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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
8 | #include <linux/mm.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/highmem.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <linux/mmu_notifier.h> | |
13 | #include <linux/rmap.h> | |
14 | #include <linux/swap.h> | |
97ae1749 | 15 | #include <linux/shrinker.h> |
ba76149f AA |
16 | #include <linux/mm_inline.h> |
17 | #include <linux/kthread.h> | |
18 | #include <linux/khugepaged.h> | |
878aee7d | 19 | #include <linux/freezer.h> |
a664b2d8 | 20 | #include <linux/mman.h> |
325adeb5 | 21 | #include <linux/pagemap.h> |
4daae3b4 | 22 | #include <linux/migrate.h> |
43b5fbbd | 23 | #include <linux/hashtable.h> |
97ae1749 | 24 | |
71e3aac0 AA |
25 | #include <asm/tlb.h> |
26 | #include <asm/pgalloc.h> | |
27 | #include "internal.h" | |
28 | ||
ba76149f | 29 | /* |
8bfa3f9a JW |
30 | * By default transparent hugepage support is disabled in order that avoid |
31 | * to risk increase the memory footprint of applications without a guaranteed | |
32 | * benefit. When transparent hugepage support is enabled, is for all mappings, | |
33 | * and khugepaged scans all mappings. | |
34 | * Defrag is invoked by khugepaged hugepage allocations and by page faults | |
35 | * for all hugepage allocations. | |
ba76149f | 36 | */ |
71e3aac0 | 37 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 38 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 39 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
40 | #endif |
41 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
42 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
43 | #endif | |
d39d33c3 | 44 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
79da5407 KS |
45 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
46 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f AA |
47 | |
48 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
49 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
50 | static unsigned int khugepaged_pages_collapsed; | |
51 | static unsigned int khugepaged_full_scans; | |
52 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
53 | /* during fragmentation poll the hugepage allocator once every minute */ | |
54 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
55 | static struct task_struct *khugepaged_thread __read_mostly; | |
56 | static DEFINE_MUTEX(khugepaged_mutex); | |
57 | static DEFINE_SPINLOCK(khugepaged_mm_lock); | |
58 | static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); | |
59 | /* | |
60 | * default collapse hugepages if there is at least one pte mapped like | |
61 | * it would have happened if the vma was large enough during page | |
62 | * fault. | |
63 | */ | |
64 | static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; | |
65 | ||
66 | static int khugepaged(void *none); | |
ba76149f | 67 | static int khugepaged_slab_init(void); |
ba76149f | 68 | |
43b5fbbd SL |
69 | #define MM_SLOTS_HASH_BITS 10 |
70 | static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); | |
71 | ||
ba76149f AA |
72 | static struct kmem_cache *mm_slot_cache __read_mostly; |
73 | ||
74 | /** | |
75 | * struct mm_slot - hash lookup from mm to mm_slot | |
76 | * @hash: hash collision list | |
77 | * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head | |
78 | * @mm: the mm that this information is valid for | |
79 | */ | |
80 | struct mm_slot { | |
81 | struct hlist_node hash; | |
82 | struct list_head mm_node; | |
83 | struct mm_struct *mm; | |
84 | }; | |
85 | ||
86 | /** | |
87 | * struct khugepaged_scan - cursor for scanning | |
88 | * @mm_head: the head of the mm list to scan | |
89 | * @mm_slot: the current mm_slot we are scanning | |
90 | * @address: the next address inside that to be scanned | |
91 | * | |
92 | * There is only the one khugepaged_scan instance of this cursor structure. | |
93 | */ | |
94 | struct khugepaged_scan { | |
95 | struct list_head mm_head; | |
96 | struct mm_slot *mm_slot; | |
97 | unsigned long address; | |
2f1da642 HS |
98 | }; |
99 | static struct khugepaged_scan khugepaged_scan = { | |
ba76149f AA |
100 | .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), |
101 | }; | |
102 | ||
f000565a AA |
103 | |
104 | static int set_recommended_min_free_kbytes(void) | |
105 | { | |
106 | struct zone *zone; | |
107 | int nr_zones = 0; | |
108 | unsigned long recommended_min; | |
f000565a | 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 | 166 | static atomic_t huge_zero_refcount; |
5918d10a | 167 | static struct page *huge_zero_page __read_mostly; |
97ae1749 | 168 | |
5918d10a | 169 | static inline bool is_huge_zero_page(struct page *page) |
4a6c1297 | 170 | { |
5918d10a | 171 | return ACCESS_ONCE(huge_zero_page) == page; |
97ae1749 | 172 | } |
4a6c1297 | 173 | |
97ae1749 KS |
174 | static inline bool is_huge_zero_pmd(pmd_t pmd) |
175 | { | |
5918d10a | 176 | return is_huge_zero_page(pmd_page(pmd)); |
97ae1749 KS |
177 | } |
178 | ||
5918d10a | 179 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
180 | { |
181 | struct page *zero_page; | |
182 | retry: | |
183 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
5918d10a | 184 | return ACCESS_ONCE(huge_zero_page); |
97ae1749 KS |
185 | |
186 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 187 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
188 | if (!zero_page) { |
189 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 190 | return NULL; |
d8a8e1f0 KS |
191 | } |
192 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 193 | preempt_disable(); |
5918d10a | 194 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 KS |
195 | preempt_enable(); |
196 | __free_page(zero_page); | |
197 | goto retry; | |
198 | } | |
199 | ||
200 | /* We take additional reference here. It will be put back by shrinker */ | |
201 | atomic_set(&huge_zero_refcount, 2); | |
202 | preempt_enable(); | |
5918d10a | 203 | return ACCESS_ONCE(huge_zero_page); |
4a6c1297 KS |
204 | } |
205 | ||
97ae1749 | 206 | static void put_huge_zero_page(void) |
4a6c1297 | 207 | { |
97ae1749 KS |
208 | /* |
209 | * Counter should never go to zero here. Only shrinker can put | |
210 | * last reference. | |
211 | */ | |
212 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
213 | } |
214 | ||
48896466 GC |
215 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
216 | struct shrink_control *sc) | |
4a6c1297 | 217 | { |
48896466 GC |
218 | /* we can free zero page only if last reference remains */ |
219 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
220 | } | |
97ae1749 | 221 | |
48896466 GC |
222 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
223 | struct shrink_control *sc) | |
224 | { | |
97ae1749 | 225 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
226 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
227 | BUG_ON(zero_page == NULL); | |
228 | __free_page(zero_page); | |
48896466 | 229 | return HPAGE_PMD_NR; |
97ae1749 KS |
230 | } |
231 | ||
232 | return 0; | |
4a6c1297 KS |
233 | } |
234 | ||
97ae1749 | 235 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
236 | .count_objects = shrink_huge_zero_page_count, |
237 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
238 | .seeks = DEFAULT_SEEKS, |
239 | }; | |
240 | ||
71e3aac0 | 241 | #ifdef CONFIG_SYSFS |
ba76149f | 242 | |
71e3aac0 AA |
243 | static ssize_t double_flag_show(struct kobject *kobj, |
244 | struct kobj_attribute *attr, char *buf, | |
245 | enum transparent_hugepage_flag enabled, | |
246 | enum transparent_hugepage_flag req_madv) | |
247 | { | |
248 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
249 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
250 | return sprintf(buf, "[always] madvise never\n"); | |
251 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
252 | return sprintf(buf, "always [madvise] never\n"); | |
253 | else | |
254 | return sprintf(buf, "always madvise [never]\n"); | |
255 | } | |
256 | static ssize_t double_flag_store(struct kobject *kobj, | |
257 | struct kobj_attribute *attr, | |
258 | const char *buf, size_t count, | |
259 | enum transparent_hugepage_flag enabled, | |
260 | enum transparent_hugepage_flag req_madv) | |
261 | { | |
262 | if (!memcmp("always", buf, | |
263 | min(sizeof("always")-1, count))) { | |
264 | set_bit(enabled, &transparent_hugepage_flags); | |
265 | clear_bit(req_madv, &transparent_hugepage_flags); | |
266 | } else if (!memcmp("madvise", buf, | |
267 | min(sizeof("madvise")-1, count))) { | |
268 | clear_bit(enabled, &transparent_hugepage_flags); | |
269 | set_bit(req_madv, &transparent_hugepage_flags); | |
270 | } else if (!memcmp("never", buf, | |
271 | min(sizeof("never")-1, count))) { | |
272 | clear_bit(enabled, &transparent_hugepage_flags); | |
273 | clear_bit(req_madv, &transparent_hugepage_flags); | |
274 | } else | |
275 | return -EINVAL; | |
276 | ||
277 | return count; | |
278 | } | |
279 | ||
280 | static ssize_t enabled_show(struct kobject *kobj, | |
281 | struct kobj_attribute *attr, char *buf) | |
282 | { | |
283 | return double_flag_show(kobj, attr, buf, | |
284 | TRANSPARENT_HUGEPAGE_FLAG, | |
285 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
286 | } | |
287 | static ssize_t enabled_store(struct kobject *kobj, | |
288 | struct kobj_attribute *attr, | |
289 | const char *buf, size_t count) | |
290 | { | |
ba76149f AA |
291 | ssize_t ret; |
292 | ||
293 | ret = double_flag_store(kobj, attr, buf, count, | |
294 | TRANSPARENT_HUGEPAGE_FLAG, | |
295 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
296 | ||
297 | if (ret > 0) { | |
911891af XG |
298 | int err; |
299 | ||
300 | mutex_lock(&khugepaged_mutex); | |
301 | err = start_khugepaged(); | |
302 | mutex_unlock(&khugepaged_mutex); | |
303 | ||
ba76149f AA |
304 | if (err) |
305 | ret = err; | |
306 | } | |
307 | ||
308 | return ret; | |
71e3aac0 AA |
309 | } |
310 | static struct kobj_attribute enabled_attr = | |
311 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
312 | ||
313 | static ssize_t single_flag_show(struct kobject *kobj, | |
314 | struct kobj_attribute *attr, char *buf, | |
315 | enum transparent_hugepage_flag flag) | |
316 | { | |
e27e6151 BH |
317 | return sprintf(buf, "%d\n", |
318 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 319 | } |
e27e6151 | 320 | |
71e3aac0 AA |
321 | static ssize_t single_flag_store(struct kobject *kobj, |
322 | struct kobj_attribute *attr, | |
323 | const char *buf, size_t count, | |
324 | enum transparent_hugepage_flag flag) | |
325 | { | |
e27e6151 BH |
326 | unsigned long value; |
327 | int ret; | |
328 | ||
329 | ret = kstrtoul(buf, 10, &value); | |
330 | if (ret < 0) | |
331 | return ret; | |
332 | if (value > 1) | |
333 | return -EINVAL; | |
334 | ||
335 | if (value) | |
71e3aac0 | 336 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 337 | else |
71e3aac0 | 338 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
339 | |
340 | return count; | |
341 | } | |
342 | ||
343 | /* | |
344 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
345 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
346 | * memory just to allocate one more hugepage. | |
347 | */ | |
348 | static ssize_t defrag_show(struct kobject *kobj, | |
349 | struct kobj_attribute *attr, char *buf) | |
350 | { | |
351 | return double_flag_show(kobj, attr, buf, | |
352 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
353 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
354 | } | |
355 | static ssize_t defrag_store(struct kobject *kobj, | |
356 | struct kobj_attribute *attr, | |
357 | const char *buf, size_t count) | |
358 | { | |
359 | return double_flag_store(kobj, attr, buf, count, | |
360 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
361 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
362 | } | |
363 | static struct kobj_attribute defrag_attr = | |
364 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
365 | ||
79da5407 KS |
366 | static ssize_t use_zero_page_show(struct kobject *kobj, |
367 | struct kobj_attribute *attr, char *buf) | |
368 | { | |
369 | return single_flag_show(kobj, attr, buf, | |
370 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
371 | } | |
372 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
373 | struct kobj_attribute *attr, const char *buf, size_t count) | |
374 | { | |
375 | return single_flag_store(kobj, attr, buf, count, | |
376 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
377 | } | |
378 | static struct kobj_attribute use_zero_page_attr = | |
379 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
71e3aac0 AA |
380 | #ifdef CONFIG_DEBUG_VM |
381 | static ssize_t debug_cow_show(struct kobject *kobj, | |
382 | struct kobj_attribute *attr, char *buf) | |
383 | { | |
384 | return single_flag_show(kobj, attr, buf, | |
385 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
386 | } | |
387 | static ssize_t debug_cow_store(struct kobject *kobj, | |
388 | struct kobj_attribute *attr, | |
389 | const char *buf, size_t count) | |
390 | { | |
391 | return single_flag_store(kobj, attr, buf, count, | |
392 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
393 | } | |
394 | static struct kobj_attribute debug_cow_attr = | |
395 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
396 | #endif /* CONFIG_DEBUG_VM */ | |
397 | ||
398 | static struct attribute *hugepage_attr[] = { | |
399 | &enabled_attr.attr, | |
400 | &defrag_attr.attr, | |
79da5407 | 401 | &use_zero_page_attr.attr, |
71e3aac0 AA |
402 | #ifdef CONFIG_DEBUG_VM |
403 | &debug_cow_attr.attr, | |
404 | #endif | |
405 | NULL, | |
406 | }; | |
407 | ||
408 | static struct attribute_group hugepage_attr_group = { | |
409 | .attrs = hugepage_attr, | |
ba76149f AA |
410 | }; |
411 | ||
412 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
413 | struct kobj_attribute *attr, | |
414 | char *buf) | |
415 | { | |
416 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
417 | } | |
418 | ||
419 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
420 | struct kobj_attribute *attr, | |
421 | const char *buf, size_t count) | |
422 | { | |
423 | unsigned long msecs; | |
424 | int err; | |
425 | ||
3dbb95f7 | 426 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
427 | if (err || msecs > UINT_MAX) |
428 | return -EINVAL; | |
429 | ||
430 | khugepaged_scan_sleep_millisecs = msecs; | |
431 | wake_up_interruptible(&khugepaged_wait); | |
432 | ||
433 | return count; | |
434 | } | |
435 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
436 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
437 | scan_sleep_millisecs_store); | |
438 | ||
439 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
440 | struct kobj_attribute *attr, | |
441 | char *buf) | |
442 | { | |
443 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
444 | } | |
445 | ||
446 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
447 | struct kobj_attribute *attr, | |
448 | const char *buf, size_t count) | |
449 | { | |
450 | unsigned long msecs; | |
451 | int err; | |
452 | ||
3dbb95f7 | 453 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
454 | if (err || msecs > UINT_MAX) |
455 | return -EINVAL; | |
456 | ||
457 | khugepaged_alloc_sleep_millisecs = msecs; | |
458 | wake_up_interruptible(&khugepaged_wait); | |
459 | ||
460 | return count; | |
461 | } | |
462 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
463 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
464 | alloc_sleep_millisecs_store); | |
465 | ||
466 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
467 | struct kobj_attribute *attr, | |
468 | char *buf) | |
469 | { | |
470 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
471 | } | |
472 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
473 | struct kobj_attribute *attr, | |
474 | const char *buf, size_t count) | |
475 | { | |
476 | int err; | |
477 | unsigned long pages; | |
478 | ||
3dbb95f7 | 479 | err = kstrtoul(buf, 10, &pages); |
ba76149f AA |
480 | if (err || !pages || pages > UINT_MAX) |
481 | return -EINVAL; | |
482 | ||
483 | khugepaged_pages_to_scan = pages; | |
484 | ||
485 | return count; | |
486 | } | |
487 | static struct kobj_attribute pages_to_scan_attr = | |
488 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
489 | pages_to_scan_store); | |
490 | ||
491 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
492 | struct kobj_attribute *attr, | |
493 | char *buf) | |
494 | { | |
495 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
496 | } | |
497 | static struct kobj_attribute pages_collapsed_attr = | |
498 | __ATTR_RO(pages_collapsed); | |
499 | ||
500 | static ssize_t full_scans_show(struct kobject *kobj, | |
501 | struct kobj_attribute *attr, | |
502 | char *buf) | |
503 | { | |
504 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
505 | } | |
506 | static struct kobj_attribute full_scans_attr = | |
507 | __ATTR_RO(full_scans); | |
508 | ||
509 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
510 | struct kobj_attribute *attr, char *buf) | |
511 | { | |
512 | return single_flag_show(kobj, attr, buf, | |
513 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
514 | } | |
515 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
516 | struct kobj_attribute *attr, | |
517 | const char *buf, size_t count) | |
518 | { | |
519 | return single_flag_store(kobj, attr, buf, count, | |
520 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
521 | } | |
522 | static struct kobj_attribute khugepaged_defrag_attr = | |
523 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
524 | khugepaged_defrag_store); | |
525 | ||
526 | /* | |
527 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
528 | * any unmapped ptes in turn potentially increasing the memory | |
529 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
530 | * reduce the available free memory in the system as it | |
531 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
532 | * free memory in the system during the khugepaged scan. | |
533 | */ | |
534 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
535 | struct kobj_attribute *attr, | |
536 | char *buf) | |
537 | { | |
538 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
539 | } | |
540 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
541 | struct kobj_attribute *attr, | |
542 | const char *buf, size_t count) | |
543 | { | |
544 | int err; | |
545 | unsigned long max_ptes_none; | |
546 | ||
3dbb95f7 | 547 | err = kstrtoul(buf, 10, &max_ptes_none); |
ba76149f AA |
548 | if (err || max_ptes_none > HPAGE_PMD_NR-1) |
549 | return -EINVAL; | |
550 | ||
551 | khugepaged_max_ptes_none = max_ptes_none; | |
552 | ||
553 | return count; | |
554 | } | |
555 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
556 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
557 | khugepaged_max_ptes_none_store); | |
558 | ||
559 | static struct attribute *khugepaged_attr[] = { | |
560 | &khugepaged_defrag_attr.attr, | |
561 | &khugepaged_max_ptes_none_attr.attr, | |
562 | &pages_to_scan_attr.attr, | |
563 | &pages_collapsed_attr.attr, | |
564 | &full_scans_attr.attr, | |
565 | &scan_sleep_millisecs_attr.attr, | |
566 | &alloc_sleep_millisecs_attr.attr, | |
567 | NULL, | |
568 | }; | |
569 | ||
570 | static struct attribute_group khugepaged_attr_group = { | |
571 | .attrs = khugepaged_attr, | |
572 | .name = "khugepaged", | |
71e3aac0 | 573 | }; |
71e3aac0 | 574 | |
569e5590 | 575 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 576 | { |
71e3aac0 AA |
577 | int err; |
578 | ||
569e5590 SL |
579 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
580 | if (unlikely(!*hugepage_kobj)) { | |
2c79737a | 581 | printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n"); |
569e5590 | 582 | return -ENOMEM; |
ba76149f AA |
583 | } |
584 | ||
569e5590 | 585 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 586 | if (err) { |
2c79737a | 587 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 588 | goto delete_obj; |
ba76149f AA |
589 | } |
590 | ||
569e5590 | 591 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 592 | if (err) { |
2c79737a | 593 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 594 | goto remove_hp_group; |
ba76149f | 595 | } |
569e5590 SL |
596 | |
597 | return 0; | |
598 | ||
599 | remove_hp_group: | |
600 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
601 | delete_obj: | |
602 | kobject_put(*hugepage_kobj); | |
603 | return err; | |
604 | } | |
605 | ||
606 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
607 | { | |
608 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
609 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
610 | kobject_put(hugepage_kobj); | |
611 | } | |
612 | #else | |
613 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
614 | { | |
615 | return 0; | |
616 | } | |
617 | ||
618 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
619 | { | |
620 | } | |
621 | #endif /* CONFIG_SYSFS */ | |
622 | ||
623 | static int __init hugepage_init(void) | |
624 | { | |
625 | int err; | |
626 | struct kobject *hugepage_kobj; | |
627 | ||
628 | if (!has_transparent_hugepage()) { | |
629 | transparent_hugepage_flags = 0; | |
630 | return -EINVAL; | |
631 | } | |
632 | ||
633 | err = hugepage_init_sysfs(&hugepage_kobj); | |
634 | if (err) | |
635 | return err; | |
ba76149f AA |
636 | |
637 | err = khugepaged_slab_init(); | |
638 | if (err) | |
639 | goto out; | |
640 | ||
97ae1749 KS |
641 | register_shrinker(&huge_zero_page_shrinker); |
642 | ||
97562cd2 RR |
643 | /* |
644 | * By default disable transparent hugepages on smaller systems, | |
645 | * where the extra memory used could hurt more than TLB overhead | |
646 | * is likely to save. The admin can still enable it through /sys. | |
647 | */ | |
648 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
649 | transparent_hugepage_flags = 0; | |
650 | ||
ba76149f AA |
651 | start_khugepaged(); |
652 | ||
569e5590 | 653 | return 0; |
ba76149f | 654 | out: |
569e5590 | 655 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 656 | return err; |
71e3aac0 AA |
657 | } |
658 | module_init(hugepage_init) | |
659 | ||
660 | static int __init setup_transparent_hugepage(char *str) | |
661 | { | |
662 | int ret = 0; | |
663 | if (!str) | |
664 | goto out; | |
665 | if (!strcmp(str, "always")) { | |
666 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
667 | &transparent_hugepage_flags); | |
668 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
669 | &transparent_hugepage_flags); | |
670 | ret = 1; | |
671 | } else if (!strcmp(str, "madvise")) { | |
672 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
673 | &transparent_hugepage_flags); | |
674 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
675 | &transparent_hugepage_flags); | |
676 | ret = 1; | |
677 | } else if (!strcmp(str, "never")) { | |
678 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
679 | &transparent_hugepage_flags); | |
680 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
681 | &transparent_hugepage_flags); | |
682 | ret = 1; | |
683 | } | |
684 | out: | |
685 | if (!ret) | |
686 | printk(KERN_WARNING | |
687 | "transparent_hugepage= cannot parse, ignored\n"); | |
688 | return ret; | |
689 | } | |
690 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
691 | ||
b32967ff | 692 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
693 | { |
694 | if (likely(vma->vm_flags & VM_WRITE)) | |
695 | pmd = pmd_mkwrite(pmd); | |
696 | return pmd; | |
697 | } | |
698 | ||
3122359a | 699 | static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) |
b3092b3b BL |
700 | { |
701 | pmd_t entry; | |
3122359a | 702 | entry = mk_pmd(page, prot); |
b3092b3b BL |
703 | entry = pmd_mkhuge(entry); |
704 | return entry; | |
705 | } | |
706 | ||
71e3aac0 AA |
707 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
708 | struct vm_area_struct *vma, | |
709 | unsigned long haddr, pmd_t *pmd, | |
710 | struct page *page) | |
711 | { | |
71e3aac0 | 712 | pgtable_t pgtable; |
c4088ebd | 713 | spinlock_t *ptl; |
71e3aac0 | 714 | |
309381fe | 715 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
71e3aac0 | 716 | pgtable = pte_alloc_one(mm, haddr); |
edad9d2c | 717 | if (unlikely(!pgtable)) |
71e3aac0 | 718 | return VM_FAULT_OOM; |
71e3aac0 AA |
719 | |
720 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
52f37629 MK |
721 | /* |
722 | * The memory barrier inside __SetPageUptodate makes sure that | |
723 | * clear_huge_page writes become visible before the set_pmd_at() | |
724 | * write. | |
725 | */ | |
71e3aac0 AA |
726 | __SetPageUptodate(page); |
727 | ||
c4088ebd | 728 | ptl = pmd_lock(mm, pmd); |
71e3aac0 | 729 | if (unlikely(!pmd_none(*pmd))) { |
c4088ebd | 730 | spin_unlock(ptl); |
b9bbfbe3 | 731 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
732 | put_page(page); |
733 | pte_free(mm, pgtable); | |
734 | } else { | |
735 | pmd_t entry; | |
3122359a KS |
736 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
737 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
71e3aac0 | 738 | page_add_new_anon_rmap(page, vma, haddr); |
6b0b50b0 | 739 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
71e3aac0 | 740 | set_pmd_at(mm, haddr, pmd, entry); |
71e3aac0 | 741 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
e1f56c89 | 742 | atomic_long_inc(&mm->nr_ptes); |
c4088ebd | 743 | spin_unlock(ptl); |
71e3aac0 AA |
744 | } |
745 | ||
aa2e878e | 746 | return 0; |
71e3aac0 AA |
747 | } |
748 | ||
cc5d462f | 749 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 750 | { |
cc5d462f | 751 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
752 | } |
753 | ||
754 | static inline struct page *alloc_hugepage_vma(int defrag, | |
755 | struct vm_area_struct *vma, | |
cc5d462f AK |
756 | unsigned long haddr, int nd, |
757 | gfp_t extra_gfp) | |
0bbbc0b3 | 758 | { |
cc5d462f | 759 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 760 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
761 | } |
762 | ||
c4088ebd | 763 | /* Caller must hold page table lock. */ |
3ea41e62 | 764 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 765 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 766 | struct page *zero_page) |
fc9fe822 KS |
767 | { |
768 | pmd_t entry; | |
3ea41e62 KS |
769 | if (!pmd_none(*pmd)) |
770 | return false; | |
5918d10a | 771 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 KS |
772 | entry = pmd_wrprotect(entry); |
773 | entry = pmd_mkhuge(entry); | |
6b0b50b0 | 774 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 775 | set_pmd_at(mm, haddr, pmd, entry); |
e1f56c89 | 776 | atomic_long_inc(&mm->nr_ptes); |
3ea41e62 | 777 | return true; |
fc9fe822 KS |
778 | } |
779 | ||
71e3aac0 AA |
780 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
781 | unsigned long address, pmd_t *pmd, | |
782 | unsigned int flags) | |
783 | { | |
784 | struct page *page; | |
785 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
71e3aac0 | 786 | |
128ec037 | 787 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 788 | return VM_FAULT_FALLBACK; |
128ec037 KS |
789 | if (unlikely(anon_vma_prepare(vma))) |
790 | return VM_FAULT_OOM; | |
791 | if (unlikely(khugepaged_enter(vma))) | |
792 | return VM_FAULT_OOM; | |
793 | if (!(flags & FAULT_FLAG_WRITE) && | |
794 | transparent_hugepage_use_zero_page()) { | |
c4088ebd | 795 | spinlock_t *ptl; |
128ec037 KS |
796 | pgtable_t pgtable; |
797 | struct page *zero_page; | |
798 | bool set; | |
799 | pgtable = pte_alloc_one(mm, haddr); | |
800 | if (unlikely(!pgtable)) | |
ba76149f | 801 | return VM_FAULT_OOM; |
128ec037 KS |
802 | zero_page = get_huge_zero_page(); |
803 | if (unlikely(!zero_page)) { | |
804 | pte_free(mm, pgtable); | |
81ab4201 | 805 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 806 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 807 | } |
c4088ebd | 808 | ptl = pmd_lock(mm, pmd); |
128ec037 KS |
809 | set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, |
810 | zero_page); | |
c4088ebd | 811 | spin_unlock(ptl); |
128ec037 KS |
812 | if (!set) { |
813 | pte_free(mm, pgtable); | |
814 | put_huge_zero_page(); | |
edad9d2c | 815 | } |
edad9d2c | 816 | return 0; |
71e3aac0 | 817 | } |
128ec037 KS |
818 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
819 | vma, haddr, numa_node_id(), 0); | |
820 | if (unlikely(!page)) { | |
821 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 822 | return VM_FAULT_FALLBACK; |
128ec037 | 823 | } |
128ec037 KS |
824 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
825 | put_page(page); | |
17766dde | 826 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 827 | return VM_FAULT_FALLBACK; |
128ec037 KS |
828 | } |
829 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) { | |
830 | mem_cgroup_uncharge_page(page); | |
831 | put_page(page); | |
17766dde | 832 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 833 | return VM_FAULT_FALLBACK; |
128ec037 KS |
834 | } |
835 | ||
17766dde | 836 | count_vm_event(THP_FAULT_ALLOC); |
128ec037 | 837 | return 0; |
71e3aac0 AA |
838 | } |
839 | ||
840 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
841 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
842 | struct vm_area_struct *vma) | |
843 | { | |
c4088ebd | 844 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
845 | struct page *src_page; |
846 | pmd_t pmd; | |
847 | pgtable_t pgtable; | |
848 | int ret; | |
849 | ||
850 | ret = -ENOMEM; | |
851 | pgtable = pte_alloc_one(dst_mm, addr); | |
852 | if (unlikely(!pgtable)) | |
853 | goto out; | |
854 | ||
c4088ebd KS |
855 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
856 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
857 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
858 | |
859 | ret = -EAGAIN; | |
860 | pmd = *src_pmd; | |
861 | if (unlikely(!pmd_trans_huge(pmd))) { | |
862 | pte_free(dst_mm, pgtable); | |
863 | goto out_unlock; | |
864 | } | |
fc9fe822 | 865 | /* |
c4088ebd | 866 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
867 | * under splitting since we don't split the page itself, only pmd to |
868 | * a page table. | |
869 | */ | |
870 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 871 | struct page *zero_page; |
3ea41e62 | 872 | bool set; |
97ae1749 KS |
873 | /* |
874 | * get_huge_zero_page() will never allocate a new page here, | |
875 | * since we already have a zero page to copy. It just takes a | |
876 | * reference. | |
877 | */ | |
5918d10a | 878 | zero_page = get_huge_zero_page(); |
3ea41e62 | 879 | set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 880 | zero_page); |
3ea41e62 | 881 | BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ |
fc9fe822 KS |
882 | ret = 0; |
883 | goto out_unlock; | |
884 | } | |
de466bd6 | 885 | |
71e3aac0 AA |
886 | if (unlikely(pmd_trans_splitting(pmd))) { |
887 | /* split huge page running from under us */ | |
c4088ebd KS |
888 | spin_unlock(src_ptl); |
889 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
890 | pte_free(dst_mm, pgtable); |
891 | ||
892 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
893 | goto out; | |
894 | } | |
895 | src_page = pmd_page(pmd); | |
309381fe | 896 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); |
71e3aac0 AA |
897 | get_page(src_page); |
898 | page_dup_rmap(src_page); | |
899 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
900 | ||
901 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
902 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
6b0b50b0 | 903 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 904 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
e1f56c89 | 905 | atomic_long_inc(&dst_mm->nr_ptes); |
71e3aac0 AA |
906 | |
907 | ret = 0; | |
908 | out_unlock: | |
c4088ebd KS |
909 | spin_unlock(src_ptl); |
910 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
911 | out: |
912 | return ret; | |
913 | } | |
914 | ||
a1dd450b WD |
915 | void huge_pmd_set_accessed(struct mm_struct *mm, |
916 | struct vm_area_struct *vma, | |
917 | unsigned long address, | |
918 | pmd_t *pmd, pmd_t orig_pmd, | |
919 | int dirty) | |
920 | { | |
c4088ebd | 921 | spinlock_t *ptl; |
a1dd450b WD |
922 | pmd_t entry; |
923 | unsigned long haddr; | |
924 | ||
c4088ebd | 925 | ptl = pmd_lock(mm, pmd); |
a1dd450b WD |
926 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
927 | goto unlock; | |
928 | ||
929 | entry = pmd_mkyoung(orig_pmd); | |
930 | haddr = address & HPAGE_PMD_MASK; | |
931 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
932 | update_mmu_cache_pmd(vma, address, pmd); | |
933 | ||
934 | unlock: | |
c4088ebd | 935 | spin_unlock(ptl); |
a1dd450b WD |
936 | } |
937 | ||
93b4796d KS |
938 | static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, |
939 | struct vm_area_struct *vma, unsigned long address, | |
3ea41e62 | 940 | pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr) |
93b4796d | 941 | { |
c4088ebd | 942 | spinlock_t *ptl; |
93b4796d KS |
943 | pgtable_t pgtable; |
944 | pmd_t _pmd; | |
945 | struct page *page; | |
946 | int i, ret = 0; | |
947 | unsigned long mmun_start; /* For mmu_notifiers */ | |
948 | unsigned long mmun_end; /* For mmu_notifiers */ | |
949 | ||
950 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
951 | if (!page) { | |
952 | ret |= VM_FAULT_OOM; | |
953 | goto out; | |
954 | } | |
955 | ||
956 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { | |
957 | put_page(page); | |
958 | ret |= VM_FAULT_OOM; | |
959 | goto out; | |
960 | } | |
961 | ||
962 | clear_user_highpage(page, address); | |
963 | __SetPageUptodate(page); | |
964 | ||
965 | mmun_start = haddr; | |
966 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
967 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
968 | ||
c4088ebd | 969 | ptl = pmd_lock(mm, pmd); |
3ea41e62 KS |
970 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
971 | goto out_free_page; | |
972 | ||
93b4796d KS |
973 | pmdp_clear_flush(vma, haddr, pmd); |
974 | /* leave pmd empty until pte is filled */ | |
975 | ||
6b0b50b0 | 976 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
93b4796d KS |
977 | pmd_populate(mm, &_pmd, pgtable); |
978 | ||
979 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
980 | pte_t *pte, entry; | |
981 | if (haddr == (address & PAGE_MASK)) { | |
982 | entry = mk_pte(page, vma->vm_page_prot); | |
983 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
984 | page_add_new_anon_rmap(page, vma, haddr); | |
985 | } else { | |
986 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
987 | entry = pte_mkspecial(entry); | |
988 | } | |
989 | pte = pte_offset_map(&_pmd, haddr); | |
990 | VM_BUG_ON(!pte_none(*pte)); | |
991 | set_pte_at(mm, haddr, pte, entry); | |
992 | pte_unmap(pte); | |
993 | } | |
994 | smp_wmb(); /* make pte visible before pmd */ | |
995 | pmd_populate(mm, pmd, pgtable); | |
c4088ebd | 996 | spin_unlock(ptl); |
97ae1749 | 997 | put_huge_zero_page(); |
93b4796d KS |
998 | inc_mm_counter(mm, MM_ANONPAGES); |
999 | ||
1000 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1001 | ||
1002 | ret |= VM_FAULT_WRITE; | |
1003 | out: | |
1004 | return ret; | |
3ea41e62 | 1005 | out_free_page: |
c4088ebd | 1006 | spin_unlock(ptl); |
3ea41e62 KS |
1007 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1008 | mem_cgroup_uncharge_page(page); | |
1009 | put_page(page); | |
1010 | goto out; | |
93b4796d KS |
1011 | } |
1012 | ||
71e3aac0 AA |
1013 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
1014 | struct vm_area_struct *vma, | |
1015 | unsigned long address, | |
1016 | pmd_t *pmd, pmd_t orig_pmd, | |
1017 | struct page *page, | |
1018 | unsigned long haddr) | |
1019 | { | |
c4088ebd | 1020 | spinlock_t *ptl; |
71e3aac0 AA |
1021 | pgtable_t pgtable; |
1022 | pmd_t _pmd; | |
1023 | int ret = 0, i; | |
1024 | struct page **pages; | |
2ec74c3e SG |
1025 | unsigned long mmun_start; /* For mmu_notifiers */ |
1026 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1027 | |
1028 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1029 | GFP_KERNEL); | |
1030 | if (unlikely(!pages)) { | |
1031 | ret |= VM_FAULT_OOM; | |
1032 | goto out; | |
1033 | } | |
1034 | ||
1035 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
1036 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
1037 | __GFP_OTHER_NODE, | |
19ee151e | 1038 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
1039 | if (unlikely(!pages[i] || |
1040 | mem_cgroup_newpage_charge(pages[i], mm, | |
1041 | GFP_KERNEL))) { | |
1042 | if (pages[i]) | |
71e3aac0 | 1043 | put_page(pages[i]); |
b9bbfbe3 AA |
1044 | mem_cgroup_uncharge_start(); |
1045 | while (--i >= 0) { | |
1046 | mem_cgroup_uncharge_page(pages[i]); | |
1047 | put_page(pages[i]); | |
1048 | } | |
1049 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1050 | kfree(pages); |
1051 | ret |= VM_FAULT_OOM; | |
1052 | goto out; | |
1053 | } | |
1054 | } | |
1055 | ||
1056 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1057 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1058 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1059 | __SetPageUptodate(pages[i]); |
1060 | cond_resched(); | |
1061 | } | |
1062 | ||
2ec74c3e SG |
1063 | mmun_start = haddr; |
1064 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1065 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1066 | ||
c4088ebd | 1067 | ptl = pmd_lock(mm, pmd); |
71e3aac0 AA |
1068 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
1069 | goto out_free_pages; | |
309381fe | 1070 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1071 | |
2ec74c3e | 1072 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1073 | /* leave pmd empty until pte is filled */ |
1074 | ||
6b0b50b0 | 1075 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1076 | pmd_populate(mm, &_pmd, pgtable); |
1077 | ||
1078 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1079 | pte_t *pte, entry; | |
1080 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
1081 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1082 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
1083 | pte = pte_offset_map(&_pmd, haddr); | |
1084 | VM_BUG_ON(!pte_none(*pte)); | |
1085 | set_pte_at(mm, haddr, pte, entry); | |
1086 | pte_unmap(pte); | |
1087 | } | |
1088 | kfree(pages); | |
1089 | ||
71e3aac0 AA |
1090 | smp_wmb(); /* make pte visible before pmd */ |
1091 | pmd_populate(mm, pmd, pgtable); | |
1092 | page_remove_rmap(page); | |
c4088ebd | 1093 | spin_unlock(ptl); |
71e3aac0 | 1094 | |
2ec74c3e SG |
1095 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1096 | ||
71e3aac0 AA |
1097 | ret |= VM_FAULT_WRITE; |
1098 | put_page(page); | |
1099 | ||
1100 | out: | |
1101 | return ret; | |
1102 | ||
1103 | out_free_pages: | |
c4088ebd | 1104 | spin_unlock(ptl); |
2ec74c3e | 1105 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1106 | mem_cgroup_uncharge_start(); |
1107 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1108 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1109 | put_page(pages[i]); |
b9bbfbe3 AA |
1110 | } |
1111 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1112 | kfree(pages); |
1113 | goto out; | |
1114 | } | |
1115 | ||
1116 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1117 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1118 | { | |
c4088ebd | 1119 | spinlock_t *ptl; |
71e3aac0 | 1120 | int ret = 0; |
93b4796d | 1121 | struct page *page = NULL, *new_page; |
71e3aac0 | 1122 | unsigned long haddr; |
2ec74c3e SG |
1123 | unsigned long mmun_start; /* For mmu_notifiers */ |
1124 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 | 1125 | |
c4088ebd | 1126 | ptl = pmd_lockptr(mm, pmd); |
71e3aac0 | 1127 | VM_BUG_ON(!vma->anon_vma); |
93b4796d KS |
1128 | haddr = address & HPAGE_PMD_MASK; |
1129 | if (is_huge_zero_pmd(orig_pmd)) | |
1130 | goto alloc; | |
c4088ebd | 1131 | spin_lock(ptl); |
71e3aac0 AA |
1132 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
1133 | goto out_unlock; | |
1134 | ||
1135 | page = pmd_page(orig_pmd); | |
309381fe | 1136 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
71e3aac0 AA |
1137 | if (page_mapcount(page) == 1) { |
1138 | pmd_t entry; | |
1139 | entry = pmd_mkyoung(orig_pmd); | |
1140 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1141 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1142 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1143 | ret |= VM_FAULT_WRITE; |
1144 | goto out_unlock; | |
1145 | } | |
1146 | get_page(page); | |
c4088ebd | 1147 | spin_unlock(ptl); |
93b4796d | 1148 | alloc: |
71e3aac0 AA |
1149 | if (transparent_hugepage_enabled(vma) && |
1150 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1151 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1152 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1153 | else |
1154 | new_page = NULL; | |
1155 | ||
1156 | if (unlikely(!new_page)) { | |
eecc1e42 | 1157 | if (!page) { |
93b4796d | 1158 | ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, |
3ea41e62 | 1159 | address, pmd, orig_pmd, haddr); |
93b4796d KS |
1160 | } else { |
1161 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1162 | pmd, orig_pmd, page, haddr); | |
1163 | if (ret & VM_FAULT_OOM) | |
1164 | split_huge_page(page); | |
1165 | put_page(page); | |
1166 | } | |
17766dde | 1167 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1168 | goto out; |
1169 | } | |
1170 | ||
b9bbfbe3 AA |
1171 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1172 | put_page(new_page); | |
93b4796d KS |
1173 | if (page) { |
1174 | split_huge_page(page); | |
1175 | put_page(page); | |
1176 | } | |
17766dde | 1177 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1178 | ret |= VM_FAULT_OOM; |
1179 | goto out; | |
1180 | } | |
1181 | ||
17766dde DR |
1182 | count_vm_event(THP_FAULT_ALLOC); |
1183 | ||
eecc1e42 | 1184 | if (!page) |
93b4796d KS |
1185 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); |
1186 | else | |
1187 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1188 | __SetPageUptodate(new_page); |
1189 | ||
2ec74c3e SG |
1190 | mmun_start = haddr; |
1191 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1192 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1193 | ||
c4088ebd | 1194 | spin_lock(ptl); |
93b4796d KS |
1195 | if (page) |
1196 | put_page(page); | |
b9bbfbe3 | 1197 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
c4088ebd | 1198 | spin_unlock(ptl); |
b9bbfbe3 | 1199 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1200 | put_page(new_page); |
2ec74c3e | 1201 | goto out_mn; |
b9bbfbe3 | 1202 | } else { |
71e3aac0 | 1203 | pmd_t entry; |
3122359a KS |
1204 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1205 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
2ec74c3e | 1206 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1207 | page_add_new_anon_rmap(new_page, vma, haddr); |
1208 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1209 | update_mmu_cache_pmd(vma, address, pmd); |
eecc1e42 | 1210 | if (!page) { |
93b4796d | 1211 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 KS |
1212 | put_huge_zero_page(); |
1213 | } else { | |
309381fe | 1214 | VM_BUG_ON_PAGE(!PageHead(page), page); |
93b4796d KS |
1215 | page_remove_rmap(page); |
1216 | put_page(page); | |
1217 | } | |
71e3aac0 AA |
1218 | ret |= VM_FAULT_WRITE; |
1219 | } | |
c4088ebd | 1220 | spin_unlock(ptl); |
2ec74c3e SG |
1221 | out_mn: |
1222 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1223 | out: |
1224 | return ret; | |
2ec74c3e | 1225 | out_unlock: |
c4088ebd | 1226 | spin_unlock(ptl); |
2ec74c3e | 1227 | return ret; |
71e3aac0 AA |
1228 | } |
1229 | ||
b676b293 | 1230 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1231 | unsigned long addr, |
1232 | pmd_t *pmd, | |
1233 | unsigned int flags) | |
1234 | { | |
b676b293 | 1235 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1236 | struct page *page = NULL; |
1237 | ||
c4088ebd | 1238 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 AA |
1239 | |
1240 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1241 | goto out; | |
1242 | ||
85facf25 KS |
1243 | /* Avoid dumping huge zero page */ |
1244 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1245 | return ERR_PTR(-EFAULT); | |
1246 | ||
2b4847e7 MG |
1247 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
1248 | if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) | |
1249 | goto out; | |
1250 | ||
71e3aac0 | 1251 | page = pmd_page(*pmd); |
309381fe | 1252 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 AA |
1253 | if (flags & FOLL_TOUCH) { |
1254 | pmd_t _pmd; | |
1255 | /* | |
1256 | * We should set the dirty bit only for FOLL_WRITE but | |
1257 | * for now the dirty bit in the pmd is meaningless. | |
1258 | * And if the dirty bit will become meaningful and | |
1259 | * we'll only set it with FOLL_WRITE, an atomic | |
1260 | * set_bit will be required on the pmd to set the | |
1261 | * young bit, instead of the current set_pmd_at. | |
1262 | */ | |
1263 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
8663890a AK |
1264 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
1265 | pmd, _pmd, 1)) | |
1266 | update_mmu_cache_pmd(vma, addr, pmd); | |
71e3aac0 | 1267 | } |
b676b293 DR |
1268 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1269 | if (page->mapping && trylock_page(page)) { | |
1270 | lru_add_drain(); | |
1271 | if (page->mapping) | |
1272 | mlock_vma_page(page); | |
1273 | unlock_page(page); | |
1274 | } | |
1275 | } | |
71e3aac0 | 1276 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
309381fe | 1277 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
71e3aac0 | 1278 | if (flags & FOLL_GET) |
70b50f94 | 1279 | get_page_foll(page); |
71e3aac0 AA |
1280 | |
1281 | out: | |
1282 | return page; | |
1283 | } | |
1284 | ||
d10e63f2 | 1285 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1286 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1287 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1288 | { |
c4088ebd | 1289 | spinlock_t *ptl; |
b8916634 | 1290 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1291 | struct page *page; |
d10e63f2 | 1292 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
8191acbd | 1293 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1294 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1295 | bool page_locked; |
1296 | bool migrated = false; | |
6688cc05 | 1297 | int flags = 0; |
d10e63f2 | 1298 | |
c4088ebd | 1299 | ptl = pmd_lock(mm, pmdp); |
d10e63f2 MG |
1300 | if (unlikely(!pmd_same(pmd, *pmdp))) |
1301 | goto out_unlock; | |
1302 | ||
de466bd6 MG |
1303 | /* |
1304 | * If there are potential migrations, wait for completion and retry | |
1305 | * without disrupting NUMA hinting information. Do not relock and | |
1306 | * check_same as the page may no longer be mapped. | |
1307 | */ | |
1308 | if (unlikely(pmd_trans_migrating(*pmdp))) { | |
1309 | spin_unlock(ptl); | |
1310 | wait_migrate_huge_page(vma->anon_vma, pmdp); | |
1311 | goto out; | |
1312 | } | |
1313 | ||
d10e63f2 | 1314 | page = pmd_page(pmd); |
a1a46184 | 1315 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1316 | page_nid = page_to_nid(page); |
90572890 | 1317 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1318 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1319 | if (page_nid == this_nid) { |
03c5a6e1 | 1320 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1321 | flags |= TNF_FAULT_LOCAL; |
1322 | } | |
4daae3b4 | 1323 | |
6688cc05 PZ |
1324 | /* |
1325 | * Avoid grouping on DSO/COW pages in specific and RO pages | |
1326 | * in general, RO pages shouldn't hurt as much anyway since | |
1327 | * they can be in shared cache state. | |
1328 | */ | |
1329 | if (!pmd_write(pmd)) | |
1330 | flags |= TNF_NO_GROUP; | |
1331 | ||
ff9042b1 MG |
1332 | /* |
1333 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1334 | * page_table_lock if at all possible | |
1335 | */ | |
b8916634 MG |
1336 | page_locked = trylock_page(page); |
1337 | target_nid = mpol_misplaced(page, vma, haddr); | |
1338 | if (target_nid == -1) { | |
1339 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1340 | if (page_locked) |
b8916634 | 1341 | goto clear_pmdnuma; |
2b4847e7 | 1342 | } |
4daae3b4 | 1343 | |
de466bd6 | 1344 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1345 | if (!page_locked) { |
c4088ebd | 1346 | spin_unlock(ptl); |
b8916634 | 1347 | wait_on_page_locked(page); |
a54a407f | 1348 | page_nid = -1; |
b8916634 MG |
1349 | goto out; |
1350 | } | |
1351 | ||
2b4847e7 MG |
1352 | /* |
1353 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1354 | * to serialises splits | |
1355 | */ | |
b8916634 | 1356 | get_page(page); |
c4088ebd | 1357 | spin_unlock(ptl); |
b8916634 | 1358 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1359 | |
c69307d5 | 1360 | /* Confirm the PMD did not change while page_table_lock was released */ |
c4088ebd | 1361 | spin_lock(ptl); |
b32967ff MG |
1362 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1363 | unlock_page(page); | |
1364 | put_page(page); | |
a54a407f | 1365 | page_nid = -1; |
4daae3b4 | 1366 | goto out_unlock; |
b32967ff | 1367 | } |
ff9042b1 | 1368 | |
c3a489ca MG |
1369 | /* Bail if we fail to protect against THP splits for any reason */ |
1370 | if (unlikely(!anon_vma)) { | |
1371 | put_page(page); | |
1372 | page_nid = -1; | |
1373 | goto clear_pmdnuma; | |
1374 | } | |
1375 | ||
a54a407f MG |
1376 | /* |
1377 | * Migrate the THP to the requested node, returns with page unlocked | |
1378 | * and pmd_numa cleared. | |
1379 | */ | |
c4088ebd | 1380 | spin_unlock(ptl); |
b32967ff | 1381 | migrated = migrate_misplaced_transhuge_page(mm, vma, |
340ef390 | 1382 | pmdp, pmd, addr, page, target_nid); |
6688cc05 PZ |
1383 | if (migrated) { |
1384 | flags |= TNF_MIGRATED; | |
8191acbd | 1385 | page_nid = target_nid; |
6688cc05 | 1386 | } |
b32967ff | 1387 | |
8191acbd | 1388 | goto out; |
b32967ff | 1389 | clear_pmdnuma: |
a54a407f | 1390 | BUG_ON(!PageLocked(page)); |
d10e63f2 MG |
1391 | pmd = pmd_mknonnuma(pmd); |
1392 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1393 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1394 | update_mmu_cache_pmd(vma, addr, pmdp); | |
a54a407f | 1395 | unlock_page(page); |
d10e63f2 | 1396 | out_unlock: |
c4088ebd | 1397 | spin_unlock(ptl); |
b8916634 MG |
1398 | |
1399 | out: | |
1400 | if (anon_vma) | |
1401 | page_unlock_anon_vma_read(anon_vma); | |
1402 | ||
8191acbd | 1403 | if (page_nid != -1) |
6688cc05 | 1404 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags); |
8191acbd | 1405 | |
d10e63f2 MG |
1406 | return 0; |
1407 | } | |
1408 | ||
71e3aac0 | 1409 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1410 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1411 | { |
bf929152 | 1412 | spinlock_t *ptl; |
71e3aac0 AA |
1413 | int ret = 0; |
1414 | ||
bf929152 | 1415 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 NH |
1416 | struct page *page; |
1417 | pgtable_t pgtable; | |
f5c8ad47 | 1418 | pmd_t orig_pmd; |
a6bf2bb0 AK |
1419 | /* |
1420 | * For architectures like ppc64 we look at deposited pgtable | |
1421 | * when calling pmdp_get_and_clear. So do the | |
1422 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1423 | * operations. | |
1424 | */ | |
f5c8ad47 | 1425 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1426 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
a6bf2bb0 | 1427 | pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); |
479f0abb | 1428 | if (is_huge_zero_pmd(orig_pmd)) { |
e1f56c89 | 1429 | atomic_long_dec(&tlb->mm->nr_ptes); |
bf929152 | 1430 | spin_unlock(ptl); |
97ae1749 | 1431 | put_huge_zero_page(); |
479f0abb KS |
1432 | } else { |
1433 | page = pmd_page(orig_pmd); | |
1434 | page_remove_rmap(page); | |
309381fe | 1435 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
479f0abb | 1436 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
309381fe | 1437 | VM_BUG_ON_PAGE(!PageHead(page), page); |
e1f56c89 | 1438 | atomic_long_dec(&tlb->mm->nr_ptes); |
bf929152 | 1439 | spin_unlock(ptl); |
479f0abb KS |
1440 | tlb_remove_page(tlb, page); |
1441 | } | |
025c5b24 NH |
1442 | pte_free(tlb->mm, pgtable); |
1443 | ret = 1; | |
1444 | } | |
71e3aac0 AA |
1445 | return ret; |
1446 | } | |
1447 | ||
0ca1634d JW |
1448 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1449 | unsigned long addr, unsigned long end, | |
1450 | unsigned char *vec) | |
1451 | { | |
bf929152 | 1452 | spinlock_t *ptl; |
0ca1634d JW |
1453 | int ret = 0; |
1454 | ||
bf929152 | 1455 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 NH |
1456 | /* |
1457 | * All logical pages in the range are present | |
1458 | * if backed by a huge page. | |
1459 | */ | |
bf929152 | 1460 | spin_unlock(ptl); |
025c5b24 NH |
1461 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1462 | ret = 1; | |
1463 | } | |
0ca1634d JW |
1464 | |
1465 | return ret; | |
1466 | } | |
1467 | ||
37a1c49a AA |
1468 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1469 | unsigned long old_addr, | |
1470 | unsigned long new_addr, unsigned long old_end, | |
1471 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1472 | { | |
bf929152 | 1473 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a AA |
1474 | int ret = 0; |
1475 | pmd_t pmd; | |
1476 | ||
1477 | struct mm_struct *mm = vma->vm_mm; | |
1478 | ||
1479 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1480 | (new_addr & ~HPAGE_PMD_MASK) || | |
1481 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1482 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1483 | goto out; | |
1484 | ||
1485 | /* | |
1486 | * The destination pmd shouldn't be established, free_pgtables() | |
1487 | * should have release it. | |
1488 | */ | |
1489 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1490 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1491 | goto out; | |
1492 | } | |
1493 | ||
bf929152 KS |
1494 | /* |
1495 | * We don't have to worry about the ordering of src and dst | |
1496 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1497 | */ | |
1498 | ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl); | |
025c5b24 | 1499 | if (ret == 1) { |
bf929152 KS |
1500 | new_ptl = pmd_lockptr(mm, new_pmd); |
1501 | if (new_ptl != old_ptl) | |
1502 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
025c5b24 NH |
1503 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); |
1504 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
0f8975ec | 1505 | set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); |
3592806c KS |
1506 | if (new_ptl != old_ptl) { |
1507 | pgtable_t pgtable; | |
1508 | ||
1509 | /* | |
1510 | * Move preallocated PTE page table if new_pmd is on | |
1511 | * different PMD page table. | |
1512 | */ | |
1513 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); | |
1514 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
1515 | ||
bf929152 | 1516 | spin_unlock(new_ptl); |
3592806c | 1517 | } |
bf929152 | 1518 | spin_unlock(old_ptl); |
37a1c49a AA |
1519 | } |
1520 | out: | |
1521 | return ret; | |
1522 | } | |
1523 | ||
f123d74a MG |
1524 | /* |
1525 | * Returns | |
1526 | * - 0 if PMD could not be locked | |
1527 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1528 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1529 | */ | |
cd7548ab | 1530 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1531 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1532 | { |
1533 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1534 | spinlock_t *ptl; |
cd7548ab JW |
1535 | int ret = 0; |
1536 | ||
bf929152 | 1537 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 | 1538 | pmd_t entry; |
f123d74a | 1539 | ret = 1; |
a4f1de17 | 1540 | if (!prot_numa) { |
f123d74a | 1541 | entry = pmdp_get_and_clear(mm, addr, pmd); |
1667918b MG |
1542 | if (pmd_numa(entry)) |
1543 | entry = pmd_mknonnuma(entry); | |
4b10e7d5 | 1544 | entry = pmd_modify(entry, newprot); |
f123d74a | 1545 | ret = HPAGE_PMD_NR; |
a4f1de17 HD |
1546 | BUG_ON(pmd_write(entry)); |
1547 | } else { | |
4b10e7d5 MG |
1548 | struct page *page = pmd_page(*pmd); |
1549 | ||
a1a46184 | 1550 | /* |
1bc115d8 MG |
1551 | * Do not trap faults against the zero page. The |
1552 | * read-only data is likely to be read-cached on the | |
1553 | * local CPU cache and it is less useful to know about | |
1554 | * local vs remote hits on the zero page. | |
a1a46184 | 1555 | */ |
1bc115d8 | 1556 | if (!is_huge_zero_page(page) && |
4b10e7d5 | 1557 | !pmd_numa(*pmd)) { |
5a6dac3e | 1558 | entry = *pmd; |
4b10e7d5 | 1559 | entry = pmd_mknuma(entry); |
f123d74a | 1560 | ret = HPAGE_PMD_NR; |
4b10e7d5 MG |
1561 | } |
1562 | } | |
f123d74a MG |
1563 | |
1564 | /* Set PMD if cleared earlier */ | |
1565 | if (ret == HPAGE_PMD_NR) | |
1566 | set_pmd_at(mm, addr, pmd, entry); | |
1567 | ||
bf929152 | 1568 | spin_unlock(ptl); |
025c5b24 NH |
1569 | } |
1570 | ||
1571 | return ret; | |
1572 | } | |
1573 | ||
1574 | /* | |
1575 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1576 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1577 | * | |
1578 | * Note that if it returns 1, this routine returns without unlocking page | |
1579 | * table locks. So callers must unlock them. | |
1580 | */ | |
bf929152 KS |
1581 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, |
1582 | spinlock_t **ptl) | |
025c5b24 | 1583 | { |
bf929152 | 1584 | *ptl = pmd_lock(vma->vm_mm, pmd); |
cd7548ab JW |
1585 | if (likely(pmd_trans_huge(*pmd))) { |
1586 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
bf929152 | 1587 | spin_unlock(*ptl); |
cd7548ab | 1588 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1589 | return -1; |
cd7548ab | 1590 | } else { |
025c5b24 NH |
1591 | /* Thp mapped by 'pmd' is stable, so we can |
1592 | * handle it as it is. */ | |
1593 | return 1; | |
cd7548ab | 1594 | } |
025c5b24 | 1595 | } |
bf929152 | 1596 | spin_unlock(*ptl); |
025c5b24 | 1597 | return 0; |
cd7548ab JW |
1598 | } |
1599 | ||
117b0791 KS |
1600 | /* |
1601 | * This function returns whether a given @page is mapped onto the @address | |
1602 | * in the virtual space of @mm. | |
1603 | * | |
1604 | * When it's true, this function returns *pmd with holding the page table lock | |
1605 | * and passing it back to the caller via @ptl. | |
1606 | * If it's false, returns NULL without holding the page table lock. | |
1607 | */ | |
71e3aac0 AA |
1608 | pmd_t *page_check_address_pmd(struct page *page, |
1609 | struct mm_struct *mm, | |
1610 | unsigned long address, | |
117b0791 KS |
1611 | enum page_check_address_pmd_flag flag, |
1612 | spinlock_t **ptl) | |
71e3aac0 | 1613 | { |
117b0791 | 1614 | pmd_t *pmd; |
71e3aac0 AA |
1615 | |
1616 | if (address & ~HPAGE_PMD_MASK) | |
117b0791 | 1617 | return NULL; |
71e3aac0 | 1618 | |
6219049a BL |
1619 | pmd = mm_find_pmd(mm, address); |
1620 | if (!pmd) | |
117b0791 KS |
1621 | return NULL; |
1622 | *ptl = pmd_lock(mm, pmd); | |
71e3aac0 | 1623 | if (pmd_none(*pmd)) |
117b0791 | 1624 | goto unlock; |
71e3aac0 | 1625 | if (pmd_page(*pmd) != page) |
117b0791 | 1626 | goto unlock; |
94fcc585 AA |
1627 | /* |
1628 | * split_vma() may create temporary aliased mappings. There is | |
1629 | * no risk as long as all huge pmd are found and have their | |
1630 | * splitting bit set before __split_huge_page_refcount | |
1631 | * runs. Finding the same huge pmd more than once during the | |
1632 | * same rmap walk is not a problem. | |
1633 | */ | |
1634 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1635 | pmd_trans_splitting(*pmd)) | |
117b0791 | 1636 | goto unlock; |
71e3aac0 AA |
1637 | if (pmd_trans_huge(*pmd)) { |
1638 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1639 | !pmd_trans_splitting(*pmd)); | |
117b0791 | 1640 | return pmd; |
71e3aac0 | 1641 | } |
117b0791 KS |
1642 | unlock: |
1643 | spin_unlock(*ptl); | |
1644 | return NULL; | |
71e3aac0 AA |
1645 | } |
1646 | ||
1647 | static int __split_huge_page_splitting(struct page *page, | |
1648 | struct vm_area_struct *vma, | |
1649 | unsigned long address) | |
1650 | { | |
1651 | struct mm_struct *mm = vma->vm_mm; | |
117b0791 | 1652 | spinlock_t *ptl; |
71e3aac0 AA |
1653 | pmd_t *pmd; |
1654 | int ret = 0; | |
2ec74c3e SG |
1655 | /* For mmu_notifiers */ |
1656 | const unsigned long mmun_start = address; | |
1657 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1658 | |
2ec74c3e | 1659 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 | 1660 | pmd = page_check_address_pmd(page, mm, address, |
117b0791 | 1661 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl); |
71e3aac0 AA |
1662 | if (pmd) { |
1663 | /* | |
1664 | * We can't temporarily set the pmd to null in order | |
1665 | * to split it, the pmd must remain marked huge at all | |
1666 | * times or the VM won't take the pmd_trans_huge paths | |
5a505085 | 1667 | * and it won't wait on the anon_vma->root->rwsem to |
71e3aac0 AA |
1668 | * serialize against split_huge_page*. |
1669 | */ | |
2ec74c3e | 1670 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 | 1671 | ret = 1; |
117b0791 | 1672 | spin_unlock(ptl); |
71e3aac0 | 1673 | } |
2ec74c3e | 1674 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1675 | |
1676 | return ret; | |
1677 | } | |
1678 | ||
5bc7b8ac SL |
1679 | static void __split_huge_page_refcount(struct page *page, |
1680 | struct list_head *list) | |
71e3aac0 AA |
1681 | { |
1682 | int i; | |
71e3aac0 | 1683 | struct zone *zone = page_zone(page); |
fa9add64 | 1684 | struct lruvec *lruvec; |
70b50f94 | 1685 | int tail_count = 0; |
71e3aac0 AA |
1686 | |
1687 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1688 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1689 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1690 | ||
71e3aac0 | 1691 | compound_lock(page); |
e94c8a9c KH |
1692 | /* complete memcg works before add pages to LRU */ |
1693 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1694 | |
45676885 | 1695 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1696 | struct page *page_tail = page + i; |
1697 | ||
70b50f94 AA |
1698 | /* tail_page->_mapcount cannot change */ |
1699 | BUG_ON(page_mapcount(page_tail) < 0); | |
1700 | tail_count += page_mapcount(page_tail); | |
1701 | /* check for overflow */ | |
1702 | BUG_ON(tail_count < 0); | |
1703 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1704 | /* | |
1705 | * tail_page->_count is zero and not changing from | |
1706 | * under us. But get_page_unless_zero() may be running | |
1707 | * from under us on the tail_page. If we used | |
1708 | * atomic_set() below instead of atomic_add(), we | |
1709 | * would then run atomic_set() concurrently with | |
1710 | * get_page_unless_zero(), and atomic_set() is | |
1711 | * implemented in C not using locked ops. spin_unlock | |
1712 | * on x86 sometime uses locked ops because of PPro | |
1713 | * errata 66, 92, so unless somebody can guarantee | |
1714 | * atomic_set() here would be safe on all archs (and | |
1715 | * not only on x86), it's safer to use atomic_add(). | |
1716 | */ | |
1717 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1718 | &page_tail->_count); | |
71e3aac0 AA |
1719 | |
1720 | /* after clearing PageTail the gup refcount can be released */ | |
1721 | smp_mb(); | |
1722 | ||
a6d30ddd JD |
1723 | /* |
1724 | * retain hwpoison flag of the poisoned tail page: | |
1725 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1726 | * by the memory-failure. | |
1727 | */ | |
1728 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1729 | page_tail->flags |= (page->flags & |
1730 | ((1L << PG_referenced) | | |
1731 | (1L << PG_swapbacked) | | |
1732 | (1L << PG_mlocked) | | |
e180cf80 KS |
1733 | (1L << PG_uptodate) | |
1734 | (1L << PG_active) | | |
1735 | (1L << PG_unevictable))); | |
71e3aac0 AA |
1736 | page_tail->flags |= (1L << PG_dirty); |
1737 | ||
70b50f94 | 1738 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1739 | smp_wmb(); |
1740 | ||
1741 | /* | |
1742 | * __split_huge_page_splitting() already set the | |
1743 | * splitting bit in all pmd that could map this | |
1744 | * hugepage, that will ensure no CPU can alter the | |
1745 | * mapcount on the head page. The mapcount is only | |
1746 | * accounted in the head page and it has to be | |
1747 | * transferred to all tail pages in the below code. So | |
1748 | * for this code to be safe, the split the mapcount | |
1749 | * can't change. But that doesn't mean userland can't | |
1750 | * keep changing and reading the page contents while | |
1751 | * we transfer the mapcount, so the pmd splitting | |
1752 | * status is achieved setting a reserved bit in the | |
1753 | * pmd, not by clearing the present bit. | |
1754 | */ | |
71e3aac0 AA |
1755 | page_tail->_mapcount = page->_mapcount; |
1756 | ||
1757 | BUG_ON(page_tail->mapping); | |
1758 | page_tail->mapping = page->mapping; | |
1759 | ||
45676885 | 1760 | page_tail->index = page->index + i; |
90572890 | 1761 | page_cpupid_xchg_last(page_tail, page_cpupid_last(page)); |
71e3aac0 AA |
1762 | |
1763 | BUG_ON(!PageAnon(page_tail)); | |
1764 | BUG_ON(!PageUptodate(page_tail)); | |
1765 | BUG_ON(!PageDirty(page_tail)); | |
1766 | BUG_ON(!PageSwapBacked(page_tail)); | |
1767 | ||
5bc7b8ac | 1768 | lru_add_page_tail(page, page_tail, lruvec, list); |
71e3aac0 | 1769 | } |
70b50f94 AA |
1770 | atomic_sub(tail_count, &page->_count); |
1771 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1772 | |
fa9add64 | 1773 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 | 1774 | |
71e3aac0 AA |
1775 | ClearPageCompound(page); |
1776 | compound_unlock(page); | |
1777 | spin_unlock_irq(&zone->lru_lock); | |
1778 | ||
1779 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1780 | struct page *page_tail = page + i; | |
1781 | BUG_ON(page_count(page_tail) <= 0); | |
1782 | /* | |
1783 | * Tail pages may be freed if there wasn't any mapping | |
1784 | * like if add_to_swap() is running on a lru page that | |
1785 | * had its mapping zapped. And freeing these pages | |
1786 | * requires taking the lru_lock so we do the put_page | |
1787 | * of the tail pages after the split is complete. | |
1788 | */ | |
1789 | put_page(page_tail); | |
1790 | } | |
1791 | ||
1792 | /* | |
1793 | * Only the head page (now become a regular page) is required | |
1794 | * to be pinned by the caller. | |
1795 | */ | |
1796 | BUG_ON(page_count(page) <= 0); | |
1797 | } | |
1798 | ||
1799 | static int __split_huge_page_map(struct page *page, | |
1800 | struct vm_area_struct *vma, | |
1801 | unsigned long address) | |
1802 | { | |
1803 | struct mm_struct *mm = vma->vm_mm; | |
117b0791 | 1804 | spinlock_t *ptl; |
71e3aac0 AA |
1805 | pmd_t *pmd, _pmd; |
1806 | int ret = 0, i; | |
1807 | pgtable_t pgtable; | |
1808 | unsigned long haddr; | |
1809 | ||
71e3aac0 | 1810 | pmd = page_check_address_pmd(page, mm, address, |
117b0791 | 1811 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl); |
71e3aac0 | 1812 | if (pmd) { |
6b0b50b0 | 1813 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1814 | pmd_populate(mm, &_pmd, pgtable); |
1815 | ||
e3ebcf64 GS |
1816 | haddr = address; |
1817 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1818 | pte_t *pte, entry; |
1819 | BUG_ON(PageCompound(page+i)); | |
1820 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1821 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1822 | if (!pmd_write(*pmd)) | |
1823 | entry = pte_wrprotect(entry); | |
1824 | else | |
1825 | BUG_ON(page_mapcount(page) != 1); | |
1826 | if (!pmd_young(*pmd)) | |
1827 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1828 | if (pmd_numa(*pmd)) |
1829 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1830 | pte = pte_offset_map(&_pmd, haddr); |
1831 | BUG_ON(!pte_none(*pte)); | |
1832 | set_pte_at(mm, haddr, pte, entry); | |
1833 | pte_unmap(pte); | |
1834 | } | |
1835 | ||
71e3aac0 AA |
1836 | smp_wmb(); /* make pte visible before pmd */ |
1837 | /* | |
1838 | * Up to this point the pmd is present and huge and | |
1839 | * userland has the whole access to the hugepage | |
1840 | * during the split (which happens in place). If we | |
1841 | * overwrite the pmd with the not-huge version | |
1842 | * pointing to the pte here (which of course we could | |
1843 | * if all CPUs were bug free), userland could trigger | |
1844 | * a small page size TLB miss on the small sized TLB | |
1845 | * while the hugepage TLB entry is still established | |
1846 | * in the huge TLB. Some CPU doesn't like that. See | |
1847 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1848 | * Erratum 383 on page 93. Intel should be safe but is | |
1849 | * also warns that it's only safe if the permission | |
1850 | * and cache attributes of the two entries loaded in | |
1851 | * the two TLB is identical (which should be the case | |
1852 | * here). But it is generally safer to never allow | |
1853 | * small and huge TLB entries for the same virtual | |
1854 | * address to be loaded simultaneously. So instead of | |
1855 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1856 | * mark the current pmd notpresent (atomically because | |
1857 | * here the pmd_trans_huge and pmd_trans_splitting | |
1858 | * must remain set at all times on the pmd until the | |
1859 | * split is complete for this pmd), then we flush the | |
1860 | * SMP TLB and finally we write the non-huge version | |
1861 | * of the pmd entry with pmd_populate. | |
1862 | */ | |
46dcde73 | 1863 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1864 | pmd_populate(mm, pmd, pgtable); |
1865 | ret = 1; | |
117b0791 | 1866 | spin_unlock(ptl); |
71e3aac0 | 1867 | } |
71e3aac0 AA |
1868 | |
1869 | return ret; | |
1870 | } | |
1871 | ||
5a505085 | 1872 | /* must be called with anon_vma->root->rwsem held */ |
71e3aac0 | 1873 | static void __split_huge_page(struct page *page, |
5bc7b8ac SL |
1874 | struct anon_vma *anon_vma, |
1875 | struct list_head *list) | |
71e3aac0 AA |
1876 | { |
1877 | int mapcount, mapcount2; | |
bf181b9f | 1878 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1879 | struct anon_vma_chain *avc; |
1880 | ||
1881 | BUG_ON(!PageHead(page)); | |
1882 | BUG_ON(PageTail(page)); | |
1883 | ||
1884 | mapcount = 0; | |
bf181b9f | 1885 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1886 | struct vm_area_struct *vma = avc->vma; |
1887 | unsigned long addr = vma_address(page, vma); | |
1888 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1889 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1890 | } | |
05759d38 AA |
1891 | /* |
1892 | * It is critical that new vmas are added to the tail of the | |
1893 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1894 | * and establishes a child pmd before | |
1895 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1896 | * we fail to prevent copy_huge_pmd() from running until the | |
1897 | * whole __split_huge_page() is complete), we will still see | |
1898 | * the newly established pmd of the child later during the | |
1899 | * walk, to be able to set it as pmd_trans_splitting too. | |
1900 | */ | |
1901 | if (mapcount != page_mapcount(page)) | |
1902 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1903 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1904 | BUG_ON(mapcount != page_mapcount(page)); |
1905 | ||
5bc7b8ac | 1906 | __split_huge_page_refcount(page, list); |
71e3aac0 AA |
1907 | |
1908 | mapcount2 = 0; | |
bf181b9f | 1909 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1910 | struct vm_area_struct *vma = avc->vma; |
1911 | unsigned long addr = vma_address(page, vma); | |
1912 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1913 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1914 | } | |
05759d38 AA |
1915 | if (mapcount != mapcount2) |
1916 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1917 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1918 | BUG_ON(mapcount != mapcount2); |
1919 | } | |
1920 | ||
5bc7b8ac SL |
1921 | /* |
1922 | * Split a hugepage into normal pages. This doesn't change the position of head | |
1923 | * page. If @list is null, tail pages will be added to LRU list, otherwise, to | |
1924 | * @list. Both head page and tail pages will inherit mapping, flags, and so on | |
1925 | * from the hugepage. | |
1926 | * Return 0 if the hugepage is split successfully otherwise return 1. | |
1927 | */ | |
1928 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
71e3aac0 AA |
1929 | { |
1930 | struct anon_vma *anon_vma; | |
1931 | int ret = 1; | |
1932 | ||
5918d10a | 1933 | BUG_ON(is_huge_zero_page(page)); |
71e3aac0 | 1934 | BUG_ON(!PageAnon(page)); |
062f1af2 MG |
1935 | |
1936 | /* | |
1937 | * The caller does not necessarily hold an mmap_sem that would prevent | |
1938 | * the anon_vma disappearing so we first we take a reference to it | |
1939 | * and then lock the anon_vma for write. This is similar to | |
1940 | * page_lock_anon_vma_read except the write lock is taken to serialise | |
1941 | * against parallel split or collapse operations. | |
1942 | */ | |
1943 | anon_vma = page_get_anon_vma(page); | |
71e3aac0 AA |
1944 | if (!anon_vma) |
1945 | goto out; | |
062f1af2 MG |
1946 | anon_vma_lock_write(anon_vma); |
1947 | ||
71e3aac0 AA |
1948 | ret = 0; |
1949 | if (!PageCompound(page)) | |
1950 | goto out_unlock; | |
1951 | ||
1952 | BUG_ON(!PageSwapBacked(page)); | |
5bc7b8ac | 1953 | __split_huge_page(page, anon_vma, list); |
81ab4201 | 1954 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1955 | |
1956 | BUG_ON(PageCompound(page)); | |
1957 | out_unlock: | |
08b52706 | 1958 | anon_vma_unlock_write(anon_vma); |
062f1af2 | 1959 | put_anon_vma(anon_vma); |
71e3aac0 AA |
1960 | out: |
1961 | return ret; | |
1962 | } | |
1963 | ||
4b6e1e37 | 1964 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1965 | |
60ab3244 AA |
1966 | int hugepage_madvise(struct vm_area_struct *vma, |
1967 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1968 | { |
8e72033f GS |
1969 | struct mm_struct *mm = vma->vm_mm; |
1970 | ||
a664b2d8 AA |
1971 | switch (advice) { |
1972 | case MADV_HUGEPAGE: | |
1973 | /* | |
1974 | * Be somewhat over-protective like KSM for now! | |
1975 | */ | |
78f11a25 | 1976 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1977 | return -EINVAL; |
8e72033f GS |
1978 | if (mm->def_flags & VM_NOHUGEPAGE) |
1979 | return -EINVAL; | |
a664b2d8 AA |
1980 | *vm_flags &= ~VM_NOHUGEPAGE; |
1981 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1982 | /* |
1983 | * If the vma become good for khugepaged to scan, | |
1984 | * register it here without waiting a page fault that | |
1985 | * may not happen any time soon. | |
1986 | */ | |
1987 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1988 | return -ENOMEM; | |
a664b2d8 AA |
1989 | break; |
1990 | case MADV_NOHUGEPAGE: | |
1991 | /* | |
1992 | * Be somewhat over-protective like KSM for now! | |
1993 | */ | |
78f11a25 | 1994 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1995 | return -EINVAL; |
1996 | *vm_flags &= ~VM_HUGEPAGE; | |
1997 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1998 | /* |
1999 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
2000 | * this vma even if we leave the mm registered in khugepaged if | |
2001 | * it got registered before VM_NOHUGEPAGE was set. | |
2002 | */ | |
a664b2d8 AA |
2003 | break; |
2004 | } | |
0af4e98b AA |
2005 | |
2006 | return 0; | |
2007 | } | |
2008 | ||
ba76149f AA |
2009 | static int __init khugepaged_slab_init(void) |
2010 | { | |
2011 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
2012 | sizeof(struct mm_slot), | |
2013 | __alignof__(struct mm_slot), 0, NULL); | |
2014 | if (!mm_slot_cache) | |
2015 | return -ENOMEM; | |
2016 | ||
2017 | return 0; | |
2018 | } | |
2019 | ||
ba76149f AA |
2020 | static inline struct mm_slot *alloc_mm_slot(void) |
2021 | { | |
2022 | if (!mm_slot_cache) /* initialization failed */ | |
2023 | return NULL; | |
2024 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
2025 | } | |
2026 | ||
2027 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
2028 | { | |
2029 | kmem_cache_free(mm_slot_cache, mm_slot); | |
2030 | } | |
2031 | ||
ba76149f AA |
2032 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) |
2033 | { | |
2034 | struct mm_slot *mm_slot; | |
ba76149f | 2035 | |
b67bfe0d | 2036 | hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) |
ba76149f AA |
2037 | if (mm == mm_slot->mm) |
2038 | return mm_slot; | |
43b5fbbd | 2039 | |
ba76149f AA |
2040 | return NULL; |
2041 | } | |
2042 | ||
2043 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
2044 | struct mm_slot *mm_slot) | |
2045 | { | |
ba76149f | 2046 | mm_slot->mm = mm; |
43b5fbbd | 2047 | hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); |
ba76149f AA |
2048 | } |
2049 | ||
2050 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
2051 | { | |
2052 | return atomic_read(&mm->mm_users) == 0; | |
2053 | } | |
2054 | ||
2055 | int __khugepaged_enter(struct mm_struct *mm) | |
2056 | { | |
2057 | struct mm_slot *mm_slot; | |
2058 | int wakeup; | |
2059 | ||
2060 | mm_slot = alloc_mm_slot(); | |
2061 | if (!mm_slot) | |
2062 | return -ENOMEM; | |
2063 | ||
2064 | /* __khugepaged_exit() must not run from under us */ | |
2065 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
2066 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
2067 | free_mm_slot(mm_slot); | |
2068 | return 0; | |
2069 | } | |
2070 | ||
2071 | spin_lock(&khugepaged_mm_lock); | |
2072 | insert_to_mm_slots_hash(mm, mm_slot); | |
2073 | /* | |
2074 | * Insert just behind the scanning cursor, to let the area settle | |
2075 | * down a little. | |
2076 | */ | |
2077 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
2078 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
2079 | spin_unlock(&khugepaged_mm_lock); | |
2080 | ||
2081 | atomic_inc(&mm->mm_count); | |
2082 | if (wakeup) | |
2083 | wake_up_interruptible(&khugepaged_wait); | |
2084 | ||
2085 | return 0; | |
2086 | } | |
2087 | ||
2088 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
2089 | { | |
2090 | unsigned long hstart, hend; | |
2091 | if (!vma->anon_vma) | |
2092 | /* | |
2093 | * Not yet faulted in so we will register later in the | |
2094 | * page fault if needed. | |
2095 | */ | |
2096 | return 0; | |
78f11a25 | 2097 | if (vma->vm_ops) |
ba76149f AA |
2098 | /* khugepaged not yet working on file or special mappings */ |
2099 | return 0; | |
b3b9c293 | 2100 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2101 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2102 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2103 | if (hstart < hend) | |
2104 | return khugepaged_enter(vma); | |
2105 | return 0; | |
2106 | } | |
2107 | ||
2108 | void __khugepaged_exit(struct mm_struct *mm) | |
2109 | { | |
2110 | struct mm_slot *mm_slot; | |
2111 | int free = 0; | |
2112 | ||
2113 | spin_lock(&khugepaged_mm_lock); | |
2114 | mm_slot = get_mm_slot(mm); | |
2115 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
43b5fbbd | 2116 | hash_del(&mm_slot->hash); |
ba76149f AA |
2117 | list_del(&mm_slot->mm_node); |
2118 | free = 1; | |
2119 | } | |
d788e80a | 2120 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
2121 | |
2122 | if (free) { | |
ba76149f AA |
2123 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
2124 | free_mm_slot(mm_slot); | |
2125 | mmdrop(mm); | |
2126 | } else if (mm_slot) { | |
ba76149f AA |
2127 | /* |
2128 | * This is required to serialize against | |
2129 | * khugepaged_test_exit() (which is guaranteed to run | |
2130 | * under mmap sem read mode). Stop here (after we | |
2131 | * return all pagetables will be destroyed) until | |
2132 | * khugepaged has finished working on the pagetables | |
2133 | * under the mmap_sem. | |
2134 | */ | |
2135 | down_write(&mm->mmap_sem); | |
2136 | up_write(&mm->mmap_sem); | |
d788e80a | 2137 | } |
ba76149f AA |
2138 | } |
2139 | ||
2140 | static void release_pte_page(struct page *page) | |
2141 | { | |
2142 | /* 0 stands for page_is_file_cache(page) == false */ | |
2143 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2144 | unlock_page(page); | |
2145 | putback_lru_page(page); | |
2146 | } | |
2147 | ||
2148 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
2149 | { | |
2150 | while (--_pte >= pte) { | |
2151 | pte_t pteval = *_pte; | |
2152 | if (!pte_none(pteval)) | |
2153 | release_pte_page(pte_page(pteval)); | |
2154 | } | |
2155 | } | |
2156 | ||
ba76149f AA |
2157 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
2158 | unsigned long address, | |
2159 | pte_t *pte) | |
2160 | { | |
2161 | struct page *page; | |
2162 | pte_t *_pte; | |
344aa35c | 2163 | int referenced = 0, none = 0; |
ba76149f AA |
2164 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
2165 | _pte++, address += PAGE_SIZE) { | |
2166 | pte_t pteval = *_pte; | |
2167 | if (pte_none(pteval)) { | |
2168 | if (++none <= khugepaged_max_ptes_none) | |
2169 | continue; | |
344aa35c | 2170 | else |
ba76149f | 2171 | goto out; |
ba76149f | 2172 | } |
344aa35c | 2173 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 2174 | goto out; |
ba76149f | 2175 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 2176 | if (unlikely(!page)) |
ba76149f | 2177 | goto out; |
344aa35c | 2178 | |
309381fe SL |
2179 | VM_BUG_ON_PAGE(PageCompound(page), page); |
2180 | VM_BUG_ON_PAGE(!PageAnon(page), page); | |
2181 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
ba76149f AA |
2182 | |
2183 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 2184 | if (page_count(page) != 1) |
ba76149f | 2185 | goto out; |
ba76149f AA |
2186 | /* |
2187 | * We can do it before isolate_lru_page because the | |
2188 | * page can't be freed from under us. NOTE: PG_lock | |
2189 | * is needed to serialize against split_huge_page | |
2190 | * when invoked from the VM. | |
2191 | */ | |
344aa35c | 2192 | if (!trylock_page(page)) |
ba76149f | 2193 | goto out; |
ba76149f AA |
2194 | /* |
2195 | * Isolate the page to avoid collapsing an hugepage | |
2196 | * currently in use by the VM. | |
2197 | */ | |
2198 | if (isolate_lru_page(page)) { | |
2199 | unlock_page(page); | |
ba76149f AA |
2200 | goto out; |
2201 | } | |
2202 | /* 0 stands for page_is_file_cache(page) == false */ | |
2203 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
309381fe SL |
2204 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
2205 | VM_BUG_ON_PAGE(PageLRU(page), page); | |
ba76149f AA |
2206 | |
2207 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
2208 | if (pte_young(pteval) || PageReferenced(page) || |
2209 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2210 | referenced = 1; |
2211 | } | |
344aa35c BL |
2212 | if (likely(referenced)) |
2213 | return 1; | |
ba76149f | 2214 | out: |
344aa35c BL |
2215 | release_pte_pages(pte, _pte); |
2216 | return 0; | |
ba76149f AA |
2217 | } |
2218 | ||
2219 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
2220 | struct vm_area_struct *vma, | |
2221 | unsigned long address, | |
2222 | spinlock_t *ptl) | |
2223 | { | |
2224 | pte_t *_pte; | |
2225 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
2226 | pte_t pteval = *_pte; | |
2227 | struct page *src_page; | |
2228 | ||
2229 | if (pte_none(pteval)) { | |
2230 | clear_user_highpage(page, address); | |
2231 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
2232 | } else { | |
2233 | src_page = pte_page(pteval); | |
2234 | copy_user_highpage(page, src_page, address, vma); | |
309381fe | 2235 | VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page); |
ba76149f AA |
2236 | release_pte_page(src_page); |
2237 | /* | |
2238 | * ptl mostly unnecessary, but preempt has to | |
2239 | * be disabled to update the per-cpu stats | |
2240 | * inside page_remove_rmap(). | |
2241 | */ | |
2242 | spin_lock(ptl); | |
2243 | /* | |
2244 | * paravirt calls inside pte_clear here are | |
2245 | * superfluous. | |
2246 | */ | |
2247 | pte_clear(vma->vm_mm, address, _pte); | |
2248 | page_remove_rmap(src_page); | |
2249 | spin_unlock(ptl); | |
2250 | free_page_and_swap_cache(src_page); | |
2251 | } | |
2252 | ||
2253 | address += PAGE_SIZE; | |
2254 | page++; | |
2255 | } | |
2256 | } | |
2257 | ||
26234f36 | 2258 | static void khugepaged_alloc_sleep(void) |
ba76149f | 2259 | { |
26234f36 XG |
2260 | wait_event_freezable_timeout(khugepaged_wait, false, |
2261 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
2262 | } | |
ba76149f | 2263 | |
9f1b868a BL |
2264 | static int khugepaged_node_load[MAX_NUMNODES]; |
2265 | ||
26234f36 | 2266 | #ifdef CONFIG_NUMA |
9f1b868a BL |
2267 | static int khugepaged_find_target_node(void) |
2268 | { | |
2269 | static int last_khugepaged_target_node = NUMA_NO_NODE; | |
2270 | int nid, target_node = 0, max_value = 0; | |
2271 | ||
2272 | /* find first node with max normal pages hit */ | |
2273 | for (nid = 0; nid < MAX_NUMNODES; nid++) | |
2274 | if (khugepaged_node_load[nid] > max_value) { | |
2275 | max_value = khugepaged_node_load[nid]; | |
2276 | target_node = nid; | |
2277 | } | |
2278 | ||
2279 | /* do some balance if several nodes have the same hit record */ | |
2280 | if (target_node <= last_khugepaged_target_node) | |
2281 | for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES; | |
2282 | nid++) | |
2283 | if (max_value == khugepaged_node_load[nid]) { | |
2284 | target_node = nid; | |
2285 | break; | |
2286 | } | |
2287 | ||
2288 | last_khugepaged_target_node = target_node; | |
2289 | return target_node; | |
2290 | } | |
2291 | ||
26234f36 XG |
2292 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) |
2293 | { | |
2294 | if (IS_ERR(*hpage)) { | |
2295 | if (!*wait) | |
2296 | return false; | |
2297 | ||
2298 | *wait = false; | |
e3b4126c | 2299 | *hpage = NULL; |
26234f36 XG |
2300 | khugepaged_alloc_sleep(); |
2301 | } else if (*hpage) { | |
2302 | put_page(*hpage); | |
2303 | *hpage = NULL; | |
2304 | } | |
2305 | ||
2306 | return true; | |
2307 | } | |
2308 | ||
2309 | static struct page | |
2310 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2311 | struct vm_area_struct *vma, unsigned long address, | |
2312 | int node) | |
2313 | { | |
309381fe | 2314 | VM_BUG_ON_PAGE(*hpage, *hpage); |
ce83d217 AA |
2315 | /* |
2316 | * Allocate the page while the vma is still valid and under | |
2317 | * the mmap_sem read mode so there is no memory allocation | |
2318 | * later when we take the mmap_sem in write mode. This is more | |
2319 | * friendly behavior (OTOH it may actually hide bugs) to | |
2320 | * filesystems in userland with daemons allocating memory in | |
2321 | * the userland I/O paths. Allocating memory with the | |
2322 | * mmap_sem in read mode is good idea also to allow greater | |
2323 | * scalability. | |
2324 | */ | |
9f1b868a BL |
2325 | *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask( |
2326 | khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER); | |
692e0b35 AA |
2327 | /* |
2328 | * After allocating the hugepage, release the mmap_sem read lock in | |
2329 | * preparation for taking it in write mode. | |
2330 | */ | |
2331 | up_read(&mm->mmap_sem); | |
26234f36 | 2332 | if (unlikely(!*hpage)) { |
81ab4201 | 2333 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2334 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2335 | return NULL; |
ce83d217 | 2336 | } |
26234f36 | 2337 | |
65b3c07b | 2338 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2339 | return *hpage; |
2340 | } | |
2341 | #else | |
9f1b868a BL |
2342 | static int khugepaged_find_target_node(void) |
2343 | { | |
2344 | return 0; | |
2345 | } | |
2346 | ||
10dc4155 BL |
2347 | static inline struct page *alloc_hugepage(int defrag) |
2348 | { | |
2349 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), | |
2350 | HPAGE_PMD_ORDER); | |
2351 | } | |
2352 | ||
26234f36 XG |
2353 | static struct page *khugepaged_alloc_hugepage(bool *wait) |
2354 | { | |
2355 | struct page *hpage; | |
2356 | ||
2357 | do { | |
2358 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2359 | if (!hpage) { | |
2360 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2361 | if (!*wait) | |
2362 | return NULL; | |
2363 | ||
2364 | *wait = false; | |
2365 | khugepaged_alloc_sleep(); | |
2366 | } else | |
2367 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2368 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2369 | ||
2370 | return hpage; | |
2371 | } | |
2372 | ||
2373 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2374 | { | |
2375 | if (!*hpage) | |
2376 | *hpage = khugepaged_alloc_hugepage(wait); | |
2377 | ||
2378 | if (unlikely(!*hpage)) | |
2379 | return false; | |
2380 | ||
2381 | return true; | |
2382 | } | |
2383 | ||
2384 | static struct page | |
2385 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2386 | struct vm_area_struct *vma, unsigned long address, | |
2387 | int node) | |
2388 | { | |
2389 | up_read(&mm->mmap_sem); | |
2390 | VM_BUG_ON(!*hpage); | |
2391 | return *hpage; | |
2392 | } | |
692e0b35 AA |
2393 | #endif |
2394 | ||
fa475e51 BL |
2395 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2396 | { | |
2397 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2398 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2399 | return false; | |
2400 | ||
2401 | if (!vma->anon_vma || vma->vm_ops) | |
2402 | return false; | |
2403 | if (is_vma_temporary_stack(vma)) | |
2404 | return false; | |
2405 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2406 | return true; | |
2407 | } | |
2408 | ||
26234f36 XG |
2409 | static void collapse_huge_page(struct mm_struct *mm, |
2410 | unsigned long address, | |
2411 | struct page **hpage, | |
2412 | struct vm_area_struct *vma, | |
2413 | int node) | |
2414 | { | |
26234f36 XG |
2415 | pmd_t *pmd, _pmd; |
2416 | pte_t *pte; | |
2417 | pgtable_t pgtable; | |
2418 | struct page *new_page; | |
c4088ebd | 2419 | spinlock_t *pmd_ptl, *pte_ptl; |
26234f36 XG |
2420 | int isolated; |
2421 | unsigned long hstart, hend; | |
2ec74c3e SG |
2422 | unsigned long mmun_start; /* For mmu_notifiers */ |
2423 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2424 | |
2425 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2426 | ||
2427 | /* release the mmap_sem read lock. */ | |
2428 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2429 | if (!new_page) | |
2430 | return; | |
2431 | ||
420256ef | 2432 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2433 | return; |
ba76149f AA |
2434 | |
2435 | /* | |
2436 | * Prevent all access to pagetables with the exception of | |
2437 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2438 | * handled by the anon_vma lock + PG_lock. | |
2439 | */ | |
2440 | down_write(&mm->mmap_sem); | |
2441 | if (unlikely(khugepaged_test_exit(mm))) | |
2442 | goto out; | |
2443 | ||
2444 | vma = find_vma(mm, address); | |
a8f531eb L |
2445 | if (!vma) |
2446 | goto out; | |
ba76149f AA |
2447 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2448 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2449 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2450 | goto out; | |
fa475e51 | 2451 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2452 | goto out; |
6219049a BL |
2453 | pmd = mm_find_pmd(mm, address); |
2454 | if (!pmd) | |
ba76149f | 2455 | goto out; |
6219049a | 2456 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2457 | goto out; |
2458 | ||
4fc3f1d6 | 2459 | anon_vma_lock_write(vma->anon_vma); |
ba76149f AA |
2460 | |
2461 | pte = pte_offset_map(pmd, address); | |
c4088ebd | 2462 | pte_ptl = pte_lockptr(mm, pmd); |
ba76149f | 2463 | |
2ec74c3e SG |
2464 | mmun_start = address; |
2465 | mmun_end = address + HPAGE_PMD_SIZE; | |
2466 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
c4088ebd | 2467 | pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ |
ba76149f AA |
2468 | /* |
2469 | * After this gup_fast can't run anymore. This also removes | |
2470 | * any huge TLB entry from the CPU so we won't allow | |
2471 | * huge and small TLB entries for the same virtual address | |
2472 | * to avoid the risk of CPU bugs in that area. | |
2473 | */ | |
2ec74c3e | 2474 | _pmd = pmdp_clear_flush(vma, address, pmd); |
c4088ebd | 2475 | spin_unlock(pmd_ptl); |
2ec74c3e | 2476 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f | 2477 | |
c4088ebd | 2478 | spin_lock(pte_ptl); |
ba76149f | 2479 | isolated = __collapse_huge_page_isolate(vma, address, pte); |
c4088ebd | 2480 | spin_unlock(pte_ptl); |
ba76149f AA |
2481 | |
2482 | if (unlikely(!isolated)) { | |
453c7192 | 2483 | pte_unmap(pte); |
c4088ebd | 2484 | spin_lock(pmd_ptl); |
ba76149f | 2485 | BUG_ON(!pmd_none(*pmd)); |
7c342512 AK |
2486 | /* |
2487 | * We can only use set_pmd_at when establishing | |
2488 | * hugepmds and never for establishing regular pmds that | |
2489 | * points to regular pagetables. Use pmd_populate for that | |
2490 | */ | |
2491 | pmd_populate(mm, pmd, pmd_pgtable(_pmd)); | |
c4088ebd | 2492 | spin_unlock(pmd_ptl); |
08b52706 | 2493 | anon_vma_unlock_write(vma->anon_vma); |
ce83d217 | 2494 | goto out; |
ba76149f AA |
2495 | } |
2496 | ||
2497 | /* | |
2498 | * All pages are isolated and locked so anon_vma rmap | |
2499 | * can't run anymore. | |
2500 | */ | |
08b52706 | 2501 | anon_vma_unlock_write(vma->anon_vma); |
ba76149f | 2502 | |
c4088ebd | 2503 | __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); |
453c7192 | 2504 | pte_unmap(pte); |
ba76149f AA |
2505 | __SetPageUptodate(new_page); |
2506 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2507 | |
3122359a KS |
2508 | _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); |
2509 | _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); | |
ba76149f AA |
2510 | |
2511 | /* | |
2512 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2513 | * this is needed to avoid the copy_huge_page writes to become | |
2514 | * visible after the set_pmd_at() write. | |
2515 | */ | |
2516 | smp_wmb(); | |
2517 | ||
c4088ebd | 2518 | spin_lock(pmd_ptl); |
ba76149f AA |
2519 | BUG_ON(!pmd_none(*pmd)); |
2520 | page_add_new_anon_rmap(new_page, vma, address); | |
fce144b4 | 2521 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
ba76149f | 2522 | set_pmd_at(mm, address, pmd, _pmd); |
b113da65 | 2523 | update_mmu_cache_pmd(vma, address, pmd); |
c4088ebd | 2524 | spin_unlock(pmd_ptl); |
ba76149f AA |
2525 | |
2526 | *hpage = NULL; | |
420256ef | 2527 | |
ba76149f | 2528 | khugepaged_pages_collapsed++; |
ce83d217 | 2529 | out_up_write: |
ba76149f | 2530 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2531 | return; |
2532 | ||
ce83d217 | 2533 | out: |
678ff896 | 2534 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2535 | goto out_up_write; |
ba76149f AA |
2536 | } |
2537 | ||
2538 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2539 | struct vm_area_struct *vma, | |
2540 | unsigned long address, | |
2541 | struct page **hpage) | |
2542 | { | |
ba76149f AA |
2543 | pmd_t *pmd; |
2544 | pte_t *pte, *_pte; | |
2545 | int ret = 0, referenced = 0, none = 0; | |
2546 | struct page *page; | |
2547 | unsigned long _address; | |
2548 | spinlock_t *ptl; | |
00ef2d2f | 2549 | int node = NUMA_NO_NODE; |
ba76149f AA |
2550 | |
2551 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2552 | ||
6219049a BL |
2553 | pmd = mm_find_pmd(mm, address); |
2554 | if (!pmd) | |
ba76149f | 2555 | goto out; |
6219049a | 2556 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2557 | goto out; |
2558 | ||
9f1b868a | 2559 | memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); |
ba76149f AA |
2560 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); |
2561 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2562 | _pte++, _address += PAGE_SIZE) { | |
2563 | pte_t pteval = *_pte; | |
2564 | if (pte_none(pteval)) { | |
2565 | if (++none <= khugepaged_max_ptes_none) | |
2566 | continue; | |
2567 | else | |
2568 | goto out_unmap; | |
2569 | } | |
2570 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2571 | goto out_unmap; | |
2572 | page = vm_normal_page(vma, _address, pteval); | |
2573 | if (unlikely(!page)) | |
2574 | goto out_unmap; | |
5c4b4be3 | 2575 | /* |
9f1b868a BL |
2576 | * Record which node the original page is from and save this |
2577 | * information to khugepaged_node_load[]. | |
2578 | * Khupaged will allocate hugepage from the node has the max | |
2579 | * hit record. | |
5c4b4be3 | 2580 | */ |
9f1b868a BL |
2581 | node = page_to_nid(page); |
2582 | khugepaged_node_load[node]++; | |
309381fe | 2583 | VM_BUG_ON_PAGE(PageCompound(page), page); |
ba76149f AA |
2584 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) |
2585 | goto out_unmap; | |
2586 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2587 | if (page_count(page) != 1) | |
2588 | goto out_unmap; | |
8ee53820 AA |
2589 | if (pte_young(pteval) || PageReferenced(page) || |
2590 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2591 | referenced = 1; |
2592 | } | |
2593 | if (referenced) | |
2594 | ret = 1; | |
2595 | out_unmap: | |
2596 | pte_unmap_unlock(pte, ptl); | |
9f1b868a BL |
2597 | if (ret) { |
2598 | node = khugepaged_find_target_node(); | |
ce83d217 | 2599 | /* collapse_huge_page will return with the mmap_sem released */ |
5c4b4be3 | 2600 | collapse_huge_page(mm, address, hpage, vma, node); |
9f1b868a | 2601 | } |
ba76149f AA |
2602 | out: |
2603 | return ret; | |
2604 | } | |
2605 | ||
2606 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2607 | { | |
2608 | struct mm_struct *mm = mm_slot->mm; | |
2609 | ||
b9980cdc | 2610 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2611 | |
2612 | if (khugepaged_test_exit(mm)) { | |
2613 | /* free mm_slot */ | |
43b5fbbd | 2614 | hash_del(&mm_slot->hash); |
ba76149f AA |
2615 | list_del(&mm_slot->mm_node); |
2616 | ||
2617 | /* | |
2618 | * Not strictly needed because the mm exited already. | |
2619 | * | |
2620 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2621 | */ | |
2622 | ||
2623 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2624 | free_mm_slot(mm_slot); | |
2625 | mmdrop(mm); | |
2626 | } | |
2627 | } | |
2628 | ||
2629 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2630 | struct page **hpage) | |
2f1da642 HS |
2631 | __releases(&khugepaged_mm_lock) |
2632 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2633 | { |
2634 | struct mm_slot *mm_slot; | |
2635 | struct mm_struct *mm; | |
2636 | struct vm_area_struct *vma; | |
2637 | int progress = 0; | |
2638 | ||
2639 | VM_BUG_ON(!pages); | |
b9980cdc | 2640 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2641 | |
2642 | if (khugepaged_scan.mm_slot) | |
2643 | mm_slot = khugepaged_scan.mm_slot; | |
2644 | else { | |
2645 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2646 | struct mm_slot, mm_node); | |
2647 | khugepaged_scan.address = 0; | |
2648 | khugepaged_scan.mm_slot = mm_slot; | |
2649 | } | |
2650 | spin_unlock(&khugepaged_mm_lock); | |
2651 | ||
2652 | mm = mm_slot->mm; | |
2653 | down_read(&mm->mmap_sem); | |
2654 | if (unlikely(khugepaged_test_exit(mm))) | |
2655 | vma = NULL; | |
2656 | else | |
2657 | vma = find_vma(mm, khugepaged_scan.address); | |
2658 | ||
2659 | progress++; | |
2660 | for (; vma; vma = vma->vm_next) { | |
2661 | unsigned long hstart, hend; | |
2662 | ||
2663 | cond_resched(); | |
2664 | if (unlikely(khugepaged_test_exit(mm))) { | |
2665 | progress++; | |
2666 | break; | |
2667 | } | |
fa475e51 BL |
2668 | if (!hugepage_vma_check(vma)) { |
2669 | skip: | |
ba76149f AA |
2670 | progress++; |
2671 | continue; | |
2672 | } | |
ba76149f AA |
2673 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2674 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2675 | if (hstart >= hend) |
2676 | goto skip; | |
2677 | if (khugepaged_scan.address > hend) | |
2678 | goto skip; | |
ba76149f AA |
2679 | if (khugepaged_scan.address < hstart) |
2680 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2681 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2682 | |
2683 | while (khugepaged_scan.address < hend) { | |
2684 | int ret; | |
2685 | cond_resched(); | |
2686 | if (unlikely(khugepaged_test_exit(mm))) | |
2687 | goto breakouterloop; | |
2688 | ||
2689 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2690 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2691 | hend); | |
2692 | ret = khugepaged_scan_pmd(mm, vma, | |
2693 | khugepaged_scan.address, | |
2694 | hpage); | |
2695 | /* move to next address */ | |
2696 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2697 | progress += HPAGE_PMD_NR; | |
2698 | if (ret) | |
2699 | /* we released mmap_sem so break loop */ | |
2700 | goto breakouterloop_mmap_sem; | |
2701 | if (progress >= pages) | |
2702 | goto breakouterloop; | |
2703 | } | |
2704 | } | |
2705 | breakouterloop: | |
2706 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2707 | breakouterloop_mmap_sem: | |
2708 | ||
2709 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2710 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2711 | /* |
2712 | * Release the current mm_slot if this mm is about to die, or | |
2713 | * if we scanned all vmas of this mm. | |
2714 | */ | |
2715 | if (khugepaged_test_exit(mm) || !vma) { | |
2716 | /* | |
2717 | * Make sure that if mm_users is reaching zero while | |
2718 | * khugepaged runs here, khugepaged_exit will find | |
2719 | * mm_slot not pointing to the exiting mm. | |
2720 | */ | |
2721 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2722 | khugepaged_scan.mm_slot = list_entry( | |
2723 | mm_slot->mm_node.next, | |
2724 | struct mm_slot, mm_node); | |
2725 | khugepaged_scan.address = 0; | |
2726 | } else { | |
2727 | khugepaged_scan.mm_slot = NULL; | |
2728 | khugepaged_full_scans++; | |
2729 | } | |
2730 | ||
2731 | collect_mm_slot(mm_slot); | |
2732 | } | |
2733 | ||
2734 | return progress; | |
2735 | } | |
2736 | ||
2737 | static int khugepaged_has_work(void) | |
2738 | { | |
2739 | return !list_empty(&khugepaged_scan.mm_head) && | |
2740 | khugepaged_enabled(); | |
2741 | } | |
2742 | ||
2743 | static int khugepaged_wait_event(void) | |
2744 | { | |
2745 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2746 | kthread_should_stop(); |
ba76149f AA |
2747 | } |
2748 | ||
d516904b | 2749 | static void khugepaged_do_scan(void) |
ba76149f | 2750 | { |
d516904b | 2751 | struct page *hpage = NULL; |
ba76149f AA |
2752 | unsigned int progress = 0, pass_through_head = 0; |
2753 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2754 | bool wait = true; |
ba76149f AA |
2755 | |
2756 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2757 | ||
2758 | while (progress < pages) { | |
26234f36 | 2759 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2760 | break; |
26234f36 | 2761 | |
420256ef | 2762 | cond_resched(); |
ba76149f | 2763 | |
878aee7d AA |
2764 | if (unlikely(kthread_should_stop() || freezing(current))) |
2765 | break; | |
2766 | ||
ba76149f AA |
2767 | spin_lock(&khugepaged_mm_lock); |
2768 | if (!khugepaged_scan.mm_slot) | |
2769 | pass_through_head++; | |
2770 | if (khugepaged_has_work() && | |
2771 | pass_through_head < 2) | |
2772 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2773 | &hpage); |
ba76149f AA |
2774 | else |
2775 | progress = pages; | |
2776 | spin_unlock(&khugepaged_mm_lock); | |
2777 | } | |
ba76149f | 2778 | |
d516904b XG |
2779 | if (!IS_ERR_OR_NULL(hpage)) |
2780 | put_page(hpage); | |
0bbbc0b3 AA |
2781 | } |
2782 | ||
2017c0bf XG |
2783 | static void khugepaged_wait_work(void) |
2784 | { | |
2785 | try_to_freeze(); | |
2786 | ||
2787 | if (khugepaged_has_work()) { | |
2788 | if (!khugepaged_scan_sleep_millisecs) | |
2789 | return; | |
2790 | ||
2791 | wait_event_freezable_timeout(khugepaged_wait, | |
2792 | kthread_should_stop(), | |
2793 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2794 | return; | |
2795 | } | |
2796 | ||
2797 | if (khugepaged_enabled()) | |
2798 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2799 | } | |
2800 | ||
ba76149f AA |
2801 | static int khugepaged(void *none) |
2802 | { | |
2803 | struct mm_slot *mm_slot; | |
2804 | ||
878aee7d | 2805 | set_freezable(); |
ba76149f AA |
2806 | set_user_nice(current, 19); |
2807 | ||
b7231789 XG |
2808 | while (!kthread_should_stop()) { |
2809 | khugepaged_do_scan(); | |
2810 | khugepaged_wait_work(); | |
2811 | } | |
ba76149f AA |
2812 | |
2813 | spin_lock(&khugepaged_mm_lock); | |
2814 | mm_slot = khugepaged_scan.mm_slot; | |
2815 | khugepaged_scan.mm_slot = NULL; | |
2816 | if (mm_slot) | |
2817 | collect_mm_slot(mm_slot); | |
2818 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2819 | return 0; |
2820 | } | |
2821 | ||
c5a647d0 KS |
2822 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2823 | unsigned long haddr, pmd_t *pmd) | |
2824 | { | |
2825 | struct mm_struct *mm = vma->vm_mm; | |
2826 | pgtable_t pgtable; | |
2827 | pmd_t _pmd; | |
2828 | int i; | |
2829 | ||
2830 | pmdp_clear_flush(vma, haddr, pmd); | |
2831 | /* leave pmd empty until pte is filled */ | |
2832 | ||
6b0b50b0 | 2833 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
c5a647d0 KS |
2834 | pmd_populate(mm, &_pmd, pgtable); |
2835 | ||
2836 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2837 | pte_t *pte, entry; | |
2838 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2839 | entry = pte_mkspecial(entry); | |
2840 | pte = pte_offset_map(&_pmd, haddr); | |
2841 | VM_BUG_ON(!pte_none(*pte)); | |
2842 | set_pte_at(mm, haddr, pte, entry); | |
2843 | pte_unmap(pte); | |
2844 | } | |
2845 | smp_wmb(); /* make pte visible before pmd */ | |
2846 | pmd_populate(mm, pmd, pgtable); | |
97ae1749 | 2847 | put_huge_zero_page(); |
c5a647d0 KS |
2848 | } |
2849 | ||
e180377f KS |
2850 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2851 | pmd_t *pmd) | |
71e3aac0 | 2852 | { |
c4088ebd | 2853 | spinlock_t *ptl; |
71e3aac0 | 2854 | struct page *page; |
e180377f | 2855 | struct mm_struct *mm = vma->vm_mm; |
c5a647d0 KS |
2856 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2857 | unsigned long mmun_start; /* For mmu_notifiers */ | |
2858 | unsigned long mmun_end; /* For mmu_notifiers */ | |
e180377f KS |
2859 | |
2860 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 | 2861 | |
c5a647d0 KS |
2862 | mmun_start = haddr; |
2863 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
750e8165 | 2864 | again: |
c5a647d0 | 2865 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
c4088ebd | 2866 | ptl = pmd_lock(mm, pmd); |
71e3aac0 | 2867 | if (unlikely(!pmd_trans_huge(*pmd))) { |
c4088ebd | 2868 | spin_unlock(ptl); |
c5a647d0 KS |
2869 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2870 | return; | |
2871 | } | |
2872 | if (is_huge_zero_pmd(*pmd)) { | |
2873 | __split_huge_zero_page_pmd(vma, haddr, pmd); | |
c4088ebd | 2874 | spin_unlock(ptl); |
c5a647d0 | 2875 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2876 | return; |
2877 | } | |
2878 | page = pmd_page(*pmd); | |
309381fe | 2879 | VM_BUG_ON_PAGE(!page_count(page), page); |
71e3aac0 | 2880 | get_page(page); |
c4088ebd | 2881 | spin_unlock(ptl); |
c5a647d0 | 2882 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2883 | |
2884 | split_huge_page(page); | |
2885 | ||
2886 | put_page(page); | |
750e8165 HD |
2887 | |
2888 | /* | |
2889 | * We don't always have down_write of mmap_sem here: a racing | |
2890 | * do_huge_pmd_wp_page() might have copied-on-write to another | |
2891 | * huge page before our split_huge_page() got the anon_vma lock. | |
2892 | */ | |
2893 | if (unlikely(pmd_trans_huge(*pmd))) | |
2894 | goto again; | |
71e3aac0 | 2895 | } |
94fcc585 | 2896 | |
e180377f KS |
2897 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2898 | pmd_t *pmd) | |
2899 | { | |
2900 | struct vm_area_struct *vma; | |
2901 | ||
2902 | vma = find_vma(mm, address); | |
2903 | BUG_ON(vma == NULL); | |
2904 | split_huge_page_pmd(vma, address, pmd); | |
2905 | } | |
2906 | ||
94fcc585 AA |
2907 | static void split_huge_page_address(struct mm_struct *mm, |
2908 | unsigned long address) | |
2909 | { | |
94fcc585 AA |
2910 | pmd_t *pmd; |
2911 | ||
2912 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2913 | ||
6219049a BL |
2914 | pmd = mm_find_pmd(mm, address); |
2915 | if (!pmd) | |
94fcc585 AA |
2916 | return; |
2917 | /* | |
2918 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2919 | * materialize from under us. | |
2920 | */ | |
e180377f | 2921 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2922 | } |
2923 | ||
2924 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2925 | unsigned long start, | |
2926 | unsigned long end, | |
2927 | long adjust_next) | |
2928 | { | |
2929 | /* | |
2930 | * If the new start address isn't hpage aligned and it could | |
2931 | * previously contain an hugepage: check if we need to split | |
2932 | * an huge pmd. | |
2933 | */ | |
2934 | if (start & ~HPAGE_PMD_MASK && | |
2935 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2936 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2937 | split_huge_page_address(vma->vm_mm, start); | |
2938 | ||
2939 | /* | |
2940 | * If the new end address isn't hpage aligned and it could | |
2941 | * previously contain an hugepage: check if we need to split | |
2942 | * an huge pmd. | |
2943 | */ | |
2944 | if (end & ~HPAGE_PMD_MASK && | |
2945 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2946 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2947 | split_huge_page_address(vma->vm_mm, end); | |
2948 | ||
2949 | /* | |
2950 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2951 | * vm_next->vm_start isn't page aligned and it could previously | |
2952 | * contain an hugepage: check if we need to split an huge pmd. | |
2953 | */ | |
2954 | if (adjust_next > 0) { | |
2955 | struct vm_area_struct *next = vma->vm_next; | |
2956 | unsigned long nstart = next->vm_start; | |
2957 | nstart += adjust_next << PAGE_SHIFT; | |
2958 | if (nstart & ~HPAGE_PMD_MASK && | |
2959 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2960 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2961 | split_huge_page_address(next->vm_mm, nstart); | |
2962 | } | |
2963 | } |