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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)) | |
7c6c6cc4 | 122 | return shmem_huge_enabled(vma, !enforce_sysfs); |
9fec5168 | 123 | |
a7f4e6e4 ZK |
124 | /* Enforce sysfs THP requirements as necessary */ |
125 | if (enforce_sysfs && | |
126 | (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && | |
127 | !hugepage_flags_always()))) | |
9fec5168 YS |
128 | return false; |
129 | ||
130 | /* Only regular file is valid */ | |
7da4e2cb | 131 | if (!in_pf && file_thp_enabled(vma)) |
78d12c19 | 132 | return true; |
7635d9cb | 133 | |
9fec5168 YS |
134 | if (!vma_is_anonymous(vma)) |
135 | return false; | |
136 | ||
137 | if (vma_is_temporary_stack(vma)) | |
138 | return false; | |
139 | ||
140 | /* | |
141 | * THPeligible bit of smaps should show 1 for proper VMAs even | |
142 | * though anon_vma is not initialized yet. | |
7da4e2cb YS |
143 | * |
144 | * Allow page fault since anon_vma may be not initialized until | |
145 | * the first page fault. | |
9fec5168 YS |
146 | */ |
147 | if (!vma->anon_vma) | |
7da4e2cb | 148 | return (smaps || in_pf); |
9fec5168 YS |
149 | |
150 | return true; | |
7635d9cb MH |
151 | } |
152 | ||
aaa9705b | 153 | static bool get_huge_zero_page(void) |
97ae1749 KS |
154 | { |
155 | struct page *zero_page; | |
156 | retry: | |
157 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
aaa9705b | 158 | return true; |
97ae1749 KS |
159 | |
160 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 161 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
162 | if (!zero_page) { |
163 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
aaa9705b | 164 | return false; |
d8a8e1f0 | 165 | } |
97ae1749 | 166 | preempt_disable(); |
5918d10a | 167 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 | 168 | preempt_enable(); |
5ddacbe9 | 169 | __free_pages(zero_page, compound_order(zero_page)); |
97ae1749 KS |
170 | goto retry; |
171 | } | |
3b77e8c8 | 172 | WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); |
97ae1749 KS |
173 | |
174 | /* We take additional reference here. It will be put back by shrinker */ | |
175 | atomic_set(&huge_zero_refcount, 2); | |
176 | preempt_enable(); | |
f4981502 | 177 | count_vm_event(THP_ZERO_PAGE_ALLOC); |
aaa9705b | 178 | return true; |
4a6c1297 KS |
179 | } |
180 | ||
6fcb52a5 | 181 | static void put_huge_zero_page(void) |
4a6c1297 | 182 | { |
97ae1749 KS |
183 | /* |
184 | * Counter should never go to zero here. Only shrinker can put | |
185 | * last reference. | |
186 | */ | |
187 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
188 | } |
189 | ||
6fcb52a5 AL |
190 | struct page *mm_get_huge_zero_page(struct mm_struct *mm) |
191 | { | |
192 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
193 | return READ_ONCE(huge_zero_page); | |
194 | ||
195 | if (!get_huge_zero_page()) | |
196 | return NULL; | |
197 | ||
198 | if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
199 | put_huge_zero_page(); | |
200 | ||
201 | return READ_ONCE(huge_zero_page); | |
202 | } | |
203 | ||
204 | void mm_put_huge_zero_page(struct mm_struct *mm) | |
205 | { | |
206 | if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags)) | |
207 | put_huge_zero_page(); | |
208 | } | |
209 | ||
48896466 GC |
210 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
211 | struct shrink_control *sc) | |
4a6c1297 | 212 | { |
48896466 GC |
213 | /* we can free zero page only if last reference remains */ |
214 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
215 | } | |
97ae1749 | 216 | |
48896466 GC |
217 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
218 | struct shrink_control *sc) | |
219 | { | |
97ae1749 | 220 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
221 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
222 | BUG_ON(zero_page == NULL); | |
3b77e8c8 | 223 | WRITE_ONCE(huge_zero_pfn, ~0UL); |
5ddacbe9 | 224 | __free_pages(zero_page, compound_order(zero_page)); |
48896466 | 225 | return HPAGE_PMD_NR; |
97ae1749 KS |
226 | } |
227 | ||
228 | return 0; | |
4a6c1297 KS |
229 | } |
230 | ||
97ae1749 | 231 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
232 | .count_objects = shrink_huge_zero_page_count, |
233 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
234 | .seeks = DEFAULT_SEEKS, |
235 | }; | |
236 | ||
71e3aac0 | 237 | #ifdef CONFIG_SYSFS |
71e3aac0 AA |
238 | static ssize_t enabled_show(struct kobject *kobj, |
239 | struct kobj_attribute *attr, char *buf) | |
240 | { | |
bfb0ffeb JP |
241 | const char *output; |
242 | ||
444eb2a4 | 243 | if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags)) |
bfb0ffeb JP |
244 | output = "[always] madvise never"; |
245 | else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
246 | &transparent_hugepage_flags)) | |
247 | output = "always [madvise] never"; | |
444eb2a4 | 248 | else |
bfb0ffeb JP |
249 | output = "always madvise [never]"; |
250 | ||
251 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 252 | } |
444eb2a4 | 253 | |
71e3aac0 AA |
254 | static ssize_t enabled_store(struct kobject *kobj, |
255 | struct kobj_attribute *attr, | |
256 | const char *buf, size_t count) | |
257 | { | |
21440d7e | 258 | ssize_t ret = count; |
ba76149f | 259 | |
f42f2552 | 260 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
261 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); |
262 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 263 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
264 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
265 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 266 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
267 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags); |
268 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
269 | } else | |
270 | ret = -EINVAL; | |
ba76149f AA |
271 | |
272 | if (ret > 0) { | |
b46e756f | 273 | int err = start_stop_khugepaged(); |
ba76149f AA |
274 | if (err) |
275 | ret = err; | |
276 | } | |
ba76149f | 277 | return ret; |
71e3aac0 | 278 | } |
37139bb0 ML |
279 | |
280 | static struct kobj_attribute enabled_attr = __ATTR_RW(enabled); | |
71e3aac0 | 281 | |
b46e756f | 282 | ssize_t single_hugepage_flag_show(struct kobject *kobj, |
bfb0ffeb JP |
283 | struct kobj_attribute *attr, char *buf, |
284 | enum transparent_hugepage_flag flag) | |
71e3aac0 | 285 | { |
bfb0ffeb JP |
286 | return sysfs_emit(buf, "%d\n", |
287 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 288 | } |
e27e6151 | 289 | |
b46e756f | 290 | ssize_t single_hugepage_flag_store(struct kobject *kobj, |
71e3aac0 AA |
291 | struct kobj_attribute *attr, |
292 | const char *buf, size_t count, | |
293 | enum transparent_hugepage_flag flag) | |
294 | { | |
e27e6151 BH |
295 | unsigned long value; |
296 | int ret; | |
297 | ||
298 | ret = kstrtoul(buf, 10, &value); | |
299 | if (ret < 0) | |
300 | return ret; | |
301 | if (value > 1) | |
302 | return -EINVAL; | |
303 | ||
304 | if (value) | |
71e3aac0 | 305 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 306 | else |
71e3aac0 | 307 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
308 | |
309 | return count; | |
310 | } | |
311 | ||
71e3aac0 AA |
312 | static ssize_t defrag_show(struct kobject *kobj, |
313 | struct kobj_attribute *attr, char *buf) | |
314 | { | |
bfb0ffeb JP |
315 | const char *output; |
316 | ||
317 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, | |
318 | &transparent_hugepage_flags)) | |
319 | output = "[always] defer defer+madvise madvise never"; | |
320 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, | |
321 | &transparent_hugepage_flags)) | |
322 | output = "always [defer] defer+madvise madvise never"; | |
323 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, | |
324 | &transparent_hugepage_flags)) | |
325 | output = "always defer [defer+madvise] madvise never"; | |
326 | else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, | |
327 | &transparent_hugepage_flags)) | |
328 | output = "always defer defer+madvise [madvise] never"; | |
329 | else | |
330 | output = "always defer defer+madvise madvise [never]"; | |
331 | ||
332 | return sysfs_emit(buf, "%s\n", output); | |
71e3aac0 | 333 | } |
21440d7e | 334 | |
71e3aac0 AA |
335 | static ssize_t defrag_store(struct kobject *kobj, |
336 | struct kobj_attribute *attr, | |
337 | const char *buf, size_t count) | |
338 | { | |
f42f2552 | 339 | if (sysfs_streq(buf, "always")) { |
21440d7e DR |
340 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); |
341 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
342 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
343 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 344 | } else if (sysfs_streq(buf, "defer+madvise")) { |
21440d7e DR |
345 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
346 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
347 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
348 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 349 | } else if (sysfs_streq(buf, "defer")) { |
4fad7fb6 DR |
350 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
351 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
352 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
353 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 354 | } else if (sysfs_streq(buf, "madvise")) { |
21440d7e DR |
355 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
356 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
357 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
358 | set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
f42f2552 | 359 | } else if (sysfs_streq(buf, "never")) { |
21440d7e DR |
360 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); |
361 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); | |
362 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); | |
363 | clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); | |
364 | } else | |
365 | return -EINVAL; | |
366 | ||
367 | return count; | |
71e3aac0 | 368 | } |
37139bb0 | 369 | static struct kobj_attribute defrag_attr = __ATTR_RW(defrag); |
71e3aac0 | 370 | |
79da5407 | 371 | static ssize_t use_zero_page_show(struct kobject *kobj, |
ae7a927d | 372 | struct kobj_attribute *attr, char *buf) |
79da5407 | 373 | { |
b46e756f | 374 | return single_hugepage_flag_show(kobj, attr, buf, |
ae7a927d | 375 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
79da5407 KS |
376 | } |
377 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
378 | struct kobj_attribute *attr, const char *buf, size_t count) | |
379 | { | |
b46e756f | 380 | return single_hugepage_flag_store(kobj, attr, buf, count, |
79da5407 KS |
381 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); |
382 | } | |
37139bb0 | 383 | static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page); |
49920d28 HD |
384 | |
385 | static ssize_t hpage_pmd_size_show(struct kobject *kobj, | |
ae7a927d | 386 | struct kobj_attribute *attr, char *buf) |
49920d28 | 387 | { |
ae7a927d | 388 | return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE); |
49920d28 HD |
389 | } |
390 | static struct kobj_attribute hpage_pmd_size_attr = | |
391 | __ATTR_RO(hpage_pmd_size); | |
392 | ||
71e3aac0 AA |
393 | static struct attribute *hugepage_attr[] = { |
394 | &enabled_attr.attr, | |
395 | &defrag_attr.attr, | |
79da5407 | 396 | &use_zero_page_attr.attr, |
49920d28 | 397 | &hpage_pmd_size_attr.attr, |
396bcc52 | 398 | #ifdef CONFIG_SHMEM |
5a6e75f8 | 399 | &shmem_enabled_attr.attr, |
71e3aac0 AA |
400 | #endif |
401 | NULL, | |
402 | }; | |
403 | ||
8aa95a21 | 404 | static const struct attribute_group hugepage_attr_group = { |
71e3aac0 | 405 | .attrs = hugepage_attr, |
ba76149f AA |
406 | }; |
407 | ||
569e5590 | 408 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 409 | { |
71e3aac0 AA |
410 | int err; |
411 | ||
569e5590 SL |
412 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
413 | if (unlikely(!*hugepage_kobj)) { | |
ae3a8c1c | 414 | pr_err("failed to create transparent hugepage kobject\n"); |
569e5590 | 415 | return -ENOMEM; |
ba76149f AA |
416 | } |
417 | ||
569e5590 | 418 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 419 | if (err) { |
ae3a8c1c | 420 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 421 | goto delete_obj; |
ba76149f AA |
422 | } |
423 | ||
569e5590 | 424 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 425 | if (err) { |
ae3a8c1c | 426 | pr_err("failed to register transparent hugepage group\n"); |
569e5590 | 427 | goto remove_hp_group; |
ba76149f | 428 | } |
569e5590 SL |
429 | |
430 | return 0; | |
431 | ||
432 | remove_hp_group: | |
433 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
434 | delete_obj: | |
435 | kobject_put(*hugepage_kobj); | |
436 | return err; | |
437 | } | |
438 | ||
439 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
440 | { | |
441 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
442 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
443 | kobject_put(hugepage_kobj); | |
444 | } | |
445 | #else | |
446 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
447 | { | |
448 | return 0; | |
449 | } | |
450 | ||
451 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
452 | { | |
453 | } | |
454 | #endif /* CONFIG_SYSFS */ | |
455 | ||
456 | static int __init hugepage_init(void) | |
457 | { | |
458 | int err; | |
459 | struct kobject *hugepage_kobj; | |
460 | ||
461 | if (!has_transparent_hugepage()) { | |
bae84953 AK |
462 | /* |
463 | * Hardware doesn't support hugepages, hence disable | |
464 | * DAX PMD support. | |
465 | */ | |
466 | transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX; | |
569e5590 SL |
467 | return -EINVAL; |
468 | } | |
469 | ||
ff20c2e0 KS |
470 | /* |
471 | * hugepages can't be allocated by the buddy allocator | |
472 | */ | |
473 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER); | |
474 | /* | |
475 | * we use page->mapping and page->index in second tail page | |
476 | * as list_head: assuming THP order >= 2 | |
477 | */ | |
478 | MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); | |
479 | ||
569e5590 SL |
480 | err = hugepage_init_sysfs(&hugepage_kobj); |
481 | if (err) | |
65ebb64f | 482 | goto err_sysfs; |
ba76149f | 483 | |
b46e756f | 484 | err = khugepaged_init(); |
ba76149f | 485 | if (err) |
65ebb64f | 486 | goto err_slab; |
ba76149f | 487 | |
e33c267a | 488 | err = register_shrinker(&huge_zero_page_shrinker, "thp-zero"); |
65ebb64f KS |
489 | if (err) |
490 | goto err_hzp_shrinker; | |
e33c267a | 491 | err = register_shrinker(&deferred_split_shrinker, "thp-deferred_split"); |
9a982250 KS |
492 | if (err) |
493 | goto err_split_shrinker; | |
97ae1749 | 494 | |
97562cd2 RR |
495 | /* |
496 | * By default disable transparent hugepages on smaller systems, | |
497 | * where the extra memory used could hurt more than TLB overhead | |
498 | * is likely to save. The admin can still enable it through /sys. | |
499 | */ | |
ca79b0c2 | 500 | if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { |
97562cd2 | 501 | transparent_hugepage_flags = 0; |
79553da2 KS |
502 | return 0; |
503 | } | |
97562cd2 | 504 | |
79553da2 | 505 | err = start_stop_khugepaged(); |
65ebb64f KS |
506 | if (err) |
507 | goto err_khugepaged; | |
ba76149f | 508 | |
569e5590 | 509 | return 0; |
65ebb64f | 510 | err_khugepaged: |
9a982250 KS |
511 | unregister_shrinker(&deferred_split_shrinker); |
512 | err_split_shrinker: | |
65ebb64f KS |
513 | unregister_shrinker(&huge_zero_page_shrinker); |
514 | err_hzp_shrinker: | |
b46e756f | 515 | khugepaged_destroy(); |
65ebb64f | 516 | err_slab: |
569e5590 | 517 | hugepage_exit_sysfs(hugepage_kobj); |
65ebb64f | 518 | err_sysfs: |
ba76149f | 519 | return err; |
71e3aac0 | 520 | } |
a64fb3cd | 521 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
522 | |
523 | static int __init setup_transparent_hugepage(char *str) | |
524 | { | |
525 | int ret = 0; | |
526 | if (!str) | |
527 | goto out; | |
528 | if (!strcmp(str, "always")) { | |
529 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
530 | &transparent_hugepage_flags); | |
531 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
532 | &transparent_hugepage_flags); | |
533 | ret = 1; | |
534 | } else if (!strcmp(str, "madvise")) { | |
535 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
536 | &transparent_hugepage_flags); | |
537 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
538 | &transparent_hugepage_flags); | |
539 | ret = 1; | |
540 | } else if (!strcmp(str, "never")) { | |
541 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
542 | &transparent_hugepage_flags); | |
543 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
544 | &transparent_hugepage_flags); | |
545 | ret = 1; | |
546 | } | |
547 | out: | |
548 | if (!ret) | |
ae3a8c1c | 549 | pr_warn("transparent_hugepage= cannot parse, ignored\n"); |
71e3aac0 AA |
550 | return ret; |
551 | } | |
552 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
553 | ||
f55e1014 | 554 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 | 555 | { |
f55e1014 | 556 | if (likely(vma->vm_flags & VM_WRITE)) |
71e3aac0 AA |
557 | pmd = pmd_mkwrite(pmd); |
558 | return pmd; | |
559 | } | |
560 | ||
87eaceb3 YS |
561 | #ifdef CONFIG_MEMCG |
562 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
9a982250 | 563 | { |
bcfe06bf | 564 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 YS |
565 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); |
566 | ||
567 | if (memcg) | |
568 | return &memcg->deferred_split_queue; | |
569 | else | |
570 | return &pgdat->deferred_split_queue; | |
9a982250 | 571 | } |
87eaceb3 YS |
572 | #else |
573 | static inline struct deferred_split *get_deferred_split_queue(struct page *page) | |
574 | { | |
575 | struct pglist_data *pgdat = NODE_DATA(page_to_nid(page)); | |
576 | ||
577 | return &pgdat->deferred_split_queue; | |
578 | } | |
579 | #endif | |
9a982250 KS |
580 | |
581 | void prep_transhuge_page(struct page *page) | |
582 | { | |
583 | /* | |
d764afed | 584 | * we use page->mapping and page->index in second tail page |
9a982250 KS |
585 | * as list_head: assuming THP order >= 2 |
586 | */ | |
9a982250 KS |
587 | |
588 | INIT_LIST_HEAD(page_deferred_list(page)); | |
589 | set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); | |
590 | } | |
591 | ||
562beb72 | 592 | static inline bool is_transparent_hugepage(struct page *page) |
005ba37c SC |
593 | { |
594 | if (!PageCompound(page)) | |
fa1f68cc | 595 | return false; |
005ba37c SC |
596 | |
597 | page = compound_head(page); | |
598 | return is_huge_zero_page(page) || | |
599 | page[1].compound_dtor == TRANSHUGE_PAGE_DTOR; | |
600 | } | |
005ba37c | 601 | |
97d3d0f9 KS |
602 | static unsigned long __thp_get_unmapped_area(struct file *filp, |
603 | unsigned long addr, unsigned long len, | |
74d2fad1 TK |
604 | loff_t off, unsigned long flags, unsigned long size) |
605 | { | |
74d2fad1 TK |
606 | loff_t off_end = off + len; |
607 | loff_t off_align = round_up(off, size); | |
97d3d0f9 | 608 | unsigned long len_pad, ret; |
74d2fad1 TK |
609 | |
610 | if (off_end <= off_align || (off_end - off_align) < size) | |
611 | return 0; | |
612 | ||
613 | len_pad = len + size; | |
614 | if (len_pad < len || (off + len_pad) < off) | |
615 | return 0; | |
616 | ||
97d3d0f9 | 617 | ret = current->mm->get_unmapped_area(filp, addr, len_pad, |
74d2fad1 | 618 | off >> PAGE_SHIFT, flags); |
97d3d0f9 KS |
619 | |
620 | /* | |
621 | * The failure might be due to length padding. The caller will retry | |
622 | * without the padding. | |
623 | */ | |
624 | if (IS_ERR_VALUE(ret)) | |
74d2fad1 TK |
625 | return 0; |
626 | ||
97d3d0f9 KS |
627 | /* |
628 | * Do not try to align to THP boundary if allocation at the address | |
629 | * hint succeeds. | |
630 | */ | |
631 | if (ret == addr) | |
632 | return addr; | |
633 | ||
634 | ret += (off - ret) & (size - 1); | |
635 | return ret; | |
74d2fad1 TK |
636 | } |
637 | ||
638 | unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, | |
639 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
640 | { | |
97d3d0f9 | 641 | unsigned long ret; |
74d2fad1 TK |
642 | loff_t off = (loff_t)pgoff << PAGE_SHIFT; |
643 | ||
97d3d0f9 KS |
644 | ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE); |
645 | if (ret) | |
646 | return ret; | |
1854bc6e | 647 | |
74d2fad1 TK |
648 | return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); |
649 | } | |
650 | EXPORT_SYMBOL_GPL(thp_get_unmapped_area); | |
651 | ||
2b740303 SJ |
652 | static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, |
653 | struct page *page, gfp_t gfp) | |
71e3aac0 | 654 | { |
82b0f8c3 | 655 | struct vm_area_struct *vma = vmf->vma; |
71e3aac0 | 656 | pgtable_t pgtable; |
82b0f8c3 | 657 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
2b740303 | 658 | vm_fault_t ret = 0; |
71e3aac0 | 659 | |
309381fe | 660 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
00501b53 | 661 | |
8f425e4e | 662 | if (mem_cgroup_charge(page_folio(page), vma->vm_mm, gfp)) { |
6b251fc9 AA |
663 | put_page(page); |
664 | count_vm_event(THP_FAULT_FALLBACK); | |
85b9f46e | 665 | count_vm_event(THP_FAULT_FALLBACK_CHARGE); |
6b251fc9 AA |
666 | return VM_FAULT_FALLBACK; |
667 | } | |
9d82c694 | 668 | cgroup_throttle_swaprate(page, gfp); |
00501b53 | 669 | |
4cf58924 | 670 | pgtable = pte_alloc_one(vma->vm_mm); |
00501b53 | 671 | if (unlikely(!pgtable)) { |
6b31d595 MH |
672 | ret = VM_FAULT_OOM; |
673 | goto release; | |
00501b53 | 674 | } |
71e3aac0 | 675 | |
c79b57e4 | 676 | clear_huge_page(page, vmf->address, HPAGE_PMD_NR); |
52f37629 MK |
677 | /* |
678 | * The memory barrier inside __SetPageUptodate makes sure that | |
679 | * clear_huge_page writes become visible before the set_pmd_at() | |
680 | * write. | |
681 | */ | |
71e3aac0 AA |
682 | __SetPageUptodate(page); |
683 | ||
82b0f8c3 JK |
684 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
685 | if (unlikely(!pmd_none(*vmf->pmd))) { | |
6b31d595 | 686 | goto unlock_release; |
71e3aac0 AA |
687 | } else { |
688 | pmd_t entry; | |
6b251fc9 | 689 | |
6b31d595 MH |
690 | ret = check_stable_address_space(vma->vm_mm); |
691 | if (ret) | |
692 | goto unlock_release; | |
693 | ||
6b251fc9 AA |
694 | /* Deliver the page fault to userland */ |
695 | if (userfaultfd_missing(vma)) { | |
82b0f8c3 | 696 | spin_unlock(vmf->ptl); |
6b251fc9 | 697 | put_page(page); |
bae473a4 | 698 | pte_free(vma->vm_mm, pgtable); |
8fd5eda4 ML |
699 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
700 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); | |
701 | return ret; | |
6b251fc9 AA |
702 | } |
703 | ||
3122359a | 704 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
f55e1014 | 705 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
40f2bbf7 | 706 | page_add_new_anon_rmap(page, vma, haddr); |
b518154e | 707 | lru_cache_add_inactive_or_unevictable(page, vma); |
82b0f8c3 JK |
708 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); |
709 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); | |
fca40573 | 710 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
bae473a4 | 711 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
c4812909 | 712 | mm_inc_nr_ptes(vma->vm_mm); |
82b0f8c3 | 713 | spin_unlock(vmf->ptl); |
6b251fc9 | 714 | count_vm_event(THP_FAULT_ALLOC); |
9d82c694 | 715 | count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); |
71e3aac0 AA |
716 | } |
717 | ||
aa2e878e | 718 | return 0; |
6b31d595 MH |
719 | unlock_release: |
720 | spin_unlock(vmf->ptl); | |
721 | release: | |
722 | if (pgtable) | |
723 | pte_free(vma->vm_mm, pgtable); | |
6b31d595 MH |
724 | put_page(page); |
725 | return ret; | |
726 | ||
71e3aac0 AA |
727 | } |
728 | ||
444eb2a4 | 729 | /* |
21440d7e DR |
730 | * always: directly stall for all thp allocations |
731 | * defer: wake kswapd and fail if not immediately available | |
732 | * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise | |
733 | * fail if not immediately available | |
734 | * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately | |
735 | * available | |
736 | * never: never stall for any thp allocation | |
444eb2a4 | 737 | */ |
164cc4fe | 738 | gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma) |
444eb2a4 | 739 | { |
164cc4fe | 740 | const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE); |
2f0799a0 | 741 | |
ac79f78d | 742 | /* Always do synchronous compaction */ |
a8282608 AA |
743 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags)) |
744 | return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY); | |
ac79f78d DR |
745 | |
746 | /* Kick kcompactd and fail quickly */ | |
21440d7e | 747 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags)) |
19deb769 | 748 | return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM; |
ac79f78d DR |
749 | |
750 | /* Synchronous compaction if madvised, otherwise kick kcompactd */ | |
21440d7e | 751 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
752 | return GFP_TRANSHUGE_LIGHT | |
753 | (vma_madvised ? __GFP_DIRECT_RECLAIM : | |
754 | __GFP_KSWAPD_RECLAIM); | |
ac79f78d DR |
755 | |
756 | /* Only do synchronous compaction if madvised */ | |
21440d7e | 757 | if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags)) |
19deb769 DR |
758 | return GFP_TRANSHUGE_LIGHT | |
759 | (vma_madvised ? __GFP_DIRECT_RECLAIM : 0); | |
ac79f78d | 760 | |
19deb769 | 761 | return GFP_TRANSHUGE_LIGHT; |
444eb2a4 MG |
762 | } |
763 | ||
c4088ebd | 764 | /* Caller must hold page table lock. */ |
2efeb8da | 765 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 766 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 767 | struct page *zero_page) |
fc9fe822 KS |
768 | { |
769 | pmd_t entry; | |
7c414164 | 770 | if (!pmd_none(*pmd)) |
2efeb8da | 771 | return; |
5918d10a | 772 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 | 773 | entry = pmd_mkhuge(entry); |
c8bb4163 | 774 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 775 | set_pmd_at(mm, haddr, pmd, entry); |
c4812909 | 776 | mm_inc_nr_ptes(mm); |
fc9fe822 KS |
777 | } |
778 | ||
2b740303 | 779 | vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) |
71e3aac0 | 780 | { |
82b0f8c3 | 781 | struct vm_area_struct *vma = vmf->vma; |
077fcf11 | 782 | gfp_t gfp; |
cb196ee1 | 783 | struct folio *folio; |
82b0f8c3 | 784 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
71e3aac0 | 785 | |
43675e6f | 786 | if (!transhuge_vma_suitable(vma, haddr)) |
c0292554 | 787 | return VM_FAULT_FALLBACK; |
128ec037 KS |
788 | if (unlikely(anon_vma_prepare(vma))) |
789 | return VM_FAULT_OOM; | |
4fa6893f | 790 | khugepaged_enter_vma(vma, vma->vm_flags); |
d2081b2b | 791 | |
82b0f8c3 | 792 | if (!(vmf->flags & FAULT_FLAG_WRITE) && |
bae473a4 | 793 | !mm_forbids_zeropage(vma->vm_mm) && |
128ec037 KS |
794 | transparent_hugepage_use_zero_page()) { |
795 | pgtable_t pgtable; | |
796 | struct page *zero_page; | |
2b740303 | 797 | vm_fault_t ret; |
4cf58924 | 798 | pgtable = pte_alloc_one(vma->vm_mm); |
128ec037 | 799 | if (unlikely(!pgtable)) |
ba76149f | 800 | return VM_FAULT_OOM; |
6fcb52a5 | 801 | zero_page = mm_get_huge_zero_page(vma->vm_mm); |
128ec037 | 802 | if (unlikely(!zero_page)) { |
bae473a4 | 803 | pte_free(vma->vm_mm, pgtable); |
81ab4201 | 804 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 805 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 806 | } |
82b0f8c3 | 807 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
6b251fc9 | 808 | ret = 0; |
82b0f8c3 | 809 | if (pmd_none(*vmf->pmd)) { |
6b31d595 MH |
810 | ret = check_stable_address_space(vma->vm_mm); |
811 | if (ret) { | |
812 | spin_unlock(vmf->ptl); | |
bfe8cc1d | 813 | pte_free(vma->vm_mm, pgtable); |
6b31d595 | 814 | } else if (userfaultfd_missing(vma)) { |
82b0f8c3 | 815 | spin_unlock(vmf->ptl); |
bfe8cc1d | 816 | pte_free(vma->vm_mm, pgtable); |
82b0f8c3 | 817 | ret = handle_userfault(vmf, VM_UFFD_MISSING); |
6b251fc9 AA |
818 | VM_BUG_ON(ret & VM_FAULT_FALLBACK); |
819 | } else { | |
bae473a4 | 820 | set_huge_zero_page(pgtable, vma->vm_mm, vma, |
82b0f8c3 | 821 | haddr, vmf->pmd, zero_page); |
fca40573 | 822 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 823 | spin_unlock(vmf->ptl); |
6b251fc9 | 824 | } |
bfe8cc1d | 825 | } else { |
82b0f8c3 | 826 | spin_unlock(vmf->ptl); |
bae473a4 | 827 | pte_free(vma->vm_mm, pgtable); |
bfe8cc1d | 828 | } |
6b251fc9 | 829 | return ret; |
71e3aac0 | 830 | } |
164cc4fe | 831 | gfp = vma_thp_gfp_mask(vma); |
cb196ee1 MWO |
832 | folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); |
833 | if (unlikely(!folio)) { | |
128ec037 | 834 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 835 | return VM_FAULT_FALLBACK; |
128ec037 | 836 | } |
cb196ee1 | 837 | return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); |
71e3aac0 AA |
838 | } |
839 | ||
ae18d6dc | 840 | static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, |
3b6521f5 OH |
841 | pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write, |
842 | pgtable_t pgtable) | |
5cad465d MW |
843 | { |
844 | struct mm_struct *mm = vma->vm_mm; | |
845 | pmd_t entry; | |
846 | spinlock_t *ptl; | |
847 | ||
848 | ptl = pmd_lock(mm, pmd); | |
c6f3c5ee AK |
849 | if (!pmd_none(*pmd)) { |
850 | if (write) { | |
851 | if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { | |
852 | WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); | |
853 | goto out_unlock; | |
854 | } | |
855 | entry = pmd_mkyoung(*pmd); | |
856 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
857 | if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) | |
858 | update_mmu_cache_pmd(vma, addr, pmd); | |
859 | } | |
860 | ||
861 | goto out_unlock; | |
862 | } | |
863 | ||
f25748e3 DW |
864 | entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); |
865 | if (pfn_t_devmap(pfn)) | |
866 | entry = pmd_mkdevmap(entry); | |
01871e59 | 867 | if (write) { |
f55e1014 LT |
868 | entry = pmd_mkyoung(pmd_mkdirty(entry)); |
869 | entry = maybe_pmd_mkwrite(entry, vma); | |
5cad465d | 870 | } |
3b6521f5 OH |
871 | |
872 | if (pgtable) { | |
873 | pgtable_trans_huge_deposit(mm, pmd, pgtable); | |
c4812909 | 874 | mm_inc_nr_ptes(mm); |
c6f3c5ee | 875 | pgtable = NULL; |
3b6521f5 OH |
876 | } |
877 | ||
01871e59 RZ |
878 | set_pmd_at(mm, addr, pmd, entry); |
879 | update_mmu_cache_pmd(vma, addr, pmd); | |
c6f3c5ee AK |
880 | |
881 | out_unlock: | |
5cad465d | 882 | spin_unlock(ptl); |
c6f3c5ee AK |
883 | if (pgtable) |
884 | pte_free(mm, pgtable); | |
5cad465d MW |
885 | } |
886 | ||
9a9731b1 THV |
887 | /** |
888 | * vmf_insert_pfn_pmd_prot - insert a pmd size pfn | |
889 | * @vmf: Structure describing the fault | |
890 | * @pfn: pfn to insert | |
891 | * @pgprot: page protection to use | |
892 | * @write: whether it's a write fault | |
893 | * | |
894 | * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and | |
895 | * also consult the vmf_insert_mixed_prot() documentation when | |
896 | * @pgprot != @vmf->vma->vm_page_prot. | |
897 | * | |
898 | * Return: vm_fault_t value. | |
899 | */ | |
900 | vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn, | |
901 | pgprot_t pgprot, bool write) | |
5cad465d | 902 | { |
fce86ff5 DW |
903 | unsigned long addr = vmf->address & PMD_MASK; |
904 | struct vm_area_struct *vma = vmf->vma; | |
3b6521f5 | 905 | pgtable_t pgtable = NULL; |
fce86ff5 | 906 | |
5cad465d MW |
907 | /* |
908 | * If we had pmd_special, we could avoid all these restrictions, | |
909 | * but we need to be consistent with PTEs and architectures that | |
910 | * can't support a 'special' bit. | |
911 | */ | |
e1fb4a08 DJ |
912 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
913 | !pfn_t_devmap(pfn)); | |
5cad465d MW |
914 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
915 | (VM_PFNMAP|VM_MIXEDMAP)); | |
916 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
5cad465d MW |
917 | |
918 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
919 | return VM_FAULT_SIGBUS; | |
308a047c | 920 | |
3b6521f5 | 921 | if (arch_needs_pgtable_deposit()) { |
4cf58924 | 922 | pgtable = pte_alloc_one(vma->vm_mm); |
3b6521f5 OH |
923 | if (!pgtable) |
924 | return VM_FAULT_OOM; | |
925 | } | |
926 | ||
308a047c BP |
927 | track_pfn_insert(vma, &pgprot, pfn); |
928 | ||
fce86ff5 | 929 | insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); |
ae18d6dc | 930 | return VM_FAULT_NOPAGE; |
5cad465d | 931 | } |
9a9731b1 | 932 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot); |
5cad465d | 933 | |
a00cc7d9 | 934 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
f55e1014 | 935 | static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) |
a00cc7d9 | 936 | { |
f55e1014 | 937 | if (likely(vma->vm_flags & VM_WRITE)) |
a00cc7d9 MW |
938 | pud = pud_mkwrite(pud); |
939 | return pud; | |
940 | } | |
941 | ||
942 | static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, | |
943 | pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) | |
944 | { | |
945 | struct mm_struct *mm = vma->vm_mm; | |
946 | pud_t entry; | |
947 | spinlock_t *ptl; | |
948 | ||
949 | ptl = pud_lock(mm, pud); | |
c6f3c5ee AK |
950 | if (!pud_none(*pud)) { |
951 | if (write) { | |
952 | if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { | |
953 | WARN_ON_ONCE(!is_huge_zero_pud(*pud)); | |
954 | goto out_unlock; | |
955 | } | |
956 | entry = pud_mkyoung(*pud); | |
957 | entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); | |
958 | if (pudp_set_access_flags(vma, addr, pud, entry, 1)) | |
959 | update_mmu_cache_pud(vma, addr, pud); | |
960 | } | |
961 | goto out_unlock; | |
962 | } | |
963 | ||
a00cc7d9 MW |
964 | entry = pud_mkhuge(pfn_t_pud(pfn, prot)); |
965 | if (pfn_t_devmap(pfn)) | |
966 | entry = pud_mkdevmap(entry); | |
967 | if (write) { | |
f55e1014 LT |
968 | entry = pud_mkyoung(pud_mkdirty(entry)); |
969 | entry = maybe_pud_mkwrite(entry, vma); | |
a00cc7d9 MW |
970 | } |
971 | set_pud_at(mm, addr, pud, entry); | |
972 | update_mmu_cache_pud(vma, addr, pud); | |
c6f3c5ee AK |
973 | |
974 | out_unlock: | |
a00cc7d9 MW |
975 | spin_unlock(ptl); |
976 | } | |
977 | ||
9a9731b1 THV |
978 | /** |
979 | * vmf_insert_pfn_pud_prot - insert a pud size pfn | |
980 | * @vmf: Structure describing the fault | |
981 | * @pfn: pfn to insert | |
982 | * @pgprot: page protection to use | |
983 | * @write: whether it's a write fault | |
984 | * | |
985 | * Insert a pud size pfn. See vmf_insert_pfn() for additional info and | |
986 | * also consult the vmf_insert_mixed_prot() documentation when | |
987 | * @pgprot != @vmf->vma->vm_page_prot. | |
988 | * | |
989 | * Return: vm_fault_t value. | |
990 | */ | |
991 | vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, | |
992 | pgprot_t pgprot, bool write) | |
a00cc7d9 | 993 | { |
fce86ff5 DW |
994 | unsigned long addr = vmf->address & PUD_MASK; |
995 | struct vm_area_struct *vma = vmf->vma; | |
fce86ff5 | 996 | |
a00cc7d9 MW |
997 | /* |
998 | * If we had pud_special, we could avoid all these restrictions, | |
999 | * but we need to be consistent with PTEs and architectures that | |
1000 | * can't support a 'special' bit. | |
1001 | */ | |
62ec0d8c DJ |
1002 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && |
1003 | !pfn_t_devmap(pfn)); | |
a00cc7d9 MW |
1004 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == |
1005 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1006 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
a00cc7d9 MW |
1007 | |
1008 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1009 | return VM_FAULT_SIGBUS; | |
1010 | ||
1011 | track_pfn_insert(vma, &pgprot, pfn); | |
1012 | ||
fce86ff5 | 1013 | insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); |
a00cc7d9 MW |
1014 | return VM_FAULT_NOPAGE; |
1015 | } | |
9a9731b1 | 1016 | EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot); |
a00cc7d9 MW |
1017 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
1018 | ||
3565fce3 | 1019 | static void touch_pmd(struct vm_area_struct *vma, unsigned long addr, |
a69e4717 | 1020 | pmd_t *pmd, bool write) |
3565fce3 DW |
1021 | { |
1022 | pmd_t _pmd; | |
1023 | ||
a8f97366 | 1024 | _pmd = pmd_mkyoung(*pmd); |
a69e4717 | 1025 | if (write) |
a8f97366 | 1026 | _pmd = pmd_mkdirty(_pmd); |
3565fce3 | 1027 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
a69e4717 | 1028 | pmd, _pmd, write)) |
3565fce3 DW |
1029 | update_mmu_cache_pmd(vma, addr, pmd); |
1030 | } | |
1031 | ||
1032 | struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1033 | pmd_t *pmd, int flags, struct dev_pagemap **pgmap) |
3565fce3 DW |
1034 | { |
1035 | unsigned long pfn = pmd_pfn(*pmd); | |
1036 | struct mm_struct *mm = vma->vm_mm; | |
3565fce3 | 1037 | struct page *page; |
0f089235 | 1038 | int ret; |
3565fce3 DW |
1039 | |
1040 | assert_spin_locked(pmd_lockptr(mm, pmd)); | |
1041 | ||
3faa52c0 JH |
1042 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1043 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1044 | (FOLL_PIN | FOLL_GET))) | |
1045 | return NULL; | |
1046 | ||
f6f37321 | 1047 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) |
3565fce3 DW |
1048 | return NULL; |
1049 | ||
1050 | if (pmd_present(*pmd) && pmd_devmap(*pmd)) | |
1051 | /* pass */; | |
1052 | else | |
1053 | return NULL; | |
1054 | ||
1055 | if (flags & FOLL_TOUCH) | |
a69e4717 | 1056 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3565fce3 DW |
1057 | |
1058 | /* | |
1059 | * device mapped pages can only be returned if the | |
1060 | * caller will manage the page reference count. | |
1061 | */ | |
3faa52c0 | 1062 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
3565fce3 DW |
1063 | return ERR_PTR(-EEXIST); |
1064 | ||
1065 | pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1066 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1067 | if (!*pgmap) | |
3565fce3 DW |
1068 | return ERR_PTR(-EFAULT); |
1069 | page = pfn_to_page(pfn); | |
0f089235 LG |
1070 | ret = try_grab_page(page, flags); |
1071 | if (ret) | |
1072 | page = ERR_PTR(ret); | |
3565fce3 DW |
1073 | |
1074 | return page; | |
1075 | } | |
1076 | ||
71e3aac0 AA |
1077 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
1078 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
8f34f1ea | 1079 | struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) |
71e3aac0 | 1080 | { |
c4088ebd | 1081 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
1082 | struct page *src_page; |
1083 | pmd_t pmd; | |
12c9d70b | 1084 | pgtable_t pgtable = NULL; |
628d47ce | 1085 | int ret = -ENOMEM; |
71e3aac0 | 1086 | |
628d47ce | 1087 | /* Skip if can be re-fill on fault */ |
8f34f1ea | 1088 | if (!vma_is_anonymous(dst_vma)) |
628d47ce KS |
1089 | return 0; |
1090 | ||
4cf58924 | 1091 | pgtable = pte_alloc_one(dst_mm); |
628d47ce KS |
1092 | if (unlikely(!pgtable)) |
1093 | goto out; | |
71e3aac0 | 1094 | |
c4088ebd KS |
1095 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
1096 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
1097 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
1098 | |
1099 | ret = -EAGAIN; | |
1100 | pmd = *src_pmd; | |
84c3fc4e ZY |
1101 | |
1102 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
1103 | if (unlikely(is_swap_pmd(pmd))) { | |
1104 | swp_entry_t entry = pmd_to_swp_entry(pmd); | |
1105 | ||
1106 | VM_BUG_ON(!is_pmd_migration_entry(pmd)); | |
6c287605 | 1107 | if (!is_readable_migration_entry(entry)) { |
4dd845b5 AP |
1108 | entry = make_readable_migration_entry( |
1109 | swp_offset(entry)); | |
84c3fc4e | 1110 | pmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1111 | if (pmd_swp_soft_dirty(*src_pmd)) |
1112 | pmd = pmd_swp_mksoft_dirty(pmd); | |
8f34f1ea PX |
1113 | if (pmd_swp_uffd_wp(*src_pmd)) |
1114 | pmd = pmd_swp_mkuffd_wp(pmd); | |
84c3fc4e ZY |
1115 | set_pmd_at(src_mm, addr, src_pmd, pmd); |
1116 | } | |
dd8a67f9 | 1117 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
af5b0f6a | 1118 | mm_inc_nr_ptes(dst_mm); |
dd8a67f9 | 1119 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
8f34f1ea PX |
1120 | if (!userfaultfd_wp(dst_vma)) |
1121 | pmd = pmd_swp_clear_uffd_wp(pmd); | |
84c3fc4e ZY |
1122 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1123 | ret = 0; | |
1124 | goto out_unlock; | |
1125 | } | |
1126 | #endif | |
1127 | ||
628d47ce | 1128 | if (unlikely(!pmd_trans_huge(pmd))) { |
71e3aac0 AA |
1129 | pte_free(dst_mm, pgtable); |
1130 | goto out_unlock; | |
1131 | } | |
fc9fe822 | 1132 | /* |
c4088ebd | 1133 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
1134 | * under splitting since we don't split the page itself, only pmd to |
1135 | * a page table. | |
1136 | */ | |
1137 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 KS |
1138 | /* |
1139 | * get_huge_zero_page() will never allocate a new page here, | |
1140 | * since we already have a zero page to copy. It just takes a | |
1141 | * reference. | |
1142 | */ | |
5fc7a5f6 PX |
1143 | mm_get_huge_zero_page(dst_mm); |
1144 | goto out_zero_page; | |
fc9fe822 | 1145 | } |
de466bd6 | 1146 | |
628d47ce KS |
1147 | src_page = pmd_page(pmd); |
1148 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); | |
d042035e | 1149 | |
fb3d824d DH |
1150 | get_page(src_page); |
1151 | if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { | |
1152 | /* Page maybe pinned: split and retry the fault on PTEs. */ | |
1153 | put_page(src_page); | |
d042035e PX |
1154 | pte_free(dst_mm, pgtable); |
1155 | spin_unlock(src_ptl); | |
1156 | spin_unlock(dst_ptl); | |
8f34f1ea | 1157 | __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); |
d042035e PX |
1158 | return -EAGAIN; |
1159 | } | |
628d47ce | 1160 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); |
5fc7a5f6 | 1161 | out_zero_page: |
c4812909 | 1162 | mm_inc_nr_ptes(dst_mm); |
628d47ce | 1163 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 1164 | pmdp_set_wrprotect(src_mm, addr, src_pmd); |
8f34f1ea PX |
1165 | if (!userfaultfd_wp(dst_vma)) |
1166 | pmd = pmd_clear_uffd_wp(pmd); | |
71e3aac0 AA |
1167 | pmd = pmd_mkold(pmd_wrprotect(pmd)); |
1168 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
71e3aac0 AA |
1169 | |
1170 | ret = 0; | |
1171 | out_unlock: | |
c4088ebd KS |
1172 | spin_unlock(src_ptl); |
1173 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
1174 | out: |
1175 | return ret; | |
1176 | } | |
1177 | ||
a00cc7d9 MW |
1178 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
1179 | static void touch_pud(struct vm_area_struct *vma, unsigned long addr, | |
5fe653e9 | 1180 | pud_t *pud, bool write) |
a00cc7d9 MW |
1181 | { |
1182 | pud_t _pud; | |
1183 | ||
a8f97366 | 1184 | _pud = pud_mkyoung(*pud); |
5fe653e9 | 1185 | if (write) |
a8f97366 | 1186 | _pud = pud_mkdirty(_pud); |
a00cc7d9 | 1187 | if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK, |
5fe653e9 | 1188 | pud, _pud, write)) |
a00cc7d9 MW |
1189 | update_mmu_cache_pud(vma, addr, pud); |
1190 | } | |
1191 | ||
1192 | struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, | |
df06b37f | 1193 | pud_t *pud, int flags, struct dev_pagemap **pgmap) |
a00cc7d9 MW |
1194 | { |
1195 | unsigned long pfn = pud_pfn(*pud); | |
1196 | struct mm_struct *mm = vma->vm_mm; | |
a00cc7d9 | 1197 | struct page *page; |
0f089235 | 1198 | int ret; |
a00cc7d9 MW |
1199 | |
1200 | assert_spin_locked(pud_lockptr(mm, pud)); | |
1201 | ||
f6f37321 | 1202 | if (flags & FOLL_WRITE && !pud_write(*pud)) |
a00cc7d9 MW |
1203 | return NULL; |
1204 | ||
3faa52c0 JH |
1205 | /* FOLL_GET and FOLL_PIN are mutually exclusive. */ |
1206 | if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == | |
1207 | (FOLL_PIN | FOLL_GET))) | |
1208 | return NULL; | |
1209 | ||
a00cc7d9 MW |
1210 | if (pud_present(*pud) && pud_devmap(*pud)) |
1211 | /* pass */; | |
1212 | else | |
1213 | return NULL; | |
1214 | ||
1215 | if (flags & FOLL_TOUCH) | |
5fe653e9 | 1216 | touch_pud(vma, addr, pud, flags & FOLL_WRITE); |
a00cc7d9 MW |
1217 | |
1218 | /* | |
1219 | * device mapped pages can only be returned if the | |
1220 | * caller will manage the page reference count. | |
3faa52c0 JH |
1221 | * |
1222 | * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here: | |
a00cc7d9 | 1223 | */ |
3faa52c0 | 1224 | if (!(flags & (FOLL_GET | FOLL_PIN))) |
a00cc7d9 MW |
1225 | return ERR_PTR(-EEXIST); |
1226 | ||
1227 | pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; | |
df06b37f KB |
1228 | *pgmap = get_dev_pagemap(pfn, *pgmap); |
1229 | if (!*pgmap) | |
a00cc7d9 MW |
1230 | return ERR_PTR(-EFAULT); |
1231 | page = pfn_to_page(pfn); | |
0f089235 LG |
1232 | |
1233 | ret = try_grab_page(page, flags); | |
1234 | if (ret) | |
1235 | page = ERR_PTR(ret); | |
a00cc7d9 MW |
1236 | |
1237 | return page; | |
1238 | } | |
1239 | ||
1240 | int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1241 | pud_t *dst_pud, pud_t *src_pud, unsigned long addr, | |
1242 | struct vm_area_struct *vma) | |
1243 | { | |
1244 | spinlock_t *dst_ptl, *src_ptl; | |
1245 | pud_t pud; | |
1246 | int ret; | |
1247 | ||
1248 | dst_ptl = pud_lock(dst_mm, dst_pud); | |
1249 | src_ptl = pud_lockptr(src_mm, src_pud); | |
1250 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
1251 | ||
1252 | ret = -EAGAIN; | |
1253 | pud = *src_pud; | |
1254 | if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud))) | |
1255 | goto out_unlock; | |
1256 | ||
1257 | /* | |
1258 | * When page table lock is held, the huge zero pud should not be | |
1259 | * under splitting since we don't split the page itself, only pud to | |
1260 | * a page table. | |
1261 | */ | |
1262 | if (is_huge_zero_pud(pud)) { | |
1263 | /* No huge zero pud yet */ | |
1264 | } | |
1265 | ||
fb3d824d DH |
1266 | /* |
1267 | * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() | |
1268 | * and split if duplicating fails. | |
1269 | */ | |
a00cc7d9 MW |
1270 | pudp_set_wrprotect(src_mm, addr, src_pud); |
1271 | pud = pud_mkold(pud_wrprotect(pud)); | |
1272 | set_pud_at(dst_mm, addr, dst_pud, pud); | |
1273 | ||
1274 | ret = 0; | |
1275 | out_unlock: | |
1276 | spin_unlock(src_ptl); | |
1277 | spin_unlock(dst_ptl); | |
1278 | return ret; | |
1279 | } | |
1280 | ||
1281 | void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud) | |
1282 | { | |
a00cc7d9 MW |
1283 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
1284 | ||
1285 | vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud); | |
1286 | if (unlikely(!pud_same(*vmf->pud, orig_pud))) | |
1287 | goto unlock; | |
1288 | ||
5fe653e9 | 1289 | touch_pud(vmf->vma, vmf->address, vmf->pud, write); |
a00cc7d9 MW |
1290 | unlock: |
1291 | spin_unlock(vmf->ptl); | |
1292 | } | |
1293 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
1294 | ||
5db4f15c | 1295 | void huge_pmd_set_accessed(struct vm_fault *vmf) |
a1dd450b | 1296 | { |
20f664aa | 1297 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
a1dd450b | 1298 | |
82b0f8c3 | 1299 | vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
a69e4717 | 1300 | if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) |
a1dd450b WD |
1301 | goto unlock; |
1302 | ||
a69e4717 | 1303 | touch_pmd(vmf->vma, vmf->address, vmf->pmd, write); |
a1dd450b WD |
1304 | |
1305 | unlock: | |
82b0f8c3 | 1306 | spin_unlock(vmf->ptl); |
a1dd450b WD |
1307 | } |
1308 | ||
5db4f15c | 1309 | vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) |
71e3aac0 | 1310 | { |
c89357e2 | 1311 | const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; |
82b0f8c3 | 1312 | struct vm_area_struct *vma = vmf->vma; |
2fad3d14 | 1313 | struct folio *folio; |
3917c802 | 1314 | struct page *page; |
82b0f8c3 | 1315 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
5db4f15c | 1316 | pmd_t orig_pmd = vmf->orig_pmd; |
71e3aac0 | 1317 | |
82b0f8c3 | 1318 | vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); |
81d1b09c | 1319 | VM_BUG_ON_VMA(!vma->anon_vma, vma); |
3917c802 | 1320 | |
93b4796d | 1321 | if (is_huge_zero_pmd(orig_pmd)) |
3917c802 KS |
1322 | goto fallback; |
1323 | ||
82b0f8c3 | 1324 | spin_lock(vmf->ptl); |
3917c802 KS |
1325 | |
1326 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
1327 | spin_unlock(vmf->ptl); | |
1328 | return 0; | |
1329 | } | |
71e3aac0 AA |
1330 | |
1331 | page = pmd_page(orig_pmd); | |
2fad3d14 | 1332 | folio = page_folio(page); |
f6004e73 | 1333 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3917c802 | 1334 | |
6c287605 DH |
1335 | /* Early check when only holding the PT lock. */ |
1336 | if (PageAnonExclusive(page)) | |
1337 | goto reuse; | |
1338 | ||
2fad3d14 MWO |
1339 | if (!folio_trylock(folio)) { |
1340 | folio_get(folio); | |
ba3c4ce6 | 1341 | spin_unlock(vmf->ptl); |
2fad3d14 | 1342 | folio_lock(folio); |
ba3c4ce6 HY |
1343 | spin_lock(vmf->ptl); |
1344 | if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) { | |
3917c802 | 1345 | spin_unlock(vmf->ptl); |
2fad3d14 MWO |
1346 | folio_unlock(folio); |
1347 | folio_put(folio); | |
3917c802 | 1348 | return 0; |
ba3c4ce6 | 1349 | } |
2fad3d14 | 1350 | folio_put(folio); |
ba3c4ce6 | 1351 | } |
3917c802 | 1352 | |
6c287605 DH |
1353 | /* Recheck after temporarily dropping the PT lock. */ |
1354 | if (PageAnonExclusive(page)) { | |
2fad3d14 | 1355 | folio_unlock(folio); |
6c287605 DH |
1356 | goto reuse; |
1357 | } | |
1358 | ||
3917c802 | 1359 | /* |
2fad3d14 MWO |
1360 | * See do_wp_page(): we can only reuse the folio exclusively if |
1361 | * there are no additional references. Note that we always drain | |
1362 | * the LRU pagevecs immediately after adding a THP. | |
3917c802 | 1363 | */ |
2fad3d14 MWO |
1364 | if (folio_ref_count(folio) > |
1365 | 1 + folio_test_swapcache(folio) * folio_nr_pages(folio)) | |
3bff7e3f | 1366 | goto unlock_fallback; |
2fad3d14 MWO |
1367 | if (folio_test_swapcache(folio)) |
1368 | folio_free_swap(folio); | |
1369 | if (folio_ref_count(folio) == 1) { | |
71e3aac0 | 1370 | pmd_t entry; |
6c54dc6c DH |
1371 | |
1372 | page_move_anon_rmap(page, vma); | |
2fad3d14 | 1373 | folio_unlock(folio); |
6c287605 | 1374 | reuse: |
c89357e2 DH |
1375 | if (unlikely(unshare)) { |
1376 | spin_unlock(vmf->ptl); | |
1377 | return 0; | |
1378 | } | |
71e3aac0 | 1379 | entry = pmd_mkyoung(orig_pmd); |
f55e1014 | 1380 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); |
3917c802 | 1381 | if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) |
82b0f8c3 | 1382 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); |
82b0f8c3 | 1383 | spin_unlock(vmf->ptl); |
cb8d8633 | 1384 | return 0; |
71e3aac0 | 1385 | } |
3917c802 | 1386 | |
3bff7e3f | 1387 | unlock_fallback: |
2fad3d14 | 1388 | folio_unlock(folio); |
82b0f8c3 | 1389 | spin_unlock(vmf->ptl); |
3917c802 KS |
1390 | fallback: |
1391 | __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); | |
1392 | return VM_FAULT_FALLBACK; | |
71e3aac0 AA |
1393 | } |
1394 | ||
c27f479e DH |
1395 | static inline bool can_change_pmd_writable(struct vm_area_struct *vma, |
1396 | unsigned long addr, pmd_t pmd) | |
1397 | { | |
1398 | struct page *page; | |
1399 | ||
1400 | if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) | |
1401 | return false; | |
1402 | ||
1403 | /* Don't touch entries that are not even readable (NUMA hinting). */ | |
1404 | if (pmd_protnone(pmd)) | |
1405 | return false; | |
1406 | ||
1407 | /* Do we need write faults for softdirty tracking? */ | |
1408 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1409 | return false; | |
1410 | ||
1411 | /* Do we need write faults for uffd-wp tracking? */ | |
1412 | if (userfaultfd_huge_pmd_wp(vma, pmd)) | |
1413 | return false; | |
1414 | ||
1415 | if (!(vma->vm_flags & VM_SHARED)) { | |
1416 | /* See can_change_pte_writable(). */ | |
1417 | page = vm_normal_page_pmd(vma, addr, pmd); | |
1418 | return page && PageAnon(page) && PageAnonExclusive(page); | |
1419 | } | |
1420 | ||
1421 | /* See can_change_pte_writable(). */ | |
1422 | return pmd_dirty(pmd); | |
1423 | } | |
1424 | ||
5535be30 DH |
1425 | /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */ |
1426 | static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, | |
1427 | struct vm_area_struct *vma, | |
1428 | unsigned int flags) | |
8310d48b | 1429 | { |
5535be30 DH |
1430 | /* If the pmd is writable, we can write to the page. */ |
1431 | if (pmd_write(pmd)) | |
1432 | return true; | |
1433 | ||
1434 | /* Maybe FOLL_FORCE is set to override it? */ | |
1435 | if (!(flags & FOLL_FORCE)) | |
1436 | return false; | |
1437 | ||
1438 | /* But FOLL_FORCE has no effect on shared mappings */ | |
1439 | if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) | |
1440 | return false; | |
1441 | ||
1442 | /* ... or read-only private ones */ | |
1443 | if (!(vma->vm_flags & VM_MAYWRITE)) | |
1444 | return false; | |
1445 | ||
1446 | /* ... or already writable ones that just need to take a write fault */ | |
1447 | if (vma->vm_flags & VM_WRITE) | |
1448 | return false; | |
1449 | ||
1450 | /* | |
1451 | * See can_change_pte_writable(): we broke COW and could map the page | |
1452 | * writable if we have an exclusive anonymous page ... | |
1453 | */ | |
1454 | if (!page || !PageAnon(page) || !PageAnonExclusive(page)) | |
1455 | return false; | |
1456 | ||
1457 | /* ... and a write-fault isn't required for other reasons. */ | |
1458 | if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) | |
1459 | return false; | |
1460 | return !userfaultfd_huge_pmd_wp(vma, pmd); | |
8310d48b KF |
1461 | } |
1462 | ||
b676b293 | 1463 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1464 | unsigned long addr, |
1465 | pmd_t *pmd, | |
1466 | unsigned int flags) | |
1467 | { | |
b676b293 | 1468 | struct mm_struct *mm = vma->vm_mm; |
5535be30 | 1469 | struct page *page; |
0f089235 | 1470 | int ret; |
71e3aac0 | 1471 | |
c4088ebd | 1472 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 | 1473 | |
5535be30 DH |
1474 | page = pmd_page(*pmd); |
1475 | VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); | |
1476 | ||
1477 | if ((flags & FOLL_WRITE) && | |
1478 | !can_follow_write_pmd(*pmd, page, vma, flags)) | |
1479 | return NULL; | |
71e3aac0 | 1480 | |
85facf25 KS |
1481 | /* Avoid dumping huge zero page */ |
1482 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1483 | return ERR_PTR(-EFAULT); | |
1484 | ||
2b4847e7 | 1485 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
474098ed | 1486 | if (pmd_protnone(*pmd) && !gup_can_follow_protnone(flags)) |
5535be30 | 1487 | return NULL; |
3faa52c0 | 1488 | |
84209e87 | 1489 | if (!pmd_write(*pmd) && gup_must_unshare(vma, flags, page)) |
a7f22660 DH |
1490 | return ERR_PTR(-EMLINK); |
1491 | ||
b6a2619c DH |
1492 | VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && |
1493 | !PageAnonExclusive(page), page); | |
1494 | ||
0f089235 LG |
1495 | ret = try_grab_page(page, flags); |
1496 | if (ret) | |
1497 | return ERR_PTR(ret); | |
3faa52c0 | 1498 | |
3565fce3 | 1499 | if (flags & FOLL_TOUCH) |
a69e4717 | 1500 | touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); |
3faa52c0 | 1501 | |
71e3aac0 | 1502 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
ca120cf6 | 1503 | VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); |
71e3aac0 | 1504 | |
71e3aac0 AA |
1505 | return page; |
1506 | } | |
1507 | ||
d10e63f2 | 1508 | /* NUMA hinting page fault entry point for trans huge pmds */ |
5db4f15c | 1509 | vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) |
d10e63f2 | 1510 | { |
82b0f8c3 | 1511 | struct vm_area_struct *vma = vmf->vma; |
c5b5a3dd YS |
1512 | pmd_t oldpmd = vmf->orig_pmd; |
1513 | pmd_t pmd; | |
b32967ff | 1514 | struct page *page; |
82b0f8c3 | 1515 | unsigned long haddr = vmf->address & HPAGE_PMD_MASK; |
c5b5a3dd | 1516 | int page_nid = NUMA_NO_NODE; |
33024536 | 1517 | int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); |
6a56ccbc | 1518 | bool migrated = false, writable = false; |
6688cc05 | 1519 | int flags = 0; |
d10e63f2 | 1520 | |
82b0f8c3 | 1521 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
c5b5a3dd | 1522 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { |
82b0f8c3 | 1523 | spin_unlock(vmf->ptl); |
de466bd6 MG |
1524 | goto out; |
1525 | } | |
1526 | ||
c5b5a3dd | 1527 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); |
6a56ccbc DH |
1528 | |
1529 | /* | |
1530 | * Detect now whether the PMD could be writable; this information | |
1531 | * is only valid while holding the PT lock. | |
1532 | */ | |
1533 | writable = pmd_write(pmd); | |
1534 | if (!writable && vma_wants_manual_pte_write_upgrade(vma) && | |
1535 | can_change_pmd_writable(vma, vmf->address, pmd)) | |
1536 | writable = true; | |
1537 | ||
c5b5a3dd YS |
1538 | page = vm_normal_page_pmd(vma, haddr, pmd); |
1539 | if (!page) | |
1540 | goto out_map; | |
1541 | ||
1542 | /* See similar comment in do_numa_page for explanation */ | |
6a56ccbc | 1543 | if (!writable) |
c5b5a3dd YS |
1544 | flags |= TNF_NO_GROUP; |
1545 | ||
1546 | page_nid = page_to_nid(page); | |
33024536 HY |
1547 | /* |
1548 | * For memory tiering mode, cpupid of slow memory page is used | |
1549 | * to record page access time. So use default value. | |
1550 | */ | |
1551 | if (node_is_toptier(page_nid)) | |
1552 | last_cpupid = page_cpupid_last(page); | |
c5b5a3dd YS |
1553 | target_nid = numa_migrate_prep(page, vma, haddr, page_nid, |
1554 | &flags); | |
1555 | ||
1556 | if (target_nid == NUMA_NO_NODE) { | |
1557 | put_page(page); | |
1558 | goto out_map; | |
1559 | } | |
1560 | ||
82b0f8c3 | 1561 | spin_unlock(vmf->ptl); |
6a56ccbc | 1562 | writable = false; |
8b1b436d | 1563 | |
c5b5a3dd | 1564 | migrated = migrate_misplaced_page(page, vma, target_nid); |
6688cc05 PZ |
1565 | if (migrated) { |
1566 | flags |= TNF_MIGRATED; | |
8191acbd | 1567 | page_nid = target_nid; |
c5b5a3dd | 1568 | } else { |
074c2381 | 1569 | flags |= TNF_MIGRATE_FAIL; |
c5b5a3dd YS |
1570 | vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); |
1571 | if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) { | |
1572 | spin_unlock(vmf->ptl); | |
1573 | goto out; | |
1574 | } | |
1575 | goto out_map; | |
1576 | } | |
b8916634 MG |
1577 | |
1578 | out: | |
98fa15f3 | 1579 | if (page_nid != NUMA_NO_NODE) |
82b0f8c3 | 1580 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, |
9a8b300f | 1581 | flags); |
8191acbd | 1582 | |
d10e63f2 | 1583 | return 0; |
c5b5a3dd YS |
1584 | |
1585 | out_map: | |
1586 | /* Restore the PMD */ | |
1587 | pmd = pmd_modify(oldpmd, vma->vm_page_prot); | |
1588 | pmd = pmd_mkyoung(pmd); | |
6a56ccbc | 1589 | if (writable) |
c5b5a3dd YS |
1590 | pmd = pmd_mkwrite(pmd); |
1591 | set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd); | |
1592 | update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); | |
1593 | spin_unlock(vmf->ptl); | |
1594 | goto out; | |
d10e63f2 MG |
1595 | } |
1596 | ||
319904ad HY |
1597 | /* |
1598 | * Return true if we do MADV_FREE successfully on entire pmd page. | |
1599 | * Otherwise, return false. | |
1600 | */ | |
1601 | bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
b8d3c4c3 | 1602 | pmd_t *pmd, unsigned long addr, unsigned long next) |
b8d3c4c3 MK |
1603 | { |
1604 | spinlock_t *ptl; | |
1605 | pmd_t orig_pmd; | |
1606 | struct page *page; | |
1607 | struct mm_struct *mm = tlb->mm; | |
319904ad | 1608 | bool ret = false; |
b8d3c4c3 | 1609 | |
ed6a7935 | 1610 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1611 | |
b6ec57f4 KS |
1612 | ptl = pmd_trans_huge_lock(pmd, vma); |
1613 | if (!ptl) | |
25eedabe | 1614 | goto out_unlocked; |
b8d3c4c3 MK |
1615 | |
1616 | orig_pmd = *pmd; | |
319904ad | 1617 | if (is_huge_zero_pmd(orig_pmd)) |
b8d3c4c3 | 1618 | goto out; |
b8d3c4c3 | 1619 | |
84c3fc4e ZY |
1620 | if (unlikely(!pmd_present(orig_pmd))) { |
1621 | VM_BUG_ON(thp_migration_supported() && | |
1622 | !is_pmd_migration_entry(orig_pmd)); | |
1623 | goto out; | |
1624 | } | |
1625 | ||
b8d3c4c3 MK |
1626 | page = pmd_page(orig_pmd); |
1627 | /* | |
1628 | * If other processes are mapping this page, we couldn't discard | |
1629 | * the page unless they all do MADV_FREE so let's skip the page. | |
1630 | */ | |
babbbdd0 | 1631 | if (total_mapcount(page) != 1) |
b8d3c4c3 MK |
1632 | goto out; |
1633 | ||
1634 | if (!trylock_page(page)) | |
1635 | goto out; | |
1636 | ||
1637 | /* | |
1638 | * If user want to discard part-pages of THP, split it so MADV_FREE | |
1639 | * will deactivate only them. | |
1640 | */ | |
1641 | if (next - addr != HPAGE_PMD_SIZE) { | |
1642 | get_page(page); | |
1643 | spin_unlock(ptl); | |
9818b8cd | 1644 | split_huge_page(page); |
b8d3c4c3 | 1645 | unlock_page(page); |
bbf29ffc | 1646 | put_page(page); |
b8d3c4c3 MK |
1647 | goto out_unlocked; |
1648 | } | |
1649 | ||
1650 | if (PageDirty(page)) | |
1651 | ClearPageDirty(page); | |
1652 | unlock_page(page); | |
1653 | ||
b8d3c4c3 | 1654 | if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) { |
58ceeb6b | 1655 | pmdp_invalidate(vma, addr, pmd); |
b8d3c4c3 MK |
1656 | orig_pmd = pmd_mkold(orig_pmd); |
1657 | orig_pmd = pmd_mkclean(orig_pmd); | |
1658 | ||
1659 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
1660 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
1661 | } | |
802a3a92 SL |
1662 | |
1663 | mark_page_lazyfree(page); | |
319904ad | 1664 | ret = true; |
b8d3c4c3 MK |
1665 | out: |
1666 | spin_unlock(ptl); | |
1667 | out_unlocked: | |
1668 | return ret; | |
1669 | } | |
1670 | ||
953c66c2 AK |
1671 | static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) |
1672 | { | |
1673 | pgtable_t pgtable; | |
1674 | ||
1675 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
1676 | pte_free(mm, pgtable); | |
c4812909 | 1677 | mm_dec_nr_ptes(mm); |
953c66c2 AK |
1678 | } |
1679 | ||
71e3aac0 | 1680 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1681 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1682 | { |
da146769 | 1683 | pmd_t orig_pmd; |
bf929152 | 1684 | spinlock_t *ptl; |
71e3aac0 | 1685 | |
ed6a7935 | 1686 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
07e32661 | 1687 | |
b6ec57f4 KS |
1688 | ptl = __pmd_trans_huge_lock(pmd, vma); |
1689 | if (!ptl) | |
da146769 KS |
1690 | return 0; |
1691 | /* | |
1692 | * For architectures like ppc64 we look at deposited pgtable | |
1693 | * when calling pmdp_huge_get_and_clear. So do the | |
1694 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1695 | * operations. | |
1696 | */ | |
93a98695 AK |
1697 | orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd, |
1698 | tlb->fullmm); | |
da146769 | 1699 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
2484ca9b | 1700 | if (vma_is_special_huge(vma)) { |
3b6521f5 OH |
1701 | if (arch_needs_pgtable_deposit()) |
1702 | zap_deposited_table(tlb->mm, pmd); | |
da146769 | 1703 | spin_unlock(ptl); |
da146769 | 1704 | } else if (is_huge_zero_pmd(orig_pmd)) { |
c14a6eb4 | 1705 | zap_deposited_table(tlb->mm, pmd); |
da146769 | 1706 | spin_unlock(ptl); |
da146769 | 1707 | } else { |
616b8371 ZY |
1708 | struct page *page = NULL; |
1709 | int flush_needed = 1; | |
1710 | ||
1711 | if (pmd_present(orig_pmd)) { | |
1712 | page = pmd_page(orig_pmd); | |
cea86fe2 | 1713 | page_remove_rmap(page, vma, true); |
616b8371 ZY |
1714 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
1715 | VM_BUG_ON_PAGE(!PageHead(page), page); | |
1716 | } else if (thp_migration_supported()) { | |
1717 | swp_entry_t entry; | |
1718 | ||
1719 | VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); | |
1720 | entry = pmd_to_swp_entry(orig_pmd); | |
af5cdaf8 | 1721 | page = pfn_swap_entry_to_page(entry); |
616b8371 ZY |
1722 | flush_needed = 0; |
1723 | } else | |
1724 | WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); | |
1725 | ||
b5072380 | 1726 | if (PageAnon(page)) { |
c14a6eb4 | 1727 | zap_deposited_table(tlb->mm, pmd); |
b5072380 KS |
1728 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
1729 | } else { | |
953c66c2 AK |
1730 | if (arch_needs_pgtable_deposit()) |
1731 | zap_deposited_table(tlb->mm, pmd); | |
fadae295 | 1732 | add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR); |
b5072380 | 1733 | } |
616b8371 | 1734 | |
da146769 | 1735 | spin_unlock(ptl); |
616b8371 ZY |
1736 | if (flush_needed) |
1737 | tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE); | |
025c5b24 | 1738 | } |
da146769 | 1739 | return 1; |
71e3aac0 AA |
1740 | } |
1741 | ||
1dd38b6c AK |
1742 | #ifndef pmd_move_must_withdraw |
1743 | static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, | |
1744 | spinlock_t *old_pmd_ptl, | |
1745 | struct vm_area_struct *vma) | |
1746 | { | |
1747 | /* | |
1748 | * With split pmd lock we also need to move preallocated | |
1749 | * PTE page table if new_pmd is on different PMD page table. | |
1750 | * | |
1751 | * We also don't deposit and withdraw tables for file pages. | |
1752 | */ | |
1753 | return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma); | |
1754 | } | |
1755 | #endif | |
1756 | ||
ab6e3d09 NH |
1757 | static pmd_t move_soft_dirty_pmd(pmd_t pmd) |
1758 | { | |
1759 | #ifdef CONFIG_MEM_SOFT_DIRTY | |
1760 | if (unlikely(is_pmd_migration_entry(pmd))) | |
1761 | pmd = pmd_swp_mksoft_dirty(pmd); | |
1762 | else if (pmd_present(pmd)) | |
1763 | pmd = pmd_mksoft_dirty(pmd); | |
1764 | #endif | |
1765 | return pmd; | |
1766 | } | |
1767 | ||
bf8616d5 | 1768 | bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, |
b8aa9d9d | 1769 | unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) |
37a1c49a | 1770 | { |
bf929152 | 1771 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a | 1772 | pmd_t pmd; |
37a1c49a | 1773 | struct mm_struct *mm = vma->vm_mm; |
5d190420 | 1774 | bool force_flush = false; |
37a1c49a | 1775 | |
37a1c49a AA |
1776 | /* |
1777 | * The destination pmd shouldn't be established, free_pgtables() | |
1778 | * should have release it. | |
1779 | */ | |
1780 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1781 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
4b471e88 | 1782 | return false; |
37a1c49a AA |
1783 | } |
1784 | ||
bf929152 KS |
1785 | /* |
1786 | * We don't have to worry about the ordering of src and dst | |
c1e8d7c6 | 1787 | * ptlocks because exclusive mmap_lock prevents deadlock. |
bf929152 | 1788 | */ |
b6ec57f4 KS |
1789 | old_ptl = __pmd_trans_huge_lock(old_pmd, vma); |
1790 | if (old_ptl) { | |
bf929152 KS |
1791 | new_ptl = pmd_lockptr(mm, new_pmd); |
1792 | if (new_ptl != old_ptl) | |
1793 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
8809aa2d | 1794 | pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd); |
eb66ae03 | 1795 | if (pmd_present(pmd)) |
a2ce2666 | 1796 | force_flush = true; |
025c5b24 | 1797 | VM_BUG_ON(!pmd_none(*new_pmd)); |
3592806c | 1798 | |
1dd38b6c | 1799 | if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) { |
b3084f4d | 1800 | pgtable_t pgtable; |
3592806c KS |
1801 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1802 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1803 | } |
ab6e3d09 NH |
1804 | pmd = move_soft_dirty_pmd(pmd); |
1805 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
5d190420 | 1806 | if (force_flush) |
7c38f181 | 1807 | flush_pmd_tlb_range(vma, old_addr, old_addr + PMD_SIZE); |
eb66ae03 LT |
1808 | if (new_ptl != old_ptl) |
1809 | spin_unlock(new_ptl); | |
bf929152 | 1810 | spin_unlock(old_ptl); |
4b471e88 | 1811 | return true; |
37a1c49a | 1812 | } |
4b471e88 | 1813 | return false; |
37a1c49a AA |
1814 | } |
1815 | ||
f123d74a MG |
1816 | /* |
1817 | * Returns | |
1818 | * - 0 if PMD could not be locked | |
f0953a1b | 1819 | * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary |
e346e668 | 1820 | * or if prot_numa but THP migration is not supported |
f0953a1b | 1821 | * - HPAGE_PMD_NR if protections changed and TLB flush necessary |
f123d74a | 1822 | */ |
4a18419f NA |
1823 | int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
1824 | pmd_t *pmd, unsigned long addr, pgprot_t newprot, | |
1825 | unsigned long cp_flags) | |
cd7548ab JW |
1826 | { |
1827 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1828 | spinlock_t *ptl; |
c9fe6656 | 1829 | pmd_t oldpmd, entry; |
58705444 | 1830 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; |
292924b2 PX |
1831 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
1832 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
6a56ccbc | 1833 | int ret = 1; |
cd7548ab | 1834 | |
4a18419f NA |
1835 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); |
1836 | ||
e346e668 YS |
1837 | if (prot_numa && !thp_migration_supported()) |
1838 | return 1; | |
1839 | ||
b6ec57f4 | 1840 | ptl = __pmd_trans_huge_lock(pmd, vma); |
0a85e51d KS |
1841 | if (!ptl) |
1842 | return 0; | |
e944fd67 | 1843 | |
84c3fc4e ZY |
1844 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
1845 | if (is_swap_pmd(*pmd)) { | |
1846 | swp_entry_t entry = pmd_to_swp_entry(*pmd); | |
6c287605 | 1847 | struct page *page = pfn_swap_entry_to_page(entry); |
84c3fc4e ZY |
1848 | |
1849 | VM_BUG_ON(!is_pmd_migration_entry(*pmd)); | |
4dd845b5 | 1850 | if (is_writable_migration_entry(entry)) { |
84c3fc4e ZY |
1851 | pmd_t newpmd; |
1852 | /* | |
1853 | * A protection check is difficult so | |
1854 | * just be safe and disable write | |
1855 | */ | |
6c287605 DH |
1856 | if (PageAnon(page)) |
1857 | entry = make_readable_exclusive_migration_entry(swp_offset(entry)); | |
1858 | else | |
1859 | entry = make_readable_migration_entry(swp_offset(entry)); | |
84c3fc4e | 1860 | newpmd = swp_entry_to_pmd(entry); |
ab6e3d09 NH |
1861 | if (pmd_swp_soft_dirty(*pmd)) |
1862 | newpmd = pmd_swp_mksoft_dirty(newpmd); | |
8f34f1ea PX |
1863 | if (pmd_swp_uffd_wp(*pmd)) |
1864 | newpmd = pmd_swp_mkuffd_wp(newpmd); | |
84c3fc4e ZY |
1865 | set_pmd_at(mm, addr, pmd, newpmd); |
1866 | } | |
1867 | goto unlock; | |
1868 | } | |
1869 | #endif | |
1870 | ||
a1a3a2fc HY |
1871 | if (prot_numa) { |
1872 | struct page *page; | |
33024536 | 1873 | bool toptier; |
a1a3a2fc HY |
1874 | /* |
1875 | * Avoid trapping faults against the zero page. The read-only | |
1876 | * data is likely to be read-cached on the local CPU and | |
1877 | * local/remote hits to the zero page are not interesting. | |
1878 | */ | |
1879 | if (is_huge_zero_pmd(*pmd)) | |
1880 | goto unlock; | |
025c5b24 | 1881 | |
a1a3a2fc HY |
1882 | if (pmd_protnone(*pmd)) |
1883 | goto unlock; | |
0a85e51d | 1884 | |
a1a3a2fc | 1885 | page = pmd_page(*pmd); |
33024536 | 1886 | toptier = node_is_toptier(page_to_nid(page)); |
a1a3a2fc HY |
1887 | /* |
1888 | * Skip scanning top tier node if normal numa | |
1889 | * balancing is disabled | |
1890 | */ | |
1891 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && | |
33024536 | 1892 | toptier) |
a1a3a2fc | 1893 | goto unlock; |
33024536 HY |
1894 | |
1895 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && | |
1896 | !toptier) | |
1897 | xchg_page_access_time(page, jiffies_to_msecs(jiffies)); | |
a1a3a2fc | 1898 | } |
ced10803 | 1899 | /* |
3e4e28c5 | 1900 | * In case prot_numa, we are under mmap_read_lock(mm). It's critical |
ced10803 | 1901 | * to not clear pmd intermittently to avoid race with MADV_DONTNEED |
3e4e28c5 | 1902 | * which is also under mmap_read_lock(mm): |
ced10803 KS |
1903 | * |
1904 | * CPU0: CPU1: | |
1905 | * change_huge_pmd(prot_numa=1) | |
1906 | * pmdp_huge_get_and_clear_notify() | |
1907 | * madvise_dontneed() | |
1908 | * zap_pmd_range() | |
1909 | * pmd_trans_huge(*pmd) == 0 (without ptl) | |
1910 | * // skip the pmd | |
1911 | * set_pmd_at(); | |
1912 | * // pmd is re-established | |
1913 | * | |
1914 | * The race makes MADV_DONTNEED miss the huge pmd and don't clear it | |
1915 | * which may break userspace. | |
1916 | * | |
4f831457 | 1917 | * pmdp_invalidate_ad() is required to make sure we don't miss |
ced10803 KS |
1918 | * dirty/young flags set by hardware. |
1919 | */ | |
4f831457 | 1920 | oldpmd = pmdp_invalidate_ad(vma, addr, pmd); |
ced10803 | 1921 | |
c9fe6656 | 1922 | entry = pmd_modify(oldpmd, newprot); |
292924b2 PX |
1923 | if (uffd_wp) { |
1924 | entry = pmd_wrprotect(entry); | |
1925 | entry = pmd_mkuffd_wp(entry); | |
1926 | } else if (uffd_wp_resolve) { | |
1927 | /* | |
1928 | * Leave the write bit to be handled by PF interrupt | |
1929 | * handler, then things like COW could be properly | |
1930 | * handled. | |
1931 | */ | |
1932 | entry = pmd_clear_uffd_wp(entry); | |
1933 | } | |
c27f479e DH |
1934 | |
1935 | /* See change_pte_range(). */ | |
1936 | if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) && | |
1937 | can_change_pmd_writable(vma, addr, entry)) | |
1938 | entry = pmd_mkwrite(entry); | |
1939 | ||
0a85e51d KS |
1940 | ret = HPAGE_PMD_NR; |
1941 | set_pmd_at(mm, addr, pmd, entry); | |
4a18419f | 1942 | |
c9fe6656 NA |
1943 | if (huge_pmd_needs_flush(oldpmd, entry)) |
1944 | tlb_flush_pmd_range(tlb, addr, HPAGE_PMD_SIZE); | |
0a85e51d KS |
1945 | unlock: |
1946 | spin_unlock(ptl); | |
025c5b24 NH |
1947 | return ret; |
1948 | } | |
1949 | ||
1950 | /* | |
8f19b0c0 | 1951 | * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise. |
025c5b24 | 1952 | * |
8f19b0c0 HY |
1953 | * Note that if it returns page table lock pointer, this routine returns without |
1954 | * unlocking page table lock. So callers must unlock it. | |
025c5b24 | 1955 | */ |
b6ec57f4 | 1956 | spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) |
025c5b24 | 1957 | { |
b6ec57f4 KS |
1958 | spinlock_t *ptl; |
1959 | ptl = pmd_lock(vma->vm_mm, pmd); | |
84c3fc4e ZY |
1960 | if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || |
1961 | pmd_devmap(*pmd))) | |
b6ec57f4 KS |
1962 | return ptl; |
1963 | spin_unlock(ptl); | |
1964 | return NULL; | |
cd7548ab JW |
1965 | } |
1966 | ||
a00cc7d9 | 1967 | /* |
d965e390 | 1968 | * Returns page table lock pointer if a given pud maps a thp, NULL otherwise. |
a00cc7d9 | 1969 | * |
d965e390 ML |
1970 | * Note that if it returns page table lock pointer, this routine returns without |
1971 | * unlocking page table lock. So callers must unlock it. | |
a00cc7d9 MW |
1972 | */ |
1973 | spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) | |
1974 | { | |
1975 | spinlock_t *ptl; | |
1976 | ||
1977 | ptl = pud_lock(vma->vm_mm, pud); | |
1978 | if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) | |
1979 | return ptl; | |
1980 | spin_unlock(ptl); | |
1981 | return NULL; | |
1982 | } | |
1983 | ||
1984 | #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD | |
1985 | int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
1986 | pud_t *pud, unsigned long addr) | |
1987 | { | |
a00cc7d9 MW |
1988 | spinlock_t *ptl; |
1989 | ||
1990 | ptl = __pud_trans_huge_lock(pud, vma); | |
1991 | if (!ptl) | |
1992 | return 0; | |
74929079 | 1993 | |
70516b93 | 1994 | pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); |
a00cc7d9 | 1995 | tlb_remove_pud_tlb_entry(tlb, pud, addr); |
2484ca9b | 1996 | if (vma_is_special_huge(vma)) { |
a00cc7d9 MW |
1997 | spin_unlock(ptl); |
1998 | /* No zero page support yet */ | |
1999 | } else { | |
2000 | /* No support for anonymous PUD pages yet */ | |
2001 | BUG(); | |
2002 | } | |
2003 | return 1; | |
2004 | } | |
2005 | ||
2006 | static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, | |
2007 | unsigned long haddr) | |
2008 | { | |
2009 | VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); | |
2010 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2011 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); | |
2012 | VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); | |
2013 | ||
ce9311cf | 2014 | count_vm_event(THP_SPLIT_PUD); |
a00cc7d9 MW |
2015 | |
2016 | pudp_huge_clear_flush_notify(vma, haddr, pud); | |
2017 | } | |
2018 | ||
2019 | void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, | |
2020 | unsigned long address) | |
2021 | { | |
2022 | spinlock_t *ptl; | |
ac46d4f3 | 2023 | struct mmu_notifier_range range; |
a00cc7d9 | 2024 | |
7269f999 | 2025 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2026 | address & HPAGE_PUD_MASK, |
ac46d4f3 JG |
2027 | (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE); |
2028 | mmu_notifier_invalidate_range_start(&range); | |
2029 | ptl = pud_lock(vma->vm_mm, pud); | |
a00cc7d9 MW |
2030 | if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud))) |
2031 | goto out; | |
ac46d4f3 | 2032 | __split_huge_pud_locked(vma, pud, range.start); |
a00cc7d9 MW |
2033 | |
2034 | out: | |
2035 | spin_unlock(ptl); | |
4645b9fe JG |
2036 | /* |
2037 | * No need to double call mmu_notifier->invalidate_range() callback as | |
2038 | * the above pudp_huge_clear_flush_notify() did already call it. | |
2039 | */ | |
ac46d4f3 | 2040 | mmu_notifier_invalidate_range_only_end(&range); |
a00cc7d9 MW |
2041 | } |
2042 | #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ | |
2043 | ||
eef1b3ba KS |
2044 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2045 | unsigned long haddr, pmd_t *pmd) | |
2046 | { | |
2047 | struct mm_struct *mm = vma->vm_mm; | |
2048 | pgtable_t pgtable; | |
2049 | pmd_t _pmd; | |
2050 | int i; | |
2051 | ||
0f10851e JG |
2052 | /* |
2053 | * Leave pmd empty until pte is filled note that it is fine to delay | |
2054 | * notification until mmu_notifier_invalidate_range_end() as we are | |
2055 | * replacing a zero pmd write protected page with a zero pte write | |
2056 | * protected page. | |
2057 | * | |
ee65728e | 2058 | * See Documentation/mm/mmu_notifier.rst |
0f10851e JG |
2059 | */ |
2060 | pmdp_huge_clear_flush(vma, haddr, pmd); | |
eef1b3ba KS |
2061 | |
2062 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); | |
2063 | pmd_populate(mm, &_pmd, pgtable); | |
2064 | ||
2065 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2066 | pte_t *pte, entry; | |
2067 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2068 | entry = pte_mkspecial(entry); | |
2069 | pte = pte_offset_map(&_pmd, haddr); | |
2070 | VM_BUG_ON(!pte_none(*pte)); | |
2071 | set_pte_at(mm, haddr, pte, entry); | |
2072 | pte_unmap(pte); | |
2073 | } | |
2074 | smp_wmb(); /* make pte visible before pmd */ | |
2075 | pmd_populate(mm, pmd, pgtable); | |
eef1b3ba KS |
2076 | } |
2077 | ||
2078 | static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, | |
ba988280 | 2079 | unsigned long haddr, bool freeze) |
eef1b3ba KS |
2080 | { |
2081 | struct mm_struct *mm = vma->vm_mm; | |
2082 | struct page *page; | |
2083 | pgtable_t pgtable; | |
423ac9af | 2084 | pmd_t old_pmd, _pmd; |
292924b2 | 2085 | bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; |
0ccf7f16 | 2086 | bool anon_exclusive = false, dirty = false; |
2ac015e2 | 2087 | unsigned long addr; |
eef1b3ba KS |
2088 | int i; |
2089 | ||
2090 | VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); | |
2091 | VM_BUG_ON_VMA(vma->vm_start > haddr, vma); | |
2092 | VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); | |
84c3fc4e ZY |
2093 | VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) |
2094 | && !pmd_devmap(*pmd)); | |
eef1b3ba KS |
2095 | |
2096 | count_vm_event(THP_SPLIT_PMD); | |
2097 | ||
d21b9e57 | 2098 | if (!vma_is_anonymous(vma)) { |
99fa8a48 | 2099 | old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); |
953c66c2 AK |
2100 | /* |
2101 | * We are going to unmap this huge page. So | |
2102 | * just go ahead and zap it | |
2103 | */ | |
2104 | if (arch_needs_pgtable_deposit()) | |
2105 | zap_deposited_table(mm, pmd); | |
2484ca9b | 2106 | if (vma_is_special_huge(vma)) |
d21b9e57 | 2107 | return; |
99fa8a48 HD |
2108 | if (unlikely(is_pmd_migration_entry(old_pmd))) { |
2109 | swp_entry_t entry; | |
2110 | ||
2111 | entry = pmd_to_swp_entry(old_pmd); | |
af5cdaf8 | 2112 | page = pfn_swap_entry_to_page(entry); |
99fa8a48 HD |
2113 | } else { |
2114 | page = pmd_page(old_pmd); | |
2115 | if (!PageDirty(page) && pmd_dirty(old_pmd)) | |
2116 | set_page_dirty(page); | |
2117 | if (!PageReferenced(page) && pmd_young(old_pmd)) | |
2118 | SetPageReferenced(page); | |
cea86fe2 | 2119 | page_remove_rmap(page, vma, true); |
99fa8a48 HD |
2120 | put_page(page); |
2121 | } | |
fadae295 | 2122 | add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); |
eef1b3ba | 2123 | return; |
99fa8a48 HD |
2124 | } |
2125 | ||
3b77e8c8 | 2126 | if (is_huge_zero_pmd(*pmd)) { |
4645b9fe JG |
2127 | /* |
2128 | * FIXME: Do we want to invalidate secondary mmu by calling | |
2129 | * mmu_notifier_invalidate_range() see comments below inside | |
2130 | * __split_huge_pmd() ? | |
2131 | * | |
2132 | * We are going from a zero huge page write protected to zero | |
2133 | * small page also write protected so it does not seems useful | |
2134 | * to invalidate secondary mmu at this time. | |
2135 | */ | |
eef1b3ba KS |
2136 | return __split_huge_zero_page_pmd(vma, haddr, pmd); |
2137 | } | |
2138 | ||
423ac9af AK |
2139 | /* |
2140 | * Up to this point the pmd is present and huge and userland has the | |
2141 | * whole access to the hugepage during the split (which happens in | |
2142 | * place). If we overwrite the pmd with the not-huge version pointing | |
2143 | * to the pte here (which of course we could if all CPUs were bug | |
2144 | * free), userland could trigger a small page size TLB miss on the | |
2145 | * small sized TLB while the hugepage TLB entry is still established in | |
2146 | * the huge TLB. Some CPU doesn't like that. | |
42742d9b AK |
2147 | * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum |
2148 | * 383 on page 105. Intel should be safe but is also warns that it's | |
423ac9af AK |
2149 | * only safe if the permission and cache attributes of the two entries |
2150 | * loaded in the two TLB is identical (which should be the case here). | |
2151 | * But it is generally safer to never allow small and huge TLB entries | |
2152 | * for the same virtual address to be loaded simultaneously. So instead | |
2153 | * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the | |
2154 | * current pmd notpresent (atomically because here the pmd_trans_huge | |
2155 | * must remain set at all times on the pmd until the split is complete | |
2156 | * for this pmd), then we flush the SMP TLB and finally we write the | |
2157 | * non-huge version of the pmd entry with pmd_populate. | |
2158 | */ | |
2159 | old_pmd = pmdp_invalidate(vma, haddr, pmd); | |
2160 | ||
423ac9af | 2161 | pmd_migration = is_pmd_migration_entry(old_pmd); |
2e83ee1d | 2162 | if (unlikely(pmd_migration)) { |
84c3fc4e ZY |
2163 | swp_entry_t entry; |
2164 | ||
423ac9af | 2165 | entry = pmd_to_swp_entry(old_pmd); |
af5cdaf8 | 2166 | page = pfn_swap_entry_to_page(entry); |
4dd845b5 | 2167 | write = is_writable_migration_entry(entry); |
6c287605 DH |
2168 | if (PageAnon(page)) |
2169 | anon_exclusive = is_readable_exclusive_migration_entry(entry); | |
2e346877 PX |
2170 | young = is_migration_entry_young(entry); |
2171 | dirty = is_migration_entry_dirty(entry); | |
2e83ee1d | 2172 | soft_dirty = pmd_swp_soft_dirty(old_pmd); |
f45ec5ff | 2173 | uffd_wp = pmd_swp_uffd_wp(old_pmd); |
2e83ee1d | 2174 | } else { |
423ac9af | 2175 | page = pmd_page(old_pmd); |
0ccf7f16 PX |
2176 | if (pmd_dirty(old_pmd)) { |
2177 | dirty = true; | |
2e83ee1d | 2178 | SetPageDirty(page); |
0ccf7f16 | 2179 | } |
2e83ee1d PX |
2180 | write = pmd_write(old_pmd); |
2181 | young = pmd_young(old_pmd); | |
2182 | soft_dirty = pmd_soft_dirty(old_pmd); | |
292924b2 | 2183 | uffd_wp = pmd_uffd_wp(old_pmd); |
6c287605 | 2184 | |
9d84604b | 2185 | VM_BUG_ON_PAGE(!page_count(page), page); |
6c287605 DH |
2186 | |
2187 | /* | |
2188 | * Without "freeze", we'll simply split the PMD, propagating the | |
2189 | * PageAnonExclusive() flag for each PTE by setting it for | |
2190 | * each subpage -- no need to (temporarily) clear. | |
2191 | * | |
2192 | * With "freeze" we want to replace mapped pages by | |
2193 | * migration entries right away. This is only possible if we | |
2194 | * managed to clear PageAnonExclusive() -- see | |
2195 | * set_pmd_migration_entry(). | |
2196 | * | |
2197 | * In case we cannot clear PageAnonExclusive(), split the PMD | |
2198 | * only and let try_to_migrate_one() fail later. | |
088b8aa5 DH |
2199 | * |
2200 | * See page_try_share_anon_rmap(): invalidate PMD first. | |
6c287605 DH |
2201 | */ |
2202 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); | |
2203 | if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) | |
2204 | freeze = false; | |
96d82deb HD |
2205 | if (!freeze) |
2206 | page_ref_add(page, HPAGE_PMD_NR - 1); | |
2e83ee1d | 2207 | } |
eef1b3ba | 2208 | |
423ac9af AK |
2209 | /* |
2210 | * Withdraw the table only after we mark the pmd entry invalid. | |
2211 | * This's critical for some architectures (Power). | |
2212 | */ | |
eef1b3ba KS |
2213 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
2214 | pmd_populate(mm, &_pmd, pgtable); | |
2215 | ||
2ac015e2 | 2216 | for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { |
eef1b3ba KS |
2217 | pte_t entry, *pte; |
2218 | /* | |
2219 | * Note that NUMA hinting access restrictions are not | |
2220 | * transferred to avoid any possibility of altering | |
2221 | * permissions across VMAs. | |
2222 | */ | |
84c3fc4e | 2223 | if (freeze || pmd_migration) { |
ba988280 | 2224 | swp_entry_t swp_entry; |
4dd845b5 AP |
2225 | if (write) |
2226 | swp_entry = make_writable_migration_entry( | |
2227 | page_to_pfn(page + i)); | |
6c287605 DH |
2228 | else if (anon_exclusive) |
2229 | swp_entry = make_readable_exclusive_migration_entry( | |
2230 | page_to_pfn(page + i)); | |
4dd845b5 AP |
2231 | else |
2232 | swp_entry = make_readable_migration_entry( | |
2233 | page_to_pfn(page + i)); | |
2e346877 PX |
2234 | if (young) |
2235 | swp_entry = make_migration_entry_young(swp_entry); | |
2236 | if (dirty) | |
2237 | swp_entry = make_migration_entry_dirty(swp_entry); | |
ba988280 | 2238 | entry = swp_entry_to_pte(swp_entry); |
804dd150 AA |
2239 | if (soft_dirty) |
2240 | entry = pte_swp_mksoft_dirty(entry); | |
f45ec5ff PX |
2241 | if (uffd_wp) |
2242 | entry = pte_swp_mkuffd_wp(entry); | |
ba988280 | 2243 | } else { |
6d2329f8 | 2244 | entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); |
b8d3c4c3 | 2245 | entry = maybe_mkwrite(entry, vma); |
6c287605 DH |
2246 | if (anon_exclusive) |
2247 | SetPageAnonExclusive(page + i); | |
ba988280 KS |
2248 | if (!young) |
2249 | entry = pte_mkold(entry); | |
e833bc50 PX |
2250 | /* NOTE: this may set soft-dirty too on some archs */ |
2251 | if (dirty) | |
2252 | entry = pte_mkdirty(entry); | |
624a2c94 | 2253 | /* |
e833bc50 PX |
2254 | * NOTE: this needs to happen after pte_mkdirty, |
2255 | * because some archs (sparc64, loongarch) could | |
2256 | * set hw write bit when mkdirty. | |
624a2c94 | 2257 | */ |
e833bc50 PX |
2258 | if (!write) |
2259 | entry = pte_wrprotect(entry); | |
804dd150 AA |
2260 | if (soft_dirty) |
2261 | entry = pte_mksoft_dirty(entry); | |
292924b2 PX |
2262 | if (uffd_wp) |
2263 | entry = pte_mkuffd_wp(entry); | |
96d82deb | 2264 | page_add_anon_rmap(page + i, vma, addr, false); |
ba988280 | 2265 | } |
2ac015e2 | 2266 | pte = pte_offset_map(&_pmd, addr); |
eef1b3ba | 2267 | BUG_ON(!pte_none(*pte)); |
2ac015e2 | 2268 | set_pte_at(mm, addr, pte, entry); |
ec0abae6 | 2269 | pte_unmap(pte); |
eef1b3ba KS |
2270 | } |
2271 | ||
cb67f428 HD |
2272 | if (!pmd_migration) |
2273 | page_remove_rmap(page, vma, true); | |
96d82deb HD |
2274 | if (freeze) |
2275 | put_page(page); | |
eef1b3ba KS |
2276 | |
2277 | smp_wmb(); /* make pte visible before pmd */ | |
2278 | pmd_populate(mm, pmd, pgtable); | |
2279 | } | |
2280 | ||
2281 | void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, | |
af28a988 | 2282 | unsigned long address, bool freeze, struct folio *folio) |
eef1b3ba KS |
2283 | { |
2284 | spinlock_t *ptl; | |
ac46d4f3 | 2285 | struct mmu_notifier_range range; |
eef1b3ba | 2286 | |
7269f999 | 2287 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
6f4f13e8 | 2288 | address & HPAGE_PMD_MASK, |
ac46d4f3 JG |
2289 | (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); |
2290 | mmu_notifier_invalidate_range_start(&range); | |
2291 | ptl = pmd_lock(vma->vm_mm, pmd); | |
33f4751e NH |
2292 | |
2293 | /* | |
af28a988 MWO |
2294 | * If caller asks to setup a migration entry, we need a folio to check |
2295 | * pmd against. Otherwise we can end up replacing wrong folio. | |
33f4751e | 2296 | */ |
af28a988 | 2297 | VM_BUG_ON(freeze && !folio); |
83a8441f | 2298 | VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); |
33f4751e | 2299 | |
7f760917 | 2300 | if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || |
83a8441f | 2301 | is_pmd_migration_entry(*pmd)) { |
cea33328 ML |
2302 | /* |
2303 | * It's safe to call pmd_page when folio is set because it's | |
2304 | * guaranteed that pmd is present. | |
2305 | */ | |
83a8441f MWO |
2306 | if (folio && folio != page_folio(pmd_page(*pmd))) |
2307 | goto out; | |
7f760917 | 2308 | __split_huge_pmd_locked(vma, pmd, range.start, freeze); |
83a8441f | 2309 | } |
7f760917 | 2310 | |
e90309c9 | 2311 | out: |
eef1b3ba | 2312 | spin_unlock(ptl); |
4645b9fe JG |
2313 | /* |
2314 | * No need to double call mmu_notifier->invalidate_range() callback. | |
2315 | * They are 3 cases to consider inside __split_huge_pmd_locked(): | |
2316 | * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious | |
2317 | * 2) __split_huge_zero_page_pmd() read only zero page and any write | |
2318 | * fault will trigger a flush_notify before pointing to a new page | |
2319 | * (it is fine if the secondary mmu keeps pointing to the old zero | |
2320 | * page in the meantime) | |
2321 | * 3) Split a huge pmd into pte pointing to the same page. No need | |
2322 | * to invalidate secondary tlb entry they are all still valid. | |
2323 | * any further changes to individual pte will notify. So no need | |
2324 | * to call mmu_notifier->invalidate_range() | |
2325 | */ | |
ac46d4f3 | 2326 | mmu_notifier_invalidate_range_only_end(&range); |
eef1b3ba KS |
2327 | } |
2328 | ||
fec89c10 | 2329 | void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, |
af28a988 | 2330 | bool freeze, struct folio *folio) |
94fcc585 | 2331 | { |
50722804 | 2332 | pmd_t *pmd = mm_find_pmd(vma->vm_mm, address); |
94fcc585 | 2333 | |
50722804 | 2334 | if (!pmd) |
f72e7dcd HD |
2335 | return; |
2336 | ||
af28a988 | 2337 | __split_huge_pmd(vma, pmd, address, freeze, folio); |
94fcc585 AA |
2338 | } |
2339 | ||
71f9e58e ML |
2340 | static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address) |
2341 | { | |
2342 | /* | |
2343 | * If the new address isn't hpage aligned and it could previously | |
2344 | * contain an hugepage: check if we need to split an huge pmd. | |
2345 | */ | |
2346 | if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) && | |
2347 | range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE), | |
2348 | ALIGN(address, HPAGE_PMD_SIZE))) | |
2349 | split_huge_pmd_address(vma, address, false, NULL); | |
2350 | } | |
2351 | ||
e1b9996b | 2352 | void vma_adjust_trans_huge(struct vm_area_struct *vma, |
94fcc585 AA |
2353 | unsigned long start, |
2354 | unsigned long end, | |
2355 | long adjust_next) | |
2356 | { | |
71f9e58e ML |
2357 | /* Check if we need to split start first. */ |
2358 | split_huge_pmd_if_needed(vma, start); | |
94fcc585 | 2359 | |
71f9e58e ML |
2360 | /* Check if we need to split end next. */ |
2361 | split_huge_pmd_if_needed(vma, end); | |
94fcc585 AA |
2362 | |
2363 | /* | |
68540502 | 2364 | * If we're also updating the next vma vm_start, |
71f9e58e | 2365 | * check if we need to split it. |
94fcc585 AA |
2366 | */ |
2367 | if (adjust_next > 0) { | |
68540502 | 2368 | struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); |
94fcc585 | 2369 | unsigned long nstart = next->vm_start; |
f9d86a60 | 2370 | nstart += adjust_next; |
71f9e58e | 2371 | split_huge_pmd_if_needed(next, nstart); |
94fcc585 AA |
2372 | } |
2373 | } | |
e9b61f19 | 2374 | |
684555aa | 2375 | static void unmap_folio(struct folio *folio) |
e9b61f19 | 2376 | { |
a98a2f0c AP |
2377 | enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | |
2378 | TTU_SYNC; | |
e9b61f19 | 2379 | |
684555aa | 2380 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); |
e9b61f19 | 2381 | |
a98a2f0c AP |
2382 | /* |
2383 | * Anon pages need migration entries to preserve them, but file | |
2384 | * pages can simply be left unmapped, then faulted back on demand. | |
2385 | * If that is ever changed (perhaps for mlock), update remap_page(). | |
2386 | */ | |
4b8554c5 MWO |
2387 | if (folio_test_anon(folio)) |
2388 | try_to_migrate(folio, ttu_flags); | |
a98a2f0c | 2389 | else |
869f7ee6 | 2390 | try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); |
e9b61f19 KS |
2391 | } |
2392 | ||
4eecb8b9 | 2393 | static void remap_page(struct folio *folio, unsigned long nr) |
e9b61f19 | 2394 | { |
4eecb8b9 | 2395 | int i = 0; |
ab02c252 | 2396 | |
684555aa | 2397 | /* If unmap_folio() uses try_to_migrate() on file, remove this check */ |
4eecb8b9 | 2398 | if (!folio_test_anon(folio)) |
ab02c252 | 2399 | return; |
4eecb8b9 MWO |
2400 | for (;;) { |
2401 | remove_migration_ptes(folio, folio, true); | |
2402 | i += folio_nr_pages(folio); | |
2403 | if (i >= nr) | |
2404 | break; | |
2405 | folio = folio_next(folio); | |
ace71a19 | 2406 | } |
e9b61f19 KS |
2407 | } |
2408 | ||
94866635 | 2409 | static void lru_add_page_tail(struct page *head, struct page *tail, |
88dcb9a3 AS |
2410 | struct lruvec *lruvec, struct list_head *list) |
2411 | { | |
94866635 AS |
2412 | VM_BUG_ON_PAGE(!PageHead(head), head); |
2413 | VM_BUG_ON_PAGE(PageCompound(tail), head); | |
2414 | VM_BUG_ON_PAGE(PageLRU(tail), head); | |
6168d0da | 2415 | lockdep_assert_held(&lruvec->lru_lock); |
88dcb9a3 | 2416 | |
6dbb5741 | 2417 | if (list) { |
88dcb9a3 | 2418 | /* page reclaim is reclaiming a huge page */ |
6dbb5741 | 2419 | VM_WARN_ON(PageLRU(head)); |
94866635 AS |
2420 | get_page(tail); |
2421 | list_add_tail(&tail->lru, list); | |
88dcb9a3 | 2422 | } else { |
6dbb5741 AS |
2423 | /* head is still on lru (and we have it frozen) */ |
2424 | VM_WARN_ON(!PageLRU(head)); | |
07ca7606 HD |
2425 | if (PageUnevictable(tail)) |
2426 | tail->mlock_count = 0; | |
2427 | else | |
2428 | list_add_tail(&tail->lru, &head->lru); | |
6dbb5741 | 2429 | SetPageLRU(tail); |
88dcb9a3 AS |
2430 | } |
2431 | } | |
2432 | ||
8df651c7 | 2433 | static void __split_huge_page_tail(struct page *head, int tail, |
e9b61f19 KS |
2434 | struct lruvec *lruvec, struct list_head *list) |
2435 | { | |
e9b61f19 KS |
2436 | struct page *page_tail = head + tail; |
2437 | ||
8df651c7 | 2438 | VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); |
e9b61f19 KS |
2439 | |
2440 | /* | |
605ca5ed KK |
2441 | * Clone page flags before unfreezing refcount. |
2442 | * | |
2443 | * After successful get_page_unless_zero() might follow flags change, | |
8958b249 | 2444 | * for example lock_page() which set PG_waiters. |
6c287605 DH |
2445 | * |
2446 | * Note that for mapped sub-pages of an anonymous THP, | |
684555aa | 2447 | * PG_anon_exclusive has been cleared in unmap_folio() and is stored in |
6c287605 DH |
2448 | * the migration entry instead from where remap_page() will restore it. |
2449 | * We can still have PG_anon_exclusive set on effectively unmapped and | |
2450 | * unreferenced sub-pages of an anonymous THP: we can simply drop | |
2451 | * PG_anon_exclusive (-> PG_mappedtodisk) for these here. | |
e9b61f19 | 2452 | */ |
e9b61f19 KS |
2453 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
2454 | page_tail->flags |= (head->flags & | |
2455 | ((1L << PG_referenced) | | |
2456 | (1L << PG_swapbacked) | | |
38d8b4e6 | 2457 | (1L << PG_swapcache) | |
e9b61f19 KS |
2458 | (1L << PG_mlocked) | |
2459 | (1L << PG_uptodate) | | |
2460 | (1L << PG_active) | | |
1899ad18 | 2461 | (1L << PG_workingset) | |
e9b61f19 | 2462 | (1L << PG_locked) | |
b8d3c4c3 | 2463 | (1L << PG_unevictable) | |
b0284cd2 | 2464 | #ifdef CONFIG_ARCH_USES_PG_ARCH_X |
72e6afa0 | 2465 | (1L << PG_arch_2) | |
ef6458b1 | 2466 | (1L << PG_arch_3) | |
72e6afa0 | 2467 | #endif |
ec1c86b2 YZ |
2468 | (1L << PG_dirty) | |
2469 | LRU_GEN_MASK | LRU_REFS_MASK)); | |
e9b61f19 | 2470 | |
cb67f428 | 2471 | /* ->mapping in first and second tail page is replaced by other uses */ |
173d9d9f HD |
2472 | VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, |
2473 | page_tail); | |
2474 | page_tail->mapping = head->mapping; | |
2475 | page_tail->index = head->index + tail; | |
71e2d666 MG |
2476 | |
2477 | /* | |
2478 | * page->private should not be set in tail pages with the exception | |
2479 | * of swap cache pages that store the swp_entry_t in tail pages. | |
2480 | * Fix up and warn once if private is unexpectedly set. | |
cb67f428 HD |
2481 | * |
2482 | * What of 32-bit systems, on which head[1].compound_pincount overlays | |
2483 | * head[1].private? No problem: THP_SWAP is not enabled on 32-bit, and | |
2484 | * compound_pincount must be 0 for folio_ref_freeze() to have succeeded. | |
71e2d666 MG |
2485 | */ |
2486 | if (!folio_test_swapcache(page_folio(head))) { | |
5aae9265 | 2487 | VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, page_tail); |
71e2d666 MG |
2488 | page_tail->private = 0; |
2489 | } | |
173d9d9f | 2490 | |
605ca5ed | 2491 | /* Page flags must be visible before we make the page non-compound. */ |
e9b61f19 KS |
2492 | smp_wmb(); |
2493 | ||
605ca5ed KK |
2494 | /* |
2495 | * Clear PageTail before unfreezing page refcount. | |
2496 | * | |
2497 | * After successful get_page_unless_zero() might follow put_page() | |
2498 | * which needs correct compound_head(). | |
2499 | */ | |
e9b61f19 KS |
2500 | clear_compound_head(page_tail); |
2501 | ||
605ca5ed KK |
2502 | /* Finally unfreeze refcount. Additional reference from page cache. */ |
2503 | page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) || | |
2504 | PageSwapCache(head))); | |
2505 | ||
e9b61f19 KS |
2506 | if (page_is_young(head)) |
2507 | set_page_young(page_tail); | |
2508 | if (page_is_idle(head)) | |
2509 | set_page_idle(page_tail); | |
2510 | ||
e9b61f19 | 2511 | page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); |
94723aaf MH |
2512 | |
2513 | /* | |
2514 | * always add to the tail because some iterators expect new | |
2515 | * pages to show after the currently processed elements - e.g. | |
2516 | * migrate_pages | |
2517 | */ | |
e9b61f19 | 2518 | lru_add_page_tail(head, page_tail, lruvec, list); |
e9b61f19 KS |
2519 | } |
2520 | ||
baa355fd | 2521 | static void __split_huge_page(struct page *page, struct list_head *list, |
b6769834 | 2522 | pgoff_t end) |
e9b61f19 | 2523 | { |
e809c3fe MWO |
2524 | struct folio *folio = page_folio(page); |
2525 | struct page *head = &folio->page; | |
e9b61f19 | 2526 | struct lruvec *lruvec; |
4101196b MWO |
2527 | struct address_space *swap_cache = NULL; |
2528 | unsigned long offset = 0; | |
8cce5475 | 2529 | unsigned int nr = thp_nr_pages(head); |
8df651c7 | 2530 | int i; |
e9b61f19 | 2531 | |
e9b61f19 | 2532 | /* complete memcg works before add pages to LRU */ |
be6c8982 | 2533 | split_page_memcg(head, nr); |
e9b61f19 | 2534 | |
4101196b MWO |
2535 | if (PageAnon(head) && PageSwapCache(head)) { |
2536 | swp_entry_t entry = { .val = page_private(head) }; | |
2537 | ||
2538 | offset = swp_offset(entry); | |
2539 | swap_cache = swap_address_space(entry); | |
2540 | xa_lock(&swap_cache->i_pages); | |
2541 | } | |
2542 | ||
f0953a1b | 2543 | /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ |
e809c3fe | 2544 | lruvec = folio_lruvec_lock(folio); |
b6769834 | 2545 | |
eac96c3e YS |
2546 | ClearPageHasHWPoisoned(head); |
2547 | ||
8cce5475 | 2548 | for (i = nr - 1; i >= 1; i--) { |
8df651c7 | 2549 | __split_huge_page_tail(head, i, lruvec, list); |
d144bf62 | 2550 | /* Some pages can be beyond EOF: drop them from page cache */ |
baa355fd | 2551 | if (head[i].index >= end) { |
fb5c2029 MWO |
2552 | struct folio *tail = page_folio(head + i); |
2553 | ||
d144bf62 | 2554 | if (shmem_mapping(head->mapping)) |
800d8c63 | 2555 | shmem_uncharge(head->mapping->host, 1); |
fb5c2029 MWO |
2556 | else if (folio_test_clear_dirty(tail)) |
2557 | folio_account_cleaned(tail, | |
2558 | inode_to_wb(folio->mapping->host)); | |
2559 | __filemap_remove_folio(tail, NULL); | |
2560 | folio_put(tail); | |
4101196b MWO |
2561 | } else if (!PageAnon(page)) { |
2562 | __xa_store(&head->mapping->i_pages, head[i].index, | |
2563 | head + i, 0); | |
2564 | } else if (swap_cache) { | |
2565 | __xa_store(&swap_cache->i_pages, offset + i, | |
2566 | head + i, 0); | |
baa355fd KS |
2567 | } |
2568 | } | |
e9b61f19 KS |
2569 | |
2570 | ClearPageCompound(head); | |
6168d0da | 2571 | unlock_page_lruvec(lruvec); |
b6769834 | 2572 | /* Caller disabled irqs, so they are still disabled here */ |
f7da677b | 2573 | |
8cce5475 | 2574 | split_page_owner(head, nr); |
f7da677b | 2575 | |
baa355fd KS |
2576 | /* See comment in __split_huge_page_tail() */ |
2577 | if (PageAnon(head)) { | |
aa5dc07f | 2578 | /* Additional pin to swap cache */ |
4101196b | 2579 | if (PageSwapCache(head)) { |
38d8b4e6 | 2580 | page_ref_add(head, 2); |
4101196b MWO |
2581 | xa_unlock(&swap_cache->i_pages); |
2582 | } else { | |
38d8b4e6 | 2583 | page_ref_inc(head); |
4101196b | 2584 | } |
baa355fd | 2585 | } else { |
aa5dc07f | 2586 | /* Additional pin to page cache */ |
baa355fd | 2587 | page_ref_add(head, 2); |
b93b0163 | 2588 | xa_unlock(&head->mapping->i_pages); |
baa355fd | 2589 | } |
b6769834 | 2590 | local_irq_enable(); |
e9b61f19 | 2591 | |
4eecb8b9 | 2592 | remap_page(folio, nr); |
e9b61f19 | 2593 | |
c4f9c701 HY |
2594 | if (PageSwapCache(head)) { |
2595 | swp_entry_t entry = { .val = page_private(head) }; | |
2596 | ||
2597 | split_swap_cluster(entry); | |
2598 | } | |
2599 | ||
8cce5475 | 2600 | for (i = 0; i < nr; i++) { |
e9b61f19 KS |
2601 | struct page *subpage = head + i; |
2602 | if (subpage == page) | |
2603 | continue; | |
2604 | unlock_page(subpage); | |
2605 | ||
2606 | /* | |
2607 | * Subpages may be freed if there wasn't any mapping | |
2608 | * like if add_to_swap() is running on a lru page that | |
2609 | * had its mapping zapped. And freeing these pages | |
2610 | * requires taking the lru_lock so we do the put_page | |
2611 | * of the tail pages after the split is complete. | |
2612 | */ | |
0b175468 | 2613 | free_page_and_swap_cache(subpage); |
e9b61f19 KS |
2614 | } |
2615 | } | |
2616 | ||
b8f593cd | 2617 | /* Racy check whether the huge page can be split */ |
d4b4084a | 2618 | bool can_split_folio(struct folio *folio, int *pextra_pins) |
b8f593cd HY |
2619 | { |
2620 | int extra_pins; | |
2621 | ||
aa5dc07f | 2622 | /* Additional pins from page cache */ |
d4b4084a MWO |
2623 | if (folio_test_anon(folio)) |
2624 | extra_pins = folio_test_swapcache(folio) ? | |
2625 | folio_nr_pages(folio) : 0; | |
b8f593cd | 2626 | else |
d4b4084a | 2627 | extra_pins = folio_nr_pages(folio); |
b8f593cd HY |
2628 | if (pextra_pins) |
2629 | *pextra_pins = extra_pins; | |
d4b4084a | 2630 | return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1; |
b8f593cd HY |
2631 | } |
2632 | ||
e9b61f19 KS |
2633 | /* |
2634 | * This function splits huge page into normal pages. @page can point to any | |
2635 | * subpage of huge page to split. Split doesn't change the position of @page. | |
2636 | * | |
2637 | * Only caller must hold pin on the @page, otherwise split fails with -EBUSY. | |
2638 | * The huge page must be locked. | |
2639 | * | |
2640 | * If @list is null, tail pages will be added to LRU list, otherwise, to @list. | |
2641 | * | |
2642 | * Both head page and tail pages will inherit mapping, flags, and so on from | |
2643 | * the hugepage. | |
2644 | * | |
2645 | * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if | |
2646 | * they are not mapped. | |
2647 | * | |
2648 | * Returns 0 if the hugepage is split successfully. | |
2649 | * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under | |
2650 | * us. | |
2651 | */ | |
2652 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
2653 | { | |
4eecb8b9 | 2654 | struct folio *folio = page_folio(page); |
3e9a13da MWO |
2655 | struct deferred_split *ds_queue = get_deferred_split_queue(&folio->page); |
2656 | XA_STATE(xas, &folio->mapping->i_pages, folio->index); | |
baa355fd KS |
2657 | struct anon_vma *anon_vma = NULL; |
2658 | struct address_space *mapping = NULL; | |
504e070d | 2659 | int extra_pins, ret; |
006d3ff2 | 2660 | pgoff_t end; |
478d134e | 2661 | bool is_hzp; |
e9b61f19 | 2662 | |
3e9a13da MWO |
2663 | VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); |
2664 | VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); | |
e9b61f19 | 2665 | |
3e9a13da MWO |
2666 | is_hzp = is_huge_zero_page(&folio->page); |
2667 | VM_WARN_ON_ONCE_FOLIO(is_hzp, folio); | |
478d134e XY |
2668 | if (is_hzp) |
2669 | return -EBUSY; | |
2670 | ||
3e9a13da | 2671 | if (folio_test_writeback(folio)) |
59807685 HY |
2672 | return -EBUSY; |
2673 | ||
3e9a13da | 2674 | if (folio_test_anon(folio)) { |
baa355fd | 2675 | /* |
c1e8d7c6 | 2676 | * The caller does not necessarily hold an mmap_lock that would |
baa355fd KS |
2677 | * prevent the anon_vma disappearing so we first we take a |
2678 | * reference to it and then lock the anon_vma for write. This | |
2f031c6f | 2679 | * is similar to folio_lock_anon_vma_read except the write lock |
baa355fd KS |
2680 | * is taken to serialise against parallel split or collapse |
2681 | * operations. | |
2682 | */ | |
29eea9b5 | 2683 | anon_vma = folio_get_anon_vma(folio); |
baa355fd KS |
2684 | if (!anon_vma) { |
2685 | ret = -EBUSY; | |
2686 | goto out; | |
2687 | } | |
006d3ff2 | 2688 | end = -1; |
baa355fd KS |
2689 | mapping = NULL; |
2690 | anon_vma_lock_write(anon_vma); | |
2691 | } else { | |
6a3edd29 YF |
2692 | gfp_t gfp; |
2693 | ||
3e9a13da | 2694 | mapping = folio->mapping; |
baa355fd KS |
2695 | |
2696 | /* Truncated ? */ | |
2697 | if (!mapping) { | |
2698 | ret = -EBUSY; | |
2699 | goto out; | |
2700 | } | |
2701 | ||
6a3edd29 YF |
2702 | gfp = current_gfp_context(mapping_gfp_mask(mapping) & |
2703 | GFP_RECLAIM_MASK); | |
2704 | ||
2705 | if (folio_test_private(folio) && | |
2706 | !filemap_release_folio(folio, gfp)) { | |
2707 | ret = -EBUSY; | |
2708 | goto out; | |
2709 | } | |
2710 | ||
3e9a13da | 2711 | xas_split_alloc(&xas, folio, folio_order(folio), gfp); |
6b24ca4a MWO |
2712 | if (xas_error(&xas)) { |
2713 | ret = xas_error(&xas); | |
2714 | goto out; | |
2715 | } | |
2716 | ||
baa355fd KS |
2717 | anon_vma = NULL; |
2718 | i_mmap_lock_read(mapping); | |
006d3ff2 HD |
2719 | |
2720 | /* | |
2721 | *__split_huge_page() may need to trim off pages beyond EOF: | |
2722 | * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, | |
2723 | * which cannot be nested inside the page tree lock. So note | |
2724 | * end now: i_size itself may be changed at any moment, but | |
3e9a13da | 2725 | * folio lock is good enough to serialize the trimming. |
006d3ff2 HD |
2726 | */ |
2727 | end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); | |
d144bf62 HD |
2728 | if (shmem_mapping(mapping)) |
2729 | end = shmem_fallocend(mapping->host, end); | |
e9b61f19 | 2730 | } |
e9b61f19 KS |
2731 | |
2732 | /* | |
684555aa | 2733 | * Racy check if we can split the page, before unmap_folio() will |
e9b61f19 KS |
2734 | * split PMDs |
2735 | */ | |
d4b4084a | 2736 | if (!can_split_folio(folio, &extra_pins)) { |
fd4a7ac3 | 2737 | ret = -EAGAIN; |
e9b61f19 KS |
2738 | goto out_unlock; |
2739 | } | |
2740 | ||
684555aa | 2741 | unmap_folio(folio); |
e9b61f19 | 2742 | |
b6769834 AS |
2743 | /* block interrupt reentry in xa_lock and spinlock */ |
2744 | local_irq_disable(); | |
baa355fd | 2745 | if (mapping) { |
baa355fd | 2746 | /* |
3e9a13da MWO |
2747 | * Check if the folio is present in page cache. |
2748 | * We assume all tail are present too, if folio is there. | |
baa355fd | 2749 | */ |
6b24ca4a MWO |
2750 | xas_lock(&xas); |
2751 | xas_reset(&xas); | |
3e9a13da | 2752 | if (xas_load(&xas) != folio) |
baa355fd KS |
2753 | goto fail; |
2754 | } | |
2755 | ||
0139aa7b | 2756 | /* Prevent deferred_split_scan() touching ->_refcount */ |
364c1eeb | 2757 | spin_lock(&ds_queue->split_queue_lock); |
3e9a13da MWO |
2758 | if (folio_ref_freeze(folio, 1 + extra_pins)) { |
2759 | if (!list_empty(page_deferred_list(&folio->page))) { | |
364c1eeb | 2760 | ds_queue->split_queue_len--; |
3e9a13da | 2761 | list_del(page_deferred_list(&folio->page)); |
9a982250 | 2762 | } |
afb97172 | 2763 | spin_unlock(&ds_queue->split_queue_lock); |
06d3eff6 | 2764 | if (mapping) { |
3e9a13da | 2765 | int nr = folio_nr_pages(folio); |
bf9ecead | 2766 | |
3e9a13da MWO |
2767 | xas_split(&xas, folio, folio_order(folio)); |
2768 | if (folio_test_swapbacked(folio)) { | |
2769 | __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, | |
57b2847d | 2770 | -nr); |
1ca7554d | 2771 | } else { |
3e9a13da | 2772 | __lruvec_stat_mod_folio(folio, NR_FILE_THPS, |
bf9ecead | 2773 | -nr); |
1ca7554d MS |
2774 | filemap_nr_thps_dec(mapping); |
2775 | } | |
06d3eff6 KS |
2776 | } |
2777 | ||
b6769834 | 2778 | __split_huge_page(page, list, end); |
c4f9c701 | 2779 | ret = 0; |
e9b61f19 | 2780 | } else { |
364c1eeb | 2781 | spin_unlock(&ds_queue->split_queue_lock); |
504e070d YS |
2782 | fail: |
2783 | if (mapping) | |
6b24ca4a | 2784 | xas_unlock(&xas); |
b6769834 | 2785 | local_irq_enable(); |
4eecb8b9 | 2786 | remap_page(folio, folio_nr_pages(folio)); |
fd4a7ac3 | 2787 | ret = -EAGAIN; |
e9b61f19 KS |
2788 | } |
2789 | ||
2790 | out_unlock: | |
baa355fd KS |
2791 | if (anon_vma) { |
2792 | anon_vma_unlock_write(anon_vma); | |
2793 | put_anon_vma(anon_vma); | |
2794 | } | |
2795 | if (mapping) | |
2796 | i_mmap_unlock_read(mapping); | |
e9b61f19 | 2797 | out: |
69a37a8b | 2798 | xas_destroy(&xas); |
e9b61f19 KS |
2799 | count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); |
2800 | return ret; | |
2801 | } | |
9a982250 KS |
2802 | |
2803 | void free_transhuge_page(struct page *page) | |
2804 | { | |
87eaceb3 | 2805 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
9a982250 KS |
2806 | unsigned long flags; |
2807 | ||
364c1eeb | 2808 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2809 | if (!list_empty(page_deferred_list(page))) { |
364c1eeb | 2810 | ds_queue->split_queue_len--; |
9a982250 KS |
2811 | list_del(page_deferred_list(page)); |
2812 | } | |
364c1eeb | 2813 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2814 | free_compound_page(page); |
2815 | } | |
2816 | ||
2817 | void deferred_split_huge_page(struct page *page) | |
2818 | { | |
87eaceb3 YS |
2819 | struct deferred_split *ds_queue = get_deferred_split_queue(page); |
2820 | #ifdef CONFIG_MEMCG | |
bcfe06bf | 2821 | struct mem_cgroup *memcg = page_memcg(compound_head(page)); |
87eaceb3 | 2822 | #endif |
9a982250 KS |
2823 | unsigned long flags; |
2824 | ||
2825 | VM_BUG_ON_PAGE(!PageTransHuge(page), page); | |
2826 | ||
87eaceb3 YS |
2827 | /* |
2828 | * The try_to_unmap() in page reclaim path might reach here too, | |
2829 | * this may cause a race condition to corrupt deferred split queue. | |
2830 | * And, if page reclaim is already handling the same page, it is | |
2831 | * unnecessary to handle it again in shrinker. | |
2832 | * | |
2833 | * Check PageSwapCache to determine if the page is being | |
2834 | * handled by page reclaim since THP swap would add the page into | |
2835 | * swap cache before calling try_to_unmap(). | |
2836 | */ | |
2837 | if (PageSwapCache(page)) | |
2838 | return; | |
2839 | ||
364c1eeb | 2840 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2841 | if (list_empty(page_deferred_list(page))) { |
f9719a03 | 2842 | count_vm_event(THP_DEFERRED_SPLIT_PAGE); |
364c1eeb YS |
2843 | list_add_tail(page_deferred_list(page), &ds_queue->split_queue); |
2844 | ds_queue->split_queue_len++; | |
87eaceb3 YS |
2845 | #ifdef CONFIG_MEMCG |
2846 | if (memcg) | |
2bfd3637 YS |
2847 | set_shrinker_bit(memcg, page_to_nid(page), |
2848 | deferred_split_shrinker.id); | |
87eaceb3 | 2849 | #endif |
9a982250 | 2850 | } |
364c1eeb | 2851 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2852 | } |
2853 | ||
2854 | static unsigned long deferred_split_count(struct shrinker *shrink, | |
2855 | struct shrink_control *sc) | |
2856 | { | |
a3d0a918 | 2857 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2858 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
87eaceb3 YS |
2859 | |
2860 | #ifdef CONFIG_MEMCG | |
2861 | if (sc->memcg) | |
2862 | ds_queue = &sc->memcg->deferred_split_queue; | |
2863 | #endif | |
364c1eeb | 2864 | return READ_ONCE(ds_queue->split_queue_len); |
9a982250 KS |
2865 | } |
2866 | ||
2867 | static unsigned long deferred_split_scan(struct shrinker *shrink, | |
2868 | struct shrink_control *sc) | |
2869 | { | |
a3d0a918 | 2870 | struct pglist_data *pgdata = NODE_DATA(sc->nid); |
364c1eeb | 2871 | struct deferred_split *ds_queue = &pgdata->deferred_split_queue; |
9a982250 KS |
2872 | unsigned long flags; |
2873 | LIST_HEAD(list), *pos, *next; | |
2874 | struct page *page; | |
2875 | int split = 0; | |
2876 | ||
87eaceb3 YS |
2877 | #ifdef CONFIG_MEMCG |
2878 | if (sc->memcg) | |
2879 | ds_queue = &sc->memcg->deferred_split_queue; | |
2880 | #endif | |
2881 | ||
364c1eeb | 2882 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
9a982250 | 2883 | /* Take pin on all head pages to avoid freeing them under us */ |
364c1eeb | 2884 | list_for_each_safe(pos, next, &ds_queue->split_queue) { |
dfe5c51c | 2885 | page = list_entry((void *)pos, struct page, deferred_list); |
9a982250 | 2886 | page = compound_head(page); |
e3ae1953 KS |
2887 | if (get_page_unless_zero(page)) { |
2888 | list_move(page_deferred_list(page), &list); | |
2889 | } else { | |
2890 | /* We lost race with put_compound_page() */ | |
9a982250 | 2891 | list_del_init(page_deferred_list(page)); |
364c1eeb | 2892 | ds_queue->split_queue_len--; |
9a982250 | 2893 | } |
e3ae1953 KS |
2894 | if (!--sc->nr_to_scan) |
2895 | break; | |
9a982250 | 2896 | } |
364c1eeb | 2897 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); |
9a982250 KS |
2898 | |
2899 | list_for_each_safe(pos, next, &list) { | |
dfe5c51c | 2900 | page = list_entry((void *)pos, struct page, deferred_list); |
fa41b900 KS |
2901 | if (!trylock_page(page)) |
2902 | goto next; | |
9a982250 KS |
2903 | /* split_huge_page() removes page from list on success */ |
2904 | if (!split_huge_page(page)) | |
2905 | split++; | |
2906 | unlock_page(page); | |
fa41b900 | 2907 | next: |
9a982250 KS |
2908 | put_page(page); |
2909 | } | |
2910 | ||
364c1eeb YS |
2911 | spin_lock_irqsave(&ds_queue->split_queue_lock, flags); |
2912 | list_splice_tail(&list, &ds_queue->split_queue); | |
2913 | spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); | |
9a982250 | 2914 | |
cb8d68ec KS |
2915 | /* |
2916 | * Stop shrinker if we didn't split any page, but the queue is empty. | |
2917 | * This can happen if pages were freed under us. | |
2918 | */ | |
364c1eeb | 2919 | if (!split && list_empty(&ds_queue->split_queue)) |
cb8d68ec KS |
2920 | return SHRINK_STOP; |
2921 | return split; | |
9a982250 KS |
2922 | } |
2923 | ||
2924 | static struct shrinker deferred_split_shrinker = { | |
2925 | .count_objects = deferred_split_count, | |
2926 | .scan_objects = deferred_split_scan, | |
2927 | .seeks = DEFAULT_SEEKS, | |
87eaceb3 YS |
2928 | .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | |
2929 | SHRINKER_NONSLAB, | |
9a982250 | 2930 | }; |
49071d43 KS |
2931 | |
2932 | #ifdef CONFIG_DEBUG_FS | |
fa6c0231 | 2933 | static void split_huge_pages_all(void) |
49071d43 KS |
2934 | { |
2935 | struct zone *zone; | |
2936 | struct page *page; | |
2937 | unsigned long pfn, max_zone_pfn; | |
2938 | unsigned long total = 0, split = 0; | |
2939 | ||
fa6c0231 | 2940 | pr_debug("Split all THPs\n"); |
a17206da ML |
2941 | for_each_zone(zone) { |
2942 | if (!managed_zone(zone)) | |
2943 | continue; | |
49071d43 KS |
2944 | max_zone_pfn = zone_end_pfn(zone); |
2945 | for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { | |
a17206da | 2946 | int nr_pages; |
49071d43 | 2947 | |
2b7aa91b NH |
2948 | page = pfn_to_online_page(pfn); |
2949 | if (!page || !get_page_unless_zero(page)) | |
49071d43 KS |
2950 | continue; |
2951 | ||
2952 | if (zone != page_zone(page)) | |
2953 | goto next; | |
2954 | ||
baa355fd | 2955 | if (!PageHead(page) || PageHuge(page) || !PageLRU(page)) |
49071d43 KS |
2956 | goto next; |
2957 | ||
2958 | total++; | |
2959 | lock_page(page); | |
a17206da | 2960 | nr_pages = thp_nr_pages(page); |
49071d43 KS |
2961 | if (!split_huge_page(page)) |
2962 | split++; | |
a17206da | 2963 | pfn += nr_pages - 1; |
49071d43 KS |
2964 | unlock_page(page); |
2965 | next: | |
2966 | put_page(page); | |
fa6c0231 | 2967 | cond_resched(); |
49071d43 KS |
2968 | } |
2969 | } | |
2970 | ||
fa6c0231 ZY |
2971 | pr_debug("%lu of %lu THP split\n", split, total); |
2972 | } | |
49071d43 | 2973 | |
fa6c0231 ZY |
2974 | static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) |
2975 | { | |
2976 | return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || | |
2977 | is_vm_hugetlb_page(vma); | |
2978 | } | |
2979 | ||
2980 | static int split_huge_pages_pid(int pid, unsigned long vaddr_start, | |
2981 | unsigned long vaddr_end) | |
2982 | { | |
2983 | int ret = 0; | |
2984 | struct task_struct *task; | |
2985 | struct mm_struct *mm; | |
2986 | unsigned long total = 0, split = 0; | |
2987 | unsigned long addr; | |
2988 | ||
2989 | vaddr_start &= PAGE_MASK; | |
2990 | vaddr_end &= PAGE_MASK; | |
2991 | ||
2992 | /* Find the task_struct from pid */ | |
2993 | rcu_read_lock(); | |
2994 | task = find_task_by_vpid(pid); | |
2995 | if (!task) { | |
2996 | rcu_read_unlock(); | |
2997 | ret = -ESRCH; | |
2998 | goto out; | |
2999 | } | |
3000 | get_task_struct(task); | |
3001 | rcu_read_unlock(); | |
3002 | ||
3003 | /* Find the mm_struct */ | |
3004 | mm = get_task_mm(task); | |
3005 | put_task_struct(task); | |
3006 | ||
3007 | if (!mm) { | |
3008 | ret = -EINVAL; | |
3009 | goto out; | |
3010 | } | |
3011 | ||
3012 | pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", | |
3013 | pid, vaddr_start, vaddr_end); | |
3014 | ||
3015 | mmap_read_lock(mm); | |
3016 | /* | |
3017 | * always increase addr by PAGE_SIZE, since we could have a PTE page | |
3018 | * table filled with PTE-mapped THPs, each of which is distinct. | |
3019 | */ | |
3020 | for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { | |
74ba2b38 | 3021 | struct vm_area_struct *vma = vma_lookup(mm, addr); |
fa6c0231 ZY |
3022 | struct page *page; |
3023 | ||
74ba2b38 | 3024 | if (!vma) |
fa6c0231 ZY |
3025 | break; |
3026 | ||
3027 | /* skip special VMA and hugetlb VMA */ | |
3028 | if (vma_not_suitable_for_thp_split(vma)) { | |
3029 | addr = vma->vm_end; | |
3030 | continue; | |
3031 | } | |
3032 | ||
3033 | /* FOLL_DUMP to ignore special (like zero) pages */ | |
87d2762e | 3034 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
fa6c0231 | 3035 | |
f7091ed6 | 3036 | if (IS_ERR_OR_NULL(page)) |
fa6c0231 ZY |
3037 | continue; |
3038 | ||
3039 | if (!is_transparent_hugepage(page)) | |
3040 | goto next; | |
3041 | ||
3042 | total++; | |
d4b4084a | 3043 | if (!can_split_folio(page_folio(page), NULL)) |
fa6c0231 ZY |
3044 | goto next; |
3045 | ||
3046 | if (!trylock_page(page)) | |
3047 | goto next; | |
3048 | ||
3049 | if (!split_huge_page(page)) | |
3050 | split++; | |
3051 | ||
3052 | unlock_page(page); | |
3053 | next: | |
3054 | put_page(page); | |
3055 | cond_resched(); | |
3056 | } | |
3057 | mmap_read_unlock(mm); | |
3058 | mmput(mm); | |
3059 | ||
3060 | pr_debug("%lu of %lu THP split\n", split, total); | |
3061 | ||
3062 | out: | |
3063 | return ret; | |
49071d43 | 3064 | } |
fa6c0231 | 3065 | |
fbe37501 ZY |
3066 | static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, |
3067 | pgoff_t off_end) | |
3068 | { | |
3069 | struct filename *file; | |
3070 | struct file *candidate; | |
3071 | struct address_space *mapping; | |
3072 | int ret = -EINVAL; | |
3073 | pgoff_t index; | |
3074 | int nr_pages = 1; | |
3075 | unsigned long total = 0, split = 0; | |
3076 | ||
3077 | file = getname_kernel(file_path); | |
3078 | if (IS_ERR(file)) | |
3079 | return ret; | |
3080 | ||
3081 | candidate = file_open_name(file, O_RDONLY, 0); | |
3082 | if (IS_ERR(candidate)) | |
3083 | goto out; | |
3084 | ||
3085 | pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", | |
3086 | file_path, off_start, off_end); | |
3087 | ||
3088 | mapping = candidate->f_mapping; | |
3089 | ||
3090 | for (index = off_start; index < off_end; index += nr_pages) { | |
9ee2c086 MWO |
3091 | struct folio *folio = __filemap_get_folio(mapping, index, |
3092 | FGP_ENTRY, 0); | |
fbe37501 ZY |
3093 | |
3094 | nr_pages = 1; | |
9ee2c086 | 3095 | if (xa_is_value(folio) || !folio) |
fbe37501 ZY |
3096 | continue; |
3097 | ||
9ee2c086 | 3098 | if (!folio_test_large(folio)) |
fbe37501 ZY |
3099 | goto next; |
3100 | ||
3101 | total++; | |
9ee2c086 | 3102 | nr_pages = folio_nr_pages(folio); |
fbe37501 | 3103 | |
9ee2c086 | 3104 | if (!folio_trylock(folio)) |
fbe37501 ZY |
3105 | goto next; |
3106 | ||
9ee2c086 | 3107 | if (!split_folio(folio)) |
fbe37501 ZY |
3108 | split++; |
3109 | ||
9ee2c086 | 3110 | folio_unlock(folio); |
fbe37501 | 3111 | next: |
9ee2c086 | 3112 | folio_put(folio); |
fbe37501 ZY |
3113 | cond_resched(); |
3114 | } | |
3115 | ||
3116 | filp_close(candidate, NULL); | |
3117 | ret = 0; | |
3118 | ||
3119 | pr_debug("%lu of %lu file-backed THP split\n", split, total); | |
3120 | out: | |
3121 | putname(file); | |
3122 | return ret; | |
3123 | } | |
3124 | ||
fa6c0231 ZY |
3125 | #define MAX_INPUT_BUF_SZ 255 |
3126 | ||
3127 | static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, | |
3128 | size_t count, loff_t *ppops) | |
3129 | { | |
3130 | static DEFINE_MUTEX(split_debug_mutex); | |
3131 | ssize_t ret; | |
fbe37501 ZY |
3132 | /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */ |
3133 | char input_buf[MAX_INPUT_BUF_SZ]; | |
fa6c0231 ZY |
3134 | int pid; |
3135 | unsigned long vaddr_start, vaddr_end; | |
3136 | ||
3137 | ret = mutex_lock_interruptible(&split_debug_mutex); | |
3138 | if (ret) | |
3139 | return ret; | |
3140 | ||
3141 | ret = -EFAULT; | |
3142 | ||
3143 | memset(input_buf, 0, MAX_INPUT_BUF_SZ); | |
3144 | if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) | |
3145 | goto out; | |
3146 | ||
3147 | input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; | |
fbe37501 ZY |
3148 | |
3149 | if (input_buf[0] == '/') { | |
3150 | char *tok; | |
3151 | char *buf = input_buf; | |
3152 | char file_path[MAX_INPUT_BUF_SZ]; | |
3153 | pgoff_t off_start = 0, off_end = 0; | |
3154 | size_t input_len = strlen(input_buf); | |
3155 | ||
3156 | tok = strsep(&buf, ","); | |
3157 | if (tok) { | |
1212e00c | 3158 | strcpy(file_path, tok); |
fbe37501 ZY |
3159 | } else { |
3160 | ret = -EINVAL; | |
3161 | goto out; | |
3162 | } | |
3163 | ||
3164 | ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end); | |
3165 | if (ret != 2) { | |
3166 | ret = -EINVAL; | |
3167 | goto out; | |
3168 | } | |
3169 | ret = split_huge_pages_in_file(file_path, off_start, off_end); | |
3170 | if (!ret) | |
3171 | ret = input_len; | |
3172 | ||
3173 | goto out; | |
3174 | } | |
3175 | ||
fa6c0231 ZY |
3176 | ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); |
3177 | if (ret == 1 && pid == 1) { | |
3178 | split_huge_pages_all(); | |
3179 | ret = strlen(input_buf); | |
3180 | goto out; | |
3181 | } else if (ret != 3) { | |
3182 | ret = -EINVAL; | |
3183 | goto out; | |
3184 | } | |
3185 | ||
3186 | ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); | |
3187 | if (!ret) | |
3188 | ret = strlen(input_buf); | |
3189 | out: | |
3190 | mutex_unlock(&split_debug_mutex); | |
3191 | return ret; | |
3192 | ||
3193 | } | |
3194 | ||
3195 | static const struct file_operations split_huge_pages_fops = { | |
3196 | .owner = THIS_MODULE, | |
3197 | .write = split_huge_pages_write, | |
3198 | .llseek = no_llseek, | |
3199 | }; | |
49071d43 KS |
3200 | |
3201 | static int __init split_huge_pages_debugfs(void) | |
3202 | { | |
d9f7979c GKH |
3203 | debugfs_create_file("split_huge_pages", 0200, NULL, NULL, |
3204 | &split_huge_pages_fops); | |
49071d43 KS |
3205 | return 0; |
3206 | } | |
3207 | late_initcall(split_huge_pages_debugfs); | |
3208 | #endif | |
616b8371 ZY |
3209 | |
3210 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION | |
7f5abe60 | 3211 | int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, |
616b8371 ZY |
3212 | struct page *page) |
3213 | { | |
3214 | struct vm_area_struct *vma = pvmw->vma; | |
3215 | struct mm_struct *mm = vma->vm_mm; | |
3216 | unsigned long address = pvmw->address; | |
6c287605 | 3217 | bool anon_exclusive; |
616b8371 ZY |
3218 | pmd_t pmdval; |
3219 | swp_entry_t entry; | |
ab6e3d09 | 3220 | pmd_t pmdswp; |
616b8371 ZY |
3221 | |
3222 | if (!(pvmw->pmd && !pvmw->pte)) | |
7f5abe60 | 3223 | return 0; |
616b8371 | 3224 | |
616b8371 | 3225 | flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); |
8a8683ad | 3226 | pmdval = pmdp_invalidate(vma, address, pvmw->pmd); |
6c287605 | 3227 | |
088b8aa5 | 3228 | /* See page_try_share_anon_rmap(): invalidate PMD first. */ |
6c287605 DH |
3229 | anon_exclusive = PageAnon(page) && PageAnonExclusive(page); |
3230 | if (anon_exclusive && page_try_share_anon_rmap(page)) { | |
3231 | set_pmd_at(mm, address, pvmw->pmd, pmdval); | |
7f5abe60 | 3232 | return -EBUSY; |
6c287605 DH |
3233 | } |
3234 | ||
616b8371 ZY |
3235 | if (pmd_dirty(pmdval)) |
3236 | set_page_dirty(page); | |
4dd845b5 AP |
3237 | if (pmd_write(pmdval)) |
3238 | entry = make_writable_migration_entry(page_to_pfn(page)); | |
6c287605 DH |
3239 | else if (anon_exclusive) |
3240 | entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); | |
4dd845b5 AP |
3241 | else |
3242 | entry = make_readable_migration_entry(page_to_pfn(page)); | |
2e346877 PX |
3243 | if (pmd_young(pmdval)) |
3244 | entry = make_migration_entry_young(entry); | |
3245 | if (pmd_dirty(pmdval)) | |
3246 | entry = make_migration_entry_dirty(entry); | |
ab6e3d09 NH |
3247 | pmdswp = swp_entry_to_pmd(entry); |
3248 | if (pmd_soft_dirty(pmdval)) | |
3249 | pmdswp = pmd_swp_mksoft_dirty(pmdswp); | |
3250 | set_pmd_at(mm, address, pvmw->pmd, pmdswp); | |
cea86fe2 | 3251 | page_remove_rmap(page, vma, true); |
616b8371 | 3252 | put_page(page); |
283fd6fe | 3253 | trace_set_migration_pmd(address, pmd_val(pmdswp)); |
7f5abe60 DH |
3254 | |
3255 | return 0; | |
616b8371 ZY |
3256 | } |
3257 | ||
3258 | void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) | |
3259 | { | |
3260 | struct vm_area_struct *vma = pvmw->vma; | |
3261 | struct mm_struct *mm = vma->vm_mm; | |
3262 | unsigned long address = pvmw->address; | |
4fba8f2a | 3263 | unsigned long haddr = address & HPAGE_PMD_MASK; |
616b8371 ZY |
3264 | pmd_t pmde; |
3265 | swp_entry_t entry; | |
3266 | ||
3267 | if (!(pvmw->pmd && !pvmw->pte)) | |
3268 | return; | |
3269 | ||
3270 | entry = pmd_to_swp_entry(*pvmw->pmd); | |
3271 | get_page(new); | |
2e346877 | 3272 | pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); |
ab6e3d09 NH |
3273 | if (pmd_swp_soft_dirty(*pvmw->pmd)) |
3274 | pmde = pmd_mksoft_dirty(pmde); | |
4dd845b5 | 3275 | if (is_writable_migration_entry(entry)) |
f55e1014 | 3276 | pmde = maybe_pmd_mkwrite(pmde, vma); |
8f34f1ea PX |
3277 | if (pmd_swp_uffd_wp(*pvmw->pmd)) |
3278 | pmde = pmd_wrprotect(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); | |
616b8371 | 3284 | |
6c287605 DH |
3285 | if (PageAnon(new)) { |
3286 | rmap_t rmap_flags = RMAP_COMPOUND; | |
3287 | ||
3288 | if (!is_readable_migration_entry(entry)) | |
3289 | rmap_flags |= RMAP_EXCLUSIVE; | |
3290 | ||
4fba8f2a | 3291 | page_add_anon_rmap(new, vma, haddr, rmap_flags); |
6c287605 | 3292 | } else { |
cea86fe2 | 3293 | page_add_file_rmap(new, vma, true); |
6c287605 DH |
3294 | } |
3295 | VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); | |
4fba8f2a | 3296 | set_pmd_at(mm, haddr, pvmw->pmd, pmde); |
5cbcf225 MS |
3297 | |
3298 | /* No need to invalidate - it was non-present before */ | |
616b8371 | 3299 | update_mmu_cache_pmd(vma, address, pvmw->pmd); |
283fd6fe | 3300 | trace_remove_migration_pmd(address, pmd_val(pmde)); |
616b8371 ZY |
3301 | } |
3302 | #endif |