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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
8 | #include <linux/mm.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/highmem.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <linux/mmu_notifier.h> | |
13 | #include <linux/rmap.h> | |
14 | #include <linux/swap.h> | |
97ae1749 | 15 | #include <linux/shrinker.h> |
ba76149f AA |
16 | #include <linux/mm_inline.h> |
17 | #include <linux/kthread.h> | |
18 | #include <linux/khugepaged.h> | |
878aee7d | 19 | #include <linux/freezer.h> |
a664b2d8 | 20 | #include <linux/mman.h> |
325adeb5 | 21 | #include <linux/pagemap.h> |
4daae3b4 | 22 | #include <linux/migrate.h> |
43b5fbbd | 23 | #include <linux/hashtable.h> |
97ae1749 | 24 | |
71e3aac0 AA |
25 | #include <asm/tlb.h> |
26 | #include <asm/pgalloc.h> | |
27 | #include "internal.h" | |
28 | ||
ba76149f AA |
29 | /* |
30 | * By default transparent hugepage support is enabled for all mappings | |
31 | * and khugepaged scans all mappings. Defrag is only invoked by | |
32 | * khugepaged hugepage allocations and by page faults inside | |
33 | * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived | |
34 | * allocations. | |
35 | */ | |
71e3aac0 | 36 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 37 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 38 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
39 | #endif |
40 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
41 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
42 | #endif | |
d39d33c3 | 43 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
79da5407 KS |
44 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
45 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f AA |
46 | |
47 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
48 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
49 | static unsigned int khugepaged_pages_collapsed; | |
50 | static unsigned int khugepaged_full_scans; | |
51 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
52 | /* during fragmentation poll the hugepage allocator once every minute */ | |
53 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
54 | static struct task_struct *khugepaged_thread __read_mostly; | |
55 | static DEFINE_MUTEX(khugepaged_mutex); | |
56 | static DEFINE_SPINLOCK(khugepaged_mm_lock); | |
57 | static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); | |
58 | /* | |
59 | * default collapse hugepages if there is at least one pte mapped like | |
60 | * it would have happened if the vma was large enough during page | |
61 | * fault. | |
62 | */ | |
63 | static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; | |
64 | ||
65 | static int khugepaged(void *none); | |
ba76149f | 66 | static int khugepaged_slab_init(void); |
ba76149f | 67 | |
43b5fbbd SL |
68 | #define MM_SLOTS_HASH_BITS 10 |
69 | static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); | |
70 | ||
ba76149f AA |
71 | static struct kmem_cache *mm_slot_cache __read_mostly; |
72 | ||
73 | /** | |
74 | * struct mm_slot - hash lookup from mm to mm_slot | |
75 | * @hash: hash collision list | |
76 | * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head | |
77 | * @mm: the mm that this information is valid for | |
78 | */ | |
79 | struct mm_slot { | |
80 | struct hlist_node hash; | |
81 | struct list_head mm_node; | |
82 | struct mm_struct *mm; | |
83 | }; | |
84 | ||
85 | /** | |
86 | * struct khugepaged_scan - cursor for scanning | |
87 | * @mm_head: the head of the mm list to scan | |
88 | * @mm_slot: the current mm_slot we are scanning | |
89 | * @address: the next address inside that to be scanned | |
90 | * | |
91 | * There is only the one khugepaged_scan instance of this cursor structure. | |
92 | */ | |
93 | struct khugepaged_scan { | |
94 | struct list_head mm_head; | |
95 | struct mm_slot *mm_slot; | |
96 | unsigned long address; | |
2f1da642 HS |
97 | }; |
98 | static struct khugepaged_scan khugepaged_scan = { | |
ba76149f AA |
99 | .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), |
100 | }; | |
101 | ||
f000565a AA |
102 | |
103 | static int set_recommended_min_free_kbytes(void) | |
104 | { | |
105 | struct zone *zone; | |
106 | int nr_zones = 0; | |
107 | unsigned long recommended_min; | |
108 | extern int min_free_kbytes; | |
109 | ||
17c230af | 110 | if (!khugepaged_enabled()) |
f000565a AA |
111 | return 0; |
112 | ||
113 | for_each_populated_zone(zone) | |
114 | nr_zones++; | |
115 | ||
116 | /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ | |
117 | recommended_min = pageblock_nr_pages * nr_zones * 2; | |
118 | ||
119 | /* | |
120 | * Make sure that on average at least two pageblocks are almost free | |
121 | * of another type, one for a migratetype to fall back to and a | |
122 | * second to avoid subsequent fallbacks of other types There are 3 | |
123 | * MIGRATE_TYPES we care about. | |
124 | */ | |
125 | recommended_min += pageblock_nr_pages * nr_zones * | |
126 | MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; | |
127 | ||
128 | /* don't ever allow to reserve more than 5% of the lowmem */ | |
129 | recommended_min = min(recommended_min, | |
130 | (unsigned long) nr_free_buffer_pages() / 20); | |
131 | recommended_min <<= (PAGE_SHIFT-10); | |
132 | ||
133 | if (recommended_min > min_free_kbytes) | |
134 | min_free_kbytes = recommended_min; | |
135 | setup_per_zone_wmarks(); | |
136 | return 0; | |
137 | } | |
138 | late_initcall(set_recommended_min_free_kbytes); | |
139 | ||
ba76149f AA |
140 | static int start_khugepaged(void) |
141 | { | |
142 | int err = 0; | |
143 | if (khugepaged_enabled()) { | |
ba76149f AA |
144 | if (!khugepaged_thread) |
145 | khugepaged_thread = kthread_run(khugepaged, NULL, | |
146 | "khugepaged"); | |
147 | if (unlikely(IS_ERR(khugepaged_thread))) { | |
148 | printk(KERN_ERR | |
149 | "khugepaged: kthread_run(khugepaged) failed\n"); | |
150 | err = PTR_ERR(khugepaged_thread); | |
151 | khugepaged_thread = NULL; | |
152 | } | |
911891af XG |
153 | |
154 | if (!list_empty(&khugepaged_scan.mm_head)) | |
ba76149f | 155 | wake_up_interruptible(&khugepaged_wait); |
f000565a AA |
156 | |
157 | set_recommended_min_free_kbytes(); | |
911891af | 158 | } else if (khugepaged_thread) { |
911891af XG |
159 | kthread_stop(khugepaged_thread); |
160 | khugepaged_thread = NULL; | |
161 | } | |
637e3a27 | 162 | |
ba76149f AA |
163 | return err; |
164 | } | |
71e3aac0 | 165 | |
97ae1749 KS |
166 | static atomic_t huge_zero_refcount; |
167 | static unsigned long huge_zero_pfn __read_mostly; | |
168 | ||
169 | static inline bool is_huge_zero_pfn(unsigned long pfn) | |
4a6c1297 | 170 | { |
97ae1749 KS |
171 | unsigned long zero_pfn = ACCESS_ONCE(huge_zero_pfn); |
172 | return zero_pfn && pfn == zero_pfn; | |
173 | } | |
4a6c1297 | 174 | |
97ae1749 KS |
175 | static inline bool is_huge_zero_pmd(pmd_t pmd) |
176 | { | |
177 | return is_huge_zero_pfn(pmd_pfn(pmd)); | |
178 | } | |
179 | ||
180 | static unsigned long get_huge_zero_page(void) | |
181 | { | |
182 | struct page *zero_page; | |
183 | retry: | |
184 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
185 | return ACCESS_ONCE(huge_zero_pfn); | |
186 | ||
187 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 188 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
189 | if (!zero_page) { |
190 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
97ae1749 | 191 | return 0; |
d8a8e1f0 KS |
192 | } |
193 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 KS |
194 | preempt_disable(); |
195 | if (cmpxchg(&huge_zero_pfn, 0, page_to_pfn(zero_page))) { | |
196 | preempt_enable(); | |
197 | __free_page(zero_page); | |
198 | goto retry; | |
199 | } | |
200 | ||
201 | /* We take additional reference here. It will be put back by shrinker */ | |
202 | atomic_set(&huge_zero_refcount, 2); | |
203 | preempt_enable(); | |
204 | return ACCESS_ONCE(huge_zero_pfn); | |
4a6c1297 KS |
205 | } |
206 | ||
97ae1749 | 207 | static void put_huge_zero_page(void) |
4a6c1297 | 208 | { |
97ae1749 KS |
209 | /* |
210 | * Counter should never go to zero here. Only shrinker can put | |
211 | * last reference. | |
212 | */ | |
213 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
214 | } |
215 | ||
97ae1749 KS |
216 | static int shrink_huge_zero_page(struct shrinker *shrink, |
217 | struct shrink_control *sc) | |
4a6c1297 | 218 | { |
97ae1749 KS |
219 | if (!sc->nr_to_scan) |
220 | /* we can free zero page only if last reference remains */ | |
221 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
222 | ||
223 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { | |
224 | unsigned long zero_pfn = xchg(&huge_zero_pfn, 0); | |
225 | BUG_ON(zero_pfn == 0); | |
226 | __free_page(__pfn_to_page(zero_pfn)); | |
227 | } | |
228 | ||
229 | return 0; | |
4a6c1297 KS |
230 | } |
231 | ||
97ae1749 KS |
232 | static struct shrinker huge_zero_page_shrinker = { |
233 | .shrink = shrink_huge_zero_page, | |
234 | .seeks = DEFAULT_SEEKS, | |
235 | }; | |
236 | ||
71e3aac0 | 237 | #ifdef CONFIG_SYSFS |
ba76149f | 238 | |
71e3aac0 AA |
239 | static ssize_t double_flag_show(struct kobject *kobj, |
240 | struct kobj_attribute *attr, char *buf, | |
241 | enum transparent_hugepage_flag enabled, | |
242 | enum transparent_hugepage_flag req_madv) | |
243 | { | |
244 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
245 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
246 | return sprintf(buf, "[always] madvise never\n"); | |
247 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
248 | return sprintf(buf, "always [madvise] never\n"); | |
249 | else | |
250 | return sprintf(buf, "always madvise [never]\n"); | |
251 | } | |
252 | static ssize_t double_flag_store(struct kobject *kobj, | |
253 | struct kobj_attribute *attr, | |
254 | const char *buf, size_t count, | |
255 | enum transparent_hugepage_flag enabled, | |
256 | enum transparent_hugepage_flag req_madv) | |
257 | { | |
258 | if (!memcmp("always", buf, | |
259 | min(sizeof("always")-1, count))) { | |
260 | set_bit(enabled, &transparent_hugepage_flags); | |
261 | clear_bit(req_madv, &transparent_hugepage_flags); | |
262 | } else if (!memcmp("madvise", buf, | |
263 | min(sizeof("madvise")-1, count))) { | |
264 | clear_bit(enabled, &transparent_hugepage_flags); | |
265 | set_bit(req_madv, &transparent_hugepage_flags); | |
266 | } else if (!memcmp("never", buf, | |
267 | min(sizeof("never")-1, count))) { | |
268 | clear_bit(enabled, &transparent_hugepage_flags); | |
269 | clear_bit(req_madv, &transparent_hugepage_flags); | |
270 | } else | |
271 | return -EINVAL; | |
272 | ||
273 | return count; | |
274 | } | |
275 | ||
276 | static ssize_t enabled_show(struct kobject *kobj, | |
277 | struct kobj_attribute *attr, char *buf) | |
278 | { | |
279 | return double_flag_show(kobj, attr, buf, | |
280 | TRANSPARENT_HUGEPAGE_FLAG, | |
281 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
282 | } | |
283 | static ssize_t enabled_store(struct kobject *kobj, | |
284 | struct kobj_attribute *attr, | |
285 | const char *buf, size_t count) | |
286 | { | |
ba76149f AA |
287 | ssize_t ret; |
288 | ||
289 | ret = double_flag_store(kobj, attr, buf, count, | |
290 | TRANSPARENT_HUGEPAGE_FLAG, | |
291 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
292 | ||
293 | if (ret > 0) { | |
911891af XG |
294 | int err; |
295 | ||
296 | mutex_lock(&khugepaged_mutex); | |
297 | err = start_khugepaged(); | |
298 | mutex_unlock(&khugepaged_mutex); | |
299 | ||
ba76149f AA |
300 | if (err) |
301 | ret = err; | |
302 | } | |
303 | ||
304 | return ret; | |
71e3aac0 AA |
305 | } |
306 | static struct kobj_attribute enabled_attr = | |
307 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
308 | ||
309 | static ssize_t single_flag_show(struct kobject *kobj, | |
310 | struct kobj_attribute *attr, char *buf, | |
311 | enum transparent_hugepage_flag flag) | |
312 | { | |
e27e6151 BH |
313 | return sprintf(buf, "%d\n", |
314 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 315 | } |
e27e6151 | 316 | |
71e3aac0 AA |
317 | static ssize_t single_flag_store(struct kobject *kobj, |
318 | struct kobj_attribute *attr, | |
319 | const char *buf, size_t count, | |
320 | enum transparent_hugepage_flag flag) | |
321 | { | |
e27e6151 BH |
322 | unsigned long value; |
323 | int ret; | |
324 | ||
325 | ret = kstrtoul(buf, 10, &value); | |
326 | if (ret < 0) | |
327 | return ret; | |
328 | if (value > 1) | |
329 | return -EINVAL; | |
330 | ||
331 | if (value) | |
71e3aac0 | 332 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 333 | else |
71e3aac0 | 334 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
335 | |
336 | return count; | |
337 | } | |
338 | ||
339 | /* | |
340 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
341 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
342 | * memory just to allocate one more hugepage. | |
343 | */ | |
344 | static ssize_t defrag_show(struct kobject *kobj, | |
345 | struct kobj_attribute *attr, char *buf) | |
346 | { | |
347 | return double_flag_show(kobj, attr, buf, | |
348 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
349 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
350 | } | |
351 | static ssize_t defrag_store(struct kobject *kobj, | |
352 | struct kobj_attribute *attr, | |
353 | const char *buf, size_t count) | |
354 | { | |
355 | return double_flag_store(kobj, attr, buf, count, | |
356 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
357 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
358 | } | |
359 | static struct kobj_attribute defrag_attr = | |
360 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
361 | ||
79da5407 KS |
362 | static ssize_t use_zero_page_show(struct kobject *kobj, |
363 | struct kobj_attribute *attr, char *buf) | |
364 | { | |
365 | return single_flag_show(kobj, attr, buf, | |
366 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
367 | } | |
368 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
369 | struct kobj_attribute *attr, const char *buf, size_t count) | |
370 | { | |
371 | return single_flag_store(kobj, attr, buf, count, | |
372 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
373 | } | |
374 | static struct kobj_attribute use_zero_page_attr = | |
375 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
71e3aac0 AA |
376 | #ifdef CONFIG_DEBUG_VM |
377 | static ssize_t debug_cow_show(struct kobject *kobj, | |
378 | struct kobj_attribute *attr, char *buf) | |
379 | { | |
380 | return single_flag_show(kobj, attr, buf, | |
381 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
382 | } | |
383 | static ssize_t debug_cow_store(struct kobject *kobj, | |
384 | struct kobj_attribute *attr, | |
385 | const char *buf, size_t count) | |
386 | { | |
387 | return single_flag_store(kobj, attr, buf, count, | |
388 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
389 | } | |
390 | static struct kobj_attribute debug_cow_attr = | |
391 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
392 | #endif /* CONFIG_DEBUG_VM */ | |
393 | ||
394 | static struct attribute *hugepage_attr[] = { | |
395 | &enabled_attr.attr, | |
396 | &defrag_attr.attr, | |
79da5407 | 397 | &use_zero_page_attr.attr, |
71e3aac0 AA |
398 | #ifdef CONFIG_DEBUG_VM |
399 | &debug_cow_attr.attr, | |
400 | #endif | |
401 | NULL, | |
402 | }; | |
403 | ||
404 | static struct attribute_group hugepage_attr_group = { | |
405 | .attrs = hugepage_attr, | |
ba76149f AA |
406 | }; |
407 | ||
408 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
409 | struct kobj_attribute *attr, | |
410 | char *buf) | |
411 | { | |
412 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
413 | } | |
414 | ||
415 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
416 | struct kobj_attribute *attr, | |
417 | const char *buf, size_t count) | |
418 | { | |
419 | unsigned long msecs; | |
420 | int err; | |
421 | ||
422 | err = strict_strtoul(buf, 10, &msecs); | |
423 | if (err || msecs > UINT_MAX) | |
424 | return -EINVAL; | |
425 | ||
426 | khugepaged_scan_sleep_millisecs = msecs; | |
427 | wake_up_interruptible(&khugepaged_wait); | |
428 | ||
429 | return count; | |
430 | } | |
431 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
432 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
433 | scan_sleep_millisecs_store); | |
434 | ||
435 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
436 | struct kobj_attribute *attr, | |
437 | char *buf) | |
438 | { | |
439 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
440 | } | |
441 | ||
442 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
443 | struct kobj_attribute *attr, | |
444 | const char *buf, size_t count) | |
445 | { | |
446 | unsigned long msecs; | |
447 | int err; | |
448 | ||
449 | err = strict_strtoul(buf, 10, &msecs); | |
450 | if (err || msecs > UINT_MAX) | |
451 | return -EINVAL; | |
452 | ||
453 | khugepaged_alloc_sleep_millisecs = msecs; | |
454 | wake_up_interruptible(&khugepaged_wait); | |
455 | ||
456 | return count; | |
457 | } | |
458 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
459 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
460 | alloc_sleep_millisecs_store); | |
461 | ||
462 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
463 | struct kobj_attribute *attr, | |
464 | char *buf) | |
465 | { | |
466 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
467 | } | |
468 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
469 | struct kobj_attribute *attr, | |
470 | const char *buf, size_t count) | |
471 | { | |
472 | int err; | |
473 | unsigned long pages; | |
474 | ||
475 | err = strict_strtoul(buf, 10, &pages); | |
476 | if (err || !pages || pages > UINT_MAX) | |
477 | return -EINVAL; | |
478 | ||
479 | khugepaged_pages_to_scan = pages; | |
480 | ||
481 | return count; | |
482 | } | |
483 | static struct kobj_attribute pages_to_scan_attr = | |
484 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
485 | pages_to_scan_store); | |
486 | ||
487 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
488 | struct kobj_attribute *attr, | |
489 | char *buf) | |
490 | { | |
491 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
492 | } | |
493 | static struct kobj_attribute pages_collapsed_attr = | |
494 | __ATTR_RO(pages_collapsed); | |
495 | ||
496 | static ssize_t full_scans_show(struct kobject *kobj, | |
497 | struct kobj_attribute *attr, | |
498 | char *buf) | |
499 | { | |
500 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
501 | } | |
502 | static struct kobj_attribute full_scans_attr = | |
503 | __ATTR_RO(full_scans); | |
504 | ||
505 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
506 | struct kobj_attribute *attr, char *buf) | |
507 | { | |
508 | return single_flag_show(kobj, attr, buf, | |
509 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
510 | } | |
511 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
512 | struct kobj_attribute *attr, | |
513 | const char *buf, size_t count) | |
514 | { | |
515 | return single_flag_store(kobj, attr, buf, count, | |
516 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
517 | } | |
518 | static struct kobj_attribute khugepaged_defrag_attr = | |
519 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
520 | khugepaged_defrag_store); | |
521 | ||
522 | /* | |
523 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
524 | * any unmapped ptes in turn potentially increasing the memory | |
525 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
526 | * reduce the available free memory in the system as it | |
527 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
528 | * free memory in the system during the khugepaged scan. | |
529 | */ | |
530 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
531 | struct kobj_attribute *attr, | |
532 | char *buf) | |
533 | { | |
534 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
535 | } | |
536 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
537 | struct kobj_attribute *attr, | |
538 | const char *buf, size_t count) | |
539 | { | |
540 | int err; | |
541 | unsigned long max_ptes_none; | |
542 | ||
543 | err = strict_strtoul(buf, 10, &max_ptes_none); | |
544 | if (err || max_ptes_none > HPAGE_PMD_NR-1) | |
545 | return -EINVAL; | |
546 | ||
547 | khugepaged_max_ptes_none = max_ptes_none; | |
548 | ||
549 | return count; | |
550 | } | |
551 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
552 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
553 | khugepaged_max_ptes_none_store); | |
554 | ||
555 | static struct attribute *khugepaged_attr[] = { | |
556 | &khugepaged_defrag_attr.attr, | |
557 | &khugepaged_max_ptes_none_attr.attr, | |
558 | &pages_to_scan_attr.attr, | |
559 | &pages_collapsed_attr.attr, | |
560 | &full_scans_attr.attr, | |
561 | &scan_sleep_millisecs_attr.attr, | |
562 | &alloc_sleep_millisecs_attr.attr, | |
563 | NULL, | |
564 | }; | |
565 | ||
566 | static struct attribute_group khugepaged_attr_group = { | |
567 | .attrs = khugepaged_attr, | |
568 | .name = "khugepaged", | |
71e3aac0 | 569 | }; |
71e3aac0 | 570 | |
569e5590 | 571 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 572 | { |
71e3aac0 AA |
573 | int err; |
574 | ||
569e5590 SL |
575 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
576 | if (unlikely(!*hugepage_kobj)) { | |
2c79737a | 577 | printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n"); |
569e5590 | 578 | return -ENOMEM; |
ba76149f AA |
579 | } |
580 | ||
569e5590 | 581 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 582 | if (err) { |
2c79737a | 583 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 584 | goto delete_obj; |
ba76149f AA |
585 | } |
586 | ||
569e5590 | 587 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 588 | if (err) { |
2c79737a | 589 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 590 | goto remove_hp_group; |
ba76149f | 591 | } |
569e5590 SL |
592 | |
593 | return 0; | |
594 | ||
595 | remove_hp_group: | |
596 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
597 | delete_obj: | |
598 | kobject_put(*hugepage_kobj); | |
599 | return err; | |
600 | } | |
601 | ||
602 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
603 | { | |
604 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
605 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
606 | kobject_put(hugepage_kobj); | |
607 | } | |
608 | #else | |
609 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
610 | { | |
611 | return 0; | |
612 | } | |
613 | ||
614 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
615 | { | |
616 | } | |
617 | #endif /* CONFIG_SYSFS */ | |
618 | ||
619 | static int __init hugepage_init(void) | |
620 | { | |
621 | int err; | |
622 | struct kobject *hugepage_kobj; | |
623 | ||
624 | if (!has_transparent_hugepage()) { | |
625 | transparent_hugepage_flags = 0; | |
626 | return -EINVAL; | |
627 | } | |
628 | ||
629 | err = hugepage_init_sysfs(&hugepage_kobj); | |
630 | if (err) | |
631 | return err; | |
ba76149f AA |
632 | |
633 | err = khugepaged_slab_init(); | |
634 | if (err) | |
635 | goto out; | |
636 | ||
97ae1749 KS |
637 | register_shrinker(&huge_zero_page_shrinker); |
638 | ||
97562cd2 RR |
639 | /* |
640 | * By default disable transparent hugepages on smaller systems, | |
641 | * where the extra memory used could hurt more than TLB overhead | |
642 | * is likely to save. The admin can still enable it through /sys. | |
643 | */ | |
644 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
645 | transparent_hugepage_flags = 0; | |
646 | ||
ba76149f AA |
647 | start_khugepaged(); |
648 | ||
569e5590 | 649 | return 0; |
ba76149f | 650 | out: |
569e5590 | 651 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 652 | return err; |
71e3aac0 AA |
653 | } |
654 | module_init(hugepage_init) | |
655 | ||
656 | static int __init setup_transparent_hugepage(char *str) | |
657 | { | |
658 | int ret = 0; | |
659 | if (!str) | |
660 | goto out; | |
661 | if (!strcmp(str, "always")) { | |
662 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
663 | &transparent_hugepage_flags); | |
664 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
665 | &transparent_hugepage_flags); | |
666 | ret = 1; | |
667 | } else if (!strcmp(str, "madvise")) { | |
668 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
669 | &transparent_hugepage_flags); | |
670 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
671 | &transparent_hugepage_flags); | |
672 | ret = 1; | |
673 | } else if (!strcmp(str, "never")) { | |
674 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
675 | &transparent_hugepage_flags); | |
676 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
677 | &transparent_hugepage_flags); | |
678 | ret = 1; | |
679 | } | |
680 | out: | |
681 | if (!ret) | |
682 | printk(KERN_WARNING | |
683 | "transparent_hugepage= cannot parse, ignored\n"); | |
684 | return ret; | |
685 | } | |
686 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
687 | ||
b32967ff | 688 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
689 | { |
690 | if (likely(vma->vm_flags & VM_WRITE)) | |
691 | pmd = pmd_mkwrite(pmd); | |
692 | return pmd; | |
693 | } | |
694 | ||
b3092b3b BL |
695 | static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma) |
696 | { | |
697 | pmd_t entry; | |
698 | entry = mk_pmd(page, vma->vm_page_prot); | |
699 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
700 | entry = pmd_mkhuge(entry); | |
701 | return entry; | |
702 | } | |
703 | ||
71e3aac0 AA |
704 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
705 | struct vm_area_struct *vma, | |
706 | unsigned long haddr, pmd_t *pmd, | |
707 | struct page *page) | |
708 | { | |
71e3aac0 AA |
709 | pgtable_t pgtable; |
710 | ||
711 | VM_BUG_ON(!PageCompound(page)); | |
712 | pgtable = pte_alloc_one(mm, haddr); | |
edad9d2c | 713 | if (unlikely(!pgtable)) |
71e3aac0 | 714 | return VM_FAULT_OOM; |
71e3aac0 AA |
715 | |
716 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
717 | __SetPageUptodate(page); | |
718 | ||
719 | spin_lock(&mm->page_table_lock); | |
720 | if (unlikely(!pmd_none(*pmd))) { | |
721 | spin_unlock(&mm->page_table_lock); | |
b9bbfbe3 | 722 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
723 | put_page(page); |
724 | pte_free(mm, pgtable); | |
725 | } else { | |
726 | pmd_t entry; | |
b3092b3b | 727 | entry = mk_huge_pmd(page, vma); |
71e3aac0 AA |
728 | /* |
729 | * The spinlocking to take the lru_lock inside | |
730 | * page_add_new_anon_rmap() acts as a full memory | |
731 | * barrier to be sure clear_huge_page writes become | |
732 | * visible after the set_pmd_at() write. | |
733 | */ | |
734 | page_add_new_anon_rmap(page, vma, haddr); | |
735 | set_pmd_at(mm, haddr, pmd, entry); | |
e3ebcf64 | 736 | pgtable_trans_huge_deposit(mm, pgtable); |
71e3aac0 | 737 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
1c641e84 | 738 | mm->nr_ptes++; |
71e3aac0 AA |
739 | spin_unlock(&mm->page_table_lock); |
740 | } | |
741 | ||
aa2e878e | 742 | return 0; |
71e3aac0 AA |
743 | } |
744 | ||
cc5d462f | 745 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 746 | { |
cc5d462f | 747 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
748 | } |
749 | ||
750 | static inline struct page *alloc_hugepage_vma(int defrag, | |
751 | struct vm_area_struct *vma, | |
cc5d462f AK |
752 | unsigned long haddr, int nd, |
753 | gfp_t extra_gfp) | |
0bbbc0b3 | 754 | { |
cc5d462f | 755 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 756 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
757 | } |
758 | ||
759 | #ifndef CONFIG_NUMA | |
71e3aac0 AA |
760 | static inline struct page *alloc_hugepage(int defrag) |
761 | { | |
cc5d462f | 762 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), |
71e3aac0 AA |
763 | HPAGE_PMD_ORDER); |
764 | } | |
0bbbc0b3 | 765 | #endif |
71e3aac0 | 766 | |
3ea41e62 | 767 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 KS |
768 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
769 | unsigned long zero_pfn) | |
fc9fe822 KS |
770 | { |
771 | pmd_t entry; | |
3ea41e62 KS |
772 | if (!pmd_none(*pmd)) |
773 | return false; | |
97ae1749 | 774 | entry = pfn_pmd(zero_pfn, vma->vm_page_prot); |
fc9fe822 KS |
775 | entry = pmd_wrprotect(entry); |
776 | entry = pmd_mkhuge(entry); | |
777 | set_pmd_at(mm, haddr, pmd, entry); | |
778 | pgtable_trans_huge_deposit(mm, pgtable); | |
779 | mm->nr_ptes++; | |
3ea41e62 | 780 | return true; |
fc9fe822 KS |
781 | } |
782 | ||
71e3aac0 AA |
783 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
784 | unsigned long address, pmd_t *pmd, | |
785 | unsigned int flags) | |
786 | { | |
787 | struct page *page; | |
788 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
789 | pte_t *pte; | |
790 | ||
791 | if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { | |
792 | if (unlikely(anon_vma_prepare(vma))) | |
793 | return VM_FAULT_OOM; | |
ba76149f AA |
794 | if (unlikely(khugepaged_enter(vma))) |
795 | return VM_FAULT_OOM; | |
79da5407 KS |
796 | if (!(flags & FAULT_FLAG_WRITE) && |
797 | transparent_hugepage_use_zero_page()) { | |
80371957 | 798 | pgtable_t pgtable; |
97ae1749 | 799 | unsigned long zero_pfn; |
3ea41e62 | 800 | bool set; |
80371957 KS |
801 | pgtable = pte_alloc_one(mm, haddr); |
802 | if (unlikely(!pgtable)) | |
803 | return VM_FAULT_OOM; | |
97ae1749 KS |
804 | zero_pfn = get_huge_zero_page(); |
805 | if (unlikely(!zero_pfn)) { | |
806 | pte_free(mm, pgtable); | |
807 | count_vm_event(THP_FAULT_FALLBACK); | |
808 | goto out; | |
809 | } | |
80371957 | 810 | spin_lock(&mm->page_table_lock); |
3ea41e62 | 811 | set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, |
97ae1749 | 812 | zero_pfn); |
80371957 | 813 | spin_unlock(&mm->page_table_lock); |
3ea41e62 KS |
814 | if (!set) { |
815 | pte_free(mm, pgtable); | |
816 | put_huge_zero_page(); | |
817 | } | |
80371957 KS |
818 | return 0; |
819 | } | |
0bbbc0b3 | 820 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 821 | vma, haddr, numa_node_id(), 0); |
81ab4201 AK |
822 | if (unlikely(!page)) { |
823 | count_vm_event(THP_FAULT_FALLBACK); | |
71e3aac0 | 824 | goto out; |
81ab4201 AK |
825 | } |
826 | count_vm_event(THP_FAULT_ALLOC); | |
b9bbfbe3 AA |
827 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
828 | put_page(page); | |
829 | goto out; | |
830 | } | |
edad9d2c DR |
831 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, |
832 | page))) { | |
833 | mem_cgroup_uncharge_page(page); | |
834 | put_page(page); | |
835 | goto out; | |
836 | } | |
71e3aac0 | 837 | |
edad9d2c | 838 | return 0; |
71e3aac0 AA |
839 | } |
840 | out: | |
841 | /* | |
842 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
843 | * run pte_offset_map on the pmd, if an huge pmd could | |
844 | * materialize from under us from a different thread. | |
845 | */ | |
4fd01770 MG |
846 | if (unlikely(pmd_none(*pmd)) && |
847 | unlikely(__pte_alloc(mm, vma, pmd, address))) | |
71e3aac0 AA |
848 | return VM_FAULT_OOM; |
849 | /* if an huge pmd materialized from under us just retry later */ | |
850 | if (unlikely(pmd_trans_huge(*pmd))) | |
851 | return 0; | |
852 | /* | |
853 | * A regular pmd is established and it can't morph into a huge pmd | |
854 | * from under us anymore at this point because we hold the mmap_sem | |
855 | * read mode and khugepaged takes it in write mode. So now it's | |
856 | * safe to run pte_offset_map(). | |
857 | */ | |
858 | pte = pte_offset_map(pmd, address); | |
859 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); | |
860 | } | |
861 | ||
862 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
863 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
864 | struct vm_area_struct *vma) | |
865 | { | |
866 | struct page *src_page; | |
867 | pmd_t pmd; | |
868 | pgtable_t pgtable; | |
869 | int ret; | |
870 | ||
871 | ret = -ENOMEM; | |
872 | pgtable = pte_alloc_one(dst_mm, addr); | |
873 | if (unlikely(!pgtable)) | |
874 | goto out; | |
875 | ||
876 | spin_lock(&dst_mm->page_table_lock); | |
877 | spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); | |
878 | ||
879 | ret = -EAGAIN; | |
880 | pmd = *src_pmd; | |
881 | if (unlikely(!pmd_trans_huge(pmd))) { | |
882 | pte_free(dst_mm, pgtable); | |
883 | goto out_unlock; | |
884 | } | |
fc9fe822 KS |
885 | /* |
886 | * mm->page_table_lock is enough to be sure that huge zero pmd is not | |
887 | * under splitting since we don't split the page itself, only pmd to | |
888 | * a page table. | |
889 | */ | |
890 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 | 891 | unsigned long zero_pfn; |
3ea41e62 | 892 | bool set; |
97ae1749 KS |
893 | /* |
894 | * get_huge_zero_page() will never allocate a new page here, | |
895 | * since we already have a zero page to copy. It just takes a | |
896 | * reference. | |
897 | */ | |
898 | zero_pfn = get_huge_zero_page(); | |
3ea41e62 | 899 | set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
97ae1749 | 900 | zero_pfn); |
3ea41e62 | 901 | BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ |
fc9fe822 KS |
902 | ret = 0; |
903 | goto out_unlock; | |
904 | } | |
71e3aac0 AA |
905 | if (unlikely(pmd_trans_splitting(pmd))) { |
906 | /* split huge page running from under us */ | |
907 | spin_unlock(&src_mm->page_table_lock); | |
908 | spin_unlock(&dst_mm->page_table_lock); | |
909 | pte_free(dst_mm, pgtable); | |
910 | ||
911 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
912 | goto out; | |
913 | } | |
914 | src_page = pmd_page(pmd); | |
915 | VM_BUG_ON(!PageHead(src_page)); | |
916 | get_page(src_page); | |
917 | page_dup_rmap(src_page); | |
918 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
919 | ||
920 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
921 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
922 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
e3ebcf64 | 923 | pgtable_trans_huge_deposit(dst_mm, pgtable); |
1c641e84 | 924 | dst_mm->nr_ptes++; |
71e3aac0 AA |
925 | |
926 | ret = 0; | |
927 | out_unlock: | |
928 | spin_unlock(&src_mm->page_table_lock); | |
929 | spin_unlock(&dst_mm->page_table_lock); | |
930 | out: | |
931 | return ret; | |
932 | } | |
933 | ||
a1dd450b WD |
934 | void huge_pmd_set_accessed(struct mm_struct *mm, |
935 | struct vm_area_struct *vma, | |
936 | unsigned long address, | |
937 | pmd_t *pmd, pmd_t orig_pmd, | |
938 | int dirty) | |
939 | { | |
940 | pmd_t entry; | |
941 | unsigned long haddr; | |
942 | ||
943 | spin_lock(&mm->page_table_lock); | |
944 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
945 | goto unlock; | |
946 | ||
947 | entry = pmd_mkyoung(orig_pmd); | |
948 | haddr = address & HPAGE_PMD_MASK; | |
949 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
950 | update_mmu_cache_pmd(vma, address, pmd); | |
951 | ||
952 | unlock: | |
953 | spin_unlock(&mm->page_table_lock); | |
954 | } | |
955 | ||
93b4796d KS |
956 | static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, |
957 | struct vm_area_struct *vma, unsigned long address, | |
3ea41e62 | 958 | pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr) |
93b4796d KS |
959 | { |
960 | pgtable_t pgtable; | |
961 | pmd_t _pmd; | |
962 | struct page *page; | |
963 | int i, ret = 0; | |
964 | unsigned long mmun_start; /* For mmu_notifiers */ | |
965 | unsigned long mmun_end; /* For mmu_notifiers */ | |
966 | ||
967 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
968 | if (!page) { | |
969 | ret |= VM_FAULT_OOM; | |
970 | goto out; | |
971 | } | |
972 | ||
973 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { | |
974 | put_page(page); | |
975 | ret |= VM_FAULT_OOM; | |
976 | goto out; | |
977 | } | |
978 | ||
979 | clear_user_highpage(page, address); | |
980 | __SetPageUptodate(page); | |
981 | ||
982 | mmun_start = haddr; | |
983 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
984 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
985 | ||
986 | spin_lock(&mm->page_table_lock); | |
3ea41e62 KS |
987 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
988 | goto out_free_page; | |
989 | ||
93b4796d KS |
990 | pmdp_clear_flush(vma, haddr, pmd); |
991 | /* leave pmd empty until pte is filled */ | |
992 | ||
993 | pgtable = pgtable_trans_huge_withdraw(mm); | |
994 | pmd_populate(mm, &_pmd, pgtable); | |
995 | ||
996 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
997 | pte_t *pte, entry; | |
998 | if (haddr == (address & PAGE_MASK)) { | |
999 | entry = mk_pte(page, vma->vm_page_prot); | |
1000 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1001 | page_add_new_anon_rmap(page, vma, haddr); | |
1002 | } else { | |
1003 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1004 | entry = pte_mkspecial(entry); | |
1005 | } | |
1006 | pte = pte_offset_map(&_pmd, haddr); | |
1007 | VM_BUG_ON(!pte_none(*pte)); | |
1008 | set_pte_at(mm, haddr, pte, entry); | |
1009 | pte_unmap(pte); | |
1010 | } | |
1011 | smp_wmb(); /* make pte visible before pmd */ | |
1012 | pmd_populate(mm, pmd, pgtable); | |
1013 | spin_unlock(&mm->page_table_lock); | |
97ae1749 | 1014 | put_huge_zero_page(); |
93b4796d KS |
1015 | inc_mm_counter(mm, MM_ANONPAGES); |
1016 | ||
1017 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1018 | ||
1019 | ret |= VM_FAULT_WRITE; | |
1020 | out: | |
1021 | return ret; | |
3ea41e62 KS |
1022 | out_free_page: |
1023 | spin_unlock(&mm->page_table_lock); | |
1024 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1025 | mem_cgroup_uncharge_page(page); | |
1026 | put_page(page); | |
1027 | goto out; | |
93b4796d KS |
1028 | } |
1029 | ||
71e3aac0 AA |
1030 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
1031 | struct vm_area_struct *vma, | |
1032 | unsigned long address, | |
1033 | pmd_t *pmd, pmd_t orig_pmd, | |
1034 | struct page *page, | |
1035 | unsigned long haddr) | |
1036 | { | |
1037 | pgtable_t pgtable; | |
1038 | pmd_t _pmd; | |
1039 | int ret = 0, i; | |
1040 | struct page **pages; | |
2ec74c3e SG |
1041 | unsigned long mmun_start; /* For mmu_notifiers */ |
1042 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1043 | |
1044 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1045 | GFP_KERNEL); | |
1046 | if (unlikely(!pages)) { | |
1047 | ret |= VM_FAULT_OOM; | |
1048 | goto out; | |
1049 | } | |
1050 | ||
1051 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
1052 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
1053 | __GFP_OTHER_NODE, | |
19ee151e | 1054 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
1055 | if (unlikely(!pages[i] || |
1056 | mem_cgroup_newpage_charge(pages[i], mm, | |
1057 | GFP_KERNEL))) { | |
1058 | if (pages[i]) | |
71e3aac0 | 1059 | put_page(pages[i]); |
b9bbfbe3 AA |
1060 | mem_cgroup_uncharge_start(); |
1061 | while (--i >= 0) { | |
1062 | mem_cgroup_uncharge_page(pages[i]); | |
1063 | put_page(pages[i]); | |
1064 | } | |
1065 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1066 | kfree(pages); |
1067 | ret |= VM_FAULT_OOM; | |
1068 | goto out; | |
1069 | } | |
1070 | } | |
1071 | ||
1072 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1073 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1074 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1075 | __SetPageUptodate(pages[i]); |
1076 | cond_resched(); | |
1077 | } | |
1078 | ||
2ec74c3e SG |
1079 | mmun_start = haddr; |
1080 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1081 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1082 | ||
71e3aac0 AA |
1083 | spin_lock(&mm->page_table_lock); |
1084 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1085 | goto out_free_pages; | |
1086 | VM_BUG_ON(!PageHead(page)); | |
1087 | ||
2ec74c3e | 1088 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1089 | /* leave pmd empty until pte is filled */ |
1090 | ||
e3ebcf64 | 1091 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1092 | pmd_populate(mm, &_pmd, pgtable); |
1093 | ||
1094 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1095 | pte_t *pte, entry; | |
1096 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
1097 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1098 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
1099 | pte = pte_offset_map(&_pmd, haddr); | |
1100 | VM_BUG_ON(!pte_none(*pte)); | |
1101 | set_pte_at(mm, haddr, pte, entry); | |
1102 | pte_unmap(pte); | |
1103 | } | |
1104 | kfree(pages); | |
1105 | ||
71e3aac0 AA |
1106 | smp_wmb(); /* make pte visible before pmd */ |
1107 | pmd_populate(mm, pmd, pgtable); | |
1108 | page_remove_rmap(page); | |
1109 | spin_unlock(&mm->page_table_lock); | |
1110 | ||
2ec74c3e SG |
1111 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1112 | ||
71e3aac0 AA |
1113 | ret |= VM_FAULT_WRITE; |
1114 | put_page(page); | |
1115 | ||
1116 | out: | |
1117 | return ret; | |
1118 | ||
1119 | out_free_pages: | |
1120 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1121 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1122 | mem_cgroup_uncharge_start(); |
1123 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1124 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1125 | put_page(pages[i]); |
b9bbfbe3 AA |
1126 | } |
1127 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1128 | kfree(pages); |
1129 | goto out; | |
1130 | } | |
1131 | ||
1132 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1133 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1134 | { | |
1135 | int ret = 0; | |
93b4796d | 1136 | struct page *page = NULL, *new_page; |
71e3aac0 | 1137 | unsigned long haddr; |
2ec74c3e SG |
1138 | unsigned long mmun_start; /* For mmu_notifiers */ |
1139 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1140 | |
1141 | VM_BUG_ON(!vma->anon_vma); | |
93b4796d KS |
1142 | haddr = address & HPAGE_PMD_MASK; |
1143 | if (is_huge_zero_pmd(orig_pmd)) | |
1144 | goto alloc; | |
71e3aac0 AA |
1145 | spin_lock(&mm->page_table_lock); |
1146 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1147 | goto out_unlock; | |
1148 | ||
1149 | page = pmd_page(orig_pmd); | |
1150 | VM_BUG_ON(!PageCompound(page) || !PageHead(page)); | |
71e3aac0 AA |
1151 | if (page_mapcount(page) == 1) { |
1152 | pmd_t entry; | |
1153 | entry = pmd_mkyoung(orig_pmd); | |
1154 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1155 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1156 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1157 | ret |= VM_FAULT_WRITE; |
1158 | goto out_unlock; | |
1159 | } | |
1160 | get_page(page); | |
1161 | spin_unlock(&mm->page_table_lock); | |
93b4796d | 1162 | alloc: |
71e3aac0 AA |
1163 | if (transparent_hugepage_enabled(vma) && |
1164 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1165 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1166 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1167 | else |
1168 | new_page = NULL; | |
1169 | ||
1170 | if (unlikely(!new_page)) { | |
81ab4201 | 1171 | count_vm_event(THP_FAULT_FALLBACK); |
93b4796d KS |
1172 | if (is_huge_zero_pmd(orig_pmd)) { |
1173 | ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, | |
3ea41e62 | 1174 | address, pmd, orig_pmd, haddr); |
93b4796d KS |
1175 | } else { |
1176 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1177 | pmd, orig_pmd, page, haddr); | |
1178 | if (ret & VM_FAULT_OOM) | |
1179 | split_huge_page(page); | |
1180 | put_page(page); | |
1181 | } | |
71e3aac0 AA |
1182 | goto out; |
1183 | } | |
81ab4201 | 1184 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 | 1185 | |
b9bbfbe3 AA |
1186 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1187 | put_page(new_page); | |
93b4796d KS |
1188 | if (page) { |
1189 | split_huge_page(page); | |
1190 | put_page(page); | |
1191 | } | |
b9bbfbe3 AA |
1192 | ret |= VM_FAULT_OOM; |
1193 | goto out; | |
1194 | } | |
1195 | ||
93b4796d KS |
1196 | if (is_huge_zero_pmd(orig_pmd)) |
1197 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); | |
1198 | else | |
1199 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1200 | __SetPageUptodate(new_page); |
1201 | ||
2ec74c3e SG |
1202 | mmun_start = haddr; |
1203 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1204 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1205 | ||
71e3aac0 | 1206 | spin_lock(&mm->page_table_lock); |
93b4796d KS |
1207 | if (page) |
1208 | put_page(page); | |
b9bbfbe3 | 1209 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
6f60b69d | 1210 | spin_unlock(&mm->page_table_lock); |
b9bbfbe3 | 1211 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1212 | put_page(new_page); |
2ec74c3e | 1213 | goto out_mn; |
b9bbfbe3 | 1214 | } else { |
71e3aac0 | 1215 | pmd_t entry; |
b3092b3b | 1216 | entry = mk_huge_pmd(new_page, vma); |
2ec74c3e | 1217 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1218 | page_add_new_anon_rmap(new_page, vma, haddr); |
1219 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1220 | update_mmu_cache_pmd(vma, address, pmd); |
97ae1749 | 1221 | if (is_huge_zero_pmd(orig_pmd)) { |
93b4796d | 1222 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 KS |
1223 | put_huge_zero_page(); |
1224 | } else { | |
93b4796d KS |
1225 | VM_BUG_ON(!PageHead(page)); |
1226 | page_remove_rmap(page); | |
1227 | put_page(page); | |
1228 | } | |
71e3aac0 AA |
1229 | ret |= VM_FAULT_WRITE; |
1230 | } | |
71e3aac0 | 1231 | spin_unlock(&mm->page_table_lock); |
2ec74c3e SG |
1232 | out_mn: |
1233 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1234 | out: |
1235 | return ret; | |
2ec74c3e SG |
1236 | out_unlock: |
1237 | spin_unlock(&mm->page_table_lock); | |
1238 | return ret; | |
71e3aac0 AA |
1239 | } |
1240 | ||
b676b293 | 1241 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1242 | unsigned long addr, |
1243 | pmd_t *pmd, | |
1244 | unsigned int flags) | |
1245 | { | |
b676b293 | 1246 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1247 | struct page *page = NULL; |
1248 | ||
1249 | assert_spin_locked(&mm->page_table_lock); | |
1250 | ||
1251 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1252 | goto out; | |
1253 | ||
85facf25 KS |
1254 | /* Avoid dumping huge zero page */ |
1255 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1256 | return ERR_PTR(-EFAULT); | |
1257 | ||
71e3aac0 AA |
1258 | page = pmd_page(*pmd); |
1259 | VM_BUG_ON(!PageHead(page)); | |
1260 | if (flags & FOLL_TOUCH) { | |
1261 | pmd_t _pmd; | |
1262 | /* | |
1263 | * We should set the dirty bit only for FOLL_WRITE but | |
1264 | * for now the dirty bit in the pmd is meaningless. | |
1265 | * And if the dirty bit will become meaningful and | |
1266 | * we'll only set it with FOLL_WRITE, an atomic | |
1267 | * set_bit will be required on the pmd to set the | |
1268 | * young bit, instead of the current set_pmd_at. | |
1269 | */ | |
1270 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
1271 | set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); | |
1272 | } | |
b676b293 DR |
1273 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1274 | if (page->mapping && trylock_page(page)) { | |
1275 | lru_add_drain(); | |
1276 | if (page->mapping) | |
1277 | mlock_vma_page(page); | |
1278 | unlock_page(page); | |
1279 | } | |
1280 | } | |
71e3aac0 AA |
1281 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
1282 | VM_BUG_ON(!PageCompound(page)); | |
1283 | if (flags & FOLL_GET) | |
70b50f94 | 1284 | get_page_foll(page); |
71e3aac0 AA |
1285 | |
1286 | out: | |
1287 | return page; | |
1288 | } | |
1289 | ||
d10e63f2 | 1290 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1291 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1292 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1293 | { |
b32967ff | 1294 | struct page *page; |
d10e63f2 | 1295 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
4daae3b4 | 1296 | int target_nid; |
03c5a6e1 | 1297 | int current_nid = -1; |
b32967ff MG |
1298 | bool migrated; |
1299 | bool page_locked = false; | |
d10e63f2 MG |
1300 | |
1301 | spin_lock(&mm->page_table_lock); | |
1302 | if (unlikely(!pmd_same(pmd, *pmdp))) | |
1303 | goto out_unlock; | |
1304 | ||
1305 | page = pmd_page(pmd); | |
4daae3b4 | 1306 | get_page(page); |
03c5a6e1 MG |
1307 | current_nid = page_to_nid(page); |
1308 | count_vm_numa_event(NUMA_HINT_FAULTS); | |
1309 | if (current_nid == numa_node_id()) | |
1310 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); | |
4daae3b4 MG |
1311 | |
1312 | target_nid = mpol_misplaced(page, vma, haddr); | |
b32967ff MG |
1313 | if (target_nid == -1) { |
1314 | put_page(page); | |
4daae3b4 | 1315 | goto clear_pmdnuma; |
b32967ff | 1316 | } |
4daae3b4 | 1317 | |
b32967ff MG |
1318 | /* Acquire the page lock to serialise THP migrations */ |
1319 | spin_unlock(&mm->page_table_lock); | |
1320 | lock_page(page); | |
1321 | page_locked = true; | |
4daae3b4 | 1322 | |
b32967ff | 1323 | /* Confirm the PTE did not while locked */ |
4daae3b4 | 1324 | spin_lock(&mm->page_table_lock); |
b32967ff MG |
1325 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1326 | unlock_page(page); | |
1327 | put_page(page); | |
4daae3b4 | 1328 | goto out_unlock; |
b32967ff MG |
1329 | } |
1330 | spin_unlock(&mm->page_table_lock); | |
4daae3b4 | 1331 | |
b32967ff MG |
1332 | /* Migrate the THP to the requested node */ |
1333 | migrated = migrate_misplaced_transhuge_page(mm, vma, | |
1334 | pmdp, pmd, addr, | |
1335 | page, target_nid); | |
1336 | if (migrated) | |
1337 | current_nid = target_nid; | |
1338 | else { | |
1339 | spin_lock(&mm->page_table_lock); | |
1340 | if (unlikely(!pmd_same(pmd, *pmdp))) { | |
1341 | unlock_page(page); | |
1342 | goto out_unlock; | |
1343 | } | |
1344 | goto clear_pmdnuma; | |
1345 | } | |
1346 | ||
1347 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
1348 | return 0; | |
1349 | ||
1350 | clear_pmdnuma: | |
d10e63f2 MG |
1351 | pmd = pmd_mknonnuma(pmd); |
1352 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1353 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1354 | update_mmu_cache_pmd(vma, addr, pmdp); | |
b32967ff MG |
1355 | if (page_locked) |
1356 | unlock_page(page); | |
d10e63f2 MG |
1357 | |
1358 | out_unlock: | |
1359 | spin_unlock(&mm->page_table_lock); | |
b32967ff MG |
1360 | if (current_nid != -1) |
1361 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
d10e63f2 MG |
1362 | return 0; |
1363 | } | |
1364 | ||
71e3aac0 | 1365 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1366 | pmd_t *pmd, unsigned long addr) |
71e3aac0 AA |
1367 | { |
1368 | int ret = 0; | |
1369 | ||
025c5b24 NH |
1370 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1371 | struct page *page; | |
1372 | pgtable_t pgtable; | |
f5c8ad47 | 1373 | pmd_t orig_pmd; |
e3ebcf64 | 1374 | pgtable = pgtable_trans_huge_withdraw(tlb->mm); |
f5c8ad47 | 1375 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1376 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
479f0abb KS |
1377 | if (is_huge_zero_pmd(orig_pmd)) { |
1378 | tlb->mm->nr_ptes--; | |
1379 | spin_unlock(&tlb->mm->page_table_lock); | |
97ae1749 | 1380 | put_huge_zero_page(); |
479f0abb KS |
1381 | } else { |
1382 | page = pmd_page(orig_pmd); | |
1383 | page_remove_rmap(page); | |
1384 | VM_BUG_ON(page_mapcount(page) < 0); | |
1385 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1386 | VM_BUG_ON(!PageHead(page)); | |
1387 | tlb->mm->nr_ptes--; | |
1388 | spin_unlock(&tlb->mm->page_table_lock); | |
1389 | tlb_remove_page(tlb, page); | |
1390 | } | |
025c5b24 NH |
1391 | pte_free(tlb->mm, pgtable); |
1392 | ret = 1; | |
1393 | } | |
71e3aac0 AA |
1394 | return ret; |
1395 | } | |
1396 | ||
0ca1634d JW |
1397 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1398 | unsigned long addr, unsigned long end, | |
1399 | unsigned char *vec) | |
1400 | { | |
1401 | int ret = 0; | |
1402 | ||
025c5b24 NH |
1403 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1404 | /* | |
1405 | * All logical pages in the range are present | |
1406 | * if backed by a huge page. | |
1407 | */ | |
0ca1634d | 1408 | spin_unlock(&vma->vm_mm->page_table_lock); |
025c5b24 NH |
1409 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1410 | ret = 1; | |
1411 | } | |
0ca1634d JW |
1412 | |
1413 | return ret; | |
1414 | } | |
1415 | ||
37a1c49a AA |
1416 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1417 | unsigned long old_addr, | |
1418 | unsigned long new_addr, unsigned long old_end, | |
1419 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1420 | { | |
1421 | int ret = 0; | |
1422 | pmd_t pmd; | |
1423 | ||
1424 | struct mm_struct *mm = vma->vm_mm; | |
1425 | ||
1426 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1427 | (new_addr & ~HPAGE_PMD_MASK) || | |
1428 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1429 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1430 | goto out; | |
1431 | ||
1432 | /* | |
1433 | * The destination pmd shouldn't be established, free_pgtables() | |
1434 | * should have release it. | |
1435 | */ | |
1436 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1437 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1438 | goto out; | |
1439 | } | |
1440 | ||
025c5b24 NH |
1441 | ret = __pmd_trans_huge_lock(old_pmd, vma); |
1442 | if (ret == 1) { | |
1443 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); | |
1444 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
1445 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
37a1c49a AA |
1446 | spin_unlock(&mm->page_table_lock); |
1447 | } | |
1448 | out: | |
1449 | return ret; | |
1450 | } | |
1451 | ||
cd7548ab | 1452 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1453 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1454 | { |
1455 | struct mm_struct *mm = vma->vm_mm; | |
1456 | int ret = 0; | |
1457 | ||
025c5b24 NH |
1458 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1459 | pmd_t entry; | |
1460 | entry = pmdp_get_and_clear(mm, addr, pmd); | |
a4f1de17 | 1461 | if (!prot_numa) { |
4b10e7d5 | 1462 | entry = pmd_modify(entry, newprot); |
a4f1de17 HD |
1463 | BUG_ON(pmd_write(entry)); |
1464 | } else { | |
4b10e7d5 MG |
1465 | struct page *page = pmd_page(*pmd); |
1466 | ||
1467 | /* only check non-shared pages */ | |
1468 | if (page_mapcount(page) == 1 && | |
1469 | !pmd_numa(*pmd)) { | |
1470 | entry = pmd_mknuma(entry); | |
1471 | } | |
1472 | } | |
025c5b24 NH |
1473 | set_pmd_at(mm, addr, pmd, entry); |
1474 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1475 | ret = 1; | |
1476 | } | |
1477 | ||
1478 | return ret; | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1483 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1484 | * | |
1485 | * Note that if it returns 1, this routine returns without unlocking page | |
1486 | * table locks. So callers must unlock them. | |
1487 | */ | |
1488 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) | |
1489 | { | |
1490 | spin_lock(&vma->vm_mm->page_table_lock); | |
cd7548ab JW |
1491 | if (likely(pmd_trans_huge(*pmd))) { |
1492 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
025c5b24 | 1493 | spin_unlock(&vma->vm_mm->page_table_lock); |
cd7548ab | 1494 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1495 | return -1; |
cd7548ab | 1496 | } else { |
025c5b24 NH |
1497 | /* Thp mapped by 'pmd' is stable, so we can |
1498 | * handle it as it is. */ | |
1499 | return 1; | |
cd7548ab | 1500 | } |
025c5b24 NH |
1501 | } |
1502 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1503 | return 0; | |
cd7548ab JW |
1504 | } |
1505 | ||
71e3aac0 AA |
1506 | pmd_t *page_check_address_pmd(struct page *page, |
1507 | struct mm_struct *mm, | |
1508 | unsigned long address, | |
1509 | enum page_check_address_pmd_flag flag) | |
1510 | { | |
71e3aac0 AA |
1511 | pmd_t *pmd, *ret = NULL; |
1512 | ||
1513 | if (address & ~HPAGE_PMD_MASK) | |
1514 | goto out; | |
1515 | ||
6219049a BL |
1516 | pmd = mm_find_pmd(mm, address); |
1517 | if (!pmd) | |
71e3aac0 | 1518 | goto out; |
71e3aac0 AA |
1519 | if (pmd_none(*pmd)) |
1520 | goto out; | |
1521 | if (pmd_page(*pmd) != page) | |
1522 | goto out; | |
94fcc585 AA |
1523 | /* |
1524 | * split_vma() may create temporary aliased mappings. There is | |
1525 | * no risk as long as all huge pmd are found and have their | |
1526 | * splitting bit set before __split_huge_page_refcount | |
1527 | * runs. Finding the same huge pmd more than once during the | |
1528 | * same rmap walk is not a problem. | |
1529 | */ | |
1530 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1531 | pmd_trans_splitting(*pmd)) | |
1532 | goto out; | |
71e3aac0 AA |
1533 | if (pmd_trans_huge(*pmd)) { |
1534 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1535 | !pmd_trans_splitting(*pmd)); | |
1536 | ret = pmd; | |
1537 | } | |
1538 | out: | |
1539 | return ret; | |
1540 | } | |
1541 | ||
1542 | static int __split_huge_page_splitting(struct page *page, | |
1543 | struct vm_area_struct *vma, | |
1544 | unsigned long address) | |
1545 | { | |
1546 | struct mm_struct *mm = vma->vm_mm; | |
1547 | pmd_t *pmd; | |
1548 | int ret = 0; | |
2ec74c3e SG |
1549 | /* For mmu_notifiers */ |
1550 | const unsigned long mmun_start = address; | |
1551 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1552 | |
2ec74c3e | 1553 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1554 | spin_lock(&mm->page_table_lock); |
1555 | pmd = page_check_address_pmd(page, mm, address, | |
1556 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); | |
1557 | if (pmd) { | |
1558 | /* | |
1559 | * We can't temporarily set the pmd to null in order | |
1560 | * to split it, the pmd must remain marked huge at all | |
1561 | * times or the VM won't take the pmd_trans_huge paths | |
5a505085 | 1562 | * and it won't wait on the anon_vma->root->rwsem to |
71e3aac0 AA |
1563 | * serialize against split_huge_page*. |
1564 | */ | |
2ec74c3e | 1565 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 AA |
1566 | ret = 1; |
1567 | } | |
1568 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1569 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1570 | |
1571 | return ret; | |
1572 | } | |
1573 | ||
1574 | static void __split_huge_page_refcount(struct page *page) | |
1575 | { | |
1576 | int i; | |
71e3aac0 | 1577 | struct zone *zone = page_zone(page); |
fa9add64 | 1578 | struct lruvec *lruvec; |
70b50f94 | 1579 | int tail_count = 0; |
71e3aac0 AA |
1580 | |
1581 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1582 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1583 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1584 | ||
71e3aac0 | 1585 | compound_lock(page); |
e94c8a9c KH |
1586 | /* complete memcg works before add pages to LRU */ |
1587 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1588 | |
45676885 | 1589 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1590 | struct page *page_tail = page + i; |
1591 | ||
70b50f94 AA |
1592 | /* tail_page->_mapcount cannot change */ |
1593 | BUG_ON(page_mapcount(page_tail) < 0); | |
1594 | tail_count += page_mapcount(page_tail); | |
1595 | /* check for overflow */ | |
1596 | BUG_ON(tail_count < 0); | |
1597 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1598 | /* | |
1599 | * tail_page->_count is zero and not changing from | |
1600 | * under us. But get_page_unless_zero() may be running | |
1601 | * from under us on the tail_page. If we used | |
1602 | * atomic_set() below instead of atomic_add(), we | |
1603 | * would then run atomic_set() concurrently with | |
1604 | * get_page_unless_zero(), and atomic_set() is | |
1605 | * implemented in C not using locked ops. spin_unlock | |
1606 | * on x86 sometime uses locked ops because of PPro | |
1607 | * errata 66, 92, so unless somebody can guarantee | |
1608 | * atomic_set() here would be safe on all archs (and | |
1609 | * not only on x86), it's safer to use atomic_add(). | |
1610 | */ | |
1611 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1612 | &page_tail->_count); | |
71e3aac0 AA |
1613 | |
1614 | /* after clearing PageTail the gup refcount can be released */ | |
1615 | smp_mb(); | |
1616 | ||
a6d30ddd JD |
1617 | /* |
1618 | * retain hwpoison flag of the poisoned tail page: | |
1619 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1620 | * by the memory-failure. | |
1621 | */ | |
1622 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1623 | page_tail->flags |= (page->flags & |
1624 | ((1L << PG_referenced) | | |
1625 | (1L << PG_swapbacked) | | |
1626 | (1L << PG_mlocked) | | |
1627 | (1L << PG_uptodate))); | |
1628 | page_tail->flags |= (1L << PG_dirty); | |
1629 | ||
70b50f94 | 1630 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1631 | smp_wmb(); |
1632 | ||
1633 | /* | |
1634 | * __split_huge_page_splitting() already set the | |
1635 | * splitting bit in all pmd that could map this | |
1636 | * hugepage, that will ensure no CPU can alter the | |
1637 | * mapcount on the head page. The mapcount is only | |
1638 | * accounted in the head page and it has to be | |
1639 | * transferred to all tail pages in the below code. So | |
1640 | * for this code to be safe, the split the mapcount | |
1641 | * can't change. But that doesn't mean userland can't | |
1642 | * keep changing and reading the page contents while | |
1643 | * we transfer the mapcount, so the pmd splitting | |
1644 | * status is achieved setting a reserved bit in the | |
1645 | * pmd, not by clearing the present bit. | |
1646 | */ | |
71e3aac0 AA |
1647 | page_tail->_mapcount = page->_mapcount; |
1648 | ||
1649 | BUG_ON(page_tail->mapping); | |
1650 | page_tail->mapping = page->mapping; | |
1651 | ||
45676885 | 1652 | page_tail->index = page->index + i; |
5aa80374 | 1653 | page_xchg_last_nid(page_tail, page_last_nid(page)); |
71e3aac0 AA |
1654 | |
1655 | BUG_ON(!PageAnon(page_tail)); | |
1656 | BUG_ON(!PageUptodate(page_tail)); | |
1657 | BUG_ON(!PageDirty(page_tail)); | |
1658 | BUG_ON(!PageSwapBacked(page_tail)); | |
1659 | ||
fa9add64 | 1660 | lru_add_page_tail(page, page_tail, lruvec); |
71e3aac0 | 1661 | } |
70b50f94 AA |
1662 | atomic_sub(tail_count, &page->_count); |
1663 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1664 | |
fa9add64 | 1665 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 AA |
1666 | __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); |
1667 | ||
71e3aac0 AA |
1668 | ClearPageCompound(page); |
1669 | compound_unlock(page); | |
1670 | spin_unlock_irq(&zone->lru_lock); | |
1671 | ||
1672 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1673 | struct page *page_tail = page + i; | |
1674 | BUG_ON(page_count(page_tail) <= 0); | |
1675 | /* | |
1676 | * Tail pages may be freed if there wasn't any mapping | |
1677 | * like if add_to_swap() is running on a lru page that | |
1678 | * had its mapping zapped. And freeing these pages | |
1679 | * requires taking the lru_lock so we do the put_page | |
1680 | * of the tail pages after the split is complete. | |
1681 | */ | |
1682 | put_page(page_tail); | |
1683 | } | |
1684 | ||
1685 | /* | |
1686 | * Only the head page (now become a regular page) is required | |
1687 | * to be pinned by the caller. | |
1688 | */ | |
1689 | BUG_ON(page_count(page) <= 0); | |
1690 | } | |
1691 | ||
1692 | static int __split_huge_page_map(struct page *page, | |
1693 | struct vm_area_struct *vma, | |
1694 | unsigned long address) | |
1695 | { | |
1696 | struct mm_struct *mm = vma->vm_mm; | |
1697 | pmd_t *pmd, _pmd; | |
1698 | int ret = 0, i; | |
1699 | pgtable_t pgtable; | |
1700 | unsigned long haddr; | |
1701 | ||
1702 | spin_lock(&mm->page_table_lock); | |
1703 | pmd = page_check_address_pmd(page, mm, address, | |
1704 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); | |
1705 | if (pmd) { | |
e3ebcf64 | 1706 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1707 | pmd_populate(mm, &_pmd, pgtable); |
1708 | ||
e3ebcf64 GS |
1709 | haddr = address; |
1710 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1711 | pte_t *pte, entry; |
1712 | BUG_ON(PageCompound(page+i)); | |
1713 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1714 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1715 | if (!pmd_write(*pmd)) | |
1716 | entry = pte_wrprotect(entry); | |
1717 | else | |
1718 | BUG_ON(page_mapcount(page) != 1); | |
1719 | if (!pmd_young(*pmd)) | |
1720 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1721 | if (pmd_numa(*pmd)) |
1722 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1723 | pte = pte_offset_map(&_pmd, haddr); |
1724 | BUG_ON(!pte_none(*pte)); | |
1725 | set_pte_at(mm, haddr, pte, entry); | |
1726 | pte_unmap(pte); | |
1727 | } | |
1728 | ||
71e3aac0 AA |
1729 | smp_wmb(); /* make pte visible before pmd */ |
1730 | /* | |
1731 | * Up to this point the pmd is present and huge and | |
1732 | * userland has the whole access to the hugepage | |
1733 | * during the split (which happens in place). If we | |
1734 | * overwrite the pmd with the not-huge version | |
1735 | * pointing to the pte here (which of course we could | |
1736 | * if all CPUs were bug free), userland could trigger | |
1737 | * a small page size TLB miss on the small sized TLB | |
1738 | * while the hugepage TLB entry is still established | |
1739 | * in the huge TLB. Some CPU doesn't like that. See | |
1740 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1741 | * Erratum 383 on page 93. Intel should be safe but is | |
1742 | * also warns that it's only safe if the permission | |
1743 | * and cache attributes of the two entries loaded in | |
1744 | * the two TLB is identical (which should be the case | |
1745 | * here). But it is generally safer to never allow | |
1746 | * small and huge TLB entries for the same virtual | |
1747 | * address to be loaded simultaneously. So instead of | |
1748 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1749 | * mark the current pmd notpresent (atomically because | |
1750 | * here the pmd_trans_huge and pmd_trans_splitting | |
1751 | * must remain set at all times on the pmd until the | |
1752 | * split is complete for this pmd), then we flush the | |
1753 | * SMP TLB and finally we write the non-huge version | |
1754 | * of the pmd entry with pmd_populate. | |
1755 | */ | |
46dcde73 | 1756 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1757 | pmd_populate(mm, pmd, pgtable); |
1758 | ret = 1; | |
1759 | } | |
1760 | spin_unlock(&mm->page_table_lock); | |
1761 | ||
1762 | return ret; | |
1763 | } | |
1764 | ||
5a505085 | 1765 | /* must be called with anon_vma->root->rwsem held */ |
71e3aac0 AA |
1766 | static void __split_huge_page(struct page *page, |
1767 | struct anon_vma *anon_vma) | |
1768 | { | |
1769 | int mapcount, mapcount2; | |
bf181b9f | 1770 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1771 | struct anon_vma_chain *avc; |
1772 | ||
1773 | BUG_ON(!PageHead(page)); | |
1774 | BUG_ON(PageTail(page)); | |
1775 | ||
1776 | mapcount = 0; | |
bf181b9f | 1777 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1778 | struct vm_area_struct *vma = avc->vma; |
1779 | unsigned long addr = vma_address(page, vma); | |
1780 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1781 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1782 | } | |
05759d38 AA |
1783 | /* |
1784 | * It is critical that new vmas are added to the tail of the | |
1785 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1786 | * and establishes a child pmd before | |
1787 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1788 | * we fail to prevent copy_huge_pmd() from running until the | |
1789 | * whole __split_huge_page() is complete), we will still see | |
1790 | * the newly established pmd of the child later during the | |
1791 | * walk, to be able to set it as pmd_trans_splitting too. | |
1792 | */ | |
1793 | if (mapcount != page_mapcount(page)) | |
1794 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1795 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1796 | BUG_ON(mapcount != page_mapcount(page)); |
1797 | ||
1798 | __split_huge_page_refcount(page); | |
1799 | ||
1800 | mapcount2 = 0; | |
bf181b9f | 1801 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1802 | struct vm_area_struct *vma = avc->vma; |
1803 | unsigned long addr = vma_address(page, vma); | |
1804 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1805 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1806 | } | |
05759d38 AA |
1807 | if (mapcount != mapcount2) |
1808 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1809 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1810 | BUG_ON(mapcount != mapcount2); |
1811 | } | |
1812 | ||
1813 | int split_huge_page(struct page *page) | |
1814 | { | |
1815 | struct anon_vma *anon_vma; | |
1816 | int ret = 1; | |
1817 | ||
c5a647d0 | 1818 | BUG_ON(is_huge_zero_pfn(page_to_pfn(page))); |
71e3aac0 | 1819 | BUG_ON(!PageAnon(page)); |
062f1af2 MG |
1820 | |
1821 | /* | |
1822 | * The caller does not necessarily hold an mmap_sem that would prevent | |
1823 | * the anon_vma disappearing so we first we take a reference to it | |
1824 | * and then lock the anon_vma for write. This is similar to | |
1825 | * page_lock_anon_vma_read except the write lock is taken to serialise | |
1826 | * against parallel split or collapse operations. | |
1827 | */ | |
1828 | anon_vma = page_get_anon_vma(page); | |
71e3aac0 AA |
1829 | if (!anon_vma) |
1830 | goto out; | |
062f1af2 MG |
1831 | anon_vma_lock_write(anon_vma); |
1832 | ||
71e3aac0 AA |
1833 | ret = 0; |
1834 | if (!PageCompound(page)) | |
1835 | goto out_unlock; | |
1836 | ||
1837 | BUG_ON(!PageSwapBacked(page)); | |
1838 | __split_huge_page(page, anon_vma); | |
81ab4201 | 1839 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1840 | |
1841 | BUG_ON(PageCompound(page)); | |
1842 | out_unlock: | |
062f1af2 MG |
1843 | anon_vma_unlock(anon_vma); |
1844 | put_anon_vma(anon_vma); | |
71e3aac0 AA |
1845 | out: |
1846 | return ret; | |
1847 | } | |
1848 | ||
4b6e1e37 | 1849 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1850 | |
60ab3244 AA |
1851 | int hugepage_madvise(struct vm_area_struct *vma, |
1852 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1853 | { |
8e72033f GS |
1854 | struct mm_struct *mm = vma->vm_mm; |
1855 | ||
a664b2d8 AA |
1856 | switch (advice) { |
1857 | case MADV_HUGEPAGE: | |
1858 | /* | |
1859 | * Be somewhat over-protective like KSM for now! | |
1860 | */ | |
78f11a25 | 1861 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1862 | return -EINVAL; |
8e72033f GS |
1863 | if (mm->def_flags & VM_NOHUGEPAGE) |
1864 | return -EINVAL; | |
a664b2d8 AA |
1865 | *vm_flags &= ~VM_NOHUGEPAGE; |
1866 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1867 | /* |
1868 | * If the vma become good for khugepaged to scan, | |
1869 | * register it here without waiting a page fault that | |
1870 | * may not happen any time soon. | |
1871 | */ | |
1872 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1873 | return -ENOMEM; | |
a664b2d8 AA |
1874 | break; |
1875 | case MADV_NOHUGEPAGE: | |
1876 | /* | |
1877 | * Be somewhat over-protective like KSM for now! | |
1878 | */ | |
78f11a25 | 1879 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1880 | return -EINVAL; |
1881 | *vm_flags &= ~VM_HUGEPAGE; | |
1882 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1883 | /* |
1884 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1885 | * this vma even if we leave the mm registered in khugepaged if | |
1886 | * it got registered before VM_NOHUGEPAGE was set. | |
1887 | */ | |
a664b2d8 AA |
1888 | break; |
1889 | } | |
0af4e98b AA |
1890 | |
1891 | return 0; | |
1892 | } | |
1893 | ||
ba76149f AA |
1894 | static int __init khugepaged_slab_init(void) |
1895 | { | |
1896 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1897 | sizeof(struct mm_slot), | |
1898 | __alignof__(struct mm_slot), 0, NULL); | |
1899 | if (!mm_slot_cache) | |
1900 | return -ENOMEM; | |
1901 | ||
1902 | return 0; | |
1903 | } | |
1904 | ||
ba76149f AA |
1905 | static inline struct mm_slot *alloc_mm_slot(void) |
1906 | { | |
1907 | if (!mm_slot_cache) /* initialization failed */ | |
1908 | return NULL; | |
1909 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1910 | } | |
1911 | ||
1912 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1913 | { | |
1914 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1915 | } | |
1916 | ||
ba76149f AA |
1917 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) |
1918 | { | |
1919 | struct mm_slot *mm_slot; | |
ba76149f AA |
1920 | struct hlist_node *node; |
1921 | ||
43b5fbbd | 1922 | hash_for_each_possible(mm_slots_hash, mm_slot, node, hash, (unsigned long)mm) |
ba76149f AA |
1923 | if (mm == mm_slot->mm) |
1924 | return mm_slot; | |
43b5fbbd | 1925 | |
ba76149f AA |
1926 | return NULL; |
1927 | } | |
1928 | ||
1929 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1930 | struct mm_slot *mm_slot) | |
1931 | { | |
ba76149f | 1932 | mm_slot->mm = mm; |
43b5fbbd | 1933 | hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); |
ba76149f AA |
1934 | } |
1935 | ||
1936 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1937 | { | |
1938 | return atomic_read(&mm->mm_users) == 0; | |
1939 | } | |
1940 | ||
1941 | int __khugepaged_enter(struct mm_struct *mm) | |
1942 | { | |
1943 | struct mm_slot *mm_slot; | |
1944 | int wakeup; | |
1945 | ||
1946 | mm_slot = alloc_mm_slot(); | |
1947 | if (!mm_slot) | |
1948 | return -ENOMEM; | |
1949 | ||
1950 | /* __khugepaged_exit() must not run from under us */ | |
1951 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1952 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1953 | free_mm_slot(mm_slot); | |
1954 | return 0; | |
1955 | } | |
1956 | ||
1957 | spin_lock(&khugepaged_mm_lock); | |
1958 | insert_to_mm_slots_hash(mm, mm_slot); | |
1959 | /* | |
1960 | * Insert just behind the scanning cursor, to let the area settle | |
1961 | * down a little. | |
1962 | */ | |
1963 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
1964 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
1965 | spin_unlock(&khugepaged_mm_lock); | |
1966 | ||
1967 | atomic_inc(&mm->mm_count); | |
1968 | if (wakeup) | |
1969 | wake_up_interruptible(&khugepaged_wait); | |
1970 | ||
1971 | return 0; | |
1972 | } | |
1973 | ||
1974 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
1975 | { | |
1976 | unsigned long hstart, hend; | |
1977 | if (!vma->anon_vma) | |
1978 | /* | |
1979 | * Not yet faulted in so we will register later in the | |
1980 | * page fault if needed. | |
1981 | */ | |
1982 | return 0; | |
78f11a25 | 1983 | if (vma->vm_ops) |
ba76149f AA |
1984 | /* khugepaged not yet working on file or special mappings */ |
1985 | return 0; | |
b3b9c293 | 1986 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
1987 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
1988 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
1989 | if (hstart < hend) | |
1990 | return khugepaged_enter(vma); | |
1991 | return 0; | |
1992 | } | |
1993 | ||
1994 | void __khugepaged_exit(struct mm_struct *mm) | |
1995 | { | |
1996 | struct mm_slot *mm_slot; | |
1997 | int free = 0; | |
1998 | ||
1999 | spin_lock(&khugepaged_mm_lock); | |
2000 | mm_slot = get_mm_slot(mm); | |
2001 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
43b5fbbd | 2002 | hash_del(&mm_slot->hash); |
ba76149f AA |
2003 | list_del(&mm_slot->mm_node); |
2004 | free = 1; | |
2005 | } | |
d788e80a | 2006 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
2007 | |
2008 | if (free) { | |
ba76149f AA |
2009 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
2010 | free_mm_slot(mm_slot); | |
2011 | mmdrop(mm); | |
2012 | } else if (mm_slot) { | |
ba76149f AA |
2013 | /* |
2014 | * This is required to serialize against | |
2015 | * khugepaged_test_exit() (which is guaranteed to run | |
2016 | * under mmap sem read mode). Stop here (after we | |
2017 | * return all pagetables will be destroyed) until | |
2018 | * khugepaged has finished working on the pagetables | |
2019 | * under the mmap_sem. | |
2020 | */ | |
2021 | down_write(&mm->mmap_sem); | |
2022 | up_write(&mm->mmap_sem); | |
d788e80a | 2023 | } |
ba76149f AA |
2024 | } |
2025 | ||
2026 | static void release_pte_page(struct page *page) | |
2027 | { | |
2028 | /* 0 stands for page_is_file_cache(page) == false */ | |
2029 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2030 | unlock_page(page); | |
2031 | putback_lru_page(page); | |
2032 | } | |
2033 | ||
2034 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
2035 | { | |
2036 | while (--_pte >= pte) { | |
2037 | pte_t pteval = *_pte; | |
2038 | if (!pte_none(pteval)) | |
2039 | release_pte_page(pte_page(pteval)); | |
2040 | } | |
2041 | } | |
2042 | ||
ba76149f AA |
2043 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
2044 | unsigned long address, | |
2045 | pte_t *pte) | |
2046 | { | |
2047 | struct page *page; | |
2048 | pte_t *_pte; | |
344aa35c | 2049 | int referenced = 0, none = 0; |
ba76149f AA |
2050 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
2051 | _pte++, address += PAGE_SIZE) { | |
2052 | pte_t pteval = *_pte; | |
2053 | if (pte_none(pteval)) { | |
2054 | if (++none <= khugepaged_max_ptes_none) | |
2055 | continue; | |
344aa35c | 2056 | else |
ba76149f | 2057 | goto out; |
ba76149f | 2058 | } |
344aa35c | 2059 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 2060 | goto out; |
ba76149f | 2061 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 2062 | if (unlikely(!page)) |
ba76149f | 2063 | goto out; |
344aa35c | 2064 | |
ba76149f AA |
2065 | VM_BUG_ON(PageCompound(page)); |
2066 | BUG_ON(!PageAnon(page)); | |
2067 | VM_BUG_ON(!PageSwapBacked(page)); | |
2068 | ||
2069 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 2070 | if (page_count(page) != 1) |
ba76149f | 2071 | goto out; |
ba76149f AA |
2072 | /* |
2073 | * We can do it before isolate_lru_page because the | |
2074 | * page can't be freed from under us. NOTE: PG_lock | |
2075 | * is needed to serialize against split_huge_page | |
2076 | * when invoked from the VM. | |
2077 | */ | |
344aa35c | 2078 | if (!trylock_page(page)) |
ba76149f | 2079 | goto out; |
ba76149f AA |
2080 | /* |
2081 | * Isolate the page to avoid collapsing an hugepage | |
2082 | * currently in use by the VM. | |
2083 | */ | |
2084 | if (isolate_lru_page(page)) { | |
2085 | unlock_page(page); | |
ba76149f AA |
2086 | goto out; |
2087 | } | |
2088 | /* 0 stands for page_is_file_cache(page) == false */ | |
2089 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2090 | VM_BUG_ON(!PageLocked(page)); | |
2091 | VM_BUG_ON(PageLRU(page)); | |
2092 | ||
2093 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
2094 | if (pte_young(pteval) || PageReferenced(page) || |
2095 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2096 | referenced = 1; |
2097 | } | |
344aa35c BL |
2098 | if (likely(referenced)) |
2099 | return 1; | |
ba76149f | 2100 | out: |
344aa35c BL |
2101 | release_pte_pages(pte, _pte); |
2102 | return 0; | |
ba76149f AA |
2103 | } |
2104 | ||
2105 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
2106 | struct vm_area_struct *vma, | |
2107 | unsigned long address, | |
2108 | spinlock_t *ptl) | |
2109 | { | |
2110 | pte_t *_pte; | |
2111 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
2112 | pte_t pteval = *_pte; | |
2113 | struct page *src_page; | |
2114 | ||
2115 | if (pte_none(pteval)) { | |
2116 | clear_user_highpage(page, address); | |
2117 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
2118 | } else { | |
2119 | src_page = pte_page(pteval); | |
2120 | copy_user_highpage(page, src_page, address, vma); | |
2121 | VM_BUG_ON(page_mapcount(src_page) != 1); | |
ba76149f AA |
2122 | release_pte_page(src_page); |
2123 | /* | |
2124 | * ptl mostly unnecessary, but preempt has to | |
2125 | * be disabled to update the per-cpu stats | |
2126 | * inside page_remove_rmap(). | |
2127 | */ | |
2128 | spin_lock(ptl); | |
2129 | /* | |
2130 | * paravirt calls inside pte_clear here are | |
2131 | * superfluous. | |
2132 | */ | |
2133 | pte_clear(vma->vm_mm, address, _pte); | |
2134 | page_remove_rmap(src_page); | |
2135 | spin_unlock(ptl); | |
2136 | free_page_and_swap_cache(src_page); | |
2137 | } | |
2138 | ||
2139 | address += PAGE_SIZE; | |
2140 | page++; | |
2141 | } | |
2142 | } | |
2143 | ||
26234f36 | 2144 | static void khugepaged_alloc_sleep(void) |
ba76149f | 2145 | { |
26234f36 XG |
2146 | wait_event_freezable_timeout(khugepaged_wait, false, |
2147 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
2148 | } | |
ba76149f | 2149 | |
26234f36 XG |
2150 | #ifdef CONFIG_NUMA |
2151 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2152 | { | |
2153 | if (IS_ERR(*hpage)) { | |
2154 | if (!*wait) | |
2155 | return false; | |
2156 | ||
2157 | *wait = false; | |
e3b4126c | 2158 | *hpage = NULL; |
26234f36 XG |
2159 | khugepaged_alloc_sleep(); |
2160 | } else if (*hpage) { | |
2161 | put_page(*hpage); | |
2162 | *hpage = NULL; | |
2163 | } | |
2164 | ||
2165 | return true; | |
2166 | } | |
2167 | ||
2168 | static struct page | |
2169 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2170 | struct vm_area_struct *vma, unsigned long address, | |
2171 | int node) | |
2172 | { | |
0bbbc0b3 | 2173 | VM_BUG_ON(*hpage); |
ce83d217 AA |
2174 | /* |
2175 | * Allocate the page while the vma is still valid and under | |
2176 | * the mmap_sem read mode so there is no memory allocation | |
2177 | * later when we take the mmap_sem in write mode. This is more | |
2178 | * friendly behavior (OTOH it may actually hide bugs) to | |
2179 | * filesystems in userland with daemons allocating memory in | |
2180 | * the userland I/O paths. Allocating memory with the | |
2181 | * mmap_sem in read mode is good idea also to allow greater | |
2182 | * scalability. | |
2183 | */ | |
26234f36 | 2184 | *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, |
cc5d462f | 2185 | node, __GFP_OTHER_NODE); |
692e0b35 AA |
2186 | |
2187 | /* | |
2188 | * After allocating the hugepage, release the mmap_sem read lock in | |
2189 | * preparation for taking it in write mode. | |
2190 | */ | |
2191 | up_read(&mm->mmap_sem); | |
26234f36 | 2192 | if (unlikely(!*hpage)) { |
81ab4201 | 2193 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2194 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2195 | return NULL; |
ce83d217 | 2196 | } |
26234f36 | 2197 | |
65b3c07b | 2198 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2199 | return *hpage; |
2200 | } | |
2201 | #else | |
2202 | static struct page *khugepaged_alloc_hugepage(bool *wait) | |
2203 | { | |
2204 | struct page *hpage; | |
2205 | ||
2206 | do { | |
2207 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2208 | if (!hpage) { | |
2209 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2210 | if (!*wait) | |
2211 | return NULL; | |
2212 | ||
2213 | *wait = false; | |
2214 | khugepaged_alloc_sleep(); | |
2215 | } else | |
2216 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2217 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2218 | ||
2219 | return hpage; | |
2220 | } | |
2221 | ||
2222 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2223 | { | |
2224 | if (!*hpage) | |
2225 | *hpage = khugepaged_alloc_hugepage(wait); | |
2226 | ||
2227 | if (unlikely(!*hpage)) | |
2228 | return false; | |
2229 | ||
2230 | return true; | |
2231 | } | |
2232 | ||
2233 | static struct page | |
2234 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2235 | struct vm_area_struct *vma, unsigned long address, | |
2236 | int node) | |
2237 | { | |
2238 | up_read(&mm->mmap_sem); | |
2239 | VM_BUG_ON(!*hpage); | |
2240 | return *hpage; | |
2241 | } | |
692e0b35 AA |
2242 | #endif |
2243 | ||
fa475e51 BL |
2244 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2245 | { | |
2246 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2247 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2248 | return false; | |
2249 | ||
2250 | if (!vma->anon_vma || vma->vm_ops) | |
2251 | return false; | |
2252 | if (is_vma_temporary_stack(vma)) | |
2253 | return false; | |
2254 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2255 | return true; | |
2256 | } | |
2257 | ||
26234f36 XG |
2258 | static void collapse_huge_page(struct mm_struct *mm, |
2259 | unsigned long address, | |
2260 | struct page **hpage, | |
2261 | struct vm_area_struct *vma, | |
2262 | int node) | |
2263 | { | |
26234f36 XG |
2264 | pmd_t *pmd, _pmd; |
2265 | pte_t *pte; | |
2266 | pgtable_t pgtable; | |
2267 | struct page *new_page; | |
2268 | spinlock_t *ptl; | |
2269 | int isolated; | |
2270 | unsigned long hstart, hend; | |
2ec74c3e SG |
2271 | unsigned long mmun_start; /* For mmu_notifiers */ |
2272 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2273 | |
2274 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2275 | ||
2276 | /* release the mmap_sem read lock. */ | |
2277 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2278 | if (!new_page) | |
2279 | return; | |
2280 | ||
420256ef | 2281 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2282 | return; |
ba76149f AA |
2283 | |
2284 | /* | |
2285 | * Prevent all access to pagetables with the exception of | |
2286 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2287 | * handled by the anon_vma lock + PG_lock. | |
2288 | */ | |
2289 | down_write(&mm->mmap_sem); | |
2290 | if (unlikely(khugepaged_test_exit(mm))) | |
2291 | goto out; | |
2292 | ||
2293 | vma = find_vma(mm, address); | |
2294 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; | |
2295 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2296 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2297 | goto out; | |
fa475e51 | 2298 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2299 | goto out; |
6219049a BL |
2300 | pmd = mm_find_pmd(mm, address); |
2301 | if (!pmd) | |
ba76149f | 2302 | goto out; |
6219049a | 2303 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2304 | goto out; |
2305 | ||
4fc3f1d6 | 2306 | anon_vma_lock_write(vma->anon_vma); |
ba76149f AA |
2307 | |
2308 | pte = pte_offset_map(pmd, address); | |
2309 | ptl = pte_lockptr(mm, pmd); | |
2310 | ||
2ec74c3e SG |
2311 | mmun_start = address; |
2312 | mmun_end = address + HPAGE_PMD_SIZE; | |
2313 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
ba76149f AA |
2314 | spin_lock(&mm->page_table_lock); /* probably unnecessary */ |
2315 | /* | |
2316 | * After this gup_fast can't run anymore. This also removes | |
2317 | * any huge TLB entry from the CPU so we won't allow | |
2318 | * huge and small TLB entries for the same virtual address | |
2319 | * to avoid the risk of CPU bugs in that area. | |
2320 | */ | |
2ec74c3e | 2321 | _pmd = pmdp_clear_flush(vma, address, pmd); |
ba76149f | 2322 | spin_unlock(&mm->page_table_lock); |
2ec74c3e | 2323 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f AA |
2324 | |
2325 | spin_lock(ptl); | |
2326 | isolated = __collapse_huge_page_isolate(vma, address, pte); | |
2327 | spin_unlock(ptl); | |
ba76149f AA |
2328 | |
2329 | if (unlikely(!isolated)) { | |
453c7192 | 2330 | pte_unmap(pte); |
ba76149f AA |
2331 | spin_lock(&mm->page_table_lock); |
2332 | BUG_ON(!pmd_none(*pmd)); | |
2333 | set_pmd_at(mm, address, pmd, _pmd); | |
2334 | spin_unlock(&mm->page_table_lock); | |
2335 | anon_vma_unlock(vma->anon_vma); | |
ce83d217 | 2336 | goto out; |
ba76149f AA |
2337 | } |
2338 | ||
2339 | /* | |
2340 | * All pages are isolated and locked so anon_vma rmap | |
2341 | * can't run anymore. | |
2342 | */ | |
2343 | anon_vma_unlock(vma->anon_vma); | |
2344 | ||
2345 | __collapse_huge_page_copy(pte, new_page, vma, address, ptl); | |
453c7192 | 2346 | pte_unmap(pte); |
ba76149f AA |
2347 | __SetPageUptodate(new_page); |
2348 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2349 | |
b3092b3b | 2350 | _pmd = mk_huge_pmd(new_page, vma); |
ba76149f AA |
2351 | |
2352 | /* | |
2353 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2354 | * this is needed to avoid the copy_huge_page writes to become | |
2355 | * visible after the set_pmd_at() write. | |
2356 | */ | |
2357 | smp_wmb(); | |
2358 | ||
2359 | spin_lock(&mm->page_table_lock); | |
2360 | BUG_ON(!pmd_none(*pmd)); | |
2361 | page_add_new_anon_rmap(new_page, vma, address); | |
2362 | set_pmd_at(mm, address, pmd, _pmd); | |
b113da65 | 2363 | update_mmu_cache_pmd(vma, address, pmd); |
e3ebcf64 | 2364 | pgtable_trans_huge_deposit(mm, pgtable); |
ba76149f AA |
2365 | spin_unlock(&mm->page_table_lock); |
2366 | ||
2367 | *hpage = NULL; | |
420256ef | 2368 | |
ba76149f | 2369 | khugepaged_pages_collapsed++; |
ce83d217 | 2370 | out_up_write: |
ba76149f | 2371 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2372 | return; |
2373 | ||
ce83d217 | 2374 | out: |
678ff896 | 2375 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2376 | goto out_up_write; |
ba76149f AA |
2377 | } |
2378 | ||
2379 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2380 | struct vm_area_struct *vma, | |
2381 | unsigned long address, | |
2382 | struct page **hpage) | |
2383 | { | |
ba76149f AA |
2384 | pmd_t *pmd; |
2385 | pte_t *pte, *_pte; | |
2386 | int ret = 0, referenced = 0, none = 0; | |
2387 | struct page *page; | |
2388 | unsigned long _address; | |
2389 | spinlock_t *ptl; | |
5c4b4be3 | 2390 | int node = -1; |
ba76149f AA |
2391 | |
2392 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2393 | ||
6219049a BL |
2394 | pmd = mm_find_pmd(mm, address); |
2395 | if (!pmd) | |
ba76149f | 2396 | goto out; |
6219049a | 2397 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2398 | goto out; |
2399 | ||
2400 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2401 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2402 | _pte++, _address += PAGE_SIZE) { | |
2403 | pte_t pteval = *_pte; | |
2404 | if (pte_none(pteval)) { | |
2405 | if (++none <= khugepaged_max_ptes_none) | |
2406 | continue; | |
2407 | else | |
2408 | goto out_unmap; | |
2409 | } | |
2410 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2411 | goto out_unmap; | |
2412 | page = vm_normal_page(vma, _address, pteval); | |
2413 | if (unlikely(!page)) | |
2414 | goto out_unmap; | |
5c4b4be3 AK |
2415 | /* |
2416 | * Chose the node of the first page. This could | |
2417 | * be more sophisticated and look at more pages, | |
2418 | * but isn't for now. | |
2419 | */ | |
2420 | if (node == -1) | |
2421 | node = page_to_nid(page); | |
ba76149f AA |
2422 | VM_BUG_ON(PageCompound(page)); |
2423 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) | |
2424 | goto out_unmap; | |
2425 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2426 | if (page_count(page) != 1) | |
2427 | goto out_unmap; | |
8ee53820 AA |
2428 | if (pte_young(pteval) || PageReferenced(page) || |
2429 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2430 | referenced = 1; |
2431 | } | |
2432 | if (referenced) | |
2433 | ret = 1; | |
2434 | out_unmap: | |
2435 | pte_unmap_unlock(pte, ptl); | |
ce83d217 AA |
2436 | if (ret) |
2437 | /* collapse_huge_page will return with the mmap_sem released */ | |
5c4b4be3 | 2438 | collapse_huge_page(mm, address, hpage, vma, node); |
ba76149f AA |
2439 | out: |
2440 | return ret; | |
2441 | } | |
2442 | ||
2443 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2444 | { | |
2445 | struct mm_struct *mm = mm_slot->mm; | |
2446 | ||
b9980cdc | 2447 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2448 | |
2449 | if (khugepaged_test_exit(mm)) { | |
2450 | /* free mm_slot */ | |
43b5fbbd | 2451 | hash_del(&mm_slot->hash); |
ba76149f AA |
2452 | list_del(&mm_slot->mm_node); |
2453 | ||
2454 | /* | |
2455 | * Not strictly needed because the mm exited already. | |
2456 | * | |
2457 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2458 | */ | |
2459 | ||
2460 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2461 | free_mm_slot(mm_slot); | |
2462 | mmdrop(mm); | |
2463 | } | |
2464 | } | |
2465 | ||
2466 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2467 | struct page **hpage) | |
2f1da642 HS |
2468 | __releases(&khugepaged_mm_lock) |
2469 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2470 | { |
2471 | struct mm_slot *mm_slot; | |
2472 | struct mm_struct *mm; | |
2473 | struct vm_area_struct *vma; | |
2474 | int progress = 0; | |
2475 | ||
2476 | VM_BUG_ON(!pages); | |
b9980cdc | 2477 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2478 | |
2479 | if (khugepaged_scan.mm_slot) | |
2480 | mm_slot = khugepaged_scan.mm_slot; | |
2481 | else { | |
2482 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2483 | struct mm_slot, mm_node); | |
2484 | khugepaged_scan.address = 0; | |
2485 | khugepaged_scan.mm_slot = mm_slot; | |
2486 | } | |
2487 | spin_unlock(&khugepaged_mm_lock); | |
2488 | ||
2489 | mm = mm_slot->mm; | |
2490 | down_read(&mm->mmap_sem); | |
2491 | if (unlikely(khugepaged_test_exit(mm))) | |
2492 | vma = NULL; | |
2493 | else | |
2494 | vma = find_vma(mm, khugepaged_scan.address); | |
2495 | ||
2496 | progress++; | |
2497 | for (; vma; vma = vma->vm_next) { | |
2498 | unsigned long hstart, hend; | |
2499 | ||
2500 | cond_resched(); | |
2501 | if (unlikely(khugepaged_test_exit(mm))) { | |
2502 | progress++; | |
2503 | break; | |
2504 | } | |
fa475e51 BL |
2505 | if (!hugepage_vma_check(vma)) { |
2506 | skip: | |
ba76149f AA |
2507 | progress++; |
2508 | continue; | |
2509 | } | |
ba76149f AA |
2510 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2511 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2512 | if (hstart >= hend) |
2513 | goto skip; | |
2514 | if (khugepaged_scan.address > hend) | |
2515 | goto skip; | |
ba76149f AA |
2516 | if (khugepaged_scan.address < hstart) |
2517 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2518 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2519 | |
2520 | while (khugepaged_scan.address < hend) { | |
2521 | int ret; | |
2522 | cond_resched(); | |
2523 | if (unlikely(khugepaged_test_exit(mm))) | |
2524 | goto breakouterloop; | |
2525 | ||
2526 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2527 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2528 | hend); | |
2529 | ret = khugepaged_scan_pmd(mm, vma, | |
2530 | khugepaged_scan.address, | |
2531 | hpage); | |
2532 | /* move to next address */ | |
2533 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2534 | progress += HPAGE_PMD_NR; | |
2535 | if (ret) | |
2536 | /* we released mmap_sem so break loop */ | |
2537 | goto breakouterloop_mmap_sem; | |
2538 | if (progress >= pages) | |
2539 | goto breakouterloop; | |
2540 | } | |
2541 | } | |
2542 | breakouterloop: | |
2543 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2544 | breakouterloop_mmap_sem: | |
2545 | ||
2546 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2547 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2548 | /* |
2549 | * Release the current mm_slot if this mm is about to die, or | |
2550 | * if we scanned all vmas of this mm. | |
2551 | */ | |
2552 | if (khugepaged_test_exit(mm) || !vma) { | |
2553 | /* | |
2554 | * Make sure that if mm_users is reaching zero while | |
2555 | * khugepaged runs here, khugepaged_exit will find | |
2556 | * mm_slot not pointing to the exiting mm. | |
2557 | */ | |
2558 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2559 | khugepaged_scan.mm_slot = list_entry( | |
2560 | mm_slot->mm_node.next, | |
2561 | struct mm_slot, mm_node); | |
2562 | khugepaged_scan.address = 0; | |
2563 | } else { | |
2564 | khugepaged_scan.mm_slot = NULL; | |
2565 | khugepaged_full_scans++; | |
2566 | } | |
2567 | ||
2568 | collect_mm_slot(mm_slot); | |
2569 | } | |
2570 | ||
2571 | return progress; | |
2572 | } | |
2573 | ||
2574 | static int khugepaged_has_work(void) | |
2575 | { | |
2576 | return !list_empty(&khugepaged_scan.mm_head) && | |
2577 | khugepaged_enabled(); | |
2578 | } | |
2579 | ||
2580 | static int khugepaged_wait_event(void) | |
2581 | { | |
2582 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2583 | kthread_should_stop(); |
ba76149f AA |
2584 | } |
2585 | ||
d516904b | 2586 | static void khugepaged_do_scan(void) |
ba76149f | 2587 | { |
d516904b | 2588 | struct page *hpage = NULL; |
ba76149f AA |
2589 | unsigned int progress = 0, pass_through_head = 0; |
2590 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2591 | bool wait = true; |
ba76149f AA |
2592 | |
2593 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2594 | ||
2595 | while (progress < pages) { | |
26234f36 | 2596 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2597 | break; |
26234f36 | 2598 | |
420256ef | 2599 | cond_resched(); |
ba76149f | 2600 | |
878aee7d AA |
2601 | if (unlikely(kthread_should_stop() || freezing(current))) |
2602 | break; | |
2603 | ||
ba76149f AA |
2604 | spin_lock(&khugepaged_mm_lock); |
2605 | if (!khugepaged_scan.mm_slot) | |
2606 | pass_through_head++; | |
2607 | if (khugepaged_has_work() && | |
2608 | pass_through_head < 2) | |
2609 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2610 | &hpage); |
ba76149f AA |
2611 | else |
2612 | progress = pages; | |
2613 | spin_unlock(&khugepaged_mm_lock); | |
2614 | } | |
ba76149f | 2615 | |
d516904b XG |
2616 | if (!IS_ERR_OR_NULL(hpage)) |
2617 | put_page(hpage); | |
0bbbc0b3 AA |
2618 | } |
2619 | ||
2017c0bf XG |
2620 | static void khugepaged_wait_work(void) |
2621 | { | |
2622 | try_to_freeze(); | |
2623 | ||
2624 | if (khugepaged_has_work()) { | |
2625 | if (!khugepaged_scan_sleep_millisecs) | |
2626 | return; | |
2627 | ||
2628 | wait_event_freezable_timeout(khugepaged_wait, | |
2629 | kthread_should_stop(), | |
2630 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2631 | return; | |
2632 | } | |
2633 | ||
2634 | if (khugepaged_enabled()) | |
2635 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2636 | } | |
2637 | ||
ba76149f AA |
2638 | static int khugepaged(void *none) |
2639 | { | |
2640 | struct mm_slot *mm_slot; | |
2641 | ||
878aee7d | 2642 | set_freezable(); |
ba76149f AA |
2643 | set_user_nice(current, 19); |
2644 | ||
b7231789 XG |
2645 | while (!kthread_should_stop()) { |
2646 | khugepaged_do_scan(); | |
2647 | khugepaged_wait_work(); | |
2648 | } | |
ba76149f AA |
2649 | |
2650 | spin_lock(&khugepaged_mm_lock); | |
2651 | mm_slot = khugepaged_scan.mm_slot; | |
2652 | khugepaged_scan.mm_slot = NULL; | |
2653 | if (mm_slot) | |
2654 | collect_mm_slot(mm_slot); | |
2655 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2656 | return 0; |
2657 | } | |
2658 | ||
c5a647d0 KS |
2659 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2660 | unsigned long haddr, pmd_t *pmd) | |
2661 | { | |
2662 | struct mm_struct *mm = vma->vm_mm; | |
2663 | pgtable_t pgtable; | |
2664 | pmd_t _pmd; | |
2665 | int i; | |
2666 | ||
2667 | pmdp_clear_flush(vma, haddr, pmd); | |
2668 | /* leave pmd empty until pte is filled */ | |
2669 | ||
2670 | pgtable = pgtable_trans_huge_withdraw(mm); | |
2671 | pmd_populate(mm, &_pmd, pgtable); | |
2672 | ||
2673 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2674 | pte_t *pte, entry; | |
2675 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2676 | entry = pte_mkspecial(entry); | |
2677 | pte = pte_offset_map(&_pmd, haddr); | |
2678 | VM_BUG_ON(!pte_none(*pte)); | |
2679 | set_pte_at(mm, haddr, pte, entry); | |
2680 | pte_unmap(pte); | |
2681 | } | |
2682 | smp_wmb(); /* make pte visible before pmd */ | |
2683 | pmd_populate(mm, pmd, pgtable); | |
97ae1749 | 2684 | put_huge_zero_page(); |
c5a647d0 KS |
2685 | } |
2686 | ||
e180377f KS |
2687 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2688 | pmd_t *pmd) | |
71e3aac0 AA |
2689 | { |
2690 | struct page *page; | |
e180377f | 2691 | struct mm_struct *mm = vma->vm_mm; |
c5a647d0 KS |
2692 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2693 | unsigned long mmun_start; /* For mmu_notifiers */ | |
2694 | unsigned long mmun_end; /* For mmu_notifiers */ | |
e180377f KS |
2695 | |
2696 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 | 2697 | |
c5a647d0 KS |
2698 | mmun_start = haddr; |
2699 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
2700 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
2701 | spin_lock(&mm->page_table_lock); |
2702 | if (unlikely(!pmd_trans_huge(*pmd))) { | |
2703 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 KS |
2704 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2705 | return; | |
2706 | } | |
2707 | if (is_huge_zero_pmd(*pmd)) { | |
2708 | __split_huge_zero_page_pmd(vma, haddr, pmd); | |
2709 | spin_unlock(&mm->page_table_lock); | |
2710 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
2711 | return; |
2712 | } | |
2713 | page = pmd_page(*pmd); | |
2714 | VM_BUG_ON(!page_count(page)); | |
2715 | get_page(page); | |
2716 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 | 2717 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2718 | |
2719 | split_huge_page(page); | |
2720 | ||
2721 | put_page(page); | |
2722 | BUG_ON(pmd_trans_huge(*pmd)); | |
2723 | } | |
94fcc585 | 2724 | |
e180377f KS |
2725 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2726 | pmd_t *pmd) | |
2727 | { | |
2728 | struct vm_area_struct *vma; | |
2729 | ||
2730 | vma = find_vma(mm, address); | |
2731 | BUG_ON(vma == NULL); | |
2732 | split_huge_page_pmd(vma, address, pmd); | |
2733 | } | |
2734 | ||
94fcc585 AA |
2735 | static void split_huge_page_address(struct mm_struct *mm, |
2736 | unsigned long address) | |
2737 | { | |
94fcc585 AA |
2738 | pmd_t *pmd; |
2739 | ||
2740 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2741 | ||
6219049a BL |
2742 | pmd = mm_find_pmd(mm, address); |
2743 | if (!pmd) | |
94fcc585 AA |
2744 | return; |
2745 | /* | |
2746 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2747 | * materialize from under us. | |
2748 | */ | |
e180377f | 2749 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2750 | } |
2751 | ||
2752 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2753 | unsigned long start, | |
2754 | unsigned long end, | |
2755 | long adjust_next) | |
2756 | { | |
2757 | /* | |
2758 | * If the new start address isn't hpage aligned and it could | |
2759 | * previously contain an hugepage: check if we need to split | |
2760 | * an huge pmd. | |
2761 | */ | |
2762 | if (start & ~HPAGE_PMD_MASK && | |
2763 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2764 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2765 | split_huge_page_address(vma->vm_mm, start); | |
2766 | ||
2767 | /* | |
2768 | * If the new end address isn't hpage aligned and it could | |
2769 | * previously contain an hugepage: check if we need to split | |
2770 | * an huge pmd. | |
2771 | */ | |
2772 | if (end & ~HPAGE_PMD_MASK && | |
2773 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2774 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2775 | split_huge_page_address(vma->vm_mm, end); | |
2776 | ||
2777 | /* | |
2778 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2779 | * vm_next->vm_start isn't page aligned and it could previously | |
2780 | * contain an hugepage: check if we need to split an huge pmd. | |
2781 | */ | |
2782 | if (adjust_next > 0) { | |
2783 | struct vm_area_struct *next = vma->vm_next; | |
2784 | unsigned long nstart = next->vm_start; | |
2785 | nstart += adjust_next << PAGE_SHIFT; | |
2786 | if (nstart & ~HPAGE_PMD_MASK && | |
2787 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2788 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2789 | split_huge_page_address(next->vm_mm, nstart); | |
2790 | } | |
2791 | } |