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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> |
fb5c2029 | 21 | #include <linux/backing-dev.h> |
4897c765 | 22 | #include <linux/dax.h> |
ba76149f | 23 | #include <linux/khugepaged.h> |
878aee7d | 24 | #include <linux/freezer.h> |
f25748e3 | 25 | #include <linux/pfn_t.h> |
a664b2d8 | 26 | #include <linux/mman.h> |
3565fce3 | 27 | #include <linux/memremap.h> |
325adeb5 | 28 | #include <linux/pagemap.h> |
49071d43 | 29 | #include <linux/debugfs.h> |
4daae3b4 | 30 | #include <linux/migrate.h> |
43b5fbbd | 31 | #include <linux/hashtable.h> |
6b251fc9 | 32 | #include <linux/userfaultfd_k.h> |
33c3fc71 | 33 | #include <linux/page_idle.h> |
baa355fd | 34 | #include <linux/shmem_fs.h> |
6b31d595 | 35 | #include <linux/oom.h> |
98fa15f3 | 36 | #include <linux/numa.h> |
f7da677b | 37 | #include <linux/page_owner.h> |
a1a3a2fc | 38 | #include <linux/sched/sysctl.h> |
467b171a | 39 | #include <linux/memory-tiers.h> |
97ae1749 | 40 | |
71e3aac0 AA |
41 | #include <asm/tlb.h> |
42 | #include <asm/pgalloc.h> | |
43 | #include "internal.h" | |
014bb1de | 44 | #include "swap.h" |
71e3aac0 | 45 | |
283fd6fe AK |
46 | #define CREATE_TRACE_POINTS |
47 | #include <trace/events/thp.h> | |
48 | ||
ba76149f | 49 | /* |
b14d595a MD |
50 | * By default, transparent hugepage support is disabled in order to avoid |
51 | * risking an increased memory footprint for applications that are not | |
52 | * guaranteed to benefit from it. When transparent hugepage support is | |
53 | * enabled, it is for all mappings, and khugepaged scans all mappings. | |
8bfa3f9a JW |
54 | * Defrag is invoked by khugepaged hugepage allocations and by page faults |
55 | * for all hugepage allocations. | |
ba76149f | 56 | */ |
71e3aac0 | 57 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 58 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 59 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
60 | #endif |
61 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
62 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
63 | #endif | |
444eb2a4 | 64 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)| |
79da5407 KS |
65 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
66 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f | 67 | |
9a982250 | 68 | static struct shrinker deferred_split_shrinker; |
f000565a | 69 | |
97ae1749 | 70 | static atomic_t huge_zero_refcount; |
56873f43 | 71 | struct page *huge_zero_page __read_mostly; |
3b77e8c8 | 72 | unsigned long huge_zero_pfn __read_mostly = ~0UL; |
4a6c1297 | 73 | |
a7f4e6e4 ZK |
74 | bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, |
75 | bool smaps, bool in_pf, bool enforce_sysfs) | |
7635d9cb | 76 | { |
9fec5168 YS |
77 | if (!vma->vm_mm) /* vdso */ |
78 | return false; | |
79 | ||
7da4e2cb YS |
80 | /* |
81 | * Explicitly disabled through madvise or prctl, or some | |
82 | * architectures may disable THP for some mappings, for | |
83 | * example, s390 kvm. | |
84 | * */ | |
85 | if ((vm_flags & VM_NOHUGEPAGE) || | |
86 | test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) | |
9fec5168 | 87 | return false; |
7da4e2cb YS |
88 | /* |
89 | * If the hardware/firmware marked hugepage support disabled. | |
90 | */ | |
91 | if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX)) | |
c0630669 | 92 | return false; |
c0630669 | 93 | |
7da4e2cb | 94 | /* khugepaged doesn't collapse DAX vma, but page fault is fine. */ |
9fec5168 | 95 | if (vma_is_dax(vma)) |
7da4e2cb YS |
96 | return in_pf; |
97 | ||
98 | /* | |
99 | * Special VMA and hugetlb VMA. | |
100 | * Must be checked after dax since some dax mappings may have | |
101 | * VM_MIXEDMAP set. | |
102 | */ | |
103 | if (vm_flags & VM_NO_KHUGEPAGED) | |
c0630669 | 104 | return false; |
9fec5168 | 105 | |
7da4e2cb YS |
106 | /* |
107 | * Check alignment for file vma and size for both file and anon vma. | |
108 | * | |
109 | * Skip the check for page fault. Huge fault does the check in fault | |
110 | * handlers. And this check is not suitable for huge PUD fault. | |
111 | */ | |
112 | if (!in_pf && | |
113 | !transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE))) | |
9fec5168 YS |
114 | return false; |
115 | ||
7da4e2cb YS |
116 | /* |
117 | * Enabled via shmem mount options or sysfs settings. | |
118 | * Must be done before hugepage flags check since shmem has its | |
119 | * own flags. | |
120 | */ | |
121 | if (!in_pf && shmem_file(vma->vm_file)) | |
2cf13384 DS |
122 | return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, |
123 | !enforce_sysfs, vma->vm_mm, vm_flags); | |
9fec5168 | 124 | |
a7f4e6e4 ZK |
125 | /* Enforce sysfs THP requirements as necessary */ |
126 | if (enforce_sysfs && | |
127 | (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && | |
128 | !hugepage_flags_always()))) | |
9fec5168 YS |
129 | return false; |
130 | ||
131 | /* Only regular file is valid */ | |
7da4e2cb | 132 | if (!in_pf && file_thp_enabled(vma)) |
78d12c19 | 133 | return true; |
7635d9cb | 134 | |
9fec5168 YS |
135 | if (!vma_is_anonymous(vma)) |
136 | return false; | |
137 | ||
138 | if (vma_is_temporary_stack(vma)) | |
139 | return false; | |
140 | ||
141 | /* | |
142 | * THPeligible bit of smaps should show 1 for proper VMAs even | |
143 | * though anon_vma is not initialized yet. | |
7da4e2cb YS |
144 | * |
145 | * Allow page fault since anon_vma may be not initialized until | |
146 | * the first page fault. | |
9fec5168 YS |
147 | */ |
148 | if (!vma->anon_vma) | |
7da4e2cb | 149 | return (smaps || in_pf); |
9fec5168 YS |
150 | |
151 | return true; | |
7635d9cb MH |
152 | } |
153 | ||
aaa9705b | 154 | static bool get_huge_zero_page(void) |
97ae1749 KS |
155 | { |
156 | struct page *zero_page; | |
157 | retry: | |
158 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 159 | return true; |
97ae1749 KS |
160 | |
161 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 162 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
163 | if (!zero_page) { |
164 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 165 | return false; |
d8a8e1f0 | 166 | } |
97ae1749 | 167 | preempt_disable(); |
5918d10a | 168 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 169 | preempt_enable(); |
5ddacbe9 | 170 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
171 | goto retry; |
172 | } | |
3b77e8c8 | 173 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
174 | |
175 | /* We take additional reference here. It will be put back by shrinker */ | |
176 | atomic_set(&huge_zero_refcount, 2); | |
177 | preempt_enable(); | |
f4981502 | 178 | count_vm_event(THP_ZERO_PAGE_ALLOC); |
aaa9705b | 179 | return true; |
4a6c1297 KS |
180 | } |
181 | ||
6fcb52a5 | 182 | static void put_huge_zero_page(void) |
4a6c1297 | 183 | { |
97ae1749 KS |
184 | /* |
185 | * Counter should never go to zero here. Only shrinker can put | |
186 | * last reference. | |
187 | */ | |
188 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
189 | } |
190 | ||
6fcb52a5 AL |
191 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
192 | { | |
193 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
194 | return READ_ONCE(huge_zero_page); | |
195 | ||
196 | if (!get_huge_zero_page()) | |
197 | return NULL; | |
198 | ||
199 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
200 | put_huge_zero_page(); | |
201 | ||
202 | return READ_ONCE(huge_zero_page); | |
203 | } | |
204 | ||
205 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
206 | { | |
207 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
208 | put_huge_zero_page(); | |
209 | } | |
210 | ||
48896466 GC |
211 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
212 | struct shrink_control *sc) | |
4a6c1297 | 213 | { |
48896466 GC |
214 | /* we can free zero page only if last reference remains */ |
215 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
216 | } | |
97ae1749 | 217 | |
48896466 GC |
218 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
219 | struct shrink_control *sc) | |
220 | { | |
97ae1749 | 221 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
222 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
223 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 224 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 225 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 226 | return HPAGE_PMD_NR; |
97ae1749 KS |
227 | } |
228 | ||
229 | return 0; | |
4a6c1297 KS |
230 | } |
231 | ||
97ae1749 | 232 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
233 | .count_objects = shrink_huge_zero_page_count, |
234 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
235 | .seeks = DEFAULT_SEEKS, |
236 | }; | |
237 | ||
71e3aac0 | 238 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
239 | static ssize_t enabled_show(struct kobject *kobj, |
240 | struct kobj_attribute *attr, char *buf) | |
241 | { | |
bfb0ffeb JP |
242 | const char *output; |
243 | ||
444eb2a4 | 244 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
245 | output = "[always] madvise never"; |
246 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
247 | &transparent_hugepage_flags)) | |
248 | output = "always [madvise] never"; | |
444eb2a4 | 249 | else |
bfb0ffeb JP |
250 | output = "always madvise [never]"; |
251 | ||
252 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 253 | } |
444eb2a4 | 254 | |
71e3aac0 AA |
255 | static ssize_t enabled_store(struct kobject *kobj, |
256 | struct kobj_attribute *attr, | |
257 | const char *buf, size_t count) | |
258 | { | |
21440d7e | 259 | ssize_t ret = count; |
ba76149f | 260 | |
f42f2552 | 261 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
262 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
263 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 264 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
265 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
266 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 267 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
268 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
269 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
270 | } else | |
271 | ret = -EINVAL; | |
ba76149f AA |
272 | |
273 | if (ret > 0) { | |
b46e756f | 274 | int err = start_stop_khugepaged(); |
ba76149f AA |
275 | if (err) |
276 | ret = err; | |
277 | } | |
ba76149f | 278 | return ret; |
71e3aac0 | 279 | } |
37139bb0 ML |
280 | |
281 | static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); | |
71e3aac0 | 282 | |
b46e756f | 283 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
284 | struct kobj_attribute *attr, char *buf, |
285 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 286 | { |
bfb0ffeb JP |
287 | return sysfs_emit(buf, "%d\n", |
288 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 289 | } |
e27e6151 | 290 | |
b46e756f | 291 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
292 | struct kobj_attribute *attr, |
293 | const char *buf, size_t count, | |
294 | enum transparent_hugepage_flag flag) | |
295 | { | |
e27e6151 BH |
296 | unsigned long value; |
297 | int ret; | |
298 | ||
299 | ret = kstrtoul(buf, 10, &value); | |
300 | if (ret < 0) | |
301 | return ret; | |
302 | if (value > 1) | |
303 | return -EINVAL; | |
304 | ||
305 | if (value) | |
71e3aac0 | 306 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 307 | else |
71e3aac0 | 308 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
309 | |
310 | return count; | |
311 | } | |
312 | ||
71e3aac0 AA |
313 | static ssize_t defrag_show(struct kobject *kobj, |
314 | struct kobj_attribute *attr, char *buf) | |
315 | { | |
bfb0ffeb JP |
316 | const char *output; |
317 | ||
318 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
319 | &transparent_hugepage_flags)) | |
320 | output = "[always] defer defer+madvise madvise never"; | |
321 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
322 | &transparent_hugepage_flags)) | |
323 | output = "always [defer] defer+madvise madvise never"; | |
324 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
325 | &transparent_hugepage_flags)) | |
326 | output = "always defer [defer+madvise] madvise never"; | |
327 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
328 | &transparent_hugepage_flags)) | |
329 | output = "always defer defer+madvise [madvise] never"; | |
330 | else | |
331 | output = "always defer defer+madvise madvise [never]"; | |
332 | ||
333 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 334 | } |
21440d7e | 335 | |
71e3aac0 AA |
336 | static ssize_t defrag_store(struct kobject *kobj, |
337 | struct kobj_attribute *attr, | |
338 | const char *buf, size_t count) | |
339 | { | |
f42f2552 | 340 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
341 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
342 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
343 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
344 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 345 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
346 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
347 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
348 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
349 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 350 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
351 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
352 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
353 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
354 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 355 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
356 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
357 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
358 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
359 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 360 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
361 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
362 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
363 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
364 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
365 | } else | |
366 | return -EINVAL; | |
367 | ||
368 | return count; | |
71e3aac0 | 369 | } |
37139bb0 | 370 | static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); |
71e3aac0 | 371 | |
79da5407 | 372 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 373 | struct kobj_attribute *attr, char *buf) |
79da5407 | 374 | { |
b46e756f | 375 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 376 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
377 | } |
378 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
379 | struct kobj_attribute *attr, const char *buf, size_t count) | |
380 | { | |
b46e756f | 381 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
382 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
383 | } | |
37139bb0 | 384 | static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); |
49920d28 HD |
385 | |
386 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 387 | struct kobj_attribute *attr, char *buf) |
49920d28 | 388 | { |
ae7a927d | 389 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
390 | } |
391 | static struct kobj_attribute hpage_pmd_size_attr = | |
392 | __ATTR_RO(hpage_pmd_size); | |
393 | ||
71e3aac0 AA |
394 | static struct attribute *hugepage_attr[] = { |
395 | &enabled_attr.attr, | |
396 | &defrag_attr.attr, | |
79da5407 | 397 | &use_zero_page_attr.attr, |
49920d28 | 398 | &hpage_pmd_size_attr.attr, |
396bcc52 | 399 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 400 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
401 | #endif |
402 | NULL, | |
403 | }; | |
404 | ||
8aa95a21 | 405 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 406 | .attrs = hugepage_attr, |
ba76149f AA |
407 | }; |
408 | ||
569e5590 | 409 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 410 | { |
71e3aac0 AA |
411 | int err; |
412 | ||
569e5590 SL |
413 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
414 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 415 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 416 | return -ENOMEM; |
ba76149f AA |
417 | } |
418 | ||
569e5590 | 419 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 420 | if (err) { |
ae3a8c1c | 421 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 422 | goto delete_obj; |
ba76149f AA |
423 | } |
424 | ||
569e5590 | 425 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 426 | if (err) { |
ae3a8c1c | 427 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 428 | goto remove_hp_group; |
ba76149f | 429 | } |
569e5590 SL |
430 | |
431 | return 0; | |
432 | ||
433 | remove_hp_group: | |
434 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
435 | delete_obj: | |
436 | kobject_put(*hugepage_kobj); | |
437 | return err; | |
438 | } | |
439 | ||
440 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
441 | { | |
442 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
443 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
444 | kobject_put(hugepage_kobj); | |
445 | } | |
446 | #else | |
447 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
448 | { | |
449 | return 0; | |
450 | } | |
451 | ||
452 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
453 | { | |
454 | } | |
455 | #endif /* CONFIG_SYSFS */ | |
456 | ||
457 | static int __init hugepage_init(void) | |
458 | { | |
459 | int err; | |
460 | struct kobject *hugepage_kobj; | |
461 | ||
462 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
463 | /* |
464 | * Hardware doesn't support hugepages, hence disable | |
465 | * DAX PMD support. | |
466 | */ | |
467 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
468 | return -EINVAL; |
469 | } | |
470 | ||
ff20c2e0 KS |
471 | /* |
472 | * hugepages can't be allocated by the buddy allocator | |
473 | */ | |
474 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
475 | /* | |
476 | * we use page->mapping and page->index in second tail page | |
477 | * as list_head: assuming THP order >= 2 | |
478 | */ | |
479 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
480 | ||
569e5590 SL |
481 | err = hugepage_init_sysfs(&hugepage_kobj); |
482 | if (err) | |
65ebb64f | 483 | goto err_sysfs; |
ba76149f | 484 | |
b46e756f | 485 | err = khugepaged_init(); |
ba76149f | 486 | if (err) |
65ebb64f | 487 | goto err_slab; |
ba76149f | 488 | |
e33c267a | 489 | err = register_shrinker(&huge_zero_page_shrinker, "thp-zero"); |
65ebb64f KS |
490 | if (err) |
491 | goto err_hzp_shrinker; | |
e33c267a | 492 | err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split"); |
9a982250 KS |
493 | if (err) |
494 | goto err_split_shrinker; | |
97ae1749 | 495 | |
97562cd2 RR |
496 | /* |
497 | * By default disable transparent hugepages on smaller systems, | |
498 | * where the extra memory used could hurt more than TLB overhead | |
499 | * is likely to save. The admin can still enable it through /sys. | |
500 | */ | |
ca79b0c2 | 501 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 502 | transparent_hugepage_flags = 0; |
79553da2 KS |
503 | return 0; |
504 | } | |
97562cd2 | 505 | |
79553da2 | 506 | err = start_stop_khugepaged(); |
65ebb64f KS |
507 | if (err) |
508 | goto err_khugepaged; | |
ba76149f | 509 | |
569e5590 | 510 | return 0; |
65ebb64f | 511 | err_khugepaged: |
9a982250 KS |
512 | unregister_shrinker(&deferred_split_shrinker); |
513 | err_split_shrinker: | |
65ebb64f KS |
514 | unregister_shrinker(&huge_zero_page_shrinker); |
515 | err_hzp_shrinker: | |
b46e756f | 516 | khugepaged_destroy(); |
65ebb64f | 517 | err_slab: |
569e5590 | 518 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 519 | err_sysfs: |
ba76149f | 520 | return err; |
71e3aac0 | 521 | } |
a64fb3cd | 522 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
523 | |
524 | static int __init setup_transparent_hugepage(char *str) | |
525 | { | |
526 | int ret = 0; | |
527 | if (!str) | |
528 | goto out; | |
529 | if (!strcmp(str, "always")) { | |
530 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
531 | &transparent_hugepage_flags); | |
532 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
533 | &transparent_hugepage_flags); | |
534 | ret = 1; | |
535 | } else if (!strcmp(str, "madvise")) { | |
536 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
537 | &transparent_hugepage_flags); | |
538 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
539 | &transparent_hugepage_flags); | |
540 | ret = 1; | |
541 | } else if (!strcmp(str, "never")) { | |
542 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
543 | &transparent_hugepage_flags); | |
544 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
545 | &transparent_hugepage_flags); | |
546 | ret = 1; | |
547 | } | |
548 | out: | |
549 | if (!ret) | |
ae3a8c1c | 550 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
551 | return ret; |
552 | } | |
553 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
554 | ||
f55e1014 | 555 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 556 | { |
f55e1014 | 557 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
558 | pmd = pmd_mkwrite(pmd); |
559 | return pmd; | |
560 | } | |
561 | ||
87eaceb3 | 562 | #ifdef CONFIG_MEMCG |
f8baa6be MWO |
563 | static inline |
564 | struct deferred_split *get_deferred_split_queue(struct folio *folio) | |
9a982250 | 565 | { |
f8baa6be MWO |
566 | struct mem_cgroup *memcg = folio_memcg(folio); |
567 | struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); | |
87eaceb3 YS |
568 | |
569 | if (memcg) | |
570 | return &memcg->deferred_split_queue; | |
571 | else | |
572 | return &pgdat->deferred_split_queue; | |
9a982250 | 573 | } |
87eaceb3 | 574 | #else |
f8baa6be MWO |
575 | static inline |
576 | struct deferred_split *get_deferred_split_queue(struct folio *folio) | |
87eaceb3 | 577 | { |
f8baa6be | 578 | struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); |
87eaceb3 YS |
579 | |
580 | return &pgdat->deferred_split_queue; | |
581 | } | |
582 | #endif | |
9a982250 KS |
583 | |
584 | void prep_transhuge_page(struct page *page) | |
585 | { | |
8991de90 | 586 | struct folio *folio = (struct folio *)page; |
9a982250 | 587 | |
8991de90 MWO |
588 | VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); |
589 | INIT_LIST_HEAD(&folio->_deferred_list); | |
9a982250 KS |
590 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); |
591 | } | |
592 | ||
562beb72 | 593 | static inline bool is_transparent_hugepage(struct page *page) |
005ba37c | 594 | { |
f04029f3 MWO |
595 | struct folio *folio; |
596 | ||
005ba37c | 597 | if (!PageCompound(page)) |
fa1f68cc | 598 | return false; |
005ba37c | 599 | |
f04029f3 MWO |
600 | folio = page_folio(page); |
601 | return is_huge_zero_page(&folio->page) || | |
602 | folio->_folio_dtor == TRANSHUGE_PAGE_DTOR; | |
005ba37c | 603 | } |
005ba37c | 604 | |
97d3d0f9 KS |
605 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
606 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
607 | loff_t off, unsigned long flags, unsigned long size) |
608 | { | |
74d2fad1 TK |
609 | loff_t off_end = off + len; |
610 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 611 | unsigned long len_pad, ret; |
74d2fad1 TK |
612 | |
613 | if (off_end <= off_align || (off_end - off_align) < size) | |
614 | return 0; | |
615 | ||
616 | len_pad = len + size; | |
617 | if (len_pad < len || (off + len_pad) < off) | |
618 | return 0; | |
619 | ||
97d3d0f9 | 620 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 621 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
622 | |
623 | /* | |
624 | * The failure might be due to length padding. The caller will retry | |
625 | * without the padding. | |
626 | */ | |
627 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
628 | return 0; |
629 | ||
97d3d0f9 KS |
630 | /* |
631 | * Do not try to align to THP boundary if allocation at the address | |
632 | * hint succeeds. | |
633 | */ | |
634 | if (ret == addr) | |
635 | return addr; | |
636 | ||
637 | ret += (off - ret) & (size - 1); | |
638 | return ret; | |
74d2fad1 TK |
639 | } |
640 | ||
641 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
642 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
643 | { | |
97d3d0f9 | 644 | unsigned long ret; |
74d2fad1 TK |
645 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
646 | ||
97d3d0f9 KS |
647 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
648 | if (ret) | |
649 | return ret; | |
1854bc6e | 650 | |
74d2fad1 TK |
651 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
652 | } | |
653 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
654 | ||
2b740303 SJ |
655 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
656 | struct page *page, gfp_t gfp) | |
71e3aac0 | 657 | { |
82b0f8c3 | 658 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 659 | pgtable_t pgtable; |
82b0f8c3 | 660 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 661 | vm_fault_t ret = 0; |
71e3aac0 | 662 | |
309381fe | 663 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 664 | |
8f425e4e | 665 | if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { |
6b251fc9 AA |
666 | put_page(page); |
667 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 668 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
669 | return VM_FAULT_FALLBACK; |
670 | } | |
9d82c694 | 671 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 672 | |
4cf58924 | 673 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 674 | if (unlikely(!pgtable)) { |
6b31d595 MH |
675 | ret = VM_FAULT_OOM; |
676 | goto release; | |
00501b53 | 677 | } |
71e3aac0 | 678 | |
c79b57e4 | 679 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
680 | /* |
681 | * The memory barrier inside __SetPageUptodate makes sure that | |
682 | * clear_huge_page writes become visible before the set_pmd_at() | |
683 | * write. | |
684 | */ | |
71e3aac0 AA |
685 | __SetPageUptodate(page); |
686 | ||
82b0f8c3 JK |
687 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
688 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 689 | goto unlock_release; |
71e3aac0 AA |
690 | } else { |
691 | pmd_t entry; | |
6b251fc9 | 692 | |
6b31d595 MH |
693 | ret = check_stable_address_space(vma->vm_mm); |
694 | if (ret) | |
695 | goto unlock_release; | |
696 | ||
6b251fc9 AA |
697 | /* Deliver the page fault to userland */ |
698 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 699 | spin_unlock(vmf->ptl); |
6b251fc9 | 700 | put_page(page); |
bae473a4 | 701 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
702 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
703 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
704 | return ret; | |
6b251fc9 AA |
705 | } |
706 | ||
3122359a | 707 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 708 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
40f2bbf7 | 709 | page_add_new_anon_rmap(page, vma, haddr); |
b518154e | 710 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
711 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
712 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 713 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 714 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 715 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 716 | spin_unlock(vmf->ptl); |
6b251fc9 | 717 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 718 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
719 | } |
720 | ||
aa2e878e | 721 | return 0; |
6b31d595 MH |
722 | unlock_release: |
723 | spin_unlock(vmf->ptl); | |
724 | release: | |
725 | if (pgtable) | |
726 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
727 | put_page(page); |
728 | return ret; | |
729 | ||
71e3aac0 AA |
730 | } |
731 | ||
444eb2a4 | 732 | /* |
21440d7e DR |
733 | * always: directly stall for all thp allocations |
734 | * defer: wake kswapd and fail if not immediately available | |
735 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
736 | * fail if not immediately available | |
737 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
738 | * available | |
739 | * never: never stall for any thp allocation | |
444eb2a4 | 740 | */ |
164cc4fe | 741 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 742 | { |
164cc4fe | 743 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 744 | |
ac79f78d | 745 | /* Always do synchronous compaction */ |
a8282608 AA |
746 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
747 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
748 | |
749 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 750 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 751 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
752 | |
753 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 754 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
755 | return GFP_TRANSHUGE_LIGHT | |
756 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
757 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
758 | |
759 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 760 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
761 | return GFP_TRANSHUGE_LIGHT | |
762 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 763 | |
19deb769 | 764 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
765 | } |
766 | ||
c4088ebd | 767 | /* Caller must hold page table lock. */ |
2efeb8da | 768 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 769 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 770 | struct page *zero_page) |
fc9fe822 KS |
771 | { |
772 | pmd_t entry; | |
7c414164 | 773 | if (!pmd_none(*pmd)) |
2efeb8da | 774 | return; |
5918d10a | 775 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 776 | entry = pmd_mkhuge(entry); |
c8bb4163 | 777 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 778 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 779 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
780 | } |
781 | ||
2b740303 | 782 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 783 | { |
82b0f8c3 | 784 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 785 | gfp_t gfp; |
cb196ee1 | 786 | struct folio *folio; |
82b0f8c3 | 787 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 788 | |
43675e6f | 789 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 790 | return VM_FAULT_FALLBACK; |
128ec037 KS |
791 | if (unlikely(anon_vma_prepare(vma))) |
792 | return VM_FAULT_OOM; | |
4fa6893f | 793 | khugepaged_enter_vma(vma, vma->vm_flags); |
d2081b2b | 794 | |
82b0f8c3 | 795 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 796 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
797 | transparent_hugepage_use_zero_page()) { |
798 | pgtable_t pgtable; | |
799 | struct page *zero_page; | |
2b740303 | 800 | vm_fault_t ret; |
4cf58924 | 801 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 802 | if (unlikely(!pgtable)) |
ba76149f | 803 | return VM_FAULT_OOM; |
6fcb52a5 | 804 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 805 | if (unlikely(!zero_page)) { |
bae473a4 | 806 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 807 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 808 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 809 | } |
82b0f8c3 | 810 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 811 | ret = 0; |
82b0f8c3 | 812 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
813 | ret = check_stable_address_space(vma->vm_mm); |
814 | if (ret) { | |
815 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 816 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 817 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 818 | spin_unlock(vmf->ptl); |
bfe8cc1d | 819 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 820 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
821 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
822 | } else { | |
bae473a4 | 823 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 824 | haddr, vmf->pmd, zero_page); |
fca40573 | 825 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 826 | spin_unlock(vmf->ptl); |
6b251fc9 | 827 | } |
bfe8cc1d | 828 | } else { |
82b0f8c3 | 829 | spin_unlock(vmf->ptl); |
bae473a4 | 830 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 831 | } |
6b251fc9 | 832 | return ret; |
71e3aac0 | 833 | } |
164cc4fe | 834 | gfp = vma_thp_gfp_mask(vma); |
cb196ee1 MWO |
835 | folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); |
836 | if (unlikely(!folio)) { | |
128ec037 | 837 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 838 | return VM_FAULT_FALLBACK; |
128ec037 | 839 | } |
cb196ee1 | 840 | return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); |
71e3aac0 AA |
841 | } |
842 | ||
ae18d6dc | 843 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
844 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
845 | pgtable_t pgtable) | |
5cad465d MW |
846 | { |
847 | struct mm_struct *mm = vma->vm_mm; | |
848 | pmd_t entry; | |
849 | spinlock_t *ptl; | |
850 | ||
851 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
852 | if (!pmd_none(*pmd)) { |
853 | if (write) { | |
854 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
855 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
856 | goto out_unlock; | |
857 | } | |
858 | entry = pmd_mkyoung(*pmd); | |
859 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
860 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
861 | update_mmu_cache_pmd(vma, addr, pmd); | |
862 | } | |
863 | ||
864 | goto out_unlock; | |
865 | } | |
866 | ||
f25748e3 DW |
867 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
868 | if (pfn_t_devmap(pfn)) | |
869 | entry = pmd_mkdevmap(entry); | |
01871e59 | 870 | if (write) { |
f55e1014 LT |
871 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
872 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 873 | } |
3b6521f5 OH |
874 | |
875 | if (pgtable) { | |
876 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 877 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 878 | pgtable = NULL; |
3b6521f5 OH |
879 | } |
880 | ||
01871e59 RZ |
881 | set_pmd_at(mm, addr, pmd, entry); |
882 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
883 | |
884 | out_unlock: | |
5cad465d | 885 | spin_unlock(ptl); |
c6f3c5ee AK |
886 | if (pgtable) |
887 | pte_free(mm, pgtable); | |
5cad465d MW |
888 | } |
889 | ||
9a9731b1 THV |
890 | /** |
891 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
892 | * @vmf: Structure describing the fault | |
893 | * @pfn: pfn to insert | |
894 | * @pgprot: page protection to use | |
895 | * @write: whether it's a write fault | |
896 | * | |
897 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
898 | * also consult the vmf_insert_mixed_prot() documentation when | |
899 | * @pgprot != @vmf->vma->vm_page_prot. | |
900 | * | |
901 | * Return: vm_fault_t value. | |
902 | */ | |
903 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
904 | pgprot_t pgprot, bool write) | |
5cad465d | 905 | { |
fce86ff5 DW |
906 | unsigned long addr = vmf->address & PMD_MASK; |
907 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 908 | pgtable_t pgtable = NULL; |
fce86ff5 | 909 | |
5cad465d MW |
910 | /* |
911 | * If we had pmd_special, we could avoid all these restrictions, | |
912 | * but we need to be consistent with PTEs and architectures that | |
913 | * can't support a 'special' bit. | |
914 | */ | |
e1fb4a08 DJ |
915 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
916 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
917 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
918 | (VM_PFNMAP|VM_MIXEDMAP)); | |
919 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
920 | |
921 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
922 | return VM_FAULT_SIGBUS; | |
308a047c | 923 | |
3b6521f5 | 924 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 925 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
926 | if (!pgtable) |
927 | return VM_FAULT_OOM; | |
928 | } | |
929 | ||
308a047c BP |
930 | track_pfn_insert(vma, &pgprot, pfn); |
931 | ||
fce86ff5 | 932 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 933 | return VM_FAULT_NOPAGE; |
5cad465d | 934 | } |
9a9731b1 | 935 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 936 | |
a00cc7d9 | 937 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 938 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 939 | { |
f55e1014 | 940 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
941 | pud = pud_mkwrite(pud); |
942 | return pud; | |
943 | } | |
944 | ||
945 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
946 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
947 | { | |
948 | struct mm_struct *mm = vma->vm_mm; | |
949 | pud_t entry; | |
950 | spinlock_t *ptl; | |
951 | ||
952 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
953 | if (!pud_none(*pud)) { |
954 | if (write) { | |
955 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
956 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
957 | goto out_unlock; | |
958 | } | |
959 | entry = pud_mkyoung(*pud); | |
960 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
961 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
962 | update_mmu_cache_pud(vma, addr, pud); | |
963 | } | |
964 | goto out_unlock; | |
965 | } | |
966 | ||
a00cc7d9 MW |
967 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
968 | if (pfn_t_devmap(pfn)) | |
969 | entry = pud_mkdevmap(entry); | |
970 | if (write) { | |
f55e1014 LT |
971 | entry = pud_mkyoung(pud_mkdirty(entry)); |
972 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
973 | } |
974 | set_pud_at(mm, addr, pud, entry); | |
975 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
976 | |
977 | out_unlock: | |
a00cc7d9 MW |
978 | spin_unlock(ptl); |
979 | } | |
980 | ||
9a9731b1 THV |
981 | /** |
982 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
983 | * @vmf: Structure describing the fault | |
984 | * @pfn: pfn to insert | |
985 | * @pgprot: page protection to use | |
986 | * @write: whether it's a write fault | |
987 | * | |
988 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
989 | * also consult the vmf_insert_mixed_prot() documentation when | |
990 | * @pgprot != @vmf->vma->vm_page_prot. | |
991 | * | |
992 | * Return: vm_fault_t value. | |
993 | */ | |
994 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
995 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 996 | { |
fce86ff5 DW |
997 | unsigned long addr = vmf->address & PUD_MASK; |
998 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 999 | |
a00cc7d9 MW |
1000 | /* |
1001 | * If we had pud_special, we could avoid all these restrictions, | |
1002 | * but we need to be consistent with PTEs and architectures that | |
1003 | * can't support a 'special' bit. | |
1004 | */ | |
62ec0d8c DJ |
1005 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
1006 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
1007 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
1008 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1009 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
1010 | |
1011 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1012 | return VM_FAULT_SIGBUS; | |
1013 | ||
1014 | track_pfn_insert(vma, &pgprot, pfn); | |
1015 | ||
fce86ff5 | 1016 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
1017 | return VM_FAULT_NOPAGE; |
1018 | } | |
9a9731b1 | 1019 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
1020 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
1021 | ||
3565fce3 | 1022 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a69e4717 | 1023 | pmd_t *pmd, bool write) |
3565fce3 DW |
1024 | { |
1025 | pmd_t _pmd; | |
1026 | ||
a8f97366 | 1027 | _pmd = pmd_mkyoung(*pmd); |
a69e4717 | 1028 | if (write) |
a8f97366 | 1029 | _pmd = pmd_mkdirty(_pmd); |
3565fce3 | 1030 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a69e4717 | 1031 | pmd, _pmd, write)) |
3565fce3 DW |
1032 | update_mmu_cache_pmd(vma, addr, pmd); |
1033 | } | |
1034 | ||
1035 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1036 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
1037 | { |
1038 | unsigned long pfn = pmd_pfn(*pmd); | |
1039 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 | 1040 | struct page *page; |
0f089235 | 1041 | int ret; |
3565fce3 DW |
1042 | |
1043 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
1044 | ||
f6f37321 | 1045 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
1046 | return NULL; |
1047 | ||
1048 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
1049 | /* pass */; | |
1050 | else | |
1051 | return NULL; | |
1052 | ||
1053 | if (flags & FOLL_TOUCH) | |
a69e4717 | 1054 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3565fce3 DW |
1055 | |
1056 | /* | |
1057 | * device mapped pages can only be returned if the | |
1058 | * caller will manage the page reference count. | |
1059 | */ | |
3faa52c0 | 1060 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1061 | return ERR_PTR(-EEXIST); |
1062 | ||
1063 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1064 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1065 | if (!*pgmap) | |
3565fce3 DW |
1066 | return ERR_PTR(-EFAULT); |
1067 | page = pfn_to_page(pfn); | |
0f089235 LG |
1068 | ret = try_grab_page(page, flags); |
1069 | if (ret) | |
1070 | page = ERR_PTR(ret); | |
3565fce3 DW |
1071 | |
1072 | return page; | |
1073 | } | |
1074 | ||
71e3aac0 AA |
1075 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1076 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
8f34f1ea | 1077 | struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) |
71e3aac0 | 1078 | { |
c4088ebd | 1079 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1080 | struct page *src_page; |
1081 | pmd_t pmd; | |
12c9d70b | 1082 | pgtable_t pgtable = NULL; |
628d47ce | 1083 | int ret = -ENOMEM; |
71e3aac0 | 1084 | |
628d47ce | 1085 | /* Skip if can be re-fill on fault */ |
8f34f1ea | 1086 | if (!vma_is_anonymous(dst_vma)) |
628d47ce KS |
1087 | return 0; |
1088 | ||
4cf58924 | 1089 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1090 | if (unlikely(!pgtable)) |
1091 | goto out; | |
71e3aac0 | 1092 | |
c4088ebd KS |
1093 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1094 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1095 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1096 | |
1097 | ret = -EAGAIN; | |
1098 | pmd = *src_pmd; | |
84c3fc4e ZY |
1099 | |
1100 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1101 | if (unlikely(is_swap_pmd(pmd))) { | |
1102 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1103 | ||
1104 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
6c287605 | 1105 | if (!is_readable_migration_entry(entry)) { |
4dd845b5 AP |
1106 | entry = make_readable_migration_entry( |
1107 | swp_offset(entry)); | |
84c3fc4e | 1108 | pmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1109 | if (pmd_swp_soft_dirty(*src_pmd)) |
1110 | pmd = pmd_swp_mksoft_dirty(pmd); | |
8f34f1ea PX |
1111 | if (pmd_swp_uffd_wp(*src_pmd)) |
1112 | pmd = pmd_swp_mkuffd_wp(pmd); | |
84c3fc4e ZY |
1113 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1114 | } | |
dd8a67f9 | 1115 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1116 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1117 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
8f34f1ea PX |
1118 | if (!userfaultfd_wp(dst_vma)) |
1119 | pmd = pmd_swp_clear_uffd_wp(pmd); | |
84c3fc4e ZY |
1120 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1121 | ret = 0; | |
1122 | goto out_unlock; | |
1123 | } | |
1124 | #endif | |
1125 | ||
628d47ce | 1126 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1127 | pte_free(dst_mm, pgtable); |
1128 | goto out_unlock; | |
1129 | } | |
fc9fe822 | 1130 | /* |
c4088ebd | 1131 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1132 | * under splitting since we don't split the page itself, only pmd to |
1133 | * a page table. | |
1134 | */ | |
1135 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 KS |
1136 | /* |
1137 | * get_huge_zero_page() will never allocate a new page here, | |
1138 | * since we already have a zero page to copy. It just takes a | |
1139 | * reference. | |
1140 | */ | |
5fc7a5f6 PX |
1141 | mm_get_huge_zero_page(dst_mm); |
1142 | goto out_zero_page; | |
fc9fe822 | 1143 | } |
de466bd6 | 1144 | |
628d47ce KS |
1145 | src_page = pmd_page(pmd); |
1146 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e | 1147 | |
fb3d824d DH |
1148 | get_page(src_page); |
1149 | if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { | |
1150 | /* Page maybe pinned: split and retry the fault on PTEs. */ | |
1151 | put_page(src_page); | |
d042035e PX |
1152 | pte_free(dst_mm, pgtable); |
1153 | spin_unlock(src_ptl); | |
1154 | spin_unlock(dst_ptl); | |
8f34f1ea | 1155 | __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); |
d042035e PX |
1156 | return -EAGAIN; |
1157 | } | |
628d47ce | 1158 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
5fc7a5f6 | 1159 | out_zero_page: |
c4812909 | 1160 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1161 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 1162 | pmdp_set_wrprotect(src_mm, addr, src_pmd); |
8f34f1ea PX |
1163 | if (!userfaultfd_wp(dst_vma)) |
1164 | pmd = pmd_clear_uffd_wp(pmd); | |
71e3aac0 AA |
1165 | pmd = pmd_mkold(pmd_wrprotect(pmd)); |
1166 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1167 | |
1168 | ret = 0; | |
1169 | out_unlock: | |
c4088ebd KS |
1170 | spin_unlock(src_ptl); |
1171 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1172 | out: |
1173 | return ret; | |
1174 | } | |
1175 | ||
a00cc7d9 MW |
1176 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1177 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
5fe653e9 | 1178 | pud_t *pud, bool write) |
a00cc7d9 MW |
1179 | { |
1180 | pud_t _pud; | |
1181 | ||
a8f97366 | 1182 | _pud = pud_mkyoung(*pud); |
5fe653e9 | 1183 | if (write) |
a8f97366 | 1184 | _pud = pud_mkdirty(_pud); |
a00cc7d9 | 1185 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
5fe653e9 | 1186 | pud, _pud, write)) |
a00cc7d9 MW |
1187 | update_mmu_cache_pud(vma, addr, pud); |
1188 | } | |
1189 | ||
1190 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1191 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1192 | { |
1193 | unsigned long pfn = pud_pfn(*pud); | |
1194 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 | 1195 | struct page *page; |
0f089235 | 1196 | int ret; |
a00cc7d9 MW |
1197 | |
1198 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1199 | ||
f6f37321 | 1200 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1201 | return NULL; |
1202 | ||
1203 | if (pud_present(*pud) && pud_devmap(*pud)) | |
1204 | /* pass */; | |
1205 | else | |
1206 | return NULL; | |
1207 | ||
1208 | if (flags & FOLL_TOUCH) | |
5fe653e9 | 1209 | touch_pud(vma, addr, pud, flags & FOLL_WRITE); |
a00cc7d9 MW |
1210 | |
1211 | /* | |
1212 | * device mapped pages can only be returned if the | |
1213 | * caller will manage the page reference count. | |
3faa52c0 JH |
1214 | * |
1215 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1216 | */ |
3faa52c0 | 1217 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1218 | return ERR_PTR(-EEXIST); |
1219 | ||
1220 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1221 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1222 | if (!*pgmap) | |
a00cc7d9 MW |
1223 | return ERR_PTR(-EFAULT); |
1224 | page = pfn_to_page(pfn); | |
0f089235 LG |
1225 | |
1226 | ret = try_grab_page(page, flags); | |
1227 | if (ret) | |
1228 | page = ERR_PTR(ret); | |
a00cc7d9 MW |
1229 | |
1230 | return page; | |
1231 | } | |
1232 | ||
1233 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1234 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1235 | struct vm_area_struct *vma) | |
1236 | { | |
1237 | spinlock_t *dst_ptl, *src_ptl; | |
1238 | pud_t pud; | |
1239 | int ret; | |
1240 | ||
1241 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1242 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1243 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1244 | ||
1245 | ret = -EAGAIN; | |
1246 | pud = *src_pud; | |
1247 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1248 | goto out_unlock; | |
1249 | ||
1250 | /* | |
1251 | * When page table lock is held, the huge zero pud should not be | |
1252 | * under splitting since we don't split the page itself, only pud to | |
1253 | * a page table. | |
1254 | */ | |
1255 | if (is_huge_zero_pud(pud)) { | |
1256 | /* No huge zero pud yet */ | |
1257 | } | |
1258 | ||
fb3d824d DH |
1259 | /* |
1260 | * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() | |
1261 | * and split if duplicating fails. | |
1262 | */ | |
a00cc7d9 MW |
1263 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1264 | pud = pud_mkold(pud_wrprotect(pud)); | |
1265 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1266 | ||
1267 | ret = 0; | |
1268 | out_unlock: | |
1269 | spin_unlock(src_ptl); | |
1270 | spin_unlock(dst_ptl); | |
1271 | return ret; | |
1272 | } | |
1273 | ||
1274 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1275 | { | |
a00cc7d9 MW |
1276 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
1277 | ||
1278 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1279 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1280 | goto unlock; | |
1281 | ||
5fe653e9 | 1282 | touch_pud(vmf->vma, vmf->address, vmf->pud, write); |
a00cc7d9 MW |
1283 | unlock: |
1284 | spin_unlock(vmf->ptl); | |
1285 | } | |
1286 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1287 | ||
5db4f15c | 1288 | void huge_pmd_set_accessed(struct vm_fault *vmf) |
a1dd450b | 1289 | { |
20f664aa | 1290 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1291 | |
82b0f8c3 | 1292 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
a69e4717 | 1293 | if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) |
a1dd450b WD |
1294 | goto unlock; |
1295 | ||
a69e4717 | 1296 | touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); |
a1dd450b WD |
1297 | |
1298 | unlock: | |
82b0f8c3 | 1299 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1300 | } |
1301 | ||
5db4f15c | 1302 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) |
71e3aac0 | 1303 | { |
c89357e2 | 1304 | const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; |
82b0f8c3 | 1305 | struct vm_area_struct *vma = vmf->vma; |
2fad3d14 | 1306 | struct folio *folio; |
3917c802 | 1307 | struct page *page; |
82b0f8c3 | 1308 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
5db4f15c | 1309 | pmd_t orig_pmd = vmf->orig_pmd; |
71e3aac0 | 1310 | |
82b0f8c3 | 1311 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1312 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1313 | |
93b4796d | 1314 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1315 | goto fallback; |
1316 | ||
82b0f8c3 | 1317 | spin_lock(vmf->ptl); |
3917c802 KS |
1318 | |
1319 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1320 | spin_unlock(vmf->ptl); | |
1321 | return 0; | |
1322 | } | |
71e3aac0 AA |
1323 | |
1324 | page = pmd_page(orig_pmd); | |
2fad3d14 | 1325 | folio = page_folio(page); |
f6004e73 | 1326 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 | 1327 | |
6c287605 DH |
1328 | /* Early check when only holding the PT lock. */ |
1329 | if (PageAnonExclusive(page)) | |
1330 | goto reuse; | |
1331 | ||
2fad3d14 MWO |
1332 | if (!folio_trylock(folio)) { |
1333 | folio_get(folio); | |
ba3c4ce6 | 1334 | spin_unlock(vmf->ptl); |
2fad3d14 | 1335 | folio_lock(folio); |
ba3c4ce6 HY |
1336 | spin_lock(vmf->ptl); |
1337 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1338 | spin_unlock(vmf->ptl); |
2fad3d14 MWO |
1339 | folio_unlock(folio); |
1340 | folio_put(folio); | |
3917c802 | 1341 | return 0; |
ba3c4ce6 | 1342 | } |
2fad3d14 | 1343 | folio_put(folio); |
ba3c4ce6 | 1344 | } |
3917c802 | 1345 | |
6c287605 DH |
1346 | /* Recheck after temporarily dropping the PT lock. */ |
1347 | if (PageAnonExclusive(page)) { | |
2fad3d14 | 1348 | folio_unlock(folio); |
6c287605 DH |
1349 | goto reuse; |
1350 | } | |
1351 | ||
3917c802 | 1352 | /* |
2fad3d14 MWO |
1353 | * See do_wp_page(): we can only reuse the folio exclusively if |
1354 | * there are no additional references. Note that we always drain | |
1355 | * the LRU pagevecs immediately after adding a THP. | |
3917c802 | 1356 | */ |
2fad3d14 MWO |
1357 | if (folio_ref_count(folio) > |
1358 | 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) | |
3bff7e3f | 1359 | goto unlock_fallback; |
2fad3d14 MWO |
1360 | if (folio_test_swapcache(folio)) |
1361 | folio_free_swap(folio); | |
1362 | if (folio_ref_count(folio) == 1) { | |
71e3aac0 | 1363 | pmd_t entry; |
6c54dc6c DH |
1364 | |
1365 | page_move_anon_rmap(page, vma); | |
2fad3d14 | 1366 | folio_unlock(folio); |
6c287605 | 1367 | reuse: |
c89357e2 DH |
1368 | if (unlikely(unshare)) { |
1369 | spin_unlock(vmf->ptl); | |
1370 | return 0; | |
1371 | } | |
71e3aac0 | 1372 | entry = pmd_mkyoung(orig_pmd); |
f55e1014 | 1373 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1374 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1375 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 1376 | spin_unlock(vmf->ptl); |
cb8d8633 | 1377 | return 0; |
71e3aac0 | 1378 | } |
3917c802 | 1379 | |
3bff7e3f | 1380 | unlock_fallback: |
2fad3d14 | 1381 | folio_unlock(folio); |
82b0f8c3 | 1382 | spin_unlock(vmf->ptl); |
3917c802 KS |
1383 | fallback: |
1384 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1385 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1386 | } |
1387 | ||
c27f479e DH |
1388 | static inline bool can_change_pmd_writable(struct vm_area_struct *vma, |
1389 | unsigned long addr, pmd_t pmd) | |
1390 | { | |
1391 | struct page *page; | |
1392 | ||
1393 | if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) | |
1394 | return false; | |
1395 | ||
1396 | /* Don't touch entries that are not even readable (NUMA hinting). */ | |
1397 | if (pmd_protnone(pmd)) | |
1398 | return false; | |
1399 | ||
1400 | /* Do we need write faults for softdirty tracking? */ | |
1401 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1402 | return false; | |
1403 | ||
1404 | /* Do we need write faults for uffd-wp tracking? */ | |
1405 | if (userfaultfd_huge_pmd_wp(vma, pmd)) | |
1406 | return false; | |
1407 | ||
1408 | if (!(vma->vm_flags & VM_SHARED)) { | |
1409 | /* See can_change_pte_writable(). */ | |
1410 | page = vm_normal_page_pmd(vma, addr, pmd); | |
1411 | return page && PageAnon(page) && PageAnonExclusive(page); | |
1412 | } | |
1413 | ||
1414 | /* See can_change_pte_writable(). */ | |
1415 | return pmd_dirty(pmd); | |
1416 | } | |
1417 | ||
5535be30 DH |
1418 | /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ |
1419 | static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, | |
1420 | struct vm_area_struct *vma, | |
1421 | unsigned int flags) | |
8310d48b | 1422 | { |
5535be30 DH |
1423 | /* If the pmd is writable, we can write to the page. */ |
1424 | if (pmd_write(pmd)) | |
1425 | return true; | |
1426 | ||
1427 | /* Maybe FOLL_FORCE is set to override it? */ | |
1428 | if (!(flags & FOLL_FORCE)) | |
1429 | return false; | |
1430 | ||
1431 | /* But FOLL_FORCE has no effect on shared mappings */ | |
1432 | if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) | |
1433 | return false; | |
1434 | ||
1435 | /* ... or read-only private ones */ | |
1436 | if (!(vma->vm_flags & VM_MAYWRITE)) | |
1437 | return false; | |
1438 | ||
1439 | /* ... or already writable ones that just need to take a write fault */ | |
1440 | if (vma->vm_flags & VM_WRITE) | |
1441 | return false; | |
1442 | ||
1443 | /* | |
1444 | * See can_change_pte_writable(): we broke COW and could map the page | |
1445 | * writable if we have an exclusive anonymous page ... | |
1446 | */ | |
1447 | if (!page || !PageAnon(page) || !PageAnonExclusive(page)) | |
1448 | return false; | |
1449 | ||
1450 | /* ... and a write-fault isn't required for other reasons. */ | |
1451 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1452 | return false; | |
1453 | return !userfaultfd_huge_pmd_wp(vma, pmd); | |
8310d48b KF |
1454 | } |
1455 | ||
b676b293 | 1456 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1457 | unsigned long addr, |
1458 | pmd_t *pmd, | |
1459 | unsigned int flags) | |
1460 | { | |
b676b293 | 1461 | struct mm_struct *mm = vma->vm_mm; |
5535be30 | 1462 | struct page *page; |
0f089235 | 1463 | int ret; |
71e3aac0 | 1464 | |
c4088ebd | 1465 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1466 | |
5535be30 DH |
1467 | page = pmd_page(*pmd); |
1468 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); | |
1469 | ||
1470 | if ((flags & FOLL_WRITE) && | |
1471 | !can_follow_write_pmd(*pmd, page, vma, flags)) | |
1472 | return NULL; | |
71e3aac0 | 1473 | |
85facf25 KS |
1474 | /* Avoid dumping huge zero page */ |
1475 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1476 | return ERR_PTR(-EFAULT); | |
1477 | ||
2b4847e7 | 1478 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
474098ed | 1479 | if (pmd_protnone(*pmd) && !gup_can_follow_protnone(flags)) |
5535be30 | 1480 | return NULL; |
3faa52c0 | 1481 | |
84209e87 | 1482 | if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) |
a7f22660 DH |
1483 | return ERR_PTR(-EMLINK); |
1484 | ||
b6a2619c DH |
1485 | VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && |
1486 | !PageAnonExclusive(page), page); | |
1487 | ||
0f089235 LG |
1488 | ret = try_grab_page(page, flags); |
1489 | if (ret) | |
1490 | return ERR_PTR(ret); | |
3faa52c0 | 1491 | |
3565fce3 | 1492 | if (flags & FOLL_TOUCH) |
a69e4717 | 1493 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3faa52c0 | 1494 | |
71e3aac0 | 1495 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1496 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1497 | |
71e3aac0 AA |
1498 | return page; |
1499 | } | |
1500 | ||
d10e63f2 | 1501 | /* NUMA hinting page fault entry point for trans huge pmds */ |
5db4f15c | 1502 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) |
d10e63f2 | 1503 | { |
82b0f8c3 | 1504 | struct vm_area_struct *vma = vmf->vma; |
c5b5a3dd YS |
1505 | pmd_t oldpmd = vmf->orig_pmd; |
1506 | pmd_t pmd; | |
b32967ff | 1507 | struct page *page; |
82b0f8c3 | 1508 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
c5b5a3dd | 1509 | int page_nid = NUMA_NO_NODE; |
33024536 | 1510 | int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); |
6a56ccbc | 1511 | bool migrated = false, writable = false; |
6688cc05 | 1512 | int flags = 0; |
d10e63f2 | 1513 | |
82b0f8c3 | 1514 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
c5b5a3dd | 1515 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { |
82b0f8c3 | 1516 | spin_unlock(vmf->ptl); |
de466bd6 MG |
1517 | goto out; |
1518 | } | |
1519 | ||
c5b5a3dd | 1520 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); |
6a56ccbc DH |
1521 | |
1522 | /* | |
1523 | * Detect now whether the PMD could be writable; this information | |
1524 | * is only valid while holding the PT lock. | |
1525 | */ | |
1526 | writable = pmd_write(pmd); | |
1527 | if (!writable && vma_wants_manual_pte_write_upgrade(vma) && | |
1528 | can_change_pmd_writable(vma, vmf->address, pmd)) | |
1529 | writable = true; | |
1530 | ||
c5b5a3dd YS |
1531 | page = vm_normal_page_pmd(vma, haddr, pmd); |
1532 | if (!page) | |
1533 | goto out_map; | |
1534 | ||
1535 | /* See similar comment in do_numa_page for explanation */ | |
6a56ccbc | 1536 | if (!writable) |
c5b5a3dd YS |
1537 | flags |= TNF_NO_GROUP; |
1538 | ||
1539 | page_nid = page_to_nid(page); | |
33024536 HY |
1540 | /* |
1541 | * For memory tiering mode, cpupid of slow memory page is used | |
1542 | * to record page access time. So use default value. | |
1543 | */ | |
1544 | if (node_is_toptier(page_nid)) | |
1545 | last_cpupid = page_cpupid_last(page); | |
c5b5a3dd YS |
1546 | target_nid = numa_migrate_prep(page, vma, haddr, page_nid, |
1547 | &flags); | |
1548 | ||
1549 | if (target_nid == NUMA_NO_NODE) { | |
1550 | put_page(page); | |
1551 | goto out_map; | |
1552 | } | |
1553 | ||
82b0f8c3 | 1554 | spin_unlock(vmf->ptl); |
6a56ccbc | 1555 | writable = false; |
8b1b436d | 1556 | |
c5b5a3dd | 1557 | migrated = migrate_misplaced_page(page, vma, target_nid); |
6688cc05 PZ |
1558 | if (migrated) { |
1559 | flags |= TNF_MIGRATED; | |
8191acbd | 1560 | page_nid = target_nid; |
c5b5a3dd | 1561 | } else { |
074c2381 | 1562 | flags |= TNF_MIGRATE_FAIL; |
c5b5a3dd YS |
1563 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1564 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { | |
1565 | spin_unlock(vmf->ptl); | |
1566 | goto out; | |
1567 | } | |
1568 | goto out_map; | |
1569 | } | |
b8916634 MG |
1570 | |
1571 | out: | |
98fa15f3 | 1572 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1573 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1574 | flags); |
8191acbd | 1575 | |
d10e63f2 | 1576 | return 0; |
c5b5a3dd YS |
1577 | |
1578 | out_map: | |
1579 | /* Restore the PMD */ | |
1580 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); | |
1581 | pmd = pmd_mkyoung(pmd); | |
6a56ccbc | 1582 | if (writable) |
c5b5a3dd YS |
1583 | pmd = pmd_mkwrite(pmd); |
1584 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); | |
1585 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
1586 | spin_unlock(vmf->ptl); | |
1587 | goto out; | |
d10e63f2 MG |
1588 | } |
1589 | ||
319904ad HY |
1590 | /* |
1591 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1592 | * Otherwise, return false. | |
1593 | */ | |
1594 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1595 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1596 | { |
1597 | spinlock_t *ptl; | |
1598 | pmd_t orig_pmd; | |
fc986a38 | 1599 | struct folio *folio; |
b8d3c4c3 | 1600 | struct mm_struct *mm = tlb->mm; |
319904ad | 1601 | bool ret = false; |
b8d3c4c3 | 1602 | |
ed6a7935 | 1603 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1604 | |
b6ec57f4 KS |
1605 | ptl = pmd_trans_huge_lock(pmd, vma); |
1606 | if (!ptl) | |
25eedabe | 1607 | goto out_unlocked; |
b8d3c4c3 MK |
1608 | |
1609 | orig_pmd = *pmd; | |
319904ad | 1610 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1611 | goto out; |
b8d3c4c3 | 1612 | |
84c3fc4e ZY |
1613 | if (unlikely(!pmd_present(orig_pmd))) { |
1614 | VM_BUG_ON(thp_migration_supported() && | |
1615 | !is_pmd_migration_entry(orig_pmd)); | |
1616 | goto out; | |
1617 | } | |
1618 | ||
fc986a38 | 1619 | folio = pfn_folio(pmd_pfn(orig_pmd)); |
b8d3c4c3 | 1620 | /* |
fc986a38 KW |
1621 | * If other processes are mapping this folio, we couldn't discard |
1622 | * the folio unless they all do MADV_FREE so let's skip the folio. | |
b8d3c4c3 | 1623 | */ |
fc986a38 | 1624 | if (folio_mapcount(folio) != 1) |
b8d3c4c3 MK |
1625 | goto out; |
1626 | ||
fc986a38 | 1627 | if (!folio_trylock(folio)) |
b8d3c4c3 MK |
1628 | goto out; |
1629 | ||
1630 | /* | |
1631 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1632 | * will deactivate only them. | |
1633 | */ | |
1634 | if (next - addr != HPAGE_PMD_SIZE) { | |
fc986a38 | 1635 | folio_get(folio); |
b8d3c4c3 | 1636 | spin_unlock(ptl); |
fc986a38 KW |
1637 | split_folio(folio); |
1638 | folio_unlock(folio); | |
1639 | folio_put(folio); | |
b8d3c4c3 MK |
1640 | goto out_unlocked; |
1641 | } | |
1642 | ||
fc986a38 KW |
1643 | if (folio_test_dirty(folio)) |
1644 | folio_clear_dirty(folio); | |
1645 | folio_unlock(folio); | |
b8d3c4c3 | 1646 | |
b8d3c4c3 | 1647 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1648 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1649 | orig_pmd = pmd_mkold(orig_pmd); |
1650 | orig_pmd = pmd_mkclean(orig_pmd); | |
1651 | ||
1652 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1653 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1654 | } | |
802a3a92 | 1655 | |
6a6fe9eb | 1656 | folio_mark_lazyfree(folio); |
319904ad | 1657 | ret = true; |
b8d3c4c3 MK |
1658 | out: |
1659 | spin_unlock(ptl); | |
1660 | out_unlocked: | |
1661 | return ret; | |
1662 | } | |
1663 | ||
953c66c2 AK |
1664 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1665 | { | |
1666 | pgtable_t pgtable; | |
1667 | ||
1668 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1669 | pte_free(mm, pgtable); | |
c4812909 | 1670 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1671 | } |
1672 | ||
71e3aac0 | 1673 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1674 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1675 | { |
da146769 | 1676 | pmd_t orig_pmd; |
bf929152 | 1677 | spinlock_t *ptl; |
71e3aac0 | 1678 | |
ed6a7935 | 1679 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1680 | |
b6ec57f4 KS |
1681 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1682 | if (!ptl) | |
da146769 KS |
1683 | return 0; |
1684 | /* | |
1685 | * For architectures like ppc64 we look at deposited pgtable | |
1686 | * when calling pmdp_huge_get_and_clear. So do the | |
1687 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1688 | * operations. | |
1689 | */ | |
93a98695 AK |
1690 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1691 | tlb->fullmm); | |
da146769 | 1692 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1693 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1694 | if (arch_needs_pgtable_deposit()) |
1695 | zap_deposited_table(tlb->mm, pmd); | |
da146769 | 1696 | spin_unlock(ptl); |
da146769 | 1697 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1698 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1699 | spin_unlock(ptl); |
da146769 | 1700 | } else { |
616b8371 ZY |
1701 | struct page *page = NULL; |
1702 | int flush_needed = 1; | |
1703 | ||
1704 | if (pmd_present(orig_pmd)) { | |
1705 | page = pmd_page(orig_pmd); | |
cea86fe2 | 1706 | page_remove_rmap(page, vma, true); |
616b8371 ZY |
1707 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
1708 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1709 | } else if (thp_migration_supported()) { | |
1710 | swp_entry_t entry; | |
1711 | ||
1712 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1713 | entry = pmd_to_swp_entry(orig_pmd); | |
af5cdaf8 | 1714 | page = pfn_swap_entry_to_page(entry); |
616b8371 ZY |
1715 | flush_needed = 0; |
1716 | } else | |
1717 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1718 | ||
b5072380 | 1719 | if (PageAnon(page)) { |
c14a6eb4 | 1720 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1721 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1722 | } else { | |
953c66c2 AK |
1723 | if (arch_needs_pgtable_deposit()) |
1724 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1725 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1726 | } |
616b8371 | 1727 | |
da146769 | 1728 | spin_unlock(ptl); |
616b8371 ZY |
1729 | if (flush_needed) |
1730 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1731 | } |
da146769 | 1732 | return 1; |
71e3aac0 AA |
1733 | } |
1734 | ||
1dd38b6c AK |
1735 | #ifndef pmd_move_must_withdraw |
1736 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1737 | spinlock_t *old_pmd_ptl, | |
1738 | struct vm_area_struct *vma) | |
1739 | { | |
1740 | /* | |
1741 | * With split pmd lock we also need to move preallocated | |
1742 | * PTE page table if new_pmd is on different PMD page table. | |
1743 | * | |
1744 | * We also don't deposit and withdraw tables for file pages. | |
1745 | */ | |
1746 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1747 | } | |
1748 | #endif | |
1749 | ||
ab6e3d09 NH |
1750 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1751 | { | |
1752 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1753 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1754 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1755 | else if (pmd_present(pmd)) | |
1756 | pmd = pmd_mksoft_dirty(pmd); | |
1757 | #endif | |
1758 | return pmd; | |
1759 | } | |
1760 | ||
bf8616d5 | 1761 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1762 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1763 | { |
bf929152 | 1764 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1765 | pmd_t pmd; |
37a1c49a | 1766 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1767 | bool force_flush = false; |
37a1c49a | 1768 | |
37a1c49a AA |
1769 | /* |
1770 | * The destination pmd shouldn't be established, free_pgtables() | |
1771 | * should have release it. | |
1772 | */ | |
1773 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1774 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1775 | return false; |
37a1c49a AA |
1776 | } |
1777 | ||
bf929152 KS |
1778 | /* |
1779 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1780 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1781 | */ |
b6ec57f4 KS |
1782 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1783 | if (old_ptl) { | |
bf929152 KS |
1784 | new_ptl = pmd_lockptr(mm, new_pmd); |
1785 | if (new_ptl != old_ptl) | |
1786 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1787 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1788 | if (pmd_present(pmd)) |
a2ce2666 | 1789 | force_flush = true; |
025c5b24 | 1790 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1791 | |
1dd38b6c | 1792 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1793 | pgtable_t pgtable; |
3592806c KS |
1794 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1795 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1796 | } |
ab6e3d09 NH |
1797 | pmd = move_soft_dirty_pmd(pmd); |
1798 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 | 1799 | if (force_flush) |
7c38f181 | 1800 | flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); |
eb66ae03 LT |
1801 | if (new_ptl != old_ptl) |
1802 | spin_unlock(new_ptl); | |
bf929152 | 1803 | spin_unlock(old_ptl); |
4b471e88 | 1804 | return true; |
37a1c49a | 1805 | } |
4b471e88 | 1806 | return false; |
37a1c49a AA |
1807 | } |
1808 | ||
f123d74a MG |
1809 | /* |
1810 | * Returns | |
1811 | * - 0 if PMD could not be locked | |
f0953a1b | 1812 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
e346e668 | 1813 | * or if prot_numa but THP migration is not supported |
f0953a1b | 1814 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary |
f123d74a | 1815 | */ |
4a18419f NA |
1816 | int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
1817 | pmd_t *pmd, unsigned long addr, pgprot_t newprot, | |
1818 | unsigned long cp_flags) | |
cd7548ab JW |
1819 | { |
1820 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1821 | spinlock_t *ptl; |
c9fe6656 | 1822 | pmd_t oldpmd, entry; |
58705444 | 1823 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1824 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1825 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
6a56ccbc | 1826 | int ret = 1; |
cd7548ab | 1827 | |
4a18419f NA |
1828 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
1829 | ||
e346e668 YS |
1830 | if (prot_numa && !thp_migration_supported()) |
1831 | return 1; | |
1832 | ||
b6ec57f4 | 1833 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1834 | if (!ptl) |
1835 | return 0; | |
e944fd67 | 1836 | |
84c3fc4e ZY |
1837 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1838 | if (is_swap_pmd(*pmd)) { | |
1839 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
6c287605 | 1840 | struct page *page = pfn_swap_entry_to_page(entry); |
84c3fc4e ZY |
1841 | |
1842 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
4dd845b5 | 1843 | if (is_writable_migration_entry(entry)) { |
84c3fc4e ZY |
1844 | pmd_t newpmd; |
1845 | /* | |
1846 | * A protection check is difficult so | |
1847 | * just be safe and disable write | |
1848 | */ | |
6c287605 DH |
1849 | if (PageAnon(page)) |
1850 | entry = make_readable_exclusive_migration_entry(swp_offset(entry)); | |
1851 | else | |
1852 | entry = make_readable_migration_entry(swp_offset(entry)); | |
84c3fc4e | 1853 | newpmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1854 | if (pmd_swp_soft_dirty(*pmd)) |
1855 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
8f34f1ea PX |
1856 | if (pmd_swp_uffd_wp(*pmd)) |
1857 | newpmd = pmd_swp_mkuffd_wp(newpmd); | |
84c3fc4e ZY |
1858 | set_pmd_at(mm, addr, pmd, newpmd); |
1859 | } | |
1860 | goto unlock; | |
1861 | } | |
1862 | #endif | |
1863 | ||
a1a3a2fc HY |
1864 | if (prot_numa) { |
1865 | struct page *page; | |
33024536 | 1866 | bool toptier; |
a1a3a2fc HY |
1867 | /* |
1868 | * Avoid trapping faults against the zero page. The read-only | |
1869 | * data is likely to be read-cached on the local CPU and | |
1870 | * local/remote hits to the zero page are not interesting. | |
1871 | */ | |
1872 | if (is_huge_zero_pmd(*pmd)) | |
1873 | goto unlock; | |
025c5b24 | 1874 | |
a1a3a2fc HY |
1875 | if (pmd_protnone(*pmd)) |
1876 | goto unlock; | |
0a85e51d | 1877 | |
a1a3a2fc | 1878 | page = pmd_page(*pmd); |
33024536 | 1879 | toptier = node_is_toptier(page_to_nid(page)); |
a1a3a2fc HY |
1880 | /* |
1881 | * Skip scanning top tier node if normal numa | |
1882 | * balancing is disabled | |
1883 | */ | |
1884 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
33024536 | 1885 | toptier) |
a1a3a2fc | 1886 | goto unlock; |
33024536 HY |
1887 | |
1888 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && | |
1889 | !toptier) | |
1890 | xchg_page_access_time(page, jiffies_to_msecs(jiffies)); | |
a1a3a2fc | 1891 | } |
ced10803 | 1892 | /* |
3e4e28c5 | 1893 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1894 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1895 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1896 | * |
1897 | * CPU0: CPU1: | |
1898 | * change_huge_pmd(prot_numa=1) | |
1899 | * pmdp_huge_get_and_clear_notify() | |
1900 | * madvise_dontneed() | |
1901 | * zap_pmd_range() | |
1902 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1903 | * // skip the pmd | |
1904 | * set_pmd_at(); | |
1905 | * // pmd is re-established | |
1906 | * | |
1907 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1908 | * which may break userspace. | |
1909 | * | |
4f831457 | 1910 | * pmdp_invalidate_ad() is required to make sure we don't miss |
ced10803 KS |
1911 | * dirty/young flags set by hardware. |
1912 | */ | |
4f831457 | 1913 | oldpmd = pmdp_invalidate_ad(vma, addr, pmd); |
ced10803 | 1914 | |
c9fe6656 | 1915 | entry = pmd_modify(oldpmd, newprot); |
f1eb1bac | 1916 | if (uffd_wp) |
292924b2 | 1917 | entry = pmd_mkuffd_wp(entry); |
f1eb1bac | 1918 | else if (uffd_wp_resolve) |
292924b2 PX |
1919 | /* |
1920 | * Leave the write bit to be handled by PF interrupt | |
1921 | * handler, then things like COW could be properly | |
1922 | * handled. | |
1923 | */ | |
1924 | entry = pmd_clear_uffd_wp(entry); | |
c27f479e DH |
1925 | |
1926 | /* See change_pte_range(). */ | |
1927 | if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && | |
1928 | can_change_pmd_writable(vma, addr, entry)) | |
1929 | entry = pmd_mkwrite(entry); | |
1930 | ||
0a85e51d KS |
1931 | ret = HPAGE_PMD_NR; |
1932 | set_pmd_at(mm, addr, pmd, entry); | |
4a18419f | 1933 | |
c9fe6656 NA |
1934 | if (huge_pmd_needs_flush(oldpmd, entry)) |
1935 | tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); | |
0a85e51d KS |
1936 | unlock: |
1937 | spin_unlock(ptl); | |
025c5b24 NH |
1938 | return ret; |
1939 | } | |
1940 | ||
1941 | /* | |
8f19b0c0 | 1942 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1943 | * |
8f19b0c0 HY |
1944 | * Note that if it returns page table lock pointer, this routine returns without |
1945 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1946 | */ |
b6ec57f4 | 1947 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1948 | { |
b6ec57f4 KS |
1949 | spinlock_t *ptl; |
1950 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1951 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1952 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1953 | return ptl; |
1954 | spin_unlock(ptl); | |
1955 | return NULL; | |
cd7548ab JW |
1956 | } |
1957 | ||
a00cc7d9 | 1958 | /* |
d965e390 | 1959 | * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. |
a00cc7d9 | 1960 | * |
d965e390 ML |
1961 | * Note that if it returns page table lock pointer, this routine returns without |
1962 | * unlocking page table lock. So callers must unlock it. | |
a00cc7d9 MW |
1963 | */ |
1964 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1965 | { | |
1966 | spinlock_t *ptl; | |
1967 | ||
1968 | ptl = pud_lock(vma->vm_mm, pud); | |
1969 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1970 | return ptl; | |
1971 | spin_unlock(ptl); | |
1972 | return NULL; | |
1973 | } | |
1974 | ||
1975 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1976 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1977 | pud_t *pud, unsigned long addr) | |
1978 | { | |
a00cc7d9 MW |
1979 | spinlock_t *ptl; |
1980 | ||
1981 | ptl = __pud_trans_huge_lock(pud, vma); | |
1982 | if (!ptl) | |
1983 | return 0; | |
74929079 | 1984 | |
70516b93 | 1985 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1986 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1987 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1988 | spin_unlock(ptl); |
1989 | /* No zero page support yet */ | |
1990 | } else { | |
1991 | /* No support for anonymous PUD pages yet */ | |
1992 | BUG(); | |
1993 | } | |
1994 | return 1; | |
1995 | } | |
1996 | ||
1997 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
1998 | unsigned long haddr) | |
1999 | { | |
2000 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2001 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2002 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2003 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2004 | ||
ce9311cf | 2005 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2006 | |
2007 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2008 | } | |
2009 | ||
2010 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2011 | unsigned long address) | |
2012 | { | |
2013 | spinlock_t *ptl; | |
ac46d4f3 | 2014 | struct mmu_notifier_range range; |
a00cc7d9 | 2015 | |
7d4a8be0 | 2016 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, |
6f4f13e8 | 2017 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2018 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2019 | mmu_notifier_invalidate_range_start(&range); | |
2020 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2021 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2022 | goto out; | |
ac46d4f3 | 2023 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2024 | |
2025 | out: | |
2026 | spin_unlock(ptl); | |
4645b9fe JG |
2027 | /* |
2028 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2029 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2030 | */ | |
ac46d4f3 | 2031 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2032 | } |
2033 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2034 | ||
eef1b3ba KS |
2035 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2036 | unsigned long haddr, pmd_t *pmd) | |
2037 | { | |
2038 | struct mm_struct *mm = vma->vm_mm; | |
2039 | pgtable_t pgtable; | |
2040 | pmd_t _pmd; | |
2041 | int i; | |
2042 | ||
0f10851e JG |
2043 | /* |
2044 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2045 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2046 | * replacing a zero pmd write protected page with a zero pte write | |
2047 | * protected page. | |
2048 | * | |
ee65728e | 2049 | * See Documentation/mm/mmu_notifier.rst |
0f10851e JG |
2050 | */ |
2051 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2052 | |
2053 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2054 | pmd_populate(mm, &_pmd, pgtable); | |
2055 | ||
2056 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2057 | pte_t *pte, entry; | |
2058 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2059 | entry = pte_mkspecial(entry); | |
2060 | pte = pte_offset_map(&_pmd, haddr); | |
2061 | VM_BUG_ON(!pte_none(*pte)); | |
2062 | set_pte_at(mm, haddr, pte, entry); | |
2063 | pte_unmap(pte); | |
2064 | } | |
2065 | smp_wmb(); /* make pte visible before pmd */ | |
2066 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2067 | } |
2068 | ||
2069 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2070 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2071 | { |
2072 | struct mm_struct *mm = vma->vm_mm; | |
2073 | struct page *page; | |
2074 | pgtable_t pgtable; | |
423ac9af | 2075 | pmd_t old_pmd, _pmd; |
292924b2 | 2076 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
0ccf7f16 | 2077 | bool anon_exclusive = false, dirty = false; |
2ac015e2 | 2078 | unsigned long addr; |
eef1b3ba KS |
2079 | int i; |
2080 | ||
2081 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2082 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2083 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2084 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2085 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2086 | |
2087 | count_vm_event(THP_SPLIT_PMD); | |
2088 | ||
d21b9e57 | 2089 | if (!vma_is_anonymous(vma)) { |
99fa8a48 | 2090 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
2091 | /* |
2092 | * We are going to unmap this huge page. So | |
2093 | * just go ahead and zap it | |
2094 | */ | |
2095 | if (arch_needs_pgtable_deposit()) | |
2096 | zap_deposited_table(mm, pmd); | |
2484ca9b | 2097 | if (vma_is_special_huge(vma)) |
d21b9e57 | 2098 | return; |
99fa8a48 HD |
2099 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
2100 | swp_entry_t entry; | |
2101 | ||
2102 | entry = pmd_to_swp_entry(old_pmd); | |
af5cdaf8 | 2103 | page = pfn_swap_entry_to_page(entry); |
99fa8a48 HD |
2104 | } else { |
2105 | page = pmd_page(old_pmd); | |
2106 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2107 | set_page_dirty(page); | |
2108 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2109 | SetPageReferenced(page); | |
cea86fe2 | 2110 | page_remove_rmap(page, vma, true); |
99fa8a48 HD |
2111 | put_page(page); |
2112 | } | |
fadae295 | 2113 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2114 | return; |
99fa8a48 HD |
2115 | } |
2116 | ||
3b77e8c8 | 2117 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2118 | /* |
2119 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2120 | * mmu_notifier_invalidate_range() see comments below inside | |
2121 | * __split_huge_pmd() ? | |
2122 | * | |
2123 | * We are going from a zero huge page write protected to zero | |
2124 | * small page also write protected so it does not seems useful | |
2125 | * to invalidate secondary mmu at this time. | |
2126 | */ | |
eef1b3ba KS |
2127 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2128 | } | |
2129 | ||
423ac9af AK |
2130 | /* |
2131 | * Up to this point the pmd is present and huge and userland has the | |
2132 | * whole access to the hugepage during the split (which happens in | |
2133 | * place). If we overwrite the pmd with the not-huge version pointing | |
2134 | * to the pte here (which of course we could if all CPUs were bug | |
2135 | * free), userland could trigger a small page size TLB miss on the | |
2136 | * small sized TLB while the hugepage TLB entry is still established in | |
2137 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2138 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2139 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2140 | * only safe if the permission and cache attributes of the two entries |
2141 | * loaded in the two TLB is identical (which should be the case here). | |
2142 | * But it is generally safer to never allow small and huge TLB entries | |
2143 | * for the same virtual address to be loaded simultaneously. So instead | |
2144 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2145 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2146 | * must remain set at all times on the pmd until the split is complete | |
2147 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2148 | * non-huge version of the pmd entry with pmd_populate. | |
2149 | */ | |
2150 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2151 | ||
423ac9af | 2152 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2153 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2154 | swp_entry_t entry; |
2155 | ||
423ac9af | 2156 | entry = pmd_to_swp_entry(old_pmd); |
af5cdaf8 | 2157 | page = pfn_swap_entry_to_page(entry); |
4dd845b5 | 2158 | write = is_writable_migration_entry(entry); |
6c287605 DH |
2159 | if (PageAnon(page)) |
2160 | anon_exclusive = is_readable_exclusive_migration_entry(entry); | |
2e346877 PX |
2161 | young = is_migration_entry_young(entry); |
2162 | dirty = is_migration_entry_dirty(entry); | |
2e83ee1d | 2163 | soft_dirty = pmd_swp_soft_dirty(old_pmd); |
f45ec5ff | 2164 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2165 | } else { |
423ac9af | 2166 | page = pmd_page(old_pmd); |
0ccf7f16 PX |
2167 | if (pmd_dirty(old_pmd)) { |
2168 | dirty = true; | |
2e83ee1d | 2169 | SetPageDirty(page); |
0ccf7f16 | 2170 | } |
2e83ee1d PX |
2171 | write = pmd_write(old_pmd); |
2172 | young = pmd_young(old_pmd); | |
2173 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2174 | uffd_wp = pmd_uffd_wp(old_pmd); |
6c287605 | 2175 | |
9d84604b | 2176 | VM_BUG_ON_PAGE(!page_count(page), page); |
6c287605 DH |
2177 | |
2178 | /* | |
2179 | * Without "freeze", we'll simply split the PMD, propagating the | |
2180 | * PageAnonExclusive() flag for each PTE by setting it for | |
2181 | * each subpage -- no need to (temporarily) clear. | |
2182 | * | |
2183 | * With "freeze" we want to replace mapped pages by | |
2184 | * migration entries right away. This is only possible if we | |
2185 | * managed to clear PageAnonExclusive() -- see | |
2186 | * set_pmd_migration_entry(). | |
2187 | * | |
2188 | * In case we cannot clear PageAnonExclusive(), split the PMD | |
2189 | * only and let try_to_migrate_one() fail later. | |
088b8aa5 DH |
2190 | * |
2191 | * See page_try_share_anon_rmap(): invalidate PMD first. | |
6c287605 DH |
2192 | */ |
2193 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); | |
2194 | if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) | |
2195 | freeze = false; | |
96d82deb HD |
2196 | if (!freeze) |
2197 | page_ref_add(page, HPAGE_PMD_NR - 1); | |
2e83ee1d | 2198 | } |
eef1b3ba | 2199 | |
423ac9af AK |
2200 | /* |
2201 | * Withdraw the table only after we mark the pmd entry invalid. | |
2202 | * This's critical for some architectures (Power). | |
2203 | */ | |
eef1b3ba KS |
2204 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2205 | pmd_populate(mm, &_pmd, pgtable); | |
2206 | ||
2ac015e2 | 2207 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2208 | pte_t entry, *pte; |
2209 | /* | |
2210 | * Note that NUMA hinting access restrictions are not | |
2211 | * transferred to avoid any possibility of altering | |
2212 | * permissions across VMAs. | |
2213 | */ | |
84c3fc4e | 2214 | if (freeze || pmd_migration) { |
ba988280 | 2215 | swp_entry_t swp_entry; |
4dd845b5 AP |
2216 | if (write) |
2217 | swp_entry = make_writable_migration_entry( | |
2218 | page_to_pfn(page + i)); | |
6c287605 DH |
2219 | else if (anon_exclusive) |
2220 | swp_entry = make_readable_exclusive_migration_entry( | |
2221 | page_to_pfn(page + i)); | |
4dd845b5 AP |
2222 | else |
2223 | swp_entry = make_readable_migration_entry( | |
2224 | page_to_pfn(page + i)); | |
2e346877 PX |
2225 | if (young) |
2226 | swp_entry = make_migration_entry_young(swp_entry); | |
2227 | if (dirty) | |
2228 | swp_entry = make_migration_entry_dirty(swp_entry); | |
ba988280 | 2229 | entry = swp_entry_to_pte(swp_entry); |
804dd150 AA |
2230 | if (soft_dirty) |
2231 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2232 | if (uffd_wp) |
2233 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2234 | } else { |
6d2329f8 | 2235 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2236 | entry = maybe_mkwrite(entry, vma); |
6c287605 DH |
2237 | if (anon_exclusive) |
2238 | SetPageAnonExclusive(page + i); | |
ba988280 KS |
2239 | if (!young) |
2240 | entry = pte_mkold(entry); | |
e833bc50 PX |
2241 | /* NOTE: this may set soft-dirty too on some archs */ |
2242 | if (dirty) | |
2243 | entry = pte_mkdirty(entry); | |
624a2c94 | 2244 | /* |
e833bc50 PX |
2245 | * NOTE: this needs to happen after pte_mkdirty, |
2246 | * because some archs (sparc64, loongarch) could | |
2247 | * set hw write bit when mkdirty. | |
624a2c94 | 2248 | */ |
e833bc50 PX |
2249 | if (!write) |
2250 | entry = pte_wrprotect(entry); | |
804dd150 AA |
2251 | if (soft_dirty) |
2252 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2253 | if (uffd_wp) |
2254 | entry = pte_mkuffd_wp(entry); | |
96d82deb | 2255 | page_add_anon_rmap(page + i, vma, addr, false); |
ba988280 | 2256 | } |
2ac015e2 | 2257 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2258 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2259 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2260 | pte_unmap(pte); |
eef1b3ba KS |
2261 | } |
2262 | ||
cb67f428 HD |
2263 | if (!pmd_migration) |
2264 | page_remove_rmap(page, vma, true); | |
96d82deb HD |
2265 | if (freeze) |
2266 | put_page(page); | |
eef1b3ba KS |
2267 | |
2268 | smp_wmb(); /* make pte visible before pmd */ | |
2269 | pmd_populate(mm, pmd, pgtable); | |
2270 | } | |
2271 | ||
2272 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
af28a988 | 2273 | unsigned long address, bool freeze, struct folio *folio) |
eef1b3ba KS |
2274 | { |
2275 | spinlock_t *ptl; | |
ac46d4f3 | 2276 | struct mmu_notifier_range range; |
eef1b3ba | 2277 | |
7d4a8be0 | 2278 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, |
6f4f13e8 | 2279 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2280 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2281 | mmu_notifier_invalidate_range_start(&range); | |
2282 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2283 | |
2284 | /* | |
af28a988 MWO |
2285 | * If caller asks to setup a migration entry, we need a folio to check |
2286 | * pmd against. Otherwise we can end up replacing wrong folio. | |
33f4751e | 2287 | */ |
af28a988 | 2288 | VM_BUG_ON(freeze && !folio); |
83a8441f | 2289 | VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); |
33f4751e | 2290 | |
7f760917 | 2291 | if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || |
83a8441f | 2292 | is_pmd_migration_entry(*pmd)) { |
cea33328 ML |
2293 | /* |
2294 | * It's safe to call pmd_page when folio is set because it's | |
2295 | * guaranteed that pmd is present. | |
2296 | */ | |
83a8441f MWO |
2297 | if (folio && folio != page_folio(pmd_page(*pmd))) |
2298 | goto out; | |
7f760917 | 2299 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
83a8441f | 2300 | } |
7f760917 | 2301 | |
e90309c9 | 2302 | out: |
eef1b3ba | 2303 | spin_unlock(ptl); |
4645b9fe JG |
2304 | /* |
2305 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2306 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2307 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2308 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2309 | * fault will trigger a flush_notify before pointing to a new page | |
2310 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2311 | * page in the meantime) | |
2312 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2313 | * to invalidate secondary tlb entry they are all still valid. | |
2314 | * any further changes to individual pte will notify. So no need | |
2315 | * to call mmu_notifier->invalidate_range() | |
2316 | */ | |
ac46d4f3 | 2317 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2318 | } |
2319 | ||
fec89c10 | 2320 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
af28a988 | 2321 | bool freeze, struct folio *folio) |
94fcc585 | 2322 | { |
50722804 | 2323 | pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); |
94fcc585 | 2324 | |
50722804 | 2325 | if (!pmd) |
f72e7dcd HD |
2326 | return; |
2327 | ||
af28a988 | 2328 | __split_huge_pmd(vma, pmd, address, freeze, folio); |
94fcc585 AA |
2329 | } |
2330 | ||
71f9e58e ML |
2331 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2332 | { | |
2333 | /* | |
2334 | * If the new address isn't hpage aligned and it could previously | |
2335 | * contain an hugepage: check if we need to split an huge pmd. | |
2336 | */ | |
2337 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2338 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2339 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2340 | split_huge_pmd_address(vma, address, false, NULL); | |
2341 | } | |
2342 | ||
e1b9996b | 2343 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2344 | unsigned long start, |
2345 | unsigned long end, | |
2346 | long adjust_next) | |
2347 | { | |
71f9e58e ML |
2348 | /* Check if we need to split start first. */ |
2349 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2350 | |
71f9e58e ML |
2351 | /* Check if we need to split end next. */ |
2352 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2353 | |
2354 | /* | |
68540502 | 2355 | * If we're also updating the next vma vm_start, |
71f9e58e | 2356 | * check if we need to split it. |
94fcc585 AA |
2357 | */ |
2358 | if (adjust_next > 0) { | |
68540502 | 2359 | struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); |
94fcc585 | 2360 | unsigned long nstart = next->vm_start; |
f9d86a60 | 2361 | nstart += adjust_next; |
71f9e58e | 2362 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2363 | } |
2364 | } | |
e9b61f19 | 2365 | |
684555aa | 2366 | static void unmap_folio(struct folio *folio) |
e9b61f19 | 2367 | { |
a98a2f0c AP |
2368 | enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | |
2369 | TTU_SYNC; | |
e9b61f19 | 2370 | |
684555aa | 2371 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); |
e9b61f19 | 2372 | |
a98a2f0c AP |
2373 | /* |
2374 | * Anon pages need migration entries to preserve them, but file | |
2375 | * pages can simply be left unmapped, then faulted back on demand. | |
2376 | * If that is ever changed (perhaps for mlock), update remap_page(). | |
2377 | */ | |
4b8554c5 MWO |
2378 | if (folio_test_anon(folio)) |
2379 | try_to_migrate(folio, ttu_flags); | |
a98a2f0c | 2380 | else |
869f7ee6 | 2381 | try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); |
e9b61f19 KS |
2382 | } |
2383 | ||
4eecb8b9 | 2384 | static void remap_page(struct folio *folio, unsigned long nr) |
e9b61f19 | 2385 | { |
4eecb8b9 | 2386 | int i = 0; |
ab02c252 | 2387 | |
684555aa | 2388 | /* If unmap_folio() uses try_to_migrate() on file, remove this check */ |
4eecb8b9 | 2389 | if (!folio_test_anon(folio)) |
ab02c252 | 2390 | return; |
4eecb8b9 MWO |
2391 | for (;;) { |
2392 | remove_migration_ptes(folio, folio, true); | |
2393 | i += folio_nr_pages(folio); | |
2394 | if (i >= nr) | |
2395 | break; | |
2396 | folio = folio_next(folio); | |
ace71a19 | 2397 | } |
e9b61f19 KS |
2398 | } |
2399 | ||
94866635 | 2400 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2401 | struct lruvec *lruvec, struct list_head *list) |
2402 | { | |
94866635 AS |
2403 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2404 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2405 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2406 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2407 | |
6dbb5741 | 2408 | if (list) { |
88dcb9a3 | 2409 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2410 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2411 | get_page(tail); |
2412 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2413 | } else { |
6dbb5741 AS |
2414 | /* head is still on lru (and we have it frozen) */ |
2415 | VM_WARN_ON(!PageLRU(head)); | |
07ca7606 HD |
2416 | if (PageUnevictable(tail)) |
2417 | tail->mlock_count = 0; | |
2418 | else | |
2419 | list_add_tail(&tail->lru, &head->lru); | |
6dbb5741 | 2420 | SetPageLRU(tail); |
88dcb9a3 AS |
2421 | } |
2422 | } | |
2423 | ||
8df651c7 | 2424 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2425 | struct lruvec *lruvec, struct list_head *list) |
2426 | { | |
e9b61f19 KS |
2427 | struct page *page_tail = head + tail; |
2428 | ||
8df651c7 | 2429 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2430 | |
2431 | /* | |
605ca5ed KK |
2432 | * Clone page flags before unfreezing refcount. |
2433 | * | |
2434 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2435 | * for example lock_page() which set PG_waiters. |
6c287605 DH |
2436 | * |
2437 | * Note that for mapped sub-pages of an anonymous THP, | |
684555aa | 2438 | * PG_anon_exclusive has been cleared in unmap_folio() and is stored in |
6c287605 DH |
2439 | * the migration entry instead from where remap_page() will restore it. |
2440 | * We can still have PG_anon_exclusive set on effectively unmapped and | |
2441 | * unreferenced sub-pages of an anonymous THP: we can simply drop | |
2442 | * PG_anon_exclusive (-> PG_mappedtodisk) for these here. | |
e9b61f19 | 2443 | */ |
e9b61f19 KS |
2444 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2445 | page_tail->flags |= (head->flags & | |
2446 | ((1L << PG_referenced) | | |
2447 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2448 | (1L << PG_swapcache) | |
e9b61f19 KS |
2449 | (1L << PG_mlocked) | |
2450 | (1L << PG_uptodate) | | |
2451 | (1L << PG_active) | | |
1899ad18 | 2452 | (1L << PG_workingset) | |
e9b61f19 | 2453 | (1L << PG_locked) | |
b8d3c4c3 | 2454 | (1L << PG_unevictable) | |
b0284cd2 | 2455 | #ifdef CONFIG_ARCH_USES_PG_ARCH_X |
72e6afa0 | 2456 | (1L << PG_arch_2) | |
ef6458b1 | 2457 | (1L << PG_arch_3) | |
72e6afa0 | 2458 | #endif |
ec1c86b2 YZ |
2459 | (1L << PG_dirty) | |
2460 | LRU_GEN_MASK | LRU_REFS_MASK)); | |
e9b61f19 | 2461 | |
cb67f428 | 2462 | /* ->mapping in first and second tail page is replaced by other uses */ |
173d9d9f HD |
2463 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
2464 | page_tail); | |
2465 | page_tail->mapping = head->mapping; | |
2466 | page_tail->index = head->index + tail; | |
71e2d666 MG |
2467 | |
2468 | /* | |
2469 | * page->private should not be set in tail pages with the exception | |
2470 | * of swap cache pages that store the swp_entry_t in tail pages. | |
2471 | * Fix up and warn once if private is unexpectedly set. | |
cb67f428 | 2472 | * |
94688e8e | 2473 | * What of 32-bit systems, on which folio->_pincount overlays |
cb67f428 | 2474 | * head[1].private? No problem: THP_SWAP is not enabled on 32-bit, and |
94688e8e | 2475 | * pincount must be 0 for folio_ref_freeze() to have succeeded. |
71e2d666 MG |
2476 | */ |
2477 | if (!folio_test_swapcache(page_folio(head))) { | |
5aae9265 | 2478 | VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, page_tail); |
71e2d666 MG |
2479 | page_tail->private = 0; |
2480 | } | |
173d9d9f | 2481 | |
605ca5ed | 2482 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2483 | smp_wmb(); |
2484 | ||
605ca5ed KK |
2485 | /* |
2486 | * Clear PageTail before unfreezing page refcount. | |
2487 | * | |
2488 | * After successful get_page_unless_zero() might follow put_page() | |
2489 | * which needs correct compound_head(). | |
2490 | */ | |
e9b61f19 KS |
2491 | clear_compound_head(page_tail); |
2492 | ||
605ca5ed KK |
2493 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2494 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2495 | PageSwapCache(head))); | |
2496 | ||
e9b61f19 KS |
2497 | if (page_is_young(head)) |
2498 | set_page_young(page_tail); | |
2499 | if (page_is_idle(head)) | |
2500 | set_page_idle(page_tail); | |
2501 | ||
e9b61f19 | 2502 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2503 | |
2504 | /* | |
2505 | * always add to the tail because some iterators expect new | |
2506 | * pages to show after the currently processed elements - e.g. | |
2507 | * migrate_pages | |
2508 | */ | |
e9b61f19 | 2509 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2510 | } |
2511 | ||
baa355fd | 2512 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2513 | pgoff_t end) |
e9b61f19 | 2514 | { |
e809c3fe MWO |
2515 | struct folio *folio = page_folio(page); |
2516 | struct page *head = &folio->page; | |
e9b61f19 | 2517 | struct lruvec *lruvec; |
4101196b MWO |
2518 | struct address_space *swap_cache = NULL; |
2519 | unsigned long offset = 0; | |
8cce5475 | 2520 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2521 | int i; |
e9b61f19 | 2522 | |
e9b61f19 | 2523 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2524 | split_page_memcg(head, nr); |
e9b61f19 | 2525 | |
4101196b MWO |
2526 | if (PageAnon(head) && PageSwapCache(head)) { |
2527 | swp_entry_t entry = { .val = page_private(head) }; | |
2528 | ||
2529 | offset = swp_offset(entry); | |
2530 | swap_cache = swap_address_space(entry); | |
2531 | xa_lock(&swap_cache->i_pages); | |
2532 | } | |
2533 | ||
f0953a1b | 2534 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
e809c3fe | 2535 | lruvec = folio_lruvec_lock(folio); |
b6769834 | 2536 | |
eac96c3e YS |
2537 | ClearPageHasHWPoisoned(head); |
2538 | ||
8cce5475 | 2539 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2540 | __split_huge_page_tail(head, i, lruvec, list); |
d144bf62 | 2541 | /* Some pages can be beyond EOF: drop them from page cache */ |
baa355fd | 2542 | if (head[i].index >= end) { |
fb5c2029 MWO |
2543 | struct folio *tail = page_folio(head + i); |
2544 | ||
d144bf62 | 2545 | if (shmem_mapping(head->mapping)) |
800d8c63 | 2546 | shmem_uncharge(head->mapping->host, 1); |
fb5c2029 MWO |
2547 | else if (folio_test_clear_dirty(tail)) |
2548 | folio_account_cleaned(tail, | |
2549 | inode_to_wb(folio->mapping->host)); | |
2550 | __filemap_remove_folio(tail, NULL); | |
2551 | folio_put(tail); | |
4101196b MWO |
2552 | } else if (!PageAnon(page)) { |
2553 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2554 | head + i, 0); | |
2555 | } else if (swap_cache) { | |
2556 | __xa_store(&swap_cache->i_pages, offset + i, | |
2557 | head + i, 0); | |
baa355fd KS |
2558 | } |
2559 | } | |
e9b61f19 KS |
2560 | |
2561 | ClearPageCompound(head); | |
6168d0da | 2562 | unlock_page_lruvec(lruvec); |
b6769834 | 2563 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2564 | |
8cce5475 | 2565 | split_page_owner(head, nr); |
f7da677b | 2566 | |
baa355fd KS |
2567 | /* See comment in __split_huge_page_tail() */ |
2568 | if (PageAnon(head)) { | |
aa5dc07f | 2569 | /* Additional pin to swap cache */ |
4101196b | 2570 | if (PageSwapCache(head)) { |
38d8b4e6 | 2571 | page_ref_add(head, 2); |
4101196b MWO |
2572 | xa_unlock(&swap_cache->i_pages); |
2573 | } else { | |
38d8b4e6 | 2574 | page_ref_inc(head); |
4101196b | 2575 | } |
baa355fd | 2576 | } else { |
aa5dc07f | 2577 | /* Additional pin to page cache */ |
baa355fd | 2578 | page_ref_add(head, 2); |
b93b0163 | 2579 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2580 | } |
b6769834 | 2581 | local_irq_enable(); |
e9b61f19 | 2582 | |
4eecb8b9 | 2583 | remap_page(folio, nr); |
e9b61f19 | 2584 | |
c4f9c701 HY |
2585 | if (PageSwapCache(head)) { |
2586 | swp_entry_t entry = { .val = page_private(head) }; | |
2587 | ||
2588 | split_swap_cluster(entry); | |
2589 | } | |
2590 | ||
8cce5475 | 2591 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2592 | struct page *subpage = head + i; |
2593 | if (subpage == page) | |
2594 | continue; | |
2595 | unlock_page(subpage); | |
2596 | ||
2597 | /* | |
2598 | * Subpages may be freed if there wasn't any mapping | |
2599 | * like if add_to_swap() is running on a lru page that | |
2600 | * had its mapping zapped. And freeing these pages | |
2601 | * requires taking the lru_lock so we do the put_page | |
2602 | * of the tail pages after the split is complete. | |
2603 | */ | |
0b175468 | 2604 | free_page_and_swap_cache(subpage); |
e9b61f19 KS |
2605 | } |
2606 | } | |
2607 | ||
b8f593cd | 2608 | /* Racy check whether the huge page can be split */ |
d4b4084a | 2609 | bool can_split_folio(struct folio *folio, int *pextra_pins) |
b8f593cd HY |
2610 | { |
2611 | int extra_pins; | |
2612 | ||
aa5dc07f | 2613 | /* Additional pins from page cache */ |
d4b4084a MWO |
2614 | if (folio_test_anon(folio)) |
2615 | extra_pins = folio_test_swapcache(folio) ? | |
2616 | folio_nr_pages(folio) : 0; | |
b8f593cd | 2617 | else |
d4b4084a | 2618 | extra_pins = folio_nr_pages(folio); |
b8f593cd HY |
2619 | if (pextra_pins) |
2620 | *pextra_pins = extra_pins; | |
d4b4084a | 2621 | return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; |
b8f593cd HY |
2622 | } |
2623 | ||
e9b61f19 KS |
2624 | /* |
2625 | * This function splits huge page into normal pages. @page can point to any | |
2626 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2627 | * | |
2628 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2629 | * The huge page must be locked. | |
2630 | * | |
2631 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2632 | * | |
2633 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2634 | * the hugepage. | |
2635 | * | |
2636 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2637 | * they are not mapped. | |
2638 | * | |
2639 | * Returns 0 if the hugepage is split successfully. | |
2640 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2641 | * us. | |
2642 | */ | |
2643 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2644 | { | |
4eecb8b9 | 2645 | struct folio *folio = page_folio(page); |
f8baa6be | 2646 | struct deferred_split *ds_queue = get_deferred_split_queue(folio); |
3e9a13da | 2647 | XA_STATE(xas, &folio->mapping->i_pages, folio->index); |
baa355fd KS |
2648 | struct anon_vma *anon_vma = NULL; |
2649 | struct address_space *mapping = NULL; | |
504e070d | 2650 | int extra_pins, ret; |
006d3ff2 | 2651 | pgoff_t end; |
478d134e | 2652 | bool is_hzp; |
e9b61f19 | 2653 | |
3e9a13da MWO |
2654 | VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); |
2655 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); | |
e9b61f19 | 2656 | |
3e9a13da MWO |
2657 | is_hzp = is_huge_zero_page(&folio->page); |
2658 | VM_WARN_ON_ONCE_FOLIO(is_hzp, folio); | |
478d134e XY |
2659 | if (is_hzp) |
2660 | return -EBUSY; | |
2661 | ||
3e9a13da | 2662 | if (folio_test_writeback(folio)) |
59807685 HY |
2663 | return -EBUSY; |
2664 | ||
3e9a13da | 2665 | if (folio_test_anon(folio)) { |
baa355fd | 2666 | /* |
c1e8d7c6 | 2667 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2668 | * prevent the anon_vma disappearing so we first we take a |
2669 | * reference to it and then lock the anon_vma for write. This | |
2f031c6f | 2670 | * is similar to folio_lock_anon_vma_read except the write lock |
baa355fd KS |
2671 | * is taken to serialise against parallel split or collapse |
2672 | * operations. | |
2673 | */ | |
29eea9b5 | 2674 | anon_vma = folio_get_anon_vma(folio); |
baa355fd KS |
2675 | if (!anon_vma) { |
2676 | ret = -EBUSY; | |
2677 | goto out; | |
2678 | } | |
006d3ff2 | 2679 | end = -1; |
baa355fd KS |
2680 | mapping = NULL; |
2681 | anon_vma_lock_write(anon_vma); | |
2682 | } else { | |
6a3edd29 YF |
2683 | gfp_t gfp; |
2684 | ||
3e9a13da | 2685 | mapping = folio->mapping; |
baa355fd KS |
2686 | |
2687 | /* Truncated ? */ | |
2688 | if (!mapping) { | |
2689 | ret = -EBUSY; | |
2690 | goto out; | |
2691 | } | |
2692 | ||
6a3edd29 YF |
2693 | gfp = current_gfp_context(mapping_gfp_mask(mapping) & |
2694 | GFP_RECLAIM_MASK); | |
2695 | ||
2696 | if (folio_test_private(folio) && | |
2697 | !filemap_release_folio(folio, gfp)) { | |
2698 | ret = -EBUSY; | |
2699 | goto out; | |
2700 | } | |
2701 | ||
3e9a13da | 2702 | xas_split_alloc(&xas, folio, folio_order(folio), gfp); |
6b24ca4a MWO |
2703 | if (xas_error(&xas)) { |
2704 | ret = xas_error(&xas); | |
2705 | goto out; | |
2706 | } | |
2707 | ||
baa355fd KS |
2708 | anon_vma = NULL; |
2709 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2710 | |
2711 | /* | |
2712 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2713 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2714 | * which cannot be nested inside the page tree lock. So note | |
2715 | * end now: i_size itself may be changed at any moment, but | |
3e9a13da | 2716 | * folio lock is good enough to serialize the trimming. |
006d3ff2 HD |
2717 | */ |
2718 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
d144bf62 HD |
2719 | if (shmem_mapping(mapping)) |
2720 | end = shmem_fallocend(mapping->host, end); | |
e9b61f19 | 2721 | } |
e9b61f19 KS |
2722 | |
2723 | /* | |
684555aa | 2724 | * Racy check if we can split the page, before unmap_folio() will |
e9b61f19 KS |
2725 | * split PMDs |
2726 | */ | |
d4b4084a | 2727 | if (!can_split_folio(folio, &extra_pins)) { |
fd4a7ac3 | 2728 | ret = -EAGAIN; |
e9b61f19 KS |
2729 | goto out_unlock; |
2730 | } | |
2731 | ||
684555aa | 2732 | unmap_folio(folio); |
e9b61f19 | 2733 | |
b6769834 AS |
2734 | /* block interrupt reentry in xa_lock and spinlock */ |
2735 | local_irq_disable(); | |
baa355fd | 2736 | if (mapping) { |
baa355fd | 2737 | /* |
3e9a13da MWO |
2738 | * Check if the folio is present in page cache. |
2739 | * We assume all tail are present too, if folio is there. | |
baa355fd | 2740 | */ |
6b24ca4a MWO |
2741 | xas_lock(&xas); |
2742 | xas_reset(&xas); | |
3e9a13da | 2743 | if (xas_load(&xas) != folio) |
baa355fd KS |
2744 | goto fail; |
2745 | } | |
2746 | ||
0139aa7b | 2747 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2748 | spin_lock(&ds_queue->split_queue_lock); |
3e9a13da | 2749 | if (folio_ref_freeze(folio, 1 + extra_pins)) { |
4375a553 | 2750 | if (!list_empty(&folio->_deferred_list)) { |
364c1eeb | 2751 | ds_queue->split_queue_len--; |
4375a553 | 2752 | list_del(&folio->_deferred_list); |
9a982250 | 2753 | } |
afb97172 | 2754 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2755 | if (mapping) { |
3e9a13da | 2756 | int nr = folio_nr_pages(folio); |
bf9ecead | 2757 | |
3e9a13da MWO |
2758 | xas_split(&xas, folio, folio_order(folio)); |
2759 | if (folio_test_swapbacked(folio)) { | |
2760 | __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, | |
57b2847d | 2761 | -nr); |
1ca7554d | 2762 | } else { |
3e9a13da | 2763 | __lruvec_stat_mod_folio(folio, NR_FILE_THPS, |
bf9ecead | 2764 | -nr); |
1ca7554d MS |
2765 | filemap_nr_thps_dec(mapping); |
2766 | } | |
06d3eff6 KS |
2767 | } |
2768 | ||
b6769834 | 2769 | __split_huge_page(page, list, end); |
c4f9c701 | 2770 | ret = 0; |
e9b61f19 | 2771 | } else { |
364c1eeb | 2772 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2773 | fail: |
2774 | if (mapping) | |
6b24ca4a | 2775 | xas_unlock(&xas); |
b6769834 | 2776 | local_irq_enable(); |
4eecb8b9 | 2777 | remap_page(folio, folio_nr_pages(folio)); |
fd4a7ac3 | 2778 | ret = -EAGAIN; |
e9b61f19 KS |
2779 | } |
2780 | ||
2781 | out_unlock: | |
baa355fd KS |
2782 | if (anon_vma) { |
2783 | anon_vma_unlock_write(anon_vma); | |
2784 | put_anon_vma(anon_vma); | |
2785 | } | |
2786 | if (mapping) | |
2787 | i_mmap_unlock_read(mapping); | |
e9b61f19 | 2788 | out: |
69a37a8b | 2789 | xas_destroy(&xas); |
e9b61f19 KS |
2790 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); |
2791 | return ret; | |
2792 | } | |
9a982250 KS |
2793 | |
2794 | void free_transhuge_page(struct page *page) | |
2795 | { | |
8991de90 | 2796 | struct folio *folio = (struct folio *)page; |
f8baa6be | 2797 | struct deferred_split *ds_queue = get_deferred_split_queue(folio); |
9a982250 KS |
2798 | unsigned long flags; |
2799 | ||
364c1eeb | 2800 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
8991de90 | 2801 | if (!list_empty(&folio->_deferred_list)) { |
364c1eeb | 2802 | ds_queue->split_queue_len--; |
8991de90 | 2803 | list_del(&folio->_deferred_list); |
9a982250 | 2804 | } |
364c1eeb | 2805 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2806 | free_compound_page(page); |
2807 | } | |
2808 | ||
f158ed61 | 2809 | void deferred_split_folio(struct folio *folio) |
9a982250 | 2810 | { |
f8baa6be | 2811 | struct deferred_split *ds_queue = get_deferred_split_queue(folio); |
87eaceb3 | 2812 | #ifdef CONFIG_MEMCG |
8991de90 | 2813 | struct mem_cgroup *memcg = folio_memcg(folio); |
87eaceb3 | 2814 | #endif |
9a982250 KS |
2815 | unsigned long flags; |
2816 | ||
8991de90 | 2817 | VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); |
9a982250 | 2818 | |
87eaceb3 YS |
2819 | /* |
2820 | * The try_to_unmap() in page reclaim path might reach here too, | |
2821 | * this may cause a race condition to corrupt deferred split queue. | |
8991de90 | 2822 | * And, if page reclaim is already handling the same folio, it is |
87eaceb3 YS |
2823 | * unnecessary to handle it again in shrinker. |
2824 | * | |
8991de90 MWO |
2825 | * Check the swapcache flag to determine if the folio is being |
2826 | * handled by page reclaim since THP swap would add the folio into | |
87eaceb3 YS |
2827 | * swap cache before calling try_to_unmap(). |
2828 | */ | |
8991de90 | 2829 | if (folio_test_swapcache(folio)) |
87eaceb3 YS |
2830 | return; |
2831 | ||
8991de90 | 2832 | if (!list_empty(&folio->_deferred_list)) |
87eaceb3 YS |
2833 | return; |
2834 | ||
364c1eeb | 2835 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
8991de90 | 2836 | if (list_empty(&folio->_deferred_list)) { |
f9719a03 | 2837 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
8991de90 | 2838 | list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); |
364c1eeb | 2839 | ds_queue->split_queue_len++; |
87eaceb3 YS |
2840 | #ifdef CONFIG_MEMCG |
2841 | if (memcg) | |
8991de90 | 2842 | set_shrinker_bit(memcg, folio_nid(folio), |
2bfd3637 | 2843 | deferred_split_shrinker.id); |
87eaceb3 | 2844 | #endif |
9a982250 | 2845 | } |
364c1eeb | 2846 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2847 | } |
2848 | ||
2849 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2850 | struct shrink_control *sc) | |
2851 | { | |
a3d0a918 | 2852 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2853 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2854 | |
2855 | #ifdef CONFIG_MEMCG | |
2856 | if (sc->memcg) | |
2857 | ds_queue = &sc->memcg->deferred_split_queue; | |
2858 | #endif | |
364c1eeb | 2859 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2860 | } |
2861 | ||
2862 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2863 | struct shrink_control *sc) | |
2864 | { | |
a3d0a918 | 2865 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2866 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 | 2867 | unsigned long flags; |
4375a553 MWO |
2868 | LIST_HEAD(list); |
2869 | struct folio *folio, *next; | |
9a982250 KS |
2870 | int split = 0; |
2871 | ||
87eaceb3 YS |
2872 | #ifdef CONFIG_MEMCG |
2873 | if (sc->memcg) | |
2874 | ds_queue = &sc->memcg->deferred_split_queue; | |
2875 | #endif | |
2876 | ||
364c1eeb | 2877 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2878 | /* Take pin on all head pages to avoid freeing them under us */ |
4375a553 MWO |
2879 | list_for_each_entry_safe(folio, next, &ds_queue->split_queue, |
2880 | _deferred_list) { | |
2881 | if (folio_try_get(folio)) { | |
2882 | list_move(&folio->_deferred_list, &list); | |
e3ae1953 | 2883 | } else { |
4375a553 MWO |
2884 | /* We lost race with folio_put() */ |
2885 | list_del_init(&folio->_deferred_list); | |
364c1eeb | 2886 | ds_queue->split_queue_len--; |
9a982250 | 2887 | } |
e3ae1953 KS |
2888 | if (!--sc->nr_to_scan) |
2889 | break; | |
9a982250 | 2890 | } |
364c1eeb | 2891 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 | 2892 | |
4375a553 MWO |
2893 | list_for_each_entry_safe(folio, next, &list, _deferred_list) { |
2894 | if (!folio_trylock(folio)) | |
fa41b900 | 2895 | goto next; |
9a982250 | 2896 | /* split_huge_page() removes page from list on success */ |
4375a553 | 2897 | if (!split_folio(folio)) |
9a982250 | 2898 | split++; |
4375a553 | 2899 | folio_unlock(folio); |
fa41b900 | 2900 | next: |
4375a553 | 2901 | folio_put(folio); |
9a982250 KS |
2902 | } |
2903 | ||
364c1eeb YS |
2904 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2905 | list_splice_tail(&list, &ds_queue->split_queue); | |
2906 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2907 | |
cb8d68ec KS |
2908 | /* |
2909 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2910 | * This can happen if pages were freed under us. | |
2911 | */ | |
364c1eeb | 2912 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2913 | return SHRINK_STOP; |
2914 | return split; | |
9a982250 KS |
2915 | } |
2916 | ||
2917 | static struct shrinker deferred_split_shrinker = { | |
2918 | .count_objects = deferred_split_count, | |
2919 | .scan_objects = deferred_split_scan, | |
2920 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2921 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2922 | SHRINKER_NONSLAB, | |
9a982250 | 2923 | }; |
49071d43 KS |
2924 | |
2925 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2926 | static void split_huge_pages_all(void) |
49071d43 KS |
2927 | { |
2928 | struct zone *zone; | |
2929 | struct page *page; | |
630e7c5e | 2930 | struct folio *folio; |
49071d43 KS |
2931 | unsigned long pfn, max_zone_pfn; |
2932 | unsigned long total = 0, split = 0; | |
2933 | ||
fa6c0231 | 2934 | pr_debug("Split all THPs\n"); |
a17206da ML |
2935 | for_each_zone(zone) { |
2936 | if (!managed_zone(zone)) | |
2937 | continue; | |
49071d43 KS |
2938 | max_zone_pfn = zone_end_pfn(zone); |
2939 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
a17206da | 2940 | int nr_pages; |
49071d43 | 2941 | |
2b7aa91b | 2942 | page = pfn_to_online_page(pfn); |
630e7c5e KW |
2943 | if (!page || PageTail(page)) |
2944 | continue; | |
2945 | folio = page_folio(page); | |
2946 | if (!folio_try_get(folio)) | |
49071d43 KS |
2947 | continue; |
2948 | ||
630e7c5e | 2949 | if (unlikely(page_folio(page) != folio)) |
49071d43 KS |
2950 | goto next; |
2951 | ||
630e7c5e | 2952 | if (zone != folio_zone(folio)) |
49071d43 KS |
2953 | goto next; |
2954 | ||
630e7c5e KW |
2955 | if (!folio_test_large(folio) |
2956 | || folio_test_hugetlb(folio) | |
2957 | || !folio_test_lru(folio)) | |
49071d43 KS |
2958 | goto next; |
2959 | ||
2960 | total++; | |
630e7c5e KW |
2961 | folio_lock(folio); |
2962 | nr_pages = folio_nr_pages(folio); | |
2963 | if (!split_folio(folio)) | |
49071d43 | 2964 | split++; |
a17206da | 2965 | pfn += nr_pages - 1; |
630e7c5e | 2966 | folio_unlock(folio); |
49071d43 | 2967 | next: |
630e7c5e | 2968 | folio_put(folio); |
fa6c0231 | 2969 | cond_resched(); |
49071d43 KS |
2970 | } |
2971 | } | |
2972 | ||
fa6c0231 ZY |
2973 | pr_debug("%lu of %lu THP split\n", split, total); |
2974 | } | |
49071d43 | 2975 | |
fa6c0231 ZY |
2976 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2977 | { | |
2978 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2979 | is_vm_hugetlb_page(vma); | |
2980 | } | |
2981 | ||
2982 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2983 | unsigned long vaddr_end) | |
2984 | { | |
2985 | int ret = 0; | |
2986 | struct task_struct *task; | |
2987 | struct mm_struct *mm; | |
2988 | unsigned long total = 0, split = 0; | |
2989 | unsigned long addr; | |
2990 | ||
2991 | vaddr_start &= PAGE_MASK; | |
2992 | vaddr_end &= PAGE_MASK; | |
2993 | ||
2994 | /* Find the task_struct from pid */ | |
2995 | rcu_read_lock(); | |
2996 | task = find_task_by_vpid(pid); | |
2997 | if (!task) { | |
2998 | rcu_read_unlock(); | |
2999 | ret = -ESRCH; | |
3000 | goto out; | |
3001 | } | |
3002 | get_task_struct(task); | |
3003 | rcu_read_unlock(); | |
3004 | ||
3005 | /* Find the mm_struct */ | |
3006 | mm = get_task_mm(task); | |
3007 | put_task_struct(task); | |
3008 | ||
3009 | if (!mm) { | |
3010 | ret = -EINVAL; | |
3011 | goto out; | |
3012 | } | |
3013 | ||
3014 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
3015 | pid, vaddr_start, vaddr_end); | |
3016 | ||
3017 | mmap_read_lock(mm); | |
3018 | /* | |
3019 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
3020 | * table filled with PTE-mapped THPs, each of which is distinct. | |
3021 | */ | |
3022 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
74ba2b38 | 3023 | struct vm_area_struct *vma = vma_lookup(mm, addr); |
fa6c0231 ZY |
3024 | struct page *page; |
3025 | ||
74ba2b38 | 3026 | if (!vma) |
fa6c0231 ZY |
3027 | break; |
3028 | ||
3029 | /* skip special VMA and hugetlb VMA */ | |
3030 | if (vma_not_suitable_for_thp_split(vma)) { | |
3031 | addr = vma->vm_end; | |
3032 | continue; | |
3033 | } | |
3034 | ||
3035 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
87d2762e | 3036 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
fa6c0231 | 3037 | |
f7091ed6 | 3038 | if (IS_ERR_OR_NULL(page)) |
fa6c0231 ZY |
3039 | continue; |
3040 | ||
3041 | if (!is_transparent_hugepage(page)) | |
3042 | goto next; | |
3043 | ||
3044 | total++; | |
d4b4084a | 3045 | if (!can_split_folio(page_folio(page), NULL)) |
fa6c0231 ZY |
3046 | goto next; |
3047 | ||
3048 | if (!trylock_page(page)) | |
3049 | goto next; | |
3050 | ||
3051 | if (!split_huge_page(page)) | |
3052 | split++; | |
3053 | ||
3054 | unlock_page(page); | |
3055 | next: | |
3056 | put_page(page); | |
3057 | cond_resched(); | |
3058 | } | |
3059 | mmap_read_unlock(mm); | |
3060 | mmput(mm); | |
3061 | ||
3062 | pr_debug("%lu of %lu THP split\n", split, total); | |
3063 | ||
3064 | out: | |
3065 | return ret; | |
49071d43 | 3066 | } |
fa6c0231 | 3067 | |
fbe37501 ZY |
3068 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
3069 | pgoff_t off_end) | |
3070 | { | |
3071 | struct filename *file; | |
3072 | struct file *candidate; | |
3073 | struct address_space *mapping; | |
3074 | int ret = -EINVAL; | |
3075 | pgoff_t index; | |
3076 | int nr_pages = 1; | |
3077 | unsigned long total = 0, split = 0; | |
3078 | ||
3079 | file = getname_kernel(file_path); | |
3080 | if (IS_ERR(file)) | |
3081 | return ret; | |
3082 | ||
3083 | candidate = file_open_name(file, O_RDONLY, 0); | |
3084 | if (IS_ERR(candidate)) | |
3085 | goto out; | |
3086 | ||
3087 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
3088 | file_path, off_start, off_end); | |
3089 | ||
3090 | mapping = candidate->f_mapping; | |
3091 | ||
3092 | for (index = off_start; index < off_end; index += nr_pages) { | |
9ee2c086 MWO |
3093 | struct folio *folio = __filemap_get_folio(mapping, index, |
3094 | FGP_ENTRY, 0); | |
fbe37501 ZY |
3095 | |
3096 | nr_pages = 1; | |
9ee2c086 | 3097 | if (xa_is_value(folio) || !folio) |
fbe37501 ZY |
3098 | continue; |
3099 | ||
9ee2c086 | 3100 | if (!folio_test_large(folio)) |
fbe37501 ZY |
3101 | goto next; |
3102 | ||
3103 | total++; | |
9ee2c086 | 3104 | nr_pages = folio_nr_pages(folio); |
fbe37501 | 3105 | |
9ee2c086 | 3106 | if (!folio_trylock(folio)) |
fbe37501 ZY |
3107 | goto next; |
3108 | ||
9ee2c086 | 3109 | if (!split_folio(folio)) |
fbe37501 ZY |
3110 | split++; |
3111 | ||
9ee2c086 | 3112 | folio_unlock(folio); |
fbe37501 | 3113 | next: |
9ee2c086 | 3114 | folio_put(folio); |
fbe37501 ZY |
3115 | cond_resched(); |
3116 | } | |
3117 | ||
3118 | filp_close(candidate, NULL); | |
3119 | ret = 0; | |
3120 | ||
3121 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3122 | out: | |
3123 | putname(file); | |
3124 | return ret; | |
3125 | } | |
3126 | ||
fa6c0231 ZY |
3127 | #define MAX_INPUT_BUF_SZ 255 |
3128 | ||
3129 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3130 | size_t count, loff_t *ppops) | |
3131 | { | |
3132 | static DEFINE_MUTEX(split_debug_mutex); | |
3133 | ssize_t ret; | |
fbe37501 ZY |
3134 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3135 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3136 | int pid; |
3137 | unsigned long vaddr_start, vaddr_end; | |
3138 | ||
3139 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3140 | if (ret) | |
3141 | return ret; | |
3142 | ||
3143 | ret = -EFAULT; | |
3144 | ||
3145 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3146 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3147 | goto out; | |
3148 | ||
3149 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3150 | |
3151 | if (input_buf[0] == '/') { | |
3152 | char *tok; | |
3153 | char *buf = input_buf; | |
3154 | char file_path[MAX_INPUT_BUF_SZ]; | |
3155 | pgoff_t off_start = 0, off_end = 0; | |
3156 | size_t input_len = strlen(input_buf); | |
3157 | ||
3158 | tok = strsep(&buf, ","); | |
3159 | if (tok) { | |
1212e00c | 3160 | strcpy(file_path, tok); |
fbe37501 ZY |
3161 | } else { |
3162 | ret = -EINVAL; | |
3163 | goto out; | |
3164 | } | |
3165 | ||
3166 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3167 | if (ret != 2) { | |
3168 | ret = -EINVAL; | |
3169 | goto out; | |
3170 | } | |
3171 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3172 | if (!ret) | |
3173 | ret = input_len; | |
3174 | ||
3175 | goto out; | |
3176 | } | |
3177 | ||
fa6c0231 ZY |
3178 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3179 | if (ret == 1 && pid == 1) { | |
3180 | split_huge_pages_all(); | |
3181 | ret = strlen(input_buf); | |
3182 | goto out; | |
3183 | } else if (ret != 3) { | |
3184 | ret = -EINVAL; | |
3185 | goto out; | |
3186 | } | |
3187 | ||
3188 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3189 | if (!ret) | |
3190 | ret = strlen(input_buf); | |
3191 | out: | |
3192 | mutex_unlock(&split_debug_mutex); | |
3193 | return ret; | |
3194 | ||
3195 | } | |
3196 | ||
3197 | static const struct file_operations split_huge_pages_fops = { | |
3198 | .owner = THIS_MODULE, | |
3199 | .write = split_huge_pages_write, | |
3200 | .llseek = no_llseek, | |
3201 | }; | |
49071d43 KS |
3202 | |
3203 | static int __init split_huge_pages_debugfs(void) | |
3204 | { | |
d9f7979c GKH |
3205 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3206 | &split_huge_pages_fops); | |
49071d43 KS |
3207 | return 0; |
3208 | } | |
3209 | late_initcall(split_huge_pages_debugfs); | |
3210 | #endif | |
616b8371 ZY |
3211 | |
3212 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
7f5abe60 | 3213 | int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, |
616b8371 ZY |
3214 | struct page *page) |
3215 | { | |
3216 | struct vm_area_struct *vma = pvmw->vma; | |
3217 | struct mm_struct *mm = vma->vm_mm; | |
3218 | unsigned long address = pvmw->address; | |
6c287605 | 3219 | bool anon_exclusive; |
616b8371 ZY |
3220 | pmd_t pmdval; |
3221 | swp_entry_t entry; | |
ab6e3d09 | 3222 | pmd_t pmdswp; |
616b8371 ZY |
3223 | |
3224 | if (!(pvmw->pmd && !pvmw->pte)) | |
7f5abe60 | 3225 | return 0; |
616b8371 | 3226 | |
616b8371 | 3227 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3228 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
6c287605 | 3229 | |
088b8aa5 | 3230 | /* See page_try_share_anon_rmap(): invalidate PMD first. */ |
6c287605 DH |
3231 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); |
3232 | if (anon_exclusive && page_try_share_anon_rmap(page)) { | |
3233 | set_pmd_at(mm, address, pvmw->pmd, pmdval); | |
7f5abe60 | 3234 | return -EBUSY; |
6c287605 DH |
3235 | } |
3236 | ||
616b8371 ZY |
3237 | if (pmd_dirty(pmdval)) |
3238 | set_page_dirty(page); | |
4dd845b5 AP |
3239 | if (pmd_write(pmdval)) |
3240 | entry = make_writable_migration_entry(page_to_pfn(page)); | |
6c287605 DH |
3241 | else if (anon_exclusive) |
3242 | entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); | |
4dd845b5 AP |
3243 | else |
3244 | entry = make_readable_migration_entry(page_to_pfn(page)); | |
2e346877 PX |
3245 | if (pmd_young(pmdval)) |
3246 | entry = make_migration_entry_young(entry); | |
3247 | if (pmd_dirty(pmdval)) | |
3248 | entry = make_migration_entry_dirty(entry); | |
ab6e3d09 NH |
3249 | pmdswp = swp_entry_to_pmd(entry); |
3250 | if (pmd_soft_dirty(pmdval)) | |
3251 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3252 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
cea86fe2 | 3253 | page_remove_rmap(page, vma, true); |
616b8371 | 3254 | put_page(page); |
283fd6fe | 3255 | trace_set_migration_pmd(address, pmd_val(pmdswp)); |
7f5abe60 DH |
3256 | |
3257 | return 0; | |
616b8371 ZY |
3258 | } |
3259 | ||
3260 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3261 | { | |
3262 | struct vm_area_struct *vma = pvmw->vma; | |
3263 | struct mm_struct *mm = vma->vm_mm; | |
3264 | unsigned long address = pvmw->address; | |
4fba8f2a | 3265 | unsigned long haddr = address & HPAGE_PMD_MASK; |
616b8371 ZY |
3266 | pmd_t pmde; |
3267 | swp_entry_t entry; | |
3268 | ||
3269 | if (!(pvmw->pmd && !pvmw->pte)) | |
3270 | return; | |
3271 | ||
3272 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3273 | get_page(new); | |
2e346877 | 3274 | pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); |
ab6e3d09 NH |
3275 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3276 | pmde = pmd_mksoft_dirty(pmde); | |
8f34f1ea | 3277 | if (pmd_swp_uffd_wp(*pvmw->pmd)) |
f1eb1bac | 3278 | pmde = pmd_mkuffd_wp(pmde); |
2e346877 PX |
3279 | if (!is_migration_entry_young(entry)) |
3280 | pmde = pmd_mkold(pmde); | |
3281 | /* NOTE: this may contain setting soft-dirty on some archs */ | |
3282 | if (PageDirty(new) && is_migration_entry_dirty(entry)) | |
3283 | pmde = pmd_mkdirty(pmde); | |
96a9c287 PX |
3284 | if (is_writable_migration_entry(entry)) |
3285 | pmde = maybe_pmd_mkwrite(pmde, vma); | |
3286 | else | |
3287 | pmde = pmd_wrprotect(pmde); | |
616b8371 | 3288 | |
6c287605 DH |
3289 | if (PageAnon(new)) { |
3290 | rmap_t rmap_flags = RMAP_COMPOUND; | |
3291 | ||
3292 | if (!is_readable_migration_entry(entry)) | |
3293 | rmap_flags |= RMAP_EXCLUSIVE; | |
3294 | ||
4fba8f2a | 3295 | page_add_anon_rmap(new, vma, haddr, rmap_flags); |
6c287605 | 3296 | } else { |
cea86fe2 | 3297 | page_add_file_rmap(new, vma, true); |
6c287605 DH |
3298 | } |
3299 | VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); | |
4fba8f2a | 3300 | set_pmd_at(mm, haddr, pvmw->pmd, pmde); |
5cbcf225 MS |
3301 | |
3302 | /* No need to invalidate - it was non-present before */ | |
616b8371 | 3303 | update_mmu_cache_pmd(vma, address, pvmw->pmd); |
283fd6fe | 3304 | trace_remove_migration_pmd(address, pmd_val(pmde)); |
616b8371 ZY |
3305 | } |
3306 | #endif |