406 | skip_mlock: |
71e3aac0 | 1407 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1408 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 AA |
1409 | |
1410 | out: | |
1411 | return page; | |
1412 | } | |
1413 | ||
d10e63f2 | 1414 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1415 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1416 | { |
82b0f8c3 | 1417 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1418 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1419 | struct page *page; |
82b0f8c3 | 1420 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1421 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1422 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1423 | bool page_locked; |
1424 | bool migrated = false; | |
b191f9b1 | 1425 | bool was_writable; |
6688cc05 | 1426 | int flags = 0; |
d10e63f2 | 1427 | |
82b0f8c3 JK |
1428 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1429 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1430 | goto out_unlock; |
1431 | ||
de466bd6 MG |
1432 | /* |
1433 | * If there are potential migrations, wait for completion and retry | |
1434 | * without disrupting NUMA hinting information. Do not relock and | |
1435 | * check_same as the page may no longer be mapped. | |
1436 | */ | |
82b0f8c3 JK |
1437 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1438 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1439 | if (!get_page_unless_zero(page)) |
1440 | goto out_unlock; | |
82b0f8c3 | 1441 | spin_unlock(vmf->ptl); |
48054625 | 1442 | put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE); |
de466bd6 MG |
1443 | goto out; |
1444 | } | |
1445 | ||
d10e63f2 | 1446 | page = pmd_page(pmd); |
a1a46184 | 1447 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1448 | page_nid = page_to_nid(page); |
90572890 | 1449 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1450 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1451 | if (page_nid == this_nid) { |
03c5a6e1 | 1452 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1453 | flags |= TNF_FAULT_LOCAL; |
1454 | } | |
4daae3b4 | 1455 | |
bea66fbd | 1456 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1457 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1458 | flags |= TNF_NO_GROUP; |
1459 | ||
ff9042b1 MG |
1460 | /* |
1461 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1462 | * page_table_lock if at all possible | |
1463 | */ | |
b8916634 MG |
1464 | page_locked = trylock_page(page); |
1465 | target_nid = mpol_misplaced(page, vma, haddr); | |
de466bd6 | 1466 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1467 | if (!page_locked) { |
98fa15f3 | 1468 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1469 | if (!get_page_unless_zero(page)) |
1470 | goto out_unlock; | |
82b0f8c3 | 1471 | spin_unlock(vmf->ptl); |
48054625 | 1472 | put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE); |
b8916634 | 1473 | goto out; |
6beb5e8b ML |
1474 | } else if (target_nid == NUMA_NO_NODE) { |
1475 | /* There are no parallel migrations and page is in the right | |
1476 | * node. Clear the numa hinting info in this pmd. | |
1477 | */ | |
1478 | goto clear_pmdnuma; | |
b8916634 MG |
1479 | } |
1480 | ||
2b4847e7 MG |
1481 | /* |
1482 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1483 | * to serialises splits | |
1484 | */ | |
b8916634 | 1485 | get_page(page); |
82b0f8c3 | 1486 | spin_unlock(vmf->ptl); |
b8916634 | 1487 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1488 | |
c69307d5 | 1489 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1490 | spin_lock(vmf->ptl); |
1491 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1492 | unlock_page(page); |
1493 | put_page(page); | |
98fa15f3 | 1494 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1495 | goto out_unlock; |
b32967ff | 1496 | } |
ff9042b1 | 1497 | |
c3a489ca MG |
1498 | /* Bail if we fail to protect against THP splits for any reason */ |
1499 | if (unlikely(!anon_vma)) { | |
1500 | put_page(page); | |
98fa15f3 | 1501 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1502 | goto clear_pmdnuma; |
1503 | } | |
1504 | ||
8b1b436d PZ |
1505 | /* |
1506 | * Since we took the NUMA fault, we must have observed the !accessible | |
1507 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1508 | * modifying the page we're about to migrate. | |
1509 | * | |
1510 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1511 | * inc_tlb_flush_pending(). |
1512 | * | |
1513 | * We are not sure a pending tlb flush here is for a huge page | |
1514 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1515 | */ |
7066f0f9 | 1516 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1517 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1518 | /* |
1519 | * change_huge_pmd() released the pmd lock before | |
1520 | * invalidating the secondary MMUs sharing the primary | |
1521 | * MMU pagetables (with ->invalidate_range()). The | |
1522 | * mmu_notifier_invalidate_range_end() (which | |
1523 | * internally calls ->invalidate_range()) in | |
1524 | * change_pmd_range() will run after us, so we can't | |
1525 | * rely on it here and we need an explicit invalidate. | |
1526 | */ | |
1527 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1528 | haddr + HPAGE_PMD_SIZE); | |
1529 | } | |
8b1b436d | 1530 | |
a54a407f MG |
1531 | /* |
1532 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1533 | * and access rights restored. |
a54a407f | 1534 | */ |
82b0f8c3 | 1535 | spin_unlock(vmf->ptl); |
8b1b436d | 1536 | |
bae473a4 | 1537 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1538 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1539 | if (migrated) { |
1540 | flags |= TNF_MIGRATED; | |
8191acbd | 1541 | page_nid = target_nid; |
074c2381 MG |
1542 | } else |
1543 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1544 | |
8191acbd | 1545 | goto out; |
b32967ff | 1546 | clear_pmdnuma: |
a54a407f | 1547 | BUG_ON(!PageLocked(page)); |
288bc549 | 1548 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1549 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1550 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1551 | if (was_writable) |
1552 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1553 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1554 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1555 | unlock_page(page); |
d10e63f2 | 1556 | out_unlock: |
82b0f8c3 | 1557 | spin_unlock(vmf->ptl); |
b8916634 MG |
1558 | |
1559 | out: | |
1560 | if (anon_vma) | |
1561 | page_unlock_anon_vma_read(anon_vma); | |
1562 | ||
98fa15f3 | 1563 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1564 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1565 | flags); |
8191acbd | 1566 | |
d10e63f2 MG |
1567 | return 0; |
1568 | } | |
1569 | ||
319904ad HY |
1570 | /* |
1571 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1572 | * Otherwise, return false. | |
1573 | */ | |
1574 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1575 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1576 | { |
1577 | spinlock_t *ptl; | |
1578 | pmd_t orig_pmd; | |
1579 | struct page *page; | |
1580 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1581 | bool ret = false; |
b8d3c4c3 | 1582 | |
ed6a7935 | 1583 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1584 | |
b6ec57f4 KS |
1585 | ptl = pmd_trans_huge_lock(pmd, vma); |
1586 | if (!ptl) | |
25eedabe | 1587 | goto out_unlocked; |
b8d3c4c3 MK |
1588 | |
1589 | orig_pmd = *pmd; | |
319904ad | 1590 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1591 | goto out; |
b8d3c4c3 | 1592 | |
84c3fc4e ZY |
1593 | if (unlikely(!pmd_present(orig_pmd))) { |
1594 | VM_BUG_ON(thp_migration_supported() && | |
1595 | !is_pmd_migration_entry(orig_pmd)); | |
1596 | goto out; | |
1597 | } | |
1598 | ||
b8d3c4c3 MK |
1599 | page = pmd_page(orig_pmd); |
1600 | /* | |
1601 | * If other processes are mapping this page, we couldn't discard | |
1602 | * the page unless they all do MADV_FREE so let's skip the page. | |
1603 | */ | |
1604 | if (page_mapcount(page) != 1) | |
1605 | goto out; | |
1606 | ||
1607 | if (!trylock_page(page)) | |
1608 | goto out; | |
1609 | ||
1610 | /* | |
1611 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1612 | * will deactivate only them. | |
1613 | */ | |
1614 | if (next - addr != HPAGE_PMD_SIZE) { | |
1615 | get_page(page); | |
1616 | spin_unlock(ptl); | |
9818b8cd | 1617 | split_huge_page(page); |
b8d3c4c3 | 1618 | unlock_page(page); |
bbf29ffc | 1619 | put_page(page); |
b8d3c4c3 MK |
1620 | goto out_unlocked; |
1621 | } | |
1622 | ||
1623 | if (PageDirty(page)) | |
1624 | ClearPageDirty(page); | |
1625 | unlock_page(page); | |
1626 | ||
b8d3c4c3 | 1627 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1628 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1629 | orig_pmd = pmd_mkold(orig_pmd); |
1630 | orig_pmd = pmd_mkclean(orig_pmd); | |
1631 | ||
1632 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1633 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1634 | } | |
802a3a92 SL |
1635 | |
1636 | mark_page_lazyfree(page); | |
319904ad | 1637 | ret = true; |
b8d3c4c3 MK |
1638 | out: |
1639 | spin_unlock(ptl); | |
1640 | out_unlocked: | |
1641 | return ret; | |
1642 | } | |
1643 | ||
953c66c2 AK |
1644 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1645 | { | |
1646 | pgtable_t pgtable; | |
1647 | ||
1648 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1649 | pte_free(mm, pgtable); | |
c4812909 | 1650 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1651 | } |
1652 | ||
71e3aac0 | 1653 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1654 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1655 | { |
da146769 | 1656 | pmd_t orig_pmd; |
bf929152 | 1657 | spinlock_t *ptl; |
71e3aac0 | 1658 | |
ed6a7935 | 1659 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1660 | |
b6ec57f4 KS |
1661 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1662 | if (!ptl) | |
da146769 KS |
1663 | return 0; |
1664 | /* | |
1665 | * For architectures like ppc64 we look at deposited pgtable | |
1666 | * when calling pmdp_huge_get_and_clear. So do the | |
1667 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1668 | * operations. | |
1669 | */ | |
93a98695 AK |
1670 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1671 | tlb->fullmm); | |
da146769 | 1672 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1673 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1674 | if (arch_needs_pgtable_deposit()) |
1675 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1676 | spin_unlock(ptl); |
1677 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1678 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1679 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1680 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1681 | spin_unlock(ptl); |
c0f2e176 | 1682 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1683 | } else { |
616b8371 ZY |
1684 | struct page *page = NULL; |
1685 | int flush_needed = 1; | |
1686 | ||
1687 | if (pmd_present(orig_pmd)) { | |
1688 | page = pmd_page(orig_pmd); | |
1689 | page_remove_rmap(page, true); | |
1690 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1691 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1692 | } else if (thp_migration_supported()) { | |
1693 | swp_entry_t entry; | |
1694 | ||
1695 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1696 | entry = pmd_to_swp_entry(orig_pmd); | |
a44f89dc | 1697 | page = migration_entry_to_page(entry); |
616b8371 ZY |
1698 | flush_needed = 0; |
1699 | } else | |
1700 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1701 | ||
b5072380 | 1702 | if (PageAnon(page)) { |
c14a6eb4 | 1703 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1704 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1705 | } else { | |
953c66c2 AK |
1706 | if (arch_needs_pgtable_deposit()) |
1707 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1708 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1709 | } |
616b8371 | 1710 | |
da146769 | 1711 | spin_unlock(ptl); |
616b8371 ZY |
1712 | if (flush_needed) |
1713 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1714 | } |
da146769 | 1715 | return 1; |
71e3aac0 AA |
1716 | } |
1717 | ||
1dd38b6c AK |
1718 | #ifndef pmd_move_must_withdraw |
1719 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1720 | spinlock_t *old_pmd_ptl, | |
1721 | struct vm_area_struct *vma) | |
1722 | { | |
1723 | /* | |
1724 | * With split pmd lock we also need to move preallocated | |
1725 | * PTE page table if new_pmd is on different PMD page table. | |
1726 | * | |
1727 | * We also don't deposit and withdraw tables for file pages. | |
1728 | */ | |
1729 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1730 | } | |
1731 | #endif | |
1732 | ||
ab6e3d09 NH |
1733 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1734 | { | |
1735 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1736 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1737 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1738 | else if (pmd_present(pmd)) | |
1739 | pmd = pmd_mksoft_dirty(pmd); | |
1740 | #endif | |
1741 | return pmd; | |
1742 | } | |
1743 | ||
bf8616d5 | 1744 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1745 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1746 | { |
bf929152 | 1747 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1748 | pmd_t pmd; |
37a1c49a | 1749 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1750 | bool force_flush = false; |
37a1c49a | 1751 | |
37a1c49a AA |
1752 | /* |
1753 | * The destination pmd shouldn't be established, free_pgtables() | |
1754 | * should have release it. | |
1755 | */ | |
1756 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1757 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1758 | return false; |
37a1c49a AA |
1759 | } |
1760 | ||
bf929152 KS |
1761 | /* |
1762 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1763 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1764 | */ |
b6ec57f4 KS |
1765 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1766 | if (old_ptl) { | |
bf929152 KS |
1767 | new_ptl = pmd_lockptr(mm, new_pmd); |
1768 | if (new_ptl != old_ptl) | |
1769 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1770 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1771 | if (pmd_present(pmd)) |
a2ce2666 | 1772 | force_flush = true; |
025c5b24 | 1773 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1774 | |
1dd38b6c | 1775 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1776 | pgtable_t pgtable; |
3592806c KS |
1777 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1778 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1779 | } |
ab6e3d09 NH |
1780 | pmd = move_soft_dirty_pmd(pmd); |
1781 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1782 | if (force_flush) |
1783 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1784 | if (new_ptl != old_ptl) |
1785 | spin_unlock(new_ptl); | |
bf929152 | 1786 | spin_unlock(old_ptl); |
4b471e88 | 1787 | return true; |
37a1c49a | 1788 | } |
4b471e88 | 1789 | return false; |
37a1c49a AA |
1790 | } |
1791 | ||
f123d74a MG |
1792 | /* |
1793 | * Returns | |
1794 | * - 0 if PMD could not be locked | |
f0953a1b IM |
1795 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
1796 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary | |
f123d74a | 1797 | */ |
cd7548ab | 1798 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
58705444 | 1799 | unsigned long addr, pgprot_t newprot, unsigned long cp_flags) |
cd7548ab JW |
1800 | { |
1801 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1802 | spinlock_t *ptl; |
0a85e51d KS |
1803 | pmd_t entry; |
1804 | bool preserve_write; | |
1805 | int ret; | |
58705444 | 1806 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1807 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1808 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
cd7548ab | 1809 | |
b6ec57f4 | 1810 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1811 | if (!ptl) |
1812 | return 0; | |
e944fd67 | 1813 | |
0a85e51d KS |
1814 | preserve_write = prot_numa && pmd_write(*pmd); |
1815 | ret = 1; | |
e944fd67 | 1816 | |
84c3fc4e ZY |
1817 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1818 | if (is_swap_pmd(*pmd)) { | |
1819 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1820 | ||
1821 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1822 | if (is_write_migration_entry(entry)) { | |
1823 | pmd_t newpmd; | |
1824 | /* | |
1825 | * A protection check is difficult so | |
1826 | * just be safe and disable write | |
1827 | */ | |
1828 | make_migration_entry_read(&entry); | |
1829 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1830 | if (pmd_swp_soft_dirty(*pmd)) |
1831 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1832 | set_pmd_at(mm, addr, pmd, newpmd); |
1833 | } | |
1834 | goto unlock; | |
1835 | } | |
1836 | #endif | |
1837 | ||
0a85e51d KS |
1838 | /* |
1839 | * Avoid trapping faults against the zero page. The read-only | |
1840 | * data is likely to be read-cached on the local CPU and | |
1841 | * local/remote hits to the zero page are not interesting. | |
1842 | */ | |
1843 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1844 | goto unlock; | |
025c5b24 | 1845 | |
0a85e51d KS |
1846 | if (prot_numa && pmd_protnone(*pmd)) |
1847 | goto unlock; | |
1848 | ||
ced10803 | 1849 | /* |
3e4e28c5 | 1850 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1851 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1852 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1853 | * |
1854 | * CPU0: CPU1: | |
1855 | * change_huge_pmd(prot_numa=1) | |
1856 | * pmdp_huge_get_and_clear_notify() | |
1857 | * madvise_dontneed() | |
1858 | * zap_pmd_range() | |
1859 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1860 | * // skip the pmd | |
1861 | * set_pmd_at(); | |
1862 | * // pmd is re-established | |
1863 | * | |
1864 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1865 | * which may break userspace. | |
1866 | * | |
1867 | * pmdp_invalidate() is required to make sure we don't miss | |
1868 | * dirty/young flags set by hardware. | |
1869 | */ | |
a3cf988f | 1870 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1871 | |
0a85e51d KS |
1872 | entry = pmd_modify(entry, newprot); |
1873 | if (preserve_write) | |
1874 | entry = pmd_mk_savedwrite(entry); | |
292924b2 PX |
1875 | if (uffd_wp) { |
1876 | entry = pmd_wrprotect(entry); | |
1877 | entry = pmd_mkuffd_wp(entry); | |
1878 | } else if (uffd_wp_resolve) { | |
1879 | /* | |
1880 | * Leave the write bit to be handled by PF interrupt | |
1881 | * handler, then things like COW could be properly | |
1882 | * handled. | |
1883 | */ | |
1884 | entry = pmd_clear_uffd_wp(entry); | |
1885 | } | |
0a85e51d KS |
1886 | ret = HPAGE_PMD_NR; |
1887 | set_pmd_at(mm, addr, pmd, entry); | |
1888 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1889 | unlock: | |
1890 | spin_unlock(ptl); | |
025c5b24 NH |
1891 | return ret; |
1892 | } | |
1893 | ||
1894 | /* | |
8f19b0c0 | 1895 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1896 | * |
8f19b0c0 HY |
1897 | * Note that if it returns page table lock pointer, this routine returns without |
1898 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1899 | */ |
b6ec57f4 | 1900 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1901 | { |
b6ec57f4 KS |
1902 | spinlock_t *ptl; |
1903 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1904 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1905 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1906 | return ptl; |
1907 | spin_unlock(ptl); | |
1908 | return NULL; | |
cd7548ab JW |
1909 | } |
1910 | ||
a00cc7d9 MW |
1911 | /* |
1912 | * Returns true if a given pud maps a thp, false otherwise. | |
1913 | * | |
1914 | * Note that if it returns true, this routine returns without unlocking page | |
1915 | * table lock. So callers must unlock it. | |
1916 | */ | |
1917 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1918 | { | |
1919 | spinlock_t *ptl; | |
1920 | ||
1921 | ptl = pud_lock(vma->vm_mm, pud); | |
1922 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1923 | return ptl; | |
1924 | spin_unlock(ptl); | |
1925 | return NULL; | |
1926 | } | |
1927 | ||
1928 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1929 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1930 | pud_t *pud, unsigned long addr) | |
1931 | { | |
a00cc7d9 MW |
1932 | spinlock_t *ptl; |
1933 | ||
1934 | ptl = __pud_trans_huge_lock(pud, vma); | |
1935 | if (!ptl) | |
1936 | return 0; | |
1937 | /* | |
1938 | * For architectures like ppc64 we look at deposited pgtable | |
1939 | * when calling pudp_huge_get_and_clear. So do the | |
1940 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1941 | * operations. | |
1942 | */ | |
70516b93 | 1943 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1944 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1945 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1946 | spin_unlock(ptl); |
1947 | /* No zero page support yet */ | |
1948 | } else { | |
1949 | /* No support for anonymous PUD pages yet */ | |
1950 | BUG(); | |
1951 | } | |
1952 | return 1; | |
1953 | } | |
1954 | ||
1955 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1956 | unsigned long haddr) | |
1957 | { | |
1958 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1959 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1960 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1961 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1962 | ||
ce9311cf | 1963 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1964 | |
1965 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1966 | } | |
1967 | ||
1968 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1969 | unsigned long address) | |
1970 | { | |
1971 | spinlock_t *ptl; | |
ac46d4f3 | 1972 | struct mmu_notifier_range range; |
a00cc7d9 | 1973 | |
7269f999 | 1974 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 1975 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
1976 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
1977 | mmu_notifier_invalidate_range_start(&range); | |
1978 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
1979 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
1980 | goto out; | |
ac46d4f3 | 1981 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
1982 | |
1983 | out: | |
1984 | spin_unlock(ptl); | |
4645b9fe JG |
1985 | /* |
1986 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1987 | * the above pudp_huge_clear_flush_notify() did already call it. | |
1988 | */ | |
ac46d4f3 | 1989 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
1990 | } |
1991 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1992 | ||
eef1b3ba KS |
1993 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1994 | unsigned long haddr, pmd_t *pmd) | |
1995 | { | |
1996 | struct mm_struct *mm = vma->vm_mm; | |
1997 | pgtable_t pgtable; | |
1998 | pmd_t _pmd; | |
1999 | int i; | |
2000 | ||
0f10851e JG |
2001 | /* |
2002 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2003 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2004 | * replacing a zero pmd write protected page with a zero pte write | |
2005 | * protected page. | |
2006 | * | |
ad56b738 | 2007 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2008 | */ |
2009 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2010 | |
2011 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2012 | pmd_populate(mm, &_pmd, pgtable); | |
2013 | ||
2014 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2015 | pte_t *pte, entry; | |
2016 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2017 | entry = pte_mkspecial(entry); | |
2018 | pte = pte_offset_map(&_pmd, haddr); | |
2019 | VM_BUG_ON(!pte_none(*pte)); | |
2020 | set_pte_at(mm, haddr, pte, entry); | |
2021 | pte_unmap(pte); | |
2022 | } | |
2023 | smp_wmb(); /* make pte visible before pmd */ | |
2024 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2025 | } |
2026 | ||
2027 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2028 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2029 | { |
2030 | struct mm_struct *mm = vma->vm_mm; | |
2031 | struct page *page; | |
2032 | pgtable_t pgtable; | |
423ac9af | 2033 | pmd_t old_pmd, _pmd; |
292924b2 | 2034 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
2ac015e2 | 2035 | unsigned long addr; |
eef1b3ba KS |
2036 | int i; |
2037 | ||
2038 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2039 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2040 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2041 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2042 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2043 | |
2044 | count_vm_event(THP_SPLIT_PMD); | |
2045 | ||
d21b9e57 KS |
2046 | if (!vma_is_anonymous(vma)) { |
2047 | _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); | |
953c66c2 AK |
2048 | /* |
2049 | * We are going to unmap this huge page. So | |
2050 | * just go ahead and zap it | |
2051 | */ | |
2052 | if (arch_needs_pgtable_deposit()) | |
2053 | zap_deposited_table(mm, pmd); | |
2484ca9b | 2054 | if (vma_is_special_huge(vma)) |
d21b9e57 KS |
2055 | return; |
2056 | page = pmd_page(_pmd); | |
e1f1b157 HD |
2057 | if (!PageDirty(page) && pmd_dirty(_pmd)) |
2058 | set_page_dirty(page); | |
d21b9e57 KS |
2059 | if (!PageReferenced(page) && pmd_young(_pmd)) |
2060 | SetPageReferenced(page); | |
2061 | page_remove_rmap(page, true); | |
2062 | put_page(page); | |
fadae295 | 2063 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2064 | return; |
ec0abae6 | 2065 | } else if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2066 | /* |
2067 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2068 | * mmu_notifier_invalidate_range() see comments below inside | |
2069 | * __split_huge_pmd() ? | |
2070 | * | |
2071 | * We are going from a zero huge page write protected to zero | |
2072 | * small page also write protected so it does not seems useful | |
2073 | * to invalidate secondary mmu at this time. | |
2074 | */ | |
eef1b3ba KS |
2075 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2076 | } | |
2077 | ||
423ac9af AK |
2078 | /* |
2079 | * Up to this point the pmd is present and huge and userland has the | |
2080 | * whole access to the hugepage during the split (which happens in | |
2081 | * place). If we overwrite the pmd with the not-huge version pointing | |
2082 | * to the pte here (which of course we could if all CPUs were bug | |
2083 | * free), userland could trigger a small page size TLB miss on the | |
2084 | * small sized TLB while the hugepage TLB entry is still established in | |
2085 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2086 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2087 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2088 | * only safe if the permission and cache attributes of the two entries |
2089 | * loaded in the two TLB is identical (which should be the case here). | |
2090 | * But it is generally safer to never allow small and huge TLB entries | |
2091 | * for the same virtual address to be loaded simultaneously. So instead | |
2092 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2093 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2094 | * must remain set at all times on the pmd until the split is complete | |
2095 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2096 | * non-huge version of the pmd entry with pmd_populate. | |
2097 | */ | |
2098 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2099 | ||
423ac9af | 2100 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2101 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2102 | swp_entry_t entry; |
2103 | ||
423ac9af | 2104 | entry = pmd_to_swp_entry(old_pmd); |
a44f89dc | 2105 | page = migration_entry_to_page(entry); |
2e83ee1d PX |
2106 | write = is_write_migration_entry(entry); |
2107 | young = false; | |
2108 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
f45ec5ff | 2109 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2110 | } else { |
423ac9af | 2111 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2112 | if (pmd_dirty(old_pmd)) |
2113 | SetPageDirty(page); | |
2114 | write = pmd_write(old_pmd); | |
2115 | young = pmd_young(old_pmd); | |
2116 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2117 | uffd_wp = pmd_uffd_wp(old_pmd); |
2e83ee1d | 2118 | } |
eef1b3ba | 2119 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2120 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2121 | |
423ac9af AK |
2122 | /* |
2123 | * Withdraw the table only after we mark the pmd entry invalid. | |
2124 | * This's critical for some architectures (Power). | |
2125 | */ | |
eef1b3ba KS |
2126 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2127 | pmd_populate(mm, &_pmd, pgtable); | |
2128 | ||
2ac015e2 | 2129 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2130 | pte_t entry, *pte; |
2131 | /* | |
2132 | * Note that NUMA hinting access restrictions are not | |
2133 | * transferred to avoid any possibility of altering | |
2134 | * permissions across VMAs. | |
2135 | */ | |
84c3fc4e | 2136 | if (freeze || pmd_migration) { |
ba988280 KS |
2137 | swp_entry_t swp_entry; |
2138 | swp_entry = make_migration_entry(page + i, write); | |
2139 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2140 | if (soft_dirty) |
2141 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2142 | if (uffd_wp) |
2143 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2144 | } else { |
6d2329f8 | 2145 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2146 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2147 | if (!write) |
2148 | entry = pte_wrprotect(entry); | |
2149 | if (!young) | |
2150 | entry = pte_mkold(entry); | |
804dd150 AA |
2151 | if (soft_dirty) |
2152 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2153 | if (uffd_wp) |
2154 | entry = pte_mkuffd_wp(entry); | |
ba988280 | 2155 | } |
2ac015e2 | 2156 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2157 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2158 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2159 | if (!pmd_migration) |
eef1b3ba | 2160 | atomic_inc(&page[i]._mapcount); |
ec0abae6 | 2161 | pte_unmap(pte); |
eef1b3ba KS |
2162 | } |
2163 | ||
ec0abae6 RC |
2164 | if (!pmd_migration) { |
2165 | /* | |
2166 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2167 | * false-negative page_mapped(). | |
2168 | */ | |
2169 | if (compound_mapcount(page) > 1 && | |
2170 | !TestSetPageDoubleMap(page)) { | |
eef1b3ba | 2171 | for (i = 0; i < HPAGE_PMD_NR; i++) |
ec0abae6 RC |
2172 | atomic_inc(&page[i]._mapcount); |
2173 | } | |
2174 | ||
2175 | lock_page_memcg(page); | |
2176 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2177 | /* Last compound_mapcount is gone. */ | |
69473e5d MS |
2178 | __mod_lruvec_page_state(page, NR_ANON_THPS, |
2179 | -HPAGE_PMD_NR); | |
ec0abae6 RC |
2180 | if (TestClearPageDoubleMap(page)) { |
2181 | /* No need in mapcount reference anymore */ | |
2182 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2183 | atomic_dec(&page[i]._mapcount); | |
2184 | } | |
eef1b3ba | 2185 | } |
ec0abae6 | 2186 | unlock_page_memcg(page); |
eef1b3ba KS |
2187 | } |
2188 | ||
2189 | smp_wmb(); /* make pte visible before pmd */ | |
2190 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2191 | |
2192 | if (freeze) { | |
2ac015e2 | 2193 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2194 | page_remove_rmap(page + i, false); |
2195 | put_page(page + i); | |
2196 | } | |
2197 | } | |
eef1b3ba KS |
2198 | } |
2199 | ||
2200 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2201 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2202 | { |
2203 | spinlock_t *ptl; | |
ac46d4f3 | 2204 | struct mmu_notifier_range range; |
1c2f6730 | 2205 | bool do_unlock_page = false; |
c444eb56 | 2206 | pmd_t _pmd; |
eef1b3ba | 2207 | |
7269f999 | 2208 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2209 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2210 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2211 | mmu_notifier_invalidate_range_start(&range); | |
2212 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2213 | |
2214 | /* | |
2215 | * If caller asks to setup a migration entries, we need a page to check | |
2216 | * pmd against. Otherwise we can end up replacing wrong page. | |
2217 | */ | |
2218 | VM_BUG_ON(freeze && !page); | |
c444eb56 AA |
2219 | if (page) { |
2220 | VM_WARN_ON_ONCE(!PageLocked(page)); | |
c444eb56 AA |
2221 | if (page != pmd_page(*pmd)) |
2222 | goto out; | |
2223 | } | |
33f4751e | 2224 | |
c444eb56 | 2225 | repeat: |
5c7fb56e | 2226 | if (pmd_trans_huge(*pmd)) { |
c444eb56 AA |
2227 | if (!page) { |
2228 | page = pmd_page(*pmd); | |
1c2f6730 HD |
2229 | /* |
2230 | * An anonymous page must be locked, to ensure that a | |
2231 | * concurrent reuse_swap_page() sees stable mapcount; | |
2232 | * but reuse_swap_page() is not used on shmem or file, | |
2233 | * and page lock must not be taken when zap_pmd_range() | |
2234 | * calls __split_huge_pmd() while i_mmap_lock is held. | |
2235 | */ | |
2236 | if (PageAnon(page)) { | |
2237 | if (unlikely(!trylock_page(page))) { | |
2238 | get_page(page); | |
2239 | _pmd = *pmd; | |
2240 | spin_unlock(ptl); | |
2241 | lock_page(page); | |
2242 | spin_lock(ptl); | |
2243 | if (unlikely(!pmd_same(*pmd, _pmd))) { | |
2244 | unlock_page(page); | |
2245 | put_page(page); | |
2246 | page = NULL; | |
2247 | goto repeat; | |
2248 | } | |
c444eb56 | 2249 | put_page(page); |
c444eb56 | 2250 | } |
1c2f6730 | 2251 | do_unlock_page = true; |
c444eb56 AA |
2252 | } |
2253 | } | |
5c7fb56e | 2254 | if (PageMlocked(page)) |
5f737714 | 2255 | clear_page_mlock(page); |
84c3fc4e | 2256 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2257 | goto out; |
ac46d4f3 | 2258 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2259 | out: |
eef1b3ba | 2260 | spin_unlock(ptl); |
1c2f6730 | 2261 | if (do_unlock_page) |
c444eb56 | 2262 | unlock_page(page); |
4645b9fe JG |
2263 | /* |
2264 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2265 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2266 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2267 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2268 | * fault will trigger a flush_notify before pointing to a new page | |
2269 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2270 | * page in the meantime) | |
2271 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2272 | * to invalidate secondary tlb entry they are all still valid. | |
2273 | * any further changes to individual pte will notify. So no need | |
2274 | * to call mmu_notifier->invalidate_range() | |
2275 | */ | |
ac46d4f3 | 2276 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2277 | } |
2278 | ||
fec89c10 KS |
2279 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2280 | bool freeze, struct page *page) | |
94fcc585 | 2281 | { |
f72e7dcd | 2282 | pgd_t *pgd; |
c2febafc | 2283 | p4d_t *p4d; |
f72e7dcd | 2284 | pud_t *pud; |
94fcc585 AA |
2285 | pmd_t *pmd; |
2286 | ||
78ddc534 | 2287 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2288 | if (!pgd_present(*pgd)) |
2289 | return; | |
2290 | ||
c2febafc KS |
2291 | p4d = p4d_offset(pgd, address); |
2292 | if (!p4d_present(*p4d)) | |
2293 | return; | |
2294 | ||
2295 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2296 | if (!pud_present(*pud)) |
2297 | return; | |
2298 | ||
2299 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2300 | |
33f4751e | 2301 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2302 | } |
2303 | ||
71f9e58e ML |
2304 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2305 | { | |
2306 | /* | |
2307 | * If the new address isn't hpage aligned and it could previously | |
2308 | * contain an hugepage: check if we need to split an huge pmd. | |
2309 | */ | |
2310 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2311 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2312 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2313 | split_huge_pmd_address(vma, address, false, NULL); | |
2314 | } | |
2315 | ||
e1b9996b | 2316 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2317 | unsigned long start, |
2318 | unsigned long end, | |
2319 | long adjust_next) | |
2320 | { | |
71f9e58e ML |
2321 | /* Check if we need to split start first. */ |
2322 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2323 | |
71f9e58e ML |
2324 | /* Check if we need to split end next. */ |
2325 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2326 | |
2327 | /* | |
71f9e58e ML |
2328 | * If we're also updating the vma->vm_next->vm_start, |
2329 | * check if we need to split it. | |
94fcc585 AA |
2330 | */ |
2331 | if (adjust_next > 0) { | |
2332 | struct vm_area_struct *next = vma->vm_next; | |
2333 | unsigned long nstart = next->vm_start; | |
f9d86a60 | 2334 | nstart += adjust_next; |
71f9e58e | 2335 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2336 | } |
2337 | } | |
e9b61f19 | 2338 | |
906f9cdf | 2339 | static void unmap_page(struct page *page) |
e9b61f19 | 2340 | { |
013339df | 2341 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | |
c7ab0d2f | 2342 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
666e5a40 | 2343 | bool unmap_success; |
e9b61f19 KS |
2344 | |
2345 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2346 | ||
baa355fd | 2347 | if (PageAnon(page)) |
b5ff8161 | 2348 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2349 | |
666e5a40 MK |
2350 | unmap_success = try_to_unmap(page, ttu_flags); |
2351 | VM_BUG_ON_PAGE(!unmap_success, page); | |
e9b61f19 KS |
2352 | } |
2353 | ||
8cce5475 | 2354 | static void remap_page(struct page *page, unsigned int nr) |
e9b61f19 | 2355 | { |
fec89c10 | 2356 | int i; |
ace71a19 KS |
2357 | if (PageTransHuge(page)) { |
2358 | remove_migration_ptes(page, page, true); | |
2359 | } else { | |
8cce5475 | 2360 | for (i = 0; i < nr; i++) |
ace71a19 KS |
2361 | remove_migration_ptes(page + i, page + i, true); |
2362 | } | |
e9b61f19 KS |
2363 | } |
2364 | ||
94866635 | 2365 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2366 | struct lruvec *lruvec, struct list_head *list) |
2367 | { | |
94866635 AS |
2368 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2369 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2370 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2371 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2372 | |
6dbb5741 | 2373 | if (list) { |
88dcb9a3 | 2374 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2375 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2376 | get_page(tail); |
2377 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2378 | } else { |
6dbb5741 AS |
2379 | /* head is still on lru (and we have it frozen) */ |
2380 | VM_WARN_ON(!PageLRU(head)); | |
2381 | SetPageLRU(tail); | |
2382 | list_add_tail(&tail->lru, &head->lru); | |
88dcb9a3 AS |
2383 | } |
2384 | } | |
2385 | ||
8df651c7 | 2386 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2387 | struct lruvec *lruvec, struct list_head *list) |
2388 | { | |
e9b61f19 KS |
2389 | struct page *page_tail = head + tail; |
2390 | ||
8df651c7 | 2391 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2392 | |
2393 | /* | |
605ca5ed KK |
2394 | * Clone page flags before unfreezing refcount. |
2395 | * | |
2396 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2397 | * for example lock_page() which set PG_waiters. |
e9b61f19 | 2398 | */ |
e9b61f19 KS |
2399 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2400 | page_tail->flags |= (head->flags & | |
2401 | ((1L << PG_referenced) | | |
2402 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2403 | (1L << PG_swapcache) | |
e9b61f19 KS |
2404 | (1L << PG_mlocked) | |
2405 | (1L << PG_uptodate) | | |
2406 | (1L << PG_active) | | |
1899ad18 | 2407 | (1L << PG_workingset) | |
e9b61f19 | 2408 | (1L << PG_locked) | |
b8d3c4c3 | 2409 | (1L << PG_unevictable) | |
72e6afa0 CM |
2410 | #ifdef CONFIG_64BIT |
2411 | (1L << PG_arch_2) | | |
2412 | #endif | |
b8d3c4c3 | 2413 | (1L << PG_dirty))); |
e9b61f19 | 2414 | |
173d9d9f HD |
2415 | /* ->mapping in first tail page is compound_mapcount */ |
2416 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2417 | page_tail); | |
2418 | page_tail->mapping = head->mapping; | |
2419 | page_tail->index = head->index + tail; | |
2420 | ||
605ca5ed | 2421 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2422 | smp_wmb(); |
2423 | ||
605ca5ed KK |
2424 | /* |
2425 | * Clear PageTail before unfreezing page refcount. | |
2426 | * | |
2427 | * After successful get_page_unless_zero() might follow put_page() | |
2428 | * which needs correct compound_head(). | |
2429 | */ | |
e9b61f19 KS |
2430 | clear_compound_head(page_tail); |
2431 | ||
605ca5ed KK |
2432 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2433 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2434 | PageSwapCache(head))); | |
2435 | ||
e9b61f19 KS |
2436 | if (page_is_young(head)) |
2437 | set_page_young(page_tail); | |
2438 | if (page_is_idle(head)) | |
2439 | set_page_idle(page_tail); | |
2440 | ||
e9b61f19 | 2441 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2442 | |
2443 | /* | |
2444 | * always add to the tail because some iterators expect new | |
2445 | * pages to show after the currently processed elements - e.g. | |
2446 | * migrate_pages | |
2447 | */ | |
e9b61f19 | 2448 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2449 | } |
2450 | ||
baa355fd | 2451 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2452 | pgoff_t end) |
e9b61f19 KS |
2453 | { |
2454 | struct page *head = compound_head(page); | |
e9b61f19 | 2455 | struct lruvec *lruvec; |
4101196b MWO |
2456 | struct address_space *swap_cache = NULL; |
2457 | unsigned long offset = 0; | |
8cce5475 | 2458 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2459 | int i; |
e9b61f19 | 2460 | |
e9b61f19 | 2461 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2462 | split_page_memcg(head, nr); |
e9b61f19 | 2463 | |
4101196b MWO |
2464 | if (PageAnon(head) && PageSwapCache(head)) { |
2465 | swp_entry_t entry = { .val = page_private(head) }; | |
2466 | ||
2467 | offset = swp_offset(entry); | |
2468 | swap_cache = swap_address_space(entry); | |
2469 | xa_lock(&swap_cache->i_pages); | |
2470 | } | |
2471 | ||
f0953a1b | 2472 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
6168d0da | 2473 | lruvec = lock_page_lruvec(head); |
b6769834 | 2474 | |
8cce5475 | 2475 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2476 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2477 | /* Some pages can be beyond i_size: drop them from page cache */ |
2478 | if (head[i].index >= end) { | |
2d077d4b | 2479 | ClearPageDirty(head + i); |
baa355fd | 2480 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2481 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2482 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd | 2483 | put_page(head + i); |
4101196b MWO |
2484 | } else if (!PageAnon(page)) { |
2485 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2486 | head + i, 0); | |
2487 | } else if (swap_cache) { | |
2488 | __xa_store(&swap_cache->i_pages, offset + i, | |
2489 | head + i, 0); | |
baa355fd KS |
2490 | } |
2491 | } | |
e9b61f19 KS |
2492 | |
2493 | ClearPageCompound(head); | |
6168d0da | 2494 | unlock_page_lruvec(lruvec); |
b6769834 | 2495 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2496 | |
8cce5475 | 2497 | split_page_owner(head, nr); |
f7da677b | 2498 | |
baa355fd KS |
2499 | /* See comment in __split_huge_page_tail() */ |
2500 | if (PageAnon(head)) { | |
aa5dc07f | 2501 | /* Additional pin to swap cache */ |
4101196b | 2502 | if (PageSwapCache(head)) { |
38d8b4e6 | 2503 | page_ref_add(head, 2); |
4101196b MWO |
2504 | xa_unlock(&swap_cache->i_pages); |
2505 | } else { | |
38d8b4e6 | 2506 | page_ref_inc(head); |
4101196b | 2507 | } |
baa355fd | 2508 | } else { |
aa5dc07f | 2509 | /* Additional pin to page cache */ |
baa355fd | 2510 | page_ref_add(head, 2); |
b93b0163 | 2511 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2512 | } |
b6769834 | 2513 | local_irq_enable(); |
e9b61f19 | 2514 | |
8cce5475 | 2515 | remap_page(head, nr); |
e9b61f19 | 2516 | |
c4f9c701 HY |
2517 | if (PageSwapCache(head)) { |
2518 | swp_entry_t entry = { .val = page_private(head) }; | |
2519 | ||
2520 | split_swap_cluster(entry); | |
2521 | } | |
2522 | ||
8cce5475 | 2523 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2524 | struct page *subpage = head + i; |
2525 | if (subpage == page) | |
2526 | continue; | |
2527 | unlock_page(subpage); | |
2528 | ||
2529 | /* | |
2530 | * Subpages may be freed if there wasn't any mapping | |
2531 | * like if add_to_swap() is running on a lru page that | |
2532 | * had its mapping zapped. And freeing these pages | |
2533 | * requires taking the lru_lock so we do the put_page | |
2534 | * of the tail pages after the split is complete. | |
2535 | */ | |
2536 | put_page(subpage); | |
2537 | } | |
2538 | } | |
2539 | ||
b20ce5e0 KS |
2540 | int total_mapcount(struct page *page) |
2541 | { | |
86b562b6 | 2542 | int i, compound, nr, ret; |
b20ce5e0 KS |
2543 | |
2544 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2545 | ||
2546 | if (likely(!PageCompound(page))) | |
2547 | return atomic_read(&page->_mapcount) + 1; | |
2548 | ||
dd78fedd | 2549 | compound = compound_mapcount(page); |
86b562b6 | 2550 | nr = compound_nr(page); |
b20ce5e0 | 2551 | if (PageHuge(page)) |
dd78fedd KS |
2552 | return compound; |
2553 | ret = compound; | |
86b562b6 | 2554 | for (i = 0; i < nr; i++) |
b20ce5e0 | 2555 | ret += atomic_read(&page[i]._mapcount) + 1; |
dd78fedd KS |
2556 | /* File pages has compound_mapcount included in _mapcount */ |
2557 | if (!PageAnon(page)) | |
86b562b6 | 2558 | return ret - compound * nr; |
b20ce5e0 | 2559 | if (PageDoubleMap(page)) |
86b562b6 | 2560 | ret -= nr; |
b20ce5e0 KS |
2561 | return ret; |
2562 | } | |
2563 | ||
6d0a07ed AA |
2564 | /* |
2565 | * This calculates accurately how many mappings a transparent hugepage | |
2566 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2567 | * accuracy is primarily needed to know if copy-on-write faults can | |
2568 | * reuse the page and change the mapping to read-write instead of | |
2569 | * copying them. At the same time this returns the total_mapcount too. | |
2570 | * | |
2571 | * The function returns the highest mapcount any one of the subpages | |
2572 | * has. If the return value is one, even if different processes are | |
2573 | * mapping different subpages of the transparent hugepage, they can | |
2574 | * all reuse it, because each process is reusing a different subpage. | |
2575 | * | |
2576 | * The total_mapcount is instead counting all virtual mappings of the | |
2577 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2578 | * caller all mappings belong to the same "mm" and in turn the | |
2579 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2580 | * local one as no other process may be mapping any of the subpages. | |
2581 | * | |
2582 | * It would be more accurate to replace page_mapcount() with | |
2583 | * page_trans_huge_mapcount(), however we only use | |
2584 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2585 | * need full accuracy to avoid breaking page pinning, because | |
2586 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2587 | */ | |
2588 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2589 | { | |
2590 | int i, ret, _total_mapcount, mapcount; | |
2591 | ||
2592 | /* hugetlbfs shouldn't call it */ | |
2593 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2594 | ||
2595 | if (likely(!PageTransCompound(page))) { | |
2596 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2597 | if (total_mapcount) | |
2598 | *total_mapcount = mapcount; | |
2599 | return mapcount; | |
2600 | } | |
2601 | ||
2602 | page = compound_head(page); | |
2603 | ||
2604 | _total_mapcount = ret = 0; | |
65dfe3c3 | 2605 | for (i = 0; i < thp_nr_pages(page); i++) { |
6d0a07ed AA |
2606 | mapcount = atomic_read(&page[i]._mapcount) + 1; |
2607 | ret = max(ret, mapcount); | |
2608 | _total_mapcount += mapcount; | |
2609 | } | |
2610 | if (PageDoubleMap(page)) { | |
2611 | ret -= 1; | |
65dfe3c3 | 2612 | _total_mapcount -= thp_nr_pages(page); |
6d0a07ed AA |
2613 | } |
2614 | mapcount = compound_mapcount(page); | |
2615 | ret += mapcount; | |
2616 | _total_mapcount += mapcount; | |
2617 | if (total_mapcount) | |
2618 | *total_mapcount = _total_mapcount; | |
2619 | return ret; | |
2620 | } | |
2621 | ||
b8f593cd HY |
2622 | /* Racy check whether the huge page can be split */ |
2623 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2624 | { | |
2625 | int extra_pins; | |
2626 | ||
aa5dc07f | 2627 | /* Additional pins from page cache */ |
b8f593cd | 2628 | if (PageAnon(page)) |
e2333dad | 2629 | extra_pins = PageSwapCache(page) ? thp_nr_pages(page) : 0; |
b8f593cd | 2630 | else |
e2333dad | 2631 | extra_pins = thp_nr_pages(page); |
b8f593cd HY |
2632 | if (pextra_pins) |
2633 | *pextra_pins = extra_pins; | |
2634 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2635 | } | |
2636 | ||
e9b61f19 KS |
2637 | /* |
2638 | * This function splits huge page into normal pages. @page can point to any | |
2639 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2640 | * | |
2641 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2642 | * The huge page must be locked. | |
2643 | * | |
2644 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2645 | * | |
2646 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2647 | * the hugepage. | |
2648 | * | |
2649 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2650 | * they are not mapped. | |
2651 | * | |
2652 | * Returns 0 if the hugepage is split successfully. | |
2653 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2654 | * us. | |
2655 | */ | |
2656 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2657 | { | |
2658 | struct page *head = compound_head(page); | |
a8803e6c | 2659 | struct deferred_split *ds_queue = get_deferred_split_queue(head); |
baa355fd KS |
2660 | struct anon_vma *anon_vma = NULL; |
2661 | struct address_space *mapping = NULL; | |
2662 | int count, mapcount, extra_pins, ret; | |
006d3ff2 | 2663 | pgoff_t end; |
e9b61f19 | 2664 | |
cb829624 | 2665 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
a8803e6c WY |
2666 | VM_BUG_ON_PAGE(!PageLocked(head), head); |
2667 | VM_BUG_ON_PAGE(!PageCompound(head), head); | |
e9b61f19 | 2668 | |
a8803e6c | 2669 | if (PageWriteback(head)) |
59807685 HY |
2670 | return -EBUSY; |
2671 | ||
baa355fd KS |
2672 | if (PageAnon(head)) { |
2673 | /* | |
c1e8d7c6 | 2674 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2675 | * prevent the anon_vma disappearing so we first we take a |
2676 | * reference to it and then lock the anon_vma for write. This | |
2677 | * is similar to page_lock_anon_vma_read except the write lock | |
2678 | * is taken to serialise against parallel split or collapse | |
2679 | * operations. | |
2680 | */ | |
2681 | anon_vma = page_get_anon_vma(head); | |
2682 | if (!anon_vma) { | |
2683 | ret = -EBUSY; | |
2684 | goto out; | |
2685 | } | |
006d3ff2 | 2686 | end = -1; |
baa355fd KS |
2687 | mapping = NULL; |
2688 | anon_vma_lock_write(anon_vma); | |
2689 | } else { | |
2690 | mapping = head->mapping; | |
2691 | ||
2692 | /* Truncated ? */ | |
2693 | if (!mapping) { | |
2694 | ret = -EBUSY; | |
2695 | goto out; | |
2696 | } | |
2697 | ||
baa355fd KS |
2698 | anon_vma = NULL; |
2699 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2700 | |
2701 | /* | |
2702 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2703 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2704 | * which cannot be nested inside the page tree lock. So note | |
2705 | * end now: i_size itself may be changed at any moment, but | |
2706 | * head page lock is good enough to serialize the trimming. | |
2707 | */ | |
2708 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2709 | } |
e9b61f19 KS |
2710 | |
2711 | /* | |
906f9cdf | 2712 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2713 | * split PMDs |
2714 | */ | |
b8f593cd | 2715 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2716 | ret = -EBUSY; |
2717 | goto out_unlock; | |
2718 | } | |
2719 | ||
906f9cdf | 2720 | unmap_page(head); |
e9b61f19 KS |
2721 | VM_BUG_ON_PAGE(compound_mapcount(head), head); |
2722 | ||
b6769834 AS |
2723 | /* block interrupt reentry in xa_lock and spinlock */ |
2724 | local_irq_disable(); | |
baa355fd | 2725 | if (mapping) { |
aa5dc07f | 2726 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2727 | |
baa355fd | 2728 | /* |
aa5dc07f | 2729 | * Check if the head page is present in page cache. |
baa355fd KS |
2730 | * We assume all tail are present too, if head is there. |
2731 | */ | |
aa5dc07f MW |
2732 | xa_lock(&mapping->i_pages); |
2733 | if (xas_load(&xas) != head) | |
baa355fd KS |
2734 | goto fail; |
2735 | } | |
2736 | ||
0139aa7b | 2737 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2738 | spin_lock(&ds_queue->split_queue_lock); |
e9b61f19 KS |
2739 | count = page_count(head); |
2740 | mapcount = total_mapcount(head); | |
baa355fd | 2741 | if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2742 | if (!list_empty(page_deferred_list(head))) { |
364c1eeb | 2743 | ds_queue->split_queue_len--; |
9a982250 KS |
2744 | list_del(page_deferred_list(head)); |
2745 | } | |
afb97172 | 2746 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2747 | if (mapping) { |
bf9ecead MS |
2748 | int nr = thp_nr_pages(head); |
2749 | ||
a8803e6c | 2750 | if (PageSwapBacked(head)) |
57b2847d MS |
2751 | __mod_lruvec_page_state(head, NR_SHMEM_THPS, |
2752 | -nr); | |
06d3eff6 | 2753 | else |
bf9ecead MS |
2754 | __mod_lruvec_page_state(head, NR_FILE_THPS, |
2755 | -nr); | |
06d3eff6 KS |
2756 | } |
2757 | ||
b6769834 | 2758 | __split_huge_page(page, list, end); |
c4f9c701 | 2759 | ret = 0; |
e9b61f19 | 2760 | } else { |
baa355fd KS |
2761 | if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { |
2762 | pr_alert("total_mapcount: %u, page_count(): %u\n", | |
2763 | mapcount, count); | |
2764 | if (PageTail(page)) | |
2765 | dump_page(head, NULL); | |
2766 | dump_page(page, "total_mapcount(head) > 0"); | |
2767 | BUG(); | |
2768 | } | |
364c1eeb | 2769 | spin_unlock(&ds_queue->split_queue_lock); |
baa355fd | 2770 | fail: if (mapping) |
b93b0163 | 2771 | xa_unlock(&mapping->i_pages); |
b6769834 | 2772 | local_irq_enable(); |
8cce5475 | 2773 | remap_page(head, thp_nr_pages(head)); |
e9b61f19 KS |
2774 | ret = -EBUSY; |
2775 | } | |
2776 | ||
2777 | out_unlock: | |
baa355fd KS |
2778 | if (anon_vma) { |
2779 | anon_vma_unlock_write(anon_vma); | |
2780 | put_anon_vma(anon_vma); | |
2781 | } | |
2782 | if (mapping) | |
2783 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2784 | out: |
2785 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2786 | return ret; | |
2787 | } | |
9a982250 KS |
2788 | |
2789 | void free_transhuge_page(struct page *page) | |
2790 | { | |
87eaceb3 | 2791 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2792 | unsigned long flags; |
2793 | ||
364c1eeb | 2794 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2795 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2796 | ds_queue->split_queue_len--; |
9a982250 KS |
2797 | list_del(page_deferred_list(page)); |
2798 | } | |
364c1eeb | 2799 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2800 | free_compound_page(page); |
2801 | } | |
2802 | ||
2803 | void deferred_split_huge_page(struct page *page) | |
2804 | { | |
87eaceb3 YS |
2805 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2806 | #ifdef CONFIG_MEMCG | |
bcfe06bf | 2807 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 | 2808 | #endif |
9a982250 KS |
2809 | unsigned long flags; |
2810 | ||
2811 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2812 | ||
87eaceb3 YS |
2813 | /* |
2814 | * The try_to_unmap() in page reclaim path might reach here too, | |
2815 | * this may cause a race condition to corrupt deferred split queue. | |
2816 | * And, if page reclaim is already handling the same page, it is | |
2817 | * unnecessary to handle it again in shrinker. | |
2818 | * | |
2819 | * Check PageSwapCache to determine if the page is being | |
2820 | * handled by page reclaim since THP swap would add the page into | |
2821 | * swap cache before calling try_to_unmap(). | |
2822 | */ | |
2823 | if (PageSwapCache(page)) | |
2824 | return; | |
2825 | ||
364c1eeb | 2826 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2827 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2828 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2829 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2830 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2831 | #ifdef CONFIG_MEMCG |
2832 | if (memcg) | |
2bfd3637 YS |
2833 | set_shrinker_bit(memcg, page_to_nid(page), |
2834 | deferred_split_shrinker.id); | |
87eaceb3 | 2835 | #endif |
9a982250 | 2836 | } |
364c1eeb | 2837 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2838 | } |
2839 | ||
2840 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2841 | struct shrink_control *sc) | |
2842 | { | |
a3d0a918 | 2843 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2844 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2845 | |
2846 | #ifdef CONFIG_MEMCG | |
2847 | if (sc->memcg) | |
2848 | ds_queue = &sc->memcg->deferred_split_queue; | |
2849 | #endif | |
364c1eeb | 2850 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2851 | } |
2852 | ||
2853 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2854 | struct shrink_control *sc) | |
2855 | { | |
a3d0a918 | 2856 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2857 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2858 | unsigned long flags; |
2859 | LIST_HEAD(list), *pos, *next; | |
2860 | struct page *page; | |
2861 | int split = 0; | |
2862 | ||
87eaceb3 YS |
2863 | #ifdef CONFIG_MEMCG |
2864 | if (sc->memcg) | |
2865 | ds_queue = &sc->memcg->deferred_split_queue; | |
2866 | #endif | |
2867 | ||
364c1eeb | 2868 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2869 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2870 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
9a982250 KS |
2871 | page = list_entry((void *)pos, struct page, mapping); |
2872 | page = compound_head(page); | |
e3ae1953 KS |
2873 | if (get_page_unless_zero(page)) { |
2874 | list_move(page_deferred_list(page), &list); | |
2875 | } else { | |
2876 | /* We lost race with put_compound_page() */ | |
9a982250 | 2877 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2878 | ds_queue->split_queue_len--; |
9a982250 | 2879 | } |
e3ae1953 KS |
2880 | if (!--sc->nr_to_scan) |
2881 | break; | |
9a982250 | 2882 | } |
364c1eeb | 2883 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2884 | |
2885 | list_for_each_safe(pos, next, &list) { | |
2886 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2887 | if (!trylock_page(page)) |
2888 | goto next; | |
9a982250 KS |
2889 | /* split_huge_page() removes page from list on success */ |
2890 | if (!split_huge_page(page)) | |
2891 | split++; | |
2892 | unlock_page(page); | |
fa41b900 | 2893 | next: |
9a982250 KS |
2894 | put_page(page); |
2895 | } | |
2896 | ||
364c1eeb YS |
2897 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2898 | list_splice_tail(&list, &ds_queue->split_queue); | |
2899 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2900 | |
cb8d68ec KS |
2901 | /* |
2902 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2903 | * This can happen if pages were freed under us. | |
2904 | */ | |
364c1eeb | 2905 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2906 | return SHRINK_STOP; |
2907 | return split; | |
9a982250 KS |
2908 | } |
2909 | ||
2910 | static struct shrinker deferred_split_shrinker = { | |
2911 | .count_objects = deferred_split_count, | |
2912 | .scan_objects = deferred_split_scan, | |
2913 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2914 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2915 | SHRINKER_NONSLAB, | |
9a982250 | 2916 | }; |
49071d43 KS |
2917 | |
2918 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2919 | static void split_huge_pages_all(void) |
49071d43 KS |
2920 | { |
2921 | struct zone *zone; | |
2922 | struct page *page; | |
2923 | unsigned long pfn, max_zone_pfn; | |
2924 | unsigned long total = 0, split = 0; | |
2925 | ||
fa6c0231 | 2926 | pr_debug("Split all THPs\n"); |
49071d43 KS |
2927 | for_each_populated_zone(zone) { |
2928 | max_zone_pfn = zone_end_pfn(zone); | |
2929 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2930 | if (!pfn_valid(pfn)) | |
2931 | continue; | |
2932 | ||
2933 | page = pfn_to_page(pfn); | |
2934 | if (!get_page_unless_zero(page)) | |
2935 | continue; | |
2936 | ||
2937 | if (zone != page_zone(page)) | |
2938 | goto next; | |
2939 | ||
baa355fd | 2940 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2941 | goto next; |
2942 | ||
2943 | total++; | |
2944 | lock_page(page); | |
2945 | if (!split_huge_page(page)) | |
2946 | split++; | |
2947 | unlock_page(page); | |
2948 | next: | |
2949 | put_page(page); | |
fa6c0231 | 2950 | cond_resched(); |
49071d43 KS |
2951 | } |
2952 | } | |
2953 | ||
fa6c0231 ZY |
2954 | pr_debug("%lu of %lu THP split\n", split, total); |
2955 | } | |
49071d43 | 2956 | |
fa6c0231 ZY |
2957 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2958 | { | |
2959 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2960 | is_vm_hugetlb_page(vma); | |
2961 | } | |
2962 | ||
2963 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2964 | unsigned long vaddr_end) | |
2965 | { | |
2966 | int ret = 0; | |
2967 | struct task_struct *task; | |
2968 | struct mm_struct *mm; | |
2969 | unsigned long total = 0, split = 0; | |
2970 | unsigned long addr; | |
2971 | ||
2972 | vaddr_start &= PAGE_MASK; | |
2973 | vaddr_end &= PAGE_MASK; | |
2974 | ||
2975 | /* Find the task_struct from pid */ | |
2976 | rcu_read_lock(); | |
2977 | task = find_task_by_vpid(pid); | |
2978 | if (!task) { | |
2979 | rcu_read_unlock(); | |
2980 | ret = -ESRCH; | |
2981 | goto out; | |
2982 | } | |
2983 | get_task_struct(task); | |
2984 | rcu_read_unlock(); | |
2985 | ||
2986 | /* Find the mm_struct */ | |
2987 | mm = get_task_mm(task); | |
2988 | put_task_struct(task); | |
2989 | ||
2990 | if (!mm) { | |
2991 | ret = -EINVAL; | |
2992 | goto out; | |
2993 | } | |
2994 | ||
2995 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
2996 | pid, vaddr_start, vaddr_end); | |
2997 | ||
2998 | mmap_read_lock(mm); | |
2999 | /* | |
3000 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
3001 | * table filled with PTE-mapped THPs, each of which is distinct. | |
3002 | */ | |
3003 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
3004 | struct vm_area_struct *vma = find_vma(mm, addr); | |
3005 | unsigned int follflags; | |
3006 | struct page *page; | |
3007 | ||
3008 | if (!vma || addr < vma->vm_start) | |
3009 | break; | |
3010 | ||
3011 | /* skip special VMA and hugetlb VMA */ | |
3012 | if (vma_not_suitable_for_thp_split(vma)) { | |
3013 | addr = vma->vm_end; | |
3014 | continue; | |
3015 | } | |
3016 | ||
3017 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
3018 | follflags = FOLL_GET | FOLL_DUMP; | |
3019 | page = follow_page(vma, addr, follflags); | |
3020 | ||
3021 | if (IS_ERR(page)) | |
3022 | continue; | |
3023 | if (!page) | |
3024 | continue; | |
3025 | ||
3026 | if (!is_transparent_hugepage(page)) | |
3027 | goto next; | |
3028 | ||
3029 | total++; | |
3030 | if (!can_split_huge_page(compound_head(page), NULL)) | |
3031 | goto next; | |
3032 | ||
3033 | if (!trylock_page(page)) | |
3034 | goto next; | |
3035 | ||
3036 | if (!split_huge_page(page)) | |
3037 | split++; | |
3038 | ||
3039 | unlock_page(page); | |
3040 | next: | |
3041 | put_page(page); | |
3042 | cond_resched(); | |
3043 | } | |
3044 | mmap_read_unlock(mm); | |
3045 | mmput(mm); | |
3046 | ||
3047 | pr_debug("%lu of %lu THP split\n", split, total); | |
3048 | ||
3049 | out: | |
3050 | return ret; | |
49071d43 | 3051 | } |
fa6c0231 | 3052 | |
fbe37501 ZY |
3053 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
3054 | pgoff_t off_end) | |
3055 | { | |
3056 | struct filename *file; | |
3057 | struct file *candidate; | |
3058 | struct address_space *mapping; | |
3059 | int ret = -EINVAL; | |
3060 | pgoff_t index; | |
3061 | int nr_pages = 1; | |
3062 | unsigned long total = 0, split = 0; | |
3063 | ||
3064 | file = getname_kernel(file_path); | |
3065 | if (IS_ERR(file)) | |
3066 | return ret; | |
3067 | ||
3068 | candidate = file_open_name(file, O_RDONLY, 0); | |
3069 | if (IS_ERR(candidate)) | |
3070 | goto out; | |
3071 | ||
3072 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
3073 | file_path, off_start, off_end); | |
3074 | ||
3075 | mapping = candidate->f_mapping; | |
3076 | ||
3077 | for (index = off_start; index < off_end; index += nr_pages) { | |
3078 | struct page *fpage = pagecache_get_page(mapping, index, | |
3079 | FGP_ENTRY | FGP_HEAD, 0); | |
3080 | ||
3081 | nr_pages = 1; | |
3082 | if (xa_is_value(fpage) || !fpage) | |
3083 | continue; | |
3084 | ||
3085 | if (!is_transparent_hugepage(fpage)) | |
3086 | goto next; | |
3087 | ||
3088 | total++; | |
3089 | nr_pages = thp_nr_pages(fpage); | |
3090 | ||
3091 | if (!trylock_page(fpage)) | |
3092 | goto next; | |
3093 | ||
3094 | if (!split_huge_page(fpage)) | |
3095 | split++; | |
3096 | ||
3097 | unlock_page(fpage); | |
3098 | next: | |
3099 | put_page(fpage); | |
3100 | cond_resched(); | |
3101 | } | |
3102 | ||
3103 | filp_close(candidate, NULL); | |
3104 | ret = 0; | |
3105 | ||
3106 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3107 | out: | |
3108 | putname(file); | |
3109 | return ret; | |
3110 | } | |
3111 | ||
fa6c0231 ZY |
3112 | #define MAX_INPUT_BUF_SZ 255 |
3113 | ||
3114 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3115 | size_t count, loff_t *ppops) | |
3116 | { | |
3117 | static DEFINE_MUTEX(split_debug_mutex); | |
3118 | ssize_t ret; | |
fbe37501 ZY |
3119 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3120 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3121 | int pid; |
3122 | unsigned long vaddr_start, vaddr_end; | |
3123 | ||
3124 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3125 | if (ret) | |
3126 | return ret; | |
3127 | ||
3128 | ret = -EFAULT; | |
3129 | ||
3130 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3131 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3132 | goto out; | |
3133 | ||
3134 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3135 | |
3136 | if (input_buf[0] == '/') { | |
3137 | char *tok; | |
3138 | char *buf = input_buf; | |
3139 | char file_path[MAX_INPUT_BUF_SZ]; | |
3140 | pgoff_t off_start = 0, off_end = 0; | |
3141 | size_t input_len = strlen(input_buf); | |
3142 | ||
3143 | tok = strsep(&buf, ","); | |
3144 | if (tok) { | |
3145 | strncpy(file_path, tok, MAX_INPUT_BUF_SZ); | |
3146 | } else { | |
3147 | ret = -EINVAL; | |
3148 | goto out; | |
3149 | } | |
3150 | ||
3151 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3152 | if (ret != 2) { | |
3153 | ret = -EINVAL; | |
3154 | goto out; | |
3155 | } | |
3156 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3157 | if (!ret) | |
3158 | ret = input_len; | |
3159 | ||
3160 | goto out; | |
3161 | } | |
3162 | ||
fa6c0231 ZY |
3163 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3164 | if (ret == 1 && pid == 1) { | |
3165 | split_huge_pages_all(); | |
3166 | ret = strlen(input_buf); | |
3167 | goto out; | |
3168 | } else if (ret != 3) { | |
3169 | ret = -EINVAL; | |
3170 | goto out; | |
3171 | } | |
3172 | ||
3173 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3174 | if (!ret) | |
3175 | ret = strlen(input_buf); | |
3176 | out: | |
3177 | mutex_unlock(&split_debug_mutex); | |
3178 | return ret; | |
3179 | ||
3180 | } | |
3181 | ||
3182 | static const struct file_operations split_huge_pages_fops = { | |
3183 | .owner = THIS_MODULE, | |
3184 | .write = split_huge_pages_write, | |
3185 | .llseek = no_llseek, | |
3186 | }; | |
49071d43 KS |
3187 | |
3188 | static int __init split_huge_pages_debugfs(void) | |
3189 | { | |
d9f7979c GKH |
3190 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3191 | &split_huge_pages_fops); | |
49071d43 KS |
3192 | return 0; |
3193 | } | |
3194 | late_initcall(split_huge_pages_debugfs); | |
3195 | #endif | |
616b8371 ZY |
3196 | |
3197 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
3198 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
3199 | struct page *page) | |
3200 | { | |
3201 | struct vm_area_struct *vma = pvmw->vma; | |
3202 | struct mm_struct *mm = vma->vm_mm; | |
3203 | unsigned long address = pvmw->address; | |
3204 | pmd_t pmdval; | |
3205 | swp_entry_t entry; | |
ab6e3d09 | 3206 | pmd_t pmdswp; |
616b8371 ZY |
3207 | |
3208 | if (!(pvmw->pmd && !pvmw->pte)) | |
3209 | return; | |
3210 | ||
616b8371 | 3211 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3212 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
616b8371 ZY |
3213 | if (pmd_dirty(pmdval)) |
3214 | set_page_dirty(page); | |
3215 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
3216 | pmdswp = swp_entry_to_pmd(entry); |
3217 | if (pmd_soft_dirty(pmdval)) | |
3218 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3219 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
3220 | page_remove_rmap(page, true); |
3221 | put_page(page); | |
616b8371 ZY |
3222 | } |
3223 | ||
3224 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3225 | { | |
3226 | struct vm_area_struct *vma = pvmw->vma; | |
3227 | struct mm_struct *mm = vma->vm_mm; | |
3228 | unsigned long address = pvmw->address; | |
3229 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
3230 | pmd_t pmde; | |
3231 | swp_entry_t entry; | |
3232 | ||
3233 | if (!(pvmw->pmd && !pvmw->pte)) | |
3234 | return; | |
3235 | ||
3236 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3237 | get_page(new); | |
3238 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
3239 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3240 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 3241 | if (is_write_migration_entry(entry)) |
f55e1014 | 3242 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
3243 | |
3244 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
3245 | if (PageAnon(new)) |
3246 | page_add_anon_rmap(new, vma, mmun_start, true); | |
3247 | else | |
3248 | page_add_file_rmap(new, true); | |
616b8371 | 3249 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 3250 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
3251 | mlock_vma_page(new); |
3252 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
3253 | } | |
3254 | #endif |