2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
38 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
39 unsigned long hugepages_treat_as_movable;
41 int hugetlb_max_hstate __read_mostly;
42 unsigned int default_hstate_idx;
43 struct hstate hstates[HUGE_MAX_HSTATE];
45 __initdata LIST_HEAD(huge_boot_pages);
47 /* for command line parsing */
48 static struct hstate * __initdata parsed_hstate;
49 static unsigned long __initdata default_hstate_max_huge_pages;
50 static unsigned long __initdata default_hstate_size;
53 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
54 * free_huge_pages, and surplus_huge_pages.
56 DEFINE_SPINLOCK(hugetlb_lock);
59 * Serializes faults on the same logical page. This is used to
60 * prevent spurious OOMs when the hugepage pool is fully utilized.
62 static int num_fault_mutexes;
63 static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;
65 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
67 bool free = (spool->count == 0) && (spool->used_hpages == 0);
69 spin_unlock(&spool->lock);
71 /* If no pages are used, and no other handles to the subpool
72 * remain, free the subpool the subpool remain */
77 struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
79 struct hugepage_subpool *spool;
81 spool = kmalloc(sizeof(*spool), GFP_KERNEL);
85 spin_lock_init(&spool->lock);
87 spool->max_hpages = nr_blocks;
88 spool->used_hpages = 0;
93 void hugepage_put_subpool(struct hugepage_subpool *spool)
95 spin_lock(&spool->lock);
96 BUG_ON(!spool->count);
98 unlock_or_release_subpool(spool);
101 static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
109 spin_lock(&spool->lock);
110 if ((spool->used_hpages + delta) <= spool->max_hpages) {
111 spool->used_hpages += delta;
115 spin_unlock(&spool->lock);
120 static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
126 spin_lock(&spool->lock);
127 spool->used_hpages -= delta;
128 /* If hugetlbfs_put_super couldn't free spool due to
129 * an outstanding quota reference, free it now. */
130 unlock_or_release_subpool(spool);
133 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
135 return HUGETLBFS_SB(inode->i_sb)->spool;
138 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
140 return subpool_inode(file_inode(vma->vm_file));
144 * Region tracking -- allows tracking of reservations and instantiated pages
145 * across the pages in a mapping.
147 * The region data structures are embedded into a resv_map and
148 * protected by a resv_map's lock
151 struct list_head link;
156 static long region_add(struct resv_map *resv, long f, long t)
158 struct list_head *head = &resv->regions;
159 struct file_region *rg, *nrg, *trg;
161 spin_lock(&resv->lock);
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg, head, link)
167 /* Round our left edge to the current segment if it encloses us. */
171 /* Check for and consume any regions we now overlap with. */
173 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
174 if (&rg->link == head)
179 /* If this area reaches higher then extend our area to
180 * include it completely. If this is not the first area
181 * which we intend to reuse, free it. */
191 spin_unlock(&resv->lock);
195 static long region_chg(struct resv_map *resv, long f, long t)
197 struct list_head *head = &resv->regions;
198 struct file_region *rg, *nrg = NULL;
202 spin_lock(&resv->lock);
203 /* Locate the region we are before or in. */
204 list_for_each_entry(rg, head, link)
208 /* If we are below the current region then a new region is required.
209 * Subtle, allocate a new region at the position but make it zero
210 * size such that we can guarantee to record the reservation. */
211 if (&rg->link == head || t < rg->from) {
213 spin_unlock(&resv->lock);
214 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
220 INIT_LIST_HEAD(&nrg->link);
224 list_add(&nrg->link, rg->link.prev);
229 /* Round our left edge to the current segment if it encloses us. */
234 /* Check for and consume any regions we now overlap with. */
235 list_for_each_entry(rg, rg->link.prev, link) {
236 if (&rg->link == head)
241 /* We overlap with this area, if it extends further than
242 * us then we must extend ourselves. Account for its
243 * existing reservation. */
248 chg -= rg->to - rg->from;
252 spin_unlock(&resv->lock);
253 /* We already know we raced and no longer need the new region */
257 spin_unlock(&resv->lock);
261 static long region_truncate(struct resv_map *resv, long end)
263 struct list_head *head = &resv->regions;
264 struct file_region *rg, *trg;
267 spin_lock(&resv->lock);
268 /* Locate the region we are either in or before. */
269 list_for_each_entry(rg, head, link)
272 if (&rg->link == head)
275 /* If we are in the middle of a region then adjust it. */
276 if (end > rg->from) {
279 rg = list_entry(rg->link.next, typeof(*rg), link);
282 /* Drop any remaining regions. */
283 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
284 if (&rg->link == head)
286 chg += rg->to - rg->from;
292 spin_unlock(&resv->lock);
296 static long region_count(struct resv_map *resv, long f, long t)
298 struct list_head *head = &resv->regions;
299 struct file_region *rg;
302 spin_lock(&resv->lock);
303 /* Locate each segment we overlap with, and count that overlap. */
304 list_for_each_entry(rg, head, link) {
313 seg_from = max(rg->from, f);
314 seg_to = min(rg->to, t);
316 chg += seg_to - seg_from;
318 spin_unlock(&resv->lock);
324 * Convert the address within this vma to the page offset within
325 * the mapping, in pagecache page units; huge pages here.
327 static pgoff_t vma_hugecache_offset(struct hstate *h,
328 struct vm_area_struct *vma, unsigned long address)
330 return ((address - vma->vm_start) >> huge_page_shift(h)) +
331 (vma->vm_pgoff >> huge_page_order(h));
334 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
335 unsigned long address)
337 return vma_hugecache_offset(hstate_vma(vma), vma, address);
341 * Return the size of the pages allocated when backing a VMA. In the majority
342 * cases this will be same size as used by the page table entries.
344 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
346 struct hstate *hstate;
348 if (!is_vm_hugetlb_page(vma))
351 hstate = hstate_vma(vma);
353 return 1UL << huge_page_shift(hstate);
355 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
358 * Return the page size being used by the MMU to back a VMA. In the majority
359 * of cases, the page size used by the kernel matches the MMU size. On
360 * architectures where it differs, an architecture-specific version of this
361 * function is required.
363 #ifndef vma_mmu_pagesize
364 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
366 return vma_kernel_pagesize(vma);
371 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
372 * bits of the reservation map pointer, which are always clear due to
375 #define HPAGE_RESV_OWNER (1UL << 0)
376 #define HPAGE_RESV_UNMAPPED (1UL << 1)
377 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
380 * These helpers are used to track how many pages are reserved for
381 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
382 * is guaranteed to have their future faults succeed.
384 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
385 * the reserve counters are updated with the hugetlb_lock held. It is safe
386 * to reset the VMA at fork() time as it is not in use yet and there is no
387 * chance of the global counters getting corrupted as a result of the values.
389 * The private mapping reservation is represented in a subtly different
390 * manner to a shared mapping. A shared mapping has a region map associated
391 * with the underlying file, this region map represents the backing file
392 * pages which have ever had a reservation assigned which this persists even
393 * after the page is instantiated. A private mapping has a region map
394 * associated with the original mmap which is attached to all VMAs which
395 * reference it, this region map represents those offsets which have consumed
396 * reservation ie. where pages have been instantiated.
398 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
400 return (unsigned long)vma->vm_private_data;
403 static void set_vma_private_data(struct vm_area_struct *vma,
406 vma->vm_private_data = (void *)value;
409 struct resv_map *resv_map_alloc(void)
411 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
415 kref_init(&resv_map->refs);
416 spin_lock_init(&resv_map->lock);
417 INIT_LIST_HEAD(&resv_map->regions);
422 void resv_map_release(struct kref *ref)
424 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
426 /* Clear out any active regions before we release the map. */
427 region_truncate(resv_map, 0);
431 static inline struct resv_map *inode_resv_map(struct inode *inode)
433 return inode->i_mapping->private_data;
436 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
438 VM_BUG_ON(!is_vm_hugetlb_page(vma));
439 if (vma->vm_flags & VM_MAYSHARE) {
440 struct address_space *mapping = vma->vm_file->f_mapping;
441 struct inode *inode = mapping->host;
443 return inode_resv_map(inode);
446 return (struct resv_map *)(get_vma_private_data(vma) &
451 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
453 VM_BUG_ON(!is_vm_hugetlb_page(vma));
454 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
456 set_vma_private_data(vma, (get_vma_private_data(vma) &
457 HPAGE_RESV_MASK) | (unsigned long)map);
460 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
462 VM_BUG_ON(!is_vm_hugetlb_page(vma));
463 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
465 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
468 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
470 VM_BUG_ON(!is_vm_hugetlb_page(vma));
472 return (get_vma_private_data(vma) & flag) != 0;
475 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
476 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
478 VM_BUG_ON(!is_vm_hugetlb_page(vma));
479 if (!(vma->vm_flags & VM_MAYSHARE))
480 vma->vm_private_data = (void *)0;
483 /* Returns true if the VMA has associated reserve pages */
484 static int vma_has_reserves(struct vm_area_struct *vma, long chg)
486 if (vma->vm_flags & VM_NORESERVE) {
488 * This address is already reserved by other process(chg == 0),
489 * so, we should decrement reserved count. Without decrementing,
490 * reserve count remains after releasing inode, because this
491 * allocated page will go into page cache and is regarded as
492 * coming from reserved pool in releasing step. Currently, we
493 * don't have any other solution to deal with this situation
494 * properly, so add work-around here.
496 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
502 /* Shared mappings always use reserves */
503 if (vma->vm_flags & VM_MAYSHARE)
507 * Only the process that called mmap() has reserves for
510 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
516 static void enqueue_huge_page(struct hstate *h, struct page *page)
518 int nid = page_to_nid(page);
519 list_move(&page->lru, &h->hugepage_freelists[nid]);
520 h->free_huge_pages++;
521 h->free_huge_pages_node[nid]++;
524 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
528 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
529 if (!is_migrate_isolate_page(page))
532 * if 'non-isolated free hugepage' not found on the list,
533 * the allocation fails.
535 if (&h->hugepage_freelists[nid] == &page->lru)
537 list_move(&page->lru, &h->hugepage_activelist);
538 set_page_refcounted(page);
539 h->free_huge_pages--;
540 h->free_huge_pages_node[nid]--;
544 /* Movability of hugepages depends on migration support. */
545 static inline gfp_t htlb_alloc_mask(struct hstate *h)
547 if (hugepages_treat_as_movable || hugepage_migration_support(h))
548 return GFP_HIGHUSER_MOVABLE;
553 static struct page *dequeue_huge_page_vma(struct hstate *h,
554 struct vm_area_struct *vma,
555 unsigned long address, int avoid_reserve,
558 struct page *page = NULL;
559 struct mempolicy *mpol;
560 nodemask_t *nodemask;
561 struct zonelist *zonelist;
564 unsigned int cpuset_mems_cookie;
567 * A child process with MAP_PRIVATE mappings created by their parent
568 * have no page reserves. This check ensures that reservations are
569 * not "stolen". The child may still get SIGKILLed
571 if (!vma_has_reserves(vma, chg) &&
572 h->free_huge_pages - h->resv_huge_pages == 0)
575 /* If reserves cannot be used, ensure enough pages are in the pool */
576 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
580 cpuset_mems_cookie = read_mems_allowed_begin();
581 zonelist = huge_zonelist(vma, address,
582 htlb_alloc_mask(h), &mpol, &nodemask);
584 for_each_zone_zonelist_nodemask(zone, z, zonelist,
585 MAX_NR_ZONES - 1, nodemask) {
586 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) {
587 page = dequeue_huge_page_node(h, zone_to_nid(zone));
591 if (!vma_has_reserves(vma, chg))
594 SetPagePrivate(page);
595 h->resv_huge_pages--;
602 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
610 static void update_and_free_page(struct hstate *h, struct page *page)
614 VM_BUG_ON(h->order >= MAX_ORDER);
617 h->nr_huge_pages_node[page_to_nid(page)]--;
618 for (i = 0; i < pages_per_huge_page(h); i++) {
619 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
620 1 << PG_referenced | 1 << PG_dirty |
621 1 << PG_active | 1 << PG_reserved |
622 1 << PG_private | 1 << PG_writeback);
624 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
625 set_compound_page_dtor(page, NULL);
626 set_page_refcounted(page);
627 arch_release_hugepage(page);
628 __free_pages(page, huge_page_order(h));
631 struct hstate *size_to_hstate(unsigned long size)
636 if (huge_page_size(h) == size)
642 static void free_huge_page(struct page *page)
645 * Can't pass hstate in here because it is called from the
646 * compound page destructor.
648 struct hstate *h = page_hstate(page);
649 int nid = page_to_nid(page);
650 struct hugepage_subpool *spool =
651 (struct hugepage_subpool *)page_private(page);
652 bool restore_reserve;
654 set_page_private(page, 0);
655 page->mapping = NULL;
656 BUG_ON(page_count(page));
657 BUG_ON(page_mapcount(page));
658 restore_reserve = PagePrivate(page);
659 ClearPagePrivate(page);
661 spin_lock(&hugetlb_lock);
662 hugetlb_cgroup_uncharge_page(hstate_index(h),
663 pages_per_huge_page(h), page);
665 h->resv_huge_pages++;
667 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
668 /* remove the page from active list */
669 list_del(&page->lru);
670 update_and_free_page(h, page);
671 h->surplus_huge_pages--;
672 h->surplus_huge_pages_node[nid]--;
674 arch_clear_hugepage_flags(page);
675 enqueue_huge_page(h, page);
677 spin_unlock(&hugetlb_lock);
678 hugepage_subpool_put_pages(spool, 1);
681 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
683 INIT_LIST_HEAD(&page->lru);
684 set_compound_page_dtor(page, free_huge_page);
685 spin_lock(&hugetlb_lock);
686 set_hugetlb_cgroup(page, NULL);
688 h->nr_huge_pages_node[nid]++;
689 spin_unlock(&hugetlb_lock);
690 put_page(page); /* free it into the hugepage allocator */
693 static void __init prep_compound_gigantic_page(struct page *page,
697 int nr_pages = 1 << order;
698 struct page *p = page + 1;
700 /* we rely on prep_new_huge_page to set the destructor */
701 set_compound_order(page, order);
703 __ClearPageReserved(page);
704 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
707 * For gigantic hugepages allocated through bootmem at
708 * boot, it's safer to be consistent with the not-gigantic
709 * hugepages and clear the PG_reserved bit from all tail pages
710 * too. Otherwse drivers using get_user_pages() to access tail
711 * pages may get the reference counting wrong if they see
712 * PG_reserved set on a tail page (despite the head page not
713 * having PG_reserved set). Enforcing this consistency between
714 * head and tail pages allows drivers to optimize away a check
715 * on the head page when they need know if put_page() is needed
716 * after get_user_pages().
718 __ClearPageReserved(p);
719 set_page_count(p, 0);
720 p->first_page = page;
725 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
726 * transparent huge pages. See the PageTransHuge() documentation for more
729 int PageHuge(struct page *page)
731 if (!PageCompound(page))
734 page = compound_head(page);
735 return get_compound_page_dtor(page) == free_huge_page;
737 EXPORT_SYMBOL_GPL(PageHuge);
740 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
741 * normal or transparent huge pages.
743 int PageHeadHuge(struct page *page_head)
745 if (!PageHead(page_head))
748 return get_compound_page_dtor(page_head) == free_huge_page;
751 pgoff_t __basepage_index(struct page *page)
753 struct page *page_head = compound_head(page);
754 pgoff_t index = page_index(page_head);
755 unsigned long compound_idx;
757 if (!PageHuge(page_head))
758 return page_index(page);
760 if (compound_order(page_head) >= MAX_ORDER)
761 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
763 compound_idx = page - page_head;
765 return (index << compound_order(page_head)) + compound_idx;
768 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
772 if (h->order >= MAX_ORDER)
775 page = alloc_pages_exact_node(nid,
776 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
777 __GFP_REPEAT|__GFP_NOWARN,
780 if (arch_prepare_hugepage(page)) {
781 __free_pages(page, huge_page_order(h));
784 prep_new_huge_page(h, page, nid);
791 * common helper functions for hstate_next_node_to_{alloc|free}.
792 * We may have allocated or freed a huge page based on a different
793 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
794 * be outside of *nodes_allowed. Ensure that we use an allowed
795 * node for alloc or free.
797 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
799 nid = next_node(nid, *nodes_allowed);
800 if (nid == MAX_NUMNODES)
801 nid = first_node(*nodes_allowed);
802 VM_BUG_ON(nid >= MAX_NUMNODES);
807 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
809 if (!node_isset(nid, *nodes_allowed))
810 nid = next_node_allowed(nid, nodes_allowed);
815 * returns the previously saved node ["this node"] from which to
816 * allocate a persistent huge page for the pool and advance the
817 * next node from which to allocate, handling wrap at end of node
820 static int hstate_next_node_to_alloc(struct hstate *h,
821 nodemask_t *nodes_allowed)
825 VM_BUG_ON(!nodes_allowed);
827 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
828 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
834 * helper for free_pool_huge_page() - return the previously saved
835 * node ["this node"] from which to free a huge page. Advance the
836 * next node id whether or not we find a free huge page to free so
837 * that the next attempt to free addresses the next node.
839 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
843 VM_BUG_ON(!nodes_allowed);
845 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
846 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
851 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
852 for (nr_nodes = nodes_weight(*mask); \
854 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
857 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
858 for (nr_nodes = nodes_weight(*mask); \
860 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
863 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
869 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
870 page = alloc_fresh_huge_page_node(h, node);
878 count_vm_event(HTLB_BUDDY_PGALLOC);
880 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
886 * Free huge page from pool from next node to free.
887 * Attempt to keep persistent huge pages more or less
888 * balanced over allowed nodes.
889 * Called with hugetlb_lock locked.
891 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
897 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
899 * If we're returning unused surplus pages, only examine
900 * nodes with surplus pages.
902 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
903 !list_empty(&h->hugepage_freelists[node])) {
905 list_entry(h->hugepage_freelists[node].next,
907 list_del(&page->lru);
908 h->free_huge_pages--;
909 h->free_huge_pages_node[node]--;
911 h->surplus_huge_pages--;
912 h->surplus_huge_pages_node[node]--;
914 update_and_free_page(h, page);
924 * Dissolve a given free hugepage into free buddy pages. This function does
925 * nothing for in-use (including surplus) hugepages.
927 static void dissolve_free_huge_page(struct page *page)
929 spin_lock(&hugetlb_lock);
930 if (PageHuge(page) && !page_count(page)) {
931 struct hstate *h = page_hstate(page);
932 int nid = page_to_nid(page);
933 list_del(&page->lru);
934 h->free_huge_pages--;
935 h->free_huge_pages_node[nid]--;
936 update_and_free_page(h, page);
938 spin_unlock(&hugetlb_lock);
942 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
943 * make specified memory blocks removable from the system.
944 * Note that start_pfn should aligned with (minimum) hugepage size.
946 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
948 unsigned int order = 8 * sizeof(void *);
952 /* Set scan step to minimum hugepage size */
954 if (order > huge_page_order(h))
955 order = huge_page_order(h);
956 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
957 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
958 dissolve_free_huge_page(pfn_to_page(pfn));
961 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
966 if (h->order >= MAX_ORDER)
970 * Assume we will successfully allocate the surplus page to
971 * prevent racing processes from causing the surplus to exceed
974 * This however introduces a different race, where a process B
975 * tries to grow the static hugepage pool while alloc_pages() is
976 * called by process A. B will only examine the per-node
977 * counters in determining if surplus huge pages can be
978 * converted to normal huge pages in adjust_pool_surplus(). A
979 * won't be able to increment the per-node counter, until the
980 * lock is dropped by B, but B doesn't drop hugetlb_lock until
981 * no more huge pages can be converted from surplus to normal
982 * state (and doesn't try to convert again). Thus, we have a
983 * case where a surplus huge page exists, the pool is grown, and
984 * the surplus huge page still exists after, even though it
985 * should just have been converted to a normal huge page. This
986 * does not leak memory, though, as the hugepage will be freed
987 * once it is out of use. It also does not allow the counters to
988 * go out of whack in adjust_pool_surplus() as we don't modify
989 * the node values until we've gotten the hugepage and only the
990 * per-node value is checked there.
992 spin_lock(&hugetlb_lock);
993 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
994 spin_unlock(&hugetlb_lock);
998 h->surplus_huge_pages++;
1000 spin_unlock(&hugetlb_lock);
1002 if (nid == NUMA_NO_NODE)
1003 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
1004 __GFP_REPEAT|__GFP_NOWARN,
1005 huge_page_order(h));
1007 page = alloc_pages_exact_node(nid,
1008 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1009 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
1011 if (page && arch_prepare_hugepage(page)) {
1012 __free_pages(page, huge_page_order(h));
1016 spin_lock(&hugetlb_lock);
1018 INIT_LIST_HEAD(&page->lru);
1019 r_nid = page_to_nid(page);
1020 set_compound_page_dtor(page, free_huge_page);
1021 set_hugetlb_cgroup(page, NULL);
1023 * We incremented the global counters already
1025 h->nr_huge_pages_node[r_nid]++;
1026 h->surplus_huge_pages_node[r_nid]++;
1027 __count_vm_event(HTLB_BUDDY_PGALLOC);
1030 h->surplus_huge_pages--;
1031 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1033 spin_unlock(&hugetlb_lock);
1039 * This allocation function is useful in the context where vma is irrelevant.
1040 * E.g. soft-offlining uses this function because it only cares physical
1041 * address of error page.
1043 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1045 struct page *page = NULL;
1047 spin_lock(&hugetlb_lock);
1048 if (h->free_huge_pages - h->resv_huge_pages > 0)
1049 page = dequeue_huge_page_node(h, nid);
1050 spin_unlock(&hugetlb_lock);
1053 page = alloc_buddy_huge_page(h, nid);
1059 * Increase the hugetlb pool such that it can accommodate a reservation
1062 static int gather_surplus_pages(struct hstate *h, int delta)
1064 struct list_head surplus_list;
1065 struct page *page, *tmp;
1067 int needed, allocated;
1068 bool alloc_ok = true;
1070 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1072 h->resv_huge_pages += delta;
1077 INIT_LIST_HEAD(&surplus_list);
1081 spin_unlock(&hugetlb_lock);
1082 for (i = 0; i < needed; i++) {
1083 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1088 list_add(&page->lru, &surplus_list);
1093 * After retaking hugetlb_lock, we need to recalculate 'needed'
1094 * because either resv_huge_pages or free_huge_pages may have changed.
1096 spin_lock(&hugetlb_lock);
1097 needed = (h->resv_huge_pages + delta) -
1098 (h->free_huge_pages + allocated);
1103 * We were not able to allocate enough pages to
1104 * satisfy the entire reservation so we free what
1105 * we've allocated so far.
1110 * The surplus_list now contains _at_least_ the number of extra pages
1111 * needed to accommodate the reservation. Add the appropriate number
1112 * of pages to the hugetlb pool and free the extras back to the buddy
1113 * allocator. Commit the entire reservation here to prevent another
1114 * process from stealing the pages as they are added to the pool but
1115 * before they are reserved.
1117 needed += allocated;
1118 h->resv_huge_pages += delta;
1121 /* Free the needed pages to the hugetlb pool */
1122 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1126 * This page is now managed by the hugetlb allocator and has
1127 * no users -- drop the buddy allocator's reference.
1129 put_page_testzero(page);
1130 VM_BUG_ON_PAGE(page_count(page), page);
1131 enqueue_huge_page(h, page);
1134 spin_unlock(&hugetlb_lock);
1136 /* Free unnecessary surplus pages to the buddy allocator */
1137 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1139 spin_lock(&hugetlb_lock);
1145 * When releasing a hugetlb pool reservation, any surplus pages that were
1146 * allocated to satisfy the reservation must be explicitly freed if they were
1148 * Called with hugetlb_lock held.
1150 static void return_unused_surplus_pages(struct hstate *h,
1151 unsigned long unused_resv_pages)
1153 unsigned long nr_pages;
1155 /* Uncommit the reservation */
1156 h->resv_huge_pages -= unused_resv_pages;
1158 /* Cannot return gigantic pages currently */
1159 if (h->order >= MAX_ORDER)
1162 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1165 * We want to release as many surplus pages as possible, spread
1166 * evenly across all nodes with memory. Iterate across these nodes
1167 * until we can no longer free unreserved surplus pages. This occurs
1168 * when the nodes with surplus pages have no free pages.
1169 * free_pool_huge_page() will balance the the freed pages across the
1170 * on-line nodes with memory and will handle the hstate accounting.
1172 while (nr_pages--) {
1173 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1175 cond_resched_lock(&hugetlb_lock);
1180 * Determine if the huge page at addr within the vma has an associated
1181 * reservation. Where it does not we will need to logically increase
1182 * reservation and actually increase subpool usage before an allocation
1183 * can occur. Where any new reservation would be required the
1184 * reservation change is prepared, but not committed. Once the page
1185 * has been allocated from the subpool and instantiated the change should
1186 * be committed via vma_commit_reservation. No action is required on
1189 static long vma_needs_reservation(struct hstate *h,
1190 struct vm_area_struct *vma, unsigned long addr)
1192 struct resv_map *resv;
1196 resv = vma_resv_map(vma);
1200 idx = vma_hugecache_offset(h, vma, addr);
1201 chg = region_chg(resv, idx, idx + 1);
1203 if (vma->vm_flags & VM_MAYSHARE)
1206 return chg < 0 ? chg : 0;
1208 static void vma_commit_reservation(struct hstate *h,
1209 struct vm_area_struct *vma, unsigned long addr)
1211 struct resv_map *resv;
1214 resv = vma_resv_map(vma);
1218 idx = vma_hugecache_offset(h, vma, addr);
1219 region_add(resv, idx, idx + 1);
1222 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1223 unsigned long addr, int avoid_reserve)
1225 struct hugepage_subpool *spool = subpool_vma(vma);
1226 struct hstate *h = hstate_vma(vma);
1230 struct hugetlb_cgroup *h_cg;
1232 idx = hstate_index(h);
1234 * Processes that did not create the mapping will have no
1235 * reserves and will not have accounted against subpool
1236 * limit. Check that the subpool limit can be made before
1237 * satisfying the allocation MAP_NORESERVE mappings may also
1238 * need pages and subpool limit allocated allocated if no reserve
1241 chg = vma_needs_reservation(h, vma, addr);
1243 return ERR_PTR(-ENOMEM);
1244 if (chg || avoid_reserve)
1245 if (hugepage_subpool_get_pages(spool, 1))
1246 return ERR_PTR(-ENOSPC);
1248 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1250 if (chg || avoid_reserve)
1251 hugepage_subpool_put_pages(spool, 1);
1252 return ERR_PTR(-ENOSPC);
1254 spin_lock(&hugetlb_lock);
1255 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1257 spin_unlock(&hugetlb_lock);
1258 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1260 hugetlb_cgroup_uncharge_cgroup(idx,
1261 pages_per_huge_page(h),
1263 if (chg || avoid_reserve)
1264 hugepage_subpool_put_pages(spool, 1);
1265 return ERR_PTR(-ENOSPC);
1267 spin_lock(&hugetlb_lock);
1268 list_move(&page->lru, &h->hugepage_activelist);
1271 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1272 spin_unlock(&hugetlb_lock);
1274 set_page_private(page, (unsigned long)spool);
1276 vma_commit_reservation(h, vma, addr);
1281 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1282 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1283 * where no ERR_VALUE is expected to be returned.
1285 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1286 unsigned long addr, int avoid_reserve)
1288 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1294 int __weak alloc_bootmem_huge_page(struct hstate *h)
1296 struct huge_bootmem_page *m;
1299 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1302 addr = memblock_virt_alloc_try_nid_nopanic(
1303 huge_page_size(h), huge_page_size(h),
1304 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1307 * Use the beginning of the huge page to store the
1308 * huge_bootmem_page struct (until gather_bootmem
1309 * puts them into the mem_map).
1318 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1319 /* Put them into a private list first because mem_map is not up yet */
1320 list_add(&m->list, &huge_boot_pages);
1325 static void __init prep_compound_huge_page(struct page *page, int order)
1327 if (unlikely(order > (MAX_ORDER - 1)))
1328 prep_compound_gigantic_page(page, order);
1330 prep_compound_page(page, order);
1333 /* Put bootmem huge pages into the standard lists after mem_map is up */
1334 static void __init gather_bootmem_prealloc(void)
1336 struct huge_bootmem_page *m;
1338 list_for_each_entry(m, &huge_boot_pages, list) {
1339 struct hstate *h = m->hstate;
1342 #ifdef CONFIG_HIGHMEM
1343 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1344 memblock_free_late(__pa(m),
1345 sizeof(struct huge_bootmem_page));
1347 page = virt_to_page(m);
1349 WARN_ON(page_count(page) != 1);
1350 prep_compound_huge_page(page, h->order);
1351 WARN_ON(PageReserved(page));
1352 prep_new_huge_page(h, page, page_to_nid(page));
1354 * If we had gigantic hugepages allocated at boot time, we need
1355 * to restore the 'stolen' pages to totalram_pages in order to
1356 * fix confusing memory reports from free(1) and another
1357 * side-effects, like CommitLimit going negative.
1359 if (h->order > (MAX_ORDER - 1))
1360 adjust_managed_page_count(page, 1 << h->order);
1364 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1368 for (i = 0; i < h->max_huge_pages; ++i) {
1369 if (h->order >= MAX_ORDER) {
1370 if (!alloc_bootmem_huge_page(h))
1372 } else if (!alloc_fresh_huge_page(h,
1373 &node_states[N_MEMORY]))
1376 h->max_huge_pages = i;
1379 static void __init hugetlb_init_hstates(void)
1383 for_each_hstate(h) {
1384 /* oversize hugepages were init'ed in early boot */
1385 if (h->order < MAX_ORDER)
1386 hugetlb_hstate_alloc_pages(h);
1390 static char * __init memfmt(char *buf, unsigned long n)
1392 if (n >= (1UL << 30))
1393 sprintf(buf, "%lu GB", n >> 30);
1394 else if (n >= (1UL << 20))
1395 sprintf(buf, "%lu MB", n >> 20);
1397 sprintf(buf, "%lu KB", n >> 10);
1401 static void __init report_hugepages(void)
1405 for_each_hstate(h) {
1407 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1408 memfmt(buf, huge_page_size(h)),
1409 h->free_huge_pages);
1413 #ifdef CONFIG_HIGHMEM
1414 static void try_to_free_low(struct hstate *h, unsigned long count,
1415 nodemask_t *nodes_allowed)
1419 if (h->order >= MAX_ORDER)
1422 for_each_node_mask(i, *nodes_allowed) {
1423 struct page *page, *next;
1424 struct list_head *freel = &h->hugepage_freelists[i];
1425 list_for_each_entry_safe(page, next, freel, lru) {
1426 if (count >= h->nr_huge_pages)
1428 if (PageHighMem(page))
1430 list_del(&page->lru);
1431 update_and_free_page(h, page);
1432 h->free_huge_pages--;
1433 h->free_huge_pages_node[page_to_nid(page)]--;
1438 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1439 nodemask_t *nodes_allowed)
1445 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1446 * balanced by operating on them in a round-robin fashion.
1447 * Returns 1 if an adjustment was made.
1449 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1454 VM_BUG_ON(delta != -1 && delta != 1);
1457 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1458 if (h->surplus_huge_pages_node[node])
1462 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1463 if (h->surplus_huge_pages_node[node] <
1464 h->nr_huge_pages_node[node])
1471 h->surplus_huge_pages += delta;
1472 h->surplus_huge_pages_node[node] += delta;
1476 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1477 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1478 nodemask_t *nodes_allowed)
1480 unsigned long min_count, ret;
1482 if (h->order >= MAX_ORDER)
1483 return h->max_huge_pages;
1486 * Increase the pool size
1487 * First take pages out of surplus state. Then make up the
1488 * remaining difference by allocating fresh huge pages.
1490 * We might race with alloc_buddy_huge_page() here and be unable
1491 * to convert a surplus huge page to a normal huge page. That is
1492 * not critical, though, it just means the overall size of the
1493 * pool might be one hugepage larger than it needs to be, but
1494 * within all the constraints specified by the sysctls.
1496 spin_lock(&hugetlb_lock);
1497 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1498 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1502 while (count > persistent_huge_pages(h)) {
1504 * If this allocation races such that we no longer need the
1505 * page, free_huge_page will handle it by freeing the page
1506 * and reducing the surplus.
1508 spin_unlock(&hugetlb_lock);
1509 ret = alloc_fresh_huge_page(h, nodes_allowed);
1510 spin_lock(&hugetlb_lock);
1514 /* Bail for signals. Probably ctrl-c from user */
1515 if (signal_pending(current))
1520 * Decrease the pool size
1521 * First return free pages to the buddy allocator (being careful
1522 * to keep enough around to satisfy reservations). Then place
1523 * pages into surplus state as needed so the pool will shrink
1524 * to the desired size as pages become free.
1526 * By placing pages into the surplus state independent of the
1527 * overcommit value, we are allowing the surplus pool size to
1528 * exceed overcommit. There are few sane options here. Since
1529 * alloc_buddy_huge_page() is checking the global counter,
1530 * though, we'll note that we're not allowed to exceed surplus
1531 * and won't grow the pool anywhere else. Not until one of the
1532 * sysctls are changed, or the surplus pages go out of use.
1534 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1535 min_count = max(count, min_count);
1536 try_to_free_low(h, min_count, nodes_allowed);
1537 while (min_count < persistent_huge_pages(h)) {
1538 if (!free_pool_huge_page(h, nodes_allowed, 0))
1540 cond_resched_lock(&hugetlb_lock);
1542 while (count < persistent_huge_pages(h)) {
1543 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1547 ret = persistent_huge_pages(h);
1548 spin_unlock(&hugetlb_lock);
1552 #define HSTATE_ATTR_RO(_name) \
1553 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1555 #define HSTATE_ATTR(_name) \
1556 static struct kobj_attribute _name##_attr = \
1557 __ATTR(_name, 0644, _name##_show, _name##_store)
1559 static struct kobject *hugepages_kobj;
1560 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1562 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1564 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1568 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1569 if (hstate_kobjs[i] == kobj) {
1571 *nidp = NUMA_NO_NODE;
1575 return kobj_to_node_hstate(kobj, nidp);
1578 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1579 struct kobj_attribute *attr, char *buf)
1582 unsigned long nr_huge_pages;
1585 h = kobj_to_hstate(kobj, &nid);
1586 if (nid == NUMA_NO_NODE)
1587 nr_huge_pages = h->nr_huge_pages;
1589 nr_huge_pages = h->nr_huge_pages_node[nid];
1591 return sprintf(buf, "%lu\n", nr_huge_pages);
1594 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1595 struct kobject *kobj, struct kobj_attribute *attr,
1596 const char *buf, size_t len)
1600 unsigned long count;
1602 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1604 err = kstrtoul(buf, 10, &count);
1608 h = kobj_to_hstate(kobj, &nid);
1609 if (h->order >= MAX_ORDER) {
1614 if (nid == NUMA_NO_NODE) {
1616 * global hstate attribute
1618 if (!(obey_mempolicy &&
1619 init_nodemask_of_mempolicy(nodes_allowed))) {
1620 NODEMASK_FREE(nodes_allowed);
1621 nodes_allowed = &node_states[N_MEMORY];
1623 } else if (nodes_allowed) {
1625 * per node hstate attribute: adjust count to global,
1626 * but restrict alloc/free to the specified node.
1628 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1629 init_nodemask_of_node(nodes_allowed, nid);
1631 nodes_allowed = &node_states[N_MEMORY];
1633 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1635 if (nodes_allowed != &node_states[N_MEMORY])
1636 NODEMASK_FREE(nodes_allowed);
1640 NODEMASK_FREE(nodes_allowed);
1644 static ssize_t nr_hugepages_show(struct kobject *kobj,
1645 struct kobj_attribute *attr, char *buf)
1647 return nr_hugepages_show_common(kobj, attr, buf);
1650 static ssize_t nr_hugepages_store(struct kobject *kobj,
1651 struct kobj_attribute *attr, const char *buf, size_t len)
1653 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1655 HSTATE_ATTR(nr_hugepages);
1660 * hstate attribute for optionally mempolicy-based constraint on persistent
1661 * huge page alloc/free.
1663 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1664 struct kobj_attribute *attr, char *buf)
1666 return nr_hugepages_show_common(kobj, attr, buf);
1669 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1670 struct kobj_attribute *attr, const char *buf, size_t len)
1672 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1674 HSTATE_ATTR(nr_hugepages_mempolicy);
1678 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1679 struct kobj_attribute *attr, char *buf)
1681 struct hstate *h = kobj_to_hstate(kobj, NULL);
1682 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1685 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1686 struct kobj_attribute *attr, const char *buf, size_t count)
1689 unsigned long input;
1690 struct hstate *h = kobj_to_hstate(kobj, NULL);
1692 if (h->order >= MAX_ORDER)
1695 err = kstrtoul(buf, 10, &input);
1699 spin_lock(&hugetlb_lock);
1700 h->nr_overcommit_huge_pages = input;
1701 spin_unlock(&hugetlb_lock);
1705 HSTATE_ATTR(nr_overcommit_hugepages);
1707 static ssize_t free_hugepages_show(struct kobject *kobj,
1708 struct kobj_attribute *attr, char *buf)
1711 unsigned long free_huge_pages;
1714 h = kobj_to_hstate(kobj, &nid);
1715 if (nid == NUMA_NO_NODE)
1716 free_huge_pages = h->free_huge_pages;
1718 free_huge_pages = h->free_huge_pages_node[nid];
1720 return sprintf(buf, "%lu\n", free_huge_pages);
1722 HSTATE_ATTR_RO(free_hugepages);
1724 static ssize_t resv_hugepages_show(struct kobject *kobj,
1725 struct kobj_attribute *attr, char *buf)
1727 struct hstate *h = kobj_to_hstate(kobj, NULL);
1728 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1730 HSTATE_ATTR_RO(resv_hugepages);
1732 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1733 struct kobj_attribute *attr, char *buf)
1736 unsigned long surplus_huge_pages;
1739 h = kobj_to_hstate(kobj, &nid);
1740 if (nid == NUMA_NO_NODE)
1741 surplus_huge_pages = h->surplus_huge_pages;
1743 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1745 return sprintf(buf, "%lu\n", surplus_huge_pages);
1747 HSTATE_ATTR_RO(surplus_hugepages);
1749 static struct attribute *hstate_attrs[] = {
1750 &nr_hugepages_attr.attr,
1751 &nr_overcommit_hugepages_attr.attr,
1752 &free_hugepages_attr.attr,
1753 &resv_hugepages_attr.attr,
1754 &surplus_hugepages_attr.attr,
1756 &nr_hugepages_mempolicy_attr.attr,
1761 static struct attribute_group hstate_attr_group = {
1762 .attrs = hstate_attrs,
1765 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1766 struct kobject **hstate_kobjs,
1767 struct attribute_group *hstate_attr_group)
1770 int hi = hstate_index(h);
1772 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1773 if (!hstate_kobjs[hi])
1776 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1778 kobject_put(hstate_kobjs[hi]);
1783 static void __init hugetlb_sysfs_init(void)
1788 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1789 if (!hugepages_kobj)
1792 for_each_hstate(h) {
1793 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1794 hstate_kobjs, &hstate_attr_group);
1796 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1803 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1804 * with node devices in node_devices[] using a parallel array. The array
1805 * index of a node device or _hstate == node id.
1806 * This is here to avoid any static dependency of the node device driver, in
1807 * the base kernel, on the hugetlb module.
1809 struct node_hstate {
1810 struct kobject *hugepages_kobj;
1811 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1813 struct node_hstate node_hstates[MAX_NUMNODES];
1816 * A subset of global hstate attributes for node devices
1818 static struct attribute *per_node_hstate_attrs[] = {
1819 &nr_hugepages_attr.attr,
1820 &free_hugepages_attr.attr,
1821 &surplus_hugepages_attr.attr,
1825 static struct attribute_group per_node_hstate_attr_group = {
1826 .attrs = per_node_hstate_attrs,
1830 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1831 * Returns node id via non-NULL nidp.
1833 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1837 for (nid = 0; nid < nr_node_ids; nid++) {
1838 struct node_hstate *nhs = &node_hstates[nid];
1840 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1841 if (nhs->hstate_kobjs[i] == kobj) {
1853 * Unregister hstate attributes from a single node device.
1854 * No-op if no hstate attributes attached.
1856 static void hugetlb_unregister_node(struct node *node)
1859 struct node_hstate *nhs = &node_hstates[node->dev.id];
1861 if (!nhs->hugepages_kobj)
1862 return; /* no hstate attributes */
1864 for_each_hstate(h) {
1865 int idx = hstate_index(h);
1866 if (nhs->hstate_kobjs[idx]) {
1867 kobject_put(nhs->hstate_kobjs[idx]);
1868 nhs->hstate_kobjs[idx] = NULL;
1872 kobject_put(nhs->hugepages_kobj);
1873 nhs->hugepages_kobj = NULL;
1877 * hugetlb module exit: unregister hstate attributes from node devices
1880 static void hugetlb_unregister_all_nodes(void)
1885 * disable node device registrations.
1887 register_hugetlbfs_with_node(NULL, NULL);
1890 * remove hstate attributes from any nodes that have them.
1892 for (nid = 0; nid < nr_node_ids; nid++)
1893 hugetlb_unregister_node(node_devices[nid]);
1897 * Register hstate attributes for a single node device.
1898 * No-op if attributes already registered.
1900 static void hugetlb_register_node(struct node *node)
1903 struct node_hstate *nhs = &node_hstates[node->dev.id];
1906 if (nhs->hugepages_kobj)
1907 return; /* already allocated */
1909 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1911 if (!nhs->hugepages_kobj)
1914 for_each_hstate(h) {
1915 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1917 &per_node_hstate_attr_group);
1919 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1920 h->name, node->dev.id);
1921 hugetlb_unregister_node(node);
1928 * hugetlb init time: register hstate attributes for all registered node
1929 * devices of nodes that have memory. All on-line nodes should have
1930 * registered their associated device by this time.
1932 static void hugetlb_register_all_nodes(void)
1936 for_each_node_state(nid, N_MEMORY) {
1937 struct node *node = node_devices[nid];
1938 if (node->dev.id == nid)
1939 hugetlb_register_node(node);
1943 * Let the node device driver know we're here so it can
1944 * [un]register hstate attributes on node hotplug.
1946 register_hugetlbfs_with_node(hugetlb_register_node,
1947 hugetlb_unregister_node);
1949 #else /* !CONFIG_NUMA */
1951 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1959 static void hugetlb_unregister_all_nodes(void) { }
1961 static void hugetlb_register_all_nodes(void) { }
1965 static void __exit hugetlb_exit(void)
1969 hugetlb_unregister_all_nodes();
1971 for_each_hstate(h) {
1972 kobject_put(hstate_kobjs[hstate_index(h)]);
1975 kobject_put(hugepages_kobj);
1976 kfree(htlb_fault_mutex_table);
1978 module_exit(hugetlb_exit);
1980 static int __init hugetlb_init(void)
1984 /* Some platform decide whether they support huge pages at boot
1985 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1986 * there is no such support
1988 if (HPAGE_SHIFT == 0)
1991 if (!size_to_hstate(default_hstate_size)) {
1992 default_hstate_size = HPAGE_SIZE;
1993 if (!size_to_hstate(default_hstate_size))
1994 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1996 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1997 if (default_hstate_max_huge_pages)
1998 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2000 hugetlb_init_hstates();
2001 gather_bootmem_prealloc();
2004 hugetlb_sysfs_init();
2005 hugetlb_register_all_nodes();
2006 hugetlb_cgroup_file_init();
2009 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2011 num_fault_mutexes = 1;
2013 htlb_fault_mutex_table =
2014 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2015 BUG_ON(!htlb_fault_mutex_table);
2017 for (i = 0; i < num_fault_mutexes; i++)
2018 mutex_init(&htlb_fault_mutex_table[i]);
2021 module_init(hugetlb_init);
2023 /* Should be called on processing a hugepagesz=... option */
2024 void __init hugetlb_add_hstate(unsigned order)
2029 if (size_to_hstate(PAGE_SIZE << order)) {
2030 pr_warning("hugepagesz= specified twice, ignoring\n");
2033 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2035 h = &hstates[hugetlb_max_hstate++];
2037 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2038 h->nr_huge_pages = 0;
2039 h->free_huge_pages = 0;
2040 for (i = 0; i < MAX_NUMNODES; ++i)
2041 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2042 INIT_LIST_HEAD(&h->hugepage_activelist);
2043 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2044 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2045 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2046 huge_page_size(h)/1024);
2051 static int __init hugetlb_nrpages_setup(char *s)
2054 static unsigned long *last_mhp;
2057 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2058 * so this hugepages= parameter goes to the "default hstate".
2060 if (!hugetlb_max_hstate)
2061 mhp = &default_hstate_max_huge_pages;
2063 mhp = &parsed_hstate->max_huge_pages;
2065 if (mhp == last_mhp) {
2066 pr_warning("hugepages= specified twice without "
2067 "interleaving hugepagesz=, ignoring\n");
2071 if (sscanf(s, "%lu", mhp) <= 0)
2075 * Global state is always initialized later in hugetlb_init.
2076 * But we need to allocate >= MAX_ORDER hstates here early to still
2077 * use the bootmem allocator.
2079 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2080 hugetlb_hstate_alloc_pages(parsed_hstate);
2086 __setup("hugepages=", hugetlb_nrpages_setup);
2088 static int __init hugetlb_default_setup(char *s)
2090 default_hstate_size = memparse(s, &s);
2093 __setup("default_hugepagesz=", hugetlb_default_setup);
2095 static unsigned int cpuset_mems_nr(unsigned int *array)
2098 unsigned int nr = 0;
2100 for_each_node_mask(node, cpuset_current_mems_allowed)
2106 #ifdef CONFIG_SYSCTL
2107 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2108 struct ctl_table *table, int write,
2109 void __user *buffer, size_t *length, loff_t *ppos)
2111 struct hstate *h = &default_hstate;
2115 tmp = h->max_huge_pages;
2117 if (write && h->order >= MAX_ORDER)
2121 table->maxlen = sizeof(unsigned long);
2122 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2127 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2128 GFP_KERNEL | __GFP_NORETRY);
2129 if (!(obey_mempolicy &&
2130 init_nodemask_of_mempolicy(nodes_allowed))) {
2131 NODEMASK_FREE(nodes_allowed);
2132 nodes_allowed = &node_states[N_MEMORY];
2134 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2136 if (nodes_allowed != &node_states[N_MEMORY])
2137 NODEMASK_FREE(nodes_allowed);
2143 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2144 void __user *buffer, size_t *length, loff_t *ppos)
2147 return hugetlb_sysctl_handler_common(false, table, write,
2148 buffer, length, ppos);
2152 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2153 void __user *buffer, size_t *length, loff_t *ppos)
2155 return hugetlb_sysctl_handler_common(true, table, write,
2156 buffer, length, ppos);
2158 #endif /* CONFIG_NUMA */
2160 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2161 void __user *buffer,
2162 size_t *length, loff_t *ppos)
2164 struct hstate *h = &default_hstate;
2168 tmp = h->nr_overcommit_huge_pages;
2170 if (write && h->order >= MAX_ORDER)
2174 table->maxlen = sizeof(unsigned long);
2175 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2180 spin_lock(&hugetlb_lock);
2181 h->nr_overcommit_huge_pages = tmp;
2182 spin_unlock(&hugetlb_lock);
2188 #endif /* CONFIG_SYSCTL */
2190 void hugetlb_report_meminfo(struct seq_file *m)
2192 struct hstate *h = &default_hstate;
2194 "HugePages_Total: %5lu\n"
2195 "HugePages_Free: %5lu\n"
2196 "HugePages_Rsvd: %5lu\n"
2197 "HugePages_Surp: %5lu\n"
2198 "Hugepagesize: %8lu kB\n",
2202 h->surplus_huge_pages,
2203 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2206 int hugetlb_report_node_meminfo(int nid, char *buf)
2208 struct hstate *h = &default_hstate;
2210 "Node %d HugePages_Total: %5u\n"
2211 "Node %d HugePages_Free: %5u\n"
2212 "Node %d HugePages_Surp: %5u\n",
2213 nid, h->nr_huge_pages_node[nid],
2214 nid, h->free_huge_pages_node[nid],
2215 nid, h->surplus_huge_pages_node[nid]);
2218 void hugetlb_show_meminfo(void)
2223 for_each_node_state(nid, N_MEMORY)
2225 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2227 h->nr_huge_pages_node[nid],
2228 h->free_huge_pages_node[nid],
2229 h->surplus_huge_pages_node[nid],
2230 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2233 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2234 unsigned long hugetlb_total_pages(void)
2237 unsigned long nr_total_pages = 0;
2240 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2241 return nr_total_pages;
2244 static int hugetlb_acct_memory(struct hstate *h, long delta)
2248 spin_lock(&hugetlb_lock);
2250 * When cpuset is configured, it breaks the strict hugetlb page
2251 * reservation as the accounting is done on a global variable. Such
2252 * reservation is completely rubbish in the presence of cpuset because
2253 * the reservation is not checked against page availability for the
2254 * current cpuset. Application can still potentially OOM'ed by kernel
2255 * with lack of free htlb page in cpuset that the task is in.
2256 * Attempt to enforce strict accounting with cpuset is almost
2257 * impossible (or too ugly) because cpuset is too fluid that
2258 * task or memory node can be dynamically moved between cpusets.
2260 * The change of semantics for shared hugetlb mapping with cpuset is
2261 * undesirable. However, in order to preserve some of the semantics,
2262 * we fall back to check against current free page availability as
2263 * a best attempt and hopefully to minimize the impact of changing
2264 * semantics that cpuset has.
2267 if (gather_surplus_pages(h, delta) < 0)
2270 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2271 return_unused_surplus_pages(h, delta);
2278 return_unused_surplus_pages(h, (unsigned long) -delta);
2281 spin_unlock(&hugetlb_lock);
2285 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2287 struct resv_map *resv = vma_resv_map(vma);
2290 * This new VMA should share its siblings reservation map if present.
2291 * The VMA will only ever have a valid reservation map pointer where
2292 * it is being copied for another still existing VMA. As that VMA
2293 * has a reference to the reservation map it cannot disappear until
2294 * after this open call completes. It is therefore safe to take a
2295 * new reference here without additional locking.
2297 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2298 kref_get(&resv->refs);
2301 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2303 struct hstate *h = hstate_vma(vma);
2304 struct resv_map *resv = vma_resv_map(vma);
2305 struct hugepage_subpool *spool = subpool_vma(vma);
2306 unsigned long reserve, start, end;
2308 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2311 start = vma_hugecache_offset(h, vma, vma->vm_start);
2312 end = vma_hugecache_offset(h, vma, vma->vm_end);
2314 reserve = (end - start) - region_count(resv, start, end);
2316 kref_put(&resv->refs, resv_map_release);
2319 hugetlb_acct_memory(h, -reserve);
2320 hugepage_subpool_put_pages(spool, reserve);
2325 * We cannot handle pagefaults against hugetlb pages at all. They cause
2326 * handle_mm_fault() to try to instantiate regular-sized pages in the
2327 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2330 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2336 const struct vm_operations_struct hugetlb_vm_ops = {
2337 .fault = hugetlb_vm_op_fault,
2338 .open = hugetlb_vm_op_open,
2339 .close = hugetlb_vm_op_close,
2342 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2348 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2349 vma->vm_page_prot)));
2351 entry = huge_pte_wrprotect(mk_huge_pte(page,
2352 vma->vm_page_prot));
2354 entry = pte_mkyoung(entry);
2355 entry = pte_mkhuge(entry);
2356 entry = arch_make_huge_pte(entry, vma, page, writable);
2361 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2362 unsigned long address, pte_t *ptep)
2366 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2367 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2368 update_mmu_cache(vma, address, ptep);
2372 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2373 struct vm_area_struct *vma)
2375 pte_t *src_pte, *dst_pte, entry;
2376 struct page *ptepage;
2379 struct hstate *h = hstate_vma(vma);
2380 unsigned long sz = huge_page_size(h);
2381 unsigned long mmun_start; /* For mmu_notifiers */
2382 unsigned long mmun_end; /* For mmu_notifiers */
2385 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2387 mmun_start = vma->vm_start;
2388 mmun_end = vma->vm_end;
2390 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
2392 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2393 spinlock_t *src_ptl, *dst_ptl;
2394 src_pte = huge_pte_offset(src, addr);
2397 dst_pte = huge_pte_alloc(dst, addr, sz);
2403 /* If the pagetables are shared don't copy or take references */
2404 if (dst_pte == src_pte)
2407 dst_ptl = huge_pte_lock(h, dst, dst_pte);
2408 src_ptl = huge_pte_lockptr(h, src, src_pte);
2409 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2410 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2412 huge_ptep_set_wrprotect(src, addr, src_pte);
2413 entry = huge_ptep_get(src_pte);
2414 ptepage = pte_page(entry);
2416 page_dup_rmap(ptepage);
2417 set_huge_pte_at(dst, addr, dst_pte, entry);
2419 spin_unlock(src_ptl);
2420 spin_unlock(dst_ptl);
2424 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
2429 static int is_hugetlb_entry_migration(pte_t pte)
2433 if (huge_pte_none(pte) || pte_present(pte))
2435 swp = pte_to_swp_entry(pte);
2436 if (non_swap_entry(swp) && is_migration_entry(swp))
2442 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2446 if (huge_pte_none(pte) || pte_present(pte))
2448 swp = pte_to_swp_entry(pte);
2449 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2455 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2456 unsigned long start, unsigned long end,
2457 struct page *ref_page)
2459 int force_flush = 0;
2460 struct mm_struct *mm = vma->vm_mm;
2461 unsigned long address;
2466 struct hstate *h = hstate_vma(vma);
2467 unsigned long sz = huge_page_size(h);
2468 const unsigned long mmun_start = start; /* For mmu_notifiers */
2469 const unsigned long mmun_end = end; /* For mmu_notifiers */
2471 WARN_ON(!is_vm_hugetlb_page(vma));
2472 BUG_ON(start & ~huge_page_mask(h));
2473 BUG_ON(end & ~huge_page_mask(h));
2475 tlb_start_vma(tlb, vma);
2476 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2478 for (address = start; address < end; address += sz) {
2479 ptep = huge_pte_offset(mm, address);
2483 ptl = huge_pte_lock(h, mm, ptep);
2484 if (huge_pmd_unshare(mm, &address, ptep))
2487 pte = huge_ptep_get(ptep);
2488 if (huge_pte_none(pte))
2492 * HWPoisoned hugepage is already unmapped and dropped reference
2494 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2495 huge_pte_clear(mm, address, ptep);
2499 page = pte_page(pte);
2501 * If a reference page is supplied, it is because a specific
2502 * page is being unmapped, not a range. Ensure the page we
2503 * are about to unmap is the actual page of interest.
2506 if (page != ref_page)
2510 * Mark the VMA as having unmapped its page so that
2511 * future faults in this VMA will fail rather than
2512 * looking like data was lost
2514 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2517 pte = huge_ptep_get_and_clear(mm, address, ptep);
2518 tlb_remove_tlb_entry(tlb, ptep, address);
2519 if (huge_pte_dirty(pte))
2520 set_page_dirty(page);
2522 page_remove_rmap(page);
2523 force_flush = !__tlb_remove_page(tlb, page);
2528 /* Bail out after unmapping reference page if supplied */
2537 * mmu_gather ran out of room to batch pages, we break out of
2538 * the PTE lock to avoid doing the potential expensive TLB invalidate
2539 * and page-free while holding it.
2544 if (address < end && !ref_page)
2547 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2548 tlb_end_vma(tlb, vma);
2551 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2552 struct vm_area_struct *vma, unsigned long start,
2553 unsigned long end, struct page *ref_page)
2555 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2558 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2559 * test will fail on a vma being torn down, and not grab a page table
2560 * on its way out. We're lucky that the flag has such an appropriate
2561 * name, and can in fact be safely cleared here. We could clear it
2562 * before the __unmap_hugepage_range above, but all that's necessary
2563 * is to clear it before releasing the i_mmap_mutex. This works
2564 * because in the context this is called, the VMA is about to be
2565 * destroyed and the i_mmap_mutex is held.
2567 vma->vm_flags &= ~VM_MAYSHARE;
2570 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2571 unsigned long end, struct page *ref_page)
2573 struct mm_struct *mm;
2574 struct mmu_gather tlb;
2578 tlb_gather_mmu(&tlb, mm, start, end);
2579 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2580 tlb_finish_mmu(&tlb, start, end);
2584 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2585 * mappping it owns the reserve page for. The intention is to unmap the page
2586 * from other VMAs and let the children be SIGKILLed if they are faulting the
2589 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2590 struct page *page, unsigned long address)
2592 struct hstate *h = hstate_vma(vma);
2593 struct vm_area_struct *iter_vma;
2594 struct address_space *mapping;
2598 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2599 * from page cache lookup which is in HPAGE_SIZE units.
2601 address = address & huge_page_mask(h);
2602 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2604 mapping = file_inode(vma->vm_file)->i_mapping;
2607 * Take the mapping lock for the duration of the table walk. As
2608 * this mapping should be shared between all the VMAs,
2609 * __unmap_hugepage_range() is called as the lock is already held
2611 mutex_lock(&mapping->i_mmap_mutex);
2612 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2613 /* Do not unmap the current VMA */
2614 if (iter_vma == vma)
2618 * Unmap the page from other VMAs without their own reserves.
2619 * They get marked to be SIGKILLed if they fault in these
2620 * areas. This is because a future no-page fault on this VMA
2621 * could insert a zeroed page instead of the data existing
2622 * from the time of fork. This would look like data corruption
2624 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2625 unmap_hugepage_range(iter_vma, address,
2626 address + huge_page_size(h), page);
2628 mutex_unlock(&mapping->i_mmap_mutex);
2634 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2635 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2636 * cannot race with other handlers or page migration.
2637 * Keep the pte_same checks anyway to make transition from the mutex easier.
2639 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2640 unsigned long address, pte_t *ptep, pte_t pte,
2641 struct page *pagecache_page, spinlock_t *ptl)
2643 struct hstate *h = hstate_vma(vma);
2644 struct page *old_page, *new_page;
2645 int outside_reserve = 0;
2646 unsigned long mmun_start; /* For mmu_notifiers */
2647 unsigned long mmun_end; /* For mmu_notifiers */
2649 old_page = pte_page(pte);
2652 /* If no-one else is actually using this page, avoid the copy
2653 * and just make the page writable */
2654 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2655 page_move_anon_rmap(old_page, vma, address);
2656 set_huge_ptep_writable(vma, address, ptep);
2661 * If the process that created a MAP_PRIVATE mapping is about to
2662 * perform a COW due to a shared page count, attempt to satisfy
2663 * the allocation without using the existing reserves. The pagecache
2664 * page is used to determine if the reserve at this address was
2665 * consumed or not. If reserves were used, a partial faulted mapping
2666 * at the time of fork() could consume its reserves on COW instead
2667 * of the full address range.
2669 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2670 old_page != pagecache_page)
2671 outside_reserve = 1;
2673 page_cache_get(old_page);
2675 /* Drop page table lock as buddy allocator may be called */
2677 new_page = alloc_huge_page(vma, address, outside_reserve);
2679 if (IS_ERR(new_page)) {
2680 long err = PTR_ERR(new_page);
2681 page_cache_release(old_page);
2684 * If a process owning a MAP_PRIVATE mapping fails to COW,
2685 * it is due to references held by a child and an insufficient
2686 * huge page pool. To guarantee the original mappers
2687 * reliability, unmap the page from child processes. The child
2688 * may get SIGKILLed if it later faults.
2690 if (outside_reserve) {
2691 BUG_ON(huge_pte_none(pte));
2692 if (unmap_ref_private(mm, vma, old_page, address)) {
2693 BUG_ON(huge_pte_none(pte));
2695 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2697 pte_same(huge_ptep_get(ptep), pte)))
2698 goto retry_avoidcopy;
2700 * race occurs while re-acquiring page table
2701 * lock, and our job is done.
2708 /* Caller expects lock to be held */
2711 return VM_FAULT_OOM;
2713 return VM_FAULT_SIGBUS;
2717 * When the original hugepage is shared one, it does not have
2718 * anon_vma prepared.
2720 if (unlikely(anon_vma_prepare(vma))) {
2721 page_cache_release(new_page);
2722 page_cache_release(old_page);
2723 /* Caller expects lock to be held */
2725 return VM_FAULT_OOM;
2728 copy_user_huge_page(new_page, old_page, address, vma,
2729 pages_per_huge_page(h));
2730 __SetPageUptodate(new_page);
2732 mmun_start = address & huge_page_mask(h);
2733 mmun_end = mmun_start + huge_page_size(h);
2734 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2736 * Retake the page table lock to check for racing updates
2737 * before the page tables are altered
2740 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2741 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
2742 ClearPagePrivate(new_page);
2745 huge_ptep_clear_flush(vma, address, ptep);
2746 set_huge_pte_at(mm, address, ptep,
2747 make_huge_pte(vma, new_page, 1));
2748 page_remove_rmap(old_page);
2749 hugepage_add_new_anon_rmap(new_page, vma, address);
2750 /* Make the old page be freed below */
2751 new_page = old_page;
2754 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2755 page_cache_release(new_page);
2756 page_cache_release(old_page);
2758 /* Caller expects lock to be held */
2763 /* Return the pagecache page at a given address within a VMA */
2764 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2765 struct vm_area_struct *vma, unsigned long address)
2767 struct address_space *mapping;
2770 mapping = vma->vm_file->f_mapping;
2771 idx = vma_hugecache_offset(h, vma, address);
2773 return find_lock_page(mapping, idx);
2777 * Return whether there is a pagecache page to back given address within VMA.
2778 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2780 static bool hugetlbfs_pagecache_present(struct hstate *h,
2781 struct vm_area_struct *vma, unsigned long address)
2783 struct address_space *mapping;
2787 mapping = vma->vm_file->f_mapping;
2788 idx = vma_hugecache_offset(h, vma, address);
2790 page = find_get_page(mapping, idx);
2793 return page != NULL;
2796 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2797 struct address_space *mapping, pgoff_t idx,
2798 unsigned long address, pte_t *ptep, unsigned int flags)
2800 struct hstate *h = hstate_vma(vma);
2801 int ret = VM_FAULT_SIGBUS;
2809 * Currently, we are forced to kill the process in the event the
2810 * original mapper has unmapped pages from the child due to a failed
2811 * COW. Warn that such a situation has occurred as it may not be obvious
2813 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2814 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2820 * Use page lock to guard against racing truncation
2821 * before we get page_table_lock.
2824 page = find_lock_page(mapping, idx);
2826 size = i_size_read(mapping->host) >> huge_page_shift(h);
2829 page = alloc_huge_page(vma, address, 0);
2831 ret = PTR_ERR(page);
2835 ret = VM_FAULT_SIGBUS;
2838 clear_huge_page(page, address, pages_per_huge_page(h));
2839 __SetPageUptodate(page);
2841 if (vma->vm_flags & VM_MAYSHARE) {
2843 struct inode *inode = mapping->host;
2845 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2852 ClearPagePrivate(page);
2854 spin_lock(&inode->i_lock);
2855 inode->i_blocks += blocks_per_huge_page(h);
2856 spin_unlock(&inode->i_lock);
2859 if (unlikely(anon_vma_prepare(vma))) {
2861 goto backout_unlocked;
2867 * If memory error occurs between mmap() and fault, some process
2868 * don't have hwpoisoned swap entry for errored virtual address.
2869 * So we need to block hugepage fault by PG_hwpoison bit check.
2871 if (unlikely(PageHWPoison(page))) {
2872 ret = VM_FAULT_HWPOISON |
2873 VM_FAULT_SET_HINDEX(hstate_index(h));
2874 goto backout_unlocked;
2879 * If we are going to COW a private mapping later, we examine the
2880 * pending reservations for this page now. This will ensure that
2881 * any allocations necessary to record that reservation occur outside
2884 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2885 if (vma_needs_reservation(h, vma, address) < 0) {
2887 goto backout_unlocked;
2890 ptl = huge_pte_lockptr(h, mm, ptep);
2892 size = i_size_read(mapping->host) >> huge_page_shift(h);
2897 if (!huge_pte_none(huge_ptep_get(ptep)))
2901 ClearPagePrivate(page);
2902 hugepage_add_new_anon_rmap(page, vma, address);
2904 page_dup_rmap(page);
2905 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2906 && (vma->vm_flags & VM_SHARED)));
2907 set_huge_pte_at(mm, address, ptep, new_pte);
2909 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2910 /* Optimization, do the COW without a second fault */
2911 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
2928 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2929 struct vm_area_struct *vma,
2930 struct address_space *mapping,
2931 pgoff_t idx, unsigned long address)
2933 unsigned long key[2];
2936 if (vma->vm_flags & VM_SHARED) {
2937 key[0] = (unsigned long) mapping;
2940 key[0] = (unsigned long) mm;
2941 key[1] = address >> huge_page_shift(h);
2944 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
2946 return hash & (num_fault_mutexes - 1);
2950 * For uniprocesor systems we always use a single mutex, so just
2951 * return 0 and avoid the hashing overhead.
2953 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2954 struct vm_area_struct *vma,
2955 struct address_space *mapping,
2956 pgoff_t idx, unsigned long address)
2962 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2963 unsigned long address, unsigned int flags)
2970 struct page *page = NULL;
2971 struct page *pagecache_page = NULL;
2972 struct hstate *h = hstate_vma(vma);
2973 struct address_space *mapping;
2975 address &= huge_page_mask(h);
2977 ptep = huge_pte_offset(mm, address);
2979 entry = huge_ptep_get(ptep);
2980 if (unlikely(is_hugetlb_entry_migration(entry))) {
2981 migration_entry_wait_huge(vma, mm, ptep);
2983 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2984 return VM_FAULT_HWPOISON_LARGE |
2985 VM_FAULT_SET_HINDEX(hstate_index(h));
2988 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2990 return VM_FAULT_OOM;
2992 mapping = vma->vm_file->f_mapping;
2993 idx = vma_hugecache_offset(h, vma, address);
2996 * Serialize hugepage allocation and instantiation, so that we don't
2997 * get spurious allocation failures if two CPUs race to instantiate
2998 * the same page in the page cache.
3000 hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
3001 mutex_lock(&htlb_fault_mutex_table[hash]);
3003 entry = huge_ptep_get(ptep);
3004 if (huge_pte_none(entry)) {
3005 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3012 * If we are going to COW the mapping later, we examine the pending
3013 * reservations for this page now. This will ensure that any
3014 * allocations necessary to record that reservation occur outside the
3015 * spinlock. For private mappings, we also lookup the pagecache
3016 * page now as it is used to determine if a reservation has been
3019 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3020 if (vma_needs_reservation(h, vma, address) < 0) {
3025 if (!(vma->vm_flags & VM_MAYSHARE))
3026 pagecache_page = hugetlbfs_pagecache_page(h,
3031 * hugetlb_cow() requires page locks of pte_page(entry) and
3032 * pagecache_page, so here we need take the former one
3033 * when page != pagecache_page or !pagecache_page.
3034 * Note that locking order is always pagecache_page -> page,
3035 * so no worry about deadlock.
3037 page = pte_page(entry);
3039 if (page != pagecache_page)
3042 ptl = huge_pte_lockptr(h, mm, ptep);
3044 /* Check for a racing update before calling hugetlb_cow */
3045 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3049 if (flags & FAULT_FLAG_WRITE) {
3050 if (!huge_pte_write(entry)) {
3051 ret = hugetlb_cow(mm, vma, address, ptep, entry,
3052 pagecache_page, ptl);
3055 entry = huge_pte_mkdirty(entry);
3057 entry = pte_mkyoung(entry);
3058 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3059 flags & FAULT_FLAG_WRITE))
3060 update_mmu_cache(vma, address, ptep);
3065 if (pagecache_page) {
3066 unlock_page(pagecache_page);
3067 put_page(pagecache_page);
3069 if (page != pagecache_page)
3074 mutex_unlock(&htlb_fault_mutex_table[hash]);
3078 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3079 struct page **pages, struct vm_area_struct **vmas,
3080 unsigned long *position, unsigned long *nr_pages,
3081 long i, unsigned int flags)
3083 unsigned long pfn_offset;
3084 unsigned long vaddr = *position;
3085 unsigned long remainder = *nr_pages;
3086 struct hstate *h = hstate_vma(vma);
3088 while (vaddr < vma->vm_end && remainder) {
3090 spinlock_t *ptl = NULL;
3095 * Some archs (sparc64, sh*) have multiple pte_ts to
3096 * each hugepage. We have to make sure we get the
3097 * first, for the page indexing below to work.
3099 * Note that page table lock is not held when pte is null.
3101 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3103 ptl = huge_pte_lock(h, mm, pte);
3104 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3107 * When coredumping, it suits get_dump_page if we just return
3108 * an error where there's an empty slot with no huge pagecache
3109 * to back it. This way, we avoid allocating a hugepage, and
3110 * the sparse dumpfile avoids allocating disk blocks, but its
3111 * huge holes still show up with zeroes where they need to be.
3113 if (absent && (flags & FOLL_DUMP) &&
3114 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3122 * We need call hugetlb_fault for both hugepages under migration
3123 * (in which case hugetlb_fault waits for the migration,) and
3124 * hwpoisoned hugepages (in which case we need to prevent the
3125 * caller from accessing to them.) In order to do this, we use
3126 * here is_swap_pte instead of is_hugetlb_entry_migration and
3127 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3128 * both cases, and because we can't follow correct pages
3129 * directly from any kind of swap entries.
3131 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3132 ((flags & FOLL_WRITE) &&
3133 !huge_pte_write(huge_ptep_get(pte)))) {
3138 ret = hugetlb_fault(mm, vma, vaddr,
3139 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3140 if (!(ret & VM_FAULT_ERROR))
3147 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3148 page = pte_page(huge_ptep_get(pte));
3151 pages[i] = mem_map_offset(page, pfn_offset);
3152 get_page_foll(pages[i]);
3162 if (vaddr < vma->vm_end && remainder &&
3163 pfn_offset < pages_per_huge_page(h)) {
3165 * We use pfn_offset to avoid touching the pageframes
3166 * of this compound page.
3172 *nr_pages = remainder;
3175 return i ? i : -EFAULT;
3178 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3179 unsigned long address, unsigned long end, pgprot_t newprot)
3181 struct mm_struct *mm = vma->vm_mm;
3182 unsigned long start = address;
3185 struct hstate *h = hstate_vma(vma);
3186 unsigned long pages = 0;
3188 BUG_ON(address >= end);
3189 flush_cache_range(vma, address, end);
3191 mmu_notifier_invalidate_range_start(mm, start, end);
3192 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3193 for (; address < end; address += huge_page_size(h)) {
3195 ptep = huge_pte_offset(mm, address);
3198 ptl = huge_pte_lock(h, mm, ptep);
3199 if (huge_pmd_unshare(mm, &address, ptep)) {
3204 if (!huge_pte_none(huge_ptep_get(ptep))) {
3205 pte = huge_ptep_get_and_clear(mm, address, ptep);
3206 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3207 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3208 set_huge_pte_at(mm, address, ptep, pte);
3214 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3215 * may have cleared our pud entry and done put_page on the page table:
3216 * once we release i_mmap_mutex, another task can do the final put_page
3217 * and that page table be reused and filled with junk.
3219 flush_tlb_range(vma, start, end);
3220 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3221 mmu_notifier_invalidate_range_end(mm, start, end);
3223 return pages << h->order;
3226 int hugetlb_reserve_pages(struct inode *inode,
3228 struct vm_area_struct *vma,
3229 vm_flags_t vm_flags)
3232 struct hstate *h = hstate_inode(inode);
3233 struct hugepage_subpool *spool = subpool_inode(inode);
3234 struct resv_map *resv_map;
3237 * Only apply hugepage reservation if asked. At fault time, an
3238 * attempt will be made for VM_NORESERVE to allocate a page
3239 * without using reserves
3241 if (vm_flags & VM_NORESERVE)
3245 * Shared mappings base their reservation on the number of pages that
3246 * are already allocated on behalf of the file. Private mappings need
3247 * to reserve the full area even if read-only as mprotect() may be
3248 * called to make the mapping read-write. Assume !vma is a shm mapping
3250 if (!vma || vma->vm_flags & VM_MAYSHARE) {
3251 resv_map = inode_resv_map(inode);
3253 chg = region_chg(resv_map, from, to);
3256 resv_map = resv_map_alloc();
3262 set_vma_resv_map(vma, resv_map);
3263 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3271 /* There must be enough pages in the subpool for the mapping */
3272 if (hugepage_subpool_get_pages(spool, chg)) {
3278 * Check enough hugepages are available for the reservation.
3279 * Hand the pages back to the subpool if there are not
3281 ret = hugetlb_acct_memory(h, chg);
3283 hugepage_subpool_put_pages(spool, chg);
3288 * Account for the reservations made. Shared mappings record regions
3289 * that have reservations as they are shared by multiple VMAs.
3290 * When the last VMA disappears, the region map says how much
3291 * the reservation was and the page cache tells how much of
3292 * the reservation was consumed. Private mappings are per-VMA and
3293 * only the consumed reservations are tracked. When the VMA
3294 * disappears, the original reservation is the VMA size and the
3295 * consumed reservations are stored in the map. Hence, nothing
3296 * else has to be done for private mappings here
3298 if (!vma || vma->vm_flags & VM_MAYSHARE)
3299 region_add(resv_map, from, to);
3302 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3303 kref_put(&resv_map->refs, resv_map_release);
3307 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3309 struct hstate *h = hstate_inode(inode);
3310 struct resv_map *resv_map = inode_resv_map(inode);
3312 struct hugepage_subpool *spool = subpool_inode(inode);
3315 chg = region_truncate(resv_map, offset);
3316 spin_lock(&inode->i_lock);
3317 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3318 spin_unlock(&inode->i_lock);
3320 hugepage_subpool_put_pages(spool, (chg - freed));
3321 hugetlb_acct_memory(h, -(chg - freed));
3324 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3325 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3326 struct vm_area_struct *vma,
3327 unsigned long addr, pgoff_t idx)
3329 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3331 unsigned long sbase = saddr & PUD_MASK;
3332 unsigned long s_end = sbase + PUD_SIZE;
3334 /* Allow segments to share if only one is marked locked */
3335 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3336 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3339 * match the virtual addresses, permission and the alignment of the
3342 if (pmd_index(addr) != pmd_index(saddr) ||
3343 vm_flags != svm_flags ||
3344 sbase < svma->vm_start || svma->vm_end < s_end)
3350 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3352 unsigned long base = addr & PUD_MASK;
3353 unsigned long end = base + PUD_SIZE;
3356 * check on proper vm_flags and page table alignment
3358 if (vma->vm_flags & VM_MAYSHARE &&
3359 vma->vm_start <= base && end <= vma->vm_end)
3365 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3366 * and returns the corresponding pte. While this is not necessary for the
3367 * !shared pmd case because we can allocate the pmd later as well, it makes the
3368 * code much cleaner. pmd allocation is essential for the shared case because
3369 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3370 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3371 * bad pmd for sharing.
3373 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3375 struct vm_area_struct *vma = find_vma(mm, addr);
3376 struct address_space *mapping = vma->vm_file->f_mapping;
3377 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3379 struct vm_area_struct *svma;
3380 unsigned long saddr;
3385 if (!vma_shareable(vma, addr))
3386 return (pte_t *)pmd_alloc(mm, pud, addr);
3388 mutex_lock(&mapping->i_mmap_mutex);
3389 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3393 saddr = page_table_shareable(svma, vma, addr, idx);
3395 spte = huge_pte_offset(svma->vm_mm, saddr);
3397 get_page(virt_to_page(spte));
3406 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3409 pud_populate(mm, pud,
3410 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3412 put_page(virt_to_page(spte));
3415 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3416 mutex_unlock(&mapping->i_mmap_mutex);
3421 * unmap huge page backed by shared pte.
3423 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3424 * indicated by page_count > 1, unmap is achieved by clearing pud and
3425 * decrementing the ref count. If count == 1, the pte page is not shared.
3427 * called with page table lock held.
3429 * returns: 1 successfully unmapped a shared pte page
3430 * 0 the underlying pte page is not shared, or it is the last user
3432 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3434 pgd_t *pgd = pgd_offset(mm, *addr);
3435 pud_t *pud = pud_offset(pgd, *addr);
3437 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3438 if (page_count(virt_to_page(ptep)) == 1)
3442 put_page(virt_to_page(ptep));
3443 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3446 #define want_pmd_share() (1)
3447 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3448 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3452 #define want_pmd_share() (0)
3453 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3455 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3456 pte_t *huge_pte_alloc(struct mm_struct *mm,
3457 unsigned long addr, unsigned long sz)
3463 pgd = pgd_offset(mm, addr);
3464 pud = pud_alloc(mm, pgd, addr);
3466 if (sz == PUD_SIZE) {
3469 BUG_ON(sz != PMD_SIZE);
3470 if (want_pmd_share() && pud_none(*pud))
3471 pte = huge_pmd_share(mm, addr, pud);
3473 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3476 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3481 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3487 pgd = pgd_offset(mm, addr);
3488 if (pgd_present(*pgd)) {
3489 pud = pud_offset(pgd, addr);
3490 if (pud_present(*pud)) {
3492 return (pte_t *)pud;
3493 pmd = pmd_offset(pud, addr);
3496 return (pte_t *) pmd;
3500 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3501 pmd_t *pmd, int write)
3505 page = pte_page(*(pte_t *)pmd);
3507 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3512 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3513 pud_t *pud, int write)
3517 page = pte_page(*(pte_t *)pud);
3519 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3523 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3525 /* Can be overriden by architectures */
3526 struct page * __weak
3527 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3528 pud_t *pud, int write)
3534 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3536 #ifdef CONFIG_MEMORY_FAILURE
3538 /* Should be called in hugetlb_lock */
3539 static int is_hugepage_on_freelist(struct page *hpage)
3543 struct hstate *h = page_hstate(hpage);
3544 int nid = page_to_nid(hpage);
3546 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3553 * This function is called from memory failure code.
3554 * Assume the caller holds page lock of the head page.
3556 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3558 struct hstate *h = page_hstate(hpage);
3559 int nid = page_to_nid(hpage);
3562 spin_lock(&hugetlb_lock);
3563 if (is_hugepage_on_freelist(hpage)) {
3565 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3566 * but dangling hpage->lru can trigger list-debug warnings
3567 * (this happens when we call unpoison_memory() on it),
3568 * so let it point to itself with list_del_init().
3570 list_del_init(&hpage->lru);
3571 set_page_refcounted(hpage);
3572 h->free_huge_pages--;
3573 h->free_huge_pages_node[nid]--;
3576 spin_unlock(&hugetlb_lock);
3581 bool isolate_huge_page(struct page *page, struct list_head *list)
3583 VM_BUG_ON_PAGE(!PageHead(page), page);
3584 if (!get_page_unless_zero(page))
3586 spin_lock(&hugetlb_lock);
3587 list_move_tail(&page->lru, list);
3588 spin_unlock(&hugetlb_lock);
3592 void putback_active_hugepage(struct page *page)
3594 VM_BUG_ON_PAGE(!PageHead(page), page);
3595 spin_lock(&hugetlb_lock);
3596 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3597 spin_unlock(&hugetlb_lock);
3601 bool is_hugepage_active(struct page *page)
3603 VM_BUG_ON_PAGE(!PageHuge(page), page);
3605 * This function can be called for a tail page because the caller,
3606 * scan_movable_pages, scans through a given pfn-range which typically
3607 * covers one memory block. In systems using gigantic hugepage (1GB
3608 * for x86_64,) a hugepage is larger than a memory block, and we don't
3609 * support migrating such large hugepages for now, so return false
3610 * when called for tail pages.
3615 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3616 * so we should return false for them.
3618 if (unlikely(PageHWPoison(page)))
3620 return page_count(page) > 0;