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 copy_gigantic_page(struct page *dst, struct page *src)
482 struct hstate *h = page_hstate(src);
483 struct page *dst_base = dst;
484 struct page *src_base = src;
486 for (i = 0; i < pages_per_huge_page(h); ) {
488 copy_highpage(dst, src);
491 dst = mem_map_next(dst, dst_base, i);
492 src = mem_map_next(src, src_base, i);
496 void copy_huge_page(struct page *dst, struct page *src)
499 struct hstate *h = page_hstate(src);
501 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
502 copy_gigantic_page(dst, src);
507 for (i = 0; i < pages_per_huge_page(h); i++) {
509 copy_highpage(dst + i, src + i);
513 static void enqueue_huge_page(struct hstate *h, struct page *page)
515 int nid = page_to_nid(page);
516 list_move(&page->lru, &h->hugepage_freelists[nid]);
517 h->free_huge_pages++;
518 h->free_huge_pages_node[nid]++;
521 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
525 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
526 if (!is_migrate_isolate_page(page))
529 * if 'non-isolated free hugepage' not found on the list,
530 * the allocation fails.
532 if (&h->hugepage_freelists[nid] == &page->lru)
534 list_move(&page->lru, &h->hugepage_activelist);
535 set_page_refcounted(page);
536 h->free_huge_pages--;
537 h->free_huge_pages_node[nid]--;
541 /* Movability of hugepages depends on migration support. */
542 static inline gfp_t htlb_alloc_mask(struct hstate *h)
544 if (hugepages_treat_as_movable || hugepage_migration_support(h))
545 return GFP_HIGHUSER_MOVABLE;
550 static struct page *dequeue_huge_page_vma(struct hstate *h,
551 struct vm_area_struct *vma,
552 unsigned long address, int avoid_reserve,
555 struct page *page = NULL;
556 struct mempolicy *mpol;
557 nodemask_t *nodemask;
558 struct zonelist *zonelist;
561 unsigned int cpuset_mems_cookie;
564 * A child process with MAP_PRIVATE mappings created by their parent
565 * have no page reserves. This check ensures that reservations are
566 * not "stolen". The child may still get SIGKILLed
568 if (!vma_has_reserves(vma, chg) &&
569 h->free_huge_pages - h->resv_huge_pages == 0)
572 /* If reserves cannot be used, ensure enough pages are in the pool */
573 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
577 cpuset_mems_cookie = get_mems_allowed();
578 zonelist = huge_zonelist(vma, address,
579 htlb_alloc_mask(h), &mpol, &nodemask);
581 for_each_zone_zonelist_nodemask(zone, z, zonelist,
582 MAX_NR_ZONES - 1, nodemask) {
583 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) {
584 page = dequeue_huge_page_node(h, zone_to_nid(zone));
588 if (!vma_has_reserves(vma, chg))
591 SetPagePrivate(page);
592 h->resv_huge_pages--;
599 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
607 static void update_and_free_page(struct hstate *h, struct page *page)
611 VM_BUG_ON(h->order >= MAX_ORDER);
614 h->nr_huge_pages_node[page_to_nid(page)]--;
615 for (i = 0; i < pages_per_huge_page(h); i++) {
616 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
617 1 << PG_referenced | 1 << PG_dirty |
618 1 << PG_active | 1 << PG_reserved |
619 1 << PG_private | 1 << PG_writeback);
621 VM_BUG_ON(hugetlb_cgroup_from_page(page));
622 set_compound_page_dtor(page, NULL);
623 set_page_refcounted(page);
624 arch_release_hugepage(page);
625 __free_pages(page, huge_page_order(h));
628 struct hstate *size_to_hstate(unsigned long size)
633 if (huge_page_size(h) == size)
639 static void free_huge_page(struct page *page)
642 * Can't pass hstate in here because it is called from the
643 * compound page destructor.
645 struct hstate *h = page_hstate(page);
646 int nid = page_to_nid(page);
647 struct hugepage_subpool *spool =
648 (struct hugepage_subpool *)page_private(page);
649 bool restore_reserve;
651 set_page_private(page, 0);
652 page->mapping = NULL;
653 BUG_ON(page_count(page));
654 BUG_ON(page_mapcount(page));
655 restore_reserve = PagePrivate(page);
656 ClearPagePrivate(page);
658 spin_lock(&hugetlb_lock);
659 hugetlb_cgroup_uncharge_page(hstate_index(h),
660 pages_per_huge_page(h), page);
662 h->resv_huge_pages++;
664 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
665 /* remove the page from active list */
666 list_del(&page->lru);
667 update_and_free_page(h, page);
668 h->surplus_huge_pages--;
669 h->surplus_huge_pages_node[nid]--;
671 arch_clear_hugepage_flags(page);
672 enqueue_huge_page(h, page);
674 spin_unlock(&hugetlb_lock);
675 hugepage_subpool_put_pages(spool, 1);
678 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
680 INIT_LIST_HEAD(&page->lru);
681 set_compound_page_dtor(page, free_huge_page);
682 spin_lock(&hugetlb_lock);
683 set_hugetlb_cgroup(page, NULL);
685 h->nr_huge_pages_node[nid]++;
686 spin_unlock(&hugetlb_lock);
687 put_page(page); /* free it into the hugepage allocator */
690 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
693 int nr_pages = 1 << order;
694 struct page *p = page + 1;
696 /* we rely on prep_new_huge_page to set the destructor */
697 set_compound_order(page, order);
699 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
701 set_page_count(p, 0);
702 p->first_page = page;
707 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
708 * transparent huge pages. See the PageTransHuge() documentation for more
711 int PageHuge(struct page *page)
713 compound_page_dtor *dtor;
715 if (!PageCompound(page))
718 page = compound_head(page);
719 dtor = get_compound_page_dtor(page);
721 return dtor == free_huge_page;
723 EXPORT_SYMBOL_GPL(PageHuge);
725 pgoff_t __basepage_index(struct page *page)
727 struct page *page_head = compound_head(page);
728 pgoff_t index = page_index(page_head);
729 unsigned long compound_idx;
731 if (!PageHuge(page_head))
732 return page_index(page);
734 if (compound_order(page_head) >= MAX_ORDER)
735 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
737 compound_idx = page - page_head;
739 return (index << compound_order(page_head)) + compound_idx;
742 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
746 if (h->order >= MAX_ORDER)
749 page = alloc_pages_exact_node(nid,
750 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
751 __GFP_REPEAT|__GFP_NOWARN,
754 if (arch_prepare_hugepage(page)) {
755 __free_pages(page, huge_page_order(h));
758 prep_new_huge_page(h, page, nid);
765 * common helper functions for hstate_next_node_to_{alloc|free}.
766 * We may have allocated or freed a huge page based on a different
767 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
768 * be outside of *nodes_allowed. Ensure that we use an allowed
769 * node for alloc or free.
771 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
773 nid = next_node(nid, *nodes_allowed);
774 if (nid == MAX_NUMNODES)
775 nid = first_node(*nodes_allowed);
776 VM_BUG_ON(nid >= MAX_NUMNODES);
781 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
783 if (!node_isset(nid, *nodes_allowed))
784 nid = next_node_allowed(nid, nodes_allowed);
789 * returns the previously saved node ["this node"] from which to
790 * allocate a persistent huge page for the pool and advance the
791 * next node from which to allocate, handling wrap at end of node
794 static int hstate_next_node_to_alloc(struct hstate *h,
795 nodemask_t *nodes_allowed)
799 VM_BUG_ON(!nodes_allowed);
801 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
802 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
808 * helper for free_pool_huge_page() - return the previously saved
809 * node ["this node"] from which to free a huge page. Advance the
810 * next node id whether or not we find a free huge page to free so
811 * that the next attempt to free addresses the next node.
813 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
817 VM_BUG_ON(!nodes_allowed);
819 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
820 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
825 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
826 for (nr_nodes = nodes_weight(*mask); \
828 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
831 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
832 for (nr_nodes = nodes_weight(*mask); \
834 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
837 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
843 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
844 page = alloc_fresh_huge_page_node(h, node);
852 count_vm_event(HTLB_BUDDY_PGALLOC);
854 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
860 * Free huge page from pool from next node to free.
861 * Attempt to keep persistent huge pages more or less
862 * balanced over allowed nodes.
863 * Called with hugetlb_lock locked.
865 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
871 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
873 * If we're returning unused surplus pages, only examine
874 * nodes with surplus pages.
876 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
877 !list_empty(&h->hugepage_freelists[node])) {
879 list_entry(h->hugepage_freelists[node].next,
881 list_del(&page->lru);
882 h->free_huge_pages--;
883 h->free_huge_pages_node[node]--;
885 h->surplus_huge_pages--;
886 h->surplus_huge_pages_node[node]--;
888 update_and_free_page(h, page);
898 * Dissolve a given free hugepage into free buddy pages. This function does
899 * nothing for in-use (including surplus) hugepages.
901 static void dissolve_free_huge_page(struct page *page)
903 spin_lock(&hugetlb_lock);
904 if (PageHuge(page) && !page_count(page)) {
905 struct hstate *h = page_hstate(page);
906 int nid = page_to_nid(page);
907 list_del(&page->lru);
908 h->free_huge_pages--;
909 h->free_huge_pages_node[nid]--;
910 update_and_free_page(h, page);
912 spin_unlock(&hugetlb_lock);
916 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
917 * make specified memory blocks removable from the system.
918 * Note that start_pfn should aligned with (minimum) hugepage size.
920 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
922 unsigned int order = 8 * sizeof(void *);
926 /* Set scan step to minimum hugepage size */
928 if (order > huge_page_order(h))
929 order = huge_page_order(h);
930 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
931 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
932 dissolve_free_huge_page(pfn_to_page(pfn));
935 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
940 if (h->order >= MAX_ORDER)
944 * Assume we will successfully allocate the surplus page to
945 * prevent racing processes from causing the surplus to exceed
948 * This however introduces a different race, where a process B
949 * tries to grow the static hugepage pool while alloc_pages() is
950 * called by process A. B will only examine the per-node
951 * counters in determining if surplus huge pages can be
952 * converted to normal huge pages in adjust_pool_surplus(). A
953 * won't be able to increment the per-node counter, until the
954 * lock is dropped by B, but B doesn't drop hugetlb_lock until
955 * no more huge pages can be converted from surplus to normal
956 * state (and doesn't try to convert again). Thus, we have a
957 * case where a surplus huge page exists, the pool is grown, and
958 * the surplus huge page still exists after, even though it
959 * should just have been converted to a normal huge page. This
960 * does not leak memory, though, as the hugepage will be freed
961 * once it is out of use. It also does not allow the counters to
962 * go out of whack in adjust_pool_surplus() as we don't modify
963 * the node values until we've gotten the hugepage and only the
964 * per-node value is checked there.
966 spin_lock(&hugetlb_lock);
967 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
968 spin_unlock(&hugetlb_lock);
972 h->surplus_huge_pages++;
974 spin_unlock(&hugetlb_lock);
976 if (nid == NUMA_NO_NODE)
977 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
978 __GFP_REPEAT|__GFP_NOWARN,
981 page = alloc_pages_exact_node(nid,
982 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
983 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
985 if (page && arch_prepare_hugepage(page)) {
986 __free_pages(page, huge_page_order(h));
990 spin_lock(&hugetlb_lock);
992 INIT_LIST_HEAD(&page->lru);
993 r_nid = page_to_nid(page);
994 set_compound_page_dtor(page, free_huge_page);
995 set_hugetlb_cgroup(page, NULL);
997 * We incremented the global counters already
999 h->nr_huge_pages_node[r_nid]++;
1000 h->surplus_huge_pages_node[r_nid]++;
1001 __count_vm_event(HTLB_BUDDY_PGALLOC);
1004 h->surplus_huge_pages--;
1005 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1007 spin_unlock(&hugetlb_lock);
1013 * This allocation function is useful in the context where vma is irrelevant.
1014 * E.g. soft-offlining uses this function because it only cares physical
1015 * address of error page.
1017 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1019 struct page *page = NULL;
1021 spin_lock(&hugetlb_lock);
1022 if (h->free_huge_pages - h->resv_huge_pages > 0)
1023 page = dequeue_huge_page_node(h, nid);
1024 spin_unlock(&hugetlb_lock);
1027 page = alloc_buddy_huge_page(h, nid);
1033 * Increase the hugetlb pool such that it can accommodate a reservation
1036 static int gather_surplus_pages(struct hstate *h, int delta)
1038 struct list_head surplus_list;
1039 struct page *page, *tmp;
1041 int needed, allocated;
1042 bool alloc_ok = true;
1044 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1046 h->resv_huge_pages += delta;
1051 INIT_LIST_HEAD(&surplus_list);
1055 spin_unlock(&hugetlb_lock);
1056 for (i = 0; i < needed; i++) {
1057 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1062 list_add(&page->lru, &surplus_list);
1067 * After retaking hugetlb_lock, we need to recalculate 'needed'
1068 * because either resv_huge_pages or free_huge_pages may have changed.
1070 spin_lock(&hugetlb_lock);
1071 needed = (h->resv_huge_pages + delta) -
1072 (h->free_huge_pages + allocated);
1077 * We were not able to allocate enough pages to
1078 * satisfy the entire reservation so we free what
1079 * we've allocated so far.
1084 * The surplus_list now contains _at_least_ the number of extra pages
1085 * needed to accommodate the reservation. Add the appropriate number
1086 * of pages to the hugetlb pool and free the extras back to the buddy
1087 * allocator. Commit the entire reservation here to prevent another
1088 * process from stealing the pages as they are added to the pool but
1089 * before they are reserved.
1091 needed += allocated;
1092 h->resv_huge_pages += delta;
1095 /* Free the needed pages to the hugetlb pool */
1096 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1100 * This page is now managed by the hugetlb allocator and has
1101 * no users -- drop the buddy allocator's reference.
1103 put_page_testzero(page);
1104 VM_BUG_ON(page_count(page));
1105 enqueue_huge_page(h, page);
1108 spin_unlock(&hugetlb_lock);
1110 /* Free unnecessary surplus pages to the buddy allocator */
1111 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1113 spin_lock(&hugetlb_lock);
1119 * When releasing a hugetlb pool reservation, any surplus pages that were
1120 * allocated to satisfy the reservation must be explicitly freed if they were
1122 * Called with hugetlb_lock held.
1124 static void return_unused_surplus_pages(struct hstate *h,
1125 unsigned long unused_resv_pages)
1127 unsigned long nr_pages;
1129 /* Uncommit the reservation */
1130 h->resv_huge_pages -= unused_resv_pages;
1132 /* Cannot return gigantic pages currently */
1133 if (h->order >= MAX_ORDER)
1136 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1139 * We want to release as many surplus pages as possible, spread
1140 * evenly across all nodes with memory. Iterate across these nodes
1141 * until we can no longer free unreserved surplus pages. This occurs
1142 * when the nodes with surplus pages have no free pages.
1143 * free_pool_huge_page() will balance the the freed pages across the
1144 * on-line nodes with memory and will handle the hstate accounting.
1146 while (nr_pages--) {
1147 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1153 * Determine if the huge page at addr within the vma has an associated
1154 * reservation. Where it does not we will need to logically increase
1155 * reservation and actually increase subpool usage before an allocation
1156 * can occur. Where any new reservation would be required the
1157 * reservation change is prepared, but not committed. Once the page
1158 * has been allocated from the subpool and instantiated the change should
1159 * be committed via vma_commit_reservation. No action is required on
1162 static long vma_needs_reservation(struct hstate *h,
1163 struct vm_area_struct *vma, unsigned long addr)
1165 struct address_space *mapping = vma->vm_file->f_mapping;
1166 struct inode *inode = mapping->host;
1168 if (vma->vm_flags & VM_MAYSHARE) {
1169 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1170 return region_chg(&inode->i_mapping->private_list,
1173 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1178 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1179 struct resv_map *resv = vma_resv_map(vma);
1181 err = region_chg(&resv->regions, idx, idx + 1);
1187 static void vma_commit_reservation(struct hstate *h,
1188 struct vm_area_struct *vma, unsigned long addr)
1190 struct address_space *mapping = vma->vm_file->f_mapping;
1191 struct inode *inode = mapping->host;
1193 if (vma->vm_flags & VM_MAYSHARE) {
1194 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1195 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1197 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1198 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1199 struct resv_map *resv = vma_resv_map(vma);
1201 /* Mark this page used in the map. */
1202 region_add(&resv->regions, idx, idx + 1);
1206 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1207 unsigned long addr, int avoid_reserve)
1209 struct hugepage_subpool *spool = subpool_vma(vma);
1210 struct hstate *h = hstate_vma(vma);
1214 struct hugetlb_cgroup *h_cg;
1216 idx = hstate_index(h);
1218 * Processes that did not create the mapping will have no
1219 * reserves and will not have accounted against subpool
1220 * limit. Check that the subpool limit can be made before
1221 * satisfying the allocation MAP_NORESERVE mappings may also
1222 * need pages and subpool limit allocated allocated if no reserve
1225 chg = vma_needs_reservation(h, vma, addr);
1227 return ERR_PTR(-ENOMEM);
1228 if (chg || avoid_reserve)
1229 if (hugepage_subpool_get_pages(spool, 1))
1230 return ERR_PTR(-ENOSPC);
1232 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1234 if (chg || avoid_reserve)
1235 hugepage_subpool_put_pages(spool, 1);
1236 return ERR_PTR(-ENOSPC);
1238 spin_lock(&hugetlb_lock);
1239 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1241 spin_unlock(&hugetlb_lock);
1242 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1244 hugetlb_cgroup_uncharge_cgroup(idx,
1245 pages_per_huge_page(h),
1247 if (chg || avoid_reserve)
1248 hugepage_subpool_put_pages(spool, 1);
1249 return ERR_PTR(-ENOSPC);
1251 spin_lock(&hugetlb_lock);
1252 list_move(&page->lru, &h->hugepage_activelist);
1255 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1256 spin_unlock(&hugetlb_lock);
1258 set_page_private(page, (unsigned long)spool);
1260 vma_commit_reservation(h, vma, addr);
1265 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1266 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1267 * where no ERR_VALUE is expected to be returned.
1269 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1270 unsigned long addr, int avoid_reserve)
1272 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1278 int __weak alloc_bootmem_huge_page(struct hstate *h)
1280 struct huge_bootmem_page *m;
1283 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1286 addr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
1287 huge_page_size(h), huge_page_size(h), 0);
1291 * Use the beginning of the huge page to store the
1292 * huge_bootmem_page struct (until gather_bootmem
1293 * puts them into the mem_map).
1302 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1303 /* Put them into a private list first because mem_map is not up yet */
1304 list_add(&m->list, &huge_boot_pages);
1309 static void prep_compound_huge_page(struct page *page, int order)
1311 if (unlikely(order > (MAX_ORDER - 1)))
1312 prep_compound_gigantic_page(page, order);
1314 prep_compound_page(page, order);
1317 /* Put bootmem huge pages into the standard lists after mem_map is up */
1318 static void __init gather_bootmem_prealloc(void)
1320 struct huge_bootmem_page *m;
1322 list_for_each_entry(m, &huge_boot_pages, list) {
1323 struct hstate *h = m->hstate;
1326 #ifdef CONFIG_HIGHMEM
1327 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1328 free_bootmem_late((unsigned long)m,
1329 sizeof(struct huge_bootmem_page));
1331 page = virt_to_page(m);
1333 __ClearPageReserved(page);
1334 WARN_ON(page_count(page) != 1);
1335 prep_compound_huge_page(page, h->order);
1336 prep_new_huge_page(h, page, page_to_nid(page));
1338 * If we had gigantic hugepages allocated at boot time, we need
1339 * to restore the 'stolen' pages to totalram_pages in order to
1340 * fix confusing memory reports from free(1) and another
1341 * side-effects, like CommitLimit going negative.
1343 if (h->order > (MAX_ORDER - 1))
1344 adjust_managed_page_count(page, 1 << h->order);
1348 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1352 for (i = 0; i < h->max_huge_pages; ++i) {
1353 if (h->order >= MAX_ORDER) {
1354 if (!alloc_bootmem_huge_page(h))
1356 } else if (!alloc_fresh_huge_page(h,
1357 &node_states[N_MEMORY]))
1360 h->max_huge_pages = i;
1363 static void __init hugetlb_init_hstates(void)
1367 for_each_hstate(h) {
1368 /* oversize hugepages were init'ed in early boot */
1369 if (h->order < MAX_ORDER)
1370 hugetlb_hstate_alloc_pages(h);
1374 static char * __init memfmt(char *buf, unsigned long n)
1376 if (n >= (1UL << 30))
1377 sprintf(buf, "%lu GB", n >> 30);
1378 else if (n >= (1UL << 20))
1379 sprintf(buf, "%lu MB", n >> 20);
1381 sprintf(buf, "%lu KB", n >> 10);
1385 static void __init report_hugepages(void)
1389 for_each_hstate(h) {
1391 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1392 memfmt(buf, huge_page_size(h)),
1393 h->free_huge_pages);
1397 #ifdef CONFIG_HIGHMEM
1398 static void try_to_free_low(struct hstate *h, unsigned long count,
1399 nodemask_t *nodes_allowed)
1403 if (h->order >= MAX_ORDER)
1406 for_each_node_mask(i, *nodes_allowed) {
1407 struct page *page, *next;
1408 struct list_head *freel = &h->hugepage_freelists[i];
1409 list_for_each_entry_safe(page, next, freel, lru) {
1410 if (count >= h->nr_huge_pages)
1412 if (PageHighMem(page))
1414 list_del(&page->lru);
1415 update_and_free_page(h, page);
1416 h->free_huge_pages--;
1417 h->free_huge_pages_node[page_to_nid(page)]--;
1422 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1423 nodemask_t *nodes_allowed)
1429 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1430 * balanced by operating on them in a round-robin fashion.
1431 * Returns 1 if an adjustment was made.
1433 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1438 VM_BUG_ON(delta != -1 && delta != 1);
1441 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1442 if (h->surplus_huge_pages_node[node])
1446 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1447 if (h->surplus_huge_pages_node[node] <
1448 h->nr_huge_pages_node[node])
1455 h->surplus_huge_pages += delta;
1456 h->surplus_huge_pages_node[node] += delta;
1460 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1461 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1462 nodemask_t *nodes_allowed)
1464 unsigned long min_count, ret;
1466 if (h->order >= MAX_ORDER)
1467 return h->max_huge_pages;
1470 * Increase the pool size
1471 * First take pages out of surplus state. Then make up the
1472 * remaining difference by allocating fresh huge pages.
1474 * We might race with alloc_buddy_huge_page() here and be unable
1475 * to convert a surplus huge page to a normal huge page. That is
1476 * not critical, though, it just means the overall size of the
1477 * pool might be one hugepage larger than it needs to be, but
1478 * within all the constraints specified by the sysctls.
1480 spin_lock(&hugetlb_lock);
1481 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1482 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1486 while (count > persistent_huge_pages(h)) {
1488 * If this allocation races such that we no longer need the
1489 * page, free_huge_page will handle it by freeing the page
1490 * and reducing the surplus.
1492 spin_unlock(&hugetlb_lock);
1493 ret = alloc_fresh_huge_page(h, nodes_allowed);
1494 spin_lock(&hugetlb_lock);
1498 /* Bail for signals. Probably ctrl-c from user */
1499 if (signal_pending(current))
1504 * Decrease the pool size
1505 * First return free pages to the buddy allocator (being careful
1506 * to keep enough around to satisfy reservations). Then place
1507 * pages into surplus state as needed so the pool will shrink
1508 * to the desired size as pages become free.
1510 * By placing pages into the surplus state independent of the
1511 * overcommit value, we are allowing the surplus pool size to
1512 * exceed overcommit. There are few sane options here. Since
1513 * alloc_buddy_huge_page() is checking the global counter,
1514 * though, we'll note that we're not allowed to exceed surplus
1515 * and won't grow the pool anywhere else. Not until one of the
1516 * sysctls are changed, or the surplus pages go out of use.
1518 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1519 min_count = max(count, min_count);
1520 try_to_free_low(h, min_count, nodes_allowed);
1521 while (min_count < persistent_huge_pages(h)) {
1522 if (!free_pool_huge_page(h, nodes_allowed, 0))
1525 while (count < persistent_huge_pages(h)) {
1526 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1530 ret = persistent_huge_pages(h);
1531 spin_unlock(&hugetlb_lock);
1535 #define HSTATE_ATTR_RO(_name) \
1536 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1538 #define HSTATE_ATTR(_name) \
1539 static struct kobj_attribute _name##_attr = \
1540 __ATTR(_name, 0644, _name##_show, _name##_store)
1542 static struct kobject *hugepages_kobj;
1543 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1545 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1547 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1551 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1552 if (hstate_kobjs[i] == kobj) {
1554 *nidp = NUMA_NO_NODE;
1558 return kobj_to_node_hstate(kobj, nidp);
1561 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1562 struct kobj_attribute *attr, char *buf)
1565 unsigned long nr_huge_pages;
1568 h = kobj_to_hstate(kobj, &nid);
1569 if (nid == NUMA_NO_NODE)
1570 nr_huge_pages = h->nr_huge_pages;
1572 nr_huge_pages = h->nr_huge_pages_node[nid];
1574 return sprintf(buf, "%lu\n", nr_huge_pages);
1577 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1578 struct kobject *kobj, struct kobj_attribute *attr,
1579 const char *buf, size_t len)
1583 unsigned long count;
1585 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1587 err = kstrtoul(buf, 10, &count);
1591 h = kobj_to_hstate(kobj, &nid);
1592 if (h->order >= MAX_ORDER) {
1597 if (nid == NUMA_NO_NODE) {
1599 * global hstate attribute
1601 if (!(obey_mempolicy &&
1602 init_nodemask_of_mempolicy(nodes_allowed))) {
1603 NODEMASK_FREE(nodes_allowed);
1604 nodes_allowed = &node_states[N_MEMORY];
1606 } else if (nodes_allowed) {
1608 * per node hstate attribute: adjust count to global,
1609 * but restrict alloc/free to the specified node.
1611 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1612 init_nodemask_of_node(nodes_allowed, nid);
1614 nodes_allowed = &node_states[N_MEMORY];
1616 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1618 if (nodes_allowed != &node_states[N_MEMORY])
1619 NODEMASK_FREE(nodes_allowed);
1623 NODEMASK_FREE(nodes_allowed);
1627 static ssize_t nr_hugepages_show(struct kobject *kobj,
1628 struct kobj_attribute *attr, char *buf)
1630 return nr_hugepages_show_common(kobj, attr, buf);
1633 static ssize_t nr_hugepages_store(struct kobject *kobj,
1634 struct kobj_attribute *attr, const char *buf, size_t len)
1636 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1638 HSTATE_ATTR(nr_hugepages);
1643 * hstate attribute for optionally mempolicy-based constraint on persistent
1644 * huge page alloc/free.
1646 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1647 struct kobj_attribute *attr, char *buf)
1649 return nr_hugepages_show_common(kobj, attr, buf);
1652 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1653 struct kobj_attribute *attr, const char *buf, size_t len)
1655 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1657 HSTATE_ATTR(nr_hugepages_mempolicy);
1661 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1662 struct kobj_attribute *attr, char *buf)
1664 struct hstate *h = kobj_to_hstate(kobj, NULL);
1665 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1668 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1669 struct kobj_attribute *attr, const char *buf, size_t count)
1672 unsigned long input;
1673 struct hstate *h = kobj_to_hstate(kobj, NULL);
1675 if (h->order >= MAX_ORDER)
1678 err = kstrtoul(buf, 10, &input);
1682 spin_lock(&hugetlb_lock);
1683 h->nr_overcommit_huge_pages = input;
1684 spin_unlock(&hugetlb_lock);
1688 HSTATE_ATTR(nr_overcommit_hugepages);
1690 static ssize_t free_hugepages_show(struct kobject *kobj,
1691 struct kobj_attribute *attr, char *buf)
1694 unsigned long free_huge_pages;
1697 h = kobj_to_hstate(kobj, &nid);
1698 if (nid == NUMA_NO_NODE)
1699 free_huge_pages = h->free_huge_pages;
1701 free_huge_pages = h->free_huge_pages_node[nid];
1703 return sprintf(buf, "%lu\n", free_huge_pages);
1705 HSTATE_ATTR_RO(free_hugepages);
1707 static ssize_t resv_hugepages_show(struct kobject *kobj,
1708 struct kobj_attribute *attr, char *buf)
1710 struct hstate *h = kobj_to_hstate(kobj, NULL);
1711 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1713 HSTATE_ATTR_RO(resv_hugepages);
1715 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1716 struct kobj_attribute *attr, char *buf)
1719 unsigned long surplus_huge_pages;
1722 h = kobj_to_hstate(kobj, &nid);
1723 if (nid == NUMA_NO_NODE)
1724 surplus_huge_pages = h->surplus_huge_pages;
1726 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1728 return sprintf(buf, "%lu\n", surplus_huge_pages);
1730 HSTATE_ATTR_RO(surplus_hugepages);
1732 static struct attribute *hstate_attrs[] = {
1733 &nr_hugepages_attr.attr,
1734 &nr_overcommit_hugepages_attr.attr,
1735 &free_hugepages_attr.attr,
1736 &resv_hugepages_attr.attr,
1737 &surplus_hugepages_attr.attr,
1739 &nr_hugepages_mempolicy_attr.attr,
1744 static struct attribute_group hstate_attr_group = {
1745 .attrs = hstate_attrs,
1748 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1749 struct kobject **hstate_kobjs,
1750 struct attribute_group *hstate_attr_group)
1753 int hi = hstate_index(h);
1755 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1756 if (!hstate_kobjs[hi])
1759 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1761 kobject_put(hstate_kobjs[hi]);
1766 static void __init hugetlb_sysfs_init(void)
1771 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1772 if (!hugepages_kobj)
1775 for_each_hstate(h) {
1776 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1777 hstate_kobjs, &hstate_attr_group);
1779 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1786 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1787 * with node devices in node_devices[] using a parallel array. The array
1788 * index of a node device or _hstate == node id.
1789 * This is here to avoid any static dependency of the node device driver, in
1790 * the base kernel, on the hugetlb module.
1792 struct node_hstate {
1793 struct kobject *hugepages_kobj;
1794 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1796 struct node_hstate node_hstates[MAX_NUMNODES];
1799 * A subset of global hstate attributes for node devices
1801 static struct attribute *per_node_hstate_attrs[] = {
1802 &nr_hugepages_attr.attr,
1803 &free_hugepages_attr.attr,
1804 &surplus_hugepages_attr.attr,
1808 static struct attribute_group per_node_hstate_attr_group = {
1809 .attrs = per_node_hstate_attrs,
1813 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1814 * Returns node id via non-NULL nidp.
1816 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1820 for (nid = 0; nid < nr_node_ids; nid++) {
1821 struct node_hstate *nhs = &node_hstates[nid];
1823 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1824 if (nhs->hstate_kobjs[i] == kobj) {
1836 * Unregister hstate attributes from a single node device.
1837 * No-op if no hstate attributes attached.
1839 static void hugetlb_unregister_node(struct node *node)
1842 struct node_hstate *nhs = &node_hstates[node->dev.id];
1844 if (!nhs->hugepages_kobj)
1845 return; /* no hstate attributes */
1847 for_each_hstate(h) {
1848 int idx = hstate_index(h);
1849 if (nhs->hstate_kobjs[idx]) {
1850 kobject_put(nhs->hstate_kobjs[idx]);
1851 nhs->hstate_kobjs[idx] = NULL;
1855 kobject_put(nhs->hugepages_kobj);
1856 nhs->hugepages_kobj = NULL;
1860 * hugetlb module exit: unregister hstate attributes from node devices
1863 static void hugetlb_unregister_all_nodes(void)
1868 * disable node device registrations.
1870 register_hugetlbfs_with_node(NULL, NULL);
1873 * remove hstate attributes from any nodes that have them.
1875 for (nid = 0; nid < nr_node_ids; nid++)
1876 hugetlb_unregister_node(node_devices[nid]);
1880 * Register hstate attributes for a single node device.
1881 * No-op if attributes already registered.
1883 static void hugetlb_register_node(struct node *node)
1886 struct node_hstate *nhs = &node_hstates[node->dev.id];
1889 if (nhs->hugepages_kobj)
1890 return; /* already allocated */
1892 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1894 if (!nhs->hugepages_kobj)
1897 for_each_hstate(h) {
1898 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1900 &per_node_hstate_attr_group);
1902 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1903 h->name, node->dev.id);
1904 hugetlb_unregister_node(node);
1911 * hugetlb init time: register hstate attributes for all registered node
1912 * devices of nodes that have memory. All on-line nodes should have
1913 * registered their associated device by this time.
1915 static void hugetlb_register_all_nodes(void)
1919 for_each_node_state(nid, N_MEMORY) {
1920 struct node *node = node_devices[nid];
1921 if (node->dev.id == nid)
1922 hugetlb_register_node(node);
1926 * Let the node device driver know we're here so it can
1927 * [un]register hstate attributes on node hotplug.
1929 register_hugetlbfs_with_node(hugetlb_register_node,
1930 hugetlb_unregister_node);
1932 #else /* !CONFIG_NUMA */
1934 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1942 static void hugetlb_unregister_all_nodes(void) { }
1944 static void hugetlb_register_all_nodes(void) { }
1948 static void __exit hugetlb_exit(void)
1952 hugetlb_unregister_all_nodes();
1954 for_each_hstate(h) {
1955 kobject_put(hstate_kobjs[hstate_index(h)]);
1958 kobject_put(hugepages_kobj);
1960 module_exit(hugetlb_exit);
1962 static int __init hugetlb_init(void)
1964 /* Some platform decide whether they support huge pages at boot
1965 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1966 * there is no such support
1968 if (HPAGE_SHIFT == 0)
1971 if (!size_to_hstate(default_hstate_size)) {
1972 default_hstate_size = HPAGE_SIZE;
1973 if (!size_to_hstate(default_hstate_size))
1974 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1976 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1977 if (default_hstate_max_huge_pages)
1978 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1980 hugetlb_init_hstates();
1981 gather_bootmem_prealloc();
1984 hugetlb_sysfs_init();
1985 hugetlb_register_all_nodes();
1986 hugetlb_cgroup_file_init();
1990 module_init(hugetlb_init);
1992 /* Should be called on processing a hugepagesz=... option */
1993 void __init hugetlb_add_hstate(unsigned order)
1998 if (size_to_hstate(PAGE_SIZE << order)) {
1999 pr_warning("hugepagesz= specified twice, ignoring\n");
2002 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2004 h = &hstates[hugetlb_max_hstate++];
2006 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2007 h->nr_huge_pages = 0;
2008 h->free_huge_pages = 0;
2009 for (i = 0; i < MAX_NUMNODES; ++i)
2010 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2011 INIT_LIST_HEAD(&h->hugepage_activelist);
2012 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2013 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2014 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2015 huge_page_size(h)/1024);
2020 static int __init hugetlb_nrpages_setup(char *s)
2023 static unsigned long *last_mhp;
2026 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2027 * so this hugepages= parameter goes to the "default hstate".
2029 if (!hugetlb_max_hstate)
2030 mhp = &default_hstate_max_huge_pages;
2032 mhp = &parsed_hstate->max_huge_pages;
2034 if (mhp == last_mhp) {
2035 pr_warning("hugepages= specified twice without "
2036 "interleaving hugepagesz=, ignoring\n");
2040 if (sscanf(s, "%lu", mhp) <= 0)
2044 * Global state is always initialized later in hugetlb_init.
2045 * But we need to allocate >= MAX_ORDER hstates here early to still
2046 * use the bootmem allocator.
2048 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2049 hugetlb_hstate_alloc_pages(parsed_hstate);
2055 __setup("hugepages=", hugetlb_nrpages_setup);
2057 static int __init hugetlb_default_setup(char *s)
2059 default_hstate_size = memparse(s, &s);
2062 __setup("default_hugepagesz=", hugetlb_default_setup);
2064 static unsigned int cpuset_mems_nr(unsigned int *array)
2067 unsigned int nr = 0;
2069 for_each_node_mask(node, cpuset_current_mems_allowed)
2075 #ifdef CONFIG_SYSCTL
2076 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2077 struct ctl_table *table, int write,
2078 void __user *buffer, size_t *length, loff_t *ppos)
2080 struct hstate *h = &default_hstate;
2084 tmp = h->max_huge_pages;
2086 if (write && h->order >= MAX_ORDER)
2090 table->maxlen = sizeof(unsigned long);
2091 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2096 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2097 GFP_KERNEL | __GFP_NORETRY);
2098 if (!(obey_mempolicy &&
2099 init_nodemask_of_mempolicy(nodes_allowed))) {
2100 NODEMASK_FREE(nodes_allowed);
2101 nodes_allowed = &node_states[N_MEMORY];
2103 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2105 if (nodes_allowed != &node_states[N_MEMORY])
2106 NODEMASK_FREE(nodes_allowed);
2112 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2113 void __user *buffer, size_t *length, loff_t *ppos)
2116 return hugetlb_sysctl_handler_common(false, table, write,
2117 buffer, length, ppos);
2121 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2122 void __user *buffer, size_t *length, loff_t *ppos)
2124 return hugetlb_sysctl_handler_common(true, table, write,
2125 buffer, length, ppos);
2127 #endif /* CONFIG_NUMA */
2129 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2130 void __user *buffer,
2131 size_t *length, loff_t *ppos)
2133 struct hstate *h = &default_hstate;
2137 tmp = h->nr_overcommit_huge_pages;
2139 if (write && h->order >= MAX_ORDER)
2143 table->maxlen = sizeof(unsigned long);
2144 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2149 spin_lock(&hugetlb_lock);
2150 h->nr_overcommit_huge_pages = tmp;
2151 spin_unlock(&hugetlb_lock);
2157 #endif /* CONFIG_SYSCTL */
2159 void hugetlb_report_meminfo(struct seq_file *m)
2161 struct hstate *h = &default_hstate;
2163 "HugePages_Total: %5lu\n"
2164 "HugePages_Free: %5lu\n"
2165 "HugePages_Rsvd: %5lu\n"
2166 "HugePages_Surp: %5lu\n"
2167 "Hugepagesize: %8lu kB\n",
2171 h->surplus_huge_pages,
2172 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2175 int hugetlb_report_node_meminfo(int nid, char *buf)
2177 struct hstate *h = &default_hstate;
2179 "Node %d HugePages_Total: %5u\n"
2180 "Node %d HugePages_Free: %5u\n"
2181 "Node %d HugePages_Surp: %5u\n",
2182 nid, h->nr_huge_pages_node[nid],
2183 nid, h->free_huge_pages_node[nid],
2184 nid, h->surplus_huge_pages_node[nid]);
2187 void hugetlb_show_meminfo(void)
2192 for_each_node_state(nid, N_MEMORY)
2194 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2196 h->nr_huge_pages_node[nid],
2197 h->free_huge_pages_node[nid],
2198 h->surplus_huge_pages_node[nid],
2199 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2202 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2203 unsigned long hugetlb_total_pages(void)
2206 unsigned long nr_total_pages = 0;
2209 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2210 return nr_total_pages;
2213 static int hugetlb_acct_memory(struct hstate *h, long delta)
2217 spin_lock(&hugetlb_lock);
2219 * When cpuset is configured, it breaks the strict hugetlb page
2220 * reservation as the accounting is done on a global variable. Such
2221 * reservation is completely rubbish in the presence of cpuset because
2222 * the reservation is not checked against page availability for the
2223 * current cpuset. Application can still potentially OOM'ed by kernel
2224 * with lack of free htlb page in cpuset that the task is in.
2225 * Attempt to enforce strict accounting with cpuset is almost
2226 * impossible (or too ugly) because cpuset is too fluid that
2227 * task or memory node can be dynamically moved between cpusets.
2229 * The change of semantics for shared hugetlb mapping with cpuset is
2230 * undesirable. However, in order to preserve some of the semantics,
2231 * we fall back to check against current free page availability as
2232 * a best attempt and hopefully to minimize the impact of changing
2233 * semantics that cpuset has.
2236 if (gather_surplus_pages(h, delta) < 0)
2239 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2240 return_unused_surplus_pages(h, delta);
2247 return_unused_surplus_pages(h, (unsigned long) -delta);
2250 spin_unlock(&hugetlb_lock);
2254 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2256 struct resv_map *resv = vma_resv_map(vma);
2259 * This new VMA should share its siblings reservation map if present.
2260 * The VMA will only ever have a valid reservation map pointer where
2261 * it is being copied for another still existing VMA. As that VMA
2262 * has a reference to the reservation map it cannot disappear until
2263 * after this open call completes. It is therefore safe to take a
2264 * new reference here without additional locking.
2267 kref_get(&resv->refs);
2270 static void resv_map_put(struct vm_area_struct *vma)
2272 struct resv_map *resv = vma_resv_map(vma);
2276 kref_put(&resv->refs, resv_map_release);
2279 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2281 struct hstate *h = hstate_vma(vma);
2282 struct resv_map *resv = vma_resv_map(vma);
2283 struct hugepage_subpool *spool = subpool_vma(vma);
2284 unsigned long reserve;
2285 unsigned long start;
2289 start = vma_hugecache_offset(h, vma, vma->vm_start);
2290 end = vma_hugecache_offset(h, vma, vma->vm_end);
2292 reserve = (end - start) -
2293 region_count(&resv->regions, start, end);
2298 hugetlb_acct_memory(h, -reserve);
2299 hugepage_subpool_put_pages(spool, reserve);
2305 * We cannot handle pagefaults against hugetlb pages at all. They cause
2306 * handle_mm_fault() to try to instantiate regular-sized pages in the
2307 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2310 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2316 const struct vm_operations_struct hugetlb_vm_ops = {
2317 .fault = hugetlb_vm_op_fault,
2318 .open = hugetlb_vm_op_open,
2319 .close = hugetlb_vm_op_close,
2322 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2328 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2329 vma->vm_page_prot)));
2331 entry = huge_pte_wrprotect(mk_huge_pte(page,
2332 vma->vm_page_prot));
2334 entry = pte_mkyoung(entry);
2335 entry = pte_mkhuge(entry);
2336 entry = arch_make_huge_pte(entry, vma, page, writable);
2341 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2342 unsigned long address, pte_t *ptep)
2346 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2347 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2348 update_mmu_cache(vma, address, ptep);
2352 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2353 struct vm_area_struct *vma)
2355 pte_t *src_pte, *dst_pte, entry;
2356 struct page *ptepage;
2359 struct hstate *h = hstate_vma(vma);
2360 unsigned long sz = huge_page_size(h);
2362 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2364 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2365 src_pte = huge_pte_offset(src, addr);
2368 dst_pte = huge_pte_alloc(dst, addr, sz);
2372 /* If the pagetables are shared don't copy or take references */
2373 if (dst_pte == src_pte)
2376 spin_lock(&dst->page_table_lock);
2377 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2378 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2380 huge_ptep_set_wrprotect(src, addr, src_pte);
2381 entry = huge_ptep_get(src_pte);
2382 ptepage = pte_page(entry);
2384 page_dup_rmap(ptepage);
2385 set_huge_pte_at(dst, addr, dst_pte, entry);
2387 spin_unlock(&src->page_table_lock);
2388 spin_unlock(&dst->page_table_lock);
2396 static int is_hugetlb_entry_migration(pte_t pte)
2400 if (huge_pte_none(pte) || pte_present(pte))
2402 swp = pte_to_swp_entry(pte);
2403 if (non_swap_entry(swp) && is_migration_entry(swp))
2409 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2413 if (huge_pte_none(pte) || pte_present(pte))
2415 swp = pte_to_swp_entry(pte);
2416 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2422 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2423 unsigned long start, unsigned long end,
2424 struct page *ref_page)
2426 int force_flush = 0;
2427 struct mm_struct *mm = vma->vm_mm;
2428 unsigned long address;
2432 struct hstate *h = hstate_vma(vma);
2433 unsigned long sz = huge_page_size(h);
2434 const unsigned long mmun_start = start; /* For mmu_notifiers */
2435 const unsigned long mmun_end = end; /* For mmu_notifiers */
2437 WARN_ON(!is_vm_hugetlb_page(vma));
2438 BUG_ON(start & ~huge_page_mask(h));
2439 BUG_ON(end & ~huge_page_mask(h));
2441 tlb_start_vma(tlb, vma);
2442 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2444 spin_lock(&mm->page_table_lock);
2445 for (address = start; address < end; address += sz) {
2446 ptep = huge_pte_offset(mm, address);
2450 if (huge_pmd_unshare(mm, &address, ptep))
2453 pte = huge_ptep_get(ptep);
2454 if (huge_pte_none(pte))
2458 * HWPoisoned hugepage is already unmapped and dropped reference
2460 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2461 huge_pte_clear(mm, address, ptep);
2465 page = pte_page(pte);
2467 * If a reference page is supplied, it is because a specific
2468 * page is being unmapped, not a range. Ensure the page we
2469 * are about to unmap is the actual page of interest.
2472 if (page != ref_page)
2476 * Mark the VMA as having unmapped its page so that
2477 * future faults in this VMA will fail rather than
2478 * looking like data was lost
2480 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2483 pte = huge_ptep_get_and_clear(mm, address, ptep);
2484 tlb_remove_tlb_entry(tlb, ptep, address);
2485 if (huge_pte_dirty(pte))
2486 set_page_dirty(page);
2488 page_remove_rmap(page);
2489 force_flush = !__tlb_remove_page(tlb, page);
2492 /* Bail out after unmapping reference page if supplied */
2496 spin_unlock(&mm->page_table_lock);
2498 * mmu_gather ran out of room to batch pages, we break out of
2499 * the PTE lock to avoid doing the potential expensive TLB invalidate
2500 * and page-free while holding it.
2505 if (address < end && !ref_page)
2508 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2509 tlb_end_vma(tlb, vma);
2512 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2513 struct vm_area_struct *vma, unsigned long start,
2514 unsigned long end, struct page *ref_page)
2516 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2519 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2520 * test will fail on a vma being torn down, and not grab a page table
2521 * on its way out. We're lucky that the flag has such an appropriate
2522 * name, and can in fact be safely cleared here. We could clear it
2523 * before the __unmap_hugepage_range above, but all that's necessary
2524 * is to clear it before releasing the i_mmap_mutex. This works
2525 * because in the context this is called, the VMA is about to be
2526 * destroyed and the i_mmap_mutex is held.
2528 vma->vm_flags &= ~VM_MAYSHARE;
2531 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2532 unsigned long end, struct page *ref_page)
2534 struct mm_struct *mm;
2535 struct mmu_gather tlb;
2539 tlb_gather_mmu(&tlb, mm, start, end);
2540 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2541 tlb_finish_mmu(&tlb, start, end);
2545 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2546 * mappping it owns the reserve page for. The intention is to unmap the page
2547 * from other VMAs and let the children be SIGKILLed if they are faulting the
2550 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2551 struct page *page, unsigned long address)
2553 struct hstate *h = hstate_vma(vma);
2554 struct vm_area_struct *iter_vma;
2555 struct address_space *mapping;
2559 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2560 * from page cache lookup which is in HPAGE_SIZE units.
2562 address = address & huge_page_mask(h);
2563 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2565 mapping = file_inode(vma->vm_file)->i_mapping;
2568 * Take the mapping lock for the duration of the table walk. As
2569 * this mapping should be shared between all the VMAs,
2570 * __unmap_hugepage_range() is called as the lock is already held
2572 mutex_lock(&mapping->i_mmap_mutex);
2573 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2574 /* Do not unmap the current VMA */
2575 if (iter_vma == vma)
2579 * Unmap the page from other VMAs without their own reserves.
2580 * They get marked to be SIGKILLed if they fault in these
2581 * areas. This is because a future no-page fault on this VMA
2582 * could insert a zeroed page instead of the data existing
2583 * from the time of fork. This would look like data corruption
2585 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2586 unmap_hugepage_range(iter_vma, address,
2587 address + huge_page_size(h), page);
2589 mutex_unlock(&mapping->i_mmap_mutex);
2595 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2596 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2597 * cannot race with other handlers or page migration.
2598 * Keep the pte_same checks anyway to make transition from the mutex easier.
2600 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2601 unsigned long address, pte_t *ptep, pte_t pte,
2602 struct page *pagecache_page)
2604 struct hstate *h = hstate_vma(vma);
2605 struct page *old_page, *new_page;
2606 int outside_reserve = 0;
2607 unsigned long mmun_start; /* For mmu_notifiers */
2608 unsigned long mmun_end; /* For mmu_notifiers */
2610 old_page = pte_page(pte);
2613 /* If no-one else is actually using this page, avoid the copy
2614 * and just make the page writable */
2615 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2616 page_move_anon_rmap(old_page, vma, address);
2617 set_huge_ptep_writable(vma, address, ptep);
2622 * If the process that created a MAP_PRIVATE mapping is about to
2623 * perform a COW due to a shared page count, attempt to satisfy
2624 * the allocation without using the existing reserves. The pagecache
2625 * page is used to determine if the reserve at this address was
2626 * consumed or not. If reserves were used, a partial faulted mapping
2627 * at the time of fork() could consume its reserves on COW instead
2628 * of the full address range.
2630 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2631 old_page != pagecache_page)
2632 outside_reserve = 1;
2634 page_cache_get(old_page);
2636 /* Drop page_table_lock as buddy allocator may be called */
2637 spin_unlock(&mm->page_table_lock);
2638 new_page = alloc_huge_page(vma, address, outside_reserve);
2640 if (IS_ERR(new_page)) {
2641 long err = PTR_ERR(new_page);
2642 page_cache_release(old_page);
2645 * If a process owning a MAP_PRIVATE mapping fails to COW,
2646 * it is due to references held by a child and an insufficient
2647 * huge page pool. To guarantee the original mappers
2648 * reliability, unmap the page from child processes. The child
2649 * may get SIGKILLed if it later faults.
2651 if (outside_reserve) {
2652 BUG_ON(huge_pte_none(pte));
2653 if (unmap_ref_private(mm, vma, old_page, address)) {
2654 BUG_ON(huge_pte_none(pte));
2655 spin_lock(&mm->page_table_lock);
2656 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2657 if (likely(pte_same(huge_ptep_get(ptep), pte)))
2658 goto retry_avoidcopy;
2660 * race occurs while re-acquiring page_table_lock, and
2668 /* Caller expects lock to be held */
2669 spin_lock(&mm->page_table_lock);
2671 return VM_FAULT_OOM;
2673 return VM_FAULT_SIGBUS;
2677 * When the original hugepage is shared one, it does not have
2678 * anon_vma prepared.
2680 if (unlikely(anon_vma_prepare(vma))) {
2681 page_cache_release(new_page);
2682 page_cache_release(old_page);
2683 /* Caller expects lock to be held */
2684 spin_lock(&mm->page_table_lock);
2685 return VM_FAULT_OOM;
2688 copy_user_huge_page(new_page, old_page, address, vma,
2689 pages_per_huge_page(h));
2690 __SetPageUptodate(new_page);
2692 mmun_start = address & huge_page_mask(h);
2693 mmun_end = mmun_start + huge_page_size(h);
2694 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2696 * Retake the page_table_lock to check for racing updates
2697 * before the page tables are altered
2699 spin_lock(&mm->page_table_lock);
2700 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2701 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2702 ClearPagePrivate(new_page);
2705 huge_ptep_clear_flush(vma, address, ptep);
2706 set_huge_pte_at(mm, address, ptep,
2707 make_huge_pte(vma, new_page, 1));
2708 page_remove_rmap(old_page);
2709 hugepage_add_new_anon_rmap(new_page, vma, address);
2710 /* Make the old page be freed below */
2711 new_page = old_page;
2713 spin_unlock(&mm->page_table_lock);
2714 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2715 page_cache_release(new_page);
2716 page_cache_release(old_page);
2718 /* Caller expects lock to be held */
2719 spin_lock(&mm->page_table_lock);
2723 /* Return the pagecache page at a given address within a VMA */
2724 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2725 struct vm_area_struct *vma, unsigned long address)
2727 struct address_space *mapping;
2730 mapping = vma->vm_file->f_mapping;
2731 idx = vma_hugecache_offset(h, vma, address);
2733 return find_lock_page(mapping, idx);
2737 * Return whether there is a pagecache page to back given address within VMA.
2738 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2740 static bool hugetlbfs_pagecache_present(struct hstate *h,
2741 struct vm_area_struct *vma, unsigned long address)
2743 struct address_space *mapping;
2747 mapping = vma->vm_file->f_mapping;
2748 idx = vma_hugecache_offset(h, vma, address);
2750 page = find_get_page(mapping, idx);
2753 return page != NULL;
2756 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2757 unsigned long address, pte_t *ptep, unsigned int flags)
2759 struct hstate *h = hstate_vma(vma);
2760 int ret = VM_FAULT_SIGBUS;
2765 struct address_space *mapping;
2769 * Currently, we are forced to kill the process in the event the
2770 * original mapper has unmapped pages from the child due to a failed
2771 * COW. Warn that such a situation has occurred as it may not be obvious
2773 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2774 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2779 mapping = vma->vm_file->f_mapping;
2780 idx = vma_hugecache_offset(h, vma, address);
2783 * Use page lock to guard against racing truncation
2784 * before we get page_table_lock.
2787 page = find_lock_page(mapping, idx);
2789 size = i_size_read(mapping->host) >> huge_page_shift(h);
2792 page = alloc_huge_page(vma, address, 0);
2794 ret = PTR_ERR(page);
2798 ret = VM_FAULT_SIGBUS;
2801 clear_huge_page(page, address, pages_per_huge_page(h));
2802 __SetPageUptodate(page);
2804 if (vma->vm_flags & VM_MAYSHARE) {
2806 struct inode *inode = mapping->host;
2808 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2815 ClearPagePrivate(page);
2817 spin_lock(&inode->i_lock);
2818 inode->i_blocks += blocks_per_huge_page(h);
2819 spin_unlock(&inode->i_lock);
2822 if (unlikely(anon_vma_prepare(vma))) {
2824 goto backout_unlocked;
2830 * If memory error occurs between mmap() and fault, some process
2831 * don't have hwpoisoned swap entry for errored virtual address.
2832 * So we need to block hugepage fault by PG_hwpoison bit check.
2834 if (unlikely(PageHWPoison(page))) {
2835 ret = VM_FAULT_HWPOISON |
2836 VM_FAULT_SET_HINDEX(hstate_index(h));
2837 goto backout_unlocked;
2842 * If we are going to COW a private mapping later, we examine the
2843 * pending reservations for this page now. This will ensure that
2844 * any allocations necessary to record that reservation occur outside
2847 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2848 if (vma_needs_reservation(h, vma, address) < 0) {
2850 goto backout_unlocked;
2853 spin_lock(&mm->page_table_lock);
2854 size = i_size_read(mapping->host) >> huge_page_shift(h);
2859 if (!huge_pte_none(huge_ptep_get(ptep)))
2863 ClearPagePrivate(page);
2864 hugepage_add_new_anon_rmap(page, vma, address);
2867 page_dup_rmap(page);
2868 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2869 && (vma->vm_flags & VM_SHARED)));
2870 set_huge_pte_at(mm, address, ptep, new_pte);
2872 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2873 /* Optimization, do the COW without a second fault */
2874 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2877 spin_unlock(&mm->page_table_lock);
2883 spin_unlock(&mm->page_table_lock);
2890 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2891 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(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 spin_lock(&mm->page_table_lock);
2964 /* Check for a racing update before calling hugetlb_cow */
2965 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2966 goto out_page_table_lock;
2969 if (flags & FAULT_FLAG_WRITE) {
2970 if (!huge_pte_write(entry)) {
2971 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2973 goto out_page_table_lock;
2975 entry = huge_pte_mkdirty(entry);
2977 entry = pte_mkyoung(entry);
2978 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2979 flags & FAULT_FLAG_WRITE))
2980 update_mmu_cache(vma, address, ptep);
2982 out_page_table_lock:
2983 spin_unlock(&mm->page_table_lock);
2985 if (pagecache_page) {
2986 unlock_page(pagecache_page);
2987 put_page(pagecache_page);
2989 if (page != pagecache_page)
2994 mutex_unlock(&hugetlb_instantiation_mutex);
2999 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3000 struct page **pages, struct vm_area_struct **vmas,
3001 unsigned long *position, unsigned long *nr_pages,
3002 long i, unsigned int flags)
3004 unsigned long pfn_offset;
3005 unsigned long vaddr = *position;
3006 unsigned long remainder = *nr_pages;
3007 struct hstate *h = hstate_vma(vma);
3009 spin_lock(&mm->page_table_lock);
3010 while (vaddr < vma->vm_end && remainder) {
3016 * Some archs (sparc64, sh*) have multiple pte_ts to
3017 * each hugepage. We have to make sure we get the
3018 * first, for the page indexing below to work.
3020 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3021 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3024 * When coredumping, it suits get_dump_page if we just return
3025 * an error where there's an empty slot with no huge pagecache
3026 * to back it. This way, we avoid allocating a hugepage, and
3027 * the sparse dumpfile avoids allocating disk blocks, but its
3028 * huge holes still show up with zeroes where they need to be.
3030 if (absent && (flags & FOLL_DUMP) &&
3031 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3037 * We need call hugetlb_fault for both hugepages under migration
3038 * (in which case hugetlb_fault waits for the migration,) and
3039 * hwpoisoned hugepages (in which case we need to prevent the
3040 * caller from accessing to them.) In order to do this, we use
3041 * here is_swap_pte instead of is_hugetlb_entry_migration and
3042 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3043 * both cases, and because we can't follow correct pages
3044 * directly from any kind of swap entries.
3046 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3047 ((flags & FOLL_WRITE) &&
3048 !huge_pte_write(huge_ptep_get(pte)))) {
3051 spin_unlock(&mm->page_table_lock);
3052 ret = hugetlb_fault(mm, vma, vaddr,
3053 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3054 spin_lock(&mm->page_table_lock);
3055 if (!(ret & VM_FAULT_ERROR))
3062 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3063 page = pte_page(huge_ptep_get(pte));
3066 pages[i] = mem_map_offset(page, pfn_offset);
3077 if (vaddr < vma->vm_end && remainder &&
3078 pfn_offset < pages_per_huge_page(h)) {
3080 * We use pfn_offset to avoid touching the pageframes
3081 * of this compound page.
3086 spin_unlock(&mm->page_table_lock);
3087 *nr_pages = remainder;
3090 return i ? i : -EFAULT;
3093 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3094 unsigned long address, unsigned long end, pgprot_t newprot)
3096 struct mm_struct *mm = vma->vm_mm;
3097 unsigned long start = address;
3100 struct hstate *h = hstate_vma(vma);
3101 unsigned long pages = 0;
3103 BUG_ON(address >= end);
3104 flush_cache_range(vma, address, end);
3106 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3107 spin_lock(&mm->page_table_lock);
3108 for (; address < end; address += huge_page_size(h)) {
3109 ptep = huge_pte_offset(mm, address);
3112 if (huge_pmd_unshare(mm, &address, ptep)) {
3116 if (!huge_pte_none(huge_ptep_get(ptep))) {
3117 pte = huge_ptep_get_and_clear(mm, address, ptep);
3118 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3119 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3120 set_huge_pte_at(mm, address, ptep, pte);
3124 spin_unlock(&mm->page_table_lock);
3126 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3127 * may have cleared our pud entry and done put_page on the page table:
3128 * once we release i_mmap_mutex, another task can do the final put_page
3129 * and that page table be reused and filled with junk.
3131 flush_tlb_range(vma, start, end);
3132 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3134 return pages << h->order;
3137 int hugetlb_reserve_pages(struct inode *inode,
3139 struct vm_area_struct *vma,
3140 vm_flags_t vm_flags)
3143 struct hstate *h = hstate_inode(inode);
3144 struct hugepage_subpool *spool = subpool_inode(inode);
3147 * Only apply hugepage reservation if asked. At fault time, an
3148 * attempt will be made for VM_NORESERVE to allocate a page
3149 * without using reserves
3151 if (vm_flags & VM_NORESERVE)
3155 * Shared mappings base their reservation on the number of pages that
3156 * are already allocated on behalf of the file. Private mappings need
3157 * to reserve the full area even if read-only as mprotect() may be
3158 * called to make the mapping read-write. Assume !vma is a shm mapping
3160 if (!vma || vma->vm_flags & VM_MAYSHARE)
3161 chg = region_chg(&inode->i_mapping->private_list, from, to);
3163 struct resv_map *resv_map = resv_map_alloc();
3169 set_vma_resv_map(vma, resv_map);
3170 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3178 /* There must be enough pages in the subpool for the mapping */
3179 if (hugepage_subpool_get_pages(spool, chg)) {
3185 * Check enough hugepages are available for the reservation.
3186 * Hand the pages back to the subpool if there are not
3188 ret = hugetlb_acct_memory(h, chg);
3190 hugepage_subpool_put_pages(spool, chg);
3195 * Account for the reservations made. Shared mappings record regions
3196 * that have reservations as they are shared by multiple VMAs.
3197 * When the last VMA disappears, the region map says how much
3198 * the reservation was and the page cache tells how much of
3199 * the reservation was consumed. Private mappings are per-VMA and
3200 * only the consumed reservations are tracked. When the VMA
3201 * disappears, the original reservation is the VMA size and the
3202 * consumed reservations are stored in the map. Hence, nothing
3203 * else has to be done for private mappings here
3205 if (!vma || vma->vm_flags & VM_MAYSHARE)
3206 region_add(&inode->i_mapping->private_list, from, to);
3214 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3216 struct hstate *h = hstate_inode(inode);
3217 long chg = region_truncate(&inode->i_mapping->private_list, offset);
3218 struct hugepage_subpool *spool = subpool_inode(inode);
3220 spin_lock(&inode->i_lock);
3221 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3222 spin_unlock(&inode->i_lock);
3224 hugepage_subpool_put_pages(spool, (chg - freed));
3225 hugetlb_acct_memory(h, -(chg - freed));
3228 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3229 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3230 struct vm_area_struct *vma,
3231 unsigned long addr, pgoff_t idx)
3233 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3235 unsigned long sbase = saddr & PUD_MASK;
3236 unsigned long s_end = sbase + PUD_SIZE;
3238 /* Allow segments to share if only one is marked locked */
3239 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3240 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3243 * match the virtual addresses, permission and the alignment of the
3246 if (pmd_index(addr) != pmd_index(saddr) ||
3247 vm_flags != svm_flags ||
3248 sbase < svma->vm_start || svma->vm_end < s_end)
3254 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3256 unsigned long base = addr & PUD_MASK;
3257 unsigned long end = base + PUD_SIZE;
3260 * check on proper vm_flags and page table alignment
3262 if (vma->vm_flags & VM_MAYSHARE &&
3263 vma->vm_start <= base && end <= vma->vm_end)
3269 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3270 * and returns the corresponding pte. While this is not necessary for the
3271 * !shared pmd case because we can allocate the pmd later as well, it makes the
3272 * code much cleaner. pmd allocation is essential for the shared case because
3273 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3274 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3275 * bad pmd for sharing.
3277 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3279 struct vm_area_struct *vma = find_vma(mm, addr);
3280 struct address_space *mapping = vma->vm_file->f_mapping;
3281 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3283 struct vm_area_struct *svma;
3284 unsigned long saddr;
3288 if (!vma_shareable(vma, addr))
3289 return (pte_t *)pmd_alloc(mm, pud, addr);
3291 mutex_lock(&mapping->i_mmap_mutex);
3292 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3296 saddr = page_table_shareable(svma, vma, addr, idx);
3298 spte = huge_pte_offset(svma->vm_mm, saddr);
3300 get_page(virt_to_page(spte));
3309 spin_lock(&mm->page_table_lock);
3311 pud_populate(mm, pud,
3312 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3314 put_page(virt_to_page(spte));
3315 spin_unlock(&mm->page_table_lock);
3317 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3318 mutex_unlock(&mapping->i_mmap_mutex);
3323 * unmap huge page backed by shared pte.
3325 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3326 * indicated by page_count > 1, unmap is achieved by clearing pud and
3327 * decrementing the ref count. If count == 1, the pte page is not shared.
3329 * called with vma->vm_mm->page_table_lock held.
3331 * returns: 1 successfully unmapped a shared pte page
3332 * 0 the underlying pte page is not shared, or it is the last user
3334 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3336 pgd_t *pgd = pgd_offset(mm, *addr);
3337 pud_t *pud = pud_offset(pgd, *addr);
3339 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3340 if (page_count(virt_to_page(ptep)) == 1)
3344 put_page(virt_to_page(ptep));
3345 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3348 #define want_pmd_share() (1)
3349 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3350 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3354 #define want_pmd_share() (0)
3355 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3357 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3358 pte_t *huge_pte_alloc(struct mm_struct *mm,
3359 unsigned long addr, unsigned long sz)
3365 pgd = pgd_offset(mm, addr);
3366 pud = pud_alloc(mm, pgd, addr);
3368 if (sz == PUD_SIZE) {
3371 BUG_ON(sz != PMD_SIZE);
3372 if (want_pmd_share() && pud_none(*pud))
3373 pte = huge_pmd_share(mm, addr, pud);
3375 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3378 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3383 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3389 pgd = pgd_offset(mm, addr);
3390 if (pgd_present(*pgd)) {
3391 pud = pud_offset(pgd, addr);
3392 if (pud_present(*pud)) {
3394 return (pte_t *)pud;
3395 pmd = pmd_offset(pud, addr);
3398 return (pte_t *) pmd;
3402 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3403 pmd_t *pmd, int write)
3407 page = pte_page(*(pte_t *)pmd);
3409 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3414 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3415 pud_t *pud, int write)
3419 page = pte_page(*(pte_t *)pud);
3421 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3425 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3427 /* Can be overriden by architectures */
3428 __attribute__((weak)) struct page *
3429 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3430 pud_t *pud, int write)
3436 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3438 #ifdef CONFIG_MEMORY_FAILURE
3440 /* Should be called in hugetlb_lock */
3441 static int is_hugepage_on_freelist(struct page *hpage)
3445 struct hstate *h = page_hstate(hpage);
3446 int nid = page_to_nid(hpage);
3448 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3455 * This function is called from memory failure code.
3456 * Assume the caller holds page lock of the head page.
3458 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3460 struct hstate *h = page_hstate(hpage);
3461 int nid = page_to_nid(hpage);
3464 spin_lock(&hugetlb_lock);
3465 if (is_hugepage_on_freelist(hpage)) {
3467 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3468 * but dangling hpage->lru can trigger list-debug warnings
3469 * (this happens when we call unpoison_memory() on it),
3470 * so let it point to itself with list_del_init().
3472 list_del_init(&hpage->lru);
3473 set_page_refcounted(hpage);
3474 h->free_huge_pages--;
3475 h->free_huge_pages_node[nid]--;
3478 spin_unlock(&hugetlb_lock);
3483 bool isolate_huge_page(struct page *page, struct list_head *list)
3485 VM_BUG_ON(!PageHead(page));
3486 if (!get_page_unless_zero(page))
3488 spin_lock(&hugetlb_lock);
3489 list_move_tail(&page->lru, list);
3490 spin_unlock(&hugetlb_lock);
3494 void putback_active_hugepage(struct page *page)
3496 VM_BUG_ON(!PageHead(page));
3497 spin_lock(&hugetlb_lock);
3498 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3499 spin_unlock(&hugetlb_lock);
3503 bool is_hugepage_active(struct page *page)
3505 VM_BUG_ON(!PageHuge(page));
3507 * This function can be called for a tail page because the caller,
3508 * scan_movable_pages, scans through a given pfn-range which typically
3509 * covers one memory block. In systems using gigantic hugepage (1GB
3510 * for x86_64,) a hugepage is larger than a memory block, and we don't
3511 * support migrating such large hugepages for now, so return false
3512 * when called for tail pages.
3517 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3518 * so we should return false for them.
3520 if (unlikely(PageHWPoison(page)))
3522 return page_count(page) > 0;