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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
b20a3503 | 2 | /* |
14e0f9bc | 3 | * Memory Migration functionality - linux/mm/migrate.c |
b20a3503 CL |
4 | * |
5 | * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter | |
6 | * | |
7 | * Page migration was first developed in the context of the memory hotplug | |
8 | * project. The main authors of the migration code are: | |
9 | * | |
10 | * IWAMOTO Toshihiro <iwamoto@valinux.co.jp> | |
11 | * Hirokazu Takahashi <taka@valinux.co.jp> | |
12 | * Dave Hansen <haveblue@us.ibm.com> | |
cde53535 | 13 | * Christoph Lameter |
b20a3503 CL |
14 | */ |
15 | ||
16 | #include <linux/migrate.h> | |
b95f1b31 | 17 | #include <linux/export.h> |
b20a3503 | 18 | #include <linux/swap.h> |
0697212a | 19 | #include <linux/swapops.h> |
b20a3503 | 20 | #include <linux/pagemap.h> |
e23ca00b | 21 | #include <linux/buffer_head.h> |
b20a3503 | 22 | #include <linux/mm_inline.h> |
b488893a | 23 | #include <linux/nsproxy.h> |
b20a3503 | 24 | #include <linux/pagevec.h> |
e9995ef9 | 25 | #include <linux/ksm.h> |
b20a3503 CL |
26 | #include <linux/rmap.h> |
27 | #include <linux/topology.h> | |
28 | #include <linux/cpu.h> | |
29 | #include <linux/cpuset.h> | |
04e62a29 | 30 | #include <linux/writeback.h> |
742755a1 CL |
31 | #include <linux/mempolicy.h> |
32 | #include <linux/vmalloc.h> | |
86c3a764 | 33 | #include <linux/security.h> |
42cb14b1 | 34 | #include <linux/backing-dev.h> |
bda807d4 | 35 | #include <linux/compaction.h> |
4f5ca265 | 36 | #include <linux/syscalls.h> |
7addf443 | 37 | #include <linux/compat.h> |
290408d4 | 38 | #include <linux/hugetlb.h> |
8e6ac7fa | 39 | #include <linux/hugetlb_cgroup.h> |
5a0e3ad6 | 40 | #include <linux/gfp.h> |
df6ad698 | 41 | #include <linux/pfn_t.h> |
a5430dda | 42 | #include <linux/memremap.h> |
8315ada7 | 43 | #include <linux/userfaultfd_k.h> |
bf6bddf1 | 44 | #include <linux/balloon_compaction.h> |
33c3fc71 | 45 | #include <linux/page_idle.h> |
d435edca | 46 | #include <linux/page_owner.h> |
6e84f315 | 47 | #include <linux/sched/mm.h> |
197e7e52 | 48 | #include <linux/ptrace.h> |
34290e2c | 49 | #include <linux/oom.h> |
884a6e5d | 50 | #include <linux/memory.h> |
ac16ec83 | 51 | #include <linux/random.h> |
c574bbe9 | 52 | #include <linux/sched/sysctl.h> |
467b171a | 53 | #include <linux/memory-tiers.h> |
b20a3503 | 54 | |
0d1836c3 MN |
55 | #include <asm/tlbflush.h> |
56 | ||
7b2a2d4a MG |
57 | #include <trace/events/migrate.h> |
58 | ||
b20a3503 CL |
59 | #include "internal.h" |
60 | ||
cd775580 | 61 | bool isolate_movable_page(struct page *page, isolate_mode_t mode) |
bda807d4 | 62 | { |
19979497 | 63 | struct folio *folio = folio_get_nontail_page(page); |
68f2736a | 64 | const struct movable_operations *mops; |
bda807d4 MK |
65 | |
66 | /* | |
67 | * Avoid burning cycles with pages that are yet under __free_pages(), | |
68 | * or just got freed under us. | |
69 | * | |
70 | * In case we 'win' a race for a movable page being freed under us and | |
71 | * raise its refcount preventing __free_pages() from doing its job | |
72 | * the put_page() at the end of this block will take care of | |
73 | * release this page, thus avoiding a nasty leakage. | |
74 | */ | |
19979497 | 75 | if (!folio) |
bda807d4 MK |
76 | goto out; |
77 | ||
19979497 VMO |
78 | if (unlikely(folio_test_slab(folio))) |
79 | goto out_putfolio; | |
8b881763 VB |
80 | /* Pairs with smp_wmb() in slab freeing, e.g. SLUB's __free_slab() */ |
81 | smp_rmb(); | |
bda807d4 | 82 | /* |
8b881763 VB |
83 | * Check movable flag before taking the page lock because |
84 | * we use non-atomic bitops on newly allocated page flags so | |
85 | * unconditionally grabbing the lock ruins page's owner side. | |
bda807d4 | 86 | */ |
19979497 VMO |
87 | if (unlikely(!__folio_test_movable(folio))) |
88 | goto out_putfolio; | |
8b881763 VB |
89 | /* Pairs with smp_wmb() in slab allocation, e.g. SLUB's alloc_slab_page() */ |
90 | smp_rmb(); | |
19979497 VMO |
91 | if (unlikely(folio_test_slab(folio))) |
92 | goto out_putfolio; | |
8b881763 | 93 | |
bda807d4 MK |
94 | /* |
95 | * As movable pages are not isolated from LRU lists, concurrent | |
96 | * compaction threads can race against page migration functions | |
97 | * as well as race against the releasing a page. | |
98 | * | |
99 | * In order to avoid having an already isolated movable page | |
100 | * being (wrongly) re-isolated while it is under migration, | |
101 | * or to avoid attempting to isolate pages being released, | |
102 | * lets be sure we have the page lock | |
103 | * before proceeding with the movable page isolation steps. | |
104 | */ | |
19979497 VMO |
105 | if (unlikely(!folio_trylock(folio))) |
106 | goto out_putfolio; | |
bda807d4 | 107 | |
19979497 | 108 | if (!folio_test_movable(folio) || folio_test_isolated(folio)) |
bda807d4 MK |
109 | goto out_no_isolated; |
110 | ||
19979497 VMO |
111 | mops = folio_movable_ops(folio); |
112 | VM_BUG_ON_FOLIO(!mops, folio); | |
bda807d4 | 113 | |
19979497 | 114 | if (!mops->isolate_page(&folio->page, mode)) |
bda807d4 MK |
115 | goto out_no_isolated; |
116 | ||
117 | /* Driver shouldn't use PG_isolated bit of page->flags */ | |
19979497 VMO |
118 | WARN_ON_ONCE(folio_test_isolated(folio)); |
119 | folio_set_isolated(folio); | |
120 | folio_unlock(folio); | |
bda807d4 | 121 | |
cd775580 | 122 | return true; |
bda807d4 MK |
123 | |
124 | out_no_isolated: | |
19979497 VMO |
125 | folio_unlock(folio); |
126 | out_putfolio: | |
127 | folio_put(folio); | |
bda807d4 | 128 | out: |
cd775580 | 129 | return false; |
bda807d4 MK |
130 | } |
131 | ||
280d724a | 132 | static void putback_movable_folio(struct folio *folio) |
bda807d4 | 133 | { |
280d724a | 134 | const struct movable_operations *mops = folio_movable_ops(folio); |
bda807d4 | 135 | |
280d724a VMO |
136 | mops->putback_page(&folio->page); |
137 | folio_clear_isolated(folio); | |
bda807d4 MK |
138 | } |
139 | ||
5733c7d1 RA |
140 | /* |
141 | * Put previously isolated pages back onto the appropriate lists | |
142 | * from where they were once taken off for compaction/migration. | |
143 | * | |
59c82b70 JK |
144 | * This function shall be used whenever the isolated pageset has been |
145 | * built from lru, balloon, hugetlbfs page. See isolate_migratepages_range() | |
7ce82f4c | 146 | * and isolate_hugetlb(). |
5733c7d1 RA |
147 | */ |
148 | void putback_movable_pages(struct list_head *l) | |
149 | { | |
280d724a VMO |
150 | struct folio *folio; |
151 | struct folio *folio2; | |
5733c7d1 | 152 | |
280d724a VMO |
153 | list_for_each_entry_safe(folio, folio2, l, lru) { |
154 | if (unlikely(folio_test_hugetlb(folio))) { | |
155 | folio_putback_active_hugetlb(folio); | |
31caf665 NH |
156 | continue; |
157 | } | |
280d724a | 158 | list_del(&folio->lru); |
bda807d4 | 159 | /* |
280d724a VMO |
160 | * We isolated non-lru movable folio so here we can use |
161 | * __PageMovable because LRU folio's mapping cannot have | |
bda807d4 MK |
162 | * PAGE_MAPPING_MOVABLE. |
163 | */ | |
280d724a VMO |
164 | if (unlikely(__folio_test_movable(folio))) { |
165 | VM_BUG_ON_FOLIO(!folio_test_isolated(folio), folio); | |
166 | folio_lock(folio); | |
167 | if (folio_test_movable(folio)) | |
168 | putback_movable_folio(folio); | |
bda807d4 | 169 | else |
280d724a VMO |
170 | folio_clear_isolated(folio); |
171 | folio_unlock(folio); | |
172 | folio_put(folio); | |
bda807d4 | 173 | } else { |
280d724a VMO |
174 | node_stat_mod_folio(folio, NR_ISOLATED_ANON + |
175 | folio_is_file_lru(folio), -folio_nr_pages(folio)); | |
176 | folio_putback_lru(folio); | |
bda807d4 | 177 | } |
b20a3503 | 178 | } |
b20a3503 CL |
179 | } |
180 | ||
0697212a CL |
181 | /* |
182 | * Restore a potential migration pte to a working pte entry | |
183 | */ | |
2f031c6f MWO |
184 | static bool remove_migration_pte(struct folio *folio, |
185 | struct vm_area_struct *vma, unsigned long addr, void *old) | |
0697212a | 186 | { |
4eecb8b9 | 187 | DEFINE_FOLIO_VMA_WALK(pvmw, old, vma, addr, PVMW_SYNC | PVMW_MIGRATION); |
0697212a | 188 | |
3fe87967 | 189 | while (page_vma_mapped_walk(&pvmw)) { |
6c287605 | 190 | rmap_t rmap_flags = RMAP_NONE; |
c33c7948 | 191 | pte_t old_pte; |
4eecb8b9 MWO |
192 | pte_t pte; |
193 | swp_entry_t entry; | |
194 | struct page *new; | |
195 | unsigned long idx = 0; | |
196 | ||
197 | /* pgoff is invalid for ksm pages, but they are never large */ | |
198 | if (folio_test_large(folio) && !folio_test_hugetlb(folio)) | |
199 | idx = linear_page_index(vma, pvmw.address) - pvmw.pgoff; | |
200 | new = folio_page(folio, idx); | |
0697212a | 201 | |
616b8371 ZY |
202 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
203 | /* PMD-mapped THP migration entry */ | |
204 | if (!pvmw.pte) { | |
4eecb8b9 MWO |
205 | VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) || |
206 | !folio_test_pmd_mappable(folio), folio); | |
616b8371 ZY |
207 | remove_migration_pmd(&pvmw, new); |
208 | continue; | |
209 | } | |
210 | #endif | |
211 | ||
4eecb8b9 | 212 | folio_get(folio); |
2e346877 | 213 | pte = mk_pte(new, READ_ONCE(vma->vm_page_prot)); |
c33c7948 RR |
214 | old_pte = ptep_get(pvmw.pte); |
215 | if (pte_swp_soft_dirty(old_pte)) | |
3fe87967 | 216 | pte = pte_mksoft_dirty(pte); |
0697212a | 217 | |
c33c7948 | 218 | entry = pte_to_swp_entry(old_pte); |
2e346877 PX |
219 | if (!is_migration_entry_young(entry)) |
220 | pte = pte_mkold(pte); | |
221 | if (folio_test_dirty(folio) && is_migration_entry_dirty(entry)) | |
222 | pte = pte_mkdirty(pte); | |
4dd845b5 | 223 | if (is_writable_migration_entry(entry)) |
f3ebdf04 | 224 | pte = pte_mkwrite(pte); |
c33c7948 | 225 | else if (pte_swp_uffd_wp(old_pte)) |
f45ec5ff | 226 | pte = pte_mkuffd_wp(pte); |
d3cb8bf6 | 227 | |
6c287605 DH |
228 | if (folio_test_anon(folio) && !is_readable_migration_entry(entry)) |
229 | rmap_flags |= RMAP_EXCLUSIVE; | |
230 | ||
6128763f | 231 | if (unlikely(is_device_private_page(new))) { |
4dd845b5 AP |
232 | if (pte_write(pte)) |
233 | entry = make_writable_device_private_entry( | |
234 | page_to_pfn(new)); | |
235 | else | |
236 | entry = make_readable_device_private_entry( | |
237 | page_to_pfn(new)); | |
6128763f | 238 | pte = swp_entry_to_pte(entry); |
c33c7948 | 239 | if (pte_swp_soft_dirty(old_pte)) |
3d321bf8 | 240 | pte = pte_swp_mksoft_dirty(pte); |
c33c7948 | 241 | if (pte_swp_uffd_wp(old_pte)) |
6128763f | 242 | pte = pte_swp_mkuffd_wp(pte); |
d2b2c6dd | 243 | } |
a5430dda | 244 | |
3ef8fd7f | 245 | #ifdef CONFIG_HUGETLB_PAGE |
4eecb8b9 | 246 | if (folio_test_hugetlb(folio)) { |
79c1c594 CL |
247 | unsigned int shift = huge_page_shift(hstate_vma(vma)); |
248 | ||
79c1c594 | 249 | pte = arch_make_huge_pte(pte, shift, vma->vm_flags); |
4eecb8b9 | 250 | if (folio_test_anon(folio)) |
28c5209d | 251 | hugepage_add_anon_rmap(new, vma, pvmw.address, |
6c287605 | 252 | rmap_flags); |
3fe87967 | 253 | else |
fb3d824d | 254 | page_dup_file_rmap(new, true); |
1eba86c0 | 255 | set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); |
383321ab AK |
256 | } else |
257 | #endif | |
258 | { | |
4eecb8b9 | 259 | if (folio_test_anon(folio)) |
f1e2db12 | 260 | page_add_anon_rmap(new, vma, pvmw.address, |
6c287605 | 261 | rmap_flags); |
383321ab | 262 | else |
cea86fe2 | 263 | page_add_file_rmap(new, vma, false); |
1eba86c0 | 264 | set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); |
383321ab | 265 | } |
b7435507 | 266 | if (vma->vm_flags & VM_LOCKED) |
96f97c43 | 267 | mlock_drain_local(); |
e125fe40 | 268 | |
4cc79b33 AK |
269 | trace_remove_migration_pte(pvmw.address, pte_val(pte), |
270 | compound_order(new)); | |
271 | ||
3fe87967 KS |
272 | /* No need to invalidate - it was non-present before */ |
273 | update_mmu_cache(vma, pvmw.address, pvmw.pte); | |
274 | } | |
51afb12b | 275 | |
e4b82222 | 276 | return true; |
0697212a CL |
277 | } |
278 | ||
04e62a29 CL |
279 | /* |
280 | * Get rid of all migration entries and replace them by | |
281 | * references to the indicated page. | |
282 | */ | |
4eecb8b9 | 283 | void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked) |
04e62a29 | 284 | { |
051ac83a JK |
285 | struct rmap_walk_control rwc = { |
286 | .rmap_one = remove_migration_pte, | |
4eecb8b9 | 287 | .arg = src, |
051ac83a JK |
288 | }; |
289 | ||
e388466d | 290 | if (locked) |
2f031c6f | 291 | rmap_walk_locked(dst, &rwc); |
e388466d | 292 | else |
2f031c6f | 293 | rmap_walk(dst, &rwc); |
04e62a29 CL |
294 | } |
295 | ||
0697212a CL |
296 | /* |
297 | * Something used the pte of a page under migration. We need to | |
298 | * get to the page and wait until migration is finished. | |
299 | * When we return from this function the fault will be retried. | |
0697212a | 300 | */ |
0cb8fd4d HD |
301 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, |
302 | unsigned long address) | |
0697212a | 303 | { |
0cb8fd4d HD |
304 | spinlock_t *ptl; |
305 | pte_t *ptep; | |
30dad309 | 306 | pte_t pte; |
0697212a | 307 | swp_entry_t entry; |
0697212a | 308 | |
0cb8fd4d | 309 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
04dee9e8 HD |
310 | if (!ptep) |
311 | return; | |
312 | ||
c33c7948 | 313 | pte = ptep_get(ptep); |
0cb8fd4d HD |
314 | pte_unmap(ptep); |
315 | ||
0697212a CL |
316 | if (!is_swap_pte(pte)) |
317 | goto out; | |
318 | ||
319 | entry = pte_to_swp_entry(pte); | |
320 | if (!is_migration_entry(entry)) | |
321 | goto out; | |
322 | ||
0cb8fd4d | 323 | migration_entry_wait_on_locked(entry, ptl); |
0697212a CL |
324 | return; |
325 | out: | |
0cb8fd4d | 326 | spin_unlock(ptl); |
30dad309 NH |
327 | } |
328 | ||
ad1ac596 | 329 | #ifdef CONFIG_HUGETLB_PAGE |
fcd48540 PX |
330 | /* |
331 | * The vma read lock must be held upon entry. Holding that lock prevents either | |
332 | * the pte or the ptl from being freed. | |
333 | * | |
334 | * This function will release the vma lock before returning. | |
335 | */ | |
0cb8fd4d | 336 | void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *ptep) |
30dad309 | 337 | { |
0cb8fd4d | 338 | spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, ptep); |
ad1ac596 ML |
339 | pte_t pte; |
340 | ||
fcd48540 | 341 | hugetlb_vma_assert_locked(vma); |
ad1ac596 ML |
342 | spin_lock(ptl); |
343 | pte = huge_ptep_get(ptep); | |
344 | ||
fcd48540 | 345 | if (unlikely(!is_hugetlb_entry_migration(pte))) { |
ad1ac596 | 346 | spin_unlock(ptl); |
fcd48540 PX |
347 | hugetlb_vma_unlock_read(vma); |
348 | } else { | |
349 | /* | |
350 | * If migration entry existed, safe to release vma lock | |
351 | * here because the pgtable page won't be freed without the | |
352 | * pgtable lock released. See comment right above pgtable | |
353 | * lock release in migration_entry_wait_on_locked(). | |
354 | */ | |
355 | hugetlb_vma_unlock_read(vma); | |
0cb8fd4d | 356 | migration_entry_wait_on_locked(pte_to_swp_entry(pte), ptl); |
fcd48540 | 357 | } |
30dad309 | 358 | } |
ad1ac596 ML |
359 | #endif |
360 | ||
616b8371 ZY |
361 | #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION |
362 | void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) | |
363 | { | |
364 | spinlock_t *ptl; | |
616b8371 ZY |
365 | |
366 | ptl = pmd_lock(mm, pmd); | |
367 | if (!is_pmd_migration_entry(*pmd)) | |
368 | goto unlock; | |
0cb8fd4d | 369 | migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), ptl); |
616b8371 ZY |
370 | return; |
371 | unlock: | |
372 | spin_unlock(ptl); | |
373 | } | |
374 | #endif | |
375 | ||
108ca835 MWO |
376 | static int folio_expected_refs(struct address_space *mapping, |
377 | struct folio *folio) | |
0b3901b3 | 378 | { |
108ca835 MWO |
379 | int refs = 1; |
380 | if (!mapping) | |
381 | return refs; | |
0b3901b3 | 382 | |
108ca835 MWO |
383 | refs += folio_nr_pages(folio); |
384 | if (folio_test_private(folio)) | |
385 | refs++; | |
386 | ||
387 | return refs; | |
0b3901b3 JK |
388 | } |
389 | ||
b20a3503 | 390 | /* |
c3fcf8a5 | 391 | * Replace the page in the mapping. |
5b5c7120 CL |
392 | * |
393 | * The number of remaining references must be: | |
394 | * 1 for anonymous pages without a mapping | |
395 | * 2 for pages with a mapping | |
266cf658 | 396 | * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. |
b20a3503 | 397 | */ |
3417013e MWO |
398 | int folio_migrate_mapping(struct address_space *mapping, |
399 | struct folio *newfolio, struct folio *folio, int extra_count) | |
b20a3503 | 400 | { |
3417013e | 401 | XA_STATE(xas, &mapping->i_pages, folio_index(folio)); |
42cb14b1 HD |
402 | struct zone *oldzone, *newzone; |
403 | int dirty; | |
108ca835 | 404 | int expected_count = folio_expected_refs(mapping, folio) + extra_count; |
3417013e | 405 | long nr = folio_nr_pages(folio); |
8763cb45 | 406 | |
6c5240ae | 407 | if (!mapping) { |
0e8c7d0f | 408 | /* Anonymous page without mapping */ |
3417013e | 409 | if (folio_ref_count(folio) != expected_count) |
6c5240ae | 410 | return -EAGAIN; |
cf4b769a HD |
411 | |
412 | /* No turning back from here */ | |
3417013e MWO |
413 | newfolio->index = folio->index; |
414 | newfolio->mapping = folio->mapping; | |
415 | if (folio_test_swapbacked(folio)) | |
416 | __folio_set_swapbacked(newfolio); | |
cf4b769a | 417 | |
78bd5209 | 418 | return MIGRATEPAGE_SUCCESS; |
6c5240ae CL |
419 | } |
420 | ||
3417013e MWO |
421 | oldzone = folio_zone(folio); |
422 | newzone = folio_zone(newfolio); | |
42cb14b1 | 423 | |
89eb946a | 424 | xas_lock_irq(&xas); |
3417013e | 425 | if (!folio_ref_freeze(folio, expected_count)) { |
89eb946a | 426 | xas_unlock_irq(&xas); |
e286781d NP |
427 | return -EAGAIN; |
428 | } | |
429 | ||
b20a3503 | 430 | /* |
3417013e | 431 | * Now we know that no one else is looking at the folio: |
cf4b769a | 432 | * no turning back from here. |
b20a3503 | 433 | */ |
3417013e MWO |
434 | newfolio->index = folio->index; |
435 | newfolio->mapping = folio->mapping; | |
436 | folio_ref_add(newfolio, nr); /* add cache reference */ | |
437 | if (folio_test_swapbacked(folio)) { | |
438 | __folio_set_swapbacked(newfolio); | |
439 | if (folio_test_swapcache(folio)) { | |
440 | folio_set_swapcache(newfolio); | |
441 | newfolio->private = folio_get_private(folio); | |
6326fec1 NP |
442 | } |
443 | } else { | |
3417013e | 444 | VM_BUG_ON_FOLIO(folio_test_swapcache(folio), folio); |
b20a3503 CL |
445 | } |
446 | ||
42cb14b1 | 447 | /* Move dirty while page refs frozen and newpage not yet exposed */ |
3417013e | 448 | dirty = folio_test_dirty(folio); |
42cb14b1 | 449 | if (dirty) { |
3417013e MWO |
450 | folio_clear_dirty(folio); |
451 | folio_set_dirty(newfolio); | |
42cb14b1 HD |
452 | } |
453 | ||
3417013e | 454 | xas_store(&xas, newfolio); |
7cf9c2c7 NP |
455 | |
456 | /* | |
937a94c9 JG |
457 | * Drop cache reference from old page by unfreezing |
458 | * to one less reference. | |
7cf9c2c7 NP |
459 | * We know this isn't the last reference. |
460 | */ | |
3417013e | 461 | folio_ref_unfreeze(folio, expected_count - nr); |
7cf9c2c7 | 462 | |
89eb946a | 463 | xas_unlock(&xas); |
42cb14b1 HD |
464 | /* Leave irq disabled to prevent preemption while updating stats */ |
465 | ||
0e8c7d0f CL |
466 | /* |
467 | * If moved to a different zone then also account | |
468 | * the page for that zone. Other VM counters will be | |
469 | * taken care of when we establish references to the | |
470 | * new page and drop references to the old page. | |
471 | * | |
472 | * Note that anonymous pages are accounted for | |
4b9d0fab | 473 | * via NR_FILE_PAGES and NR_ANON_MAPPED if they |
0e8c7d0f CL |
474 | * are mapped to swap space. |
475 | */ | |
42cb14b1 | 476 | if (newzone != oldzone) { |
0d1c2072 JW |
477 | struct lruvec *old_lruvec, *new_lruvec; |
478 | struct mem_cgroup *memcg; | |
479 | ||
3417013e | 480 | memcg = folio_memcg(folio); |
0d1c2072 JW |
481 | old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat); |
482 | new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat); | |
483 | ||
5c447d27 SB |
484 | __mod_lruvec_state(old_lruvec, NR_FILE_PAGES, -nr); |
485 | __mod_lruvec_state(new_lruvec, NR_FILE_PAGES, nr); | |
3417013e | 486 | if (folio_test_swapbacked(folio) && !folio_test_swapcache(folio)) { |
5c447d27 SB |
487 | __mod_lruvec_state(old_lruvec, NR_SHMEM, -nr); |
488 | __mod_lruvec_state(new_lruvec, NR_SHMEM, nr); | |
42cb14b1 | 489 | } |
b6038942 | 490 | #ifdef CONFIG_SWAP |
3417013e | 491 | if (folio_test_swapcache(folio)) { |
b6038942 SB |
492 | __mod_lruvec_state(old_lruvec, NR_SWAPCACHE, -nr); |
493 | __mod_lruvec_state(new_lruvec, NR_SWAPCACHE, nr); | |
494 | } | |
495 | #endif | |
f56753ac | 496 | if (dirty && mapping_can_writeback(mapping)) { |
5c447d27 SB |
497 | __mod_lruvec_state(old_lruvec, NR_FILE_DIRTY, -nr); |
498 | __mod_zone_page_state(oldzone, NR_ZONE_WRITE_PENDING, -nr); | |
499 | __mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr); | |
500 | __mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr); | |
42cb14b1 | 501 | } |
4b02108a | 502 | } |
42cb14b1 | 503 | local_irq_enable(); |
b20a3503 | 504 | |
78bd5209 | 505 | return MIGRATEPAGE_SUCCESS; |
b20a3503 | 506 | } |
3417013e | 507 | EXPORT_SYMBOL(folio_migrate_mapping); |
b20a3503 | 508 | |
290408d4 NH |
509 | /* |
510 | * The expected number of remaining references is the same as that | |
3417013e | 511 | * of folio_migrate_mapping(). |
290408d4 NH |
512 | */ |
513 | int migrate_huge_page_move_mapping(struct address_space *mapping, | |
b890ec2a | 514 | struct folio *dst, struct folio *src) |
290408d4 | 515 | { |
b890ec2a | 516 | XA_STATE(xas, &mapping->i_pages, folio_index(src)); |
290408d4 | 517 | int expected_count; |
290408d4 | 518 | |
89eb946a | 519 | xas_lock_irq(&xas); |
b890ec2a MWO |
520 | expected_count = 2 + folio_has_private(src); |
521 | if (!folio_ref_freeze(src, expected_count)) { | |
89eb946a | 522 | xas_unlock_irq(&xas); |
290408d4 NH |
523 | return -EAGAIN; |
524 | } | |
525 | ||
b890ec2a MWO |
526 | dst->index = src->index; |
527 | dst->mapping = src->mapping; | |
6a93ca8f | 528 | |
b890ec2a | 529 | folio_get(dst); |
290408d4 | 530 | |
b890ec2a | 531 | xas_store(&xas, dst); |
290408d4 | 532 | |
b890ec2a | 533 | folio_ref_unfreeze(src, expected_count - 1); |
290408d4 | 534 | |
89eb946a | 535 | xas_unlock_irq(&xas); |
6a93ca8f | 536 | |
78bd5209 | 537 | return MIGRATEPAGE_SUCCESS; |
290408d4 NH |
538 | } |
539 | ||
b20a3503 | 540 | /* |
19138349 | 541 | * Copy the flags and some other ancillary information |
b20a3503 | 542 | */ |
19138349 | 543 | void folio_migrate_flags(struct folio *newfolio, struct folio *folio) |
b20a3503 | 544 | { |
7851a45c RR |
545 | int cpupid; |
546 | ||
19138349 MWO |
547 | if (folio_test_error(folio)) |
548 | folio_set_error(newfolio); | |
549 | if (folio_test_referenced(folio)) | |
550 | folio_set_referenced(newfolio); | |
551 | if (folio_test_uptodate(folio)) | |
552 | folio_mark_uptodate(newfolio); | |
553 | if (folio_test_clear_active(folio)) { | |
554 | VM_BUG_ON_FOLIO(folio_test_unevictable(folio), folio); | |
555 | folio_set_active(newfolio); | |
556 | } else if (folio_test_clear_unevictable(folio)) | |
557 | folio_set_unevictable(newfolio); | |
558 | if (folio_test_workingset(folio)) | |
559 | folio_set_workingset(newfolio); | |
560 | if (folio_test_checked(folio)) | |
561 | folio_set_checked(newfolio); | |
6c287605 DH |
562 | /* |
563 | * PG_anon_exclusive (-> PG_mappedtodisk) is always migrated via | |
564 | * migration entries. We can still have PG_anon_exclusive set on an | |
565 | * effectively unmapped and unreferenced first sub-pages of an | |
566 | * anonymous THP: we can simply copy it here via PG_mappedtodisk. | |
567 | */ | |
19138349 MWO |
568 | if (folio_test_mappedtodisk(folio)) |
569 | folio_set_mappedtodisk(newfolio); | |
b20a3503 | 570 | |
3417013e | 571 | /* Move dirty on pages not done by folio_migrate_mapping() */ |
19138349 MWO |
572 | if (folio_test_dirty(folio)) |
573 | folio_set_dirty(newfolio); | |
b20a3503 | 574 | |
19138349 MWO |
575 | if (folio_test_young(folio)) |
576 | folio_set_young(newfolio); | |
577 | if (folio_test_idle(folio)) | |
578 | folio_set_idle(newfolio); | |
33c3fc71 | 579 | |
7851a45c RR |
580 | /* |
581 | * Copy NUMA information to the new page, to prevent over-eager | |
582 | * future migrations of this same page. | |
583 | */ | |
19138349 | 584 | cpupid = page_cpupid_xchg_last(&folio->page, -1); |
33024536 HY |
585 | /* |
586 | * For memory tiering mode, when migrate between slow and fast | |
587 | * memory node, reset cpupid, because that is used to record | |
588 | * page access time in slow memory node. | |
589 | */ | |
590 | if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) { | |
591 | bool f_toptier = node_is_toptier(page_to_nid(&folio->page)); | |
592 | bool t_toptier = node_is_toptier(page_to_nid(&newfolio->page)); | |
593 | ||
594 | if (f_toptier != t_toptier) | |
595 | cpupid = -1; | |
596 | } | |
19138349 | 597 | page_cpupid_xchg_last(&newfolio->page, cpupid); |
7851a45c | 598 | |
19138349 | 599 | folio_migrate_ksm(newfolio, folio); |
c8d6553b HD |
600 | /* |
601 | * Please do not reorder this without considering how mm/ksm.c's | |
602 | * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache(). | |
603 | */ | |
19138349 MWO |
604 | if (folio_test_swapcache(folio)) |
605 | folio_clear_swapcache(folio); | |
606 | folio_clear_private(folio); | |
ad2fa371 MS |
607 | |
608 | /* page->private contains hugetlb specific flags */ | |
19138349 MWO |
609 | if (!folio_test_hugetlb(folio)) |
610 | folio->private = NULL; | |
b20a3503 CL |
611 | |
612 | /* | |
613 | * If any waiters have accumulated on the new page then | |
614 | * wake them up. | |
615 | */ | |
19138349 MWO |
616 | if (folio_test_writeback(newfolio)) |
617 | folio_end_writeback(newfolio); | |
d435edca | 618 | |
6aeff241 YS |
619 | /* |
620 | * PG_readahead shares the same bit with PG_reclaim. The above | |
621 | * end_page_writeback() may clear PG_readahead mistakenly, so set the | |
622 | * bit after that. | |
623 | */ | |
19138349 MWO |
624 | if (folio_test_readahead(folio)) |
625 | folio_set_readahead(newfolio); | |
6aeff241 | 626 | |
19138349 | 627 | folio_copy_owner(newfolio, folio); |
74485cf2 | 628 | |
19138349 | 629 | if (!folio_test_hugetlb(folio)) |
d21bba2b | 630 | mem_cgroup_migrate(folio, newfolio); |
b20a3503 | 631 | } |
19138349 | 632 | EXPORT_SYMBOL(folio_migrate_flags); |
2916ecc0 | 633 | |
715cbfd6 | 634 | void folio_migrate_copy(struct folio *newfolio, struct folio *folio) |
2916ecc0 | 635 | { |
715cbfd6 MWO |
636 | folio_copy(newfolio, folio); |
637 | folio_migrate_flags(newfolio, folio); | |
2916ecc0 | 638 | } |
715cbfd6 | 639 | EXPORT_SYMBOL(folio_migrate_copy); |
b20a3503 | 640 | |
1d8b85cc CL |
641 | /************************************************************ |
642 | * Migration functions | |
643 | ***********************************************************/ | |
644 | ||
16ce101d AP |
645 | int migrate_folio_extra(struct address_space *mapping, struct folio *dst, |
646 | struct folio *src, enum migrate_mode mode, int extra_count) | |
647 | { | |
648 | int rc; | |
649 | ||
650 | BUG_ON(folio_test_writeback(src)); /* Writeback must be complete */ | |
651 | ||
652 | rc = folio_migrate_mapping(mapping, dst, src, extra_count); | |
653 | ||
654 | if (rc != MIGRATEPAGE_SUCCESS) | |
655 | return rc; | |
656 | ||
657 | if (mode != MIGRATE_SYNC_NO_COPY) | |
658 | folio_migrate_copy(dst, src); | |
659 | else | |
660 | folio_migrate_flags(dst, src); | |
661 | return MIGRATEPAGE_SUCCESS; | |
662 | } | |
663 | ||
54184650 MWO |
664 | /** |
665 | * migrate_folio() - Simple folio migration. | |
666 | * @mapping: The address_space containing the folio. | |
667 | * @dst: The folio to migrate the data to. | |
668 | * @src: The folio containing the current data. | |
669 | * @mode: How to migrate the page. | |
670 | * | |
671 | * Common logic to directly migrate a single LRU folio suitable for | |
672 | * folios that do not use PagePrivate/PagePrivate2. | |
b20a3503 | 673 | * |
54184650 | 674 | * Folios are locked upon entry and exit. |
b20a3503 | 675 | */ |
54184650 MWO |
676 | int migrate_folio(struct address_space *mapping, struct folio *dst, |
677 | struct folio *src, enum migrate_mode mode) | |
b20a3503 | 678 | { |
16ce101d | 679 | return migrate_folio_extra(mapping, dst, src, mode, 0); |
b20a3503 | 680 | } |
54184650 | 681 | EXPORT_SYMBOL(migrate_folio); |
b20a3503 | 682 | |
9361401e | 683 | #ifdef CONFIG_BLOCK |
84ade7c1 JK |
684 | /* Returns true if all buffers are successfully locked */ |
685 | static bool buffer_migrate_lock_buffers(struct buffer_head *head, | |
686 | enum migrate_mode mode) | |
687 | { | |
688 | struct buffer_head *bh = head; | |
4bb6dc79 | 689 | struct buffer_head *failed_bh; |
84ade7c1 | 690 | |
84ade7c1 | 691 | do { |
84ade7c1 | 692 | if (!trylock_buffer(bh)) { |
4bb6dc79 DA |
693 | if (mode == MIGRATE_ASYNC) |
694 | goto unlock; | |
695 | if (mode == MIGRATE_SYNC_LIGHT && !buffer_uptodate(bh)) | |
696 | goto unlock; | |
697 | lock_buffer(bh); | |
84ade7c1 JK |
698 | } |
699 | ||
700 | bh = bh->b_this_page; | |
701 | } while (bh != head); | |
4bb6dc79 | 702 | |
84ade7c1 | 703 | return true; |
4bb6dc79 DA |
704 | |
705 | unlock: | |
706 | /* We failed to lock the buffer and cannot stall. */ | |
707 | failed_bh = bh; | |
708 | bh = head; | |
709 | while (bh != failed_bh) { | |
710 | unlock_buffer(bh); | |
711 | bh = bh->b_this_page; | |
712 | } | |
713 | ||
714 | return false; | |
84ade7c1 JK |
715 | } |
716 | ||
67235182 MWO |
717 | static int __buffer_migrate_folio(struct address_space *mapping, |
718 | struct folio *dst, struct folio *src, enum migrate_mode mode, | |
89cb0888 | 719 | bool check_refs) |
1d8b85cc | 720 | { |
1d8b85cc CL |
721 | struct buffer_head *bh, *head; |
722 | int rc; | |
cc4f11e6 | 723 | int expected_count; |
1d8b85cc | 724 | |
67235182 MWO |
725 | head = folio_buffers(src); |
726 | if (!head) | |
54184650 | 727 | return migrate_folio(mapping, dst, src, mode); |
1d8b85cc | 728 | |
cc4f11e6 | 729 | /* Check whether page does not have extra refs before we do more work */ |
108ca835 | 730 | expected_count = folio_expected_refs(mapping, src); |
67235182 | 731 | if (folio_ref_count(src) != expected_count) |
cc4f11e6 | 732 | return -EAGAIN; |
1d8b85cc | 733 | |
cc4f11e6 JK |
734 | if (!buffer_migrate_lock_buffers(head, mode)) |
735 | return -EAGAIN; | |
1d8b85cc | 736 | |
89cb0888 JK |
737 | if (check_refs) { |
738 | bool busy; | |
739 | bool invalidated = false; | |
740 | ||
741 | recheck_buffers: | |
742 | busy = false; | |
743 | spin_lock(&mapping->private_lock); | |
744 | bh = head; | |
745 | do { | |
746 | if (atomic_read(&bh->b_count)) { | |
747 | busy = true; | |
748 | break; | |
749 | } | |
750 | bh = bh->b_this_page; | |
751 | } while (bh != head); | |
89cb0888 JK |
752 | if (busy) { |
753 | if (invalidated) { | |
754 | rc = -EAGAIN; | |
755 | goto unlock_buffers; | |
756 | } | |
ebdf4de5 | 757 | spin_unlock(&mapping->private_lock); |
89cb0888 JK |
758 | invalidate_bh_lrus(); |
759 | invalidated = true; | |
760 | goto recheck_buffers; | |
761 | } | |
762 | } | |
763 | ||
67235182 | 764 | rc = folio_migrate_mapping(mapping, dst, src, 0); |
78bd5209 | 765 | if (rc != MIGRATEPAGE_SUCCESS) |
cc4f11e6 | 766 | goto unlock_buffers; |
1d8b85cc | 767 | |
67235182 | 768 | folio_attach_private(dst, folio_detach_private(src)); |
1d8b85cc CL |
769 | |
770 | bh = head; | |
771 | do { | |
67235182 | 772 | set_bh_page(bh, &dst->page, bh_offset(bh)); |
1d8b85cc | 773 | bh = bh->b_this_page; |
1d8b85cc CL |
774 | } while (bh != head); |
775 | ||
2916ecc0 | 776 | if (mode != MIGRATE_SYNC_NO_COPY) |
67235182 | 777 | folio_migrate_copy(dst, src); |
2916ecc0 | 778 | else |
67235182 | 779 | folio_migrate_flags(dst, src); |
1d8b85cc | 780 | |
cc4f11e6 JK |
781 | rc = MIGRATEPAGE_SUCCESS; |
782 | unlock_buffers: | |
ebdf4de5 JK |
783 | if (check_refs) |
784 | spin_unlock(&mapping->private_lock); | |
1d8b85cc CL |
785 | bh = head; |
786 | do { | |
787 | unlock_buffer(bh); | |
1d8b85cc | 788 | bh = bh->b_this_page; |
1d8b85cc CL |
789 | } while (bh != head); |
790 | ||
cc4f11e6 | 791 | return rc; |
1d8b85cc | 792 | } |
89cb0888 | 793 | |
67235182 MWO |
794 | /** |
795 | * buffer_migrate_folio() - Migration function for folios with buffers. | |
796 | * @mapping: The address space containing @src. | |
797 | * @dst: The folio to migrate to. | |
798 | * @src: The folio to migrate from. | |
799 | * @mode: How to migrate the folio. | |
800 | * | |
801 | * This function can only be used if the underlying filesystem guarantees | |
802 | * that no other references to @src exist. For example attached buffer | |
803 | * heads are accessed only under the folio lock. If your filesystem cannot | |
804 | * provide this guarantee, buffer_migrate_folio_norefs() may be more | |
805 | * appropriate. | |
806 | * | |
807 | * Return: 0 on success or a negative errno on failure. | |
89cb0888 | 808 | */ |
67235182 MWO |
809 | int buffer_migrate_folio(struct address_space *mapping, |
810 | struct folio *dst, struct folio *src, enum migrate_mode mode) | |
89cb0888 | 811 | { |
67235182 | 812 | return __buffer_migrate_folio(mapping, dst, src, mode, false); |
89cb0888 | 813 | } |
67235182 MWO |
814 | EXPORT_SYMBOL(buffer_migrate_folio); |
815 | ||
816 | /** | |
817 | * buffer_migrate_folio_norefs() - Migration function for folios with buffers. | |
818 | * @mapping: The address space containing @src. | |
819 | * @dst: The folio to migrate to. | |
820 | * @src: The folio to migrate from. | |
821 | * @mode: How to migrate the folio. | |
822 | * | |
823 | * Like buffer_migrate_folio() except that this variant is more careful | |
824 | * and checks that there are also no buffer head references. This function | |
825 | * is the right one for mappings where buffer heads are directly looked | |
826 | * up and referenced (such as block device mappings). | |
827 | * | |
828 | * Return: 0 on success or a negative errno on failure. | |
89cb0888 | 829 | */ |
67235182 MWO |
830 | int buffer_migrate_folio_norefs(struct address_space *mapping, |
831 | struct folio *dst, struct folio *src, enum migrate_mode mode) | |
89cb0888 | 832 | { |
67235182 | 833 | return __buffer_migrate_folio(mapping, dst, src, mode, true); |
89cb0888 | 834 | } |
e26355e2 | 835 | EXPORT_SYMBOL_GPL(buffer_migrate_folio_norefs); |
9361401e | 836 | #endif |
1d8b85cc | 837 | |
2ec810d5 MWO |
838 | int filemap_migrate_folio(struct address_space *mapping, |
839 | struct folio *dst, struct folio *src, enum migrate_mode mode) | |
840 | { | |
841 | int ret; | |
842 | ||
843 | ret = folio_migrate_mapping(mapping, dst, src, 0); | |
844 | if (ret != MIGRATEPAGE_SUCCESS) | |
845 | return ret; | |
846 | ||
847 | if (folio_get_private(src)) | |
848 | folio_attach_private(dst, folio_detach_private(src)); | |
849 | ||
850 | if (mode != MIGRATE_SYNC_NO_COPY) | |
851 | folio_migrate_copy(dst, src); | |
852 | else | |
853 | folio_migrate_flags(dst, src); | |
854 | return MIGRATEPAGE_SUCCESS; | |
855 | } | |
856 | EXPORT_SYMBOL_GPL(filemap_migrate_folio); | |
857 | ||
04e62a29 | 858 | /* |
2be7fa10 | 859 | * Writeback a folio to clean the dirty state |
04e62a29 | 860 | */ |
2be7fa10 | 861 | static int writeout(struct address_space *mapping, struct folio *folio) |
8351a6e4 | 862 | { |
04e62a29 CL |
863 | struct writeback_control wbc = { |
864 | .sync_mode = WB_SYNC_NONE, | |
865 | .nr_to_write = 1, | |
866 | .range_start = 0, | |
867 | .range_end = LLONG_MAX, | |
04e62a29 CL |
868 | .for_reclaim = 1 |
869 | }; | |
870 | int rc; | |
871 | ||
872 | if (!mapping->a_ops->writepage) | |
873 | /* No write method for the address space */ | |
874 | return -EINVAL; | |
875 | ||
2be7fa10 | 876 | if (!folio_clear_dirty_for_io(folio)) |
04e62a29 CL |
877 | /* Someone else already triggered a write */ |
878 | return -EAGAIN; | |
879 | ||
8351a6e4 | 880 | /* |
2be7fa10 MWO |
881 | * A dirty folio may imply that the underlying filesystem has |
882 | * the folio on some queue. So the folio must be clean for | |
883 | * migration. Writeout may mean we lose the lock and the | |
884 | * folio state is no longer what we checked for earlier. | |
04e62a29 CL |
885 | * At this point we know that the migration attempt cannot |
886 | * be successful. | |
8351a6e4 | 887 | */ |
4eecb8b9 | 888 | remove_migration_ptes(folio, folio, false); |
8351a6e4 | 889 | |
2be7fa10 | 890 | rc = mapping->a_ops->writepage(&folio->page, &wbc); |
8351a6e4 | 891 | |
04e62a29 CL |
892 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
893 | /* unlocked. Relock */ | |
2be7fa10 | 894 | folio_lock(folio); |
04e62a29 | 895 | |
bda8550d | 896 | return (rc < 0) ? -EIO : -EAGAIN; |
04e62a29 CL |
897 | } |
898 | ||
899 | /* | |
900 | * Default handling if a filesystem does not provide a migration function. | |
901 | */ | |
8faa8ef5 MWO |
902 | static int fallback_migrate_folio(struct address_space *mapping, |
903 | struct folio *dst, struct folio *src, enum migrate_mode mode) | |
04e62a29 | 904 | { |
8faa8ef5 MWO |
905 | if (folio_test_dirty(src)) { |
906 | /* Only writeback folios in full synchronous migration */ | |
2916ecc0 JG |
907 | switch (mode) { |
908 | case MIGRATE_SYNC: | |
909 | case MIGRATE_SYNC_NO_COPY: | |
910 | break; | |
911 | default: | |
b969c4ab | 912 | return -EBUSY; |
2916ecc0 | 913 | } |
2be7fa10 | 914 | return writeout(mapping, src); |
b969c4ab | 915 | } |
8351a6e4 CL |
916 | |
917 | /* | |
918 | * Buffers may be managed in a filesystem specific way. | |
919 | * We must have no buffers or drop them. | |
920 | */ | |
8faa8ef5 MWO |
921 | if (folio_test_private(src) && |
922 | !filemap_release_folio(src, GFP_KERNEL)) | |
806031bb | 923 | return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY; |
8351a6e4 | 924 | |
54184650 | 925 | return migrate_folio(mapping, dst, src, mode); |
8351a6e4 CL |
926 | } |
927 | ||
e24f0b8f CL |
928 | /* |
929 | * Move a page to a newly allocated page | |
930 | * The page is locked and all ptes have been successfully removed. | |
931 | * | |
932 | * The new page will have replaced the old page if this function | |
933 | * is successful. | |
894bc310 LS |
934 | * |
935 | * Return value: | |
936 | * < 0 - error code | |
78bd5209 | 937 | * MIGRATEPAGE_SUCCESS - success |
e24f0b8f | 938 | */ |
e7e3ffeb | 939 | static int move_to_new_folio(struct folio *dst, struct folio *src, |
5c3f9a67 | 940 | enum migrate_mode mode) |
e24f0b8f | 941 | { |
bda807d4 | 942 | int rc = -EAGAIN; |
e7e3ffeb | 943 | bool is_lru = !__PageMovable(&src->page); |
e24f0b8f | 944 | |
e7e3ffeb MWO |
945 | VM_BUG_ON_FOLIO(!folio_test_locked(src), src); |
946 | VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst); | |
e24f0b8f | 947 | |
bda807d4 | 948 | if (likely(is_lru)) { |
68f2736a MWO |
949 | struct address_space *mapping = folio_mapping(src); |
950 | ||
bda807d4 | 951 | if (!mapping) |
54184650 | 952 | rc = migrate_folio(mapping, dst, src, mode); |
5490da4f | 953 | else if (mapping->a_ops->migrate_folio) |
bda807d4 | 954 | /* |
5490da4f MWO |
955 | * Most folios have a mapping and most filesystems |
956 | * provide a migrate_folio callback. Anonymous folios | |
bda807d4 | 957 | * are part of swap space which also has its own |
5490da4f | 958 | * migrate_folio callback. This is the most common path |
bda807d4 MK |
959 | * for page migration. |
960 | */ | |
5490da4f MWO |
961 | rc = mapping->a_ops->migrate_folio(mapping, dst, src, |
962 | mode); | |
bda807d4 | 963 | else |
8faa8ef5 | 964 | rc = fallback_migrate_folio(mapping, dst, src, mode); |
bda807d4 | 965 | } else { |
68f2736a MWO |
966 | const struct movable_operations *mops; |
967 | ||
e24f0b8f | 968 | /* |
bda807d4 MK |
969 | * In case of non-lru page, it could be released after |
970 | * isolation step. In that case, we shouldn't try migration. | |
e24f0b8f | 971 | */ |
e7e3ffeb MWO |
972 | VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); |
973 | if (!folio_test_movable(src)) { | |
bda807d4 | 974 | rc = MIGRATEPAGE_SUCCESS; |
e7e3ffeb | 975 | folio_clear_isolated(src); |
bda807d4 MK |
976 | goto out; |
977 | } | |
978 | ||
da707a6d | 979 | mops = folio_movable_ops(src); |
68f2736a | 980 | rc = mops->migrate_page(&dst->page, &src->page, mode); |
bda807d4 | 981 | WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS && |
e7e3ffeb | 982 | !folio_test_isolated(src)); |
bda807d4 | 983 | } |
e24f0b8f | 984 | |
5c3f9a67 | 985 | /* |
e7e3ffeb MWO |
986 | * When successful, old pagecache src->mapping must be cleared before |
987 | * src is freed; but stats require that PageAnon be left as PageAnon. | |
5c3f9a67 HD |
988 | */ |
989 | if (rc == MIGRATEPAGE_SUCCESS) { | |
e7e3ffeb MWO |
990 | if (__PageMovable(&src->page)) { |
991 | VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); | |
bda807d4 MK |
992 | |
993 | /* | |
994 | * We clear PG_movable under page_lock so any compactor | |
995 | * cannot try to migrate this page. | |
996 | */ | |
e7e3ffeb | 997 | folio_clear_isolated(src); |
bda807d4 MK |
998 | } |
999 | ||
1000 | /* | |
e7e3ffeb | 1001 | * Anonymous and movable src->mapping will be cleared by |
bda807d4 MK |
1002 | * free_pages_prepare so don't reset it here for keeping |
1003 | * the type to work PageAnon, for example. | |
1004 | */ | |
e7e3ffeb MWO |
1005 | if (!folio_mapping_flags(src)) |
1006 | src->mapping = NULL; | |
d2b2c6dd | 1007 | |
e7e3ffeb MWO |
1008 | if (likely(!folio_is_zone_device(dst))) |
1009 | flush_dcache_folio(dst); | |
3fe2011f | 1010 | } |
bda807d4 | 1011 | out: |
e24f0b8f CL |
1012 | return rc; |
1013 | } | |
1014 | ||
64c8902e HY |
1015 | /* |
1016 | * To record some information during migration, we use some unused | |
1017 | * fields (mapping and private) of struct folio of the newly allocated | |
1018 | * destination folio. This is safe because nobody is using them | |
1019 | * except us. | |
1020 | */ | |
e77d587a LT |
1021 | union migration_ptr { |
1022 | struct anon_vma *anon_vma; | |
1023 | struct address_space *mapping; | |
1024 | }; | |
64c8902e HY |
1025 | static void __migrate_folio_record(struct folio *dst, |
1026 | unsigned long page_was_mapped, | |
1027 | struct anon_vma *anon_vma) | |
1028 | { | |
e77d587a LT |
1029 | union migration_ptr ptr = { .anon_vma = anon_vma }; |
1030 | dst->mapping = ptr.mapping; | |
64c8902e HY |
1031 | dst->private = (void *)page_was_mapped; |
1032 | } | |
1033 | ||
1034 | static void __migrate_folio_extract(struct folio *dst, | |
1035 | int *page_was_mappedp, | |
1036 | struct anon_vma **anon_vmap) | |
1037 | { | |
e77d587a LT |
1038 | union migration_ptr ptr = { .mapping = dst->mapping }; |
1039 | *anon_vmap = ptr.anon_vma; | |
64c8902e HY |
1040 | *page_was_mappedp = (unsigned long)dst->private; |
1041 | dst->mapping = NULL; | |
1042 | dst->private = NULL; | |
1043 | } | |
1044 | ||
5dfab109 HY |
1045 | /* Restore the source folio to the original state upon failure */ |
1046 | static void migrate_folio_undo_src(struct folio *src, | |
1047 | int page_was_mapped, | |
1048 | struct anon_vma *anon_vma, | |
ebe75e47 | 1049 | bool locked, |
5dfab109 HY |
1050 | struct list_head *ret) |
1051 | { | |
1052 | if (page_was_mapped) | |
1053 | remove_migration_ptes(src, src, false); | |
1054 | /* Drop an anon_vma reference if we took one */ | |
1055 | if (anon_vma) | |
1056 | put_anon_vma(anon_vma); | |
ebe75e47 HY |
1057 | if (locked) |
1058 | folio_unlock(src); | |
1059 | if (ret) | |
1060 | list_move_tail(&src->lru, ret); | |
5dfab109 HY |
1061 | } |
1062 | ||
1063 | /* Restore the destination folio to the original state upon failure */ | |
4e096ae1 MWO |
1064 | static void migrate_folio_undo_dst(struct folio *dst, bool locked, |
1065 | free_folio_t put_new_folio, unsigned long private) | |
5dfab109 | 1066 | { |
ebe75e47 HY |
1067 | if (locked) |
1068 | folio_unlock(dst); | |
4e096ae1 MWO |
1069 | if (put_new_folio) |
1070 | put_new_folio(dst, private); | |
5dfab109 HY |
1071 | else |
1072 | folio_put(dst); | |
1073 | } | |
1074 | ||
64c8902e HY |
1075 | /* Cleanup src folio upon migration success */ |
1076 | static void migrate_folio_done(struct folio *src, | |
1077 | enum migrate_reason reason) | |
1078 | { | |
1079 | /* | |
1080 | * Compaction can migrate also non-LRU pages which are | |
1081 | * not accounted to NR_ISOLATED_*. They can be recognized | |
1082 | * as __PageMovable | |
1083 | */ | |
1084 | if (likely(!__folio_test_movable(src))) | |
1085 | mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + | |
1086 | folio_is_file_lru(src), -folio_nr_pages(src)); | |
1087 | ||
1088 | if (reason != MR_MEMORY_FAILURE) | |
1089 | /* We release the page in page_handle_poison. */ | |
1090 | folio_put(src); | |
1091 | } | |
1092 | ||
ebe75e47 | 1093 | /* Obtain the lock on page, remove all ptes. */ |
4e096ae1 MWO |
1094 | static int migrate_folio_unmap(new_folio_t get_new_folio, |
1095 | free_folio_t put_new_folio, unsigned long private, | |
1096 | struct folio *src, struct folio **dstp, enum migrate_mode mode, | |
1097 | enum migrate_reason reason, struct list_head *ret) | |
e24f0b8f | 1098 | { |
ebe75e47 | 1099 | struct folio *dst; |
0dabec93 | 1100 | int rc = -EAGAIN; |
64c8902e | 1101 | int page_was_mapped = 0; |
3f6c8272 | 1102 | struct anon_vma *anon_vma = NULL; |
682a71a1 | 1103 | bool is_lru = !__PageMovable(&src->page); |
ebe75e47 HY |
1104 | bool locked = false; |
1105 | bool dst_locked = false; | |
1106 | ||
ebe75e47 HY |
1107 | if (folio_ref_count(src) == 1) { |
1108 | /* Folio was freed from under us. So we are done. */ | |
1109 | folio_clear_active(src); | |
1110 | folio_clear_unevictable(src); | |
1111 | /* free_pages_prepare() will clear PG_isolated. */ | |
1112 | list_del(&src->lru); | |
1113 | migrate_folio_done(src, reason); | |
1114 | return MIGRATEPAGE_SUCCESS; | |
1115 | } | |
1116 | ||
4e096ae1 MWO |
1117 | dst = get_new_folio(src, private); |
1118 | if (!dst) | |
ebe75e47 | 1119 | return -ENOMEM; |
ebe75e47 HY |
1120 | *dstp = dst; |
1121 | ||
1122 | dst->private = NULL; | |
95a402c3 | 1123 | |
682a71a1 | 1124 | if (!folio_trylock(src)) { |
2ef7dbb2 | 1125 | if (mode == MIGRATE_ASYNC) |
0dabec93 | 1126 | goto out; |
3e7d3449 MG |
1127 | |
1128 | /* | |
1129 | * It's not safe for direct compaction to call lock_page. | |
1130 | * For example, during page readahead pages are added locked | |
1131 | * to the LRU. Later, when the IO completes the pages are | |
1132 | * marked uptodate and unlocked. However, the queueing | |
1133 | * could be merging multiple pages for one bio (e.g. | |
d4388340 | 1134 | * mpage_readahead). If an allocation happens for the |
3e7d3449 MG |
1135 | * second or third page, the process can end up locking |
1136 | * the same page twice and deadlocking. Rather than | |
1137 | * trying to be clever about what pages can be locked, | |
1138 | * avoid the use of lock_page for direct compaction | |
1139 | * altogether. | |
1140 | */ | |
1141 | if (current->flags & PF_MEMALLOC) | |
0dabec93 | 1142 | goto out; |
3e7d3449 | 1143 | |
4bb6dc79 DA |
1144 | /* |
1145 | * In "light" mode, we can wait for transient locks (eg | |
1146 | * inserting a page into the page table), but it's not | |
1147 | * worth waiting for I/O. | |
1148 | */ | |
1149 | if (mode == MIGRATE_SYNC_LIGHT && !folio_test_uptodate(src)) | |
1150 | goto out; | |
1151 | ||
682a71a1 | 1152 | folio_lock(src); |
e24f0b8f | 1153 | } |
ebe75e47 | 1154 | locked = true; |
e24f0b8f | 1155 | |
682a71a1 | 1156 | if (folio_test_writeback(src)) { |
11bc82d6 | 1157 | /* |
fed5b64a | 1158 | * Only in the case of a full synchronous migration is it |
a6bc32b8 MG |
1159 | * necessary to wait for PageWriteback. In the async case, |
1160 | * the retry loop is too short and in the sync-light case, | |
1161 | * the overhead of stalling is too much | |
11bc82d6 | 1162 | */ |
2916ecc0 JG |
1163 | switch (mode) { |
1164 | case MIGRATE_SYNC: | |
1165 | case MIGRATE_SYNC_NO_COPY: | |
1166 | break; | |
1167 | default: | |
11bc82d6 | 1168 | rc = -EBUSY; |
ebe75e47 | 1169 | goto out; |
11bc82d6 | 1170 | } |
682a71a1 | 1171 | folio_wait_writeback(src); |
e24f0b8f | 1172 | } |
03f15c86 | 1173 | |
e24f0b8f | 1174 | /* |
682a71a1 MWO |
1175 | * By try_to_migrate(), src->mapcount goes down to 0 here. In this case, |
1176 | * we cannot notice that anon_vma is freed while we migrate a page. | |
1ce82b69 | 1177 | * This get_anon_vma() delays freeing anon_vma pointer until the end |
dc386d4d | 1178 | * of migration. File cache pages are no problem because of page_lock() |
989f89c5 KH |
1179 | * File Caches may use write_page() or lock_page() in migration, then, |
1180 | * just care Anon page here. | |
03f15c86 | 1181 | * |
29eea9b5 | 1182 | * Only folio_get_anon_vma() understands the subtleties of |
03f15c86 HD |
1183 | * getting a hold on an anon_vma from outside one of its mms. |
1184 | * But if we cannot get anon_vma, then we won't need it anyway, | |
1185 | * because that implies that the anon page is no longer mapped | |
1186 | * (and cannot be remapped so long as we hold the page lock). | |
dc386d4d | 1187 | */ |
682a71a1 | 1188 | if (folio_test_anon(src) && !folio_test_ksm(src)) |
29eea9b5 | 1189 | anon_vma = folio_get_anon_vma(src); |
62e1c553 | 1190 | |
7db7671f HD |
1191 | /* |
1192 | * Block others from accessing the new page when we get around to | |
1193 | * establishing additional references. We are usually the only one | |
682a71a1 MWO |
1194 | * holding a reference to dst at this point. We used to have a BUG |
1195 | * here if folio_trylock(dst) fails, but would like to allow for | |
1196 | * cases where there might be a race with the previous use of dst. | |
7db7671f HD |
1197 | * This is much like races on refcount of oldpage: just don't BUG(). |
1198 | */ | |
682a71a1 | 1199 | if (unlikely(!folio_trylock(dst))) |
ebe75e47 HY |
1200 | goto out; |
1201 | dst_locked = true; | |
7db7671f | 1202 | |
bda807d4 | 1203 | if (unlikely(!is_lru)) { |
64c8902e HY |
1204 | __migrate_folio_record(dst, page_was_mapped, anon_vma); |
1205 | return MIGRATEPAGE_UNMAP; | |
bda807d4 MK |
1206 | } |
1207 | ||
dc386d4d | 1208 | /* |
62e1c553 SL |
1209 | * Corner case handling: |
1210 | * 1. When a new swap-cache page is read into, it is added to the LRU | |
1211 | * and treated as swapcache but it has no rmap yet. | |
682a71a1 | 1212 | * Calling try_to_unmap() against a src->mapping==NULL page will |
62e1c553 | 1213 | * trigger a BUG. So handle it here. |
d12b8951 | 1214 | * 2. An orphaned page (see truncate_cleanup_page) might have |
62e1c553 SL |
1215 | * fs-private metadata. The page can be picked up due to memory |
1216 | * offlining. Everywhere else except page reclaim, the page is | |
1217 | * invisible to the vm, so the page can not be migrated. So try to | |
1218 | * free the metadata, so the page can be freed. | |
e24f0b8f | 1219 | */ |
682a71a1 MWO |
1220 | if (!src->mapping) { |
1221 | if (folio_test_private(src)) { | |
1222 | try_to_free_buffers(src); | |
ebe75e47 | 1223 | goto out; |
62e1c553 | 1224 | } |
682a71a1 | 1225 | } else if (folio_mapped(src)) { |
7db7671f | 1226 | /* Establish migration ptes */ |
682a71a1 MWO |
1227 | VM_BUG_ON_FOLIO(folio_test_anon(src) && |
1228 | !folio_test_ksm(src) && !anon_vma, src); | |
fb3592c4 | 1229 | try_to_migrate(src, mode == MIGRATE_ASYNC ? TTU_BATCH_FLUSH : 0); |
64c8902e | 1230 | page_was_mapped = 1; |
2ebba6b7 | 1231 | } |
dc386d4d | 1232 | |
64c8902e HY |
1233 | if (!folio_mapped(src)) { |
1234 | __migrate_folio_record(dst, page_was_mapped, anon_vma); | |
1235 | return MIGRATEPAGE_UNMAP; | |
1236 | } | |
1237 | ||
64c8902e | 1238 | out: |
80562ba0 HY |
1239 | /* |
1240 | * A folio that has not been unmapped will be restored to | |
1241 | * right list unless we want to retry. | |
1242 | */ | |
fb3592c4 | 1243 | if (rc == -EAGAIN) |
ebe75e47 | 1244 | ret = NULL; |
80562ba0 | 1245 | |
ebe75e47 | 1246 | migrate_folio_undo_src(src, page_was_mapped, anon_vma, locked, ret); |
4e096ae1 | 1247 | migrate_folio_undo_dst(dst, dst_locked, put_new_folio, private); |
80562ba0 HY |
1248 | |
1249 | return rc; | |
1250 | } | |
1251 | ||
ebe75e47 | 1252 | /* Migrate the folio to the newly allocated folio in dst. */ |
4e096ae1 | 1253 | static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private, |
ebe75e47 HY |
1254 | struct folio *src, struct folio *dst, |
1255 | enum migrate_mode mode, enum migrate_reason reason, | |
1256 | struct list_head *ret) | |
64c8902e HY |
1257 | { |
1258 | int rc; | |
1259 | int page_was_mapped = 0; | |
1260 | struct anon_vma *anon_vma = NULL; | |
1261 | bool is_lru = !__PageMovable(&src->page); | |
5dfab109 | 1262 | struct list_head *prev; |
64c8902e HY |
1263 | |
1264 | __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); | |
5dfab109 HY |
1265 | prev = dst->lru.prev; |
1266 | list_del(&dst->lru); | |
64c8902e HY |
1267 | |
1268 | rc = move_to_new_folio(dst, src, mode); | |
ebe75e47 HY |
1269 | if (rc) |
1270 | goto out; | |
5dfab109 | 1271 | |
64c8902e HY |
1272 | if (unlikely(!is_lru)) |
1273 | goto out_unlock_both; | |
e24f0b8f | 1274 | |
c3096e67 | 1275 | /* |
682a71a1 | 1276 | * When successful, push dst to LRU immediately: so that if it |
c3096e67 | 1277 | * turns out to be an mlocked page, remove_migration_ptes() will |
682a71a1 | 1278 | * automatically build up the correct dst->mlock_count for it. |
c3096e67 HD |
1279 | * |
1280 | * We would like to do something similar for the old page, when | |
1281 | * unsuccessful, and other cases when a page has been temporarily | |
1282 | * isolated from the unevictable LRU: but this case is the easiest. | |
1283 | */ | |
ebe75e47 HY |
1284 | folio_add_lru(dst); |
1285 | if (page_was_mapped) | |
1286 | lru_add_drain(); | |
c3096e67 | 1287 | |
5c3f9a67 | 1288 | if (page_was_mapped) |
ebe75e47 | 1289 | remove_migration_ptes(src, dst, false); |
3f6c8272 | 1290 | |
7db7671f | 1291 | out_unlock_both: |
682a71a1 | 1292 | folio_unlock(dst); |
ebe75e47 | 1293 | set_page_owner_migrate_reason(&dst->page, reason); |
c6c919eb | 1294 | /* |
682a71a1 | 1295 | * If migration is successful, decrease refcount of dst, |
c6c919eb | 1296 | * which will not free the page because new page owner increased |
c3096e67 | 1297 | * refcounter. |
c6c919eb | 1298 | */ |
ebe75e47 | 1299 | folio_put(dst); |
c6c919eb | 1300 | |
dd4ae78a | 1301 | /* |
ebe75e47 HY |
1302 | * A folio that has been migrated has all references removed |
1303 | * and will be freed. | |
dd4ae78a | 1304 | */ |
ebe75e47 HY |
1305 | list_del(&src->lru); |
1306 | /* Drop an anon_vma reference if we took one */ | |
1307 | if (anon_vma) | |
1308 | put_anon_vma(anon_vma); | |
1309 | folio_unlock(src); | |
1310 | migrate_folio_done(src, reason); | |
bf6bddf1 | 1311 | |
ebe75e47 | 1312 | return rc; |
0dabec93 | 1313 | out: |
dd4ae78a | 1314 | /* |
ebe75e47 HY |
1315 | * A folio that has not been migrated will be restored to |
1316 | * right list unless we want to retry. | |
dd4ae78a | 1317 | */ |
ebe75e47 HY |
1318 | if (rc == -EAGAIN) { |
1319 | list_add(&dst->lru, prev); | |
1320 | __migrate_folio_record(dst, page_was_mapped, anon_vma); | |
1321 | return rc; | |
e24f0b8f | 1322 | } |
68711a74 | 1323 | |
ebe75e47 | 1324 | migrate_folio_undo_src(src, page_was_mapped, anon_vma, true, ret); |
4e096ae1 | 1325 | migrate_folio_undo_dst(dst, true, put_new_folio, private); |
ebe75e47 | 1326 | |
e24f0b8f CL |
1327 | return rc; |
1328 | } | |
1329 | ||
290408d4 NH |
1330 | /* |
1331 | * Counterpart of unmap_and_move_page() for hugepage migration. | |
1332 | * | |
1333 | * This function doesn't wait the completion of hugepage I/O | |
1334 | * because there is no race between I/O and migration for hugepage. | |
1335 | * Note that currently hugepage I/O occurs only in direct I/O | |
1336 | * where no lock is held and PG_writeback is irrelevant, | |
1337 | * and writeback status of all subpages are counted in the reference | |
1338 | * count of the head page (i.e. if all subpages of a 2MB hugepage are | |
1339 | * under direct I/O, the reference of the head page is 512 and a bit more.) | |
1340 | * This means that when we try to migrate hugepage whose subpages are | |
1341 | * doing direct I/O, some references remain after try_to_unmap() and | |
1342 | * hugepage migration fails without data corruption. | |
1343 | * | |
1344 | * There is also no race when direct I/O is issued on the page under migration, | |
1345 | * because then pte is replaced with migration swap entry and direct I/O code | |
1346 | * will wait in the page fault for migration to complete. | |
1347 | */ | |
4e096ae1 MWO |
1348 | static int unmap_and_move_huge_page(new_folio_t get_new_folio, |
1349 | free_folio_t put_new_folio, unsigned long private, | |
1350 | struct folio *src, int force, enum migrate_mode mode, | |
1351 | int reason, struct list_head *ret) | |
290408d4 | 1352 | { |
4e096ae1 | 1353 | struct folio *dst; |
2def7424 | 1354 | int rc = -EAGAIN; |
2ebba6b7 | 1355 | int page_was_mapped = 0; |
290408d4 | 1356 | struct anon_vma *anon_vma = NULL; |
c0d0381a | 1357 | struct address_space *mapping = NULL; |
290408d4 | 1358 | |
c33db292 | 1359 | if (folio_ref_count(src) == 1) { |
71a64f61 | 1360 | /* page was freed from under us. So we are done. */ |
ea8e72f4 | 1361 | folio_putback_active_hugetlb(src); |
71a64f61 MS |
1362 | return MIGRATEPAGE_SUCCESS; |
1363 | } | |
1364 | ||
4e096ae1 MWO |
1365 | dst = get_new_folio(src, private); |
1366 | if (!dst) | |
290408d4 NH |
1367 | return -ENOMEM; |
1368 | ||
c33db292 | 1369 | if (!folio_trylock(src)) { |
2916ecc0 | 1370 | if (!force) |
290408d4 | 1371 | goto out; |
2916ecc0 JG |
1372 | switch (mode) { |
1373 | case MIGRATE_SYNC: | |
1374 | case MIGRATE_SYNC_NO_COPY: | |
1375 | break; | |
1376 | default: | |
1377 | goto out; | |
1378 | } | |
c33db292 | 1379 | folio_lock(src); |
290408d4 NH |
1380 | } |
1381 | ||
cb6acd01 MK |
1382 | /* |
1383 | * Check for pages which are in the process of being freed. Without | |
c33db292 | 1384 | * folio_mapping() set, hugetlbfs specific move page routine will not |
cb6acd01 MK |
1385 | * be called and we could leak usage counts for subpools. |
1386 | */ | |
345c62d1 | 1387 | if (hugetlb_folio_subpool(src) && !folio_mapping(src)) { |
cb6acd01 MK |
1388 | rc = -EBUSY; |
1389 | goto out_unlock; | |
1390 | } | |
1391 | ||
c33db292 | 1392 | if (folio_test_anon(src)) |
29eea9b5 | 1393 | anon_vma = folio_get_anon_vma(src); |
290408d4 | 1394 | |
c33db292 | 1395 | if (unlikely(!folio_trylock(dst))) |
7db7671f HD |
1396 | goto put_anon; |
1397 | ||
c33db292 | 1398 | if (folio_mapped(src)) { |
a98a2f0c | 1399 | enum ttu_flags ttu = 0; |
336bf30e | 1400 | |
c33db292 | 1401 | if (!folio_test_anon(src)) { |
336bf30e MK |
1402 | /* |
1403 | * In shared mappings, try_to_unmap could potentially | |
1404 | * call huge_pmd_unshare. Because of this, take | |
1405 | * semaphore in write mode here and set TTU_RMAP_LOCKED | |
1406 | * to let lower levels know we have taken the lock. | |
1407 | */ | |
4e096ae1 | 1408 | mapping = hugetlb_page_mapping_lock_write(&src->page); |
336bf30e MK |
1409 | if (unlikely(!mapping)) |
1410 | goto unlock_put_anon; | |
1411 | ||
5202978b | 1412 | ttu = TTU_RMAP_LOCKED; |
336bf30e | 1413 | } |
c0d0381a | 1414 | |
4b8554c5 | 1415 | try_to_migrate(src, ttu); |
2ebba6b7 | 1416 | page_was_mapped = 1; |
336bf30e | 1417 | |
5202978b | 1418 | if (ttu & TTU_RMAP_LOCKED) |
336bf30e | 1419 | i_mmap_unlock_write(mapping); |
2ebba6b7 | 1420 | } |
290408d4 | 1421 | |
c33db292 | 1422 | if (!folio_mapped(src)) |
e7e3ffeb | 1423 | rc = move_to_new_folio(dst, src, mode); |
290408d4 | 1424 | |
336bf30e | 1425 | if (page_was_mapped) |
4eecb8b9 MWO |
1426 | remove_migration_ptes(src, |
1427 | rc == MIGRATEPAGE_SUCCESS ? dst : src, false); | |
290408d4 | 1428 | |
c0d0381a | 1429 | unlock_put_anon: |
c33db292 | 1430 | folio_unlock(dst); |
7db7671f HD |
1431 | |
1432 | put_anon: | |
fd4a4663 | 1433 | if (anon_vma) |
9e60109f | 1434 | put_anon_vma(anon_vma); |
8e6ac7fa | 1435 | |
2def7424 | 1436 | if (rc == MIGRATEPAGE_SUCCESS) { |
345c62d1 | 1437 | move_hugetlb_state(src, dst, reason); |
4e096ae1 | 1438 | put_new_folio = NULL; |
2def7424 | 1439 | } |
8e6ac7fa | 1440 | |
cb6acd01 | 1441 | out_unlock: |
c33db292 | 1442 | folio_unlock(src); |
09761333 | 1443 | out: |
dd4ae78a | 1444 | if (rc == MIGRATEPAGE_SUCCESS) |
ea8e72f4 | 1445 | folio_putback_active_hugetlb(src); |
a04840c6 | 1446 | else if (rc != -EAGAIN) |
c33db292 | 1447 | list_move_tail(&src->lru, ret); |
68711a74 DR |
1448 | |
1449 | /* | |
1450 | * If migration was not successful and there's a freeing callback, use | |
1451 | * it. Otherwise, put_page() will drop the reference grabbed during | |
1452 | * isolation. | |
1453 | */ | |
4e096ae1 MWO |
1454 | if (put_new_folio) |
1455 | put_new_folio(dst, private); | |
68711a74 | 1456 | else |
ea8e72f4 | 1457 | folio_putback_active_hugetlb(dst); |
68711a74 | 1458 | |
290408d4 NH |
1459 | return rc; |
1460 | } | |
1461 | ||
eaec4e63 | 1462 | static inline int try_split_folio(struct folio *folio, struct list_head *split_folios) |
d532e2e5 | 1463 | { |
9c62ff00 | 1464 | int rc; |
d532e2e5 | 1465 | |
eaec4e63 HY |
1466 | folio_lock(folio); |
1467 | rc = split_folio_to_list(folio, split_folios); | |
1468 | folio_unlock(folio); | |
e6fa8a79 | 1469 | if (!rc) |
eaec4e63 | 1470 | list_move_tail(&folio->lru, split_folios); |
d532e2e5 YS |
1471 | |
1472 | return rc; | |
1473 | } | |
1474 | ||
42012e04 HY |
1475 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
1476 | #define NR_MAX_BATCHED_MIGRATION HPAGE_PMD_NR | |
1477 | #else | |
1478 | #define NR_MAX_BATCHED_MIGRATION 512 | |
1479 | #endif | |
e5bfff8b | 1480 | #define NR_MAX_MIGRATE_PAGES_RETRY 10 |
2ef7dbb2 HY |
1481 | #define NR_MAX_MIGRATE_ASYNC_RETRY 3 |
1482 | #define NR_MAX_MIGRATE_SYNC_RETRY \ | |
1483 | (NR_MAX_MIGRATE_PAGES_RETRY - NR_MAX_MIGRATE_ASYNC_RETRY) | |
e5bfff8b | 1484 | |
5b855937 HY |
1485 | struct migrate_pages_stats { |
1486 | int nr_succeeded; /* Normal and large folios migrated successfully, in | |
1487 | units of base pages */ | |
1488 | int nr_failed_pages; /* Normal and large folios failed to be migrated, in | |
1489 | units of base pages. Untried folios aren't counted */ | |
1490 | int nr_thp_succeeded; /* THP migrated successfully */ | |
1491 | int nr_thp_failed; /* THP failed to be migrated */ | |
1492 | int nr_thp_split; /* THP split before migrating */ | |
1493 | }; | |
1494 | ||
b20a3503 | 1495 | /* |
e5bfff8b HY |
1496 | * Returns the number of hugetlb folios that were not migrated, or an error code |
1497 | * after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no hugetlb folios are movable | |
1498 | * any more because the list has become empty or no retryable hugetlb folios | |
1499 | * exist any more. It is caller's responsibility to call putback_movable_pages() | |
1500 | * only if ret != 0. | |
b20a3503 | 1501 | */ |
4e096ae1 MWO |
1502 | static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, |
1503 | free_folio_t put_new_folio, unsigned long private, | |
e5bfff8b HY |
1504 | enum migrate_mode mode, int reason, |
1505 | struct migrate_pages_stats *stats, | |
1506 | struct list_head *ret_folios) | |
b20a3503 | 1507 | { |
e24f0b8f | 1508 | int retry = 1; |
e5bfff8b HY |
1509 | int nr_failed = 0; |
1510 | int nr_retry_pages = 0; | |
1511 | int pass = 0; | |
1512 | struct folio *folio, *folio2; | |
1513 | int rc, nr_pages; | |
1514 | ||
1515 | for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && retry; pass++) { | |
1516 | retry = 0; | |
1517 | nr_retry_pages = 0; | |
1518 | ||
1519 | list_for_each_entry_safe(folio, folio2, from, lru) { | |
1520 | if (!folio_test_hugetlb(folio)) | |
1521 | continue; | |
1522 | ||
1523 | nr_pages = folio_nr_pages(folio); | |
1524 | ||
1525 | cond_resched(); | |
1526 | ||
6f7d760e HY |
1527 | /* |
1528 | * Migratability of hugepages depends on architectures and | |
1529 | * their size. This check is necessary because some callers | |
1530 | * of hugepage migration like soft offline and memory | |
1531 | * hotremove don't walk through page tables or check whether | |
1532 | * the hugepage is pmd-based or not before kicking migration. | |
1533 | */ | |
1534 | if (!hugepage_migration_supported(folio_hstate(folio))) { | |
1535 | nr_failed++; | |
1536 | stats->nr_failed_pages += nr_pages; | |
1537 | list_move_tail(&folio->lru, ret_folios); | |
1538 | continue; | |
1539 | } | |
1540 | ||
4e096ae1 MWO |
1541 | rc = unmap_and_move_huge_page(get_new_folio, |
1542 | put_new_folio, private, | |
1543 | folio, pass > 2, mode, | |
e5bfff8b HY |
1544 | reason, ret_folios); |
1545 | /* | |
1546 | * The rules are: | |
1547 | * Success: hugetlb folio will be put back | |
1548 | * -EAGAIN: stay on the from list | |
1549 | * -ENOMEM: stay on the from list | |
e5bfff8b HY |
1550 | * Other errno: put on ret_folios list |
1551 | */ | |
1552 | switch(rc) { | |
e5bfff8b HY |
1553 | case -ENOMEM: |
1554 | /* | |
1555 | * When memory is low, don't bother to try to migrate | |
1556 | * other folios, just exit. | |
1557 | */ | |
1558 | stats->nr_failed_pages += nr_pages + nr_retry_pages; | |
1559 | return -ENOMEM; | |
1560 | case -EAGAIN: | |
1561 | retry++; | |
1562 | nr_retry_pages += nr_pages; | |
1563 | break; | |
1564 | case MIGRATEPAGE_SUCCESS: | |
1565 | stats->nr_succeeded += nr_pages; | |
1566 | break; | |
1567 | default: | |
1568 | /* | |
1569 | * Permanent failure (-EBUSY, etc.): | |
1570 | * unlike -EAGAIN case, the failed folio is | |
1571 | * removed from migration folio list and not | |
1572 | * retried in the next outer loop. | |
1573 | */ | |
1574 | nr_failed++; | |
1575 | stats->nr_failed_pages += nr_pages; | |
1576 | break; | |
1577 | } | |
1578 | } | |
1579 | } | |
1580 | /* | |
1581 | * nr_failed is number of hugetlb folios failed to be migrated. After | |
1582 | * NR_MAX_MIGRATE_PAGES_RETRY attempts, give up and count retried hugetlb | |
1583 | * folios as failed. | |
1584 | */ | |
1585 | nr_failed += retry; | |
1586 | stats->nr_failed_pages += nr_retry_pages; | |
1587 | ||
1588 | return nr_failed; | |
1589 | } | |
1590 | ||
5dfab109 HY |
1591 | /* |
1592 | * migrate_pages_batch() first unmaps folios in the from list as many as | |
1593 | * possible, then move the unmapped folios. | |
fb3592c4 HY |
1594 | * |
1595 | * We only batch migration if mode == MIGRATE_ASYNC to avoid to wait a | |
1596 | * lock or bit when we have locked more than one folio. Which may cause | |
1597 | * deadlock (e.g., for loop device). So, if mode != MIGRATE_ASYNC, the | |
1598 | * length of the from list must be <= 1. | |
5dfab109 | 1599 | */ |
4e096ae1 MWO |
1600 | static int migrate_pages_batch(struct list_head *from, |
1601 | new_folio_t get_new_folio, free_folio_t put_new_folio, | |
1602 | unsigned long private, enum migrate_mode mode, int reason, | |
1603 | struct list_head *ret_folios, struct list_head *split_folios, | |
1604 | struct migrate_pages_stats *stats, int nr_pass) | |
b20a3503 | 1605 | { |
a21d2133 | 1606 | int retry = 1; |
1a5bae25 | 1607 | int thp_retry = 1; |
b20a3503 | 1608 | int nr_failed = 0; |
077309bc | 1609 | int nr_retry_pages = 0; |
b20a3503 | 1610 | int pass = 0; |
1a5bae25 | 1611 | bool is_thp = false; |
5dfab109 | 1612 | struct folio *folio, *folio2, *dst = NULL, *dst2; |
a21d2133 | 1613 | int rc, rc_saved = 0, nr_pages; |
5dfab109 HY |
1614 | LIST_HEAD(unmap_folios); |
1615 | LIST_HEAD(dst_folios); | |
b0b515bf | 1616 | bool nosplit = (reason == MR_NUMA_MISPLACED); |
e5bfff8b | 1617 | |
fb3592c4 HY |
1618 | VM_WARN_ON_ONCE(mode != MIGRATE_ASYNC && |
1619 | !list_empty(from) && !list_is_singular(from)); | |
a21d2133 | 1620 | |
124abced | 1621 | for (pass = 0; pass < nr_pass && retry; pass++) { |
e24f0b8f | 1622 | retry = 0; |
1a5bae25 | 1623 | thp_retry = 0; |
077309bc | 1624 | nr_retry_pages = 0; |
b20a3503 | 1625 | |
eaec4e63 | 1626 | list_for_each_entry_safe(folio, folio2, from, lru) { |
124abced | 1627 | is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); |
eaec4e63 | 1628 | nr_pages = folio_nr_pages(folio); |
e5bfff8b | 1629 | |
e24f0b8f | 1630 | cond_resched(); |
2d1db3b1 | 1631 | |
d532e2e5 | 1632 | /* |
eaec4e63 | 1633 | * Large folio migration might be unsupported or |
6f7d760e | 1634 | * the allocation might be failed so we should retry |
eaec4e63 HY |
1635 | * on the same folio with the large folio split |
1636 | * to normal folios. | |
d532e2e5 | 1637 | * |
eaec4e63 | 1638 | * Split folios are put in split_folios, and |
e6fa8a79 HY |
1639 | * we will migrate them after the rest of the |
1640 | * list is processed. | |
d532e2e5 | 1641 | */ |
6f7d760e | 1642 | if (!thp_migration_supported() && is_thp) { |
124abced | 1643 | nr_failed++; |
6f7d760e | 1644 | stats->nr_thp_failed++; |
a21d2133 | 1645 | if (!try_split_folio(folio, split_folios)) { |
6f7d760e HY |
1646 | stats->nr_thp_split++; |
1647 | continue; | |
f430893b | 1648 | } |
6f7d760e HY |
1649 | stats->nr_failed_pages += nr_pages; |
1650 | list_move_tail(&folio->lru, ret_folios); | |
1651 | continue; | |
1652 | } | |
f430893b | 1653 | |
4e096ae1 MWO |
1654 | rc = migrate_folio_unmap(get_new_folio, put_new_folio, |
1655 | private, folio, &dst, mode, reason, | |
1656 | ret_folios); | |
dd4ae78a YS |
1657 | /* |
1658 | * The rules are: | |
e5bfff8b | 1659 | * Success: folio will be freed |
5dfab109 HY |
1660 | * Unmap: folio will be put on unmap_folios list, |
1661 | * dst folio put on dst_folios list | |
dd4ae78a YS |
1662 | * -EAGAIN: stay on the from list |
1663 | * -ENOMEM: stay on the from list | |
42012e04 | 1664 | * Other errno: put on ret_folios list |
dd4ae78a | 1665 | */ |
e24f0b8f | 1666 | switch(rc) { |
95a402c3 | 1667 | case -ENOMEM: |
94723aaf | 1668 | /* |
d532e2e5 | 1669 | * When memory is low, don't bother to try to migrate |
5dfab109 | 1670 | * other folios, move unmapped folios, then exit. |
94723aaf | 1671 | */ |
124abced HY |
1672 | nr_failed++; |
1673 | stats->nr_thp_failed += is_thp; | |
1674 | /* Large folio NUMA faulting doesn't split to retry. */ | |
1675 | if (folio_test_large(folio) && !nosplit) { | |
1676 | int ret = try_split_folio(folio, split_folios); | |
1677 | ||
1678 | if (!ret) { | |
1679 | stats->nr_thp_split += is_thp; | |
1680 | break; | |
1681 | } else if (reason == MR_LONGTERM_PIN && | |
1682 | ret == -EAGAIN) { | |
1683 | /* | |
1684 | * Try again to split large folio to | |
1685 | * mitigate the failure of longterm pinning. | |
1686 | */ | |
1687 | retry++; | |
1688 | thp_retry += is_thp; | |
1689 | nr_retry_pages += nr_pages; | |
1690 | /* Undo duplicated failure counting. */ | |
1691 | nr_failed--; | |
1692 | stats->nr_thp_failed -= is_thp; | |
1693 | break; | |
94723aaf | 1694 | } |
1a5bae25 | 1695 | } |
b5bade97 | 1696 | |
42012e04 | 1697 | stats->nr_failed_pages += nr_pages + nr_retry_pages; |
fbed53b4 | 1698 | /* nr_failed isn't updated for not used */ |
42012e04 | 1699 | stats->nr_thp_failed += thp_retry; |
5dfab109 HY |
1700 | rc_saved = rc; |
1701 | if (list_empty(&unmap_folios)) | |
1702 | goto out; | |
1703 | else | |
1704 | goto move; | |
e24f0b8f | 1705 | case -EAGAIN: |
124abced HY |
1706 | retry++; |
1707 | thp_retry += is_thp; | |
eaec4e63 | 1708 | nr_retry_pages += nr_pages; |
e24f0b8f | 1709 | break; |
78bd5209 | 1710 | case MIGRATEPAGE_SUCCESS: |
42012e04 HY |
1711 | stats->nr_succeeded += nr_pages; |
1712 | stats->nr_thp_succeeded += is_thp; | |
e24f0b8f | 1713 | break; |
5dfab109 | 1714 | case MIGRATEPAGE_UNMAP: |
5dfab109 HY |
1715 | list_move_tail(&folio->lru, &unmap_folios); |
1716 | list_add_tail(&dst->lru, &dst_folios); | |
e24f0b8f CL |
1717 | break; |
1718 | default: | |
354a3363 | 1719 | /* |
d532e2e5 | 1720 | * Permanent failure (-EBUSY, etc.): |
eaec4e63 HY |
1721 | * unlike -EAGAIN case, the failed folio is |
1722 | * removed from migration folio list and not | |
354a3363 NH |
1723 | * retried in the next outer loop. |
1724 | */ | |
124abced HY |
1725 | nr_failed++; |
1726 | stats->nr_thp_failed += is_thp; | |
42012e04 | 1727 | stats->nr_failed_pages += nr_pages; |
e24f0b8f | 1728 | break; |
2d1db3b1 | 1729 | } |
b20a3503 CL |
1730 | } |
1731 | } | |
7047b5a4 | 1732 | nr_failed += retry; |
42012e04 HY |
1733 | stats->nr_thp_failed += thp_retry; |
1734 | stats->nr_failed_pages += nr_retry_pages; | |
5dfab109 | 1735 | move: |
7e12beb8 HY |
1736 | /* Flush TLBs for all unmapped folios */ |
1737 | try_to_unmap_flush(); | |
1738 | ||
5dfab109 | 1739 | retry = 1; |
124abced | 1740 | for (pass = 0; pass < nr_pass && retry; pass++) { |
5dfab109 | 1741 | retry = 0; |
5dfab109 HY |
1742 | thp_retry = 0; |
1743 | nr_retry_pages = 0; | |
1744 | ||
1745 | dst = list_first_entry(&dst_folios, struct folio, lru); | |
1746 | dst2 = list_next_entry(dst, lru); | |
1747 | list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { | |
124abced | 1748 | is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); |
5dfab109 HY |
1749 | nr_pages = folio_nr_pages(folio); |
1750 | ||
1751 | cond_resched(); | |
1752 | ||
4e096ae1 | 1753 | rc = migrate_folio_move(put_new_folio, private, |
5dfab109 HY |
1754 | folio, dst, mode, |
1755 | reason, ret_folios); | |
1756 | /* | |
1757 | * The rules are: | |
1758 | * Success: folio will be freed | |
1759 | * -EAGAIN: stay on the unmap_folios list | |
1760 | * Other errno: put on ret_folios list | |
1761 | */ | |
1762 | switch(rc) { | |
1763 | case -EAGAIN: | |
124abced HY |
1764 | retry++; |
1765 | thp_retry += is_thp; | |
5dfab109 HY |
1766 | nr_retry_pages += nr_pages; |
1767 | break; | |
1768 | case MIGRATEPAGE_SUCCESS: | |
1769 | stats->nr_succeeded += nr_pages; | |
1770 | stats->nr_thp_succeeded += is_thp; | |
1771 | break; | |
1772 | default: | |
124abced HY |
1773 | nr_failed++; |
1774 | stats->nr_thp_failed += is_thp; | |
5dfab109 | 1775 | stats->nr_failed_pages += nr_pages; |
e24f0b8f | 1776 | break; |
2d1db3b1 | 1777 | } |
5dfab109 HY |
1778 | dst = dst2; |
1779 | dst2 = list_next_entry(dst, lru); | |
b20a3503 CL |
1780 | } |
1781 | } | |
7047b5a4 | 1782 | nr_failed += retry; |
5dfab109 HY |
1783 | stats->nr_thp_failed += thp_retry; |
1784 | stats->nr_failed_pages += nr_retry_pages; | |
1785 | ||
124abced | 1786 | rc = rc_saved ? : nr_failed; |
5dfab109 HY |
1787 | out: |
1788 | /* Cleanup remaining folios */ | |
1789 | dst = list_first_entry(&dst_folios, struct folio, lru); | |
1790 | dst2 = list_next_entry(dst, lru); | |
1791 | list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { | |
1792 | int page_was_mapped = 0; | |
1793 | struct anon_vma *anon_vma = NULL; | |
1794 | ||
1795 | __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); | |
1796 | migrate_folio_undo_src(folio, page_was_mapped, anon_vma, | |
ebe75e47 | 1797 | true, ret_folios); |
5dfab109 | 1798 | list_del(&dst->lru); |
4e096ae1 | 1799 | migrate_folio_undo_dst(dst, true, put_new_folio, private); |
5dfab109 HY |
1800 | dst = dst2; |
1801 | dst2 = list_next_entry(dst, lru); | |
1802 | } | |
1803 | ||
42012e04 HY |
1804 | return rc; |
1805 | } | |
1806 | ||
4e096ae1 MWO |
1807 | static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio, |
1808 | free_folio_t put_new_folio, unsigned long private, | |
1809 | enum migrate_mode mode, int reason, | |
1810 | struct list_head *ret_folios, struct list_head *split_folios, | |
1811 | struct migrate_pages_stats *stats) | |
2ef7dbb2 HY |
1812 | { |
1813 | int rc, nr_failed = 0; | |
1814 | LIST_HEAD(folios); | |
1815 | struct migrate_pages_stats astats; | |
1816 | ||
1817 | memset(&astats, 0, sizeof(astats)); | |
1818 | /* Try to migrate in batch with MIGRATE_ASYNC mode firstly */ | |
4e096ae1 | 1819 | rc = migrate_pages_batch(from, get_new_folio, put_new_folio, private, MIGRATE_ASYNC, |
2ef7dbb2 HY |
1820 | reason, &folios, split_folios, &astats, |
1821 | NR_MAX_MIGRATE_ASYNC_RETRY); | |
1822 | stats->nr_succeeded += astats.nr_succeeded; | |
1823 | stats->nr_thp_succeeded += astats.nr_thp_succeeded; | |
1824 | stats->nr_thp_split += astats.nr_thp_split; | |
1825 | if (rc < 0) { | |
1826 | stats->nr_failed_pages += astats.nr_failed_pages; | |
1827 | stats->nr_thp_failed += astats.nr_thp_failed; | |
1828 | list_splice_tail(&folios, ret_folios); | |
1829 | return rc; | |
1830 | } | |
1831 | stats->nr_thp_failed += astats.nr_thp_split; | |
1832 | nr_failed += astats.nr_thp_split; | |
1833 | /* | |
1834 | * Fall back to migrate all failed folios one by one synchronously. All | |
1835 | * failed folios except split THPs will be retried, so their failure | |
1836 | * isn't counted | |
1837 | */ | |
1838 | list_splice_tail_init(&folios, from); | |
1839 | while (!list_empty(from)) { | |
1840 | list_move(from->next, &folios); | |
4e096ae1 | 1841 | rc = migrate_pages_batch(&folios, get_new_folio, put_new_folio, |
2ef7dbb2 HY |
1842 | private, mode, reason, ret_folios, |
1843 | split_folios, stats, NR_MAX_MIGRATE_SYNC_RETRY); | |
1844 | list_splice_tail_init(&folios, ret_folios); | |
1845 | if (rc < 0) | |
1846 | return rc; | |
1847 | nr_failed += rc; | |
1848 | } | |
1849 | ||
1850 | return nr_failed; | |
1851 | } | |
1852 | ||
42012e04 HY |
1853 | /* |
1854 | * migrate_pages - migrate the folios specified in a list, to the free folios | |
1855 | * supplied as the target for the page migration | |
1856 | * | |
1857 | * @from: The list of folios to be migrated. | |
4e096ae1 | 1858 | * @get_new_folio: The function used to allocate free folios to be used |
42012e04 | 1859 | * as the target of the folio migration. |
4e096ae1 | 1860 | * @put_new_folio: The function used to free target folios if migration |
42012e04 | 1861 | * fails, or NULL if no special handling is necessary. |
4e096ae1 | 1862 | * @private: Private data to be passed on to get_new_folio() |
42012e04 HY |
1863 | * @mode: The migration mode that specifies the constraints for |
1864 | * folio migration, if any. | |
1865 | * @reason: The reason for folio migration. | |
1866 | * @ret_succeeded: Set to the number of folios migrated successfully if | |
1867 | * the caller passes a non-NULL pointer. | |
1868 | * | |
1869 | * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios | |
1870 | * are movable any more because the list has become empty or no retryable folios | |
1871 | * exist any more. It is caller's responsibility to call putback_movable_pages() | |
1872 | * only if ret != 0. | |
1873 | * | |
1874 | * Returns the number of {normal folio, large folio, hugetlb} that were not | |
1875 | * migrated, or an error code. The number of large folio splits will be | |
1876 | * considered as the number of non-migrated large folio, no matter how many | |
1877 | * split folios of the large folio are migrated successfully. | |
1878 | */ | |
4e096ae1 MWO |
1879 | int migrate_pages(struct list_head *from, new_folio_t get_new_folio, |
1880 | free_folio_t put_new_folio, unsigned long private, | |
42012e04 HY |
1881 | enum migrate_mode mode, int reason, unsigned int *ret_succeeded) |
1882 | { | |
1883 | int rc, rc_gather; | |
2ef7dbb2 | 1884 | int nr_pages; |
42012e04 HY |
1885 | struct folio *folio, *folio2; |
1886 | LIST_HEAD(folios); | |
1887 | LIST_HEAD(ret_folios); | |
a21d2133 | 1888 | LIST_HEAD(split_folios); |
42012e04 HY |
1889 | struct migrate_pages_stats stats; |
1890 | ||
1891 | trace_mm_migrate_pages_start(mode, reason); | |
1892 | ||
1893 | memset(&stats, 0, sizeof(stats)); | |
1894 | ||
4e096ae1 | 1895 | rc_gather = migrate_hugetlbs(from, get_new_folio, put_new_folio, private, |
42012e04 HY |
1896 | mode, reason, &stats, &ret_folios); |
1897 | if (rc_gather < 0) | |
1898 | goto out; | |
fb3592c4 | 1899 | |
42012e04 HY |
1900 | again: |
1901 | nr_pages = 0; | |
1902 | list_for_each_entry_safe(folio, folio2, from, lru) { | |
1903 | /* Retried hugetlb folios will be kept in list */ | |
1904 | if (folio_test_hugetlb(folio)) { | |
1905 | list_move_tail(&folio->lru, &ret_folios); | |
1906 | continue; | |
1907 | } | |
1908 | ||
1909 | nr_pages += folio_nr_pages(folio); | |
2ef7dbb2 | 1910 | if (nr_pages >= NR_MAX_BATCHED_MIGRATION) |
42012e04 HY |
1911 | break; |
1912 | } | |
2ef7dbb2 | 1913 | if (nr_pages >= NR_MAX_BATCHED_MIGRATION) |
fb3592c4 | 1914 | list_cut_before(&folios, from, &folio2->lru); |
42012e04 HY |
1915 | else |
1916 | list_splice_init(from, &folios); | |
2ef7dbb2 | 1917 | if (mode == MIGRATE_ASYNC) |
4e096ae1 MWO |
1918 | rc = migrate_pages_batch(&folios, get_new_folio, put_new_folio, |
1919 | private, mode, reason, &ret_folios, | |
1920 | &split_folios, &stats, | |
1921 | NR_MAX_MIGRATE_PAGES_RETRY); | |
2ef7dbb2 | 1922 | else |
4e096ae1 MWO |
1923 | rc = migrate_pages_sync(&folios, get_new_folio, put_new_folio, |
1924 | private, mode, reason, &ret_folios, | |
1925 | &split_folios, &stats); | |
42012e04 HY |
1926 | list_splice_tail_init(&folios, &ret_folios); |
1927 | if (rc < 0) { | |
1928 | rc_gather = rc; | |
a21d2133 | 1929 | list_splice_tail(&split_folios, &ret_folios); |
42012e04 HY |
1930 | goto out; |
1931 | } | |
a21d2133 HY |
1932 | if (!list_empty(&split_folios)) { |
1933 | /* | |
1934 | * Failure isn't counted since all split folios of a large folio | |
1935 | * is counted as 1 failure already. And, we only try to migrate | |
1936 | * with minimal effort, force MIGRATE_ASYNC mode and retry once. | |
1937 | */ | |
4e096ae1 MWO |
1938 | migrate_pages_batch(&split_folios, get_new_folio, |
1939 | put_new_folio, private, MIGRATE_ASYNC, reason, | |
1940 | &ret_folios, NULL, &stats, 1); | |
a21d2133 HY |
1941 | list_splice_tail_init(&split_folios, &ret_folios); |
1942 | } | |
42012e04 HY |
1943 | rc_gather += rc; |
1944 | if (!list_empty(from)) | |
1945 | goto again; | |
95a402c3 | 1946 | out: |
dd4ae78a | 1947 | /* |
eaec4e63 | 1948 | * Put the permanent failure folio back to migration list, they |
dd4ae78a YS |
1949 | * will be put back to the right list by the caller. |
1950 | */ | |
eaec4e63 | 1951 | list_splice(&ret_folios, from); |
dd4ae78a | 1952 | |
03e5f82e | 1953 | /* |
eaec4e63 HY |
1954 | * Return 0 in case all split folios of fail-to-migrate large folios |
1955 | * are migrated successfully. | |
03e5f82e BW |
1956 | */ |
1957 | if (list_empty(from)) | |
42012e04 | 1958 | rc_gather = 0; |
03e5f82e | 1959 | |
5b855937 HY |
1960 | count_vm_events(PGMIGRATE_SUCCESS, stats.nr_succeeded); |
1961 | count_vm_events(PGMIGRATE_FAIL, stats.nr_failed_pages); | |
1962 | count_vm_events(THP_MIGRATION_SUCCESS, stats.nr_thp_succeeded); | |
1963 | count_vm_events(THP_MIGRATION_FAIL, stats.nr_thp_failed); | |
1964 | count_vm_events(THP_MIGRATION_SPLIT, stats.nr_thp_split); | |
1965 | trace_mm_migrate_pages(stats.nr_succeeded, stats.nr_failed_pages, | |
1966 | stats.nr_thp_succeeded, stats.nr_thp_failed, | |
1967 | stats.nr_thp_split, mode, reason); | |
7b2a2d4a | 1968 | |
5ac95884 | 1969 | if (ret_succeeded) |
5b855937 | 1970 | *ret_succeeded = stats.nr_succeeded; |
5ac95884 | 1971 | |
42012e04 | 1972 | return rc_gather; |
b20a3503 | 1973 | } |
95a402c3 | 1974 | |
4e096ae1 | 1975 | struct folio *alloc_migration_target(struct folio *src, unsigned long private) |
b4b38223 | 1976 | { |
19fc7bed JK |
1977 | struct migration_target_control *mtc; |
1978 | gfp_t gfp_mask; | |
b4b38223 | 1979 | unsigned int order = 0; |
19fc7bed JK |
1980 | int nid; |
1981 | int zidx; | |
1982 | ||
1983 | mtc = (struct migration_target_control *)private; | |
1984 | gfp_mask = mtc->gfp_mask; | |
1985 | nid = mtc->nid; | |
1986 | if (nid == NUMA_NO_NODE) | |
4e096ae1 | 1987 | nid = folio_nid(src); |
b4b38223 | 1988 | |
4e096ae1 MWO |
1989 | if (folio_test_hugetlb(src)) { |
1990 | struct hstate *h = folio_hstate(src); | |
d92bbc27 | 1991 | |
19fc7bed | 1992 | gfp_mask = htlb_modify_alloc_mask(h, gfp_mask); |
4e096ae1 | 1993 | return alloc_hugetlb_folio_nodemask(h, nid, |
e37d3e83 | 1994 | mtc->nmask, gfp_mask); |
d92bbc27 | 1995 | } |
b4b38223 | 1996 | |
4e096ae1 | 1997 | if (folio_test_large(src)) { |
9933a0c8 JK |
1998 | /* |
1999 | * clear __GFP_RECLAIM to make the migration callback | |
2000 | * consistent with regular THP allocations. | |
2001 | */ | |
2002 | gfp_mask &= ~__GFP_RECLAIM; | |
b4b38223 | 2003 | gfp_mask |= GFP_TRANSHUGE; |
4e096ae1 | 2004 | order = folio_order(src); |
b4b38223 | 2005 | } |
4e096ae1 | 2006 | zidx = zone_idx(folio_zone(src)); |
19fc7bed | 2007 | if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE) |
b4b38223 JK |
2008 | gfp_mask |= __GFP_HIGHMEM; |
2009 | ||
4e096ae1 | 2010 | return __folio_alloc(gfp_mask, order, nid, mtc->nmask); |
b4b38223 JK |
2011 | } |
2012 | ||
742755a1 | 2013 | #ifdef CONFIG_NUMA |
742755a1 | 2014 | |
a49bd4d7 | 2015 | static int store_status(int __user *status, int start, int value, int nr) |
742755a1 | 2016 | { |
a49bd4d7 MH |
2017 | while (nr-- > 0) { |
2018 | if (put_user(value, status + start)) | |
2019 | return -EFAULT; | |
2020 | start++; | |
2021 | } | |
2022 | ||
2023 | return 0; | |
2024 | } | |
2025 | ||
2026 | static int do_move_pages_to_node(struct mm_struct *mm, | |
2027 | struct list_head *pagelist, int node) | |
2028 | { | |
2029 | int err; | |
a0976311 JK |
2030 | struct migration_target_control mtc = { |
2031 | .nid = node, | |
2032 | .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, | |
2033 | }; | |
a49bd4d7 | 2034 | |
a0976311 | 2035 | err = migrate_pages(pagelist, alloc_migration_target, NULL, |
5ac95884 | 2036 | (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL); |
a49bd4d7 MH |
2037 | if (err) |
2038 | putback_movable_pages(pagelist); | |
2039 | return err; | |
742755a1 CL |
2040 | } |
2041 | ||
2042 | /* | |
a49bd4d7 MH |
2043 | * Resolves the given address to a struct page, isolates it from the LRU and |
2044 | * puts it to the given pagelist. | |
e0153fc2 YS |
2045 | * Returns: |
2046 | * errno - if the page cannot be found/isolated | |
2047 | * 0 - when it doesn't have to be migrated because it is already on the | |
2048 | * target node | |
2049 | * 1 - when it has been queued | |
742755a1 | 2050 | */ |
428e106a | 2051 | static int add_page_for_migration(struct mm_struct *mm, const void __user *p, |
a49bd4d7 | 2052 | int node, struct list_head *pagelist, bool migrate_all) |
742755a1 | 2053 | { |
a49bd4d7 | 2054 | struct vm_area_struct *vma; |
428e106a | 2055 | unsigned long addr; |
a49bd4d7 | 2056 | struct page *page; |
742755a1 | 2057 | int err; |
9747b9e9 | 2058 | bool isolated; |
742755a1 | 2059 | |
d8ed45c5 | 2060 | mmap_read_lock(mm); |
428e106a KS |
2061 | addr = (unsigned long)untagged_addr_remote(mm, p); |
2062 | ||
a49bd4d7 | 2063 | err = -EFAULT; |
cb1c37b1 ML |
2064 | vma = vma_lookup(mm, addr); |
2065 | if (!vma || !vma_migratable(vma)) | |
a49bd4d7 | 2066 | goto out; |
742755a1 | 2067 | |
a49bd4d7 | 2068 | /* FOLL_DUMP to ignore special (like zero) pages */ |
87d2762e | 2069 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
89f5b7da | 2070 | |
a49bd4d7 MH |
2071 | err = PTR_ERR(page); |
2072 | if (IS_ERR(page)) | |
2073 | goto out; | |
89f5b7da | 2074 | |
a49bd4d7 | 2075 | err = -ENOENT; |
f7091ed6 | 2076 | if (!page) |
a49bd4d7 | 2077 | goto out; |
742755a1 | 2078 | |
f7091ed6 HW |
2079 | if (is_zone_device_page(page)) |
2080 | goto out_putpage; | |
2081 | ||
a49bd4d7 MH |
2082 | err = 0; |
2083 | if (page_to_nid(page) == node) | |
2084 | goto out_putpage; | |
742755a1 | 2085 | |
a49bd4d7 MH |
2086 | err = -EACCES; |
2087 | if (page_mapcount(page) > 1 && !migrate_all) | |
2088 | goto out_putpage; | |
742755a1 | 2089 | |
a49bd4d7 MH |
2090 | if (PageHuge(page)) { |
2091 | if (PageHead(page)) { | |
9747b9e9 BW |
2092 | isolated = isolate_hugetlb(page_folio(page), pagelist); |
2093 | err = isolated ? 1 : -EBUSY; | |
e632a938 | 2094 | } |
a49bd4d7 MH |
2095 | } else { |
2096 | struct page *head; | |
e632a938 | 2097 | |
e8db67eb | 2098 | head = compound_head(page); |
f7f9c00d BW |
2099 | isolated = isolate_lru_page(head); |
2100 | if (!isolated) { | |
2101 | err = -EBUSY; | |
a49bd4d7 | 2102 | goto out_putpage; |
f7f9c00d | 2103 | } |
742755a1 | 2104 | |
e0153fc2 | 2105 | err = 1; |
a49bd4d7 MH |
2106 | list_add_tail(&head->lru, pagelist); |
2107 | mod_node_page_state(page_pgdat(head), | |
9de4f22a | 2108 | NR_ISOLATED_ANON + page_is_file_lru(head), |
6c357848 | 2109 | thp_nr_pages(head)); |
a49bd4d7 MH |
2110 | } |
2111 | out_putpage: | |
2112 | /* | |
2113 | * Either remove the duplicate refcount from | |
2114 | * isolate_lru_page() or drop the page ref if it was | |
2115 | * not isolated. | |
2116 | */ | |
2117 | put_page(page); | |
2118 | out: | |
d8ed45c5 | 2119 | mmap_read_unlock(mm); |
742755a1 CL |
2120 | return err; |
2121 | } | |
2122 | ||
7ca8783a WY |
2123 | static int move_pages_and_store_status(struct mm_struct *mm, int node, |
2124 | struct list_head *pagelist, int __user *status, | |
2125 | int start, int i, unsigned long nr_pages) | |
2126 | { | |
2127 | int err; | |
2128 | ||
5d7ae891 WY |
2129 | if (list_empty(pagelist)) |
2130 | return 0; | |
2131 | ||
7ca8783a WY |
2132 | err = do_move_pages_to_node(mm, pagelist, node); |
2133 | if (err) { | |
2134 | /* | |
2135 | * Positive err means the number of failed | |
2136 | * pages to migrate. Since we are going to | |
2137 | * abort and return the number of non-migrated | |
ab9dd4f8 | 2138 | * pages, so need to include the rest of the |
7ca8783a WY |
2139 | * nr_pages that have not been attempted as |
2140 | * well. | |
2141 | */ | |
2142 | if (err > 0) | |
a7504ed1 | 2143 | err += nr_pages - i; |
7ca8783a WY |
2144 | return err; |
2145 | } | |
2146 | return store_status(status, start, node, i - start); | |
2147 | } | |
2148 | ||
5e9a0f02 BG |
2149 | /* |
2150 | * Migrate an array of page address onto an array of nodes and fill | |
2151 | * the corresponding array of status. | |
2152 | */ | |
3268c63e | 2153 | static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, |
5e9a0f02 BG |
2154 | unsigned long nr_pages, |
2155 | const void __user * __user *pages, | |
2156 | const int __user *nodes, | |
2157 | int __user *status, int flags) | |
2158 | { | |
a49bd4d7 MH |
2159 | int current_node = NUMA_NO_NODE; |
2160 | LIST_HEAD(pagelist); | |
2161 | int start, i; | |
2162 | int err = 0, err1; | |
35282a2d | 2163 | |
361a2a22 | 2164 | lru_cache_disable(); |
35282a2d | 2165 | |
a49bd4d7 MH |
2166 | for (i = start = 0; i < nr_pages; i++) { |
2167 | const void __user *p; | |
a49bd4d7 | 2168 | int node; |
3140a227 | 2169 | |
a49bd4d7 MH |
2170 | err = -EFAULT; |
2171 | if (get_user(p, pages + i)) | |
2172 | goto out_flush; | |
2173 | if (get_user(node, nodes + i)) | |
2174 | goto out_flush; | |
a49bd4d7 MH |
2175 | |
2176 | err = -ENODEV; | |
2177 | if (node < 0 || node >= MAX_NUMNODES) | |
2178 | goto out_flush; | |
2179 | if (!node_state(node, N_MEMORY)) | |
2180 | goto out_flush; | |
5e9a0f02 | 2181 | |
a49bd4d7 MH |
2182 | err = -EACCES; |
2183 | if (!node_isset(node, task_nodes)) | |
2184 | goto out_flush; | |
2185 | ||
2186 | if (current_node == NUMA_NO_NODE) { | |
2187 | current_node = node; | |
2188 | start = i; | |
2189 | } else if (node != current_node) { | |
7ca8783a WY |
2190 | err = move_pages_and_store_status(mm, current_node, |
2191 | &pagelist, status, start, i, nr_pages); | |
a49bd4d7 MH |
2192 | if (err) |
2193 | goto out; | |
2194 | start = i; | |
2195 | current_node = node; | |
3140a227 BG |
2196 | } |
2197 | ||
a49bd4d7 MH |
2198 | /* |
2199 | * Errors in the page lookup or isolation are not fatal and we simply | |
2200 | * report them via status | |
2201 | */ | |
428e106a KS |
2202 | err = add_page_for_migration(mm, p, current_node, &pagelist, |
2203 | flags & MPOL_MF_MOVE_ALL); | |
e0153fc2 | 2204 | |
d08221a0 | 2205 | if (err > 0) { |
e0153fc2 YS |
2206 | /* The page is successfully queued for migration */ |
2207 | continue; | |
2208 | } | |
3140a227 | 2209 | |
65462462 JH |
2210 | /* |
2211 | * The move_pages() man page does not have an -EEXIST choice, so | |
2212 | * use -EFAULT instead. | |
2213 | */ | |
2214 | if (err == -EEXIST) | |
2215 | err = -EFAULT; | |
2216 | ||
d08221a0 WY |
2217 | /* |
2218 | * If the page is already on the target node (!err), store the | |
2219 | * node, otherwise, store the err. | |
2220 | */ | |
2221 | err = store_status(status, i, err ? : current_node, 1); | |
a49bd4d7 MH |
2222 | if (err) |
2223 | goto out_flush; | |
5e9a0f02 | 2224 | |
7ca8783a WY |
2225 | err = move_pages_and_store_status(mm, current_node, &pagelist, |
2226 | status, start, i, nr_pages); | |
a7504ed1 HY |
2227 | if (err) { |
2228 | /* We have accounted for page i */ | |
2229 | if (err > 0) | |
2230 | err--; | |
4afdacec | 2231 | goto out; |
a7504ed1 | 2232 | } |
a49bd4d7 | 2233 | current_node = NUMA_NO_NODE; |
3140a227 | 2234 | } |
a49bd4d7 MH |
2235 | out_flush: |
2236 | /* Make sure we do not overwrite the existing error */ | |
7ca8783a WY |
2237 | err1 = move_pages_and_store_status(mm, current_node, &pagelist, |
2238 | status, start, i, nr_pages); | |
dfe9aa23 | 2239 | if (err >= 0) |
a49bd4d7 | 2240 | err = err1; |
5e9a0f02 | 2241 | out: |
361a2a22 | 2242 | lru_cache_enable(); |
5e9a0f02 BG |
2243 | return err; |
2244 | } | |
2245 | ||
742755a1 | 2246 | /* |
2f007e74 | 2247 | * Determine the nodes of an array of pages and store it in an array of status. |
742755a1 | 2248 | */ |
80bba129 BG |
2249 | static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, |
2250 | const void __user **pages, int *status) | |
742755a1 | 2251 | { |
2f007e74 | 2252 | unsigned long i; |
2f007e74 | 2253 | |
d8ed45c5 | 2254 | mmap_read_lock(mm); |
742755a1 | 2255 | |
2f007e74 | 2256 | for (i = 0; i < nr_pages; i++) { |
80bba129 | 2257 | unsigned long addr = (unsigned long)(*pages); |
742755a1 CL |
2258 | struct vm_area_struct *vma; |
2259 | struct page *page; | |
c095adbc | 2260 | int err = -EFAULT; |
2f007e74 | 2261 | |
059b8b48 LH |
2262 | vma = vma_lookup(mm, addr); |
2263 | if (!vma) | |
742755a1 CL |
2264 | goto set_status; |
2265 | ||
d899844e | 2266 | /* FOLL_DUMP to ignore special (like zero) pages */ |
16fd6b31 | 2267 | page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); |
89f5b7da LT |
2268 | |
2269 | err = PTR_ERR(page); | |
2270 | if (IS_ERR(page)) | |
2271 | goto set_status; | |
2272 | ||
f7091ed6 HW |
2273 | err = -ENOENT; |
2274 | if (!page) | |
2275 | goto set_status; | |
2276 | ||
2277 | if (!is_zone_device_page(page)) | |
4cd61484 | 2278 | err = page_to_nid(page); |
f7091ed6 | 2279 | |
16fd6b31 | 2280 | put_page(page); |
742755a1 | 2281 | set_status: |
80bba129 BG |
2282 | *status = err; |
2283 | ||
2284 | pages++; | |
2285 | status++; | |
2286 | } | |
2287 | ||
d8ed45c5 | 2288 | mmap_read_unlock(mm); |
80bba129 BG |
2289 | } |
2290 | ||
5b1b561b AB |
2291 | static int get_compat_pages_array(const void __user *chunk_pages[], |
2292 | const void __user * __user *pages, | |
2293 | unsigned long chunk_nr) | |
2294 | { | |
2295 | compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages; | |
2296 | compat_uptr_t p; | |
2297 | int i; | |
2298 | ||
2299 | for (i = 0; i < chunk_nr; i++) { | |
2300 | if (get_user(p, pages32 + i)) | |
2301 | return -EFAULT; | |
2302 | chunk_pages[i] = compat_ptr(p); | |
2303 | } | |
2304 | ||
2305 | return 0; | |
2306 | } | |
2307 | ||
80bba129 BG |
2308 | /* |
2309 | * Determine the nodes of a user array of pages and store it in | |
2310 | * a user array of status. | |
2311 | */ | |
2312 | static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, | |
2313 | const void __user * __user *pages, | |
2314 | int __user *status) | |
2315 | { | |
3eefb826 | 2316 | #define DO_PAGES_STAT_CHUNK_NR 16UL |
80bba129 BG |
2317 | const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; |
2318 | int chunk_status[DO_PAGES_STAT_CHUNK_NR]; | |
80bba129 | 2319 | |
87b8d1ad | 2320 | while (nr_pages) { |
3eefb826 | 2321 | unsigned long chunk_nr = min(nr_pages, DO_PAGES_STAT_CHUNK_NR); |
87b8d1ad | 2322 | |
5b1b561b AB |
2323 | if (in_compat_syscall()) { |
2324 | if (get_compat_pages_array(chunk_pages, pages, | |
2325 | chunk_nr)) | |
2326 | break; | |
2327 | } else { | |
2328 | if (copy_from_user(chunk_pages, pages, | |
2329 | chunk_nr * sizeof(*chunk_pages))) | |
2330 | break; | |
2331 | } | |
80bba129 BG |
2332 | |
2333 | do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); | |
2334 | ||
87b8d1ad PA |
2335 | if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) |
2336 | break; | |
742755a1 | 2337 | |
87b8d1ad PA |
2338 | pages += chunk_nr; |
2339 | status += chunk_nr; | |
2340 | nr_pages -= chunk_nr; | |
2341 | } | |
2342 | return nr_pages ? -EFAULT : 0; | |
742755a1 CL |
2343 | } |
2344 | ||
4dc200ce | 2345 | static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) |
742755a1 | 2346 | { |
742755a1 | 2347 | struct task_struct *task; |
742755a1 | 2348 | struct mm_struct *mm; |
742755a1 | 2349 | |
4dc200ce ML |
2350 | /* |
2351 | * There is no need to check if current process has the right to modify | |
2352 | * the specified process when they are same. | |
2353 | */ | |
2354 | if (!pid) { | |
2355 | mmget(current->mm); | |
2356 | *mem_nodes = cpuset_mems_allowed(current); | |
2357 | return current->mm; | |
2358 | } | |
742755a1 CL |
2359 | |
2360 | /* Find the mm_struct */ | |
a879bf58 | 2361 | rcu_read_lock(); |
4dc200ce | 2362 | task = find_task_by_vpid(pid); |
742755a1 | 2363 | if (!task) { |
a879bf58 | 2364 | rcu_read_unlock(); |
4dc200ce | 2365 | return ERR_PTR(-ESRCH); |
742755a1 | 2366 | } |
3268c63e | 2367 | get_task_struct(task); |
742755a1 CL |
2368 | |
2369 | /* | |
2370 | * Check if this process has the right to modify the specified | |
197e7e52 | 2371 | * process. Use the regular "ptrace_may_access()" checks. |
742755a1 | 2372 | */ |
197e7e52 | 2373 | if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) { |
c69e8d9c | 2374 | rcu_read_unlock(); |
4dc200ce | 2375 | mm = ERR_PTR(-EPERM); |
5e9a0f02 | 2376 | goto out; |
742755a1 | 2377 | } |
c69e8d9c | 2378 | rcu_read_unlock(); |
742755a1 | 2379 | |
4dc200ce ML |
2380 | mm = ERR_PTR(security_task_movememory(task)); |
2381 | if (IS_ERR(mm)) | |
5e9a0f02 | 2382 | goto out; |
4dc200ce | 2383 | *mem_nodes = cpuset_mems_allowed(task); |
3268c63e | 2384 | mm = get_task_mm(task); |
4dc200ce | 2385 | out: |
3268c63e | 2386 | put_task_struct(task); |
6e8b09ea | 2387 | if (!mm) |
4dc200ce ML |
2388 | mm = ERR_PTR(-EINVAL); |
2389 | return mm; | |
2390 | } | |
2391 | ||
2392 | /* | |
2393 | * Move a list of pages in the address space of the currently executing | |
2394 | * process. | |
2395 | */ | |
2396 | static int kernel_move_pages(pid_t pid, unsigned long nr_pages, | |
2397 | const void __user * __user *pages, | |
2398 | const int __user *nodes, | |
2399 | int __user *status, int flags) | |
2400 | { | |
2401 | struct mm_struct *mm; | |
2402 | int err; | |
2403 | nodemask_t task_nodes; | |
2404 | ||
2405 | /* Check flags */ | |
2406 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
6e8b09ea SL |
2407 | return -EINVAL; |
2408 | ||
4dc200ce ML |
2409 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) |
2410 | return -EPERM; | |
2411 | ||
2412 | mm = find_mm_struct(pid, &task_nodes); | |
2413 | if (IS_ERR(mm)) | |
2414 | return PTR_ERR(mm); | |
2415 | ||
6e8b09ea SL |
2416 | if (nodes) |
2417 | err = do_pages_move(mm, task_nodes, nr_pages, pages, | |
2418 | nodes, status, flags); | |
2419 | else | |
2420 | err = do_pages_stat(mm, nr_pages, pages, status); | |
742755a1 | 2421 | |
742755a1 CL |
2422 | mmput(mm); |
2423 | return err; | |
2424 | } | |
742755a1 | 2425 | |
7addf443 DB |
2426 | SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, |
2427 | const void __user * __user *, pages, | |
2428 | const int __user *, nodes, | |
2429 | int __user *, status, int, flags) | |
2430 | { | |
2431 | return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags); | |
2432 | } | |
2433 | ||
7039e1db PZ |
2434 | #ifdef CONFIG_NUMA_BALANCING |
2435 | /* | |
2436 | * Returns true if this is a safe migration target node for misplaced NUMA | |
bc53008e | 2437 | * pages. Currently it only checks the watermarks which is crude. |
7039e1db PZ |
2438 | */ |
2439 | static bool migrate_balanced_pgdat(struct pglist_data *pgdat, | |
3abef4e6 | 2440 | unsigned long nr_migrate_pages) |
7039e1db PZ |
2441 | { |
2442 | int z; | |
599d0c95 | 2443 | |
7039e1db PZ |
2444 | for (z = pgdat->nr_zones - 1; z >= 0; z--) { |
2445 | struct zone *zone = pgdat->node_zones + z; | |
2446 | ||
bc53008e | 2447 | if (!managed_zone(zone)) |
7039e1db PZ |
2448 | continue; |
2449 | ||
7039e1db PZ |
2450 | /* Avoid waking kswapd by allocating pages_to_migrate pages. */ |
2451 | if (!zone_watermark_ok(zone, 0, | |
2452 | high_wmark_pages(zone) + | |
2453 | nr_migrate_pages, | |
bfe9d006 | 2454 | ZONE_MOVABLE, 0)) |
7039e1db PZ |
2455 | continue; |
2456 | return true; | |
2457 | } | |
2458 | return false; | |
2459 | } | |
2460 | ||
4e096ae1 | 2461 | static struct folio *alloc_misplaced_dst_folio(struct folio *src, |
666feb21 | 2462 | unsigned long data) |
7039e1db PZ |
2463 | { |
2464 | int nid = (int) data; | |
4e096ae1 | 2465 | int order = folio_order(src); |
c185e494 | 2466 | gfp_t gfp = __GFP_THISNODE; |
c185e494 MWO |
2467 | |
2468 | if (order > 0) | |
2469 | gfp |= GFP_TRANSHUGE_LIGHT; | |
2470 | else { | |
2471 | gfp |= GFP_HIGHUSER_MOVABLE | __GFP_NOMEMALLOC | __GFP_NORETRY | | |
2472 | __GFP_NOWARN; | |
2473 | gfp &= ~__GFP_RECLAIM; | |
2474 | } | |
4e096ae1 | 2475 | return __folio_alloc_node(gfp, order, nid); |
c5b5a3dd YS |
2476 | } |
2477 | ||
1c30e017 | 2478 | static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) |
b32967ff | 2479 | { |
2b9b624f | 2480 | int nr_pages = thp_nr_pages(page); |
c574bbe9 | 2481 | int order = compound_order(page); |
a8f60772 | 2482 | |
c574bbe9 | 2483 | VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); |
3abef4e6 | 2484 | |
662aeea7 YS |
2485 | /* Do not migrate THP mapped by multiple processes */ |
2486 | if (PageTransHuge(page) && total_mapcount(page) > 1) | |
2487 | return 0; | |
2488 | ||
7039e1db | 2489 | /* Avoid migrating to a node that is nearly full */ |
c574bbe9 HY |
2490 | if (!migrate_balanced_pgdat(pgdat, nr_pages)) { |
2491 | int z; | |
2492 | ||
2493 | if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)) | |
2494 | return 0; | |
2495 | for (z = pgdat->nr_zones - 1; z >= 0; z--) { | |
bc53008e | 2496 | if (managed_zone(pgdat->node_zones + z)) |
c574bbe9 HY |
2497 | break; |
2498 | } | |
2499 | wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE); | |
340ef390 | 2500 | return 0; |
c574bbe9 | 2501 | } |
7039e1db | 2502 | |
f7f9c00d | 2503 | if (!isolate_lru_page(page)) |
340ef390 | 2504 | return 0; |
7039e1db | 2505 | |
b75454e1 | 2506 | mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page), |
2b9b624f | 2507 | nr_pages); |
340ef390 | 2508 | |
149c33e1 | 2509 | /* |
340ef390 HD |
2510 | * Isolating the page has taken another reference, so the |
2511 | * caller's reference can be safely dropped without the page | |
2512 | * disappearing underneath us during migration. | |
149c33e1 MG |
2513 | */ |
2514 | put_page(page); | |
340ef390 | 2515 | return 1; |
b32967ff MG |
2516 | } |
2517 | ||
2518 | /* | |
2519 | * Attempt to migrate a misplaced page to the specified destination | |
2520 | * node. Caller is expected to have an elevated reference count on | |
2521 | * the page that will be dropped by this function before returning. | |
2522 | */ | |
1bc115d8 MG |
2523 | int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, |
2524 | int node) | |
b32967ff MG |
2525 | { |
2526 | pg_data_t *pgdat = NODE_DATA(node); | |
340ef390 | 2527 | int isolated; |
b32967ff | 2528 | int nr_remaining; |
e39bb6be | 2529 | unsigned int nr_succeeded; |
b32967ff | 2530 | LIST_HEAD(migratepages); |
b5916c02 | 2531 | int nr_pages = thp_nr_pages(page); |
c5b5a3dd | 2532 | |
b32967ff | 2533 | /* |
1bc115d8 MG |
2534 | * Don't migrate file pages that are mapped in multiple processes |
2535 | * with execute permissions as they are probably shared libraries. | |
b32967ff | 2536 | */ |
7ee820ee ML |
2537 | if (page_mapcount(page) != 1 && page_is_file_lru(page) && |
2538 | (vma->vm_flags & VM_EXEC)) | |
b32967ff | 2539 | goto out; |
b32967ff | 2540 | |
09a913a7 MG |
2541 | /* |
2542 | * Also do not migrate dirty pages as not all filesystems can move | |
2543 | * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. | |
2544 | */ | |
9de4f22a | 2545 | if (page_is_file_lru(page) && PageDirty(page)) |
09a913a7 MG |
2546 | goto out; |
2547 | ||
b32967ff MG |
2548 | isolated = numamigrate_isolate_page(pgdat, page); |
2549 | if (!isolated) | |
2550 | goto out; | |
2551 | ||
2552 | list_add(&page->lru, &migratepages); | |
4e096ae1 | 2553 | nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_folio, |
c185e494 MWO |
2554 | NULL, node, MIGRATE_ASYNC, |
2555 | MR_NUMA_MISPLACED, &nr_succeeded); | |
b32967ff | 2556 | if (nr_remaining) { |
59c82b70 JK |
2557 | if (!list_empty(&migratepages)) { |
2558 | list_del(&page->lru); | |
c5fc5c3a YS |
2559 | mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + |
2560 | page_is_file_lru(page), -nr_pages); | |
59c82b70 JK |
2561 | putback_lru_page(page); |
2562 | } | |
b32967ff | 2563 | isolated = 0; |
e39bb6be HY |
2564 | } |
2565 | if (nr_succeeded) { | |
2566 | count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded); | |
2567 | if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node)) | |
2568 | mod_node_page_state(pgdat, PGPROMOTE_SUCCESS, | |
2569 | nr_succeeded); | |
2570 | } | |
7039e1db | 2571 | BUG_ON(!list_empty(&migratepages)); |
7039e1db | 2572 | return isolated; |
340ef390 HD |
2573 | |
2574 | out: | |
2575 | put_page(page); | |
2576 | return 0; | |
7039e1db | 2577 | } |
220018d3 | 2578 | #endif /* CONFIG_NUMA_BALANCING */ |
91952440 | 2579 | #endif /* CONFIG_NUMA */ |