1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/sched/mm.h>
23 #include <linux/mmdebug.h>
24 #include <linux/sched/signal.h>
25 #include <linux/rmap.h>
26 #include <linux/string_helpers.h>
27 #include <linux/swap.h>
28 #include <linux/swapops.h>
29 #include <linux/jhash.h>
30 #include <linux/numa.h>
31 #include <linux/llist.h>
32 #include <linux/cma.h>
35 #include <asm/pgalloc.h>
39 #include <linux/hugetlb.h>
40 #include <linux/hugetlb_cgroup.h>
41 #include <linux/node.h>
42 #include <linux/userfaultfd_k.h>
43 #include <linux/page_owner.h>
46 int hugetlb_max_hstate __read_mostly;
47 unsigned int default_hstate_idx;
48 struct hstate hstates[HUGE_MAX_HSTATE];
51 static struct cma *hugetlb_cma[MAX_NUMNODES];
53 static unsigned long hugetlb_cma_size __initdata;
56 * Minimum page order among possible hugepage sizes, set to a proper value
59 static unsigned int minimum_order __read_mostly = UINT_MAX;
61 __initdata LIST_HEAD(huge_boot_pages);
63 /* for command line parsing */
64 static struct hstate * __initdata parsed_hstate;
65 static unsigned long __initdata default_hstate_max_huge_pages;
66 static bool __initdata parsed_valid_hugepagesz = true;
67 static bool __initdata parsed_default_hugepagesz;
70 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
71 * free_huge_pages, and surplus_huge_pages.
73 DEFINE_SPINLOCK(hugetlb_lock);
76 * Serializes faults on the same logical page. This is used to
77 * prevent spurious OOMs when the hugepage pool is fully utilized.
79 static int num_fault_mutexes;
80 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
82 /* Forward declaration */
83 static int hugetlb_acct_memory(struct hstate *h, long delta);
85 static inline bool subpool_is_free(struct hugepage_subpool *spool)
89 if (spool->max_hpages != -1)
90 return spool->used_hpages == 0;
91 if (spool->min_hpages != -1)
92 return spool->rsv_hpages == spool->min_hpages;
97 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
99 spin_unlock(&spool->lock);
101 /* If no pages are used, and no other handles to the subpool
102 * remain, give up any reservations based on minimum size and
103 * free the subpool */
104 if (subpool_is_free(spool)) {
105 if (spool->min_hpages != -1)
106 hugetlb_acct_memory(spool->hstate,
112 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
115 struct hugepage_subpool *spool;
117 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
121 spin_lock_init(&spool->lock);
123 spool->max_hpages = max_hpages;
125 spool->min_hpages = min_hpages;
127 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
131 spool->rsv_hpages = min_hpages;
136 void hugepage_put_subpool(struct hugepage_subpool *spool)
138 spin_lock(&spool->lock);
139 BUG_ON(!spool->count);
141 unlock_or_release_subpool(spool);
145 * Subpool accounting for allocating and reserving pages.
146 * Return -ENOMEM if there are not enough resources to satisfy the
147 * request. Otherwise, return the number of pages by which the
148 * global pools must be adjusted (upward). The returned value may
149 * only be different than the passed value (delta) in the case where
150 * a subpool minimum size must be maintained.
152 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
160 spin_lock(&spool->lock);
162 if (spool->max_hpages != -1) { /* maximum size accounting */
163 if ((spool->used_hpages + delta) <= spool->max_hpages)
164 spool->used_hpages += delta;
171 /* minimum size accounting */
172 if (spool->min_hpages != -1 && spool->rsv_hpages) {
173 if (delta > spool->rsv_hpages) {
175 * Asking for more reserves than those already taken on
176 * behalf of subpool. Return difference.
178 ret = delta - spool->rsv_hpages;
179 spool->rsv_hpages = 0;
181 ret = 0; /* reserves already accounted for */
182 spool->rsv_hpages -= delta;
187 spin_unlock(&spool->lock);
192 * Subpool accounting for freeing and unreserving pages.
193 * Return the number of global page reservations that must be dropped.
194 * The return value may only be different than the passed value (delta)
195 * in the case where a subpool minimum size must be maintained.
197 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
205 spin_lock(&spool->lock);
207 if (spool->max_hpages != -1) /* maximum size accounting */
208 spool->used_hpages -= delta;
210 /* minimum size accounting */
211 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
212 if (spool->rsv_hpages + delta <= spool->min_hpages)
215 ret = spool->rsv_hpages + delta - spool->min_hpages;
217 spool->rsv_hpages += delta;
218 if (spool->rsv_hpages > spool->min_hpages)
219 spool->rsv_hpages = spool->min_hpages;
223 * If hugetlbfs_put_super couldn't free spool due to an outstanding
224 * quota reference, free it now.
226 unlock_or_release_subpool(spool);
231 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
233 return HUGETLBFS_SB(inode->i_sb)->spool;
236 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
238 return subpool_inode(file_inode(vma->vm_file));
241 /* Helper that removes a struct file_region from the resv_map cache and returns
244 static struct file_region *
245 get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
247 struct file_region *nrg = NULL;
249 VM_BUG_ON(resv->region_cache_count <= 0);
251 resv->region_cache_count--;
252 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
253 list_del(&nrg->link);
261 static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
262 struct file_region *rg)
264 #ifdef CONFIG_CGROUP_HUGETLB
265 nrg->reservation_counter = rg->reservation_counter;
272 /* Helper that records hugetlb_cgroup uncharge info. */
273 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
275 struct resv_map *resv,
276 struct file_region *nrg)
278 #ifdef CONFIG_CGROUP_HUGETLB
280 nrg->reservation_counter =
281 &h_cg->rsvd_hugepage[hstate_index(h)];
282 nrg->css = &h_cg->css;
284 * The caller will hold exactly one h_cg->css reference for the
285 * whole contiguous reservation region. But this area might be
286 * scattered when there are already some file_regions reside in
287 * it. As a result, many file_regions may share only one css
288 * reference. In order to ensure that one file_region must hold
289 * exactly one h_cg->css reference, we should do css_get for
290 * each file_region and leave the reference held by caller
294 if (!resv->pages_per_hpage)
295 resv->pages_per_hpage = pages_per_huge_page(h);
296 /* pages_per_hpage should be the same for all entries in
299 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
301 nrg->reservation_counter = NULL;
307 static void put_uncharge_info(struct file_region *rg)
309 #ifdef CONFIG_CGROUP_HUGETLB
315 static bool has_same_uncharge_info(struct file_region *rg,
316 struct file_region *org)
318 #ifdef CONFIG_CGROUP_HUGETLB
320 rg->reservation_counter == org->reservation_counter &&
328 static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
330 struct file_region *nrg = NULL, *prg = NULL;
332 prg = list_prev_entry(rg, link);
333 if (&prg->link != &resv->regions && prg->to == rg->from &&
334 has_same_uncharge_info(prg, rg)) {
338 put_uncharge_info(rg);
344 nrg = list_next_entry(rg, link);
345 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
346 has_same_uncharge_info(nrg, rg)) {
347 nrg->from = rg->from;
350 put_uncharge_info(rg);
356 hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
357 long to, struct hstate *h, struct hugetlb_cgroup *cg,
358 long *regions_needed)
360 struct file_region *nrg;
362 if (!regions_needed) {
363 nrg = get_file_region_entry_from_cache(map, from, to);
364 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
365 list_add(&nrg->link, rg->link.prev);
366 coalesce_file_region(map, nrg);
368 *regions_needed += 1;
374 * Must be called with resv->lock held.
376 * Calling this with regions_needed != NULL will count the number of pages
377 * to be added but will not modify the linked list. And regions_needed will
378 * indicate the number of file_regions needed in the cache to carry out to add
379 * the regions for this range.
381 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
382 struct hugetlb_cgroup *h_cg,
383 struct hstate *h, long *regions_needed)
386 struct list_head *head = &resv->regions;
387 long last_accounted_offset = f;
388 struct file_region *rg = NULL, *trg = NULL;
393 /* In this loop, we essentially handle an entry for the range
394 * [last_accounted_offset, rg->from), at every iteration, with some
397 list_for_each_entry_safe(rg, trg, head, link) {
398 /* Skip irrelevant regions that start before our range. */
400 /* If this region ends after the last accounted offset,
401 * then we need to update last_accounted_offset.
403 if (rg->to > last_accounted_offset)
404 last_accounted_offset = rg->to;
408 /* When we find a region that starts beyond our range, we've
414 /* Add an entry for last_accounted_offset -> rg->from, and
415 * update last_accounted_offset.
417 if (rg->from > last_accounted_offset)
418 add += hugetlb_resv_map_add(resv, rg,
419 last_accounted_offset,
423 last_accounted_offset = rg->to;
426 /* Handle the case where our range extends beyond
427 * last_accounted_offset.
429 if (last_accounted_offset < t)
430 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
431 t, h, h_cg, regions_needed);
437 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
439 static int allocate_file_region_entries(struct resv_map *resv,
441 __must_hold(&resv->lock)
443 struct list_head allocated_regions;
444 int to_allocate = 0, i = 0;
445 struct file_region *trg = NULL, *rg = NULL;
447 VM_BUG_ON(regions_needed < 0);
449 INIT_LIST_HEAD(&allocated_regions);
452 * Check for sufficient descriptors in the cache to accommodate
453 * the number of in progress add operations plus regions_needed.
455 * This is a while loop because when we drop the lock, some other call
456 * to region_add or region_del may have consumed some region_entries,
457 * so we keep looping here until we finally have enough entries for
458 * (adds_in_progress + regions_needed).
460 while (resv->region_cache_count <
461 (resv->adds_in_progress + regions_needed)) {
462 to_allocate = resv->adds_in_progress + regions_needed -
463 resv->region_cache_count;
465 /* At this point, we should have enough entries in the cache
466 * for all the existings adds_in_progress. We should only be
467 * needing to allocate for regions_needed.
469 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
471 spin_unlock(&resv->lock);
472 for (i = 0; i < to_allocate; i++) {
473 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
476 list_add(&trg->link, &allocated_regions);
479 spin_lock(&resv->lock);
481 list_splice(&allocated_regions, &resv->region_cache);
482 resv->region_cache_count += to_allocate;
488 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
496 * Add the huge page range represented by [f, t) to the reserve
497 * map. Regions will be taken from the cache to fill in this range.
498 * Sufficient regions should exist in the cache due to the previous
499 * call to region_chg with the same range, but in some cases the cache will not
500 * have sufficient entries due to races with other code doing region_add or
501 * region_del. The extra needed entries will be allocated.
503 * regions_needed is the out value provided by a previous call to region_chg.
505 * Return the number of new huge pages added to the map. This number is greater
506 * than or equal to zero. If file_region entries needed to be allocated for
507 * this operation and we were not able to allocate, it returns -ENOMEM.
508 * region_add of regions of length 1 never allocate file_regions and cannot
509 * fail; region_chg will always allocate at least 1 entry and a region_add for
510 * 1 page will only require at most 1 entry.
512 static long region_add(struct resv_map *resv, long f, long t,
513 long in_regions_needed, struct hstate *h,
514 struct hugetlb_cgroup *h_cg)
516 long add = 0, actual_regions_needed = 0;
518 spin_lock(&resv->lock);
521 /* Count how many regions are actually needed to execute this add. */
522 add_reservation_in_range(resv, f, t, NULL, NULL,
523 &actual_regions_needed);
526 * Check for sufficient descriptors in the cache to accommodate
527 * this add operation. Note that actual_regions_needed may be greater
528 * than in_regions_needed, as the resv_map may have been modified since
529 * the region_chg call. In this case, we need to make sure that we
530 * allocate extra entries, such that we have enough for all the
531 * existing adds_in_progress, plus the excess needed for this
534 if (actual_regions_needed > in_regions_needed &&
535 resv->region_cache_count <
536 resv->adds_in_progress +
537 (actual_regions_needed - in_regions_needed)) {
538 /* region_add operation of range 1 should never need to
539 * allocate file_region entries.
541 VM_BUG_ON(t - f <= 1);
543 if (allocate_file_region_entries(
544 resv, actual_regions_needed - in_regions_needed)) {
551 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
553 resv->adds_in_progress -= in_regions_needed;
555 spin_unlock(&resv->lock);
561 * Examine the existing reserve map and determine how many
562 * huge pages in the specified range [f, t) are NOT currently
563 * represented. This routine is called before a subsequent
564 * call to region_add that will actually modify the reserve
565 * map to add the specified range [f, t). region_chg does
566 * not change the number of huge pages represented by the
567 * map. A number of new file_region structures is added to the cache as a
568 * placeholder, for the subsequent region_add call to use. At least 1
569 * file_region structure is added.
571 * out_regions_needed is the number of regions added to the
572 * resv->adds_in_progress. This value needs to be provided to a follow up call
573 * to region_add or region_abort for proper accounting.
575 * Returns the number of huge pages that need to be added to the existing
576 * reservation map for the range [f, t). This number is greater or equal to
577 * zero. -ENOMEM is returned if a new file_region structure or cache entry
578 * is needed and can not be allocated.
580 static long region_chg(struct resv_map *resv, long f, long t,
581 long *out_regions_needed)
585 spin_lock(&resv->lock);
587 /* Count how many hugepages in this range are NOT represented. */
588 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
591 if (*out_regions_needed == 0)
592 *out_regions_needed = 1;
594 if (allocate_file_region_entries(resv, *out_regions_needed))
597 resv->adds_in_progress += *out_regions_needed;
599 spin_unlock(&resv->lock);
604 * Abort the in progress add operation. The adds_in_progress field
605 * of the resv_map keeps track of the operations in progress between
606 * calls to region_chg and region_add. Operations are sometimes
607 * aborted after the call to region_chg. In such cases, region_abort
608 * is called to decrement the adds_in_progress counter. regions_needed
609 * is the value returned by the region_chg call, it is used to decrement
610 * the adds_in_progress counter.
612 * NOTE: The range arguments [f, t) are not needed or used in this
613 * routine. They are kept to make reading the calling code easier as
614 * arguments will match the associated region_chg call.
616 static void region_abort(struct resv_map *resv, long f, long t,
619 spin_lock(&resv->lock);
620 VM_BUG_ON(!resv->region_cache_count);
621 resv->adds_in_progress -= regions_needed;
622 spin_unlock(&resv->lock);
626 * Delete the specified range [f, t) from the reserve map. If the
627 * t parameter is LONG_MAX, this indicates that ALL regions after f
628 * should be deleted. Locate the regions which intersect [f, t)
629 * and either trim, delete or split the existing regions.
631 * Returns the number of huge pages deleted from the reserve map.
632 * In the normal case, the return value is zero or more. In the
633 * case where a region must be split, a new region descriptor must
634 * be allocated. If the allocation fails, -ENOMEM will be returned.
635 * NOTE: If the parameter t == LONG_MAX, then we will never split
636 * a region and possibly return -ENOMEM. Callers specifying
637 * t == LONG_MAX do not need to check for -ENOMEM error.
639 static long region_del(struct resv_map *resv, long f, long t)
641 struct list_head *head = &resv->regions;
642 struct file_region *rg, *trg;
643 struct file_region *nrg = NULL;
647 spin_lock(&resv->lock);
648 list_for_each_entry_safe(rg, trg, head, link) {
650 * Skip regions before the range to be deleted. file_region
651 * ranges are normally of the form [from, to). However, there
652 * may be a "placeholder" entry in the map which is of the form
653 * (from, to) with from == to. Check for placeholder entries
654 * at the beginning of the range to be deleted.
656 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
662 if (f > rg->from && t < rg->to) { /* Must split region */
664 * Check for an entry in the cache before dropping
665 * lock and attempting allocation.
668 resv->region_cache_count > resv->adds_in_progress) {
669 nrg = list_first_entry(&resv->region_cache,
672 list_del(&nrg->link);
673 resv->region_cache_count--;
677 spin_unlock(&resv->lock);
678 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
685 hugetlb_cgroup_uncharge_file_region(
686 resv, rg, t - f, false);
688 /* New entry for end of split region */
692 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
694 INIT_LIST_HEAD(&nrg->link);
696 /* Original entry is trimmed */
699 list_add(&nrg->link, &rg->link);
704 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
705 del += rg->to - rg->from;
706 hugetlb_cgroup_uncharge_file_region(resv, rg,
707 rg->to - rg->from, true);
713 if (f <= rg->from) { /* Trim beginning of region */
714 hugetlb_cgroup_uncharge_file_region(resv, rg,
715 t - rg->from, false);
719 } else { /* Trim end of region */
720 hugetlb_cgroup_uncharge_file_region(resv, rg,
728 spin_unlock(&resv->lock);
734 * A rare out of memory error was encountered which prevented removal of
735 * the reserve map region for a page. The huge page itself was free'ed
736 * and removed from the page cache. This routine will adjust the subpool
737 * usage count, and the global reserve count if needed. By incrementing
738 * these counts, the reserve map entry which could not be deleted will
739 * appear as a "reserved" entry instead of simply dangling with incorrect
742 void hugetlb_fix_reserve_counts(struct inode *inode)
744 struct hugepage_subpool *spool = subpool_inode(inode);
747 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
749 struct hstate *h = hstate_inode(inode);
751 hugetlb_acct_memory(h, 1);
756 * Count and return the number of huge pages in the reserve map
757 * that intersect with the range [f, t).
759 static long region_count(struct resv_map *resv, long f, long t)
761 struct list_head *head = &resv->regions;
762 struct file_region *rg;
765 spin_lock(&resv->lock);
766 /* Locate each segment we overlap with, and count that overlap. */
767 list_for_each_entry(rg, head, link) {
776 seg_from = max(rg->from, f);
777 seg_to = min(rg->to, t);
779 chg += seg_to - seg_from;
781 spin_unlock(&resv->lock);
787 * Convert the address within this vma to the page offset within
788 * the mapping, in pagecache page units; huge pages here.
790 static pgoff_t vma_hugecache_offset(struct hstate *h,
791 struct vm_area_struct *vma, unsigned long address)
793 return ((address - vma->vm_start) >> huge_page_shift(h)) +
794 (vma->vm_pgoff >> huge_page_order(h));
797 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
798 unsigned long address)
800 return vma_hugecache_offset(hstate_vma(vma), vma, address);
802 EXPORT_SYMBOL_GPL(linear_hugepage_index);
805 * Return the size of the pages allocated when backing a VMA. In the majority
806 * cases this will be same size as used by the page table entries.
808 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
810 if (vma->vm_ops && vma->vm_ops->pagesize)
811 return vma->vm_ops->pagesize(vma);
814 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
817 * Return the page size being used by the MMU to back a VMA. In the majority
818 * of cases, the page size used by the kernel matches the MMU size. On
819 * architectures where it differs, an architecture-specific 'strong'
820 * version of this symbol is required.
822 __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
824 return vma_kernel_pagesize(vma);
828 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
829 * bits of the reservation map pointer, which are always clear due to
832 #define HPAGE_RESV_OWNER (1UL << 0)
833 #define HPAGE_RESV_UNMAPPED (1UL << 1)
834 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
837 * These helpers are used to track how many pages are reserved for
838 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
839 * is guaranteed to have their future faults succeed.
841 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
842 * the reserve counters are updated with the hugetlb_lock held. It is safe
843 * to reset the VMA at fork() time as it is not in use yet and there is no
844 * chance of the global counters getting corrupted as a result of the values.
846 * The private mapping reservation is represented in a subtly different
847 * manner to a shared mapping. A shared mapping has a region map associated
848 * with the underlying file, this region map represents the backing file
849 * pages which have ever had a reservation assigned which this persists even
850 * after the page is instantiated. A private mapping has a region map
851 * associated with the original mmap which is attached to all VMAs which
852 * reference it, this region map represents those offsets which have consumed
853 * reservation ie. where pages have been instantiated.
855 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
857 return (unsigned long)vma->vm_private_data;
860 static void set_vma_private_data(struct vm_area_struct *vma,
863 vma->vm_private_data = (void *)value;
867 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
868 struct hugetlb_cgroup *h_cg,
871 #ifdef CONFIG_CGROUP_HUGETLB
873 resv_map->reservation_counter = NULL;
874 resv_map->pages_per_hpage = 0;
875 resv_map->css = NULL;
877 resv_map->reservation_counter =
878 &h_cg->rsvd_hugepage[hstate_index(h)];
879 resv_map->pages_per_hpage = pages_per_huge_page(h);
880 resv_map->css = &h_cg->css;
885 struct resv_map *resv_map_alloc(void)
887 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
888 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
890 if (!resv_map || !rg) {
896 kref_init(&resv_map->refs);
897 spin_lock_init(&resv_map->lock);
898 INIT_LIST_HEAD(&resv_map->regions);
900 resv_map->adds_in_progress = 0;
902 * Initialize these to 0. On shared mappings, 0's here indicate these
903 * fields don't do cgroup accounting. On private mappings, these will be
904 * re-initialized to the proper values, to indicate that hugetlb cgroup
905 * reservations are to be un-charged from here.
907 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
909 INIT_LIST_HEAD(&resv_map->region_cache);
910 list_add(&rg->link, &resv_map->region_cache);
911 resv_map->region_cache_count = 1;
916 void resv_map_release(struct kref *ref)
918 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
919 struct list_head *head = &resv_map->region_cache;
920 struct file_region *rg, *trg;
922 /* Clear out any active regions before we release the map. */
923 region_del(resv_map, 0, LONG_MAX);
925 /* ... and any entries left in the cache */
926 list_for_each_entry_safe(rg, trg, head, link) {
931 VM_BUG_ON(resv_map->adds_in_progress);
936 static inline struct resv_map *inode_resv_map(struct inode *inode)
939 * At inode evict time, i_mapping may not point to the original
940 * address space within the inode. This original address space
941 * contains the pointer to the resv_map. So, always use the
942 * address space embedded within the inode.
943 * The VERY common case is inode->mapping == &inode->i_data but,
944 * this may not be true for device special inodes.
946 return (struct resv_map *)(&inode->i_data)->private_data;
949 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
951 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
952 if (vma->vm_flags & VM_MAYSHARE) {
953 struct address_space *mapping = vma->vm_file->f_mapping;
954 struct inode *inode = mapping->host;
956 return inode_resv_map(inode);
959 return (struct resv_map *)(get_vma_private_data(vma) &
964 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
966 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
967 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
969 set_vma_private_data(vma, (get_vma_private_data(vma) &
970 HPAGE_RESV_MASK) | (unsigned long)map);
973 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
975 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
976 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
978 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
981 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
983 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
985 return (get_vma_private_data(vma) & flag) != 0;
988 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
989 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
991 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
992 if (!(vma->vm_flags & VM_MAYSHARE))
993 vma->vm_private_data = (void *)0;
996 /* Returns true if the VMA has associated reserve pages */
997 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
999 if (vma->vm_flags & VM_NORESERVE) {
1001 * This address is already reserved by other process(chg == 0),
1002 * so, we should decrement reserved count. Without decrementing,
1003 * reserve count remains after releasing inode, because this
1004 * allocated page will go into page cache and is regarded as
1005 * coming from reserved pool in releasing step. Currently, we
1006 * don't have any other solution to deal with this situation
1007 * properly, so add work-around here.
1009 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1015 /* Shared mappings always use reserves */
1016 if (vma->vm_flags & VM_MAYSHARE) {
1018 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1019 * be a region map for all pages. The only situation where
1020 * there is no region map is if a hole was punched via
1021 * fallocate. In this case, there really are no reserves to
1022 * use. This situation is indicated if chg != 0.
1031 * Only the process that called mmap() has reserves for
1034 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1036 * Like the shared case above, a hole punch or truncate
1037 * could have been performed on the private mapping.
1038 * Examine the value of chg to determine if reserves
1039 * actually exist or were previously consumed.
1040 * Very Subtle - The value of chg comes from a previous
1041 * call to vma_needs_reserves(). The reserve map for
1042 * private mappings has different (opposite) semantics
1043 * than that of shared mappings. vma_needs_reserves()
1044 * has already taken this difference in semantics into
1045 * account. Therefore, the meaning of chg is the same
1046 * as in the shared case above. Code could easily be
1047 * combined, but keeping it separate draws attention to
1048 * subtle differences.
1059 static void enqueue_huge_page(struct hstate *h, struct page *page)
1061 int nid = page_to_nid(page);
1062 list_move(&page->lru, &h->hugepage_freelists[nid]);
1063 h->free_huge_pages++;
1064 h->free_huge_pages_node[nid]++;
1065 SetHPageFreed(page);
1068 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1071 bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
1073 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1074 if (nocma && is_migrate_cma_page(page))
1077 if (PageHWPoison(page))
1080 list_move(&page->lru, &h->hugepage_activelist);
1081 set_page_refcounted(page);
1082 ClearHPageFreed(page);
1083 h->free_huge_pages--;
1084 h->free_huge_pages_node[nid]--;
1091 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1094 unsigned int cpuset_mems_cookie;
1095 struct zonelist *zonelist;
1098 int node = NUMA_NO_NODE;
1100 zonelist = node_zonelist(nid, gfp_mask);
1103 cpuset_mems_cookie = read_mems_allowed_begin();
1104 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1107 if (!cpuset_zone_allowed(zone, gfp_mask))
1110 * no need to ask again on the same node. Pool is node rather than
1113 if (zone_to_nid(zone) == node)
1115 node = zone_to_nid(zone);
1117 page = dequeue_huge_page_node_exact(h, node);
1121 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1127 static struct page *dequeue_huge_page_vma(struct hstate *h,
1128 struct vm_area_struct *vma,
1129 unsigned long address, int avoid_reserve,
1133 struct mempolicy *mpol;
1135 nodemask_t *nodemask;
1139 * A child process with MAP_PRIVATE mappings created by their parent
1140 * have no page reserves. This check ensures that reservations are
1141 * not "stolen". The child may still get SIGKILLed
1143 if (!vma_has_reserves(vma, chg) &&
1144 h->free_huge_pages - h->resv_huge_pages == 0)
1147 /* If reserves cannot be used, ensure enough pages are in the pool */
1148 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1151 gfp_mask = htlb_alloc_mask(h);
1152 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1153 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1154 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1155 SetHPageRestoreReserve(page);
1156 h->resv_huge_pages--;
1159 mpol_cond_put(mpol);
1167 * common helper functions for hstate_next_node_to_{alloc|free}.
1168 * We may have allocated or freed a huge page based on a different
1169 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1170 * be outside of *nodes_allowed. Ensure that we use an allowed
1171 * node for alloc or free.
1173 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1175 nid = next_node_in(nid, *nodes_allowed);
1176 VM_BUG_ON(nid >= MAX_NUMNODES);
1181 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1183 if (!node_isset(nid, *nodes_allowed))
1184 nid = next_node_allowed(nid, nodes_allowed);
1189 * returns the previously saved node ["this node"] from which to
1190 * allocate a persistent huge page for the pool and advance the
1191 * next node from which to allocate, handling wrap at end of node
1194 static int hstate_next_node_to_alloc(struct hstate *h,
1195 nodemask_t *nodes_allowed)
1199 VM_BUG_ON(!nodes_allowed);
1201 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1202 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1208 * helper for free_pool_huge_page() - return the previously saved
1209 * node ["this node"] from which to free a huge page. Advance the
1210 * next node id whether or not we find a free huge page to free so
1211 * that the next attempt to free addresses the next node.
1213 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1217 VM_BUG_ON(!nodes_allowed);
1219 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1220 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1225 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1226 for (nr_nodes = nodes_weight(*mask); \
1228 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1231 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1232 for (nr_nodes = nodes_weight(*mask); \
1234 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1237 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1238 static void destroy_compound_gigantic_page(struct page *page,
1242 int nr_pages = 1 << order;
1243 struct page *p = page + 1;
1245 atomic_set(compound_mapcount_ptr(page), 0);
1246 atomic_set(compound_pincount_ptr(page), 0);
1248 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1249 clear_compound_head(p);
1250 set_page_refcounted(p);
1253 set_compound_order(page, 0);
1254 page[1].compound_nr = 0;
1255 __ClearPageHead(page);
1258 static void free_gigantic_page(struct page *page, unsigned int order)
1261 * If the page isn't allocated using the cma allocator,
1262 * cma_release() returns false.
1265 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1269 free_contig_range(page_to_pfn(page), 1 << order);
1272 #ifdef CONFIG_CONTIG_ALLOC
1273 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1274 int nid, nodemask_t *nodemask)
1276 unsigned long nr_pages = 1UL << huge_page_order(h);
1277 if (nid == NUMA_NO_NODE)
1278 nid = numa_mem_id();
1285 if (hugetlb_cma[nid]) {
1286 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1287 huge_page_order(h), true);
1292 if (!(gfp_mask & __GFP_THISNODE)) {
1293 for_each_node_mask(node, *nodemask) {
1294 if (node == nid || !hugetlb_cma[node])
1297 page = cma_alloc(hugetlb_cma[node], nr_pages,
1298 huge_page_order(h), true);
1306 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1309 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1310 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1311 #else /* !CONFIG_CONTIG_ALLOC */
1312 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1313 int nid, nodemask_t *nodemask)
1317 #endif /* CONFIG_CONTIG_ALLOC */
1319 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1320 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1321 int nid, nodemask_t *nodemask)
1325 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1326 static inline void destroy_compound_gigantic_page(struct page *page,
1327 unsigned int order) { }
1330 static void update_and_free_page(struct hstate *h, struct page *page)
1333 struct page *subpage = page;
1335 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1339 h->nr_huge_pages_node[page_to_nid(page)]--;
1340 for (i = 0; i < pages_per_huge_page(h);
1341 i++, subpage = mem_map_next(subpage, page, i)) {
1342 subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1343 1 << PG_referenced | 1 << PG_dirty |
1344 1 << PG_active | 1 << PG_private |
1347 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1348 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1349 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1350 set_page_refcounted(page);
1351 if (hstate_is_gigantic(h)) {
1353 * Temporarily drop the hugetlb_lock, because
1354 * we might block in free_gigantic_page().
1356 spin_unlock(&hugetlb_lock);
1357 destroy_compound_gigantic_page(page, huge_page_order(h));
1358 free_gigantic_page(page, huge_page_order(h));
1359 spin_lock(&hugetlb_lock);
1361 __free_pages(page, huge_page_order(h));
1365 struct hstate *size_to_hstate(unsigned long size)
1369 for_each_hstate(h) {
1370 if (huge_page_size(h) == size)
1376 static void __free_huge_page(struct page *page)
1379 * Can't pass hstate in here because it is called from the
1380 * compound page destructor.
1382 struct hstate *h = page_hstate(page);
1383 int nid = page_to_nid(page);
1384 struct hugepage_subpool *spool = hugetlb_page_subpool(page);
1385 bool restore_reserve;
1387 VM_BUG_ON_PAGE(page_count(page), page);
1388 VM_BUG_ON_PAGE(page_mapcount(page), page);
1390 hugetlb_set_page_subpool(page, NULL);
1391 page->mapping = NULL;
1392 restore_reserve = HPageRestoreReserve(page);
1393 ClearHPageRestoreReserve(page);
1396 * If HPageRestoreReserve was set on page, page allocation consumed a
1397 * reservation. If the page was associated with a subpool, there
1398 * would have been a page reserved in the subpool before allocation
1399 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1400 * reservation, do not call hugepage_subpool_put_pages() as this will
1401 * remove the reserved page from the subpool.
1403 if (!restore_reserve) {
1405 * A return code of zero implies that the subpool will be
1406 * under its minimum size if the reservation is not restored
1407 * after page is free. Therefore, force restore_reserve
1410 if (hugepage_subpool_put_pages(spool, 1) == 0)
1411 restore_reserve = true;
1414 spin_lock(&hugetlb_lock);
1415 ClearHPageMigratable(page);
1416 hugetlb_cgroup_uncharge_page(hstate_index(h),
1417 pages_per_huge_page(h), page);
1418 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1419 pages_per_huge_page(h), page);
1420 if (restore_reserve)
1421 h->resv_huge_pages++;
1423 if (HPageTemporary(page)) {
1424 list_del(&page->lru);
1425 ClearHPageTemporary(page);
1426 update_and_free_page(h, page);
1427 } else if (h->surplus_huge_pages_node[nid]) {
1428 /* remove the page from active list */
1429 list_del(&page->lru);
1430 update_and_free_page(h, page);
1431 h->surplus_huge_pages--;
1432 h->surplus_huge_pages_node[nid]--;
1434 arch_clear_hugepage_flags(page);
1435 enqueue_huge_page(h, page);
1437 spin_unlock(&hugetlb_lock);
1441 * As free_huge_page() can be called from a non-task context, we have
1442 * to defer the actual freeing in a workqueue to prevent potential
1443 * hugetlb_lock deadlock.
1445 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1446 * be freed and frees them one-by-one. As the page->mapping pointer is
1447 * going to be cleared in __free_huge_page() anyway, it is reused as the
1448 * llist_node structure of a lockless linked list of huge pages to be freed.
1450 static LLIST_HEAD(hpage_freelist);
1452 static void free_hpage_workfn(struct work_struct *work)
1454 struct llist_node *node;
1457 node = llist_del_all(&hpage_freelist);
1460 page = container_of((struct address_space **)node,
1461 struct page, mapping);
1463 __free_huge_page(page);
1466 static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1468 void free_huge_page(struct page *page)
1471 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1475 * Only call schedule_work() if hpage_freelist is previously
1476 * empty. Otherwise, schedule_work() had been called but the
1477 * workfn hasn't retrieved the list yet.
1479 if (llist_add((struct llist_node *)&page->mapping,
1481 schedule_work(&free_hpage_work);
1485 __free_huge_page(page);
1488 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1490 INIT_LIST_HEAD(&page->lru);
1491 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1492 hugetlb_set_page_subpool(page, NULL);
1493 set_hugetlb_cgroup(page, NULL);
1494 set_hugetlb_cgroup_rsvd(page, NULL);
1495 spin_lock(&hugetlb_lock);
1497 h->nr_huge_pages_node[nid]++;
1498 ClearHPageFreed(page);
1499 spin_unlock(&hugetlb_lock);
1502 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1505 int nr_pages = 1 << order;
1506 struct page *p = page + 1;
1508 /* we rely on prep_new_huge_page to set the destructor */
1509 set_compound_order(page, order);
1510 __ClearPageReserved(page);
1511 __SetPageHead(page);
1512 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1514 * For gigantic hugepages allocated through bootmem at
1515 * boot, it's safer to be consistent with the not-gigantic
1516 * hugepages and clear the PG_reserved bit from all tail pages
1517 * too. Otherwise drivers using get_user_pages() to access tail
1518 * pages may get the reference counting wrong if they see
1519 * PG_reserved set on a tail page (despite the head page not
1520 * having PG_reserved set). Enforcing this consistency between
1521 * head and tail pages allows drivers to optimize away a check
1522 * on the head page when they need know if put_page() is needed
1523 * after get_user_pages().
1525 __ClearPageReserved(p);
1526 set_page_count(p, 0);
1527 set_compound_head(p, page);
1529 atomic_set(compound_mapcount_ptr(page), -1);
1530 atomic_set(compound_pincount_ptr(page), 0);
1534 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1535 * transparent huge pages. See the PageTransHuge() documentation for more
1538 int PageHuge(struct page *page)
1540 if (!PageCompound(page))
1543 page = compound_head(page);
1544 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1546 EXPORT_SYMBOL_GPL(PageHuge);
1549 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1550 * normal or transparent huge pages.
1552 int PageHeadHuge(struct page *page_head)
1554 if (!PageHead(page_head))
1557 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1561 * Find and lock address space (mapping) in write mode.
1563 * Upon entry, the page is locked which means that page_mapping() is
1564 * stable. Due to locking order, we can only trylock_write. If we can
1565 * not get the lock, simply return NULL to caller.
1567 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1569 struct address_space *mapping = page_mapping(hpage);
1574 if (i_mmap_trylock_write(mapping))
1580 pgoff_t __basepage_index(struct page *page)
1582 struct page *page_head = compound_head(page);
1583 pgoff_t index = page_index(page_head);
1584 unsigned long compound_idx;
1586 if (!PageHuge(page_head))
1587 return page_index(page);
1589 if (compound_order(page_head) >= MAX_ORDER)
1590 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1592 compound_idx = page - page_head;
1594 return (index << compound_order(page_head)) + compound_idx;
1597 static struct page *alloc_buddy_huge_page(struct hstate *h,
1598 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1599 nodemask_t *node_alloc_noretry)
1601 int order = huge_page_order(h);
1603 bool alloc_try_hard = true;
1606 * By default we always try hard to allocate the page with
1607 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1608 * a loop (to adjust global huge page counts) and previous allocation
1609 * failed, do not continue to try hard on the same node. Use the
1610 * node_alloc_noretry bitmap to manage this state information.
1612 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1613 alloc_try_hard = false;
1614 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1616 gfp_mask |= __GFP_RETRY_MAYFAIL;
1617 if (nid == NUMA_NO_NODE)
1618 nid = numa_mem_id();
1619 page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
1621 __count_vm_event(HTLB_BUDDY_PGALLOC);
1623 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1626 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1627 * indicates an overall state change. Clear bit so that we resume
1628 * normal 'try hard' allocations.
1630 if (node_alloc_noretry && page && !alloc_try_hard)
1631 node_clear(nid, *node_alloc_noretry);
1634 * If we tried hard to get a page but failed, set bit so that
1635 * subsequent attempts will not try as hard until there is an
1636 * overall state change.
1638 if (node_alloc_noretry && !page && alloc_try_hard)
1639 node_set(nid, *node_alloc_noretry);
1645 * Common helper to allocate a fresh hugetlb page. All specific allocators
1646 * should use this function to get new hugetlb pages
1648 static struct page *alloc_fresh_huge_page(struct hstate *h,
1649 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1650 nodemask_t *node_alloc_noretry)
1654 if (hstate_is_gigantic(h))
1655 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1657 page = alloc_buddy_huge_page(h, gfp_mask,
1658 nid, nmask, node_alloc_noretry);
1662 if (hstate_is_gigantic(h))
1663 prep_compound_gigantic_page(page, huge_page_order(h));
1664 prep_new_huge_page(h, page, page_to_nid(page));
1670 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1673 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1674 nodemask_t *node_alloc_noretry)
1678 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1680 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1681 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1682 node_alloc_noretry);
1690 put_page(page); /* free it into the hugepage allocator */
1696 * Free huge page from pool from next node to free.
1697 * Attempt to keep persistent huge pages more or less
1698 * balanced over allowed nodes.
1699 * Called with hugetlb_lock locked.
1701 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1707 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1709 * If we're returning unused surplus pages, only examine
1710 * nodes with surplus pages.
1712 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1713 !list_empty(&h->hugepage_freelists[node])) {
1715 list_entry(h->hugepage_freelists[node].next,
1717 list_del(&page->lru);
1718 h->free_huge_pages--;
1719 h->free_huge_pages_node[node]--;
1721 h->surplus_huge_pages--;
1722 h->surplus_huge_pages_node[node]--;
1724 update_and_free_page(h, page);
1734 * Dissolve a given free hugepage into free buddy pages. This function does
1735 * nothing for in-use hugepages and non-hugepages.
1736 * This function returns values like below:
1738 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1739 * (allocated or reserved.)
1740 * 0: successfully dissolved free hugepages or the page is not a
1741 * hugepage (considered as already dissolved)
1743 int dissolve_free_huge_page(struct page *page)
1748 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1749 if (!PageHuge(page))
1752 spin_lock(&hugetlb_lock);
1753 if (!PageHuge(page)) {
1758 if (!page_count(page)) {
1759 struct page *head = compound_head(page);
1760 struct hstate *h = page_hstate(head);
1761 int nid = page_to_nid(head);
1762 if (h->free_huge_pages - h->resv_huge_pages == 0)
1766 * We should make sure that the page is already on the free list
1767 * when it is dissolved.
1769 if (unlikely(!HPageFreed(head))) {
1770 spin_unlock(&hugetlb_lock);
1774 * Theoretically, we should return -EBUSY when we
1775 * encounter this race. In fact, we have a chance
1776 * to successfully dissolve the page if we do a
1777 * retry. Because the race window is quite small.
1778 * If we seize this opportunity, it is an optimization
1779 * for increasing the success rate of dissolving page.
1785 * Move PageHWPoison flag from head page to the raw error page,
1786 * which makes any subpages rather than the error page reusable.
1788 if (PageHWPoison(head) && page != head) {
1789 SetPageHWPoison(page);
1790 ClearPageHWPoison(head);
1792 list_del(&head->lru);
1793 h->free_huge_pages--;
1794 h->free_huge_pages_node[nid]--;
1795 h->max_huge_pages--;
1796 update_and_free_page(h, head);
1800 spin_unlock(&hugetlb_lock);
1805 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1806 * make specified memory blocks removable from the system.
1807 * Note that this will dissolve a free gigantic hugepage completely, if any
1808 * part of it lies within the given range.
1809 * Also note that if dissolve_free_huge_page() returns with an error, all
1810 * free hugepages that were dissolved before that error are lost.
1812 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1818 if (!hugepages_supported())
1821 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1822 page = pfn_to_page(pfn);
1823 rc = dissolve_free_huge_page(page);
1832 * Allocates a fresh surplus page from the page allocator.
1834 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1835 int nid, nodemask_t *nmask)
1837 struct page *page = NULL;
1839 if (hstate_is_gigantic(h))
1842 spin_lock(&hugetlb_lock);
1843 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1845 spin_unlock(&hugetlb_lock);
1847 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1851 spin_lock(&hugetlb_lock);
1853 * We could have raced with the pool size change.
1854 * Double check that and simply deallocate the new page
1855 * if we would end up overcommiting the surpluses. Abuse
1856 * temporary page to workaround the nasty free_huge_page
1859 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1860 SetHPageTemporary(page);
1861 spin_unlock(&hugetlb_lock);
1865 h->surplus_huge_pages++;
1866 h->surplus_huge_pages_node[page_to_nid(page)]++;
1870 spin_unlock(&hugetlb_lock);
1875 static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1876 int nid, nodemask_t *nmask)
1880 if (hstate_is_gigantic(h))
1883 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1888 * We do not account these pages as surplus because they are only
1889 * temporary and will be released properly on the last reference
1891 SetHPageTemporary(page);
1897 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1900 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1901 struct vm_area_struct *vma, unsigned long addr)
1904 struct mempolicy *mpol;
1905 gfp_t gfp_mask = htlb_alloc_mask(h);
1907 nodemask_t *nodemask;
1909 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1910 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1911 mpol_cond_put(mpol);
1916 /* page migration callback function */
1917 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1918 nodemask_t *nmask, gfp_t gfp_mask)
1920 spin_lock(&hugetlb_lock);
1921 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1924 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1926 spin_unlock(&hugetlb_lock);
1930 spin_unlock(&hugetlb_lock);
1932 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1935 /* mempolicy aware migration callback */
1936 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
1937 unsigned long address)
1939 struct mempolicy *mpol;
1940 nodemask_t *nodemask;
1945 gfp_mask = htlb_alloc_mask(h);
1946 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1947 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
1948 mpol_cond_put(mpol);
1954 * Increase the hugetlb pool such that it can accommodate a reservation
1957 static int gather_surplus_pages(struct hstate *h, long delta)
1958 __must_hold(&hugetlb_lock)
1960 struct list_head surplus_list;
1961 struct page *page, *tmp;
1964 long needed, allocated;
1965 bool alloc_ok = true;
1967 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1969 h->resv_huge_pages += delta;
1974 INIT_LIST_HEAD(&surplus_list);
1978 spin_unlock(&hugetlb_lock);
1979 for (i = 0; i < needed; i++) {
1980 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1981 NUMA_NO_NODE, NULL);
1986 list_add(&page->lru, &surplus_list);
1992 * After retaking hugetlb_lock, we need to recalculate 'needed'
1993 * because either resv_huge_pages or free_huge_pages may have changed.
1995 spin_lock(&hugetlb_lock);
1996 needed = (h->resv_huge_pages + delta) -
1997 (h->free_huge_pages + allocated);
2002 * We were not able to allocate enough pages to
2003 * satisfy the entire reservation so we free what
2004 * we've allocated so far.
2009 * The surplus_list now contains _at_least_ the number of extra pages
2010 * needed to accommodate the reservation. Add the appropriate number
2011 * of pages to the hugetlb pool and free the extras back to the buddy
2012 * allocator. Commit the entire reservation here to prevent another
2013 * process from stealing the pages as they are added to the pool but
2014 * before they are reserved.
2016 needed += allocated;
2017 h->resv_huge_pages += delta;
2020 /* Free the needed pages to the hugetlb pool */
2021 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2027 * This page is now managed by the hugetlb allocator and has
2028 * no users -- drop the buddy allocator's reference.
2030 zeroed = put_page_testzero(page);
2031 VM_BUG_ON_PAGE(!zeroed, page);
2032 enqueue_huge_page(h, page);
2035 spin_unlock(&hugetlb_lock);
2037 /* Free unnecessary surplus pages to the buddy allocator */
2038 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2040 spin_lock(&hugetlb_lock);
2046 * This routine has two main purposes:
2047 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2048 * in unused_resv_pages. This corresponds to the prior adjustments made
2049 * to the associated reservation map.
2050 * 2) Free any unused surplus pages that may have been allocated to satisfy
2051 * the reservation. As many as unused_resv_pages may be freed.
2053 * Called with hugetlb_lock held. However, the lock could be dropped (and
2054 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2055 * we must make sure nobody else can claim pages we are in the process of
2056 * freeing. Do this by ensuring resv_huge_page always is greater than the
2057 * number of huge pages we plan to free when dropping the lock.
2059 static void return_unused_surplus_pages(struct hstate *h,
2060 unsigned long unused_resv_pages)
2062 unsigned long nr_pages;
2064 /* Cannot return gigantic pages currently */
2065 if (hstate_is_gigantic(h))
2069 * Part (or even all) of the reservation could have been backed
2070 * by pre-allocated pages. Only free surplus pages.
2072 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2075 * We want to release as many surplus pages as possible, spread
2076 * evenly across all nodes with memory. Iterate across these nodes
2077 * until we can no longer free unreserved surplus pages. This occurs
2078 * when the nodes with surplus pages have no free pages.
2079 * free_pool_huge_page() will balance the freed pages across the
2080 * on-line nodes with memory and will handle the hstate accounting.
2082 * Note that we decrement resv_huge_pages as we free the pages. If
2083 * we drop the lock, resv_huge_pages will still be sufficiently large
2084 * to cover subsequent pages we may free.
2086 while (nr_pages--) {
2087 h->resv_huge_pages--;
2088 unused_resv_pages--;
2089 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2091 cond_resched_lock(&hugetlb_lock);
2095 /* Fully uncommit the reservation */
2096 h->resv_huge_pages -= unused_resv_pages;
2101 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2102 * are used by the huge page allocation routines to manage reservations.
2104 * vma_needs_reservation is called to determine if the huge page at addr
2105 * within the vma has an associated reservation. If a reservation is
2106 * needed, the value 1 is returned. The caller is then responsible for
2107 * managing the global reservation and subpool usage counts. After
2108 * the huge page has been allocated, vma_commit_reservation is called
2109 * to add the page to the reservation map. If the page allocation fails,
2110 * the reservation must be ended instead of committed. vma_end_reservation
2111 * is called in such cases.
2113 * In the normal case, vma_commit_reservation returns the same value
2114 * as the preceding vma_needs_reservation call. The only time this
2115 * is not the case is if a reserve map was changed between calls. It
2116 * is the responsibility of the caller to notice the difference and
2117 * take appropriate action.
2119 * vma_add_reservation is used in error paths where a reservation must
2120 * be restored when a newly allocated huge page must be freed. It is
2121 * to be called after calling vma_needs_reservation to determine if a
2122 * reservation exists.
2124 enum vma_resv_mode {
2130 static long __vma_reservation_common(struct hstate *h,
2131 struct vm_area_struct *vma, unsigned long addr,
2132 enum vma_resv_mode mode)
2134 struct resv_map *resv;
2137 long dummy_out_regions_needed;
2139 resv = vma_resv_map(vma);
2143 idx = vma_hugecache_offset(h, vma, addr);
2145 case VMA_NEEDS_RESV:
2146 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2147 /* We assume that vma_reservation_* routines always operate on
2148 * 1 page, and that adding to resv map a 1 page entry can only
2149 * ever require 1 region.
2151 VM_BUG_ON(dummy_out_regions_needed != 1);
2153 case VMA_COMMIT_RESV:
2154 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2155 /* region_add calls of range 1 should never fail. */
2159 region_abort(resv, idx, idx + 1, 1);
2163 if (vma->vm_flags & VM_MAYSHARE) {
2164 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2165 /* region_add calls of range 1 should never fail. */
2168 region_abort(resv, idx, idx + 1, 1);
2169 ret = region_del(resv, idx, idx + 1);
2176 if (vma->vm_flags & VM_MAYSHARE)
2178 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
2180 * In most cases, reserves always exist for private mappings.
2181 * However, a file associated with mapping could have been
2182 * hole punched or truncated after reserves were consumed.
2183 * As subsequent fault on such a range will not use reserves.
2184 * Subtle - The reserve map for private mappings has the
2185 * opposite meaning than that of shared mappings. If NO
2186 * entry is in the reserve map, it means a reservation exists.
2187 * If an entry exists in the reserve map, it means the
2188 * reservation has already been consumed. As a result, the
2189 * return value of this routine is the opposite of the
2190 * value returned from reserve map manipulation routines above.
2198 return ret < 0 ? ret : 0;
2201 static long vma_needs_reservation(struct hstate *h,
2202 struct vm_area_struct *vma, unsigned long addr)
2204 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2207 static long vma_commit_reservation(struct hstate *h,
2208 struct vm_area_struct *vma, unsigned long addr)
2210 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2213 static void vma_end_reservation(struct hstate *h,
2214 struct vm_area_struct *vma, unsigned long addr)
2216 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2219 static long vma_add_reservation(struct hstate *h,
2220 struct vm_area_struct *vma, unsigned long addr)
2222 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2226 * This routine is called to restore a reservation on error paths. In the
2227 * specific error paths, a huge page was allocated (via alloc_huge_page)
2228 * and is about to be freed. If a reservation for the page existed,
2229 * alloc_huge_page would have consumed the reservation and set
2230 * HPageRestoreReserve in the newly allocated page. When the page is freed
2231 * via free_huge_page, the global reservation count will be incremented if
2232 * HPageRestoreReserve is set. However, free_huge_page can not adjust the
2233 * reserve map. Adjust the reserve map here to be consistent with global
2234 * reserve count adjustments to be made by free_huge_page.
2236 static void restore_reserve_on_error(struct hstate *h,
2237 struct vm_area_struct *vma, unsigned long address,
2240 if (unlikely(HPageRestoreReserve(page))) {
2241 long rc = vma_needs_reservation(h, vma, address);
2243 if (unlikely(rc < 0)) {
2245 * Rare out of memory condition in reserve map
2246 * manipulation. Clear HPageRestoreReserve so that
2247 * global reserve count will not be incremented
2248 * by free_huge_page. This will make it appear
2249 * as though the reservation for this page was
2250 * consumed. This may prevent the task from
2251 * faulting in the page at a later time. This
2252 * is better than inconsistent global huge page
2253 * accounting of reserve counts.
2255 ClearHPageRestoreReserve(page);
2257 rc = vma_add_reservation(h, vma, address);
2258 if (unlikely(rc < 0))
2260 * See above comment about rare out of
2263 ClearHPageRestoreReserve(page);
2265 vma_end_reservation(h, vma, address);
2269 struct page *alloc_huge_page(struct vm_area_struct *vma,
2270 unsigned long addr, int avoid_reserve)
2272 struct hugepage_subpool *spool = subpool_vma(vma);
2273 struct hstate *h = hstate_vma(vma);
2275 long map_chg, map_commit;
2278 struct hugetlb_cgroup *h_cg;
2279 bool deferred_reserve;
2281 idx = hstate_index(h);
2283 * Examine the region/reserve map to determine if the process
2284 * has a reservation for the page to be allocated. A return
2285 * code of zero indicates a reservation exists (no change).
2287 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2289 return ERR_PTR(-ENOMEM);
2292 * Processes that did not create the mapping will have no
2293 * reserves as indicated by the region/reserve map. Check
2294 * that the allocation will not exceed the subpool limit.
2295 * Allocations for MAP_NORESERVE mappings also need to be
2296 * checked against any subpool limit.
2298 if (map_chg || avoid_reserve) {
2299 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2301 vma_end_reservation(h, vma, addr);
2302 return ERR_PTR(-ENOSPC);
2306 * Even though there was no reservation in the region/reserve
2307 * map, there could be reservations associated with the
2308 * subpool that can be used. This would be indicated if the
2309 * return value of hugepage_subpool_get_pages() is zero.
2310 * However, if avoid_reserve is specified we still avoid even
2311 * the subpool reservations.
2317 /* If this allocation is not consuming a reservation, charge it now.
2319 deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
2320 if (deferred_reserve) {
2321 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2322 idx, pages_per_huge_page(h), &h_cg);
2324 goto out_subpool_put;
2327 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2329 goto out_uncharge_cgroup_reservation;
2331 spin_lock(&hugetlb_lock);
2333 * glb_chg is passed to indicate whether or not a page must be taken
2334 * from the global free pool (global change). gbl_chg == 0 indicates
2335 * a reservation exists for the allocation.
2337 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2339 spin_unlock(&hugetlb_lock);
2340 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2342 goto out_uncharge_cgroup;
2343 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2344 SetHPageRestoreReserve(page);
2345 h->resv_huge_pages--;
2347 spin_lock(&hugetlb_lock);
2348 list_add(&page->lru, &h->hugepage_activelist);
2351 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2352 /* If allocation is not consuming a reservation, also store the
2353 * hugetlb_cgroup pointer on the page.
2355 if (deferred_reserve) {
2356 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2360 spin_unlock(&hugetlb_lock);
2362 hugetlb_set_page_subpool(page, spool);
2364 map_commit = vma_commit_reservation(h, vma, addr);
2365 if (unlikely(map_chg > map_commit)) {
2367 * The page was added to the reservation map between
2368 * vma_needs_reservation and vma_commit_reservation.
2369 * This indicates a race with hugetlb_reserve_pages.
2370 * Adjust for the subpool count incremented above AND
2371 * in hugetlb_reserve_pages for the same page. Also,
2372 * the reservation count added in hugetlb_reserve_pages
2373 * no longer applies.
2377 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2378 hugetlb_acct_memory(h, -rsv_adjust);
2379 if (deferred_reserve)
2380 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2381 pages_per_huge_page(h), page);
2385 out_uncharge_cgroup:
2386 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2387 out_uncharge_cgroup_reservation:
2388 if (deferred_reserve)
2389 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2392 if (map_chg || avoid_reserve)
2393 hugepage_subpool_put_pages(spool, 1);
2394 vma_end_reservation(h, vma, addr);
2395 return ERR_PTR(-ENOSPC);
2398 int alloc_bootmem_huge_page(struct hstate *h)
2399 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2400 int __alloc_bootmem_huge_page(struct hstate *h)
2402 struct huge_bootmem_page *m;
2405 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2408 addr = memblock_alloc_try_nid_raw(
2409 huge_page_size(h), huge_page_size(h),
2410 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2413 * Use the beginning of the huge page to store the
2414 * huge_bootmem_page struct (until gather_bootmem
2415 * puts them into the mem_map).
2424 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2425 /* Put them into a private list first because mem_map is not up yet */
2426 INIT_LIST_HEAD(&m->list);
2427 list_add(&m->list, &huge_boot_pages);
2432 static void __init prep_compound_huge_page(struct page *page,
2435 if (unlikely(order > (MAX_ORDER - 1)))
2436 prep_compound_gigantic_page(page, order);
2438 prep_compound_page(page, order);
2441 /* Put bootmem huge pages into the standard lists after mem_map is up */
2442 static void __init gather_bootmem_prealloc(void)
2444 struct huge_bootmem_page *m;
2446 list_for_each_entry(m, &huge_boot_pages, list) {
2447 struct page *page = virt_to_page(m);
2448 struct hstate *h = m->hstate;
2450 WARN_ON(page_count(page) != 1);
2451 prep_compound_huge_page(page, huge_page_order(h));
2452 WARN_ON(PageReserved(page));
2453 prep_new_huge_page(h, page, page_to_nid(page));
2454 put_page(page); /* free it into the hugepage allocator */
2457 * If we had gigantic hugepages allocated at boot time, we need
2458 * to restore the 'stolen' pages to totalram_pages in order to
2459 * fix confusing memory reports from free(1) and another
2460 * side-effects, like CommitLimit going negative.
2462 if (hstate_is_gigantic(h))
2463 adjust_managed_page_count(page, pages_per_huge_page(h));
2468 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2471 nodemask_t *node_alloc_noretry;
2473 if (!hstate_is_gigantic(h)) {
2475 * Bit mask controlling how hard we retry per-node allocations.
2476 * Ignore errors as lower level routines can deal with
2477 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2478 * time, we are likely in bigger trouble.
2480 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2483 /* allocations done at boot time */
2484 node_alloc_noretry = NULL;
2487 /* bit mask controlling how hard we retry per-node allocations */
2488 if (node_alloc_noretry)
2489 nodes_clear(*node_alloc_noretry);
2491 for (i = 0; i < h->max_huge_pages; ++i) {
2492 if (hstate_is_gigantic(h)) {
2493 if (hugetlb_cma_size) {
2494 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2497 if (!alloc_bootmem_huge_page(h))
2499 } else if (!alloc_pool_huge_page(h,
2500 &node_states[N_MEMORY],
2501 node_alloc_noretry))
2505 if (i < h->max_huge_pages) {
2508 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2509 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2510 h->max_huge_pages, buf, i);
2511 h->max_huge_pages = i;
2514 kfree(node_alloc_noretry);
2517 static void __init hugetlb_init_hstates(void)
2521 for_each_hstate(h) {
2522 if (minimum_order > huge_page_order(h))
2523 minimum_order = huge_page_order(h);
2525 /* oversize hugepages were init'ed in early boot */
2526 if (!hstate_is_gigantic(h))
2527 hugetlb_hstate_alloc_pages(h);
2529 VM_BUG_ON(minimum_order == UINT_MAX);
2532 static void __init report_hugepages(void)
2536 for_each_hstate(h) {
2539 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2540 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2541 buf, h->free_huge_pages);
2545 #ifdef CONFIG_HIGHMEM
2546 static void try_to_free_low(struct hstate *h, unsigned long count,
2547 nodemask_t *nodes_allowed)
2551 if (hstate_is_gigantic(h))
2554 for_each_node_mask(i, *nodes_allowed) {
2555 struct page *page, *next;
2556 struct list_head *freel = &h->hugepage_freelists[i];
2557 list_for_each_entry_safe(page, next, freel, lru) {
2558 if (count >= h->nr_huge_pages)
2560 if (PageHighMem(page))
2562 list_del(&page->lru);
2563 update_and_free_page(h, page);
2564 h->free_huge_pages--;
2565 h->free_huge_pages_node[page_to_nid(page)]--;
2570 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2571 nodemask_t *nodes_allowed)
2577 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2578 * balanced by operating on them in a round-robin fashion.
2579 * Returns 1 if an adjustment was made.
2581 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2586 VM_BUG_ON(delta != -1 && delta != 1);
2589 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2590 if (h->surplus_huge_pages_node[node])
2594 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2595 if (h->surplus_huge_pages_node[node] <
2596 h->nr_huge_pages_node[node])
2603 h->surplus_huge_pages += delta;
2604 h->surplus_huge_pages_node[node] += delta;
2608 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2609 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2610 nodemask_t *nodes_allowed)
2612 unsigned long min_count, ret;
2613 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2616 * Bit mask controlling how hard we retry per-node allocations.
2617 * If we can not allocate the bit mask, do not attempt to allocate
2618 * the requested huge pages.
2620 if (node_alloc_noretry)
2621 nodes_clear(*node_alloc_noretry);
2625 spin_lock(&hugetlb_lock);
2628 * Check for a node specific request.
2629 * Changing node specific huge page count may require a corresponding
2630 * change to the global count. In any case, the passed node mask
2631 * (nodes_allowed) will restrict alloc/free to the specified node.
2633 if (nid != NUMA_NO_NODE) {
2634 unsigned long old_count = count;
2636 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2638 * User may have specified a large count value which caused the
2639 * above calculation to overflow. In this case, they wanted
2640 * to allocate as many huge pages as possible. Set count to
2641 * largest possible value to align with their intention.
2643 if (count < old_count)
2648 * Gigantic pages runtime allocation depend on the capability for large
2649 * page range allocation.
2650 * If the system does not provide this feature, return an error when
2651 * the user tries to allocate gigantic pages but let the user free the
2652 * boottime allocated gigantic pages.
2654 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2655 if (count > persistent_huge_pages(h)) {
2656 spin_unlock(&hugetlb_lock);
2657 NODEMASK_FREE(node_alloc_noretry);
2660 /* Fall through to decrease pool */
2664 * Increase the pool size
2665 * First take pages out of surplus state. Then make up the
2666 * remaining difference by allocating fresh huge pages.
2668 * We might race with alloc_surplus_huge_page() here and be unable
2669 * to convert a surplus huge page to a normal huge page. That is
2670 * not critical, though, it just means the overall size of the
2671 * pool might be one hugepage larger than it needs to be, but
2672 * within all the constraints specified by the sysctls.
2674 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2675 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2679 while (count > persistent_huge_pages(h)) {
2681 * If this allocation races such that we no longer need the
2682 * page, free_huge_page will handle it by freeing the page
2683 * and reducing the surplus.
2685 spin_unlock(&hugetlb_lock);
2687 /* yield cpu to avoid soft lockup */
2690 ret = alloc_pool_huge_page(h, nodes_allowed,
2691 node_alloc_noretry);
2692 spin_lock(&hugetlb_lock);
2696 /* Bail for signals. Probably ctrl-c from user */
2697 if (signal_pending(current))
2702 * Decrease the pool size
2703 * First return free pages to the buddy allocator (being careful
2704 * to keep enough around to satisfy reservations). Then place
2705 * pages into surplus state as needed so the pool will shrink
2706 * to the desired size as pages become free.
2708 * By placing pages into the surplus state independent of the
2709 * overcommit value, we are allowing the surplus pool size to
2710 * exceed overcommit. There are few sane options here. Since
2711 * alloc_surplus_huge_page() is checking the global counter,
2712 * though, we'll note that we're not allowed to exceed surplus
2713 * and won't grow the pool anywhere else. Not until one of the
2714 * sysctls are changed, or the surplus pages go out of use.
2716 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2717 min_count = max(count, min_count);
2718 try_to_free_low(h, min_count, nodes_allowed);
2719 while (min_count < persistent_huge_pages(h)) {
2720 if (!free_pool_huge_page(h, nodes_allowed, 0))
2722 cond_resched_lock(&hugetlb_lock);
2724 while (count < persistent_huge_pages(h)) {
2725 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2729 h->max_huge_pages = persistent_huge_pages(h);
2730 spin_unlock(&hugetlb_lock);
2732 NODEMASK_FREE(node_alloc_noretry);
2737 #define HSTATE_ATTR_RO(_name) \
2738 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2740 #define HSTATE_ATTR(_name) \
2741 static struct kobj_attribute _name##_attr = \
2742 __ATTR(_name, 0644, _name##_show, _name##_store)
2744 static struct kobject *hugepages_kobj;
2745 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2747 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2749 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2753 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2754 if (hstate_kobjs[i] == kobj) {
2756 *nidp = NUMA_NO_NODE;
2760 return kobj_to_node_hstate(kobj, nidp);
2763 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2764 struct kobj_attribute *attr, char *buf)
2767 unsigned long nr_huge_pages;
2770 h = kobj_to_hstate(kobj, &nid);
2771 if (nid == NUMA_NO_NODE)
2772 nr_huge_pages = h->nr_huge_pages;
2774 nr_huge_pages = h->nr_huge_pages_node[nid];
2776 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
2779 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2780 struct hstate *h, int nid,
2781 unsigned long count, size_t len)
2784 nodemask_t nodes_allowed, *n_mask;
2786 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2789 if (nid == NUMA_NO_NODE) {
2791 * global hstate attribute
2793 if (!(obey_mempolicy &&
2794 init_nodemask_of_mempolicy(&nodes_allowed)))
2795 n_mask = &node_states[N_MEMORY];
2797 n_mask = &nodes_allowed;
2800 * Node specific request. count adjustment happens in
2801 * set_max_huge_pages() after acquiring hugetlb_lock.
2803 init_nodemask_of_node(&nodes_allowed, nid);
2804 n_mask = &nodes_allowed;
2807 err = set_max_huge_pages(h, count, nid, n_mask);
2809 return err ? err : len;
2812 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2813 struct kobject *kobj, const char *buf,
2817 unsigned long count;
2821 err = kstrtoul(buf, 10, &count);
2825 h = kobj_to_hstate(kobj, &nid);
2826 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2829 static ssize_t nr_hugepages_show(struct kobject *kobj,
2830 struct kobj_attribute *attr, char *buf)
2832 return nr_hugepages_show_common(kobj, attr, buf);
2835 static ssize_t nr_hugepages_store(struct kobject *kobj,
2836 struct kobj_attribute *attr, const char *buf, size_t len)
2838 return nr_hugepages_store_common(false, kobj, buf, len);
2840 HSTATE_ATTR(nr_hugepages);
2845 * hstate attribute for optionally mempolicy-based constraint on persistent
2846 * huge page alloc/free.
2848 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2849 struct kobj_attribute *attr,
2852 return nr_hugepages_show_common(kobj, attr, buf);
2855 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2856 struct kobj_attribute *attr, const char *buf, size_t len)
2858 return nr_hugepages_store_common(true, kobj, buf, len);
2860 HSTATE_ATTR(nr_hugepages_mempolicy);
2864 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2865 struct kobj_attribute *attr, char *buf)
2867 struct hstate *h = kobj_to_hstate(kobj, NULL);
2868 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
2871 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2872 struct kobj_attribute *attr, const char *buf, size_t count)
2875 unsigned long input;
2876 struct hstate *h = kobj_to_hstate(kobj, NULL);
2878 if (hstate_is_gigantic(h))
2881 err = kstrtoul(buf, 10, &input);
2885 spin_lock(&hugetlb_lock);
2886 h->nr_overcommit_huge_pages = input;
2887 spin_unlock(&hugetlb_lock);
2891 HSTATE_ATTR(nr_overcommit_hugepages);
2893 static ssize_t free_hugepages_show(struct kobject *kobj,
2894 struct kobj_attribute *attr, char *buf)
2897 unsigned long free_huge_pages;
2900 h = kobj_to_hstate(kobj, &nid);
2901 if (nid == NUMA_NO_NODE)
2902 free_huge_pages = h->free_huge_pages;
2904 free_huge_pages = h->free_huge_pages_node[nid];
2906 return sysfs_emit(buf, "%lu\n", free_huge_pages);
2908 HSTATE_ATTR_RO(free_hugepages);
2910 static ssize_t resv_hugepages_show(struct kobject *kobj,
2911 struct kobj_attribute *attr, char *buf)
2913 struct hstate *h = kobj_to_hstate(kobj, NULL);
2914 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
2916 HSTATE_ATTR_RO(resv_hugepages);
2918 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2919 struct kobj_attribute *attr, char *buf)
2922 unsigned long surplus_huge_pages;
2925 h = kobj_to_hstate(kobj, &nid);
2926 if (nid == NUMA_NO_NODE)
2927 surplus_huge_pages = h->surplus_huge_pages;
2929 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2931 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
2933 HSTATE_ATTR_RO(surplus_hugepages);
2935 static struct attribute *hstate_attrs[] = {
2936 &nr_hugepages_attr.attr,
2937 &nr_overcommit_hugepages_attr.attr,
2938 &free_hugepages_attr.attr,
2939 &resv_hugepages_attr.attr,
2940 &surplus_hugepages_attr.attr,
2942 &nr_hugepages_mempolicy_attr.attr,
2947 static const struct attribute_group hstate_attr_group = {
2948 .attrs = hstate_attrs,
2951 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2952 struct kobject **hstate_kobjs,
2953 const struct attribute_group *hstate_attr_group)
2956 int hi = hstate_index(h);
2958 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2959 if (!hstate_kobjs[hi])
2962 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2964 kobject_put(hstate_kobjs[hi]);
2965 hstate_kobjs[hi] = NULL;
2971 static void __init hugetlb_sysfs_init(void)
2976 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
2977 if (!hugepages_kobj)
2980 for_each_hstate(h) {
2981 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
2982 hstate_kobjs, &hstate_attr_group);
2984 pr_err("HugeTLB: Unable to add hstate %s", h->name);
2991 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2992 * with node devices in node_devices[] using a parallel array. The array
2993 * index of a node device or _hstate == node id.
2994 * This is here to avoid any static dependency of the node device driver, in
2995 * the base kernel, on the hugetlb module.
2997 struct node_hstate {
2998 struct kobject *hugepages_kobj;
2999 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3001 static struct node_hstate node_hstates[MAX_NUMNODES];
3004 * A subset of global hstate attributes for node devices
3006 static struct attribute *per_node_hstate_attrs[] = {
3007 &nr_hugepages_attr.attr,
3008 &free_hugepages_attr.attr,
3009 &surplus_hugepages_attr.attr,
3013 static const struct attribute_group per_node_hstate_attr_group = {
3014 .attrs = per_node_hstate_attrs,
3018 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3019 * Returns node id via non-NULL nidp.
3021 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3025 for (nid = 0; nid < nr_node_ids; nid++) {
3026 struct node_hstate *nhs = &node_hstates[nid];
3028 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3029 if (nhs->hstate_kobjs[i] == kobj) {
3041 * Unregister hstate attributes from a single node device.
3042 * No-op if no hstate attributes attached.
3044 static void hugetlb_unregister_node(struct node *node)
3047 struct node_hstate *nhs = &node_hstates[node->dev.id];
3049 if (!nhs->hugepages_kobj)
3050 return; /* no hstate attributes */
3052 for_each_hstate(h) {
3053 int idx = hstate_index(h);
3054 if (nhs->hstate_kobjs[idx]) {
3055 kobject_put(nhs->hstate_kobjs[idx]);
3056 nhs->hstate_kobjs[idx] = NULL;
3060 kobject_put(nhs->hugepages_kobj);
3061 nhs->hugepages_kobj = NULL;
3066 * Register hstate attributes for a single node device.
3067 * No-op if attributes already registered.
3069 static void hugetlb_register_node(struct node *node)
3072 struct node_hstate *nhs = &node_hstates[node->dev.id];
3075 if (nhs->hugepages_kobj)
3076 return; /* already allocated */
3078 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3080 if (!nhs->hugepages_kobj)
3083 for_each_hstate(h) {
3084 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3086 &per_node_hstate_attr_group);
3088 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3089 h->name, node->dev.id);
3090 hugetlb_unregister_node(node);
3097 * hugetlb init time: register hstate attributes for all registered node
3098 * devices of nodes that have memory. All on-line nodes should have
3099 * registered their associated device by this time.
3101 static void __init hugetlb_register_all_nodes(void)
3105 for_each_node_state(nid, N_MEMORY) {
3106 struct node *node = node_devices[nid];
3107 if (node->dev.id == nid)
3108 hugetlb_register_node(node);
3112 * Let the node device driver know we're here so it can
3113 * [un]register hstate attributes on node hotplug.
3115 register_hugetlbfs_with_node(hugetlb_register_node,
3116 hugetlb_unregister_node);
3118 #else /* !CONFIG_NUMA */
3120 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3128 static void hugetlb_register_all_nodes(void) { }
3132 static int __init hugetlb_init(void)
3136 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3139 if (!hugepages_supported()) {
3140 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3141 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3146 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3147 * architectures depend on setup being done here.
3149 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3150 if (!parsed_default_hugepagesz) {
3152 * If we did not parse a default huge page size, set
3153 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3154 * number of huge pages for this default size was implicitly
3155 * specified, set that here as well.
3156 * Note that the implicit setting will overwrite an explicit
3157 * setting. A warning will be printed in this case.
3159 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3160 if (default_hstate_max_huge_pages) {
3161 if (default_hstate.max_huge_pages) {
3164 string_get_size(huge_page_size(&default_hstate),
3165 1, STRING_UNITS_2, buf, 32);
3166 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3167 default_hstate.max_huge_pages, buf);
3168 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3169 default_hstate_max_huge_pages);
3171 default_hstate.max_huge_pages =
3172 default_hstate_max_huge_pages;
3176 hugetlb_cma_check();
3177 hugetlb_init_hstates();
3178 gather_bootmem_prealloc();
3181 hugetlb_sysfs_init();
3182 hugetlb_register_all_nodes();
3183 hugetlb_cgroup_file_init();
3186 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3188 num_fault_mutexes = 1;
3190 hugetlb_fault_mutex_table =
3191 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3193 BUG_ON(!hugetlb_fault_mutex_table);
3195 for (i = 0; i < num_fault_mutexes; i++)
3196 mutex_init(&hugetlb_fault_mutex_table[i]);
3199 subsys_initcall(hugetlb_init);
3201 /* Overwritten by architectures with more huge page sizes */
3202 bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3204 return size == HPAGE_SIZE;
3207 void __init hugetlb_add_hstate(unsigned int order)
3212 if (size_to_hstate(PAGE_SIZE << order)) {
3215 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3217 h = &hstates[hugetlb_max_hstate++];
3219 h->mask = ~(huge_page_size(h) - 1);
3220 for (i = 0; i < MAX_NUMNODES; ++i)
3221 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3222 INIT_LIST_HEAD(&h->hugepage_activelist);
3223 h->next_nid_to_alloc = first_memory_node;
3224 h->next_nid_to_free = first_memory_node;
3225 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3226 huge_page_size(h)/1024);
3232 * hugepages command line processing
3233 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3234 * specification. If not, ignore the hugepages value. hugepages can also
3235 * be the first huge page command line option in which case it implicitly
3236 * specifies the number of huge pages for the default size.
3238 static int __init hugepages_setup(char *s)
3241 static unsigned long *last_mhp;
3243 if (!parsed_valid_hugepagesz) {
3244 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3245 parsed_valid_hugepagesz = true;
3250 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3251 * yet, so this hugepages= parameter goes to the "default hstate".
3252 * Otherwise, it goes with the previously parsed hugepagesz or
3253 * default_hugepagesz.
3255 else if (!hugetlb_max_hstate)
3256 mhp = &default_hstate_max_huge_pages;
3258 mhp = &parsed_hstate->max_huge_pages;
3260 if (mhp == last_mhp) {
3261 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3265 if (sscanf(s, "%lu", mhp) <= 0)
3269 * Global state is always initialized later in hugetlb_init.
3270 * But we need to allocate >= MAX_ORDER hstates here early to still
3271 * use the bootmem allocator.
3273 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3274 hugetlb_hstate_alloc_pages(parsed_hstate);
3280 __setup("hugepages=", hugepages_setup);
3283 * hugepagesz command line processing
3284 * A specific huge page size can only be specified once with hugepagesz.
3285 * hugepagesz is followed by hugepages on the command line. The global
3286 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3287 * hugepagesz argument was valid.
3289 static int __init hugepagesz_setup(char *s)
3294 parsed_valid_hugepagesz = false;
3295 size = (unsigned long)memparse(s, NULL);
3297 if (!arch_hugetlb_valid_size(size)) {
3298 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3302 h = size_to_hstate(size);
3305 * hstate for this size already exists. This is normally
3306 * an error, but is allowed if the existing hstate is the
3307 * default hstate. More specifically, it is only allowed if
3308 * the number of huge pages for the default hstate was not
3309 * previously specified.
3311 if (!parsed_default_hugepagesz || h != &default_hstate ||
3312 default_hstate.max_huge_pages) {
3313 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3318 * No need to call hugetlb_add_hstate() as hstate already
3319 * exists. But, do set parsed_hstate so that a following
3320 * hugepages= parameter will be applied to this hstate.
3323 parsed_valid_hugepagesz = true;
3327 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3328 parsed_valid_hugepagesz = true;
3331 __setup("hugepagesz=", hugepagesz_setup);
3334 * default_hugepagesz command line input
3335 * Only one instance of default_hugepagesz allowed on command line.
3337 static int __init default_hugepagesz_setup(char *s)
3341 parsed_valid_hugepagesz = false;
3342 if (parsed_default_hugepagesz) {
3343 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3347 size = (unsigned long)memparse(s, NULL);
3349 if (!arch_hugetlb_valid_size(size)) {
3350 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3354 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3355 parsed_valid_hugepagesz = true;
3356 parsed_default_hugepagesz = true;
3357 default_hstate_idx = hstate_index(size_to_hstate(size));
3360 * The number of default huge pages (for this size) could have been
3361 * specified as the first hugetlb parameter: hugepages=X. If so,
3362 * then default_hstate_max_huge_pages is set. If the default huge
3363 * page size is gigantic (>= MAX_ORDER), then the pages must be
3364 * allocated here from bootmem allocator.
3366 if (default_hstate_max_huge_pages) {
3367 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3368 if (hstate_is_gigantic(&default_hstate))
3369 hugetlb_hstate_alloc_pages(&default_hstate);
3370 default_hstate_max_huge_pages = 0;
3375 __setup("default_hugepagesz=", default_hugepagesz_setup);
3377 static unsigned int allowed_mems_nr(struct hstate *h)
3380 unsigned int nr = 0;
3381 nodemask_t *mpol_allowed;
3382 unsigned int *array = h->free_huge_pages_node;
3383 gfp_t gfp_mask = htlb_alloc_mask(h);
3385 mpol_allowed = policy_nodemask_current(gfp_mask);
3387 for_each_node_mask(node, cpuset_current_mems_allowed) {
3388 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3395 #ifdef CONFIG_SYSCTL
3396 static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3397 void *buffer, size_t *length,
3398 loff_t *ppos, unsigned long *out)
3400 struct ctl_table dup_table;
3403 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3404 * can duplicate the @table and alter the duplicate of it.
3407 dup_table.data = out;
3409 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3412 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3413 struct ctl_table *table, int write,
3414 void *buffer, size_t *length, loff_t *ppos)
3416 struct hstate *h = &default_hstate;
3417 unsigned long tmp = h->max_huge_pages;
3420 if (!hugepages_supported())
3423 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3429 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3430 NUMA_NO_NODE, tmp, *length);
3435 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3436 void *buffer, size_t *length, loff_t *ppos)
3439 return hugetlb_sysctl_handler_common(false, table, write,
3440 buffer, length, ppos);
3444 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3445 void *buffer, size_t *length, loff_t *ppos)
3447 return hugetlb_sysctl_handler_common(true, table, write,
3448 buffer, length, ppos);
3450 #endif /* CONFIG_NUMA */
3452 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3453 void *buffer, size_t *length, loff_t *ppos)
3455 struct hstate *h = &default_hstate;
3459 if (!hugepages_supported())
3462 tmp = h->nr_overcommit_huge_pages;
3464 if (write && hstate_is_gigantic(h))
3467 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3473 spin_lock(&hugetlb_lock);
3474 h->nr_overcommit_huge_pages = tmp;
3475 spin_unlock(&hugetlb_lock);
3481 #endif /* CONFIG_SYSCTL */
3483 void hugetlb_report_meminfo(struct seq_file *m)
3486 unsigned long total = 0;
3488 if (!hugepages_supported())
3491 for_each_hstate(h) {
3492 unsigned long count = h->nr_huge_pages;
3494 total += huge_page_size(h) * count;
3496 if (h == &default_hstate)
3498 "HugePages_Total: %5lu\n"
3499 "HugePages_Free: %5lu\n"
3500 "HugePages_Rsvd: %5lu\n"
3501 "HugePages_Surp: %5lu\n"
3502 "Hugepagesize: %8lu kB\n",
3506 h->surplus_huge_pages,
3507 huge_page_size(h) / SZ_1K);
3510 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3513 int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3515 struct hstate *h = &default_hstate;
3517 if (!hugepages_supported())
3520 return sysfs_emit_at(buf, len,
3521 "Node %d HugePages_Total: %5u\n"
3522 "Node %d HugePages_Free: %5u\n"
3523 "Node %d HugePages_Surp: %5u\n",
3524 nid, h->nr_huge_pages_node[nid],
3525 nid, h->free_huge_pages_node[nid],
3526 nid, h->surplus_huge_pages_node[nid]);
3529 void hugetlb_show_meminfo(void)
3534 if (!hugepages_supported())
3537 for_each_node_state(nid, N_MEMORY)
3539 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3541 h->nr_huge_pages_node[nid],
3542 h->free_huge_pages_node[nid],
3543 h->surplus_huge_pages_node[nid],
3544 huge_page_size(h) / SZ_1K);
3547 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3549 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3550 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3553 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3554 unsigned long hugetlb_total_pages(void)
3557 unsigned long nr_total_pages = 0;
3560 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3561 return nr_total_pages;
3564 static int hugetlb_acct_memory(struct hstate *h, long delta)
3571 spin_lock(&hugetlb_lock);
3573 * When cpuset is configured, it breaks the strict hugetlb page
3574 * reservation as the accounting is done on a global variable. Such
3575 * reservation is completely rubbish in the presence of cpuset because
3576 * the reservation is not checked against page availability for the
3577 * current cpuset. Application can still potentially OOM'ed by kernel
3578 * with lack of free htlb page in cpuset that the task is in.
3579 * Attempt to enforce strict accounting with cpuset is almost
3580 * impossible (or too ugly) because cpuset is too fluid that
3581 * task or memory node can be dynamically moved between cpusets.
3583 * The change of semantics for shared hugetlb mapping with cpuset is
3584 * undesirable. However, in order to preserve some of the semantics,
3585 * we fall back to check against current free page availability as
3586 * a best attempt and hopefully to minimize the impact of changing
3587 * semantics that cpuset has.
3589 * Apart from cpuset, we also have memory policy mechanism that
3590 * also determines from which node the kernel will allocate memory
3591 * in a NUMA system. So similar to cpuset, we also should consider
3592 * the memory policy of the current task. Similar to the description
3596 if (gather_surplus_pages(h, delta) < 0)
3599 if (delta > allowed_mems_nr(h)) {
3600 return_unused_surplus_pages(h, delta);
3607 return_unused_surplus_pages(h, (unsigned long) -delta);
3610 spin_unlock(&hugetlb_lock);
3614 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3616 struct resv_map *resv = vma_resv_map(vma);
3619 * This new VMA should share its siblings reservation map if present.
3620 * The VMA will only ever have a valid reservation map pointer where
3621 * it is being copied for another still existing VMA. As that VMA
3622 * has a reference to the reservation map it cannot disappear until
3623 * after this open call completes. It is therefore safe to take a
3624 * new reference here without additional locking.
3626 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3627 kref_get(&resv->refs);
3630 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3632 struct hstate *h = hstate_vma(vma);
3633 struct resv_map *resv = vma_resv_map(vma);
3634 struct hugepage_subpool *spool = subpool_vma(vma);
3635 unsigned long reserve, start, end;
3638 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3641 start = vma_hugecache_offset(h, vma, vma->vm_start);
3642 end = vma_hugecache_offset(h, vma, vma->vm_end);
3644 reserve = (end - start) - region_count(resv, start, end);
3645 hugetlb_cgroup_uncharge_counter(resv, start, end);
3648 * Decrement reserve counts. The global reserve count may be
3649 * adjusted if the subpool has a minimum size.
3651 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3652 hugetlb_acct_memory(h, -gbl_reserve);
3655 kref_put(&resv->refs, resv_map_release);
3658 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3660 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3665 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3667 return huge_page_size(hstate_vma(vma));
3671 * We cannot handle pagefaults against hugetlb pages at all. They cause
3672 * handle_mm_fault() to try to instantiate regular-sized pages in the
3673 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3676 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3683 * When a new function is introduced to vm_operations_struct and added
3684 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3685 * This is because under System V memory model, mappings created via
3686 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3687 * their original vm_ops are overwritten with shm_vm_ops.
3689 const struct vm_operations_struct hugetlb_vm_ops = {
3690 .fault = hugetlb_vm_op_fault,
3691 .open = hugetlb_vm_op_open,
3692 .close = hugetlb_vm_op_close,
3693 .may_split = hugetlb_vm_op_split,
3694 .pagesize = hugetlb_vm_op_pagesize,
3697 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3703 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3704 vma->vm_page_prot)));
3706 entry = huge_pte_wrprotect(mk_huge_pte(page,
3707 vma->vm_page_prot));
3709 entry = pte_mkyoung(entry);
3710 entry = pte_mkhuge(entry);
3711 entry = arch_make_huge_pte(entry, vma, page, writable);
3716 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3717 unsigned long address, pte_t *ptep)
3721 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3722 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3723 update_mmu_cache(vma, address, ptep);
3726 bool is_hugetlb_entry_migration(pte_t pte)
3730 if (huge_pte_none(pte) || pte_present(pte))
3732 swp = pte_to_swp_entry(pte);
3733 if (is_migration_entry(swp))
3739 static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3743 if (huge_pte_none(pte) || pte_present(pte))
3745 swp = pte_to_swp_entry(pte);
3746 if (is_hwpoison_entry(swp))
3753 hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
3754 struct page *new_page)
3756 __SetPageUptodate(new_page);
3757 set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1));
3758 hugepage_add_new_anon_rmap(new_page, vma, addr);
3759 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
3760 ClearHPageRestoreReserve(new_page);
3761 SetHPageMigratable(new_page);
3764 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3765 struct vm_area_struct *vma)
3767 pte_t *src_pte, *dst_pte, entry, dst_entry;
3768 struct page *ptepage;
3770 bool cow = is_cow_mapping(vma->vm_flags);
3771 struct hstate *h = hstate_vma(vma);
3772 unsigned long sz = huge_page_size(h);
3773 unsigned long npages = pages_per_huge_page(h);
3774 struct address_space *mapping = vma->vm_file->f_mapping;
3775 struct mmu_notifier_range range;
3779 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3782 mmu_notifier_invalidate_range_start(&range);
3785 * For shared mappings i_mmap_rwsem must be held to call
3786 * huge_pte_alloc, otherwise the returned ptep could go
3787 * away if part of a shared pmd and another thread calls
3790 i_mmap_lock_read(mapping);
3793 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3794 spinlock_t *src_ptl, *dst_ptl;
3795 src_pte = huge_pte_offset(src, addr, sz);
3798 dst_pte = huge_pte_alloc(dst, addr, sz);
3805 * If the pagetables are shared don't copy or take references.
3806 * dst_pte == src_pte is the common case of src/dest sharing.
3808 * However, src could have 'unshared' and dst shares with
3809 * another vma. If dst_pte !none, this implies sharing.
3810 * Check here before taking page table lock, and once again
3811 * after taking the lock below.
3813 dst_entry = huge_ptep_get(dst_pte);
3814 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3817 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3818 src_ptl = huge_pte_lockptr(h, src, src_pte);
3819 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3820 entry = huge_ptep_get(src_pte);
3821 dst_entry = huge_ptep_get(dst_pte);
3823 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3825 * Skip if src entry none. Also, skip in the
3826 * unlikely case dst entry !none as this implies
3827 * sharing with another vma.
3830 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3831 is_hugetlb_entry_hwpoisoned(entry))) {
3832 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3834 if (is_write_migration_entry(swp_entry) && cow) {
3836 * COW mappings require pages in both
3837 * parent and child to be set to read.
3839 make_migration_entry_read(&swp_entry);
3840 entry = swp_entry_to_pte(swp_entry);
3841 set_huge_swap_pte_at(src, addr, src_pte,
3844 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3846 entry = huge_ptep_get(src_pte);
3847 ptepage = pte_page(entry);
3851 * This is a rare case where we see pinned hugetlb
3852 * pages while they're prone to COW. We need to do the
3853 * COW earlier during fork.
3855 * When pre-allocating the page or copying data, we
3856 * need to be without the pgtable locks since we could
3857 * sleep during the process.
3859 if (unlikely(page_needs_cow_for_dma(vma, ptepage))) {
3860 pte_t src_pte_old = entry;
3863 spin_unlock(src_ptl);
3864 spin_unlock(dst_ptl);
3865 /* Do not use reserve as it's private owned */
3866 new = alloc_huge_page(vma, addr, 1);
3872 copy_user_huge_page(new, ptepage, addr, vma,
3876 /* Install the new huge page if src pte stable */
3877 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3878 src_ptl = huge_pte_lockptr(h, src, src_pte);
3879 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3880 entry = huge_ptep_get(src_pte);
3881 if (!pte_same(src_pte_old, entry)) {
3883 /* dst_entry won't change as in child */
3886 hugetlb_install_page(vma, dst_pte, addr, new);
3887 spin_unlock(src_ptl);
3888 spin_unlock(dst_ptl);
3894 * No need to notify as we are downgrading page
3895 * table protection not changing it to point
3898 * See Documentation/vm/mmu_notifier.rst
3900 huge_ptep_set_wrprotect(src, addr, src_pte);
3903 page_dup_rmap(ptepage, true);
3904 set_huge_pte_at(dst, addr, dst_pte, entry);
3905 hugetlb_count_add(npages, dst);
3907 spin_unlock(src_ptl);
3908 spin_unlock(dst_ptl);
3912 mmu_notifier_invalidate_range_end(&range);
3914 i_mmap_unlock_read(mapping);
3919 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3920 unsigned long start, unsigned long end,
3921 struct page *ref_page)
3923 struct mm_struct *mm = vma->vm_mm;
3924 unsigned long address;
3929 struct hstate *h = hstate_vma(vma);
3930 unsigned long sz = huge_page_size(h);
3931 struct mmu_notifier_range range;
3933 WARN_ON(!is_vm_hugetlb_page(vma));
3934 BUG_ON(start & ~huge_page_mask(h));
3935 BUG_ON(end & ~huge_page_mask(h));
3938 * This is a hugetlb vma, all the pte entries should point
3941 tlb_change_page_size(tlb, sz);
3942 tlb_start_vma(tlb, vma);
3945 * If sharing possible, alert mmu notifiers of worst case.
3947 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
3949 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
3950 mmu_notifier_invalidate_range_start(&range);
3952 for (; address < end; address += sz) {
3953 ptep = huge_pte_offset(mm, address, sz);
3957 ptl = huge_pte_lock(h, mm, ptep);
3958 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3961 * We just unmapped a page of PMDs by clearing a PUD.
3962 * The caller's TLB flush range should cover this area.
3967 pte = huge_ptep_get(ptep);
3968 if (huge_pte_none(pte)) {
3974 * Migrating hugepage or HWPoisoned hugepage is already
3975 * unmapped and its refcount is dropped, so just clear pte here.
3977 if (unlikely(!pte_present(pte))) {
3978 huge_pte_clear(mm, address, ptep, sz);
3983 page = pte_page(pte);
3985 * If a reference page is supplied, it is because a specific
3986 * page is being unmapped, not a range. Ensure the page we
3987 * are about to unmap is the actual page of interest.
3990 if (page != ref_page) {
3995 * Mark the VMA as having unmapped its page so that
3996 * future faults in this VMA will fail rather than
3997 * looking like data was lost
3999 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4002 pte = huge_ptep_get_and_clear(mm, address, ptep);
4003 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4004 if (huge_pte_dirty(pte))
4005 set_page_dirty(page);
4007 hugetlb_count_sub(pages_per_huge_page(h), mm);
4008 page_remove_rmap(page, true);
4011 tlb_remove_page_size(tlb, page, huge_page_size(h));
4013 * Bail out after unmapping reference page if supplied
4018 mmu_notifier_invalidate_range_end(&range);
4019 tlb_end_vma(tlb, vma);
4022 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4023 struct vm_area_struct *vma, unsigned long start,
4024 unsigned long end, struct page *ref_page)
4026 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4029 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4030 * test will fail on a vma being torn down, and not grab a page table
4031 * on its way out. We're lucky that the flag has such an appropriate
4032 * name, and can in fact be safely cleared here. We could clear it
4033 * before the __unmap_hugepage_range above, but all that's necessary
4034 * is to clear it before releasing the i_mmap_rwsem. This works
4035 * because in the context this is called, the VMA is about to be
4036 * destroyed and the i_mmap_rwsem is held.
4038 vma->vm_flags &= ~VM_MAYSHARE;
4041 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4042 unsigned long end, struct page *ref_page)
4044 struct mmu_gather tlb;
4046 tlb_gather_mmu(&tlb, vma->vm_mm);
4047 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4048 tlb_finish_mmu(&tlb);
4052 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4053 * mapping it owns the reserve page for. The intention is to unmap the page
4054 * from other VMAs and let the children be SIGKILLed if they are faulting the
4057 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4058 struct page *page, unsigned long address)
4060 struct hstate *h = hstate_vma(vma);
4061 struct vm_area_struct *iter_vma;
4062 struct address_space *mapping;
4066 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4067 * from page cache lookup which is in HPAGE_SIZE units.
4069 address = address & huge_page_mask(h);
4070 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4072 mapping = vma->vm_file->f_mapping;
4075 * Take the mapping lock for the duration of the table walk. As
4076 * this mapping should be shared between all the VMAs,
4077 * __unmap_hugepage_range() is called as the lock is already held
4079 i_mmap_lock_write(mapping);
4080 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4081 /* Do not unmap the current VMA */
4082 if (iter_vma == vma)
4086 * Shared VMAs have their own reserves and do not affect
4087 * MAP_PRIVATE accounting but it is possible that a shared
4088 * VMA is using the same page so check and skip such VMAs.
4090 if (iter_vma->vm_flags & VM_MAYSHARE)
4094 * Unmap the page from other VMAs without their own reserves.
4095 * They get marked to be SIGKILLed if they fault in these
4096 * areas. This is because a future no-page fault on this VMA
4097 * could insert a zeroed page instead of the data existing
4098 * from the time of fork. This would look like data corruption
4100 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4101 unmap_hugepage_range(iter_vma, address,
4102 address + huge_page_size(h), page);
4104 i_mmap_unlock_write(mapping);
4108 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4109 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4110 * cannot race with other handlers or page migration.
4111 * Keep the pte_same checks anyway to make transition from the mutex easier.
4113 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4114 unsigned long address, pte_t *ptep,
4115 struct page *pagecache_page, spinlock_t *ptl)
4118 struct hstate *h = hstate_vma(vma);
4119 struct page *old_page, *new_page;
4120 int outside_reserve = 0;
4122 unsigned long haddr = address & huge_page_mask(h);
4123 struct mmu_notifier_range range;
4125 pte = huge_ptep_get(ptep);
4126 old_page = pte_page(pte);
4129 /* If no-one else is actually using this page, avoid the copy
4130 * and just make the page writable */
4131 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4132 page_move_anon_rmap(old_page, vma);
4133 set_huge_ptep_writable(vma, haddr, ptep);
4138 * If the process that created a MAP_PRIVATE mapping is about to
4139 * perform a COW due to a shared page count, attempt to satisfy
4140 * the allocation without using the existing reserves. The pagecache
4141 * page is used to determine if the reserve at this address was
4142 * consumed or not. If reserves were used, a partial faulted mapping
4143 * at the time of fork() could consume its reserves on COW instead
4144 * of the full address range.
4146 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4147 old_page != pagecache_page)
4148 outside_reserve = 1;
4153 * Drop page table lock as buddy allocator may be called. It will
4154 * be acquired again before returning to the caller, as expected.
4157 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4159 if (IS_ERR(new_page)) {
4161 * If a process owning a MAP_PRIVATE mapping fails to COW,
4162 * it is due to references held by a child and an insufficient
4163 * huge page pool. To guarantee the original mappers
4164 * reliability, unmap the page from child processes. The child
4165 * may get SIGKILLed if it later faults.
4167 if (outside_reserve) {
4168 struct address_space *mapping = vma->vm_file->f_mapping;
4173 BUG_ON(huge_pte_none(pte));
4175 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4176 * unmapping. unmapping needs to hold i_mmap_rwsem
4177 * in write mode. Dropping i_mmap_rwsem in read mode
4178 * here is OK as COW mappings do not interact with
4181 * Reacquire both after unmap operation.
4183 idx = vma_hugecache_offset(h, vma, haddr);
4184 hash = hugetlb_fault_mutex_hash(mapping, idx);
4185 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4186 i_mmap_unlock_read(mapping);
4188 unmap_ref_private(mm, vma, old_page, haddr);
4190 i_mmap_lock_read(mapping);
4191 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4193 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4195 pte_same(huge_ptep_get(ptep), pte)))
4196 goto retry_avoidcopy;
4198 * race occurs while re-acquiring page table
4199 * lock, and our job is done.
4204 ret = vmf_error(PTR_ERR(new_page));
4205 goto out_release_old;
4209 * When the original hugepage is shared one, it does not have
4210 * anon_vma prepared.
4212 if (unlikely(anon_vma_prepare(vma))) {
4214 goto out_release_all;
4217 copy_user_huge_page(new_page, old_page, address, vma,
4218 pages_per_huge_page(h));
4219 __SetPageUptodate(new_page);
4221 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4222 haddr + huge_page_size(h));
4223 mmu_notifier_invalidate_range_start(&range);
4226 * Retake the page table lock to check for racing updates
4227 * before the page tables are altered
4230 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4231 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4232 ClearHPageRestoreReserve(new_page);
4235 huge_ptep_clear_flush(vma, haddr, ptep);
4236 mmu_notifier_invalidate_range(mm, range.start, range.end);
4237 set_huge_pte_at(mm, haddr, ptep,
4238 make_huge_pte(vma, new_page, 1));
4239 page_remove_rmap(old_page, true);
4240 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4241 SetHPageMigratable(new_page);
4242 /* Make the old page be freed below */
4243 new_page = old_page;
4246 mmu_notifier_invalidate_range_end(&range);
4248 restore_reserve_on_error(h, vma, haddr, new_page);
4253 spin_lock(ptl); /* Caller expects lock to be held */
4257 /* Return the pagecache page at a given address within a VMA */
4258 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4259 struct vm_area_struct *vma, unsigned long address)
4261 struct address_space *mapping;
4264 mapping = vma->vm_file->f_mapping;
4265 idx = vma_hugecache_offset(h, vma, address);
4267 return find_lock_page(mapping, idx);
4271 * Return whether there is a pagecache page to back given address within VMA.
4272 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4274 static bool hugetlbfs_pagecache_present(struct hstate *h,
4275 struct vm_area_struct *vma, unsigned long address)
4277 struct address_space *mapping;
4281 mapping = vma->vm_file->f_mapping;
4282 idx = vma_hugecache_offset(h, vma, address);
4284 page = find_get_page(mapping, idx);
4287 return page != NULL;
4290 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4293 struct inode *inode = mapping->host;
4294 struct hstate *h = hstate_inode(inode);
4295 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4299 ClearHPageRestoreReserve(page);
4302 * set page dirty so that it will not be removed from cache/file
4303 * by non-hugetlbfs specific code paths.
4305 set_page_dirty(page);
4307 spin_lock(&inode->i_lock);
4308 inode->i_blocks += blocks_per_huge_page(h);
4309 spin_unlock(&inode->i_lock);
4313 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4314 struct vm_area_struct *vma,
4315 struct address_space *mapping, pgoff_t idx,
4316 unsigned long address, pte_t *ptep, unsigned int flags)
4318 struct hstate *h = hstate_vma(vma);
4319 vm_fault_t ret = VM_FAULT_SIGBUS;
4325 unsigned long haddr = address & huge_page_mask(h);
4326 bool new_page = false;
4329 * Currently, we are forced to kill the process in the event the
4330 * original mapper has unmapped pages from the child due to a failed
4331 * COW. Warn that such a situation has occurred as it may not be obvious
4333 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4334 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4340 * We can not race with truncation due to holding i_mmap_rwsem.
4341 * i_size is modified when holding i_mmap_rwsem, so check here
4342 * once for faults beyond end of file.
4344 size = i_size_read(mapping->host) >> huge_page_shift(h);
4349 page = find_lock_page(mapping, idx);
4352 * Check for page in userfault range
4354 if (userfaultfd_missing(vma)) {
4356 struct vm_fault vmf = {
4361 * Hard to debug if it ends up being
4362 * used by a callee that assumes
4363 * something about the other
4364 * uninitialized fields... same as in
4370 * hugetlb_fault_mutex and i_mmap_rwsem must be
4371 * dropped before handling userfault. Reacquire
4372 * after handling fault to make calling code simpler.
4374 hash = hugetlb_fault_mutex_hash(mapping, idx);
4375 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4376 i_mmap_unlock_read(mapping);
4377 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4378 i_mmap_lock_read(mapping);
4379 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4383 page = alloc_huge_page(vma, haddr, 0);
4386 * Returning error will result in faulting task being
4387 * sent SIGBUS. The hugetlb fault mutex prevents two
4388 * tasks from racing to fault in the same page which
4389 * could result in false unable to allocate errors.
4390 * Page migration does not take the fault mutex, but
4391 * does a clear then write of pte's under page table
4392 * lock. Page fault code could race with migration,
4393 * notice the clear pte and try to allocate a page
4394 * here. Before returning error, get ptl and make
4395 * sure there really is no pte entry.
4397 ptl = huge_pte_lock(h, mm, ptep);
4398 if (!huge_pte_none(huge_ptep_get(ptep))) {
4404 ret = vmf_error(PTR_ERR(page));
4407 clear_huge_page(page, address, pages_per_huge_page(h));
4408 __SetPageUptodate(page);
4411 if (vma->vm_flags & VM_MAYSHARE) {
4412 int err = huge_add_to_page_cache(page, mapping, idx);
4421 if (unlikely(anon_vma_prepare(vma))) {
4423 goto backout_unlocked;
4429 * If memory error occurs between mmap() and fault, some process
4430 * don't have hwpoisoned swap entry for errored virtual address.
4431 * So we need to block hugepage fault by PG_hwpoison bit check.
4433 if (unlikely(PageHWPoison(page))) {
4434 ret = VM_FAULT_HWPOISON_LARGE |
4435 VM_FAULT_SET_HINDEX(hstate_index(h));
4436 goto backout_unlocked;
4441 * If we are going to COW a private mapping later, we examine the
4442 * pending reservations for this page now. This will ensure that
4443 * any allocations necessary to record that reservation occur outside
4446 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4447 if (vma_needs_reservation(h, vma, haddr) < 0) {
4449 goto backout_unlocked;
4451 /* Just decrements count, does not deallocate */
4452 vma_end_reservation(h, vma, haddr);
4455 ptl = huge_pte_lock(h, mm, ptep);
4457 if (!huge_pte_none(huge_ptep_get(ptep)))
4461 ClearHPageRestoreReserve(page);
4462 hugepage_add_new_anon_rmap(page, vma, haddr);
4464 page_dup_rmap(page, true);
4465 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4466 && (vma->vm_flags & VM_SHARED)));
4467 set_huge_pte_at(mm, haddr, ptep, new_pte);
4469 hugetlb_count_add(pages_per_huge_page(h), mm);
4470 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4471 /* Optimization, do the COW without a second fault */
4472 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4478 * Only set HPageMigratable in newly allocated pages. Existing pages
4479 * found in the pagecache may not have HPageMigratableset if they have
4480 * been isolated for migration.
4483 SetHPageMigratable(page);
4493 restore_reserve_on_error(h, vma, haddr, page);
4499 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4501 unsigned long key[2];
4504 key[0] = (unsigned long) mapping;
4507 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4509 return hash & (num_fault_mutexes - 1);
4513 * For uniprocessor systems we always use a single mutex, so just
4514 * return 0 and avoid the hashing overhead.
4516 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4522 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4523 unsigned long address, unsigned int flags)
4530 struct page *page = NULL;
4531 struct page *pagecache_page = NULL;
4532 struct hstate *h = hstate_vma(vma);
4533 struct address_space *mapping;
4534 int need_wait_lock = 0;
4535 unsigned long haddr = address & huge_page_mask(h);
4537 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4540 * Since we hold no locks, ptep could be stale. That is
4541 * OK as we are only making decisions based on content and
4542 * not actually modifying content here.
4544 entry = huge_ptep_get(ptep);
4545 if (unlikely(is_hugetlb_entry_migration(entry))) {
4546 migration_entry_wait_huge(vma, mm, ptep);
4548 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4549 return VM_FAULT_HWPOISON_LARGE |
4550 VM_FAULT_SET_HINDEX(hstate_index(h));
4554 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4555 * until finished with ptep. This serves two purposes:
4556 * 1) It prevents huge_pmd_unshare from being called elsewhere
4557 * and making the ptep no longer valid.
4558 * 2) It synchronizes us with i_size modifications during truncation.
4560 * ptep could have already be assigned via huge_pte_offset. That
4561 * is OK, as huge_pte_alloc will return the same value unless
4562 * something has changed.
4564 mapping = vma->vm_file->f_mapping;
4565 i_mmap_lock_read(mapping);
4566 ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
4568 i_mmap_unlock_read(mapping);
4569 return VM_FAULT_OOM;
4573 * Serialize hugepage allocation and instantiation, so that we don't
4574 * get spurious allocation failures if two CPUs race to instantiate
4575 * the same page in the page cache.
4577 idx = vma_hugecache_offset(h, vma, haddr);
4578 hash = hugetlb_fault_mutex_hash(mapping, idx);
4579 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4581 entry = huge_ptep_get(ptep);
4582 if (huge_pte_none(entry)) {
4583 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4590 * entry could be a migration/hwpoison entry at this point, so this
4591 * check prevents the kernel from going below assuming that we have
4592 * an active hugepage in pagecache. This goto expects the 2nd page
4593 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4594 * properly handle it.
4596 if (!pte_present(entry))
4600 * If we are going to COW the mapping later, we examine the pending
4601 * reservations for this page now. This will ensure that any
4602 * allocations necessary to record that reservation occur outside the
4603 * spinlock. For private mappings, we also lookup the pagecache
4604 * page now as it is used to determine if a reservation has been
4607 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4608 if (vma_needs_reservation(h, vma, haddr) < 0) {
4612 /* Just decrements count, does not deallocate */
4613 vma_end_reservation(h, vma, haddr);
4615 if (!(vma->vm_flags & VM_MAYSHARE))
4616 pagecache_page = hugetlbfs_pagecache_page(h,
4620 ptl = huge_pte_lock(h, mm, ptep);
4622 /* Check for a racing update before calling hugetlb_cow */
4623 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4627 * hugetlb_cow() requires page locks of pte_page(entry) and
4628 * pagecache_page, so here we need take the former one
4629 * when page != pagecache_page or !pagecache_page.
4631 page = pte_page(entry);
4632 if (page != pagecache_page)
4633 if (!trylock_page(page)) {
4640 if (flags & FAULT_FLAG_WRITE) {
4641 if (!huge_pte_write(entry)) {
4642 ret = hugetlb_cow(mm, vma, address, ptep,
4643 pagecache_page, ptl);
4646 entry = huge_pte_mkdirty(entry);
4648 entry = pte_mkyoung(entry);
4649 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4650 flags & FAULT_FLAG_WRITE))
4651 update_mmu_cache(vma, haddr, ptep);
4653 if (page != pagecache_page)
4659 if (pagecache_page) {
4660 unlock_page(pagecache_page);
4661 put_page(pagecache_page);
4664 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4665 i_mmap_unlock_read(mapping);
4667 * Generally it's safe to hold refcount during waiting page lock. But
4668 * here we just wait to defer the next page fault to avoid busy loop and
4669 * the page is not used after unlocked before returning from the current
4670 * page fault. So we are safe from accessing freed page, even if we wait
4671 * here without taking refcount.
4674 wait_on_page_locked(page);
4679 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4680 * modifications for huge pages.
4682 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4684 struct vm_area_struct *dst_vma,
4685 unsigned long dst_addr,
4686 unsigned long src_addr,
4687 struct page **pagep)
4689 struct address_space *mapping;
4692 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4693 struct hstate *h = hstate_vma(dst_vma);
4701 page = alloc_huge_page(dst_vma, dst_addr, 0);
4705 ret = copy_huge_page_from_user(page,
4706 (const void __user *) src_addr,
4707 pages_per_huge_page(h), false);
4709 /* fallback to copy_from_user outside mmap_lock */
4710 if (unlikely(ret)) {
4713 /* don't free the page */
4722 * The memory barrier inside __SetPageUptodate makes sure that
4723 * preceding stores to the page contents become visible before
4724 * the set_pte_at() write.
4726 __SetPageUptodate(page);
4728 mapping = dst_vma->vm_file->f_mapping;
4729 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4732 * If shared, add to page cache
4735 size = i_size_read(mapping->host) >> huge_page_shift(h);
4738 goto out_release_nounlock;
4741 * Serialization between remove_inode_hugepages() and
4742 * huge_add_to_page_cache() below happens through the
4743 * hugetlb_fault_mutex_table that here must be hold by
4746 ret = huge_add_to_page_cache(page, mapping, idx);
4748 goto out_release_nounlock;
4751 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4755 * Recheck the i_size after holding PT lock to make sure not
4756 * to leave any page mapped (as page_mapped()) beyond the end
4757 * of the i_size (remove_inode_hugepages() is strict about
4758 * enforcing that). If we bail out here, we'll also leave a
4759 * page in the radix tree in the vm_shared case beyond the end
4760 * of the i_size, but remove_inode_hugepages() will take care
4761 * of it as soon as we drop the hugetlb_fault_mutex_table.
4763 size = i_size_read(mapping->host) >> huge_page_shift(h);
4766 goto out_release_unlock;
4769 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4770 goto out_release_unlock;
4773 page_dup_rmap(page, true);
4775 ClearHPageRestoreReserve(page);
4776 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4779 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4780 if (dst_vma->vm_flags & VM_WRITE)
4781 _dst_pte = huge_pte_mkdirty(_dst_pte);
4782 _dst_pte = pte_mkyoung(_dst_pte);
4784 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4786 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4787 dst_vma->vm_flags & VM_WRITE);
4788 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4790 /* No need to invalidate - it was non-present before */
4791 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4794 SetHPageMigratable(page);
4804 out_release_nounlock:
4809 static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
4810 int refs, struct page **pages,
4811 struct vm_area_struct **vmas)
4815 for (nr = 0; nr < refs; nr++) {
4817 pages[nr] = mem_map_offset(page, nr);
4823 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4824 struct page **pages, struct vm_area_struct **vmas,
4825 unsigned long *position, unsigned long *nr_pages,
4826 long i, unsigned int flags, int *locked)
4828 unsigned long pfn_offset;
4829 unsigned long vaddr = *position;
4830 unsigned long remainder = *nr_pages;
4831 struct hstate *h = hstate_vma(vma);
4832 int err = -EFAULT, refs;
4834 while (vaddr < vma->vm_end && remainder) {
4836 spinlock_t *ptl = NULL;
4841 * If we have a pending SIGKILL, don't keep faulting pages and
4842 * potentially allocating memory.
4844 if (fatal_signal_pending(current)) {
4850 * Some archs (sparc64, sh*) have multiple pte_ts to
4851 * each hugepage. We have to make sure we get the
4852 * first, for the page indexing below to work.
4854 * Note that page table lock is not held when pte is null.
4856 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4859 ptl = huge_pte_lock(h, mm, pte);
4860 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4863 * When coredumping, it suits get_dump_page if we just return
4864 * an error where there's an empty slot with no huge pagecache
4865 * to back it. This way, we avoid allocating a hugepage, and
4866 * the sparse dumpfile avoids allocating disk blocks, but its
4867 * huge holes still show up with zeroes where they need to be.
4869 if (absent && (flags & FOLL_DUMP) &&
4870 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4878 * We need call hugetlb_fault for both hugepages under migration
4879 * (in which case hugetlb_fault waits for the migration,) and
4880 * hwpoisoned hugepages (in which case we need to prevent the
4881 * caller from accessing to them.) In order to do this, we use
4882 * here is_swap_pte instead of is_hugetlb_entry_migration and
4883 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4884 * both cases, and because we can't follow correct pages
4885 * directly from any kind of swap entries.
4887 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4888 ((flags & FOLL_WRITE) &&
4889 !huge_pte_write(huge_ptep_get(pte)))) {
4891 unsigned int fault_flags = 0;
4895 if (flags & FOLL_WRITE)
4896 fault_flags |= FAULT_FLAG_WRITE;
4898 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4899 FAULT_FLAG_KILLABLE;
4900 if (flags & FOLL_NOWAIT)
4901 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4902 FAULT_FLAG_RETRY_NOWAIT;
4903 if (flags & FOLL_TRIED) {
4905 * Note: FAULT_FLAG_ALLOW_RETRY and
4906 * FAULT_FLAG_TRIED can co-exist
4908 fault_flags |= FAULT_FLAG_TRIED;
4910 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4911 if (ret & VM_FAULT_ERROR) {
4912 err = vm_fault_to_errno(ret, flags);
4916 if (ret & VM_FAULT_RETRY) {
4918 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4922 * VM_FAULT_RETRY must not return an
4923 * error, it will return zero
4926 * No need to update "position" as the
4927 * caller will not check it after
4928 * *nr_pages is set to 0.
4935 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4936 page = pte_page(huge_ptep_get(pte));
4939 * If subpage information not requested, update counters
4940 * and skip the same_page loop below.
4942 if (!pages && !vmas && !pfn_offset &&
4943 (vaddr + huge_page_size(h) < vma->vm_end) &&
4944 (remainder >= pages_per_huge_page(h))) {
4945 vaddr += huge_page_size(h);
4946 remainder -= pages_per_huge_page(h);
4947 i += pages_per_huge_page(h);
4952 refs = min3(pages_per_huge_page(h) - pfn_offset,
4953 (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
4956 record_subpages_vmas(mem_map_offset(page, pfn_offset),
4958 likely(pages) ? pages + i : NULL,
4959 vmas ? vmas + i : NULL);
4963 * try_grab_compound_head() should always succeed here,
4964 * because: a) we hold the ptl lock, and b) we've just
4965 * checked that the huge page is present in the page
4966 * tables. If the huge page is present, then the tail
4967 * pages must also be present. The ptl prevents the
4968 * head page and tail pages from being rearranged in
4969 * any way. So this page must be available at this
4970 * point, unless the page refcount overflowed:
4972 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
4982 vaddr += (refs << PAGE_SHIFT);
4988 *nr_pages = remainder;
4990 * setting position is actually required only if remainder is
4991 * not zero but it's faster not to add a "if (remainder)"
4999 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
5001 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
5004 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
5007 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5008 unsigned long address, unsigned long end, pgprot_t newprot)
5010 struct mm_struct *mm = vma->vm_mm;
5011 unsigned long start = address;
5014 struct hstate *h = hstate_vma(vma);
5015 unsigned long pages = 0;
5016 bool shared_pmd = false;
5017 struct mmu_notifier_range range;
5020 * In the case of shared PMDs, the area to flush could be beyond
5021 * start/end. Set range.start/range.end to cover the maximum possible
5022 * range if PMD sharing is possible.
5024 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5025 0, vma, mm, start, end);
5026 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5028 BUG_ON(address >= end);
5029 flush_cache_range(vma, range.start, range.end);
5031 mmu_notifier_invalidate_range_start(&range);
5032 i_mmap_lock_write(vma->vm_file->f_mapping);
5033 for (; address < end; address += huge_page_size(h)) {
5035 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5038 ptl = huge_pte_lock(h, mm, ptep);
5039 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5045 pte = huge_ptep_get(ptep);
5046 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5050 if (unlikely(is_hugetlb_entry_migration(pte))) {
5051 swp_entry_t entry = pte_to_swp_entry(pte);
5053 if (is_write_migration_entry(entry)) {
5056 make_migration_entry_read(&entry);
5057 newpte = swp_entry_to_pte(entry);
5058 set_huge_swap_pte_at(mm, address, ptep,
5059 newpte, huge_page_size(h));
5065 if (!huge_pte_none(pte)) {
5068 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5069 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5070 pte = arch_make_huge_pte(pte, vma, NULL, 0);
5071 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5077 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5078 * may have cleared our pud entry and done put_page on the page table:
5079 * once we release i_mmap_rwsem, another task can do the final put_page
5080 * and that page table be reused and filled with junk. If we actually
5081 * did unshare a page of pmds, flush the range corresponding to the pud.
5084 flush_hugetlb_tlb_range(vma, range.start, range.end);
5086 flush_hugetlb_tlb_range(vma, start, end);
5088 * No need to call mmu_notifier_invalidate_range() we are downgrading
5089 * page table protection not changing it to point to a new page.
5091 * See Documentation/vm/mmu_notifier.rst
5093 i_mmap_unlock_write(vma->vm_file->f_mapping);
5094 mmu_notifier_invalidate_range_end(&range);
5096 return pages << h->order;
5099 /* Return true if reservation was successful, false otherwise. */
5100 bool hugetlb_reserve_pages(struct inode *inode,
5102 struct vm_area_struct *vma,
5103 vm_flags_t vm_flags)
5106 struct hstate *h = hstate_inode(inode);
5107 struct hugepage_subpool *spool = subpool_inode(inode);
5108 struct resv_map *resv_map;
5109 struct hugetlb_cgroup *h_cg = NULL;
5110 long gbl_reserve, regions_needed = 0;
5112 /* This should never happen */
5114 VM_WARN(1, "%s called with a negative range\n", __func__);
5119 * Only apply hugepage reservation if asked. At fault time, an
5120 * attempt will be made for VM_NORESERVE to allocate a page
5121 * without using reserves
5123 if (vm_flags & VM_NORESERVE)
5127 * Shared mappings base their reservation on the number of pages that
5128 * are already allocated on behalf of the file. Private mappings need
5129 * to reserve the full area even if read-only as mprotect() may be
5130 * called to make the mapping read-write. Assume !vma is a shm mapping
5132 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5134 * resv_map can not be NULL as hugetlb_reserve_pages is only
5135 * called for inodes for which resv_maps were created (see
5136 * hugetlbfs_get_inode).
5138 resv_map = inode_resv_map(inode);
5140 chg = region_chg(resv_map, from, to, ®ions_needed);
5143 /* Private mapping. */
5144 resv_map = resv_map_alloc();
5150 set_vma_resv_map(vma, resv_map);
5151 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5157 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
5158 chg * pages_per_huge_page(h), &h_cg) < 0)
5161 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5162 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5165 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5169 * There must be enough pages in the subpool for the mapping. If
5170 * the subpool has a minimum size, there may be some global
5171 * reservations already in place (gbl_reserve).
5173 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5174 if (gbl_reserve < 0)
5175 goto out_uncharge_cgroup;
5178 * Check enough hugepages are available for the reservation.
5179 * Hand the pages back to the subpool if there are not
5181 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
5185 * Account for the reservations made. Shared mappings record regions
5186 * that have reservations as they are shared by multiple VMAs.
5187 * When the last VMA disappears, the region map says how much
5188 * the reservation was and the page cache tells how much of
5189 * the reservation was consumed. Private mappings are per-VMA and
5190 * only the consumed reservations are tracked. When the VMA
5191 * disappears, the original reservation is the VMA size and the
5192 * consumed reservations are stored in the map. Hence, nothing
5193 * else has to be done for private mappings here
5195 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5196 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5198 if (unlikely(add < 0)) {
5199 hugetlb_acct_memory(h, -gbl_reserve);
5201 } else if (unlikely(chg > add)) {
5203 * pages in this range were added to the reserve
5204 * map between region_chg and region_add. This
5205 * indicates a race with alloc_huge_page. Adjust
5206 * the subpool and reserve counts modified above
5207 * based on the difference.
5212 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5213 * reference to h_cg->css. See comment below for detail.
5215 hugetlb_cgroup_uncharge_cgroup_rsvd(
5217 (chg - add) * pages_per_huge_page(h), h_cg);
5219 rsv_adjust = hugepage_subpool_put_pages(spool,
5221 hugetlb_acct_memory(h, -rsv_adjust);
5224 * The file_regions will hold their own reference to
5225 * h_cg->css. So we should release the reference held
5226 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5229 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5235 /* put back original number of pages, chg */
5236 (void)hugepage_subpool_put_pages(spool, chg);
5237 out_uncharge_cgroup:
5238 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5239 chg * pages_per_huge_page(h), h_cg);
5241 if (!vma || vma->vm_flags & VM_MAYSHARE)
5242 /* Only call region_abort if the region_chg succeeded but the
5243 * region_add failed or didn't run.
5245 if (chg >= 0 && add < 0)
5246 region_abort(resv_map, from, to, regions_needed);
5247 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5248 kref_put(&resv_map->refs, resv_map_release);
5252 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5255 struct hstate *h = hstate_inode(inode);
5256 struct resv_map *resv_map = inode_resv_map(inode);
5258 struct hugepage_subpool *spool = subpool_inode(inode);
5262 * Since this routine can be called in the evict inode path for all
5263 * hugetlbfs inodes, resv_map could be NULL.
5266 chg = region_del(resv_map, start, end);
5268 * region_del() can fail in the rare case where a region
5269 * must be split and another region descriptor can not be
5270 * allocated. If end == LONG_MAX, it will not fail.
5276 spin_lock(&inode->i_lock);
5277 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5278 spin_unlock(&inode->i_lock);
5281 * If the subpool has a minimum size, the number of global
5282 * reservations to be released may be adjusted.
5284 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5285 hugetlb_acct_memory(h, -gbl_reserve);
5290 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5291 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5292 struct vm_area_struct *vma,
5293 unsigned long addr, pgoff_t idx)
5295 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5297 unsigned long sbase = saddr & PUD_MASK;
5298 unsigned long s_end = sbase + PUD_SIZE;
5300 /* Allow segments to share if only one is marked locked */
5301 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5302 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5305 * match the virtual addresses, permission and the alignment of the
5308 if (pmd_index(addr) != pmd_index(saddr) ||
5309 vm_flags != svm_flags ||
5310 !range_in_vma(svma, sbase, s_end))
5316 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5318 unsigned long base = addr & PUD_MASK;
5319 unsigned long end = base + PUD_SIZE;
5322 * check on proper vm_flags and page table alignment
5324 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5330 * Determine if start,end range within vma could be mapped by shared pmd.
5331 * If yes, adjust start and end to cover range associated with possible
5332 * shared pmd mappings.
5334 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5335 unsigned long *start, unsigned long *end)
5337 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5338 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5341 * vma need span at least one aligned PUD size and the start,end range
5342 * must at least partialy within it.
5344 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5345 (*end <= v_start) || (*start >= v_end))
5348 /* Extend the range to be PUD aligned for a worst case scenario */
5349 if (*start > v_start)
5350 *start = ALIGN_DOWN(*start, PUD_SIZE);
5353 *end = ALIGN(*end, PUD_SIZE);
5357 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5358 * and returns the corresponding pte. While this is not necessary for the
5359 * !shared pmd case because we can allocate the pmd later as well, it makes the
5360 * code much cleaner.
5362 * This routine must be called with i_mmap_rwsem held in at least read mode if
5363 * sharing is possible. For hugetlbfs, this prevents removal of any page
5364 * table entries associated with the address space. This is important as we
5365 * are setting up sharing based on existing page table entries (mappings).
5367 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5368 * huge_pte_alloc know that sharing is not possible and do not take
5369 * i_mmap_rwsem as a performance optimization. This is handled by the
5370 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5371 * only required for subsequent processing.
5373 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5375 struct vm_area_struct *vma = find_vma(mm, addr);
5376 struct address_space *mapping = vma->vm_file->f_mapping;
5377 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5379 struct vm_area_struct *svma;
5380 unsigned long saddr;
5385 if (!vma_shareable(vma, addr))
5386 return (pte_t *)pmd_alloc(mm, pud, addr);
5388 i_mmap_assert_locked(mapping);
5389 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5393 saddr = page_table_shareable(svma, vma, addr, idx);
5395 spte = huge_pte_offset(svma->vm_mm, saddr,
5396 vma_mmu_pagesize(svma));
5398 get_page(virt_to_page(spte));
5407 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5408 if (pud_none(*pud)) {
5409 pud_populate(mm, pud,
5410 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5413 put_page(virt_to_page(spte));
5417 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5422 * unmap huge page backed by shared pte.
5424 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5425 * indicated by page_count > 1, unmap is achieved by clearing pud and
5426 * decrementing the ref count. If count == 1, the pte page is not shared.
5428 * Called with page table lock held and i_mmap_rwsem held in write mode.
5430 * returns: 1 successfully unmapped a shared pte page
5431 * 0 the underlying pte page is not shared, or it is the last user
5433 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5434 unsigned long *addr, pte_t *ptep)
5436 pgd_t *pgd = pgd_offset(mm, *addr);
5437 p4d_t *p4d = p4d_offset(pgd, *addr);
5438 pud_t *pud = pud_offset(p4d, *addr);
5440 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5441 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5442 if (page_count(virt_to_page(ptep)) == 1)
5446 put_page(virt_to_page(ptep));
5448 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5451 #define want_pmd_share() (1)
5452 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5453 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5458 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5459 unsigned long *addr, pte_t *ptep)
5464 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5465 unsigned long *start, unsigned long *end)
5468 #define want_pmd_share() (0)
5469 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5471 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5472 pte_t *huge_pte_alloc(struct mm_struct *mm,
5473 unsigned long addr, unsigned long sz)
5480 pgd = pgd_offset(mm, addr);
5481 p4d = p4d_alloc(mm, pgd, addr);
5484 pud = pud_alloc(mm, p4d, addr);
5486 if (sz == PUD_SIZE) {
5489 BUG_ON(sz != PMD_SIZE);
5490 if (want_pmd_share() && pud_none(*pud))
5491 pte = huge_pmd_share(mm, addr, pud);
5493 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5496 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5502 * huge_pte_offset() - Walk the page table to resolve the hugepage
5503 * entry at address @addr
5505 * Return: Pointer to page table entry (PUD or PMD) for
5506 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5507 * size @sz doesn't match the hugepage size at this level of the page
5510 pte_t *huge_pte_offset(struct mm_struct *mm,
5511 unsigned long addr, unsigned long sz)
5518 pgd = pgd_offset(mm, addr);
5519 if (!pgd_present(*pgd))
5521 p4d = p4d_offset(pgd, addr);
5522 if (!p4d_present(*p4d))
5525 pud = pud_offset(p4d, addr);
5527 /* must be pud huge, non-present or none */
5528 return (pte_t *)pud;
5529 if (!pud_present(*pud))
5531 /* must have a valid entry and size to go further */
5533 pmd = pmd_offset(pud, addr);
5534 /* must be pmd huge, non-present or none */
5535 return (pte_t *)pmd;
5538 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5541 * These functions are overwritable if your architecture needs its own
5544 struct page * __weak
5545 follow_huge_addr(struct mm_struct *mm, unsigned long address,
5548 return ERR_PTR(-EINVAL);
5551 struct page * __weak
5552 follow_huge_pd(struct vm_area_struct *vma,
5553 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5555 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5559 struct page * __weak
5560 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5561 pmd_t *pmd, int flags)
5563 struct page *page = NULL;
5567 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5568 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5569 (FOLL_PIN | FOLL_GET)))
5573 ptl = pmd_lockptr(mm, pmd);
5576 * make sure that the address range covered by this pmd is not
5577 * unmapped from other threads.
5579 if (!pmd_huge(*pmd))
5581 pte = huge_ptep_get((pte_t *)pmd);
5582 if (pte_present(pte)) {
5583 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5585 * try_grab_page() should always succeed here, because: a) we
5586 * hold the pmd (ptl) lock, and b) we've just checked that the
5587 * huge pmd (head) page is present in the page tables. The ptl
5588 * prevents the head page and tail pages from being rearranged
5589 * in any way. So this page must be available at this point,
5590 * unless the page refcount overflowed:
5592 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5597 if (is_hugetlb_entry_migration(pte)) {
5599 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5603 * hwpoisoned entry is treated as no_page_table in
5604 * follow_page_mask().
5612 struct page * __weak
5613 follow_huge_pud(struct mm_struct *mm, unsigned long address,
5614 pud_t *pud, int flags)
5616 if (flags & (FOLL_GET | FOLL_PIN))
5619 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5622 struct page * __weak
5623 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5625 if (flags & (FOLL_GET | FOLL_PIN))
5628 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5631 bool isolate_huge_page(struct page *page, struct list_head *list)
5635 spin_lock(&hugetlb_lock);
5636 if (!PageHeadHuge(page) ||
5637 !HPageMigratable(page) ||
5638 !get_page_unless_zero(page)) {
5642 ClearHPageMigratable(page);
5643 list_move_tail(&page->lru, list);
5645 spin_unlock(&hugetlb_lock);
5649 void putback_active_hugepage(struct page *page)
5651 spin_lock(&hugetlb_lock);
5652 SetHPageMigratable(page);
5653 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5654 spin_unlock(&hugetlb_lock);
5658 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5660 struct hstate *h = page_hstate(oldpage);
5662 hugetlb_cgroup_migrate(oldpage, newpage);
5663 set_page_owner_migrate_reason(newpage, reason);
5666 * transfer temporary state of the new huge page. This is
5667 * reverse to other transitions because the newpage is going to
5668 * be final while the old one will be freed so it takes over
5669 * the temporary status.
5671 * Also note that we have to transfer the per-node surplus state
5672 * here as well otherwise the global surplus count will not match
5675 if (HPageTemporary(newpage)) {
5676 int old_nid = page_to_nid(oldpage);
5677 int new_nid = page_to_nid(newpage);
5679 SetHPageTemporary(oldpage);
5680 ClearHPageTemporary(newpage);
5682 spin_lock(&hugetlb_lock);
5683 if (h->surplus_huge_pages_node[old_nid]) {
5684 h->surplus_huge_pages_node[old_nid]--;
5685 h->surplus_huge_pages_node[new_nid]++;
5687 spin_unlock(&hugetlb_lock);
5692 static bool cma_reserve_called __initdata;
5694 static int __init cmdline_parse_hugetlb_cma(char *p)
5696 hugetlb_cma_size = memparse(p, &p);
5700 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
5702 void __init hugetlb_cma_reserve(int order)
5704 unsigned long size, reserved, per_node;
5707 cma_reserve_called = true;
5709 if (!hugetlb_cma_size)
5712 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
5713 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5714 (PAGE_SIZE << order) / SZ_1M);
5719 * If 3 GB area is requested on a machine with 4 numa nodes,
5720 * let's allocate 1 GB on first three nodes and ignore the last one.
5722 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
5723 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5724 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
5727 for_each_node_state(nid, N_ONLINE) {
5729 char name[CMA_MAX_NAME];
5731 size = min(per_node, hugetlb_cma_size - reserved);
5732 size = round_up(size, PAGE_SIZE << order);
5734 snprintf(name, sizeof(name), "hugetlb%d", nid);
5735 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5737 &hugetlb_cma[nid], nid);
5739 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
5745 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
5748 if (reserved >= hugetlb_cma_size)
5753 void __init hugetlb_cma_check(void)
5755 if (!hugetlb_cma_size || cma_reserve_called)
5758 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
5761 #endif /* CONFIG_CMA */