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>
33 #include <linux/migrate.h>
36 #include <asm/pgalloc.h>
40 #include <linux/hugetlb.h>
41 #include <linux/hugetlb_cgroup.h>
42 #include <linux/node.h>
43 #include <linux/page_owner.h>
45 #include "hugetlb_vmemmap.h"
47 int hugetlb_max_hstate __read_mostly;
48 unsigned int default_hstate_idx;
49 struct hstate hstates[HUGE_MAX_HSTATE];
52 static struct cma *hugetlb_cma[MAX_NUMNODES];
54 static unsigned long hugetlb_cma_size __initdata;
57 * Minimum page order among possible hugepage sizes, set to a proper value
60 static unsigned int minimum_order __read_mostly = UINT_MAX;
62 __initdata LIST_HEAD(huge_boot_pages);
64 /* for command line parsing */
65 static struct hstate * __initdata parsed_hstate;
66 static unsigned long __initdata default_hstate_max_huge_pages;
67 static bool __initdata parsed_valid_hugepagesz = true;
68 static bool __initdata parsed_default_hugepagesz;
71 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
72 * free_huge_pages, and surplus_huge_pages.
74 DEFINE_SPINLOCK(hugetlb_lock);
77 * Serializes faults on the same logical page. This is used to
78 * prevent spurious OOMs when the hugepage pool is fully utilized.
80 static int num_fault_mutexes;
81 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
83 /* Forward declaration */
84 static int hugetlb_acct_memory(struct hstate *h, long delta);
86 static inline bool subpool_is_free(struct hugepage_subpool *spool)
90 if (spool->max_hpages != -1)
91 return spool->used_hpages == 0;
92 if (spool->min_hpages != -1)
93 return spool->rsv_hpages == spool->min_hpages;
98 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
99 unsigned long irq_flags)
101 spin_unlock_irqrestore(&spool->lock, irq_flags);
103 /* If no pages are used, and no other handles to the subpool
104 * remain, give up any reservations based on minimum size and
105 * free the subpool */
106 if (subpool_is_free(spool)) {
107 if (spool->min_hpages != -1)
108 hugetlb_acct_memory(spool->hstate,
114 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
117 struct hugepage_subpool *spool;
119 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
123 spin_lock_init(&spool->lock);
125 spool->max_hpages = max_hpages;
127 spool->min_hpages = min_hpages;
129 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
133 spool->rsv_hpages = min_hpages;
138 void hugepage_put_subpool(struct hugepage_subpool *spool)
142 spin_lock_irqsave(&spool->lock, flags);
143 BUG_ON(!spool->count);
145 unlock_or_release_subpool(spool, flags);
149 * Subpool accounting for allocating and reserving pages.
150 * Return -ENOMEM if there are not enough resources to satisfy the
151 * request. Otherwise, return the number of pages by which the
152 * global pools must be adjusted (upward). The returned value may
153 * only be different than the passed value (delta) in the case where
154 * a subpool minimum size must be maintained.
156 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
164 spin_lock_irq(&spool->lock);
166 if (spool->max_hpages != -1) { /* maximum size accounting */
167 if ((spool->used_hpages + delta) <= spool->max_hpages)
168 spool->used_hpages += delta;
175 /* minimum size accounting */
176 if (spool->min_hpages != -1 && spool->rsv_hpages) {
177 if (delta > spool->rsv_hpages) {
179 * Asking for more reserves than those already taken on
180 * behalf of subpool. Return difference.
182 ret = delta - spool->rsv_hpages;
183 spool->rsv_hpages = 0;
185 ret = 0; /* reserves already accounted for */
186 spool->rsv_hpages -= delta;
191 spin_unlock_irq(&spool->lock);
196 * Subpool accounting for freeing and unreserving pages.
197 * Return the number of global page reservations that must be dropped.
198 * The return value may only be different than the passed value (delta)
199 * in the case where a subpool minimum size must be maintained.
201 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
210 spin_lock_irqsave(&spool->lock, flags);
212 if (spool->max_hpages != -1) /* maximum size accounting */
213 spool->used_hpages -= delta;
215 /* minimum size accounting */
216 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
217 if (spool->rsv_hpages + delta <= spool->min_hpages)
220 ret = spool->rsv_hpages + delta - spool->min_hpages;
222 spool->rsv_hpages += delta;
223 if (spool->rsv_hpages > spool->min_hpages)
224 spool->rsv_hpages = spool->min_hpages;
228 * If hugetlbfs_put_super couldn't free spool due to an outstanding
229 * quota reference, free it now.
231 unlock_or_release_subpool(spool, flags);
236 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
238 return HUGETLBFS_SB(inode->i_sb)->spool;
241 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
243 return subpool_inode(file_inode(vma->vm_file));
246 /* Helper that removes a struct file_region from the resv_map cache and returns
249 static struct file_region *
250 get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
252 struct file_region *nrg = NULL;
254 VM_BUG_ON(resv->region_cache_count <= 0);
256 resv->region_cache_count--;
257 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
258 list_del(&nrg->link);
266 static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
267 struct file_region *rg)
269 #ifdef CONFIG_CGROUP_HUGETLB
270 nrg->reservation_counter = rg->reservation_counter;
277 /* Helper that records hugetlb_cgroup uncharge info. */
278 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
280 struct resv_map *resv,
281 struct file_region *nrg)
283 #ifdef CONFIG_CGROUP_HUGETLB
285 nrg->reservation_counter =
286 &h_cg->rsvd_hugepage[hstate_index(h)];
287 nrg->css = &h_cg->css;
289 * The caller will hold exactly one h_cg->css reference for the
290 * whole contiguous reservation region. But this area might be
291 * scattered when there are already some file_regions reside in
292 * it. As a result, many file_regions may share only one css
293 * reference. In order to ensure that one file_region must hold
294 * exactly one h_cg->css reference, we should do css_get for
295 * each file_region and leave the reference held by caller
299 if (!resv->pages_per_hpage)
300 resv->pages_per_hpage = pages_per_huge_page(h);
301 /* pages_per_hpage should be the same for all entries in
304 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
306 nrg->reservation_counter = NULL;
312 static void put_uncharge_info(struct file_region *rg)
314 #ifdef CONFIG_CGROUP_HUGETLB
320 static bool has_same_uncharge_info(struct file_region *rg,
321 struct file_region *org)
323 #ifdef CONFIG_CGROUP_HUGETLB
325 rg->reservation_counter == org->reservation_counter &&
333 static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
335 struct file_region *nrg = NULL, *prg = NULL;
337 prg = list_prev_entry(rg, link);
338 if (&prg->link != &resv->regions && prg->to == rg->from &&
339 has_same_uncharge_info(prg, rg)) {
343 put_uncharge_info(rg);
349 nrg = list_next_entry(rg, link);
350 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
351 has_same_uncharge_info(nrg, rg)) {
352 nrg->from = rg->from;
355 put_uncharge_info(rg);
361 hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
362 long to, struct hstate *h, struct hugetlb_cgroup *cg,
363 long *regions_needed)
365 struct file_region *nrg;
367 if (!regions_needed) {
368 nrg = get_file_region_entry_from_cache(map, from, to);
369 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
370 list_add(&nrg->link, rg->link.prev);
371 coalesce_file_region(map, nrg);
373 *regions_needed += 1;
379 * Must be called with resv->lock held.
381 * Calling this with regions_needed != NULL will count the number of pages
382 * to be added but will not modify the linked list. And regions_needed will
383 * indicate the number of file_regions needed in the cache to carry out to add
384 * the regions for this range.
386 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
387 struct hugetlb_cgroup *h_cg,
388 struct hstate *h, long *regions_needed)
391 struct list_head *head = &resv->regions;
392 long last_accounted_offset = f;
393 struct file_region *rg = NULL, *trg = NULL;
398 /* In this loop, we essentially handle an entry for the range
399 * [last_accounted_offset, rg->from), at every iteration, with some
402 list_for_each_entry_safe(rg, trg, head, link) {
403 /* Skip irrelevant regions that start before our range. */
405 /* If this region ends after the last accounted offset,
406 * then we need to update last_accounted_offset.
408 if (rg->to > last_accounted_offset)
409 last_accounted_offset = rg->to;
413 /* When we find a region that starts beyond our range, we've
419 /* Add an entry for last_accounted_offset -> rg->from, and
420 * update last_accounted_offset.
422 if (rg->from > last_accounted_offset)
423 add += hugetlb_resv_map_add(resv, rg,
424 last_accounted_offset,
428 last_accounted_offset = rg->to;
431 /* Handle the case where our range extends beyond
432 * last_accounted_offset.
434 if (last_accounted_offset < t)
435 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
436 t, h, h_cg, regions_needed);
442 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
444 static int allocate_file_region_entries(struct resv_map *resv,
446 __must_hold(&resv->lock)
448 struct list_head allocated_regions;
449 int to_allocate = 0, i = 0;
450 struct file_region *trg = NULL, *rg = NULL;
452 VM_BUG_ON(regions_needed < 0);
454 INIT_LIST_HEAD(&allocated_regions);
457 * Check for sufficient descriptors in the cache to accommodate
458 * the number of in progress add operations plus regions_needed.
460 * This is a while loop because when we drop the lock, some other call
461 * to region_add or region_del may have consumed some region_entries,
462 * so we keep looping here until we finally have enough entries for
463 * (adds_in_progress + regions_needed).
465 while (resv->region_cache_count <
466 (resv->adds_in_progress + regions_needed)) {
467 to_allocate = resv->adds_in_progress + regions_needed -
468 resv->region_cache_count;
470 /* At this point, we should have enough entries in the cache
471 * for all the existing adds_in_progress. We should only be
472 * needing to allocate for regions_needed.
474 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
476 spin_unlock(&resv->lock);
477 for (i = 0; i < to_allocate; i++) {
478 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
481 list_add(&trg->link, &allocated_regions);
484 spin_lock(&resv->lock);
486 list_splice(&allocated_regions, &resv->region_cache);
487 resv->region_cache_count += to_allocate;
493 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
501 * Add the huge page range represented by [f, t) to the reserve
502 * map. Regions will be taken from the cache to fill in this range.
503 * Sufficient regions should exist in the cache due to the previous
504 * call to region_chg with the same range, but in some cases the cache will not
505 * have sufficient entries due to races with other code doing region_add or
506 * region_del. The extra needed entries will be allocated.
508 * regions_needed is the out value provided by a previous call to region_chg.
510 * Return the number of new huge pages added to the map. This number is greater
511 * than or equal to zero. If file_region entries needed to be allocated for
512 * this operation and we were not able to allocate, it returns -ENOMEM.
513 * region_add of regions of length 1 never allocate file_regions and cannot
514 * fail; region_chg will always allocate at least 1 entry and a region_add for
515 * 1 page will only require at most 1 entry.
517 static long region_add(struct resv_map *resv, long f, long t,
518 long in_regions_needed, struct hstate *h,
519 struct hugetlb_cgroup *h_cg)
521 long add = 0, actual_regions_needed = 0;
523 spin_lock(&resv->lock);
526 /* Count how many regions are actually needed to execute this add. */
527 add_reservation_in_range(resv, f, t, NULL, NULL,
528 &actual_regions_needed);
531 * Check for sufficient descriptors in the cache to accommodate
532 * this add operation. Note that actual_regions_needed may be greater
533 * than in_regions_needed, as the resv_map may have been modified since
534 * the region_chg call. In this case, we need to make sure that we
535 * allocate extra entries, such that we have enough for all the
536 * existing adds_in_progress, plus the excess needed for this
539 if (actual_regions_needed > in_regions_needed &&
540 resv->region_cache_count <
541 resv->adds_in_progress +
542 (actual_regions_needed - in_regions_needed)) {
543 /* region_add operation of range 1 should never need to
544 * allocate file_region entries.
546 VM_BUG_ON(t - f <= 1);
548 if (allocate_file_region_entries(
549 resv, actual_regions_needed - in_regions_needed)) {
556 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
558 resv->adds_in_progress -= in_regions_needed;
560 spin_unlock(&resv->lock);
565 * Examine the existing reserve map and determine how many
566 * huge pages in the specified range [f, t) are NOT currently
567 * represented. This routine is called before a subsequent
568 * call to region_add that will actually modify the reserve
569 * map to add the specified range [f, t). region_chg does
570 * not change the number of huge pages represented by the
571 * map. A number of new file_region structures is added to the cache as a
572 * placeholder, for the subsequent region_add call to use. At least 1
573 * file_region structure is added.
575 * out_regions_needed is the number of regions added to the
576 * resv->adds_in_progress. This value needs to be provided to a follow up call
577 * to region_add or region_abort for proper accounting.
579 * Returns the number of huge pages that need to be added to the existing
580 * reservation map for the range [f, t). This number is greater or equal to
581 * zero. -ENOMEM is returned if a new file_region structure or cache entry
582 * is needed and can not be allocated.
584 static long region_chg(struct resv_map *resv, long f, long t,
585 long *out_regions_needed)
589 spin_lock(&resv->lock);
591 /* Count how many hugepages in this range are NOT represented. */
592 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
595 if (*out_regions_needed == 0)
596 *out_regions_needed = 1;
598 if (allocate_file_region_entries(resv, *out_regions_needed))
601 resv->adds_in_progress += *out_regions_needed;
603 spin_unlock(&resv->lock);
608 * Abort the in progress add operation. The adds_in_progress field
609 * of the resv_map keeps track of the operations in progress between
610 * calls to region_chg and region_add. Operations are sometimes
611 * aborted after the call to region_chg. In such cases, region_abort
612 * is called to decrement the adds_in_progress counter. regions_needed
613 * is the value returned by the region_chg call, it is used to decrement
614 * the adds_in_progress counter.
616 * NOTE: The range arguments [f, t) are not needed or used in this
617 * routine. They are kept to make reading the calling code easier as
618 * arguments will match the associated region_chg call.
620 static void region_abort(struct resv_map *resv, long f, long t,
623 spin_lock(&resv->lock);
624 VM_BUG_ON(!resv->region_cache_count);
625 resv->adds_in_progress -= regions_needed;
626 spin_unlock(&resv->lock);
630 * Delete the specified range [f, t) from the reserve map. If the
631 * t parameter is LONG_MAX, this indicates that ALL regions after f
632 * should be deleted. Locate the regions which intersect [f, t)
633 * and either trim, delete or split the existing regions.
635 * Returns the number of huge pages deleted from the reserve map.
636 * In the normal case, the return value is zero or more. In the
637 * case where a region must be split, a new region descriptor must
638 * be allocated. If the allocation fails, -ENOMEM will be returned.
639 * NOTE: If the parameter t == LONG_MAX, then we will never split
640 * a region and possibly return -ENOMEM. Callers specifying
641 * t == LONG_MAX do not need to check for -ENOMEM error.
643 static long region_del(struct resv_map *resv, long f, long t)
645 struct list_head *head = &resv->regions;
646 struct file_region *rg, *trg;
647 struct file_region *nrg = NULL;
651 spin_lock(&resv->lock);
652 list_for_each_entry_safe(rg, trg, head, link) {
654 * Skip regions before the range to be deleted. file_region
655 * ranges are normally of the form [from, to). However, there
656 * may be a "placeholder" entry in the map which is of the form
657 * (from, to) with from == to. Check for placeholder entries
658 * at the beginning of the range to be deleted.
660 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
666 if (f > rg->from && t < rg->to) { /* Must split region */
668 * Check for an entry in the cache before dropping
669 * lock and attempting allocation.
672 resv->region_cache_count > resv->adds_in_progress) {
673 nrg = list_first_entry(&resv->region_cache,
676 list_del(&nrg->link);
677 resv->region_cache_count--;
681 spin_unlock(&resv->lock);
682 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
689 hugetlb_cgroup_uncharge_file_region(
690 resv, rg, t - f, false);
692 /* New entry for end of split region */
696 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
698 INIT_LIST_HEAD(&nrg->link);
700 /* Original entry is trimmed */
703 list_add(&nrg->link, &rg->link);
708 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
709 del += rg->to - rg->from;
710 hugetlb_cgroup_uncharge_file_region(resv, rg,
711 rg->to - rg->from, true);
717 if (f <= rg->from) { /* Trim beginning of region */
718 hugetlb_cgroup_uncharge_file_region(resv, rg,
719 t - rg->from, false);
723 } else { /* Trim end of region */
724 hugetlb_cgroup_uncharge_file_region(resv, rg,
732 spin_unlock(&resv->lock);
738 * A rare out of memory error was encountered which prevented removal of
739 * the reserve map region for a page. The huge page itself was free'ed
740 * and removed from the page cache. This routine will adjust the subpool
741 * usage count, and the global reserve count if needed. By incrementing
742 * these counts, the reserve map entry which could not be deleted will
743 * appear as a "reserved" entry instead of simply dangling with incorrect
746 void hugetlb_fix_reserve_counts(struct inode *inode)
748 struct hugepage_subpool *spool = subpool_inode(inode);
750 bool reserved = false;
752 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
753 if (rsv_adjust > 0) {
754 struct hstate *h = hstate_inode(inode);
756 if (!hugetlb_acct_memory(h, 1))
758 } else if (!rsv_adjust) {
763 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
767 * Count and return the number of huge pages in the reserve map
768 * that intersect with the range [f, t).
770 static long region_count(struct resv_map *resv, long f, long t)
772 struct list_head *head = &resv->regions;
773 struct file_region *rg;
776 spin_lock(&resv->lock);
777 /* Locate each segment we overlap with, and count that overlap. */
778 list_for_each_entry(rg, head, link) {
787 seg_from = max(rg->from, f);
788 seg_to = min(rg->to, t);
790 chg += seg_to - seg_from;
792 spin_unlock(&resv->lock);
798 * Convert the address within this vma to the page offset within
799 * the mapping, in pagecache page units; huge pages here.
801 static pgoff_t vma_hugecache_offset(struct hstate *h,
802 struct vm_area_struct *vma, unsigned long address)
804 return ((address - vma->vm_start) >> huge_page_shift(h)) +
805 (vma->vm_pgoff >> huge_page_order(h));
808 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
809 unsigned long address)
811 return vma_hugecache_offset(hstate_vma(vma), vma, address);
813 EXPORT_SYMBOL_GPL(linear_hugepage_index);
816 * Return the size of the pages allocated when backing a VMA. In the majority
817 * cases this will be same size as used by the page table entries.
819 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
821 if (vma->vm_ops && vma->vm_ops->pagesize)
822 return vma->vm_ops->pagesize(vma);
825 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
828 * Return the page size being used by the MMU to back a VMA. In the majority
829 * of cases, the page size used by the kernel matches the MMU size. On
830 * architectures where it differs, an architecture-specific 'strong'
831 * version of this symbol is required.
833 __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
835 return vma_kernel_pagesize(vma);
839 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
840 * bits of the reservation map pointer, which are always clear due to
843 #define HPAGE_RESV_OWNER (1UL << 0)
844 #define HPAGE_RESV_UNMAPPED (1UL << 1)
845 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
848 * These helpers are used to track how many pages are reserved for
849 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
850 * is guaranteed to have their future faults succeed.
852 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
853 * the reserve counters are updated with the hugetlb_lock held. It is safe
854 * to reset the VMA at fork() time as it is not in use yet and there is no
855 * chance of the global counters getting corrupted as a result of the values.
857 * The private mapping reservation is represented in a subtly different
858 * manner to a shared mapping. A shared mapping has a region map associated
859 * with the underlying file, this region map represents the backing file
860 * pages which have ever had a reservation assigned which this persists even
861 * after the page is instantiated. A private mapping has a region map
862 * associated with the original mmap which is attached to all VMAs which
863 * reference it, this region map represents those offsets which have consumed
864 * reservation ie. where pages have been instantiated.
866 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
868 return (unsigned long)vma->vm_private_data;
871 static void set_vma_private_data(struct vm_area_struct *vma,
874 vma->vm_private_data = (void *)value;
878 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
879 struct hugetlb_cgroup *h_cg,
882 #ifdef CONFIG_CGROUP_HUGETLB
884 resv_map->reservation_counter = NULL;
885 resv_map->pages_per_hpage = 0;
886 resv_map->css = NULL;
888 resv_map->reservation_counter =
889 &h_cg->rsvd_hugepage[hstate_index(h)];
890 resv_map->pages_per_hpage = pages_per_huge_page(h);
891 resv_map->css = &h_cg->css;
896 struct resv_map *resv_map_alloc(void)
898 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
899 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
901 if (!resv_map || !rg) {
907 kref_init(&resv_map->refs);
908 spin_lock_init(&resv_map->lock);
909 INIT_LIST_HEAD(&resv_map->regions);
911 resv_map->adds_in_progress = 0;
913 * Initialize these to 0. On shared mappings, 0's here indicate these
914 * fields don't do cgroup accounting. On private mappings, these will be
915 * re-initialized to the proper values, to indicate that hugetlb cgroup
916 * reservations are to be un-charged from here.
918 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
920 INIT_LIST_HEAD(&resv_map->region_cache);
921 list_add(&rg->link, &resv_map->region_cache);
922 resv_map->region_cache_count = 1;
927 void resv_map_release(struct kref *ref)
929 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
930 struct list_head *head = &resv_map->region_cache;
931 struct file_region *rg, *trg;
933 /* Clear out any active regions before we release the map. */
934 region_del(resv_map, 0, LONG_MAX);
936 /* ... and any entries left in the cache */
937 list_for_each_entry_safe(rg, trg, head, link) {
942 VM_BUG_ON(resv_map->adds_in_progress);
947 static inline struct resv_map *inode_resv_map(struct inode *inode)
950 * At inode evict time, i_mapping may not point to the original
951 * address space within the inode. This original address space
952 * contains the pointer to the resv_map. So, always use the
953 * address space embedded within the inode.
954 * The VERY common case is inode->mapping == &inode->i_data but,
955 * this may not be true for device special inodes.
957 return (struct resv_map *)(&inode->i_data)->private_data;
960 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
962 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
963 if (vma->vm_flags & VM_MAYSHARE) {
964 struct address_space *mapping = vma->vm_file->f_mapping;
965 struct inode *inode = mapping->host;
967 return inode_resv_map(inode);
970 return (struct resv_map *)(get_vma_private_data(vma) &
975 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
977 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
978 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
980 set_vma_private_data(vma, (get_vma_private_data(vma) &
981 HPAGE_RESV_MASK) | (unsigned long)map);
984 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
986 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
987 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
989 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
992 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
994 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
996 return (get_vma_private_data(vma) & flag) != 0;
999 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
1000 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
1002 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1003 if (!(vma->vm_flags & VM_MAYSHARE))
1004 vma->vm_private_data = (void *)0;
1007 /* Returns true if the VMA has associated reserve pages */
1008 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1010 if (vma->vm_flags & VM_NORESERVE) {
1012 * This address is already reserved by other process(chg == 0),
1013 * so, we should decrement reserved count. Without decrementing,
1014 * reserve count remains after releasing inode, because this
1015 * allocated page will go into page cache and is regarded as
1016 * coming from reserved pool in releasing step. Currently, we
1017 * don't have any other solution to deal with this situation
1018 * properly, so add work-around here.
1020 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1026 /* Shared mappings always use reserves */
1027 if (vma->vm_flags & VM_MAYSHARE) {
1029 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1030 * be a region map for all pages. The only situation where
1031 * there is no region map is if a hole was punched via
1032 * fallocate. In this case, there really are no reserves to
1033 * use. This situation is indicated if chg != 0.
1042 * Only the process that called mmap() has reserves for
1045 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1047 * Like the shared case above, a hole punch or truncate
1048 * could have been performed on the private mapping.
1049 * Examine the value of chg to determine if reserves
1050 * actually exist or were previously consumed.
1051 * Very Subtle - The value of chg comes from a previous
1052 * call to vma_needs_reserves(). The reserve map for
1053 * private mappings has different (opposite) semantics
1054 * than that of shared mappings. vma_needs_reserves()
1055 * has already taken this difference in semantics into
1056 * account. Therefore, the meaning of chg is the same
1057 * as in the shared case above. Code could easily be
1058 * combined, but keeping it separate draws attention to
1059 * subtle differences.
1070 static void enqueue_huge_page(struct hstate *h, struct page *page)
1072 int nid = page_to_nid(page);
1074 lockdep_assert_held(&hugetlb_lock);
1075 list_move(&page->lru, &h->hugepage_freelists[nid]);
1076 h->free_huge_pages++;
1077 h->free_huge_pages_node[nid]++;
1078 SetHPageFreed(page);
1081 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1084 bool pin = !!(current->flags & PF_MEMALLOC_PIN);
1086 lockdep_assert_held(&hugetlb_lock);
1087 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1088 if (pin && !is_pinnable_page(page))
1091 if (PageHWPoison(page))
1094 list_move(&page->lru, &h->hugepage_activelist);
1095 set_page_refcounted(page);
1096 ClearHPageFreed(page);
1097 h->free_huge_pages--;
1098 h->free_huge_pages_node[nid]--;
1105 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1108 unsigned int cpuset_mems_cookie;
1109 struct zonelist *zonelist;
1112 int node = NUMA_NO_NODE;
1114 zonelist = node_zonelist(nid, gfp_mask);
1117 cpuset_mems_cookie = read_mems_allowed_begin();
1118 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1121 if (!cpuset_zone_allowed(zone, gfp_mask))
1124 * no need to ask again on the same node. Pool is node rather than
1127 if (zone_to_nid(zone) == node)
1129 node = zone_to_nid(zone);
1131 page = dequeue_huge_page_node_exact(h, node);
1135 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1141 static struct page *dequeue_huge_page_vma(struct hstate *h,
1142 struct vm_area_struct *vma,
1143 unsigned long address, int avoid_reserve,
1147 struct mempolicy *mpol;
1149 nodemask_t *nodemask;
1153 * A child process with MAP_PRIVATE mappings created by their parent
1154 * have no page reserves. This check ensures that reservations are
1155 * not "stolen". The child may still get SIGKILLed
1157 if (!vma_has_reserves(vma, chg) &&
1158 h->free_huge_pages - h->resv_huge_pages == 0)
1161 /* If reserves cannot be used, ensure enough pages are in the pool */
1162 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1165 gfp_mask = htlb_alloc_mask(h);
1166 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1167 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1168 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1169 SetHPageRestoreReserve(page);
1170 h->resv_huge_pages--;
1173 mpol_cond_put(mpol);
1181 * common helper functions for hstate_next_node_to_{alloc|free}.
1182 * We may have allocated or freed a huge page based on a different
1183 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1184 * be outside of *nodes_allowed. Ensure that we use an allowed
1185 * node for alloc or free.
1187 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1189 nid = next_node_in(nid, *nodes_allowed);
1190 VM_BUG_ON(nid >= MAX_NUMNODES);
1195 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1197 if (!node_isset(nid, *nodes_allowed))
1198 nid = next_node_allowed(nid, nodes_allowed);
1203 * returns the previously saved node ["this node"] from which to
1204 * allocate a persistent huge page for the pool and advance the
1205 * next node from which to allocate, handling wrap at end of node
1208 static int hstate_next_node_to_alloc(struct hstate *h,
1209 nodemask_t *nodes_allowed)
1213 VM_BUG_ON(!nodes_allowed);
1215 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1216 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1222 * helper for remove_pool_huge_page() - return the previously saved
1223 * node ["this node"] from which to free a huge page. Advance the
1224 * next node id whether or not we find a free huge page to free so
1225 * that the next attempt to free addresses the next node.
1227 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1231 VM_BUG_ON(!nodes_allowed);
1233 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1234 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1239 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1240 for (nr_nodes = nodes_weight(*mask); \
1242 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1245 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1246 for (nr_nodes = nodes_weight(*mask); \
1248 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1251 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1252 static void destroy_compound_gigantic_page(struct page *page,
1256 int nr_pages = 1 << order;
1257 struct page *p = page + 1;
1259 atomic_set(compound_mapcount_ptr(page), 0);
1260 atomic_set(compound_pincount_ptr(page), 0);
1262 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1263 clear_compound_head(p);
1264 set_page_refcounted(p);
1267 set_compound_order(page, 0);
1268 page[1].compound_nr = 0;
1269 __ClearPageHead(page);
1272 static void free_gigantic_page(struct page *page, unsigned int order)
1275 * If the page isn't allocated using the cma allocator,
1276 * cma_release() returns false.
1279 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1283 free_contig_range(page_to_pfn(page), 1 << order);
1286 #ifdef CONFIG_CONTIG_ALLOC
1287 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1288 int nid, nodemask_t *nodemask)
1290 unsigned long nr_pages = pages_per_huge_page(h);
1291 if (nid == NUMA_NO_NODE)
1292 nid = numa_mem_id();
1299 if (hugetlb_cma[nid]) {
1300 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1301 huge_page_order(h), true);
1306 if (!(gfp_mask & __GFP_THISNODE)) {
1307 for_each_node_mask(node, *nodemask) {
1308 if (node == nid || !hugetlb_cma[node])
1311 page = cma_alloc(hugetlb_cma[node], nr_pages,
1312 huge_page_order(h), true);
1320 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1323 #else /* !CONFIG_CONTIG_ALLOC */
1324 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1325 int nid, nodemask_t *nodemask)
1329 #endif /* CONFIG_CONTIG_ALLOC */
1331 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1332 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1333 int nid, nodemask_t *nodemask)
1337 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1338 static inline void destroy_compound_gigantic_page(struct page *page,
1339 unsigned int order) { }
1343 * Remove hugetlb page from lists, and update dtor so that page appears
1344 * as just a compound page. A reference is held on the page.
1346 * Must be called with hugetlb lock held.
1348 static void remove_hugetlb_page(struct hstate *h, struct page *page,
1349 bool adjust_surplus)
1351 int nid = page_to_nid(page);
1353 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1354 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1356 lockdep_assert_held(&hugetlb_lock);
1357 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1360 list_del(&page->lru);
1362 if (HPageFreed(page)) {
1363 h->free_huge_pages--;
1364 h->free_huge_pages_node[nid]--;
1366 if (adjust_surplus) {
1367 h->surplus_huge_pages--;
1368 h->surplus_huge_pages_node[nid]--;
1371 set_page_refcounted(page);
1372 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1375 h->nr_huge_pages_node[nid]--;
1378 static void add_hugetlb_page(struct hstate *h, struct page *page,
1379 bool adjust_surplus)
1382 int nid = page_to_nid(page);
1384 VM_BUG_ON_PAGE(!HPageVmemmapOptimized(page), page);
1386 lockdep_assert_held(&hugetlb_lock);
1388 INIT_LIST_HEAD(&page->lru);
1390 h->nr_huge_pages_node[nid]++;
1392 if (adjust_surplus) {
1393 h->surplus_huge_pages++;
1394 h->surplus_huge_pages_node[nid]++;
1397 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1398 set_page_private(page, 0);
1399 SetHPageVmemmapOptimized(page);
1402 * This page is now managed by the hugetlb allocator and has
1403 * no users -- drop the last reference.
1405 zeroed = put_page_testzero(page);
1406 VM_BUG_ON_PAGE(!zeroed, page);
1407 arch_clear_hugepage_flags(page);
1408 enqueue_huge_page(h, page);
1411 static void __update_and_free_page(struct hstate *h, struct page *page)
1414 struct page *subpage = page;
1416 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1419 if (alloc_huge_page_vmemmap(h, page)) {
1420 spin_lock_irq(&hugetlb_lock);
1422 * If we cannot allocate vmemmap pages, just refuse to free the
1423 * page and put the page back on the hugetlb free list and treat
1424 * as a surplus page.
1426 add_hugetlb_page(h, page, true);
1427 spin_unlock_irq(&hugetlb_lock);
1431 for (i = 0; i < pages_per_huge_page(h);
1432 i++, subpage = mem_map_next(subpage, page, i)) {
1433 subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1434 1 << PG_referenced | 1 << PG_dirty |
1435 1 << PG_active | 1 << PG_private |
1438 if (hstate_is_gigantic(h)) {
1439 destroy_compound_gigantic_page(page, huge_page_order(h));
1440 free_gigantic_page(page, huge_page_order(h));
1442 __free_pages(page, huge_page_order(h));
1447 * As update_and_free_page() can be called under any context, so we cannot
1448 * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the
1449 * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate
1450 * the vmemmap pages.
1452 * free_hpage_workfn() locklessly retrieves the linked list of pages to be
1453 * freed and frees them one-by-one. As the page->mapping pointer is going
1454 * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node
1455 * structure of a lockless linked list of huge pages to be freed.
1457 static LLIST_HEAD(hpage_freelist);
1459 static void free_hpage_workfn(struct work_struct *work)
1461 struct llist_node *node;
1463 node = llist_del_all(&hpage_freelist);
1469 page = container_of((struct address_space **)node,
1470 struct page, mapping);
1472 page->mapping = NULL;
1474 * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate()
1475 * is going to trigger because a previous call to
1476 * remove_hugetlb_page() will set_compound_page_dtor(page,
1477 * NULL_COMPOUND_DTOR), so do not use page_hstate() directly.
1479 h = size_to_hstate(page_size(page));
1481 __update_and_free_page(h, page);
1486 static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1488 static inline void flush_free_hpage_work(struct hstate *h)
1490 if (free_vmemmap_pages_per_hpage(h))
1491 flush_work(&free_hpage_work);
1494 static void update_and_free_page(struct hstate *h, struct page *page,
1497 if (!HPageVmemmapOptimized(page) || !atomic) {
1498 __update_and_free_page(h, page);
1503 * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages.
1505 * Only call schedule_work() if hpage_freelist is previously
1506 * empty. Otherwise, schedule_work() had been called but the workfn
1507 * hasn't retrieved the list yet.
1509 if (llist_add((struct llist_node *)&page->mapping, &hpage_freelist))
1510 schedule_work(&free_hpage_work);
1513 static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
1515 struct page *page, *t_page;
1517 list_for_each_entry_safe(page, t_page, list, lru) {
1518 update_and_free_page(h, page, false);
1523 struct hstate *size_to_hstate(unsigned long size)
1527 for_each_hstate(h) {
1528 if (huge_page_size(h) == size)
1534 void free_huge_page(struct page *page)
1537 * Can't pass hstate in here because it is called from the
1538 * compound page destructor.
1540 struct hstate *h = page_hstate(page);
1541 int nid = page_to_nid(page);
1542 struct hugepage_subpool *spool = hugetlb_page_subpool(page);
1543 bool restore_reserve;
1544 unsigned long flags;
1546 VM_BUG_ON_PAGE(page_count(page), page);
1547 VM_BUG_ON_PAGE(page_mapcount(page), page);
1549 hugetlb_set_page_subpool(page, NULL);
1550 page->mapping = NULL;
1551 restore_reserve = HPageRestoreReserve(page);
1552 ClearHPageRestoreReserve(page);
1555 * If HPageRestoreReserve was set on page, page allocation consumed a
1556 * reservation. If the page was associated with a subpool, there
1557 * would have been a page reserved in the subpool before allocation
1558 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1559 * reservation, do not call hugepage_subpool_put_pages() as this will
1560 * remove the reserved page from the subpool.
1562 if (!restore_reserve) {
1564 * A return code of zero implies that the subpool will be
1565 * under its minimum size if the reservation is not restored
1566 * after page is free. Therefore, force restore_reserve
1569 if (hugepage_subpool_put_pages(spool, 1) == 0)
1570 restore_reserve = true;
1573 spin_lock_irqsave(&hugetlb_lock, flags);
1574 ClearHPageMigratable(page);
1575 hugetlb_cgroup_uncharge_page(hstate_index(h),
1576 pages_per_huge_page(h), page);
1577 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1578 pages_per_huge_page(h), page);
1579 if (restore_reserve)
1580 h->resv_huge_pages++;
1582 if (HPageTemporary(page)) {
1583 remove_hugetlb_page(h, page, false);
1584 spin_unlock_irqrestore(&hugetlb_lock, flags);
1585 update_and_free_page(h, page, true);
1586 } else if (h->surplus_huge_pages_node[nid]) {
1587 /* remove the page from active list */
1588 remove_hugetlb_page(h, page, true);
1589 spin_unlock_irqrestore(&hugetlb_lock, flags);
1590 update_and_free_page(h, page, true);
1592 arch_clear_hugepage_flags(page);
1593 enqueue_huge_page(h, page);
1594 spin_unlock_irqrestore(&hugetlb_lock, flags);
1599 * Must be called with the hugetlb lock held
1601 static void __prep_account_new_huge_page(struct hstate *h, int nid)
1603 lockdep_assert_held(&hugetlb_lock);
1605 h->nr_huge_pages_node[nid]++;
1608 static void __prep_new_huge_page(struct hstate *h, struct page *page)
1610 free_huge_page_vmemmap(h, page);
1611 INIT_LIST_HEAD(&page->lru);
1612 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1613 hugetlb_set_page_subpool(page, NULL);
1614 set_hugetlb_cgroup(page, NULL);
1615 set_hugetlb_cgroup_rsvd(page, NULL);
1618 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1620 __prep_new_huge_page(h, page);
1621 spin_lock_irq(&hugetlb_lock);
1622 __prep_account_new_huge_page(h, nid);
1623 spin_unlock_irq(&hugetlb_lock);
1626 static bool prep_compound_gigantic_page(struct page *page, unsigned int order)
1629 int nr_pages = 1 << order;
1630 struct page *p = page + 1;
1632 /* we rely on prep_new_huge_page to set the destructor */
1633 set_compound_order(page, order);
1634 __ClearPageReserved(page);
1635 __SetPageHead(page);
1636 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1638 * For gigantic hugepages allocated through bootmem at
1639 * boot, it's safer to be consistent with the not-gigantic
1640 * hugepages and clear the PG_reserved bit from all tail pages
1641 * too. Otherwise drivers using get_user_pages() to access tail
1642 * pages may get the reference counting wrong if they see
1643 * PG_reserved set on a tail page (despite the head page not
1644 * having PG_reserved set). Enforcing this consistency between
1645 * head and tail pages allows drivers to optimize away a check
1646 * on the head page when they need know if put_page() is needed
1647 * after get_user_pages().
1649 __ClearPageReserved(p);
1651 * Subtle and very unlikely
1653 * Gigantic 'page allocators' such as memblock or cma will
1654 * return a set of pages with each page ref counted. We need
1655 * to turn this set of pages into a compound page with tail
1656 * page ref counts set to zero. Code such as speculative page
1657 * cache adding could take a ref on a 'to be' tail page.
1658 * We need to respect any increased ref count, and only set
1659 * the ref count to zero if count is currently 1. If count
1660 * is not 1, we call synchronize_rcu in the hope that a rcu
1661 * grace period will cause ref count to drop and then retry.
1662 * If count is still inflated on retry we return an error and
1663 * must discard the pages.
1665 if (!page_ref_freeze(p, 1)) {
1666 pr_info("HugeTLB unexpected inflated ref count on freshly allocated page\n");
1668 if (!page_ref_freeze(p, 1))
1671 set_page_count(p, 0);
1672 set_compound_head(p, page);
1674 atomic_set(compound_mapcount_ptr(page), -1);
1675 atomic_set(compound_pincount_ptr(page), 0);
1679 /* undo tail page modifications made above */
1681 for (j = 1; j < i; j++, p = mem_map_next(p, page, j)) {
1682 clear_compound_head(p);
1683 set_page_refcounted(p);
1685 /* need to clear PG_reserved on remaining tail pages */
1686 for (; j < nr_pages; j++, p = mem_map_next(p, page, j))
1687 __ClearPageReserved(p);
1688 set_compound_order(page, 0);
1689 page[1].compound_nr = 0;
1690 __ClearPageHead(page);
1695 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1696 * transparent huge pages. See the PageTransHuge() documentation for more
1699 int PageHuge(struct page *page)
1701 if (!PageCompound(page))
1704 page = compound_head(page);
1705 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1707 EXPORT_SYMBOL_GPL(PageHuge);
1710 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1711 * normal or transparent huge pages.
1713 int PageHeadHuge(struct page *page_head)
1715 if (!PageHead(page_head))
1718 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1722 * Find and lock address space (mapping) in write mode.
1724 * Upon entry, the page is locked which means that page_mapping() is
1725 * stable. Due to locking order, we can only trylock_write. If we can
1726 * not get the lock, simply return NULL to caller.
1728 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1730 struct address_space *mapping = page_mapping(hpage);
1735 if (i_mmap_trylock_write(mapping))
1741 pgoff_t hugetlb_basepage_index(struct page *page)
1743 struct page *page_head = compound_head(page);
1744 pgoff_t index = page_index(page_head);
1745 unsigned long compound_idx;
1747 if (compound_order(page_head) >= MAX_ORDER)
1748 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1750 compound_idx = page - page_head;
1752 return (index << compound_order(page_head)) + compound_idx;
1755 static struct page *alloc_buddy_huge_page(struct hstate *h,
1756 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1757 nodemask_t *node_alloc_noretry)
1759 int order = huge_page_order(h);
1761 bool alloc_try_hard = true;
1764 * By default we always try hard to allocate the page with
1765 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1766 * a loop (to adjust global huge page counts) and previous allocation
1767 * failed, do not continue to try hard on the same node. Use the
1768 * node_alloc_noretry bitmap to manage this state information.
1770 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1771 alloc_try_hard = false;
1772 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1774 gfp_mask |= __GFP_RETRY_MAYFAIL;
1775 if (nid == NUMA_NO_NODE)
1776 nid = numa_mem_id();
1777 page = __alloc_pages(gfp_mask, order, nid, nmask);
1779 __count_vm_event(HTLB_BUDDY_PGALLOC);
1781 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1784 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1785 * indicates an overall state change. Clear bit so that we resume
1786 * normal 'try hard' allocations.
1788 if (node_alloc_noretry && page && !alloc_try_hard)
1789 node_clear(nid, *node_alloc_noretry);
1792 * If we tried hard to get a page but failed, set bit so that
1793 * subsequent attempts will not try as hard until there is an
1794 * overall state change.
1796 if (node_alloc_noretry && !page && alloc_try_hard)
1797 node_set(nid, *node_alloc_noretry);
1803 * Common helper to allocate a fresh hugetlb page. All specific allocators
1804 * should use this function to get new hugetlb pages
1806 static struct page *alloc_fresh_huge_page(struct hstate *h,
1807 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1808 nodemask_t *node_alloc_noretry)
1814 if (hstate_is_gigantic(h))
1815 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1817 page = alloc_buddy_huge_page(h, gfp_mask,
1818 nid, nmask, node_alloc_noretry);
1822 if (hstate_is_gigantic(h)) {
1823 if (!prep_compound_gigantic_page(page, huge_page_order(h))) {
1825 * Rare failure to convert pages to compound page.
1826 * Free pages and try again - ONCE!
1828 free_gigantic_page(page, huge_page_order(h));
1833 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
1837 prep_new_huge_page(h, page, page_to_nid(page));
1843 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1846 static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1847 nodemask_t *node_alloc_noretry)
1851 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1853 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1854 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1855 node_alloc_noretry);
1863 put_page(page); /* free it into the hugepage allocator */
1869 * Remove huge page from pool from next node to free. Attempt to keep
1870 * persistent huge pages more or less balanced over allowed nodes.
1871 * This routine only 'removes' the hugetlb page. The caller must make
1872 * an additional call to free the page to low level allocators.
1873 * Called with hugetlb_lock locked.
1875 static struct page *remove_pool_huge_page(struct hstate *h,
1876 nodemask_t *nodes_allowed,
1880 struct page *page = NULL;
1882 lockdep_assert_held(&hugetlb_lock);
1883 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1885 * If we're returning unused surplus pages, only examine
1886 * nodes with surplus pages.
1888 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1889 !list_empty(&h->hugepage_freelists[node])) {
1890 page = list_entry(h->hugepage_freelists[node].next,
1892 remove_hugetlb_page(h, page, acct_surplus);
1901 * Dissolve a given free hugepage into free buddy pages. This function does
1902 * nothing for in-use hugepages and non-hugepages.
1903 * This function returns values like below:
1905 * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
1906 * when the system is under memory pressure and the feature of
1907 * freeing unused vmemmap pages associated with each hugetlb page
1909 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1910 * (allocated or reserved.)
1911 * 0: successfully dissolved free hugepages or the page is not a
1912 * hugepage (considered as already dissolved)
1914 int dissolve_free_huge_page(struct page *page)
1919 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1920 if (!PageHuge(page))
1923 spin_lock_irq(&hugetlb_lock);
1924 if (!PageHuge(page)) {
1929 if (!page_count(page)) {
1930 struct page *head = compound_head(page);
1931 struct hstate *h = page_hstate(head);
1932 if (h->free_huge_pages - h->resv_huge_pages == 0)
1936 * We should make sure that the page is already on the free list
1937 * when it is dissolved.
1939 if (unlikely(!HPageFreed(head))) {
1940 spin_unlock_irq(&hugetlb_lock);
1944 * Theoretically, we should return -EBUSY when we
1945 * encounter this race. In fact, we have a chance
1946 * to successfully dissolve the page if we do a
1947 * retry. Because the race window is quite small.
1948 * If we seize this opportunity, it is an optimization
1949 * for increasing the success rate of dissolving page.
1954 remove_hugetlb_page(h, head, false);
1955 h->max_huge_pages--;
1956 spin_unlock_irq(&hugetlb_lock);
1959 * Normally update_and_free_page will allocate required vmemmmap
1960 * before freeing the page. update_and_free_page will fail to
1961 * free the page if it can not allocate required vmemmap. We
1962 * need to adjust max_huge_pages if the page is not freed.
1963 * Attempt to allocate vmemmmap here so that we can take
1964 * appropriate action on failure.
1966 rc = alloc_huge_page_vmemmap(h, head);
1969 * Move PageHWPoison flag from head page to the raw
1970 * error page, which makes any subpages rather than
1971 * the error page reusable.
1973 if (PageHWPoison(head) && page != head) {
1974 SetPageHWPoison(page);
1975 ClearPageHWPoison(head);
1977 update_and_free_page(h, head, false);
1979 spin_lock_irq(&hugetlb_lock);
1980 add_hugetlb_page(h, head, false);
1981 h->max_huge_pages++;
1982 spin_unlock_irq(&hugetlb_lock);
1988 spin_unlock_irq(&hugetlb_lock);
1993 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1994 * make specified memory blocks removable from the system.
1995 * Note that this will dissolve a free gigantic hugepage completely, if any
1996 * part of it lies within the given range.
1997 * Also note that if dissolve_free_huge_page() returns with an error, all
1998 * free hugepages that were dissolved before that error are lost.
2000 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
2006 if (!hugepages_supported())
2009 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
2010 page = pfn_to_page(pfn);
2011 rc = dissolve_free_huge_page(page);
2020 * Allocates a fresh surplus page from the page allocator.
2022 static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
2023 int nid, nodemask_t *nmask)
2025 struct page *page = NULL;
2027 if (hstate_is_gigantic(h))
2030 spin_lock_irq(&hugetlb_lock);
2031 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
2033 spin_unlock_irq(&hugetlb_lock);
2035 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
2039 spin_lock_irq(&hugetlb_lock);
2041 * We could have raced with the pool size change.
2042 * Double check that and simply deallocate the new page
2043 * if we would end up overcommiting the surpluses. Abuse
2044 * temporary page to workaround the nasty free_huge_page
2047 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
2048 SetHPageTemporary(page);
2049 spin_unlock_irq(&hugetlb_lock);
2053 h->surplus_huge_pages++;
2054 h->surplus_huge_pages_node[page_to_nid(page)]++;
2058 spin_unlock_irq(&hugetlb_lock);
2063 static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
2064 int nid, nodemask_t *nmask)
2068 if (hstate_is_gigantic(h))
2071 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
2076 * We do not account these pages as surplus because they are only
2077 * temporary and will be released properly on the last reference
2079 SetHPageTemporary(page);
2085 * Use the VMA's mpolicy to allocate a huge page from the buddy.
2088 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
2089 struct vm_area_struct *vma, unsigned long addr)
2092 struct mempolicy *mpol;
2093 gfp_t gfp_mask = htlb_alloc_mask(h);
2095 nodemask_t *nodemask;
2097 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
2098 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
2099 mpol_cond_put(mpol);
2104 /* page migration callback function */
2105 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
2106 nodemask_t *nmask, gfp_t gfp_mask)
2108 spin_lock_irq(&hugetlb_lock);
2109 if (h->free_huge_pages - h->resv_huge_pages > 0) {
2112 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
2114 spin_unlock_irq(&hugetlb_lock);
2118 spin_unlock_irq(&hugetlb_lock);
2120 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
2123 /* mempolicy aware migration callback */
2124 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
2125 unsigned long address)
2127 struct mempolicy *mpol;
2128 nodemask_t *nodemask;
2133 gfp_mask = htlb_alloc_mask(h);
2134 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
2135 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
2136 mpol_cond_put(mpol);
2142 * Increase the hugetlb pool such that it can accommodate a reservation
2145 static int gather_surplus_pages(struct hstate *h, long delta)
2146 __must_hold(&hugetlb_lock)
2148 struct list_head surplus_list;
2149 struct page *page, *tmp;
2152 long needed, allocated;
2153 bool alloc_ok = true;
2155 lockdep_assert_held(&hugetlb_lock);
2156 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2158 h->resv_huge_pages += delta;
2163 INIT_LIST_HEAD(&surplus_list);
2167 spin_unlock_irq(&hugetlb_lock);
2168 for (i = 0; i < needed; i++) {
2169 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2170 NUMA_NO_NODE, NULL);
2175 list_add(&page->lru, &surplus_list);
2181 * After retaking hugetlb_lock, we need to recalculate 'needed'
2182 * because either resv_huge_pages or free_huge_pages may have changed.
2184 spin_lock_irq(&hugetlb_lock);
2185 needed = (h->resv_huge_pages + delta) -
2186 (h->free_huge_pages + allocated);
2191 * We were not able to allocate enough pages to
2192 * satisfy the entire reservation so we free what
2193 * we've allocated so far.
2198 * The surplus_list now contains _at_least_ the number of extra pages
2199 * needed to accommodate the reservation. Add the appropriate number
2200 * of pages to the hugetlb pool and free the extras back to the buddy
2201 * allocator. Commit the entire reservation here to prevent another
2202 * process from stealing the pages as they are added to the pool but
2203 * before they are reserved.
2205 needed += allocated;
2206 h->resv_huge_pages += delta;
2209 /* Free the needed pages to the hugetlb pool */
2210 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2216 * This page is now managed by the hugetlb allocator and has
2217 * no users -- drop the buddy allocator's reference.
2219 zeroed = put_page_testzero(page);
2220 VM_BUG_ON_PAGE(!zeroed, page);
2221 enqueue_huge_page(h, page);
2224 spin_unlock_irq(&hugetlb_lock);
2226 /* Free unnecessary surplus pages to the buddy allocator */
2227 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2229 spin_lock_irq(&hugetlb_lock);
2235 * This routine has two main purposes:
2236 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2237 * in unused_resv_pages. This corresponds to the prior adjustments made
2238 * to the associated reservation map.
2239 * 2) Free any unused surplus pages that may have been allocated to satisfy
2240 * the reservation. As many as unused_resv_pages may be freed.
2242 static void return_unused_surplus_pages(struct hstate *h,
2243 unsigned long unused_resv_pages)
2245 unsigned long nr_pages;
2247 LIST_HEAD(page_list);
2249 lockdep_assert_held(&hugetlb_lock);
2250 /* Uncommit the reservation */
2251 h->resv_huge_pages -= unused_resv_pages;
2253 /* Cannot return gigantic pages currently */
2254 if (hstate_is_gigantic(h))
2258 * Part (or even all) of the reservation could have been backed
2259 * by pre-allocated pages. Only free surplus pages.
2261 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2264 * We want to release as many surplus pages as possible, spread
2265 * evenly across all nodes with memory. Iterate across these nodes
2266 * until we can no longer free unreserved surplus pages. This occurs
2267 * when the nodes with surplus pages have no free pages.
2268 * remove_pool_huge_page() will balance the freed pages across the
2269 * on-line nodes with memory and will handle the hstate accounting.
2271 while (nr_pages--) {
2272 page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1);
2276 list_add(&page->lru, &page_list);
2280 spin_unlock_irq(&hugetlb_lock);
2281 update_and_free_pages_bulk(h, &page_list);
2282 spin_lock_irq(&hugetlb_lock);
2287 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2288 * are used by the huge page allocation routines to manage reservations.
2290 * vma_needs_reservation is called to determine if the huge page at addr
2291 * within the vma has an associated reservation. If a reservation is
2292 * needed, the value 1 is returned. The caller is then responsible for
2293 * managing the global reservation and subpool usage counts. After
2294 * the huge page has been allocated, vma_commit_reservation is called
2295 * to add the page to the reservation map. If the page allocation fails,
2296 * the reservation must be ended instead of committed. vma_end_reservation
2297 * is called in such cases.
2299 * In the normal case, vma_commit_reservation returns the same value
2300 * as the preceding vma_needs_reservation call. The only time this
2301 * is not the case is if a reserve map was changed between calls. It
2302 * is the responsibility of the caller to notice the difference and
2303 * take appropriate action.
2305 * vma_add_reservation is used in error paths where a reservation must
2306 * be restored when a newly allocated huge page must be freed. It is
2307 * to be called after calling vma_needs_reservation to determine if a
2308 * reservation exists.
2310 * vma_del_reservation is used in error paths where an entry in the reserve
2311 * map was created during huge page allocation and must be removed. It is to
2312 * be called after calling vma_needs_reservation to determine if a reservation
2315 enum vma_resv_mode {
2322 static long __vma_reservation_common(struct hstate *h,
2323 struct vm_area_struct *vma, unsigned long addr,
2324 enum vma_resv_mode mode)
2326 struct resv_map *resv;
2329 long dummy_out_regions_needed;
2331 resv = vma_resv_map(vma);
2335 idx = vma_hugecache_offset(h, vma, addr);
2337 case VMA_NEEDS_RESV:
2338 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2339 /* We assume that vma_reservation_* routines always operate on
2340 * 1 page, and that adding to resv map a 1 page entry can only
2341 * ever require 1 region.
2343 VM_BUG_ON(dummy_out_regions_needed != 1);
2345 case VMA_COMMIT_RESV:
2346 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2347 /* region_add calls of range 1 should never fail. */
2351 region_abort(resv, idx, idx + 1, 1);
2355 if (vma->vm_flags & VM_MAYSHARE) {
2356 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2357 /* region_add calls of range 1 should never fail. */
2360 region_abort(resv, idx, idx + 1, 1);
2361 ret = region_del(resv, idx, idx + 1);
2365 if (vma->vm_flags & VM_MAYSHARE) {
2366 region_abort(resv, idx, idx + 1, 1);
2367 ret = region_del(resv, idx, idx + 1);
2369 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2370 /* region_add calls of range 1 should never fail. */
2378 if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV)
2381 * We know private mapping must have HPAGE_RESV_OWNER set.
2383 * In most cases, reserves always exist for private mappings.
2384 * However, a file associated with mapping could have been
2385 * hole punched or truncated after reserves were consumed.
2386 * As subsequent fault on such a range will not use reserves.
2387 * Subtle - The reserve map for private mappings has the
2388 * opposite meaning than that of shared mappings. If NO
2389 * entry is in the reserve map, it means a reservation exists.
2390 * If an entry exists in the reserve map, it means the
2391 * reservation has already been consumed. As a result, the
2392 * return value of this routine is the opposite of the
2393 * value returned from reserve map manipulation routines above.
2402 static long vma_needs_reservation(struct hstate *h,
2403 struct vm_area_struct *vma, unsigned long addr)
2405 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2408 static long vma_commit_reservation(struct hstate *h,
2409 struct vm_area_struct *vma, unsigned long addr)
2411 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2414 static void vma_end_reservation(struct hstate *h,
2415 struct vm_area_struct *vma, unsigned long addr)
2417 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2420 static long vma_add_reservation(struct hstate *h,
2421 struct vm_area_struct *vma, unsigned long addr)
2423 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2426 static long vma_del_reservation(struct hstate *h,
2427 struct vm_area_struct *vma, unsigned long addr)
2429 return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV);
2433 * This routine is called to restore reservation information on error paths.
2434 * It should ONLY be called for pages allocated via alloc_huge_page(), and
2435 * the hugetlb mutex should remain held when calling this routine.
2437 * It handles two specific cases:
2438 * 1) A reservation was in place and the page consumed the reservation.
2439 * HPageRestoreReserve is set in the page.
2440 * 2) No reservation was in place for the page, so HPageRestoreReserve is
2441 * not set. However, alloc_huge_page always updates the reserve map.
2443 * In case 1, free_huge_page later in the error path will increment the
2444 * global reserve count. But, free_huge_page does not have enough context
2445 * to adjust the reservation map. This case deals primarily with private
2446 * mappings. Adjust the reserve map here to be consistent with global
2447 * reserve count adjustments to be made by free_huge_page. Make sure the
2448 * reserve map indicates there is a reservation present.
2450 * In case 2, simply undo reserve map modifications done by alloc_huge_page.
2452 void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
2453 unsigned long address, struct page *page)
2455 long rc = vma_needs_reservation(h, vma, address);
2457 if (HPageRestoreReserve(page)) {
2458 if (unlikely(rc < 0))
2460 * Rare out of memory condition in reserve map
2461 * manipulation. Clear HPageRestoreReserve so that
2462 * global reserve count will not be incremented
2463 * by free_huge_page. This will make it appear
2464 * as though the reservation for this page was
2465 * consumed. This may prevent the task from
2466 * faulting in the page at a later time. This
2467 * is better than inconsistent global huge page
2468 * accounting of reserve counts.
2470 ClearHPageRestoreReserve(page);
2472 (void)vma_add_reservation(h, vma, address);
2474 vma_end_reservation(h, vma, address);
2478 * This indicates there is an entry in the reserve map
2479 * added by alloc_huge_page. We know it was added
2480 * before the alloc_huge_page call, otherwise
2481 * HPageRestoreReserve would be set on the page.
2482 * Remove the entry so that a subsequent allocation
2483 * does not consume a reservation.
2485 rc = vma_del_reservation(h, vma, address);
2488 * VERY rare out of memory condition. Since
2489 * we can not delete the entry, set
2490 * HPageRestoreReserve so that the reserve
2491 * count will be incremented when the page
2492 * is freed. This reserve will be consumed
2493 * on a subsequent allocation.
2495 SetHPageRestoreReserve(page);
2496 } else if (rc < 0) {
2498 * Rare out of memory condition from
2499 * vma_needs_reservation call. Memory allocation is
2500 * only attempted if a new entry is needed. Therefore,
2501 * this implies there is not an entry in the
2504 * For shared mappings, no entry in the map indicates
2505 * no reservation. We are done.
2507 if (!(vma->vm_flags & VM_MAYSHARE))
2509 * For private mappings, no entry indicates
2510 * a reservation is present. Since we can
2511 * not add an entry, set SetHPageRestoreReserve
2512 * on the page so reserve count will be
2513 * incremented when freed. This reserve will
2514 * be consumed on a subsequent allocation.
2516 SetHPageRestoreReserve(page);
2519 * No reservation present, do nothing
2521 vma_end_reservation(h, vma, address);
2526 * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one
2527 * @h: struct hstate old page belongs to
2528 * @old_page: Old page to dissolve
2529 * @list: List to isolate the page in case we need to
2530 * Returns 0 on success, otherwise negated error.
2532 static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
2533 struct list_head *list)
2535 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2536 int nid = page_to_nid(old_page);
2537 struct page *new_page;
2541 * Before dissolving the page, we need to allocate a new one for the
2542 * pool to remain stable. Here, we allocate the page and 'prep' it
2543 * by doing everything but actually updating counters and adding to
2544 * the pool. This simplifies and let us do most of the processing
2547 new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
2550 __prep_new_huge_page(h, new_page);
2553 spin_lock_irq(&hugetlb_lock);
2554 if (!PageHuge(old_page)) {
2556 * Freed from under us. Drop new_page too.
2559 } else if (page_count(old_page)) {
2561 * Someone has grabbed the page, try to isolate it here.
2562 * Fail with -EBUSY if not possible.
2564 spin_unlock_irq(&hugetlb_lock);
2565 if (!isolate_huge_page(old_page, list))
2567 spin_lock_irq(&hugetlb_lock);
2569 } else if (!HPageFreed(old_page)) {
2571 * Page's refcount is 0 but it has not been enqueued in the
2572 * freelist yet. Race window is small, so we can succeed here if
2575 spin_unlock_irq(&hugetlb_lock);
2580 * Ok, old_page is still a genuine free hugepage. Remove it from
2581 * the freelist and decrease the counters. These will be
2582 * incremented again when calling __prep_account_new_huge_page()
2583 * and enqueue_huge_page() for new_page. The counters will remain
2584 * stable since this happens under the lock.
2586 remove_hugetlb_page(h, old_page, false);
2589 * Reference count trick is needed because allocator gives us
2590 * referenced page but the pool requires pages with 0 refcount.
2592 __prep_account_new_huge_page(h, nid);
2593 page_ref_dec(new_page);
2594 enqueue_huge_page(h, new_page);
2597 * Pages have been replaced, we can safely free the old one.
2599 spin_unlock_irq(&hugetlb_lock);
2600 update_and_free_page(h, old_page, false);
2606 spin_unlock_irq(&hugetlb_lock);
2607 update_and_free_page(h, new_page, false);
2612 int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
2619 * The page might have been dissolved from under our feet, so make sure
2620 * to carefully check the state under the lock.
2621 * Return success when racing as if we dissolved the page ourselves.
2623 spin_lock_irq(&hugetlb_lock);
2624 if (PageHuge(page)) {
2625 head = compound_head(page);
2626 h = page_hstate(head);
2628 spin_unlock_irq(&hugetlb_lock);
2631 spin_unlock_irq(&hugetlb_lock);
2634 * Fence off gigantic pages as there is a cyclic dependency between
2635 * alloc_contig_range and them. Return -ENOMEM as this has the effect
2636 * of bailing out right away without further retrying.
2638 if (hstate_is_gigantic(h))
2641 if (page_count(head) && isolate_huge_page(head, list))
2643 else if (!page_count(head))
2644 ret = alloc_and_dissolve_huge_page(h, head, list);
2649 struct page *alloc_huge_page(struct vm_area_struct *vma,
2650 unsigned long addr, int avoid_reserve)
2652 struct hugepage_subpool *spool = subpool_vma(vma);
2653 struct hstate *h = hstate_vma(vma);
2655 long map_chg, map_commit;
2658 struct hugetlb_cgroup *h_cg;
2659 bool deferred_reserve;
2661 idx = hstate_index(h);
2663 * Examine the region/reserve map to determine if the process
2664 * has a reservation for the page to be allocated. A return
2665 * code of zero indicates a reservation exists (no change).
2667 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2669 return ERR_PTR(-ENOMEM);
2672 * Processes that did not create the mapping will have no
2673 * reserves as indicated by the region/reserve map. Check
2674 * that the allocation will not exceed the subpool limit.
2675 * Allocations for MAP_NORESERVE mappings also need to be
2676 * checked against any subpool limit.
2678 if (map_chg || avoid_reserve) {
2679 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2681 vma_end_reservation(h, vma, addr);
2682 return ERR_PTR(-ENOSPC);
2686 * Even though there was no reservation in the region/reserve
2687 * map, there could be reservations associated with the
2688 * subpool that can be used. This would be indicated if the
2689 * return value of hugepage_subpool_get_pages() is zero.
2690 * However, if avoid_reserve is specified we still avoid even
2691 * the subpool reservations.
2697 /* If this allocation is not consuming a reservation, charge it now.
2699 deferred_reserve = map_chg || avoid_reserve;
2700 if (deferred_reserve) {
2701 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2702 idx, pages_per_huge_page(h), &h_cg);
2704 goto out_subpool_put;
2707 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2709 goto out_uncharge_cgroup_reservation;
2711 spin_lock_irq(&hugetlb_lock);
2713 * glb_chg is passed to indicate whether or not a page must be taken
2714 * from the global free pool (global change). gbl_chg == 0 indicates
2715 * a reservation exists for the allocation.
2717 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2719 spin_unlock_irq(&hugetlb_lock);
2720 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2722 goto out_uncharge_cgroup;
2723 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2724 SetHPageRestoreReserve(page);
2725 h->resv_huge_pages--;
2727 spin_lock_irq(&hugetlb_lock);
2728 list_add(&page->lru, &h->hugepage_activelist);
2731 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2732 /* If allocation is not consuming a reservation, also store the
2733 * hugetlb_cgroup pointer on the page.
2735 if (deferred_reserve) {
2736 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2740 spin_unlock_irq(&hugetlb_lock);
2742 hugetlb_set_page_subpool(page, spool);
2744 map_commit = vma_commit_reservation(h, vma, addr);
2745 if (unlikely(map_chg > map_commit)) {
2747 * The page was added to the reservation map between
2748 * vma_needs_reservation and vma_commit_reservation.
2749 * This indicates a race with hugetlb_reserve_pages.
2750 * Adjust for the subpool count incremented above AND
2751 * in hugetlb_reserve_pages for the same page. Also,
2752 * the reservation count added in hugetlb_reserve_pages
2753 * no longer applies.
2757 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2758 hugetlb_acct_memory(h, -rsv_adjust);
2759 if (deferred_reserve)
2760 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2761 pages_per_huge_page(h), page);
2765 out_uncharge_cgroup:
2766 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2767 out_uncharge_cgroup_reservation:
2768 if (deferred_reserve)
2769 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2772 if (map_chg || avoid_reserve)
2773 hugepage_subpool_put_pages(spool, 1);
2774 vma_end_reservation(h, vma, addr);
2775 return ERR_PTR(-ENOSPC);
2778 int alloc_bootmem_huge_page(struct hstate *h)
2779 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2780 int __alloc_bootmem_huge_page(struct hstate *h)
2782 struct huge_bootmem_page *m;
2785 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2788 addr = memblock_alloc_try_nid_raw(
2789 huge_page_size(h), huge_page_size(h),
2790 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2793 * Use the beginning of the huge page to store the
2794 * huge_bootmem_page struct (until gather_bootmem
2795 * puts them into the mem_map).
2804 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2805 /* Put them into a private list first because mem_map is not up yet */
2806 INIT_LIST_HEAD(&m->list);
2807 list_add(&m->list, &huge_boot_pages);
2813 * Put bootmem huge pages into the standard lists after mem_map is up.
2814 * Note: This only applies to gigantic (order > MAX_ORDER) pages.
2816 static void __init gather_bootmem_prealloc(void)
2818 struct huge_bootmem_page *m;
2820 list_for_each_entry(m, &huge_boot_pages, list) {
2821 struct page *page = virt_to_page(m);
2822 struct hstate *h = m->hstate;
2824 VM_BUG_ON(!hstate_is_gigantic(h));
2825 WARN_ON(page_count(page) != 1);
2826 if (prep_compound_gigantic_page(page, huge_page_order(h))) {
2827 WARN_ON(PageReserved(page));
2828 prep_new_huge_page(h, page, page_to_nid(page));
2829 put_page(page); /* add to the hugepage allocator */
2831 free_gigantic_page(page, huge_page_order(h));
2832 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
2836 * We need to restore the 'stolen' pages to totalram_pages
2837 * in order to fix confusing memory reports from free(1) and
2838 * other side-effects, like CommitLimit going negative.
2840 adjust_managed_page_count(page, pages_per_huge_page(h));
2845 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2848 nodemask_t *node_alloc_noretry;
2850 if (!hstate_is_gigantic(h)) {
2852 * Bit mask controlling how hard we retry per-node allocations.
2853 * Ignore errors as lower level routines can deal with
2854 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2855 * time, we are likely in bigger trouble.
2857 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2860 /* allocations done at boot time */
2861 node_alloc_noretry = NULL;
2864 /* bit mask controlling how hard we retry per-node allocations */
2865 if (node_alloc_noretry)
2866 nodes_clear(*node_alloc_noretry);
2868 for (i = 0; i < h->max_huge_pages; ++i) {
2869 if (hstate_is_gigantic(h)) {
2870 if (hugetlb_cma_size) {
2871 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2874 if (!alloc_bootmem_huge_page(h))
2876 } else if (!alloc_pool_huge_page(h,
2877 &node_states[N_MEMORY],
2878 node_alloc_noretry))
2882 if (i < h->max_huge_pages) {
2885 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2886 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2887 h->max_huge_pages, buf, i);
2888 h->max_huge_pages = i;
2891 kfree(node_alloc_noretry);
2894 static void __init hugetlb_init_hstates(void)
2898 for_each_hstate(h) {
2899 if (minimum_order > huge_page_order(h))
2900 minimum_order = huge_page_order(h);
2902 /* oversize hugepages were init'ed in early boot */
2903 if (!hstate_is_gigantic(h))
2904 hugetlb_hstate_alloc_pages(h);
2906 VM_BUG_ON(minimum_order == UINT_MAX);
2909 static void __init report_hugepages(void)
2913 for_each_hstate(h) {
2916 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2917 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2918 buf, h->free_huge_pages);
2922 #ifdef CONFIG_HIGHMEM
2923 static void try_to_free_low(struct hstate *h, unsigned long count,
2924 nodemask_t *nodes_allowed)
2927 LIST_HEAD(page_list);
2929 lockdep_assert_held(&hugetlb_lock);
2930 if (hstate_is_gigantic(h))
2934 * Collect pages to be freed on a list, and free after dropping lock
2936 for_each_node_mask(i, *nodes_allowed) {
2937 struct page *page, *next;
2938 struct list_head *freel = &h->hugepage_freelists[i];
2939 list_for_each_entry_safe(page, next, freel, lru) {
2940 if (count >= h->nr_huge_pages)
2942 if (PageHighMem(page))
2944 remove_hugetlb_page(h, page, false);
2945 list_add(&page->lru, &page_list);
2950 spin_unlock_irq(&hugetlb_lock);
2951 update_and_free_pages_bulk(h, &page_list);
2952 spin_lock_irq(&hugetlb_lock);
2955 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2956 nodemask_t *nodes_allowed)
2962 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2963 * balanced by operating on them in a round-robin fashion.
2964 * Returns 1 if an adjustment was made.
2966 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2971 lockdep_assert_held(&hugetlb_lock);
2972 VM_BUG_ON(delta != -1 && delta != 1);
2975 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2976 if (h->surplus_huge_pages_node[node])
2980 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2981 if (h->surplus_huge_pages_node[node] <
2982 h->nr_huge_pages_node[node])
2989 h->surplus_huge_pages += delta;
2990 h->surplus_huge_pages_node[node] += delta;
2994 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2995 static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2996 nodemask_t *nodes_allowed)
2998 unsigned long min_count, ret;
3000 LIST_HEAD(page_list);
3001 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
3004 * Bit mask controlling how hard we retry per-node allocations.
3005 * If we can not allocate the bit mask, do not attempt to allocate
3006 * the requested huge pages.
3008 if (node_alloc_noretry)
3009 nodes_clear(*node_alloc_noretry);
3014 * resize_lock mutex prevents concurrent adjustments to number of
3015 * pages in hstate via the proc/sysfs interfaces.
3017 mutex_lock(&h->resize_lock);
3018 flush_free_hpage_work(h);
3019 spin_lock_irq(&hugetlb_lock);
3022 * Check for a node specific request.
3023 * Changing node specific huge page count may require a corresponding
3024 * change to the global count. In any case, the passed node mask
3025 * (nodes_allowed) will restrict alloc/free to the specified node.
3027 if (nid != NUMA_NO_NODE) {
3028 unsigned long old_count = count;
3030 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
3032 * User may have specified a large count value which caused the
3033 * above calculation to overflow. In this case, they wanted
3034 * to allocate as many huge pages as possible. Set count to
3035 * largest possible value to align with their intention.
3037 if (count < old_count)
3042 * Gigantic pages runtime allocation depend on the capability for large
3043 * page range allocation.
3044 * If the system does not provide this feature, return an error when
3045 * the user tries to allocate gigantic pages but let the user free the
3046 * boottime allocated gigantic pages.
3048 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
3049 if (count > persistent_huge_pages(h)) {
3050 spin_unlock_irq(&hugetlb_lock);
3051 mutex_unlock(&h->resize_lock);
3052 NODEMASK_FREE(node_alloc_noretry);
3055 /* Fall through to decrease pool */
3059 * Increase the pool size
3060 * First take pages out of surplus state. Then make up the
3061 * remaining difference by allocating fresh huge pages.
3063 * We might race with alloc_surplus_huge_page() here and be unable
3064 * to convert a surplus huge page to a normal huge page. That is
3065 * not critical, though, it just means the overall size of the
3066 * pool might be one hugepage larger than it needs to be, but
3067 * within all the constraints specified by the sysctls.
3069 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
3070 if (!adjust_pool_surplus(h, nodes_allowed, -1))
3074 while (count > persistent_huge_pages(h)) {
3076 * If this allocation races such that we no longer need the
3077 * page, free_huge_page will handle it by freeing the page
3078 * and reducing the surplus.
3080 spin_unlock_irq(&hugetlb_lock);
3082 /* yield cpu to avoid soft lockup */
3085 ret = alloc_pool_huge_page(h, nodes_allowed,
3086 node_alloc_noretry);
3087 spin_lock_irq(&hugetlb_lock);
3091 /* Bail for signals. Probably ctrl-c from user */
3092 if (signal_pending(current))
3097 * Decrease the pool size
3098 * First return free pages to the buddy allocator (being careful
3099 * to keep enough around to satisfy reservations). Then place
3100 * pages into surplus state as needed so the pool will shrink
3101 * to the desired size as pages become free.
3103 * By placing pages into the surplus state independent of the
3104 * overcommit value, we are allowing the surplus pool size to
3105 * exceed overcommit. There are few sane options here. Since
3106 * alloc_surplus_huge_page() is checking the global counter,
3107 * though, we'll note that we're not allowed to exceed surplus
3108 * and won't grow the pool anywhere else. Not until one of the
3109 * sysctls are changed, or the surplus pages go out of use.
3111 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
3112 min_count = max(count, min_count);
3113 try_to_free_low(h, min_count, nodes_allowed);
3116 * Collect pages to be removed on list without dropping lock
3118 while (min_count < persistent_huge_pages(h)) {
3119 page = remove_pool_huge_page(h, nodes_allowed, 0);
3123 list_add(&page->lru, &page_list);
3125 /* free the pages after dropping lock */
3126 spin_unlock_irq(&hugetlb_lock);
3127 update_and_free_pages_bulk(h, &page_list);
3128 flush_free_hpage_work(h);
3129 spin_lock_irq(&hugetlb_lock);
3131 while (count < persistent_huge_pages(h)) {
3132 if (!adjust_pool_surplus(h, nodes_allowed, 1))
3136 h->max_huge_pages = persistent_huge_pages(h);
3137 spin_unlock_irq(&hugetlb_lock);
3138 mutex_unlock(&h->resize_lock);
3140 NODEMASK_FREE(node_alloc_noretry);
3145 #define HSTATE_ATTR_RO(_name) \
3146 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
3148 #define HSTATE_ATTR(_name) \
3149 static struct kobj_attribute _name##_attr = \
3150 __ATTR(_name, 0644, _name##_show, _name##_store)
3152 static struct kobject *hugepages_kobj;
3153 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3155 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
3157 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
3161 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3162 if (hstate_kobjs[i] == kobj) {
3164 *nidp = NUMA_NO_NODE;
3168 return kobj_to_node_hstate(kobj, nidp);
3171 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
3172 struct kobj_attribute *attr, char *buf)
3175 unsigned long nr_huge_pages;
3178 h = kobj_to_hstate(kobj, &nid);
3179 if (nid == NUMA_NO_NODE)
3180 nr_huge_pages = h->nr_huge_pages;
3182 nr_huge_pages = h->nr_huge_pages_node[nid];
3184 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
3187 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
3188 struct hstate *h, int nid,
3189 unsigned long count, size_t len)
3192 nodemask_t nodes_allowed, *n_mask;
3194 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
3197 if (nid == NUMA_NO_NODE) {
3199 * global hstate attribute
3201 if (!(obey_mempolicy &&
3202 init_nodemask_of_mempolicy(&nodes_allowed)))
3203 n_mask = &node_states[N_MEMORY];
3205 n_mask = &nodes_allowed;
3208 * Node specific request. count adjustment happens in
3209 * set_max_huge_pages() after acquiring hugetlb_lock.
3211 init_nodemask_of_node(&nodes_allowed, nid);
3212 n_mask = &nodes_allowed;
3215 err = set_max_huge_pages(h, count, nid, n_mask);
3217 return err ? err : len;
3220 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
3221 struct kobject *kobj, const char *buf,
3225 unsigned long count;
3229 err = kstrtoul(buf, 10, &count);
3233 h = kobj_to_hstate(kobj, &nid);
3234 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
3237 static ssize_t nr_hugepages_show(struct kobject *kobj,
3238 struct kobj_attribute *attr, char *buf)
3240 return nr_hugepages_show_common(kobj, attr, buf);
3243 static ssize_t nr_hugepages_store(struct kobject *kobj,
3244 struct kobj_attribute *attr, const char *buf, size_t len)
3246 return nr_hugepages_store_common(false, kobj, buf, len);
3248 HSTATE_ATTR(nr_hugepages);
3253 * hstate attribute for optionally mempolicy-based constraint on persistent
3254 * huge page alloc/free.
3256 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
3257 struct kobj_attribute *attr,
3260 return nr_hugepages_show_common(kobj, attr, buf);
3263 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
3264 struct kobj_attribute *attr, const char *buf, size_t len)
3266 return nr_hugepages_store_common(true, kobj, buf, len);
3268 HSTATE_ATTR(nr_hugepages_mempolicy);
3272 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
3273 struct kobj_attribute *attr, char *buf)
3275 struct hstate *h = kobj_to_hstate(kobj, NULL);
3276 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
3279 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
3280 struct kobj_attribute *attr, const char *buf, size_t count)
3283 unsigned long input;
3284 struct hstate *h = kobj_to_hstate(kobj, NULL);
3286 if (hstate_is_gigantic(h))
3289 err = kstrtoul(buf, 10, &input);
3293 spin_lock_irq(&hugetlb_lock);
3294 h->nr_overcommit_huge_pages = input;
3295 spin_unlock_irq(&hugetlb_lock);
3299 HSTATE_ATTR(nr_overcommit_hugepages);
3301 static ssize_t free_hugepages_show(struct kobject *kobj,
3302 struct kobj_attribute *attr, char *buf)
3305 unsigned long free_huge_pages;
3308 h = kobj_to_hstate(kobj, &nid);
3309 if (nid == NUMA_NO_NODE)
3310 free_huge_pages = h->free_huge_pages;
3312 free_huge_pages = h->free_huge_pages_node[nid];
3314 return sysfs_emit(buf, "%lu\n", free_huge_pages);
3316 HSTATE_ATTR_RO(free_hugepages);
3318 static ssize_t resv_hugepages_show(struct kobject *kobj,
3319 struct kobj_attribute *attr, char *buf)
3321 struct hstate *h = kobj_to_hstate(kobj, NULL);
3322 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
3324 HSTATE_ATTR_RO(resv_hugepages);
3326 static ssize_t surplus_hugepages_show(struct kobject *kobj,
3327 struct kobj_attribute *attr, char *buf)
3330 unsigned long surplus_huge_pages;
3333 h = kobj_to_hstate(kobj, &nid);
3334 if (nid == NUMA_NO_NODE)
3335 surplus_huge_pages = h->surplus_huge_pages;
3337 surplus_huge_pages = h->surplus_huge_pages_node[nid];
3339 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
3341 HSTATE_ATTR_RO(surplus_hugepages);
3343 static struct attribute *hstate_attrs[] = {
3344 &nr_hugepages_attr.attr,
3345 &nr_overcommit_hugepages_attr.attr,
3346 &free_hugepages_attr.attr,
3347 &resv_hugepages_attr.attr,
3348 &surplus_hugepages_attr.attr,
3350 &nr_hugepages_mempolicy_attr.attr,
3355 static const struct attribute_group hstate_attr_group = {
3356 .attrs = hstate_attrs,
3359 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
3360 struct kobject **hstate_kobjs,
3361 const struct attribute_group *hstate_attr_group)
3364 int hi = hstate_index(h);
3366 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3367 if (!hstate_kobjs[hi])
3370 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3372 kobject_put(hstate_kobjs[hi]);
3373 hstate_kobjs[hi] = NULL;
3379 static void __init hugetlb_sysfs_init(void)
3384 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3385 if (!hugepages_kobj)
3388 for_each_hstate(h) {
3389 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3390 hstate_kobjs, &hstate_attr_group);
3392 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3399 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3400 * with node devices in node_devices[] using a parallel array. The array
3401 * index of a node device or _hstate == node id.
3402 * This is here to avoid any static dependency of the node device driver, in
3403 * the base kernel, on the hugetlb module.
3405 struct node_hstate {
3406 struct kobject *hugepages_kobj;
3407 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3409 static struct node_hstate node_hstates[MAX_NUMNODES];
3412 * A subset of global hstate attributes for node devices
3414 static struct attribute *per_node_hstate_attrs[] = {
3415 &nr_hugepages_attr.attr,
3416 &free_hugepages_attr.attr,
3417 &surplus_hugepages_attr.attr,
3421 static const struct attribute_group per_node_hstate_attr_group = {
3422 .attrs = per_node_hstate_attrs,
3426 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3427 * Returns node id via non-NULL nidp.
3429 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3433 for (nid = 0; nid < nr_node_ids; nid++) {
3434 struct node_hstate *nhs = &node_hstates[nid];
3436 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3437 if (nhs->hstate_kobjs[i] == kobj) {
3449 * Unregister hstate attributes from a single node device.
3450 * No-op if no hstate attributes attached.
3452 static void hugetlb_unregister_node(struct node *node)
3455 struct node_hstate *nhs = &node_hstates[node->dev.id];
3457 if (!nhs->hugepages_kobj)
3458 return; /* no hstate attributes */
3460 for_each_hstate(h) {
3461 int idx = hstate_index(h);
3462 if (nhs->hstate_kobjs[idx]) {
3463 kobject_put(nhs->hstate_kobjs[idx]);
3464 nhs->hstate_kobjs[idx] = NULL;
3468 kobject_put(nhs->hugepages_kobj);
3469 nhs->hugepages_kobj = NULL;
3474 * Register hstate attributes for a single node device.
3475 * No-op if attributes already registered.
3477 static void hugetlb_register_node(struct node *node)
3480 struct node_hstate *nhs = &node_hstates[node->dev.id];
3483 if (nhs->hugepages_kobj)
3484 return; /* already allocated */
3486 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3488 if (!nhs->hugepages_kobj)
3491 for_each_hstate(h) {
3492 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3494 &per_node_hstate_attr_group);
3496 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3497 h->name, node->dev.id);
3498 hugetlb_unregister_node(node);
3505 * hugetlb init time: register hstate attributes for all registered node
3506 * devices of nodes that have memory. All on-line nodes should have
3507 * registered their associated device by this time.
3509 static void __init hugetlb_register_all_nodes(void)
3513 for_each_node_state(nid, N_MEMORY) {
3514 struct node *node = node_devices[nid];
3515 if (node->dev.id == nid)
3516 hugetlb_register_node(node);
3520 * Let the node device driver know we're here so it can
3521 * [un]register hstate attributes on node hotplug.
3523 register_hugetlbfs_with_node(hugetlb_register_node,
3524 hugetlb_unregister_node);
3526 #else /* !CONFIG_NUMA */
3528 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3536 static void hugetlb_register_all_nodes(void) { }
3540 static int __init hugetlb_init(void)
3544 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3547 if (!hugepages_supported()) {
3548 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3549 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3554 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3555 * architectures depend on setup being done here.
3557 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3558 if (!parsed_default_hugepagesz) {
3560 * If we did not parse a default huge page size, set
3561 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3562 * number of huge pages for this default size was implicitly
3563 * specified, set that here as well.
3564 * Note that the implicit setting will overwrite an explicit
3565 * setting. A warning will be printed in this case.
3567 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3568 if (default_hstate_max_huge_pages) {
3569 if (default_hstate.max_huge_pages) {
3572 string_get_size(huge_page_size(&default_hstate),
3573 1, STRING_UNITS_2, buf, 32);
3574 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3575 default_hstate.max_huge_pages, buf);
3576 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3577 default_hstate_max_huge_pages);
3579 default_hstate.max_huge_pages =
3580 default_hstate_max_huge_pages;
3584 hugetlb_cma_check();
3585 hugetlb_init_hstates();
3586 gather_bootmem_prealloc();
3589 hugetlb_sysfs_init();
3590 hugetlb_register_all_nodes();
3591 hugetlb_cgroup_file_init();
3594 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3596 num_fault_mutexes = 1;
3598 hugetlb_fault_mutex_table =
3599 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3601 BUG_ON(!hugetlb_fault_mutex_table);
3603 for (i = 0; i < num_fault_mutexes; i++)
3604 mutex_init(&hugetlb_fault_mutex_table[i]);
3607 subsys_initcall(hugetlb_init);
3609 /* Overwritten by architectures with more huge page sizes */
3610 bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3612 return size == HPAGE_SIZE;
3615 void __init hugetlb_add_hstate(unsigned int order)
3620 if (size_to_hstate(PAGE_SIZE << order)) {
3623 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3625 h = &hstates[hugetlb_max_hstate++];
3626 mutex_init(&h->resize_lock);
3628 h->mask = ~(huge_page_size(h) - 1);
3629 for (i = 0; i < MAX_NUMNODES; ++i)
3630 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3631 INIT_LIST_HEAD(&h->hugepage_activelist);
3632 h->next_nid_to_alloc = first_memory_node;
3633 h->next_nid_to_free = first_memory_node;
3634 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3635 huge_page_size(h)/1024);
3636 hugetlb_vmemmap_init(h);
3642 * hugepages command line processing
3643 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3644 * specification. If not, ignore the hugepages value. hugepages can also
3645 * be the first huge page command line option in which case it implicitly
3646 * specifies the number of huge pages for the default size.
3648 static int __init hugepages_setup(char *s)
3651 static unsigned long *last_mhp;
3653 if (!parsed_valid_hugepagesz) {
3654 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3655 parsed_valid_hugepagesz = true;
3660 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3661 * yet, so this hugepages= parameter goes to the "default hstate".
3662 * Otherwise, it goes with the previously parsed hugepagesz or
3663 * default_hugepagesz.
3665 else if (!hugetlb_max_hstate)
3666 mhp = &default_hstate_max_huge_pages;
3668 mhp = &parsed_hstate->max_huge_pages;
3670 if (mhp == last_mhp) {
3671 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3675 if (sscanf(s, "%lu", mhp) <= 0)
3679 * Global state is always initialized later in hugetlb_init.
3680 * But we need to allocate gigantic hstates here early to still
3681 * use the bootmem allocator.
3683 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
3684 hugetlb_hstate_alloc_pages(parsed_hstate);
3690 __setup("hugepages=", hugepages_setup);
3693 * hugepagesz command line processing
3694 * A specific huge page size can only be specified once with hugepagesz.
3695 * hugepagesz is followed by hugepages on the command line. The global
3696 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3697 * hugepagesz argument was valid.
3699 static int __init hugepagesz_setup(char *s)
3704 parsed_valid_hugepagesz = false;
3705 size = (unsigned long)memparse(s, NULL);
3707 if (!arch_hugetlb_valid_size(size)) {
3708 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3712 h = size_to_hstate(size);
3715 * hstate for this size already exists. This is normally
3716 * an error, but is allowed if the existing hstate is the
3717 * default hstate. More specifically, it is only allowed if
3718 * the number of huge pages for the default hstate was not
3719 * previously specified.
3721 if (!parsed_default_hugepagesz || h != &default_hstate ||
3722 default_hstate.max_huge_pages) {
3723 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3728 * No need to call hugetlb_add_hstate() as hstate already
3729 * exists. But, do set parsed_hstate so that a following
3730 * hugepages= parameter will be applied to this hstate.
3733 parsed_valid_hugepagesz = true;
3737 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3738 parsed_valid_hugepagesz = true;
3741 __setup("hugepagesz=", hugepagesz_setup);
3744 * default_hugepagesz command line input
3745 * Only one instance of default_hugepagesz allowed on command line.
3747 static int __init default_hugepagesz_setup(char *s)
3751 parsed_valid_hugepagesz = false;
3752 if (parsed_default_hugepagesz) {
3753 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3757 size = (unsigned long)memparse(s, NULL);
3759 if (!arch_hugetlb_valid_size(size)) {
3760 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3764 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3765 parsed_valid_hugepagesz = true;
3766 parsed_default_hugepagesz = true;
3767 default_hstate_idx = hstate_index(size_to_hstate(size));
3770 * The number of default huge pages (for this size) could have been
3771 * specified as the first hugetlb parameter: hugepages=X. If so,
3772 * then default_hstate_max_huge_pages is set. If the default huge
3773 * page size is gigantic (>= MAX_ORDER), then the pages must be
3774 * allocated here from bootmem allocator.
3776 if (default_hstate_max_huge_pages) {
3777 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3778 if (hstate_is_gigantic(&default_hstate))
3779 hugetlb_hstate_alloc_pages(&default_hstate);
3780 default_hstate_max_huge_pages = 0;
3785 __setup("default_hugepagesz=", default_hugepagesz_setup);
3787 static unsigned int allowed_mems_nr(struct hstate *h)
3790 unsigned int nr = 0;
3791 nodemask_t *mpol_allowed;
3792 unsigned int *array = h->free_huge_pages_node;
3793 gfp_t gfp_mask = htlb_alloc_mask(h);
3795 mpol_allowed = policy_nodemask_current(gfp_mask);
3797 for_each_node_mask(node, cpuset_current_mems_allowed) {
3798 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3805 #ifdef CONFIG_SYSCTL
3806 static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3807 void *buffer, size_t *length,
3808 loff_t *ppos, unsigned long *out)
3810 struct ctl_table dup_table;
3813 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3814 * can duplicate the @table and alter the duplicate of it.
3817 dup_table.data = out;
3819 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3822 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3823 struct ctl_table *table, int write,
3824 void *buffer, size_t *length, loff_t *ppos)
3826 struct hstate *h = &default_hstate;
3827 unsigned long tmp = h->max_huge_pages;
3830 if (!hugepages_supported())
3833 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3839 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3840 NUMA_NO_NODE, tmp, *length);
3845 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3846 void *buffer, size_t *length, loff_t *ppos)
3849 return hugetlb_sysctl_handler_common(false, table, write,
3850 buffer, length, ppos);
3854 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3855 void *buffer, size_t *length, loff_t *ppos)
3857 return hugetlb_sysctl_handler_common(true, table, write,
3858 buffer, length, ppos);
3860 #endif /* CONFIG_NUMA */
3862 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3863 void *buffer, size_t *length, loff_t *ppos)
3865 struct hstate *h = &default_hstate;
3869 if (!hugepages_supported())
3872 tmp = h->nr_overcommit_huge_pages;
3874 if (write && hstate_is_gigantic(h))
3877 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3883 spin_lock_irq(&hugetlb_lock);
3884 h->nr_overcommit_huge_pages = tmp;
3885 spin_unlock_irq(&hugetlb_lock);
3891 #endif /* CONFIG_SYSCTL */
3893 void hugetlb_report_meminfo(struct seq_file *m)
3896 unsigned long total = 0;
3898 if (!hugepages_supported())
3901 for_each_hstate(h) {
3902 unsigned long count = h->nr_huge_pages;
3904 total += huge_page_size(h) * count;
3906 if (h == &default_hstate)
3908 "HugePages_Total: %5lu\n"
3909 "HugePages_Free: %5lu\n"
3910 "HugePages_Rsvd: %5lu\n"
3911 "HugePages_Surp: %5lu\n"
3912 "Hugepagesize: %8lu kB\n",
3916 h->surplus_huge_pages,
3917 huge_page_size(h) / SZ_1K);
3920 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3923 int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3925 struct hstate *h = &default_hstate;
3927 if (!hugepages_supported())
3930 return sysfs_emit_at(buf, len,
3931 "Node %d HugePages_Total: %5u\n"
3932 "Node %d HugePages_Free: %5u\n"
3933 "Node %d HugePages_Surp: %5u\n",
3934 nid, h->nr_huge_pages_node[nid],
3935 nid, h->free_huge_pages_node[nid],
3936 nid, h->surplus_huge_pages_node[nid]);
3939 void hugetlb_show_meminfo(void)
3944 if (!hugepages_supported())
3947 for_each_node_state(nid, N_MEMORY)
3949 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3951 h->nr_huge_pages_node[nid],
3952 h->free_huge_pages_node[nid],
3953 h->surplus_huge_pages_node[nid],
3954 huge_page_size(h) / SZ_1K);
3957 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3959 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3960 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3963 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3964 unsigned long hugetlb_total_pages(void)
3967 unsigned long nr_total_pages = 0;
3970 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3971 return nr_total_pages;
3974 static int hugetlb_acct_memory(struct hstate *h, long delta)
3981 spin_lock_irq(&hugetlb_lock);
3983 * When cpuset is configured, it breaks the strict hugetlb page
3984 * reservation as the accounting is done on a global variable. Such
3985 * reservation is completely rubbish in the presence of cpuset because
3986 * the reservation is not checked against page availability for the
3987 * current cpuset. Application can still potentially OOM'ed by kernel
3988 * with lack of free htlb page in cpuset that the task is in.
3989 * Attempt to enforce strict accounting with cpuset is almost
3990 * impossible (or too ugly) because cpuset is too fluid that
3991 * task or memory node can be dynamically moved between cpusets.
3993 * The change of semantics for shared hugetlb mapping with cpuset is
3994 * undesirable. However, in order to preserve some of the semantics,
3995 * we fall back to check against current free page availability as
3996 * a best attempt and hopefully to minimize the impact of changing
3997 * semantics that cpuset has.
3999 * Apart from cpuset, we also have memory policy mechanism that
4000 * also determines from which node the kernel will allocate memory
4001 * in a NUMA system. So similar to cpuset, we also should consider
4002 * the memory policy of the current task. Similar to the description
4006 if (gather_surplus_pages(h, delta) < 0)
4009 if (delta > allowed_mems_nr(h)) {
4010 return_unused_surplus_pages(h, delta);
4017 return_unused_surplus_pages(h, (unsigned long) -delta);
4020 spin_unlock_irq(&hugetlb_lock);
4024 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
4026 struct resv_map *resv = vma_resv_map(vma);
4029 * This new VMA should share its siblings reservation map if present.
4030 * The VMA will only ever have a valid reservation map pointer where
4031 * it is being copied for another still existing VMA. As that VMA
4032 * has a reference to the reservation map it cannot disappear until
4033 * after this open call completes. It is therefore safe to take a
4034 * new reference here without additional locking.
4036 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4037 kref_get(&resv->refs);
4040 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
4042 struct hstate *h = hstate_vma(vma);
4043 struct resv_map *resv = vma_resv_map(vma);
4044 struct hugepage_subpool *spool = subpool_vma(vma);
4045 unsigned long reserve, start, end;
4048 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4051 start = vma_hugecache_offset(h, vma, vma->vm_start);
4052 end = vma_hugecache_offset(h, vma, vma->vm_end);
4054 reserve = (end - start) - region_count(resv, start, end);
4055 hugetlb_cgroup_uncharge_counter(resv, start, end);
4058 * Decrement reserve counts. The global reserve count may be
4059 * adjusted if the subpool has a minimum size.
4061 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
4062 hugetlb_acct_memory(h, -gbl_reserve);
4065 kref_put(&resv->refs, resv_map_release);
4068 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
4070 if (addr & ~(huge_page_mask(hstate_vma(vma))))
4075 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
4077 return huge_page_size(hstate_vma(vma));
4081 * We cannot handle pagefaults against hugetlb pages at all. They cause
4082 * handle_mm_fault() to try to instantiate regular-sized pages in the
4083 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
4086 static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
4093 * When a new function is introduced to vm_operations_struct and added
4094 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
4095 * This is because under System V memory model, mappings created via
4096 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
4097 * their original vm_ops are overwritten with shm_vm_ops.
4099 const struct vm_operations_struct hugetlb_vm_ops = {
4100 .fault = hugetlb_vm_op_fault,
4101 .open = hugetlb_vm_op_open,
4102 .close = hugetlb_vm_op_close,
4103 .may_split = hugetlb_vm_op_split,
4104 .pagesize = hugetlb_vm_op_pagesize,
4107 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
4111 unsigned int shift = huge_page_shift(hstate_vma(vma));
4114 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
4115 vma->vm_page_prot)));
4117 entry = huge_pte_wrprotect(mk_huge_pte(page,
4118 vma->vm_page_prot));
4120 entry = pte_mkyoung(entry);
4121 entry = pte_mkhuge(entry);
4122 entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
4127 static void set_huge_ptep_writable(struct vm_area_struct *vma,
4128 unsigned long address, pte_t *ptep)
4132 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
4133 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
4134 update_mmu_cache(vma, address, ptep);
4137 bool is_hugetlb_entry_migration(pte_t pte)
4141 if (huge_pte_none(pte) || pte_present(pte))
4143 swp = pte_to_swp_entry(pte);
4144 if (is_migration_entry(swp))
4150 static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
4154 if (huge_pte_none(pte) || pte_present(pte))
4156 swp = pte_to_swp_entry(pte);
4157 if (is_hwpoison_entry(swp))
4164 hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
4165 struct page *new_page)
4167 __SetPageUptodate(new_page);
4168 set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1));
4169 hugepage_add_new_anon_rmap(new_page, vma, addr);
4170 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
4171 ClearHPageRestoreReserve(new_page);
4172 SetHPageMigratable(new_page);
4175 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
4176 struct vm_area_struct *vma)
4178 pte_t *src_pte, *dst_pte, entry, dst_entry;
4179 struct page *ptepage;
4181 bool cow = is_cow_mapping(vma->vm_flags);
4182 struct hstate *h = hstate_vma(vma);
4183 unsigned long sz = huge_page_size(h);
4184 unsigned long npages = pages_per_huge_page(h);
4185 struct address_space *mapping = vma->vm_file->f_mapping;
4186 struct mmu_notifier_range range;
4190 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
4193 mmu_notifier_invalidate_range_start(&range);
4196 * For shared mappings i_mmap_rwsem must be held to call
4197 * huge_pte_alloc, otherwise the returned ptep could go
4198 * away if part of a shared pmd and another thread calls
4201 i_mmap_lock_read(mapping);
4204 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
4205 spinlock_t *src_ptl, *dst_ptl;
4206 src_pte = huge_pte_offset(src, addr, sz);
4209 dst_pte = huge_pte_alloc(dst, vma, addr, sz);
4216 * If the pagetables are shared don't copy or take references.
4217 * dst_pte == src_pte is the common case of src/dest sharing.
4219 * However, src could have 'unshared' and dst shares with
4220 * another vma. If dst_pte !none, this implies sharing.
4221 * Check here before taking page table lock, and once again
4222 * after taking the lock below.
4224 dst_entry = huge_ptep_get(dst_pte);
4225 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
4228 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4229 src_ptl = huge_pte_lockptr(h, src, src_pte);
4230 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4231 entry = huge_ptep_get(src_pte);
4232 dst_entry = huge_ptep_get(dst_pte);
4234 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
4236 * Skip if src entry none. Also, skip in the
4237 * unlikely case dst entry !none as this implies
4238 * sharing with another vma.
4241 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
4242 is_hugetlb_entry_hwpoisoned(entry))) {
4243 swp_entry_t swp_entry = pte_to_swp_entry(entry);
4245 if (is_writable_migration_entry(swp_entry) && cow) {
4247 * COW mappings require pages in both
4248 * parent and child to be set to read.
4250 swp_entry = make_readable_migration_entry(
4251 swp_offset(swp_entry));
4252 entry = swp_entry_to_pte(swp_entry);
4253 set_huge_swap_pte_at(src, addr, src_pte,
4256 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
4258 entry = huge_ptep_get(src_pte);
4259 ptepage = pte_page(entry);
4263 * This is a rare case where we see pinned hugetlb
4264 * pages while they're prone to COW. We need to do the
4265 * COW earlier during fork.
4267 * When pre-allocating the page or copying data, we
4268 * need to be without the pgtable locks since we could
4269 * sleep during the process.
4271 if (unlikely(page_needs_cow_for_dma(vma, ptepage))) {
4272 pte_t src_pte_old = entry;
4275 spin_unlock(src_ptl);
4276 spin_unlock(dst_ptl);
4277 /* Do not use reserve as it's private owned */
4278 new = alloc_huge_page(vma, addr, 1);
4284 copy_user_huge_page(new, ptepage, addr, vma,
4288 /* Install the new huge page if src pte stable */
4289 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4290 src_ptl = huge_pte_lockptr(h, src, src_pte);
4291 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4292 entry = huge_ptep_get(src_pte);
4293 if (!pte_same(src_pte_old, entry)) {
4294 restore_reserve_on_error(h, vma, addr,
4297 /* dst_entry won't change as in child */
4300 hugetlb_install_page(vma, dst_pte, addr, new);
4301 spin_unlock(src_ptl);
4302 spin_unlock(dst_ptl);
4308 * No need to notify as we are downgrading page
4309 * table protection not changing it to point
4312 * See Documentation/vm/mmu_notifier.rst
4314 huge_ptep_set_wrprotect(src, addr, src_pte);
4315 entry = huge_pte_wrprotect(entry);
4318 page_dup_rmap(ptepage, true);
4319 set_huge_pte_at(dst, addr, dst_pte, entry);
4320 hugetlb_count_add(npages, dst);
4322 spin_unlock(src_ptl);
4323 spin_unlock(dst_ptl);
4327 mmu_notifier_invalidate_range_end(&range);
4329 i_mmap_unlock_read(mapping);
4334 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
4335 unsigned long start, unsigned long end,
4336 struct page *ref_page)
4338 struct mm_struct *mm = vma->vm_mm;
4339 unsigned long address;
4344 struct hstate *h = hstate_vma(vma);
4345 unsigned long sz = huge_page_size(h);
4346 struct mmu_notifier_range range;
4348 WARN_ON(!is_vm_hugetlb_page(vma));
4349 BUG_ON(start & ~huge_page_mask(h));
4350 BUG_ON(end & ~huge_page_mask(h));
4353 * This is a hugetlb vma, all the pte entries should point
4356 tlb_change_page_size(tlb, sz);
4357 tlb_start_vma(tlb, vma);
4360 * If sharing possible, alert mmu notifiers of worst case.
4362 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
4364 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4365 mmu_notifier_invalidate_range_start(&range);
4367 for (; address < end; address += sz) {
4368 ptep = huge_pte_offset(mm, address, sz);
4372 ptl = huge_pte_lock(h, mm, ptep);
4373 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
4376 * We just unmapped a page of PMDs by clearing a PUD.
4377 * The caller's TLB flush range should cover this area.
4382 pte = huge_ptep_get(ptep);
4383 if (huge_pte_none(pte)) {
4389 * Migrating hugepage or HWPoisoned hugepage is already
4390 * unmapped and its refcount is dropped, so just clear pte here.
4392 if (unlikely(!pte_present(pte))) {
4393 huge_pte_clear(mm, address, ptep, sz);
4398 page = pte_page(pte);
4400 * If a reference page is supplied, it is because a specific
4401 * page is being unmapped, not a range. Ensure the page we
4402 * are about to unmap is the actual page of interest.
4405 if (page != ref_page) {
4410 * Mark the VMA as having unmapped its page so that
4411 * future faults in this VMA will fail rather than
4412 * looking like data was lost
4414 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4417 pte = huge_ptep_get_and_clear(mm, address, ptep);
4418 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4419 if (huge_pte_dirty(pte))
4420 set_page_dirty(page);
4422 hugetlb_count_sub(pages_per_huge_page(h), mm);
4423 page_remove_rmap(page, true);
4426 tlb_remove_page_size(tlb, page, huge_page_size(h));
4428 * Bail out after unmapping reference page if supplied
4433 mmu_notifier_invalidate_range_end(&range);
4434 tlb_end_vma(tlb, vma);
4437 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4438 struct vm_area_struct *vma, unsigned long start,
4439 unsigned long end, struct page *ref_page)
4441 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4444 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4445 * test will fail on a vma being torn down, and not grab a page table
4446 * on its way out. We're lucky that the flag has such an appropriate
4447 * name, and can in fact be safely cleared here. We could clear it
4448 * before the __unmap_hugepage_range above, but all that's necessary
4449 * is to clear it before releasing the i_mmap_rwsem. This works
4450 * because in the context this is called, the VMA is about to be
4451 * destroyed and the i_mmap_rwsem is held.
4453 vma->vm_flags &= ~VM_MAYSHARE;
4456 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4457 unsigned long end, struct page *ref_page)
4459 struct mmu_gather tlb;
4461 tlb_gather_mmu(&tlb, vma->vm_mm);
4462 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4463 tlb_finish_mmu(&tlb);
4467 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4468 * mapping it owns the reserve page for. The intention is to unmap the page
4469 * from other VMAs and let the children be SIGKILLed if they are faulting the
4472 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4473 struct page *page, unsigned long address)
4475 struct hstate *h = hstate_vma(vma);
4476 struct vm_area_struct *iter_vma;
4477 struct address_space *mapping;
4481 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4482 * from page cache lookup which is in HPAGE_SIZE units.
4484 address = address & huge_page_mask(h);
4485 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4487 mapping = vma->vm_file->f_mapping;
4490 * Take the mapping lock for the duration of the table walk. As
4491 * this mapping should be shared between all the VMAs,
4492 * __unmap_hugepage_range() is called as the lock is already held
4494 i_mmap_lock_write(mapping);
4495 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4496 /* Do not unmap the current VMA */
4497 if (iter_vma == vma)
4501 * Shared VMAs have their own reserves and do not affect
4502 * MAP_PRIVATE accounting but it is possible that a shared
4503 * VMA is using the same page so check and skip such VMAs.
4505 if (iter_vma->vm_flags & VM_MAYSHARE)
4509 * Unmap the page from other VMAs without their own reserves.
4510 * They get marked to be SIGKILLed if they fault in these
4511 * areas. This is because a future no-page fault on this VMA
4512 * could insert a zeroed page instead of the data existing
4513 * from the time of fork. This would look like data corruption
4515 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4516 unmap_hugepage_range(iter_vma, address,
4517 address + huge_page_size(h), page);
4519 i_mmap_unlock_write(mapping);
4523 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4524 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4525 * cannot race with other handlers or page migration.
4526 * Keep the pte_same checks anyway to make transition from the mutex easier.
4528 static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4529 unsigned long address, pte_t *ptep,
4530 struct page *pagecache_page, spinlock_t *ptl)
4533 struct hstate *h = hstate_vma(vma);
4534 struct page *old_page, *new_page;
4535 int outside_reserve = 0;
4537 unsigned long haddr = address & huge_page_mask(h);
4538 struct mmu_notifier_range range;
4540 pte = huge_ptep_get(ptep);
4541 old_page = pte_page(pte);
4544 /* If no-one else is actually using this page, avoid the copy
4545 * and just make the page writable */
4546 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4547 page_move_anon_rmap(old_page, vma);
4548 set_huge_ptep_writable(vma, haddr, ptep);
4553 * If the process that created a MAP_PRIVATE mapping is about to
4554 * perform a COW due to a shared page count, attempt to satisfy
4555 * the allocation without using the existing reserves. The pagecache
4556 * page is used to determine if the reserve at this address was
4557 * consumed or not. If reserves were used, a partial faulted mapping
4558 * at the time of fork() could consume its reserves on COW instead
4559 * of the full address range.
4561 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4562 old_page != pagecache_page)
4563 outside_reserve = 1;
4568 * Drop page table lock as buddy allocator may be called. It will
4569 * be acquired again before returning to the caller, as expected.
4572 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4574 if (IS_ERR(new_page)) {
4576 * If a process owning a MAP_PRIVATE mapping fails to COW,
4577 * it is due to references held by a child and an insufficient
4578 * huge page pool. To guarantee the original mappers
4579 * reliability, unmap the page from child processes. The child
4580 * may get SIGKILLed if it later faults.
4582 if (outside_reserve) {
4583 struct address_space *mapping = vma->vm_file->f_mapping;
4588 BUG_ON(huge_pte_none(pte));
4590 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4591 * unmapping. unmapping needs to hold i_mmap_rwsem
4592 * in write mode. Dropping i_mmap_rwsem in read mode
4593 * here is OK as COW mappings do not interact with
4596 * Reacquire both after unmap operation.
4598 idx = vma_hugecache_offset(h, vma, haddr);
4599 hash = hugetlb_fault_mutex_hash(mapping, idx);
4600 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4601 i_mmap_unlock_read(mapping);
4603 unmap_ref_private(mm, vma, old_page, haddr);
4605 i_mmap_lock_read(mapping);
4606 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4608 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4610 pte_same(huge_ptep_get(ptep), pte)))
4611 goto retry_avoidcopy;
4613 * race occurs while re-acquiring page table
4614 * lock, and our job is done.
4619 ret = vmf_error(PTR_ERR(new_page));
4620 goto out_release_old;
4624 * When the original hugepage is shared one, it does not have
4625 * anon_vma prepared.
4627 if (unlikely(anon_vma_prepare(vma))) {
4629 goto out_release_all;
4632 copy_user_huge_page(new_page, old_page, address, vma,
4633 pages_per_huge_page(h));
4634 __SetPageUptodate(new_page);
4636 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4637 haddr + huge_page_size(h));
4638 mmu_notifier_invalidate_range_start(&range);
4641 * Retake the page table lock to check for racing updates
4642 * before the page tables are altered
4645 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4646 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4647 ClearHPageRestoreReserve(new_page);
4650 huge_ptep_clear_flush(vma, haddr, ptep);
4651 mmu_notifier_invalidate_range(mm, range.start, range.end);
4652 set_huge_pte_at(mm, haddr, ptep,
4653 make_huge_pte(vma, new_page, 1));
4654 page_remove_rmap(old_page, true);
4655 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4656 SetHPageMigratable(new_page);
4657 /* Make the old page be freed below */
4658 new_page = old_page;
4661 mmu_notifier_invalidate_range_end(&range);
4663 restore_reserve_on_error(h, vma, haddr, new_page);
4668 spin_lock(ptl); /* Caller expects lock to be held */
4672 /* Return the pagecache page at a given address within a VMA */
4673 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4674 struct vm_area_struct *vma, unsigned long address)
4676 struct address_space *mapping;
4679 mapping = vma->vm_file->f_mapping;
4680 idx = vma_hugecache_offset(h, vma, address);
4682 return find_lock_page(mapping, idx);
4686 * Return whether there is a pagecache page to back given address within VMA.
4687 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4689 static bool hugetlbfs_pagecache_present(struct hstate *h,
4690 struct vm_area_struct *vma, unsigned long address)
4692 struct address_space *mapping;
4696 mapping = vma->vm_file->f_mapping;
4697 idx = vma_hugecache_offset(h, vma, address);
4699 page = find_get_page(mapping, idx);
4702 return page != NULL;
4705 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4708 struct inode *inode = mapping->host;
4709 struct hstate *h = hstate_inode(inode);
4710 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4714 ClearHPageRestoreReserve(page);
4717 * set page dirty so that it will not be removed from cache/file
4718 * by non-hugetlbfs specific code paths.
4720 set_page_dirty(page);
4722 spin_lock(&inode->i_lock);
4723 inode->i_blocks += blocks_per_huge_page(h);
4724 spin_unlock(&inode->i_lock);
4728 static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
4729 struct address_space *mapping,
4732 unsigned long haddr,
4733 unsigned long reason)
4737 struct vm_fault vmf = {
4743 * Hard to debug if it ends up being
4744 * used by a callee that assumes
4745 * something about the other
4746 * uninitialized fields... same as in
4752 * hugetlb_fault_mutex and i_mmap_rwsem must be
4753 * dropped before handling userfault. Reacquire
4754 * after handling fault to make calling code simpler.
4756 hash = hugetlb_fault_mutex_hash(mapping, idx);
4757 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4758 i_mmap_unlock_read(mapping);
4759 ret = handle_userfault(&vmf, reason);
4760 i_mmap_lock_read(mapping);
4761 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4766 static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4767 struct vm_area_struct *vma,
4768 struct address_space *mapping, pgoff_t idx,
4769 unsigned long address, pte_t *ptep, unsigned int flags)
4771 struct hstate *h = hstate_vma(vma);
4772 vm_fault_t ret = VM_FAULT_SIGBUS;
4778 unsigned long haddr = address & huge_page_mask(h);
4779 bool new_page = false;
4782 * Currently, we are forced to kill the process in the event the
4783 * original mapper has unmapped pages from the child due to a failed
4784 * COW. Warn that such a situation has occurred as it may not be obvious
4786 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4787 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4793 * We can not race with truncation due to holding i_mmap_rwsem.
4794 * i_size is modified when holding i_mmap_rwsem, so check here
4795 * once for faults beyond end of file.
4797 size = i_size_read(mapping->host) >> huge_page_shift(h);
4802 page = find_lock_page(mapping, idx);
4804 /* Check for page in userfault range */
4805 if (userfaultfd_missing(vma)) {
4806 ret = hugetlb_handle_userfault(vma, mapping, idx,
4812 page = alloc_huge_page(vma, haddr, 0);
4815 * Returning error will result in faulting task being
4816 * sent SIGBUS. The hugetlb fault mutex prevents two
4817 * tasks from racing to fault in the same page which
4818 * could result in false unable to allocate errors.
4819 * Page migration does not take the fault mutex, but
4820 * does a clear then write of pte's under page table
4821 * lock. Page fault code could race with migration,
4822 * notice the clear pte and try to allocate a page
4823 * here. Before returning error, get ptl and make
4824 * sure there really is no pte entry.
4826 ptl = huge_pte_lock(h, mm, ptep);
4828 if (huge_pte_none(huge_ptep_get(ptep)))
4829 ret = vmf_error(PTR_ERR(page));
4833 clear_huge_page(page, address, pages_per_huge_page(h));
4834 __SetPageUptodate(page);
4837 if (vma->vm_flags & VM_MAYSHARE) {
4838 int err = huge_add_to_page_cache(page, mapping, idx);
4847 if (unlikely(anon_vma_prepare(vma))) {
4849 goto backout_unlocked;
4855 * If memory error occurs between mmap() and fault, some process
4856 * don't have hwpoisoned swap entry for errored virtual address.
4857 * So we need to block hugepage fault by PG_hwpoison bit check.
4859 if (unlikely(PageHWPoison(page))) {
4860 ret = VM_FAULT_HWPOISON_LARGE |
4861 VM_FAULT_SET_HINDEX(hstate_index(h));
4862 goto backout_unlocked;
4865 /* Check for page in userfault range. */
4866 if (userfaultfd_minor(vma)) {
4869 ret = hugetlb_handle_userfault(vma, mapping, idx,
4877 * If we are going to COW a private mapping later, we examine the
4878 * pending reservations for this page now. This will ensure that
4879 * any allocations necessary to record that reservation occur outside
4882 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4883 if (vma_needs_reservation(h, vma, haddr) < 0) {
4885 goto backout_unlocked;
4887 /* Just decrements count, does not deallocate */
4888 vma_end_reservation(h, vma, haddr);
4891 ptl = huge_pte_lock(h, mm, ptep);
4893 if (!huge_pte_none(huge_ptep_get(ptep)))
4897 ClearHPageRestoreReserve(page);
4898 hugepage_add_new_anon_rmap(page, vma, haddr);
4900 page_dup_rmap(page, true);
4901 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4902 && (vma->vm_flags & VM_SHARED)));
4903 set_huge_pte_at(mm, haddr, ptep, new_pte);
4905 hugetlb_count_add(pages_per_huge_page(h), mm);
4906 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4907 /* Optimization, do the COW without a second fault */
4908 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4914 * Only set HPageMigratable in newly allocated pages. Existing pages
4915 * found in the pagecache may not have HPageMigratableset if they have
4916 * been isolated for migration.
4919 SetHPageMigratable(page);
4929 restore_reserve_on_error(h, vma, haddr, page);
4935 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4937 unsigned long key[2];
4940 key[0] = (unsigned long) mapping;
4943 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4945 return hash & (num_fault_mutexes - 1);
4949 * For uniprocessor systems we always use a single mutex, so just
4950 * return 0 and avoid the hashing overhead.
4952 u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4958 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4959 unsigned long address, unsigned int flags)
4966 struct page *page = NULL;
4967 struct page *pagecache_page = NULL;
4968 struct hstate *h = hstate_vma(vma);
4969 struct address_space *mapping;
4970 int need_wait_lock = 0;
4971 unsigned long haddr = address & huge_page_mask(h);
4973 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4976 * Since we hold no locks, ptep could be stale. That is
4977 * OK as we are only making decisions based on content and
4978 * not actually modifying content here.
4980 entry = huge_ptep_get(ptep);
4981 if (unlikely(is_hugetlb_entry_migration(entry))) {
4982 migration_entry_wait_huge(vma, mm, ptep);
4984 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4985 return VM_FAULT_HWPOISON_LARGE |
4986 VM_FAULT_SET_HINDEX(hstate_index(h));
4990 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4991 * until finished with ptep. This serves two purposes:
4992 * 1) It prevents huge_pmd_unshare from being called elsewhere
4993 * and making the ptep no longer valid.
4994 * 2) It synchronizes us with i_size modifications during truncation.
4996 * ptep could have already be assigned via huge_pte_offset. That
4997 * is OK, as huge_pte_alloc will return the same value unless
4998 * something has changed.
5000 mapping = vma->vm_file->f_mapping;
5001 i_mmap_lock_read(mapping);
5002 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
5004 i_mmap_unlock_read(mapping);
5005 return VM_FAULT_OOM;
5009 * Serialize hugepage allocation and instantiation, so that we don't
5010 * get spurious allocation failures if two CPUs race to instantiate
5011 * the same page in the page cache.
5013 idx = vma_hugecache_offset(h, vma, haddr);
5014 hash = hugetlb_fault_mutex_hash(mapping, idx);
5015 mutex_lock(&hugetlb_fault_mutex_table[hash]);
5017 entry = huge_ptep_get(ptep);
5018 if (huge_pte_none(entry)) {
5019 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
5026 * entry could be a migration/hwpoison entry at this point, so this
5027 * check prevents the kernel from going below assuming that we have
5028 * an active hugepage in pagecache. This goto expects the 2nd page
5029 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
5030 * properly handle it.
5032 if (!pte_present(entry))
5036 * If we are going to COW the mapping later, we examine the pending
5037 * reservations for this page now. This will ensure that any
5038 * allocations necessary to record that reservation occur outside the
5039 * spinlock. For private mappings, we also lookup the pagecache
5040 * page now as it is used to determine if a reservation has been
5043 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
5044 if (vma_needs_reservation(h, vma, haddr) < 0) {
5048 /* Just decrements count, does not deallocate */
5049 vma_end_reservation(h, vma, haddr);
5051 if (!(vma->vm_flags & VM_MAYSHARE))
5052 pagecache_page = hugetlbfs_pagecache_page(h,
5056 ptl = huge_pte_lock(h, mm, ptep);
5058 /* Check for a racing update before calling hugetlb_cow */
5059 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
5063 * hugetlb_cow() requires page locks of pte_page(entry) and
5064 * pagecache_page, so here we need take the former one
5065 * when page != pagecache_page or !pagecache_page.
5067 page = pte_page(entry);
5068 if (page != pagecache_page)
5069 if (!trylock_page(page)) {
5076 if (flags & FAULT_FLAG_WRITE) {
5077 if (!huge_pte_write(entry)) {
5078 ret = hugetlb_cow(mm, vma, address, ptep,
5079 pagecache_page, ptl);
5082 entry = huge_pte_mkdirty(entry);
5084 entry = pte_mkyoung(entry);
5085 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
5086 flags & FAULT_FLAG_WRITE))
5087 update_mmu_cache(vma, haddr, ptep);
5089 if (page != pagecache_page)
5095 if (pagecache_page) {
5096 unlock_page(pagecache_page);
5097 put_page(pagecache_page);
5100 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
5101 i_mmap_unlock_read(mapping);
5103 * Generally it's safe to hold refcount during waiting page lock. But
5104 * here we just wait to defer the next page fault to avoid busy loop and
5105 * the page is not used after unlocked before returning from the current
5106 * page fault. So we are safe from accessing freed page, even if we wait
5107 * here without taking refcount.
5110 wait_on_page_locked(page);
5114 #ifdef CONFIG_USERFAULTFD
5116 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
5117 * modifications for huge pages.
5119 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
5121 struct vm_area_struct *dst_vma,
5122 unsigned long dst_addr,
5123 unsigned long src_addr,
5124 enum mcopy_atomic_mode mode,
5125 struct page **pagep)
5127 bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
5128 struct hstate *h = hstate_vma(dst_vma);
5129 struct address_space *mapping = dst_vma->vm_file->f_mapping;
5130 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
5132 int vm_shared = dst_vma->vm_flags & VM_SHARED;
5141 page = find_lock_page(mapping, idx);
5144 } else if (!*pagep) {
5145 /* If a page already exists, then it's UFFDIO_COPY for
5146 * a non-missing case. Return -EEXIST.
5149 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
5154 page = alloc_huge_page(dst_vma, dst_addr, 0);
5160 ret = copy_huge_page_from_user(page,
5161 (const void __user *) src_addr,
5162 pages_per_huge_page(h), false);
5164 /* fallback to copy_from_user outside mmap_lock */
5165 if (unlikely(ret)) {
5167 /* Free the allocated page which may have
5168 * consumed a reservation.
5170 restore_reserve_on_error(h, dst_vma, dst_addr, page);
5173 /* Allocate a temporary page to hold the copied
5176 page = alloc_huge_page_vma(h, dst_vma, dst_addr);
5182 /* Set the outparam pagep and return to the caller to
5183 * copy the contents outside the lock. Don't free the
5190 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
5197 page = alloc_huge_page(dst_vma, dst_addr, 0);
5203 copy_huge_page(page, *pagep);
5209 * The memory barrier inside __SetPageUptodate makes sure that
5210 * preceding stores to the page contents become visible before
5211 * the set_pte_at() write.
5213 __SetPageUptodate(page);
5215 /* Add shared, newly allocated pages to the page cache. */
5216 if (vm_shared && !is_continue) {
5217 size = i_size_read(mapping->host) >> huge_page_shift(h);
5220 goto out_release_nounlock;
5223 * Serialization between remove_inode_hugepages() and
5224 * huge_add_to_page_cache() below happens through the
5225 * hugetlb_fault_mutex_table that here must be hold by
5228 ret = huge_add_to_page_cache(page, mapping, idx);
5230 goto out_release_nounlock;
5233 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
5237 * Recheck the i_size after holding PT lock to make sure not
5238 * to leave any page mapped (as page_mapped()) beyond the end
5239 * of the i_size (remove_inode_hugepages() is strict about
5240 * enforcing that). If we bail out here, we'll also leave a
5241 * page in the radix tree in the vm_shared case beyond the end
5242 * of the i_size, but remove_inode_hugepages() will take care
5243 * of it as soon as we drop the hugetlb_fault_mutex_table.
5245 size = i_size_read(mapping->host) >> huge_page_shift(h);
5248 goto out_release_unlock;
5251 if (!huge_pte_none(huge_ptep_get(dst_pte)))
5252 goto out_release_unlock;
5255 page_dup_rmap(page, true);
5257 ClearHPageRestoreReserve(page);
5258 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
5261 /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
5262 if (is_continue && !vm_shared)
5265 writable = dst_vma->vm_flags & VM_WRITE;
5267 _dst_pte = make_huge_pte(dst_vma, page, writable);
5269 _dst_pte = huge_pte_mkdirty(_dst_pte);
5270 _dst_pte = pte_mkyoung(_dst_pte);
5272 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
5274 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
5275 dst_vma->vm_flags & VM_WRITE);
5276 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
5278 /* No need to invalidate - it was non-present before */
5279 update_mmu_cache(dst_vma, dst_addr, dst_pte);
5283 SetHPageMigratable(page);
5284 if (vm_shared || is_continue)
5291 if (vm_shared || is_continue)
5293 out_release_nounlock:
5294 restore_reserve_on_error(h, dst_vma, dst_addr, page);
5298 #endif /* CONFIG_USERFAULTFD */
5300 static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
5301 int refs, struct page **pages,
5302 struct vm_area_struct **vmas)
5306 for (nr = 0; nr < refs; nr++) {
5308 pages[nr] = mem_map_offset(page, nr);
5314 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
5315 struct page **pages, struct vm_area_struct **vmas,
5316 unsigned long *position, unsigned long *nr_pages,
5317 long i, unsigned int flags, int *locked)
5319 unsigned long pfn_offset;
5320 unsigned long vaddr = *position;
5321 unsigned long remainder = *nr_pages;
5322 struct hstate *h = hstate_vma(vma);
5323 int err = -EFAULT, refs;
5325 while (vaddr < vma->vm_end && remainder) {
5327 spinlock_t *ptl = NULL;
5332 * If we have a pending SIGKILL, don't keep faulting pages and
5333 * potentially allocating memory.
5335 if (fatal_signal_pending(current)) {
5341 * Some archs (sparc64, sh*) have multiple pte_ts to
5342 * each hugepage. We have to make sure we get the
5343 * first, for the page indexing below to work.
5345 * Note that page table lock is not held when pte is null.
5347 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
5350 ptl = huge_pte_lock(h, mm, pte);
5351 absent = !pte || huge_pte_none(huge_ptep_get(pte));
5354 * When coredumping, it suits get_dump_page if we just return
5355 * an error where there's an empty slot with no huge pagecache
5356 * to back it. This way, we avoid allocating a hugepage, and
5357 * the sparse dumpfile avoids allocating disk blocks, but its
5358 * huge holes still show up with zeroes where they need to be.
5360 if (absent && (flags & FOLL_DUMP) &&
5361 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
5369 * We need call hugetlb_fault for both hugepages under migration
5370 * (in which case hugetlb_fault waits for the migration,) and
5371 * hwpoisoned hugepages (in which case we need to prevent the
5372 * caller from accessing to them.) In order to do this, we use
5373 * here is_swap_pte instead of is_hugetlb_entry_migration and
5374 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
5375 * both cases, and because we can't follow correct pages
5376 * directly from any kind of swap entries.
5378 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
5379 ((flags & FOLL_WRITE) &&
5380 !huge_pte_write(huge_ptep_get(pte)))) {
5382 unsigned int fault_flags = 0;
5386 if (flags & FOLL_WRITE)
5387 fault_flags |= FAULT_FLAG_WRITE;
5389 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5390 FAULT_FLAG_KILLABLE;
5391 if (flags & FOLL_NOWAIT)
5392 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5393 FAULT_FLAG_RETRY_NOWAIT;
5394 if (flags & FOLL_TRIED) {
5396 * Note: FAULT_FLAG_ALLOW_RETRY and
5397 * FAULT_FLAG_TRIED can co-exist
5399 fault_flags |= FAULT_FLAG_TRIED;
5401 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
5402 if (ret & VM_FAULT_ERROR) {
5403 err = vm_fault_to_errno(ret, flags);
5407 if (ret & VM_FAULT_RETRY) {
5409 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
5413 * VM_FAULT_RETRY must not return an
5414 * error, it will return zero
5417 * No need to update "position" as the
5418 * caller will not check it after
5419 * *nr_pages is set to 0.
5426 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
5427 page = pte_page(huge_ptep_get(pte));
5430 * If subpage information not requested, update counters
5431 * and skip the same_page loop below.
5433 if (!pages && !vmas && !pfn_offset &&
5434 (vaddr + huge_page_size(h) < vma->vm_end) &&
5435 (remainder >= pages_per_huge_page(h))) {
5436 vaddr += huge_page_size(h);
5437 remainder -= pages_per_huge_page(h);
5438 i += pages_per_huge_page(h);
5443 refs = min3(pages_per_huge_page(h) - pfn_offset,
5444 (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
5447 record_subpages_vmas(mem_map_offset(page, pfn_offset),
5449 likely(pages) ? pages + i : NULL,
5450 vmas ? vmas + i : NULL);
5454 * try_grab_compound_head() should always succeed here,
5455 * because: a) we hold the ptl lock, and b) we've just
5456 * checked that the huge page is present in the page
5457 * tables. If the huge page is present, then the tail
5458 * pages must also be present. The ptl prevents the
5459 * head page and tail pages from being rearranged in
5460 * any way. So this page must be available at this
5461 * point, unless the page refcount overflowed:
5463 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
5473 vaddr += (refs << PAGE_SHIFT);
5479 *nr_pages = remainder;
5481 * setting position is actually required only if remainder is
5482 * not zero but it's faster not to add a "if (remainder)"
5490 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5491 unsigned long address, unsigned long end, pgprot_t newprot)
5493 struct mm_struct *mm = vma->vm_mm;
5494 unsigned long start = address;
5497 struct hstate *h = hstate_vma(vma);
5498 unsigned long pages = 0;
5499 bool shared_pmd = false;
5500 struct mmu_notifier_range range;
5503 * In the case of shared PMDs, the area to flush could be beyond
5504 * start/end. Set range.start/range.end to cover the maximum possible
5505 * range if PMD sharing is possible.
5507 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5508 0, vma, mm, start, end);
5509 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5511 BUG_ON(address >= end);
5512 flush_cache_range(vma, range.start, range.end);
5514 mmu_notifier_invalidate_range_start(&range);
5515 i_mmap_lock_write(vma->vm_file->f_mapping);
5516 for (; address < end; address += huge_page_size(h)) {
5518 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5521 ptl = huge_pte_lock(h, mm, ptep);
5522 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5528 pte = huge_ptep_get(ptep);
5529 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5533 if (unlikely(is_hugetlb_entry_migration(pte))) {
5534 swp_entry_t entry = pte_to_swp_entry(pte);
5536 if (is_writable_migration_entry(entry)) {
5539 entry = make_readable_migration_entry(
5541 newpte = swp_entry_to_pte(entry);
5542 set_huge_swap_pte_at(mm, address, ptep,
5543 newpte, huge_page_size(h));
5549 if (!huge_pte_none(pte)) {
5551 unsigned int shift = huge_page_shift(hstate_vma(vma));
5553 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5554 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5555 pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
5556 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5562 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5563 * may have cleared our pud entry and done put_page on the page table:
5564 * once we release i_mmap_rwsem, another task can do the final put_page
5565 * and that page table be reused and filled with junk. If we actually
5566 * did unshare a page of pmds, flush the range corresponding to the pud.
5569 flush_hugetlb_tlb_range(vma, range.start, range.end);
5571 flush_hugetlb_tlb_range(vma, start, end);
5573 * No need to call mmu_notifier_invalidate_range() we are downgrading
5574 * page table protection not changing it to point to a new page.
5576 * See Documentation/vm/mmu_notifier.rst
5578 i_mmap_unlock_write(vma->vm_file->f_mapping);
5579 mmu_notifier_invalidate_range_end(&range);
5581 return pages << h->order;
5584 /* Return true if reservation was successful, false otherwise. */
5585 bool hugetlb_reserve_pages(struct inode *inode,
5587 struct vm_area_struct *vma,
5588 vm_flags_t vm_flags)
5591 struct hstate *h = hstate_inode(inode);
5592 struct hugepage_subpool *spool = subpool_inode(inode);
5593 struct resv_map *resv_map;
5594 struct hugetlb_cgroup *h_cg = NULL;
5595 long gbl_reserve, regions_needed = 0;
5597 /* This should never happen */
5599 VM_WARN(1, "%s called with a negative range\n", __func__);
5604 * Only apply hugepage reservation if asked. At fault time, an
5605 * attempt will be made for VM_NORESERVE to allocate a page
5606 * without using reserves
5608 if (vm_flags & VM_NORESERVE)
5612 * Shared mappings base their reservation on the number of pages that
5613 * are already allocated on behalf of the file. Private mappings need
5614 * to reserve the full area even if read-only as mprotect() may be
5615 * called to make the mapping read-write. Assume !vma is a shm mapping
5617 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5619 * resv_map can not be NULL as hugetlb_reserve_pages is only
5620 * called for inodes for which resv_maps were created (see
5621 * hugetlbfs_get_inode).
5623 resv_map = inode_resv_map(inode);
5625 chg = region_chg(resv_map, from, to, ®ions_needed);
5628 /* Private mapping. */
5629 resv_map = resv_map_alloc();
5635 set_vma_resv_map(vma, resv_map);
5636 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5642 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
5643 chg * pages_per_huge_page(h), &h_cg) < 0)
5646 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5647 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5650 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5654 * There must be enough pages in the subpool for the mapping. If
5655 * the subpool has a minimum size, there may be some global
5656 * reservations already in place (gbl_reserve).
5658 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5659 if (gbl_reserve < 0)
5660 goto out_uncharge_cgroup;
5663 * Check enough hugepages are available for the reservation.
5664 * Hand the pages back to the subpool if there are not
5666 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
5670 * Account for the reservations made. Shared mappings record regions
5671 * that have reservations as they are shared by multiple VMAs.
5672 * When the last VMA disappears, the region map says how much
5673 * the reservation was and the page cache tells how much of
5674 * the reservation was consumed. Private mappings are per-VMA and
5675 * only the consumed reservations are tracked. When the VMA
5676 * disappears, the original reservation is the VMA size and the
5677 * consumed reservations are stored in the map. Hence, nothing
5678 * else has to be done for private mappings here
5680 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5681 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5683 if (unlikely(add < 0)) {
5684 hugetlb_acct_memory(h, -gbl_reserve);
5686 } else if (unlikely(chg > add)) {
5688 * pages in this range were added to the reserve
5689 * map between region_chg and region_add. This
5690 * indicates a race with alloc_huge_page. Adjust
5691 * the subpool and reserve counts modified above
5692 * based on the difference.
5697 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5698 * reference to h_cg->css. See comment below for detail.
5700 hugetlb_cgroup_uncharge_cgroup_rsvd(
5702 (chg - add) * pages_per_huge_page(h), h_cg);
5704 rsv_adjust = hugepage_subpool_put_pages(spool,
5706 hugetlb_acct_memory(h, -rsv_adjust);
5709 * The file_regions will hold their own reference to
5710 * h_cg->css. So we should release the reference held
5711 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5714 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5720 /* put back original number of pages, chg */
5721 (void)hugepage_subpool_put_pages(spool, chg);
5722 out_uncharge_cgroup:
5723 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5724 chg * pages_per_huge_page(h), h_cg);
5726 if (!vma || vma->vm_flags & VM_MAYSHARE)
5727 /* Only call region_abort if the region_chg succeeded but the
5728 * region_add failed or didn't run.
5730 if (chg >= 0 && add < 0)
5731 region_abort(resv_map, from, to, regions_needed);
5732 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5733 kref_put(&resv_map->refs, resv_map_release);
5737 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5740 struct hstate *h = hstate_inode(inode);
5741 struct resv_map *resv_map = inode_resv_map(inode);
5743 struct hugepage_subpool *spool = subpool_inode(inode);
5747 * Since this routine can be called in the evict inode path for all
5748 * hugetlbfs inodes, resv_map could be NULL.
5751 chg = region_del(resv_map, start, end);
5753 * region_del() can fail in the rare case where a region
5754 * must be split and another region descriptor can not be
5755 * allocated. If end == LONG_MAX, it will not fail.
5761 spin_lock(&inode->i_lock);
5762 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5763 spin_unlock(&inode->i_lock);
5766 * If the subpool has a minimum size, the number of global
5767 * reservations to be released may be adjusted.
5769 * Note that !resv_map implies freed == 0. So (chg - freed)
5770 * won't go negative.
5772 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5773 hugetlb_acct_memory(h, -gbl_reserve);
5778 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5779 static unsigned long page_table_shareable(struct vm_area_struct *svma,
5780 struct vm_area_struct *vma,
5781 unsigned long addr, pgoff_t idx)
5783 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5785 unsigned long sbase = saddr & PUD_MASK;
5786 unsigned long s_end = sbase + PUD_SIZE;
5788 /* Allow segments to share if only one is marked locked */
5789 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5790 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5793 * match the virtual addresses, permission and the alignment of the
5796 if (pmd_index(addr) != pmd_index(saddr) ||
5797 vm_flags != svm_flags ||
5798 !range_in_vma(svma, sbase, s_end))
5804 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5806 unsigned long base = addr & PUD_MASK;
5807 unsigned long end = base + PUD_SIZE;
5810 * check on proper vm_flags and page table alignment
5812 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5817 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5819 #ifdef CONFIG_USERFAULTFD
5820 if (uffd_disable_huge_pmd_share(vma))
5823 return vma_shareable(vma, addr);
5827 * Determine if start,end range within vma could be mapped by shared pmd.
5828 * If yes, adjust start and end to cover range associated with possible
5829 * shared pmd mappings.
5831 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5832 unsigned long *start, unsigned long *end)
5834 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5835 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5838 * vma needs to span at least one aligned PUD size, and the range
5839 * must be at least partially within in.
5841 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5842 (*end <= v_start) || (*start >= v_end))
5845 /* Extend the range to be PUD aligned for a worst case scenario */
5846 if (*start > v_start)
5847 *start = ALIGN_DOWN(*start, PUD_SIZE);
5850 *end = ALIGN(*end, PUD_SIZE);
5854 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5855 * and returns the corresponding pte. While this is not necessary for the
5856 * !shared pmd case because we can allocate the pmd later as well, it makes the
5857 * code much cleaner.
5859 * This routine must be called with i_mmap_rwsem held in at least read mode if
5860 * sharing is possible. For hugetlbfs, this prevents removal of any page
5861 * table entries associated with the address space. This is important as we
5862 * are setting up sharing based on existing page table entries (mappings).
5864 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5865 * huge_pte_alloc know that sharing is not possible and do not take
5866 * i_mmap_rwsem as a performance optimization. This is handled by the
5867 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5868 * only required for subsequent processing.
5870 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5871 unsigned long addr, pud_t *pud)
5873 struct address_space *mapping = vma->vm_file->f_mapping;
5874 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5876 struct vm_area_struct *svma;
5877 unsigned long saddr;
5882 i_mmap_assert_locked(mapping);
5883 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5887 saddr = page_table_shareable(svma, vma, addr, idx);
5889 spte = huge_pte_offset(svma->vm_mm, saddr,
5890 vma_mmu_pagesize(svma));
5892 get_page(virt_to_page(spte));
5901 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5902 if (pud_none(*pud)) {
5903 pud_populate(mm, pud,
5904 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5907 put_page(virt_to_page(spte));
5911 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5916 * unmap huge page backed by shared pte.
5918 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5919 * indicated by page_count > 1, unmap is achieved by clearing pud and
5920 * decrementing the ref count. If count == 1, the pte page is not shared.
5922 * Called with page table lock held and i_mmap_rwsem held in write mode.
5924 * returns: 1 successfully unmapped a shared pte page
5925 * 0 the underlying pte page is not shared, or it is the last user
5927 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5928 unsigned long *addr, pte_t *ptep)
5930 pgd_t *pgd = pgd_offset(mm, *addr);
5931 p4d_t *p4d = p4d_offset(pgd, *addr);
5932 pud_t *pud = pud_offset(p4d, *addr);
5934 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5935 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5936 if (page_count(virt_to_page(ptep)) == 1)
5940 put_page(virt_to_page(ptep));
5942 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5946 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5947 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5948 unsigned long addr, pud_t *pud)
5953 int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5954 unsigned long *addr, pte_t *ptep)
5959 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5960 unsigned long *start, unsigned long *end)
5964 bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5968 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5970 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5971 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
5972 unsigned long addr, unsigned long sz)
5979 pgd = pgd_offset(mm, addr);
5980 p4d = p4d_alloc(mm, pgd, addr);
5983 pud = pud_alloc(mm, p4d, addr);
5985 if (sz == PUD_SIZE) {
5988 BUG_ON(sz != PMD_SIZE);
5989 if (want_pmd_share(vma, addr) && pud_none(*pud))
5990 pte = huge_pmd_share(mm, vma, addr, pud);
5992 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5995 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
6001 * huge_pte_offset() - Walk the page table to resolve the hugepage
6002 * entry at address @addr
6004 * Return: Pointer to page table entry (PUD or PMD) for
6005 * address @addr, or NULL if a !p*d_present() entry is encountered and the
6006 * size @sz doesn't match the hugepage size at this level of the page
6009 pte_t *huge_pte_offset(struct mm_struct *mm,
6010 unsigned long addr, unsigned long sz)
6017 pgd = pgd_offset(mm, addr);
6018 if (!pgd_present(*pgd))
6020 p4d = p4d_offset(pgd, addr);
6021 if (!p4d_present(*p4d))
6024 pud = pud_offset(p4d, addr);
6026 /* must be pud huge, non-present or none */
6027 return (pte_t *)pud;
6028 if (!pud_present(*pud))
6030 /* must have a valid entry and size to go further */
6032 pmd = pmd_offset(pud, addr);
6033 /* must be pmd huge, non-present or none */
6034 return (pte_t *)pmd;
6037 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
6040 * These functions are overwritable if your architecture needs its own
6043 struct page * __weak
6044 follow_huge_addr(struct mm_struct *mm, unsigned long address,
6047 return ERR_PTR(-EINVAL);
6050 struct page * __weak
6051 follow_huge_pd(struct vm_area_struct *vma,
6052 unsigned long address, hugepd_t hpd, int flags, int pdshift)
6054 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
6058 struct page * __weak
6059 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
6060 pmd_t *pmd, int flags)
6062 struct page *page = NULL;
6066 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
6067 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
6068 (FOLL_PIN | FOLL_GET)))
6072 ptl = pmd_lockptr(mm, pmd);
6075 * make sure that the address range covered by this pmd is not
6076 * unmapped from other threads.
6078 if (!pmd_huge(*pmd))
6080 pte = huge_ptep_get((pte_t *)pmd);
6081 if (pte_present(pte)) {
6082 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
6084 * try_grab_page() should always succeed here, because: a) we
6085 * hold the pmd (ptl) lock, and b) we've just checked that the
6086 * huge pmd (head) page is present in the page tables. The ptl
6087 * prevents the head page and tail pages from being rearranged
6088 * in any way. So this page must be available at this point,
6089 * unless the page refcount overflowed:
6091 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
6096 if (is_hugetlb_entry_migration(pte)) {
6098 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
6102 * hwpoisoned entry is treated as no_page_table in
6103 * follow_page_mask().
6111 struct page * __weak
6112 follow_huge_pud(struct mm_struct *mm, unsigned long address,
6113 pud_t *pud, int flags)
6115 if (flags & (FOLL_GET | FOLL_PIN))
6118 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
6121 struct page * __weak
6122 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
6124 if (flags & (FOLL_GET | FOLL_PIN))
6127 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
6130 bool isolate_huge_page(struct page *page, struct list_head *list)
6134 spin_lock_irq(&hugetlb_lock);
6135 if (!PageHeadHuge(page) ||
6136 !HPageMigratable(page) ||
6137 !get_page_unless_zero(page)) {
6141 ClearHPageMigratable(page);
6142 list_move_tail(&page->lru, list);
6144 spin_unlock_irq(&hugetlb_lock);
6148 int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
6153 spin_lock_irq(&hugetlb_lock);
6154 if (PageHeadHuge(page)) {
6156 if (HPageFreed(page) || HPageMigratable(page))
6157 ret = get_page_unless_zero(page);
6161 spin_unlock_irq(&hugetlb_lock);
6165 void putback_active_hugepage(struct page *page)
6167 spin_lock_irq(&hugetlb_lock);
6168 SetHPageMigratable(page);
6169 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
6170 spin_unlock_irq(&hugetlb_lock);
6174 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
6176 struct hstate *h = page_hstate(oldpage);
6178 hugetlb_cgroup_migrate(oldpage, newpage);
6179 set_page_owner_migrate_reason(newpage, reason);
6182 * transfer temporary state of the new huge page. This is
6183 * reverse to other transitions because the newpage is going to
6184 * be final while the old one will be freed so it takes over
6185 * the temporary status.
6187 * Also note that we have to transfer the per-node surplus state
6188 * here as well otherwise the global surplus count will not match
6191 if (HPageTemporary(newpage)) {
6192 int old_nid = page_to_nid(oldpage);
6193 int new_nid = page_to_nid(newpage);
6195 SetHPageTemporary(oldpage);
6196 ClearHPageTemporary(newpage);
6199 * There is no need to transfer the per-node surplus state
6200 * when we do not cross the node.
6202 if (new_nid == old_nid)
6204 spin_lock_irq(&hugetlb_lock);
6205 if (h->surplus_huge_pages_node[old_nid]) {
6206 h->surplus_huge_pages_node[old_nid]--;
6207 h->surplus_huge_pages_node[new_nid]++;
6209 spin_unlock_irq(&hugetlb_lock);
6214 * This function will unconditionally remove all the shared pmd pgtable entries
6215 * within the specific vma for a hugetlbfs memory range.
6217 void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
6219 struct hstate *h = hstate_vma(vma);
6220 unsigned long sz = huge_page_size(h);
6221 struct mm_struct *mm = vma->vm_mm;
6222 struct mmu_notifier_range range;
6223 unsigned long address, start, end;
6227 if (!(vma->vm_flags & VM_MAYSHARE))
6230 start = ALIGN(vma->vm_start, PUD_SIZE);
6231 end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
6237 * No need to call adjust_range_if_pmd_sharing_possible(), because
6238 * we have already done the PUD_SIZE alignment.
6240 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
6242 mmu_notifier_invalidate_range_start(&range);
6243 i_mmap_lock_write(vma->vm_file->f_mapping);
6244 for (address = start; address < end; address += PUD_SIZE) {
6245 unsigned long tmp = address;
6247 ptep = huge_pte_offset(mm, address, sz);
6250 ptl = huge_pte_lock(h, mm, ptep);
6251 /* We don't want 'address' to be changed */
6252 huge_pmd_unshare(mm, vma, &tmp, ptep);
6255 flush_hugetlb_tlb_range(vma, start, end);
6256 i_mmap_unlock_write(vma->vm_file->f_mapping);
6258 * No need to call mmu_notifier_invalidate_range(), see
6259 * Documentation/vm/mmu_notifier.rst.
6261 mmu_notifier_invalidate_range_end(&range);
6265 static bool cma_reserve_called __initdata;
6267 static int __init cmdline_parse_hugetlb_cma(char *p)
6269 hugetlb_cma_size = memparse(p, &p);
6273 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
6275 void __init hugetlb_cma_reserve(int order)
6277 unsigned long size, reserved, per_node;
6280 cma_reserve_called = true;
6282 if (!hugetlb_cma_size)
6285 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
6286 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
6287 (PAGE_SIZE << order) / SZ_1M);
6292 * If 3 GB area is requested on a machine with 4 numa nodes,
6293 * let's allocate 1 GB on first three nodes and ignore the last one.
6295 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
6296 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
6297 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
6300 for_each_node_state(nid, N_ONLINE) {
6302 char name[CMA_MAX_NAME];
6304 size = min(per_node, hugetlb_cma_size - reserved);
6305 size = round_up(size, PAGE_SIZE << order);
6307 snprintf(name, sizeof(name), "hugetlb%d", nid);
6308 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
6310 &hugetlb_cma[nid], nid);
6312 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
6318 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
6321 if (reserved >= hugetlb_cma_size)
6326 void __init hugetlb_cma_check(void)
6328 if (!hugetlb_cma_size || cma_reserve_called)
6331 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
6334 #endif /* CONFIG_CMA */