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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>
15#include <linux/shrinker.h>
16#include <linux/mm_inline.h>
17#include <linux/kthread.h>
18#include <linux/khugepaged.h>
19#include <linux/freezer.h>
20#include <linux/mman.h>
21#include <linux/pagemap.h>
22#include <linux/migrate.h>
23#include <linux/hashtable.h>
24
25#include <asm/tlb.h>
26#include <asm/pgalloc.h>
27#include "internal.h"
28
29
30
31
32
33
34
35
36unsigned long transparent_hugepage_flags __read_mostly =
37#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
38 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
39#endif
40#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
41 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
42#endif
43 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
44 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
45 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
46
47
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
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
60
61
62
63static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1;
64
65static int khugepaged(void *none);
66static int khugepaged_slab_init(void);
67
68#define MM_SLOTS_HASH_BITS 10
69static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
70
71static struct kmem_cache *mm_slot_cache __read_mostly;
72
73
74
75
76
77
78
79struct mm_slot {
80 struct hlist_node hash;
81 struct list_head mm_node;
82 struct mm_struct *mm;
83};
84
85
86
87
88
89
90
91
92
93struct khugepaged_scan {
94 struct list_head mm_head;
95 struct mm_slot *mm_slot;
96 unsigned long address;
97};
98static struct khugepaged_scan khugepaged_scan = {
99 .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
100};
101
102
103static int set_recommended_min_free_kbytes(void)
104{
105 struct zone *zone;
106 int nr_zones = 0;
107 unsigned long recommended_min;
108
109 if (!khugepaged_enabled())
110 return 0;
111
112 for_each_populated_zone(zone)
113 nr_zones++;
114
115
116 recommended_min = pageblock_nr_pages * nr_zones * 2;
117
118
119
120
121
122
123
124 recommended_min += pageblock_nr_pages * nr_zones *
125 MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
126
127
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
139static int start_khugepaged(void)
140{
141 int err = 0;
142 if (khugepaged_enabled()) {
143 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 }
152
153 if (!list_empty(&khugepaged_scan.mm_head))
154 wake_up_interruptible(&khugepaged_wait);
155
156 set_recommended_min_free_kbytes();
157 } else if (khugepaged_thread) {
158 kthread_stop(khugepaged_thread);
159 khugepaged_thread = NULL;
160 }
161
162 return err;
163}
164
165static atomic_t huge_zero_refcount;
166static struct page *huge_zero_page __read_mostly;
167
168static inline bool is_huge_zero_page(struct page *page)
169{
170 return ACCESS_ONCE(huge_zero_page) == page;
171}
172
173static inline bool is_huge_zero_pmd(pmd_t pmd)
174{
175 return is_huge_zero_page(pmd_page(pmd));
176}
177
178static struct page *get_huge_zero_page(void)
179{
180 struct page *zero_page;
181retry:
182 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
183 return ACCESS_ONCE(huge_zero_page);
184
185 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
186 HPAGE_PMD_ORDER);
187 if (!zero_page) {
188 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
189 return NULL;
190 }
191 count_vm_event(THP_ZERO_PAGE_ALLOC);
192 preempt_disable();
193 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
194 preempt_enable();
195 __free_page(zero_page);
196 goto retry;
197 }
198
199
200 atomic_set(&huge_zero_refcount, 2);
201 preempt_enable();
202 return ACCESS_ONCE(huge_zero_page);
203}
204
205static void put_huge_zero_page(void)
206{
207
208
209
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
219 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
220
221 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
222 struct page *zero_page = xchg(&huge_zero_page, NULL);
223 BUG_ON(zero_page == NULL);
224 __free_page(zero_page);
225 }
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
235#ifdef CONFIG_SYSFS
236
237static 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{
285 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) {
292 int err;
293
294 mutex_lock(&khugepaged_mutex);
295 err = start_khugepaged();
296 mutex_unlock(&khugepaged_mutex);
297
298 if (err)
299 ret = err;
300 }
301
302 return ret;
303}
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{
311 return sprintf(buf, "%d\n",
312 !!test_bit(flag, &transparent_hugepage_flags));
313}
314
315static 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{
320 unsigned long value;
321 int ret;
322
323 ret = kstrtoul(buf, 10, &value);
324 if (ret < 0)
325 return ret;
326 if (value > 1)
327 return -EINVAL;
328
329 if (value)
330 set_bit(flag, &transparent_hugepage_flags);
331 else
332 clear_bit(flag, &transparent_hugepage_flags);
333
334 return count;
335}
336
337
338
339
340
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
360static 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);
374#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
391
392static struct attribute *hugepage_attr[] = {
393 &enabled_attr.attr,
394 &defrag_attr.attr,
395 &use_zero_page_attr.attr,
396#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,
404};
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
522
523
524
525
526
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",
567};
568
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)) {
575 printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n");
576 return -ENOMEM;
577 }
578
579 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
580 if (err) {
581 printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
582 goto delete_obj;
583 }
584
585 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
586 if (err) {
587 printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
588 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}
615#endif
616
617static int __init hugepage_init(void)
618{
619 int err;
620 struct kobject *hugepage_kobj;
621
622 if (!has_transparent_hugepage()) {
623 transparent_hugepage_flags = 0;
624 return -EINVAL;
625 }
626
627 err = hugepage_init_sysfs(&hugepage_kobj);
628 if (err)
629 return err;
630
631 err = khugepaged_slab_init();
632 if (err)
633 goto out;
634
635 register_shrinker(&huge_zero_page_shrinker);
636
637
638
639
640
641
642 if (totalram_pages < (512 << (20 - PAGE_SHIFT)))
643 transparent_hugepage_flags = 0;
644
645 start_khugepaged();
646
647 return 0;
648out:
649 hugepage_exit_sysfs(hugepage_kobj);
650 return err;
651}
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
686pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
687{
688 if (likely(vma->vm_flags & VM_WRITE))
689 pmd = pmd_mkwrite(pmd);
690 return pmd;
691}
692
693static 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
702static 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{
707 pgtable_t pgtable;
708
709 VM_BUG_ON(!PageCompound(page));
710 pgtable = pte_alloc_one(mm, haddr);
711 if (unlikely(!pgtable))
712 return VM_FAULT_OOM;
713
714 clear_huge_page(page, haddr, HPAGE_PMD_NR);
715
716
717
718
719
720 __SetPageUptodate(page);
721
722 spin_lock(&mm->page_table_lock);
723 if (unlikely(!pmd_none(*pmd))) {
724 spin_unlock(&mm->page_table_lock);
725 mem_cgroup_uncharge_page(page);
726 put_page(page);
727 pte_free(mm, pgtable);
728 } else {
729 pmd_t entry;
730 entry = mk_huge_pmd(page, vma);
731 page_add_new_anon_rmap(page, vma, haddr);
732 pgtable_trans_huge_deposit(mm, pmd, pgtable);
733 set_pmd_at(mm, haddr, pmd, entry);
734 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
735 mm->nr_ptes++;
736 spin_unlock(&mm->page_table_lock);
737 }
738
739 return 0;
740}
741
742static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp)
743{
744 return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp;
745}
746
747static inline struct page *alloc_hugepage_vma(int defrag,
748 struct vm_area_struct *vma,
749 unsigned long haddr, int nd,
750 gfp_t extra_gfp)
751{
752 return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp),
753 HPAGE_PMD_ORDER, vma, haddr, nd);
754}
755
756#ifndef CONFIG_NUMA
757static inline struct page *alloc_hugepage(int defrag)
758{
759 return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
760 HPAGE_PMD_ORDER);
761}
762#endif
763
764static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
765 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
766 struct page *zero_page)
767{
768 pmd_t entry;
769 if (!pmd_none(*pmd))
770 return false;
771 entry = mk_pmd(zero_page, vma->vm_page_prot);
772 entry = pmd_wrprotect(entry);
773 entry = pmd_mkhuge(entry);
774 pgtable_trans_huge_deposit(mm, pmd, pgtable);
775 set_pmd_at(mm, haddr, pmd, entry);
776 mm->nr_ptes++;
777 return true;
778}
779
780int 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;
791 if (unlikely(khugepaged_enter(vma)))
792 return VM_FAULT_OOM;
793 if (!(flags & FAULT_FLAG_WRITE) &&
794 transparent_hugepage_use_zero_page()) {
795 pgtable_t pgtable;
796 struct page *zero_page;
797 bool set;
798 pgtable = pte_alloc_one(mm, haddr);
799 if (unlikely(!pgtable))
800 return VM_FAULT_OOM;
801 zero_page = get_huge_zero_page();
802 if (unlikely(!zero_page)) {
803 pte_free(mm, pgtable);
804 count_vm_event(THP_FAULT_FALLBACK);
805 goto out;
806 }
807 spin_lock(&mm->page_table_lock);
808 set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd,
809 zero_page);
810 spin_unlock(&mm->page_table_lock);
811 if (!set) {
812 pte_free(mm, pgtable);
813 put_huge_zero_page();
814 }
815 return 0;
816 }
817 page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
818 vma, haddr, numa_node_id(), 0);
819 if (unlikely(!page)) {
820 count_vm_event(THP_FAULT_FALLBACK);
821 goto out;
822 }
823 count_vm_event(THP_FAULT_ALLOC);
824 if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
825 put_page(page);
826 goto out;
827 }
828 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 }
834
835 return 0;
836 }
837out:
838
839
840
841
842
843 if (unlikely(pmd_none(*pmd)) &&
844 unlikely(__pte_alloc(mm, vma, pmd, address)))
845 return VM_FAULT_OOM;
846
847 if (unlikely(pmd_trans_huge(*pmd)))
848 return 0;
849
850
851
852
853
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 }
882
883
884
885
886
887 if (is_huge_zero_pmd(pmd)) {
888 struct page *zero_page;
889 bool set;
890
891
892
893
894
895 zero_page = get_huge_zero_page();
896 set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd,
897 zero_page);
898 BUG_ON(!set);
899 ret = 0;
900 goto out_unlock;
901 }
902 if (unlikely(pmd_trans_splitting(pmd))) {
903
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);
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 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
920 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
921 dst_mm->nr_ptes++;
922
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
931void 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
953static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
954 struct vm_area_struct *vma, unsigned long address,
955 pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr)
956{
957 pgtable_t pgtable;
958 pmd_t _pmd;
959 struct page *page;
960 int i, ret = 0;
961 unsigned long mmun_start;
962 unsigned long mmun_end;
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);
984 if (unlikely(!pmd_same(*pmd, orig_pmd)))
985 goto out_free_page;
986
987 pmdp_clear_flush(vma, haddr, pmd);
988
989
990 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
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();
1009 pmd_populate(mm, pmd, pgtable);
1010 spin_unlock(&mm->page_table_lock);
1011 put_huge_zero_page();
1012 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;
1019out_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;
1025}
1026
1027static 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;
1038 unsigned long mmun_start;
1039 unsigned long mmun_end;
1040
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++) {
1049 pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE |
1050 __GFP_OTHER_NODE,
1051 vma, address, page_to_nid(page));
1052 if (unlikely(!pages[i] ||
1053 mem_cgroup_newpage_charge(pages[i], mm,
1054 GFP_KERNEL))) {
1055 if (pages[i])
1056 put_page(pages[i]);
1057 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();
1063 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,
1071 haddr + PAGE_SIZE * i, vma);
1072 __SetPageUptodate(pages[i]);
1073 cond_resched();
1074 }
1075
1076 mmun_start = haddr;
1077 mmun_end = haddr + HPAGE_PMD_SIZE;
1078 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1079
1080 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
1085 pmdp_clear_flush(vma, haddr, pmd);
1086
1087
1088 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1089 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
1103 smp_wmb();
1104 pmd_populate(mm, pmd, pgtable);
1105 page_remove_rmap(page);
1106 spin_unlock(&mm->page_table_lock);
1107
1108 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1109
1110 ret |= VM_FAULT_WRITE;
1111 put_page(page);
1112
1113out:
1114 return ret;
1115
1116out_free_pages:
1117 spin_unlock(&mm->page_table_lock);
1118 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1119 mem_cgroup_uncharge_start();
1120 for (i = 0; i < HPAGE_PMD_NR; i++) {
1121 mem_cgroup_uncharge_page(pages[i]);
1122 put_page(pages[i]);
1123 }
1124 mem_cgroup_uncharge_end();
1125 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;
1133 struct page *page = NULL, *new_page;
1134 unsigned long haddr;
1135 unsigned long mmun_start;
1136 unsigned long mmun_end;
1137
1138 VM_BUG_ON(!vma->anon_vma);
1139 haddr = address & HPAGE_PMD_MASK;
1140 if (is_huge_zero_pmd(orig_pmd))
1141 goto alloc;
1142 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));
1148 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))
1153 update_mmu_cache_pmd(vma, address, pmd);
1154 ret |= VM_FAULT_WRITE;
1155 goto out_unlock;
1156 }
1157 get_page(page);
1158 spin_unlock(&mm->page_table_lock);
1159alloc:
1160 if (transparent_hugepage_enabled(vma) &&
1161 !transparent_hugepage_debug_cow())
1162 new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
1163 vma, haddr, numa_node_id(), 0);
1164 else
1165 new_page = NULL;
1166
1167 if (unlikely(!new_page)) {
1168 count_vm_event(THP_FAULT_FALLBACK);
1169 if (is_huge_zero_pmd(orig_pmd)) {
1170 ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
1171 address, pmd, orig_pmd, haddr);
1172 } 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 }
1179 goto out;
1180 }
1181 count_vm_event(THP_FAULT_ALLOC);
1182
1183 if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
1184 put_page(new_page);
1185 if (page) {
1186 split_huge_page(page);
1187 put_page(page);
1188 }
1189 ret |= VM_FAULT_OOM;
1190 goto out;
1191 }
1192
1193 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);
1197 __SetPageUptodate(new_page);
1198
1199 mmun_start = haddr;
1200 mmun_end = haddr + HPAGE_PMD_SIZE;
1201 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1202
1203 spin_lock(&mm->page_table_lock);
1204 if (page)
1205 put_page(page);
1206 if (unlikely(!pmd_same(*pmd, orig_pmd))) {
1207 spin_unlock(&mm->page_table_lock);
1208 mem_cgroup_uncharge_page(new_page);
1209 put_page(new_page);
1210 goto out_mn;
1211 } else {
1212 pmd_t entry;
1213 entry = mk_huge_pmd(new_page, vma);
1214 pmdp_clear_flush(vma, haddr, pmd);
1215 page_add_new_anon_rmap(new_page, vma, haddr);
1216 set_pmd_at(mm, haddr, pmd, entry);
1217 update_mmu_cache_pmd(vma, address, pmd);
1218 if (is_huge_zero_pmd(orig_pmd)) {
1219 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
1220 put_huge_zero_page();
1221 } else {
1222 VM_BUG_ON(!PageHead(page));
1223 page_remove_rmap(page);
1224 put_page(page);
1225 }
1226 ret |= VM_FAULT_WRITE;
1227 }
1228 spin_unlock(&mm->page_table_lock);
1229out_mn:
1230 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1231out:
1232 return ret;
1233out_unlock:
1234 spin_unlock(&mm->page_table_lock);
1235 return ret;
1236}
1237
1238struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
1239 unsigned long addr,
1240 pmd_t *pmd,
1241 unsigned int flags)
1242{
1243 struct mm_struct *mm = vma->vm_mm;
1244 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
1251
1252 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1253 return ERR_PTR(-EFAULT);
1254
1255 page = pmd_page(*pmd);
1256 VM_BUG_ON(!PageHead(page));
1257 if (flags & FOLL_TOUCH) {
1258 pmd_t _pmd;
1259
1260
1261
1262
1263
1264
1265
1266
1267 _pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
1268 if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
1269 pmd, _pmd, 1))
1270 update_mmu_cache_pmd(vma, addr, pmd);
1271 }
1272 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1273 if (page->mapping && trylock_page(page)) {
1274 lru_add_drain();
1275 if (page->mapping)
1276 mlock_vma_page(page);
1277 unlock_page(page);
1278 }
1279 }
1280 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1281 VM_BUG_ON(!PageCompound(page));
1282 if (flags & FOLL_GET)
1283 get_page_foll(page);
1284
1285out:
1286 return page;
1287}
1288
1289
1290int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
1291 unsigned long addr, pmd_t pmd, pmd_t *pmdp)
1292{
1293 struct page *page;
1294 unsigned long haddr = addr & HPAGE_PMD_MASK;
1295 int target_nid;
1296 int current_nid = -1;
1297 bool migrated;
1298
1299 spin_lock(&mm->page_table_lock);
1300 if (unlikely(!pmd_same(pmd, *pmdp)))
1301 goto out_unlock;
1302
1303 page = pmd_page(pmd);
1304 get_page(page);
1305 current_nid = page_to_nid(page);
1306 count_vm_numa_event(NUMA_HINT_FAULTS);
1307 if (current_nid == numa_node_id())
1308 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
1309
1310 target_nid = mpol_misplaced(page, vma, haddr);
1311 if (target_nid == -1) {
1312 put_page(page);
1313 goto clear_pmdnuma;
1314 }
1315
1316
1317 spin_unlock(&mm->page_table_lock);
1318 lock_page(page);
1319
1320
1321 spin_lock(&mm->page_table_lock);
1322 if (unlikely(!pmd_same(pmd, *pmdp))) {
1323 unlock_page(page);
1324 put_page(page);
1325 goto out_unlock;
1326 }
1327 spin_unlock(&mm->page_table_lock);
1328
1329
1330 migrated = migrate_misplaced_transhuge_page(mm, vma,
1331 pmdp, pmd, addr, page, target_nid);
1332 if (!migrated)
1333 goto check_same;
1334
1335 task_numa_fault(target_nid, HPAGE_PMD_NR, true);
1336 return 0;
1337
1338check_same:
1339 spin_lock(&mm->page_table_lock);
1340 if (unlikely(!pmd_same(pmd, *pmdp)))
1341 goto out_unlock;
1342clear_pmdnuma:
1343 pmd = pmd_mknonnuma(pmd);
1344 set_pmd_at(mm, haddr, pmdp, pmd);
1345 VM_BUG_ON(pmd_numa(*pmdp));
1346 update_mmu_cache_pmd(vma, addr, pmdp);
1347out_unlock:
1348 spin_unlock(&mm->page_table_lock);
1349 if (current_nid != -1)
1350 task_numa_fault(current_nid, HPAGE_PMD_NR, false);
1351 return 0;
1352}
1353
1354int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1355 pmd_t *pmd, unsigned long addr)
1356{
1357 int ret = 0;
1358
1359 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1360 struct page *page;
1361 pgtable_t pgtable;
1362 pmd_t orig_pmd;
1363
1364
1365
1366
1367
1368
1369 orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
1370 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1371 pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
1372 if (is_huge_zero_pmd(orig_pmd)) {
1373 tlb->mm->nr_ptes--;
1374 spin_unlock(&tlb->mm->page_table_lock);
1375 put_huge_zero_page();
1376 } else {
1377 page = pmd_page(orig_pmd);
1378 page_remove_rmap(page);
1379 VM_BUG_ON(page_mapcount(page) < 0);
1380 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1381 VM_BUG_ON(!PageHead(page));
1382 tlb->mm->nr_ptes--;
1383 spin_unlock(&tlb->mm->page_table_lock);
1384 tlb_remove_page(tlb, page);
1385 }
1386 pte_free(tlb->mm, pgtable);
1387 ret = 1;
1388 }
1389 return ret;
1390}
1391
1392int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1393 unsigned long addr, unsigned long end,
1394 unsigned char *vec)
1395{
1396 int ret = 0;
1397
1398 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1399
1400
1401
1402
1403 spin_unlock(&vma->vm_mm->page_table_lock);
1404 memset(vec, 1, (end - addr) >> PAGE_SHIFT);
1405 ret = 1;
1406 }
1407
1408 return ret;
1409}
1410
1411int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
1412 unsigned long old_addr,
1413 unsigned long new_addr, unsigned long old_end,
1414 pmd_t *old_pmd, pmd_t *new_pmd)
1415{
1416 int ret = 0;
1417 pmd_t pmd;
1418
1419 struct mm_struct *mm = vma->vm_mm;
1420
1421 if ((old_addr & ~HPAGE_PMD_MASK) ||
1422 (new_addr & ~HPAGE_PMD_MASK) ||
1423 old_end - old_addr < HPAGE_PMD_SIZE ||
1424 (new_vma->vm_flags & VM_NOHUGEPAGE))
1425 goto out;
1426
1427
1428
1429
1430
1431 if (WARN_ON(!pmd_none(*new_pmd))) {
1432 VM_BUG_ON(pmd_trans_huge(*new_pmd));
1433 goto out;
1434 }
1435
1436 ret = __pmd_trans_huge_lock(old_pmd, vma);
1437 if (ret == 1) {
1438 pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
1439 VM_BUG_ON(!pmd_none(*new_pmd));
1440 set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
1441 spin_unlock(&mm->page_table_lock);
1442 }
1443out:
1444 return ret;
1445}
1446
1447int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1448 unsigned long addr, pgprot_t newprot, int prot_numa)
1449{
1450 struct mm_struct *mm = vma->vm_mm;
1451 int ret = 0;
1452
1453 if (__pmd_trans_huge_lock(pmd, vma) == 1) {
1454 pmd_t entry;
1455 entry = pmdp_get_and_clear(mm, addr, pmd);
1456 if (!prot_numa) {
1457 entry = pmd_modify(entry, newprot);
1458 BUG_ON(pmd_write(entry));
1459 } else {
1460 struct page *page = pmd_page(*pmd);
1461
1462
1463 if (page_mapcount(page) == 1 &&
1464 !pmd_numa(*pmd)) {
1465 entry = pmd_mknuma(entry);
1466 }
1467 }
1468 set_pmd_at(mm, addr, pmd, entry);
1469 spin_unlock(&vma->vm_mm->page_table_lock);
1470 ret = 1;
1471 }
1472
1473 return ret;
1474}
1475
1476
1477
1478
1479
1480
1481
1482
1483int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
1484{
1485 spin_lock(&vma->vm_mm->page_table_lock);
1486 if (likely(pmd_trans_huge(*pmd))) {
1487 if (unlikely(pmd_trans_splitting(*pmd))) {
1488 spin_unlock(&vma->vm_mm->page_table_lock);
1489 wait_split_huge_page(vma->anon_vma, pmd);
1490 return -1;
1491 } else {
1492
1493
1494 return 1;
1495 }
1496 }
1497 spin_unlock(&vma->vm_mm->page_table_lock);
1498 return 0;
1499}
1500
1501pmd_t *page_check_address_pmd(struct page *page,
1502 struct mm_struct *mm,
1503 unsigned long address,
1504 enum page_check_address_pmd_flag flag)
1505{
1506 pmd_t *pmd, *ret = NULL;
1507
1508 if (address & ~HPAGE_PMD_MASK)
1509 goto out;
1510
1511 pmd = mm_find_pmd(mm, address);
1512 if (!pmd)
1513 goto out;
1514 if (pmd_none(*pmd))
1515 goto out;
1516 if (pmd_page(*pmd) != page)
1517 goto out;
1518
1519
1520
1521
1522
1523
1524
1525 if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG &&
1526 pmd_trans_splitting(*pmd))
1527 goto out;
1528 if (pmd_trans_huge(*pmd)) {
1529 VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG &&
1530 !pmd_trans_splitting(*pmd));
1531 ret = pmd;
1532 }
1533out:
1534 return ret;
1535}
1536
1537static int __split_huge_page_splitting(struct page *page,
1538 struct vm_area_struct *vma,
1539 unsigned long address)
1540{
1541 struct mm_struct *mm = vma->vm_mm;
1542 pmd_t *pmd;
1543 int ret = 0;
1544
1545 const unsigned long mmun_start = address;
1546 const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
1547
1548 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1549 spin_lock(&mm->page_table_lock);
1550 pmd = page_check_address_pmd(page, mm, address,
1551 PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG);
1552 if (pmd) {
1553
1554
1555
1556
1557
1558
1559
1560 pmdp_splitting_flush(vma, address, pmd);
1561 ret = 1;
1562 }
1563 spin_unlock(&mm->page_table_lock);
1564 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1565
1566 return ret;
1567}
1568
1569static void __split_huge_page_refcount(struct page *page,
1570 struct list_head *list)
1571{
1572 int i;
1573 struct zone *zone = page_zone(page);
1574 struct lruvec *lruvec;
1575 int tail_count = 0;
1576
1577
1578 spin_lock_irq(&zone->lru_lock);
1579 lruvec = mem_cgroup_page_lruvec(page, zone);
1580
1581 compound_lock(page);
1582
1583 mem_cgroup_split_huge_fixup(page);
1584
1585 for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
1586 struct page *page_tail = page + i;
1587
1588
1589 BUG_ON(page_mapcount(page_tail) < 0);
1590 tail_count += page_mapcount(page_tail);
1591
1592 BUG_ON(tail_count < 0);
1593 BUG_ON(atomic_read(&page_tail->_count) != 0);
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607 atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1,
1608 &page_tail->_count);
1609
1610
1611 smp_mb();
1612
1613
1614
1615
1616
1617
1618 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON;
1619 page_tail->flags |= (page->flags &
1620 ((1L << PG_referenced) |
1621 (1L << PG_swapbacked) |
1622 (1L << PG_mlocked) |
1623 (1L << PG_uptodate) |
1624 (1L << PG_active) |
1625 (1L << PG_unevictable)));
1626 page_tail->flags |= (1L << PG_dirty);
1627
1628
1629 smp_wmb();
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645 page_tail->_mapcount = page->_mapcount;
1646
1647 BUG_ON(page_tail->mapping);
1648 page_tail->mapping = page->mapping;
1649
1650 page_tail->index = page->index + i;
1651 page_nid_xchg_last(page_tail, page_nid_last(page));
1652
1653 BUG_ON(!PageAnon(page_tail));
1654 BUG_ON(!PageUptodate(page_tail));
1655 BUG_ON(!PageDirty(page_tail));
1656 BUG_ON(!PageSwapBacked(page_tail));
1657
1658 lru_add_page_tail(page, page_tail, lruvec, list);
1659 }
1660 atomic_sub(tail_count, &page->_count);
1661 BUG_ON(atomic_read(&page->_count) <= 0);
1662
1663 __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1);
1664 __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR);
1665
1666 ClearPageCompound(page);
1667 compound_unlock(page);
1668 spin_unlock_irq(&zone->lru_lock);
1669
1670 for (i = 1; i < HPAGE_PMD_NR; i++) {
1671 struct page *page_tail = page + i;
1672 BUG_ON(page_count(page_tail) <= 0);
1673
1674
1675
1676
1677
1678
1679
1680 put_page(page_tail);
1681 }
1682
1683
1684
1685
1686
1687 BUG_ON(page_count(page) <= 0);
1688}
1689
1690static int __split_huge_page_map(struct page *page,
1691 struct vm_area_struct *vma,
1692 unsigned long address)
1693{
1694 struct mm_struct *mm = vma->vm_mm;
1695 pmd_t *pmd, _pmd;
1696 int ret = 0, i;
1697 pgtable_t pgtable;
1698 unsigned long haddr;
1699
1700 spin_lock(&mm->page_table_lock);
1701 pmd = page_check_address_pmd(page, mm, address,
1702 PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
1703 if (pmd) {
1704 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1705 pmd_populate(mm, &_pmd, pgtable);
1706
1707 haddr = address;
1708 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1709 pte_t *pte, entry;
1710 BUG_ON(PageCompound(page+i));
1711 entry = mk_pte(page + i, vma->vm_page_prot);
1712 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1713 if (!pmd_write(*pmd))
1714 entry = pte_wrprotect(entry);
1715 else
1716 BUG_ON(page_mapcount(page) != 1);
1717 if (!pmd_young(*pmd))
1718 entry = pte_mkold(entry);
1719 if (pmd_numa(*pmd))
1720 entry = pte_mknuma(entry);
1721 pte = pte_offset_map(&_pmd, haddr);
1722 BUG_ON(!pte_none(*pte));
1723 set_pte_at(mm, haddr, pte, entry);
1724 pte_unmap(pte);
1725 }
1726
1727 smp_wmb();
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754 pmdp_invalidate(vma, address, pmd);
1755 pmd_populate(mm, pmd, pgtable);
1756 ret = 1;
1757 }
1758 spin_unlock(&mm->page_table_lock);
1759
1760 return ret;
1761}
1762
1763
1764static void __split_huge_page(struct page *page,
1765 struct anon_vma *anon_vma,
1766 struct list_head *list)
1767{
1768 int mapcount, mapcount2;
1769 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1770 struct anon_vma_chain *avc;
1771
1772 BUG_ON(!PageHead(page));
1773 BUG_ON(PageTail(page));
1774
1775 mapcount = 0;
1776 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1777 struct vm_area_struct *vma = avc->vma;
1778 unsigned long addr = vma_address(page, vma);
1779 BUG_ON(is_vma_temporary_stack(vma));
1780 mapcount += __split_huge_page_splitting(page, vma, addr);
1781 }
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792 if (mapcount != page_mapcount(page))
1793 printk(KERN_ERR "mapcount %d page_mapcount %d\n",
1794 mapcount, page_mapcount(page));
1795 BUG_ON(mapcount != page_mapcount(page));
1796
1797 __split_huge_page_refcount(page, list);
1798
1799 mapcount2 = 0;
1800 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1801 struct vm_area_struct *vma = avc->vma;
1802 unsigned long addr = vma_address(page, vma);
1803 BUG_ON(is_vma_temporary_stack(vma));
1804 mapcount2 += __split_huge_page_map(page, vma, addr);
1805 }
1806 if (mapcount != mapcount2)
1807 printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n",
1808 mapcount, mapcount2, page_mapcount(page));
1809 BUG_ON(mapcount != mapcount2);
1810}
1811
1812
1813
1814
1815
1816
1817
1818
1819int split_huge_page_to_list(struct page *page, struct list_head *list)
1820{
1821 struct anon_vma *anon_vma;
1822 int ret = 1;
1823
1824 BUG_ON(is_huge_zero_page(page));
1825 BUG_ON(!PageAnon(page));
1826
1827
1828
1829
1830
1831
1832
1833
1834 anon_vma = page_get_anon_vma(page);
1835 if (!anon_vma)
1836 goto out;
1837 anon_vma_lock_write(anon_vma);
1838
1839 ret = 0;
1840 if (!PageCompound(page))
1841 goto out_unlock;
1842
1843 BUG_ON(!PageSwapBacked(page));
1844 __split_huge_page(page, anon_vma, list);
1845 count_vm_event(THP_SPLIT);
1846
1847 BUG_ON(PageCompound(page));
1848out_unlock:
1849 anon_vma_unlock_write(anon_vma);
1850 put_anon_vma(anon_vma);
1851out:
1852 return ret;
1853}
1854
1855#define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE)
1856
1857int hugepage_madvise(struct vm_area_struct *vma,
1858 unsigned long *vm_flags, int advice)
1859{
1860 struct mm_struct *mm = vma->vm_mm;
1861
1862 switch (advice) {
1863 case MADV_HUGEPAGE:
1864
1865
1866
1867 if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
1868 return -EINVAL;
1869 if (mm->def_flags & VM_NOHUGEPAGE)
1870 return -EINVAL;
1871 *vm_flags &= ~VM_NOHUGEPAGE;
1872 *vm_flags |= VM_HUGEPAGE;
1873
1874
1875
1876
1877
1878 if (unlikely(khugepaged_enter_vma_merge(vma)))
1879 return -ENOMEM;
1880 break;
1881 case MADV_NOHUGEPAGE:
1882
1883
1884
1885 if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP))
1886 return -EINVAL;
1887 *vm_flags &= ~VM_HUGEPAGE;
1888 *vm_flags |= VM_NOHUGEPAGE;
1889
1890
1891
1892
1893
1894 break;
1895 }
1896
1897 return 0;
1898}
1899
1900static int __init khugepaged_slab_init(void)
1901{
1902 mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
1903 sizeof(struct mm_slot),
1904 __alignof__(struct mm_slot), 0, NULL);
1905 if (!mm_slot_cache)
1906 return -ENOMEM;
1907
1908 return 0;
1909}
1910
1911static inline struct mm_slot *alloc_mm_slot(void)
1912{
1913 if (!mm_slot_cache)
1914 return NULL;
1915 return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
1916}
1917
1918static inline void free_mm_slot(struct mm_slot *mm_slot)
1919{
1920 kmem_cache_free(mm_slot_cache, mm_slot);
1921}
1922
1923static struct mm_slot *get_mm_slot(struct mm_struct *mm)
1924{
1925 struct mm_slot *mm_slot;
1926
1927 hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
1928 if (mm == mm_slot->mm)
1929 return mm_slot;
1930
1931 return NULL;
1932}
1933
1934static void insert_to_mm_slots_hash(struct mm_struct *mm,
1935 struct mm_slot *mm_slot)
1936{
1937 mm_slot->mm = mm;
1938 hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
1939}
1940
1941static inline int khugepaged_test_exit(struct mm_struct *mm)
1942{
1943 return atomic_read(&mm->mm_users) == 0;
1944}
1945
1946int __khugepaged_enter(struct mm_struct *mm)
1947{
1948 struct mm_slot *mm_slot;
1949 int wakeup;
1950
1951 mm_slot = alloc_mm_slot();
1952 if (!mm_slot)
1953 return -ENOMEM;
1954
1955
1956 VM_BUG_ON(khugepaged_test_exit(mm));
1957 if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
1958 free_mm_slot(mm_slot);
1959 return 0;
1960 }
1961
1962 spin_lock(&khugepaged_mm_lock);
1963 insert_to_mm_slots_hash(mm, mm_slot);
1964
1965
1966
1967
1968 wakeup = list_empty(&khugepaged_scan.mm_head);
1969 list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
1970 spin_unlock(&khugepaged_mm_lock);
1971
1972 atomic_inc(&mm->mm_count);
1973 if (wakeup)
1974 wake_up_interruptible(&khugepaged_wait);
1975
1976 return 0;
1977}
1978
1979int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
1980{
1981 unsigned long hstart, hend;
1982 if (!vma->anon_vma)
1983
1984
1985
1986
1987 return 0;
1988 if (vma->vm_ops)
1989
1990 return 0;
1991 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
1992 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
1993 hend = vma->vm_end & HPAGE_PMD_MASK;
1994 if (hstart < hend)
1995 return khugepaged_enter(vma);
1996 return 0;
1997}
1998
1999void __khugepaged_exit(struct mm_struct *mm)
2000{
2001 struct mm_slot *mm_slot;
2002 int free = 0;
2003
2004 spin_lock(&khugepaged_mm_lock);
2005 mm_slot = get_mm_slot(mm);
2006 if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
2007 hash_del(&mm_slot->hash);
2008 list_del(&mm_slot->mm_node);
2009 free = 1;
2010 }
2011 spin_unlock(&khugepaged_mm_lock);
2012
2013 if (free) {
2014 clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
2015 free_mm_slot(mm_slot);
2016 mmdrop(mm);
2017 } else if (mm_slot) {
2018
2019
2020
2021
2022
2023
2024
2025
2026 down_write(&mm->mmap_sem);
2027 up_write(&mm->mmap_sem);
2028 }
2029}
2030
2031static void release_pte_page(struct page *page)
2032{
2033
2034 dec_zone_page_state(page, NR_ISOLATED_ANON + 0);
2035 unlock_page(page);
2036 putback_lru_page(page);
2037}
2038
2039static void release_pte_pages(pte_t *pte, pte_t *_pte)
2040{
2041 while (--_pte >= pte) {
2042 pte_t pteval = *_pte;
2043 if (!pte_none(pteval))
2044 release_pte_page(pte_page(pteval));
2045 }
2046}
2047
2048static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
2049 unsigned long address,
2050 pte_t *pte)
2051{
2052 struct page *page;
2053 pte_t *_pte;
2054 int referenced = 0, none = 0;
2055 for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
2056 _pte++, address += PAGE_SIZE) {
2057 pte_t pteval = *_pte;
2058 if (pte_none(pteval)) {
2059 if (++none <= khugepaged_max_ptes_none)
2060 continue;
2061 else
2062 goto out;
2063 }
2064 if (!pte_present(pteval) || !pte_write(pteval))
2065 goto out;
2066 page = vm_normal_page(vma, address, pteval);
2067 if (unlikely(!page))
2068 goto out;
2069
2070 VM_BUG_ON(PageCompound(page));
2071 BUG_ON(!PageAnon(page));
2072 VM_BUG_ON(!PageSwapBacked(page));
2073
2074
2075 if (page_count(page) != 1)
2076 goto out;
2077
2078
2079
2080
2081
2082
2083 if (!trylock_page(page))
2084 goto out;
2085
2086
2087
2088
2089 if (isolate_lru_page(page)) {
2090 unlock_page(page);
2091 goto out;
2092 }
2093
2094 inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
2095 VM_BUG_ON(!PageLocked(page));
2096 VM_BUG_ON(PageLRU(page));
2097
2098
2099 if (pte_young(pteval) || PageReferenced(page) ||
2100 mmu_notifier_test_young(vma->vm_mm, address))
2101 referenced = 1;
2102 }
2103 if (likely(referenced))
2104 return 1;
2105out:
2106 release_pte_pages(pte, _pte);
2107 return 0;
2108}
2109
2110static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
2111 struct vm_area_struct *vma,
2112 unsigned long address,
2113 spinlock_t *ptl)
2114{
2115 pte_t *_pte;
2116 for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
2117 pte_t pteval = *_pte;
2118 struct page *src_page;
2119
2120 if (pte_none(pteval)) {
2121 clear_user_highpage(page, address);
2122 add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
2123 } else {
2124 src_page = pte_page(pteval);
2125 copy_user_highpage(page, src_page, address, vma);
2126 VM_BUG_ON(page_mapcount(src_page) != 1);
2127 release_pte_page(src_page);
2128
2129
2130
2131
2132
2133 spin_lock(ptl);
2134
2135
2136
2137
2138 pte_clear(vma->vm_mm, address, _pte);
2139 page_remove_rmap(src_page);
2140 spin_unlock(ptl);
2141 free_page_and_swap_cache(src_page);
2142 }
2143
2144 address += PAGE_SIZE;
2145 page++;
2146 }
2147}
2148
2149static void khugepaged_alloc_sleep(void)
2150{
2151 wait_event_freezable_timeout(khugepaged_wait, false,
2152 msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
2153}
2154
2155#ifdef CONFIG_NUMA
2156static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2157{
2158 if (IS_ERR(*hpage)) {
2159 if (!*wait)
2160 return false;
2161
2162 *wait = false;
2163 *hpage = NULL;
2164 khugepaged_alloc_sleep();
2165 } else if (*hpage) {
2166 put_page(*hpage);
2167 *hpage = NULL;
2168 }
2169
2170 return true;
2171}
2172
2173static struct page
2174*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2175 struct vm_area_struct *vma, unsigned long address,
2176 int node)
2177{
2178 VM_BUG_ON(*hpage);
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189 *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address,
2190 node, __GFP_OTHER_NODE);
2191
2192
2193
2194
2195
2196 up_read(&mm->mmap_sem);
2197 if (unlikely(!*hpage)) {
2198 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2199 *hpage = ERR_PTR(-ENOMEM);
2200 return NULL;
2201 }
2202
2203 count_vm_event(THP_COLLAPSE_ALLOC);
2204 return *hpage;
2205}
2206#else
2207static struct page *khugepaged_alloc_hugepage(bool *wait)
2208{
2209 struct page *hpage;
2210
2211 do {
2212 hpage = alloc_hugepage(khugepaged_defrag());
2213 if (!hpage) {
2214 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2215 if (!*wait)
2216 return NULL;
2217
2218 *wait = false;
2219 khugepaged_alloc_sleep();
2220 } else
2221 count_vm_event(THP_COLLAPSE_ALLOC);
2222 } while (unlikely(!hpage) && likely(khugepaged_enabled()));
2223
2224 return hpage;
2225}
2226
2227static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2228{
2229 if (!*hpage)
2230 *hpage = khugepaged_alloc_hugepage(wait);
2231
2232 if (unlikely(!*hpage))
2233 return false;
2234
2235 return true;
2236}
2237
2238static struct page
2239*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2240 struct vm_area_struct *vma, unsigned long address,
2241 int node)
2242{
2243 up_read(&mm->mmap_sem);
2244 VM_BUG_ON(!*hpage);
2245 return *hpage;
2246}
2247#endif
2248
2249static bool hugepage_vma_check(struct vm_area_struct *vma)
2250{
2251 if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
2252 (vma->vm_flags & VM_NOHUGEPAGE))
2253 return false;
2254
2255 if (!vma->anon_vma || vma->vm_ops)
2256 return false;
2257 if (is_vma_temporary_stack(vma))
2258 return false;
2259 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
2260 return true;
2261}
2262
2263static void collapse_huge_page(struct mm_struct *mm,
2264 unsigned long address,
2265 struct page **hpage,
2266 struct vm_area_struct *vma,
2267 int node)
2268{
2269 pmd_t *pmd, _pmd;
2270 pte_t *pte;
2271 pgtable_t pgtable;
2272 struct page *new_page;
2273 spinlock_t *ptl;
2274 int isolated;
2275 unsigned long hstart, hend;
2276 unsigned long mmun_start;
2277 unsigned long mmun_end;
2278
2279 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
2280
2281
2282 new_page = khugepaged_alloc_page(hpage, mm, vma, address, node);
2283 if (!new_page)
2284 return;
2285
2286 if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)))
2287 return;
2288
2289
2290
2291
2292
2293
2294 down_write(&mm->mmap_sem);
2295 if (unlikely(khugepaged_test_exit(mm)))
2296 goto out;
2297
2298 vma = find_vma(mm, address);
2299 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2300 hend = vma->vm_end & HPAGE_PMD_MASK;
2301 if (address < hstart || address + HPAGE_PMD_SIZE > hend)
2302 goto out;
2303 if (!hugepage_vma_check(vma))
2304 goto out;
2305 pmd = mm_find_pmd(mm, address);
2306 if (!pmd)
2307 goto out;
2308 if (pmd_trans_huge(*pmd))
2309 goto out;
2310
2311 anon_vma_lock_write(vma->anon_vma);
2312
2313 pte = pte_offset_map(pmd, address);
2314 ptl = pte_lockptr(mm, pmd);
2315
2316 mmun_start = address;
2317 mmun_end = address + HPAGE_PMD_SIZE;
2318 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2319 spin_lock(&mm->page_table_lock);
2320
2321
2322
2323
2324
2325
2326 _pmd = pmdp_clear_flush(vma, address, pmd);
2327 spin_unlock(&mm->page_table_lock);
2328 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2329
2330 spin_lock(ptl);
2331 isolated = __collapse_huge_page_isolate(vma, address, pte);
2332 spin_unlock(ptl);
2333
2334 if (unlikely(!isolated)) {
2335 pte_unmap(pte);
2336 spin_lock(&mm->page_table_lock);
2337 BUG_ON(!pmd_none(*pmd));
2338
2339
2340
2341
2342
2343 pmd_populate(mm, pmd, pmd_pgtable(_pmd));
2344 spin_unlock(&mm->page_table_lock);
2345 anon_vma_unlock_write(vma->anon_vma);
2346 goto out;
2347 }
2348
2349
2350
2351
2352
2353 anon_vma_unlock_write(vma->anon_vma);
2354
2355 __collapse_huge_page_copy(pte, new_page, vma, address, ptl);
2356 pte_unmap(pte);
2357 __SetPageUptodate(new_page);
2358 pgtable = pmd_pgtable(_pmd);
2359
2360 _pmd = mk_huge_pmd(new_page, vma);
2361
2362
2363
2364
2365
2366
2367 smp_wmb();
2368
2369 spin_lock(&mm->page_table_lock);
2370 BUG_ON(!pmd_none(*pmd));
2371 page_add_new_anon_rmap(new_page, vma, address);
2372 pgtable_trans_huge_deposit(mm, pmd, pgtable);
2373 set_pmd_at(mm, address, pmd, _pmd);
2374 update_mmu_cache_pmd(vma, address, pmd);
2375 spin_unlock(&mm->page_table_lock);
2376
2377 *hpage = NULL;
2378
2379 khugepaged_pages_collapsed++;
2380out_up_write:
2381 up_write(&mm->mmap_sem);
2382 return;
2383
2384out:
2385 mem_cgroup_uncharge_page(new_page);
2386 goto out_up_write;
2387}
2388
2389static int khugepaged_scan_pmd(struct mm_struct *mm,
2390 struct vm_area_struct *vma,
2391 unsigned long address,
2392 struct page **hpage)
2393{
2394 pmd_t *pmd;
2395 pte_t *pte, *_pte;
2396 int ret = 0, referenced = 0, none = 0;
2397 struct page *page;
2398 unsigned long _address;
2399 spinlock_t *ptl;
2400 int node = NUMA_NO_NODE;
2401
2402 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
2403
2404 pmd = mm_find_pmd(mm, address);
2405 if (!pmd)
2406 goto out;
2407 if (pmd_trans_huge(*pmd))
2408 goto out;
2409
2410 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2411 for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
2412 _pte++, _address += PAGE_SIZE) {
2413 pte_t pteval = *_pte;
2414 if (pte_none(pteval)) {
2415 if (++none <= khugepaged_max_ptes_none)
2416 continue;
2417 else
2418 goto out_unmap;
2419 }
2420 if (!pte_present(pteval) || !pte_write(pteval))
2421 goto out_unmap;
2422 page = vm_normal_page(vma, _address, pteval);
2423 if (unlikely(!page))
2424 goto out_unmap;
2425
2426
2427
2428
2429
2430 if (node == NUMA_NO_NODE)
2431 node = page_to_nid(page);
2432 VM_BUG_ON(PageCompound(page));
2433 if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
2434 goto out_unmap;
2435
2436 if (page_count(page) != 1)
2437 goto out_unmap;
2438 if (pte_young(pteval) || PageReferenced(page) ||
2439 mmu_notifier_test_young(vma->vm_mm, address))
2440 referenced = 1;
2441 }
2442 if (referenced)
2443 ret = 1;
2444out_unmap:
2445 pte_unmap_unlock(pte, ptl);
2446 if (ret)
2447
2448 collapse_huge_page(mm, address, hpage, vma, node);
2449out:
2450 return ret;
2451}
2452
2453static void collect_mm_slot(struct mm_slot *mm_slot)
2454{
2455 struct mm_struct *mm = mm_slot->mm;
2456
2457 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
2458
2459 if (khugepaged_test_exit(mm)) {
2460
2461 hash_del(&mm_slot->hash);
2462 list_del(&mm_slot->mm_node);
2463
2464
2465
2466
2467
2468
2469
2470
2471 free_mm_slot(mm_slot);
2472 mmdrop(mm);
2473 }
2474}
2475
2476static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
2477 struct page **hpage)
2478 __releases(&khugepaged_mm_lock)
2479 __acquires(&khugepaged_mm_lock)
2480{
2481 struct mm_slot *mm_slot;
2482 struct mm_struct *mm;
2483 struct vm_area_struct *vma;
2484 int progress = 0;
2485
2486 VM_BUG_ON(!pages);
2487 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
2488
2489 if (khugepaged_scan.mm_slot)
2490 mm_slot = khugepaged_scan.mm_slot;
2491 else {
2492 mm_slot = list_entry(khugepaged_scan.mm_head.next,
2493 struct mm_slot, mm_node);
2494 khugepaged_scan.address = 0;
2495 khugepaged_scan.mm_slot = mm_slot;
2496 }
2497 spin_unlock(&khugepaged_mm_lock);
2498
2499 mm = mm_slot->mm;
2500 down_read(&mm->mmap_sem);
2501 if (unlikely(khugepaged_test_exit(mm)))
2502 vma = NULL;
2503 else
2504 vma = find_vma(mm, khugepaged_scan.address);
2505
2506 progress++;
2507 for (; vma; vma = vma->vm_next) {
2508 unsigned long hstart, hend;
2509
2510 cond_resched();
2511 if (unlikely(khugepaged_test_exit(mm))) {
2512 progress++;
2513 break;
2514 }
2515 if (!hugepage_vma_check(vma)) {
2516skip:
2517 progress++;
2518 continue;
2519 }
2520 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2521 hend = vma->vm_end & HPAGE_PMD_MASK;
2522 if (hstart >= hend)
2523 goto skip;
2524 if (khugepaged_scan.address > hend)
2525 goto skip;
2526 if (khugepaged_scan.address < hstart)
2527 khugepaged_scan.address = hstart;
2528 VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK);
2529
2530 while (khugepaged_scan.address < hend) {
2531 int ret;
2532 cond_resched();
2533 if (unlikely(khugepaged_test_exit(mm)))
2534 goto breakouterloop;
2535
2536 VM_BUG_ON(khugepaged_scan.address < hstart ||
2537 khugepaged_scan.address + HPAGE_PMD_SIZE >
2538 hend);
2539 ret = khugepaged_scan_pmd(mm, vma,
2540 khugepaged_scan.address,
2541 hpage);
2542
2543 khugepaged_scan.address += HPAGE_PMD_SIZE;
2544 progress += HPAGE_PMD_NR;
2545 if (ret)
2546
2547 goto breakouterloop_mmap_sem;
2548 if (progress >= pages)
2549 goto breakouterloop;
2550 }
2551 }
2552breakouterloop:
2553 up_read(&mm->mmap_sem);
2554breakouterloop_mmap_sem:
2555
2556 spin_lock(&khugepaged_mm_lock);
2557 VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot);
2558
2559
2560
2561
2562 if (khugepaged_test_exit(mm) || !vma) {
2563
2564
2565
2566
2567
2568 if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
2569 khugepaged_scan.mm_slot = list_entry(
2570 mm_slot->mm_node.next,
2571 struct mm_slot, mm_node);
2572 khugepaged_scan.address = 0;
2573 } else {
2574 khugepaged_scan.mm_slot = NULL;
2575 khugepaged_full_scans++;
2576 }
2577
2578 collect_mm_slot(mm_slot);
2579 }
2580
2581 return progress;
2582}
2583
2584static int khugepaged_has_work(void)
2585{
2586 return !list_empty(&khugepaged_scan.mm_head) &&
2587 khugepaged_enabled();
2588}
2589
2590static int khugepaged_wait_event(void)
2591{
2592 return !list_empty(&khugepaged_scan.mm_head) ||
2593 kthread_should_stop();
2594}
2595
2596static void khugepaged_do_scan(void)
2597{
2598 struct page *hpage = NULL;
2599 unsigned int progress = 0, pass_through_head = 0;
2600 unsigned int pages = khugepaged_pages_to_scan;
2601 bool wait = true;
2602
2603 barrier();
2604
2605 while (progress < pages) {
2606 if (!khugepaged_prealloc_page(&hpage, &wait))
2607 break;
2608
2609 cond_resched();
2610
2611 if (unlikely(kthread_should_stop() || freezing(current)))
2612 break;
2613
2614 spin_lock(&khugepaged_mm_lock);
2615 if (!khugepaged_scan.mm_slot)
2616 pass_through_head++;
2617 if (khugepaged_has_work() &&
2618 pass_through_head < 2)
2619 progress += khugepaged_scan_mm_slot(pages - progress,
2620 &hpage);
2621 else
2622 progress = pages;
2623 spin_unlock(&khugepaged_mm_lock);
2624 }
2625
2626 if (!IS_ERR_OR_NULL(hpage))
2627 put_page(hpage);
2628}
2629
2630static void khugepaged_wait_work(void)
2631{
2632 try_to_freeze();
2633
2634 if (khugepaged_has_work()) {
2635 if (!khugepaged_scan_sleep_millisecs)
2636 return;
2637
2638 wait_event_freezable_timeout(khugepaged_wait,
2639 kthread_should_stop(),
2640 msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
2641 return;
2642 }
2643
2644 if (khugepaged_enabled())
2645 wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
2646}
2647
2648static int khugepaged(void *none)
2649{
2650 struct mm_slot *mm_slot;
2651
2652 set_freezable();
2653 set_user_nice(current, 19);
2654
2655 while (!kthread_should_stop()) {
2656 khugepaged_do_scan();
2657 khugepaged_wait_work();
2658 }
2659
2660 spin_lock(&khugepaged_mm_lock);
2661 mm_slot = khugepaged_scan.mm_slot;
2662 khugepaged_scan.mm_slot = NULL;
2663 if (mm_slot)
2664 collect_mm_slot(mm_slot);
2665 spin_unlock(&khugepaged_mm_lock);
2666 return 0;
2667}
2668
2669static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
2670 unsigned long haddr, pmd_t *pmd)
2671{
2672 struct mm_struct *mm = vma->vm_mm;
2673 pgtable_t pgtable;
2674 pmd_t _pmd;
2675 int i;
2676
2677 pmdp_clear_flush(vma, haddr, pmd);
2678
2679
2680 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
2681 pmd_populate(mm, &_pmd, pgtable);
2682
2683 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
2684 pte_t *pte, entry;
2685 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
2686 entry = pte_mkspecial(entry);
2687 pte = pte_offset_map(&_pmd, haddr);
2688 VM_BUG_ON(!pte_none(*pte));
2689 set_pte_at(mm, haddr, pte, entry);
2690 pte_unmap(pte);
2691 }
2692 smp_wmb();
2693 pmd_populate(mm, pmd, pgtable);
2694 put_huge_zero_page();
2695}
2696
2697void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
2698 pmd_t *pmd)
2699{
2700 struct page *page;
2701 struct mm_struct *mm = vma->vm_mm;
2702 unsigned long haddr = address & HPAGE_PMD_MASK;
2703 unsigned long mmun_start;
2704 unsigned long mmun_end;
2705
2706 BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE);
2707
2708 mmun_start = haddr;
2709 mmun_end = haddr + HPAGE_PMD_SIZE;
2710 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2711 spin_lock(&mm->page_table_lock);
2712 if (unlikely(!pmd_trans_huge(*pmd))) {
2713 spin_unlock(&mm->page_table_lock);
2714 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2715 return;
2716 }
2717 if (is_huge_zero_pmd(*pmd)) {
2718 __split_huge_zero_page_pmd(vma, haddr, pmd);
2719 spin_unlock(&mm->page_table_lock);
2720 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2721 return;
2722 }
2723 page = pmd_page(*pmd);
2724 VM_BUG_ON(!page_count(page));
2725 get_page(page);
2726 spin_unlock(&mm->page_table_lock);
2727 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2728
2729 split_huge_page(page);
2730
2731 put_page(page);
2732 BUG_ON(pmd_trans_huge(*pmd));
2733}
2734
2735void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
2736 pmd_t *pmd)
2737{
2738 struct vm_area_struct *vma;
2739
2740 vma = find_vma(mm, address);
2741 BUG_ON(vma == NULL);
2742 split_huge_page_pmd(vma, address, pmd);
2743}
2744
2745static void split_huge_page_address(struct mm_struct *mm,
2746 unsigned long address)
2747{
2748 pmd_t *pmd;
2749
2750 VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
2751
2752 pmd = mm_find_pmd(mm, address);
2753 if (!pmd)
2754 return;
2755
2756
2757
2758
2759 split_huge_page_pmd_mm(mm, address, pmd);
2760}
2761
2762void __vma_adjust_trans_huge(struct vm_area_struct *vma,
2763 unsigned long start,
2764 unsigned long end,
2765 long adjust_next)
2766{
2767
2768
2769
2770
2771
2772 if (start & ~HPAGE_PMD_MASK &&
2773 (start & HPAGE_PMD_MASK) >= vma->vm_start &&
2774 (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2775 split_huge_page_address(vma->vm_mm, start);
2776
2777
2778
2779
2780
2781
2782 if (end & ~HPAGE_PMD_MASK &&
2783 (end & HPAGE_PMD_MASK) >= vma->vm_start &&
2784 (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2785 split_huge_page_address(vma->vm_mm, end);
2786
2787
2788
2789
2790
2791
2792 if (adjust_next > 0) {
2793 struct vm_area_struct *next = vma->vm_next;
2794 unsigned long nstart = next->vm_start;
2795 nstart += adjust_next << PAGE_SHIFT;
2796 if (nstart & ~HPAGE_PMD_MASK &&
2797 (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
2798 (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
2799 split_huge_page_address(next->vm_mm, nstart);
2800 }
2801}
2802