blob: 362c329b83fe7441b4d2119c1e164a54c58fc860 [file] [log] [blame]
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001/*
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>
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -080015#include <linux/shrinker.h>
Andrea Arcangeliba761492011-01-13 15:46:58 -080016#include <linux/mm_inline.h>
17#include <linux/kthread.h>
18#include <linux/khugepaged.h>
Andrea Arcangeli878aee72011-01-13 15:47:10 -080019#include <linux/freezer.h>
Andrea Arcangelia664b2d2011-01-13 15:47:17 -080020#include <linux/mman.h>
Ralf Baechle325adeb2012-10-15 13:44:56 +020021#include <linux/pagemap.h>
Mel Gorman4daae3b2012-11-02 11:33:45 +000022#include <linux/migrate.h>
Sasha Levin43b5fbb2013-02-22 16:32:27 -080023#include <linux/hashtable.h>
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -080024
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -080025#include <asm/tlb.h>
26#include <asm/pgalloc.h>
27#include "internal.h"
28
Andrea Arcangeliba761492011-01-13 15:46:58 -080029/*
30 * By default transparent hugepage support is enabled for all mappings
31 * and khugepaged scans all mappings. Defrag is only invoked by
32 * khugepaged hugepage allocations and by page faults inside
33 * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived
34 * allocations.
35 */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -080036unsigned long transparent_hugepage_flags __read_mostly =
Andrea Arcangeli13ece882011-01-13 15:47:07 -080037#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
Andrea Arcangeliba761492011-01-13 15:46:58 -080038 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
Andrea Arcangeli13ece882011-01-13 15:47:07 -080039#endif
40#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
41 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
42#endif
Andrea Arcangelid39d33c2011-01-13 15:47:05 -080043 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
Kirill A. Shutemov79da5402012-12-12 13:51:12 -080044 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
45 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
Andrea Arcangeliba761492011-01-13 15:46:58 -080046
47/* default scan 8*512 pte (or vmas) every 30 second */
48static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8;
49static unsigned int khugepaged_pages_collapsed;
50static unsigned int khugepaged_full_scans;
51static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000;
52/* during fragmentation poll the hugepage allocator once every minute */
53static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000;
54static struct task_struct *khugepaged_thread __read_mostly;
55static DEFINE_MUTEX(khugepaged_mutex);
56static DEFINE_SPINLOCK(khugepaged_mm_lock);
57static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
58/*
59 * default collapse hugepages if there is at least one pte mapped like
60 * it would have happened if the vma was large enough during page
61 * fault.
62 */
63static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1;
64
65static int khugepaged(void *none);
Andrea Arcangeliba761492011-01-13 15:46:58 -080066static int khugepaged_slab_init(void);
Andrea Arcangeliba761492011-01-13 15:46:58 -080067
Sasha Levin43b5fbb2013-02-22 16:32:27 -080068#define MM_SLOTS_HASH_BITS 10
69static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
70
Andrea Arcangeliba761492011-01-13 15:46:58 -080071static struct kmem_cache *mm_slot_cache __read_mostly;
72
73/**
74 * struct mm_slot - hash lookup from mm to mm_slot
75 * @hash: hash collision list
76 * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
77 * @mm: the mm that this information is valid for
78 */
79struct mm_slot {
80 struct hlist_node hash;
81 struct list_head mm_node;
82 struct mm_struct *mm;
83};
84
85/**
86 * struct khugepaged_scan - cursor for scanning
87 * @mm_head: the head of the mm list to scan
88 * @mm_slot: the current mm_slot we are scanning
89 * @address: the next address inside that to be scanned
90 *
91 * There is only the one khugepaged_scan instance of this cursor structure.
92 */
93struct khugepaged_scan {
94 struct list_head mm_head;
95 struct mm_slot *mm_slot;
96 unsigned long address;
H Hartley Sweeten2f1da642011-10-31 17:09:25 -070097};
98static struct khugepaged_scan khugepaged_scan = {
Andrea Arcangeliba761492011-01-13 15:46:58 -080099 .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
100};
101
Andrea Arcangelif0005652011-01-13 15:47:04 -0800102
103static int set_recommended_min_free_kbytes(void)
104{
105 struct zone *zone;
106 int nr_zones = 0;
107 unsigned long recommended_min;
Andrea Arcangelif0005652011-01-13 15:47:04 -0800108
Xiao Guangrong17c230a2012-10-08 16:29:56 -0700109 if (!khugepaged_enabled())
Andrea Arcangelif0005652011-01-13 15:47:04 -0800110 return 0;
111
112 for_each_populated_zone(zone)
113 nr_zones++;
114
115 /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */
116 recommended_min = pageblock_nr_pages * nr_zones * 2;
117
118 /*
119 * Make sure that on average at least two pageblocks are almost free
120 * of another type, one for a migratetype to fall back to and a
121 * second to avoid subsequent fallbacks of other types There are 3
122 * MIGRATE_TYPES we care about.
123 */
124 recommended_min += pageblock_nr_pages * nr_zones *
125 MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
126
127 /* don't ever allow to reserve more than 5% of the lowmem */
128 recommended_min = min(recommended_min,
129 (unsigned long) nr_free_buffer_pages() / 20);
130 recommended_min <<= (PAGE_SHIFT-10);
131
132 if (recommended_min > min_free_kbytes)
133 min_free_kbytes = recommended_min;
134 setup_per_zone_wmarks();
135 return 0;
136}
137late_initcall(set_recommended_min_free_kbytes);
138
Andrea Arcangeliba761492011-01-13 15:46:58 -0800139static int start_khugepaged(void)
140{
141 int err = 0;
142 if (khugepaged_enabled()) {
Andrea Arcangeliba761492011-01-13 15:46:58 -0800143 if (!khugepaged_thread)
144 khugepaged_thread = kthread_run(khugepaged, NULL,
145 "khugepaged");
146 if (unlikely(IS_ERR(khugepaged_thread))) {
147 printk(KERN_ERR
148 "khugepaged: kthread_run(khugepaged) failed\n");
149 err = PTR_ERR(khugepaged_thread);
150 khugepaged_thread = NULL;
151 }
Xiao Guangrong911891a2012-10-08 16:29:41 -0700152
153 if (!list_empty(&khugepaged_scan.mm_head))
Andrea Arcangeliba761492011-01-13 15:46:58 -0800154 wake_up_interruptible(&khugepaged_wait);
Andrea Arcangelif0005652011-01-13 15:47:04 -0800155
156 set_recommended_min_free_kbytes();
Xiao Guangrong911891a2012-10-08 16:29:41 -0700157 } else if (khugepaged_thread) {
Xiao Guangrong911891a2012-10-08 16:29:41 -0700158 kthread_stop(khugepaged_thread);
159 khugepaged_thread = NULL;
160 }
Xiao Guangrong637e3a22012-10-08 16:29:38 -0700161
Andrea Arcangeliba761492011-01-13 15:46:58 -0800162 return err;
163}
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800164
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800165static atomic_t huge_zero_refcount;
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700166static struct page *huge_zero_page __read_mostly;
Kirill A. Shutemov4a6c1292012-12-12 13:50:47 -0800167
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700168static inline bool is_huge_zero_page(struct page *page)
Kirill A. Shutemov4a6c1292012-12-12 13:50:47 -0800169{
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700170 return ACCESS_ONCE(huge_zero_page) == page;
Kirill A. Shutemov4a6c1292012-12-12 13:50:47 -0800171}
172
173static inline bool is_huge_zero_pmd(pmd_t pmd)
174{
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700175 return is_huge_zero_page(pmd_page(pmd));
Kirill A. Shutemov4a6c1292012-12-12 13:50:47 -0800176}
177
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700178static struct page *get_huge_zero_page(void)
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800179{
180 struct page *zero_page;
181retry:
182 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700183 return ACCESS_ONCE(huge_zero_page);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800184
185 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
186 HPAGE_PMD_ORDER);
Kirill A. Shutemovd8a8e1f2012-12-12 13:51:09 -0800187 if (!zero_page) {
188 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700189 return NULL;
Kirill A. Shutemovd8a8e1f2012-12-12 13:51:09 -0800190 }
191 count_vm_event(THP_ZERO_PAGE_ALLOC);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800192 preempt_disable();
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700193 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800194 preempt_enable();
195 __free_page(zero_page);
196 goto retry;
197 }
198
199 /* We take additional reference here. It will be put back by shrinker */
200 atomic_set(&huge_zero_refcount, 2);
201 preempt_enable();
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700202 return ACCESS_ONCE(huge_zero_page);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800203}
204
205static void put_huge_zero_page(void)
206{
207 /*
208 * Counter should never go to zero here. Only shrinker can put
209 * last reference.
210 */
211 BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
212}
213
214static int shrink_huge_zero_page(struct shrinker *shrink,
215 struct shrink_control *sc)
216{
217 if (!sc->nr_to_scan)
218 /* we can free zero page only if last reference remains */
219 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
220
221 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700222 struct page *zero_page = xchg(&huge_zero_page, NULL);
223 BUG_ON(zero_page == NULL);
224 __free_page(zero_page);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800225 }
226
227 return 0;
228}
229
230static struct shrinker huge_zero_page_shrinker = {
231 .shrink = shrink_huge_zero_page,
232 .seeks = DEFAULT_SEEKS,
233};
234
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800235#ifdef CONFIG_SYSFS
Andrea Arcangeliba761492011-01-13 15:46:58 -0800236
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800237static ssize_t double_flag_show(struct kobject *kobj,
238 struct kobj_attribute *attr, char *buf,
239 enum transparent_hugepage_flag enabled,
240 enum transparent_hugepage_flag req_madv)
241{
242 if (test_bit(enabled, &transparent_hugepage_flags)) {
243 VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags));
244 return sprintf(buf, "[always] madvise never\n");
245 } else if (test_bit(req_madv, &transparent_hugepage_flags))
246 return sprintf(buf, "always [madvise] never\n");
247 else
248 return sprintf(buf, "always madvise [never]\n");
249}
250static ssize_t double_flag_store(struct kobject *kobj,
251 struct kobj_attribute *attr,
252 const char *buf, size_t count,
253 enum transparent_hugepage_flag enabled,
254 enum transparent_hugepage_flag req_madv)
255{
256 if (!memcmp("always", buf,
257 min(sizeof("always")-1, count))) {
258 set_bit(enabled, &transparent_hugepage_flags);
259 clear_bit(req_madv, &transparent_hugepage_flags);
260 } else if (!memcmp("madvise", buf,
261 min(sizeof("madvise")-1, count))) {
262 clear_bit(enabled, &transparent_hugepage_flags);
263 set_bit(req_madv, &transparent_hugepage_flags);
264 } else if (!memcmp("never", buf,
265 min(sizeof("never")-1, count))) {
266 clear_bit(enabled, &transparent_hugepage_flags);
267 clear_bit(req_madv, &transparent_hugepage_flags);
268 } else
269 return -EINVAL;
270
271 return count;
272}
273
274static ssize_t enabled_show(struct kobject *kobj,
275 struct kobj_attribute *attr, char *buf)
276{
277 return double_flag_show(kobj, attr, buf,
278 TRANSPARENT_HUGEPAGE_FLAG,
279 TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
280}
281static ssize_t enabled_store(struct kobject *kobj,
282 struct kobj_attribute *attr,
283 const char *buf, size_t count)
284{
Andrea Arcangeliba761492011-01-13 15:46:58 -0800285 ssize_t ret;
286
287 ret = double_flag_store(kobj, attr, buf, count,
288 TRANSPARENT_HUGEPAGE_FLAG,
289 TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
290
291 if (ret > 0) {
Xiao Guangrong911891a2012-10-08 16:29:41 -0700292 int err;
293
294 mutex_lock(&khugepaged_mutex);
295 err = start_khugepaged();
296 mutex_unlock(&khugepaged_mutex);
297
Andrea Arcangeliba761492011-01-13 15:46:58 -0800298 if (err)
299 ret = err;
300 }
301
302 return ret;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800303}
304static struct kobj_attribute enabled_attr =
305 __ATTR(enabled, 0644, enabled_show, enabled_store);
306
307static ssize_t single_flag_show(struct kobject *kobj,
308 struct kobj_attribute *attr, char *buf,
309 enum transparent_hugepage_flag flag)
310{
Ben Hutchingse27e6152011-04-14 15:22:21 -0700311 return sprintf(buf, "%d\n",
312 !!test_bit(flag, &transparent_hugepage_flags));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800313}
Ben Hutchingse27e6152011-04-14 15:22:21 -0700314
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800315static ssize_t single_flag_store(struct kobject *kobj,
316 struct kobj_attribute *attr,
317 const char *buf, size_t count,
318 enum transparent_hugepage_flag flag)
319{
Ben Hutchingse27e6152011-04-14 15:22:21 -0700320 unsigned long value;
321 int ret;
322
323 ret = kstrtoul(buf, 10, &value);
324 if (ret < 0)
325 return ret;
326 if (value > 1)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800327 return -EINVAL;
328
Ben Hutchingse27e6152011-04-14 15:22:21 -0700329 if (value)
330 set_bit(flag, &transparent_hugepage_flags);
331 else
332 clear_bit(flag, &transparent_hugepage_flags);
333
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800334 return count;
335}
336
337/*
338 * Currently defrag only disables __GFP_NOWAIT for allocation. A blind
339 * __GFP_REPEAT is too aggressive, it's never worth swapping tons of
340 * memory just to allocate one more hugepage.
341 */
342static ssize_t defrag_show(struct kobject *kobj,
343 struct kobj_attribute *attr, char *buf)
344{
345 return double_flag_show(kobj, attr, buf,
346 TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
347 TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG);
348}
349static ssize_t defrag_store(struct kobject *kobj,
350 struct kobj_attribute *attr,
351 const char *buf, size_t count)
352{
353 return double_flag_store(kobj, attr, buf, count,
354 TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
355 TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG);
356}
357static struct kobj_attribute defrag_attr =
358 __ATTR(defrag, 0644, defrag_show, defrag_store);
359
Kirill A. Shutemov79da5402012-12-12 13:51:12 -0800360static ssize_t use_zero_page_show(struct kobject *kobj,
361 struct kobj_attribute *attr, char *buf)
362{
363 return single_flag_show(kobj, attr, buf,
364 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
365}
366static ssize_t use_zero_page_store(struct kobject *kobj,
367 struct kobj_attribute *attr, const char *buf, size_t count)
368{
369 return single_flag_store(kobj, attr, buf, count,
370 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
371}
372static struct kobj_attribute use_zero_page_attr =
373 __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800374#ifdef CONFIG_DEBUG_VM
375static ssize_t debug_cow_show(struct kobject *kobj,
376 struct kobj_attribute *attr, char *buf)
377{
378 return single_flag_show(kobj, attr, buf,
379 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
380}
381static ssize_t debug_cow_store(struct kobject *kobj,
382 struct kobj_attribute *attr,
383 const char *buf, size_t count)
384{
385 return single_flag_store(kobj, attr, buf, count,
386 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
387}
388static struct kobj_attribute debug_cow_attr =
389 __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store);
390#endif /* CONFIG_DEBUG_VM */
391
392static struct attribute *hugepage_attr[] = {
393 &enabled_attr.attr,
394 &defrag_attr.attr,
Kirill A. Shutemov79da5402012-12-12 13:51:12 -0800395 &use_zero_page_attr.attr,
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800396#ifdef CONFIG_DEBUG_VM
397 &debug_cow_attr.attr,
398#endif
399 NULL,
400};
401
402static struct attribute_group hugepage_attr_group = {
403 .attrs = hugepage_attr,
Andrea Arcangeliba761492011-01-13 15:46:58 -0800404};
405
406static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
407 struct kobj_attribute *attr,
408 char *buf)
409{
410 return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs);
411}
412
413static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
414 struct kobj_attribute *attr,
415 const char *buf, size_t count)
416{
417 unsigned long msecs;
418 int err;
419
420 err = strict_strtoul(buf, 10, &msecs);
421 if (err || msecs > UINT_MAX)
422 return -EINVAL;
423
424 khugepaged_scan_sleep_millisecs = msecs;
425 wake_up_interruptible(&khugepaged_wait);
426
427 return count;
428}
429static struct kobj_attribute scan_sleep_millisecs_attr =
430 __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show,
431 scan_sleep_millisecs_store);
432
433static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj,
434 struct kobj_attribute *attr,
435 char *buf)
436{
437 return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs);
438}
439
440static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj,
441 struct kobj_attribute *attr,
442 const char *buf, size_t count)
443{
444 unsigned long msecs;
445 int err;
446
447 err = strict_strtoul(buf, 10, &msecs);
448 if (err || msecs > UINT_MAX)
449 return -EINVAL;
450
451 khugepaged_alloc_sleep_millisecs = msecs;
452 wake_up_interruptible(&khugepaged_wait);
453
454 return count;
455}
456static struct kobj_attribute alloc_sleep_millisecs_attr =
457 __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show,
458 alloc_sleep_millisecs_store);
459
460static ssize_t pages_to_scan_show(struct kobject *kobj,
461 struct kobj_attribute *attr,
462 char *buf)
463{
464 return sprintf(buf, "%u\n", khugepaged_pages_to_scan);
465}
466static ssize_t pages_to_scan_store(struct kobject *kobj,
467 struct kobj_attribute *attr,
468 const char *buf, size_t count)
469{
470 int err;
471 unsigned long pages;
472
473 err = strict_strtoul(buf, 10, &pages);
474 if (err || !pages || pages > UINT_MAX)
475 return -EINVAL;
476
477 khugepaged_pages_to_scan = pages;
478
479 return count;
480}
481static struct kobj_attribute pages_to_scan_attr =
482 __ATTR(pages_to_scan, 0644, pages_to_scan_show,
483 pages_to_scan_store);
484
485static ssize_t pages_collapsed_show(struct kobject *kobj,
486 struct kobj_attribute *attr,
487 char *buf)
488{
489 return sprintf(buf, "%u\n", khugepaged_pages_collapsed);
490}
491static struct kobj_attribute pages_collapsed_attr =
492 __ATTR_RO(pages_collapsed);
493
494static ssize_t full_scans_show(struct kobject *kobj,
495 struct kobj_attribute *attr,
496 char *buf)
497{
498 return sprintf(buf, "%u\n", khugepaged_full_scans);
499}
500static struct kobj_attribute full_scans_attr =
501 __ATTR_RO(full_scans);
502
503static ssize_t khugepaged_defrag_show(struct kobject *kobj,
504 struct kobj_attribute *attr, char *buf)
505{
506 return single_flag_show(kobj, attr, buf,
507 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
508}
509static ssize_t khugepaged_defrag_store(struct kobject *kobj,
510 struct kobj_attribute *attr,
511 const char *buf, size_t count)
512{
513 return single_flag_store(kobj, attr, buf, count,
514 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
515}
516static struct kobj_attribute khugepaged_defrag_attr =
517 __ATTR(defrag, 0644, khugepaged_defrag_show,
518 khugepaged_defrag_store);
519
520/*
521 * max_ptes_none controls if khugepaged should collapse hugepages over
522 * any unmapped ptes in turn potentially increasing the memory
523 * footprint of the vmas. When max_ptes_none is 0 khugepaged will not
524 * reduce the available free memory in the system as it
525 * runs. Increasing max_ptes_none will instead potentially reduce the
526 * free memory in the system during the khugepaged scan.
527 */
528static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj,
529 struct kobj_attribute *attr,
530 char *buf)
531{
532 return sprintf(buf, "%u\n", khugepaged_max_ptes_none);
533}
534static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj,
535 struct kobj_attribute *attr,
536 const char *buf, size_t count)
537{
538 int err;
539 unsigned long max_ptes_none;
540
541 err = strict_strtoul(buf, 10, &max_ptes_none);
542 if (err || max_ptes_none > HPAGE_PMD_NR-1)
543 return -EINVAL;
544
545 khugepaged_max_ptes_none = max_ptes_none;
546
547 return count;
548}
549static struct kobj_attribute khugepaged_max_ptes_none_attr =
550 __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show,
551 khugepaged_max_ptes_none_store);
552
553static struct attribute *khugepaged_attr[] = {
554 &khugepaged_defrag_attr.attr,
555 &khugepaged_max_ptes_none_attr.attr,
556 &pages_to_scan_attr.attr,
557 &pages_collapsed_attr.attr,
558 &full_scans_attr.attr,
559 &scan_sleep_millisecs_attr.attr,
560 &alloc_sleep_millisecs_attr.attr,
561 NULL,
562};
563
564static struct attribute_group khugepaged_attr_group = {
565 .attrs = khugepaged_attr,
566 .name = "khugepaged",
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800567};
Shaohua Li569e5592012-01-12 17:19:11 -0800568
569static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
570{
571 int err;
572
573 *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
574 if (unlikely(!*hugepage_kobj)) {
Jeremy Eder2c797372012-12-20 15:05:32 -0800575 printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n");
Shaohua Li569e5592012-01-12 17:19:11 -0800576 return -ENOMEM;
577 }
578
579 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
580 if (err) {
Jeremy Eder2c797372012-12-20 15:05:32 -0800581 printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
Shaohua Li569e5592012-01-12 17:19:11 -0800582 goto delete_obj;
583 }
584
585 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
586 if (err) {
Jeremy Eder2c797372012-12-20 15:05:32 -0800587 printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
Shaohua Li569e5592012-01-12 17:19:11 -0800588 goto remove_hp_group;
589 }
590
591 return 0;
592
593remove_hp_group:
594 sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group);
595delete_obj:
596 kobject_put(*hugepage_kobj);
597 return err;
598}
599
600static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj)
601{
602 sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
603 sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
604 kobject_put(hugepage_kobj);
605}
606#else
607static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj)
608{
609 return 0;
610}
611
612static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj)
613{
614}
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800615#endif /* CONFIG_SYSFS */
616
617static int __init hugepage_init(void)
618{
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800619 int err;
Shaohua Li569e5592012-01-12 17:19:11 -0800620 struct kobject *hugepage_kobj;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800621
Andrea Arcangeli4b7167b2011-01-13 15:47:09 -0800622 if (!has_transparent_hugepage()) {
623 transparent_hugepage_flags = 0;
Shaohua Li569e5592012-01-12 17:19:11 -0800624 return -EINVAL;
Andrea Arcangeli4b7167b2011-01-13 15:47:09 -0800625 }
626
Shaohua Li569e5592012-01-12 17:19:11 -0800627 err = hugepage_init_sysfs(&hugepage_kobj);
628 if (err)
629 return err;
Andrea Arcangeliba761492011-01-13 15:46:58 -0800630
631 err = khugepaged_slab_init();
632 if (err)
633 goto out;
634
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800635 register_shrinker(&huge_zero_page_shrinker);
636
Rik van Riel97562cd2011-01-13 15:47:12 -0800637 /*
638 * By default disable transparent hugepages on smaller systems,
639 * where the extra memory used could hurt more than TLB overhead
640 * is likely to save. The admin can still enable it through /sys.
641 */
642 if (totalram_pages < (512 << (20 - PAGE_SHIFT)))
643 transparent_hugepage_flags = 0;
644
Andrea Arcangeliba761492011-01-13 15:46:58 -0800645 start_khugepaged();
646
Shaohua Li569e5592012-01-12 17:19:11 -0800647 return 0;
Andrea Arcangeliba761492011-01-13 15:46:58 -0800648out:
Shaohua Li569e5592012-01-12 17:19:11 -0800649 hugepage_exit_sysfs(hugepage_kobj);
Andrea Arcangeliba761492011-01-13 15:46:58 -0800650 return err;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800651}
652module_init(hugepage_init)
653
654static int __init setup_transparent_hugepage(char *str)
655{
656 int ret = 0;
657 if (!str)
658 goto out;
659 if (!strcmp(str, "always")) {
660 set_bit(TRANSPARENT_HUGEPAGE_FLAG,
661 &transparent_hugepage_flags);
662 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
663 &transparent_hugepage_flags);
664 ret = 1;
665 } else if (!strcmp(str, "madvise")) {
666 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
667 &transparent_hugepage_flags);
668 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
669 &transparent_hugepage_flags);
670 ret = 1;
671 } else if (!strcmp(str, "never")) {
672 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
673 &transparent_hugepage_flags);
674 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
675 &transparent_hugepage_flags);
676 ret = 1;
677 }
678out:
679 if (!ret)
680 printk(KERN_WARNING
681 "transparent_hugepage= cannot parse, ignored\n");
682 return ret;
683}
684__setup("transparent_hugepage=", setup_transparent_hugepage);
685
Mel Gormanb32967f2012-11-19 12:35:47 +0000686pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800687{
688 if (likely(vma->vm_flags & VM_WRITE))
689 pmd = pmd_mkwrite(pmd);
690 return pmd;
691}
692
Bob Liub3092b32012-12-11 16:00:41 -0800693static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma)
694{
695 pmd_t entry;
696 entry = mk_pmd(page, vma->vm_page_prot);
697 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
698 entry = pmd_mkhuge(entry);
699 return entry;
700}
701
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800702static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
703 struct vm_area_struct *vma,
704 unsigned long haddr, pmd_t *pmd,
705 struct page *page)
706{
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800707 pgtable_t pgtable;
708
709 VM_BUG_ON(!PageCompound(page));
710 pgtable = pte_alloc_one(mm, haddr);
David Rientjesedad9d22012-05-29 15:06:17 -0700711 if (unlikely(!pgtable))
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800712 return VM_FAULT_OOM;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800713
714 clear_huge_page(page, haddr, HPAGE_PMD_NR);
Minchan Kim52f37622013-04-29 15:08:15 -0700715 /*
716 * The memory barrier inside __SetPageUptodate makes sure that
717 * clear_huge_page writes become visible before the set_pmd_at()
718 * write.
719 */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800720 __SetPageUptodate(page);
721
722 spin_lock(&mm->page_table_lock);
723 if (unlikely(!pmd_none(*pmd))) {
724 spin_unlock(&mm->page_table_lock);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -0800725 mem_cgroup_uncharge_page(page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800726 put_page(page);
727 pte_free(mm, pgtable);
728 } else {
729 pmd_t entry;
Bob Liub3092b32012-12-11 16:00:41 -0800730 entry = mk_huge_pmd(page, vma);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800731 page_add_new_anon_rmap(page, vma, haddr);
732 set_pmd_at(mm, haddr, pmd, entry);
Gerald Schaefere3ebcf642012-10-08 16:30:07 -0700733 pgtable_trans_huge_deposit(mm, pgtable);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800734 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
Andrea Arcangeli1c641e82012-03-05 14:59:20 -0800735 mm->nr_ptes++;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800736 spin_unlock(&mm->page_table_lock);
737 }
738
David Rientjesaa2e8782012-05-29 15:06:17 -0700739 return 0;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800740}
741
Andi Kleencc5d4622011-03-22 16:33:13 -0700742static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp)
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800743{
Andi Kleencc5d4622011-03-22 16:33:13 -0700744 return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp;
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800745}
746
747static inline struct page *alloc_hugepage_vma(int defrag,
748 struct vm_area_struct *vma,
Andi Kleencc5d4622011-03-22 16:33:13 -0700749 unsigned long haddr, int nd,
750 gfp_t extra_gfp)
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800751{
Andi Kleencc5d4622011-03-22 16:33:13 -0700752 return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp),
Andi Kleen5c4b4be2011-03-04 17:36:32 -0800753 HPAGE_PMD_ORDER, vma, haddr, nd);
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800754}
755
756#ifndef CONFIG_NUMA
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800757static inline struct page *alloc_hugepage(int defrag)
758{
Andi Kleencc5d4622011-03-22 16:33:13 -0700759 return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800760 HPAGE_PMD_ORDER);
761}
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800762#endif
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800763
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800764static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800765 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700766 struct page *zero_page)
Kirill A. Shutemovfc9fe822012-12-12 13:50:51 -0800767{
768 pmd_t entry;
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800769 if (!pmd_none(*pmd))
770 return false;
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700771 entry = mk_pmd(zero_page, vma->vm_page_prot);
Kirill A. Shutemovfc9fe822012-12-12 13:50:51 -0800772 entry = pmd_wrprotect(entry);
773 entry = pmd_mkhuge(entry);
774 set_pmd_at(mm, haddr, pmd, entry);
775 pgtable_trans_huge_deposit(mm, pgtable);
776 mm->nr_ptes++;
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800777 return true;
Kirill A. Shutemovfc9fe822012-12-12 13:50:51 -0800778}
779
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800780int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
781 unsigned long address, pmd_t *pmd,
782 unsigned int flags)
783{
784 struct page *page;
785 unsigned long haddr = address & HPAGE_PMD_MASK;
786 pte_t *pte;
787
788 if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) {
789 if (unlikely(anon_vma_prepare(vma)))
790 return VM_FAULT_OOM;
Andrea Arcangeliba761492011-01-13 15:46:58 -0800791 if (unlikely(khugepaged_enter(vma)))
792 return VM_FAULT_OOM;
Kirill A. Shutemov79da5402012-12-12 13:51:12 -0800793 if (!(flags & FAULT_FLAG_WRITE) &&
794 transparent_hugepage_use_zero_page()) {
Kirill A. Shutemov80371952012-12-12 13:51:02 -0800795 pgtable_t pgtable;
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700796 struct page *zero_page;
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800797 bool set;
Kirill A. Shutemov80371952012-12-12 13:51:02 -0800798 pgtable = pte_alloc_one(mm, haddr);
799 if (unlikely(!pgtable))
800 return VM_FAULT_OOM;
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700801 zero_page = get_huge_zero_page();
802 if (unlikely(!zero_page)) {
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800803 pte_free(mm, pgtable);
804 count_vm_event(THP_FAULT_FALLBACK);
805 goto out;
806 }
Kirill A. Shutemov80371952012-12-12 13:51:02 -0800807 spin_lock(&mm->page_table_lock);
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800808 set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd,
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700809 zero_page);
Kirill A. Shutemov80371952012-12-12 13:51:02 -0800810 spin_unlock(&mm->page_table_lock);
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800811 if (!set) {
812 pte_free(mm, pgtable);
813 put_huge_zero_page();
814 }
Kirill A. Shutemov80371952012-12-12 13:51:02 -0800815 return 0;
816 }
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -0800817 page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
Andi Kleencc5d4622011-03-22 16:33:13 -0700818 vma, haddr, numa_node_id(), 0);
Andi Kleen81ab4202011-04-14 15:22:06 -0700819 if (unlikely(!page)) {
820 count_vm_event(THP_FAULT_FALLBACK);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800821 goto out;
Andi Kleen81ab4202011-04-14 15:22:06 -0700822 }
823 count_vm_event(THP_FAULT_ALLOC);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -0800824 if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
825 put_page(page);
826 goto out;
827 }
David Rientjesedad9d22012-05-29 15:06:17 -0700828 if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd,
829 page))) {
830 mem_cgroup_uncharge_page(page);
831 put_page(page);
832 goto out;
833 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800834
David Rientjesedad9d22012-05-29 15:06:17 -0700835 return 0;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800836 }
837out:
838 /*
839 * Use __pte_alloc instead of pte_alloc_map, because we can't
840 * run pte_offset_map on the pmd, if an huge pmd could
841 * materialize from under us from a different thread.
842 */
Mel Gorman4fd01772011-10-12 21:06:51 +0200843 if (unlikely(pmd_none(*pmd)) &&
844 unlikely(__pte_alloc(mm, vma, pmd, address)))
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800845 return VM_FAULT_OOM;
846 /* if an huge pmd materialized from under us just retry later */
847 if (unlikely(pmd_trans_huge(*pmd)))
848 return 0;
849 /*
850 * A regular pmd is established and it can't morph into a huge pmd
851 * from under us anymore at this point because we hold the mmap_sem
852 * read mode and khugepaged takes it in write mode. So now it's
853 * safe to run pte_offset_map().
854 */
855 pte = pte_offset_map(pmd, address);
856 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
857}
858
859int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
860 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
861 struct vm_area_struct *vma)
862{
863 struct page *src_page;
864 pmd_t pmd;
865 pgtable_t pgtable;
866 int ret;
867
868 ret = -ENOMEM;
869 pgtable = pte_alloc_one(dst_mm, addr);
870 if (unlikely(!pgtable))
871 goto out;
872
873 spin_lock(&dst_mm->page_table_lock);
874 spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING);
875
876 ret = -EAGAIN;
877 pmd = *src_pmd;
878 if (unlikely(!pmd_trans_huge(pmd))) {
879 pte_free(dst_mm, pgtable);
880 goto out_unlock;
881 }
Kirill A. Shutemovfc9fe822012-12-12 13:50:51 -0800882 /*
883 * mm->page_table_lock is enough to be sure that huge zero pmd is not
884 * under splitting since we don't split the page itself, only pmd to
885 * a page table.
886 */
887 if (is_huge_zero_pmd(pmd)) {
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700888 struct page *zero_page;
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800889 bool set;
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -0800890 /*
891 * get_huge_zero_page() will never allocate a new page here,
892 * since we already have a zero page to copy. It just takes a
893 * reference.
894 */
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700895 zero_page = get_huge_zero_page();
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800896 set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd,
Kirill A. Shutemov5918d102013-04-29 15:08:44 -0700897 zero_page);
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800898 BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */
Kirill A. Shutemovfc9fe822012-12-12 13:50:51 -0800899 ret = 0;
900 goto out_unlock;
901 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800902 if (unlikely(pmd_trans_splitting(pmd))) {
903 /* split huge page running from under us */
904 spin_unlock(&src_mm->page_table_lock);
905 spin_unlock(&dst_mm->page_table_lock);
906 pte_free(dst_mm, pgtable);
907
908 wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */
909 goto out;
910 }
911 src_page = pmd_page(pmd);
912 VM_BUG_ON(!PageHead(src_page));
913 get_page(src_page);
914 page_dup_rmap(src_page);
915 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
916
917 pmdp_set_wrprotect(src_mm, addr, src_pmd);
918 pmd = pmd_mkold(pmd_wrprotect(pmd));
919 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
Gerald Schaefere3ebcf642012-10-08 16:30:07 -0700920 pgtable_trans_huge_deposit(dst_mm, pgtable);
Andrea Arcangeli1c641e82012-03-05 14:59:20 -0800921 dst_mm->nr_ptes++;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800922
923 ret = 0;
924out_unlock:
925 spin_unlock(&src_mm->page_table_lock);
926 spin_unlock(&dst_mm->page_table_lock);
927out:
928 return ret;
929}
930
Will Deacona1dd4502012-12-11 16:01:27 -0800931void huge_pmd_set_accessed(struct mm_struct *mm,
932 struct vm_area_struct *vma,
933 unsigned long address,
934 pmd_t *pmd, pmd_t orig_pmd,
935 int dirty)
936{
937 pmd_t entry;
938 unsigned long haddr;
939
940 spin_lock(&mm->page_table_lock);
941 if (unlikely(!pmd_same(*pmd, orig_pmd)))
942 goto unlock;
943
944 entry = pmd_mkyoung(orig_pmd);
945 haddr = address & HPAGE_PMD_MASK;
946 if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty))
947 update_mmu_cache_pmd(vma, address, pmd);
948
949unlock:
950 spin_unlock(&mm->page_table_lock);
951}
952
Kirill A. Shutemov93b47962012-12-12 13:50:54 -0800953static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
954 struct vm_area_struct *vma, unsigned long address,
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800955 pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr)
Kirill A. Shutemov93b47962012-12-12 13:50:54 -0800956{
957 pgtable_t pgtable;
958 pmd_t _pmd;
959 struct page *page;
960 int i, ret = 0;
961 unsigned long mmun_start; /* For mmu_notifiers */
962 unsigned long mmun_end; /* For mmu_notifiers */
963
964 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
965 if (!page) {
966 ret |= VM_FAULT_OOM;
967 goto out;
968 }
969
970 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
971 put_page(page);
972 ret |= VM_FAULT_OOM;
973 goto out;
974 }
975
976 clear_user_highpage(page, address);
977 __SetPageUptodate(page);
978
979 mmun_start = haddr;
980 mmun_end = haddr + HPAGE_PMD_SIZE;
981 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
982
983 spin_lock(&mm->page_table_lock);
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -0800984 if (unlikely(!pmd_same(*pmd, orig_pmd)))
985 goto out_free_page;
986
Kirill A. Shutemov93b47962012-12-12 13:50:54 -0800987 pmdp_clear_flush(vma, haddr, pmd);
988 /* leave pmd empty until pte is filled */
989
990 pgtable = pgtable_trans_huge_withdraw(mm);
991 pmd_populate(mm, &_pmd, pgtable);
992
993 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
994 pte_t *pte, entry;
995 if (haddr == (address & PAGE_MASK)) {
996 entry = mk_pte(page, vma->vm_page_prot);
997 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
998 page_add_new_anon_rmap(page, vma, haddr);
999 } else {
1000 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
1001 entry = pte_mkspecial(entry);
1002 }
1003 pte = pte_offset_map(&_pmd, haddr);
1004 VM_BUG_ON(!pte_none(*pte));
1005 set_pte_at(mm, haddr, pte, entry);
1006 pte_unmap(pte);
1007 }
1008 smp_wmb(); /* make pte visible before pmd */
1009 pmd_populate(mm, pmd, pgtable);
1010 spin_unlock(&mm->page_table_lock);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -08001011 put_huge_zero_page();
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001012 inc_mm_counter(mm, MM_ANONPAGES);
1013
1014 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1015
1016 ret |= VM_FAULT_WRITE;
1017out:
1018 return ret;
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -08001019out_free_page:
1020 spin_unlock(&mm->page_table_lock);
1021 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1022 mem_cgroup_uncharge_page(page);
1023 put_page(page);
1024 goto out;
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001025}
1026
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001027static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
1028 struct vm_area_struct *vma,
1029 unsigned long address,
1030 pmd_t *pmd, pmd_t orig_pmd,
1031 struct page *page,
1032 unsigned long haddr)
1033{
1034 pgtable_t pgtable;
1035 pmd_t _pmd;
1036 int ret = 0, i;
1037 struct page **pages;
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001038 unsigned long mmun_start; /* For mmu_notifiers */
1039 unsigned long mmun_end; /* For mmu_notifiers */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001040
1041 pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR,
1042 GFP_KERNEL);
1043 if (unlikely(!pages)) {
1044 ret |= VM_FAULT_OOM;
1045 goto out;
1046 }
1047
1048 for (i = 0; i < HPAGE_PMD_NR; i++) {
Andi Kleencc5d4622011-03-22 16:33:13 -07001049 pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE |
1050 __GFP_OTHER_NODE,
Andi Kleen19ee1512011-03-04 17:36:31 -08001051 vma, address, page_to_nid(page));
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001052 if (unlikely(!pages[i] ||
1053 mem_cgroup_newpage_charge(pages[i], mm,
1054 GFP_KERNEL))) {
1055 if (pages[i])
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001056 put_page(pages[i]);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001057 mem_cgroup_uncharge_start();
1058 while (--i >= 0) {
1059 mem_cgroup_uncharge_page(pages[i]);
1060 put_page(pages[i]);
1061 }
1062 mem_cgroup_uncharge_end();
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001063 kfree(pages);
1064 ret |= VM_FAULT_OOM;
1065 goto out;
1066 }
1067 }
1068
1069 for (i = 0; i < HPAGE_PMD_NR; i++) {
1070 copy_user_highpage(pages[i], page + i,
Hillf Danton0089e482011-10-31 17:09:38 -07001071 haddr + PAGE_SIZE * i, vma);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001072 __SetPageUptodate(pages[i]);
1073 cond_resched();
1074 }
1075
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001076 mmun_start = haddr;
1077 mmun_end = haddr + HPAGE_PMD_SIZE;
1078 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1079
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001080 spin_lock(&mm->page_table_lock);
1081 if (unlikely(!pmd_same(*pmd, orig_pmd)))
1082 goto out_free_pages;
1083 VM_BUG_ON(!PageHead(page));
1084
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001085 pmdp_clear_flush(vma, haddr, pmd);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001086 /* leave pmd empty until pte is filled */
1087
Gerald Schaefere3ebcf642012-10-08 16:30:07 -07001088 pgtable = pgtable_trans_huge_withdraw(mm);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001089 pmd_populate(mm, &_pmd, pgtable);
1090
1091 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1092 pte_t *pte, entry;
1093 entry = mk_pte(pages[i], vma->vm_page_prot);
1094 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1095 page_add_new_anon_rmap(pages[i], vma, haddr);
1096 pte = pte_offset_map(&_pmd, haddr);
1097 VM_BUG_ON(!pte_none(*pte));
1098 set_pte_at(mm, haddr, pte, entry);
1099 pte_unmap(pte);
1100 }
1101 kfree(pages);
1102
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001103 smp_wmb(); /* make pte visible before pmd */
1104 pmd_populate(mm, pmd, pgtable);
1105 page_remove_rmap(page);
1106 spin_unlock(&mm->page_table_lock);
1107
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001108 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1109
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001110 ret |= VM_FAULT_WRITE;
1111 put_page(page);
1112
1113out:
1114 return ret;
1115
1116out_free_pages:
1117 spin_unlock(&mm->page_table_lock);
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001118 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001119 mem_cgroup_uncharge_start();
1120 for (i = 0; i < HPAGE_PMD_NR; i++) {
1121 mem_cgroup_uncharge_page(pages[i]);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001122 put_page(pages[i]);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001123 }
1124 mem_cgroup_uncharge_end();
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001125 kfree(pages);
1126 goto out;
1127}
1128
1129int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1130 unsigned long address, pmd_t *pmd, pmd_t orig_pmd)
1131{
1132 int ret = 0;
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001133 struct page *page = NULL, *new_page;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001134 unsigned long haddr;
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001135 unsigned long mmun_start; /* For mmu_notifiers */
1136 unsigned long mmun_end; /* For mmu_notifiers */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001137
1138 VM_BUG_ON(!vma->anon_vma);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001139 haddr = address & HPAGE_PMD_MASK;
1140 if (is_huge_zero_pmd(orig_pmd))
1141 goto alloc;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001142 spin_lock(&mm->page_table_lock);
1143 if (unlikely(!pmd_same(*pmd, orig_pmd)))
1144 goto out_unlock;
1145
1146 page = pmd_page(orig_pmd);
1147 VM_BUG_ON(!PageCompound(page) || !PageHead(page));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001148 if (page_mapcount(page) == 1) {
1149 pmd_t entry;
1150 entry = pmd_mkyoung(orig_pmd);
1151 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1152 if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1))
David Millerb113da62012-10-08 16:34:25 -07001153 update_mmu_cache_pmd(vma, address, pmd);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001154 ret |= VM_FAULT_WRITE;
1155 goto out_unlock;
1156 }
1157 get_page(page);
1158 spin_unlock(&mm->page_table_lock);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001159alloc:
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001160 if (transparent_hugepage_enabled(vma) &&
1161 !transparent_hugepage_debug_cow())
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -08001162 new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
Andi Kleencc5d4622011-03-22 16:33:13 -07001163 vma, haddr, numa_node_id(), 0);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001164 else
1165 new_page = NULL;
1166
1167 if (unlikely(!new_page)) {
Andi Kleen81ab4202011-04-14 15:22:06 -07001168 count_vm_event(THP_FAULT_FALLBACK);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001169 if (is_huge_zero_pmd(orig_pmd)) {
1170 ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
Kirill A. Shutemov3ea41e62012-12-12 13:51:14 -08001171 address, pmd, orig_pmd, haddr);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001172 } else {
1173 ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
1174 pmd, orig_pmd, page, haddr);
1175 if (ret & VM_FAULT_OOM)
1176 split_huge_page(page);
1177 put_page(page);
1178 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001179 goto out;
1180 }
Andi Kleen81ab4202011-04-14 15:22:06 -07001181 count_vm_event(THP_FAULT_ALLOC);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001182
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001183 if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
1184 put_page(new_page);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001185 if (page) {
1186 split_huge_page(page);
1187 put_page(page);
1188 }
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001189 ret |= VM_FAULT_OOM;
1190 goto out;
1191 }
1192
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001193 if (is_huge_zero_pmd(orig_pmd))
1194 clear_huge_page(new_page, haddr, HPAGE_PMD_NR);
1195 else
1196 copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001197 __SetPageUptodate(new_page);
1198
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001199 mmun_start = haddr;
1200 mmun_end = haddr + HPAGE_PMD_SIZE;
1201 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1202
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001203 spin_lock(&mm->page_table_lock);
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001204 if (page)
1205 put_page(page);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001206 if (unlikely(!pmd_same(*pmd, orig_pmd))) {
David Rientjes6f60b692012-05-29 15:06:26 -07001207 spin_unlock(&mm->page_table_lock);
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001208 mem_cgroup_uncharge_page(new_page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001209 put_page(new_page);
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001210 goto out_mn;
Andrea Arcangelib9bbfbe2011-01-13 15:46:57 -08001211 } else {
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001212 pmd_t entry;
Bob Liub3092b32012-12-11 16:00:41 -08001213 entry = mk_huge_pmd(new_page, vma);
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001214 pmdp_clear_flush(vma, haddr, pmd);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001215 page_add_new_anon_rmap(new_page, vma, haddr);
1216 set_pmd_at(mm, haddr, pmd, entry);
David Millerb113da62012-10-08 16:34:25 -07001217 update_mmu_cache_pmd(vma, address, pmd);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -08001218 if (is_huge_zero_pmd(orig_pmd)) {
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001219 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -08001220 put_huge_zero_page();
1221 } else {
Kirill A. Shutemov93b47962012-12-12 13:50:54 -08001222 VM_BUG_ON(!PageHead(page));
1223 page_remove_rmap(page);
1224 put_page(page);
1225 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001226 ret |= VM_FAULT_WRITE;
1227 }
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001228 spin_unlock(&mm->page_table_lock);
1229out_mn:
1230 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1231out:
1232 return ret;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001233out_unlock:
1234 spin_unlock(&mm->page_table_lock);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001235 return ret;
1236}
1237
David Rientjesb676b292012-10-08 16:34:03 -07001238struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001239 unsigned long addr,
1240 pmd_t *pmd,
1241 unsigned int flags)
1242{
David Rientjesb676b292012-10-08 16:34:03 -07001243 struct mm_struct *mm = vma->vm_mm;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001244 struct page *page = NULL;
1245
1246 assert_spin_locked(&mm->page_table_lock);
1247
1248 if (flags & FOLL_WRITE && !pmd_write(*pmd))
1249 goto out;
1250
Kirill A. Shutemov85facf22013-02-04 14:28:42 -08001251 /* Avoid dumping huge zero page */
1252 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1253 return ERR_PTR(-EFAULT);
1254
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001255 page = pmd_page(*pmd);
1256 VM_BUG_ON(!PageHead(page));
1257 if (flags & FOLL_TOUCH) {
1258 pmd_t _pmd;
1259 /*
1260 * We should set the dirty bit only for FOLL_WRITE but
1261 * for now the dirty bit in the pmd is meaningless.
1262 * And if the dirty bit will become meaningful and
1263 * we'll only set it with FOLL_WRITE, an atomic
1264 * set_bit will be required on the pmd to set the
1265 * young bit, instead of the current set_pmd_at.
1266 */
1267 _pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
1268 set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd);
1269 }
David Rientjesb676b292012-10-08 16:34:03 -07001270 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1271 if (page->mapping && trylock_page(page)) {
1272 lru_add_drain();
1273 if (page->mapping)
1274 mlock_vma_page(page);
1275 unlock_page(page);
1276 }
1277 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001278 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1279 VM_BUG_ON(!PageCompound(page));
1280 if (flags & FOLL_GET)
Andrea Arcangeli70b50f92011-11-02 13:36:59 -07001281 get_page_foll(page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001282
1283out:
1284 return page;
1285}
1286
Mel Gormand10e63f2012-10-25 14:16:31 +02001287/* NUMA hinting page fault entry point for trans huge pmds */
Mel Gorman4daae3b2012-11-02 11:33:45 +00001288int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
1289 unsigned long addr, pmd_t pmd, pmd_t *pmdp)
Mel Gormand10e63f2012-10-25 14:16:31 +02001290{
Mel Gormanb32967f2012-11-19 12:35:47 +00001291 struct page *page;
Mel Gormand10e63f2012-10-25 14:16:31 +02001292 unsigned long haddr = addr & HPAGE_PMD_MASK;
Mel Gorman4daae3b2012-11-02 11:33:45 +00001293 int target_nid;
Mel Gorman03c5a6e2012-11-02 14:52:48 +00001294 int current_nid = -1;
Mel Gormanb32967f2012-11-19 12:35:47 +00001295 bool migrated;
Mel Gormand10e63f2012-10-25 14:16:31 +02001296
1297 spin_lock(&mm->page_table_lock);
1298 if (unlikely(!pmd_same(pmd, *pmdp)))
1299 goto out_unlock;
1300
1301 page = pmd_page(pmd);
Mel Gorman4daae3b2012-11-02 11:33:45 +00001302 get_page(page);
Mel Gorman03c5a6e2012-11-02 14:52:48 +00001303 current_nid = page_to_nid(page);
1304 count_vm_numa_event(NUMA_HINT_FAULTS);
1305 if (current_nid == numa_node_id())
1306 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
Mel Gorman4daae3b2012-11-02 11:33:45 +00001307
1308 target_nid = mpol_misplaced(page, vma, haddr);
Mel Gormanb32967f2012-11-19 12:35:47 +00001309 if (target_nid == -1) {
1310 put_page(page);
Mel Gorman4daae3b2012-11-02 11:33:45 +00001311 goto clear_pmdnuma;
Mel Gormanb32967f2012-11-19 12:35:47 +00001312 }
Mel Gorman4daae3b2012-11-02 11:33:45 +00001313
Mel Gormanb32967f2012-11-19 12:35:47 +00001314 /* Acquire the page lock to serialise THP migrations */
1315 spin_unlock(&mm->page_table_lock);
1316 lock_page(page);
Peter Zijlstracbee9f82012-10-25 14:16:43 +02001317
Mel Gormanb32967f2012-11-19 12:35:47 +00001318 /* Confirm the PTE did not while locked */
1319 spin_lock(&mm->page_table_lock);
1320 if (unlikely(!pmd_same(pmd, *pmdp))) {
1321 unlock_page(page);
1322 put_page(page);
1323 goto out_unlock;
1324 }
1325 spin_unlock(&mm->page_table_lock);
1326
1327 /* Migrate the THP to the requested node */
1328 migrated = migrate_misplaced_transhuge_page(mm, vma,
Hugh Dickins340ef392013-02-22 16:34:33 -08001329 pmdp, pmd, addr, page, target_nid);
1330 if (!migrated)
1331 goto check_same;
Mel Gormanb32967f2012-11-19 12:35:47 +00001332
Hugh Dickins340ef392013-02-22 16:34:33 -08001333 task_numa_fault(target_nid, HPAGE_PMD_NR, true);
Mel Gorman4daae3b2012-11-02 11:33:45 +00001334 return 0;
1335
Hugh Dickins340ef392013-02-22 16:34:33 -08001336check_same:
1337 spin_lock(&mm->page_table_lock);
1338 if (unlikely(!pmd_same(pmd, *pmdp)))
1339 goto out_unlock;
Mel Gorman4daae3b2012-11-02 11:33:45 +00001340clear_pmdnuma:
Mel Gormand10e63f2012-10-25 14:16:31 +02001341 pmd = pmd_mknonnuma(pmd);
1342 set_pmd_at(mm, haddr, pmdp, pmd);
1343 VM_BUG_ON(pmd_numa(*pmdp));
1344 update_mmu_cache_pmd(vma, addr, pmdp);
Mel Gormand10e63f2012-10-25 14:16:31 +02001345out_unlock:
1346 spin_unlock(&mm->page_table_lock);
Mel Gormanb32967f2012-11-19 12:35:47 +00001347 if (current_nid != -1)
Hugh Dickins340ef392013-02-22 16:34:33 -08001348 task_numa_fault(current_nid, HPAGE_PMD_NR, false);
Mel Gormand10e63f2012-10-25 14:16:31 +02001349 return 0;
1350}
1351
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001352int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
Shaohua Lif21760b2012-01-12 17:19:16 -08001353 pmd_t *pmd, unsigned long addr)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001354{
1355 int ret = 0;
1356
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001357 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1358 struct page *page;
1359 pgtable_t pgtable;
David Millerf5c8ad42012-10-08 16:34:26 -07001360 pmd_t orig_pmd;
Gerald Schaefere3ebcf642012-10-08 16:30:07 -07001361 pgtable = pgtable_trans_huge_withdraw(tlb->mm);
David Millerf5c8ad42012-10-08 16:34:26 -07001362 orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001363 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
Kirill A. Shutemov479f0ab2012-12-12 13:50:50 -08001364 if (is_huge_zero_pmd(orig_pmd)) {
1365 tlb->mm->nr_ptes--;
1366 spin_unlock(&tlb->mm->page_table_lock);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -08001367 put_huge_zero_page();
Kirill A. Shutemov479f0ab2012-12-12 13:50:50 -08001368 } else {
1369 page = pmd_page(orig_pmd);
1370 page_remove_rmap(page);
1371 VM_BUG_ON(page_mapcount(page) < 0);
1372 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1373 VM_BUG_ON(!PageHead(page));
1374 tlb->mm->nr_ptes--;
1375 spin_unlock(&tlb->mm->page_table_lock);
1376 tlb_remove_page(tlb, page);
1377 }
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001378 pte_free(tlb->mm, pgtable);
1379 ret = 1;
1380 }
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001381 return ret;
1382}
1383
Johannes Weiner0ca16342011-01-13 15:47:02 -08001384int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1385 unsigned long addr, unsigned long end,
1386 unsigned char *vec)
1387{
1388 int ret = 0;
1389
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001390 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1391 /*
1392 * All logical pages in the range are present
1393 * if backed by a huge page.
1394 */
Johannes Weiner0ca16342011-01-13 15:47:02 -08001395 spin_unlock(&vma->vm_mm->page_table_lock);
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001396 memset(vec, 1, (end - addr) >> PAGE_SHIFT);
1397 ret = 1;
1398 }
Johannes Weiner0ca16342011-01-13 15:47:02 -08001399
1400 return ret;
1401}
1402
Andrea Arcangeli37a1c492011-10-31 17:08:30 -07001403int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
1404 unsigned long old_addr,
1405 unsigned long new_addr, unsigned long old_end,
1406 pmd_t *old_pmd, pmd_t *new_pmd)
1407{
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
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001428 ret = __pmd_trans_huge_lock(old_pmd, vma);
1429 if (ret == 1) {
1430 pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
1431 VM_BUG_ON(!pmd_none(*new_pmd));
1432 set_pmd_at(mm, new_addr, new_pmd, pmd);
Andrea Arcangeli37a1c492011-10-31 17:08:30 -07001433 spin_unlock(&mm->page_table_lock);
1434 }
1435out:
1436 return ret;
1437}
1438
Johannes Weinercd7548a2011-01-13 15:47:04 -08001439int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
Mel Gorman4b10e7d2012-10-25 14:16:32 +02001440 unsigned long addr, pgprot_t newprot, int prot_numa)
Johannes Weinercd7548a2011-01-13 15:47:04 -08001441{
1442 struct mm_struct *mm = vma->vm_mm;
1443 int ret = 0;
1444
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001445 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1446 pmd_t entry;
1447 entry = pmdp_get_and_clear(mm, addr, pmd);
Hugh Dickinsa4f1de12012-12-16 18:56:58 -08001448 if (!prot_numa) {
Mel Gorman4b10e7d2012-10-25 14:16:32 +02001449 entry = pmd_modify(entry, newprot);
Hugh Dickinsa4f1de12012-12-16 18:56:58 -08001450 BUG_ON(pmd_write(entry));
1451 } else {
Mel Gorman4b10e7d2012-10-25 14:16:32 +02001452 struct page *page = pmd_page(*pmd);
1453
1454 /* only check non-shared pages */
1455 if (page_mapcount(page) == 1 &&
1456 !pmd_numa(*pmd)) {
1457 entry = pmd_mknuma(entry);
1458 }
1459 }
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001460 set_pmd_at(mm, addr, pmd, entry);
Johannes Weinercd7548a2011-01-13 15:47:04 -08001461 spin_unlock(&vma->vm_mm->page_table_lock);
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001462 ret = 1;
1463 }
Johannes Weinercd7548a2011-01-13 15:47:04 -08001464
1465 return ret;
1466}
1467
Naoya Horiguchi025c5b22012-03-21 16:33:57 -07001468/*
1469 * Returns 1 if a given pmd maps a stable (not under splitting) thp.
1470 * Returns -1 if it maps a thp under splitting. Returns 0 otherwise.
1471 *
1472 * Note that if it returns 1, this routine returns without unlocking page
1473 * table locks. So callers must unlock them.
1474 */
1475int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
1476{
1477 spin_lock(&vma->vm_mm->page_table_lock);
1478 if (likely(pmd_trans_huge(*pmd))) {
1479 if (unlikely(pmd_trans_splitting(*pmd))) {
1480 spin_unlock(&vma->vm_mm->page_table_lock);
1481 wait_split_huge_page(vma->anon_vma, pmd);
1482 return -1;
1483 } else {
1484 /* Thp mapped by 'pmd' is stable, so we can
1485 * handle it as it is. */
1486 return 1;
1487 }
1488 }
1489 spin_unlock(&vma->vm_mm->page_table_lock);
1490 return 0;
1491}
1492
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001493pmd_t *page_check_address_pmd(struct page *page,
1494 struct mm_struct *mm,
1495 unsigned long address,
1496 enum page_check_address_pmd_flag flag)
1497{
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001498 pmd_t *pmd, *ret = NULL;
1499
1500 if (address & ~HPAGE_PMD_MASK)
1501 goto out;
1502
Bob Liu62190492012-12-11 16:00:37 -08001503 pmd = mm_find_pmd(mm, address);
1504 if (!pmd)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001505 goto out;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001506 if (pmd_none(*pmd))
1507 goto out;
1508 if (pmd_page(*pmd) != page)
1509 goto out;
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08001510 /*
1511 * split_vma() may create temporary aliased mappings. There is
1512 * no risk as long as all huge pmd are found and have their
1513 * splitting bit set before __split_huge_page_refcount
1514 * runs. Finding the same huge pmd more than once during the
1515 * same rmap walk is not a problem.
1516 */
1517 if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG &&
1518 pmd_trans_splitting(*pmd))
1519 goto out;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001520 if (pmd_trans_huge(*pmd)) {
1521 VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG &&
1522 !pmd_trans_splitting(*pmd));
1523 ret = pmd;
1524 }
1525out:
1526 return ret;
1527}
1528
1529static int __split_huge_page_splitting(struct page *page,
1530 struct vm_area_struct *vma,
1531 unsigned long address)
1532{
1533 struct mm_struct *mm = vma->vm_mm;
1534 pmd_t *pmd;
1535 int ret = 0;
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001536 /* For mmu_notifiers */
1537 const unsigned long mmun_start = address;
1538 const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001539
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001540 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001541 spin_lock(&mm->page_table_lock);
1542 pmd = page_check_address_pmd(page, mm, address,
1543 PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG);
1544 if (pmd) {
1545 /*
1546 * We can't temporarily set the pmd to null in order
1547 * to split it, the pmd must remain marked huge at all
1548 * times or the VM won't take the pmd_trans_huge paths
Ingo Molnar5a505082012-12-02 19:56:46 +00001549 * and it won't wait on the anon_vma->root->rwsem to
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001550 * serialize against split_huge_page*.
1551 */
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001552 pmdp_splitting_flush(vma, address, pmd);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001553 ret = 1;
1554 }
1555 spin_unlock(&mm->page_table_lock);
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07001556 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001557
1558 return ret;
1559}
1560
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001561static void __split_huge_page_refcount(struct page *page,
1562 struct list_head *list)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001563{
1564 int i;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001565 struct zone *zone = page_zone(page);
Hugh Dickinsfa9add62012-05-29 15:07:09 -07001566 struct lruvec *lruvec;
Andrea Arcangeli70b50f92011-11-02 13:36:59 -07001567 int tail_count = 0;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001568
1569 /* prevent PageLRU to go away from under us, and freeze lru stats */
1570 spin_lock_irq(&zone->lru_lock);
Hugh Dickinsfa9add62012-05-29 15:07:09 -07001571 lruvec = mem_cgroup_page_lruvec(page, zone);
1572
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001573 compound_lock(page);
KAMEZAWA Hiroyukie94c8a92012-01-12 17:18:20 -08001574 /* complete memcg works before add pages to LRU */
1575 mem_cgroup_split_huge_fixup(page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001576
Shaohua Li45676882012-01-12 17:19:18 -08001577 for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001578 struct page *page_tail = page + i;
1579
Andrea Arcangeli70b50f92011-11-02 13:36:59 -07001580 /* tail_page->_mapcount cannot change */
1581 BUG_ON(page_mapcount(page_tail) < 0);
1582 tail_count += page_mapcount(page_tail);
1583 /* check for overflow */
1584 BUG_ON(tail_count < 0);
1585 BUG_ON(atomic_read(&page_tail->_count) != 0);
1586 /*
1587 * tail_page->_count is zero and not changing from
1588 * under us. But get_page_unless_zero() may be running
1589 * from under us on the tail_page. If we used
1590 * atomic_set() below instead of atomic_add(), we
1591 * would then run atomic_set() concurrently with
1592 * get_page_unless_zero(), and atomic_set() is
1593 * implemented in C not using locked ops. spin_unlock
1594 * on x86 sometime uses locked ops because of PPro
1595 * errata 66, 92, so unless somebody can guarantee
1596 * atomic_set() here would be safe on all archs (and
1597 * not only on x86), it's safer to use atomic_add().
1598 */
1599 atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1,
1600 &page_tail->_count);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001601
1602 /* after clearing PageTail the gup refcount can be released */
1603 smp_mb();
1604
Jin Dongminga6d30dd2011-02-01 15:52:40 -08001605 /*
1606 * retain hwpoison flag of the poisoned tail page:
1607 * fix for the unsuitable process killed on Guest Machine(KVM)
1608 * by the memory-failure.
1609 */
1610 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON;
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001611 page_tail->flags |= (page->flags &
1612 ((1L << PG_referenced) |
1613 (1L << PG_swapbacked) |
1614 (1L << PG_mlocked) |
1615 (1L << PG_uptodate)));
1616 page_tail->flags |= (1L << PG_dirty);
1617
Andrea Arcangeli70b50f92011-11-02 13:36:59 -07001618 /* clear PageTail before overwriting first_page */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001619 smp_wmb();
1620
1621 /*
1622 * __split_huge_page_splitting() already set the
1623 * splitting bit in all pmd that could map this
1624 * hugepage, that will ensure no CPU can alter the
1625 * mapcount on the head page. The mapcount is only
1626 * accounted in the head page and it has to be
1627 * transferred to all tail pages in the below code. So
1628 * for this code to be safe, the split the mapcount
1629 * can't change. But that doesn't mean userland can't
1630 * keep changing and reading the page contents while
1631 * we transfer the mapcount, so the pmd splitting
1632 * status is achieved setting a reserved bit in the
1633 * pmd, not by clearing the present bit.
1634 */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001635 page_tail->_mapcount = page->_mapcount;
1636
1637 BUG_ON(page_tail->mapping);
1638 page_tail->mapping = page->mapping;
1639
Shaohua Li45676882012-01-12 17:19:18 -08001640 page_tail->index = page->index + i;
Mel Gorman22b751c2013-02-22 16:34:59 -08001641 page_nid_xchg_last(page_tail, page_nid_last(page));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001642
1643 BUG_ON(!PageAnon(page_tail));
1644 BUG_ON(!PageUptodate(page_tail));
1645 BUG_ON(!PageDirty(page_tail));
1646 BUG_ON(!PageSwapBacked(page_tail));
1647
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001648 lru_add_page_tail(page, page_tail, lruvec, list);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001649 }
Andrea Arcangeli70b50f92011-11-02 13:36:59 -07001650 atomic_sub(tail_count, &page->_count);
1651 BUG_ON(atomic_read(&page->_count) <= 0);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001652
Hugh Dickinsfa9add62012-05-29 15:07:09 -07001653 __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1);
Andrea Arcangeli79134172011-01-13 15:46:58 -08001654 __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR);
1655
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001656 ClearPageCompound(page);
1657 compound_unlock(page);
1658 spin_unlock_irq(&zone->lru_lock);
1659
1660 for (i = 1; i < HPAGE_PMD_NR; i++) {
1661 struct page *page_tail = page + i;
1662 BUG_ON(page_count(page_tail) <= 0);
1663 /*
1664 * Tail pages may be freed if there wasn't any mapping
1665 * like if add_to_swap() is running on a lru page that
1666 * had its mapping zapped. And freeing these pages
1667 * requires taking the lru_lock so we do the put_page
1668 * of the tail pages after the split is complete.
1669 */
1670 put_page(page_tail);
1671 }
1672
1673 /*
1674 * Only the head page (now become a regular page) is required
1675 * to be pinned by the caller.
1676 */
1677 BUG_ON(page_count(page) <= 0);
1678}
1679
1680static int __split_huge_page_map(struct page *page,
1681 struct vm_area_struct *vma,
1682 unsigned long address)
1683{
1684 struct mm_struct *mm = vma->vm_mm;
1685 pmd_t *pmd, _pmd;
1686 int ret = 0, i;
1687 pgtable_t pgtable;
1688 unsigned long haddr;
1689
1690 spin_lock(&mm->page_table_lock);
1691 pmd = page_check_address_pmd(page, mm, address,
1692 PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
1693 if (pmd) {
Gerald Schaefere3ebcf642012-10-08 16:30:07 -07001694 pgtable = pgtable_trans_huge_withdraw(mm);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001695 pmd_populate(mm, &_pmd, pgtable);
1696
Gerald Schaefere3ebcf642012-10-08 16:30:07 -07001697 haddr = address;
1698 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001699 pte_t *pte, entry;
1700 BUG_ON(PageCompound(page+i));
1701 entry = mk_pte(page + i, vma->vm_page_prot);
1702 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1703 if (!pmd_write(*pmd))
1704 entry = pte_wrprotect(entry);
1705 else
1706 BUG_ON(page_mapcount(page) != 1);
1707 if (!pmd_young(*pmd))
1708 entry = pte_mkold(entry);
Andrea Arcangeli1ba6e0b2012-10-04 01:51:06 +02001709 if (pmd_numa(*pmd))
1710 entry = pte_mknuma(entry);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001711 pte = pte_offset_map(&_pmd, haddr);
1712 BUG_ON(!pte_none(*pte));
1713 set_pte_at(mm, haddr, pte, entry);
1714 pte_unmap(pte);
1715 }
1716
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001717 smp_wmb(); /* make pte visible before pmd */
1718 /*
1719 * Up to this point the pmd is present and huge and
1720 * userland has the whole access to the hugepage
1721 * during the split (which happens in place). If we
1722 * overwrite the pmd with the not-huge version
1723 * pointing to the pte here (which of course we could
1724 * if all CPUs were bug free), userland could trigger
1725 * a small page size TLB miss on the small sized TLB
1726 * while the hugepage TLB entry is still established
1727 * in the huge TLB. Some CPU doesn't like that. See
1728 * http://support.amd.com/us/Processor_TechDocs/41322.pdf,
1729 * Erratum 383 on page 93. Intel should be safe but is
1730 * also warns that it's only safe if the permission
1731 * and cache attributes of the two entries loaded in
1732 * the two TLB is identical (which should be the case
1733 * here). But it is generally safer to never allow
1734 * small and huge TLB entries for the same virtual
1735 * address to be loaded simultaneously. So instead of
1736 * doing "pmd_populate(); flush_tlb_range();" we first
1737 * mark the current pmd notpresent (atomically because
1738 * here the pmd_trans_huge and pmd_trans_splitting
1739 * must remain set at all times on the pmd until the
1740 * split is complete for this pmd), then we flush the
1741 * SMP TLB and finally we write the non-huge version
1742 * of the pmd entry with pmd_populate.
1743 */
Gerald Schaefer46dcde72012-10-08 16:30:09 -07001744 pmdp_invalidate(vma, address, pmd);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001745 pmd_populate(mm, pmd, pgtable);
1746 ret = 1;
1747 }
1748 spin_unlock(&mm->page_table_lock);
1749
1750 return ret;
1751}
1752
Ingo Molnar5a505082012-12-02 19:56:46 +00001753/* must be called with anon_vma->root->rwsem held */
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001754static void __split_huge_page(struct page *page,
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001755 struct anon_vma *anon_vma,
1756 struct list_head *list)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001757{
1758 int mapcount, mapcount2;
Michel Lespinassebf181b92012-10-08 16:31:39 -07001759 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001760 struct anon_vma_chain *avc;
1761
1762 BUG_ON(!PageHead(page));
1763 BUG_ON(PageTail(page));
1764
1765 mapcount = 0;
Michel Lespinassebf181b92012-10-08 16:31:39 -07001766 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001767 struct vm_area_struct *vma = avc->vma;
1768 unsigned long addr = vma_address(page, vma);
1769 BUG_ON(is_vma_temporary_stack(vma));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001770 mapcount += __split_huge_page_splitting(page, vma, addr);
1771 }
Andrea Arcangeli05759d32011-01-13 15:46:53 -08001772 /*
1773 * It is critical that new vmas are added to the tail of the
1774 * anon_vma list. This guarantes that if copy_huge_pmd() runs
1775 * and establishes a child pmd before
1776 * __split_huge_page_splitting() freezes the parent pmd (so if
1777 * we fail to prevent copy_huge_pmd() from running until the
1778 * whole __split_huge_page() is complete), we will still see
1779 * the newly established pmd of the child later during the
1780 * walk, to be able to set it as pmd_trans_splitting too.
1781 */
1782 if (mapcount != page_mapcount(page))
1783 printk(KERN_ERR "mapcount %d page_mapcount %d\n",
1784 mapcount, page_mapcount(page));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001785 BUG_ON(mapcount != page_mapcount(page));
1786
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001787 __split_huge_page_refcount(page, list);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001788
1789 mapcount2 = 0;
Michel Lespinassebf181b92012-10-08 16:31:39 -07001790 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001791 struct vm_area_struct *vma = avc->vma;
1792 unsigned long addr = vma_address(page, vma);
1793 BUG_ON(is_vma_temporary_stack(vma));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001794 mapcount2 += __split_huge_page_map(page, vma, addr);
1795 }
Andrea Arcangeli05759d32011-01-13 15:46:53 -08001796 if (mapcount != mapcount2)
1797 printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n",
1798 mapcount, mapcount2, page_mapcount(page));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001799 BUG_ON(mapcount != mapcount2);
1800}
1801
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001802/*
1803 * Split a hugepage into normal pages. This doesn't change the position of head
1804 * page. If @list is null, tail pages will be added to LRU list, otherwise, to
1805 * @list. Both head page and tail pages will inherit mapping, flags, and so on
1806 * from the hugepage.
1807 * Return 0 if the hugepage is split successfully otherwise return 1.
1808 */
1809int split_huge_page_to_list(struct page *page, struct list_head *list)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001810{
1811 struct anon_vma *anon_vma;
1812 int ret = 1;
1813
Kirill A. Shutemov5918d102013-04-29 15:08:44 -07001814 BUG_ON(is_huge_zero_page(page));
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001815 BUG_ON(!PageAnon(page));
Mel Gorman062f1af2013-01-11 14:32:02 -08001816
1817 /*
1818 * The caller does not necessarily hold an mmap_sem that would prevent
1819 * the anon_vma disappearing so we first we take a reference to it
1820 * and then lock the anon_vma for write. This is similar to
1821 * page_lock_anon_vma_read except the write lock is taken to serialise
1822 * against parallel split or collapse operations.
1823 */
1824 anon_vma = page_get_anon_vma(page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001825 if (!anon_vma)
1826 goto out;
Mel Gorman062f1af2013-01-11 14:32:02 -08001827 anon_vma_lock_write(anon_vma);
1828
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001829 ret = 0;
1830 if (!PageCompound(page))
1831 goto out_unlock;
1832
1833 BUG_ON(!PageSwapBacked(page));
Shaohua Li5bc7b8a2013-04-29 15:08:36 -07001834 __split_huge_page(page, anon_vma, list);
Andi Kleen81ab4202011-04-14 15:22:06 -07001835 count_vm_event(THP_SPLIT);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001836
1837 BUG_ON(PageCompound(page));
1838out_unlock:
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08001839 anon_vma_unlock_write(anon_vma);
Mel Gorman062f1af2013-01-11 14:32:02 -08001840 put_anon_vma(anon_vma);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08001841out:
1842 return ret;
1843}
1844
Konstantin Khlebnikov4b6e1e32012-10-08 16:28:40 -07001845#define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE)
Andrea Arcangeli78f11a22011-04-27 15:26:45 -07001846
Andrea Arcangeli60ab3242011-01-13 15:47:18 -08001847int hugepage_madvise(struct vm_area_struct *vma,
1848 unsigned long *vm_flags, int advice)
Andrea Arcangeli0af4e982011-01-13 15:46:55 -08001849{
Gerald Schaefer8e720332012-10-08 16:30:12 -07001850 struct mm_struct *mm = vma->vm_mm;
1851
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001852 switch (advice) {
1853 case MADV_HUGEPAGE:
1854 /*
1855 * Be somewhat over-protective like KSM for now!
1856 */
Andrea Arcangeli78f11a22011-04-27 15:26:45 -07001857 if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001858 return -EINVAL;
Gerald Schaefer8e720332012-10-08 16:30:12 -07001859 if (mm->def_flags & VM_NOHUGEPAGE)
1860 return -EINVAL;
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001861 *vm_flags &= ~VM_NOHUGEPAGE;
1862 *vm_flags |= VM_HUGEPAGE;
Andrea Arcangeli60ab3242011-01-13 15:47:18 -08001863 /*
1864 * If the vma become good for khugepaged to scan,
1865 * register it here without waiting a page fault that
1866 * may not happen any time soon.
1867 */
1868 if (unlikely(khugepaged_enter_vma_merge(vma)))
1869 return -ENOMEM;
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001870 break;
1871 case MADV_NOHUGEPAGE:
1872 /*
1873 * Be somewhat over-protective like KSM for now!
1874 */
Andrea Arcangeli78f11a22011-04-27 15:26:45 -07001875 if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP))
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001876 return -EINVAL;
1877 *vm_flags &= ~VM_HUGEPAGE;
1878 *vm_flags |= VM_NOHUGEPAGE;
Andrea Arcangeli60ab3242011-01-13 15:47:18 -08001879 /*
1880 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
1881 * this vma even if we leave the mm registered in khugepaged if
1882 * it got registered before VM_NOHUGEPAGE was set.
1883 */
Andrea Arcangelia664b2d2011-01-13 15:47:17 -08001884 break;
1885 }
Andrea Arcangeli0af4e982011-01-13 15:46:55 -08001886
1887 return 0;
1888}
1889
Andrea Arcangeliba761492011-01-13 15:46:58 -08001890static int __init khugepaged_slab_init(void)
1891{
1892 mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
1893 sizeof(struct mm_slot),
1894 __alignof__(struct mm_slot), 0, NULL);
1895 if (!mm_slot_cache)
1896 return -ENOMEM;
1897
1898 return 0;
1899}
1900
Andrea Arcangeliba761492011-01-13 15:46:58 -08001901static inline struct mm_slot *alloc_mm_slot(void)
1902{
1903 if (!mm_slot_cache) /* initialization failed */
1904 return NULL;
1905 return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
1906}
1907
1908static inline void free_mm_slot(struct mm_slot *mm_slot)
1909{
1910 kmem_cache_free(mm_slot_cache, mm_slot);
1911}
1912
Andrea Arcangeliba761492011-01-13 15:46:58 -08001913static struct mm_slot *get_mm_slot(struct mm_struct *mm)
1914{
1915 struct mm_slot *mm_slot;
Andrea Arcangeliba761492011-01-13 15:46:58 -08001916
Sasha Levinb67bfe02013-02-27 17:06:00 -08001917 hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
Andrea Arcangeliba761492011-01-13 15:46:58 -08001918 if (mm == mm_slot->mm)
1919 return mm_slot;
Sasha Levin43b5fbb2013-02-22 16:32:27 -08001920
Andrea Arcangeliba761492011-01-13 15:46:58 -08001921 return NULL;
1922}
1923
1924static void insert_to_mm_slots_hash(struct mm_struct *mm,
1925 struct mm_slot *mm_slot)
1926{
Andrea Arcangeliba761492011-01-13 15:46:58 -08001927 mm_slot->mm = mm;
Sasha Levin43b5fbb2013-02-22 16:32:27 -08001928 hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
Andrea Arcangeliba761492011-01-13 15:46:58 -08001929}
1930
1931static inline int khugepaged_test_exit(struct mm_struct *mm)
1932{
1933 return atomic_read(&mm->mm_users) == 0;
1934}
1935
1936int __khugepaged_enter(struct mm_struct *mm)
1937{
1938 struct mm_slot *mm_slot;
1939 int wakeup;
1940
1941 mm_slot = alloc_mm_slot();
1942 if (!mm_slot)
1943 return -ENOMEM;
1944
1945 /* __khugepaged_exit() must not run from under us */
1946 VM_BUG_ON(khugepaged_test_exit(mm));
1947 if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
1948 free_mm_slot(mm_slot);
1949 return 0;
1950 }
1951
1952 spin_lock(&khugepaged_mm_lock);
1953 insert_to_mm_slots_hash(mm, mm_slot);
1954 /*
1955 * Insert just behind the scanning cursor, to let the area settle
1956 * down a little.
1957 */
1958 wakeup = list_empty(&khugepaged_scan.mm_head);
1959 list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
1960 spin_unlock(&khugepaged_mm_lock);
1961
1962 atomic_inc(&mm->mm_count);
1963 if (wakeup)
1964 wake_up_interruptible(&khugepaged_wait);
1965
1966 return 0;
1967}
1968
1969int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
1970{
1971 unsigned long hstart, hend;
1972 if (!vma->anon_vma)
1973 /*
1974 * Not yet faulted in so we will register later in the
1975 * page fault if needed.
1976 */
1977 return 0;
Andrea Arcangeli78f11a22011-04-27 15:26:45 -07001978 if (vma->vm_ops)
Andrea Arcangeliba761492011-01-13 15:46:58 -08001979 /* khugepaged not yet working on file or special mappings */
1980 return 0;
Konstantin Khlebnikovb3b9c292012-10-08 16:28:34 -07001981 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
Andrea Arcangeliba761492011-01-13 15:46:58 -08001982 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
1983 hend = vma->vm_end & HPAGE_PMD_MASK;
1984 if (hstart < hend)
1985 return khugepaged_enter(vma);
1986 return 0;
1987}
1988
1989void __khugepaged_exit(struct mm_struct *mm)
1990{
1991 struct mm_slot *mm_slot;
1992 int free = 0;
1993
1994 spin_lock(&khugepaged_mm_lock);
1995 mm_slot = get_mm_slot(mm);
1996 if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
Sasha Levin43b5fbb2013-02-22 16:32:27 -08001997 hash_del(&mm_slot->hash);
Andrea Arcangeliba761492011-01-13 15:46:58 -08001998 list_del(&mm_slot->mm_node);
1999 free = 1;
2000 }
Chris Wrightd788e802011-07-25 17:12:14 -07002001 spin_unlock(&khugepaged_mm_lock);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002002
2003 if (free) {
Andrea Arcangeliba761492011-01-13 15:46:58 -08002004 clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
2005 free_mm_slot(mm_slot);
2006 mmdrop(mm);
2007 } else if (mm_slot) {
Andrea Arcangeliba761492011-01-13 15:46:58 -08002008 /*
2009 * This is required to serialize against
2010 * khugepaged_test_exit() (which is guaranteed to run
2011 * under mmap sem read mode). Stop here (after we
2012 * return all pagetables will be destroyed) until
2013 * khugepaged has finished working on the pagetables
2014 * under the mmap_sem.
2015 */
2016 down_write(&mm->mmap_sem);
2017 up_write(&mm->mmap_sem);
Chris Wrightd788e802011-07-25 17:12:14 -07002018 }
Andrea Arcangeliba761492011-01-13 15:46:58 -08002019}
2020
2021static void release_pte_page(struct page *page)
2022{
2023 /* 0 stands for page_is_file_cache(page) == false */
2024 dec_zone_page_state(page, NR_ISOLATED_ANON + 0);
2025 unlock_page(page);
2026 putback_lru_page(page);
2027}
2028
2029static void release_pte_pages(pte_t *pte, pte_t *_pte)
2030{
2031 while (--_pte >= pte) {
2032 pte_t pteval = *_pte;
2033 if (!pte_none(pteval))
2034 release_pte_page(pte_page(pteval));
2035 }
2036}
2037
Andrea Arcangeliba761492011-01-13 15:46:58 -08002038static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
2039 unsigned long address,
2040 pte_t *pte)
2041{
2042 struct page *page;
2043 pte_t *_pte;
Bob Liu344aa352012-12-11 16:00:34 -08002044 int referenced = 0, none = 0;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002045 for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
2046 _pte++, address += PAGE_SIZE) {
2047 pte_t pteval = *_pte;
2048 if (pte_none(pteval)) {
2049 if (++none <= khugepaged_max_ptes_none)
2050 continue;
Bob Liu344aa352012-12-11 16:00:34 -08002051 else
Andrea Arcangeliba761492011-01-13 15:46:58 -08002052 goto out;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002053 }
Bob Liu344aa352012-12-11 16:00:34 -08002054 if (!pte_present(pteval) || !pte_write(pteval))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002055 goto out;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002056 page = vm_normal_page(vma, address, pteval);
Bob Liu344aa352012-12-11 16:00:34 -08002057 if (unlikely(!page))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002058 goto out;
Bob Liu344aa352012-12-11 16:00:34 -08002059
Andrea Arcangeliba761492011-01-13 15:46:58 -08002060 VM_BUG_ON(PageCompound(page));
2061 BUG_ON(!PageAnon(page));
2062 VM_BUG_ON(!PageSwapBacked(page));
2063
2064 /* cannot use mapcount: can't collapse if there's a gup pin */
Bob Liu344aa352012-12-11 16:00:34 -08002065 if (page_count(page) != 1)
Andrea Arcangeliba761492011-01-13 15:46:58 -08002066 goto out;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002067 /*
2068 * We can do it before isolate_lru_page because the
2069 * page can't be freed from under us. NOTE: PG_lock
2070 * is needed to serialize against split_huge_page
2071 * when invoked from the VM.
2072 */
Bob Liu344aa352012-12-11 16:00:34 -08002073 if (!trylock_page(page))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002074 goto out;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002075 /*
2076 * Isolate the page to avoid collapsing an hugepage
2077 * currently in use by the VM.
2078 */
2079 if (isolate_lru_page(page)) {
2080 unlock_page(page);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002081 goto out;
2082 }
2083 /* 0 stands for page_is_file_cache(page) == false */
2084 inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
2085 VM_BUG_ON(!PageLocked(page));
2086 VM_BUG_ON(PageLRU(page));
2087
2088 /* If there is no mapped pte young don't collapse the page */
Andrea Arcangeli8ee53822011-01-13 15:47:10 -08002089 if (pte_young(pteval) || PageReferenced(page) ||
2090 mmu_notifier_test_young(vma->vm_mm, address))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002091 referenced = 1;
2092 }
Bob Liu344aa352012-12-11 16:00:34 -08002093 if (likely(referenced))
2094 return 1;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002095out:
Bob Liu344aa352012-12-11 16:00:34 -08002096 release_pte_pages(pte, _pte);
2097 return 0;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002098}
2099
2100static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
2101 struct vm_area_struct *vma,
2102 unsigned long address,
2103 spinlock_t *ptl)
2104{
2105 pte_t *_pte;
2106 for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
2107 pte_t pteval = *_pte;
2108 struct page *src_page;
2109
2110 if (pte_none(pteval)) {
2111 clear_user_highpage(page, address);
2112 add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
2113 } else {
2114 src_page = pte_page(pteval);
2115 copy_user_highpage(page, src_page, address, vma);
2116 VM_BUG_ON(page_mapcount(src_page) != 1);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002117 release_pte_page(src_page);
2118 /*
2119 * ptl mostly unnecessary, but preempt has to
2120 * be disabled to update the per-cpu stats
2121 * inside page_remove_rmap().
2122 */
2123 spin_lock(ptl);
2124 /*
2125 * paravirt calls inside pte_clear here are
2126 * superfluous.
2127 */
2128 pte_clear(vma->vm_mm, address, _pte);
2129 page_remove_rmap(src_page);
2130 spin_unlock(ptl);
2131 free_page_and_swap_cache(src_page);
2132 }
2133
2134 address += PAGE_SIZE;
2135 page++;
2136 }
2137}
2138
Xiao Guangrong26234f32012-10-08 16:29:51 -07002139static void khugepaged_alloc_sleep(void)
2140{
2141 wait_event_freezable_timeout(khugepaged_wait, false,
2142 msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
2143}
2144
2145#ifdef CONFIG_NUMA
2146static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2147{
2148 if (IS_ERR(*hpage)) {
2149 if (!*wait)
2150 return false;
2151
2152 *wait = false;
Xiao Guangronge3b41262012-10-08 16:32:57 -07002153 *hpage = NULL;
Xiao Guangrong26234f32012-10-08 16:29:51 -07002154 khugepaged_alloc_sleep();
2155 } else if (*hpage) {
2156 put_page(*hpage);
2157 *hpage = NULL;
2158 }
2159
2160 return true;
2161}
2162
2163static struct page
2164*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2165 struct vm_area_struct *vma, unsigned long address,
2166 int node)
2167{
2168 VM_BUG_ON(*hpage);
2169 /*
2170 * Allocate the page while the vma is still valid and under
2171 * the mmap_sem read mode so there is no memory allocation
2172 * later when we take the mmap_sem in write mode. This is more
2173 * friendly behavior (OTOH it may actually hide bugs) to
2174 * filesystems in userland with daemons allocating memory in
2175 * the userland I/O paths. Allocating memory with the
2176 * mmap_sem in read mode is good idea also to allow greater
2177 * scalability.
2178 */
2179 *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address,
2180 node, __GFP_OTHER_NODE);
2181
2182 /*
2183 * After allocating the hugepage, release the mmap_sem read lock in
2184 * preparation for taking it in write mode.
2185 */
2186 up_read(&mm->mmap_sem);
2187 if (unlikely(!*hpage)) {
2188 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2189 *hpage = ERR_PTR(-ENOMEM);
2190 return NULL;
2191 }
2192
2193 count_vm_event(THP_COLLAPSE_ALLOC);
2194 return *hpage;
2195}
2196#else
2197static struct page *khugepaged_alloc_hugepage(bool *wait)
2198{
2199 struct page *hpage;
2200
2201 do {
2202 hpage = alloc_hugepage(khugepaged_defrag());
2203 if (!hpage) {
2204 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2205 if (!*wait)
2206 return NULL;
2207
2208 *wait = false;
2209 khugepaged_alloc_sleep();
2210 } else
2211 count_vm_event(THP_COLLAPSE_ALLOC);
2212 } while (unlikely(!hpage) && likely(khugepaged_enabled()));
2213
2214 return hpage;
2215}
2216
2217static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2218{
2219 if (!*hpage)
2220 *hpage = khugepaged_alloc_hugepage(wait);
2221
2222 if (unlikely(!*hpage))
2223 return false;
2224
2225 return true;
2226}
2227
2228static struct page
2229*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2230 struct vm_area_struct *vma, unsigned long address,
2231 int node)
2232{
2233 up_read(&mm->mmap_sem);
2234 VM_BUG_ON(!*hpage);
2235 return *hpage;
2236}
2237#endif
2238
Bob Liufa475e52012-12-11 16:00:39 -08002239static bool hugepage_vma_check(struct vm_area_struct *vma)
2240{
2241 if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
2242 (vma->vm_flags & VM_NOHUGEPAGE))
2243 return false;
2244
2245 if (!vma->anon_vma || vma->vm_ops)
2246 return false;
2247 if (is_vma_temporary_stack(vma))
2248 return false;
2249 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
2250 return true;
2251}
2252
Andrea Arcangeliba761492011-01-13 15:46:58 -08002253static void collapse_huge_page(struct mm_struct *mm,
Xiao Guangrong26234f32012-10-08 16:29:51 -07002254 unsigned long address,
2255 struct page **hpage,
2256 struct vm_area_struct *vma,
2257 int node)
Andrea Arcangeliba761492011-01-13 15:46:58 -08002258{
Andrea Arcangeliba761492011-01-13 15:46:58 -08002259 pmd_t *pmd, _pmd;
2260 pte_t *pte;
2261 pgtable_t pgtable;
2262 struct page *new_page;
2263 spinlock_t *ptl;
2264 int isolated;
2265 unsigned long hstart, hend;
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07002266 unsigned long mmun_start; /* For mmu_notifiers */
2267 unsigned long mmun_end; /* For mmu_notifiers */
Andrea Arcangeliba761492011-01-13 15:46:58 -08002268
2269 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
Andrea Arcangeli692e0b32011-05-24 17:12:14 -07002270
Xiao Guangrong26234f32012-10-08 16:29:51 -07002271 /* release the mmap_sem read lock. */
2272 new_page = khugepaged_alloc_page(hpage, mm, vma, address, node);
2273 if (!new_page)
Andrea Arcangelice83d212011-01-13 15:47:06 -08002274 return;
Andrea Arcangelice83d212011-01-13 15:47:06 -08002275
Xiao Guangrong420256ef2012-10-08 16:29:49 -07002276 if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)))
Andrea Arcangeli692e0b32011-05-24 17:12:14 -07002277 return;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002278
2279 /*
2280 * Prevent all access to pagetables with the exception of
2281 * gup_fast later hanlded by the ptep_clear_flush and the VM
2282 * handled by the anon_vma lock + PG_lock.
2283 */
2284 down_write(&mm->mmap_sem);
2285 if (unlikely(khugepaged_test_exit(mm)))
2286 goto out;
2287
2288 vma = find_vma(mm, address);
2289 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2290 hend = vma->vm_end & HPAGE_PMD_MASK;
2291 if (address < hstart || address + HPAGE_PMD_SIZE > hend)
2292 goto out;
Bob Liufa475e52012-12-11 16:00:39 -08002293 if (!hugepage_vma_check(vma))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002294 goto out;
Bob Liu62190492012-12-11 16:00:37 -08002295 pmd = mm_find_pmd(mm, address);
2296 if (!pmd)
Andrea Arcangeliba761492011-01-13 15:46:58 -08002297 goto out;
Bob Liu62190492012-12-11 16:00:37 -08002298 if (pmd_trans_huge(*pmd))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002299 goto out;
2300
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +00002301 anon_vma_lock_write(vma->anon_vma);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002302
2303 pte = pte_offset_map(pmd, address);
2304 ptl = pte_lockptr(mm, pmd);
2305
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07002306 mmun_start = address;
2307 mmun_end = address + HPAGE_PMD_SIZE;
2308 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002309 spin_lock(&mm->page_table_lock); /* probably unnecessary */
2310 /*
2311 * After this gup_fast can't run anymore. This also removes
2312 * any huge TLB entry from the CPU so we won't allow
2313 * huge and small TLB entries for the same virtual address
2314 * to avoid the risk of CPU bugs in that area.
2315 */
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07002316 _pmd = pmdp_clear_flush(vma, address, pmd);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002317 spin_unlock(&mm->page_table_lock);
Sagi Grimberg2ec74c32012-10-08 16:33:33 -07002318 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002319
2320 spin_lock(ptl);
2321 isolated = __collapse_huge_page_isolate(vma, address, pte);
2322 spin_unlock(ptl);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002323
2324 if (unlikely(!isolated)) {
Johannes Weiner453c7192011-01-20 14:44:18 -08002325 pte_unmap(pte);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002326 spin_lock(&mm->page_table_lock);
2327 BUG_ON(!pmd_none(*pmd));
Aneesh Kumar K.V7c342512013-05-24 15:55:21 -07002328 /*
2329 * We can only use set_pmd_at when establishing
2330 * hugepmds and never for establishing regular pmds that
2331 * points to regular pagetables. Use pmd_populate for that
2332 */
2333 pmd_populate(mm, pmd, pmd_pgtable(_pmd));
Andrea Arcangeliba761492011-01-13 15:46:58 -08002334 spin_unlock(&mm->page_table_lock);
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08002335 anon_vma_unlock_write(vma->anon_vma);
Andrea Arcangelice83d212011-01-13 15:47:06 -08002336 goto out;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002337 }
2338
2339 /*
2340 * All pages are isolated and locked so anon_vma rmap
2341 * can't run anymore.
2342 */
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08002343 anon_vma_unlock_write(vma->anon_vma);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002344
2345 __collapse_huge_page_copy(pte, new_page, vma, address, ptl);
Johannes Weiner453c7192011-01-20 14:44:18 -08002346 pte_unmap(pte);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002347 __SetPageUptodate(new_page);
2348 pgtable = pmd_pgtable(_pmd);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002349
Bob Liub3092b32012-12-11 16:00:41 -08002350 _pmd = mk_huge_pmd(new_page, vma);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002351
2352 /*
2353 * spin_lock() below is not the equivalent of smp_wmb(), so
2354 * this is needed to avoid the copy_huge_page writes to become
2355 * visible after the set_pmd_at() write.
2356 */
2357 smp_wmb();
2358
2359 spin_lock(&mm->page_table_lock);
2360 BUG_ON(!pmd_none(*pmd));
2361 page_add_new_anon_rmap(new_page, vma, address);
2362 set_pmd_at(mm, address, pmd, _pmd);
David Millerb113da62012-10-08 16:34:25 -07002363 update_mmu_cache_pmd(vma, address, pmd);
Gerald Schaefere3ebcf642012-10-08 16:30:07 -07002364 pgtable_trans_huge_deposit(mm, pgtable);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002365 spin_unlock(&mm->page_table_lock);
2366
2367 *hpage = NULL;
Xiao Guangrong420256ef2012-10-08 16:29:49 -07002368
Andrea Arcangeliba761492011-01-13 15:46:58 -08002369 khugepaged_pages_collapsed++;
Andrea Arcangelice83d212011-01-13 15:47:06 -08002370out_up_write:
Andrea Arcangeliba761492011-01-13 15:46:58 -08002371 up_write(&mm->mmap_sem);
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -08002372 return;
2373
Andrea Arcangelice83d212011-01-13 15:47:06 -08002374out:
KAMEZAWA Hiroyuki678ff892011-02-10 15:01:36 -08002375 mem_cgroup_uncharge_page(new_page);
Andrea Arcangelice83d212011-01-13 15:47:06 -08002376 goto out_up_write;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002377}
2378
2379static int khugepaged_scan_pmd(struct mm_struct *mm,
2380 struct vm_area_struct *vma,
2381 unsigned long address,
2382 struct page **hpage)
2383{
Andrea Arcangeliba761492011-01-13 15:46:58 -08002384 pmd_t *pmd;
2385 pte_t *pte, *_pte;
2386 int ret = 0, referenced = 0, none = 0;
2387 struct page *page;
2388 unsigned long _address;
2389 spinlock_t *ptl;
David Rientjes00ef2d22013-02-22 16:35:36 -08002390 int node = NUMA_NO_NODE;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002391
2392 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
2393
Bob Liu62190492012-12-11 16:00:37 -08002394 pmd = mm_find_pmd(mm, address);
2395 if (!pmd)
Andrea Arcangeliba761492011-01-13 15:46:58 -08002396 goto out;
Bob Liu62190492012-12-11 16:00:37 -08002397 if (pmd_trans_huge(*pmd))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002398 goto out;
2399
2400 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2401 for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
2402 _pte++, _address += PAGE_SIZE) {
2403 pte_t pteval = *_pte;
2404 if (pte_none(pteval)) {
2405 if (++none <= khugepaged_max_ptes_none)
2406 continue;
2407 else
2408 goto out_unmap;
2409 }
2410 if (!pte_present(pteval) || !pte_write(pteval))
2411 goto out_unmap;
2412 page = vm_normal_page(vma, _address, pteval);
2413 if (unlikely(!page))
2414 goto out_unmap;
Andi Kleen5c4b4be2011-03-04 17:36:32 -08002415 /*
2416 * Chose the node of the first page. This could
2417 * be more sophisticated and look at more pages,
2418 * but isn't for now.
2419 */
David Rientjes00ef2d22013-02-22 16:35:36 -08002420 if (node == NUMA_NO_NODE)
Andi Kleen5c4b4be2011-03-04 17:36:32 -08002421 node = page_to_nid(page);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002422 VM_BUG_ON(PageCompound(page));
2423 if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
2424 goto out_unmap;
2425 /* cannot use mapcount: can't collapse if there's a gup pin */
2426 if (page_count(page) != 1)
2427 goto out_unmap;
Andrea Arcangeli8ee53822011-01-13 15:47:10 -08002428 if (pte_young(pteval) || PageReferenced(page) ||
2429 mmu_notifier_test_young(vma->vm_mm, address))
Andrea Arcangeliba761492011-01-13 15:46:58 -08002430 referenced = 1;
2431 }
2432 if (referenced)
2433 ret = 1;
2434out_unmap:
2435 pte_unmap_unlock(pte, ptl);
Andrea Arcangelice83d212011-01-13 15:47:06 -08002436 if (ret)
2437 /* collapse_huge_page will return with the mmap_sem released */
Andi Kleen5c4b4be2011-03-04 17:36:32 -08002438 collapse_huge_page(mm, address, hpage, vma, node);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002439out:
2440 return ret;
2441}
2442
2443static void collect_mm_slot(struct mm_slot *mm_slot)
2444{
2445 struct mm_struct *mm = mm_slot->mm;
2446
Hugh Dickinsb9980cd2012-02-08 17:13:40 -08002447 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
Andrea Arcangeliba761492011-01-13 15:46:58 -08002448
2449 if (khugepaged_test_exit(mm)) {
2450 /* free mm_slot */
Sasha Levin43b5fbb2013-02-22 16:32:27 -08002451 hash_del(&mm_slot->hash);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002452 list_del(&mm_slot->mm_node);
2453
2454 /*
2455 * Not strictly needed because the mm exited already.
2456 *
2457 * clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
2458 */
2459
2460 /* khugepaged_mm_lock actually not necessary for the below */
2461 free_mm_slot(mm_slot);
2462 mmdrop(mm);
2463 }
2464}
2465
2466static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
2467 struct page **hpage)
H Hartley Sweeten2f1da642011-10-31 17:09:25 -07002468 __releases(&khugepaged_mm_lock)
2469 __acquires(&khugepaged_mm_lock)
Andrea Arcangeliba761492011-01-13 15:46:58 -08002470{
2471 struct mm_slot *mm_slot;
2472 struct mm_struct *mm;
2473 struct vm_area_struct *vma;
2474 int progress = 0;
2475
2476 VM_BUG_ON(!pages);
Hugh Dickinsb9980cd2012-02-08 17:13:40 -08002477 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
Andrea Arcangeliba761492011-01-13 15:46:58 -08002478
2479 if (khugepaged_scan.mm_slot)
2480 mm_slot = khugepaged_scan.mm_slot;
2481 else {
2482 mm_slot = list_entry(khugepaged_scan.mm_head.next,
2483 struct mm_slot, mm_node);
2484 khugepaged_scan.address = 0;
2485 khugepaged_scan.mm_slot = mm_slot;
2486 }
2487 spin_unlock(&khugepaged_mm_lock);
2488
2489 mm = mm_slot->mm;
2490 down_read(&mm->mmap_sem);
2491 if (unlikely(khugepaged_test_exit(mm)))
2492 vma = NULL;
2493 else
2494 vma = find_vma(mm, khugepaged_scan.address);
2495
2496 progress++;
2497 for (; vma; vma = vma->vm_next) {
2498 unsigned long hstart, hend;
2499
2500 cond_resched();
2501 if (unlikely(khugepaged_test_exit(mm))) {
2502 progress++;
2503 break;
2504 }
Bob Liufa475e52012-12-11 16:00:39 -08002505 if (!hugepage_vma_check(vma)) {
2506skip:
Andrea Arcangeliba761492011-01-13 15:46:58 -08002507 progress++;
2508 continue;
2509 }
Andrea Arcangeliba761492011-01-13 15:46:58 -08002510 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2511 hend = vma->vm_end & HPAGE_PMD_MASK;
Andrea Arcangelia7d6e4e2011-02-15 19:02:45 +01002512 if (hstart >= hend)
2513 goto skip;
2514 if (khugepaged_scan.address > hend)
2515 goto skip;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002516 if (khugepaged_scan.address < hstart)
2517 khugepaged_scan.address = hstart;
Andrea Arcangelia7d6e4e2011-02-15 19:02:45 +01002518 VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002519
2520 while (khugepaged_scan.address < hend) {
2521 int ret;
2522 cond_resched();
2523 if (unlikely(khugepaged_test_exit(mm)))
2524 goto breakouterloop;
2525
2526 VM_BUG_ON(khugepaged_scan.address < hstart ||
2527 khugepaged_scan.address + HPAGE_PMD_SIZE >
2528 hend);
2529 ret = khugepaged_scan_pmd(mm, vma,
2530 khugepaged_scan.address,
2531 hpage);
2532 /* move to next address */
2533 khugepaged_scan.address += HPAGE_PMD_SIZE;
2534 progress += HPAGE_PMD_NR;
2535 if (ret)
2536 /* we released mmap_sem so break loop */
2537 goto breakouterloop_mmap_sem;
2538 if (progress >= pages)
2539 goto breakouterloop;
2540 }
2541 }
2542breakouterloop:
2543 up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */
2544breakouterloop_mmap_sem:
2545
2546 spin_lock(&khugepaged_mm_lock);
Andrea Arcangelia7d6e4e2011-02-15 19:02:45 +01002547 VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002548 /*
2549 * Release the current mm_slot if this mm is about to die, or
2550 * if we scanned all vmas of this mm.
2551 */
2552 if (khugepaged_test_exit(mm) || !vma) {
2553 /*
2554 * Make sure that if mm_users is reaching zero while
2555 * khugepaged runs here, khugepaged_exit will find
2556 * mm_slot not pointing to the exiting mm.
2557 */
2558 if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
2559 khugepaged_scan.mm_slot = list_entry(
2560 mm_slot->mm_node.next,
2561 struct mm_slot, mm_node);
2562 khugepaged_scan.address = 0;
2563 } else {
2564 khugepaged_scan.mm_slot = NULL;
2565 khugepaged_full_scans++;
2566 }
2567
2568 collect_mm_slot(mm_slot);
2569 }
2570
2571 return progress;
2572}
2573
2574static int khugepaged_has_work(void)
2575{
2576 return !list_empty(&khugepaged_scan.mm_head) &&
2577 khugepaged_enabled();
2578}
2579
2580static int khugepaged_wait_event(void)
2581{
2582 return !list_empty(&khugepaged_scan.mm_head) ||
Xiao Guangrong2017c0b2012-10-08 16:29:44 -07002583 kthread_should_stop();
Andrea Arcangeliba761492011-01-13 15:46:58 -08002584}
2585
Xiao Guangrongd5169042012-10-08 16:29:48 -07002586static void khugepaged_do_scan(void)
2587{
2588 struct page *hpage = NULL;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002589 unsigned int progress = 0, pass_through_head = 0;
2590 unsigned int pages = khugepaged_pages_to_scan;
Xiao Guangrongd5169042012-10-08 16:29:48 -07002591 bool wait = true;
Andrea Arcangeliba761492011-01-13 15:46:58 -08002592
2593 barrier(); /* write khugepaged_pages_to_scan to local stack */
2594
2595 while (progress < pages) {
Xiao Guangrong26234f32012-10-08 16:29:51 -07002596 if (!khugepaged_prealloc_page(&hpage, &wait))
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -08002597 break;
Xiao Guangrong26234f32012-10-08 16:29:51 -07002598
Xiao Guangrong420256ef2012-10-08 16:29:49 -07002599 cond_resched();
Andrea Arcangeliba761492011-01-13 15:46:58 -08002600
Andrea Arcangeli878aee72011-01-13 15:47:10 -08002601 if (unlikely(kthread_should_stop() || freezing(current)))
2602 break;
2603
Andrea Arcangeliba761492011-01-13 15:46:58 -08002604 spin_lock(&khugepaged_mm_lock);
2605 if (!khugepaged_scan.mm_slot)
2606 pass_through_head++;
2607 if (khugepaged_has_work() &&
2608 pass_through_head < 2)
2609 progress += khugepaged_scan_mm_slot(pages - progress,
Xiao Guangrongd5169042012-10-08 16:29:48 -07002610 &hpage);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002611 else
2612 progress = pages;
2613 spin_unlock(&khugepaged_mm_lock);
2614 }
Andrea Arcangeliba761492011-01-13 15:46:58 -08002615
Xiao Guangrongd5169042012-10-08 16:29:48 -07002616 if (!IS_ERR_OR_NULL(hpage))
2617 put_page(hpage);
Andrea Arcangeli0bbbc0b2011-01-13 15:47:05 -08002618}
2619
Xiao Guangrong2017c0b2012-10-08 16:29:44 -07002620static void khugepaged_wait_work(void)
2621{
2622 try_to_freeze();
2623
2624 if (khugepaged_has_work()) {
2625 if (!khugepaged_scan_sleep_millisecs)
2626 return;
2627
2628 wait_event_freezable_timeout(khugepaged_wait,
2629 kthread_should_stop(),
2630 msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
2631 return;
2632 }
2633
2634 if (khugepaged_enabled())
2635 wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
2636}
2637
Andrea Arcangeliba761492011-01-13 15:46:58 -08002638static int khugepaged(void *none)
2639{
2640 struct mm_slot *mm_slot;
2641
Andrea Arcangeli878aee72011-01-13 15:47:10 -08002642 set_freezable();
Andrea Arcangeliba761492011-01-13 15:46:58 -08002643 set_user_nice(current, 19);
2644
Xiao Guangrongb7231782012-10-08 16:29:54 -07002645 while (!kthread_should_stop()) {
2646 khugepaged_do_scan();
2647 khugepaged_wait_work();
2648 }
Andrea Arcangeliba761492011-01-13 15:46:58 -08002649
2650 spin_lock(&khugepaged_mm_lock);
2651 mm_slot = khugepaged_scan.mm_slot;
2652 khugepaged_scan.mm_slot = NULL;
2653 if (mm_slot)
2654 collect_mm_slot(mm_slot);
2655 spin_unlock(&khugepaged_mm_lock);
Andrea Arcangeliba761492011-01-13 15:46:58 -08002656 return 0;
2657}
2658
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002659static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
2660 unsigned long haddr, pmd_t *pmd)
2661{
2662 struct mm_struct *mm = vma->vm_mm;
2663 pgtable_t pgtable;
2664 pmd_t _pmd;
2665 int i;
2666
2667 pmdp_clear_flush(vma, haddr, pmd);
2668 /* leave pmd empty until pte is filled */
2669
2670 pgtable = pgtable_trans_huge_withdraw(mm);
2671 pmd_populate(mm, &_pmd, pgtable);
2672
2673 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
2674 pte_t *pte, entry;
2675 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
2676 entry = pte_mkspecial(entry);
2677 pte = pte_offset_map(&_pmd, haddr);
2678 VM_BUG_ON(!pte_none(*pte));
2679 set_pte_at(mm, haddr, pte, entry);
2680 pte_unmap(pte);
2681 }
2682 smp_wmb(); /* make pte visible before pmd */
2683 pmd_populate(mm, pmd, pgtable);
Kirill A. Shutemov97ae1742012-12-12 13:51:06 -08002684 put_huge_zero_page();
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002685}
2686
Kirill A. Shutemove1803772012-12-12 13:50:59 -08002687void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
2688 pmd_t *pmd)
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08002689{
2690 struct page *page;
Kirill A. Shutemove1803772012-12-12 13:50:59 -08002691 struct mm_struct *mm = vma->vm_mm;
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002692 unsigned long haddr = address & HPAGE_PMD_MASK;
2693 unsigned long mmun_start; /* For mmu_notifiers */
2694 unsigned long mmun_end; /* For mmu_notifiers */
Kirill A. Shutemove1803772012-12-12 13:50:59 -08002695
2696 BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08002697
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002698 mmun_start = haddr;
2699 mmun_end = haddr + HPAGE_PMD_SIZE;
2700 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08002701 spin_lock(&mm->page_table_lock);
2702 if (unlikely(!pmd_trans_huge(*pmd))) {
2703 spin_unlock(&mm->page_table_lock);
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002704 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2705 return;
2706 }
2707 if (is_huge_zero_pmd(*pmd)) {
2708 __split_huge_zero_page_pmd(vma, haddr, pmd);
2709 spin_unlock(&mm->page_table_lock);
2710 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08002711 return;
2712 }
2713 page = pmd_page(*pmd);
2714 VM_BUG_ON(!page_count(page));
2715 get_page(page);
2716 spin_unlock(&mm->page_table_lock);
Kirill A. Shutemovc5a647d2012-12-12 13:51:00 -08002717 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -08002718
2719 split_huge_page(page);
2720
2721 put_page(page);
2722 BUG_ON(pmd_trans_huge(*pmd));
2723}
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08002724
Kirill A. Shutemove1803772012-12-12 13:50:59 -08002725void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
2726 pmd_t *pmd)
2727{
2728 struct vm_area_struct *vma;
2729
2730 vma = find_vma(mm, address);
2731 BUG_ON(vma == NULL);
2732 split_huge_page_pmd(vma, address, pmd);
2733}
2734
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08002735static void split_huge_page_address(struct mm_struct *mm,
2736 unsigned long address)
2737{
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08002738 pmd_t *pmd;
2739
2740 VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
2741
Bob Liu62190492012-12-11 16:00:37 -08002742 pmd = mm_find_pmd(mm, address);
2743 if (!pmd)
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08002744 return;
2745 /*
2746 * Caller holds the mmap_sem write mode, so a huge pmd cannot
2747 * materialize from under us.
2748 */
Kirill A. Shutemove1803772012-12-12 13:50:59 -08002749 split_huge_page_pmd_mm(mm, address, pmd);
Andrea Arcangeli94fcc582011-01-13 15:47:08 -08002750}
2751
2752void __vma_adjust_trans_huge(struct vm_area_struct *vma,
2753 unsigned long start,
2754 unsigned long end,
2755 long adjust_next)
2756{
2757 /*
2758 * If the new start address isn't hpage aligned and it could
2759 * previously contain an hugepage: check if we need to split
2760 * an huge pmd.
2761 */
2762 if (start & ~HPAGE_PMD_MASK &&
2763 (start & HPAGE_PMD_MASK) >= vma->vm_start &&
2764 (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2765 split_huge_page_address(vma->vm_mm, start);
2766
2767 /*
2768 * If the new end address isn't hpage aligned and it could
2769 * previously contain an hugepage: check if we need to split
2770 * an huge pmd.
2771 */
2772 if (end & ~HPAGE_PMD_MASK &&
2773 (end & HPAGE_PMD_MASK) >= vma->vm_start &&
2774 (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2775 split_huge_page_address(vma->vm_mm, end);
2776
2777 /*
2778 * If we're also updating the vma->vm_next->vm_start, if the new
2779 * vm_next->vm_start isn't page aligned and it could previously
2780 * contain an hugepage: check if we need to split an huge pmd.
2781 */
2782 if (adjust_next > 0) {
2783 struct vm_area_struct *next = vma->vm_next;
2784 unsigned long nstart = next->vm_start;
2785 nstart += adjust_next << PAGE_SHIFT;
2786 if (nstart & ~HPAGE_PMD_MASK &&
2787 (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
2788 (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
2789 split_huge_page_address(next->vm_mm, nstart);
2790 }
2791}