1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/sched/mm.h>
23 #include <linux/mmdebug.h>
24 #include <linux/sched/signal.h>
25 #include <linux/rmap.h>
26 #include <linux/string_helpers.h>
27 #include <linux/swap.h>
28 #include <linux/swapops.h>
29 #include <linux/jhash.h>
30 #include <linux/numa.h>
31 #include <linux/llist.h>
32 #include <linux/cma.h>
35 #include <asm/pgalloc.h>
39 #include <linux/hugetlb.h>
40 #include <linux/hugetlb_cgroup.h>
41 #include <linux/node.h>
42 #include <linux/page_owner.h>
45 int hugetlb_max_hstate __read_mostly;
46 unsigned int default_hstate_idx;
47 struct hstate hstates[HUGE_MAX_HSTATE];
50 static struct cma *hugetlb_cma[MAX_NUMNODES];
52 static unsigned long hugetlb_cma_size __initdata;
55 * Minimum page order among possible hugepage sizes, set to a proper value
58 static unsigned int minimum_order __read_mostly = UINT_MAX;
60 __initdata LIST_HEAD(huge_boot_pages);
62 /* for command line parsing */
63 static struct hstate * __initdata parsed_hstate;
64 static unsigned long __initdata default_hstate_max_huge_pages;
65 static bool __initdata parsed_valid_hugepagesz = true;
66 static bool __initdata parsed_default_hugepagesz;
69 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
70 * free_huge_pages, and surplus_huge_pages.
72 DEFINE_SPINLOCK(hugetlb_lock);
75 * Serializes faults on the same logical page. This is used to
76 * prevent spurious OOMs when the hugepage pool is fully utilized.
78 static int num_fault_mutexes;
79 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
81 /* Forward declaration */
82 static int hugetlb_acct_memory(struct hstate *h, long delta);
84 static inline bool subpool_is_free(struct hugepage_subpool *spool)
88 if (spool->max_hpages != -1)
89 return spool->used_hpages == 0;
90 if (spool->min_hpages != -1)
91 return spool->rsv_hpages == spool->min_hpages;
96 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
97 unsigned long irq_flags)
99 spin_unlock_irqrestore(&spool->lock, irq_flags);
101 /* If no pages are used, and no other handles to the subpool
102 * remain, give up any reservations based on minimum size and
103 * free the subpool */
104 if (subpool_is_free(spool)) {
105 if (spool->min_hpages != -1)
106 hugetlb_acct_memory(spool->hstate,
112 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
115 struct hugepage_subpool *spool;
117 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
121 spin_lock_init(&spool->lock);
123 spool->max_hpages = max_hpages;
125 spool->min_hpages = min_hpages;
127 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
131 spool->rsv_hpages = min_hpages;
136 void hugepage_put_subpool(struct hugepage_subpool *spool)
140 spin_lock_irqsave(&spool->lock, flags);
141 BUG_ON(!spool->count);
143 unlock_or_release_subpool(spool, flags);
147 * Subpool accounting for allocating and reserving pages.
148 * Return -ENOMEM if there are not enough resources to satisfy the
149 * request. Otherwise, return the number of pages by which the
150 * global pools must be adjusted (upward). The returned value may
151 * only be different than the passed value (delta) in the case where
152 * a subpool minimum size must be maintained.
154 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
162 spin_lock_irq(&spool->lock);
164 if (spool->max_hpages != -1) { /* maximum size accounting */
165 if ((spool->used_hpages + delta) <= spool->max_hpages)
166 spool->used_hpages += delta;
173 /* minimum size accounting */
174 if (spool->min_hpages != -1 && spool->rsv_hpages) {
175 if (delta > spool->rsv_hpages) {
177 * Asking for more reserves than those already taken on
178 * behalf of subpool. Return difference.
180 ret = delta - spool->rsv_hpages;
181 spool->rsv_hpages = 0;
183 ret = 0; /* reserves already accounted for */
184 spool->rsv_hpages -= delta;
189 spin_unlock_irq(&spool->lock);
194 * Subpool accounting for freeing and unreserving pages.
195 * Return the number of global page reservations that must be dropped.
196 * The return value may only be different than the passed value (delta)
197 * in the case where a subpool minimum size must be maintained.
199 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
208 spin_lock_irqsave(&spool->lock, flags);
210 if (spool->max_hpages != -1) /* maximum size accounting */
211 spool->used_hpages -= delta;
213 /* minimum size accounting */
214 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
215 if (spool->rsv_hpages + delta <= spool->min_hpages)
218 ret = spool->rsv_hpages + delta - spool->min_hpages;
220 spool->rsv_hpages += delta;
221 if (spool->rsv_hpages > spool->min_hpages)
222 spool->rsv_hpages = spool->min_hpages;
226 * If hugetlbfs_put_super couldn't free spool due to an outstanding
227 * quota reference, free it now.
229 unlock_or_release_subpool(spool, flags);
234 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
236 return HUGETLBFS_SB(inode->i_sb)->spool;
239 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
241 return subpool_inode(file_inode(vma->vm_file));
244 /* Helper that removes a struct file_region from the resv_map cache and returns
247 static struct file_region *
248 get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
250 struct file_region *nrg = NULL;
252 VM_BUG_ON(resv->region_cache_count <= 0);
254 resv->region_cache_count--;
255 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
256 list_del(&nrg->link);
264 static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
265 struct file_region *rg)
267 #ifdef CONFIG_CGROUP_HUGETLB
268 nrg->reservation_counter = rg->reservation_counter;
275 /* Helper that records hugetlb_cgroup uncharge info. */
276 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
278 struct resv_map *resv,
279 struct file_region *nrg)
281 #ifdef CONFIG_CGROUP_HUGETLB
283 nrg->reservation_counter =
284 &h_cg->rsvd_hugepage[hstate_index(h)];
285 nrg->css = &h_cg->css;
287 * The caller will hold exactly one h_cg->css reference for the
288 * whole contiguous reservation region. But this area might be
289 * scattered when there are already some file_regions reside in
290 * it. As a result, many file_regions may share only one css
291 * reference. In order to ensure that one file_region must hold
292 * exactly one h_cg->css reference, we should do css_get for
293 * each file_region and leave the reference held by caller
297 if (!resv->pages_per_hpage)
298 resv->pages_per_hpage = pages_per_huge_page(h);
299 /* pages_per_hpage should be the same for all entries in
302 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
304 nrg->reservation_counter = NULL;
310 static void put_uncharge_info(struct file_region *rg)
312 #ifdef CONFIG_CGROUP_HUGETLB
318 static bool has_same_uncharge_info(struct file_region *rg,
319 struct file_region *org)
321 #ifdef CONFIG_CGROUP_HUGETLB
323 rg->reservation_counter == org->reservation_counter &&
331 static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
333 struct file_region *nrg = NULL, *prg = NULL;
335 prg = list_prev_entry(rg, link);
336 if (&prg->link != &resv->regions && prg->to == rg->from &&
337 has_same_uncharge_info(prg, rg)) {
341 put_uncharge_info(rg);
347 nrg = list_next_entry(rg, link);
348 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
349 has_same_uncharge_info(nrg, rg)) {
350 nrg->from = rg->from;
353 put_uncharge_info(rg);
359 hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
360 long to, struct hstate *h, struct hugetlb_cgroup *cg,
361 long *regions_needed)
363 struct file_region *nrg;
365 if (!regions_needed) {
366 nrg = get_file_region_entry_from_cache(map, from, to);
367 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
368 list_add(&nrg->link, rg->link.prev);
369 coalesce_file_region(map, nrg);
371 *regions_needed += 1;
377 * Must be called with resv->lock held.
379 * Calling this with regions_needed != NULL will count the number of pages
380 * to be added but will not modify the linked list. And regions_needed will
381 * indicate the number of file_regions needed in the cache to carry out to add
382 * the regions for this range.
384 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
385 struct hugetlb_cgroup *h_cg,
386 struct hstate *h, long *regions_needed)
389 struct list_head *head = &resv->regions;
390 long last_accounted_offset = f;
391 struct file_region *rg = NULL, *trg = NULL;
396 /* In this loop, we essentially handle an entry for the range
397 * [last_accounted_offset, rg->from), at every iteration, with some
400 list_for_each_entry_safe(rg, trg, head, link) {
401 /* Skip irrelevant regions that start before our range. */
403 /* If this region ends after the last accounted offset,
404 * then we need to update last_accounted_offset.
406 if (rg->to > last_accounted_offset)
407 last_accounted_offset = rg->to;
411 /* When we find a region that starts beyond our range, we've
417 /* Add an entry for last_accounted_offset -> rg->from, and
418 * update last_accounted_offset.
420 if (rg->from > last_accounted_offset)
421 add += hugetlb_resv_map_add(resv, rg,
422 last_accounted_offset,
426 last_accounted_offset = rg->to;
429 /* Handle the case where our range extends beyond
430 * last_accounted_offset.
432 if (last_accounted_offset < t)
433 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
434 t, h, h_cg, regions_needed);
440 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
442 static int allocate_file_region_entries(struct resv_map *resv,
444 __must_hold(&resv->lock)
446 struct list_head allocated_regions;
447 int to_allocate = 0, i = 0;
448 struct file_region *trg = NULL, *rg = NULL;
450 VM_BUG_ON(regions_needed < 0);
452 INIT_LIST_HEAD(&allocated_regions);
455 * Check for sufficient descriptors in the cache to accommodate
456 * the number of in progress add operations plus regions_needed.
458 * This is a while loop because when we drop the lock, some other call
459 * to region_add or region_del may have consumed some region_entries,
460 * so we keep looping here until we finally have enough entries for
461 * (adds_in_progress + regions_needed).
463 while (resv->region_cache_count <
464 (resv->adds_in_progress + regions_needed)) {
465 to_allocate = resv->adds_in_progress + regions_needed -
466 resv->region_cache_count;
468 /* At this point, we should have enough entries in the cache
469 * for all the existing adds_in_progress. We should only be
470 * needing to allocate for regions_needed.
472 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
474 spin_unlock(&resv->lock);
475 for (i = 0; i < to_allocate; i++) {
476 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
479 list_add(&trg->link, &allocated_regions);
482 spin_lock(&resv->lock);
484 list_splice(&allocated_regions, &resv->region_cache);
485 resv->region_cache_count += to_allocate;
491 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
499 * Add the huge page range represented by [f, t) to the reserve
500 * map. Regions will be taken from the cache to fill in this range.
501 * Sufficient regions should exist in the cache due to the previous
502 * call to region_chg with the same range, but in some cases the cache will not
503 * have sufficient entries due to races with other code doing region_add or
504 * region_del. The extra needed entries will be allocated.
506 * regions_needed is the out value provided by a previous call to region_chg.
508 * Return the number of new huge pages added to the map. This number is greater
509 * than or equal to zero. If file_region entries needed to be allocated for
510 * this operation and we were not able to allocate, it returns -ENOMEM.
511 * region_add of regions of length 1 never allocate file_regions and cannot
512 * fail; region_chg will always allocate at least 1 entry and a region_add for
513 * 1 page will only require at most 1 entry.
515 static long region_add(struct resv_map *resv, long f, long t,
516 long in_regions_needed, struct hstate *h,
517 struct hugetlb_cgroup *h_cg)
519 long add = 0, actual_regions_needed = 0;
521 spin_lock(&resv->lock);
524 /* Count how many regions are actually needed to execute this add. */
525 add_reservation_in_range(resv, f, t, NULL, NULL,
526 &actual_regions_needed);
529 * Check for sufficient descriptors in the cache to accommodate
530 * this add operation. Note that actual_regions_needed may be greater
531 * than in_regions_needed, as the resv_map may have been modified since
532 * the region_chg call. In this case, we need to make sure that we
533 * allocate extra entries, such that we have enough for all the
534 * existing adds_in_progress, plus the excess needed for this
537 if (actual_regions_needed > in_regions_needed &&
538 resv->region_cache_count <
539 resv->adds_in_progress +
540 (actual_regions_needed - in_regions_needed)) {
541 /* region_add operation of range 1 should never need to
542 * allocate file_region entries.
544 VM_BUG_ON(t - f <= 1);
546 if (allocate_file_region_entries(
547 resv, actual_regions_needed - in_regions_needed)) {
554 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
556 resv->adds_in_progress -= in_regions_needed;
558 spin_unlock(&resv->lock);
563 * Examine the existing reserve map and determine how many
564 * huge pages in the specified range [f, t) are NOT currently
565 * represented. This routine is called before a subsequent
566 * call to region_add that will actually modify the reserve
567 * map to add the specified range [f, t). region_chg does
568 * not change the number of huge pages represented by the
569 * map. A number of new file_region structures is added to the cache as a
570 * placeholder, for the subsequent region_add call to use. At least 1
571 * file_region structure is added.
573 * out_regions_needed is the number of regions added to the
574 * resv->adds_in_progress. This value needs to be provided to a follow up call
575 * to region_add or region_abort for proper accounting.
577 * Returns the number of huge pages that need to be added to the existing
578 * reservation map for the range [f, t). This number is greater or equal to
579 * zero. -ENOMEM is returned if a new file_region structure or cache entry
580 * is needed and can not be allocated.
582 static long region_chg(struct resv_map *resv, long f, long t,
583 long *out_regions_needed)
587 spin_lock(&resv->lock);
589 /* Count how many hugepages in this range are NOT represented. */
590 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
593 if (*out_regions_needed == 0)
594 *out_regions_needed = 1;
596 if (allocate_file_region_entries(resv, *out_regions_needed))
599 resv->adds_in_progress += *out_regions_needed;
601 spin_unlock(&resv->lock);
606 * Abort the in progress add operation. The adds_in_progress field
607 * of the resv_map keeps track of the operations in progress between
608 * calls to region_chg and region_add. Operations are sometimes
609 * aborted after the call to region_chg. In such cases, region_abort
610 * is called to decrement the adds_in_progress counter. regions_needed
611 * is the value returned by the region_chg call, it is used to decrement
612 * the adds_in_progress counter.
614 * NOTE: The range arguments [f, t) are not needed or used in this
615 * routine. They are kept to make reading the calling code easier as
616 * arguments will match the associated region_chg call.
618 static void region_abort(struct resv_map *resv, long f, long t,
621 spin_lock(&resv->lock);
622 VM_BUG_ON(!resv->region_cache_count);
623 resv->adds_in_progress -= regions_needed;
624 spin_unlock(&resv->lock);
628 * Delete the specified range [f, t) from the reserve map. If the
629 * t parameter is LONG_MAX, this indicates that ALL regions after f
630 * should be deleted. Locate the regions which intersect [f, t)
631 * and either trim, delete or split the existing regions.
633 * Returns the number of huge pages deleted from the reserve map.
634 * In the normal case, the return value is zero or more. In the
635 * case where a region must be split, a new region descriptor must
636 * be allocated. If the allocation fails, -ENOMEM will be returned.
637 * NOTE: If the parameter t == LONG_MAX, then we will never split
638 * a region and possibly return -ENOMEM. Callers specifying
639 * t == LONG_MAX do not need to check for -ENOMEM error.
641 static long region_del(struct resv_map *resv, long f, long t)
643 struct list_head *head = &resv->regions;
644 struct file_region *rg, *trg;
645 struct file_region *nrg = NULL;
649 spin_lock(&resv->lock);
650 list_for_each_entry_safe(rg, trg, head, link) {
652 * Skip regions before the range to be deleted. file_region
653 * ranges are normally of the form [from, to). However, there
654 * may be a "placeholder" entry in the map which is of the form
655 * (from, to) with from == to. Check for placeholder entries
656 * at the beginning of the range to be deleted.
658 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
664 if (f > rg->from && t < rg->to) { /* Must split region */
666 * Check for an entry in the cache before dropping
667 * lock and attempting allocation.
670 resv->region_cache_count > resv->adds_in_progress) {
671 nrg = list_first_entry(&resv->region_cache,
674 list_del(&nrg->link);
675 resv->region_cache_count--;
679 spin_unlock(&resv->lock);
680 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
687 hugetlb_cgroup_uncharge_file_region(
688 resv, rg, t - f, false);
690 /* New entry for end of split region */
694 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
696 INIT_LIST_HEAD(&nrg->link);
698 /* Original entry is trimmed */
701 list_add(&nrg->link, &rg->link);
706 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
707 del += rg->to - rg->from;
708 hugetlb_cgroup_uncharge_file_region(resv, rg,
709 rg->to - rg->from, true);
715 if (f <= rg->from) { /* Trim beginning of region */
716 hugetlb_cgroup_uncharge_file_region(resv, rg,
717 t - rg->from, false);
721 } else { /* Trim end of region */
722 hugetlb_cgroup_uncharge_file_region(resv, rg,
730 spin_unlock(&resv->lock);
736 * A rare out of memory error was encountered which prevented removal of
737 * the reserve map region for a page. The huge page itself was free'ed
738 * and removed from the page cache. This routine will adjust the subpool
739 * usage count, and the global reserve count if needed. By incrementing
740 * these counts, the reserve map entry which could not be deleted will
741 * appear as a "reserved" entry instead of simply dangling with incorrect
744 void hugetlb_fix_reserve_counts(struct inode *inode)
746 struct hugepage_subpool *spool = subpool_inode(inode);
748 bool reserved = false;
750 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
751 if (rsv_adjust > 0) {
752 struct hstate *h = hstate_inode(inode);
754 if (!hugetlb_acct_memory(h, 1))
756 } else if (!rsv_adjust) {
761 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
765 * Count and return the number of huge pages in the reserve map
766 * that intersect with the range [f, t).
768 static long region_count(struct resv_map *resv, long f, long t)
770 struct list_head *head = &resv->regions;
771 struct file_region *rg;
774 spin_lock(&resv->lock);
775 /* Locate each segment we overlap with, and count that overlap. */
776 list_for_each_entry(rg, head, link) {
785 seg_from = max(rg->from, f);
786 seg_to = min(rg->to, t);
788 chg += seg_to - seg_from;
790 spin_unlock(&resv->lock);
796 * Convert the address within this vma to the page offset within
797 * the mapping, in pagecache page units; huge pages here.
799 static pgoff_t vma_hugecache_offset(struct hstate *h,
800 struct vm_area_struct *vma, unsigned long address)
802 return ((address - vma->vm_start) >> huge_page_shift(h)) +
803 (vma->vm_pgoff >> huge_page_order(h));
806 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
807 unsigned long address)
809 return vma_hugecache_offset(hstate_vma(vma), vma, address);
811 EXPORT_SYMBOL_GPL(linear_hugepage_index);
814 * Return the size of the pages allocated when backing a VMA. In the majority
815 * cases this will be same size as used by the page table entries.
817 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
819 if (vma->vm_ops && vma->vm_ops->pagesize)
820 return vma->vm_ops->pagesize(vma);
823 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
826 * Return the page size being used by the MMU to back a VMA. In the majority
827 * of cases, the page size used by the kernel matches the MMU size. On
828 * architectures where it differs, an architecture-specific 'strong'
829 * version of this symbol is required.
831 __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
833 return vma_kernel_pagesize(vma);
837 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
838 * bits of the reservation map pointer, which are always clear due to
841 #define HPAGE_RESV_OWNER (1UL << 0)
842 #define HPAGE_RESV_UNMAPPED (1UL << 1)
843 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
846 * These helpers are used to track how many pages are reserved for
847 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
848 * is guaranteed to have their future faults succeed.
850 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
851 * the reserve counters are updated with the hugetlb_lock held. It is safe
852 * to reset the VMA at fork() time as it is not in use yet and there is no
853 * chance of the global counters getting corrupted as a result of the values.
855 * The private mapping reservation is represented in a subtly different
856 * manner to a shared mapping. A shared mapping has a region map associated
857 * with the underlying file, this region map represents the backing file
858 * pages which have ever had a reservation assigned which this persists even
859 * after the page is instantiated. A private mapping has a region map
860 * associated with the original mmap which is attached to all VMAs which
861 * reference it, this region map represents those offsets which have consumed
862 * reservation ie. where pages have been instantiated.
864 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
866 return (unsigned long)vma->vm_private_data;
869 static void set_vma_private_data(struct vm_area_struct *vma,
872 vma->vm_private_data = (void *)value;
876 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
877 struct hugetlb_cgroup *h_cg,
880 #ifdef CONFIG_CGROUP_HUGETLB
882 resv_map->reservation_counter = NULL;
883 resv_map->pages_per_hpage = 0;
884 resv_map->css = NULL;
886 resv_map->reservation_counter =
887 &h_cg->rsvd_hugepage[hstate_index(h)];
888 resv_map->pages_per_hpage = pages_per_huge_page(h);
889 resv_map->css = &h_cg->css;
894 struct resv_map *resv_map_alloc(void)
896 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
897 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
899 if (!resv_map || !rg) {
905 kref_init(&resv_map->refs);
906 spin_lock_init(&resv_map->lock);
907 INIT_LIST_HEAD(&resv_map->regions);
909 resv_map->adds_in_progress = 0;
911 * Initialize these to 0. On shared mappings, 0's here indicate these
912 * fields don't do cgroup accounting. On private mappings, these will be
913 * re-initialized to the proper values, to indicate that hugetlb cgroup
914 * reservations are to be un-charged from here.
916 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
918 INIT_LIST_HEAD(&resv_map->region_cache);
919 list_add(&rg->link, &resv_map->region_cache);
920 resv_map->region_cache_count = 1;
925 void resv_map_release(struct kref *ref)
927 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
928 struct list_head *head = &resv_map->region_cache;
929 struct file_region *rg, *trg;
931 /* Clear out any active regions before we release the map. */
932 region_del(resv_map, 0, LONG_MAX);
934 /* ... and any entries left in the cache */
935 list_for_each_entry_safe(rg, trg, head, link) {
940 VM_BUG_ON(resv_map->adds_in_progress);
945 static inline struct resv_map *inode_resv_map(struct inode *inode)
948 * At inode evict time, i_mapping may not point to the original
949 * address space within the inode. This original address space
950 * contains the pointer to the resv_map. So, always use the
951 * address space embedded within the inode.
952 * The VERY common case is inode->mapping == &inode->i_data but,
953 * this may not be true for device special inodes.
955 return (struct resv_map *)(&inode->i_data)->private_data;
958 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
960 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
961 if (vma->vm_flags & VM_MAYSHARE) {
962 struct address_space *mapping = vma->vm_file->f_mapping;
963 struct inode *inode = mapping->host;
965 return inode_resv_map(inode);
968 return (struct resv_map *)(get_vma_private_data(vma) &
973 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
975 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
976 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
978 set_vma_private_data(vma, (get_vma_private_data(vma) &
979 HPAGE_RESV_MASK) | (unsigned long)map);
982 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
984 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
985 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
987 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
990 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
992 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
994 return (get_vma_private_data(vma) & flag) != 0;
997 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
998 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
1000 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1001 if (!(vma->vm_flags & VM_MAYSHARE))
1002 vma->vm_private_data = (void *)0;
1005 /* Returns true if the VMA has associated reserve pages */
1006 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1008 if (vma->vm_flags & VM_NORESERVE) {
1010 * This address is already reserved by other process(chg == 0),
1011 * so, we should decrement reserved count. Without decrementing,
1012 * reserve count remains after releasing inode, because this
1013 * allocated page will go into page cache and is regarded as
1014 * coming from reserved pool in releasing step. Currently, we
1015 * don't have any other solution to deal with this situation
1016 * properly, so add work-around here.
1018 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1024 /* Shared mappings always use reserves */
1025 if (vma->vm_flags & VM_MAYSHARE) {
1027 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1028 * be a region map for all pages. The only situation where
1029 * there is no region map is if a hole was punched via
1030 * fallocate. In this case, there really are no reserves to
1031 * use. This situation is indicated if chg != 0.
1040 * Only the process that called mmap() has reserves for
1043 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1045 * Like the shared case above, a hole punch or truncate
1046 * could have been performed on the private mapping.
1047 * Examine the value of chg to determine if reserves
1048 * actually exist or were previously consumed.
1049 * Very Subtle - The value of chg comes from a previous
1050 * call to vma_needs_reserves(). The reserve map for
1051 * private mappings has different (opposite) semantics
1052 * than that of shared mappings. vma_needs_reserves()
1053 * has already taken this difference in semantics into
1054 * account. Therefore, the meaning of chg is the same
1055 * as in the shared case above. Code could easily be
1056 * combined, but keeping it separate draws attention to
1057 * subtle differences.
1068 static void enqueue_huge_page(struct hstate *h, struct page *page)
1070 int nid = page_to_nid(page);
1072 lockdep_assert_held(&hugetlb_lock);
1073 list_move(&page->lru, &h->hugepage_freelists[nid]);
1074 h->free_huge_pages++;
1075 h->free_huge_pages_node[nid]++;
1076 SetHPageFreed(page);
1079 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1082 bool pin = !!(current->flags & PF_MEMALLOC_PIN);
1084 lockdep_assert_held(&hugetlb_lock);
1085 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1086 if (pin && !is_pinnable_page(page))
1089 if (PageHWPoison(page))
1092 list_move(&page->lru, &h->hugepage_activelist);
1093 set_page_refcounted(page);
1094 ClearHPageFreed(page);
1095 h->free_huge_pages--;
1096 h->free_huge_pages_node[nid]--;
1103 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1106 unsigned int cpuset_mems_cookie;
1107 struct zonelist *zonelist;
1110 int node = NUMA_NO_NODE;
1112 zonelist = node_zonelist(nid, gfp_mask);
1115 cpuset_mems_cookie = read_mems_allowed_begin();
1116 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1119 if (!cpuset_zone_allowed(zone, gfp_mask))
1122 * no need to ask again on the same node. Pool is node rather than
1125 if (zone_to_nid(zone) == node)
1127 node = zone_to_nid(zone);
1129 page = dequeue_huge_page_node_exact(h, node);
1133 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1139 static struct page *dequeue_huge_page_vma(struct hstate *h,
1140 struct vm_area_struct *vma,
1141 unsigned long address, int avoid_reserve,
1145 struct mempolicy *mpol;
1147 nodemask_t *nodemask;
1151 * A child process with MAP_PRIVATE mappings created by their parent
1152 * have no page reserves. This check ensures that reservations are
1153 * not "stolen". The child may still get SIGKILLed
1155 if (!vma_has_reserves(vma, chg) &&
1156 h->free_huge_pages - h->resv_huge_pages == 0)
1159 /* If reserves cannot be used, ensure enough pages are in the pool */
1160 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1163 gfp_mask = htlb_alloc_mask(h);
1164 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1165 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1166 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1167 SetHPageRestoreReserve(page);
1168 h->resv_huge_pages--;
1171 mpol_cond_put(mpol);
1179 * common helper functions for hstate_next_node_to_{alloc|free}.
1180 * We may have allocated or freed a huge page based on a different
1181 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1182 * be outside of *nodes_allowed. Ensure that we use an allowed
1183 * node for alloc or free.
1185 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1187 nid = next_node_in(nid, *nodes_allowed);
1188 VM_BUG_ON(nid >= MAX_NUMNODES);
1193 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1195 if (!node_isset(nid, *nodes_allowed))
1196 nid = next_node_allowed(nid, nodes_allowed);
1201 * returns the previously saved node ["this node"] from which to
1202 * allocate a persistent huge page for the pool and advance the
1203 * next node from which to allocate, handling wrap at end of node
1206 static int hstate_next_node_to_alloc(struct hstate *h,
1207 nodemask_t *nodes_allowed)
1211 VM_BUG_ON(!nodes_allowed);
1213 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1214 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1220 * helper for remove_pool_huge_page() - return the previously saved
1221 * node ["this node"] from which to free a huge page. Advance the
1222 * next node id whether or not we find a free huge page to free so
1223 * that the next attempt to free addresses the next node.
1225 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1229 VM_BUG_ON(!nodes_allowed);
1231 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1232 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1237 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1238 for (nr_nodes = nodes_weight(*mask); \
1240 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1243 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1244 for (nr_nodes = nodes_weight(*mask); \
1246 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1249 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1250 static void destroy_compound_gigantic_page(struct page *page,
1254 int nr_pages = 1 << order;
1255 struct page *p = page + 1;
1257 atomic_set(compound_mapcount_ptr(page), 0);
1258 atomic_set(compound_pincount_ptr(page), 0);
1260 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1261 clear_compound_head(p);
1262 set_page_refcounted(p);
1265 set_compound_order(page, 0);
1266 page[1].compound_nr = 0;
1267 __ClearPageHead(page);
1270 static void free_gigantic_page(struct page *page, unsigned int order)
1273 * If the page isn't allocated using the cma allocator,
1274 * cma_release() returns false.
1277 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1281 free_contig_range(page_to_pfn(page), 1 << order);
1284 #ifdef CONFIG_CONTIG_ALLOC
1285 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1286 int nid, nodemask_t *nodemask)
1288 unsigned long nr_pages = pages_per_huge_page(h);
1289 if (nid == NUMA_NO_NODE)
1290 nid = numa_mem_id();
1297 if (hugetlb_cma[nid]) {
1298 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1299 huge_page_order(h), true);
1304 if (!(gfp_mask & __GFP_THISNODE)) {
1305 for_each_node_mask(node, *nodemask) {
1306 if (node == nid || !hugetlb_cma[node])
1309 page = cma_alloc(hugetlb_cma[node], nr_pages,
1310 huge_page_order(h), true);
1318 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1321 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1322 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1323 #else /* !CONFIG_CONTIG_ALLOC */
1324 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1325 int nid, nodemask_t *nodemask)
1329 #endif /* CONFIG_CONTIG_ALLOC */
1331 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1332 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1333 int nid, nodemask_t *nodemask)
1337 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1338 static inline void destroy_compound_gigantic_page(struct page *page,
1339 unsigned int order) { }
1343 * Remove hugetlb page from lists, and update dtor so that page appears
1344 * as just a compound page. A reference is held on the page.
1346 * Must be called with hugetlb lock held.
1348 static void remove_hugetlb_page(struct hstate *h, struct page *page,
1349 bool adjust_surplus)
1351 int nid = page_to_nid(page);
1353 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1354 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1356 lockdep_assert_held(&hugetlb_lock);
1357 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1360 list_del(&page->lru);
1362 if (HPageFreed(page)) {
1363 h->free_huge_pages--;
1364 h->free_huge_pages_node[nid]--;
1366 if (adjust_surplus) {
1367 h->surplus_huge_pages--;
1368 h->surplus_huge_pages_node[nid]--;
1371 set_page_refcounted(page);
1372 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1375 h->nr_huge_pages_node[nid]--;
1378 static void update_and_free_page(struct hstate *h, struct page *page)
1381 struct page *subpage = page;
1383 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1386 for (i = 0; i < pages_per_huge_page(h);
1387 i++, subpage = mem_map_next(subpage, page, i)) {
1388 subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1389 1 << PG_referenced | 1 << PG_dirty |
1390 1 << PG_active | 1 << PG_private |
1393 if (hstate_is_gigantic(h)) {
1394 destroy_compound_gigantic_page(page, huge_page_order(h));
1395 free_gigantic_page(page, huge_page_order(h));
1397 __free_pages(page, huge_page_order(h));
1401 static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
1403 struct page *page, *t_page;
1405 list_for_each_entry_safe(page, t_page, list, lru) {
1406 update_and_free_page(h, page);
1411 struct hstate *size_to_hstate(unsigned long size)
1415 for_each_hstate(h) {
1416 if (huge_page_size(h) == size)
1422 void free_huge_page(struct page *page)
1425 * Can't pass hstate in here because it is called from the
1426 * compound page destructor.
1428 struct hstate *h = page_hstate(page);
1429 int nid = page_to_nid(page);
1430 struct hugepage_subpool *spool = hugetlb_page_subpool(page);
1431 bool restore_reserve;
1432 unsigned long flags;
1434 VM_BUG_ON_PAGE(page_count(page), page);
1435 VM_BUG_ON_PAGE(page_mapcount(page), page);
1437 hugetlb_set_page_subpool(page, NULL);
1438 page->mapping = NULL;
1439 restore_reserve = HPageRestoreReserve(page);
1440 ClearHPageRestoreReserve(page);
1443 * If HPageRestoreReserve was set on page, page allocation consumed a
1444 * reservation. If the page was associated with a subpool, there
1445 * would have been a page reserved in the subpool before allocation
1446 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1447 * reservation, do not call hugepage_subpool_put_pages() as this will
1448 * remove the reserved page from the subpool.
1450 if (!restore_reserve) {
1452 * A return code of zero implies that the subpool will be
1453 * under its minimum size if the reservation is not restored
1454 * after page is free. Therefore, force restore_reserve
1457 if (hugepage_subpool_put_pages(spool, 1) == 0)
1458 restore_reserve = true;
1461 spin_lock_irqsave(&hugetlb_lock, flags);
1462 ClearHPageMigratable(page);
1463 hugetlb_cgroup_uncharge_page(hstate_index(h),
1464 pages_per_huge_page(h), page);
1465 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1466 pages_per_huge_page(h), page);
1467 if (restore_reserve)
1468 h->resv_huge_pages++;
1470 if (HPageTemporary(page)) {
1471 remove_hugetlb_page(h, page, false);
1472 spin_unlock_irqrestore(&hugetlb_lock, flags);
1473 update_and_free_page(h, page);
1474 } else if (h->surplus_huge_pages_node[nid]) {
1475 /* remove the page from active list */
1476 remove_hugetlb_page(h, page, true);
1477 spin_unlock_irqrestore(&hugetlb_lock, flags);
1478 update_and_free_page(h, page);
1480 arch_clear_hugepage_flags(page);
1481 enqueue_huge_page(h, page);
1482 spin_unlock_irqrestore(&hugetlb_lock, flags);
1487 * Must be called with the hugetlb lock held
1489 static void __prep_account_new_huge_page(struct hstate *h, int nid)
1491 lockdep_assert_held(&hugetlb_lock);
1493 h->nr_huge_pages_node[nid]++;
1496 static void __prep_new_huge_page(struct page *page)
1498 INIT_LIST_HEAD(&page->lru);
1499 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1500 hugetlb_set_page_subpool(page, NULL);
1501 set_hugetlb_cgroup(page, NULL);
1502 set_hugetlb_cgroup_rsvd(page, NULL);
1505 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1507 __prep_new_huge_page(page);
1508 spin_lock_irq(&hugetlb_lock);
1509 __prep_account_new_huge_page(h, nid);
1510 spin_unlock_irq(&hugetlb_lock);
1513 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1516 int nr_pages = 1 << order;
1517 struct page *p = page + 1;
1519 /* we rely on prep_new_huge_page to set the destructor */
1520 set_compound_order(page, order);
1521 __ClearPageReserved(page);
1522 __SetPageHead(page);
1523 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1525 * For gigantic hugepages allocated through bootmem at
1526 * boot, it's safer to be consistent with the not-gigantic
1527 * hugepages and clear the PG_reserved bit from all tail pages
1528 * too. Otherwise drivers using get_user_pages() to access tail
1529 * pages may get the reference counting wrong if they see
1530 * PG_reserved set on a tail page (despite the head page not
1531 * having PG_reserved set). Enforcing this consistency between
1532 * head and tail pages allows drivers to optimize away a check
1533 * on the head page when they need know if put_page() is needed
1534 * after get_user_pages().
1536 __ClearPageReserved(p);
1537 set_page_count(p, 0);
1538 set_compound_head(p, page);
1540 atomic_set(compound_mapcount_ptr(page), -1);
1541 atomic_set(compound_pincount_ptr(page), 0);
1545 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1546 * transparent huge pages. See the PageTransHuge() documentation for more
1549 int PageHuge(struct page *page)
1551 if (!PageCompound(page))
1554 page = compound_head(page);
1555 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1557 EXPORT_SYMBOL_GPL(PageHuge);
1560 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1561 * normal or transparent huge pages.
1563 int PageHeadHuge(struct page *page_head)
1565 if (!PageHead(page_head))
1568 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1572 * Find and lock address space (mapping) in write mode.
1574 * Upon entry, the page is locked which means that page_mapping() is
1575 * stable. Due to locking order, we can only trylock_write. If we can
1576 * not get the lock, simply return NULL to caller.
1578 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1580 struct address_space *mapping = page_mapping(hpage);
1585 if (i_mmap_trylock_write(mapping))
1591 pgoff_t hugetlb_basepage_index(struct page *page)
1593 struct page *page_head = compound_head(page);
1594 pgoff_t index = page_index(page_head);
1595 unsigned long compound_idx;
1597 if (compound_order(page_head) >= MAX_ORDER)
1598 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1600 compound_idx = page - page_head;
1602 return (index << compound_order(page_head)) + compound_idx;
1605 static struct page *alloc_buddy_huge_page(struct hstate *h,
1606 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1607 nodemask_t *node_alloc_noretry)
1609 int order = huge_page_order(h);
1611 bool alloc_try_hard = true;
1614 * By default we always try hard to allocate the page with
1615 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1616 * a loop (to adjust global huge page counts) and previous allocation
1617 * failed, do not continue to try hard on the same node. Use the
1618 * node_alloc_noretry bitmap to manage this state information.
1620 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1621 alloc_try_hard = false;
1622 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1624 gfp_mask |= __GFP_RETRY_MAYFAIL;
1625 if (nid == NUMA_NO_NODE)
1626 nid = numa_mem_id();
1627 page = __alloc_pages(gfp_mask, order, nid, nmask);
1629 __count_vm_event(HTLB_BUDDY_PGALLOC);
1631 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1634 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1635 * indicates an overall state change. Clear bit so that we resume
1636 * normal 'try hard' allocations.
1638 if (node_alloc_noretry && page && !alloc_try_hard)
1639 node_clear(nid, *node_alloc_noretry);
1642 * If we tried hard to get a page but failed, set bit so that
1643 * subsequent attempts will not try as hard until there is an
1644 * overall state change.
1646 if (node_alloc_noretry && !page && alloc_try_hard)
1647 node_set(nid, *node_alloc_noretry);
1653 * Common helper to allocate a fresh hugetlb page. All specific allocators
1654 * should use this function to get new hugetlb pages
1656 static struct page *alloc_fresh_huge_page(struct hstate *h,
1657 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1658 nodemask_t *node_alloc_noretry)
1662 if (hstate_is_gigantic(h))
1663 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1665 page = alloc_buddy_huge_page(h, gfp_mask,
1666 nid, nmask, node_alloc_noretry);
1670 if (hstate_is_gigantic(h))
1671 prep_compound_gigantic_page(page, huge_page_order(h));
1672 prep_new_huge_page(h, page, page_to_nid(page));
1678 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1681 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1682 nodemask_t *node_alloc_noretry)
1686 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1688 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1689 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1690 node_alloc_noretry);
1698 put_page(page); /* free it into the hugepage allocator */
1704 * Remove huge page from pool from next node to free. Attempt to keep
1705 * persistent huge pages more or less balanced over allowed nodes.
1706 * This routine only 'removes' the hugetlb page. The caller must make
1707 * an additional call to free the page to low level allocators.
1708 * Called with hugetlb_lock locked.
1710 static struct page *remove_pool_huge_page(struct hstate *h,
1711 nodemask_t *nodes_allowed,
1715 struct page *page = NULL;
1717 lockdep_assert_held(&hugetlb_lock);
1718 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1720 * If we're returning unused surplus pages, only examine
1721 * nodes with surplus pages.
1723 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1724 !list_empty(&h->hugepage_freelists[node])) {
1725 page = list_entry(h->hugepage_freelists[node].next,
1727 remove_hugetlb_page(h, page, acct_surplus);
1736 * Dissolve a given free hugepage into free buddy pages. This function does
1737 * nothing for in-use hugepages and non-hugepages.
1738 * This function returns values like below:
1740 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1741 * (allocated or reserved.)
1742 * 0: successfully dissolved free hugepages or the page is not a
1743 * hugepage (considered as already dissolved)
1745 int dissolve_free_huge_page(struct page *page)
1750 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1751 if (!PageHuge(page))
1754 spin_lock_irq(&hugetlb_lock);
1755 if (!PageHuge(page)) {
1760 if (!page_count(page)) {
1761 struct page *head = compound_head(page);
1762 struct hstate *h = page_hstate(head);
1763 if (h->free_huge_pages - h->resv_huge_pages == 0)
1767 * We should make sure that the page is already on the free list
1768 * when it is dissolved.
1770 if (unlikely(!HPageFreed(head))) {
1771 spin_unlock_irq(&hugetlb_lock);
1775 * Theoretically, we should return -EBUSY when we
1776 * encounter this race. In fact, we have a chance
1777 * to successfully dissolve the page if we do a
1778 * retry. Because the race window is quite small.
1779 * If we seize this opportunity, it is an optimization
1780 * for increasing the success rate of dissolving page.
1786 * Move PageHWPoison flag from head page to the raw error page,
1787 * which makes any subpages rather than the error page reusable.
1789 if (PageHWPoison(head) && page != head) {
1790 SetPageHWPoison(page);
1791 ClearPageHWPoison(head);
1793 remove_hugetlb_page(h, head, false);
1794 h->max_huge_pages--;
1795 spin_unlock_irq(&hugetlb_lock);
1796 update_and_free_page(h, head);
1800 spin_unlock_irq(&hugetlb_lock);
1805 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1806 * make specified memory blocks removable from the system.
1807 * Note that this will dissolve a free gigantic hugepage completely, if any
1808 * part of it lies within the given range.
1809 * Also note that if dissolve_free_huge_page() returns with an error, all
1810 * free hugepages that were dissolved before that error are lost.
1812 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1818 if (!hugepages_supported())
1821 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1822 page = pfn_to_page(pfn);
1823 rc = dissolve_free_huge_page(page);
1832 * Allocates a fresh surplus page from the page allocator.
1834 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1835 int nid, nodemask_t *nmask)
1837 struct page *page = NULL;
1839 if (hstate_is_gigantic(h))
1842 spin_lock_irq(&hugetlb_lock);
1843 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1845 spin_unlock_irq(&hugetlb_lock);
1847 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1851 spin_lock_irq(&hugetlb_lock);
1853 * We could have raced with the pool size change.
1854 * Double check that and simply deallocate the new page
1855 * if we would end up overcommiting the surpluses. Abuse
1856 * temporary page to workaround the nasty free_huge_page
1859 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1860 SetHPageTemporary(page);
1861 spin_unlock_irq(&hugetlb_lock);
1865 h->surplus_huge_pages++;
1866 h->surplus_huge_pages_node[page_to_nid(page)]++;
1870 spin_unlock_irq(&hugetlb_lock);
1875 static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1876 int nid, nodemask_t *nmask)
1880 if (hstate_is_gigantic(h))
1883 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1888 * We do not account these pages as surplus because they are only
1889 * temporary and will be released properly on the last reference
1891 SetHPageTemporary(page);
1897 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1900 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1901 struct vm_area_struct *vma, unsigned long addr)
1904 struct mempolicy *mpol;
1905 gfp_t gfp_mask = htlb_alloc_mask(h);
1907 nodemask_t *nodemask;
1909 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1910 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1911 mpol_cond_put(mpol);
1916 /* page migration callback function */
1917 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1918 nodemask_t *nmask, gfp_t gfp_mask)
1920 spin_lock_irq(&hugetlb_lock);
1921 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1924 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1926 spin_unlock_irq(&hugetlb_lock);
1930 spin_unlock_irq(&hugetlb_lock);
1932 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1935 /* mempolicy aware migration callback */
1936 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
1937 unsigned long address)
1939 struct mempolicy *mpol;
1940 nodemask_t *nodemask;
1945 gfp_mask = htlb_alloc_mask(h);
1946 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1947 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
1948 mpol_cond_put(mpol);
1954 * Increase the hugetlb pool such that it can accommodate a reservation
1957 static int gather_surplus_pages(struct hstate *h, long delta)
1958 __must_hold(&hugetlb_lock)
1960 struct list_head surplus_list;
1961 struct page *page, *tmp;
1964 long needed, allocated;
1965 bool alloc_ok = true;
1967 lockdep_assert_held(&hugetlb_lock);
1968 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1970 h->resv_huge_pages += delta;
1975 INIT_LIST_HEAD(&surplus_list);
1979 spin_unlock_irq(&hugetlb_lock);
1980 for (i = 0; i < needed; i++) {
1981 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1982 NUMA_NO_NODE, NULL);
1987 list_add(&page->lru, &surplus_list);
1993 * After retaking hugetlb_lock, we need to recalculate 'needed'
1994 * because either resv_huge_pages or free_huge_pages may have changed.
1996 spin_lock_irq(&hugetlb_lock);
1997 needed = (h->resv_huge_pages + delta) -
1998 (h->free_huge_pages + allocated);
2003 * We were not able to allocate enough pages to
2004 * satisfy the entire reservation so we free what
2005 * we've allocated so far.
2010 * The surplus_list now contains _at_least_ the number of extra pages
2011 * needed to accommodate the reservation. Add the appropriate number
2012 * of pages to the hugetlb pool and free the extras back to the buddy
2013 * allocator. Commit the entire reservation here to prevent another
2014 * process from stealing the pages as they are added to the pool but
2015 * before they are reserved.
2017 needed += allocated;
2018 h->resv_huge_pages += delta;
2021 /* Free the needed pages to the hugetlb pool */
2022 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2028 * This page is now managed by the hugetlb allocator and has
2029 * no users -- drop the buddy allocator's reference.
2031 zeroed = put_page_testzero(page);
2032 VM_BUG_ON_PAGE(!zeroed, page);
2033 enqueue_huge_page(h, page);
2036 spin_unlock_irq(&hugetlb_lock);
2038 /* Free unnecessary surplus pages to the buddy allocator */
2039 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2041 spin_lock_irq(&hugetlb_lock);
2047 * This routine has two main purposes:
2048 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2049 * in unused_resv_pages. This corresponds to the prior adjustments made
2050 * to the associated reservation map.
2051 * 2) Free any unused surplus pages that may have been allocated to satisfy
2052 * the reservation. As many as unused_resv_pages may be freed.
2054 static void return_unused_surplus_pages(struct hstate *h,
2055 unsigned long unused_resv_pages)
2057 unsigned long nr_pages;
2059 LIST_HEAD(page_list);
2061 lockdep_assert_held(&hugetlb_lock);
2062 /* Uncommit the reservation */
2063 h->resv_huge_pages -= unused_resv_pages;
2065 /* Cannot return gigantic pages currently */
2066 if (hstate_is_gigantic(h))
2070 * Part (or even all) of the reservation could have been backed
2071 * by pre-allocated pages. Only free surplus pages.
2073 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2076 * We want to release as many surplus pages as possible, spread
2077 * evenly across all nodes with memory. Iterate across these nodes
2078 * until we can no longer free unreserved surplus pages. This occurs
2079 * when the nodes with surplus pages have no free pages.
2080 * remove_pool_huge_page() will balance the freed pages across the
2081 * on-line nodes with memory and will handle the hstate accounting.
2083 while (nr_pages--) {
2084 page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1);
2088 list_add(&page->lru, &page_list);
2092 spin_unlock_irq(&hugetlb_lock);
2093 update_and_free_pages_bulk(h, &page_list);
2094 spin_lock_irq(&hugetlb_lock);
2099 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2100 * are used by the huge page allocation routines to manage reservations.
2102 * vma_needs_reservation is called to determine if the huge page at addr
2103 * within the vma has an associated reservation. If a reservation is
2104 * needed, the value 1 is returned. The caller is then responsible for
2105 * managing the global reservation and subpool usage counts. After
2106 * the huge page has been allocated, vma_commit_reservation is called
2107 * to add the page to the reservation map. If the page allocation fails,
2108 * the reservation must be ended instead of committed. vma_end_reservation
2109 * is called in such cases.
2111 * In the normal case, vma_commit_reservation returns the same value
2112 * as the preceding vma_needs_reservation call. The only time this
2113 * is not the case is if a reserve map was changed between calls. It
2114 * is the responsibility of the caller to notice the difference and
2115 * take appropriate action.
2117 * vma_add_reservation is used in error paths where a reservation must
2118 * be restored when a newly allocated huge page must be freed. It is
2119 * to be called after calling vma_needs_reservation to determine if a
2120 * reservation exists.
2122 * vma_del_reservation is used in error paths where an entry in the reserve
2123 * map was created during huge page allocation and must be removed. It is to
2124 * be called after calling vma_needs_reservation to determine if a reservation
2127 enum vma_resv_mode {
2134 static long __vma_reservation_common(struct hstate *h,
2135 struct vm_area_struct *vma, unsigned long addr,
2136 enum vma_resv_mode mode)
2138 struct resv_map *resv;
2141 long dummy_out_regions_needed;
2143 resv = vma_resv_map(vma);
2147 idx = vma_hugecache_offset(h, vma, addr);
2149 case VMA_NEEDS_RESV:
2150 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2151 /* We assume that vma_reservation_* routines always operate on
2152 * 1 page, and that adding to resv map a 1 page entry can only
2153 * ever require 1 region.
2155 VM_BUG_ON(dummy_out_regions_needed != 1);
2157 case VMA_COMMIT_RESV:
2158 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2159 /* region_add calls of range 1 should never fail. */
2163 region_abort(resv, idx, idx + 1, 1);
2167 if (vma->vm_flags & VM_MAYSHARE) {
2168 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2169 /* region_add calls of range 1 should never fail. */
2172 region_abort(resv, idx, idx + 1, 1);
2173 ret = region_del(resv, idx, idx + 1);
2177 if (vma->vm_flags & VM_MAYSHARE) {
2178 region_abort(resv, idx, idx + 1, 1);
2179 ret = region_del(resv, idx, idx + 1);
2181 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2182 /* region_add calls of range 1 should never fail. */
2190 if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV)
2193 * We know private mapping must have HPAGE_RESV_OWNER set.
2195 * In most cases, reserves always exist for private mappings.
2196 * However, a file associated with mapping could have been
2197 * hole punched or truncated after reserves were consumed.
2198 * As subsequent fault on such a range will not use reserves.
2199 * Subtle - The reserve map for private mappings has the
2200 * opposite meaning than that of shared mappings. If NO
2201 * entry is in the reserve map, it means a reservation exists.
2202 * If an entry exists in the reserve map, it means the
2203 * reservation has already been consumed. As a result, the
2204 * return value of this routine is the opposite of the
2205 * value returned from reserve map manipulation routines above.
2214 static long vma_needs_reservation(struct hstate *h,
2215 struct vm_area_struct *vma, unsigned long addr)
2217 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2220 static long vma_commit_reservation(struct hstate *h,
2221 struct vm_area_struct *vma, unsigned long addr)
2223 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2226 static void vma_end_reservation(struct hstate *h,
2227 struct vm_area_struct *vma, unsigned long addr)
2229 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2232 static long vma_add_reservation(struct hstate *h,
2233 struct vm_area_struct *vma, unsigned long addr)
2235 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2238 static long vma_del_reservation(struct hstate *h,
2239 struct vm_area_struct *vma, unsigned long addr)
2241 return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV);
2245 * This routine is called to restore reservation information on error paths.
2246 * It should ONLY be called for pages allocated via alloc_huge_page(), and
2247 * the hugetlb mutex should remain held when calling this routine.
2249 * It handles two specific cases:
2250 * 1) A reservation was in place and the page consumed the reservation.
2251 * HPageRestoreReserve is set in the page.
2252 * 2) No reservation was in place for the page, so HPageRestoreReserve is
2253 * not set. However, alloc_huge_page always updates the reserve map.
2255 * In case 1, free_huge_page later in the error path will increment the
2256 * global reserve count. But, free_huge_page does not have enough context
2257 * to adjust the reservation map. This case deals primarily with private
2258 * mappings. Adjust the reserve map here to be consistent with global
2259 * reserve count adjustments to be made by free_huge_page. Make sure the
2260 * reserve map indicates there is a reservation present.
2262 * In case 2, simply undo reserve map modifications done by alloc_huge_page.
2264 void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
2265 unsigned long address, struct page *page)
2267 long rc = vma_needs_reservation(h, vma, address);
2269 if (HPageRestoreReserve(page)) {
2270 if (unlikely(rc < 0))
2272 * Rare out of memory condition in reserve map
2273 * manipulation. Clear HPageRestoreReserve so that
2274 * global reserve count will not be incremented
2275 * by free_huge_page. This will make it appear
2276 * as though the reservation for this page was
2277 * consumed. This may prevent the task from
2278 * faulting in the page at a later time. This
2279 * is better than inconsistent global huge page
2280 * accounting of reserve counts.
2282 ClearHPageRestoreReserve(page);
2284 (void)vma_add_reservation(h, vma, address);
2286 vma_end_reservation(h, vma, address);
2290 * This indicates there is an entry in the reserve map
2291 * added by alloc_huge_page. We know it was added
2292 * before the alloc_huge_page call, otherwise
2293 * HPageRestoreReserve would be set on the page.
2294 * Remove the entry so that a subsequent allocation
2295 * does not consume a reservation.
2297 rc = vma_del_reservation(h, vma, address);
2300 * VERY rare out of memory condition. Since
2301 * we can not delete the entry, set
2302 * HPageRestoreReserve so that the reserve
2303 * count will be incremented when the page
2304 * is freed. This reserve will be consumed
2305 * on a subsequent allocation.
2307 SetHPageRestoreReserve(page);
2308 } else if (rc < 0) {
2310 * Rare out of memory condition from
2311 * vma_needs_reservation call. Memory allocation is
2312 * only attempted if a new entry is needed. Therefore,
2313 * this implies there is not an entry in the
2316 * For shared mappings, no entry in the map indicates
2317 * no reservation. We are done.
2319 if (!(vma->vm_flags & VM_MAYSHARE))
2321 * For private mappings, no entry indicates
2322 * a reservation is present. Since we can
2323 * not add an entry, set SetHPageRestoreReserve
2324 * on the page so reserve count will be
2325 * incremented when freed. This reserve will
2326 * be consumed on a subsequent allocation.
2328 SetHPageRestoreReserve(page);
2331 * No reservation present, do nothing
2333 vma_end_reservation(h, vma, address);
2338 * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one
2339 * @h: struct hstate old page belongs to
2340 * @old_page: Old page to dissolve
2341 * @list: List to isolate the page in case we need to
2342 * Returns 0 on success, otherwise negated error.
2344 static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
2345 struct list_head *list)
2347 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2348 int nid = page_to_nid(old_page);
2349 struct page *new_page;
2353 * Before dissolving the page, we need to allocate a new one for the
2354 * pool to remain stable. Using alloc_buddy_huge_page() allows us to
2355 * not having to deal with prep_new_huge_page() and avoids dealing of any
2356 * counters. This simplifies and let us do the whole thing under the
2359 new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
2364 spin_lock_irq(&hugetlb_lock);
2365 if (!PageHuge(old_page)) {
2367 * Freed from under us. Drop new_page too.
2370 } else if (page_count(old_page)) {
2372 * Someone has grabbed the page, try to isolate it here.
2373 * Fail with -EBUSY if not possible.
2375 spin_unlock_irq(&hugetlb_lock);
2376 if (!isolate_huge_page(old_page, list))
2378 spin_lock_irq(&hugetlb_lock);
2380 } else if (!HPageFreed(old_page)) {
2382 * Page's refcount is 0 but it has not been enqueued in the
2383 * freelist yet. Race window is small, so we can succeed here if
2386 spin_unlock_irq(&hugetlb_lock);
2391 * Ok, old_page is still a genuine free hugepage. Remove it from
2392 * the freelist and decrease the counters. These will be
2393 * incremented again when calling __prep_account_new_huge_page()
2394 * and enqueue_huge_page() for new_page. The counters will remain
2395 * stable since this happens under the lock.
2397 remove_hugetlb_page(h, old_page, false);
2400 * new_page needs to be initialized with the standard hugetlb
2401 * state. This is normally done by prep_new_huge_page() but
2402 * that takes hugetlb_lock which is already held so we need to
2403 * open code it here.
2404 * Reference count trick is needed because allocator gives us
2405 * referenced page but the pool requires pages with 0 refcount.
2407 __prep_new_huge_page(new_page);
2408 __prep_account_new_huge_page(h, nid);
2409 page_ref_dec(new_page);
2410 enqueue_huge_page(h, new_page);
2413 * Pages have been replaced, we can safely free the old one.
2415 spin_unlock_irq(&hugetlb_lock);
2416 update_and_free_page(h, old_page);
2422 spin_unlock_irq(&hugetlb_lock);
2423 __free_pages(new_page, huge_page_order(h));
2428 int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
2435 * The page might have been dissolved from under our feet, so make sure
2436 * to carefully check the state under the lock.
2437 * Return success when racing as if we dissolved the page ourselves.
2439 spin_lock_irq(&hugetlb_lock);
2440 if (PageHuge(page)) {
2441 head = compound_head(page);
2442 h = page_hstate(head);
2444 spin_unlock_irq(&hugetlb_lock);
2447 spin_unlock_irq(&hugetlb_lock);
2450 * Fence off gigantic pages as there is a cyclic dependency between
2451 * alloc_contig_range and them. Return -ENOMEM as this has the effect
2452 * of bailing out right away without further retrying.
2454 if (hstate_is_gigantic(h))
2457 if (page_count(head) && isolate_huge_page(head, list))
2459 else if (!page_count(head))
2460 ret = alloc_and_dissolve_huge_page(h, head, list);
2465 struct page *alloc_huge_page(struct vm_area_struct *vma,
2466 unsigned long addr, int avoid_reserve)
2468 struct hugepage_subpool *spool = subpool_vma(vma);
2469 struct hstate *h = hstate_vma(vma);
2471 long map_chg, map_commit;
2474 struct hugetlb_cgroup *h_cg;
2475 bool deferred_reserve;
2477 idx = hstate_index(h);
2479 * Examine the region/reserve map to determine if the process
2480 * has a reservation for the page to be allocated. A return
2481 * code of zero indicates a reservation exists (no change).
2483 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2485 return ERR_PTR(-ENOMEM);
2488 * Processes that did not create the mapping will have no
2489 * reserves as indicated by the region/reserve map. Check
2490 * that the allocation will not exceed the subpool limit.
2491 * Allocations for MAP_NORESERVE mappings also need to be
2492 * checked against any subpool limit.
2494 if (map_chg || avoid_reserve) {
2495 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2497 vma_end_reservation(h, vma, addr);
2498 return ERR_PTR(-ENOSPC);
2502 * Even though there was no reservation in the region/reserve
2503 * map, there could be reservations associated with the
2504 * subpool that can be used. This would be indicated if the
2505 * return value of hugepage_subpool_get_pages() is zero.
2506 * However, if avoid_reserve is specified we still avoid even
2507 * the subpool reservations.
2513 /* If this allocation is not consuming a reservation, charge it now.
2515 deferred_reserve = map_chg || avoid_reserve;
2516 if (deferred_reserve) {
2517 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2518 idx, pages_per_huge_page(h), &h_cg);
2520 goto out_subpool_put;
2523 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2525 goto out_uncharge_cgroup_reservation;
2527 spin_lock_irq(&hugetlb_lock);
2529 * glb_chg is passed to indicate whether or not a page must be taken
2530 * from the global free pool (global change). gbl_chg == 0 indicates
2531 * a reservation exists for the allocation.
2533 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2535 spin_unlock_irq(&hugetlb_lock);
2536 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2538 goto out_uncharge_cgroup;
2539 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2540 SetHPageRestoreReserve(page);
2541 h->resv_huge_pages--;
2543 spin_lock_irq(&hugetlb_lock);
2544 list_add(&page->lru, &h->hugepage_activelist);
2547 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2548 /* If allocation is not consuming a reservation, also store the
2549 * hugetlb_cgroup pointer on the page.
2551 if (deferred_reserve) {
2552 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2556 spin_unlock_irq(&hugetlb_lock);
2558 hugetlb_set_page_subpool(page, spool);
2560 map_commit = vma_commit_reservation(h, vma, addr);
2561 if (unlikely(map_chg > map_commit)) {
2563 * The page was added to the reservation map between
2564 * vma_needs_reservation and vma_commit_reservation.
2565 * This indicates a race with hugetlb_reserve_pages.
2566 * Adjust for the subpool count incremented above AND
2567 * in hugetlb_reserve_pages for the same page. Also,
2568 * the reservation count added in hugetlb_reserve_pages
2569 * no longer applies.
2573 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2574 hugetlb_acct_memory(h, -rsv_adjust);
2575 if (deferred_reserve)
2576 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2577 pages_per_huge_page(h), page);
2581 out_uncharge_cgroup:
2582 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2583 out_uncharge_cgroup_reservation:
2584 if (deferred_reserve)
2585 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2588 if (map_chg || avoid_reserve)
2589 hugepage_subpool_put_pages(spool, 1);
2590 vma_end_reservation(h, vma, addr);
2591 return ERR_PTR(-ENOSPC);
2594 int alloc_bootmem_huge_page(struct hstate *h)
2595 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2596 int __alloc_bootmem_huge_page(struct hstate *h)
2598 struct huge_bootmem_page *m;
2601 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2604 addr = memblock_alloc_try_nid_raw(
2605 huge_page_size(h), huge_page_size(h),
2606 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2609 * Use the beginning of the huge page to store the
2610 * huge_bootmem_page struct (until gather_bootmem
2611 * puts them into the mem_map).
2620 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2621 /* Put them into a private list first because mem_map is not up yet */
2622 INIT_LIST_HEAD(&m->list);
2623 list_add(&m->list, &huge_boot_pages);
2628 static void __init prep_compound_huge_page(struct page *page,
2631 if (unlikely(order > (MAX_ORDER - 1)))
2632 prep_compound_gigantic_page(page, order);
2634 prep_compound_page(page, order);
2637 /* Put bootmem huge pages into the standard lists after mem_map is up */
2638 static void __init gather_bootmem_prealloc(void)
2640 struct huge_bootmem_page *m;
2642 list_for_each_entry(m, &huge_boot_pages, list) {
2643 struct page *page = virt_to_page(m);
2644 struct hstate *h = m->hstate;
2646 WARN_ON(page_count(page) != 1);
2647 prep_compound_huge_page(page, huge_page_order(h));
2648 WARN_ON(PageReserved(page));
2649 prep_new_huge_page(h, page, page_to_nid(page));
2650 put_page(page); /* free it into the hugepage allocator */
2653 * If we had gigantic hugepages allocated at boot time, we need
2654 * to restore the 'stolen' pages to totalram_pages in order to
2655 * fix confusing memory reports from free(1) and another
2656 * side-effects, like CommitLimit going negative.
2658 if (hstate_is_gigantic(h))
2659 adjust_managed_page_count(page, pages_per_huge_page(h));
2664 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2667 nodemask_t *node_alloc_noretry;
2669 if (!hstate_is_gigantic(h)) {
2671 * Bit mask controlling how hard we retry per-node allocations.
2672 * Ignore errors as lower level routines can deal with
2673 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2674 * time, we are likely in bigger trouble.
2676 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2679 /* allocations done at boot time */
2680 node_alloc_noretry = NULL;
2683 /* bit mask controlling how hard we retry per-node allocations */
2684 if (node_alloc_noretry)
2685 nodes_clear(*node_alloc_noretry);
2687 for (i = 0; i < h->max_huge_pages; ++i) {
2688 if (hstate_is_gigantic(h)) {
2689 if (hugetlb_cma_size) {
2690 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2693 if (!alloc_bootmem_huge_page(h))
2695 } else if (!alloc_pool_huge_page(h,
2696 &node_states[N_MEMORY],
2697 node_alloc_noretry))
2701 if (i < h->max_huge_pages) {
2704 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2705 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2706 h->max_huge_pages, buf, i);
2707 h->max_huge_pages = i;
2710 kfree(node_alloc_noretry);
2713 static void __init hugetlb_init_hstates(void)
2717 for_each_hstate(h) {
2718 if (minimum_order > huge_page_order(h))
2719 minimum_order = huge_page_order(h);
2721 /* oversize hugepages were init'ed in early boot */
2722 if (!hstate_is_gigantic(h))
2723 hugetlb_hstate_alloc_pages(h);
2725 VM_BUG_ON(minimum_order == UINT_MAX);
2728 static void __init report_hugepages(void)
2732 for_each_hstate(h) {
2735 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2736 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2737 buf, h->free_huge_pages);
2741 #ifdef CONFIG_HIGHMEM
2742 static void try_to_free_low(struct hstate *h, unsigned long count,
2743 nodemask_t *nodes_allowed)
2746 LIST_HEAD(page_list);
2748 lockdep_assert_held(&hugetlb_lock);
2749 if (hstate_is_gigantic(h))
2753 * Collect pages to be freed on a list, and free after dropping lock
2755 for_each_node_mask(i, *nodes_allowed) {
2756 struct page *page, *next;
2757 struct list_head *freel = &h->hugepage_freelists[i];
2758 list_for_each_entry_safe(page, next, freel, lru) {
2759 if (count >= h->nr_huge_pages)
2761 if (PageHighMem(page))
2763 remove_hugetlb_page(h, page, false);
2764 list_add(&page->lru, &page_list);
2769 spin_unlock_irq(&hugetlb_lock);
2770 update_and_free_pages_bulk(h, &page_list);
2771 spin_lock_irq(&hugetlb_lock);
2774 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2775 nodemask_t *nodes_allowed)
2781 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2782 * balanced by operating on them in a round-robin fashion.
2783 * Returns 1 if an adjustment was made.
2785 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2790 lockdep_assert_held(&hugetlb_lock);
2791 VM_BUG_ON(delta != -1 && delta != 1);
2794 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2795 if (h->surplus_huge_pages_node[node])
2799 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2800 if (h->surplus_huge_pages_node[node] <
2801 h->nr_huge_pages_node[node])
2808 h->surplus_huge_pages += delta;
2809 h->surplus_huge_pages_node[node] += delta;
2813 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2814 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2815 nodemask_t *nodes_allowed)
2817 unsigned long min_count, ret;
2819 LIST_HEAD(page_list);
2820 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2823 * Bit mask controlling how hard we retry per-node allocations.
2824 * If we can not allocate the bit mask, do not attempt to allocate
2825 * the requested huge pages.
2827 if (node_alloc_noretry)
2828 nodes_clear(*node_alloc_noretry);
2833 * resize_lock mutex prevents concurrent adjustments to number of
2834 * pages in hstate via the proc/sysfs interfaces.
2836 mutex_lock(&h->resize_lock);
2837 spin_lock_irq(&hugetlb_lock);
2840 * Check for a node specific request.
2841 * Changing node specific huge page count may require a corresponding
2842 * change to the global count. In any case, the passed node mask
2843 * (nodes_allowed) will restrict alloc/free to the specified node.
2845 if (nid != NUMA_NO_NODE) {
2846 unsigned long old_count = count;
2848 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2850 * User may have specified a large count value which caused the
2851 * above calculation to overflow. In this case, they wanted
2852 * to allocate as many huge pages as possible. Set count to
2853 * largest possible value to align with their intention.
2855 if (count < old_count)
2860 * Gigantic pages runtime allocation depend on the capability for large
2861 * page range allocation.
2862 * If the system does not provide this feature, return an error when
2863 * the user tries to allocate gigantic pages but let the user free the
2864 * boottime allocated gigantic pages.
2866 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2867 if (count > persistent_huge_pages(h)) {
2868 spin_unlock_irq(&hugetlb_lock);
2869 mutex_unlock(&h->resize_lock);
2870 NODEMASK_FREE(node_alloc_noretry);
2873 /* Fall through to decrease pool */
2877 * Increase the pool size
2878 * First take pages out of surplus state. Then make up the
2879 * remaining difference by allocating fresh huge pages.
2881 * We might race with alloc_surplus_huge_page() here and be unable
2882 * to convert a surplus huge page to a normal huge page. That is
2883 * not critical, though, it just means the overall size of the
2884 * pool might be one hugepage larger than it needs to be, but
2885 * within all the constraints specified by the sysctls.
2887 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2888 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2892 while (count > persistent_huge_pages(h)) {
2894 * If this allocation races such that we no longer need the
2895 * page, free_huge_page will handle it by freeing the page
2896 * and reducing the surplus.
2898 spin_unlock_irq(&hugetlb_lock);
2900 /* yield cpu to avoid soft lockup */
2903 ret = alloc_pool_huge_page(h, nodes_allowed,
2904 node_alloc_noretry);
2905 spin_lock_irq(&hugetlb_lock);
2909 /* Bail for signals. Probably ctrl-c from user */
2910 if (signal_pending(current))
2915 * Decrease the pool size
2916 * First return free pages to the buddy allocator (being careful
2917 * to keep enough around to satisfy reservations). Then place
2918 * pages into surplus state as needed so the pool will shrink
2919 * to the desired size as pages become free.
2921 * By placing pages into the surplus state independent of the
2922 * overcommit value, we are allowing the surplus pool size to
2923 * exceed overcommit. There are few sane options here. Since
2924 * alloc_surplus_huge_page() is checking the global counter,
2925 * though, we'll note that we're not allowed to exceed surplus
2926 * and won't grow the pool anywhere else. Not until one of the
2927 * sysctls are changed, or the surplus pages go out of use.
2929 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2930 min_count = max(count, min_count);
2931 try_to_free_low(h, min_count, nodes_allowed);
2934 * Collect pages to be removed on list without dropping lock
2936 while (min_count < persistent_huge_pages(h)) {
2937 page = remove_pool_huge_page(h, nodes_allowed, 0);
2941 list_add(&page->lru, &page_list);
2943 /* free the pages after dropping lock */
2944 spin_unlock_irq(&hugetlb_lock);
2945 update_and_free_pages_bulk(h, &page_list);
2946 spin_lock_irq(&hugetlb_lock);
2948 while (count < persistent_huge_pages(h)) {
2949 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2953 h->max_huge_pages = persistent_huge_pages(h);
2954 spin_unlock_irq(&hugetlb_lock);
2955 mutex_unlock(&h->resize_lock);
2957 NODEMASK_FREE(node_alloc_noretry);
2962 #define HSTATE_ATTR_RO(_name) \
2963 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2965 #define HSTATE_ATTR(_name) \
2966 static struct kobj_attribute _name##_attr = \
2967 __ATTR(_name, 0644, _name##_show, _name##_store)
2969 static struct kobject *hugepages_kobj;
2970 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2972 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2974 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2978 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2979 if (hstate_kobjs[i] == kobj) {
2981 *nidp = NUMA_NO_NODE;
2985 return kobj_to_node_hstate(kobj, nidp);
2988 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2989 struct kobj_attribute *attr, char *buf)
2992 unsigned long nr_huge_pages;
2995 h = kobj_to_hstate(kobj, &nid);
2996 if (nid == NUMA_NO_NODE)
2997 nr_huge_pages = h->nr_huge_pages;
2999 nr_huge_pages = h->nr_huge_pages_node[nid];
3001 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
3004 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
3005 struct hstate *h, int nid,
3006 unsigned long count, size_t len)
3009 nodemask_t nodes_allowed, *n_mask;
3011 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
3014 if (nid == NUMA_NO_NODE) {
3016 * global hstate attribute
3018 if (!(obey_mempolicy &&
3019 init_nodemask_of_mempolicy(&nodes_allowed)))
3020 n_mask = &node_states[N_MEMORY];
3022 n_mask = &nodes_allowed;
3025 * Node specific request. count adjustment happens in
3026 * set_max_huge_pages() after acquiring hugetlb_lock.
3028 init_nodemask_of_node(&nodes_allowed, nid);
3029 n_mask = &nodes_allowed;
3032 err = set_max_huge_pages(h, count, nid, n_mask);
3034 return err ? err : len;
3037 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
3038 struct kobject *kobj, const char *buf,
3042 unsigned long count;
3046 err = kstrtoul(buf, 10, &count);
3050 h = kobj_to_hstate(kobj, &nid);
3051 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
3054 static ssize_t nr_hugepages_show(struct kobject *kobj,
3055 struct kobj_attribute *attr, char *buf)
3057 return nr_hugepages_show_common(kobj, attr, buf);
3060 static ssize_t nr_hugepages_store(struct kobject *kobj,
3061 struct kobj_attribute *attr, const char *buf, size_t len)
3063 return nr_hugepages_store_common(false, kobj, buf, len);
3065 HSTATE_ATTR(nr_hugepages);
3070 * hstate attribute for optionally mempolicy-based constraint on persistent
3071 * huge page alloc/free.
3073 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
3074 struct kobj_attribute *attr,
3077 return nr_hugepages_show_common(kobj, attr, buf);
3080 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
3081 struct kobj_attribute *attr, const char *buf, size_t len)
3083 return nr_hugepages_store_common(true, kobj, buf, len);
3085 HSTATE_ATTR(nr_hugepages_mempolicy);
3089 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
3090 struct kobj_attribute *attr, char *buf)
3092 struct hstate *h = kobj_to_hstate(kobj, NULL);
3093 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
3096 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
3097 struct kobj_attribute *attr, const char *buf, size_t count)
3100 unsigned long input;
3101 struct hstate *h = kobj_to_hstate(kobj, NULL);
3103 if (hstate_is_gigantic(h))
3106 err = kstrtoul(buf, 10, &input);
3110 spin_lock_irq(&hugetlb_lock);
3111 h->nr_overcommit_huge_pages = input;
3112 spin_unlock_irq(&hugetlb_lock);
3116 HSTATE_ATTR(nr_overcommit_hugepages);
3118 static ssize_t free_hugepages_show(struct kobject *kobj,
3119 struct kobj_attribute *attr, char *buf)
3122 unsigned long free_huge_pages;
3125 h = kobj_to_hstate(kobj, &nid);
3126 if (nid == NUMA_NO_NODE)
3127 free_huge_pages = h->free_huge_pages;
3129 free_huge_pages = h->free_huge_pages_node[nid];
3131 return sysfs_emit(buf, "%lu\n", free_huge_pages);
3133 HSTATE_ATTR_RO(free_hugepages);
3135 static ssize_t resv_hugepages_show(struct kobject *kobj,
3136 struct kobj_attribute *attr, char *buf)
3138 struct hstate *h = kobj_to_hstate(kobj, NULL);
3139 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
3141 HSTATE_ATTR_RO(resv_hugepages);
3143 static ssize_t surplus_hugepages_show(struct kobject *kobj,
3144 struct kobj_attribute *attr, char *buf)
3147 unsigned long surplus_huge_pages;
3150 h = kobj_to_hstate(kobj, &nid);
3151 if (nid == NUMA_NO_NODE)
3152 surplus_huge_pages = h->surplus_huge_pages;
3154 surplus_huge_pages = h->surplus_huge_pages_node[nid];
3156 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
3158 HSTATE_ATTR_RO(surplus_hugepages);
3160 static struct attribute *hstate_attrs[] = {
3161 &nr_hugepages_attr.attr,
3162 &nr_overcommit_hugepages_attr.attr,
3163 &free_hugepages_attr.attr,
3164 &resv_hugepages_attr.attr,
3165 &surplus_hugepages_attr.attr,
3167 &nr_hugepages_mempolicy_attr.attr,
3172 static const struct attribute_group hstate_attr_group = {
3173 .attrs = hstate_attrs,
3176 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
3177 struct kobject **hstate_kobjs,
3178 const struct attribute_group *hstate_attr_group)
3181 int hi = hstate_index(h);
3183 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3184 if (!hstate_kobjs[hi])
3187 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3189 kobject_put(hstate_kobjs[hi]);
3190 hstate_kobjs[hi] = NULL;
3196 static void __init hugetlb_sysfs_init(void)
3201 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3202 if (!hugepages_kobj)
3205 for_each_hstate(h) {
3206 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3207 hstate_kobjs, &hstate_attr_group);
3209 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3216 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3217 * with node devices in node_devices[] using a parallel array. The array
3218 * index of a node device or _hstate == node id.
3219 * This is here to avoid any static dependency of the node device driver, in
3220 * the base kernel, on the hugetlb module.
3222 struct node_hstate {
3223 struct kobject *hugepages_kobj;
3224 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3226 static struct node_hstate node_hstates[MAX_NUMNODES];
3229 * A subset of global hstate attributes for node devices
3231 static struct attribute *per_node_hstate_attrs[] = {
3232 &nr_hugepages_attr.attr,
3233 &free_hugepages_attr.attr,
3234 &surplus_hugepages_attr.attr,
3238 static const struct attribute_group per_node_hstate_attr_group = {
3239 .attrs = per_node_hstate_attrs,
3243 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3244 * Returns node id via non-NULL nidp.
3246 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3250 for (nid = 0; nid < nr_node_ids; nid++) {
3251 struct node_hstate *nhs = &node_hstates[nid];
3253 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3254 if (nhs->hstate_kobjs[i] == kobj) {
3266 * Unregister hstate attributes from a single node device.
3267 * No-op if no hstate attributes attached.
3269 static void hugetlb_unregister_node(struct node *node)
3272 struct node_hstate *nhs = &node_hstates[node->dev.id];
3274 if (!nhs->hugepages_kobj)
3275 return; /* no hstate attributes */
3277 for_each_hstate(h) {
3278 int idx = hstate_index(h);
3279 if (nhs->hstate_kobjs[idx]) {
3280 kobject_put(nhs->hstate_kobjs[idx]);
3281 nhs->hstate_kobjs[idx] = NULL;
3285 kobject_put(nhs->hugepages_kobj);
3286 nhs->hugepages_kobj = NULL;
3291 * Register hstate attributes for a single node device.
3292 * No-op if attributes already registered.
3294 static void hugetlb_register_node(struct node *node)
3297 struct node_hstate *nhs = &node_hstates[node->dev.id];
3300 if (nhs->hugepages_kobj)
3301 return; /* already allocated */
3303 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3305 if (!nhs->hugepages_kobj)
3308 for_each_hstate(h) {
3309 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3311 &per_node_hstate_attr_group);
3313 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3314 h->name, node->dev.id);
3315 hugetlb_unregister_node(node);
3322 * hugetlb init time: register hstate attributes for all registered node
3323 * devices of nodes that have memory. All on-line nodes should have
3324 * registered their associated device by this time.
3326 static void __init hugetlb_register_all_nodes(void)
3330 for_each_node_state(nid, N_MEMORY) {
3331 struct node *node = node_devices[nid];
3332 if (node->dev.id == nid)
3333 hugetlb_register_node(node);
3337 * Let the node device driver know we're here so it can
3338 * [un]register hstate attributes on node hotplug.
3340 register_hugetlbfs_with_node(hugetlb_register_node,
3341 hugetlb_unregister_node);
3343 #else /* !CONFIG_NUMA */
3345 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3353 static void hugetlb_register_all_nodes(void) { }
3357 static int __init hugetlb_init(void)
3361 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3364 if (!hugepages_supported()) {
3365 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3366 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3371 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3372 * architectures depend on setup being done here.
3374 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3375 if (!parsed_default_hugepagesz) {
3377 * If we did not parse a default huge page size, set
3378 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3379 * number of huge pages for this default size was implicitly
3380 * specified, set that here as well.
3381 * Note that the implicit setting will overwrite an explicit
3382 * setting. A warning will be printed in this case.
3384 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3385 if (default_hstate_max_huge_pages) {
3386 if (default_hstate.max_huge_pages) {
3389 string_get_size(huge_page_size(&default_hstate),
3390 1, STRING_UNITS_2, buf, 32);
3391 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3392 default_hstate.max_huge_pages, buf);
3393 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3394 default_hstate_max_huge_pages);
3396 default_hstate.max_huge_pages =
3397 default_hstate_max_huge_pages;
3401 hugetlb_cma_check();
3402 hugetlb_init_hstates();
3403 gather_bootmem_prealloc();
3406 hugetlb_sysfs_init();
3407 hugetlb_register_all_nodes();
3408 hugetlb_cgroup_file_init();
3411 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3413 num_fault_mutexes = 1;
3415 hugetlb_fault_mutex_table =
3416 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3418 BUG_ON(!hugetlb_fault_mutex_table);
3420 for (i = 0; i < num_fault_mutexes; i++)
3421 mutex_init(&hugetlb_fault_mutex_table[i]);
3424 subsys_initcall(hugetlb_init);
3426 /* Overwritten by architectures with more huge page sizes */
3427 bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3429 return size == HPAGE_SIZE;
3432 void __init hugetlb_add_hstate(unsigned int order)
3437 if (size_to_hstate(PAGE_SIZE << order)) {
3440 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3442 h = &hstates[hugetlb_max_hstate++];
3443 mutex_init(&h->resize_lock);
3445 h->mask = ~(huge_page_size(h) - 1);
3446 for (i = 0; i < MAX_NUMNODES; ++i)
3447 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3448 INIT_LIST_HEAD(&h->hugepage_activelist);
3449 h->next_nid_to_alloc = first_memory_node;
3450 h->next_nid_to_free = first_memory_node;
3451 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3452 huge_page_size(h)/1024);
3458 * hugepages command line processing
3459 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3460 * specification. If not, ignore the hugepages value. hugepages can also
3461 * be the first huge page command line option in which case it implicitly
3462 * specifies the number of huge pages for the default size.
3464 static int __init hugepages_setup(char *s)
3467 static unsigned long *last_mhp;
3469 if (!parsed_valid_hugepagesz) {
3470 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3471 parsed_valid_hugepagesz = true;
3476 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3477 * yet, so this hugepages= parameter goes to the "default hstate".
3478 * Otherwise, it goes with the previously parsed hugepagesz or
3479 * default_hugepagesz.
3481 else if (!hugetlb_max_hstate)
3482 mhp = &default_hstate_max_huge_pages;
3484 mhp = &parsed_hstate->max_huge_pages;
3486 if (mhp == last_mhp) {
3487 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3491 if (sscanf(s, "%lu", mhp) <= 0)
3495 * Global state is always initialized later in hugetlb_init.
3496 * But we need to allocate gigantic hstates here early to still
3497 * use the bootmem allocator.
3499 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
3500 hugetlb_hstate_alloc_pages(parsed_hstate);
3506 __setup("hugepages=", hugepages_setup);
3509 * hugepagesz command line processing
3510 * A specific huge page size can only be specified once with hugepagesz.
3511 * hugepagesz is followed by hugepages on the command line. The global
3512 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3513 * hugepagesz argument was valid.
3515 static int __init hugepagesz_setup(char *s)
3520 parsed_valid_hugepagesz = false;
3521 size = (unsigned long)memparse(s, NULL);
3523 if (!arch_hugetlb_valid_size(size)) {
3524 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3528 h = size_to_hstate(size);
3531 * hstate for this size already exists. This is normally
3532 * an error, but is allowed if the existing hstate is the
3533 * default hstate. More specifically, it is only allowed if
3534 * the number of huge pages for the default hstate was not
3535 * previously specified.
3537 if (!parsed_default_hugepagesz || h != &default_hstate ||
3538 default_hstate.max_huge_pages) {
3539 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3544 * No need to call hugetlb_add_hstate() as hstate already
3545 * exists. But, do set parsed_hstate so that a following
3546 * hugepages= parameter will be applied to this hstate.
3549 parsed_valid_hugepagesz = true;
3553 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3554 parsed_valid_hugepagesz = true;
3557 __setup("hugepagesz=", hugepagesz_setup);
3560 * default_hugepagesz command line input
3561 * Only one instance of default_hugepagesz allowed on command line.
3563 static int __init default_hugepagesz_setup(char *s)
3567 parsed_valid_hugepagesz = false;
3568 if (parsed_default_hugepagesz) {
3569 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3573 size = (unsigned long)memparse(s, NULL);
3575 if (!arch_hugetlb_valid_size(size)) {
3576 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3580 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3581 parsed_valid_hugepagesz = true;
3582 parsed_default_hugepagesz = true;
3583 default_hstate_idx = hstate_index(size_to_hstate(size));
3586 * The number of default huge pages (for this size) could have been
3587 * specified as the first hugetlb parameter: hugepages=X. If so,
3588 * then default_hstate_max_huge_pages is set. If the default huge
3589 * page size is gigantic (>= MAX_ORDER), then the pages must be
3590 * allocated here from bootmem allocator.
3592 if (default_hstate_max_huge_pages) {
3593 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3594 if (hstate_is_gigantic(&default_hstate))
3595 hugetlb_hstate_alloc_pages(&default_hstate);
3596 default_hstate_max_huge_pages = 0;
3601 __setup("default_hugepagesz=", default_hugepagesz_setup);
3603 static unsigned int allowed_mems_nr(struct hstate *h)
3606 unsigned int nr = 0;
3607 nodemask_t *mpol_allowed;
3608 unsigned int *array = h->free_huge_pages_node;
3609 gfp_t gfp_mask = htlb_alloc_mask(h);
3611 mpol_allowed = policy_nodemask_current(gfp_mask);
3613 for_each_node_mask(node, cpuset_current_mems_allowed) {
3614 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3621 #ifdef CONFIG_SYSCTL
3622 static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3623 void *buffer, size_t *length,
3624 loff_t *ppos, unsigned long *out)
3626 struct ctl_table dup_table;
3629 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3630 * can duplicate the @table and alter the duplicate of it.
3633 dup_table.data = out;
3635 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3638 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3639 struct ctl_table *table, int write,
3640 void *buffer, size_t *length, loff_t *ppos)
3642 struct hstate *h = &default_hstate;
3643 unsigned long tmp = h->max_huge_pages;
3646 if (!hugepages_supported())
3649 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3655 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3656 NUMA_NO_NODE, tmp, *length);
3661 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3662 void *buffer, size_t *length, loff_t *ppos)
3665 return hugetlb_sysctl_handler_common(false, table, write,
3666 buffer, length, ppos);
3670 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3671 void *buffer, size_t *length, loff_t *ppos)
3673 return hugetlb_sysctl_handler_common(true, table, write,
3674 buffer, length, ppos);
3676 #endif /* CONFIG_NUMA */
3678 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3679 void *buffer, size_t *length, loff_t *ppos)
3681 struct hstate *h = &default_hstate;
3685 if (!hugepages_supported())
3688 tmp = h->nr_overcommit_huge_pages;
3690 if (write && hstate_is_gigantic(h))
3693 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3699 spin_lock_irq(&hugetlb_lock);
3700 h->nr_overcommit_huge_pages = tmp;
3701 spin_unlock_irq(&hugetlb_lock);
3707 #endif /* CONFIG_SYSCTL */
3709 void hugetlb_report_meminfo(struct seq_file *m)
3712 unsigned long total = 0;
3714 if (!hugepages_supported())
3717 for_each_hstate(h) {
3718 unsigned long count = h->nr_huge_pages;
3720 total += huge_page_size(h) * count;
3722 if (h == &default_hstate)
3724 "HugePages_Total: %5lu\n"
3725 "HugePages_Free: %5lu\n"
3726 "HugePages_Rsvd: %5lu\n"
3727 "HugePages_Surp: %5lu\n"
3728 "Hugepagesize: %8lu kB\n",
3732 h->surplus_huge_pages,
3733 huge_page_size(h) / SZ_1K);
3736 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3739 int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3741 struct hstate *h = &default_hstate;
3743 if (!hugepages_supported())
3746 return sysfs_emit_at(buf, len,
3747 "Node %d HugePages_Total: %5u\n"
3748 "Node %d HugePages_Free: %5u\n"
3749 "Node %d HugePages_Surp: %5u\n",
3750 nid, h->nr_huge_pages_node[nid],
3751 nid, h->free_huge_pages_node[nid],
3752 nid, h->surplus_huge_pages_node[nid]);
3755 void hugetlb_show_meminfo(void)
3760 if (!hugepages_supported())
3763 for_each_node_state(nid, N_MEMORY)
3765 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3767 h->nr_huge_pages_node[nid],
3768 h->free_huge_pages_node[nid],
3769 h->surplus_huge_pages_node[nid],
3770 huge_page_size(h) / SZ_1K);
3773 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3775 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3776 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3779 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3780 unsigned long hugetlb_total_pages(void)
3783 unsigned long nr_total_pages = 0;
3786 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3787 return nr_total_pages;
3790 static int hugetlb_acct_memory(struct hstate *h, long delta)
3797 spin_lock_irq(&hugetlb_lock);
3799 * When cpuset is configured, it breaks the strict hugetlb page
3800 * reservation as the accounting is done on a global variable. Such
3801 * reservation is completely rubbish in the presence of cpuset because
3802 * the reservation is not checked against page availability for the
3803 * current cpuset. Application can still potentially OOM'ed by kernel
3804 * with lack of free htlb page in cpuset that the task is in.
3805 * Attempt to enforce strict accounting with cpuset is almost
3806 * impossible (or too ugly) because cpuset is too fluid that
3807 * task or memory node can be dynamically moved between cpusets.
3809 * The change of semantics for shared hugetlb mapping with cpuset is
3810 * undesirable. However, in order to preserve some of the semantics,
3811 * we fall back to check against current free page availability as
3812 * a best attempt and hopefully to minimize the impact of changing
3813 * semantics that cpuset has.
3815 * Apart from cpuset, we also have memory policy mechanism that
3816 * also determines from which node the kernel will allocate memory
3817 * in a NUMA system. So similar to cpuset, we also should consider
3818 * the memory policy of the current task. Similar to the description
3822 if (gather_surplus_pages(h, delta) < 0)
3825 if (delta > allowed_mems_nr(h)) {
3826 return_unused_surplus_pages(h, delta);
3833 return_unused_surplus_pages(h, (unsigned long) -delta);
3836 spin_unlock_irq(&hugetlb_lock);
3840 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3842 struct resv_map *resv = vma_resv_map(vma);
3845 * This new VMA should share its siblings reservation map if present.
3846 * The VMA will only ever have a valid reservation map pointer where
3847 * it is being copied for another still existing VMA. As that VMA
3848 * has a reference to the reservation map it cannot disappear until
3849 * after this open call completes. It is therefore safe to take a
3850 * new reference here without additional locking.
3852 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3853 kref_get(&resv->refs);
3856 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3858 struct hstate *h = hstate_vma(vma);
3859 struct resv_map *resv = vma_resv_map(vma);
3860 struct hugepage_subpool *spool = subpool_vma(vma);
3861 unsigned long reserve, start, end;
3864 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3867 start = vma_hugecache_offset(h, vma, vma->vm_start);
3868 end = vma_hugecache_offset(h, vma, vma->vm_end);
3870 reserve = (end - start) - region_count(resv, start, end);
3871 hugetlb_cgroup_uncharge_counter(resv, start, end);
3874 * Decrement reserve counts. The global reserve count may be
3875 * adjusted if the subpool has a minimum size.
3877 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3878 hugetlb_acct_memory(h, -gbl_reserve);
3881 kref_put(&resv->refs, resv_map_release);
3884 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3886 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3891 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3893 return huge_page_size(hstate_vma(vma));
3897 * We cannot handle pagefaults against hugetlb pages at all. They cause
3898 * handle_mm_fault() to try to instantiate regular-sized pages in the
3899 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3902 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3909 * When a new function is introduced to vm_operations_struct and added
3910 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3911 * This is because under System V memory model, mappings created via
3912 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3913 * their original vm_ops are overwritten with shm_vm_ops.
3915 const struct vm_operations_struct hugetlb_vm_ops = {
3916 .fault = hugetlb_vm_op_fault,
3917 .open = hugetlb_vm_op_open,
3918 .close = hugetlb_vm_op_close,
3919 .may_split = hugetlb_vm_op_split,
3920 .pagesize = hugetlb_vm_op_pagesize,
3923 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3929 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3930 vma->vm_page_prot)));
3932 entry = huge_pte_wrprotect(mk_huge_pte(page,
3933 vma->vm_page_prot));
3935 entry = pte_mkyoung(entry);
3936 entry = pte_mkhuge(entry);
3937 entry = arch_make_huge_pte(entry, vma, page, writable);
3942 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3943 unsigned long address, pte_t *ptep)
3947 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3948 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3949 update_mmu_cache(vma, address, ptep);
3952 bool is_hugetlb_entry_migration(pte_t pte)
3956 if (huge_pte_none(pte) || pte_present(pte))
3958 swp = pte_to_swp_entry(pte);
3959 if (is_migration_entry(swp))
3965 static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3969 if (huge_pte_none(pte) || pte_present(pte))
3971 swp = pte_to_swp_entry(pte);
3972 if (is_hwpoison_entry(swp))
3979 hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
3980 struct page *new_page)
3982 __SetPageUptodate(new_page);
3983 set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1));
3984 hugepage_add_new_anon_rmap(new_page, vma, addr);
3985 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
3986 ClearHPageRestoreReserve(new_page);
3987 SetHPageMigratable(new_page);
3990 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3991 struct vm_area_struct *vma)
3993 pte_t *src_pte, *dst_pte, entry, dst_entry;
3994 struct page *ptepage;
3996 bool cow = is_cow_mapping(vma->vm_flags);
3997 struct hstate *h = hstate_vma(vma);
3998 unsigned long sz = huge_page_size(h);
3999 unsigned long npages = pages_per_huge_page(h);
4000 struct address_space *mapping = vma->vm_file->f_mapping;
4001 struct mmu_notifier_range range;
4005 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
4008 mmu_notifier_invalidate_range_start(&range);
4011 * For shared mappings i_mmap_rwsem must be held to call
4012 * huge_pte_alloc, otherwise the returned ptep could go
4013 * away if part of a shared pmd and another thread calls
4016 i_mmap_lock_read(mapping);
4019 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
4020 spinlock_t *src_ptl, *dst_ptl;
4021 src_pte = huge_pte_offset(src, addr, sz);
4024 dst_pte = huge_pte_alloc(dst, vma, addr, sz);
4031 * If the pagetables are shared don't copy or take references.
4032 * dst_pte == src_pte is the common case of src/dest sharing.
4034 * However, src could have 'unshared' and dst shares with
4035 * another vma. If dst_pte !none, this implies sharing.
4036 * Check here before taking page table lock, and once again
4037 * after taking the lock below.
4039 dst_entry = huge_ptep_get(dst_pte);
4040 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
4043 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4044 src_ptl = huge_pte_lockptr(h, src, src_pte);
4045 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4046 entry = huge_ptep_get(src_pte);
4047 dst_entry = huge_ptep_get(dst_pte);
4049 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
4051 * Skip if src entry none. Also, skip in the
4052 * unlikely case dst entry !none as this implies
4053 * sharing with another vma.
4056 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
4057 is_hugetlb_entry_hwpoisoned(entry))) {
4058 swp_entry_t swp_entry = pte_to_swp_entry(entry);
4060 if (is_write_migration_entry(swp_entry) && cow) {
4062 * COW mappings require pages in both
4063 * parent and child to be set to read.
4065 make_migration_entry_read(&swp_entry);
4066 entry = swp_entry_to_pte(swp_entry);
4067 set_huge_swap_pte_at(src, addr, src_pte,
4070 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
4072 entry = huge_ptep_get(src_pte);
4073 ptepage = pte_page(entry);
4077 * This is a rare case where we see pinned hugetlb
4078 * pages while they're prone to COW. We need to do the
4079 * COW earlier during fork.
4081 * When pre-allocating the page or copying data, we
4082 * need to be without the pgtable locks since we could
4083 * sleep during the process.
4085 if (unlikely(page_needs_cow_for_dma(vma, ptepage))) {
4086 pte_t src_pte_old = entry;
4089 spin_unlock(src_ptl);
4090 spin_unlock(dst_ptl);
4091 /* Do not use reserve as it's private owned */
4092 new = alloc_huge_page(vma, addr, 1);
4098 copy_user_huge_page(new, ptepage, addr, vma,
4102 /* Install the new huge page if src pte stable */
4103 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4104 src_ptl = huge_pte_lockptr(h, src, src_pte);
4105 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4106 entry = huge_ptep_get(src_pte);
4107 if (!pte_same(src_pte_old, entry)) {
4108 restore_reserve_on_error(h, vma, addr,
4111 /* dst_entry won't change as in child */
4114 hugetlb_install_page(vma, dst_pte, addr, new);
4115 spin_unlock(src_ptl);
4116 spin_unlock(dst_ptl);
4122 * No need to notify as we are downgrading page
4123 * table protection not changing it to point
4126 * See Documentation/vm/mmu_notifier.rst
4128 huge_ptep_set_wrprotect(src, addr, src_pte);
4129 entry = huge_pte_wrprotect(entry);
4132 page_dup_rmap(ptepage, true);
4133 set_huge_pte_at(dst, addr, dst_pte, entry);
4134 hugetlb_count_add(npages, dst);
4136 spin_unlock(src_ptl);
4137 spin_unlock(dst_ptl);
4141 mmu_notifier_invalidate_range_end(&range);
4143 i_mmap_unlock_read(mapping);
4148 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
4149 unsigned long start, unsigned long end,
4150 struct page *ref_page)
4152 struct mm_struct *mm = vma->vm_mm;
4153 unsigned long address;
4158 struct hstate *h = hstate_vma(vma);
4159 unsigned long sz = huge_page_size(h);
4160 struct mmu_notifier_range range;
4162 WARN_ON(!is_vm_hugetlb_page(vma));
4163 BUG_ON(start & ~huge_page_mask(h));
4164 BUG_ON(end & ~huge_page_mask(h));
4167 * This is a hugetlb vma, all the pte entries should point
4170 tlb_change_page_size(tlb, sz);
4171 tlb_start_vma(tlb, vma);
4174 * If sharing possible, alert mmu notifiers of worst case.
4176 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
4178 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4179 mmu_notifier_invalidate_range_start(&range);
4181 for (; address < end; address += sz) {
4182 ptep = huge_pte_offset(mm, address, sz);
4186 ptl = huge_pte_lock(h, mm, ptep);
4187 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
4190 * We just unmapped a page of PMDs by clearing a PUD.
4191 * The caller's TLB flush range should cover this area.
4196 pte = huge_ptep_get(ptep);
4197 if (huge_pte_none(pte)) {
4203 * Migrating hugepage or HWPoisoned hugepage is already
4204 * unmapped and its refcount is dropped, so just clear pte here.
4206 if (unlikely(!pte_present(pte))) {
4207 huge_pte_clear(mm, address, ptep, sz);
4212 page = pte_page(pte);
4214 * If a reference page is supplied, it is because a specific
4215 * page is being unmapped, not a range. Ensure the page we
4216 * are about to unmap is the actual page of interest.
4219 if (page != ref_page) {
4224 * Mark the VMA as having unmapped its page so that
4225 * future faults in this VMA will fail rather than
4226 * looking like data was lost
4228 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4231 pte = huge_ptep_get_and_clear(mm, address, ptep);
4232 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4233 if (huge_pte_dirty(pte))
4234 set_page_dirty(page);
4236 hugetlb_count_sub(pages_per_huge_page(h), mm);
4237 page_remove_rmap(page, true);
4240 tlb_remove_page_size(tlb, page, huge_page_size(h));
4242 * Bail out after unmapping reference page if supplied
4247 mmu_notifier_invalidate_range_end(&range);
4248 tlb_end_vma(tlb, vma);
4251 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4252 struct vm_area_struct *vma, unsigned long start,
4253 unsigned long end, struct page *ref_page)
4255 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4258 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4259 * test will fail on a vma being torn down, and not grab a page table
4260 * on its way out. We're lucky that the flag has such an appropriate
4261 * name, and can in fact be safely cleared here. We could clear it
4262 * before the __unmap_hugepage_range above, but all that's necessary
4263 * is to clear it before releasing the i_mmap_rwsem. This works
4264 * because in the context this is called, the VMA is about to be
4265 * destroyed and the i_mmap_rwsem is held.
4267 vma->vm_flags &= ~VM_MAYSHARE;
4270 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4271 unsigned long end, struct page *ref_page)
4273 struct mmu_gather tlb;
4275 tlb_gather_mmu(&tlb, vma->vm_mm);
4276 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4277 tlb_finish_mmu(&tlb);
4281 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4282 * mapping it owns the reserve page for. The intention is to unmap the page
4283 * from other VMAs and let the children be SIGKILLed if they are faulting the
4286 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4287 struct page *page, unsigned long address)
4289 struct hstate *h = hstate_vma(vma);
4290 struct vm_area_struct *iter_vma;
4291 struct address_space *mapping;
4295 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4296 * from page cache lookup which is in HPAGE_SIZE units.
4298 address = address & huge_page_mask(h);
4299 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4301 mapping = vma->vm_file->f_mapping;
4304 * Take the mapping lock for the duration of the table walk. As
4305 * this mapping should be shared between all the VMAs,
4306 * __unmap_hugepage_range() is called as the lock is already held
4308 i_mmap_lock_write(mapping);
4309 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4310 /* Do not unmap the current VMA */
4311 if (iter_vma == vma)
4315 * Shared VMAs have their own reserves and do not affect
4316 * MAP_PRIVATE accounting but it is possible that a shared
4317 * VMA is using the same page so check and skip such VMAs.
4319 if (iter_vma->vm_flags & VM_MAYSHARE)
4323 * Unmap the page from other VMAs without their own reserves.
4324 * They get marked to be SIGKILLed if they fault in these
4325 * areas. This is because a future no-page fault on this VMA
4326 * could insert a zeroed page instead of the data existing
4327 * from the time of fork. This would look like data corruption
4329 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4330 unmap_hugepage_range(iter_vma, address,
4331 address + huge_page_size(h), page);
4333 i_mmap_unlock_write(mapping);
4337 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4338 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4339 * cannot race with other handlers or page migration.
4340 * Keep the pte_same checks anyway to make transition from the mutex easier.
4342 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4343 unsigned long address, pte_t *ptep,
4344 struct page *pagecache_page, spinlock_t *ptl)
4347 struct hstate *h = hstate_vma(vma);
4348 struct page *old_page, *new_page;
4349 int outside_reserve = 0;
4351 unsigned long haddr = address & huge_page_mask(h);
4352 struct mmu_notifier_range range;
4354 pte = huge_ptep_get(ptep);
4355 old_page = pte_page(pte);
4358 /* If no-one else is actually using this page, avoid the copy
4359 * and just make the page writable */
4360 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4361 page_move_anon_rmap(old_page, vma);
4362 set_huge_ptep_writable(vma, haddr, ptep);
4367 * If the process that created a MAP_PRIVATE mapping is about to
4368 * perform a COW due to a shared page count, attempt to satisfy
4369 * the allocation without using the existing reserves. The pagecache
4370 * page is used to determine if the reserve at this address was
4371 * consumed or not. If reserves were used, a partial faulted mapping
4372 * at the time of fork() could consume its reserves on COW instead
4373 * of the full address range.
4375 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4376 old_page != pagecache_page)
4377 outside_reserve = 1;
4382 * Drop page table lock as buddy allocator may be called. It will
4383 * be acquired again before returning to the caller, as expected.
4386 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4388 if (IS_ERR(new_page)) {
4390 * If a process owning a MAP_PRIVATE mapping fails to COW,
4391 * it is due to references held by a child and an insufficient
4392 * huge page pool. To guarantee the original mappers
4393 * reliability, unmap the page from child processes. The child
4394 * may get SIGKILLed if it later faults.
4396 if (outside_reserve) {
4397 struct address_space *mapping = vma->vm_file->f_mapping;
4402 BUG_ON(huge_pte_none(pte));
4404 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4405 * unmapping. unmapping needs to hold i_mmap_rwsem
4406 * in write mode. Dropping i_mmap_rwsem in read mode
4407 * here is OK as COW mappings do not interact with
4410 * Reacquire both after unmap operation.
4412 idx = vma_hugecache_offset(h, vma, haddr);
4413 hash = hugetlb_fault_mutex_hash(mapping, idx);
4414 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4415 i_mmap_unlock_read(mapping);
4417 unmap_ref_private(mm, vma, old_page, haddr);
4419 i_mmap_lock_read(mapping);
4420 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4422 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4424 pte_same(huge_ptep_get(ptep), pte)))
4425 goto retry_avoidcopy;
4427 * race occurs while re-acquiring page table
4428 * lock, and our job is done.
4433 ret = vmf_error(PTR_ERR(new_page));
4434 goto out_release_old;
4438 * When the original hugepage is shared one, it does not have
4439 * anon_vma prepared.
4441 if (unlikely(anon_vma_prepare(vma))) {
4443 goto out_release_all;
4446 copy_user_huge_page(new_page, old_page, address, vma,
4447 pages_per_huge_page(h));
4448 __SetPageUptodate(new_page);
4450 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4451 haddr + huge_page_size(h));
4452 mmu_notifier_invalidate_range_start(&range);
4455 * Retake the page table lock to check for racing updates
4456 * before the page tables are altered
4459 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4460 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4461 ClearHPageRestoreReserve(new_page);
4464 huge_ptep_clear_flush(vma, haddr, ptep);
4465 mmu_notifier_invalidate_range(mm, range.start, range.end);
4466 set_huge_pte_at(mm, haddr, ptep,
4467 make_huge_pte(vma, new_page, 1));
4468 page_remove_rmap(old_page, true);
4469 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4470 SetHPageMigratable(new_page);
4471 /* Make the old page be freed below */
4472 new_page = old_page;
4475 mmu_notifier_invalidate_range_end(&range);
4477 restore_reserve_on_error(h, vma, haddr, new_page);
4482 spin_lock(ptl); /* Caller expects lock to be held */
4486 /* Return the pagecache page at a given address within a VMA */
4487 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4488 struct vm_area_struct *vma, unsigned long address)
4490 struct address_space *mapping;
4493 mapping = vma->vm_file->f_mapping;
4494 idx = vma_hugecache_offset(h, vma, address);
4496 return find_lock_page(mapping, idx);
4500 * Return whether there is a pagecache page to back given address within VMA.
4501 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4503 static bool hugetlbfs_pagecache_present(struct hstate *h,
4504 struct vm_area_struct *vma, unsigned long address)
4506 struct address_space *mapping;
4510 mapping = vma->vm_file->f_mapping;
4511 idx = vma_hugecache_offset(h, vma, address);
4513 page = find_get_page(mapping, idx);
4516 return page != NULL;
4519 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4522 struct inode *inode = mapping->host;
4523 struct hstate *h = hstate_inode(inode);
4524 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4528 ClearHPageRestoreReserve(page);
4531 * set page dirty so that it will not be removed from cache/file
4532 * by non-hugetlbfs specific code paths.
4534 set_page_dirty(page);
4536 spin_lock(&inode->i_lock);
4537 inode->i_blocks += blocks_per_huge_page(h);
4538 spin_unlock(&inode->i_lock);
4542 static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
4543 struct address_space *mapping,
4546 unsigned long haddr,
4547 unsigned long reason)
4551 struct vm_fault vmf = {
4557 * Hard to debug if it ends up being
4558 * used by a callee that assumes
4559 * something about the other
4560 * uninitialized fields... same as in
4566 * hugetlb_fault_mutex and i_mmap_rwsem must be
4567 * dropped before handling userfault. Reacquire
4568 * after handling fault to make calling code simpler.
4570 hash = hugetlb_fault_mutex_hash(mapping, idx);
4571 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4572 i_mmap_unlock_read(mapping);
4573 ret = handle_userfault(&vmf, reason);
4574 i_mmap_lock_read(mapping);
4575 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4580 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4581 struct vm_area_struct *vma,
4582 struct address_space *mapping, pgoff_t idx,
4583 unsigned long address, pte_t *ptep, unsigned int flags)
4585 struct hstate *h = hstate_vma(vma);
4586 vm_fault_t ret = VM_FAULT_SIGBUS;
4592 unsigned long haddr = address & huge_page_mask(h);
4593 bool new_page = false;
4596 * Currently, we are forced to kill the process in the event the
4597 * original mapper has unmapped pages from the child due to a failed
4598 * COW. Warn that such a situation has occurred as it may not be obvious
4600 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4601 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4607 * We can not race with truncation due to holding i_mmap_rwsem.
4608 * i_size is modified when holding i_mmap_rwsem, so check here
4609 * once for faults beyond end of file.
4611 size = i_size_read(mapping->host) >> huge_page_shift(h);
4616 page = find_lock_page(mapping, idx);
4618 /* Check for page in userfault range */
4619 if (userfaultfd_missing(vma)) {
4620 ret = hugetlb_handle_userfault(vma, mapping, idx,
4626 page = alloc_huge_page(vma, haddr, 0);
4629 * Returning error will result in faulting task being
4630 * sent SIGBUS. The hugetlb fault mutex prevents two
4631 * tasks from racing to fault in the same page which
4632 * could result in false unable to allocate errors.
4633 * Page migration does not take the fault mutex, but
4634 * does a clear then write of pte's under page table
4635 * lock. Page fault code could race with migration,
4636 * notice the clear pte and try to allocate a page
4637 * here. Before returning error, get ptl and make
4638 * sure there really is no pte entry.
4640 ptl = huge_pte_lock(h, mm, ptep);
4642 if (huge_pte_none(huge_ptep_get(ptep)))
4643 ret = vmf_error(PTR_ERR(page));
4647 clear_huge_page(page, address, pages_per_huge_page(h));
4648 __SetPageUptodate(page);
4651 if (vma->vm_flags & VM_MAYSHARE) {
4652 int err = huge_add_to_page_cache(page, mapping, idx);
4661 if (unlikely(anon_vma_prepare(vma))) {
4663 goto backout_unlocked;
4669 * If memory error occurs between mmap() and fault, some process
4670 * don't have hwpoisoned swap entry for errored virtual address.
4671 * So we need to block hugepage fault by PG_hwpoison bit check.
4673 if (unlikely(PageHWPoison(page))) {
4674 ret = VM_FAULT_HWPOISON_LARGE |
4675 VM_FAULT_SET_HINDEX(hstate_index(h));
4676 goto backout_unlocked;
4679 /* Check for page in userfault range. */
4680 if (userfaultfd_minor(vma)) {
4683 ret = hugetlb_handle_userfault(vma, mapping, idx,
4691 * If we are going to COW a private mapping later, we examine the
4692 * pending reservations for this page now. This will ensure that
4693 * any allocations necessary to record that reservation occur outside
4696 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4697 if (vma_needs_reservation(h, vma, haddr) < 0) {
4699 goto backout_unlocked;
4701 /* Just decrements count, does not deallocate */
4702 vma_end_reservation(h, vma, haddr);
4705 ptl = huge_pte_lock(h, mm, ptep);
4707 if (!huge_pte_none(huge_ptep_get(ptep)))
4711 ClearHPageRestoreReserve(page);
4712 hugepage_add_new_anon_rmap(page, vma, haddr);
4714 page_dup_rmap(page, true);
4715 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4716 && (vma->vm_flags & VM_SHARED)));
4717 set_huge_pte_at(mm, haddr, ptep, new_pte);
4719 hugetlb_count_add(pages_per_huge_page(h), mm);
4720 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4721 /* Optimization, do the COW without a second fault */
4722 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4728 * Only set HPageMigratable in newly allocated pages. Existing pages
4729 * found in the pagecache may not have HPageMigratableset if they have
4730 * been isolated for migration.
4733 SetHPageMigratable(page);
4743 restore_reserve_on_error(h, vma, haddr, page);
4749 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4751 unsigned long key[2];
4754 key[0] = (unsigned long) mapping;
4757 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4759 return hash & (num_fault_mutexes - 1);
4763 * For uniprocessor systems we always use a single mutex, so just
4764 * return 0 and avoid the hashing overhead.
4766 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4772 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4773 unsigned long address, unsigned int flags)
4780 struct page *page = NULL;
4781 struct page *pagecache_page = NULL;
4782 struct hstate *h = hstate_vma(vma);
4783 struct address_space *mapping;
4784 int need_wait_lock = 0;
4785 unsigned long haddr = address & huge_page_mask(h);
4787 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4790 * Since we hold no locks, ptep could be stale. That is
4791 * OK as we are only making decisions based on content and
4792 * not actually modifying content here.
4794 entry = huge_ptep_get(ptep);
4795 if (unlikely(is_hugetlb_entry_migration(entry))) {
4796 migration_entry_wait_huge(vma, mm, ptep);
4798 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4799 return VM_FAULT_HWPOISON_LARGE |
4800 VM_FAULT_SET_HINDEX(hstate_index(h));
4804 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4805 * until finished with ptep. This serves two purposes:
4806 * 1) It prevents huge_pmd_unshare from being called elsewhere
4807 * and making the ptep no longer valid.
4808 * 2) It synchronizes us with i_size modifications during truncation.
4810 * ptep could have already be assigned via huge_pte_offset. That
4811 * is OK, as huge_pte_alloc will return the same value unless
4812 * something has changed.
4814 mapping = vma->vm_file->f_mapping;
4815 i_mmap_lock_read(mapping);
4816 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
4818 i_mmap_unlock_read(mapping);
4819 return VM_FAULT_OOM;
4823 * Serialize hugepage allocation and instantiation, so that we don't
4824 * get spurious allocation failures if two CPUs race to instantiate
4825 * the same page in the page cache.
4827 idx = vma_hugecache_offset(h, vma, haddr);
4828 hash = hugetlb_fault_mutex_hash(mapping, idx);
4829 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4831 entry = huge_ptep_get(ptep);
4832 if (huge_pte_none(entry)) {
4833 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4840 * entry could be a migration/hwpoison entry at this point, so this
4841 * check prevents the kernel from going below assuming that we have
4842 * an active hugepage in pagecache. This goto expects the 2nd page
4843 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4844 * properly handle it.
4846 if (!pte_present(entry))
4850 * If we are going to COW the mapping later, we examine the pending
4851 * reservations for this page now. This will ensure that any
4852 * allocations necessary to record that reservation occur outside the
4853 * spinlock. For private mappings, we also lookup the pagecache
4854 * page now as it is used to determine if a reservation has been
4857 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4858 if (vma_needs_reservation(h, vma, haddr) < 0) {
4862 /* Just decrements count, does not deallocate */
4863 vma_end_reservation(h, vma, haddr);
4865 if (!(vma->vm_flags & VM_MAYSHARE))
4866 pagecache_page = hugetlbfs_pagecache_page(h,
4870 ptl = huge_pte_lock(h, mm, ptep);
4872 /* Check for a racing update before calling hugetlb_cow */
4873 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4877 * hugetlb_cow() requires page locks of pte_page(entry) and
4878 * pagecache_page, so here we need take the former one
4879 * when page != pagecache_page or !pagecache_page.
4881 page = pte_page(entry);
4882 if (page != pagecache_page)
4883 if (!trylock_page(page)) {
4890 if (flags & FAULT_FLAG_WRITE) {
4891 if (!huge_pte_write(entry)) {
4892 ret = hugetlb_cow(mm, vma, address, ptep,
4893 pagecache_page, ptl);
4896 entry = huge_pte_mkdirty(entry);
4898 entry = pte_mkyoung(entry);
4899 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4900 flags & FAULT_FLAG_WRITE))
4901 update_mmu_cache(vma, haddr, ptep);
4903 if (page != pagecache_page)
4909 if (pagecache_page) {
4910 unlock_page(pagecache_page);
4911 put_page(pagecache_page);
4914 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4915 i_mmap_unlock_read(mapping);
4917 * Generally it's safe to hold refcount during waiting page lock. But
4918 * here we just wait to defer the next page fault to avoid busy loop and
4919 * the page is not used after unlocked before returning from the current
4920 * page fault. So we are safe from accessing freed page, even if we wait
4921 * here without taking refcount.
4924 wait_on_page_locked(page);
4928 #ifdef CONFIG_USERFAULTFD
4930 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4931 * modifications for huge pages.
4933 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4935 struct vm_area_struct *dst_vma,
4936 unsigned long dst_addr,
4937 unsigned long src_addr,
4938 enum mcopy_atomic_mode mode,
4939 struct page **pagep)
4941 bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
4942 struct address_space *mapping;
4945 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4946 struct hstate *h = hstate_vma(dst_vma);
4953 mapping = dst_vma->vm_file->f_mapping;
4954 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4958 page = find_lock_page(mapping, idx);
4961 } else if (!*pagep) {
4962 /* If a page already exists, then it's UFFDIO_COPY for
4963 * a non-missing case. Return -EEXIST.
4966 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
4971 page = alloc_huge_page(dst_vma, dst_addr, 0);
4977 ret = copy_huge_page_from_user(page,
4978 (const void __user *) src_addr,
4979 pages_per_huge_page(h), false);
4981 /* fallback to copy_from_user outside mmap_lock */
4982 if (unlikely(ret)) {
4985 /* don't free the page */
4994 * The memory barrier inside __SetPageUptodate makes sure that
4995 * preceding stores to the page contents become visible before
4996 * the set_pte_at() write.
4998 __SetPageUptodate(page);
5000 /* Add shared, newly allocated pages to the page cache. */
5001 if (vm_shared && !is_continue) {
5002 size = i_size_read(mapping->host) >> huge_page_shift(h);
5005 goto out_release_nounlock;
5008 * Serialization between remove_inode_hugepages() and
5009 * huge_add_to_page_cache() below happens through the
5010 * hugetlb_fault_mutex_table that here must be hold by
5013 ret = huge_add_to_page_cache(page, mapping, idx);
5015 goto out_release_nounlock;
5018 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
5022 * Recheck the i_size after holding PT lock to make sure not
5023 * to leave any page mapped (as page_mapped()) beyond the end
5024 * of the i_size (remove_inode_hugepages() is strict about
5025 * enforcing that). If we bail out here, we'll also leave a
5026 * page in the radix tree in the vm_shared case beyond the end
5027 * of the i_size, but remove_inode_hugepages() will take care
5028 * of it as soon as we drop the hugetlb_fault_mutex_table.
5030 size = i_size_read(mapping->host) >> huge_page_shift(h);
5033 goto out_release_unlock;
5036 if (!huge_pte_none(huge_ptep_get(dst_pte)))
5037 goto out_release_unlock;
5040 page_dup_rmap(page, true);
5042 ClearHPageRestoreReserve(page);
5043 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
5046 /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
5047 if (is_continue && !vm_shared)
5050 writable = dst_vma->vm_flags & VM_WRITE;
5052 _dst_pte = make_huge_pte(dst_vma, page, writable);
5054 _dst_pte = huge_pte_mkdirty(_dst_pte);
5055 _dst_pte = pte_mkyoung(_dst_pte);
5057 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
5059 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
5060 dst_vma->vm_flags & VM_WRITE);
5061 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
5063 /* No need to invalidate - it was non-present before */
5064 update_mmu_cache(dst_vma, dst_addr, dst_pte);
5068 SetHPageMigratable(page);
5069 if (vm_shared || is_continue)
5076 if (vm_shared || is_continue)
5078 out_release_nounlock:
5079 restore_reserve_on_error(h, dst_vma, dst_addr, page);
5083 #endif /* CONFIG_USERFAULTFD */
5085 static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
5086 int refs, struct page **pages,
5087 struct vm_area_struct **vmas)
5091 for (nr = 0; nr < refs; nr++) {
5093 pages[nr] = mem_map_offset(page, nr);
5099 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
5100 struct page **pages, struct vm_area_struct **vmas,
5101 unsigned long *position, unsigned long *nr_pages,
5102 long i, unsigned int flags, int *locked)
5104 unsigned long pfn_offset;
5105 unsigned long vaddr = *position;
5106 unsigned long remainder = *nr_pages;
5107 struct hstate *h = hstate_vma(vma);
5108 int err = -EFAULT, refs;
5110 while (vaddr < vma->vm_end && remainder) {
5112 spinlock_t *ptl = NULL;
5117 * If we have a pending SIGKILL, don't keep faulting pages and
5118 * potentially allocating memory.
5120 if (fatal_signal_pending(current)) {
5126 * Some archs (sparc64, sh*) have multiple pte_ts to
5127 * each hugepage. We have to make sure we get the
5128 * first, for the page indexing below to work.
5130 * Note that page table lock is not held when pte is null.
5132 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
5135 ptl = huge_pte_lock(h, mm, pte);
5136 absent = !pte || huge_pte_none(huge_ptep_get(pte));
5139 * When coredumping, it suits get_dump_page if we just return
5140 * an error where there's an empty slot with no huge pagecache
5141 * to back it. This way, we avoid allocating a hugepage, and
5142 * the sparse dumpfile avoids allocating disk blocks, but its
5143 * huge holes still show up with zeroes where they need to be.
5145 if (absent && (flags & FOLL_DUMP) &&
5146 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
5154 * We need call hugetlb_fault for both hugepages under migration
5155 * (in which case hugetlb_fault waits for the migration,) and
5156 * hwpoisoned hugepages (in which case we need to prevent the
5157 * caller from accessing to them.) In order to do this, we use
5158 * here is_swap_pte instead of is_hugetlb_entry_migration and
5159 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
5160 * both cases, and because we can't follow correct pages
5161 * directly from any kind of swap entries.
5163 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
5164 ((flags & FOLL_WRITE) &&
5165 !huge_pte_write(huge_ptep_get(pte)))) {
5167 unsigned int fault_flags = 0;
5171 if (flags & FOLL_WRITE)
5172 fault_flags |= FAULT_FLAG_WRITE;
5174 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5175 FAULT_FLAG_KILLABLE;
5176 if (flags & FOLL_NOWAIT)
5177 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5178 FAULT_FLAG_RETRY_NOWAIT;
5179 if (flags & FOLL_TRIED) {
5181 * Note: FAULT_FLAG_ALLOW_RETRY and
5182 * FAULT_FLAG_TRIED can co-exist
5184 fault_flags |= FAULT_FLAG_TRIED;
5186 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
5187 if (ret & VM_FAULT_ERROR) {
5188 err = vm_fault_to_errno(ret, flags);
5192 if (ret & VM_FAULT_RETRY) {
5194 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
5198 * VM_FAULT_RETRY must not return an
5199 * error, it will return zero
5202 * No need to update "position" as the
5203 * caller will not check it after
5204 * *nr_pages is set to 0.
5211 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
5212 page = pte_page(huge_ptep_get(pte));
5215 * If subpage information not requested, update counters
5216 * and skip the same_page loop below.
5218 if (!pages && !vmas && !pfn_offset &&
5219 (vaddr + huge_page_size(h) < vma->vm_end) &&
5220 (remainder >= pages_per_huge_page(h))) {
5221 vaddr += huge_page_size(h);
5222 remainder -= pages_per_huge_page(h);
5223 i += pages_per_huge_page(h);
5228 refs = min3(pages_per_huge_page(h) - pfn_offset,
5229 (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
5232 record_subpages_vmas(mem_map_offset(page, pfn_offset),
5234 likely(pages) ? pages + i : NULL,
5235 vmas ? vmas + i : NULL);
5239 * try_grab_compound_head() should always succeed here,
5240 * because: a) we hold the ptl lock, and b) we've just
5241 * checked that the huge page is present in the page
5242 * tables. If the huge page is present, then the tail
5243 * pages must also be present. The ptl prevents the
5244 * head page and tail pages from being rearranged in
5245 * any way. So this page must be available at this
5246 * point, unless the page refcount overflowed:
5248 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
5258 vaddr += (refs << PAGE_SHIFT);
5264 *nr_pages = remainder;
5266 * setting position is actually required only if remainder is
5267 * not zero but it's faster not to add a "if (remainder)"
5275 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5276 unsigned long address, unsigned long end, pgprot_t newprot)
5278 struct mm_struct *mm = vma->vm_mm;
5279 unsigned long start = address;
5282 struct hstate *h = hstate_vma(vma);
5283 unsigned long pages = 0;
5284 bool shared_pmd = false;
5285 struct mmu_notifier_range range;
5288 * In the case of shared PMDs, the area to flush could be beyond
5289 * start/end. Set range.start/range.end to cover the maximum possible
5290 * range if PMD sharing is possible.
5292 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5293 0, vma, mm, start, end);
5294 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5296 BUG_ON(address >= end);
5297 flush_cache_range(vma, range.start, range.end);
5299 mmu_notifier_invalidate_range_start(&range);
5300 i_mmap_lock_write(vma->vm_file->f_mapping);
5301 for (; address < end; address += huge_page_size(h)) {
5303 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5306 ptl = huge_pte_lock(h, mm, ptep);
5307 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5313 pte = huge_ptep_get(ptep);
5314 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5318 if (unlikely(is_hugetlb_entry_migration(pte))) {
5319 swp_entry_t entry = pte_to_swp_entry(pte);
5321 if (is_write_migration_entry(entry)) {
5324 make_migration_entry_read(&entry);
5325 newpte = swp_entry_to_pte(entry);
5326 set_huge_swap_pte_at(mm, address, ptep,
5327 newpte, huge_page_size(h));
5333 if (!huge_pte_none(pte)) {
5336 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5337 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5338 pte = arch_make_huge_pte(pte, vma, NULL, 0);
5339 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5345 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5346 * may have cleared our pud entry and done put_page on the page table:
5347 * once we release i_mmap_rwsem, another task can do the final put_page
5348 * and that page table be reused and filled with junk. If we actually
5349 * did unshare a page of pmds, flush the range corresponding to the pud.
5352 flush_hugetlb_tlb_range(vma, range.start, range.end);
5354 flush_hugetlb_tlb_range(vma, start, end);
5356 * No need to call mmu_notifier_invalidate_range() we are downgrading
5357 * page table protection not changing it to point to a new page.
5359 * See Documentation/vm/mmu_notifier.rst
5361 i_mmap_unlock_write(vma->vm_file->f_mapping);
5362 mmu_notifier_invalidate_range_end(&range);
5364 return pages << h->order;
5367 /* Return true if reservation was successful, false otherwise. */
5368 bool hugetlb_reserve_pages(struct inode *inode,
5370 struct vm_area_struct *vma,
5371 vm_flags_t vm_flags)
5374 struct hstate *h = hstate_inode(inode);
5375 struct hugepage_subpool *spool = subpool_inode(inode);
5376 struct resv_map *resv_map;
5377 struct hugetlb_cgroup *h_cg = NULL;
5378 long gbl_reserve, regions_needed = 0;
5380 /* This should never happen */
5382 VM_WARN(1, "%s called with a negative range\n", __func__);
5387 * Only apply hugepage reservation if asked. At fault time, an
5388 * attempt will be made for VM_NORESERVE to allocate a page
5389 * without using reserves
5391 if (vm_flags & VM_NORESERVE)
5395 * Shared mappings base their reservation on the number of pages that
5396 * are already allocated on behalf of the file. Private mappings need
5397 * to reserve the full area even if read-only as mprotect() may be
5398 * called to make the mapping read-write. Assume !vma is a shm mapping
5400 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5402 * resv_map can not be NULL as hugetlb_reserve_pages is only
5403 * called for inodes for which resv_maps were created (see
5404 * hugetlbfs_get_inode).
5406 resv_map = inode_resv_map(inode);
5408 chg = region_chg(resv_map, from, to, ®ions_needed);
5411 /* Private mapping. */
5412 resv_map = resv_map_alloc();
5418 set_vma_resv_map(vma, resv_map);
5419 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5425 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
5426 chg * pages_per_huge_page(h), &h_cg) < 0)
5429 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5430 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5433 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5437 * There must be enough pages in the subpool for the mapping. If
5438 * the subpool has a minimum size, there may be some global
5439 * reservations already in place (gbl_reserve).
5441 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5442 if (gbl_reserve < 0)
5443 goto out_uncharge_cgroup;
5446 * Check enough hugepages are available for the reservation.
5447 * Hand the pages back to the subpool if there are not
5449 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
5453 * Account for the reservations made. Shared mappings record regions
5454 * that have reservations as they are shared by multiple VMAs.
5455 * When the last VMA disappears, the region map says how much
5456 * the reservation was and the page cache tells how much of
5457 * the reservation was consumed. Private mappings are per-VMA and
5458 * only the consumed reservations are tracked. When the VMA
5459 * disappears, the original reservation is the VMA size and the
5460 * consumed reservations are stored in the map. Hence, nothing
5461 * else has to be done for private mappings here
5463 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5464 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5466 if (unlikely(add < 0)) {
5467 hugetlb_acct_memory(h, -gbl_reserve);
5469 } else if (unlikely(chg > add)) {
5471 * pages in this range were added to the reserve
5472 * map between region_chg and region_add. This
5473 * indicates a race with alloc_huge_page. Adjust
5474 * the subpool and reserve counts modified above
5475 * based on the difference.
5480 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5481 * reference to h_cg->css. See comment below for detail.
5483 hugetlb_cgroup_uncharge_cgroup_rsvd(
5485 (chg - add) * pages_per_huge_page(h), h_cg);
5487 rsv_adjust = hugepage_subpool_put_pages(spool,
5489 hugetlb_acct_memory(h, -rsv_adjust);
5492 * The file_regions will hold their own reference to
5493 * h_cg->css. So we should release the reference held
5494 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5497 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5503 /* put back original number of pages, chg */
5504 (void)hugepage_subpool_put_pages(spool, chg);
5505 out_uncharge_cgroup:
5506 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5507 chg * pages_per_huge_page(h), h_cg);
5509 if (!vma || vma->vm_flags & VM_MAYSHARE)
5510 /* Only call region_abort if the region_chg succeeded but the
5511 * region_add failed or didn't run.
5513 if (chg >= 0 && add < 0)
5514 region_abort(resv_map, from, to, regions_needed);
5515 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5516 kref_put(&resv_map->refs, resv_map_release);
5520 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5523 struct hstate *h = hstate_inode(inode);
5524 struct resv_map *resv_map = inode_resv_map(inode);
5526 struct hugepage_subpool *spool = subpool_inode(inode);
5530 * Since this routine can be called in the evict inode path for all
5531 * hugetlbfs inodes, resv_map could be NULL.
5534 chg = region_del(resv_map, start, end);
5536 * region_del() can fail in the rare case where a region
5537 * must be split and another region descriptor can not be
5538 * allocated. If end == LONG_MAX, it will not fail.
5544 spin_lock(&inode->i_lock);
5545 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5546 spin_unlock(&inode->i_lock);
5549 * If the subpool has a minimum size, the number of global
5550 * reservations to be released may be adjusted.
5552 * Note that !resv_map implies freed == 0. So (chg - freed)
5553 * won't go negative.
5555 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5556 hugetlb_acct_memory(h, -gbl_reserve);
5561 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5562 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5563 struct vm_area_struct *vma,
5564 unsigned long addr, pgoff_t idx)
5566 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5568 unsigned long sbase = saddr & PUD_MASK;
5569 unsigned long s_end = sbase + PUD_SIZE;
5571 /* Allow segments to share if only one is marked locked */
5572 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5573 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5576 * match the virtual addresses, permission and the alignment of the
5579 if (pmd_index(addr) != pmd_index(saddr) ||
5580 vm_flags != svm_flags ||
5581 !range_in_vma(svma, sbase, s_end))
5587 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5589 unsigned long base = addr & PUD_MASK;
5590 unsigned long end = base + PUD_SIZE;
5593 * check on proper vm_flags and page table alignment
5595 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5600 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5602 #ifdef CONFIG_USERFAULTFD
5603 if (uffd_disable_huge_pmd_share(vma))
5606 return vma_shareable(vma, addr);
5610 * Determine if start,end range within vma could be mapped by shared pmd.
5611 * If yes, adjust start and end to cover range associated with possible
5612 * shared pmd mappings.
5614 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5615 unsigned long *start, unsigned long *end)
5617 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5618 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5621 * vma needs to span at least one aligned PUD size, and the range
5622 * must be at least partially within in.
5624 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5625 (*end <= v_start) || (*start >= v_end))
5628 /* Extend the range to be PUD aligned for a worst case scenario */
5629 if (*start > v_start)
5630 *start = ALIGN_DOWN(*start, PUD_SIZE);
5633 *end = ALIGN(*end, PUD_SIZE);
5637 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5638 * and returns the corresponding pte. While this is not necessary for the
5639 * !shared pmd case because we can allocate the pmd later as well, it makes the
5640 * code much cleaner.
5642 * This routine must be called with i_mmap_rwsem held in at least read mode if
5643 * sharing is possible. For hugetlbfs, this prevents removal of any page
5644 * table entries associated with the address space. This is important as we
5645 * are setting up sharing based on existing page table entries (mappings).
5647 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5648 * huge_pte_alloc know that sharing is not possible and do not take
5649 * i_mmap_rwsem as a performance optimization. This is handled by the
5650 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5651 * only required for subsequent processing.
5653 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5654 unsigned long addr, pud_t *pud)
5656 struct address_space *mapping = vma->vm_file->f_mapping;
5657 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5659 struct vm_area_struct *svma;
5660 unsigned long saddr;
5665 i_mmap_assert_locked(mapping);
5666 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5670 saddr = page_table_shareable(svma, vma, addr, idx);
5672 spte = huge_pte_offset(svma->vm_mm, saddr,
5673 vma_mmu_pagesize(svma));
5675 get_page(virt_to_page(spte));
5684 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5685 if (pud_none(*pud)) {
5686 pud_populate(mm, pud,
5687 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5690 put_page(virt_to_page(spte));
5694 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5699 * unmap huge page backed by shared pte.
5701 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5702 * indicated by page_count > 1, unmap is achieved by clearing pud and
5703 * decrementing the ref count. If count == 1, the pte page is not shared.
5705 * Called with page table lock held and i_mmap_rwsem held in write mode.
5707 * returns: 1 successfully unmapped a shared pte page
5708 * 0 the underlying pte page is not shared, or it is the last user
5710 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5711 unsigned long *addr, pte_t *ptep)
5713 pgd_t *pgd = pgd_offset(mm, *addr);
5714 p4d_t *p4d = p4d_offset(pgd, *addr);
5715 pud_t *pud = pud_offset(p4d, *addr);
5717 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5718 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5719 if (page_count(virt_to_page(ptep)) == 1)
5723 put_page(virt_to_page(ptep));
5725 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5729 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5730 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5731 unsigned long addr, pud_t *pud)
5736 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5737 unsigned long *addr, pte_t *ptep)
5742 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5743 unsigned long *start, unsigned long *end)
5747 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5751 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5753 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5754 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
5755 unsigned long addr, unsigned long sz)
5762 pgd = pgd_offset(mm, addr);
5763 p4d = p4d_alloc(mm, pgd, addr);
5766 pud = pud_alloc(mm, p4d, addr);
5768 if (sz == PUD_SIZE) {
5771 BUG_ON(sz != PMD_SIZE);
5772 if (want_pmd_share(vma, addr) && pud_none(*pud))
5773 pte = huge_pmd_share(mm, vma, addr, pud);
5775 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5778 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5784 * huge_pte_offset() - Walk the page table to resolve the hugepage
5785 * entry at address @addr
5787 * Return: Pointer to page table entry (PUD or PMD) for
5788 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5789 * size @sz doesn't match the hugepage size at this level of the page
5792 pte_t *huge_pte_offset(struct mm_struct *mm,
5793 unsigned long addr, unsigned long sz)
5800 pgd = pgd_offset(mm, addr);
5801 if (!pgd_present(*pgd))
5803 p4d = p4d_offset(pgd, addr);
5804 if (!p4d_present(*p4d))
5807 pud = pud_offset(p4d, addr);
5809 /* must be pud huge, non-present or none */
5810 return (pte_t *)pud;
5811 if (!pud_present(*pud))
5813 /* must have a valid entry and size to go further */
5815 pmd = pmd_offset(pud, addr);
5816 /* must be pmd huge, non-present or none */
5817 return (pte_t *)pmd;
5820 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5823 * These functions are overwritable if your architecture needs its own
5826 struct page * __weak
5827 follow_huge_addr(struct mm_struct *mm, unsigned long address,
5830 return ERR_PTR(-EINVAL);
5833 struct page * __weak
5834 follow_huge_pd(struct vm_area_struct *vma,
5835 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5837 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5841 struct page * __weak
5842 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5843 pmd_t *pmd, int flags)
5845 struct page *page = NULL;
5849 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5850 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5851 (FOLL_PIN | FOLL_GET)))
5855 ptl = pmd_lockptr(mm, pmd);
5858 * make sure that the address range covered by this pmd is not
5859 * unmapped from other threads.
5861 if (!pmd_huge(*pmd))
5863 pte = huge_ptep_get((pte_t *)pmd);
5864 if (pte_present(pte)) {
5865 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5867 * try_grab_page() should always succeed here, because: a) we
5868 * hold the pmd (ptl) lock, and b) we've just checked that the
5869 * huge pmd (head) page is present in the page tables. The ptl
5870 * prevents the head page and tail pages from being rearranged
5871 * in any way. So this page must be available at this point,
5872 * unless the page refcount overflowed:
5874 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5879 if (is_hugetlb_entry_migration(pte)) {
5881 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5885 * hwpoisoned entry is treated as no_page_table in
5886 * follow_page_mask().
5894 struct page * __weak
5895 follow_huge_pud(struct mm_struct *mm, unsigned long address,
5896 pud_t *pud, int flags)
5898 if (flags & (FOLL_GET | FOLL_PIN))
5901 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5904 struct page * __weak
5905 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5907 if (flags & (FOLL_GET | FOLL_PIN))
5910 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5913 bool isolate_huge_page(struct page *page, struct list_head *list)
5917 spin_lock_irq(&hugetlb_lock);
5918 if (!PageHeadHuge(page) ||
5919 !HPageMigratable(page) ||
5920 !get_page_unless_zero(page)) {
5924 ClearHPageMigratable(page);
5925 list_move_tail(&page->lru, list);
5927 spin_unlock_irq(&hugetlb_lock);
5931 int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
5936 spin_lock_irq(&hugetlb_lock);
5937 if (PageHeadHuge(page)) {
5939 if (HPageFreed(page) || HPageMigratable(page))
5940 ret = get_page_unless_zero(page);
5944 spin_unlock_irq(&hugetlb_lock);
5948 void putback_active_hugepage(struct page *page)
5950 spin_lock_irq(&hugetlb_lock);
5951 SetHPageMigratable(page);
5952 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5953 spin_unlock_irq(&hugetlb_lock);
5957 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5959 struct hstate *h = page_hstate(oldpage);
5961 hugetlb_cgroup_migrate(oldpage, newpage);
5962 set_page_owner_migrate_reason(newpage, reason);
5965 * transfer temporary state of the new huge page. This is
5966 * reverse to other transitions because the newpage is going to
5967 * be final while the old one will be freed so it takes over
5968 * the temporary status.
5970 * Also note that we have to transfer the per-node surplus state
5971 * here as well otherwise the global surplus count will not match
5974 if (HPageTemporary(newpage)) {
5975 int old_nid = page_to_nid(oldpage);
5976 int new_nid = page_to_nid(newpage);
5978 SetHPageTemporary(oldpage);
5979 ClearHPageTemporary(newpage);
5982 * There is no need to transfer the per-node surplus state
5983 * when we do not cross the node.
5985 if (new_nid == old_nid)
5987 spin_lock_irq(&hugetlb_lock);
5988 if (h->surplus_huge_pages_node[old_nid]) {
5989 h->surplus_huge_pages_node[old_nid]--;
5990 h->surplus_huge_pages_node[new_nid]++;
5992 spin_unlock_irq(&hugetlb_lock);
5997 * This function will unconditionally remove all the shared pmd pgtable entries
5998 * within the specific vma for a hugetlbfs memory range.
6000 void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
6002 struct hstate *h = hstate_vma(vma);
6003 unsigned long sz = huge_page_size(h);
6004 struct mm_struct *mm = vma->vm_mm;
6005 struct mmu_notifier_range range;
6006 unsigned long address, start, end;
6010 if (!(vma->vm_flags & VM_MAYSHARE))
6013 start = ALIGN(vma->vm_start, PUD_SIZE);
6014 end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
6020 * No need to call adjust_range_if_pmd_sharing_possible(), because
6021 * we have already done the PUD_SIZE alignment.
6023 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
6025 mmu_notifier_invalidate_range_start(&range);
6026 i_mmap_lock_write(vma->vm_file->f_mapping);
6027 for (address = start; address < end; address += PUD_SIZE) {
6028 unsigned long tmp = address;
6030 ptep = huge_pte_offset(mm, address, sz);
6033 ptl = huge_pte_lock(h, mm, ptep);
6034 /* We don't want 'address' to be changed */
6035 huge_pmd_unshare(mm, vma, &tmp, ptep);
6038 flush_hugetlb_tlb_range(vma, start, end);
6039 i_mmap_unlock_write(vma->vm_file->f_mapping);
6041 * No need to call mmu_notifier_invalidate_range(), see
6042 * Documentation/vm/mmu_notifier.rst.
6044 mmu_notifier_invalidate_range_end(&range);
6048 static bool cma_reserve_called __initdata;
6050 static int __init cmdline_parse_hugetlb_cma(char *p)
6052 hugetlb_cma_size = memparse(p, &p);
6056 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
6058 void __init hugetlb_cma_reserve(int order)
6060 unsigned long size, reserved, per_node;
6063 cma_reserve_called = true;
6065 if (!hugetlb_cma_size)
6068 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
6069 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
6070 (PAGE_SIZE << order) / SZ_1M);
6075 * If 3 GB area is requested on a machine with 4 numa nodes,
6076 * let's allocate 1 GB on first three nodes and ignore the last one.
6078 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
6079 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
6080 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
6083 for_each_node_state(nid, N_ONLINE) {
6085 char name[CMA_MAX_NAME];
6087 size = min(per_node, hugetlb_cma_size - reserved);
6088 size = round_up(size, PAGE_SIZE << order);
6090 snprintf(name, sizeof(name), "hugetlb%d", nid);
6091 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
6093 &hugetlb_cma[nid], nid);
6095 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
6101 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
6104 if (reserved >= hugetlb_cma_size)
6109 void __init hugetlb_cma_check(void)
6111 if (!hugetlb_cma_size || cma_reserve_called)
6114 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
6117 #endif /* CONFIG_CMA */