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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 | ||
42aa83cb HP |
133 | if (recommended_min > min_free_kbytes) { |
134 | if (user_min_free_kbytes >= 0) | |
135 | pr_info("raising min_free_kbytes from %d to %lu " | |
136 | "to help transparent hugepage allocations\n", | |
137 | min_free_kbytes, recommended_min); | |
138 | ||
f000565a | 139 | min_free_kbytes = recommended_min; |
42aa83cb | 140 | } |
f000565a AA |
141 | setup_per_zone_wmarks(); |
142 | return 0; | |
143 | } | |
144 | late_initcall(set_recommended_min_free_kbytes); | |
145 | ||
ba76149f AA |
146 | static int start_khugepaged(void) |
147 | { | |
148 | int err = 0; | |
149 | if (khugepaged_enabled()) { | |
ba76149f AA |
150 | if (!khugepaged_thread) |
151 | khugepaged_thread = kthread_run(khugepaged, NULL, | |
152 | "khugepaged"); | |
153 | if (unlikely(IS_ERR(khugepaged_thread))) { | |
154 | printk(KERN_ERR | |
155 | "khugepaged: kthread_run(khugepaged) failed\n"); | |
156 | err = PTR_ERR(khugepaged_thread); | |
157 | khugepaged_thread = NULL; | |
158 | } | |
911891af XG |
159 | |
160 | if (!list_empty(&khugepaged_scan.mm_head)) | |
ba76149f | 161 | wake_up_interruptible(&khugepaged_wait); |
f000565a AA |
162 | |
163 | set_recommended_min_free_kbytes(); | |
911891af | 164 | } else if (khugepaged_thread) { |
911891af XG |
165 | kthread_stop(khugepaged_thread); |
166 | khugepaged_thread = NULL; | |
167 | } | |
637e3a27 | 168 | |
ba76149f AA |
169 | return err; |
170 | } | |
71e3aac0 | 171 | |
97ae1749 | 172 | static atomic_t huge_zero_refcount; |
5918d10a | 173 | static struct page *huge_zero_page __read_mostly; |
97ae1749 | 174 | |
5918d10a | 175 | static inline bool is_huge_zero_page(struct page *page) |
4a6c1297 | 176 | { |
5918d10a | 177 | return ACCESS_ONCE(huge_zero_page) == page; |
97ae1749 | 178 | } |
4a6c1297 | 179 | |
97ae1749 KS |
180 | static inline bool is_huge_zero_pmd(pmd_t pmd) |
181 | { | |
5918d10a | 182 | return is_huge_zero_page(pmd_page(pmd)); |
97ae1749 KS |
183 | } |
184 | ||
5918d10a | 185 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
186 | { |
187 | struct page *zero_page; | |
188 | retry: | |
189 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
5918d10a | 190 | return ACCESS_ONCE(huge_zero_page); |
97ae1749 KS |
191 | |
192 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 193 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
194 | if (!zero_page) { |
195 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 196 | return NULL; |
d8a8e1f0 KS |
197 | } |
198 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 199 | preempt_disable(); |
5918d10a | 200 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 KS |
201 | preempt_enable(); |
202 | __free_page(zero_page); | |
203 | goto retry; | |
204 | } | |
205 | ||
206 | /* We take additional reference here. It will be put back by shrinker */ | |
207 | atomic_set(&huge_zero_refcount, 2); | |
208 | preempt_enable(); | |
5918d10a | 209 | return ACCESS_ONCE(huge_zero_page); |
4a6c1297 KS |
210 | } |
211 | ||
97ae1749 | 212 | static void put_huge_zero_page(void) |
4a6c1297 | 213 | { |
97ae1749 KS |
214 | /* |
215 | * Counter should never go to zero here. Only shrinker can put | |
216 | * last reference. | |
217 | */ | |
218 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
219 | } |
220 | ||
48896466 GC |
221 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
222 | struct shrink_control *sc) | |
4a6c1297 | 223 | { |
48896466 GC |
224 | /* we can free zero page only if last reference remains */ |
225 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
226 | } | |
97ae1749 | 227 | |
48896466 GC |
228 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
229 | struct shrink_control *sc) | |
230 | { | |
97ae1749 | 231 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
232 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
233 | BUG_ON(zero_page == NULL); | |
234 | __free_page(zero_page); | |
48896466 | 235 | return HPAGE_PMD_NR; |
97ae1749 KS |
236 | } |
237 | ||
238 | return 0; | |
4a6c1297 KS |
239 | } |
240 | ||
97ae1749 | 241 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
242 | .count_objects = shrink_huge_zero_page_count, |
243 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
244 | .seeks = DEFAULT_SEEKS, |
245 | }; | |
246 | ||
71e3aac0 | 247 | #ifdef CONFIG_SYSFS |
ba76149f | 248 | |
71e3aac0 AA |
249 | static ssize_t double_flag_show(struct kobject *kobj, |
250 | struct kobj_attribute *attr, char *buf, | |
251 | enum transparent_hugepage_flag enabled, | |
252 | enum transparent_hugepage_flag req_madv) | |
253 | { | |
254 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
255 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
256 | return sprintf(buf, "[always] madvise never\n"); | |
257 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
258 | return sprintf(buf, "always [madvise] never\n"); | |
259 | else | |
260 | return sprintf(buf, "always madvise [never]\n"); | |
261 | } | |
262 | static ssize_t double_flag_store(struct kobject *kobj, | |
263 | struct kobj_attribute *attr, | |
264 | const char *buf, size_t count, | |
265 | enum transparent_hugepage_flag enabled, | |
266 | enum transparent_hugepage_flag req_madv) | |
267 | { | |
268 | if (!memcmp("always", buf, | |
269 | min(sizeof("always")-1, count))) { | |
270 | set_bit(enabled, &transparent_hugepage_flags); | |
271 | clear_bit(req_madv, &transparent_hugepage_flags); | |
272 | } else if (!memcmp("madvise", buf, | |
273 | min(sizeof("madvise")-1, count))) { | |
274 | clear_bit(enabled, &transparent_hugepage_flags); | |
275 | set_bit(req_madv, &transparent_hugepage_flags); | |
276 | } else if (!memcmp("never", buf, | |
277 | min(sizeof("never")-1, count))) { | |
278 | clear_bit(enabled, &transparent_hugepage_flags); | |
279 | clear_bit(req_madv, &transparent_hugepage_flags); | |
280 | } else | |
281 | return -EINVAL; | |
282 | ||
283 | return count; | |
284 | } | |
285 | ||
286 | static ssize_t enabled_show(struct kobject *kobj, | |
287 | struct kobj_attribute *attr, char *buf) | |
288 | { | |
289 | return double_flag_show(kobj, attr, buf, | |
290 | TRANSPARENT_HUGEPAGE_FLAG, | |
291 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
292 | } | |
293 | static ssize_t enabled_store(struct kobject *kobj, | |
294 | struct kobj_attribute *attr, | |
295 | const char *buf, size_t count) | |
296 | { | |
ba76149f AA |
297 | ssize_t ret; |
298 | ||
299 | ret = double_flag_store(kobj, attr, buf, count, | |
300 | TRANSPARENT_HUGEPAGE_FLAG, | |
301 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
302 | ||
303 | if (ret > 0) { | |
911891af XG |
304 | int err; |
305 | ||
306 | mutex_lock(&khugepaged_mutex); | |
307 | err = start_khugepaged(); | |
308 | mutex_unlock(&khugepaged_mutex); | |
309 | ||
ba76149f AA |
310 | if (err) |
311 | ret = err; | |
312 | } | |
313 | ||
314 | return ret; | |
71e3aac0 AA |
315 | } |
316 | static struct kobj_attribute enabled_attr = | |
317 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
318 | ||
319 | static ssize_t single_flag_show(struct kobject *kobj, | |
320 | struct kobj_attribute *attr, char *buf, | |
321 | enum transparent_hugepage_flag flag) | |
322 | { | |
e27e6151 BH |
323 | return sprintf(buf, "%d\n", |
324 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 325 | } |
e27e6151 | 326 | |
71e3aac0 AA |
327 | static ssize_t single_flag_store(struct kobject *kobj, |
328 | struct kobj_attribute *attr, | |
329 | const char *buf, size_t count, | |
330 | enum transparent_hugepage_flag flag) | |
331 | { | |
e27e6151 BH |
332 | unsigned long value; |
333 | int ret; | |
334 | ||
335 | ret = kstrtoul(buf, 10, &value); | |
336 | if (ret < 0) | |
337 | return ret; | |
338 | if (value > 1) | |
339 | return -EINVAL; | |
340 | ||
341 | if (value) | |
71e3aac0 | 342 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 343 | else |
71e3aac0 | 344 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
345 | |
346 | return count; | |
347 | } | |
348 | ||
349 | /* | |
350 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
351 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
352 | * memory just to allocate one more hugepage. | |
353 | */ | |
354 | static ssize_t defrag_show(struct kobject *kobj, | |
355 | struct kobj_attribute *attr, char *buf) | |
356 | { | |
357 | return double_flag_show(kobj, attr, buf, | |
358 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
359 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
360 | } | |
361 | static ssize_t defrag_store(struct kobject *kobj, | |
362 | struct kobj_attribute *attr, | |
363 | const char *buf, size_t count) | |
364 | { | |
365 | return double_flag_store(kobj, attr, buf, count, | |
366 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
367 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
368 | } | |
369 | static struct kobj_attribute defrag_attr = | |
370 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
371 | ||
79da5407 KS |
372 | static ssize_t use_zero_page_show(struct kobject *kobj, |
373 | struct kobj_attribute *attr, char *buf) | |
374 | { | |
375 | return single_flag_show(kobj, attr, buf, | |
376 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
377 | } | |
378 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
379 | struct kobj_attribute *attr, const char *buf, size_t count) | |
380 | { | |
381 | return single_flag_store(kobj, attr, buf, count, | |
382 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
383 | } | |
384 | static struct kobj_attribute use_zero_page_attr = | |
385 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
71e3aac0 AA |
386 | #ifdef CONFIG_DEBUG_VM |
387 | static ssize_t debug_cow_show(struct kobject *kobj, | |
388 | struct kobj_attribute *attr, char *buf) | |
389 | { | |
390 | return single_flag_show(kobj, attr, buf, | |
391 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
392 | } | |
393 | static ssize_t debug_cow_store(struct kobject *kobj, | |
394 | struct kobj_attribute *attr, | |
395 | const char *buf, size_t count) | |
396 | { | |
397 | return single_flag_store(kobj, attr, buf, count, | |
398 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
399 | } | |
400 | static struct kobj_attribute debug_cow_attr = | |
401 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
402 | #endif /* CONFIG_DEBUG_VM */ | |
403 | ||
404 | static struct attribute *hugepage_attr[] = { | |
405 | &enabled_attr.attr, | |
406 | &defrag_attr.attr, | |
79da5407 | 407 | &use_zero_page_attr.attr, |
71e3aac0 AA |
408 | #ifdef CONFIG_DEBUG_VM |
409 | &debug_cow_attr.attr, | |
410 | #endif | |
411 | NULL, | |
412 | }; | |
413 | ||
414 | static struct attribute_group hugepage_attr_group = { | |
415 | .attrs = hugepage_attr, | |
ba76149f AA |
416 | }; |
417 | ||
418 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
419 | struct kobj_attribute *attr, | |
420 | char *buf) | |
421 | { | |
422 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
423 | } | |
424 | ||
425 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
426 | struct kobj_attribute *attr, | |
427 | const char *buf, size_t count) | |
428 | { | |
429 | unsigned long msecs; | |
430 | int err; | |
431 | ||
3dbb95f7 | 432 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
433 | if (err || msecs > UINT_MAX) |
434 | return -EINVAL; | |
435 | ||
436 | khugepaged_scan_sleep_millisecs = msecs; | |
437 | wake_up_interruptible(&khugepaged_wait); | |
438 | ||
439 | return count; | |
440 | } | |
441 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
442 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
443 | scan_sleep_millisecs_store); | |
444 | ||
445 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
446 | struct kobj_attribute *attr, | |
447 | char *buf) | |
448 | { | |
449 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
450 | } | |
451 | ||
452 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
453 | struct kobj_attribute *attr, | |
454 | const char *buf, size_t count) | |
455 | { | |
456 | unsigned long msecs; | |
457 | int err; | |
458 | ||
3dbb95f7 | 459 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
460 | if (err || msecs > UINT_MAX) |
461 | return -EINVAL; | |
462 | ||
463 | khugepaged_alloc_sleep_millisecs = msecs; | |
464 | wake_up_interruptible(&khugepaged_wait); | |
465 | ||
466 | return count; | |
467 | } | |
468 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
469 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
470 | alloc_sleep_millisecs_store); | |
471 | ||
472 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
473 | struct kobj_attribute *attr, | |
474 | char *buf) | |
475 | { | |
476 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
477 | } | |
478 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
479 | struct kobj_attribute *attr, | |
480 | const char *buf, size_t count) | |
481 | { | |
482 | int err; | |
483 | unsigned long pages; | |
484 | ||
3dbb95f7 | 485 | err = kstrtoul(buf, 10, &pages); |
ba76149f AA |
486 | if (err || !pages || pages > UINT_MAX) |
487 | return -EINVAL; | |
488 | ||
489 | khugepaged_pages_to_scan = pages; | |
490 | ||
491 | return count; | |
492 | } | |
493 | static struct kobj_attribute pages_to_scan_attr = | |
494 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
495 | pages_to_scan_store); | |
496 | ||
497 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
498 | struct kobj_attribute *attr, | |
499 | char *buf) | |
500 | { | |
501 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
502 | } | |
503 | static struct kobj_attribute pages_collapsed_attr = | |
504 | __ATTR_RO(pages_collapsed); | |
505 | ||
506 | static ssize_t full_scans_show(struct kobject *kobj, | |
507 | struct kobj_attribute *attr, | |
508 | char *buf) | |
509 | { | |
510 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
511 | } | |
512 | static struct kobj_attribute full_scans_attr = | |
513 | __ATTR_RO(full_scans); | |
514 | ||
515 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
516 | struct kobj_attribute *attr, char *buf) | |
517 | { | |
518 | return single_flag_show(kobj, attr, buf, | |
519 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
520 | } | |
521 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
522 | struct kobj_attribute *attr, | |
523 | const char *buf, size_t count) | |
524 | { | |
525 | return single_flag_store(kobj, attr, buf, count, | |
526 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
527 | } | |
528 | static struct kobj_attribute khugepaged_defrag_attr = | |
529 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
530 | khugepaged_defrag_store); | |
531 | ||
532 | /* | |
533 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
534 | * any unmapped ptes in turn potentially increasing the memory | |
535 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
536 | * reduce the available free memory in the system as it | |
537 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
538 | * free memory in the system during the khugepaged scan. | |
539 | */ | |
540 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
541 | struct kobj_attribute *attr, | |
542 | char *buf) | |
543 | { | |
544 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
545 | } | |
546 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
547 | struct kobj_attribute *attr, | |
548 | const char *buf, size_t count) | |
549 | { | |
550 | int err; | |
551 | unsigned long max_ptes_none; | |
552 | ||
3dbb95f7 | 553 | err = kstrtoul(buf, 10, &max_ptes_none); |
ba76149f AA |
554 | if (err || max_ptes_none > HPAGE_PMD_NR-1) |
555 | return -EINVAL; | |
556 | ||
557 | khugepaged_max_ptes_none = max_ptes_none; | |
558 | ||
559 | return count; | |
560 | } | |
561 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
562 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
563 | khugepaged_max_ptes_none_store); | |
564 | ||
565 | static struct attribute *khugepaged_attr[] = { | |
566 | &khugepaged_defrag_attr.attr, | |
567 | &khugepaged_max_ptes_none_attr.attr, | |
568 | &pages_to_scan_attr.attr, | |
569 | &pages_collapsed_attr.attr, | |
570 | &full_scans_attr.attr, | |
571 | &scan_sleep_millisecs_attr.attr, | |
572 | &alloc_sleep_millisecs_attr.attr, | |
573 | NULL, | |
574 | }; | |
575 | ||
576 | static struct attribute_group khugepaged_attr_group = { | |
577 | .attrs = khugepaged_attr, | |
578 | .name = "khugepaged", | |
71e3aac0 | 579 | }; |
71e3aac0 | 580 | |
569e5590 | 581 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 582 | { |
71e3aac0 AA |
583 | int err; |
584 | ||
569e5590 SL |
585 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
586 | if (unlikely(!*hugepage_kobj)) { | |
2c79737a | 587 | printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n"); |
569e5590 | 588 | return -ENOMEM; |
ba76149f AA |
589 | } |
590 | ||
569e5590 | 591 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 592 | if (err) { |
2c79737a | 593 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 594 | goto delete_obj; |
ba76149f AA |
595 | } |
596 | ||
569e5590 | 597 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 598 | if (err) { |
2c79737a | 599 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 600 | goto remove_hp_group; |
ba76149f | 601 | } |
569e5590 SL |
602 | |
603 | return 0; | |
604 | ||
605 | remove_hp_group: | |
606 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
607 | delete_obj: | |
608 | kobject_put(*hugepage_kobj); | |
609 | return err; | |
610 | } | |
611 | ||
612 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
613 | { | |
614 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
615 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
616 | kobject_put(hugepage_kobj); | |
617 | } | |
618 | #else | |
619 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
620 | { | |
621 | return 0; | |
622 | } | |
623 | ||
624 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
625 | { | |
626 | } | |
627 | #endif /* CONFIG_SYSFS */ | |
628 | ||
629 | static int __init hugepage_init(void) | |
630 | { | |
631 | int err; | |
632 | struct kobject *hugepage_kobj; | |
633 | ||
634 | if (!has_transparent_hugepage()) { | |
635 | transparent_hugepage_flags = 0; | |
636 | return -EINVAL; | |
637 | } | |
638 | ||
639 | err = hugepage_init_sysfs(&hugepage_kobj); | |
640 | if (err) | |
641 | return err; | |
ba76149f AA |
642 | |
643 | err = khugepaged_slab_init(); | |
644 | if (err) | |
645 | goto out; | |
646 | ||
97ae1749 KS |
647 | register_shrinker(&huge_zero_page_shrinker); |
648 | ||
97562cd2 RR |
649 | /* |
650 | * By default disable transparent hugepages on smaller systems, | |
651 | * where the extra memory used could hurt more than TLB overhead | |
652 | * is likely to save. The admin can still enable it through /sys. | |
653 | */ | |
654 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
655 | transparent_hugepage_flags = 0; | |
656 | ||
ba76149f AA |
657 | start_khugepaged(); |
658 | ||
569e5590 | 659 | return 0; |
ba76149f | 660 | out: |
569e5590 | 661 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 662 | return err; |
71e3aac0 | 663 | } |
a64fb3cd | 664 | subsys_initcall(hugepage_init); |
71e3aac0 AA |
665 | |
666 | static int __init setup_transparent_hugepage(char *str) | |
667 | { | |
668 | int ret = 0; | |
669 | if (!str) | |
670 | goto out; | |
671 | if (!strcmp(str, "always")) { | |
672 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
673 | &transparent_hugepage_flags); | |
674 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
675 | &transparent_hugepage_flags); | |
676 | ret = 1; | |
677 | } else if (!strcmp(str, "madvise")) { | |
678 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
679 | &transparent_hugepage_flags); | |
680 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
681 | &transparent_hugepage_flags); | |
682 | ret = 1; | |
683 | } else if (!strcmp(str, "never")) { | |
684 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
685 | &transparent_hugepage_flags); | |
686 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
687 | &transparent_hugepage_flags); | |
688 | ret = 1; | |
689 | } | |
690 | out: | |
691 | if (!ret) | |
692 | printk(KERN_WARNING | |
693 | "transparent_hugepage= cannot parse, ignored\n"); | |
694 | return ret; | |
695 | } | |
696 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
697 | ||
b32967ff | 698 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
699 | { |
700 | if (likely(vma->vm_flags & VM_WRITE)) | |
701 | pmd = pmd_mkwrite(pmd); | |
702 | return pmd; | |
703 | } | |
704 | ||
3122359a | 705 | static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) |
b3092b3b BL |
706 | { |
707 | pmd_t entry; | |
3122359a | 708 | entry = mk_pmd(page, prot); |
b3092b3b BL |
709 | entry = pmd_mkhuge(entry); |
710 | return entry; | |
711 | } | |
712 | ||
71e3aac0 AA |
713 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
714 | struct vm_area_struct *vma, | |
715 | unsigned long haddr, pmd_t *pmd, | |
716 | struct page *page) | |
717 | { | |
71e3aac0 | 718 | pgtable_t pgtable; |
c4088ebd | 719 | spinlock_t *ptl; |
71e3aac0 | 720 | |
309381fe | 721 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
71e3aac0 | 722 | pgtable = pte_alloc_one(mm, haddr); |
edad9d2c | 723 | if (unlikely(!pgtable)) |
71e3aac0 | 724 | return VM_FAULT_OOM; |
71e3aac0 AA |
725 | |
726 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
52f37629 MK |
727 | /* |
728 | * The memory barrier inside __SetPageUptodate makes sure that | |
729 | * clear_huge_page writes become visible before the set_pmd_at() | |
730 | * write. | |
731 | */ | |
71e3aac0 AA |
732 | __SetPageUptodate(page); |
733 | ||
c4088ebd | 734 | ptl = pmd_lock(mm, pmd); |
71e3aac0 | 735 | if (unlikely(!pmd_none(*pmd))) { |
c4088ebd | 736 | spin_unlock(ptl); |
b9bbfbe3 | 737 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
738 | put_page(page); |
739 | pte_free(mm, pgtable); | |
740 | } else { | |
741 | pmd_t entry; | |
3122359a KS |
742 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
743 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
71e3aac0 | 744 | page_add_new_anon_rmap(page, vma, haddr); |
6b0b50b0 | 745 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
71e3aac0 | 746 | set_pmd_at(mm, haddr, pmd, entry); |
71e3aac0 | 747 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
e1f56c89 | 748 | atomic_long_inc(&mm->nr_ptes); |
c4088ebd | 749 | spin_unlock(ptl); |
71e3aac0 AA |
750 | } |
751 | ||
aa2e878e | 752 | return 0; |
71e3aac0 AA |
753 | } |
754 | ||
cc5d462f | 755 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 756 | { |
cc5d462f | 757 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
758 | } |
759 | ||
760 | static inline struct page *alloc_hugepage_vma(int defrag, | |
761 | struct vm_area_struct *vma, | |
cc5d462f AK |
762 | unsigned long haddr, int nd, |
763 | gfp_t extra_gfp) | |
0bbbc0b3 | 764 | { |
cc5d462f | 765 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 766 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
767 | } |
768 | ||
c4088ebd | 769 | /* Caller must hold page table lock. */ |
3ea41e62 | 770 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 771 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 772 | struct page *zero_page) |
fc9fe822 KS |
773 | { |
774 | pmd_t entry; | |
3ea41e62 KS |
775 | if (!pmd_none(*pmd)) |
776 | return false; | |
5918d10a | 777 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 KS |
778 | entry = pmd_wrprotect(entry); |
779 | entry = pmd_mkhuge(entry); | |
6b0b50b0 | 780 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 781 | set_pmd_at(mm, haddr, pmd, entry); |
e1f56c89 | 782 | atomic_long_inc(&mm->nr_ptes); |
3ea41e62 | 783 | return true; |
fc9fe822 KS |
784 | } |
785 | ||
71e3aac0 AA |
786 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
787 | unsigned long address, pmd_t *pmd, | |
788 | unsigned int flags) | |
789 | { | |
790 | struct page *page; | |
791 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
71e3aac0 | 792 | |
128ec037 | 793 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 794 | return VM_FAULT_FALLBACK; |
128ec037 KS |
795 | if (unlikely(anon_vma_prepare(vma))) |
796 | return VM_FAULT_OOM; | |
797 | if (unlikely(khugepaged_enter(vma))) | |
798 | return VM_FAULT_OOM; | |
799 | if (!(flags & FAULT_FLAG_WRITE) && | |
800 | transparent_hugepage_use_zero_page()) { | |
c4088ebd | 801 | spinlock_t *ptl; |
128ec037 KS |
802 | pgtable_t pgtable; |
803 | struct page *zero_page; | |
804 | bool set; | |
805 | pgtable = pte_alloc_one(mm, haddr); | |
806 | if (unlikely(!pgtable)) | |
ba76149f | 807 | return VM_FAULT_OOM; |
128ec037 KS |
808 | zero_page = get_huge_zero_page(); |
809 | if (unlikely(!zero_page)) { | |
810 | pte_free(mm, pgtable); | |
81ab4201 | 811 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 812 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 813 | } |
c4088ebd | 814 | ptl = pmd_lock(mm, pmd); |
128ec037 KS |
815 | set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, |
816 | zero_page); | |
c4088ebd | 817 | spin_unlock(ptl); |
128ec037 KS |
818 | if (!set) { |
819 | pte_free(mm, pgtable); | |
820 | put_huge_zero_page(); | |
edad9d2c | 821 | } |
edad9d2c | 822 | return 0; |
71e3aac0 | 823 | } |
128ec037 KS |
824 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
825 | vma, haddr, numa_node_id(), 0); | |
826 | if (unlikely(!page)) { | |
827 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 828 | return VM_FAULT_FALLBACK; |
128ec037 | 829 | } |
128ec037 KS |
830 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
831 | put_page(page); | |
17766dde | 832 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 833 | return VM_FAULT_FALLBACK; |
128ec037 KS |
834 | } |
835 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) { | |
836 | mem_cgroup_uncharge_page(page); | |
837 | put_page(page); | |
17766dde | 838 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 839 | return VM_FAULT_FALLBACK; |
128ec037 KS |
840 | } |
841 | ||
17766dde | 842 | count_vm_event(THP_FAULT_ALLOC); |
128ec037 | 843 | return 0; |
71e3aac0 AA |
844 | } |
845 | ||
846 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
847 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
848 | struct vm_area_struct *vma) | |
849 | { | |
c4088ebd | 850 | spinlock_t *dst_ptl, *src_ptl; |
71e3aac0 AA |
851 | struct page *src_page; |
852 | pmd_t pmd; | |
853 | pgtable_t pgtable; | |
854 | int ret; | |
855 | ||
856 | ret = -ENOMEM; | |
857 | pgtable = pte_alloc_one(dst_mm, addr); | |
858 | if (unlikely(!pgtable)) | |
859 | goto out; | |
860 | ||
c4088ebd KS |
861 | dst_ptl = pmd_lock(dst_mm, dst_pmd); |
862 | src_ptl = pmd_lockptr(src_mm, src_pmd); | |
863 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); | |
71e3aac0 AA |
864 | |
865 | ret = -EAGAIN; | |
866 | pmd = *src_pmd; | |
867 | if (unlikely(!pmd_trans_huge(pmd))) { | |
868 | pte_free(dst_mm, pgtable); | |
869 | goto out_unlock; | |
870 | } | |
fc9fe822 | 871 | /* |
c4088ebd | 872 | * When page table lock is held, the huge zero pmd should not be |
fc9fe822 KS |
873 | * under splitting since we don't split the page itself, only pmd to |
874 | * a page table. | |
875 | */ | |
876 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 877 | struct page *zero_page; |
3ea41e62 | 878 | bool set; |
97ae1749 KS |
879 | /* |
880 | * get_huge_zero_page() will never allocate a new page here, | |
881 | * since we already have a zero page to copy. It just takes a | |
882 | * reference. | |
883 | */ | |
5918d10a | 884 | zero_page = get_huge_zero_page(); |
3ea41e62 | 885 | set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 886 | zero_page); |
3ea41e62 | 887 | BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ |
fc9fe822 KS |
888 | ret = 0; |
889 | goto out_unlock; | |
890 | } | |
de466bd6 | 891 | |
71e3aac0 AA |
892 | if (unlikely(pmd_trans_splitting(pmd))) { |
893 | /* split huge page running from under us */ | |
c4088ebd KS |
894 | spin_unlock(src_ptl); |
895 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
896 | pte_free(dst_mm, pgtable); |
897 | ||
898 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
899 | goto out; | |
900 | } | |
901 | src_page = pmd_page(pmd); | |
309381fe | 902 | VM_BUG_ON_PAGE(!PageHead(src_page), src_page); |
71e3aac0 AA |
903 | get_page(src_page); |
904 | page_dup_rmap(src_page); | |
905 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
906 | ||
907 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
908 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
6b0b50b0 | 909 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 910 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
e1f56c89 | 911 | atomic_long_inc(&dst_mm->nr_ptes); |
71e3aac0 AA |
912 | |
913 | ret = 0; | |
914 | out_unlock: | |
c4088ebd KS |
915 | spin_unlock(src_ptl); |
916 | spin_unlock(dst_ptl); | |
71e3aac0 AA |
917 | out: |
918 | return ret; | |
919 | } | |
920 | ||
a1dd450b WD |
921 | void huge_pmd_set_accessed(struct mm_struct *mm, |
922 | struct vm_area_struct *vma, | |
923 | unsigned long address, | |
924 | pmd_t *pmd, pmd_t orig_pmd, | |
925 | int dirty) | |
926 | { | |
c4088ebd | 927 | spinlock_t *ptl; |
a1dd450b WD |
928 | pmd_t entry; |
929 | unsigned long haddr; | |
930 | ||
c4088ebd | 931 | ptl = pmd_lock(mm, pmd); |
a1dd450b WD |
932 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
933 | goto unlock; | |
934 | ||
935 | entry = pmd_mkyoung(orig_pmd); | |
936 | haddr = address & HPAGE_PMD_MASK; | |
937 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
938 | update_mmu_cache_pmd(vma, address, pmd); | |
939 | ||
940 | unlock: | |
c4088ebd | 941 | spin_unlock(ptl); |
a1dd450b WD |
942 | } |
943 | ||
71e3aac0 AA |
944 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
945 | struct vm_area_struct *vma, | |
946 | unsigned long address, | |
947 | pmd_t *pmd, pmd_t orig_pmd, | |
948 | struct page *page, | |
949 | unsigned long haddr) | |
950 | { | |
c4088ebd | 951 | spinlock_t *ptl; |
71e3aac0 AA |
952 | pgtable_t pgtable; |
953 | pmd_t _pmd; | |
954 | int ret = 0, i; | |
955 | struct page **pages; | |
2ec74c3e SG |
956 | unsigned long mmun_start; /* For mmu_notifiers */ |
957 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
958 | |
959 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
960 | GFP_KERNEL); | |
961 | if (unlikely(!pages)) { | |
962 | ret |= VM_FAULT_OOM; | |
963 | goto out; | |
964 | } | |
965 | ||
966 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
967 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
968 | __GFP_OTHER_NODE, | |
19ee151e | 969 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
970 | if (unlikely(!pages[i] || |
971 | mem_cgroup_newpage_charge(pages[i], mm, | |
972 | GFP_KERNEL))) { | |
973 | if (pages[i]) | |
71e3aac0 | 974 | put_page(pages[i]); |
b9bbfbe3 AA |
975 | mem_cgroup_uncharge_start(); |
976 | while (--i >= 0) { | |
977 | mem_cgroup_uncharge_page(pages[i]); | |
978 | put_page(pages[i]); | |
979 | } | |
980 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
981 | kfree(pages); |
982 | ret |= VM_FAULT_OOM; | |
983 | goto out; | |
984 | } | |
985 | } | |
986 | ||
987 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
988 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 989 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
990 | __SetPageUptodate(pages[i]); |
991 | cond_resched(); | |
992 | } | |
993 | ||
2ec74c3e SG |
994 | mmun_start = haddr; |
995 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
996 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
997 | ||
c4088ebd | 998 | ptl = pmd_lock(mm, pmd); |
71e3aac0 AA |
999 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
1000 | goto out_free_pages; | |
309381fe | 1001 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 | 1002 | |
2ec74c3e | 1003 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1004 | /* leave pmd empty until pte is filled */ |
1005 | ||
6b0b50b0 | 1006 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1007 | pmd_populate(mm, &_pmd, pgtable); |
1008 | ||
1009 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1010 | pte_t *pte, entry; | |
1011 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
1012 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1013 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
1014 | pte = pte_offset_map(&_pmd, haddr); | |
1015 | VM_BUG_ON(!pte_none(*pte)); | |
1016 | set_pte_at(mm, haddr, pte, entry); | |
1017 | pte_unmap(pte); | |
1018 | } | |
1019 | kfree(pages); | |
1020 | ||
71e3aac0 AA |
1021 | smp_wmb(); /* make pte visible before pmd */ |
1022 | pmd_populate(mm, pmd, pgtable); | |
1023 | page_remove_rmap(page); | |
c4088ebd | 1024 | spin_unlock(ptl); |
71e3aac0 | 1025 | |
2ec74c3e SG |
1026 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1027 | ||
71e3aac0 AA |
1028 | ret |= VM_FAULT_WRITE; |
1029 | put_page(page); | |
1030 | ||
1031 | out: | |
1032 | return ret; | |
1033 | ||
1034 | out_free_pages: | |
c4088ebd | 1035 | spin_unlock(ptl); |
2ec74c3e | 1036 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1037 | mem_cgroup_uncharge_start(); |
1038 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1039 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1040 | put_page(pages[i]); |
b9bbfbe3 AA |
1041 | } |
1042 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1043 | kfree(pages); |
1044 | goto out; | |
1045 | } | |
1046 | ||
1047 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1048 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1049 | { | |
c4088ebd | 1050 | spinlock_t *ptl; |
71e3aac0 | 1051 | int ret = 0; |
93b4796d | 1052 | struct page *page = NULL, *new_page; |
71e3aac0 | 1053 | unsigned long haddr; |
2ec74c3e SG |
1054 | unsigned long mmun_start; /* For mmu_notifiers */ |
1055 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 | 1056 | |
c4088ebd | 1057 | ptl = pmd_lockptr(mm, pmd); |
71e3aac0 | 1058 | VM_BUG_ON(!vma->anon_vma); |
93b4796d KS |
1059 | haddr = address & HPAGE_PMD_MASK; |
1060 | if (is_huge_zero_pmd(orig_pmd)) | |
1061 | goto alloc; | |
c4088ebd | 1062 | spin_lock(ptl); |
71e3aac0 AA |
1063 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
1064 | goto out_unlock; | |
1065 | ||
1066 | page = pmd_page(orig_pmd); | |
309381fe | 1067 | VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page); |
71e3aac0 AA |
1068 | if (page_mapcount(page) == 1) { |
1069 | pmd_t entry; | |
1070 | entry = pmd_mkyoung(orig_pmd); | |
1071 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1072 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1073 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1074 | ret |= VM_FAULT_WRITE; |
1075 | goto out_unlock; | |
1076 | } | |
1077 | get_page(page); | |
c4088ebd | 1078 | spin_unlock(ptl); |
93b4796d | 1079 | alloc: |
71e3aac0 AA |
1080 | if (transparent_hugepage_enabled(vma) && |
1081 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1082 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1083 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1084 | else |
1085 | new_page = NULL; | |
1086 | ||
1087 | if (unlikely(!new_page)) { | |
eecc1e42 | 1088 | if (!page) { |
e9b71ca9 KS |
1089 | split_huge_page_pmd(vma, address, pmd); |
1090 | ret |= VM_FAULT_FALLBACK; | |
93b4796d KS |
1091 | } else { |
1092 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1093 | pmd, orig_pmd, page, haddr); | |
9845cbbd | 1094 | if (ret & VM_FAULT_OOM) { |
93b4796d | 1095 | split_huge_page(page); |
9845cbbd KS |
1096 | ret |= VM_FAULT_FALLBACK; |
1097 | } | |
93b4796d KS |
1098 | put_page(page); |
1099 | } | |
17766dde | 1100 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1101 | goto out; |
1102 | } | |
1103 | ||
b9bbfbe3 AA |
1104 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1105 | put_page(new_page); | |
93b4796d KS |
1106 | if (page) { |
1107 | split_huge_page(page); | |
1108 | put_page(page); | |
9845cbbd KS |
1109 | } else |
1110 | split_huge_page_pmd(vma, address, pmd); | |
1111 | ret |= VM_FAULT_FALLBACK; | |
17766dde | 1112 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1113 | goto out; |
1114 | } | |
1115 | ||
17766dde DR |
1116 | count_vm_event(THP_FAULT_ALLOC); |
1117 | ||
eecc1e42 | 1118 | if (!page) |
93b4796d KS |
1119 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); |
1120 | else | |
1121 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1122 | __SetPageUptodate(new_page); |
1123 | ||
2ec74c3e SG |
1124 | mmun_start = haddr; |
1125 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1126 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1127 | ||
c4088ebd | 1128 | spin_lock(ptl); |
93b4796d KS |
1129 | if (page) |
1130 | put_page(page); | |
b9bbfbe3 | 1131 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
c4088ebd | 1132 | spin_unlock(ptl); |
b9bbfbe3 | 1133 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1134 | put_page(new_page); |
2ec74c3e | 1135 | goto out_mn; |
b9bbfbe3 | 1136 | } else { |
71e3aac0 | 1137 | pmd_t entry; |
3122359a KS |
1138 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1139 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
2ec74c3e | 1140 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1141 | page_add_new_anon_rmap(new_page, vma, haddr); |
1142 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1143 | update_mmu_cache_pmd(vma, address, pmd); |
eecc1e42 | 1144 | if (!page) { |
93b4796d | 1145 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 KS |
1146 | put_huge_zero_page(); |
1147 | } else { | |
309381fe | 1148 | VM_BUG_ON_PAGE(!PageHead(page), page); |
93b4796d KS |
1149 | page_remove_rmap(page); |
1150 | put_page(page); | |
1151 | } | |
71e3aac0 AA |
1152 | ret |= VM_FAULT_WRITE; |
1153 | } | |
c4088ebd | 1154 | spin_unlock(ptl); |
2ec74c3e SG |
1155 | out_mn: |
1156 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1157 | out: |
1158 | return ret; | |
2ec74c3e | 1159 | out_unlock: |
c4088ebd | 1160 | spin_unlock(ptl); |
2ec74c3e | 1161 | return ret; |
71e3aac0 AA |
1162 | } |
1163 | ||
b676b293 | 1164 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1165 | unsigned long addr, |
1166 | pmd_t *pmd, | |
1167 | unsigned int flags) | |
1168 | { | |
b676b293 | 1169 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1170 | struct page *page = NULL; |
1171 | ||
c4088ebd | 1172 | assert_spin_locked(pmd_lockptr(mm, pmd)); |
71e3aac0 AA |
1173 | |
1174 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1175 | goto out; | |
1176 | ||
85facf25 KS |
1177 | /* Avoid dumping huge zero page */ |
1178 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1179 | return ERR_PTR(-EFAULT); | |
1180 | ||
2b4847e7 MG |
1181 | /* Full NUMA hinting faults to serialise migration in fault paths */ |
1182 | if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) | |
1183 | goto out; | |
1184 | ||
71e3aac0 | 1185 | page = pmd_page(*pmd); |
309381fe | 1186 | VM_BUG_ON_PAGE(!PageHead(page), page); |
71e3aac0 AA |
1187 | if (flags & FOLL_TOUCH) { |
1188 | pmd_t _pmd; | |
1189 | /* | |
1190 | * We should set the dirty bit only for FOLL_WRITE but | |
1191 | * for now the dirty bit in the pmd is meaningless. | |
1192 | * And if the dirty bit will become meaningful and | |
1193 | * we'll only set it with FOLL_WRITE, an atomic | |
1194 | * set_bit will be required on the pmd to set the | |
1195 | * young bit, instead of the current set_pmd_at. | |
1196 | */ | |
1197 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
8663890a AK |
1198 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
1199 | pmd, _pmd, 1)) | |
1200 | update_mmu_cache_pmd(vma, addr, pmd); | |
71e3aac0 | 1201 | } |
b676b293 DR |
1202 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1203 | if (page->mapping && trylock_page(page)) { | |
1204 | lru_add_drain(); | |
1205 | if (page->mapping) | |
1206 | mlock_vma_page(page); | |
1207 | unlock_page(page); | |
1208 | } | |
1209 | } | |
71e3aac0 | 1210 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
309381fe | 1211 | VM_BUG_ON_PAGE(!PageCompound(page), page); |
71e3aac0 | 1212 | if (flags & FOLL_GET) |
70b50f94 | 1213 | get_page_foll(page); |
71e3aac0 AA |
1214 | |
1215 | out: | |
1216 | return page; | |
1217 | } | |
1218 | ||
d10e63f2 | 1219 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1220 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1221 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1222 | { |
c4088ebd | 1223 | spinlock_t *ptl; |
b8916634 | 1224 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1225 | struct page *page; |
d10e63f2 | 1226 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
8191acbd | 1227 | int page_nid = -1, this_nid = numa_node_id(); |
90572890 | 1228 | int target_nid, last_cpupid = -1; |
8191acbd MG |
1229 | bool page_locked; |
1230 | bool migrated = false; | |
6688cc05 | 1231 | int flags = 0; |
d10e63f2 | 1232 | |
c4088ebd | 1233 | ptl = pmd_lock(mm, pmdp); |
d10e63f2 MG |
1234 | if (unlikely(!pmd_same(pmd, *pmdp))) |
1235 | goto out_unlock; | |
1236 | ||
de466bd6 MG |
1237 | /* |
1238 | * If there are potential migrations, wait for completion and retry | |
1239 | * without disrupting NUMA hinting information. Do not relock and | |
1240 | * check_same as the page may no longer be mapped. | |
1241 | */ | |
1242 | if (unlikely(pmd_trans_migrating(*pmdp))) { | |
1243 | spin_unlock(ptl); | |
1244 | wait_migrate_huge_page(vma->anon_vma, pmdp); | |
1245 | goto out; | |
1246 | } | |
1247 | ||
d10e63f2 | 1248 | page = pmd_page(pmd); |
a1a46184 | 1249 | BUG_ON(is_huge_zero_page(page)); |
8191acbd | 1250 | page_nid = page_to_nid(page); |
90572890 | 1251 | last_cpupid = page_cpupid_last(page); |
03c5a6e1 | 1252 | count_vm_numa_event(NUMA_HINT_FAULTS); |
04bb2f94 | 1253 | if (page_nid == this_nid) { |
03c5a6e1 | 1254 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
1255 | flags |= TNF_FAULT_LOCAL; |
1256 | } | |
4daae3b4 | 1257 | |
6688cc05 PZ |
1258 | /* |
1259 | * Avoid grouping on DSO/COW pages in specific and RO pages | |
1260 | * in general, RO pages shouldn't hurt as much anyway since | |
1261 | * they can be in shared cache state. | |
1262 | */ | |
1263 | if (!pmd_write(pmd)) | |
1264 | flags |= TNF_NO_GROUP; | |
1265 | ||
ff9042b1 MG |
1266 | /* |
1267 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1268 | * page_table_lock if at all possible | |
1269 | */ | |
b8916634 MG |
1270 | page_locked = trylock_page(page); |
1271 | target_nid = mpol_misplaced(page, vma, haddr); | |
1272 | if (target_nid == -1) { | |
1273 | /* If the page was locked, there are no parallel migrations */ | |
a54a407f | 1274 | if (page_locked) |
b8916634 | 1275 | goto clear_pmdnuma; |
2b4847e7 | 1276 | } |
4daae3b4 | 1277 | |
de466bd6 | 1278 | /* Migration could have started since the pmd_trans_migrating check */ |
2b4847e7 | 1279 | if (!page_locked) { |
c4088ebd | 1280 | spin_unlock(ptl); |
b8916634 | 1281 | wait_on_page_locked(page); |
a54a407f | 1282 | page_nid = -1; |
b8916634 MG |
1283 | goto out; |
1284 | } | |
1285 | ||
2b4847e7 MG |
1286 | /* |
1287 | * Page is misplaced. Page lock serialises migrations. Acquire anon_vma | |
1288 | * to serialises splits | |
1289 | */ | |
b8916634 | 1290 | get_page(page); |
c4088ebd | 1291 | spin_unlock(ptl); |
b8916634 | 1292 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1293 | |
c69307d5 | 1294 | /* Confirm the PMD did not change while page_table_lock was released */ |
c4088ebd | 1295 | spin_lock(ptl); |
b32967ff MG |
1296 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1297 | unlock_page(page); | |
1298 | put_page(page); | |
a54a407f | 1299 | page_nid = -1; |
4daae3b4 | 1300 | goto out_unlock; |
b32967ff | 1301 | } |
ff9042b1 | 1302 | |
c3a489ca MG |
1303 | /* Bail if we fail to protect against THP splits for any reason */ |
1304 | if (unlikely(!anon_vma)) { | |
1305 | put_page(page); | |
1306 | page_nid = -1; | |
1307 | goto clear_pmdnuma; | |
1308 | } | |
1309 | ||
a54a407f MG |
1310 | /* |
1311 | * Migrate the THP to the requested node, returns with page unlocked | |
1312 | * and pmd_numa cleared. | |
1313 | */ | |
c4088ebd | 1314 | spin_unlock(ptl); |
b32967ff | 1315 | migrated = migrate_misplaced_transhuge_page(mm, vma, |
340ef390 | 1316 | pmdp, pmd, addr, page, target_nid); |
6688cc05 PZ |
1317 | if (migrated) { |
1318 | flags |= TNF_MIGRATED; | |
8191acbd | 1319 | page_nid = target_nid; |
6688cc05 | 1320 | } |
b32967ff | 1321 | |
8191acbd | 1322 | goto out; |
b32967ff | 1323 | clear_pmdnuma: |
a54a407f | 1324 | BUG_ON(!PageLocked(page)); |
d10e63f2 MG |
1325 | pmd = pmd_mknonnuma(pmd); |
1326 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1327 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1328 | update_mmu_cache_pmd(vma, addr, pmdp); | |
a54a407f | 1329 | unlock_page(page); |
d10e63f2 | 1330 | out_unlock: |
c4088ebd | 1331 | spin_unlock(ptl); |
b8916634 MG |
1332 | |
1333 | out: | |
1334 | if (anon_vma) | |
1335 | page_unlock_anon_vma_read(anon_vma); | |
1336 | ||
8191acbd | 1337 | if (page_nid != -1) |
6688cc05 | 1338 | task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags); |
8191acbd | 1339 | |
d10e63f2 MG |
1340 | return 0; |
1341 | } | |
1342 | ||
71e3aac0 | 1343 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1344 | pmd_t *pmd, unsigned long addr) |
71e3aac0 | 1345 | { |
bf929152 | 1346 | spinlock_t *ptl; |
71e3aac0 AA |
1347 | int ret = 0; |
1348 | ||
bf929152 | 1349 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 NH |
1350 | struct page *page; |
1351 | pgtable_t pgtable; | |
f5c8ad47 | 1352 | pmd_t orig_pmd; |
a6bf2bb0 AK |
1353 | /* |
1354 | * For architectures like ppc64 we look at deposited pgtable | |
1355 | * when calling pmdp_get_and_clear. So do the | |
1356 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1357 | * operations. | |
1358 | */ | |
f5c8ad47 | 1359 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1360 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
a6bf2bb0 | 1361 | pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); |
479f0abb | 1362 | if (is_huge_zero_pmd(orig_pmd)) { |
e1f56c89 | 1363 | atomic_long_dec(&tlb->mm->nr_ptes); |
bf929152 | 1364 | spin_unlock(ptl); |
97ae1749 | 1365 | put_huge_zero_page(); |
479f0abb KS |
1366 | } else { |
1367 | page = pmd_page(orig_pmd); | |
1368 | page_remove_rmap(page); | |
309381fe | 1369 | VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); |
479f0abb | 1370 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); |
309381fe | 1371 | VM_BUG_ON_PAGE(!PageHead(page), page); |
e1f56c89 | 1372 | atomic_long_dec(&tlb->mm->nr_ptes); |
bf929152 | 1373 | spin_unlock(ptl); |
479f0abb KS |
1374 | tlb_remove_page(tlb, page); |
1375 | } | |
025c5b24 NH |
1376 | pte_free(tlb->mm, pgtable); |
1377 | ret = 1; | |
1378 | } | |
71e3aac0 AA |
1379 | return ret; |
1380 | } | |
1381 | ||
0ca1634d JW |
1382 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1383 | unsigned long addr, unsigned long end, | |
1384 | unsigned char *vec) | |
1385 | { | |
bf929152 | 1386 | spinlock_t *ptl; |
0ca1634d JW |
1387 | int ret = 0; |
1388 | ||
bf929152 | 1389 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 NH |
1390 | /* |
1391 | * All logical pages in the range are present | |
1392 | * if backed by a huge page. | |
1393 | */ | |
bf929152 | 1394 | spin_unlock(ptl); |
025c5b24 NH |
1395 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1396 | ret = 1; | |
1397 | } | |
0ca1634d JW |
1398 | |
1399 | return ret; | |
1400 | } | |
1401 | ||
37a1c49a AA |
1402 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1403 | unsigned long old_addr, | |
1404 | unsigned long new_addr, unsigned long old_end, | |
1405 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1406 | { | |
bf929152 | 1407 | spinlock_t *old_ptl, *new_ptl; |
37a1c49a AA |
1408 | int ret = 0; |
1409 | pmd_t pmd; | |
1410 | ||
1411 | struct mm_struct *mm = vma->vm_mm; | |
1412 | ||
1413 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1414 | (new_addr & ~HPAGE_PMD_MASK) || | |
1415 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1416 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1417 | goto out; | |
1418 | ||
1419 | /* | |
1420 | * The destination pmd shouldn't be established, free_pgtables() | |
1421 | * should have release it. | |
1422 | */ | |
1423 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1424 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1425 | goto out; | |
1426 | } | |
1427 | ||
bf929152 KS |
1428 | /* |
1429 | * We don't have to worry about the ordering of src and dst | |
1430 | * ptlocks because exclusive mmap_sem prevents deadlock. | |
1431 | */ | |
1432 | ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl); | |
025c5b24 | 1433 | if (ret == 1) { |
bf929152 KS |
1434 | new_ptl = pmd_lockptr(mm, new_pmd); |
1435 | if (new_ptl != old_ptl) | |
1436 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); | |
025c5b24 NH |
1437 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); |
1438 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
3592806c | 1439 | |
b3084f4d AK |
1440 | if (pmd_move_must_withdraw(new_ptl, old_ptl)) { |
1441 | pgtable_t pgtable; | |
3592806c KS |
1442 | pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); |
1443 | pgtable_trans_huge_deposit(mm, new_pmd, pgtable); | |
3592806c | 1444 | } |
b3084f4d AK |
1445 | set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); |
1446 | if (new_ptl != old_ptl) | |
1447 | spin_unlock(new_ptl); | |
bf929152 | 1448 | spin_unlock(old_ptl); |
37a1c49a AA |
1449 | } |
1450 | out: | |
1451 | return ret; | |
1452 | } | |
1453 | ||
f123d74a MG |
1454 | /* |
1455 | * Returns | |
1456 | * - 0 if PMD could not be locked | |
1457 | * - 1 if PMD was locked but protections unchange and TLB flush unnecessary | |
1458 | * - HPAGE_PMD_NR is protections changed and TLB flush necessary | |
1459 | */ | |
cd7548ab | 1460 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1461 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1462 | { |
1463 | struct mm_struct *mm = vma->vm_mm; | |
bf929152 | 1464 | spinlock_t *ptl; |
cd7548ab JW |
1465 | int ret = 0; |
1466 | ||
bf929152 | 1467 | if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { |
025c5b24 | 1468 | pmd_t entry; |
f123d74a | 1469 | ret = 1; |
a4f1de17 | 1470 | if (!prot_numa) { |
f123d74a | 1471 | entry = pmdp_get_and_clear(mm, addr, pmd); |
1667918b MG |
1472 | if (pmd_numa(entry)) |
1473 | entry = pmd_mknonnuma(entry); | |
4b10e7d5 | 1474 | entry = pmd_modify(entry, newprot); |
f123d74a | 1475 | ret = HPAGE_PMD_NR; |
56eecdb9 | 1476 | set_pmd_at(mm, addr, pmd, entry); |
a4f1de17 HD |
1477 | BUG_ON(pmd_write(entry)); |
1478 | } else { | |
4b10e7d5 MG |
1479 | struct page *page = pmd_page(*pmd); |
1480 | ||
a1a46184 | 1481 | /* |
1bc115d8 MG |
1482 | * Do not trap faults against the zero page. The |
1483 | * read-only data is likely to be read-cached on the | |
1484 | * local CPU cache and it is less useful to know about | |
1485 | * local vs remote hits on the zero page. | |
a1a46184 | 1486 | */ |
1bc115d8 | 1487 | if (!is_huge_zero_page(page) && |
4b10e7d5 | 1488 | !pmd_numa(*pmd)) { |
56eecdb9 | 1489 | pmdp_set_numa(mm, addr, pmd); |
f123d74a | 1490 | ret = HPAGE_PMD_NR; |
4b10e7d5 MG |
1491 | } |
1492 | } | |
bf929152 | 1493 | spin_unlock(ptl); |
025c5b24 NH |
1494 | } |
1495 | ||
1496 | return ret; | |
1497 | } | |
1498 | ||
1499 | /* | |
1500 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1501 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1502 | * | |
1503 | * Note that if it returns 1, this routine returns without unlocking page | |
1504 | * table locks. So callers must unlock them. | |
1505 | */ | |
bf929152 KS |
1506 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, |
1507 | spinlock_t **ptl) | |
025c5b24 | 1508 | { |
bf929152 | 1509 | *ptl = pmd_lock(vma->vm_mm, pmd); |
cd7548ab JW |
1510 | if (likely(pmd_trans_huge(*pmd))) { |
1511 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
bf929152 | 1512 | spin_unlock(*ptl); |
cd7548ab | 1513 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1514 | return -1; |
cd7548ab | 1515 | } else { |
025c5b24 NH |
1516 | /* Thp mapped by 'pmd' is stable, so we can |
1517 | * handle it as it is. */ | |
1518 | return 1; | |
cd7548ab | 1519 | } |
025c5b24 | 1520 | } |
bf929152 | 1521 | spin_unlock(*ptl); |
025c5b24 | 1522 | return 0; |
cd7548ab JW |
1523 | } |
1524 | ||
117b0791 KS |
1525 | /* |
1526 | * This function returns whether a given @page is mapped onto the @address | |
1527 | * in the virtual space of @mm. | |
1528 | * | |
1529 | * When it's true, this function returns *pmd with holding the page table lock | |
1530 | * and passing it back to the caller via @ptl. | |
1531 | * If it's false, returns NULL without holding the page table lock. | |
1532 | */ | |
71e3aac0 AA |
1533 | pmd_t *page_check_address_pmd(struct page *page, |
1534 | struct mm_struct *mm, | |
1535 | unsigned long address, | |
117b0791 KS |
1536 | enum page_check_address_pmd_flag flag, |
1537 | spinlock_t **ptl) | |
71e3aac0 | 1538 | { |
117b0791 | 1539 | pmd_t *pmd; |
71e3aac0 AA |
1540 | |
1541 | if (address & ~HPAGE_PMD_MASK) | |
117b0791 | 1542 | return NULL; |
71e3aac0 | 1543 | |
6219049a BL |
1544 | pmd = mm_find_pmd(mm, address); |
1545 | if (!pmd) | |
117b0791 KS |
1546 | return NULL; |
1547 | *ptl = pmd_lock(mm, pmd); | |
71e3aac0 | 1548 | if (pmd_none(*pmd)) |
117b0791 | 1549 | goto unlock; |
71e3aac0 | 1550 | if (pmd_page(*pmd) != page) |
117b0791 | 1551 | goto unlock; |
94fcc585 AA |
1552 | /* |
1553 | * split_vma() may create temporary aliased mappings. There is | |
1554 | * no risk as long as all huge pmd are found and have their | |
1555 | * splitting bit set before __split_huge_page_refcount | |
1556 | * runs. Finding the same huge pmd more than once during the | |
1557 | * same rmap walk is not a problem. | |
1558 | */ | |
1559 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1560 | pmd_trans_splitting(*pmd)) | |
117b0791 | 1561 | goto unlock; |
71e3aac0 AA |
1562 | if (pmd_trans_huge(*pmd)) { |
1563 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1564 | !pmd_trans_splitting(*pmd)); | |
117b0791 | 1565 | return pmd; |
71e3aac0 | 1566 | } |
117b0791 KS |
1567 | unlock: |
1568 | spin_unlock(*ptl); | |
1569 | return NULL; | |
71e3aac0 AA |
1570 | } |
1571 | ||
1572 | static int __split_huge_page_splitting(struct page *page, | |
1573 | struct vm_area_struct *vma, | |
1574 | unsigned long address) | |
1575 | { | |
1576 | struct mm_struct *mm = vma->vm_mm; | |
117b0791 | 1577 | spinlock_t *ptl; |
71e3aac0 AA |
1578 | pmd_t *pmd; |
1579 | int ret = 0; | |
2ec74c3e SG |
1580 | /* For mmu_notifiers */ |
1581 | const unsigned long mmun_start = address; | |
1582 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1583 | |
2ec74c3e | 1584 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 | 1585 | pmd = page_check_address_pmd(page, mm, address, |
117b0791 | 1586 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl); |
71e3aac0 AA |
1587 | if (pmd) { |
1588 | /* | |
1589 | * We can't temporarily set the pmd to null in order | |
1590 | * to split it, the pmd must remain marked huge at all | |
1591 | * times or the VM won't take the pmd_trans_huge paths | |
5a505085 | 1592 | * and it won't wait on the anon_vma->root->rwsem to |
71e3aac0 AA |
1593 | * serialize against split_huge_page*. |
1594 | */ | |
2ec74c3e | 1595 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 | 1596 | ret = 1; |
117b0791 | 1597 | spin_unlock(ptl); |
71e3aac0 | 1598 | } |
2ec74c3e | 1599 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1600 | |
1601 | return ret; | |
1602 | } | |
1603 | ||
5bc7b8ac SL |
1604 | static void __split_huge_page_refcount(struct page *page, |
1605 | struct list_head *list) | |
71e3aac0 AA |
1606 | { |
1607 | int i; | |
71e3aac0 | 1608 | struct zone *zone = page_zone(page); |
fa9add64 | 1609 | struct lruvec *lruvec; |
70b50f94 | 1610 | int tail_count = 0; |
71e3aac0 AA |
1611 | |
1612 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1613 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1614 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1615 | ||
71e3aac0 | 1616 | compound_lock(page); |
e94c8a9c KH |
1617 | /* complete memcg works before add pages to LRU */ |
1618 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1619 | |
45676885 | 1620 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1621 | struct page *page_tail = page + i; |
1622 | ||
70b50f94 AA |
1623 | /* tail_page->_mapcount cannot change */ |
1624 | BUG_ON(page_mapcount(page_tail) < 0); | |
1625 | tail_count += page_mapcount(page_tail); | |
1626 | /* check for overflow */ | |
1627 | BUG_ON(tail_count < 0); | |
1628 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1629 | /* | |
1630 | * tail_page->_count is zero and not changing from | |
1631 | * under us. But get_page_unless_zero() may be running | |
1632 | * from under us on the tail_page. If we used | |
1633 | * atomic_set() below instead of atomic_add(), we | |
1634 | * would then run atomic_set() concurrently with | |
1635 | * get_page_unless_zero(), and atomic_set() is | |
1636 | * implemented in C not using locked ops. spin_unlock | |
1637 | * on x86 sometime uses locked ops because of PPro | |
1638 | * errata 66, 92, so unless somebody can guarantee | |
1639 | * atomic_set() here would be safe on all archs (and | |
1640 | * not only on x86), it's safer to use atomic_add(). | |
1641 | */ | |
1642 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1643 | &page_tail->_count); | |
71e3aac0 AA |
1644 | |
1645 | /* after clearing PageTail the gup refcount can be released */ | |
1646 | smp_mb(); | |
1647 | ||
a6d30ddd JD |
1648 | /* |
1649 | * retain hwpoison flag of the poisoned tail page: | |
1650 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1651 | * by the memory-failure. | |
1652 | */ | |
1653 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1654 | page_tail->flags |= (page->flags & |
1655 | ((1L << PG_referenced) | | |
1656 | (1L << PG_swapbacked) | | |
1657 | (1L << PG_mlocked) | | |
e180cf80 KS |
1658 | (1L << PG_uptodate) | |
1659 | (1L << PG_active) | | |
1660 | (1L << PG_unevictable))); | |
71e3aac0 AA |
1661 | page_tail->flags |= (1L << PG_dirty); |
1662 | ||
70b50f94 | 1663 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1664 | smp_wmb(); |
1665 | ||
1666 | /* | |
1667 | * __split_huge_page_splitting() already set the | |
1668 | * splitting bit in all pmd that could map this | |
1669 | * hugepage, that will ensure no CPU can alter the | |
1670 | * mapcount on the head page. The mapcount is only | |
1671 | * accounted in the head page and it has to be | |
1672 | * transferred to all tail pages in the below code. So | |
1673 | * for this code to be safe, the split the mapcount | |
1674 | * can't change. But that doesn't mean userland can't | |
1675 | * keep changing and reading the page contents while | |
1676 | * we transfer the mapcount, so the pmd splitting | |
1677 | * status is achieved setting a reserved bit in the | |
1678 | * pmd, not by clearing the present bit. | |
1679 | */ | |
71e3aac0 AA |
1680 | page_tail->_mapcount = page->_mapcount; |
1681 | ||
1682 | BUG_ON(page_tail->mapping); | |
1683 | page_tail->mapping = page->mapping; | |
1684 | ||
45676885 | 1685 | page_tail->index = page->index + i; |
90572890 | 1686 | page_cpupid_xchg_last(page_tail, page_cpupid_last(page)); |
71e3aac0 AA |
1687 | |
1688 | BUG_ON(!PageAnon(page_tail)); | |
1689 | BUG_ON(!PageUptodate(page_tail)); | |
1690 | BUG_ON(!PageDirty(page_tail)); | |
1691 | BUG_ON(!PageSwapBacked(page_tail)); | |
1692 | ||
5bc7b8ac | 1693 | lru_add_page_tail(page, page_tail, lruvec, list); |
71e3aac0 | 1694 | } |
70b50f94 AA |
1695 | atomic_sub(tail_count, &page->_count); |
1696 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1697 | |
fa9add64 | 1698 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 | 1699 | |
71e3aac0 AA |
1700 | ClearPageCompound(page); |
1701 | compound_unlock(page); | |
1702 | spin_unlock_irq(&zone->lru_lock); | |
1703 | ||
1704 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1705 | struct page *page_tail = page + i; | |
1706 | BUG_ON(page_count(page_tail) <= 0); | |
1707 | /* | |
1708 | * Tail pages may be freed if there wasn't any mapping | |
1709 | * like if add_to_swap() is running on a lru page that | |
1710 | * had its mapping zapped. And freeing these pages | |
1711 | * requires taking the lru_lock so we do the put_page | |
1712 | * of the tail pages after the split is complete. | |
1713 | */ | |
1714 | put_page(page_tail); | |
1715 | } | |
1716 | ||
1717 | /* | |
1718 | * Only the head page (now become a regular page) is required | |
1719 | * to be pinned by the caller. | |
1720 | */ | |
1721 | BUG_ON(page_count(page) <= 0); | |
1722 | } | |
1723 | ||
1724 | static int __split_huge_page_map(struct page *page, | |
1725 | struct vm_area_struct *vma, | |
1726 | unsigned long address) | |
1727 | { | |
1728 | struct mm_struct *mm = vma->vm_mm; | |
117b0791 | 1729 | spinlock_t *ptl; |
71e3aac0 AA |
1730 | pmd_t *pmd, _pmd; |
1731 | int ret = 0, i; | |
1732 | pgtable_t pgtable; | |
1733 | unsigned long haddr; | |
1734 | ||
71e3aac0 | 1735 | pmd = page_check_address_pmd(page, mm, address, |
117b0791 | 1736 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl); |
71e3aac0 | 1737 | if (pmd) { |
6b0b50b0 | 1738 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1739 | pmd_populate(mm, &_pmd, pgtable); |
1740 | ||
e3ebcf64 GS |
1741 | haddr = address; |
1742 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1743 | pte_t *pte, entry; |
1744 | BUG_ON(PageCompound(page+i)); | |
1745 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1746 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1747 | if (!pmd_write(*pmd)) | |
1748 | entry = pte_wrprotect(entry); | |
1749 | else | |
1750 | BUG_ON(page_mapcount(page) != 1); | |
1751 | if (!pmd_young(*pmd)) | |
1752 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1753 | if (pmd_numa(*pmd)) |
1754 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1755 | pte = pte_offset_map(&_pmd, haddr); |
1756 | BUG_ON(!pte_none(*pte)); | |
1757 | set_pte_at(mm, haddr, pte, entry); | |
1758 | pte_unmap(pte); | |
1759 | } | |
1760 | ||
71e3aac0 AA |
1761 | smp_wmb(); /* make pte visible before pmd */ |
1762 | /* | |
1763 | * Up to this point the pmd is present and huge and | |
1764 | * userland has the whole access to the hugepage | |
1765 | * during the split (which happens in place). If we | |
1766 | * overwrite the pmd with the not-huge version | |
1767 | * pointing to the pte here (which of course we could | |
1768 | * if all CPUs were bug free), userland could trigger | |
1769 | * a small page size TLB miss on the small sized TLB | |
1770 | * while the hugepage TLB entry is still established | |
1771 | * in the huge TLB. Some CPU doesn't like that. See | |
1772 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1773 | * Erratum 383 on page 93. Intel should be safe but is | |
1774 | * also warns that it's only safe if the permission | |
1775 | * and cache attributes of the two entries loaded in | |
1776 | * the two TLB is identical (which should be the case | |
1777 | * here). But it is generally safer to never allow | |
1778 | * small and huge TLB entries for the same virtual | |
1779 | * address to be loaded simultaneously. So instead of | |
1780 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1781 | * mark the current pmd notpresent (atomically because | |
1782 | * here the pmd_trans_huge and pmd_trans_splitting | |
1783 | * must remain set at all times on the pmd until the | |
1784 | * split is complete for this pmd), then we flush the | |
1785 | * SMP TLB and finally we write the non-huge version | |
1786 | * of the pmd entry with pmd_populate. | |
1787 | */ | |
46dcde73 | 1788 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1789 | pmd_populate(mm, pmd, pgtable); |
1790 | ret = 1; | |
117b0791 | 1791 | spin_unlock(ptl); |
71e3aac0 | 1792 | } |
71e3aac0 AA |
1793 | |
1794 | return ret; | |
1795 | } | |
1796 | ||
5a505085 | 1797 | /* must be called with anon_vma->root->rwsem held */ |
71e3aac0 | 1798 | static void __split_huge_page(struct page *page, |
5bc7b8ac SL |
1799 | struct anon_vma *anon_vma, |
1800 | struct list_head *list) | |
71e3aac0 AA |
1801 | { |
1802 | int mapcount, mapcount2; | |
bf181b9f | 1803 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1804 | struct anon_vma_chain *avc; |
1805 | ||
1806 | BUG_ON(!PageHead(page)); | |
1807 | BUG_ON(PageTail(page)); | |
1808 | ||
1809 | mapcount = 0; | |
bf181b9f | 1810 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1811 | struct vm_area_struct *vma = avc->vma; |
1812 | unsigned long addr = vma_address(page, vma); | |
1813 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1814 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1815 | } | |
05759d38 AA |
1816 | /* |
1817 | * It is critical that new vmas are added to the tail of the | |
1818 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1819 | * and establishes a child pmd before | |
1820 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1821 | * we fail to prevent copy_huge_pmd() from running until the | |
1822 | * whole __split_huge_page() is complete), we will still see | |
1823 | * the newly established pmd of the child later during the | |
1824 | * walk, to be able to set it as pmd_trans_splitting too. | |
1825 | */ | |
1826 | if (mapcount != page_mapcount(page)) | |
1827 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1828 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1829 | BUG_ON(mapcount != page_mapcount(page)); |
1830 | ||
5bc7b8ac | 1831 | __split_huge_page_refcount(page, list); |
71e3aac0 AA |
1832 | |
1833 | mapcount2 = 0; | |
bf181b9f | 1834 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1835 | struct vm_area_struct *vma = avc->vma; |
1836 | unsigned long addr = vma_address(page, vma); | |
1837 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1838 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1839 | } | |
05759d38 AA |
1840 | if (mapcount != mapcount2) |
1841 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1842 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1843 | BUG_ON(mapcount != mapcount2); |
1844 | } | |
1845 | ||
5bc7b8ac SL |
1846 | /* |
1847 | * Split a hugepage into normal pages. This doesn't change the position of head | |
1848 | * page. If @list is null, tail pages will be added to LRU list, otherwise, to | |
1849 | * @list. Both head page and tail pages will inherit mapping, flags, and so on | |
1850 | * from the hugepage. | |
1851 | * Return 0 if the hugepage is split successfully otherwise return 1. | |
1852 | */ | |
1853 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
71e3aac0 AA |
1854 | { |
1855 | struct anon_vma *anon_vma; | |
1856 | int ret = 1; | |
1857 | ||
5918d10a | 1858 | BUG_ON(is_huge_zero_page(page)); |
71e3aac0 | 1859 | BUG_ON(!PageAnon(page)); |
062f1af2 MG |
1860 | |
1861 | /* | |
1862 | * The caller does not necessarily hold an mmap_sem that would prevent | |
1863 | * the anon_vma disappearing so we first we take a reference to it | |
1864 | * and then lock the anon_vma for write. This is similar to | |
1865 | * page_lock_anon_vma_read except the write lock is taken to serialise | |
1866 | * against parallel split or collapse operations. | |
1867 | */ | |
1868 | anon_vma = page_get_anon_vma(page); | |
71e3aac0 AA |
1869 | if (!anon_vma) |
1870 | goto out; | |
062f1af2 MG |
1871 | anon_vma_lock_write(anon_vma); |
1872 | ||
71e3aac0 AA |
1873 | ret = 0; |
1874 | if (!PageCompound(page)) | |
1875 | goto out_unlock; | |
1876 | ||
1877 | BUG_ON(!PageSwapBacked(page)); | |
5bc7b8ac | 1878 | __split_huge_page(page, anon_vma, list); |
81ab4201 | 1879 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1880 | |
1881 | BUG_ON(PageCompound(page)); | |
1882 | out_unlock: | |
08b52706 | 1883 | anon_vma_unlock_write(anon_vma); |
062f1af2 | 1884 | put_anon_vma(anon_vma); |
71e3aac0 AA |
1885 | out: |
1886 | return ret; | |
1887 | } | |
1888 | ||
9050d7eb | 1889 | #define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE) |
78f11a25 | 1890 | |
60ab3244 AA |
1891 | int hugepage_madvise(struct vm_area_struct *vma, |
1892 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1893 | { |
8e72033f GS |
1894 | struct mm_struct *mm = vma->vm_mm; |
1895 | ||
a664b2d8 AA |
1896 | switch (advice) { |
1897 | case MADV_HUGEPAGE: | |
1898 | /* | |
1899 | * Be somewhat over-protective like KSM for now! | |
1900 | */ | |
78f11a25 | 1901 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1902 | return -EINVAL; |
8e72033f GS |
1903 | if (mm->def_flags & VM_NOHUGEPAGE) |
1904 | return -EINVAL; | |
a664b2d8 AA |
1905 | *vm_flags &= ~VM_NOHUGEPAGE; |
1906 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1907 | /* |
1908 | * If the vma become good for khugepaged to scan, | |
1909 | * register it here without waiting a page fault that | |
1910 | * may not happen any time soon. | |
1911 | */ | |
1912 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1913 | return -ENOMEM; | |
a664b2d8 AA |
1914 | break; |
1915 | case MADV_NOHUGEPAGE: | |
1916 | /* | |
1917 | * Be somewhat over-protective like KSM for now! | |
1918 | */ | |
78f11a25 | 1919 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1920 | return -EINVAL; |
1921 | *vm_flags &= ~VM_HUGEPAGE; | |
1922 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1923 | /* |
1924 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1925 | * this vma even if we leave the mm registered in khugepaged if | |
1926 | * it got registered before VM_NOHUGEPAGE was set. | |
1927 | */ | |
a664b2d8 AA |
1928 | break; |
1929 | } | |
0af4e98b AA |
1930 | |
1931 | return 0; | |
1932 | } | |
1933 | ||
ba76149f AA |
1934 | static int __init khugepaged_slab_init(void) |
1935 | { | |
1936 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1937 | sizeof(struct mm_slot), | |
1938 | __alignof__(struct mm_slot), 0, NULL); | |
1939 | if (!mm_slot_cache) | |
1940 | return -ENOMEM; | |
1941 | ||
1942 | return 0; | |
1943 | } | |
1944 | ||
ba76149f AA |
1945 | static inline struct mm_slot *alloc_mm_slot(void) |
1946 | { | |
1947 | if (!mm_slot_cache) /* initialization failed */ | |
1948 | return NULL; | |
1949 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1950 | } | |
1951 | ||
1952 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1953 | { | |
1954 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1955 | } | |
1956 | ||
ba76149f AA |
1957 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) |
1958 | { | |
1959 | struct mm_slot *mm_slot; | |
ba76149f | 1960 | |
b67bfe0d | 1961 | hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) |
ba76149f AA |
1962 | if (mm == mm_slot->mm) |
1963 | return mm_slot; | |
43b5fbbd | 1964 | |
ba76149f AA |
1965 | return NULL; |
1966 | } | |
1967 | ||
1968 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1969 | struct mm_slot *mm_slot) | |
1970 | { | |
ba76149f | 1971 | mm_slot->mm = mm; |
43b5fbbd | 1972 | hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); |
ba76149f AA |
1973 | } |
1974 | ||
1975 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1976 | { | |
1977 | return atomic_read(&mm->mm_users) == 0; | |
1978 | } | |
1979 | ||
1980 | int __khugepaged_enter(struct mm_struct *mm) | |
1981 | { | |
1982 | struct mm_slot *mm_slot; | |
1983 | int wakeup; | |
1984 | ||
1985 | mm_slot = alloc_mm_slot(); | |
1986 | if (!mm_slot) | |
1987 | return -ENOMEM; | |
1988 | ||
1989 | /* __khugepaged_exit() must not run from under us */ | |
1990 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1991 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1992 | free_mm_slot(mm_slot); | |
1993 | return 0; | |
1994 | } | |
1995 | ||
1996 | spin_lock(&khugepaged_mm_lock); | |
1997 | insert_to_mm_slots_hash(mm, mm_slot); | |
1998 | /* | |
1999 | * Insert just behind the scanning cursor, to let the area settle | |
2000 | * down a little. | |
2001 | */ | |
2002 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
2003 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
2004 | spin_unlock(&khugepaged_mm_lock); | |
2005 | ||
2006 | atomic_inc(&mm->mm_count); | |
2007 | if (wakeup) | |
2008 | wake_up_interruptible(&khugepaged_wait); | |
2009 | ||
2010 | return 0; | |
2011 | } | |
2012 | ||
2013 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
2014 | { | |
2015 | unsigned long hstart, hend; | |
2016 | if (!vma->anon_vma) | |
2017 | /* | |
2018 | * Not yet faulted in so we will register later in the | |
2019 | * page fault if needed. | |
2020 | */ | |
2021 | return 0; | |
78f11a25 | 2022 | if (vma->vm_ops) |
ba76149f AA |
2023 | /* khugepaged not yet working on file or special mappings */ |
2024 | return 0; | |
b3b9c293 | 2025 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2026 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2027 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2028 | if (hstart < hend) | |
2029 | return khugepaged_enter(vma); | |
2030 | return 0; | |
2031 | } | |
2032 | ||
2033 | void __khugepaged_exit(struct mm_struct *mm) | |
2034 | { | |
2035 | struct mm_slot *mm_slot; | |
2036 | int free = 0; | |
2037 | ||
2038 | spin_lock(&khugepaged_mm_lock); | |
2039 | mm_slot = get_mm_slot(mm); | |
2040 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
43b5fbbd | 2041 | hash_del(&mm_slot->hash); |
ba76149f AA |
2042 | list_del(&mm_slot->mm_node); |
2043 | free = 1; | |
2044 | } | |
d788e80a | 2045 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
2046 | |
2047 | if (free) { | |
ba76149f AA |
2048 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
2049 | free_mm_slot(mm_slot); | |
2050 | mmdrop(mm); | |
2051 | } else if (mm_slot) { | |
ba76149f AA |
2052 | /* |
2053 | * This is required to serialize against | |
2054 | * khugepaged_test_exit() (which is guaranteed to run | |
2055 | * under mmap sem read mode). Stop here (after we | |
2056 | * return all pagetables will be destroyed) until | |
2057 | * khugepaged has finished working on the pagetables | |
2058 | * under the mmap_sem. | |
2059 | */ | |
2060 | down_write(&mm->mmap_sem); | |
2061 | up_write(&mm->mmap_sem); | |
d788e80a | 2062 | } |
ba76149f AA |
2063 | } |
2064 | ||
2065 | static void release_pte_page(struct page *page) | |
2066 | { | |
2067 | /* 0 stands for page_is_file_cache(page) == false */ | |
2068 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2069 | unlock_page(page); | |
2070 | putback_lru_page(page); | |
2071 | } | |
2072 | ||
2073 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
2074 | { | |
2075 | while (--_pte >= pte) { | |
2076 | pte_t pteval = *_pte; | |
2077 | if (!pte_none(pteval)) | |
2078 | release_pte_page(pte_page(pteval)); | |
2079 | } | |
2080 | } | |
2081 | ||
ba76149f AA |
2082 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
2083 | unsigned long address, | |
2084 | pte_t *pte) | |
2085 | { | |
2086 | struct page *page; | |
2087 | pte_t *_pte; | |
344aa35c | 2088 | int referenced = 0, none = 0; |
ba76149f AA |
2089 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
2090 | _pte++, address += PAGE_SIZE) { | |
2091 | pte_t pteval = *_pte; | |
2092 | if (pte_none(pteval)) { | |
2093 | if (++none <= khugepaged_max_ptes_none) | |
2094 | continue; | |
344aa35c | 2095 | else |
ba76149f | 2096 | goto out; |
ba76149f | 2097 | } |
344aa35c | 2098 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 2099 | goto out; |
ba76149f | 2100 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 2101 | if (unlikely(!page)) |
ba76149f | 2102 | goto out; |
344aa35c | 2103 | |
309381fe SL |
2104 | VM_BUG_ON_PAGE(PageCompound(page), page); |
2105 | VM_BUG_ON_PAGE(!PageAnon(page), page); | |
2106 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
ba76149f AA |
2107 | |
2108 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 2109 | if (page_count(page) != 1) |
ba76149f | 2110 | goto out; |
ba76149f AA |
2111 | /* |
2112 | * We can do it before isolate_lru_page because the | |
2113 | * page can't be freed from under us. NOTE: PG_lock | |
2114 | * is needed to serialize against split_huge_page | |
2115 | * when invoked from the VM. | |
2116 | */ | |
344aa35c | 2117 | if (!trylock_page(page)) |
ba76149f | 2118 | goto out; |
ba76149f AA |
2119 | /* |
2120 | * Isolate the page to avoid collapsing an hugepage | |
2121 | * currently in use by the VM. | |
2122 | */ | |
2123 | if (isolate_lru_page(page)) { | |
2124 | unlock_page(page); | |
ba76149f AA |
2125 | goto out; |
2126 | } | |
2127 | /* 0 stands for page_is_file_cache(page) == false */ | |
2128 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
309381fe SL |
2129 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
2130 | VM_BUG_ON_PAGE(PageLRU(page), page); | |
ba76149f AA |
2131 | |
2132 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
2133 | if (pte_young(pteval) || PageReferenced(page) || |
2134 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2135 | referenced = 1; |
2136 | } | |
344aa35c BL |
2137 | if (likely(referenced)) |
2138 | return 1; | |
ba76149f | 2139 | out: |
344aa35c BL |
2140 | release_pte_pages(pte, _pte); |
2141 | return 0; | |
ba76149f AA |
2142 | } |
2143 | ||
2144 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
2145 | struct vm_area_struct *vma, | |
2146 | unsigned long address, | |
2147 | spinlock_t *ptl) | |
2148 | { | |
2149 | pte_t *_pte; | |
2150 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
2151 | pte_t pteval = *_pte; | |
2152 | struct page *src_page; | |
2153 | ||
2154 | if (pte_none(pteval)) { | |
2155 | clear_user_highpage(page, address); | |
2156 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
2157 | } else { | |
2158 | src_page = pte_page(pteval); | |
2159 | copy_user_highpage(page, src_page, address, vma); | |
309381fe | 2160 | VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page); |
ba76149f AA |
2161 | release_pte_page(src_page); |
2162 | /* | |
2163 | * ptl mostly unnecessary, but preempt has to | |
2164 | * be disabled to update the per-cpu stats | |
2165 | * inside page_remove_rmap(). | |
2166 | */ | |
2167 | spin_lock(ptl); | |
2168 | /* | |
2169 | * paravirt calls inside pte_clear here are | |
2170 | * superfluous. | |
2171 | */ | |
2172 | pte_clear(vma->vm_mm, address, _pte); | |
2173 | page_remove_rmap(src_page); | |
2174 | spin_unlock(ptl); | |
2175 | free_page_and_swap_cache(src_page); | |
2176 | } | |
2177 | ||
2178 | address += PAGE_SIZE; | |
2179 | page++; | |
2180 | } | |
2181 | } | |
2182 | ||
26234f36 | 2183 | static void khugepaged_alloc_sleep(void) |
ba76149f | 2184 | { |
26234f36 XG |
2185 | wait_event_freezable_timeout(khugepaged_wait, false, |
2186 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
2187 | } | |
ba76149f | 2188 | |
9f1b868a BL |
2189 | static int khugepaged_node_load[MAX_NUMNODES]; |
2190 | ||
26234f36 | 2191 | #ifdef CONFIG_NUMA |
9f1b868a BL |
2192 | static int khugepaged_find_target_node(void) |
2193 | { | |
2194 | static int last_khugepaged_target_node = NUMA_NO_NODE; | |
2195 | int nid, target_node = 0, max_value = 0; | |
2196 | ||
2197 | /* find first node with max normal pages hit */ | |
2198 | for (nid = 0; nid < MAX_NUMNODES; nid++) | |
2199 | if (khugepaged_node_load[nid] > max_value) { | |
2200 | max_value = khugepaged_node_load[nid]; | |
2201 | target_node = nid; | |
2202 | } | |
2203 | ||
2204 | /* do some balance if several nodes have the same hit record */ | |
2205 | if (target_node <= last_khugepaged_target_node) | |
2206 | for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES; | |
2207 | nid++) | |
2208 | if (max_value == khugepaged_node_load[nid]) { | |
2209 | target_node = nid; | |
2210 | break; | |
2211 | } | |
2212 | ||
2213 | last_khugepaged_target_node = target_node; | |
2214 | return target_node; | |
2215 | } | |
2216 | ||
26234f36 XG |
2217 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) |
2218 | { | |
2219 | if (IS_ERR(*hpage)) { | |
2220 | if (!*wait) | |
2221 | return false; | |
2222 | ||
2223 | *wait = false; | |
e3b4126c | 2224 | *hpage = NULL; |
26234f36 XG |
2225 | khugepaged_alloc_sleep(); |
2226 | } else if (*hpage) { | |
2227 | put_page(*hpage); | |
2228 | *hpage = NULL; | |
2229 | } | |
2230 | ||
2231 | return true; | |
2232 | } | |
2233 | ||
2234 | static struct page | |
2235 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2236 | struct vm_area_struct *vma, unsigned long address, | |
2237 | int node) | |
2238 | { | |
309381fe | 2239 | VM_BUG_ON_PAGE(*hpage, *hpage); |
ce83d217 AA |
2240 | /* |
2241 | * Allocate the page while the vma is still valid and under | |
2242 | * the mmap_sem read mode so there is no memory allocation | |
2243 | * later when we take the mmap_sem in write mode. This is more | |
2244 | * friendly behavior (OTOH it may actually hide bugs) to | |
2245 | * filesystems in userland with daemons allocating memory in | |
2246 | * the userland I/O paths. Allocating memory with the | |
2247 | * mmap_sem in read mode is good idea also to allow greater | |
2248 | * scalability. | |
2249 | */ | |
9f1b868a BL |
2250 | *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask( |
2251 | khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER); | |
692e0b35 AA |
2252 | /* |
2253 | * After allocating the hugepage, release the mmap_sem read lock in | |
2254 | * preparation for taking it in write mode. | |
2255 | */ | |
2256 | up_read(&mm->mmap_sem); | |
26234f36 | 2257 | if (unlikely(!*hpage)) { |
81ab4201 | 2258 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2259 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2260 | return NULL; |
ce83d217 | 2261 | } |
26234f36 | 2262 | |
65b3c07b | 2263 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2264 | return *hpage; |
2265 | } | |
2266 | #else | |
9f1b868a BL |
2267 | static int khugepaged_find_target_node(void) |
2268 | { | |
2269 | return 0; | |
2270 | } | |
2271 | ||
10dc4155 BL |
2272 | static inline struct page *alloc_hugepage(int defrag) |
2273 | { | |
2274 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), | |
2275 | HPAGE_PMD_ORDER); | |
2276 | } | |
2277 | ||
26234f36 XG |
2278 | static struct page *khugepaged_alloc_hugepage(bool *wait) |
2279 | { | |
2280 | struct page *hpage; | |
2281 | ||
2282 | do { | |
2283 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2284 | if (!hpage) { | |
2285 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2286 | if (!*wait) | |
2287 | return NULL; | |
2288 | ||
2289 | *wait = false; | |
2290 | khugepaged_alloc_sleep(); | |
2291 | } else | |
2292 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2293 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2294 | ||
2295 | return hpage; | |
2296 | } | |
2297 | ||
2298 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2299 | { | |
2300 | if (!*hpage) | |
2301 | *hpage = khugepaged_alloc_hugepage(wait); | |
2302 | ||
2303 | if (unlikely(!*hpage)) | |
2304 | return false; | |
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 | { | |
2314 | up_read(&mm->mmap_sem); | |
2315 | VM_BUG_ON(!*hpage); | |
2316 | return *hpage; | |
2317 | } | |
692e0b35 AA |
2318 | #endif |
2319 | ||
fa475e51 BL |
2320 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2321 | { | |
2322 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2323 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2324 | return false; | |
2325 | ||
2326 | if (!vma->anon_vma || vma->vm_ops) | |
2327 | return false; | |
2328 | if (is_vma_temporary_stack(vma)) | |
2329 | return false; | |
2330 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2331 | return true; | |
2332 | } | |
2333 | ||
26234f36 XG |
2334 | static void collapse_huge_page(struct mm_struct *mm, |
2335 | unsigned long address, | |
2336 | struct page **hpage, | |
2337 | struct vm_area_struct *vma, | |
2338 | int node) | |
2339 | { | |
26234f36 XG |
2340 | pmd_t *pmd, _pmd; |
2341 | pte_t *pte; | |
2342 | pgtable_t pgtable; | |
2343 | struct page *new_page; | |
c4088ebd | 2344 | spinlock_t *pmd_ptl, *pte_ptl; |
26234f36 XG |
2345 | int isolated; |
2346 | unsigned long hstart, hend; | |
2ec74c3e SG |
2347 | unsigned long mmun_start; /* For mmu_notifiers */ |
2348 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2349 | |
2350 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2351 | ||
2352 | /* release the mmap_sem read lock. */ | |
2353 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2354 | if (!new_page) | |
2355 | return; | |
2356 | ||
420256ef | 2357 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2358 | return; |
ba76149f AA |
2359 | |
2360 | /* | |
2361 | * Prevent all access to pagetables with the exception of | |
2362 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2363 | * handled by the anon_vma lock + PG_lock. | |
2364 | */ | |
2365 | down_write(&mm->mmap_sem); | |
2366 | if (unlikely(khugepaged_test_exit(mm))) | |
2367 | goto out; | |
2368 | ||
2369 | vma = find_vma(mm, address); | |
a8f531eb L |
2370 | if (!vma) |
2371 | goto out; | |
ba76149f AA |
2372 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2373 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2374 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2375 | goto out; | |
fa475e51 | 2376 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2377 | goto out; |
6219049a BL |
2378 | pmd = mm_find_pmd(mm, address); |
2379 | if (!pmd) | |
ba76149f | 2380 | goto out; |
6219049a | 2381 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2382 | goto out; |
2383 | ||
4fc3f1d6 | 2384 | anon_vma_lock_write(vma->anon_vma); |
ba76149f AA |
2385 | |
2386 | pte = pte_offset_map(pmd, address); | |
c4088ebd | 2387 | pte_ptl = pte_lockptr(mm, pmd); |
ba76149f | 2388 | |
2ec74c3e SG |
2389 | mmun_start = address; |
2390 | mmun_end = address + HPAGE_PMD_SIZE; | |
2391 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
c4088ebd | 2392 | pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ |
ba76149f AA |
2393 | /* |
2394 | * After this gup_fast can't run anymore. This also removes | |
2395 | * any huge TLB entry from the CPU so we won't allow | |
2396 | * huge and small TLB entries for the same virtual address | |
2397 | * to avoid the risk of CPU bugs in that area. | |
2398 | */ | |
2ec74c3e | 2399 | _pmd = pmdp_clear_flush(vma, address, pmd); |
c4088ebd | 2400 | spin_unlock(pmd_ptl); |
2ec74c3e | 2401 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f | 2402 | |
c4088ebd | 2403 | spin_lock(pte_ptl); |
ba76149f | 2404 | isolated = __collapse_huge_page_isolate(vma, address, pte); |
c4088ebd | 2405 | spin_unlock(pte_ptl); |
ba76149f AA |
2406 | |
2407 | if (unlikely(!isolated)) { | |
453c7192 | 2408 | pte_unmap(pte); |
c4088ebd | 2409 | spin_lock(pmd_ptl); |
ba76149f | 2410 | BUG_ON(!pmd_none(*pmd)); |
7c342512 AK |
2411 | /* |
2412 | * We can only use set_pmd_at when establishing | |
2413 | * hugepmds and never for establishing regular pmds that | |
2414 | * points to regular pagetables. Use pmd_populate for that | |
2415 | */ | |
2416 | pmd_populate(mm, pmd, pmd_pgtable(_pmd)); | |
c4088ebd | 2417 | spin_unlock(pmd_ptl); |
08b52706 | 2418 | anon_vma_unlock_write(vma->anon_vma); |
ce83d217 | 2419 | goto out; |
ba76149f AA |
2420 | } |
2421 | ||
2422 | /* | |
2423 | * All pages are isolated and locked so anon_vma rmap | |
2424 | * can't run anymore. | |
2425 | */ | |
08b52706 | 2426 | anon_vma_unlock_write(vma->anon_vma); |
ba76149f | 2427 | |
c4088ebd | 2428 | __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); |
453c7192 | 2429 | pte_unmap(pte); |
ba76149f AA |
2430 | __SetPageUptodate(new_page); |
2431 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2432 | |
3122359a KS |
2433 | _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); |
2434 | _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); | |
ba76149f AA |
2435 | |
2436 | /* | |
2437 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2438 | * this is needed to avoid the copy_huge_page writes to become | |
2439 | * visible after the set_pmd_at() write. | |
2440 | */ | |
2441 | smp_wmb(); | |
2442 | ||
c4088ebd | 2443 | spin_lock(pmd_ptl); |
ba76149f AA |
2444 | BUG_ON(!pmd_none(*pmd)); |
2445 | page_add_new_anon_rmap(new_page, vma, address); | |
fce144b4 | 2446 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
ba76149f | 2447 | set_pmd_at(mm, address, pmd, _pmd); |
b113da65 | 2448 | update_mmu_cache_pmd(vma, address, pmd); |
c4088ebd | 2449 | spin_unlock(pmd_ptl); |
ba76149f AA |
2450 | |
2451 | *hpage = NULL; | |
420256ef | 2452 | |
ba76149f | 2453 | khugepaged_pages_collapsed++; |
ce83d217 | 2454 | out_up_write: |
ba76149f | 2455 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2456 | return; |
2457 | ||
ce83d217 | 2458 | out: |
678ff896 | 2459 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2460 | goto out_up_write; |
ba76149f AA |
2461 | } |
2462 | ||
2463 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2464 | struct vm_area_struct *vma, | |
2465 | unsigned long address, | |
2466 | struct page **hpage) | |
2467 | { | |
ba76149f AA |
2468 | pmd_t *pmd; |
2469 | pte_t *pte, *_pte; | |
2470 | int ret = 0, referenced = 0, none = 0; | |
2471 | struct page *page; | |
2472 | unsigned long _address; | |
2473 | spinlock_t *ptl; | |
00ef2d2f | 2474 | int node = NUMA_NO_NODE; |
ba76149f AA |
2475 | |
2476 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2477 | ||
6219049a BL |
2478 | pmd = mm_find_pmd(mm, address); |
2479 | if (!pmd) | |
ba76149f | 2480 | goto out; |
6219049a | 2481 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2482 | goto out; |
2483 | ||
9f1b868a | 2484 | memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); |
ba76149f AA |
2485 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); |
2486 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2487 | _pte++, _address += PAGE_SIZE) { | |
2488 | pte_t pteval = *_pte; | |
2489 | if (pte_none(pteval)) { | |
2490 | if (++none <= khugepaged_max_ptes_none) | |
2491 | continue; | |
2492 | else | |
2493 | goto out_unmap; | |
2494 | } | |
2495 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2496 | goto out_unmap; | |
2497 | page = vm_normal_page(vma, _address, pteval); | |
2498 | if (unlikely(!page)) | |
2499 | goto out_unmap; | |
5c4b4be3 | 2500 | /* |
9f1b868a BL |
2501 | * Record which node the original page is from and save this |
2502 | * information to khugepaged_node_load[]. | |
2503 | * Khupaged will allocate hugepage from the node has the max | |
2504 | * hit record. | |
5c4b4be3 | 2505 | */ |
9f1b868a BL |
2506 | node = page_to_nid(page); |
2507 | khugepaged_node_load[node]++; | |
309381fe | 2508 | VM_BUG_ON_PAGE(PageCompound(page), page); |
ba76149f AA |
2509 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) |
2510 | goto out_unmap; | |
2511 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2512 | if (page_count(page) != 1) | |
2513 | goto out_unmap; | |
8ee53820 AA |
2514 | if (pte_young(pteval) || PageReferenced(page) || |
2515 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2516 | referenced = 1; |
2517 | } | |
2518 | if (referenced) | |
2519 | ret = 1; | |
2520 | out_unmap: | |
2521 | pte_unmap_unlock(pte, ptl); | |
9f1b868a BL |
2522 | if (ret) { |
2523 | node = khugepaged_find_target_node(); | |
ce83d217 | 2524 | /* collapse_huge_page will return with the mmap_sem released */ |
5c4b4be3 | 2525 | collapse_huge_page(mm, address, hpage, vma, node); |
9f1b868a | 2526 | } |
ba76149f AA |
2527 | out: |
2528 | return ret; | |
2529 | } | |
2530 | ||
2531 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2532 | { | |
2533 | struct mm_struct *mm = mm_slot->mm; | |
2534 | ||
b9980cdc | 2535 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2536 | |
2537 | if (khugepaged_test_exit(mm)) { | |
2538 | /* free mm_slot */ | |
43b5fbbd | 2539 | hash_del(&mm_slot->hash); |
ba76149f AA |
2540 | list_del(&mm_slot->mm_node); |
2541 | ||
2542 | /* | |
2543 | * Not strictly needed because the mm exited already. | |
2544 | * | |
2545 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2546 | */ | |
2547 | ||
2548 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2549 | free_mm_slot(mm_slot); | |
2550 | mmdrop(mm); | |
2551 | } | |
2552 | } | |
2553 | ||
2554 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2555 | struct page **hpage) | |
2f1da642 HS |
2556 | __releases(&khugepaged_mm_lock) |
2557 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2558 | { |
2559 | struct mm_slot *mm_slot; | |
2560 | struct mm_struct *mm; | |
2561 | struct vm_area_struct *vma; | |
2562 | int progress = 0; | |
2563 | ||
2564 | VM_BUG_ON(!pages); | |
b9980cdc | 2565 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2566 | |
2567 | if (khugepaged_scan.mm_slot) | |
2568 | mm_slot = khugepaged_scan.mm_slot; | |
2569 | else { | |
2570 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2571 | struct mm_slot, mm_node); | |
2572 | khugepaged_scan.address = 0; | |
2573 | khugepaged_scan.mm_slot = mm_slot; | |
2574 | } | |
2575 | spin_unlock(&khugepaged_mm_lock); | |
2576 | ||
2577 | mm = mm_slot->mm; | |
2578 | down_read(&mm->mmap_sem); | |
2579 | if (unlikely(khugepaged_test_exit(mm))) | |
2580 | vma = NULL; | |
2581 | else | |
2582 | vma = find_vma(mm, khugepaged_scan.address); | |
2583 | ||
2584 | progress++; | |
2585 | for (; vma; vma = vma->vm_next) { | |
2586 | unsigned long hstart, hend; | |
2587 | ||
2588 | cond_resched(); | |
2589 | if (unlikely(khugepaged_test_exit(mm))) { | |
2590 | progress++; | |
2591 | break; | |
2592 | } | |
fa475e51 BL |
2593 | if (!hugepage_vma_check(vma)) { |
2594 | skip: | |
ba76149f AA |
2595 | progress++; |
2596 | continue; | |
2597 | } | |
ba76149f AA |
2598 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2599 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2600 | if (hstart >= hend) |
2601 | goto skip; | |
2602 | if (khugepaged_scan.address > hend) | |
2603 | goto skip; | |
ba76149f AA |
2604 | if (khugepaged_scan.address < hstart) |
2605 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2606 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2607 | |
2608 | while (khugepaged_scan.address < hend) { | |
2609 | int ret; | |
2610 | cond_resched(); | |
2611 | if (unlikely(khugepaged_test_exit(mm))) | |
2612 | goto breakouterloop; | |
2613 | ||
2614 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2615 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2616 | hend); | |
2617 | ret = khugepaged_scan_pmd(mm, vma, | |
2618 | khugepaged_scan.address, | |
2619 | hpage); | |
2620 | /* move to next address */ | |
2621 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2622 | progress += HPAGE_PMD_NR; | |
2623 | if (ret) | |
2624 | /* we released mmap_sem so break loop */ | |
2625 | goto breakouterloop_mmap_sem; | |
2626 | if (progress >= pages) | |
2627 | goto breakouterloop; | |
2628 | } | |
2629 | } | |
2630 | breakouterloop: | |
2631 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2632 | breakouterloop_mmap_sem: | |
2633 | ||
2634 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2635 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2636 | /* |
2637 | * Release the current mm_slot if this mm is about to die, or | |
2638 | * if we scanned all vmas of this mm. | |
2639 | */ | |
2640 | if (khugepaged_test_exit(mm) || !vma) { | |
2641 | /* | |
2642 | * Make sure that if mm_users is reaching zero while | |
2643 | * khugepaged runs here, khugepaged_exit will find | |
2644 | * mm_slot not pointing to the exiting mm. | |
2645 | */ | |
2646 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2647 | khugepaged_scan.mm_slot = list_entry( | |
2648 | mm_slot->mm_node.next, | |
2649 | struct mm_slot, mm_node); | |
2650 | khugepaged_scan.address = 0; | |
2651 | } else { | |
2652 | khugepaged_scan.mm_slot = NULL; | |
2653 | khugepaged_full_scans++; | |
2654 | } | |
2655 | ||
2656 | collect_mm_slot(mm_slot); | |
2657 | } | |
2658 | ||
2659 | return progress; | |
2660 | } | |
2661 | ||
2662 | static int khugepaged_has_work(void) | |
2663 | { | |
2664 | return !list_empty(&khugepaged_scan.mm_head) && | |
2665 | khugepaged_enabled(); | |
2666 | } | |
2667 | ||
2668 | static int khugepaged_wait_event(void) | |
2669 | { | |
2670 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2671 | kthread_should_stop(); |
ba76149f AA |
2672 | } |
2673 | ||
d516904b | 2674 | static void khugepaged_do_scan(void) |
ba76149f | 2675 | { |
d516904b | 2676 | struct page *hpage = NULL; |
ba76149f AA |
2677 | unsigned int progress = 0, pass_through_head = 0; |
2678 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2679 | bool wait = true; |
ba76149f AA |
2680 | |
2681 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2682 | ||
2683 | while (progress < pages) { | |
26234f36 | 2684 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2685 | break; |
26234f36 | 2686 | |
420256ef | 2687 | cond_resched(); |
ba76149f | 2688 | |
878aee7d AA |
2689 | if (unlikely(kthread_should_stop() || freezing(current))) |
2690 | break; | |
2691 | ||
ba76149f AA |
2692 | spin_lock(&khugepaged_mm_lock); |
2693 | if (!khugepaged_scan.mm_slot) | |
2694 | pass_through_head++; | |
2695 | if (khugepaged_has_work() && | |
2696 | pass_through_head < 2) | |
2697 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2698 | &hpage); |
ba76149f AA |
2699 | else |
2700 | progress = pages; | |
2701 | spin_unlock(&khugepaged_mm_lock); | |
2702 | } | |
ba76149f | 2703 | |
d516904b XG |
2704 | if (!IS_ERR_OR_NULL(hpage)) |
2705 | put_page(hpage); | |
0bbbc0b3 AA |
2706 | } |
2707 | ||
2017c0bf XG |
2708 | static void khugepaged_wait_work(void) |
2709 | { | |
2710 | try_to_freeze(); | |
2711 | ||
2712 | if (khugepaged_has_work()) { | |
2713 | if (!khugepaged_scan_sleep_millisecs) | |
2714 | return; | |
2715 | ||
2716 | wait_event_freezable_timeout(khugepaged_wait, | |
2717 | kthread_should_stop(), | |
2718 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2719 | return; | |
2720 | } | |
2721 | ||
2722 | if (khugepaged_enabled()) | |
2723 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2724 | } | |
2725 | ||
ba76149f AA |
2726 | static int khugepaged(void *none) |
2727 | { | |
2728 | struct mm_slot *mm_slot; | |
2729 | ||
878aee7d | 2730 | set_freezable(); |
ba76149f AA |
2731 | set_user_nice(current, 19); |
2732 | ||
b7231789 XG |
2733 | while (!kthread_should_stop()) { |
2734 | khugepaged_do_scan(); | |
2735 | khugepaged_wait_work(); | |
2736 | } | |
ba76149f AA |
2737 | |
2738 | spin_lock(&khugepaged_mm_lock); | |
2739 | mm_slot = khugepaged_scan.mm_slot; | |
2740 | khugepaged_scan.mm_slot = NULL; | |
2741 | if (mm_slot) | |
2742 | collect_mm_slot(mm_slot); | |
2743 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2744 | return 0; |
2745 | } | |
2746 | ||
c5a647d0 KS |
2747 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2748 | unsigned long haddr, pmd_t *pmd) | |
2749 | { | |
2750 | struct mm_struct *mm = vma->vm_mm; | |
2751 | pgtable_t pgtable; | |
2752 | pmd_t _pmd; | |
2753 | int i; | |
2754 | ||
2755 | pmdp_clear_flush(vma, haddr, pmd); | |
2756 | /* leave pmd empty until pte is filled */ | |
2757 | ||
6b0b50b0 | 2758 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
c5a647d0 KS |
2759 | pmd_populate(mm, &_pmd, pgtable); |
2760 | ||
2761 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2762 | pte_t *pte, entry; | |
2763 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2764 | entry = pte_mkspecial(entry); | |
2765 | pte = pte_offset_map(&_pmd, haddr); | |
2766 | VM_BUG_ON(!pte_none(*pte)); | |
2767 | set_pte_at(mm, haddr, pte, entry); | |
2768 | pte_unmap(pte); | |
2769 | } | |
2770 | smp_wmb(); /* make pte visible before pmd */ | |
2771 | pmd_populate(mm, pmd, pgtable); | |
97ae1749 | 2772 | put_huge_zero_page(); |
c5a647d0 KS |
2773 | } |
2774 | ||
e180377f KS |
2775 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2776 | pmd_t *pmd) | |
71e3aac0 | 2777 | { |
c4088ebd | 2778 | spinlock_t *ptl; |
71e3aac0 | 2779 | struct page *page; |
e180377f | 2780 | struct mm_struct *mm = vma->vm_mm; |
c5a647d0 KS |
2781 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2782 | unsigned long mmun_start; /* For mmu_notifiers */ | |
2783 | unsigned long mmun_end; /* For mmu_notifiers */ | |
e180377f KS |
2784 | |
2785 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 | 2786 | |
c5a647d0 KS |
2787 | mmun_start = haddr; |
2788 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
750e8165 | 2789 | again: |
c5a647d0 | 2790 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
c4088ebd | 2791 | ptl = pmd_lock(mm, pmd); |
71e3aac0 | 2792 | if (unlikely(!pmd_trans_huge(*pmd))) { |
c4088ebd | 2793 | spin_unlock(ptl); |
c5a647d0 KS |
2794 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2795 | return; | |
2796 | } | |
2797 | if (is_huge_zero_pmd(*pmd)) { | |
2798 | __split_huge_zero_page_pmd(vma, haddr, pmd); | |
c4088ebd | 2799 | spin_unlock(ptl); |
c5a647d0 | 2800 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2801 | return; |
2802 | } | |
2803 | page = pmd_page(*pmd); | |
309381fe | 2804 | VM_BUG_ON_PAGE(!page_count(page), page); |
71e3aac0 | 2805 | get_page(page); |
c4088ebd | 2806 | spin_unlock(ptl); |
c5a647d0 | 2807 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2808 | |
2809 | split_huge_page(page); | |
2810 | ||
2811 | put_page(page); | |
750e8165 HD |
2812 | |
2813 | /* | |
2814 | * We don't always have down_write of mmap_sem here: a racing | |
2815 | * do_huge_pmd_wp_page() might have copied-on-write to another | |
2816 | * huge page before our split_huge_page() got the anon_vma lock. | |
2817 | */ | |
2818 | if (unlikely(pmd_trans_huge(*pmd))) | |
2819 | goto again; | |
71e3aac0 | 2820 | } |
94fcc585 | 2821 | |
e180377f KS |
2822 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2823 | pmd_t *pmd) | |
2824 | { | |
2825 | struct vm_area_struct *vma; | |
2826 | ||
2827 | vma = find_vma(mm, address); | |
2828 | BUG_ON(vma == NULL); | |
2829 | split_huge_page_pmd(vma, address, pmd); | |
2830 | } | |
2831 | ||
94fcc585 AA |
2832 | static void split_huge_page_address(struct mm_struct *mm, |
2833 | unsigned long address) | |
2834 | { | |
94fcc585 AA |
2835 | pmd_t *pmd; |
2836 | ||
2837 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2838 | ||
6219049a BL |
2839 | pmd = mm_find_pmd(mm, address); |
2840 | if (!pmd) | |
94fcc585 AA |
2841 | return; |
2842 | /* | |
2843 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2844 | * materialize from under us. | |
2845 | */ | |
e180377f | 2846 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2847 | } |
2848 | ||
2849 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2850 | unsigned long start, | |
2851 | unsigned long end, | |
2852 | long adjust_next) | |
2853 | { | |
2854 | /* | |
2855 | * If the new start address isn't hpage aligned and it could | |
2856 | * previously contain an hugepage: check if we need to split | |
2857 | * an huge pmd. | |
2858 | */ | |
2859 | if (start & ~HPAGE_PMD_MASK && | |
2860 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2861 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2862 | split_huge_page_address(vma->vm_mm, start); | |
2863 | ||
2864 | /* | |
2865 | * If the new end address isn't hpage aligned and it could | |
2866 | * previously contain an hugepage: check if we need to split | |
2867 | * an huge pmd. | |
2868 | */ | |
2869 | if (end & ~HPAGE_PMD_MASK && | |
2870 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2871 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2872 | split_huge_page_address(vma->vm_mm, end); | |
2873 | ||
2874 | /* | |
2875 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2876 | * vm_next->vm_start isn't page aligned and it could previously | |
2877 | * contain an hugepage: check if we need to split an huge pmd. | |
2878 | */ | |
2879 | if (adjust_next > 0) { | |
2880 | struct vm_area_struct *next = vma->vm_next; | |
2881 | unsigned long nstart = next->vm_start; | |
2882 | nstart += adjust_next << PAGE_SHIFT; | |
2883 | if (nstart & ~HPAGE_PMD_MASK && | |
2884 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2885 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2886 | split_huge_page_address(next->vm_mm, nstart); | |
2887 | } | |
2888 | } |