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/mmdebug.h>
23 #include <linux/sched/signal.h>
24 #include <linux/rmap.h>
25 #include <linux/string_helpers.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
28 #include <linux/jhash.h>
29 #include <linux/numa.h>
30 #include <linux/llist.h>
33 #include <asm/pgtable.h>
37 #include <linux/hugetlb.h>
38 #include <linux/hugetlb_cgroup.h>
39 #include <linux/node.h>
40 #include <linux/userfaultfd_k.h>
41 #include <linux/page_owner.h>
44 int hugetlb_max_hstate __read_mostly;
45 unsigned int default_hstate_idx;
46 struct hstate hstates[HUGE_MAX_HSTATE];
48 * Minimum page order among possible hugepage sizes, set to a proper value
51 static unsigned int minimum_order __read_mostly = UINT_MAX;
53 __initdata LIST_HEAD(huge_boot_pages);
55 /* for command line parsing */
56 static struct hstate * __initdata parsed_hstate;
57 static unsigned long __initdata default_hstate_max_huge_pages;
58 static unsigned long __initdata default_hstate_size;
59 static bool __initdata parsed_valid_hugepagesz = true;
62 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
63 * free_huge_pages, and surplus_huge_pages.
65 DEFINE_SPINLOCK(hugetlb_lock);
68 * Serializes faults on the same logical page. This is used to
69 * prevent spurious OOMs when the hugepage pool is fully utilized.
71 static int num_fault_mutexes;
72 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
74 /* Forward declaration */
75 static int hugetlb_acct_memory(struct hstate *h, long delta);
77 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
79 bool free = (spool->count == 0) && (spool->used_hpages == 0);
81 spin_unlock(&spool->lock);
83 /* If no pages are used, and no other handles to the subpool
84 * remain, give up any reservations mased on minimum size and
87 if (spool->min_hpages != -1)
88 hugetlb_acct_memory(spool->hstate,
94 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
97 struct hugepage_subpool *spool;
99 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
103 spin_lock_init(&spool->lock);
105 spool->max_hpages = max_hpages;
107 spool->min_hpages = min_hpages;
109 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
113 spool->rsv_hpages = min_hpages;
118 void hugepage_put_subpool(struct hugepage_subpool *spool)
120 spin_lock(&spool->lock);
121 BUG_ON(!spool->count);
123 unlock_or_release_subpool(spool);
127 * Subpool accounting for allocating and reserving pages.
128 * Return -ENOMEM if there are not enough resources to satisfy the
129 * the request. Otherwise, return the number of pages by which the
130 * global pools must be adjusted (upward). The returned value may
131 * only be different than the passed value (delta) in the case where
132 * a subpool minimum size must be manitained.
134 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
142 spin_lock(&spool->lock);
144 if (spool->max_hpages != -1) { /* maximum size accounting */
145 if ((spool->used_hpages + delta) <= spool->max_hpages)
146 spool->used_hpages += delta;
153 /* minimum size accounting */
154 if (spool->min_hpages != -1 && spool->rsv_hpages) {
155 if (delta > spool->rsv_hpages) {
157 * Asking for more reserves than those already taken on
158 * behalf of subpool. Return difference.
160 ret = delta - spool->rsv_hpages;
161 spool->rsv_hpages = 0;
163 ret = 0; /* reserves already accounted for */
164 spool->rsv_hpages -= delta;
169 spin_unlock(&spool->lock);
174 * Subpool accounting for freeing and unreserving pages.
175 * Return the number of global page reservations that must be dropped.
176 * The return value may only be different than the passed value (delta)
177 * in the case where a subpool minimum size must be maintained.
179 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
187 spin_lock(&spool->lock);
189 if (spool->max_hpages != -1) /* maximum size accounting */
190 spool->used_hpages -= delta;
192 /* minimum size accounting */
193 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
194 if (spool->rsv_hpages + delta <= spool->min_hpages)
197 ret = spool->rsv_hpages + delta - spool->min_hpages;
199 spool->rsv_hpages += delta;
200 if (spool->rsv_hpages > spool->min_hpages)
201 spool->rsv_hpages = spool->min_hpages;
205 * If hugetlbfs_put_super couldn't free spool due to an outstanding
206 * quota reference, free it now.
208 unlock_or_release_subpool(spool);
213 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
215 return HUGETLBFS_SB(inode->i_sb)->spool;
218 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
220 return subpool_inode(file_inode(vma->vm_file));
223 /* Helper that removes a struct file_region from the resv_map cache and returns
226 static struct file_region *
227 get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
229 struct file_region *nrg = NULL;
231 VM_BUG_ON(resv->region_cache_count <= 0);
233 resv->region_cache_count--;
234 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
236 list_del(&nrg->link);
244 static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
245 struct file_region *rg)
247 #ifdef CONFIG_CGROUP_HUGETLB
248 nrg->reservation_counter = rg->reservation_counter;
255 /* Helper that records hugetlb_cgroup uncharge info. */
256 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
258 struct resv_map *resv,
259 struct file_region *nrg)
261 #ifdef CONFIG_CGROUP_HUGETLB
263 nrg->reservation_counter =
264 &h_cg->rsvd_hugepage[hstate_index(h)];
265 nrg->css = &h_cg->css;
266 if (!resv->pages_per_hpage)
267 resv->pages_per_hpage = pages_per_huge_page(h);
268 /* pages_per_hpage should be the same for all entries in
271 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
273 nrg->reservation_counter = NULL;
279 static bool has_same_uncharge_info(struct file_region *rg,
280 struct file_region *org)
282 #ifdef CONFIG_CGROUP_HUGETLB
284 rg->reservation_counter == org->reservation_counter &&
292 static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
294 struct file_region *nrg = NULL, *prg = NULL;
296 prg = list_prev_entry(rg, link);
297 if (&prg->link != &resv->regions && prg->to == rg->from &&
298 has_same_uncharge_info(prg, rg)) {
304 coalesce_file_region(resv, prg);
308 nrg = list_next_entry(rg, link);
309 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
310 has_same_uncharge_info(nrg, rg)) {
311 nrg->from = rg->from;
316 coalesce_file_region(resv, nrg);
321 /* Must be called with resv->lock held. Calling this with count_only == true
322 * will count the number of pages to be added but will not modify the linked
323 * list. If regions_needed != NULL and count_only == true, then regions_needed
324 * will indicate the number of file_regions needed in the cache to carry out to
325 * add the regions for this range.
327 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
328 struct hugetlb_cgroup *h_cg,
329 struct hstate *h, long *regions_needed,
333 struct list_head *head = &resv->regions;
334 long last_accounted_offset = f;
335 struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
340 /* In this loop, we essentially handle an entry for the range
341 * [last_accounted_offset, rg->from), at every iteration, with some
344 list_for_each_entry_safe(rg, trg, head, link) {
345 /* Skip irrelevant regions that start before our range. */
347 /* If this region ends after the last accounted offset,
348 * then we need to update last_accounted_offset.
350 if (rg->to > last_accounted_offset)
351 last_accounted_offset = rg->to;
355 /* When we find a region that starts beyond our range, we've
361 /* Add an entry for last_accounted_offset -> rg->from, and
362 * update last_accounted_offset.
364 if (rg->from > last_accounted_offset) {
365 add += rg->from - last_accounted_offset;
367 nrg = get_file_region_entry_from_cache(
368 resv, last_accounted_offset, rg->from);
369 record_hugetlb_cgroup_uncharge_info(h_cg, h,
371 list_add(&nrg->link, rg->link.prev);
372 coalesce_file_region(resv, nrg);
373 } else if (regions_needed)
374 *regions_needed += 1;
377 last_accounted_offset = rg->to;
380 /* Handle the case where our range extends beyond
381 * last_accounted_offset.
383 if (last_accounted_offset < t) {
384 add += t - last_accounted_offset;
386 nrg = get_file_region_entry_from_cache(
387 resv, last_accounted_offset, t);
388 record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
389 list_add(&nrg->link, rg->link.prev);
390 coalesce_file_region(resv, nrg);
391 } else if (regions_needed)
392 *regions_needed += 1;
399 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
401 static int allocate_file_region_entries(struct resv_map *resv,
403 __must_hold(&resv->lock)
405 struct list_head allocated_regions;
406 int to_allocate = 0, i = 0;
407 struct file_region *trg = NULL, *rg = NULL;
409 VM_BUG_ON(regions_needed < 0);
411 INIT_LIST_HEAD(&allocated_regions);
414 * Check for sufficient descriptors in the cache to accommodate
415 * the number of in progress add operations plus regions_needed.
417 * This is a while loop because when we drop the lock, some other call
418 * to region_add or region_del may have consumed some region_entries,
419 * so we keep looping here until we finally have enough entries for
420 * (adds_in_progress + regions_needed).
422 while (resv->region_cache_count <
423 (resv->adds_in_progress + regions_needed)) {
424 to_allocate = resv->adds_in_progress + regions_needed -
425 resv->region_cache_count;
427 /* At this point, we should have enough entries in the cache
428 * for all the existings adds_in_progress. We should only be
429 * needing to allocate for regions_needed.
431 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
433 spin_unlock(&resv->lock);
434 for (i = 0; i < to_allocate; i++) {
435 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
438 list_add(&trg->link, &allocated_regions);
441 spin_lock(&resv->lock);
443 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
445 list_add(&rg->link, &resv->region_cache);
446 resv->region_cache_count++;
453 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
461 * Add the huge page range represented by [f, t) to the reserve
462 * map. Regions will be taken from the cache to fill in this range.
463 * Sufficient regions should exist in the cache due to the previous
464 * call to region_chg with the same range, but in some cases the cache will not
465 * have sufficient entries due to races with other code doing region_add or
466 * region_del. The extra needed entries will be allocated.
468 * regions_needed is the out value provided by a previous call to region_chg.
470 * Return the number of new huge pages added to the map. This number is greater
471 * than or equal to zero. If file_region entries needed to be allocated for
472 * this operation and we were not able to allocate, it ruturns -ENOMEM.
473 * region_add of regions of length 1 never allocate file_regions and cannot
474 * fail; region_chg will always allocate at least 1 entry and a region_add for
475 * 1 page will only require at most 1 entry.
477 static long region_add(struct resv_map *resv, long f, long t,
478 long in_regions_needed, struct hstate *h,
479 struct hugetlb_cgroup *h_cg)
481 long add = 0, actual_regions_needed = 0;
483 spin_lock(&resv->lock);
486 /* Count how many regions are actually needed to execute this add. */
487 add_reservation_in_range(resv, f, t, NULL, NULL, &actual_regions_needed,
491 * Check for sufficient descriptors in the cache to accommodate
492 * this add operation. Note that actual_regions_needed may be greater
493 * than in_regions_needed, as the resv_map may have been modified since
494 * the region_chg call. In this case, we need to make sure that we
495 * allocate extra entries, such that we have enough for all the
496 * existing adds_in_progress, plus the excess needed for this
499 if (actual_regions_needed > in_regions_needed &&
500 resv->region_cache_count <
501 resv->adds_in_progress +
502 (actual_regions_needed - in_regions_needed)) {
503 /* region_add operation of range 1 should never need to
504 * allocate file_region entries.
506 VM_BUG_ON(t - f <= 1);
508 if (allocate_file_region_entries(
509 resv, actual_regions_needed - in_regions_needed)) {
516 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL, false);
518 resv->adds_in_progress -= in_regions_needed;
520 spin_unlock(&resv->lock);
526 * Examine the existing reserve map and determine how many
527 * huge pages in the specified range [f, t) are NOT currently
528 * represented. This routine is called before a subsequent
529 * call to region_add that will actually modify the reserve
530 * map to add the specified range [f, t). region_chg does
531 * not change the number of huge pages represented by the
532 * map. A number of new file_region structures is added to the cache as a
533 * placeholder, for the subsequent region_add call to use. At least 1
534 * file_region structure is added.
536 * out_regions_needed is the number of regions added to the
537 * resv->adds_in_progress. This value needs to be provided to a follow up call
538 * to region_add or region_abort for proper accounting.
540 * Returns the number of huge pages that need to be added to the existing
541 * reservation map for the range [f, t). This number is greater or equal to
542 * zero. -ENOMEM is returned if a new file_region structure or cache entry
543 * is needed and can not be allocated.
545 static long region_chg(struct resv_map *resv, long f, long t,
546 long *out_regions_needed)
550 spin_lock(&resv->lock);
552 /* Count how many hugepages in this range are NOT respresented. */
553 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
554 out_regions_needed, true);
556 if (*out_regions_needed == 0)
557 *out_regions_needed = 1;
559 if (allocate_file_region_entries(resv, *out_regions_needed))
562 resv->adds_in_progress += *out_regions_needed;
564 spin_unlock(&resv->lock);
569 * Abort the in progress add operation. The adds_in_progress field
570 * of the resv_map keeps track of the operations in progress between
571 * calls to region_chg and region_add. Operations are sometimes
572 * aborted after the call to region_chg. In such cases, region_abort
573 * is called to decrement the adds_in_progress counter. regions_needed
574 * is the value returned by the region_chg call, it is used to decrement
575 * the adds_in_progress counter.
577 * NOTE: The range arguments [f, t) are not needed or used in this
578 * routine. They are kept to make reading the calling code easier as
579 * arguments will match the associated region_chg call.
581 static void region_abort(struct resv_map *resv, long f, long t,
584 spin_lock(&resv->lock);
585 VM_BUG_ON(!resv->region_cache_count);
586 resv->adds_in_progress -= regions_needed;
587 spin_unlock(&resv->lock);
591 * Delete the specified range [f, t) from the reserve map. If the
592 * t parameter is LONG_MAX, this indicates that ALL regions after f
593 * should be deleted. Locate the regions which intersect [f, t)
594 * and either trim, delete or split the existing regions.
596 * Returns the number of huge pages deleted from the reserve map.
597 * In the normal case, the return value is zero or more. In the
598 * case where a region must be split, a new region descriptor must
599 * be allocated. If the allocation fails, -ENOMEM will be returned.
600 * NOTE: If the parameter t == LONG_MAX, then we will never split
601 * a region and possibly return -ENOMEM. Callers specifying
602 * t == LONG_MAX do not need to check for -ENOMEM error.
604 static long region_del(struct resv_map *resv, long f, long t)
606 struct list_head *head = &resv->regions;
607 struct file_region *rg, *trg;
608 struct file_region *nrg = NULL;
612 spin_lock(&resv->lock);
613 list_for_each_entry_safe(rg, trg, head, link) {
615 * Skip regions before the range to be deleted. file_region
616 * ranges are normally of the form [from, to). However, there
617 * may be a "placeholder" entry in the map which is of the form
618 * (from, to) with from == to. Check for placeholder entries
619 * at the beginning of the range to be deleted.
621 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
627 if (f > rg->from && t < rg->to) { /* Must split region */
629 * Check for an entry in the cache before dropping
630 * lock and attempting allocation.
633 resv->region_cache_count > resv->adds_in_progress) {
634 nrg = list_first_entry(&resv->region_cache,
637 list_del(&nrg->link);
638 resv->region_cache_count--;
642 spin_unlock(&resv->lock);
643 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
651 /* New entry for end of split region */
655 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
657 INIT_LIST_HEAD(&nrg->link);
659 /* Original entry is trimmed */
662 hugetlb_cgroup_uncharge_file_region(
663 resv, rg, nrg->to - nrg->from);
665 list_add(&nrg->link, &rg->link);
670 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
671 del += rg->to - rg->from;
672 hugetlb_cgroup_uncharge_file_region(resv, rg,
679 if (f <= rg->from) { /* Trim beginning of region */
683 hugetlb_cgroup_uncharge_file_region(resv, rg,
685 } else { /* Trim end of region */
689 hugetlb_cgroup_uncharge_file_region(resv, rg,
694 spin_unlock(&resv->lock);
700 * A rare out of memory error was encountered which prevented removal of
701 * the reserve map region for a page. The huge page itself was free'ed
702 * and removed from the page cache. This routine will adjust the subpool
703 * usage count, and the global reserve count if needed. By incrementing
704 * these counts, the reserve map entry which could not be deleted will
705 * appear as a "reserved" entry instead of simply dangling with incorrect
708 void hugetlb_fix_reserve_counts(struct inode *inode)
710 struct hugepage_subpool *spool = subpool_inode(inode);
713 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
715 struct hstate *h = hstate_inode(inode);
717 hugetlb_acct_memory(h, 1);
722 * Count and return the number of huge pages in the reserve map
723 * that intersect with the range [f, t).
725 static long region_count(struct resv_map *resv, long f, long t)
727 struct list_head *head = &resv->regions;
728 struct file_region *rg;
731 spin_lock(&resv->lock);
732 /* Locate each segment we overlap with, and count that overlap. */
733 list_for_each_entry(rg, head, link) {
742 seg_from = max(rg->from, f);
743 seg_to = min(rg->to, t);
745 chg += seg_to - seg_from;
747 spin_unlock(&resv->lock);
753 * Convert the address within this vma to the page offset within
754 * the mapping, in pagecache page units; huge pages here.
756 static pgoff_t vma_hugecache_offset(struct hstate *h,
757 struct vm_area_struct *vma, unsigned long address)
759 return ((address - vma->vm_start) >> huge_page_shift(h)) +
760 (vma->vm_pgoff >> huge_page_order(h));
763 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
764 unsigned long address)
766 return vma_hugecache_offset(hstate_vma(vma), vma, address);
768 EXPORT_SYMBOL_GPL(linear_hugepage_index);
771 * Return the size of the pages allocated when backing a VMA. In the majority
772 * cases this will be same size as used by the page table entries.
774 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
776 if (vma->vm_ops && vma->vm_ops->pagesize)
777 return vma->vm_ops->pagesize(vma);
780 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
783 * Return the page size being used by the MMU to back a VMA. In the majority
784 * of cases, the page size used by the kernel matches the MMU size. On
785 * architectures where it differs, an architecture-specific 'strong'
786 * version of this symbol is required.
788 __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
790 return vma_kernel_pagesize(vma);
794 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
795 * bits of the reservation map pointer, which are always clear due to
798 #define HPAGE_RESV_OWNER (1UL << 0)
799 #define HPAGE_RESV_UNMAPPED (1UL << 1)
800 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
803 * These helpers are used to track how many pages are reserved for
804 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
805 * is guaranteed to have their future faults succeed.
807 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
808 * the reserve counters are updated with the hugetlb_lock held. It is safe
809 * to reset the VMA at fork() time as it is not in use yet and there is no
810 * chance of the global counters getting corrupted as a result of the values.
812 * The private mapping reservation is represented in a subtly different
813 * manner to a shared mapping. A shared mapping has a region map associated
814 * with the underlying file, this region map represents the backing file
815 * pages which have ever had a reservation assigned which this persists even
816 * after the page is instantiated. A private mapping has a region map
817 * associated with the original mmap which is attached to all VMAs which
818 * reference it, this region map represents those offsets which have consumed
819 * reservation ie. where pages have been instantiated.
821 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
823 return (unsigned long)vma->vm_private_data;
826 static void set_vma_private_data(struct vm_area_struct *vma,
829 vma->vm_private_data = (void *)value;
833 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
834 struct hugetlb_cgroup *h_cg,
837 #ifdef CONFIG_CGROUP_HUGETLB
839 resv_map->reservation_counter = NULL;
840 resv_map->pages_per_hpage = 0;
841 resv_map->css = NULL;
843 resv_map->reservation_counter =
844 &h_cg->rsvd_hugepage[hstate_index(h)];
845 resv_map->pages_per_hpage = pages_per_huge_page(h);
846 resv_map->css = &h_cg->css;
851 struct resv_map *resv_map_alloc(void)
853 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
854 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
856 if (!resv_map || !rg) {
862 kref_init(&resv_map->refs);
863 spin_lock_init(&resv_map->lock);
864 INIT_LIST_HEAD(&resv_map->regions);
866 resv_map->adds_in_progress = 0;
868 * Initialize these to 0. On shared mappings, 0's here indicate these
869 * fields don't do cgroup accounting. On private mappings, these will be
870 * re-initialized to the proper values, to indicate that hugetlb cgroup
871 * reservations are to be un-charged from here.
873 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
875 INIT_LIST_HEAD(&resv_map->region_cache);
876 list_add(&rg->link, &resv_map->region_cache);
877 resv_map->region_cache_count = 1;
882 void resv_map_release(struct kref *ref)
884 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
885 struct list_head *head = &resv_map->region_cache;
886 struct file_region *rg, *trg;
888 /* Clear out any active regions before we release the map. */
889 region_del(resv_map, 0, LONG_MAX);
891 /* ... and any entries left in the cache */
892 list_for_each_entry_safe(rg, trg, head, link) {
897 VM_BUG_ON(resv_map->adds_in_progress);
902 static inline struct resv_map *inode_resv_map(struct inode *inode)
905 * At inode evict time, i_mapping may not point to the original
906 * address space within the inode. This original address space
907 * contains the pointer to the resv_map. So, always use the
908 * address space embedded within the inode.
909 * The VERY common case is inode->mapping == &inode->i_data but,
910 * this may not be true for device special inodes.
912 return (struct resv_map *)(&inode->i_data)->private_data;
915 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
917 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
918 if (vma->vm_flags & VM_MAYSHARE) {
919 struct address_space *mapping = vma->vm_file->f_mapping;
920 struct inode *inode = mapping->host;
922 return inode_resv_map(inode);
925 return (struct resv_map *)(get_vma_private_data(vma) &
930 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
932 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
933 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
935 set_vma_private_data(vma, (get_vma_private_data(vma) &
936 HPAGE_RESV_MASK) | (unsigned long)map);
939 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
941 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
942 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
944 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
947 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
949 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
951 return (get_vma_private_data(vma) & flag) != 0;
954 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
955 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
957 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
958 if (!(vma->vm_flags & VM_MAYSHARE))
959 vma->vm_private_data = (void *)0;
962 /* Returns true if the VMA has associated reserve pages */
963 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
965 if (vma->vm_flags & VM_NORESERVE) {
967 * This address is already reserved by other process(chg == 0),
968 * so, we should decrement reserved count. Without decrementing,
969 * reserve count remains after releasing inode, because this
970 * allocated page will go into page cache and is regarded as
971 * coming from reserved pool in releasing step. Currently, we
972 * don't have any other solution to deal with this situation
973 * properly, so add work-around here.
975 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
981 /* Shared mappings always use reserves */
982 if (vma->vm_flags & VM_MAYSHARE) {
984 * We know VM_NORESERVE is not set. Therefore, there SHOULD
985 * be a region map for all pages. The only situation where
986 * there is no region map is if a hole was punched via
987 * fallocate. In this case, there really are no reverves to
988 * use. This situation is indicated if chg != 0.
997 * Only the process that called mmap() has reserves for
1000 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1002 * Like the shared case above, a hole punch or truncate
1003 * could have been performed on the private mapping.
1004 * Examine the value of chg to determine if reserves
1005 * actually exist or were previously consumed.
1006 * Very Subtle - The value of chg comes from a previous
1007 * call to vma_needs_reserves(). The reserve map for
1008 * private mappings has different (opposite) semantics
1009 * than that of shared mappings. vma_needs_reserves()
1010 * has already taken this difference in semantics into
1011 * account. Therefore, the meaning of chg is the same
1012 * as in the shared case above. Code could easily be
1013 * combined, but keeping it separate draws attention to
1014 * subtle differences.
1025 static void enqueue_huge_page(struct hstate *h, struct page *page)
1027 int nid = page_to_nid(page);
1028 list_move(&page->lru, &h->hugepage_freelists[nid]);
1029 h->free_huge_pages++;
1030 h->free_huge_pages_node[nid]++;
1033 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1037 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
1038 if (!PageHWPoison(page))
1041 * if 'non-isolated free hugepage' not found on the list,
1042 * the allocation fails.
1044 if (&h->hugepage_freelists[nid] == &page->lru)
1046 list_move(&page->lru, &h->hugepage_activelist);
1047 set_page_refcounted(page);
1048 h->free_huge_pages--;
1049 h->free_huge_pages_node[nid]--;
1053 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1056 unsigned int cpuset_mems_cookie;
1057 struct zonelist *zonelist;
1060 int node = NUMA_NO_NODE;
1062 zonelist = node_zonelist(nid, gfp_mask);
1065 cpuset_mems_cookie = read_mems_allowed_begin();
1066 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1069 if (!cpuset_zone_allowed(zone, gfp_mask))
1072 * no need to ask again on the same node. Pool is node rather than
1075 if (zone_to_nid(zone) == node)
1077 node = zone_to_nid(zone);
1079 page = dequeue_huge_page_node_exact(h, node);
1083 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1089 /* Movability of hugepages depends on migration support. */
1090 static inline gfp_t htlb_alloc_mask(struct hstate *h)
1092 if (hugepage_movable_supported(h))
1093 return GFP_HIGHUSER_MOVABLE;
1095 return GFP_HIGHUSER;
1098 static struct page *dequeue_huge_page_vma(struct hstate *h,
1099 struct vm_area_struct *vma,
1100 unsigned long address, int avoid_reserve,
1104 struct mempolicy *mpol;
1106 nodemask_t *nodemask;
1110 * A child process with MAP_PRIVATE mappings created by their parent
1111 * have no page reserves. This check ensures that reservations are
1112 * not "stolen". The child may still get SIGKILLed
1114 if (!vma_has_reserves(vma, chg) &&
1115 h->free_huge_pages - h->resv_huge_pages == 0)
1118 /* If reserves cannot be used, ensure enough pages are in the pool */
1119 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1122 gfp_mask = htlb_alloc_mask(h);
1123 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1124 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1125 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1126 SetPagePrivate(page);
1127 h->resv_huge_pages--;
1130 mpol_cond_put(mpol);
1138 * common helper functions for hstate_next_node_to_{alloc|free}.
1139 * We may have allocated or freed a huge page based on a different
1140 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1141 * be outside of *nodes_allowed. Ensure that we use an allowed
1142 * node for alloc or free.
1144 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1146 nid = next_node_in(nid, *nodes_allowed);
1147 VM_BUG_ON(nid >= MAX_NUMNODES);
1152 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1154 if (!node_isset(nid, *nodes_allowed))
1155 nid = next_node_allowed(nid, nodes_allowed);
1160 * returns the previously saved node ["this node"] from which to
1161 * allocate a persistent huge page for the pool and advance the
1162 * next node from which to allocate, handling wrap at end of node
1165 static int hstate_next_node_to_alloc(struct hstate *h,
1166 nodemask_t *nodes_allowed)
1170 VM_BUG_ON(!nodes_allowed);
1172 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1173 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1179 * helper for free_pool_huge_page() - return the previously saved
1180 * node ["this node"] from which to free a huge page. Advance the
1181 * next node id whether or not we find a free huge page to free so
1182 * that the next attempt to free addresses the next node.
1184 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1188 VM_BUG_ON(!nodes_allowed);
1190 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1191 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1196 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1197 for (nr_nodes = nodes_weight(*mask); \
1199 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1202 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1203 for (nr_nodes = nodes_weight(*mask); \
1205 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1208 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1209 static void destroy_compound_gigantic_page(struct page *page,
1213 int nr_pages = 1 << order;
1214 struct page *p = page + 1;
1216 atomic_set(compound_mapcount_ptr(page), 0);
1217 if (hpage_pincount_available(page))
1218 atomic_set(compound_pincount_ptr(page), 0);
1220 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1221 clear_compound_head(p);
1222 set_page_refcounted(p);
1225 set_compound_order(page, 0);
1226 __ClearPageHead(page);
1229 static void free_gigantic_page(struct page *page, unsigned int order)
1231 free_contig_range(page_to_pfn(page), 1 << order);
1234 #ifdef CONFIG_CONTIG_ALLOC
1235 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1236 int nid, nodemask_t *nodemask)
1238 unsigned long nr_pages = 1UL << huge_page_order(h);
1240 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1243 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1244 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1245 #else /* !CONFIG_CONTIG_ALLOC */
1246 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1247 int nid, nodemask_t *nodemask)
1251 #endif /* CONFIG_CONTIG_ALLOC */
1253 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1254 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1255 int nid, nodemask_t *nodemask)
1259 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1260 static inline void destroy_compound_gigantic_page(struct page *page,
1261 unsigned int order) { }
1264 static void update_and_free_page(struct hstate *h, struct page *page)
1268 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1272 h->nr_huge_pages_node[page_to_nid(page)]--;
1273 for (i = 0; i < pages_per_huge_page(h); i++) {
1274 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1275 1 << PG_referenced | 1 << PG_dirty |
1276 1 << PG_active | 1 << PG_private |
1279 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1280 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1281 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1282 set_page_refcounted(page);
1283 if (hstate_is_gigantic(h)) {
1284 destroy_compound_gigantic_page(page, huge_page_order(h));
1285 free_gigantic_page(page, huge_page_order(h));
1287 __free_pages(page, huge_page_order(h));
1291 struct hstate *size_to_hstate(unsigned long size)
1295 for_each_hstate(h) {
1296 if (huge_page_size(h) == size)
1303 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1304 * to hstate->hugepage_activelist.)
1306 * This function can be called for tail pages, but never returns true for them.
1308 bool page_huge_active(struct page *page)
1310 VM_BUG_ON_PAGE(!PageHuge(page), page);
1311 return PageHead(page) && PagePrivate(&page[1]);
1314 /* never called for tail page */
1315 static void set_page_huge_active(struct page *page)
1317 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1318 SetPagePrivate(&page[1]);
1321 static void clear_page_huge_active(struct page *page)
1323 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1324 ClearPagePrivate(&page[1]);
1328 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1331 static inline bool PageHugeTemporary(struct page *page)
1333 if (!PageHuge(page))
1336 return (unsigned long)page[2].mapping == -1U;
1339 static inline void SetPageHugeTemporary(struct page *page)
1341 page[2].mapping = (void *)-1U;
1344 static inline void ClearPageHugeTemporary(struct page *page)
1346 page[2].mapping = NULL;
1349 static void __free_huge_page(struct page *page)
1352 * Can't pass hstate in here because it is called from the
1353 * compound page destructor.
1355 struct hstate *h = page_hstate(page);
1356 int nid = page_to_nid(page);
1357 struct hugepage_subpool *spool =
1358 (struct hugepage_subpool *)page_private(page);
1359 bool restore_reserve;
1361 VM_BUG_ON_PAGE(page_count(page), page);
1362 VM_BUG_ON_PAGE(page_mapcount(page), page);
1364 set_page_private(page, 0);
1365 page->mapping = NULL;
1366 restore_reserve = PagePrivate(page);
1367 ClearPagePrivate(page);
1370 * If PagePrivate() was set on page, page allocation consumed a
1371 * reservation. If the page was associated with a subpool, there
1372 * would have been a page reserved in the subpool before allocation
1373 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1374 * reservtion, do not call hugepage_subpool_put_pages() as this will
1375 * remove the reserved page from the subpool.
1377 if (!restore_reserve) {
1379 * A return code of zero implies that the subpool will be
1380 * under its minimum size if the reservation is not restored
1381 * after page is free. Therefore, force restore_reserve
1384 if (hugepage_subpool_put_pages(spool, 1) == 0)
1385 restore_reserve = true;
1388 spin_lock(&hugetlb_lock);
1389 clear_page_huge_active(page);
1390 hugetlb_cgroup_uncharge_page(hstate_index(h),
1391 pages_per_huge_page(h), page);
1392 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1393 pages_per_huge_page(h), page);
1394 if (restore_reserve)
1395 h->resv_huge_pages++;
1397 if (PageHugeTemporary(page)) {
1398 list_del(&page->lru);
1399 ClearPageHugeTemporary(page);
1400 update_and_free_page(h, page);
1401 } else if (h->surplus_huge_pages_node[nid]) {
1402 /* remove the page from active list */
1403 list_del(&page->lru);
1404 update_and_free_page(h, page);
1405 h->surplus_huge_pages--;
1406 h->surplus_huge_pages_node[nid]--;
1408 arch_clear_hugepage_flags(page);
1409 enqueue_huge_page(h, page);
1411 spin_unlock(&hugetlb_lock);
1415 * As free_huge_page() can be called from a non-task context, we have
1416 * to defer the actual freeing in a workqueue to prevent potential
1417 * hugetlb_lock deadlock.
1419 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1420 * be freed and frees them one-by-one. As the page->mapping pointer is
1421 * going to be cleared in __free_huge_page() anyway, it is reused as the
1422 * llist_node structure of a lockless linked list of huge pages to be freed.
1424 static LLIST_HEAD(hpage_freelist);
1426 static void free_hpage_workfn(struct work_struct *work)
1428 struct llist_node *node;
1431 node = llist_del_all(&hpage_freelist);
1434 page = container_of((struct address_space **)node,
1435 struct page, mapping);
1437 __free_huge_page(page);
1440 static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1442 void free_huge_page(struct page *page)
1445 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1449 * Only call schedule_work() if hpage_freelist is previously
1450 * empty. Otherwise, schedule_work() had been called but the
1451 * workfn hasn't retrieved the list yet.
1453 if (llist_add((struct llist_node *)&page->mapping,
1455 schedule_work(&free_hpage_work);
1459 __free_huge_page(page);
1462 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1464 INIT_LIST_HEAD(&page->lru);
1465 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1466 spin_lock(&hugetlb_lock);
1467 set_hugetlb_cgroup(page, NULL);
1468 set_hugetlb_cgroup_rsvd(page, NULL);
1470 h->nr_huge_pages_node[nid]++;
1471 spin_unlock(&hugetlb_lock);
1474 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1477 int nr_pages = 1 << order;
1478 struct page *p = page + 1;
1480 /* we rely on prep_new_huge_page to set the destructor */
1481 set_compound_order(page, order);
1482 __ClearPageReserved(page);
1483 __SetPageHead(page);
1484 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1486 * For gigantic hugepages allocated through bootmem at
1487 * boot, it's safer to be consistent with the not-gigantic
1488 * hugepages and clear the PG_reserved bit from all tail pages
1489 * too. Otherwse drivers using get_user_pages() to access tail
1490 * pages may get the reference counting wrong if they see
1491 * PG_reserved set on a tail page (despite the head page not
1492 * having PG_reserved set). Enforcing this consistency between
1493 * head and tail pages allows drivers to optimize away a check
1494 * on the head page when they need know if put_page() is needed
1495 * after get_user_pages().
1497 __ClearPageReserved(p);
1498 set_page_count(p, 0);
1499 set_compound_head(p, page);
1501 atomic_set(compound_mapcount_ptr(page), -1);
1503 if (hpage_pincount_available(page))
1504 atomic_set(compound_pincount_ptr(page), 0);
1508 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1509 * transparent huge pages. See the PageTransHuge() documentation for more
1512 int PageHuge(struct page *page)
1514 if (!PageCompound(page))
1517 page = compound_head(page);
1518 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1520 EXPORT_SYMBOL_GPL(PageHuge);
1523 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1524 * normal or transparent huge pages.
1526 int PageHeadHuge(struct page *page_head)
1528 if (!PageHead(page_head))
1531 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1535 * Find address_space associated with hugetlbfs page.
1536 * Upon entry page is locked and page 'was' mapped although mapped state
1537 * could change. If necessary, use anon_vma to find vma and associated
1538 * address space. The returned mapping may be stale, but it can not be
1539 * invalid as page lock (which is held) is required to destroy mapping.
1541 static struct address_space *_get_hugetlb_page_mapping(struct page *hpage)
1543 struct anon_vma *anon_vma;
1544 pgoff_t pgoff_start, pgoff_end;
1545 struct anon_vma_chain *avc;
1546 struct address_space *mapping = page_mapping(hpage);
1548 /* Simple file based mapping */
1553 * Even anonymous hugetlbfs mappings are associated with an
1554 * underlying hugetlbfs file (see hugetlb_file_setup in mmap
1555 * code). Find a vma associated with the anonymous vma, and
1556 * use the file pointer to get address_space.
1558 anon_vma = page_lock_anon_vma_read(hpage);
1560 return mapping; /* NULL */
1562 /* Use first found vma */
1563 pgoff_start = page_to_pgoff(hpage);
1564 pgoff_end = pgoff_start + hpage_nr_pages(hpage) - 1;
1565 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root,
1566 pgoff_start, pgoff_end) {
1567 struct vm_area_struct *vma = avc->vma;
1569 mapping = vma->vm_file->f_mapping;
1573 anon_vma_unlock_read(anon_vma);
1578 * Find and lock address space (mapping) in write mode.
1580 * Upon entry, the page is locked which allows us to find the mapping
1581 * even in the case of an anon page. However, locking order dictates
1582 * the i_mmap_rwsem be acquired BEFORE the page lock. This is hugetlbfs
1583 * specific. So, we first try to lock the sema while still holding the
1584 * page lock. If this works, great! If not, then we need to drop the
1585 * page lock and then acquire i_mmap_rwsem and reacquire page lock. Of
1586 * course, need to revalidate state along the way.
1588 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1590 struct address_space *mapping, *mapping2;
1592 mapping = _get_hugetlb_page_mapping(hpage);
1598 * If no contention, take lock and return
1600 if (i_mmap_trylock_write(mapping))
1604 * Must drop page lock and wait on mapping sema.
1605 * Note: Once page lock is dropped, mapping could become invalid.
1606 * As a hack, increase map count until we lock page again.
1608 atomic_inc(&hpage->_mapcount);
1610 i_mmap_lock_write(mapping);
1612 atomic_add_negative(-1, &hpage->_mapcount);
1614 /* verify page is still mapped */
1615 if (!page_mapped(hpage)) {
1616 i_mmap_unlock_write(mapping);
1621 * Get address space again and verify it is the same one
1622 * we locked. If not, drop lock and retry.
1624 mapping2 = _get_hugetlb_page_mapping(hpage);
1625 if (mapping2 != mapping) {
1626 i_mmap_unlock_write(mapping);
1634 pgoff_t __basepage_index(struct page *page)
1636 struct page *page_head = compound_head(page);
1637 pgoff_t index = page_index(page_head);
1638 unsigned long compound_idx;
1640 if (!PageHuge(page_head))
1641 return page_index(page);
1643 if (compound_order(page_head) >= MAX_ORDER)
1644 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1646 compound_idx = page - page_head;
1648 return (index << compound_order(page_head)) + compound_idx;
1651 static struct page *alloc_buddy_huge_page(struct hstate *h,
1652 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1653 nodemask_t *node_alloc_noretry)
1655 int order = huge_page_order(h);
1657 bool alloc_try_hard = true;
1660 * By default we always try hard to allocate the page with
1661 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1662 * a loop (to adjust global huge page counts) and previous allocation
1663 * failed, do not continue to try hard on the same node. Use the
1664 * node_alloc_noretry bitmap to manage this state information.
1666 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1667 alloc_try_hard = false;
1668 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1670 gfp_mask |= __GFP_RETRY_MAYFAIL;
1671 if (nid == NUMA_NO_NODE)
1672 nid = numa_mem_id();
1673 page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
1675 __count_vm_event(HTLB_BUDDY_PGALLOC);
1677 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1680 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1681 * indicates an overall state change. Clear bit so that we resume
1682 * normal 'try hard' allocations.
1684 if (node_alloc_noretry && page && !alloc_try_hard)
1685 node_clear(nid, *node_alloc_noretry);
1688 * If we tried hard to get a page but failed, set bit so that
1689 * subsequent attempts will not try as hard until there is an
1690 * overall state change.
1692 if (node_alloc_noretry && !page && alloc_try_hard)
1693 node_set(nid, *node_alloc_noretry);
1699 * Common helper to allocate a fresh hugetlb page. All specific allocators
1700 * should use this function to get new hugetlb pages
1702 static struct page *alloc_fresh_huge_page(struct hstate *h,
1703 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1704 nodemask_t *node_alloc_noretry)
1708 if (hstate_is_gigantic(h))
1709 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1711 page = alloc_buddy_huge_page(h, gfp_mask,
1712 nid, nmask, node_alloc_noretry);
1716 if (hstate_is_gigantic(h))
1717 prep_compound_gigantic_page(page, huge_page_order(h));
1718 prep_new_huge_page(h, page, page_to_nid(page));
1724 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1727 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1728 nodemask_t *node_alloc_noretry)
1732 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1734 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1735 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1736 node_alloc_noretry);
1744 put_page(page); /* free it into the hugepage allocator */
1750 * Free huge page from pool from next node to free.
1751 * Attempt to keep persistent huge pages more or less
1752 * balanced over allowed nodes.
1753 * Called with hugetlb_lock locked.
1755 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1761 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1763 * If we're returning unused surplus pages, only examine
1764 * nodes with surplus pages.
1766 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1767 !list_empty(&h->hugepage_freelists[node])) {
1769 list_entry(h->hugepage_freelists[node].next,
1771 list_del(&page->lru);
1772 h->free_huge_pages--;
1773 h->free_huge_pages_node[node]--;
1775 h->surplus_huge_pages--;
1776 h->surplus_huge_pages_node[node]--;
1778 update_and_free_page(h, page);
1788 * Dissolve a given free hugepage into free buddy pages. This function does
1789 * nothing for in-use hugepages and non-hugepages.
1790 * This function returns values like below:
1792 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1793 * (allocated or reserved.)
1794 * 0: successfully dissolved free hugepages or the page is not a
1795 * hugepage (considered as already dissolved)
1797 int dissolve_free_huge_page(struct page *page)
1801 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1802 if (!PageHuge(page))
1805 spin_lock(&hugetlb_lock);
1806 if (!PageHuge(page)) {
1811 if (!page_count(page)) {
1812 struct page *head = compound_head(page);
1813 struct hstate *h = page_hstate(head);
1814 int nid = page_to_nid(head);
1815 if (h->free_huge_pages - h->resv_huge_pages == 0)
1818 * Move PageHWPoison flag from head page to the raw error page,
1819 * which makes any subpages rather than the error page reusable.
1821 if (PageHWPoison(head) && page != head) {
1822 SetPageHWPoison(page);
1823 ClearPageHWPoison(head);
1825 list_del(&head->lru);
1826 h->free_huge_pages--;
1827 h->free_huge_pages_node[nid]--;
1828 h->max_huge_pages--;
1829 update_and_free_page(h, head);
1833 spin_unlock(&hugetlb_lock);
1838 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1839 * make specified memory blocks removable from the system.
1840 * Note that this will dissolve a free gigantic hugepage completely, if any
1841 * part of it lies within the given range.
1842 * Also note that if dissolve_free_huge_page() returns with an error, all
1843 * free hugepages that were dissolved before that error are lost.
1845 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1851 if (!hugepages_supported())
1854 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1855 page = pfn_to_page(pfn);
1856 rc = dissolve_free_huge_page(page);
1865 * Allocates a fresh surplus page from the page allocator.
1867 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1868 int nid, nodemask_t *nmask)
1870 struct page *page = NULL;
1872 if (hstate_is_gigantic(h))
1875 spin_lock(&hugetlb_lock);
1876 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1878 spin_unlock(&hugetlb_lock);
1880 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1884 spin_lock(&hugetlb_lock);
1886 * We could have raced with the pool size change.
1887 * Double check that and simply deallocate the new page
1888 * if we would end up overcommiting the surpluses. Abuse
1889 * temporary page to workaround the nasty free_huge_page
1892 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1893 SetPageHugeTemporary(page);
1894 spin_unlock(&hugetlb_lock);
1898 h->surplus_huge_pages++;
1899 h->surplus_huge_pages_node[page_to_nid(page)]++;
1903 spin_unlock(&hugetlb_lock);
1908 struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1909 int nid, nodemask_t *nmask)
1913 if (hstate_is_gigantic(h))
1916 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1921 * We do not account these pages as surplus because they are only
1922 * temporary and will be released properly on the last reference
1924 SetPageHugeTemporary(page);
1930 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1933 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1934 struct vm_area_struct *vma, unsigned long addr)
1937 struct mempolicy *mpol;
1938 gfp_t gfp_mask = htlb_alloc_mask(h);
1940 nodemask_t *nodemask;
1942 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1943 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1944 mpol_cond_put(mpol);
1949 /* page migration callback function */
1950 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1952 gfp_t gfp_mask = htlb_alloc_mask(h);
1953 struct page *page = NULL;
1955 if (nid != NUMA_NO_NODE)
1956 gfp_mask |= __GFP_THISNODE;
1958 spin_lock(&hugetlb_lock);
1959 if (h->free_huge_pages - h->resv_huge_pages > 0)
1960 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
1961 spin_unlock(&hugetlb_lock);
1964 page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
1969 /* page migration callback function */
1970 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1973 gfp_t gfp_mask = htlb_alloc_mask(h);
1975 spin_lock(&hugetlb_lock);
1976 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1979 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1981 spin_unlock(&hugetlb_lock);
1985 spin_unlock(&hugetlb_lock);
1987 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1990 /* mempolicy aware migration callback */
1991 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
1992 unsigned long address)
1994 struct mempolicy *mpol;
1995 nodemask_t *nodemask;
2000 gfp_mask = htlb_alloc_mask(h);
2001 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
2002 page = alloc_huge_page_nodemask(h, node, nodemask);
2003 mpol_cond_put(mpol);
2009 * Increase the hugetlb pool such that it can accommodate a reservation
2012 static int gather_surplus_pages(struct hstate *h, int delta)
2014 struct list_head surplus_list;
2015 struct page *page, *tmp;
2017 int needed, allocated;
2018 bool alloc_ok = true;
2020 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2022 h->resv_huge_pages += delta;
2027 INIT_LIST_HEAD(&surplus_list);
2031 spin_unlock(&hugetlb_lock);
2032 for (i = 0; i < needed; i++) {
2033 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2034 NUMA_NO_NODE, NULL);
2039 list_add(&page->lru, &surplus_list);
2045 * After retaking hugetlb_lock, we need to recalculate 'needed'
2046 * because either resv_huge_pages or free_huge_pages may have changed.
2048 spin_lock(&hugetlb_lock);
2049 needed = (h->resv_huge_pages + delta) -
2050 (h->free_huge_pages + allocated);
2055 * We were not able to allocate enough pages to
2056 * satisfy the entire reservation so we free what
2057 * we've allocated so far.
2062 * The surplus_list now contains _at_least_ the number of extra pages
2063 * needed to accommodate the reservation. Add the appropriate number
2064 * of pages to the hugetlb pool and free the extras back to the buddy
2065 * allocator. Commit the entire reservation here to prevent another
2066 * process from stealing the pages as they are added to the pool but
2067 * before they are reserved.
2069 needed += allocated;
2070 h->resv_huge_pages += delta;
2073 /* Free the needed pages to the hugetlb pool */
2074 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2078 * This page is now managed by the hugetlb allocator and has
2079 * no users -- drop the buddy allocator's reference.
2081 put_page_testzero(page);
2082 VM_BUG_ON_PAGE(page_count(page), page);
2083 enqueue_huge_page(h, page);
2086 spin_unlock(&hugetlb_lock);
2088 /* Free unnecessary surplus pages to the buddy allocator */
2089 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2091 spin_lock(&hugetlb_lock);
2097 * This routine has two main purposes:
2098 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2099 * in unused_resv_pages. This corresponds to the prior adjustments made
2100 * to the associated reservation map.
2101 * 2) Free any unused surplus pages that may have been allocated to satisfy
2102 * the reservation. As many as unused_resv_pages may be freed.
2104 * Called with hugetlb_lock held. However, the lock could be dropped (and
2105 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2106 * we must make sure nobody else can claim pages we are in the process of
2107 * freeing. Do this by ensuring resv_huge_page always is greater than the
2108 * number of huge pages we plan to free when dropping the lock.
2110 static void return_unused_surplus_pages(struct hstate *h,
2111 unsigned long unused_resv_pages)
2113 unsigned long nr_pages;
2115 /* Cannot return gigantic pages currently */
2116 if (hstate_is_gigantic(h))
2120 * Part (or even all) of the reservation could have been backed
2121 * by pre-allocated pages. Only free surplus pages.
2123 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2126 * We want to release as many surplus pages as possible, spread
2127 * evenly across all nodes with memory. Iterate across these nodes
2128 * until we can no longer free unreserved surplus pages. This occurs
2129 * when the nodes with surplus pages have no free pages.
2130 * free_pool_huge_page() will balance the the freed pages across the
2131 * on-line nodes with memory and will handle the hstate accounting.
2133 * Note that we decrement resv_huge_pages as we free the pages. If
2134 * we drop the lock, resv_huge_pages will still be sufficiently large
2135 * to cover subsequent pages we may free.
2137 while (nr_pages--) {
2138 h->resv_huge_pages--;
2139 unused_resv_pages--;
2140 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2142 cond_resched_lock(&hugetlb_lock);
2146 /* Fully uncommit the reservation */
2147 h->resv_huge_pages -= unused_resv_pages;
2152 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2153 * are used by the huge page allocation routines to manage reservations.
2155 * vma_needs_reservation is called to determine if the huge page at addr
2156 * within the vma has an associated reservation. If a reservation is
2157 * needed, the value 1 is returned. The caller is then responsible for
2158 * managing the global reservation and subpool usage counts. After
2159 * the huge page has been allocated, vma_commit_reservation is called
2160 * to add the page to the reservation map. If the page allocation fails,
2161 * the reservation must be ended instead of committed. vma_end_reservation
2162 * is called in such cases.
2164 * In the normal case, vma_commit_reservation returns the same value
2165 * as the preceding vma_needs_reservation call. The only time this
2166 * is not the case is if a reserve map was changed between calls. It
2167 * is the responsibility of the caller to notice the difference and
2168 * take appropriate action.
2170 * vma_add_reservation is used in error paths where a reservation must
2171 * be restored when a newly allocated huge page must be freed. It is
2172 * to be called after calling vma_needs_reservation to determine if a
2173 * reservation exists.
2175 enum vma_resv_mode {
2181 static long __vma_reservation_common(struct hstate *h,
2182 struct vm_area_struct *vma, unsigned long addr,
2183 enum vma_resv_mode mode)
2185 struct resv_map *resv;
2188 long dummy_out_regions_needed;
2190 resv = vma_resv_map(vma);
2194 idx = vma_hugecache_offset(h, vma, addr);
2196 case VMA_NEEDS_RESV:
2197 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2198 /* We assume that vma_reservation_* routines always operate on
2199 * 1 page, and that adding to resv map a 1 page entry can only
2200 * ever require 1 region.
2202 VM_BUG_ON(dummy_out_regions_needed != 1);
2204 case VMA_COMMIT_RESV:
2205 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2206 /* region_add calls of range 1 should never fail. */
2210 region_abort(resv, idx, idx + 1, 1);
2214 if (vma->vm_flags & VM_MAYSHARE) {
2215 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2216 /* region_add calls of range 1 should never fail. */
2219 region_abort(resv, idx, idx + 1, 1);
2220 ret = region_del(resv, idx, idx + 1);
2227 if (vma->vm_flags & VM_MAYSHARE)
2229 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
2231 * In most cases, reserves always exist for private mappings.
2232 * However, a file associated with mapping could have been
2233 * hole punched or truncated after reserves were consumed.
2234 * As subsequent fault on such a range will not use reserves.
2235 * Subtle - The reserve map for private mappings has the
2236 * opposite meaning than that of shared mappings. If NO
2237 * entry is in the reserve map, it means a reservation exists.
2238 * If an entry exists in the reserve map, it means the
2239 * reservation has already been consumed. As a result, the
2240 * return value of this routine is the opposite of the
2241 * value returned from reserve map manipulation routines above.
2249 return ret < 0 ? ret : 0;
2252 static long vma_needs_reservation(struct hstate *h,
2253 struct vm_area_struct *vma, unsigned long addr)
2255 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2258 static long vma_commit_reservation(struct hstate *h,
2259 struct vm_area_struct *vma, unsigned long addr)
2261 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2264 static void vma_end_reservation(struct hstate *h,
2265 struct vm_area_struct *vma, unsigned long addr)
2267 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2270 static long vma_add_reservation(struct hstate *h,
2271 struct vm_area_struct *vma, unsigned long addr)
2273 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2277 * This routine is called to restore a reservation on error paths. In the
2278 * specific error paths, a huge page was allocated (via alloc_huge_page)
2279 * and is about to be freed. If a reservation for the page existed,
2280 * alloc_huge_page would have consumed the reservation and set PagePrivate
2281 * in the newly allocated page. When the page is freed via free_huge_page,
2282 * the global reservation count will be incremented if PagePrivate is set.
2283 * However, free_huge_page can not adjust the reserve map. Adjust the
2284 * reserve map here to be consistent with global reserve count adjustments
2285 * to be made by free_huge_page.
2287 static void restore_reserve_on_error(struct hstate *h,
2288 struct vm_area_struct *vma, unsigned long address,
2291 if (unlikely(PagePrivate(page))) {
2292 long rc = vma_needs_reservation(h, vma, address);
2294 if (unlikely(rc < 0)) {
2296 * Rare out of memory condition in reserve map
2297 * manipulation. Clear PagePrivate so that
2298 * global reserve count will not be incremented
2299 * by free_huge_page. This will make it appear
2300 * as though the reservation for this page was
2301 * consumed. This may prevent the task from
2302 * faulting in the page at a later time. This
2303 * is better than inconsistent global huge page
2304 * accounting of reserve counts.
2306 ClearPagePrivate(page);
2308 rc = vma_add_reservation(h, vma, address);
2309 if (unlikely(rc < 0))
2311 * See above comment about rare out of
2314 ClearPagePrivate(page);
2316 vma_end_reservation(h, vma, address);
2320 struct page *alloc_huge_page(struct vm_area_struct *vma,
2321 unsigned long addr, int avoid_reserve)
2323 struct hugepage_subpool *spool = subpool_vma(vma);
2324 struct hstate *h = hstate_vma(vma);
2326 long map_chg, map_commit;
2329 struct hugetlb_cgroup *h_cg;
2330 bool deferred_reserve;
2332 idx = hstate_index(h);
2334 * Examine the region/reserve map to determine if the process
2335 * has a reservation for the page to be allocated. A return
2336 * code of zero indicates a reservation exists (no change).
2338 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2340 return ERR_PTR(-ENOMEM);
2343 * Processes that did not create the mapping will have no
2344 * reserves as indicated by the region/reserve map. Check
2345 * that the allocation will not exceed the subpool limit.
2346 * Allocations for MAP_NORESERVE mappings also need to be
2347 * checked against any subpool limit.
2349 if (map_chg || avoid_reserve) {
2350 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2352 vma_end_reservation(h, vma, addr);
2353 return ERR_PTR(-ENOSPC);
2357 * Even though there was no reservation in the region/reserve
2358 * map, there could be reservations associated with the
2359 * subpool that can be used. This would be indicated if the
2360 * return value of hugepage_subpool_get_pages() is zero.
2361 * However, if avoid_reserve is specified we still avoid even
2362 * the subpool reservations.
2368 /* If this allocation is not consuming a reservation, charge it now.
2370 deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
2371 if (deferred_reserve) {
2372 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2373 idx, pages_per_huge_page(h), &h_cg);
2375 goto out_subpool_put;
2378 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2380 goto out_uncharge_cgroup_reservation;
2382 spin_lock(&hugetlb_lock);
2384 * glb_chg is passed to indicate whether or not a page must be taken
2385 * from the global free pool (global change). gbl_chg == 0 indicates
2386 * a reservation exists for the allocation.
2388 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2390 spin_unlock(&hugetlb_lock);
2391 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2393 goto out_uncharge_cgroup;
2394 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2395 SetPagePrivate(page);
2396 h->resv_huge_pages--;
2398 spin_lock(&hugetlb_lock);
2399 list_move(&page->lru, &h->hugepage_activelist);
2402 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2403 /* If allocation is not consuming a reservation, also store the
2404 * hugetlb_cgroup pointer on the page.
2406 if (deferred_reserve) {
2407 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2411 spin_unlock(&hugetlb_lock);
2413 set_page_private(page, (unsigned long)spool);
2415 map_commit = vma_commit_reservation(h, vma, addr);
2416 if (unlikely(map_chg > map_commit)) {
2418 * The page was added to the reservation map between
2419 * vma_needs_reservation and vma_commit_reservation.
2420 * This indicates a race with hugetlb_reserve_pages.
2421 * Adjust for the subpool count incremented above AND
2422 * in hugetlb_reserve_pages for the same page. Also,
2423 * the reservation count added in hugetlb_reserve_pages
2424 * no longer applies.
2428 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2429 hugetlb_acct_memory(h, -rsv_adjust);
2433 out_uncharge_cgroup:
2434 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2435 out_uncharge_cgroup_reservation:
2436 if (deferred_reserve)
2437 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2440 if (map_chg || avoid_reserve)
2441 hugepage_subpool_put_pages(spool, 1);
2442 vma_end_reservation(h, vma, addr);
2443 return ERR_PTR(-ENOSPC);
2446 int alloc_bootmem_huge_page(struct hstate *h)
2447 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2448 int __alloc_bootmem_huge_page(struct hstate *h)
2450 struct huge_bootmem_page *m;
2453 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2456 addr = memblock_alloc_try_nid_raw(
2457 huge_page_size(h), huge_page_size(h),
2458 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2461 * Use the beginning of the huge page to store the
2462 * huge_bootmem_page struct (until gather_bootmem
2463 * puts them into the mem_map).
2472 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2473 /* Put them into a private list first because mem_map is not up yet */
2474 INIT_LIST_HEAD(&m->list);
2475 list_add(&m->list, &huge_boot_pages);
2480 static void __init prep_compound_huge_page(struct page *page,
2483 if (unlikely(order > (MAX_ORDER - 1)))
2484 prep_compound_gigantic_page(page, order);
2486 prep_compound_page(page, order);
2489 /* Put bootmem huge pages into the standard lists after mem_map is up */
2490 static void __init gather_bootmem_prealloc(void)
2492 struct huge_bootmem_page *m;
2494 list_for_each_entry(m, &huge_boot_pages, list) {
2495 struct page *page = virt_to_page(m);
2496 struct hstate *h = m->hstate;
2498 WARN_ON(page_count(page) != 1);
2499 prep_compound_huge_page(page, h->order);
2500 WARN_ON(PageReserved(page));
2501 prep_new_huge_page(h, page, page_to_nid(page));
2502 put_page(page); /* free it into the hugepage allocator */
2505 * If we had gigantic hugepages allocated at boot time, we need
2506 * to restore the 'stolen' pages to totalram_pages in order to
2507 * fix confusing memory reports from free(1) and another
2508 * side-effects, like CommitLimit going negative.
2510 if (hstate_is_gigantic(h))
2511 adjust_managed_page_count(page, 1 << h->order);
2516 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2519 nodemask_t *node_alloc_noretry;
2521 if (!hstate_is_gigantic(h)) {
2523 * Bit mask controlling how hard we retry per-node allocations.
2524 * Ignore errors as lower level routines can deal with
2525 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2526 * time, we are likely in bigger trouble.
2528 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2531 /* allocations done at boot time */
2532 node_alloc_noretry = NULL;
2535 /* bit mask controlling how hard we retry per-node allocations */
2536 if (node_alloc_noretry)
2537 nodes_clear(*node_alloc_noretry);
2539 for (i = 0; i < h->max_huge_pages; ++i) {
2540 if (hstate_is_gigantic(h)) {
2541 if (!alloc_bootmem_huge_page(h))
2543 } else if (!alloc_pool_huge_page(h,
2544 &node_states[N_MEMORY],
2545 node_alloc_noretry))
2549 if (i < h->max_huge_pages) {
2552 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2553 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2554 h->max_huge_pages, buf, i);
2555 h->max_huge_pages = i;
2558 kfree(node_alloc_noretry);
2561 static void __init hugetlb_init_hstates(void)
2565 for_each_hstate(h) {
2566 if (minimum_order > huge_page_order(h))
2567 minimum_order = huge_page_order(h);
2569 /* oversize hugepages were init'ed in early boot */
2570 if (!hstate_is_gigantic(h))
2571 hugetlb_hstate_alloc_pages(h);
2573 VM_BUG_ON(minimum_order == UINT_MAX);
2576 static void __init report_hugepages(void)
2580 for_each_hstate(h) {
2583 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2584 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2585 buf, h->free_huge_pages);
2589 #ifdef CONFIG_HIGHMEM
2590 static void try_to_free_low(struct hstate *h, unsigned long count,
2591 nodemask_t *nodes_allowed)
2595 if (hstate_is_gigantic(h))
2598 for_each_node_mask(i, *nodes_allowed) {
2599 struct page *page, *next;
2600 struct list_head *freel = &h->hugepage_freelists[i];
2601 list_for_each_entry_safe(page, next, freel, lru) {
2602 if (count >= h->nr_huge_pages)
2604 if (PageHighMem(page))
2606 list_del(&page->lru);
2607 update_and_free_page(h, page);
2608 h->free_huge_pages--;
2609 h->free_huge_pages_node[page_to_nid(page)]--;
2614 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2615 nodemask_t *nodes_allowed)
2621 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2622 * balanced by operating on them in a round-robin fashion.
2623 * Returns 1 if an adjustment was made.
2625 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2630 VM_BUG_ON(delta != -1 && delta != 1);
2633 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2634 if (h->surplus_huge_pages_node[node])
2638 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2639 if (h->surplus_huge_pages_node[node] <
2640 h->nr_huge_pages_node[node])
2647 h->surplus_huge_pages += delta;
2648 h->surplus_huge_pages_node[node] += delta;
2652 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2653 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2654 nodemask_t *nodes_allowed)
2656 unsigned long min_count, ret;
2657 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2660 * Bit mask controlling how hard we retry per-node allocations.
2661 * If we can not allocate the bit mask, do not attempt to allocate
2662 * the requested huge pages.
2664 if (node_alloc_noretry)
2665 nodes_clear(*node_alloc_noretry);
2669 spin_lock(&hugetlb_lock);
2672 * Check for a node specific request.
2673 * Changing node specific huge page count may require a corresponding
2674 * change to the global count. In any case, the passed node mask
2675 * (nodes_allowed) will restrict alloc/free to the specified node.
2677 if (nid != NUMA_NO_NODE) {
2678 unsigned long old_count = count;
2680 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2682 * User may have specified a large count value which caused the
2683 * above calculation to overflow. In this case, they wanted
2684 * to allocate as many huge pages as possible. Set count to
2685 * largest possible value to align with their intention.
2687 if (count < old_count)
2692 * Gigantic pages runtime allocation depend on the capability for large
2693 * page range allocation.
2694 * If the system does not provide this feature, return an error when
2695 * the user tries to allocate gigantic pages but let the user free the
2696 * boottime allocated gigantic pages.
2698 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2699 if (count > persistent_huge_pages(h)) {
2700 spin_unlock(&hugetlb_lock);
2701 NODEMASK_FREE(node_alloc_noretry);
2704 /* Fall through to decrease pool */
2708 * Increase the pool size
2709 * First take pages out of surplus state. Then make up the
2710 * remaining difference by allocating fresh huge pages.
2712 * We might race with alloc_surplus_huge_page() here and be unable
2713 * to convert a surplus huge page to a normal huge page. That is
2714 * not critical, though, it just means the overall size of the
2715 * pool might be one hugepage larger than it needs to be, but
2716 * within all the constraints specified by the sysctls.
2718 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2719 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2723 while (count > persistent_huge_pages(h)) {
2725 * If this allocation races such that we no longer need the
2726 * page, free_huge_page will handle it by freeing the page
2727 * and reducing the surplus.
2729 spin_unlock(&hugetlb_lock);
2731 /* yield cpu to avoid soft lockup */
2734 ret = alloc_pool_huge_page(h, nodes_allowed,
2735 node_alloc_noretry);
2736 spin_lock(&hugetlb_lock);
2740 /* Bail for signals. Probably ctrl-c from user */
2741 if (signal_pending(current))
2746 * Decrease the pool size
2747 * First return free pages to the buddy allocator (being careful
2748 * to keep enough around to satisfy reservations). Then place
2749 * pages into surplus state as needed so the pool will shrink
2750 * to the desired size as pages become free.
2752 * By placing pages into the surplus state independent of the
2753 * overcommit value, we are allowing the surplus pool size to
2754 * exceed overcommit. There are few sane options here. Since
2755 * alloc_surplus_huge_page() is checking the global counter,
2756 * though, we'll note that we're not allowed to exceed surplus
2757 * and won't grow the pool anywhere else. Not until one of the
2758 * sysctls are changed, or the surplus pages go out of use.
2760 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2761 min_count = max(count, min_count);
2762 try_to_free_low(h, min_count, nodes_allowed);
2763 while (min_count < persistent_huge_pages(h)) {
2764 if (!free_pool_huge_page(h, nodes_allowed, 0))
2766 cond_resched_lock(&hugetlb_lock);
2768 while (count < persistent_huge_pages(h)) {
2769 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2773 h->max_huge_pages = persistent_huge_pages(h);
2774 spin_unlock(&hugetlb_lock);
2776 NODEMASK_FREE(node_alloc_noretry);
2781 #define HSTATE_ATTR_RO(_name) \
2782 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2784 #define HSTATE_ATTR(_name) \
2785 static struct kobj_attribute _name##_attr = \
2786 __ATTR(_name, 0644, _name##_show, _name##_store)
2788 static struct kobject *hugepages_kobj;
2789 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2791 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2793 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2797 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2798 if (hstate_kobjs[i] == kobj) {
2800 *nidp = NUMA_NO_NODE;
2804 return kobj_to_node_hstate(kobj, nidp);
2807 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2808 struct kobj_attribute *attr, char *buf)
2811 unsigned long nr_huge_pages;
2814 h = kobj_to_hstate(kobj, &nid);
2815 if (nid == NUMA_NO_NODE)
2816 nr_huge_pages = h->nr_huge_pages;
2818 nr_huge_pages = h->nr_huge_pages_node[nid];
2820 return sprintf(buf, "%lu\n", nr_huge_pages);
2823 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2824 struct hstate *h, int nid,
2825 unsigned long count, size_t len)
2828 nodemask_t nodes_allowed, *n_mask;
2830 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2833 if (nid == NUMA_NO_NODE) {
2835 * global hstate attribute
2837 if (!(obey_mempolicy &&
2838 init_nodemask_of_mempolicy(&nodes_allowed)))
2839 n_mask = &node_states[N_MEMORY];
2841 n_mask = &nodes_allowed;
2844 * Node specific request. count adjustment happens in
2845 * set_max_huge_pages() after acquiring hugetlb_lock.
2847 init_nodemask_of_node(&nodes_allowed, nid);
2848 n_mask = &nodes_allowed;
2851 err = set_max_huge_pages(h, count, nid, n_mask);
2853 return err ? err : len;
2856 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2857 struct kobject *kobj, const char *buf,
2861 unsigned long count;
2865 err = kstrtoul(buf, 10, &count);
2869 h = kobj_to_hstate(kobj, &nid);
2870 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2873 static ssize_t nr_hugepages_show(struct kobject *kobj,
2874 struct kobj_attribute *attr, char *buf)
2876 return nr_hugepages_show_common(kobj, attr, buf);
2879 static ssize_t nr_hugepages_store(struct kobject *kobj,
2880 struct kobj_attribute *attr, const char *buf, size_t len)
2882 return nr_hugepages_store_common(false, kobj, buf, len);
2884 HSTATE_ATTR(nr_hugepages);
2889 * hstate attribute for optionally mempolicy-based constraint on persistent
2890 * huge page alloc/free.
2892 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2893 struct kobj_attribute *attr, char *buf)
2895 return nr_hugepages_show_common(kobj, attr, buf);
2898 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2899 struct kobj_attribute *attr, const char *buf, size_t len)
2901 return nr_hugepages_store_common(true, kobj, buf, len);
2903 HSTATE_ATTR(nr_hugepages_mempolicy);
2907 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2908 struct kobj_attribute *attr, char *buf)
2910 struct hstate *h = kobj_to_hstate(kobj, NULL);
2911 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2914 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2915 struct kobj_attribute *attr, const char *buf, size_t count)
2918 unsigned long input;
2919 struct hstate *h = kobj_to_hstate(kobj, NULL);
2921 if (hstate_is_gigantic(h))
2924 err = kstrtoul(buf, 10, &input);
2928 spin_lock(&hugetlb_lock);
2929 h->nr_overcommit_huge_pages = input;
2930 spin_unlock(&hugetlb_lock);
2934 HSTATE_ATTR(nr_overcommit_hugepages);
2936 static ssize_t free_hugepages_show(struct kobject *kobj,
2937 struct kobj_attribute *attr, char *buf)
2940 unsigned long free_huge_pages;
2943 h = kobj_to_hstate(kobj, &nid);
2944 if (nid == NUMA_NO_NODE)
2945 free_huge_pages = h->free_huge_pages;
2947 free_huge_pages = h->free_huge_pages_node[nid];
2949 return sprintf(buf, "%lu\n", free_huge_pages);
2951 HSTATE_ATTR_RO(free_hugepages);
2953 static ssize_t resv_hugepages_show(struct kobject *kobj,
2954 struct kobj_attribute *attr, char *buf)
2956 struct hstate *h = kobj_to_hstate(kobj, NULL);
2957 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2959 HSTATE_ATTR_RO(resv_hugepages);
2961 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2962 struct kobj_attribute *attr, char *buf)
2965 unsigned long surplus_huge_pages;
2968 h = kobj_to_hstate(kobj, &nid);
2969 if (nid == NUMA_NO_NODE)
2970 surplus_huge_pages = h->surplus_huge_pages;
2972 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2974 return sprintf(buf, "%lu\n", surplus_huge_pages);
2976 HSTATE_ATTR_RO(surplus_hugepages);
2978 static struct attribute *hstate_attrs[] = {
2979 &nr_hugepages_attr.attr,
2980 &nr_overcommit_hugepages_attr.attr,
2981 &free_hugepages_attr.attr,
2982 &resv_hugepages_attr.attr,
2983 &surplus_hugepages_attr.attr,
2985 &nr_hugepages_mempolicy_attr.attr,
2990 static const struct attribute_group hstate_attr_group = {
2991 .attrs = hstate_attrs,
2994 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2995 struct kobject **hstate_kobjs,
2996 const struct attribute_group *hstate_attr_group)
2999 int hi = hstate_index(h);
3001 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3002 if (!hstate_kobjs[hi])
3005 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3007 kobject_put(hstate_kobjs[hi]);
3012 static void __init hugetlb_sysfs_init(void)
3017 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3018 if (!hugepages_kobj)
3021 for_each_hstate(h) {
3022 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3023 hstate_kobjs, &hstate_attr_group);
3025 pr_err("Hugetlb: Unable to add hstate %s", h->name);
3032 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3033 * with node devices in node_devices[] using a parallel array. The array
3034 * index of a node device or _hstate == node id.
3035 * This is here to avoid any static dependency of the node device driver, in
3036 * the base kernel, on the hugetlb module.
3038 struct node_hstate {
3039 struct kobject *hugepages_kobj;
3040 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3042 static struct node_hstate node_hstates[MAX_NUMNODES];
3045 * A subset of global hstate attributes for node devices
3047 static struct attribute *per_node_hstate_attrs[] = {
3048 &nr_hugepages_attr.attr,
3049 &free_hugepages_attr.attr,
3050 &surplus_hugepages_attr.attr,
3054 static const struct attribute_group per_node_hstate_attr_group = {
3055 .attrs = per_node_hstate_attrs,
3059 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3060 * Returns node id via non-NULL nidp.
3062 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3066 for (nid = 0; nid < nr_node_ids; nid++) {
3067 struct node_hstate *nhs = &node_hstates[nid];
3069 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3070 if (nhs->hstate_kobjs[i] == kobj) {
3082 * Unregister hstate attributes from a single node device.
3083 * No-op if no hstate attributes attached.
3085 static void hugetlb_unregister_node(struct node *node)
3088 struct node_hstate *nhs = &node_hstates[node->dev.id];
3090 if (!nhs->hugepages_kobj)
3091 return; /* no hstate attributes */
3093 for_each_hstate(h) {
3094 int idx = hstate_index(h);
3095 if (nhs->hstate_kobjs[idx]) {
3096 kobject_put(nhs->hstate_kobjs[idx]);
3097 nhs->hstate_kobjs[idx] = NULL;
3101 kobject_put(nhs->hugepages_kobj);
3102 nhs->hugepages_kobj = NULL;
3107 * Register hstate attributes for a single node device.
3108 * No-op if attributes already registered.
3110 static void hugetlb_register_node(struct node *node)
3113 struct node_hstate *nhs = &node_hstates[node->dev.id];
3116 if (nhs->hugepages_kobj)
3117 return; /* already allocated */
3119 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3121 if (!nhs->hugepages_kobj)
3124 for_each_hstate(h) {
3125 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3127 &per_node_hstate_attr_group);
3129 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
3130 h->name, node->dev.id);
3131 hugetlb_unregister_node(node);
3138 * hugetlb init time: register hstate attributes for all registered node
3139 * devices of nodes that have memory. All on-line nodes should have
3140 * registered their associated device by this time.
3142 static void __init hugetlb_register_all_nodes(void)
3146 for_each_node_state(nid, N_MEMORY) {
3147 struct node *node = node_devices[nid];
3148 if (node->dev.id == nid)
3149 hugetlb_register_node(node);
3153 * Let the node device driver know we're here so it can
3154 * [un]register hstate attributes on node hotplug.
3156 register_hugetlbfs_with_node(hugetlb_register_node,
3157 hugetlb_unregister_node);
3159 #else /* !CONFIG_NUMA */
3161 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3169 static void hugetlb_register_all_nodes(void) { }
3173 static int __init hugetlb_init(void)
3177 if (!hugepages_supported())
3180 if (!size_to_hstate(default_hstate_size)) {
3181 if (default_hstate_size != 0) {
3182 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
3183 default_hstate_size, HPAGE_SIZE);
3186 default_hstate_size = HPAGE_SIZE;
3187 if (!size_to_hstate(default_hstate_size))
3188 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3190 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
3191 if (default_hstate_max_huge_pages) {
3192 if (!default_hstate.max_huge_pages)
3193 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3196 hugetlb_init_hstates();
3197 gather_bootmem_prealloc();
3200 hugetlb_sysfs_init();
3201 hugetlb_register_all_nodes();
3202 hugetlb_cgroup_file_init();
3205 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3207 num_fault_mutexes = 1;
3209 hugetlb_fault_mutex_table =
3210 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3212 BUG_ON(!hugetlb_fault_mutex_table);
3214 for (i = 0; i < num_fault_mutexes; i++)
3215 mutex_init(&hugetlb_fault_mutex_table[i]);
3218 subsys_initcall(hugetlb_init);
3220 /* Should be called on processing a hugepagesz=... option */
3221 void __init hugetlb_bad_size(void)
3223 parsed_valid_hugepagesz = false;
3226 void __init hugetlb_add_hstate(unsigned int order)
3231 if (size_to_hstate(PAGE_SIZE << order)) {
3232 pr_warn("hugepagesz= specified twice, ignoring\n");
3235 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3237 h = &hstates[hugetlb_max_hstate++];
3239 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3240 h->nr_huge_pages = 0;
3241 h->free_huge_pages = 0;
3242 for (i = 0; i < MAX_NUMNODES; ++i)
3243 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3244 INIT_LIST_HEAD(&h->hugepage_activelist);
3245 h->next_nid_to_alloc = first_memory_node;
3246 h->next_nid_to_free = first_memory_node;
3247 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3248 huge_page_size(h)/1024);
3253 static int __init hugetlb_nrpages_setup(char *s)
3256 static unsigned long *last_mhp;
3258 if (!parsed_valid_hugepagesz) {
3259 pr_warn("hugepages = %s preceded by "
3260 "an unsupported hugepagesz, ignoring\n", s);
3261 parsed_valid_hugepagesz = true;
3265 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
3266 * so this hugepages= parameter goes to the "default hstate".
3268 else if (!hugetlb_max_hstate)
3269 mhp = &default_hstate_max_huge_pages;
3271 mhp = &parsed_hstate->max_huge_pages;
3273 if (mhp == last_mhp) {
3274 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
3278 if (sscanf(s, "%lu", mhp) <= 0)
3282 * Global state is always initialized later in hugetlb_init.
3283 * But we need to allocate >= MAX_ORDER hstates here early to still
3284 * use the bootmem allocator.
3286 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3287 hugetlb_hstate_alloc_pages(parsed_hstate);
3293 __setup("hugepages=", hugetlb_nrpages_setup);
3295 static int __init hugetlb_default_setup(char *s)
3297 default_hstate_size = memparse(s, &s);
3300 __setup("default_hugepagesz=", hugetlb_default_setup);
3302 static unsigned int cpuset_mems_nr(unsigned int *array)
3305 unsigned int nr = 0;
3307 for_each_node_mask(node, cpuset_current_mems_allowed)
3313 #ifdef CONFIG_SYSCTL
3314 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3315 struct ctl_table *table, int write,
3316 void __user *buffer, size_t *length, loff_t *ppos)
3318 struct hstate *h = &default_hstate;
3319 unsigned long tmp = h->max_huge_pages;
3322 if (!hugepages_supported())
3326 table->maxlen = sizeof(unsigned long);
3327 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
3332 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3333 NUMA_NO_NODE, tmp, *length);
3338 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3339 void __user *buffer, size_t *length, loff_t *ppos)
3342 return hugetlb_sysctl_handler_common(false, table, write,
3343 buffer, length, ppos);
3347 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3348 void __user *buffer, size_t *length, loff_t *ppos)
3350 return hugetlb_sysctl_handler_common(true, table, write,
3351 buffer, length, ppos);
3353 #endif /* CONFIG_NUMA */
3355 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3356 void __user *buffer,
3357 size_t *length, loff_t *ppos)
3359 struct hstate *h = &default_hstate;
3363 if (!hugepages_supported())
3366 tmp = h->nr_overcommit_huge_pages;
3368 if (write && hstate_is_gigantic(h))
3372 table->maxlen = sizeof(unsigned long);
3373 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
3378 spin_lock(&hugetlb_lock);
3379 h->nr_overcommit_huge_pages = tmp;
3380 spin_unlock(&hugetlb_lock);
3386 #endif /* CONFIG_SYSCTL */
3388 void hugetlb_report_meminfo(struct seq_file *m)
3391 unsigned long total = 0;
3393 if (!hugepages_supported())
3396 for_each_hstate(h) {
3397 unsigned long count = h->nr_huge_pages;
3399 total += (PAGE_SIZE << huge_page_order(h)) * count;
3401 if (h == &default_hstate)
3403 "HugePages_Total: %5lu\n"
3404 "HugePages_Free: %5lu\n"
3405 "HugePages_Rsvd: %5lu\n"
3406 "HugePages_Surp: %5lu\n"
3407 "Hugepagesize: %8lu kB\n",
3411 h->surplus_huge_pages,
3412 (PAGE_SIZE << huge_page_order(h)) / 1024);
3415 seq_printf(m, "Hugetlb: %8lu kB\n", total / 1024);
3418 int hugetlb_report_node_meminfo(int nid, char *buf)
3420 struct hstate *h = &default_hstate;
3421 if (!hugepages_supported())
3424 "Node %d HugePages_Total: %5u\n"
3425 "Node %d HugePages_Free: %5u\n"
3426 "Node %d HugePages_Surp: %5u\n",
3427 nid, h->nr_huge_pages_node[nid],
3428 nid, h->free_huge_pages_node[nid],
3429 nid, h->surplus_huge_pages_node[nid]);
3432 void hugetlb_show_meminfo(void)
3437 if (!hugepages_supported())
3440 for_each_node_state(nid, N_MEMORY)
3442 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3444 h->nr_huge_pages_node[nid],
3445 h->free_huge_pages_node[nid],
3446 h->surplus_huge_pages_node[nid],
3447 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3450 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3452 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3453 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3456 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3457 unsigned long hugetlb_total_pages(void)
3460 unsigned long nr_total_pages = 0;
3463 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3464 return nr_total_pages;
3467 static int hugetlb_acct_memory(struct hstate *h, long delta)
3471 spin_lock(&hugetlb_lock);
3473 * When cpuset is configured, it breaks the strict hugetlb page
3474 * reservation as the accounting is done on a global variable. Such
3475 * reservation is completely rubbish in the presence of cpuset because
3476 * the reservation is not checked against page availability for the
3477 * current cpuset. Application can still potentially OOM'ed by kernel
3478 * with lack of free htlb page in cpuset that the task is in.
3479 * Attempt to enforce strict accounting with cpuset is almost
3480 * impossible (or too ugly) because cpuset is too fluid that
3481 * task or memory node can be dynamically moved between cpusets.
3483 * The change of semantics for shared hugetlb mapping with cpuset is
3484 * undesirable. However, in order to preserve some of the semantics,
3485 * we fall back to check against current free page availability as
3486 * a best attempt and hopefully to minimize the impact of changing
3487 * semantics that cpuset has.
3490 if (gather_surplus_pages(h, delta) < 0)
3493 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
3494 return_unused_surplus_pages(h, delta);
3501 return_unused_surplus_pages(h, (unsigned long) -delta);
3504 spin_unlock(&hugetlb_lock);
3508 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3510 struct resv_map *resv = vma_resv_map(vma);
3513 * This new VMA should share its siblings reservation map if present.
3514 * The VMA will only ever have a valid reservation map pointer where
3515 * it is being copied for another still existing VMA. As that VMA
3516 * has a reference to the reservation map it cannot disappear until
3517 * after this open call completes. It is therefore safe to take a
3518 * new reference here without additional locking.
3520 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3521 kref_get(&resv->refs);
3524 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3526 struct hstate *h = hstate_vma(vma);
3527 struct resv_map *resv = vma_resv_map(vma);
3528 struct hugepage_subpool *spool = subpool_vma(vma);
3529 unsigned long reserve, start, end;
3532 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3535 start = vma_hugecache_offset(h, vma, vma->vm_start);
3536 end = vma_hugecache_offset(h, vma, vma->vm_end);
3538 reserve = (end - start) - region_count(resv, start, end);
3539 hugetlb_cgroup_uncharge_counter(resv, start, end);
3542 * Decrement reserve counts. The global reserve count may be
3543 * adjusted if the subpool has a minimum size.
3545 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3546 hugetlb_acct_memory(h, -gbl_reserve);
3549 kref_put(&resv->refs, resv_map_release);
3552 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3554 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3559 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3561 struct hstate *hstate = hstate_vma(vma);
3563 return 1UL << huge_page_shift(hstate);
3567 * We cannot handle pagefaults against hugetlb pages at all. They cause
3568 * handle_mm_fault() to try to instantiate regular-sized pages in the
3569 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3572 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3579 * When a new function is introduced to vm_operations_struct and added
3580 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3581 * This is because under System V memory model, mappings created via
3582 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3583 * their original vm_ops are overwritten with shm_vm_ops.
3585 const struct vm_operations_struct hugetlb_vm_ops = {
3586 .fault = hugetlb_vm_op_fault,
3587 .open = hugetlb_vm_op_open,
3588 .close = hugetlb_vm_op_close,
3589 .split = hugetlb_vm_op_split,
3590 .pagesize = hugetlb_vm_op_pagesize,
3593 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3599 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3600 vma->vm_page_prot)));
3602 entry = huge_pte_wrprotect(mk_huge_pte(page,
3603 vma->vm_page_prot));
3605 entry = pte_mkyoung(entry);
3606 entry = pte_mkhuge(entry);
3607 entry = arch_make_huge_pte(entry, vma, page, writable);
3612 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3613 unsigned long address, pte_t *ptep)
3617 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3618 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3619 update_mmu_cache(vma, address, ptep);
3622 bool is_hugetlb_entry_migration(pte_t pte)
3626 if (huge_pte_none(pte) || pte_present(pte))
3628 swp = pte_to_swp_entry(pte);
3629 if (non_swap_entry(swp) && is_migration_entry(swp))
3635 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3639 if (huge_pte_none(pte) || pte_present(pte))
3641 swp = pte_to_swp_entry(pte);
3642 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3648 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3649 struct vm_area_struct *vma)
3651 pte_t *src_pte, *dst_pte, entry, dst_entry;
3652 struct page *ptepage;
3655 struct hstate *h = hstate_vma(vma);
3656 unsigned long sz = huge_page_size(h);
3657 struct address_space *mapping = vma->vm_file->f_mapping;
3658 struct mmu_notifier_range range;
3661 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3664 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3667 mmu_notifier_invalidate_range_start(&range);
3670 * For shared mappings i_mmap_rwsem must be held to call
3671 * huge_pte_alloc, otherwise the returned ptep could go
3672 * away if part of a shared pmd and another thread calls
3675 i_mmap_lock_read(mapping);
3678 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3679 spinlock_t *src_ptl, *dst_ptl;
3680 src_pte = huge_pte_offset(src, addr, sz);
3683 dst_pte = huge_pte_alloc(dst, addr, sz);
3690 * If the pagetables are shared don't copy or take references.
3691 * dst_pte == src_pte is the common case of src/dest sharing.
3693 * However, src could have 'unshared' and dst shares with
3694 * another vma. If dst_pte !none, this implies sharing.
3695 * Check here before taking page table lock, and once again
3696 * after taking the lock below.
3698 dst_entry = huge_ptep_get(dst_pte);
3699 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3702 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3703 src_ptl = huge_pte_lockptr(h, src, src_pte);
3704 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3705 entry = huge_ptep_get(src_pte);
3706 dst_entry = huge_ptep_get(dst_pte);
3707 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3709 * Skip if src entry none. Also, skip in the
3710 * unlikely case dst entry !none as this implies
3711 * sharing with another vma.
3714 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3715 is_hugetlb_entry_hwpoisoned(entry))) {
3716 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3718 if (is_write_migration_entry(swp_entry) && cow) {
3720 * COW mappings require pages in both
3721 * parent and child to be set to read.
3723 make_migration_entry_read(&swp_entry);
3724 entry = swp_entry_to_pte(swp_entry);
3725 set_huge_swap_pte_at(src, addr, src_pte,
3728 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3732 * No need to notify as we are downgrading page
3733 * table protection not changing it to point
3736 * See Documentation/vm/mmu_notifier.rst
3738 huge_ptep_set_wrprotect(src, addr, src_pte);
3740 entry = huge_ptep_get(src_pte);
3741 ptepage = pte_page(entry);
3743 page_dup_rmap(ptepage, true);
3744 set_huge_pte_at(dst, addr, dst_pte, entry);
3745 hugetlb_count_add(pages_per_huge_page(h), dst);
3747 spin_unlock(src_ptl);
3748 spin_unlock(dst_ptl);
3752 mmu_notifier_invalidate_range_end(&range);
3754 i_mmap_unlock_read(mapping);
3759 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3760 unsigned long start, unsigned long end,
3761 struct page *ref_page)
3763 struct mm_struct *mm = vma->vm_mm;
3764 unsigned long address;
3769 struct hstate *h = hstate_vma(vma);
3770 unsigned long sz = huge_page_size(h);
3771 struct mmu_notifier_range range;
3773 WARN_ON(!is_vm_hugetlb_page(vma));
3774 BUG_ON(start & ~huge_page_mask(h));
3775 BUG_ON(end & ~huge_page_mask(h));
3778 * This is a hugetlb vma, all the pte entries should point
3781 tlb_change_page_size(tlb, sz);
3782 tlb_start_vma(tlb, vma);
3785 * If sharing possible, alert mmu notifiers of worst case.
3787 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
3789 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
3790 mmu_notifier_invalidate_range_start(&range);
3792 for (; address < end; address += sz) {
3793 ptep = huge_pte_offset(mm, address, sz);
3797 ptl = huge_pte_lock(h, mm, ptep);
3798 if (huge_pmd_unshare(mm, &address, ptep)) {
3801 * We just unmapped a page of PMDs by clearing a PUD.
3802 * The caller's TLB flush range should cover this area.
3807 pte = huge_ptep_get(ptep);
3808 if (huge_pte_none(pte)) {
3814 * Migrating hugepage or HWPoisoned hugepage is already
3815 * unmapped and its refcount is dropped, so just clear pte here.
3817 if (unlikely(!pte_present(pte))) {
3818 huge_pte_clear(mm, address, ptep, sz);
3823 page = pte_page(pte);
3825 * If a reference page is supplied, it is because a specific
3826 * page is being unmapped, not a range. Ensure the page we
3827 * are about to unmap is the actual page of interest.
3830 if (page != ref_page) {
3835 * Mark the VMA as having unmapped its page so that
3836 * future faults in this VMA will fail rather than
3837 * looking like data was lost
3839 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3842 pte = huge_ptep_get_and_clear(mm, address, ptep);
3843 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3844 if (huge_pte_dirty(pte))
3845 set_page_dirty(page);
3847 hugetlb_count_sub(pages_per_huge_page(h), mm);
3848 page_remove_rmap(page, true);
3851 tlb_remove_page_size(tlb, page, huge_page_size(h));
3853 * Bail out after unmapping reference page if supplied
3858 mmu_notifier_invalidate_range_end(&range);
3859 tlb_end_vma(tlb, vma);
3862 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
3863 struct vm_area_struct *vma, unsigned long start,
3864 unsigned long end, struct page *ref_page)
3866 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
3869 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3870 * test will fail on a vma being torn down, and not grab a page table
3871 * on its way out. We're lucky that the flag has such an appropriate
3872 * name, and can in fact be safely cleared here. We could clear it
3873 * before the __unmap_hugepage_range above, but all that's necessary
3874 * is to clear it before releasing the i_mmap_rwsem. This works
3875 * because in the context this is called, the VMA is about to be
3876 * destroyed and the i_mmap_rwsem is held.
3878 vma->vm_flags &= ~VM_MAYSHARE;
3881 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3882 unsigned long end, struct page *ref_page)
3884 struct mm_struct *mm;
3885 struct mmu_gather tlb;
3886 unsigned long tlb_start = start;
3887 unsigned long tlb_end = end;
3890 * If shared PMDs were possibly used within this vma range, adjust
3891 * start/end for worst case tlb flushing.
3892 * Note that we can not be sure if PMDs are shared until we try to
3893 * unmap pages. However, we want to make sure TLB flushing covers
3894 * the largest possible range.
3896 adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end);
3900 tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
3901 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3902 tlb_finish_mmu(&tlb, tlb_start, tlb_end);
3906 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3907 * mappping it owns the reserve page for. The intention is to unmap the page
3908 * from other VMAs and let the children be SIGKILLed if they are faulting the
3911 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
3912 struct page *page, unsigned long address)
3914 struct hstate *h = hstate_vma(vma);
3915 struct vm_area_struct *iter_vma;
3916 struct address_space *mapping;
3920 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3921 * from page cache lookup which is in HPAGE_SIZE units.
3923 address = address & huge_page_mask(h);
3924 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
3926 mapping = vma->vm_file->f_mapping;
3929 * Take the mapping lock for the duration of the table walk. As
3930 * this mapping should be shared between all the VMAs,
3931 * __unmap_hugepage_range() is called as the lock is already held
3933 i_mmap_lock_write(mapping);
3934 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3935 /* Do not unmap the current VMA */
3936 if (iter_vma == vma)
3940 * Shared VMAs have their own reserves and do not affect
3941 * MAP_PRIVATE accounting but it is possible that a shared
3942 * VMA is using the same page so check and skip such VMAs.
3944 if (iter_vma->vm_flags & VM_MAYSHARE)
3948 * Unmap the page from other VMAs without their own reserves.
3949 * They get marked to be SIGKILLed if they fault in these
3950 * areas. This is because a future no-page fault on this VMA
3951 * could insert a zeroed page instead of the data existing
3952 * from the time of fork. This would look like data corruption
3954 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
3955 unmap_hugepage_range(iter_vma, address,
3956 address + huge_page_size(h), page);
3958 i_mmap_unlock_write(mapping);
3962 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3963 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3964 * cannot race with other handlers or page migration.
3965 * Keep the pte_same checks anyway to make transition from the mutex easier.
3967 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3968 unsigned long address, pte_t *ptep,
3969 struct page *pagecache_page, spinlock_t *ptl)
3972 struct hstate *h = hstate_vma(vma);
3973 struct page *old_page, *new_page;
3974 int outside_reserve = 0;
3976 unsigned long haddr = address & huge_page_mask(h);
3977 struct mmu_notifier_range range;
3979 pte = huge_ptep_get(ptep);
3980 old_page = pte_page(pte);
3983 /* If no-one else is actually using this page, avoid the copy
3984 * and just make the page writable */
3985 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3986 page_move_anon_rmap(old_page, vma);
3987 set_huge_ptep_writable(vma, haddr, ptep);
3992 * If the process that created a MAP_PRIVATE mapping is about to
3993 * perform a COW due to a shared page count, attempt to satisfy
3994 * the allocation without using the existing reserves. The pagecache
3995 * page is used to determine if the reserve at this address was
3996 * consumed or not. If reserves were used, a partial faulted mapping
3997 * at the time of fork() could consume its reserves on COW instead
3998 * of the full address range.
4000 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4001 old_page != pagecache_page)
4002 outside_reserve = 1;
4007 * Drop page table lock as buddy allocator may be called. It will
4008 * be acquired again before returning to the caller, as expected.
4011 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4013 if (IS_ERR(new_page)) {
4015 * If a process owning a MAP_PRIVATE mapping fails to COW,
4016 * it is due to references held by a child and an insufficient
4017 * huge page pool. To guarantee the original mappers
4018 * reliability, unmap the page from child processes. The child
4019 * may get SIGKILLed if it later faults.
4021 if (outside_reserve) {
4023 BUG_ON(huge_pte_none(pte));
4024 unmap_ref_private(mm, vma, old_page, haddr);
4025 BUG_ON(huge_pte_none(pte));
4027 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4029 pte_same(huge_ptep_get(ptep), pte)))
4030 goto retry_avoidcopy;
4032 * race occurs while re-acquiring page table
4033 * lock, and our job is done.
4038 ret = vmf_error(PTR_ERR(new_page));
4039 goto out_release_old;
4043 * When the original hugepage is shared one, it does not have
4044 * anon_vma prepared.
4046 if (unlikely(anon_vma_prepare(vma))) {
4048 goto out_release_all;
4051 copy_user_huge_page(new_page, old_page, address, vma,
4052 pages_per_huge_page(h));
4053 __SetPageUptodate(new_page);
4055 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4056 haddr + huge_page_size(h));
4057 mmu_notifier_invalidate_range_start(&range);
4060 * Retake the page table lock to check for racing updates
4061 * before the page tables are altered
4064 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4065 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4066 ClearPagePrivate(new_page);
4069 huge_ptep_clear_flush(vma, haddr, ptep);
4070 mmu_notifier_invalidate_range(mm, range.start, range.end);
4071 set_huge_pte_at(mm, haddr, ptep,
4072 make_huge_pte(vma, new_page, 1));
4073 page_remove_rmap(old_page, true);
4074 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4075 set_page_huge_active(new_page);
4076 /* Make the old page be freed below */
4077 new_page = old_page;
4080 mmu_notifier_invalidate_range_end(&range);
4082 restore_reserve_on_error(h, vma, haddr, new_page);
4087 spin_lock(ptl); /* Caller expects lock to be held */
4091 /* Return the pagecache page at a given address within a VMA */
4092 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4093 struct vm_area_struct *vma, unsigned long address)
4095 struct address_space *mapping;
4098 mapping = vma->vm_file->f_mapping;
4099 idx = vma_hugecache_offset(h, vma, address);
4101 return find_lock_page(mapping, idx);
4105 * Return whether there is a pagecache page to back given address within VMA.
4106 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4108 static bool hugetlbfs_pagecache_present(struct hstate *h,
4109 struct vm_area_struct *vma, unsigned long address)
4111 struct address_space *mapping;
4115 mapping = vma->vm_file->f_mapping;
4116 idx = vma_hugecache_offset(h, vma, address);
4118 page = find_get_page(mapping, idx);
4121 return page != NULL;
4124 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4127 struct inode *inode = mapping->host;
4128 struct hstate *h = hstate_inode(inode);
4129 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4133 ClearPagePrivate(page);
4136 * set page dirty so that it will not be removed from cache/file
4137 * by non-hugetlbfs specific code paths.
4139 set_page_dirty(page);
4141 spin_lock(&inode->i_lock);
4142 inode->i_blocks += blocks_per_huge_page(h);
4143 spin_unlock(&inode->i_lock);
4147 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4148 struct vm_area_struct *vma,
4149 struct address_space *mapping, pgoff_t idx,
4150 unsigned long address, pte_t *ptep, unsigned int flags)
4152 struct hstate *h = hstate_vma(vma);
4153 vm_fault_t ret = VM_FAULT_SIGBUS;
4159 unsigned long haddr = address & huge_page_mask(h);
4160 bool new_page = false;
4163 * Currently, we are forced to kill the process in the event the
4164 * original mapper has unmapped pages from the child due to a failed
4165 * COW. Warn that such a situation has occurred as it may not be obvious
4167 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4168 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4174 * We can not race with truncation due to holding i_mmap_rwsem.
4175 * i_size is modified when holding i_mmap_rwsem, so check here
4176 * once for faults beyond end of file.
4178 size = i_size_read(mapping->host) >> huge_page_shift(h);
4183 page = find_lock_page(mapping, idx);
4186 * Check for page in userfault range
4188 if (userfaultfd_missing(vma)) {
4190 struct vm_fault vmf = {
4195 * Hard to debug if it ends up being
4196 * used by a callee that assumes
4197 * something about the other
4198 * uninitialized fields... same as in
4204 * hugetlb_fault_mutex and i_mmap_rwsem must be
4205 * dropped before handling userfault. Reacquire
4206 * after handling fault to make calling code simpler.
4208 hash = hugetlb_fault_mutex_hash(mapping, idx);
4209 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4210 i_mmap_unlock_read(mapping);
4211 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4212 i_mmap_lock_read(mapping);
4213 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4217 page = alloc_huge_page(vma, haddr, 0);
4220 * Returning error will result in faulting task being
4221 * sent SIGBUS. The hugetlb fault mutex prevents two
4222 * tasks from racing to fault in the same page which
4223 * could result in false unable to allocate errors.
4224 * Page migration does not take the fault mutex, but
4225 * does a clear then write of pte's under page table
4226 * lock. Page fault code could race with migration,
4227 * notice the clear pte and try to allocate a page
4228 * here. Before returning error, get ptl and make
4229 * sure there really is no pte entry.
4231 ptl = huge_pte_lock(h, mm, ptep);
4232 if (!huge_pte_none(huge_ptep_get(ptep))) {
4238 ret = vmf_error(PTR_ERR(page));
4241 clear_huge_page(page, address, pages_per_huge_page(h));
4242 __SetPageUptodate(page);
4245 if (vma->vm_flags & VM_MAYSHARE) {
4246 int err = huge_add_to_page_cache(page, mapping, idx);
4255 if (unlikely(anon_vma_prepare(vma))) {
4257 goto backout_unlocked;
4263 * If memory error occurs between mmap() and fault, some process
4264 * don't have hwpoisoned swap entry for errored virtual address.
4265 * So we need to block hugepage fault by PG_hwpoison bit check.
4267 if (unlikely(PageHWPoison(page))) {
4268 ret = VM_FAULT_HWPOISON |
4269 VM_FAULT_SET_HINDEX(hstate_index(h));
4270 goto backout_unlocked;
4275 * If we are going to COW a private mapping later, we examine the
4276 * pending reservations for this page now. This will ensure that
4277 * any allocations necessary to record that reservation occur outside
4280 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4281 if (vma_needs_reservation(h, vma, haddr) < 0) {
4283 goto backout_unlocked;
4285 /* Just decrements count, does not deallocate */
4286 vma_end_reservation(h, vma, haddr);
4289 ptl = huge_pte_lock(h, mm, ptep);
4291 if (!huge_pte_none(huge_ptep_get(ptep)))
4295 ClearPagePrivate(page);
4296 hugepage_add_new_anon_rmap(page, vma, haddr);
4298 page_dup_rmap(page, true);
4299 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4300 && (vma->vm_flags & VM_SHARED)));
4301 set_huge_pte_at(mm, haddr, ptep, new_pte);
4303 hugetlb_count_add(pages_per_huge_page(h), mm);
4304 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4305 /* Optimization, do the COW without a second fault */
4306 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4312 * Only make newly allocated pages active. Existing pages found
4313 * in the pagecache could be !page_huge_active() if they have been
4314 * isolated for migration.
4317 set_page_huge_active(page);
4327 restore_reserve_on_error(h, vma, haddr, page);
4333 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4335 unsigned long key[2];
4338 key[0] = (unsigned long) mapping;
4341 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4343 return hash & (num_fault_mutexes - 1);
4347 * For uniprocesor systems we always use a single mutex, so just
4348 * return 0 and avoid the hashing overhead.
4350 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4356 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4357 unsigned long address, unsigned int flags)
4364 struct page *page = NULL;
4365 struct page *pagecache_page = NULL;
4366 struct hstate *h = hstate_vma(vma);
4367 struct address_space *mapping;
4368 int need_wait_lock = 0;
4369 unsigned long haddr = address & huge_page_mask(h);
4371 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4374 * Since we hold no locks, ptep could be stale. That is
4375 * OK as we are only making decisions based on content and
4376 * not actually modifying content here.
4378 entry = huge_ptep_get(ptep);
4379 if (unlikely(is_hugetlb_entry_migration(entry))) {
4380 migration_entry_wait_huge(vma, mm, ptep);
4382 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4383 return VM_FAULT_HWPOISON_LARGE |
4384 VM_FAULT_SET_HINDEX(hstate_index(h));
4386 ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
4388 return VM_FAULT_OOM;
4392 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4393 * until finished with ptep. This serves two purposes:
4394 * 1) It prevents huge_pmd_unshare from being called elsewhere
4395 * and making the ptep no longer valid.
4396 * 2) It synchronizes us with i_size modifications during truncation.
4398 * ptep could have already be assigned via huge_pte_offset. That
4399 * is OK, as huge_pte_alloc will return the same value unless
4400 * something has changed.
4402 mapping = vma->vm_file->f_mapping;
4403 i_mmap_lock_read(mapping);
4404 ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
4406 i_mmap_unlock_read(mapping);
4407 return VM_FAULT_OOM;
4411 * Serialize hugepage allocation and instantiation, so that we don't
4412 * get spurious allocation failures if two CPUs race to instantiate
4413 * the same page in the page cache.
4415 idx = vma_hugecache_offset(h, vma, haddr);
4416 hash = hugetlb_fault_mutex_hash(mapping, idx);
4417 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4419 entry = huge_ptep_get(ptep);
4420 if (huge_pte_none(entry)) {
4421 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4428 * entry could be a migration/hwpoison entry at this point, so this
4429 * check prevents the kernel from going below assuming that we have
4430 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4431 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4434 if (!pte_present(entry))
4438 * If we are going to COW the mapping later, we examine the pending
4439 * reservations for this page now. This will ensure that any
4440 * allocations necessary to record that reservation occur outside the
4441 * spinlock. For private mappings, we also lookup the pagecache
4442 * page now as it is used to determine if a reservation has been
4445 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4446 if (vma_needs_reservation(h, vma, haddr) < 0) {
4450 /* Just decrements count, does not deallocate */
4451 vma_end_reservation(h, vma, haddr);
4453 if (!(vma->vm_flags & VM_MAYSHARE))
4454 pagecache_page = hugetlbfs_pagecache_page(h,
4458 ptl = huge_pte_lock(h, mm, ptep);
4460 /* Check for a racing update before calling hugetlb_cow */
4461 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4465 * hugetlb_cow() requires page locks of pte_page(entry) and
4466 * pagecache_page, so here we need take the former one
4467 * when page != pagecache_page or !pagecache_page.
4469 page = pte_page(entry);
4470 if (page != pagecache_page)
4471 if (!trylock_page(page)) {
4478 if (flags & FAULT_FLAG_WRITE) {
4479 if (!huge_pte_write(entry)) {
4480 ret = hugetlb_cow(mm, vma, address, ptep,
4481 pagecache_page, ptl);
4484 entry = huge_pte_mkdirty(entry);
4486 entry = pte_mkyoung(entry);
4487 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4488 flags & FAULT_FLAG_WRITE))
4489 update_mmu_cache(vma, haddr, ptep);
4491 if (page != pagecache_page)
4497 if (pagecache_page) {
4498 unlock_page(pagecache_page);
4499 put_page(pagecache_page);
4502 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4503 i_mmap_unlock_read(mapping);
4505 * Generally it's safe to hold refcount during waiting page lock. But
4506 * here we just wait to defer the next page fault to avoid busy loop and
4507 * the page is not used after unlocked before returning from the current
4508 * page fault. So we are safe from accessing freed page, even if we wait
4509 * here without taking refcount.
4512 wait_on_page_locked(page);
4517 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4518 * modifications for huge pages.
4520 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4522 struct vm_area_struct *dst_vma,
4523 unsigned long dst_addr,
4524 unsigned long src_addr,
4525 struct page **pagep)
4527 struct address_space *mapping;
4530 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4531 struct hstate *h = hstate_vma(dst_vma);
4539 page = alloc_huge_page(dst_vma, dst_addr, 0);
4543 ret = copy_huge_page_from_user(page,
4544 (const void __user *) src_addr,
4545 pages_per_huge_page(h), false);
4547 /* fallback to copy_from_user outside mmap_sem */
4548 if (unlikely(ret)) {
4551 /* don't free the page */
4560 * The memory barrier inside __SetPageUptodate makes sure that
4561 * preceding stores to the page contents become visible before
4562 * the set_pte_at() write.
4564 __SetPageUptodate(page);
4566 mapping = dst_vma->vm_file->f_mapping;
4567 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4570 * If shared, add to page cache
4573 size = i_size_read(mapping->host) >> huge_page_shift(h);
4576 goto out_release_nounlock;
4579 * Serialization between remove_inode_hugepages() and
4580 * huge_add_to_page_cache() below happens through the
4581 * hugetlb_fault_mutex_table that here must be hold by
4584 ret = huge_add_to_page_cache(page, mapping, idx);
4586 goto out_release_nounlock;
4589 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4593 * Recheck the i_size after holding PT lock to make sure not
4594 * to leave any page mapped (as page_mapped()) beyond the end
4595 * of the i_size (remove_inode_hugepages() is strict about
4596 * enforcing that). If we bail out here, we'll also leave a
4597 * page in the radix tree in the vm_shared case beyond the end
4598 * of the i_size, but remove_inode_hugepages() will take care
4599 * of it as soon as we drop the hugetlb_fault_mutex_table.
4601 size = i_size_read(mapping->host) >> huge_page_shift(h);
4604 goto out_release_unlock;
4607 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4608 goto out_release_unlock;
4611 page_dup_rmap(page, true);
4613 ClearPagePrivate(page);
4614 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4617 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4618 if (dst_vma->vm_flags & VM_WRITE)
4619 _dst_pte = huge_pte_mkdirty(_dst_pte);
4620 _dst_pte = pte_mkyoung(_dst_pte);
4622 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4624 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4625 dst_vma->vm_flags & VM_WRITE);
4626 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4628 /* No need to invalidate - it was non-present before */
4629 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4632 set_page_huge_active(page);
4642 out_release_nounlock:
4647 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4648 struct page **pages, struct vm_area_struct **vmas,
4649 unsigned long *position, unsigned long *nr_pages,
4650 long i, unsigned int flags, int *locked)
4652 unsigned long pfn_offset;
4653 unsigned long vaddr = *position;
4654 unsigned long remainder = *nr_pages;
4655 struct hstate *h = hstate_vma(vma);
4658 while (vaddr < vma->vm_end && remainder) {
4660 spinlock_t *ptl = NULL;
4665 * If we have a pending SIGKILL, don't keep faulting pages and
4666 * potentially allocating memory.
4668 if (fatal_signal_pending(current)) {
4674 * Some archs (sparc64, sh*) have multiple pte_ts to
4675 * each hugepage. We have to make sure we get the
4676 * first, for the page indexing below to work.
4678 * Note that page table lock is not held when pte is null.
4680 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4683 ptl = huge_pte_lock(h, mm, pte);
4684 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4687 * When coredumping, it suits get_dump_page if we just return
4688 * an error where there's an empty slot with no huge pagecache
4689 * to back it. This way, we avoid allocating a hugepage, and
4690 * the sparse dumpfile avoids allocating disk blocks, but its
4691 * huge holes still show up with zeroes where they need to be.
4693 if (absent && (flags & FOLL_DUMP) &&
4694 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4702 * We need call hugetlb_fault for both hugepages under migration
4703 * (in which case hugetlb_fault waits for the migration,) and
4704 * hwpoisoned hugepages (in which case we need to prevent the
4705 * caller from accessing to them.) In order to do this, we use
4706 * here is_swap_pte instead of is_hugetlb_entry_migration and
4707 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4708 * both cases, and because we can't follow correct pages
4709 * directly from any kind of swap entries.
4711 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4712 ((flags & FOLL_WRITE) &&
4713 !huge_pte_write(huge_ptep_get(pte)))) {
4715 unsigned int fault_flags = 0;
4719 if (flags & FOLL_WRITE)
4720 fault_flags |= FAULT_FLAG_WRITE;
4722 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4723 FAULT_FLAG_KILLABLE;
4724 if (flags & FOLL_NOWAIT)
4725 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4726 FAULT_FLAG_RETRY_NOWAIT;
4727 if (flags & FOLL_TRIED) {
4729 * Note: FAULT_FLAG_ALLOW_RETRY and
4730 * FAULT_FLAG_TRIED can co-exist
4732 fault_flags |= FAULT_FLAG_TRIED;
4734 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4735 if (ret & VM_FAULT_ERROR) {
4736 err = vm_fault_to_errno(ret, flags);
4740 if (ret & VM_FAULT_RETRY) {
4742 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4746 * VM_FAULT_RETRY must not return an
4747 * error, it will return zero
4750 * No need to update "position" as the
4751 * caller will not check it after
4752 * *nr_pages is set to 0.
4759 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4760 page = pte_page(huge_ptep_get(pte));
4763 * If subpage information not requested, update counters
4764 * and skip the same_page loop below.
4766 if (!pages && !vmas && !pfn_offset &&
4767 (vaddr + huge_page_size(h) < vma->vm_end) &&
4768 (remainder >= pages_per_huge_page(h))) {
4769 vaddr += huge_page_size(h);
4770 remainder -= pages_per_huge_page(h);
4771 i += pages_per_huge_page(h);
4778 pages[i] = mem_map_offset(page, pfn_offset);
4780 * try_grab_page() should always succeed here, because:
4781 * a) we hold the ptl lock, and b) we've just checked
4782 * that the huge page is present in the page tables. If
4783 * the huge page is present, then the tail pages must
4784 * also be present. The ptl prevents the head page and
4785 * tail pages from being rearranged in any way. So this
4786 * page must be available at this point, unless the page
4787 * refcount overflowed:
4789 if (WARN_ON_ONCE(!try_grab_page(pages[i], flags))) {
4804 if (vaddr < vma->vm_end && remainder &&
4805 pfn_offset < pages_per_huge_page(h)) {
4807 * We use pfn_offset to avoid touching the pageframes
4808 * of this compound page.
4814 *nr_pages = remainder;
4816 * setting position is actually required only if remainder is
4817 * not zero but it's faster not to add a "if (remainder)"
4825 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4827 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4830 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4833 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4834 unsigned long address, unsigned long end, pgprot_t newprot)
4836 struct mm_struct *mm = vma->vm_mm;
4837 unsigned long start = address;
4840 struct hstate *h = hstate_vma(vma);
4841 unsigned long pages = 0;
4842 bool shared_pmd = false;
4843 struct mmu_notifier_range range;
4846 * In the case of shared PMDs, the area to flush could be beyond
4847 * start/end. Set range.start/range.end to cover the maximum possible
4848 * range if PMD sharing is possible.
4850 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
4851 0, vma, mm, start, end);
4852 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4854 BUG_ON(address >= end);
4855 flush_cache_range(vma, range.start, range.end);
4857 mmu_notifier_invalidate_range_start(&range);
4858 i_mmap_lock_write(vma->vm_file->f_mapping);
4859 for (; address < end; address += huge_page_size(h)) {
4861 ptep = huge_pte_offset(mm, address, huge_page_size(h));
4864 ptl = huge_pte_lock(h, mm, ptep);
4865 if (huge_pmd_unshare(mm, &address, ptep)) {
4871 pte = huge_ptep_get(ptep);
4872 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
4876 if (unlikely(is_hugetlb_entry_migration(pte))) {
4877 swp_entry_t entry = pte_to_swp_entry(pte);
4879 if (is_write_migration_entry(entry)) {
4882 make_migration_entry_read(&entry);
4883 newpte = swp_entry_to_pte(entry);
4884 set_huge_swap_pte_at(mm, address, ptep,
4885 newpte, huge_page_size(h));
4891 if (!huge_pte_none(pte)) {
4894 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
4895 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
4896 pte = arch_make_huge_pte(pte, vma, NULL, 0);
4897 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
4903 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4904 * may have cleared our pud entry and done put_page on the page table:
4905 * once we release i_mmap_rwsem, another task can do the final put_page
4906 * and that page table be reused and filled with junk. If we actually
4907 * did unshare a page of pmds, flush the range corresponding to the pud.
4910 flush_hugetlb_tlb_range(vma, range.start, range.end);
4912 flush_hugetlb_tlb_range(vma, start, end);
4914 * No need to call mmu_notifier_invalidate_range() we are downgrading
4915 * page table protection not changing it to point to a new page.
4917 * See Documentation/vm/mmu_notifier.rst
4919 i_mmap_unlock_write(vma->vm_file->f_mapping);
4920 mmu_notifier_invalidate_range_end(&range);
4922 return pages << h->order;
4925 int hugetlb_reserve_pages(struct inode *inode,
4927 struct vm_area_struct *vma,
4928 vm_flags_t vm_flags)
4930 long ret, chg, add = -1;
4931 struct hstate *h = hstate_inode(inode);
4932 struct hugepage_subpool *spool = subpool_inode(inode);
4933 struct resv_map *resv_map;
4934 struct hugetlb_cgroup *h_cg = NULL;
4935 long gbl_reserve, regions_needed = 0;
4937 /* This should never happen */
4939 VM_WARN(1, "%s called with a negative range\n", __func__);
4944 * Only apply hugepage reservation if asked. At fault time, an
4945 * attempt will be made for VM_NORESERVE to allocate a page
4946 * without using reserves
4948 if (vm_flags & VM_NORESERVE)
4952 * Shared mappings base their reservation on the number of pages that
4953 * are already allocated on behalf of the file. Private mappings need
4954 * to reserve the full area even if read-only as mprotect() may be
4955 * called to make the mapping read-write. Assume !vma is a shm mapping
4957 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4959 * resv_map can not be NULL as hugetlb_reserve_pages is only
4960 * called for inodes for which resv_maps were created (see
4961 * hugetlbfs_get_inode).
4963 resv_map = inode_resv_map(inode);
4965 chg = region_chg(resv_map, from, to, ®ions_needed);
4968 /* Private mapping. */
4969 resv_map = resv_map_alloc();
4975 set_vma_resv_map(vma, resv_map);
4976 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
4984 ret = hugetlb_cgroup_charge_cgroup_rsvd(
4985 hstate_index(h), chg * pages_per_huge_page(h), &h_cg);
4992 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
4993 /* For private mappings, the hugetlb_cgroup uncharge info hangs
4996 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5000 * There must be enough pages in the subpool for the mapping. If
5001 * the subpool has a minimum size, there may be some global
5002 * reservations already in place (gbl_reserve).
5004 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5005 if (gbl_reserve < 0) {
5007 goto out_uncharge_cgroup;
5011 * Check enough hugepages are available for the reservation.
5012 * Hand the pages back to the subpool if there are not
5014 ret = hugetlb_acct_memory(h, gbl_reserve);
5020 * Account for the reservations made. Shared mappings record regions
5021 * that have reservations as they are shared by multiple VMAs.
5022 * When the last VMA disappears, the region map says how much
5023 * the reservation was and the page cache tells how much of
5024 * the reservation was consumed. Private mappings are per-VMA and
5025 * only the consumed reservations are tracked. When the VMA
5026 * disappears, the original reservation is the VMA size and the
5027 * consumed reservations are stored in the map. Hence, nothing
5028 * else has to be done for private mappings here
5030 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5031 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5033 if (unlikely(add < 0)) {
5034 hugetlb_acct_memory(h, -gbl_reserve);
5036 } else if (unlikely(chg > add)) {
5038 * pages in this range were added to the reserve
5039 * map between region_chg and region_add. This
5040 * indicates a race with alloc_huge_page. Adjust
5041 * the subpool and reserve counts modified above
5042 * based on the difference.
5046 hugetlb_cgroup_uncharge_cgroup_rsvd(
5048 (chg - add) * pages_per_huge_page(h), h_cg);
5050 rsv_adjust = hugepage_subpool_put_pages(spool,
5052 hugetlb_acct_memory(h, -rsv_adjust);
5057 /* put back original number of pages, chg */
5058 (void)hugepage_subpool_put_pages(spool, chg);
5059 out_uncharge_cgroup:
5060 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5061 chg * pages_per_huge_page(h), h_cg);
5063 if (!vma || vma->vm_flags & VM_MAYSHARE)
5064 /* Only call region_abort if the region_chg succeeded but the
5065 * region_add failed or didn't run.
5067 if (chg >= 0 && add < 0)
5068 region_abort(resv_map, from, to, regions_needed);
5069 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5070 kref_put(&resv_map->refs, resv_map_release);
5074 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5077 struct hstate *h = hstate_inode(inode);
5078 struct resv_map *resv_map = inode_resv_map(inode);
5080 struct hugepage_subpool *spool = subpool_inode(inode);
5084 * Since this routine can be called in the evict inode path for all
5085 * hugetlbfs inodes, resv_map could be NULL.
5088 chg = region_del(resv_map, start, end);
5090 * region_del() can fail in the rare case where a region
5091 * must be split and another region descriptor can not be
5092 * allocated. If end == LONG_MAX, it will not fail.
5098 spin_lock(&inode->i_lock);
5099 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5100 spin_unlock(&inode->i_lock);
5103 * If the subpool has a minimum size, the number of global
5104 * reservations to be released may be adjusted.
5106 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5107 hugetlb_acct_memory(h, -gbl_reserve);
5112 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5113 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5114 struct vm_area_struct *vma,
5115 unsigned long addr, pgoff_t idx)
5117 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5119 unsigned long sbase = saddr & PUD_MASK;
5120 unsigned long s_end = sbase + PUD_SIZE;
5122 /* Allow segments to share if only one is marked locked */
5123 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5124 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5127 * match the virtual addresses, permission and the alignment of the
5130 if (pmd_index(addr) != pmd_index(saddr) ||
5131 vm_flags != svm_flags ||
5132 sbase < svma->vm_start || svma->vm_end < s_end)
5138 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5140 unsigned long base = addr & PUD_MASK;
5141 unsigned long end = base + PUD_SIZE;
5144 * check on proper vm_flags and page table alignment
5146 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5152 * Determine if start,end range within vma could be mapped by shared pmd.
5153 * If yes, adjust start and end to cover range associated with possible
5154 * shared pmd mappings.
5156 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5157 unsigned long *start, unsigned long *end)
5159 unsigned long check_addr;
5161 if (!(vma->vm_flags & VM_MAYSHARE))
5164 for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) {
5165 unsigned long a_start = check_addr & PUD_MASK;
5166 unsigned long a_end = a_start + PUD_SIZE;
5169 * If sharing is possible, adjust start/end if necessary.
5171 if (range_in_vma(vma, a_start, a_end)) {
5172 if (a_start < *start)
5181 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5182 * and returns the corresponding pte. While this is not necessary for the
5183 * !shared pmd case because we can allocate the pmd later as well, it makes the
5184 * code much cleaner.
5186 * This routine must be called with i_mmap_rwsem held in at least read mode.
5187 * For hugetlbfs, this prevents removal of any page table entries associated
5188 * with the address space. This is important as we are setting up sharing
5189 * based on existing page table entries (mappings).
5191 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5193 struct vm_area_struct *vma = find_vma(mm, addr);
5194 struct address_space *mapping = vma->vm_file->f_mapping;
5195 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5197 struct vm_area_struct *svma;
5198 unsigned long saddr;
5203 if (!vma_shareable(vma, addr))
5204 return (pte_t *)pmd_alloc(mm, pud, addr);
5206 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5210 saddr = page_table_shareable(svma, vma, addr, idx);
5212 spte = huge_pte_offset(svma->vm_mm, saddr,
5213 vma_mmu_pagesize(svma));
5215 get_page(virt_to_page(spte));
5224 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5225 if (pud_none(*pud)) {
5226 pud_populate(mm, pud,
5227 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5230 put_page(virt_to_page(spte));
5234 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5239 * unmap huge page backed by shared pte.
5241 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5242 * indicated by page_count > 1, unmap is achieved by clearing pud and
5243 * decrementing the ref count. If count == 1, the pte page is not shared.
5245 * Called with page table lock held and i_mmap_rwsem held in write mode.
5247 * returns: 1 successfully unmapped a shared pte page
5248 * 0 the underlying pte page is not shared, or it is the last user
5250 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
5252 pgd_t *pgd = pgd_offset(mm, *addr);
5253 p4d_t *p4d = p4d_offset(pgd, *addr);
5254 pud_t *pud = pud_offset(p4d, *addr);
5256 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5257 if (page_count(virt_to_page(ptep)) == 1)
5261 put_page(virt_to_page(ptep));
5263 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5266 #define want_pmd_share() (1)
5267 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5268 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5273 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
5278 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5279 unsigned long *start, unsigned long *end)
5282 #define want_pmd_share() (0)
5283 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5285 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5286 pte_t *huge_pte_alloc(struct mm_struct *mm,
5287 unsigned long addr, unsigned long sz)
5294 pgd = pgd_offset(mm, addr);
5295 p4d = p4d_alloc(mm, pgd, addr);
5298 pud = pud_alloc(mm, p4d, addr);
5300 if (sz == PUD_SIZE) {
5303 BUG_ON(sz != PMD_SIZE);
5304 if (want_pmd_share() && pud_none(*pud))
5305 pte = huge_pmd_share(mm, addr, pud);
5307 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5310 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5316 * huge_pte_offset() - Walk the page table to resolve the hugepage
5317 * entry at address @addr
5319 * Return: Pointer to page table or swap entry (PUD or PMD) for
5320 * address @addr, or NULL if a p*d_none() entry is encountered and the
5321 * size @sz doesn't match the hugepage size at this level of the page
5324 pte_t *huge_pte_offset(struct mm_struct *mm,
5325 unsigned long addr, unsigned long sz)
5332 pgd = pgd_offset(mm, addr);
5333 if (!pgd_present(*pgd))
5335 p4d = p4d_offset(pgd, addr);
5336 if (!p4d_present(*p4d))
5339 pud = pud_offset(p4d, addr);
5340 if (sz != PUD_SIZE && pud_none(*pud))
5342 /* hugepage or swap? */
5343 if (pud_huge(*pud) || !pud_present(*pud))
5344 return (pte_t *)pud;
5346 pmd = pmd_offset(pud, addr);
5347 if (sz != PMD_SIZE && pmd_none(*pmd))
5349 /* hugepage or swap? */
5350 if (pmd_huge(*pmd) || !pmd_present(*pmd))
5351 return (pte_t *)pmd;
5356 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5359 * These functions are overwritable if your architecture needs its own
5362 struct page * __weak
5363 follow_huge_addr(struct mm_struct *mm, unsigned long address,
5366 return ERR_PTR(-EINVAL);
5369 struct page * __weak
5370 follow_huge_pd(struct vm_area_struct *vma,
5371 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5373 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5377 struct page * __weak
5378 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5379 pmd_t *pmd, int flags)
5381 struct page *page = NULL;
5385 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5386 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5387 (FOLL_PIN | FOLL_GET)))
5391 ptl = pmd_lockptr(mm, pmd);
5394 * make sure that the address range covered by this pmd is not
5395 * unmapped from other threads.
5397 if (!pmd_huge(*pmd))
5399 pte = huge_ptep_get((pte_t *)pmd);
5400 if (pte_present(pte)) {
5401 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5403 * try_grab_page() should always succeed here, because: a) we
5404 * hold the pmd (ptl) lock, and b) we've just checked that the
5405 * huge pmd (head) page is present in the page tables. The ptl
5406 * prevents the head page and tail pages from being rearranged
5407 * in any way. So this page must be available at this point,
5408 * unless the page refcount overflowed:
5410 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5415 if (is_hugetlb_entry_migration(pte)) {
5417 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5421 * hwpoisoned entry is treated as no_page_table in
5422 * follow_page_mask().
5430 struct page * __weak
5431 follow_huge_pud(struct mm_struct *mm, unsigned long address,
5432 pud_t *pud, int flags)
5434 if (flags & (FOLL_GET | FOLL_PIN))
5437 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5440 struct page * __weak
5441 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5443 if (flags & (FOLL_GET | FOLL_PIN))
5446 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5449 bool isolate_huge_page(struct page *page, struct list_head *list)
5453 VM_BUG_ON_PAGE(!PageHead(page), page);
5454 spin_lock(&hugetlb_lock);
5455 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
5459 clear_page_huge_active(page);
5460 list_move_tail(&page->lru, list);
5462 spin_unlock(&hugetlb_lock);
5466 void putback_active_hugepage(struct page *page)
5468 VM_BUG_ON_PAGE(!PageHead(page), page);
5469 spin_lock(&hugetlb_lock);
5470 set_page_huge_active(page);
5471 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5472 spin_unlock(&hugetlb_lock);
5476 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5478 struct hstate *h = page_hstate(oldpage);
5480 hugetlb_cgroup_migrate(oldpage, newpage);
5481 set_page_owner_migrate_reason(newpage, reason);
5484 * transfer temporary state of the new huge page. This is
5485 * reverse to other transitions because the newpage is going to
5486 * be final while the old one will be freed so it takes over
5487 * the temporary status.
5489 * Also note that we have to transfer the per-node surplus state
5490 * here as well otherwise the global surplus count will not match
5493 if (PageHugeTemporary(newpage)) {
5494 int old_nid = page_to_nid(oldpage);
5495 int new_nid = page_to_nid(newpage);
5497 SetPageHugeTemporary(oldpage);
5498 ClearPageHugeTemporary(newpage);
5500 spin_lock(&hugetlb_lock);
5501 if (h->surplus_huge_pages_node[old_nid]) {
5502 h->surplus_huge_pages_node[old_nid]--;
5503 h->surplus_huge_pages_node[new_nid]++;
5505 spin_unlock(&hugetlb_lock);