2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
26 #include <asm/pgtable.h>
29 #include <linux/hugetlb.h>
30 #include <linux/node.h>
33 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
34 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
35 unsigned long hugepages_treat_as_movable;
37 static int max_hstate;
38 unsigned int default_hstate_idx;
39 struct hstate hstates[HUGE_MAX_HSTATE];
41 __initdata LIST_HEAD(huge_boot_pages);
43 /* for command line parsing */
44 static struct hstate * __initdata parsed_hstate;
45 static unsigned long __initdata default_hstate_max_huge_pages;
46 static unsigned long __initdata default_hstate_size;
48 #define for_each_hstate(h) \
49 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
52 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
54 static DEFINE_SPINLOCK(hugetlb_lock);
57 * Region tracking -- allows tracking of reservations and instantiated pages
58 * across the pages in a mapping.
60 * The region data structures are protected by a combination of the mmap_sem
61 * and the hugetlb_instantion_mutex. To access or modify a region the caller
62 * must either hold the mmap_sem for write, or the mmap_sem for read and
63 * the hugetlb_instantiation mutex:
65 * down_write(&mm->mmap_sem);
67 * down_read(&mm->mmap_sem);
68 * mutex_lock(&hugetlb_instantiation_mutex);
71 struct list_head link;
76 static long region_add(struct list_head *head, long f, long t)
78 struct file_region *rg, *nrg, *trg;
80 /* Locate the region we are either in or before. */
81 list_for_each_entry(rg, head, link)
85 /* Round our left edge to the current segment if it encloses us. */
89 /* Check for and consume any regions we now overlap with. */
91 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
92 if (&rg->link == head)
97 /* If this area reaches higher then extend our area to
98 * include it completely. If this is not the first area
99 * which we intend to reuse, free it. */
112 static long region_chg(struct list_head *head, long f, long t)
114 struct file_region *rg, *nrg;
117 /* Locate the region we are before or in. */
118 list_for_each_entry(rg, head, link)
122 /* If we are below the current region then a new region is required.
123 * Subtle, allocate a new region at the position but make it zero
124 * size such that we can guarantee to record the reservation. */
125 if (&rg->link == head || t < rg->from) {
126 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
131 INIT_LIST_HEAD(&nrg->link);
132 list_add(&nrg->link, rg->link.prev);
137 /* Round our left edge to the current segment if it encloses us. */
142 /* Check for and consume any regions we now overlap with. */
143 list_for_each_entry(rg, rg->link.prev, link) {
144 if (&rg->link == head)
149 /* We overlap with this area, if it extends futher than
150 * us then we must extend ourselves. Account for its
151 * existing reservation. */
156 chg -= rg->to - rg->from;
161 static long region_truncate(struct list_head *head, long end)
163 struct file_region *rg, *trg;
166 /* Locate the region we are either in or before. */
167 list_for_each_entry(rg, head, link)
170 if (&rg->link == head)
173 /* If we are in the middle of a region then adjust it. */
174 if (end > rg->from) {
177 rg = list_entry(rg->link.next, typeof(*rg), link);
180 /* Drop any remaining regions. */
181 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
182 if (&rg->link == head)
184 chg += rg->to - rg->from;
191 static long region_count(struct list_head *head, long f, long t)
193 struct file_region *rg;
196 /* Locate each segment we overlap with, and count that overlap. */
197 list_for_each_entry(rg, head, link) {
206 seg_from = max(rg->from, f);
207 seg_to = min(rg->to, t);
209 chg += seg_to - seg_from;
216 * Convert the address within this vma to the page offset within
217 * the mapping, in pagecache page units; huge pages here.
219 static pgoff_t vma_hugecache_offset(struct hstate *h,
220 struct vm_area_struct *vma, unsigned long address)
222 return ((address - vma->vm_start) >> huge_page_shift(h)) +
223 (vma->vm_pgoff >> huge_page_order(h));
226 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
227 unsigned long address)
229 return vma_hugecache_offset(hstate_vma(vma), vma, address);
233 * Return the size of the pages allocated when backing a VMA. In the majority
234 * cases this will be same size as used by the page table entries.
236 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
238 struct hstate *hstate;
240 if (!is_vm_hugetlb_page(vma))
243 hstate = hstate_vma(vma);
245 return 1UL << (hstate->order + PAGE_SHIFT);
247 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
250 * Return the page size being used by the MMU to back a VMA. In the majority
251 * of cases, the page size used by the kernel matches the MMU size. On
252 * architectures where it differs, an architecture-specific version of this
253 * function is required.
255 #ifndef vma_mmu_pagesize
256 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
258 return vma_kernel_pagesize(vma);
263 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
264 * bits of the reservation map pointer, which are always clear due to
267 #define HPAGE_RESV_OWNER (1UL << 0)
268 #define HPAGE_RESV_UNMAPPED (1UL << 1)
269 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
272 * These helpers are used to track how many pages are reserved for
273 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
274 * is guaranteed to have their future faults succeed.
276 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
277 * the reserve counters are updated with the hugetlb_lock held. It is safe
278 * to reset the VMA at fork() time as it is not in use yet and there is no
279 * chance of the global counters getting corrupted as a result of the values.
281 * The private mapping reservation is represented in a subtly different
282 * manner to a shared mapping. A shared mapping has a region map associated
283 * with the underlying file, this region map represents the backing file
284 * pages which have ever had a reservation assigned which this persists even
285 * after the page is instantiated. A private mapping has a region map
286 * associated with the original mmap which is attached to all VMAs which
287 * reference it, this region map represents those offsets which have consumed
288 * reservation ie. where pages have been instantiated.
290 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
292 return (unsigned long)vma->vm_private_data;
295 static void set_vma_private_data(struct vm_area_struct *vma,
298 vma->vm_private_data = (void *)value;
303 struct list_head regions;
306 static struct resv_map *resv_map_alloc(void)
308 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
312 kref_init(&resv_map->refs);
313 INIT_LIST_HEAD(&resv_map->regions);
318 static void resv_map_release(struct kref *ref)
320 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
322 /* Clear out any active regions before we release the map. */
323 region_truncate(&resv_map->regions, 0);
327 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
329 VM_BUG_ON(!is_vm_hugetlb_page(vma));
330 if (!(vma->vm_flags & VM_MAYSHARE))
331 return (struct resv_map *)(get_vma_private_data(vma) &
336 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
338 VM_BUG_ON(!is_vm_hugetlb_page(vma));
339 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
341 set_vma_private_data(vma, (get_vma_private_data(vma) &
342 HPAGE_RESV_MASK) | (unsigned long)map);
345 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
347 VM_BUG_ON(!is_vm_hugetlb_page(vma));
348 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
350 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
353 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
355 VM_BUG_ON(!is_vm_hugetlb_page(vma));
357 return (get_vma_private_data(vma) & flag) != 0;
360 /* Decrement the reserved pages in the hugepage pool by one */
361 static void decrement_hugepage_resv_vma(struct hstate *h,
362 struct vm_area_struct *vma)
364 if (vma->vm_flags & VM_NORESERVE)
367 if (vma->vm_flags & VM_MAYSHARE) {
368 /* Shared mappings always use reserves */
369 h->resv_huge_pages--;
370 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
372 * Only the process that called mmap() has reserves for
375 h->resv_huge_pages--;
379 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
380 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
382 VM_BUG_ON(!is_vm_hugetlb_page(vma));
383 if (!(vma->vm_flags & VM_MAYSHARE))
384 vma->vm_private_data = (void *)0;
387 /* Returns true if the VMA has associated reserve pages */
388 static int vma_has_reserves(struct vm_area_struct *vma)
390 if (vma->vm_flags & VM_MAYSHARE)
392 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
397 static void copy_gigantic_page(struct page *dst, struct page *src)
400 struct hstate *h = page_hstate(src);
401 struct page *dst_base = dst;
402 struct page *src_base = src;
404 for (i = 0; i < pages_per_huge_page(h); ) {
406 copy_highpage(dst, src);
409 dst = mem_map_next(dst, dst_base, i);
410 src = mem_map_next(src, src_base, i);
414 void copy_huge_page(struct page *dst, struct page *src)
417 struct hstate *h = page_hstate(src);
419 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
420 copy_gigantic_page(dst, src);
425 for (i = 0; i < pages_per_huge_page(h); i++) {
427 copy_highpage(dst + i, src + i);
431 static void enqueue_huge_page(struct hstate *h, struct page *page)
433 int nid = page_to_nid(page);
434 list_add(&page->lru, &h->hugepage_freelists[nid]);
435 h->free_huge_pages++;
436 h->free_huge_pages_node[nid]++;
439 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
443 if (list_empty(&h->hugepage_freelists[nid]))
445 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
446 list_del(&page->lru);
447 set_page_refcounted(page);
448 h->free_huge_pages--;
449 h->free_huge_pages_node[nid]--;
453 static struct page *dequeue_huge_page_vma(struct hstate *h,
454 struct vm_area_struct *vma,
455 unsigned long address, int avoid_reserve)
457 struct page *page = NULL;
458 struct mempolicy *mpol;
459 nodemask_t *nodemask;
460 struct zonelist *zonelist;
465 zonelist = huge_zonelist(vma, address,
466 htlb_alloc_mask, &mpol, &nodemask);
468 * A child process with MAP_PRIVATE mappings created by their parent
469 * have no page reserves. This check ensures that reservations are
470 * not "stolen". The child may still get SIGKILLed
472 if (!vma_has_reserves(vma) &&
473 h->free_huge_pages - h->resv_huge_pages == 0)
476 /* If reserves cannot be used, ensure enough pages are in the pool */
477 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
480 for_each_zone_zonelist_nodemask(zone, z, zonelist,
481 MAX_NR_ZONES - 1, nodemask) {
482 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
483 page = dequeue_huge_page_node(h, zone_to_nid(zone));
486 decrement_hugepage_resv_vma(h, vma);
497 static void update_and_free_page(struct hstate *h, struct page *page)
501 VM_BUG_ON(h->order >= MAX_ORDER);
504 h->nr_huge_pages_node[page_to_nid(page)]--;
505 for (i = 0; i < pages_per_huge_page(h); i++) {
506 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
507 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
508 1 << PG_private | 1<< PG_writeback);
510 set_compound_page_dtor(page, NULL);
511 set_page_refcounted(page);
512 arch_release_hugepage(page);
513 __free_pages(page, huge_page_order(h));
516 struct hstate *size_to_hstate(unsigned long size)
521 if (huge_page_size(h) == size)
527 static void free_huge_page(struct page *page)
530 * Can't pass hstate in here because it is called from the
531 * compound page destructor.
533 struct hstate *h = page_hstate(page);
534 int nid = page_to_nid(page);
535 struct address_space *mapping;
537 mapping = (struct address_space *) page_private(page);
538 set_page_private(page, 0);
539 page->mapping = NULL;
540 BUG_ON(page_count(page));
541 BUG_ON(page_mapcount(page));
542 INIT_LIST_HEAD(&page->lru);
544 spin_lock(&hugetlb_lock);
545 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
546 update_and_free_page(h, page);
547 h->surplus_huge_pages--;
548 h->surplus_huge_pages_node[nid]--;
550 enqueue_huge_page(h, page);
552 spin_unlock(&hugetlb_lock);
554 hugetlb_put_quota(mapping, 1);
557 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
559 set_compound_page_dtor(page, free_huge_page);
560 spin_lock(&hugetlb_lock);
562 h->nr_huge_pages_node[nid]++;
563 spin_unlock(&hugetlb_lock);
564 put_page(page); /* free it into the hugepage allocator */
567 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
570 int nr_pages = 1 << order;
571 struct page *p = page + 1;
573 /* we rely on prep_new_huge_page to set the destructor */
574 set_compound_order(page, order);
576 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
578 p->first_page = page;
582 int PageHuge(struct page *page)
584 compound_page_dtor *dtor;
586 if (!PageCompound(page))
589 page = compound_head(page);
590 dtor = get_compound_page_dtor(page);
592 return dtor == free_huge_page;
595 EXPORT_SYMBOL_GPL(PageHuge);
597 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
601 if (h->order >= MAX_ORDER)
604 page = alloc_pages_exact_node(nid,
605 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
606 __GFP_REPEAT|__GFP_NOWARN,
609 if (arch_prepare_hugepage(page)) {
610 __free_pages(page, huge_page_order(h));
613 prep_new_huge_page(h, page, nid);
620 * common helper functions for hstate_next_node_to_{alloc|free}.
621 * We may have allocated or freed a huge page based on a different
622 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
623 * be outside of *nodes_allowed. Ensure that we use an allowed
624 * node for alloc or free.
626 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
628 nid = next_node(nid, *nodes_allowed);
629 if (nid == MAX_NUMNODES)
630 nid = first_node(*nodes_allowed);
631 VM_BUG_ON(nid >= MAX_NUMNODES);
636 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
638 if (!node_isset(nid, *nodes_allowed))
639 nid = next_node_allowed(nid, nodes_allowed);
644 * returns the previously saved node ["this node"] from which to
645 * allocate a persistent huge page for the pool and advance the
646 * next node from which to allocate, handling wrap at end of node
649 static int hstate_next_node_to_alloc(struct hstate *h,
650 nodemask_t *nodes_allowed)
654 VM_BUG_ON(!nodes_allowed);
656 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
657 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
662 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
669 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
670 next_nid = start_nid;
673 page = alloc_fresh_huge_page_node(h, next_nid);
678 next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
679 } while (next_nid != start_nid);
682 count_vm_event(HTLB_BUDDY_PGALLOC);
684 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
690 * helper for free_pool_huge_page() - return the previously saved
691 * node ["this node"] from which to free a huge page. Advance the
692 * next node id whether or not we find a free huge page to free so
693 * that the next attempt to free addresses the next node.
695 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
699 VM_BUG_ON(!nodes_allowed);
701 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
702 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
708 * Free huge page from pool from next node to free.
709 * Attempt to keep persistent huge pages more or less
710 * balanced over allowed nodes.
711 * Called with hugetlb_lock locked.
713 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
720 start_nid = hstate_next_node_to_free(h, nodes_allowed);
721 next_nid = start_nid;
725 * If we're returning unused surplus pages, only examine
726 * nodes with surplus pages.
728 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
729 !list_empty(&h->hugepage_freelists[next_nid])) {
731 list_entry(h->hugepage_freelists[next_nid].next,
733 list_del(&page->lru);
734 h->free_huge_pages--;
735 h->free_huge_pages_node[next_nid]--;
737 h->surplus_huge_pages--;
738 h->surplus_huge_pages_node[next_nid]--;
740 update_and_free_page(h, page);
744 next_nid = hstate_next_node_to_free(h, nodes_allowed);
745 } while (next_nid != start_nid);
750 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
755 if (h->order >= MAX_ORDER)
759 * Assume we will successfully allocate the surplus page to
760 * prevent racing processes from causing the surplus to exceed
763 * This however introduces a different race, where a process B
764 * tries to grow the static hugepage pool while alloc_pages() is
765 * called by process A. B will only examine the per-node
766 * counters in determining if surplus huge pages can be
767 * converted to normal huge pages in adjust_pool_surplus(). A
768 * won't be able to increment the per-node counter, until the
769 * lock is dropped by B, but B doesn't drop hugetlb_lock until
770 * no more huge pages can be converted from surplus to normal
771 * state (and doesn't try to convert again). Thus, we have a
772 * case where a surplus huge page exists, the pool is grown, and
773 * the surplus huge page still exists after, even though it
774 * should just have been converted to a normal huge page. This
775 * does not leak memory, though, as the hugepage will be freed
776 * once it is out of use. It also does not allow the counters to
777 * go out of whack in adjust_pool_surplus() as we don't modify
778 * the node values until we've gotten the hugepage and only the
779 * per-node value is checked there.
781 spin_lock(&hugetlb_lock);
782 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
783 spin_unlock(&hugetlb_lock);
787 h->surplus_huge_pages++;
789 spin_unlock(&hugetlb_lock);
791 if (nid == NUMA_NO_NODE)
792 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
793 __GFP_REPEAT|__GFP_NOWARN,
796 page = alloc_pages_exact_node(nid,
797 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
798 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
800 if (page && arch_prepare_hugepage(page)) {
801 __free_pages(page, huge_page_order(h));
805 spin_lock(&hugetlb_lock);
807 r_nid = page_to_nid(page);
808 set_compound_page_dtor(page, free_huge_page);
810 * We incremented the global counters already
812 h->nr_huge_pages_node[r_nid]++;
813 h->surplus_huge_pages_node[r_nid]++;
814 __count_vm_event(HTLB_BUDDY_PGALLOC);
817 h->surplus_huge_pages--;
818 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
820 spin_unlock(&hugetlb_lock);
826 * This allocation function is useful in the context where vma is irrelevant.
827 * E.g. soft-offlining uses this function because it only cares physical
828 * address of error page.
830 struct page *alloc_huge_page_node(struct hstate *h, int nid)
834 spin_lock(&hugetlb_lock);
835 page = dequeue_huge_page_node(h, nid);
836 spin_unlock(&hugetlb_lock);
839 page = alloc_buddy_huge_page(h, nid);
845 * Increase the hugetlb pool such that it can accomodate a reservation
848 static int gather_surplus_pages(struct hstate *h, int delta)
850 struct list_head surplus_list;
851 struct page *page, *tmp;
853 int needed, allocated;
855 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
857 h->resv_huge_pages += delta;
862 INIT_LIST_HEAD(&surplus_list);
866 spin_unlock(&hugetlb_lock);
867 for (i = 0; i < needed; i++) {
868 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
871 * We were not able to allocate enough pages to
872 * satisfy the entire reservation so we free what
873 * we've allocated so far.
877 list_add(&page->lru, &surplus_list);
882 * After retaking hugetlb_lock, we need to recalculate 'needed'
883 * because either resv_huge_pages or free_huge_pages may have changed.
885 spin_lock(&hugetlb_lock);
886 needed = (h->resv_huge_pages + delta) -
887 (h->free_huge_pages + allocated);
892 * The surplus_list now contains _at_least_ the number of extra pages
893 * needed to accomodate the reservation. Add the appropriate number
894 * of pages to the hugetlb pool and free the extras back to the buddy
895 * allocator. Commit the entire reservation here to prevent another
896 * process from stealing the pages as they are added to the pool but
897 * before they are reserved.
900 h->resv_huge_pages += delta;
903 spin_unlock(&hugetlb_lock);
904 /* Free the needed pages to the hugetlb pool */
905 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
908 list_del(&page->lru);
910 * This page is now managed by the hugetlb allocator and has
911 * no users -- drop the buddy allocator's reference.
913 put_page_testzero(page);
914 VM_BUG_ON(page_count(page));
915 enqueue_huge_page(h, page);
918 /* Free unnecessary surplus pages to the buddy allocator */
920 if (!list_empty(&surplus_list)) {
921 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
922 list_del(&page->lru);
926 spin_lock(&hugetlb_lock);
932 * When releasing a hugetlb pool reservation, any surplus pages that were
933 * allocated to satisfy the reservation must be explicitly freed if they were
935 * Called with hugetlb_lock held.
937 static void return_unused_surplus_pages(struct hstate *h,
938 unsigned long unused_resv_pages)
940 unsigned long nr_pages;
942 /* Uncommit the reservation */
943 h->resv_huge_pages -= unused_resv_pages;
945 /* Cannot return gigantic pages currently */
946 if (h->order >= MAX_ORDER)
949 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
952 * We want to release as many surplus pages as possible, spread
953 * evenly across all nodes with memory. Iterate across these nodes
954 * until we can no longer free unreserved surplus pages. This occurs
955 * when the nodes with surplus pages have no free pages.
956 * free_pool_huge_page() will balance the the freed pages across the
957 * on-line nodes with memory and will handle the hstate accounting.
960 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
966 * Determine if the huge page at addr within the vma has an associated
967 * reservation. Where it does not we will need to logically increase
968 * reservation and actually increase quota before an allocation can occur.
969 * Where any new reservation would be required the reservation change is
970 * prepared, but not committed. Once the page has been quota'd allocated
971 * an instantiated the change should be committed via vma_commit_reservation.
972 * No action is required on failure.
974 static long vma_needs_reservation(struct hstate *h,
975 struct vm_area_struct *vma, unsigned long addr)
977 struct address_space *mapping = vma->vm_file->f_mapping;
978 struct inode *inode = mapping->host;
980 if (vma->vm_flags & VM_MAYSHARE) {
981 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
982 return region_chg(&inode->i_mapping->private_list,
985 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
990 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
991 struct resv_map *reservations = vma_resv_map(vma);
993 err = region_chg(&reservations->regions, idx, idx + 1);
999 static void vma_commit_reservation(struct hstate *h,
1000 struct vm_area_struct *vma, unsigned long addr)
1002 struct address_space *mapping = vma->vm_file->f_mapping;
1003 struct inode *inode = mapping->host;
1005 if (vma->vm_flags & VM_MAYSHARE) {
1006 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1007 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1009 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1010 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1011 struct resv_map *reservations = vma_resv_map(vma);
1013 /* Mark this page used in the map. */
1014 region_add(&reservations->regions, idx, idx + 1);
1018 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1019 unsigned long addr, int avoid_reserve)
1021 struct hstate *h = hstate_vma(vma);
1023 struct address_space *mapping = vma->vm_file->f_mapping;
1024 struct inode *inode = mapping->host;
1028 * Processes that did not create the mapping will have no reserves and
1029 * will not have accounted against quota. Check that the quota can be
1030 * made before satisfying the allocation
1031 * MAP_NORESERVE mappings may also need pages and quota allocated
1032 * if no reserve mapping overlaps.
1034 chg = vma_needs_reservation(h, vma, addr);
1036 return ERR_PTR(chg);
1038 if (hugetlb_get_quota(inode->i_mapping, chg))
1039 return ERR_PTR(-ENOSPC);
1041 spin_lock(&hugetlb_lock);
1042 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1043 spin_unlock(&hugetlb_lock);
1046 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1048 hugetlb_put_quota(inode->i_mapping, chg);
1049 return ERR_PTR(-VM_FAULT_SIGBUS);
1053 set_page_private(page, (unsigned long) mapping);
1055 vma_commit_reservation(h, vma, addr);
1060 int __weak alloc_bootmem_huge_page(struct hstate *h)
1062 struct huge_bootmem_page *m;
1063 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1068 addr = __alloc_bootmem_node_nopanic(
1069 NODE_DATA(hstate_next_node_to_alloc(h,
1070 &node_states[N_HIGH_MEMORY])),
1071 huge_page_size(h), huge_page_size(h), 0);
1075 * Use the beginning of the huge page to store the
1076 * huge_bootmem_page struct (until gather_bootmem
1077 * puts them into the mem_map).
1087 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1088 /* Put them into a private list first because mem_map is not up yet */
1089 list_add(&m->list, &huge_boot_pages);
1094 static void prep_compound_huge_page(struct page *page, int order)
1096 if (unlikely(order > (MAX_ORDER - 1)))
1097 prep_compound_gigantic_page(page, order);
1099 prep_compound_page(page, order);
1102 /* Put bootmem huge pages into the standard lists after mem_map is up */
1103 static void __init gather_bootmem_prealloc(void)
1105 struct huge_bootmem_page *m;
1107 list_for_each_entry(m, &huge_boot_pages, list) {
1108 struct page *page = virt_to_page(m);
1109 struct hstate *h = m->hstate;
1110 __ClearPageReserved(page);
1111 WARN_ON(page_count(page) != 1);
1112 prep_compound_huge_page(page, h->order);
1113 prep_new_huge_page(h, page, page_to_nid(page));
1117 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1121 for (i = 0; i < h->max_huge_pages; ++i) {
1122 if (h->order >= MAX_ORDER) {
1123 if (!alloc_bootmem_huge_page(h))
1125 } else if (!alloc_fresh_huge_page(h,
1126 &node_states[N_HIGH_MEMORY]))
1129 h->max_huge_pages = i;
1132 static void __init hugetlb_init_hstates(void)
1136 for_each_hstate(h) {
1137 /* oversize hugepages were init'ed in early boot */
1138 if (h->order < MAX_ORDER)
1139 hugetlb_hstate_alloc_pages(h);
1143 static char * __init memfmt(char *buf, unsigned long n)
1145 if (n >= (1UL << 30))
1146 sprintf(buf, "%lu GB", n >> 30);
1147 else if (n >= (1UL << 20))
1148 sprintf(buf, "%lu MB", n >> 20);
1150 sprintf(buf, "%lu KB", n >> 10);
1154 static void __init report_hugepages(void)
1158 for_each_hstate(h) {
1160 printk(KERN_INFO "HugeTLB registered %s page size, "
1161 "pre-allocated %ld pages\n",
1162 memfmt(buf, huge_page_size(h)),
1163 h->free_huge_pages);
1167 #ifdef CONFIG_HIGHMEM
1168 static void try_to_free_low(struct hstate *h, unsigned long count,
1169 nodemask_t *nodes_allowed)
1173 if (h->order >= MAX_ORDER)
1176 for_each_node_mask(i, *nodes_allowed) {
1177 struct page *page, *next;
1178 struct list_head *freel = &h->hugepage_freelists[i];
1179 list_for_each_entry_safe(page, next, freel, lru) {
1180 if (count >= h->nr_huge_pages)
1182 if (PageHighMem(page))
1184 list_del(&page->lru);
1185 update_and_free_page(h, page);
1186 h->free_huge_pages--;
1187 h->free_huge_pages_node[page_to_nid(page)]--;
1192 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1193 nodemask_t *nodes_allowed)
1199 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1200 * balanced by operating on them in a round-robin fashion.
1201 * Returns 1 if an adjustment was made.
1203 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1206 int start_nid, next_nid;
1209 VM_BUG_ON(delta != -1 && delta != 1);
1212 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1214 start_nid = hstate_next_node_to_free(h, nodes_allowed);
1215 next_nid = start_nid;
1221 * To shrink on this node, there must be a surplus page
1223 if (!h->surplus_huge_pages_node[nid]) {
1224 next_nid = hstate_next_node_to_alloc(h,
1231 * Surplus cannot exceed the total number of pages
1233 if (h->surplus_huge_pages_node[nid] >=
1234 h->nr_huge_pages_node[nid]) {
1235 next_nid = hstate_next_node_to_free(h,
1241 h->surplus_huge_pages += delta;
1242 h->surplus_huge_pages_node[nid] += delta;
1245 } while (next_nid != start_nid);
1250 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1251 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1252 nodemask_t *nodes_allowed)
1254 unsigned long min_count, ret;
1256 if (h->order >= MAX_ORDER)
1257 return h->max_huge_pages;
1260 * Increase the pool size
1261 * First take pages out of surplus state. Then make up the
1262 * remaining difference by allocating fresh huge pages.
1264 * We might race with alloc_buddy_huge_page() here and be unable
1265 * to convert a surplus huge page to a normal huge page. That is
1266 * not critical, though, it just means the overall size of the
1267 * pool might be one hugepage larger than it needs to be, but
1268 * within all the constraints specified by the sysctls.
1270 spin_lock(&hugetlb_lock);
1271 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1272 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1276 while (count > persistent_huge_pages(h)) {
1278 * If this allocation races such that we no longer need the
1279 * page, free_huge_page will handle it by freeing the page
1280 * and reducing the surplus.
1282 spin_unlock(&hugetlb_lock);
1283 ret = alloc_fresh_huge_page(h, nodes_allowed);
1284 spin_lock(&hugetlb_lock);
1288 /* Bail for signals. Probably ctrl-c from user */
1289 if (signal_pending(current))
1294 * Decrease the pool size
1295 * First return free pages to the buddy allocator (being careful
1296 * to keep enough around to satisfy reservations). Then place
1297 * pages into surplus state as needed so the pool will shrink
1298 * to the desired size as pages become free.
1300 * By placing pages into the surplus state independent of the
1301 * overcommit value, we are allowing the surplus pool size to
1302 * exceed overcommit. There are few sane options here. Since
1303 * alloc_buddy_huge_page() is checking the global counter,
1304 * though, we'll note that we're not allowed to exceed surplus
1305 * and won't grow the pool anywhere else. Not until one of the
1306 * sysctls are changed, or the surplus pages go out of use.
1308 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1309 min_count = max(count, min_count);
1310 try_to_free_low(h, min_count, nodes_allowed);
1311 while (min_count < persistent_huge_pages(h)) {
1312 if (!free_pool_huge_page(h, nodes_allowed, 0))
1315 while (count < persistent_huge_pages(h)) {
1316 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1320 ret = persistent_huge_pages(h);
1321 spin_unlock(&hugetlb_lock);
1325 #define HSTATE_ATTR_RO(_name) \
1326 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1328 #define HSTATE_ATTR(_name) \
1329 static struct kobj_attribute _name##_attr = \
1330 __ATTR(_name, 0644, _name##_show, _name##_store)
1332 static struct kobject *hugepages_kobj;
1333 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1335 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1337 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1341 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1342 if (hstate_kobjs[i] == kobj) {
1344 *nidp = NUMA_NO_NODE;
1348 return kobj_to_node_hstate(kobj, nidp);
1351 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1352 struct kobj_attribute *attr, char *buf)
1355 unsigned long nr_huge_pages;
1358 h = kobj_to_hstate(kobj, &nid);
1359 if (nid == NUMA_NO_NODE)
1360 nr_huge_pages = h->nr_huge_pages;
1362 nr_huge_pages = h->nr_huge_pages_node[nid];
1364 return sprintf(buf, "%lu\n", nr_huge_pages);
1367 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1368 struct kobject *kobj, struct kobj_attribute *attr,
1369 const char *buf, size_t len)
1373 unsigned long count;
1375 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1377 err = strict_strtoul(buf, 10, &count);
1379 err = 0; /* This seems wrong */
1383 h = kobj_to_hstate(kobj, &nid);
1384 if (h->order >= MAX_ORDER) {
1389 if (nid == NUMA_NO_NODE) {
1391 * global hstate attribute
1393 if (!(obey_mempolicy &&
1394 init_nodemask_of_mempolicy(nodes_allowed))) {
1395 NODEMASK_FREE(nodes_allowed);
1396 nodes_allowed = &node_states[N_HIGH_MEMORY];
1398 } else if (nodes_allowed) {
1400 * per node hstate attribute: adjust count to global,
1401 * but restrict alloc/free to the specified node.
1403 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1404 init_nodemask_of_node(nodes_allowed, nid);
1406 nodes_allowed = &node_states[N_HIGH_MEMORY];
1408 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1410 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1411 NODEMASK_FREE(nodes_allowed);
1415 NODEMASK_FREE(nodes_allowed);
1419 static ssize_t nr_hugepages_show(struct kobject *kobj,
1420 struct kobj_attribute *attr, char *buf)
1422 return nr_hugepages_show_common(kobj, attr, buf);
1425 static ssize_t nr_hugepages_store(struct kobject *kobj,
1426 struct kobj_attribute *attr, const char *buf, size_t len)
1428 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1430 HSTATE_ATTR(nr_hugepages);
1435 * hstate attribute for optionally mempolicy-based constraint on persistent
1436 * huge page alloc/free.
1438 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1439 struct kobj_attribute *attr, char *buf)
1441 return nr_hugepages_show_common(kobj, attr, buf);
1444 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1445 struct kobj_attribute *attr, const char *buf, size_t len)
1447 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1449 HSTATE_ATTR(nr_hugepages_mempolicy);
1453 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1454 struct kobj_attribute *attr, char *buf)
1456 struct hstate *h = kobj_to_hstate(kobj, NULL);
1457 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1460 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1461 struct kobj_attribute *attr, const char *buf, size_t count)
1464 unsigned long input;
1465 struct hstate *h = kobj_to_hstate(kobj, NULL);
1467 if (h->order >= MAX_ORDER)
1470 err = strict_strtoul(buf, 10, &input);
1474 spin_lock(&hugetlb_lock);
1475 h->nr_overcommit_huge_pages = input;
1476 spin_unlock(&hugetlb_lock);
1480 HSTATE_ATTR(nr_overcommit_hugepages);
1482 static ssize_t free_hugepages_show(struct kobject *kobj,
1483 struct kobj_attribute *attr, char *buf)
1486 unsigned long free_huge_pages;
1489 h = kobj_to_hstate(kobj, &nid);
1490 if (nid == NUMA_NO_NODE)
1491 free_huge_pages = h->free_huge_pages;
1493 free_huge_pages = h->free_huge_pages_node[nid];
1495 return sprintf(buf, "%lu\n", free_huge_pages);
1497 HSTATE_ATTR_RO(free_hugepages);
1499 static ssize_t resv_hugepages_show(struct kobject *kobj,
1500 struct kobj_attribute *attr, char *buf)
1502 struct hstate *h = kobj_to_hstate(kobj, NULL);
1503 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1505 HSTATE_ATTR_RO(resv_hugepages);
1507 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1508 struct kobj_attribute *attr, char *buf)
1511 unsigned long surplus_huge_pages;
1514 h = kobj_to_hstate(kobj, &nid);
1515 if (nid == NUMA_NO_NODE)
1516 surplus_huge_pages = h->surplus_huge_pages;
1518 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1520 return sprintf(buf, "%lu\n", surplus_huge_pages);
1522 HSTATE_ATTR_RO(surplus_hugepages);
1524 static struct attribute *hstate_attrs[] = {
1525 &nr_hugepages_attr.attr,
1526 &nr_overcommit_hugepages_attr.attr,
1527 &free_hugepages_attr.attr,
1528 &resv_hugepages_attr.attr,
1529 &surplus_hugepages_attr.attr,
1531 &nr_hugepages_mempolicy_attr.attr,
1536 static struct attribute_group hstate_attr_group = {
1537 .attrs = hstate_attrs,
1540 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1541 struct kobject **hstate_kobjs,
1542 struct attribute_group *hstate_attr_group)
1545 int hi = h - hstates;
1547 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1548 if (!hstate_kobjs[hi])
1551 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1553 kobject_put(hstate_kobjs[hi]);
1558 static void __init hugetlb_sysfs_init(void)
1563 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1564 if (!hugepages_kobj)
1567 for_each_hstate(h) {
1568 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1569 hstate_kobjs, &hstate_attr_group);
1571 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1579 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1580 * with node sysdevs in node_devices[] using a parallel array. The array
1581 * index of a node sysdev or _hstate == node id.
1582 * This is here to avoid any static dependency of the node sysdev driver, in
1583 * the base kernel, on the hugetlb module.
1585 struct node_hstate {
1586 struct kobject *hugepages_kobj;
1587 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1589 struct node_hstate node_hstates[MAX_NUMNODES];
1592 * A subset of global hstate attributes for node sysdevs
1594 static struct attribute *per_node_hstate_attrs[] = {
1595 &nr_hugepages_attr.attr,
1596 &free_hugepages_attr.attr,
1597 &surplus_hugepages_attr.attr,
1601 static struct attribute_group per_node_hstate_attr_group = {
1602 .attrs = per_node_hstate_attrs,
1606 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1607 * Returns node id via non-NULL nidp.
1609 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1613 for (nid = 0; nid < nr_node_ids; nid++) {
1614 struct node_hstate *nhs = &node_hstates[nid];
1616 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1617 if (nhs->hstate_kobjs[i] == kobj) {
1629 * Unregister hstate attributes from a single node sysdev.
1630 * No-op if no hstate attributes attached.
1632 void hugetlb_unregister_node(struct node *node)
1635 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1637 if (!nhs->hugepages_kobj)
1638 return; /* no hstate attributes */
1641 if (nhs->hstate_kobjs[h - hstates]) {
1642 kobject_put(nhs->hstate_kobjs[h - hstates]);
1643 nhs->hstate_kobjs[h - hstates] = NULL;
1646 kobject_put(nhs->hugepages_kobj);
1647 nhs->hugepages_kobj = NULL;
1651 * hugetlb module exit: unregister hstate attributes from node sysdevs
1654 static void hugetlb_unregister_all_nodes(void)
1659 * disable node sysdev registrations.
1661 register_hugetlbfs_with_node(NULL, NULL);
1664 * remove hstate attributes from any nodes that have them.
1666 for (nid = 0; nid < nr_node_ids; nid++)
1667 hugetlb_unregister_node(&node_devices[nid]);
1671 * Register hstate attributes for a single node sysdev.
1672 * No-op if attributes already registered.
1674 void hugetlb_register_node(struct node *node)
1677 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1680 if (nhs->hugepages_kobj)
1681 return; /* already allocated */
1683 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1684 &node->sysdev.kobj);
1685 if (!nhs->hugepages_kobj)
1688 for_each_hstate(h) {
1689 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1691 &per_node_hstate_attr_group);
1693 printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
1695 h->name, node->sysdev.id);
1696 hugetlb_unregister_node(node);
1703 * hugetlb init time: register hstate attributes for all registered node
1704 * sysdevs of nodes that have memory. All on-line nodes should have
1705 * registered their associated sysdev by this time.
1707 static void hugetlb_register_all_nodes(void)
1711 for_each_node_state(nid, N_HIGH_MEMORY) {
1712 struct node *node = &node_devices[nid];
1713 if (node->sysdev.id == nid)
1714 hugetlb_register_node(node);
1718 * Let the node sysdev driver know we're here so it can
1719 * [un]register hstate attributes on node hotplug.
1721 register_hugetlbfs_with_node(hugetlb_register_node,
1722 hugetlb_unregister_node);
1724 #else /* !CONFIG_NUMA */
1726 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1734 static void hugetlb_unregister_all_nodes(void) { }
1736 static void hugetlb_register_all_nodes(void) { }
1740 static void __exit hugetlb_exit(void)
1744 hugetlb_unregister_all_nodes();
1746 for_each_hstate(h) {
1747 kobject_put(hstate_kobjs[h - hstates]);
1750 kobject_put(hugepages_kobj);
1752 module_exit(hugetlb_exit);
1754 static int __init hugetlb_init(void)
1756 /* Some platform decide whether they support huge pages at boot
1757 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1758 * there is no such support
1760 if (HPAGE_SHIFT == 0)
1763 if (!size_to_hstate(default_hstate_size)) {
1764 default_hstate_size = HPAGE_SIZE;
1765 if (!size_to_hstate(default_hstate_size))
1766 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1768 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1769 if (default_hstate_max_huge_pages)
1770 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1772 hugetlb_init_hstates();
1774 gather_bootmem_prealloc();
1778 hugetlb_sysfs_init();
1780 hugetlb_register_all_nodes();
1784 module_init(hugetlb_init);
1786 /* Should be called on processing a hugepagesz=... option */
1787 void __init hugetlb_add_hstate(unsigned order)
1792 if (size_to_hstate(PAGE_SIZE << order)) {
1793 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1796 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1798 h = &hstates[max_hstate++];
1800 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1801 h->nr_huge_pages = 0;
1802 h->free_huge_pages = 0;
1803 for (i = 0; i < MAX_NUMNODES; ++i)
1804 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1805 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
1806 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1807 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1808 huge_page_size(h)/1024);
1813 static int __init hugetlb_nrpages_setup(char *s)
1816 static unsigned long *last_mhp;
1819 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1820 * so this hugepages= parameter goes to the "default hstate".
1823 mhp = &default_hstate_max_huge_pages;
1825 mhp = &parsed_hstate->max_huge_pages;
1827 if (mhp == last_mhp) {
1828 printk(KERN_WARNING "hugepages= specified twice without "
1829 "interleaving hugepagesz=, ignoring\n");
1833 if (sscanf(s, "%lu", mhp) <= 0)
1837 * Global state is always initialized later in hugetlb_init.
1838 * But we need to allocate >= MAX_ORDER hstates here early to still
1839 * use the bootmem allocator.
1841 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1842 hugetlb_hstate_alloc_pages(parsed_hstate);
1848 __setup("hugepages=", hugetlb_nrpages_setup);
1850 static int __init hugetlb_default_setup(char *s)
1852 default_hstate_size = memparse(s, &s);
1855 __setup("default_hugepagesz=", hugetlb_default_setup);
1857 static unsigned int cpuset_mems_nr(unsigned int *array)
1860 unsigned int nr = 0;
1862 for_each_node_mask(node, cpuset_current_mems_allowed)
1868 #ifdef CONFIG_SYSCTL
1869 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
1870 struct ctl_table *table, int write,
1871 void __user *buffer, size_t *length, loff_t *ppos)
1873 struct hstate *h = &default_hstate;
1878 tmp = h->max_huge_pages;
1880 if (write && h->order >= MAX_ORDER)
1884 table->maxlen = sizeof(unsigned long);
1885 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
1890 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
1891 GFP_KERNEL | __GFP_NORETRY);
1892 if (!(obey_mempolicy &&
1893 init_nodemask_of_mempolicy(nodes_allowed))) {
1894 NODEMASK_FREE(nodes_allowed);
1895 nodes_allowed = &node_states[N_HIGH_MEMORY];
1897 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
1899 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1900 NODEMASK_FREE(nodes_allowed);
1906 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1907 void __user *buffer, size_t *length, loff_t *ppos)
1910 return hugetlb_sysctl_handler_common(false, table, write,
1911 buffer, length, ppos);
1915 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
1916 void __user *buffer, size_t *length, loff_t *ppos)
1918 return hugetlb_sysctl_handler_common(true, table, write,
1919 buffer, length, ppos);
1921 #endif /* CONFIG_NUMA */
1923 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1924 void __user *buffer,
1925 size_t *length, loff_t *ppos)
1927 proc_dointvec(table, write, buffer, length, ppos);
1928 if (hugepages_treat_as_movable)
1929 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1931 htlb_alloc_mask = GFP_HIGHUSER;
1935 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1936 void __user *buffer,
1937 size_t *length, loff_t *ppos)
1939 struct hstate *h = &default_hstate;
1944 tmp = h->nr_overcommit_huge_pages;
1946 if (write && h->order >= MAX_ORDER)
1950 table->maxlen = sizeof(unsigned long);
1951 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
1956 spin_lock(&hugetlb_lock);
1957 h->nr_overcommit_huge_pages = tmp;
1958 spin_unlock(&hugetlb_lock);
1964 #endif /* CONFIG_SYSCTL */
1966 void hugetlb_report_meminfo(struct seq_file *m)
1968 struct hstate *h = &default_hstate;
1970 "HugePages_Total: %5lu\n"
1971 "HugePages_Free: %5lu\n"
1972 "HugePages_Rsvd: %5lu\n"
1973 "HugePages_Surp: %5lu\n"
1974 "Hugepagesize: %8lu kB\n",
1978 h->surplus_huge_pages,
1979 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1982 int hugetlb_report_node_meminfo(int nid, char *buf)
1984 struct hstate *h = &default_hstate;
1986 "Node %d HugePages_Total: %5u\n"
1987 "Node %d HugePages_Free: %5u\n"
1988 "Node %d HugePages_Surp: %5u\n",
1989 nid, h->nr_huge_pages_node[nid],
1990 nid, h->free_huge_pages_node[nid],
1991 nid, h->surplus_huge_pages_node[nid]);
1994 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1995 unsigned long hugetlb_total_pages(void)
1997 struct hstate *h = &default_hstate;
1998 return h->nr_huge_pages * pages_per_huge_page(h);
2001 static int hugetlb_acct_memory(struct hstate *h, long delta)
2005 spin_lock(&hugetlb_lock);
2007 * When cpuset is configured, it breaks the strict hugetlb page
2008 * reservation as the accounting is done on a global variable. Such
2009 * reservation is completely rubbish in the presence of cpuset because
2010 * the reservation is not checked against page availability for the
2011 * current cpuset. Application can still potentially OOM'ed by kernel
2012 * with lack of free htlb page in cpuset that the task is in.
2013 * Attempt to enforce strict accounting with cpuset is almost
2014 * impossible (or too ugly) because cpuset is too fluid that
2015 * task or memory node can be dynamically moved between cpusets.
2017 * The change of semantics for shared hugetlb mapping with cpuset is
2018 * undesirable. However, in order to preserve some of the semantics,
2019 * we fall back to check against current free page availability as
2020 * a best attempt and hopefully to minimize the impact of changing
2021 * semantics that cpuset has.
2024 if (gather_surplus_pages(h, delta) < 0)
2027 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2028 return_unused_surplus_pages(h, delta);
2035 return_unused_surplus_pages(h, (unsigned long) -delta);
2038 spin_unlock(&hugetlb_lock);
2042 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2044 struct resv_map *reservations = vma_resv_map(vma);
2047 * This new VMA should share its siblings reservation map if present.
2048 * The VMA will only ever have a valid reservation map pointer where
2049 * it is being copied for another still existing VMA. As that VMA
2050 * has a reference to the reservation map it cannot dissappear until
2051 * after this open call completes. It is therefore safe to take a
2052 * new reference here without additional locking.
2055 kref_get(&reservations->refs);
2058 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2060 struct hstate *h = hstate_vma(vma);
2061 struct resv_map *reservations = vma_resv_map(vma);
2062 unsigned long reserve;
2063 unsigned long start;
2067 start = vma_hugecache_offset(h, vma, vma->vm_start);
2068 end = vma_hugecache_offset(h, vma, vma->vm_end);
2070 reserve = (end - start) -
2071 region_count(&reservations->regions, start, end);
2073 kref_put(&reservations->refs, resv_map_release);
2076 hugetlb_acct_memory(h, -reserve);
2077 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
2083 * We cannot handle pagefaults against hugetlb pages at all. They cause
2084 * handle_mm_fault() to try to instantiate regular-sized pages in the
2085 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2088 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2094 const struct vm_operations_struct hugetlb_vm_ops = {
2095 .fault = hugetlb_vm_op_fault,
2096 .open = hugetlb_vm_op_open,
2097 .close = hugetlb_vm_op_close,
2100 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2107 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
2109 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
2111 entry = pte_mkyoung(entry);
2112 entry = pte_mkhuge(entry);
2117 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2118 unsigned long address, pte_t *ptep)
2122 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2123 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
2124 update_mmu_cache(vma, address, ptep);
2129 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2130 struct vm_area_struct *vma)
2132 pte_t *src_pte, *dst_pte, entry;
2133 struct page *ptepage;
2136 struct hstate *h = hstate_vma(vma);
2137 unsigned long sz = huge_page_size(h);
2139 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2141 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2142 src_pte = huge_pte_offset(src, addr);
2145 dst_pte = huge_pte_alloc(dst, addr, sz);
2149 /* If the pagetables are shared don't copy or take references */
2150 if (dst_pte == src_pte)
2153 spin_lock(&dst->page_table_lock);
2154 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2155 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2157 huge_ptep_set_wrprotect(src, addr, src_pte);
2158 entry = huge_ptep_get(src_pte);
2159 ptepage = pte_page(entry);
2161 page_dup_rmap(ptepage);
2162 set_huge_pte_at(dst, addr, dst_pte, entry);
2164 spin_unlock(&src->page_table_lock);
2165 spin_unlock(&dst->page_table_lock);
2173 static int is_hugetlb_entry_migration(pte_t pte)
2177 if (huge_pte_none(pte) || pte_present(pte))
2179 swp = pte_to_swp_entry(pte);
2180 if (non_swap_entry(swp) && is_migration_entry(swp)) {
2186 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2190 if (huge_pte_none(pte) || pte_present(pte))
2192 swp = pte_to_swp_entry(pte);
2193 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) {
2199 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2200 unsigned long end, struct page *ref_page)
2202 struct mm_struct *mm = vma->vm_mm;
2203 unsigned long address;
2208 struct hstate *h = hstate_vma(vma);
2209 unsigned long sz = huge_page_size(h);
2212 * A page gathering list, protected by per file i_mmap_lock. The
2213 * lock is used to avoid list corruption from multiple unmapping
2214 * of the same page since we are using page->lru.
2216 LIST_HEAD(page_list);
2218 WARN_ON(!is_vm_hugetlb_page(vma));
2219 BUG_ON(start & ~huge_page_mask(h));
2220 BUG_ON(end & ~huge_page_mask(h));
2222 mmu_notifier_invalidate_range_start(mm, start, end);
2223 spin_lock(&mm->page_table_lock);
2224 for (address = start; address < end; address += sz) {
2225 ptep = huge_pte_offset(mm, address);
2229 if (huge_pmd_unshare(mm, &address, ptep))
2233 * If a reference page is supplied, it is because a specific
2234 * page is being unmapped, not a range. Ensure the page we
2235 * are about to unmap is the actual page of interest.
2238 pte = huge_ptep_get(ptep);
2239 if (huge_pte_none(pte))
2241 page = pte_page(pte);
2242 if (page != ref_page)
2246 * Mark the VMA as having unmapped its page so that
2247 * future faults in this VMA will fail rather than
2248 * looking like data was lost
2250 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2253 pte = huge_ptep_get_and_clear(mm, address, ptep);
2254 if (huge_pte_none(pte))
2258 * HWPoisoned hugepage is already unmapped and dropped reference
2260 if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
2263 page = pte_page(pte);
2265 set_page_dirty(page);
2266 list_add(&page->lru, &page_list);
2268 spin_unlock(&mm->page_table_lock);
2269 flush_tlb_range(vma, start, end);
2270 mmu_notifier_invalidate_range_end(mm, start, end);
2271 list_for_each_entry_safe(page, tmp, &page_list, lru) {
2272 page_remove_rmap(page);
2273 list_del(&page->lru);
2278 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2279 unsigned long end, struct page *ref_page)
2281 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2282 __unmap_hugepage_range(vma, start, end, ref_page);
2283 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2287 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2288 * mappping it owns the reserve page for. The intention is to unmap the page
2289 * from other VMAs and let the children be SIGKILLed if they are faulting the
2292 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2293 struct page *page, unsigned long address)
2295 struct hstate *h = hstate_vma(vma);
2296 struct vm_area_struct *iter_vma;
2297 struct address_space *mapping;
2298 struct prio_tree_iter iter;
2302 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2303 * from page cache lookup which is in HPAGE_SIZE units.
2305 address = address & huge_page_mask(h);
2306 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
2307 + (vma->vm_pgoff >> PAGE_SHIFT);
2308 mapping = (struct address_space *)page_private(page);
2311 * Take the mapping lock for the duration of the table walk. As
2312 * this mapping should be shared between all the VMAs,
2313 * __unmap_hugepage_range() is called as the lock is already held
2315 spin_lock(&mapping->i_mmap_lock);
2316 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
2317 /* Do not unmap the current VMA */
2318 if (iter_vma == vma)
2322 * Unmap the page from other VMAs without their own reserves.
2323 * They get marked to be SIGKILLed if they fault in these
2324 * areas. This is because a future no-page fault on this VMA
2325 * could insert a zeroed page instead of the data existing
2326 * from the time of fork. This would look like data corruption
2328 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2329 __unmap_hugepage_range(iter_vma,
2330 address, address + huge_page_size(h),
2333 spin_unlock(&mapping->i_mmap_lock);
2339 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2341 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2342 unsigned long address, pte_t *ptep, pte_t pte,
2343 struct page *pagecache_page)
2345 struct hstate *h = hstate_vma(vma);
2346 struct page *old_page, *new_page;
2348 int outside_reserve = 0;
2350 old_page = pte_page(pte);
2353 /* If no-one else is actually using this page, avoid the copy
2354 * and just make the page writable */
2355 avoidcopy = (page_mapcount(old_page) == 1);
2357 if (PageAnon(old_page))
2358 page_move_anon_rmap(old_page, vma, address);
2359 set_huge_ptep_writable(vma, address, ptep);
2364 * If the process that created a MAP_PRIVATE mapping is about to
2365 * perform a COW due to a shared page count, attempt to satisfy
2366 * the allocation without using the existing reserves. The pagecache
2367 * page is used to determine if the reserve at this address was
2368 * consumed or not. If reserves were used, a partial faulted mapping
2369 * at the time of fork() could consume its reserves on COW instead
2370 * of the full address range.
2372 if (!(vma->vm_flags & VM_MAYSHARE) &&
2373 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2374 old_page != pagecache_page)
2375 outside_reserve = 1;
2377 page_cache_get(old_page);
2379 /* Drop page_table_lock as buddy allocator may be called */
2380 spin_unlock(&mm->page_table_lock);
2381 new_page = alloc_huge_page(vma, address, outside_reserve);
2383 if (IS_ERR(new_page)) {
2384 page_cache_release(old_page);
2387 * If a process owning a MAP_PRIVATE mapping fails to COW,
2388 * it is due to references held by a child and an insufficient
2389 * huge page pool. To guarantee the original mappers
2390 * reliability, unmap the page from child processes. The child
2391 * may get SIGKILLed if it later faults.
2393 if (outside_reserve) {
2394 BUG_ON(huge_pte_none(pte));
2395 if (unmap_ref_private(mm, vma, old_page, address)) {
2396 BUG_ON(page_count(old_page) != 1);
2397 BUG_ON(huge_pte_none(pte));
2398 spin_lock(&mm->page_table_lock);
2399 goto retry_avoidcopy;
2404 /* Caller expects lock to be held */
2405 spin_lock(&mm->page_table_lock);
2406 return -PTR_ERR(new_page);
2410 * When the original hugepage is shared one, it does not have
2411 * anon_vma prepared.
2413 if (unlikely(anon_vma_prepare(vma))) {
2414 /* Caller expects lock to be held */
2415 spin_lock(&mm->page_table_lock);
2416 return VM_FAULT_OOM;
2419 copy_user_huge_page(new_page, old_page, address, vma,
2420 pages_per_huge_page(h));
2421 __SetPageUptodate(new_page);
2424 * Retake the page_table_lock to check for racing updates
2425 * before the page tables are altered
2427 spin_lock(&mm->page_table_lock);
2428 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2429 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2431 mmu_notifier_invalidate_range_start(mm,
2432 address & huge_page_mask(h),
2433 (address & huge_page_mask(h)) + huge_page_size(h));
2434 huge_ptep_clear_flush(vma, address, ptep);
2435 set_huge_pte_at(mm, address, ptep,
2436 make_huge_pte(vma, new_page, 1));
2437 page_remove_rmap(old_page);
2438 hugepage_add_new_anon_rmap(new_page, vma, address);
2439 /* Make the old page be freed below */
2440 new_page = old_page;
2441 mmu_notifier_invalidate_range_end(mm,
2442 address & huge_page_mask(h),
2443 (address & huge_page_mask(h)) + huge_page_size(h));
2445 page_cache_release(new_page);
2446 page_cache_release(old_page);
2450 /* Return the pagecache page at a given address within a VMA */
2451 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2452 struct vm_area_struct *vma, unsigned long address)
2454 struct address_space *mapping;
2457 mapping = vma->vm_file->f_mapping;
2458 idx = vma_hugecache_offset(h, vma, address);
2460 return find_lock_page(mapping, idx);
2464 * Return whether there is a pagecache page to back given address within VMA.
2465 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2467 static bool hugetlbfs_pagecache_present(struct hstate *h,
2468 struct vm_area_struct *vma, unsigned long address)
2470 struct address_space *mapping;
2474 mapping = vma->vm_file->f_mapping;
2475 idx = vma_hugecache_offset(h, vma, address);
2477 page = find_get_page(mapping, idx);
2480 return page != NULL;
2483 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2484 unsigned long address, pte_t *ptep, unsigned int flags)
2486 struct hstate *h = hstate_vma(vma);
2487 int ret = VM_FAULT_SIGBUS;
2491 struct address_space *mapping;
2495 * Currently, we are forced to kill the process in the event the
2496 * original mapper has unmapped pages from the child due to a failed
2497 * COW. Warn that such a situation has occured as it may not be obvious
2499 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2501 "PID %d killed due to inadequate hugepage pool\n",
2506 mapping = vma->vm_file->f_mapping;
2507 idx = vma_hugecache_offset(h, vma, address);
2510 * Use page lock to guard against racing truncation
2511 * before we get page_table_lock.
2514 page = find_lock_page(mapping, idx);
2516 size = i_size_read(mapping->host) >> huge_page_shift(h);
2519 page = alloc_huge_page(vma, address, 0);
2521 ret = -PTR_ERR(page);
2524 clear_huge_page(page, address, pages_per_huge_page(h));
2525 __SetPageUptodate(page);
2527 if (vma->vm_flags & VM_MAYSHARE) {
2529 struct inode *inode = mapping->host;
2531 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2539 spin_lock(&inode->i_lock);
2540 inode->i_blocks += blocks_per_huge_page(h);
2541 spin_unlock(&inode->i_lock);
2542 page_dup_rmap(page);
2545 if (unlikely(anon_vma_prepare(vma))) {
2547 goto backout_unlocked;
2549 hugepage_add_new_anon_rmap(page, vma, address);
2553 * If memory error occurs between mmap() and fault, some process
2554 * don't have hwpoisoned swap entry for errored virtual address.
2555 * So we need to block hugepage fault by PG_hwpoison bit check.
2557 if (unlikely(PageHWPoison(page))) {
2558 ret = VM_FAULT_HWPOISON |
2559 VM_FAULT_SET_HINDEX(h - hstates);
2560 goto backout_unlocked;
2562 page_dup_rmap(page);
2566 * If we are going to COW a private mapping later, we examine the
2567 * pending reservations for this page now. This will ensure that
2568 * any allocations necessary to record that reservation occur outside
2571 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2572 if (vma_needs_reservation(h, vma, address) < 0) {
2574 goto backout_unlocked;
2577 spin_lock(&mm->page_table_lock);
2578 size = i_size_read(mapping->host) >> huge_page_shift(h);
2583 if (!huge_pte_none(huge_ptep_get(ptep)))
2586 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2587 && (vma->vm_flags & VM_SHARED)));
2588 set_huge_pte_at(mm, address, ptep, new_pte);
2590 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2591 /* Optimization, do the COW without a second fault */
2592 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2595 spin_unlock(&mm->page_table_lock);
2601 spin_unlock(&mm->page_table_lock);
2608 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2609 unsigned long address, unsigned int flags)
2614 struct page *page = NULL;
2615 struct page *pagecache_page = NULL;
2616 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2617 struct hstate *h = hstate_vma(vma);
2619 ptep = huge_pte_offset(mm, address);
2621 entry = huge_ptep_get(ptep);
2622 if (unlikely(is_hugetlb_entry_migration(entry))) {
2623 migration_entry_wait(mm, (pmd_t *)ptep, address);
2625 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2626 return VM_FAULT_HWPOISON_LARGE |
2627 VM_FAULT_SET_HINDEX(h - hstates);
2630 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2632 return VM_FAULT_OOM;
2635 * Serialize hugepage allocation and instantiation, so that we don't
2636 * get spurious allocation failures if two CPUs race to instantiate
2637 * the same page in the page cache.
2639 mutex_lock(&hugetlb_instantiation_mutex);
2640 entry = huge_ptep_get(ptep);
2641 if (huge_pte_none(entry)) {
2642 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2649 * If we are going to COW the mapping later, we examine the pending
2650 * reservations for this page now. This will ensure that any
2651 * allocations necessary to record that reservation occur outside the
2652 * spinlock. For private mappings, we also lookup the pagecache
2653 * page now as it is used to determine if a reservation has been
2656 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2657 if (vma_needs_reservation(h, vma, address) < 0) {
2662 if (!(vma->vm_flags & VM_MAYSHARE))
2663 pagecache_page = hugetlbfs_pagecache_page(h,
2668 * hugetlb_cow() requires page locks of pte_page(entry) and
2669 * pagecache_page, so here we need take the former one
2670 * when page != pagecache_page or !pagecache_page.
2671 * Note that locking order is always pagecache_page -> page,
2672 * so no worry about deadlock.
2674 page = pte_page(entry);
2675 if (page != pagecache_page)
2678 spin_lock(&mm->page_table_lock);
2679 /* Check for a racing update before calling hugetlb_cow */
2680 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2681 goto out_page_table_lock;
2684 if (flags & FAULT_FLAG_WRITE) {
2685 if (!pte_write(entry)) {
2686 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2688 goto out_page_table_lock;
2690 entry = pte_mkdirty(entry);
2692 entry = pte_mkyoung(entry);
2693 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2694 flags & FAULT_FLAG_WRITE))
2695 update_mmu_cache(vma, address, ptep);
2697 out_page_table_lock:
2698 spin_unlock(&mm->page_table_lock);
2700 if (pagecache_page) {
2701 unlock_page(pagecache_page);
2702 put_page(pagecache_page);
2704 if (page != pagecache_page)
2708 mutex_unlock(&hugetlb_instantiation_mutex);
2713 /* Can be overriden by architectures */
2714 __attribute__((weak)) struct page *
2715 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2716 pud_t *pud, int write)
2722 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2723 struct page **pages, struct vm_area_struct **vmas,
2724 unsigned long *position, int *length, int i,
2727 unsigned long pfn_offset;
2728 unsigned long vaddr = *position;
2729 int remainder = *length;
2730 struct hstate *h = hstate_vma(vma);
2732 spin_lock(&mm->page_table_lock);
2733 while (vaddr < vma->vm_end && remainder) {
2739 * Some archs (sparc64, sh*) have multiple pte_ts to
2740 * each hugepage. We have to make sure we get the
2741 * first, for the page indexing below to work.
2743 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2744 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2747 * When coredumping, it suits get_dump_page if we just return
2748 * an error where there's an empty slot with no huge pagecache
2749 * to back it. This way, we avoid allocating a hugepage, and
2750 * the sparse dumpfile avoids allocating disk blocks, but its
2751 * huge holes still show up with zeroes where they need to be.
2753 if (absent && (flags & FOLL_DUMP) &&
2754 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2760 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2763 spin_unlock(&mm->page_table_lock);
2764 ret = hugetlb_fault(mm, vma, vaddr,
2765 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2766 spin_lock(&mm->page_table_lock);
2767 if (!(ret & VM_FAULT_ERROR))
2774 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2775 page = pte_page(huge_ptep_get(pte));
2778 pages[i] = mem_map_offset(page, pfn_offset);
2789 if (vaddr < vma->vm_end && remainder &&
2790 pfn_offset < pages_per_huge_page(h)) {
2792 * We use pfn_offset to avoid touching the pageframes
2793 * of this compound page.
2798 spin_unlock(&mm->page_table_lock);
2799 *length = remainder;
2802 return i ? i : -EFAULT;
2805 void hugetlb_change_protection(struct vm_area_struct *vma,
2806 unsigned long address, unsigned long end, pgprot_t newprot)
2808 struct mm_struct *mm = vma->vm_mm;
2809 unsigned long start = address;
2812 struct hstate *h = hstate_vma(vma);
2814 BUG_ON(address >= end);
2815 flush_cache_range(vma, address, end);
2817 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2818 spin_lock(&mm->page_table_lock);
2819 for (; address < end; address += huge_page_size(h)) {
2820 ptep = huge_pte_offset(mm, address);
2823 if (huge_pmd_unshare(mm, &address, ptep))
2825 if (!huge_pte_none(huge_ptep_get(ptep))) {
2826 pte = huge_ptep_get_and_clear(mm, address, ptep);
2827 pte = pte_mkhuge(pte_modify(pte, newprot));
2828 set_huge_pte_at(mm, address, ptep, pte);
2831 spin_unlock(&mm->page_table_lock);
2832 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2834 flush_tlb_range(vma, start, end);
2837 int hugetlb_reserve_pages(struct inode *inode,
2839 struct vm_area_struct *vma,
2843 struct hstate *h = hstate_inode(inode);
2846 * Only apply hugepage reservation if asked. At fault time, an
2847 * attempt will be made for VM_NORESERVE to allocate a page
2848 * and filesystem quota without using reserves
2850 if (acctflag & VM_NORESERVE)
2854 * Shared mappings base their reservation on the number of pages that
2855 * are already allocated on behalf of the file. Private mappings need
2856 * to reserve the full area even if read-only as mprotect() may be
2857 * called to make the mapping read-write. Assume !vma is a shm mapping
2859 if (!vma || vma->vm_flags & VM_MAYSHARE)
2860 chg = region_chg(&inode->i_mapping->private_list, from, to);
2862 struct resv_map *resv_map = resv_map_alloc();
2868 set_vma_resv_map(vma, resv_map);
2869 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2875 /* There must be enough filesystem quota for the mapping */
2876 if (hugetlb_get_quota(inode->i_mapping, chg))
2880 * Check enough hugepages are available for the reservation.
2881 * Hand back the quota if there are not
2883 ret = hugetlb_acct_memory(h, chg);
2885 hugetlb_put_quota(inode->i_mapping, chg);
2890 * Account for the reservations made. Shared mappings record regions
2891 * that have reservations as they are shared by multiple VMAs.
2892 * When the last VMA disappears, the region map says how much
2893 * the reservation was and the page cache tells how much of
2894 * the reservation was consumed. Private mappings are per-VMA and
2895 * only the consumed reservations are tracked. When the VMA
2896 * disappears, the original reservation is the VMA size and the
2897 * consumed reservations are stored in the map. Hence, nothing
2898 * else has to be done for private mappings here
2900 if (!vma || vma->vm_flags & VM_MAYSHARE)
2901 region_add(&inode->i_mapping->private_list, from, to);
2905 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2907 struct hstate *h = hstate_inode(inode);
2908 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2910 spin_lock(&inode->i_lock);
2911 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2912 spin_unlock(&inode->i_lock);
2914 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2915 hugetlb_acct_memory(h, -(chg - freed));
2918 #ifdef CONFIG_MEMORY_FAILURE
2920 /* Should be called in hugetlb_lock */
2921 static int is_hugepage_on_freelist(struct page *hpage)
2925 struct hstate *h = page_hstate(hpage);
2926 int nid = page_to_nid(hpage);
2928 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
2935 * This function is called from memory failure code.
2936 * Assume the caller holds page lock of the head page.
2938 int dequeue_hwpoisoned_huge_page(struct page *hpage)
2940 struct hstate *h = page_hstate(hpage);
2941 int nid = page_to_nid(hpage);
2944 spin_lock(&hugetlb_lock);
2945 if (is_hugepage_on_freelist(hpage)) {
2946 list_del(&hpage->lru);
2947 set_page_refcounted(hpage);
2948 h->free_huge_pages--;
2949 h->free_huge_pages_node[nid]--;
2952 spin_unlock(&hugetlb_lock);