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))
1179 * Determine if the huge page at addr within the vma has an associated
1180 * reservation. Where it does not we will need to logically increase
1181 * reservation and actually increase subpool usage before an allocation
1182 * can occur. Where any new reservation would be required the
1183 * reservation change is prepared, but not committed. Once the page
1184 * has been allocated from the subpool and instantiated the change should
1185 * be committed via vma_commit_reservation. No action is required on
1188 static long vma_needs_reservation(struct hstate *h,
1189 struct vm_area_struct *vma, unsigned long addr)
1191 struct resv_map *resv;
1195 resv = vma_resv_map(vma);
1199 idx = vma_hugecache_offset(h, vma, addr);
1200 chg = region_chg(resv, idx, idx + 1);
1202 if (vma->vm_flags & VM_MAYSHARE)
1205 return chg < 0 ? chg : 0;
1207 static void vma_commit_reservation(struct hstate *h,
1208 struct vm_area_struct *vma, unsigned long addr)
1210 struct resv_map *resv;
1213 resv = vma_resv_map(vma);
1217 idx = vma_hugecache_offset(h, vma, addr);
1218 region_add(resv, idx, idx + 1);
1221 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1222 unsigned long addr, int avoid_reserve)
1224 struct hugepage_subpool *spool = subpool_vma(vma);
1225 struct hstate *h = hstate_vma(vma);
1229 struct hugetlb_cgroup *h_cg;
1231 idx = hstate_index(h);
1233 * Processes that did not create the mapping will have no
1234 * reserves and will not have accounted against subpool
1235 * limit. Check that the subpool limit can be made before
1236 * satisfying the allocation MAP_NORESERVE mappings may also
1237 * need pages and subpool limit allocated allocated if no reserve
1240 chg = vma_needs_reservation(h, vma, addr);
1242 return ERR_PTR(-ENOMEM);
1243 if (chg || avoid_reserve)
1244 if (hugepage_subpool_get_pages(spool, 1))
1245 return ERR_PTR(-ENOSPC);
1247 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1249 if (chg || avoid_reserve)
1250 hugepage_subpool_put_pages(spool, 1);
1251 return ERR_PTR(-ENOSPC);
1253 spin_lock(&hugetlb_lock);
1254 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1256 spin_unlock(&hugetlb_lock);
1257 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1259 hugetlb_cgroup_uncharge_cgroup(idx,
1260 pages_per_huge_page(h),
1262 if (chg || avoid_reserve)
1263 hugepage_subpool_put_pages(spool, 1);
1264 return ERR_PTR(-ENOSPC);
1266 spin_lock(&hugetlb_lock);
1267 list_move(&page->lru, &h->hugepage_activelist);
1270 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1271 spin_unlock(&hugetlb_lock);
1273 set_page_private(page, (unsigned long)spool);
1275 vma_commit_reservation(h, vma, addr);
1280 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1281 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1282 * where no ERR_VALUE is expected to be returned.
1284 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1285 unsigned long addr, int avoid_reserve)
1287 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1293 int __weak alloc_bootmem_huge_page(struct hstate *h)
1295 struct huge_bootmem_page *m;
1298 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1301 addr = memblock_virt_alloc_try_nid_nopanic(
1302 huge_page_size(h), huge_page_size(h),
1303 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1306 * Use the beginning of the huge page to store the
1307 * huge_bootmem_page struct (until gather_bootmem
1308 * puts them into the mem_map).
1317 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1318 /* Put them into a private list first because mem_map is not up yet */
1319 list_add(&m->list, &huge_boot_pages);
1324 static void __init prep_compound_huge_page(struct page *page, int order)
1326 if (unlikely(order > (MAX_ORDER - 1)))
1327 prep_compound_gigantic_page(page, order);
1329 prep_compound_page(page, order);
1332 /* Put bootmem huge pages into the standard lists after mem_map is up */
1333 static void __init gather_bootmem_prealloc(void)
1335 struct huge_bootmem_page *m;
1337 list_for_each_entry(m, &huge_boot_pages, list) {
1338 struct hstate *h = m->hstate;
1341 #ifdef CONFIG_HIGHMEM
1342 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1343 memblock_free_late(__pa(m),
1344 sizeof(struct huge_bootmem_page));
1346 page = virt_to_page(m);
1348 WARN_ON(page_count(page) != 1);
1349 prep_compound_huge_page(page, h->order);
1350 WARN_ON(PageReserved(page));
1351 prep_new_huge_page(h, page, page_to_nid(page));
1353 * If we had gigantic hugepages allocated at boot time, we need
1354 * to restore the 'stolen' pages to totalram_pages in order to
1355 * fix confusing memory reports from free(1) and another
1356 * side-effects, like CommitLimit going negative.
1358 if (h->order > (MAX_ORDER - 1))
1359 adjust_managed_page_count(page, 1 << h->order);
1363 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1367 for (i = 0; i < h->max_huge_pages; ++i) {
1368 if (h->order >= MAX_ORDER) {
1369 if (!alloc_bootmem_huge_page(h))
1371 } else if (!alloc_fresh_huge_page(h,
1372 &node_states[N_MEMORY]))
1375 h->max_huge_pages = i;
1378 static void __init hugetlb_init_hstates(void)
1382 for_each_hstate(h) {
1383 /* oversize hugepages were init'ed in early boot */
1384 if (h->order < MAX_ORDER)
1385 hugetlb_hstate_alloc_pages(h);
1389 static char * __init memfmt(char *buf, unsigned long n)
1391 if (n >= (1UL << 30))
1392 sprintf(buf, "%lu GB", n >> 30);
1393 else if (n >= (1UL << 20))
1394 sprintf(buf, "%lu MB", n >> 20);
1396 sprintf(buf, "%lu KB", n >> 10);
1400 static void __init report_hugepages(void)
1404 for_each_hstate(h) {
1406 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1407 memfmt(buf, huge_page_size(h)),
1408 h->free_huge_pages);
1412 #ifdef CONFIG_HIGHMEM
1413 static void try_to_free_low(struct hstate *h, unsigned long count,
1414 nodemask_t *nodes_allowed)
1418 if (h->order >= MAX_ORDER)
1421 for_each_node_mask(i, *nodes_allowed) {
1422 struct page *page, *next;
1423 struct list_head *freel = &h->hugepage_freelists[i];
1424 list_for_each_entry_safe(page, next, freel, lru) {
1425 if (count >= h->nr_huge_pages)
1427 if (PageHighMem(page))
1429 list_del(&page->lru);
1430 update_and_free_page(h, page);
1431 h->free_huge_pages--;
1432 h->free_huge_pages_node[page_to_nid(page)]--;
1437 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1438 nodemask_t *nodes_allowed)
1444 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1445 * balanced by operating on them in a round-robin fashion.
1446 * Returns 1 if an adjustment was made.
1448 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1453 VM_BUG_ON(delta != -1 && delta != 1);
1456 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1457 if (h->surplus_huge_pages_node[node])
1461 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1462 if (h->surplus_huge_pages_node[node] <
1463 h->nr_huge_pages_node[node])
1470 h->surplus_huge_pages += delta;
1471 h->surplus_huge_pages_node[node] += delta;
1475 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1476 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1477 nodemask_t *nodes_allowed)
1479 unsigned long min_count, ret;
1481 if (h->order >= MAX_ORDER)
1482 return h->max_huge_pages;
1485 * Increase the pool size
1486 * First take pages out of surplus state. Then make up the
1487 * remaining difference by allocating fresh huge pages.
1489 * We might race with alloc_buddy_huge_page() here and be unable
1490 * to convert a surplus huge page to a normal huge page. That is
1491 * not critical, though, it just means the overall size of the
1492 * pool might be one hugepage larger than it needs to be, but
1493 * within all the constraints specified by the sysctls.
1495 spin_lock(&hugetlb_lock);
1496 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1497 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1501 while (count > persistent_huge_pages(h)) {
1503 * If this allocation races such that we no longer need the
1504 * page, free_huge_page will handle it by freeing the page
1505 * and reducing the surplus.
1507 spin_unlock(&hugetlb_lock);
1508 ret = alloc_fresh_huge_page(h, nodes_allowed);
1509 spin_lock(&hugetlb_lock);
1513 /* Bail for signals. Probably ctrl-c from user */
1514 if (signal_pending(current))
1519 * Decrease the pool size
1520 * First return free pages to the buddy allocator (being careful
1521 * to keep enough around to satisfy reservations). Then place
1522 * pages into surplus state as needed so the pool will shrink
1523 * to the desired size as pages become free.
1525 * By placing pages into the surplus state independent of the
1526 * overcommit value, we are allowing the surplus pool size to
1527 * exceed overcommit. There are few sane options here. Since
1528 * alloc_buddy_huge_page() is checking the global counter,
1529 * though, we'll note that we're not allowed to exceed surplus
1530 * and won't grow the pool anywhere else. Not until one of the
1531 * sysctls are changed, or the surplus pages go out of use.
1533 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1534 min_count = max(count, min_count);
1535 try_to_free_low(h, min_count, nodes_allowed);
1536 while (min_count < persistent_huge_pages(h)) {
1537 if (!free_pool_huge_page(h, nodes_allowed, 0))
1539 cond_resched_lock(&hugetlb_lock);
1541 while (count < persistent_huge_pages(h)) {
1542 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1546 ret = persistent_huge_pages(h);
1547 spin_unlock(&hugetlb_lock);
1551 #define HSTATE_ATTR_RO(_name) \
1552 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1554 #define HSTATE_ATTR(_name) \
1555 static struct kobj_attribute _name##_attr = \
1556 __ATTR(_name, 0644, _name##_show, _name##_store)
1558 static struct kobject *hugepages_kobj;
1559 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1561 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1563 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1567 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1568 if (hstate_kobjs[i] == kobj) {
1570 *nidp = NUMA_NO_NODE;
1574 return kobj_to_node_hstate(kobj, nidp);
1577 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1578 struct kobj_attribute *attr, char *buf)
1581 unsigned long nr_huge_pages;
1584 h = kobj_to_hstate(kobj, &nid);
1585 if (nid == NUMA_NO_NODE)
1586 nr_huge_pages = h->nr_huge_pages;
1588 nr_huge_pages = h->nr_huge_pages_node[nid];
1590 return sprintf(buf, "%lu\n", nr_huge_pages);
1593 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1594 struct kobject *kobj, struct kobj_attribute *attr,
1595 const char *buf, size_t len)
1599 unsigned long count;
1601 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1603 err = kstrtoul(buf, 10, &count);
1607 h = kobj_to_hstate(kobj, &nid);
1608 if (h->order >= MAX_ORDER) {
1613 if (nid == NUMA_NO_NODE) {
1615 * global hstate attribute
1617 if (!(obey_mempolicy &&
1618 init_nodemask_of_mempolicy(nodes_allowed))) {
1619 NODEMASK_FREE(nodes_allowed);
1620 nodes_allowed = &node_states[N_MEMORY];
1622 } else if (nodes_allowed) {
1624 * per node hstate attribute: adjust count to global,
1625 * but restrict alloc/free to the specified node.
1627 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1628 init_nodemask_of_node(nodes_allowed, nid);
1630 nodes_allowed = &node_states[N_MEMORY];
1632 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1634 if (nodes_allowed != &node_states[N_MEMORY])
1635 NODEMASK_FREE(nodes_allowed);
1639 NODEMASK_FREE(nodes_allowed);
1643 static ssize_t nr_hugepages_show(struct kobject *kobj,
1644 struct kobj_attribute *attr, char *buf)
1646 return nr_hugepages_show_common(kobj, attr, buf);
1649 static ssize_t nr_hugepages_store(struct kobject *kobj,
1650 struct kobj_attribute *attr, const char *buf, size_t len)
1652 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1654 HSTATE_ATTR(nr_hugepages);
1659 * hstate attribute for optionally mempolicy-based constraint on persistent
1660 * huge page alloc/free.
1662 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1663 struct kobj_attribute *attr, char *buf)
1665 return nr_hugepages_show_common(kobj, attr, buf);
1668 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1669 struct kobj_attribute *attr, const char *buf, size_t len)
1671 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1673 HSTATE_ATTR(nr_hugepages_mempolicy);
1677 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1678 struct kobj_attribute *attr, char *buf)
1680 struct hstate *h = kobj_to_hstate(kobj, NULL);
1681 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1684 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1685 struct kobj_attribute *attr, const char *buf, size_t count)
1688 unsigned long input;
1689 struct hstate *h = kobj_to_hstate(kobj, NULL);
1691 if (h->order >= MAX_ORDER)
1694 err = kstrtoul(buf, 10, &input);
1698 spin_lock(&hugetlb_lock);
1699 h->nr_overcommit_huge_pages = input;
1700 spin_unlock(&hugetlb_lock);
1704 HSTATE_ATTR(nr_overcommit_hugepages);
1706 static ssize_t free_hugepages_show(struct kobject *kobj,
1707 struct kobj_attribute *attr, char *buf)
1710 unsigned long free_huge_pages;
1713 h = kobj_to_hstate(kobj, &nid);
1714 if (nid == NUMA_NO_NODE)
1715 free_huge_pages = h->free_huge_pages;
1717 free_huge_pages = h->free_huge_pages_node[nid];
1719 return sprintf(buf, "%lu\n", free_huge_pages);
1721 HSTATE_ATTR_RO(free_hugepages);
1723 static ssize_t resv_hugepages_show(struct kobject *kobj,
1724 struct kobj_attribute *attr, char *buf)
1726 struct hstate *h = kobj_to_hstate(kobj, NULL);
1727 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1729 HSTATE_ATTR_RO(resv_hugepages);
1731 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1732 struct kobj_attribute *attr, char *buf)
1735 unsigned long surplus_huge_pages;
1738 h = kobj_to_hstate(kobj, &nid);
1739 if (nid == NUMA_NO_NODE)
1740 surplus_huge_pages = h->surplus_huge_pages;
1742 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1744 return sprintf(buf, "%lu\n", surplus_huge_pages);
1746 HSTATE_ATTR_RO(surplus_hugepages);
1748 static struct attribute *hstate_attrs[] = {
1749 &nr_hugepages_attr.attr,
1750 &nr_overcommit_hugepages_attr.attr,
1751 &free_hugepages_attr.attr,
1752 &resv_hugepages_attr.attr,
1753 &surplus_hugepages_attr.attr,
1755 &nr_hugepages_mempolicy_attr.attr,
1760 static struct attribute_group hstate_attr_group = {
1761 .attrs = hstate_attrs,
1764 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1765 struct kobject **hstate_kobjs,
1766 struct attribute_group *hstate_attr_group)
1769 int hi = hstate_index(h);
1771 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1772 if (!hstate_kobjs[hi])
1775 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1777 kobject_put(hstate_kobjs[hi]);
1782 static void __init hugetlb_sysfs_init(void)
1787 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1788 if (!hugepages_kobj)
1791 for_each_hstate(h) {
1792 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1793 hstate_kobjs, &hstate_attr_group);
1795 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1802 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1803 * with node devices in node_devices[] using a parallel array. The array
1804 * index of a node device or _hstate == node id.
1805 * This is here to avoid any static dependency of the node device driver, in
1806 * the base kernel, on the hugetlb module.
1808 struct node_hstate {
1809 struct kobject *hugepages_kobj;
1810 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1812 struct node_hstate node_hstates[MAX_NUMNODES];
1815 * A subset of global hstate attributes for node devices
1817 static struct attribute *per_node_hstate_attrs[] = {
1818 &nr_hugepages_attr.attr,
1819 &free_hugepages_attr.attr,
1820 &surplus_hugepages_attr.attr,
1824 static struct attribute_group per_node_hstate_attr_group = {
1825 .attrs = per_node_hstate_attrs,
1829 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1830 * Returns node id via non-NULL nidp.
1832 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1836 for (nid = 0; nid < nr_node_ids; nid++) {
1837 struct node_hstate *nhs = &node_hstates[nid];
1839 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1840 if (nhs->hstate_kobjs[i] == kobj) {
1852 * Unregister hstate attributes from a single node device.
1853 * No-op if no hstate attributes attached.
1855 static void hugetlb_unregister_node(struct node *node)
1858 struct node_hstate *nhs = &node_hstates[node->dev.id];
1860 if (!nhs->hugepages_kobj)
1861 return; /* no hstate attributes */
1863 for_each_hstate(h) {
1864 int idx = hstate_index(h);
1865 if (nhs->hstate_kobjs[idx]) {
1866 kobject_put(nhs->hstate_kobjs[idx]);
1867 nhs->hstate_kobjs[idx] = NULL;
1871 kobject_put(nhs->hugepages_kobj);
1872 nhs->hugepages_kobj = NULL;
1876 * hugetlb module exit: unregister hstate attributes from node devices
1879 static void hugetlb_unregister_all_nodes(void)
1884 * disable node device registrations.
1886 register_hugetlbfs_with_node(NULL, NULL);
1889 * remove hstate attributes from any nodes that have them.
1891 for (nid = 0; nid < nr_node_ids; nid++)
1892 hugetlb_unregister_node(node_devices[nid]);
1896 * Register hstate attributes for a single node device.
1897 * No-op if attributes already registered.
1899 static void hugetlb_register_node(struct node *node)
1902 struct node_hstate *nhs = &node_hstates[node->dev.id];
1905 if (nhs->hugepages_kobj)
1906 return; /* already allocated */
1908 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1910 if (!nhs->hugepages_kobj)
1913 for_each_hstate(h) {
1914 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1916 &per_node_hstate_attr_group);
1918 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1919 h->name, node->dev.id);
1920 hugetlb_unregister_node(node);
1927 * hugetlb init time: register hstate attributes for all registered node
1928 * devices of nodes that have memory. All on-line nodes should have
1929 * registered their associated device by this time.
1931 static void hugetlb_register_all_nodes(void)
1935 for_each_node_state(nid, N_MEMORY) {
1936 struct node *node = node_devices[nid];
1937 if (node->dev.id == nid)
1938 hugetlb_register_node(node);
1942 * Let the node device driver know we're here so it can
1943 * [un]register hstate attributes on node hotplug.
1945 register_hugetlbfs_with_node(hugetlb_register_node,
1946 hugetlb_unregister_node);
1948 #else /* !CONFIG_NUMA */
1950 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1958 static void hugetlb_unregister_all_nodes(void) { }
1960 static void hugetlb_register_all_nodes(void) { }
1964 static void __exit hugetlb_exit(void)
1968 hugetlb_unregister_all_nodes();
1970 for_each_hstate(h) {
1971 kobject_put(hstate_kobjs[hstate_index(h)]);
1974 kobject_put(hugepages_kobj);
1975 kfree(htlb_fault_mutex_table);
1977 module_exit(hugetlb_exit);
1979 static int __init hugetlb_init(void)
1983 /* Some platform decide whether they support huge pages at boot
1984 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1985 * there is no such support
1987 if (HPAGE_SHIFT == 0)
1990 if (!size_to_hstate(default_hstate_size)) {
1991 default_hstate_size = HPAGE_SIZE;
1992 if (!size_to_hstate(default_hstate_size))
1993 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1995 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1996 if (default_hstate_max_huge_pages)
1997 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1999 hugetlb_init_hstates();
2000 gather_bootmem_prealloc();
2003 hugetlb_sysfs_init();
2004 hugetlb_register_all_nodes();
2005 hugetlb_cgroup_file_init();
2008 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2010 num_fault_mutexes = 1;
2012 htlb_fault_mutex_table =
2013 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2014 BUG_ON(!htlb_fault_mutex_table);
2016 for (i = 0; i < num_fault_mutexes; i++)
2017 mutex_init(&htlb_fault_mutex_table[i]);
2020 module_init(hugetlb_init);
2022 /* Should be called on processing a hugepagesz=... option */
2023 void __init hugetlb_add_hstate(unsigned order)
2028 if (size_to_hstate(PAGE_SIZE << order)) {
2029 pr_warning("hugepagesz= specified twice, ignoring\n");
2032 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2034 h = &hstates[hugetlb_max_hstate++];
2036 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2037 h->nr_huge_pages = 0;
2038 h->free_huge_pages = 0;
2039 for (i = 0; i < MAX_NUMNODES; ++i)
2040 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2041 INIT_LIST_HEAD(&h->hugepage_activelist);
2042 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2043 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2044 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2045 huge_page_size(h)/1024);
2050 static int __init hugetlb_nrpages_setup(char *s)
2053 static unsigned long *last_mhp;
2056 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2057 * so this hugepages= parameter goes to the "default hstate".
2059 if (!hugetlb_max_hstate)
2060 mhp = &default_hstate_max_huge_pages;
2062 mhp = &parsed_hstate->max_huge_pages;
2064 if (mhp == last_mhp) {
2065 pr_warning("hugepages= specified twice without "
2066 "interleaving hugepagesz=, ignoring\n");
2070 if (sscanf(s, "%lu", mhp) <= 0)
2074 * Global state is always initialized later in hugetlb_init.
2075 * But we need to allocate >= MAX_ORDER hstates here early to still
2076 * use the bootmem allocator.
2078 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2079 hugetlb_hstate_alloc_pages(parsed_hstate);
2085 __setup("hugepages=", hugetlb_nrpages_setup);
2087 static int __init hugetlb_default_setup(char *s)
2089 default_hstate_size = memparse(s, &s);
2092 __setup("default_hugepagesz=", hugetlb_default_setup);
2094 static unsigned int cpuset_mems_nr(unsigned int *array)
2097 unsigned int nr = 0;
2099 for_each_node_mask(node, cpuset_current_mems_allowed)
2105 #ifdef CONFIG_SYSCTL
2106 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2107 struct ctl_table *table, int write,
2108 void __user *buffer, size_t *length, loff_t *ppos)
2110 struct hstate *h = &default_hstate;
2114 tmp = h->max_huge_pages;
2116 if (write && h->order >= MAX_ORDER)
2120 table->maxlen = sizeof(unsigned long);
2121 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2126 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2127 GFP_KERNEL | __GFP_NORETRY);
2128 if (!(obey_mempolicy &&
2129 init_nodemask_of_mempolicy(nodes_allowed))) {
2130 NODEMASK_FREE(nodes_allowed);
2131 nodes_allowed = &node_states[N_MEMORY];
2133 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2135 if (nodes_allowed != &node_states[N_MEMORY])
2136 NODEMASK_FREE(nodes_allowed);
2142 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2143 void __user *buffer, size_t *length, loff_t *ppos)
2146 return hugetlb_sysctl_handler_common(false, table, write,
2147 buffer, length, ppos);
2151 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2152 void __user *buffer, size_t *length, loff_t *ppos)
2154 return hugetlb_sysctl_handler_common(true, table, write,
2155 buffer, length, ppos);
2157 #endif /* CONFIG_NUMA */
2159 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2160 void __user *buffer,
2161 size_t *length, loff_t *ppos)
2163 struct hstate *h = &default_hstate;
2167 tmp = h->nr_overcommit_huge_pages;
2169 if (write && h->order >= MAX_ORDER)
2173 table->maxlen = sizeof(unsigned long);
2174 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2179 spin_lock(&hugetlb_lock);
2180 h->nr_overcommit_huge_pages = tmp;
2181 spin_unlock(&hugetlb_lock);
2187 #endif /* CONFIG_SYSCTL */
2189 void hugetlb_report_meminfo(struct seq_file *m)
2191 struct hstate *h = &default_hstate;
2193 "HugePages_Total: %5lu\n"
2194 "HugePages_Free: %5lu\n"
2195 "HugePages_Rsvd: %5lu\n"
2196 "HugePages_Surp: %5lu\n"
2197 "Hugepagesize: %8lu kB\n",
2201 h->surplus_huge_pages,
2202 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2205 int hugetlb_report_node_meminfo(int nid, char *buf)
2207 struct hstate *h = &default_hstate;
2209 "Node %d HugePages_Total: %5u\n"
2210 "Node %d HugePages_Free: %5u\n"
2211 "Node %d HugePages_Surp: %5u\n",
2212 nid, h->nr_huge_pages_node[nid],
2213 nid, h->free_huge_pages_node[nid],
2214 nid, h->surplus_huge_pages_node[nid]);
2217 void hugetlb_show_meminfo(void)
2222 for_each_node_state(nid, N_MEMORY)
2224 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2226 h->nr_huge_pages_node[nid],
2227 h->free_huge_pages_node[nid],
2228 h->surplus_huge_pages_node[nid],
2229 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2232 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2233 unsigned long hugetlb_total_pages(void)
2236 unsigned long nr_total_pages = 0;
2239 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2240 return nr_total_pages;
2243 static int hugetlb_acct_memory(struct hstate *h, long delta)
2247 spin_lock(&hugetlb_lock);
2249 * When cpuset is configured, it breaks the strict hugetlb page
2250 * reservation as the accounting is done on a global variable. Such
2251 * reservation is completely rubbish in the presence of cpuset because
2252 * the reservation is not checked against page availability for the
2253 * current cpuset. Application can still potentially OOM'ed by kernel
2254 * with lack of free htlb page in cpuset that the task is in.
2255 * Attempt to enforce strict accounting with cpuset is almost
2256 * impossible (or too ugly) because cpuset is too fluid that
2257 * task or memory node can be dynamically moved between cpusets.
2259 * The change of semantics for shared hugetlb mapping with cpuset is
2260 * undesirable. However, in order to preserve some of the semantics,
2261 * we fall back to check against current free page availability as
2262 * a best attempt and hopefully to minimize the impact of changing
2263 * semantics that cpuset has.
2266 if (gather_surplus_pages(h, delta) < 0)
2269 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2270 return_unused_surplus_pages(h, delta);
2277 return_unused_surplus_pages(h, (unsigned long) -delta);
2280 spin_unlock(&hugetlb_lock);
2284 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2286 struct resv_map *resv = vma_resv_map(vma);
2289 * This new VMA should share its siblings reservation map if present.
2290 * The VMA will only ever have a valid reservation map pointer where
2291 * it is being copied for another still existing VMA. As that VMA
2292 * has a reference to the reservation map it cannot disappear until
2293 * after this open call completes. It is therefore safe to take a
2294 * new reference here without additional locking.
2296 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2297 kref_get(&resv->refs);
2300 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2302 struct hstate *h = hstate_vma(vma);
2303 struct resv_map *resv = vma_resv_map(vma);
2304 struct hugepage_subpool *spool = subpool_vma(vma);
2305 unsigned long reserve, start, end;
2307 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2310 start = vma_hugecache_offset(h, vma, vma->vm_start);
2311 end = vma_hugecache_offset(h, vma, vma->vm_end);
2313 reserve = (end - start) - region_count(resv, start, end);
2315 kref_put(&resv->refs, resv_map_release);
2318 hugetlb_acct_memory(h, -reserve);
2319 hugepage_subpool_put_pages(spool, reserve);
2324 * We cannot handle pagefaults against hugetlb pages at all. They cause
2325 * handle_mm_fault() to try to instantiate regular-sized pages in the
2326 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2329 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2335 const struct vm_operations_struct hugetlb_vm_ops = {
2336 .fault = hugetlb_vm_op_fault,
2337 .open = hugetlb_vm_op_open,
2338 .close = hugetlb_vm_op_close,
2341 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2347 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2348 vma->vm_page_prot)));
2350 entry = huge_pte_wrprotect(mk_huge_pte(page,
2351 vma->vm_page_prot));
2353 entry = pte_mkyoung(entry);
2354 entry = pte_mkhuge(entry);
2355 entry = arch_make_huge_pte(entry, vma, page, writable);
2360 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2361 unsigned long address, pte_t *ptep)
2365 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2366 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2367 update_mmu_cache(vma, address, ptep);
2371 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2372 struct vm_area_struct *vma)
2374 pte_t *src_pte, *dst_pte, entry;
2375 struct page *ptepage;
2378 struct hstate *h = hstate_vma(vma);
2379 unsigned long sz = huge_page_size(h);
2380 unsigned long mmun_start; /* For mmu_notifiers */
2381 unsigned long mmun_end; /* For mmu_notifiers */
2384 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2386 mmun_start = vma->vm_start;
2387 mmun_end = vma->vm_end;
2389 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
2391 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2392 spinlock_t *src_ptl, *dst_ptl;
2393 src_pte = huge_pte_offset(src, addr);
2396 dst_pte = huge_pte_alloc(dst, addr, sz);
2402 /* If the pagetables are shared don't copy or take references */
2403 if (dst_pte == src_pte)
2406 dst_ptl = huge_pte_lock(h, dst, dst_pte);
2407 src_ptl = huge_pte_lockptr(h, src, src_pte);
2408 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2409 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2411 huge_ptep_set_wrprotect(src, addr, src_pte);
2412 entry = huge_ptep_get(src_pte);
2413 ptepage = pte_page(entry);
2415 page_dup_rmap(ptepage);
2416 set_huge_pte_at(dst, addr, dst_pte, entry);
2418 spin_unlock(src_ptl);
2419 spin_unlock(dst_ptl);
2423 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
2428 static int is_hugetlb_entry_migration(pte_t pte)
2432 if (huge_pte_none(pte) || pte_present(pte))
2434 swp = pte_to_swp_entry(pte);
2435 if (non_swap_entry(swp) && is_migration_entry(swp))
2441 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2445 if (huge_pte_none(pte) || pte_present(pte))
2447 swp = pte_to_swp_entry(pte);
2448 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2454 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2455 unsigned long start, unsigned long end,
2456 struct page *ref_page)
2458 int force_flush = 0;
2459 struct mm_struct *mm = vma->vm_mm;
2460 unsigned long address;
2465 struct hstate *h = hstate_vma(vma);
2466 unsigned long sz = huge_page_size(h);
2467 const unsigned long mmun_start = start; /* For mmu_notifiers */
2468 const unsigned long mmun_end = end; /* For mmu_notifiers */
2470 WARN_ON(!is_vm_hugetlb_page(vma));
2471 BUG_ON(start & ~huge_page_mask(h));
2472 BUG_ON(end & ~huge_page_mask(h));
2474 tlb_start_vma(tlb, vma);
2475 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2477 for (address = start; address < end; address += sz) {
2478 ptep = huge_pte_offset(mm, address);
2482 ptl = huge_pte_lock(h, mm, ptep);
2483 if (huge_pmd_unshare(mm, &address, ptep))
2486 pte = huge_ptep_get(ptep);
2487 if (huge_pte_none(pte))
2491 * HWPoisoned hugepage is already unmapped and dropped reference
2493 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2494 huge_pte_clear(mm, address, ptep);
2498 page = pte_page(pte);
2500 * If a reference page is supplied, it is because a specific
2501 * page is being unmapped, not a range. Ensure the page we
2502 * are about to unmap is the actual page of interest.
2505 if (page != ref_page)
2509 * Mark the VMA as having unmapped its page so that
2510 * future faults in this VMA will fail rather than
2511 * looking like data was lost
2513 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2516 pte = huge_ptep_get_and_clear(mm, address, ptep);
2517 tlb_remove_tlb_entry(tlb, ptep, address);
2518 if (huge_pte_dirty(pte))
2519 set_page_dirty(page);
2521 page_remove_rmap(page);
2522 force_flush = !__tlb_remove_page(tlb, page);
2527 /* Bail out after unmapping reference page if supplied */
2536 * mmu_gather ran out of room to batch pages, we break out of
2537 * the PTE lock to avoid doing the potential expensive TLB invalidate
2538 * and page-free while holding it.
2543 if (address < end && !ref_page)
2546 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2547 tlb_end_vma(tlb, vma);
2550 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2551 struct vm_area_struct *vma, unsigned long start,
2552 unsigned long end, struct page *ref_page)
2554 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2557 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2558 * test will fail on a vma being torn down, and not grab a page table
2559 * on its way out. We're lucky that the flag has such an appropriate
2560 * name, and can in fact be safely cleared here. We could clear it
2561 * before the __unmap_hugepage_range above, but all that's necessary
2562 * is to clear it before releasing the i_mmap_mutex. This works
2563 * because in the context this is called, the VMA is about to be
2564 * destroyed and the i_mmap_mutex is held.
2566 vma->vm_flags &= ~VM_MAYSHARE;
2569 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2570 unsigned long end, struct page *ref_page)
2572 struct mm_struct *mm;
2573 struct mmu_gather tlb;
2577 tlb_gather_mmu(&tlb, mm, start, end);
2578 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2579 tlb_finish_mmu(&tlb, start, end);
2583 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2584 * mappping it owns the reserve page for. The intention is to unmap the page
2585 * from other VMAs and let the children be SIGKILLed if they are faulting the
2588 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2589 struct page *page, unsigned long address)
2591 struct hstate *h = hstate_vma(vma);
2592 struct vm_area_struct *iter_vma;
2593 struct address_space *mapping;
2597 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2598 * from page cache lookup which is in HPAGE_SIZE units.
2600 address = address & huge_page_mask(h);
2601 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2603 mapping = file_inode(vma->vm_file)->i_mapping;
2606 * Take the mapping lock for the duration of the table walk. As
2607 * this mapping should be shared between all the VMAs,
2608 * __unmap_hugepage_range() is called as the lock is already held
2610 mutex_lock(&mapping->i_mmap_mutex);
2611 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2612 /* Do not unmap the current VMA */
2613 if (iter_vma == vma)
2617 * Unmap the page from other VMAs without their own reserves.
2618 * They get marked to be SIGKILLed if they fault in these
2619 * areas. This is because a future no-page fault on this VMA
2620 * could insert a zeroed page instead of the data existing
2621 * from the time of fork. This would look like data corruption
2623 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2624 unmap_hugepage_range(iter_vma, address,
2625 address + huge_page_size(h), page);
2627 mutex_unlock(&mapping->i_mmap_mutex);
2633 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2634 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2635 * cannot race with other handlers or page migration.
2636 * Keep the pte_same checks anyway to make transition from the mutex easier.
2638 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2639 unsigned long address, pte_t *ptep, pte_t pte,
2640 struct page *pagecache_page, spinlock_t *ptl)
2642 struct hstate *h = hstate_vma(vma);
2643 struct page *old_page, *new_page;
2644 int outside_reserve = 0;
2645 unsigned long mmun_start; /* For mmu_notifiers */
2646 unsigned long mmun_end; /* For mmu_notifiers */
2648 old_page = pte_page(pte);
2651 /* If no-one else is actually using this page, avoid the copy
2652 * and just make the page writable */
2653 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2654 page_move_anon_rmap(old_page, vma, address);
2655 set_huge_ptep_writable(vma, address, ptep);
2660 * If the process that created a MAP_PRIVATE mapping is about to
2661 * perform a COW due to a shared page count, attempt to satisfy
2662 * the allocation without using the existing reserves. The pagecache
2663 * page is used to determine if the reserve at this address was
2664 * consumed or not. If reserves were used, a partial faulted mapping
2665 * at the time of fork() could consume its reserves on COW instead
2666 * of the full address range.
2668 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2669 old_page != pagecache_page)
2670 outside_reserve = 1;
2672 page_cache_get(old_page);
2674 /* Drop page table lock as buddy allocator may be called */
2676 new_page = alloc_huge_page(vma, address, outside_reserve);
2678 if (IS_ERR(new_page)) {
2679 long err = PTR_ERR(new_page);
2680 page_cache_release(old_page);
2683 * If a process owning a MAP_PRIVATE mapping fails to COW,
2684 * it is due to references held by a child and an insufficient
2685 * huge page pool. To guarantee the original mappers
2686 * reliability, unmap the page from child processes. The child
2687 * may get SIGKILLed if it later faults.
2689 if (outside_reserve) {
2690 BUG_ON(huge_pte_none(pte));
2691 if (unmap_ref_private(mm, vma, old_page, address)) {
2692 BUG_ON(huge_pte_none(pte));
2694 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2696 pte_same(huge_ptep_get(ptep), pte)))
2697 goto retry_avoidcopy;
2699 * race occurs while re-acquiring page table
2700 * lock, and our job is done.
2707 /* Caller expects lock to be held */
2710 return VM_FAULT_OOM;
2712 return VM_FAULT_SIGBUS;
2716 * When the original hugepage is shared one, it does not have
2717 * anon_vma prepared.
2719 if (unlikely(anon_vma_prepare(vma))) {
2720 page_cache_release(new_page);
2721 page_cache_release(old_page);
2722 /* Caller expects lock to be held */
2724 return VM_FAULT_OOM;
2727 copy_user_huge_page(new_page, old_page, address, vma,
2728 pages_per_huge_page(h));
2729 __SetPageUptodate(new_page);
2731 mmun_start = address & huge_page_mask(h);
2732 mmun_end = mmun_start + huge_page_size(h);
2733 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2735 * Retake the page table lock to check for racing updates
2736 * before the page tables are altered
2739 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2740 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
2741 ClearPagePrivate(new_page);
2744 huge_ptep_clear_flush(vma, address, ptep);
2745 set_huge_pte_at(mm, address, ptep,
2746 make_huge_pte(vma, new_page, 1));
2747 page_remove_rmap(old_page);
2748 hugepage_add_new_anon_rmap(new_page, vma, address);
2749 /* Make the old page be freed below */
2750 new_page = old_page;
2753 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2754 page_cache_release(new_page);
2755 page_cache_release(old_page);
2757 /* Caller expects lock to be held */
2762 /* Return the pagecache page at a given address within a VMA */
2763 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2764 struct vm_area_struct *vma, unsigned long address)
2766 struct address_space *mapping;
2769 mapping = vma->vm_file->f_mapping;
2770 idx = vma_hugecache_offset(h, vma, address);
2772 return find_lock_page(mapping, idx);
2776 * Return whether there is a pagecache page to back given address within VMA.
2777 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2779 static bool hugetlbfs_pagecache_present(struct hstate *h,
2780 struct vm_area_struct *vma, unsigned long address)
2782 struct address_space *mapping;
2786 mapping = vma->vm_file->f_mapping;
2787 idx = vma_hugecache_offset(h, vma, address);
2789 page = find_get_page(mapping, idx);
2792 return page != NULL;
2795 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2796 struct address_space *mapping, pgoff_t idx,
2797 unsigned long address, pte_t *ptep, unsigned int flags)
2799 struct hstate *h = hstate_vma(vma);
2800 int ret = VM_FAULT_SIGBUS;
2808 * Currently, we are forced to kill the process in the event the
2809 * original mapper has unmapped pages from the child due to a failed
2810 * COW. Warn that such a situation has occurred as it may not be obvious
2812 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2813 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2819 * Use page lock to guard against racing truncation
2820 * before we get page_table_lock.
2823 page = find_lock_page(mapping, idx);
2825 size = i_size_read(mapping->host) >> huge_page_shift(h);
2828 page = alloc_huge_page(vma, address, 0);
2830 ret = PTR_ERR(page);
2834 ret = VM_FAULT_SIGBUS;
2837 clear_huge_page(page, address, pages_per_huge_page(h));
2838 __SetPageUptodate(page);
2840 if (vma->vm_flags & VM_MAYSHARE) {
2842 struct inode *inode = mapping->host;
2844 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2851 ClearPagePrivate(page);
2853 spin_lock(&inode->i_lock);
2854 inode->i_blocks += blocks_per_huge_page(h);
2855 spin_unlock(&inode->i_lock);
2858 if (unlikely(anon_vma_prepare(vma))) {
2860 goto backout_unlocked;
2866 * If memory error occurs between mmap() and fault, some process
2867 * don't have hwpoisoned swap entry for errored virtual address.
2868 * So we need to block hugepage fault by PG_hwpoison bit check.
2870 if (unlikely(PageHWPoison(page))) {
2871 ret = VM_FAULT_HWPOISON |
2872 VM_FAULT_SET_HINDEX(hstate_index(h));
2873 goto backout_unlocked;
2878 * If we are going to COW a private mapping later, we examine the
2879 * pending reservations for this page now. This will ensure that
2880 * any allocations necessary to record that reservation occur outside
2883 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2884 if (vma_needs_reservation(h, vma, address) < 0) {
2886 goto backout_unlocked;
2889 ptl = huge_pte_lockptr(h, mm, ptep);
2891 size = i_size_read(mapping->host) >> huge_page_shift(h);
2896 if (!huge_pte_none(huge_ptep_get(ptep)))
2900 ClearPagePrivate(page);
2901 hugepage_add_new_anon_rmap(page, vma, address);
2903 page_dup_rmap(page);
2904 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2905 && (vma->vm_flags & VM_SHARED)));
2906 set_huge_pte_at(mm, address, ptep, new_pte);
2908 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2909 /* Optimization, do the COW without a second fault */
2910 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
2927 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2928 struct vm_area_struct *vma,
2929 struct address_space *mapping,
2930 pgoff_t idx, unsigned long address)
2932 unsigned long key[2];
2935 if (vma->vm_flags & VM_SHARED) {
2936 key[0] = (unsigned long) mapping;
2939 key[0] = (unsigned long) mm;
2940 key[1] = address >> huge_page_shift(h);
2943 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
2945 return hash & (num_fault_mutexes - 1);
2949 * For uniprocesor systems we always use a single mutex, so just
2950 * return 0 and avoid the hashing overhead.
2952 static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2953 struct vm_area_struct *vma,
2954 struct address_space *mapping,
2955 pgoff_t idx, unsigned long address)
2961 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2962 unsigned long address, unsigned int flags)
2969 struct page *page = NULL;
2970 struct page *pagecache_page = NULL;
2971 struct hstate *h = hstate_vma(vma);
2972 struct address_space *mapping;
2974 address &= huge_page_mask(h);
2976 ptep = huge_pte_offset(mm, address);
2978 entry = huge_ptep_get(ptep);
2979 if (unlikely(is_hugetlb_entry_migration(entry))) {
2980 migration_entry_wait_huge(vma, mm, ptep);
2982 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2983 return VM_FAULT_HWPOISON_LARGE |
2984 VM_FAULT_SET_HINDEX(hstate_index(h));
2987 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2989 return VM_FAULT_OOM;
2991 mapping = vma->vm_file->f_mapping;
2992 idx = vma_hugecache_offset(h, vma, address);
2995 * Serialize hugepage allocation and instantiation, so that we don't
2996 * get spurious allocation failures if two CPUs race to instantiate
2997 * the same page in the page cache.
2999 hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
3000 mutex_lock(&htlb_fault_mutex_table[hash]);
3002 entry = huge_ptep_get(ptep);
3003 if (huge_pte_none(entry)) {
3004 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3011 * If we are going to COW the mapping later, we examine the pending
3012 * reservations for this page now. This will ensure that any
3013 * allocations necessary to record that reservation occur outside the
3014 * spinlock. For private mappings, we also lookup the pagecache
3015 * page now as it is used to determine if a reservation has been
3018 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3019 if (vma_needs_reservation(h, vma, address) < 0) {
3024 if (!(vma->vm_flags & VM_MAYSHARE))
3025 pagecache_page = hugetlbfs_pagecache_page(h,
3030 * hugetlb_cow() requires page locks of pte_page(entry) and
3031 * pagecache_page, so here we need take the former one
3032 * when page != pagecache_page or !pagecache_page.
3033 * Note that locking order is always pagecache_page -> page,
3034 * so no worry about deadlock.
3036 page = pte_page(entry);
3038 if (page != pagecache_page)
3041 ptl = huge_pte_lockptr(h, mm, ptep);
3043 /* Check for a racing update before calling hugetlb_cow */
3044 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3048 if (flags & FAULT_FLAG_WRITE) {
3049 if (!huge_pte_write(entry)) {
3050 ret = hugetlb_cow(mm, vma, address, ptep, entry,
3051 pagecache_page, ptl);
3054 entry = huge_pte_mkdirty(entry);
3056 entry = pte_mkyoung(entry);
3057 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3058 flags & FAULT_FLAG_WRITE))
3059 update_mmu_cache(vma, address, ptep);
3064 if (pagecache_page) {
3065 unlock_page(pagecache_page);
3066 put_page(pagecache_page);
3068 if (page != pagecache_page)
3073 mutex_unlock(&htlb_fault_mutex_table[hash]);
3077 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3078 struct page **pages, struct vm_area_struct **vmas,
3079 unsigned long *position, unsigned long *nr_pages,
3080 long i, unsigned int flags)
3082 unsigned long pfn_offset;
3083 unsigned long vaddr = *position;
3084 unsigned long remainder = *nr_pages;
3085 struct hstate *h = hstate_vma(vma);
3087 while (vaddr < vma->vm_end && remainder) {
3089 spinlock_t *ptl = NULL;
3094 * Some archs (sparc64, sh*) have multiple pte_ts to
3095 * each hugepage. We have to make sure we get the
3096 * first, for the page indexing below to work.
3098 * Note that page table lock is not held when pte is null.
3100 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3102 ptl = huge_pte_lock(h, mm, pte);
3103 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3106 * When coredumping, it suits get_dump_page if we just return
3107 * an error where there's an empty slot with no huge pagecache
3108 * to back it. This way, we avoid allocating a hugepage, and
3109 * the sparse dumpfile avoids allocating disk blocks, but its
3110 * huge holes still show up with zeroes where they need to be.
3112 if (absent && (flags & FOLL_DUMP) &&
3113 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3121 * We need call hugetlb_fault for both hugepages under migration
3122 * (in which case hugetlb_fault waits for the migration,) and
3123 * hwpoisoned hugepages (in which case we need to prevent the
3124 * caller from accessing to them.) In order to do this, we use
3125 * here is_swap_pte instead of is_hugetlb_entry_migration and
3126 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3127 * both cases, and because we can't follow correct pages
3128 * directly from any kind of swap entries.
3130 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3131 ((flags & FOLL_WRITE) &&
3132 !huge_pte_write(huge_ptep_get(pte)))) {
3137 ret = hugetlb_fault(mm, vma, vaddr,
3138 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3139 if (!(ret & VM_FAULT_ERROR))
3146 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3147 page = pte_page(huge_ptep_get(pte));
3150 pages[i] = mem_map_offset(page, pfn_offset);
3151 get_page_foll(pages[i]);
3161 if (vaddr < vma->vm_end && remainder &&
3162 pfn_offset < pages_per_huge_page(h)) {
3164 * We use pfn_offset to avoid touching the pageframes
3165 * of this compound page.
3171 *nr_pages = remainder;
3174 return i ? i : -EFAULT;
3177 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3178 unsigned long address, unsigned long end, pgprot_t newprot)
3180 struct mm_struct *mm = vma->vm_mm;
3181 unsigned long start = address;
3184 struct hstate *h = hstate_vma(vma);
3185 unsigned long pages = 0;
3187 BUG_ON(address >= end);
3188 flush_cache_range(vma, address, end);
3190 mmu_notifier_invalidate_range_start(mm, start, end);
3191 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3192 for (; address < end; address += huge_page_size(h)) {
3194 ptep = huge_pte_offset(mm, address);
3197 ptl = huge_pte_lock(h, mm, ptep);
3198 if (huge_pmd_unshare(mm, &address, ptep)) {
3203 if (!huge_pte_none(huge_ptep_get(ptep))) {
3204 pte = huge_ptep_get_and_clear(mm, address, ptep);
3205 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3206 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3207 set_huge_pte_at(mm, address, ptep, pte);
3213 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3214 * may have cleared our pud entry and done put_page on the page table:
3215 * once we release i_mmap_mutex, another task can do the final put_page
3216 * and that page table be reused and filled with junk.
3218 flush_tlb_range(vma, start, end);
3219 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3220 mmu_notifier_invalidate_range_end(mm, start, end);
3222 return pages << h->order;
3225 int hugetlb_reserve_pages(struct inode *inode,
3227 struct vm_area_struct *vma,
3228 vm_flags_t vm_flags)
3231 struct hstate *h = hstate_inode(inode);
3232 struct hugepage_subpool *spool = subpool_inode(inode);
3233 struct resv_map *resv_map;
3236 * Only apply hugepage reservation if asked. At fault time, an
3237 * attempt will be made for VM_NORESERVE to allocate a page
3238 * without using reserves
3240 if (vm_flags & VM_NORESERVE)
3244 * Shared mappings base their reservation on the number of pages that
3245 * are already allocated on behalf of the file. Private mappings need
3246 * to reserve the full area even if read-only as mprotect() may be
3247 * called to make the mapping read-write. Assume !vma is a shm mapping
3249 if (!vma || vma->vm_flags & VM_MAYSHARE) {
3250 resv_map = inode_resv_map(inode);
3252 chg = region_chg(resv_map, from, to);
3255 resv_map = resv_map_alloc();
3261 set_vma_resv_map(vma, resv_map);
3262 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3270 /* There must be enough pages in the subpool for the mapping */
3271 if (hugepage_subpool_get_pages(spool, chg)) {
3277 * Check enough hugepages are available for the reservation.
3278 * Hand the pages back to the subpool if there are not
3280 ret = hugetlb_acct_memory(h, chg);
3282 hugepage_subpool_put_pages(spool, chg);
3287 * Account for the reservations made. Shared mappings record regions
3288 * that have reservations as they are shared by multiple VMAs.
3289 * When the last VMA disappears, the region map says how much
3290 * the reservation was and the page cache tells how much of
3291 * the reservation was consumed. Private mappings are per-VMA and
3292 * only the consumed reservations are tracked. When the VMA
3293 * disappears, the original reservation is the VMA size and the
3294 * consumed reservations are stored in the map. Hence, nothing
3295 * else has to be done for private mappings here
3297 if (!vma || vma->vm_flags & VM_MAYSHARE)
3298 region_add(resv_map, from, to);
3301 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3302 kref_put(&resv_map->refs, resv_map_release);
3306 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3308 struct hstate *h = hstate_inode(inode);
3309 struct resv_map *resv_map = inode_resv_map(inode);
3311 struct hugepage_subpool *spool = subpool_inode(inode);
3314 chg = region_truncate(resv_map, offset);
3315 spin_lock(&inode->i_lock);
3316 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3317 spin_unlock(&inode->i_lock);
3319 hugepage_subpool_put_pages(spool, (chg - freed));
3320 hugetlb_acct_memory(h, -(chg - freed));
3323 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3324 static unsigned long page_table_shareable(struct vm_area_struct *svma,
3325 struct vm_area_struct *vma,
3326 unsigned long addr, pgoff_t idx)
3328 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3330 unsigned long sbase = saddr & PUD_MASK;
3331 unsigned long s_end = sbase + PUD_SIZE;
3333 /* Allow segments to share if only one is marked locked */
3334 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3335 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3338 * match the virtual addresses, permission and the alignment of the
3341 if (pmd_index(addr) != pmd_index(saddr) ||
3342 vm_flags != svm_flags ||
3343 sbase < svma->vm_start || svma->vm_end < s_end)
3349 static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3351 unsigned long base = addr & PUD_MASK;
3352 unsigned long end = base + PUD_SIZE;
3355 * check on proper vm_flags and page table alignment
3357 if (vma->vm_flags & VM_MAYSHARE &&
3358 vma->vm_start <= base && end <= vma->vm_end)
3364 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3365 * and returns the corresponding pte. While this is not necessary for the
3366 * !shared pmd case because we can allocate the pmd later as well, it makes the
3367 * code much cleaner. pmd allocation is essential for the shared case because
3368 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3369 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3370 * bad pmd for sharing.
3372 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3374 struct vm_area_struct *vma = find_vma(mm, addr);
3375 struct address_space *mapping = vma->vm_file->f_mapping;
3376 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3378 struct vm_area_struct *svma;
3379 unsigned long saddr;
3384 if (!vma_shareable(vma, addr))
3385 return (pte_t *)pmd_alloc(mm, pud, addr);
3387 mutex_lock(&mapping->i_mmap_mutex);
3388 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3392 saddr = page_table_shareable(svma, vma, addr, idx);
3394 spte = huge_pte_offset(svma->vm_mm, saddr);
3396 get_page(virt_to_page(spte));
3405 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3408 pud_populate(mm, pud,
3409 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3411 put_page(virt_to_page(spte));
3414 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3415 mutex_unlock(&mapping->i_mmap_mutex);
3420 * unmap huge page backed by shared pte.
3422 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3423 * indicated by page_count > 1, unmap is achieved by clearing pud and
3424 * decrementing the ref count. If count == 1, the pte page is not shared.
3426 * called with page table lock held.
3428 * returns: 1 successfully unmapped a shared pte page
3429 * 0 the underlying pte page is not shared, or it is the last user
3431 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3433 pgd_t *pgd = pgd_offset(mm, *addr);
3434 pud_t *pud = pud_offset(pgd, *addr);
3436 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3437 if (page_count(virt_to_page(ptep)) == 1)
3441 put_page(virt_to_page(ptep));
3442 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3445 #define want_pmd_share() (1)
3446 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3447 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3451 #define want_pmd_share() (0)
3452 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3454 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3455 pte_t *huge_pte_alloc(struct mm_struct *mm,
3456 unsigned long addr, unsigned long sz)
3462 pgd = pgd_offset(mm, addr);
3463 pud = pud_alloc(mm, pgd, addr);
3465 if (sz == PUD_SIZE) {
3468 BUG_ON(sz != PMD_SIZE);
3469 if (want_pmd_share() && pud_none(*pud))
3470 pte = huge_pmd_share(mm, addr, pud);
3472 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3475 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3480 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3486 pgd = pgd_offset(mm, addr);
3487 if (pgd_present(*pgd)) {
3488 pud = pud_offset(pgd, addr);
3489 if (pud_present(*pud)) {
3491 return (pte_t *)pud;
3492 pmd = pmd_offset(pud, addr);
3495 return (pte_t *) pmd;
3499 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3500 pmd_t *pmd, int write)
3504 page = pte_page(*(pte_t *)pmd);
3506 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3511 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3512 pud_t *pud, int write)
3516 page = pte_page(*(pte_t *)pud);
3518 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3522 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3524 /* Can be overriden by architectures */
3525 struct page * __weak
3526 follow_huge_pud(struct mm_struct *mm, unsigned long address,
3527 pud_t *pud, int write)
3533 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3535 #ifdef CONFIG_MEMORY_FAILURE
3537 /* Should be called in hugetlb_lock */
3538 static int is_hugepage_on_freelist(struct page *hpage)
3542 struct hstate *h = page_hstate(hpage);
3543 int nid = page_to_nid(hpage);
3545 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3552 * This function is called from memory failure code.
3553 * Assume the caller holds page lock of the head page.
3555 int dequeue_hwpoisoned_huge_page(struct page *hpage)
3557 struct hstate *h = page_hstate(hpage);
3558 int nid = page_to_nid(hpage);
3561 spin_lock(&hugetlb_lock);
3562 if (is_hugepage_on_freelist(hpage)) {
3564 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3565 * but dangling hpage->lru can trigger list-debug warnings
3566 * (this happens when we call unpoison_memory() on it),
3567 * so let it point to itself with list_del_init().
3569 list_del_init(&hpage->lru);
3570 set_page_refcounted(hpage);
3571 h->free_huge_pages--;
3572 h->free_huge_pages_node[nid]--;
3575 spin_unlock(&hugetlb_lock);
3580 bool isolate_huge_page(struct page *page, struct list_head *list)
3582 VM_BUG_ON_PAGE(!PageHead(page), page);
3583 if (!get_page_unless_zero(page))
3585 spin_lock(&hugetlb_lock);
3586 list_move_tail(&page->lru, list);
3587 spin_unlock(&hugetlb_lock);
3591 void putback_active_hugepage(struct page *page)
3593 VM_BUG_ON_PAGE(!PageHead(page), page);
3594 spin_lock(&hugetlb_lock);
3595 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3596 spin_unlock(&hugetlb_lock);
3600 bool is_hugepage_active(struct page *page)
3602 VM_BUG_ON_PAGE(!PageHuge(page), page);
3604 * This function can be called for a tail page because the caller,
3605 * scan_movable_pages, scans through a given pfn-range which typically
3606 * covers one memory block. In systems using gigantic hugepage (1GB
3607 * for x86_64,) a hugepage is larger than a memory block, and we don't
3608 * support migrating such large hugepages for now, so return false
3609 * when called for tail pages.
3614 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3615 * so we should return false for them.
3617 if (unlikely(PageHWPoison(page)))
3619 return page_count(page) > 0;