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 static inline bool PageHugeFreed(struct page *head)
84 return page_private(head + 4) == -1UL;
87 static inline void SetPageHugeFreed(struct page *head)
89 set_page_private(head + 4, -1UL);
92 static inline void ClearPageHugeFreed(struct page *head)
94 set_page_private(head + 4, 0);
97 /* Forward declaration */
98 static int hugetlb_acct_memory(struct hstate *h, long delta);
100 static inline bool subpool_is_free(struct hugepage_subpool *spool)
104 if (spool->max_hpages != -1)
105 return spool->used_hpages == 0;
106 if (spool->min_hpages != -1)
107 return spool->rsv_hpages == spool->min_hpages;
112 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
114 spin_unlock(&spool->lock);
116 /* If no pages are used, and no other handles to the subpool
117 * remain, give up any reservations based on minimum size and
118 * free the subpool */
119 if (subpool_is_free(spool)) {
120 if (spool->min_hpages != -1)
121 hugetlb_acct_memory(spool->hstate,
127 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
130 struct hugepage_subpool *spool;
132 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
136 spin_lock_init(&spool->lock);
138 spool->max_hpages = max_hpages;
140 spool->min_hpages = min_hpages;
142 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
146 spool->rsv_hpages = min_hpages;
151 void hugepage_put_subpool(struct hugepage_subpool *spool)
153 spin_lock(&spool->lock);
154 BUG_ON(!spool->count);
156 unlock_or_release_subpool(spool);
160 * Subpool accounting for allocating and reserving pages.
161 * Return -ENOMEM if there are not enough resources to satisfy the
162 * request. Otherwise, return the number of pages by which the
163 * global pools must be adjusted (upward). The returned value may
164 * only be different than the passed value (delta) in the case where
165 * a subpool minimum size must be maintained.
167 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
175 spin_lock(&spool->lock);
177 if (spool->max_hpages != -1) { /* maximum size accounting */
178 if ((spool->used_hpages + delta) <= spool->max_hpages)
179 spool->used_hpages += delta;
186 /* minimum size accounting */
187 if (spool->min_hpages != -1 && spool->rsv_hpages) {
188 if (delta > spool->rsv_hpages) {
190 * Asking for more reserves than those already taken on
191 * behalf of subpool. Return difference.
193 ret = delta - spool->rsv_hpages;
194 spool->rsv_hpages = 0;
196 ret = 0; /* reserves already accounted for */
197 spool->rsv_hpages -= delta;
202 spin_unlock(&spool->lock);
207 * Subpool accounting for freeing and unreserving pages.
208 * Return the number of global page reservations that must be dropped.
209 * The return value may only be different than the passed value (delta)
210 * in the case where a subpool minimum size must be maintained.
212 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
220 spin_lock(&spool->lock);
222 if (spool->max_hpages != -1) /* maximum size accounting */
223 spool->used_hpages -= delta;
225 /* minimum size accounting */
226 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
227 if (spool->rsv_hpages + delta <= spool->min_hpages)
230 ret = spool->rsv_hpages + delta - spool->min_hpages;
232 spool->rsv_hpages += delta;
233 if (spool->rsv_hpages > spool->min_hpages)
234 spool->rsv_hpages = spool->min_hpages;
238 * If hugetlbfs_put_super couldn't free spool due to an outstanding
239 * quota reference, free it now.
241 unlock_or_release_subpool(spool);
246 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
248 return HUGETLBFS_SB(inode->i_sb)->spool;
251 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
253 return subpool_inode(file_inode(vma->vm_file));
256 /* Helper that removes a struct file_region from the resv_map cache and returns
259 static struct file_region *
260 get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
262 struct file_region *nrg = NULL;
264 VM_BUG_ON(resv->region_cache_count <= 0);
266 resv->region_cache_count--;
267 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
268 list_del(&nrg->link);
276 static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
277 struct file_region *rg)
279 #ifdef CONFIG_CGROUP_HUGETLB
280 nrg->reservation_counter = rg->reservation_counter;
287 /* Helper that records hugetlb_cgroup uncharge info. */
288 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
290 struct resv_map *resv,
291 struct file_region *nrg)
293 #ifdef CONFIG_CGROUP_HUGETLB
295 nrg->reservation_counter =
296 &h_cg->rsvd_hugepage[hstate_index(h)];
297 nrg->css = &h_cg->css;
298 if (!resv->pages_per_hpage)
299 resv->pages_per_hpage = pages_per_huge_page(h);
300 /* pages_per_hpage should be the same for all entries in
303 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
305 nrg->reservation_counter = NULL;
311 static bool has_same_uncharge_info(struct file_region *rg,
312 struct file_region *org)
314 #ifdef CONFIG_CGROUP_HUGETLB
316 rg->reservation_counter == org->reservation_counter &&
324 static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
326 struct file_region *nrg = NULL, *prg = NULL;
328 prg = list_prev_entry(rg, link);
329 if (&prg->link != &resv->regions && prg->to == rg->from &&
330 has_same_uncharge_info(prg, rg)) {
339 nrg = list_next_entry(rg, link);
340 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
341 has_same_uncharge_info(nrg, rg)) {
342 nrg->from = rg->from;
350 * Must be called with resv->lock held.
352 * Calling this with regions_needed != NULL will count the number of pages
353 * to be added but will not modify the linked list. And regions_needed will
354 * indicate the number of file_regions needed in the cache to carry out to add
355 * the regions for this range.
357 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
358 struct hugetlb_cgroup *h_cg,
359 struct hstate *h, long *regions_needed)
362 struct list_head *head = &resv->regions;
363 long last_accounted_offset = f;
364 struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
369 /* In this loop, we essentially handle an entry for the range
370 * [last_accounted_offset, rg->from), at every iteration, with some
373 list_for_each_entry_safe(rg, trg, head, link) {
374 /* Skip irrelevant regions that start before our range. */
376 /* If this region ends after the last accounted offset,
377 * then we need to update last_accounted_offset.
379 if (rg->to > last_accounted_offset)
380 last_accounted_offset = rg->to;
384 /* When we find a region that starts beyond our range, we've
390 /* Add an entry for last_accounted_offset -> rg->from, and
391 * update last_accounted_offset.
393 if (rg->from > last_accounted_offset) {
394 add += rg->from - last_accounted_offset;
395 if (!regions_needed) {
396 nrg = get_file_region_entry_from_cache(
397 resv, last_accounted_offset, rg->from);
398 record_hugetlb_cgroup_uncharge_info(h_cg, h,
400 list_add(&nrg->link, rg->link.prev);
401 coalesce_file_region(resv, nrg);
403 *regions_needed += 1;
406 last_accounted_offset = rg->to;
409 /* Handle the case where our range extends beyond
410 * last_accounted_offset.
412 if (last_accounted_offset < t) {
413 add += t - last_accounted_offset;
414 if (!regions_needed) {
415 nrg = get_file_region_entry_from_cache(
416 resv, last_accounted_offset, t);
417 record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
418 list_add(&nrg->link, rg->link.prev);
419 coalesce_file_region(resv, nrg);
421 *regions_needed += 1;
428 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
430 static int allocate_file_region_entries(struct resv_map *resv,
432 __must_hold(&resv->lock)
434 struct list_head allocated_regions;
435 int to_allocate = 0, i = 0;
436 struct file_region *trg = NULL, *rg = NULL;
438 VM_BUG_ON(regions_needed < 0);
440 INIT_LIST_HEAD(&allocated_regions);
443 * Check for sufficient descriptors in the cache to accommodate
444 * the number of in progress add operations plus regions_needed.
446 * This is a while loop because when we drop the lock, some other call
447 * to region_add or region_del may have consumed some region_entries,
448 * so we keep looping here until we finally have enough entries for
449 * (adds_in_progress + regions_needed).
451 while (resv->region_cache_count <
452 (resv->adds_in_progress + regions_needed)) {
453 to_allocate = resv->adds_in_progress + regions_needed -
454 resv->region_cache_count;
456 /* At this point, we should have enough entries in the cache
457 * for all the existings adds_in_progress. We should only be
458 * needing to allocate for regions_needed.
460 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
462 spin_unlock(&resv->lock);
463 for (i = 0; i < to_allocate; i++) {
464 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
467 list_add(&trg->link, &allocated_regions);
470 spin_lock(&resv->lock);
472 list_splice(&allocated_regions, &resv->region_cache);
473 resv->region_cache_count += to_allocate;
479 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
487 * Add the huge page range represented by [f, t) to the reserve
488 * map. Regions will be taken from the cache to fill in this range.
489 * Sufficient regions should exist in the cache due to the previous
490 * call to region_chg with the same range, but in some cases the cache will not
491 * have sufficient entries due to races with other code doing region_add or
492 * region_del. The extra needed entries will be allocated.
494 * regions_needed is the out value provided by a previous call to region_chg.
496 * Return the number of new huge pages added to the map. This number is greater
497 * than or equal to zero. If file_region entries needed to be allocated for
498 * this operation and we were not able to allocate, it returns -ENOMEM.
499 * region_add of regions of length 1 never allocate file_regions and cannot
500 * fail; region_chg will always allocate at least 1 entry and a region_add for
501 * 1 page will only require at most 1 entry.
503 static long region_add(struct resv_map *resv, long f, long t,
504 long in_regions_needed, struct hstate *h,
505 struct hugetlb_cgroup *h_cg)
507 long add = 0, actual_regions_needed = 0;
509 spin_lock(&resv->lock);
512 /* Count how many regions are actually needed to execute this add. */
513 add_reservation_in_range(resv, f, t, NULL, NULL,
514 &actual_regions_needed);
517 * Check for sufficient descriptors in the cache to accommodate
518 * this add operation. Note that actual_regions_needed may be greater
519 * than in_regions_needed, as the resv_map may have been modified since
520 * the region_chg call. In this case, we need to make sure that we
521 * allocate extra entries, such that we have enough for all the
522 * existing adds_in_progress, plus the excess needed for this
525 if (actual_regions_needed > in_regions_needed &&
526 resv->region_cache_count <
527 resv->adds_in_progress +
528 (actual_regions_needed - in_regions_needed)) {
529 /* region_add operation of range 1 should never need to
530 * allocate file_region entries.
532 VM_BUG_ON(t - f <= 1);
534 if (allocate_file_region_entries(
535 resv, actual_regions_needed - in_regions_needed)) {
542 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
544 resv->adds_in_progress -= in_regions_needed;
546 spin_unlock(&resv->lock);
552 * Examine the existing reserve map and determine how many
553 * huge pages in the specified range [f, t) are NOT currently
554 * represented. This routine is called before a subsequent
555 * call to region_add that will actually modify the reserve
556 * map to add the specified range [f, t). region_chg does
557 * not change the number of huge pages represented by the
558 * map. A number of new file_region structures is added to the cache as a
559 * placeholder, for the subsequent region_add call to use. At least 1
560 * file_region structure is added.
562 * out_regions_needed is the number of regions added to the
563 * resv->adds_in_progress. This value needs to be provided to a follow up call
564 * to region_add or region_abort for proper accounting.
566 * Returns the number of huge pages that need to be added to the existing
567 * reservation map for the range [f, t). This number is greater or equal to
568 * zero. -ENOMEM is returned if a new file_region structure or cache entry
569 * is needed and can not be allocated.
571 static long region_chg(struct resv_map *resv, long f, long t,
572 long *out_regions_needed)
576 spin_lock(&resv->lock);
578 /* Count how many hugepages in this range are NOT represented. */
579 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
582 if (*out_regions_needed == 0)
583 *out_regions_needed = 1;
585 if (allocate_file_region_entries(resv, *out_regions_needed))
588 resv->adds_in_progress += *out_regions_needed;
590 spin_unlock(&resv->lock);
595 * Abort the in progress add operation. The adds_in_progress field
596 * of the resv_map keeps track of the operations in progress between
597 * calls to region_chg and region_add. Operations are sometimes
598 * aborted after the call to region_chg. In such cases, region_abort
599 * is called to decrement the adds_in_progress counter. regions_needed
600 * is the value returned by the region_chg call, it is used to decrement
601 * the adds_in_progress counter.
603 * NOTE: The range arguments [f, t) are not needed or used in this
604 * routine. They are kept to make reading the calling code easier as
605 * arguments will match the associated region_chg call.
607 static void region_abort(struct resv_map *resv, long f, long t,
610 spin_lock(&resv->lock);
611 VM_BUG_ON(!resv->region_cache_count);
612 resv->adds_in_progress -= regions_needed;
613 spin_unlock(&resv->lock);
617 * Delete the specified range [f, t) from the reserve map. If the
618 * t parameter is LONG_MAX, this indicates that ALL regions after f
619 * should be deleted. Locate the regions which intersect [f, t)
620 * and either trim, delete or split the existing regions.
622 * Returns the number of huge pages deleted from the reserve map.
623 * In the normal case, the return value is zero or more. In the
624 * case where a region must be split, a new region descriptor must
625 * be allocated. If the allocation fails, -ENOMEM will be returned.
626 * NOTE: If the parameter t == LONG_MAX, then we will never split
627 * a region and possibly return -ENOMEM. Callers specifying
628 * t == LONG_MAX do not need to check for -ENOMEM error.
630 static long region_del(struct resv_map *resv, long f, long t)
632 struct list_head *head = &resv->regions;
633 struct file_region *rg, *trg;
634 struct file_region *nrg = NULL;
638 spin_lock(&resv->lock);
639 list_for_each_entry_safe(rg, trg, head, link) {
641 * Skip regions before the range to be deleted. file_region
642 * ranges are normally of the form [from, to). However, there
643 * may be a "placeholder" entry in the map which is of the form
644 * (from, to) with from == to. Check for placeholder entries
645 * at the beginning of the range to be deleted.
647 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
653 if (f > rg->from && t < rg->to) { /* Must split region */
655 * Check for an entry in the cache before dropping
656 * lock and attempting allocation.
659 resv->region_cache_count > resv->adds_in_progress) {
660 nrg = list_first_entry(&resv->region_cache,
663 list_del(&nrg->link);
664 resv->region_cache_count--;
668 spin_unlock(&resv->lock);
669 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
676 hugetlb_cgroup_uncharge_file_region(
679 /* New entry for end of split region */
683 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
685 INIT_LIST_HEAD(&nrg->link);
687 /* Original entry is trimmed */
690 list_add(&nrg->link, &rg->link);
695 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
696 del += rg->to - rg->from;
697 hugetlb_cgroup_uncharge_file_region(resv, rg,
704 if (f <= rg->from) { /* Trim beginning of region */
705 hugetlb_cgroup_uncharge_file_region(resv, rg,
710 } else { /* Trim end of region */
711 hugetlb_cgroup_uncharge_file_region(resv, rg,
719 spin_unlock(&resv->lock);
725 * A rare out of memory error was encountered which prevented removal of
726 * the reserve map region for a page. The huge page itself was free'ed
727 * and removed from the page cache. This routine will adjust the subpool
728 * usage count, and the global reserve count if needed. By incrementing
729 * these counts, the reserve map entry which could not be deleted will
730 * appear as a "reserved" entry instead of simply dangling with incorrect
733 void hugetlb_fix_reserve_counts(struct inode *inode)
735 struct hugepage_subpool *spool = subpool_inode(inode);
738 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
740 struct hstate *h = hstate_inode(inode);
742 hugetlb_acct_memory(h, 1);
747 * Count and return the number of huge pages in the reserve map
748 * that intersect with the range [f, t).
750 static long region_count(struct resv_map *resv, long f, long t)
752 struct list_head *head = &resv->regions;
753 struct file_region *rg;
756 spin_lock(&resv->lock);
757 /* Locate each segment we overlap with, and count that overlap. */
758 list_for_each_entry(rg, head, link) {
767 seg_from = max(rg->from, f);
768 seg_to = min(rg->to, t);
770 chg += seg_to - seg_from;
772 spin_unlock(&resv->lock);
778 * Convert the address within this vma to the page offset within
779 * the mapping, in pagecache page units; huge pages here.
781 static pgoff_t vma_hugecache_offset(struct hstate *h,
782 struct vm_area_struct *vma, unsigned long address)
784 return ((address - vma->vm_start) >> huge_page_shift(h)) +
785 (vma->vm_pgoff >> huge_page_order(h));
788 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
789 unsigned long address)
791 return vma_hugecache_offset(hstate_vma(vma), vma, address);
793 EXPORT_SYMBOL_GPL(linear_hugepage_index);
796 * Return the size of the pages allocated when backing a VMA. In the majority
797 * cases this will be same size as used by the page table entries.
799 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
801 if (vma->vm_ops && vma->vm_ops->pagesize)
802 return vma->vm_ops->pagesize(vma);
805 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
808 * Return the page size being used by the MMU to back a VMA. In the majority
809 * of cases, the page size used by the kernel matches the MMU size. On
810 * architectures where it differs, an architecture-specific 'strong'
811 * version of this symbol is required.
813 __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
815 return vma_kernel_pagesize(vma);
819 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
820 * bits of the reservation map pointer, which are always clear due to
823 #define HPAGE_RESV_OWNER (1UL << 0)
824 #define HPAGE_RESV_UNMAPPED (1UL << 1)
825 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
828 * These helpers are used to track how many pages are reserved for
829 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
830 * is guaranteed to have their future faults succeed.
832 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
833 * the reserve counters are updated with the hugetlb_lock held. It is safe
834 * to reset the VMA at fork() time as it is not in use yet and there is no
835 * chance of the global counters getting corrupted as a result of the values.
837 * The private mapping reservation is represented in a subtly different
838 * manner to a shared mapping. A shared mapping has a region map associated
839 * with the underlying file, this region map represents the backing file
840 * pages which have ever had a reservation assigned which this persists even
841 * after the page is instantiated. A private mapping has a region map
842 * associated with the original mmap which is attached to all VMAs which
843 * reference it, this region map represents those offsets which have consumed
844 * reservation ie. where pages have been instantiated.
846 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
848 return (unsigned long)vma->vm_private_data;
851 static void set_vma_private_data(struct vm_area_struct *vma,
854 vma->vm_private_data = (void *)value;
858 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
859 struct hugetlb_cgroup *h_cg,
862 #ifdef CONFIG_CGROUP_HUGETLB
864 resv_map->reservation_counter = NULL;
865 resv_map->pages_per_hpage = 0;
866 resv_map->css = NULL;
868 resv_map->reservation_counter =
869 &h_cg->rsvd_hugepage[hstate_index(h)];
870 resv_map->pages_per_hpage = pages_per_huge_page(h);
871 resv_map->css = &h_cg->css;
876 struct resv_map *resv_map_alloc(void)
878 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
879 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
881 if (!resv_map || !rg) {
887 kref_init(&resv_map->refs);
888 spin_lock_init(&resv_map->lock);
889 INIT_LIST_HEAD(&resv_map->regions);
891 resv_map->adds_in_progress = 0;
893 * Initialize these to 0. On shared mappings, 0's here indicate these
894 * fields don't do cgroup accounting. On private mappings, these will be
895 * re-initialized to the proper values, to indicate that hugetlb cgroup
896 * reservations are to be un-charged from here.
898 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
900 INIT_LIST_HEAD(&resv_map->region_cache);
901 list_add(&rg->link, &resv_map->region_cache);
902 resv_map->region_cache_count = 1;
907 void resv_map_release(struct kref *ref)
909 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
910 struct list_head *head = &resv_map->region_cache;
911 struct file_region *rg, *trg;
913 /* Clear out any active regions before we release the map. */
914 region_del(resv_map, 0, LONG_MAX);
916 /* ... and any entries left in the cache */
917 list_for_each_entry_safe(rg, trg, head, link) {
922 VM_BUG_ON(resv_map->adds_in_progress);
927 static inline struct resv_map *inode_resv_map(struct inode *inode)
930 * At inode evict time, i_mapping may not point to the original
931 * address space within the inode. This original address space
932 * contains the pointer to the resv_map. So, always use the
933 * address space embedded within the inode.
934 * The VERY common case is inode->mapping == &inode->i_data but,
935 * this may not be true for device special inodes.
937 return (struct resv_map *)(&inode->i_data)->private_data;
940 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
942 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
943 if (vma->vm_flags & VM_MAYSHARE) {
944 struct address_space *mapping = vma->vm_file->f_mapping;
945 struct inode *inode = mapping->host;
947 return inode_resv_map(inode);
950 return (struct resv_map *)(get_vma_private_data(vma) &
955 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
957 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
958 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
960 set_vma_private_data(vma, (get_vma_private_data(vma) &
961 HPAGE_RESV_MASK) | (unsigned long)map);
964 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
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) | flags);
972 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
974 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
976 return (get_vma_private_data(vma) & flag) != 0;
979 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
980 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
982 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
983 if (!(vma->vm_flags & VM_MAYSHARE))
984 vma->vm_private_data = (void *)0;
987 /* Returns true if the VMA has associated reserve pages */
988 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
990 if (vma->vm_flags & VM_NORESERVE) {
992 * This address is already reserved by other process(chg == 0),
993 * so, we should decrement reserved count. Without decrementing,
994 * reserve count remains after releasing inode, because this
995 * allocated page will go into page cache and is regarded as
996 * coming from reserved pool in releasing step. Currently, we
997 * don't have any other solution to deal with this situation
998 * properly, so add work-around here.
1000 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1006 /* Shared mappings always use reserves */
1007 if (vma->vm_flags & VM_MAYSHARE) {
1009 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1010 * be a region map for all pages. The only situation where
1011 * there is no region map is if a hole was punched via
1012 * fallocate. In this case, there really are no reserves to
1013 * use. This situation is indicated if chg != 0.
1022 * Only the process that called mmap() has reserves for
1025 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1027 * Like the shared case above, a hole punch or truncate
1028 * could have been performed on the private mapping.
1029 * Examine the value of chg to determine if reserves
1030 * actually exist or were previously consumed.
1031 * Very Subtle - The value of chg comes from a previous
1032 * call to vma_needs_reserves(). The reserve map for
1033 * private mappings has different (opposite) semantics
1034 * than that of shared mappings. vma_needs_reserves()
1035 * has already taken this difference in semantics into
1036 * account. Therefore, the meaning of chg is the same
1037 * as in the shared case above. Code could easily be
1038 * combined, but keeping it separate draws attention to
1039 * subtle differences.
1050 static void enqueue_huge_page(struct hstate *h, struct page *page)
1052 int nid = page_to_nid(page);
1053 list_move(&page->lru, &h->hugepage_freelists[nid]);
1054 h->free_huge_pages++;
1055 h->free_huge_pages_node[nid]++;
1056 SetPageHugeFreed(page);
1059 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1062 bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
1064 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1065 if (nocma && is_migrate_cma_page(page))
1068 if (PageHWPoison(page))
1071 list_move(&page->lru, &h->hugepage_activelist);
1072 set_page_refcounted(page);
1073 ClearPageHugeFreed(page);
1074 h->free_huge_pages--;
1075 h->free_huge_pages_node[nid]--;
1082 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1085 unsigned int cpuset_mems_cookie;
1086 struct zonelist *zonelist;
1089 int node = NUMA_NO_NODE;
1091 zonelist = node_zonelist(nid, gfp_mask);
1094 cpuset_mems_cookie = read_mems_allowed_begin();
1095 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1098 if (!cpuset_zone_allowed(zone, gfp_mask))
1101 * no need to ask again on the same node. Pool is node rather than
1104 if (zone_to_nid(zone) == node)
1106 node = zone_to_nid(zone);
1108 page = dequeue_huge_page_node_exact(h, node);
1112 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1118 static struct page *dequeue_huge_page_vma(struct hstate *h,
1119 struct vm_area_struct *vma,
1120 unsigned long address, int avoid_reserve,
1124 struct mempolicy *mpol;
1126 nodemask_t *nodemask;
1130 * A child process with MAP_PRIVATE mappings created by their parent
1131 * have no page reserves. This check ensures that reservations are
1132 * not "stolen". The child may still get SIGKILLed
1134 if (!vma_has_reserves(vma, chg) &&
1135 h->free_huge_pages - h->resv_huge_pages == 0)
1138 /* If reserves cannot be used, ensure enough pages are in the pool */
1139 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1142 gfp_mask = htlb_alloc_mask(h);
1143 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1144 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1145 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1146 SetHPageRestoreReserve(page);
1147 h->resv_huge_pages--;
1150 mpol_cond_put(mpol);
1158 * common helper functions for hstate_next_node_to_{alloc|free}.
1159 * We may have allocated or freed a huge page based on a different
1160 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1161 * be outside of *nodes_allowed. Ensure that we use an allowed
1162 * node for alloc or free.
1164 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1166 nid = next_node_in(nid, *nodes_allowed);
1167 VM_BUG_ON(nid >= MAX_NUMNODES);
1172 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1174 if (!node_isset(nid, *nodes_allowed))
1175 nid = next_node_allowed(nid, nodes_allowed);
1180 * returns the previously saved node ["this node"] from which to
1181 * allocate a persistent huge page for the pool and advance the
1182 * next node from which to allocate, handling wrap at end of node
1185 static int hstate_next_node_to_alloc(struct hstate *h,
1186 nodemask_t *nodes_allowed)
1190 VM_BUG_ON(!nodes_allowed);
1192 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1193 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1199 * helper for free_pool_huge_page() - return the previously saved
1200 * node ["this node"] from which to free a huge page. Advance the
1201 * next node id whether or not we find a free huge page to free so
1202 * that the next attempt to free addresses the next node.
1204 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1208 VM_BUG_ON(!nodes_allowed);
1210 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1211 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1216 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1217 for (nr_nodes = nodes_weight(*mask); \
1219 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1222 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1223 for (nr_nodes = nodes_weight(*mask); \
1225 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1228 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1229 static void destroy_compound_gigantic_page(struct page *page,
1233 int nr_pages = 1 << order;
1234 struct page *p = page + 1;
1236 atomic_set(compound_mapcount_ptr(page), 0);
1237 atomic_set(compound_pincount_ptr(page), 0);
1239 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1240 clear_compound_head(p);
1241 set_page_refcounted(p);
1244 set_compound_order(page, 0);
1245 page[1].compound_nr = 0;
1246 __ClearPageHead(page);
1249 static void free_gigantic_page(struct page *page, unsigned int order)
1252 * If the page isn't allocated using the cma allocator,
1253 * cma_release() returns false.
1256 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1260 free_contig_range(page_to_pfn(page), 1 << order);
1263 #ifdef CONFIG_CONTIG_ALLOC
1264 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1265 int nid, nodemask_t *nodemask)
1267 unsigned long nr_pages = 1UL << huge_page_order(h);
1268 if (nid == NUMA_NO_NODE)
1269 nid = numa_mem_id();
1276 if (hugetlb_cma[nid]) {
1277 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1278 huge_page_order(h), true);
1283 if (!(gfp_mask & __GFP_THISNODE)) {
1284 for_each_node_mask(node, *nodemask) {
1285 if (node == nid || !hugetlb_cma[node])
1288 page = cma_alloc(hugetlb_cma[node], nr_pages,
1289 huge_page_order(h), true);
1297 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1300 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1301 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1302 #else /* !CONFIG_CONTIG_ALLOC */
1303 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1304 int nid, nodemask_t *nodemask)
1308 #endif /* CONFIG_CONTIG_ALLOC */
1310 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1311 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1312 int nid, nodemask_t *nodemask)
1316 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1317 static inline void destroy_compound_gigantic_page(struct page *page,
1318 unsigned int order) { }
1321 static void update_and_free_page(struct hstate *h, struct page *page)
1324 struct page *subpage = page;
1326 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1330 h->nr_huge_pages_node[page_to_nid(page)]--;
1331 for (i = 0; i < pages_per_huge_page(h);
1332 i++, subpage = mem_map_next(subpage, page, i)) {
1333 subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1334 1 << PG_referenced | 1 << PG_dirty |
1335 1 << PG_active | 1 << PG_private |
1338 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1339 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1340 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1341 set_page_refcounted(page);
1342 if (hstate_is_gigantic(h)) {
1344 * Temporarily drop the hugetlb_lock, because
1345 * we might block in free_gigantic_page().
1347 spin_unlock(&hugetlb_lock);
1348 destroy_compound_gigantic_page(page, huge_page_order(h));
1349 free_gigantic_page(page, huge_page_order(h));
1350 spin_lock(&hugetlb_lock);
1352 __free_pages(page, huge_page_order(h));
1356 struct hstate *size_to_hstate(unsigned long size)
1360 for_each_hstate(h) {
1361 if (huge_page_size(h) == size)
1368 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1369 * to hstate->hugepage_activelist.)
1371 * This function can be called for tail pages, but never returns true for them.
1373 bool page_huge_active(struct page *page)
1375 return PageHeadHuge(page) && PagePrivate(&page[1]);
1378 /* never called for tail page */
1379 void set_page_huge_active(struct page *page)
1381 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1382 SetPagePrivate(&page[1]);
1385 static void clear_page_huge_active(struct page *page)
1387 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1388 ClearPagePrivate(&page[1]);
1392 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1395 static inline bool PageHugeTemporary(struct page *page)
1397 if (!PageHuge(page))
1400 return (unsigned long)page[2].mapping == -1U;
1403 static inline void SetPageHugeTemporary(struct page *page)
1405 page[2].mapping = (void *)-1U;
1408 static inline void ClearPageHugeTemporary(struct page *page)
1410 page[2].mapping = NULL;
1413 static void __free_huge_page(struct page *page)
1416 * Can't pass hstate in here because it is called from the
1417 * compound page destructor.
1419 struct hstate *h = page_hstate(page);
1420 int nid = page_to_nid(page);
1421 struct hugepage_subpool *spool = hugetlb_page_subpool(page);
1422 bool restore_reserve;
1424 VM_BUG_ON_PAGE(page_count(page), page);
1425 VM_BUG_ON_PAGE(page_mapcount(page), page);
1427 hugetlb_set_page_subpool(page, NULL);
1428 page->mapping = NULL;
1429 restore_reserve = HPageRestoreReserve(page);
1430 ClearHPageRestoreReserve(page);
1433 * If HPageRestoreReserve was set on page, page allocation consumed a
1434 * reservation. If the page was associated with a subpool, there
1435 * would have been a page reserved in the subpool before allocation
1436 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1437 * reservation, do not call hugepage_subpool_put_pages() as this will
1438 * remove the reserved page from the subpool.
1440 if (!restore_reserve) {
1442 * A return code of zero implies that the subpool will be
1443 * under its minimum size if the reservation is not restored
1444 * after page is free. Therefore, force restore_reserve
1447 if (hugepage_subpool_put_pages(spool, 1) == 0)
1448 restore_reserve = true;
1451 spin_lock(&hugetlb_lock);
1452 clear_page_huge_active(page);
1453 hugetlb_cgroup_uncharge_page(hstate_index(h),
1454 pages_per_huge_page(h), page);
1455 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1456 pages_per_huge_page(h), page);
1457 if (restore_reserve)
1458 h->resv_huge_pages++;
1460 if (PageHugeTemporary(page)) {
1461 list_del(&page->lru);
1462 ClearPageHugeTemporary(page);
1463 update_and_free_page(h, page);
1464 } else if (h->surplus_huge_pages_node[nid]) {
1465 /* remove the page from active list */
1466 list_del(&page->lru);
1467 update_and_free_page(h, page);
1468 h->surplus_huge_pages--;
1469 h->surplus_huge_pages_node[nid]--;
1471 arch_clear_hugepage_flags(page);
1472 enqueue_huge_page(h, page);
1474 spin_unlock(&hugetlb_lock);
1478 * As free_huge_page() can be called from a non-task context, we have
1479 * to defer the actual freeing in a workqueue to prevent potential
1480 * hugetlb_lock deadlock.
1482 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1483 * be freed and frees them one-by-one. As the page->mapping pointer is
1484 * going to be cleared in __free_huge_page() anyway, it is reused as the
1485 * llist_node structure of a lockless linked list of huge pages to be freed.
1487 static LLIST_HEAD(hpage_freelist);
1489 static void free_hpage_workfn(struct work_struct *work)
1491 struct llist_node *node;
1494 node = llist_del_all(&hpage_freelist);
1497 page = container_of((struct address_space **)node,
1498 struct page, mapping);
1500 __free_huge_page(page);
1503 static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1505 void free_huge_page(struct page *page)
1508 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1512 * Only call schedule_work() if hpage_freelist is previously
1513 * empty. Otherwise, schedule_work() had been called but the
1514 * workfn hasn't retrieved the list yet.
1516 if (llist_add((struct llist_node *)&page->mapping,
1518 schedule_work(&free_hpage_work);
1522 __free_huge_page(page);
1525 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1527 INIT_LIST_HEAD(&page->lru);
1528 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1529 set_hugetlb_cgroup(page, NULL);
1530 set_hugetlb_cgroup_rsvd(page, NULL);
1531 spin_lock(&hugetlb_lock);
1533 h->nr_huge_pages_node[nid]++;
1534 ClearPageHugeFreed(page);
1535 spin_unlock(&hugetlb_lock);
1538 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1541 int nr_pages = 1 << order;
1542 struct page *p = page + 1;
1544 /* we rely on prep_new_huge_page to set the destructor */
1545 set_compound_order(page, order);
1546 __ClearPageReserved(page);
1547 __SetPageHead(page);
1548 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1550 * For gigantic hugepages allocated through bootmem at
1551 * boot, it's safer to be consistent with the not-gigantic
1552 * hugepages and clear the PG_reserved bit from all tail pages
1553 * too. Otherwise drivers using get_user_pages() to access tail
1554 * pages may get the reference counting wrong if they see
1555 * PG_reserved set on a tail page (despite the head page not
1556 * having PG_reserved set). Enforcing this consistency between
1557 * head and tail pages allows drivers to optimize away a check
1558 * on the head page when they need know if put_page() is needed
1559 * after get_user_pages().
1561 __ClearPageReserved(p);
1562 set_page_count(p, 0);
1563 set_compound_head(p, page);
1565 atomic_set(compound_mapcount_ptr(page), -1);
1566 atomic_set(compound_pincount_ptr(page), 0);
1570 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1571 * transparent huge pages. See the PageTransHuge() documentation for more
1574 int PageHuge(struct page *page)
1576 if (!PageCompound(page))
1579 page = compound_head(page);
1580 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1582 EXPORT_SYMBOL_GPL(PageHuge);
1585 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1586 * normal or transparent huge pages.
1588 int PageHeadHuge(struct page *page_head)
1590 if (!PageHead(page_head))
1593 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1597 * Find and lock address space (mapping) in write mode.
1599 * Upon entry, the page is locked which means that page_mapping() is
1600 * stable. Due to locking order, we can only trylock_write. If we can
1601 * not get the lock, simply return NULL to caller.
1603 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1605 struct address_space *mapping = page_mapping(hpage);
1610 if (i_mmap_trylock_write(mapping))
1616 pgoff_t __basepage_index(struct page *page)
1618 struct page *page_head = compound_head(page);
1619 pgoff_t index = page_index(page_head);
1620 unsigned long compound_idx;
1622 if (!PageHuge(page_head))
1623 return page_index(page);
1625 if (compound_order(page_head) >= MAX_ORDER)
1626 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1628 compound_idx = page - page_head;
1630 return (index << compound_order(page_head)) + compound_idx;
1633 static struct page *alloc_buddy_huge_page(struct hstate *h,
1634 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1635 nodemask_t *node_alloc_noretry)
1637 int order = huge_page_order(h);
1639 bool alloc_try_hard = true;
1642 * By default we always try hard to allocate the page with
1643 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1644 * a loop (to adjust global huge page counts) and previous allocation
1645 * failed, do not continue to try hard on the same node. Use the
1646 * node_alloc_noretry bitmap to manage this state information.
1648 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1649 alloc_try_hard = false;
1650 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1652 gfp_mask |= __GFP_RETRY_MAYFAIL;
1653 if (nid == NUMA_NO_NODE)
1654 nid = numa_mem_id();
1655 page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
1657 __count_vm_event(HTLB_BUDDY_PGALLOC);
1659 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1662 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1663 * indicates an overall state change. Clear bit so that we resume
1664 * normal 'try hard' allocations.
1666 if (node_alloc_noretry && page && !alloc_try_hard)
1667 node_clear(nid, *node_alloc_noretry);
1670 * If we tried hard to get a page but failed, set bit so that
1671 * subsequent attempts will not try as hard until there is an
1672 * overall state change.
1674 if (node_alloc_noretry && !page && alloc_try_hard)
1675 node_set(nid, *node_alloc_noretry);
1681 * Common helper to allocate a fresh hugetlb page. All specific allocators
1682 * should use this function to get new hugetlb pages
1684 static struct page *alloc_fresh_huge_page(struct hstate *h,
1685 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1686 nodemask_t *node_alloc_noretry)
1690 if (hstate_is_gigantic(h))
1691 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1693 page = alloc_buddy_huge_page(h, gfp_mask,
1694 nid, nmask, node_alloc_noretry);
1698 if (hstate_is_gigantic(h))
1699 prep_compound_gigantic_page(page, huge_page_order(h));
1700 prep_new_huge_page(h, page, page_to_nid(page));
1706 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1709 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1710 nodemask_t *node_alloc_noretry)
1714 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1716 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1717 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1718 node_alloc_noretry);
1726 put_page(page); /* free it into the hugepage allocator */
1732 * Free huge page from pool from next node to free.
1733 * Attempt to keep persistent huge pages more or less
1734 * balanced over allowed nodes.
1735 * Called with hugetlb_lock locked.
1737 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1743 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1745 * If we're returning unused surplus pages, only examine
1746 * nodes with surplus pages.
1748 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1749 !list_empty(&h->hugepage_freelists[node])) {
1751 list_entry(h->hugepage_freelists[node].next,
1753 list_del(&page->lru);
1754 h->free_huge_pages--;
1755 h->free_huge_pages_node[node]--;
1757 h->surplus_huge_pages--;
1758 h->surplus_huge_pages_node[node]--;
1760 update_and_free_page(h, page);
1770 * Dissolve a given free hugepage into free buddy pages. This function does
1771 * nothing for in-use hugepages and non-hugepages.
1772 * This function returns values like below:
1774 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1775 * (allocated or reserved.)
1776 * 0: successfully dissolved free hugepages or the page is not a
1777 * hugepage (considered as already dissolved)
1779 int dissolve_free_huge_page(struct page *page)
1784 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1785 if (!PageHuge(page))
1788 spin_lock(&hugetlb_lock);
1789 if (!PageHuge(page)) {
1794 if (!page_count(page)) {
1795 struct page *head = compound_head(page);
1796 struct hstate *h = page_hstate(head);
1797 int nid = page_to_nid(head);
1798 if (h->free_huge_pages - h->resv_huge_pages == 0)
1802 * We should make sure that the page is already on the free list
1803 * when it is dissolved.
1805 if (unlikely(!PageHugeFreed(head))) {
1806 spin_unlock(&hugetlb_lock);
1810 * Theoretically, we should return -EBUSY when we
1811 * encounter this race. In fact, we have a chance
1812 * to successfully dissolve the page if we do a
1813 * retry. Because the race window is quite small.
1814 * If we seize this opportunity, it is an optimization
1815 * for increasing the success rate of dissolving page.
1821 * Move PageHWPoison flag from head page to the raw error page,
1822 * which makes any subpages rather than the error page reusable.
1824 if (PageHWPoison(head) && page != head) {
1825 SetPageHWPoison(page);
1826 ClearPageHWPoison(head);
1828 list_del(&head->lru);
1829 h->free_huge_pages--;
1830 h->free_huge_pages_node[nid]--;
1831 h->max_huge_pages--;
1832 update_and_free_page(h, head);
1836 spin_unlock(&hugetlb_lock);
1841 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1842 * make specified memory blocks removable from the system.
1843 * Note that this will dissolve a free gigantic hugepage completely, if any
1844 * part of it lies within the given range.
1845 * Also note that if dissolve_free_huge_page() returns with an error, all
1846 * free hugepages that were dissolved before that error are lost.
1848 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1854 if (!hugepages_supported())
1857 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1858 page = pfn_to_page(pfn);
1859 rc = dissolve_free_huge_page(page);
1868 * Allocates a fresh surplus page from the page allocator.
1870 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1871 int nid, nodemask_t *nmask)
1873 struct page *page = NULL;
1875 if (hstate_is_gigantic(h))
1878 spin_lock(&hugetlb_lock);
1879 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1881 spin_unlock(&hugetlb_lock);
1883 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1887 spin_lock(&hugetlb_lock);
1889 * We could have raced with the pool size change.
1890 * Double check that and simply deallocate the new page
1891 * if we would end up overcommiting the surpluses. Abuse
1892 * temporary page to workaround the nasty free_huge_page
1895 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1896 SetPageHugeTemporary(page);
1897 spin_unlock(&hugetlb_lock);
1901 h->surplus_huge_pages++;
1902 h->surplus_huge_pages_node[page_to_nid(page)]++;
1906 spin_unlock(&hugetlb_lock);
1911 static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1912 int nid, nodemask_t *nmask)
1916 if (hstate_is_gigantic(h))
1919 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1924 * We do not account these pages as surplus because they are only
1925 * temporary and will be released properly on the last reference
1927 SetPageHugeTemporary(page);
1933 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1936 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1937 struct vm_area_struct *vma, unsigned long addr)
1940 struct mempolicy *mpol;
1941 gfp_t gfp_mask = htlb_alloc_mask(h);
1943 nodemask_t *nodemask;
1945 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1946 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1947 mpol_cond_put(mpol);
1952 /* page migration callback function */
1953 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1954 nodemask_t *nmask, gfp_t gfp_mask)
1956 spin_lock(&hugetlb_lock);
1957 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1960 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1962 spin_unlock(&hugetlb_lock);
1966 spin_unlock(&hugetlb_lock);
1968 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1971 /* mempolicy aware migration callback */
1972 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
1973 unsigned long address)
1975 struct mempolicy *mpol;
1976 nodemask_t *nodemask;
1981 gfp_mask = htlb_alloc_mask(h);
1982 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1983 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
1984 mpol_cond_put(mpol);
1990 * Increase the hugetlb pool such that it can accommodate a reservation
1993 static int gather_surplus_pages(struct hstate *h, long delta)
1994 __must_hold(&hugetlb_lock)
1996 struct list_head surplus_list;
1997 struct page *page, *tmp;
2000 long needed, allocated;
2001 bool alloc_ok = true;
2003 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2005 h->resv_huge_pages += delta;
2010 INIT_LIST_HEAD(&surplus_list);
2014 spin_unlock(&hugetlb_lock);
2015 for (i = 0; i < needed; i++) {
2016 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2017 NUMA_NO_NODE, NULL);
2022 list_add(&page->lru, &surplus_list);
2028 * After retaking hugetlb_lock, we need to recalculate 'needed'
2029 * because either resv_huge_pages or free_huge_pages may have changed.
2031 spin_lock(&hugetlb_lock);
2032 needed = (h->resv_huge_pages + delta) -
2033 (h->free_huge_pages + allocated);
2038 * We were not able to allocate enough pages to
2039 * satisfy the entire reservation so we free what
2040 * we've allocated so far.
2045 * The surplus_list now contains _at_least_ the number of extra pages
2046 * needed to accommodate the reservation. Add the appropriate number
2047 * of pages to the hugetlb pool and free the extras back to the buddy
2048 * allocator. Commit the entire reservation here to prevent another
2049 * process from stealing the pages as they are added to the pool but
2050 * before they are reserved.
2052 needed += allocated;
2053 h->resv_huge_pages += delta;
2056 /* Free the needed pages to the hugetlb pool */
2057 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2063 * This page is now managed by the hugetlb allocator and has
2064 * no users -- drop the buddy allocator's reference.
2066 zeroed = put_page_testzero(page);
2067 VM_BUG_ON_PAGE(!zeroed, page);
2068 enqueue_huge_page(h, page);
2071 spin_unlock(&hugetlb_lock);
2073 /* Free unnecessary surplus pages to the buddy allocator */
2074 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2076 spin_lock(&hugetlb_lock);
2082 * This routine has two main purposes:
2083 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2084 * in unused_resv_pages. This corresponds to the prior adjustments made
2085 * to the associated reservation map.
2086 * 2) Free any unused surplus pages that may have been allocated to satisfy
2087 * the reservation. As many as unused_resv_pages may be freed.
2089 * Called with hugetlb_lock held. However, the lock could be dropped (and
2090 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2091 * we must make sure nobody else can claim pages we are in the process of
2092 * freeing. Do this by ensuring resv_huge_page always is greater than the
2093 * number of huge pages we plan to free when dropping the lock.
2095 static void return_unused_surplus_pages(struct hstate *h,
2096 unsigned long unused_resv_pages)
2098 unsigned long nr_pages;
2100 /* Cannot return gigantic pages currently */
2101 if (hstate_is_gigantic(h))
2105 * Part (or even all) of the reservation could have been backed
2106 * by pre-allocated pages. Only free surplus pages.
2108 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2111 * We want to release as many surplus pages as possible, spread
2112 * evenly across all nodes with memory. Iterate across these nodes
2113 * until we can no longer free unreserved surplus pages. This occurs
2114 * when the nodes with surplus pages have no free pages.
2115 * free_pool_huge_page() will balance the freed pages across the
2116 * on-line nodes with memory and will handle the hstate accounting.
2118 * Note that we decrement resv_huge_pages as we free the pages. If
2119 * we drop the lock, resv_huge_pages will still be sufficiently large
2120 * to cover subsequent pages we may free.
2122 while (nr_pages--) {
2123 h->resv_huge_pages--;
2124 unused_resv_pages--;
2125 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2127 cond_resched_lock(&hugetlb_lock);
2131 /* Fully uncommit the reservation */
2132 h->resv_huge_pages -= unused_resv_pages;
2137 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2138 * are used by the huge page allocation routines to manage reservations.
2140 * vma_needs_reservation is called to determine if the huge page at addr
2141 * within the vma has an associated reservation. If a reservation is
2142 * needed, the value 1 is returned. The caller is then responsible for
2143 * managing the global reservation and subpool usage counts. After
2144 * the huge page has been allocated, vma_commit_reservation is called
2145 * to add the page to the reservation map. If the page allocation fails,
2146 * the reservation must be ended instead of committed. vma_end_reservation
2147 * is called in such cases.
2149 * In the normal case, vma_commit_reservation returns the same value
2150 * as the preceding vma_needs_reservation call. The only time this
2151 * is not the case is if a reserve map was changed between calls. It
2152 * is the responsibility of the caller to notice the difference and
2153 * take appropriate action.
2155 * vma_add_reservation is used in error paths where a reservation must
2156 * be restored when a newly allocated huge page must be freed. It is
2157 * to be called after calling vma_needs_reservation to determine if a
2158 * reservation exists.
2160 enum vma_resv_mode {
2166 static long __vma_reservation_common(struct hstate *h,
2167 struct vm_area_struct *vma, unsigned long addr,
2168 enum vma_resv_mode mode)
2170 struct resv_map *resv;
2173 long dummy_out_regions_needed;
2175 resv = vma_resv_map(vma);
2179 idx = vma_hugecache_offset(h, vma, addr);
2181 case VMA_NEEDS_RESV:
2182 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2183 /* We assume that vma_reservation_* routines always operate on
2184 * 1 page, and that adding to resv map a 1 page entry can only
2185 * ever require 1 region.
2187 VM_BUG_ON(dummy_out_regions_needed != 1);
2189 case VMA_COMMIT_RESV:
2190 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2191 /* region_add calls of range 1 should never fail. */
2195 region_abort(resv, idx, idx + 1, 1);
2199 if (vma->vm_flags & VM_MAYSHARE) {
2200 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2201 /* region_add calls of range 1 should never fail. */
2204 region_abort(resv, idx, idx + 1, 1);
2205 ret = region_del(resv, idx, idx + 1);
2212 if (vma->vm_flags & VM_MAYSHARE)
2214 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
2216 * In most cases, reserves always exist for private mappings.
2217 * However, a file associated with mapping could have been
2218 * hole punched or truncated after reserves were consumed.
2219 * As subsequent fault on such a range will not use reserves.
2220 * Subtle - The reserve map for private mappings has the
2221 * opposite meaning than that of shared mappings. If NO
2222 * entry is in the reserve map, it means a reservation exists.
2223 * If an entry exists in the reserve map, it means the
2224 * reservation has already been consumed. As a result, the
2225 * return value of this routine is the opposite of the
2226 * value returned from reserve map manipulation routines above.
2234 return ret < 0 ? ret : 0;
2237 static long vma_needs_reservation(struct hstate *h,
2238 struct vm_area_struct *vma, unsigned long addr)
2240 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2243 static long vma_commit_reservation(struct hstate *h,
2244 struct vm_area_struct *vma, unsigned long addr)
2246 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2249 static void vma_end_reservation(struct hstate *h,
2250 struct vm_area_struct *vma, unsigned long addr)
2252 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2255 static long vma_add_reservation(struct hstate *h,
2256 struct vm_area_struct *vma, unsigned long addr)
2258 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2262 * This routine is called to restore a reservation on error paths. In the
2263 * specific error paths, a huge page was allocated (via alloc_huge_page)
2264 * and is about to be freed. If a reservation for the page existed,
2265 * alloc_huge_page would have consumed the reservation and set
2266 * HPageRestoreReserve in the newly allocated page. When the page is freed
2267 * via free_huge_page, the global reservation count will be incremented if
2268 * HPageRestoreReserve is set. However, free_huge_page can not adjust the
2269 * reserve map. Adjust the reserve map here to be consistent with global
2270 * reserve count adjustments to be made by free_huge_page.
2272 static void restore_reserve_on_error(struct hstate *h,
2273 struct vm_area_struct *vma, unsigned long address,
2276 if (unlikely(HPageRestoreReserve(page))) {
2277 long rc = vma_needs_reservation(h, vma, address);
2279 if (unlikely(rc < 0)) {
2281 * Rare out of memory condition in reserve map
2282 * manipulation. Clear HPageRestoreReserve so that
2283 * global reserve count will not be incremented
2284 * by free_huge_page. This will make it appear
2285 * as though the reservation for this page was
2286 * consumed. This may prevent the task from
2287 * faulting in the page at a later time. This
2288 * is better than inconsistent global huge page
2289 * accounting of reserve counts.
2291 ClearHPageRestoreReserve(page);
2293 rc = vma_add_reservation(h, vma, address);
2294 if (unlikely(rc < 0))
2296 * See above comment about rare out of
2299 ClearHPageRestoreReserve(page);
2301 vma_end_reservation(h, vma, address);
2305 struct page *alloc_huge_page(struct vm_area_struct *vma,
2306 unsigned long addr, int avoid_reserve)
2308 struct hugepage_subpool *spool = subpool_vma(vma);
2309 struct hstate *h = hstate_vma(vma);
2311 long map_chg, map_commit;
2314 struct hugetlb_cgroup *h_cg;
2315 bool deferred_reserve;
2317 idx = hstate_index(h);
2319 * Examine the region/reserve map to determine if the process
2320 * has a reservation for the page to be allocated. A return
2321 * code of zero indicates a reservation exists (no change).
2323 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2325 return ERR_PTR(-ENOMEM);
2328 * Processes that did not create the mapping will have no
2329 * reserves as indicated by the region/reserve map. Check
2330 * that the allocation will not exceed the subpool limit.
2331 * Allocations for MAP_NORESERVE mappings also need to be
2332 * checked against any subpool limit.
2334 if (map_chg || avoid_reserve) {
2335 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2337 vma_end_reservation(h, vma, addr);
2338 return ERR_PTR(-ENOSPC);
2342 * Even though there was no reservation in the region/reserve
2343 * map, there could be reservations associated with the
2344 * subpool that can be used. This would be indicated if the
2345 * return value of hugepage_subpool_get_pages() is zero.
2346 * However, if avoid_reserve is specified we still avoid even
2347 * the subpool reservations.
2353 /* If this allocation is not consuming a reservation, charge it now.
2355 deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
2356 if (deferred_reserve) {
2357 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2358 idx, pages_per_huge_page(h), &h_cg);
2360 goto out_subpool_put;
2363 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2365 goto out_uncharge_cgroup_reservation;
2367 spin_lock(&hugetlb_lock);
2369 * glb_chg is passed to indicate whether or not a page must be taken
2370 * from the global free pool (global change). gbl_chg == 0 indicates
2371 * a reservation exists for the allocation.
2373 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2375 spin_unlock(&hugetlb_lock);
2376 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2378 goto out_uncharge_cgroup;
2379 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2380 SetHPageRestoreReserve(page);
2381 h->resv_huge_pages--;
2383 spin_lock(&hugetlb_lock);
2384 list_add(&page->lru, &h->hugepage_activelist);
2387 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2388 /* If allocation is not consuming a reservation, also store the
2389 * hugetlb_cgroup pointer on the page.
2391 if (deferred_reserve) {
2392 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2396 spin_unlock(&hugetlb_lock);
2398 hugetlb_set_page_subpool(page, spool);
2400 map_commit = vma_commit_reservation(h, vma, addr);
2401 if (unlikely(map_chg > map_commit)) {
2403 * The page was added to the reservation map between
2404 * vma_needs_reservation and vma_commit_reservation.
2405 * This indicates a race with hugetlb_reserve_pages.
2406 * Adjust for the subpool count incremented above AND
2407 * in hugetlb_reserve_pages for the same page. Also,
2408 * the reservation count added in hugetlb_reserve_pages
2409 * no longer applies.
2413 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2414 hugetlb_acct_memory(h, -rsv_adjust);
2415 if (deferred_reserve)
2416 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2417 pages_per_huge_page(h), page);
2421 out_uncharge_cgroup:
2422 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2423 out_uncharge_cgroup_reservation:
2424 if (deferred_reserve)
2425 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2428 if (map_chg || avoid_reserve)
2429 hugepage_subpool_put_pages(spool, 1);
2430 vma_end_reservation(h, vma, addr);
2431 return ERR_PTR(-ENOSPC);
2434 int alloc_bootmem_huge_page(struct hstate *h)
2435 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2436 int __alloc_bootmem_huge_page(struct hstate *h)
2438 struct huge_bootmem_page *m;
2441 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2444 addr = memblock_alloc_try_nid_raw(
2445 huge_page_size(h), huge_page_size(h),
2446 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2449 * Use the beginning of the huge page to store the
2450 * huge_bootmem_page struct (until gather_bootmem
2451 * puts them into the mem_map).
2460 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2461 /* Put them into a private list first because mem_map is not up yet */
2462 INIT_LIST_HEAD(&m->list);
2463 list_add(&m->list, &huge_boot_pages);
2468 static void __init prep_compound_huge_page(struct page *page,
2471 if (unlikely(order > (MAX_ORDER - 1)))
2472 prep_compound_gigantic_page(page, order);
2474 prep_compound_page(page, order);
2477 /* Put bootmem huge pages into the standard lists after mem_map is up */
2478 static void __init gather_bootmem_prealloc(void)
2480 struct huge_bootmem_page *m;
2482 list_for_each_entry(m, &huge_boot_pages, list) {
2483 struct page *page = virt_to_page(m);
2484 struct hstate *h = m->hstate;
2486 WARN_ON(page_count(page) != 1);
2487 prep_compound_huge_page(page, huge_page_order(h));
2488 WARN_ON(PageReserved(page));
2489 prep_new_huge_page(h, page, page_to_nid(page));
2490 put_page(page); /* free it into the hugepage allocator */
2493 * If we had gigantic hugepages allocated at boot time, we need
2494 * to restore the 'stolen' pages to totalram_pages in order to
2495 * fix confusing memory reports from free(1) and another
2496 * side-effects, like CommitLimit going negative.
2498 if (hstate_is_gigantic(h))
2499 adjust_managed_page_count(page, pages_per_huge_page(h));
2504 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2507 nodemask_t *node_alloc_noretry;
2509 if (!hstate_is_gigantic(h)) {
2511 * Bit mask controlling how hard we retry per-node allocations.
2512 * Ignore errors as lower level routines can deal with
2513 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2514 * time, we are likely in bigger trouble.
2516 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2519 /* allocations done at boot time */
2520 node_alloc_noretry = NULL;
2523 /* bit mask controlling how hard we retry per-node allocations */
2524 if (node_alloc_noretry)
2525 nodes_clear(*node_alloc_noretry);
2527 for (i = 0; i < h->max_huge_pages; ++i) {
2528 if (hstate_is_gigantic(h)) {
2529 if (hugetlb_cma_size) {
2530 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2533 if (!alloc_bootmem_huge_page(h))
2535 } else if (!alloc_pool_huge_page(h,
2536 &node_states[N_MEMORY],
2537 node_alloc_noretry))
2541 if (i < h->max_huge_pages) {
2544 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2545 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2546 h->max_huge_pages, buf, i);
2547 h->max_huge_pages = i;
2550 kfree(node_alloc_noretry);
2553 static void __init hugetlb_init_hstates(void)
2557 for_each_hstate(h) {
2558 if (minimum_order > huge_page_order(h))
2559 minimum_order = huge_page_order(h);
2561 /* oversize hugepages were init'ed in early boot */
2562 if (!hstate_is_gigantic(h))
2563 hugetlb_hstate_alloc_pages(h);
2565 VM_BUG_ON(minimum_order == UINT_MAX);
2568 static void __init report_hugepages(void)
2572 for_each_hstate(h) {
2575 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2576 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2577 buf, h->free_huge_pages);
2581 #ifdef CONFIG_HIGHMEM
2582 static void try_to_free_low(struct hstate *h, unsigned long count,
2583 nodemask_t *nodes_allowed)
2587 if (hstate_is_gigantic(h))
2590 for_each_node_mask(i, *nodes_allowed) {
2591 struct page *page, *next;
2592 struct list_head *freel = &h->hugepage_freelists[i];
2593 list_for_each_entry_safe(page, next, freel, lru) {
2594 if (count >= h->nr_huge_pages)
2596 if (PageHighMem(page))
2598 list_del(&page->lru);
2599 update_and_free_page(h, page);
2600 h->free_huge_pages--;
2601 h->free_huge_pages_node[page_to_nid(page)]--;
2606 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2607 nodemask_t *nodes_allowed)
2613 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2614 * balanced by operating on them in a round-robin fashion.
2615 * Returns 1 if an adjustment was made.
2617 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2622 VM_BUG_ON(delta != -1 && delta != 1);
2625 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2626 if (h->surplus_huge_pages_node[node])
2630 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2631 if (h->surplus_huge_pages_node[node] <
2632 h->nr_huge_pages_node[node])
2639 h->surplus_huge_pages += delta;
2640 h->surplus_huge_pages_node[node] += delta;
2644 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2645 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2646 nodemask_t *nodes_allowed)
2648 unsigned long min_count, ret;
2649 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2652 * Bit mask controlling how hard we retry per-node allocations.
2653 * If we can not allocate the bit mask, do not attempt to allocate
2654 * the requested huge pages.
2656 if (node_alloc_noretry)
2657 nodes_clear(*node_alloc_noretry);
2661 spin_lock(&hugetlb_lock);
2664 * Check for a node specific request.
2665 * Changing node specific huge page count may require a corresponding
2666 * change to the global count. In any case, the passed node mask
2667 * (nodes_allowed) will restrict alloc/free to the specified node.
2669 if (nid != NUMA_NO_NODE) {
2670 unsigned long old_count = count;
2672 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2674 * User may have specified a large count value which caused the
2675 * above calculation to overflow. In this case, they wanted
2676 * to allocate as many huge pages as possible. Set count to
2677 * largest possible value to align with their intention.
2679 if (count < old_count)
2684 * Gigantic pages runtime allocation depend on the capability for large
2685 * page range allocation.
2686 * If the system does not provide this feature, return an error when
2687 * the user tries to allocate gigantic pages but let the user free the
2688 * boottime allocated gigantic pages.
2690 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2691 if (count > persistent_huge_pages(h)) {
2692 spin_unlock(&hugetlb_lock);
2693 NODEMASK_FREE(node_alloc_noretry);
2696 /* Fall through to decrease pool */
2700 * Increase the pool size
2701 * First take pages out of surplus state. Then make up the
2702 * remaining difference by allocating fresh huge pages.
2704 * We might race with alloc_surplus_huge_page() here and be unable
2705 * to convert a surplus huge page to a normal huge page. That is
2706 * not critical, though, it just means the overall size of the
2707 * pool might be one hugepage larger than it needs to be, but
2708 * within all the constraints specified by the sysctls.
2710 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2711 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2715 while (count > persistent_huge_pages(h)) {
2717 * If this allocation races such that we no longer need the
2718 * page, free_huge_page will handle it by freeing the page
2719 * and reducing the surplus.
2721 spin_unlock(&hugetlb_lock);
2723 /* yield cpu to avoid soft lockup */
2726 ret = alloc_pool_huge_page(h, nodes_allowed,
2727 node_alloc_noretry);
2728 spin_lock(&hugetlb_lock);
2732 /* Bail for signals. Probably ctrl-c from user */
2733 if (signal_pending(current))
2738 * Decrease the pool size
2739 * First return free pages to the buddy allocator (being careful
2740 * to keep enough around to satisfy reservations). Then place
2741 * pages into surplus state as needed so the pool will shrink
2742 * to the desired size as pages become free.
2744 * By placing pages into the surplus state independent of the
2745 * overcommit value, we are allowing the surplus pool size to
2746 * exceed overcommit. There are few sane options here. Since
2747 * alloc_surplus_huge_page() is checking the global counter,
2748 * though, we'll note that we're not allowed to exceed surplus
2749 * and won't grow the pool anywhere else. Not until one of the
2750 * sysctls are changed, or the surplus pages go out of use.
2752 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2753 min_count = max(count, min_count);
2754 try_to_free_low(h, min_count, nodes_allowed);
2755 while (min_count < persistent_huge_pages(h)) {
2756 if (!free_pool_huge_page(h, nodes_allowed, 0))
2758 cond_resched_lock(&hugetlb_lock);
2760 while (count < persistent_huge_pages(h)) {
2761 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2765 h->max_huge_pages = persistent_huge_pages(h);
2766 spin_unlock(&hugetlb_lock);
2768 NODEMASK_FREE(node_alloc_noretry);
2773 #define HSTATE_ATTR_RO(_name) \
2774 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2776 #define HSTATE_ATTR(_name) \
2777 static struct kobj_attribute _name##_attr = \
2778 __ATTR(_name, 0644, _name##_show, _name##_store)
2780 static struct kobject *hugepages_kobj;
2781 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2783 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2785 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2789 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2790 if (hstate_kobjs[i] == kobj) {
2792 *nidp = NUMA_NO_NODE;
2796 return kobj_to_node_hstate(kobj, nidp);
2799 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2800 struct kobj_attribute *attr, char *buf)
2803 unsigned long nr_huge_pages;
2806 h = kobj_to_hstate(kobj, &nid);
2807 if (nid == NUMA_NO_NODE)
2808 nr_huge_pages = h->nr_huge_pages;
2810 nr_huge_pages = h->nr_huge_pages_node[nid];
2812 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
2815 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2816 struct hstate *h, int nid,
2817 unsigned long count, size_t len)
2820 nodemask_t nodes_allowed, *n_mask;
2822 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2825 if (nid == NUMA_NO_NODE) {
2827 * global hstate attribute
2829 if (!(obey_mempolicy &&
2830 init_nodemask_of_mempolicy(&nodes_allowed)))
2831 n_mask = &node_states[N_MEMORY];
2833 n_mask = &nodes_allowed;
2836 * Node specific request. count adjustment happens in
2837 * set_max_huge_pages() after acquiring hugetlb_lock.
2839 init_nodemask_of_node(&nodes_allowed, nid);
2840 n_mask = &nodes_allowed;
2843 err = set_max_huge_pages(h, count, nid, n_mask);
2845 return err ? err : len;
2848 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2849 struct kobject *kobj, const char *buf,
2853 unsigned long count;
2857 err = kstrtoul(buf, 10, &count);
2861 h = kobj_to_hstate(kobj, &nid);
2862 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2865 static ssize_t nr_hugepages_show(struct kobject *kobj,
2866 struct kobj_attribute *attr, char *buf)
2868 return nr_hugepages_show_common(kobj, attr, buf);
2871 static ssize_t nr_hugepages_store(struct kobject *kobj,
2872 struct kobj_attribute *attr, const char *buf, size_t len)
2874 return nr_hugepages_store_common(false, kobj, buf, len);
2876 HSTATE_ATTR(nr_hugepages);
2881 * hstate attribute for optionally mempolicy-based constraint on persistent
2882 * huge page alloc/free.
2884 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2885 struct kobj_attribute *attr,
2888 return nr_hugepages_show_common(kobj, attr, buf);
2891 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2892 struct kobj_attribute *attr, const char *buf, size_t len)
2894 return nr_hugepages_store_common(true, kobj, buf, len);
2896 HSTATE_ATTR(nr_hugepages_mempolicy);
2900 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2901 struct kobj_attribute *attr, char *buf)
2903 struct hstate *h = kobj_to_hstate(kobj, NULL);
2904 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
2907 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2908 struct kobj_attribute *attr, const char *buf, size_t count)
2911 unsigned long input;
2912 struct hstate *h = kobj_to_hstate(kobj, NULL);
2914 if (hstate_is_gigantic(h))
2917 err = kstrtoul(buf, 10, &input);
2921 spin_lock(&hugetlb_lock);
2922 h->nr_overcommit_huge_pages = input;
2923 spin_unlock(&hugetlb_lock);
2927 HSTATE_ATTR(nr_overcommit_hugepages);
2929 static ssize_t free_hugepages_show(struct kobject *kobj,
2930 struct kobj_attribute *attr, char *buf)
2933 unsigned long free_huge_pages;
2936 h = kobj_to_hstate(kobj, &nid);
2937 if (nid == NUMA_NO_NODE)
2938 free_huge_pages = h->free_huge_pages;
2940 free_huge_pages = h->free_huge_pages_node[nid];
2942 return sysfs_emit(buf, "%lu\n", free_huge_pages);
2944 HSTATE_ATTR_RO(free_hugepages);
2946 static ssize_t resv_hugepages_show(struct kobject *kobj,
2947 struct kobj_attribute *attr, char *buf)
2949 struct hstate *h = kobj_to_hstate(kobj, NULL);
2950 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
2952 HSTATE_ATTR_RO(resv_hugepages);
2954 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2955 struct kobj_attribute *attr, char *buf)
2958 unsigned long surplus_huge_pages;
2961 h = kobj_to_hstate(kobj, &nid);
2962 if (nid == NUMA_NO_NODE)
2963 surplus_huge_pages = h->surplus_huge_pages;
2965 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2967 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
2969 HSTATE_ATTR_RO(surplus_hugepages);
2971 static struct attribute *hstate_attrs[] = {
2972 &nr_hugepages_attr.attr,
2973 &nr_overcommit_hugepages_attr.attr,
2974 &free_hugepages_attr.attr,
2975 &resv_hugepages_attr.attr,
2976 &surplus_hugepages_attr.attr,
2978 &nr_hugepages_mempolicy_attr.attr,
2983 static const struct attribute_group hstate_attr_group = {
2984 .attrs = hstate_attrs,
2987 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2988 struct kobject **hstate_kobjs,
2989 const struct attribute_group *hstate_attr_group)
2992 int hi = hstate_index(h);
2994 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2995 if (!hstate_kobjs[hi])
2998 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3000 kobject_put(hstate_kobjs[hi]);
3001 hstate_kobjs[hi] = NULL;
3007 static void __init hugetlb_sysfs_init(void)
3012 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3013 if (!hugepages_kobj)
3016 for_each_hstate(h) {
3017 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3018 hstate_kobjs, &hstate_attr_group);
3020 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3027 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3028 * with node devices in node_devices[] using a parallel array. The array
3029 * index of a node device or _hstate == node id.
3030 * This is here to avoid any static dependency of the node device driver, in
3031 * the base kernel, on the hugetlb module.
3033 struct node_hstate {
3034 struct kobject *hugepages_kobj;
3035 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3037 static struct node_hstate node_hstates[MAX_NUMNODES];
3040 * A subset of global hstate attributes for node devices
3042 static struct attribute *per_node_hstate_attrs[] = {
3043 &nr_hugepages_attr.attr,
3044 &free_hugepages_attr.attr,
3045 &surplus_hugepages_attr.attr,
3049 static const struct attribute_group per_node_hstate_attr_group = {
3050 .attrs = per_node_hstate_attrs,
3054 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3055 * Returns node id via non-NULL nidp.
3057 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3061 for (nid = 0; nid < nr_node_ids; nid++) {
3062 struct node_hstate *nhs = &node_hstates[nid];
3064 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3065 if (nhs->hstate_kobjs[i] == kobj) {
3077 * Unregister hstate attributes from a single node device.
3078 * No-op if no hstate attributes attached.
3080 static void hugetlb_unregister_node(struct node *node)
3083 struct node_hstate *nhs = &node_hstates[node->dev.id];
3085 if (!nhs->hugepages_kobj)
3086 return; /* no hstate attributes */
3088 for_each_hstate(h) {
3089 int idx = hstate_index(h);
3090 if (nhs->hstate_kobjs[idx]) {
3091 kobject_put(nhs->hstate_kobjs[idx]);
3092 nhs->hstate_kobjs[idx] = NULL;
3096 kobject_put(nhs->hugepages_kobj);
3097 nhs->hugepages_kobj = NULL;
3102 * Register hstate attributes for a single node device.
3103 * No-op if attributes already registered.
3105 static void hugetlb_register_node(struct node *node)
3108 struct node_hstate *nhs = &node_hstates[node->dev.id];
3111 if (nhs->hugepages_kobj)
3112 return; /* already allocated */
3114 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3116 if (!nhs->hugepages_kobj)
3119 for_each_hstate(h) {
3120 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3122 &per_node_hstate_attr_group);
3124 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3125 h->name, node->dev.id);
3126 hugetlb_unregister_node(node);
3133 * hugetlb init time: register hstate attributes for all registered node
3134 * devices of nodes that have memory. All on-line nodes should have
3135 * registered their associated device by this time.
3137 static void __init hugetlb_register_all_nodes(void)
3141 for_each_node_state(nid, N_MEMORY) {
3142 struct node *node = node_devices[nid];
3143 if (node->dev.id == nid)
3144 hugetlb_register_node(node);
3148 * Let the node device driver know we're here so it can
3149 * [un]register hstate attributes on node hotplug.
3151 register_hugetlbfs_with_node(hugetlb_register_node,
3152 hugetlb_unregister_node);
3154 #else /* !CONFIG_NUMA */
3156 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3164 static void hugetlb_register_all_nodes(void) { }
3168 static int __init hugetlb_init(void)
3172 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3175 if (!hugepages_supported()) {
3176 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3177 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3182 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3183 * architectures depend on setup being done here.
3185 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3186 if (!parsed_default_hugepagesz) {
3188 * If we did not parse a default huge page size, set
3189 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3190 * number of huge pages for this default size was implicitly
3191 * specified, set that here as well.
3192 * Note that the implicit setting will overwrite an explicit
3193 * setting. A warning will be printed in this case.
3195 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3196 if (default_hstate_max_huge_pages) {
3197 if (default_hstate.max_huge_pages) {
3200 string_get_size(huge_page_size(&default_hstate),
3201 1, STRING_UNITS_2, buf, 32);
3202 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3203 default_hstate.max_huge_pages, buf);
3204 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3205 default_hstate_max_huge_pages);
3207 default_hstate.max_huge_pages =
3208 default_hstate_max_huge_pages;
3212 hugetlb_cma_check();
3213 hugetlb_init_hstates();
3214 gather_bootmem_prealloc();
3217 hugetlb_sysfs_init();
3218 hugetlb_register_all_nodes();
3219 hugetlb_cgroup_file_init();
3222 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3224 num_fault_mutexes = 1;
3226 hugetlb_fault_mutex_table =
3227 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3229 BUG_ON(!hugetlb_fault_mutex_table);
3231 for (i = 0; i < num_fault_mutexes; i++)
3232 mutex_init(&hugetlb_fault_mutex_table[i]);
3235 subsys_initcall(hugetlb_init);
3237 /* Overwritten by architectures with more huge page sizes */
3238 bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3240 return size == HPAGE_SIZE;
3243 void __init hugetlb_add_hstate(unsigned int order)
3248 if (size_to_hstate(PAGE_SIZE << order)) {
3251 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3253 h = &hstates[hugetlb_max_hstate++];
3255 h->mask = ~(huge_page_size(h) - 1);
3256 for (i = 0; i < MAX_NUMNODES; ++i)
3257 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3258 INIT_LIST_HEAD(&h->hugepage_activelist);
3259 h->next_nid_to_alloc = first_memory_node;
3260 h->next_nid_to_free = first_memory_node;
3261 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3262 huge_page_size(h)/1024);
3268 * hugepages command line processing
3269 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3270 * specification. If not, ignore the hugepages value. hugepages can also
3271 * be the first huge page command line option in which case it implicitly
3272 * specifies the number of huge pages for the default size.
3274 static int __init hugepages_setup(char *s)
3277 static unsigned long *last_mhp;
3279 if (!parsed_valid_hugepagesz) {
3280 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3281 parsed_valid_hugepagesz = true;
3286 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3287 * yet, so this hugepages= parameter goes to the "default hstate".
3288 * Otherwise, it goes with the previously parsed hugepagesz or
3289 * default_hugepagesz.
3291 else if (!hugetlb_max_hstate)
3292 mhp = &default_hstate_max_huge_pages;
3294 mhp = &parsed_hstate->max_huge_pages;
3296 if (mhp == last_mhp) {
3297 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3301 if (sscanf(s, "%lu", mhp) <= 0)
3305 * Global state is always initialized later in hugetlb_init.
3306 * But we need to allocate >= MAX_ORDER hstates here early to still
3307 * use the bootmem allocator.
3309 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3310 hugetlb_hstate_alloc_pages(parsed_hstate);
3316 __setup("hugepages=", hugepages_setup);
3319 * hugepagesz command line processing
3320 * A specific huge page size can only be specified once with hugepagesz.
3321 * hugepagesz is followed by hugepages on the command line. The global
3322 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3323 * hugepagesz argument was valid.
3325 static int __init hugepagesz_setup(char *s)
3330 parsed_valid_hugepagesz = false;
3331 size = (unsigned long)memparse(s, NULL);
3333 if (!arch_hugetlb_valid_size(size)) {
3334 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3338 h = size_to_hstate(size);
3341 * hstate for this size already exists. This is normally
3342 * an error, but is allowed if the existing hstate is the
3343 * default hstate. More specifically, it is only allowed if
3344 * the number of huge pages for the default hstate was not
3345 * previously specified.
3347 if (!parsed_default_hugepagesz || h != &default_hstate ||
3348 default_hstate.max_huge_pages) {
3349 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3354 * No need to call hugetlb_add_hstate() as hstate already
3355 * exists. But, do set parsed_hstate so that a following
3356 * hugepages= parameter will be applied to this hstate.
3359 parsed_valid_hugepagesz = true;
3363 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3364 parsed_valid_hugepagesz = true;
3367 __setup("hugepagesz=", hugepagesz_setup);
3370 * default_hugepagesz command line input
3371 * Only one instance of default_hugepagesz allowed on command line.
3373 static int __init default_hugepagesz_setup(char *s)
3377 parsed_valid_hugepagesz = false;
3378 if (parsed_default_hugepagesz) {
3379 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3383 size = (unsigned long)memparse(s, NULL);
3385 if (!arch_hugetlb_valid_size(size)) {
3386 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3390 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3391 parsed_valid_hugepagesz = true;
3392 parsed_default_hugepagesz = true;
3393 default_hstate_idx = hstate_index(size_to_hstate(size));
3396 * The number of default huge pages (for this size) could have been
3397 * specified as the first hugetlb parameter: hugepages=X. If so,
3398 * then default_hstate_max_huge_pages is set. If the default huge
3399 * page size is gigantic (>= MAX_ORDER), then the pages must be
3400 * allocated here from bootmem allocator.
3402 if (default_hstate_max_huge_pages) {
3403 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3404 if (hstate_is_gigantic(&default_hstate))
3405 hugetlb_hstate_alloc_pages(&default_hstate);
3406 default_hstate_max_huge_pages = 0;
3411 __setup("default_hugepagesz=", default_hugepagesz_setup);
3413 static unsigned int allowed_mems_nr(struct hstate *h)
3416 unsigned int nr = 0;
3417 nodemask_t *mpol_allowed;
3418 unsigned int *array = h->free_huge_pages_node;
3419 gfp_t gfp_mask = htlb_alloc_mask(h);
3421 mpol_allowed = policy_nodemask_current(gfp_mask);
3423 for_each_node_mask(node, cpuset_current_mems_allowed) {
3424 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3431 #ifdef CONFIG_SYSCTL
3432 static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3433 void *buffer, size_t *length,
3434 loff_t *ppos, unsigned long *out)
3436 struct ctl_table dup_table;
3439 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3440 * can duplicate the @table and alter the duplicate of it.
3443 dup_table.data = out;
3445 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3448 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3449 struct ctl_table *table, int write,
3450 void *buffer, size_t *length, loff_t *ppos)
3452 struct hstate *h = &default_hstate;
3453 unsigned long tmp = h->max_huge_pages;
3456 if (!hugepages_supported())
3459 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3465 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3466 NUMA_NO_NODE, tmp, *length);
3471 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3472 void *buffer, size_t *length, loff_t *ppos)
3475 return hugetlb_sysctl_handler_common(false, table, write,
3476 buffer, length, ppos);
3480 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3481 void *buffer, size_t *length, loff_t *ppos)
3483 return hugetlb_sysctl_handler_common(true, table, write,
3484 buffer, length, ppos);
3486 #endif /* CONFIG_NUMA */
3488 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3489 void *buffer, size_t *length, loff_t *ppos)
3491 struct hstate *h = &default_hstate;
3495 if (!hugepages_supported())
3498 tmp = h->nr_overcommit_huge_pages;
3500 if (write && hstate_is_gigantic(h))
3503 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3509 spin_lock(&hugetlb_lock);
3510 h->nr_overcommit_huge_pages = tmp;
3511 spin_unlock(&hugetlb_lock);
3517 #endif /* CONFIG_SYSCTL */
3519 void hugetlb_report_meminfo(struct seq_file *m)
3522 unsigned long total = 0;
3524 if (!hugepages_supported())
3527 for_each_hstate(h) {
3528 unsigned long count = h->nr_huge_pages;
3530 total += huge_page_size(h) * count;
3532 if (h == &default_hstate)
3534 "HugePages_Total: %5lu\n"
3535 "HugePages_Free: %5lu\n"
3536 "HugePages_Rsvd: %5lu\n"
3537 "HugePages_Surp: %5lu\n"
3538 "Hugepagesize: %8lu kB\n",
3542 h->surplus_huge_pages,
3543 huge_page_size(h) / SZ_1K);
3546 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3549 int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3551 struct hstate *h = &default_hstate;
3553 if (!hugepages_supported())
3556 return sysfs_emit_at(buf, len,
3557 "Node %d HugePages_Total: %5u\n"
3558 "Node %d HugePages_Free: %5u\n"
3559 "Node %d HugePages_Surp: %5u\n",
3560 nid, h->nr_huge_pages_node[nid],
3561 nid, h->free_huge_pages_node[nid],
3562 nid, h->surplus_huge_pages_node[nid]);
3565 void hugetlb_show_meminfo(void)
3570 if (!hugepages_supported())
3573 for_each_node_state(nid, N_MEMORY)
3575 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3577 h->nr_huge_pages_node[nid],
3578 h->free_huge_pages_node[nid],
3579 h->surplus_huge_pages_node[nid],
3580 huge_page_size(h) / SZ_1K);
3583 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3585 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3586 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3589 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3590 unsigned long hugetlb_total_pages(void)
3593 unsigned long nr_total_pages = 0;
3596 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3597 return nr_total_pages;
3600 static int hugetlb_acct_memory(struct hstate *h, long delta)
3607 spin_lock(&hugetlb_lock);
3609 * When cpuset is configured, it breaks the strict hugetlb page
3610 * reservation as the accounting is done on a global variable. Such
3611 * reservation is completely rubbish in the presence of cpuset because
3612 * the reservation is not checked against page availability for the
3613 * current cpuset. Application can still potentially OOM'ed by kernel
3614 * with lack of free htlb page in cpuset that the task is in.
3615 * Attempt to enforce strict accounting with cpuset is almost
3616 * impossible (or too ugly) because cpuset is too fluid that
3617 * task or memory node can be dynamically moved between cpusets.
3619 * The change of semantics for shared hugetlb mapping with cpuset is
3620 * undesirable. However, in order to preserve some of the semantics,
3621 * we fall back to check against current free page availability as
3622 * a best attempt and hopefully to minimize the impact of changing
3623 * semantics that cpuset has.
3625 * Apart from cpuset, we also have memory policy mechanism that
3626 * also determines from which node the kernel will allocate memory
3627 * in a NUMA system. So similar to cpuset, we also should consider
3628 * the memory policy of the current task. Similar to the description
3632 if (gather_surplus_pages(h, delta) < 0)
3635 if (delta > allowed_mems_nr(h)) {
3636 return_unused_surplus_pages(h, delta);
3643 return_unused_surplus_pages(h, (unsigned long) -delta);
3646 spin_unlock(&hugetlb_lock);
3650 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3652 struct resv_map *resv = vma_resv_map(vma);
3655 * This new VMA should share its siblings reservation map if present.
3656 * The VMA will only ever have a valid reservation map pointer where
3657 * it is being copied for another still existing VMA. As that VMA
3658 * has a reference to the reservation map it cannot disappear until
3659 * after this open call completes. It is therefore safe to take a
3660 * new reference here without additional locking.
3662 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3663 kref_get(&resv->refs);
3666 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3668 struct hstate *h = hstate_vma(vma);
3669 struct resv_map *resv = vma_resv_map(vma);
3670 struct hugepage_subpool *spool = subpool_vma(vma);
3671 unsigned long reserve, start, end;
3674 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3677 start = vma_hugecache_offset(h, vma, vma->vm_start);
3678 end = vma_hugecache_offset(h, vma, vma->vm_end);
3680 reserve = (end - start) - region_count(resv, start, end);
3681 hugetlb_cgroup_uncharge_counter(resv, start, end);
3684 * Decrement reserve counts. The global reserve count may be
3685 * adjusted if the subpool has a minimum size.
3687 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3688 hugetlb_acct_memory(h, -gbl_reserve);
3691 kref_put(&resv->refs, resv_map_release);
3694 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3696 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3701 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3703 return huge_page_size(hstate_vma(vma));
3707 * We cannot handle pagefaults against hugetlb pages at all. They cause
3708 * handle_mm_fault() to try to instantiate regular-sized pages in the
3709 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3712 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3719 * When a new function is introduced to vm_operations_struct and added
3720 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3721 * This is because under System V memory model, mappings created via
3722 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3723 * their original vm_ops are overwritten with shm_vm_ops.
3725 const struct vm_operations_struct hugetlb_vm_ops = {
3726 .fault = hugetlb_vm_op_fault,
3727 .open = hugetlb_vm_op_open,
3728 .close = hugetlb_vm_op_close,
3729 .may_split = hugetlb_vm_op_split,
3730 .pagesize = hugetlb_vm_op_pagesize,
3733 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3739 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3740 vma->vm_page_prot)));
3742 entry = huge_pte_wrprotect(mk_huge_pte(page,
3743 vma->vm_page_prot));
3745 entry = pte_mkyoung(entry);
3746 entry = pte_mkhuge(entry);
3747 entry = arch_make_huge_pte(entry, vma, page, writable);
3752 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3753 unsigned long address, pte_t *ptep)
3757 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3758 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3759 update_mmu_cache(vma, address, ptep);
3762 bool is_hugetlb_entry_migration(pte_t pte)
3766 if (huge_pte_none(pte) || pte_present(pte))
3768 swp = pte_to_swp_entry(pte);
3769 if (is_migration_entry(swp))
3775 static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3779 if (huge_pte_none(pte) || pte_present(pte))
3781 swp = pte_to_swp_entry(pte);
3782 if (is_hwpoison_entry(swp))
3788 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3789 struct vm_area_struct *vma)
3791 pte_t *src_pte, *dst_pte, entry, dst_entry;
3792 struct page *ptepage;
3795 struct hstate *h = hstate_vma(vma);
3796 unsigned long sz = huge_page_size(h);
3797 struct address_space *mapping = vma->vm_file->f_mapping;
3798 struct mmu_notifier_range range;
3801 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3804 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3807 mmu_notifier_invalidate_range_start(&range);
3810 * For shared mappings i_mmap_rwsem must be held to call
3811 * huge_pte_alloc, otherwise the returned ptep could go
3812 * away if part of a shared pmd and another thread calls
3815 i_mmap_lock_read(mapping);
3818 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3819 spinlock_t *src_ptl, *dst_ptl;
3820 src_pte = huge_pte_offset(src, addr, sz);
3823 dst_pte = huge_pte_alloc(dst, addr, sz);
3830 * If the pagetables are shared don't copy or take references.
3831 * dst_pte == src_pte is the common case of src/dest sharing.
3833 * However, src could have 'unshared' and dst shares with
3834 * another vma. If dst_pte !none, this implies sharing.
3835 * Check here before taking page table lock, and once again
3836 * after taking the lock below.
3838 dst_entry = huge_ptep_get(dst_pte);
3839 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3842 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3843 src_ptl = huge_pte_lockptr(h, src, src_pte);
3844 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3845 entry = huge_ptep_get(src_pte);
3846 dst_entry = huge_ptep_get(dst_pte);
3847 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3849 * Skip if src entry none. Also, skip in the
3850 * unlikely case dst entry !none as this implies
3851 * sharing with another vma.
3854 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3855 is_hugetlb_entry_hwpoisoned(entry))) {
3856 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3858 if (is_write_migration_entry(swp_entry) && cow) {
3860 * COW mappings require pages in both
3861 * parent and child to be set to read.
3863 make_migration_entry_read(&swp_entry);
3864 entry = swp_entry_to_pte(swp_entry);
3865 set_huge_swap_pte_at(src, addr, src_pte,
3868 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3872 * No need to notify as we are downgrading page
3873 * table protection not changing it to point
3876 * See Documentation/vm/mmu_notifier.rst
3878 huge_ptep_set_wrprotect(src, addr, src_pte);
3880 entry = huge_ptep_get(src_pte);
3881 ptepage = pte_page(entry);
3883 page_dup_rmap(ptepage, true);
3884 set_huge_pte_at(dst, addr, dst_pte, entry);
3885 hugetlb_count_add(pages_per_huge_page(h), dst);
3887 spin_unlock(src_ptl);
3888 spin_unlock(dst_ptl);
3892 mmu_notifier_invalidate_range_end(&range);
3894 i_mmap_unlock_read(mapping);
3899 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3900 unsigned long start, unsigned long end,
3901 struct page *ref_page)
3903 struct mm_struct *mm = vma->vm_mm;
3904 unsigned long address;
3909 struct hstate *h = hstate_vma(vma);
3910 unsigned long sz = huge_page_size(h);
3911 struct mmu_notifier_range range;
3913 WARN_ON(!is_vm_hugetlb_page(vma));
3914 BUG_ON(start & ~huge_page_mask(h));
3915 BUG_ON(end & ~huge_page_mask(h));
3918 * This is a hugetlb vma, all the pte entries should point
3921 tlb_change_page_size(tlb, sz);
3922 tlb_start_vma(tlb, vma);
3925 * If sharing possible, alert mmu notifiers of worst case.
3927 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
3929 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
3930 mmu_notifier_invalidate_range_start(&range);
3932 for (; address < end; address += sz) {
3933 ptep = huge_pte_offset(mm, address, sz);
3937 ptl = huge_pte_lock(h, mm, ptep);
3938 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3941 * We just unmapped a page of PMDs by clearing a PUD.
3942 * The caller's TLB flush range should cover this area.
3947 pte = huge_ptep_get(ptep);
3948 if (huge_pte_none(pte)) {
3954 * Migrating hugepage or HWPoisoned hugepage is already
3955 * unmapped and its refcount is dropped, so just clear pte here.
3957 if (unlikely(!pte_present(pte))) {
3958 huge_pte_clear(mm, address, ptep, sz);
3963 page = pte_page(pte);
3965 * If a reference page is supplied, it is because a specific
3966 * page is being unmapped, not a range. Ensure the page we
3967 * are about to unmap is the actual page of interest.
3970 if (page != ref_page) {
3975 * Mark the VMA as having unmapped its page so that
3976 * future faults in this VMA will fail rather than
3977 * looking like data was lost
3979 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3982 pte = huge_ptep_get_and_clear(mm, address, ptep);
3983 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3984 if (huge_pte_dirty(pte))
3985 set_page_dirty(page);
3987 hugetlb_count_sub(pages_per_huge_page(h), mm);
3988 page_remove_rmap(page, true);
3991 tlb_remove_page_size(tlb, page, huge_page_size(h));
3993 * Bail out after unmapping reference page if supplied
3998 mmu_notifier_invalidate_range_end(&range);
3999 tlb_end_vma(tlb, vma);
4002 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4003 struct vm_area_struct *vma, unsigned long start,
4004 unsigned long end, struct page *ref_page)
4006 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4009 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4010 * test will fail on a vma being torn down, and not grab a page table
4011 * on its way out. We're lucky that the flag has such an appropriate
4012 * name, and can in fact be safely cleared here. We could clear it
4013 * before the __unmap_hugepage_range above, but all that's necessary
4014 * is to clear it before releasing the i_mmap_rwsem. This works
4015 * because in the context this is called, the VMA is about to be
4016 * destroyed and the i_mmap_rwsem is held.
4018 vma->vm_flags &= ~VM_MAYSHARE;
4021 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4022 unsigned long end, struct page *ref_page)
4024 struct mmu_gather tlb;
4026 tlb_gather_mmu(&tlb, vma->vm_mm);
4027 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4028 tlb_finish_mmu(&tlb);
4032 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4033 * mapping it owns the reserve page for. The intention is to unmap the page
4034 * from other VMAs and let the children be SIGKILLed if they are faulting the
4037 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4038 struct page *page, unsigned long address)
4040 struct hstate *h = hstate_vma(vma);
4041 struct vm_area_struct *iter_vma;
4042 struct address_space *mapping;
4046 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4047 * from page cache lookup which is in HPAGE_SIZE units.
4049 address = address & huge_page_mask(h);
4050 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4052 mapping = vma->vm_file->f_mapping;
4055 * Take the mapping lock for the duration of the table walk. As
4056 * this mapping should be shared between all the VMAs,
4057 * __unmap_hugepage_range() is called as the lock is already held
4059 i_mmap_lock_write(mapping);
4060 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4061 /* Do not unmap the current VMA */
4062 if (iter_vma == vma)
4066 * Shared VMAs have their own reserves and do not affect
4067 * MAP_PRIVATE accounting but it is possible that a shared
4068 * VMA is using the same page so check and skip such VMAs.
4070 if (iter_vma->vm_flags & VM_MAYSHARE)
4074 * Unmap the page from other VMAs without their own reserves.
4075 * They get marked to be SIGKILLed if they fault in these
4076 * areas. This is because a future no-page fault on this VMA
4077 * could insert a zeroed page instead of the data existing
4078 * from the time of fork. This would look like data corruption
4080 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4081 unmap_hugepage_range(iter_vma, address,
4082 address + huge_page_size(h), page);
4084 i_mmap_unlock_write(mapping);
4088 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4089 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4090 * cannot race with other handlers or page migration.
4091 * Keep the pte_same checks anyway to make transition from the mutex easier.
4093 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4094 unsigned long address, pte_t *ptep,
4095 struct page *pagecache_page, spinlock_t *ptl)
4098 struct hstate *h = hstate_vma(vma);
4099 struct page *old_page, *new_page;
4100 int outside_reserve = 0;
4102 unsigned long haddr = address & huge_page_mask(h);
4103 struct mmu_notifier_range range;
4105 pte = huge_ptep_get(ptep);
4106 old_page = pte_page(pte);
4109 /* If no-one else is actually using this page, avoid the copy
4110 * and just make the page writable */
4111 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4112 page_move_anon_rmap(old_page, vma);
4113 set_huge_ptep_writable(vma, haddr, ptep);
4118 * If the process that created a MAP_PRIVATE mapping is about to
4119 * perform a COW due to a shared page count, attempt to satisfy
4120 * the allocation without using the existing reserves. The pagecache
4121 * page is used to determine if the reserve at this address was
4122 * consumed or not. If reserves were used, a partial faulted mapping
4123 * at the time of fork() could consume its reserves on COW instead
4124 * of the full address range.
4126 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4127 old_page != pagecache_page)
4128 outside_reserve = 1;
4133 * Drop page table lock as buddy allocator may be called. It will
4134 * be acquired again before returning to the caller, as expected.
4137 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4139 if (IS_ERR(new_page)) {
4141 * If a process owning a MAP_PRIVATE mapping fails to COW,
4142 * it is due to references held by a child and an insufficient
4143 * huge page pool. To guarantee the original mappers
4144 * reliability, unmap the page from child processes. The child
4145 * may get SIGKILLed if it later faults.
4147 if (outside_reserve) {
4148 struct address_space *mapping = vma->vm_file->f_mapping;
4153 BUG_ON(huge_pte_none(pte));
4155 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4156 * unmapping. unmapping needs to hold i_mmap_rwsem
4157 * in write mode. Dropping i_mmap_rwsem in read mode
4158 * here is OK as COW mappings do not interact with
4161 * Reacquire both after unmap operation.
4163 idx = vma_hugecache_offset(h, vma, haddr);
4164 hash = hugetlb_fault_mutex_hash(mapping, idx);
4165 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4166 i_mmap_unlock_read(mapping);
4168 unmap_ref_private(mm, vma, old_page, haddr);
4170 i_mmap_lock_read(mapping);
4171 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4173 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4175 pte_same(huge_ptep_get(ptep), pte)))
4176 goto retry_avoidcopy;
4178 * race occurs while re-acquiring page table
4179 * lock, and our job is done.
4184 ret = vmf_error(PTR_ERR(new_page));
4185 goto out_release_old;
4189 * When the original hugepage is shared one, it does not have
4190 * anon_vma prepared.
4192 if (unlikely(anon_vma_prepare(vma))) {
4194 goto out_release_all;
4197 copy_user_huge_page(new_page, old_page, address, vma,
4198 pages_per_huge_page(h));
4199 __SetPageUptodate(new_page);
4201 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4202 haddr + huge_page_size(h));
4203 mmu_notifier_invalidate_range_start(&range);
4206 * Retake the page table lock to check for racing updates
4207 * before the page tables are altered
4210 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4211 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4212 ClearHPageRestoreReserve(new_page);
4215 huge_ptep_clear_flush(vma, haddr, ptep);
4216 mmu_notifier_invalidate_range(mm, range.start, range.end);
4217 set_huge_pte_at(mm, haddr, ptep,
4218 make_huge_pte(vma, new_page, 1));
4219 page_remove_rmap(old_page, true);
4220 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4221 set_page_huge_active(new_page);
4222 /* Make the old page be freed below */
4223 new_page = old_page;
4226 mmu_notifier_invalidate_range_end(&range);
4228 restore_reserve_on_error(h, vma, haddr, new_page);
4233 spin_lock(ptl); /* Caller expects lock to be held */
4237 /* Return the pagecache page at a given address within a VMA */
4238 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4239 struct vm_area_struct *vma, unsigned long address)
4241 struct address_space *mapping;
4244 mapping = vma->vm_file->f_mapping;
4245 idx = vma_hugecache_offset(h, vma, address);
4247 return find_lock_page(mapping, idx);
4251 * Return whether there is a pagecache page to back given address within VMA.
4252 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4254 static bool hugetlbfs_pagecache_present(struct hstate *h,
4255 struct vm_area_struct *vma, unsigned long address)
4257 struct address_space *mapping;
4261 mapping = vma->vm_file->f_mapping;
4262 idx = vma_hugecache_offset(h, vma, address);
4264 page = find_get_page(mapping, idx);
4267 return page != NULL;
4270 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4273 struct inode *inode = mapping->host;
4274 struct hstate *h = hstate_inode(inode);
4275 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4279 ClearHPageRestoreReserve(page);
4282 * set page dirty so that it will not be removed from cache/file
4283 * by non-hugetlbfs specific code paths.
4285 set_page_dirty(page);
4287 spin_lock(&inode->i_lock);
4288 inode->i_blocks += blocks_per_huge_page(h);
4289 spin_unlock(&inode->i_lock);
4293 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4294 struct vm_area_struct *vma,
4295 struct address_space *mapping, pgoff_t idx,
4296 unsigned long address, pte_t *ptep, unsigned int flags)
4298 struct hstate *h = hstate_vma(vma);
4299 vm_fault_t ret = VM_FAULT_SIGBUS;
4305 unsigned long haddr = address & huge_page_mask(h);
4306 bool new_page = false;
4309 * Currently, we are forced to kill the process in the event the
4310 * original mapper has unmapped pages from the child due to a failed
4311 * COW. Warn that such a situation has occurred as it may not be obvious
4313 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4314 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4320 * We can not race with truncation due to holding i_mmap_rwsem.
4321 * i_size is modified when holding i_mmap_rwsem, so check here
4322 * once for faults beyond end of file.
4324 size = i_size_read(mapping->host) >> huge_page_shift(h);
4329 page = find_lock_page(mapping, idx);
4332 * Check for page in userfault range
4334 if (userfaultfd_missing(vma)) {
4336 struct vm_fault vmf = {
4341 * Hard to debug if it ends up being
4342 * used by a callee that assumes
4343 * something about the other
4344 * uninitialized fields... same as in
4350 * hugetlb_fault_mutex and i_mmap_rwsem must be
4351 * dropped before handling userfault. Reacquire
4352 * after handling fault to make calling code simpler.
4354 hash = hugetlb_fault_mutex_hash(mapping, idx);
4355 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4356 i_mmap_unlock_read(mapping);
4357 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4358 i_mmap_lock_read(mapping);
4359 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4363 page = alloc_huge_page(vma, haddr, 0);
4366 * Returning error will result in faulting task being
4367 * sent SIGBUS. The hugetlb fault mutex prevents two
4368 * tasks from racing to fault in the same page which
4369 * could result in false unable to allocate errors.
4370 * Page migration does not take the fault mutex, but
4371 * does a clear then write of pte's under page table
4372 * lock. Page fault code could race with migration,
4373 * notice the clear pte and try to allocate a page
4374 * here. Before returning error, get ptl and make
4375 * sure there really is no pte entry.
4377 ptl = huge_pte_lock(h, mm, ptep);
4378 if (!huge_pte_none(huge_ptep_get(ptep))) {
4384 ret = vmf_error(PTR_ERR(page));
4387 clear_huge_page(page, address, pages_per_huge_page(h));
4388 __SetPageUptodate(page);
4391 if (vma->vm_flags & VM_MAYSHARE) {
4392 int err = huge_add_to_page_cache(page, mapping, idx);
4401 if (unlikely(anon_vma_prepare(vma))) {
4403 goto backout_unlocked;
4409 * If memory error occurs between mmap() and fault, some process
4410 * don't have hwpoisoned swap entry for errored virtual address.
4411 * So we need to block hugepage fault by PG_hwpoison bit check.
4413 if (unlikely(PageHWPoison(page))) {
4414 ret = VM_FAULT_HWPOISON_LARGE |
4415 VM_FAULT_SET_HINDEX(hstate_index(h));
4416 goto backout_unlocked;
4421 * If we are going to COW a private mapping later, we examine the
4422 * pending reservations for this page now. This will ensure that
4423 * any allocations necessary to record that reservation occur outside
4426 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4427 if (vma_needs_reservation(h, vma, haddr) < 0) {
4429 goto backout_unlocked;
4431 /* Just decrements count, does not deallocate */
4432 vma_end_reservation(h, vma, haddr);
4435 ptl = huge_pte_lock(h, mm, ptep);
4437 if (!huge_pte_none(huge_ptep_get(ptep)))
4441 ClearHPageRestoreReserve(page);
4442 hugepage_add_new_anon_rmap(page, vma, haddr);
4444 page_dup_rmap(page, true);
4445 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4446 && (vma->vm_flags & VM_SHARED)));
4447 set_huge_pte_at(mm, haddr, ptep, new_pte);
4449 hugetlb_count_add(pages_per_huge_page(h), mm);
4450 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4451 /* Optimization, do the COW without a second fault */
4452 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4458 * Only make newly allocated pages active. Existing pages found
4459 * in the pagecache could be !page_huge_active() if they have been
4460 * isolated for migration.
4463 set_page_huge_active(page);
4473 restore_reserve_on_error(h, vma, haddr, page);
4479 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4481 unsigned long key[2];
4484 key[0] = (unsigned long) mapping;
4487 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4489 return hash & (num_fault_mutexes - 1);
4493 * For uniprocessor systems we always use a single mutex, so just
4494 * return 0 and avoid the hashing overhead.
4496 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4502 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4503 unsigned long address, unsigned int flags)
4510 struct page *page = NULL;
4511 struct page *pagecache_page = NULL;
4512 struct hstate *h = hstate_vma(vma);
4513 struct address_space *mapping;
4514 int need_wait_lock = 0;
4515 unsigned long haddr = address & huge_page_mask(h);
4517 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4520 * Since we hold no locks, ptep could be stale. That is
4521 * OK as we are only making decisions based on content and
4522 * not actually modifying content here.
4524 entry = huge_ptep_get(ptep);
4525 if (unlikely(is_hugetlb_entry_migration(entry))) {
4526 migration_entry_wait_huge(vma, mm, ptep);
4528 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4529 return VM_FAULT_HWPOISON_LARGE |
4530 VM_FAULT_SET_HINDEX(hstate_index(h));
4534 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4535 * until finished with ptep. This serves two purposes:
4536 * 1) It prevents huge_pmd_unshare from being called elsewhere
4537 * and making the ptep no longer valid.
4538 * 2) It synchronizes us with i_size modifications during truncation.
4540 * ptep could have already be assigned via huge_pte_offset. That
4541 * is OK, as huge_pte_alloc will return the same value unless
4542 * something has changed.
4544 mapping = vma->vm_file->f_mapping;
4545 i_mmap_lock_read(mapping);
4546 ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
4548 i_mmap_unlock_read(mapping);
4549 return VM_FAULT_OOM;
4553 * Serialize hugepage allocation and instantiation, so that we don't
4554 * get spurious allocation failures if two CPUs race to instantiate
4555 * the same page in the page cache.
4557 idx = vma_hugecache_offset(h, vma, haddr);
4558 hash = hugetlb_fault_mutex_hash(mapping, idx);
4559 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4561 entry = huge_ptep_get(ptep);
4562 if (huge_pte_none(entry)) {
4563 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4570 * entry could be a migration/hwpoison entry at this point, so this
4571 * check prevents the kernel from going below assuming that we have
4572 * an active hugepage in pagecache. This goto expects the 2nd page
4573 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4574 * properly handle it.
4576 if (!pte_present(entry))
4580 * If we are going to COW the mapping later, we examine the pending
4581 * reservations for this page now. This will ensure that any
4582 * allocations necessary to record that reservation occur outside the
4583 * spinlock. For private mappings, we also lookup the pagecache
4584 * page now as it is used to determine if a reservation has been
4587 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4588 if (vma_needs_reservation(h, vma, haddr) < 0) {
4592 /* Just decrements count, does not deallocate */
4593 vma_end_reservation(h, vma, haddr);
4595 if (!(vma->vm_flags & VM_MAYSHARE))
4596 pagecache_page = hugetlbfs_pagecache_page(h,
4600 ptl = huge_pte_lock(h, mm, ptep);
4602 /* Check for a racing update before calling hugetlb_cow */
4603 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4607 * hugetlb_cow() requires page locks of pte_page(entry) and
4608 * pagecache_page, so here we need take the former one
4609 * when page != pagecache_page or !pagecache_page.
4611 page = pte_page(entry);
4612 if (page != pagecache_page)
4613 if (!trylock_page(page)) {
4620 if (flags & FAULT_FLAG_WRITE) {
4621 if (!huge_pte_write(entry)) {
4622 ret = hugetlb_cow(mm, vma, address, ptep,
4623 pagecache_page, ptl);
4626 entry = huge_pte_mkdirty(entry);
4628 entry = pte_mkyoung(entry);
4629 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4630 flags & FAULT_FLAG_WRITE))
4631 update_mmu_cache(vma, haddr, ptep);
4633 if (page != pagecache_page)
4639 if (pagecache_page) {
4640 unlock_page(pagecache_page);
4641 put_page(pagecache_page);
4644 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4645 i_mmap_unlock_read(mapping);
4647 * Generally it's safe to hold refcount during waiting page lock. But
4648 * here we just wait to defer the next page fault to avoid busy loop and
4649 * the page is not used after unlocked before returning from the current
4650 * page fault. So we are safe from accessing freed page, even if we wait
4651 * here without taking refcount.
4654 wait_on_page_locked(page);
4659 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4660 * modifications for huge pages.
4662 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4664 struct vm_area_struct *dst_vma,
4665 unsigned long dst_addr,
4666 unsigned long src_addr,
4667 struct page **pagep)
4669 struct address_space *mapping;
4672 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4673 struct hstate *h = hstate_vma(dst_vma);
4681 page = alloc_huge_page(dst_vma, dst_addr, 0);
4685 ret = copy_huge_page_from_user(page,
4686 (const void __user *) src_addr,
4687 pages_per_huge_page(h), false);
4689 /* fallback to copy_from_user outside mmap_lock */
4690 if (unlikely(ret)) {
4693 /* don't free the page */
4702 * The memory barrier inside __SetPageUptodate makes sure that
4703 * preceding stores to the page contents become visible before
4704 * the set_pte_at() write.
4706 __SetPageUptodate(page);
4708 mapping = dst_vma->vm_file->f_mapping;
4709 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4712 * If shared, add to page cache
4715 size = i_size_read(mapping->host) >> huge_page_shift(h);
4718 goto out_release_nounlock;
4721 * Serialization between remove_inode_hugepages() and
4722 * huge_add_to_page_cache() below happens through the
4723 * hugetlb_fault_mutex_table that here must be hold by
4726 ret = huge_add_to_page_cache(page, mapping, idx);
4728 goto out_release_nounlock;
4731 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4735 * Recheck the i_size after holding PT lock to make sure not
4736 * to leave any page mapped (as page_mapped()) beyond the end
4737 * of the i_size (remove_inode_hugepages() is strict about
4738 * enforcing that). If we bail out here, we'll also leave a
4739 * page in the radix tree in the vm_shared case beyond the end
4740 * of the i_size, but remove_inode_hugepages() will take care
4741 * of it as soon as we drop the hugetlb_fault_mutex_table.
4743 size = i_size_read(mapping->host) >> huge_page_shift(h);
4746 goto out_release_unlock;
4749 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4750 goto out_release_unlock;
4753 page_dup_rmap(page, true);
4755 ClearHPageRestoreReserve(page);
4756 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4759 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4760 if (dst_vma->vm_flags & VM_WRITE)
4761 _dst_pte = huge_pte_mkdirty(_dst_pte);
4762 _dst_pte = pte_mkyoung(_dst_pte);
4764 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4766 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4767 dst_vma->vm_flags & VM_WRITE);
4768 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4770 /* No need to invalidate - it was non-present before */
4771 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4774 set_page_huge_active(page);
4784 out_release_nounlock:
4789 static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
4790 int refs, struct page **pages,
4791 struct vm_area_struct **vmas)
4795 for (nr = 0; nr < refs; nr++) {
4797 pages[nr] = mem_map_offset(page, nr);
4803 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4804 struct page **pages, struct vm_area_struct **vmas,
4805 unsigned long *position, unsigned long *nr_pages,
4806 long i, unsigned int flags, int *locked)
4808 unsigned long pfn_offset;
4809 unsigned long vaddr = *position;
4810 unsigned long remainder = *nr_pages;
4811 struct hstate *h = hstate_vma(vma);
4812 int err = -EFAULT, refs;
4814 while (vaddr < vma->vm_end && remainder) {
4816 spinlock_t *ptl = NULL;
4821 * If we have a pending SIGKILL, don't keep faulting pages and
4822 * potentially allocating memory.
4824 if (fatal_signal_pending(current)) {
4830 * Some archs (sparc64, sh*) have multiple pte_ts to
4831 * each hugepage. We have to make sure we get the
4832 * first, for the page indexing below to work.
4834 * Note that page table lock is not held when pte is null.
4836 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4839 ptl = huge_pte_lock(h, mm, pte);
4840 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4843 * When coredumping, it suits get_dump_page if we just return
4844 * an error where there's an empty slot with no huge pagecache
4845 * to back it. This way, we avoid allocating a hugepage, and
4846 * the sparse dumpfile avoids allocating disk blocks, but its
4847 * huge holes still show up with zeroes where they need to be.
4849 if (absent && (flags & FOLL_DUMP) &&
4850 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4858 * We need call hugetlb_fault for both hugepages under migration
4859 * (in which case hugetlb_fault waits for the migration,) and
4860 * hwpoisoned hugepages (in which case we need to prevent the
4861 * caller from accessing to them.) In order to do this, we use
4862 * here is_swap_pte instead of is_hugetlb_entry_migration and
4863 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4864 * both cases, and because we can't follow correct pages
4865 * directly from any kind of swap entries.
4867 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4868 ((flags & FOLL_WRITE) &&
4869 !huge_pte_write(huge_ptep_get(pte)))) {
4871 unsigned int fault_flags = 0;
4875 if (flags & FOLL_WRITE)
4876 fault_flags |= FAULT_FLAG_WRITE;
4878 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4879 FAULT_FLAG_KILLABLE;
4880 if (flags & FOLL_NOWAIT)
4881 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4882 FAULT_FLAG_RETRY_NOWAIT;
4883 if (flags & FOLL_TRIED) {
4885 * Note: FAULT_FLAG_ALLOW_RETRY and
4886 * FAULT_FLAG_TRIED can co-exist
4888 fault_flags |= FAULT_FLAG_TRIED;
4890 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4891 if (ret & VM_FAULT_ERROR) {
4892 err = vm_fault_to_errno(ret, flags);
4896 if (ret & VM_FAULT_RETRY) {
4898 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4902 * VM_FAULT_RETRY must not return an
4903 * error, it will return zero
4906 * No need to update "position" as the
4907 * caller will not check it after
4908 * *nr_pages is set to 0.
4915 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4916 page = pte_page(huge_ptep_get(pte));
4919 * If subpage information not requested, update counters
4920 * and skip the same_page loop below.
4922 if (!pages && !vmas && !pfn_offset &&
4923 (vaddr + huge_page_size(h) < vma->vm_end) &&
4924 (remainder >= pages_per_huge_page(h))) {
4925 vaddr += huge_page_size(h);
4926 remainder -= pages_per_huge_page(h);
4927 i += pages_per_huge_page(h);
4932 refs = min3(pages_per_huge_page(h) - pfn_offset,
4933 (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
4936 record_subpages_vmas(mem_map_offset(page, pfn_offset),
4938 likely(pages) ? pages + i : NULL,
4939 vmas ? vmas + i : NULL);
4943 * try_grab_compound_head() should always succeed here,
4944 * because: a) we hold the ptl lock, and b) we've just
4945 * checked that the huge page is present in the page
4946 * tables. If the huge page is present, then the tail
4947 * pages must also be present. The ptl prevents the
4948 * head page and tail pages from being rearranged in
4949 * any way. So this page must be available at this
4950 * point, unless the page refcount overflowed:
4952 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
4962 vaddr += (refs << PAGE_SHIFT);
4968 *nr_pages = remainder;
4970 * setting position is actually required only if remainder is
4971 * not zero but it's faster not to add a "if (remainder)"
4979 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4981 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4984 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4987 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4988 unsigned long address, unsigned long end, pgprot_t newprot)
4990 struct mm_struct *mm = vma->vm_mm;
4991 unsigned long start = address;
4994 struct hstate *h = hstate_vma(vma);
4995 unsigned long pages = 0;
4996 bool shared_pmd = false;
4997 struct mmu_notifier_range range;
5000 * In the case of shared PMDs, the area to flush could be beyond
5001 * start/end. Set range.start/range.end to cover the maximum possible
5002 * range if PMD sharing is possible.
5004 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5005 0, vma, mm, start, end);
5006 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5008 BUG_ON(address >= end);
5009 flush_cache_range(vma, range.start, range.end);
5011 mmu_notifier_invalidate_range_start(&range);
5012 i_mmap_lock_write(vma->vm_file->f_mapping);
5013 for (; address < end; address += huge_page_size(h)) {
5015 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5018 ptl = huge_pte_lock(h, mm, ptep);
5019 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5025 pte = huge_ptep_get(ptep);
5026 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5030 if (unlikely(is_hugetlb_entry_migration(pte))) {
5031 swp_entry_t entry = pte_to_swp_entry(pte);
5033 if (is_write_migration_entry(entry)) {
5036 make_migration_entry_read(&entry);
5037 newpte = swp_entry_to_pte(entry);
5038 set_huge_swap_pte_at(mm, address, ptep,
5039 newpte, huge_page_size(h));
5045 if (!huge_pte_none(pte)) {
5048 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5049 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5050 pte = arch_make_huge_pte(pte, vma, NULL, 0);
5051 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5057 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5058 * may have cleared our pud entry and done put_page on the page table:
5059 * once we release i_mmap_rwsem, another task can do the final put_page
5060 * and that page table be reused and filled with junk. If we actually
5061 * did unshare a page of pmds, flush the range corresponding to the pud.
5064 flush_hugetlb_tlb_range(vma, range.start, range.end);
5066 flush_hugetlb_tlb_range(vma, start, end);
5068 * No need to call mmu_notifier_invalidate_range() we are downgrading
5069 * page table protection not changing it to point to a new page.
5071 * See Documentation/vm/mmu_notifier.rst
5073 i_mmap_unlock_write(vma->vm_file->f_mapping);
5074 mmu_notifier_invalidate_range_end(&range);
5076 return pages << h->order;
5079 int hugetlb_reserve_pages(struct inode *inode,
5081 struct vm_area_struct *vma,
5082 vm_flags_t vm_flags)
5084 long ret, chg, add = -1;
5085 struct hstate *h = hstate_inode(inode);
5086 struct hugepage_subpool *spool = subpool_inode(inode);
5087 struct resv_map *resv_map;
5088 struct hugetlb_cgroup *h_cg = NULL;
5089 long gbl_reserve, regions_needed = 0;
5091 /* This should never happen */
5093 VM_WARN(1, "%s called with a negative range\n", __func__);
5098 * Only apply hugepage reservation if asked. At fault time, an
5099 * attempt will be made for VM_NORESERVE to allocate a page
5100 * without using reserves
5102 if (vm_flags & VM_NORESERVE)
5106 * Shared mappings base their reservation on the number of pages that
5107 * are already allocated on behalf of the file. Private mappings need
5108 * to reserve the full area even if read-only as mprotect() may be
5109 * called to make the mapping read-write. Assume !vma is a shm mapping
5111 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5113 * resv_map can not be NULL as hugetlb_reserve_pages is only
5114 * called for inodes for which resv_maps were created (see
5115 * hugetlbfs_get_inode).
5117 resv_map = inode_resv_map(inode);
5119 chg = region_chg(resv_map, from, to, ®ions_needed);
5122 /* Private mapping. */
5123 resv_map = resv_map_alloc();
5129 set_vma_resv_map(vma, resv_map);
5130 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5138 ret = hugetlb_cgroup_charge_cgroup_rsvd(
5139 hstate_index(h), chg * pages_per_huge_page(h), &h_cg);
5146 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5147 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5150 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5154 * There must be enough pages in the subpool for the mapping. If
5155 * the subpool has a minimum size, there may be some global
5156 * reservations already in place (gbl_reserve).
5158 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5159 if (gbl_reserve < 0) {
5161 goto out_uncharge_cgroup;
5165 * Check enough hugepages are available for the reservation.
5166 * Hand the pages back to the subpool if there are not
5168 ret = hugetlb_acct_memory(h, gbl_reserve);
5174 * Account for the reservations made. Shared mappings record regions
5175 * that have reservations as they are shared by multiple VMAs.
5176 * When the last VMA disappears, the region map says how much
5177 * the reservation was and the page cache tells how much of
5178 * the reservation was consumed. Private mappings are per-VMA and
5179 * only the consumed reservations are tracked. When the VMA
5180 * disappears, the original reservation is the VMA size and the
5181 * consumed reservations are stored in the map. Hence, nothing
5182 * else has to be done for private mappings here
5184 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5185 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5187 if (unlikely(add < 0)) {
5188 hugetlb_acct_memory(h, -gbl_reserve);
5191 } else if (unlikely(chg > add)) {
5193 * pages in this range were added to the reserve
5194 * map between region_chg and region_add. This
5195 * indicates a race with alloc_huge_page. Adjust
5196 * the subpool and reserve counts modified above
5197 * based on the difference.
5201 hugetlb_cgroup_uncharge_cgroup_rsvd(
5203 (chg - add) * pages_per_huge_page(h), h_cg);
5205 rsv_adjust = hugepage_subpool_put_pages(spool,
5207 hugetlb_acct_memory(h, -rsv_adjust);
5212 /* put back original number of pages, chg */
5213 (void)hugepage_subpool_put_pages(spool, chg);
5214 out_uncharge_cgroup:
5215 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5216 chg * pages_per_huge_page(h), h_cg);
5218 if (!vma || vma->vm_flags & VM_MAYSHARE)
5219 /* Only call region_abort if the region_chg succeeded but the
5220 * region_add failed or didn't run.
5222 if (chg >= 0 && add < 0)
5223 region_abort(resv_map, from, to, regions_needed);
5224 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5225 kref_put(&resv_map->refs, resv_map_release);
5229 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5232 struct hstate *h = hstate_inode(inode);
5233 struct resv_map *resv_map = inode_resv_map(inode);
5235 struct hugepage_subpool *spool = subpool_inode(inode);
5239 * Since this routine can be called in the evict inode path for all
5240 * hugetlbfs inodes, resv_map could be NULL.
5243 chg = region_del(resv_map, start, end);
5245 * region_del() can fail in the rare case where a region
5246 * must be split and another region descriptor can not be
5247 * allocated. If end == LONG_MAX, it will not fail.
5253 spin_lock(&inode->i_lock);
5254 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5255 spin_unlock(&inode->i_lock);
5258 * If the subpool has a minimum size, the number of global
5259 * reservations to be released may be adjusted.
5261 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5262 hugetlb_acct_memory(h, -gbl_reserve);
5267 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5268 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5269 struct vm_area_struct *vma,
5270 unsigned long addr, pgoff_t idx)
5272 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5274 unsigned long sbase = saddr & PUD_MASK;
5275 unsigned long s_end = sbase + PUD_SIZE;
5277 /* Allow segments to share if only one is marked locked */
5278 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5279 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5282 * match the virtual addresses, permission and the alignment of the
5285 if (pmd_index(addr) != pmd_index(saddr) ||
5286 vm_flags != svm_flags ||
5287 !range_in_vma(svma, sbase, s_end))
5293 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5295 unsigned long base = addr & PUD_MASK;
5296 unsigned long end = base + PUD_SIZE;
5299 * check on proper vm_flags and page table alignment
5301 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5307 * Determine if start,end range within vma could be mapped by shared pmd.
5308 * If yes, adjust start and end to cover range associated with possible
5309 * shared pmd mappings.
5311 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5312 unsigned long *start, unsigned long *end)
5314 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5315 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5318 * vma need span at least one aligned PUD size and the start,end range
5319 * must at least partialy within it.
5321 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5322 (*end <= v_start) || (*start >= v_end))
5325 /* Extend the range to be PUD aligned for a worst case scenario */
5326 if (*start > v_start)
5327 *start = ALIGN_DOWN(*start, PUD_SIZE);
5330 *end = ALIGN(*end, PUD_SIZE);
5334 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5335 * and returns the corresponding pte. While this is not necessary for the
5336 * !shared pmd case because we can allocate the pmd later as well, it makes the
5337 * code much cleaner.
5339 * This routine must be called with i_mmap_rwsem held in at least read mode if
5340 * sharing is possible. For hugetlbfs, this prevents removal of any page
5341 * table entries associated with the address space. This is important as we
5342 * are setting up sharing based on existing page table entries (mappings).
5344 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5345 * huge_pte_alloc know that sharing is not possible and do not take
5346 * i_mmap_rwsem as a performance optimization. This is handled by the
5347 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5348 * only required for subsequent processing.
5350 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5352 struct vm_area_struct *vma = find_vma(mm, addr);
5353 struct address_space *mapping = vma->vm_file->f_mapping;
5354 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5356 struct vm_area_struct *svma;
5357 unsigned long saddr;
5362 if (!vma_shareable(vma, addr))
5363 return (pte_t *)pmd_alloc(mm, pud, addr);
5365 i_mmap_assert_locked(mapping);
5366 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5370 saddr = page_table_shareable(svma, vma, addr, idx);
5372 spte = huge_pte_offset(svma->vm_mm, saddr,
5373 vma_mmu_pagesize(svma));
5375 get_page(virt_to_page(spte));
5384 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5385 if (pud_none(*pud)) {
5386 pud_populate(mm, pud,
5387 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5390 put_page(virt_to_page(spte));
5394 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5399 * unmap huge page backed by shared pte.
5401 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5402 * indicated by page_count > 1, unmap is achieved by clearing pud and
5403 * decrementing the ref count. If count == 1, the pte page is not shared.
5405 * Called with page table lock held and i_mmap_rwsem held in write mode.
5407 * returns: 1 successfully unmapped a shared pte page
5408 * 0 the underlying pte page is not shared, or it is the last user
5410 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5411 unsigned long *addr, pte_t *ptep)
5413 pgd_t *pgd = pgd_offset(mm, *addr);
5414 p4d_t *p4d = p4d_offset(pgd, *addr);
5415 pud_t *pud = pud_offset(p4d, *addr);
5417 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5418 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5419 if (page_count(virt_to_page(ptep)) == 1)
5423 put_page(virt_to_page(ptep));
5425 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5428 #define want_pmd_share() (1)
5429 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5430 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5435 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5436 unsigned long *addr, pte_t *ptep)
5441 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5442 unsigned long *start, unsigned long *end)
5445 #define want_pmd_share() (0)
5446 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5448 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5449 pte_t *huge_pte_alloc(struct mm_struct *mm,
5450 unsigned long addr, unsigned long sz)
5457 pgd = pgd_offset(mm, addr);
5458 p4d = p4d_alloc(mm, pgd, addr);
5461 pud = pud_alloc(mm, p4d, addr);
5463 if (sz == PUD_SIZE) {
5466 BUG_ON(sz != PMD_SIZE);
5467 if (want_pmd_share() && pud_none(*pud))
5468 pte = huge_pmd_share(mm, addr, pud);
5470 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5473 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5479 * huge_pte_offset() - Walk the page table to resolve the hugepage
5480 * entry at address @addr
5482 * Return: Pointer to page table entry (PUD or PMD) for
5483 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5484 * size @sz doesn't match the hugepage size at this level of the page
5487 pte_t *huge_pte_offset(struct mm_struct *mm,
5488 unsigned long addr, unsigned long sz)
5495 pgd = pgd_offset(mm, addr);
5496 if (!pgd_present(*pgd))
5498 p4d = p4d_offset(pgd, addr);
5499 if (!p4d_present(*p4d))
5502 pud = pud_offset(p4d, addr);
5504 /* must be pud huge, non-present or none */
5505 return (pte_t *)pud;
5506 if (!pud_present(*pud))
5508 /* must have a valid entry and size to go further */
5510 pmd = pmd_offset(pud, addr);
5511 /* must be pmd huge, non-present or none */
5512 return (pte_t *)pmd;
5515 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5518 * These functions are overwritable if your architecture needs its own
5521 struct page * __weak
5522 follow_huge_addr(struct mm_struct *mm, unsigned long address,
5525 return ERR_PTR(-EINVAL);
5528 struct page * __weak
5529 follow_huge_pd(struct vm_area_struct *vma,
5530 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5532 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5536 struct page * __weak
5537 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5538 pmd_t *pmd, int flags)
5540 struct page *page = NULL;
5544 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5545 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5546 (FOLL_PIN | FOLL_GET)))
5550 ptl = pmd_lockptr(mm, pmd);
5553 * make sure that the address range covered by this pmd is not
5554 * unmapped from other threads.
5556 if (!pmd_huge(*pmd))
5558 pte = huge_ptep_get((pte_t *)pmd);
5559 if (pte_present(pte)) {
5560 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5562 * try_grab_page() should always succeed here, because: a) we
5563 * hold the pmd (ptl) lock, and b) we've just checked that the
5564 * huge pmd (head) page is present in the page tables. The ptl
5565 * prevents the head page and tail pages from being rearranged
5566 * in any way. So this page must be available at this point,
5567 * unless the page refcount overflowed:
5569 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5574 if (is_hugetlb_entry_migration(pte)) {
5576 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5580 * hwpoisoned entry is treated as no_page_table in
5581 * follow_page_mask().
5589 struct page * __weak
5590 follow_huge_pud(struct mm_struct *mm, unsigned long address,
5591 pud_t *pud, int flags)
5593 if (flags & (FOLL_GET | FOLL_PIN))
5596 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5599 struct page * __weak
5600 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5602 if (flags & (FOLL_GET | FOLL_PIN))
5605 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5608 bool isolate_huge_page(struct page *page, struct list_head *list)
5612 spin_lock(&hugetlb_lock);
5613 if (!PageHeadHuge(page) || !page_huge_active(page) ||
5614 !get_page_unless_zero(page)) {
5618 clear_page_huge_active(page);
5619 list_move_tail(&page->lru, list);
5621 spin_unlock(&hugetlb_lock);
5625 void putback_active_hugepage(struct page *page)
5627 spin_lock(&hugetlb_lock);
5628 set_page_huge_active(page);
5629 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5630 spin_unlock(&hugetlb_lock);
5634 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5636 struct hstate *h = page_hstate(oldpage);
5638 hugetlb_cgroup_migrate(oldpage, newpage);
5639 set_page_owner_migrate_reason(newpage, reason);
5642 * transfer temporary state of the new huge page. This is
5643 * reverse to other transitions because the newpage is going to
5644 * be final while the old one will be freed so it takes over
5645 * the temporary status.
5647 * Also note that we have to transfer the per-node surplus state
5648 * here as well otherwise the global surplus count will not match
5651 if (PageHugeTemporary(newpage)) {
5652 int old_nid = page_to_nid(oldpage);
5653 int new_nid = page_to_nid(newpage);
5655 SetPageHugeTemporary(oldpage);
5656 ClearPageHugeTemporary(newpage);
5658 spin_lock(&hugetlb_lock);
5659 if (h->surplus_huge_pages_node[old_nid]) {
5660 h->surplus_huge_pages_node[old_nid]--;
5661 h->surplus_huge_pages_node[new_nid]++;
5663 spin_unlock(&hugetlb_lock);
5668 static bool cma_reserve_called __initdata;
5670 static int __init cmdline_parse_hugetlb_cma(char *p)
5672 hugetlb_cma_size = memparse(p, &p);
5676 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
5678 void __init hugetlb_cma_reserve(int order)
5680 unsigned long size, reserved, per_node;
5683 cma_reserve_called = true;
5685 if (!hugetlb_cma_size)
5688 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
5689 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5690 (PAGE_SIZE << order) / SZ_1M);
5695 * If 3 GB area is requested on a machine with 4 numa nodes,
5696 * let's allocate 1 GB on first three nodes and ignore the last one.
5698 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
5699 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5700 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
5703 for_each_node_state(nid, N_ONLINE) {
5705 char name[CMA_MAX_NAME];
5707 size = min(per_node, hugetlb_cma_size - reserved);
5708 size = round_up(size, PAGE_SIZE << order);
5710 snprintf(name, sizeof(name), "hugetlb%d", nid);
5711 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5713 &hugetlb_cma[nid], nid);
5715 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
5721 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
5724 if (reserved >= hugetlb_cma_size)
5729 void __init hugetlb_cma_check(void)
5731 if (!hugetlb_cma_size || cma_reserve_called)
5734 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
5737 #endif /* CONFIG_CMA */