1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2009 Red Hat, Inc.
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 #include <linux/sched.h>
10 #include <linux/sched/coredump.h>
11 #include <linux/sched/numa_balancing.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 #include <linux/oom.h>
34 #include <linux/numa.h>
35 #include <linux/page_owner.h>
38 #include <asm/pgalloc.h>
42 * By default, transparent hugepage support is disabled in order to avoid
43 * risking an increased memory footprint for applications that are not
44 * guaranteed to benefit from it. When transparent hugepage support is
45 * enabled, it is for all mappings, and khugepaged scans all mappings.
46 * Defrag is invoked by khugepaged hugepage allocations and by page faults
47 * for all hugepage allocations.
49 unsigned long transparent_hugepage_flags __read_mostly =
50 #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
51 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
53 #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
54 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
56 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)|
57 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
58 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
60 static struct shrinker deferred_split_shrinker;
62 static atomic_t huge_zero_refcount;
63 struct page *huge_zero_page __read_mostly;
65 bool transparent_hugepage_enabled(struct vm_area_struct *vma)
67 /* The addr is used to check if the vma size fits */
68 unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE;
70 if (!transhuge_vma_suitable(vma, addr))
72 if (vma_is_anonymous(vma))
73 return __transparent_hugepage_enabled(vma);
74 if (vma_is_shmem(vma))
75 return shmem_huge_enabled(vma);
80 static struct page *get_huge_zero_page(void)
82 struct page *zero_page;
84 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
85 return READ_ONCE(huge_zero_page);
87 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
90 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
93 count_vm_event(THP_ZERO_PAGE_ALLOC);
95 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
97 __free_pages(zero_page, compound_order(zero_page));
101 /* We take additional reference here. It will be put back by shrinker */
102 atomic_set(&huge_zero_refcount, 2);
104 return READ_ONCE(huge_zero_page);
107 static void put_huge_zero_page(void)
110 * Counter should never go to zero here. Only shrinker can put
113 BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
116 struct page *mm_get_huge_zero_page(struct mm_struct *mm)
118 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
119 return READ_ONCE(huge_zero_page);
121 if (!get_huge_zero_page())
124 if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
125 put_huge_zero_page();
127 return READ_ONCE(huge_zero_page);
130 void mm_put_huge_zero_page(struct mm_struct *mm)
132 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
133 put_huge_zero_page();
136 static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink,
137 struct shrink_control *sc)
139 /* we can free zero page only if last reference remains */
140 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
143 static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
144 struct shrink_control *sc)
146 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
147 struct page *zero_page = xchg(&huge_zero_page, NULL);
148 BUG_ON(zero_page == NULL);
149 __free_pages(zero_page, compound_order(zero_page));
156 static struct shrinker huge_zero_page_shrinker = {
157 .count_objects = shrink_huge_zero_page_count,
158 .scan_objects = shrink_huge_zero_page_scan,
159 .seeks = DEFAULT_SEEKS,
163 static ssize_t enabled_show(struct kobject *kobj,
164 struct kobj_attribute *attr, char *buf)
166 if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags))
167 return sprintf(buf, "[always] madvise never\n");
168 else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags))
169 return sprintf(buf, "always [madvise] never\n");
171 return sprintf(buf, "always madvise [never]\n");
174 static ssize_t enabled_store(struct kobject *kobj,
175 struct kobj_attribute *attr,
176 const char *buf, size_t count)
180 if (sysfs_streq(buf, "always")) {
181 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
182 set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
183 } else if (sysfs_streq(buf, "madvise")) {
184 clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
185 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
186 } else if (sysfs_streq(buf, "never")) {
187 clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
188 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
193 int err = start_stop_khugepaged();
199 static struct kobj_attribute enabled_attr =
200 __ATTR(enabled, 0644, enabled_show, enabled_store);
202 ssize_t single_hugepage_flag_show(struct kobject *kobj,
203 struct kobj_attribute *attr, char *buf,
204 enum transparent_hugepage_flag flag)
206 return sprintf(buf, "%d\n",
207 !!test_bit(flag, &transparent_hugepage_flags));
210 ssize_t single_hugepage_flag_store(struct kobject *kobj,
211 struct kobj_attribute *attr,
212 const char *buf, size_t count,
213 enum transparent_hugepage_flag flag)
218 ret = kstrtoul(buf, 10, &value);
225 set_bit(flag, &transparent_hugepage_flags);
227 clear_bit(flag, &transparent_hugepage_flags);
232 static ssize_t defrag_show(struct kobject *kobj,
233 struct kobj_attribute *attr, char *buf)
235 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags))
236 return sprintf(buf, "[always] defer defer+madvise madvise never\n");
237 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags))
238 return sprintf(buf, "always [defer] defer+madvise madvise never\n");
239 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags))
240 return sprintf(buf, "always defer [defer+madvise] madvise never\n");
241 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags))
242 return sprintf(buf, "always defer defer+madvise [madvise] never\n");
243 return sprintf(buf, "always defer defer+madvise madvise [never]\n");
246 static ssize_t defrag_store(struct kobject *kobj,
247 struct kobj_attribute *attr,
248 const char *buf, size_t count)
250 if (sysfs_streq(buf, "always")) {
251 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
252 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
253 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
254 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
255 } else if (sysfs_streq(buf, "defer+madvise")) {
256 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
257 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
258 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
259 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
260 } else if (sysfs_streq(buf, "defer")) {
261 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
262 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
263 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
264 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
265 } else if (sysfs_streq(buf, "madvise")) {
266 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
267 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
268 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
269 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
270 } else if (sysfs_streq(buf, "never")) {
271 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
272 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
273 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
274 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
280 static struct kobj_attribute defrag_attr =
281 __ATTR(defrag, 0644, defrag_show, defrag_store);
283 static ssize_t use_zero_page_show(struct kobject *kobj,
284 struct kobj_attribute *attr, char *buf)
286 return single_hugepage_flag_show(kobj, attr, buf,
287 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
289 static ssize_t use_zero_page_store(struct kobject *kobj,
290 struct kobj_attribute *attr, const char *buf, size_t count)
292 return single_hugepage_flag_store(kobj, attr, buf, count,
293 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
295 static struct kobj_attribute use_zero_page_attr =
296 __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
298 static ssize_t hpage_pmd_size_show(struct kobject *kobj,
299 struct kobj_attribute *attr, char *buf)
301 return sprintf(buf, "%lu\n", HPAGE_PMD_SIZE);
303 static struct kobj_attribute hpage_pmd_size_attr =
304 __ATTR_RO(hpage_pmd_size);
306 #ifdef CONFIG_DEBUG_VM
307 static ssize_t debug_cow_show(struct kobject *kobj,
308 struct kobj_attribute *attr, char *buf)
310 return single_hugepage_flag_show(kobj, attr, buf,
311 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
313 static ssize_t debug_cow_store(struct kobject *kobj,
314 struct kobj_attribute *attr,
315 const char *buf, size_t count)
317 return single_hugepage_flag_store(kobj, attr, buf, count,
318 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
320 static struct kobj_attribute debug_cow_attr =
321 __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store);
322 #endif /* CONFIG_DEBUG_VM */
324 static struct attribute *hugepage_attr[] = {
327 &use_zero_page_attr.attr,
328 &hpage_pmd_size_attr.attr,
330 &shmem_enabled_attr.attr,
332 #ifdef CONFIG_DEBUG_VM
333 &debug_cow_attr.attr,
338 static const struct attribute_group hugepage_attr_group = {
339 .attrs = hugepage_attr,
342 static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
346 *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
347 if (unlikely(!*hugepage_kobj)) {
348 pr_err("failed to create transparent hugepage kobject\n");
352 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
354 pr_err("failed to register transparent hugepage group\n");
358 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
360 pr_err("failed to register transparent hugepage group\n");
361 goto remove_hp_group;
367 sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group);
369 kobject_put(*hugepage_kobj);
373 static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj)
375 sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
376 sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
377 kobject_put(hugepage_kobj);
380 static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj)
385 static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj)
388 #endif /* CONFIG_SYSFS */
390 static int __init hugepage_init(void)
393 struct kobject *hugepage_kobj;
395 if (!has_transparent_hugepage()) {
396 transparent_hugepage_flags = 0;
401 * hugepages can't be allocated by the buddy allocator
403 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
405 * we use page->mapping and page->index in second tail page
406 * as list_head: assuming THP order >= 2
408 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2);
410 err = hugepage_init_sysfs(&hugepage_kobj);
414 err = khugepaged_init();
418 err = register_shrinker(&huge_zero_page_shrinker);
420 goto err_hzp_shrinker;
421 err = register_shrinker(&deferred_split_shrinker);
423 goto err_split_shrinker;
426 * By default disable transparent hugepages on smaller systems,
427 * where the extra memory used could hurt more than TLB overhead
428 * is likely to save. The admin can still enable it through /sys.
430 if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) {
431 transparent_hugepage_flags = 0;
435 err = start_stop_khugepaged();
441 unregister_shrinker(&deferred_split_shrinker);
443 unregister_shrinker(&huge_zero_page_shrinker);
445 khugepaged_destroy();
447 hugepage_exit_sysfs(hugepage_kobj);
451 subsys_initcall(hugepage_init);
453 static int __init setup_transparent_hugepage(char *str)
458 if (!strcmp(str, "always")) {
459 set_bit(TRANSPARENT_HUGEPAGE_FLAG,
460 &transparent_hugepage_flags);
461 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
462 &transparent_hugepage_flags);
464 } else if (!strcmp(str, "madvise")) {
465 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
466 &transparent_hugepage_flags);
467 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
468 &transparent_hugepage_flags);
470 } else if (!strcmp(str, "never")) {
471 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
472 &transparent_hugepage_flags);
473 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
474 &transparent_hugepage_flags);
479 pr_warn("transparent_hugepage= cannot parse, ignored\n");
482 __setup("transparent_hugepage=", setup_transparent_hugepage);
484 pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
486 if (likely(vma->vm_flags & VM_WRITE))
487 pmd = pmd_mkwrite(pmd);
492 static inline struct deferred_split *get_deferred_split_queue(struct page *page)
494 struct mem_cgroup *memcg = compound_head(page)->mem_cgroup;
495 struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
498 return &memcg->deferred_split_queue;
500 return &pgdat->deferred_split_queue;
503 static inline struct deferred_split *get_deferred_split_queue(struct page *page)
505 struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
507 return &pgdat->deferred_split_queue;
511 void prep_transhuge_page(struct page *page)
514 * we use page->mapping and page->indexlru in second tail page
515 * as list_head: assuming THP order >= 2
518 INIT_LIST_HEAD(page_deferred_list(page));
519 set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);
522 bool is_transparent_hugepage(struct page *page)
524 if (!PageCompound(page))
527 page = compound_head(page);
528 return is_huge_zero_page(page) ||
529 page[1].compound_dtor == TRANSHUGE_PAGE_DTOR;
531 EXPORT_SYMBOL_GPL(is_transparent_hugepage);
533 static unsigned long __thp_get_unmapped_area(struct file *filp,
534 unsigned long addr, unsigned long len,
535 loff_t off, unsigned long flags, unsigned long size)
537 loff_t off_end = off + len;
538 loff_t off_align = round_up(off, size);
539 unsigned long len_pad, ret;
541 if (off_end <= off_align || (off_end - off_align) < size)
544 len_pad = len + size;
545 if (len_pad < len || (off + len_pad) < off)
548 ret = current->mm->get_unmapped_area(filp, addr, len_pad,
549 off >> PAGE_SHIFT, flags);
552 * The failure might be due to length padding. The caller will retry
553 * without the padding.
555 if (IS_ERR_VALUE(ret))
559 * Do not try to align to THP boundary if allocation at the address
565 ret += (off - ret) & (size - 1);
569 unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
570 unsigned long len, unsigned long pgoff, unsigned long flags)
573 loff_t off = (loff_t)pgoff << PAGE_SHIFT;
575 if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD))
578 ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE);
582 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
584 EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
586 static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
587 struct page *page, gfp_t gfp)
589 struct vm_area_struct *vma = vmf->vma;
591 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
594 VM_BUG_ON_PAGE(!PageCompound(page), page);
596 if (mem_cgroup_charge(page, vma->vm_mm, gfp)) {
598 count_vm_event(THP_FAULT_FALLBACK);
599 count_vm_event(THP_FAULT_FALLBACK_CHARGE);
600 return VM_FAULT_FALLBACK;
602 cgroup_throttle_swaprate(page, gfp);
604 pgtable = pte_alloc_one(vma->vm_mm);
605 if (unlikely(!pgtable)) {
610 clear_huge_page(page, vmf->address, HPAGE_PMD_NR);
612 * The memory barrier inside __SetPageUptodate makes sure that
613 * clear_huge_page writes become visible before the set_pmd_at()
616 __SetPageUptodate(page);
618 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
619 if (unlikely(!pmd_none(*vmf->pmd))) {
624 ret = check_stable_address_space(vma->vm_mm);
628 /* Deliver the page fault to userland */
629 if (userfaultfd_missing(vma)) {
632 spin_unlock(vmf->ptl);
634 pte_free(vma->vm_mm, pgtable);
635 ret2 = handle_userfault(vmf, VM_UFFD_MISSING);
636 VM_BUG_ON(ret2 & VM_FAULT_FALLBACK);
640 entry = mk_huge_pmd(page, vma->vm_page_prot);
641 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
642 page_add_new_anon_rmap(page, vma, haddr, true);
643 lru_cache_add_inactive_or_unevictable(page, vma);
644 pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
645 set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
646 add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
647 mm_inc_nr_ptes(vma->vm_mm);
648 spin_unlock(vmf->ptl);
649 count_vm_event(THP_FAULT_ALLOC);
650 count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
655 spin_unlock(vmf->ptl);
658 pte_free(vma->vm_mm, pgtable);
665 * always: directly stall for all thp allocations
666 * defer: wake kswapd and fail if not immediately available
667 * defer+madvise: wake kswapd and directly stall for MADV_HUGEPAGE, otherwise
668 * fail if not immediately available
669 * madvise: directly stall for MADV_HUGEPAGE, otherwise fail if not immediately
671 * never: never stall for any thp allocation
673 static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma)
675 const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE);
677 /* Always do synchronous compaction */
678 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags))
679 return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY);
681 /* Kick kcompactd and fail quickly */
682 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags))
683 return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM;
685 /* Synchronous compaction if madvised, otherwise kick kcompactd */
686 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags))
687 return GFP_TRANSHUGE_LIGHT |
688 (vma_madvised ? __GFP_DIRECT_RECLAIM :
689 __GFP_KSWAPD_RECLAIM);
691 /* Only do synchronous compaction if madvised */
692 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags))
693 return GFP_TRANSHUGE_LIGHT |
694 (vma_madvised ? __GFP_DIRECT_RECLAIM : 0);
696 return GFP_TRANSHUGE_LIGHT;
699 /* Caller must hold page table lock. */
700 static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
701 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
702 struct page *zero_page)
707 entry = mk_pmd(zero_page, vma->vm_page_prot);
708 entry = pmd_mkhuge(entry);
710 pgtable_trans_huge_deposit(mm, pmd, pgtable);
711 set_pmd_at(mm, haddr, pmd, entry);
716 vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
718 struct vm_area_struct *vma = vmf->vma;
721 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
723 if (!transhuge_vma_suitable(vma, haddr))
724 return VM_FAULT_FALLBACK;
725 if (unlikely(anon_vma_prepare(vma)))
727 if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
729 if (!(vmf->flags & FAULT_FLAG_WRITE) &&
730 !mm_forbids_zeropage(vma->vm_mm) &&
731 transparent_hugepage_use_zero_page()) {
733 struct page *zero_page;
736 pgtable = pte_alloc_one(vma->vm_mm);
737 if (unlikely(!pgtable))
739 zero_page = mm_get_huge_zero_page(vma->vm_mm);
740 if (unlikely(!zero_page)) {
741 pte_free(vma->vm_mm, pgtable);
742 count_vm_event(THP_FAULT_FALLBACK);
743 return VM_FAULT_FALLBACK;
745 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
748 if (pmd_none(*vmf->pmd)) {
749 ret = check_stable_address_space(vma->vm_mm);
751 spin_unlock(vmf->ptl);
752 } else if (userfaultfd_missing(vma)) {
753 spin_unlock(vmf->ptl);
754 ret = handle_userfault(vmf, VM_UFFD_MISSING);
755 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
757 set_huge_zero_page(pgtable, vma->vm_mm, vma,
758 haddr, vmf->pmd, zero_page);
759 spin_unlock(vmf->ptl);
763 spin_unlock(vmf->ptl);
765 pte_free(vma->vm_mm, pgtable);
768 gfp = alloc_hugepage_direct_gfpmask(vma);
769 page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
770 if (unlikely(!page)) {
771 count_vm_event(THP_FAULT_FALLBACK);
772 return VM_FAULT_FALLBACK;
774 prep_transhuge_page(page);
775 return __do_huge_pmd_anonymous_page(vmf, page, gfp);
778 static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
779 pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write,
782 struct mm_struct *mm = vma->vm_mm;
786 ptl = pmd_lock(mm, pmd);
787 if (!pmd_none(*pmd)) {
789 if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) {
790 WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
793 entry = pmd_mkyoung(*pmd);
794 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
795 if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
796 update_mmu_cache_pmd(vma, addr, pmd);
802 entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
803 if (pfn_t_devmap(pfn))
804 entry = pmd_mkdevmap(entry);
806 entry = pmd_mkyoung(pmd_mkdirty(entry));
807 entry = maybe_pmd_mkwrite(entry, vma);
811 pgtable_trans_huge_deposit(mm, pmd, pgtable);
816 set_pmd_at(mm, addr, pmd, entry);
817 update_mmu_cache_pmd(vma, addr, pmd);
822 pte_free(mm, pgtable);
826 * vmf_insert_pfn_pmd_prot - insert a pmd size pfn
827 * @vmf: Structure describing the fault
828 * @pfn: pfn to insert
829 * @pgprot: page protection to use
830 * @write: whether it's a write fault
832 * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and
833 * also consult the vmf_insert_mixed_prot() documentation when
834 * @pgprot != @vmf->vma->vm_page_prot.
836 * Return: vm_fault_t value.
838 vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn,
839 pgprot_t pgprot, bool write)
841 unsigned long addr = vmf->address & PMD_MASK;
842 struct vm_area_struct *vma = vmf->vma;
843 pgtable_t pgtable = NULL;
846 * If we had pmd_special, we could avoid all these restrictions,
847 * but we need to be consistent with PTEs and architectures that
848 * can't support a 'special' bit.
850 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
852 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
853 (VM_PFNMAP|VM_MIXEDMAP));
854 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
856 if (addr < vma->vm_start || addr >= vma->vm_end)
857 return VM_FAULT_SIGBUS;
859 if (arch_needs_pgtable_deposit()) {
860 pgtable = pte_alloc_one(vma->vm_mm);
865 track_pfn_insert(vma, &pgprot, pfn);
867 insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable);
868 return VM_FAULT_NOPAGE;
870 EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot);
872 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
873 static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma)
875 if (likely(vma->vm_flags & VM_WRITE))
876 pud = pud_mkwrite(pud);
880 static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
881 pud_t *pud, pfn_t pfn, pgprot_t prot, bool write)
883 struct mm_struct *mm = vma->vm_mm;
887 ptl = pud_lock(mm, pud);
888 if (!pud_none(*pud)) {
890 if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
891 WARN_ON_ONCE(!is_huge_zero_pud(*pud));
894 entry = pud_mkyoung(*pud);
895 entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
896 if (pudp_set_access_flags(vma, addr, pud, entry, 1))
897 update_mmu_cache_pud(vma, addr, pud);
902 entry = pud_mkhuge(pfn_t_pud(pfn, prot));
903 if (pfn_t_devmap(pfn))
904 entry = pud_mkdevmap(entry);
906 entry = pud_mkyoung(pud_mkdirty(entry));
907 entry = maybe_pud_mkwrite(entry, vma);
909 set_pud_at(mm, addr, pud, entry);
910 update_mmu_cache_pud(vma, addr, pud);
917 * vmf_insert_pfn_pud_prot - insert a pud size pfn
918 * @vmf: Structure describing the fault
919 * @pfn: pfn to insert
920 * @pgprot: page protection to use
921 * @write: whether it's a write fault
923 * Insert a pud size pfn. See vmf_insert_pfn() for additional info and
924 * also consult the vmf_insert_mixed_prot() documentation when
925 * @pgprot != @vmf->vma->vm_page_prot.
927 * Return: vm_fault_t value.
929 vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn,
930 pgprot_t pgprot, bool write)
932 unsigned long addr = vmf->address & PUD_MASK;
933 struct vm_area_struct *vma = vmf->vma;
936 * If we had pud_special, we could avoid all these restrictions,
937 * but we need to be consistent with PTEs and architectures that
938 * can't support a 'special' bit.
940 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
942 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
943 (VM_PFNMAP|VM_MIXEDMAP));
944 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
946 if (addr < vma->vm_start || addr >= vma->vm_end)
947 return VM_FAULT_SIGBUS;
949 track_pfn_insert(vma, &pgprot, pfn);
951 insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write);
952 return VM_FAULT_NOPAGE;
954 EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot);
955 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
957 static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
958 pmd_t *pmd, int flags)
962 _pmd = pmd_mkyoung(*pmd);
963 if (flags & FOLL_WRITE)
964 _pmd = pmd_mkdirty(_pmd);
965 if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
966 pmd, _pmd, flags & FOLL_WRITE))
967 update_mmu_cache_pmd(vma, addr, pmd);
970 struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
971 pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
973 unsigned long pfn = pmd_pfn(*pmd);
974 struct mm_struct *mm = vma->vm_mm;
977 assert_spin_locked(pmd_lockptr(mm, pmd));
980 * When we COW a devmap PMD entry, we split it into PTEs, so we should
981 * not be in this function with `flags & FOLL_COW` set.
983 WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
985 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
986 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
987 (FOLL_PIN | FOLL_GET)))
990 if (flags & FOLL_WRITE && !pmd_write(*pmd))
993 if (pmd_present(*pmd) && pmd_devmap(*pmd))
998 if (flags & FOLL_TOUCH)
999 touch_pmd(vma, addr, pmd, flags);
1002 * device mapped pages can only be returned if the
1003 * caller will manage the page reference count.
1005 if (!(flags & (FOLL_GET | FOLL_PIN)))
1006 return ERR_PTR(-EEXIST);
1008 pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT;
1009 *pgmap = get_dev_pagemap(pfn, *pgmap);
1011 return ERR_PTR(-EFAULT);
1012 page = pfn_to_page(pfn);
1013 if (!try_grab_page(page, flags))
1014 page = ERR_PTR(-ENOMEM);
1019 int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1020 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
1021 struct vm_area_struct *vma)
1023 spinlock_t *dst_ptl, *src_ptl;
1024 struct page *src_page;
1026 pgtable_t pgtable = NULL;
1029 /* Skip if can be re-fill on fault */
1030 if (!vma_is_anonymous(vma))
1033 pgtable = pte_alloc_one(dst_mm);
1034 if (unlikely(!pgtable))
1037 dst_ptl = pmd_lock(dst_mm, dst_pmd);
1038 src_ptl = pmd_lockptr(src_mm, src_pmd);
1039 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
1045 * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA
1046 * does not have the VM_UFFD_WP, which means that the uffd
1047 * fork event is not enabled.
1049 if (!(vma->vm_flags & VM_UFFD_WP))
1050 pmd = pmd_clear_uffd_wp(pmd);
1052 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1053 if (unlikely(is_swap_pmd(pmd))) {
1054 swp_entry_t entry = pmd_to_swp_entry(pmd);
1056 VM_BUG_ON(!is_pmd_migration_entry(pmd));
1057 if (is_write_migration_entry(entry)) {
1058 make_migration_entry_read(&entry);
1059 pmd = swp_entry_to_pmd(entry);
1060 if (pmd_swp_soft_dirty(*src_pmd))
1061 pmd = pmd_swp_mksoft_dirty(pmd);
1062 set_pmd_at(src_mm, addr, src_pmd, pmd);
1064 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
1065 mm_inc_nr_ptes(dst_mm);
1066 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
1067 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
1073 if (unlikely(!pmd_trans_huge(pmd))) {
1074 pte_free(dst_mm, pgtable);
1078 * When page table lock is held, the huge zero pmd should not be
1079 * under splitting since we don't split the page itself, only pmd to
1082 if (is_huge_zero_pmd(pmd)) {
1083 struct page *zero_page;
1085 * get_huge_zero_page() will never allocate a new page here,
1086 * since we already have a zero page to copy. It just takes a
1089 zero_page = mm_get_huge_zero_page(dst_mm);
1090 set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd,
1096 src_page = pmd_page(pmd);
1097 VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
1099 page_dup_rmap(src_page, true);
1100 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
1101 mm_inc_nr_ptes(dst_mm);
1102 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
1104 pmdp_set_wrprotect(src_mm, addr, src_pmd);
1105 pmd = pmd_mkold(pmd_wrprotect(pmd));
1106 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
1110 spin_unlock(src_ptl);
1111 spin_unlock(dst_ptl);
1116 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1117 static void touch_pud(struct vm_area_struct *vma, unsigned long addr,
1118 pud_t *pud, int flags)
1122 _pud = pud_mkyoung(*pud);
1123 if (flags & FOLL_WRITE)
1124 _pud = pud_mkdirty(_pud);
1125 if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK,
1126 pud, _pud, flags & FOLL_WRITE))
1127 update_mmu_cache_pud(vma, addr, pud);
1130 struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
1131 pud_t *pud, int flags, struct dev_pagemap **pgmap)
1133 unsigned long pfn = pud_pfn(*pud);
1134 struct mm_struct *mm = vma->vm_mm;
1137 assert_spin_locked(pud_lockptr(mm, pud));
1139 if (flags & FOLL_WRITE && !pud_write(*pud))
1142 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
1143 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
1144 (FOLL_PIN | FOLL_GET)))
1147 if (pud_present(*pud) && pud_devmap(*pud))
1152 if (flags & FOLL_TOUCH)
1153 touch_pud(vma, addr, pud, flags);
1156 * device mapped pages can only be returned if the
1157 * caller will manage the page reference count.
1159 * At least one of FOLL_GET | FOLL_PIN must be set, so assert that here:
1161 if (!(flags & (FOLL_GET | FOLL_PIN)))
1162 return ERR_PTR(-EEXIST);
1164 pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT;
1165 *pgmap = get_dev_pagemap(pfn, *pgmap);
1167 return ERR_PTR(-EFAULT);
1168 page = pfn_to_page(pfn);
1169 if (!try_grab_page(page, flags))
1170 page = ERR_PTR(-ENOMEM);
1175 int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1176 pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
1177 struct vm_area_struct *vma)
1179 spinlock_t *dst_ptl, *src_ptl;
1183 dst_ptl = pud_lock(dst_mm, dst_pud);
1184 src_ptl = pud_lockptr(src_mm, src_pud);
1185 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
1189 if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud)))
1193 * When page table lock is held, the huge zero pud should not be
1194 * under splitting since we don't split the page itself, only pud to
1197 if (is_huge_zero_pud(pud)) {
1198 /* No huge zero pud yet */
1201 pudp_set_wrprotect(src_mm, addr, src_pud);
1202 pud = pud_mkold(pud_wrprotect(pud));
1203 set_pud_at(dst_mm, addr, dst_pud, pud);
1207 spin_unlock(src_ptl);
1208 spin_unlock(dst_ptl);
1212 void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
1215 unsigned long haddr;
1216 bool write = vmf->flags & FAULT_FLAG_WRITE;
1218 vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud);
1219 if (unlikely(!pud_same(*vmf->pud, orig_pud)))
1222 entry = pud_mkyoung(orig_pud);
1224 entry = pud_mkdirty(entry);
1225 haddr = vmf->address & HPAGE_PUD_MASK;
1226 if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write))
1227 update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud);
1230 spin_unlock(vmf->ptl);
1232 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
1234 void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd)
1237 unsigned long haddr;
1238 bool write = vmf->flags & FAULT_FLAG_WRITE;
1240 vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
1241 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd)))
1244 entry = pmd_mkyoung(orig_pmd);
1246 entry = pmd_mkdirty(entry);
1247 haddr = vmf->address & HPAGE_PMD_MASK;
1248 if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write))
1249 update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd);
1252 spin_unlock(vmf->ptl);
1255 vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
1257 struct vm_area_struct *vma = vmf->vma;
1259 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
1261 vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd);
1262 VM_BUG_ON_VMA(!vma->anon_vma, vma);
1264 if (is_huge_zero_pmd(orig_pmd))
1267 spin_lock(vmf->ptl);
1269 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) {
1270 spin_unlock(vmf->ptl);
1274 page = pmd_page(orig_pmd);
1275 VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page);
1277 /* Lock page for reuse_swap_page() */
1278 if (!trylock_page(page)) {
1280 spin_unlock(vmf->ptl);
1282 spin_lock(vmf->ptl);
1283 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) {
1284 spin_unlock(vmf->ptl);
1293 * We can only reuse the page if nobody else maps the huge page or it's
1296 if (reuse_swap_page(page, NULL)) {
1298 entry = pmd_mkyoung(orig_pmd);
1299 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1300 if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1))
1301 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
1303 spin_unlock(vmf->ptl);
1304 return VM_FAULT_WRITE;
1308 spin_unlock(vmf->ptl);
1310 __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL);
1311 return VM_FAULT_FALLBACK;
1315 * FOLL_FORCE or a forced COW break can write even to unwritable pmd's,
1316 * but only after we've gone through a COW cycle and they are dirty.
1318 static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
1320 return pmd_write(pmd) || ((flags & FOLL_COW) && pmd_dirty(pmd));
1323 struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
1328 struct mm_struct *mm = vma->vm_mm;
1329 struct page *page = NULL;
1331 assert_spin_locked(pmd_lockptr(mm, pmd));
1333 if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags))
1336 /* Avoid dumping huge zero page */
1337 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1338 return ERR_PTR(-EFAULT);
1340 /* Full NUMA hinting faults to serialise migration in fault paths */
1341 if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
1344 page = pmd_page(*pmd);
1345 VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page);
1347 if (!try_grab_page(page, flags))
1348 return ERR_PTR(-ENOMEM);
1350 if (flags & FOLL_TOUCH)
1351 touch_pmd(vma, addr, pmd, flags);
1353 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1355 * We don't mlock() pte-mapped THPs. This way we can avoid
1356 * leaking mlocked pages into non-VM_LOCKED VMAs.
1360 * In most cases the pmd is the only mapping of the page as we
1361 * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for
1362 * writable private mappings in populate_vma_page_range().
1364 * The only scenario when we have the page shared here is if we
1365 * mlocking read-only mapping shared over fork(). We skip
1366 * mlocking such pages.
1370 * We can expect PageDoubleMap() to be stable under page lock:
1371 * for file pages we set it in page_add_file_rmap(), which
1372 * requires page to be locked.
1375 if (PageAnon(page) && compound_mapcount(page) != 1)
1377 if (PageDoubleMap(page) || !page->mapping)
1379 if (!trylock_page(page))
1381 if (page->mapping && !PageDoubleMap(page))
1382 mlock_vma_page(page);
1386 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1387 VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page);
1393 /* NUMA hinting page fault entry point for trans huge pmds */
1394 vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
1396 struct vm_area_struct *vma = vmf->vma;
1397 struct anon_vma *anon_vma = NULL;
1399 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
1400 int page_nid = NUMA_NO_NODE, this_nid = numa_node_id();
1401 int target_nid, last_cpupid = -1;
1403 bool migrated = false;
1407 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
1408 if (unlikely(!pmd_same(pmd, *vmf->pmd)))
1412 * If there are potential migrations, wait for completion and retry
1413 * without disrupting NUMA hinting information. Do not relock and
1414 * check_same as the page may no longer be mapped.
1416 if (unlikely(pmd_trans_migrating(*vmf->pmd))) {
1417 page = pmd_page(*vmf->pmd);
1418 if (!get_page_unless_zero(page))
1420 spin_unlock(vmf->ptl);
1421 put_and_wait_on_page_locked(page);
1425 page = pmd_page(pmd);
1426 BUG_ON(is_huge_zero_page(page));
1427 page_nid = page_to_nid(page);
1428 last_cpupid = page_cpupid_last(page);
1429 count_vm_numa_event(NUMA_HINT_FAULTS);
1430 if (page_nid == this_nid) {
1431 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
1432 flags |= TNF_FAULT_LOCAL;
1435 /* See similar comment in do_numa_page for explanation */
1436 if (!pmd_savedwrite(pmd))
1437 flags |= TNF_NO_GROUP;
1440 * Acquire the page lock to serialise THP migrations but avoid dropping
1441 * page_table_lock if at all possible
1443 page_locked = trylock_page(page);
1444 target_nid = mpol_misplaced(page, vma, haddr);
1445 if (target_nid == NUMA_NO_NODE) {
1446 /* If the page was locked, there are no parallel migrations */
1451 /* Migration could have started since the pmd_trans_migrating check */
1453 page_nid = NUMA_NO_NODE;
1454 if (!get_page_unless_zero(page))
1456 spin_unlock(vmf->ptl);
1457 put_and_wait_on_page_locked(page);
1462 * Page is misplaced. Page lock serialises migrations. Acquire anon_vma
1463 * to serialises splits
1466 spin_unlock(vmf->ptl);
1467 anon_vma = page_lock_anon_vma_read(page);
1469 /* Confirm the PMD did not change while page_table_lock was released */
1470 spin_lock(vmf->ptl);
1471 if (unlikely(!pmd_same(pmd, *vmf->pmd))) {
1474 page_nid = NUMA_NO_NODE;
1478 /* Bail if we fail to protect against THP splits for any reason */
1479 if (unlikely(!anon_vma)) {
1481 page_nid = NUMA_NO_NODE;
1486 * Since we took the NUMA fault, we must have observed the !accessible
1487 * bit. Make sure all other CPUs agree with that, to avoid them
1488 * modifying the page we're about to migrate.
1490 * Must be done under PTL such that we'll observe the relevant
1491 * inc_tlb_flush_pending().
1493 * We are not sure a pending tlb flush here is for a huge page
1494 * mapping or not. Hence use the tlb range variant
1496 if (mm_tlb_flush_pending(vma->vm_mm)) {
1497 flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
1499 * change_huge_pmd() released the pmd lock before
1500 * invalidating the secondary MMUs sharing the primary
1501 * MMU pagetables (with ->invalidate_range()). The
1502 * mmu_notifier_invalidate_range_end() (which
1503 * internally calls ->invalidate_range()) in
1504 * change_pmd_range() will run after us, so we can't
1505 * rely on it here and we need an explicit invalidate.
1507 mmu_notifier_invalidate_range(vma->vm_mm, haddr,
1508 haddr + HPAGE_PMD_SIZE);
1512 * Migrate the THP to the requested node, returns with page unlocked
1513 * and access rights restored.
1515 spin_unlock(vmf->ptl);
1517 migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma,
1518 vmf->pmd, pmd, vmf->address, page, target_nid);
1520 flags |= TNF_MIGRATED;
1521 page_nid = target_nid;
1523 flags |= TNF_MIGRATE_FAIL;
1527 BUG_ON(!PageLocked(page));
1528 was_writable = pmd_savedwrite(pmd);
1529 pmd = pmd_modify(pmd, vma->vm_page_prot);
1530 pmd = pmd_mkyoung(pmd);
1532 pmd = pmd_mkwrite(pmd);
1533 set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd);
1534 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
1537 spin_unlock(vmf->ptl);
1541 page_unlock_anon_vma_read(anon_vma);
1543 if (page_nid != NUMA_NO_NODE)
1544 task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR,
1551 * Return true if we do MADV_FREE successfully on entire pmd page.
1552 * Otherwise, return false.
1554 bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1555 pmd_t *pmd, unsigned long addr, unsigned long next)
1560 struct mm_struct *mm = tlb->mm;
1563 tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
1565 ptl = pmd_trans_huge_lock(pmd, vma);
1570 if (is_huge_zero_pmd(orig_pmd))
1573 if (unlikely(!pmd_present(orig_pmd))) {
1574 VM_BUG_ON(thp_migration_supported() &&
1575 !is_pmd_migration_entry(orig_pmd));
1579 page = pmd_page(orig_pmd);
1581 * If other processes are mapping this page, we couldn't discard
1582 * the page unless they all do MADV_FREE so let's skip the page.
1584 if (page_mapcount(page) != 1)
1587 if (!trylock_page(page))
1591 * If user want to discard part-pages of THP, split it so MADV_FREE
1592 * will deactivate only them.
1594 if (next - addr != HPAGE_PMD_SIZE) {
1597 split_huge_page(page);
1603 if (PageDirty(page))
1604 ClearPageDirty(page);
1607 if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
1608 pmdp_invalidate(vma, addr, pmd);
1609 orig_pmd = pmd_mkold(orig_pmd);
1610 orig_pmd = pmd_mkclean(orig_pmd);
1612 set_pmd_at(mm, addr, pmd, orig_pmd);
1613 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1616 mark_page_lazyfree(page);
1624 static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
1628 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1629 pte_free(mm, pgtable);
1633 int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1634 pmd_t *pmd, unsigned long addr)
1639 tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
1641 ptl = __pmd_trans_huge_lock(pmd, vma);
1645 * For architectures like ppc64 we look at deposited pgtable
1646 * when calling pmdp_huge_get_and_clear. So do the
1647 * pgtable_trans_huge_withdraw after finishing pmdp related
1650 orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd,
1652 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1653 if (vma_is_special_huge(vma)) {
1654 if (arch_needs_pgtable_deposit())
1655 zap_deposited_table(tlb->mm, pmd);
1657 if (is_huge_zero_pmd(orig_pmd))
1658 tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
1659 } else if (is_huge_zero_pmd(orig_pmd)) {
1660 zap_deposited_table(tlb->mm, pmd);
1662 tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
1664 struct page *page = NULL;
1665 int flush_needed = 1;
1667 if (pmd_present(orig_pmd)) {
1668 page = pmd_page(orig_pmd);
1669 page_remove_rmap(page, true);
1670 VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
1671 VM_BUG_ON_PAGE(!PageHead(page), page);
1672 } else if (thp_migration_supported()) {
1675 VM_BUG_ON(!is_pmd_migration_entry(orig_pmd));
1676 entry = pmd_to_swp_entry(orig_pmd);
1677 page = pfn_to_page(swp_offset(entry));
1680 WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
1682 if (PageAnon(page)) {
1683 zap_deposited_table(tlb->mm, pmd);
1684 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1686 if (arch_needs_pgtable_deposit())
1687 zap_deposited_table(tlb->mm, pmd);
1688 add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR);
1693 tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE);
1698 #ifndef pmd_move_must_withdraw
1699 static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
1700 spinlock_t *old_pmd_ptl,
1701 struct vm_area_struct *vma)
1704 * With split pmd lock we also need to move preallocated
1705 * PTE page table if new_pmd is on different PMD page table.
1707 * We also don't deposit and withdraw tables for file pages.
1709 return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma);
1713 static pmd_t move_soft_dirty_pmd(pmd_t pmd)
1715 #ifdef CONFIG_MEM_SOFT_DIRTY
1716 if (unlikely(is_pmd_migration_entry(pmd)))
1717 pmd = pmd_swp_mksoft_dirty(pmd);
1718 else if (pmd_present(pmd))
1719 pmd = pmd_mksoft_dirty(pmd);
1724 bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
1725 unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd)
1727 spinlock_t *old_ptl, *new_ptl;
1729 struct mm_struct *mm = vma->vm_mm;
1730 bool force_flush = false;
1733 * The destination pmd shouldn't be established, free_pgtables()
1734 * should have release it.
1736 if (WARN_ON(!pmd_none(*new_pmd))) {
1737 VM_BUG_ON(pmd_trans_huge(*new_pmd));
1742 * We don't have to worry about the ordering of src and dst
1743 * ptlocks because exclusive mmap_lock prevents deadlock.
1745 old_ptl = __pmd_trans_huge_lock(old_pmd, vma);
1747 new_ptl = pmd_lockptr(mm, new_pmd);
1748 if (new_ptl != old_ptl)
1749 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
1750 pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd);
1751 if (pmd_present(pmd))
1753 VM_BUG_ON(!pmd_none(*new_pmd));
1755 if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) {
1757 pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
1758 pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
1760 pmd = move_soft_dirty_pmd(pmd);
1761 set_pmd_at(mm, new_addr, new_pmd, pmd);
1763 flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE);
1764 if (new_ptl != old_ptl)
1765 spin_unlock(new_ptl);
1766 spin_unlock(old_ptl);
1774 * - 0 if PMD could not be locked
1775 * - 1 if PMD was locked but protections unchange and TLB flush unnecessary
1776 * - HPAGE_PMD_NR is protections changed and TLB flush necessary
1778 int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1779 unsigned long addr, pgprot_t newprot, unsigned long cp_flags)
1781 struct mm_struct *mm = vma->vm_mm;
1784 bool preserve_write;
1786 bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
1787 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
1788 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
1790 ptl = __pmd_trans_huge_lock(pmd, vma);
1794 preserve_write = prot_numa && pmd_write(*pmd);
1797 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1798 if (is_swap_pmd(*pmd)) {
1799 swp_entry_t entry = pmd_to_swp_entry(*pmd);
1801 VM_BUG_ON(!is_pmd_migration_entry(*pmd));
1802 if (is_write_migration_entry(entry)) {
1805 * A protection check is difficult so
1806 * just be safe and disable write
1808 make_migration_entry_read(&entry);
1809 newpmd = swp_entry_to_pmd(entry);
1810 if (pmd_swp_soft_dirty(*pmd))
1811 newpmd = pmd_swp_mksoft_dirty(newpmd);
1812 set_pmd_at(mm, addr, pmd, newpmd);
1819 * Avoid trapping faults against the zero page. The read-only
1820 * data is likely to be read-cached on the local CPU and
1821 * local/remote hits to the zero page are not interesting.
1823 if (prot_numa && is_huge_zero_pmd(*pmd))
1826 if (prot_numa && pmd_protnone(*pmd))
1830 * In case prot_numa, we are under mmap_read_lock(mm). It's critical
1831 * to not clear pmd intermittently to avoid race with MADV_DONTNEED
1832 * which is also under mmap_read_lock(mm):
1835 * change_huge_pmd(prot_numa=1)
1836 * pmdp_huge_get_and_clear_notify()
1837 * madvise_dontneed()
1839 * pmd_trans_huge(*pmd) == 0 (without ptl)
1842 * // pmd is re-established
1844 * The race makes MADV_DONTNEED miss the huge pmd and don't clear it
1845 * which may break userspace.
1847 * pmdp_invalidate() is required to make sure we don't miss
1848 * dirty/young flags set by hardware.
1850 entry = pmdp_invalidate(vma, addr, pmd);
1852 entry = pmd_modify(entry, newprot);
1854 entry = pmd_mk_savedwrite(entry);
1856 entry = pmd_wrprotect(entry);
1857 entry = pmd_mkuffd_wp(entry);
1858 } else if (uffd_wp_resolve) {
1860 * Leave the write bit to be handled by PF interrupt
1861 * handler, then things like COW could be properly
1864 entry = pmd_clear_uffd_wp(entry);
1867 set_pmd_at(mm, addr, pmd, entry);
1868 BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry));
1875 * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise.
1877 * Note that if it returns page table lock pointer, this routine returns without
1878 * unlocking page table lock. So callers must unlock it.
1880 spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
1883 ptl = pmd_lock(vma->vm_mm, pmd);
1884 if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) ||
1892 * Returns true if a given pud maps a thp, false otherwise.
1894 * Note that if it returns true, this routine returns without unlocking page
1895 * table lock. So callers must unlock it.
1897 spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma)
1901 ptl = pud_lock(vma->vm_mm, pud);
1902 if (likely(pud_trans_huge(*pud) || pud_devmap(*pud)))
1908 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1909 int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
1910 pud_t *pud, unsigned long addr)
1914 ptl = __pud_trans_huge_lock(pud, vma);
1918 * For architectures like ppc64 we look at deposited pgtable
1919 * when calling pudp_huge_get_and_clear. So do the
1920 * pgtable_trans_huge_withdraw after finishing pudp related
1923 pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm);
1924 tlb_remove_pud_tlb_entry(tlb, pud, addr);
1925 if (vma_is_special_huge(vma)) {
1927 /* No zero page support yet */
1929 /* No support for anonymous PUD pages yet */
1935 static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
1936 unsigned long haddr)
1938 VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);
1939 VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
1940 VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);
1941 VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud));
1943 count_vm_event(THP_SPLIT_PUD);
1945 pudp_huge_clear_flush_notify(vma, haddr, pud);
1948 void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
1949 unsigned long address)
1952 struct mmu_notifier_range range;
1954 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
1955 address & HPAGE_PUD_MASK,
1956 (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE);
1957 mmu_notifier_invalidate_range_start(&range);
1958 ptl = pud_lock(vma->vm_mm, pud);
1959 if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud)))
1961 __split_huge_pud_locked(vma, pud, range.start);
1966 * No need to double call mmu_notifier->invalidate_range() callback as
1967 * the above pudp_huge_clear_flush_notify() did already call it.
1969 mmu_notifier_invalidate_range_only_end(&range);
1971 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
1973 static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
1974 unsigned long haddr, pmd_t *pmd)
1976 struct mm_struct *mm = vma->vm_mm;
1982 * Leave pmd empty until pte is filled note that it is fine to delay
1983 * notification until mmu_notifier_invalidate_range_end() as we are
1984 * replacing a zero pmd write protected page with a zero pte write
1987 * See Documentation/vm/mmu_notifier.rst
1989 pmdp_huge_clear_flush(vma, haddr, pmd);
1991 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1992 pmd_populate(mm, &_pmd, pgtable);
1994 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1996 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
1997 entry = pte_mkspecial(entry);
1998 pte = pte_offset_map(&_pmd, haddr);
1999 VM_BUG_ON(!pte_none(*pte));
2000 set_pte_at(mm, haddr, pte, entry);
2003 smp_wmb(); /* make pte visible before pmd */
2004 pmd_populate(mm, pmd, pgtable);
2007 static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
2008 unsigned long haddr, bool freeze)
2010 struct mm_struct *mm = vma->vm_mm;
2013 pmd_t old_pmd, _pmd;
2014 bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false;
2018 VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
2019 VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
2020 VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
2021 VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)
2022 && !pmd_devmap(*pmd));
2024 count_vm_event(THP_SPLIT_PMD);
2026 if (!vma_is_anonymous(vma)) {
2027 _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
2029 * We are going to unmap this huge page. So
2030 * just go ahead and zap it
2032 if (arch_needs_pgtable_deposit())
2033 zap_deposited_table(mm, pmd);
2034 if (vma_is_special_huge(vma))
2036 page = pmd_page(_pmd);
2037 if (!PageDirty(page) && pmd_dirty(_pmd))
2038 set_page_dirty(page);
2039 if (!PageReferenced(page) && pmd_young(_pmd))
2040 SetPageReferenced(page);
2041 page_remove_rmap(page, true);
2043 add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR);
2045 } else if (is_huge_zero_pmd(*pmd)) {
2047 * FIXME: Do we want to invalidate secondary mmu by calling
2048 * mmu_notifier_invalidate_range() see comments below inside
2049 * __split_huge_pmd() ?
2051 * We are going from a zero huge page write protected to zero
2052 * small page also write protected so it does not seems useful
2053 * to invalidate secondary mmu at this time.
2055 return __split_huge_zero_page_pmd(vma, haddr, pmd);
2059 * Up to this point the pmd is present and huge and userland has the
2060 * whole access to the hugepage during the split (which happens in
2061 * place). If we overwrite the pmd with the not-huge version pointing
2062 * to the pte here (which of course we could if all CPUs were bug
2063 * free), userland could trigger a small page size TLB miss on the
2064 * small sized TLB while the hugepage TLB entry is still established in
2065 * the huge TLB. Some CPU doesn't like that.
2066 * See http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf, Erratum
2067 * 383 on page 105. Intel should be safe but is also warns that it's
2068 * only safe if the permission and cache attributes of the two entries
2069 * loaded in the two TLB is identical (which should be the case here).
2070 * But it is generally safer to never allow small and huge TLB entries
2071 * for the same virtual address to be loaded simultaneously. So instead
2072 * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the
2073 * current pmd notpresent (atomically because here the pmd_trans_huge
2074 * must remain set at all times on the pmd until the split is complete
2075 * for this pmd), then we flush the SMP TLB and finally we write the
2076 * non-huge version of the pmd entry with pmd_populate.
2078 old_pmd = pmdp_invalidate(vma, haddr, pmd);
2080 pmd_migration = is_pmd_migration_entry(old_pmd);
2081 if (unlikely(pmd_migration)) {
2084 entry = pmd_to_swp_entry(old_pmd);
2085 page = pfn_to_page(swp_offset(entry));
2086 write = is_write_migration_entry(entry);
2088 soft_dirty = pmd_swp_soft_dirty(old_pmd);
2089 uffd_wp = pmd_swp_uffd_wp(old_pmd);
2091 page = pmd_page(old_pmd);
2092 if (pmd_dirty(old_pmd))
2094 write = pmd_write(old_pmd);
2095 young = pmd_young(old_pmd);
2096 soft_dirty = pmd_soft_dirty(old_pmd);
2097 uffd_wp = pmd_uffd_wp(old_pmd);
2099 VM_BUG_ON_PAGE(!page_count(page), page);
2100 page_ref_add(page, HPAGE_PMD_NR - 1);
2103 * Withdraw the table only after we mark the pmd entry invalid.
2104 * This's critical for some architectures (Power).
2106 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
2107 pmd_populate(mm, &_pmd, pgtable);
2109 for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
2112 * Note that NUMA hinting access restrictions are not
2113 * transferred to avoid any possibility of altering
2114 * permissions across VMAs.
2116 if (freeze || pmd_migration) {
2117 swp_entry_t swp_entry;
2118 swp_entry = make_migration_entry(page + i, write);
2119 entry = swp_entry_to_pte(swp_entry);
2121 entry = pte_swp_mksoft_dirty(entry);
2123 entry = pte_swp_mkuffd_wp(entry);
2125 entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot));
2126 entry = maybe_mkwrite(entry, vma);
2128 entry = pte_wrprotect(entry);
2130 entry = pte_mkold(entry);
2132 entry = pte_mksoft_dirty(entry);
2134 entry = pte_mkuffd_wp(entry);
2136 pte = pte_offset_map(&_pmd, addr);
2137 BUG_ON(!pte_none(*pte));
2138 set_pte_at(mm, addr, pte, entry);
2139 atomic_inc(&page[i]._mapcount);
2144 * Set PG_double_map before dropping compound_mapcount to avoid
2145 * false-negative page_mapped().
2147 if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) {
2148 for (i = 0; i < HPAGE_PMD_NR; i++)
2149 atomic_inc(&page[i]._mapcount);
2152 lock_page_memcg(page);
2153 if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
2154 /* Last compound_mapcount is gone. */
2155 __dec_lruvec_page_state(page, NR_ANON_THPS);
2156 if (TestClearPageDoubleMap(page)) {
2157 /* No need in mapcount reference anymore */
2158 for (i = 0; i < HPAGE_PMD_NR; i++)
2159 atomic_dec(&page[i]._mapcount);
2162 unlock_page_memcg(page);
2164 smp_wmb(); /* make pte visible before pmd */
2165 pmd_populate(mm, pmd, pgtable);
2168 for (i = 0; i < HPAGE_PMD_NR; i++) {
2169 page_remove_rmap(page + i, false);
2175 void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
2176 unsigned long address, bool freeze, struct page *page)
2179 struct mmu_notifier_range range;
2180 bool was_locked = false;
2183 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
2184 address & HPAGE_PMD_MASK,
2185 (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE);
2186 mmu_notifier_invalidate_range_start(&range);
2187 ptl = pmd_lock(vma->vm_mm, pmd);
2190 * If caller asks to setup a migration entries, we need a page to check
2191 * pmd against. Otherwise we can end up replacing wrong page.
2193 VM_BUG_ON(freeze && !page);
2195 VM_WARN_ON_ONCE(!PageLocked(page));
2197 if (page != pmd_page(*pmd))
2202 if (pmd_trans_huge(*pmd)) {
2204 page = pmd_page(*pmd);
2205 if (unlikely(!trylock_page(page))) {
2211 if (unlikely(!pmd_same(*pmd, _pmd))) {
2220 if (PageMlocked(page))
2221 clear_page_mlock(page);
2222 } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
2224 __split_huge_pmd_locked(vma, pmd, range.start, freeze);
2227 if (!was_locked && page)
2230 * No need to double call mmu_notifier->invalidate_range() callback.
2231 * They are 3 cases to consider inside __split_huge_pmd_locked():
2232 * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious
2233 * 2) __split_huge_zero_page_pmd() read only zero page and any write
2234 * fault will trigger a flush_notify before pointing to a new page
2235 * (it is fine if the secondary mmu keeps pointing to the old zero
2236 * page in the meantime)
2237 * 3) Split a huge pmd into pte pointing to the same page. No need
2238 * to invalidate secondary tlb entry they are all still valid.
2239 * any further changes to individual pte will notify. So no need
2240 * to call mmu_notifier->invalidate_range()
2242 mmu_notifier_invalidate_range_only_end(&range);
2245 void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
2246 bool freeze, struct page *page)
2253 pgd = pgd_offset(vma->vm_mm, address);
2254 if (!pgd_present(*pgd))
2257 p4d = p4d_offset(pgd, address);
2258 if (!p4d_present(*p4d))
2261 pud = pud_offset(p4d, address);
2262 if (!pud_present(*pud))
2265 pmd = pmd_offset(pud, address);
2267 __split_huge_pmd(vma, pmd, address, freeze, page);
2270 void vma_adjust_trans_huge(struct vm_area_struct *vma,
2271 unsigned long start,
2276 * If the new start address isn't hpage aligned and it could
2277 * previously contain an hugepage: check if we need to split
2280 if (start & ~HPAGE_PMD_MASK &&
2281 (start & HPAGE_PMD_MASK) >= vma->vm_start &&
2282 (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2283 split_huge_pmd_address(vma, start, false, NULL);
2286 * If the new end address isn't hpage aligned and it could
2287 * previously contain an hugepage: check if we need to split
2290 if (end & ~HPAGE_PMD_MASK &&
2291 (end & HPAGE_PMD_MASK) >= vma->vm_start &&
2292 (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
2293 split_huge_pmd_address(vma, end, false, NULL);
2296 * If we're also updating the vma->vm_next->vm_start, if the new
2297 * vm_next->vm_start isn't page aligned and it could previously
2298 * contain an hugepage: check if we need to split an huge pmd.
2300 if (adjust_next > 0) {
2301 struct vm_area_struct *next = vma->vm_next;
2302 unsigned long nstart = next->vm_start;
2303 nstart += adjust_next << PAGE_SHIFT;
2304 if (nstart & ~HPAGE_PMD_MASK &&
2305 (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
2306 (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
2307 split_huge_pmd_address(next, nstart, false, NULL);
2311 static void unmap_page(struct page *page)
2313 enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
2314 TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD;
2317 VM_BUG_ON_PAGE(!PageHead(page), page);
2320 ttu_flags |= TTU_SPLIT_FREEZE;
2322 unmap_success = try_to_unmap(page, ttu_flags);
2323 VM_BUG_ON_PAGE(!unmap_success, page);
2326 static void remap_page(struct page *page)
2329 if (PageTransHuge(page)) {
2330 remove_migration_ptes(page, page, true);
2332 for (i = 0; i < HPAGE_PMD_NR; i++)
2333 remove_migration_ptes(page + i, page + i, true);
2337 static void __split_huge_page_tail(struct page *head, int tail,
2338 struct lruvec *lruvec, struct list_head *list)
2340 struct page *page_tail = head + tail;
2342 VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail);
2345 * Clone page flags before unfreezing refcount.
2347 * After successful get_page_unless_zero() might follow flags change,
2348 * for exmaple lock_page() which set PG_waiters.
2350 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
2351 page_tail->flags |= (head->flags &
2352 ((1L << PG_referenced) |
2353 (1L << PG_swapbacked) |
2354 (1L << PG_swapcache) |
2355 (1L << PG_mlocked) |
2356 (1L << PG_uptodate) |
2358 (1L << PG_workingset) |
2360 (1L << PG_unevictable) |
2363 /* ->mapping in first tail page is compound_mapcount */
2364 VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
2366 page_tail->mapping = head->mapping;
2367 page_tail->index = head->index + tail;
2369 /* Page flags must be visible before we make the page non-compound. */
2373 * Clear PageTail before unfreezing page refcount.
2375 * After successful get_page_unless_zero() might follow put_page()
2376 * which needs correct compound_head().
2378 clear_compound_head(page_tail);
2380 /* Finally unfreeze refcount. Additional reference from page cache. */
2381 page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) ||
2382 PageSwapCache(head)));
2384 if (page_is_young(head))
2385 set_page_young(page_tail);
2386 if (page_is_idle(head))
2387 set_page_idle(page_tail);
2389 page_cpupid_xchg_last(page_tail, page_cpupid_last(head));
2392 * always add to the tail because some iterators expect new
2393 * pages to show after the currently processed elements - e.g.
2396 lru_add_page_tail(head, page_tail, lruvec, list);
2399 static void __split_huge_page(struct page *page, struct list_head *list,
2400 pgoff_t end, unsigned long flags)
2402 struct page *head = compound_head(page);
2403 pg_data_t *pgdat = page_pgdat(head);
2404 struct lruvec *lruvec;
2405 struct address_space *swap_cache = NULL;
2406 unsigned long offset = 0;
2409 lruvec = mem_cgroup_page_lruvec(head, pgdat);
2411 /* complete memcg works before add pages to LRU */
2412 mem_cgroup_split_huge_fixup(head);
2414 if (PageAnon(head) && PageSwapCache(head)) {
2415 swp_entry_t entry = { .val = page_private(head) };
2417 offset = swp_offset(entry);
2418 swap_cache = swap_address_space(entry);
2419 xa_lock(&swap_cache->i_pages);
2422 for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
2423 __split_huge_page_tail(head, i, lruvec, list);
2424 /* Some pages can be beyond i_size: drop them from page cache */
2425 if (head[i].index >= end) {
2426 ClearPageDirty(head + i);
2427 __delete_from_page_cache(head + i, NULL);
2428 if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
2429 shmem_uncharge(head->mapping->host, 1);
2431 } else if (!PageAnon(page)) {
2432 __xa_store(&head->mapping->i_pages, head[i].index,
2434 } else if (swap_cache) {
2435 __xa_store(&swap_cache->i_pages, offset + i,
2440 ClearPageCompound(head);
2442 split_page_owner(head, HPAGE_PMD_ORDER);
2444 /* See comment in __split_huge_page_tail() */
2445 if (PageAnon(head)) {
2446 /* Additional pin to swap cache */
2447 if (PageSwapCache(head)) {
2448 page_ref_add(head, 2);
2449 xa_unlock(&swap_cache->i_pages);
2454 /* Additional pin to page cache */
2455 page_ref_add(head, 2);
2456 xa_unlock(&head->mapping->i_pages);
2459 spin_unlock_irqrestore(&pgdat->lru_lock, flags);
2463 for (i = 0; i < HPAGE_PMD_NR; i++) {
2464 struct page *subpage = head + i;
2465 if (subpage == page)
2467 unlock_page(subpage);
2470 * Subpages may be freed if there wasn't any mapping
2471 * like if add_to_swap() is running on a lru page that
2472 * had its mapping zapped. And freeing these pages
2473 * requires taking the lru_lock so we do the put_page
2474 * of the tail pages after the split is complete.
2480 int total_mapcount(struct page *page)
2482 int i, compound, ret;
2484 VM_BUG_ON_PAGE(PageTail(page), page);
2486 if (likely(!PageCompound(page)))
2487 return atomic_read(&page->_mapcount) + 1;
2489 compound = compound_mapcount(page);
2493 for (i = 0; i < HPAGE_PMD_NR; i++)
2494 ret += atomic_read(&page[i]._mapcount) + 1;
2495 /* File pages has compound_mapcount included in _mapcount */
2496 if (!PageAnon(page))
2497 return ret - compound * HPAGE_PMD_NR;
2498 if (PageDoubleMap(page))
2499 ret -= HPAGE_PMD_NR;
2504 * This calculates accurately how many mappings a transparent hugepage
2505 * has (unlike page_mapcount() which isn't fully accurate). This full
2506 * accuracy is primarily needed to know if copy-on-write faults can
2507 * reuse the page and change the mapping to read-write instead of
2508 * copying them. At the same time this returns the total_mapcount too.
2510 * The function returns the highest mapcount any one of the subpages
2511 * has. If the return value is one, even if different processes are
2512 * mapping different subpages of the transparent hugepage, they can
2513 * all reuse it, because each process is reusing a different subpage.
2515 * The total_mapcount is instead counting all virtual mappings of the
2516 * subpages. If the total_mapcount is equal to "one", it tells the
2517 * caller all mappings belong to the same "mm" and in turn the
2518 * anon_vma of the transparent hugepage can become the vma->anon_vma
2519 * local one as no other process may be mapping any of the subpages.
2521 * It would be more accurate to replace page_mapcount() with
2522 * page_trans_huge_mapcount(), however we only use
2523 * page_trans_huge_mapcount() in the copy-on-write faults where we
2524 * need full accuracy to avoid breaking page pinning, because
2525 * page_trans_huge_mapcount() is slower than page_mapcount().
2527 int page_trans_huge_mapcount(struct page *page, int *total_mapcount)
2529 int i, ret, _total_mapcount, mapcount;
2531 /* hugetlbfs shouldn't call it */
2532 VM_BUG_ON_PAGE(PageHuge(page), page);
2534 if (likely(!PageTransCompound(page))) {
2535 mapcount = atomic_read(&page->_mapcount) + 1;
2537 *total_mapcount = mapcount;
2541 page = compound_head(page);
2543 _total_mapcount = ret = 0;
2544 for (i = 0; i < HPAGE_PMD_NR; i++) {
2545 mapcount = atomic_read(&page[i]._mapcount) + 1;
2546 ret = max(ret, mapcount);
2547 _total_mapcount += mapcount;
2549 if (PageDoubleMap(page)) {
2551 _total_mapcount -= HPAGE_PMD_NR;
2553 mapcount = compound_mapcount(page);
2555 _total_mapcount += mapcount;
2557 *total_mapcount = _total_mapcount;
2561 /* Racy check whether the huge page can be split */
2562 bool can_split_huge_page(struct page *page, int *pextra_pins)
2566 /* Additional pins from page cache */
2568 extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0;
2570 extra_pins = HPAGE_PMD_NR;
2572 *pextra_pins = extra_pins;
2573 return total_mapcount(page) == page_count(page) - extra_pins - 1;
2577 * This function splits huge page into normal pages. @page can point to any
2578 * subpage of huge page to split. Split doesn't change the position of @page.
2580 * Only caller must hold pin on the @page, otherwise split fails with -EBUSY.
2581 * The huge page must be locked.
2583 * If @list is null, tail pages will be added to LRU list, otherwise, to @list.
2585 * Both head page and tail pages will inherit mapping, flags, and so on from
2588 * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if
2589 * they are not mapped.
2591 * Returns 0 if the hugepage is split successfully.
2592 * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under
2595 int split_huge_page_to_list(struct page *page, struct list_head *list)
2597 struct page *head = compound_head(page);
2598 struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
2599 struct deferred_split *ds_queue = get_deferred_split_queue(head);
2600 struct anon_vma *anon_vma = NULL;
2601 struct address_space *mapping = NULL;
2602 int count, mapcount, extra_pins, ret;
2603 unsigned long flags;
2606 VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
2607 VM_BUG_ON_PAGE(!PageLocked(head), head);
2608 VM_BUG_ON_PAGE(!PageCompound(head), head);
2610 if (PageWriteback(head))
2613 if (PageAnon(head)) {
2615 * The caller does not necessarily hold an mmap_lock that would
2616 * prevent the anon_vma disappearing so we first we take a
2617 * reference to it and then lock the anon_vma for write. This
2618 * is similar to page_lock_anon_vma_read except the write lock
2619 * is taken to serialise against parallel split or collapse
2622 anon_vma = page_get_anon_vma(head);
2629 anon_vma_lock_write(anon_vma);
2631 mapping = head->mapping;
2640 i_mmap_lock_read(mapping);
2643 *__split_huge_page() may need to trim off pages beyond EOF:
2644 * but on 32-bit, i_size_read() takes an irq-unsafe seqlock,
2645 * which cannot be nested inside the page tree lock. So note
2646 * end now: i_size itself may be changed at any moment, but
2647 * head page lock is good enough to serialize the trimming.
2649 end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE);
2653 * Racy check if we can split the page, before unmap_page() will
2656 if (!can_split_huge_page(head, &extra_pins)) {
2662 VM_BUG_ON_PAGE(compound_mapcount(head), head);
2664 /* prevent PageLRU to go away from under us, and freeze lru stats */
2665 spin_lock_irqsave(&pgdata->lru_lock, flags);
2668 XA_STATE(xas, &mapping->i_pages, page_index(head));
2671 * Check if the head page is present in page cache.
2672 * We assume all tail are present too, if head is there.
2674 xa_lock(&mapping->i_pages);
2675 if (xas_load(&xas) != head)
2679 /* Prevent deferred_split_scan() touching ->_refcount */
2680 spin_lock(&ds_queue->split_queue_lock);
2681 count = page_count(head);
2682 mapcount = total_mapcount(head);
2683 if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) {
2684 if (!list_empty(page_deferred_list(head))) {
2685 ds_queue->split_queue_len--;
2686 list_del(page_deferred_list(head));
2688 spin_unlock(&ds_queue->split_queue_lock);
2690 if (PageSwapBacked(head))
2691 __dec_node_page_state(head, NR_SHMEM_THPS);
2693 __dec_node_page_state(head, NR_FILE_THPS);
2696 __split_huge_page(page, list, end, flags);
2697 if (PageSwapCache(head)) {
2698 swp_entry_t entry = { .val = page_private(head) };
2700 ret = split_swap_cluster(entry);
2704 if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
2705 pr_alert("total_mapcount: %u, page_count(): %u\n",
2708 dump_page(head, NULL);
2709 dump_page(page, "total_mapcount(head) > 0");
2712 spin_unlock(&ds_queue->split_queue_lock);
2714 xa_unlock(&mapping->i_pages);
2715 spin_unlock_irqrestore(&pgdata->lru_lock, flags);
2722 anon_vma_unlock_write(anon_vma);
2723 put_anon_vma(anon_vma);
2726 i_mmap_unlock_read(mapping);
2728 count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
2732 void free_transhuge_page(struct page *page)
2734 struct deferred_split *ds_queue = get_deferred_split_queue(page);
2735 unsigned long flags;
2737 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2738 if (!list_empty(page_deferred_list(page))) {
2739 ds_queue->split_queue_len--;
2740 list_del(page_deferred_list(page));
2742 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2743 free_compound_page(page);
2746 void deferred_split_huge_page(struct page *page)
2748 struct deferred_split *ds_queue = get_deferred_split_queue(page);
2750 struct mem_cgroup *memcg = compound_head(page)->mem_cgroup;
2752 unsigned long flags;
2754 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
2757 * The try_to_unmap() in page reclaim path might reach here too,
2758 * this may cause a race condition to corrupt deferred split queue.
2759 * And, if page reclaim is already handling the same page, it is
2760 * unnecessary to handle it again in shrinker.
2762 * Check PageSwapCache to determine if the page is being
2763 * handled by page reclaim since THP swap would add the page into
2764 * swap cache before calling try_to_unmap().
2766 if (PageSwapCache(page))
2769 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2770 if (list_empty(page_deferred_list(page))) {
2771 count_vm_event(THP_DEFERRED_SPLIT_PAGE);
2772 list_add_tail(page_deferred_list(page), &ds_queue->split_queue);
2773 ds_queue->split_queue_len++;
2776 memcg_set_shrinker_bit(memcg, page_to_nid(page),
2777 deferred_split_shrinker.id);
2780 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2783 static unsigned long deferred_split_count(struct shrinker *shrink,
2784 struct shrink_control *sc)
2786 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2787 struct deferred_split *ds_queue = &pgdata->deferred_split_queue;
2791 ds_queue = &sc->memcg->deferred_split_queue;
2793 return READ_ONCE(ds_queue->split_queue_len);
2796 static unsigned long deferred_split_scan(struct shrinker *shrink,
2797 struct shrink_control *sc)
2799 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2800 struct deferred_split *ds_queue = &pgdata->deferred_split_queue;
2801 unsigned long flags;
2802 LIST_HEAD(list), *pos, *next;
2808 ds_queue = &sc->memcg->deferred_split_queue;
2811 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2812 /* Take pin on all head pages to avoid freeing them under us */
2813 list_for_each_safe(pos, next, &ds_queue->split_queue) {
2814 page = list_entry((void *)pos, struct page, mapping);
2815 page = compound_head(page);
2816 if (get_page_unless_zero(page)) {
2817 list_move(page_deferred_list(page), &list);
2819 /* We lost race with put_compound_page() */
2820 list_del_init(page_deferred_list(page));
2821 ds_queue->split_queue_len--;
2823 if (!--sc->nr_to_scan)
2826 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2828 list_for_each_safe(pos, next, &list) {
2829 page = list_entry((void *)pos, struct page, mapping);
2830 if (!trylock_page(page))
2832 /* split_huge_page() removes page from list on success */
2833 if (!split_huge_page(page))
2840 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2841 list_splice_tail(&list, &ds_queue->split_queue);
2842 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2845 * Stop shrinker if we didn't split any page, but the queue is empty.
2846 * This can happen if pages were freed under us.
2848 if (!split && list_empty(&ds_queue->split_queue))
2853 static struct shrinker deferred_split_shrinker = {
2854 .count_objects = deferred_split_count,
2855 .scan_objects = deferred_split_scan,
2856 .seeks = DEFAULT_SEEKS,
2857 .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE |
2861 #ifdef CONFIG_DEBUG_FS
2862 static int split_huge_pages_set(void *data, u64 val)
2866 unsigned long pfn, max_zone_pfn;
2867 unsigned long total = 0, split = 0;
2872 for_each_populated_zone(zone) {
2873 max_zone_pfn = zone_end_pfn(zone);
2874 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
2875 if (!pfn_valid(pfn))
2878 page = pfn_to_page(pfn);
2879 if (!get_page_unless_zero(page))
2882 if (zone != page_zone(page))
2885 if (!PageHead(page) || PageHuge(page) || !PageLRU(page))
2890 if (!split_huge_page(page))
2898 pr_info("%lu of %lu THP split\n", split, total);
2902 DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set,
2905 static int __init split_huge_pages_debugfs(void)
2907 debugfs_create_file("split_huge_pages", 0200, NULL, NULL,
2908 &split_huge_pages_fops);
2911 late_initcall(split_huge_pages_debugfs);
2914 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
2915 void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
2918 struct vm_area_struct *vma = pvmw->vma;
2919 struct mm_struct *mm = vma->vm_mm;
2920 unsigned long address = pvmw->address;
2925 if (!(pvmw->pmd && !pvmw->pte))
2928 flush_cache_range(vma, address, address + HPAGE_PMD_SIZE);
2929 pmdval = pmdp_invalidate(vma, address, pvmw->pmd);
2930 if (pmd_dirty(pmdval))
2931 set_page_dirty(page);
2932 entry = make_migration_entry(page, pmd_write(pmdval));
2933 pmdswp = swp_entry_to_pmd(entry);
2934 if (pmd_soft_dirty(pmdval))
2935 pmdswp = pmd_swp_mksoft_dirty(pmdswp);
2936 set_pmd_at(mm, address, pvmw->pmd, pmdswp);
2937 page_remove_rmap(page, true);
2941 void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
2943 struct vm_area_struct *vma = pvmw->vma;
2944 struct mm_struct *mm = vma->vm_mm;
2945 unsigned long address = pvmw->address;
2946 unsigned long mmun_start = address & HPAGE_PMD_MASK;
2950 if (!(pvmw->pmd && !pvmw->pte))
2953 entry = pmd_to_swp_entry(*pvmw->pmd);
2955 pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot));
2956 if (pmd_swp_soft_dirty(*pvmw->pmd))
2957 pmde = pmd_mksoft_dirty(pmde);
2958 if (is_write_migration_entry(entry))
2959 pmde = maybe_pmd_mkwrite(pmde, vma);
2961 flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);
2963 page_add_anon_rmap(new, vma, mmun_start, true);
2965 page_add_file_rmap(new, true);
2966 set_pmd_at(mm, mmun_start, pvmw->pmd, pmde);
2967 if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new))
2968 mlock_vma_page(new);
2969 update_mmu_cache_pmd(vma, address, pvmw->pmd);