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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> |
97ae1749 | 23 | |
71e3aac0 AA |
24 | #include <asm/tlb.h> |
25 | #include <asm/pgalloc.h> | |
26 | #include "internal.h" | |
27 | ||
ba76149f AA |
28 | /* |
29 | * By default transparent hugepage support is enabled for all mappings | |
30 | * and khugepaged scans all mappings. Defrag is only invoked by | |
31 | * khugepaged hugepage allocations and by page faults inside | |
32 | * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived | |
33 | * allocations. | |
34 | */ | |
71e3aac0 | 35 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 36 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 37 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
38 | #endif |
39 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
40 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
41 | #endif | |
d39d33c3 | 42 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
79da5407 KS |
43 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
44 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f AA |
45 | |
46 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
47 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
48 | static unsigned int khugepaged_pages_collapsed; | |
49 | static unsigned int khugepaged_full_scans; | |
50 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
51 | /* during fragmentation poll the hugepage allocator once every minute */ | |
52 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
53 | static struct task_struct *khugepaged_thread __read_mostly; | |
54 | static DEFINE_MUTEX(khugepaged_mutex); | |
55 | static DEFINE_SPINLOCK(khugepaged_mm_lock); | |
56 | static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); | |
57 | /* | |
58 | * default collapse hugepages if there is at least one pte mapped like | |
59 | * it would have happened if the vma was large enough during page | |
60 | * fault. | |
61 | */ | |
62 | static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; | |
63 | ||
64 | static int khugepaged(void *none); | |
65 | static int mm_slots_hash_init(void); | |
66 | static int khugepaged_slab_init(void); | |
67 | static void khugepaged_slab_free(void); | |
68 | ||
69 | #define MM_SLOTS_HASH_HEADS 1024 | |
70 | static struct hlist_head *mm_slots_hash __read_mostly; | |
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)) { | |
ba76149f | 577 | printk(KERN_ERR "hugepage: failed kobject create\n"); |
569e5590 | 578 | return -ENOMEM; |
ba76149f AA |
579 | } |
580 | ||
569e5590 | 581 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f AA |
582 | if (err) { |
583 | printk(KERN_ERR "hugepage: failed register hugeage group\n"); | |
569e5590 | 584 | goto delete_obj; |
ba76149f AA |
585 | } |
586 | ||
569e5590 | 587 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f AA |
588 | if (err) { |
589 | printk(KERN_ERR "hugepage: failed register hugeage 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 | ||
637 | err = mm_slots_hash_init(); | |
638 | if (err) { | |
639 | khugepaged_slab_free(); | |
640 | goto out; | |
641 | } | |
642 | ||
97ae1749 KS |
643 | register_shrinker(&huge_zero_page_shrinker); |
644 | ||
97562cd2 RR |
645 | /* |
646 | * By default disable transparent hugepages on smaller systems, | |
647 | * where the extra memory used could hurt more than TLB overhead | |
648 | * is likely to save. The admin can still enable it through /sys. | |
649 | */ | |
650 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
651 | transparent_hugepage_flags = 0; | |
652 | ||
ba76149f AA |
653 | start_khugepaged(); |
654 | ||
569e5590 | 655 | return 0; |
ba76149f | 656 | out: |
569e5590 | 657 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 658 | return err; |
71e3aac0 AA |
659 | } |
660 | module_init(hugepage_init) | |
661 | ||
662 | static int __init setup_transparent_hugepage(char *str) | |
663 | { | |
664 | int ret = 0; | |
665 | if (!str) | |
666 | goto out; | |
667 | if (!strcmp(str, "always")) { | |
668 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
669 | &transparent_hugepage_flags); | |
670 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
671 | &transparent_hugepage_flags); | |
672 | ret = 1; | |
673 | } else if (!strcmp(str, "madvise")) { | |
674 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
675 | &transparent_hugepage_flags); | |
676 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
677 | &transparent_hugepage_flags); | |
678 | ret = 1; | |
679 | } else if (!strcmp(str, "never")) { | |
680 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
681 | &transparent_hugepage_flags); | |
682 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
683 | &transparent_hugepage_flags); | |
684 | ret = 1; | |
685 | } | |
686 | out: | |
687 | if (!ret) | |
688 | printk(KERN_WARNING | |
689 | "transparent_hugepage= cannot parse, ignored\n"); | |
690 | return ret; | |
691 | } | |
692 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
693 | ||
b32967ff | 694 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
695 | { |
696 | if (likely(vma->vm_flags & VM_WRITE)) | |
697 | pmd = pmd_mkwrite(pmd); | |
698 | return pmd; | |
699 | } | |
700 | ||
b3092b3b BL |
701 | static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma) |
702 | { | |
703 | pmd_t entry; | |
704 | entry = mk_pmd(page, vma->vm_page_prot); | |
705 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
706 | entry = pmd_mkhuge(entry); | |
707 | return entry; | |
708 | } | |
709 | ||
71e3aac0 AA |
710 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
711 | struct vm_area_struct *vma, | |
712 | unsigned long haddr, pmd_t *pmd, | |
713 | struct page *page) | |
714 | { | |
71e3aac0 AA |
715 | pgtable_t pgtable; |
716 | ||
717 | VM_BUG_ON(!PageCompound(page)); | |
718 | pgtable = pte_alloc_one(mm, haddr); | |
edad9d2c | 719 | if (unlikely(!pgtable)) |
71e3aac0 | 720 | return VM_FAULT_OOM; |
71e3aac0 AA |
721 | |
722 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
723 | __SetPageUptodate(page); | |
724 | ||
725 | spin_lock(&mm->page_table_lock); | |
726 | if (unlikely(!pmd_none(*pmd))) { | |
727 | spin_unlock(&mm->page_table_lock); | |
b9bbfbe3 | 728 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
729 | put_page(page); |
730 | pte_free(mm, pgtable); | |
731 | } else { | |
732 | pmd_t entry; | |
b3092b3b | 733 | entry = mk_huge_pmd(page, vma); |
71e3aac0 AA |
734 | /* |
735 | * The spinlocking to take the lru_lock inside | |
736 | * page_add_new_anon_rmap() acts as a full memory | |
737 | * barrier to be sure clear_huge_page writes become | |
738 | * visible after the set_pmd_at() write. | |
739 | */ | |
740 | page_add_new_anon_rmap(page, vma, haddr); | |
741 | set_pmd_at(mm, haddr, pmd, entry); | |
e3ebcf64 | 742 | pgtable_trans_huge_deposit(mm, pgtable); |
71e3aac0 | 743 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
1c641e84 | 744 | mm->nr_ptes++; |
71e3aac0 AA |
745 | spin_unlock(&mm->page_table_lock); |
746 | } | |
747 | ||
aa2e878e | 748 | return 0; |
71e3aac0 AA |
749 | } |
750 | ||
cc5d462f | 751 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 752 | { |
cc5d462f | 753 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
754 | } |
755 | ||
756 | static inline struct page *alloc_hugepage_vma(int defrag, | |
757 | struct vm_area_struct *vma, | |
cc5d462f AK |
758 | unsigned long haddr, int nd, |
759 | gfp_t extra_gfp) | |
0bbbc0b3 | 760 | { |
cc5d462f | 761 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 762 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
763 | } |
764 | ||
765 | #ifndef CONFIG_NUMA | |
71e3aac0 AA |
766 | static inline struct page *alloc_hugepage(int defrag) |
767 | { | |
cc5d462f | 768 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), |
71e3aac0 AA |
769 | HPAGE_PMD_ORDER); |
770 | } | |
0bbbc0b3 | 771 | #endif |
71e3aac0 | 772 | |
3ea41e62 | 773 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 KS |
774 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
775 | unsigned long zero_pfn) | |
fc9fe822 KS |
776 | { |
777 | pmd_t entry; | |
3ea41e62 KS |
778 | if (!pmd_none(*pmd)) |
779 | return false; | |
97ae1749 | 780 | entry = pfn_pmd(zero_pfn, vma->vm_page_prot); |
fc9fe822 KS |
781 | entry = pmd_wrprotect(entry); |
782 | entry = pmd_mkhuge(entry); | |
783 | set_pmd_at(mm, haddr, pmd, entry); | |
784 | pgtable_trans_huge_deposit(mm, pgtable); | |
785 | mm->nr_ptes++; | |
3ea41e62 | 786 | return true; |
fc9fe822 KS |
787 | } |
788 | ||
71e3aac0 AA |
789 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
790 | unsigned long address, pmd_t *pmd, | |
791 | unsigned int flags) | |
792 | { | |
793 | struct page *page; | |
794 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
795 | pte_t *pte; | |
796 | ||
797 | if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { | |
798 | if (unlikely(anon_vma_prepare(vma))) | |
799 | return VM_FAULT_OOM; | |
ba76149f AA |
800 | if (unlikely(khugepaged_enter(vma))) |
801 | return VM_FAULT_OOM; | |
79da5407 KS |
802 | if (!(flags & FAULT_FLAG_WRITE) && |
803 | transparent_hugepage_use_zero_page()) { | |
80371957 | 804 | pgtable_t pgtable; |
97ae1749 | 805 | unsigned long zero_pfn; |
3ea41e62 | 806 | bool set; |
80371957 KS |
807 | pgtable = pte_alloc_one(mm, haddr); |
808 | if (unlikely(!pgtable)) | |
809 | return VM_FAULT_OOM; | |
97ae1749 KS |
810 | zero_pfn = get_huge_zero_page(); |
811 | if (unlikely(!zero_pfn)) { | |
812 | pte_free(mm, pgtable); | |
813 | count_vm_event(THP_FAULT_FALLBACK); | |
814 | goto out; | |
815 | } | |
80371957 | 816 | spin_lock(&mm->page_table_lock); |
3ea41e62 | 817 | set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, |
97ae1749 | 818 | zero_pfn); |
80371957 | 819 | spin_unlock(&mm->page_table_lock); |
3ea41e62 KS |
820 | if (!set) { |
821 | pte_free(mm, pgtable); | |
822 | put_huge_zero_page(); | |
823 | } | |
80371957 KS |
824 | return 0; |
825 | } | |
0bbbc0b3 | 826 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 827 | vma, haddr, numa_node_id(), 0); |
81ab4201 AK |
828 | if (unlikely(!page)) { |
829 | count_vm_event(THP_FAULT_FALLBACK); | |
71e3aac0 | 830 | goto out; |
81ab4201 AK |
831 | } |
832 | count_vm_event(THP_FAULT_ALLOC); | |
b9bbfbe3 AA |
833 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
834 | put_page(page); | |
835 | goto out; | |
836 | } | |
edad9d2c DR |
837 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, |
838 | page))) { | |
839 | mem_cgroup_uncharge_page(page); | |
840 | put_page(page); | |
841 | goto out; | |
842 | } | |
71e3aac0 | 843 | |
edad9d2c | 844 | return 0; |
71e3aac0 AA |
845 | } |
846 | out: | |
847 | /* | |
848 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
849 | * run pte_offset_map on the pmd, if an huge pmd could | |
850 | * materialize from under us from a different thread. | |
851 | */ | |
4fd01770 MG |
852 | if (unlikely(pmd_none(*pmd)) && |
853 | unlikely(__pte_alloc(mm, vma, pmd, address))) | |
71e3aac0 AA |
854 | return VM_FAULT_OOM; |
855 | /* if an huge pmd materialized from under us just retry later */ | |
856 | if (unlikely(pmd_trans_huge(*pmd))) | |
857 | return 0; | |
858 | /* | |
859 | * A regular pmd is established and it can't morph into a huge pmd | |
860 | * from under us anymore at this point because we hold the mmap_sem | |
861 | * read mode and khugepaged takes it in write mode. So now it's | |
862 | * safe to run pte_offset_map(). | |
863 | */ | |
864 | pte = pte_offset_map(pmd, address); | |
865 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); | |
866 | } | |
867 | ||
868 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
869 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
870 | struct vm_area_struct *vma) | |
871 | { | |
872 | struct page *src_page; | |
873 | pmd_t pmd; | |
874 | pgtable_t pgtable; | |
875 | int ret; | |
876 | ||
877 | ret = -ENOMEM; | |
878 | pgtable = pte_alloc_one(dst_mm, addr); | |
879 | if (unlikely(!pgtable)) | |
880 | goto out; | |
881 | ||
882 | spin_lock(&dst_mm->page_table_lock); | |
883 | spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); | |
884 | ||
885 | ret = -EAGAIN; | |
886 | pmd = *src_pmd; | |
887 | if (unlikely(!pmd_trans_huge(pmd))) { | |
888 | pte_free(dst_mm, pgtable); | |
889 | goto out_unlock; | |
890 | } | |
fc9fe822 KS |
891 | /* |
892 | * mm->page_table_lock is enough to be sure that huge zero pmd is not | |
893 | * under splitting since we don't split the page itself, only pmd to | |
894 | * a page table. | |
895 | */ | |
896 | if (is_huge_zero_pmd(pmd)) { | |
97ae1749 | 897 | unsigned long zero_pfn; |
3ea41e62 | 898 | bool set; |
97ae1749 KS |
899 | /* |
900 | * get_huge_zero_page() will never allocate a new page here, | |
901 | * since we already have a zero page to copy. It just takes a | |
902 | * reference. | |
903 | */ | |
904 | zero_pfn = get_huge_zero_page(); | |
3ea41e62 | 905 | set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
97ae1749 | 906 | zero_pfn); |
3ea41e62 | 907 | BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ |
fc9fe822 KS |
908 | ret = 0; |
909 | goto out_unlock; | |
910 | } | |
71e3aac0 AA |
911 | if (unlikely(pmd_trans_splitting(pmd))) { |
912 | /* split huge page running from under us */ | |
913 | spin_unlock(&src_mm->page_table_lock); | |
914 | spin_unlock(&dst_mm->page_table_lock); | |
915 | pte_free(dst_mm, pgtable); | |
916 | ||
917 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
918 | goto out; | |
919 | } | |
920 | src_page = pmd_page(pmd); | |
921 | VM_BUG_ON(!PageHead(src_page)); | |
922 | get_page(src_page); | |
923 | page_dup_rmap(src_page); | |
924 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
925 | ||
926 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
927 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
928 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
e3ebcf64 | 929 | pgtable_trans_huge_deposit(dst_mm, pgtable); |
1c641e84 | 930 | dst_mm->nr_ptes++; |
71e3aac0 AA |
931 | |
932 | ret = 0; | |
933 | out_unlock: | |
934 | spin_unlock(&src_mm->page_table_lock); | |
935 | spin_unlock(&dst_mm->page_table_lock); | |
936 | out: | |
937 | return ret; | |
938 | } | |
939 | ||
a1dd450b WD |
940 | void huge_pmd_set_accessed(struct mm_struct *mm, |
941 | struct vm_area_struct *vma, | |
942 | unsigned long address, | |
943 | pmd_t *pmd, pmd_t orig_pmd, | |
944 | int dirty) | |
945 | { | |
946 | pmd_t entry; | |
947 | unsigned long haddr; | |
948 | ||
949 | spin_lock(&mm->page_table_lock); | |
950 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
951 | goto unlock; | |
952 | ||
953 | entry = pmd_mkyoung(orig_pmd); | |
954 | haddr = address & HPAGE_PMD_MASK; | |
955 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
956 | update_mmu_cache_pmd(vma, address, pmd); | |
957 | ||
958 | unlock: | |
959 | spin_unlock(&mm->page_table_lock); | |
960 | } | |
961 | ||
93b4796d KS |
962 | static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, |
963 | struct vm_area_struct *vma, unsigned long address, | |
3ea41e62 | 964 | pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr) |
93b4796d KS |
965 | { |
966 | pgtable_t pgtable; | |
967 | pmd_t _pmd; | |
968 | struct page *page; | |
969 | int i, ret = 0; | |
970 | unsigned long mmun_start; /* For mmu_notifiers */ | |
971 | unsigned long mmun_end; /* For mmu_notifiers */ | |
972 | ||
973 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
974 | if (!page) { | |
975 | ret |= VM_FAULT_OOM; | |
976 | goto out; | |
977 | } | |
978 | ||
979 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { | |
980 | put_page(page); | |
981 | ret |= VM_FAULT_OOM; | |
982 | goto out; | |
983 | } | |
984 | ||
985 | clear_user_highpage(page, address); | |
986 | __SetPageUptodate(page); | |
987 | ||
988 | mmun_start = haddr; | |
989 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
990 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
991 | ||
992 | spin_lock(&mm->page_table_lock); | |
3ea41e62 KS |
993 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
994 | goto out_free_page; | |
995 | ||
93b4796d KS |
996 | pmdp_clear_flush(vma, haddr, pmd); |
997 | /* leave pmd empty until pte is filled */ | |
998 | ||
999 | pgtable = pgtable_trans_huge_withdraw(mm); | |
1000 | pmd_populate(mm, &_pmd, pgtable); | |
1001 | ||
1002 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1003 | pte_t *pte, entry; | |
1004 | if (haddr == (address & PAGE_MASK)) { | |
1005 | entry = mk_pte(page, vma->vm_page_prot); | |
1006 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1007 | page_add_new_anon_rmap(page, vma, haddr); | |
1008 | } else { | |
1009 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
1010 | entry = pte_mkspecial(entry); | |
1011 | } | |
1012 | pte = pte_offset_map(&_pmd, haddr); | |
1013 | VM_BUG_ON(!pte_none(*pte)); | |
1014 | set_pte_at(mm, haddr, pte, entry); | |
1015 | pte_unmap(pte); | |
1016 | } | |
1017 | smp_wmb(); /* make pte visible before pmd */ | |
1018 | pmd_populate(mm, pmd, pgtable); | |
1019 | spin_unlock(&mm->page_table_lock); | |
97ae1749 | 1020 | put_huge_zero_page(); |
93b4796d KS |
1021 | inc_mm_counter(mm, MM_ANONPAGES); |
1022 | ||
1023 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1024 | ||
1025 | ret |= VM_FAULT_WRITE; | |
1026 | out: | |
1027 | return ret; | |
3ea41e62 KS |
1028 | out_free_page: |
1029 | spin_unlock(&mm->page_table_lock); | |
1030 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1031 | mem_cgroup_uncharge_page(page); | |
1032 | put_page(page); | |
1033 | goto out; | |
93b4796d KS |
1034 | } |
1035 | ||
71e3aac0 AA |
1036 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
1037 | struct vm_area_struct *vma, | |
1038 | unsigned long address, | |
1039 | pmd_t *pmd, pmd_t orig_pmd, | |
1040 | struct page *page, | |
1041 | unsigned long haddr) | |
1042 | { | |
1043 | pgtable_t pgtable; | |
1044 | pmd_t _pmd; | |
1045 | int ret = 0, i; | |
1046 | struct page **pages; | |
2ec74c3e SG |
1047 | unsigned long mmun_start; /* For mmu_notifiers */ |
1048 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1049 | |
1050 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1051 | GFP_KERNEL); | |
1052 | if (unlikely(!pages)) { | |
1053 | ret |= VM_FAULT_OOM; | |
1054 | goto out; | |
1055 | } | |
1056 | ||
1057 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
1058 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
1059 | __GFP_OTHER_NODE, | |
19ee151e | 1060 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
1061 | if (unlikely(!pages[i] || |
1062 | mem_cgroup_newpage_charge(pages[i], mm, | |
1063 | GFP_KERNEL))) { | |
1064 | if (pages[i]) | |
71e3aac0 | 1065 | put_page(pages[i]); |
b9bbfbe3 AA |
1066 | mem_cgroup_uncharge_start(); |
1067 | while (--i >= 0) { | |
1068 | mem_cgroup_uncharge_page(pages[i]); | |
1069 | put_page(pages[i]); | |
1070 | } | |
1071 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1072 | kfree(pages); |
1073 | ret |= VM_FAULT_OOM; | |
1074 | goto out; | |
1075 | } | |
1076 | } | |
1077 | ||
1078 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1079 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1080 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1081 | __SetPageUptodate(pages[i]); |
1082 | cond_resched(); | |
1083 | } | |
1084 | ||
2ec74c3e SG |
1085 | mmun_start = haddr; |
1086 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1087 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1088 | ||
71e3aac0 AA |
1089 | spin_lock(&mm->page_table_lock); |
1090 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1091 | goto out_free_pages; | |
1092 | VM_BUG_ON(!PageHead(page)); | |
1093 | ||
2ec74c3e | 1094 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1095 | /* leave pmd empty until pte is filled */ |
1096 | ||
e3ebcf64 | 1097 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1098 | pmd_populate(mm, &_pmd, pgtable); |
1099 | ||
1100 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1101 | pte_t *pte, entry; | |
1102 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
1103 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1104 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
1105 | pte = pte_offset_map(&_pmd, haddr); | |
1106 | VM_BUG_ON(!pte_none(*pte)); | |
1107 | set_pte_at(mm, haddr, pte, entry); | |
1108 | pte_unmap(pte); | |
1109 | } | |
1110 | kfree(pages); | |
1111 | ||
71e3aac0 AA |
1112 | smp_wmb(); /* make pte visible before pmd */ |
1113 | pmd_populate(mm, pmd, pgtable); | |
1114 | page_remove_rmap(page); | |
1115 | spin_unlock(&mm->page_table_lock); | |
1116 | ||
2ec74c3e SG |
1117 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1118 | ||
71e3aac0 AA |
1119 | ret |= VM_FAULT_WRITE; |
1120 | put_page(page); | |
1121 | ||
1122 | out: | |
1123 | return ret; | |
1124 | ||
1125 | out_free_pages: | |
1126 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1127 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1128 | mem_cgroup_uncharge_start(); |
1129 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1130 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1131 | put_page(pages[i]); |
b9bbfbe3 AA |
1132 | } |
1133 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1134 | kfree(pages); |
1135 | goto out; | |
1136 | } | |
1137 | ||
1138 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1139 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1140 | { | |
1141 | int ret = 0; | |
93b4796d | 1142 | struct page *page = NULL, *new_page; |
71e3aac0 | 1143 | unsigned long haddr; |
2ec74c3e SG |
1144 | unsigned long mmun_start; /* For mmu_notifiers */ |
1145 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1146 | |
1147 | VM_BUG_ON(!vma->anon_vma); | |
93b4796d KS |
1148 | haddr = address & HPAGE_PMD_MASK; |
1149 | if (is_huge_zero_pmd(orig_pmd)) | |
1150 | goto alloc; | |
71e3aac0 AA |
1151 | spin_lock(&mm->page_table_lock); |
1152 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1153 | goto out_unlock; | |
1154 | ||
1155 | page = pmd_page(orig_pmd); | |
1156 | VM_BUG_ON(!PageCompound(page) || !PageHead(page)); | |
71e3aac0 AA |
1157 | if (page_mapcount(page) == 1) { |
1158 | pmd_t entry; | |
1159 | entry = pmd_mkyoung(orig_pmd); | |
1160 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1161 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1162 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1163 | ret |= VM_FAULT_WRITE; |
1164 | goto out_unlock; | |
1165 | } | |
1166 | get_page(page); | |
1167 | spin_unlock(&mm->page_table_lock); | |
93b4796d | 1168 | alloc: |
71e3aac0 AA |
1169 | if (transparent_hugepage_enabled(vma) && |
1170 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1171 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1172 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1173 | else |
1174 | new_page = NULL; | |
1175 | ||
1176 | if (unlikely(!new_page)) { | |
81ab4201 | 1177 | count_vm_event(THP_FAULT_FALLBACK); |
93b4796d KS |
1178 | if (is_huge_zero_pmd(orig_pmd)) { |
1179 | ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, | |
3ea41e62 | 1180 | address, pmd, orig_pmd, haddr); |
93b4796d KS |
1181 | } else { |
1182 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1183 | pmd, orig_pmd, page, haddr); | |
1184 | if (ret & VM_FAULT_OOM) | |
1185 | split_huge_page(page); | |
1186 | put_page(page); | |
1187 | } | |
71e3aac0 AA |
1188 | goto out; |
1189 | } | |
81ab4201 | 1190 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 | 1191 | |
b9bbfbe3 AA |
1192 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1193 | put_page(new_page); | |
93b4796d KS |
1194 | if (page) { |
1195 | split_huge_page(page); | |
1196 | put_page(page); | |
1197 | } | |
b9bbfbe3 AA |
1198 | ret |= VM_FAULT_OOM; |
1199 | goto out; | |
1200 | } | |
1201 | ||
93b4796d KS |
1202 | if (is_huge_zero_pmd(orig_pmd)) |
1203 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); | |
1204 | else | |
1205 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1206 | __SetPageUptodate(new_page); |
1207 | ||
2ec74c3e SG |
1208 | mmun_start = haddr; |
1209 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1210 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1211 | ||
71e3aac0 | 1212 | spin_lock(&mm->page_table_lock); |
93b4796d KS |
1213 | if (page) |
1214 | put_page(page); | |
b9bbfbe3 | 1215 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
6f60b69d | 1216 | spin_unlock(&mm->page_table_lock); |
b9bbfbe3 | 1217 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1218 | put_page(new_page); |
2ec74c3e | 1219 | goto out_mn; |
b9bbfbe3 | 1220 | } else { |
71e3aac0 | 1221 | pmd_t entry; |
b3092b3b | 1222 | entry = mk_huge_pmd(new_page, vma); |
2ec74c3e | 1223 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1224 | page_add_new_anon_rmap(new_page, vma, haddr); |
1225 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1226 | update_mmu_cache_pmd(vma, address, pmd); |
97ae1749 | 1227 | if (is_huge_zero_pmd(orig_pmd)) { |
93b4796d | 1228 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 KS |
1229 | put_huge_zero_page(); |
1230 | } else { | |
93b4796d KS |
1231 | VM_BUG_ON(!PageHead(page)); |
1232 | page_remove_rmap(page); | |
1233 | put_page(page); | |
1234 | } | |
71e3aac0 AA |
1235 | ret |= VM_FAULT_WRITE; |
1236 | } | |
71e3aac0 | 1237 | spin_unlock(&mm->page_table_lock); |
2ec74c3e SG |
1238 | out_mn: |
1239 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1240 | out: |
1241 | return ret; | |
2ec74c3e SG |
1242 | out_unlock: |
1243 | spin_unlock(&mm->page_table_lock); | |
1244 | return ret; | |
71e3aac0 AA |
1245 | } |
1246 | ||
b676b293 | 1247 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1248 | unsigned long addr, |
1249 | pmd_t *pmd, | |
1250 | unsigned int flags) | |
1251 | { | |
b676b293 | 1252 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1253 | struct page *page = NULL; |
1254 | ||
1255 | assert_spin_locked(&mm->page_table_lock); | |
1256 | ||
1257 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1258 | goto out; | |
1259 | ||
1260 | page = pmd_page(*pmd); | |
1261 | VM_BUG_ON(!PageHead(page)); | |
1262 | if (flags & FOLL_TOUCH) { | |
1263 | pmd_t _pmd; | |
1264 | /* | |
1265 | * We should set the dirty bit only for FOLL_WRITE but | |
1266 | * for now the dirty bit in the pmd is meaningless. | |
1267 | * And if the dirty bit will become meaningful and | |
1268 | * we'll only set it with FOLL_WRITE, an atomic | |
1269 | * set_bit will be required on the pmd to set the | |
1270 | * young bit, instead of the current set_pmd_at. | |
1271 | */ | |
1272 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
1273 | set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); | |
1274 | } | |
b676b293 DR |
1275 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1276 | if (page->mapping && trylock_page(page)) { | |
1277 | lru_add_drain(); | |
1278 | if (page->mapping) | |
1279 | mlock_vma_page(page); | |
1280 | unlock_page(page); | |
1281 | } | |
1282 | } | |
71e3aac0 AA |
1283 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
1284 | VM_BUG_ON(!PageCompound(page)); | |
1285 | if (flags & FOLL_GET) | |
70b50f94 | 1286 | get_page_foll(page); |
71e3aac0 AA |
1287 | |
1288 | out: | |
1289 | return page; | |
1290 | } | |
1291 | ||
d10e63f2 | 1292 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1293 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1294 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1295 | { |
b32967ff | 1296 | struct page *page; |
d10e63f2 | 1297 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
4daae3b4 | 1298 | int target_nid; |
03c5a6e1 | 1299 | int current_nid = -1; |
b32967ff MG |
1300 | bool migrated; |
1301 | bool page_locked = false; | |
d10e63f2 MG |
1302 | |
1303 | spin_lock(&mm->page_table_lock); | |
1304 | if (unlikely(!pmd_same(pmd, *pmdp))) | |
1305 | goto out_unlock; | |
1306 | ||
1307 | page = pmd_page(pmd); | |
4daae3b4 | 1308 | get_page(page); |
03c5a6e1 MG |
1309 | current_nid = page_to_nid(page); |
1310 | count_vm_numa_event(NUMA_HINT_FAULTS); | |
1311 | if (current_nid == numa_node_id()) | |
1312 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); | |
4daae3b4 MG |
1313 | |
1314 | target_nid = mpol_misplaced(page, vma, haddr); | |
b32967ff MG |
1315 | if (target_nid == -1) { |
1316 | put_page(page); | |
4daae3b4 | 1317 | goto clear_pmdnuma; |
b32967ff | 1318 | } |
4daae3b4 | 1319 | |
b32967ff MG |
1320 | /* Acquire the page lock to serialise THP migrations */ |
1321 | spin_unlock(&mm->page_table_lock); | |
1322 | lock_page(page); | |
1323 | page_locked = true; | |
4daae3b4 | 1324 | |
b32967ff | 1325 | /* Confirm the PTE did not while locked */ |
4daae3b4 | 1326 | spin_lock(&mm->page_table_lock); |
b32967ff MG |
1327 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1328 | unlock_page(page); | |
1329 | put_page(page); | |
4daae3b4 | 1330 | goto out_unlock; |
b32967ff MG |
1331 | } |
1332 | spin_unlock(&mm->page_table_lock); | |
4daae3b4 | 1333 | |
b32967ff MG |
1334 | /* Migrate the THP to the requested node */ |
1335 | migrated = migrate_misplaced_transhuge_page(mm, vma, | |
1336 | pmdp, pmd, addr, | |
1337 | page, target_nid); | |
1338 | if (migrated) | |
1339 | current_nid = target_nid; | |
1340 | else { | |
1341 | spin_lock(&mm->page_table_lock); | |
1342 | if (unlikely(!pmd_same(pmd, *pmdp))) { | |
1343 | unlock_page(page); | |
1344 | goto out_unlock; | |
1345 | } | |
1346 | goto clear_pmdnuma; | |
1347 | } | |
1348 | ||
1349 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
1350 | return 0; | |
1351 | ||
1352 | clear_pmdnuma: | |
d10e63f2 MG |
1353 | pmd = pmd_mknonnuma(pmd); |
1354 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1355 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1356 | update_mmu_cache_pmd(vma, addr, pmdp); | |
b32967ff MG |
1357 | if (page_locked) |
1358 | unlock_page(page); | |
d10e63f2 MG |
1359 | |
1360 | out_unlock: | |
1361 | spin_unlock(&mm->page_table_lock); | |
b32967ff MG |
1362 | if (current_nid != -1) |
1363 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
d10e63f2 MG |
1364 | return 0; |
1365 | } | |
1366 | ||
71e3aac0 | 1367 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1368 | pmd_t *pmd, unsigned long addr) |
71e3aac0 AA |
1369 | { |
1370 | int ret = 0; | |
1371 | ||
025c5b24 NH |
1372 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1373 | struct page *page; | |
1374 | pgtable_t pgtable; | |
f5c8ad47 | 1375 | pmd_t orig_pmd; |
e3ebcf64 | 1376 | pgtable = pgtable_trans_huge_withdraw(tlb->mm); |
f5c8ad47 | 1377 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1378 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
479f0abb KS |
1379 | if (is_huge_zero_pmd(orig_pmd)) { |
1380 | tlb->mm->nr_ptes--; | |
1381 | spin_unlock(&tlb->mm->page_table_lock); | |
97ae1749 | 1382 | put_huge_zero_page(); |
479f0abb KS |
1383 | } else { |
1384 | page = pmd_page(orig_pmd); | |
1385 | page_remove_rmap(page); | |
1386 | VM_BUG_ON(page_mapcount(page) < 0); | |
1387 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1388 | VM_BUG_ON(!PageHead(page)); | |
1389 | tlb->mm->nr_ptes--; | |
1390 | spin_unlock(&tlb->mm->page_table_lock); | |
1391 | tlb_remove_page(tlb, page); | |
1392 | } | |
025c5b24 NH |
1393 | pte_free(tlb->mm, pgtable); |
1394 | ret = 1; | |
1395 | } | |
71e3aac0 AA |
1396 | return ret; |
1397 | } | |
1398 | ||
0ca1634d JW |
1399 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1400 | unsigned long addr, unsigned long end, | |
1401 | unsigned char *vec) | |
1402 | { | |
1403 | int ret = 0; | |
1404 | ||
025c5b24 NH |
1405 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1406 | /* | |
1407 | * All logical pages in the range are present | |
1408 | * if backed by a huge page. | |
1409 | */ | |
0ca1634d | 1410 | spin_unlock(&vma->vm_mm->page_table_lock); |
025c5b24 NH |
1411 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1412 | ret = 1; | |
1413 | } | |
0ca1634d JW |
1414 | |
1415 | return ret; | |
1416 | } | |
1417 | ||
37a1c49a AA |
1418 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1419 | unsigned long old_addr, | |
1420 | unsigned long new_addr, unsigned long old_end, | |
1421 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1422 | { | |
1423 | int ret = 0; | |
1424 | pmd_t pmd; | |
1425 | ||
1426 | struct mm_struct *mm = vma->vm_mm; | |
1427 | ||
1428 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1429 | (new_addr & ~HPAGE_PMD_MASK) || | |
1430 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1431 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1432 | goto out; | |
1433 | ||
1434 | /* | |
1435 | * The destination pmd shouldn't be established, free_pgtables() | |
1436 | * should have release it. | |
1437 | */ | |
1438 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1439 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1440 | goto out; | |
1441 | } | |
1442 | ||
025c5b24 NH |
1443 | ret = __pmd_trans_huge_lock(old_pmd, vma); |
1444 | if (ret == 1) { | |
1445 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); | |
1446 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
1447 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
37a1c49a AA |
1448 | spin_unlock(&mm->page_table_lock); |
1449 | } | |
1450 | out: | |
1451 | return ret; | |
1452 | } | |
1453 | ||
cd7548ab | 1454 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1455 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1456 | { |
1457 | struct mm_struct *mm = vma->vm_mm; | |
1458 | int ret = 0; | |
1459 | ||
025c5b24 NH |
1460 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1461 | pmd_t entry; | |
1462 | entry = pmdp_get_and_clear(mm, addr, pmd); | |
a4f1de17 | 1463 | if (!prot_numa) { |
4b10e7d5 | 1464 | entry = pmd_modify(entry, newprot); |
a4f1de17 HD |
1465 | BUG_ON(pmd_write(entry)); |
1466 | } else { | |
4b10e7d5 MG |
1467 | struct page *page = pmd_page(*pmd); |
1468 | ||
1469 | /* only check non-shared pages */ | |
1470 | if (page_mapcount(page) == 1 && | |
1471 | !pmd_numa(*pmd)) { | |
1472 | entry = pmd_mknuma(entry); | |
1473 | } | |
1474 | } | |
025c5b24 NH |
1475 | set_pmd_at(mm, addr, pmd, entry); |
1476 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1477 | ret = 1; | |
1478 | } | |
1479 | ||
1480 | return ret; | |
1481 | } | |
1482 | ||
1483 | /* | |
1484 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1485 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1486 | * | |
1487 | * Note that if it returns 1, this routine returns without unlocking page | |
1488 | * table locks. So callers must unlock them. | |
1489 | */ | |
1490 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) | |
1491 | { | |
1492 | spin_lock(&vma->vm_mm->page_table_lock); | |
cd7548ab JW |
1493 | if (likely(pmd_trans_huge(*pmd))) { |
1494 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
025c5b24 | 1495 | spin_unlock(&vma->vm_mm->page_table_lock); |
cd7548ab | 1496 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1497 | return -1; |
cd7548ab | 1498 | } else { |
025c5b24 NH |
1499 | /* Thp mapped by 'pmd' is stable, so we can |
1500 | * handle it as it is. */ | |
1501 | return 1; | |
cd7548ab | 1502 | } |
025c5b24 NH |
1503 | } |
1504 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1505 | return 0; | |
cd7548ab JW |
1506 | } |
1507 | ||
71e3aac0 AA |
1508 | pmd_t *page_check_address_pmd(struct page *page, |
1509 | struct mm_struct *mm, | |
1510 | unsigned long address, | |
1511 | enum page_check_address_pmd_flag flag) | |
1512 | { | |
71e3aac0 AA |
1513 | pmd_t *pmd, *ret = NULL; |
1514 | ||
1515 | if (address & ~HPAGE_PMD_MASK) | |
1516 | goto out; | |
1517 | ||
6219049a BL |
1518 | pmd = mm_find_pmd(mm, address); |
1519 | if (!pmd) | |
71e3aac0 | 1520 | goto out; |
71e3aac0 AA |
1521 | if (pmd_none(*pmd)) |
1522 | goto out; | |
1523 | if (pmd_page(*pmd) != page) | |
1524 | goto out; | |
94fcc585 AA |
1525 | /* |
1526 | * split_vma() may create temporary aliased mappings. There is | |
1527 | * no risk as long as all huge pmd are found and have their | |
1528 | * splitting bit set before __split_huge_page_refcount | |
1529 | * runs. Finding the same huge pmd more than once during the | |
1530 | * same rmap walk is not a problem. | |
1531 | */ | |
1532 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1533 | pmd_trans_splitting(*pmd)) | |
1534 | goto out; | |
71e3aac0 AA |
1535 | if (pmd_trans_huge(*pmd)) { |
1536 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1537 | !pmd_trans_splitting(*pmd)); | |
1538 | ret = pmd; | |
1539 | } | |
1540 | out: | |
1541 | return ret; | |
1542 | } | |
1543 | ||
1544 | static int __split_huge_page_splitting(struct page *page, | |
1545 | struct vm_area_struct *vma, | |
1546 | unsigned long address) | |
1547 | { | |
1548 | struct mm_struct *mm = vma->vm_mm; | |
1549 | pmd_t *pmd; | |
1550 | int ret = 0; | |
2ec74c3e SG |
1551 | /* For mmu_notifiers */ |
1552 | const unsigned long mmun_start = address; | |
1553 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1554 | |
2ec74c3e | 1555 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1556 | spin_lock(&mm->page_table_lock); |
1557 | pmd = page_check_address_pmd(page, mm, address, | |
1558 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); | |
1559 | if (pmd) { | |
1560 | /* | |
1561 | * We can't temporarily set the pmd to null in order | |
1562 | * to split it, the pmd must remain marked huge at all | |
1563 | * times or the VM won't take the pmd_trans_huge paths | |
5a505085 | 1564 | * and it won't wait on the anon_vma->root->rwsem to |
71e3aac0 AA |
1565 | * serialize against split_huge_page*. |
1566 | */ | |
2ec74c3e | 1567 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 AA |
1568 | ret = 1; |
1569 | } | |
1570 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1571 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1572 | |
1573 | return ret; | |
1574 | } | |
1575 | ||
1576 | static void __split_huge_page_refcount(struct page *page) | |
1577 | { | |
1578 | int i; | |
71e3aac0 | 1579 | struct zone *zone = page_zone(page); |
fa9add64 | 1580 | struct lruvec *lruvec; |
70b50f94 | 1581 | int tail_count = 0; |
71e3aac0 AA |
1582 | |
1583 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1584 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1585 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1586 | ||
71e3aac0 | 1587 | compound_lock(page); |
e94c8a9c KH |
1588 | /* complete memcg works before add pages to LRU */ |
1589 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1590 | |
45676885 | 1591 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1592 | struct page *page_tail = page + i; |
1593 | ||
70b50f94 AA |
1594 | /* tail_page->_mapcount cannot change */ |
1595 | BUG_ON(page_mapcount(page_tail) < 0); | |
1596 | tail_count += page_mapcount(page_tail); | |
1597 | /* check for overflow */ | |
1598 | BUG_ON(tail_count < 0); | |
1599 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1600 | /* | |
1601 | * tail_page->_count is zero and not changing from | |
1602 | * under us. But get_page_unless_zero() may be running | |
1603 | * from under us on the tail_page. If we used | |
1604 | * atomic_set() below instead of atomic_add(), we | |
1605 | * would then run atomic_set() concurrently with | |
1606 | * get_page_unless_zero(), and atomic_set() is | |
1607 | * implemented in C not using locked ops. spin_unlock | |
1608 | * on x86 sometime uses locked ops because of PPro | |
1609 | * errata 66, 92, so unless somebody can guarantee | |
1610 | * atomic_set() here would be safe on all archs (and | |
1611 | * not only on x86), it's safer to use atomic_add(). | |
1612 | */ | |
1613 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1614 | &page_tail->_count); | |
71e3aac0 AA |
1615 | |
1616 | /* after clearing PageTail the gup refcount can be released */ | |
1617 | smp_mb(); | |
1618 | ||
a6d30ddd JD |
1619 | /* |
1620 | * retain hwpoison flag of the poisoned tail page: | |
1621 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1622 | * by the memory-failure. | |
1623 | */ | |
1624 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1625 | page_tail->flags |= (page->flags & |
1626 | ((1L << PG_referenced) | | |
1627 | (1L << PG_swapbacked) | | |
1628 | (1L << PG_mlocked) | | |
1629 | (1L << PG_uptodate))); | |
1630 | page_tail->flags |= (1L << PG_dirty); | |
1631 | ||
70b50f94 | 1632 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1633 | smp_wmb(); |
1634 | ||
1635 | /* | |
1636 | * __split_huge_page_splitting() already set the | |
1637 | * splitting bit in all pmd that could map this | |
1638 | * hugepage, that will ensure no CPU can alter the | |
1639 | * mapcount on the head page. The mapcount is only | |
1640 | * accounted in the head page and it has to be | |
1641 | * transferred to all tail pages in the below code. So | |
1642 | * for this code to be safe, the split the mapcount | |
1643 | * can't change. But that doesn't mean userland can't | |
1644 | * keep changing and reading the page contents while | |
1645 | * we transfer the mapcount, so the pmd splitting | |
1646 | * status is achieved setting a reserved bit in the | |
1647 | * pmd, not by clearing the present bit. | |
1648 | */ | |
71e3aac0 AA |
1649 | page_tail->_mapcount = page->_mapcount; |
1650 | ||
1651 | BUG_ON(page_tail->mapping); | |
1652 | page_tail->mapping = page->mapping; | |
1653 | ||
45676885 | 1654 | page_tail->index = page->index + i; |
5aa80374 | 1655 | page_xchg_last_nid(page_tail, page_last_nid(page)); |
71e3aac0 AA |
1656 | |
1657 | BUG_ON(!PageAnon(page_tail)); | |
1658 | BUG_ON(!PageUptodate(page_tail)); | |
1659 | BUG_ON(!PageDirty(page_tail)); | |
1660 | BUG_ON(!PageSwapBacked(page_tail)); | |
1661 | ||
fa9add64 | 1662 | lru_add_page_tail(page, page_tail, lruvec); |
71e3aac0 | 1663 | } |
70b50f94 AA |
1664 | atomic_sub(tail_count, &page->_count); |
1665 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1666 | |
fa9add64 | 1667 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 AA |
1668 | __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); |
1669 | ||
71e3aac0 AA |
1670 | ClearPageCompound(page); |
1671 | compound_unlock(page); | |
1672 | spin_unlock_irq(&zone->lru_lock); | |
1673 | ||
1674 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1675 | struct page *page_tail = page + i; | |
1676 | BUG_ON(page_count(page_tail) <= 0); | |
1677 | /* | |
1678 | * Tail pages may be freed if there wasn't any mapping | |
1679 | * like if add_to_swap() is running on a lru page that | |
1680 | * had its mapping zapped. And freeing these pages | |
1681 | * requires taking the lru_lock so we do the put_page | |
1682 | * of the tail pages after the split is complete. | |
1683 | */ | |
1684 | put_page(page_tail); | |
1685 | } | |
1686 | ||
1687 | /* | |
1688 | * Only the head page (now become a regular page) is required | |
1689 | * to be pinned by the caller. | |
1690 | */ | |
1691 | BUG_ON(page_count(page) <= 0); | |
1692 | } | |
1693 | ||
1694 | static int __split_huge_page_map(struct page *page, | |
1695 | struct vm_area_struct *vma, | |
1696 | unsigned long address) | |
1697 | { | |
1698 | struct mm_struct *mm = vma->vm_mm; | |
1699 | pmd_t *pmd, _pmd; | |
1700 | int ret = 0, i; | |
1701 | pgtable_t pgtable; | |
1702 | unsigned long haddr; | |
1703 | ||
1704 | spin_lock(&mm->page_table_lock); | |
1705 | pmd = page_check_address_pmd(page, mm, address, | |
1706 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); | |
1707 | if (pmd) { | |
e3ebcf64 | 1708 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1709 | pmd_populate(mm, &_pmd, pgtable); |
1710 | ||
e3ebcf64 GS |
1711 | haddr = address; |
1712 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1713 | pte_t *pte, entry; |
1714 | BUG_ON(PageCompound(page+i)); | |
1715 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1716 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1717 | if (!pmd_write(*pmd)) | |
1718 | entry = pte_wrprotect(entry); | |
1719 | else | |
1720 | BUG_ON(page_mapcount(page) != 1); | |
1721 | if (!pmd_young(*pmd)) | |
1722 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1723 | if (pmd_numa(*pmd)) |
1724 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1725 | pte = pte_offset_map(&_pmd, haddr); |
1726 | BUG_ON(!pte_none(*pte)); | |
1727 | set_pte_at(mm, haddr, pte, entry); | |
1728 | pte_unmap(pte); | |
1729 | } | |
1730 | ||
71e3aac0 AA |
1731 | smp_wmb(); /* make pte visible before pmd */ |
1732 | /* | |
1733 | * Up to this point the pmd is present and huge and | |
1734 | * userland has the whole access to the hugepage | |
1735 | * during the split (which happens in place). If we | |
1736 | * overwrite the pmd with the not-huge version | |
1737 | * pointing to the pte here (which of course we could | |
1738 | * if all CPUs were bug free), userland could trigger | |
1739 | * a small page size TLB miss on the small sized TLB | |
1740 | * while the hugepage TLB entry is still established | |
1741 | * in the huge TLB. Some CPU doesn't like that. See | |
1742 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1743 | * Erratum 383 on page 93. Intel should be safe but is | |
1744 | * also warns that it's only safe if the permission | |
1745 | * and cache attributes of the two entries loaded in | |
1746 | * the two TLB is identical (which should be the case | |
1747 | * here). But it is generally safer to never allow | |
1748 | * small and huge TLB entries for the same virtual | |
1749 | * address to be loaded simultaneously. So instead of | |
1750 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1751 | * mark the current pmd notpresent (atomically because | |
1752 | * here the pmd_trans_huge and pmd_trans_splitting | |
1753 | * must remain set at all times on the pmd until the | |
1754 | * split is complete for this pmd), then we flush the | |
1755 | * SMP TLB and finally we write the non-huge version | |
1756 | * of the pmd entry with pmd_populate. | |
1757 | */ | |
46dcde73 | 1758 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1759 | pmd_populate(mm, pmd, pgtable); |
1760 | ret = 1; | |
1761 | } | |
1762 | spin_unlock(&mm->page_table_lock); | |
1763 | ||
1764 | return ret; | |
1765 | } | |
1766 | ||
5a505085 | 1767 | /* must be called with anon_vma->root->rwsem held */ |
71e3aac0 AA |
1768 | static void __split_huge_page(struct page *page, |
1769 | struct anon_vma *anon_vma) | |
1770 | { | |
1771 | int mapcount, mapcount2; | |
bf181b9f | 1772 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1773 | struct anon_vma_chain *avc; |
1774 | ||
1775 | BUG_ON(!PageHead(page)); | |
1776 | BUG_ON(PageTail(page)); | |
1777 | ||
1778 | mapcount = 0; | |
bf181b9f | 1779 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1780 | struct vm_area_struct *vma = avc->vma; |
1781 | unsigned long addr = vma_address(page, vma); | |
1782 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1783 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1784 | } | |
05759d38 AA |
1785 | /* |
1786 | * It is critical that new vmas are added to the tail of the | |
1787 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1788 | * and establishes a child pmd before | |
1789 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1790 | * we fail to prevent copy_huge_pmd() from running until the | |
1791 | * whole __split_huge_page() is complete), we will still see | |
1792 | * the newly established pmd of the child later during the | |
1793 | * walk, to be able to set it as pmd_trans_splitting too. | |
1794 | */ | |
1795 | if (mapcount != page_mapcount(page)) | |
1796 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1797 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1798 | BUG_ON(mapcount != page_mapcount(page)); |
1799 | ||
1800 | __split_huge_page_refcount(page); | |
1801 | ||
1802 | mapcount2 = 0; | |
bf181b9f | 1803 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1804 | struct vm_area_struct *vma = avc->vma; |
1805 | unsigned long addr = vma_address(page, vma); | |
1806 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1807 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1808 | } | |
05759d38 AA |
1809 | if (mapcount != mapcount2) |
1810 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1811 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1812 | BUG_ON(mapcount != mapcount2); |
1813 | } | |
1814 | ||
1815 | int split_huge_page(struct page *page) | |
1816 | { | |
1817 | struct anon_vma *anon_vma; | |
1818 | int ret = 1; | |
1819 | ||
c5a647d0 | 1820 | BUG_ON(is_huge_zero_pfn(page_to_pfn(page))); |
71e3aac0 | 1821 | BUG_ON(!PageAnon(page)); |
4fc3f1d6 | 1822 | anon_vma = page_lock_anon_vma_read(page); |
71e3aac0 AA |
1823 | if (!anon_vma) |
1824 | goto out; | |
1825 | ret = 0; | |
1826 | if (!PageCompound(page)) | |
1827 | goto out_unlock; | |
1828 | ||
1829 | BUG_ON(!PageSwapBacked(page)); | |
1830 | __split_huge_page(page, anon_vma); | |
81ab4201 | 1831 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1832 | |
1833 | BUG_ON(PageCompound(page)); | |
1834 | out_unlock: | |
4fc3f1d6 | 1835 | page_unlock_anon_vma_read(anon_vma); |
71e3aac0 AA |
1836 | out: |
1837 | return ret; | |
1838 | } | |
1839 | ||
4b6e1e37 | 1840 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1841 | |
60ab3244 AA |
1842 | int hugepage_madvise(struct vm_area_struct *vma, |
1843 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1844 | { |
8e72033f GS |
1845 | struct mm_struct *mm = vma->vm_mm; |
1846 | ||
a664b2d8 AA |
1847 | switch (advice) { |
1848 | case MADV_HUGEPAGE: | |
1849 | /* | |
1850 | * Be somewhat over-protective like KSM for now! | |
1851 | */ | |
78f11a25 | 1852 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1853 | return -EINVAL; |
8e72033f GS |
1854 | if (mm->def_flags & VM_NOHUGEPAGE) |
1855 | return -EINVAL; | |
a664b2d8 AA |
1856 | *vm_flags &= ~VM_NOHUGEPAGE; |
1857 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1858 | /* |
1859 | * If the vma become good for khugepaged to scan, | |
1860 | * register it here without waiting a page fault that | |
1861 | * may not happen any time soon. | |
1862 | */ | |
1863 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1864 | return -ENOMEM; | |
a664b2d8 AA |
1865 | break; |
1866 | case MADV_NOHUGEPAGE: | |
1867 | /* | |
1868 | * Be somewhat over-protective like KSM for now! | |
1869 | */ | |
78f11a25 | 1870 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1871 | return -EINVAL; |
1872 | *vm_flags &= ~VM_HUGEPAGE; | |
1873 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1874 | /* |
1875 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1876 | * this vma even if we leave the mm registered in khugepaged if | |
1877 | * it got registered before VM_NOHUGEPAGE was set. | |
1878 | */ | |
a664b2d8 AA |
1879 | break; |
1880 | } | |
0af4e98b AA |
1881 | |
1882 | return 0; | |
1883 | } | |
1884 | ||
ba76149f AA |
1885 | static int __init khugepaged_slab_init(void) |
1886 | { | |
1887 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1888 | sizeof(struct mm_slot), | |
1889 | __alignof__(struct mm_slot), 0, NULL); | |
1890 | if (!mm_slot_cache) | |
1891 | return -ENOMEM; | |
1892 | ||
1893 | return 0; | |
1894 | } | |
1895 | ||
1896 | static void __init khugepaged_slab_free(void) | |
1897 | { | |
1898 | kmem_cache_destroy(mm_slot_cache); | |
1899 | mm_slot_cache = NULL; | |
1900 | } | |
1901 | ||
1902 | static inline struct mm_slot *alloc_mm_slot(void) | |
1903 | { | |
1904 | if (!mm_slot_cache) /* initialization failed */ | |
1905 | return NULL; | |
1906 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1907 | } | |
1908 | ||
1909 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1910 | { | |
1911 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1912 | } | |
1913 | ||
1914 | static int __init mm_slots_hash_init(void) | |
1915 | { | |
1916 | mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head), | |
1917 | GFP_KERNEL); | |
1918 | if (!mm_slots_hash) | |
1919 | return -ENOMEM; | |
1920 | return 0; | |
1921 | } | |
1922 | ||
1923 | #if 0 | |
1924 | static void __init mm_slots_hash_free(void) | |
1925 | { | |
1926 | kfree(mm_slots_hash); | |
1927 | mm_slots_hash = NULL; | |
1928 | } | |
1929 | #endif | |
1930 | ||
1931 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) | |
1932 | { | |
1933 | struct mm_slot *mm_slot; | |
1934 | struct hlist_head *bucket; | |
1935 | struct hlist_node *node; | |
1936 | ||
1937 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1938 | % MM_SLOTS_HASH_HEADS]; | |
1939 | hlist_for_each_entry(mm_slot, node, bucket, hash) { | |
1940 | if (mm == mm_slot->mm) | |
1941 | return mm_slot; | |
1942 | } | |
1943 | return NULL; | |
1944 | } | |
1945 | ||
1946 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1947 | struct mm_slot *mm_slot) | |
1948 | { | |
1949 | struct hlist_head *bucket; | |
1950 | ||
1951 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1952 | % MM_SLOTS_HASH_HEADS]; | |
1953 | mm_slot->mm = mm; | |
1954 | hlist_add_head(&mm_slot->hash, bucket); | |
1955 | } | |
1956 | ||
1957 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1958 | { | |
1959 | return atomic_read(&mm->mm_users) == 0; | |
1960 | } | |
1961 | ||
1962 | int __khugepaged_enter(struct mm_struct *mm) | |
1963 | { | |
1964 | struct mm_slot *mm_slot; | |
1965 | int wakeup; | |
1966 | ||
1967 | mm_slot = alloc_mm_slot(); | |
1968 | if (!mm_slot) | |
1969 | return -ENOMEM; | |
1970 | ||
1971 | /* __khugepaged_exit() must not run from under us */ | |
1972 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1973 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1974 | free_mm_slot(mm_slot); | |
1975 | return 0; | |
1976 | } | |
1977 | ||
1978 | spin_lock(&khugepaged_mm_lock); | |
1979 | insert_to_mm_slots_hash(mm, mm_slot); | |
1980 | /* | |
1981 | * Insert just behind the scanning cursor, to let the area settle | |
1982 | * down a little. | |
1983 | */ | |
1984 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
1985 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
1986 | spin_unlock(&khugepaged_mm_lock); | |
1987 | ||
1988 | atomic_inc(&mm->mm_count); | |
1989 | if (wakeup) | |
1990 | wake_up_interruptible(&khugepaged_wait); | |
1991 | ||
1992 | return 0; | |
1993 | } | |
1994 | ||
1995 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
1996 | { | |
1997 | unsigned long hstart, hend; | |
1998 | if (!vma->anon_vma) | |
1999 | /* | |
2000 | * Not yet faulted in so we will register later in the | |
2001 | * page fault if needed. | |
2002 | */ | |
2003 | return 0; | |
78f11a25 | 2004 | if (vma->vm_ops) |
ba76149f AA |
2005 | /* khugepaged not yet working on file or special mappings */ |
2006 | return 0; | |
b3b9c293 | 2007 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2008 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2009 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2010 | if (hstart < hend) | |
2011 | return khugepaged_enter(vma); | |
2012 | return 0; | |
2013 | } | |
2014 | ||
2015 | void __khugepaged_exit(struct mm_struct *mm) | |
2016 | { | |
2017 | struct mm_slot *mm_slot; | |
2018 | int free = 0; | |
2019 | ||
2020 | spin_lock(&khugepaged_mm_lock); | |
2021 | mm_slot = get_mm_slot(mm); | |
2022 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
2023 | hlist_del(&mm_slot->hash); | |
2024 | list_del(&mm_slot->mm_node); | |
2025 | free = 1; | |
2026 | } | |
d788e80a | 2027 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
2028 | |
2029 | if (free) { | |
ba76149f AA |
2030 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
2031 | free_mm_slot(mm_slot); | |
2032 | mmdrop(mm); | |
2033 | } else if (mm_slot) { | |
ba76149f AA |
2034 | /* |
2035 | * This is required to serialize against | |
2036 | * khugepaged_test_exit() (which is guaranteed to run | |
2037 | * under mmap sem read mode). Stop here (after we | |
2038 | * return all pagetables will be destroyed) until | |
2039 | * khugepaged has finished working on the pagetables | |
2040 | * under the mmap_sem. | |
2041 | */ | |
2042 | down_write(&mm->mmap_sem); | |
2043 | up_write(&mm->mmap_sem); | |
d788e80a | 2044 | } |
ba76149f AA |
2045 | } |
2046 | ||
2047 | static void release_pte_page(struct page *page) | |
2048 | { | |
2049 | /* 0 stands for page_is_file_cache(page) == false */ | |
2050 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2051 | unlock_page(page); | |
2052 | putback_lru_page(page); | |
2053 | } | |
2054 | ||
2055 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
2056 | { | |
2057 | while (--_pte >= pte) { | |
2058 | pte_t pteval = *_pte; | |
2059 | if (!pte_none(pteval)) | |
2060 | release_pte_page(pte_page(pteval)); | |
2061 | } | |
2062 | } | |
2063 | ||
ba76149f AA |
2064 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
2065 | unsigned long address, | |
2066 | pte_t *pte) | |
2067 | { | |
2068 | struct page *page; | |
2069 | pte_t *_pte; | |
344aa35c | 2070 | int referenced = 0, none = 0; |
ba76149f AA |
2071 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
2072 | _pte++, address += PAGE_SIZE) { | |
2073 | pte_t pteval = *_pte; | |
2074 | if (pte_none(pteval)) { | |
2075 | if (++none <= khugepaged_max_ptes_none) | |
2076 | continue; | |
344aa35c | 2077 | else |
ba76149f | 2078 | goto out; |
ba76149f | 2079 | } |
344aa35c | 2080 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 2081 | goto out; |
ba76149f | 2082 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 2083 | if (unlikely(!page)) |
ba76149f | 2084 | goto out; |
344aa35c | 2085 | |
ba76149f AA |
2086 | VM_BUG_ON(PageCompound(page)); |
2087 | BUG_ON(!PageAnon(page)); | |
2088 | VM_BUG_ON(!PageSwapBacked(page)); | |
2089 | ||
2090 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 2091 | if (page_count(page) != 1) |
ba76149f | 2092 | goto out; |
ba76149f AA |
2093 | /* |
2094 | * We can do it before isolate_lru_page because the | |
2095 | * page can't be freed from under us. NOTE: PG_lock | |
2096 | * is needed to serialize against split_huge_page | |
2097 | * when invoked from the VM. | |
2098 | */ | |
344aa35c | 2099 | if (!trylock_page(page)) |
ba76149f | 2100 | goto out; |
ba76149f AA |
2101 | /* |
2102 | * Isolate the page to avoid collapsing an hugepage | |
2103 | * currently in use by the VM. | |
2104 | */ | |
2105 | if (isolate_lru_page(page)) { | |
2106 | unlock_page(page); | |
ba76149f AA |
2107 | goto out; |
2108 | } | |
2109 | /* 0 stands for page_is_file_cache(page) == false */ | |
2110 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2111 | VM_BUG_ON(!PageLocked(page)); | |
2112 | VM_BUG_ON(PageLRU(page)); | |
2113 | ||
2114 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
2115 | if (pte_young(pteval) || PageReferenced(page) || |
2116 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2117 | referenced = 1; |
2118 | } | |
344aa35c BL |
2119 | if (likely(referenced)) |
2120 | return 1; | |
ba76149f | 2121 | out: |
344aa35c BL |
2122 | release_pte_pages(pte, _pte); |
2123 | return 0; | |
ba76149f AA |
2124 | } |
2125 | ||
2126 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
2127 | struct vm_area_struct *vma, | |
2128 | unsigned long address, | |
2129 | spinlock_t *ptl) | |
2130 | { | |
2131 | pte_t *_pte; | |
2132 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
2133 | pte_t pteval = *_pte; | |
2134 | struct page *src_page; | |
2135 | ||
2136 | if (pte_none(pteval)) { | |
2137 | clear_user_highpage(page, address); | |
2138 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
2139 | } else { | |
2140 | src_page = pte_page(pteval); | |
2141 | copy_user_highpage(page, src_page, address, vma); | |
2142 | VM_BUG_ON(page_mapcount(src_page) != 1); | |
ba76149f AA |
2143 | release_pte_page(src_page); |
2144 | /* | |
2145 | * ptl mostly unnecessary, but preempt has to | |
2146 | * be disabled to update the per-cpu stats | |
2147 | * inside page_remove_rmap(). | |
2148 | */ | |
2149 | spin_lock(ptl); | |
2150 | /* | |
2151 | * paravirt calls inside pte_clear here are | |
2152 | * superfluous. | |
2153 | */ | |
2154 | pte_clear(vma->vm_mm, address, _pte); | |
2155 | page_remove_rmap(src_page); | |
2156 | spin_unlock(ptl); | |
2157 | free_page_and_swap_cache(src_page); | |
2158 | } | |
2159 | ||
2160 | address += PAGE_SIZE; | |
2161 | page++; | |
2162 | } | |
2163 | } | |
2164 | ||
26234f36 | 2165 | static void khugepaged_alloc_sleep(void) |
ba76149f | 2166 | { |
26234f36 XG |
2167 | wait_event_freezable_timeout(khugepaged_wait, false, |
2168 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
2169 | } | |
ba76149f | 2170 | |
26234f36 XG |
2171 | #ifdef CONFIG_NUMA |
2172 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2173 | { | |
2174 | if (IS_ERR(*hpage)) { | |
2175 | if (!*wait) | |
2176 | return false; | |
2177 | ||
2178 | *wait = false; | |
e3b4126c | 2179 | *hpage = NULL; |
26234f36 XG |
2180 | khugepaged_alloc_sleep(); |
2181 | } else if (*hpage) { | |
2182 | put_page(*hpage); | |
2183 | *hpage = NULL; | |
2184 | } | |
2185 | ||
2186 | return true; | |
2187 | } | |
2188 | ||
2189 | static struct page | |
2190 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2191 | struct vm_area_struct *vma, unsigned long address, | |
2192 | int node) | |
2193 | { | |
0bbbc0b3 | 2194 | VM_BUG_ON(*hpage); |
ce83d217 AA |
2195 | /* |
2196 | * Allocate the page while the vma is still valid and under | |
2197 | * the mmap_sem read mode so there is no memory allocation | |
2198 | * later when we take the mmap_sem in write mode. This is more | |
2199 | * friendly behavior (OTOH it may actually hide bugs) to | |
2200 | * filesystems in userland with daemons allocating memory in | |
2201 | * the userland I/O paths. Allocating memory with the | |
2202 | * mmap_sem in read mode is good idea also to allow greater | |
2203 | * scalability. | |
2204 | */ | |
26234f36 | 2205 | *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, |
cc5d462f | 2206 | node, __GFP_OTHER_NODE); |
692e0b35 AA |
2207 | |
2208 | /* | |
2209 | * After allocating the hugepage, release the mmap_sem read lock in | |
2210 | * preparation for taking it in write mode. | |
2211 | */ | |
2212 | up_read(&mm->mmap_sem); | |
26234f36 | 2213 | if (unlikely(!*hpage)) { |
81ab4201 | 2214 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2215 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2216 | return NULL; |
ce83d217 | 2217 | } |
26234f36 | 2218 | |
65b3c07b | 2219 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2220 | return *hpage; |
2221 | } | |
2222 | #else | |
2223 | static struct page *khugepaged_alloc_hugepage(bool *wait) | |
2224 | { | |
2225 | struct page *hpage; | |
2226 | ||
2227 | do { | |
2228 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2229 | if (!hpage) { | |
2230 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2231 | if (!*wait) | |
2232 | return NULL; | |
2233 | ||
2234 | *wait = false; | |
2235 | khugepaged_alloc_sleep(); | |
2236 | } else | |
2237 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2238 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2239 | ||
2240 | return hpage; | |
2241 | } | |
2242 | ||
2243 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2244 | { | |
2245 | if (!*hpage) | |
2246 | *hpage = khugepaged_alloc_hugepage(wait); | |
2247 | ||
2248 | if (unlikely(!*hpage)) | |
2249 | return false; | |
2250 | ||
2251 | return true; | |
2252 | } | |
2253 | ||
2254 | static struct page | |
2255 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2256 | struct vm_area_struct *vma, unsigned long address, | |
2257 | int node) | |
2258 | { | |
2259 | up_read(&mm->mmap_sem); | |
2260 | VM_BUG_ON(!*hpage); | |
2261 | return *hpage; | |
2262 | } | |
692e0b35 AA |
2263 | #endif |
2264 | ||
fa475e51 BL |
2265 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2266 | { | |
2267 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2268 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2269 | return false; | |
2270 | ||
2271 | if (!vma->anon_vma || vma->vm_ops) | |
2272 | return false; | |
2273 | if (is_vma_temporary_stack(vma)) | |
2274 | return false; | |
2275 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2276 | return true; | |
2277 | } | |
2278 | ||
26234f36 XG |
2279 | static void collapse_huge_page(struct mm_struct *mm, |
2280 | unsigned long address, | |
2281 | struct page **hpage, | |
2282 | struct vm_area_struct *vma, | |
2283 | int node) | |
2284 | { | |
26234f36 XG |
2285 | pmd_t *pmd, _pmd; |
2286 | pte_t *pte; | |
2287 | pgtable_t pgtable; | |
2288 | struct page *new_page; | |
2289 | spinlock_t *ptl; | |
2290 | int isolated; | |
2291 | unsigned long hstart, hend; | |
2ec74c3e SG |
2292 | unsigned long mmun_start; /* For mmu_notifiers */ |
2293 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2294 | |
2295 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2296 | ||
2297 | /* release the mmap_sem read lock. */ | |
2298 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2299 | if (!new_page) | |
2300 | return; | |
2301 | ||
420256ef | 2302 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2303 | return; |
ba76149f AA |
2304 | |
2305 | /* | |
2306 | * Prevent all access to pagetables with the exception of | |
2307 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2308 | * handled by the anon_vma lock + PG_lock. | |
2309 | */ | |
2310 | down_write(&mm->mmap_sem); | |
2311 | if (unlikely(khugepaged_test_exit(mm))) | |
2312 | goto out; | |
2313 | ||
2314 | vma = find_vma(mm, address); | |
2315 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; | |
2316 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2317 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2318 | goto out; | |
fa475e51 | 2319 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2320 | goto out; |
6219049a BL |
2321 | pmd = mm_find_pmd(mm, address); |
2322 | if (!pmd) | |
ba76149f | 2323 | goto out; |
6219049a | 2324 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2325 | goto out; |
2326 | ||
4fc3f1d6 | 2327 | anon_vma_lock_write(vma->anon_vma); |
ba76149f AA |
2328 | |
2329 | pte = pte_offset_map(pmd, address); | |
2330 | ptl = pte_lockptr(mm, pmd); | |
2331 | ||
2ec74c3e SG |
2332 | mmun_start = address; |
2333 | mmun_end = address + HPAGE_PMD_SIZE; | |
2334 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
ba76149f AA |
2335 | spin_lock(&mm->page_table_lock); /* probably unnecessary */ |
2336 | /* | |
2337 | * After this gup_fast can't run anymore. This also removes | |
2338 | * any huge TLB entry from the CPU so we won't allow | |
2339 | * huge and small TLB entries for the same virtual address | |
2340 | * to avoid the risk of CPU bugs in that area. | |
2341 | */ | |
2ec74c3e | 2342 | _pmd = pmdp_clear_flush(vma, address, pmd); |
ba76149f | 2343 | spin_unlock(&mm->page_table_lock); |
2ec74c3e | 2344 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f AA |
2345 | |
2346 | spin_lock(ptl); | |
2347 | isolated = __collapse_huge_page_isolate(vma, address, pte); | |
2348 | spin_unlock(ptl); | |
ba76149f AA |
2349 | |
2350 | if (unlikely(!isolated)) { | |
453c7192 | 2351 | pte_unmap(pte); |
ba76149f AA |
2352 | spin_lock(&mm->page_table_lock); |
2353 | BUG_ON(!pmd_none(*pmd)); | |
2354 | set_pmd_at(mm, address, pmd, _pmd); | |
2355 | spin_unlock(&mm->page_table_lock); | |
2356 | anon_vma_unlock(vma->anon_vma); | |
ce83d217 | 2357 | goto out; |
ba76149f AA |
2358 | } |
2359 | ||
2360 | /* | |
2361 | * All pages are isolated and locked so anon_vma rmap | |
2362 | * can't run anymore. | |
2363 | */ | |
2364 | anon_vma_unlock(vma->anon_vma); | |
2365 | ||
2366 | __collapse_huge_page_copy(pte, new_page, vma, address, ptl); | |
453c7192 | 2367 | pte_unmap(pte); |
ba76149f AA |
2368 | __SetPageUptodate(new_page); |
2369 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2370 | |
b3092b3b | 2371 | _pmd = mk_huge_pmd(new_page, vma); |
ba76149f AA |
2372 | |
2373 | /* | |
2374 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2375 | * this is needed to avoid the copy_huge_page writes to become | |
2376 | * visible after the set_pmd_at() write. | |
2377 | */ | |
2378 | smp_wmb(); | |
2379 | ||
2380 | spin_lock(&mm->page_table_lock); | |
2381 | BUG_ON(!pmd_none(*pmd)); | |
2382 | page_add_new_anon_rmap(new_page, vma, address); | |
2383 | set_pmd_at(mm, address, pmd, _pmd); | |
b113da65 | 2384 | update_mmu_cache_pmd(vma, address, pmd); |
e3ebcf64 | 2385 | pgtable_trans_huge_deposit(mm, pgtable); |
ba76149f AA |
2386 | spin_unlock(&mm->page_table_lock); |
2387 | ||
2388 | *hpage = NULL; | |
420256ef | 2389 | |
ba76149f | 2390 | khugepaged_pages_collapsed++; |
ce83d217 | 2391 | out_up_write: |
ba76149f | 2392 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2393 | return; |
2394 | ||
ce83d217 | 2395 | out: |
678ff896 | 2396 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2397 | goto out_up_write; |
ba76149f AA |
2398 | } |
2399 | ||
2400 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2401 | struct vm_area_struct *vma, | |
2402 | unsigned long address, | |
2403 | struct page **hpage) | |
2404 | { | |
ba76149f AA |
2405 | pmd_t *pmd; |
2406 | pte_t *pte, *_pte; | |
2407 | int ret = 0, referenced = 0, none = 0; | |
2408 | struct page *page; | |
2409 | unsigned long _address; | |
2410 | spinlock_t *ptl; | |
5c4b4be3 | 2411 | int node = -1; |
ba76149f AA |
2412 | |
2413 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2414 | ||
6219049a BL |
2415 | pmd = mm_find_pmd(mm, address); |
2416 | if (!pmd) | |
ba76149f | 2417 | goto out; |
6219049a | 2418 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2419 | goto out; |
2420 | ||
2421 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2422 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2423 | _pte++, _address += PAGE_SIZE) { | |
2424 | pte_t pteval = *_pte; | |
2425 | if (pte_none(pteval)) { | |
2426 | if (++none <= khugepaged_max_ptes_none) | |
2427 | continue; | |
2428 | else | |
2429 | goto out_unmap; | |
2430 | } | |
2431 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2432 | goto out_unmap; | |
2433 | page = vm_normal_page(vma, _address, pteval); | |
2434 | if (unlikely(!page)) | |
2435 | goto out_unmap; | |
5c4b4be3 AK |
2436 | /* |
2437 | * Chose the node of the first page. This could | |
2438 | * be more sophisticated and look at more pages, | |
2439 | * but isn't for now. | |
2440 | */ | |
2441 | if (node == -1) | |
2442 | node = page_to_nid(page); | |
ba76149f AA |
2443 | VM_BUG_ON(PageCompound(page)); |
2444 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) | |
2445 | goto out_unmap; | |
2446 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2447 | if (page_count(page) != 1) | |
2448 | goto out_unmap; | |
8ee53820 AA |
2449 | if (pte_young(pteval) || PageReferenced(page) || |
2450 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2451 | referenced = 1; |
2452 | } | |
2453 | if (referenced) | |
2454 | ret = 1; | |
2455 | out_unmap: | |
2456 | pte_unmap_unlock(pte, ptl); | |
ce83d217 AA |
2457 | if (ret) |
2458 | /* collapse_huge_page will return with the mmap_sem released */ | |
5c4b4be3 | 2459 | collapse_huge_page(mm, address, hpage, vma, node); |
ba76149f AA |
2460 | out: |
2461 | return ret; | |
2462 | } | |
2463 | ||
2464 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2465 | { | |
2466 | struct mm_struct *mm = mm_slot->mm; | |
2467 | ||
b9980cdc | 2468 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2469 | |
2470 | if (khugepaged_test_exit(mm)) { | |
2471 | /* free mm_slot */ | |
2472 | hlist_del(&mm_slot->hash); | |
2473 | list_del(&mm_slot->mm_node); | |
2474 | ||
2475 | /* | |
2476 | * Not strictly needed because the mm exited already. | |
2477 | * | |
2478 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2479 | */ | |
2480 | ||
2481 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2482 | free_mm_slot(mm_slot); | |
2483 | mmdrop(mm); | |
2484 | } | |
2485 | } | |
2486 | ||
2487 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2488 | struct page **hpage) | |
2f1da642 HS |
2489 | __releases(&khugepaged_mm_lock) |
2490 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2491 | { |
2492 | struct mm_slot *mm_slot; | |
2493 | struct mm_struct *mm; | |
2494 | struct vm_area_struct *vma; | |
2495 | int progress = 0; | |
2496 | ||
2497 | VM_BUG_ON(!pages); | |
b9980cdc | 2498 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2499 | |
2500 | if (khugepaged_scan.mm_slot) | |
2501 | mm_slot = khugepaged_scan.mm_slot; | |
2502 | else { | |
2503 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2504 | struct mm_slot, mm_node); | |
2505 | khugepaged_scan.address = 0; | |
2506 | khugepaged_scan.mm_slot = mm_slot; | |
2507 | } | |
2508 | spin_unlock(&khugepaged_mm_lock); | |
2509 | ||
2510 | mm = mm_slot->mm; | |
2511 | down_read(&mm->mmap_sem); | |
2512 | if (unlikely(khugepaged_test_exit(mm))) | |
2513 | vma = NULL; | |
2514 | else | |
2515 | vma = find_vma(mm, khugepaged_scan.address); | |
2516 | ||
2517 | progress++; | |
2518 | for (; vma; vma = vma->vm_next) { | |
2519 | unsigned long hstart, hend; | |
2520 | ||
2521 | cond_resched(); | |
2522 | if (unlikely(khugepaged_test_exit(mm))) { | |
2523 | progress++; | |
2524 | break; | |
2525 | } | |
fa475e51 BL |
2526 | if (!hugepage_vma_check(vma)) { |
2527 | skip: | |
ba76149f AA |
2528 | progress++; |
2529 | continue; | |
2530 | } | |
ba76149f AA |
2531 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2532 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2533 | if (hstart >= hend) |
2534 | goto skip; | |
2535 | if (khugepaged_scan.address > hend) | |
2536 | goto skip; | |
ba76149f AA |
2537 | if (khugepaged_scan.address < hstart) |
2538 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2539 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2540 | |
2541 | while (khugepaged_scan.address < hend) { | |
2542 | int ret; | |
2543 | cond_resched(); | |
2544 | if (unlikely(khugepaged_test_exit(mm))) | |
2545 | goto breakouterloop; | |
2546 | ||
2547 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2548 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2549 | hend); | |
2550 | ret = khugepaged_scan_pmd(mm, vma, | |
2551 | khugepaged_scan.address, | |
2552 | hpage); | |
2553 | /* move to next address */ | |
2554 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2555 | progress += HPAGE_PMD_NR; | |
2556 | if (ret) | |
2557 | /* we released mmap_sem so break loop */ | |
2558 | goto breakouterloop_mmap_sem; | |
2559 | if (progress >= pages) | |
2560 | goto breakouterloop; | |
2561 | } | |
2562 | } | |
2563 | breakouterloop: | |
2564 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2565 | breakouterloop_mmap_sem: | |
2566 | ||
2567 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2568 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2569 | /* |
2570 | * Release the current mm_slot if this mm is about to die, or | |
2571 | * if we scanned all vmas of this mm. | |
2572 | */ | |
2573 | if (khugepaged_test_exit(mm) || !vma) { | |
2574 | /* | |
2575 | * Make sure that if mm_users is reaching zero while | |
2576 | * khugepaged runs here, khugepaged_exit will find | |
2577 | * mm_slot not pointing to the exiting mm. | |
2578 | */ | |
2579 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2580 | khugepaged_scan.mm_slot = list_entry( | |
2581 | mm_slot->mm_node.next, | |
2582 | struct mm_slot, mm_node); | |
2583 | khugepaged_scan.address = 0; | |
2584 | } else { | |
2585 | khugepaged_scan.mm_slot = NULL; | |
2586 | khugepaged_full_scans++; | |
2587 | } | |
2588 | ||
2589 | collect_mm_slot(mm_slot); | |
2590 | } | |
2591 | ||
2592 | return progress; | |
2593 | } | |
2594 | ||
2595 | static int khugepaged_has_work(void) | |
2596 | { | |
2597 | return !list_empty(&khugepaged_scan.mm_head) && | |
2598 | khugepaged_enabled(); | |
2599 | } | |
2600 | ||
2601 | static int khugepaged_wait_event(void) | |
2602 | { | |
2603 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2604 | kthread_should_stop(); |
ba76149f AA |
2605 | } |
2606 | ||
d516904b | 2607 | static void khugepaged_do_scan(void) |
ba76149f | 2608 | { |
d516904b | 2609 | struct page *hpage = NULL; |
ba76149f AA |
2610 | unsigned int progress = 0, pass_through_head = 0; |
2611 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2612 | bool wait = true; |
ba76149f AA |
2613 | |
2614 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2615 | ||
2616 | while (progress < pages) { | |
26234f36 | 2617 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2618 | break; |
26234f36 | 2619 | |
420256ef | 2620 | cond_resched(); |
ba76149f | 2621 | |
878aee7d AA |
2622 | if (unlikely(kthread_should_stop() || freezing(current))) |
2623 | break; | |
2624 | ||
ba76149f AA |
2625 | spin_lock(&khugepaged_mm_lock); |
2626 | if (!khugepaged_scan.mm_slot) | |
2627 | pass_through_head++; | |
2628 | if (khugepaged_has_work() && | |
2629 | pass_through_head < 2) | |
2630 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2631 | &hpage); |
ba76149f AA |
2632 | else |
2633 | progress = pages; | |
2634 | spin_unlock(&khugepaged_mm_lock); | |
2635 | } | |
ba76149f | 2636 | |
d516904b XG |
2637 | if (!IS_ERR_OR_NULL(hpage)) |
2638 | put_page(hpage); | |
0bbbc0b3 AA |
2639 | } |
2640 | ||
2017c0bf XG |
2641 | static void khugepaged_wait_work(void) |
2642 | { | |
2643 | try_to_freeze(); | |
2644 | ||
2645 | if (khugepaged_has_work()) { | |
2646 | if (!khugepaged_scan_sleep_millisecs) | |
2647 | return; | |
2648 | ||
2649 | wait_event_freezable_timeout(khugepaged_wait, | |
2650 | kthread_should_stop(), | |
2651 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2652 | return; | |
2653 | } | |
2654 | ||
2655 | if (khugepaged_enabled()) | |
2656 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2657 | } | |
2658 | ||
ba76149f AA |
2659 | static int khugepaged(void *none) |
2660 | { | |
2661 | struct mm_slot *mm_slot; | |
2662 | ||
878aee7d | 2663 | set_freezable(); |
ba76149f AA |
2664 | set_user_nice(current, 19); |
2665 | ||
b7231789 XG |
2666 | while (!kthread_should_stop()) { |
2667 | khugepaged_do_scan(); | |
2668 | khugepaged_wait_work(); | |
2669 | } | |
ba76149f AA |
2670 | |
2671 | spin_lock(&khugepaged_mm_lock); | |
2672 | mm_slot = khugepaged_scan.mm_slot; | |
2673 | khugepaged_scan.mm_slot = NULL; | |
2674 | if (mm_slot) | |
2675 | collect_mm_slot(mm_slot); | |
2676 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2677 | return 0; |
2678 | } | |
2679 | ||
c5a647d0 KS |
2680 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2681 | unsigned long haddr, pmd_t *pmd) | |
2682 | { | |
2683 | struct mm_struct *mm = vma->vm_mm; | |
2684 | pgtable_t pgtable; | |
2685 | pmd_t _pmd; | |
2686 | int i; | |
2687 | ||
2688 | pmdp_clear_flush(vma, haddr, pmd); | |
2689 | /* leave pmd empty until pte is filled */ | |
2690 | ||
2691 | pgtable = pgtable_trans_huge_withdraw(mm); | |
2692 | pmd_populate(mm, &_pmd, pgtable); | |
2693 | ||
2694 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2695 | pte_t *pte, entry; | |
2696 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2697 | entry = pte_mkspecial(entry); | |
2698 | pte = pte_offset_map(&_pmd, haddr); | |
2699 | VM_BUG_ON(!pte_none(*pte)); | |
2700 | set_pte_at(mm, haddr, pte, entry); | |
2701 | pte_unmap(pte); | |
2702 | } | |
2703 | smp_wmb(); /* make pte visible before pmd */ | |
2704 | pmd_populate(mm, pmd, pgtable); | |
97ae1749 | 2705 | put_huge_zero_page(); |
c5a647d0 KS |
2706 | } |
2707 | ||
e180377f KS |
2708 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2709 | pmd_t *pmd) | |
71e3aac0 AA |
2710 | { |
2711 | struct page *page; | |
e180377f | 2712 | struct mm_struct *mm = vma->vm_mm; |
c5a647d0 KS |
2713 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2714 | unsigned long mmun_start; /* For mmu_notifiers */ | |
2715 | unsigned long mmun_end; /* For mmu_notifiers */ | |
e180377f KS |
2716 | |
2717 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 | 2718 | |
c5a647d0 KS |
2719 | mmun_start = haddr; |
2720 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
2721 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
2722 | spin_lock(&mm->page_table_lock); |
2723 | if (unlikely(!pmd_trans_huge(*pmd))) { | |
2724 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 KS |
2725 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2726 | return; | |
2727 | } | |
2728 | if (is_huge_zero_pmd(*pmd)) { | |
2729 | __split_huge_zero_page_pmd(vma, haddr, pmd); | |
2730 | spin_unlock(&mm->page_table_lock); | |
2731 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
2732 | return; |
2733 | } | |
2734 | page = pmd_page(*pmd); | |
2735 | VM_BUG_ON(!page_count(page)); | |
2736 | get_page(page); | |
2737 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 | 2738 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2739 | |
2740 | split_huge_page(page); | |
2741 | ||
2742 | put_page(page); | |
2743 | BUG_ON(pmd_trans_huge(*pmd)); | |
2744 | } | |
94fcc585 | 2745 | |
e180377f KS |
2746 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2747 | pmd_t *pmd) | |
2748 | { | |
2749 | struct vm_area_struct *vma; | |
2750 | ||
2751 | vma = find_vma(mm, address); | |
2752 | BUG_ON(vma == NULL); | |
2753 | split_huge_page_pmd(vma, address, pmd); | |
2754 | } | |
2755 | ||
94fcc585 AA |
2756 | static void split_huge_page_address(struct mm_struct *mm, |
2757 | unsigned long address) | |
2758 | { | |
94fcc585 AA |
2759 | pmd_t *pmd; |
2760 | ||
2761 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2762 | ||
6219049a BL |
2763 | pmd = mm_find_pmd(mm, address); |
2764 | if (!pmd) | |
94fcc585 AA |
2765 | return; |
2766 | /* | |
2767 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2768 | * materialize from under us. | |
2769 | */ | |
e180377f | 2770 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2771 | } |
2772 | ||
2773 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2774 | unsigned long start, | |
2775 | unsigned long end, | |
2776 | long adjust_next) | |
2777 | { | |
2778 | /* | |
2779 | * If the new start address isn't hpage aligned and it could | |
2780 | * previously contain an hugepage: check if we need to split | |
2781 | * an huge pmd. | |
2782 | */ | |
2783 | if (start & ~HPAGE_PMD_MASK && | |
2784 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2785 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2786 | split_huge_page_address(vma->vm_mm, start); | |
2787 | ||
2788 | /* | |
2789 | * If the new end address isn't hpage aligned and it could | |
2790 | * previously contain an hugepage: check if we need to split | |
2791 | * an huge pmd. | |
2792 | */ | |
2793 | if (end & ~HPAGE_PMD_MASK && | |
2794 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2795 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2796 | split_huge_page_address(vma->vm_mm, end); | |
2797 | ||
2798 | /* | |
2799 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2800 | * vm_next->vm_start isn't page aligned and it could previously | |
2801 | * contain an hugepage: check if we need to split an huge pmd. | |
2802 | */ | |
2803 | if (adjust_next > 0) { | |
2804 | struct vm_area_struct *next = vma->vm_next; | |
2805 | unsigned long nstart = next->vm_start; | |
2806 | nstart += adjust_next << PAGE_SHIFT; | |
2807 | if (nstart & ~HPAGE_PMD_MASK && | |
2808 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2809 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2810 | split_huge_page_address(next->vm_mm, nstart); | |
2811 | } | |
2812 | } |