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 existings 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 __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 (!PageHuge(page_head))
1598 return page_index(page);
1600 if (compound_order(page_head) >= MAX_ORDER)
1601 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1603 compound_idx = page - page_head;
1605 return (index << compound_order(page_head)) + compound_idx;
1608 static struct page *alloc_buddy_huge_page(struct hstate *h,
1609 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1610 nodemask_t *node_alloc_noretry)
1612 int order = huge_page_order(h);
1614 bool alloc_try_hard = true;
1617 * By default we always try hard to allocate the page with
1618 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1619 * a loop (to adjust global huge page counts) and previous allocation
1620 * failed, do not continue to try hard on the same node. Use the
1621 * node_alloc_noretry bitmap to manage this state information.
1623 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1624 alloc_try_hard = false;
1625 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1627 gfp_mask |= __GFP_RETRY_MAYFAIL;
1628 if (nid == NUMA_NO_NODE)
1629 nid = numa_mem_id();
1630 page = __alloc_pages(gfp_mask, order, nid, nmask);
1632 __count_vm_event(HTLB_BUDDY_PGALLOC);
1634 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1637 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1638 * indicates an overall state change. Clear bit so that we resume
1639 * normal 'try hard' allocations.
1641 if (node_alloc_noretry && page && !alloc_try_hard)
1642 node_clear(nid, *node_alloc_noretry);
1645 * If we tried hard to get a page but failed, set bit so that
1646 * subsequent attempts will not try as hard until there is an
1647 * overall state change.
1649 if (node_alloc_noretry && !page && alloc_try_hard)
1650 node_set(nid, *node_alloc_noretry);
1656 * Common helper to allocate a fresh hugetlb page. All specific allocators
1657 * should use this function to get new hugetlb pages
1659 static struct page *alloc_fresh_huge_page(struct hstate *h,
1660 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1661 nodemask_t *node_alloc_noretry)
1665 if (hstate_is_gigantic(h))
1666 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1668 page = alloc_buddy_huge_page(h, gfp_mask,
1669 nid, nmask, node_alloc_noretry);
1673 if (hstate_is_gigantic(h))
1674 prep_compound_gigantic_page(page, huge_page_order(h));
1675 prep_new_huge_page(h, page, page_to_nid(page));
1681 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1684 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1685 nodemask_t *node_alloc_noretry)
1689 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1691 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1692 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1693 node_alloc_noretry);
1701 put_page(page); /* free it into the hugepage allocator */
1707 * Remove huge page from pool from next node to free. Attempt to keep
1708 * persistent huge pages more or less balanced over allowed nodes.
1709 * This routine only 'removes' the hugetlb page. The caller must make
1710 * an additional call to free the page to low level allocators.
1711 * Called with hugetlb_lock locked.
1713 static struct page *remove_pool_huge_page(struct hstate *h,
1714 nodemask_t *nodes_allowed,
1718 struct page *page = NULL;
1720 lockdep_assert_held(&hugetlb_lock);
1721 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1723 * If we're returning unused surplus pages, only examine
1724 * nodes with surplus pages.
1726 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1727 !list_empty(&h->hugepage_freelists[node])) {
1728 page = list_entry(h->hugepage_freelists[node].next,
1730 remove_hugetlb_page(h, page, acct_surplus);
1739 * Dissolve a given free hugepage into free buddy pages. This function does
1740 * nothing for in-use hugepages and non-hugepages.
1741 * This function returns values like below:
1743 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1744 * (allocated or reserved.)
1745 * 0: successfully dissolved free hugepages or the page is not a
1746 * hugepage (considered as already dissolved)
1748 int dissolve_free_huge_page(struct page *page)
1753 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1754 if (!PageHuge(page))
1757 spin_lock_irq(&hugetlb_lock);
1758 if (!PageHuge(page)) {
1763 if (!page_count(page)) {
1764 struct page *head = compound_head(page);
1765 struct hstate *h = page_hstate(head);
1766 if (h->free_huge_pages - h->resv_huge_pages == 0)
1770 * We should make sure that the page is already on the free list
1771 * when it is dissolved.
1773 if (unlikely(!HPageFreed(head))) {
1774 spin_unlock_irq(&hugetlb_lock);
1778 * Theoretically, we should return -EBUSY when we
1779 * encounter this race. In fact, we have a chance
1780 * to successfully dissolve the page if we do a
1781 * retry. Because the race window is quite small.
1782 * If we seize this opportunity, it is an optimization
1783 * for increasing the success rate of dissolving page.
1789 * Move PageHWPoison flag from head page to the raw error page,
1790 * which makes any subpages rather than the error page reusable.
1792 if (PageHWPoison(head) && page != head) {
1793 SetPageHWPoison(page);
1794 ClearPageHWPoison(head);
1796 remove_hugetlb_page(h, page, false);
1797 h->max_huge_pages--;
1798 spin_unlock_irq(&hugetlb_lock);
1799 update_and_free_page(h, head);
1803 spin_unlock_irq(&hugetlb_lock);
1808 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1809 * make specified memory blocks removable from the system.
1810 * Note that this will dissolve a free gigantic hugepage completely, if any
1811 * part of it lies within the given range.
1812 * Also note that if dissolve_free_huge_page() returns with an error, all
1813 * free hugepages that were dissolved before that error are lost.
1815 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1821 if (!hugepages_supported())
1824 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1825 page = pfn_to_page(pfn);
1826 rc = dissolve_free_huge_page(page);
1835 * Allocates a fresh surplus page from the page allocator.
1837 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1838 int nid, nodemask_t *nmask)
1840 struct page *page = NULL;
1842 if (hstate_is_gigantic(h))
1845 spin_lock_irq(&hugetlb_lock);
1846 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1848 spin_unlock_irq(&hugetlb_lock);
1850 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1854 spin_lock_irq(&hugetlb_lock);
1856 * We could have raced with the pool size change.
1857 * Double check that and simply deallocate the new page
1858 * if we would end up overcommiting the surpluses. Abuse
1859 * temporary page to workaround the nasty free_huge_page
1862 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1863 SetHPageTemporary(page);
1864 spin_unlock_irq(&hugetlb_lock);
1868 h->surplus_huge_pages++;
1869 h->surplus_huge_pages_node[page_to_nid(page)]++;
1873 spin_unlock_irq(&hugetlb_lock);
1878 static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1879 int nid, nodemask_t *nmask)
1883 if (hstate_is_gigantic(h))
1886 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1891 * We do not account these pages as surplus because they are only
1892 * temporary and will be released properly on the last reference
1894 SetHPageTemporary(page);
1900 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1903 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1904 struct vm_area_struct *vma, unsigned long addr)
1907 struct mempolicy *mpol;
1908 gfp_t gfp_mask = htlb_alloc_mask(h);
1910 nodemask_t *nodemask;
1912 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1913 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1914 mpol_cond_put(mpol);
1919 /* page migration callback function */
1920 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1921 nodemask_t *nmask, gfp_t gfp_mask)
1923 spin_lock_irq(&hugetlb_lock);
1924 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1927 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1929 spin_unlock_irq(&hugetlb_lock);
1933 spin_unlock_irq(&hugetlb_lock);
1935 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1938 /* mempolicy aware migration callback */
1939 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
1940 unsigned long address)
1942 struct mempolicy *mpol;
1943 nodemask_t *nodemask;
1948 gfp_mask = htlb_alloc_mask(h);
1949 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1950 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
1951 mpol_cond_put(mpol);
1957 * Increase the hugetlb pool such that it can accommodate a reservation
1960 static int gather_surplus_pages(struct hstate *h, long delta)
1961 __must_hold(&hugetlb_lock)
1963 struct list_head surplus_list;
1964 struct page *page, *tmp;
1967 long needed, allocated;
1968 bool alloc_ok = true;
1970 lockdep_assert_held(&hugetlb_lock);
1971 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1973 h->resv_huge_pages += delta;
1978 INIT_LIST_HEAD(&surplus_list);
1982 spin_unlock_irq(&hugetlb_lock);
1983 for (i = 0; i < needed; i++) {
1984 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1985 NUMA_NO_NODE, NULL);
1990 list_add(&page->lru, &surplus_list);
1996 * After retaking hugetlb_lock, we need to recalculate 'needed'
1997 * because either resv_huge_pages or free_huge_pages may have changed.
1999 spin_lock_irq(&hugetlb_lock);
2000 needed = (h->resv_huge_pages + delta) -
2001 (h->free_huge_pages + allocated);
2006 * We were not able to allocate enough pages to
2007 * satisfy the entire reservation so we free what
2008 * we've allocated so far.
2013 * The surplus_list now contains _at_least_ the number of extra pages
2014 * needed to accommodate the reservation. Add the appropriate number
2015 * of pages to the hugetlb pool and free the extras back to the buddy
2016 * allocator. Commit the entire reservation here to prevent another
2017 * process from stealing the pages as they are added to the pool but
2018 * before they are reserved.
2020 needed += allocated;
2021 h->resv_huge_pages += delta;
2024 /* Free the needed pages to the hugetlb pool */
2025 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2031 * This page is now managed by the hugetlb allocator and has
2032 * no users -- drop the buddy allocator's reference.
2034 zeroed = put_page_testzero(page);
2035 VM_BUG_ON_PAGE(!zeroed, page);
2036 enqueue_huge_page(h, page);
2039 spin_unlock_irq(&hugetlb_lock);
2041 /* Free unnecessary surplus pages to the buddy allocator */
2042 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2044 spin_lock_irq(&hugetlb_lock);
2050 * This routine has two main purposes:
2051 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2052 * in unused_resv_pages. This corresponds to the prior adjustments made
2053 * to the associated reservation map.
2054 * 2) Free any unused surplus pages that may have been allocated to satisfy
2055 * the reservation. As many as unused_resv_pages may be freed.
2057 static void return_unused_surplus_pages(struct hstate *h,
2058 unsigned long unused_resv_pages)
2060 unsigned long nr_pages;
2062 LIST_HEAD(page_list);
2064 lockdep_assert_held(&hugetlb_lock);
2065 /* Uncommit the reservation */
2066 h->resv_huge_pages -= unused_resv_pages;
2068 /* Cannot return gigantic pages currently */
2069 if (hstate_is_gigantic(h))
2073 * Part (or even all) of the reservation could have been backed
2074 * by pre-allocated pages. Only free surplus pages.
2076 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2079 * We want to release as many surplus pages as possible, spread
2080 * evenly across all nodes with memory. Iterate across these nodes
2081 * until we can no longer free unreserved surplus pages. This occurs
2082 * when the nodes with surplus pages have no free pages.
2083 * remove_pool_huge_page() will balance the freed pages across the
2084 * on-line nodes with memory and will handle the hstate accounting.
2086 while (nr_pages--) {
2087 page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1);
2091 list_add(&page->lru, &page_list);
2095 spin_unlock_irq(&hugetlb_lock);
2096 update_and_free_pages_bulk(h, &page_list);
2097 spin_lock_irq(&hugetlb_lock);
2102 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2103 * are used by the huge page allocation routines to manage reservations.
2105 * vma_needs_reservation is called to determine if the huge page at addr
2106 * within the vma has an associated reservation. If a reservation is
2107 * needed, the value 1 is returned. The caller is then responsible for
2108 * managing the global reservation and subpool usage counts. After
2109 * the huge page has been allocated, vma_commit_reservation is called
2110 * to add the page to the reservation map. If the page allocation fails,
2111 * the reservation must be ended instead of committed. vma_end_reservation
2112 * is called in such cases.
2114 * In the normal case, vma_commit_reservation returns the same value
2115 * as the preceding vma_needs_reservation call. The only time this
2116 * is not the case is if a reserve map was changed between calls. It
2117 * is the responsibility of the caller to notice the difference and
2118 * take appropriate action.
2120 * vma_add_reservation is used in error paths where a reservation must
2121 * be restored when a newly allocated huge page must be freed. It is
2122 * to be called after calling vma_needs_reservation to determine if a
2123 * reservation exists.
2125 enum vma_resv_mode {
2131 static long __vma_reservation_common(struct hstate *h,
2132 struct vm_area_struct *vma, unsigned long addr,
2133 enum vma_resv_mode mode)
2135 struct resv_map *resv;
2138 long dummy_out_regions_needed;
2140 resv = vma_resv_map(vma);
2144 idx = vma_hugecache_offset(h, vma, addr);
2146 case VMA_NEEDS_RESV:
2147 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2148 /* We assume that vma_reservation_* routines always operate on
2149 * 1 page, and that adding to resv map a 1 page entry can only
2150 * ever require 1 region.
2152 VM_BUG_ON(dummy_out_regions_needed != 1);
2154 case VMA_COMMIT_RESV:
2155 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2156 /* region_add calls of range 1 should never fail. */
2160 region_abort(resv, idx, idx + 1, 1);
2164 if (vma->vm_flags & VM_MAYSHARE) {
2165 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2166 /* region_add calls of range 1 should never fail. */
2169 region_abort(resv, idx, idx + 1, 1);
2170 ret = region_del(resv, idx, idx + 1);
2177 if (vma->vm_flags & VM_MAYSHARE)
2180 * We know private mapping must have HPAGE_RESV_OWNER set.
2182 * In most cases, reserves always exist for private mappings.
2183 * However, a file associated with mapping could have been
2184 * hole punched or truncated after reserves were consumed.
2185 * As subsequent fault on such a range will not use reserves.
2186 * Subtle - The reserve map for private mappings has the
2187 * opposite meaning than that of shared mappings. If NO
2188 * entry is in the reserve map, it means a reservation exists.
2189 * If an entry exists in the reserve map, it means the
2190 * reservation has already been consumed. As a result, the
2191 * return value of this routine is the opposite of the
2192 * value returned from reserve map manipulation routines above.
2201 static long vma_needs_reservation(struct hstate *h,
2202 struct vm_area_struct *vma, unsigned long addr)
2204 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2207 static long vma_commit_reservation(struct hstate *h,
2208 struct vm_area_struct *vma, unsigned long addr)
2210 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2213 static void vma_end_reservation(struct hstate *h,
2214 struct vm_area_struct *vma, unsigned long addr)
2216 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2219 static long vma_add_reservation(struct hstate *h,
2220 struct vm_area_struct *vma, unsigned long addr)
2222 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2226 * This routine is called to restore a reservation on error paths. In the
2227 * specific error paths, a huge page was allocated (via alloc_huge_page)
2228 * and is about to be freed. If a reservation for the page existed,
2229 * alloc_huge_page would have consumed the reservation and set
2230 * HPageRestoreReserve in the newly allocated page. When the page is freed
2231 * via free_huge_page, the global reservation count will be incremented if
2232 * HPageRestoreReserve is set. However, free_huge_page can not adjust the
2233 * reserve map. Adjust the reserve map here to be consistent with global
2234 * reserve count adjustments to be made by free_huge_page.
2236 static void restore_reserve_on_error(struct hstate *h,
2237 struct vm_area_struct *vma, unsigned long address,
2240 if (unlikely(HPageRestoreReserve(page))) {
2241 long rc = vma_needs_reservation(h, vma, address);
2243 if (unlikely(rc < 0)) {
2245 * Rare out of memory condition in reserve map
2246 * manipulation. Clear HPageRestoreReserve so that
2247 * global reserve count will not be incremented
2248 * by free_huge_page. This will make it appear
2249 * as though the reservation for this page was
2250 * consumed. This may prevent the task from
2251 * faulting in the page at a later time. This
2252 * is better than inconsistent global huge page
2253 * accounting of reserve counts.
2255 ClearHPageRestoreReserve(page);
2257 rc = vma_add_reservation(h, vma, address);
2258 if (unlikely(rc < 0))
2260 * See above comment about rare out of
2263 ClearHPageRestoreReserve(page);
2265 vma_end_reservation(h, vma, address);
2270 * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one
2271 * @h: struct hstate old page belongs to
2272 * @old_page: Old page to dissolve
2273 * @list: List to isolate the page in case we need to
2274 * Returns 0 on success, otherwise negated error.
2276 static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
2277 struct list_head *list)
2279 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2280 int nid = page_to_nid(old_page);
2281 struct page *new_page;
2285 * Before dissolving the page, we need to allocate a new one for the
2286 * pool to remain stable. Using alloc_buddy_huge_page() allows us to
2287 * not having to deal with prep_new_huge_page() and avoids dealing of any
2288 * counters. This simplifies and let us do the whole thing under the
2291 new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
2296 spin_lock_irq(&hugetlb_lock);
2297 if (!PageHuge(old_page)) {
2299 * Freed from under us. Drop new_page too.
2302 } else if (page_count(old_page)) {
2304 * Someone has grabbed the page, try to isolate it here.
2305 * Fail with -EBUSY if not possible.
2307 spin_unlock_irq(&hugetlb_lock);
2308 if (!isolate_huge_page(old_page, list))
2310 spin_lock_irq(&hugetlb_lock);
2312 } else if (!HPageFreed(old_page)) {
2314 * Page's refcount is 0 but it has not been enqueued in the
2315 * freelist yet. Race window is small, so we can succeed here if
2318 spin_unlock_irq(&hugetlb_lock);
2323 * Ok, old_page is still a genuine free hugepage. Remove it from
2324 * the freelist and decrease the counters. These will be
2325 * incremented again when calling __prep_account_new_huge_page()
2326 * and enqueue_huge_page() for new_page. The counters will remain
2327 * stable since this happens under the lock.
2329 remove_hugetlb_page(h, old_page, false);
2332 * new_page needs to be initialized with the standard hugetlb
2333 * state. This is normally done by prep_new_huge_page() but
2334 * that takes hugetlb_lock which is already held so we need to
2335 * open code it here.
2336 * Reference count trick is needed because allocator gives us
2337 * referenced page but the pool requires pages with 0 refcount.
2339 __prep_new_huge_page(new_page);
2340 __prep_account_new_huge_page(h, nid);
2341 page_ref_dec(new_page);
2342 enqueue_huge_page(h, new_page);
2345 * Pages have been replaced, we can safely free the old one.
2347 spin_unlock_irq(&hugetlb_lock);
2348 update_and_free_page(h, old_page);
2354 spin_unlock_irq(&hugetlb_lock);
2355 __free_pages(new_page, huge_page_order(h));
2360 int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
2367 * The page might have been dissolved from under our feet, so make sure
2368 * to carefully check the state under the lock.
2369 * Return success when racing as if we dissolved the page ourselves.
2371 spin_lock_irq(&hugetlb_lock);
2372 if (PageHuge(page)) {
2373 head = compound_head(page);
2374 h = page_hstate(head);
2376 spin_unlock_irq(&hugetlb_lock);
2379 spin_unlock_irq(&hugetlb_lock);
2382 * Fence off gigantic pages as there is a cyclic dependency between
2383 * alloc_contig_range and them. Return -ENOMEM as this has the effect
2384 * of bailing out right away without further retrying.
2386 if (hstate_is_gigantic(h))
2389 if (page_count(head) && isolate_huge_page(head, list))
2391 else if (!page_count(head))
2392 ret = alloc_and_dissolve_huge_page(h, head, list);
2397 struct page *alloc_huge_page(struct vm_area_struct *vma,
2398 unsigned long addr, int avoid_reserve)
2400 struct hugepage_subpool *spool = subpool_vma(vma);
2401 struct hstate *h = hstate_vma(vma);
2403 long map_chg, map_commit;
2406 struct hugetlb_cgroup *h_cg;
2407 bool deferred_reserve;
2409 idx = hstate_index(h);
2411 * Examine the region/reserve map to determine if the process
2412 * has a reservation for the page to be allocated. A return
2413 * code of zero indicates a reservation exists (no change).
2415 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2417 return ERR_PTR(-ENOMEM);
2420 * Processes that did not create the mapping will have no
2421 * reserves as indicated by the region/reserve map. Check
2422 * that the allocation will not exceed the subpool limit.
2423 * Allocations for MAP_NORESERVE mappings also need to be
2424 * checked against any subpool limit.
2426 if (map_chg || avoid_reserve) {
2427 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2429 vma_end_reservation(h, vma, addr);
2430 return ERR_PTR(-ENOSPC);
2434 * Even though there was no reservation in the region/reserve
2435 * map, there could be reservations associated with the
2436 * subpool that can be used. This would be indicated if the
2437 * return value of hugepage_subpool_get_pages() is zero.
2438 * However, if avoid_reserve is specified we still avoid even
2439 * the subpool reservations.
2445 /* If this allocation is not consuming a reservation, charge it now.
2447 deferred_reserve = map_chg || avoid_reserve;
2448 if (deferred_reserve) {
2449 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2450 idx, pages_per_huge_page(h), &h_cg);
2452 goto out_subpool_put;
2455 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2457 goto out_uncharge_cgroup_reservation;
2459 spin_lock_irq(&hugetlb_lock);
2461 * glb_chg is passed to indicate whether or not a page must be taken
2462 * from the global free pool (global change). gbl_chg == 0 indicates
2463 * a reservation exists for the allocation.
2465 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2467 spin_unlock_irq(&hugetlb_lock);
2468 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2470 goto out_uncharge_cgroup;
2471 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2472 SetHPageRestoreReserve(page);
2473 h->resv_huge_pages--;
2475 spin_lock_irq(&hugetlb_lock);
2476 list_add(&page->lru, &h->hugepage_activelist);
2479 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2480 /* If allocation is not consuming a reservation, also store the
2481 * hugetlb_cgroup pointer on the page.
2483 if (deferred_reserve) {
2484 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2488 spin_unlock_irq(&hugetlb_lock);
2490 hugetlb_set_page_subpool(page, spool);
2492 map_commit = vma_commit_reservation(h, vma, addr);
2493 if (unlikely(map_chg > map_commit)) {
2495 * The page was added to the reservation map between
2496 * vma_needs_reservation and vma_commit_reservation.
2497 * This indicates a race with hugetlb_reserve_pages.
2498 * Adjust for the subpool count incremented above AND
2499 * in hugetlb_reserve_pages for the same page. Also,
2500 * the reservation count added in hugetlb_reserve_pages
2501 * no longer applies.
2505 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2506 hugetlb_acct_memory(h, -rsv_adjust);
2507 if (deferred_reserve)
2508 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2509 pages_per_huge_page(h), page);
2513 out_uncharge_cgroup:
2514 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2515 out_uncharge_cgroup_reservation:
2516 if (deferred_reserve)
2517 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2520 if (map_chg || avoid_reserve)
2521 hugepage_subpool_put_pages(spool, 1);
2522 vma_end_reservation(h, vma, addr);
2523 return ERR_PTR(-ENOSPC);
2526 int alloc_bootmem_huge_page(struct hstate *h)
2527 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2528 int __alloc_bootmem_huge_page(struct hstate *h)
2530 struct huge_bootmem_page *m;
2533 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2536 addr = memblock_alloc_try_nid_raw(
2537 huge_page_size(h), huge_page_size(h),
2538 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2541 * Use the beginning of the huge page to store the
2542 * huge_bootmem_page struct (until gather_bootmem
2543 * puts them into the mem_map).
2552 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2553 /* Put them into a private list first because mem_map is not up yet */
2554 INIT_LIST_HEAD(&m->list);
2555 list_add(&m->list, &huge_boot_pages);
2560 static void __init prep_compound_huge_page(struct page *page,
2563 if (unlikely(order > (MAX_ORDER - 1)))
2564 prep_compound_gigantic_page(page, order);
2566 prep_compound_page(page, order);
2569 /* Put bootmem huge pages into the standard lists after mem_map is up */
2570 static void __init gather_bootmem_prealloc(void)
2572 struct huge_bootmem_page *m;
2574 list_for_each_entry(m, &huge_boot_pages, list) {
2575 struct page *page = virt_to_page(m);
2576 struct hstate *h = m->hstate;
2578 WARN_ON(page_count(page) != 1);
2579 prep_compound_huge_page(page, huge_page_order(h));
2580 WARN_ON(PageReserved(page));
2581 prep_new_huge_page(h, page, page_to_nid(page));
2582 put_page(page); /* free it into the hugepage allocator */
2585 * If we had gigantic hugepages allocated at boot time, we need
2586 * to restore the 'stolen' pages to totalram_pages in order to
2587 * fix confusing memory reports from free(1) and another
2588 * side-effects, like CommitLimit going negative.
2590 if (hstate_is_gigantic(h))
2591 adjust_managed_page_count(page, pages_per_huge_page(h));
2596 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2599 nodemask_t *node_alloc_noretry;
2601 if (!hstate_is_gigantic(h)) {
2603 * Bit mask controlling how hard we retry per-node allocations.
2604 * Ignore errors as lower level routines can deal with
2605 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2606 * time, we are likely in bigger trouble.
2608 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2611 /* allocations done at boot time */
2612 node_alloc_noretry = NULL;
2615 /* bit mask controlling how hard we retry per-node allocations */
2616 if (node_alloc_noretry)
2617 nodes_clear(*node_alloc_noretry);
2619 for (i = 0; i < h->max_huge_pages; ++i) {
2620 if (hstate_is_gigantic(h)) {
2621 if (hugetlb_cma_size) {
2622 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2625 if (!alloc_bootmem_huge_page(h))
2627 } else if (!alloc_pool_huge_page(h,
2628 &node_states[N_MEMORY],
2629 node_alloc_noretry))
2633 if (i < h->max_huge_pages) {
2636 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2637 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2638 h->max_huge_pages, buf, i);
2639 h->max_huge_pages = i;
2642 kfree(node_alloc_noretry);
2645 static void __init hugetlb_init_hstates(void)
2649 for_each_hstate(h) {
2650 if (minimum_order > huge_page_order(h))
2651 minimum_order = huge_page_order(h);
2653 /* oversize hugepages were init'ed in early boot */
2654 if (!hstate_is_gigantic(h))
2655 hugetlb_hstate_alloc_pages(h);
2657 VM_BUG_ON(minimum_order == UINT_MAX);
2660 static void __init report_hugepages(void)
2664 for_each_hstate(h) {
2667 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2668 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2669 buf, h->free_huge_pages);
2673 #ifdef CONFIG_HIGHMEM
2674 static void try_to_free_low(struct hstate *h, unsigned long count,
2675 nodemask_t *nodes_allowed)
2678 LIST_HEAD(page_list);
2680 lockdep_assert_held(&hugetlb_lock);
2681 if (hstate_is_gigantic(h))
2685 * Collect pages to be freed on a list, and free after dropping lock
2687 for_each_node_mask(i, *nodes_allowed) {
2688 struct page *page, *next;
2689 struct list_head *freel = &h->hugepage_freelists[i];
2690 list_for_each_entry_safe(page, next, freel, lru) {
2691 if (count >= h->nr_huge_pages)
2693 if (PageHighMem(page))
2695 remove_hugetlb_page(h, page, false);
2696 list_add(&page->lru, &page_list);
2701 spin_unlock_irq(&hugetlb_lock);
2702 update_and_free_pages_bulk(h, &page_list);
2703 spin_lock_irq(&hugetlb_lock);
2706 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2707 nodemask_t *nodes_allowed)
2713 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2714 * balanced by operating on them in a round-robin fashion.
2715 * Returns 1 if an adjustment was made.
2717 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2722 lockdep_assert_held(&hugetlb_lock);
2723 VM_BUG_ON(delta != -1 && delta != 1);
2726 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2727 if (h->surplus_huge_pages_node[node])
2731 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2732 if (h->surplus_huge_pages_node[node] <
2733 h->nr_huge_pages_node[node])
2740 h->surplus_huge_pages += delta;
2741 h->surplus_huge_pages_node[node] += delta;
2745 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2746 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2747 nodemask_t *nodes_allowed)
2749 unsigned long min_count, ret;
2751 LIST_HEAD(page_list);
2752 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2755 * Bit mask controlling how hard we retry per-node allocations.
2756 * If we can not allocate the bit mask, do not attempt to allocate
2757 * the requested huge pages.
2759 if (node_alloc_noretry)
2760 nodes_clear(*node_alloc_noretry);
2765 * resize_lock mutex prevents concurrent adjustments to number of
2766 * pages in hstate via the proc/sysfs interfaces.
2768 mutex_lock(&h->resize_lock);
2769 spin_lock_irq(&hugetlb_lock);
2772 * Check for a node specific request.
2773 * Changing node specific huge page count may require a corresponding
2774 * change to the global count. In any case, the passed node mask
2775 * (nodes_allowed) will restrict alloc/free to the specified node.
2777 if (nid != NUMA_NO_NODE) {
2778 unsigned long old_count = count;
2780 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2782 * User may have specified a large count value which caused the
2783 * above calculation to overflow. In this case, they wanted
2784 * to allocate as many huge pages as possible. Set count to
2785 * largest possible value to align with their intention.
2787 if (count < old_count)
2792 * Gigantic pages runtime allocation depend on the capability for large
2793 * page range allocation.
2794 * If the system does not provide this feature, return an error when
2795 * the user tries to allocate gigantic pages but let the user free the
2796 * boottime allocated gigantic pages.
2798 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2799 if (count > persistent_huge_pages(h)) {
2800 spin_unlock_irq(&hugetlb_lock);
2801 mutex_unlock(&h->resize_lock);
2802 NODEMASK_FREE(node_alloc_noretry);
2805 /* Fall through to decrease pool */
2809 * Increase the pool size
2810 * First take pages out of surplus state. Then make up the
2811 * remaining difference by allocating fresh huge pages.
2813 * We might race with alloc_surplus_huge_page() here and be unable
2814 * to convert a surplus huge page to a normal huge page. That is
2815 * not critical, though, it just means the overall size of the
2816 * pool might be one hugepage larger than it needs to be, but
2817 * within all the constraints specified by the sysctls.
2819 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2820 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2824 while (count > persistent_huge_pages(h)) {
2826 * If this allocation races such that we no longer need the
2827 * page, free_huge_page will handle it by freeing the page
2828 * and reducing the surplus.
2830 spin_unlock_irq(&hugetlb_lock);
2832 /* yield cpu to avoid soft lockup */
2835 ret = alloc_pool_huge_page(h, nodes_allowed,
2836 node_alloc_noretry);
2837 spin_lock_irq(&hugetlb_lock);
2841 /* Bail for signals. Probably ctrl-c from user */
2842 if (signal_pending(current))
2847 * Decrease the pool size
2848 * First return free pages to the buddy allocator (being careful
2849 * to keep enough around to satisfy reservations). Then place
2850 * pages into surplus state as needed so the pool will shrink
2851 * to the desired size as pages become free.
2853 * By placing pages into the surplus state independent of the
2854 * overcommit value, we are allowing the surplus pool size to
2855 * exceed overcommit. There are few sane options here. Since
2856 * alloc_surplus_huge_page() is checking the global counter,
2857 * though, we'll note that we're not allowed to exceed surplus
2858 * and won't grow the pool anywhere else. Not until one of the
2859 * sysctls are changed, or the surplus pages go out of use.
2861 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2862 min_count = max(count, min_count);
2863 try_to_free_low(h, min_count, nodes_allowed);
2866 * Collect pages to be removed on list without dropping lock
2868 while (min_count < persistent_huge_pages(h)) {
2869 page = remove_pool_huge_page(h, nodes_allowed, 0);
2873 list_add(&page->lru, &page_list);
2875 /* free the pages after dropping lock */
2876 spin_unlock_irq(&hugetlb_lock);
2877 update_and_free_pages_bulk(h, &page_list);
2878 spin_lock_irq(&hugetlb_lock);
2880 while (count < persistent_huge_pages(h)) {
2881 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2885 h->max_huge_pages = persistent_huge_pages(h);
2886 spin_unlock_irq(&hugetlb_lock);
2887 mutex_unlock(&h->resize_lock);
2889 NODEMASK_FREE(node_alloc_noretry);
2894 #define HSTATE_ATTR_RO(_name) \
2895 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2897 #define HSTATE_ATTR(_name) \
2898 static struct kobj_attribute _name##_attr = \
2899 __ATTR(_name, 0644, _name##_show, _name##_store)
2901 static struct kobject *hugepages_kobj;
2902 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2904 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2906 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2910 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2911 if (hstate_kobjs[i] == kobj) {
2913 *nidp = NUMA_NO_NODE;
2917 return kobj_to_node_hstate(kobj, nidp);
2920 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2921 struct kobj_attribute *attr, char *buf)
2924 unsigned long nr_huge_pages;
2927 h = kobj_to_hstate(kobj, &nid);
2928 if (nid == NUMA_NO_NODE)
2929 nr_huge_pages = h->nr_huge_pages;
2931 nr_huge_pages = h->nr_huge_pages_node[nid];
2933 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
2936 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2937 struct hstate *h, int nid,
2938 unsigned long count, size_t len)
2941 nodemask_t nodes_allowed, *n_mask;
2943 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2946 if (nid == NUMA_NO_NODE) {
2948 * global hstate attribute
2950 if (!(obey_mempolicy &&
2951 init_nodemask_of_mempolicy(&nodes_allowed)))
2952 n_mask = &node_states[N_MEMORY];
2954 n_mask = &nodes_allowed;
2957 * Node specific request. count adjustment happens in
2958 * set_max_huge_pages() after acquiring hugetlb_lock.
2960 init_nodemask_of_node(&nodes_allowed, nid);
2961 n_mask = &nodes_allowed;
2964 err = set_max_huge_pages(h, count, nid, n_mask);
2966 return err ? err : len;
2969 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2970 struct kobject *kobj, const char *buf,
2974 unsigned long count;
2978 err = kstrtoul(buf, 10, &count);
2982 h = kobj_to_hstate(kobj, &nid);
2983 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2986 static ssize_t nr_hugepages_show(struct kobject *kobj,
2987 struct kobj_attribute *attr, char *buf)
2989 return nr_hugepages_show_common(kobj, attr, buf);
2992 static ssize_t nr_hugepages_store(struct kobject *kobj,
2993 struct kobj_attribute *attr, const char *buf, size_t len)
2995 return nr_hugepages_store_common(false, kobj, buf, len);
2997 HSTATE_ATTR(nr_hugepages);
3002 * hstate attribute for optionally mempolicy-based constraint on persistent
3003 * huge page alloc/free.
3005 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
3006 struct kobj_attribute *attr,
3009 return nr_hugepages_show_common(kobj, attr, buf);
3012 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
3013 struct kobj_attribute *attr, const char *buf, size_t len)
3015 return nr_hugepages_store_common(true, kobj, buf, len);
3017 HSTATE_ATTR(nr_hugepages_mempolicy);
3021 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
3022 struct kobj_attribute *attr, char *buf)
3024 struct hstate *h = kobj_to_hstate(kobj, NULL);
3025 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
3028 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
3029 struct kobj_attribute *attr, const char *buf, size_t count)
3032 unsigned long input;
3033 struct hstate *h = kobj_to_hstate(kobj, NULL);
3035 if (hstate_is_gigantic(h))
3038 err = kstrtoul(buf, 10, &input);
3042 spin_lock_irq(&hugetlb_lock);
3043 h->nr_overcommit_huge_pages = input;
3044 spin_unlock_irq(&hugetlb_lock);
3048 HSTATE_ATTR(nr_overcommit_hugepages);
3050 static ssize_t free_hugepages_show(struct kobject *kobj,
3051 struct kobj_attribute *attr, char *buf)
3054 unsigned long free_huge_pages;
3057 h = kobj_to_hstate(kobj, &nid);
3058 if (nid == NUMA_NO_NODE)
3059 free_huge_pages = h->free_huge_pages;
3061 free_huge_pages = h->free_huge_pages_node[nid];
3063 return sysfs_emit(buf, "%lu\n", free_huge_pages);
3065 HSTATE_ATTR_RO(free_hugepages);
3067 static ssize_t resv_hugepages_show(struct kobject *kobj,
3068 struct kobj_attribute *attr, char *buf)
3070 struct hstate *h = kobj_to_hstate(kobj, NULL);
3071 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
3073 HSTATE_ATTR_RO(resv_hugepages);
3075 static ssize_t surplus_hugepages_show(struct kobject *kobj,
3076 struct kobj_attribute *attr, char *buf)
3079 unsigned long surplus_huge_pages;
3082 h = kobj_to_hstate(kobj, &nid);
3083 if (nid == NUMA_NO_NODE)
3084 surplus_huge_pages = h->surplus_huge_pages;
3086 surplus_huge_pages = h->surplus_huge_pages_node[nid];
3088 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
3090 HSTATE_ATTR_RO(surplus_hugepages);
3092 static struct attribute *hstate_attrs[] = {
3093 &nr_hugepages_attr.attr,
3094 &nr_overcommit_hugepages_attr.attr,
3095 &free_hugepages_attr.attr,
3096 &resv_hugepages_attr.attr,
3097 &surplus_hugepages_attr.attr,
3099 &nr_hugepages_mempolicy_attr.attr,
3104 static const struct attribute_group hstate_attr_group = {
3105 .attrs = hstate_attrs,
3108 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
3109 struct kobject **hstate_kobjs,
3110 const struct attribute_group *hstate_attr_group)
3113 int hi = hstate_index(h);
3115 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3116 if (!hstate_kobjs[hi])
3119 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3121 kobject_put(hstate_kobjs[hi]);
3122 hstate_kobjs[hi] = NULL;
3128 static void __init hugetlb_sysfs_init(void)
3133 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3134 if (!hugepages_kobj)
3137 for_each_hstate(h) {
3138 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3139 hstate_kobjs, &hstate_attr_group);
3141 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3148 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3149 * with node devices in node_devices[] using a parallel array. The array
3150 * index of a node device or _hstate == node id.
3151 * This is here to avoid any static dependency of the node device driver, in
3152 * the base kernel, on the hugetlb module.
3154 struct node_hstate {
3155 struct kobject *hugepages_kobj;
3156 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3158 static struct node_hstate node_hstates[MAX_NUMNODES];
3161 * A subset of global hstate attributes for node devices
3163 static struct attribute *per_node_hstate_attrs[] = {
3164 &nr_hugepages_attr.attr,
3165 &free_hugepages_attr.attr,
3166 &surplus_hugepages_attr.attr,
3170 static const struct attribute_group per_node_hstate_attr_group = {
3171 .attrs = per_node_hstate_attrs,
3175 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3176 * Returns node id via non-NULL nidp.
3178 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3182 for (nid = 0; nid < nr_node_ids; nid++) {
3183 struct node_hstate *nhs = &node_hstates[nid];
3185 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3186 if (nhs->hstate_kobjs[i] == kobj) {
3198 * Unregister hstate attributes from a single node device.
3199 * No-op if no hstate attributes attached.
3201 static void hugetlb_unregister_node(struct node *node)
3204 struct node_hstate *nhs = &node_hstates[node->dev.id];
3206 if (!nhs->hugepages_kobj)
3207 return; /* no hstate attributes */
3209 for_each_hstate(h) {
3210 int idx = hstate_index(h);
3211 if (nhs->hstate_kobjs[idx]) {
3212 kobject_put(nhs->hstate_kobjs[idx]);
3213 nhs->hstate_kobjs[idx] = NULL;
3217 kobject_put(nhs->hugepages_kobj);
3218 nhs->hugepages_kobj = NULL;
3223 * Register hstate attributes for a single node device.
3224 * No-op if attributes already registered.
3226 static void hugetlb_register_node(struct node *node)
3229 struct node_hstate *nhs = &node_hstates[node->dev.id];
3232 if (nhs->hugepages_kobj)
3233 return; /* already allocated */
3235 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3237 if (!nhs->hugepages_kobj)
3240 for_each_hstate(h) {
3241 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3243 &per_node_hstate_attr_group);
3245 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3246 h->name, node->dev.id);
3247 hugetlb_unregister_node(node);
3254 * hugetlb init time: register hstate attributes for all registered node
3255 * devices of nodes that have memory. All on-line nodes should have
3256 * registered their associated device by this time.
3258 static void __init hugetlb_register_all_nodes(void)
3262 for_each_node_state(nid, N_MEMORY) {
3263 struct node *node = node_devices[nid];
3264 if (node->dev.id == nid)
3265 hugetlb_register_node(node);
3269 * Let the node device driver know we're here so it can
3270 * [un]register hstate attributes on node hotplug.
3272 register_hugetlbfs_with_node(hugetlb_register_node,
3273 hugetlb_unregister_node);
3275 #else /* !CONFIG_NUMA */
3277 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3285 static void hugetlb_register_all_nodes(void) { }
3289 static int __init hugetlb_init(void)
3293 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3296 if (!hugepages_supported()) {
3297 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3298 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3303 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3304 * architectures depend on setup being done here.
3306 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3307 if (!parsed_default_hugepagesz) {
3309 * If we did not parse a default huge page size, set
3310 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3311 * number of huge pages for this default size was implicitly
3312 * specified, set that here as well.
3313 * Note that the implicit setting will overwrite an explicit
3314 * setting. A warning will be printed in this case.
3316 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3317 if (default_hstate_max_huge_pages) {
3318 if (default_hstate.max_huge_pages) {
3321 string_get_size(huge_page_size(&default_hstate),
3322 1, STRING_UNITS_2, buf, 32);
3323 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3324 default_hstate.max_huge_pages, buf);
3325 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3326 default_hstate_max_huge_pages);
3328 default_hstate.max_huge_pages =
3329 default_hstate_max_huge_pages;
3333 hugetlb_cma_check();
3334 hugetlb_init_hstates();
3335 gather_bootmem_prealloc();
3338 hugetlb_sysfs_init();
3339 hugetlb_register_all_nodes();
3340 hugetlb_cgroup_file_init();
3343 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3345 num_fault_mutexes = 1;
3347 hugetlb_fault_mutex_table =
3348 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3350 BUG_ON(!hugetlb_fault_mutex_table);
3352 for (i = 0; i < num_fault_mutexes; i++)
3353 mutex_init(&hugetlb_fault_mutex_table[i]);
3356 subsys_initcall(hugetlb_init);
3358 /* Overwritten by architectures with more huge page sizes */
3359 bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3361 return size == HPAGE_SIZE;
3364 void __init hugetlb_add_hstate(unsigned int order)
3369 if (size_to_hstate(PAGE_SIZE << order)) {
3372 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3374 h = &hstates[hugetlb_max_hstate++];
3375 mutex_init(&h->resize_lock);
3377 h->mask = ~(huge_page_size(h) - 1);
3378 for (i = 0; i < MAX_NUMNODES; ++i)
3379 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3380 INIT_LIST_HEAD(&h->hugepage_activelist);
3381 h->next_nid_to_alloc = first_memory_node;
3382 h->next_nid_to_free = first_memory_node;
3383 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3384 huge_page_size(h)/1024);
3390 * hugepages command line processing
3391 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3392 * specification. If not, ignore the hugepages value. hugepages can also
3393 * be the first huge page command line option in which case it implicitly
3394 * specifies the number of huge pages for the default size.
3396 static int __init hugepages_setup(char *s)
3399 static unsigned long *last_mhp;
3401 if (!parsed_valid_hugepagesz) {
3402 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3403 parsed_valid_hugepagesz = true;
3408 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3409 * yet, so this hugepages= parameter goes to the "default hstate".
3410 * Otherwise, it goes with the previously parsed hugepagesz or
3411 * default_hugepagesz.
3413 else if (!hugetlb_max_hstate)
3414 mhp = &default_hstate_max_huge_pages;
3416 mhp = &parsed_hstate->max_huge_pages;
3418 if (mhp == last_mhp) {
3419 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3423 if (sscanf(s, "%lu", mhp) <= 0)
3427 * Global state is always initialized later in hugetlb_init.
3428 * But we need to allocate gigantic hstates here early to still
3429 * use the bootmem allocator.
3431 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
3432 hugetlb_hstate_alloc_pages(parsed_hstate);
3438 __setup("hugepages=", hugepages_setup);
3441 * hugepagesz command line processing
3442 * A specific huge page size can only be specified once with hugepagesz.
3443 * hugepagesz is followed by hugepages on the command line. The global
3444 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3445 * hugepagesz argument was valid.
3447 static int __init hugepagesz_setup(char *s)
3452 parsed_valid_hugepagesz = false;
3453 size = (unsigned long)memparse(s, NULL);
3455 if (!arch_hugetlb_valid_size(size)) {
3456 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3460 h = size_to_hstate(size);
3463 * hstate for this size already exists. This is normally
3464 * an error, but is allowed if the existing hstate is the
3465 * default hstate. More specifically, it is only allowed if
3466 * the number of huge pages for the default hstate was not
3467 * previously specified.
3469 if (!parsed_default_hugepagesz || h != &default_hstate ||
3470 default_hstate.max_huge_pages) {
3471 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3476 * No need to call hugetlb_add_hstate() as hstate already
3477 * exists. But, do set parsed_hstate so that a following
3478 * hugepages= parameter will be applied to this hstate.
3481 parsed_valid_hugepagesz = true;
3485 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3486 parsed_valid_hugepagesz = true;
3489 __setup("hugepagesz=", hugepagesz_setup);
3492 * default_hugepagesz command line input
3493 * Only one instance of default_hugepagesz allowed on command line.
3495 static int __init default_hugepagesz_setup(char *s)
3499 parsed_valid_hugepagesz = false;
3500 if (parsed_default_hugepagesz) {
3501 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3505 size = (unsigned long)memparse(s, NULL);
3507 if (!arch_hugetlb_valid_size(size)) {
3508 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3512 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3513 parsed_valid_hugepagesz = true;
3514 parsed_default_hugepagesz = true;
3515 default_hstate_idx = hstate_index(size_to_hstate(size));
3518 * The number of default huge pages (for this size) could have been
3519 * specified as the first hugetlb parameter: hugepages=X. If so,
3520 * then default_hstate_max_huge_pages is set. If the default huge
3521 * page size is gigantic (>= MAX_ORDER), then the pages must be
3522 * allocated here from bootmem allocator.
3524 if (default_hstate_max_huge_pages) {
3525 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3526 if (hstate_is_gigantic(&default_hstate))
3527 hugetlb_hstate_alloc_pages(&default_hstate);
3528 default_hstate_max_huge_pages = 0;
3533 __setup("default_hugepagesz=", default_hugepagesz_setup);
3535 static unsigned int allowed_mems_nr(struct hstate *h)
3538 unsigned int nr = 0;
3539 nodemask_t *mpol_allowed;
3540 unsigned int *array = h->free_huge_pages_node;
3541 gfp_t gfp_mask = htlb_alloc_mask(h);
3543 mpol_allowed = policy_nodemask_current(gfp_mask);
3545 for_each_node_mask(node, cpuset_current_mems_allowed) {
3546 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3553 #ifdef CONFIG_SYSCTL
3554 static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3555 void *buffer, size_t *length,
3556 loff_t *ppos, unsigned long *out)
3558 struct ctl_table dup_table;
3561 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3562 * can duplicate the @table and alter the duplicate of it.
3565 dup_table.data = out;
3567 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3570 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3571 struct ctl_table *table, int write,
3572 void *buffer, size_t *length, loff_t *ppos)
3574 struct hstate *h = &default_hstate;
3575 unsigned long tmp = h->max_huge_pages;
3578 if (!hugepages_supported())
3581 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3587 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3588 NUMA_NO_NODE, tmp, *length);
3593 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3594 void *buffer, size_t *length, loff_t *ppos)
3597 return hugetlb_sysctl_handler_common(false, table, write,
3598 buffer, length, ppos);
3602 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3603 void *buffer, size_t *length, loff_t *ppos)
3605 return hugetlb_sysctl_handler_common(true, table, write,
3606 buffer, length, ppos);
3608 #endif /* CONFIG_NUMA */
3610 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3611 void *buffer, size_t *length, loff_t *ppos)
3613 struct hstate *h = &default_hstate;
3617 if (!hugepages_supported())
3620 tmp = h->nr_overcommit_huge_pages;
3622 if (write && hstate_is_gigantic(h))
3625 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3631 spin_lock_irq(&hugetlb_lock);
3632 h->nr_overcommit_huge_pages = tmp;
3633 spin_unlock_irq(&hugetlb_lock);
3639 #endif /* CONFIG_SYSCTL */
3641 void hugetlb_report_meminfo(struct seq_file *m)
3644 unsigned long total = 0;
3646 if (!hugepages_supported())
3649 for_each_hstate(h) {
3650 unsigned long count = h->nr_huge_pages;
3652 total += huge_page_size(h) * count;
3654 if (h == &default_hstate)
3656 "HugePages_Total: %5lu\n"
3657 "HugePages_Free: %5lu\n"
3658 "HugePages_Rsvd: %5lu\n"
3659 "HugePages_Surp: %5lu\n"
3660 "Hugepagesize: %8lu kB\n",
3664 h->surplus_huge_pages,
3665 huge_page_size(h) / SZ_1K);
3668 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3671 int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3673 struct hstate *h = &default_hstate;
3675 if (!hugepages_supported())
3678 return sysfs_emit_at(buf, len,
3679 "Node %d HugePages_Total: %5u\n"
3680 "Node %d HugePages_Free: %5u\n"
3681 "Node %d HugePages_Surp: %5u\n",
3682 nid, h->nr_huge_pages_node[nid],
3683 nid, h->free_huge_pages_node[nid],
3684 nid, h->surplus_huge_pages_node[nid]);
3687 void hugetlb_show_meminfo(void)
3692 if (!hugepages_supported())
3695 for_each_node_state(nid, N_MEMORY)
3697 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3699 h->nr_huge_pages_node[nid],
3700 h->free_huge_pages_node[nid],
3701 h->surplus_huge_pages_node[nid],
3702 huge_page_size(h) / SZ_1K);
3705 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3707 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3708 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3711 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3712 unsigned long hugetlb_total_pages(void)
3715 unsigned long nr_total_pages = 0;
3718 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3719 return nr_total_pages;
3722 static int hugetlb_acct_memory(struct hstate *h, long delta)
3729 spin_lock_irq(&hugetlb_lock);
3731 * When cpuset is configured, it breaks the strict hugetlb page
3732 * reservation as the accounting is done on a global variable. Such
3733 * reservation is completely rubbish in the presence of cpuset because
3734 * the reservation is not checked against page availability for the
3735 * current cpuset. Application can still potentially OOM'ed by kernel
3736 * with lack of free htlb page in cpuset that the task is in.
3737 * Attempt to enforce strict accounting with cpuset is almost
3738 * impossible (or too ugly) because cpuset is too fluid that
3739 * task or memory node can be dynamically moved between cpusets.
3741 * The change of semantics for shared hugetlb mapping with cpuset is
3742 * undesirable. However, in order to preserve some of the semantics,
3743 * we fall back to check against current free page availability as
3744 * a best attempt and hopefully to minimize the impact of changing
3745 * semantics that cpuset has.
3747 * Apart from cpuset, we also have memory policy mechanism that
3748 * also determines from which node the kernel will allocate memory
3749 * in a NUMA system. So similar to cpuset, we also should consider
3750 * the memory policy of the current task. Similar to the description
3754 if (gather_surplus_pages(h, delta) < 0)
3757 if (delta > allowed_mems_nr(h)) {
3758 return_unused_surplus_pages(h, delta);
3765 return_unused_surplus_pages(h, (unsigned long) -delta);
3768 spin_unlock_irq(&hugetlb_lock);
3772 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3774 struct resv_map *resv = vma_resv_map(vma);
3777 * This new VMA should share its siblings reservation map if present.
3778 * The VMA will only ever have a valid reservation map pointer where
3779 * it is being copied for another still existing VMA. As that VMA
3780 * has a reference to the reservation map it cannot disappear until
3781 * after this open call completes. It is therefore safe to take a
3782 * new reference here without additional locking.
3784 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3785 kref_get(&resv->refs);
3788 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3790 struct hstate *h = hstate_vma(vma);
3791 struct resv_map *resv = vma_resv_map(vma);
3792 struct hugepage_subpool *spool = subpool_vma(vma);
3793 unsigned long reserve, start, end;
3796 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3799 start = vma_hugecache_offset(h, vma, vma->vm_start);
3800 end = vma_hugecache_offset(h, vma, vma->vm_end);
3802 reserve = (end - start) - region_count(resv, start, end);
3803 hugetlb_cgroup_uncharge_counter(resv, start, end);
3806 * Decrement reserve counts. The global reserve count may be
3807 * adjusted if the subpool has a minimum size.
3809 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3810 hugetlb_acct_memory(h, -gbl_reserve);
3813 kref_put(&resv->refs, resv_map_release);
3816 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3818 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3823 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3825 return huge_page_size(hstate_vma(vma));
3829 * We cannot handle pagefaults against hugetlb pages at all. They cause
3830 * handle_mm_fault() to try to instantiate regular-sized pages in the
3831 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3834 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3841 * When a new function is introduced to vm_operations_struct and added
3842 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3843 * This is because under System V memory model, mappings created via
3844 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3845 * their original vm_ops are overwritten with shm_vm_ops.
3847 const struct vm_operations_struct hugetlb_vm_ops = {
3848 .fault = hugetlb_vm_op_fault,
3849 .open = hugetlb_vm_op_open,
3850 .close = hugetlb_vm_op_close,
3851 .may_split = hugetlb_vm_op_split,
3852 .pagesize = hugetlb_vm_op_pagesize,
3855 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3861 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3862 vma->vm_page_prot)));
3864 entry = huge_pte_wrprotect(mk_huge_pte(page,
3865 vma->vm_page_prot));
3867 entry = pte_mkyoung(entry);
3868 entry = pte_mkhuge(entry);
3869 entry = arch_make_huge_pte(entry, vma, page, writable);
3874 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3875 unsigned long address, pte_t *ptep)
3879 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3880 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3881 update_mmu_cache(vma, address, ptep);
3884 bool is_hugetlb_entry_migration(pte_t pte)
3888 if (huge_pte_none(pte) || pte_present(pte))
3890 swp = pte_to_swp_entry(pte);
3891 if (is_migration_entry(swp))
3897 static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3901 if (huge_pte_none(pte) || pte_present(pte))
3903 swp = pte_to_swp_entry(pte);
3904 if (is_hwpoison_entry(swp))
3911 hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
3912 struct page *new_page)
3914 __SetPageUptodate(new_page);
3915 set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1));
3916 hugepage_add_new_anon_rmap(new_page, vma, addr);
3917 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
3918 ClearHPageRestoreReserve(new_page);
3919 SetHPageMigratable(new_page);
3922 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3923 struct vm_area_struct *vma)
3925 pte_t *src_pte, *dst_pte, entry, dst_entry;
3926 struct page *ptepage;
3928 bool cow = is_cow_mapping(vma->vm_flags);
3929 struct hstate *h = hstate_vma(vma);
3930 unsigned long sz = huge_page_size(h);
3931 unsigned long npages = pages_per_huge_page(h);
3932 struct address_space *mapping = vma->vm_file->f_mapping;
3933 struct mmu_notifier_range range;
3937 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3940 mmu_notifier_invalidate_range_start(&range);
3943 * For shared mappings i_mmap_rwsem must be held to call
3944 * huge_pte_alloc, otherwise the returned ptep could go
3945 * away if part of a shared pmd and another thread calls
3948 i_mmap_lock_read(mapping);
3951 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3952 spinlock_t *src_ptl, *dst_ptl;
3953 src_pte = huge_pte_offset(src, addr, sz);
3956 dst_pte = huge_pte_alloc(dst, vma, addr, sz);
3963 * If the pagetables are shared don't copy or take references.
3964 * dst_pte == src_pte is the common case of src/dest sharing.
3966 * However, src could have 'unshared' and dst shares with
3967 * another vma. If dst_pte !none, this implies sharing.
3968 * Check here before taking page table lock, and once again
3969 * after taking the lock below.
3971 dst_entry = huge_ptep_get(dst_pte);
3972 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3975 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3976 src_ptl = huge_pte_lockptr(h, src, src_pte);
3977 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3978 entry = huge_ptep_get(src_pte);
3979 dst_entry = huge_ptep_get(dst_pte);
3981 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3983 * Skip if src entry none. Also, skip in the
3984 * unlikely case dst entry !none as this implies
3985 * sharing with another vma.
3988 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3989 is_hugetlb_entry_hwpoisoned(entry))) {
3990 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3992 if (is_write_migration_entry(swp_entry) && cow) {
3994 * COW mappings require pages in both
3995 * parent and child to be set to read.
3997 make_migration_entry_read(&swp_entry);
3998 entry = swp_entry_to_pte(swp_entry);
3999 set_huge_swap_pte_at(src, addr, src_pte,
4002 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
4004 entry = huge_ptep_get(src_pte);
4005 ptepage = pte_page(entry);
4009 * This is a rare case where we see pinned hugetlb
4010 * pages while they're prone to COW. We need to do the
4011 * COW earlier during fork.
4013 * When pre-allocating the page or copying data, we
4014 * need to be without the pgtable locks since we could
4015 * sleep during the process.
4017 if (unlikely(page_needs_cow_for_dma(vma, ptepage))) {
4018 pte_t src_pte_old = entry;
4021 spin_unlock(src_ptl);
4022 spin_unlock(dst_ptl);
4023 /* Do not use reserve as it's private owned */
4024 new = alloc_huge_page(vma, addr, 1);
4030 copy_user_huge_page(new, ptepage, addr, vma,
4034 /* Install the new huge page if src pte stable */
4035 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4036 src_ptl = huge_pte_lockptr(h, src, src_pte);
4037 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4038 entry = huge_ptep_get(src_pte);
4039 if (!pte_same(src_pte_old, entry)) {
4041 /* dst_entry won't change as in child */
4044 hugetlb_install_page(vma, dst_pte, addr, new);
4045 spin_unlock(src_ptl);
4046 spin_unlock(dst_ptl);
4052 * No need to notify as we are downgrading page
4053 * table protection not changing it to point
4056 * See Documentation/vm/mmu_notifier.rst
4058 huge_ptep_set_wrprotect(src, addr, src_pte);
4061 page_dup_rmap(ptepage, true);
4062 set_huge_pte_at(dst, addr, dst_pte, entry);
4063 hugetlb_count_add(npages, dst);
4065 spin_unlock(src_ptl);
4066 spin_unlock(dst_ptl);
4070 mmu_notifier_invalidate_range_end(&range);
4072 i_mmap_unlock_read(mapping);
4077 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
4078 unsigned long start, unsigned long end,
4079 struct page *ref_page)
4081 struct mm_struct *mm = vma->vm_mm;
4082 unsigned long address;
4087 struct hstate *h = hstate_vma(vma);
4088 unsigned long sz = huge_page_size(h);
4089 struct mmu_notifier_range range;
4091 WARN_ON(!is_vm_hugetlb_page(vma));
4092 BUG_ON(start & ~huge_page_mask(h));
4093 BUG_ON(end & ~huge_page_mask(h));
4096 * This is a hugetlb vma, all the pte entries should point
4099 tlb_change_page_size(tlb, sz);
4100 tlb_start_vma(tlb, vma);
4103 * If sharing possible, alert mmu notifiers of worst case.
4105 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
4107 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4108 mmu_notifier_invalidate_range_start(&range);
4110 for (; address < end; address += sz) {
4111 ptep = huge_pte_offset(mm, address, sz);
4115 ptl = huge_pte_lock(h, mm, ptep);
4116 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
4119 * We just unmapped a page of PMDs by clearing a PUD.
4120 * The caller's TLB flush range should cover this area.
4125 pte = huge_ptep_get(ptep);
4126 if (huge_pte_none(pte)) {
4132 * Migrating hugepage or HWPoisoned hugepage is already
4133 * unmapped and its refcount is dropped, so just clear pte here.
4135 if (unlikely(!pte_present(pte))) {
4136 huge_pte_clear(mm, address, ptep, sz);
4141 page = pte_page(pte);
4143 * If a reference page is supplied, it is because a specific
4144 * page is being unmapped, not a range. Ensure the page we
4145 * are about to unmap is the actual page of interest.
4148 if (page != ref_page) {
4153 * Mark the VMA as having unmapped its page so that
4154 * future faults in this VMA will fail rather than
4155 * looking like data was lost
4157 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4160 pte = huge_ptep_get_and_clear(mm, address, ptep);
4161 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4162 if (huge_pte_dirty(pte))
4163 set_page_dirty(page);
4165 hugetlb_count_sub(pages_per_huge_page(h), mm);
4166 page_remove_rmap(page, true);
4169 tlb_remove_page_size(tlb, page, huge_page_size(h));
4171 * Bail out after unmapping reference page if supplied
4176 mmu_notifier_invalidate_range_end(&range);
4177 tlb_end_vma(tlb, vma);
4180 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4181 struct vm_area_struct *vma, unsigned long start,
4182 unsigned long end, struct page *ref_page)
4184 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4187 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4188 * test will fail on a vma being torn down, and not grab a page table
4189 * on its way out. We're lucky that the flag has such an appropriate
4190 * name, and can in fact be safely cleared here. We could clear it
4191 * before the __unmap_hugepage_range above, but all that's necessary
4192 * is to clear it before releasing the i_mmap_rwsem. This works
4193 * because in the context this is called, the VMA is about to be
4194 * destroyed and the i_mmap_rwsem is held.
4196 vma->vm_flags &= ~VM_MAYSHARE;
4199 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4200 unsigned long end, struct page *ref_page)
4202 struct mmu_gather tlb;
4204 tlb_gather_mmu(&tlb, vma->vm_mm);
4205 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4206 tlb_finish_mmu(&tlb);
4210 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4211 * mapping it owns the reserve page for. The intention is to unmap the page
4212 * from other VMAs and let the children be SIGKILLed if they are faulting the
4215 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4216 struct page *page, unsigned long address)
4218 struct hstate *h = hstate_vma(vma);
4219 struct vm_area_struct *iter_vma;
4220 struct address_space *mapping;
4224 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4225 * from page cache lookup which is in HPAGE_SIZE units.
4227 address = address & huge_page_mask(h);
4228 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4230 mapping = vma->vm_file->f_mapping;
4233 * Take the mapping lock for the duration of the table walk. As
4234 * this mapping should be shared between all the VMAs,
4235 * __unmap_hugepage_range() is called as the lock is already held
4237 i_mmap_lock_write(mapping);
4238 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4239 /* Do not unmap the current VMA */
4240 if (iter_vma == vma)
4244 * Shared VMAs have their own reserves and do not affect
4245 * MAP_PRIVATE accounting but it is possible that a shared
4246 * VMA is using the same page so check and skip such VMAs.
4248 if (iter_vma->vm_flags & VM_MAYSHARE)
4252 * Unmap the page from other VMAs without their own reserves.
4253 * They get marked to be SIGKILLed if they fault in these
4254 * areas. This is because a future no-page fault on this VMA
4255 * could insert a zeroed page instead of the data existing
4256 * from the time of fork. This would look like data corruption
4258 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4259 unmap_hugepage_range(iter_vma, address,
4260 address + huge_page_size(h), page);
4262 i_mmap_unlock_write(mapping);
4266 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4267 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4268 * cannot race with other handlers or page migration.
4269 * Keep the pte_same checks anyway to make transition from the mutex easier.
4271 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4272 unsigned long address, pte_t *ptep,
4273 struct page *pagecache_page, spinlock_t *ptl)
4276 struct hstate *h = hstate_vma(vma);
4277 struct page *old_page, *new_page;
4278 int outside_reserve = 0;
4280 unsigned long haddr = address & huge_page_mask(h);
4281 struct mmu_notifier_range range;
4283 pte = huge_ptep_get(ptep);
4284 old_page = pte_page(pte);
4287 /* If no-one else is actually using this page, avoid the copy
4288 * and just make the page writable */
4289 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4290 page_move_anon_rmap(old_page, vma);
4291 set_huge_ptep_writable(vma, haddr, ptep);
4296 * If the process that created a MAP_PRIVATE mapping is about to
4297 * perform a COW due to a shared page count, attempt to satisfy
4298 * the allocation without using the existing reserves. The pagecache
4299 * page is used to determine if the reserve at this address was
4300 * consumed or not. If reserves were used, a partial faulted mapping
4301 * at the time of fork() could consume its reserves on COW instead
4302 * of the full address range.
4304 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4305 old_page != pagecache_page)
4306 outside_reserve = 1;
4311 * Drop page table lock as buddy allocator may be called. It will
4312 * be acquired again before returning to the caller, as expected.
4315 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4317 if (IS_ERR(new_page)) {
4319 * If a process owning a MAP_PRIVATE mapping fails to COW,
4320 * it is due to references held by a child and an insufficient
4321 * huge page pool. To guarantee the original mappers
4322 * reliability, unmap the page from child processes. The child
4323 * may get SIGKILLed if it later faults.
4325 if (outside_reserve) {
4326 struct address_space *mapping = vma->vm_file->f_mapping;
4331 BUG_ON(huge_pte_none(pte));
4333 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4334 * unmapping. unmapping needs to hold i_mmap_rwsem
4335 * in write mode. Dropping i_mmap_rwsem in read mode
4336 * here is OK as COW mappings do not interact with
4339 * Reacquire both after unmap operation.
4341 idx = vma_hugecache_offset(h, vma, haddr);
4342 hash = hugetlb_fault_mutex_hash(mapping, idx);
4343 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4344 i_mmap_unlock_read(mapping);
4346 unmap_ref_private(mm, vma, old_page, haddr);
4348 i_mmap_lock_read(mapping);
4349 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4351 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4353 pte_same(huge_ptep_get(ptep), pte)))
4354 goto retry_avoidcopy;
4356 * race occurs while re-acquiring page table
4357 * lock, and our job is done.
4362 ret = vmf_error(PTR_ERR(new_page));
4363 goto out_release_old;
4367 * When the original hugepage is shared one, it does not have
4368 * anon_vma prepared.
4370 if (unlikely(anon_vma_prepare(vma))) {
4372 goto out_release_all;
4375 copy_user_huge_page(new_page, old_page, address, vma,
4376 pages_per_huge_page(h));
4377 __SetPageUptodate(new_page);
4379 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4380 haddr + huge_page_size(h));
4381 mmu_notifier_invalidate_range_start(&range);
4384 * Retake the page table lock to check for racing updates
4385 * before the page tables are altered
4388 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4389 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4390 ClearHPageRestoreReserve(new_page);
4393 huge_ptep_clear_flush(vma, haddr, ptep);
4394 mmu_notifier_invalidate_range(mm, range.start, range.end);
4395 set_huge_pte_at(mm, haddr, ptep,
4396 make_huge_pte(vma, new_page, 1));
4397 page_remove_rmap(old_page, true);
4398 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4399 SetHPageMigratable(new_page);
4400 /* Make the old page be freed below */
4401 new_page = old_page;
4404 mmu_notifier_invalidate_range_end(&range);
4406 restore_reserve_on_error(h, vma, haddr, new_page);
4411 spin_lock(ptl); /* Caller expects lock to be held */
4415 /* Return the pagecache page at a given address within a VMA */
4416 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4417 struct vm_area_struct *vma, unsigned long address)
4419 struct address_space *mapping;
4422 mapping = vma->vm_file->f_mapping;
4423 idx = vma_hugecache_offset(h, vma, address);
4425 return find_lock_page(mapping, idx);
4429 * Return whether there is a pagecache page to back given address within VMA.
4430 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4432 static bool hugetlbfs_pagecache_present(struct hstate *h,
4433 struct vm_area_struct *vma, unsigned long address)
4435 struct address_space *mapping;
4439 mapping = vma->vm_file->f_mapping;
4440 idx = vma_hugecache_offset(h, vma, address);
4442 page = find_get_page(mapping, idx);
4445 return page != NULL;
4448 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4451 struct inode *inode = mapping->host;
4452 struct hstate *h = hstate_inode(inode);
4453 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4457 ClearHPageRestoreReserve(page);
4460 * set page dirty so that it will not be removed from cache/file
4461 * by non-hugetlbfs specific code paths.
4463 set_page_dirty(page);
4465 spin_lock(&inode->i_lock);
4466 inode->i_blocks += blocks_per_huge_page(h);
4467 spin_unlock(&inode->i_lock);
4471 static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
4472 struct address_space *mapping,
4475 unsigned long haddr,
4476 unsigned long reason)
4480 struct vm_fault vmf = {
4486 * Hard to debug if it ends up being
4487 * used by a callee that assumes
4488 * something about the other
4489 * uninitialized fields... same as in
4495 * hugetlb_fault_mutex and i_mmap_rwsem must be
4496 * dropped before handling userfault. Reacquire
4497 * after handling fault to make calling code simpler.
4499 hash = hugetlb_fault_mutex_hash(mapping, idx);
4500 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4501 i_mmap_unlock_read(mapping);
4502 ret = handle_userfault(&vmf, reason);
4503 i_mmap_lock_read(mapping);
4504 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4509 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4510 struct vm_area_struct *vma,
4511 struct address_space *mapping, pgoff_t idx,
4512 unsigned long address, pte_t *ptep, unsigned int flags)
4514 struct hstate *h = hstate_vma(vma);
4515 vm_fault_t ret = VM_FAULT_SIGBUS;
4521 unsigned long haddr = address & huge_page_mask(h);
4522 bool new_page = false;
4525 * Currently, we are forced to kill the process in the event the
4526 * original mapper has unmapped pages from the child due to a failed
4527 * COW. Warn that such a situation has occurred as it may not be obvious
4529 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4530 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4536 * We can not race with truncation due to holding i_mmap_rwsem.
4537 * i_size is modified when holding i_mmap_rwsem, so check here
4538 * once for faults beyond end of file.
4540 size = i_size_read(mapping->host) >> huge_page_shift(h);
4545 page = find_lock_page(mapping, idx);
4547 /* Check for page in userfault range */
4548 if (userfaultfd_missing(vma)) {
4549 ret = hugetlb_handle_userfault(vma, mapping, idx,
4555 page = alloc_huge_page(vma, haddr, 0);
4558 * Returning error will result in faulting task being
4559 * sent SIGBUS. The hugetlb fault mutex prevents two
4560 * tasks from racing to fault in the same page which
4561 * could result in false unable to allocate errors.
4562 * Page migration does not take the fault mutex, but
4563 * does a clear then write of pte's under page table
4564 * lock. Page fault code could race with migration,
4565 * notice the clear pte and try to allocate a page
4566 * here. Before returning error, get ptl and make
4567 * sure there really is no pte entry.
4569 ptl = huge_pte_lock(h, mm, ptep);
4571 if (huge_pte_none(huge_ptep_get(ptep)))
4572 ret = vmf_error(PTR_ERR(page));
4576 clear_huge_page(page, address, pages_per_huge_page(h));
4577 __SetPageUptodate(page);
4580 if (vma->vm_flags & VM_MAYSHARE) {
4581 int err = huge_add_to_page_cache(page, mapping, idx);
4590 if (unlikely(anon_vma_prepare(vma))) {
4592 goto backout_unlocked;
4598 * If memory error occurs between mmap() and fault, some process
4599 * don't have hwpoisoned swap entry for errored virtual address.
4600 * So we need to block hugepage fault by PG_hwpoison bit check.
4602 if (unlikely(PageHWPoison(page))) {
4603 ret = VM_FAULT_HWPOISON_LARGE |
4604 VM_FAULT_SET_HINDEX(hstate_index(h));
4605 goto backout_unlocked;
4608 /* Check for page in userfault range. */
4609 if (userfaultfd_minor(vma)) {
4612 ret = hugetlb_handle_userfault(vma, mapping, idx,
4620 * If we are going to COW a private mapping later, we examine the
4621 * pending reservations for this page now. This will ensure that
4622 * any allocations necessary to record that reservation occur outside
4625 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4626 if (vma_needs_reservation(h, vma, haddr) < 0) {
4628 goto backout_unlocked;
4630 /* Just decrements count, does not deallocate */
4631 vma_end_reservation(h, vma, haddr);
4634 ptl = huge_pte_lock(h, mm, ptep);
4636 if (!huge_pte_none(huge_ptep_get(ptep)))
4640 ClearHPageRestoreReserve(page);
4641 hugepage_add_new_anon_rmap(page, vma, haddr);
4643 page_dup_rmap(page, true);
4644 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4645 && (vma->vm_flags & VM_SHARED)));
4646 set_huge_pte_at(mm, haddr, ptep, new_pte);
4648 hugetlb_count_add(pages_per_huge_page(h), mm);
4649 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4650 /* Optimization, do the COW without a second fault */
4651 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4657 * Only set HPageMigratable in newly allocated pages. Existing pages
4658 * found in the pagecache may not have HPageMigratableset if they have
4659 * been isolated for migration.
4662 SetHPageMigratable(page);
4672 restore_reserve_on_error(h, vma, haddr, page);
4678 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4680 unsigned long key[2];
4683 key[0] = (unsigned long) mapping;
4686 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4688 return hash & (num_fault_mutexes - 1);
4692 * For uniprocessor systems we always use a single mutex, so just
4693 * return 0 and avoid the hashing overhead.
4695 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4701 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4702 unsigned long address, unsigned int flags)
4709 struct page *page = NULL;
4710 struct page *pagecache_page = NULL;
4711 struct hstate *h = hstate_vma(vma);
4712 struct address_space *mapping;
4713 int need_wait_lock = 0;
4714 unsigned long haddr = address & huge_page_mask(h);
4716 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4719 * Since we hold no locks, ptep could be stale. That is
4720 * OK as we are only making decisions based on content and
4721 * not actually modifying content here.
4723 entry = huge_ptep_get(ptep);
4724 if (unlikely(is_hugetlb_entry_migration(entry))) {
4725 migration_entry_wait_huge(vma, mm, ptep);
4727 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4728 return VM_FAULT_HWPOISON_LARGE |
4729 VM_FAULT_SET_HINDEX(hstate_index(h));
4733 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4734 * until finished with ptep. This serves two purposes:
4735 * 1) It prevents huge_pmd_unshare from being called elsewhere
4736 * and making the ptep no longer valid.
4737 * 2) It synchronizes us with i_size modifications during truncation.
4739 * ptep could have already be assigned via huge_pte_offset. That
4740 * is OK, as huge_pte_alloc will return the same value unless
4741 * something has changed.
4743 mapping = vma->vm_file->f_mapping;
4744 i_mmap_lock_read(mapping);
4745 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
4747 i_mmap_unlock_read(mapping);
4748 return VM_FAULT_OOM;
4752 * Serialize hugepage allocation and instantiation, so that we don't
4753 * get spurious allocation failures if two CPUs race to instantiate
4754 * the same page in the page cache.
4756 idx = vma_hugecache_offset(h, vma, haddr);
4757 hash = hugetlb_fault_mutex_hash(mapping, idx);
4758 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4760 entry = huge_ptep_get(ptep);
4761 if (huge_pte_none(entry)) {
4762 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4769 * entry could be a migration/hwpoison entry at this point, so this
4770 * check prevents the kernel from going below assuming that we have
4771 * an active hugepage in pagecache. This goto expects the 2nd page
4772 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4773 * properly handle it.
4775 if (!pte_present(entry))
4779 * If we are going to COW the mapping later, we examine the pending
4780 * reservations for this page now. This will ensure that any
4781 * allocations necessary to record that reservation occur outside the
4782 * spinlock. For private mappings, we also lookup the pagecache
4783 * page now as it is used to determine if a reservation has been
4786 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4787 if (vma_needs_reservation(h, vma, haddr) < 0) {
4791 /* Just decrements count, does not deallocate */
4792 vma_end_reservation(h, vma, haddr);
4794 if (!(vma->vm_flags & VM_MAYSHARE))
4795 pagecache_page = hugetlbfs_pagecache_page(h,
4799 ptl = huge_pte_lock(h, mm, ptep);
4801 /* Check for a racing update before calling hugetlb_cow */
4802 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4806 * hugetlb_cow() requires page locks of pte_page(entry) and
4807 * pagecache_page, so here we need take the former one
4808 * when page != pagecache_page or !pagecache_page.
4810 page = pte_page(entry);
4811 if (page != pagecache_page)
4812 if (!trylock_page(page)) {
4819 if (flags & FAULT_FLAG_WRITE) {
4820 if (!huge_pte_write(entry)) {
4821 ret = hugetlb_cow(mm, vma, address, ptep,
4822 pagecache_page, ptl);
4825 entry = huge_pte_mkdirty(entry);
4827 entry = pte_mkyoung(entry);
4828 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4829 flags & FAULT_FLAG_WRITE))
4830 update_mmu_cache(vma, haddr, ptep);
4832 if (page != pagecache_page)
4838 if (pagecache_page) {
4839 unlock_page(pagecache_page);
4840 put_page(pagecache_page);
4843 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4844 i_mmap_unlock_read(mapping);
4846 * Generally it's safe to hold refcount during waiting page lock. But
4847 * here we just wait to defer the next page fault to avoid busy loop and
4848 * the page is not used after unlocked before returning from the current
4849 * page fault. So we are safe from accessing freed page, even if we wait
4850 * here without taking refcount.
4853 wait_on_page_locked(page);
4857 #ifdef CONFIG_USERFAULTFD
4859 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4860 * modifications for huge pages.
4862 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4864 struct vm_area_struct *dst_vma,
4865 unsigned long dst_addr,
4866 unsigned long src_addr,
4867 enum mcopy_atomic_mode mode,
4868 struct page **pagep)
4870 bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
4871 struct address_space *mapping;
4874 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4875 struct hstate *h = hstate_vma(dst_vma);
4882 mapping = dst_vma->vm_file->f_mapping;
4883 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4887 page = find_lock_page(mapping, idx);
4890 } else if (!*pagep) {
4892 page = alloc_huge_page(dst_vma, dst_addr, 0);
4896 ret = copy_huge_page_from_user(page,
4897 (const void __user *) src_addr,
4898 pages_per_huge_page(h), false);
4900 /* fallback to copy_from_user outside mmap_lock */
4901 if (unlikely(ret)) {
4904 /* don't free the page */
4913 * The memory barrier inside __SetPageUptodate makes sure that
4914 * preceding stores to the page contents become visible before
4915 * the set_pte_at() write.
4917 __SetPageUptodate(page);
4919 /* Add shared, newly allocated pages to the page cache. */
4920 if (vm_shared && !is_continue) {
4921 size = i_size_read(mapping->host) >> huge_page_shift(h);
4924 goto out_release_nounlock;
4927 * Serialization between remove_inode_hugepages() and
4928 * huge_add_to_page_cache() below happens through the
4929 * hugetlb_fault_mutex_table that here must be hold by
4932 ret = huge_add_to_page_cache(page, mapping, idx);
4934 goto out_release_nounlock;
4937 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4941 * Recheck the i_size after holding PT lock to make sure not
4942 * to leave any page mapped (as page_mapped()) beyond the end
4943 * of the i_size (remove_inode_hugepages() is strict about
4944 * enforcing that). If we bail out here, we'll also leave a
4945 * page in the radix tree in the vm_shared case beyond the end
4946 * of the i_size, but remove_inode_hugepages() will take care
4947 * of it as soon as we drop the hugetlb_fault_mutex_table.
4949 size = i_size_read(mapping->host) >> huge_page_shift(h);
4952 goto out_release_unlock;
4955 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4956 goto out_release_unlock;
4959 page_dup_rmap(page, true);
4961 ClearHPageRestoreReserve(page);
4962 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4965 /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
4966 if (is_continue && !vm_shared)
4969 writable = dst_vma->vm_flags & VM_WRITE;
4971 _dst_pte = make_huge_pte(dst_vma, page, writable);
4973 _dst_pte = huge_pte_mkdirty(_dst_pte);
4974 _dst_pte = pte_mkyoung(_dst_pte);
4976 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4978 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4979 dst_vma->vm_flags & VM_WRITE);
4980 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4982 /* No need to invalidate - it was non-present before */
4983 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4987 SetHPageMigratable(page);
4988 if (vm_shared || is_continue)
4995 if (vm_shared || is_continue)
4997 out_release_nounlock:
5001 #endif /* CONFIG_USERFAULTFD */
5003 static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
5004 int refs, struct page **pages,
5005 struct vm_area_struct **vmas)
5009 for (nr = 0; nr < refs; nr++) {
5011 pages[nr] = mem_map_offset(page, nr);
5017 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
5018 struct page **pages, struct vm_area_struct **vmas,
5019 unsigned long *position, unsigned long *nr_pages,
5020 long i, unsigned int flags, int *locked)
5022 unsigned long pfn_offset;
5023 unsigned long vaddr = *position;
5024 unsigned long remainder = *nr_pages;
5025 struct hstate *h = hstate_vma(vma);
5026 int err = -EFAULT, refs;
5028 while (vaddr < vma->vm_end && remainder) {
5030 spinlock_t *ptl = NULL;
5035 * If we have a pending SIGKILL, don't keep faulting pages and
5036 * potentially allocating memory.
5038 if (fatal_signal_pending(current)) {
5044 * Some archs (sparc64, sh*) have multiple pte_ts to
5045 * each hugepage. We have to make sure we get the
5046 * first, for the page indexing below to work.
5048 * Note that page table lock is not held when pte is null.
5050 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
5053 ptl = huge_pte_lock(h, mm, pte);
5054 absent = !pte || huge_pte_none(huge_ptep_get(pte));
5057 * When coredumping, it suits get_dump_page if we just return
5058 * an error where there's an empty slot with no huge pagecache
5059 * to back it. This way, we avoid allocating a hugepage, and
5060 * the sparse dumpfile avoids allocating disk blocks, but its
5061 * huge holes still show up with zeroes where they need to be.
5063 if (absent && (flags & FOLL_DUMP) &&
5064 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
5072 * We need call hugetlb_fault for both hugepages under migration
5073 * (in which case hugetlb_fault waits for the migration,) and
5074 * hwpoisoned hugepages (in which case we need to prevent the
5075 * caller from accessing to them.) In order to do this, we use
5076 * here is_swap_pte instead of is_hugetlb_entry_migration and
5077 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
5078 * both cases, and because we can't follow correct pages
5079 * directly from any kind of swap entries.
5081 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
5082 ((flags & FOLL_WRITE) &&
5083 !huge_pte_write(huge_ptep_get(pte)))) {
5085 unsigned int fault_flags = 0;
5089 if (flags & FOLL_WRITE)
5090 fault_flags |= FAULT_FLAG_WRITE;
5092 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5093 FAULT_FLAG_KILLABLE;
5094 if (flags & FOLL_NOWAIT)
5095 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5096 FAULT_FLAG_RETRY_NOWAIT;
5097 if (flags & FOLL_TRIED) {
5099 * Note: FAULT_FLAG_ALLOW_RETRY and
5100 * FAULT_FLAG_TRIED can co-exist
5102 fault_flags |= FAULT_FLAG_TRIED;
5104 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
5105 if (ret & VM_FAULT_ERROR) {
5106 err = vm_fault_to_errno(ret, flags);
5110 if (ret & VM_FAULT_RETRY) {
5112 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
5116 * VM_FAULT_RETRY must not return an
5117 * error, it will return zero
5120 * No need to update "position" as the
5121 * caller will not check it after
5122 * *nr_pages is set to 0.
5129 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
5130 page = pte_page(huge_ptep_get(pte));
5133 * If subpage information not requested, update counters
5134 * and skip the same_page loop below.
5136 if (!pages && !vmas && !pfn_offset &&
5137 (vaddr + huge_page_size(h) < vma->vm_end) &&
5138 (remainder >= pages_per_huge_page(h))) {
5139 vaddr += huge_page_size(h);
5140 remainder -= pages_per_huge_page(h);
5141 i += pages_per_huge_page(h);
5146 refs = min3(pages_per_huge_page(h) - pfn_offset,
5147 (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
5150 record_subpages_vmas(mem_map_offset(page, pfn_offset),
5152 likely(pages) ? pages + i : NULL,
5153 vmas ? vmas + i : NULL);
5157 * try_grab_compound_head() should always succeed here,
5158 * because: a) we hold the ptl lock, and b) we've just
5159 * checked that the huge page is present in the page
5160 * tables. If the huge page is present, then the tail
5161 * pages must also be present. The ptl prevents the
5162 * head page and tail pages from being rearranged in
5163 * any way. So this page must be available at this
5164 * point, unless the page refcount overflowed:
5166 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
5176 vaddr += (refs << PAGE_SHIFT);
5182 *nr_pages = remainder;
5184 * setting position is actually required only if remainder is
5185 * not zero but it's faster not to add a "if (remainder)"
5193 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5194 unsigned long address, unsigned long end, pgprot_t newprot)
5196 struct mm_struct *mm = vma->vm_mm;
5197 unsigned long start = address;
5200 struct hstate *h = hstate_vma(vma);
5201 unsigned long pages = 0;
5202 bool shared_pmd = false;
5203 struct mmu_notifier_range range;
5206 * In the case of shared PMDs, the area to flush could be beyond
5207 * start/end. Set range.start/range.end to cover the maximum possible
5208 * range if PMD sharing is possible.
5210 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5211 0, vma, mm, start, end);
5212 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5214 BUG_ON(address >= end);
5215 flush_cache_range(vma, range.start, range.end);
5217 mmu_notifier_invalidate_range_start(&range);
5218 i_mmap_lock_write(vma->vm_file->f_mapping);
5219 for (; address < end; address += huge_page_size(h)) {
5221 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5224 ptl = huge_pte_lock(h, mm, ptep);
5225 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5231 pte = huge_ptep_get(ptep);
5232 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5236 if (unlikely(is_hugetlb_entry_migration(pte))) {
5237 swp_entry_t entry = pte_to_swp_entry(pte);
5239 if (is_write_migration_entry(entry)) {
5242 make_migration_entry_read(&entry);
5243 newpte = swp_entry_to_pte(entry);
5244 set_huge_swap_pte_at(mm, address, ptep,
5245 newpte, huge_page_size(h));
5251 if (!huge_pte_none(pte)) {
5254 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5255 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5256 pte = arch_make_huge_pte(pte, vma, NULL, 0);
5257 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5263 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5264 * may have cleared our pud entry and done put_page on the page table:
5265 * once we release i_mmap_rwsem, another task can do the final put_page
5266 * and that page table be reused and filled with junk. If we actually
5267 * did unshare a page of pmds, flush the range corresponding to the pud.
5270 flush_hugetlb_tlb_range(vma, range.start, range.end);
5272 flush_hugetlb_tlb_range(vma, start, end);
5274 * No need to call mmu_notifier_invalidate_range() we are downgrading
5275 * page table protection not changing it to point to a new page.
5277 * See Documentation/vm/mmu_notifier.rst
5279 i_mmap_unlock_write(vma->vm_file->f_mapping);
5280 mmu_notifier_invalidate_range_end(&range);
5282 return pages << h->order;
5285 /* Return true if reservation was successful, false otherwise. */
5286 bool hugetlb_reserve_pages(struct inode *inode,
5288 struct vm_area_struct *vma,
5289 vm_flags_t vm_flags)
5292 struct hstate *h = hstate_inode(inode);
5293 struct hugepage_subpool *spool = subpool_inode(inode);
5294 struct resv_map *resv_map;
5295 struct hugetlb_cgroup *h_cg = NULL;
5296 long gbl_reserve, regions_needed = 0;
5298 /* This should never happen */
5300 VM_WARN(1, "%s called with a negative range\n", __func__);
5305 * Only apply hugepage reservation if asked. At fault time, an
5306 * attempt will be made for VM_NORESERVE to allocate a page
5307 * without using reserves
5309 if (vm_flags & VM_NORESERVE)
5313 * Shared mappings base their reservation on the number of pages that
5314 * are already allocated on behalf of the file. Private mappings need
5315 * to reserve the full area even if read-only as mprotect() may be
5316 * called to make the mapping read-write. Assume !vma is a shm mapping
5318 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5320 * resv_map can not be NULL as hugetlb_reserve_pages is only
5321 * called for inodes for which resv_maps were created (see
5322 * hugetlbfs_get_inode).
5324 resv_map = inode_resv_map(inode);
5326 chg = region_chg(resv_map, from, to, ®ions_needed);
5329 /* Private mapping. */
5330 resv_map = resv_map_alloc();
5336 set_vma_resv_map(vma, resv_map);
5337 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5343 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
5344 chg * pages_per_huge_page(h), &h_cg) < 0)
5347 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5348 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5351 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5355 * There must be enough pages in the subpool for the mapping. If
5356 * the subpool has a minimum size, there may be some global
5357 * reservations already in place (gbl_reserve).
5359 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5360 if (gbl_reserve < 0)
5361 goto out_uncharge_cgroup;
5364 * Check enough hugepages are available for the reservation.
5365 * Hand the pages back to the subpool if there are not
5367 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
5371 * Account for the reservations made. Shared mappings record regions
5372 * that have reservations as they are shared by multiple VMAs.
5373 * When the last VMA disappears, the region map says how much
5374 * the reservation was and the page cache tells how much of
5375 * the reservation was consumed. Private mappings are per-VMA and
5376 * only the consumed reservations are tracked. When the VMA
5377 * disappears, the original reservation is the VMA size and the
5378 * consumed reservations are stored in the map. Hence, nothing
5379 * else has to be done for private mappings here
5381 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5382 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5384 if (unlikely(add < 0)) {
5385 hugetlb_acct_memory(h, -gbl_reserve);
5387 } else if (unlikely(chg > add)) {
5389 * pages in this range were added to the reserve
5390 * map between region_chg and region_add. This
5391 * indicates a race with alloc_huge_page. Adjust
5392 * the subpool and reserve counts modified above
5393 * based on the difference.
5398 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5399 * reference to h_cg->css. See comment below for detail.
5401 hugetlb_cgroup_uncharge_cgroup_rsvd(
5403 (chg - add) * pages_per_huge_page(h), h_cg);
5405 rsv_adjust = hugepage_subpool_put_pages(spool,
5407 hugetlb_acct_memory(h, -rsv_adjust);
5410 * The file_regions will hold their own reference to
5411 * h_cg->css. So we should release the reference held
5412 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5415 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5421 /* put back original number of pages, chg */
5422 (void)hugepage_subpool_put_pages(spool, chg);
5423 out_uncharge_cgroup:
5424 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5425 chg * pages_per_huge_page(h), h_cg);
5427 if (!vma || vma->vm_flags & VM_MAYSHARE)
5428 /* Only call region_abort if the region_chg succeeded but the
5429 * region_add failed or didn't run.
5431 if (chg >= 0 && add < 0)
5432 region_abort(resv_map, from, to, regions_needed);
5433 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5434 kref_put(&resv_map->refs, resv_map_release);
5438 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5441 struct hstate *h = hstate_inode(inode);
5442 struct resv_map *resv_map = inode_resv_map(inode);
5444 struct hugepage_subpool *spool = subpool_inode(inode);
5448 * Since this routine can be called in the evict inode path for all
5449 * hugetlbfs inodes, resv_map could be NULL.
5452 chg = region_del(resv_map, start, end);
5454 * region_del() can fail in the rare case where a region
5455 * must be split and another region descriptor can not be
5456 * allocated. If end == LONG_MAX, it will not fail.
5462 spin_lock(&inode->i_lock);
5463 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5464 spin_unlock(&inode->i_lock);
5467 * If the subpool has a minimum size, the number of global
5468 * reservations to be released may be adjusted.
5470 * Note that !resv_map implies freed == 0. So (chg - freed)
5471 * won't go negative.
5473 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5474 hugetlb_acct_memory(h, -gbl_reserve);
5479 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5480 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5481 struct vm_area_struct *vma,
5482 unsigned long addr, pgoff_t idx)
5484 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5486 unsigned long sbase = saddr & PUD_MASK;
5487 unsigned long s_end = sbase + PUD_SIZE;
5489 /* Allow segments to share if only one is marked locked */
5490 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5491 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5494 * match the virtual addresses, permission and the alignment of the
5497 if (pmd_index(addr) != pmd_index(saddr) ||
5498 vm_flags != svm_flags ||
5499 !range_in_vma(svma, sbase, s_end))
5505 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5507 unsigned long base = addr & PUD_MASK;
5508 unsigned long end = base + PUD_SIZE;
5511 * check on proper vm_flags and page table alignment
5513 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5518 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5520 #ifdef CONFIG_USERFAULTFD
5521 if (uffd_disable_huge_pmd_share(vma))
5524 return vma_shareable(vma, addr);
5528 * Determine if start,end range within vma could be mapped by shared pmd.
5529 * If yes, adjust start and end to cover range associated with possible
5530 * shared pmd mappings.
5532 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5533 unsigned long *start, unsigned long *end)
5535 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5536 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5539 * vma need span at least one aligned PUD size and the start,end range
5540 * must at least partialy within it.
5542 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5543 (*end <= v_start) || (*start >= v_end))
5546 /* Extend the range to be PUD aligned for a worst case scenario */
5547 if (*start > v_start)
5548 *start = ALIGN_DOWN(*start, PUD_SIZE);
5551 *end = ALIGN(*end, PUD_SIZE);
5555 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5556 * and returns the corresponding pte. While this is not necessary for the
5557 * !shared pmd case because we can allocate the pmd later as well, it makes the
5558 * code much cleaner.
5560 * This routine must be called with i_mmap_rwsem held in at least read mode if
5561 * sharing is possible. For hugetlbfs, this prevents removal of any page
5562 * table entries associated with the address space. This is important as we
5563 * are setting up sharing based on existing page table entries (mappings).
5565 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5566 * huge_pte_alloc know that sharing is not possible and do not take
5567 * i_mmap_rwsem as a performance optimization. This is handled by the
5568 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5569 * only required for subsequent processing.
5571 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5572 unsigned long addr, pud_t *pud)
5574 struct address_space *mapping = vma->vm_file->f_mapping;
5575 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5577 struct vm_area_struct *svma;
5578 unsigned long saddr;
5583 i_mmap_assert_locked(mapping);
5584 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5588 saddr = page_table_shareable(svma, vma, addr, idx);
5590 spte = huge_pte_offset(svma->vm_mm, saddr,
5591 vma_mmu_pagesize(svma));
5593 get_page(virt_to_page(spte));
5602 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5603 if (pud_none(*pud)) {
5604 pud_populate(mm, pud,
5605 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5608 put_page(virt_to_page(spte));
5612 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5617 * unmap huge page backed by shared pte.
5619 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5620 * indicated by page_count > 1, unmap is achieved by clearing pud and
5621 * decrementing the ref count. If count == 1, the pte page is not shared.
5623 * Called with page table lock held and i_mmap_rwsem held in write mode.
5625 * returns: 1 successfully unmapped a shared pte page
5626 * 0 the underlying pte page is not shared, or it is the last user
5628 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5629 unsigned long *addr, pte_t *ptep)
5631 pgd_t *pgd = pgd_offset(mm, *addr);
5632 p4d_t *p4d = p4d_offset(pgd, *addr);
5633 pud_t *pud = pud_offset(p4d, *addr);
5635 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5636 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5637 if (page_count(virt_to_page(ptep)) == 1)
5641 put_page(virt_to_page(ptep));
5643 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5647 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5648 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5649 unsigned long addr, pud_t *pud)
5654 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5655 unsigned long *addr, pte_t *ptep)
5660 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5661 unsigned long *start, unsigned long *end)
5665 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5669 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5671 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5672 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
5673 unsigned long addr, unsigned long sz)
5680 pgd = pgd_offset(mm, addr);
5681 p4d = p4d_alloc(mm, pgd, addr);
5684 pud = pud_alloc(mm, p4d, addr);
5686 if (sz == PUD_SIZE) {
5689 BUG_ON(sz != PMD_SIZE);
5690 if (want_pmd_share(vma, addr) && pud_none(*pud))
5691 pte = huge_pmd_share(mm, vma, addr, pud);
5693 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5696 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5702 * huge_pte_offset() - Walk the page table to resolve the hugepage
5703 * entry at address @addr
5705 * Return: Pointer to page table entry (PUD or PMD) for
5706 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5707 * size @sz doesn't match the hugepage size at this level of the page
5710 pte_t *huge_pte_offset(struct mm_struct *mm,
5711 unsigned long addr, unsigned long sz)
5718 pgd = pgd_offset(mm, addr);
5719 if (!pgd_present(*pgd))
5721 p4d = p4d_offset(pgd, addr);
5722 if (!p4d_present(*p4d))
5725 pud = pud_offset(p4d, addr);
5727 /* must be pud huge, non-present or none */
5728 return (pte_t *)pud;
5729 if (!pud_present(*pud))
5731 /* must have a valid entry and size to go further */
5733 pmd = pmd_offset(pud, addr);
5734 /* must be pmd huge, non-present or none */
5735 return (pte_t *)pmd;
5738 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5741 * These functions are overwritable if your architecture needs its own
5744 struct page * __weak
5745 follow_huge_addr(struct mm_struct *mm, unsigned long address,
5748 return ERR_PTR(-EINVAL);
5751 struct page * __weak
5752 follow_huge_pd(struct vm_area_struct *vma,
5753 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5755 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5759 struct page * __weak
5760 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5761 pmd_t *pmd, int flags)
5763 struct page *page = NULL;
5767 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5768 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5769 (FOLL_PIN | FOLL_GET)))
5773 ptl = pmd_lockptr(mm, pmd);
5776 * make sure that the address range covered by this pmd is not
5777 * unmapped from other threads.
5779 if (!pmd_huge(*pmd))
5781 pte = huge_ptep_get((pte_t *)pmd);
5782 if (pte_present(pte)) {
5783 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5785 * try_grab_page() should always succeed here, because: a) we
5786 * hold the pmd (ptl) lock, and b) we've just checked that the
5787 * huge pmd (head) page is present in the page tables. The ptl
5788 * prevents the head page and tail pages from being rearranged
5789 * in any way. So this page must be available at this point,
5790 * unless the page refcount overflowed:
5792 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5797 if (is_hugetlb_entry_migration(pte)) {
5799 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5803 * hwpoisoned entry is treated as no_page_table in
5804 * follow_page_mask().
5812 struct page * __weak
5813 follow_huge_pud(struct mm_struct *mm, unsigned long address,
5814 pud_t *pud, int flags)
5816 if (flags & (FOLL_GET | FOLL_PIN))
5819 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5822 struct page * __weak
5823 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5825 if (flags & (FOLL_GET | FOLL_PIN))
5828 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5831 bool isolate_huge_page(struct page *page, struct list_head *list)
5835 spin_lock_irq(&hugetlb_lock);
5836 if (!PageHeadHuge(page) ||
5837 !HPageMigratable(page) ||
5838 !get_page_unless_zero(page)) {
5842 ClearHPageMigratable(page);
5843 list_move_tail(&page->lru, list);
5845 spin_unlock_irq(&hugetlb_lock);
5849 void putback_active_hugepage(struct page *page)
5851 spin_lock_irq(&hugetlb_lock);
5852 SetHPageMigratable(page);
5853 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5854 spin_unlock_irq(&hugetlb_lock);
5858 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5860 struct hstate *h = page_hstate(oldpage);
5862 hugetlb_cgroup_migrate(oldpage, newpage);
5863 set_page_owner_migrate_reason(newpage, reason);
5866 * transfer temporary state of the new huge page. This is
5867 * reverse to other transitions because the newpage is going to
5868 * be final while the old one will be freed so it takes over
5869 * the temporary status.
5871 * Also note that we have to transfer the per-node surplus state
5872 * here as well otherwise the global surplus count will not match
5875 if (HPageTemporary(newpage)) {
5876 int old_nid = page_to_nid(oldpage);
5877 int new_nid = page_to_nid(newpage);
5879 SetHPageTemporary(oldpage);
5880 ClearHPageTemporary(newpage);
5883 * There is no need to transfer the per-node surplus state
5884 * when we do not cross the node.
5886 if (new_nid == old_nid)
5888 spin_lock_irq(&hugetlb_lock);
5889 if (h->surplus_huge_pages_node[old_nid]) {
5890 h->surplus_huge_pages_node[old_nid]--;
5891 h->surplus_huge_pages_node[new_nid]++;
5893 spin_unlock_irq(&hugetlb_lock);
5898 * This function will unconditionally remove all the shared pmd pgtable entries
5899 * within the specific vma for a hugetlbfs memory range.
5901 void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
5903 struct hstate *h = hstate_vma(vma);
5904 unsigned long sz = huge_page_size(h);
5905 struct mm_struct *mm = vma->vm_mm;
5906 struct mmu_notifier_range range;
5907 unsigned long address, start, end;
5911 if (!(vma->vm_flags & VM_MAYSHARE))
5914 start = ALIGN(vma->vm_start, PUD_SIZE);
5915 end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5921 * No need to call adjust_range_if_pmd_sharing_possible(), because
5922 * we have already done the PUD_SIZE alignment.
5924 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
5926 mmu_notifier_invalidate_range_start(&range);
5927 i_mmap_lock_write(vma->vm_file->f_mapping);
5928 for (address = start; address < end; address += PUD_SIZE) {
5929 unsigned long tmp = address;
5931 ptep = huge_pte_offset(mm, address, sz);
5934 ptl = huge_pte_lock(h, mm, ptep);
5935 /* We don't want 'address' to be changed */
5936 huge_pmd_unshare(mm, vma, &tmp, ptep);
5939 flush_hugetlb_tlb_range(vma, start, end);
5940 i_mmap_unlock_write(vma->vm_file->f_mapping);
5942 * No need to call mmu_notifier_invalidate_range(), see
5943 * Documentation/vm/mmu_notifier.rst.
5945 mmu_notifier_invalidate_range_end(&range);
5949 static bool cma_reserve_called __initdata;
5951 static int __init cmdline_parse_hugetlb_cma(char *p)
5953 hugetlb_cma_size = memparse(p, &p);
5957 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
5959 void __init hugetlb_cma_reserve(int order)
5961 unsigned long size, reserved, per_node;
5964 cma_reserve_called = true;
5966 if (!hugetlb_cma_size)
5969 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
5970 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5971 (PAGE_SIZE << order) / SZ_1M);
5976 * If 3 GB area is requested on a machine with 4 numa nodes,
5977 * let's allocate 1 GB on first three nodes and ignore the last one.
5979 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
5980 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5981 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
5984 for_each_node_state(nid, N_ONLINE) {
5986 char name[CMA_MAX_NAME];
5988 size = min(per_node, hugetlb_cma_size - reserved);
5989 size = round_up(size, PAGE_SIZE << order);
5991 snprintf(name, sizeof(name), "hugetlb%d", nid);
5992 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5994 &hugetlb_cma[nid], nid);
5996 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
6002 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
6005 if (reserved >= hugetlb_cma_size)
6010 void __init hugetlb_cma_check(void)
6012 if (!hugetlb_cma_size || cma_reserve_called)
6015 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
6018 #endif /* CONFIG_CMA */