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/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
24 #include <linux/page-isolation.h>
27 #include <asm/pgtable.h>
31 #include <linux/hugetlb.h>
32 #include <linux/hugetlb_cgroup.h>
33 #include <linux/node.h>
36 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
37 unsigned long hugepages_treat_as_movable;
39 int hugetlb_max_hstate __read_mostly;
40 unsigned int default_hstate_idx;
41 struct hstate hstates[HUGE_MAX_HSTATE];
43 __initdata LIST_HEAD(huge_boot_pages);
45 /* for command line parsing */
46 static struct hstate * __initdata parsed_hstate;
47 static unsigned long __initdata default_hstate_max_huge_pages;
48 static unsigned long __initdata default_hstate_size;
51 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
52 * free_huge_pages, and surplus_huge_pages.
54 DEFINE_SPINLOCK(hugetlb_lock);
56 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
58 bool free = (spool->count == 0) && (spool->used_hpages == 0);
60 spin_unlock(&spool->lock);
62 /* If no pages are used, and no other handles to the subpool
63 * remain, free the subpool the subpool remain */
68 struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
70 struct hugepage_subpool *spool;
72 spool = kmalloc(sizeof(*spool), GFP_KERNEL);
76 spin_lock_init(&spool->lock);
78 spool->max_hpages = nr_blocks;
79 spool->used_hpages = 0;
84 void hugepage_put_subpool(struct hugepage_subpool *spool)
86 spin_lock(&spool->lock);
87 BUG_ON(!spool->count);
89 unlock_or_release_subpool(spool);
92 static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
100 spin_lock(&spool->lock);
101 if ((spool->used_hpages + delta) <= spool->max_hpages) {
102 spool->used_hpages += delta;
106 spin_unlock(&spool->lock);
111 static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
117 spin_lock(&spool->lock);
118 spool->used_hpages -= delta;
119 /* If hugetlbfs_put_super couldn't free spool due to
120 * an outstanding quota reference, free it now. */
121 unlock_or_release_subpool(spool);
124 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
126 return HUGETLBFS_SB(inode->i_sb)->spool;
129 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
131 return subpool_inode(file_inode(vma->vm_file));
135 * Region tracking -- allows tracking of reservations and instantiated pages
136 * across the pages in a mapping.
138 * The region data structures are protected by a combination of the mmap_sem
139 * and the hugetlb_instantiation_mutex. To access or modify a region the caller
140 * must either hold the mmap_sem for write, or the mmap_sem for read and
141 * the hugetlb_instantiation_mutex:
143 * down_write(&mm->mmap_sem);
145 * down_read(&mm->mmap_sem);
146 * mutex_lock(&hugetlb_instantiation_mutex);
149 struct list_head link;
154 static long region_add(struct list_head *head, long f, long t)
156 struct file_region *rg, *nrg, *trg;
158 /* Locate the region we are either in or before. */
159 list_for_each_entry(rg, head, link)
163 /* Round our left edge to the current segment if it encloses us. */
167 /* Check for and consume any regions we now overlap with. */
169 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
170 if (&rg->link == head)
175 /* If this area reaches higher then extend our area to
176 * include it completely. If this is not the first area
177 * which we intend to reuse, free it. */
190 static long region_chg(struct list_head *head, long f, long t)
192 struct file_region *rg, *nrg;
195 /* Locate the region we are before or in. */
196 list_for_each_entry(rg, head, link)
200 /* If we are below the current region then a new region is required.
201 * Subtle, allocate a new region at the position but make it zero
202 * size such that we can guarantee to record the reservation. */
203 if (&rg->link == head || t < rg->from) {
204 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
209 INIT_LIST_HEAD(&nrg->link);
210 list_add(&nrg->link, rg->link.prev);
215 /* Round our left edge to the current segment if it encloses us. */
220 /* Check for and consume any regions we now overlap with. */
221 list_for_each_entry(rg, rg->link.prev, link) {
222 if (&rg->link == head)
227 /* We overlap with this area, if it extends further than
228 * us then we must extend ourselves. Account for its
229 * existing reservation. */
234 chg -= rg->to - rg->from;
239 static long region_truncate(struct list_head *head, long end)
241 struct file_region *rg, *trg;
244 /* Locate the region we are either in or before. */
245 list_for_each_entry(rg, head, link)
248 if (&rg->link == head)
251 /* If we are in the middle of a region then adjust it. */
252 if (end > rg->from) {
255 rg = list_entry(rg->link.next, typeof(*rg), link);
258 /* Drop any remaining regions. */
259 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
260 if (&rg->link == head)
262 chg += rg->to - rg->from;
269 static long region_count(struct list_head *head, long f, long t)
271 struct file_region *rg;
274 /* Locate each segment we overlap with, and count that overlap. */
275 list_for_each_entry(rg, head, link) {
284 seg_from = max(rg->from, f);
285 seg_to = min(rg->to, t);
287 chg += seg_to - seg_from;
294 * Convert the address within this vma to the page offset within
295 * the mapping, in pagecache page units; huge pages here.
297 static pgoff_t vma_hugecache_offset(struct hstate *h,
298 struct vm_area_struct *vma, unsigned long address)
300 return ((address - vma->vm_start) >> huge_page_shift(h)) +
301 (vma->vm_pgoff >> huge_page_order(h));
304 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
305 unsigned long address)
307 return vma_hugecache_offset(hstate_vma(vma), vma, address);
311 * Return the size of the pages allocated when backing a VMA. In the majority
312 * cases this will be same size as used by the page table entries.
314 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
316 struct hstate *hstate;
318 if (!is_vm_hugetlb_page(vma))
321 hstate = hstate_vma(vma);
323 return 1UL << huge_page_shift(hstate);
325 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
328 * Return the page size being used by the MMU to back a VMA. In the majority
329 * of cases, the page size used by the kernel matches the MMU size. On
330 * architectures where it differs, an architecture-specific version of this
331 * function is required.
333 #ifndef vma_mmu_pagesize
334 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
336 return vma_kernel_pagesize(vma);
341 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
342 * bits of the reservation map pointer, which are always clear due to
345 #define HPAGE_RESV_OWNER (1UL << 0)
346 #define HPAGE_RESV_UNMAPPED (1UL << 1)
347 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
350 * These helpers are used to track how many pages are reserved for
351 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
352 * is guaranteed to have their future faults succeed.
354 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
355 * the reserve counters are updated with the hugetlb_lock held. It is safe
356 * to reset the VMA at fork() time as it is not in use yet and there is no
357 * chance of the global counters getting corrupted as a result of the values.
359 * The private mapping reservation is represented in a subtly different
360 * manner to a shared mapping. A shared mapping has a region map associated
361 * with the underlying file, this region map represents the backing file
362 * pages which have ever had a reservation assigned which this persists even
363 * after the page is instantiated. A private mapping has a region map
364 * associated with the original mmap which is attached to all VMAs which
365 * reference it, this region map represents those offsets which have consumed
366 * reservation ie. where pages have been instantiated.
368 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
370 return (unsigned long)vma->vm_private_data;
373 static void set_vma_private_data(struct vm_area_struct *vma,
376 vma->vm_private_data = (void *)value;
381 struct list_head regions;
384 static struct resv_map *resv_map_alloc(void)
386 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
390 kref_init(&resv_map->refs);
391 INIT_LIST_HEAD(&resv_map->regions);
396 static void resv_map_release(struct kref *ref)
398 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
400 /* Clear out any active regions before we release the map. */
401 region_truncate(&resv_map->regions, 0);
405 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
407 VM_BUG_ON(!is_vm_hugetlb_page(vma));
408 if (!(vma->vm_flags & VM_MAYSHARE))
409 return (struct resv_map *)(get_vma_private_data(vma) &
414 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
416 VM_BUG_ON(!is_vm_hugetlb_page(vma));
417 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
419 set_vma_private_data(vma, (get_vma_private_data(vma) &
420 HPAGE_RESV_MASK) | (unsigned long)map);
423 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
425 VM_BUG_ON(!is_vm_hugetlb_page(vma));
426 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
428 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
431 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
433 VM_BUG_ON(!is_vm_hugetlb_page(vma));
435 return (get_vma_private_data(vma) & flag) != 0;
438 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
439 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
441 VM_BUG_ON(!is_vm_hugetlb_page(vma));
442 if (!(vma->vm_flags & VM_MAYSHARE))
443 vma->vm_private_data = (void *)0;
446 /* Returns true if the VMA has associated reserve pages */
447 static int vma_has_reserves(struct vm_area_struct *vma, long chg)
449 if (vma->vm_flags & VM_NORESERVE) {
451 * This address is already reserved by other process(chg == 0),
452 * so, we should decrement reserved count. Without decrementing,
453 * reserve count remains after releasing inode, because this
454 * allocated page will go into page cache and is regarded as
455 * coming from reserved pool in releasing step. Currently, we
456 * don't have any other solution to deal with this situation
457 * properly, so add work-around here.
459 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
465 /* Shared mappings always use reserves */
466 if (vma->vm_flags & VM_MAYSHARE)
470 * Only the process that called mmap() has reserves for
473 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
479 static void enqueue_huge_page(struct hstate *h, struct page *page)
481 int nid = page_to_nid(page);
482 list_move(&page->lru, &h->hugepage_freelists[nid]);
483 h->free_huge_pages++;
484 h->free_huge_pages_node[nid]++;
487 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
491 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
492 if (!is_migrate_isolate_page(page))
495 * if 'non-isolated free hugepage' not found on the list,
496 * the allocation fails.
498 if (&h->hugepage_freelists[nid] == &page->lru)
500 list_move(&page->lru, &h->hugepage_activelist);
501 set_page_refcounted(page);
502 h->free_huge_pages--;
503 h->free_huge_pages_node[nid]--;
507 /* Movability of hugepages depends on migration support. */
508 static inline gfp_t htlb_alloc_mask(struct hstate *h)
510 if (hugepages_treat_as_movable || hugepage_migration_support(h))
511 return GFP_HIGHUSER_MOVABLE;
516 static struct page *dequeue_huge_page_vma(struct hstate *h,
517 struct vm_area_struct *vma,
518 unsigned long address, int avoid_reserve,
521 struct page *page = NULL;
522 struct mempolicy *mpol;
523 nodemask_t *nodemask;
524 struct zonelist *zonelist;
527 unsigned int cpuset_mems_cookie;
530 * A child process with MAP_PRIVATE mappings created by their parent
531 * have no page reserves. This check ensures that reservations are
532 * not "stolen". The child may still get SIGKILLed
534 if (!vma_has_reserves(vma, chg) &&
535 h->free_huge_pages - h->resv_huge_pages == 0)
538 /* If reserves cannot be used, ensure enough pages are in the pool */
539 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
543 cpuset_mems_cookie = get_mems_allowed();
544 zonelist = huge_zonelist(vma, address,
545 htlb_alloc_mask(h), &mpol, &nodemask);
547 for_each_zone_zonelist_nodemask(zone, z, zonelist,
548 MAX_NR_ZONES - 1, nodemask) {
549 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) {
550 page = dequeue_huge_page_node(h, zone_to_nid(zone));
554 if (!vma_has_reserves(vma, chg))
557 SetPagePrivate(page);
558 h->resv_huge_pages--;
565 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
573 static void update_and_free_page(struct hstate *h, struct page *page)
577 VM_BUG_ON(h->order >= MAX_ORDER);
580 h->nr_huge_pages_node[page_to_nid(page)]--;
581 for (i = 0; i < pages_per_huge_page(h); i++) {
582 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
583 1 << PG_referenced | 1 << PG_dirty |
584 1 << PG_active | 1 << PG_reserved |
585 1 << PG_private | 1 << PG_writeback);
587 VM_BUG_ON(hugetlb_cgroup_from_page(page));
588 set_compound_page_dtor(page, NULL);
589 set_page_refcounted(page);
590 arch_release_hugepage(page);
591 __free_pages(page, huge_page_order(h));
594 struct hstate *size_to_hstate(unsigned long size)
599 if (huge_page_size(h) == size)
605 static void free_huge_page(struct page *page)
608 * Can't pass hstate in here because it is called from the
609 * compound page destructor.
611 struct hstate *h = page_hstate(page);
612 int nid = page_to_nid(page);
613 struct hugepage_subpool *spool =
614 (struct hugepage_subpool *)page_private(page);
615 bool restore_reserve;
617 set_page_private(page, 0);
618 page->mapping = NULL;
619 BUG_ON(page_count(page));
620 BUG_ON(page_mapcount(page));
621 restore_reserve = PagePrivate(page);
622 ClearPagePrivate(page);
624 spin_lock(&hugetlb_lock);
625 hugetlb_cgroup_uncharge_page(hstate_index(h),
626 pages_per_huge_page(h), page);
628 h->resv_huge_pages++;
630 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
631 /* remove the page from active list */
632 list_del(&page->lru);
633 update_and_free_page(h, page);
634 h->surplus_huge_pages--;
635 h->surplus_huge_pages_node[nid]--;
637 arch_clear_hugepage_flags(page);
638 enqueue_huge_page(h, page);
640 spin_unlock(&hugetlb_lock);
641 hugepage_subpool_put_pages(spool, 1);
644 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
646 INIT_LIST_HEAD(&page->lru);
647 set_compound_page_dtor(page, free_huge_page);
648 spin_lock(&hugetlb_lock);
649 set_hugetlb_cgroup(page, NULL);
651 h->nr_huge_pages_node[nid]++;
652 spin_unlock(&hugetlb_lock);
653 put_page(page); /* free it into the hugepage allocator */
656 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
659 int nr_pages = 1 << order;
660 struct page *p = page + 1;
662 /* we rely on prep_new_huge_page to set the destructor */
663 set_compound_order(page, order);
665 __ClearPageReserved(page);
666 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
669 * For gigantic hugepages allocated through bootmem at
670 * boot, it's safer to be consistent with the not-gigantic
671 * hugepages and clear the PG_reserved bit from all tail pages
672 * too. Otherwse drivers using get_user_pages() to access tail
673 * pages may get the reference counting wrong if they see
674 * PG_reserved set on a tail page (despite the head page not
675 * having PG_reserved set). Enforcing this consistency between
676 * head and tail pages allows drivers to optimize away a check
677 * on the head page when they need know if put_page() is needed
678 * after get_user_pages().
680 __ClearPageReserved(p);
681 set_page_count(p, 0);
682 p->first_page = page;
687 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
688 * transparent huge pages. See the PageTransHuge() documentation for more
691 int PageHuge(struct page *page)
693 if (!PageCompound(page))
696 page = compound_head(page);
697 return get_compound_page_dtor(page) == free_huge_page;
699 EXPORT_SYMBOL_GPL(PageHuge);
702 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
703 * normal or transparent huge pages.
705 int PageHeadHuge(struct page *page_head)
707 if (!PageHead(page_head))
710 return get_compound_page_dtor(page_head) == free_huge_page;
712 EXPORT_SYMBOL_GPL(PageHeadHuge);
714 pgoff_t __basepage_index(struct page *page)
716 struct page *page_head = compound_head(page);
717 pgoff_t index = page_index(page_head);
718 unsigned long compound_idx;
720 if (!PageHuge(page_head))
721 return page_index(page);
723 if (compound_order(page_head) >= MAX_ORDER)
724 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
726 compound_idx = page - page_head;
728 return (index << compound_order(page_head)) + compound_idx;
731 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
735 if (h->order >= MAX_ORDER)
738 page = alloc_pages_exact_node(nid,
739 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
740 __GFP_REPEAT|__GFP_NOWARN,
743 if (arch_prepare_hugepage(page)) {
744 __free_pages(page, huge_page_order(h));
747 prep_new_huge_page(h, page, nid);
754 * common helper functions for hstate_next_node_to_{alloc|free}.
755 * We may have allocated or freed a huge page based on a different
756 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
757 * be outside of *nodes_allowed. Ensure that we use an allowed
758 * node for alloc or free.
760 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
762 nid = next_node(nid, *nodes_allowed);
763 if (nid == MAX_NUMNODES)
764 nid = first_node(*nodes_allowed);
765 VM_BUG_ON(nid >= MAX_NUMNODES);
770 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
772 if (!node_isset(nid, *nodes_allowed))
773 nid = next_node_allowed(nid, nodes_allowed);
778 * returns the previously saved node ["this node"] from which to
779 * allocate a persistent huge page for the pool and advance the
780 * next node from which to allocate, handling wrap at end of node
783 static int hstate_next_node_to_alloc(struct hstate *h,
784 nodemask_t *nodes_allowed)
788 VM_BUG_ON(!nodes_allowed);
790 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
791 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
797 * helper for free_pool_huge_page() - return the previously saved
798 * node ["this node"] from which to free a huge page. Advance the
799 * next node id whether or not we find a free huge page to free so
800 * that the next attempt to free addresses the next node.
802 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
806 VM_BUG_ON(!nodes_allowed);
808 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
809 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
814 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
815 for (nr_nodes = nodes_weight(*mask); \
817 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
820 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
821 for (nr_nodes = nodes_weight(*mask); \
823 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
826 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
832 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
833 page = alloc_fresh_huge_page_node(h, node);
841 count_vm_event(HTLB_BUDDY_PGALLOC);
843 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
849 * Free huge page from pool from next node to free.
850 * Attempt to keep persistent huge pages more or less
851 * balanced over allowed nodes.
852 * Called with hugetlb_lock locked.
854 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
860 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
862 * If we're returning unused surplus pages, only examine
863 * nodes with surplus pages.
865 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
866 !list_empty(&h->hugepage_freelists[node])) {
868 list_entry(h->hugepage_freelists[node].next,
870 list_del(&page->lru);
871 h->free_huge_pages--;
872 h->free_huge_pages_node[node]--;
874 h->surplus_huge_pages--;
875 h->surplus_huge_pages_node[node]--;
877 update_and_free_page(h, page);
887 * Dissolve a given free hugepage into free buddy pages. This function does
888 * nothing for in-use (including surplus) hugepages.
890 static void dissolve_free_huge_page(struct page *page)
892 spin_lock(&hugetlb_lock);
893 if (PageHuge(page) && !page_count(page)) {
894 struct hstate *h = page_hstate(page);
895 int nid = page_to_nid(page);
896 list_del(&page->lru);
897 h->free_huge_pages--;
898 h->free_huge_pages_node[nid]--;
899 update_and_free_page(h, page);
901 spin_unlock(&hugetlb_lock);
905 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
906 * make specified memory blocks removable from the system.
907 * Note that start_pfn should aligned with (minimum) hugepage size.
909 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
911 unsigned int order = 8 * sizeof(void *);
915 /* Set scan step to minimum hugepage size */
917 if (order > huge_page_order(h))
918 order = huge_page_order(h);
919 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
920 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
921 dissolve_free_huge_page(pfn_to_page(pfn));
924 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
929 if (h->order >= MAX_ORDER)
933 * Assume we will successfully allocate the surplus page to
934 * prevent racing processes from causing the surplus to exceed
937 * This however introduces a different race, where a process B
938 * tries to grow the static hugepage pool while alloc_pages() is
939 * called by process A. B will only examine the per-node
940 * counters in determining if surplus huge pages can be
941 * converted to normal huge pages in adjust_pool_surplus(). A
942 * won't be able to increment the per-node counter, until the
943 * lock is dropped by B, but B doesn't drop hugetlb_lock until
944 * no more huge pages can be converted from surplus to normal
945 * state (and doesn't try to convert again). Thus, we have a
946 * case where a surplus huge page exists, the pool is grown, and
947 * the surplus huge page still exists after, even though it
948 * should just have been converted to a normal huge page. This
949 * does not leak memory, though, as the hugepage will be freed
950 * once it is out of use. It also does not allow the counters to
951 * go out of whack in adjust_pool_surplus() as we don't modify
952 * the node values until we've gotten the hugepage and only the
953 * per-node value is checked there.
955 spin_lock(&hugetlb_lock);
956 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
957 spin_unlock(&hugetlb_lock);
961 h->surplus_huge_pages++;
963 spin_unlock(&hugetlb_lock);
965 if (nid == NUMA_NO_NODE)
966 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
967 __GFP_REPEAT|__GFP_NOWARN,
970 page = alloc_pages_exact_node(nid,
971 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
972 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
974 if (page && arch_prepare_hugepage(page)) {
975 __free_pages(page, huge_page_order(h));
979 spin_lock(&hugetlb_lock);
981 INIT_LIST_HEAD(&page->lru);
982 r_nid = page_to_nid(page);
983 set_compound_page_dtor(page, free_huge_page);
984 set_hugetlb_cgroup(page, NULL);
986 * We incremented the global counters already
988 h->nr_huge_pages_node[r_nid]++;
989 h->surplus_huge_pages_node[r_nid]++;
990 __count_vm_event(HTLB_BUDDY_PGALLOC);
993 h->surplus_huge_pages--;
994 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
996 spin_unlock(&hugetlb_lock);
1002 * This allocation function is useful in the context where vma is irrelevant.
1003 * E.g. soft-offlining uses this function because it only cares physical
1004 * address of error page.
1006 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1008 struct page *page = NULL;
1010 spin_lock(&hugetlb_lock);
1011 if (h->free_huge_pages - h->resv_huge_pages > 0)
1012 page = dequeue_huge_page_node(h, nid);
1013 spin_unlock(&hugetlb_lock);
1016 page = alloc_buddy_huge_page(h, nid);
1022 * Increase the hugetlb pool such that it can accommodate a reservation
1025 static int gather_surplus_pages(struct hstate *h, int delta)
1027 struct list_head surplus_list;
1028 struct page *page, *tmp;
1030 int needed, allocated;
1031 bool alloc_ok = true;
1033 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1035 h->resv_huge_pages += delta;
1040 INIT_LIST_HEAD(&surplus_list);
1044 spin_unlock(&hugetlb_lock);
1045 for (i = 0; i < needed; i++) {
1046 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1051 list_add(&page->lru, &surplus_list);
1056 * After retaking hugetlb_lock, we need to recalculate 'needed'
1057 * because either resv_huge_pages or free_huge_pages may have changed.
1059 spin_lock(&hugetlb_lock);
1060 needed = (h->resv_huge_pages + delta) -
1061 (h->free_huge_pages + allocated);
1066 * We were not able to allocate enough pages to
1067 * satisfy the entire reservation so we free what
1068 * we've allocated so far.
1073 * The surplus_list now contains _at_least_ the number of extra pages
1074 * needed to accommodate the reservation. Add the appropriate number
1075 * of pages to the hugetlb pool and free the extras back to the buddy
1076 * allocator. Commit the entire reservation here to prevent another
1077 * process from stealing the pages as they are added to the pool but
1078 * before they are reserved.
1080 needed += allocated;
1081 h->resv_huge_pages += delta;
1084 /* Free the needed pages to the hugetlb pool */
1085 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1089 * This page is now managed by the hugetlb allocator and has
1090 * no users -- drop the buddy allocator's reference.
1092 put_page_testzero(page);
1093 VM_BUG_ON(page_count(page));
1094 enqueue_huge_page(h, page);
1097 spin_unlock(&hugetlb_lock);
1099 /* Free unnecessary surplus pages to the buddy allocator */
1100 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1102 spin_lock(&hugetlb_lock);
1108 * When releasing a hugetlb pool reservation, any surplus pages that were
1109 * allocated to satisfy the reservation must be explicitly freed if they were
1111 * Called with hugetlb_lock held.
1113 static void return_unused_surplus_pages(struct hstate *h,
1114 unsigned long unused_resv_pages)
1116 unsigned long nr_pages;
1118 /* Uncommit the reservation */
1119 h->resv_huge_pages -= unused_resv_pages;
1121 /* Cannot return gigantic pages currently */
1122 if (h->order >= MAX_ORDER)
1125 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1128 * We want to release as many surplus pages as possible, spread
1129 * evenly across all nodes with memory. Iterate across these nodes
1130 * until we can no longer free unreserved surplus pages. This occurs
1131 * when the nodes with surplus pages have no free pages.
1132 * free_pool_huge_page() will balance the the freed pages across the
1133 * on-line nodes with memory and will handle the hstate accounting.
1135 while (nr_pages--) {
1136 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1142 * Determine if the huge page at addr within the vma has an associated
1143 * reservation. Where it does not we will need to logically increase
1144 * reservation and actually increase subpool usage before an allocation
1145 * can occur. Where any new reservation would be required the
1146 * reservation change is prepared, but not committed. Once the page
1147 * has been allocated from the subpool and instantiated the change should
1148 * be committed via vma_commit_reservation. No action is required on
1151 static long vma_needs_reservation(struct hstate *h,
1152 struct vm_area_struct *vma, unsigned long addr)
1154 struct address_space *mapping = vma->vm_file->f_mapping;
1155 struct inode *inode = mapping->host;
1157 if (vma->vm_flags & VM_MAYSHARE) {
1158 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1159 return region_chg(&inode->i_mapping->private_list,
1162 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1167 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1168 struct resv_map *resv = vma_resv_map(vma);
1170 err = region_chg(&resv->regions, idx, idx + 1);
1176 static void vma_commit_reservation(struct hstate *h,
1177 struct vm_area_struct *vma, unsigned long addr)
1179 struct address_space *mapping = vma->vm_file->f_mapping;
1180 struct inode *inode = mapping->host;
1182 if (vma->vm_flags & VM_MAYSHARE) {
1183 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1184 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1186 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1187 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1188 struct resv_map *resv = vma_resv_map(vma);
1190 /* Mark this page used in the map. */
1191 region_add(&resv->regions, idx, idx + 1);
1195 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1196 unsigned long addr, int avoid_reserve)
1198 struct hugepage_subpool *spool = subpool_vma(vma);
1199 struct hstate *h = hstate_vma(vma);
1203 struct hugetlb_cgroup *h_cg;
1205 idx = hstate_index(h);
1207 * Processes that did not create the mapping will have no
1208 * reserves and will not have accounted against subpool
1209 * limit. Check that the subpool limit can be made before
1210 * satisfying the allocation MAP_NORESERVE mappings may also
1211 * need pages and subpool limit allocated allocated if no reserve
1214 chg = vma_needs_reservation(h, vma, addr);
1216 return ERR_PTR(-ENOMEM);
1217 if (chg || avoid_reserve)
1218 if (hugepage_subpool_get_pages(spool, 1))
1219 return ERR_PTR(-ENOSPC);
1221 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1223 if (chg || avoid_reserve)
1224 hugepage_subpool_put_pages(spool, 1);
1225 return ERR_PTR(-ENOSPC);
1227 spin_lock(&hugetlb_lock);
1228 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1230 spin_unlock(&hugetlb_lock);
1231 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1233 hugetlb_cgroup_uncharge_cgroup(idx,
1234 pages_per_huge_page(h),
1236 if (chg || avoid_reserve)
1237 hugepage_subpool_put_pages(spool, 1);
1238 return ERR_PTR(-ENOSPC);
1240 spin_lock(&hugetlb_lock);
1241 list_move(&page->lru, &h->hugepage_activelist);
1244 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1245 spin_unlock(&hugetlb_lock);
1247 set_page_private(page, (unsigned long)spool);
1249 vma_commit_reservation(h, vma, addr);
1254 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1255 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1256 * where no ERR_VALUE is expected to be returned.
1258 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1259 unsigned long addr, int avoid_reserve)
1261 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1267 int __weak alloc_bootmem_huge_page(struct hstate *h)
1269 struct huge_bootmem_page *m;
1272 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1275 addr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
1276 huge_page_size(h), huge_page_size(h), 0);
1280 * Use the beginning of the huge page to store the
1281 * huge_bootmem_page struct (until gather_bootmem
1282 * puts them into the mem_map).
1291 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1292 /* Put them into a private list first because mem_map is not up yet */
1293 list_add(&m->list, &huge_boot_pages);
1298 static void prep_compound_huge_page(struct page *page, int order)
1300 if (unlikely(order > (MAX_ORDER - 1)))
1301 prep_compound_gigantic_page(page, order);
1303 prep_compound_page(page, order);
1306 /* Put bootmem huge pages into the standard lists after mem_map is up */
1307 static void __init gather_bootmem_prealloc(void)
1309 struct huge_bootmem_page *m;
1311 list_for_each_entry(m, &huge_boot_pages, list) {
1312 struct hstate *h = m->hstate;
1315 #ifdef CONFIG_HIGHMEM
1316 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1317 free_bootmem_late((unsigned long)m,
1318 sizeof(struct huge_bootmem_page));
1320 page = virt_to_page(m);
1322 WARN_ON(page_count(page) != 1);
1323 prep_compound_huge_page(page, h->order);
1324 WARN_ON(PageReserved(page));
1325 prep_new_huge_page(h, page, page_to_nid(page));
1327 * If we had gigantic hugepages allocated at boot time, we need
1328 * to restore the 'stolen' pages to totalram_pages in order to
1329 * fix confusing memory reports from free(1) and another
1330 * side-effects, like CommitLimit going negative.
1332 if (h->order > (MAX_ORDER - 1))
1333 adjust_managed_page_count(page, 1 << h->order);
1337 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1341 for (i = 0; i < h->max_huge_pages; ++i) {
1342 if (h->order >= MAX_ORDER) {
1343 if (!alloc_bootmem_huge_page(h))
1345 } else if (!alloc_fresh_huge_page(h,
1346 &node_states[N_MEMORY]))
1349 h->max_huge_pages = i;
1352 static void __init hugetlb_init_hstates(void)
1356 for_each_hstate(h) {
1357 /* oversize hugepages were init'ed in early boot */
1358 if (h->order < MAX_ORDER)
1359 hugetlb_hstate_alloc_pages(h);
1363 static char * __init memfmt(char *buf, unsigned long n)
1365 if (n >= (1UL << 30))
1366 sprintf(buf, "%lu GB", n >> 30);
1367 else if (n >= (1UL << 20))
1368 sprintf(buf, "%lu MB", n >> 20);
1370 sprintf(buf, "%lu KB", n >> 10);
1374 static void __init report_hugepages(void)
1378 for_each_hstate(h) {
1380 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1381 memfmt(buf, huge_page_size(h)),
1382 h->free_huge_pages);
1386 #ifdef CONFIG_HIGHMEM
1387 static void try_to_free_low(struct hstate *h, unsigned long count,
1388 nodemask_t *nodes_allowed)
1392 if (h->order >= MAX_ORDER)
1395 for_each_node_mask(i, *nodes_allowed) {
1396 struct page *page, *next;
1397 struct list_head *freel = &h->hugepage_freelists[i];
1398 list_for_each_entry_safe(page, next, freel, lru) {
1399 if (count >= h->nr_huge_pages)
1401 if (PageHighMem(page))
1403 list_del(&page->lru);
1404 update_and_free_page(h, page);
1405 h->free_huge_pages--;
1406 h->free_huge_pages_node[page_to_nid(page)]--;
1411 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1412 nodemask_t *nodes_allowed)
1418 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1419 * balanced by operating on them in a round-robin fashion.
1420 * Returns 1 if an adjustment was made.
1422 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1427 VM_BUG_ON(delta != -1 && delta != 1);
1430 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1431 if (h->surplus_huge_pages_node[node])
1435 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1436 if (h->surplus_huge_pages_node[node] <
1437 h->nr_huge_pages_node[node])
1444 h->surplus_huge_pages += delta;
1445 h->surplus_huge_pages_node[node] += delta;
1449 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1450 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1451 nodemask_t *nodes_allowed)
1453 unsigned long min_count, ret;
1455 if (h->order >= MAX_ORDER)
1456 return h->max_huge_pages;
1459 * Increase the pool size
1460 * First take pages out of surplus state. Then make up the
1461 * remaining difference by allocating fresh huge pages.
1463 * We might race with alloc_buddy_huge_page() here and be unable
1464 * to convert a surplus huge page to a normal huge page. That is
1465 * not critical, though, it just means the overall size of the
1466 * pool might be one hugepage larger than it needs to be, but
1467 * within all the constraints specified by the sysctls.
1469 spin_lock(&hugetlb_lock);
1470 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1471 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1475 while (count > persistent_huge_pages(h)) {
1477 * If this allocation races such that we no longer need the
1478 * page, free_huge_page will handle it by freeing the page
1479 * and reducing the surplus.
1481 spin_unlock(&hugetlb_lock);
1482 ret = alloc_fresh_huge_page(h, nodes_allowed);
1483 spin_lock(&hugetlb_lock);
1487 /* Bail for signals. Probably ctrl-c from user */
1488 if (signal_pending(current))
1493 * Decrease the pool size
1494 * First return free pages to the buddy allocator (being careful
1495 * to keep enough around to satisfy reservations). Then place
1496 * pages into surplus state as needed so the pool will shrink
1497 * to the desired size as pages become free.
1499 * By placing pages into the surplus state independent of the
1500 * overcommit value, we are allowing the surplus pool size to
1501 * exceed overcommit. There are few sane options here. Since
1502 * alloc_buddy_huge_page() is checking the global counter,
1503 * though, we'll note that we're not allowed to exceed surplus
1504 * and won't grow the pool anywhere else. Not until one of the
1505 * sysctls are changed, or the surplus pages go out of use.
1507 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1508 min_count = max(count, min_count);
1509 try_to_free_low(h, min_count, nodes_allowed);
1510 while (min_count < persistent_huge_pages(h)) {
1511 if (!free_pool_huge_page(h, nodes_allowed, 0))
1514 while (count < persistent_huge_pages(h)) {
1515 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1519 ret = persistent_huge_pages(h);
1520 spin_unlock(&hugetlb_lock);
1524 #define HSTATE_ATTR_RO(_name) \
1525 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1527 #define HSTATE_ATTR(_name) \
1528 static struct kobj_attribute _name##_attr = \
1529 __ATTR(_name, 0644, _name##_show, _name##_store)
1531 static struct kobject *hugepages_kobj;
1532 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1534 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1536 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1540 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1541 if (hstate_kobjs[i] == kobj) {
1543 *nidp = NUMA_NO_NODE;
1547 return kobj_to_node_hstate(kobj, nidp);
1550 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1551 struct kobj_attribute *attr, char *buf)
1554 unsigned long nr_huge_pages;
1557 h = kobj_to_hstate(kobj, &nid);
1558 if (nid == NUMA_NO_NODE)
1559 nr_huge_pages = h->nr_huge_pages;
1561 nr_huge_pages = h->nr_huge_pages_node[nid];
1563 return sprintf(buf, "%lu\n", nr_huge_pages);
1566 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1567 struct kobject *kobj, struct kobj_attribute *attr,
1568 const char *buf, size_t len)
1572 unsigned long count;
1574 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1576 err = kstrtoul(buf, 10, &count);
1580 h = kobj_to_hstate(kobj, &nid);
1581 if (h->order >= MAX_ORDER) {
1586 if (nid == NUMA_NO_NODE) {
1588 * global hstate attribute
1590 if (!(obey_mempolicy &&
1591 init_nodemask_of_mempolicy(nodes_allowed))) {
1592 NODEMASK_FREE(nodes_allowed);
1593 nodes_allowed = &node_states[N_MEMORY];
1595 } else if (nodes_allowed) {
1597 * per node hstate attribute: adjust count to global,
1598 * but restrict alloc/free to the specified node.
1600 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1601 init_nodemask_of_node(nodes_allowed, nid);
1603 nodes_allowed = &node_states[N_MEMORY];
1605 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1607 if (nodes_allowed != &node_states[N_MEMORY])
1608 NODEMASK_FREE(nodes_allowed);
1612 NODEMASK_FREE(nodes_allowed);
1616 static ssize_t nr_hugepages_show(struct kobject *kobj,
1617 struct kobj_attribute *attr, char *buf)
1619 return nr_hugepages_show_common(kobj, attr, buf);
1622 static ssize_t nr_hugepages_store(struct kobject *kobj,
1623 struct kobj_attribute *attr, const char *buf, size_t len)
1625 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1627 HSTATE_ATTR(nr_hugepages);
1632 * hstate attribute for optionally mempolicy-based constraint on persistent
1633 * huge page alloc/free.
1635 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1636 struct kobj_attribute *attr, char *buf)
1638 return nr_hugepages_show_common(kobj, attr, buf);
1641 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1642 struct kobj_attribute *attr, const char *buf, size_t len)
1644 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1646 HSTATE_ATTR(nr_hugepages_mempolicy);
1650 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1651 struct kobj_attribute *attr, char *buf)
1653 struct hstate *h = kobj_to_hstate(kobj, NULL);
1654 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1657 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1658 struct kobj_attribute *attr, const char *buf, size_t count)
1661 unsigned long input;
1662 struct hstate *h = kobj_to_hstate(kobj, NULL);
1664 if (h->order >= MAX_ORDER)
1667 err = kstrtoul(buf, 10, &input);
1671 spin_lock(&hugetlb_lock);
1672 h->nr_overcommit_huge_pages = input;
1673 spin_unlock(&hugetlb_lock);
1677 HSTATE_ATTR(nr_overcommit_hugepages);
1679 static ssize_t free_hugepages_show(struct kobject *kobj,
1680 struct kobj_attribute *attr, char *buf)
1683 unsigned long free_huge_pages;
1686 h = kobj_to_hstate(kobj, &nid);
1687 if (nid == NUMA_NO_NODE)
1688 free_huge_pages = h->free_huge_pages;
1690 free_huge_pages = h->free_huge_pages_node[nid];
1692 return sprintf(buf, "%lu\n", free_huge_pages);
1694 HSTATE_ATTR_RO(free_hugepages);
1696 static ssize_t resv_hugepages_show(struct kobject *kobj,
1697 struct kobj_attribute *attr, char *buf)
1699 struct hstate *h = kobj_to_hstate(kobj, NULL);
1700 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1702 HSTATE_ATTR_RO(resv_hugepages);
1704 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1705 struct kobj_attribute *attr, char *buf)
1708 unsigned long surplus_huge_pages;
1711 h = kobj_to_hstate(kobj, &nid);
1712 if (nid == NUMA_NO_NODE)
1713 surplus_huge_pages = h->surplus_huge_pages;
1715 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1717 return sprintf(buf, "%lu\n", surplus_huge_pages);
1719 HSTATE_ATTR_RO(surplus_hugepages);
1721 static struct attribute *hstate_attrs[] = {
1722 &nr_hugepages_attr.attr,
1723 &nr_overcommit_hugepages_attr.attr,
1724 &free_hugepages_attr.attr,
1725 &resv_hugepages_attr.attr,
1726 &surplus_hugepages_attr.attr,
1728 &nr_hugepages_mempolicy_attr.attr,
1733 static struct attribute_group hstate_attr_group = {
1734 .attrs = hstate_attrs,
1737 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1738 struct kobject **hstate_kobjs,
1739 struct attribute_group *hstate_attr_group)
1742 int hi = hstate_index(h);
1744 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1745 if (!hstate_kobjs[hi])
1748 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1750 kobject_put(hstate_kobjs[hi]);
1755 static void __init hugetlb_sysfs_init(void)
1760 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1761 if (!hugepages_kobj)
1764 for_each_hstate(h) {
1765 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1766 hstate_kobjs, &hstate_attr_group);
1768 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1775 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1776 * with node devices in node_devices[] using a parallel array. The array
1777 * index of a node device or _hstate == node id.
1778 * This is here to avoid any static dependency of the node device driver, in
1779 * the base kernel, on the hugetlb module.
1781 struct node_hstate {
1782 struct kobject *hugepages_kobj;
1783 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1785 struct node_hstate node_hstates[MAX_NUMNODES];
1788 * A subset of global hstate attributes for node devices
1790 static struct attribute *per_node_hstate_attrs[] = {
1791 &nr_hugepages_attr.attr,
1792 &free_hugepages_attr.attr,
1793 &surplus_hugepages_attr.attr,
1797 static struct attribute_group per_node_hstate_attr_group = {
1798 .attrs = per_node_hstate_attrs,
1802 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1803 * Returns node id via non-NULL nidp.
1805 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1809 for (nid = 0; nid < nr_node_ids; nid++) {
1810 struct node_hstate *nhs = &node_hstates[nid];
1812 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1813 if (nhs->hstate_kobjs[i] == kobj) {
1825 * Unregister hstate attributes from a single node device.
1826 * No-op if no hstate attributes attached.
1828 static void hugetlb_unregister_node(struct node *node)
1831 struct node_hstate *nhs = &node_hstates[node->dev.id];
1833 if (!nhs->hugepages_kobj)
1834 return; /* no hstate attributes */
1836 for_each_hstate(h) {
1837 int idx = hstate_index(h);
1838 if (nhs->hstate_kobjs[idx]) {
1839 kobject_put(nhs->hstate_kobjs[idx]);
1840 nhs->hstate_kobjs[idx] = NULL;
1844 kobject_put(nhs->hugepages_kobj);
1845 nhs->hugepages_kobj = NULL;
1849 * hugetlb module exit: unregister hstate attributes from node devices
1852 static void hugetlb_unregister_all_nodes(void)
1857 * disable node device registrations.
1859 register_hugetlbfs_with_node(NULL, NULL);
1862 * remove hstate attributes from any nodes that have them.
1864 for (nid = 0; nid < nr_node_ids; nid++)
1865 hugetlb_unregister_node(node_devices[nid]);
1869 * Register hstate attributes for a single node device.
1870 * No-op if attributes already registered.
1872 static void hugetlb_register_node(struct node *node)
1875 struct node_hstate *nhs = &node_hstates[node->dev.id];
1878 if (nhs->hugepages_kobj)
1879 return; /* already allocated */
1881 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1883 if (!nhs->hugepages_kobj)
1886 for_each_hstate(h) {
1887 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1889 &per_node_hstate_attr_group);
1891 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1892 h->name, node->dev.id);
1893 hugetlb_unregister_node(node);
1900 * hugetlb init time: register hstate attributes for all registered node
1901 * devices of nodes that have memory. All on-line nodes should have
1902 * registered their associated device by this time.
1904 static void hugetlb_register_all_nodes(void)
1908 for_each_node_state(nid, N_MEMORY) {
1909 struct node *node = node_devices[nid];
1910 if (node->dev.id == nid)
1911 hugetlb_register_node(node);
1915 * Let the node device driver know we're here so it can
1916 * [un]register hstate attributes on node hotplug.
1918 register_hugetlbfs_with_node(hugetlb_register_node,
1919 hugetlb_unregister_node);
1921 #else /* !CONFIG_NUMA */
1923 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1931 static void hugetlb_unregister_all_nodes(void) { }
1933 static void hugetlb_register_all_nodes(void) { }
1937 static void __exit hugetlb_exit(void)
1941 hugetlb_unregister_all_nodes();
1943 for_each_hstate(h) {
1944 kobject_put(hstate_kobjs[hstate_index(h)]);
1947 kobject_put(hugepages_kobj);
1949 module_exit(hugetlb_exit);
1951 static int __init hugetlb_init(void)
1953 /* Some platform decide whether they support huge pages at boot
1954 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1955 * there is no such support
1957 if (HPAGE_SHIFT == 0)
1960 if (!size_to_hstate(default_hstate_size)) {
1961 default_hstate_size = HPAGE_SIZE;
1962 if (!size_to_hstate(default_hstate_size))
1963 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1965 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1966 if (default_hstate_max_huge_pages)
1967 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1969 hugetlb_init_hstates();
1970 gather_bootmem_prealloc();
1973 hugetlb_sysfs_init();
1974 hugetlb_register_all_nodes();
1975 hugetlb_cgroup_file_init();
1979 module_init(hugetlb_init);
1981 /* Should be called on processing a hugepagesz=... option */
1982 void __init hugetlb_add_hstate(unsigned order)
1987 if (size_to_hstate(PAGE_SIZE << order)) {
1988 pr_warning("hugepagesz= specified twice, ignoring\n");
1991 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
1993 h = &hstates[hugetlb_max_hstate++];
1995 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1996 h->nr_huge_pages = 0;
1997 h->free_huge_pages = 0;
1998 for (i = 0; i < MAX_NUMNODES; ++i)
1999 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2000 INIT_LIST_HEAD(&h->hugepage_activelist);
2001 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2002 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2003 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2004 huge_page_size(h)/1024);
2009 static int __init hugetlb_nrpages_setup(char *s)
2012 static unsigned long *last_mhp;
2015 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2016 * so this hugepages= parameter goes to the "default hstate".
2018 if (!hugetlb_max_hstate)
2019 mhp = &default_hstate_max_huge_pages;
2021 mhp = &parsed_hstate->max_huge_pages;
2023 if (mhp == last_mhp) {
2024 pr_warning("hugepages= specified twice without "
2025 "interleaving hugepagesz=, ignoring\n");
2029 if (sscanf(s, "%lu", mhp) <= 0)
2033 * Global state is always initialized later in hugetlb_init.
2034 * But we need to allocate >= MAX_ORDER hstates here early to still
2035 * use the bootmem allocator.
2037 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2038 hugetlb_hstate_alloc_pages(parsed_hstate);
2044 __setup("hugepages=", hugetlb_nrpages_setup);
2046 static int __init hugetlb_default_setup(char *s)
2048 default_hstate_size = memparse(s, &s);
2051 __setup("default_hugepagesz=", hugetlb_default_setup);
2053 static unsigned int cpuset_mems_nr(unsigned int *array)
2056 unsigned int nr = 0;
2058 for_each_node_mask(node, cpuset_current_mems_allowed)
2064 #ifdef CONFIG_SYSCTL
2065 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2066 struct ctl_table *table, int write,
2067 void __user *buffer, size_t *length, loff_t *ppos)
2069 struct hstate *h = &default_hstate;
2073 tmp = h->max_huge_pages;
2075 if (write && h->order >= MAX_ORDER)
2079 table->maxlen = sizeof(unsigned long);
2080 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2085 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2086 GFP_KERNEL | __GFP_NORETRY);
2087 if (!(obey_mempolicy &&
2088 init_nodemask_of_mempolicy(nodes_allowed))) {
2089 NODEMASK_FREE(nodes_allowed);
2090 nodes_allowed = &node_states[N_MEMORY];
2092 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2094 if (nodes_allowed != &node_states[N_MEMORY])
2095 NODEMASK_FREE(nodes_allowed);
2101 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2102 void __user *buffer, size_t *length, loff_t *ppos)
2105 return hugetlb_sysctl_handler_common(false, table, write,
2106 buffer, length, ppos);
2110 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2111 void __user *buffer, size_t *length, loff_t *ppos)
2113 return hugetlb_sysctl_handler_common(true, table, write,
2114 buffer, length, ppos);
2116 #endif /* CONFIG_NUMA */
2118 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2119 void __user *buffer,
2120 size_t *length, loff_t *ppos)
2122 struct hstate *h = &default_hstate;
2126 tmp = h->nr_overcommit_huge_pages;
2128 if (write && h->order >= MAX_ORDER)
2132 table->maxlen = sizeof(unsigned long);
2133 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2138 spin_lock(&hugetlb_lock);
2139 h->nr_overcommit_huge_pages = tmp;
2140 spin_unlock(&hugetlb_lock);
2146 #endif /* CONFIG_SYSCTL */
2148 void hugetlb_report_meminfo(struct seq_file *m)
2150 struct hstate *h = &default_hstate;
2152 "HugePages_Total: %5lu\n"
2153 "HugePages_Free: %5lu\n"
2154 "HugePages_Rsvd: %5lu\n"
2155 "HugePages_Surp: %5lu\n"
2156 "Hugepagesize: %8lu kB\n",
2160 h->surplus_huge_pages,
2161 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2164 int hugetlb_report_node_meminfo(int nid, char *buf)
2166 struct hstate *h = &default_hstate;
2168 "Node %d HugePages_Total: %5u\n"
2169 "Node %d HugePages_Free: %5u\n"
2170 "Node %d HugePages_Surp: %5u\n",
2171 nid, h->nr_huge_pages_node[nid],
2172 nid, h->free_huge_pages_node[nid],
2173 nid, h->surplus_huge_pages_node[nid]);
2176 void hugetlb_show_meminfo(void)
2181 for_each_node_state(nid, N_MEMORY)
2183 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2185 h->nr_huge_pages_node[nid],
2186 h->free_huge_pages_node[nid],
2187 h->surplus_huge_pages_node[nid],
2188 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2191 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2192 unsigned long hugetlb_total_pages(void)
2195 unsigned long nr_total_pages = 0;
2198 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2199 return nr_total_pages;
2202 static int hugetlb_acct_memory(struct hstate *h, long delta)
2206 spin_lock(&hugetlb_lock);
2208 * When cpuset is configured, it breaks the strict hugetlb page
2209 * reservation as the accounting is done on a global variable. Such
2210 * reservation is completely rubbish in the presence of cpuset because
2211 * the reservation is not checked against page availability for the
2212 * current cpuset. Application can still potentially OOM'ed by kernel
2213 * with lack of free htlb page in cpuset that the task is in.
2214 * Attempt to enforce strict accounting with cpuset is almost
2215 * impossible (or too ugly) because cpuset is too fluid that
2216 * task or memory node can be dynamically moved between cpusets.
2218 * The change of semantics for shared hugetlb mapping with cpuset is
2219 * undesirable. However, in order to preserve some of the semantics,
2220 * we fall back to check against current free page availability as
2221 * a best attempt and hopefully to minimize the impact of changing
2222 * semantics that cpuset has.
2225 if (gather_surplus_pages(h, delta) < 0)
2228 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2229 return_unused_surplus_pages(h, delta);
2236 return_unused_surplus_pages(h, (unsigned long) -delta);
2239 spin_unlock(&hugetlb_lock);
2243 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2245 struct resv_map *resv = vma_resv_map(vma);
2248 * This new VMA should share its siblings reservation map if present.
2249 * The VMA will only ever have a valid reservation map pointer where
2250 * it is being copied for another still existing VMA. As that VMA
2251 * has a reference to the reservation map it cannot disappear until
2252 * after this open call completes. It is therefore safe to take a
2253 * new reference here without additional locking.
2256 kref_get(&resv->refs);
2259 static void resv_map_put(struct vm_area_struct *vma)
2261 struct resv_map *resv = vma_resv_map(vma);
2265 kref_put(&resv->refs, resv_map_release);
2268 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2270 struct hstate *h = hstate_vma(vma);
2271 struct resv_map *resv = vma_resv_map(vma);
2272 struct hugepage_subpool *spool = subpool_vma(vma);
2273 unsigned long reserve;
2274 unsigned long start;
2278 start = vma_hugecache_offset(h, vma, vma->vm_start);
2279 end = vma_hugecache_offset(h, vma, vma->vm_end);
2281 reserve = (end - start) -
2282 region_count(&resv->regions, start, end);
2287 hugetlb_acct_memory(h, -reserve);
2288 hugepage_subpool_put_pages(spool, reserve);
2294 * We cannot handle pagefaults against hugetlb pages at all. They cause
2295 * handle_mm_fault() to try to instantiate regular-sized pages in the
2296 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2299 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2305 const struct vm_operations_struct hugetlb_vm_ops = {
2306 .fault = hugetlb_vm_op_fault,
2307 .open = hugetlb_vm_op_open,
2308 .close = hugetlb_vm_op_close,
2311 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2317 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2318 vma->vm_page_prot)));
2320 entry = huge_pte_wrprotect(mk_huge_pte(page,
2321 vma->vm_page_prot));
2323 entry = pte_mkyoung(entry);
2324 entry = pte_mkhuge(entry);
2325 entry = arch_make_huge_pte(entry, vma, page, writable);
2330 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2331 unsigned long address, pte_t *ptep)
2335 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2336 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2337 update_mmu_cache(vma, address, ptep);
2341 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2342 struct vm_area_struct *vma)
2344 pte_t *src_pte, *dst_pte, entry;
2345 struct page *ptepage;
2348 struct hstate *h = hstate_vma(vma);
2349 unsigned long sz = huge_page_size(h);
2351 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2353 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2354 spinlock_t *src_ptl, *dst_ptl;
2355 src_pte = huge_pte_offset(src, addr);
2358 dst_pte = huge_pte_alloc(dst, addr, sz);
2362 /* If the pagetables are shared don't copy or take references */
2363 if (dst_pte == src_pte)
2366 dst_ptl = huge_pte_lock(h, dst, dst_pte);
2367 src_ptl = huge_pte_lockptr(h, src, src_pte);
2368 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2369 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2371 huge_ptep_set_wrprotect(src, addr, src_pte);
2372 entry = huge_ptep_get(src_pte);
2373 ptepage = pte_page(entry);
2375 page_dup_rmap(ptepage);
2376 set_huge_pte_at(dst, addr, dst_pte, entry);
2378 spin_unlock(src_ptl);
2379 spin_unlock(dst_ptl);
2387 static int is_hugetlb_entry_migration(pte_t pte)
2391 if (huge_pte_none(pte) || pte_present(pte))
2393 swp = pte_to_swp_entry(pte);
2394 if (non_swap_entry(swp) && is_migration_entry(swp))
2400 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2404 if (huge_pte_none(pte) || pte_present(pte))
2406 swp = pte_to_swp_entry(pte);
2407 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2413 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2414 unsigned long start, unsigned long end,
2415 struct page *ref_page)
2417 int force_flush = 0;
2418 struct mm_struct *mm = vma->vm_mm;
2419 unsigned long address;
2424 struct hstate *h = hstate_vma(vma);
2425 unsigned long sz = huge_page_size(h);
2426 const unsigned long mmun_start = start; /* For mmu_notifiers */
2427 const unsigned long mmun_end = end; /* For mmu_notifiers */
2429 WARN_ON(!is_vm_hugetlb_page(vma));
2430 BUG_ON(start & ~huge_page_mask(h));
2431 BUG_ON(end & ~huge_page_mask(h));
2433 tlb_start_vma(tlb, vma);
2434 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2436 for (address = start; address < end; address += sz) {
2437 ptep = huge_pte_offset(mm, address);
2441 ptl = huge_pte_lock(h, mm, ptep);
2442 if (huge_pmd_unshare(mm, &address, ptep))
2445 pte = huge_ptep_get(ptep);
2446 if (huge_pte_none(pte))
2450 * HWPoisoned hugepage is already unmapped and dropped reference
2452 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2453 huge_pte_clear(mm, address, ptep);
2457 page = pte_page(pte);
2459 * If a reference page is supplied, it is because a specific
2460 * page is being unmapped, not a range. Ensure the page we
2461 * are about to unmap is the actual page of interest.
2464 if (page != ref_page)
2468 * Mark the VMA as having unmapped its page so that
2469 * future faults in this VMA will fail rather than
2470 * looking like data was lost
2472 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2475 pte = huge_ptep_get_and_clear(mm, address, ptep);
2476 tlb_remove_tlb_entry(tlb, ptep, address);
2477 if (huge_pte_dirty(pte))
2478 set_page_dirty(page);
2480 page_remove_rmap(page);
2481 force_flush = !__tlb_remove_page(tlb, page);
2486 /* Bail out after unmapping reference page if supplied */
2495 * mmu_gather ran out of room to batch pages, we break out of
2496 * the PTE lock to avoid doing the potential expensive TLB invalidate
2497 * and page-free while holding it.
2502 if (address < end && !ref_page)
2505 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2506 tlb_end_vma(tlb, vma);
2509 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2510 struct vm_area_struct *vma, unsigned long start,
2511 unsigned long end, struct page *ref_page)
2513 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2516 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2517 * test will fail on a vma being torn down, and not grab a page table
2518 * on its way out. We're lucky that the flag has such an appropriate
2519 * name, and can in fact be safely cleared here. We could clear it
2520 * before the __unmap_hugepage_range above, but all that's necessary
2521 * is to clear it before releasing the i_mmap_mutex. This works
2522 * because in the context this is called, the VMA is about to be
2523 * destroyed and the i_mmap_mutex is held.
2525 vma->vm_flags &= ~VM_MAYSHARE;
2528 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2529 unsigned long end, struct page *ref_page)
2531 struct mm_struct *mm;
2532 struct mmu_gather tlb;
2536 tlb_gather_mmu(&tlb, mm, start, end);
2537 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2538 tlb_finish_mmu(&tlb, start, end);
2542 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2543 * mappping it owns the reserve page for. The intention is to unmap the page
2544 * from other VMAs and let the children be SIGKILLed if they are faulting the
2547 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2548 struct page *page, unsigned long address)
2550 struct hstate *h = hstate_vma(vma);
2551 struct vm_area_struct *iter_vma;
2552 struct address_space *mapping;
2556 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2557 * from page cache lookup which is in HPAGE_SIZE units.
2559 address = address & huge_page_mask(h);
2560 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2562 mapping = file_inode(vma->vm_file)->i_mapping;
2565 * Take the mapping lock for the duration of the table walk. As
2566 * this mapping should be shared between all the VMAs,
2567 * __unmap_hugepage_range() is called as the lock is already held
2569 mutex_lock(&mapping->i_mmap_mutex);
2570 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2571 /* Do not unmap the current VMA */
2572 if (iter_vma == vma)
2576 * Unmap the page from other VMAs without their own reserves.
2577 * They get marked to be SIGKILLed if they fault in these
2578 * areas. This is because a future no-page fault on this VMA
2579 * could insert a zeroed page instead of the data existing
2580 * from the time of fork. This would look like data corruption
2582 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2583 unmap_hugepage_range(iter_vma, address,
2584 address + huge_page_size(h), page);
2586 mutex_unlock(&mapping->i_mmap_mutex);
2592 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2593 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2594 * cannot race with other handlers or page migration.
2595 * Keep the pte_same checks anyway to make transition from the mutex easier.
2597 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2598 unsigned long address, pte_t *ptep, pte_t pte,
2599 struct page *pagecache_page, spinlock_t *ptl)
2601 struct hstate *h = hstate_vma(vma);
2602 struct page *old_page, *new_page;
2603 int outside_reserve = 0;
2604 unsigned long mmun_start; /* For mmu_notifiers */
2605 unsigned long mmun_end; /* For mmu_notifiers */
2607 old_page = pte_page(pte);
2610 /* If no-one else is actually using this page, avoid the copy
2611 * and just make the page writable */
2612 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2613 page_move_anon_rmap(old_page, vma, address);
2614 set_huge_ptep_writable(vma, address, ptep);
2619 * If the process that created a MAP_PRIVATE mapping is about to
2620 * perform a COW due to a shared page count, attempt to satisfy
2621 * the allocation without using the existing reserves. The pagecache
2622 * page is used to determine if the reserve at this address was
2623 * consumed or not. If reserves were used, a partial faulted mapping
2624 * at the time of fork() could consume its reserves on COW instead
2625 * of the full address range.
2627 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2628 old_page != pagecache_page)
2629 outside_reserve = 1;
2631 page_cache_get(old_page);
2633 /* Drop page table lock as buddy allocator may be called */
2635 new_page = alloc_huge_page(vma, address, outside_reserve);
2637 if (IS_ERR(new_page)) {
2638 long err = PTR_ERR(new_page);
2639 page_cache_release(old_page);
2642 * If a process owning a MAP_PRIVATE mapping fails to COW,
2643 * it is due to references held by a child and an insufficient
2644 * huge page pool. To guarantee the original mappers
2645 * reliability, unmap the page from child processes. The child
2646 * may get SIGKILLed if it later faults.
2648 if (outside_reserve) {
2649 BUG_ON(huge_pte_none(pte));
2650 if (unmap_ref_private(mm, vma, old_page, address)) {
2651 BUG_ON(huge_pte_none(pte));
2653 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2654 if (likely(pte_same(huge_ptep_get(ptep), pte)))
2655 goto retry_avoidcopy;
2657 * race occurs while re-acquiring page table
2658 * lock, and our job is done.
2665 /* Caller expects lock to be held */
2668 return VM_FAULT_OOM;
2670 return VM_FAULT_SIGBUS;
2674 * When the original hugepage is shared one, it does not have
2675 * anon_vma prepared.
2677 if (unlikely(anon_vma_prepare(vma))) {
2678 page_cache_release(new_page);
2679 page_cache_release(old_page);
2680 /* Caller expects lock to be held */
2682 return VM_FAULT_OOM;
2685 copy_user_huge_page(new_page, old_page, address, vma,
2686 pages_per_huge_page(h));
2687 __SetPageUptodate(new_page);
2689 mmun_start = address & huge_page_mask(h);
2690 mmun_end = mmun_start + huge_page_size(h);
2691 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2693 * Retake the page table lock to check for racing updates
2694 * before the page tables are altered
2697 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2698 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2699 ClearPagePrivate(new_page);
2702 huge_ptep_clear_flush(vma, address, ptep);
2703 set_huge_pte_at(mm, address, ptep,
2704 make_huge_pte(vma, new_page, 1));
2705 page_remove_rmap(old_page);
2706 hugepage_add_new_anon_rmap(new_page, vma, address);
2707 /* Make the old page be freed below */
2708 new_page = old_page;
2711 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2712 page_cache_release(new_page);
2713 page_cache_release(old_page);
2715 /* Caller expects lock to be held */
2720 /* Return the pagecache page at a given address within a VMA */
2721 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2722 struct vm_area_struct *vma, unsigned long address)
2724 struct address_space *mapping;
2727 mapping = vma->vm_file->f_mapping;
2728 idx = vma_hugecache_offset(h, vma, address);
2730 return find_lock_page(mapping, idx);
2734 * Return whether there is a pagecache page to back given address within VMA.
2735 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2737 static bool hugetlbfs_pagecache_present(struct hstate *h,
2738 struct vm_area_struct *vma, unsigned long address)
2740 struct address_space *mapping;
2744 mapping = vma->vm_file->f_mapping;
2745 idx = vma_hugecache_offset(h, vma, address);
2747 page = find_get_page(mapping, idx);
2750 return page != NULL;
2753 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2754 unsigned long address, pte_t *ptep, unsigned int flags)
2756 struct hstate *h = hstate_vma(vma);
2757 int ret = VM_FAULT_SIGBUS;
2762 struct address_space *mapping;
2767 * Currently, we are forced to kill the process in the event the
2768 * original mapper has unmapped pages from the child due to a failed
2769 * COW. Warn that such a situation has occurred as it may not be obvious
2771 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2772 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2777 mapping = vma->vm_file->f_mapping;
2778 idx = vma_hugecache_offset(h, vma, address);
2781 * Use page lock to guard against racing truncation
2782 * before we get page_table_lock.
2785 page = find_lock_page(mapping, idx);
2787 size = i_size_read(mapping->host) >> huge_page_shift(h);
2790 page = alloc_huge_page(vma, address, 0);
2792 ret = PTR_ERR(page);
2796 ret = VM_FAULT_SIGBUS;
2799 clear_huge_page(page, address, pages_per_huge_page(h));
2800 __SetPageUptodate(page);
2802 if (vma->vm_flags & VM_MAYSHARE) {
2804 struct inode *inode = mapping->host;
2806 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2813 ClearPagePrivate(page);
2815 spin_lock(&inode->i_lock);
2816 inode->i_blocks += blocks_per_huge_page(h);
2817 spin_unlock(&inode->i_lock);
2820 if (unlikely(anon_vma_prepare(vma))) {
2822 goto backout_unlocked;
2828 * If memory error occurs between mmap() and fault, some process
2829 * don't have hwpoisoned swap entry for errored virtual address.
2830 * So we need to block hugepage fault by PG_hwpoison bit check.
2832 if (unlikely(PageHWPoison(page))) {
2833 ret = VM_FAULT_HWPOISON |
2834 VM_FAULT_SET_HINDEX(hstate_index(h));
2835 goto backout_unlocked;
2840 * If we are going to COW a private mapping later, we examine the
2841 * pending reservations for this page now. This will ensure that
2842 * any allocations necessary to record that reservation occur outside
2845 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2846 if (vma_needs_reservation(h, vma, address) < 0) {
2848 goto backout_unlocked;
2851 ptl = huge_pte_lockptr(h, mm, ptep);
2853 size = i_size_read(mapping->host) >> huge_page_shift(h);
2858 if (!huge_pte_none(huge_ptep_get(ptep)))
2862 ClearPagePrivate(page);
2863 hugepage_add_new_anon_rmap(page, vma, address);
2866 page_dup_rmap(page);
2867 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2868 && (vma->vm_flags & VM_SHARED)));
2869 set_huge_pte_at(mm, address, ptep, new_pte);
2871 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2872 /* Optimization, do the COW without a second fault */
2873 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
2889 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2890 unsigned long address, unsigned int flags)
2896 struct page *page = NULL;
2897 struct page *pagecache_page = NULL;
2898 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2899 struct hstate *h = hstate_vma(vma);
2901 address &= huge_page_mask(h);
2903 ptep = huge_pte_offset(mm, address);
2905 entry = huge_ptep_get(ptep);
2906 if (unlikely(is_hugetlb_entry_migration(entry))) {
2907 migration_entry_wait_huge(vma, mm, ptep);
2909 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2910 return VM_FAULT_HWPOISON_LARGE |
2911 VM_FAULT_SET_HINDEX(hstate_index(h));
2914 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2916 return VM_FAULT_OOM;
2919 * Serialize hugepage allocation and instantiation, so that we don't
2920 * get spurious allocation failures if two CPUs race to instantiate
2921 * the same page in the page cache.
2923 mutex_lock(&hugetlb_instantiation_mutex);
2924 entry = huge_ptep_get(ptep);
2925 if (huge_pte_none(entry)) {
2926 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2933 * If we are going to COW the mapping later, we examine the pending
2934 * reservations for this page now. This will ensure that any
2935 * allocations necessary to record that reservation occur outside the
2936 * spinlock. For private mappings, we also lookup the pagecache
2937 * page now as it is used to determine if a reservation has been
2940 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
2941 if (vma_needs_reservation(h, vma, address) < 0) {
2946 if (!(vma->vm_flags & VM_MAYSHARE))
2947 pagecache_page = hugetlbfs_pagecache_page(h,
2952 * hugetlb_cow() requires page locks of pte_page(entry) and
2953 * pagecache_page, so here we need take the former one
2954 * when page != pagecache_page or !pagecache_page.
2955 * Note that locking order is always pagecache_page -> page,
2956 * so no worry about deadlock.
2958 page = pte_page(entry);
2960 if (page != pagecache_page)
2963 ptl = huge_pte_lockptr(h, mm, ptep);
2965 /* Check for a racing update before calling hugetlb_cow */
2966 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2970 if (flags & FAULT_FLAG_WRITE) {
2971 if (!huge_pte_write(entry)) {
2972 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2973 pagecache_page, ptl);
2976 entry = huge_pte_mkdirty(entry);
2978 entry = pte_mkyoung(entry);
2979 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2980 flags & FAULT_FLAG_WRITE))
2981 update_mmu_cache(vma, address, ptep);
2986 if (pagecache_page) {
2987 unlock_page(pagecache_page);
2988 put_page(pagecache_page);
2990 if (page != pagecache_page)
2995 mutex_unlock(&hugetlb_instantiation_mutex);
3000 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3001 struct page **pages, struct vm_area_struct **vmas,
3002 unsigned long *position, unsigned long *nr_pages,
3003 long i, unsigned int flags)
3005 unsigned long pfn_offset;
3006 unsigned long vaddr = *position;
3007 unsigned long remainder = *nr_pages;
3008 struct hstate *h = hstate_vma(vma);
3010 while (vaddr < vma->vm_end && remainder) {
3012 spinlock_t *ptl = NULL;
3017 * Some archs (sparc64, sh*) have multiple pte_ts to
3018 * each hugepage. We have to make sure we get the
3019 * first, for the page indexing below to work.
3021 * Note that page table lock is not held when pte is null.
3023 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3025 ptl = huge_pte_lock(h, mm, pte);
3026 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3029 * When coredumping, it suits get_dump_page if we just return
3030 * an error where there's an empty slot with no huge pagecache
3031 * to back it. This way, we avoid allocating a hugepage, and
3032 * the sparse dumpfile avoids allocating disk blocks, but its
3033 * huge holes still show up with zeroes where they need to be.
3035 if (absent && (flags & FOLL_DUMP) &&
3036 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3044 * We need call hugetlb_fault for both hugepages under migration
3045 * (in which case hugetlb_fault waits for the migration,) and
3046 * hwpoisoned hugepages (in which case we need to prevent the
3047 * caller from accessing to them.) In order to do this, we use
3048 * here is_swap_pte instead of is_hugetlb_entry_migration and
3049 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3050 * both cases, and because we can't follow correct pages
3051 * directly from any kind of swap entries.
3053 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3054 ((flags & FOLL_WRITE) &&
3055 !huge_pte_write(huge_ptep_get(pte)))) {
3060 ret = hugetlb_fault(mm, vma, vaddr,
3061 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3062 if (!(ret & VM_FAULT_ERROR))
3069 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3070 page = pte_page(huge_ptep_get(pte));
3073 pages[i] = mem_map_offset(page, pfn_offset);
3074 get_page_foll(pages[i]);
3084 if (vaddr < vma->vm_end && remainder &&
3085 pfn_offset < pages_per_huge_page(h)) {
3087 * We use pfn_offset to avoid touching the pageframes
3088 * of this compound page.
3094 *nr_pages = remainder;
3097 return i ? i : -EFAULT;
3100 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3101 unsigned long address, unsigned long end, pgprot_t newprot)
3103 struct mm_struct *mm = vma->vm_mm;
3104 unsigned long start = address;
3107 struct hstate *h = hstate_vma(vma);
3108 unsigned long pages = 0;
3110 BUG_ON(address >= end);
3111 flush_cache_range(vma, address, end);
3113 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3114 for (; address < end; address += huge_page_size(h)) {
3116 ptep = huge_pte_offset(mm, address);
3119 ptl = huge_pte_lock(h, mm, ptep);
3120 if (huge_pmd_unshare(mm, &address, ptep)) {
3125 if (!huge_pte_none(huge_ptep_get(ptep))) {
3126 pte = huge_ptep_get_and_clear(mm, address, ptep);
3127 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3128 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3129 set_huge_pte_at(mm, address, ptep, pte);
3135 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3136 * may have cleared our pud entry and done put_page on the page table:
3137 * once we release i_mmap_mutex, another task can do the final put_page
3138 * and that page table be reused and filled with junk.
3140 flush_tlb_range(vma, start, end);
3141 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3143 return pages << h->order;
3146 int hugetlb_reserve_pages(struct inode *inode,
3148 struct vm_area_struct *vma,
3149 vm_flags_t vm_flags)
3152 struct hstate *h = hstate_inode(inode);
3153 struct hugepage_subpool *spool = subpool_inode(inode);
3156 * Only apply hugepage reservation if asked. At fault time, an
3157 * attempt will be made for VM_NORESERVE to allocate a page
3158 * without using reserves
3160 if (vm_flags & VM_NORESERVE)
3164 * Shared mappings base their reservation on the number of pages that
3165 * are already allocated on behalf of the file. Private mappings need
3166 * to reserve the full area even if read-only as mprotect() may be
3167 * called to make the mapping read-write. Assume !vma is a shm mapping
3169 if (!vma || vma->vm_flags & VM_MAYSHARE)
3170 chg = region_chg(&inode->i_mapping->private_list, from, to);
3172 struct resv_map *resv_map = resv_map_alloc();
3178 set_vma_resv_map(vma, resv_map);
3179 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3187 /* There must be enough pages in the subpool for the mapping */
3188 if (hugepage_subpool_get_pages(spool, chg)) {
3194 * Check enough hugepages are available for the reservation.
3195 * Hand the pages back to the subpool if there are not
3197 ret = hugetlb_acct_memory(h, chg);
3199 hugepage_subpool_put_pages(spool, chg);
3204 * Account for the reservations made. Shared mappings record regions
3205 * that have reservations as they are shared by multiple VMAs.
3206 * When the last VMA disappears, the region map says how much
3207 * the reservation was and the page cache tells how much of
3208 * the reservation was consumed. Private mappings are per-VMA and
3209 * only the consumed reservations are tracked. When the VMA
3210 * disappears, the original reservation is the VMA size and the
3211 * consumed reservations are stored in the map. Hence, nothing
3212 * else has to be done for private mappings here
3214 if (!vma || vma->vm_flags & VM_MAYSHARE)
3215 region_add(&inode->i_mapping->private_list, from, to);
3223 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3225 struct hstate *h = hstate_inode(inode);
3226 long chg = region_truncate(&inode->i_mapping->private_list, offset);
3227 struct hugepage_subpool *spool = subpool_inode(inode);
3229 spin_lock(&inode->i_lock);
3230 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3231 spin_unlock(&inode->i_lock);
3233 hugepage_subpool_put_pages(spool, (chg - freed));
3234 hugetlb_acct_memory(h, -(chg - freed));
3237 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3238 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3239 struct vm_area_struct *vma,
3240 unsigned long addr, pgoff_t idx)
3242 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3244 unsigned long sbase = saddr & PUD_MASK;
3245 unsigned long s_end = sbase + PUD_SIZE;
3247 /* Allow segments to share if only one is marked locked */
3248 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3249 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3252 * match the virtual addresses, permission and the alignment of the
3255 if (pmd_index(addr) != pmd_index(saddr) ||
3256 vm_flags != svm_flags ||
3257 sbase < svma->vm_start || svma->vm_end < s_end)
3263 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3265 unsigned long base = addr & PUD_MASK;
3266 unsigned long end = base + PUD_SIZE;
3269 * check on proper vm_flags and page table alignment
3271 if (vma->vm_flags & VM_MAYSHARE &&
3272 vma->vm_start <= base && end <= vma->vm_end)
3278 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3279 * and returns the corresponding pte. While this is not necessary for the
3280 * !shared pmd case because we can allocate the pmd later as well, it makes the
3281 * code much cleaner. pmd allocation is essential for the shared case because
3282 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3283 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3284 * bad pmd for sharing.
3286 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3288 struct vm_area_struct *vma = find_vma(mm, addr);
3289 struct address_space *mapping = vma->vm_file->f_mapping;
3290 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3292 struct vm_area_struct *svma;
3293 unsigned long saddr;
3298 if (!vma_shareable(vma, addr))
3299 return (pte_t *)pmd_alloc(mm, pud, addr);
3301 mutex_lock(&mapping->i_mmap_mutex);
3302 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3306 saddr = page_table_shareable(svma, vma, addr, idx);
3308 spte = huge_pte_offset(svma->vm_mm, saddr);
3310 get_page(virt_to_page(spte));
3319 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3322 pud_populate(mm, pud,
3323 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3325 put_page(virt_to_page(spte));
3328 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3329 mutex_unlock(&mapping->i_mmap_mutex);
3334 * unmap huge page backed by shared pte.
3336 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3337 * indicated by page_count > 1, unmap is achieved by clearing pud and
3338 * decrementing the ref count. If count == 1, the pte page is not shared.
3340 * called with page table lock held.
3342 * returns: 1 successfully unmapped a shared pte page
3343 * 0 the underlying pte page is not shared, or it is the last user
3345 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3347 pgd_t *pgd = pgd_offset(mm, *addr);
3348 pud_t *pud = pud_offset(pgd, *addr);
3350 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3351 if (page_count(virt_to_page(ptep)) == 1)
3355 put_page(virt_to_page(ptep));
3356 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3359 #define want_pmd_share() (1)
3360 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3361 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3365 #define want_pmd_share() (0)
3366 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3368 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3369 pte_t *huge_pte_alloc(struct mm_struct *mm,
3370 unsigned long addr, unsigned long sz)
3376 pgd = pgd_offset(mm, addr);
3377 pud = pud_alloc(mm, pgd, addr);
3379 if (sz == PUD_SIZE) {
3382 BUG_ON(sz != PMD_SIZE);
3383 if (want_pmd_share() && pud_none(*pud))
3384 pte = huge_pmd_share(mm, addr, pud);
3386 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3389 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3394 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3400 pgd = pgd_offset(mm, addr);
3401 if (pgd_present(*pgd)) {
3402 pud = pud_offset(pgd, addr);
3403 if (pud_present(*pud)) {
3405 return (pte_t *)pud;
3406 pmd = pmd_offset(pud, addr);
3409 return (pte_t *) pmd;
3413 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3414 pmd_t *pmd, int write)
3418 page = pte_page(*(pte_t *)pmd);
3420 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3425 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3426 pud_t *pud, int write)
3430 page = pte_page(*(pte_t *)pud);
3432 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3436 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3438 /* Can be overriden by architectures */
3439 __attribute__((weak)) struct page *
3440 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3441 pud_t *pud, int write)
3447 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3449 #ifdef CONFIG_MEMORY_FAILURE
3451 /* Should be called in hugetlb_lock */
3452 static int is_hugepage_on_freelist(struct page *hpage)
3456 struct hstate *h = page_hstate(hpage);
3457 int nid = page_to_nid(hpage);
3459 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3466 * This function is called from memory failure code.
3467 * Assume the caller holds page lock of the head page.
3469 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3471 struct hstate *h = page_hstate(hpage);
3472 int nid = page_to_nid(hpage);
3475 spin_lock(&hugetlb_lock);
3476 if (is_hugepage_on_freelist(hpage)) {
3478 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3479 * but dangling hpage->lru can trigger list-debug warnings
3480 * (this happens when we call unpoison_memory() on it),
3481 * so let it point to itself with list_del_init().
3483 list_del_init(&hpage->lru);
3484 set_page_refcounted(hpage);
3485 h->free_huge_pages--;
3486 h->free_huge_pages_node[nid]--;
3489 spin_unlock(&hugetlb_lock);
3494 bool isolate_huge_page(struct page *page, struct list_head *list)
3496 VM_BUG_ON(!PageHead(page));
3497 if (!get_page_unless_zero(page))
3499 spin_lock(&hugetlb_lock);
3500 list_move_tail(&page->lru, list);
3501 spin_unlock(&hugetlb_lock);
3505 void putback_active_hugepage(struct page *page)
3507 VM_BUG_ON(!PageHead(page));
3508 spin_lock(&hugetlb_lock);
3509 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3510 spin_unlock(&hugetlb_lock);
3514 bool is_hugepage_active(struct page *page)
3516 VM_BUG_ON(!PageHuge(page));
3518 * This function can be called for a tail page because the caller,
3519 * scan_movable_pages, scans through a given pfn-range which typically
3520 * covers one memory block. In systems using gigantic hugepage (1GB
3521 * for x86_64,) a hugepage is larger than a memory block, and we don't
3522 * support migrating such large hugepages for now, so return false
3523 * when called for tail pages.
3528 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3529 * so we should return false for them.
3531 if (unlikely(PageHWPoison(page)))
3533 return page_count(page) > 0;