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>
23 #include <asm/pgtable.h>
26 #include <linux/hugetlb.h>
27 #include <linux/node.h>
30 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
31 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
32 unsigned long hugepages_treat_as_movable;
34 static int max_hstate;
35 unsigned int default_hstate_idx;
36 struct hstate hstates[HUGE_MAX_HSTATE];
38 __initdata LIST_HEAD(huge_boot_pages);
40 /* for command line parsing */
41 static struct hstate * __initdata parsed_hstate;
42 static unsigned long __initdata default_hstate_max_huge_pages;
43 static unsigned long __initdata default_hstate_size;
45 #define for_each_hstate(h) \
46 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
49 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
51 static DEFINE_SPINLOCK(hugetlb_lock);
54 * Region tracking -- allows tracking of reservations and instantiated pages
55 * across the pages in a mapping.
57 * The region data structures are protected by a combination of the mmap_sem
58 * and the hugetlb_instantion_mutex. To access or modify a region the caller
59 * must either hold the mmap_sem for write, or the mmap_sem for read and
60 * the hugetlb_instantiation mutex:
62 * down_write(&mm->mmap_sem);
64 * down_read(&mm->mmap_sem);
65 * mutex_lock(&hugetlb_instantiation_mutex);
68 struct list_head link;
73 static long region_add(struct list_head *head, long f, long t)
75 struct file_region *rg, *nrg, *trg;
77 /* Locate the region we are either in or before. */
78 list_for_each_entry(rg, head, link)
82 /* Round our left edge to the current segment if it encloses us. */
86 /* Check for and consume any regions we now overlap with. */
88 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
89 if (&rg->link == head)
94 /* If this area reaches higher then extend our area to
95 * include it completely. If this is not the first area
96 * which we intend to reuse, free it. */
109 static long region_chg(struct list_head *head, long f, long t)
111 struct file_region *rg, *nrg;
114 /* Locate the region we are before or in. */
115 list_for_each_entry(rg, head, link)
119 /* If we are below the current region then a new region is required.
120 * Subtle, allocate a new region at the position but make it zero
121 * size such that we can guarantee to record the reservation. */
122 if (&rg->link == head || t < rg->from) {
123 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
128 INIT_LIST_HEAD(&nrg->link);
129 list_add(&nrg->link, rg->link.prev);
134 /* Round our left edge to the current segment if it encloses us. */
139 /* Check for and consume any regions we now overlap with. */
140 list_for_each_entry(rg, rg->link.prev, link) {
141 if (&rg->link == head)
146 /* We overlap with this area, if it extends futher than
147 * us then we must extend ourselves. Account for its
148 * existing reservation. */
153 chg -= rg->to - rg->from;
158 static long region_truncate(struct list_head *head, long end)
160 struct file_region *rg, *trg;
163 /* Locate the region we are either in or before. */
164 list_for_each_entry(rg, head, link)
167 if (&rg->link == head)
170 /* If we are in the middle of a region then adjust it. */
171 if (end > rg->from) {
174 rg = list_entry(rg->link.next, typeof(*rg), link);
177 /* Drop any remaining regions. */
178 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
179 if (&rg->link == head)
181 chg += rg->to - rg->from;
188 static long region_count(struct list_head *head, long f, long t)
190 struct file_region *rg;
193 /* Locate each segment we overlap with, and count that overlap. */
194 list_for_each_entry(rg, head, link) {
203 seg_from = max(rg->from, f);
204 seg_to = min(rg->to, t);
206 chg += seg_to - seg_from;
213 * Convert the address within this vma to the page offset within
214 * the mapping, in pagecache page units; huge pages here.
216 static pgoff_t vma_hugecache_offset(struct hstate *h,
217 struct vm_area_struct *vma, unsigned long address)
219 return ((address - vma->vm_start) >> huge_page_shift(h)) +
220 (vma->vm_pgoff >> huge_page_order(h));
224 * Return the size of the pages allocated when backing a VMA. In the majority
225 * cases this will be same size as used by the page table entries.
227 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
229 struct hstate *hstate;
231 if (!is_vm_hugetlb_page(vma))
234 hstate = hstate_vma(vma);
236 return 1UL << (hstate->order + PAGE_SHIFT);
238 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
241 * Return the page size being used by the MMU to back a VMA. In the majority
242 * of cases, the page size used by the kernel matches the MMU size. On
243 * architectures where it differs, an architecture-specific version of this
244 * function is required.
246 #ifndef vma_mmu_pagesize
247 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
249 return vma_kernel_pagesize(vma);
254 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
255 * bits of the reservation map pointer, which are always clear due to
258 #define HPAGE_RESV_OWNER (1UL << 0)
259 #define HPAGE_RESV_UNMAPPED (1UL << 1)
260 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
263 * These helpers are used to track how many pages are reserved for
264 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
265 * is guaranteed to have their future faults succeed.
267 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
268 * the reserve counters are updated with the hugetlb_lock held. It is safe
269 * to reset the VMA at fork() time as it is not in use yet and there is no
270 * chance of the global counters getting corrupted as a result of the values.
272 * The private mapping reservation is represented in a subtly different
273 * manner to a shared mapping. A shared mapping has a region map associated
274 * with the underlying file, this region map represents the backing file
275 * pages which have ever had a reservation assigned which this persists even
276 * after the page is instantiated. A private mapping has a region map
277 * associated with the original mmap which is attached to all VMAs which
278 * reference it, this region map represents those offsets which have consumed
279 * reservation ie. where pages have been instantiated.
281 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
283 return (unsigned long)vma->vm_private_data;
286 static void set_vma_private_data(struct vm_area_struct *vma,
289 vma->vm_private_data = (void *)value;
294 struct list_head regions;
297 static struct resv_map *resv_map_alloc(void)
299 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
303 kref_init(&resv_map->refs);
304 INIT_LIST_HEAD(&resv_map->regions);
309 static void resv_map_release(struct kref *ref)
311 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
313 /* Clear out any active regions before we release the map. */
314 region_truncate(&resv_map->regions, 0);
318 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
320 VM_BUG_ON(!is_vm_hugetlb_page(vma));
321 if (!(vma->vm_flags & VM_MAYSHARE))
322 return (struct resv_map *)(get_vma_private_data(vma) &
327 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
329 VM_BUG_ON(!is_vm_hugetlb_page(vma));
330 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
332 set_vma_private_data(vma, (get_vma_private_data(vma) &
333 HPAGE_RESV_MASK) | (unsigned long)map);
336 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
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) | flags);
344 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
346 VM_BUG_ON(!is_vm_hugetlb_page(vma));
348 return (get_vma_private_data(vma) & flag) != 0;
351 /* Decrement the reserved pages in the hugepage pool by one */
352 static void decrement_hugepage_resv_vma(struct hstate *h,
353 struct vm_area_struct *vma)
355 if (vma->vm_flags & VM_NORESERVE)
358 if (vma->vm_flags & VM_MAYSHARE) {
359 /* Shared mappings always use reserves */
360 h->resv_huge_pages--;
361 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
363 * Only the process that called mmap() has reserves for
366 h->resv_huge_pages--;
370 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
371 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
373 VM_BUG_ON(!is_vm_hugetlb_page(vma));
374 if (!(vma->vm_flags & VM_MAYSHARE))
375 vma->vm_private_data = (void *)0;
378 /* Returns true if the VMA has associated reserve pages */
379 static int vma_has_reserves(struct vm_area_struct *vma)
381 if (vma->vm_flags & VM_MAYSHARE)
383 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
388 static void clear_gigantic_page(struct page *page,
389 unsigned long addr, unsigned long sz)
392 struct page *p = page;
395 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
397 clear_user_highpage(p, addr + i * PAGE_SIZE);
400 static void clear_huge_page(struct page *page,
401 unsigned long addr, unsigned long sz)
405 if (unlikely(sz/PAGE_SIZE > MAX_ORDER_NR_PAGES)) {
406 clear_gigantic_page(page, addr, sz);
411 for (i = 0; i < sz/PAGE_SIZE; i++) {
413 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
417 static void copy_gigantic_page(struct page *dst, struct page *src,
418 unsigned long addr, struct vm_area_struct *vma)
421 struct hstate *h = hstate_vma(vma);
422 struct page *dst_base = dst;
423 struct page *src_base = src;
425 for (i = 0; i < pages_per_huge_page(h); ) {
427 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
430 dst = mem_map_next(dst, dst_base, i);
431 src = mem_map_next(src, src_base, i);
434 static void copy_huge_page(struct page *dst, struct page *src,
435 unsigned long addr, struct vm_area_struct *vma)
438 struct hstate *h = hstate_vma(vma);
440 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
441 copy_gigantic_page(dst, src, addr, vma);
446 for (i = 0; i < pages_per_huge_page(h); i++) {
448 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
452 static void enqueue_huge_page(struct hstate *h, struct page *page)
454 int nid = page_to_nid(page);
455 list_add(&page->lru, &h->hugepage_freelists[nid]);
456 h->free_huge_pages++;
457 h->free_huge_pages_node[nid]++;
460 static struct page *dequeue_huge_page_vma(struct hstate *h,
461 struct vm_area_struct *vma,
462 unsigned long address, int avoid_reserve)
465 struct page *page = NULL;
466 struct mempolicy *mpol;
467 nodemask_t *nodemask;
468 struct zonelist *zonelist;
473 zonelist = huge_zonelist(vma, address,
474 htlb_alloc_mask, &mpol, &nodemask);
476 * A child process with MAP_PRIVATE mappings created by their parent
477 * have no page reserves. This check ensures that reservations are
478 * not "stolen". The child may still get SIGKILLed
480 if (!vma_has_reserves(vma) &&
481 h->free_huge_pages - h->resv_huge_pages == 0)
484 /* If reserves cannot be used, ensure enough pages are in the pool */
485 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
488 for_each_zone_zonelist_nodemask(zone, z, zonelist,
489 MAX_NR_ZONES - 1, nodemask) {
490 nid = zone_to_nid(zone);
491 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
492 !list_empty(&h->hugepage_freelists[nid])) {
493 page = list_entry(h->hugepage_freelists[nid].next,
495 list_del(&page->lru);
496 h->free_huge_pages--;
497 h->free_huge_pages_node[nid]--;
500 decrement_hugepage_resv_vma(h, vma);
511 static void update_and_free_page(struct hstate *h, struct page *page)
515 VM_BUG_ON(h->order >= MAX_ORDER);
518 h->nr_huge_pages_node[page_to_nid(page)]--;
519 for (i = 0; i < pages_per_huge_page(h); i++) {
520 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
521 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
522 1 << PG_private | 1<< PG_writeback);
524 set_compound_page_dtor(page, NULL);
525 set_page_refcounted(page);
526 arch_release_hugepage(page);
527 __free_pages(page, huge_page_order(h));
530 struct hstate *size_to_hstate(unsigned long size)
535 if (huge_page_size(h) == size)
541 static void free_huge_page(struct page *page)
544 * Can't pass hstate in here because it is called from the
545 * compound page destructor.
547 struct hstate *h = page_hstate(page);
548 int nid = page_to_nid(page);
549 struct address_space *mapping;
551 mapping = (struct address_space *) page_private(page);
552 set_page_private(page, 0);
553 page->mapping = NULL;
554 BUG_ON(page_count(page));
555 INIT_LIST_HEAD(&page->lru);
557 spin_lock(&hugetlb_lock);
558 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
559 update_and_free_page(h, page);
560 h->surplus_huge_pages--;
561 h->surplus_huge_pages_node[nid]--;
563 enqueue_huge_page(h, page);
565 spin_unlock(&hugetlb_lock);
567 hugetlb_put_quota(mapping, 1);
570 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
572 set_compound_page_dtor(page, free_huge_page);
573 spin_lock(&hugetlb_lock);
575 h->nr_huge_pages_node[nid]++;
576 spin_unlock(&hugetlb_lock);
577 put_page(page); /* free it into the hugepage allocator */
580 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
583 int nr_pages = 1 << order;
584 struct page *p = page + 1;
586 /* we rely on prep_new_huge_page to set the destructor */
587 set_compound_order(page, order);
589 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
591 p->first_page = page;
595 int PageHuge(struct page *page)
597 compound_page_dtor *dtor;
599 if (!PageCompound(page))
602 page = compound_head(page);
603 dtor = get_compound_page_dtor(page);
605 return dtor == free_huge_page;
608 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
612 if (h->order >= MAX_ORDER)
615 page = alloc_pages_exact_node(nid,
616 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
617 __GFP_REPEAT|__GFP_NOWARN,
620 if (arch_prepare_hugepage(page)) {
621 __free_pages(page, huge_page_order(h));
624 prep_new_huge_page(h, page, nid);
631 * common helper functions for hstate_next_node_to_{alloc|free}.
632 * We may have allocated or freed a huge page based on a different
633 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
634 * be outside of *nodes_allowed. Ensure that we use an allowed
635 * node for alloc or free.
637 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
639 nid = next_node(nid, *nodes_allowed);
640 if (nid == MAX_NUMNODES)
641 nid = first_node(*nodes_allowed);
642 VM_BUG_ON(nid >= MAX_NUMNODES);
647 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
649 if (!node_isset(nid, *nodes_allowed))
650 nid = next_node_allowed(nid, nodes_allowed);
655 * returns the previously saved node ["this node"] from which to
656 * allocate a persistent huge page for the pool and advance the
657 * next node from which to allocate, handling wrap at end of node
660 static int hstate_next_node_to_alloc(struct hstate *h,
661 nodemask_t *nodes_allowed)
665 VM_BUG_ON(!nodes_allowed);
667 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
668 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
673 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
680 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
681 next_nid = start_nid;
684 page = alloc_fresh_huge_page_node(h, next_nid);
689 next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
690 } while (next_nid != start_nid);
693 count_vm_event(HTLB_BUDDY_PGALLOC);
695 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
701 * helper for free_pool_huge_page() - return the previously saved
702 * node ["this node"] from which to free a huge page. Advance the
703 * next node id whether or not we find a free huge page to free so
704 * that the next attempt to free addresses the next node.
706 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
710 VM_BUG_ON(!nodes_allowed);
712 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
713 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
719 * Free huge page from pool from next node to free.
720 * Attempt to keep persistent huge pages more or less
721 * balanced over allowed nodes.
722 * Called with hugetlb_lock locked.
724 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
731 start_nid = hstate_next_node_to_free(h, nodes_allowed);
732 next_nid = start_nid;
736 * If we're returning unused surplus pages, only examine
737 * nodes with surplus pages.
739 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
740 !list_empty(&h->hugepage_freelists[next_nid])) {
742 list_entry(h->hugepage_freelists[next_nid].next,
744 list_del(&page->lru);
745 h->free_huge_pages--;
746 h->free_huge_pages_node[next_nid]--;
748 h->surplus_huge_pages--;
749 h->surplus_huge_pages_node[next_nid]--;
751 update_and_free_page(h, page);
755 next_nid = hstate_next_node_to_free(h, nodes_allowed);
756 } while (next_nid != start_nid);
761 static struct page *alloc_buddy_huge_page(struct hstate *h,
762 struct vm_area_struct *vma, unsigned long address)
767 if (h->order >= MAX_ORDER)
771 * Assume we will successfully allocate the surplus page to
772 * prevent racing processes from causing the surplus to exceed
775 * This however introduces a different race, where a process B
776 * tries to grow the static hugepage pool while alloc_pages() is
777 * called by process A. B will only examine the per-node
778 * counters in determining if surplus huge pages can be
779 * converted to normal huge pages in adjust_pool_surplus(). A
780 * won't be able to increment the per-node counter, until the
781 * lock is dropped by B, but B doesn't drop hugetlb_lock until
782 * no more huge pages can be converted from surplus to normal
783 * state (and doesn't try to convert again). Thus, we have a
784 * case where a surplus huge page exists, the pool is grown, and
785 * the surplus huge page still exists after, even though it
786 * should just have been converted to a normal huge page. This
787 * does not leak memory, though, as the hugepage will be freed
788 * once it is out of use. It also does not allow the counters to
789 * go out of whack in adjust_pool_surplus() as we don't modify
790 * the node values until we've gotten the hugepage and only the
791 * per-node value is checked there.
793 spin_lock(&hugetlb_lock);
794 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
795 spin_unlock(&hugetlb_lock);
799 h->surplus_huge_pages++;
801 spin_unlock(&hugetlb_lock);
803 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
804 __GFP_REPEAT|__GFP_NOWARN,
807 if (page && arch_prepare_hugepage(page)) {
808 __free_pages(page, huge_page_order(h));
812 spin_lock(&hugetlb_lock);
815 * This page is now managed by the hugetlb allocator and has
816 * no users -- drop the buddy allocator's reference.
818 put_page_testzero(page);
819 VM_BUG_ON(page_count(page));
820 nid = page_to_nid(page);
821 set_compound_page_dtor(page, free_huge_page);
823 * We incremented the global counters already
825 h->nr_huge_pages_node[nid]++;
826 h->surplus_huge_pages_node[nid]++;
827 __count_vm_event(HTLB_BUDDY_PGALLOC);
830 h->surplus_huge_pages--;
831 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
833 spin_unlock(&hugetlb_lock);
839 * Increase the hugetlb pool such that it can accomodate a reservation
842 static int gather_surplus_pages(struct hstate *h, int delta)
844 struct list_head surplus_list;
845 struct page *page, *tmp;
847 int needed, allocated;
849 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
851 h->resv_huge_pages += delta;
856 INIT_LIST_HEAD(&surplus_list);
860 spin_unlock(&hugetlb_lock);
861 for (i = 0; i < needed; i++) {
862 page = alloc_buddy_huge_page(h, NULL, 0);
865 * We were not able to allocate enough pages to
866 * satisfy the entire reservation so we free what
867 * we've allocated so far.
869 spin_lock(&hugetlb_lock);
874 list_add(&page->lru, &surplus_list);
879 * After retaking hugetlb_lock, we need to recalculate 'needed'
880 * because either resv_huge_pages or free_huge_pages may have changed.
882 spin_lock(&hugetlb_lock);
883 needed = (h->resv_huge_pages + delta) -
884 (h->free_huge_pages + allocated);
889 * The surplus_list now contains _at_least_ the number of extra pages
890 * needed to accomodate the reservation. Add the appropriate number
891 * of pages to the hugetlb pool and free the extras back to the buddy
892 * allocator. Commit the entire reservation here to prevent another
893 * process from stealing the pages as they are added to the pool but
894 * before they are reserved.
897 h->resv_huge_pages += delta;
900 /* Free the needed pages to the hugetlb pool */
901 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
904 list_del(&page->lru);
905 enqueue_huge_page(h, page);
908 /* Free unnecessary surplus pages to the buddy allocator */
909 if (!list_empty(&surplus_list)) {
910 spin_unlock(&hugetlb_lock);
911 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
912 list_del(&page->lru);
914 * The page has a reference count of zero already, so
915 * call free_huge_page directly instead of using
916 * put_page. This must be done with hugetlb_lock
917 * unlocked which is safe because free_huge_page takes
918 * hugetlb_lock before deciding how to free the page.
920 free_huge_page(page);
922 spin_lock(&hugetlb_lock);
929 * When releasing a hugetlb pool reservation, any surplus pages that were
930 * allocated to satisfy the reservation must be explicitly freed if they were
932 * Called with hugetlb_lock held.
934 static void return_unused_surplus_pages(struct hstate *h,
935 unsigned long unused_resv_pages)
937 unsigned long nr_pages;
939 /* Uncommit the reservation */
940 h->resv_huge_pages -= unused_resv_pages;
942 /* Cannot return gigantic pages currently */
943 if (h->order >= MAX_ORDER)
946 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
949 * We want to release as many surplus pages as possible, spread
950 * evenly across all nodes with memory. Iterate across these nodes
951 * until we can no longer free unreserved surplus pages. This occurs
952 * when the nodes with surplus pages have no free pages.
953 * free_pool_huge_page() will balance the the freed pages across the
954 * on-line nodes with memory and will handle the hstate accounting.
957 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
963 * Determine if the huge page at addr within the vma has an associated
964 * reservation. Where it does not we will need to logically increase
965 * reservation and actually increase quota before an allocation can occur.
966 * Where any new reservation would be required the reservation change is
967 * prepared, but not committed. Once the page has been quota'd allocated
968 * an instantiated the change should be committed via vma_commit_reservation.
969 * No action is required on failure.
971 static long vma_needs_reservation(struct hstate *h,
972 struct vm_area_struct *vma, unsigned long addr)
974 struct address_space *mapping = vma->vm_file->f_mapping;
975 struct inode *inode = mapping->host;
977 if (vma->vm_flags & VM_MAYSHARE) {
978 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
979 return region_chg(&inode->i_mapping->private_list,
982 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
987 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
988 struct resv_map *reservations = vma_resv_map(vma);
990 err = region_chg(&reservations->regions, idx, idx + 1);
996 static void vma_commit_reservation(struct hstate *h,
997 struct vm_area_struct *vma, unsigned long addr)
999 struct address_space *mapping = vma->vm_file->f_mapping;
1000 struct inode *inode = mapping->host;
1002 if (vma->vm_flags & VM_MAYSHARE) {
1003 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1004 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1006 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1007 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1008 struct resv_map *reservations = vma_resv_map(vma);
1010 /* Mark this page used in the map. */
1011 region_add(&reservations->regions, idx, idx + 1);
1015 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1016 unsigned long addr, int avoid_reserve)
1018 struct hstate *h = hstate_vma(vma);
1020 struct address_space *mapping = vma->vm_file->f_mapping;
1021 struct inode *inode = mapping->host;
1025 * Processes that did not create the mapping will have no reserves and
1026 * will not have accounted against quota. Check that the quota can be
1027 * made before satisfying the allocation
1028 * MAP_NORESERVE mappings may also need pages and quota allocated
1029 * if no reserve mapping overlaps.
1031 chg = vma_needs_reservation(h, vma, addr);
1033 return ERR_PTR(-VM_FAULT_OOM);
1035 if (hugetlb_get_quota(inode->i_mapping, chg))
1036 return ERR_PTR(-VM_FAULT_SIGBUS);
1038 spin_lock(&hugetlb_lock);
1039 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1040 spin_unlock(&hugetlb_lock);
1043 page = alloc_buddy_huge_page(h, vma, addr);
1045 hugetlb_put_quota(inode->i_mapping, chg);
1046 return ERR_PTR(-VM_FAULT_SIGBUS);
1050 set_page_refcounted(page);
1051 set_page_private(page, (unsigned long) mapping);
1053 vma_commit_reservation(h, vma, addr);
1058 int __weak alloc_bootmem_huge_page(struct hstate *h)
1060 struct huge_bootmem_page *m;
1061 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1066 addr = __alloc_bootmem_node_nopanic(
1067 NODE_DATA(hstate_next_node_to_alloc(h,
1068 &node_states[N_HIGH_MEMORY])),
1069 huge_page_size(h), huge_page_size(h), 0);
1073 * Use the beginning of the huge page to store the
1074 * huge_bootmem_page struct (until gather_bootmem
1075 * puts them into the mem_map).
1085 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1086 /* Put them into a private list first because mem_map is not up yet */
1087 list_add(&m->list, &huge_boot_pages);
1092 static void prep_compound_huge_page(struct page *page, int order)
1094 if (unlikely(order > (MAX_ORDER - 1)))
1095 prep_compound_gigantic_page(page, order);
1097 prep_compound_page(page, order);
1100 /* Put bootmem huge pages into the standard lists after mem_map is up */
1101 static void __init gather_bootmem_prealloc(void)
1103 struct huge_bootmem_page *m;
1105 list_for_each_entry(m, &huge_boot_pages, list) {
1106 struct page *page = virt_to_page(m);
1107 struct hstate *h = m->hstate;
1108 __ClearPageReserved(page);
1109 WARN_ON(page_count(page) != 1);
1110 prep_compound_huge_page(page, h->order);
1111 prep_new_huge_page(h, page, page_to_nid(page));
1113 * If we had gigantic hugepages allocated at boot time, we need
1114 * to restore the 'stolen' pages to totalram_pages in order to
1115 * fix confusing memory reports from free(1) and another
1116 * side-effects, like CommitLimit going negative.
1118 if (h->order > (MAX_ORDER - 1))
1119 totalram_pages += 1 << h->order;
1123 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1127 for (i = 0; i < h->max_huge_pages; ++i) {
1128 if (h->order >= MAX_ORDER) {
1129 if (!alloc_bootmem_huge_page(h))
1131 } else if (!alloc_fresh_huge_page(h,
1132 &node_states[N_HIGH_MEMORY]))
1135 h->max_huge_pages = i;
1138 static void __init hugetlb_init_hstates(void)
1142 for_each_hstate(h) {
1143 /* oversize hugepages were init'ed in early boot */
1144 if (h->order < MAX_ORDER)
1145 hugetlb_hstate_alloc_pages(h);
1149 static char * __init memfmt(char *buf, unsigned long n)
1151 if (n >= (1UL << 30))
1152 sprintf(buf, "%lu GB", n >> 30);
1153 else if (n >= (1UL << 20))
1154 sprintf(buf, "%lu MB", n >> 20);
1156 sprintf(buf, "%lu KB", n >> 10);
1160 static void __init report_hugepages(void)
1164 for_each_hstate(h) {
1166 printk(KERN_INFO "HugeTLB registered %s page size, "
1167 "pre-allocated %ld pages\n",
1168 memfmt(buf, huge_page_size(h)),
1169 h->free_huge_pages);
1173 #ifdef CONFIG_HIGHMEM
1174 static void try_to_free_low(struct hstate *h, unsigned long count,
1175 nodemask_t *nodes_allowed)
1179 if (h->order >= MAX_ORDER)
1182 for_each_node_mask(i, *nodes_allowed) {
1183 struct page *page, *next;
1184 struct list_head *freel = &h->hugepage_freelists[i];
1185 list_for_each_entry_safe(page, next, freel, lru) {
1186 if (count >= h->nr_huge_pages)
1188 if (PageHighMem(page))
1190 list_del(&page->lru);
1191 update_and_free_page(h, page);
1192 h->free_huge_pages--;
1193 h->free_huge_pages_node[page_to_nid(page)]--;
1198 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1199 nodemask_t *nodes_allowed)
1205 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1206 * balanced by operating on them in a round-robin fashion.
1207 * Returns 1 if an adjustment was made.
1209 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1212 int start_nid, next_nid;
1215 VM_BUG_ON(delta != -1 && delta != 1);
1218 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1220 start_nid = hstate_next_node_to_free(h, nodes_allowed);
1221 next_nid = start_nid;
1227 * To shrink on this node, there must be a surplus page
1229 if (!h->surplus_huge_pages_node[nid]) {
1230 next_nid = hstate_next_node_to_alloc(h,
1237 * Surplus cannot exceed the total number of pages
1239 if (h->surplus_huge_pages_node[nid] >=
1240 h->nr_huge_pages_node[nid]) {
1241 next_nid = hstate_next_node_to_free(h,
1247 h->surplus_huge_pages += delta;
1248 h->surplus_huge_pages_node[nid] += delta;
1251 } while (next_nid != start_nid);
1256 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1257 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1258 nodemask_t *nodes_allowed)
1260 unsigned long min_count, ret;
1262 if (h->order >= MAX_ORDER)
1263 return h->max_huge_pages;
1266 * Increase the pool size
1267 * First take pages out of surplus state. Then make up the
1268 * remaining difference by allocating fresh huge pages.
1270 * We might race with alloc_buddy_huge_page() here and be unable
1271 * to convert a surplus huge page to a normal huge page. That is
1272 * not critical, though, it just means the overall size of the
1273 * pool might be one hugepage larger than it needs to be, but
1274 * within all the constraints specified by the sysctls.
1276 spin_lock(&hugetlb_lock);
1277 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1278 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1282 while (count > persistent_huge_pages(h)) {
1284 * If this allocation races such that we no longer need the
1285 * page, free_huge_page will handle it by freeing the page
1286 * and reducing the surplus.
1288 spin_unlock(&hugetlb_lock);
1289 ret = alloc_fresh_huge_page(h, nodes_allowed);
1290 spin_lock(&hugetlb_lock);
1294 /* Bail for signals. Probably ctrl-c from user */
1295 if (signal_pending(current))
1300 * Decrease the pool size
1301 * First return free pages to the buddy allocator (being careful
1302 * to keep enough around to satisfy reservations). Then place
1303 * pages into surplus state as needed so the pool will shrink
1304 * to the desired size as pages become free.
1306 * By placing pages into the surplus state independent of the
1307 * overcommit value, we are allowing the surplus pool size to
1308 * exceed overcommit. There are few sane options here. Since
1309 * alloc_buddy_huge_page() is checking the global counter,
1310 * though, we'll note that we're not allowed to exceed surplus
1311 * and won't grow the pool anywhere else. Not until one of the
1312 * sysctls are changed, or the surplus pages go out of use.
1314 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1315 min_count = max(count, min_count);
1316 try_to_free_low(h, min_count, nodes_allowed);
1317 while (min_count < persistent_huge_pages(h)) {
1318 if (!free_pool_huge_page(h, nodes_allowed, 0))
1321 while (count < persistent_huge_pages(h)) {
1322 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1326 ret = persistent_huge_pages(h);
1327 spin_unlock(&hugetlb_lock);
1331 #define HSTATE_ATTR_RO(_name) \
1332 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1334 #define HSTATE_ATTR(_name) \
1335 static struct kobj_attribute _name##_attr = \
1336 __ATTR(_name, 0644, _name##_show, _name##_store)
1338 static struct kobject *hugepages_kobj;
1339 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1341 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1343 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1347 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1348 if (hstate_kobjs[i] == kobj) {
1350 *nidp = NUMA_NO_NODE;
1354 return kobj_to_node_hstate(kobj, nidp);
1357 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1358 struct kobj_attribute *attr, char *buf)
1361 unsigned long nr_huge_pages;
1364 h = kobj_to_hstate(kobj, &nid);
1365 if (nid == NUMA_NO_NODE)
1366 nr_huge_pages = h->nr_huge_pages;
1368 nr_huge_pages = h->nr_huge_pages_node[nid];
1370 return sprintf(buf, "%lu\n", nr_huge_pages);
1372 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1373 struct kobject *kobj, struct kobj_attribute *attr,
1374 const char *buf, size_t len)
1378 unsigned long count;
1380 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1382 err = strict_strtoul(buf, 10, &count);
1386 h = kobj_to_hstate(kobj, &nid);
1387 if (nid == NUMA_NO_NODE) {
1389 * global hstate attribute
1391 if (!(obey_mempolicy &&
1392 init_nodemask_of_mempolicy(nodes_allowed))) {
1393 NODEMASK_FREE(nodes_allowed);
1394 nodes_allowed = &node_states[N_HIGH_MEMORY];
1396 } else if (nodes_allowed) {
1398 * per node hstate attribute: adjust count to global,
1399 * but restrict alloc/free to the specified node.
1401 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1402 init_nodemask_of_node(nodes_allowed, nid);
1404 nodes_allowed = &node_states[N_HIGH_MEMORY];
1406 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1408 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1409 NODEMASK_FREE(nodes_allowed);
1414 static ssize_t nr_hugepages_show(struct kobject *kobj,
1415 struct kobj_attribute *attr, char *buf)
1417 return nr_hugepages_show_common(kobj, attr, buf);
1420 static ssize_t nr_hugepages_store(struct kobject *kobj,
1421 struct kobj_attribute *attr, const char *buf, size_t len)
1423 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1425 HSTATE_ATTR(nr_hugepages);
1430 * hstate attribute for optionally mempolicy-based constraint on persistent
1431 * huge page alloc/free.
1433 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1434 struct kobj_attribute *attr, char *buf)
1436 return nr_hugepages_show_common(kobj, attr, buf);
1439 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1440 struct kobj_attribute *attr, const char *buf, size_t len)
1442 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1444 HSTATE_ATTR(nr_hugepages_mempolicy);
1448 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1449 struct kobj_attribute *attr, char *buf)
1451 struct hstate *h = kobj_to_hstate(kobj, NULL);
1452 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1454 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1455 struct kobj_attribute *attr, const char *buf, size_t count)
1458 unsigned long input;
1459 struct hstate *h = kobj_to_hstate(kobj, NULL);
1461 err = strict_strtoul(buf, 10, &input);
1465 spin_lock(&hugetlb_lock);
1466 h->nr_overcommit_huge_pages = input;
1467 spin_unlock(&hugetlb_lock);
1471 HSTATE_ATTR(nr_overcommit_hugepages);
1473 static ssize_t free_hugepages_show(struct kobject *kobj,
1474 struct kobj_attribute *attr, char *buf)
1477 unsigned long free_huge_pages;
1480 h = kobj_to_hstate(kobj, &nid);
1481 if (nid == NUMA_NO_NODE)
1482 free_huge_pages = h->free_huge_pages;
1484 free_huge_pages = h->free_huge_pages_node[nid];
1486 return sprintf(buf, "%lu\n", free_huge_pages);
1488 HSTATE_ATTR_RO(free_hugepages);
1490 static ssize_t resv_hugepages_show(struct kobject *kobj,
1491 struct kobj_attribute *attr, char *buf)
1493 struct hstate *h = kobj_to_hstate(kobj, NULL);
1494 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1496 HSTATE_ATTR_RO(resv_hugepages);
1498 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1499 struct kobj_attribute *attr, char *buf)
1502 unsigned long surplus_huge_pages;
1505 h = kobj_to_hstate(kobj, &nid);
1506 if (nid == NUMA_NO_NODE)
1507 surplus_huge_pages = h->surplus_huge_pages;
1509 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1511 return sprintf(buf, "%lu\n", surplus_huge_pages);
1513 HSTATE_ATTR_RO(surplus_hugepages);
1515 static struct attribute *hstate_attrs[] = {
1516 &nr_hugepages_attr.attr,
1517 &nr_overcommit_hugepages_attr.attr,
1518 &free_hugepages_attr.attr,
1519 &resv_hugepages_attr.attr,
1520 &surplus_hugepages_attr.attr,
1522 &nr_hugepages_mempolicy_attr.attr,
1527 static struct attribute_group hstate_attr_group = {
1528 .attrs = hstate_attrs,
1531 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1532 struct kobject **hstate_kobjs,
1533 struct attribute_group *hstate_attr_group)
1536 int hi = h - hstates;
1538 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1539 if (!hstate_kobjs[hi])
1542 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1544 kobject_put(hstate_kobjs[hi]);
1549 static void __init hugetlb_sysfs_init(void)
1554 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1555 if (!hugepages_kobj)
1558 for_each_hstate(h) {
1559 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1560 hstate_kobjs, &hstate_attr_group);
1562 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1570 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1571 * with node sysdevs in node_devices[] using a parallel array. The array
1572 * index of a node sysdev or _hstate == node id.
1573 * This is here to avoid any static dependency of the node sysdev driver, in
1574 * the base kernel, on the hugetlb module.
1576 struct node_hstate {
1577 struct kobject *hugepages_kobj;
1578 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1580 struct node_hstate node_hstates[MAX_NUMNODES];
1583 * A subset of global hstate attributes for node sysdevs
1585 static struct attribute *per_node_hstate_attrs[] = {
1586 &nr_hugepages_attr.attr,
1587 &free_hugepages_attr.attr,
1588 &surplus_hugepages_attr.attr,
1592 static struct attribute_group per_node_hstate_attr_group = {
1593 .attrs = per_node_hstate_attrs,
1597 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1598 * Returns node id via non-NULL nidp.
1600 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1604 for (nid = 0; nid < nr_node_ids; nid++) {
1605 struct node_hstate *nhs = &node_hstates[nid];
1607 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1608 if (nhs->hstate_kobjs[i] == kobj) {
1620 * Unregister hstate attributes from a single node sysdev.
1621 * No-op if no hstate attributes attached.
1623 void hugetlb_unregister_node(struct node *node)
1626 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1628 if (!nhs->hugepages_kobj)
1629 return; /* no hstate attributes */
1632 if (nhs->hstate_kobjs[h - hstates]) {
1633 kobject_put(nhs->hstate_kobjs[h - hstates]);
1634 nhs->hstate_kobjs[h - hstates] = NULL;
1637 kobject_put(nhs->hugepages_kobj);
1638 nhs->hugepages_kobj = NULL;
1642 * hugetlb module exit: unregister hstate attributes from node sysdevs
1645 static void hugetlb_unregister_all_nodes(void)
1650 * disable node sysdev registrations.
1652 register_hugetlbfs_with_node(NULL, NULL);
1655 * remove hstate attributes from any nodes that have them.
1657 for (nid = 0; nid < nr_node_ids; nid++)
1658 hugetlb_unregister_node(&node_devices[nid]);
1662 * Register hstate attributes for a single node sysdev.
1663 * No-op if attributes already registered.
1665 void hugetlb_register_node(struct node *node)
1668 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1671 if (nhs->hugepages_kobj)
1672 return; /* already allocated */
1674 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1675 &node->sysdev.kobj);
1676 if (!nhs->hugepages_kobj)
1679 for_each_hstate(h) {
1680 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1682 &per_node_hstate_attr_group);
1684 printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
1686 h->name, node->sysdev.id);
1687 hugetlb_unregister_node(node);
1694 * hugetlb init time: register hstate attributes for all registered node
1695 * sysdevs of nodes that have memory. All on-line nodes should have
1696 * registered their associated sysdev by this time.
1698 static void hugetlb_register_all_nodes(void)
1702 for_each_node_state(nid, N_HIGH_MEMORY) {
1703 struct node *node = &node_devices[nid];
1704 if (node->sysdev.id == nid)
1705 hugetlb_register_node(node);
1709 * Let the node sysdev driver know we're here so it can
1710 * [un]register hstate attributes on node hotplug.
1712 register_hugetlbfs_with_node(hugetlb_register_node,
1713 hugetlb_unregister_node);
1715 #else /* !CONFIG_NUMA */
1717 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1725 static void hugetlb_unregister_all_nodes(void) { }
1727 static void hugetlb_register_all_nodes(void) { }
1731 static void __exit hugetlb_exit(void)
1735 hugetlb_unregister_all_nodes();
1737 for_each_hstate(h) {
1738 kobject_put(hstate_kobjs[h - hstates]);
1741 kobject_put(hugepages_kobj);
1743 module_exit(hugetlb_exit);
1745 static int __init hugetlb_init(void)
1747 /* Some platform decide whether they support huge pages at boot
1748 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1749 * there is no such support
1751 if (HPAGE_SHIFT == 0)
1754 if (!size_to_hstate(default_hstate_size)) {
1755 default_hstate_size = HPAGE_SIZE;
1756 if (!size_to_hstate(default_hstate_size))
1757 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1759 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1760 if (default_hstate_max_huge_pages)
1761 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1763 hugetlb_init_hstates();
1765 gather_bootmem_prealloc();
1769 hugetlb_sysfs_init();
1771 hugetlb_register_all_nodes();
1775 module_init(hugetlb_init);
1777 /* Should be called on processing a hugepagesz=... option */
1778 void __init hugetlb_add_hstate(unsigned order)
1783 if (size_to_hstate(PAGE_SIZE << order)) {
1784 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1787 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1789 h = &hstates[max_hstate++];
1791 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1792 h->nr_huge_pages = 0;
1793 h->free_huge_pages = 0;
1794 for (i = 0; i < MAX_NUMNODES; ++i)
1795 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1796 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
1797 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1798 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1799 huge_page_size(h)/1024);
1804 static int __init hugetlb_nrpages_setup(char *s)
1807 static unsigned long *last_mhp;
1810 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1811 * so this hugepages= parameter goes to the "default hstate".
1814 mhp = &default_hstate_max_huge_pages;
1816 mhp = &parsed_hstate->max_huge_pages;
1818 if (mhp == last_mhp) {
1819 printk(KERN_WARNING "hugepages= specified twice without "
1820 "interleaving hugepagesz=, ignoring\n");
1824 if (sscanf(s, "%lu", mhp) <= 0)
1828 * Global state is always initialized later in hugetlb_init.
1829 * But we need to allocate >= MAX_ORDER hstates here early to still
1830 * use the bootmem allocator.
1832 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1833 hugetlb_hstate_alloc_pages(parsed_hstate);
1839 __setup("hugepages=", hugetlb_nrpages_setup);
1841 static int __init hugetlb_default_setup(char *s)
1843 default_hstate_size = memparse(s, &s);
1846 __setup("default_hugepagesz=", hugetlb_default_setup);
1848 static unsigned int cpuset_mems_nr(unsigned int *array)
1851 unsigned int nr = 0;
1853 for_each_node_mask(node, cpuset_current_mems_allowed)
1859 #ifdef CONFIG_SYSCTL
1860 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
1861 struct ctl_table *table, int write,
1862 void __user *buffer, size_t *length, loff_t *ppos)
1864 struct hstate *h = &default_hstate;
1868 tmp = h->max_huge_pages;
1871 table->maxlen = sizeof(unsigned long);
1872 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1875 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
1876 GFP_KERNEL | __GFP_NORETRY);
1877 if (!(obey_mempolicy &&
1878 init_nodemask_of_mempolicy(nodes_allowed))) {
1879 NODEMASK_FREE(nodes_allowed);
1880 nodes_allowed = &node_states[N_HIGH_MEMORY];
1882 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
1884 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1885 NODEMASK_FREE(nodes_allowed);
1891 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1892 void __user *buffer, size_t *length, loff_t *ppos)
1895 return hugetlb_sysctl_handler_common(false, table, write,
1896 buffer, length, ppos);
1900 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
1901 void __user *buffer, size_t *length, loff_t *ppos)
1903 return hugetlb_sysctl_handler_common(true, table, write,
1904 buffer, length, ppos);
1906 #endif /* CONFIG_NUMA */
1908 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1909 void __user *buffer,
1910 size_t *length, loff_t *ppos)
1912 proc_dointvec(table, write, buffer, length, ppos);
1913 if (hugepages_treat_as_movable)
1914 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1916 htlb_alloc_mask = GFP_HIGHUSER;
1920 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1921 void __user *buffer,
1922 size_t *length, loff_t *ppos)
1924 struct hstate *h = &default_hstate;
1928 tmp = h->nr_overcommit_huge_pages;
1931 table->maxlen = sizeof(unsigned long);
1932 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1935 spin_lock(&hugetlb_lock);
1936 h->nr_overcommit_huge_pages = tmp;
1937 spin_unlock(&hugetlb_lock);
1943 #endif /* CONFIG_SYSCTL */
1945 void hugetlb_report_meminfo(struct seq_file *m)
1947 struct hstate *h = &default_hstate;
1949 "HugePages_Total: %5lu\n"
1950 "HugePages_Free: %5lu\n"
1951 "HugePages_Rsvd: %5lu\n"
1952 "HugePages_Surp: %5lu\n"
1953 "Hugepagesize: %8lu kB\n",
1957 h->surplus_huge_pages,
1958 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1961 int hugetlb_report_node_meminfo(int nid, char *buf)
1963 struct hstate *h = &default_hstate;
1965 "Node %d HugePages_Total: %5u\n"
1966 "Node %d HugePages_Free: %5u\n"
1967 "Node %d HugePages_Surp: %5u\n",
1968 nid, h->nr_huge_pages_node[nid],
1969 nid, h->free_huge_pages_node[nid],
1970 nid, h->surplus_huge_pages_node[nid]);
1973 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1974 unsigned long hugetlb_total_pages(void)
1976 struct hstate *h = &default_hstate;
1977 return h->nr_huge_pages * pages_per_huge_page(h);
1980 static int hugetlb_acct_memory(struct hstate *h, long delta)
1984 spin_lock(&hugetlb_lock);
1986 * When cpuset is configured, it breaks the strict hugetlb page
1987 * reservation as the accounting is done on a global variable. Such
1988 * reservation is completely rubbish in the presence of cpuset because
1989 * the reservation is not checked against page availability for the
1990 * current cpuset. Application can still potentially OOM'ed by kernel
1991 * with lack of free htlb page in cpuset that the task is in.
1992 * Attempt to enforce strict accounting with cpuset is almost
1993 * impossible (or too ugly) because cpuset is too fluid that
1994 * task or memory node can be dynamically moved between cpusets.
1996 * The change of semantics for shared hugetlb mapping with cpuset is
1997 * undesirable. However, in order to preserve some of the semantics,
1998 * we fall back to check against current free page availability as
1999 * a best attempt and hopefully to minimize the impact of changing
2000 * semantics that cpuset has.
2003 if (gather_surplus_pages(h, delta) < 0)
2006 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2007 return_unused_surplus_pages(h, delta);
2014 return_unused_surplus_pages(h, (unsigned long) -delta);
2017 spin_unlock(&hugetlb_lock);
2021 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2023 struct resv_map *reservations = vma_resv_map(vma);
2026 * This new VMA should share its siblings reservation map if present.
2027 * The VMA will only ever have a valid reservation map pointer where
2028 * it is being copied for another still existing VMA. As that VMA
2029 * has a reference to the reservation map it cannot dissappear until
2030 * after this open call completes. It is therefore safe to take a
2031 * new reference here without additional locking.
2034 kref_get(&reservations->refs);
2037 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2039 struct hstate *h = hstate_vma(vma);
2040 struct resv_map *reservations = vma_resv_map(vma);
2041 unsigned long reserve;
2042 unsigned long start;
2046 start = vma_hugecache_offset(h, vma, vma->vm_start);
2047 end = vma_hugecache_offset(h, vma, vma->vm_end);
2049 reserve = (end - start) -
2050 region_count(&reservations->regions, start, end);
2052 kref_put(&reservations->refs, resv_map_release);
2055 hugetlb_acct_memory(h, -reserve);
2056 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
2062 * We cannot handle pagefaults against hugetlb pages at all. They cause
2063 * handle_mm_fault() to try to instantiate regular-sized pages in the
2064 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2067 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2073 const struct vm_operations_struct hugetlb_vm_ops = {
2074 .fault = hugetlb_vm_op_fault,
2075 .open = hugetlb_vm_op_open,
2076 .close = hugetlb_vm_op_close,
2079 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2086 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
2088 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
2090 entry = pte_mkyoung(entry);
2091 entry = pte_mkhuge(entry);
2096 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2097 unsigned long address, pte_t *ptep)
2101 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2102 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
2103 update_mmu_cache(vma, address, ptep);
2108 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2109 struct vm_area_struct *vma)
2111 pte_t *src_pte, *dst_pte, entry;
2112 struct page *ptepage;
2115 struct hstate *h = hstate_vma(vma);
2116 unsigned long sz = huge_page_size(h);
2118 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2120 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2121 src_pte = huge_pte_offset(src, addr);
2124 dst_pte = huge_pte_alloc(dst, addr, sz);
2128 /* If the pagetables are shared don't copy or take references */
2129 if (dst_pte == src_pte)
2132 spin_lock(&dst->page_table_lock);
2133 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2134 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2136 huge_ptep_set_wrprotect(src, addr, src_pte);
2137 entry = huge_ptep_get(src_pte);
2138 ptepage = pte_page(entry);
2140 set_huge_pte_at(dst, addr, dst_pte, entry);
2142 spin_unlock(&src->page_table_lock);
2143 spin_unlock(&dst->page_table_lock);
2151 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2152 unsigned long end, struct page *ref_page)
2154 struct mm_struct *mm = vma->vm_mm;
2155 unsigned long address;
2160 struct hstate *h = hstate_vma(vma);
2161 unsigned long sz = huge_page_size(h);
2164 * A page gathering list, protected by per file i_mmap_lock. The
2165 * lock is used to avoid list corruption from multiple unmapping
2166 * of the same page since we are using page->lru.
2168 LIST_HEAD(page_list);
2170 WARN_ON(!is_vm_hugetlb_page(vma));
2171 BUG_ON(start & ~huge_page_mask(h));
2172 BUG_ON(end & ~huge_page_mask(h));
2174 mmu_notifier_invalidate_range_start(mm, start, end);
2175 spin_lock(&mm->page_table_lock);
2176 for (address = start; address < end; address += sz) {
2177 ptep = huge_pte_offset(mm, address);
2181 if (huge_pmd_unshare(mm, &address, ptep))
2185 * If a reference page is supplied, it is because a specific
2186 * page is being unmapped, not a range. Ensure the page we
2187 * are about to unmap is the actual page of interest.
2190 pte = huge_ptep_get(ptep);
2191 if (huge_pte_none(pte))
2193 page = pte_page(pte);
2194 if (page != ref_page)
2198 * Mark the VMA as having unmapped its page so that
2199 * future faults in this VMA will fail rather than
2200 * looking like data was lost
2202 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2205 pte = huge_ptep_get_and_clear(mm, address, ptep);
2206 if (huge_pte_none(pte))
2209 page = pte_page(pte);
2211 set_page_dirty(page);
2212 list_add(&page->lru, &page_list);
2214 spin_unlock(&mm->page_table_lock);
2215 flush_tlb_range(vma, start, end);
2216 mmu_notifier_invalidate_range_end(mm, start, end);
2217 list_for_each_entry_safe(page, tmp, &page_list, lru) {
2218 list_del(&page->lru);
2223 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2224 unsigned long end, struct page *ref_page)
2226 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2227 __unmap_hugepage_range(vma, start, end, ref_page);
2228 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2232 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2233 * mappping it owns the reserve page for. The intention is to unmap the page
2234 * from other VMAs and let the children be SIGKILLed if they are faulting the
2237 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2238 struct page *page, unsigned long address)
2240 struct hstate *h = hstate_vma(vma);
2241 struct vm_area_struct *iter_vma;
2242 struct address_space *mapping;
2243 struct prio_tree_iter iter;
2247 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2248 * from page cache lookup which is in HPAGE_SIZE units.
2250 address = address & huge_page_mask(h);
2251 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
2252 + (vma->vm_pgoff >> PAGE_SHIFT);
2253 mapping = (struct address_space *)page_private(page);
2256 * Take the mapping lock for the duration of the table walk. As
2257 * this mapping should be shared between all the VMAs,
2258 * __unmap_hugepage_range() is called as the lock is already held
2260 spin_lock(&mapping->i_mmap_lock);
2261 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
2262 /* Do not unmap the current VMA */
2263 if (iter_vma == vma)
2267 * Unmap the page from other VMAs without their own reserves.
2268 * They get marked to be SIGKILLed if they fault in these
2269 * areas. This is because a future no-page fault on this VMA
2270 * could insert a zeroed page instead of the data existing
2271 * from the time of fork. This would look like data corruption
2273 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2274 __unmap_hugepage_range(iter_vma,
2275 address, address + huge_page_size(h),
2278 spin_unlock(&mapping->i_mmap_lock);
2283 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2284 unsigned long address, pte_t *ptep, pte_t pte,
2285 struct page *pagecache_page)
2287 struct hstate *h = hstate_vma(vma);
2288 struct page *old_page, *new_page;
2290 int outside_reserve = 0;
2292 old_page = pte_page(pte);
2295 /* If no-one else is actually using this page, avoid the copy
2296 * and just make the page writable */
2297 avoidcopy = (page_count(old_page) == 1);
2299 set_huge_ptep_writable(vma, address, ptep);
2304 * If the process that created a MAP_PRIVATE mapping is about to
2305 * perform a COW due to a shared page count, attempt to satisfy
2306 * the allocation without using the existing reserves. The pagecache
2307 * page is used to determine if the reserve at this address was
2308 * consumed or not. If reserves were used, a partial faulted mapping
2309 * at the time of fork() could consume its reserves on COW instead
2310 * of the full address range.
2312 if (!(vma->vm_flags & VM_MAYSHARE) &&
2313 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2314 old_page != pagecache_page)
2315 outside_reserve = 1;
2317 page_cache_get(old_page);
2319 /* Drop page_table_lock as buddy allocator may be called */
2320 spin_unlock(&mm->page_table_lock);
2321 new_page = alloc_huge_page(vma, address, outside_reserve);
2323 if (IS_ERR(new_page)) {
2324 page_cache_release(old_page);
2327 * If a process owning a MAP_PRIVATE mapping fails to COW,
2328 * it is due to references held by a child and an insufficient
2329 * huge page pool. To guarantee the original mappers
2330 * reliability, unmap the page from child processes. The child
2331 * may get SIGKILLed if it later faults.
2333 if (outside_reserve) {
2334 BUG_ON(huge_pte_none(pte));
2335 if (unmap_ref_private(mm, vma, old_page, address)) {
2336 BUG_ON(page_count(old_page) != 1);
2337 BUG_ON(huge_pte_none(pte));
2338 spin_lock(&mm->page_table_lock);
2339 goto retry_avoidcopy;
2344 /* Caller expects lock to be held */
2345 spin_lock(&mm->page_table_lock);
2346 return -PTR_ERR(new_page);
2349 copy_huge_page(new_page, old_page, address, vma);
2350 __SetPageUptodate(new_page);
2353 * Retake the page_table_lock to check for racing updates
2354 * before the page tables are altered
2356 spin_lock(&mm->page_table_lock);
2357 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2358 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2360 huge_ptep_clear_flush(vma, address, ptep);
2361 set_huge_pte_at(mm, address, ptep,
2362 make_huge_pte(vma, new_page, 1));
2363 /* Make the old page be freed below */
2364 new_page = old_page;
2366 page_cache_release(new_page);
2367 page_cache_release(old_page);
2371 /* Return the pagecache page at a given address within a VMA */
2372 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2373 struct vm_area_struct *vma, unsigned long address)
2375 struct address_space *mapping;
2378 mapping = vma->vm_file->f_mapping;
2379 idx = vma_hugecache_offset(h, vma, address);
2381 return find_lock_page(mapping, idx);
2385 * Return whether there is a pagecache page to back given address within VMA.
2386 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2388 static bool hugetlbfs_pagecache_present(struct hstate *h,
2389 struct vm_area_struct *vma, unsigned long address)
2391 struct address_space *mapping;
2395 mapping = vma->vm_file->f_mapping;
2396 idx = vma_hugecache_offset(h, vma, address);
2398 page = find_get_page(mapping, idx);
2401 return page != NULL;
2404 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2405 unsigned long address, pte_t *ptep, unsigned int flags)
2407 struct hstate *h = hstate_vma(vma);
2408 int ret = VM_FAULT_SIGBUS;
2412 struct address_space *mapping;
2416 * Currently, we are forced to kill the process in the event the
2417 * original mapper has unmapped pages from the child due to a failed
2418 * COW. Warn that such a situation has occured as it may not be obvious
2420 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2422 "PID %d killed due to inadequate hugepage pool\n",
2427 mapping = vma->vm_file->f_mapping;
2428 idx = vma_hugecache_offset(h, vma, address);
2431 * Use page lock to guard against racing truncation
2432 * before we get page_table_lock.
2435 page = find_lock_page(mapping, idx);
2437 size = i_size_read(mapping->host) >> huge_page_shift(h);
2440 page = alloc_huge_page(vma, address, 0);
2442 ret = -PTR_ERR(page);
2445 clear_huge_page(page, address, huge_page_size(h));
2446 __SetPageUptodate(page);
2448 if (vma->vm_flags & VM_MAYSHARE) {
2450 struct inode *inode = mapping->host;
2452 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2460 spin_lock(&inode->i_lock);
2461 inode->i_blocks += blocks_per_huge_page(h);
2462 spin_unlock(&inode->i_lock);
2465 page->mapping = HUGETLB_POISON;
2470 * If we are going to COW a private mapping later, we examine the
2471 * pending reservations for this page now. This will ensure that
2472 * any allocations necessary to record that reservation occur outside
2475 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2476 if (vma_needs_reservation(h, vma, address) < 0) {
2478 goto backout_unlocked;
2481 spin_lock(&mm->page_table_lock);
2482 size = i_size_read(mapping->host) >> huge_page_shift(h);
2487 if (!huge_pte_none(huge_ptep_get(ptep)))
2490 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2491 && (vma->vm_flags & VM_SHARED)));
2492 set_huge_pte_at(mm, address, ptep, new_pte);
2494 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2495 /* Optimization, do the COW without a second fault */
2496 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2499 spin_unlock(&mm->page_table_lock);
2505 spin_unlock(&mm->page_table_lock);
2512 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2513 unsigned long address, unsigned int flags)
2518 struct page *pagecache_page = NULL;
2519 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2520 struct hstate *h = hstate_vma(vma);
2522 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2524 return VM_FAULT_OOM;
2527 * Serialize hugepage allocation and instantiation, so that we don't
2528 * get spurious allocation failures if two CPUs race to instantiate
2529 * the same page in the page cache.
2531 mutex_lock(&hugetlb_instantiation_mutex);
2532 entry = huge_ptep_get(ptep);
2533 if (huge_pte_none(entry)) {
2534 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2541 * If we are going to COW the mapping later, we examine the pending
2542 * reservations for this page now. This will ensure that any
2543 * allocations necessary to record that reservation occur outside the
2544 * spinlock. For private mappings, we also lookup the pagecache
2545 * page now as it is used to determine if a reservation has been
2548 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2549 if (vma_needs_reservation(h, vma, address) < 0) {
2554 if (!(vma->vm_flags & VM_MAYSHARE))
2555 pagecache_page = hugetlbfs_pagecache_page(h,
2559 spin_lock(&mm->page_table_lock);
2560 /* Check for a racing update before calling hugetlb_cow */
2561 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2562 goto out_page_table_lock;
2565 if (flags & FAULT_FLAG_WRITE) {
2566 if (!pte_write(entry)) {
2567 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2569 goto out_page_table_lock;
2571 entry = pte_mkdirty(entry);
2573 entry = pte_mkyoung(entry);
2574 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2575 flags & FAULT_FLAG_WRITE))
2576 update_mmu_cache(vma, address, ptep);
2578 out_page_table_lock:
2579 spin_unlock(&mm->page_table_lock);
2581 if (pagecache_page) {
2582 unlock_page(pagecache_page);
2583 put_page(pagecache_page);
2587 mutex_unlock(&hugetlb_instantiation_mutex);
2592 /* Can be overriden by architectures */
2593 __attribute__((weak)) struct page *
2594 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2595 pud_t *pud, int write)
2601 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2602 struct page **pages, struct vm_area_struct **vmas,
2603 unsigned long *position, int *length, int i,
2606 unsigned long pfn_offset;
2607 unsigned long vaddr = *position;
2608 int remainder = *length;
2609 struct hstate *h = hstate_vma(vma);
2611 spin_lock(&mm->page_table_lock);
2612 while (vaddr < vma->vm_end && remainder) {
2618 * Some archs (sparc64, sh*) have multiple pte_ts to
2619 * each hugepage. We have to make sure we get the
2620 * first, for the page indexing below to work.
2622 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2623 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2626 * When coredumping, it suits get_dump_page if we just return
2627 * an error where there's an empty slot with no huge pagecache
2628 * to back it. This way, we avoid allocating a hugepage, and
2629 * the sparse dumpfile avoids allocating disk blocks, but its
2630 * huge holes still show up with zeroes where they need to be.
2632 if (absent && (flags & FOLL_DUMP) &&
2633 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2639 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2642 spin_unlock(&mm->page_table_lock);
2643 ret = hugetlb_fault(mm, vma, vaddr,
2644 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2645 spin_lock(&mm->page_table_lock);
2646 if (!(ret & VM_FAULT_ERROR))
2653 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2654 page = pte_page(huge_ptep_get(pte));
2657 pages[i] = mem_map_offset(page, pfn_offset);
2668 if (vaddr < vma->vm_end && remainder &&
2669 pfn_offset < pages_per_huge_page(h)) {
2671 * We use pfn_offset to avoid touching the pageframes
2672 * of this compound page.
2677 spin_unlock(&mm->page_table_lock);
2678 *length = remainder;
2681 return i ? i : -EFAULT;
2684 void hugetlb_change_protection(struct vm_area_struct *vma,
2685 unsigned long address, unsigned long end, pgprot_t newprot)
2687 struct mm_struct *mm = vma->vm_mm;
2688 unsigned long start = address;
2691 struct hstate *h = hstate_vma(vma);
2693 BUG_ON(address >= end);
2694 flush_cache_range(vma, address, end);
2696 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2697 spin_lock(&mm->page_table_lock);
2698 for (; address < end; address += huge_page_size(h)) {
2699 ptep = huge_pte_offset(mm, address);
2702 if (huge_pmd_unshare(mm, &address, ptep))
2704 if (!huge_pte_none(huge_ptep_get(ptep))) {
2705 pte = huge_ptep_get_and_clear(mm, address, ptep);
2706 pte = pte_mkhuge(pte_modify(pte, newprot));
2707 set_huge_pte_at(mm, address, ptep, pte);
2710 spin_unlock(&mm->page_table_lock);
2711 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2713 flush_tlb_range(vma, start, end);
2716 int hugetlb_reserve_pages(struct inode *inode,
2718 struct vm_area_struct *vma,
2722 struct hstate *h = hstate_inode(inode);
2725 * Only apply hugepage reservation if asked. At fault time, an
2726 * attempt will be made for VM_NORESERVE to allocate a page
2727 * and filesystem quota without using reserves
2729 if (acctflag & VM_NORESERVE)
2733 * Shared mappings base their reservation on the number of pages that
2734 * are already allocated on behalf of the file. Private mappings need
2735 * to reserve the full area even if read-only as mprotect() may be
2736 * called to make the mapping read-write. Assume !vma is a shm mapping
2738 if (!vma || vma->vm_flags & VM_MAYSHARE)
2739 chg = region_chg(&inode->i_mapping->private_list, from, to);
2741 struct resv_map *resv_map = resv_map_alloc();
2747 set_vma_resv_map(vma, resv_map);
2748 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2754 /* There must be enough filesystem quota for the mapping */
2755 if (hugetlb_get_quota(inode->i_mapping, chg))
2759 * Check enough hugepages are available for the reservation.
2760 * Hand back the quota if there are not
2762 ret = hugetlb_acct_memory(h, chg);
2764 hugetlb_put_quota(inode->i_mapping, chg);
2769 * Account for the reservations made. Shared mappings record regions
2770 * that have reservations as they are shared by multiple VMAs.
2771 * When the last VMA disappears, the region map says how much
2772 * the reservation was and the page cache tells how much of
2773 * the reservation was consumed. Private mappings are per-VMA and
2774 * only the consumed reservations are tracked. When the VMA
2775 * disappears, the original reservation is the VMA size and the
2776 * consumed reservations are stored in the map. Hence, nothing
2777 * else has to be done for private mappings here
2779 if (!vma || vma->vm_flags & VM_MAYSHARE)
2780 region_add(&inode->i_mapping->private_list, from, to);
2784 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2786 struct hstate *h = hstate_inode(inode);
2787 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2789 spin_lock(&inode->i_lock);
2790 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2791 spin_unlock(&inode->i_lock);
2793 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2794 hugetlb_acct_memory(h, -(chg - freed));