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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> |
a1a3a2fc | 37 | #include <linux/sched/sysctl.h> |
97ae1749 | 38 | |
71e3aac0 AA |
39 | #include <asm/tlb.h> |
40 | #include <asm/pgalloc.h> | |
41 | #include "internal.h" | |
42 | ||
ba76149f | 43 | /* |
b14d595a MD |
44 | * By default, transparent hugepage support is disabled in order to avoid |
45 | * risking an increased memory footprint for applications that are not | |
46 | * guaranteed to benefit from it. When transparent hugepage support is | |
47 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
48 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
49 | * for all hugepage allocations. | |
ba76149f | 50 | */ |
71e3aac0 | 51 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 52 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 53 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
54 | #endif |
55 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
56 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
57 | #endif | |
444eb2a4 | 58 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
59 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
60 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 61 | |
9a982250 | 62 | static struct shrinker deferred_split_shrinker; |
f000565a | 63 | |
97ae1749 | 64 | static atomic_t huge_zero_refcount; |
56873f43 | 65 | struct page *huge_zero_page __read_mostly; |
3b77e8c8 | 66 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 67 | |
e6be37b2 ML |
68 | static inline bool file_thp_enabled(struct vm_area_struct *vma) |
69 | { | |
70 | return transhuge_vma_enabled(vma, vma->vm_flags) && vma->vm_file && | |
71 | !inode_is_open_for_write(vma->vm_file->f_inode) && | |
72 | (vma->vm_flags & VM_EXEC); | |
73 | } | |
74 | ||
75 | bool transparent_hugepage_active(struct vm_area_struct *vma) | |
7635d9cb | 76 | { |
c0630669 YS |
77 | /* The addr is used to check if the vma size fits */ |
78 | unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; | |
79 | ||
80 | if (!transhuge_vma_suitable(vma, addr)) | |
81 | return false; | |
7635d9cb MH |
82 | if (vma_is_anonymous(vma)) |
83 | return __transparent_hugepage_enabled(vma); | |
c0630669 YS |
84 | if (vma_is_shmem(vma)) |
85 | return shmem_huge_enabled(vma); | |
e6be37b2 ML |
86 | if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS)) |
87 | return file_thp_enabled(vma); | |
7635d9cb MH |
88 | |
89 | return false; | |
90 | } | |
91 | ||
aaa9705b | 92 | static bool get_huge_zero_page(void) |
97ae1749 KS |
93 | { |
94 | struct page *zero_page; | |
95 | retry: | |
96 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 97 | return true; |
97ae1749 KS |
98 | |
99 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 100 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
101 | if (!zero_page) { |
102 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 103 | return false; |
d8a8e1f0 KS |
104 | } |
105 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 106 | preempt_disable(); |
5918d10a | 107 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 108 | preempt_enable(); |
5ddacbe9 | 109 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
110 | goto retry; |
111 | } | |
3b77e8c8 | 112 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
113 | |
114 | /* We take additional reference here. It will be put back by shrinker */ | |
115 | atomic_set(&huge_zero_refcount, 2); | |
116 | preempt_enable(); | |
aaa9705b | 117 | return true; |
4a6c1297 KS |
118 | } |
119 | ||
6fcb52a5 | 120 | static void put_huge_zero_page(void) |
4a6c1297 | 121 | { |
97ae1749 KS |
122 | /* |
123 | * Counter should never go to zero here. Only shrinker can put | |
124 | * last reference. | |
125 | */ | |
126 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
127 | } |
128 | ||
6fcb52a5 AL |
129 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
130 | { | |
131 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
132 | return READ_ONCE(huge_zero_page); | |
133 | ||
134 | if (!get_huge_zero_page()) | |
135 | return NULL; | |
136 | ||
137 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
138 | put_huge_zero_page(); | |
139 | ||
140 | return READ_ONCE(huge_zero_page); | |
141 | } | |
142 | ||
143 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
144 | { | |
145 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
146 | put_huge_zero_page(); | |
147 | } | |
148 | ||
48896466 GC |
149 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
150 | struct shrink_control *sc) | |
4a6c1297 | 151 | { |
48896466 GC |
152 | /* we can free zero page only if last reference remains */ |
153 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
154 | } | |
97ae1749 | 155 | |
48896466 GC |
156 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
157 | struct shrink_control *sc) | |
158 | { | |
97ae1749 | 159 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
160 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
161 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 162 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 163 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 164 | return HPAGE_PMD_NR; |
97ae1749 KS |
165 | } |
166 | ||
167 | return 0; | |
4a6c1297 KS |
168 | } |
169 | ||
97ae1749 | 170 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
171 | .count_objects = shrink_huge_zero_page_count, |
172 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
173 | .seeks = DEFAULT_SEEKS, |
174 | }; | |
175 | ||
71e3aac0 | 176 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
177 | static ssize_t enabled_show(struct kobject *kobj, |
178 | struct kobj_attribute *attr, char *buf) | |
179 | { | |
bfb0ffeb JP |
180 | const char *output; |
181 | ||
444eb2a4 | 182 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
183 | output = "[always] madvise never"; |
184 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
185 | &transparent_hugepage_flags)) | |
186 | output = "always [madvise] never"; | |
444eb2a4 | 187 | else |
bfb0ffeb JP |
188 | output = "always madvise [never]"; |
189 | ||
190 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 191 | } |
444eb2a4 | 192 | |
71e3aac0 AA |
193 | static ssize_t enabled_store(struct kobject *kobj, |
194 | struct kobj_attribute *attr, | |
195 | const char *buf, size_t count) | |
196 | { | |
21440d7e | 197 | ssize_t ret = count; |
ba76149f | 198 | |
f42f2552 | 199 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
200 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
201 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 202 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
203 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
204 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 205 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
206 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
207 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
208 | } else | |
209 | ret = -EINVAL; | |
ba76149f AA |
210 | |
211 | if (ret > 0) { | |
b46e756f | 212 | int err = start_stop_khugepaged(); |
ba76149f AA |
213 | if (err) |
214 | ret = err; | |
215 | } | |
ba76149f | 216 | return ret; |
71e3aac0 AA |
217 | } |
218 | static struct kobj_attribute enabled_attr = | |
219 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
220 | ||
b46e756f | 221 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
222 | struct kobj_attribute *attr, char *buf, |
223 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 224 | { |
bfb0ffeb JP |
225 | return sysfs_emit(buf, "%d\n", |
226 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 227 | } |
e27e6151 | 228 | |
b46e756f | 229 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
230 | struct kobj_attribute *attr, |
231 | const char *buf, size_t count, | |
232 | enum transparent_hugepage_flag flag) | |
233 | { | |
e27e6151 BH |
234 | unsigned long value; |
235 | int ret; | |
236 | ||
237 | ret = kstrtoul(buf, 10, &value); | |
238 | if (ret < 0) | |
239 | return ret; | |
240 | if (value > 1) | |
241 | return -EINVAL; | |
242 | ||
243 | if (value) | |
71e3aac0 | 244 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 245 | else |
71e3aac0 | 246 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
247 | |
248 | return count; | |
249 | } | |
250 | ||
71e3aac0 AA |
251 | static ssize_t defrag_show(struct kobject *kobj, |
252 | struct kobj_attribute *attr, char *buf) | |
253 | { | |
bfb0ffeb JP |
254 | const char *output; |
255 | ||
256 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
257 | &transparent_hugepage_flags)) | |
258 | output = "[always] defer defer+madvise madvise never"; | |
259 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
260 | &transparent_hugepage_flags)) | |
261 | output = "always [defer] defer+madvise madvise never"; | |
262 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
263 | &transparent_hugepage_flags)) | |
264 | output = "always defer [defer+madvise] madvise never"; | |
265 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
266 | &transparent_hugepage_flags)) | |
267 | output = "always defer defer+madvise [madvise] never"; | |
268 | else | |
269 | output = "always defer defer+madvise madvise [never]"; | |
270 | ||
271 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 272 | } |
21440d7e | 273 | |
71e3aac0 AA |
274 | static ssize_t defrag_store(struct kobject *kobj, |
275 | struct kobj_attribute *attr, | |
276 | const char *buf, size_t count) | |
277 | { | |
f42f2552 | 278 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
279 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_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_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 283 | } else if (sysfs_streq(buf, "defer+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_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
287 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 288 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
289 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
290 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
291 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
292 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 293 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
294 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
295 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
296 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
297 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 298 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
299 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
300 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
301 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
302 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
303 | } else | |
304 | return -EINVAL; | |
305 | ||
306 | return count; | |
71e3aac0 AA |
307 | } |
308 | static struct kobj_attribute defrag_attr = | |
309 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
310 | ||
79da5407 | 311 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 312 | struct kobj_attribute *attr, char *buf) |
79da5407 | 313 | { |
b46e756f | 314 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 315 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
316 | } |
317 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
318 | struct kobj_attribute *attr, const char *buf, size_t count) | |
319 | { | |
b46e756f | 320 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
321 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
322 | } | |
323 | static struct kobj_attribute use_zero_page_attr = | |
324 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
325 | |
326 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 327 | struct kobj_attribute *attr, char *buf) |
49920d28 | 328 | { |
ae7a927d | 329 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
330 | } |
331 | static struct kobj_attribute hpage_pmd_size_attr = | |
332 | __ATTR_RO(hpage_pmd_size); | |
333 | ||
71e3aac0 AA |
334 | static struct attribute *hugepage_attr[] = { |
335 | &enabled_attr.attr, | |
336 | &defrag_attr.attr, | |
79da5407 | 337 | &use_zero_page_attr.attr, |
49920d28 | 338 | &hpage_pmd_size_attr.attr, |
396bcc52 | 339 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 340 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
341 | #endif |
342 | NULL, | |
343 | }; | |
344 | ||
8aa95a21 | 345 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 346 | .attrs = hugepage_attr, |
ba76149f AA |
347 | }; |
348 | ||
569e5590 | 349 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 350 | { |
71e3aac0 AA |
351 | int err; |
352 | ||
569e5590 SL |
353 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
354 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 355 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 356 | return -ENOMEM; |
ba76149f AA |
357 | } |
358 | ||
569e5590 | 359 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 360 | if (err) { |
ae3a8c1c | 361 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 362 | goto delete_obj; |
ba76149f AA |
363 | } |
364 | ||
569e5590 | 365 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 366 | if (err) { |
ae3a8c1c | 367 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 368 | goto remove_hp_group; |
ba76149f | 369 | } |
569e5590 SL |
370 | |
371 | return 0; | |
372 | ||
373 | remove_hp_group: | |
374 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
375 | delete_obj: | |
376 | kobject_put(*hugepage_kobj); | |
377 | return err; | |
378 | } | |
379 | ||
380 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
381 | { | |
382 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
383 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
384 | kobject_put(hugepage_kobj); | |
385 | } | |
386 | #else | |
387 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
388 | { | |
389 | return 0; | |
390 | } | |
391 | ||
392 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
393 | { | |
394 | } | |
395 | #endif /* CONFIG_SYSFS */ | |
396 | ||
397 | static int __init hugepage_init(void) | |
398 | { | |
399 | int err; | |
400 | struct kobject *hugepage_kobj; | |
401 | ||
402 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
403 | /* |
404 | * Hardware doesn't support hugepages, hence disable | |
405 | * DAX PMD support. | |
406 | */ | |
407 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
408 | return -EINVAL; |
409 | } | |
410 | ||
ff20c2e0 KS |
411 | /* |
412 | * hugepages can't be allocated by the buddy allocator | |
413 | */ | |
414 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
415 | /* | |
416 | * we use page->mapping and page->index in second tail page | |
417 | * as list_head: assuming THP order >= 2 | |
418 | */ | |
419 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
420 | ||
569e5590 SL |
421 | err = hugepage_init_sysfs(&hugepage_kobj); |
422 | if (err) | |
65ebb64f | 423 | goto err_sysfs; |
ba76149f | 424 | |
b46e756f | 425 | err = khugepaged_init(); |
ba76149f | 426 | if (err) |
65ebb64f | 427 | goto err_slab; |
ba76149f | 428 | |
65ebb64f KS |
429 | err = register_shrinker(&huge_zero_page_shrinker); |
430 | if (err) | |
431 | goto err_hzp_shrinker; | |
9a982250 KS |
432 | err = register_shrinker(&deferred_split_shrinker); |
433 | if (err) | |
434 | goto err_split_shrinker; | |
97ae1749 | 435 | |
97562cd2 RR |
436 | /* |
437 | * By default disable transparent hugepages on smaller systems, | |
438 | * where the extra memory used could hurt more than TLB overhead | |
439 | * is likely to save. The admin can still enable it through /sys. | |
440 | */ | |
ca79b0c2 | 441 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 442 | transparent_hugepage_flags = 0; |
79553da2 KS |
443 | return 0; |
444 | } | |
97562cd2 | 445 | |
79553da2 | 446 | err = start_stop_khugepaged(); |
65ebb64f KS |
447 | if (err) |
448 | goto err_khugepaged; | |
ba76149f | 449 | |
569e5590 | 450 | return 0; |
65ebb64f | 451 | err_khugepaged: |
9a982250 KS |
452 | unregister_shrinker(&deferred_split_shrinker); |
453 | err_split_shrinker: | |
65ebb64f KS |
454 | unregister_shrinker(&huge_zero_page_shrinker); |
455 | err_hzp_shrinker: | |
b46e756f | 456 | khugepaged_destroy(); |
65ebb64f | 457 | err_slab: |
569e5590 | 458 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 459 | err_sysfs: |
ba76149f | 460 | return err; |
71e3aac0 | 461 | } |
a64fb3cd | 462 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
463 | |
464 | static int __init setup_transparent_hugepage(char *str) | |
465 | { | |
466 | int ret = 0; | |
467 | if (!str) | |
468 | goto out; | |
469 | if (!strcmp(str, "always")) { | |
470 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
471 | &transparent_hugepage_flags); | |
472 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
473 | &transparent_hugepage_flags); | |
474 | ret = 1; | |
475 | } else if (!strcmp(str, "madvise")) { | |
476 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
477 | &transparent_hugepage_flags); | |
478 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
479 | &transparent_hugepage_flags); | |
480 | ret = 1; | |
481 | } else if (!strcmp(str, "never")) { | |
482 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
483 | &transparent_hugepage_flags); | |
484 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
485 | &transparent_hugepage_flags); | |
486 | ret = 1; | |
487 | } | |
488 | out: | |
489 | if (!ret) | |
ae3a8c1c | 490 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
491 | return ret; |
492 | } | |
493 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
494 | ||
f55e1014 | 495 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 496 | { |
f55e1014 | 497 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
498 | pmd = pmd_mkwrite(pmd); |
499 | return pmd; | |
500 | } | |
501 | ||
87eaceb3 YS |
502 | #ifdef CONFIG_MEMCG |
503 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 504 | { |
bcfe06bf | 505 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 YS |
506 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); |
507 | ||
508 | if (memcg) | |
509 | return &memcg->deferred_split_queue; | |
510 | else | |
511 | return &pgdat->deferred_split_queue; | |
9a982250 | 512 | } |
87eaceb3 YS |
513 | #else |
514 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
515 | { | |
516 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
517 | ||
518 | return &pgdat->deferred_split_queue; | |
519 | } | |
520 | #endif | |
9a982250 KS |
521 | |
522 | void prep_transhuge_page(struct page *page) | |
523 | { | |
524 | /* | |
525 | * we use page->mapping and page->indexlru in second tail page | |
526 | * as list_head: assuming THP order >= 2 | |
527 | */ | |
9a982250 KS |
528 | |
529 | INIT_LIST_HEAD(page_deferred_list(page)); | |
530 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
531 | } | |
532 | ||
005ba37c SC |
533 | bool is_transparent_hugepage(struct page *page) |
534 | { | |
535 | if (!PageCompound(page)) | |
fa1f68cc | 536 | return false; |
005ba37c SC |
537 | |
538 | page = compound_head(page); | |
539 | return is_huge_zero_page(page) || | |
540 | page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; | |
541 | } | |
542 | EXPORT_SYMBOL_GPL(is_transparent_hugepage); | |
543 | ||
97d3d0f9 KS |
544 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
545 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
546 | loff_t off, unsigned long flags, unsigned long size) |
547 | { | |
74d2fad1 TK |
548 | loff_t off_end = off + len; |
549 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 550 | unsigned long len_pad, ret; |
74d2fad1 TK |
551 | |
552 | if (off_end <= off_align || (off_end - off_align) < size) | |
553 | return 0; | |
554 | ||
555 | len_pad = len + size; | |
556 | if (len_pad < len || (off + len_pad) < off) | |
557 | return 0; | |
558 | ||
97d3d0f9 | 559 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 560 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
561 | |
562 | /* | |
563 | * The failure might be due to length padding. The caller will retry | |
564 | * without the padding. | |
565 | */ | |
566 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
567 | return 0; |
568 | ||
97d3d0f9 KS |
569 | /* |
570 | * Do not try to align to THP boundary if allocation at the address | |
571 | * hint succeeds. | |
572 | */ | |
573 | if (ret == addr) | |
574 | return addr; | |
575 | ||
576 | ret += (off - ret) & (size - 1); | |
577 | return ret; | |
74d2fad1 TK |
578 | } |
579 | ||
580 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
581 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
582 | { | |
97d3d0f9 | 583 | unsigned long ret; |
74d2fad1 TK |
584 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
585 | ||
97d3d0f9 KS |
586 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
587 | if (ret) | |
588 | return ret; | |
1854bc6e | 589 | |
74d2fad1 TK |
590 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
591 | } | |
592 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
593 | ||
2b740303 SJ |
594 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
595 | struct page *page, gfp_t gfp) | |
71e3aac0 | 596 | { |
82b0f8c3 | 597 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 598 | pgtable_t pgtable; |
82b0f8c3 | 599 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 600 | vm_fault_t ret = 0; |
71e3aac0 | 601 | |
309381fe | 602 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 603 | |
8f425e4e | 604 | if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { |
6b251fc9 AA |
605 | put_page(page); |
606 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 607 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
608 | return VM_FAULT_FALLBACK; |
609 | } | |
9d82c694 | 610 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 611 | |
4cf58924 | 612 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 613 | if (unlikely(!pgtable)) { |
6b31d595 MH |
614 | ret = VM_FAULT_OOM; |
615 | goto release; | |
00501b53 | 616 | } |
71e3aac0 | 617 | |
c79b57e4 | 618 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
619 | /* |
620 | * The memory barrier inside __SetPageUptodate makes sure that | |
621 | * clear_huge_page writes become visible before the set_pmd_at() | |
622 | * write. | |
623 | */ | |
71e3aac0 AA |
624 | __SetPageUptodate(page); |
625 | ||
82b0f8c3 JK |
626 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
627 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 628 | goto unlock_release; |
71e3aac0 AA |
629 | } else { |
630 | pmd_t entry; | |
6b251fc9 | 631 | |
6b31d595 MH |
632 | ret = check_stable_address_space(vma->vm_mm); |
633 | if (ret) | |
634 | goto unlock_release; | |
635 | ||
6b251fc9 AA |
636 | /* Deliver the page fault to userland */ |
637 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 638 | spin_unlock(vmf->ptl); |
6b251fc9 | 639 | put_page(page); |
bae473a4 | 640 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
641 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
642 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
643 | return ret; | |
6b251fc9 AA |
644 | } |
645 | ||
3122359a | 646 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 647 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
d281ee61 | 648 | page_add_new_anon_rmap(page, vma, haddr, true); |
b518154e | 649 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
650 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
651 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 652 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 653 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 654 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 655 | spin_unlock(vmf->ptl); |
6b251fc9 | 656 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 657 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
658 | } |
659 | ||
aa2e878e | 660 | return 0; |
6b31d595 MH |
661 | unlock_release: |
662 | spin_unlock(vmf->ptl); | |
663 | release: | |
664 | if (pgtable) | |
665 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
666 | put_page(page); |
667 | return ret; | |
668 | ||
71e3aac0 AA |
669 | } |
670 | ||
444eb2a4 | 671 | /* |
21440d7e DR |
672 | * always: directly stall for all thp allocations |
673 | * defer: wake kswapd and fail if not immediately available | |
674 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
675 | * fail if not immediately available | |
676 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
677 | * available | |
678 | * never: never stall for any thp allocation | |
444eb2a4 | 679 | */ |
164cc4fe | 680 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 681 | { |
164cc4fe | 682 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 683 | |
ac79f78d | 684 | /* Always do synchronous compaction */ |
a8282608 AA |
685 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
686 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
687 | |
688 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 689 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 690 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
691 | |
692 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 693 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
694 | return GFP_TRANSHUGE_LIGHT | |
695 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
696 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
697 | |
698 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 699 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
700 | return GFP_TRANSHUGE_LIGHT | |
701 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 702 | |
19deb769 | 703 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
704 | } |
705 | ||
c4088ebd | 706 | /* Caller must hold page table lock. */ |
2efeb8da | 707 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 708 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 709 | struct page *zero_page) |
fc9fe822 KS |
710 | { |
711 | pmd_t entry; | |
7c414164 | 712 | if (!pmd_none(*pmd)) |
2efeb8da | 713 | return; |
5918d10a | 714 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 715 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
716 | if (pgtable) |
717 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 718 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 719 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
720 | } |
721 | ||
2b740303 | 722 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 723 | { |
82b0f8c3 | 724 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 725 | gfp_t gfp; |
71e3aac0 | 726 | struct page *page; |
82b0f8c3 | 727 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 728 | |
43675e6f | 729 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 730 | return VM_FAULT_FALLBACK; |
128ec037 KS |
731 | if (unlikely(anon_vma_prepare(vma))) |
732 | return VM_FAULT_OOM; | |
6d50e60c | 733 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 734 | return VM_FAULT_OOM; |
82b0f8c3 | 735 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 736 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
737 | transparent_hugepage_use_zero_page()) { |
738 | pgtable_t pgtable; | |
739 | struct page *zero_page; | |
2b740303 | 740 | vm_fault_t ret; |
4cf58924 | 741 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 742 | if (unlikely(!pgtable)) |
ba76149f | 743 | return VM_FAULT_OOM; |
6fcb52a5 | 744 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 745 | if (unlikely(!zero_page)) { |
bae473a4 | 746 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 747 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 748 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 749 | } |
82b0f8c3 | 750 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 751 | ret = 0; |
82b0f8c3 | 752 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
753 | ret = check_stable_address_space(vma->vm_mm); |
754 | if (ret) { | |
755 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 756 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 757 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 758 | spin_unlock(vmf->ptl); |
bfe8cc1d | 759 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 760 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
761 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
762 | } else { | |
bae473a4 | 763 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 764 | haddr, vmf->pmd, zero_page); |
fca40573 | 765 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 766 | spin_unlock(vmf->ptl); |
6b251fc9 | 767 | } |
bfe8cc1d | 768 | } else { |
82b0f8c3 | 769 | spin_unlock(vmf->ptl); |
bae473a4 | 770 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 771 | } |
6b251fc9 | 772 | return ret; |
71e3aac0 | 773 | } |
164cc4fe | 774 | gfp = vma_thp_gfp_mask(vma); |
19deb769 | 775 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
776 | if (unlikely(!page)) { |
777 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 778 | return VM_FAULT_FALLBACK; |
128ec037 | 779 | } |
9a982250 | 780 | prep_transhuge_page(page); |
82b0f8c3 | 781 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
782 | } |
783 | ||
ae18d6dc | 784 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
785 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
786 | pgtable_t pgtable) | |
5cad465d MW |
787 | { |
788 | struct mm_struct *mm = vma->vm_mm; | |
789 | pmd_t entry; | |
790 | spinlock_t *ptl; | |
791 | ||
792 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
793 | if (!pmd_none(*pmd)) { |
794 | if (write) { | |
795 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
796 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
797 | goto out_unlock; | |
798 | } | |
799 | entry = pmd_mkyoung(*pmd); | |
800 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
801 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
802 | update_mmu_cache_pmd(vma, addr, pmd); | |
803 | } | |
804 | ||
805 | goto out_unlock; | |
806 | } | |
807 | ||
f25748e3 DW |
808 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
809 | if (pfn_t_devmap(pfn)) | |
810 | entry = pmd_mkdevmap(entry); | |
01871e59 | 811 | if (write) { |
f55e1014 LT |
812 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
813 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 814 | } |
3b6521f5 OH |
815 | |
816 | if (pgtable) { | |
817 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 818 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 819 | pgtable = NULL; |
3b6521f5 OH |
820 | } |
821 | ||
01871e59 RZ |
822 | set_pmd_at(mm, addr, pmd, entry); |
823 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
824 | |
825 | out_unlock: | |
5cad465d | 826 | spin_unlock(ptl); |
c6f3c5ee AK |
827 | if (pgtable) |
828 | pte_free(mm, pgtable); | |
5cad465d MW |
829 | } |
830 | ||
9a9731b1 THV |
831 | /** |
832 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
833 | * @vmf: Structure describing the fault | |
834 | * @pfn: pfn to insert | |
835 | * @pgprot: page protection to use | |
836 | * @write: whether it's a write fault | |
837 | * | |
838 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
839 | * also consult the vmf_insert_mixed_prot() documentation when | |
840 | * @pgprot != @vmf->vma->vm_page_prot. | |
841 | * | |
842 | * Return: vm_fault_t value. | |
843 | */ | |
844 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
845 | pgprot_t pgprot, bool write) | |
5cad465d | 846 | { |
fce86ff5 DW |
847 | unsigned long addr = vmf->address & PMD_MASK; |
848 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 849 | pgtable_t pgtable = NULL; |
fce86ff5 | 850 | |
5cad465d MW |
851 | /* |
852 | * If we had pmd_special, we could avoid all these restrictions, | |
853 | * but we need to be consistent with PTEs and architectures that | |
854 | * can't support a 'special' bit. | |
855 | */ | |
e1fb4a08 DJ |
856 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
857 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
858 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
859 | (VM_PFNMAP|VM_MIXEDMAP)); | |
860 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
861 | |
862 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
863 | return VM_FAULT_SIGBUS; | |
308a047c | 864 | |
3b6521f5 | 865 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 866 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
867 | if (!pgtable) |
868 | return VM_FAULT_OOM; | |
869 | } | |
870 | ||
308a047c BP |
871 | track_pfn_insert(vma, &pgprot, pfn); |
872 | ||
fce86ff5 | 873 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 874 | return VM_FAULT_NOPAGE; |
5cad465d | 875 | } |
9a9731b1 | 876 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 877 | |
a00cc7d9 | 878 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 879 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 880 | { |
f55e1014 | 881 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
882 | pud = pud_mkwrite(pud); |
883 | return pud; | |
884 | } | |
885 | ||
886 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
887 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
888 | { | |
889 | struct mm_struct *mm = vma->vm_mm; | |
890 | pud_t entry; | |
891 | spinlock_t *ptl; | |
892 | ||
893 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
894 | if (!pud_none(*pud)) { |
895 | if (write) { | |
896 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
897 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
898 | goto out_unlock; | |
899 | } | |
900 | entry = pud_mkyoung(*pud); | |
901 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
902 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
903 | update_mmu_cache_pud(vma, addr, pud); | |
904 | } | |
905 | goto out_unlock; | |
906 | } | |
907 | ||
a00cc7d9 MW |
908 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
909 | if (pfn_t_devmap(pfn)) | |
910 | entry = pud_mkdevmap(entry); | |
911 | if (write) { | |
f55e1014 LT |
912 | entry = pud_mkyoung(pud_mkdirty(entry)); |
913 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
914 | } |
915 | set_pud_at(mm, addr, pud, entry); | |
916 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
917 | |
918 | out_unlock: | |
a00cc7d9 MW |
919 | spin_unlock(ptl); |
920 | } | |
921 | ||
9a9731b1 THV |
922 | /** |
923 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
924 | * @vmf: Structure describing the fault | |
925 | * @pfn: pfn to insert | |
926 | * @pgprot: page protection to use | |
927 | * @write: whether it's a write fault | |
928 | * | |
929 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
930 | * also consult the vmf_insert_mixed_prot() documentation when | |
931 | * @pgprot != @vmf->vma->vm_page_prot. | |
932 | * | |
933 | * Return: vm_fault_t value. | |
934 | */ | |
935 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
936 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 937 | { |
fce86ff5 DW |
938 | unsigned long addr = vmf->address & PUD_MASK; |
939 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 940 | |
a00cc7d9 MW |
941 | /* |
942 | * If we had pud_special, we could avoid all these restrictions, | |
943 | * but we need to be consistent with PTEs and architectures that | |
944 | * can't support a 'special' bit. | |
945 | */ | |
62ec0d8c DJ |
946 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
947 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
948 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
949 | (VM_PFNMAP|VM_MIXEDMAP)); | |
950 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
951 | |
952 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
953 | return VM_FAULT_SIGBUS; | |
954 | ||
955 | track_pfn_insert(vma, &pgprot, pfn); | |
956 | ||
fce86ff5 | 957 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
958 | return VM_FAULT_NOPAGE; |
959 | } | |
9a9731b1 | 960 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
961 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
962 | ||
3565fce3 | 963 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 964 | pmd_t *pmd, int flags) |
3565fce3 DW |
965 | { |
966 | pmd_t _pmd; | |
967 | ||
a8f97366 KS |
968 | _pmd = pmd_mkyoung(*pmd); |
969 | if (flags & FOLL_WRITE) | |
970 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 971 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 972 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
973 | update_mmu_cache_pmd(vma, addr, pmd); |
974 | } | |
975 | ||
976 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 977 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
978 | { |
979 | unsigned long pfn = pmd_pfn(*pmd); | |
980 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
981 | struct page *page; |
982 | ||
983 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
984 | ||
8310d48b KF |
985 | /* |
986 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
987 | * not be in this function with `flags & FOLL_COW` set. | |
988 | */ | |
989 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
990 | ||
3faa52c0 JH |
991 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
992 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
993 | (FOLL_PIN | FOLL_GET))) | |
994 | return NULL; | |
995 | ||
f6f37321 | 996 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
997 | return NULL; |
998 | ||
999 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
1000 | /* pass */; | |
1001 | else | |
1002 | return NULL; | |
1003 | ||
1004 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1005 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
1006 | |
1007 | /* | |
1008 | * device mapped pages can only be returned if the | |
1009 | * caller will manage the page reference count. | |
1010 | */ | |
3faa52c0 | 1011 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1012 | return ERR_PTR(-EEXIST); |
1013 | ||
1014 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1015 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1016 | if (!*pgmap) | |
3565fce3 DW |
1017 | return ERR_PTR(-EFAULT); |
1018 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1019 | if (!try_grab_page(page, flags)) |
1020 | page = ERR_PTR(-ENOMEM); | |
3565fce3 DW |
1021 | |
1022 | return page; | |
1023 | } | |
1024 | ||
71e3aac0 AA |
1025 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1026 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
8f34f1ea | 1027 | struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) |
71e3aac0 | 1028 | { |
c4088ebd | 1029 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1030 | struct page *src_page; |
1031 | pmd_t pmd; | |
12c9d70b | 1032 | pgtable_t pgtable = NULL; |
628d47ce | 1033 | int ret = -ENOMEM; |
71e3aac0 | 1034 | |
628d47ce | 1035 | /* Skip if can be re-fill on fault */ |
8f34f1ea | 1036 | if (!vma_is_anonymous(dst_vma)) |
628d47ce KS |
1037 | return 0; |
1038 | ||
4cf58924 | 1039 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1040 | if (unlikely(!pgtable)) |
1041 | goto out; | |
71e3aac0 | 1042 | |
c4088ebd KS |
1043 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1044 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1045 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1046 | |
1047 | ret = -EAGAIN; | |
1048 | pmd = *src_pmd; | |
84c3fc4e ZY |
1049 | |
1050 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1051 | if (unlikely(is_swap_pmd(pmd))) { | |
1052 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1053 | ||
1054 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
4dd845b5 AP |
1055 | if (is_writable_migration_entry(entry)) { |
1056 | entry = make_readable_migration_entry( | |
1057 | swp_offset(entry)); | |
84c3fc4e | 1058 | pmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1059 | if (pmd_swp_soft_dirty(*src_pmd)) |
1060 | pmd = pmd_swp_mksoft_dirty(pmd); | |
8f34f1ea PX |
1061 | if (pmd_swp_uffd_wp(*src_pmd)) |
1062 | pmd = pmd_swp_mkuffd_wp(pmd); | |
84c3fc4e ZY |
1063 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1064 | } | |
dd8a67f9 | 1065 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1066 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1067 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
8f34f1ea PX |
1068 | if (!userfaultfd_wp(dst_vma)) |
1069 | pmd = pmd_swp_clear_uffd_wp(pmd); | |
84c3fc4e ZY |
1070 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1071 | ret = 0; | |
1072 | goto out_unlock; | |
1073 | } | |
1074 | #endif | |
1075 | ||
628d47ce | 1076 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1077 | pte_free(dst_mm, pgtable); |
1078 | goto out_unlock; | |
1079 | } | |
fc9fe822 | 1080 | /* |
c4088ebd | 1081 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1082 | * under splitting since we don't split the page itself, only pmd to |
1083 | * a page table. | |
1084 | */ | |
1085 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 KS |
1086 | /* |
1087 | * get_huge_zero_page() will never allocate a new page here, | |
1088 | * since we already have a zero page to copy. It just takes a | |
1089 | * reference. | |
1090 | */ | |
5fc7a5f6 PX |
1091 | mm_get_huge_zero_page(dst_mm); |
1092 | goto out_zero_page; | |
fc9fe822 | 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 | */ | |
8f34f1ea | 1105 | if (unlikely(page_needs_cow_for_dma(src_vma, src_page))) { |
d042035e PX |
1106 | pte_free(dst_mm, pgtable); |
1107 | spin_unlock(src_ptl); | |
1108 | spin_unlock(dst_ptl); | |
8f34f1ea | 1109 | __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); |
d042035e PX |
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); | |
5fc7a5f6 | 1116 | out_zero_page: |
c4812909 | 1117 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1118 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 1119 | pmdp_set_wrprotect(src_mm, addr, src_pmd); |
8f34f1ea PX |
1120 | if (!userfaultfd_wp(dst_vma)) |
1121 | pmd = pmd_clear_uffd_wp(pmd); | |
71e3aac0 AA |
1122 | pmd = pmd_mkold(pmd_wrprotect(pmd)); |
1123 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1124 | |
1125 | ret = 0; | |
1126 | out_unlock: | |
c4088ebd KS |
1127 | spin_unlock(src_ptl); |
1128 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1129 | out: |
1130 | return ret; | |
1131 | } | |
1132 | ||
a00cc7d9 MW |
1133 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1134 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1135 | pud_t *pud, int flags) |
a00cc7d9 MW |
1136 | { |
1137 | pud_t _pud; | |
1138 | ||
a8f97366 KS |
1139 | _pud = pud_mkyoung(*pud); |
1140 | if (flags & FOLL_WRITE) | |
1141 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1142 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1143 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1144 | update_mmu_cache_pud(vma, addr, pud); |
1145 | } | |
1146 | ||
1147 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1148 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1149 | { |
1150 | unsigned long pfn = pud_pfn(*pud); | |
1151 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1152 | struct page *page; |
1153 | ||
1154 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1155 | ||
f6f37321 | 1156 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1157 | return NULL; |
1158 | ||
3faa52c0 JH |
1159 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1160 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1161 | (FOLL_PIN | FOLL_GET))) | |
1162 | return NULL; | |
1163 | ||
a00cc7d9 MW |
1164 | if (pud_present(*pud) && pud_devmap(*pud)) |
1165 | /* pass */; | |
1166 | else | |
1167 | return NULL; | |
1168 | ||
1169 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1170 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1171 | |
1172 | /* | |
1173 | * device mapped pages can only be returned if the | |
1174 | * caller will manage the page reference count. | |
3faa52c0 JH |
1175 | * |
1176 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1177 | */ |
3faa52c0 | 1178 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1179 | return ERR_PTR(-EEXIST); |
1180 | ||
1181 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1182 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1183 | if (!*pgmap) | |
a00cc7d9 MW |
1184 | return ERR_PTR(-EFAULT); |
1185 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1186 | if (!try_grab_page(page, flags)) |
1187 | page = ERR_PTR(-ENOMEM); | |
a00cc7d9 MW |
1188 | |
1189 | return page; | |
1190 | } | |
1191 | ||
1192 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1193 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1194 | struct vm_area_struct *vma) | |
1195 | { | |
1196 | spinlock_t *dst_ptl, *src_ptl; | |
1197 | pud_t pud; | |
1198 | int ret; | |
1199 | ||
1200 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1201 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1202 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1203 | ||
1204 | ret = -EAGAIN; | |
1205 | pud = *src_pud; | |
1206 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1207 | goto out_unlock; | |
1208 | ||
1209 | /* | |
1210 | * When page table lock is held, the huge zero pud should not be | |
1211 | * under splitting since we don't split the page itself, only pud to | |
1212 | * a page table. | |
1213 | */ | |
1214 | if (is_huge_zero_pud(pud)) { | |
1215 | /* No huge zero pud yet */ | |
1216 | } | |
1217 | ||
d042035e | 1218 | /* Please refer to comments in copy_huge_pmd() */ |
97a7e473 | 1219 | if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) { |
d042035e PX |
1220 | spin_unlock(src_ptl); |
1221 | spin_unlock(dst_ptl); | |
1222 | __split_huge_pud(vma, src_pud, addr); | |
1223 | return -EAGAIN; | |
1224 | } | |
1225 | ||
a00cc7d9 MW |
1226 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1227 | pud = pud_mkold(pud_wrprotect(pud)); | |
1228 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1229 | ||
1230 | ret = 0; | |
1231 | out_unlock: | |
1232 | spin_unlock(src_ptl); | |
1233 | spin_unlock(dst_ptl); | |
1234 | return ret; | |
1235 | } | |
1236 | ||
1237 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1238 | { | |
1239 | pud_t entry; | |
1240 | unsigned long haddr; | |
1241 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1242 | ||
1243 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1244 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1245 | goto unlock; | |
1246 | ||
1247 | entry = pud_mkyoung(orig_pud); | |
1248 | if (write) | |
1249 | entry = pud_mkdirty(entry); | |
1250 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1251 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1252 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1253 | ||
1254 | unlock: | |
1255 | spin_unlock(vmf->ptl); | |
1256 | } | |
1257 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1258 | ||
5db4f15c | 1259 | void huge_pmd_set_accessed(struct vm_fault *vmf) |
a1dd450b WD |
1260 | { |
1261 | pmd_t entry; | |
1262 | unsigned long haddr; | |
20f664aa | 1263 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
5db4f15c | 1264 | pmd_t orig_pmd = vmf->orig_pmd; |
a1dd450b | 1265 | |
82b0f8c3 JK |
1266 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1267 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1268 | goto unlock; |
1269 | ||
1270 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1271 | if (write) |
1272 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1273 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1274 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1275 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1276 | |
1277 | unlock: | |
82b0f8c3 | 1278 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1279 | } |
1280 | ||
5db4f15c | 1281 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) |
71e3aac0 | 1282 | { |
82b0f8c3 | 1283 | struct vm_area_struct *vma = vmf->vma; |
3917c802 | 1284 | struct page *page; |
82b0f8c3 | 1285 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
5db4f15c | 1286 | pmd_t orig_pmd = vmf->orig_pmd; |
71e3aac0 | 1287 | |
82b0f8c3 | 1288 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1289 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1290 | |
93b4796d | 1291 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1292 | goto fallback; |
1293 | ||
82b0f8c3 | 1294 | spin_lock(vmf->ptl); |
3917c802 KS |
1295 | |
1296 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1297 | spin_unlock(vmf->ptl); | |
1298 | return 0; | |
1299 | } | |
71e3aac0 AA |
1300 | |
1301 | page = pmd_page(orig_pmd); | |
f6004e73 | 1302 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 KS |
1303 | |
1304 | /* Lock page for reuse_swap_page() */ | |
ba3c4ce6 HY |
1305 | if (!trylock_page(page)) { |
1306 | get_page(page); | |
1307 | spin_unlock(vmf->ptl); | |
1308 | lock_page(page); | |
1309 | spin_lock(vmf->ptl); | |
1310 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1311 | spin_unlock(vmf->ptl); |
ba3c4ce6 HY |
1312 | unlock_page(page); |
1313 | put_page(page); | |
3917c802 | 1314 | return 0; |
ba3c4ce6 HY |
1315 | } |
1316 | put_page(page); | |
1317 | } | |
3917c802 KS |
1318 | |
1319 | /* | |
1320 | * We can only reuse the page if nobody else maps the huge page or it's | |
1321 | * part. | |
1322 | */ | |
020e8765 | 1323 | if (reuse_swap_page(page)) { |
71e3aac0 AA |
1324 | pmd_t entry; |
1325 | entry = pmd_mkyoung(orig_pmd); | |
f55e1014 | 1326 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1327 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1328 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
ba3c4ce6 | 1329 | unlock_page(page); |
82b0f8c3 | 1330 | spin_unlock(vmf->ptl); |
3917c802 | 1331 | return VM_FAULT_WRITE; |
71e3aac0 | 1332 | } |
3917c802 KS |
1333 | |
1334 | unlock_page(page); | |
82b0f8c3 | 1335 | spin_unlock(vmf->ptl); |
3917c802 KS |
1336 | fallback: |
1337 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1338 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1339 | } |
1340 | ||
8310d48b | 1341 | /* |
a308c71b PX |
1342 | * FOLL_FORCE can write to even unwritable pmd's, but only |
1343 | * after we've gone through a COW cycle and they are dirty. | |
8310d48b KF |
1344 | */ |
1345 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1346 | { | |
a308c71b PX |
1347 | return pmd_write(pmd) || |
1348 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
8310d48b KF |
1349 | } |
1350 | ||
b676b293 | 1351 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1352 | unsigned long addr, |
1353 | pmd_t *pmd, | |
1354 | unsigned int flags) | |
1355 | { | |
b676b293 | 1356 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1357 | struct page *page = NULL; |
1358 | ||
c4088ebd | 1359 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1360 | |
8310d48b | 1361 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1362 | goto out; |
1363 | ||
85facf25 KS |
1364 | /* Avoid dumping huge zero page */ |
1365 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1366 | return ERR_PTR(-EFAULT); | |
1367 | ||
2b4847e7 | 1368 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1369 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1370 | goto out; |
1371 | ||
71e3aac0 | 1372 | page = pmd_page(*pmd); |
ca120cf6 | 1373 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3faa52c0 JH |
1374 | |
1375 | if (!try_grab_page(page, flags)) | |
1376 | return ERR_PTR(-ENOMEM); | |
1377 | ||
3565fce3 | 1378 | if (flags & FOLL_TOUCH) |
a8f97366 | 1379 | touch_pmd(vma, addr, pmd, flags); |
3faa52c0 | 1380 | |
71e3aac0 | 1381 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1382 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 AA |
1383 | |
1384 | out: | |
1385 | return page; | |
1386 | } | |
1387 | ||
d10e63f2 | 1388 | /* NUMA hinting page fault entry point for trans huge pmds */ |
5db4f15c | 1389 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) |
d10e63f2 | 1390 | { |
82b0f8c3 | 1391 | struct vm_area_struct *vma = vmf->vma; |
c5b5a3dd YS |
1392 | pmd_t oldpmd = vmf->orig_pmd; |
1393 | pmd_t pmd; | |
b32967ff | 1394 | struct page *page; |
82b0f8c3 | 1395 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
c5b5a3dd | 1396 | int page_nid = NUMA_NO_NODE; |
90572890 | 1397 | int target_nid, last_cpupid = -1; |
8191acbd | 1398 | bool migrated = false; |
c5b5a3dd | 1399 | bool was_writable = pmd_savedwrite(oldpmd); |
6688cc05 | 1400 | int flags = 0; |
d10e63f2 | 1401 | |
82b0f8c3 | 1402 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
c5b5a3dd | 1403 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { |
82b0f8c3 | 1404 | spin_unlock(vmf->ptl); |
de466bd6 MG |
1405 | goto out; |
1406 | } | |
1407 | ||
c5b5a3dd YS |
1408 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); |
1409 | page = vm_normal_page_pmd(vma, haddr, pmd); | |
1410 | if (!page) | |
1411 | goto out_map; | |
1412 | ||
1413 | /* See similar comment in do_numa_page for explanation */ | |
1414 | if (!was_writable) | |
1415 | flags |= TNF_NO_GROUP; | |
1416 | ||
1417 | page_nid = page_to_nid(page); | |
1418 | last_cpupid = page_cpupid_last(page); | |
1419 | target_nid = numa_migrate_prep(page, vma, haddr, page_nid, | |
1420 | &flags); | |
1421 | ||
1422 | if (target_nid == NUMA_NO_NODE) { | |
1423 | put_page(page); | |
1424 | goto out_map; | |
1425 | } | |
1426 | ||
82b0f8c3 | 1427 | spin_unlock(vmf->ptl); |
8b1b436d | 1428 | |
c5b5a3dd | 1429 | migrated = migrate_misplaced_page(page, vma, target_nid); |
6688cc05 PZ |
1430 | if (migrated) { |
1431 | flags |= TNF_MIGRATED; | |
8191acbd | 1432 | page_nid = target_nid; |
c5b5a3dd | 1433 | } else { |
074c2381 | 1434 | flags |= TNF_MIGRATE_FAIL; |
c5b5a3dd YS |
1435 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1436 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { | |
1437 | spin_unlock(vmf->ptl); | |
1438 | goto out; | |
1439 | } | |
1440 | goto out_map; | |
1441 | } | |
b8916634 MG |
1442 | |
1443 | out: | |
98fa15f3 | 1444 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1445 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1446 | flags); |
8191acbd | 1447 | |
d10e63f2 | 1448 | return 0; |
c5b5a3dd YS |
1449 | |
1450 | out_map: | |
1451 | /* Restore the PMD */ | |
1452 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); | |
1453 | pmd = pmd_mkyoung(pmd); | |
1454 | if (was_writable) | |
1455 | pmd = pmd_mkwrite(pmd); | |
1456 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); | |
1457 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
1458 | spin_unlock(vmf->ptl); | |
1459 | goto out; | |
d10e63f2 MG |
1460 | } |
1461 | ||
319904ad HY |
1462 | /* |
1463 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1464 | * Otherwise, return false. | |
1465 | */ | |
1466 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1467 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1468 | { |
1469 | spinlock_t *ptl; | |
1470 | pmd_t orig_pmd; | |
1471 | struct page *page; | |
1472 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1473 | bool ret = false; |
b8d3c4c3 | 1474 | |
ed6a7935 | 1475 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1476 | |
b6ec57f4 KS |
1477 | ptl = pmd_trans_huge_lock(pmd, vma); |
1478 | if (!ptl) | |
25eedabe | 1479 | goto out_unlocked; |
b8d3c4c3 MK |
1480 | |
1481 | orig_pmd = *pmd; | |
319904ad | 1482 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1483 | goto out; |
b8d3c4c3 | 1484 | |
84c3fc4e ZY |
1485 | if (unlikely(!pmd_present(orig_pmd))) { |
1486 | VM_BUG_ON(thp_migration_supported() && | |
1487 | !is_pmd_migration_entry(orig_pmd)); | |
1488 | goto out; | |
1489 | } | |
1490 | ||
b8d3c4c3 MK |
1491 | page = pmd_page(orig_pmd); |
1492 | /* | |
1493 | * If other processes are mapping this page, we couldn't discard | |
1494 | * the page unless they all do MADV_FREE so let's skip the page. | |
1495 | */ | |
babbbdd0 | 1496 | if (total_mapcount(page) != 1) |
b8d3c4c3 MK |
1497 | goto out; |
1498 | ||
1499 | if (!trylock_page(page)) | |
1500 | goto out; | |
1501 | ||
1502 | /* | |
1503 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1504 | * will deactivate only them. | |
1505 | */ | |
1506 | if (next - addr != HPAGE_PMD_SIZE) { | |
1507 | get_page(page); | |
1508 | spin_unlock(ptl); | |
9818b8cd | 1509 | split_huge_page(page); |
b8d3c4c3 | 1510 | unlock_page(page); |
bbf29ffc | 1511 | put_page(page); |
b8d3c4c3 MK |
1512 | goto out_unlocked; |
1513 | } | |
1514 | ||
1515 | if (PageDirty(page)) | |
1516 | ClearPageDirty(page); | |
1517 | unlock_page(page); | |
1518 | ||
b8d3c4c3 | 1519 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1520 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1521 | orig_pmd = pmd_mkold(orig_pmd); |
1522 | orig_pmd = pmd_mkclean(orig_pmd); | |
1523 | ||
1524 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1525 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1526 | } | |
802a3a92 SL |
1527 | |
1528 | mark_page_lazyfree(page); | |
319904ad | 1529 | ret = true; |
b8d3c4c3 MK |
1530 | out: |
1531 | spin_unlock(ptl); | |
1532 | out_unlocked: | |
1533 | return ret; | |
1534 | } | |
1535 | ||
953c66c2 AK |
1536 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1537 | { | |
1538 | pgtable_t pgtable; | |
1539 | ||
1540 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1541 | pte_free(mm, pgtable); | |
c4812909 | 1542 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1543 | } |
1544 | ||
71e3aac0 | 1545 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1546 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1547 | { |
da146769 | 1548 | pmd_t orig_pmd; |
bf929152 | 1549 | spinlock_t *ptl; |
71e3aac0 | 1550 | |
ed6a7935 | 1551 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1552 | |
b6ec57f4 KS |
1553 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1554 | if (!ptl) | |
da146769 KS |
1555 | return 0; |
1556 | /* | |
1557 | * For architectures like ppc64 we look at deposited pgtable | |
1558 | * when calling pmdp_huge_get_and_clear. So do the | |
1559 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1560 | * operations. | |
1561 | */ | |
93a98695 AK |
1562 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1563 | tlb->fullmm); | |
da146769 | 1564 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1565 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1566 | if (arch_needs_pgtable_deposit()) |
1567 | zap_deposited_table(tlb->mm, pmd); | |
da146769 | 1568 | spin_unlock(ptl); |
da146769 | 1569 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1570 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1571 | spin_unlock(ptl); |
da146769 | 1572 | } else { |
616b8371 ZY |
1573 | struct page *page = NULL; |
1574 | int flush_needed = 1; | |
1575 | ||
1576 | if (pmd_present(orig_pmd)) { | |
1577 | page = pmd_page(orig_pmd); | |
cea86fe2 | 1578 | page_remove_rmap(page, vma, true); |
616b8371 ZY |
1579 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
1580 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1581 | } else if (thp_migration_supported()) { | |
1582 | swp_entry_t entry; | |
1583 | ||
1584 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1585 | entry = pmd_to_swp_entry(orig_pmd); | |
af5cdaf8 | 1586 | page = pfn_swap_entry_to_page(entry); |
616b8371 ZY |
1587 | flush_needed = 0; |
1588 | } else | |
1589 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1590 | ||
b5072380 | 1591 | if (PageAnon(page)) { |
c14a6eb4 | 1592 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1593 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1594 | } else { | |
953c66c2 AK |
1595 | if (arch_needs_pgtable_deposit()) |
1596 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1597 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1598 | } |
616b8371 | 1599 | |
da146769 | 1600 | spin_unlock(ptl); |
616b8371 ZY |
1601 | if (flush_needed) |
1602 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1603 | } |
da146769 | 1604 | return 1; |
71e3aac0 AA |
1605 | } |
1606 | ||
1dd38b6c AK |
1607 | #ifndef pmd_move_must_withdraw |
1608 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1609 | spinlock_t *old_pmd_ptl, | |
1610 | struct vm_area_struct *vma) | |
1611 | { | |
1612 | /* | |
1613 | * With split pmd lock we also need to move preallocated | |
1614 | * PTE page table if new_pmd is on different PMD page table. | |
1615 | * | |
1616 | * We also don't deposit and withdraw tables for file pages. | |
1617 | */ | |
1618 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1619 | } | |
1620 | #endif | |
1621 | ||
ab6e3d09 NH |
1622 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1623 | { | |
1624 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1625 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1626 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1627 | else if (pmd_present(pmd)) | |
1628 | pmd = pmd_mksoft_dirty(pmd); | |
1629 | #endif | |
1630 | return pmd; | |
1631 | } | |
1632 | ||
bf8616d5 | 1633 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1634 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1635 | { |
bf929152 | 1636 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1637 | pmd_t pmd; |
37a1c49a | 1638 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1639 | bool force_flush = false; |
37a1c49a | 1640 | |
37a1c49a AA |
1641 | /* |
1642 | * The destination pmd shouldn't be established, free_pgtables() | |
1643 | * should have release it. | |
1644 | */ | |
1645 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1646 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1647 | return false; |
37a1c49a AA |
1648 | } |
1649 | ||
bf929152 KS |
1650 | /* |
1651 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1652 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1653 | */ |
b6ec57f4 KS |
1654 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1655 | if (old_ptl) { | |
bf929152 KS |
1656 | new_ptl = pmd_lockptr(mm, new_pmd); |
1657 | if (new_ptl != old_ptl) | |
1658 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1659 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1660 | if (pmd_present(pmd)) |
a2ce2666 | 1661 | force_flush = true; |
025c5b24 | 1662 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1663 | |
1dd38b6c | 1664 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1665 | pgtable_t pgtable; |
3592806c KS |
1666 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1667 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1668 | } |
ab6e3d09 NH |
1669 | pmd = move_soft_dirty_pmd(pmd); |
1670 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1671 | if (force_flush) |
1672 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1673 | if (new_ptl != old_ptl) |
1674 | spin_unlock(new_ptl); | |
bf929152 | 1675 | spin_unlock(old_ptl); |
4b471e88 | 1676 | return true; |
37a1c49a | 1677 | } |
4b471e88 | 1678 | return false; |
37a1c49a AA |
1679 | } |
1680 | ||
f123d74a MG |
1681 | /* |
1682 | * Returns | |
1683 | * - 0 if PMD could not be locked | |
f0953a1b | 1684 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
e346e668 | 1685 | * or if prot_numa but THP migration is not supported |
f0953a1b | 1686 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary |
f123d74a | 1687 | */ |
cd7548ab | 1688 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
58705444 | 1689 | unsigned long addr, pgprot_t newprot, unsigned long cp_flags) |
cd7548ab JW |
1690 | { |
1691 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1692 | spinlock_t *ptl; |
0a85e51d KS |
1693 | pmd_t entry; |
1694 | bool preserve_write; | |
1695 | int ret; | |
58705444 | 1696 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1697 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1698 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
cd7548ab | 1699 | |
e346e668 YS |
1700 | if (prot_numa && !thp_migration_supported()) |
1701 | return 1; | |
1702 | ||
b6ec57f4 | 1703 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1704 | if (!ptl) |
1705 | return 0; | |
e944fd67 | 1706 | |
0a85e51d KS |
1707 | preserve_write = prot_numa && pmd_write(*pmd); |
1708 | ret = 1; | |
e944fd67 | 1709 | |
84c3fc4e ZY |
1710 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1711 | if (is_swap_pmd(*pmd)) { | |
1712 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
1713 | ||
1714 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
4dd845b5 | 1715 | if (is_writable_migration_entry(entry)) { |
84c3fc4e ZY |
1716 | pmd_t newpmd; |
1717 | /* | |
1718 | * A protection check is difficult so | |
1719 | * just be safe and disable write | |
1720 | */ | |
4dd845b5 AP |
1721 | entry = make_readable_migration_entry( |
1722 | swp_offset(entry)); | |
84c3fc4e | 1723 | newpmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1724 | if (pmd_swp_soft_dirty(*pmd)) |
1725 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
8f34f1ea PX |
1726 | if (pmd_swp_uffd_wp(*pmd)) |
1727 | newpmd = pmd_swp_mkuffd_wp(newpmd); | |
84c3fc4e ZY |
1728 | set_pmd_at(mm, addr, pmd, newpmd); |
1729 | } | |
1730 | goto unlock; | |
1731 | } | |
1732 | #endif | |
1733 | ||
a1a3a2fc HY |
1734 | if (prot_numa) { |
1735 | struct page *page; | |
1736 | /* | |
1737 | * Avoid trapping faults against the zero page. The read-only | |
1738 | * data is likely to be read-cached on the local CPU and | |
1739 | * local/remote hits to the zero page are not interesting. | |
1740 | */ | |
1741 | if (is_huge_zero_pmd(*pmd)) | |
1742 | goto unlock; | |
025c5b24 | 1743 | |
a1a3a2fc HY |
1744 | if (pmd_protnone(*pmd)) |
1745 | goto unlock; | |
0a85e51d | 1746 | |
a1a3a2fc HY |
1747 | page = pmd_page(*pmd); |
1748 | /* | |
1749 | * Skip scanning top tier node if normal numa | |
1750 | * balancing is disabled | |
1751 | */ | |
1752 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
1753 | node_is_toptier(page_to_nid(page))) | |
1754 | goto unlock; | |
1755 | } | |
ced10803 | 1756 | /* |
3e4e28c5 | 1757 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1758 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1759 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1760 | * |
1761 | * CPU0: CPU1: | |
1762 | * change_huge_pmd(prot_numa=1) | |
1763 | * pmdp_huge_get_and_clear_notify() | |
1764 | * madvise_dontneed() | |
1765 | * zap_pmd_range() | |
1766 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1767 | * // skip the pmd | |
1768 | * set_pmd_at(); | |
1769 | * // pmd is re-established | |
1770 | * | |
1771 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1772 | * which may break userspace. | |
1773 | * | |
1774 | * pmdp_invalidate() is required to make sure we don't miss | |
1775 | * dirty/young flags set by hardware. | |
1776 | */ | |
a3cf988f | 1777 | entry = pmdp_invalidate(vma, addr, pmd); |
ced10803 | 1778 | |
0a85e51d KS |
1779 | entry = pmd_modify(entry, newprot); |
1780 | if (preserve_write) | |
1781 | entry = pmd_mk_savedwrite(entry); | |
292924b2 PX |
1782 | if (uffd_wp) { |
1783 | entry = pmd_wrprotect(entry); | |
1784 | entry = pmd_mkuffd_wp(entry); | |
1785 | } else if (uffd_wp_resolve) { | |
1786 | /* | |
1787 | * Leave the write bit to be handled by PF interrupt | |
1788 | * handler, then things like COW could be properly | |
1789 | * handled. | |
1790 | */ | |
1791 | entry = pmd_clear_uffd_wp(entry); | |
1792 | } | |
0a85e51d KS |
1793 | ret = HPAGE_PMD_NR; |
1794 | set_pmd_at(mm, addr, pmd, entry); | |
1795 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); | |
1796 | unlock: | |
1797 | spin_unlock(ptl); | |
025c5b24 NH |
1798 | return ret; |
1799 | } | |
1800 | ||
1801 | /* | |
8f19b0c0 | 1802 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1803 | * |
8f19b0c0 HY |
1804 | * Note that if it returns page table lock pointer, this routine returns without |
1805 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1806 | */ |
b6ec57f4 | 1807 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1808 | { |
b6ec57f4 KS |
1809 | spinlock_t *ptl; |
1810 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1811 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1812 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1813 | return ptl; |
1814 | spin_unlock(ptl); | |
1815 | return NULL; | |
cd7548ab JW |
1816 | } |
1817 | ||
a00cc7d9 MW |
1818 | /* |
1819 | * Returns true if a given pud maps a thp, false otherwise. | |
1820 | * | |
1821 | * Note that if it returns true, this routine returns without unlocking page | |
1822 | * table lock. So callers must unlock it. | |
1823 | */ | |
1824 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1825 | { | |
1826 | spinlock_t *ptl; | |
1827 | ||
1828 | ptl = pud_lock(vma->vm_mm, pud); | |
1829 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1830 | return ptl; | |
1831 | spin_unlock(ptl); | |
1832 | return NULL; | |
1833 | } | |
1834 | ||
1835 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1836 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1837 | pud_t *pud, unsigned long addr) | |
1838 | { | |
a00cc7d9 MW |
1839 | spinlock_t *ptl; |
1840 | ||
1841 | ptl = __pud_trans_huge_lock(pud, vma); | |
1842 | if (!ptl) | |
1843 | return 0; | |
1844 | /* | |
1845 | * For architectures like ppc64 we look at deposited pgtable | |
1846 | * when calling pudp_huge_get_and_clear. So do the | |
1847 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1848 | * operations. | |
1849 | */ | |
70516b93 | 1850 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1851 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1852 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1853 | spin_unlock(ptl); |
1854 | /* No zero page support yet */ | |
1855 | } else { | |
1856 | /* No support for anonymous PUD pages yet */ | |
1857 | BUG(); | |
1858 | } | |
1859 | return 1; | |
1860 | } | |
1861 | ||
1862 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1863 | unsigned long haddr) | |
1864 | { | |
1865 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1866 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1867 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1868 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1869 | ||
ce9311cf | 1870 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1871 | |
1872 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1873 | } | |
1874 | ||
1875 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1876 | unsigned long address) | |
1877 | { | |
1878 | spinlock_t *ptl; | |
ac46d4f3 | 1879 | struct mmu_notifier_range range; |
a00cc7d9 | 1880 | |
7269f999 | 1881 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 1882 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
1883 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
1884 | mmu_notifier_invalidate_range_start(&range); | |
1885 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
1886 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
1887 | goto out; | |
ac46d4f3 | 1888 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
1889 | |
1890 | out: | |
1891 | spin_unlock(ptl); | |
4645b9fe JG |
1892 | /* |
1893 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1894 | * the above pudp_huge_clear_flush_notify() did already call it. | |
1895 | */ | |
ac46d4f3 | 1896 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
1897 | } |
1898 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1899 | ||
eef1b3ba KS |
1900 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1901 | unsigned long haddr, pmd_t *pmd) | |
1902 | { | |
1903 | struct mm_struct *mm = vma->vm_mm; | |
1904 | pgtable_t pgtable; | |
1905 | pmd_t _pmd; | |
1906 | int i; | |
1907 | ||
0f10851e JG |
1908 | /* |
1909 | * Leave pmd empty until pte is filled note that it is fine to delay | |
1910 | * notification until mmu_notifier_invalidate_range_end() as we are | |
1911 | * replacing a zero pmd write protected page with a zero pte write | |
1912 | * protected page. | |
1913 | * | |
ad56b738 | 1914 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
1915 | */ |
1916 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
1917 | |
1918 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1919 | pmd_populate(mm, &_pmd, pgtable); | |
1920 | ||
1921 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1922 | pte_t *pte, entry; | |
1923 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1924 | entry = pte_mkspecial(entry); | |
1925 | pte = pte_offset_map(&_pmd, haddr); | |
1926 | VM_BUG_ON(!pte_none(*pte)); | |
1927 | set_pte_at(mm, haddr, pte, entry); | |
1928 | pte_unmap(pte); | |
1929 | } | |
1930 | smp_wmb(); /* make pte visible before pmd */ | |
1931 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
1932 | } |
1933 | ||
1934 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 1935 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
1936 | { |
1937 | struct mm_struct *mm = vma->vm_mm; | |
1938 | struct page *page; | |
1939 | pgtable_t pgtable; | |
423ac9af | 1940 | pmd_t old_pmd, _pmd; |
292924b2 | 1941 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
2ac015e2 | 1942 | unsigned long addr; |
eef1b3ba KS |
1943 | int i; |
1944 | ||
1945 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
1946 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1947 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
1948 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
1949 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
1950 | |
1951 | count_vm_event(THP_SPLIT_PMD); | |
1952 | ||
d21b9e57 | 1953 | if (!vma_is_anonymous(vma)) { |
99fa8a48 | 1954 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
1955 | /* |
1956 | * We are going to unmap this huge page. So | |
1957 | * just go ahead and zap it | |
1958 | */ | |
1959 | if (arch_needs_pgtable_deposit()) | |
1960 | zap_deposited_table(mm, pmd); | |
2484ca9b | 1961 | if (vma_is_special_huge(vma)) |
d21b9e57 | 1962 | return; |
99fa8a48 HD |
1963 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
1964 | swp_entry_t entry; | |
1965 | ||
1966 | entry = pmd_to_swp_entry(old_pmd); | |
af5cdaf8 | 1967 | page = pfn_swap_entry_to_page(entry); |
99fa8a48 HD |
1968 | } else { |
1969 | page = pmd_page(old_pmd); | |
1970 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
1971 | set_page_dirty(page); | |
1972 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
1973 | SetPageReferenced(page); | |
cea86fe2 | 1974 | page_remove_rmap(page, vma, true); |
99fa8a48 HD |
1975 | put_page(page); |
1976 | } | |
fadae295 | 1977 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 1978 | return; |
99fa8a48 HD |
1979 | } |
1980 | ||
3b77e8c8 | 1981 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
1982 | /* |
1983 | * FIXME: Do we want to invalidate secondary mmu by calling | |
1984 | * mmu_notifier_invalidate_range() see comments below inside | |
1985 | * __split_huge_pmd() ? | |
1986 | * | |
1987 | * We are going from a zero huge page write protected to zero | |
1988 | * small page also write protected so it does not seems useful | |
1989 | * to invalidate secondary mmu at this time. | |
1990 | */ | |
eef1b3ba KS |
1991 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
1992 | } | |
1993 | ||
423ac9af AK |
1994 | /* |
1995 | * Up to this point the pmd is present and huge and userland has the | |
1996 | * whole access to the hugepage during the split (which happens in | |
1997 | * place). If we overwrite the pmd with the not-huge version pointing | |
1998 | * to the pte here (which of course we could if all CPUs were bug | |
1999 | * free), userland could trigger a small page size TLB miss on the | |
2000 | * small sized TLB while the hugepage TLB entry is still established in | |
2001 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2002 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2003 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2004 | * only safe if the permission and cache attributes of the two entries |
2005 | * loaded in the two TLB is identical (which should be the case here). | |
2006 | * But it is generally safer to never allow small and huge TLB entries | |
2007 | * for the same virtual address to be loaded simultaneously. So instead | |
2008 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2009 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2010 | * must remain set at all times on the pmd until the split is complete | |
2011 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2012 | * non-huge version of the pmd entry with pmd_populate. | |
2013 | */ | |
2014 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2015 | ||
423ac9af | 2016 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2017 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2018 | swp_entry_t entry; |
2019 | ||
423ac9af | 2020 | entry = pmd_to_swp_entry(old_pmd); |
af5cdaf8 | 2021 | page = pfn_swap_entry_to_page(entry); |
4dd845b5 | 2022 | write = is_writable_migration_entry(entry); |
2e83ee1d PX |
2023 | young = false; |
2024 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
f45ec5ff | 2025 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2026 | } else { |
423ac9af | 2027 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2028 | if (pmd_dirty(old_pmd)) |
2029 | SetPageDirty(page); | |
2030 | write = pmd_write(old_pmd); | |
2031 | young = pmd_young(old_pmd); | |
2032 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2033 | uffd_wp = pmd_uffd_wp(old_pmd); |
9d84604b HD |
2034 | VM_BUG_ON_PAGE(!page_count(page), page); |
2035 | page_ref_add(page, HPAGE_PMD_NR - 1); | |
2e83ee1d | 2036 | } |
eef1b3ba | 2037 | |
423ac9af AK |
2038 | /* |
2039 | * Withdraw the table only after we mark the pmd entry invalid. | |
2040 | * This's critical for some architectures (Power). | |
2041 | */ | |
eef1b3ba KS |
2042 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2043 | pmd_populate(mm, &_pmd, pgtable); | |
2044 | ||
2ac015e2 | 2045 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2046 | pte_t entry, *pte; |
2047 | /* | |
2048 | * Note that NUMA hinting access restrictions are not | |
2049 | * transferred to avoid any possibility of altering | |
2050 | * permissions across VMAs. | |
2051 | */ | |
84c3fc4e | 2052 | if (freeze || pmd_migration) { |
ba988280 | 2053 | swp_entry_t swp_entry; |
4dd845b5 AP |
2054 | if (write) |
2055 | swp_entry = make_writable_migration_entry( | |
2056 | page_to_pfn(page + i)); | |
2057 | else | |
2058 | swp_entry = make_readable_migration_entry( | |
2059 | page_to_pfn(page + i)); | |
ba988280 | 2060 | entry = swp_entry_to_pte(swp_entry); |
804dd150 AA |
2061 | if (soft_dirty) |
2062 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2063 | if (uffd_wp) |
2064 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2065 | } else { |
6d2329f8 | 2066 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2067 | entry = maybe_mkwrite(entry, vma); |
ba988280 KS |
2068 | if (!write) |
2069 | entry = pte_wrprotect(entry); | |
2070 | if (!young) | |
2071 | entry = pte_mkold(entry); | |
804dd150 AA |
2072 | if (soft_dirty) |
2073 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2074 | if (uffd_wp) |
2075 | entry = pte_mkuffd_wp(entry); | |
ba988280 | 2076 | } |
2ac015e2 | 2077 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2078 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2079 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2080 | if (!pmd_migration) |
eef1b3ba | 2081 | atomic_inc(&page[i]._mapcount); |
ec0abae6 | 2082 | pte_unmap(pte); |
eef1b3ba KS |
2083 | } |
2084 | ||
ec0abae6 RC |
2085 | if (!pmd_migration) { |
2086 | /* | |
2087 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2088 | * false-negative page_mapped(). | |
2089 | */ | |
2090 | if (compound_mapcount(page) > 1 && | |
2091 | !TestSetPageDoubleMap(page)) { | |
eef1b3ba | 2092 | for (i = 0; i < HPAGE_PMD_NR; i++) |
ec0abae6 RC |
2093 | atomic_inc(&page[i]._mapcount); |
2094 | } | |
2095 | ||
2096 | lock_page_memcg(page); | |
2097 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2098 | /* Last compound_mapcount is gone. */ | |
69473e5d MS |
2099 | __mod_lruvec_page_state(page, NR_ANON_THPS, |
2100 | -HPAGE_PMD_NR); | |
ec0abae6 RC |
2101 | if (TestClearPageDoubleMap(page)) { |
2102 | /* No need in mapcount reference anymore */ | |
2103 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2104 | atomic_dec(&page[i]._mapcount); | |
2105 | } | |
eef1b3ba | 2106 | } |
ec0abae6 | 2107 | unlock_page_memcg(page); |
cea86fe2 HD |
2108 | |
2109 | /* Above is effectively page_remove_rmap(page, vma, true) */ | |
2110 | munlock_vma_page(page, vma, true); | |
eef1b3ba KS |
2111 | } |
2112 | ||
2113 | smp_wmb(); /* make pte visible before pmd */ | |
2114 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2115 | |
2116 | if (freeze) { | |
2ac015e2 | 2117 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
cea86fe2 | 2118 | page_remove_rmap(page + i, vma, false); |
e9b61f19 KS |
2119 | put_page(page + i); |
2120 | } | |
2121 | } | |
eef1b3ba KS |
2122 | } |
2123 | ||
2124 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
af28a988 | 2125 | unsigned long address, bool freeze, struct folio *folio) |
eef1b3ba KS |
2126 | { |
2127 | spinlock_t *ptl; | |
ac46d4f3 | 2128 | struct mmu_notifier_range range; |
af28a988 | 2129 | bool do_unlock_folio = false; |
c444eb56 | 2130 | pmd_t _pmd; |
eef1b3ba | 2131 | |
7269f999 | 2132 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2133 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2134 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2135 | mmu_notifier_invalidate_range_start(&range); | |
2136 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2137 | |
2138 | /* | |
af28a988 MWO |
2139 | * If caller asks to setup a migration entry, we need a folio to check |
2140 | * pmd against. Otherwise we can end up replacing wrong folio. | |
33f4751e | 2141 | */ |
af28a988 MWO |
2142 | VM_BUG_ON(freeze && !folio); |
2143 | if (folio) { | |
2144 | VM_WARN_ON_ONCE(!folio_test_locked(folio)); | |
2145 | if (folio != page_folio(pmd_page(*pmd))) | |
c444eb56 AA |
2146 | goto out; |
2147 | } | |
33f4751e | 2148 | |
c444eb56 | 2149 | repeat: |
5c7fb56e | 2150 | if (pmd_trans_huge(*pmd)) { |
af28a988 MWO |
2151 | if (!folio) { |
2152 | folio = page_folio(pmd_page(*pmd)); | |
1c2f6730 HD |
2153 | /* |
2154 | * An anonymous page must be locked, to ensure that a | |
2155 | * concurrent reuse_swap_page() sees stable mapcount; | |
2156 | * but reuse_swap_page() is not used on shmem or file, | |
2157 | * and page lock must not be taken when zap_pmd_range() | |
2158 | * calls __split_huge_pmd() while i_mmap_lock is held. | |
2159 | */ | |
af28a988 MWO |
2160 | if (folio_test_anon(folio)) { |
2161 | if (unlikely(!folio_trylock(folio))) { | |
2162 | folio_get(folio); | |
1c2f6730 HD |
2163 | _pmd = *pmd; |
2164 | spin_unlock(ptl); | |
af28a988 | 2165 | folio_lock(folio); |
1c2f6730 HD |
2166 | spin_lock(ptl); |
2167 | if (unlikely(!pmd_same(*pmd, _pmd))) { | |
af28a988 MWO |
2168 | folio_unlock(folio); |
2169 | folio_put(folio); | |
2170 | folio = NULL; | |
1c2f6730 HD |
2171 | goto repeat; |
2172 | } | |
af28a988 | 2173 | folio_put(folio); |
c444eb56 | 2174 | } |
af28a988 | 2175 | do_unlock_folio = true; |
c444eb56 AA |
2176 | } |
2177 | } | |
84c3fc4e | 2178 | } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) |
e90309c9 | 2179 | goto out; |
ac46d4f3 | 2180 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
e90309c9 | 2181 | out: |
eef1b3ba | 2182 | spin_unlock(ptl); |
af28a988 MWO |
2183 | if (do_unlock_folio) |
2184 | folio_unlock(folio); | |
4645b9fe JG |
2185 | /* |
2186 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2187 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2188 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2189 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2190 | * fault will trigger a flush_notify before pointing to a new page | |
2191 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2192 | * page in the meantime) | |
2193 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2194 | * to invalidate secondary tlb entry they are all still valid. | |
2195 | * any further changes to individual pte will notify. So no need | |
2196 | * to call mmu_notifier->invalidate_range() | |
2197 | */ | |
ac46d4f3 | 2198 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2199 | } |
2200 | ||
fec89c10 | 2201 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
af28a988 | 2202 | bool freeze, struct folio *folio) |
94fcc585 | 2203 | { |
f72e7dcd | 2204 | pgd_t *pgd; |
c2febafc | 2205 | p4d_t *p4d; |
f72e7dcd | 2206 | pud_t *pud; |
94fcc585 AA |
2207 | pmd_t *pmd; |
2208 | ||
78ddc534 | 2209 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2210 | if (!pgd_present(*pgd)) |
2211 | return; | |
2212 | ||
c2febafc KS |
2213 | p4d = p4d_offset(pgd, address); |
2214 | if (!p4d_present(*p4d)) | |
2215 | return; | |
2216 | ||
2217 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2218 | if (!pud_present(*pud)) |
2219 | return; | |
2220 | ||
2221 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2222 | |
af28a988 | 2223 | __split_huge_pmd(vma, pmd, address, freeze, folio); |
94fcc585 AA |
2224 | } |
2225 | ||
71f9e58e ML |
2226 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2227 | { | |
2228 | /* | |
2229 | * If the new address isn't hpage aligned and it could previously | |
2230 | * contain an hugepage: check if we need to split an huge pmd. | |
2231 | */ | |
2232 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2233 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2234 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2235 | split_huge_pmd_address(vma, address, false, NULL); | |
2236 | } | |
2237 | ||
e1b9996b | 2238 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2239 | unsigned long start, |
2240 | unsigned long end, | |
2241 | long adjust_next) | |
2242 | { | |
71f9e58e ML |
2243 | /* Check if we need to split start first. */ |
2244 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2245 | |
71f9e58e ML |
2246 | /* Check if we need to split end next. */ |
2247 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2248 | |
2249 | /* | |
71f9e58e ML |
2250 | * If we're also updating the vma->vm_next->vm_start, |
2251 | * check if we need to split it. | |
94fcc585 AA |
2252 | */ |
2253 | if (adjust_next > 0) { | |
2254 | struct vm_area_struct *next = vma->vm_next; | |
2255 | unsigned long nstart = next->vm_start; | |
f9d86a60 | 2256 | nstart += adjust_next; |
71f9e58e | 2257 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2258 | } |
2259 | } | |
e9b61f19 | 2260 | |
906f9cdf | 2261 | static void unmap_page(struct page *page) |
e9b61f19 | 2262 | { |
869f7ee6 | 2263 | struct folio *folio = page_folio(page); |
a98a2f0c AP |
2264 | enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | |
2265 | TTU_SYNC; | |
e9b61f19 KS |
2266 | |
2267 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2268 | ||
a98a2f0c AP |
2269 | /* |
2270 | * Anon pages need migration entries to preserve them, but file | |
2271 | * pages can simply be left unmapped, then faulted back on demand. | |
2272 | * If that is ever changed (perhaps for mlock), update remap_page(). | |
2273 | */ | |
4b8554c5 MWO |
2274 | if (folio_test_anon(folio)) |
2275 | try_to_migrate(folio, ttu_flags); | |
a98a2f0c | 2276 | else |
869f7ee6 | 2277 | try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); |
504e070d YS |
2278 | |
2279 | VM_WARN_ON_ONCE_PAGE(page_mapped(page), page); | |
e9b61f19 KS |
2280 | } |
2281 | ||
4eecb8b9 | 2282 | static void remap_page(struct folio *folio, unsigned long nr) |
e9b61f19 | 2283 | { |
4eecb8b9 | 2284 | int i = 0; |
ab02c252 | 2285 | |
64b586d1 | 2286 | /* If unmap_page() uses try_to_migrate() on file, remove this check */ |
4eecb8b9 | 2287 | if (!folio_test_anon(folio)) |
ab02c252 | 2288 | return; |
4eecb8b9 MWO |
2289 | for (;;) { |
2290 | remove_migration_ptes(folio, folio, true); | |
2291 | i += folio_nr_pages(folio); | |
2292 | if (i >= nr) | |
2293 | break; | |
2294 | folio = folio_next(folio); | |
ace71a19 | 2295 | } |
e9b61f19 KS |
2296 | } |
2297 | ||
94866635 | 2298 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2299 | struct lruvec *lruvec, struct list_head *list) |
2300 | { | |
94866635 AS |
2301 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2302 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2303 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2304 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2305 | |
6dbb5741 | 2306 | if (list) { |
88dcb9a3 | 2307 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2308 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2309 | get_page(tail); |
2310 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2311 | } else { |
6dbb5741 AS |
2312 | /* head is still on lru (and we have it frozen) */ |
2313 | VM_WARN_ON(!PageLRU(head)); | |
07ca7606 HD |
2314 | if (PageUnevictable(tail)) |
2315 | tail->mlock_count = 0; | |
2316 | else | |
2317 | list_add_tail(&tail->lru, &head->lru); | |
6dbb5741 | 2318 | SetPageLRU(tail); |
88dcb9a3 AS |
2319 | } |
2320 | } | |
2321 | ||
8df651c7 | 2322 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2323 | struct lruvec *lruvec, struct list_head *list) |
2324 | { | |
e9b61f19 KS |
2325 | struct page *page_tail = head + tail; |
2326 | ||
8df651c7 | 2327 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2328 | |
2329 | /* | |
605ca5ed KK |
2330 | * Clone page flags before unfreezing refcount. |
2331 | * | |
2332 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2333 | * for example lock_page() which set PG_waiters. |
e9b61f19 | 2334 | */ |
e9b61f19 KS |
2335 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2336 | page_tail->flags |= (head->flags & | |
2337 | ((1L << PG_referenced) | | |
2338 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2339 | (1L << PG_swapcache) | |
e9b61f19 KS |
2340 | (1L << PG_mlocked) | |
2341 | (1L << PG_uptodate) | | |
2342 | (1L << PG_active) | | |
1899ad18 | 2343 | (1L << PG_workingset) | |
e9b61f19 | 2344 | (1L << PG_locked) | |
b8d3c4c3 | 2345 | (1L << PG_unevictable) | |
72e6afa0 CM |
2346 | #ifdef CONFIG_64BIT |
2347 | (1L << PG_arch_2) | | |
2348 | #endif | |
b8d3c4c3 | 2349 | (1L << PG_dirty))); |
e9b61f19 | 2350 | |
173d9d9f HD |
2351 | /* ->mapping in first tail page is compound_mapcount */ |
2352 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2353 | page_tail); | |
2354 | page_tail->mapping = head->mapping; | |
2355 | page_tail->index = head->index + tail; | |
2356 | ||
605ca5ed | 2357 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2358 | smp_wmb(); |
2359 | ||
605ca5ed KK |
2360 | /* |
2361 | * Clear PageTail before unfreezing page refcount. | |
2362 | * | |
2363 | * After successful get_page_unless_zero() might follow put_page() | |
2364 | * which needs correct compound_head(). | |
2365 | */ | |
e9b61f19 KS |
2366 | clear_compound_head(page_tail); |
2367 | ||
605ca5ed KK |
2368 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2369 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2370 | PageSwapCache(head))); | |
2371 | ||
e9b61f19 KS |
2372 | if (page_is_young(head)) |
2373 | set_page_young(page_tail); | |
2374 | if (page_is_idle(head)) | |
2375 | set_page_idle(page_tail); | |
2376 | ||
e9b61f19 | 2377 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2378 | |
2379 | /* | |
2380 | * always add to the tail because some iterators expect new | |
2381 | * pages to show after the currently processed elements - e.g. | |
2382 | * migrate_pages | |
2383 | */ | |
e9b61f19 | 2384 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2385 | } |
2386 | ||
baa355fd | 2387 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2388 | pgoff_t end) |
e9b61f19 | 2389 | { |
e809c3fe MWO |
2390 | struct folio *folio = page_folio(page); |
2391 | struct page *head = &folio->page; | |
e9b61f19 | 2392 | struct lruvec *lruvec; |
4101196b MWO |
2393 | struct address_space *swap_cache = NULL; |
2394 | unsigned long offset = 0; | |
8cce5475 | 2395 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2396 | int i; |
e9b61f19 | 2397 | |
e9b61f19 | 2398 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2399 | split_page_memcg(head, nr); |
e9b61f19 | 2400 | |
4101196b MWO |
2401 | if (PageAnon(head) && PageSwapCache(head)) { |
2402 | swp_entry_t entry = { .val = page_private(head) }; | |
2403 | ||
2404 | offset = swp_offset(entry); | |
2405 | swap_cache = swap_address_space(entry); | |
2406 | xa_lock(&swap_cache->i_pages); | |
2407 | } | |
2408 | ||
f0953a1b | 2409 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
e809c3fe | 2410 | lruvec = folio_lruvec_lock(folio); |
b6769834 | 2411 | |
eac96c3e YS |
2412 | ClearPageHasHWPoisoned(head); |
2413 | ||
8cce5475 | 2414 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2415 | __split_huge_page_tail(head, i, lruvec, list); |
d144bf62 | 2416 | /* Some pages can be beyond EOF: drop them from page cache */ |
baa355fd | 2417 | if (head[i].index >= end) { |
2d077d4b | 2418 | ClearPageDirty(head + i); |
baa355fd | 2419 | __delete_from_page_cache(head + i, NULL); |
d144bf62 | 2420 | if (shmem_mapping(head->mapping)) |
800d8c63 | 2421 | shmem_uncharge(head->mapping->host, 1); |
baa355fd | 2422 | put_page(head + i); |
4101196b MWO |
2423 | } else if (!PageAnon(page)) { |
2424 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2425 | head + i, 0); | |
2426 | } else if (swap_cache) { | |
2427 | __xa_store(&swap_cache->i_pages, offset + i, | |
2428 | head + i, 0); | |
baa355fd KS |
2429 | } |
2430 | } | |
e9b61f19 KS |
2431 | |
2432 | ClearPageCompound(head); | |
6168d0da | 2433 | unlock_page_lruvec(lruvec); |
b6769834 | 2434 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2435 | |
8cce5475 | 2436 | split_page_owner(head, nr); |
f7da677b | 2437 | |
baa355fd KS |
2438 | /* See comment in __split_huge_page_tail() */ |
2439 | if (PageAnon(head)) { | |
aa5dc07f | 2440 | /* Additional pin to swap cache */ |
4101196b | 2441 | if (PageSwapCache(head)) { |
38d8b4e6 | 2442 | page_ref_add(head, 2); |
4101196b MWO |
2443 | xa_unlock(&swap_cache->i_pages); |
2444 | } else { | |
38d8b4e6 | 2445 | page_ref_inc(head); |
4101196b | 2446 | } |
baa355fd | 2447 | } else { |
aa5dc07f | 2448 | /* Additional pin to page cache */ |
baa355fd | 2449 | page_ref_add(head, 2); |
b93b0163 | 2450 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2451 | } |
b6769834 | 2452 | local_irq_enable(); |
e9b61f19 | 2453 | |
4eecb8b9 | 2454 | remap_page(folio, nr); |
e9b61f19 | 2455 | |
c4f9c701 HY |
2456 | if (PageSwapCache(head)) { |
2457 | swp_entry_t entry = { .val = page_private(head) }; | |
2458 | ||
2459 | split_swap_cluster(entry); | |
2460 | } | |
2461 | ||
8cce5475 | 2462 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2463 | struct page *subpage = head + i; |
2464 | if (subpage == page) | |
2465 | continue; | |
2466 | unlock_page(subpage); | |
2467 | ||
2468 | /* | |
2469 | * Subpages may be freed if there wasn't any mapping | |
2470 | * like if add_to_swap() is running on a lru page that | |
2471 | * had its mapping zapped. And freeing these pages | |
2472 | * requires taking the lru_lock so we do the put_page | |
2473 | * of the tail pages after the split is complete. | |
2474 | */ | |
2475 | put_page(subpage); | |
2476 | } | |
2477 | } | |
2478 | ||
6d0a07ed AA |
2479 | /* |
2480 | * This calculates accurately how many mappings a transparent hugepage | |
2481 | * has (unlike page_mapcount() which isn't fully accurate). This full | |
2482 | * accuracy is primarily needed to know if copy-on-write faults can | |
2483 | * reuse the page and change the mapping to read-write instead of | |
2484 | * copying them. At the same time this returns the total_mapcount too. | |
2485 | * | |
2486 | * The function returns the highest mapcount any one of the subpages | |
2487 | * has. If the return value is one, even if different processes are | |
2488 | * mapping different subpages of the transparent hugepage, they can | |
2489 | * all reuse it, because each process is reusing a different subpage. | |
2490 | * | |
2491 | * The total_mapcount is instead counting all virtual mappings of the | |
2492 | * subpages. If the total_mapcount is equal to "one", it tells the | |
2493 | * caller all mappings belong to the same "mm" and in turn the | |
2494 | * anon_vma of the transparent hugepage can become the vma->anon_vma | |
2495 | * local one as no other process may be mapping any of the subpages. | |
2496 | * | |
2497 | * It would be more accurate to replace page_mapcount() with | |
2498 | * page_trans_huge_mapcount(), however we only use | |
2499 | * page_trans_huge_mapcount() in the copy-on-write faults where we | |
2500 | * need full accuracy to avoid breaking page pinning, because | |
2501 | * page_trans_huge_mapcount() is slower than page_mapcount(). | |
2502 | */ | |
d08d2b62 | 2503 | int page_trans_huge_mapcount(struct page *page) |
6d0a07ed | 2504 | { |
d08d2b62 | 2505 | int i, ret; |
6d0a07ed AA |
2506 | |
2507 | /* hugetlbfs shouldn't call it */ | |
2508 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
2509 | ||
d08d2b62 MWO |
2510 | if (likely(!PageTransCompound(page))) |
2511 | return atomic_read(&page->_mapcount) + 1; | |
6d0a07ed AA |
2512 | |
2513 | page = compound_head(page); | |
2514 | ||
d08d2b62 | 2515 | ret = 0; |
65dfe3c3 | 2516 | for (i = 0; i < thp_nr_pages(page); i++) { |
d08d2b62 | 2517 | int mapcount = atomic_read(&page[i]._mapcount) + 1; |
6d0a07ed | 2518 | ret = max(ret, mapcount); |
6d0a07ed | 2519 | } |
d08d2b62 MWO |
2520 | |
2521 | if (PageDoubleMap(page)) | |
6d0a07ed | 2522 | ret -= 1; |
d08d2b62 MWO |
2523 | |
2524 | return ret + compound_mapcount(page); | |
6d0a07ed AA |
2525 | } |
2526 | ||
b8f593cd | 2527 | /* Racy check whether the huge page can be split */ |
d4b4084a | 2528 | bool can_split_folio(struct folio *folio, int *pextra_pins) |
b8f593cd HY |
2529 | { |
2530 | int extra_pins; | |
2531 | ||
aa5dc07f | 2532 | /* Additional pins from page cache */ |
d4b4084a MWO |
2533 | if (folio_test_anon(folio)) |
2534 | extra_pins = folio_test_swapcache(folio) ? | |
2535 | folio_nr_pages(folio) : 0; | |
b8f593cd | 2536 | else |
d4b4084a | 2537 | extra_pins = folio_nr_pages(folio); |
b8f593cd HY |
2538 | if (pextra_pins) |
2539 | *pextra_pins = extra_pins; | |
d4b4084a | 2540 | return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; |
b8f593cd HY |
2541 | } |
2542 | ||
e9b61f19 KS |
2543 | /* |
2544 | * This function splits huge page into normal pages. @page can point to any | |
2545 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2546 | * | |
2547 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2548 | * The huge page must be locked. | |
2549 | * | |
2550 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2551 | * | |
2552 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2553 | * the hugepage. | |
2554 | * | |
2555 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2556 | * they are not mapped. | |
2557 | * | |
2558 | * Returns 0 if the hugepage is split successfully. | |
2559 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2560 | * us. | |
2561 | */ | |
2562 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2563 | { | |
4eecb8b9 MWO |
2564 | struct folio *folio = page_folio(page); |
2565 | struct page *head = &folio->page; | |
a8803e6c | 2566 | struct deferred_split *ds_queue = get_deferred_split_queue(head); |
6b24ca4a | 2567 | XA_STATE(xas, &head->mapping->i_pages, head->index); |
baa355fd KS |
2568 | struct anon_vma *anon_vma = NULL; |
2569 | struct address_space *mapping = NULL; | |
504e070d | 2570 | int extra_pins, ret; |
006d3ff2 | 2571 | pgoff_t end; |
e9b61f19 | 2572 | |
cb829624 | 2573 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
a8803e6c WY |
2574 | VM_BUG_ON_PAGE(!PageLocked(head), head); |
2575 | VM_BUG_ON_PAGE(!PageCompound(head), head); | |
e9b61f19 | 2576 | |
a8803e6c | 2577 | if (PageWriteback(head)) |
59807685 HY |
2578 | return -EBUSY; |
2579 | ||
baa355fd KS |
2580 | if (PageAnon(head)) { |
2581 | /* | |
c1e8d7c6 | 2582 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2583 | * prevent the anon_vma disappearing so we first we take a |
2584 | * reference to it and then lock the anon_vma for write. This | |
2f031c6f | 2585 | * is similar to folio_lock_anon_vma_read except the write lock |
baa355fd KS |
2586 | * is taken to serialise against parallel split or collapse |
2587 | * operations. | |
2588 | */ | |
2589 | anon_vma = page_get_anon_vma(head); | |
2590 | if (!anon_vma) { | |
2591 | ret = -EBUSY; | |
2592 | goto out; | |
2593 | } | |
006d3ff2 | 2594 | end = -1; |
baa355fd KS |
2595 | mapping = NULL; |
2596 | anon_vma_lock_write(anon_vma); | |
2597 | } else { | |
2598 | mapping = head->mapping; | |
2599 | ||
2600 | /* Truncated ? */ | |
2601 | if (!mapping) { | |
2602 | ret = -EBUSY; | |
2603 | goto out; | |
2604 | } | |
2605 | ||
6b24ca4a MWO |
2606 | xas_split_alloc(&xas, head, compound_order(head), |
2607 | mapping_gfp_mask(mapping) & GFP_RECLAIM_MASK); | |
2608 | if (xas_error(&xas)) { | |
2609 | ret = xas_error(&xas); | |
2610 | goto out; | |
2611 | } | |
2612 | ||
baa355fd KS |
2613 | anon_vma = NULL; |
2614 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2615 | |
2616 | /* | |
2617 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2618 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2619 | * which cannot be nested inside the page tree lock. So note | |
2620 | * end now: i_size itself may be changed at any moment, but | |
2621 | * head page lock is good enough to serialize the trimming. | |
2622 | */ | |
2623 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
d144bf62 HD |
2624 | if (shmem_mapping(mapping)) |
2625 | end = shmem_fallocend(mapping->host, end); | |
e9b61f19 | 2626 | } |
e9b61f19 KS |
2627 | |
2628 | /* | |
906f9cdf | 2629 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2630 | * split PMDs |
2631 | */ | |
d4b4084a | 2632 | if (!can_split_folio(folio, &extra_pins)) { |
e9b61f19 KS |
2633 | ret = -EBUSY; |
2634 | goto out_unlock; | |
2635 | } | |
2636 | ||
906f9cdf | 2637 | unmap_page(head); |
e9b61f19 | 2638 | |
b6769834 AS |
2639 | /* block interrupt reentry in xa_lock and spinlock */ |
2640 | local_irq_disable(); | |
baa355fd | 2641 | if (mapping) { |
baa355fd | 2642 | /* |
aa5dc07f | 2643 | * Check if the head page is present in page cache. |
baa355fd KS |
2644 | * We assume all tail are present too, if head is there. |
2645 | */ | |
6b24ca4a MWO |
2646 | xas_lock(&xas); |
2647 | xas_reset(&xas); | |
aa5dc07f | 2648 | if (xas_load(&xas) != head) |
baa355fd KS |
2649 | goto fail; |
2650 | } | |
2651 | ||
0139aa7b | 2652 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2653 | spin_lock(&ds_queue->split_queue_lock); |
504e070d | 2654 | if (page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2655 | if (!list_empty(page_deferred_list(head))) { |
364c1eeb | 2656 | ds_queue->split_queue_len--; |
9a982250 KS |
2657 | list_del(page_deferred_list(head)); |
2658 | } | |
afb97172 | 2659 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2660 | if (mapping) { |
bf9ecead MS |
2661 | int nr = thp_nr_pages(head); |
2662 | ||
6b24ca4a | 2663 | xas_split(&xas, head, thp_order(head)); |
1ca7554d | 2664 | if (PageSwapBacked(head)) { |
57b2847d MS |
2665 | __mod_lruvec_page_state(head, NR_SHMEM_THPS, |
2666 | -nr); | |
1ca7554d | 2667 | } else { |
bf9ecead MS |
2668 | __mod_lruvec_page_state(head, NR_FILE_THPS, |
2669 | -nr); | |
1ca7554d MS |
2670 | filemap_nr_thps_dec(mapping); |
2671 | } | |
06d3eff6 KS |
2672 | } |
2673 | ||
b6769834 | 2674 | __split_huge_page(page, list, end); |
c4f9c701 | 2675 | ret = 0; |
e9b61f19 | 2676 | } else { |
364c1eeb | 2677 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2678 | fail: |
2679 | if (mapping) | |
6b24ca4a | 2680 | xas_unlock(&xas); |
b6769834 | 2681 | local_irq_enable(); |
4eecb8b9 | 2682 | remap_page(folio, folio_nr_pages(folio)); |
e9b61f19 KS |
2683 | ret = -EBUSY; |
2684 | } | |
2685 | ||
2686 | out_unlock: | |
baa355fd KS |
2687 | if (anon_vma) { |
2688 | anon_vma_unlock_write(anon_vma); | |
2689 | put_anon_vma(anon_vma); | |
2690 | } | |
2691 | if (mapping) | |
2692 | i_mmap_unlock_read(mapping); | |
e9b61f19 | 2693 | out: |
6b24ca4a MWO |
2694 | /* Free any memory we didn't use */ |
2695 | xas_nomem(&xas, 0); | |
e9b61f19 KS |
2696 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); |
2697 | return ret; | |
2698 | } | |
9a982250 KS |
2699 | |
2700 | void free_transhuge_page(struct page *page) | |
2701 | { | |
87eaceb3 | 2702 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2703 | unsigned long flags; |
2704 | ||
364c1eeb | 2705 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2706 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2707 | ds_queue->split_queue_len--; |
9a982250 KS |
2708 | list_del(page_deferred_list(page)); |
2709 | } | |
364c1eeb | 2710 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2711 | free_compound_page(page); |
2712 | } | |
2713 | ||
2714 | void deferred_split_huge_page(struct page *page) | |
2715 | { | |
87eaceb3 YS |
2716 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2717 | #ifdef CONFIG_MEMCG | |
bcfe06bf | 2718 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 | 2719 | #endif |
9a982250 KS |
2720 | unsigned long flags; |
2721 | ||
2722 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2723 | ||
87eaceb3 YS |
2724 | /* |
2725 | * The try_to_unmap() in page reclaim path might reach here too, | |
2726 | * this may cause a race condition to corrupt deferred split queue. | |
2727 | * And, if page reclaim is already handling the same page, it is | |
2728 | * unnecessary to handle it again in shrinker. | |
2729 | * | |
2730 | * Check PageSwapCache to determine if the page is being | |
2731 | * handled by page reclaim since THP swap would add the page into | |
2732 | * swap cache before calling try_to_unmap(). | |
2733 | */ | |
2734 | if (PageSwapCache(page)) | |
2735 | return; | |
2736 | ||
364c1eeb | 2737 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2738 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2739 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2740 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2741 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2742 | #ifdef CONFIG_MEMCG |
2743 | if (memcg) | |
2bfd3637 YS |
2744 | set_shrinker_bit(memcg, page_to_nid(page), |
2745 | deferred_split_shrinker.id); | |
87eaceb3 | 2746 | #endif |
9a982250 | 2747 | } |
364c1eeb | 2748 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2749 | } |
2750 | ||
2751 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2752 | struct shrink_control *sc) | |
2753 | { | |
a3d0a918 | 2754 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2755 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2756 | |
2757 | #ifdef CONFIG_MEMCG | |
2758 | if (sc->memcg) | |
2759 | ds_queue = &sc->memcg->deferred_split_queue; | |
2760 | #endif | |
364c1eeb | 2761 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2762 | } |
2763 | ||
2764 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2765 | struct shrink_control *sc) | |
2766 | { | |
a3d0a918 | 2767 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2768 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2769 | unsigned long flags; |
2770 | LIST_HEAD(list), *pos, *next; | |
2771 | struct page *page; | |
2772 | int split = 0; | |
2773 | ||
87eaceb3 YS |
2774 | #ifdef CONFIG_MEMCG |
2775 | if (sc->memcg) | |
2776 | ds_queue = &sc->memcg->deferred_split_queue; | |
2777 | #endif | |
2778 | ||
364c1eeb | 2779 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2780 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2781 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
dfe5c51c | 2782 | page = list_entry((void *)pos, struct page, deferred_list); |
9a982250 | 2783 | page = compound_head(page); |
e3ae1953 KS |
2784 | if (get_page_unless_zero(page)) { |
2785 | list_move(page_deferred_list(page), &list); | |
2786 | } else { | |
2787 | /* We lost race with put_compound_page() */ | |
9a982250 | 2788 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2789 | ds_queue->split_queue_len--; |
9a982250 | 2790 | } |
e3ae1953 KS |
2791 | if (!--sc->nr_to_scan) |
2792 | break; | |
9a982250 | 2793 | } |
364c1eeb | 2794 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2795 | |
2796 | list_for_each_safe(pos, next, &list) { | |
dfe5c51c | 2797 | page = list_entry((void *)pos, struct page, deferred_list); |
fa41b900 KS |
2798 | if (!trylock_page(page)) |
2799 | goto next; | |
9a982250 KS |
2800 | /* split_huge_page() removes page from list on success */ |
2801 | if (!split_huge_page(page)) | |
2802 | split++; | |
2803 | unlock_page(page); | |
fa41b900 | 2804 | next: |
9a982250 KS |
2805 | put_page(page); |
2806 | } | |
2807 | ||
364c1eeb YS |
2808 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2809 | list_splice_tail(&list, &ds_queue->split_queue); | |
2810 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2811 | |
cb8d68ec KS |
2812 | /* |
2813 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2814 | * This can happen if pages were freed under us. | |
2815 | */ | |
364c1eeb | 2816 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2817 | return SHRINK_STOP; |
2818 | return split; | |
9a982250 KS |
2819 | } |
2820 | ||
2821 | static struct shrinker deferred_split_shrinker = { | |
2822 | .count_objects = deferred_split_count, | |
2823 | .scan_objects = deferred_split_scan, | |
2824 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2825 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2826 | SHRINKER_NONSLAB, | |
9a982250 | 2827 | }; |
49071d43 KS |
2828 | |
2829 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2830 | static void split_huge_pages_all(void) |
49071d43 KS |
2831 | { |
2832 | struct zone *zone; | |
2833 | struct page *page; | |
2834 | unsigned long pfn, max_zone_pfn; | |
2835 | unsigned long total = 0, split = 0; | |
2836 | ||
fa6c0231 | 2837 | pr_debug("Split all THPs\n"); |
49071d43 KS |
2838 | for_each_populated_zone(zone) { |
2839 | max_zone_pfn = zone_end_pfn(zone); | |
2840 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2841 | if (!pfn_valid(pfn)) | |
2842 | continue; | |
2843 | ||
2844 | page = pfn_to_page(pfn); | |
2845 | if (!get_page_unless_zero(page)) | |
2846 | continue; | |
2847 | ||
2848 | if (zone != page_zone(page)) | |
2849 | goto next; | |
2850 | ||
baa355fd | 2851 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2852 | goto next; |
2853 | ||
2854 | total++; | |
2855 | lock_page(page); | |
2856 | if (!split_huge_page(page)) | |
2857 | split++; | |
2858 | unlock_page(page); | |
2859 | next: | |
2860 | put_page(page); | |
fa6c0231 | 2861 | cond_resched(); |
49071d43 KS |
2862 | } |
2863 | } | |
2864 | ||
fa6c0231 ZY |
2865 | pr_debug("%lu of %lu THP split\n", split, total); |
2866 | } | |
49071d43 | 2867 | |
fa6c0231 ZY |
2868 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2869 | { | |
2870 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2871 | is_vm_hugetlb_page(vma); | |
2872 | } | |
2873 | ||
2874 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2875 | unsigned long vaddr_end) | |
2876 | { | |
2877 | int ret = 0; | |
2878 | struct task_struct *task; | |
2879 | struct mm_struct *mm; | |
2880 | unsigned long total = 0, split = 0; | |
2881 | unsigned long addr; | |
2882 | ||
2883 | vaddr_start &= PAGE_MASK; | |
2884 | vaddr_end &= PAGE_MASK; | |
2885 | ||
2886 | /* Find the task_struct from pid */ | |
2887 | rcu_read_lock(); | |
2888 | task = find_task_by_vpid(pid); | |
2889 | if (!task) { | |
2890 | rcu_read_unlock(); | |
2891 | ret = -ESRCH; | |
2892 | goto out; | |
2893 | } | |
2894 | get_task_struct(task); | |
2895 | rcu_read_unlock(); | |
2896 | ||
2897 | /* Find the mm_struct */ | |
2898 | mm = get_task_mm(task); | |
2899 | put_task_struct(task); | |
2900 | ||
2901 | if (!mm) { | |
2902 | ret = -EINVAL; | |
2903 | goto out; | |
2904 | } | |
2905 | ||
2906 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
2907 | pid, vaddr_start, vaddr_end); | |
2908 | ||
2909 | mmap_read_lock(mm); | |
2910 | /* | |
2911 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
2912 | * table filled with PTE-mapped THPs, each of which is distinct. | |
2913 | */ | |
2914 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
2915 | struct vm_area_struct *vma = find_vma(mm, addr); | |
fa6c0231 ZY |
2916 | struct page *page; |
2917 | ||
2918 | if (!vma || addr < vma->vm_start) | |
2919 | break; | |
2920 | ||
2921 | /* skip special VMA and hugetlb VMA */ | |
2922 | if (vma_not_suitable_for_thp_split(vma)) { | |
2923 | addr = vma->vm_end; | |
2924 | continue; | |
2925 | } | |
2926 | ||
2927 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
87d2762e | 2928 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
fa6c0231 ZY |
2929 | |
2930 | if (IS_ERR(page)) | |
2931 | continue; | |
2932 | if (!page) | |
2933 | continue; | |
2934 | ||
2935 | if (!is_transparent_hugepage(page)) | |
2936 | goto next; | |
2937 | ||
2938 | total++; | |
d4b4084a | 2939 | if (!can_split_folio(page_folio(page), NULL)) |
fa6c0231 ZY |
2940 | goto next; |
2941 | ||
2942 | if (!trylock_page(page)) | |
2943 | goto next; | |
2944 | ||
2945 | if (!split_huge_page(page)) | |
2946 | split++; | |
2947 | ||
2948 | unlock_page(page); | |
2949 | next: | |
2950 | put_page(page); | |
2951 | cond_resched(); | |
2952 | } | |
2953 | mmap_read_unlock(mm); | |
2954 | mmput(mm); | |
2955 | ||
2956 | pr_debug("%lu of %lu THP split\n", split, total); | |
2957 | ||
2958 | out: | |
2959 | return ret; | |
49071d43 | 2960 | } |
fa6c0231 | 2961 | |
fbe37501 ZY |
2962 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
2963 | pgoff_t off_end) | |
2964 | { | |
2965 | struct filename *file; | |
2966 | struct file *candidate; | |
2967 | struct address_space *mapping; | |
2968 | int ret = -EINVAL; | |
2969 | pgoff_t index; | |
2970 | int nr_pages = 1; | |
2971 | unsigned long total = 0, split = 0; | |
2972 | ||
2973 | file = getname_kernel(file_path); | |
2974 | if (IS_ERR(file)) | |
2975 | return ret; | |
2976 | ||
2977 | candidate = file_open_name(file, O_RDONLY, 0); | |
2978 | if (IS_ERR(candidate)) | |
2979 | goto out; | |
2980 | ||
2981 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
2982 | file_path, off_start, off_end); | |
2983 | ||
2984 | mapping = candidate->f_mapping; | |
2985 | ||
2986 | for (index = off_start; index < off_end; index += nr_pages) { | |
2987 | struct page *fpage = pagecache_get_page(mapping, index, | |
2988 | FGP_ENTRY | FGP_HEAD, 0); | |
2989 | ||
2990 | nr_pages = 1; | |
2991 | if (xa_is_value(fpage) || !fpage) | |
2992 | continue; | |
2993 | ||
2994 | if (!is_transparent_hugepage(fpage)) | |
2995 | goto next; | |
2996 | ||
2997 | total++; | |
2998 | nr_pages = thp_nr_pages(fpage); | |
2999 | ||
3000 | if (!trylock_page(fpage)) | |
3001 | goto next; | |
3002 | ||
3003 | if (!split_huge_page(fpage)) | |
3004 | split++; | |
3005 | ||
3006 | unlock_page(fpage); | |
3007 | next: | |
3008 | put_page(fpage); | |
3009 | cond_resched(); | |
3010 | } | |
3011 | ||
3012 | filp_close(candidate, NULL); | |
3013 | ret = 0; | |
3014 | ||
3015 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3016 | out: | |
3017 | putname(file); | |
3018 | return ret; | |
3019 | } | |
3020 | ||
fa6c0231 ZY |
3021 | #define MAX_INPUT_BUF_SZ 255 |
3022 | ||
3023 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3024 | size_t count, loff_t *ppops) | |
3025 | { | |
3026 | static DEFINE_MUTEX(split_debug_mutex); | |
3027 | ssize_t ret; | |
fbe37501 ZY |
3028 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3029 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3030 | int pid; |
3031 | unsigned long vaddr_start, vaddr_end; | |
3032 | ||
3033 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3034 | if (ret) | |
3035 | return ret; | |
3036 | ||
3037 | ret = -EFAULT; | |
3038 | ||
3039 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3040 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3041 | goto out; | |
3042 | ||
3043 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3044 | |
3045 | if (input_buf[0] == '/') { | |
3046 | char *tok; | |
3047 | char *buf = input_buf; | |
3048 | char file_path[MAX_INPUT_BUF_SZ]; | |
3049 | pgoff_t off_start = 0, off_end = 0; | |
3050 | size_t input_len = strlen(input_buf); | |
3051 | ||
3052 | tok = strsep(&buf, ","); | |
3053 | if (tok) { | |
1212e00c | 3054 | strcpy(file_path, tok); |
fbe37501 ZY |
3055 | } else { |
3056 | ret = -EINVAL; | |
3057 | goto out; | |
3058 | } | |
3059 | ||
3060 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3061 | if (ret != 2) { | |
3062 | ret = -EINVAL; | |
3063 | goto out; | |
3064 | } | |
3065 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3066 | if (!ret) | |
3067 | ret = input_len; | |
3068 | ||
3069 | goto out; | |
3070 | } | |
3071 | ||
fa6c0231 ZY |
3072 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3073 | if (ret == 1 && pid == 1) { | |
3074 | split_huge_pages_all(); | |
3075 | ret = strlen(input_buf); | |
3076 | goto out; | |
3077 | } else if (ret != 3) { | |
3078 | ret = -EINVAL; | |
3079 | goto out; | |
3080 | } | |
3081 | ||
3082 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3083 | if (!ret) | |
3084 | ret = strlen(input_buf); | |
3085 | out: | |
3086 | mutex_unlock(&split_debug_mutex); | |
3087 | return ret; | |
3088 | ||
3089 | } | |
3090 | ||
3091 | static const struct file_operations split_huge_pages_fops = { | |
3092 | .owner = THIS_MODULE, | |
3093 | .write = split_huge_pages_write, | |
3094 | .llseek = no_llseek, | |
3095 | }; | |
49071d43 KS |
3096 | |
3097 | static int __init split_huge_pages_debugfs(void) | |
3098 | { | |
d9f7979c GKH |
3099 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3100 | &split_huge_pages_fops); | |
49071d43 KS |
3101 | return 0; |
3102 | } | |
3103 | late_initcall(split_huge_pages_debugfs); | |
3104 | #endif | |
616b8371 ZY |
3105 | |
3106 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
3107 | void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, | |
3108 | struct page *page) | |
3109 | { | |
3110 | struct vm_area_struct *vma = pvmw->vma; | |
3111 | struct mm_struct *mm = vma->vm_mm; | |
3112 | unsigned long address = pvmw->address; | |
3113 | pmd_t pmdval; | |
3114 | swp_entry_t entry; | |
ab6e3d09 | 3115 | pmd_t pmdswp; |
616b8371 ZY |
3116 | |
3117 | if (!(pvmw->pmd && !pvmw->pte)) | |
3118 | return; | |
3119 | ||
616b8371 | 3120 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3121 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
616b8371 ZY |
3122 | if (pmd_dirty(pmdval)) |
3123 | set_page_dirty(page); | |
4dd845b5 AP |
3124 | if (pmd_write(pmdval)) |
3125 | entry = make_writable_migration_entry(page_to_pfn(page)); | |
3126 | else | |
3127 | entry = make_readable_migration_entry(page_to_pfn(page)); | |
ab6e3d09 NH |
3128 | pmdswp = swp_entry_to_pmd(entry); |
3129 | if (pmd_soft_dirty(pmdval)) | |
3130 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3131 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
cea86fe2 | 3132 | page_remove_rmap(page, vma, true); |
616b8371 | 3133 | put_page(page); |
616b8371 ZY |
3134 | } |
3135 | ||
3136 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3137 | { | |
3138 | struct vm_area_struct *vma = pvmw->vma; | |
3139 | struct mm_struct *mm = vma->vm_mm; | |
3140 | unsigned long address = pvmw->address; | |
3141 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
3142 | pmd_t pmde; | |
3143 | swp_entry_t entry; | |
3144 | ||
3145 | if (!(pvmw->pmd && !pvmw->pte)) | |
3146 | return; | |
3147 | ||
3148 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3149 | get_page(new); | |
3150 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
3151 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3152 | pmde = pmd_mksoft_dirty(pmde); | |
4dd845b5 | 3153 | if (is_writable_migration_entry(entry)) |
f55e1014 | 3154 | pmde = maybe_pmd_mkwrite(pmde, vma); |
8f34f1ea PX |
3155 | if (pmd_swp_uffd_wp(*pvmw->pmd)) |
3156 | pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); | |
616b8371 | 3157 | |
e71769ae NH |
3158 | if (PageAnon(new)) |
3159 | page_add_anon_rmap(new, vma, mmun_start, true); | |
3160 | else | |
cea86fe2 | 3161 | page_add_file_rmap(new, vma, true); |
616b8371 | 3162 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
5cbcf225 MS |
3163 | |
3164 | /* No need to invalidate - it was non-present before */ | |
616b8371 ZY |
3165 | update_mmu_cache_pmd(vma, address, pvmw->pmd); |
3166 | } | |
3167 | #endif |