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/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/cpuset.h>
16 #include <linux/mutex.h>
19 #include <asm/pgtable.h>
21 #include <linux/hugetlb.h>
24 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
25 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
26 unsigned long hugepages_treat_as_movable;
28 static int max_hstate;
29 unsigned int default_hstate_idx;
30 struct hstate hstates[HUGE_MAX_HSTATE];
32 /* for command line parsing */
33 static struct hstate * __initdata parsed_hstate;
34 static unsigned long __initdata default_hstate_max_huge_pages;
36 #define for_each_hstate(h) \
37 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
40 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
42 static DEFINE_SPINLOCK(hugetlb_lock);
45 * Region tracking -- allows tracking of reservations and instantiated pages
46 * across the pages in a mapping.
48 * The region data structures are protected by a combination of the mmap_sem
49 * and the hugetlb_instantion_mutex. To access or modify a region the caller
50 * must either hold the mmap_sem for write, or the mmap_sem for read and
51 * the hugetlb_instantiation mutex:
53 * down_write(&mm->mmap_sem);
55 * down_read(&mm->mmap_sem);
56 * mutex_lock(&hugetlb_instantiation_mutex);
59 struct list_head link;
64 static long region_add(struct list_head *head, long f, long t)
66 struct file_region *rg, *nrg, *trg;
68 /* Locate the region we are either in or before. */
69 list_for_each_entry(rg, head, link)
73 /* Round our left edge to the current segment if it encloses us. */
77 /* Check for and consume any regions we now overlap with. */
79 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
80 if (&rg->link == head)
85 /* If this area reaches higher then extend our area to
86 * include it completely. If this is not the first area
87 * which we intend to reuse, free it. */
100 static long region_chg(struct list_head *head, long f, long t)
102 struct file_region *rg, *nrg;
105 /* Locate the region we are before or in. */
106 list_for_each_entry(rg, head, link)
110 /* If we are below the current region then a new region is required.
111 * Subtle, allocate a new region at the position but make it zero
112 * size such that we can guarantee to record the reservation. */
113 if (&rg->link == head || t < rg->from) {
114 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
119 INIT_LIST_HEAD(&nrg->link);
120 list_add(&nrg->link, rg->link.prev);
125 /* Round our left edge to the current segment if it encloses us. */
130 /* Check for and consume any regions we now overlap with. */
131 list_for_each_entry(rg, rg->link.prev, link) {
132 if (&rg->link == head)
137 /* We overlap with this area, if it extends futher than
138 * us then we must extend ourselves. Account for its
139 * existing reservation. */
144 chg -= rg->to - rg->from;
149 static long region_truncate(struct list_head *head, long end)
151 struct file_region *rg, *trg;
154 /* Locate the region we are either in or before. */
155 list_for_each_entry(rg, head, link)
158 if (&rg->link == head)
161 /* If we are in the middle of a region then adjust it. */
162 if (end > rg->from) {
165 rg = list_entry(rg->link.next, typeof(*rg), link);
168 /* Drop any remaining regions. */
169 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
170 if (&rg->link == head)
172 chg += rg->to - rg->from;
179 static long region_count(struct list_head *head, long f, long t)
181 struct file_region *rg;
184 /* Locate each segment we overlap with, and count that overlap. */
185 list_for_each_entry(rg, head, link) {
194 seg_from = max(rg->from, f);
195 seg_to = min(rg->to, t);
197 chg += seg_to - seg_from;
204 * Convert the address within this vma to the page offset within
205 * the mapping, in pagecache page units; huge pages here.
207 static pgoff_t vma_hugecache_offset(struct hstate *h,
208 struct vm_area_struct *vma, unsigned long address)
210 return ((address - vma->vm_start) >> huge_page_shift(h)) +
211 (vma->vm_pgoff >> huge_page_order(h));
215 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
216 * bits of the reservation map pointer, which are always clear due to
219 #define HPAGE_RESV_OWNER (1UL << 0)
220 #define HPAGE_RESV_UNMAPPED (1UL << 1)
221 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
224 * These helpers are used to track how many pages are reserved for
225 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
226 * is guaranteed to have their future faults succeed.
228 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
229 * the reserve counters are updated with the hugetlb_lock held. It is safe
230 * to reset the VMA at fork() time as it is not in use yet and there is no
231 * chance of the global counters getting corrupted as a result of the values.
233 * The private mapping reservation is represented in a subtly different
234 * manner to a shared mapping. A shared mapping has a region map associated
235 * with the underlying file, this region map represents the backing file
236 * pages which have ever had a reservation assigned which this persists even
237 * after the page is instantiated. A private mapping has a region map
238 * associated with the original mmap which is attached to all VMAs which
239 * reference it, this region map represents those offsets which have consumed
240 * reservation ie. where pages have been instantiated.
242 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
244 return (unsigned long)vma->vm_private_data;
247 static void set_vma_private_data(struct vm_area_struct *vma,
250 vma->vm_private_data = (void *)value;
255 struct list_head regions;
258 struct resv_map *resv_map_alloc(void)
260 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
264 kref_init(&resv_map->refs);
265 INIT_LIST_HEAD(&resv_map->regions);
270 void resv_map_release(struct kref *ref)
272 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
274 /* Clear out any active regions before we release the map. */
275 region_truncate(&resv_map->regions, 0);
279 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
281 VM_BUG_ON(!is_vm_hugetlb_page(vma));
282 if (!(vma->vm_flags & VM_SHARED))
283 return (struct resv_map *)(get_vma_private_data(vma) &
288 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
290 VM_BUG_ON(!is_vm_hugetlb_page(vma));
291 VM_BUG_ON(vma->vm_flags & VM_SHARED);
293 set_vma_private_data(vma, (get_vma_private_data(vma) &
294 HPAGE_RESV_MASK) | (unsigned long)map);
297 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
299 VM_BUG_ON(!is_vm_hugetlb_page(vma));
300 VM_BUG_ON(vma->vm_flags & VM_SHARED);
302 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
305 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
307 VM_BUG_ON(!is_vm_hugetlb_page(vma));
309 return (get_vma_private_data(vma) & flag) != 0;
312 /* Decrement the reserved pages in the hugepage pool by one */
313 static void decrement_hugepage_resv_vma(struct hstate *h,
314 struct vm_area_struct *vma)
316 if (vma->vm_flags & VM_NORESERVE)
319 if (vma->vm_flags & VM_SHARED) {
320 /* Shared mappings always use reserves */
321 h->resv_huge_pages--;
322 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
324 * Only the process that called mmap() has reserves for
327 h->resv_huge_pages--;
331 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
332 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
334 VM_BUG_ON(!is_vm_hugetlb_page(vma));
335 if (!(vma->vm_flags & VM_SHARED))
336 vma->vm_private_data = (void *)0;
339 /* Returns true if the VMA has associated reserve pages */
340 static int vma_has_private_reserves(struct vm_area_struct *vma)
342 if (vma->vm_flags & VM_SHARED)
344 if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER))
349 static void clear_huge_page(struct page *page,
350 unsigned long addr, unsigned long sz)
355 for (i = 0; i < sz/PAGE_SIZE; i++) {
357 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
361 static void copy_huge_page(struct page *dst, struct page *src,
362 unsigned long addr, struct vm_area_struct *vma)
365 struct hstate *h = hstate_vma(vma);
368 for (i = 0; i < pages_per_huge_page(h); i++) {
370 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
374 static void enqueue_huge_page(struct hstate *h, struct page *page)
376 int nid = page_to_nid(page);
377 list_add(&page->lru, &h->hugepage_freelists[nid]);
378 h->free_huge_pages++;
379 h->free_huge_pages_node[nid]++;
382 static struct page *dequeue_huge_page(struct hstate *h)
385 struct page *page = NULL;
387 for (nid = 0; nid < MAX_NUMNODES; ++nid) {
388 if (!list_empty(&h->hugepage_freelists[nid])) {
389 page = list_entry(h->hugepage_freelists[nid].next,
391 list_del(&page->lru);
392 h->free_huge_pages--;
393 h->free_huge_pages_node[nid]--;
400 static struct page *dequeue_huge_page_vma(struct hstate *h,
401 struct vm_area_struct *vma,
402 unsigned long address, int avoid_reserve)
405 struct page *page = NULL;
406 struct mempolicy *mpol;
407 nodemask_t *nodemask;
408 struct zonelist *zonelist = huge_zonelist(vma, address,
409 htlb_alloc_mask, &mpol, &nodemask);
414 * A child process with MAP_PRIVATE mappings created by their parent
415 * have no page reserves. This check ensures that reservations are
416 * not "stolen". The child may still get SIGKILLed
418 if (!vma_has_private_reserves(vma) &&
419 h->free_huge_pages - h->resv_huge_pages == 0)
422 /* If reserves cannot be used, ensure enough pages are in the pool */
423 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
426 for_each_zone_zonelist_nodemask(zone, z, zonelist,
427 MAX_NR_ZONES - 1, nodemask) {
428 nid = zone_to_nid(zone);
429 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
430 !list_empty(&h->hugepage_freelists[nid])) {
431 page = list_entry(h->hugepage_freelists[nid].next,
433 list_del(&page->lru);
434 h->free_huge_pages--;
435 h->free_huge_pages_node[nid]--;
438 decrement_hugepage_resv_vma(h, vma);
447 static void update_and_free_page(struct hstate *h, struct page *page)
452 h->nr_huge_pages_node[page_to_nid(page)]--;
453 for (i = 0; i < pages_per_huge_page(h); i++) {
454 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
455 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
456 1 << PG_private | 1<< PG_writeback);
458 set_compound_page_dtor(page, NULL);
459 set_page_refcounted(page);
460 arch_release_hugepage(page);
461 __free_pages(page, huge_page_order(h));
464 struct hstate *size_to_hstate(unsigned long size)
469 if (huge_page_size(h) == size)
475 static void free_huge_page(struct page *page)
478 * Can't pass hstate in here because it is called from the
479 * compound page destructor.
481 struct hstate *h = page_hstate(page);
482 int nid = page_to_nid(page);
483 struct address_space *mapping;
485 mapping = (struct address_space *) page_private(page);
486 set_page_private(page, 0);
487 BUG_ON(page_count(page));
488 INIT_LIST_HEAD(&page->lru);
490 spin_lock(&hugetlb_lock);
491 if (h->surplus_huge_pages_node[nid]) {
492 update_and_free_page(h, page);
493 h->surplus_huge_pages--;
494 h->surplus_huge_pages_node[nid]--;
496 enqueue_huge_page(h, page);
498 spin_unlock(&hugetlb_lock);
500 hugetlb_put_quota(mapping, 1);
504 * Increment or decrement surplus_huge_pages. Keep node-specific counters
505 * balanced by operating on them in a round-robin fashion.
506 * Returns 1 if an adjustment was made.
508 static int adjust_pool_surplus(struct hstate *h, int delta)
514 VM_BUG_ON(delta != -1 && delta != 1);
516 nid = next_node(nid, node_online_map);
517 if (nid == MAX_NUMNODES)
518 nid = first_node(node_online_map);
520 /* To shrink on this node, there must be a surplus page */
521 if (delta < 0 && !h->surplus_huge_pages_node[nid])
523 /* Surplus cannot exceed the total number of pages */
524 if (delta > 0 && h->surplus_huge_pages_node[nid] >=
525 h->nr_huge_pages_node[nid])
528 h->surplus_huge_pages += delta;
529 h->surplus_huge_pages_node[nid] += delta;
532 } while (nid != prev_nid);
538 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
540 set_compound_page_dtor(page, free_huge_page);
541 spin_lock(&hugetlb_lock);
543 h->nr_huge_pages_node[nid]++;
544 spin_unlock(&hugetlb_lock);
545 put_page(page); /* free it into the hugepage allocator */
548 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
552 page = alloc_pages_node(nid,
553 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
554 __GFP_REPEAT|__GFP_NOWARN,
557 if (arch_prepare_hugepage(page)) {
558 __free_pages(page, HUGETLB_PAGE_ORDER);
561 prep_new_huge_page(h, page, nid);
567 static int alloc_fresh_huge_page(struct hstate *h)
574 start_nid = h->hugetlb_next_nid;
577 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid);
581 * Use a helper variable to find the next node and then
582 * copy it back to hugetlb_next_nid afterwards:
583 * otherwise there's a window in which a racer might
584 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
585 * But we don't need to use a spin_lock here: it really
586 * doesn't matter if occasionally a racer chooses the
587 * same nid as we do. Move nid forward in the mask even
588 * if we just successfully allocated a hugepage so that
589 * the next caller gets hugepages on the next node.
591 next_nid = next_node(h->hugetlb_next_nid, node_online_map);
592 if (next_nid == MAX_NUMNODES)
593 next_nid = first_node(node_online_map);
594 h->hugetlb_next_nid = next_nid;
595 } while (!page && h->hugetlb_next_nid != start_nid);
598 count_vm_event(HTLB_BUDDY_PGALLOC);
600 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
605 static struct page *alloc_buddy_huge_page(struct hstate *h,
606 struct vm_area_struct *vma, unsigned long address)
612 * Assume we will successfully allocate the surplus page to
613 * prevent racing processes from causing the surplus to exceed
616 * This however introduces a different race, where a process B
617 * tries to grow the static hugepage pool while alloc_pages() is
618 * called by process A. B will only examine the per-node
619 * counters in determining if surplus huge pages can be
620 * converted to normal huge pages in adjust_pool_surplus(). A
621 * won't be able to increment the per-node counter, until the
622 * lock is dropped by B, but B doesn't drop hugetlb_lock until
623 * no more huge pages can be converted from surplus to normal
624 * state (and doesn't try to convert again). Thus, we have a
625 * case where a surplus huge page exists, the pool is grown, and
626 * the surplus huge page still exists after, even though it
627 * should just have been converted to a normal huge page. This
628 * does not leak memory, though, as the hugepage will be freed
629 * once it is out of use. It also does not allow the counters to
630 * go out of whack in adjust_pool_surplus() as we don't modify
631 * the node values until we've gotten the hugepage and only the
632 * per-node value is checked there.
634 spin_lock(&hugetlb_lock);
635 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
636 spin_unlock(&hugetlb_lock);
640 h->surplus_huge_pages++;
642 spin_unlock(&hugetlb_lock);
644 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
645 __GFP_REPEAT|__GFP_NOWARN,
648 spin_lock(&hugetlb_lock);
651 * This page is now managed by the hugetlb allocator and has
652 * no users -- drop the buddy allocator's reference.
654 put_page_testzero(page);
655 VM_BUG_ON(page_count(page));
656 nid = page_to_nid(page);
657 set_compound_page_dtor(page, free_huge_page);
659 * We incremented the global counters already
661 h->nr_huge_pages_node[nid]++;
662 h->surplus_huge_pages_node[nid]++;
663 __count_vm_event(HTLB_BUDDY_PGALLOC);
666 h->surplus_huge_pages--;
667 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
669 spin_unlock(&hugetlb_lock);
675 * Increase the hugetlb pool such that it can accomodate a reservation
678 static int gather_surplus_pages(struct hstate *h, int delta)
680 struct list_head surplus_list;
681 struct page *page, *tmp;
683 int needed, allocated;
685 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
687 h->resv_huge_pages += delta;
692 INIT_LIST_HEAD(&surplus_list);
696 spin_unlock(&hugetlb_lock);
697 for (i = 0; i < needed; i++) {
698 page = alloc_buddy_huge_page(h, NULL, 0);
701 * We were not able to allocate enough pages to
702 * satisfy the entire reservation so we free what
703 * we've allocated so far.
705 spin_lock(&hugetlb_lock);
710 list_add(&page->lru, &surplus_list);
715 * After retaking hugetlb_lock, we need to recalculate 'needed'
716 * because either resv_huge_pages or free_huge_pages may have changed.
718 spin_lock(&hugetlb_lock);
719 needed = (h->resv_huge_pages + delta) -
720 (h->free_huge_pages + allocated);
725 * The surplus_list now contains _at_least_ the number of extra pages
726 * needed to accomodate the reservation. Add the appropriate number
727 * of pages to the hugetlb pool and free the extras back to the buddy
728 * allocator. Commit the entire reservation here to prevent another
729 * process from stealing the pages as they are added to the pool but
730 * before they are reserved.
733 h->resv_huge_pages += delta;
736 /* Free the needed pages to the hugetlb pool */
737 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
740 list_del(&page->lru);
741 enqueue_huge_page(h, page);
744 /* Free unnecessary surplus pages to the buddy allocator */
745 if (!list_empty(&surplus_list)) {
746 spin_unlock(&hugetlb_lock);
747 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
748 list_del(&page->lru);
750 * The page has a reference count of zero already, so
751 * call free_huge_page directly instead of using
752 * put_page. This must be done with hugetlb_lock
753 * unlocked which is safe because free_huge_page takes
754 * hugetlb_lock before deciding how to free the page.
756 free_huge_page(page);
758 spin_lock(&hugetlb_lock);
765 * When releasing a hugetlb pool reservation, any surplus pages that were
766 * allocated to satisfy the reservation must be explicitly freed if they were
769 static void return_unused_surplus_pages(struct hstate *h,
770 unsigned long unused_resv_pages)
774 unsigned long nr_pages;
777 * We want to release as many surplus pages as possible, spread
778 * evenly across all nodes. Iterate across all nodes until we
779 * can no longer free unreserved surplus pages. This occurs when
780 * the nodes with surplus pages have no free pages.
782 unsigned long remaining_iterations = num_online_nodes();
784 /* Uncommit the reservation */
785 h->resv_huge_pages -= unused_resv_pages;
787 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
789 while (remaining_iterations-- && nr_pages) {
790 nid = next_node(nid, node_online_map);
791 if (nid == MAX_NUMNODES)
792 nid = first_node(node_online_map);
794 if (!h->surplus_huge_pages_node[nid])
797 if (!list_empty(&h->hugepage_freelists[nid])) {
798 page = list_entry(h->hugepage_freelists[nid].next,
800 list_del(&page->lru);
801 update_and_free_page(h, page);
802 h->free_huge_pages--;
803 h->free_huge_pages_node[nid]--;
804 h->surplus_huge_pages--;
805 h->surplus_huge_pages_node[nid]--;
807 remaining_iterations = num_online_nodes();
813 * Determine if the huge page at addr within the vma has an associated
814 * reservation. Where it does not we will need to logically increase
815 * reservation and actually increase quota before an allocation can occur.
816 * Where any new reservation would be required the reservation change is
817 * prepared, but not committed. Once the page has been quota'd allocated
818 * an instantiated the change should be committed via vma_commit_reservation.
819 * No action is required on failure.
821 static int vma_needs_reservation(struct hstate *h,
822 struct vm_area_struct *vma, unsigned long addr)
824 struct address_space *mapping = vma->vm_file->f_mapping;
825 struct inode *inode = mapping->host;
827 if (vma->vm_flags & VM_SHARED) {
828 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
829 return region_chg(&inode->i_mapping->private_list,
832 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
837 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
838 struct resv_map *reservations = vma_resv_map(vma);
840 err = region_chg(&reservations->regions, idx, idx + 1);
846 static void vma_commit_reservation(struct hstate *h,
847 struct vm_area_struct *vma, unsigned long addr)
849 struct address_space *mapping = vma->vm_file->f_mapping;
850 struct inode *inode = mapping->host;
852 if (vma->vm_flags & VM_SHARED) {
853 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
854 region_add(&inode->i_mapping->private_list, idx, idx + 1);
856 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
857 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
858 struct resv_map *reservations = vma_resv_map(vma);
860 /* Mark this page used in the map. */
861 region_add(&reservations->regions, idx, idx + 1);
865 static struct page *alloc_huge_page(struct vm_area_struct *vma,
866 unsigned long addr, int avoid_reserve)
868 struct hstate *h = hstate_vma(vma);
870 struct address_space *mapping = vma->vm_file->f_mapping;
871 struct inode *inode = mapping->host;
875 * Processes that did not create the mapping will have no reserves and
876 * will not have accounted against quota. Check that the quota can be
877 * made before satisfying the allocation
878 * MAP_NORESERVE mappings may also need pages and quota allocated
879 * if no reserve mapping overlaps.
881 chg = vma_needs_reservation(h, vma, addr);
885 if (hugetlb_get_quota(inode->i_mapping, chg))
886 return ERR_PTR(-ENOSPC);
888 spin_lock(&hugetlb_lock);
889 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
890 spin_unlock(&hugetlb_lock);
893 page = alloc_buddy_huge_page(h, vma, addr);
895 hugetlb_put_quota(inode->i_mapping, chg);
896 return ERR_PTR(-VM_FAULT_OOM);
900 set_page_refcounted(page);
901 set_page_private(page, (unsigned long) mapping);
903 vma_commit_reservation(h, vma, addr);
908 static void __init hugetlb_init_one_hstate(struct hstate *h)
912 for (i = 0; i < MAX_NUMNODES; ++i)
913 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
915 h->hugetlb_next_nid = first_node(node_online_map);
917 for (i = 0; i < h->max_huge_pages; ++i) {
918 if (!alloc_fresh_huge_page(h))
921 h->max_huge_pages = h->free_huge_pages = h->nr_huge_pages = i;
924 static void __init hugetlb_init_hstates(void)
929 hugetlb_init_one_hstate(h);
933 static void __init report_hugepages(void)
938 printk(KERN_INFO "Total HugeTLB memory allocated, "
941 1 << (h->order + PAGE_SHIFT - 20));
945 static int __init hugetlb_init(void)
947 BUILD_BUG_ON(HPAGE_SHIFT == 0);
949 if (!size_to_hstate(HPAGE_SIZE)) {
950 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
951 parsed_hstate->max_huge_pages = default_hstate_max_huge_pages;
953 default_hstate_idx = size_to_hstate(HPAGE_SIZE) - hstates;
955 hugetlb_init_hstates();
961 module_init(hugetlb_init);
963 /* Should be called on processing a hugepagesz=... option */
964 void __init hugetlb_add_hstate(unsigned order)
967 if (size_to_hstate(PAGE_SIZE << order)) {
968 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
971 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
973 h = &hstates[max_hstate++];
975 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
976 hugetlb_init_one_hstate(h);
980 static int __init hugetlb_setup(char *s)
985 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
986 * so this hugepages= parameter goes to the "default hstate".
989 mhp = &default_hstate_max_huge_pages;
991 mhp = &parsed_hstate->max_huge_pages;
993 if (sscanf(s, "%lu", mhp) <= 0)
998 __setup("hugepages=", hugetlb_setup);
1000 static unsigned int cpuset_mems_nr(unsigned int *array)
1003 unsigned int nr = 0;
1005 for_each_node_mask(node, cpuset_current_mems_allowed)
1011 #ifdef CONFIG_SYSCTL
1012 #ifdef CONFIG_HIGHMEM
1013 static void try_to_free_low(struct hstate *h, unsigned long count)
1017 for (i = 0; i < MAX_NUMNODES; ++i) {
1018 struct page *page, *next;
1019 struct list_head *freel = &h->hugepage_freelists[i];
1020 list_for_each_entry_safe(page, next, freel, lru) {
1021 if (count >= h->nr_huge_pages)
1023 if (PageHighMem(page))
1025 list_del(&page->lru);
1026 update_and_free_page(h, page);
1027 h->free_huge_pages--;
1028 h->free_huge_pages_node[page_to_nid(page)]--;
1033 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1038 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1039 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1041 unsigned long min_count, ret;
1044 * Increase the pool size
1045 * First take pages out of surplus state. Then make up the
1046 * remaining difference by allocating fresh huge pages.
1048 * We might race with alloc_buddy_huge_page() here and be unable
1049 * to convert a surplus huge page to a normal huge page. That is
1050 * not critical, though, it just means the overall size of the
1051 * pool might be one hugepage larger than it needs to be, but
1052 * within all the constraints specified by the sysctls.
1054 spin_lock(&hugetlb_lock);
1055 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1056 if (!adjust_pool_surplus(h, -1))
1060 while (count > persistent_huge_pages(h)) {
1062 * If this allocation races such that we no longer need the
1063 * page, free_huge_page will handle it by freeing the page
1064 * and reducing the surplus.
1066 spin_unlock(&hugetlb_lock);
1067 ret = alloc_fresh_huge_page(h);
1068 spin_lock(&hugetlb_lock);
1075 * Decrease the pool size
1076 * First return free pages to the buddy allocator (being careful
1077 * to keep enough around to satisfy reservations). Then place
1078 * pages into surplus state as needed so the pool will shrink
1079 * to the desired size as pages become free.
1081 * By placing pages into the surplus state independent of the
1082 * overcommit value, we are allowing the surplus pool size to
1083 * exceed overcommit. There are few sane options here. Since
1084 * alloc_buddy_huge_page() is checking the global counter,
1085 * though, we'll note that we're not allowed to exceed surplus
1086 * and won't grow the pool anywhere else. Not until one of the
1087 * sysctls are changed, or the surplus pages go out of use.
1089 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1090 min_count = max(count, min_count);
1091 try_to_free_low(h, min_count);
1092 while (min_count < persistent_huge_pages(h)) {
1093 struct page *page = dequeue_huge_page(h);
1096 update_and_free_page(h, page);
1098 while (count < persistent_huge_pages(h)) {
1099 if (!adjust_pool_surplus(h, 1))
1103 ret = persistent_huge_pages(h);
1104 spin_unlock(&hugetlb_lock);
1108 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1109 struct file *file, void __user *buffer,
1110 size_t *length, loff_t *ppos)
1112 struct hstate *h = &default_hstate;
1116 tmp = h->max_huge_pages;
1119 table->maxlen = sizeof(unsigned long);
1120 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1123 h->max_huge_pages = set_max_huge_pages(h, tmp);
1128 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1129 struct file *file, void __user *buffer,
1130 size_t *length, loff_t *ppos)
1132 proc_dointvec(table, write, file, buffer, length, ppos);
1133 if (hugepages_treat_as_movable)
1134 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1136 htlb_alloc_mask = GFP_HIGHUSER;
1140 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1141 struct file *file, void __user *buffer,
1142 size_t *length, loff_t *ppos)
1144 struct hstate *h = &default_hstate;
1148 tmp = h->nr_overcommit_huge_pages;
1151 table->maxlen = sizeof(unsigned long);
1152 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1155 spin_lock(&hugetlb_lock);
1156 h->nr_overcommit_huge_pages = tmp;
1157 spin_unlock(&hugetlb_lock);
1163 #endif /* CONFIG_SYSCTL */
1165 int hugetlb_report_meminfo(char *buf)
1167 struct hstate *h = &default_hstate;
1169 "HugePages_Total: %5lu\n"
1170 "HugePages_Free: %5lu\n"
1171 "HugePages_Rsvd: %5lu\n"
1172 "HugePages_Surp: %5lu\n"
1173 "Hugepagesize: %5lu kB\n",
1177 h->surplus_huge_pages,
1178 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1181 int hugetlb_report_node_meminfo(int nid, char *buf)
1183 struct hstate *h = &default_hstate;
1185 "Node %d HugePages_Total: %5u\n"
1186 "Node %d HugePages_Free: %5u\n"
1187 "Node %d HugePages_Surp: %5u\n",
1188 nid, h->nr_huge_pages_node[nid],
1189 nid, h->free_huge_pages_node[nid],
1190 nid, h->surplus_huge_pages_node[nid]);
1193 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1194 unsigned long hugetlb_total_pages(void)
1196 struct hstate *h = &default_hstate;
1197 return h->nr_huge_pages * pages_per_huge_page(h);
1200 static int hugetlb_acct_memory(struct hstate *h, long delta)
1204 spin_lock(&hugetlb_lock);
1206 * When cpuset is configured, it breaks the strict hugetlb page
1207 * reservation as the accounting is done on a global variable. Such
1208 * reservation is completely rubbish in the presence of cpuset because
1209 * the reservation is not checked against page availability for the
1210 * current cpuset. Application can still potentially OOM'ed by kernel
1211 * with lack of free htlb page in cpuset that the task is in.
1212 * Attempt to enforce strict accounting with cpuset is almost
1213 * impossible (or too ugly) because cpuset is too fluid that
1214 * task or memory node can be dynamically moved between cpusets.
1216 * The change of semantics for shared hugetlb mapping with cpuset is
1217 * undesirable. However, in order to preserve some of the semantics,
1218 * we fall back to check against current free page availability as
1219 * a best attempt and hopefully to minimize the impact of changing
1220 * semantics that cpuset has.
1223 if (gather_surplus_pages(h, delta) < 0)
1226 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1227 return_unused_surplus_pages(h, delta);
1234 return_unused_surplus_pages(h, (unsigned long) -delta);
1237 spin_unlock(&hugetlb_lock);
1241 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1243 struct resv_map *reservations = vma_resv_map(vma);
1246 * This new VMA should share its siblings reservation map if present.
1247 * The VMA will only ever have a valid reservation map pointer where
1248 * it is being copied for another still existing VMA. As that VMA
1249 * has a reference to the reservation map it cannot dissappear until
1250 * after this open call completes. It is therefore safe to take a
1251 * new reference here without additional locking.
1254 kref_get(&reservations->refs);
1257 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1259 struct hstate *h = hstate_vma(vma);
1260 struct resv_map *reservations = vma_resv_map(vma);
1261 unsigned long reserve;
1262 unsigned long start;
1266 start = vma_hugecache_offset(h, vma, vma->vm_start);
1267 end = vma_hugecache_offset(h, vma, vma->vm_end);
1269 reserve = (end - start) -
1270 region_count(&reservations->regions, start, end);
1272 kref_put(&reservations->refs, resv_map_release);
1275 hugetlb_acct_memory(h, -reserve);
1280 * We cannot handle pagefaults against hugetlb pages at all. They cause
1281 * handle_mm_fault() to try to instantiate regular-sized pages in the
1282 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1285 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1291 struct vm_operations_struct hugetlb_vm_ops = {
1292 .fault = hugetlb_vm_op_fault,
1293 .open = hugetlb_vm_op_open,
1294 .close = hugetlb_vm_op_close,
1297 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1304 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1306 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1308 entry = pte_mkyoung(entry);
1309 entry = pte_mkhuge(entry);
1314 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1315 unsigned long address, pte_t *ptep)
1319 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1320 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1321 update_mmu_cache(vma, address, entry);
1326 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1327 struct vm_area_struct *vma)
1329 pte_t *src_pte, *dst_pte, entry;
1330 struct page *ptepage;
1333 struct hstate *h = hstate_vma(vma);
1334 unsigned long sz = huge_page_size(h);
1336 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1338 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1339 src_pte = huge_pte_offset(src, addr);
1342 dst_pte = huge_pte_alloc(dst, addr, sz);
1346 /* If the pagetables are shared don't copy or take references */
1347 if (dst_pte == src_pte)
1350 spin_lock(&dst->page_table_lock);
1351 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1352 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1354 huge_ptep_set_wrprotect(src, addr, src_pte);
1355 entry = huge_ptep_get(src_pte);
1356 ptepage = pte_page(entry);
1358 set_huge_pte_at(dst, addr, dst_pte, entry);
1360 spin_unlock(&src->page_table_lock);
1361 spin_unlock(&dst->page_table_lock);
1369 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1370 unsigned long end, struct page *ref_page)
1372 struct mm_struct *mm = vma->vm_mm;
1373 unsigned long address;
1378 struct hstate *h = hstate_vma(vma);
1379 unsigned long sz = huge_page_size(h);
1382 * A page gathering list, protected by per file i_mmap_lock. The
1383 * lock is used to avoid list corruption from multiple unmapping
1384 * of the same page since we are using page->lru.
1386 LIST_HEAD(page_list);
1388 WARN_ON(!is_vm_hugetlb_page(vma));
1389 BUG_ON(start & ~huge_page_mask(h));
1390 BUG_ON(end & ~huge_page_mask(h));
1392 spin_lock(&mm->page_table_lock);
1393 for (address = start; address < end; address += sz) {
1394 ptep = huge_pte_offset(mm, address);
1398 if (huge_pmd_unshare(mm, &address, ptep))
1402 * If a reference page is supplied, it is because a specific
1403 * page is being unmapped, not a range. Ensure the page we
1404 * are about to unmap is the actual page of interest.
1407 pte = huge_ptep_get(ptep);
1408 if (huge_pte_none(pte))
1410 page = pte_page(pte);
1411 if (page != ref_page)
1415 * Mark the VMA as having unmapped its page so that
1416 * future faults in this VMA will fail rather than
1417 * looking like data was lost
1419 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1422 pte = huge_ptep_get_and_clear(mm, address, ptep);
1423 if (huge_pte_none(pte))
1426 page = pte_page(pte);
1428 set_page_dirty(page);
1429 list_add(&page->lru, &page_list);
1431 spin_unlock(&mm->page_table_lock);
1432 flush_tlb_range(vma, start, end);
1433 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1434 list_del(&page->lru);
1439 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1440 unsigned long end, struct page *ref_page)
1443 * It is undesirable to test vma->vm_file as it should be non-null
1444 * for valid hugetlb area. However, vm_file will be NULL in the error
1445 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
1446 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
1447 * to clean up. Since no pte has actually been setup, it is safe to
1448 * do nothing in this case.
1451 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1452 __unmap_hugepage_range(vma, start, end, ref_page);
1453 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1458 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1459 * mappping it owns the reserve page for. The intention is to unmap the page
1460 * from other VMAs and let the children be SIGKILLed if they are faulting the
1463 int unmap_ref_private(struct mm_struct *mm,
1464 struct vm_area_struct *vma,
1466 unsigned long address)
1468 struct vm_area_struct *iter_vma;
1469 struct address_space *mapping;
1470 struct prio_tree_iter iter;
1474 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1475 * from page cache lookup which is in HPAGE_SIZE units.
1477 address = address & huge_page_mask(hstate_vma(vma));
1478 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1479 + (vma->vm_pgoff >> PAGE_SHIFT);
1480 mapping = (struct address_space *)page_private(page);
1482 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1483 /* Do not unmap the current VMA */
1484 if (iter_vma == vma)
1488 * Unmap the page from other VMAs without their own reserves.
1489 * They get marked to be SIGKILLed if they fault in these
1490 * areas. This is because a future no-page fault on this VMA
1491 * could insert a zeroed page instead of the data existing
1492 * from the time of fork. This would look like data corruption
1494 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1495 unmap_hugepage_range(iter_vma,
1496 address, address + HPAGE_SIZE,
1503 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1504 unsigned long address, pte_t *ptep, pte_t pte,
1505 struct page *pagecache_page)
1507 struct hstate *h = hstate_vma(vma);
1508 struct page *old_page, *new_page;
1510 int outside_reserve = 0;
1512 old_page = pte_page(pte);
1515 /* If no-one else is actually using this page, avoid the copy
1516 * and just make the page writable */
1517 avoidcopy = (page_count(old_page) == 1);
1519 set_huge_ptep_writable(vma, address, ptep);
1524 * If the process that created a MAP_PRIVATE mapping is about to
1525 * perform a COW due to a shared page count, attempt to satisfy
1526 * the allocation without using the existing reserves. The pagecache
1527 * page is used to determine if the reserve at this address was
1528 * consumed or not. If reserves were used, a partial faulted mapping
1529 * at the time of fork() could consume its reserves on COW instead
1530 * of the full address range.
1532 if (!(vma->vm_flags & VM_SHARED) &&
1533 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1534 old_page != pagecache_page)
1535 outside_reserve = 1;
1537 page_cache_get(old_page);
1538 new_page = alloc_huge_page(vma, address, outside_reserve);
1540 if (IS_ERR(new_page)) {
1541 page_cache_release(old_page);
1544 * If a process owning a MAP_PRIVATE mapping fails to COW,
1545 * it is due to references held by a child and an insufficient
1546 * huge page pool. To guarantee the original mappers
1547 * reliability, unmap the page from child processes. The child
1548 * may get SIGKILLed if it later faults.
1550 if (outside_reserve) {
1551 BUG_ON(huge_pte_none(pte));
1552 if (unmap_ref_private(mm, vma, old_page, address)) {
1553 BUG_ON(page_count(old_page) != 1);
1554 BUG_ON(huge_pte_none(pte));
1555 goto retry_avoidcopy;
1560 return -PTR_ERR(new_page);
1563 spin_unlock(&mm->page_table_lock);
1564 copy_huge_page(new_page, old_page, address, vma);
1565 __SetPageUptodate(new_page);
1566 spin_lock(&mm->page_table_lock);
1568 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
1569 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
1571 huge_ptep_clear_flush(vma, address, ptep);
1572 set_huge_pte_at(mm, address, ptep,
1573 make_huge_pte(vma, new_page, 1));
1574 /* Make the old page be freed below */
1575 new_page = old_page;
1577 page_cache_release(new_page);
1578 page_cache_release(old_page);
1582 /* Return the pagecache page at a given address within a VMA */
1583 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
1584 struct vm_area_struct *vma, unsigned long address)
1586 struct address_space *mapping;
1589 mapping = vma->vm_file->f_mapping;
1590 idx = vma_hugecache_offset(h, vma, address);
1592 return find_lock_page(mapping, idx);
1595 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1596 unsigned long address, pte_t *ptep, int write_access)
1598 struct hstate *h = hstate_vma(vma);
1599 int ret = VM_FAULT_SIGBUS;
1603 struct address_space *mapping;
1607 * Currently, we are forced to kill the process in the event the
1608 * original mapper has unmapped pages from the child due to a failed
1609 * COW. Warn that such a situation has occured as it may not be obvious
1611 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
1613 "PID %d killed due to inadequate hugepage pool\n",
1618 mapping = vma->vm_file->f_mapping;
1619 idx = vma_hugecache_offset(h, vma, address);
1622 * Use page lock to guard against racing truncation
1623 * before we get page_table_lock.
1626 page = find_lock_page(mapping, idx);
1628 size = i_size_read(mapping->host) >> huge_page_shift(h);
1631 page = alloc_huge_page(vma, address, 0);
1633 ret = -PTR_ERR(page);
1636 clear_huge_page(page, address, huge_page_size(h));
1637 __SetPageUptodate(page);
1639 if (vma->vm_flags & VM_SHARED) {
1641 struct inode *inode = mapping->host;
1643 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
1651 spin_lock(&inode->i_lock);
1652 inode->i_blocks += blocks_per_huge_page(h);
1653 spin_unlock(&inode->i_lock);
1658 spin_lock(&mm->page_table_lock);
1659 size = i_size_read(mapping->host) >> huge_page_shift(h);
1664 if (!huge_pte_none(huge_ptep_get(ptep)))
1667 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
1668 && (vma->vm_flags & VM_SHARED)));
1669 set_huge_pte_at(mm, address, ptep, new_pte);
1671 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1672 /* Optimization, do the COW without a second fault */
1673 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
1676 spin_unlock(&mm->page_table_lock);
1682 spin_unlock(&mm->page_table_lock);
1688 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1689 unsigned long address, int write_access)
1694 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
1695 struct hstate *h = hstate_vma(vma);
1697 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
1699 return VM_FAULT_OOM;
1702 * Serialize hugepage allocation and instantiation, so that we don't
1703 * get spurious allocation failures if two CPUs race to instantiate
1704 * the same page in the page cache.
1706 mutex_lock(&hugetlb_instantiation_mutex);
1707 entry = huge_ptep_get(ptep);
1708 if (huge_pte_none(entry)) {
1709 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
1710 mutex_unlock(&hugetlb_instantiation_mutex);
1716 spin_lock(&mm->page_table_lock);
1717 /* Check for a racing update before calling hugetlb_cow */
1718 if (likely(pte_same(entry, huge_ptep_get(ptep))))
1719 if (write_access && !pte_write(entry)) {
1721 page = hugetlbfs_pagecache_page(h, vma, address);
1722 ret = hugetlb_cow(mm, vma, address, ptep, entry, page);
1728 spin_unlock(&mm->page_table_lock);
1729 mutex_unlock(&hugetlb_instantiation_mutex);
1734 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
1735 struct page **pages, struct vm_area_struct **vmas,
1736 unsigned long *position, int *length, int i,
1739 unsigned long pfn_offset;
1740 unsigned long vaddr = *position;
1741 int remainder = *length;
1742 struct hstate *h = hstate_vma(vma);
1744 spin_lock(&mm->page_table_lock);
1745 while (vaddr < vma->vm_end && remainder) {
1750 * Some archs (sparc64, sh*) have multiple pte_ts to
1751 * each hugepage. We have to make * sure we get the
1752 * first, for the page indexing below to work.
1754 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
1756 if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
1757 (write && !pte_write(huge_ptep_get(pte)))) {
1760 spin_unlock(&mm->page_table_lock);
1761 ret = hugetlb_fault(mm, vma, vaddr, write);
1762 spin_lock(&mm->page_table_lock);
1763 if (!(ret & VM_FAULT_ERROR))
1772 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
1773 page = pte_page(huge_ptep_get(pte));
1777 pages[i] = page + pfn_offset;
1787 if (vaddr < vma->vm_end && remainder &&
1788 pfn_offset < pages_per_huge_page(h)) {
1790 * We use pfn_offset to avoid touching the pageframes
1791 * of this compound page.
1796 spin_unlock(&mm->page_table_lock);
1797 *length = remainder;
1803 void hugetlb_change_protection(struct vm_area_struct *vma,
1804 unsigned long address, unsigned long end, pgprot_t newprot)
1806 struct mm_struct *mm = vma->vm_mm;
1807 unsigned long start = address;
1810 struct hstate *h = hstate_vma(vma);
1812 BUG_ON(address >= end);
1813 flush_cache_range(vma, address, end);
1815 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1816 spin_lock(&mm->page_table_lock);
1817 for (; address < end; address += huge_page_size(h)) {
1818 ptep = huge_pte_offset(mm, address);
1821 if (huge_pmd_unshare(mm, &address, ptep))
1823 if (!huge_pte_none(huge_ptep_get(ptep))) {
1824 pte = huge_ptep_get_and_clear(mm, address, ptep);
1825 pte = pte_mkhuge(pte_modify(pte, newprot));
1826 set_huge_pte_at(mm, address, ptep, pte);
1829 spin_unlock(&mm->page_table_lock);
1830 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1832 flush_tlb_range(vma, start, end);
1835 int hugetlb_reserve_pages(struct inode *inode,
1837 struct vm_area_struct *vma)
1840 struct hstate *h = hstate_inode(inode);
1842 if (vma && vma->vm_flags & VM_NORESERVE)
1846 * Shared mappings base their reservation on the number of pages that
1847 * are already allocated on behalf of the file. Private mappings need
1848 * to reserve the full area even if read-only as mprotect() may be
1849 * called to make the mapping read-write. Assume !vma is a shm mapping
1851 if (!vma || vma->vm_flags & VM_SHARED)
1852 chg = region_chg(&inode->i_mapping->private_list, from, to);
1854 struct resv_map *resv_map = resv_map_alloc();
1860 set_vma_resv_map(vma, resv_map);
1861 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
1867 if (hugetlb_get_quota(inode->i_mapping, chg))
1869 ret = hugetlb_acct_memory(h, chg);
1871 hugetlb_put_quota(inode->i_mapping, chg);
1874 if (!vma || vma->vm_flags & VM_SHARED)
1875 region_add(&inode->i_mapping->private_list, from, to);
1879 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1881 struct hstate *h = hstate_inode(inode);
1882 long chg = region_truncate(&inode->i_mapping->private_list, offset);
1884 spin_lock(&inode->i_lock);
1885 inode->i_blocks -= blocks_per_huge_page(h);
1886 spin_unlock(&inode->i_lock);
1888 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1889 hugetlb_acct_memory(h, -(chg - freed));