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 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
38 unsigned long hugepages_treat_as_movable;
40 int hugetlb_max_hstate __read_mostly;
41 unsigned int default_hstate_idx;
42 struct hstate hstates[HUGE_MAX_HSTATE];
44 __initdata LIST_HEAD(huge_boot_pages);
46 /* for command line parsing */
47 static struct hstate * __initdata parsed_hstate;
48 static unsigned long __initdata default_hstate_max_huge_pages;
49 static unsigned long __initdata default_hstate_size;
52 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
53 * free_huge_pages, and surplus_huge_pages.
55 DEFINE_SPINLOCK(hugetlb_lock);
57 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
59 bool free = (spool->count == 0) && (spool->used_hpages == 0);
61 spin_unlock(&spool->lock);
63 /* If no pages are used, and no other handles to the subpool
64 * remain, free the subpool the subpool remain */
69 struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
71 struct hugepage_subpool *spool;
73 spool = kmalloc(sizeof(*spool), GFP_KERNEL);
77 spin_lock_init(&spool->lock);
79 spool->max_hpages = nr_blocks;
80 spool->used_hpages = 0;
85 void hugepage_put_subpool(struct hugepage_subpool *spool)
87 spin_lock(&spool->lock);
88 BUG_ON(!spool->count);
90 unlock_or_release_subpool(spool);
93 static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
101 spin_lock(&spool->lock);
102 if ((spool->used_hpages + delta) <= spool->max_hpages) {
103 spool->used_hpages += delta;
107 spin_unlock(&spool->lock);
112 static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
118 spin_lock(&spool->lock);
119 spool->used_hpages -= delta;
120 /* If hugetlbfs_put_super couldn't free spool due to
121 * an outstanding quota reference, free it now. */
122 unlock_or_release_subpool(spool);
125 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
127 return HUGETLBFS_SB(inode->i_sb)->spool;
130 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
132 return subpool_inode(file_inode(vma->vm_file));
136 * Region tracking -- allows tracking of reservations and instantiated pages
137 * across the pages in a mapping.
139 * The region data structures are protected by a combination of the mmap_sem
140 * and the hugetlb_instantiation_mutex. To access or modify a region the caller
141 * must either hold the mmap_sem for write, or the mmap_sem for read and
142 * the hugetlb_instantiation_mutex:
144 * down_write(&mm->mmap_sem);
146 * down_read(&mm->mmap_sem);
147 * mutex_lock(&hugetlb_instantiation_mutex);
150 struct list_head link;
155 static long region_add(struct list_head *head, long f, long t)
157 struct file_region *rg, *nrg, *trg;
159 /* Locate the region we are either in or before. */
160 list_for_each_entry(rg, head, link)
164 /* Round our left edge to the current segment if it encloses us. */
168 /* Check for and consume any regions we now overlap with. */
170 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
171 if (&rg->link == head)
176 /* If this area reaches higher then extend our area to
177 * include it completely. If this is not the first area
178 * which we intend to reuse, free it. */
191 static long region_chg(struct list_head *head, long f, long t)
193 struct file_region *rg, *nrg;
196 /* Locate the region we are before or in. */
197 list_for_each_entry(rg, head, link)
201 /* If we are below the current region then a new region is required.
202 * Subtle, allocate a new region at the position but make it zero
203 * size such that we can guarantee to record the reservation. */
204 if (&rg->link == head || t < rg->from) {
205 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
210 INIT_LIST_HEAD(&nrg->link);
211 list_add(&nrg->link, rg->link.prev);
216 /* Round our left edge to the current segment if it encloses us. */
221 /* Check for and consume any regions we now overlap with. */
222 list_for_each_entry(rg, rg->link.prev, link) {
223 if (&rg->link == head)
228 /* We overlap with this area, if it extends further than
229 * us then we must extend ourselves. Account for its
230 * existing reservation. */
235 chg -= rg->to - rg->from;
240 static long region_truncate(struct list_head *head, long end)
242 struct file_region *rg, *trg;
245 /* Locate the region we are either in or before. */
246 list_for_each_entry(rg, head, link)
249 if (&rg->link == head)
252 /* If we are in the middle of a region then adjust it. */
253 if (end > rg->from) {
256 rg = list_entry(rg->link.next, typeof(*rg), link);
259 /* Drop any remaining regions. */
260 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
261 if (&rg->link == head)
263 chg += rg->to - rg->from;
270 static long region_count(struct list_head *head, long f, long t)
272 struct file_region *rg;
275 /* Locate each segment we overlap with, and count that overlap. */
276 list_for_each_entry(rg, head, link) {
285 seg_from = max(rg->from, f);
286 seg_to = min(rg->to, t);
288 chg += seg_to - seg_from;
295 * Convert the address within this vma to the page offset within
296 * the mapping, in pagecache page units; huge pages here.
298 static pgoff_t vma_hugecache_offset(struct hstate *h,
299 struct vm_area_struct *vma, unsigned long address)
301 return ((address - vma->vm_start) >> huge_page_shift(h)) +
302 (vma->vm_pgoff >> huge_page_order(h));
305 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
306 unsigned long address)
308 return vma_hugecache_offset(hstate_vma(vma), vma, address);
312 * Return the size of the pages allocated when backing a VMA. In the majority
313 * cases this will be same size as used by the page table entries.
315 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
317 struct hstate *hstate;
319 if (!is_vm_hugetlb_page(vma))
322 hstate = hstate_vma(vma);
324 return 1UL << huge_page_shift(hstate);
326 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
329 * Return the page size being used by the MMU to back a VMA. In the majority
330 * of cases, the page size used by the kernel matches the MMU size. On
331 * architectures where it differs, an architecture-specific version of this
332 * function is required.
334 #ifndef vma_mmu_pagesize
335 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
337 return vma_kernel_pagesize(vma);
342 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
343 * bits of the reservation map pointer, which are always clear due to
346 #define HPAGE_RESV_OWNER (1UL << 0)
347 #define HPAGE_RESV_UNMAPPED (1UL << 1)
348 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
351 * These helpers are used to track how many pages are reserved for
352 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
353 * is guaranteed to have their future faults succeed.
355 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
356 * the reserve counters are updated with the hugetlb_lock held. It is safe
357 * to reset the VMA at fork() time as it is not in use yet and there is no
358 * chance of the global counters getting corrupted as a result of the values.
360 * The private mapping reservation is represented in a subtly different
361 * manner to a shared mapping. A shared mapping has a region map associated
362 * with the underlying file, this region map represents the backing file
363 * pages which have ever had a reservation assigned which this persists even
364 * after the page is instantiated. A private mapping has a region map
365 * associated with the original mmap which is attached to all VMAs which
366 * reference it, this region map represents those offsets which have consumed
367 * reservation ie. where pages have been instantiated.
369 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
371 return (unsigned long)vma->vm_private_data;
374 static void set_vma_private_data(struct vm_area_struct *vma,
377 vma->vm_private_data = (void *)value;
382 struct list_head regions;
385 static struct resv_map *resv_map_alloc(void)
387 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
391 kref_init(&resv_map->refs);
392 INIT_LIST_HEAD(&resv_map->regions);
397 static void resv_map_release(struct kref *ref)
399 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
401 /* Clear out any active regions before we release the map. */
402 region_truncate(&resv_map->regions, 0);
406 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
408 VM_BUG_ON(!is_vm_hugetlb_page(vma));
409 if (!(vma->vm_flags & VM_MAYSHARE))
410 return (struct resv_map *)(get_vma_private_data(vma) &
415 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
417 VM_BUG_ON(!is_vm_hugetlb_page(vma));
418 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
420 set_vma_private_data(vma, (get_vma_private_data(vma) &
421 HPAGE_RESV_MASK) | (unsigned long)map);
424 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
426 VM_BUG_ON(!is_vm_hugetlb_page(vma));
427 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
429 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
432 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
434 VM_BUG_ON(!is_vm_hugetlb_page(vma));
436 return (get_vma_private_data(vma) & flag) != 0;
439 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
440 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
442 VM_BUG_ON(!is_vm_hugetlb_page(vma));
443 if (!(vma->vm_flags & VM_MAYSHARE))
444 vma->vm_private_data = (void *)0;
447 /* Returns true if the VMA has associated reserve pages */
448 static int vma_has_reserves(struct vm_area_struct *vma, long chg)
450 if (vma->vm_flags & VM_NORESERVE) {
452 * This address is already reserved by other process(chg == 0),
453 * so, we should decrement reserved count. Without decrementing,
454 * reserve count remains after releasing inode, because this
455 * allocated page will go into page cache and is regarded as
456 * coming from reserved pool in releasing step. Currently, we
457 * don't have any other solution to deal with this situation
458 * properly, so add work-around here.
460 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
466 /* Shared mappings always use reserves */
467 if (vma->vm_flags & VM_MAYSHARE)
471 * Only the process that called mmap() has reserves for
474 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
480 static void copy_gigantic_page(struct page *dst, struct page *src)
483 struct hstate *h = page_hstate(src);
484 struct page *dst_base = dst;
485 struct page *src_base = src;
487 for (i = 0; i < pages_per_huge_page(h); ) {
489 copy_highpage(dst, src);
492 dst = mem_map_next(dst, dst_base, i);
493 src = mem_map_next(src, src_base, i);
497 void copy_huge_page(struct page *dst, struct page *src)
500 struct hstate *h = page_hstate(src);
502 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
503 copy_gigantic_page(dst, src);
508 for (i = 0; i < pages_per_huge_page(h); i++) {
510 copy_highpage(dst + i, src + i);
514 static void enqueue_huge_page(struct hstate *h, struct page *page)
516 int nid = page_to_nid(page);
517 list_move(&page->lru, &h->hugepage_freelists[nid]);
518 h->free_huge_pages++;
519 h->free_huge_pages_node[nid]++;
522 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
526 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
527 if (!is_migrate_isolate_page(page))
530 * if 'non-isolated free hugepage' not found on the list,
531 * the allocation fails.
533 if (&h->hugepage_freelists[nid] == &page->lru)
535 list_move(&page->lru, &h->hugepage_activelist);
536 set_page_refcounted(page);
537 h->free_huge_pages--;
538 h->free_huge_pages_node[nid]--;
542 static struct page *dequeue_huge_page_vma(struct hstate *h,
543 struct vm_area_struct *vma,
544 unsigned long address, int avoid_reserve,
547 struct page *page = NULL;
548 struct mempolicy *mpol;
549 nodemask_t *nodemask;
550 struct zonelist *zonelist;
553 unsigned int cpuset_mems_cookie;
556 * A child process with MAP_PRIVATE mappings created by their parent
557 * have no page reserves. This check ensures that reservations are
558 * not "stolen". The child may still get SIGKILLed
560 if (!vma_has_reserves(vma, chg) &&
561 h->free_huge_pages - h->resv_huge_pages == 0)
564 /* If reserves cannot be used, ensure enough pages are in the pool */
565 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
569 cpuset_mems_cookie = get_mems_allowed();
570 zonelist = huge_zonelist(vma, address,
571 htlb_alloc_mask, &mpol, &nodemask);
573 for_each_zone_zonelist_nodemask(zone, z, zonelist,
574 MAX_NR_ZONES - 1, nodemask) {
575 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
576 page = dequeue_huge_page_node(h, zone_to_nid(zone));
580 if (!vma_has_reserves(vma, chg))
583 SetPagePrivate(page);
584 h->resv_huge_pages--;
591 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
599 static void update_and_free_page(struct hstate *h, struct page *page)
603 VM_BUG_ON(h->order >= MAX_ORDER);
606 h->nr_huge_pages_node[page_to_nid(page)]--;
607 for (i = 0; i < pages_per_huge_page(h); i++) {
608 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
609 1 << PG_referenced | 1 << PG_dirty |
610 1 << PG_active | 1 << PG_reserved |
611 1 << PG_private | 1 << PG_writeback);
613 VM_BUG_ON(hugetlb_cgroup_from_page(page));
614 set_compound_page_dtor(page, NULL);
615 set_page_refcounted(page);
616 arch_release_hugepage(page);
617 __free_pages(page, huge_page_order(h));
620 struct hstate *size_to_hstate(unsigned long size)
625 if (huge_page_size(h) == size)
631 static void free_huge_page(struct page *page)
634 * Can't pass hstate in here because it is called from the
635 * compound page destructor.
637 struct hstate *h = page_hstate(page);
638 int nid = page_to_nid(page);
639 struct hugepage_subpool *spool =
640 (struct hugepage_subpool *)page_private(page);
641 bool restore_reserve;
643 set_page_private(page, 0);
644 page->mapping = NULL;
645 BUG_ON(page_count(page));
646 BUG_ON(page_mapcount(page));
647 restore_reserve = PagePrivate(page);
649 spin_lock(&hugetlb_lock);
650 hugetlb_cgroup_uncharge_page(hstate_index(h),
651 pages_per_huge_page(h), page);
653 h->resv_huge_pages++;
655 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
656 /* remove the page from active list */
657 list_del(&page->lru);
658 update_and_free_page(h, page);
659 h->surplus_huge_pages--;
660 h->surplus_huge_pages_node[nid]--;
662 arch_clear_hugepage_flags(page);
663 enqueue_huge_page(h, page);
665 spin_unlock(&hugetlb_lock);
666 hugepage_subpool_put_pages(spool, 1);
669 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
671 INIT_LIST_HEAD(&page->lru);
672 set_compound_page_dtor(page, free_huge_page);
673 spin_lock(&hugetlb_lock);
674 set_hugetlb_cgroup(page, NULL);
676 h->nr_huge_pages_node[nid]++;
677 spin_unlock(&hugetlb_lock);
678 put_page(page); /* free it into the hugepage allocator */
681 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
684 int nr_pages = 1 << order;
685 struct page *p = page + 1;
687 /* we rely on prep_new_huge_page to set the destructor */
688 set_compound_order(page, order);
690 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
692 set_page_count(p, 0);
693 p->first_page = page;
698 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
699 * transparent huge pages. See the PageTransHuge() documentation for more
702 int PageHuge(struct page *page)
704 compound_page_dtor *dtor;
706 if (!PageCompound(page))
709 page = compound_head(page);
710 dtor = get_compound_page_dtor(page);
712 return dtor == free_huge_page;
714 EXPORT_SYMBOL_GPL(PageHuge);
716 pgoff_t __basepage_index(struct page *page)
718 struct page *page_head = compound_head(page);
719 pgoff_t index = page_index(page_head);
720 unsigned long compound_idx;
722 if (!PageHuge(page_head))
723 return page_index(page);
725 if (compound_order(page_head) >= MAX_ORDER)
726 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
728 compound_idx = page - page_head;
730 return (index << compound_order(page_head)) + compound_idx;
733 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
737 if (h->order >= MAX_ORDER)
740 page = alloc_pages_exact_node(nid,
741 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
742 __GFP_REPEAT|__GFP_NOWARN,
745 if (arch_prepare_hugepage(page)) {
746 __free_pages(page, huge_page_order(h));
749 prep_new_huge_page(h, page, nid);
756 * common helper functions for hstate_next_node_to_{alloc|free}.
757 * We may have allocated or freed a huge page based on a different
758 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
759 * be outside of *nodes_allowed. Ensure that we use an allowed
760 * node for alloc or free.
762 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
764 nid = next_node(nid, *nodes_allowed);
765 if (nid == MAX_NUMNODES)
766 nid = first_node(*nodes_allowed);
767 VM_BUG_ON(nid >= MAX_NUMNODES);
772 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
774 if (!node_isset(nid, *nodes_allowed))
775 nid = next_node_allowed(nid, nodes_allowed);
780 * returns the previously saved node ["this node"] from which to
781 * allocate a persistent huge page for the pool and advance the
782 * next node from which to allocate, handling wrap at end of node
785 static int hstate_next_node_to_alloc(struct hstate *h,
786 nodemask_t *nodes_allowed)
790 VM_BUG_ON(!nodes_allowed);
792 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
793 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
799 * helper for free_pool_huge_page() - return the previously saved
800 * node ["this node"] from which to free a huge page. Advance the
801 * next node id whether or not we find a free huge page to free so
802 * that the next attempt to free addresses the next node.
804 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
808 VM_BUG_ON(!nodes_allowed);
810 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
811 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
816 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
817 for (nr_nodes = nodes_weight(*mask); \
819 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
822 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
823 for (nr_nodes = nodes_weight(*mask); \
825 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
828 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
834 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
835 page = alloc_fresh_huge_page_node(h, node);
843 count_vm_event(HTLB_BUDDY_PGALLOC);
845 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
851 * Free huge page from pool from next node to free.
852 * Attempt to keep persistent huge pages more or less
853 * balanced over allowed nodes.
854 * Called with hugetlb_lock locked.
856 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
862 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
864 * If we're returning unused surplus pages, only examine
865 * nodes with surplus pages.
867 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
868 !list_empty(&h->hugepage_freelists[node])) {
870 list_entry(h->hugepage_freelists[node].next,
872 list_del(&page->lru);
873 h->free_huge_pages--;
874 h->free_huge_pages_node[node]--;
876 h->surplus_huge_pages--;
877 h->surplus_huge_pages_node[node]--;
879 update_and_free_page(h, page);
889 * Dissolve a given free hugepage into free buddy pages. This function does
890 * nothing for in-use (including surplus) hugepages.
892 static void dissolve_free_huge_page(struct page *page)
894 spin_lock(&hugetlb_lock);
895 if (PageHuge(page) && !page_count(page)) {
896 struct hstate *h = page_hstate(page);
897 int nid = page_to_nid(page);
898 list_del(&page->lru);
899 h->free_huge_pages--;
900 h->free_huge_pages_node[nid]--;
901 update_and_free_page(h, page);
903 spin_unlock(&hugetlb_lock);
907 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
908 * make specified memory blocks removable from the system.
909 * Note that start_pfn should aligned with (minimum) hugepage size.
911 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
913 unsigned int order = 8 * sizeof(void *);
917 /* Set scan step to minimum hugepage size */
919 if (order > huge_page_order(h))
920 order = huge_page_order(h);
921 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
922 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
923 dissolve_free_huge_page(pfn_to_page(pfn));
926 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
931 if (h->order >= MAX_ORDER)
935 * Assume we will successfully allocate the surplus page to
936 * prevent racing processes from causing the surplus to exceed
939 * This however introduces a different race, where a process B
940 * tries to grow the static hugepage pool while alloc_pages() is
941 * called by process A. B will only examine the per-node
942 * counters in determining if surplus huge pages can be
943 * converted to normal huge pages in adjust_pool_surplus(). A
944 * won't be able to increment the per-node counter, until the
945 * lock is dropped by B, but B doesn't drop hugetlb_lock until
946 * no more huge pages can be converted from surplus to normal
947 * state (and doesn't try to convert again). Thus, we have a
948 * case where a surplus huge page exists, the pool is grown, and
949 * the surplus huge page still exists after, even though it
950 * should just have been converted to a normal huge page. This
951 * does not leak memory, though, as the hugepage will be freed
952 * once it is out of use. It also does not allow the counters to
953 * go out of whack in adjust_pool_surplus() as we don't modify
954 * the node values until we've gotten the hugepage and only the
955 * per-node value is checked there.
957 spin_lock(&hugetlb_lock);
958 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
959 spin_unlock(&hugetlb_lock);
963 h->surplus_huge_pages++;
965 spin_unlock(&hugetlb_lock);
967 if (nid == NUMA_NO_NODE)
968 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
969 __GFP_REPEAT|__GFP_NOWARN,
972 page = alloc_pages_exact_node(nid,
973 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
974 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
976 if (page && arch_prepare_hugepage(page)) {
977 __free_pages(page, huge_page_order(h));
981 spin_lock(&hugetlb_lock);
983 INIT_LIST_HEAD(&page->lru);
984 r_nid = page_to_nid(page);
985 set_compound_page_dtor(page, free_huge_page);
986 set_hugetlb_cgroup(page, NULL);
988 * We incremented the global counters already
990 h->nr_huge_pages_node[r_nid]++;
991 h->surplus_huge_pages_node[r_nid]++;
992 __count_vm_event(HTLB_BUDDY_PGALLOC);
995 h->surplus_huge_pages--;
996 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
998 spin_unlock(&hugetlb_lock);
1004 * This allocation function is useful in the context where vma is irrelevant.
1005 * E.g. soft-offlining uses this function because it only cares physical
1006 * address of error page.
1008 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1010 struct page *page = NULL;
1012 spin_lock(&hugetlb_lock);
1013 if (h->free_huge_pages - h->resv_huge_pages > 0)
1014 page = dequeue_huge_page_node(h, nid);
1015 spin_unlock(&hugetlb_lock);
1018 page = alloc_buddy_huge_page(h, nid);
1024 * Increase the hugetlb pool such that it can accommodate a reservation
1027 static int gather_surplus_pages(struct hstate *h, int delta)
1029 struct list_head surplus_list;
1030 struct page *page, *tmp;
1032 int needed, allocated;
1033 bool alloc_ok = true;
1035 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1037 h->resv_huge_pages += delta;
1042 INIT_LIST_HEAD(&surplus_list);
1046 spin_unlock(&hugetlb_lock);
1047 for (i = 0; i < needed; i++) {
1048 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1053 list_add(&page->lru, &surplus_list);
1058 * After retaking hugetlb_lock, we need to recalculate 'needed'
1059 * because either resv_huge_pages or free_huge_pages may have changed.
1061 spin_lock(&hugetlb_lock);
1062 needed = (h->resv_huge_pages + delta) -
1063 (h->free_huge_pages + allocated);
1068 * We were not able to allocate enough pages to
1069 * satisfy the entire reservation so we free what
1070 * we've allocated so far.
1075 * The surplus_list now contains _at_least_ the number of extra pages
1076 * needed to accommodate the reservation. Add the appropriate number
1077 * of pages to the hugetlb pool and free the extras back to the buddy
1078 * allocator. Commit the entire reservation here to prevent another
1079 * process from stealing the pages as they are added to the pool but
1080 * before they are reserved.
1082 needed += allocated;
1083 h->resv_huge_pages += delta;
1086 /* Free the needed pages to the hugetlb pool */
1087 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1091 * This page is now managed by the hugetlb allocator and has
1092 * no users -- drop the buddy allocator's reference.
1094 put_page_testzero(page);
1095 VM_BUG_ON(page_count(page));
1096 enqueue_huge_page(h, page);
1099 spin_unlock(&hugetlb_lock);
1101 /* Free unnecessary surplus pages to the buddy allocator */
1102 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1104 spin_lock(&hugetlb_lock);
1110 * When releasing a hugetlb pool reservation, any surplus pages that were
1111 * allocated to satisfy the reservation must be explicitly freed if they were
1113 * Called with hugetlb_lock held.
1115 static void return_unused_surplus_pages(struct hstate *h,
1116 unsigned long unused_resv_pages)
1118 unsigned long nr_pages;
1120 /* Uncommit the reservation */
1121 h->resv_huge_pages -= unused_resv_pages;
1123 /* Cannot return gigantic pages currently */
1124 if (h->order >= MAX_ORDER)
1127 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1130 * We want to release as many surplus pages as possible, spread
1131 * evenly across all nodes with memory. Iterate across these nodes
1132 * until we can no longer free unreserved surplus pages. This occurs
1133 * when the nodes with surplus pages have no free pages.
1134 * free_pool_huge_page() will balance the the freed pages across the
1135 * on-line nodes with memory and will handle the hstate accounting.
1137 while (nr_pages--) {
1138 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1144 * Determine if the huge page at addr within the vma has an associated
1145 * reservation. Where it does not we will need to logically increase
1146 * reservation and actually increase subpool usage before an allocation
1147 * can occur. Where any new reservation would be required the
1148 * reservation change is prepared, but not committed. Once the page
1149 * has been allocated from the subpool and instantiated the change should
1150 * be committed via vma_commit_reservation. No action is required on
1153 static long vma_needs_reservation(struct hstate *h,
1154 struct vm_area_struct *vma, unsigned long addr)
1156 struct address_space *mapping = vma->vm_file->f_mapping;
1157 struct inode *inode = mapping->host;
1159 if (vma->vm_flags & VM_MAYSHARE) {
1160 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1161 return region_chg(&inode->i_mapping->private_list,
1164 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1169 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1170 struct resv_map *resv = vma_resv_map(vma);
1172 err = region_chg(&resv->regions, idx, idx + 1);
1178 static void vma_commit_reservation(struct hstate *h,
1179 struct vm_area_struct *vma, unsigned long addr)
1181 struct address_space *mapping = vma->vm_file->f_mapping;
1182 struct inode *inode = mapping->host;
1184 if (vma->vm_flags & VM_MAYSHARE) {
1185 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1186 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1188 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1189 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1190 struct resv_map *resv = vma_resv_map(vma);
1192 /* Mark this page used in the map. */
1193 region_add(&resv->regions, idx, idx + 1);
1197 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1198 unsigned long addr, int avoid_reserve)
1200 struct hugepage_subpool *spool = subpool_vma(vma);
1201 struct hstate *h = hstate_vma(vma);
1205 struct hugetlb_cgroup *h_cg;
1207 idx = hstate_index(h);
1209 * Processes that did not create the mapping will have no
1210 * reserves and will not have accounted against subpool
1211 * limit. Check that the subpool limit can be made before
1212 * satisfying the allocation MAP_NORESERVE mappings may also
1213 * need pages and subpool limit allocated allocated if no reserve
1216 chg = vma_needs_reservation(h, vma, addr);
1218 return ERR_PTR(-ENOMEM);
1219 if (chg || avoid_reserve)
1220 if (hugepage_subpool_get_pages(spool, 1))
1221 return ERR_PTR(-ENOSPC);
1223 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1225 if (chg || avoid_reserve)
1226 hugepage_subpool_put_pages(spool, 1);
1227 return ERR_PTR(-ENOSPC);
1229 spin_lock(&hugetlb_lock);
1230 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1232 spin_unlock(&hugetlb_lock);
1233 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1235 hugetlb_cgroup_uncharge_cgroup(idx,
1236 pages_per_huge_page(h),
1238 if (chg || avoid_reserve)
1239 hugepage_subpool_put_pages(spool, 1);
1240 return ERR_PTR(-ENOSPC);
1242 spin_lock(&hugetlb_lock);
1243 list_move(&page->lru, &h->hugepage_activelist);
1246 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1247 spin_unlock(&hugetlb_lock);
1249 set_page_private(page, (unsigned long)spool);
1251 vma_commit_reservation(h, vma, addr);
1256 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1257 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1258 * where no ERR_VALUE is expected to be returned.
1260 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1261 unsigned long addr, int avoid_reserve)
1263 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1269 int __weak alloc_bootmem_huge_page(struct hstate *h)
1271 struct huge_bootmem_page *m;
1274 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1277 addr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
1278 huge_page_size(h), huge_page_size(h), 0);
1282 * Use the beginning of the huge page to store the
1283 * huge_bootmem_page struct (until gather_bootmem
1284 * puts them into the mem_map).
1293 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1294 /* Put them into a private list first because mem_map is not up yet */
1295 list_add(&m->list, &huge_boot_pages);
1300 static void prep_compound_huge_page(struct page *page, int order)
1302 if (unlikely(order > (MAX_ORDER - 1)))
1303 prep_compound_gigantic_page(page, order);
1305 prep_compound_page(page, order);
1308 /* Put bootmem huge pages into the standard lists after mem_map is up */
1309 static void __init gather_bootmem_prealloc(void)
1311 struct huge_bootmem_page *m;
1313 list_for_each_entry(m, &huge_boot_pages, list) {
1314 struct hstate *h = m->hstate;
1317 #ifdef CONFIG_HIGHMEM
1318 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1319 free_bootmem_late((unsigned long)m,
1320 sizeof(struct huge_bootmem_page));
1322 page = virt_to_page(m);
1324 __ClearPageReserved(page);
1325 WARN_ON(page_count(page) != 1);
1326 prep_compound_huge_page(page, h->order);
1327 prep_new_huge_page(h, page, page_to_nid(page));
1329 * If we had gigantic hugepages allocated at boot time, we need
1330 * to restore the 'stolen' pages to totalram_pages in order to
1331 * fix confusing memory reports from free(1) and another
1332 * side-effects, like CommitLimit going negative.
1334 if (h->order > (MAX_ORDER - 1))
1335 adjust_managed_page_count(page, 1 << h->order);
1339 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1343 for (i = 0; i < h->max_huge_pages; ++i) {
1344 if (h->order >= MAX_ORDER) {
1345 if (!alloc_bootmem_huge_page(h))
1347 } else if (!alloc_fresh_huge_page(h,
1348 &node_states[N_MEMORY]))
1351 h->max_huge_pages = i;
1354 static void __init hugetlb_init_hstates(void)
1358 for_each_hstate(h) {
1359 /* oversize hugepages were init'ed in early boot */
1360 if (h->order < MAX_ORDER)
1361 hugetlb_hstate_alloc_pages(h);
1365 static char * __init memfmt(char *buf, unsigned long n)
1367 if (n >= (1UL << 30))
1368 sprintf(buf, "%lu GB", n >> 30);
1369 else if (n >= (1UL << 20))
1370 sprintf(buf, "%lu MB", n >> 20);
1372 sprintf(buf, "%lu KB", n >> 10);
1376 static void __init report_hugepages(void)
1380 for_each_hstate(h) {
1382 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1383 memfmt(buf, huge_page_size(h)),
1384 h->free_huge_pages);
1388 #ifdef CONFIG_HIGHMEM
1389 static void try_to_free_low(struct hstate *h, unsigned long count,
1390 nodemask_t *nodes_allowed)
1394 if (h->order >= MAX_ORDER)
1397 for_each_node_mask(i, *nodes_allowed) {
1398 struct page *page, *next;
1399 struct list_head *freel = &h->hugepage_freelists[i];
1400 list_for_each_entry_safe(page, next, freel, lru) {
1401 if (count >= h->nr_huge_pages)
1403 if (PageHighMem(page))
1405 list_del(&page->lru);
1406 update_and_free_page(h, page);
1407 h->free_huge_pages--;
1408 h->free_huge_pages_node[page_to_nid(page)]--;
1413 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1414 nodemask_t *nodes_allowed)
1420 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1421 * balanced by operating on them in a round-robin fashion.
1422 * Returns 1 if an adjustment was made.
1424 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1429 VM_BUG_ON(delta != -1 && delta != 1);
1432 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1433 if (h->surplus_huge_pages_node[node])
1437 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1438 if (h->surplus_huge_pages_node[node] <
1439 h->nr_huge_pages_node[node])
1446 h->surplus_huge_pages += delta;
1447 h->surplus_huge_pages_node[node] += delta;
1451 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1452 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1453 nodemask_t *nodes_allowed)
1455 unsigned long min_count, ret;
1457 if (h->order >= MAX_ORDER)
1458 return h->max_huge_pages;
1461 * Increase the pool size
1462 * First take pages out of surplus state. Then make up the
1463 * remaining difference by allocating fresh huge pages.
1465 * We might race with alloc_buddy_huge_page() here and be unable
1466 * to convert a surplus huge page to a normal huge page. That is
1467 * not critical, though, it just means the overall size of the
1468 * pool might be one hugepage larger than it needs to be, but
1469 * within all the constraints specified by the sysctls.
1471 spin_lock(&hugetlb_lock);
1472 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1473 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1477 while (count > persistent_huge_pages(h)) {
1479 * If this allocation races such that we no longer need the
1480 * page, free_huge_page will handle it by freeing the page
1481 * and reducing the surplus.
1483 spin_unlock(&hugetlb_lock);
1484 ret = alloc_fresh_huge_page(h, nodes_allowed);
1485 spin_lock(&hugetlb_lock);
1489 /* Bail for signals. Probably ctrl-c from user */
1490 if (signal_pending(current))
1495 * Decrease the pool size
1496 * First return free pages to the buddy allocator (being careful
1497 * to keep enough around to satisfy reservations). Then place
1498 * pages into surplus state as needed so the pool will shrink
1499 * to the desired size as pages become free.
1501 * By placing pages into the surplus state independent of the
1502 * overcommit value, we are allowing the surplus pool size to
1503 * exceed overcommit. There are few sane options here. Since
1504 * alloc_buddy_huge_page() is checking the global counter,
1505 * though, we'll note that we're not allowed to exceed surplus
1506 * and won't grow the pool anywhere else. Not until one of the
1507 * sysctls are changed, or the surplus pages go out of use.
1509 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1510 min_count = max(count, min_count);
1511 try_to_free_low(h, min_count, nodes_allowed);
1512 while (min_count < persistent_huge_pages(h)) {
1513 if (!free_pool_huge_page(h, nodes_allowed, 0))
1516 while (count < persistent_huge_pages(h)) {
1517 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1521 ret = persistent_huge_pages(h);
1522 spin_unlock(&hugetlb_lock);
1526 #define HSTATE_ATTR_RO(_name) \
1527 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1529 #define HSTATE_ATTR(_name) \
1530 static struct kobj_attribute _name##_attr = \
1531 __ATTR(_name, 0644, _name##_show, _name##_store)
1533 static struct kobject *hugepages_kobj;
1534 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1536 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1538 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1542 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1543 if (hstate_kobjs[i] == kobj) {
1545 *nidp = NUMA_NO_NODE;
1549 return kobj_to_node_hstate(kobj, nidp);
1552 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1553 struct kobj_attribute *attr, char *buf)
1556 unsigned long nr_huge_pages;
1559 h = kobj_to_hstate(kobj, &nid);
1560 if (nid == NUMA_NO_NODE)
1561 nr_huge_pages = h->nr_huge_pages;
1563 nr_huge_pages = h->nr_huge_pages_node[nid];
1565 return sprintf(buf, "%lu\n", nr_huge_pages);
1568 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1569 struct kobject *kobj, struct kobj_attribute *attr,
1570 const char *buf, size_t len)
1574 unsigned long count;
1576 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1578 err = kstrtoul(buf, 10, &count);
1582 h = kobj_to_hstate(kobj, &nid);
1583 if (h->order >= MAX_ORDER) {
1588 if (nid == NUMA_NO_NODE) {
1590 * global hstate attribute
1592 if (!(obey_mempolicy &&
1593 init_nodemask_of_mempolicy(nodes_allowed))) {
1594 NODEMASK_FREE(nodes_allowed);
1595 nodes_allowed = &node_states[N_MEMORY];
1597 } else if (nodes_allowed) {
1599 * per node hstate attribute: adjust count to global,
1600 * but restrict alloc/free to the specified node.
1602 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1603 init_nodemask_of_node(nodes_allowed, nid);
1605 nodes_allowed = &node_states[N_MEMORY];
1607 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1609 if (nodes_allowed != &node_states[N_MEMORY])
1610 NODEMASK_FREE(nodes_allowed);
1614 NODEMASK_FREE(nodes_allowed);
1618 static ssize_t nr_hugepages_show(struct kobject *kobj,
1619 struct kobj_attribute *attr, char *buf)
1621 return nr_hugepages_show_common(kobj, attr, buf);
1624 static ssize_t nr_hugepages_store(struct kobject *kobj,
1625 struct kobj_attribute *attr, const char *buf, size_t len)
1627 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1629 HSTATE_ATTR(nr_hugepages);
1634 * hstate attribute for optionally mempolicy-based constraint on persistent
1635 * huge page alloc/free.
1637 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1638 struct kobj_attribute *attr, char *buf)
1640 return nr_hugepages_show_common(kobj, attr, buf);
1643 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1644 struct kobj_attribute *attr, const char *buf, size_t len)
1646 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1648 HSTATE_ATTR(nr_hugepages_mempolicy);
1652 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1653 struct kobj_attribute *attr, char *buf)
1655 struct hstate *h = kobj_to_hstate(kobj, NULL);
1656 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1659 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1660 struct kobj_attribute *attr, const char *buf, size_t count)
1663 unsigned long input;
1664 struct hstate *h = kobj_to_hstate(kobj, NULL);
1666 if (h->order >= MAX_ORDER)
1669 err = kstrtoul(buf, 10, &input);
1673 spin_lock(&hugetlb_lock);
1674 h->nr_overcommit_huge_pages = input;
1675 spin_unlock(&hugetlb_lock);
1679 HSTATE_ATTR(nr_overcommit_hugepages);
1681 static ssize_t free_hugepages_show(struct kobject *kobj,
1682 struct kobj_attribute *attr, char *buf)
1685 unsigned long free_huge_pages;
1688 h = kobj_to_hstate(kobj, &nid);
1689 if (nid == NUMA_NO_NODE)
1690 free_huge_pages = h->free_huge_pages;
1692 free_huge_pages = h->free_huge_pages_node[nid];
1694 return sprintf(buf, "%lu\n", free_huge_pages);
1696 HSTATE_ATTR_RO(free_hugepages);
1698 static ssize_t resv_hugepages_show(struct kobject *kobj,
1699 struct kobj_attribute *attr, char *buf)
1701 struct hstate *h = kobj_to_hstate(kobj, NULL);
1702 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1704 HSTATE_ATTR_RO(resv_hugepages);
1706 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1707 struct kobj_attribute *attr, char *buf)
1710 unsigned long surplus_huge_pages;
1713 h = kobj_to_hstate(kobj, &nid);
1714 if (nid == NUMA_NO_NODE)
1715 surplus_huge_pages = h->surplus_huge_pages;
1717 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1719 return sprintf(buf, "%lu\n", surplus_huge_pages);
1721 HSTATE_ATTR_RO(surplus_hugepages);
1723 static struct attribute *hstate_attrs[] = {
1724 &nr_hugepages_attr.attr,
1725 &nr_overcommit_hugepages_attr.attr,
1726 &free_hugepages_attr.attr,
1727 &resv_hugepages_attr.attr,
1728 &surplus_hugepages_attr.attr,
1730 &nr_hugepages_mempolicy_attr.attr,
1735 static struct attribute_group hstate_attr_group = {
1736 .attrs = hstate_attrs,
1739 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1740 struct kobject **hstate_kobjs,
1741 struct attribute_group *hstate_attr_group)
1744 int hi = hstate_index(h);
1746 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1747 if (!hstate_kobjs[hi])
1750 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1752 kobject_put(hstate_kobjs[hi]);
1757 static void __init hugetlb_sysfs_init(void)
1762 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1763 if (!hugepages_kobj)
1766 for_each_hstate(h) {
1767 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1768 hstate_kobjs, &hstate_attr_group);
1770 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1777 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1778 * with node devices in node_devices[] using a parallel array. The array
1779 * index of a node device or _hstate == node id.
1780 * This is here to avoid any static dependency of the node device driver, in
1781 * the base kernel, on the hugetlb module.
1783 struct node_hstate {
1784 struct kobject *hugepages_kobj;
1785 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1787 struct node_hstate node_hstates[MAX_NUMNODES];
1790 * A subset of global hstate attributes for node devices
1792 static struct attribute *per_node_hstate_attrs[] = {
1793 &nr_hugepages_attr.attr,
1794 &free_hugepages_attr.attr,
1795 &surplus_hugepages_attr.attr,
1799 static struct attribute_group per_node_hstate_attr_group = {
1800 .attrs = per_node_hstate_attrs,
1804 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1805 * Returns node id via non-NULL nidp.
1807 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1811 for (nid = 0; nid < nr_node_ids; nid++) {
1812 struct node_hstate *nhs = &node_hstates[nid];
1814 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1815 if (nhs->hstate_kobjs[i] == kobj) {
1827 * Unregister hstate attributes from a single node device.
1828 * No-op if no hstate attributes attached.
1830 static void hugetlb_unregister_node(struct node *node)
1833 struct node_hstate *nhs = &node_hstates[node->dev.id];
1835 if (!nhs->hugepages_kobj)
1836 return; /* no hstate attributes */
1838 for_each_hstate(h) {
1839 int idx = hstate_index(h);
1840 if (nhs->hstate_kobjs[idx]) {
1841 kobject_put(nhs->hstate_kobjs[idx]);
1842 nhs->hstate_kobjs[idx] = NULL;
1846 kobject_put(nhs->hugepages_kobj);
1847 nhs->hugepages_kobj = NULL;
1851 * hugetlb module exit: unregister hstate attributes from node devices
1854 static void hugetlb_unregister_all_nodes(void)
1859 * disable node device registrations.
1861 register_hugetlbfs_with_node(NULL, NULL);
1864 * remove hstate attributes from any nodes that have them.
1866 for (nid = 0; nid < nr_node_ids; nid++)
1867 hugetlb_unregister_node(node_devices[nid]);
1871 * Register hstate attributes for a single node device.
1872 * No-op if attributes already registered.
1874 static void hugetlb_register_node(struct node *node)
1877 struct node_hstate *nhs = &node_hstates[node->dev.id];
1880 if (nhs->hugepages_kobj)
1881 return; /* already allocated */
1883 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1885 if (!nhs->hugepages_kobj)
1888 for_each_hstate(h) {
1889 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1891 &per_node_hstate_attr_group);
1893 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1894 h->name, node->dev.id);
1895 hugetlb_unregister_node(node);
1902 * hugetlb init time: register hstate attributes for all registered node
1903 * devices of nodes that have memory. All on-line nodes should have
1904 * registered their associated device by this time.
1906 static void hugetlb_register_all_nodes(void)
1910 for_each_node_state(nid, N_MEMORY) {
1911 struct node *node = node_devices[nid];
1912 if (node->dev.id == nid)
1913 hugetlb_register_node(node);
1917 * Let the node device driver know we're here so it can
1918 * [un]register hstate attributes on node hotplug.
1920 register_hugetlbfs_with_node(hugetlb_register_node,
1921 hugetlb_unregister_node);
1923 #else /* !CONFIG_NUMA */
1925 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1933 static void hugetlb_unregister_all_nodes(void) { }
1935 static void hugetlb_register_all_nodes(void) { }
1939 static void __exit hugetlb_exit(void)
1943 hugetlb_unregister_all_nodes();
1945 for_each_hstate(h) {
1946 kobject_put(hstate_kobjs[hstate_index(h)]);
1949 kobject_put(hugepages_kobj);
1951 module_exit(hugetlb_exit);
1953 static int __init hugetlb_init(void)
1955 /* Some platform decide whether they support huge pages at boot
1956 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1957 * there is no such support
1959 if (HPAGE_SHIFT == 0)
1962 if (!size_to_hstate(default_hstate_size)) {
1963 default_hstate_size = HPAGE_SIZE;
1964 if (!size_to_hstate(default_hstate_size))
1965 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1967 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1968 if (default_hstate_max_huge_pages)
1969 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1971 hugetlb_init_hstates();
1972 gather_bootmem_prealloc();
1975 hugetlb_sysfs_init();
1976 hugetlb_register_all_nodes();
1977 hugetlb_cgroup_file_init();
1981 module_init(hugetlb_init);
1983 /* Should be called on processing a hugepagesz=... option */
1984 void __init hugetlb_add_hstate(unsigned order)
1989 if (size_to_hstate(PAGE_SIZE << order)) {
1990 pr_warning("hugepagesz= specified twice, ignoring\n");
1993 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
1995 h = &hstates[hugetlb_max_hstate++];
1997 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1998 h->nr_huge_pages = 0;
1999 h->free_huge_pages = 0;
2000 for (i = 0; i < MAX_NUMNODES; ++i)
2001 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2002 INIT_LIST_HEAD(&h->hugepage_activelist);
2003 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2004 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2005 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2006 huge_page_size(h)/1024);
2011 static int __init hugetlb_nrpages_setup(char *s)
2014 static unsigned long *last_mhp;
2017 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2018 * so this hugepages= parameter goes to the "default hstate".
2020 if (!hugetlb_max_hstate)
2021 mhp = &default_hstate_max_huge_pages;
2023 mhp = &parsed_hstate->max_huge_pages;
2025 if (mhp == last_mhp) {
2026 pr_warning("hugepages= specified twice without "
2027 "interleaving hugepagesz=, ignoring\n");
2031 if (sscanf(s, "%lu", mhp) <= 0)
2035 * Global state is always initialized later in hugetlb_init.
2036 * But we need to allocate >= MAX_ORDER hstates here early to still
2037 * use the bootmem allocator.
2039 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2040 hugetlb_hstate_alloc_pages(parsed_hstate);
2046 __setup("hugepages=", hugetlb_nrpages_setup);
2048 static int __init hugetlb_default_setup(char *s)
2050 default_hstate_size = memparse(s, &s);
2053 __setup("default_hugepagesz=", hugetlb_default_setup);
2055 static unsigned int cpuset_mems_nr(unsigned int *array)
2058 unsigned int nr = 0;
2060 for_each_node_mask(node, cpuset_current_mems_allowed)
2066 #ifdef CONFIG_SYSCTL
2067 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2068 struct ctl_table *table, int write,
2069 void __user *buffer, size_t *length, loff_t *ppos)
2071 struct hstate *h = &default_hstate;
2075 tmp = h->max_huge_pages;
2077 if (write && h->order >= MAX_ORDER)
2081 table->maxlen = sizeof(unsigned long);
2082 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2087 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2088 GFP_KERNEL | __GFP_NORETRY);
2089 if (!(obey_mempolicy &&
2090 init_nodemask_of_mempolicy(nodes_allowed))) {
2091 NODEMASK_FREE(nodes_allowed);
2092 nodes_allowed = &node_states[N_MEMORY];
2094 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2096 if (nodes_allowed != &node_states[N_MEMORY])
2097 NODEMASK_FREE(nodes_allowed);
2103 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2104 void __user *buffer, size_t *length, loff_t *ppos)
2107 return hugetlb_sysctl_handler_common(false, table, write,
2108 buffer, length, ppos);
2112 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2113 void __user *buffer, size_t *length, loff_t *ppos)
2115 return hugetlb_sysctl_handler_common(true, table, write,
2116 buffer, length, ppos);
2118 #endif /* CONFIG_NUMA */
2120 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
2121 void __user *buffer,
2122 size_t *length, loff_t *ppos)
2124 proc_dointvec(table, write, buffer, length, ppos);
2125 if (hugepages_treat_as_movable)
2126 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
2128 htlb_alloc_mask = GFP_HIGHUSER;
2132 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2133 void __user *buffer,
2134 size_t *length, loff_t *ppos)
2136 struct hstate *h = &default_hstate;
2140 tmp = h->nr_overcommit_huge_pages;
2142 if (write && h->order >= MAX_ORDER)
2146 table->maxlen = sizeof(unsigned long);
2147 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2152 spin_lock(&hugetlb_lock);
2153 h->nr_overcommit_huge_pages = tmp;
2154 spin_unlock(&hugetlb_lock);
2160 #endif /* CONFIG_SYSCTL */
2162 void hugetlb_report_meminfo(struct seq_file *m)
2164 struct hstate *h = &default_hstate;
2166 "HugePages_Total: %5lu\n"
2167 "HugePages_Free: %5lu\n"
2168 "HugePages_Rsvd: %5lu\n"
2169 "HugePages_Surp: %5lu\n"
2170 "Hugepagesize: %8lu kB\n",
2174 h->surplus_huge_pages,
2175 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2178 int hugetlb_report_node_meminfo(int nid, char *buf)
2180 struct hstate *h = &default_hstate;
2182 "Node %d HugePages_Total: %5u\n"
2183 "Node %d HugePages_Free: %5u\n"
2184 "Node %d HugePages_Surp: %5u\n",
2185 nid, h->nr_huge_pages_node[nid],
2186 nid, h->free_huge_pages_node[nid],
2187 nid, h->surplus_huge_pages_node[nid]);
2190 void hugetlb_show_meminfo(void)
2195 for_each_node_state(nid, N_MEMORY)
2197 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2199 h->nr_huge_pages_node[nid],
2200 h->free_huge_pages_node[nid],
2201 h->surplus_huge_pages_node[nid],
2202 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2205 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2206 unsigned long hugetlb_total_pages(void)
2209 unsigned long nr_total_pages = 0;
2212 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2213 return nr_total_pages;
2216 static int hugetlb_acct_memory(struct hstate *h, long delta)
2220 spin_lock(&hugetlb_lock);
2222 * When cpuset is configured, it breaks the strict hugetlb page
2223 * reservation as the accounting is done on a global variable. Such
2224 * reservation is completely rubbish in the presence of cpuset because
2225 * the reservation is not checked against page availability for the
2226 * current cpuset. Application can still potentially OOM'ed by kernel
2227 * with lack of free htlb page in cpuset that the task is in.
2228 * Attempt to enforce strict accounting with cpuset is almost
2229 * impossible (or too ugly) because cpuset is too fluid that
2230 * task or memory node can be dynamically moved between cpusets.
2232 * The change of semantics for shared hugetlb mapping with cpuset is
2233 * undesirable. However, in order to preserve some of the semantics,
2234 * we fall back to check against current free page availability as
2235 * a best attempt and hopefully to minimize the impact of changing
2236 * semantics that cpuset has.
2239 if (gather_surplus_pages(h, delta) < 0)
2242 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2243 return_unused_surplus_pages(h, delta);
2250 return_unused_surplus_pages(h, (unsigned long) -delta);
2253 spin_unlock(&hugetlb_lock);
2257 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2259 struct resv_map *resv = vma_resv_map(vma);
2262 * This new VMA should share its siblings reservation map if present.
2263 * The VMA will only ever have a valid reservation map pointer where
2264 * it is being copied for another still existing VMA. As that VMA
2265 * has a reference to the reservation map it cannot disappear until
2266 * after this open call completes. It is therefore safe to take a
2267 * new reference here without additional locking.
2270 kref_get(&resv->refs);
2273 static void resv_map_put(struct vm_area_struct *vma)
2275 struct resv_map *resv = vma_resv_map(vma);
2279 kref_put(&resv->refs, resv_map_release);
2282 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2284 struct hstate *h = hstate_vma(vma);
2285 struct resv_map *resv = vma_resv_map(vma);
2286 struct hugepage_subpool *spool = subpool_vma(vma);
2287 unsigned long reserve;
2288 unsigned long start;
2292 start = vma_hugecache_offset(h, vma, vma->vm_start);
2293 end = vma_hugecache_offset(h, vma, vma->vm_end);
2295 reserve = (end - start) -
2296 region_count(&resv->regions, start, end);
2301 hugetlb_acct_memory(h, -reserve);
2302 hugepage_subpool_put_pages(spool, reserve);
2308 * We cannot handle pagefaults against hugetlb pages at all. They cause
2309 * handle_mm_fault() to try to instantiate regular-sized pages in the
2310 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2313 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2319 const struct vm_operations_struct hugetlb_vm_ops = {
2320 .fault = hugetlb_vm_op_fault,
2321 .open = hugetlb_vm_op_open,
2322 .close = hugetlb_vm_op_close,
2325 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2331 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2332 vma->vm_page_prot)));
2334 entry = huge_pte_wrprotect(mk_huge_pte(page,
2335 vma->vm_page_prot));
2337 entry = pte_mkyoung(entry);
2338 entry = pte_mkhuge(entry);
2339 entry = arch_make_huge_pte(entry, vma, page, writable);
2344 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2345 unsigned long address, pte_t *ptep)
2349 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2350 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2351 update_mmu_cache(vma, address, ptep);
2355 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2356 struct vm_area_struct *vma)
2358 pte_t *src_pte, *dst_pte, entry;
2359 struct page *ptepage;
2362 struct hstate *h = hstate_vma(vma);
2363 unsigned long sz = huge_page_size(h);
2365 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2367 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2368 src_pte = huge_pte_offset(src, addr);
2371 dst_pte = huge_pte_alloc(dst, addr, sz);
2375 /* If the pagetables are shared don't copy or take references */
2376 if (dst_pte == src_pte)
2379 spin_lock(&dst->page_table_lock);
2380 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2381 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2383 huge_ptep_set_wrprotect(src, addr, src_pte);
2384 entry = huge_ptep_get(src_pte);
2385 ptepage = pte_page(entry);
2387 page_dup_rmap(ptepage);
2388 set_huge_pte_at(dst, addr, dst_pte, entry);
2390 spin_unlock(&src->page_table_lock);
2391 spin_unlock(&dst->page_table_lock);
2399 static int is_hugetlb_entry_migration(pte_t pte)
2403 if (huge_pte_none(pte) || pte_present(pte))
2405 swp = pte_to_swp_entry(pte);
2406 if (non_swap_entry(swp) && is_migration_entry(swp))
2412 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2416 if (huge_pte_none(pte) || pte_present(pte))
2418 swp = pte_to_swp_entry(pte);
2419 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2425 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2426 unsigned long start, unsigned long end,
2427 struct page *ref_page)
2429 int force_flush = 0;
2430 struct mm_struct *mm = vma->vm_mm;
2431 unsigned long address;
2435 struct hstate *h = hstate_vma(vma);
2436 unsigned long sz = huge_page_size(h);
2437 const unsigned long mmun_start = start; /* For mmu_notifiers */
2438 const unsigned long mmun_end = end; /* For mmu_notifiers */
2440 WARN_ON(!is_vm_hugetlb_page(vma));
2441 BUG_ON(start & ~huge_page_mask(h));
2442 BUG_ON(end & ~huge_page_mask(h));
2444 tlb_start_vma(tlb, vma);
2445 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2447 spin_lock(&mm->page_table_lock);
2448 for (address = start; address < end; address += sz) {
2449 ptep = huge_pte_offset(mm, address);
2453 if (huge_pmd_unshare(mm, &address, ptep))
2456 pte = huge_ptep_get(ptep);
2457 if (huge_pte_none(pte))
2461 * HWPoisoned hugepage is already unmapped and dropped reference
2463 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2464 huge_pte_clear(mm, address, ptep);
2468 page = pte_page(pte);
2470 * If a reference page is supplied, it is because a specific
2471 * page is being unmapped, not a range. Ensure the page we
2472 * are about to unmap is the actual page of interest.
2475 if (page != ref_page)
2479 * Mark the VMA as having unmapped its page so that
2480 * future faults in this VMA will fail rather than
2481 * looking like data was lost
2483 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2486 pte = huge_ptep_get_and_clear(mm, address, ptep);
2487 tlb_remove_tlb_entry(tlb, ptep, address);
2488 if (huge_pte_dirty(pte))
2489 set_page_dirty(page);
2491 page_remove_rmap(page);
2492 force_flush = !__tlb_remove_page(tlb, page);
2495 /* Bail out after unmapping reference page if supplied */
2499 spin_unlock(&mm->page_table_lock);
2501 * mmu_gather ran out of room to batch pages, we break out of
2502 * the PTE lock to avoid doing the potential expensive TLB invalidate
2503 * and page-free while holding it.
2508 if (address < end && !ref_page)
2511 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2512 tlb_end_vma(tlb, vma);
2515 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2516 struct vm_area_struct *vma, unsigned long start,
2517 unsigned long end, struct page *ref_page)
2519 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2522 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2523 * test will fail on a vma being torn down, and not grab a page table
2524 * on its way out. We're lucky that the flag has such an appropriate
2525 * name, and can in fact be safely cleared here. We could clear it
2526 * before the __unmap_hugepage_range above, but all that's necessary
2527 * is to clear it before releasing the i_mmap_mutex. This works
2528 * because in the context this is called, the VMA is about to be
2529 * destroyed and the i_mmap_mutex is held.
2531 vma->vm_flags &= ~VM_MAYSHARE;
2534 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2535 unsigned long end, struct page *ref_page)
2537 struct mm_struct *mm;
2538 struct mmu_gather tlb;
2542 tlb_gather_mmu(&tlb, mm, start, end);
2543 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2544 tlb_finish_mmu(&tlb, start, end);
2548 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2549 * mappping it owns the reserve page for. The intention is to unmap the page
2550 * from other VMAs and let the children be SIGKILLed if they are faulting the
2553 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2554 struct page *page, unsigned long address)
2556 struct hstate *h = hstate_vma(vma);
2557 struct vm_area_struct *iter_vma;
2558 struct address_space *mapping;
2562 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2563 * from page cache lookup which is in HPAGE_SIZE units.
2565 address = address & huge_page_mask(h);
2566 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2568 mapping = file_inode(vma->vm_file)->i_mapping;
2571 * Take the mapping lock for the duration of the table walk. As
2572 * this mapping should be shared between all the VMAs,
2573 * __unmap_hugepage_range() is called as the lock is already held
2575 mutex_lock(&mapping->i_mmap_mutex);
2576 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2577 /* Do not unmap the current VMA */
2578 if (iter_vma == vma)
2582 * Unmap the page from other VMAs without their own reserves.
2583 * They get marked to be SIGKILLed if they fault in these
2584 * areas. This is because a future no-page fault on this VMA
2585 * could insert a zeroed page instead of the data existing
2586 * from the time of fork. This would look like data corruption
2588 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2589 unmap_hugepage_range(iter_vma, address,
2590 address + huge_page_size(h), page);
2592 mutex_unlock(&mapping->i_mmap_mutex);
2598 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2599 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2600 * cannot race with other handlers or page migration.
2601 * Keep the pte_same checks anyway to make transition from the mutex easier.
2603 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2604 unsigned long address, pte_t *ptep, pte_t pte,
2605 struct page *pagecache_page)
2607 struct hstate *h = hstate_vma(vma);
2608 struct page *old_page, *new_page;
2609 int outside_reserve = 0;
2610 unsigned long mmun_start; /* For mmu_notifiers */
2611 unsigned long mmun_end; /* For mmu_notifiers */
2613 old_page = pte_page(pte);
2616 /* If no-one else is actually using this page, avoid the copy
2617 * and just make the page writable */
2618 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2619 page_move_anon_rmap(old_page, vma, address);
2620 set_huge_ptep_writable(vma, address, ptep);
2625 * If the process that created a MAP_PRIVATE mapping is about to
2626 * perform a COW due to a shared page count, attempt to satisfy
2627 * the allocation without using the existing reserves. The pagecache
2628 * page is used to determine if the reserve at this address was
2629 * consumed or not. If reserves were used, a partial faulted mapping
2630 * at the time of fork() could consume its reserves on COW instead
2631 * of the full address range.
2633 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2634 old_page != pagecache_page)
2635 outside_reserve = 1;
2637 page_cache_get(old_page);
2639 /* Drop page_table_lock as buddy allocator may be called */
2640 spin_unlock(&mm->page_table_lock);
2641 new_page = alloc_huge_page(vma, address, outside_reserve);
2643 if (IS_ERR(new_page)) {
2644 long err = PTR_ERR(new_page);
2645 page_cache_release(old_page);
2648 * If a process owning a MAP_PRIVATE mapping fails to COW,
2649 * it is due to references held by a child and an insufficient
2650 * huge page pool. To guarantee the original mappers
2651 * reliability, unmap the page from child processes. The child
2652 * may get SIGKILLed if it later faults.
2654 if (outside_reserve) {
2655 BUG_ON(huge_pte_none(pte));
2656 if (unmap_ref_private(mm, vma, old_page, address)) {
2657 BUG_ON(huge_pte_none(pte));
2658 spin_lock(&mm->page_table_lock);
2659 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2660 if (likely(pte_same(huge_ptep_get(ptep), pte)))
2661 goto retry_avoidcopy;
2663 * race occurs while re-acquiring page_table_lock, and
2671 /* Caller expects lock to be held */
2672 spin_lock(&mm->page_table_lock);
2674 return VM_FAULT_OOM;
2676 return VM_FAULT_SIGBUS;
2680 * When the original hugepage is shared one, it does not have
2681 * anon_vma prepared.
2683 if (unlikely(anon_vma_prepare(vma))) {
2684 page_cache_release(new_page);
2685 page_cache_release(old_page);
2686 /* Caller expects lock to be held */
2687 spin_lock(&mm->page_table_lock);
2688 return VM_FAULT_OOM;
2691 copy_user_huge_page(new_page, old_page, address, vma,
2692 pages_per_huge_page(h));
2693 __SetPageUptodate(new_page);
2695 mmun_start = address & huge_page_mask(h);
2696 mmun_end = mmun_start + huge_page_size(h);
2697 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2699 * Retake the page_table_lock to check for racing updates
2700 * before the page tables are altered
2702 spin_lock(&mm->page_table_lock);
2703 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2704 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2705 ClearPagePrivate(new_page);
2708 huge_ptep_clear_flush(vma, address, ptep);
2709 set_huge_pte_at(mm, address, ptep,
2710 make_huge_pte(vma, new_page, 1));
2711 page_remove_rmap(old_page);
2712 hugepage_add_new_anon_rmap(new_page, vma, address);
2713 /* Make the old page be freed below */
2714 new_page = old_page;
2716 spin_unlock(&mm->page_table_lock);
2717 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2718 page_cache_release(new_page);
2719 page_cache_release(old_page);
2721 /* Caller expects lock to be held */
2722 spin_lock(&mm->page_table_lock);
2726 /* Return the pagecache page at a given address within a VMA */
2727 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2728 struct vm_area_struct *vma, unsigned long address)
2730 struct address_space *mapping;
2733 mapping = vma->vm_file->f_mapping;
2734 idx = vma_hugecache_offset(h, vma, address);
2736 return find_lock_page(mapping, idx);
2740 * Return whether there is a pagecache page to back given address within VMA.
2741 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2743 static bool hugetlbfs_pagecache_present(struct hstate *h,
2744 struct vm_area_struct *vma, unsigned long address)
2746 struct address_space *mapping;
2750 mapping = vma->vm_file->f_mapping;
2751 idx = vma_hugecache_offset(h, vma, address);
2753 page = find_get_page(mapping, idx);
2756 return page != NULL;
2759 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2760 unsigned long address, pte_t *ptep, unsigned int flags)
2762 struct hstate *h = hstate_vma(vma);
2763 int ret = VM_FAULT_SIGBUS;
2768 struct address_space *mapping;
2772 * Currently, we are forced to kill the process in the event the
2773 * original mapper has unmapped pages from the child due to a failed
2774 * COW. Warn that such a situation has occurred as it may not be obvious
2776 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2777 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2782 mapping = vma->vm_file->f_mapping;
2783 idx = vma_hugecache_offset(h, vma, address);
2786 * Use page lock to guard against racing truncation
2787 * before we get page_table_lock.
2790 page = find_lock_page(mapping, idx);
2792 size = i_size_read(mapping->host) >> huge_page_shift(h);
2795 page = alloc_huge_page(vma, address, 0);
2797 ret = PTR_ERR(page);
2801 ret = VM_FAULT_SIGBUS;
2804 clear_huge_page(page, address, pages_per_huge_page(h));
2805 __SetPageUptodate(page);
2807 if (vma->vm_flags & VM_MAYSHARE) {
2809 struct inode *inode = mapping->host;
2811 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2818 ClearPagePrivate(page);
2820 spin_lock(&inode->i_lock);
2821 inode->i_blocks += blocks_per_huge_page(h);
2822 spin_unlock(&inode->i_lock);
2825 if (unlikely(anon_vma_prepare(vma))) {
2827 goto backout_unlocked;
2833 * If memory error occurs between mmap() and fault, some process
2834 * don't have hwpoisoned swap entry for errored virtual address.
2835 * So we need to block hugepage fault by PG_hwpoison bit check.
2837 if (unlikely(PageHWPoison(page))) {
2838 ret = VM_FAULT_HWPOISON |
2839 VM_FAULT_SET_HINDEX(hstate_index(h));
2840 goto backout_unlocked;
2845 * If we are going to COW a private mapping later, we examine the
2846 * pending reservations for this page now. This will ensure that
2847 * any allocations necessary to record that reservation occur outside
2850 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2851 if (vma_needs_reservation(h, vma, address) < 0) {
2853 goto backout_unlocked;
2856 spin_lock(&mm->page_table_lock);
2857 size = i_size_read(mapping->host) >> huge_page_shift(h);
2862 if (!huge_pte_none(huge_ptep_get(ptep)))
2866 ClearPagePrivate(page);
2867 hugepage_add_new_anon_rmap(page, vma, address);
2870 page_dup_rmap(page);
2871 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2872 && (vma->vm_flags & VM_SHARED)));
2873 set_huge_pte_at(mm, address, ptep, new_pte);
2875 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2876 /* Optimization, do the COW without a second fault */
2877 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2880 spin_unlock(&mm->page_table_lock);
2886 spin_unlock(&mm->page_table_lock);
2893 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2894 unsigned long address, unsigned int flags)
2899 struct page *page = NULL;
2900 struct page *pagecache_page = NULL;
2901 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2902 struct hstate *h = hstate_vma(vma);
2904 address &= huge_page_mask(h);
2906 ptep = huge_pte_offset(mm, address);
2908 entry = huge_ptep_get(ptep);
2909 if (unlikely(is_hugetlb_entry_migration(entry))) {
2910 migration_entry_wait_huge(mm, ptep);
2912 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2913 return VM_FAULT_HWPOISON_LARGE |
2914 VM_FAULT_SET_HINDEX(hstate_index(h));
2917 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2919 return VM_FAULT_OOM;
2922 * Serialize hugepage allocation and instantiation, so that we don't
2923 * get spurious allocation failures if two CPUs race to instantiate
2924 * the same page in the page cache.
2926 mutex_lock(&hugetlb_instantiation_mutex);
2927 entry = huge_ptep_get(ptep);
2928 if (huge_pte_none(entry)) {
2929 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2936 * If we are going to COW the mapping later, we examine the pending
2937 * reservations for this page now. This will ensure that any
2938 * allocations necessary to record that reservation occur outside the
2939 * spinlock. For private mappings, we also lookup the pagecache
2940 * page now as it is used to determine if a reservation has been
2943 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
2944 if (vma_needs_reservation(h, vma, address) < 0) {
2949 if (!(vma->vm_flags & VM_MAYSHARE))
2950 pagecache_page = hugetlbfs_pagecache_page(h,
2955 * hugetlb_cow() requires page locks of pte_page(entry) and
2956 * pagecache_page, so here we need take the former one
2957 * when page != pagecache_page or !pagecache_page.
2958 * Note that locking order is always pagecache_page -> page,
2959 * so no worry about deadlock.
2961 page = pte_page(entry);
2963 if (page != pagecache_page)
2966 spin_lock(&mm->page_table_lock);
2967 /* Check for a racing update before calling hugetlb_cow */
2968 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2969 goto out_page_table_lock;
2972 if (flags & FAULT_FLAG_WRITE) {
2973 if (!huge_pte_write(entry)) {
2974 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2976 goto out_page_table_lock;
2978 entry = huge_pte_mkdirty(entry);
2980 entry = pte_mkyoung(entry);
2981 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2982 flags & FAULT_FLAG_WRITE))
2983 update_mmu_cache(vma, address, ptep);
2985 out_page_table_lock:
2986 spin_unlock(&mm->page_table_lock);
2988 if (pagecache_page) {
2989 unlock_page(pagecache_page);
2990 put_page(pagecache_page);
2992 if (page != pagecache_page)
2997 mutex_unlock(&hugetlb_instantiation_mutex);
3002 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3003 struct page **pages, struct vm_area_struct **vmas,
3004 unsigned long *position, unsigned long *nr_pages,
3005 long i, unsigned int flags)
3007 unsigned long pfn_offset;
3008 unsigned long vaddr = *position;
3009 unsigned long remainder = *nr_pages;
3010 struct hstate *h = hstate_vma(vma);
3012 spin_lock(&mm->page_table_lock);
3013 while (vaddr < vma->vm_end && remainder) {
3019 * Some archs (sparc64, sh*) have multiple pte_ts to
3020 * each hugepage. We have to make sure we get the
3021 * first, for the page indexing below to work.
3023 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3024 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3027 * When coredumping, it suits get_dump_page if we just return
3028 * an error where there's an empty slot with no huge pagecache
3029 * to back it. This way, we avoid allocating a hugepage, and
3030 * the sparse dumpfile avoids allocating disk blocks, but its
3031 * huge holes still show up with zeroes where they need to be.
3033 if (absent && (flags & FOLL_DUMP) &&
3034 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3040 * We need call hugetlb_fault for both hugepages under migration
3041 * (in which case hugetlb_fault waits for the migration,) and
3042 * hwpoisoned hugepages (in which case we need to prevent the
3043 * caller from accessing to them.) In order to do this, we use
3044 * here is_swap_pte instead of is_hugetlb_entry_migration and
3045 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3046 * both cases, and because we can't follow correct pages
3047 * directly from any kind of swap entries.
3049 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3050 ((flags & FOLL_WRITE) &&
3051 !huge_pte_write(huge_ptep_get(pte)))) {
3054 spin_unlock(&mm->page_table_lock);
3055 ret = hugetlb_fault(mm, vma, vaddr,
3056 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3057 spin_lock(&mm->page_table_lock);
3058 if (!(ret & VM_FAULT_ERROR))
3065 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3066 page = pte_page(huge_ptep_get(pte));
3069 pages[i] = mem_map_offset(page, pfn_offset);
3080 if (vaddr < vma->vm_end && remainder &&
3081 pfn_offset < pages_per_huge_page(h)) {
3083 * We use pfn_offset to avoid touching the pageframes
3084 * of this compound page.
3089 spin_unlock(&mm->page_table_lock);
3090 *nr_pages = remainder;
3093 return i ? i : -EFAULT;
3096 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3097 unsigned long address, unsigned long end, pgprot_t newprot)
3099 struct mm_struct *mm = vma->vm_mm;
3100 unsigned long start = address;
3103 struct hstate *h = hstate_vma(vma);
3104 unsigned long pages = 0;
3106 BUG_ON(address >= end);
3107 flush_cache_range(vma, address, end);
3109 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3110 spin_lock(&mm->page_table_lock);
3111 for (; address < end; address += huge_page_size(h)) {
3112 ptep = huge_pte_offset(mm, address);
3115 if (huge_pmd_unshare(mm, &address, ptep)) {
3119 if (!huge_pte_none(huge_ptep_get(ptep))) {
3120 pte = huge_ptep_get_and_clear(mm, address, ptep);
3121 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3122 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3123 set_huge_pte_at(mm, address, ptep, pte);
3127 spin_unlock(&mm->page_table_lock);
3129 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3130 * may have cleared our pud entry and done put_page on the page table:
3131 * once we release i_mmap_mutex, another task can do the final put_page
3132 * and that page table be reused and filled with junk.
3134 flush_tlb_range(vma, start, end);
3135 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3137 return pages << h->order;
3140 int hugetlb_reserve_pages(struct inode *inode,
3142 struct vm_area_struct *vma,
3143 vm_flags_t vm_flags)
3146 struct hstate *h = hstate_inode(inode);
3147 struct hugepage_subpool *spool = subpool_inode(inode);
3150 * Only apply hugepage reservation if asked. At fault time, an
3151 * attempt will be made for VM_NORESERVE to allocate a page
3152 * without using reserves
3154 if (vm_flags & VM_NORESERVE)
3158 * Shared mappings base their reservation on the number of pages that
3159 * are already allocated on behalf of the file. Private mappings need
3160 * to reserve the full area even if read-only as mprotect() may be
3161 * called to make the mapping read-write. Assume !vma is a shm mapping
3163 if (!vma || vma->vm_flags & VM_MAYSHARE)
3164 chg = region_chg(&inode->i_mapping->private_list, from, to);
3166 struct resv_map *resv_map = resv_map_alloc();
3172 set_vma_resv_map(vma, resv_map);
3173 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3181 /* There must be enough pages in the subpool for the mapping */
3182 if (hugepage_subpool_get_pages(spool, chg)) {
3188 * Check enough hugepages are available for the reservation.
3189 * Hand the pages back to the subpool if there are not
3191 ret = hugetlb_acct_memory(h, chg);
3193 hugepage_subpool_put_pages(spool, chg);
3198 * Account for the reservations made. Shared mappings record regions
3199 * that have reservations as they are shared by multiple VMAs.
3200 * When the last VMA disappears, the region map says how much
3201 * the reservation was and the page cache tells how much of
3202 * the reservation was consumed. Private mappings are per-VMA and
3203 * only the consumed reservations are tracked. When the VMA
3204 * disappears, the original reservation is the VMA size and the
3205 * consumed reservations are stored in the map. Hence, nothing
3206 * else has to be done for private mappings here
3208 if (!vma || vma->vm_flags & VM_MAYSHARE)
3209 region_add(&inode->i_mapping->private_list, from, to);
3217 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3219 struct hstate *h = hstate_inode(inode);
3220 long chg = region_truncate(&inode->i_mapping->private_list, offset);
3221 struct hugepage_subpool *spool = subpool_inode(inode);
3223 spin_lock(&inode->i_lock);
3224 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3225 spin_unlock(&inode->i_lock);
3227 hugepage_subpool_put_pages(spool, (chg - freed));
3228 hugetlb_acct_memory(h, -(chg - freed));
3231 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3232 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3233 struct vm_area_struct *vma,
3234 unsigned long addr, pgoff_t idx)
3236 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3238 unsigned long sbase = saddr & PUD_MASK;
3239 unsigned long s_end = sbase + PUD_SIZE;
3241 /* Allow segments to share if only one is marked locked */
3242 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3243 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3246 * match the virtual addresses, permission and the alignment of the
3249 if (pmd_index(addr) != pmd_index(saddr) ||
3250 vm_flags != svm_flags ||
3251 sbase < svma->vm_start || svma->vm_end < s_end)
3257 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3259 unsigned long base = addr & PUD_MASK;
3260 unsigned long end = base + PUD_SIZE;
3263 * check on proper vm_flags and page table alignment
3265 if (vma->vm_flags & VM_MAYSHARE &&
3266 vma->vm_start <= base && end <= vma->vm_end)
3272 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3273 * and returns the corresponding pte. While this is not necessary for the
3274 * !shared pmd case because we can allocate the pmd later as well, it makes the
3275 * code much cleaner. pmd allocation is essential for the shared case because
3276 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3277 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3278 * bad pmd for sharing.
3280 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3282 struct vm_area_struct *vma = find_vma(mm, addr);
3283 struct address_space *mapping = vma->vm_file->f_mapping;
3284 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3286 struct vm_area_struct *svma;
3287 unsigned long saddr;
3291 if (!vma_shareable(vma, addr))
3292 return (pte_t *)pmd_alloc(mm, pud, addr);
3294 mutex_lock(&mapping->i_mmap_mutex);
3295 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3299 saddr = page_table_shareable(svma, vma, addr, idx);
3301 spte = huge_pte_offset(svma->vm_mm, saddr);
3303 get_page(virt_to_page(spte));
3312 spin_lock(&mm->page_table_lock);
3314 pud_populate(mm, pud,
3315 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3317 put_page(virt_to_page(spte));
3318 spin_unlock(&mm->page_table_lock);
3320 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3321 mutex_unlock(&mapping->i_mmap_mutex);
3326 * unmap huge page backed by shared pte.
3328 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3329 * indicated by page_count > 1, unmap is achieved by clearing pud and
3330 * decrementing the ref count. If count == 1, the pte page is not shared.
3332 * called with vma->vm_mm->page_table_lock held.
3334 * returns: 1 successfully unmapped a shared pte page
3335 * 0 the underlying pte page is not shared, or it is the last user
3337 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3339 pgd_t *pgd = pgd_offset(mm, *addr);
3340 pud_t *pud = pud_offset(pgd, *addr);
3342 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3343 if (page_count(virt_to_page(ptep)) == 1)
3347 put_page(virt_to_page(ptep));
3348 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3351 #define want_pmd_share() (1)
3352 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3353 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3357 #define want_pmd_share() (0)
3358 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3360 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3361 pte_t *huge_pte_alloc(struct mm_struct *mm,
3362 unsigned long addr, unsigned long sz)
3368 pgd = pgd_offset(mm, addr);
3369 pud = pud_alloc(mm, pgd, addr);
3371 if (sz == PUD_SIZE) {
3374 BUG_ON(sz != PMD_SIZE);
3375 if (want_pmd_share() && pud_none(*pud))
3376 pte = huge_pmd_share(mm, addr, pud);
3378 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3381 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3386 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3392 pgd = pgd_offset(mm, addr);
3393 if (pgd_present(*pgd)) {
3394 pud = pud_offset(pgd, addr);
3395 if (pud_present(*pud)) {
3397 return (pte_t *)pud;
3398 pmd = pmd_offset(pud, addr);
3401 return (pte_t *) pmd;
3405 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3406 pmd_t *pmd, int write)
3410 page = pte_page(*(pte_t *)pmd);
3412 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3417 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3418 pud_t *pud, int write)
3422 page = pte_page(*(pte_t *)pud);
3424 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3428 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3430 /* Can be overriden by architectures */
3431 __attribute__((weak)) struct page *
3432 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3433 pud_t *pud, int write)
3439 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3441 #ifdef CONFIG_MEMORY_FAILURE
3443 /* Should be called in hugetlb_lock */
3444 static int is_hugepage_on_freelist(struct page *hpage)
3448 struct hstate *h = page_hstate(hpage);
3449 int nid = page_to_nid(hpage);
3451 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3458 * This function is called from memory failure code.
3459 * Assume the caller holds page lock of the head page.
3461 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3463 struct hstate *h = page_hstate(hpage);
3464 int nid = page_to_nid(hpage);
3467 spin_lock(&hugetlb_lock);
3468 if (is_hugepage_on_freelist(hpage)) {
3470 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3471 * but dangling hpage->lru can trigger list-debug warnings
3472 * (this happens when we call unpoison_memory() on it),
3473 * so let it point to itself with list_del_init().
3475 list_del_init(&hpage->lru);
3476 set_page_refcounted(hpage);
3477 h->free_huge_pages--;
3478 h->free_huge_pages_node[nid]--;
3481 spin_unlock(&hugetlb_lock);
3486 bool isolate_huge_page(struct page *page, struct list_head *list)
3488 VM_BUG_ON(!PageHead(page));
3489 if (!get_page_unless_zero(page))
3491 spin_lock(&hugetlb_lock);
3492 list_move_tail(&page->lru, list);
3493 spin_unlock(&hugetlb_lock);
3497 void putback_active_hugepage(struct page *page)
3499 VM_BUG_ON(!PageHead(page));
3500 spin_lock(&hugetlb_lock);
3501 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3502 spin_unlock(&hugetlb_lock);
3506 bool is_hugepage_active(struct page *page)
3508 VM_BUG_ON(!PageHuge(page));
3510 * This function can be called for a tail page because the caller,
3511 * scan_movable_pages, scans through a given pfn-range which typically
3512 * covers one memory block. In systems using gigantic hugepage (1GB
3513 * for x86_64,) a hugepage is larger than a memory block, and we don't
3514 * support migrating such large hugepages for now, so return false
3515 * when called for tail pages.
3520 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3521 * so we should return false for them.
3523 if (unlikely(PageHWPoison(page)))
3525 return page_count(page) > 0;