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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" | |
014bb1de | 42 | #include "swap.h" |
71e3aac0 | 43 | |
283fd6fe AK |
44 | #define CREATE_TRACE_POINTS |
45 | #include <trace/events/thp.h> | |
46 | ||
ba76149f | 47 | /* |
b14d595a MD |
48 | * By default, transparent hugepage support is disabled in order to avoid |
49 | * risking an increased memory footprint for applications that are not | |
50 | * guaranteed to benefit from it. When transparent hugepage support is | |
51 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
52 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
53 | * for all hugepage allocations. | |
ba76149f | 54 | */ |
71e3aac0 | 55 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 56 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 57 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
58 | #endif |
59 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
60 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
61 | #endif | |
444eb2a4 | 62 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
63 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
64 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 65 | |
9a982250 | 66 | static struct shrinker deferred_split_shrinker; |
f000565a | 67 | |
97ae1749 | 68 | static atomic_t huge_zero_refcount; |
56873f43 | 69 | struct page *huge_zero_page __read_mostly; |
3b77e8c8 | 70 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 71 | |
e6be37b2 ML |
72 | static inline bool file_thp_enabled(struct vm_area_struct *vma) |
73 | { | |
74 | return transhuge_vma_enabled(vma, vma->vm_flags) && vma->vm_file && | |
75 | !inode_is_open_for_write(vma->vm_file->f_inode) && | |
76 | (vma->vm_flags & VM_EXEC); | |
77 | } | |
78 | ||
79 | bool transparent_hugepage_active(struct vm_area_struct *vma) | |
7635d9cb | 80 | { |
c0630669 YS |
81 | /* The addr is used to check if the vma size fits */ |
82 | unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE; | |
83 | ||
84 | if (!transhuge_vma_suitable(vma, addr)) | |
85 | return false; | |
7635d9cb MH |
86 | if (vma_is_anonymous(vma)) |
87 | return __transparent_hugepage_enabled(vma); | |
c0630669 YS |
88 | if (vma_is_shmem(vma)) |
89 | return shmem_huge_enabled(vma); | |
e6be37b2 ML |
90 | if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS)) |
91 | return file_thp_enabled(vma); | |
7635d9cb MH |
92 | |
93 | return false; | |
94 | } | |
95 | ||
aaa9705b | 96 | static bool get_huge_zero_page(void) |
97ae1749 KS |
97 | { |
98 | struct page *zero_page; | |
99 | retry: | |
100 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 101 | return true; |
97ae1749 KS |
102 | |
103 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 104 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
105 | if (!zero_page) { |
106 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 107 | return false; |
d8a8e1f0 KS |
108 | } |
109 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 110 | preempt_disable(); |
5918d10a | 111 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 112 | preempt_enable(); |
5ddacbe9 | 113 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
114 | goto retry; |
115 | } | |
3b77e8c8 | 116 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
117 | |
118 | /* We take additional reference here. It will be put back by shrinker */ | |
119 | atomic_set(&huge_zero_refcount, 2); | |
120 | preempt_enable(); | |
aaa9705b | 121 | return true; |
4a6c1297 KS |
122 | } |
123 | ||
6fcb52a5 | 124 | static void put_huge_zero_page(void) |
4a6c1297 | 125 | { |
97ae1749 KS |
126 | /* |
127 | * Counter should never go to zero here. Only shrinker can put | |
128 | * last reference. | |
129 | */ | |
130 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
131 | } |
132 | ||
6fcb52a5 AL |
133 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
134 | { | |
135 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
136 | return READ_ONCE(huge_zero_page); | |
137 | ||
138 | if (!get_huge_zero_page()) | |
139 | return NULL; | |
140 | ||
141 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
142 | put_huge_zero_page(); | |
143 | ||
144 | return READ_ONCE(huge_zero_page); | |
145 | } | |
146 | ||
147 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
148 | { | |
149 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
150 | put_huge_zero_page(); | |
151 | } | |
152 | ||
48896466 GC |
153 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
154 | struct shrink_control *sc) | |
4a6c1297 | 155 | { |
48896466 GC |
156 | /* we can free zero page only if last reference remains */ |
157 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
158 | } | |
97ae1749 | 159 | |
48896466 GC |
160 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
161 | struct shrink_control *sc) | |
162 | { | |
97ae1749 | 163 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
164 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
165 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 166 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 167 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 168 | return HPAGE_PMD_NR; |
97ae1749 KS |
169 | } |
170 | ||
171 | return 0; | |
4a6c1297 KS |
172 | } |
173 | ||
97ae1749 | 174 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
175 | .count_objects = shrink_huge_zero_page_count, |
176 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
177 | .seeks = DEFAULT_SEEKS, |
178 | }; | |
179 | ||
71e3aac0 | 180 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
181 | static ssize_t enabled_show(struct kobject *kobj, |
182 | struct kobj_attribute *attr, char *buf) | |
183 | { | |
bfb0ffeb JP |
184 | const char *output; |
185 | ||
444eb2a4 | 186 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
187 | output = "[always] madvise never"; |
188 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
189 | &transparent_hugepage_flags)) | |
190 | output = "always [madvise] never"; | |
444eb2a4 | 191 | else |
bfb0ffeb JP |
192 | output = "always madvise [never]"; |
193 | ||
194 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 195 | } |
444eb2a4 | 196 | |
71e3aac0 AA |
197 | static ssize_t enabled_store(struct kobject *kobj, |
198 | struct kobj_attribute *attr, | |
199 | const char *buf, size_t count) | |
200 | { | |
21440d7e | 201 | ssize_t ret = count; |
ba76149f | 202 | |
f42f2552 | 203 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
204 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
205 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 206 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
207 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
208 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 209 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
210 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
211 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
212 | } else | |
213 | ret = -EINVAL; | |
ba76149f AA |
214 | |
215 | if (ret > 0) { | |
b46e756f | 216 | int err = start_stop_khugepaged(); |
ba76149f AA |
217 | if (err) |
218 | ret = err; | |
219 | } | |
ba76149f | 220 | return ret; |
71e3aac0 AA |
221 | } |
222 | static struct kobj_attribute enabled_attr = | |
223 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
224 | ||
b46e756f | 225 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
226 | struct kobj_attribute *attr, char *buf, |
227 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 228 | { |
bfb0ffeb JP |
229 | return sysfs_emit(buf, "%d\n", |
230 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 231 | } |
e27e6151 | 232 | |
b46e756f | 233 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
234 | struct kobj_attribute *attr, |
235 | const char *buf, size_t count, | |
236 | enum transparent_hugepage_flag flag) | |
237 | { | |
e27e6151 BH |
238 | unsigned long value; |
239 | int ret; | |
240 | ||
241 | ret = kstrtoul(buf, 10, &value); | |
242 | if (ret < 0) | |
243 | return ret; | |
244 | if (value > 1) | |
245 | return -EINVAL; | |
246 | ||
247 | if (value) | |
71e3aac0 | 248 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 249 | else |
71e3aac0 | 250 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
251 | |
252 | return count; | |
253 | } | |
254 | ||
71e3aac0 AA |
255 | static ssize_t defrag_show(struct kobject *kobj, |
256 | struct kobj_attribute *attr, char *buf) | |
257 | { | |
bfb0ffeb JP |
258 | const char *output; |
259 | ||
260 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
261 | &transparent_hugepage_flags)) | |
262 | output = "[always] defer defer+madvise madvise never"; | |
263 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
264 | &transparent_hugepage_flags)) | |
265 | output = "always [defer] defer+madvise madvise never"; | |
266 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
267 | &transparent_hugepage_flags)) | |
268 | output = "always defer [defer+madvise] madvise never"; | |
269 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
270 | &transparent_hugepage_flags)) | |
271 | output = "always defer defer+madvise [madvise] never"; | |
272 | else | |
273 | output = "always defer defer+madvise madvise [never]"; | |
274 | ||
275 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 276 | } |
21440d7e | 277 | |
71e3aac0 AA |
278 | static ssize_t defrag_store(struct kobject *kobj, |
279 | struct kobj_attribute *attr, | |
280 | const char *buf, size_t count) | |
281 | { | |
f42f2552 | 282 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
283 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
284 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
285 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
286 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 287 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
288 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
289 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
290 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
291 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 292 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
293 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
294 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
295 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
296 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 297 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
298 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
299 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
300 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
301 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 302 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
303 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
304 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
305 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
306 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
307 | } else | |
308 | return -EINVAL; | |
309 | ||
310 | return count; | |
71e3aac0 AA |
311 | } |
312 | static struct kobj_attribute defrag_attr = | |
313 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
314 | ||
79da5407 | 315 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 316 | struct kobj_attribute *attr, char *buf) |
79da5407 | 317 | { |
b46e756f | 318 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 319 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
320 | } |
321 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
322 | struct kobj_attribute *attr, const char *buf, size_t count) | |
323 | { | |
b46e756f | 324 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
325 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
326 | } | |
327 | static struct kobj_attribute use_zero_page_attr = | |
328 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
49920d28 HD |
329 | |
330 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 331 | struct kobj_attribute *attr, char *buf) |
49920d28 | 332 | { |
ae7a927d | 333 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
334 | } |
335 | static struct kobj_attribute hpage_pmd_size_attr = | |
336 | __ATTR_RO(hpage_pmd_size); | |
337 | ||
71e3aac0 AA |
338 | static struct attribute *hugepage_attr[] = { |
339 | &enabled_attr.attr, | |
340 | &defrag_attr.attr, | |
79da5407 | 341 | &use_zero_page_attr.attr, |
49920d28 | 342 | &hpage_pmd_size_attr.attr, |
396bcc52 | 343 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 344 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
345 | #endif |
346 | NULL, | |
347 | }; | |
348 | ||
8aa95a21 | 349 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 350 | .attrs = hugepage_attr, |
ba76149f AA |
351 | }; |
352 | ||
569e5590 | 353 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 354 | { |
71e3aac0 AA |
355 | int err; |
356 | ||
569e5590 SL |
357 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
358 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 359 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 360 | return -ENOMEM; |
ba76149f AA |
361 | } |
362 | ||
569e5590 | 363 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 364 | if (err) { |
ae3a8c1c | 365 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 366 | goto delete_obj; |
ba76149f AA |
367 | } |
368 | ||
569e5590 | 369 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 370 | if (err) { |
ae3a8c1c | 371 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 372 | goto remove_hp_group; |
ba76149f | 373 | } |
569e5590 SL |
374 | |
375 | return 0; | |
376 | ||
377 | remove_hp_group: | |
378 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
379 | delete_obj: | |
380 | kobject_put(*hugepage_kobj); | |
381 | return err; | |
382 | } | |
383 | ||
384 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
385 | { | |
386 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
387 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
388 | kobject_put(hugepage_kobj); | |
389 | } | |
390 | #else | |
391 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
392 | { | |
393 | return 0; | |
394 | } | |
395 | ||
396 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
397 | { | |
398 | } | |
399 | #endif /* CONFIG_SYSFS */ | |
400 | ||
401 | static int __init hugepage_init(void) | |
402 | { | |
403 | int err; | |
404 | struct kobject *hugepage_kobj; | |
405 | ||
406 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
407 | /* |
408 | * Hardware doesn't support hugepages, hence disable | |
409 | * DAX PMD support. | |
410 | */ | |
411 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
412 | return -EINVAL; |
413 | } | |
414 | ||
ff20c2e0 KS |
415 | /* |
416 | * hugepages can't be allocated by the buddy allocator | |
417 | */ | |
418 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
419 | /* | |
420 | * we use page->mapping and page->index in second tail page | |
421 | * as list_head: assuming THP order >= 2 | |
422 | */ | |
423 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
424 | ||
569e5590 SL |
425 | err = hugepage_init_sysfs(&hugepage_kobj); |
426 | if (err) | |
65ebb64f | 427 | goto err_sysfs; |
ba76149f | 428 | |
b46e756f | 429 | err = khugepaged_init(); |
ba76149f | 430 | if (err) |
65ebb64f | 431 | goto err_slab; |
ba76149f | 432 | |
65ebb64f KS |
433 | err = register_shrinker(&huge_zero_page_shrinker); |
434 | if (err) | |
435 | goto err_hzp_shrinker; | |
9a982250 KS |
436 | err = register_shrinker(&deferred_split_shrinker); |
437 | if (err) | |
438 | goto err_split_shrinker; | |
97ae1749 | 439 | |
97562cd2 RR |
440 | /* |
441 | * By default disable transparent hugepages on smaller systems, | |
442 | * where the extra memory used could hurt more than TLB overhead | |
443 | * is likely to save. The admin can still enable it through /sys. | |
444 | */ | |
ca79b0c2 | 445 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 446 | transparent_hugepage_flags = 0; |
79553da2 KS |
447 | return 0; |
448 | } | |
97562cd2 | 449 | |
79553da2 | 450 | err = start_stop_khugepaged(); |
65ebb64f KS |
451 | if (err) |
452 | goto err_khugepaged; | |
ba76149f | 453 | |
569e5590 | 454 | return 0; |
65ebb64f | 455 | err_khugepaged: |
9a982250 KS |
456 | unregister_shrinker(&deferred_split_shrinker); |
457 | err_split_shrinker: | |
65ebb64f KS |
458 | unregister_shrinker(&huge_zero_page_shrinker); |
459 | err_hzp_shrinker: | |
b46e756f | 460 | khugepaged_destroy(); |
65ebb64f | 461 | err_slab: |
569e5590 | 462 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 463 | err_sysfs: |
ba76149f | 464 | return err; |
71e3aac0 | 465 | } |
a64fb3cd | 466 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
467 | |
468 | static int __init setup_transparent_hugepage(char *str) | |
469 | { | |
470 | int ret = 0; | |
471 | if (!str) | |
472 | goto out; | |
473 | if (!strcmp(str, "always")) { | |
474 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
475 | &transparent_hugepage_flags); | |
476 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
477 | &transparent_hugepage_flags); | |
478 | ret = 1; | |
479 | } else if (!strcmp(str, "madvise")) { | |
480 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
481 | &transparent_hugepage_flags); | |
482 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
483 | &transparent_hugepage_flags); | |
484 | ret = 1; | |
485 | } else if (!strcmp(str, "never")) { | |
486 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
487 | &transparent_hugepage_flags); | |
488 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
489 | &transparent_hugepage_flags); | |
490 | ret = 1; | |
491 | } | |
492 | out: | |
493 | if (!ret) | |
ae3a8c1c | 494 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
495 | return ret; |
496 | } | |
497 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
498 | ||
f55e1014 | 499 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 500 | { |
f55e1014 | 501 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
502 | pmd = pmd_mkwrite(pmd); |
503 | return pmd; | |
504 | } | |
505 | ||
87eaceb3 YS |
506 | #ifdef CONFIG_MEMCG |
507 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 508 | { |
bcfe06bf | 509 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 YS |
510 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); |
511 | ||
512 | if (memcg) | |
513 | return &memcg->deferred_split_queue; | |
514 | else | |
515 | return &pgdat->deferred_split_queue; | |
9a982250 | 516 | } |
87eaceb3 YS |
517 | #else |
518 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
519 | { | |
520 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
521 | ||
522 | return &pgdat->deferred_split_queue; | |
523 | } | |
524 | #endif | |
9a982250 KS |
525 | |
526 | void prep_transhuge_page(struct page *page) | |
527 | { | |
528 | /* | |
529 | * we use page->mapping and page->indexlru in second tail page | |
530 | * as list_head: assuming THP order >= 2 | |
531 | */ | |
9a982250 KS |
532 | |
533 | INIT_LIST_HEAD(page_deferred_list(page)); | |
534 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
535 | } | |
536 | ||
562beb72 | 537 | static inline bool is_transparent_hugepage(struct page *page) |
005ba37c SC |
538 | { |
539 | if (!PageCompound(page)) | |
fa1f68cc | 540 | return false; |
005ba37c SC |
541 | |
542 | page = compound_head(page); | |
543 | return is_huge_zero_page(page) || | |
544 | page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; | |
545 | } | |
005ba37c | 546 | |
97d3d0f9 KS |
547 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
548 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
549 | loff_t off, unsigned long flags, unsigned long size) |
550 | { | |
74d2fad1 TK |
551 | loff_t off_end = off + len; |
552 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 553 | unsigned long len_pad, ret; |
74d2fad1 TK |
554 | |
555 | if (off_end <= off_align || (off_end - off_align) < size) | |
556 | return 0; | |
557 | ||
558 | len_pad = len + size; | |
559 | if (len_pad < len || (off + len_pad) < off) | |
560 | return 0; | |
561 | ||
97d3d0f9 | 562 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 563 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
564 | |
565 | /* | |
566 | * The failure might be due to length padding. The caller will retry | |
567 | * without the padding. | |
568 | */ | |
569 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
570 | return 0; |
571 | ||
97d3d0f9 KS |
572 | /* |
573 | * Do not try to align to THP boundary if allocation at the address | |
574 | * hint succeeds. | |
575 | */ | |
576 | if (ret == addr) | |
577 | return addr; | |
578 | ||
579 | ret += (off - ret) & (size - 1); | |
580 | return ret; | |
74d2fad1 TK |
581 | } |
582 | ||
583 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
584 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
585 | { | |
97d3d0f9 | 586 | unsigned long ret; |
74d2fad1 TK |
587 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
588 | ||
97d3d0f9 KS |
589 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
590 | if (ret) | |
591 | return ret; | |
1854bc6e | 592 | |
74d2fad1 TK |
593 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
594 | } | |
595 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
596 | ||
2b740303 SJ |
597 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
598 | struct page *page, gfp_t gfp) | |
71e3aac0 | 599 | { |
82b0f8c3 | 600 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 601 | pgtable_t pgtable; |
82b0f8c3 | 602 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 603 | vm_fault_t ret = 0; |
71e3aac0 | 604 | |
309381fe | 605 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 606 | |
8f425e4e | 607 | if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { |
6b251fc9 AA |
608 | put_page(page); |
609 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 610 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
611 | return VM_FAULT_FALLBACK; |
612 | } | |
9d82c694 | 613 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 614 | |
4cf58924 | 615 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 616 | if (unlikely(!pgtable)) { |
6b31d595 MH |
617 | ret = VM_FAULT_OOM; |
618 | goto release; | |
00501b53 | 619 | } |
71e3aac0 | 620 | |
c79b57e4 | 621 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
622 | /* |
623 | * The memory barrier inside __SetPageUptodate makes sure that | |
624 | * clear_huge_page writes become visible before the set_pmd_at() | |
625 | * write. | |
626 | */ | |
71e3aac0 AA |
627 | __SetPageUptodate(page); |
628 | ||
82b0f8c3 JK |
629 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
630 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 631 | goto unlock_release; |
71e3aac0 AA |
632 | } else { |
633 | pmd_t entry; | |
6b251fc9 | 634 | |
6b31d595 MH |
635 | ret = check_stable_address_space(vma->vm_mm); |
636 | if (ret) | |
637 | goto unlock_release; | |
638 | ||
6b251fc9 AA |
639 | /* Deliver the page fault to userland */ |
640 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 641 | spin_unlock(vmf->ptl); |
6b251fc9 | 642 | put_page(page); |
bae473a4 | 643 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
644 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
645 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
646 | return ret; | |
6b251fc9 AA |
647 | } |
648 | ||
3122359a | 649 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 650 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
40f2bbf7 | 651 | page_add_new_anon_rmap(page, vma, haddr); |
b518154e | 652 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
653 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
654 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 655 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 656 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 657 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 658 | spin_unlock(vmf->ptl); |
6b251fc9 | 659 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 660 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
661 | } |
662 | ||
aa2e878e | 663 | return 0; |
6b31d595 MH |
664 | unlock_release: |
665 | spin_unlock(vmf->ptl); | |
666 | release: | |
667 | if (pgtable) | |
668 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
669 | put_page(page); |
670 | return ret; | |
671 | ||
71e3aac0 AA |
672 | } |
673 | ||
444eb2a4 | 674 | /* |
21440d7e DR |
675 | * always: directly stall for all thp allocations |
676 | * defer: wake kswapd and fail if not immediately available | |
677 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
678 | * fail if not immediately available | |
679 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
680 | * available | |
681 | * never: never stall for any thp allocation | |
444eb2a4 | 682 | */ |
164cc4fe | 683 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 684 | { |
164cc4fe | 685 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 686 | |
ac79f78d | 687 | /* Always do synchronous compaction */ |
a8282608 AA |
688 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
689 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
690 | |
691 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 692 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 693 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
694 | |
695 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 696 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
697 | return GFP_TRANSHUGE_LIGHT | |
698 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
699 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
700 | |
701 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 702 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
703 | return GFP_TRANSHUGE_LIGHT | |
704 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 705 | |
19deb769 | 706 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
707 | } |
708 | ||
c4088ebd | 709 | /* Caller must hold page table lock. */ |
2efeb8da | 710 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 711 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 712 | struct page *zero_page) |
fc9fe822 KS |
713 | { |
714 | pmd_t entry; | |
7c414164 | 715 | if (!pmd_none(*pmd)) |
2efeb8da | 716 | return; |
5918d10a | 717 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 718 | entry = pmd_mkhuge(entry); |
12c9d70b MW |
719 | if (pgtable) |
720 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
fc9fe822 | 721 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 722 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
723 | } |
724 | ||
2b740303 | 725 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 726 | { |
82b0f8c3 | 727 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 728 | gfp_t gfp; |
71e3aac0 | 729 | struct page *page; |
82b0f8c3 | 730 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 731 | |
43675e6f | 732 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 733 | return VM_FAULT_FALLBACK; |
128ec037 KS |
734 | if (unlikely(anon_vma_prepare(vma))) |
735 | return VM_FAULT_OOM; | |
6d50e60c | 736 | if (unlikely(khugepaged_enter(vma, vma->vm_flags))) |
128ec037 | 737 | return VM_FAULT_OOM; |
82b0f8c3 | 738 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 739 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
740 | transparent_hugepage_use_zero_page()) { |
741 | pgtable_t pgtable; | |
742 | struct page *zero_page; | |
2b740303 | 743 | vm_fault_t ret; |
4cf58924 | 744 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 745 | if (unlikely(!pgtable)) |
ba76149f | 746 | return VM_FAULT_OOM; |
6fcb52a5 | 747 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 748 | if (unlikely(!zero_page)) { |
bae473a4 | 749 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 750 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 751 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 752 | } |
82b0f8c3 | 753 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 754 | ret = 0; |
82b0f8c3 | 755 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
756 | ret = check_stable_address_space(vma->vm_mm); |
757 | if (ret) { | |
758 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 759 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 760 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 761 | spin_unlock(vmf->ptl); |
bfe8cc1d | 762 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 763 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
764 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
765 | } else { | |
bae473a4 | 766 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 767 | haddr, vmf->pmd, zero_page); |
fca40573 | 768 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 769 | spin_unlock(vmf->ptl); |
6b251fc9 | 770 | } |
bfe8cc1d | 771 | } else { |
82b0f8c3 | 772 | spin_unlock(vmf->ptl); |
bae473a4 | 773 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 774 | } |
6b251fc9 | 775 | return ret; |
71e3aac0 | 776 | } |
164cc4fe | 777 | gfp = vma_thp_gfp_mask(vma); |
19deb769 | 778 | page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER); |
128ec037 KS |
779 | if (unlikely(!page)) { |
780 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 781 | return VM_FAULT_FALLBACK; |
128ec037 | 782 | } |
9a982250 | 783 | prep_transhuge_page(page); |
82b0f8c3 | 784 | return __do_huge_pmd_anonymous_page(vmf, page, gfp); |
71e3aac0 AA |
785 | } |
786 | ||
ae18d6dc | 787 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
788 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
789 | pgtable_t pgtable) | |
5cad465d MW |
790 | { |
791 | struct mm_struct *mm = vma->vm_mm; | |
792 | pmd_t entry; | |
793 | spinlock_t *ptl; | |
794 | ||
795 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
796 | if (!pmd_none(*pmd)) { |
797 | if (write) { | |
798 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
799 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
800 | goto out_unlock; | |
801 | } | |
802 | entry = pmd_mkyoung(*pmd); | |
803 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
804 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
805 | update_mmu_cache_pmd(vma, addr, pmd); | |
806 | } | |
807 | ||
808 | goto out_unlock; | |
809 | } | |
810 | ||
f25748e3 DW |
811 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
812 | if (pfn_t_devmap(pfn)) | |
813 | entry = pmd_mkdevmap(entry); | |
01871e59 | 814 | if (write) { |
f55e1014 LT |
815 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
816 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 817 | } |
3b6521f5 OH |
818 | |
819 | if (pgtable) { | |
820 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 821 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 822 | pgtable = NULL; |
3b6521f5 OH |
823 | } |
824 | ||
01871e59 RZ |
825 | set_pmd_at(mm, addr, pmd, entry); |
826 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
827 | |
828 | out_unlock: | |
5cad465d | 829 | spin_unlock(ptl); |
c6f3c5ee AK |
830 | if (pgtable) |
831 | pte_free(mm, pgtable); | |
5cad465d MW |
832 | } |
833 | ||
9a9731b1 THV |
834 | /** |
835 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
836 | * @vmf: Structure describing the fault | |
837 | * @pfn: pfn to insert | |
838 | * @pgprot: page protection to use | |
839 | * @write: whether it's a write fault | |
840 | * | |
841 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
842 | * also consult the vmf_insert_mixed_prot() documentation when | |
843 | * @pgprot != @vmf->vma->vm_page_prot. | |
844 | * | |
845 | * Return: vm_fault_t value. | |
846 | */ | |
847 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
848 | pgprot_t pgprot, bool write) | |
5cad465d | 849 | { |
fce86ff5 DW |
850 | unsigned long addr = vmf->address & PMD_MASK; |
851 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 852 | pgtable_t pgtable = NULL; |
fce86ff5 | 853 | |
5cad465d MW |
854 | /* |
855 | * If we had pmd_special, we could avoid all these restrictions, | |
856 | * but we need to be consistent with PTEs and architectures that | |
857 | * can't support a 'special' bit. | |
858 | */ | |
e1fb4a08 DJ |
859 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
860 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
861 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
862 | (VM_PFNMAP|VM_MIXEDMAP)); | |
863 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
864 | |
865 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
866 | return VM_FAULT_SIGBUS; | |
308a047c | 867 | |
3b6521f5 | 868 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 869 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
870 | if (!pgtable) |
871 | return VM_FAULT_OOM; | |
872 | } | |
873 | ||
308a047c BP |
874 | track_pfn_insert(vma, &pgprot, pfn); |
875 | ||
fce86ff5 | 876 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 877 | return VM_FAULT_NOPAGE; |
5cad465d | 878 | } |
9a9731b1 | 879 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 880 | |
a00cc7d9 | 881 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 882 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 883 | { |
f55e1014 | 884 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
885 | pud = pud_mkwrite(pud); |
886 | return pud; | |
887 | } | |
888 | ||
889 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
890 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
891 | { | |
892 | struct mm_struct *mm = vma->vm_mm; | |
893 | pud_t entry; | |
894 | spinlock_t *ptl; | |
895 | ||
896 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
897 | if (!pud_none(*pud)) { |
898 | if (write) { | |
899 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
900 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
901 | goto out_unlock; | |
902 | } | |
903 | entry = pud_mkyoung(*pud); | |
904 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
905 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
906 | update_mmu_cache_pud(vma, addr, pud); | |
907 | } | |
908 | goto out_unlock; | |
909 | } | |
910 | ||
a00cc7d9 MW |
911 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
912 | if (pfn_t_devmap(pfn)) | |
913 | entry = pud_mkdevmap(entry); | |
914 | if (write) { | |
f55e1014 LT |
915 | entry = pud_mkyoung(pud_mkdirty(entry)); |
916 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
917 | } |
918 | set_pud_at(mm, addr, pud, entry); | |
919 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
920 | |
921 | out_unlock: | |
a00cc7d9 MW |
922 | spin_unlock(ptl); |
923 | } | |
924 | ||
9a9731b1 THV |
925 | /** |
926 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
927 | * @vmf: Structure describing the fault | |
928 | * @pfn: pfn to insert | |
929 | * @pgprot: page protection to use | |
930 | * @write: whether it's a write fault | |
931 | * | |
932 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
933 | * also consult the vmf_insert_mixed_prot() documentation when | |
934 | * @pgprot != @vmf->vma->vm_page_prot. | |
935 | * | |
936 | * Return: vm_fault_t value. | |
937 | */ | |
938 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
939 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 940 | { |
fce86ff5 DW |
941 | unsigned long addr = vmf->address & PUD_MASK; |
942 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 943 | |
a00cc7d9 MW |
944 | /* |
945 | * If we had pud_special, we could avoid all these restrictions, | |
946 | * but we need to be consistent with PTEs and architectures that | |
947 | * can't support a 'special' bit. | |
948 | */ | |
62ec0d8c DJ |
949 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
950 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
951 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
952 | (VM_PFNMAP|VM_MIXEDMAP)); | |
953 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
954 | |
955 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
956 | return VM_FAULT_SIGBUS; | |
957 | ||
958 | track_pfn_insert(vma, &pgprot, pfn); | |
959 | ||
fce86ff5 | 960 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
961 | return VM_FAULT_NOPAGE; |
962 | } | |
9a9731b1 | 963 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
964 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
965 | ||
3565fce3 | 966 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a8f97366 | 967 | pmd_t *pmd, int flags) |
3565fce3 DW |
968 | { |
969 | pmd_t _pmd; | |
970 | ||
a8f97366 KS |
971 | _pmd = pmd_mkyoung(*pmd); |
972 | if (flags & FOLL_WRITE) | |
973 | _pmd = pmd_mkdirty(_pmd); | |
3565fce3 | 974 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a8f97366 | 975 | pmd, _pmd, flags & FOLL_WRITE)) |
3565fce3 DW |
976 | update_mmu_cache_pmd(vma, addr, pmd); |
977 | } | |
978 | ||
979 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 980 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
981 | { |
982 | unsigned long pfn = pmd_pfn(*pmd); | |
983 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 DW |
984 | struct page *page; |
985 | ||
986 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
987 | ||
8310d48b KF |
988 | /* |
989 | * When we COW a devmap PMD entry, we split it into PTEs, so we should | |
990 | * not be in this function with `flags & FOLL_COW` set. | |
991 | */ | |
992 | WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set"); | |
993 | ||
3faa52c0 JH |
994 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
995 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
996 | (FOLL_PIN | FOLL_GET))) | |
997 | return NULL; | |
998 | ||
f6f37321 | 999 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
1000 | return NULL; |
1001 | ||
1002 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
1003 | /* pass */; | |
1004 | else | |
1005 | return NULL; | |
1006 | ||
1007 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1008 | touch_pmd(vma, addr, pmd, flags); |
3565fce3 DW |
1009 | |
1010 | /* | |
1011 | * device mapped pages can only be returned if the | |
1012 | * caller will manage the page reference count. | |
1013 | */ | |
3faa52c0 | 1014 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1015 | return ERR_PTR(-EEXIST); |
1016 | ||
1017 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1018 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1019 | if (!*pgmap) | |
3565fce3 DW |
1020 | return ERR_PTR(-EFAULT); |
1021 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1022 | if (!try_grab_page(page, flags)) |
1023 | page = ERR_PTR(-ENOMEM); | |
3565fce3 DW |
1024 | |
1025 | return page; | |
1026 | } | |
1027 | ||
71e3aac0 AA |
1028 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1029 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
8f34f1ea | 1030 | struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) |
71e3aac0 | 1031 | { |
c4088ebd | 1032 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1033 | struct page *src_page; |
1034 | pmd_t pmd; | |
12c9d70b | 1035 | pgtable_t pgtable = NULL; |
628d47ce | 1036 | int ret = -ENOMEM; |
71e3aac0 | 1037 | |
628d47ce | 1038 | /* Skip if can be re-fill on fault */ |
8f34f1ea | 1039 | if (!vma_is_anonymous(dst_vma)) |
628d47ce KS |
1040 | return 0; |
1041 | ||
4cf58924 | 1042 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1043 | if (unlikely(!pgtable)) |
1044 | goto out; | |
71e3aac0 | 1045 | |
c4088ebd KS |
1046 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1047 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1048 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1049 | |
1050 | ret = -EAGAIN; | |
1051 | pmd = *src_pmd; | |
84c3fc4e ZY |
1052 | |
1053 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1054 | if (unlikely(is_swap_pmd(pmd))) { | |
1055 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1056 | ||
1057 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
6c287605 | 1058 | if (!is_readable_migration_entry(entry)) { |
4dd845b5 AP |
1059 | entry = make_readable_migration_entry( |
1060 | swp_offset(entry)); | |
84c3fc4e | 1061 | pmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1062 | if (pmd_swp_soft_dirty(*src_pmd)) |
1063 | pmd = pmd_swp_mksoft_dirty(pmd); | |
8f34f1ea PX |
1064 | if (pmd_swp_uffd_wp(*src_pmd)) |
1065 | pmd = pmd_swp_mkuffd_wp(pmd); | |
84c3fc4e ZY |
1066 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1067 | } | |
dd8a67f9 | 1068 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1069 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1070 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
8f34f1ea PX |
1071 | if (!userfaultfd_wp(dst_vma)) |
1072 | pmd = pmd_swp_clear_uffd_wp(pmd); | |
84c3fc4e ZY |
1073 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1074 | ret = 0; | |
1075 | goto out_unlock; | |
1076 | } | |
1077 | #endif | |
1078 | ||
628d47ce | 1079 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1080 | pte_free(dst_mm, pgtable); |
1081 | goto out_unlock; | |
1082 | } | |
fc9fe822 | 1083 | /* |
c4088ebd | 1084 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1085 | * under splitting since we don't split the page itself, only pmd to |
1086 | * a page table. | |
1087 | */ | |
1088 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 KS |
1089 | /* |
1090 | * get_huge_zero_page() will never allocate a new page here, | |
1091 | * since we already have a zero page to copy. It just takes a | |
1092 | * reference. | |
1093 | */ | |
5fc7a5f6 PX |
1094 | mm_get_huge_zero_page(dst_mm); |
1095 | goto out_zero_page; | |
fc9fe822 | 1096 | } |
de466bd6 | 1097 | |
628d47ce KS |
1098 | src_page = pmd_page(pmd); |
1099 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e | 1100 | |
fb3d824d DH |
1101 | get_page(src_page); |
1102 | if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { | |
1103 | /* Page maybe pinned: split and retry the fault on PTEs. */ | |
1104 | put_page(src_page); | |
d042035e PX |
1105 | pte_free(dst_mm, pgtable); |
1106 | spin_unlock(src_ptl); | |
1107 | spin_unlock(dst_ptl); | |
8f34f1ea | 1108 | __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); |
d042035e PX |
1109 | return -EAGAIN; |
1110 | } | |
628d47ce | 1111 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
5fc7a5f6 | 1112 | out_zero_page: |
c4812909 | 1113 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1114 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 1115 | pmdp_set_wrprotect(src_mm, addr, src_pmd); |
8f34f1ea PX |
1116 | if (!userfaultfd_wp(dst_vma)) |
1117 | pmd = pmd_clear_uffd_wp(pmd); | |
71e3aac0 AA |
1118 | pmd = pmd_mkold(pmd_wrprotect(pmd)); |
1119 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1120 | |
1121 | ret = 0; | |
1122 | out_unlock: | |
c4088ebd KS |
1123 | spin_unlock(src_ptl); |
1124 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1125 | out: |
1126 | return ret; | |
1127 | } | |
1128 | ||
a00cc7d9 MW |
1129 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1130 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
a8f97366 | 1131 | pud_t *pud, int flags) |
a00cc7d9 MW |
1132 | { |
1133 | pud_t _pud; | |
1134 | ||
a8f97366 KS |
1135 | _pud = pud_mkyoung(*pud); |
1136 | if (flags & FOLL_WRITE) | |
1137 | _pud = pud_mkdirty(_pud); | |
a00cc7d9 | 1138 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
a8f97366 | 1139 | pud, _pud, flags & FOLL_WRITE)) |
a00cc7d9 MW |
1140 | update_mmu_cache_pud(vma, addr, pud); |
1141 | } | |
1142 | ||
1143 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1144 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1145 | { |
1146 | unsigned long pfn = pud_pfn(*pud); | |
1147 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 MW |
1148 | struct page *page; |
1149 | ||
1150 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1151 | ||
f6f37321 | 1152 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1153 | return NULL; |
1154 | ||
3faa52c0 JH |
1155 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1156 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1157 | (FOLL_PIN | FOLL_GET))) | |
1158 | return NULL; | |
1159 | ||
a00cc7d9 MW |
1160 | if (pud_present(*pud) && pud_devmap(*pud)) |
1161 | /* pass */; | |
1162 | else | |
1163 | return NULL; | |
1164 | ||
1165 | if (flags & FOLL_TOUCH) | |
a8f97366 | 1166 | touch_pud(vma, addr, pud, flags); |
a00cc7d9 MW |
1167 | |
1168 | /* | |
1169 | * device mapped pages can only be returned if the | |
1170 | * caller will manage the page reference count. | |
3faa52c0 JH |
1171 | * |
1172 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1173 | */ |
3faa52c0 | 1174 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1175 | return ERR_PTR(-EEXIST); |
1176 | ||
1177 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1178 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1179 | if (!*pgmap) | |
a00cc7d9 MW |
1180 | return ERR_PTR(-EFAULT); |
1181 | page = pfn_to_page(pfn); | |
3faa52c0 JH |
1182 | if (!try_grab_page(page, flags)) |
1183 | page = ERR_PTR(-ENOMEM); | |
a00cc7d9 MW |
1184 | |
1185 | return page; | |
1186 | } | |
1187 | ||
1188 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1189 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1190 | struct vm_area_struct *vma) | |
1191 | { | |
1192 | spinlock_t *dst_ptl, *src_ptl; | |
1193 | pud_t pud; | |
1194 | int ret; | |
1195 | ||
1196 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1197 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1198 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1199 | ||
1200 | ret = -EAGAIN; | |
1201 | pud = *src_pud; | |
1202 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1203 | goto out_unlock; | |
1204 | ||
1205 | /* | |
1206 | * When page table lock is held, the huge zero pud should not be | |
1207 | * under splitting since we don't split the page itself, only pud to | |
1208 | * a page table. | |
1209 | */ | |
1210 | if (is_huge_zero_pud(pud)) { | |
1211 | /* No huge zero pud yet */ | |
1212 | } | |
1213 | ||
fb3d824d DH |
1214 | /* |
1215 | * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() | |
1216 | * and split if duplicating fails. | |
1217 | */ | |
a00cc7d9 MW |
1218 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1219 | pud = pud_mkold(pud_wrprotect(pud)); | |
1220 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1221 | ||
1222 | ret = 0; | |
1223 | out_unlock: | |
1224 | spin_unlock(src_ptl); | |
1225 | spin_unlock(dst_ptl); | |
1226 | return ret; | |
1227 | } | |
1228 | ||
1229 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1230 | { | |
1231 | pud_t entry; | |
1232 | unsigned long haddr; | |
1233 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
1234 | ||
1235 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1236 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1237 | goto unlock; | |
1238 | ||
1239 | entry = pud_mkyoung(orig_pud); | |
1240 | if (write) | |
1241 | entry = pud_mkdirty(entry); | |
1242 | haddr = vmf->address & HPAGE_PUD_MASK; | |
1243 | if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write)) | |
1244 | update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud); | |
1245 | ||
1246 | unlock: | |
1247 | spin_unlock(vmf->ptl); | |
1248 | } | |
1249 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1250 | ||
5db4f15c | 1251 | void huge_pmd_set_accessed(struct vm_fault *vmf) |
a1dd450b WD |
1252 | { |
1253 | pmd_t entry; | |
1254 | unsigned long haddr; | |
20f664aa | 1255 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
5db4f15c | 1256 | pmd_t orig_pmd = vmf->orig_pmd; |
a1dd450b | 1257 | |
82b0f8c3 JK |
1258 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1259 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) | |
a1dd450b WD |
1260 | goto unlock; |
1261 | ||
1262 | entry = pmd_mkyoung(orig_pmd); | |
20f664aa MK |
1263 | if (write) |
1264 | entry = pmd_mkdirty(entry); | |
82b0f8c3 | 1265 | haddr = vmf->address & HPAGE_PMD_MASK; |
20f664aa | 1266 | if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write)) |
82b0f8c3 | 1267 | update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd); |
a1dd450b WD |
1268 | |
1269 | unlock: | |
82b0f8c3 | 1270 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1271 | } |
1272 | ||
5db4f15c | 1273 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) |
71e3aac0 | 1274 | { |
c89357e2 | 1275 | const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; |
82b0f8c3 | 1276 | struct vm_area_struct *vma = vmf->vma; |
3917c802 | 1277 | struct page *page; |
82b0f8c3 | 1278 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
5db4f15c | 1279 | pmd_t orig_pmd = vmf->orig_pmd; |
71e3aac0 | 1280 | |
82b0f8c3 | 1281 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1282 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1283 | |
c89357e2 DH |
1284 | VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE)); |
1285 | VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE)); | |
1286 | ||
93b4796d | 1287 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1288 | goto fallback; |
1289 | ||
82b0f8c3 | 1290 | spin_lock(vmf->ptl); |
3917c802 KS |
1291 | |
1292 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1293 | spin_unlock(vmf->ptl); | |
1294 | return 0; | |
1295 | } | |
71e3aac0 AA |
1296 | |
1297 | page = pmd_page(orig_pmd); | |
f6004e73 | 1298 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 | 1299 | |
6c287605 DH |
1300 | /* Early check when only holding the PT lock. */ |
1301 | if (PageAnonExclusive(page)) | |
1302 | goto reuse; | |
1303 | ||
ba3c4ce6 HY |
1304 | if (!trylock_page(page)) { |
1305 | get_page(page); | |
1306 | spin_unlock(vmf->ptl); | |
1307 | lock_page(page); | |
1308 | spin_lock(vmf->ptl); | |
1309 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1310 | spin_unlock(vmf->ptl); |
ba3c4ce6 HY |
1311 | unlock_page(page); |
1312 | put_page(page); | |
3917c802 | 1313 | return 0; |
ba3c4ce6 HY |
1314 | } |
1315 | put_page(page); | |
1316 | } | |
3917c802 | 1317 | |
6c287605 DH |
1318 | /* Recheck after temporarily dropping the PT lock. */ |
1319 | if (PageAnonExclusive(page)) { | |
1320 | unlock_page(page); | |
1321 | goto reuse; | |
1322 | } | |
1323 | ||
3917c802 | 1324 | /* |
c89357e2 | 1325 | * See do_wp_page(): we can only reuse the page exclusively if there are |
3bff7e3f DH |
1326 | * no additional references. Note that we always drain the LRU |
1327 | * pagevecs immediately after adding a THP. | |
3917c802 | 1328 | */ |
3bff7e3f DH |
1329 | if (page_count(page) > 1 + PageSwapCache(page) * thp_nr_pages(page)) |
1330 | goto unlock_fallback; | |
1331 | if (PageSwapCache(page)) | |
1332 | try_to_free_swap(page); | |
1333 | if (page_count(page) == 1) { | |
71e3aac0 | 1334 | pmd_t entry; |
6c54dc6c DH |
1335 | |
1336 | page_move_anon_rmap(page, vma); | |
6c287605 DH |
1337 | unlock_page(page); |
1338 | reuse: | |
c89357e2 DH |
1339 | if (unlikely(unshare)) { |
1340 | spin_unlock(vmf->ptl); | |
1341 | return 0; | |
1342 | } | |
71e3aac0 | 1343 | entry = pmd_mkyoung(orig_pmd); |
f55e1014 | 1344 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1345 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1346 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 1347 | spin_unlock(vmf->ptl); |
3917c802 | 1348 | return VM_FAULT_WRITE; |
71e3aac0 | 1349 | } |
3917c802 | 1350 | |
3bff7e3f | 1351 | unlock_fallback: |
3917c802 | 1352 | unlock_page(page); |
82b0f8c3 | 1353 | spin_unlock(vmf->ptl); |
3917c802 KS |
1354 | fallback: |
1355 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1356 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1357 | } |
1358 | ||
8310d48b | 1359 | /* |
a308c71b PX |
1360 | * FOLL_FORCE can write to even unwritable pmd's, but only |
1361 | * after we've gone through a COW cycle and they are dirty. | |
8310d48b KF |
1362 | */ |
1363 | static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) | |
1364 | { | |
a308c71b PX |
1365 | return pmd_write(pmd) || |
1366 | ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); | |
8310d48b KF |
1367 | } |
1368 | ||
b676b293 | 1369 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1370 | unsigned long addr, |
1371 | pmd_t *pmd, | |
1372 | unsigned int flags) | |
1373 | { | |
b676b293 | 1374 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1375 | struct page *page = NULL; |
1376 | ||
c4088ebd | 1377 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1378 | |
8310d48b | 1379 | if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) |
71e3aac0 AA |
1380 | goto out; |
1381 | ||
85facf25 KS |
1382 | /* Avoid dumping huge zero page */ |
1383 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1384 | return ERR_PTR(-EFAULT); | |
1385 | ||
2b4847e7 | 1386 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
8a0516ed | 1387 | if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) |
2b4847e7 MG |
1388 | goto out; |
1389 | ||
71e3aac0 | 1390 | page = pmd_page(*pmd); |
ca120cf6 | 1391 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); |
3faa52c0 | 1392 | |
a7f22660 DH |
1393 | if (!pmd_write(*pmd) && gup_must_unshare(flags, page)) |
1394 | return ERR_PTR(-EMLINK); | |
1395 | ||
b6a2619c DH |
1396 | VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && |
1397 | !PageAnonExclusive(page), page); | |
1398 | ||
3faa52c0 JH |
1399 | if (!try_grab_page(page, flags)) |
1400 | return ERR_PTR(-ENOMEM); | |
1401 | ||
3565fce3 | 1402 | if (flags & FOLL_TOUCH) |
a8f97366 | 1403 | touch_pmd(vma, addr, pmd, flags); |
3faa52c0 | 1404 | |
71e3aac0 | 1405 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1406 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 AA |
1407 | |
1408 | out: | |
1409 | return page; | |
1410 | } | |
1411 | ||
d10e63f2 | 1412 | /* NUMA hinting page fault entry point for trans huge pmds */ |
5db4f15c | 1413 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) |
d10e63f2 | 1414 | { |
82b0f8c3 | 1415 | struct vm_area_struct *vma = vmf->vma; |
c5b5a3dd YS |
1416 | pmd_t oldpmd = vmf->orig_pmd; |
1417 | pmd_t pmd; | |
b32967ff | 1418 | struct page *page; |
82b0f8c3 | 1419 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
c5b5a3dd | 1420 | int page_nid = NUMA_NO_NODE; |
90572890 | 1421 | int target_nid, last_cpupid = -1; |
8191acbd | 1422 | bool migrated = false; |
c5b5a3dd | 1423 | bool was_writable = pmd_savedwrite(oldpmd); |
6688cc05 | 1424 | int flags = 0; |
d10e63f2 | 1425 | |
82b0f8c3 | 1426 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
c5b5a3dd | 1427 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { |
82b0f8c3 | 1428 | spin_unlock(vmf->ptl); |
de466bd6 MG |
1429 | goto out; |
1430 | } | |
1431 | ||
c5b5a3dd YS |
1432 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); |
1433 | page = vm_normal_page_pmd(vma, haddr, pmd); | |
1434 | if (!page) | |
1435 | goto out_map; | |
1436 | ||
1437 | /* See similar comment in do_numa_page for explanation */ | |
1438 | if (!was_writable) | |
1439 | flags |= TNF_NO_GROUP; | |
1440 | ||
1441 | page_nid = page_to_nid(page); | |
1442 | last_cpupid = page_cpupid_last(page); | |
1443 | target_nid = numa_migrate_prep(page, vma, haddr, page_nid, | |
1444 | &flags); | |
1445 | ||
1446 | if (target_nid == NUMA_NO_NODE) { | |
1447 | put_page(page); | |
1448 | goto out_map; | |
1449 | } | |
1450 | ||
82b0f8c3 | 1451 | spin_unlock(vmf->ptl); |
8b1b436d | 1452 | |
c5b5a3dd | 1453 | migrated = migrate_misplaced_page(page, vma, target_nid); |
6688cc05 PZ |
1454 | if (migrated) { |
1455 | flags |= TNF_MIGRATED; | |
8191acbd | 1456 | page_nid = target_nid; |
c5b5a3dd | 1457 | } else { |
074c2381 | 1458 | flags |= TNF_MIGRATE_FAIL; |
c5b5a3dd YS |
1459 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1460 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { | |
1461 | spin_unlock(vmf->ptl); | |
1462 | goto out; | |
1463 | } | |
1464 | goto out_map; | |
1465 | } | |
b8916634 MG |
1466 | |
1467 | out: | |
98fa15f3 | 1468 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1469 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1470 | flags); |
8191acbd | 1471 | |
d10e63f2 | 1472 | return 0; |
c5b5a3dd YS |
1473 | |
1474 | out_map: | |
1475 | /* Restore the PMD */ | |
1476 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); | |
1477 | pmd = pmd_mkyoung(pmd); | |
1478 | if (was_writable) | |
1479 | pmd = pmd_mkwrite(pmd); | |
1480 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); | |
1481 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
1482 | spin_unlock(vmf->ptl); | |
1483 | goto out; | |
d10e63f2 MG |
1484 | } |
1485 | ||
319904ad HY |
1486 | /* |
1487 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1488 | * Otherwise, return false. | |
1489 | */ | |
1490 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1491 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1492 | { |
1493 | spinlock_t *ptl; | |
1494 | pmd_t orig_pmd; | |
1495 | struct page *page; | |
1496 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1497 | bool ret = false; |
b8d3c4c3 | 1498 | |
ed6a7935 | 1499 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1500 | |
b6ec57f4 KS |
1501 | ptl = pmd_trans_huge_lock(pmd, vma); |
1502 | if (!ptl) | |
25eedabe | 1503 | goto out_unlocked; |
b8d3c4c3 MK |
1504 | |
1505 | orig_pmd = *pmd; | |
319904ad | 1506 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1507 | goto out; |
b8d3c4c3 | 1508 | |
84c3fc4e ZY |
1509 | if (unlikely(!pmd_present(orig_pmd))) { |
1510 | VM_BUG_ON(thp_migration_supported() && | |
1511 | !is_pmd_migration_entry(orig_pmd)); | |
1512 | goto out; | |
1513 | } | |
1514 | ||
b8d3c4c3 MK |
1515 | page = pmd_page(orig_pmd); |
1516 | /* | |
1517 | * If other processes are mapping this page, we couldn't discard | |
1518 | * the page unless they all do MADV_FREE so let's skip the page. | |
1519 | */ | |
babbbdd0 | 1520 | if (total_mapcount(page) != 1) |
b8d3c4c3 MK |
1521 | goto out; |
1522 | ||
1523 | if (!trylock_page(page)) | |
1524 | goto out; | |
1525 | ||
1526 | /* | |
1527 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1528 | * will deactivate only them. | |
1529 | */ | |
1530 | if (next - addr != HPAGE_PMD_SIZE) { | |
1531 | get_page(page); | |
1532 | spin_unlock(ptl); | |
9818b8cd | 1533 | split_huge_page(page); |
b8d3c4c3 | 1534 | unlock_page(page); |
bbf29ffc | 1535 | put_page(page); |
b8d3c4c3 MK |
1536 | goto out_unlocked; |
1537 | } | |
1538 | ||
1539 | if (PageDirty(page)) | |
1540 | ClearPageDirty(page); | |
1541 | unlock_page(page); | |
1542 | ||
b8d3c4c3 | 1543 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1544 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1545 | orig_pmd = pmd_mkold(orig_pmd); |
1546 | orig_pmd = pmd_mkclean(orig_pmd); | |
1547 | ||
1548 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1549 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1550 | } | |
802a3a92 SL |
1551 | |
1552 | mark_page_lazyfree(page); | |
319904ad | 1553 | ret = true; |
b8d3c4c3 MK |
1554 | out: |
1555 | spin_unlock(ptl); | |
1556 | out_unlocked: | |
1557 | return ret; | |
1558 | } | |
1559 | ||
953c66c2 AK |
1560 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1561 | { | |
1562 | pgtable_t pgtable; | |
1563 | ||
1564 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1565 | pte_free(mm, pgtable); | |
c4812909 | 1566 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1567 | } |
1568 | ||
71e3aac0 | 1569 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1570 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1571 | { |
da146769 | 1572 | pmd_t orig_pmd; |
bf929152 | 1573 | spinlock_t *ptl; |
71e3aac0 | 1574 | |
ed6a7935 | 1575 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1576 | |
b6ec57f4 KS |
1577 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1578 | if (!ptl) | |
da146769 KS |
1579 | return 0; |
1580 | /* | |
1581 | * For architectures like ppc64 we look at deposited pgtable | |
1582 | * when calling pmdp_huge_get_and_clear. So do the | |
1583 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1584 | * operations. | |
1585 | */ | |
93a98695 AK |
1586 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1587 | tlb->fullmm); | |
da146769 | 1588 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1589 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1590 | if (arch_needs_pgtable_deposit()) |
1591 | zap_deposited_table(tlb->mm, pmd); | |
da146769 | 1592 | spin_unlock(ptl); |
da146769 | 1593 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1594 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1595 | spin_unlock(ptl); |
da146769 | 1596 | } else { |
616b8371 ZY |
1597 | struct page *page = NULL; |
1598 | int flush_needed = 1; | |
1599 | ||
1600 | if (pmd_present(orig_pmd)) { | |
1601 | page = pmd_page(orig_pmd); | |
cea86fe2 | 1602 | page_remove_rmap(page, vma, true); |
616b8371 ZY |
1603 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
1604 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1605 | } else if (thp_migration_supported()) { | |
1606 | swp_entry_t entry; | |
1607 | ||
1608 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1609 | entry = pmd_to_swp_entry(orig_pmd); | |
af5cdaf8 | 1610 | page = pfn_swap_entry_to_page(entry); |
616b8371 ZY |
1611 | flush_needed = 0; |
1612 | } else | |
1613 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1614 | ||
b5072380 | 1615 | if (PageAnon(page)) { |
c14a6eb4 | 1616 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1617 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1618 | } else { | |
953c66c2 AK |
1619 | if (arch_needs_pgtable_deposit()) |
1620 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1621 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1622 | } |
616b8371 | 1623 | |
da146769 | 1624 | spin_unlock(ptl); |
616b8371 ZY |
1625 | if (flush_needed) |
1626 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1627 | } |
da146769 | 1628 | return 1; |
71e3aac0 AA |
1629 | } |
1630 | ||
1dd38b6c AK |
1631 | #ifndef pmd_move_must_withdraw |
1632 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1633 | spinlock_t *old_pmd_ptl, | |
1634 | struct vm_area_struct *vma) | |
1635 | { | |
1636 | /* | |
1637 | * With split pmd lock we also need to move preallocated | |
1638 | * PTE page table if new_pmd is on different PMD page table. | |
1639 | * | |
1640 | * We also don't deposit and withdraw tables for file pages. | |
1641 | */ | |
1642 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1643 | } | |
1644 | #endif | |
1645 | ||
ab6e3d09 NH |
1646 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1647 | { | |
1648 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1649 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1650 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1651 | else if (pmd_present(pmd)) | |
1652 | pmd = pmd_mksoft_dirty(pmd); | |
1653 | #endif | |
1654 | return pmd; | |
1655 | } | |
1656 | ||
bf8616d5 | 1657 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1658 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1659 | { |
bf929152 | 1660 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1661 | pmd_t pmd; |
37a1c49a | 1662 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1663 | bool force_flush = false; |
37a1c49a | 1664 | |
37a1c49a AA |
1665 | /* |
1666 | * The destination pmd shouldn't be established, free_pgtables() | |
1667 | * should have release it. | |
1668 | */ | |
1669 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1670 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1671 | return false; |
37a1c49a AA |
1672 | } |
1673 | ||
bf929152 KS |
1674 | /* |
1675 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1676 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1677 | */ |
b6ec57f4 KS |
1678 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1679 | if (old_ptl) { | |
bf929152 KS |
1680 | new_ptl = pmd_lockptr(mm, new_pmd); |
1681 | if (new_ptl != old_ptl) | |
1682 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1683 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1684 | if (pmd_present(pmd)) |
a2ce2666 | 1685 | force_flush = true; |
025c5b24 | 1686 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1687 | |
1dd38b6c | 1688 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1689 | pgtable_t pgtable; |
3592806c KS |
1690 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1691 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1692 | } |
ab6e3d09 NH |
1693 | pmd = move_soft_dirty_pmd(pmd); |
1694 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 AL |
1695 | if (force_flush) |
1696 | flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE); | |
eb66ae03 LT |
1697 | if (new_ptl != old_ptl) |
1698 | spin_unlock(new_ptl); | |
bf929152 | 1699 | spin_unlock(old_ptl); |
4b471e88 | 1700 | return true; |
37a1c49a | 1701 | } |
4b471e88 | 1702 | return false; |
37a1c49a AA |
1703 | } |
1704 | ||
f123d74a MG |
1705 | /* |
1706 | * Returns | |
1707 | * - 0 if PMD could not be locked | |
f0953a1b | 1708 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
e346e668 | 1709 | * or if prot_numa but THP migration is not supported |
f0953a1b | 1710 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary |
f123d74a | 1711 | */ |
4a18419f NA |
1712 | int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
1713 | pmd_t *pmd, unsigned long addr, pgprot_t newprot, | |
1714 | unsigned long cp_flags) | |
cd7548ab JW |
1715 | { |
1716 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1717 | spinlock_t *ptl; |
c9fe6656 | 1718 | pmd_t oldpmd, entry; |
0a85e51d KS |
1719 | bool preserve_write; |
1720 | int ret; | |
58705444 | 1721 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1722 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1723 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
cd7548ab | 1724 | |
4a18419f NA |
1725 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
1726 | ||
e346e668 YS |
1727 | if (prot_numa && !thp_migration_supported()) |
1728 | return 1; | |
1729 | ||
b6ec57f4 | 1730 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1731 | if (!ptl) |
1732 | return 0; | |
e944fd67 | 1733 | |
0a85e51d KS |
1734 | preserve_write = prot_numa && pmd_write(*pmd); |
1735 | ret = 1; | |
e944fd67 | 1736 | |
84c3fc4e ZY |
1737 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1738 | if (is_swap_pmd(*pmd)) { | |
1739 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
6c287605 | 1740 | struct page *page = pfn_swap_entry_to_page(entry); |
84c3fc4e ZY |
1741 | |
1742 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
4dd845b5 | 1743 | if (is_writable_migration_entry(entry)) { |
84c3fc4e ZY |
1744 | pmd_t newpmd; |
1745 | /* | |
1746 | * A protection check is difficult so | |
1747 | * just be safe and disable write | |
1748 | */ | |
6c287605 DH |
1749 | if (PageAnon(page)) |
1750 | entry = make_readable_exclusive_migration_entry(swp_offset(entry)); | |
1751 | else | |
1752 | entry = make_readable_migration_entry(swp_offset(entry)); | |
84c3fc4e | 1753 | newpmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1754 | if (pmd_swp_soft_dirty(*pmd)) |
1755 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
8f34f1ea PX |
1756 | if (pmd_swp_uffd_wp(*pmd)) |
1757 | newpmd = pmd_swp_mkuffd_wp(newpmd); | |
84c3fc4e ZY |
1758 | set_pmd_at(mm, addr, pmd, newpmd); |
1759 | } | |
1760 | goto unlock; | |
1761 | } | |
1762 | #endif | |
1763 | ||
a1a3a2fc HY |
1764 | if (prot_numa) { |
1765 | struct page *page; | |
1766 | /* | |
1767 | * Avoid trapping faults against the zero page. The read-only | |
1768 | * data is likely to be read-cached on the local CPU and | |
1769 | * local/remote hits to the zero page are not interesting. | |
1770 | */ | |
1771 | if (is_huge_zero_pmd(*pmd)) | |
1772 | goto unlock; | |
025c5b24 | 1773 | |
a1a3a2fc HY |
1774 | if (pmd_protnone(*pmd)) |
1775 | goto unlock; | |
0a85e51d | 1776 | |
a1a3a2fc HY |
1777 | page = pmd_page(*pmd); |
1778 | /* | |
1779 | * Skip scanning top tier node if normal numa | |
1780 | * balancing is disabled | |
1781 | */ | |
1782 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
1783 | node_is_toptier(page_to_nid(page))) | |
1784 | goto unlock; | |
1785 | } | |
ced10803 | 1786 | /* |
3e4e28c5 | 1787 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1788 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1789 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1790 | * |
1791 | * CPU0: CPU1: | |
1792 | * change_huge_pmd(prot_numa=1) | |
1793 | * pmdp_huge_get_and_clear_notify() | |
1794 | * madvise_dontneed() | |
1795 | * zap_pmd_range() | |
1796 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1797 | * // skip the pmd | |
1798 | * set_pmd_at(); | |
1799 | * // pmd is re-established | |
1800 | * | |
1801 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1802 | * which may break userspace. | |
1803 | * | |
4f831457 | 1804 | * pmdp_invalidate_ad() is required to make sure we don't miss |
ced10803 KS |
1805 | * dirty/young flags set by hardware. |
1806 | */ | |
4f831457 | 1807 | oldpmd = pmdp_invalidate_ad(vma, addr, pmd); |
ced10803 | 1808 | |
c9fe6656 | 1809 | entry = pmd_modify(oldpmd, newprot); |
0a85e51d KS |
1810 | if (preserve_write) |
1811 | entry = pmd_mk_savedwrite(entry); | |
292924b2 PX |
1812 | if (uffd_wp) { |
1813 | entry = pmd_wrprotect(entry); | |
1814 | entry = pmd_mkuffd_wp(entry); | |
1815 | } else if (uffd_wp_resolve) { | |
1816 | /* | |
1817 | * Leave the write bit to be handled by PF interrupt | |
1818 | * handler, then things like COW could be properly | |
1819 | * handled. | |
1820 | */ | |
1821 | entry = pmd_clear_uffd_wp(entry); | |
1822 | } | |
0a85e51d KS |
1823 | ret = HPAGE_PMD_NR; |
1824 | set_pmd_at(mm, addr, pmd, entry); | |
4a18419f | 1825 | |
c9fe6656 NA |
1826 | if (huge_pmd_needs_flush(oldpmd, entry)) |
1827 | tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); | |
4a18419f | 1828 | |
0a85e51d KS |
1829 | BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry)); |
1830 | unlock: | |
1831 | spin_unlock(ptl); | |
025c5b24 NH |
1832 | return ret; |
1833 | } | |
1834 | ||
1835 | /* | |
8f19b0c0 | 1836 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1837 | * |
8f19b0c0 HY |
1838 | * Note that if it returns page table lock pointer, this routine returns without |
1839 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1840 | */ |
b6ec57f4 | 1841 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1842 | { |
b6ec57f4 KS |
1843 | spinlock_t *ptl; |
1844 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1845 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1846 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1847 | return ptl; |
1848 | spin_unlock(ptl); | |
1849 | return NULL; | |
cd7548ab JW |
1850 | } |
1851 | ||
a00cc7d9 MW |
1852 | /* |
1853 | * Returns true if a given pud maps a thp, false otherwise. | |
1854 | * | |
1855 | * Note that if it returns true, this routine returns without unlocking page | |
1856 | * table lock. So callers must unlock it. | |
1857 | */ | |
1858 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1859 | { | |
1860 | spinlock_t *ptl; | |
1861 | ||
1862 | ptl = pud_lock(vma->vm_mm, pud); | |
1863 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1864 | return ptl; | |
1865 | spin_unlock(ptl); | |
1866 | return NULL; | |
1867 | } | |
1868 | ||
1869 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1870 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1871 | pud_t *pud, unsigned long addr) | |
1872 | { | |
a00cc7d9 MW |
1873 | spinlock_t *ptl; |
1874 | ||
1875 | ptl = __pud_trans_huge_lock(pud, vma); | |
1876 | if (!ptl) | |
1877 | return 0; | |
1878 | /* | |
1879 | * For architectures like ppc64 we look at deposited pgtable | |
1880 | * when calling pudp_huge_get_and_clear. So do the | |
1881 | * pgtable_trans_huge_withdraw after finishing pudp related | |
1882 | * operations. | |
1883 | */ | |
70516b93 | 1884 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1885 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1886 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1887 | spin_unlock(ptl); |
1888 | /* No zero page support yet */ | |
1889 | } else { | |
1890 | /* No support for anonymous PUD pages yet */ | |
1891 | BUG(); | |
1892 | } | |
1893 | return 1; | |
1894 | } | |
1895 | ||
1896 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1897 | unsigned long haddr) | |
1898 | { | |
1899 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
1900 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1901 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
1902 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
1903 | ||
ce9311cf | 1904 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
1905 | |
1906 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
1907 | } | |
1908 | ||
1909 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
1910 | unsigned long address) | |
1911 | { | |
1912 | spinlock_t *ptl; | |
ac46d4f3 | 1913 | struct mmu_notifier_range range; |
a00cc7d9 | 1914 | |
7269f999 | 1915 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 1916 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
1917 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
1918 | mmu_notifier_invalidate_range_start(&range); | |
1919 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
1920 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
1921 | goto out; | |
ac46d4f3 | 1922 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
1923 | |
1924 | out: | |
1925 | spin_unlock(ptl); | |
4645b9fe JG |
1926 | /* |
1927 | * No need to double call mmu_notifier->invalidate_range() callback as | |
1928 | * the above pudp_huge_clear_flush_notify() did already call it. | |
1929 | */ | |
ac46d4f3 | 1930 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
1931 | } |
1932 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1933 | ||
eef1b3ba KS |
1934 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
1935 | unsigned long haddr, pmd_t *pmd) | |
1936 | { | |
1937 | struct mm_struct *mm = vma->vm_mm; | |
1938 | pgtable_t pgtable; | |
1939 | pmd_t _pmd; | |
1940 | int i; | |
1941 | ||
0f10851e JG |
1942 | /* |
1943 | * Leave pmd empty until pte is filled note that it is fine to delay | |
1944 | * notification until mmu_notifier_invalidate_range_end() as we are | |
1945 | * replacing a zero pmd write protected page with a zero pte write | |
1946 | * protected page. | |
1947 | * | |
ad56b738 | 1948 | * See Documentation/vm/mmu_notifier.rst |
0f10851e JG |
1949 | */ |
1950 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
1951 | |
1952 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1953 | pmd_populate(mm, &_pmd, pgtable); | |
1954 | ||
1955 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1956 | pte_t *pte, entry; | |
1957 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1958 | entry = pte_mkspecial(entry); | |
1959 | pte = pte_offset_map(&_pmd, haddr); | |
1960 | VM_BUG_ON(!pte_none(*pte)); | |
1961 | set_pte_at(mm, haddr, pte, entry); | |
1962 | pte_unmap(pte); | |
1963 | } | |
1964 | smp_wmb(); /* make pte visible before pmd */ | |
1965 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
1966 | } |
1967 | ||
1968 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 1969 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
1970 | { |
1971 | struct mm_struct *mm = vma->vm_mm; | |
1972 | struct page *page; | |
1973 | pgtable_t pgtable; | |
423ac9af | 1974 | pmd_t old_pmd, _pmd; |
292924b2 | 1975 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
6c287605 | 1976 | bool anon_exclusive = false; |
2ac015e2 | 1977 | unsigned long addr; |
eef1b3ba KS |
1978 | int i; |
1979 | ||
1980 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
1981 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
1982 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
1983 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
1984 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
1985 | |
1986 | count_vm_event(THP_SPLIT_PMD); | |
1987 | ||
d21b9e57 | 1988 | if (!vma_is_anonymous(vma)) { |
99fa8a48 | 1989 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
1990 | /* |
1991 | * We are going to unmap this huge page. So | |
1992 | * just go ahead and zap it | |
1993 | */ | |
1994 | if (arch_needs_pgtable_deposit()) | |
1995 | zap_deposited_table(mm, pmd); | |
2484ca9b | 1996 | if (vma_is_special_huge(vma)) |
d21b9e57 | 1997 | return; |
99fa8a48 HD |
1998 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
1999 | swp_entry_t entry; | |
2000 | ||
2001 | entry = pmd_to_swp_entry(old_pmd); | |
af5cdaf8 | 2002 | page = pfn_swap_entry_to_page(entry); |
99fa8a48 HD |
2003 | } else { |
2004 | page = pmd_page(old_pmd); | |
2005 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2006 | set_page_dirty(page); | |
2007 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2008 | SetPageReferenced(page); | |
cea86fe2 | 2009 | page_remove_rmap(page, vma, true); |
99fa8a48 HD |
2010 | put_page(page); |
2011 | } | |
fadae295 | 2012 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2013 | return; |
99fa8a48 HD |
2014 | } |
2015 | ||
3b77e8c8 | 2016 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2017 | /* |
2018 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2019 | * mmu_notifier_invalidate_range() see comments below inside | |
2020 | * __split_huge_pmd() ? | |
2021 | * | |
2022 | * We are going from a zero huge page write protected to zero | |
2023 | * small page also write protected so it does not seems useful | |
2024 | * to invalidate secondary mmu at this time. | |
2025 | */ | |
eef1b3ba KS |
2026 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2027 | } | |
2028 | ||
423ac9af AK |
2029 | /* |
2030 | * Up to this point the pmd is present and huge and userland has the | |
2031 | * whole access to the hugepage during the split (which happens in | |
2032 | * place). If we overwrite the pmd with the not-huge version pointing | |
2033 | * to the pte here (which of course we could if all CPUs were bug | |
2034 | * free), userland could trigger a small page size TLB miss on the | |
2035 | * small sized TLB while the hugepage TLB entry is still established in | |
2036 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2037 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2038 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2039 | * only safe if the permission and cache attributes of the two entries |
2040 | * loaded in the two TLB is identical (which should be the case here). | |
2041 | * But it is generally safer to never allow small and huge TLB entries | |
2042 | * for the same virtual address to be loaded simultaneously. So instead | |
2043 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2044 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2045 | * must remain set at all times on the pmd until the split is complete | |
2046 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2047 | * non-huge version of the pmd entry with pmd_populate. | |
2048 | */ | |
2049 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2050 | ||
423ac9af | 2051 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2052 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2053 | swp_entry_t entry; |
2054 | ||
423ac9af | 2055 | entry = pmd_to_swp_entry(old_pmd); |
af5cdaf8 | 2056 | page = pfn_swap_entry_to_page(entry); |
4dd845b5 | 2057 | write = is_writable_migration_entry(entry); |
6c287605 DH |
2058 | if (PageAnon(page)) |
2059 | anon_exclusive = is_readable_exclusive_migration_entry(entry); | |
2e83ee1d PX |
2060 | young = false; |
2061 | soft_dirty = pmd_swp_soft_dirty(old_pmd); | |
f45ec5ff | 2062 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2063 | } else { |
423ac9af | 2064 | page = pmd_page(old_pmd); |
2e83ee1d PX |
2065 | if (pmd_dirty(old_pmd)) |
2066 | SetPageDirty(page); | |
2067 | write = pmd_write(old_pmd); | |
2068 | young = pmd_young(old_pmd); | |
2069 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2070 | uffd_wp = pmd_uffd_wp(old_pmd); |
6c287605 | 2071 | |
9d84604b HD |
2072 | VM_BUG_ON_PAGE(!page_count(page), page); |
2073 | page_ref_add(page, HPAGE_PMD_NR - 1); | |
6c287605 DH |
2074 | |
2075 | /* | |
2076 | * Without "freeze", we'll simply split the PMD, propagating the | |
2077 | * PageAnonExclusive() flag for each PTE by setting it for | |
2078 | * each subpage -- no need to (temporarily) clear. | |
2079 | * | |
2080 | * With "freeze" we want to replace mapped pages by | |
2081 | * migration entries right away. This is only possible if we | |
2082 | * managed to clear PageAnonExclusive() -- see | |
2083 | * set_pmd_migration_entry(). | |
2084 | * | |
2085 | * In case we cannot clear PageAnonExclusive(), split the PMD | |
2086 | * only and let try_to_migrate_one() fail later. | |
2087 | */ | |
2088 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); | |
2089 | if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) | |
2090 | freeze = false; | |
2e83ee1d | 2091 | } |
eef1b3ba | 2092 | |
423ac9af AK |
2093 | /* |
2094 | * Withdraw the table only after we mark the pmd entry invalid. | |
2095 | * This's critical for some architectures (Power). | |
2096 | */ | |
eef1b3ba KS |
2097 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2098 | pmd_populate(mm, &_pmd, pgtable); | |
2099 | ||
2ac015e2 | 2100 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2101 | pte_t entry, *pte; |
2102 | /* | |
2103 | * Note that NUMA hinting access restrictions are not | |
2104 | * transferred to avoid any possibility of altering | |
2105 | * permissions across VMAs. | |
2106 | */ | |
84c3fc4e | 2107 | if (freeze || pmd_migration) { |
ba988280 | 2108 | swp_entry_t swp_entry; |
4dd845b5 AP |
2109 | if (write) |
2110 | swp_entry = make_writable_migration_entry( | |
2111 | page_to_pfn(page + i)); | |
6c287605 DH |
2112 | else if (anon_exclusive) |
2113 | swp_entry = make_readable_exclusive_migration_entry( | |
2114 | page_to_pfn(page + i)); | |
4dd845b5 AP |
2115 | else |
2116 | swp_entry = make_readable_migration_entry( | |
2117 | page_to_pfn(page + i)); | |
ba988280 | 2118 | entry = swp_entry_to_pte(swp_entry); |
804dd150 AA |
2119 | if (soft_dirty) |
2120 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2121 | if (uffd_wp) |
2122 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2123 | } else { |
6d2329f8 | 2124 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2125 | entry = maybe_mkwrite(entry, vma); |
6c287605 DH |
2126 | if (anon_exclusive) |
2127 | SetPageAnonExclusive(page + i); | |
ba988280 KS |
2128 | if (!write) |
2129 | entry = pte_wrprotect(entry); | |
2130 | if (!young) | |
2131 | entry = pte_mkold(entry); | |
804dd150 AA |
2132 | if (soft_dirty) |
2133 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2134 | if (uffd_wp) |
2135 | entry = pte_mkuffd_wp(entry); | |
ba988280 | 2136 | } |
2ac015e2 | 2137 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2138 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2139 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2140 | if (!pmd_migration) |
eef1b3ba | 2141 | atomic_inc(&page[i]._mapcount); |
ec0abae6 | 2142 | pte_unmap(pte); |
eef1b3ba KS |
2143 | } |
2144 | ||
ec0abae6 RC |
2145 | if (!pmd_migration) { |
2146 | /* | |
2147 | * Set PG_double_map before dropping compound_mapcount to avoid | |
2148 | * false-negative page_mapped(). | |
2149 | */ | |
2150 | if (compound_mapcount(page) > 1 && | |
2151 | !TestSetPageDoubleMap(page)) { | |
eef1b3ba | 2152 | for (i = 0; i < HPAGE_PMD_NR; i++) |
ec0abae6 RC |
2153 | atomic_inc(&page[i]._mapcount); |
2154 | } | |
2155 | ||
2156 | lock_page_memcg(page); | |
2157 | if (atomic_add_negative(-1, compound_mapcount_ptr(page))) { | |
2158 | /* Last compound_mapcount is gone. */ | |
69473e5d MS |
2159 | __mod_lruvec_page_state(page, NR_ANON_THPS, |
2160 | -HPAGE_PMD_NR); | |
ec0abae6 RC |
2161 | if (TestClearPageDoubleMap(page)) { |
2162 | /* No need in mapcount reference anymore */ | |
2163 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2164 | atomic_dec(&page[i]._mapcount); | |
2165 | } | |
eef1b3ba | 2166 | } |
ec0abae6 | 2167 | unlock_page_memcg(page); |
cea86fe2 HD |
2168 | |
2169 | /* Above is effectively page_remove_rmap(page, vma, true) */ | |
2170 | munlock_vma_page(page, vma, true); | |
eef1b3ba KS |
2171 | } |
2172 | ||
2173 | smp_wmb(); /* make pte visible before pmd */ | |
2174 | pmd_populate(mm, pmd, pgtable); | |
e9b61f19 KS |
2175 | |
2176 | if (freeze) { | |
2ac015e2 | 2177 | for (i = 0; i < HPAGE_PMD_NR; i++) { |
cea86fe2 | 2178 | page_remove_rmap(page + i, vma, false); |
e9b61f19 KS |
2179 | put_page(page + i); |
2180 | } | |
2181 | } | |
eef1b3ba KS |
2182 | } |
2183 | ||
2184 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
af28a988 | 2185 | unsigned long address, bool freeze, struct folio *folio) |
eef1b3ba KS |
2186 | { |
2187 | spinlock_t *ptl; | |
ac46d4f3 | 2188 | struct mmu_notifier_range range; |
eef1b3ba | 2189 | |
7269f999 | 2190 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2191 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2192 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2193 | mmu_notifier_invalidate_range_start(&range); | |
2194 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2195 | |
2196 | /* | |
af28a988 MWO |
2197 | * If caller asks to setup a migration entry, we need a folio to check |
2198 | * pmd against. Otherwise we can end up replacing wrong folio. | |
33f4751e | 2199 | */ |
af28a988 | 2200 | VM_BUG_ON(freeze && !folio); |
83a8441f | 2201 | VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); |
33f4751e | 2202 | |
7f760917 | 2203 | if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || |
83a8441f MWO |
2204 | is_pmd_migration_entry(*pmd)) { |
2205 | if (folio && folio != page_folio(pmd_page(*pmd))) | |
2206 | goto out; | |
7f760917 | 2207 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
83a8441f | 2208 | } |
7f760917 | 2209 | |
e90309c9 | 2210 | out: |
eef1b3ba | 2211 | spin_unlock(ptl); |
4645b9fe JG |
2212 | /* |
2213 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2214 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2215 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2216 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2217 | * fault will trigger a flush_notify before pointing to a new page | |
2218 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2219 | * page in the meantime) | |
2220 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2221 | * to invalidate secondary tlb entry they are all still valid. | |
2222 | * any further changes to individual pte will notify. So no need | |
2223 | * to call mmu_notifier->invalidate_range() | |
2224 | */ | |
ac46d4f3 | 2225 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2226 | } |
2227 | ||
fec89c10 | 2228 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
af28a988 | 2229 | bool freeze, struct folio *folio) |
94fcc585 | 2230 | { |
f72e7dcd | 2231 | pgd_t *pgd; |
c2febafc | 2232 | p4d_t *p4d; |
f72e7dcd | 2233 | pud_t *pud; |
94fcc585 AA |
2234 | pmd_t *pmd; |
2235 | ||
78ddc534 | 2236 | pgd = pgd_offset(vma->vm_mm, address); |
f72e7dcd HD |
2237 | if (!pgd_present(*pgd)) |
2238 | return; | |
2239 | ||
c2febafc KS |
2240 | p4d = p4d_offset(pgd, address); |
2241 | if (!p4d_present(*p4d)) | |
2242 | return; | |
2243 | ||
2244 | pud = pud_offset(p4d, address); | |
f72e7dcd HD |
2245 | if (!pud_present(*pud)) |
2246 | return; | |
2247 | ||
2248 | pmd = pmd_offset(pud, address); | |
fec89c10 | 2249 | |
af28a988 | 2250 | __split_huge_pmd(vma, pmd, address, freeze, folio); |
94fcc585 AA |
2251 | } |
2252 | ||
71f9e58e ML |
2253 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2254 | { | |
2255 | /* | |
2256 | * If the new address isn't hpage aligned and it could previously | |
2257 | * contain an hugepage: check if we need to split an huge pmd. | |
2258 | */ | |
2259 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2260 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2261 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2262 | split_huge_pmd_address(vma, address, false, NULL); | |
2263 | } | |
2264 | ||
e1b9996b | 2265 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2266 | unsigned long start, |
2267 | unsigned long end, | |
2268 | long adjust_next) | |
2269 | { | |
71f9e58e ML |
2270 | /* Check if we need to split start first. */ |
2271 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2272 | |
71f9e58e ML |
2273 | /* Check if we need to split end next. */ |
2274 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2275 | |
2276 | /* | |
71f9e58e ML |
2277 | * If we're also updating the vma->vm_next->vm_start, |
2278 | * check if we need to split it. | |
94fcc585 AA |
2279 | */ |
2280 | if (adjust_next > 0) { | |
2281 | struct vm_area_struct *next = vma->vm_next; | |
2282 | unsigned long nstart = next->vm_start; | |
f9d86a60 | 2283 | nstart += adjust_next; |
71f9e58e | 2284 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2285 | } |
2286 | } | |
e9b61f19 | 2287 | |
906f9cdf | 2288 | static void unmap_page(struct page *page) |
e9b61f19 | 2289 | { |
869f7ee6 | 2290 | struct folio *folio = page_folio(page); |
a98a2f0c AP |
2291 | enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | |
2292 | TTU_SYNC; | |
e9b61f19 KS |
2293 | |
2294 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
2295 | ||
a98a2f0c AP |
2296 | /* |
2297 | * Anon pages need migration entries to preserve them, but file | |
2298 | * pages can simply be left unmapped, then faulted back on demand. | |
2299 | * If that is ever changed (perhaps for mlock), update remap_page(). | |
2300 | */ | |
4b8554c5 MWO |
2301 | if (folio_test_anon(folio)) |
2302 | try_to_migrate(folio, ttu_flags); | |
a98a2f0c | 2303 | else |
869f7ee6 | 2304 | try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); |
e9b61f19 KS |
2305 | } |
2306 | ||
4eecb8b9 | 2307 | static void remap_page(struct folio *folio, unsigned long nr) |
e9b61f19 | 2308 | { |
4eecb8b9 | 2309 | int i = 0; |
ab02c252 | 2310 | |
64b586d1 | 2311 | /* If unmap_page() uses try_to_migrate() on file, remove this check */ |
4eecb8b9 | 2312 | if (!folio_test_anon(folio)) |
ab02c252 | 2313 | return; |
4eecb8b9 MWO |
2314 | for (;;) { |
2315 | remove_migration_ptes(folio, folio, true); | |
2316 | i += folio_nr_pages(folio); | |
2317 | if (i >= nr) | |
2318 | break; | |
2319 | folio = folio_next(folio); | |
ace71a19 | 2320 | } |
e9b61f19 KS |
2321 | } |
2322 | ||
94866635 | 2323 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2324 | struct lruvec *lruvec, struct list_head *list) |
2325 | { | |
94866635 AS |
2326 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2327 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2328 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2329 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2330 | |
6dbb5741 | 2331 | if (list) { |
88dcb9a3 | 2332 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2333 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2334 | get_page(tail); |
2335 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2336 | } else { |
6dbb5741 AS |
2337 | /* head is still on lru (and we have it frozen) */ |
2338 | VM_WARN_ON(!PageLRU(head)); | |
07ca7606 HD |
2339 | if (PageUnevictable(tail)) |
2340 | tail->mlock_count = 0; | |
2341 | else | |
2342 | list_add_tail(&tail->lru, &head->lru); | |
6dbb5741 | 2343 | SetPageLRU(tail); |
88dcb9a3 AS |
2344 | } |
2345 | } | |
2346 | ||
8df651c7 | 2347 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2348 | struct lruvec *lruvec, struct list_head *list) |
2349 | { | |
e9b61f19 KS |
2350 | struct page *page_tail = head + tail; |
2351 | ||
8df651c7 | 2352 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2353 | |
2354 | /* | |
605ca5ed KK |
2355 | * Clone page flags before unfreezing refcount. |
2356 | * | |
2357 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2358 | * for example lock_page() which set PG_waiters. |
6c287605 DH |
2359 | * |
2360 | * Note that for mapped sub-pages of an anonymous THP, | |
2361 | * PG_anon_exclusive has been cleared in unmap_page() and is stored in | |
2362 | * the migration entry instead from where remap_page() will restore it. | |
2363 | * We can still have PG_anon_exclusive set on effectively unmapped and | |
2364 | * unreferenced sub-pages of an anonymous THP: we can simply drop | |
2365 | * PG_anon_exclusive (-> PG_mappedtodisk) for these here. | |
e9b61f19 | 2366 | */ |
e9b61f19 KS |
2367 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2368 | page_tail->flags |= (head->flags & | |
2369 | ((1L << PG_referenced) | | |
2370 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2371 | (1L << PG_swapcache) | |
e9b61f19 KS |
2372 | (1L << PG_mlocked) | |
2373 | (1L << PG_uptodate) | | |
2374 | (1L << PG_active) | | |
1899ad18 | 2375 | (1L << PG_workingset) | |
e9b61f19 | 2376 | (1L << PG_locked) | |
b8d3c4c3 | 2377 | (1L << PG_unevictable) | |
72e6afa0 CM |
2378 | #ifdef CONFIG_64BIT |
2379 | (1L << PG_arch_2) | | |
2380 | #endif | |
b8d3c4c3 | 2381 | (1L << PG_dirty))); |
e9b61f19 | 2382 | |
173d9d9f HD |
2383 | /* ->mapping in first tail page is compound_mapcount */ |
2384 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, | |
2385 | page_tail); | |
2386 | page_tail->mapping = head->mapping; | |
2387 | page_tail->index = head->index + tail; | |
2388 | ||
605ca5ed | 2389 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2390 | smp_wmb(); |
2391 | ||
605ca5ed KK |
2392 | /* |
2393 | * Clear PageTail before unfreezing page refcount. | |
2394 | * | |
2395 | * After successful get_page_unless_zero() might follow put_page() | |
2396 | * which needs correct compound_head(). | |
2397 | */ | |
e9b61f19 KS |
2398 | clear_compound_head(page_tail); |
2399 | ||
605ca5ed KK |
2400 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2401 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2402 | PageSwapCache(head))); | |
2403 | ||
e9b61f19 KS |
2404 | if (page_is_young(head)) |
2405 | set_page_young(page_tail); | |
2406 | if (page_is_idle(head)) | |
2407 | set_page_idle(page_tail); | |
2408 | ||
e9b61f19 | 2409 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2410 | |
2411 | /* | |
2412 | * always add to the tail because some iterators expect new | |
2413 | * pages to show after the currently processed elements - e.g. | |
2414 | * migrate_pages | |
2415 | */ | |
e9b61f19 | 2416 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2417 | } |
2418 | ||
baa355fd | 2419 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2420 | pgoff_t end) |
e9b61f19 | 2421 | { |
e809c3fe MWO |
2422 | struct folio *folio = page_folio(page); |
2423 | struct page *head = &folio->page; | |
e9b61f19 | 2424 | struct lruvec *lruvec; |
4101196b MWO |
2425 | struct address_space *swap_cache = NULL; |
2426 | unsigned long offset = 0; | |
8cce5475 | 2427 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2428 | int i; |
e9b61f19 | 2429 | |
e9b61f19 | 2430 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2431 | split_page_memcg(head, nr); |
e9b61f19 | 2432 | |
4101196b MWO |
2433 | if (PageAnon(head) && PageSwapCache(head)) { |
2434 | swp_entry_t entry = { .val = page_private(head) }; | |
2435 | ||
2436 | offset = swp_offset(entry); | |
2437 | swap_cache = swap_address_space(entry); | |
2438 | xa_lock(&swap_cache->i_pages); | |
2439 | } | |
2440 | ||
f0953a1b | 2441 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
e809c3fe | 2442 | lruvec = folio_lruvec_lock(folio); |
b6769834 | 2443 | |
eac96c3e YS |
2444 | ClearPageHasHWPoisoned(head); |
2445 | ||
8cce5475 | 2446 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2447 | __split_huge_page_tail(head, i, lruvec, list); |
d144bf62 | 2448 | /* Some pages can be beyond EOF: drop them from page cache */ |
baa355fd | 2449 | if (head[i].index >= end) { |
2d077d4b | 2450 | ClearPageDirty(head + i); |
baa355fd | 2451 | __delete_from_page_cache(head + i, NULL); |
d144bf62 | 2452 | if (shmem_mapping(head->mapping)) |
800d8c63 | 2453 | shmem_uncharge(head->mapping->host, 1); |
baa355fd | 2454 | put_page(head + i); |
4101196b MWO |
2455 | } else if (!PageAnon(page)) { |
2456 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2457 | head + i, 0); | |
2458 | } else if (swap_cache) { | |
2459 | __xa_store(&swap_cache->i_pages, offset + i, | |
2460 | head + i, 0); | |
baa355fd KS |
2461 | } |
2462 | } | |
e9b61f19 KS |
2463 | |
2464 | ClearPageCompound(head); | |
6168d0da | 2465 | unlock_page_lruvec(lruvec); |
b6769834 | 2466 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2467 | |
8cce5475 | 2468 | split_page_owner(head, nr); |
f7da677b | 2469 | |
baa355fd KS |
2470 | /* See comment in __split_huge_page_tail() */ |
2471 | if (PageAnon(head)) { | |
aa5dc07f | 2472 | /* Additional pin to swap cache */ |
4101196b | 2473 | if (PageSwapCache(head)) { |
38d8b4e6 | 2474 | page_ref_add(head, 2); |
4101196b MWO |
2475 | xa_unlock(&swap_cache->i_pages); |
2476 | } else { | |
38d8b4e6 | 2477 | page_ref_inc(head); |
4101196b | 2478 | } |
baa355fd | 2479 | } else { |
aa5dc07f | 2480 | /* Additional pin to page cache */ |
baa355fd | 2481 | page_ref_add(head, 2); |
b93b0163 | 2482 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2483 | } |
b6769834 | 2484 | local_irq_enable(); |
e9b61f19 | 2485 | |
4eecb8b9 | 2486 | remap_page(folio, nr); |
e9b61f19 | 2487 | |
c4f9c701 HY |
2488 | if (PageSwapCache(head)) { |
2489 | swp_entry_t entry = { .val = page_private(head) }; | |
2490 | ||
2491 | split_swap_cluster(entry); | |
2492 | } | |
2493 | ||
8cce5475 | 2494 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2495 | struct page *subpage = head + i; |
2496 | if (subpage == page) | |
2497 | continue; | |
2498 | unlock_page(subpage); | |
2499 | ||
2500 | /* | |
2501 | * Subpages may be freed if there wasn't any mapping | |
2502 | * like if add_to_swap() is running on a lru page that | |
2503 | * had its mapping zapped. And freeing these pages | |
2504 | * requires taking the lru_lock so we do the put_page | |
2505 | * of the tail pages after the split is complete. | |
2506 | */ | |
2507 | put_page(subpage); | |
2508 | } | |
2509 | } | |
2510 | ||
b8f593cd | 2511 | /* Racy check whether the huge page can be split */ |
d4b4084a | 2512 | bool can_split_folio(struct folio *folio, int *pextra_pins) |
b8f593cd HY |
2513 | { |
2514 | int extra_pins; | |
2515 | ||
aa5dc07f | 2516 | /* Additional pins from page cache */ |
d4b4084a MWO |
2517 | if (folio_test_anon(folio)) |
2518 | extra_pins = folio_test_swapcache(folio) ? | |
2519 | folio_nr_pages(folio) : 0; | |
b8f593cd | 2520 | else |
d4b4084a | 2521 | extra_pins = folio_nr_pages(folio); |
b8f593cd HY |
2522 | if (pextra_pins) |
2523 | *pextra_pins = extra_pins; | |
d4b4084a | 2524 | return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; |
b8f593cd HY |
2525 | } |
2526 | ||
e9b61f19 KS |
2527 | /* |
2528 | * This function splits huge page into normal pages. @page can point to any | |
2529 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2530 | * | |
2531 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2532 | * The huge page must be locked. | |
2533 | * | |
2534 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2535 | * | |
2536 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2537 | * the hugepage. | |
2538 | * | |
2539 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2540 | * they are not mapped. | |
2541 | * | |
2542 | * Returns 0 if the hugepage is split successfully. | |
2543 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2544 | * us. | |
2545 | */ | |
2546 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2547 | { | |
4eecb8b9 MWO |
2548 | struct folio *folio = page_folio(page); |
2549 | struct page *head = &folio->page; | |
a8803e6c | 2550 | struct deferred_split *ds_queue = get_deferred_split_queue(head); |
6b24ca4a | 2551 | XA_STATE(xas, &head->mapping->i_pages, head->index); |
baa355fd KS |
2552 | struct anon_vma *anon_vma = NULL; |
2553 | struct address_space *mapping = NULL; | |
504e070d | 2554 | int extra_pins, ret; |
006d3ff2 | 2555 | pgoff_t end; |
e9b61f19 | 2556 | |
cb829624 | 2557 | VM_BUG_ON_PAGE(is_huge_zero_page(head), head); |
a8803e6c WY |
2558 | VM_BUG_ON_PAGE(!PageLocked(head), head); |
2559 | VM_BUG_ON_PAGE(!PageCompound(head), head); | |
e9b61f19 | 2560 | |
a8803e6c | 2561 | if (PageWriteback(head)) |
59807685 HY |
2562 | return -EBUSY; |
2563 | ||
baa355fd KS |
2564 | if (PageAnon(head)) { |
2565 | /* | |
c1e8d7c6 | 2566 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2567 | * prevent the anon_vma disappearing so we first we take a |
2568 | * reference to it and then lock the anon_vma for write. This | |
2f031c6f | 2569 | * is similar to folio_lock_anon_vma_read except the write lock |
baa355fd KS |
2570 | * is taken to serialise against parallel split or collapse |
2571 | * operations. | |
2572 | */ | |
2573 | anon_vma = page_get_anon_vma(head); | |
2574 | if (!anon_vma) { | |
2575 | ret = -EBUSY; | |
2576 | goto out; | |
2577 | } | |
006d3ff2 | 2578 | end = -1; |
baa355fd KS |
2579 | mapping = NULL; |
2580 | anon_vma_lock_write(anon_vma); | |
2581 | } else { | |
2582 | mapping = head->mapping; | |
2583 | ||
2584 | /* Truncated ? */ | |
2585 | if (!mapping) { | |
2586 | ret = -EBUSY; | |
2587 | goto out; | |
2588 | } | |
2589 | ||
6b24ca4a MWO |
2590 | xas_split_alloc(&xas, head, compound_order(head), |
2591 | mapping_gfp_mask(mapping) & GFP_RECLAIM_MASK); | |
2592 | if (xas_error(&xas)) { | |
2593 | ret = xas_error(&xas); | |
2594 | goto out; | |
2595 | } | |
2596 | ||
baa355fd KS |
2597 | anon_vma = NULL; |
2598 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2599 | |
2600 | /* | |
2601 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2602 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2603 | * which cannot be nested inside the page tree lock. So note | |
2604 | * end now: i_size itself may be changed at any moment, but | |
2605 | * head page lock is good enough to serialize the trimming. | |
2606 | */ | |
2607 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
d144bf62 HD |
2608 | if (shmem_mapping(mapping)) |
2609 | end = shmem_fallocend(mapping->host, end); | |
e9b61f19 | 2610 | } |
e9b61f19 KS |
2611 | |
2612 | /* | |
906f9cdf | 2613 | * Racy check if we can split the page, before unmap_page() will |
e9b61f19 KS |
2614 | * split PMDs |
2615 | */ | |
d4b4084a | 2616 | if (!can_split_folio(folio, &extra_pins)) { |
e9b61f19 KS |
2617 | ret = -EBUSY; |
2618 | goto out_unlock; | |
2619 | } | |
2620 | ||
906f9cdf | 2621 | unmap_page(head); |
e9b61f19 | 2622 | |
b6769834 AS |
2623 | /* block interrupt reentry in xa_lock and spinlock */ |
2624 | local_irq_disable(); | |
baa355fd | 2625 | if (mapping) { |
baa355fd | 2626 | /* |
aa5dc07f | 2627 | * Check if the head page is present in page cache. |
baa355fd KS |
2628 | * We assume all tail are present too, if head is there. |
2629 | */ | |
6b24ca4a MWO |
2630 | xas_lock(&xas); |
2631 | xas_reset(&xas); | |
aa5dc07f | 2632 | if (xas_load(&xas) != head) |
baa355fd KS |
2633 | goto fail; |
2634 | } | |
2635 | ||
0139aa7b | 2636 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2637 | spin_lock(&ds_queue->split_queue_lock); |
504e070d | 2638 | if (page_ref_freeze(head, 1 + extra_pins)) { |
9a982250 | 2639 | if (!list_empty(page_deferred_list(head))) { |
364c1eeb | 2640 | ds_queue->split_queue_len--; |
9a982250 KS |
2641 | list_del(page_deferred_list(head)); |
2642 | } | |
afb97172 | 2643 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2644 | if (mapping) { |
bf9ecead MS |
2645 | int nr = thp_nr_pages(head); |
2646 | ||
6b24ca4a | 2647 | xas_split(&xas, head, thp_order(head)); |
1ca7554d | 2648 | if (PageSwapBacked(head)) { |
57b2847d MS |
2649 | __mod_lruvec_page_state(head, NR_SHMEM_THPS, |
2650 | -nr); | |
1ca7554d | 2651 | } else { |
bf9ecead MS |
2652 | __mod_lruvec_page_state(head, NR_FILE_THPS, |
2653 | -nr); | |
1ca7554d MS |
2654 | filemap_nr_thps_dec(mapping); |
2655 | } | |
06d3eff6 KS |
2656 | } |
2657 | ||
b6769834 | 2658 | __split_huge_page(page, list, end); |
c4f9c701 | 2659 | ret = 0; |
e9b61f19 | 2660 | } else { |
364c1eeb | 2661 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2662 | fail: |
2663 | if (mapping) | |
6b24ca4a | 2664 | xas_unlock(&xas); |
b6769834 | 2665 | local_irq_enable(); |
4eecb8b9 | 2666 | remap_page(folio, folio_nr_pages(folio)); |
e9b61f19 KS |
2667 | ret = -EBUSY; |
2668 | } | |
2669 | ||
2670 | out_unlock: | |
baa355fd KS |
2671 | if (anon_vma) { |
2672 | anon_vma_unlock_write(anon_vma); | |
2673 | put_anon_vma(anon_vma); | |
2674 | } | |
2675 | if (mapping) | |
2676 | i_mmap_unlock_read(mapping); | |
e9b61f19 | 2677 | out: |
6b24ca4a MWO |
2678 | /* Free any memory we didn't use */ |
2679 | xas_nomem(&xas, 0); | |
e9b61f19 KS |
2680 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); |
2681 | return ret; | |
2682 | } | |
9a982250 KS |
2683 | |
2684 | void free_transhuge_page(struct page *page) | |
2685 | { | |
87eaceb3 | 2686 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2687 | unsigned long flags; |
2688 | ||
364c1eeb | 2689 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2690 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2691 | ds_queue->split_queue_len--; |
9a982250 KS |
2692 | list_del(page_deferred_list(page)); |
2693 | } | |
364c1eeb | 2694 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2695 | free_compound_page(page); |
2696 | } | |
2697 | ||
2698 | void deferred_split_huge_page(struct page *page) | |
2699 | { | |
87eaceb3 YS |
2700 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2701 | #ifdef CONFIG_MEMCG | |
bcfe06bf | 2702 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 | 2703 | #endif |
9a982250 KS |
2704 | unsigned long flags; |
2705 | ||
2706 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2707 | ||
87eaceb3 YS |
2708 | /* |
2709 | * The try_to_unmap() in page reclaim path might reach here too, | |
2710 | * this may cause a race condition to corrupt deferred split queue. | |
2711 | * And, if page reclaim is already handling the same page, it is | |
2712 | * unnecessary to handle it again in shrinker. | |
2713 | * | |
2714 | * Check PageSwapCache to determine if the page is being | |
2715 | * handled by page reclaim since THP swap would add the page into | |
2716 | * swap cache before calling try_to_unmap(). | |
2717 | */ | |
2718 | if (PageSwapCache(page)) | |
2719 | return; | |
2720 | ||
364c1eeb | 2721 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2722 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2723 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2724 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2725 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2726 | #ifdef CONFIG_MEMCG |
2727 | if (memcg) | |
2bfd3637 YS |
2728 | set_shrinker_bit(memcg, page_to_nid(page), |
2729 | deferred_split_shrinker.id); | |
87eaceb3 | 2730 | #endif |
9a982250 | 2731 | } |
364c1eeb | 2732 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2733 | } |
2734 | ||
2735 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2736 | struct shrink_control *sc) | |
2737 | { | |
a3d0a918 | 2738 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2739 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2740 | |
2741 | #ifdef CONFIG_MEMCG | |
2742 | if (sc->memcg) | |
2743 | ds_queue = &sc->memcg->deferred_split_queue; | |
2744 | #endif | |
364c1eeb | 2745 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2746 | } |
2747 | ||
2748 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2749 | struct shrink_control *sc) | |
2750 | { | |
a3d0a918 | 2751 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2752 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2753 | unsigned long flags; |
2754 | LIST_HEAD(list), *pos, *next; | |
2755 | struct page *page; | |
2756 | int split = 0; | |
2757 | ||
87eaceb3 YS |
2758 | #ifdef CONFIG_MEMCG |
2759 | if (sc->memcg) | |
2760 | ds_queue = &sc->memcg->deferred_split_queue; | |
2761 | #endif | |
2762 | ||
364c1eeb | 2763 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2764 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2765 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
dfe5c51c | 2766 | page = list_entry((void *)pos, struct page, deferred_list); |
9a982250 | 2767 | page = compound_head(page); |
e3ae1953 KS |
2768 | if (get_page_unless_zero(page)) { |
2769 | list_move(page_deferred_list(page), &list); | |
2770 | } else { | |
2771 | /* We lost race with put_compound_page() */ | |
9a982250 | 2772 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2773 | ds_queue->split_queue_len--; |
9a982250 | 2774 | } |
e3ae1953 KS |
2775 | if (!--sc->nr_to_scan) |
2776 | break; | |
9a982250 | 2777 | } |
364c1eeb | 2778 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2779 | |
2780 | list_for_each_safe(pos, next, &list) { | |
dfe5c51c | 2781 | page = list_entry((void *)pos, struct page, deferred_list); |
fa41b900 KS |
2782 | if (!trylock_page(page)) |
2783 | goto next; | |
9a982250 KS |
2784 | /* split_huge_page() removes page from list on success */ |
2785 | if (!split_huge_page(page)) | |
2786 | split++; | |
2787 | unlock_page(page); | |
fa41b900 | 2788 | next: |
9a982250 KS |
2789 | put_page(page); |
2790 | } | |
2791 | ||
364c1eeb YS |
2792 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2793 | list_splice_tail(&list, &ds_queue->split_queue); | |
2794 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2795 | |
cb8d68ec KS |
2796 | /* |
2797 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2798 | * This can happen if pages were freed under us. | |
2799 | */ | |
364c1eeb | 2800 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2801 | return SHRINK_STOP; |
2802 | return split; | |
9a982250 KS |
2803 | } |
2804 | ||
2805 | static struct shrinker deferred_split_shrinker = { | |
2806 | .count_objects = deferred_split_count, | |
2807 | .scan_objects = deferred_split_scan, | |
2808 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2809 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2810 | SHRINKER_NONSLAB, | |
9a982250 | 2811 | }; |
49071d43 KS |
2812 | |
2813 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2814 | static void split_huge_pages_all(void) |
49071d43 KS |
2815 | { |
2816 | struct zone *zone; | |
2817 | struct page *page; | |
2818 | unsigned long pfn, max_zone_pfn; | |
2819 | unsigned long total = 0, split = 0; | |
2820 | ||
fa6c0231 | 2821 | pr_debug("Split all THPs\n"); |
49071d43 KS |
2822 | for_each_populated_zone(zone) { |
2823 | max_zone_pfn = zone_end_pfn(zone); | |
2824 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
2825 | if (!pfn_valid(pfn)) | |
2826 | continue; | |
2827 | ||
2828 | page = pfn_to_page(pfn); | |
2829 | if (!get_page_unless_zero(page)) | |
2830 | continue; | |
2831 | ||
2832 | if (zone != page_zone(page)) | |
2833 | goto next; | |
2834 | ||
baa355fd | 2835 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2836 | goto next; |
2837 | ||
2838 | total++; | |
2839 | lock_page(page); | |
2840 | if (!split_huge_page(page)) | |
2841 | split++; | |
2842 | unlock_page(page); | |
2843 | next: | |
2844 | put_page(page); | |
fa6c0231 | 2845 | cond_resched(); |
49071d43 KS |
2846 | } |
2847 | } | |
2848 | ||
fa6c0231 ZY |
2849 | pr_debug("%lu of %lu THP split\n", split, total); |
2850 | } | |
49071d43 | 2851 | |
fa6c0231 ZY |
2852 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2853 | { | |
2854 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2855 | is_vm_hugetlb_page(vma); | |
2856 | } | |
2857 | ||
2858 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2859 | unsigned long vaddr_end) | |
2860 | { | |
2861 | int ret = 0; | |
2862 | struct task_struct *task; | |
2863 | struct mm_struct *mm; | |
2864 | unsigned long total = 0, split = 0; | |
2865 | unsigned long addr; | |
2866 | ||
2867 | vaddr_start &= PAGE_MASK; | |
2868 | vaddr_end &= PAGE_MASK; | |
2869 | ||
2870 | /* Find the task_struct from pid */ | |
2871 | rcu_read_lock(); | |
2872 | task = find_task_by_vpid(pid); | |
2873 | if (!task) { | |
2874 | rcu_read_unlock(); | |
2875 | ret = -ESRCH; | |
2876 | goto out; | |
2877 | } | |
2878 | get_task_struct(task); | |
2879 | rcu_read_unlock(); | |
2880 | ||
2881 | /* Find the mm_struct */ | |
2882 | mm = get_task_mm(task); | |
2883 | put_task_struct(task); | |
2884 | ||
2885 | if (!mm) { | |
2886 | ret = -EINVAL; | |
2887 | goto out; | |
2888 | } | |
2889 | ||
2890 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
2891 | pid, vaddr_start, vaddr_end); | |
2892 | ||
2893 | mmap_read_lock(mm); | |
2894 | /* | |
2895 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
2896 | * table filled with PTE-mapped THPs, each of which is distinct. | |
2897 | */ | |
2898 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
2899 | struct vm_area_struct *vma = find_vma(mm, addr); | |
fa6c0231 ZY |
2900 | struct page *page; |
2901 | ||
2902 | if (!vma || addr < vma->vm_start) | |
2903 | break; | |
2904 | ||
2905 | /* skip special VMA and hugetlb VMA */ | |
2906 | if (vma_not_suitable_for_thp_split(vma)) { | |
2907 | addr = vma->vm_end; | |
2908 | continue; | |
2909 | } | |
2910 | ||
2911 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
87d2762e | 2912 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
fa6c0231 ZY |
2913 | |
2914 | if (IS_ERR(page)) | |
2915 | continue; | |
2916 | if (!page) | |
2917 | continue; | |
2918 | ||
2919 | if (!is_transparent_hugepage(page)) | |
2920 | goto next; | |
2921 | ||
2922 | total++; | |
d4b4084a | 2923 | if (!can_split_folio(page_folio(page), NULL)) |
fa6c0231 ZY |
2924 | goto next; |
2925 | ||
2926 | if (!trylock_page(page)) | |
2927 | goto next; | |
2928 | ||
2929 | if (!split_huge_page(page)) | |
2930 | split++; | |
2931 | ||
2932 | unlock_page(page); | |
2933 | next: | |
2934 | put_page(page); | |
2935 | cond_resched(); | |
2936 | } | |
2937 | mmap_read_unlock(mm); | |
2938 | mmput(mm); | |
2939 | ||
2940 | pr_debug("%lu of %lu THP split\n", split, total); | |
2941 | ||
2942 | out: | |
2943 | return ret; | |
49071d43 | 2944 | } |
fa6c0231 | 2945 | |
fbe37501 ZY |
2946 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
2947 | pgoff_t off_end) | |
2948 | { | |
2949 | struct filename *file; | |
2950 | struct file *candidate; | |
2951 | struct address_space *mapping; | |
2952 | int ret = -EINVAL; | |
2953 | pgoff_t index; | |
2954 | int nr_pages = 1; | |
2955 | unsigned long total = 0, split = 0; | |
2956 | ||
2957 | file = getname_kernel(file_path); | |
2958 | if (IS_ERR(file)) | |
2959 | return ret; | |
2960 | ||
2961 | candidate = file_open_name(file, O_RDONLY, 0); | |
2962 | if (IS_ERR(candidate)) | |
2963 | goto out; | |
2964 | ||
2965 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
2966 | file_path, off_start, off_end); | |
2967 | ||
2968 | mapping = candidate->f_mapping; | |
2969 | ||
2970 | for (index = off_start; index < off_end; index += nr_pages) { | |
2971 | struct page *fpage = pagecache_get_page(mapping, index, | |
2972 | FGP_ENTRY | FGP_HEAD, 0); | |
2973 | ||
2974 | nr_pages = 1; | |
2975 | if (xa_is_value(fpage) || !fpage) | |
2976 | continue; | |
2977 | ||
2978 | if (!is_transparent_hugepage(fpage)) | |
2979 | goto next; | |
2980 | ||
2981 | total++; | |
2982 | nr_pages = thp_nr_pages(fpage); | |
2983 | ||
2984 | if (!trylock_page(fpage)) | |
2985 | goto next; | |
2986 | ||
2987 | if (!split_huge_page(fpage)) | |
2988 | split++; | |
2989 | ||
2990 | unlock_page(fpage); | |
2991 | next: | |
2992 | put_page(fpage); | |
2993 | cond_resched(); | |
2994 | } | |
2995 | ||
2996 | filp_close(candidate, NULL); | |
2997 | ret = 0; | |
2998 | ||
2999 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3000 | out: | |
3001 | putname(file); | |
3002 | return ret; | |
3003 | } | |
3004 | ||
fa6c0231 ZY |
3005 | #define MAX_INPUT_BUF_SZ 255 |
3006 | ||
3007 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3008 | size_t count, loff_t *ppops) | |
3009 | { | |
3010 | static DEFINE_MUTEX(split_debug_mutex); | |
3011 | ssize_t ret; | |
fbe37501 ZY |
3012 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3013 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3014 | int pid; |
3015 | unsigned long vaddr_start, vaddr_end; | |
3016 | ||
3017 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3018 | if (ret) | |
3019 | return ret; | |
3020 | ||
3021 | ret = -EFAULT; | |
3022 | ||
3023 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3024 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3025 | goto out; | |
3026 | ||
3027 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3028 | |
3029 | if (input_buf[0] == '/') { | |
3030 | char *tok; | |
3031 | char *buf = input_buf; | |
3032 | char file_path[MAX_INPUT_BUF_SZ]; | |
3033 | pgoff_t off_start = 0, off_end = 0; | |
3034 | size_t input_len = strlen(input_buf); | |
3035 | ||
3036 | tok = strsep(&buf, ","); | |
3037 | if (tok) { | |
1212e00c | 3038 | strcpy(file_path, tok); |
fbe37501 ZY |
3039 | } else { |
3040 | ret = -EINVAL; | |
3041 | goto out; | |
3042 | } | |
3043 | ||
3044 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3045 | if (ret != 2) { | |
3046 | ret = -EINVAL; | |
3047 | goto out; | |
3048 | } | |
3049 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3050 | if (!ret) | |
3051 | ret = input_len; | |
3052 | ||
3053 | goto out; | |
3054 | } | |
3055 | ||
fa6c0231 ZY |
3056 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3057 | if (ret == 1 && pid == 1) { | |
3058 | split_huge_pages_all(); | |
3059 | ret = strlen(input_buf); | |
3060 | goto out; | |
3061 | } else if (ret != 3) { | |
3062 | ret = -EINVAL; | |
3063 | goto out; | |
3064 | } | |
3065 | ||
3066 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3067 | if (!ret) | |
3068 | ret = strlen(input_buf); | |
3069 | out: | |
3070 | mutex_unlock(&split_debug_mutex); | |
3071 | return ret; | |
3072 | ||
3073 | } | |
3074 | ||
3075 | static const struct file_operations split_huge_pages_fops = { | |
3076 | .owner = THIS_MODULE, | |
3077 | .write = split_huge_pages_write, | |
3078 | .llseek = no_llseek, | |
3079 | }; | |
49071d43 KS |
3080 | |
3081 | static int __init split_huge_pages_debugfs(void) | |
3082 | { | |
d9f7979c GKH |
3083 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3084 | &split_huge_pages_fops); | |
49071d43 KS |
3085 | return 0; |
3086 | } | |
3087 | late_initcall(split_huge_pages_debugfs); | |
3088 | #endif | |
616b8371 ZY |
3089 | |
3090 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
7f5abe60 | 3091 | int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, |
616b8371 ZY |
3092 | struct page *page) |
3093 | { | |
3094 | struct vm_area_struct *vma = pvmw->vma; | |
3095 | struct mm_struct *mm = vma->vm_mm; | |
3096 | unsigned long address = pvmw->address; | |
6c287605 | 3097 | bool anon_exclusive; |
616b8371 ZY |
3098 | pmd_t pmdval; |
3099 | swp_entry_t entry; | |
ab6e3d09 | 3100 | pmd_t pmdswp; |
616b8371 ZY |
3101 | |
3102 | if (!(pvmw->pmd && !pvmw->pte)) | |
7f5abe60 | 3103 | return 0; |
616b8371 | 3104 | |
616b8371 | 3105 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3106 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
6c287605 DH |
3107 | |
3108 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); | |
3109 | if (anon_exclusive && page_try_share_anon_rmap(page)) { | |
3110 | set_pmd_at(mm, address, pvmw->pmd, pmdval); | |
7f5abe60 | 3111 | return -EBUSY; |
6c287605 DH |
3112 | } |
3113 | ||
616b8371 ZY |
3114 | if (pmd_dirty(pmdval)) |
3115 | set_page_dirty(page); | |
4dd845b5 AP |
3116 | if (pmd_write(pmdval)) |
3117 | entry = make_writable_migration_entry(page_to_pfn(page)); | |
6c287605 DH |
3118 | else if (anon_exclusive) |
3119 | entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); | |
4dd845b5 AP |
3120 | else |
3121 | entry = make_readable_migration_entry(page_to_pfn(page)); | |
ab6e3d09 NH |
3122 | pmdswp = swp_entry_to_pmd(entry); |
3123 | if (pmd_soft_dirty(pmdval)) | |
3124 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3125 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
cea86fe2 | 3126 | page_remove_rmap(page, vma, true); |
616b8371 | 3127 | put_page(page); |
283fd6fe | 3128 | trace_set_migration_pmd(address, pmd_val(pmdswp)); |
7f5abe60 DH |
3129 | |
3130 | return 0; | |
616b8371 ZY |
3131 | } |
3132 | ||
3133 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3134 | { | |
3135 | struct vm_area_struct *vma = pvmw->vma; | |
3136 | struct mm_struct *mm = vma->vm_mm; | |
3137 | unsigned long address = pvmw->address; | |
3138 | unsigned long mmun_start = address & HPAGE_PMD_MASK; | |
3139 | pmd_t pmde; | |
3140 | swp_entry_t entry; | |
3141 | ||
3142 | if (!(pvmw->pmd && !pvmw->pte)) | |
3143 | return; | |
3144 | ||
3145 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3146 | get_page(new); | |
3147 | pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); | |
ab6e3d09 NH |
3148 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3149 | pmde = pmd_mksoft_dirty(pmde); | |
4dd845b5 | 3150 | if (is_writable_migration_entry(entry)) |
f55e1014 | 3151 | pmde = maybe_pmd_mkwrite(pmde, vma); |
8f34f1ea PX |
3152 | if (pmd_swp_uffd_wp(*pvmw->pmd)) |
3153 | pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); | |
616b8371 | 3154 | |
6c287605 DH |
3155 | if (PageAnon(new)) { |
3156 | rmap_t rmap_flags = RMAP_COMPOUND; | |
3157 | ||
3158 | if (!is_readable_migration_entry(entry)) | |
3159 | rmap_flags |= RMAP_EXCLUSIVE; | |
3160 | ||
3161 | page_add_anon_rmap(new, vma, mmun_start, rmap_flags); | |
3162 | } else { | |
cea86fe2 | 3163 | page_add_file_rmap(new, vma, true); |
6c287605 DH |
3164 | } |
3165 | VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); | |
616b8371 | 3166 | set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); |
5cbcf225 MS |
3167 | |
3168 | /* No need to invalidate - it was non-present before */ | |
616b8371 | 3169 | update_mmu_cache_pmd(vma, address, pvmw->pmd); |
283fd6fe | 3170 | trace_remove_migration_pmd(address, pmd_val(pmde)); |
616b8371 ZY |
3171 | } |
3172 | #endif |