2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
10 #include <linux/seq_file.h>
11 #include <linux/sysctl.h>
12 #include <linux/highmem.h>
13 #include <linux/mmu_notifier.h>
14 #include <linux/nodemask.h>
15 #include <linux/pagemap.h>
16 #include <linux/mempolicy.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
23 #include <asm/pgtable.h>
26 #include <linux/hugetlb.h>
29 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
30 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
31 unsigned long hugepages_treat_as_movable;
33 static int max_hstate;
34 unsigned int default_hstate_idx;
35 struct hstate hstates[HUGE_MAX_HSTATE];
37 __initdata LIST_HEAD(huge_boot_pages);
39 /* for command line parsing */
40 static struct hstate * __initdata parsed_hstate;
41 static unsigned long __initdata default_hstate_max_huge_pages;
42 static unsigned long __initdata default_hstate_size;
44 #define for_each_hstate(h) \
45 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
48 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
50 static DEFINE_SPINLOCK(hugetlb_lock);
53 * Region tracking -- allows tracking of reservations and instantiated pages
54 * across the pages in a mapping.
56 * The region data structures are protected by a combination of the mmap_sem
57 * and the hugetlb_instantion_mutex. To access or modify a region the caller
58 * must either hold the mmap_sem for write, or the mmap_sem for read and
59 * the hugetlb_instantiation mutex:
61 * down_write(&mm->mmap_sem);
63 * down_read(&mm->mmap_sem);
64 * mutex_lock(&hugetlb_instantiation_mutex);
67 struct list_head link;
72 static long region_add(struct list_head *head, long f, long t)
74 struct file_region *rg, *nrg, *trg;
76 /* Locate the region we are either in or before. */
77 list_for_each_entry(rg, head, link)
81 /* Round our left edge to the current segment if it encloses us. */
85 /* Check for and consume any regions we now overlap with. */
87 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
88 if (&rg->link == head)
93 /* If this area reaches higher then extend our area to
94 * include it completely. If this is not the first area
95 * which we intend to reuse, free it. */
108 static long region_chg(struct list_head *head, long f, long t)
110 struct file_region *rg, *nrg;
113 /* Locate the region we are before or in. */
114 list_for_each_entry(rg, head, link)
118 /* If we are below the current region then a new region is required.
119 * Subtle, allocate a new region at the position but make it zero
120 * size such that we can guarantee to record the reservation. */
121 if (&rg->link == head || t < rg->from) {
122 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
127 INIT_LIST_HEAD(&nrg->link);
128 list_add(&nrg->link, rg->link.prev);
133 /* Round our left edge to the current segment if it encloses us. */
138 /* Check for and consume any regions we now overlap with. */
139 list_for_each_entry(rg, rg->link.prev, link) {
140 if (&rg->link == head)
145 /* We overlap with this area, if it extends futher than
146 * us then we must extend ourselves. Account for its
147 * existing reservation. */
152 chg -= rg->to - rg->from;
157 static long region_truncate(struct list_head *head, long end)
159 struct file_region *rg, *trg;
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg, head, link)
166 if (&rg->link == head)
169 /* If we are in the middle of a region then adjust it. */
170 if (end > rg->from) {
173 rg = list_entry(rg->link.next, typeof(*rg), link);
176 /* Drop any remaining regions. */
177 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
178 if (&rg->link == head)
180 chg += rg->to - rg->from;
187 static long region_count(struct list_head *head, long f, long t)
189 struct file_region *rg;
192 /* Locate each segment we overlap with, and count that overlap. */
193 list_for_each_entry(rg, head, link) {
202 seg_from = max(rg->from, f);
203 seg_to = min(rg->to, t);
205 chg += seg_to - seg_from;
212 * Convert the address within this vma to the page offset within
213 * the mapping, in pagecache page units; huge pages here.
215 static pgoff_t vma_hugecache_offset(struct hstate *h,
216 struct vm_area_struct *vma, unsigned long address)
218 return ((address - vma->vm_start) >> huge_page_shift(h)) +
219 (vma->vm_pgoff >> huge_page_order(h));
223 * Return the size of the pages allocated when backing a VMA. In the majority
224 * cases this will be same size as used by the page table entries.
226 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
228 struct hstate *hstate;
230 if (!is_vm_hugetlb_page(vma))
233 hstate = hstate_vma(vma);
235 return 1UL << (hstate->order + PAGE_SHIFT);
237 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
240 * Return the page size being used by the MMU to back a VMA. In the majority
241 * of cases, the page size used by the kernel matches the MMU size. On
242 * architectures where it differs, an architecture-specific version of this
243 * function is required.
245 #ifndef vma_mmu_pagesize
246 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
248 return vma_kernel_pagesize(vma);
253 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
254 * bits of the reservation map pointer, which are always clear due to
257 #define HPAGE_RESV_OWNER (1UL << 0)
258 #define HPAGE_RESV_UNMAPPED (1UL << 1)
259 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
262 * These helpers are used to track how many pages are reserved for
263 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
264 * is guaranteed to have their future faults succeed.
266 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
267 * the reserve counters are updated with the hugetlb_lock held. It is safe
268 * to reset the VMA at fork() time as it is not in use yet and there is no
269 * chance of the global counters getting corrupted as a result of the values.
271 * The private mapping reservation is represented in a subtly different
272 * manner to a shared mapping. A shared mapping has a region map associated
273 * with the underlying file, this region map represents the backing file
274 * pages which have ever had a reservation assigned which this persists even
275 * after the page is instantiated. A private mapping has a region map
276 * associated with the original mmap which is attached to all VMAs which
277 * reference it, this region map represents those offsets which have consumed
278 * reservation ie. where pages have been instantiated.
280 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
282 return (unsigned long)vma->vm_private_data;
285 static void set_vma_private_data(struct vm_area_struct *vma,
288 vma->vm_private_data = (void *)value;
293 struct list_head regions;
296 static struct resv_map *resv_map_alloc(void)
298 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
302 kref_init(&resv_map->refs);
303 INIT_LIST_HEAD(&resv_map->regions);
308 static void resv_map_release(struct kref *ref)
310 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
312 /* Clear out any active regions before we release the map. */
313 region_truncate(&resv_map->regions, 0);
317 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
319 VM_BUG_ON(!is_vm_hugetlb_page(vma));
320 if (!(vma->vm_flags & VM_MAYSHARE))
321 return (struct resv_map *)(get_vma_private_data(vma) &
326 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
328 VM_BUG_ON(!is_vm_hugetlb_page(vma));
329 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
331 set_vma_private_data(vma, (get_vma_private_data(vma) &
332 HPAGE_RESV_MASK) | (unsigned long)map);
335 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
337 VM_BUG_ON(!is_vm_hugetlb_page(vma));
338 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
340 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
343 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
345 VM_BUG_ON(!is_vm_hugetlb_page(vma));
347 return (get_vma_private_data(vma) & flag) != 0;
350 /* Decrement the reserved pages in the hugepage pool by one */
351 static void decrement_hugepage_resv_vma(struct hstate *h,
352 struct vm_area_struct *vma)
354 if (vma->vm_flags & VM_NORESERVE)
357 if (vma->vm_flags & VM_MAYSHARE) {
358 /* Shared mappings always use reserves */
359 h->resv_huge_pages--;
360 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
362 * Only the process that called mmap() has reserves for
365 h->resv_huge_pages--;
369 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
370 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
372 VM_BUG_ON(!is_vm_hugetlb_page(vma));
373 if (!(vma->vm_flags & VM_MAYSHARE))
374 vma->vm_private_data = (void *)0;
377 /* Returns true if the VMA has associated reserve pages */
378 static int vma_has_reserves(struct vm_area_struct *vma)
380 if (vma->vm_flags & VM_MAYSHARE)
382 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
387 static void clear_gigantic_page(struct page *page,
388 unsigned long addr, unsigned long sz)
391 struct page *p = page;
394 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
396 clear_user_highpage(p, addr + i * PAGE_SIZE);
399 static void clear_huge_page(struct page *page,
400 unsigned long addr, unsigned long sz)
404 if (unlikely(sz > MAX_ORDER_NR_PAGES)) {
405 clear_gigantic_page(page, addr, sz);
410 for (i = 0; i < sz/PAGE_SIZE; i++) {
412 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
416 static void copy_gigantic_page(struct page *dst, struct page *src,
417 unsigned long addr, struct vm_area_struct *vma)
420 struct hstate *h = hstate_vma(vma);
421 struct page *dst_base = dst;
422 struct page *src_base = src;
424 for (i = 0; i < pages_per_huge_page(h); ) {
426 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
429 dst = mem_map_next(dst, dst_base, i);
430 src = mem_map_next(src, src_base, i);
433 static void copy_huge_page(struct page *dst, struct page *src,
434 unsigned long addr, struct vm_area_struct *vma)
437 struct hstate *h = hstate_vma(vma);
439 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
440 copy_gigantic_page(dst, src, addr, vma);
445 for (i = 0; i < pages_per_huge_page(h); i++) {
447 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
451 static void enqueue_huge_page(struct hstate *h, struct page *page)
453 int nid = page_to_nid(page);
454 list_add(&page->lru, &h->hugepage_freelists[nid]);
455 h->free_huge_pages++;
456 h->free_huge_pages_node[nid]++;
459 static struct page *dequeue_huge_page_vma(struct hstate *h,
460 struct vm_area_struct *vma,
461 unsigned long address, int avoid_reserve)
464 struct page *page = NULL;
465 struct mempolicy *mpol;
466 nodemask_t *nodemask;
467 struct zonelist *zonelist = huge_zonelist(vma, address,
468 htlb_alloc_mask, &mpol, &nodemask);
473 * A child process with MAP_PRIVATE mappings created by their parent
474 * have no page reserves. This check ensures that reservations are
475 * not "stolen". The child may still get SIGKILLed
477 if (!vma_has_reserves(vma) &&
478 h->free_huge_pages - h->resv_huge_pages == 0)
481 /* If reserves cannot be used, ensure enough pages are in the pool */
482 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
485 for_each_zone_zonelist_nodemask(zone, z, zonelist,
486 MAX_NR_ZONES - 1, nodemask) {
487 nid = zone_to_nid(zone);
488 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
489 !list_empty(&h->hugepage_freelists[nid])) {
490 page = list_entry(h->hugepage_freelists[nid].next,
492 list_del(&page->lru);
493 h->free_huge_pages--;
494 h->free_huge_pages_node[nid]--;
497 decrement_hugepage_resv_vma(h, vma);
506 static void update_and_free_page(struct hstate *h, struct page *page)
510 VM_BUG_ON(h->order >= MAX_ORDER);
513 h->nr_huge_pages_node[page_to_nid(page)]--;
514 for (i = 0; i < pages_per_huge_page(h); i++) {
515 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
516 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
517 1 << PG_private | 1<< PG_writeback);
519 set_compound_page_dtor(page, NULL);
520 set_page_refcounted(page);
521 arch_release_hugepage(page);
522 __free_pages(page, huge_page_order(h));
525 struct hstate *size_to_hstate(unsigned long size)
530 if (huge_page_size(h) == size)
536 static void free_huge_page(struct page *page)
539 * Can't pass hstate in here because it is called from the
540 * compound page destructor.
542 struct hstate *h = page_hstate(page);
543 int nid = page_to_nid(page);
544 struct address_space *mapping;
546 mapping = (struct address_space *) page_private(page);
547 set_page_private(page, 0);
548 BUG_ON(page_count(page));
549 INIT_LIST_HEAD(&page->lru);
551 spin_lock(&hugetlb_lock);
552 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
553 update_and_free_page(h, page);
554 h->surplus_huge_pages--;
555 h->surplus_huge_pages_node[nid]--;
557 enqueue_huge_page(h, page);
559 spin_unlock(&hugetlb_lock);
561 hugetlb_put_quota(mapping, 1);
564 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
566 set_compound_page_dtor(page, free_huge_page);
567 spin_lock(&hugetlb_lock);
569 h->nr_huge_pages_node[nid]++;
570 spin_unlock(&hugetlb_lock);
571 put_page(page); /* free it into the hugepage allocator */
574 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
577 int nr_pages = 1 << order;
578 struct page *p = page + 1;
580 /* we rely on prep_new_huge_page to set the destructor */
581 set_compound_order(page, order);
583 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
585 p->first_page = page;
589 int PageHuge(struct page *page)
591 compound_page_dtor *dtor;
593 if (!PageCompound(page))
596 page = compound_head(page);
597 dtor = get_compound_page_dtor(page);
599 return dtor == free_huge_page;
602 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
606 if (h->order >= MAX_ORDER)
609 page = alloc_pages_exact_node(nid,
610 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
611 __GFP_REPEAT|__GFP_NOWARN,
614 if (arch_prepare_hugepage(page)) {
615 __free_pages(page, huge_page_order(h));
618 prep_new_huge_page(h, page, nid);
625 * common helper function for hstate_next_node_to_{alloc|free}.
626 * return next node in node_online_map, wrapping at end.
628 static int next_node_allowed(int nid)
630 nid = next_node(nid, node_online_map);
631 if (nid == MAX_NUMNODES)
632 nid = first_node(node_online_map);
633 VM_BUG_ON(nid >= MAX_NUMNODES);
639 * Use a helper variable to find the next node and then
640 * copy it back to next_nid_to_alloc afterwards:
641 * otherwise there's a window in which a racer might
642 * pass invalid nid MAX_NUMNODES to alloc_pages_exact_node.
643 * But we don't need to use a spin_lock here: it really
644 * doesn't matter if occasionally a racer chooses the
645 * same nid as we do. Move nid forward in the mask even
646 * if we just successfully allocated a hugepage so that
647 * the next caller gets hugepages on the next node.
649 static int hstate_next_node_to_alloc(struct hstate *h)
653 nid = h->next_nid_to_alloc;
654 next_nid = next_node_allowed(nid);
655 h->next_nid_to_alloc = next_nid;
659 static int alloc_fresh_huge_page(struct hstate *h)
666 start_nid = hstate_next_node_to_alloc(h);
667 next_nid = start_nid;
670 page = alloc_fresh_huge_page_node(h, next_nid);
675 next_nid = hstate_next_node_to_alloc(h);
676 } while (next_nid != start_nid);
679 count_vm_event(HTLB_BUDDY_PGALLOC);
681 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
687 * helper for free_pool_huge_page() - return the next node
688 * from which to free a huge page. Advance the next node id
689 * whether or not we find a free huge page to free so that the
690 * next attempt to free addresses the next node.
692 static int hstate_next_node_to_free(struct hstate *h)
696 nid = h->next_nid_to_free;
697 next_nid = next_node_allowed(nid);
698 h->next_nid_to_free = next_nid;
703 * Free huge page from pool from next node to free.
704 * Attempt to keep persistent huge pages more or less
705 * balanced over allowed nodes.
706 * Called with hugetlb_lock locked.
708 static int free_pool_huge_page(struct hstate *h, bool acct_surplus)
714 start_nid = hstate_next_node_to_free(h);
715 next_nid = start_nid;
719 * If we're returning unused surplus pages, only examine
720 * nodes with surplus pages.
722 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
723 !list_empty(&h->hugepage_freelists[next_nid])) {
725 list_entry(h->hugepage_freelists[next_nid].next,
727 list_del(&page->lru);
728 h->free_huge_pages--;
729 h->free_huge_pages_node[next_nid]--;
731 h->surplus_huge_pages--;
732 h->surplus_huge_pages_node[next_nid]--;
734 update_and_free_page(h, page);
738 next_nid = hstate_next_node_to_free(h);
739 } while (next_nid != start_nid);
744 static struct page *alloc_buddy_huge_page(struct hstate *h,
745 struct vm_area_struct *vma, unsigned long address)
750 if (h->order >= MAX_ORDER)
754 * Assume we will successfully allocate the surplus page to
755 * prevent racing processes from causing the surplus to exceed
758 * This however introduces a different race, where a process B
759 * tries to grow the static hugepage pool while alloc_pages() is
760 * called by process A. B will only examine the per-node
761 * counters in determining if surplus huge pages can be
762 * converted to normal huge pages in adjust_pool_surplus(). A
763 * won't be able to increment the per-node counter, until the
764 * lock is dropped by B, but B doesn't drop hugetlb_lock until
765 * no more huge pages can be converted from surplus to normal
766 * state (and doesn't try to convert again). Thus, we have a
767 * case where a surplus huge page exists, the pool is grown, and
768 * the surplus huge page still exists after, even though it
769 * should just have been converted to a normal huge page. This
770 * does not leak memory, though, as the hugepage will be freed
771 * once it is out of use. It also does not allow the counters to
772 * go out of whack in adjust_pool_surplus() as we don't modify
773 * the node values until we've gotten the hugepage and only the
774 * per-node value is checked there.
776 spin_lock(&hugetlb_lock);
777 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
778 spin_unlock(&hugetlb_lock);
782 h->surplus_huge_pages++;
784 spin_unlock(&hugetlb_lock);
786 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
787 __GFP_REPEAT|__GFP_NOWARN,
790 if (page && arch_prepare_hugepage(page)) {
791 __free_pages(page, huge_page_order(h));
795 spin_lock(&hugetlb_lock);
798 * This page is now managed by the hugetlb allocator and has
799 * no users -- drop the buddy allocator's reference.
801 put_page_testzero(page);
802 VM_BUG_ON(page_count(page));
803 nid = page_to_nid(page);
804 set_compound_page_dtor(page, free_huge_page);
806 * We incremented the global counters already
808 h->nr_huge_pages_node[nid]++;
809 h->surplus_huge_pages_node[nid]++;
810 __count_vm_event(HTLB_BUDDY_PGALLOC);
813 h->surplus_huge_pages--;
814 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
816 spin_unlock(&hugetlb_lock);
822 * Increase the hugetlb pool such that it can accomodate a reservation
825 static int gather_surplus_pages(struct hstate *h, int delta)
827 struct list_head surplus_list;
828 struct page *page, *tmp;
830 int needed, allocated;
832 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
834 h->resv_huge_pages += delta;
839 INIT_LIST_HEAD(&surplus_list);
843 spin_unlock(&hugetlb_lock);
844 for (i = 0; i < needed; i++) {
845 page = alloc_buddy_huge_page(h, NULL, 0);
848 * We were not able to allocate enough pages to
849 * satisfy the entire reservation so we free what
850 * we've allocated so far.
852 spin_lock(&hugetlb_lock);
857 list_add(&page->lru, &surplus_list);
862 * After retaking hugetlb_lock, we need to recalculate 'needed'
863 * because either resv_huge_pages or free_huge_pages may have changed.
865 spin_lock(&hugetlb_lock);
866 needed = (h->resv_huge_pages + delta) -
867 (h->free_huge_pages + allocated);
872 * The surplus_list now contains _at_least_ the number of extra pages
873 * needed to accomodate the reservation. Add the appropriate number
874 * of pages to the hugetlb pool and free the extras back to the buddy
875 * allocator. Commit the entire reservation here to prevent another
876 * process from stealing the pages as they are added to the pool but
877 * before they are reserved.
880 h->resv_huge_pages += delta;
883 /* Free the needed pages to the hugetlb pool */
884 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
887 list_del(&page->lru);
888 enqueue_huge_page(h, page);
891 /* Free unnecessary surplus pages to the buddy allocator */
892 if (!list_empty(&surplus_list)) {
893 spin_unlock(&hugetlb_lock);
894 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
895 list_del(&page->lru);
897 * The page has a reference count of zero already, so
898 * call free_huge_page directly instead of using
899 * put_page. This must be done with hugetlb_lock
900 * unlocked which is safe because free_huge_page takes
901 * hugetlb_lock before deciding how to free the page.
903 free_huge_page(page);
905 spin_lock(&hugetlb_lock);
912 * When releasing a hugetlb pool reservation, any surplus pages that were
913 * allocated to satisfy the reservation must be explicitly freed if they were
915 * Called with hugetlb_lock held.
917 static void return_unused_surplus_pages(struct hstate *h,
918 unsigned long unused_resv_pages)
920 unsigned long nr_pages;
922 /* Uncommit the reservation */
923 h->resv_huge_pages -= unused_resv_pages;
925 /* Cannot return gigantic pages currently */
926 if (h->order >= MAX_ORDER)
929 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
932 * We want to release as many surplus pages as possible, spread
933 * evenly across all nodes. Iterate across all nodes until we
934 * can no longer free unreserved surplus pages. This occurs when
935 * the nodes with surplus pages have no free pages.
936 * free_pool_huge_page() will balance the the frees across the
937 * on-line nodes for us and will handle the hstate accounting.
940 if (!free_pool_huge_page(h, 1))
946 * Determine if the huge page at addr within the vma has an associated
947 * reservation. Where it does not we will need to logically increase
948 * reservation and actually increase quota before an allocation can occur.
949 * Where any new reservation would be required the reservation change is
950 * prepared, but not committed. Once the page has been quota'd allocated
951 * an instantiated the change should be committed via vma_commit_reservation.
952 * No action is required on failure.
954 static long vma_needs_reservation(struct hstate *h,
955 struct vm_area_struct *vma, unsigned long addr)
957 struct address_space *mapping = vma->vm_file->f_mapping;
958 struct inode *inode = mapping->host;
960 if (vma->vm_flags & VM_MAYSHARE) {
961 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
962 return region_chg(&inode->i_mapping->private_list,
965 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
970 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
971 struct resv_map *reservations = vma_resv_map(vma);
973 err = region_chg(&reservations->regions, idx, idx + 1);
979 static void vma_commit_reservation(struct hstate *h,
980 struct vm_area_struct *vma, unsigned long addr)
982 struct address_space *mapping = vma->vm_file->f_mapping;
983 struct inode *inode = mapping->host;
985 if (vma->vm_flags & VM_MAYSHARE) {
986 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
987 region_add(&inode->i_mapping->private_list, idx, idx + 1);
989 } 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 /* Mark this page used in the map. */
994 region_add(&reservations->regions, idx, idx + 1);
998 static struct page *alloc_huge_page(struct vm_area_struct *vma,
999 unsigned long addr, int avoid_reserve)
1001 struct hstate *h = hstate_vma(vma);
1003 struct address_space *mapping = vma->vm_file->f_mapping;
1004 struct inode *inode = mapping->host;
1008 * Processes that did not create the mapping will have no reserves and
1009 * will not have accounted against quota. Check that the quota can be
1010 * made before satisfying the allocation
1011 * MAP_NORESERVE mappings may also need pages and quota allocated
1012 * if no reserve mapping overlaps.
1014 chg = vma_needs_reservation(h, vma, addr);
1016 return ERR_PTR(chg);
1018 if (hugetlb_get_quota(inode->i_mapping, chg))
1019 return ERR_PTR(-ENOSPC);
1021 spin_lock(&hugetlb_lock);
1022 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1023 spin_unlock(&hugetlb_lock);
1026 page = alloc_buddy_huge_page(h, vma, addr);
1028 hugetlb_put_quota(inode->i_mapping, chg);
1029 return ERR_PTR(-VM_FAULT_OOM);
1033 set_page_refcounted(page);
1034 set_page_private(page, (unsigned long) mapping);
1036 vma_commit_reservation(h, vma, addr);
1041 int __weak alloc_bootmem_huge_page(struct hstate *h)
1043 struct huge_bootmem_page *m;
1044 int nr_nodes = nodes_weight(node_online_map);
1049 addr = __alloc_bootmem_node_nopanic(
1050 NODE_DATA(hstate_next_node_to_alloc(h)),
1051 huge_page_size(h), huge_page_size(h), 0);
1055 * Use the beginning of the huge page to store the
1056 * huge_bootmem_page struct (until gather_bootmem
1057 * puts them into the mem_map).
1067 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1068 /* Put them into a private list first because mem_map is not up yet */
1069 list_add(&m->list, &huge_boot_pages);
1074 static void prep_compound_huge_page(struct page *page, int order)
1076 if (unlikely(order > (MAX_ORDER - 1)))
1077 prep_compound_gigantic_page(page, order);
1079 prep_compound_page(page, order);
1082 /* Put bootmem huge pages into the standard lists after mem_map is up */
1083 static void __init gather_bootmem_prealloc(void)
1085 struct huge_bootmem_page *m;
1087 list_for_each_entry(m, &huge_boot_pages, list) {
1088 struct page *page = virt_to_page(m);
1089 struct hstate *h = m->hstate;
1090 __ClearPageReserved(page);
1091 WARN_ON(page_count(page) != 1);
1092 prep_compound_huge_page(page, h->order);
1093 prep_new_huge_page(h, page, page_to_nid(page));
1097 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1101 for (i = 0; i < h->max_huge_pages; ++i) {
1102 if (h->order >= MAX_ORDER) {
1103 if (!alloc_bootmem_huge_page(h))
1105 } else if (!alloc_fresh_huge_page(h))
1108 h->max_huge_pages = i;
1111 static void __init hugetlb_init_hstates(void)
1115 for_each_hstate(h) {
1116 /* oversize hugepages were init'ed in early boot */
1117 if (h->order < MAX_ORDER)
1118 hugetlb_hstate_alloc_pages(h);
1122 static char * __init memfmt(char *buf, unsigned long n)
1124 if (n >= (1UL << 30))
1125 sprintf(buf, "%lu GB", n >> 30);
1126 else if (n >= (1UL << 20))
1127 sprintf(buf, "%lu MB", n >> 20);
1129 sprintf(buf, "%lu KB", n >> 10);
1133 static void __init report_hugepages(void)
1137 for_each_hstate(h) {
1139 printk(KERN_INFO "HugeTLB registered %s page size, "
1140 "pre-allocated %ld pages\n",
1141 memfmt(buf, huge_page_size(h)),
1142 h->free_huge_pages);
1146 #ifdef CONFIG_HIGHMEM
1147 static void try_to_free_low(struct hstate *h, unsigned long count)
1151 if (h->order >= MAX_ORDER)
1154 for (i = 0; i < MAX_NUMNODES; ++i) {
1155 struct page *page, *next;
1156 struct list_head *freel = &h->hugepage_freelists[i];
1157 list_for_each_entry_safe(page, next, freel, lru) {
1158 if (count >= h->nr_huge_pages)
1160 if (PageHighMem(page))
1162 list_del(&page->lru);
1163 update_and_free_page(h, page);
1164 h->free_huge_pages--;
1165 h->free_huge_pages_node[page_to_nid(page)]--;
1170 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1176 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1177 * balanced by operating on them in a round-robin fashion.
1178 * Returns 1 if an adjustment was made.
1180 static int adjust_pool_surplus(struct hstate *h, int delta)
1182 int start_nid, next_nid;
1185 VM_BUG_ON(delta != -1 && delta != 1);
1188 start_nid = hstate_next_node_to_alloc(h);
1190 start_nid = hstate_next_node_to_free(h);
1191 next_nid = start_nid;
1197 * To shrink on this node, there must be a surplus page
1199 if (!h->surplus_huge_pages_node[nid]) {
1200 next_nid = hstate_next_node_to_alloc(h);
1206 * Surplus cannot exceed the total number of pages
1208 if (h->surplus_huge_pages_node[nid] >=
1209 h->nr_huge_pages_node[nid]) {
1210 next_nid = hstate_next_node_to_free(h);
1215 h->surplus_huge_pages += delta;
1216 h->surplus_huge_pages_node[nid] += delta;
1219 } while (next_nid != start_nid);
1224 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1225 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1227 unsigned long min_count, ret;
1229 if (h->order >= MAX_ORDER)
1230 return h->max_huge_pages;
1233 * Increase the pool size
1234 * First take pages out of surplus state. Then make up the
1235 * remaining difference by allocating fresh huge pages.
1237 * We might race with alloc_buddy_huge_page() here and be unable
1238 * to convert a surplus huge page to a normal huge page. That is
1239 * not critical, though, it just means the overall size of the
1240 * pool might be one hugepage larger than it needs to be, but
1241 * within all the constraints specified by the sysctls.
1243 spin_lock(&hugetlb_lock);
1244 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1245 if (!adjust_pool_surplus(h, -1))
1249 while (count > persistent_huge_pages(h)) {
1251 * If this allocation races such that we no longer need the
1252 * page, free_huge_page will handle it by freeing the page
1253 * and reducing the surplus.
1255 spin_unlock(&hugetlb_lock);
1256 ret = alloc_fresh_huge_page(h);
1257 spin_lock(&hugetlb_lock);
1264 * Decrease the pool size
1265 * First return free pages to the buddy allocator (being careful
1266 * to keep enough around to satisfy reservations). Then place
1267 * pages into surplus state as needed so the pool will shrink
1268 * to the desired size as pages become free.
1270 * By placing pages into the surplus state independent of the
1271 * overcommit value, we are allowing the surplus pool size to
1272 * exceed overcommit. There are few sane options here. Since
1273 * alloc_buddy_huge_page() is checking the global counter,
1274 * though, we'll note that we're not allowed to exceed surplus
1275 * and won't grow the pool anywhere else. Not until one of the
1276 * sysctls are changed, or the surplus pages go out of use.
1278 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1279 min_count = max(count, min_count);
1280 try_to_free_low(h, min_count);
1281 while (min_count < persistent_huge_pages(h)) {
1282 if (!free_pool_huge_page(h, 0))
1285 while (count < persistent_huge_pages(h)) {
1286 if (!adjust_pool_surplus(h, 1))
1290 ret = persistent_huge_pages(h);
1291 spin_unlock(&hugetlb_lock);
1295 #define HSTATE_ATTR_RO(_name) \
1296 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1298 #define HSTATE_ATTR(_name) \
1299 static struct kobj_attribute _name##_attr = \
1300 __ATTR(_name, 0644, _name##_show, _name##_store)
1302 static struct kobject *hugepages_kobj;
1303 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1305 static struct hstate *kobj_to_hstate(struct kobject *kobj)
1308 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1309 if (hstate_kobjs[i] == kobj)
1315 static ssize_t nr_hugepages_show(struct kobject *kobj,
1316 struct kobj_attribute *attr, char *buf)
1318 struct hstate *h = kobj_to_hstate(kobj);
1319 return sprintf(buf, "%lu\n", h->nr_huge_pages);
1321 static ssize_t nr_hugepages_store(struct kobject *kobj,
1322 struct kobj_attribute *attr, const char *buf, size_t count)
1325 unsigned long input;
1326 struct hstate *h = kobj_to_hstate(kobj);
1328 err = strict_strtoul(buf, 10, &input);
1332 h->max_huge_pages = set_max_huge_pages(h, input);
1336 HSTATE_ATTR(nr_hugepages);
1338 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1339 struct kobj_attribute *attr, char *buf)
1341 struct hstate *h = kobj_to_hstate(kobj);
1342 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1344 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1345 struct kobj_attribute *attr, const char *buf, size_t count)
1348 unsigned long input;
1349 struct hstate *h = kobj_to_hstate(kobj);
1351 err = strict_strtoul(buf, 10, &input);
1355 spin_lock(&hugetlb_lock);
1356 h->nr_overcommit_huge_pages = input;
1357 spin_unlock(&hugetlb_lock);
1361 HSTATE_ATTR(nr_overcommit_hugepages);
1363 static ssize_t free_hugepages_show(struct kobject *kobj,
1364 struct kobj_attribute *attr, char *buf)
1366 struct hstate *h = kobj_to_hstate(kobj);
1367 return sprintf(buf, "%lu\n", h->free_huge_pages);
1369 HSTATE_ATTR_RO(free_hugepages);
1371 static ssize_t resv_hugepages_show(struct kobject *kobj,
1372 struct kobj_attribute *attr, char *buf)
1374 struct hstate *h = kobj_to_hstate(kobj);
1375 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1377 HSTATE_ATTR_RO(resv_hugepages);
1379 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1380 struct kobj_attribute *attr, char *buf)
1382 struct hstate *h = kobj_to_hstate(kobj);
1383 return sprintf(buf, "%lu\n", h->surplus_huge_pages);
1385 HSTATE_ATTR_RO(surplus_hugepages);
1387 static struct attribute *hstate_attrs[] = {
1388 &nr_hugepages_attr.attr,
1389 &nr_overcommit_hugepages_attr.attr,
1390 &free_hugepages_attr.attr,
1391 &resv_hugepages_attr.attr,
1392 &surplus_hugepages_attr.attr,
1396 static struct attribute_group hstate_attr_group = {
1397 .attrs = hstate_attrs,
1400 static int __init hugetlb_sysfs_add_hstate(struct hstate *h)
1404 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name,
1406 if (!hstate_kobjs[h - hstates])
1409 retval = sysfs_create_group(hstate_kobjs[h - hstates],
1410 &hstate_attr_group);
1412 kobject_put(hstate_kobjs[h - hstates]);
1417 static void __init hugetlb_sysfs_init(void)
1422 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1423 if (!hugepages_kobj)
1426 for_each_hstate(h) {
1427 err = hugetlb_sysfs_add_hstate(h);
1429 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1434 static void __exit hugetlb_exit(void)
1438 for_each_hstate(h) {
1439 kobject_put(hstate_kobjs[h - hstates]);
1442 kobject_put(hugepages_kobj);
1444 module_exit(hugetlb_exit);
1446 static int __init hugetlb_init(void)
1448 /* Some platform decide whether they support huge pages at boot
1449 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1450 * there is no such support
1452 if (HPAGE_SHIFT == 0)
1455 if (!size_to_hstate(default_hstate_size)) {
1456 default_hstate_size = HPAGE_SIZE;
1457 if (!size_to_hstate(default_hstate_size))
1458 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1460 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1461 if (default_hstate_max_huge_pages)
1462 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1464 hugetlb_init_hstates();
1466 gather_bootmem_prealloc();
1470 hugetlb_sysfs_init();
1474 module_init(hugetlb_init);
1476 /* Should be called on processing a hugepagesz=... option */
1477 void __init hugetlb_add_hstate(unsigned order)
1482 if (size_to_hstate(PAGE_SIZE << order)) {
1483 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1486 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1488 h = &hstates[max_hstate++];
1490 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1491 h->nr_huge_pages = 0;
1492 h->free_huge_pages = 0;
1493 for (i = 0; i < MAX_NUMNODES; ++i)
1494 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1495 h->next_nid_to_alloc = first_node(node_online_map);
1496 h->next_nid_to_free = first_node(node_online_map);
1497 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1498 huge_page_size(h)/1024);
1503 static int __init hugetlb_nrpages_setup(char *s)
1506 static unsigned long *last_mhp;
1509 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1510 * so this hugepages= parameter goes to the "default hstate".
1513 mhp = &default_hstate_max_huge_pages;
1515 mhp = &parsed_hstate->max_huge_pages;
1517 if (mhp == last_mhp) {
1518 printk(KERN_WARNING "hugepages= specified twice without "
1519 "interleaving hugepagesz=, ignoring\n");
1523 if (sscanf(s, "%lu", mhp) <= 0)
1527 * Global state is always initialized later in hugetlb_init.
1528 * But we need to allocate >= MAX_ORDER hstates here early to still
1529 * use the bootmem allocator.
1531 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1532 hugetlb_hstate_alloc_pages(parsed_hstate);
1538 __setup("hugepages=", hugetlb_nrpages_setup);
1540 static int __init hugetlb_default_setup(char *s)
1542 default_hstate_size = memparse(s, &s);
1545 __setup("default_hugepagesz=", hugetlb_default_setup);
1547 static unsigned int cpuset_mems_nr(unsigned int *array)
1550 unsigned int nr = 0;
1552 for_each_node_mask(node, cpuset_current_mems_allowed)
1558 #ifdef CONFIG_SYSCTL
1559 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1560 void __user *buffer,
1561 size_t *length, loff_t *ppos)
1563 struct hstate *h = &default_hstate;
1567 tmp = h->max_huge_pages;
1570 table->maxlen = sizeof(unsigned long);
1571 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1574 h->max_huge_pages = set_max_huge_pages(h, tmp);
1579 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1580 void __user *buffer,
1581 size_t *length, loff_t *ppos)
1583 proc_dointvec(table, write, buffer, length, ppos);
1584 if (hugepages_treat_as_movable)
1585 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1587 htlb_alloc_mask = GFP_HIGHUSER;
1591 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1592 void __user *buffer,
1593 size_t *length, loff_t *ppos)
1595 struct hstate *h = &default_hstate;
1599 tmp = h->nr_overcommit_huge_pages;
1602 table->maxlen = sizeof(unsigned long);
1603 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1606 spin_lock(&hugetlb_lock);
1607 h->nr_overcommit_huge_pages = tmp;
1608 spin_unlock(&hugetlb_lock);
1614 #endif /* CONFIG_SYSCTL */
1616 void hugetlb_report_meminfo(struct seq_file *m)
1618 struct hstate *h = &default_hstate;
1620 "HugePages_Total: %5lu\n"
1621 "HugePages_Free: %5lu\n"
1622 "HugePages_Rsvd: %5lu\n"
1623 "HugePages_Surp: %5lu\n"
1624 "Hugepagesize: %8lu kB\n",
1628 h->surplus_huge_pages,
1629 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1632 int hugetlb_report_node_meminfo(int nid, char *buf)
1634 struct hstate *h = &default_hstate;
1636 "Node %d HugePages_Total: %5u\n"
1637 "Node %d HugePages_Free: %5u\n"
1638 "Node %d HugePages_Surp: %5u\n",
1639 nid, h->nr_huge_pages_node[nid],
1640 nid, h->free_huge_pages_node[nid],
1641 nid, h->surplus_huge_pages_node[nid]);
1644 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1645 unsigned long hugetlb_total_pages(void)
1647 struct hstate *h = &default_hstate;
1648 return h->nr_huge_pages * pages_per_huge_page(h);
1651 static int hugetlb_acct_memory(struct hstate *h, long delta)
1655 spin_lock(&hugetlb_lock);
1657 * When cpuset is configured, it breaks the strict hugetlb page
1658 * reservation as the accounting is done on a global variable. Such
1659 * reservation is completely rubbish in the presence of cpuset because
1660 * the reservation is not checked against page availability for the
1661 * current cpuset. Application can still potentially OOM'ed by kernel
1662 * with lack of free htlb page in cpuset that the task is in.
1663 * Attempt to enforce strict accounting with cpuset is almost
1664 * impossible (or too ugly) because cpuset is too fluid that
1665 * task or memory node can be dynamically moved between cpusets.
1667 * The change of semantics for shared hugetlb mapping with cpuset is
1668 * undesirable. However, in order to preserve some of the semantics,
1669 * we fall back to check against current free page availability as
1670 * a best attempt and hopefully to minimize the impact of changing
1671 * semantics that cpuset has.
1674 if (gather_surplus_pages(h, delta) < 0)
1677 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1678 return_unused_surplus_pages(h, delta);
1685 return_unused_surplus_pages(h, (unsigned long) -delta);
1688 spin_unlock(&hugetlb_lock);
1692 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1694 struct resv_map *reservations = vma_resv_map(vma);
1697 * This new VMA should share its siblings reservation map if present.
1698 * The VMA will only ever have a valid reservation map pointer where
1699 * it is being copied for another still existing VMA. As that VMA
1700 * has a reference to the reservation map it cannot dissappear until
1701 * after this open call completes. It is therefore safe to take a
1702 * new reference here without additional locking.
1705 kref_get(&reservations->refs);
1708 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1710 struct hstate *h = hstate_vma(vma);
1711 struct resv_map *reservations = vma_resv_map(vma);
1712 unsigned long reserve;
1713 unsigned long start;
1717 start = vma_hugecache_offset(h, vma, vma->vm_start);
1718 end = vma_hugecache_offset(h, vma, vma->vm_end);
1720 reserve = (end - start) -
1721 region_count(&reservations->regions, start, end);
1723 kref_put(&reservations->refs, resv_map_release);
1726 hugetlb_acct_memory(h, -reserve);
1727 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
1733 * We cannot handle pagefaults against hugetlb pages at all. They cause
1734 * handle_mm_fault() to try to instantiate regular-sized pages in the
1735 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1738 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1744 const struct vm_operations_struct hugetlb_vm_ops = {
1745 .fault = hugetlb_vm_op_fault,
1746 .open = hugetlb_vm_op_open,
1747 .close = hugetlb_vm_op_close,
1750 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1757 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1759 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1761 entry = pte_mkyoung(entry);
1762 entry = pte_mkhuge(entry);
1767 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1768 unsigned long address, pte_t *ptep)
1772 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1773 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1774 update_mmu_cache(vma, address, entry);
1779 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1780 struct vm_area_struct *vma)
1782 pte_t *src_pte, *dst_pte, entry;
1783 struct page *ptepage;
1786 struct hstate *h = hstate_vma(vma);
1787 unsigned long sz = huge_page_size(h);
1789 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1791 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1792 src_pte = huge_pte_offset(src, addr);
1795 dst_pte = huge_pte_alloc(dst, addr, sz);
1799 /* If the pagetables are shared don't copy or take references */
1800 if (dst_pte == src_pte)
1803 spin_lock(&dst->page_table_lock);
1804 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1805 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1807 huge_ptep_set_wrprotect(src, addr, src_pte);
1808 entry = huge_ptep_get(src_pte);
1809 ptepage = pte_page(entry);
1811 set_huge_pte_at(dst, addr, dst_pte, entry);
1813 spin_unlock(&src->page_table_lock);
1814 spin_unlock(&dst->page_table_lock);
1822 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1823 unsigned long end, struct page *ref_page)
1825 struct mm_struct *mm = vma->vm_mm;
1826 unsigned long address;
1831 struct hstate *h = hstate_vma(vma);
1832 unsigned long sz = huge_page_size(h);
1835 * A page gathering list, protected by per file i_mmap_lock. The
1836 * lock is used to avoid list corruption from multiple unmapping
1837 * of the same page since we are using page->lru.
1839 LIST_HEAD(page_list);
1841 WARN_ON(!is_vm_hugetlb_page(vma));
1842 BUG_ON(start & ~huge_page_mask(h));
1843 BUG_ON(end & ~huge_page_mask(h));
1845 mmu_notifier_invalidate_range_start(mm, start, end);
1846 spin_lock(&mm->page_table_lock);
1847 for (address = start; address < end; address += sz) {
1848 ptep = huge_pte_offset(mm, address);
1852 if (huge_pmd_unshare(mm, &address, ptep))
1856 * If a reference page is supplied, it is because a specific
1857 * page is being unmapped, not a range. Ensure the page we
1858 * are about to unmap is the actual page of interest.
1861 pte = huge_ptep_get(ptep);
1862 if (huge_pte_none(pte))
1864 page = pte_page(pte);
1865 if (page != ref_page)
1869 * Mark the VMA as having unmapped its page so that
1870 * future faults in this VMA will fail rather than
1871 * looking like data was lost
1873 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1876 pte = huge_ptep_get_and_clear(mm, address, ptep);
1877 if (huge_pte_none(pte))
1880 page = pte_page(pte);
1882 set_page_dirty(page);
1883 list_add(&page->lru, &page_list);
1885 spin_unlock(&mm->page_table_lock);
1886 flush_tlb_range(vma, start, end);
1887 mmu_notifier_invalidate_range_end(mm, start, end);
1888 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1889 list_del(&page->lru);
1894 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1895 unsigned long end, struct page *ref_page)
1897 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1898 __unmap_hugepage_range(vma, start, end, ref_page);
1899 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1903 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1904 * mappping it owns the reserve page for. The intention is to unmap the page
1905 * from other VMAs and let the children be SIGKILLed if they are faulting the
1908 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
1909 struct page *page, unsigned long address)
1911 struct hstate *h = hstate_vma(vma);
1912 struct vm_area_struct *iter_vma;
1913 struct address_space *mapping;
1914 struct prio_tree_iter iter;
1918 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1919 * from page cache lookup which is in HPAGE_SIZE units.
1921 address = address & huge_page_mask(h);
1922 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1923 + (vma->vm_pgoff >> PAGE_SHIFT);
1924 mapping = (struct address_space *)page_private(page);
1926 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1927 /* Do not unmap the current VMA */
1928 if (iter_vma == vma)
1932 * Unmap the page from other VMAs without their own reserves.
1933 * They get marked to be SIGKILLed if they fault in these
1934 * areas. This is because a future no-page fault on this VMA
1935 * could insert a zeroed page instead of the data existing
1936 * from the time of fork. This would look like data corruption
1938 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1939 unmap_hugepage_range(iter_vma,
1940 address, address + huge_page_size(h),
1947 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1948 unsigned long address, pte_t *ptep, pte_t pte,
1949 struct page *pagecache_page)
1951 struct hstate *h = hstate_vma(vma);
1952 struct page *old_page, *new_page;
1954 int outside_reserve = 0;
1956 old_page = pte_page(pte);
1959 /* If no-one else is actually using this page, avoid the copy
1960 * and just make the page writable */
1961 avoidcopy = (page_count(old_page) == 1);
1963 set_huge_ptep_writable(vma, address, ptep);
1968 * If the process that created a MAP_PRIVATE mapping is about to
1969 * perform a COW due to a shared page count, attempt to satisfy
1970 * the allocation without using the existing reserves. The pagecache
1971 * page is used to determine if the reserve at this address was
1972 * consumed or not. If reserves were used, a partial faulted mapping
1973 * at the time of fork() could consume its reserves on COW instead
1974 * of the full address range.
1976 if (!(vma->vm_flags & VM_MAYSHARE) &&
1977 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1978 old_page != pagecache_page)
1979 outside_reserve = 1;
1981 page_cache_get(old_page);
1982 new_page = alloc_huge_page(vma, address, outside_reserve);
1984 if (IS_ERR(new_page)) {
1985 page_cache_release(old_page);
1988 * If a process owning a MAP_PRIVATE mapping fails to COW,
1989 * it is due to references held by a child and an insufficient
1990 * huge page pool. To guarantee the original mappers
1991 * reliability, unmap the page from child processes. The child
1992 * may get SIGKILLed if it later faults.
1994 if (outside_reserve) {
1995 BUG_ON(huge_pte_none(pte));
1996 if (unmap_ref_private(mm, vma, old_page, address)) {
1997 BUG_ON(page_count(old_page) != 1);
1998 BUG_ON(huge_pte_none(pte));
1999 goto retry_avoidcopy;
2004 return -PTR_ERR(new_page);
2007 spin_unlock(&mm->page_table_lock);
2008 copy_huge_page(new_page, old_page, address, vma);
2009 __SetPageUptodate(new_page);
2010 spin_lock(&mm->page_table_lock);
2012 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2013 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2015 huge_ptep_clear_flush(vma, address, ptep);
2016 set_huge_pte_at(mm, address, ptep,
2017 make_huge_pte(vma, new_page, 1));
2018 /* Make the old page be freed below */
2019 new_page = old_page;
2021 page_cache_release(new_page);
2022 page_cache_release(old_page);
2026 /* Return the pagecache page at a given address within a VMA */
2027 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2028 struct vm_area_struct *vma, unsigned long address)
2030 struct address_space *mapping;
2033 mapping = vma->vm_file->f_mapping;
2034 idx = vma_hugecache_offset(h, vma, address);
2036 return find_lock_page(mapping, idx);
2040 * Return whether there is a pagecache page to back given address within VMA.
2041 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2043 static bool hugetlbfs_pagecache_present(struct hstate *h,
2044 struct vm_area_struct *vma, unsigned long address)
2046 struct address_space *mapping;
2050 mapping = vma->vm_file->f_mapping;
2051 idx = vma_hugecache_offset(h, vma, address);
2053 page = find_get_page(mapping, idx);
2056 return page != NULL;
2059 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2060 unsigned long address, pte_t *ptep, unsigned int flags)
2062 struct hstate *h = hstate_vma(vma);
2063 int ret = VM_FAULT_SIGBUS;
2067 struct address_space *mapping;
2071 * Currently, we are forced to kill the process in the event the
2072 * original mapper has unmapped pages from the child due to a failed
2073 * COW. Warn that such a situation has occured as it may not be obvious
2075 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2077 "PID %d killed due to inadequate hugepage pool\n",
2082 mapping = vma->vm_file->f_mapping;
2083 idx = vma_hugecache_offset(h, vma, address);
2086 * Use page lock to guard against racing truncation
2087 * before we get page_table_lock.
2090 page = find_lock_page(mapping, idx);
2092 size = i_size_read(mapping->host) >> huge_page_shift(h);
2095 page = alloc_huge_page(vma, address, 0);
2097 ret = -PTR_ERR(page);
2100 clear_huge_page(page, address, huge_page_size(h));
2101 __SetPageUptodate(page);
2103 if (vma->vm_flags & VM_MAYSHARE) {
2105 struct inode *inode = mapping->host;
2107 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2115 spin_lock(&inode->i_lock);
2116 inode->i_blocks += blocks_per_huge_page(h);
2117 spin_unlock(&inode->i_lock);
2123 * If we are going to COW a private mapping later, we examine the
2124 * pending reservations for this page now. This will ensure that
2125 * any allocations necessary to record that reservation occur outside
2128 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2129 if (vma_needs_reservation(h, vma, address) < 0) {
2131 goto backout_unlocked;
2134 spin_lock(&mm->page_table_lock);
2135 size = i_size_read(mapping->host) >> huge_page_shift(h);
2140 if (!huge_pte_none(huge_ptep_get(ptep)))
2143 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2144 && (vma->vm_flags & VM_SHARED)));
2145 set_huge_pte_at(mm, address, ptep, new_pte);
2147 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2148 /* Optimization, do the COW without a second fault */
2149 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2152 spin_unlock(&mm->page_table_lock);
2158 spin_unlock(&mm->page_table_lock);
2165 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2166 unsigned long address, unsigned int flags)
2171 struct page *pagecache_page = NULL;
2172 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2173 struct hstate *h = hstate_vma(vma);
2175 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2177 return VM_FAULT_OOM;
2180 * Serialize hugepage allocation and instantiation, so that we don't
2181 * get spurious allocation failures if two CPUs race to instantiate
2182 * the same page in the page cache.
2184 mutex_lock(&hugetlb_instantiation_mutex);
2185 entry = huge_ptep_get(ptep);
2186 if (huge_pte_none(entry)) {
2187 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2194 * If we are going to COW the mapping later, we examine the pending
2195 * reservations for this page now. This will ensure that any
2196 * allocations necessary to record that reservation occur outside the
2197 * spinlock. For private mappings, we also lookup the pagecache
2198 * page now as it is used to determine if a reservation has been
2201 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2202 if (vma_needs_reservation(h, vma, address) < 0) {
2207 if (!(vma->vm_flags & VM_MAYSHARE))
2208 pagecache_page = hugetlbfs_pagecache_page(h,
2212 spin_lock(&mm->page_table_lock);
2213 /* Check for a racing update before calling hugetlb_cow */
2214 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2215 goto out_page_table_lock;
2218 if (flags & FAULT_FLAG_WRITE) {
2219 if (!pte_write(entry)) {
2220 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2222 goto out_page_table_lock;
2224 entry = pte_mkdirty(entry);
2226 entry = pte_mkyoung(entry);
2227 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2228 flags & FAULT_FLAG_WRITE))
2229 update_mmu_cache(vma, address, entry);
2231 out_page_table_lock:
2232 spin_unlock(&mm->page_table_lock);
2234 if (pagecache_page) {
2235 unlock_page(pagecache_page);
2236 put_page(pagecache_page);
2240 mutex_unlock(&hugetlb_instantiation_mutex);
2245 /* Can be overriden by architectures */
2246 __attribute__((weak)) struct page *
2247 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2248 pud_t *pud, int write)
2254 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2255 struct page **pages, struct vm_area_struct **vmas,
2256 unsigned long *position, int *length, int i,
2259 unsigned long pfn_offset;
2260 unsigned long vaddr = *position;
2261 int remainder = *length;
2262 struct hstate *h = hstate_vma(vma);
2264 spin_lock(&mm->page_table_lock);
2265 while (vaddr < vma->vm_end && remainder) {
2271 * Some archs (sparc64, sh*) have multiple pte_ts to
2272 * each hugepage. We have to make sure we get the
2273 * first, for the page indexing below to work.
2275 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2276 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2279 * When coredumping, it suits get_dump_page if we just return
2280 * an error where there's an empty slot with no huge pagecache
2281 * to back it. This way, we avoid allocating a hugepage, and
2282 * the sparse dumpfile avoids allocating disk blocks, but its
2283 * huge holes still show up with zeroes where they need to be.
2285 if (absent && (flags & FOLL_DUMP) &&
2286 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2292 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2295 spin_unlock(&mm->page_table_lock);
2296 ret = hugetlb_fault(mm, vma, vaddr,
2297 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2298 spin_lock(&mm->page_table_lock);
2299 if (!(ret & VM_FAULT_ERROR))
2306 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2307 page = pte_page(huge_ptep_get(pte));
2310 pages[i] = mem_map_offset(page, pfn_offset);
2321 if (vaddr < vma->vm_end && remainder &&
2322 pfn_offset < pages_per_huge_page(h)) {
2324 * We use pfn_offset to avoid touching the pageframes
2325 * of this compound page.
2330 spin_unlock(&mm->page_table_lock);
2331 *length = remainder;
2334 return i ? i : -EFAULT;
2337 void hugetlb_change_protection(struct vm_area_struct *vma,
2338 unsigned long address, unsigned long end, pgprot_t newprot)
2340 struct mm_struct *mm = vma->vm_mm;
2341 unsigned long start = address;
2344 struct hstate *h = hstate_vma(vma);
2346 BUG_ON(address >= end);
2347 flush_cache_range(vma, address, end);
2349 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2350 spin_lock(&mm->page_table_lock);
2351 for (; address < end; address += huge_page_size(h)) {
2352 ptep = huge_pte_offset(mm, address);
2355 if (huge_pmd_unshare(mm, &address, ptep))
2357 if (!huge_pte_none(huge_ptep_get(ptep))) {
2358 pte = huge_ptep_get_and_clear(mm, address, ptep);
2359 pte = pte_mkhuge(pte_modify(pte, newprot));
2360 set_huge_pte_at(mm, address, ptep, pte);
2363 spin_unlock(&mm->page_table_lock);
2364 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2366 flush_tlb_range(vma, start, end);
2369 int hugetlb_reserve_pages(struct inode *inode,
2371 struct vm_area_struct *vma,
2375 struct hstate *h = hstate_inode(inode);
2378 * Only apply hugepage reservation if asked. At fault time, an
2379 * attempt will be made for VM_NORESERVE to allocate a page
2380 * and filesystem quota without using reserves
2382 if (acctflag & VM_NORESERVE)
2386 * Shared mappings base their reservation on the number of pages that
2387 * are already allocated on behalf of the file. Private mappings need
2388 * to reserve the full area even if read-only as mprotect() may be
2389 * called to make the mapping read-write. Assume !vma is a shm mapping
2391 if (!vma || vma->vm_flags & VM_MAYSHARE)
2392 chg = region_chg(&inode->i_mapping->private_list, from, to);
2394 struct resv_map *resv_map = resv_map_alloc();
2400 set_vma_resv_map(vma, resv_map);
2401 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2407 /* There must be enough filesystem quota for the mapping */
2408 if (hugetlb_get_quota(inode->i_mapping, chg))
2412 * Check enough hugepages are available for the reservation.
2413 * Hand back the quota if there are not
2415 ret = hugetlb_acct_memory(h, chg);
2417 hugetlb_put_quota(inode->i_mapping, chg);
2422 * Account for the reservations made. Shared mappings record regions
2423 * that have reservations as they are shared by multiple VMAs.
2424 * When the last VMA disappears, the region map says how much
2425 * the reservation was and the page cache tells how much of
2426 * the reservation was consumed. Private mappings are per-VMA and
2427 * only the consumed reservations are tracked. When the VMA
2428 * disappears, the original reservation is the VMA size and the
2429 * consumed reservations are stored in the map. Hence, nothing
2430 * else has to be done for private mappings here
2432 if (!vma || vma->vm_flags & VM_MAYSHARE)
2433 region_add(&inode->i_mapping->private_list, from, to);
2437 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2439 struct hstate *h = hstate_inode(inode);
2440 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2442 spin_lock(&inode->i_lock);
2443 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2444 spin_unlock(&inode->i_lock);
2446 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2447 hugetlb_acct_memory(h, -(chg - freed));