1
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5
6
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/mm.h>
11#include <linux/sched.h>
12#include <linux/highmem.h>
13#include <linux/hugetlb.h>
14#include <linux/mmu_notifier.h>
15#include <linux/rmap.h>
16#include <linux/swap.h>
17#include <linux/shrinker.h>
18#include <linux/mm_inline.h>
19#include <linux/kthread.h>
20#include <linux/khugepaged.h>
21#include <linux/freezer.h>
22#include <linux/mman.h>
23#include <linux/pagemap.h>
24#include <linux/migrate.h>
25#include <linux/hashtable.h>
26
27#include <asm/tlb.h>
28#include <asm/pgalloc.h>
29#include "internal.h"
30
31
32
33
34
35
36
37
38
39unsigned long transparent_hugepage_flags __read_mostly =
40#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
41 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
42#endif
43#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
44 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
45#endif
46 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
47 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
48 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
49
50
51static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8;
52static unsigned int khugepaged_pages_collapsed;
53static unsigned int khugepaged_full_scans;
54static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000;
55
56static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000;
57static struct task_struct *khugepaged_thread __read_mostly;
58static DEFINE_MUTEX(khugepaged_mutex);
59static DEFINE_SPINLOCK(khugepaged_mm_lock);
60static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
61
62
63
64
65
66static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1;
67
68static int khugepaged(void *none);
69static int khugepaged_slab_init(void);
70
71#define MM_SLOTS_HASH_BITS 10
72static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
73
74static struct kmem_cache *mm_slot_cache __read_mostly;
75
76
77
78
79
80
81
82struct mm_slot {
83 struct hlist_node hash;
84 struct list_head mm_node;
85 struct mm_struct *mm;
86};
87
88
89
90
91
92
93
94
95
96struct khugepaged_scan {
97 struct list_head mm_head;
98 struct mm_slot *mm_slot;
99 unsigned long address;
100};
101static struct khugepaged_scan khugepaged_scan = {
102 .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
103};
104
105
106static int set_recommended_min_free_kbytes(void)
107{
108 struct zone *zone;
109 int nr_zones = 0;
110 unsigned long recommended_min;
111
112 if (!khugepaged_enabled())
113 return 0;
114
115 for_each_populated_zone(zone)
116 nr_zones++;
117
118
119 recommended_min = pageblock_nr_pages * nr_zones * 2;
120
121
122
123
124
125
126
127 recommended_min += pageblock_nr_pages * nr_zones *
128 MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
129
130
131 recommended_min = min(recommended_min,
132 (unsigned long) nr_free_buffer_pages() / 20);
133 recommended_min <<= (PAGE_SHIFT-10);
134
135 if (recommended_min > min_free_kbytes) {
136 if (user_min_free_kbytes >= 0)
137 pr_info("raising min_free_kbytes from %d to %lu "
138 "to help transparent hugepage allocations\n",
139 min_free_kbytes, recommended_min);
140
141 min_free_kbytes = recommended_min;
142 }
143 setup_per_zone_wmarks();
144 return 0;
145}
146late_initcall(set_recommended_min_free_kbytes);
147
148static int start_khugepaged(void)
149{
150 int err = 0;
151 if (khugepaged_enabled()) {
152 if (!khugepaged_thread)
153 khugepaged_thread = kthread_run(khugepaged, NULL,
154 "khugepaged");
155 if (unlikely(IS_ERR(khugepaged_thread))) {
156 pr_err("khugepaged: kthread_run(khugepaged) failed\n");
157 err = PTR_ERR(khugepaged_thread);
158 khugepaged_thread = NULL;
159 }
160
161 if (!list_empty(&khugepaged_scan.mm_head))
162 wake_up_interruptible(&khugepaged_wait);
163
164 set_recommended_min_free_kbytes();
165 } else if (khugepaged_thread) {
166 kthread_stop(khugepaged_thread);
167 khugepaged_thread = NULL;
168 }
169
170 return err;
171}
172
173static atomic_t huge_zero_refcount;
174static struct page *huge_zero_page __read_mostly;
175
176static inline bool is_huge_zero_page(struct page *page)
177{
178 return ACCESS_ONCE(huge_zero_page) == page;
179}
180
181static inline bool is_huge_zero_pmd(pmd_t pmd)
182{
183 return is_huge_zero_page(pmd_page(pmd));
184}
185
186static struct page *get_huge_zero_page(void)
187{
188 struct page *zero_page;
189retry:
190 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
191 return ACCESS_ONCE(huge_zero_page);
192
193 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
194 HPAGE_PMD_ORDER);
195 if (!zero_page) {
196 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
197 return NULL;
198 }
199 count_vm_event(THP_ZERO_PAGE_ALLOC);
200 preempt_disable();
201 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
202 preempt_enable();
203 __free_page(zero_page);
204 goto retry;
205 }
206
207
208 atomic_set(&huge_zero_refcount, 2);
209 preempt_enable();
210 return ACCESS_ONCE(huge_zero_page);
211}
212
213static void put_huge_zero_page(void)
214{
215
216
217
218
219 BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
220}
221
222static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink,
223 struct shrink_control *sc)
224{
225
226 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
227}
228
229static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
230 struct shrink_control *sc)
231{
232 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
233 struct page *zero_page = xchg(&huge_zero_page, NULL);
234 BUG_ON(zero_page == NULL);
235 __free_page(zero_page);
236 return HPAGE_PMD_NR;
237 }
238
239 return 0;
240}
241
242static struct shrinker huge_zero_page_shrinker = {
243 .count_objects = shrink_huge_zero_page_count,
244 .scan_objects = shrink_huge_zero_page_scan,
245 .seeks = DEFAULT_SEEKS,
246};
247
248#ifdef CONFIG_SYSFS
249
250static ssize_t double_flag_show(struct kobject *kobj,
251 struct kobj_attribute *attr, char *buf,
252 enum transparent_hugepage_flag enabled,
253 enum transparent_hugepage_flag req_madv)
254{
255 if (test_bit(enabled, &transparent_hugepage_flags)) {
256 VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags));
257 return sprintf(buf, "[always] madvise never\n");
258 } else if (test_bit(req_madv, &transparent_hugepage_flags))
259 return sprintf(buf, "always [madvise] never\n");
260 else
261 return sprintf(buf, "always madvise [never]\n");
262}
263static ssize_t double_flag_store(struct kobject *kobj,
264 struct kobj_attribute *attr,
265 const char *buf, size_t count,
266 enum transparent_hugepage_flag enabled,
267 enum transparent_hugepage_flag req_madv)
268{
269 if (!memcmp("always", buf,
270 min(sizeof("always")-1, count))) {
271 set_bit(enabled, &transparent_hugepage_flags);
272 clear_bit(req_madv, &transparent_hugepage_flags);
273 } else if (!memcmp("madvise", buf,
274 min(sizeof("madvise")-1, count))) {
275 clear_bit(enabled, &transparent_hugepage_flags);
276 set_bit(req_madv, &transparent_hugepage_flags);
277 } else if (!memcmp("never", buf,
278 min(sizeof("never")-1, count))) {
279 clear_bit(enabled, &transparent_hugepage_flags);
280 clear_bit(req_madv, &transparent_hugepage_flags);
281 } else
282 return -EINVAL;
283
284 return count;
285}
286
287static ssize_t enabled_show(struct kobject *kobj,
288 struct kobj_attribute *attr, char *buf)
289{
290 return double_flag_show(kobj, attr, buf,
291 TRANSPARENT_HUGEPAGE_FLAG,
292 TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
293}
294static ssize_t enabled_store(struct kobject *kobj,
295 struct kobj_attribute *attr,
296 const char *buf, size_t count)
297{
298 ssize_t ret;
299
300 ret = double_flag_store(kobj, attr, buf, count,
301 TRANSPARENT_HUGEPAGE_FLAG,
302 TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
303
304 if (ret > 0) {
305 int err;
306
307 mutex_lock(&khugepaged_mutex);
308 err = start_khugepaged();
309 mutex_unlock(&khugepaged_mutex);
310
311 if (err)
312 ret = err;
313 }
314
315 return ret;
316}
317static struct kobj_attribute enabled_attr =
318 __ATTR(enabled, 0644, enabled_show, enabled_store);
319
320static ssize_t single_flag_show(struct kobject *kobj,
321 struct kobj_attribute *attr, char *buf,
322 enum transparent_hugepage_flag flag)
323{
324 return sprintf(buf, "%d\n",
325 !!test_bit(flag, &transparent_hugepage_flags));
326}
327
328static ssize_t single_flag_store(struct kobject *kobj,
329 struct kobj_attribute *attr,
330 const char *buf, size_t count,
331 enum transparent_hugepage_flag flag)
332{
333 unsigned long value;
334 int ret;
335
336 ret = kstrtoul(buf, 10, &value);
337 if (ret < 0)
338 return ret;
339 if (value > 1)
340 return -EINVAL;
341
342 if (value)
343 set_bit(flag, &transparent_hugepage_flags);
344 else
345 clear_bit(flag, &transparent_hugepage_flags);
346
347 return count;
348}
349
350
351
352
353
354
355static ssize_t defrag_show(struct kobject *kobj,
356 struct kobj_attribute *attr, char *buf)
357{
358 return double_flag_show(kobj, attr, buf,
359 TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
360 TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG);
361}
362static ssize_t defrag_store(struct kobject *kobj,
363 struct kobj_attribute *attr,
364 const char *buf, size_t count)
365{
366 return double_flag_store(kobj, attr, buf, count,
367 TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
368 TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG);
369}
370static struct kobj_attribute defrag_attr =
371 __ATTR(defrag, 0644, defrag_show, defrag_store);
372
373static ssize_t use_zero_page_show(struct kobject *kobj,
374 struct kobj_attribute *attr, char *buf)
375{
376 return single_flag_show(kobj, attr, buf,
377 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
378}
379static ssize_t use_zero_page_store(struct kobject *kobj,
380 struct kobj_attribute *attr, const char *buf, size_t count)
381{
382 return single_flag_store(kobj, attr, buf, count,
383 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
384}
385static struct kobj_attribute use_zero_page_attr =
386 __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
387#ifdef CONFIG_DEBUG_VM
388static ssize_t debug_cow_show(struct kobject *kobj,
389 struct kobj_attribute *attr, char *buf)
390{
391 return single_flag_show(kobj, attr, buf,
392 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
393}
394static ssize_t debug_cow_store(struct kobject *kobj,
395 struct kobj_attribute *attr,
396 const char *buf, size_t count)
397{
398 return single_flag_store(kobj, attr, buf, count,
399 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
400}
401static struct kobj_attribute debug_cow_attr =
402 __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store);
403#endif
404
405static struct attribute *hugepage_attr[] = {
406 &enabled_attr.attr,
407 &defrag_attr.attr,
408 &use_zero_page_attr.attr,
409#ifdef CONFIG_DEBUG_VM
410 &debug_cow_attr.attr,
411#endif
412 NULL,
413};
414
415static struct attribute_group hugepage_attr_group = {
416 .attrs = hugepage_attr,
417};
418
419static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
420 struct kobj_attribute *attr,
421 char *buf)
422{
423 return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs);
424}
425
426static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
427 struct kobj_attribute *attr,
428 const char *buf, size_t count)
429{
430 unsigned long msecs;
431 int err;
432
433 err = kstrtoul(buf, 10, &msecs);
434 if (err || msecs > UINT_MAX)
435 return -EINVAL;
436
437 khugepaged_scan_sleep_millisecs = msecs;
438 wake_up_interruptible(&khugepaged_wait);
439
440 return count;
441}
442static struct kobj_attribute scan_sleep_millisecs_attr =
443 __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show,
444 scan_sleep_millisecs_store);
445
446static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj,
447 struct kobj_attribute *attr,
448 char *buf)
449{
450 return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs);
451}
452
453static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj,
454 struct kobj_attribute *attr,
455 const char *buf, size_t count)
456{
457 unsigned long msecs;
458 int err;
459
460 err = kstrtoul(buf, 10, &msecs);
461 if (err || msecs > UINT_MAX)
462 return -EINVAL;
463
464 khugepaged_alloc_sleep_millisecs = msecs;
465 wake_up_interruptible(&khugepaged_wait);
466
467 return count;
468}
469static struct kobj_attribute alloc_sleep_millisecs_attr =
470 __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show,
471 alloc_sleep_millisecs_store);
472
473static ssize_t pages_to_scan_show(struct kobject *kobj,
474 struct kobj_attribute *attr,
475 char *buf)
476{
477 return sprintf(buf, "%u\n", khugepaged_pages_to_scan);
478}
479static ssize_t pages_to_scan_store(struct kobject *kobj,
480 struct kobj_attribute *attr,
481 const char *buf, size_t count)
482{
483 int err;
484 unsigned long pages;
485
486 err = kstrtoul(buf, 10, &pages);
487 if (err || !pages || pages > UINT_MAX)
488 return -EINVAL;
489
490 khugepaged_pages_to_scan = pages;
491
492 return count;
493}
494static struct kobj_attribute pages_to_scan_attr =
495 __ATTR(pages_to_scan, 0644, pages_to_scan_show,
496 pages_to_scan_store);
497
498static ssize_t pages_collapsed_show(struct kobject *kobj,
499 struct kobj_attribute *attr,
500 char *buf)
501{
502 return sprintf(buf, "%u\n", khugepaged_pages_collapsed);
503}
504static struct kobj_attribute pages_collapsed_attr =
505 __ATTR_RO(pages_collapsed);
506
507static ssize_t full_scans_show(struct kobject *kobj,
508 struct kobj_attribute *attr,
509 char *buf)
510{
511 return sprintf(buf, "%u\n", khugepaged_full_scans);
512}
513static struct kobj_attribute full_scans_attr =
514 __ATTR_RO(full_scans);
515
516static ssize_t khugepaged_defrag_show(struct kobject *kobj,
517 struct kobj_attribute *attr, char *buf)
518{
519 return single_flag_show(kobj, attr, buf,
520 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
521}
522static ssize_t khugepaged_defrag_store(struct kobject *kobj,
523 struct kobj_attribute *attr,
524 const char *buf, size_t count)
525{
526 return single_flag_store(kobj, attr, buf, count,
527 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
528}
529static struct kobj_attribute khugepaged_defrag_attr =
530 __ATTR(defrag, 0644, khugepaged_defrag_show,
531 khugepaged_defrag_store);
532
533
534
535
536
537
538
539
540
541static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj,
542 struct kobj_attribute *attr,
543 char *buf)
544{
545 return sprintf(buf, "%u\n", khugepaged_max_ptes_none);
546}
547static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj,
548 struct kobj_attribute *attr,
549 const char *buf, size_t count)
550{
551 int err;
552 unsigned long max_ptes_none;
553
554 err = kstrtoul(buf, 10, &max_ptes_none);
555 if (err || max_ptes_none > HPAGE_PMD_NR-1)
556 return -EINVAL;
557
558 khugepaged_max_ptes_none = max_ptes_none;
559
560 return count;
561}
562static struct kobj_attribute khugepaged_max_ptes_none_attr =
563 __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show,
564 khugepaged_max_ptes_none_store);
565
566static struct attribute *khugepaged_attr[] = {
567 &khugepaged_defrag_attr.attr,
568 &khugepaged_max_ptes_none_attr.attr,
569 &pages_to_scan_attr.attr,
570 &pages_collapsed_attr.attr,
571 &full_scans_attr.attr,
572 &scan_sleep_millisecs_attr.attr,
573 &alloc_sleep_millisecs_attr.attr,
574 NULL,
575};
576
577static struct attribute_group khugepaged_attr_group = {
578 .attrs = khugepaged_attr,
579 .name = "khugepaged",
580};
581
582static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
583{
584 int err;
585
586 *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
587 if (unlikely(!*hugepage_kobj)) {
588 pr_err("failed to create transparent hugepage kobject\n");
589 return -ENOMEM;
590 }
591
592 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
593 if (err) {
594 pr_err("failed to register transparent hugepage group\n");
595 goto delete_obj;
596 }
597
598 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
599 if (err) {
600 pr_err("failed to register transparent hugepage group\n");
601 goto remove_hp_group;
602 }
603
604 return 0;
605
606remove_hp_group:
607 sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group);
608delete_obj:
609 kobject_put(*hugepage_kobj);
610 return err;
611}
612
613static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj)
614{
615 sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
616 sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
617 kobject_put(hugepage_kobj);
618}
619#else
620static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj)
621{
622 return 0;
623}
624
625static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj)
626{
627}
628#endif
629
630static int __init hugepage_init(void)
631{
632 int err;
633 struct kobject *hugepage_kobj;
634
635 if (!has_transparent_hugepage()) {
636 transparent_hugepage_flags = 0;
637 return -EINVAL;
638 }
639
640 err = hugepage_init_sysfs(&hugepage_kobj);
641 if (err)
642 return err;
643
644 err = khugepaged_slab_init();
645 if (err)
646 goto out;
647
648 register_shrinker(&huge_zero_page_shrinker);
649
650
651
652
653
654
655 if (totalram_pages < (512 << (20 - PAGE_SHIFT)))
656 transparent_hugepage_flags = 0;
657
658 start_khugepaged();
659
660 return 0;
661out:
662 hugepage_exit_sysfs(hugepage_kobj);
663 return err;
664}
665subsys_initcall(hugepage_init);
666
667static int __init setup_transparent_hugepage(char *str)
668{
669 int ret = 0;
670 if (!str)
671 goto out;
672 if (!strcmp(str, "always")) {
673 set_bit(TRANSPARENT_HUGEPAGE_FLAG,
674 &transparent_hugepage_flags);
675 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
676 &transparent_hugepage_flags);
677 ret = 1;
678 } else if (!strcmp(str, "madvise")) {
679 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
680 &transparent_hugepage_flags);
681 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
682 &transparent_hugepage_flags);
683 ret = 1;
684 } else if (!strcmp(str, "never")) {
685 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
686 &transparent_hugepage_flags);
687 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
688 &transparent_hugepage_flags);
689 ret = 1;
690 }
691out:
692 if (!ret)
693 pr_warn("transparent_hugepage= cannot parse, ignored\n");
694 return ret;
695}
696__setup("transparent_hugepage=", setup_transparent_hugepage);
697
698pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
699{
700 if (likely(vma->vm_flags & VM_WRITE))
701 pmd = pmd_mkwrite(pmd);
702 return pmd;
703}
704
705static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot)
706{
707 pmd_t entry;
708 entry = mk_pmd(page, prot);
709 entry = pmd_mkhuge(entry);
710 return entry;
711}
712
713static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
714 struct vm_area_struct *vma,
715 unsigned long haddr, pmd_t *pmd,
716 struct page *page)
717{
718 pgtable_t pgtable;
719 spinlock_t *ptl;
720
721 VM_BUG_ON_PAGE(!PageCompound(page), page);
722 pgtable = pte_alloc_one(mm, haddr);
723 if (unlikely(!pgtable))
724 return VM_FAULT_OOM;
725
726 clear_huge_page(page, haddr, HPAGE_PMD_NR);
727
728
729
730
731
732 __SetPageUptodate(page);
733
734 ptl = pmd_lock(mm, pmd);
735 if (unlikely(!pmd_none(*pmd))) {
736 spin_unlock(ptl);
737 mem_cgroup_uncharge_page(page);
738 put_page(page);
739 pte_free(mm, pgtable);
740 } else {
741 pmd_t entry;
742 entry = mk_huge_pmd(page, vma->vm_page_prot);
743 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
744 page_add_new_anon_rmap(page, vma, haddr);
745 pgtable_trans_huge_deposit(mm, pmd, pgtable);
746 set_pmd_at(mm, haddr, pmd, entry);
747 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
748 atomic_long_inc(&mm->nr_ptes);
749 spin_unlock(ptl);
750 }
751
752 return 0;
753}
754
755static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp)
756{
757 return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp;
758}
759
760static inline struct page *alloc_hugepage_vma(int defrag,
761 struct vm_area_struct *vma,
762 unsigned long haddr, int nd,
763 gfp_t extra_gfp)
764{
765 return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp),
766 HPAGE_PMD_ORDER, vma, haddr, nd);
767}
768
769
770static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
771 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
772 struct page *zero_page)
773{
774 pmd_t entry;
775 if (!pmd_none(*pmd))
776 return false;
777 entry = mk_pmd(zero_page, vma->vm_page_prot);
778 entry = pmd_wrprotect(entry);
779 entry = pmd_mkhuge(entry);
780 pgtable_trans_huge_deposit(mm, pmd, pgtable);
781 set_pmd_at(mm, haddr, pmd, entry);
782 atomic_long_inc(&mm->nr_ptes);
783 return true;
784}
785
786int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
787 unsigned long address, pmd_t *pmd,
788 unsigned int flags)
789{
790 struct page *page;
791 unsigned long haddr = address & HPAGE_PMD_MASK;
792
793 if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
794 return VM_FAULT_FALLBACK;
795 if (unlikely(anon_vma_prepare(vma)))
796 return VM_FAULT_OOM;
797 if (unlikely(khugepaged_enter(vma)))
798 return VM_FAULT_OOM;
799 if (!(flags & FAULT_FLAG_WRITE) &&
800 transparent_hugepage_use_zero_page()) {
801 spinlock_t *ptl;
802 pgtable_t pgtable;
803 struct page *zero_page;
804 bool set;
805 pgtable = pte_alloc_one(mm, haddr);
806 if (unlikely(!pgtable))
807 return VM_FAULT_OOM;
808 zero_page = get_huge_zero_page();
809 if (unlikely(!zero_page)) {
810 pte_free(mm, pgtable);
811 count_vm_event(THP_FAULT_FALLBACK);
812 return VM_FAULT_FALLBACK;
813 }
814 ptl = pmd_lock(mm, pmd);
815 set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd,
816 zero_page);
817 spin_unlock(ptl);
818 if (!set) {
819 pte_free(mm, pgtable);
820 put_huge_zero_page();
821 }
822 return 0;
823 }
824 page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
825 vma, haddr, numa_node_id(), 0);
826 if (unlikely(!page)) {
827 count_vm_event(THP_FAULT_FALLBACK);
828 return VM_FAULT_FALLBACK;
829 }
830 if (unlikely(mem_cgroup_charge_anon(page, mm, GFP_KERNEL))) {
831 put_page(page);
832 count_vm_event(THP_FAULT_FALLBACK);
833 return VM_FAULT_FALLBACK;
834 }
835 if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) {
836 mem_cgroup_uncharge_page(page);
837 put_page(page);
838 count_vm_event(THP_FAULT_FALLBACK);
839 return VM_FAULT_FALLBACK;
840 }
841
842 count_vm_event(THP_FAULT_ALLOC);
843 return 0;
844}
845
846int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
847 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
848 struct vm_area_struct *vma)
849{
850 spinlock_t *dst_ptl, *src_ptl;
851 struct page *src_page;
852 pmd_t pmd;
853 pgtable_t pgtable;
854 int ret;
855
856 ret = -ENOMEM;
857 pgtable = pte_alloc_one(dst_mm, addr);
858 if (unlikely(!pgtable))
859 goto out;
860
861 dst_ptl = pmd_lock(dst_mm, dst_pmd);
862 src_ptl = pmd_lockptr(src_mm, src_pmd);
863 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
864
865 ret = -EAGAIN;
866 pmd = *src_pmd;
867 if (unlikely(!pmd_trans_huge(pmd))) {
868 pte_free(dst_mm, pgtable);
869 goto out_unlock;
870 }
871
872
873
874
875
876 if (is_huge_zero_pmd(pmd)) {
877 struct page *zero_page;
878 bool set;
879
880
881
882
883
884 zero_page = get_huge_zero_page();
885 set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd,
886 zero_page);
887 BUG_ON(!set);
888 ret = 0;
889 goto out_unlock;
890 }
891
892 if (unlikely(pmd_trans_splitting(pmd))) {
893
894 spin_unlock(src_ptl);
895 spin_unlock(dst_ptl);
896 pte_free(dst_mm, pgtable);
897
898 wait_split_huge_page(vma->anon_vma, src_pmd);
899 goto out;
900 }
901 src_page = pmd_page(pmd);
902 VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
903 get_page(src_page);
904 page_dup_rmap(src_page);
905 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
906
907 pmdp_set_wrprotect(src_mm, addr, src_pmd);
908 pmd = pmd_mkold(pmd_wrprotect(pmd));
909 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
910 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
911 atomic_long_inc(&dst_mm->nr_ptes);
912
913 ret = 0;
914out_unlock:
915 spin_unlock(src_ptl);
916 spin_unlock(dst_ptl);
917out:
918 return ret;
919}
920
921void huge_pmd_set_accessed(struct mm_struct *mm,
922 struct vm_area_struct *vma,
923 unsigned long address,
924 pmd_t *pmd, pmd_t orig_pmd,
925 int dirty)
926{
927 spinlock_t *ptl;
928 pmd_t entry;
929 unsigned long haddr;
930
931 ptl = pmd_lock(mm, pmd);
932 if (unlikely(!pmd_same(*pmd, orig_pmd)))
933 goto unlock;
934
935 entry = pmd_mkyoung(orig_pmd);
936 haddr = address & HPAGE_PMD_MASK;
937 if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty))
938 update_mmu_cache_pmd(vma, address, pmd);
939
940unlock:
941 spin_unlock(ptl);
942}
943
944
945
946
947
948
949
950static void get_user_huge_page(struct page *page)
951{
952 if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
953 struct page *endpage = page + HPAGE_PMD_NR;
954
955 atomic_add(HPAGE_PMD_NR, &page->_count);
956 while (++page < endpage)
957 get_huge_page_tail(page);
958 } else {
959 get_page(page);
960 }
961}
962
963static void put_user_huge_page(struct page *page)
964{
965 if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
966 struct page *endpage = page + HPAGE_PMD_NR;
967
968 while (page < endpage)
969 put_page(page++);
970 } else {
971 put_page(page);
972 }
973}
974
975static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
976 struct vm_area_struct *vma,
977 unsigned long address,
978 pmd_t *pmd, pmd_t orig_pmd,
979 struct page *page,
980 unsigned long haddr)
981{
982 spinlock_t *ptl;
983 pgtable_t pgtable;
984 pmd_t _pmd;
985 int ret = 0, i;
986 struct page **pages;
987 unsigned long mmun_start;
988 unsigned long mmun_end;
989
990 pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR,
991 GFP_KERNEL);
992 if (unlikely(!pages)) {
993 ret |= VM_FAULT_OOM;
994 goto out;
995 }
996
997 for (i = 0; i < HPAGE_PMD_NR; i++) {
998 pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE |
999 __GFP_OTHER_NODE,
1000 vma, address, page_to_nid(page));
1001 if (unlikely(!pages[i] ||
1002 mem_cgroup_charge_anon(pages[i], mm,
1003 GFP_KERNEL))) {
1004 if (pages[i])
1005 put_page(pages[i]);
1006 mem_cgroup_uncharge_start();
1007 while (--i >= 0) {
1008 mem_cgroup_uncharge_page(pages[i]);
1009 put_page(pages[i]);
1010 }
1011 mem_cgroup_uncharge_end();
1012 kfree(pages);
1013 ret |= VM_FAULT_OOM;
1014 goto out;
1015 }
1016 }
1017
1018 for (i = 0; i < HPAGE_PMD_NR; i++) {
1019 copy_user_highpage(pages[i], page + i,
1020 haddr + PAGE_SIZE * i, vma);
1021 __SetPageUptodate(pages[i]);
1022 cond_resched();
1023 }
1024
1025 mmun_start = haddr;
1026 mmun_end = haddr + HPAGE_PMD_SIZE;
1027 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1028
1029 ptl = pmd_lock(mm, pmd);
1030 if (unlikely(!pmd_same(*pmd, orig_pmd)))
1031 goto out_free_pages;
1032 VM_BUG_ON_PAGE(!PageHead(page), page);
1033
1034 pmdp_clear_flush(vma, haddr, pmd);
1035
1036
1037 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1038 pmd_populate(mm, &_pmd, pgtable);
1039
1040 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1041 pte_t *pte, entry;
1042 entry = mk_pte(pages[i], vma->vm_page_prot);
1043 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1044 page_add_new_anon_rmap(pages[i], vma, haddr);
1045 pte = pte_offset_map(&_pmd, haddr);
1046 VM_BUG_ON(!pte_none(*pte));
1047 set_pte_at(mm, haddr, pte, entry);
1048 pte_unmap(pte);
1049 }
1050 kfree(pages);
1051
1052 smp_wmb();
1053 pmd_populate(mm, pmd, pgtable);
1054 page_remove_rmap(page);
1055 spin_unlock(ptl);
1056
1057 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1058
1059 ret |= VM_FAULT_WRITE;
1060 put_page(page);
1061
1062out:
1063 return ret;
1064
1065out_free_pages:
1066 spin_unlock(ptl);
1067 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1068 mem_cgroup_uncharge_start();
1069 for (i = 0; i < HPAGE_PMD_NR; i++) {
1070 mem_cgroup_uncharge_page(pages[i]);
1071 put_page(pages[i]);
1072 }
1073 mem_cgroup_uncharge_end();
1074 kfree(pages);
1075 goto out;
1076}
1077
1078int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1079 unsigned long address, pmd_t *pmd, pmd_t orig_pmd)
1080{
1081 spinlock_t *ptl;
1082 int ret = 0;
1083 struct page *page = NULL, *new_page;
1084 unsigned long haddr;
1085 unsigned long mmun_start;
1086 unsigned long mmun_end;
1087
1088 ptl = pmd_lockptr(mm, pmd);
1089 VM_BUG_ON(!vma->anon_vma);
1090 haddr = address & HPAGE_PMD_MASK;
1091 if (is_huge_zero_pmd(orig_pmd))
1092 goto alloc;
1093 spin_lock(ptl);
1094 if (unlikely(!pmd_same(*pmd, orig_pmd)))
1095 goto out_unlock;
1096
1097 page = pmd_page(orig_pmd);
1098 VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page);
1099 if (page_mapcount(page) == 1) {
1100 pmd_t entry;
1101 entry = pmd_mkyoung(orig_pmd);
1102 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1103 if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1))
1104 update_mmu_cache_pmd(vma, address, pmd);
1105 ret |= VM_FAULT_WRITE;
1106 goto out_unlock;
1107 }
1108 get_user_huge_page(page);
1109 spin_unlock(ptl);
1110alloc:
1111 if (transparent_hugepage_enabled(vma) &&
1112 !transparent_hugepage_debug_cow())
1113 new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
1114 vma, haddr, numa_node_id(), 0);
1115 else
1116 new_page = NULL;
1117
1118 if (unlikely(!new_page)) {
1119 if (!page) {
1120 split_huge_page_pmd(vma, address, pmd);
1121 ret |= VM_FAULT_FALLBACK;
1122 } else {
1123 ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
1124 pmd, orig_pmd, page, haddr);
1125 if (ret & VM_FAULT_OOM) {
1126 split_huge_page(page);
1127 ret |= VM_FAULT_FALLBACK;
1128 }
1129 put_user_huge_page(page);
1130 }
1131 count_vm_event(THP_FAULT_FALLBACK);
1132 goto out;
1133 }
1134
1135 if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL))) {
1136 put_page(new_page);
1137 if (page) {
1138 split_huge_page(page);
1139 put_user_huge_page(page);
1140 } else
1141 split_huge_page_pmd(vma, address, pmd);
1142 ret |= VM_FAULT_FALLBACK;
1143 count_vm_event(THP_FAULT_FALLBACK);
1144 goto out;
1145 }
1146
1147 count_vm_event(THP_FAULT_ALLOC);
1148
1149 if (!page)
1150 clear_huge_page(new_page, haddr, HPAGE_PMD_NR);
1151 else
1152 copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
1153 __SetPageUptodate(new_page);
1154
1155 mmun_start = haddr;
1156 mmun_end = haddr + HPAGE_PMD_SIZE;
1157 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1158
1159 spin_lock(ptl);
1160 if (page)
1161 put_user_huge_page(page);
1162 if (unlikely(!pmd_same(*pmd, orig_pmd))) {
1163 spin_unlock(ptl);
1164 mem_cgroup_uncharge_page(new_page);
1165 put_page(new_page);
1166 goto out_mn;
1167 } else {
1168 pmd_t entry;
1169 entry = mk_huge_pmd(new_page, vma->vm_page_prot);
1170 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1171 pmdp_clear_flush(vma, haddr, pmd);
1172 page_add_new_anon_rmap(new_page, vma, haddr);
1173 set_pmd_at(mm, haddr, pmd, entry);
1174 update_mmu_cache_pmd(vma, address, pmd);
1175 if (!page) {
1176 add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
1177 put_huge_zero_page();
1178 } else {
1179 VM_BUG_ON_PAGE(!PageHead(page), page);
1180 page_remove_rmap(page);
1181 put_page(page);
1182 }
1183 ret |= VM_FAULT_WRITE;
1184 }
1185 spin_unlock(ptl);
1186out_mn:
1187 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1188out:
1189 return ret;
1190out_unlock:
1191 spin_unlock(ptl);
1192 return ret;
1193}
1194
1195struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
1196 unsigned long addr,
1197 pmd_t *pmd,
1198 unsigned int flags)
1199{
1200 struct mm_struct *mm = vma->vm_mm;
1201 struct page *page = NULL;
1202
1203 assert_spin_locked(pmd_lockptr(mm, pmd));
1204
1205 if (flags & FOLL_WRITE && !pmd_write(*pmd))
1206 goto out;
1207
1208
1209 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1210 return ERR_PTR(-EFAULT);
1211
1212
1213 if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
1214 goto out;
1215
1216 page = pmd_page(*pmd);
1217 VM_BUG_ON_PAGE(!PageHead(page), page);
1218 if (flags & FOLL_TOUCH) {
1219 pmd_t _pmd;
1220
1221
1222
1223
1224
1225
1226
1227
1228 _pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
1229 if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
1230 pmd, _pmd, 1))
1231 update_mmu_cache_pmd(vma, addr, pmd);
1232 }
1233 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1234 if (page->mapping && trylock_page(page)) {
1235 lru_add_drain();
1236 if (page->mapping)
1237 mlock_vma_page(page);
1238 unlock_page(page);
1239 }
1240 }
1241 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1242 VM_BUG_ON_PAGE(!PageCompound(page), page);
1243 if (flags & FOLL_GET)
1244 get_page_foll(page);
1245
1246out:
1247 return page;
1248}
1249
1250
1251int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
1252 unsigned long addr, pmd_t pmd, pmd_t *pmdp)
1253{
1254 spinlock_t *ptl;
1255 struct anon_vma *anon_vma = NULL;
1256 struct page *page;
1257 unsigned long haddr = addr & HPAGE_PMD_MASK;
1258 int page_nid = -1, this_nid = numa_node_id();
1259 int target_nid, last_cpupid = -1;
1260 bool page_locked;
1261 bool migrated = false;
1262 int flags = 0;
1263
1264 ptl = pmd_lock(mm, pmdp);
1265 if (unlikely(!pmd_same(pmd, *pmdp)))
1266 goto out_unlock;
1267
1268
1269
1270
1271
1272
1273 if (unlikely(pmd_trans_migrating(*pmdp))) {
1274 spin_unlock(ptl);
1275 wait_migrate_huge_page(vma->anon_vma, pmdp);
1276 goto out;
1277 }
1278
1279 page = pmd_page(pmd);
1280 BUG_ON(is_huge_zero_page(page));
1281 page_nid = page_to_nid(page);
1282 last_cpupid = page_cpupid_last(page);
1283 count_vm_numa_event(NUMA_HINT_FAULTS);
1284 if (page_nid == this_nid) {
1285 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
1286 flags |= TNF_FAULT_LOCAL;
1287 }
1288
1289
1290
1291
1292
1293
1294 if (!pmd_write(pmd))
1295 flags |= TNF_NO_GROUP;
1296
1297
1298
1299
1300
1301 page_locked = trylock_page(page);
1302 target_nid = mpol_misplaced(page, vma, haddr);
1303 if (target_nid == -1) {
1304
1305 if (page_locked)
1306 goto clear_pmdnuma;
1307 }
1308
1309
1310 if (!page_locked) {
1311 spin_unlock(ptl);
1312 wait_on_page_locked(page);
1313 page_nid = -1;
1314 goto out;
1315 }
1316
1317
1318
1319
1320
1321 get_page(page);
1322 spin_unlock(ptl);
1323 anon_vma = page_lock_anon_vma_read(page);
1324
1325
1326 spin_lock(ptl);
1327 if (unlikely(!pmd_same(pmd, *pmdp))) {
1328 unlock_page(page);
1329 put_page(page);
1330 page_nid = -1;
1331 goto out_unlock;
1332 }
1333
1334
1335 if (unlikely(!anon_vma)) {
1336 put_page(page);
1337 page_nid = -1;
1338 goto clear_pmdnuma;
1339 }
1340
1341
1342
1343
1344
1345 spin_unlock(ptl);
1346 migrated = migrate_misplaced_transhuge_page(mm, vma,
1347 pmdp, pmd, addr, page, target_nid);
1348 if (migrated) {
1349 flags |= TNF_MIGRATED;
1350 page_nid = target_nid;
1351 }
1352
1353 goto out;
1354clear_pmdnuma:
1355 BUG_ON(!PageLocked(page));
1356 pmd = pmd_mknonnuma(pmd);
1357 set_pmd_at(mm, haddr, pmdp, pmd);
1358 VM_BUG_ON(pmd_numa(*pmdp));
1359 update_mmu_cache_pmd(vma, addr, pmdp);
1360 unlock_page(page);
1361out_unlock:
1362 spin_unlock(ptl);
1363
1364out:
1365 if (anon_vma)
1366 page_unlock_anon_vma_read(anon_vma);
1367
1368 if (page_nid != -1)
1369 task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
1370
1371 return 0;
1372}
1373
1374int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1375 pmd_t *pmd, unsigned long addr)
1376{
1377 spinlock_t *ptl;
1378 int ret = 0;
1379
1380 if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
1381 struct page *page;
1382 pgtable_t pgtable;
1383 pmd_t orig_pmd;
1384
1385
1386
1387
1388
1389
1390 orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
1391 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1392 pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
1393 if (is_huge_zero_pmd(orig_pmd)) {
1394 atomic_long_dec(&tlb->mm->nr_ptes);
1395 spin_unlock(ptl);
1396 put_huge_zero_page();
1397 } else {
1398 page = pmd_page(orig_pmd);
1399 page_remove_rmap(page);
1400 VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
1401 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1402 VM_BUG_ON_PAGE(!PageHead(page), page);
1403 atomic_long_dec(&tlb->mm->nr_ptes);
1404 spin_unlock(ptl);
1405 tlb_remove_page(tlb, page);
1406 }
1407 pte_free(tlb->mm, pgtable);
1408 ret = 1;
1409 }
1410 return ret;
1411}
1412
1413int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1414 unsigned long addr, unsigned long end,
1415 unsigned char *vec)
1416{
1417 spinlock_t *ptl;
1418 int ret = 0;
1419
1420 if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
1421
1422
1423
1424
1425 spin_unlock(ptl);
1426 memset(vec, 1, (end - addr) >> PAGE_SHIFT);
1427 ret = 1;
1428 }
1429
1430 return ret;
1431}
1432
1433int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
1434 unsigned long old_addr,
1435 unsigned long new_addr, unsigned long old_end,
1436 pmd_t *old_pmd, pmd_t *new_pmd)
1437{
1438 spinlock_t *old_ptl, *new_ptl;
1439 int ret = 0;
1440 pmd_t pmd;
1441
1442 struct mm_struct *mm = vma->vm_mm;
1443
1444 if ((old_addr & ~HPAGE_PMD_MASK) ||
1445 (new_addr & ~HPAGE_PMD_MASK) ||
1446 old_end - old_addr < HPAGE_PMD_SIZE ||
1447 (new_vma->vm_flags & VM_NOHUGEPAGE))
1448 goto out;
1449
1450
1451
1452
1453
1454 if (WARN_ON(!pmd_none(*new_pmd))) {
1455 VM_BUG_ON(pmd_trans_huge(*new_pmd));
1456 goto out;
1457 }
1458
1459
1460
1461
1462
1463 ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl);
1464 if (ret == 1) {
1465 new_ptl = pmd_lockptr(mm, new_pmd);
1466 if (new_ptl != old_ptl)
1467 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
1468 pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
1469 VM_BUG_ON(!pmd_none(*new_pmd));
1470
1471 if (pmd_move_must_withdraw(new_ptl, old_ptl)) {
1472 pgtable_t pgtable;
1473 pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
1474 pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
1475 }
1476 set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
1477 if (new_ptl != old_ptl)
1478 spin_unlock(new_ptl);
1479 spin_unlock(old_ptl);
1480 }
1481out:
1482 return ret;
1483}
1484
1485
1486
1487
1488
1489
1490
1491int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1492 unsigned long addr, pgprot_t newprot, int prot_numa)
1493{
1494 struct mm_struct *mm = vma->vm_mm;
1495 spinlock_t *ptl;
1496 int ret = 0;
1497
1498 if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
1499 pmd_t entry;
1500 ret = 1;
1501 if (!prot_numa) {
1502 entry = pmdp_get_and_clear(mm, addr, pmd);
1503 if (pmd_numa(entry))
1504 entry = pmd_mknonnuma(entry);
1505 entry = pmd_modify(entry, newprot);
1506 ret = HPAGE_PMD_NR;
1507 set_pmd_at(mm, addr, pmd, entry);
1508 BUG_ON(pmd_write(entry));
1509 } else {
1510 struct page *page = pmd_page(*pmd);
1511
1512
1513
1514
1515
1516
1517
1518 if (!is_huge_zero_page(page) &&
1519 !pmd_numa(*pmd)) {
1520 pmdp_set_numa(mm, addr, pmd);
1521 ret = HPAGE_PMD_NR;
1522 }
1523 }
1524 spin_unlock(ptl);
1525 }
1526
1527 return ret;
1528}
1529
1530
1531
1532
1533
1534
1535
1536
1537int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
1538 spinlock_t **ptl)
1539{
1540 *ptl = pmd_lock(vma->vm_mm, pmd);
1541 if (likely(pmd_trans_huge(*pmd))) {
1542 if (unlikely(pmd_trans_splitting(*pmd))) {
1543 spin_unlock(*ptl);
1544 wait_split_huge_page(vma->anon_vma, pmd);
1545 return -1;
1546 } else {
1547
1548
1549 return 1;
1550 }
1551 }
1552 spin_unlock(*ptl);
1553 return 0;
1554}
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564pmd_t *page_check_address_pmd(struct page *page,
1565 struct mm_struct *mm,
1566 unsigned long address,
1567 enum page_check_address_pmd_flag flag,
1568 spinlock_t **ptl)
1569{
1570 pgd_t *pgd;
1571 pud_t *pud;
1572 pmd_t *pmd;
1573
1574 if (address & ~HPAGE_PMD_MASK)
1575 return NULL;
1576
1577 pgd = pgd_offset(mm, address);
1578 if (!pgd_present(*pgd))
1579 return NULL;
1580 pud = pud_offset(pgd, address);
1581 if (!pud_present(*pud))
1582 return NULL;
1583 pmd = pmd_offset(pud, address);
1584
1585 *ptl = pmd_lock(mm, pmd);
1586 if (!pmd_present(*pmd))
1587 goto unlock;
1588 if (pmd_page(*pmd) != page)
1589 goto unlock;
1590
1591
1592
1593
1594
1595
1596
1597 if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG &&
1598 pmd_trans_splitting(*pmd))
1599 goto unlock;
1600 if (pmd_trans_huge(*pmd)) {
1601 VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG &&
1602 !pmd_trans_splitting(*pmd));
1603 return pmd;
1604 }
1605unlock:
1606 spin_unlock(*ptl);
1607 return NULL;
1608}
1609
1610static int __split_huge_page_splitting(struct page *page,
1611 struct vm_area_struct *vma,
1612 unsigned long address)
1613{
1614 struct mm_struct *mm = vma->vm_mm;
1615 spinlock_t *ptl;
1616 pmd_t *pmd;
1617 int ret = 0;
1618
1619 const unsigned long mmun_start = address;
1620 const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
1621
1622 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1623 pmd = page_check_address_pmd(page, mm, address,
1624 PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl);
1625 if (pmd) {
1626
1627
1628
1629
1630
1631
1632
1633 pmdp_splitting_flush(vma, address, pmd);
1634 ret = 1;
1635 spin_unlock(ptl);
1636 }
1637 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1638
1639 return ret;
1640}
1641
1642static void __split_huge_page_refcount(struct page *page,
1643 struct list_head *list)
1644{
1645 int i;
1646 struct zone *zone = page_zone(page);
1647 struct lruvec *lruvec;
1648 int tail_count = 0;
1649
1650
1651 spin_lock_irq(&zone->lru_lock);
1652 lruvec = mem_cgroup_page_lruvec(page, zone);
1653
1654 compound_lock(page);
1655
1656 mem_cgroup_split_huge_fixup(page);
1657
1658 for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
1659 struct page *page_tail = page + i;
1660
1661
1662 BUG_ON(page_mapcount(page_tail) < 0);
1663 tail_count += page_mapcount(page_tail);
1664
1665 BUG_ON(tail_count < 0);
1666 BUG_ON(atomic_read(&page_tail->_count) != 0);
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680 atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1,
1681 &page_tail->_count);
1682
1683
1684 smp_mb();
1685
1686
1687
1688
1689
1690
1691 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON;
1692 page_tail->flags |= (page->flags &
1693 ((1L << PG_referenced) |
1694 (1L << PG_swapbacked) |
1695 (1L << PG_mlocked) |
1696 (1L << PG_uptodate) |
1697 (1L << PG_active) |
1698 (1L << PG_unevictable)));
1699 page_tail->flags |= (1L << PG_dirty);
1700
1701
1702 smp_wmb();
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718 page_tail->_mapcount = page->_mapcount;
1719
1720 BUG_ON(page_tail->mapping);
1721 page_tail->mapping = page->mapping;
1722
1723 page_tail->index = page->index + i;
1724 page_cpupid_xchg_last(page_tail, page_cpupid_last(page));
1725
1726 BUG_ON(!PageAnon(page_tail));
1727 BUG_ON(!PageUptodate(page_tail));
1728 BUG_ON(!PageDirty(page_tail));
1729 BUG_ON(!PageSwapBacked(page_tail));
1730
1731 lru_add_page_tail(page, page_tail, lruvec, list);
1732 }
1733 atomic_sub(tail_count, &page->_count);
1734 BUG_ON(atomic_read(&page->_count) <= 0);
1735
1736 __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1);
1737
1738 ClearPageCompound(page);
1739 compound_unlock(page);
1740 spin_unlock_irq(&zone->lru_lock);
1741
1742 for (i = 1; i < HPAGE_PMD_NR; i++) {
1743 struct page *page_tail = page + i;
1744 BUG_ON(page_count(page_tail) <= 0);
1745
1746
1747
1748
1749
1750
1751
1752 put_page(page_tail);
1753 }
1754
1755
1756
1757
1758
1759 BUG_ON(page_count(page) <= 0);
1760}
1761
1762static int __split_huge_page_map(struct page *page,
1763 struct vm_area_struct *vma,
1764 unsigned long address)
1765{
1766 struct mm_struct *mm = vma->vm_mm;
1767 spinlock_t *ptl;
1768 pmd_t *pmd, _pmd;
1769 int ret = 0, i;
1770 pgtable_t pgtable;
1771 unsigned long haddr;
1772
1773 pmd = page_check_address_pmd(page, mm, address,
1774 PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl);
1775 if (pmd) {
1776 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1777 pmd_populate(mm, &_pmd, pgtable);
1778
1779 haddr = address;
1780 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1781 pte_t *pte, entry;
1782 BUG_ON(PageCompound(page+i));
1783 entry = mk_pte(page + i, vma->vm_page_prot);
1784 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1785 if (!pmd_write(*pmd))
1786 entry = pte_wrprotect(entry);
1787 else
1788 BUG_ON(page_mapcount(page) != 1);
1789 if (!pmd_young(*pmd))
1790 entry = pte_mkold(entry);
1791 if (pmd_numa(*pmd))
1792 entry = pte_mknuma(entry);
1793 pte = pte_offset_map(&_pmd, haddr);
1794 BUG_ON(!pte_none(*pte));
1795 set_pte_at(mm, haddr, pte, entry);
1796 pte_unmap(pte);
1797 }
1798
1799 smp_wmb();
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826 pmdp_invalidate(vma, address, pmd);
1827 pmd_populate(mm, pmd, pgtable);
1828 ret = 1;
1829 spin_unlock(ptl);
1830 }
1831
1832 return ret;
1833}
1834
1835
1836static void __split_huge_page(struct page *page,
1837 struct anon_vma *anon_vma,
1838 struct list_head *list)
1839{
1840 int mapcount, mapcount2;
1841 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1842 struct anon_vma_chain *avc;
1843
1844 BUG_ON(!PageHead(page));
1845 BUG_ON(PageTail(page));
1846
1847 mapcount = 0;
1848 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1849 struct vm_area_struct *vma = avc->vma;
1850 unsigned long addr = vma_address(page, vma);
1851 BUG_ON(is_vma_temporary_stack(vma));
1852 mapcount += __split_huge_page_splitting(page, vma, addr);
1853 }
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864 if (mapcount != page_mapcount(page)) {
1865 pr_err("mapcount %d page_mapcount %d\n",
1866 mapcount, page_mapcount(page));
1867 BUG();
1868 }
1869
1870 __split_huge_page_refcount(page, list);
1871
1872 mapcount2 = 0;
1873 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1874 struct vm_area_struct *vma = avc->vma;
1875 unsigned long addr = vma_address(page, vma);
1876 BUG_ON(is_vma_temporary_stack(vma));
1877 mapcount2 += __split_huge_page_map(page, vma, addr);
1878 }
1879 if (mapcount != mapcount2) {
1880 pr_err("mapcount %d mapcount2 %d page_mapcount %d\n",
1881 mapcount, mapcount2, page_mapcount(page));
1882 BUG();
1883 }
1884}
1885
1886
1887
1888
1889
1890
1891
1892
1893int split_huge_page_to_list(struct page *page, struct list_head *list)
1894{
1895 struct anon_vma *anon_vma;
1896 int ret = 1;
1897
1898 BUG_ON(is_huge_zero_page(page));
1899 BUG_ON(!PageAnon(page));
1900
1901
1902
1903
1904
1905
1906
1907
1908 anon_vma = page_get_anon_vma(page);
1909 if (!anon_vma)
1910 goto out;
1911 anon_vma_lock_write(anon_vma);
1912
1913 ret = 0;
1914 if (!PageCompound(page))
1915 goto out_unlock;
1916
1917 BUG_ON(!PageSwapBacked(page));
1918 __split_huge_page(page, anon_vma, list);
1919 count_vm_event(THP_SPLIT);
1920
1921 BUG_ON(PageCompound(page));
1922out_unlock:
1923 anon_vma_unlock_write(anon_vma);
1924 put_anon_vma(anon_vma);
1925out:
1926 return ret;
1927}
1928
1929#define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
1930
1931int hugepage_madvise(struct vm_area_struct *vma,
1932 unsigned long *vm_flags, int advice)
1933{
1934 switch (advice) {
1935 case MADV_HUGEPAGE:
1936#ifdef CONFIG_S390
1937
1938
1939
1940
1941
1942 if (mm_has_pgste(vma->vm_mm))
1943 return 0;
1944#endif
1945
1946
1947
1948 if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
1949 return -EINVAL;
1950 *vm_flags &= ~VM_NOHUGEPAGE;
1951 *vm_flags |= VM_HUGEPAGE;
1952
1953
1954
1955
1956
1957 if (unlikely(khugepaged_enter_vma_merge(vma)))
1958 return -ENOMEM;
1959 break;
1960 case MADV_NOHUGEPAGE:
1961
1962
1963
1964 if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP))
1965 return -EINVAL;
1966 *vm_flags &= ~VM_HUGEPAGE;
1967 *vm_flags |= VM_NOHUGEPAGE;
1968
1969
1970
1971
1972
1973 break;
1974 }
1975
1976 return 0;
1977}
1978
1979static int __init khugepaged_slab_init(void)
1980{
1981 mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
1982 sizeof(struct mm_slot),
1983 __alignof__(struct mm_slot), 0, NULL);
1984 if (!mm_slot_cache)
1985 return -ENOMEM;
1986
1987 return 0;
1988}
1989
1990static inline struct mm_slot *alloc_mm_slot(void)
1991{
1992 if (!mm_slot_cache)
1993 return NULL;
1994 return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
1995}
1996
1997static inline void free_mm_slot(struct mm_slot *mm_slot)
1998{
1999 kmem_cache_free(mm_slot_cache, mm_slot);
2000}
2001
2002static struct mm_slot *get_mm_slot(struct mm_struct *mm)
2003{
2004 struct mm_slot *mm_slot;
2005
2006 hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
2007 if (mm == mm_slot->mm)
2008 return mm_slot;
2009
2010 return NULL;
2011}
2012
2013static void insert_to_mm_slots_hash(struct mm_struct *mm,
2014 struct mm_slot *mm_slot)
2015{
2016 mm_slot->mm = mm;
2017 hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
2018}
2019
2020static inline int khugepaged_test_exit(struct mm_struct *mm)
2021{
2022 return atomic_read(&mm->mm_users) == 0;
2023}
2024
2025int __khugepaged_enter(struct mm_struct *mm)
2026{
2027 struct mm_slot *mm_slot;
2028 int wakeup;
2029
2030 mm_slot = alloc_mm_slot();
2031 if (!mm_slot)
2032 return -ENOMEM;
2033
2034
2035 VM_BUG_ON(khugepaged_test_exit(mm));
2036 if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
2037 free_mm_slot(mm_slot);
2038 return 0;
2039 }
2040
2041 spin_lock(&khugepaged_mm_lock);
2042 insert_to_mm_slots_hash(mm, mm_slot);
2043
2044
2045
2046
2047 wakeup = list_empty(&khugepaged_scan.mm_head);
2048 list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
2049 spin_unlock(&khugepaged_mm_lock);
2050
2051 atomic_inc(&mm->mm_count);
2052 if (wakeup)
2053 wake_up_interruptible(&khugepaged_wait);
2054
2055 return 0;
2056}
2057
2058int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
2059{
2060 unsigned long hstart, hend;
2061 if (!vma->anon_vma)
2062
2063
2064
2065
2066 return 0;
2067 if (vma->vm_ops)
2068
2069 return 0;
2070 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
2071 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2072 hend = vma->vm_end & HPAGE_PMD_MASK;
2073 if (hstart < hend)
2074 return khugepaged_enter(vma);
2075 return 0;
2076}
2077
2078void __khugepaged_exit(struct mm_struct *mm)
2079{
2080 struct mm_slot *mm_slot;
2081 int free = 0;
2082
2083 spin_lock(&khugepaged_mm_lock);
2084 mm_slot = get_mm_slot(mm);
2085 if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
2086 hash_del(&mm_slot->hash);
2087 list_del(&mm_slot->mm_node);
2088 free = 1;
2089 }
2090 spin_unlock(&khugepaged_mm_lock);
2091
2092 if (free) {
2093 clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
2094 free_mm_slot(mm_slot);
2095 mmdrop(mm);
2096 } else if (mm_slot) {
2097
2098
2099
2100
2101
2102
2103
2104
2105 down_write(&mm->mmap_sem);
2106 up_write(&mm->mmap_sem);
2107 }
2108}
2109
2110static void release_pte_page(struct page *page)
2111{
2112
2113 dec_zone_page_state(page, NR_ISOLATED_ANON + 0);
2114 unlock_page(page);
2115 putback_lru_page(page);
2116}
2117
2118static void release_pte_pages(pte_t *pte, pte_t *_pte)
2119{
2120 while (--_pte >= pte) {
2121 pte_t pteval = *_pte;
2122 if (!pte_none(pteval))
2123 release_pte_page(pte_page(pteval));
2124 }
2125}
2126
2127static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
2128 unsigned long address,
2129 pte_t *pte)
2130{
2131 struct page *page;
2132 pte_t *_pte;
2133 int referenced = 0, none = 0;
2134 for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
2135 _pte++, address += PAGE_SIZE) {
2136 pte_t pteval = *_pte;
2137 if (pte_none(pteval)) {
2138 if (++none <= khugepaged_max_ptes_none)
2139 continue;
2140 else
2141 goto out;
2142 }
2143 if (!pte_present(pteval) || !pte_write(pteval))
2144 goto out;
2145 page = vm_normal_page(vma, address, pteval);
2146 if (unlikely(!page))
2147 goto out;
2148
2149 VM_BUG_ON_PAGE(PageCompound(page), page);
2150 VM_BUG_ON_PAGE(!PageAnon(page), page);
2151 VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
2152
2153
2154 if (page_count(page) != 1)
2155 goto out;
2156
2157
2158
2159
2160
2161
2162 if (!trylock_page(page))
2163 goto out;
2164
2165
2166
2167
2168 if (isolate_lru_page(page)) {
2169 unlock_page(page);
2170 goto out;
2171 }
2172
2173 inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
2174 VM_BUG_ON_PAGE(!PageLocked(page), page);
2175 VM_BUG_ON_PAGE(PageLRU(page), page);
2176
2177
2178 if (pte_young(pteval) || PageReferenced(page) ||
2179 mmu_notifier_test_young(vma->vm_mm, address))
2180 referenced = 1;
2181 }
2182 if (likely(referenced))
2183 return 1;
2184out:
2185 release_pte_pages(pte, _pte);
2186 return 0;
2187}
2188
2189static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
2190 struct vm_area_struct *vma,
2191 unsigned long address,
2192 spinlock_t *ptl)
2193{
2194 pte_t *_pte;
2195 for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
2196 pte_t pteval = *_pte;
2197 struct page *src_page;
2198
2199 if (pte_none(pteval)) {
2200 clear_user_highpage(page, address);
2201 add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
2202 } else {
2203 src_page = pte_page(pteval);
2204 copy_user_highpage(page, src_page, address, vma);
2205 VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page);
2206 release_pte_page(src_page);
2207
2208
2209
2210
2211
2212 spin_lock(ptl);
2213
2214
2215
2216
2217 pte_clear(vma->vm_mm, address, _pte);
2218 page_remove_rmap(src_page);
2219 spin_unlock(ptl);
2220 free_page_and_swap_cache(src_page);
2221 }
2222
2223 address += PAGE_SIZE;
2224 page++;
2225 }
2226}
2227
2228static void khugepaged_alloc_sleep(void)
2229{
2230 wait_event_freezable_timeout(khugepaged_wait, false,
2231 msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
2232}
2233
2234static int khugepaged_node_load[MAX_NUMNODES];
2235
2236#ifdef CONFIG_NUMA
2237static int khugepaged_find_target_node(void)
2238{
2239 static int last_khugepaged_target_node = NUMA_NO_NODE;
2240 int nid, target_node = 0, max_value = 0;
2241
2242
2243 for (nid = 0; nid < MAX_NUMNODES; nid++)
2244 if (khugepaged_node_load[nid] > max_value) {
2245 max_value = khugepaged_node_load[nid];
2246 target_node = nid;
2247 }
2248
2249
2250 if (target_node <= last_khugepaged_target_node)
2251 for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES;
2252 nid++)
2253 if (max_value == khugepaged_node_load[nid]) {
2254 target_node = nid;
2255 break;
2256 }
2257
2258 last_khugepaged_target_node = target_node;
2259 return target_node;
2260}
2261
2262static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2263{
2264 if (IS_ERR(*hpage)) {
2265 if (!*wait)
2266 return false;
2267
2268 *wait = false;
2269 *hpage = NULL;
2270 khugepaged_alloc_sleep();
2271 } else if (*hpage) {
2272 put_page(*hpage);
2273 *hpage = NULL;
2274 }
2275
2276 return true;
2277}
2278
2279static struct page
2280*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2281 struct vm_area_struct *vma, unsigned long address,
2282 int node)
2283{
2284 VM_BUG_ON_PAGE(*hpage, *hpage);
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295 *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
2296 khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
2297
2298
2299
2300
2301 up_read(&mm->mmap_sem);
2302 if (unlikely(!*hpage)) {
2303 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2304 *hpage = ERR_PTR(-ENOMEM);
2305 return NULL;
2306 }
2307
2308 count_vm_event(THP_COLLAPSE_ALLOC);
2309 return *hpage;
2310}
2311#else
2312static int khugepaged_find_target_node(void)
2313{
2314 return 0;
2315}
2316
2317static inline struct page *alloc_hugepage(int defrag)
2318{
2319 return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
2320 HPAGE_PMD_ORDER);
2321}
2322
2323static struct page *khugepaged_alloc_hugepage(bool *wait)
2324{
2325 struct page *hpage;
2326
2327 do {
2328 hpage = alloc_hugepage(khugepaged_defrag());
2329 if (!hpage) {
2330 count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
2331 if (!*wait)
2332 return NULL;
2333
2334 *wait = false;
2335 khugepaged_alloc_sleep();
2336 } else
2337 count_vm_event(THP_COLLAPSE_ALLOC);
2338 } while (unlikely(!hpage) && likely(khugepaged_enabled()));
2339
2340 return hpage;
2341}
2342
2343static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
2344{
2345 if (!*hpage)
2346 *hpage = khugepaged_alloc_hugepage(wait);
2347
2348 if (unlikely(!*hpage))
2349 return false;
2350
2351 return true;
2352}
2353
2354static struct page
2355*khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm,
2356 struct vm_area_struct *vma, unsigned long address,
2357 int node)
2358{
2359 up_read(&mm->mmap_sem);
2360 VM_BUG_ON(!*hpage);
2361 return *hpage;
2362}
2363#endif
2364
2365static bool hugepage_vma_check(struct vm_area_struct *vma)
2366{
2367 if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
2368 (vma->vm_flags & VM_NOHUGEPAGE))
2369 return false;
2370
2371 if (!vma->anon_vma || vma->vm_ops)
2372 return false;
2373 if (is_vma_temporary_stack(vma))
2374 return false;
2375 VM_BUG_ON(vma->vm_flags & VM_NO_THP);
2376 return true;
2377}
2378
2379static void collapse_huge_page(struct mm_struct *mm,
2380 unsigned long address,
2381 struct page **hpage,
2382 struct vm_area_struct *vma,
2383 int node)
2384{
2385 pmd_t *pmd, _pmd;
2386 pte_t *pte;
2387 pgtable_t pgtable;
2388 struct page *new_page;
2389 spinlock_t *pmd_ptl, *pte_ptl;
2390 int isolated;
2391 unsigned long hstart, hend;
2392 unsigned long mmun_start;
2393 unsigned long mmun_end;
2394
2395 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
2396
2397
2398 new_page = khugepaged_alloc_page(hpage, mm, vma, address, node);
2399 if (!new_page)
2400 return;
2401
2402 if (unlikely(mem_cgroup_charge_anon(new_page, mm, GFP_KERNEL)))
2403 return;
2404
2405
2406
2407
2408
2409
2410 down_write(&mm->mmap_sem);
2411 if (unlikely(khugepaged_test_exit(mm)))
2412 goto out;
2413
2414 vma = find_vma(mm, address);
2415 if (!vma)
2416 goto out;
2417 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2418 hend = vma->vm_end & HPAGE_PMD_MASK;
2419 if (address < hstart || address + HPAGE_PMD_SIZE > hend)
2420 goto out;
2421 if (!hugepage_vma_check(vma))
2422 goto out;
2423 pmd = mm_find_pmd(mm, address);
2424 if (!pmd)
2425 goto out;
2426
2427 anon_vma_lock_write(vma->anon_vma);
2428
2429 pte = pte_offset_map(pmd, address);
2430 pte_ptl = pte_lockptr(mm, pmd);
2431
2432 mmun_start = address;
2433 mmun_end = address + HPAGE_PMD_SIZE;
2434 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2435 pmd_ptl = pmd_lock(mm, pmd);
2436
2437
2438
2439
2440
2441
2442 _pmd = pmdp_clear_flush(vma, address, pmd);
2443 spin_unlock(pmd_ptl);
2444 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2445
2446 spin_lock(pte_ptl);
2447 isolated = __collapse_huge_page_isolate(vma, address, pte);
2448 spin_unlock(pte_ptl);
2449
2450 if (unlikely(!isolated)) {
2451 pte_unmap(pte);
2452 spin_lock(pmd_ptl);
2453 BUG_ON(!pmd_none(*pmd));
2454
2455
2456
2457
2458
2459 pmd_populate(mm, pmd, pmd_pgtable(_pmd));
2460 spin_unlock(pmd_ptl);
2461 anon_vma_unlock_write(vma->anon_vma);
2462 goto out;
2463 }
2464
2465
2466
2467
2468
2469 anon_vma_unlock_write(vma->anon_vma);
2470
2471 __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl);
2472 pte_unmap(pte);
2473 __SetPageUptodate(new_page);
2474 pgtable = pmd_pgtable(_pmd);
2475
2476 _pmd = mk_huge_pmd(new_page, vma->vm_page_prot);
2477 _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
2478
2479
2480
2481
2482
2483
2484 smp_wmb();
2485
2486 spin_lock(pmd_ptl);
2487 BUG_ON(!pmd_none(*pmd));
2488 page_add_new_anon_rmap(new_page, vma, address);
2489 pgtable_trans_huge_deposit(mm, pmd, pgtable);
2490 set_pmd_at(mm, address, pmd, _pmd);
2491 update_mmu_cache_pmd(vma, address, pmd);
2492 spin_unlock(pmd_ptl);
2493
2494 *hpage = NULL;
2495
2496 khugepaged_pages_collapsed++;
2497out_up_write:
2498 up_write(&mm->mmap_sem);
2499 return;
2500
2501out:
2502 mem_cgroup_uncharge_page(new_page);
2503 goto out_up_write;
2504}
2505
2506static int khugepaged_scan_pmd(struct mm_struct *mm,
2507 struct vm_area_struct *vma,
2508 unsigned long address,
2509 struct page **hpage)
2510{
2511 pmd_t *pmd;
2512 pte_t *pte, *_pte;
2513 int ret = 0, referenced = 0, none = 0;
2514 struct page *page;
2515 unsigned long _address;
2516 spinlock_t *ptl;
2517 int node = NUMA_NO_NODE;
2518
2519 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
2520
2521 pmd = mm_find_pmd(mm, address);
2522 if (!pmd)
2523 goto out;
2524
2525 memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
2526 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2527 for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
2528 _pte++, _address += PAGE_SIZE) {
2529 pte_t pteval = *_pte;
2530 if (pte_none(pteval)) {
2531 if (++none <= khugepaged_max_ptes_none)
2532 continue;
2533 else
2534 goto out_unmap;
2535 }
2536 if (!pte_present(pteval) || !pte_write(pteval))
2537 goto out_unmap;
2538 page = vm_normal_page(vma, _address, pteval);
2539 if (unlikely(!page))
2540 goto out_unmap;
2541
2542
2543
2544
2545
2546
2547 node = page_to_nid(page);
2548 khugepaged_node_load[node]++;
2549 VM_BUG_ON_PAGE(PageCompound(page), page);
2550 if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
2551 goto out_unmap;
2552
2553 if (page_count(page) != 1)
2554 goto out_unmap;
2555 if (pte_young(pteval) || PageReferenced(page) ||
2556 mmu_notifier_test_young(vma->vm_mm, address))
2557 referenced = 1;
2558 }
2559 if (referenced)
2560 ret = 1;
2561out_unmap:
2562 pte_unmap_unlock(pte, ptl);
2563 if (ret) {
2564 node = khugepaged_find_target_node();
2565
2566 collapse_huge_page(mm, address, hpage, vma, node);
2567 }
2568out:
2569 return ret;
2570}
2571
2572static void collect_mm_slot(struct mm_slot *mm_slot)
2573{
2574 struct mm_struct *mm = mm_slot->mm;
2575
2576 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
2577
2578 if (khugepaged_test_exit(mm)) {
2579
2580 hash_del(&mm_slot->hash);
2581 list_del(&mm_slot->mm_node);
2582
2583
2584
2585
2586
2587
2588
2589
2590 free_mm_slot(mm_slot);
2591 mmdrop(mm);
2592 }
2593}
2594
2595static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
2596 struct page **hpage)
2597 __releases(&khugepaged_mm_lock)
2598 __acquires(&khugepaged_mm_lock)
2599{
2600 struct mm_slot *mm_slot;
2601 struct mm_struct *mm;
2602 struct vm_area_struct *vma;
2603 int progress = 0;
2604
2605 VM_BUG_ON(!pages);
2606 VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
2607
2608 if (khugepaged_scan.mm_slot)
2609 mm_slot = khugepaged_scan.mm_slot;
2610 else {
2611 mm_slot = list_entry(khugepaged_scan.mm_head.next,
2612 struct mm_slot, mm_node);
2613 khugepaged_scan.address = 0;
2614 khugepaged_scan.mm_slot = mm_slot;
2615 }
2616 spin_unlock(&khugepaged_mm_lock);
2617
2618 mm = mm_slot->mm;
2619 down_read(&mm->mmap_sem);
2620 if (unlikely(khugepaged_test_exit(mm)))
2621 vma = NULL;
2622 else
2623 vma = find_vma(mm, khugepaged_scan.address);
2624
2625 progress++;
2626 for (; vma; vma = vma->vm_next) {
2627 unsigned long hstart, hend;
2628
2629 cond_resched();
2630 if (unlikely(khugepaged_test_exit(mm))) {
2631 progress++;
2632 break;
2633 }
2634 if (!hugepage_vma_check(vma)) {
2635skip:
2636 progress++;
2637 continue;
2638 }
2639 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
2640 hend = vma->vm_end & HPAGE_PMD_MASK;
2641 if (hstart >= hend)
2642 goto skip;
2643 if (khugepaged_scan.address > hend)
2644 goto skip;
2645 if (khugepaged_scan.address < hstart)
2646 khugepaged_scan.address = hstart;
2647 VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK);
2648
2649 while (khugepaged_scan.address < hend) {
2650 int ret;
2651 cond_resched();
2652 if (unlikely(khugepaged_test_exit(mm)))
2653 goto breakouterloop;
2654
2655 VM_BUG_ON(khugepaged_scan.address < hstart ||
2656 khugepaged_scan.address + HPAGE_PMD_SIZE >
2657 hend);
2658 ret = khugepaged_scan_pmd(mm, vma,
2659 khugepaged_scan.address,
2660 hpage);
2661
2662 khugepaged_scan.address += HPAGE_PMD_SIZE;
2663 progress += HPAGE_PMD_NR;
2664 if (ret)
2665
2666 goto breakouterloop_mmap_sem;
2667 if (progress >= pages)
2668 goto breakouterloop;
2669 }
2670 }
2671breakouterloop:
2672 up_read(&mm->mmap_sem);
2673breakouterloop_mmap_sem:
2674
2675 spin_lock(&khugepaged_mm_lock);
2676 VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot);
2677
2678
2679
2680
2681 if (khugepaged_test_exit(mm) || !vma) {
2682
2683
2684
2685
2686
2687 if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
2688 khugepaged_scan.mm_slot = list_entry(
2689 mm_slot->mm_node.next,
2690 struct mm_slot, mm_node);
2691 khugepaged_scan.address = 0;
2692 } else {
2693 khugepaged_scan.mm_slot = NULL;
2694 khugepaged_full_scans++;
2695 }
2696
2697 collect_mm_slot(mm_slot);
2698 }
2699
2700 return progress;
2701}
2702
2703static int khugepaged_has_work(void)
2704{
2705 return !list_empty(&khugepaged_scan.mm_head) &&
2706 khugepaged_enabled();
2707}
2708
2709static int khugepaged_wait_event(void)
2710{
2711 return !list_empty(&khugepaged_scan.mm_head) ||
2712 kthread_should_stop();
2713}
2714
2715static void khugepaged_do_scan(void)
2716{
2717 struct page *hpage = NULL;
2718 unsigned int progress = 0, pass_through_head = 0;
2719 unsigned int pages = khugepaged_pages_to_scan;
2720 bool wait = true;
2721
2722 barrier();
2723
2724 while (progress < pages) {
2725 if (!khugepaged_prealloc_page(&hpage, &wait))
2726 break;
2727
2728 cond_resched();
2729
2730 if (unlikely(kthread_should_stop() || freezing(current)))
2731 break;
2732
2733 spin_lock(&khugepaged_mm_lock);
2734 if (!khugepaged_scan.mm_slot)
2735 pass_through_head++;
2736 if (khugepaged_has_work() &&
2737 pass_through_head < 2)
2738 progress += khugepaged_scan_mm_slot(pages - progress,
2739 &hpage);
2740 else
2741 progress = pages;
2742 spin_unlock(&khugepaged_mm_lock);
2743 }
2744
2745 if (!IS_ERR_OR_NULL(hpage))
2746 put_page(hpage);
2747}
2748
2749static void khugepaged_wait_work(void)
2750{
2751 try_to_freeze();
2752
2753 if (khugepaged_has_work()) {
2754 if (!khugepaged_scan_sleep_millisecs)
2755 return;
2756
2757 wait_event_freezable_timeout(khugepaged_wait,
2758 kthread_should_stop(),
2759 msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
2760 return;
2761 }
2762
2763 if (khugepaged_enabled())
2764 wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
2765}
2766
2767static int khugepaged(void *none)
2768{
2769 struct mm_slot *mm_slot;
2770
2771 set_freezable();
2772 set_user_nice(current, MAX_NICE);
2773
2774 while (!kthread_should_stop()) {
2775 khugepaged_do_scan();
2776 khugepaged_wait_work();
2777 }
2778
2779 spin_lock(&khugepaged_mm_lock);
2780 mm_slot = khugepaged_scan.mm_slot;
2781 khugepaged_scan.mm_slot = NULL;
2782 if (mm_slot)
2783 collect_mm_slot(mm_slot);
2784 spin_unlock(&khugepaged_mm_lock);
2785 return 0;
2786}
2787
2788static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
2789 unsigned long haddr, pmd_t *pmd)
2790{
2791 struct mm_struct *mm = vma->vm_mm;
2792 pgtable_t pgtable;
2793 pmd_t _pmd;
2794 int i;
2795
2796 pmdp_clear_flush(vma, haddr, pmd);
2797
2798
2799 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
2800 pmd_populate(mm, &_pmd, pgtable);
2801
2802 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
2803 pte_t *pte, entry;
2804 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
2805 entry = pte_mkspecial(entry);
2806 pte = pte_offset_map(&_pmd, haddr);
2807 VM_BUG_ON(!pte_none(*pte));
2808 set_pte_at(mm, haddr, pte, entry);
2809 pte_unmap(pte);
2810 }
2811 smp_wmb();
2812 pmd_populate(mm, pmd, pgtable);
2813 put_huge_zero_page();
2814}
2815
2816void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
2817 pmd_t *pmd)
2818{
2819 spinlock_t *ptl;
2820 struct page *page;
2821 struct mm_struct *mm = vma->vm_mm;
2822 unsigned long haddr = address & HPAGE_PMD_MASK;
2823 unsigned long mmun_start;
2824 unsigned long mmun_end;
2825
2826 BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE);
2827
2828 mmun_start = haddr;
2829 mmun_end = haddr + HPAGE_PMD_SIZE;
2830again:
2831 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2832 ptl = pmd_lock(mm, pmd);
2833 if (unlikely(!pmd_trans_huge(*pmd))) {
2834 spin_unlock(ptl);
2835 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2836 return;
2837 }
2838 if (is_huge_zero_pmd(*pmd)) {
2839 __split_huge_zero_page_pmd(vma, haddr, pmd);
2840 spin_unlock(ptl);
2841 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2842 return;
2843 }
2844 page = pmd_page(*pmd);
2845 VM_BUG_ON_PAGE(!page_count(page), page);
2846 get_page(page);
2847 spin_unlock(ptl);
2848 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2849
2850 split_huge_page(page);
2851
2852 put_page(page);
2853
2854
2855
2856
2857
2858
2859 if (unlikely(pmd_trans_huge(*pmd)))
2860 goto again;
2861}
2862
2863void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
2864 pmd_t *pmd)
2865{
2866 struct vm_area_struct *vma;
2867
2868 vma = find_vma(mm, address);
2869 BUG_ON(vma == NULL);
2870 split_huge_page_pmd(vma, address, pmd);
2871}
2872
2873static void split_huge_page_address(struct mm_struct *mm,
2874 unsigned long address)
2875{
2876 pgd_t *pgd;
2877 pud_t *pud;
2878 pmd_t *pmd;
2879
2880 VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
2881
2882 pgd = pgd_offset(mm, address);
2883 if (!pgd_present(*pgd))
2884 return;
2885
2886 pud = pud_offset(pgd, address);
2887 if (!pud_present(*pud))
2888 return;
2889
2890 pmd = pmd_offset(pud, address);
2891 if (!pmd_present(*pmd))
2892 return;
2893
2894
2895
2896
2897 split_huge_page_pmd_mm(mm, address, pmd);
2898}
2899
2900void __vma_adjust_trans_huge(struct vm_area_struct *vma,
2901 unsigned long start,
2902 unsigned long end,
2903 long adjust_next)
2904{
2905
2906
2907
2908
2909
2910 if (start & ~HPAGE_PMD_MASK &&
2911 (start & HPAGE_PMD_MASK) >= vma->vm_start &&
2912 (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2913 split_huge_page_address(vma->vm_mm, start);
2914
2915
2916
2917
2918
2919
2920 if (end & ~HPAGE_PMD_MASK &&
2921 (end & HPAGE_PMD_MASK) >= vma->vm_start &&
2922 (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2923 split_huge_page_address(vma->vm_mm, end);
2924
2925
2926
2927
2928
2929
2930 if (adjust_next > 0) {
2931 struct vm_area_struct *next = vma->vm_next;
2932 unsigned long nstart = next->vm_start;
2933 nstart += adjust_next << PAGE_SHIFT;
2934 if (nstart & ~HPAGE_PMD_MASK &&
2935 (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
2936 (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
2937 split_huge_page_address(next->vm_mm, nstart);
2938 }
2939}
2940