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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; |
3b77e8c8 | 65 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 66 | |
7635d9cb MH |
67 | bool transparent_hugepage_enabled(struct vm_area_struct *vma) |
68 | { | |
c0630669 YS |
69 | /* The addr is used to check if the vma size fits */ |
70 | unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; | |
71 | ||
72 | if (!transhuge_vma_suitable(vma, addr)) | |
73 | return false; | |
7635d9cb MH |
74 | if (vma_is_anonymous(vma)) |
75 | return __transparent_hugepage_enabled(vma); | |
c0630669 YS |
76 | if (vma_is_shmem(vma)) |
77 | return shmem_huge_enabled(vma); | |
7635d9cb MH |
78 | |
79 | return false; | |
80 | } | |
81 | ||
aaa9705b | 82 | static bool get_huge_zero_page(void) |
97ae1749 KS |
83 | { |
84 | struct page *zero_page; | |
85 | retry: | |
86 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 87 | return true; |
97ae1749 KS |
88 | |
89 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 90 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
91 | if (!zero_page) { |
92 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 93 | return false; |
d8a8e1f0 KS |
94 | } |
95 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 96 | preempt_disable(); |
5918d10a | 97 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 98 | preempt_enable(); |
5ddacbe9 | 99 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
100 | goto retry; |
101 | } | |
3b77e8c8 | 102 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
103 | |
104 | /* We take additional reference here. It will be put back by shrinker */ | |
105 | atomic_set(&huge_zero_refcount, 2); | |
106 | preempt_enable(); | |
aaa9705b | 107 | return true; |
4a6c1297 KS |
108 | } |
109 | ||
6fcb52a5 | 110 | static void put_huge_zero_page(void) |
4a6c1297 | 111 | { |
97ae1749 KS |
112 | /* |
113 | * Counter should never go to zero here. Only shrinker can put | |
114 | * last reference. | |
115 | */ | |
116 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
117 | } |
118 | ||
6fcb52a5 AL |
119 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
120 | { | |
121 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
122 | return READ_ONCE(huge_zero_page); | |
123 | ||
124 | if (!get_huge_zero_page()) | |
125 | return NULL; | |
126 | ||
127 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
128 | put_huge_zero_page(); | |
129 | ||
130 | return READ_ONCE(huge_zero_page); | |
131 | } | |
132 | ||
133 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
134 | { | |
135 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
136 | put_huge_zero_page(); | |
137 | } | |
138 | ||
48896466 GC |
139 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
140 | struct shrink_control *sc) | |
4a6c1297 | 141 | { |
48896466 GC |
142 | /* we can free zero page only if last reference remains */ |
143 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
144 | } | |
97ae1749 | 145 | |
48896466 GC |
146 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
147 | struct shrink_control *sc) | |
148 | { | |
97ae1749 | 149 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
150 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
151 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 152 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 153 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 154 | return HPAGE_PMD_NR; |
97ae1749 KS |
155 | } |
156 | ||
157 | return 0; | |
4a6c1297 KS |
158 | } |
159 | ||
97ae1749 | 160 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
161 | .count_objects = shrink_huge_zero_page_count, |
162 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
163 | .seeks = DEFAULT_SEEKS, |
164 | }; | |
165 | ||
71e3aac0 | 166 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
167 | static ssize_t enabled_show(struct kobject *kobj, |
168 | struct kobj_attribute *attr, char *buf) | |
169 | { | |
bfb0ffeb JP |
170 | const char *output; |
171 | ||
444eb2a4 | 172 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
173 | output = "[always] madvise never"; |
174 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
175 | &transparent_hugepage_flags)) | |
176 | output = "always [madvise] never"; | |
444eb2a4 | 177 | else |
bfb0ffeb JP |
178 | output = "always madvise [never]"; |
179 | ||
180 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 181 | } |
444eb2a4 | 182 | |
71e3aac0 AA |
183 | static ssize_t enabled_store(struct kobject *kobj, |
184 | struct kobj_attribute *attr, | |
185 | const char *buf, size_t count) | |
186 | { | |
21440d7e | 187 | ssize_t ret = count; |
ba76149f | 188 | |
f42f2552 | 189 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
190 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
191 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 192 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
193 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
194 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 195 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
196 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
197 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
198 | } else | |
199 | ret = -EINVAL; | |
ba76149f AA |
200 | |
201 | if (ret > 0) { | |
b46e756f | 202 | int err = start_stop_khugepaged(); |
ba76149f AA |
203 | if (err) |
204 | ret = err; | |
205 | } | |
ba76149f | 206 | return ret; |
71e3aac0 AA |
207 | } |
208 | static struct kobj_attribute enabled_attr = | |
209 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
210 | ||
b46e756f | 211 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
212 | struct kobj_attribute *attr, char *buf, |
213 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 214 | { |
bfb0ffeb JP |
215 | return sysfs_emit(buf, "%d\n", |
216 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 217 | } |
e27e6151 | 218 | |
b46e756f | 219 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
220 | struct kobj_attribute *attr, |
221 | const char *buf, size_t count, | |
222 | enum transparent_hugepage_flag flag) | |
223 | { | |
e27e6151 BH |
224 | unsigned long value; |
225 | int ret; | |
226 | ||
227 | ret = kstrtoul(buf, 10, &value); | |
228 | if (ret < 0) | |
229 | return ret; | |
230 | if (value > 1) | |
231 | return -EINVAL; | |
232 | ||
233 | if (value) | |
71e3aac0 | 234 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 235 | else |
71e3aac0 | 236 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
237 | |
238 | return count; | |
239 | } | |
240 | ||
71e3aac0 AA |
241 | static ssize_t defrag_show(struct kobject *kobj, |
242 | struct kobj_attribute *attr, char *buf) | |
243 | { | |
bfb0ffeb JP |
244 | const char *output; |
245 | ||
246 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
247 | &transparent_hugepage_flags)) | |
248 | output = "[always] defer defer+madvise madvise never"; | |
249 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
250 | &transparent_hugepage_flags)) | |
251 | output = "always [defer] defer+madvise madvise never"; | |
252 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
253 | &transparent_hugepage_flags)) | |
254 | output = "always defer [defer+madvise] madvise never"; | |
255 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
256 | &transparent_hugepage_flags)) | |
257 | output = "always defer defer+madvise [madvise] never"; | |
258 | else | |
259 | output = "always defer defer+madvise madvise [never]"; | |
260 | ||
261 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 262 | } |
21440d7e | 263 | |
71e3aac0 AA |
264 | static ssize_t defrag_store(struct kobject *kobj, |
265 | struct kobj_attribute *attr, | |
266 | const char *buf, size_t count) | |
267 | { | |
f42f2552 | 268 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
269 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
270 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
271 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
272 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 273 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
274 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
275 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
276 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
277 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 278 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
279 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
280 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
281 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
282 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 283 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
284 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
285 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
286 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
287 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 288 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
289 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
290 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
291 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
292 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
293 | } else | |
294 | return -EINVAL; | |
295 | ||
296 | return count; | |
71e3aac0 AA |
297 | } |
298 | static struct kobj_attribute defrag_attr = | |
299 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
300 | ||
79da5407 | 301 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 302 | struct kobj_attribute *attr, char *buf) |
79da5407 | 303 | { |
b46e756f | 304 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 305 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
306 | } |
307 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
308 | struct kobj_attribute *attr, const char *buf, size_t count) | |
309 | { | |
b46e756f | 310 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
311 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
312 | } | |
313 | static struct kobj_attribute use_zero_page_attr = | |
314 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
315 | |
316 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 317 | struct kobj_attribute *attr, char *buf) |
49920d28 | 318 | { |
ae7a927d | 319 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
320 | } |
321 | static struct kobj_attribute hpage_pmd_size_attr = | |
322 | __ATTR_RO(hpage_pmd_size); | |
323 | ||
71e3aac0 AA |
324 | static struct attribute *hugepage_attr[] = { |
325 | &enabled_attr.attr, | |
326 | &defrag_attr.attr, | |
79da5407 | 327 | &use_zero_page_attr.attr, |
49920d28 | 328 | &hpage_pmd_size_attr.attr, |
396bcc52 | 329 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 330 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
331 | #endif |
332 | NULL, | |
333 | }; | |
334 | ||
8aa95a21 | 335 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 336 | .attrs = hugepage_attr, |
ba76149f AA |
337 | }; |
338 | ||
569e5590 | 339 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 340 | { |
71e3aac0 AA |
341 | int err; |
342 | ||
569e5590 SL |
343 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
344 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 345 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 346 | return -ENOMEM; |
ba76149f AA |
347 | } |
348 | ||
569e5590 | 349 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 350 | if (err) { |
ae3a8c1c | 351 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 352 | goto delete_obj; |
ba76149f AA |
353 | } |
354 | ||
569e5590 | 355 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 356 | if (err) { |
ae3a8c1c | 357 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 358 | goto remove_hp_group; |
ba76149f | 359 | } |
569e5590 SL |
360 | |
361 | return 0; | |
362 | ||
363 | remove_hp_group: | |
364 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
365 | delete_obj: | |
366 | kobject_put(*hugepage_kobj); | |
367 | return err; | |
368 | } | |
369 | ||
370 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
371 | { | |
372 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
373 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
374 | kobject_put(hugepage_kobj); | |
375 | } | |
376 | #else | |
377 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
378 | { | |
379 | return 0; | |
380 | } | |
381 | ||
382 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
383 | { | |
384 | } | |
385 | #endif /* CONFIG_SYSFS */ | |
386 | ||
387 | static int __init hugepage_init(void) | |
388 | { | |
389 | int err; | |
390 | struct kobject *hugepage_kobj; | |
391 | ||
392 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
393 | /* |
394 | * Hardware doesn't support hugepages, hence disable | |
395 | * DAX PMD support. | |
396 | */ | |
397 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
398 | return -EINVAL; |
399 | } | |
400 | ||
ff20c2e0 KS |
401 | /* |
402 | * hugepages can't be allocated by the buddy allocator | |
403 | */ | |
404 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
405 | /* | |
406 | * we use page->mapping and page->index in second tail page | |
407 | * as list_head: assuming THP order >= 2 | |
408 | */ | |
409 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
410 | ||
569e5590 SL |
411 | err = hugepage_init_sysfs(&hugepage_kobj); |
412 | if (err) | |
65ebb64f | 413 | goto err_sysfs; |
ba76149f | 414 | |
b46e756f | 415 | err = khugepaged_init(); |
ba76149f | 416 | if (err) |
65ebb64f | 417 | goto err_slab; |
ba76149f | 418 | |
65ebb64f KS |
419 | err = register_shrinker(&huge_zero_page_shrinker); |
420 | if (err) | |
421 | goto err_hzp_shrinker; | |
9a982250 KS |
422 | err = register_shrinker(&deferred_split_shrinker); |
423 | if (err) | |
424 | goto err_split_shrinker; | |
97ae1749 | 425 | |
97562cd2 RR |
426 | /* |
427 | * By default disable transparent hugepages on smaller systems, | |
428 | * where the extra memory used could hurt more than TLB overhead | |
429 | * is likely to save. The admin can still enable it through /sys. | |
430 | */ | |
ca79b0c2 | 431 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 432 | transparent_hugepage_flags = 0; |
79553da2 KS |
433 | return 0; |
434 | } | |
97562cd2 | 435 | |
79553da2 | 436 | err = start_stop_khugepaged(); |
65ebb64f KS |
437 | if (err) |
438 | goto err_khugepaged; | |
ba76149f | 439 | |
569e5590 | 440 | return 0; |
65ebb64f | 441 | err_khugepaged: |
9a982250 KS |
442 | unregister_shrinker(&deferred_split_shrinker); |
443 | err_split_shrinker: | |
65ebb64f KS |
444 | unregister_shrinker(&huge_zero_page_shrinker); |
445 | err_hzp_shrinker: | |
b46e756f | 446 | khugepaged_destroy(); |
65ebb64f | 447 | err_slab: |
569e5590 | 448 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 449 | err_sysfs: |
ba76149f | 450 | return err; |
71e3aac0 | 451 | } |
a64fb3cd | 452 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
453 | |
454 | static int __init setup_transparent_hugepage(char *str) | |
455 | { | |
456 | int ret = 0; | |
457 | if (!str) | |
458 | goto out; | |
459 | if (!strcmp(str, "always")) { | |
460 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
461 | &transparent_hugepage_flags); | |
462 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
463 | &transparent_hugepage_flags); | |
464 | ret = 1; | |
465 | } else if (!strcmp(str, "madvise")) { | |
466 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
467 | &transparent_hugepage_flags); | |
468 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
469 | &transparent_hugepage_flags); | |
470 | ret = 1; | |
471 | } else if (!strcmp(str, "never")) { | |
472 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
473 | &transparent_hugepage_flags); | |
474 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
475 | &transparent_hugepage_flags); | |
476 | ret = 1; | |
477 | } | |
478 | out: | |
479 | if (!ret) | |
ae3a8c1c | 480 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
481 | return ret; |
482 | } | |
483 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
484 | ||
f55e1014 | 485 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 486 | { |
f55e1014 | 487 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
488 | pmd = pmd_mkwrite(pmd); |
489 | return pmd; | |
490 | } | |
491 | ||
87eaceb3 YS |
492 | #ifdef CONFIG_MEMCG |
493 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 494 | { |
bcfe06bf | 495 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 YS |
496 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); |
497 | ||
498 | if (memcg) | |
499 | return &memcg->deferred_split_queue; | |
500 | else | |
501 | return &pgdat->deferred_split_queue; | |
9a982250 | 502 | } |
87eaceb3 YS |
503 | #else |
504 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
505 | { | |
506 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
507 | ||
508 | return &pgdat->deferred_split_queue; | |
509 | } | |
510 | #endif | |
9a982250 KS |
511 | |
512 | void prep_transhuge_page(struct page *page) | |
513 | { | |
514 | /* | |
515 | * we use page->mapping and page->indexlru in second tail page | |
516 | * as list_head: assuming THP order >= 2 | |
517 | */ | |
9a982250 KS |
518 | |
519 | INIT_LIST_HEAD(page_deferred_list(page)); | |
520 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
521 | } | |
522 | ||
005ba37c SC |
523 | bool is_transparent_hugepage(struct page *page) |
524 | { | |
525 | if (!PageCompound(page)) | |
fa1f68cc | 526 | return false; |
005ba37c SC |
527 | |
528 | page = compound_head(page); | |
529 | return is_huge_zero_page(page) || | |
530 | page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; | |
531 | } | |
532 | EXPORT_SYMBOL_GPL(is_transparent_hugepage); | |
533 | ||
97d3d0f9 KS |
534 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
535 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
536 | loff_t off, unsigned long flags, unsigned long size) |
537 | { | |
74d2fad1 TK |
538 | loff_t off_end = off + len; |
539 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 540 | unsigned long len_pad, ret; |
74d2fad1 TK |
541 | |
542 | if (off_end <= off_align || (off_end - off_align) < size) | |
543 | return 0; | |
544 | ||
545 | len_pad = len + size; | |
546 | if (len_pad < len || (off + len_pad) < off) | |
547 | return 0; | |
548 | ||
97d3d0f9 | 549 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 550 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
551 | |
552 | /* | |
553 | * The failure might be due to length padding. The caller will retry | |
554 | * without the padding. | |
555 | */ | |
556 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
557 | return 0; |
558 | ||
97d3d0f9 KS |
559 | /* |
560 | * Do not try to align to THP boundary if allocation at the address | |
561 | * hint succeeds. | |
562 | */ | |
563 | if (ret == addr) | |
564 | return addr; | |
565 | ||
566 | ret += (off - ret) & (size - 1); | |
567 | return ret; | |
74d2fad1 TK |
568 | } |
569 | ||
570 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
571 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
572 | { | |
97d3d0f9 | 573 | unsigned long ret; |
74d2fad1 TK |
574 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
575 | ||
74d2fad1 TK |
576 | if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD)) |
577 | goto out; | |
578 | ||
97d3d0f9 KS |
579 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
580 | if (ret) | |
581 | return ret; | |
582 | out: | |
74d2fad1 TK |
583 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
584 | } | |
585 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
586 | ||
2b740303 SJ |
587 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
588 | struct page *page, gfp_t gfp) | |
71e3aac0 | 589 | { |
82b0f8c3 | 590 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 591 | pgtable_t pgtable; |
82b0f8c3 | 592 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 593 | vm_fault_t ret = 0; |
71e3aac0 | 594 | |
309381fe | 595 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 596 | |
d9eb1ea2 | 597 | if (mem_cgroup_charge(page, vma->vm_mm, gfp)) { |
6b251fc9 AA |
598 | put_page(page); |
599 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 600 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
601 | return VM_FAULT_FALLBACK; |
602 | } | |
9d82c694 | 603 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 604 | |
4cf58924 | 605 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 606 | if (unlikely(!pgtable)) { |
6b31d595 MH |
607 | ret = VM_FAULT_OOM; |
608 | goto release; | |
00501b53 | 609 | } |
71e3aac0 | 610 | |
c79b57e4 | 611 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
612 | /* |
613 | * The memory barrier inside __SetPageUptodate makes sure that | |
614 | * clear_huge_page writes become visible before the set_pmd_at() | |
615 | * write. | |
616 | */ | |
71e3aac0 AA |
617 | __SetPageUptodate(page); |
618 | ||
82b0f8c3 JK |
619 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
620 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 621 | goto unlock_release; |
71e3aac0 AA |
622 | } else { |
623 | pmd_t entry; | |
6b251fc9 | 624 | |
6b31d595 MH |
625 | ret = check_stable_address_space(vma->vm_mm); |
626 | if (ret) | |
627 | goto unlock_release; | |
628 | ||
6b251fc9 AA |
629 | /* Deliver the page fault to userland */ |
630 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 631 | spin_unlock(vmf->ptl); |
6b251fc9 | 632 | put_page(page); |
bae473a4 | 633 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
634 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
635 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
636 | return ret; | |
6b251fc9 AA |
637 | } |
638 | ||
3122359a | 639 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 640 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 641 | page_add_new_anon_rmap(page, vma, haddr, true); |
b518154e | 642 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
643 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
644 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 645 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 646 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 647 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 648 | spin_unlock(vmf->ptl); |
6b251fc9 | 649 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 650 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
651 | } |
652 | ||
aa2e878e | 653 | return 0; |
6b31d595 MH |
654 | unlock_release: |
655 | spin_unlock(vmf->ptl); | |
656 | release: | |
657 | if (pgtable) | |
658 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
659 | put_page(page); |
660 | return ret; | |
661 | ||
71e3aac0 AA |
662 | } |
663 | ||
444eb2a4 | 664 | /* |
21440d7e DR |
665 | * always: directly stall for all thp allocations |
666 | * defer: wake kswapd and fail if not immediately available | |
667 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
668 | * fail if not immediately available | |
669 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
670 | * available | |
671 | * never: never stall for any thp allocation | |
444eb2a4 | 672 | */ |
164cc4fe | 673 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 674 | { |
164cc4fe | 675 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 676 | |
ac79f78d | 677 | /* Always do synchronous compaction */ |
a8282608 AA |
678 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
679 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
680 | |
681 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 682 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 683 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
684 | |
685 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 686 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
687 | return GFP_TRANSHUGE_LIGHT | |
688 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
689 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
690 | |
691 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 692 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
693 | return GFP_TRANSHUGE_LIGHT | |
694 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 695 | |
19deb769 | 696 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
697 | } |
698 | ||
c4088ebd | 699 | /* Caller must hold page table lock. */ |
2efeb8da | 700 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 701 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 702 | struct page *zero_page) |
fc9fe822 KS |
703 | { |
704 | pmd_t entry; | |
7c414164 | 705 | if (!pmd_none(*pmd)) |
2efeb8da | 706 | return; |
5918d10a | 707 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 708 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
709 | if (pgtable) |
710 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 711 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 712 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
713 | } |
714 | ||
2b740303 | 715 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 716 | { |
82b0f8c3 | 717 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 718 | gfp_t gfp; |
71e3aac0 | 719 | struct page *page; |
82b0f8c3 | 720 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 721 | |
43675e6f | 722 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 723 | return VM_FAULT_FALLBACK; |
128ec037 KS |
724 | if (unlikely(anon_vma_prepare(vma))) |
725 | return VM_FAULT_OOM; | |
6d50e60c | 726 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 727 | return VM_FAULT_OOM; |
82b0f8c3 | 728 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 729 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
730 | transparent_hugepage_use_zero_page()) { |
731 | pgtable_t pgtable; | |
732 | struct page *zero_page; | |
2b740303 | 733 | vm_fault_t ret; |
4cf58924 | 734 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 735 | if (unlikely(!pgtable)) |
ba76149f | 736 | return VM_FAULT_OOM; |
6fcb52a5 | 737 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 738 | if (unlikely(!zero_page)) { |
bae473a4 | 739 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 740 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 741 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 742 | } |
82b0f8c3 | 743 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 744 | ret = 0; |
82b0f8c3 | 745 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
746 | ret = check_stable_address_space(vma->vm_mm); |
747 | if (ret) { | |
748 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 749 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 750 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 751 | spin_unlock(vmf->ptl); |
bfe8cc1d | 752 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 753 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
754 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
755 | } else { | |
bae473a4 | 756 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 757 | haddr, vmf->pmd, zero_page); |
fca40573 | 758 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 759 | spin_unlock(vmf->ptl); |
6b251fc9 | 760 | } |
bfe8cc1d | 761 | } else { |
82b0f8c3 | 762 | spin_unlock(vmf->ptl); |
bae473a4 | 763 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 764 | } |
6b251fc9 | 765 | return ret; |
71e3aac0 | 766 | } |
164cc4fe | 767 | gfp = vma_thp_gfp_mask(vma); |
19deb769 | 768 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
769 | if (unlikely(!page)) { |
770 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 771 | return VM_FAULT_FALLBACK; |
128ec037 | 772 | } |
9a982250 | 773 | prep_transhuge_page(page); |
82b0f8c3 | 774 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
775 | } |
776 | ||
ae18d6dc | 777 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
778 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
779 | pgtable_t pgtable) | |
5cad465d MW |
780 | { |
781 | struct mm_struct *mm = vma->vm_mm; | |
782 | pmd_t entry; | |
783 | spinlock_t *ptl; | |
784 | ||
785 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
786 | if (!pmd_none(*pmd)) { |
787 | if (write) { | |
788 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
789 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
790 | goto out_unlock; | |
791 | } | |
792 | entry = pmd_mkyoung(*pmd); | |
793 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
794 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
795 | update_mmu_cache_pmd(vma, addr, pmd); | |
796 | } | |
797 | ||
798 | goto out_unlock; | |
799 | } | |
800 | ||
f25748e3 DW |
801 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
802 | if (pfn_t_devmap(pfn)) | |
803 | entry = pmd_mkdevmap(entry); | |
01871e59 | 804 | if (write) { |
f55e1014 LT |
805 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
806 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 807 | } |
3b6521f5 OH |
808 | |
809 | if (pgtable) { | |
810 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 811 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 812 | pgtable = NULL; |
3b6521f5 OH |
813 | } |
814 | ||
01871e59 RZ |
815 | set_pmd_at(mm, addr, pmd, entry); |
816 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
817 | |
818 | out_unlock: | |
5cad465d | 819 | spin_unlock(ptl); |
c6f3c5ee AK |
820 | if (pgtable) |
821 | pte_free(mm, pgtable); | |
5cad465d MW |
822 | } |
823 | ||
9a9731b1 THV |
824 | /** |
825 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
826 | * @vmf: Structure describing the fault | |
827 | * @pfn: pfn to insert | |
828 | * @pgprot: page protection to use | |
829 | * @write: whether it's a write fault | |
830 | * | |
831 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
832 | * also consult the vmf_insert_mixed_prot() documentation when | |
833 | * @pgprot != @vmf->vma->vm_page_prot. | |
834 | * | |
835 | * Return: vm_fault_t value. | |
836 | */ | |
837 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
838 | pgprot_t pgprot, bool write) | |
5cad465d | 839 | { |
fce86ff5 DW |
840 | unsigned long addr = vmf->address & PMD_MASK; |
841 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 842 | pgtable_t pgtable = NULL; |
fce86ff5 | 843 | |
5cad465d MW |
844 | /* |
845 | * If we had pmd_special, we could avoid all these restrictions, | |
846 | * but we need to be consistent with PTEs and architectures that | |
847 | * can't support a 'special' bit. | |
848 | */ | |
e1fb4a08 DJ |
849 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
850 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
851 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
852 | (VM_PFNMAP|VM_MIXEDMAP)); | |
853 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
854 | |
855 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
856 | return VM_FAULT_SIGBUS; | |
308a047c | 857 | |
3b6521f5 | 858 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 859 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
860 | if (!pgtable) |
861 | return VM_FAULT_OOM; | |
862 | } | |
863 | ||
308a047c BP |
864 | track_pfn_insert(vma, &pgprot, pfn); |
865 | ||
fce86ff5 | 866 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 867 | return VM_FAULT_NOPAGE; |
5cad465d | 868 | } |
9a9731b1 | 869 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 870 | |
a00cc7d9 | 871 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 872 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 873 | { |
f55e1014 | 874 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
875 | pud = pud_mkwrite(pud); |
876 | return pud; | |
877 | } | |
878 | ||
879 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
880 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
881 | { | |
882 | struct mm_struct *mm = vma->vm_mm; | |
883 | pud_t entry; | |
884 | spinlock_t *ptl; | |
885 | ||
886 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
887 | if (!pud_none(*pud)) { |
888 | if (write) { | |
889 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
890 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
891 | goto out_unlock; | |
892 | } | |
893 | entry = pud_mkyoung(*pud); | |
894 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
895 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
896 | update_mmu_cache_pud(vma, addr, pud); | |
897 | } | |
898 | goto out_unlock; | |
899 | } | |
900 | ||
a00cc7d9 MW |
901 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
902 | if (pfn_t_devmap(pfn)) | |
903 | entry = pud_mkdevmap(entry); | |
904 | if (write) { | |
f55e1014 LT |
905 | entry = pud_mkyoung(pud_mkdirty(entry)); |
906 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
907 | } |
908 | set_pud_at(mm, addr, pud, entry); | |
909 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
910 | |
911 | out_unlock: | |
a00cc7d9 MW |
912 | spin_unlock(ptl); |
913 | } | |
914 | ||
9a9731b1 THV |
915 | /** |
916 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
917 | * @vmf: Structure describing the fault | |
918 | * @pfn: pfn to insert | |
919 | * @pgprot: page protection to use | |
920 | * @write: whether it's a write fault | |
921 | * | |
922 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
923 | * also consult the vmf_insert_mixed_prot() documentation when | |
924 | * @pgprot != @vmf->vma->vm_page_prot. | |
925 | * | |
926 | * Return: vm_fault_t value. | |
927 | */ | |
928 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
929 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 930 | { |
fce86ff5 DW |
931 | unsigned long addr = vmf->address & PUD_MASK; |
932 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 933 | |
a00cc7d9 MW |
934 | /* |
935 | * If we had pud_special, we could avoid all these restrictions, | |
936 | * but we need to be consistent with PTEs and architectures that | |
937 | * can't support a 'special' bit. | |
938 | */ | |
62ec0d8c DJ |
939 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
940 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
941 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
942 | (VM_PFNMAP|VM_MIXEDMAP)); | |
943 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
944 | |
945 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
946 | return VM_FAULT_SIGBUS; | |
947 | ||
948 | track_pfn_insert(vma, &pgprot, pfn); | |
949 | ||
fce86ff5 | 950 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
951 | return VM_FAULT_NOPAGE; |
952 | } | |
9a9731b1 | 953 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
954 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
955 | ||
3565fce3 | 956 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 957 | pmd_t *pmd, int flags) |
3565fce3 DW |
958 | { |
959 | pmd_t _pmd; | |
960 | ||
a8f97366 KS |
961 | _pmd = pmd_mkyoung(*pmd); |
962 | if (flags & FOLL_WRITE) | |
963 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 964 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 965 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
966 | update_mmu_cache_pmd(vma, addr, pmd); |
967 | } | |
968 | ||
969 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 970 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
971 | { |
972 | unsigned long pfn = pmd_pfn(*pmd); | |
973 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
974 | struct page *page; |
975 | ||
976 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
977 | ||
8310d48b KF |
978 | /* |
979 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
980 | * not be in this function with `flags & FOLL_COW` set. | |
981 | */ | |
982 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
983 | ||
3faa52c0 JH |
984 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
985 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
986 | (FOLL_PIN | FOLL_GET))) | |
987 | return NULL; | |
988 | ||
f6f37321 | 989 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
990 | return NULL; |
991 | ||
992 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
993 | /* pass */; | |
994 | else | |
995 | return NULL; | |
996 | ||
997 | if (flags & FOLL_TOUCH) | |
a8f97366 | 998 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
999 | |
1000 | /* | |
1001 | * device mapped pages can only be returned if the | |
1002 | * caller will manage the page reference count. | |
1003 | */ | |
3faa52c0 | 1004 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1005 | return ERR_PTR(-EEXIST); |
1006 | ||
1007 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1008 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1009 | if (!*pgmap) | |
3565fce3 DW |
1010 | return ERR_PTR(-EFAULT); |
1011 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1012 | if (!try_grab_page(page, flags)) |
1013 | page = ERR_PTR(-ENOMEM); | |
3565fce3 DW |
1014 | |
1015 | return page; | |
1016 | } | |
1017 | ||
71e3aac0 AA |
1018 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1019 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
1020 | struct vm_area_struct *vma) | |
1021 | { | |
c4088ebd | 1022 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1023 | struct page *src_page; |
1024 | pmd_t pmd; | |
12c9d70b | 1025 | pgtable_t pgtable = NULL; |
628d47ce | 1026 | int ret = -ENOMEM; |
71e3aac0 | 1027 | |
628d47ce KS |
1028 | /* Skip if can be re-fill on fault */ |
1029 | if (!vma_is_anonymous(vma)) | |
1030 | return 0; | |
1031 | ||
4cf58924 | 1032 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1033 | if (unlikely(!pgtable)) |
1034 | goto out; | |
71e3aac0 | 1035 | |
c4088ebd KS |
1036 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1037 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1038 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1039 | |
1040 | ret = -EAGAIN; | |
1041 | pmd = *src_pmd; | |
84c3fc4e | 1042 | |
b569a176 PX |
1043 | /* |
1044 | * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA | |
1045 | * does not have the VM_UFFD_WP, which means that the uffd | |
1046 | * fork event is not enabled. | |
1047 | */ | |
1048 | if (!(vma->vm_flags & VM_UFFD_WP)) | |
1049 | pmd = pmd_clear_uffd_wp(pmd); | |
1050 | ||
84c3fc4e ZY |
1051 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1052 | if (unlikely(is_swap_pmd(pmd))) { | |
1053 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1054 | ||
1055 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
1056 | if (is_write_migration_entry(entry)) { | |
1057 | make_migration_entry_read(&entry); | |
1058 | pmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1059 | if (pmd_swp_soft_dirty(*src_pmd)) |
1060 | pmd = pmd_swp_mksoft_dirty(pmd); | |
84c3fc4e ZY |
1061 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1062 | } | |
dd8a67f9 | 1063 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1064 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1065 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
84c3fc4e ZY |
1066 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1067 | ret = 0; | |
1068 | goto out_unlock; | |
1069 | } | |
1070 | #endif | |
1071 | ||
628d47ce | 1072 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1073 | pte_free(dst_mm, pgtable); |
1074 | goto out_unlock; | |
1075 | } | |
fc9fe822 | 1076 | /* |
c4088ebd | 1077 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1078 | * under splitting since we don't split the page itself, only pmd to |
1079 | * a page table. | |
1080 | */ | |
1081 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 1082 | struct page *zero_page; |
97ae1749 KS |
1083 | /* |
1084 | * get_huge_zero_page() will never allocate a new page here, | |
1085 | * since we already have a zero page to copy. It just takes a | |
1086 | * reference. | |
1087 | */ | |
6fcb52a5 | 1088 | zero_page = mm_get_huge_zero_page(dst_mm); |
6b251fc9 | 1089 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 1090 | zero_page); |
fc9fe822 KS |
1091 | ret = 0; |
1092 | goto out_unlock; | |
1093 | } | |
de466bd6 | 1094 | |
628d47ce KS |
1095 | src_page = pmd_page(pmd); |
1096 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e PX |
1097 | |
1098 | /* | |
1099 | * If this page is a potentially pinned page, split and retry the fault | |
1100 | * with smaller page size. Normally this should not happen because the | |
1101 | * userspace should use MADV_DONTFORK upon pinned regions. This is a | |
1102 | * best effort that the pinned pages won't be replaced by another | |
1103 | * random page during the coming copy-on-write. | |
1104 | */ | |
97a7e473 | 1105 | if (unlikely(page_needs_cow_for_dma(vma, src_page))) { |
d042035e PX |
1106 | pte_free(dst_mm, pgtable); |
1107 | spin_unlock(src_ptl); | |
1108 | spin_unlock(dst_ptl); | |
1109 | __split_huge_pmd(vma, src_pmd, addr, false, NULL); | |
1110 | return -EAGAIN; | |
1111 | } | |
1112 | ||
628d47ce KS |
1113 | get_page(src_page); |
1114 | page_dup_rmap(src_page, true); | |
1115 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
c4812909 | 1116 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1117 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 AA |
1118 | |
1119 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
1120 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
1121 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1122 | |
1123 | ret = 0; | |
1124 | out_unlock: | |
c4088ebd KS |
1125 | spin_unlock(src_ptl); |
1126 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1127 | out: |
1128 | return ret; | |
1129 | } | |
1130 | ||
a00cc7d9 MW |
1131 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1132 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1133 | pud_t *pud, int flags) |
a00cc7d9 MW |
1134 | { |
1135 | pud_t _pud; | |
1136 | ||
a8f97366 KS |
1137 | _pud = pud_mkyoung(*pud); |
1138 | if (flags & FOLL_WRITE) | |
1139 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1140 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1141 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1142 | update_mmu_cache_pud(vma, addr, pud); |
1143 | } | |
1144 | ||
1145 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1146 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1147 | { |
1148 | unsigned long pfn = pud_pfn(*pud); | |
1149 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1150 | struct page *page; |
1151 | ||
1152 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1153 | ||
f6f37321 | 1154 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1155 | return NULL; |
1156 | ||
3faa52c0 JH |
1157 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1158 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1159 | (FOLL_PIN | FOLL_GET))) | |
1160 | return NULL; | |
1161 | ||
a00cc7d9 MW |
1162 | if (pud_present(*pud) && pud_devmap(*pud)) |
1163 | /* pass */; | |
1164 | else | |
1165 | return NULL; | |
1166 | ||
1167 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1168 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1169 | |
1170 | /* | |
1171 | * device mapped pages can only be returned if the | |
1172 | * caller will manage the page reference count. | |
3faa52c0 JH |
1173 | * |
1174 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1175 | */ |
3faa52c0 | 1176 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1177 | return ERR_PTR(-EEXIST); |
1178 | ||
1179 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1180 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1181 | if (!*pgmap) | |
a00cc7d9 MW |
1182 | return ERR_PTR(-EFAULT); |
1183 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1184 | if (!try_grab_page(page, flags)) |
1185 | page = ERR_PTR(-ENOMEM); | |
a00cc7d9 MW |
1186 | |
1187 | return page; | |
1188 | } | |
1189 | ||
1190 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1191 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1192 | struct vm_area_struct *vma) | |
1193 | { | |
1194 | spinlock_t *dst_ptl, *src_ptl; | |
1195 | pud_t pud; | |
1196 | int ret; | |
1197 | ||
1198 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1199 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1200 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1201 | ||
1202 | ret = -EAGAIN; | |
1203 | pud = *src_pud; | |
1204 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1205 | goto out_unlock; | |
1206 | ||
1207 | /* | |
1208 | * When page table lock is held, the huge zero pud should not be | |
1209 | * under splitting since we don't split the page itself, only pud to | |
1210 | * a page table. | |
1211 | */ | |
1212 | if (is_huge_zero_pud(pud)) { | |
1213 | /* No huge zero pud yet */ | |
1214 | } | |
1215 | ||
d042035e | 1216 | /* Please refer to comments in copy_huge_pmd() */ |
97a7e473 | 1217 | if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) { |
d042035e PX |
1218 | spin_unlock(src_ptl); |
1219 | spin_unlock(dst_ptl); | |
1220 | __split_huge_pud(vma, src_pud, addr); | |
1221 | return -EAGAIN; | |
1222 | } | |
1223 | ||
a00cc7d9 MW |
1224 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1225 | pud = pud_mkold(pud_wrprotect(pud)); | |
1226 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1227 | ||
1228 | ret = 0; | |
1229 | out_unlock: | |
1230 | spin_unlock(src_ptl); | |
1231 | spin_unlock(dst_ptl); | |
1232 | return ret; | |
1233 | } | |
1234 | ||
1235 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1236 | { | |
1237 | pud_t entry; | |
1238 | unsigned long haddr; | |
1239 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1240 | ||
1241 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1242 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1243 | goto unlock; | |
1244 | ||
1245 | entry = pud_mkyoung(orig_pud); | |
1246 | if (write) | |
1247 | entry = pud_mkdirty(entry); | |
1248 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1249 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1250 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1251 | ||
1252 | unlock: | |
1253 | spin_unlock(vmf->ptl); | |
1254 | } | |
1255 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1256 | ||
82b0f8c3 | 1257 | void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd) |
a1dd450b WD |
1258 | { |
1259 | pmd_t entry; | |
1260 | unsigned long haddr; | |
20f664aa | 1261 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1262 | |
82b0f8c3 JK |
1263 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1264 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1265 | goto unlock; |
1266 | ||
1267 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1268 | if (write) |
1269 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1270 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1271 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1272 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1273 | |
1274 | unlock: | |
82b0f8c3 | 1275 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1276 | } |
1277 | ||
2b740303 | 1278 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) |
71e3aac0 | 1279 | { |
82b0f8c3 | 1280 | struct vm_area_struct *vma = vmf->vma; |
3917c802 | 1281 | struct page *page; |
82b0f8c3 | 1282 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 1283 | |
82b0f8c3 | 1284 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1285 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1286 | |
93b4796d | 1287 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1288 | goto fallback; |
1289 | ||
82b0f8c3 | 1290 | spin_lock(vmf->ptl); |
3917c802 KS |
1291 | |
1292 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1293 | spin_unlock(vmf->ptl); | |
1294 | return 0; | |
1295 | } | |
71e3aac0 AA |
1296 | |
1297 | page = pmd_page(orig_pmd); | |
f6004e73 | 1298 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 KS |
1299 | |
1300 | /* Lock page for reuse_swap_page() */ | |
ba3c4ce6 HY |
1301 | if (!trylock_page(page)) { |
1302 | get_page(page); | |
1303 | spin_unlock(vmf->ptl); | |
1304 | lock_page(page); | |
1305 | spin_lock(vmf->ptl); | |
1306 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1307 | spin_unlock(vmf->ptl); |
ba3c4ce6 HY |
1308 | unlock_page(page); |
1309 | put_page(page); | |
3917c802 | 1310 | return 0; |
ba3c4ce6 HY |
1311 | } |
1312 | put_page(page); | |
1313 | } | |
3917c802 KS |
1314 | |
1315 | /* | |
1316 | * We can only reuse the page if nobody else maps the huge page or it's | |
1317 | * part. | |
1318 | */ | |
ba3c4ce6 | 1319 | if (reuse_swap_page(page, NULL)) { |
71e3aac0 AA |
1320 | pmd_t entry; |
1321 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1322 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1323 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1324 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
ba3c4ce6 | 1325 | unlock_page(page); |
82b0f8c3 | 1326 | spin_unlock(vmf->ptl); |
3917c802 | 1327 | return VM_FAULT_WRITE; |
71e3aac0 | 1328 | } |
3917c802 KS |
1329 | |
1330 | unlock_page(page); | |
82b0f8c3 | 1331 | spin_unlock(vmf->ptl); |
3917c802 KS |
1332 | fallback: |
1333 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1334 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1335 | } |
1336 | ||
8310d48b | 1337 | /* |
a308c71b PX |
1338 | * FOLL_FORCE can write to even unwritable pmd's, but only |
1339 | * after we've gone through a COW cycle and they are dirty. | |
8310d48b KF |
1340 | */ |
1341 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1342 | { | |
a308c71b PX |
1343 | return pmd_write(pmd) || |
1344 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
8310d48b KF |
1345 | } |
1346 | ||
b676b293 | 1347 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1348 | unsigned long addr, |
1349 | pmd_t *pmd, | |
1350 | unsigned int flags) | |
1351 | { | |
b676b293 | 1352 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1353 | struct page *page = NULL; |
1354 | ||
c4088ebd | 1355 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1356 | |
8310d48b | 1357 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1358 | goto out; |
1359 | ||
85facf25 KS |
1360 | /* Avoid dumping huge zero page */ |
1361 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1362 | return ERR_PTR(-EFAULT); | |
1363 | ||
2b4847e7 | 1364 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1365 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1366 | goto out; |
1367 | ||
71e3aac0 | 1368 | page = pmd_page(*pmd); |
ca120cf6 | 1369 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3faa52c0 JH |
1370 | |
1371 | if (!try_grab_page(page, flags)) | |
1372 | return ERR_PTR(-ENOMEM); | |
1373 | ||
3565fce3 | 1374 | if (flags & FOLL_TOUCH) |
a8f97366 | 1375 | touch_pmd(vma, addr, pmd, flags); |
3faa52c0 | 1376 | |
de60f5f1 | 1377 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
e90309c9 KS |
1378 | /* |
1379 | * We don't mlock() pte-mapped THPs. This way we can avoid | |
1380 | * leaking mlocked pages into non-VM_LOCKED VMAs. | |
1381 | * | |
9a73f61b KS |
1382 | * For anon THP: |
1383 | * | |
e90309c9 KS |
1384 | * In most cases the pmd is the only mapping of the page as we |
1385 | * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for | |
1386 | * writable private mappings in populate_vma_page_range(). | |
1387 | * | |
1388 | * The only scenario when we have the page shared here is if we | |
1389 | * mlocking read-only mapping shared over fork(). We skip | |
1390 | * mlocking such pages. | |
9a73f61b KS |
1391 | * |
1392 | * For file THP: | |
1393 | * | |
1394 | * We can expect PageDoubleMap() to be stable under page lock: | |
1395 | * for file pages we set it in page_add_file_rmap(), which | |
1396 | * requires page to be locked. | |
e90309c9 | 1397 | */ |
9a73f61b KS |
1398 | |
1399 | if (PageAnon(page) && compound_mapcount(page) != 1) | |
1400 | goto skip_mlock; | |
1401 | if (PageDoubleMap(page) || !page->mapping) | |
1402 | goto skip_mlock; | |
1403 | if (!trylock_page(page)) | |
1404 | goto skip_mlock; | |
9a73f61b KS |
1405 | if (page->mapping && !PageDoubleMap(page)) |
1406 | mlock_vma_page(page); | |
1407 | unlock_page(page); | |
b676b293 | 1408 | } |
9a73f61b | 1409 | skip_mlock: |
71e3aac0 | 1410 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1411 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 AA |
1412 | |
1413 | out: | |
1414 | return page; | |
1415 | } | |
1416 | ||
d10e63f2 | 1417 | /* NUMA hinting page fault entry point for trans huge pmds */ |
2b740303 | 1418 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) |
d10e63f2 | 1419 | { |
82b0f8c3 | 1420 | struct vm_area_struct *vma = vmf->vma; |
b8916634 | 1421 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1422 | struct page *page; |
82b0f8c3 | 1423 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
98fa15f3 | 1424 | int page_nid = NUMA_NO_NODE, this_nid = numa_node_id(); |
90572890 | 1425 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1426 | bool page_locked; |
1427 | bool migrated = false; | |
b191f9b1 | 1428 | bool was_writable; |
6688cc05 | 1429 | int flags = 0; |
d10e63f2 | 1430 | |
82b0f8c3 JK |
1431 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1432 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) | |
d10e63f2 MG |
1433 | goto out_unlock; |
1434 | ||
de466bd6 MG |
1435 | /* |
1436 | * If there are potential migrations, wait for completion and retry | |
1437 | * without disrupting NUMA hinting information. Do not relock and | |
1438 | * check_same as the page may no longer be mapped. | |
1439 | */ | |
82b0f8c3 JK |
1440 | if (unlikely(pmd_trans_migrating(*vmf->pmd))) { |
1441 | page = pmd_page(*vmf->pmd); | |
3c226c63 MR |
1442 | if (!get_page_unless_zero(page)) |
1443 | goto out_unlock; | |
82b0f8c3 | 1444 | spin_unlock(vmf->ptl); |
48054625 | 1445 | put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE); |
de466bd6 MG |
1446 | goto out; |
1447 | } | |
1448 | ||
d10e63f2 | 1449 | page = pmd_page(pmd); |
a1a46184 | 1450 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1451 | page_nid = page_to_nid(page); |
90572890 | 1452 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1453 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1454 | if (page_nid == this_nid) { |
03c5a6e1 | 1455 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1456 | flags |= TNF_FAULT_LOCAL; |
1457 | } | |
4daae3b4 | 1458 | |
bea66fbd | 1459 | /* See similar comment in do_numa_page for explanation */ |
288bc549 | 1460 | if (!pmd_savedwrite(pmd)) |
6688cc05 PZ |
1461 | flags |= TNF_NO_GROUP; |
1462 | ||
ff9042b1 MG |
1463 | /* |
1464 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1465 | * page_table_lock if at all possible | |
1466 | */ | |
b8916634 MG |
1467 | page_locked = trylock_page(page); |
1468 | target_nid = mpol_misplaced(page, vma, haddr); | |
de466bd6 | 1469 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1470 | if (!page_locked) { |
98fa15f3 | 1471 | page_nid = NUMA_NO_NODE; |
3c226c63 MR |
1472 | if (!get_page_unless_zero(page)) |
1473 | goto out_unlock; | |
82b0f8c3 | 1474 | spin_unlock(vmf->ptl); |
48054625 | 1475 | put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE); |
b8916634 | 1476 | goto out; |
6beb5e8b ML |
1477 | } else if (target_nid == NUMA_NO_NODE) { |
1478 | /* There are no parallel migrations and page is in the right | |
1479 | * node. Clear the numa hinting info in this pmd. | |
1480 | */ | |
1481 | goto clear_pmdnuma; | |
b8916634 MG |
1482 | } |
1483 | ||
2b4847e7 MG |
1484 | /* |
1485 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1486 | * to serialises splits | |
1487 | */ | |
b8916634 | 1488 | get_page(page); |
82b0f8c3 | 1489 | spin_unlock(vmf->ptl); |
b8916634 | 1490 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1491 | |
c69307d5 | 1492 | /* Confirm the PMD did not change while page_table_lock was released */ |
82b0f8c3 JK |
1493 | spin_lock(vmf->ptl); |
1494 | if (unlikely(!pmd_same(pmd, *vmf->pmd))) { | |
b32967ff MG |
1495 | unlock_page(page); |
1496 | put_page(page); | |
98fa15f3 | 1497 | page_nid = NUMA_NO_NODE; |
4daae3b4 | 1498 | goto out_unlock; |
b32967ff | 1499 | } |
ff9042b1 | 1500 | |
c3a489ca MG |
1501 | /* Bail if we fail to protect against THP splits for any reason */ |
1502 | if (unlikely(!anon_vma)) { | |
1503 | put_page(page); | |
98fa15f3 | 1504 | page_nid = NUMA_NO_NODE; |
c3a489ca MG |
1505 | goto clear_pmdnuma; |
1506 | } | |
1507 | ||
8b1b436d PZ |
1508 | /* |
1509 | * Since we took the NUMA fault, we must have observed the !accessible | |
1510 | * bit. Make sure all other CPUs agree with that, to avoid them | |
1511 | * modifying the page we're about to migrate. | |
1512 | * | |
1513 | * Must be done under PTL such that we'll observe the relevant | |
ccde85ba PZ |
1514 | * inc_tlb_flush_pending(). |
1515 | * | |
1516 | * We are not sure a pending tlb flush here is for a huge page | |
1517 | * mapping or not. Hence use the tlb range variant | |
8b1b436d | 1518 | */ |
7066f0f9 | 1519 | if (mm_tlb_flush_pending(vma->vm_mm)) { |
ccde85ba | 1520 | flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); |
7066f0f9 AA |
1521 | /* |
1522 | * change_huge_pmd() released the pmd lock before | |
1523 | * invalidating the secondary MMUs sharing the primary | |
1524 | * MMU pagetables (with ->invalidate_range()). The | |
1525 | * mmu_notifier_invalidate_range_end() (which | |
1526 | * internally calls ->invalidate_range()) in | |
1527 | * change_pmd_range() will run after us, so we can't | |
1528 | * rely on it here and we need an explicit invalidate. | |
1529 | */ | |
1530 | mmu_notifier_invalidate_range(vma->vm_mm, haddr, | |
1531 | haddr + HPAGE_PMD_SIZE); | |
1532 | } | |
8b1b436d | 1533 | |
a54a407f MG |
1534 | /* |
1535 | * Migrate the THP to the requested node, returns with page unlocked | |
8a0516ed | 1536 | * and access rights restored. |
a54a407f | 1537 | */ |
82b0f8c3 | 1538 | spin_unlock(vmf->ptl); |
8b1b436d | 1539 | |
bae473a4 | 1540 | migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma, |
82b0f8c3 | 1541 | vmf->pmd, pmd, vmf->address, page, target_nid); |
6688cc05 PZ |
1542 | if (migrated) { |
1543 | flags |= TNF_MIGRATED; | |
8191acbd | 1544 | page_nid = target_nid; |
074c2381 MG |
1545 | } else |
1546 | flags |= TNF_MIGRATE_FAIL; | |
b32967ff | 1547 | |
8191acbd | 1548 | goto out; |
b32967ff | 1549 | clear_pmdnuma: |
a54a407f | 1550 | BUG_ON(!PageLocked(page)); |
288bc549 | 1551 | was_writable = pmd_savedwrite(pmd); |
4d942466 | 1552 | pmd = pmd_modify(pmd, vma->vm_page_prot); |
b7b04004 | 1553 | pmd = pmd_mkyoung(pmd); |
b191f9b1 MG |
1554 | if (was_writable) |
1555 | pmd = pmd_mkwrite(pmd); | |
82b0f8c3 JK |
1556 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); |
1557 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
a54a407f | 1558 | unlock_page(page); |
d10e63f2 | 1559 | out_unlock: |
82b0f8c3 | 1560 | spin_unlock(vmf->ptl); |
b8916634 MG |
1561 | |
1562 | out: | |
1563 | if (anon_vma) | |
1564 | page_unlock_anon_vma_read(anon_vma); | |
1565 | ||
98fa15f3 | 1566 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1567 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1568 | flags); |
8191acbd | 1569 | |
d10e63f2 MG |
1570 | return 0; |
1571 | } | |
1572 | ||
319904ad HY |
1573 | /* |
1574 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1575 | * Otherwise, return false. | |
1576 | */ | |
1577 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1578 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1579 | { |
1580 | spinlock_t *ptl; | |
1581 | pmd_t orig_pmd; | |
1582 | struct page *page; | |
1583 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1584 | bool ret = false; |
b8d3c4c3 | 1585 | |
ed6a7935 | 1586 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1587 | |
b6ec57f4 KS |
1588 | ptl = pmd_trans_huge_lock(pmd, vma); |
1589 | if (!ptl) | |
25eedabe | 1590 | goto out_unlocked; |
b8d3c4c3 MK |
1591 | |
1592 | orig_pmd = *pmd; | |
319904ad | 1593 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1594 | goto out; |
b8d3c4c3 | 1595 | |
84c3fc4e ZY |
1596 | if (unlikely(!pmd_present(orig_pmd))) { |
1597 | VM_BUG_ON(thp_migration_supported() && | |
1598 | !is_pmd_migration_entry(orig_pmd)); | |
1599 | goto out; | |
1600 | } | |
1601 | ||
b8d3c4c3 MK |
1602 | page = pmd_page(orig_pmd); |
1603 | /* | |
1604 | * If other processes are mapping this page, we couldn't discard | |
1605 | * the page unless they all do MADV_FREE so let's skip the page. | |
1606 | */ | |
1607 | if (page_mapcount(page) != 1) | |
1608 | goto out; | |
1609 | ||
1610 | if (!trylock_page(page)) | |
1611 | goto out; | |
1612 | ||
1613 | /* | |
1614 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1615 | * will deactivate only them. | |
1616 | */ | |
1617 | if (next - addr != HPAGE_PMD_SIZE) { | |
1618 | get_page(page); | |
1619 | spin_unlock(ptl); | |
9818b8cd | 1620 | split_huge_page(page); |
b8d3c4c3 | 1621 | unlock_page(page); |
bbf29ffc | 1622 | put_page(page); |
b8d3c4c3 MK |
1623 | goto out_unlocked; |
1624 | } | |
1625 | ||
1626 | if (PageDirty(page)) | |
1627 | ClearPageDirty(page); | |
1628 | unlock_page(page); | |
1629 | ||
b8d3c4c3 | 1630 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1631 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1632 | orig_pmd = pmd_mkold(orig_pmd); |
1633 | orig_pmd = pmd_mkclean(orig_pmd); | |
1634 | ||
1635 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1636 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1637 | } | |
802a3a92 SL |
1638 | |
1639 | mark_page_lazyfree(page); | |
319904ad | 1640 | ret = true; |
b8d3c4c3 MK |
1641 | out: |
1642 | spin_unlock(ptl); | |
1643 | out_unlocked: | |
1644 | return ret; | |
1645 | } | |
1646 | ||
953c66c2 AK |
1647 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1648 | { | |
1649 | pgtable_t pgtable; | |
1650 | ||
1651 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1652 | pte_free(mm, pgtable); | |
c4812909 | 1653 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1654 | } |
1655 | ||
71e3aac0 | 1656 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1657 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1658 | { |
da146769 | 1659 | pmd_t orig_pmd; |
bf929152 | 1660 | spinlock_t *ptl; |
71e3aac0 | 1661 | |
ed6a7935 | 1662 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1663 | |
b6ec57f4 KS |
1664 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1665 | if (!ptl) | |
da146769 KS |
1666 | return 0; |
1667 | /* | |
1668 | * For architectures like ppc64 we look at deposited pgtable | |
1669 | * when calling pmdp_huge_get_and_clear. So do the | |
1670 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1671 | * operations. | |
1672 | */ | |
93a98695 AK |
1673 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1674 | tlb->fullmm); | |
da146769 | 1675 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1676 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1677 | if (arch_needs_pgtable_deposit()) |
1678 | zap_deposited_table(tlb->mm, pmd); | |
da146769 KS |
1679 | spin_unlock(ptl); |
1680 | if (is_huge_zero_pmd(orig_pmd)) | |
c0f2e176 | 1681 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1682 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1683 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1684 | spin_unlock(ptl); |
c0f2e176 | 1685 | tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); |
da146769 | 1686 | } else { |
616b8371 ZY |
1687 | struct page *page = NULL; |
1688 | int flush_needed = 1; | |
1689 | ||
1690 | if (pmd_present(orig_pmd)) { | |
1691 | page = pmd_page(orig_pmd); | |
1692 | page_remove_rmap(page, true); | |
1693 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); | |
1694 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1695 | } else if (thp_migration_supported()) { | |
1696 | swp_entry_t entry; | |
1697 | ||
1698 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1699 | entry = pmd_to_swp_entry(orig_pmd); | |
a44f89dc | 1700 | page = migration_entry_to_page(entry); |
616b8371 ZY |
1701 | flush_needed = 0; |
1702 | } else | |
1703 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1704 | ||
b5072380 | 1705 | if (PageAnon(page)) { |
c14a6eb4 | 1706 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1707 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1708 | } else { | |
953c66c2 AK |
1709 | if (arch_needs_pgtable_deposit()) |
1710 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1711 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1712 | } |
616b8371 | 1713 | |
da146769 | 1714 | spin_unlock(ptl); |
616b8371 ZY |
1715 | if (flush_needed) |
1716 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1717 | } |
da146769 | 1718 | return 1; |
71e3aac0 AA |
1719 | } |
1720 | ||
1dd38b6c AK |
1721 | #ifndef pmd_move_must_withdraw |
1722 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1723 | spinlock_t *old_pmd_ptl, | |
1724 | struct vm_area_struct *vma) | |
1725 | { | |
1726 | /* | |
1727 | * With split pmd lock we also need to move preallocated | |
1728 | * PTE page table if new_pmd is on different PMD page table. | |
1729 | * | |
1730 | * We also don't deposit and withdraw tables for file pages. | |
1731 | */ | |
1732 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1733 | } | |
1734 | #endif | |
1735 | ||
ab6e3d09 NH |
1736 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1737 | { | |
1738 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1739 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1740 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1741 | else if (pmd_present(pmd)) | |
1742 | pmd = pmd_mksoft_dirty(pmd); | |
1743 | #endif | |
1744 | return pmd; | |
1745 | } | |
1746 | ||
bf8616d5 | 1747 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1748 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1749 | { |
bf929152 | 1750 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1751 | pmd_t pmd; |
37a1c49a | 1752 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1753 | bool force_flush = false; |
37a1c49a | 1754 | |
37a1c49a AA |
1755 | /* |
1756 | * The destination pmd shouldn't be established, free_pgtables() | |
1757 | * should have release it. | |
1758 | */ | |
1759 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1760 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1761 | return false; |
37a1c49a AA |
1762 | } |
1763 | ||
bf929152 KS |
1764 | /* |
1765 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1766 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1767 | */ |
b6ec57f4 KS |
1768 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1769 | if (old_ptl) { | |
bf929152 KS |
1770 | new_ptl = pmd_lockptr(mm, new_pmd); |
1771 | if (new_ptl != old_ptl) | |
1772 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1773 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1774 | if (pmd_present(pmd)) |
a2ce2666 | 1775 | force_flush = true; |
025c5b24 | 1776 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1777 | |
1dd38b6c | 1778 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1779 | pgtable_t pgtable; |
3592806c KS |
1780 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1781 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1782 | } |
ab6e3d09 NH |
1783 | pmd = move_soft_dirty_pmd(pmd); |
1784 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1785 | if (force_flush) |
1786 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1787 | if (new_ptl != old_ptl) |
1788 | spin_unlock(new_ptl); | |
bf929152 | 1789 | spin_unlock(old_ptl); |
4b471e88 | 1790 | return true; |
37a1c49a | 1791 | } |
4b471e88 | 1792 | return false; |
37a1c49a AA |
1793 | } |
1794 | ||
f123d74a MG |
1795 | /* |
1796 | * Returns | |
1797 | * - 0 if PMD could not be locked | |
f0953a1b IM |
1798 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
1799 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary | |
f123d74a | 1800 | */ |
cd7548ab | 1801 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
58705444 | 1802 | unsigned long addr, pgprot_t newprot, unsigned long cp_flags) |
cd7548ab JW |
1803 | { |
1804 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1805 | spinlock_t *ptl; |
0a85e51d KS |
1806 | pmd_t entry; |
1807 | bool preserve_write; | |
1808 | int ret; | |
58705444 | 1809 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1810 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1811 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
cd7548ab | 1812 | |
b6ec57f4 | 1813 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1814 | if (!ptl) |
1815 | return 0; | |
e944fd67 | 1816 | |
0a85e51d KS |
1817 | preserve_write = prot_numa && pmd_write(*pmd); |
1818 | ret = 1; | |
e944fd67 | 1819 | |
84c3fc4e ZY |
1820 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1821 | if (is_swap_pmd(*pmd)) { | |
1822 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1823 | ||
1824 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
1825 | if (is_write_migration_entry(entry)) { | |
1826 | pmd_t newpmd; | |
1827 | /* | |
1828 | * A protection check is difficult so | |
1829 | * just be safe and disable write | |
1830 | */ | |
1831 | make_migration_entry_read(&entry); | |
1832 | newpmd = swp_entry_to_pmd(entry); | |
ab6e3d09 NH |
1833 | if (pmd_swp_soft_dirty(*pmd)) |
1834 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
84c3fc4e ZY |
1835 | set_pmd_at(mm, addr, pmd, newpmd); |
1836 | } | |
1837 | goto unlock; | |
1838 | } | |
1839 | #endif | |
1840 | ||
0a85e51d KS |
1841 | /* |
1842 | * Avoid trapping faults against the zero page. The read-only | |
1843 | * data is likely to be read-cached on the local CPU and | |
1844 | * local/remote hits to the zero page are not interesting. | |
1845 | */ | |
1846 | if (prot_numa && is_huge_zero_pmd(*pmd)) | |
1847 | goto unlock; | |
025c5b24 | 1848 | |
0a85e51d KS |
1849 | if (prot_numa && pmd_protnone(*pmd)) |
1850 | goto unlock; | |
1851 | ||
ced10803 | 1852 | /* |
3e4e28c5 | 1853 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1854 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1855 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1856 | * |
1857 | * CPU0: CPU1: | |
1858 | * change_huge_pmd(prot_numa=1) | |
1859 | * pmdp_huge_get_and_clear_notify() | |
1860 | * madvise_dontneed() | |
1861 | * zap_pmd_range() | |
1862 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1863 | * // skip the pmd | |
1864 | * set_pmd_at(); | |
1865 | * // pmd is re-established | |
1866 | * | |
1867 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1868 | * which may break userspace. | |
1869 | * | |
1870 | * pmdp_invalidate() is required to make sure we don't miss | |
1871 | * dirty/young flags set by hardware. | |
1872 | */ | |
a3cf988f | 1873 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1874 | |
0a85e51d KS |
1875 | entry = pmd_modify(entry, newprot); |
1876 | if (preserve_write) | |
1877 | entry = pmd_mk_savedwrite(entry); | |
292924b2 PX |
1878 | if (uffd_wp) { |
1879 | entry = pmd_wrprotect(entry); | |
1880 | entry = pmd_mkuffd_wp(entry); | |
1881 | } else if (uffd_wp_resolve) { | |
1882 | /* | |
1883 | * Leave the write bit to be handled by PF interrupt | |
1884 | * handler, then things like COW could be properly | |
1885 | * handled. | |
1886 | */ | |
1887 | entry = pmd_clear_uffd_wp(entry); | |
1888 | } | |
0a85e51d KS |
1889 | ret = HPAGE_PMD_NR; |
1890 | set_pmd_at(mm, addr, pmd, entry); | |
1891 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1892 | unlock: | |
1893 | spin_unlock(ptl); | |
025c5b24 NH |
1894 | return ret; |
1895 | } | |
1896 | ||
1897 | /* | |
8f19b0c0 | 1898 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1899 | * |
8f19b0c0 HY |
1900 | * Note that if it returns page table lock pointer, this routine returns without |
1901 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1902 | */ |
b6ec57f4 | 1903 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1904 | { |
b6ec57f4 KS |
1905 | spinlock_t *ptl; |
1906 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1907 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1908 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1909 | return ptl; |
1910 | spin_unlock(ptl); | |
1911 | return NULL; | |
cd7548ab JW |
1912 | } |
1913 | ||
a00cc7d9 MW |
1914 | /* |
1915 | * Returns true if a given pud maps a thp, false otherwise. | |
1916 | * | |
1917 | * Note that if it returns true, this routine returns without unlocking page | |
1918 | * table lock. So callers must unlock it. | |
1919 | */ | |
1920 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1921 | { | |
1922 | spinlock_t *ptl; | |
1923 | ||
1924 | ptl = pud_lock(vma->vm_mm, pud); | |
1925 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1926 | return ptl; | |
1927 | spin_unlock(ptl); | |
1928 | return NULL; | |
1929 | } | |
1930 | ||
1931 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1932 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1933 | pud_t *pud, unsigned long addr) | |
1934 | { | |
a00cc7d9 MW |
1935 | spinlock_t *ptl; |
1936 | ||
1937 | ptl = __pud_trans_huge_lock(pud, vma); | |
1938 | if (!ptl) | |
1939 | return 0; | |
1940 | /* | |
1941 | * For architectures like ppc64 we look at deposited pgtable | |
1942 | * when calling pudp_huge_get_and_clear. So do the | |
1943 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1944 | * operations. | |
1945 | */ | |
70516b93 | 1946 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1947 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1948 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1949 | spin_unlock(ptl); |
1950 | /* No zero page support yet */ | |
1951 | } else { | |
1952 | /* No support for anonymous PUD pages yet */ | |
1953 | BUG(); | |
1954 | } | |
1955 | return 1; | |
1956 | } | |
1957 | ||
1958 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1959 | unsigned long haddr) | |
1960 | { | |
1961 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1962 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1963 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1964 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1965 | ||
ce9311cf | 1966 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1967 | |
1968 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1969 | } | |
1970 | ||
1971 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1972 | unsigned long address) | |
1973 | { | |
1974 | spinlock_t *ptl; | |
ac46d4f3 | 1975 | struct mmu_notifier_range range; |
a00cc7d9 | 1976 | |
7269f999 | 1977 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 1978 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
1979 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
1980 | mmu_notifier_invalidate_range_start(&range); | |
1981 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
1982 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
1983 | goto out; | |
ac46d4f3 | 1984 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
1985 | |
1986 | out: | |
1987 | spin_unlock(ptl); | |
4645b9fe JG |
1988 | /* |
1989 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1990 | * the above pudp_huge_clear_flush_notify() did already call it. | |
1991 | */ | |
ac46d4f3 | 1992 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
1993 | } |
1994 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1995 | ||
eef1b3ba KS |
1996 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1997 | unsigned long haddr, pmd_t *pmd) | |
1998 | { | |
1999 | struct mm_struct *mm = vma->vm_mm; | |
2000 | pgtable_t pgtable; | |
2001 | pmd_t _pmd; | |
2002 | int i; | |
2003 | ||
0f10851e JG |
2004 | /* |
2005 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2006 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2007 | * replacing a zero pmd write protected page with a zero pte write | |
2008 | * protected page. | |
2009 | * | |
ad56b738 | 2010 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
2011 | */ |
2012 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2013 | |
2014 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2015 | pmd_populate(mm, &_pmd, pgtable); | |
2016 | ||
2017 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2018 | pte_t *pte, entry; | |
2019 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2020 | entry = pte_mkspecial(entry); | |
2021 | pte = pte_offset_map(&_pmd, haddr); | |
2022 | VM_BUG_ON(!pte_none(*pte)); | |
2023 | set_pte_at(mm, haddr, pte, entry); | |
2024 | pte_unmap(pte); | |
2025 | } | |
2026 | smp_wmb(); /* make pte visible before pmd */ | |
2027 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2028 | } |
2029 | ||
2030 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2031 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2032 | { |
2033 | struct mm_struct *mm = vma->vm_mm; | |
2034 | struct page *page; | |
2035 | pgtable_t pgtable; | |
423ac9af | 2036 | pmd_t old_pmd, _pmd; |
292924b2 | 2037 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
2ac015e2 | 2038 | unsigned long addr; |
eef1b3ba KS |
2039 | int i; |
2040 | ||
2041 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2042 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2043 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2044 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2045 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2046 | |
2047 | count_vm_event(THP_SPLIT_PMD); | |
2048 | ||
d21b9e57 | 2049 | if (!vma_is_anonymous(vma)) { |
99fa8a48 | 2050 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
2051 | /* |
2052 | * We are going to unmap this huge page. So | |
2053 | * just go ahead and zap it | |
2054 | */ | |
2055 | if (arch_needs_pgtable_deposit()) | |
2056 | zap_deposited_table(mm, pmd); | |
2484ca9b | 2057 | if (vma_is_special_huge(vma)) |
d21b9e57 | 2058 | return; |
99fa8a48 HD |
2059 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
2060 | swp_entry_t entry; | |
2061 | ||
2062 | entry = pmd_to_swp_entry(old_pmd); | |
2063 | page = migration_entry_to_page(entry); | |
2064 | } else { | |
2065 | page = pmd_page(old_pmd); | |
2066 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2067 | set_page_dirty(page); | |
2068 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2069 | SetPageReferenced(page); | |
2070 | page_remove_rmap(page, true); | |
2071 | put_page(page); | |
2072 | } | |
fadae295 | 2073 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2074 | return; |
99fa8a48 HD |
2075 | } |
2076 | ||
3b77e8c8 | 2077 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2078 | /* |
2079 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2080 | * mmu_notifier_invalidate_range() see comments below inside | |
2081 | * __split_huge_pmd() ? | |
2082 | * | |
2083 | * We are going from a zero huge page write protected to zero | |
2084 | * small page also write protected so it does not seems useful | |
2085 | * to invalidate secondary mmu at this time. | |
2086 | */ | |
eef1b3ba KS |
2087 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2088 | } | |
2089 | ||
423ac9af AK |
2090 | /* |
2091 | * Up to this point the pmd is present and huge and userland has the | |
2092 | * whole access to the hugepage during the split (which happens in | |
2093 | * place). If we overwrite the pmd with the not-huge version pointing | |
2094 | * to the pte here (which of course we could if all CPUs were bug | |
2095 | * free), userland could trigger a small page size TLB miss on the | |
2096 | * small sized TLB while the hugepage TLB entry is still established in | |
2097 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2098 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2099 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2100 | * only safe if the permission and cache attributes of the two entries |
2101 | * loaded in the two TLB is identical (which should be the case here). | |
2102 | * But it is generally safer to never allow small and huge TLB entries | |
2103 | * for the same virtual address to be loaded simultaneously. So instead | |
2104 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2105 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2106 | * must remain set at all times on the pmd until the split is complete | |
2107 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2108 | * non-huge version of the pmd entry with pmd_populate. | |
2109 | */ | |
2110 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2111 | ||
423ac9af | 2112 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2113 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2114 | swp_entry_t entry; |
2115 | ||
423ac9af | 2116 | entry = pmd_to_swp_entry(old_pmd); |
a44f89dc | 2117 | page = migration_entry_to_page(entry); |
2e83ee1d PX |
2118 | write = is_write_migration_entry(entry); |
2119 | young = false; | |
2120 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
f45ec5ff | 2121 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2122 | } else { |
423ac9af | 2123 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2124 | if (pmd_dirty(old_pmd)) |
2125 | SetPageDirty(page); | |
2126 | write = pmd_write(old_pmd); | |
2127 | young = pmd_young(old_pmd); | |
2128 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2129 | uffd_wp = pmd_uffd_wp(old_pmd); |
2e83ee1d | 2130 | } |
eef1b3ba | 2131 | VM_BUG_ON_PAGE(!page_count(page), page); |
fe896d18 | 2132 | page_ref_add(page, HPAGE_PMD_NR - 1); |
eef1b3ba | 2133 | |
423ac9af AK |
2134 | /* |
2135 | * Withdraw the table only after we mark the pmd entry invalid. | |
2136 | * This's critical for some architectures (Power). | |
2137 | */ | |
eef1b3ba KS |
2138 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2139 | pmd_populate(mm, &_pmd, pgtable); | |
2140 | ||
2ac015e2 | 2141 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2142 | pte_t entry, *pte; |
2143 | /* | |
2144 | * Note that NUMA hinting access restrictions are not | |
2145 | * transferred to avoid any possibility of altering | |
2146 | * permissions across VMAs. | |
2147 | */ | |
84c3fc4e | 2148 | if (freeze || pmd_migration) { |
ba988280 KS |
2149 | swp_entry_t swp_entry; |
2150 | swp_entry = make_migration_entry(page + i, write); | |
2151 | entry = swp_entry_to_pte(swp_entry); | |
804dd150 AA |
2152 | if (soft_dirty) |
2153 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2154 | if (uffd_wp) |
2155 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2156 | } else { |
6d2329f8 | 2157 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2158 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2159 | if (!write) |
2160 | entry = pte_wrprotect(entry); | |
2161 | if (!young) | |
2162 | entry = pte_mkold(entry); | |
804dd150 AA |
2163 | if (soft_dirty) |
2164 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2165 | if (uffd_wp) |
2166 | entry = pte_mkuffd_wp(entry); | |
ba988280 | 2167 | } |
2ac015e2 | 2168 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2169 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2170 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2171 | if (!pmd_migration) |
eef1b3ba | 2172 | atomic_inc(&page[i]._mapcount); |
ec0abae6 | 2173 | pte_unmap(pte); |
eef1b3ba KS |
2174 | } |
2175 | ||
ec0abae6 RC |
2176 | if (!pmd_migration) { |
2177 | /* | |
2178 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2179 | * false-negative page_mapped(). | |
2180 | */ | |
2181 | if (compound_mapcount(page) > 1 && | |
2182 | !TestSetPageDoubleMap(page)) { | |
eef1b3ba | 2183 | for (i = 0; i < HPAGE_PMD_NR; i++) |
ec0abae6 RC |
2184 | atomic_inc(&page[i]._mapcount); |
2185 | } | |
2186 | ||
2187 | lock_page_memcg(page); | |
2188 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2189 | /* Last compound_mapcount is gone. */ | |
69473e5d MS |
2190 | __mod_lruvec_page_state(page, NR_ANON_THPS, |
2191 | -HPAGE_PMD_NR); | |
ec0abae6 RC |
2192 | if (TestClearPageDoubleMap(page)) { |
2193 | /* No need in mapcount reference anymore */ | |
2194 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2195 | atomic_dec(&page[i]._mapcount); | |
2196 | } | |
eef1b3ba | 2197 | } |
ec0abae6 | 2198 | unlock_page_memcg(page); |
eef1b3ba KS |
2199 | } |
2200 | ||
2201 | smp_wmb(); /* make pte visible before pmd */ | |
2202 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2203 | |
2204 | if (freeze) { | |
2ac015e2 | 2205 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
e9b61f19 KS |
2206 | page_remove_rmap(page + i, false); |
2207 | put_page(page + i); | |
2208 | } | |
2209 | } | |
eef1b3ba KS |
2210 | } |
2211 | ||
2212 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
33f4751e | 2213 | unsigned long address, bool freeze, struct page *page) |
eef1b3ba KS |
2214 | { |
2215 | spinlock_t *ptl; | |
ac46d4f3 | 2216 | struct mmu_notifier_range range; |
1c2f6730 | 2217 | bool do_unlock_page = false; |
c444eb56 | 2218 | pmd_t _pmd; |
eef1b3ba | 2219 | |
7269f999 | 2220 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2221 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2222 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2223 | mmu_notifier_invalidate_range_start(&range); | |
2224 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2225 | |
2226 | /* | |
2227 | * If caller asks to setup a migration entries, we need a page to check | |
2228 | * pmd against. Otherwise we can end up replacing wrong page. | |
2229 | */ | |
2230 | VM_BUG_ON(freeze && !page); | |
c444eb56 AA |
2231 | if (page) { |
2232 | VM_WARN_ON_ONCE(!PageLocked(page)); | |
c444eb56 AA |
2233 | if (page != pmd_page(*pmd)) |
2234 | goto out; | |
2235 | } | |
33f4751e | 2236 | |
c444eb56 | 2237 | repeat: |
5c7fb56e | 2238 | if (pmd_trans_huge(*pmd)) { |
c444eb56 AA |
2239 | if (!page) { |
2240 | page = pmd_page(*pmd); | |
1c2f6730 HD |
2241 | /* |
2242 | * An anonymous page must be locked, to ensure that a | |
2243 | * concurrent reuse_swap_page() sees stable mapcount; | |
2244 | * but reuse_swap_page() is not used on shmem or file, | |
2245 | * and page lock must not be taken when zap_pmd_range() | |
2246 | * calls __split_huge_pmd() while i_mmap_lock is held. | |
2247 | */ | |
2248 | if (PageAnon(page)) { | |
2249 | if (unlikely(!trylock_page(page))) { | |
2250 | get_page(page); | |
2251 | _pmd = *pmd; | |
2252 | spin_unlock(ptl); | |
2253 | lock_page(page); | |
2254 | spin_lock(ptl); | |
2255 | if (unlikely(!pmd_same(*pmd, _pmd))) { | |
2256 | unlock_page(page); | |
2257 | put_page(page); | |
2258 | page = NULL; | |
2259 | goto repeat; | |
2260 | } | |
c444eb56 | 2261 | put_page(page); |
c444eb56 | 2262 | } |
1c2f6730 | 2263 | do_unlock_page = true; |
c444eb56 AA |
2264 | } |
2265 | } | |
5c7fb56e | 2266 | if (PageMlocked(page)) |
5f737714 | 2267 | clear_page_mlock(page); |
84c3fc4e | 2268 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2269 | goto out; |
ac46d4f3 | 2270 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2271 | out: |
eef1b3ba | 2272 | spin_unlock(ptl); |
1c2f6730 | 2273 | if (do_unlock_page) |
c444eb56 | 2274 | unlock_page(page); |
4645b9fe JG |
2275 | /* |
2276 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2277 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2278 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2279 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2280 | * fault will trigger a flush_notify before pointing to a new page | |
2281 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2282 | * page in the meantime) | |
2283 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2284 | * to invalidate secondary tlb entry they are all still valid. | |
2285 | * any further changes to individual pte will notify. So no need | |
2286 | * to call mmu_notifier->invalidate_range() | |
2287 | */ | |
ac46d4f3 | 2288 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2289 | } |
2290 | ||
fec89c10 KS |
2291 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
2292 | bool freeze, struct page *page) | |
94fcc585 | 2293 | { |
f72e7dcd | 2294 | pgd_t *pgd; |
c2febafc | 2295 | p4d_t *p4d; |
f72e7dcd | 2296 | pud_t *pud; |
94fcc585 AA |
2297 | pmd_t *pmd; |
2298 | ||
78ddc534 | 2299 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2300 | if (!pgd_present(*pgd)) |
2301 | return; | |
2302 | ||
c2febafc KS |
2303 | p4d = p4d_offset(pgd, address); |
2304 | if (!p4d_present(*p4d)) | |
2305 | return; | |
2306 | ||
2307 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2308 | if (!pud_present(*pud)) |
2309 | return; | |
2310 | ||
2311 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2312 | |
33f4751e | 2313 | __split_huge_pmd(vma, pmd, address, freeze, page); |
94fcc585 AA |
2314 | } |
2315 | ||
71f9e58e ML |
2316 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2317 | { | |
2318 | /* | |
2319 | * If the new address isn't hpage aligned and it could previously | |
2320 | * contain an hugepage: check if we need to split an huge pmd. | |
2321 | */ | |
2322 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2323 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2324 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2325 | split_huge_pmd_address(vma, address, false, NULL); | |
2326 | } | |
2327 | ||
e1b9996b | 2328 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2329 | unsigned long start, |
2330 | unsigned long end, | |
2331 | long adjust_next) | |
2332 | { | |
71f9e58e ML |
2333 | /* Check if we need to split start first. */ |
2334 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2335 | |
71f9e58e ML |
2336 | /* Check if we need to split end next. */ |
2337 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2338 | |
2339 | /* | |
71f9e58e ML |
2340 | * If we're also updating the vma->vm_next->vm_start, |
2341 | * check if we need to split it. | |
94fcc585 AA |
2342 | */ |
2343 | if (adjust_next > 0) { | |
2344 | struct vm_area_struct *next = vma->vm_next; | |
2345 | unsigned long nstart = next->vm_start; | |
f9d86a60 | 2346 | nstart += adjust_next; |
71f9e58e | 2347 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2348 | } |
2349 | } | |
e9b61f19 | 2350 | |
906f9cdf | 2351 | static void unmap_page(struct page *page) |
e9b61f19 | 2352 | { |
732ed558 | 2353 | enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_SYNC | |
c7ab0d2f | 2354 | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; |
e9b61f19 KS |
2355 | |
2356 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2357 | ||
baa355fd | 2358 | if (PageAnon(page)) |
b5ff8161 | 2359 | ttu_flags |= TTU_SPLIT_FREEZE; |
baa355fd | 2360 | |
504e070d YS |
2361 | try_to_unmap(page, ttu_flags); |
2362 | ||
2363 | VM_WARN_ON_ONCE_PAGE(page_mapped(page), page); | |
e9b61f19 KS |
2364 | } |
2365 | ||
8cce5475 | 2366 | static void remap_page(struct page *page, unsigned int nr) |
e9b61f19 | 2367 | { |
fec89c10 | 2368 | int i; |
ace71a19 KS |
2369 | if (PageTransHuge(page)) { |
2370 | remove_migration_ptes(page, page, true); | |
2371 | } else { | |
8cce5475 | 2372 | for (i = 0; i < nr; i++) |
ace71a19 KS |
2373 | remove_migration_ptes(page + i, page + i, true); |
2374 | } | |
e9b61f19 KS |
2375 | } |
2376 | ||
94866635 | 2377 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2378 | struct lruvec *lruvec, struct list_head *list) |
2379 | { | |
94866635 AS |
2380 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2381 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2382 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2383 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2384 | |
6dbb5741 | 2385 | if (list) { |
88dcb9a3 | 2386 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2387 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2388 | get_page(tail); |
2389 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2390 | } else { |
6dbb5741 AS |
2391 | /* head is still on lru (and we have it frozen) */ |
2392 | VM_WARN_ON(!PageLRU(head)); | |
2393 | SetPageLRU(tail); | |
2394 | list_add_tail(&tail->lru, &head->lru); | |
88dcb9a3 AS |
2395 | } |
2396 | } | |
2397 | ||
8df651c7 | 2398 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2399 | struct lruvec *lruvec, struct list_head *list) |
2400 | { | |
e9b61f19 KS |
2401 | struct page *page_tail = head + tail; |
2402 | ||
8df651c7 | 2403 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2404 | |
2405 | /* | |
605ca5ed KK |
2406 | * Clone page flags before unfreezing refcount. |
2407 | * | |
2408 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2409 | * for example lock_page() which set PG_waiters. |
e9b61f19 | 2410 | */ |
e9b61f19 KS |
2411 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2412 | page_tail->flags |= (head->flags & | |
2413 | ((1L << PG_referenced) | | |
2414 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2415 | (1L << PG_swapcache) | |
e9b61f19 KS |
2416 | (1L << PG_mlocked) | |
2417 | (1L << PG_uptodate) | | |
2418 | (1L << PG_active) | | |
1899ad18 | 2419 | (1L << PG_workingset) | |
e9b61f19 | 2420 | (1L << PG_locked) | |
b8d3c4c3 | 2421 | (1L << PG_unevictable) | |
72e6afa0 CM |
2422 | #ifdef CONFIG_64BIT |
2423 | (1L << PG_arch_2) | | |
2424 | #endif | |
b8d3c4c3 | 2425 | (1L << PG_dirty))); |
e9b61f19 | 2426 | |
173d9d9f HD |
2427 | /* ->mapping in first tail page is compound_mapcount */ |
2428 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2429 | page_tail); | |
2430 | page_tail->mapping = head->mapping; | |
2431 | page_tail->index = head->index + tail; | |
2432 | ||
605ca5ed | 2433 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2434 | smp_wmb(); |
2435 | ||
605ca5ed KK |
2436 | /* |
2437 | * Clear PageTail before unfreezing page refcount. | |
2438 | * | |
2439 | * After successful get_page_unless_zero() might follow put_page() | |
2440 | * which needs correct compound_head(). | |
2441 | */ | |
e9b61f19 KS |
2442 | clear_compound_head(page_tail); |
2443 | ||
605ca5ed KK |
2444 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2445 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2446 | PageSwapCache(head))); | |
2447 | ||
e9b61f19 KS |
2448 | if (page_is_young(head)) |
2449 | set_page_young(page_tail); | |
2450 | if (page_is_idle(head)) | |
2451 | set_page_idle(page_tail); | |
2452 | ||
e9b61f19 | 2453 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2454 | |
2455 | /* | |
2456 | * always add to the tail because some iterators expect new | |
2457 | * pages to show after the currently processed elements - e.g. | |
2458 | * migrate_pages | |
2459 | */ | |
e9b61f19 | 2460 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2461 | } |
2462 | ||
baa355fd | 2463 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2464 | pgoff_t end) |
e9b61f19 KS |
2465 | { |
2466 | struct page *head = compound_head(page); | |
e9b61f19 | 2467 | struct lruvec *lruvec; |
4101196b MWO |
2468 | struct address_space *swap_cache = NULL; |
2469 | unsigned long offset = 0; | |
8cce5475 | 2470 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2471 | int i; |
e9b61f19 | 2472 | |
e9b61f19 | 2473 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2474 | split_page_memcg(head, nr); |
e9b61f19 | 2475 | |
4101196b MWO |
2476 | if (PageAnon(head) && PageSwapCache(head)) { |
2477 | swp_entry_t entry = { .val = page_private(head) }; | |
2478 | ||
2479 | offset = swp_offset(entry); | |
2480 | swap_cache = swap_address_space(entry); | |
2481 | xa_lock(&swap_cache->i_pages); | |
2482 | } | |
2483 | ||
f0953a1b | 2484 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
6168d0da | 2485 | lruvec = lock_page_lruvec(head); |
b6769834 | 2486 | |
8cce5475 | 2487 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2488 | __split_huge_page_tail(head, i, lruvec, list); |
baa355fd KS |
2489 | /* Some pages can be beyond i_size: drop them from page cache */ |
2490 | if (head[i].index >= end) { | |
2d077d4b | 2491 | ClearPageDirty(head + i); |
baa355fd | 2492 | __delete_from_page_cache(head + i, NULL); |
800d8c63 KS |
2493 | if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) |
2494 | shmem_uncharge(head->mapping->host, 1); | |
baa355fd | 2495 | put_page(head + i); |
4101196b MWO |
2496 | } else if (!PageAnon(page)) { |
2497 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2498 | head + i, 0); | |
2499 | } else if (swap_cache) { | |
2500 | __xa_store(&swap_cache->i_pages, offset + i, | |
2501 | head + i, 0); | |
baa355fd KS |
2502 | } |
2503 | } | |
e9b61f19 KS |
2504 | |
2505 | ClearPageCompound(head); | |
6168d0da | 2506 | unlock_page_lruvec(lruvec); |
b6769834 | 2507 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2508 | |
8cce5475 | 2509 | split_page_owner(head, nr); |
f7da677b | 2510 | |
baa355fd KS |
2511 | /* See comment in __split_huge_page_tail() */ |
2512 | if (PageAnon(head)) { | |
aa5dc07f | 2513 | /* Additional pin to swap cache */ |
4101196b | 2514 | if (PageSwapCache(head)) { |
38d8b4e6 | 2515 | page_ref_add(head, 2); |
4101196b MWO |
2516 | xa_unlock(&swap_cache->i_pages); |
2517 | } else { | |
38d8b4e6 | 2518 | page_ref_inc(head); |
4101196b | 2519 | } |
baa355fd | 2520 | } else { |
aa5dc07f | 2521 | /* Additional pin to page cache */ |
baa355fd | 2522 | page_ref_add(head, 2); |
b93b0163 | 2523 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2524 | } |
b6769834 | 2525 | local_irq_enable(); |
e9b61f19 | 2526 | |
8cce5475 | 2527 | remap_page(head, nr); |
e9b61f19 | 2528 | |
c4f9c701 HY |
2529 | if (PageSwapCache(head)) { |
2530 | swp_entry_t entry = { .val = page_private(head) }; | |
2531 | ||
2532 | split_swap_cluster(entry); | |
2533 | } | |
2534 | ||
8cce5475 | 2535 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2536 | struct page *subpage = head + i; |
2537 | if (subpage == page) | |
2538 | continue; | |
2539 | unlock_page(subpage); | |
2540 | ||
2541 | /* | |
2542 | * Subpages may be freed if there wasn't any mapping | |
2543 | * like if add_to_swap() is running on a lru page that | |
2544 | * had its mapping zapped. And freeing these pages | |
2545 | * requires taking the lru_lock so we do the put_page | |
2546 | * of the tail pages after the split is complete. | |
2547 | */ | |
2548 | put_page(subpage); | |
2549 | } | |
2550 | } | |
2551 | ||
b20ce5e0 KS |
2552 | int total_mapcount(struct page *page) |
2553 | { | |
86b562b6 | 2554 | int i, compound, nr, ret; |
b20ce5e0 KS |
2555 | |
2556 | VM_BUG_ON_PAGE(PageTail(page), page); | |
2557 | ||
2558 | if (likely(!PageCompound(page))) | |
2559 | return atomic_read(&page->_mapcount) + 1; | |
2560 | ||
dd78fedd | 2561 | compound = compound_mapcount(page); |
86b562b6 | 2562 | nr = compound_nr(page); |
b20ce5e0 | 2563 | if (PageHuge(page)) |
dd78fedd KS |
2564 | return compound; |
2565 | ret = compound; | |
86b562b6 | 2566 | for (i = 0; i < nr; i++) |
b20ce5e0 | 2567 | ret += atomic_read(&page[i]._mapcount) + 1; |
dd78fedd KS |
2568 | /* File pages has compound_mapcount included in _mapcount */ |
2569 | if (!PageAnon(page)) | |
86b562b6 | 2570 | return ret - compound * nr; |
b20ce5e0 | 2571 | if (PageDoubleMap(page)) |
86b562b6 | 2572 | ret -= nr; |
b20ce5e0 KS |
2573 | return ret; |
2574 | } | |
2575 | ||
6d0a07ed AA |
2576 | /* |
2577 | * This calculates accurately how many mappings a transparent hugepage | |
2578 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2579 | * accuracy is primarily needed to know if copy-on-write faults can | |
2580 | * reuse the page and change the mapping to read-write instead of | |
2581 | * copying them. At the same time this returns the total_mapcount too. | |
2582 | * | |
2583 | * The function returns the highest mapcount any one of the subpages | |
2584 | * has. If the return value is one, even if different processes are | |
2585 | * mapping different subpages of the transparent hugepage, they can | |
2586 | * all reuse it, because each process is reusing a different subpage. | |
2587 | * | |
2588 | * The total_mapcount is instead counting all virtual mappings of the | |
2589 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2590 | * caller all mappings belong to the same "mm" and in turn the | |
2591 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2592 | * local one as no other process may be mapping any of the subpages. | |
2593 | * | |
2594 | * It would be more accurate to replace page_mapcount() with | |
2595 | * page_trans_huge_mapcount(), however we only use | |
2596 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2597 | * need full accuracy to avoid breaking page pinning, because | |
2598 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2599 | */ | |
2600 | int page_trans_huge_mapcount(struct page *page, int *total_mapcount) | |
2601 | { | |
2602 | int i, ret, _total_mapcount, mapcount; | |
2603 | ||
2604 | /* hugetlbfs shouldn't call it */ | |
2605 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2606 | ||
2607 | if (likely(!PageTransCompound(page))) { | |
2608 | mapcount = atomic_read(&page->_mapcount) + 1; | |
2609 | if (total_mapcount) | |
2610 | *total_mapcount = mapcount; | |
2611 | return mapcount; | |
2612 | } | |
2613 | ||
2614 | page = compound_head(page); | |
2615 | ||
2616 | _total_mapcount = ret = 0; | |
65dfe3c3 | 2617 | for (i = 0; i < thp_nr_pages(page); i++) { |
6d0a07ed AA |
2618 | mapcount = atomic_read(&page[i]._mapcount) + 1; |
2619 | ret = max(ret, mapcount); | |
2620 | _total_mapcount += mapcount; | |
2621 | } | |
2622 | if (PageDoubleMap(page)) { | |
2623 | ret -= 1; | |
65dfe3c3 | 2624 | _total_mapcount -= thp_nr_pages(page); |
6d0a07ed AA |
2625 | } |
2626 | mapcount = compound_mapcount(page); | |
2627 | ret += mapcount; | |
2628 | _total_mapcount += mapcount; | |
2629 | if (total_mapcount) | |
2630 | *total_mapcount = _total_mapcount; | |
2631 | return ret; | |
2632 | } | |
2633 | ||
b8f593cd HY |
2634 | /* Racy check whether the huge page can be split */ |
2635 | bool can_split_huge_page(struct page *page, int *pextra_pins) | |
2636 | { | |
2637 | int extra_pins; | |
2638 | ||
aa5dc07f | 2639 | /* Additional pins from page cache */ |
b8f593cd | 2640 | if (PageAnon(page)) |
e2333dad | 2641 | extra_pins = PageSwapCache(page) ? thp_nr_pages(page) : 0; |
b8f593cd | 2642 | else |
e2333dad | 2643 | extra_pins = thp_nr_pages(page); |
b8f593cd HY |
2644 | if (pextra_pins) |
2645 | *pextra_pins = extra_pins; | |
2646 | return total_mapcount(page) == page_count(page) - extra_pins - 1; | |
2647 | } | |
2648 | ||
e9b61f19 KS |
2649 | /* |
2650 | * This function splits huge page into normal pages. @page can point to any | |
2651 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2652 | * | |
2653 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2654 | * The huge page must be locked. | |
2655 | * | |
2656 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2657 | * | |
2658 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2659 | * the hugepage. | |
2660 | * | |
2661 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2662 | * they are not mapped. | |
2663 | * | |
2664 | * Returns 0 if the hugepage is split successfully. | |
2665 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2666 | * us. | |
2667 | */ | |
2668 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2669 | { | |
2670 | struct page *head = compound_head(page); | |
a8803e6c | 2671 | struct deferred_split *ds_queue = get_deferred_split_queue(head); |
baa355fd KS |
2672 | struct anon_vma *anon_vma = NULL; |
2673 | struct address_space *mapping = NULL; | |
504e070d | 2674 | int extra_pins, ret; |
006d3ff2 | 2675 | pgoff_t end; |
e9b61f19 | 2676 | |
cb829624 | 2677 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
a8803e6c WY |
2678 | VM_BUG_ON_PAGE(!PageLocked(head), head); |
2679 | VM_BUG_ON_PAGE(!PageCompound(head), head); | |
e9b61f19 | 2680 | |
a8803e6c | 2681 | if (PageWriteback(head)) |
59807685 HY |
2682 | return -EBUSY; |
2683 | ||
baa355fd KS |
2684 | if (PageAnon(head)) { |
2685 | /* | |
c1e8d7c6 | 2686 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2687 | * prevent the anon_vma disappearing so we first we take a |
2688 | * reference to it and then lock the anon_vma for write. This | |
2689 | * is similar to page_lock_anon_vma_read except the write lock | |
2690 | * is taken to serialise against parallel split or collapse | |
2691 | * operations. | |
2692 | */ | |
2693 | anon_vma = page_get_anon_vma(head); | |
2694 | if (!anon_vma) { | |
2695 | ret = -EBUSY; | |
2696 | goto out; | |
2697 | } | |
006d3ff2 | 2698 | end = -1; |
baa355fd KS |
2699 | mapping = NULL; |
2700 | anon_vma_lock_write(anon_vma); | |
2701 | } else { | |
2702 | mapping = head->mapping; | |
2703 | ||
2704 | /* Truncated ? */ | |
2705 | if (!mapping) { | |
2706 | ret = -EBUSY; | |
2707 | goto out; | |
2708 | } | |
2709 | ||
baa355fd KS |
2710 | anon_vma = NULL; |
2711 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2712 | |
2713 | /* | |
2714 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2715 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2716 | * which cannot be nested inside the page tree lock. So note | |
2717 | * end now: i_size itself may be changed at any moment, but | |
2718 | * head page lock is good enough to serialize the trimming. | |
2719 | */ | |
2720 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
e9b61f19 | 2721 | } |
e9b61f19 KS |
2722 | |
2723 | /* | |
906f9cdf | 2724 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2725 | * split PMDs |
2726 | */ | |
b8f593cd | 2727 | if (!can_split_huge_page(head, &extra_pins)) { |
e9b61f19 KS |
2728 | ret = -EBUSY; |
2729 | goto out_unlock; | |
2730 | } | |
2731 | ||
906f9cdf | 2732 | unmap_page(head); |
e9b61f19 | 2733 | |
b6769834 AS |
2734 | /* block interrupt reentry in xa_lock and spinlock */ |
2735 | local_irq_disable(); | |
baa355fd | 2736 | if (mapping) { |
aa5dc07f | 2737 | XA_STATE(xas, &mapping->i_pages, page_index(head)); |
baa355fd | 2738 | |
baa355fd | 2739 | /* |
aa5dc07f | 2740 | * Check if the head page is present in page cache. |
baa355fd KS |
2741 | * We assume all tail are present too, if head is there. |
2742 | */ | |
aa5dc07f MW |
2743 | xa_lock(&mapping->i_pages); |
2744 | if (xas_load(&xas) != head) | |
baa355fd KS |
2745 | goto fail; |
2746 | } | |
2747 | ||
0139aa7b | 2748 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2749 | spin_lock(&ds_queue->split_queue_lock); |
504e070d | 2750 | if (page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2751 | if (!list_empty(page_deferred_list(head))) { |
364c1eeb | 2752 | ds_queue->split_queue_len--; |
9a982250 KS |
2753 | list_del(page_deferred_list(head)); |
2754 | } | |
afb97172 | 2755 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2756 | if (mapping) { |
bf9ecead MS |
2757 | int nr = thp_nr_pages(head); |
2758 | ||
a8803e6c | 2759 | if (PageSwapBacked(head)) |
57b2847d MS |
2760 | __mod_lruvec_page_state(head, NR_SHMEM_THPS, |
2761 | -nr); | |
06d3eff6 | 2762 | else |
bf9ecead MS |
2763 | __mod_lruvec_page_state(head, NR_FILE_THPS, |
2764 | -nr); | |
06d3eff6 KS |
2765 | } |
2766 | ||
b6769834 | 2767 | __split_huge_page(page, list, end); |
c4f9c701 | 2768 | ret = 0; |
e9b61f19 | 2769 | } else { |
364c1eeb | 2770 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2771 | fail: |
2772 | if (mapping) | |
b93b0163 | 2773 | xa_unlock(&mapping->i_pages); |
b6769834 | 2774 | local_irq_enable(); |
8cce5475 | 2775 | remap_page(head, thp_nr_pages(head)); |
e9b61f19 KS |
2776 | ret = -EBUSY; |
2777 | } | |
2778 | ||
2779 | out_unlock: | |
baa355fd KS |
2780 | if (anon_vma) { |
2781 | anon_vma_unlock_write(anon_vma); | |
2782 | put_anon_vma(anon_vma); | |
2783 | } | |
2784 | if (mapping) | |
2785 | i_mmap_unlock_read(mapping); | |
e9b61f19 KS |
2786 | out: |
2787 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); | |
2788 | return ret; | |
2789 | } | |
9a982250 KS |
2790 | |
2791 | void free_transhuge_page(struct page *page) | |
2792 | { | |
87eaceb3 | 2793 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2794 | unsigned long flags; |
2795 | ||
364c1eeb | 2796 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2797 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2798 | ds_queue->split_queue_len--; |
9a982250 KS |
2799 | list_del(page_deferred_list(page)); |
2800 | } | |
364c1eeb | 2801 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2802 | free_compound_page(page); |
2803 | } | |
2804 | ||
2805 | void deferred_split_huge_page(struct page *page) | |
2806 | { | |
87eaceb3 YS |
2807 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2808 | #ifdef CONFIG_MEMCG | |
bcfe06bf | 2809 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 | 2810 | #endif |
9a982250 KS |
2811 | unsigned long flags; |
2812 | ||
2813 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2814 | ||
87eaceb3 YS |
2815 | /* |
2816 | * The try_to_unmap() in page reclaim path might reach here too, | |
2817 | * this may cause a race condition to corrupt deferred split queue. | |
2818 | * And, if page reclaim is already handling the same page, it is | |
2819 | * unnecessary to handle it again in shrinker. | |
2820 | * | |
2821 | * Check PageSwapCache to determine if the page is being | |
2822 | * handled by page reclaim since THP swap would add the page into | |
2823 | * swap cache before calling try_to_unmap(). | |
2824 | */ | |
2825 | if (PageSwapCache(page)) | |
2826 | return; | |
2827 | ||
364c1eeb | 2828 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2829 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2830 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2831 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2832 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2833 | #ifdef CONFIG_MEMCG |
2834 | if (memcg) | |
2bfd3637 YS |
2835 | set_shrinker_bit(memcg, page_to_nid(page), |
2836 | deferred_split_shrinker.id); | |
87eaceb3 | 2837 | #endif |
9a982250 | 2838 | } |
364c1eeb | 2839 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2840 | } |
2841 | ||
2842 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2843 | struct shrink_control *sc) | |
2844 | { | |
a3d0a918 | 2845 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2846 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2847 | |
2848 | #ifdef CONFIG_MEMCG | |
2849 | if (sc->memcg) | |
2850 | ds_queue = &sc->memcg->deferred_split_queue; | |
2851 | #endif | |
364c1eeb | 2852 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2853 | } |
2854 | ||
2855 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2856 | struct shrink_control *sc) | |
2857 | { | |
a3d0a918 | 2858 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2859 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2860 | unsigned long flags; |
2861 | LIST_HEAD(list), *pos, *next; | |
2862 | struct page *page; | |
2863 | int split = 0; | |
2864 | ||
87eaceb3 YS |
2865 | #ifdef CONFIG_MEMCG |
2866 | if (sc->memcg) | |
2867 | ds_queue = &sc->memcg->deferred_split_queue; | |
2868 | #endif | |
2869 | ||
364c1eeb | 2870 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2871 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2872 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
9a982250 KS |
2873 | page = list_entry((void *)pos, struct page, mapping); |
2874 | page = compound_head(page); | |
e3ae1953 KS |
2875 | if (get_page_unless_zero(page)) { |
2876 | list_move(page_deferred_list(page), &list); | |
2877 | } else { | |
2878 | /* We lost race with put_compound_page() */ | |
9a982250 | 2879 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2880 | ds_queue->split_queue_len--; |
9a982250 | 2881 | } |
e3ae1953 KS |
2882 | if (!--sc->nr_to_scan) |
2883 | break; | |
9a982250 | 2884 | } |
364c1eeb | 2885 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2886 | |
2887 | list_for_each_safe(pos, next, &list) { | |
2888 | page = list_entry((void *)pos, struct page, mapping); | |
fa41b900 KS |
2889 | if (!trylock_page(page)) |
2890 | goto next; | |
9a982250 KS |
2891 | /* split_huge_page() removes page from list on success */ |
2892 | if (!split_huge_page(page)) | |
2893 | split++; | |
2894 | unlock_page(page); | |
fa41b900 | 2895 | next: |
9a982250 KS |
2896 | put_page(page); |
2897 | } | |
2898 | ||
364c1eeb YS |
2899 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2900 | list_splice_tail(&list, &ds_queue->split_queue); | |
2901 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2902 | |
cb8d68ec KS |
2903 | /* |
2904 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2905 | * This can happen if pages were freed under us. | |
2906 | */ | |
364c1eeb | 2907 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2908 | return SHRINK_STOP; |
2909 | return split; | |
9a982250 KS |
2910 | } |
2911 | ||
2912 | static struct shrinker deferred_split_shrinker = { | |
2913 | .count_objects = deferred_split_count, | |
2914 | .scan_objects = deferred_split_scan, | |
2915 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2916 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2917 | SHRINKER_NONSLAB, | |
9a982250 | 2918 | }; |
49071d43 KS |
2919 | |
2920 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2921 | static void split_huge_pages_all(void) |
49071d43 KS |
2922 | { |
2923 | struct zone *zone; | |
2924 | struct page *page; | |
2925 | unsigned long pfn, max_zone_pfn; | |
2926 | unsigned long total = 0, split = 0; | |
2927 | ||
fa6c0231 | 2928 | pr_debug("Split all THPs\n"); |
49071d43 KS |
2929 | for_each_populated_zone(zone) { |
2930 | max_zone_pfn = zone_end_pfn(zone); | |
2931 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2932 | if (!pfn_valid(pfn)) | |
2933 | continue; | |
2934 | ||
2935 | page = pfn_to_page(pfn); | |
2936 | if (!get_page_unless_zero(page)) | |
2937 | continue; | |
2938 | ||
2939 | if (zone != page_zone(page)) | |
2940 | goto next; | |
2941 | ||
baa355fd | 2942 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2943 | goto next; |
2944 | ||
2945 | total++; | |
2946 | lock_page(page); | |
2947 | if (!split_huge_page(page)) | |
2948 | split++; | |
2949 | unlock_page(page); | |
2950 | next: | |
2951 | put_page(page); | |
fa6c0231 | 2952 | cond_resched(); |
49071d43 KS |
2953 | } |
2954 | } | |
2955 | ||
fa6c0231 ZY |
2956 | pr_debug("%lu of %lu THP split\n", split, total); |
2957 | } | |
49071d43 | 2958 | |
fa6c0231 ZY |
2959 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2960 | { | |
2961 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2962 | is_vm_hugetlb_page(vma); | |
2963 | } | |
2964 | ||
2965 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2966 | unsigned long vaddr_end) | |
2967 | { | |
2968 | int ret = 0; | |
2969 | struct task_struct *task; | |
2970 | struct mm_struct *mm; | |
2971 | unsigned long total = 0, split = 0; | |
2972 | unsigned long addr; | |
2973 | ||
2974 | vaddr_start &= PAGE_MASK; | |
2975 | vaddr_end &= PAGE_MASK; | |
2976 | ||
2977 | /* Find the task_struct from pid */ | |
2978 | rcu_read_lock(); | |
2979 | task = find_task_by_vpid(pid); | |
2980 | if (!task) { | |
2981 | rcu_read_unlock(); | |
2982 | ret = -ESRCH; | |
2983 | goto out; | |
2984 | } | |
2985 | get_task_struct(task); | |
2986 | rcu_read_unlock(); | |
2987 | ||
2988 | /* Find the mm_struct */ | |
2989 | mm = get_task_mm(task); | |
2990 | put_task_struct(task); | |
2991 | ||
2992 | if (!mm) { | |
2993 | ret = -EINVAL; | |
2994 | goto out; | |
2995 | } | |
2996 | ||
2997 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
2998 | pid, vaddr_start, vaddr_end); | |
2999 | ||
3000 | mmap_read_lock(mm); | |
3001 | /* | |
3002 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
3003 | * table filled with PTE-mapped THPs, each of which is distinct. | |
3004 | */ | |
3005 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
3006 | struct vm_area_struct *vma = find_vma(mm, addr); | |
3007 | unsigned int follflags; | |
3008 | struct page *page; | |
3009 | ||
3010 | if (!vma || addr < vma->vm_start) | |
3011 | break; | |
3012 | ||
3013 | /* skip special VMA and hugetlb VMA */ | |
3014 | if (vma_not_suitable_for_thp_split(vma)) { | |
3015 | addr = vma->vm_end; | |
3016 | continue; | |
3017 | } | |
3018 | ||
3019 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
3020 | follflags = FOLL_GET | FOLL_DUMP; | |
3021 | page = follow_page(vma, addr, follflags); | |
3022 | ||
3023 | if (IS_ERR(page)) | |
3024 | continue; | |
3025 | if (!page) | |
3026 | continue; | |
3027 | ||
3028 | if (!is_transparent_hugepage(page)) | |
3029 | goto next; | |
3030 | ||
3031 | total++; | |
3032 | if (!can_split_huge_page(compound_head(page), NULL)) | |
3033 | goto next; | |
3034 | ||
3035 | if (!trylock_page(page)) | |
3036 | goto next; | |
3037 | ||
3038 | if (!split_huge_page(page)) | |
3039 | split++; | |
3040 | ||
3041 | unlock_page(page); | |
3042 | next: | |
3043 | put_page(page); | |
3044 | cond_resched(); | |
3045 | } | |
3046 | mmap_read_unlock(mm); | |
3047 | mmput(mm); | |
3048 | ||
3049 | pr_debug("%lu of %lu THP split\n", split, total); | |
3050 | ||
3051 | out: | |
3052 | return ret; | |
49071d43 | 3053 | } |
fa6c0231 | 3054 | |
fbe37501 ZY |
3055 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
3056 | pgoff_t off_end) | |
3057 | { | |
3058 | struct filename *file; | |
3059 | struct file *candidate; | |
3060 | struct address_space *mapping; | |
3061 | int ret = -EINVAL; | |
3062 | pgoff_t index; | |
3063 | int nr_pages = 1; | |
3064 | unsigned long total = 0, split = 0; | |
3065 | ||
3066 | file = getname_kernel(file_path); | |
3067 | if (IS_ERR(file)) | |
3068 | return ret; | |
3069 | ||
3070 | candidate = file_open_name(file, O_RDONLY, 0); | |
3071 | if (IS_ERR(candidate)) | |
3072 | goto out; | |
3073 | ||
3074 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
3075 | file_path, off_start, off_end); | |
3076 | ||
3077 | mapping = candidate->f_mapping; | |
3078 | ||
3079 | for (index = off_start; index < off_end; index += nr_pages) { | |
3080 | struct page *fpage = pagecache_get_page(mapping, index, | |
3081 | FGP_ENTRY | FGP_HEAD, 0); | |
3082 | ||
3083 | nr_pages = 1; | |
3084 | if (xa_is_value(fpage) || !fpage) | |
3085 | continue; | |
3086 | ||
3087 | if (!is_transparent_hugepage(fpage)) | |
3088 | goto next; | |
3089 | ||
3090 | total++; | |
3091 | nr_pages = thp_nr_pages(fpage); | |
3092 | ||
3093 | if (!trylock_page(fpage)) | |
3094 | goto next; | |
3095 | ||
3096 | if (!split_huge_page(fpage)) | |
3097 | split++; | |
3098 | ||
3099 | unlock_page(fpage); | |
3100 | next: | |
3101 | put_page(fpage); | |
3102 | cond_resched(); | |
3103 | } | |
3104 | ||
3105 | filp_close(candidate, NULL); | |
3106 | ret = 0; | |
3107 | ||
3108 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3109 | out: | |
3110 | putname(file); | |
3111 | return ret; | |
3112 | } | |
3113 | ||
fa6c0231 ZY |
3114 | #define MAX_INPUT_BUF_SZ 255 |
3115 | ||
3116 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3117 | size_t count, loff_t *ppops) | |
3118 | { | |
3119 | static DEFINE_MUTEX(split_debug_mutex); | |
3120 | ssize_t ret; | |
fbe37501 ZY |
3121 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3122 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3123 | int pid; |
3124 | unsigned long vaddr_start, vaddr_end; | |
3125 | ||
3126 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3127 | if (ret) | |
3128 | return ret; | |
3129 | ||
3130 | ret = -EFAULT; | |
3131 | ||
3132 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3133 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3134 | goto out; | |
3135 | ||
3136 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3137 | |
3138 | if (input_buf[0] == '/') { | |
3139 | char *tok; | |
3140 | char *buf = input_buf; | |
3141 | char file_path[MAX_INPUT_BUF_SZ]; | |
3142 | pgoff_t off_start = 0, off_end = 0; | |
3143 | size_t input_len = strlen(input_buf); | |
3144 | ||
3145 | tok = strsep(&buf, ","); | |
3146 | if (tok) { | |
3147 | strncpy(file_path, tok, MAX_INPUT_BUF_SZ); | |
3148 | } else { | |
3149 | ret = -EINVAL; | |
3150 | goto out; | |
3151 | } | |
3152 | ||
3153 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3154 | if (ret != 2) { | |
3155 | ret = -EINVAL; | |
3156 | goto out; | |
3157 | } | |
3158 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3159 | if (!ret) | |
3160 | ret = input_len; | |
3161 | ||
3162 | goto out; | |
3163 | } | |
3164 | ||
fa6c0231 ZY |
3165 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3166 | if (ret == 1 && pid == 1) { | |
3167 | split_huge_pages_all(); | |
3168 | ret = strlen(input_buf); | |
3169 | goto out; | |
3170 | } else if (ret != 3) { | |
3171 | ret = -EINVAL; | |
3172 | goto out; | |
3173 | } | |
3174 | ||
3175 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3176 | if (!ret) | |
3177 | ret = strlen(input_buf); | |
3178 | out: | |
3179 | mutex_unlock(&split_debug_mutex); | |
3180 | return ret; | |
3181 | ||
3182 | } | |
3183 | ||
3184 | static const struct file_operations split_huge_pages_fops = { | |
3185 | .owner = THIS_MODULE, | |
3186 | .write = split_huge_pages_write, | |
3187 | .llseek = no_llseek, | |
3188 | }; | |
49071d43 KS |
3189 | |
3190 | static int __init split_huge_pages_debugfs(void) | |
3191 | { | |
d9f7979c GKH |
3192 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3193 | &split_huge_pages_fops); | |
49071d43 KS |
3194 | return 0; |
3195 | } | |
3196 | late_initcall(split_huge_pages_debugfs); | |
3197 | #endif | |
616b8371 ZY |
3198 | |
3199 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
3200 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
3201 | struct page *page) | |
3202 | { | |
3203 | struct vm_area_struct *vma = pvmw->vma; | |
3204 | struct mm_struct *mm = vma->vm_mm; | |
3205 | unsigned long address = pvmw->address; | |
3206 | pmd_t pmdval; | |
3207 | swp_entry_t entry; | |
ab6e3d09 | 3208 | pmd_t pmdswp; |
616b8371 ZY |
3209 | |
3210 | if (!(pvmw->pmd && !pvmw->pte)) | |
3211 | return; | |
3212 | ||
616b8371 | 3213 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3214 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
616b8371 ZY |
3215 | if (pmd_dirty(pmdval)) |
3216 | set_page_dirty(page); | |
3217 | entry = make_migration_entry(page, pmd_write(pmdval)); | |
ab6e3d09 NH |
3218 | pmdswp = swp_entry_to_pmd(entry); |
3219 | if (pmd_soft_dirty(pmdval)) | |
3220 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3221 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
616b8371 ZY |
3222 | page_remove_rmap(page, true); |
3223 | put_page(page); | |
616b8371 ZY |
3224 | } |
3225 | ||
3226 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3227 | { | |
3228 | struct vm_area_struct *vma = pvmw->vma; | |
3229 | struct mm_struct *mm = vma->vm_mm; | |
3230 | unsigned long address = pvmw->address; | |
3231 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
3232 | pmd_t pmde; | |
3233 | swp_entry_t entry; | |
3234 | ||
3235 | if (!(pvmw->pmd && !pvmw->pte)) | |
3236 | return; | |
3237 | ||
3238 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3239 | get_page(new); | |
3240 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
3241 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3242 | pmde = pmd_mksoft_dirty(pmde); | |
616b8371 | 3243 | if (is_write_migration_entry(entry)) |
f55e1014 | 3244 | pmde = maybe_pmd_mkwrite(pmde, vma); |
616b8371 ZY |
3245 | |
3246 | flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); | |
e71769ae NH |
3247 | if (PageAnon(new)) |
3248 | page_add_anon_rmap(new, vma, mmun_start, true); | |
3249 | else | |
3250 | page_add_file_rmap(new, true); | |
616b8371 | 3251 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
e125fe40 | 3252 | if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new)) |
616b8371 ZY |
3253 | mlock_vma_page(new); |
3254 | update_mmu_cache_pmd(vma, address, pvmw->pmd); | |
3255 | } | |
3256 | #endif |