2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.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/bootmem.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
38 int hugepages_treat_as_movable;
40 int hugetlb_max_hstate __read_mostly;
41 unsigned int default_hstate_idx;
42 struct hstate hstates[HUGE_MAX_HSTATE];
44 __initdata LIST_HEAD(huge_boot_pages);
46 /* for command line parsing */
47 static struct hstate * __initdata parsed_hstate;
48 static unsigned long __initdata default_hstate_max_huge_pages;
49 static unsigned long __initdata default_hstate_size;
52 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
53 * free_huge_pages, and surplus_huge_pages.
55 DEFINE_SPINLOCK(hugetlb_lock);
58 * Serializes faults on the same logical page. This is used to
59 * prevent spurious OOMs when the hugepage pool is fully utilized.
61 static int num_fault_mutexes;
62 static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;
64 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
66 bool free = (spool->count == 0) && (spool->used_hpages == 0);
68 spin_unlock(&spool->lock);
70 /* If no pages are used, and no other handles to the subpool
71 * remain, free the subpool the subpool remain */
76 struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
78 struct hugepage_subpool *spool;
80 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
84 spin_lock_init(&spool->lock);
86 spool->max_hpages = nr_blocks;
91 void hugepage_put_subpool(struct hugepage_subpool *spool)
93 spin_lock(&spool->lock);
94 BUG_ON(!spool->count);
96 unlock_or_release_subpool(spool);
99 static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
107 spin_lock(&spool->lock);
108 if ((spool->used_hpages + delta) <= spool->max_hpages) {
109 spool->used_hpages += delta;
113 spin_unlock(&spool->lock);
118 static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
124 spin_lock(&spool->lock);
125 spool->used_hpages -= delta;
126 /* If hugetlbfs_put_super couldn't free spool due to
127 * an outstanding quota reference, free it now. */
128 unlock_or_release_subpool(spool);
131 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
133 return HUGETLBFS_SB(inode->i_sb)->spool;
136 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
138 return subpool_inode(file_inode(vma->vm_file));
142 * Region tracking -- allows tracking of reservations and instantiated pages
143 * across the pages in a mapping.
145 * The region data structures are embedded into a resv_map and
146 * protected by a resv_map's lock
149 struct list_head link;
154 static long region_add(struct resv_map *resv, long f, long t)
156 struct list_head *head = &resv->regions;
157 struct file_region *rg, *nrg, *trg;
159 spin_lock(&resv->lock);
160 /* Locate the region we are either in or before. */
161 list_for_each_entry(rg, head, link)
165 /* Round our left edge to the current segment if it encloses us. */
169 /* Check for and consume any regions we now overlap with. */
171 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
172 if (&rg->link == head)
177 /* If this area reaches higher then extend our area to
178 * include it completely. If this is not the first area
179 * which we intend to reuse, free it. */
189 spin_unlock(&resv->lock);
193 static long region_chg(struct resv_map *resv, long f, long t)
195 struct list_head *head = &resv->regions;
196 struct file_region *rg, *nrg = NULL;
200 spin_lock(&resv->lock);
201 /* Locate the region we are before or in. */
202 list_for_each_entry(rg, head, link)
206 /* If we are below the current region then a new region is required.
207 * Subtle, allocate a new region at the position but make it zero
208 * size such that we can guarantee to record the reservation. */
209 if (&rg->link == head || t < rg->from) {
211 spin_unlock(&resv->lock);
212 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
218 INIT_LIST_HEAD(&nrg->link);
222 list_add(&nrg->link, rg->link.prev);
227 /* Round our left edge to the current segment if it encloses us. */
232 /* Check for and consume any regions we now overlap with. */
233 list_for_each_entry(rg, rg->link.prev, link) {
234 if (&rg->link == head)
239 /* We overlap with this area, if it extends further than
240 * us then we must extend ourselves. Account for its
241 * existing reservation. */
246 chg -= rg->to - rg->from;
250 spin_unlock(&resv->lock);
251 /* We already know we raced and no longer need the new region */
255 spin_unlock(&resv->lock);
259 static long region_truncate(struct resv_map *resv, long end)
261 struct list_head *head = &resv->regions;
262 struct file_region *rg, *trg;
265 spin_lock(&resv->lock);
266 /* Locate the region we are either in or before. */
267 list_for_each_entry(rg, head, link)
270 if (&rg->link == head)
273 /* If we are in the middle of a region then adjust it. */
274 if (end > rg->from) {
277 rg = list_entry(rg->link.next, typeof(*rg), link);
280 /* Drop any remaining regions. */
281 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
282 if (&rg->link == head)
284 chg += rg->to - rg->from;
290 spin_unlock(&resv->lock);
294 static long region_count(struct resv_map *resv, long f, long t)
296 struct list_head *head = &resv->regions;
297 struct file_region *rg;
300 spin_lock(&resv->lock);
301 /* Locate each segment we overlap with, and count that overlap. */
302 list_for_each_entry(rg, head, link) {
311 seg_from = max(rg->from, f);
312 seg_to = min(rg->to, t);
314 chg += seg_to - seg_from;
316 spin_unlock(&resv->lock);
322 * Convert the address within this vma to the page offset within
323 * the mapping, in pagecache page units; huge pages here.
325 static pgoff_t vma_hugecache_offset(struct hstate *h,
326 struct vm_area_struct *vma, unsigned long address)
328 return ((address - vma->vm_start) >> huge_page_shift(h)) +
329 (vma->vm_pgoff >> huge_page_order(h));
332 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
333 unsigned long address)
335 return vma_hugecache_offset(hstate_vma(vma), vma, address);
339 * Return the size of the pages allocated when backing a VMA. In the majority
340 * cases this will be same size as used by the page table entries.
342 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
344 struct hstate *hstate;
346 if (!is_vm_hugetlb_page(vma))
349 hstate = hstate_vma(vma);
351 return 1UL << huge_page_shift(hstate);
353 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
356 * Return the page size being used by the MMU to back a VMA. In the majority
357 * of cases, the page size used by the kernel matches the MMU size. On
358 * architectures where it differs, an architecture-specific version of this
359 * function is required.
361 #ifndef vma_mmu_pagesize
362 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
364 return vma_kernel_pagesize(vma);
369 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
370 * bits of the reservation map pointer, which are always clear due to
373 #define HPAGE_RESV_OWNER (1UL << 0)
374 #define HPAGE_RESV_UNMAPPED (1UL << 1)
375 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
378 * These helpers are used to track how many pages are reserved for
379 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
380 * is guaranteed to have their future faults succeed.
382 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
383 * the reserve counters are updated with the hugetlb_lock held. It is safe
384 * to reset the VMA at fork() time as it is not in use yet and there is no
385 * chance of the global counters getting corrupted as a result of the values.
387 * The private mapping reservation is represented in a subtly different
388 * manner to a shared mapping. A shared mapping has a region map associated
389 * with the underlying file, this region map represents the backing file
390 * pages which have ever had a reservation assigned which this persists even
391 * after the page is instantiated. A private mapping has a region map
392 * associated with the original mmap which is attached to all VMAs which
393 * reference it, this region map represents those offsets which have consumed
394 * reservation ie. where pages have been instantiated.
396 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
398 return (unsigned long)vma->vm_private_data;
401 static void set_vma_private_data(struct vm_area_struct *vma,
404 vma->vm_private_data = (void *)value;
407 struct resv_map *resv_map_alloc(void)
409 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
413 kref_init(&resv_map->refs);
414 spin_lock_init(&resv_map->lock);
415 INIT_LIST_HEAD(&resv_map->regions);
420 void resv_map_release(struct kref *ref)
422 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
424 /* Clear out any active regions before we release the map. */
425 region_truncate(resv_map, 0);
429 static inline struct resv_map *inode_resv_map(struct inode *inode)
431 return inode->i_mapping->private_data;
434 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
436 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
437 if (vma->vm_flags & VM_MAYSHARE) {
438 struct address_space *mapping = vma->vm_file->f_mapping;
439 struct inode *inode = mapping->host;
441 return inode_resv_map(inode);
444 return (struct resv_map *)(get_vma_private_data(vma) &
449 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
451 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
452 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
454 set_vma_private_data(vma, (get_vma_private_data(vma) &
455 HPAGE_RESV_MASK) | (unsigned long)map);
458 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
460 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
461 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
463 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
466 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
468 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
470 return (get_vma_private_data(vma) & flag) != 0;
473 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
474 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
476 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
477 if (!(vma->vm_flags & VM_MAYSHARE))
478 vma->vm_private_data = (void *)0;
481 /* Returns true if the VMA has associated reserve pages */
482 static int vma_has_reserves(struct vm_area_struct *vma, long chg)
484 if (vma->vm_flags & VM_NORESERVE) {
486 * This address is already reserved by other process(chg == 0),
487 * so, we should decrement reserved count. Without decrementing,
488 * reserve count remains after releasing inode, because this
489 * allocated page will go into page cache and is regarded as
490 * coming from reserved pool in releasing step. Currently, we
491 * don't have any other solution to deal with this situation
492 * properly, so add work-around here.
494 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
500 /* Shared mappings always use reserves */
501 if (vma->vm_flags & VM_MAYSHARE)
505 * Only the process that called mmap() has reserves for
508 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
514 static void enqueue_huge_page(struct hstate *h, struct page *page)
516 int nid = page_to_nid(page);
517 list_move(&page->lru, &h->hugepage_freelists[nid]);
518 h->free_huge_pages++;
519 h->free_huge_pages_node[nid]++;
522 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
526 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
527 if (!is_migrate_isolate_page(page))
530 * if 'non-isolated free hugepage' not found on the list,
531 * the allocation fails.
533 if (&h->hugepage_freelists[nid] == &page->lru)
535 list_move(&page->lru, &h->hugepage_activelist);
536 set_page_refcounted(page);
537 h->free_huge_pages--;
538 h->free_huge_pages_node[nid]--;
542 /* Movability of hugepages depends on migration support. */
543 static inline gfp_t htlb_alloc_mask(struct hstate *h)
545 if (hugepages_treat_as_movable || hugepage_migration_supported(h))
546 return GFP_HIGHUSER_MOVABLE;
551 static struct page *dequeue_huge_page_vma(struct hstate *h,
552 struct vm_area_struct *vma,
553 unsigned long address, int avoid_reserve,
556 struct page *page = NULL;
557 struct mempolicy *mpol;
558 nodemask_t *nodemask;
559 struct zonelist *zonelist;
562 unsigned int cpuset_mems_cookie;
565 * A child process with MAP_PRIVATE mappings created by their parent
566 * have no page reserves. This check ensures that reservations are
567 * not "stolen". The child may still get SIGKILLed
569 if (!vma_has_reserves(vma, chg) &&
570 h->free_huge_pages - h->resv_huge_pages == 0)
573 /* If reserves cannot be used, ensure enough pages are in the pool */
574 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
578 cpuset_mems_cookie = read_mems_allowed_begin();
579 zonelist = huge_zonelist(vma, address,
580 htlb_alloc_mask(h), &mpol, &nodemask);
582 for_each_zone_zonelist_nodemask(zone, z, zonelist,
583 MAX_NR_ZONES - 1, nodemask) {
584 if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
585 page = dequeue_huge_page_node(h, zone_to_nid(zone));
589 if (!vma_has_reserves(vma, chg))
592 SetPagePrivate(page);
593 h->resv_huge_pages--;
600 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
609 * common helper functions for hstate_next_node_to_{alloc|free}.
610 * We may have allocated or freed a huge page based on a different
611 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
612 * be outside of *nodes_allowed. Ensure that we use an allowed
613 * node for alloc or free.
615 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
617 nid = next_node(nid, *nodes_allowed);
618 if (nid == MAX_NUMNODES)
619 nid = first_node(*nodes_allowed);
620 VM_BUG_ON(nid >= MAX_NUMNODES);
625 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
627 if (!node_isset(nid, *nodes_allowed))
628 nid = next_node_allowed(nid, nodes_allowed);
633 * returns the previously saved node ["this node"] from which to
634 * allocate a persistent huge page for the pool and advance the
635 * next node from which to allocate, handling wrap at end of node
638 static int hstate_next_node_to_alloc(struct hstate *h,
639 nodemask_t *nodes_allowed)
643 VM_BUG_ON(!nodes_allowed);
645 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
646 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
652 * helper for free_pool_huge_page() - return the previously saved
653 * node ["this node"] from which to free a huge page. Advance the
654 * next node id whether or not we find a free huge page to free so
655 * that the next attempt to free addresses the next node.
657 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
661 VM_BUG_ON(!nodes_allowed);
663 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
664 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
669 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
670 for (nr_nodes = nodes_weight(*mask); \
672 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
675 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
676 for (nr_nodes = nodes_weight(*mask); \
678 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
681 #if defined(CONFIG_CMA) && defined(CONFIG_X86_64)
682 static void destroy_compound_gigantic_page(struct page *page,
686 int nr_pages = 1 << order;
687 struct page *p = page + 1;
689 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
691 set_page_refcounted(p);
692 p->first_page = NULL;
695 set_compound_order(page, 0);
696 __ClearPageHead(page);
699 static void free_gigantic_page(struct page *page, unsigned order)
701 free_contig_range(page_to_pfn(page), 1 << order);
704 static int __alloc_gigantic_page(unsigned long start_pfn,
705 unsigned long nr_pages)
707 unsigned long end_pfn = start_pfn + nr_pages;
708 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
711 static bool pfn_range_valid_gigantic(unsigned long start_pfn,
712 unsigned long nr_pages)
714 unsigned long i, end_pfn = start_pfn + nr_pages;
717 for (i = start_pfn; i < end_pfn; i++) {
721 page = pfn_to_page(i);
723 if (PageReserved(page))
726 if (page_count(page) > 0)
736 static bool zone_spans_last_pfn(const struct zone *zone,
737 unsigned long start_pfn, unsigned long nr_pages)
739 unsigned long last_pfn = start_pfn + nr_pages - 1;
740 return zone_spans_pfn(zone, last_pfn);
743 static struct page *alloc_gigantic_page(int nid, unsigned order)
745 unsigned long nr_pages = 1 << order;
746 unsigned long ret, pfn, flags;
749 z = NODE_DATA(nid)->node_zones;
750 for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
751 spin_lock_irqsave(&z->lock, flags);
753 pfn = ALIGN(z->zone_start_pfn, nr_pages);
754 while (zone_spans_last_pfn(z, pfn, nr_pages)) {
755 if (pfn_range_valid_gigantic(pfn, nr_pages)) {
757 * We release the zone lock here because
758 * alloc_contig_range() will also lock the zone
759 * at some point. If there's an allocation
760 * spinning on this lock, it may win the race
761 * and cause alloc_contig_range() to fail...
763 spin_unlock_irqrestore(&z->lock, flags);
764 ret = __alloc_gigantic_page(pfn, nr_pages);
766 return pfn_to_page(pfn);
767 spin_lock_irqsave(&z->lock, flags);
772 spin_unlock_irqrestore(&z->lock, flags);
778 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
779 static void prep_compound_gigantic_page(struct page *page, unsigned long order);
781 static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
785 page = alloc_gigantic_page(nid, huge_page_order(h));
787 prep_compound_gigantic_page(page, huge_page_order(h));
788 prep_new_huge_page(h, page, nid);
794 static int alloc_fresh_gigantic_page(struct hstate *h,
795 nodemask_t *nodes_allowed)
797 struct page *page = NULL;
800 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
801 page = alloc_fresh_gigantic_page_node(h, node);
809 static inline bool gigantic_page_supported(void) { return true; }
811 static inline bool gigantic_page_supported(void) { return false; }
812 static inline void free_gigantic_page(struct page *page, unsigned order) { }
813 static inline void destroy_compound_gigantic_page(struct page *page,
814 unsigned long order) { }
815 static inline int alloc_fresh_gigantic_page(struct hstate *h,
816 nodemask_t *nodes_allowed) { return 0; }
819 static void update_and_free_page(struct hstate *h, struct page *page)
823 if (hstate_is_gigantic(h) && !gigantic_page_supported())
827 h->nr_huge_pages_node[page_to_nid(page)]--;
828 for (i = 0; i < pages_per_huge_page(h); i++) {
829 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
830 1 << PG_referenced | 1 << PG_dirty |
831 1 << PG_active | 1 << PG_private |
834 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
835 set_compound_page_dtor(page, NULL);
836 set_page_refcounted(page);
837 if (hstate_is_gigantic(h)) {
838 destroy_compound_gigantic_page(page, huge_page_order(h));
839 free_gigantic_page(page, huge_page_order(h));
841 arch_release_hugepage(page);
842 __free_pages(page, huge_page_order(h));
846 struct hstate *size_to_hstate(unsigned long size)
851 if (huge_page_size(h) == size)
857 void free_huge_page(struct page *page)
860 * Can't pass hstate in here because it is called from the
861 * compound page destructor.
863 struct hstate *h = page_hstate(page);
864 int nid = page_to_nid(page);
865 struct hugepage_subpool *spool =
866 (struct hugepage_subpool *)page_private(page);
867 bool restore_reserve;
869 set_page_private(page, 0);
870 page->mapping = NULL;
871 BUG_ON(page_count(page));
872 BUG_ON(page_mapcount(page));
873 restore_reserve = PagePrivate(page);
874 ClearPagePrivate(page);
876 spin_lock(&hugetlb_lock);
877 hugetlb_cgroup_uncharge_page(hstate_index(h),
878 pages_per_huge_page(h), page);
880 h->resv_huge_pages++;
882 if (h->surplus_huge_pages_node[nid]) {
883 /* remove the page from active list */
884 list_del(&page->lru);
885 update_and_free_page(h, page);
886 h->surplus_huge_pages--;
887 h->surplus_huge_pages_node[nid]--;
889 arch_clear_hugepage_flags(page);
890 enqueue_huge_page(h, page);
892 spin_unlock(&hugetlb_lock);
893 hugepage_subpool_put_pages(spool, 1);
896 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
898 INIT_LIST_HEAD(&page->lru);
899 set_compound_page_dtor(page, free_huge_page);
900 spin_lock(&hugetlb_lock);
901 set_hugetlb_cgroup(page, NULL);
903 h->nr_huge_pages_node[nid]++;
904 spin_unlock(&hugetlb_lock);
905 put_page(page); /* free it into the hugepage allocator */
908 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
911 int nr_pages = 1 << order;
912 struct page *p = page + 1;
914 /* we rely on prep_new_huge_page to set the destructor */
915 set_compound_order(page, order);
917 __ClearPageReserved(page);
918 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
920 * For gigantic hugepages allocated through bootmem at
921 * boot, it's safer to be consistent with the not-gigantic
922 * hugepages and clear the PG_reserved bit from all tail pages
923 * too. Otherwse drivers using get_user_pages() to access tail
924 * pages may get the reference counting wrong if they see
925 * PG_reserved set on a tail page (despite the head page not
926 * having PG_reserved set). Enforcing this consistency between
927 * head and tail pages allows drivers to optimize away a check
928 * on the head page when they need know if put_page() is needed
929 * after get_user_pages().
931 __ClearPageReserved(p);
932 set_page_count(p, 0);
933 p->first_page = page;
934 /* Make sure p->first_page is always valid for PageTail() */
941 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
942 * transparent huge pages. See the PageTransHuge() documentation for more
945 int PageHuge(struct page *page)
947 if (!PageCompound(page))
950 page = compound_head(page);
951 return get_compound_page_dtor(page) == free_huge_page;
953 EXPORT_SYMBOL_GPL(PageHuge);
956 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
957 * normal or transparent huge pages.
959 int PageHeadHuge(struct page *page_head)
961 if (!PageHead(page_head))
964 return get_compound_page_dtor(page_head) == free_huge_page;
967 pgoff_t __basepage_index(struct page *page)
969 struct page *page_head = compound_head(page);
970 pgoff_t index = page_index(page_head);
971 unsigned long compound_idx;
973 if (!PageHuge(page_head))
974 return page_index(page);
976 if (compound_order(page_head) >= MAX_ORDER)
977 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
979 compound_idx = page - page_head;
981 return (index << compound_order(page_head)) + compound_idx;
984 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
988 page = alloc_pages_exact_node(nid,
989 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
990 __GFP_REPEAT|__GFP_NOWARN,
993 if (arch_prepare_hugepage(page)) {
994 __free_pages(page, huge_page_order(h));
997 prep_new_huge_page(h, page, nid);
1003 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1009 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1010 page = alloc_fresh_huge_page_node(h, node);
1018 count_vm_event(HTLB_BUDDY_PGALLOC);
1020 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1026 * Free huge page from pool from next node to free.
1027 * Attempt to keep persistent huge pages more or less
1028 * balanced over allowed nodes.
1029 * Called with hugetlb_lock locked.
1031 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1037 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1039 * If we're returning unused surplus pages, only examine
1040 * nodes with surplus pages.
1042 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1043 !list_empty(&h->hugepage_freelists[node])) {
1045 list_entry(h->hugepage_freelists[node].next,
1047 list_del(&page->lru);
1048 h->free_huge_pages--;
1049 h->free_huge_pages_node[node]--;
1051 h->surplus_huge_pages--;
1052 h->surplus_huge_pages_node[node]--;
1054 update_and_free_page(h, page);
1064 * Dissolve a given free hugepage into free buddy pages. This function does
1065 * nothing for in-use (including surplus) hugepages.
1067 static void dissolve_free_huge_page(struct page *page)
1069 spin_lock(&hugetlb_lock);
1070 if (PageHuge(page) && !page_count(page)) {
1071 struct hstate *h = page_hstate(page);
1072 int nid = page_to_nid(page);
1073 list_del(&page->lru);
1074 h->free_huge_pages--;
1075 h->free_huge_pages_node[nid]--;
1076 update_and_free_page(h, page);
1078 spin_unlock(&hugetlb_lock);
1082 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1083 * make specified memory blocks removable from the system.
1084 * Note that start_pfn should aligned with (minimum) hugepage size.
1086 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1088 unsigned int order = 8 * sizeof(void *);
1092 if (!hugepages_supported())
1095 /* Set scan step to minimum hugepage size */
1097 if (order > huge_page_order(h))
1098 order = huge_page_order(h);
1099 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
1100 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
1101 dissolve_free_huge_page(pfn_to_page(pfn));
1104 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
1109 if (hstate_is_gigantic(h))
1113 * Assume we will successfully allocate the surplus page to
1114 * prevent racing processes from causing the surplus to exceed
1117 * This however introduces a different race, where a process B
1118 * tries to grow the static hugepage pool while alloc_pages() is
1119 * called by process A. B will only examine the per-node
1120 * counters in determining if surplus huge pages can be
1121 * converted to normal huge pages in adjust_pool_surplus(). A
1122 * won't be able to increment the per-node counter, until the
1123 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1124 * no more huge pages can be converted from surplus to normal
1125 * state (and doesn't try to convert again). Thus, we have a
1126 * case where a surplus huge page exists, the pool is grown, and
1127 * the surplus huge page still exists after, even though it
1128 * should just have been converted to a normal huge page. This
1129 * does not leak memory, though, as the hugepage will be freed
1130 * once it is out of use. It also does not allow the counters to
1131 * go out of whack in adjust_pool_surplus() as we don't modify
1132 * the node values until we've gotten the hugepage and only the
1133 * per-node value is checked there.
1135 spin_lock(&hugetlb_lock);
1136 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1137 spin_unlock(&hugetlb_lock);
1141 h->surplus_huge_pages++;
1143 spin_unlock(&hugetlb_lock);
1145 if (nid == NUMA_NO_NODE)
1146 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
1147 __GFP_REPEAT|__GFP_NOWARN,
1148 huge_page_order(h));
1150 page = alloc_pages_exact_node(nid,
1151 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1152 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
1154 if (page && arch_prepare_hugepage(page)) {
1155 __free_pages(page, huge_page_order(h));
1159 spin_lock(&hugetlb_lock);
1161 INIT_LIST_HEAD(&page->lru);
1162 r_nid = page_to_nid(page);
1163 set_compound_page_dtor(page, free_huge_page);
1164 set_hugetlb_cgroup(page, NULL);
1166 * We incremented the global counters already
1168 h->nr_huge_pages_node[r_nid]++;
1169 h->surplus_huge_pages_node[r_nid]++;
1170 __count_vm_event(HTLB_BUDDY_PGALLOC);
1173 h->surplus_huge_pages--;
1174 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1176 spin_unlock(&hugetlb_lock);
1182 * This allocation function is useful in the context where vma is irrelevant.
1183 * E.g. soft-offlining uses this function because it only cares physical
1184 * address of error page.
1186 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1188 struct page *page = NULL;
1190 spin_lock(&hugetlb_lock);
1191 if (h->free_huge_pages - h->resv_huge_pages > 0)
1192 page = dequeue_huge_page_node(h, nid);
1193 spin_unlock(&hugetlb_lock);
1196 page = alloc_buddy_huge_page(h, nid);
1202 * Increase the hugetlb pool such that it can accommodate a reservation
1205 static int gather_surplus_pages(struct hstate *h, int delta)
1207 struct list_head surplus_list;
1208 struct page *page, *tmp;
1210 int needed, allocated;
1211 bool alloc_ok = true;
1213 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1215 h->resv_huge_pages += delta;
1220 INIT_LIST_HEAD(&surplus_list);
1224 spin_unlock(&hugetlb_lock);
1225 for (i = 0; i < needed; i++) {
1226 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1231 list_add(&page->lru, &surplus_list);
1236 * After retaking hugetlb_lock, we need to recalculate 'needed'
1237 * because either resv_huge_pages or free_huge_pages may have changed.
1239 spin_lock(&hugetlb_lock);
1240 needed = (h->resv_huge_pages + delta) -
1241 (h->free_huge_pages + allocated);
1246 * We were not able to allocate enough pages to
1247 * satisfy the entire reservation so we free what
1248 * we've allocated so far.
1253 * The surplus_list now contains _at_least_ the number of extra pages
1254 * needed to accommodate the reservation. Add the appropriate number
1255 * of pages to the hugetlb pool and free the extras back to the buddy
1256 * allocator. Commit the entire reservation here to prevent another
1257 * process from stealing the pages as they are added to the pool but
1258 * before they are reserved.
1260 needed += allocated;
1261 h->resv_huge_pages += delta;
1264 /* Free the needed pages to the hugetlb pool */
1265 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1269 * This page is now managed by the hugetlb allocator and has
1270 * no users -- drop the buddy allocator's reference.
1272 put_page_testzero(page);
1273 VM_BUG_ON_PAGE(page_count(page), page);
1274 enqueue_huge_page(h, page);
1277 spin_unlock(&hugetlb_lock);
1279 /* Free unnecessary surplus pages to the buddy allocator */
1280 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1282 spin_lock(&hugetlb_lock);
1288 * When releasing a hugetlb pool reservation, any surplus pages that were
1289 * allocated to satisfy the reservation must be explicitly freed if they were
1291 * Called with hugetlb_lock held.
1293 static void return_unused_surplus_pages(struct hstate *h,
1294 unsigned long unused_resv_pages)
1296 unsigned long nr_pages;
1298 /* Uncommit the reservation */
1299 h->resv_huge_pages -= unused_resv_pages;
1301 /* Cannot return gigantic pages currently */
1302 if (hstate_is_gigantic(h))
1305 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1308 * We want to release as many surplus pages as possible, spread
1309 * evenly across all nodes with memory. Iterate across these nodes
1310 * until we can no longer free unreserved surplus pages. This occurs
1311 * when the nodes with surplus pages have no free pages.
1312 * free_pool_huge_page() will balance the the freed pages across the
1313 * on-line nodes with memory and will handle the hstate accounting.
1315 while (nr_pages--) {
1316 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1318 cond_resched_lock(&hugetlb_lock);
1323 * Determine if the huge page at addr within the vma has an associated
1324 * reservation. Where it does not we will need to logically increase
1325 * reservation and actually increase subpool usage before an allocation
1326 * can occur. Where any new reservation would be required the
1327 * reservation change is prepared, but not committed. Once the page
1328 * has been allocated from the subpool and instantiated the change should
1329 * be committed via vma_commit_reservation. No action is required on
1332 static long vma_needs_reservation(struct hstate *h,
1333 struct vm_area_struct *vma, unsigned long addr)
1335 struct resv_map *resv;
1339 resv = vma_resv_map(vma);
1343 idx = vma_hugecache_offset(h, vma, addr);
1344 chg = region_chg(resv, idx, idx + 1);
1346 if (vma->vm_flags & VM_MAYSHARE)
1349 return chg < 0 ? chg : 0;
1351 static void vma_commit_reservation(struct hstate *h,
1352 struct vm_area_struct *vma, unsigned long addr)
1354 struct resv_map *resv;
1357 resv = vma_resv_map(vma);
1361 idx = vma_hugecache_offset(h, vma, addr);
1362 region_add(resv, idx, idx + 1);
1365 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1366 unsigned long addr, int avoid_reserve)
1368 struct hugepage_subpool *spool = subpool_vma(vma);
1369 struct hstate *h = hstate_vma(vma);
1373 struct hugetlb_cgroup *h_cg;
1375 idx = hstate_index(h);
1377 * Processes that did not create the mapping will have no
1378 * reserves and will not have accounted against subpool
1379 * limit. Check that the subpool limit can be made before
1380 * satisfying the allocation MAP_NORESERVE mappings may also
1381 * need pages and subpool limit allocated allocated if no reserve
1384 chg = vma_needs_reservation(h, vma, addr);
1386 return ERR_PTR(-ENOMEM);
1387 if (chg || avoid_reserve)
1388 if (hugepage_subpool_get_pages(spool, 1))
1389 return ERR_PTR(-ENOSPC);
1391 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1393 goto out_subpool_put;
1395 spin_lock(&hugetlb_lock);
1396 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1398 spin_unlock(&hugetlb_lock);
1399 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1401 goto out_uncharge_cgroup;
1403 spin_lock(&hugetlb_lock);
1404 list_move(&page->lru, &h->hugepage_activelist);
1407 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1408 spin_unlock(&hugetlb_lock);
1410 set_page_private(page, (unsigned long)spool);
1412 vma_commit_reservation(h, vma, addr);
1415 out_uncharge_cgroup:
1416 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
1418 if (chg || avoid_reserve)
1419 hugepage_subpool_put_pages(spool, 1);
1420 return ERR_PTR(-ENOSPC);
1424 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1425 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1426 * where no ERR_VALUE is expected to be returned.
1428 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1429 unsigned long addr, int avoid_reserve)
1431 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1437 int __weak alloc_bootmem_huge_page(struct hstate *h)
1439 struct huge_bootmem_page *m;
1442 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1445 addr = memblock_virt_alloc_try_nid_nopanic(
1446 huge_page_size(h), huge_page_size(h),
1447 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1450 * Use the beginning of the huge page to store the
1451 * huge_bootmem_page struct (until gather_bootmem
1452 * puts them into the mem_map).
1461 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
1462 /* Put them into a private list first because mem_map is not up yet */
1463 list_add(&m->list, &huge_boot_pages);
1468 static void __init prep_compound_huge_page(struct page *page, int order)
1470 if (unlikely(order > (MAX_ORDER - 1)))
1471 prep_compound_gigantic_page(page, order);
1473 prep_compound_page(page, order);
1476 /* Put bootmem huge pages into the standard lists after mem_map is up */
1477 static void __init gather_bootmem_prealloc(void)
1479 struct huge_bootmem_page *m;
1481 list_for_each_entry(m, &huge_boot_pages, list) {
1482 struct hstate *h = m->hstate;
1485 #ifdef CONFIG_HIGHMEM
1486 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1487 memblock_free_late(__pa(m),
1488 sizeof(struct huge_bootmem_page));
1490 page = virt_to_page(m);
1492 WARN_ON(page_count(page) != 1);
1493 prep_compound_huge_page(page, h->order);
1494 WARN_ON(PageReserved(page));
1495 prep_new_huge_page(h, page, page_to_nid(page));
1497 * If we had gigantic hugepages allocated at boot time, we need
1498 * to restore the 'stolen' pages to totalram_pages in order to
1499 * fix confusing memory reports from free(1) and another
1500 * side-effects, like CommitLimit going negative.
1502 if (hstate_is_gigantic(h))
1503 adjust_managed_page_count(page, 1 << h->order);
1507 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1511 for (i = 0; i < h->max_huge_pages; ++i) {
1512 if (hstate_is_gigantic(h)) {
1513 if (!alloc_bootmem_huge_page(h))
1515 } else if (!alloc_fresh_huge_page(h,
1516 &node_states[N_MEMORY]))
1519 h->max_huge_pages = i;
1522 static void __init hugetlb_init_hstates(void)
1526 for_each_hstate(h) {
1527 /* oversize hugepages were init'ed in early boot */
1528 if (!hstate_is_gigantic(h))
1529 hugetlb_hstate_alloc_pages(h);
1533 static char * __init memfmt(char *buf, unsigned long n)
1535 if (n >= (1UL << 30))
1536 sprintf(buf, "%lu GB", n >> 30);
1537 else if (n >= (1UL << 20))
1538 sprintf(buf, "%lu MB", n >> 20);
1540 sprintf(buf, "%lu KB", n >> 10);
1544 static void __init report_hugepages(void)
1548 for_each_hstate(h) {
1550 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1551 memfmt(buf, huge_page_size(h)),
1552 h->free_huge_pages);
1556 #ifdef CONFIG_HIGHMEM
1557 static void try_to_free_low(struct hstate *h, unsigned long count,
1558 nodemask_t *nodes_allowed)
1562 if (hstate_is_gigantic(h))
1565 for_each_node_mask(i, *nodes_allowed) {
1566 struct page *page, *next;
1567 struct list_head *freel = &h->hugepage_freelists[i];
1568 list_for_each_entry_safe(page, next, freel, lru) {
1569 if (count >= h->nr_huge_pages)
1571 if (PageHighMem(page))
1573 list_del(&page->lru);
1574 update_and_free_page(h, page);
1575 h->free_huge_pages--;
1576 h->free_huge_pages_node[page_to_nid(page)]--;
1581 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1582 nodemask_t *nodes_allowed)
1588 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1589 * balanced by operating on them in a round-robin fashion.
1590 * Returns 1 if an adjustment was made.
1592 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1597 VM_BUG_ON(delta != -1 && delta != 1);
1600 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1601 if (h->surplus_huge_pages_node[node])
1605 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1606 if (h->surplus_huge_pages_node[node] <
1607 h->nr_huge_pages_node[node])
1614 h->surplus_huge_pages += delta;
1615 h->surplus_huge_pages_node[node] += delta;
1619 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1620 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1621 nodemask_t *nodes_allowed)
1623 unsigned long min_count, ret;
1625 if (hstate_is_gigantic(h) && !gigantic_page_supported())
1626 return h->max_huge_pages;
1629 * Increase the pool size
1630 * First take pages out of surplus state. Then make up the
1631 * remaining difference by allocating fresh huge pages.
1633 * We might race with alloc_buddy_huge_page() here and be unable
1634 * to convert a surplus huge page to a normal huge page. That is
1635 * not critical, though, it just means the overall size of the
1636 * pool might be one hugepage larger than it needs to be, but
1637 * within all the constraints specified by the sysctls.
1639 spin_lock(&hugetlb_lock);
1640 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1641 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1645 while (count > persistent_huge_pages(h)) {
1647 * If this allocation races such that we no longer need the
1648 * page, free_huge_page will handle it by freeing the page
1649 * and reducing the surplus.
1651 spin_unlock(&hugetlb_lock);
1652 if (hstate_is_gigantic(h))
1653 ret = alloc_fresh_gigantic_page(h, nodes_allowed);
1655 ret = alloc_fresh_huge_page(h, nodes_allowed);
1656 spin_lock(&hugetlb_lock);
1660 /* Bail for signals. Probably ctrl-c from user */
1661 if (signal_pending(current))
1666 * Decrease the pool size
1667 * First return free pages to the buddy allocator (being careful
1668 * to keep enough around to satisfy reservations). Then place
1669 * pages into surplus state as needed so the pool will shrink
1670 * to the desired size as pages become free.
1672 * By placing pages into the surplus state independent of the
1673 * overcommit value, we are allowing the surplus pool size to
1674 * exceed overcommit. There are few sane options here. Since
1675 * alloc_buddy_huge_page() is checking the global counter,
1676 * though, we'll note that we're not allowed to exceed surplus
1677 * and won't grow the pool anywhere else. Not until one of the
1678 * sysctls are changed, or the surplus pages go out of use.
1680 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1681 min_count = max(count, min_count);
1682 try_to_free_low(h, min_count, nodes_allowed);
1683 while (min_count < persistent_huge_pages(h)) {
1684 if (!free_pool_huge_page(h, nodes_allowed, 0))
1686 cond_resched_lock(&hugetlb_lock);
1688 while (count < persistent_huge_pages(h)) {
1689 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1693 ret = persistent_huge_pages(h);
1694 spin_unlock(&hugetlb_lock);
1698 #define HSTATE_ATTR_RO(_name) \
1699 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1701 #define HSTATE_ATTR(_name) \
1702 static struct kobj_attribute _name##_attr = \
1703 __ATTR(_name, 0644, _name##_show, _name##_store)
1705 static struct kobject *hugepages_kobj;
1706 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1708 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1710 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1714 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1715 if (hstate_kobjs[i] == kobj) {
1717 *nidp = NUMA_NO_NODE;
1721 return kobj_to_node_hstate(kobj, nidp);
1724 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1725 struct kobj_attribute *attr, char *buf)
1728 unsigned long nr_huge_pages;
1731 h = kobj_to_hstate(kobj, &nid);
1732 if (nid == NUMA_NO_NODE)
1733 nr_huge_pages = h->nr_huge_pages;
1735 nr_huge_pages = h->nr_huge_pages_node[nid];
1737 return sprintf(buf, "%lu\n", nr_huge_pages);
1740 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
1741 struct hstate *h, int nid,
1742 unsigned long count, size_t len)
1745 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1747 if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
1752 if (nid == NUMA_NO_NODE) {
1754 * global hstate attribute
1756 if (!(obey_mempolicy &&
1757 init_nodemask_of_mempolicy(nodes_allowed))) {
1758 NODEMASK_FREE(nodes_allowed);
1759 nodes_allowed = &node_states[N_MEMORY];
1761 } else if (nodes_allowed) {
1763 * per node hstate attribute: adjust count to global,
1764 * but restrict alloc/free to the specified node.
1766 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1767 init_nodemask_of_node(nodes_allowed, nid);
1769 nodes_allowed = &node_states[N_MEMORY];
1771 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1773 if (nodes_allowed != &node_states[N_MEMORY])
1774 NODEMASK_FREE(nodes_allowed);
1778 NODEMASK_FREE(nodes_allowed);
1782 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1783 struct kobject *kobj, const char *buf,
1787 unsigned long count;
1791 err = kstrtoul(buf, 10, &count);
1795 h = kobj_to_hstate(kobj, &nid);
1796 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
1799 static ssize_t nr_hugepages_show(struct kobject *kobj,
1800 struct kobj_attribute *attr, char *buf)
1802 return nr_hugepages_show_common(kobj, attr, buf);
1805 static ssize_t nr_hugepages_store(struct kobject *kobj,
1806 struct kobj_attribute *attr, const char *buf, size_t len)
1808 return nr_hugepages_store_common(false, kobj, buf, len);
1810 HSTATE_ATTR(nr_hugepages);
1815 * hstate attribute for optionally mempolicy-based constraint on persistent
1816 * huge page alloc/free.
1818 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1819 struct kobj_attribute *attr, char *buf)
1821 return nr_hugepages_show_common(kobj, attr, buf);
1824 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1825 struct kobj_attribute *attr, const char *buf, size_t len)
1827 return nr_hugepages_store_common(true, kobj, buf, len);
1829 HSTATE_ATTR(nr_hugepages_mempolicy);
1833 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1834 struct kobj_attribute *attr, char *buf)
1836 struct hstate *h = kobj_to_hstate(kobj, NULL);
1837 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1840 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1841 struct kobj_attribute *attr, const char *buf, size_t count)
1844 unsigned long input;
1845 struct hstate *h = kobj_to_hstate(kobj, NULL);
1847 if (hstate_is_gigantic(h))
1850 err = kstrtoul(buf, 10, &input);
1854 spin_lock(&hugetlb_lock);
1855 h->nr_overcommit_huge_pages = input;
1856 spin_unlock(&hugetlb_lock);
1860 HSTATE_ATTR(nr_overcommit_hugepages);
1862 static ssize_t free_hugepages_show(struct kobject *kobj,
1863 struct kobj_attribute *attr, char *buf)
1866 unsigned long free_huge_pages;
1869 h = kobj_to_hstate(kobj, &nid);
1870 if (nid == NUMA_NO_NODE)
1871 free_huge_pages = h->free_huge_pages;
1873 free_huge_pages = h->free_huge_pages_node[nid];
1875 return sprintf(buf, "%lu\n", free_huge_pages);
1877 HSTATE_ATTR_RO(free_hugepages);
1879 static ssize_t resv_hugepages_show(struct kobject *kobj,
1880 struct kobj_attribute *attr, char *buf)
1882 struct hstate *h = kobj_to_hstate(kobj, NULL);
1883 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1885 HSTATE_ATTR_RO(resv_hugepages);
1887 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1888 struct kobj_attribute *attr, char *buf)
1891 unsigned long surplus_huge_pages;
1894 h = kobj_to_hstate(kobj, &nid);
1895 if (nid == NUMA_NO_NODE)
1896 surplus_huge_pages = h->surplus_huge_pages;
1898 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1900 return sprintf(buf, "%lu\n", surplus_huge_pages);
1902 HSTATE_ATTR_RO(surplus_hugepages);
1904 static struct attribute *hstate_attrs[] = {
1905 &nr_hugepages_attr.attr,
1906 &nr_overcommit_hugepages_attr.attr,
1907 &free_hugepages_attr.attr,
1908 &resv_hugepages_attr.attr,
1909 &surplus_hugepages_attr.attr,
1911 &nr_hugepages_mempolicy_attr.attr,
1916 static struct attribute_group hstate_attr_group = {
1917 .attrs = hstate_attrs,
1920 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1921 struct kobject **hstate_kobjs,
1922 struct attribute_group *hstate_attr_group)
1925 int hi = hstate_index(h);
1927 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1928 if (!hstate_kobjs[hi])
1931 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1933 kobject_put(hstate_kobjs[hi]);
1938 static void __init hugetlb_sysfs_init(void)
1943 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1944 if (!hugepages_kobj)
1947 for_each_hstate(h) {
1948 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1949 hstate_kobjs, &hstate_attr_group);
1951 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1958 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1959 * with node devices in node_devices[] using a parallel array. The array
1960 * index of a node device or _hstate == node id.
1961 * This is here to avoid any static dependency of the node device driver, in
1962 * the base kernel, on the hugetlb module.
1964 struct node_hstate {
1965 struct kobject *hugepages_kobj;
1966 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1968 struct node_hstate node_hstates[MAX_NUMNODES];
1971 * A subset of global hstate attributes for node devices
1973 static struct attribute *per_node_hstate_attrs[] = {
1974 &nr_hugepages_attr.attr,
1975 &free_hugepages_attr.attr,
1976 &surplus_hugepages_attr.attr,
1980 static struct attribute_group per_node_hstate_attr_group = {
1981 .attrs = per_node_hstate_attrs,
1985 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1986 * Returns node id via non-NULL nidp.
1988 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1992 for (nid = 0; nid < nr_node_ids; nid++) {
1993 struct node_hstate *nhs = &node_hstates[nid];
1995 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1996 if (nhs->hstate_kobjs[i] == kobj) {
2008 * Unregister hstate attributes from a single node device.
2009 * No-op if no hstate attributes attached.
2011 static void hugetlb_unregister_node(struct node *node)
2014 struct node_hstate *nhs = &node_hstates[node->dev.id];
2016 if (!nhs->hugepages_kobj)
2017 return; /* no hstate attributes */
2019 for_each_hstate(h) {
2020 int idx = hstate_index(h);
2021 if (nhs->hstate_kobjs[idx]) {
2022 kobject_put(nhs->hstate_kobjs[idx]);
2023 nhs->hstate_kobjs[idx] = NULL;
2027 kobject_put(nhs->hugepages_kobj);
2028 nhs->hugepages_kobj = NULL;
2032 * hugetlb module exit: unregister hstate attributes from node devices
2035 static void hugetlb_unregister_all_nodes(void)
2040 * disable node device registrations.
2042 register_hugetlbfs_with_node(NULL, NULL);
2045 * remove hstate attributes from any nodes that have them.
2047 for (nid = 0; nid < nr_node_ids; nid++)
2048 hugetlb_unregister_node(node_devices[nid]);
2052 * Register hstate attributes for a single node device.
2053 * No-op if attributes already registered.
2055 static void hugetlb_register_node(struct node *node)
2058 struct node_hstate *nhs = &node_hstates[node->dev.id];
2061 if (nhs->hugepages_kobj)
2062 return; /* already allocated */
2064 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2066 if (!nhs->hugepages_kobj)
2069 for_each_hstate(h) {
2070 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
2072 &per_node_hstate_attr_group);
2074 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2075 h->name, node->dev.id);
2076 hugetlb_unregister_node(node);
2083 * hugetlb init time: register hstate attributes for all registered node
2084 * devices of nodes that have memory. All on-line nodes should have
2085 * registered their associated device by this time.
2087 static void __init hugetlb_register_all_nodes(void)
2091 for_each_node_state(nid, N_MEMORY) {
2092 struct node *node = node_devices[nid];
2093 if (node->dev.id == nid)
2094 hugetlb_register_node(node);
2098 * Let the node device driver know we're here so it can
2099 * [un]register hstate attributes on node hotplug.
2101 register_hugetlbfs_with_node(hugetlb_register_node,
2102 hugetlb_unregister_node);
2104 #else /* !CONFIG_NUMA */
2106 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2114 static void hugetlb_unregister_all_nodes(void) { }
2116 static void hugetlb_register_all_nodes(void) { }
2120 static void __exit hugetlb_exit(void)
2124 hugetlb_unregister_all_nodes();
2126 for_each_hstate(h) {
2127 kobject_put(hstate_kobjs[hstate_index(h)]);
2130 kobject_put(hugepages_kobj);
2131 kfree(htlb_fault_mutex_table);
2133 module_exit(hugetlb_exit);
2135 static int __init hugetlb_init(void)
2139 if (!hugepages_supported())
2142 if (!size_to_hstate(default_hstate_size)) {
2143 default_hstate_size = HPAGE_SIZE;
2144 if (!size_to_hstate(default_hstate_size))
2145 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2147 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2148 if (default_hstate_max_huge_pages)
2149 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2151 hugetlb_init_hstates();
2152 gather_bootmem_prealloc();
2155 hugetlb_sysfs_init();
2156 hugetlb_register_all_nodes();
2157 hugetlb_cgroup_file_init();
2160 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2162 num_fault_mutexes = 1;
2164 htlb_fault_mutex_table =
2165 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2166 BUG_ON(!htlb_fault_mutex_table);
2168 for (i = 0; i < num_fault_mutexes; i++)
2169 mutex_init(&htlb_fault_mutex_table[i]);
2172 module_init(hugetlb_init);
2174 /* Should be called on processing a hugepagesz=... option */
2175 void __init hugetlb_add_hstate(unsigned order)
2180 if (size_to_hstate(PAGE_SIZE << order)) {
2181 pr_warning("hugepagesz= specified twice, ignoring\n");
2184 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2186 h = &hstates[hugetlb_max_hstate++];
2188 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2189 h->nr_huge_pages = 0;
2190 h->free_huge_pages = 0;
2191 for (i = 0; i < MAX_NUMNODES; ++i)
2192 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2193 INIT_LIST_HEAD(&h->hugepage_activelist);
2194 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2195 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2196 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2197 huge_page_size(h)/1024);
2202 static int __init hugetlb_nrpages_setup(char *s)
2205 static unsigned long *last_mhp;
2208 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2209 * so this hugepages= parameter goes to the "default hstate".
2211 if (!hugetlb_max_hstate)
2212 mhp = &default_hstate_max_huge_pages;
2214 mhp = &parsed_hstate->max_huge_pages;
2216 if (mhp == last_mhp) {
2217 pr_warning("hugepages= specified twice without "
2218 "interleaving hugepagesz=, ignoring\n");
2222 if (sscanf(s, "%lu", mhp) <= 0)
2226 * Global state is always initialized later in hugetlb_init.
2227 * But we need to allocate >= MAX_ORDER hstates here early to still
2228 * use the bootmem allocator.
2230 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2231 hugetlb_hstate_alloc_pages(parsed_hstate);
2237 __setup("hugepages=", hugetlb_nrpages_setup);
2239 static int __init hugetlb_default_setup(char *s)
2241 default_hstate_size = memparse(s, &s);
2244 __setup("default_hugepagesz=", hugetlb_default_setup);
2246 static unsigned int cpuset_mems_nr(unsigned int *array)
2249 unsigned int nr = 0;
2251 for_each_node_mask(node, cpuset_current_mems_allowed)
2257 #ifdef CONFIG_SYSCTL
2258 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2259 struct ctl_table *table, int write,
2260 void __user *buffer, size_t *length, loff_t *ppos)
2262 struct hstate *h = &default_hstate;
2263 unsigned long tmp = h->max_huge_pages;
2266 if (!hugepages_supported())
2270 table->maxlen = sizeof(unsigned long);
2271 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2276 ret = __nr_hugepages_store_common(obey_mempolicy, h,
2277 NUMA_NO_NODE, tmp, *length);
2282 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2283 void __user *buffer, size_t *length, loff_t *ppos)
2286 return hugetlb_sysctl_handler_common(false, table, write,
2287 buffer, length, ppos);
2291 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2292 void __user *buffer, size_t *length, loff_t *ppos)
2294 return hugetlb_sysctl_handler_common(true, table, write,
2295 buffer, length, ppos);
2297 #endif /* CONFIG_NUMA */
2299 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2300 void __user *buffer,
2301 size_t *length, loff_t *ppos)
2303 struct hstate *h = &default_hstate;
2307 if (!hugepages_supported())
2310 tmp = h->nr_overcommit_huge_pages;
2312 if (write && hstate_is_gigantic(h))
2316 table->maxlen = sizeof(unsigned long);
2317 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2322 spin_lock(&hugetlb_lock);
2323 h->nr_overcommit_huge_pages = tmp;
2324 spin_unlock(&hugetlb_lock);
2330 #endif /* CONFIG_SYSCTL */
2332 void hugetlb_report_meminfo(struct seq_file *m)
2334 struct hstate *h = &default_hstate;
2335 if (!hugepages_supported())
2338 "HugePages_Total: %5lu\n"
2339 "HugePages_Free: %5lu\n"
2340 "HugePages_Rsvd: %5lu\n"
2341 "HugePages_Surp: %5lu\n"
2342 "Hugepagesize: %8lu kB\n",
2346 h->surplus_huge_pages,
2347 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2350 int hugetlb_report_node_meminfo(int nid, char *buf)
2352 struct hstate *h = &default_hstate;
2353 if (!hugepages_supported())
2356 "Node %d HugePages_Total: %5u\n"
2357 "Node %d HugePages_Free: %5u\n"
2358 "Node %d HugePages_Surp: %5u\n",
2359 nid, h->nr_huge_pages_node[nid],
2360 nid, h->free_huge_pages_node[nid],
2361 nid, h->surplus_huge_pages_node[nid]);
2364 void hugetlb_show_meminfo(void)
2369 if (!hugepages_supported())
2372 for_each_node_state(nid, N_MEMORY)
2374 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2376 h->nr_huge_pages_node[nid],
2377 h->free_huge_pages_node[nid],
2378 h->surplus_huge_pages_node[nid],
2379 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2382 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2383 unsigned long hugetlb_total_pages(void)
2386 unsigned long nr_total_pages = 0;
2389 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2390 return nr_total_pages;
2393 static int hugetlb_acct_memory(struct hstate *h, long delta)
2397 spin_lock(&hugetlb_lock);
2399 * When cpuset is configured, it breaks the strict hugetlb page
2400 * reservation as the accounting is done on a global variable. Such
2401 * reservation is completely rubbish in the presence of cpuset because
2402 * the reservation is not checked against page availability for the
2403 * current cpuset. Application can still potentially OOM'ed by kernel
2404 * with lack of free htlb page in cpuset that the task is in.
2405 * Attempt to enforce strict accounting with cpuset is almost
2406 * impossible (or too ugly) because cpuset is too fluid that
2407 * task or memory node can be dynamically moved between cpusets.
2409 * The change of semantics for shared hugetlb mapping with cpuset is
2410 * undesirable. However, in order to preserve some of the semantics,
2411 * we fall back to check against current free page availability as
2412 * a best attempt and hopefully to minimize the impact of changing
2413 * semantics that cpuset has.
2416 if (gather_surplus_pages(h, delta) < 0)
2419 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2420 return_unused_surplus_pages(h, delta);
2427 return_unused_surplus_pages(h, (unsigned long) -delta);
2430 spin_unlock(&hugetlb_lock);
2434 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2436 struct resv_map *resv = vma_resv_map(vma);
2439 * This new VMA should share its siblings reservation map if present.
2440 * The VMA will only ever have a valid reservation map pointer where
2441 * it is being copied for another still existing VMA. As that VMA
2442 * has a reference to the reservation map it cannot disappear until
2443 * after this open call completes. It is therefore safe to take a
2444 * new reference here without additional locking.
2446 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2447 kref_get(&resv->refs);
2450 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2452 struct hstate *h = hstate_vma(vma);
2453 struct resv_map *resv = vma_resv_map(vma);
2454 struct hugepage_subpool *spool = subpool_vma(vma);
2455 unsigned long reserve, start, end;
2457 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2460 start = vma_hugecache_offset(h, vma, vma->vm_start);
2461 end = vma_hugecache_offset(h, vma, vma->vm_end);
2463 reserve = (end - start) - region_count(resv, start, end);
2465 kref_put(&resv->refs, resv_map_release);
2468 hugetlb_acct_memory(h, -reserve);
2469 hugepage_subpool_put_pages(spool, reserve);
2474 * We cannot handle pagefaults against hugetlb pages at all. They cause
2475 * handle_mm_fault() to try to instantiate regular-sized pages in the
2476 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2479 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2485 const struct vm_operations_struct hugetlb_vm_ops = {
2486 .fault = hugetlb_vm_op_fault,
2487 .open = hugetlb_vm_op_open,
2488 .close = hugetlb_vm_op_close,
2491 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2497 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2498 vma->vm_page_prot)));
2500 entry = huge_pte_wrprotect(mk_huge_pte(page,
2501 vma->vm_page_prot));
2503 entry = pte_mkyoung(entry);
2504 entry = pte_mkhuge(entry);
2505 entry = arch_make_huge_pte(entry, vma, page, writable);
2510 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2511 unsigned long address, pte_t *ptep)
2515 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2516 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2517 update_mmu_cache(vma, address, ptep);
2520 static int is_hugetlb_entry_migration(pte_t pte)
2524 if (huge_pte_none(pte) || pte_present(pte))
2526 swp = pte_to_swp_entry(pte);
2527 if (non_swap_entry(swp) && is_migration_entry(swp))
2533 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2537 if (huge_pte_none(pte) || pte_present(pte))
2539 swp = pte_to_swp_entry(pte);
2540 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2546 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2547 struct vm_area_struct *vma)
2549 pte_t *src_pte, *dst_pte, entry;
2550 struct page *ptepage;
2553 struct hstate *h = hstate_vma(vma);
2554 unsigned long sz = huge_page_size(h);
2555 unsigned long mmun_start; /* For mmu_notifiers */
2556 unsigned long mmun_end; /* For mmu_notifiers */
2559 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2561 mmun_start = vma->vm_start;
2562 mmun_end = vma->vm_end;
2564 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
2566 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2567 spinlock_t *src_ptl, *dst_ptl;
2568 src_pte = huge_pte_offset(src, addr);
2571 dst_pte = huge_pte_alloc(dst, addr, sz);
2577 /* If the pagetables are shared don't copy or take references */
2578 if (dst_pte == src_pte)
2581 dst_ptl = huge_pte_lock(h, dst, dst_pte);
2582 src_ptl = huge_pte_lockptr(h, src, src_pte);
2583 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2584 entry = huge_ptep_get(src_pte);
2585 if (huge_pte_none(entry)) { /* skip none entry */
2587 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
2588 is_hugetlb_entry_hwpoisoned(entry))) {
2589 swp_entry_t swp_entry = pte_to_swp_entry(entry);
2591 if (is_write_migration_entry(swp_entry) && cow) {
2593 * COW mappings require pages in both
2594 * parent and child to be set to read.
2596 make_migration_entry_read(&swp_entry);
2597 entry = swp_entry_to_pte(swp_entry);
2598 set_huge_pte_at(src, addr, src_pte, entry);
2600 set_huge_pte_at(dst, addr, dst_pte, entry);
2603 huge_ptep_set_wrprotect(src, addr, src_pte);
2604 mmu_notifier_invalidate_range(src, mmun_start,
2607 entry = huge_ptep_get(src_pte);
2608 ptepage = pte_page(entry);
2610 page_dup_rmap(ptepage);
2611 set_huge_pte_at(dst, addr, dst_pte, entry);
2613 spin_unlock(src_ptl);
2614 spin_unlock(dst_ptl);
2618 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
2623 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2624 unsigned long start, unsigned long end,
2625 struct page *ref_page)
2627 int force_flush = 0;
2628 struct mm_struct *mm = vma->vm_mm;
2629 unsigned long address;
2634 struct hstate *h = hstate_vma(vma);
2635 unsigned long sz = huge_page_size(h);
2636 const unsigned long mmun_start = start; /* For mmu_notifiers */
2637 const unsigned long mmun_end = end; /* For mmu_notifiers */
2639 WARN_ON(!is_vm_hugetlb_page(vma));
2640 BUG_ON(start & ~huge_page_mask(h));
2641 BUG_ON(end & ~huge_page_mask(h));
2643 tlb_start_vma(tlb, vma);
2644 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2647 for (; address < end; address += sz) {
2648 ptep = huge_pte_offset(mm, address);
2652 ptl = huge_pte_lock(h, mm, ptep);
2653 if (huge_pmd_unshare(mm, &address, ptep))
2656 pte = huge_ptep_get(ptep);
2657 if (huge_pte_none(pte))
2661 * Migrating hugepage or HWPoisoned hugepage is already
2662 * unmapped and its refcount is dropped, so just clear pte here.
2664 if (unlikely(!pte_present(pte))) {
2665 huge_pte_clear(mm, address, ptep);
2669 page = pte_page(pte);
2671 * If a reference page is supplied, it is because a specific
2672 * page is being unmapped, not a range. Ensure the page we
2673 * are about to unmap is the actual page of interest.
2676 if (page != ref_page)
2680 * Mark the VMA as having unmapped its page so that
2681 * future faults in this VMA will fail rather than
2682 * looking like data was lost
2684 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2687 pte = huge_ptep_get_and_clear(mm, address, ptep);
2688 tlb_remove_tlb_entry(tlb, ptep, address);
2689 if (huge_pte_dirty(pte))
2690 set_page_dirty(page);
2692 page_remove_rmap(page);
2693 force_flush = !__tlb_remove_page(tlb, page);
2699 /* Bail out after unmapping reference page if supplied */
2708 * mmu_gather ran out of room to batch pages, we break out of
2709 * the PTE lock to avoid doing the potential expensive TLB invalidate
2710 * and page-free while holding it.
2715 if (address < end && !ref_page)
2718 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2719 tlb_end_vma(tlb, vma);
2722 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2723 struct vm_area_struct *vma, unsigned long start,
2724 unsigned long end, struct page *ref_page)
2726 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2729 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2730 * test will fail on a vma being torn down, and not grab a page table
2731 * on its way out. We're lucky that the flag has such an appropriate
2732 * name, and can in fact be safely cleared here. We could clear it
2733 * before the __unmap_hugepage_range above, but all that's necessary
2734 * is to clear it before releasing the i_mmap_rwsem. This works
2735 * because in the context this is called, the VMA is about to be
2736 * destroyed and the i_mmap_rwsem is held.
2738 vma->vm_flags &= ~VM_MAYSHARE;
2741 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2742 unsigned long end, struct page *ref_page)
2744 struct mm_struct *mm;
2745 struct mmu_gather tlb;
2749 tlb_gather_mmu(&tlb, mm, start, end);
2750 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2751 tlb_finish_mmu(&tlb, start, end);
2755 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2756 * mappping it owns the reserve page for. The intention is to unmap the page
2757 * from other VMAs and let the children be SIGKILLed if they are faulting the
2760 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2761 struct page *page, unsigned long address)
2763 struct hstate *h = hstate_vma(vma);
2764 struct vm_area_struct *iter_vma;
2765 struct address_space *mapping;
2769 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2770 * from page cache lookup which is in HPAGE_SIZE units.
2772 address = address & huge_page_mask(h);
2773 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2775 mapping = file_inode(vma->vm_file)->i_mapping;
2778 * Take the mapping lock for the duration of the table walk. As
2779 * this mapping should be shared between all the VMAs,
2780 * __unmap_hugepage_range() is called as the lock is already held
2782 i_mmap_lock_write(mapping);
2783 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2784 /* Do not unmap the current VMA */
2785 if (iter_vma == vma)
2789 * Unmap the page from other VMAs without their own reserves.
2790 * They get marked to be SIGKILLed if they fault in these
2791 * areas. This is because a future no-page fault on this VMA
2792 * could insert a zeroed page instead of the data existing
2793 * from the time of fork. This would look like data corruption
2795 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2796 unmap_hugepage_range(iter_vma, address,
2797 address + huge_page_size(h), page);
2799 i_mmap_unlock_write(mapping);
2803 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2804 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2805 * cannot race with other handlers or page migration.
2806 * Keep the pte_same checks anyway to make transition from the mutex easier.
2808 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2809 unsigned long address, pte_t *ptep, pte_t pte,
2810 struct page *pagecache_page, spinlock_t *ptl)
2812 struct hstate *h = hstate_vma(vma);
2813 struct page *old_page, *new_page;
2814 int ret = 0, outside_reserve = 0;
2815 unsigned long mmun_start; /* For mmu_notifiers */
2816 unsigned long mmun_end; /* For mmu_notifiers */
2818 old_page = pte_page(pte);
2821 /* If no-one else is actually using this page, avoid the copy
2822 * and just make the page writable */
2823 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2824 page_move_anon_rmap(old_page, vma, address);
2825 set_huge_ptep_writable(vma, address, ptep);
2830 * If the process that created a MAP_PRIVATE mapping is about to
2831 * perform a COW due to a shared page count, attempt to satisfy
2832 * the allocation without using the existing reserves. The pagecache
2833 * page is used to determine if the reserve at this address was
2834 * consumed or not. If reserves were used, a partial faulted mapping
2835 * at the time of fork() could consume its reserves on COW instead
2836 * of the full address range.
2838 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2839 old_page != pagecache_page)
2840 outside_reserve = 1;
2842 page_cache_get(old_page);
2845 * Drop page table lock as buddy allocator may be called. It will
2846 * be acquired again before returning to the caller, as expected.
2849 new_page = alloc_huge_page(vma, address, outside_reserve);
2851 if (IS_ERR(new_page)) {
2853 * If a process owning a MAP_PRIVATE mapping fails to COW,
2854 * it is due to references held by a child and an insufficient
2855 * huge page pool. To guarantee the original mappers
2856 * reliability, unmap the page from child processes. The child
2857 * may get SIGKILLed if it later faults.
2859 if (outside_reserve) {
2860 page_cache_release(old_page);
2861 BUG_ON(huge_pte_none(pte));
2862 unmap_ref_private(mm, vma, old_page, address);
2863 BUG_ON(huge_pte_none(pte));
2865 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2867 pte_same(huge_ptep_get(ptep), pte)))
2868 goto retry_avoidcopy;
2870 * race occurs while re-acquiring page table
2871 * lock, and our job is done.
2876 ret = (PTR_ERR(new_page) == -ENOMEM) ?
2877 VM_FAULT_OOM : VM_FAULT_SIGBUS;
2878 goto out_release_old;
2882 * When the original hugepage is shared one, it does not have
2883 * anon_vma prepared.
2885 if (unlikely(anon_vma_prepare(vma))) {
2887 goto out_release_all;
2890 copy_user_huge_page(new_page, old_page, address, vma,
2891 pages_per_huge_page(h));
2892 __SetPageUptodate(new_page);
2894 mmun_start = address & huge_page_mask(h);
2895 mmun_end = mmun_start + huge_page_size(h);
2896 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2899 * Retake the page table lock to check for racing updates
2900 * before the page tables are altered
2903 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2904 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
2905 ClearPagePrivate(new_page);
2908 huge_ptep_clear_flush(vma, address, ptep);
2909 mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
2910 set_huge_pte_at(mm, address, ptep,
2911 make_huge_pte(vma, new_page, 1));
2912 page_remove_rmap(old_page);
2913 hugepage_add_new_anon_rmap(new_page, vma, address);
2914 /* Make the old page be freed below */
2915 new_page = old_page;
2918 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2920 page_cache_release(new_page);
2922 page_cache_release(old_page);
2924 spin_lock(ptl); /* Caller expects lock to be held */
2928 /* Return the pagecache page at a given address within a VMA */
2929 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2930 struct vm_area_struct *vma, unsigned long address)
2932 struct address_space *mapping;
2935 mapping = vma->vm_file->f_mapping;
2936 idx = vma_hugecache_offset(h, vma, address);
2938 return find_lock_page(mapping, idx);
2942 * Return whether there is a pagecache page to back given address within VMA.
2943 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2945 static bool hugetlbfs_pagecache_present(struct hstate *h,
2946 struct vm_area_struct *vma, unsigned long address)
2948 struct address_space *mapping;
2952 mapping = vma->vm_file->f_mapping;
2953 idx = vma_hugecache_offset(h, vma, address);
2955 page = find_get_page(mapping, idx);
2958 return page != NULL;
2961 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2962 struct address_space *mapping, pgoff_t idx,
2963 unsigned long address, pte_t *ptep, unsigned int flags)
2965 struct hstate *h = hstate_vma(vma);
2966 int ret = VM_FAULT_SIGBUS;
2974 * Currently, we are forced to kill the process in the event the
2975 * original mapper has unmapped pages from the child due to a failed
2976 * COW. Warn that such a situation has occurred as it may not be obvious
2978 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2979 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2985 * Use page lock to guard against racing truncation
2986 * before we get page_table_lock.
2989 page = find_lock_page(mapping, idx);
2991 size = i_size_read(mapping->host) >> huge_page_shift(h);
2994 page = alloc_huge_page(vma, address, 0);
2996 ret = PTR_ERR(page);
3000 ret = VM_FAULT_SIGBUS;
3003 clear_huge_page(page, address, pages_per_huge_page(h));
3004 __SetPageUptodate(page);
3006 if (vma->vm_flags & VM_MAYSHARE) {
3008 struct inode *inode = mapping->host;
3010 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
3017 ClearPagePrivate(page);
3019 spin_lock(&inode->i_lock);
3020 inode->i_blocks += blocks_per_huge_page(h);
3021 spin_unlock(&inode->i_lock);
3024 if (unlikely(anon_vma_prepare(vma))) {
3026 goto backout_unlocked;
3032 * If memory error occurs between mmap() and fault, some process
3033 * don't have hwpoisoned swap entry for errored virtual address.
3034 * So we need to block hugepage fault by PG_hwpoison bit check.
3036 if (unlikely(PageHWPoison(page))) {
3037 ret = VM_FAULT_HWPOISON |
3038 VM_FAULT_SET_HINDEX(hstate_index(h));
3039 goto backout_unlocked;
3044 * If we are going to COW a private mapping later, we examine the
3045 * pending reservations for this page now. This will ensure that
3046 * any allocations necessary to record that reservation occur outside
3049 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
3050 if (vma_needs_reservation(h, vma, address) < 0) {
3052 goto backout_unlocked;
3055 ptl = huge_pte_lockptr(h, mm, ptep);
3057 size = i_size_read(mapping->host) >> huge_page_shift(h);
3062 if (!huge_pte_none(huge_ptep_get(ptep)))
3066 ClearPagePrivate(page);
3067 hugepage_add_new_anon_rmap(page, vma, address);
3069 page_dup_rmap(page);
3070 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
3071 && (vma->vm_flags & VM_SHARED)));
3072 set_huge_pte_at(mm, address, ptep, new_pte);
3074 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3075 /* Optimization, do the COW without a second fault */
3076 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
3093 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3094 struct vm_area_struct *vma,
3095 struct address_space *mapping,
3096 pgoff_t idx, unsigned long address)
3098 unsigned long key[2];
3101 if (vma->vm_flags & VM_SHARED) {
3102 key[0] = (unsigned long) mapping;
3105 key[0] = (unsigned long) mm;
3106 key[1] = address >> huge_page_shift(h);
3109 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
3111 return hash & (num_fault_mutexes - 1);
3115 * For uniprocesor systems we always use a single mutex, so just
3116 * return 0 and avoid the hashing overhead.
3118 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3119 struct vm_area_struct *vma,
3120 struct address_space *mapping,
3121 pgoff_t idx, unsigned long address)
3127 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3128 unsigned long address, unsigned int flags)
3135 struct page *page = NULL;
3136 struct page *pagecache_page = NULL;
3137 struct hstate *h = hstate_vma(vma);
3138 struct address_space *mapping;
3139 int need_wait_lock = 0;
3141 address &= huge_page_mask(h);
3143 ptep = huge_pte_offset(mm, address);
3145 entry = huge_ptep_get(ptep);
3146 if (unlikely(is_hugetlb_entry_migration(entry))) {
3147 migration_entry_wait_huge(vma, mm, ptep);
3149 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3150 return VM_FAULT_HWPOISON_LARGE |
3151 VM_FAULT_SET_HINDEX(hstate_index(h));
3154 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
3156 return VM_FAULT_OOM;
3158 mapping = vma->vm_file->f_mapping;
3159 idx = vma_hugecache_offset(h, vma, address);
3162 * Serialize hugepage allocation and instantiation, so that we don't
3163 * get spurious allocation failures if two CPUs race to instantiate
3164 * the same page in the page cache.
3166 hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
3167 mutex_lock(&htlb_fault_mutex_table[hash]);
3169 entry = huge_ptep_get(ptep);
3170 if (huge_pte_none(entry)) {
3171 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3178 * entry could be a migration/hwpoison entry at this point, so this
3179 * check prevents the kernel from going below assuming that we have
3180 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3181 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3184 if (!pte_present(entry))
3188 * If we are going to COW the mapping later, we examine the pending
3189 * reservations for this page now. This will ensure that any
3190 * allocations necessary to record that reservation occur outside the
3191 * spinlock. For private mappings, we also lookup the pagecache
3192 * page now as it is used to determine if a reservation has been
3195 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3196 if (vma_needs_reservation(h, vma, address) < 0) {
3201 if (!(vma->vm_flags & VM_MAYSHARE))
3202 pagecache_page = hugetlbfs_pagecache_page(h,
3206 ptl = huge_pte_lock(h, mm, ptep);
3208 /* Check for a racing update before calling hugetlb_cow */
3209 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3213 * hugetlb_cow() requires page locks of pte_page(entry) and
3214 * pagecache_page, so here we need take the former one
3215 * when page != pagecache_page or !pagecache_page.
3217 page = pte_page(entry);
3218 if (page != pagecache_page)
3219 if (!trylock_page(page)) {
3226 if (flags & FAULT_FLAG_WRITE) {
3227 if (!huge_pte_write(entry)) {
3228 ret = hugetlb_cow(mm, vma, address, ptep, entry,
3229 pagecache_page, ptl);
3232 entry = huge_pte_mkdirty(entry);
3234 entry = pte_mkyoung(entry);
3235 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3236 flags & FAULT_FLAG_WRITE))
3237 update_mmu_cache(vma, address, ptep);
3239 if (page != pagecache_page)
3245 if (pagecache_page) {
3246 unlock_page(pagecache_page);
3247 put_page(pagecache_page);
3250 mutex_unlock(&htlb_fault_mutex_table[hash]);
3252 * Generally it's safe to hold refcount during waiting page lock. But
3253 * here we just wait to defer the next page fault to avoid busy loop and
3254 * the page is not used after unlocked before returning from the current
3255 * page fault. So we are safe from accessing freed page, even if we wait
3256 * here without taking refcount.
3259 wait_on_page_locked(page);
3263 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3264 struct page **pages, struct vm_area_struct **vmas,
3265 unsigned long *position, unsigned long *nr_pages,
3266 long i, unsigned int flags)
3268 unsigned long pfn_offset;
3269 unsigned long vaddr = *position;
3270 unsigned long remainder = *nr_pages;
3271 struct hstate *h = hstate_vma(vma);
3273 while (vaddr < vma->vm_end && remainder) {
3275 spinlock_t *ptl = NULL;
3280 * If we have a pending SIGKILL, don't keep faulting pages and
3281 * potentially allocating memory.
3283 if (unlikely(fatal_signal_pending(current))) {
3289 * Some archs (sparc64, sh*) have multiple pte_ts to
3290 * each hugepage. We have to make sure we get the
3291 * first, for the page indexing below to work.
3293 * Note that page table lock is not held when pte is null.
3295 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3297 ptl = huge_pte_lock(h, mm, pte);
3298 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3301 * When coredumping, it suits get_dump_page if we just return
3302 * an error where there's an empty slot with no huge pagecache
3303 * to back it. This way, we avoid allocating a hugepage, and
3304 * the sparse dumpfile avoids allocating disk blocks, but its
3305 * huge holes still show up with zeroes where they need to be.
3307 if (absent && (flags & FOLL_DUMP) &&
3308 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3316 * We need call hugetlb_fault for both hugepages under migration
3317 * (in which case hugetlb_fault waits for the migration,) and
3318 * hwpoisoned hugepages (in which case we need to prevent the
3319 * caller from accessing to them.) In order to do this, we use
3320 * here is_swap_pte instead of is_hugetlb_entry_migration and
3321 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3322 * both cases, and because we can't follow correct pages
3323 * directly from any kind of swap entries.
3325 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3326 ((flags & FOLL_WRITE) &&
3327 !huge_pte_write(huge_ptep_get(pte)))) {
3332 ret = hugetlb_fault(mm, vma, vaddr,
3333 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3334 if (!(ret & VM_FAULT_ERROR))
3341 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3342 page = pte_page(huge_ptep_get(pte));
3345 pages[i] = mem_map_offset(page, pfn_offset);
3346 get_page_foll(pages[i]);
3356 if (vaddr < vma->vm_end && remainder &&
3357 pfn_offset < pages_per_huge_page(h)) {
3359 * We use pfn_offset to avoid touching the pageframes
3360 * of this compound page.
3366 *nr_pages = remainder;
3369 return i ? i : -EFAULT;
3372 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3373 unsigned long address, unsigned long end, pgprot_t newprot)
3375 struct mm_struct *mm = vma->vm_mm;
3376 unsigned long start = address;
3379 struct hstate *h = hstate_vma(vma);
3380 unsigned long pages = 0;
3382 BUG_ON(address >= end);
3383 flush_cache_range(vma, address, end);
3385 mmu_notifier_invalidate_range_start(mm, start, end);
3386 i_mmap_lock_write(vma->vm_file->f_mapping);
3387 for (; address < end; address += huge_page_size(h)) {
3389 ptep = huge_pte_offset(mm, address);
3392 ptl = huge_pte_lock(h, mm, ptep);
3393 if (huge_pmd_unshare(mm, &address, ptep)) {
3398 pte = huge_ptep_get(ptep);
3399 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
3403 if (unlikely(is_hugetlb_entry_migration(pte))) {
3404 swp_entry_t entry = pte_to_swp_entry(pte);
3406 if (is_write_migration_entry(entry)) {
3409 make_migration_entry_read(&entry);
3410 newpte = swp_entry_to_pte(entry);
3411 set_huge_pte_at(mm, address, ptep, newpte);
3417 if (!huge_pte_none(pte)) {
3418 pte = huge_ptep_get_and_clear(mm, address, ptep);
3419 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3420 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3421 set_huge_pte_at(mm, address, ptep, pte);
3427 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
3428 * may have cleared our pud entry and done put_page on the page table:
3429 * once we release i_mmap_rwsem, another task can do the final put_page
3430 * and that page table be reused and filled with junk.
3432 flush_tlb_range(vma, start, end);
3433 mmu_notifier_invalidate_range(mm, start, end);
3434 i_mmap_unlock_write(vma->vm_file->f_mapping);
3435 mmu_notifier_invalidate_range_end(mm, start, end);
3437 return pages << h->order;
3440 int hugetlb_reserve_pages(struct inode *inode,
3442 struct vm_area_struct *vma,
3443 vm_flags_t vm_flags)
3446 struct hstate *h = hstate_inode(inode);
3447 struct hugepage_subpool *spool = subpool_inode(inode);
3448 struct resv_map *resv_map;
3451 * Only apply hugepage reservation if asked. At fault time, an
3452 * attempt will be made for VM_NORESERVE to allocate a page
3453 * without using reserves
3455 if (vm_flags & VM_NORESERVE)
3459 * Shared mappings base their reservation on the number of pages that
3460 * are already allocated on behalf of the file. Private mappings need
3461 * to reserve the full area even if read-only as mprotect() may be
3462 * called to make the mapping read-write. Assume !vma is a shm mapping
3464 if (!vma || vma->vm_flags & VM_MAYSHARE) {
3465 resv_map = inode_resv_map(inode);
3467 chg = region_chg(resv_map, from, to);
3470 resv_map = resv_map_alloc();
3476 set_vma_resv_map(vma, resv_map);
3477 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3485 /* There must be enough pages in the subpool for the mapping */
3486 if (hugepage_subpool_get_pages(spool, chg)) {
3492 * Check enough hugepages are available for the reservation.
3493 * Hand the pages back to the subpool if there are not
3495 ret = hugetlb_acct_memory(h, chg);
3497 hugepage_subpool_put_pages(spool, chg);
3502 * Account for the reservations made. Shared mappings record regions
3503 * that have reservations as they are shared by multiple VMAs.
3504 * When the last VMA disappears, the region map says how much
3505 * the reservation was and the page cache tells how much of
3506 * the reservation was consumed. Private mappings are per-VMA and
3507 * only the consumed reservations are tracked. When the VMA
3508 * disappears, the original reservation is the VMA size and the
3509 * consumed reservations are stored in the map. Hence, nothing
3510 * else has to be done for private mappings here
3512 if (!vma || vma->vm_flags & VM_MAYSHARE)
3513 region_add(resv_map, from, to);
3516 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3517 kref_put(&resv_map->refs, resv_map_release);
3521 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3523 struct hstate *h = hstate_inode(inode);
3524 struct resv_map *resv_map = inode_resv_map(inode);
3526 struct hugepage_subpool *spool = subpool_inode(inode);
3529 chg = region_truncate(resv_map, offset);
3530 spin_lock(&inode->i_lock);
3531 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3532 spin_unlock(&inode->i_lock);
3534 hugepage_subpool_put_pages(spool, (chg - freed));
3535 hugetlb_acct_memory(h, -(chg - freed));
3538 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3539 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3540 struct vm_area_struct *vma,
3541 unsigned long addr, pgoff_t idx)
3543 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3545 unsigned long sbase = saddr & PUD_MASK;
3546 unsigned long s_end = sbase + PUD_SIZE;
3548 /* Allow segments to share if only one is marked locked */
3549 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3550 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3553 * match the virtual addresses, permission and the alignment of the
3556 if (pmd_index(addr) != pmd_index(saddr) ||
3557 vm_flags != svm_flags ||
3558 sbase < svma->vm_start || svma->vm_end < s_end)
3564 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3566 unsigned long base = addr & PUD_MASK;
3567 unsigned long end = base + PUD_SIZE;
3570 * check on proper vm_flags and page table alignment
3572 if (vma->vm_flags & VM_MAYSHARE &&
3573 vma->vm_start <= base && end <= vma->vm_end)
3579 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3580 * and returns the corresponding pte. While this is not necessary for the
3581 * !shared pmd case because we can allocate the pmd later as well, it makes the
3582 * code much cleaner. pmd allocation is essential for the shared case because
3583 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
3584 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3585 * bad pmd for sharing.
3587 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3589 struct vm_area_struct *vma = find_vma(mm, addr);
3590 struct address_space *mapping = vma->vm_file->f_mapping;
3591 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3593 struct vm_area_struct *svma;
3594 unsigned long saddr;
3599 if (!vma_shareable(vma, addr))
3600 return (pte_t *)pmd_alloc(mm, pud, addr);
3602 i_mmap_lock_write(mapping);
3603 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3607 saddr = page_table_shareable(svma, vma, addr, idx);
3609 spte = huge_pte_offset(svma->vm_mm, saddr);
3612 get_page(virt_to_page(spte));
3621 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3623 if (pud_none(*pud)) {
3624 pud_populate(mm, pud,
3625 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3627 put_page(virt_to_page(spte));
3632 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3633 i_mmap_unlock_write(mapping);
3638 * unmap huge page backed by shared pte.
3640 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3641 * indicated by page_count > 1, unmap is achieved by clearing pud and
3642 * decrementing the ref count. If count == 1, the pte page is not shared.
3644 * called with page table lock held.
3646 * returns: 1 successfully unmapped a shared pte page
3647 * 0 the underlying pte page is not shared, or it is the last user
3649 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3651 pgd_t *pgd = pgd_offset(mm, *addr);
3652 pud_t *pud = pud_offset(pgd, *addr);
3654 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3655 if (page_count(virt_to_page(ptep)) == 1)
3659 put_page(virt_to_page(ptep));
3661 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3664 #define want_pmd_share() (1)
3665 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3666 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3670 #define want_pmd_share() (0)
3671 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3673 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3674 pte_t *huge_pte_alloc(struct mm_struct *mm,
3675 unsigned long addr, unsigned long sz)
3681 pgd = pgd_offset(mm, addr);
3682 pud = pud_alloc(mm, pgd, addr);
3684 if (sz == PUD_SIZE) {
3687 BUG_ON(sz != PMD_SIZE);
3688 if (want_pmd_share() && pud_none(*pud))
3689 pte = huge_pmd_share(mm, addr, pud);
3691 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3694 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3699 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3705 pgd = pgd_offset(mm, addr);
3706 if (pgd_present(*pgd)) {
3707 pud = pud_offset(pgd, addr);
3708 if (pud_present(*pud)) {
3710 return (pte_t *)pud;
3711 pmd = pmd_offset(pud, addr);
3714 return (pte_t *) pmd;
3717 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3720 * These functions are overwritable if your architecture needs its own
3723 struct page * __weak
3724 follow_huge_addr(struct mm_struct *mm, unsigned long address,
3727 return ERR_PTR(-EINVAL);
3730 struct page * __weak
3731 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3732 pmd_t *pmd, int flags)
3734 struct page *page = NULL;
3737 ptl = pmd_lockptr(mm, pmd);
3740 * make sure that the address range covered by this pmd is not
3741 * unmapped from other threads.
3743 if (!pmd_huge(*pmd))
3745 if (pmd_present(*pmd)) {
3746 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
3747 if (flags & FOLL_GET)
3750 if (is_hugetlb_entry_migration(huge_ptep_get((pte_t *)pmd))) {
3752 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
3756 * hwpoisoned entry is treated as no_page_table in
3757 * follow_page_mask().
3765 struct page * __weak
3766 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3767 pud_t *pud, int flags)
3769 if (flags & FOLL_GET)
3772 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
3775 #ifdef CONFIG_MEMORY_FAILURE
3777 /* Should be called in hugetlb_lock */
3778 static int is_hugepage_on_freelist(struct page *hpage)
3782 struct hstate *h = page_hstate(hpage);
3783 int nid = page_to_nid(hpage);
3785 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3792 * This function is called from memory failure code.
3793 * Assume the caller holds page lock of the head page.
3795 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3797 struct hstate *h = page_hstate(hpage);
3798 int nid = page_to_nid(hpage);
3801 spin_lock(&hugetlb_lock);
3802 if (is_hugepage_on_freelist(hpage)) {
3804 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3805 * but dangling hpage->lru can trigger list-debug warnings
3806 * (this happens when we call unpoison_memory() on it),
3807 * so let it point to itself with list_del_init().
3809 list_del_init(&hpage->lru);
3810 set_page_refcounted(hpage);
3811 h->free_huge_pages--;
3812 h->free_huge_pages_node[nid]--;
3815 spin_unlock(&hugetlb_lock);
3820 bool isolate_huge_page(struct page *page, struct list_head *list)
3822 VM_BUG_ON_PAGE(!PageHead(page), page);
3823 if (!get_page_unless_zero(page))
3825 spin_lock(&hugetlb_lock);
3826 list_move_tail(&page->lru, list);
3827 spin_unlock(&hugetlb_lock);
3831 void putback_active_hugepage(struct page *page)
3833 VM_BUG_ON_PAGE(!PageHead(page), page);
3834 spin_lock(&hugetlb_lock);
3835 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3836 spin_unlock(&hugetlb_lock);
3840 bool is_hugepage_active(struct page *page)
3842 VM_BUG_ON_PAGE(!PageHuge(page), page);
3844 * This function can be called for a tail page because the caller,
3845 * scan_movable_pages, scans through a given pfn-range which typically
3846 * covers one memory block. In systems using gigantic hugepage (1GB
3847 * for x86_64,) a hugepage is larger than a memory block, and we don't
3848 * support migrating such large hugepages for now, so return false
3849 * when called for tail pages.
3854 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3855 * so we should return false for them.
3857 if (unlikely(PageHWPoison(page)))
3859 return page_count(page) > 0;