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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/swapops.h>
20#include <linux/dax.h>
21#include <linux/khugepaged.h>
22#include <linux/freezer.h>
23#include <linux/pfn_t.h>
24#include <linux/mman.h>
25#include <linux/memremap.h>
26#include <linux/pagemap.h>
27#include <linux/debugfs.h>
28#include <linux/migrate.h>
29#include <linux/hashtable.h>
30#include <linux/userfaultfd_k.h>
31#include <linux/page_idle.h>
32#include <linux/shmem_fs.h>
33
34#include <asm/tlb.h>
35#include <asm/pgalloc.h>
36#include "internal.h"
37
38
39
40
41
42
43
44
45
46unsigned long transparent_hugepage_flags __read_mostly =
47#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
48 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
49#endif
50#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
51 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
52#endif
53 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)|
54 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
55 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
56
57static struct shrinker deferred_split_shrinker;
58
59static atomic_t huge_zero_refcount;
60struct page *huge_zero_page __read_mostly;
61
62static struct page *get_huge_zero_page(void)
63{
64 struct page *zero_page;
65retry:
66 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
67 return READ_ONCE(huge_zero_page);
68
69 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
70 HPAGE_PMD_ORDER);
71 if (!zero_page) {
72 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
73 return NULL;
74 }
75 count_vm_event(THP_ZERO_PAGE_ALLOC);
76 preempt_disable();
77 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
78 preempt_enable();
79 __free_pages(zero_page, compound_order(zero_page));
80 goto retry;
81 }
82
83
84 atomic_set(&huge_zero_refcount, 2);
85 preempt_enable();
86 return READ_ONCE(huge_zero_page);
87}
88
89static void put_huge_zero_page(void)
90{
91
92
93
94
95 BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
96}
97
98struct page *mm_get_huge_zero_page(struct mm_struct *mm)
99{
100 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
101 return READ_ONCE(huge_zero_page);
102
103 if (!get_huge_zero_page())
104 return NULL;
105
106 if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
107 put_huge_zero_page();
108
109 return READ_ONCE(huge_zero_page);
110}
111
112void mm_put_huge_zero_page(struct mm_struct *mm)
113{
114 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
115 put_huge_zero_page();
116}
117
118static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink,
119 struct shrink_control *sc)
120{
121
122 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
123}
124
125static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
126 struct shrink_control *sc)
127{
128 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
129 struct page *zero_page = xchg(&huge_zero_page, NULL);
130 BUG_ON(zero_page == NULL);
131 __free_pages(zero_page, compound_order(zero_page));
132 return HPAGE_PMD_NR;
133 }
134
135 return 0;
136}
137
138static struct shrinker huge_zero_page_shrinker = {
139 .count_objects = shrink_huge_zero_page_count,
140 .scan_objects = shrink_huge_zero_page_scan,
141 .seeks = DEFAULT_SEEKS,
142};
143
144#ifdef CONFIG_SYSFS
145
146static ssize_t triple_flag_store(struct kobject *kobj,
147 struct kobj_attribute *attr,
148 const char *buf, size_t count,
149 enum transparent_hugepage_flag enabled,
150 enum transparent_hugepage_flag deferred,
151 enum transparent_hugepage_flag req_madv)
152{
153 if (!memcmp("defer", buf,
154 min(sizeof("defer")-1, count))) {
155 if (enabled == deferred)
156 return -EINVAL;
157 clear_bit(enabled, &transparent_hugepage_flags);
158 clear_bit(req_madv, &transparent_hugepage_flags);
159 set_bit(deferred, &transparent_hugepage_flags);
160 } else if (!memcmp("always", buf,
161 min(sizeof("always")-1, count))) {
162 clear_bit(deferred, &transparent_hugepage_flags);
163 clear_bit(req_madv, &transparent_hugepage_flags);
164 set_bit(enabled, &transparent_hugepage_flags);
165 } else if (!memcmp("madvise", buf,
166 min(sizeof("madvise")-1, count))) {
167 clear_bit(enabled, &transparent_hugepage_flags);
168 clear_bit(deferred, &transparent_hugepage_flags);
169 set_bit(req_madv, &transparent_hugepage_flags);
170 } else if (!memcmp("never", buf,
171 min(sizeof("never")-1, count))) {
172 clear_bit(enabled, &transparent_hugepage_flags);
173 clear_bit(req_madv, &transparent_hugepage_flags);
174 clear_bit(deferred, &transparent_hugepage_flags);
175 } else
176 return -EINVAL;
177
178 return count;
179}
180
181static ssize_t enabled_show(struct kobject *kobj,
182 struct kobj_attribute *attr, char *buf)
183{
184 if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags))
185 return sprintf(buf, "[always] madvise never\n");
186 else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags))
187 return sprintf(buf, "always [madvise] never\n");
188 else
189 return sprintf(buf, "always madvise [never]\n");
190}
191
192static ssize_t enabled_store(struct kobject *kobj,
193 struct kobj_attribute *attr,
194 const char *buf, size_t count)
195{
196 ssize_t ret;
197
198 ret = triple_flag_store(kobj, attr, buf, count,
199 TRANSPARENT_HUGEPAGE_FLAG,
200 TRANSPARENT_HUGEPAGE_FLAG,
201 TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
202
203 if (ret > 0) {
204 int err = start_stop_khugepaged();
205 if (err)
206 ret = err;
207 }
208
209 return ret;
210}
211static struct kobj_attribute enabled_attr =
212 __ATTR(enabled, 0644, enabled_show, enabled_store);
213
214ssize_t single_hugepage_flag_show(struct kobject *kobj,
215 struct kobj_attribute *attr, char *buf,
216 enum transparent_hugepage_flag flag)
217{
218 return sprintf(buf, "%d\n",
219 !!test_bit(flag, &transparent_hugepage_flags));
220}
221
222ssize_t single_hugepage_flag_store(struct kobject *kobj,
223 struct kobj_attribute *attr,
224 const char *buf, size_t count,
225 enum transparent_hugepage_flag flag)
226{
227 unsigned long value;
228 int ret;
229
230 ret = kstrtoul(buf, 10, &value);
231 if (ret < 0)
232 return ret;
233 if (value > 1)
234 return -EINVAL;
235
236 if (value)
237 set_bit(flag, &transparent_hugepage_flags);
238 else
239 clear_bit(flag, &transparent_hugepage_flags);
240
241 return count;
242}
243
244
245
246
247
248
249static ssize_t defrag_show(struct kobject *kobj,
250 struct kobj_attribute *attr, char *buf)
251{
252 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags))
253 return sprintf(buf, "[always] defer madvise never\n");
254 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags))
255 return sprintf(buf, "always [defer] madvise never\n");
256 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags))
257 return sprintf(buf, "always defer [madvise] never\n");
258 else
259 return sprintf(buf, "always defer madvise [never]\n");
260
261}
262static ssize_t defrag_store(struct kobject *kobj,
263 struct kobj_attribute *attr,
264 const char *buf, size_t count)
265{
266 return triple_flag_store(kobj, attr, buf, count,
267 TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
268 TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
269 TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG);
270}
271static struct kobj_attribute defrag_attr =
272 __ATTR(defrag, 0644, defrag_show, defrag_store);
273
274static ssize_t use_zero_page_show(struct kobject *kobj,
275 struct kobj_attribute *attr, char *buf)
276{
277 return single_hugepage_flag_show(kobj, attr, buf,
278 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
279}
280static ssize_t use_zero_page_store(struct kobject *kobj,
281 struct kobj_attribute *attr, const char *buf, size_t count)
282{
283 return single_hugepage_flag_store(kobj, attr, buf, count,
284 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
285}
286static struct kobj_attribute use_zero_page_attr =
287 __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
288#ifdef CONFIG_DEBUG_VM
289static ssize_t debug_cow_show(struct kobject *kobj,
290 struct kobj_attribute *attr, char *buf)
291{
292 return single_hugepage_flag_show(kobj, attr, buf,
293 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
294}
295static ssize_t debug_cow_store(struct kobject *kobj,
296 struct kobj_attribute *attr,
297 const char *buf, size_t count)
298{
299 return single_hugepage_flag_store(kobj, attr, buf, count,
300 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
301}
302static struct kobj_attribute debug_cow_attr =
303 __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store);
304#endif
305
306static struct attribute *hugepage_attr[] = {
307 &enabled_attr.attr,
308 &defrag_attr.attr,
309 &use_zero_page_attr.attr,
310#if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE)
311 &shmem_enabled_attr.attr,
312#endif
313#ifdef CONFIG_DEBUG_VM
314 &debug_cow_attr.attr,
315#endif
316 NULL,
317};
318
319static struct attribute_group hugepage_attr_group = {
320 .attrs = hugepage_attr,
321};
322
323static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
324{
325 int err;
326
327 *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
328 if (unlikely(!*hugepage_kobj)) {
329 pr_err("failed to create transparent hugepage kobject\n");
330 return -ENOMEM;
331 }
332
333 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
334 if (err) {
335 pr_err("failed to register transparent hugepage group\n");
336 goto delete_obj;
337 }
338
339 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
340 if (err) {
341 pr_err("failed to register transparent hugepage group\n");
342 goto remove_hp_group;
343 }
344
345 return 0;
346
347remove_hp_group:
348 sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group);
349delete_obj:
350 kobject_put(*hugepage_kobj);
351 return err;
352}
353
354static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj)
355{
356 sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
357 sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
358 kobject_put(hugepage_kobj);
359}
360#else
361static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj)
362{
363 return 0;
364}
365
366static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj)
367{
368}
369#endif
370
371static int __init hugepage_init(void)
372{
373 int err;
374 struct kobject *hugepage_kobj;
375
376 if (!has_transparent_hugepage()) {
377 transparent_hugepage_flags = 0;
378 return -EINVAL;
379 }
380
381
382
383
384 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
385
386
387
388
389 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2);
390
391 err = hugepage_init_sysfs(&hugepage_kobj);
392 if (err)
393 goto err_sysfs;
394
395 err = khugepaged_init();
396 if (err)
397 goto err_slab;
398
399 err = register_shrinker(&huge_zero_page_shrinker);
400 if (err)
401 goto err_hzp_shrinker;
402 err = register_shrinker(&deferred_split_shrinker);
403 if (err)
404 goto err_split_shrinker;
405
406
407
408
409
410
411 if (totalram_pages < (512 << (20 - PAGE_SHIFT))) {
412 transparent_hugepage_flags = 0;
413 return 0;
414 }
415
416 err = start_stop_khugepaged();
417 if (err)
418 goto err_khugepaged;
419
420 return 0;
421err_khugepaged:
422 unregister_shrinker(&deferred_split_shrinker);
423err_split_shrinker:
424 unregister_shrinker(&huge_zero_page_shrinker);
425err_hzp_shrinker:
426 khugepaged_destroy();
427err_slab:
428 hugepage_exit_sysfs(hugepage_kobj);
429err_sysfs:
430 return err;
431}
432subsys_initcall(hugepage_init);
433
434static int __init setup_transparent_hugepage(char *str)
435{
436 int ret = 0;
437 if (!str)
438 goto out;
439 if (!strcmp(str, "always")) {
440 set_bit(TRANSPARENT_HUGEPAGE_FLAG,
441 &transparent_hugepage_flags);
442 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
443 &transparent_hugepage_flags);
444 ret = 1;
445 } else if (!strcmp(str, "madvise")) {
446 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
447 &transparent_hugepage_flags);
448 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
449 &transparent_hugepage_flags);
450 ret = 1;
451 } else if (!strcmp(str, "never")) {
452 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
453 &transparent_hugepage_flags);
454 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
455 &transparent_hugepage_flags);
456 ret = 1;
457 }
458out:
459 if (!ret)
460 pr_warn("transparent_hugepage= cannot parse, ignored\n");
461 return ret;
462}
463__setup("transparent_hugepage=", setup_transparent_hugepage);
464
465pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
466{
467 if (likely(vma->vm_flags & VM_WRITE))
468 pmd = pmd_mkwrite(pmd);
469 return pmd;
470}
471
472static inline struct list_head *page_deferred_list(struct page *page)
473{
474
475
476
477
478 return (struct list_head *)&page[2].mapping;
479}
480
481void prep_transhuge_page(struct page *page)
482{
483
484
485
486
487
488 INIT_LIST_HEAD(page_deferred_list(page));
489 set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);
490}
491
492unsigned long __thp_get_unmapped_area(struct file *filp, unsigned long len,
493 loff_t off, unsigned long flags, unsigned long size)
494{
495 unsigned long addr;
496 loff_t off_end = off + len;
497 loff_t off_align = round_up(off, size);
498 unsigned long len_pad;
499
500 if (off_end <= off_align || (off_end - off_align) < size)
501 return 0;
502
503 len_pad = len + size;
504 if (len_pad < len || (off + len_pad) < off)
505 return 0;
506
507 addr = current->mm->get_unmapped_area(filp, 0, len_pad,
508 off >> PAGE_SHIFT, flags);
509 if (IS_ERR_VALUE(addr))
510 return 0;
511
512 addr += (off - addr) & (size - 1);
513 return addr;
514}
515
516unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
517 unsigned long len, unsigned long pgoff, unsigned long flags)
518{
519 loff_t off = (loff_t)pgoff << PAGE_SHIFT;
520
521 if (addr)
522 goto out;
523 if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD))
524 goto out;
525
526 addr = __thp_get_unmapped_area(filp, len, off, flags, PMD_SIZE);
527 if (addr)
528 return addr;
529
530 out:
531 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
532}
533EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
534
535static int __do_huge_pmd_anonymous_page(struct fault_env *fe, struct page *page,
536 gfp_t gfp)
537{
538 struct vm_area_struct *vma = fe->vma;
539 struct mem_cgroup *memcg;
540 pgtable_t pgtable;
541 unsigned long haddr = fe->address & HPAGE_PMD_MASK;
542
543 VM_BUG_ON_PAGE(!PageCompound(page), page);
544
545 if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) {
546 put_page(page);
547 count_vm_event(THP_FAULT_FALLBACK);
548 return VM_FAULT_FALLBACK;
549 }
550
551 pgtable = pte_alloc_one(vma->vm_mm, haddr);
552 if (unlikely(!pgtable)) {
553 mem_cgroup_cancel_charge(page, memcg, true);
554 put_page(page);
555 return VM_FAULT_OOM;
556 }
557
558 clear_huge_page(page, haddr, HPAGE_PMD_NR);
559
560
561
562
563
564 __SetPageUptodate(page);
565
566 fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
567 if (unlikely(!pmd_none(*fe->pmd))) {
568 spin_unlock(fe->ptl);
569 mem_cgroup_cancel_charge(page, memcg, true);
570 put_page(page);
571 pte_free(vma->vm_mm, pgtable);
572 } else {
573 pmd_t entry;
574
575
576 if (userfaultfd_missing(vma)) {
577 int ret;
578
579 spin_unlock(fe->ptl);
580 mem_cgroup_cancel_charge(page, memcg, true);
581 put_page(page);
582 pte_free(vma->vm_mm, pgtable);
583 ret = handle_userfault(fe, VM_UFFD_MISSING);
584 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
585 return ret;
586 }
587
588 entry = mk_huge_pmd(page, vma->vm_page_prot);
589 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
590 page_add_new_anon_rmap(page, vma, haddr, true);
591 mem_cgroup_commit_charge(page, memcg, false, true);
592 lru_cache_add_active_or_unevictable(page, vma);
593 pgtable_trans_huge_deposit(vma->vm_mm, fe->pmd, pgtable);
594 set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
595 add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
596 atomic_long_inc(&vma->vm_mm->nr_ptes);
597 spin_unlock(fe->ptl);
598 count_vm_event(THP_FAULT_ALLOC);
599 }
600
601 return 0;
602}
603
604
605
606
607
608
609
610static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma)
611{
612 bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE);
613
614 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
615 &transparent_hugepage_flags) && vma_madvised)
616 return GFP_TRANSHUGE;
617 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
618 &transparent_hugepage_flags))
619 return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM;
620 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
621 &transparent_hugepage_flags))
622 return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY);
623
624 return GFP_TRANSHUGE_LIGHT;
625}
626
627
628static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
629 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
630 struct page *zero_page)
631{
632 pmd_t entry;
633 if (!pmd_none(*pmd))
634 return false;
635 entry = mk_pmd(zero_page, vma->vm_page_prot);
636 entry = pmd_mkhuge(entry);
637 if (pgtable)
638 pgtable_trans_huge_deposit(mm, pmd, pgtable);
639 set_pmd_at(mm, haddr, pmd, entry);
640 atomic_long_inc(&mm->nr_ptes);
641 return true;
642}
643
644int do_huge_pmd_anonymous_page(struct fault_env *fe)
645{
646 struct vm_area_struct *vma = fe->vma;
647 gfp_t gfp;
648 struct page *page;
649 unsigned long haddr = fe->address & HPAGE_PMD_MASK;
650
651 if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
652 return VM_FAULT_FALLBACK;
653 if (unlikely(anon_vma_prepare(vma)))
654 return VM_FAULT_OOM;
655 if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
656 return VM_FAULT_OOM;
657 if (!(fe->flags & FAULT_FLAG_WRITE) &&
658 !mm_forbids_zeropage(vma->vm_mm) &&
659 transparent_hugepage_use_zero_page()) {
660 pgtable_t pgtable;
661 struct page *zero_page;
662 bool set;
663 int ret;
664 pgtable = pte_alloc_one(vma->vm_mm, haddr);
665 if (unlikely(!pgtable))
666 return VM_FAULT_OOM;
667 zero_page = mm_get_huge_zero_page(vma->vm_mm);
668 if (unlikely(!zero_page)) {
669 pte_free(vma->vm_mm, pgtable);
670 count_vm_event(THP_FAULT_FALLBACK);
671 return VM_FAULT_FALLBACK;
672 }
673 fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
674 ret = 0;
675 set = false;
676 if (pmd_none(*fe->pmd)) {
677 if (userfaultfd_missing(vma)) {
678 spin_unlock(fe->ptl);
679 ret = handle_userfault(fe, VM_UFFD_MISSING);
680 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
681 } else {
682 set_huge_zero_page(pgtable, vma->vm_mm, vma,
683 haddr, fe->pmd, zero_page);
684 spin_unlock(fe->ptl);
685 set = true;
686 }
687 } else
688 spin_unlock(fe->ptl);
689 if (!set)
690 pte_free(vma->vm_mm, pgtable);
691 return ret;
692 }
693 gfp = alloc_hugepage_direct_gfpmask(vma);
694 page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
695 if (unlikely(!page)) {
696 count_vm_event(THP_FAULT_FALLBACK);
697 return VM_FAULT_FALLBACK;
698 }
699 prep_transhuge_page(page);
700 return __do_huge_pmd_anonymous_page(fe, page, gfp);
701}
702
703static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
704 pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write)
705{
706 struct mm_struct *mm = vma->vm_mm;
707 pmd_t entry;
708 spinlock_t *ptl;
709
710 ptl = pmd_lock(mm, pmd);
711 entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
712 if (pfn_t_devmap(pfn))
713 entry = pmd_mkdevmap(entry);
714 if (write) {
715 entry = pmd_mkyoung(pmd_mkdirty(entry));
716 entry = maybe_pmd_mkwrite(entry, vma);
717 }
718 set_pmd_at(mm, addr, pmd, entry);
719 update_mmu_cache_pmd(vma, addr, pmd);
720 spin_unlock(ptl);
721}
722
723int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
724 pmd_t *pmd, pfn_t pfn, bool write)
725{
726 pgprot_t pgprot = vma->vm_page_prot;
727
728
729
730
731
732 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
733 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
734 (VM_PFNMAP|VM_MIXEDMAP));
735 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
736 BUG_ON(!pfn_t_devmap(pfn));
737
738 if (addr < vma->vm_start || addr >= vma->vm_end)
739 return VM_FAULT_SIGBUS;
740 if (track_pfn_insert(vma, &pgprot, pfn))
741 return VM_FAULT_SIGBUS;
742 insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
743 return VM_FAULT_NOPAGE;
744}
745EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);
746
747static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
748 pmd_t *pmd)
749{
750 pmd_t _pmd;
751
752
753
754
755
756
757
758
759 _pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
760 if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
761 pmd, _pmd, 1))
762 update_mmu_cache_pmd(vma, addr, pmd);
763}
764
765struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
766 pmd_t *pmd, int flags)
767{
768 unsigned long pfn = pmd_pfn(*pmd);
769 struct mm_struct *mm = vma->vm_mm;
770 struct dev_pagemap *pgmap;
771 struct page *page;
772
773 assert_spin_locked(pmd_lockptr(mm, pmd));
774
775 if (flags & FOLL_WRITE && !pmd_write(*pmd))
776 return NULL;
777
778 if (pmd_present(*pmd) && pmd_devmap(*pmd))
779 ;
780 else
781 return NULL;
782
783 if (flags & FOLL_TOUCH)
784 touch_pmd(vma, addr, pmd);
785
786
787
788
789
790 if (!(flags & FOLL_GET))
791 return ERR_PTR(-EEXIST);
792
793 pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT;
794 pgmap = get_dev_pagemap(pfn, NULL);
795 if (!pgmap)
796 return ERR_PTR(-EFAULT);
797 page = pfn_to_page(pfn);
798 get_page(page);
799 put_dev_pagemap(pgmap);
800
801 return page;
802}
803
804int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
805 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
806 struct vm_area_struct *vma)
807{
808 spinlock_t *dst_ptl, *src_ptl;
809 struct page *src_page;
810 pmd_t pmd;
811 pgtable_t pgtable = NULL;
812 int ret = -ENOMEM;
813
814
815 if (!vma_is_anonymous(vma))
816 return 0;
817
818 pgtable = pte_alloc_one(dst_mm, addr);
819 if (unlikely(!pgtable))
820 goto out;
821
822 dst_ptl = pmd_lock(dst_mm, dst_pmd);
823 src_ptl = pmd_lockptr(src_mm, src_pmd);
824 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
825
826 ret = -EAGAIN;
827 pmd = *src_pmd;
828 if (unlikely(!pmd_trans_huge(pmd))) {
829 pte_free(dst_mm, pgtable);
830 goto out_unlock;
831 }
832
833
834
835
836
837 if (is_huge_zero_pmd(pmd)) {
838 struct page *zero_page;
839
840
841
842
843
844 zero_page = mm_get_huge_zero_page(dst_mm);
845 set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd,
846 zero_page);
847 ret = 0;
848 goto out_unlock;
849 }
850
851 src_page = pmd_page(pmd);
852 VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
853 get_page(src_page);
854 page_dup_rmap(src_page, true);
855 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
856 atomic_long_inc(&dst_mm->nr_ptes);
857 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
858
859 pmdp_set_wrprotect(src_mm, addr, src_pmd);
860 pmd = pmd_mkold(pmd_wrprotect(pmd));
861 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
862
863 ret = 0;
864out_unlock:
865 spin_unlock(src_ptl);
866 spin_unlock(dst_ptl);
867out:
868 return ret;
869}
870
871void huge_pmd_set_accessed(struct fault_env *fe, pmd_t orig_pmd)
872{
873 pmd_t entry;
874 unsigned long haddr;
875
876 fe->ptl = pmd_lock(fe->vma->vm_mm, fe->pmd);
877 if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
878 goto unlock;
879
880 entry = pmd_mkyoung(orig_pmd);
881 haddr = fe->address & HPAGE_PMD_MASK;
882 if (pmdp_set_access_flags(fe->vma, haddr, fe->pmd, entry,
883 fe->flags & FAULT_FLAG_WRITE))
884 update_mmu_cache_pmd(fe->vma, fe->address, fe->pmd);
885
886unlock:
887 spin_unlock(fe->ptl);
888}
889
890static int do_huge_pmd_wp_page_fallback(struct fault_env *fe, pmd_t orig_pmd,
891 struct page *page)
892{
893 struct vm_area_struct *vma = fe->vma;
894 unsigned long haddr = fe->address & HPAGE_PMD_MASK;
895 struct mem_cgroup *memcg;
896 pgtable_t pgtable;
897 pmd_t _pmd;
898 int ret = 0, i;
899 struct page **pages;
900 unsigned long mmun_start;
901 unsigned long mmun_end;
902
903 pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR,
904 GFP_KERNEL);
905 if (unlikely(!pages)) {
906 ret |= VM_FAULT_OOM;
907 goto out;
908 }
909
910 for (i = 0; i < HPAGE_PMD_NR; i++) {
911 pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE |
912 __GFP_OTHER_NODE, vma,
913 fe->address, page_to_nid(page));
914 if (unlikely(!pages[i] ||
915 mem_cgroup_try_charge(pages[i], vma->vm_mm,
916 GFP_KERNEL, &memcg, false))) {
917 if (pages[i])
918 put_page(pages[i]);
919 while (--i >= 0) {
920 memcg = (void *)page_private(pages[i]);
921 set_page_private(pages[i], 0);
922 mem_cgroup_cancel_charge(pages[i], memcg,
923 false);
924 put_page(pages[i]);
925 }
926 kfree(pages);
927 ret |= VM_FAULT_OOM;
928 goto out;
929 }
930 set_page_private(pages[i], (unsigned long)memcg);
931 }
932
933 for (i = 0; i < HPAGE_PMD_NR; i++) {
934 copy_user_highpage(pages[i], page + i,
935 haddr + PAGE_SIZE * i, vma);
936 __SetPageUptodate(pages[i]);
937 cond_resched();
938 }
939
940 mmun_start = haddr;
941 mmun_end = haddr + HPAGE_PMD_SIZE;
942 mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
943
944 fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
945 if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
946 goto out_free_pages;
947 VM_BUG_ON_PAGE(!PageHead(page), page);
948
949 pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd);
950
951
952 pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, fe->pmd);
953 pmd_populate(vma->vm_mm, &_pmd, pgtable);
954
955 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
956 pte_t entry;
957 entry = mk_pte(pages[i], vma->vm_page_prot);
958 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
959 memcg = (void *)page_private(pages[i]);
960 set_page_private(pages[i], 0);
961 page_add_new_anon_rmap(pages[i], fe->vma, haddr, false);
962 mem_cgroup_commit_charge(pages[i], memcg, false, false);
963 lru_cache_add_active_or_unevictable(pages[i], vma);
964 fe->pte = pte_offset_map(&_pmd, haddr);
965 VM_BUG_ON(!pte_none(*fe->pte));
966 set_pte_at(vma->vm_mm, haddr, fe->pte, entry);
967 pte_unmap(fe->pte);
968 }
969 kfree(pages);
970
971 smp_wmb();
972 pmd_populate(vma->vm_mm, fe->pmd, pgtable);
973 page_remove_rmap(page, true);
974 spin_unlock(fe->ptl);
975
976 mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
977
978 ret |= VM_FAULT_WRITE;
979 put_page(page);
980
981out:
982 return ret;
983
984out_free_pages:
985 spin_unlock(fe->ptl);
986 mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
987 for (i = 0; i < HPAGE_PMD_NR; i++) {
988 memcg = (void *)page_private(pages[i]);
989 set_page_private(pages[i], 0);
990 mem_cgroup_cancel_charge(pages[i], memcg, false);
991 put_page(pages[i]);
992 }
993 kfree(pages);
994 goto out;
995}
996
997int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd)
998{
999 struct vm_area_struct *vma = fe->vma;
1000 struct page *page = NULL, *new_page;
1001 struct mem_cgroup *memcg;
1002 unsigned long haddr = fe->address & HPAGE_PMD_MASK;
1003 unsigned long mmun_start;
1004 unsigned long mmun_end;
1005 gfp_t huge_gfp;
1006 int ret = 0;
1007
1008 fe->ptl = pmd_lockptr(vma->vm_mm, fe->pmd);
1009 VM_BUG_ON_VMA(!vma->anon_vma, vma);
1010 if (is_huge_zero_pmd(orig_pmd))
1011 goto alloc;
1012 spin_lock(fe->ptl);
1013 if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
1014 goto out_unlock;
1015
1016 page = pmd_page(orig_pmd);
1017 VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page);
1018
1019
1020
1021
1022 if (page_trans_huge_mapcount(page, NULL) == 1) {
1023 pmd_t entry;
1024 entry = pmd_mkyoung(orig_pmd);
1025 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1026 if (pmdp_set_access_flags(vma, haddr, fe->pmd, entry, 1))
1027 update_mmu_cache_pmd(vma, fe->address, fe->pmd);
1028 ret |= VM_FAULT_WRITE;
1029 goto out_unlock;
1030 }
1031 get_page(page);
1032 spin_unlock(fe->ptl);
1033alloc:
1034 if (transparent_hugepage_enabled(vma) &&
1035 !transparent_hugepage_debug_cow()) {
1036 huge_gfp = alloc_hugepage_direct_gfpmask(vma);
1037 new_page = alloc_hugepage_vma(huge_gfp, vma, haddr, HPAGE_PMD_ORDER);
1038 } else
1039 new_page = NULL;
1040
1041 if (likely(new_page)) {
1042 prep_transhuge_page(new_page);
1043 } else {
1044 if (!page) {
1045 split_huge_pmd(vma, fe->pmd, fe->address);
1046 ret |= VM_FAULT_FALLBACK;
1047 } else {
1048 ret = do_huge_pmd_wp_page_fallback(fe, orig_pmd, page);
1049 if (ret & VM_FAULT_OOM) {
1050 split_huge_pmd(vma, fe->pmd, fe->address);
1051 ret |= VM_FAULT_FALLBACK;
1052 }
1053 put_page(page);
1054 }
1055 count_vm_event(THP_FAULT_FALLBACK);
1056 goto out;
1057 }
1058
1059 if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm,
1060 huge_gfp, &memcg, true))) {
1061 put_page(new_page);
1062 split_huge_pmd(vma, fe->pmd, fe->address);
1063 if (page)
1064 put_page(page);
1065 ret |= VM_FAULT_FALLBACK;
1066 count_vm_event(THP_FAULT_FALLBACK);
1067 goto out;
1068 }
1069
1070 count_vm_event(THP_FAULT_ALLOC);
1071
1072 if (!page)
1073 clear_huge_page(new_page, haddr, HPAGE_PMD_NR);
1074 else
1075 copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
1076 __SetPageUptodate(new_page);
1077
1078 mmun_start = haddr;
1079 mmun_end = haddr + HPAGE_PMD_SIZE;
1080 mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
1081
1082 spin_lock(fe->ptl);
1083 if (page)
1084 put_page(page);
1085 if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) {
1086 spin_unlock(fe->ptl);
1087 mem_cgroup_cancel_charge(new_page, memcg, true);
1088 put_page(new_page);
1089 goto out_mn;
1090 } else {
1091 pmd_t entry;
1092 entry = mk_huge_pmd(new_page, vma->vm_page_prot);
1093 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1094 pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd);
1095 page_add_new_anon_rmap(new_page, vma, haddr, true);
1096 mem_cgroup_commit_charge(new_page, memcg, false, true);
1097 lru_cache_add_active_or_unevictable(new_page, vma);
1098 set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
1099 update_mmu_cache_pmd(vma, fe->address, fe->pmd);
1100 if (!page) {
1101 add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
1102 } else {
1103 VM_BUG_ON_PAGE(!PageHead(page), page);
1104 page_remove_rmap(page, true);
1105 put_page(page);
1106 }
1107 ret |= VM_FAULT_WRITE;
1108 }
1109 spin_unlock(fe->ptl);
1110out_mn:
1111 mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
1112out:
1113 return ret;
1114out_unlock:
1115 spin_unlock(fe->ptl);
1116 return ret;
1117}
1118
1119struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
1120 unsigned long addr,
1121 pmd_t *pmd,
1122 unsigned int flags)
1123{
1124 struct mm_struct *mm = vma->vm_mm;
1125 struct page *page = NULL;
1126
1127 assert_spin_locked(pmd_lockptr(mm, pmd));
1128
1129 if (flags & FOLL_WRITE && !pmd_write(*pmd))
1130 goto out;
1131
1132
1133 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1134 return ERR_PTR(-EFAULT);
1135
1136
1137 if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
1138 goto out;
1139
1140 page = pmd_page(*pmd);
1141 VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page);
1142 if (flags & FOLL_TOUCH)
1143 touch_pmd(vma, addr, pmd);
1144 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166 if (PageAnon(page) && compound_mapcount(page) != 1)
1167 goto skip_mlock;
1168 if (PageDoubleMap(page) || !page->mapping)
1169 goto skip_mlock;
1170 if (!trylock_page(page))
1171 goto skip_mlock;
1172 lru_add_drain();
1173 if (page->mapping && !PageDoubleMap(page))
1174 mlock_vma_page(page);
1175 unlock_page(page);
1176 }
1177skip_mlock:
1178 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1179 VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page);
1180 if (flags & FOLL_GET)
1181 get_page(page);
1182
1183out:
1184 return page;
1185}
1186
1187
1188int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t pmd)
1189{
1190 struct vm_area_struct *vma = fe->vma;
1191 struct anon_vma *anon_vma = NULL;
1192 struct page *page;
1193 unsigned long haddr = fe->address & HPAGE_PMD_MASK;
1194 int page_nid = -1, this_nid = numa_node_id();
1195 int target_nid, last_cpupid = -1;
1196 bool page_locked;
1197 bool migrated = false;
1198 bool was_writable;
1199 int flags = 0;
1200
1201 fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
1202 if (unlikely(!pmd_same(pmd, *fe->pmd)))
1203 goto out_unlock;
1204
1205
1206
1207
1208
1209
1210 if (unlikely(pmd_trans_migrating(*fe->pmd))) {
1211 page = pmd_page(*fe->pmd);
1212 spin_unlock(fe->ptl);
1213 wait_on_page_locked(page);
1214 goto out;
1215 }
1216
1217 page = pmd_page(pmd);
1218 BUG_ON(is_huge_zero_page(page));
1219 page_nid = page_to_nid(page);
1220 last_cpupid = page_cpupid_last(page);
1221 count_vm_numa_event(NUMA_HINT_FAULTS);
1222 if (page_nid == this_nid) {
1223 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
1224 flags |= TNF_FAULT_LOCAL;
1225 }
1226
1227
1228 if (!pmd_write(pmd))
1229 flags |= TNF_NO_GROUP;
1230
1231
1232
1233
1234
1235 page_locked = trylock_page(page);
1236 target_nid = mpol_misplaced(page, vma, haddr);
1237 if (target_nid == -1) {
1238
1239 if (page_locked)
1240 goto clear_pmdnuma;
1241 }
1242
1243
1244 if (!page_locked) {
1245 spin_unlock(fe->ptl);
1246 wait_on_page_locked(page);
1247 page_nid = -1;
1248 goto out;
1249 }
1250
1251
1252
1253
1254
1255 get_page(page);
1256 spin_unlock(fe->ptl);
1257 anon_vma = page_lock_anon_vma_read(page);
1258
1259
1260 spin_lock(fe->ptl);
1261 if (unlikely(!pmd_same(pmd, *fe->pmd))) {
1262 unlock_page(page);
1263 put_page(page);
1264 page_nid = -1;
1265 goto out_unlock;
1266 }
1267
1268
1269 if (unlikely(!anon_vma)) {
1270 put_page(page);
1271 page_nid = -1;
1272 goto clear_pmdnuma;
1273 }
1274
1275
1276
1277
1278
1279 spin_unlock(fe->ptl);
1280 migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma,
1281 fe->pmd, pmd, fe->address, page, target_nid);
1282 if (migrated) {
1283 flags |= TNF_MIGRATED;
1284 page_nid = target_nid;
1285 } else
1286 flags |= TNF_MIGRATE_FAIL;
1287
1288 goto out;
1289clear_pmdnuma:
1290 BUG_ON(!PageLocked(page));
1291 was_writable = pmd_write(pmd);
1292 pmd = pmd_modify(pmd, vma->vm_page_prot);
1293 pmd = pmd_mkyoung(pmd);
1294 if (was_writable)
1295 pmd = pmd_mkwrite(pmd);
1296 set_pmd_at(vma->vm_mm, haddr, fe->pmd, pmd);
1297 update_mmu_cache_pmd(vma, fe->address, fe->pmd);
1298 unlock_page(page);
1299out_unlock:
1300 spin_unlock(fe->ptl);
1301
1302out:
1303 if (anon_vma)
1304 page_unlock_anon_vma_read(anon_vma);
1305
1306 if (page_nid != -1)
1307 task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, fe->flags);
1308
1309 return 0;
1310}
1311
1312
1313
1314
1315
1316bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1317 pmd_t *pmd, unsigned long addr, unsigned long next)
1318{
1319 spinlock_t *ptl;
1320 pmd_t orig_pmd;
1321 struct page *page;
1322 struct mm_struct *mm = tlb->mm;
1323 bool ret = false;
1324
1325 ptl = pmd_trans_huge_lock(pmd, vma);
1326 if (!ptl)
1327 goto out_unlocked;
1328
1329 orig_pmd = *pmd;
1330 if (is_huge_zero_pmd(orig_pmd))
1331 goto out;
1332
1333 page = pmd_page(orig_pmd);
1334
1335
1336
1337
1338 if (page_mapcount(page) != 1)
1339 goto out;
1340
1341 if (!trylock_page(page))
1342 goto out;
1343
1344
1345
1346
1347
1348 if (next - addr != HPAGE_PMD_SIZE) {
1349 get_page(page);
1350 spin_unlock(ptl);
1351 split_huge_page(page);
1352 put_page(page);
1353 unlock_page(page);
1354 goto out_unlocked;
1355 }
1356
1357 if (PageDirty(page))
1358 ClearPageDirty(page);
1359 unlock_page(page);
1360
1361 if (PageActive(page))
1362 deactivate_page(page);
1363
1364 if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
1365 orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
1366 tlb->fullmm);
1367 orig_pmd = pmd_mkold(orig_pmd);
1368 orig_pmd = pmd_mkclean(orig_pmd);
1369
1370 set_pmd_at(mm, addr, pmd, orig_pmd);
1371 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1372 }
1373 ret = true;
1374out:
1375 spin_unlock(ptl);
1376out_unlocked:
1377 return ret;
1378}
1379
1380int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1381 pmd_t *pmd, unsigned long addr)
1382{
1383 pmd_t orig_pmd;
1384 spinlock_t *ptl;
1385
1386 ptl = __pmd_trans_huge_lock(pmd, vma);
1387 if (!ptl)
1388 return 0;
1389
1390
1391
1392
1393
1394
1395 orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
1396 tlb->fullmm);
1397 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1398 if (vma_is_dax(vma)) {
1399 spin_unlock(ptl);
1400 if (is_huge_zero_pmd(orig_pmd))
1401 tlb_remove_page(tlb, pmd_page(orig_pmd));
1402 } else if (is_huge_zero_pmd(orig_pmd)) {
1403 pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
1404 atomic_long_dec(&tlb->mm->nr_ptes);
1405 spin_unlock(ptl);
1406 tlb_remove_page(tlb, pmd_page(orig_pmd));
1407 } else {
1408 struct page *page = pmd_page(orig_pmd);
1409 page_remove_rmap(page, true);
1410 VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
1411 VM_BUG_ON_PAGE(!PageHead(page), page);
1412 if (PageAnon(page)) {
1413 pgtable_t pgtable;
1414 pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
1415 pte_free(tlb->mm, pgtable);
1416 atomic_long_dec(&tlb->mm->nr_ptes);
1417 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1418 } else {
1419 add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR);
1420 }
1421 spin_unlock(ptl);
1422 tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE);
1423 }
1424 return 1;
1425}
1426
1427bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
1428 unsigned long new_addr, unsigned long old_end,
1429 pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush)
1430{
1431 spinlock_t *old_ptl, *new_ptl;
1432 pmd_t pmd;
1433 struct mm_struct *mm = vma->vm_mm;
1434 bool force_flush = false;
1435
1436 if ((old_addr & ~HPAGE_PMD_MASK) ||
1437 (new_addr & ~HPAGE_PMD_MASK) ||
1438 old_end - old_addr < HPAGE_PMD_SIZE)
1439 return false;
1440
1441
1442
1443
1444
1445 if (WARN_ON(!pmd_none(*new_pmd))) {
1446 VM_BUG_ON(pmd_trans_huge(*new_pmd));
1447 return false;
1448 }
1449
1450
1451
1452
1453
1454 old_ptl = __pmd_trans_huge_lock(old_pmd, vma);
1455 if (old_ptl) {
1456 new_ptl = pmd_lockptr(mm, new_pmd);
1457 if (new_ptl != old_ptl)
1458 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
1459 pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd);
1460 if (pmd_present(pmd) && pmd_dirty(pmd))
1461 force_flush = true;
1462 VM_BUG_ON(!pmd_none(*new_pmd));
1463
1464 if (pmd_move_must_withdraw(new_ptl, old_ptl) &&
1465 vma_is_anonymous(vma)) {
1466 pgtable_t pgtable;
1467 pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
1468 pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
1469 }
1470 set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
1471 if (new_ptl != old_ptl)
1472 spin_unlock(new_ptl);
1473 if (force_flush)
1474 flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE);
1475 else
1476 *need_flush = true;
1477 spin_unlock(old_ptl);
1478 return true;
1479 }
1480 return false;
1481}
1482
1483
1484
1485
1486
1487
1488
1489int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1490 unsigned long addr, pgprot_t newprot, int prot_numa)
1491{
1492 struct mm_struct *mm = vma->vm_mm;
1493 spinlock_t *ptl;
1494 int ret = 0;
1495
1496 ptl = __pmd_trans_huge_lock(pmd, vma);
1497 if (ptl) {
1498 pmd_t entry;
1499 bool preserve_write = prot_numa && pmd_write(*pmd);
1500 ret = 1;
1501
1502
1503
1504
1505
1506
1507 if (prot_numa && is_huge_zero_pmd(*pmd)) {
1508 spin_unlock(ptl);
1509 return ret;
1510 }
1511
1512 if (!prot_numa || !pmd_protnone(*pmd)) {
1513 entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd);
1514 entry = pmd_modify(entry, newprot);
1515 if (preserve_write)
1516 entry = pmd_mkwrite(entry);
1517 ret = HPAGE_PMD_NR;
1518 set_pmd_at(mm, addr, pmd, entry);
1519 BUG_ON(vma_is_anonymous(vma) && !preserve_write &&
1520 pmd_write(entry));
1521 }
1522 spin_unlock(ptl);
1523 }
1524
1525 return ret;
1526}
1527
1528
1529
1530
1531
1532
1533
1534spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
1535{
1536 spinlock_t *ptl;
1537 ptl = pmd_lock(vma->vm_mm, pmd);
1538 if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
1539 return ptl;
1540 spin_unlock(ptl);
1541 return NULL;
1542}
1543
1544static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
1545 unsigned long haddr, pmd_t *pmd)
1546{
1547 struct mm_struct *mm = vma->vm_mm;
1548 pgtable_t pgtable;
1549 pmd_t _pmd;
1550 int i;
1551
1552
1553 pmdp_huge_clear_flush_notify(vma, haddr, pmd);
1554
1555 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1556 pmd_populate(mm, &_pmd, pgtable);
1557
1558 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1559 pte_t *pte, entry;
1560 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
1561 entry = pte_mkspecial(entry);
1562 pte = pte_offset_map(&_pmd, haddr);
1563 VM_BUG_ON(!pte_none(*pte));
1564 set_pte_at(mm, haddr, pte, entry);
1565 pte_unmap(pte);
1566 }
1567 smp_wmb();
1568 pmd_populate(mm, pmd, pgtable);
1569}
1570
1571static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
1572 unsigned long haddr, bool freeze)
1573{
1574 struct mm_struct *mm = vma->vm_mm;
1575 struct page *page;
1576 pgtable_t pgtable;
1577 pmd_t _pmd;
1578 bool young, write, dirty, soft_dirty;
1579 unsigned long addr;
1580 int i;
1581
1582 VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
1583 VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
1584 VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
1585 VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd));
1586
1587 count_vm_event(THP_SPLIT_PMD);
1588
1589 if (!vma_is_anonymous(vma)) {
1590 _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
1591 if (vma_is_dax(vma))
1592 return;
1593 page = pmd_page(_pmd);
1594 if (!PageReferenced(page) && pmd_young(_pmd))
1595 SetPageReferenced(page);
1596 page_remove_rmap(page, true);
1597 put_page(page);
1598 add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR);
1599 return;
1600 } else if (is_huge_zero_pmd(*pmd)) {
1601 return __split_huge_zero_page_pmd(vma, haddr, pmd);
1602 }
1603
1604 page = pmd_page(*pmd);
1605 VM_BUG_ON_PAGE(!page_count(page), page);
1606 page_ref_add(page, HPAGE_PMD_NR - 1);
1607 write = pmd_write(*pmd);
1608 young = pmd_young(*pmd);
1609 dirty = pmd_dirty(*pmd);
1610 soft_dirty = pmd_soft_dirty(*pmd);
1611
1612 pmdp_huge_split_prepare(vma, haddr, pmd);
1613 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1614 pmd_populate(mm, &_pmd, pgtable);
1615
1616 for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
1617 pte_t entry, *pte;
1618
1619
1620
1621
1622
1623 if (freeze) {
1624 swp_entry_t swp_entry;
1625 swp_entry = make_migration_entry(page + i, write);
1626 entry = swp_entry_to_pte(swp_entry);
1627 if (soft_dirty)
1628 entry = pte_swp_mksoft_dirty(entry);
1629 } else {
1630 entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot));
1631 entry = maybe_mkwrite(entry, vma);
1632 if (!write)
1633 entry = pte_wrprotect(entry);
1634 if (!young)
1635 entry = pte_mkold(entry);
1636 if (soft_dirty)
1637 entry = pte_mksoft_dirty(entry);
1638 }
1639 if (dirty)
1640 SetPageDirty(page + i);
1641 pte = pte_offset_map(&_pmd, addr);
1642 BUG_ON(!pte_none(*pte));
1643 set_pte_at(mm, addr, pte, entry);
1644 atomic_inc(&page[i]._mapcount);
1645 pte_unmap(pte);
1646 }
1647
1648
1649
1650
1651
1652 if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) {
1653 for (i = 0; i < HPAGE_PMD_NR; i++)
1654 atomic_inc(&page[i]._mapcount);
1655 }
1656
1657 if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
1658
1659 __dec_node_page_state(page, NR_ANON_THPS);
1660 if (TestClearPageDoubleMap(page)) {
1661
1662 for (i = 0; i < HPAGE_PMD_NR; i++)
1663 atomic_dec(&page[i]._mapcount);
1664 }
1665 }
1666
1667 smp_wmb();
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689 pmdp_invalidate(vma, haddr, pmd);
1690 pmd_populate(mm, pmd, pgtable);
1691
1692 if (freeze) {
1693 for (i = 0; i < HPAGE_PMD_NR; i++) {
1694 page_remove_rmap(page + i, false);
1695 put_page(page + i);
1696 }
1697 }
1698}
1699
1700void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1701 unsigned long address, bool freeze, struct page *page)
1702{
1703 spinlock_t *ptl;
1704 struct mm_struct *mm = vma->vm_mm;
1705 unsigned long haddr = address & HPAGE_PMD_MASK;
1706
1707 mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
1708 ptl = pmd_lock(mm, pmd);
1709
1710
1711
1712
1713
1714 VM_BUG_ON(freeze && !page);
1715 if (page && page != pmd_page(*pmd))
1716 goto out;
1717
1718 if (pmd_trans_huge(*pmd)) {
1719 page = pmd_page(*pmd);
1720 if (PageMlocked(page))
1721 clear_page_mlock(page);
1722 } else if (!pmd_devmap(*pmd))
1723 goto out;
1724 __split_huge_pmd_locked(vma, pmd, haddr, freeze);
1725out:
1726 spin_unlock(ptl);
1727 mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
1728}
1729
1730void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
1731 bool freeze, struct page *page)
1732{
1733 pgd_t *pgd;
1734 pud_t *pud;
1735 pmd_t *pmd;
1736
1737 pgd = pgd_offset(vma->vm_mm, address);
1738 if (!pgd_present(*pgd))
1739 return;
1740
1741 pud = pud_offset(pgd, address);
1742 if (!pud_present(*pud))
1743 return;
1744
1745 pmd = pmd_offset(pud, address);
1746
1747 __split_huge_pmd(vma, pmd, address, freeze, page);
1748}
1749
1750void vma_adjust_trans_huge(struct vm_area_struct *vma,
1751 unsigned long start,
1752 unsigned long end,
1753 long adjust_next)
1754{
1755
1756
1757
1758
1759
1760 if (start & ~HPAGE_PMD_MASK &&
1761 (start & HPAGE_PMD_MASK) >= vma->vm_start &&
1762 (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
1763 split_huge_pmd_address(vma, start, false, NULL);
1764
1765
1766
1767
1768
1769
1770 if (end & ~HPAGE_PMD_MASK &&
1771 (end & HPAGE_PMD_MASK) >= vma->vm_start &&
1772 (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
1773 split_huge_pmd_address(vma, end, false, NULL);
1774
1775
1776
1777
1778
1779
1780 if (adjust_next > 0) {
1781 struct vm_area_struct *next = vma->vm_next;
1782 unsigned long nstart = next->vm_start;
1783 nstart += adjust_next << PAGE_SHIFT;
1784 if (nstart & ~HPAGE_PMD_MASK &&
1785 (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
1786 (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
1787 split_huge_pmd_address(next, nstart, false, NULL);
1788 }
1789}
1790
1791static void freeze_page(struct page *page)
1792{
1793 enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
1794 TTU_RMAP_LOCKED;
1795 int i, ret;
1796
1797 VM_BUG_ON_PAGE(!PageHead(page), page);
1798
1799 if (PageAnon(page))
1800 ttu_flags |= TTU_MIGRATION;
1801
1802
1803 ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
1804 for (i = 1; !ret && i < HPAGE_PMD_NR; i++) {
1805
1806 if (page_count(page) == 1)
1807 return;
1808
1809 ret = try_to_unmap(page + i, ttu_flags);
1810 }
1811 VM_BUG_ON_PAGE(ret, page + i - 1);
1812}
1813
1814static void unfreeze_page(struct page *page)
1815{
1816 int i;
1817
1818 for (i = 0; i < HPAGE_PMD_NR; i++)
1819 remove_migration_ptes(page + i, page + i, true);
1820}
1821
1822static void __split_huge_page_tail(struct page *head, int tail,
1823 struct lruvec *lruvec, struct list_head *list)
1824{
1825 struct page *page_tail = head + tail;
1826
1827 VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail);
1828 VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail);
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841 if (PageAnon(head)) {
1842 page_ref_inc(page_tail);
1843 } else {
1844
1845 page_ref_add(page_tail, 2);
1846 }
1847
1848 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1849 page_tail->flags |= (head->flags &
1850 ((1L << PG_referenced) |
1851 (1L << PG_swapbacked) |
1852 (1L << PG_mlocked) |
1853 (1L << PG_uptodate) |
1854 (1L << PG_active) |
1855 (1L << PG_locked) |
1856 (1L << PG_unevictable) |
1857 (1L << PG_dirty)));
1858
1859
1860
1861
1862
1863 smp_wmb();
1864
1865 clear_compound_head(page_tail);
1866
1867 if (page_is_young(head))
1868 set_page_young(page_tail);
1869 if (page_is_idle(head))
1870 set_page_idle(page_tail);
1871
1872
1873 VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
1874 page_tail);
1875 page_tail->mapping = head->mapping;
1876
1877 page_tail->index = head->index + tail;
1878 page_cpupid_xchg_last(page_tail, page_cpupid_last(head));
1879 lru_add_page_tail(head, page_tail, lruvec, list);
1880}
1881
1882static void __split_huge_page(struct page *page, struct list_head *list,
1883 unsigned long flags)
1884{
1885 struct page *head = compound_head(page);
1886 struct zone *zone = page_zone(head);
1887 struct lruvec *lruvec;
1888 pgoff_t end = -1;
1889 int i;
1890
1891 lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat);
1892
1893
1894 mem_cgroup_split_huge_fixup(head);
1895
1896 if (!PageAnon(page))
1897 end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE);
1898
1899 for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
1900 __split_huge_page_tail(head, i, lruvec, list);
1901
1902 if (head[i].index >= end) {
1903 __ClearPageDirty(head + i);
1904 __delete_from_page_cache(head + i, NULL);
1905 if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
1906 shmem_uncharge(head->mapping->host, 1);
1907 put_page(head + i);
1908 }
1909 }
1910
1911 ClearPageCompound(head);
1912
1913 if (PageAnon(head)) {
1914 page_ref_inc(head);
1915 } else {
1916
1917 page_ref_add(head, 2);
1918 spin_unlock(&head->mapping->tree_lock);
1919 }
1920
1921 spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
1922
1923 unfreeze_page(head);
1924
1925 for (i = 0; i < HPAGE_PMD_NR; i++) {
1926 struct page *subpage = head + i;
1927 if (subpage == page)
1928 continue;
1929 unlock_page(subpage);
1930
1931
1932
1933
1934
1935
1936
1937
1938 put_page(subpage);
1939 }
1940}
1941
1942int total_mapcount(struct page *page)
1943{
1944 int i, compound, ret;
1945
1946 VM_BUG_ON_PAGE(PageTail(page), page);
1947
1948 if (likely(!PageCompound(page)))
1949 return atomic_read(&page->_mapcount) + 1;
1950
1951 compound = compound_mapcount(page);
1952 if (PageHuge(page))
1953 return compound;
1954 ret = compound;
1955 for (i = 0; i < HPAGE_PMD_NR; i++)
1956 ret += atomic_read(&page[i]._mapcount) + 1;
1957
1958 if (!PageAnon(page))
1959 return ret - compound * HPAGE_PMD_NR;
1960 if (PageDoubleMap(page))
1961 ret -= HPAGE_PMD_NR;
1962 return ret;
1963}
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989int page_trans_huge_mapcount(struct page *page, int *total_mapcount)
1990{
1991 int i, ret, _total_mapcount, mapcount;
1992
1993
1994 VM_BUG_ON_PAGE(PageHuge(page), page);
1995
1996 if (likely(!PageTransCompound(page))) {
1997 mapcount = atomic_read(&page->_mapcount) + 1;
1998 if (total_mapcount)
1999 *total_mapcount = mapcount;
2000 return mapcount;
2001 }
2002
2003 page = compound_head(page);
2004
2005 _total_mapcount = ret = 0;
2006 for (i = 0; i < HPAGE_PMD_NR; i++) {
2007 mapcount = atomic_read(&page[i]._mapcount) + 1;
2008 ret = max(ret, mapcount);
2009 _total_mapcount += mapcount;
2010 }
2011 if (PageDoubleMap(page)) {
2012 ret -= 1;
2013 _total_mapcount -= HPAGE_PMD_NR;
2014 }
2015 mapcount = compound_mapcount(page);
2016 ret += mapcount;
2017 _total_mapcount += mapcount;
2018 if (total_mapcount)
2019 *total_mapcount = _total_mapcount;
2020 return ret;
2021}
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042int split_huge_page_to_list(struct page *page, struct list_head *list)
2043{
2044 struct page *head = compound_head(page);
2045 struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
2046 struct anon_vma *anon_vma = NULL;
2047 struct address_space *mapping = NULL;
2048 int count, mapcount, extra_pins, ret;
2049 bool mlocked;
2050 unsigned long flags;
2051
2052 VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
2053 VM_BUG_ON_PAGE(!PageLocked(page), page);
2054 VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
2055 VM_BUG_ON_PAGE(!PageCompound(page), page);
2056
2057 if (PageAnon(head)) {
2058
2059
2060
2061
2062
2063
2064
2065
2066 anon_vma = page_get_anon_vma(head);
2067 if (!anon_vma) {
2068 ret = -EBUSY;
2069 goto out;
2070 }
2071 extra_pins = 0;
2072 mapping = NULL;
2073 anon_vma_lock_write(anon_vma);
2074 } else {
2075 mapping = head->mapping;
2076
2077
2078 if (!mapping) {
2079 ret = -EBUSY;
2080 goto out;
2081 }
2082
2083
2084 extra_pins = HPAGE_PMD_NR;
2085 anon_vma = NULL;
2086 i_mmap_lock_read(mapping);
2087 }
2088
2089
2090
2091
2092
2093 if (total_mapcount(head) != page_count(head) - extra_pins - 1) {
2094 ret = -EBUSY;
2095 goto out_unlock;
2096 }
2097
2098 mlocked = PageMlocked(page);
2099 freeze_page(head);
2100 VM_BUG_ON_PAGE(compound_mapcount(head), head);
2101
2102
2103 if (mlocked)
2104 lru_add_drain();
2105
2106
2107 spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags);
2108
2109 if (mapping) {
2110 void **pslot;
2111
2112 spin_lock(&mapping->tree_lock);
2113 pslot = radix_tree_lookup_slot(&mapping->page_tree,
2114 page_index(head));
2115
2116
2117
2118
2119 if (radix_tree_deref_slot_protected(pslot,
2120 &mapping->tree_lock) != head)
2121 goto fail;
2122 }
2123
2124
2125 spin_lock(&pgdata->split_queue_lock);
2126 count = page_count(head);
2127 mapcount = total_mapcount(head);
2128 if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) {
2129 if (!list_empty(page_deferred_list(head))) {
2130 pgdata->split_queue_len--;
2131 list_del(page_deferred_list(head));
2132 }
2133 if (mapping)
2134 __dec_node_page_state(page, NR_SHMEM_THPS);
2135 spin_unlock(&pgdata->split_queue_lock);
2136 __split_huge_page(page, list, flags);
2137 ret = 0;
2138 } else {
2139 if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
2140 pr_alert("total_mapcount: %u, page_count(): %u\n",
2141 mapcount, count);
2142 if (PageTail(page))
2143 dump_page(head, NULL);
2144 dump_page(page, "total_mapcount(head) > 0");
2145 BUG();
2146 }
2147 spin_unlock(&pgdata->split_queue_lock);
2148fail: if (mapping)
2149 spin_unlock(&mapping->tree_lock);
2150 spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
2151 unfreeze_page(head);
2152 ret = -EBUSY;
2153 }
2154
2155out_unlock:
2156 if (anon_vma) {
2157 anon_vma_unlock_write(anon_vma);
2158 put_anon_vma(anon_vma);
2159 }
2160 if (mapping)
2161 i_mmap_unlock_read(mapping);
2162out:
2163 count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
2164 return ret;
2165}
2166
2167void free_transhuge_page(struct page *page)
2168{
2169 struct pglist_data *pgdata = NODE_DATA(page_to_nid(page));
2170 unsigned long flags;
2171
2172 spin_lock_irqsave(&pgdata->split_queue_lock, flags);
2173 if (!list_empty(page_deferred_list(page))) {
2174 pgdata->split_queue_len--;
2175 list_del(page_deferred_list(page));
2176 }
2177 spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
2178 free_compound_page(page);
2179}
2180
2181void deferred_split_huge_page(struct page *page)
2182{
2183 struct pglist_data *pgdata = NODE_DATA(page_to_nid(page));
2184 unsigned long flags;
2185
2186 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
2187
2188 spin_lock_irqsave(&pgdata->split_queue_lock, flags);
2189 if (list_empty(page_deferred_list(page))) {
2190 count_vm_event(THP_DEFERRED_SPLIT_PAGE);
2191 list_add_tail(page_deferred_list(page), &pgdata->split_queue);
2192 pgdata->split_queue_len++;
2193 }
2194 spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
2195}
2196
2197static unsigned long deferred_split_count(struct shrinker *shrink,
2198 struct shrink_control *sc)
2199{
2200 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2201 return ACCESS_ONCE(pgdata->split_queue_len);
2202}
2203
2204static unsigned long deferred_split_scan(struct shrinker *shrink,
2205 struct shrink_control *sc)
2206{
2207 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2208 unsigned long flags;
2209 LIST_HEAD(list), *pos, *next;
2210 struct page *page;
2211 int split = 0;
2212
2213 spin_lock_irqsave(&pgdata->split_queue_lock, flags);
2214
2215 list_for_each_safe(pos, next, &pgdata->split_queue) {
2216 page = list_entry((void *)pos, struct page, mapping);
2217 page = compound_head(page);
2218 if (get_page_unless_zero(page)) {
2219 list_move(page_deferred_list(page), &list);
2220 } else {
2221
2222 list_del_init(page_deferred_list(page));
2223 pgdata->split_queue_len--;
2224 }
2225 if (!--sc->nr_to_scan)
2226 break;
2227 }
2228 spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
2229
2230 list_for_each_safe(pos, next, &list) {
2231 page = list_entry((void *)pos, struct page, mapping);
2232 lock_page(page);
2233
2234 if (!split_huge_page(page))
2235 split++;
2236 unlock_page(page);
2237 put_page(page);
2238 }
2239
2240 spin_lock_irqsave(&pgdata->split_queue_lock, flags);
2241 list_splice_tail(&list, &pgdata->split_queue);
2242 spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
2243
2244
2245
2246
2247
2248 if (!split && list_empty(&pgdata->split_queue))
2249 return SHRINK_STOP;
2250 return split;
2251}
2252
2253static struct shrinker deferred_split_shrinker = {
2254 .count_objects = deferred_split_count,
2255 .scan_objects = deferred_split_scan,
2256 .seeks = DEFAULT_SEEKS,
2257 .flags = SHRINKER_NUMA_AWARE,
2258};
2259
2260#ifdef CONFIG_DEBUG_FS
2261static int split_huge_pages_set(void *data, u64 val)
2262{
2263 struct zone *zone;
2264 struct page *page;
2265 unsigned long pfn, max_zone_pfn;
2266 unsigned long total = 0, split = 0;
2267
2268 if (val != 1)
2269 return -EINVAL;
2270
2271 for_each_populated_zone(zone) {
2272 max_zone_pfn = zone_end_pfn(zone);
2273 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
2274 if (!pfn_valid(pfn))
2275 continue;
2276
2277 page = pfn_to_page(pfn);
2278 if (!get_page_unless_zero(page))
2279 continue;
2280
2281 if (zone != page_zone(page))
2282 goto next;
2283
2284 if (!PageHead(page) || PageHuge(page) || !PageLRU(page))
2285 goto next;
2286
2287 total++;
2288 lock_page(page);
2289 if (!split_huge_page(page))
2290 split++;
2291 unlock_page(page);
2292next:
2293 put_page(page);
2294 }
2295 }
2296
2297 pr_info("%lu of %lu THP split\n", split, total);
2298
2299 return 0;
2300}
2301DEFINE_SIMPLE_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set,
2302 "%llu\n");
2303
2304static int __init split_huge_pages_debugfs(void)
2305{
2306 void *ret;
2307
2308 ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL,
2309 &split_huge_pages_fops);
2310 if (!ret)
2311 pr_warn("Failed to create split_huge_pages in debugfs");
2312 return 0;
2313}
2314late_initcall(split_huge_pages_debugfs);
2315#endif
2316