2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
26 #include <asm/pgtable.h>
29 #include <linux/hugetlb.h>
30 #include <linux/node.h>
33 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
34 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
35 unsigned long hugepages_treat_as_movable;
37 static int max_hstate;
38 unsigned int default_hstate_idx;
39 struct hstate hstates[HUGE_MAX_HSTATE];
41 __initdata LIST_HEAD(huge_boot_pages);
43 /* for command line parsing */
44 static struct hstate * __initdata parsed_hstate;
45 static unsigned long __initdata default_hstate_max_huge_pages;
46 static unsigned long __initdata default_hstate_size;
48 #define for_each_hstate(h) \
49 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
52 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
54 static DEFINE_SPINLOCK(hugetlb_lock);
57 * Region tracking -- allows tracking of reservations and instantiated pages
58 * across the pages in a mapping.
60 * The region data structures are protected by a combination of the mmap_sem
61 * and the hugetlb_instantion_mutex. To access or modify a region the caller
62 * must either hold the mmap_sem for write, or the mmap_sem for read and
63 * the hugetlb_instantiation mutex:
65 * down_write(&mm->mmap_sem);
67 * down_read(&mm->mmap_sem);
68 * mutex_lock(&hugetlb_instantiation_mutex);
71 struct list_head link;
76 static long region_add(struct list_head *head, long f, long t)
78 struct file_region *rg, *nrg, *trg;
80 /* Locate the region we are either in or before. */
81 list_for_each_entry(rg, head, link)
85 /* Round our left edge to the current segment if it encloses us. */
89 /* Check for and consume any regions we now overlap with. */
91 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
92 if (&rg->link == head)
97 /* If this area reaches higher then extend our area to
98 * include it completely. If this is not the first area
99 * which we intend to reuse, free it. */
112 static long region_chg(struct list_head *head, long f, long t)
114 struct file_region *rg, *nrg;
117 /* Locate the region we are before or in. */
118 list_for_each_entry(rg, head, link)
122 /* If we are below the current region then a new region is required.
123 * Subtle, allocate a new region at the position but make it zero
124 * size such that we can guarantee to record the reservation. */
125 if (&rg->link == head || t < rg->from) {
126 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
131 INIT_LIST_HEAD(&nrg->link);
132 list_add(&nrg->link, rg->link.prev);
137 /* Round our left edge to the current segment if it encloses us. */
142 /* Check for and consume any regions we now overlap with. */
143 list_for_each_entry(rg, rg->link.prev, link) {
144 if (&rg->link == head)
149 /* We overlap with this area, if it extends futher than
150 * us then we must extend ourselves. Account for its
151 * existing reservation. */
156 chg -= rg->to - rg->from;
161 static long region_truncate(struct list_head *head, long end)
163 struct file_region *rg, *trg;
166 /* Locate the region we are either in or before. */
167 list_for_each_entry(rg, head, link)
170 if (&rg->link == head)
173 /* If we are in the middle of a region then adjust it. */
174 if (end > rg->from) {
177 rg = list_entry(rg->link.next, typeof(*rg), link);
180 /* Drop any remaining regions. */
181 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
182 if (&rg->link == head)
184 chg += rg->to - rg->from;
191 static long region_count(struct list_head *head, long f, long t)
193 struct file_region *rg;
196 /* Locate each segment we overlap with, and count that overlap. */
197 list_for_each_entry(rg, head, link) {
206 seg_from = max(rg->from, f);
207 seg_to = min(rg->to, t);
209 chg += seg_to - seg_from;
216 * Convert the address within this vma to the page offset within
217 * the mapping, in pagecache page units; huge pages here.
219 static pgoff_t vma_hugecache_offset(struct hstate *h,
220 struct vm_area_struct *vma, unsigned long address)
222 return ((address - vma->vm_start) >> huge_page_shift(h)) +
223 (vma->vm_pgoff >> huge_page_order(h));
226 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
227 unsigned long address)
229 return vma_hugecache_offset(hstate_vma(vma), vma, address);
233 * Return the size of the pages allocated when backing a VMA. In the majority
234 * cases this will be same size as used by the page table entries.
236 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
238 struct hstate *hstate;
240 if (!is_vm_hugetlb_page(vma))
243 hstate = hstate_vma(vma);
245 return 1UL << (hstate->order + PAGE_SHIFT);
247 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
250 * Return the page size being used by the MMU to back a VMA. In the majority
251 * of cases, the page size used by the kernel matches the MMU size. On
252 * architectures where it differs, an architecture-specific version of this
253 * function is required.
255 #ifndef vma_mmu_pagesize
256 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
258 return vma_kernel_pagesize(vma);
263 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
264 * bits of the reservation map pointer, which are always clear due to
267 #define HPAGE_RESV_OWNER (1UL << 0)
268 #define HPAGE_RESV_UNMAPPED (1UL << 1)
269 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
272 * These helpers are used to track how many pages are reserved for
273 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
274 * is guaranteed to have their future faults succeed.
276 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
277 * the reserve counters are updated with the hugetlb_lock held. It is safe
278 * to reset the VMA at fork() time as it is not in use yet and there is no
279 * chance of the global counters getting corrupted as a result of the values.
281 * The private mapping reservation is represented in a subtly different
282 * manner to a shared mapping. A shared mapping has a region map associated
283 * with the underlying file, this region map represents the backing file
284 * pages which have ever had a reservation assigned which this persists even
285 * after the page is instantiated. A private mapping has a region map
286 * associated with the original mmap which is attached to all VMAs which
287 * reference it, this region map represents those offsets which have consumed
288 * reservation ie. where pages have been instantiated.
290 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
292 return (unsigned long)vma->vm_private_data;
295 static void set_vma_private_data(struct vm_area_struct *vma,
298 vma->vm_private_data = (void *)value;
303 struct list_head regions;
306 static struct resv_map *resv_map_alloc(void)
308 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
312 kref_init(&resv_map->refs);
313 INIT_LIST_HEAD(&resv_map->regions);
318 static void resv_map_release(struct kref *ref)
320 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
322 /* Clear out any active regions before we release the map. */
323 region_truncate(&resv_map->regions, 0);
327 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
329 VM_BUG_ON(!is_vm_hugetlb_page(vma));
330 if (!(vma->vm_flags & VM_MAYSHARE))
331 return (struct resv_map *)(get_vma_private_data(vma) &
336 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
338 VM_BUG_ON(!is_vm_hugetlb_page(vma));
339 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
341 set_vma_private_data(vma, (get_vma_private_data(vma) &
342 HPAGE_RESV_MASK) | (unsigned long)map);
345 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
347 VM_BUG_ON(!is_vm_hugetlb_page(vma));
348 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
350 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
353 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
355 VM_BUG_ON(!is_vm_hugetlb_page(vma));
357 return (get_vma_private_data(vma) & flag) != 0;
360 /* Decrement the reserved pages in the hugepage pool by one */
361 static void decrement_hugepage_resv_vma(struct hstate *h,
362 struct vm_area_struct *vma)
364 if (vma->vm_flags & VM_NORESERVE)
367 if (vma->vm_flags & VM_MAYSHARE) {
368 /* Shared mappings always use reserves */
369 h->resv_huge_pages--;
370 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
372 * Only the process that called mmap() has reserves for
375 h->resv_huge_pages--;
379 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
380 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
382 VM_BUG_ON(!is_vm_hugetlb_page(vma));
383 if (!(vma->vm_flags & VM_MAYSHARE))
384 vma->vm_private_data = (void *)0;
387 /* Returns true if the VMA has associated reserve pages */
388 static int vma_has_reserves(struct vm_area_struct *vma)
390 if (vma->vm_flags & VM_MAYSHARE)
392 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
397 static void clear_gigantic_page(struct page *page,
398 unsigned long addr, unsigned long sz)
401 struct page *p = page;
404 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
406 clear_user_highpage(p, addr + i * PAGE_SIZE);
409 static void clear_huge_page(struct page *page,
410 unsigned long addr, unsigned long sz)
414 if (unlikely(sz/PAGE_SIZE > MAX_ORDER_NR_PAGES)) {
415 clear_gigantic_page(page, addr, sz);
420 for (i = 0; i < sz/PAGE_SIZE; i++) {
422 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
426 static void copy_user_gigantic_page(struct page *dst, struct page *src,
427 unsigned long addr, struct vm_area_struct *vma)
430 struct hstate *h = hstate_vma(vma);
431 struct page *dst_base = dst;
432 struct page *src_base = src;
434 for (i = 0; i < pages_per_huge_page(h); ) {
436 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
439 dst = mem_map_next(dst, dst_base, i);
440 src = mem_map_next(src, src_base, i);
444 static void copy_user_huge_page(struct page *dst, struct page *src,
445 unsigned long addr, struct vm_area_struct *vma)
448 struct hstate *h = hstate_vma(vma);
450 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
451 copy_user_gigantic_page(dst, src, addr, vma);
456 for (i = 0; i < pages_per_huge_page(h); i++) {
458 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
462 static void copy_gigantic_page(struct page *dst, struct page *src)
465 struct hstate *h = page_hstate(src);
466 struct page *dst_base = dst;
467 struct page *src_base = src;
469 for (i = 0; i < pages_per_huge_page(h); ) {
471 copy_highpage(dst, src);
474 dst = mem_map_next(dst, dst_base, i);
475 src = mem_map_next(src, src_base, i);
479 void copy_huge_page(struct page *dst, struct page *src)
482 struct hstate *h = page_hstate(src);
484 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
485 copy_gigantic_page(dst, src);
490 for (i = 0; i < pages_per_huge_page(h); i++) {
492 copy_highpage(dst + i, src + i);
496 static void enqueue_huge_page(struct hstate *h, struct page *page)
498 int nid = page_to_nid(page);
499 list_add(&page->lru, &h->hugepage_freelists[nid]);
500 h->free_huge_pages++;
501 h->free_huge_pages_node[nid]++;
504 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
508 if (list_empty(&h->hugepage_freelists[nid]))
510 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
511 list_del(&page->lru);
512 h->free_huge_pages--;
513 h->free_huge_pages_node[nid]--;
517 static struct page *dequeue_huge_page_vma(struct hstate *h,
518 struct vm_area_struct *vma,
519 unsigned long address, int avoid_reserve)
521 struct page *page = NULL;
522 struct mempolicy *mpol;
523 nodemask_t *nodemask;
524 struct zonelist *zonelist;
529 zonelist = huge_zonelist(vma, address,
530 htlb_alloc_mask, &mpol, &nodemask);
532 * A child process with MAP_PRIVATE mappings created by their parent
533 * have no page reserves. This check ensures that reservations are
534 * not "stolen". The child may still get SIGKILLed
536 if (!vma_has_reserves(vma) &&
537 h->free_huge_pages - h->resv_huge_pages == 0)
540 /* If reserves cannot be used, ensure enough pages are in the pool */
541 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
544 for_each_zone_zonelist_nodemask(zone, z, zonelist,
545 MAX_NR_ZONES - 1, nodemask) {
546 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
547 page = dequeue_huge_page_node(h, zone_to_nid(zone));
550 decrement_hugepage_resv_vma(h, vma);
561 static void update_and_free_page(struct hstate *h, struct page *page)
565 VM_BUG_ON(h->order >= MAX_ORDER);
568 h->nr_huge_pages_node[page_to_nid(page)]--;
569 for (i = 0; i < pages_per_huge_page(h); i++) {
570 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
571 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
572 1 << PG_private | 1<< PG_writeback);
574 set_compound_page_dtor(page, NULL);
575 set_page_refcounted(page);
576 arch_release_hugepage(page);
577 __free_pages(page, huge_page_order(h));
580 struct hstate *size_to_hstate(unsigned long size)
585 if (huge_page_size(h) == size)
591 static void free_huge_page(struct page *page)
594 * Can't pass hstate in here because it is called from the
595 * compound page destructor.
597 struct hstate *h = page_hstate(page);
598 int nid = page_to_nid(page);
599 struct address_space *mapping;
601 mapping = (struct address_space *) page_private(page);
602 set_page_private(page, 0);
603 page->mapping = NULL;
604 BUG_ON(page_count(page));
605 BUG_ON(page_mapcount(page));
606 INIT_LIST_HEAD(&page->lru);
608 spin_lock(&hugetlb_lock);
609 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
610 update_and_free_page(h, page);
611 h->surplus_huge_pages--;
612 h->surplus_huge_pages_node[nid]--;
614 enqueue_huge_page(h, page);
616 spin_unlock(&hugetlb_lock);
618 hugetlb_put_quota(mapping, 1);
621 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
623 set_compound_page_dtor(page, free_huge_page);
624 spin_lock(&hugetlb_lock);
626 h->nr_huge_pages_node[nid]++;
627 spin_unlock(&hugetlb_lock);
628 put_page(page); /* free it into the hugepage allocator */
631 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
634 int nr_pages = 1 << order;
635 struct page *p = page + 1;
637 /* we rely on prep_new_huge_page to set the destructor */
638 set_compound_order(page, order);
640 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
642 p->first_page = page;
646 int PageHuge(struct page *page)
648 compound_page_dtor *dtor;
650 if (!PageCompound(page))
653 page = compound_head(page);
654 dtor = get_compound_page_dtor(page);
656 return dtor == free_huge_page;
659 EXPORT_SYMBOL_GPL(PageHuge);
661 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
665 if (h->order >= MAX_ORDER)
668 page = alloc_pages_exact_node(nid,
669 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
670 __GFP_REPEAT|__GFP_NOWARN,
673 if (arch_prepare_hugepage(page)) {
674 __free_pages(page, huge_page_order(h));
677 prep_new_huge_page(h, page, nid);
684 * common helper functions for hstate_next_node_to_{alloc|free}.
685 * We may have allocated or freed a huge page based on a different
686 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
687 * be outside of *nodes_allowed. Ensure that we use an allowed
688 * node for alloc or free.
690 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
692 nid = next_node(nid, *nodes_allowed);
693 if (nid == MAX_NUMNODES)
694 nid = first_node(*nodes_allowed);
695 VM_BUG_ON(nid >= MAX_NUMNODES);
700 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
702 if (!node_isset(nid, *nodes_allowed))
703 nid = next_node_allowed(nid, nodes_allowed);
708 * returns the previously saved node ["this node"] from which to
709 * allocate a persistent huge page for the pool and advance the
710 * next node from which to allocate, handling wrap at end of node
713 static int hstate_next_node_to_alloc(struct hstate *h,
714 nodemask_t *nodes_allowed)
718 VM_BUG_ON(!nodes_allowed);
720 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
721 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
726 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
733 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
734 next_nid = start_nid;
737 page = alloc_fresh_huge_page_node(h, next_nid);
742 next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
743 } while (next_nid != start_nid);
746 count_vm_event(HTLB_BUDDY_PGALLOC);
748 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
754 * helper for free_pool_huge_page() - return the previously saved
755 * node ["this node"] from which to free a huge page. Advance the
756 * next node id whether or not we find a free huge page to free so
757 * that the next attempt to free addresses the next node.
759 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
763 VM_BUG_ON(!nodes_allowed);
765 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
766 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
772 * Free huge page from pool from next node to free.
773 * Attempt to keep persistent huge pages more or less
774 * balanced over allowed nodes.
775 * Called with hugetlb_lock locked.
777 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
784 start_nid = hstate_next_node_to_free(h, nodes_allowed);
785 next_nid = start_nid;
789 * If we're returning unused surplus pages, only examine
790 * nodes with surplus pages.
792 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
793 !list_empty(&h->hugepage_freelists[next_nid])) {
795 list_entry(h->hugepage_freelists[next_nid].next,
797 list_del(&page->lru);
798 h->free_huge_pages--;
799 h->free_huge_pages_node[next_nid]--;
801 h->surplus_huge_pages--;
802 h->surplus_huge_pages_node[next_nid]--;
804 update_and_free_page(h, page);
808 next_nid = hstate_next_node_to_free(h, nodes_allowed);
809 } while (next_nid != start_nid);
814 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
819 if (h->order >= MAX_ORDER)
823 * Assume we will successfully allocate the surplus page to
824 * prevent racing processes from causing the surplus to exceed
827 * This however introduces a different race, where a process B
828 * tries to grow the static hugepage pool while alloc_pages() is
829 * called by process A. B will only examine the per-node
830 * counters in determining if surplus huge pages can be
831 * converted to normal huge pages in adjust_pool_surplus(). A
832 * won't be able to increment the per-node counter, until the
833 * lock is dropped by B, but B doesn't drop hugetlb_lock until
834 * no more huge pages can be converted from surplus to normal
835 * state (and doesn't try to convert again). Thus, we have a
836 * case where a surplus huge page exists, the pool is grown, and
837 * the surplus huge page still exists after, even though it
838 * should just have been converted to a normal huge page. This
839 * does not leak memory, though, as the hugepage will be freed
840 * once it is out of use. It also does not allow the counters to
841 * go out of whack in adjust_pool_surplus() as we don't modify
842 * the node values until we've gotten the hugepage and only the
843 * per-node value is checked there.
845 spin_lock(&hugetlb_lock);
846 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
847 spin_unlock(&hugetlb_lock);
851 h->surplus_huge_pages++;
853 spin_unlock(&hugetlb_lock);
855 if (nid == NUMA_NO_NODE)
856 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
857 __GFP_REPEAT|__GFP_NOWARN,
860 page = alloc_pages_exact_node(nid,
861 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
862 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
864 if (page && arch_prepare_hugepage(page)) {
865 __free_pages(page, huge_page_order(h));
869 spin_lock(&hugetlb_lock);
872 * This page is now managed by the hugetlb allocator and has
873 * no users -- drop the buddy allocator's reference.
875 put_page_testzero(page);
876 VM_BUG_ON(page_count(page));
877 r_nid = page_to_nid(page);
878 set_compound_page_dtor(page, free_huge_page);
880 * We incremented the global counters already
882 h->nr_huge_pages_node[r_nid]++;
883 h->surplus_huge_pages_node[r_nid]++;
884 __count_vm_event(HTLB_BUDDY_PGALLOC);
887 h->surplus_huge_pages--;
888 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
890 spin_unlock(&hugetlb_lock);
896 * This allocation function is useful in the context where vma is irrelevant.
897 * E.g. soft-offlining uses this function because it only cares physical
898 * address of error page.
900 struct page *alloc_huge_page_node(struct hstate *h, int nid)
904 spin_lock(&hugetlb_lock);
905 page = dequeue_huge_page_node(h, nid);
906 spin_unlock(&hugetlb_lock);
909 page = alloc_buddy_huge_page(h, nid);
915 * Increase the hugetlb pool such that it can accomodate a reservation
918 static int gather_surplus_pages(struct hstate *h, int delta)
920 struct list_head surplus_list;
921 struct page *page, *tmp;
923 int needed, allocated;
925 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
927 h->resv_huge_pages += delta;
932 INIT_LIST_HEAD(&surplus_list);
936 spin_unlock(&hugetlb_lock);
937 for (i = 0; i < needed; i++) {
938 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
941 * We were not able to allocate enough pages to
942 * satisfy the entire reservation so we free what
943 * we've allocated so far.
945 spin_lock(&hugetlb_lock);
950 list_add(&page->lru, &surplus_list);
955 * After retaking hugetlb_lock, we need to recalculate 'needed'
956 * because either resv_huge_pages or free_huge_pages may have changed.
958 spin_lock(&hugetlb_lock);
959 needed = (h->resv_huge_pages + delta) -
960 (h->free_huge_pages + allocated);
965 * The surplus_list now contains _at_least_ the number of extra pages
966 * needed to accomodate the reservation. Add the appropriate number
967 * of pages to the hugetlb pool and free the extras back to the buddy
968 * allocator. Commit the entire reservation here to prevent another
969 * process from stealing the pages as they are added to the pool but
970 * before they are reserved.
973 h->resv_huge_pages += delta;
976 /* Free the needed pages to the hugetlb pool */
977 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
980 list_del(&page->lru);
981 enqueue_huge_page(h, page);
984 /* Free unnecessary surplus pages to the buddy allocator */
985 if (!list_empty(&surplus_list)) {
986 spin_unlock(&hugetlb_lock);
987 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
988 list_del(&page->lru);
990 * The page has a reference count of zero already, so
991 * call free_huge_page directly instead of using
992 * put_page. This must be done with hugetlb_lock
993 * unlocked which is safe because free_huge_page takes
994 * hugetlb_lock before deciding how to free the page.
996 free_huge_page(page);
998 spin_lock(&hugetlb_lock);
1005 * When releasing a hugetlb pool reservation, any surplus pages that were
1006 * allocated to satisfy the reservation must be explicitly freed if they were
1008 * Called with hugetlb_lock held.
1010 static void return_unused_surplus_pages(struct hstate *h,
1011 unsigned long unused_resv_pages)
1013 unsigned long nr_pages;
1015 /* Uncommit the reservation */
1016 h->resv_huge_pages -= unused_resv_pages;
1018 /* Cannot return gigantic pages currently */
1019 if (h->order >= MAX_ORDER)
1022 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1025 * We want to release as many surplus pages as possible, spread
1026 * evenly across all nodes with memory. Iterate across these nodes
1027 * until we can no longer free unreserved surplus pages. This occurs
1028 * when the nodes with surplus pages have no free pages.
1029 * free_pool_huge_page() will balance the the freed pages across the
1030 * on-line nodes with memory and will handle the hstate accounting.
1032 while (nr_pages--) {
1033 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
1039 * Determine if the huge page at addr within the vma has an associated
1040 * reservation. Where it does not we will need to logically increase
1041 * reservation and actually increase quota before an allocation can occur.
1042 * Where any new reservation would be required the reservation change is
1043 * prepared, but not committed. Once the page has been quota'd allocated
1044 * an instantiated the change should be committed via vma_commit_reservation.
1045 * No action is required on failure.
1047 static long vma_needs_reservation(struct hstate *h,
1048 struct vm_area_struct *vma, unsigned long addr)
1050 struct address_space *mapping = vma->vm_file->f_mapping;
1051 struct inode *inode = mapping->host;
1053 if (vma->vm_flags & VM_MAYSHARE) {
1054 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1055 return region_chg(&inode->i_mapping->private_list,
1058 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1063 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1064 struct resv_map *reservations = vma_resv_map(vma);
1066 err = region_chg(&reservations->regions, idx, idx + 1);
1072 static void vma_commit_reservation(struct hstate *h,
1073 struct vm_area_struct *vma, unsigned long addr)
1075 struct address_space *mapping = vma->vm_file->f_mapping;
1076 struct inode *inode = mapping->host;
1078 if (vma->vm_flags & VM_MAYSHARE) {
1079 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1080 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1082 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1083 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1084 struct resv_map *reservations = vma_resv_map(vma);
1086 /* Mark this page used in the map. */
1087 region_add(&reservations->regions, idx, idx + 1);
1091 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1092 unsigned long addr, int avoid_reserve)
1094 struct hstate *h = hstate_vma(vma);
1096 struct address_space *mapping = vma->vm_file->f_mapping;
1097 struct inode *inode = mapping->host;
1101 * Processes that did not create the mapping will have no reserves and
1102 * will not have accounted against quota. Check that the quota can be
1103 * made before satisfying the allocation
1104 * MAP_NORESERVE mappings may also need pages and quota allocated
1105 * if no reserve mapping overlaps.
1107 chg = vma_needs_reservation(h, vma, addr);
1109 return ERR_PTR(chg);
1111 if (hugetlb_get_quota(inode->i_mapping, chg))
1112 return ERR_PTR(-ENOSPC);
1114 spin_lock(&hugetlb_lock);
1115 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1116 spin_unlock(&hugetlb_lock);
1119 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1121 hugetlb_put_quota(inode->i_mapping, chg);
1122 return ERR_PTR(-VM_FAULT_SIGBUS);
1126 set_page_refcounted(page);
1127 set_page_private(page, (unsigned long) mapping);
1129 vma_commit_reservation(h, vma, addr);
1134 int __weak alloc_bootmem_huge_page(struct hstate *h)
1136 struct huge_bootmem_page *m;
1137 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1142 addr = __alloc_bootmem_node_nopanic(
1143 NODE_DATA(hstate_next_node_to_alloc(h,
1144 &node_states[N_HIGH_MEMORY])),
1145 huge_page_size(h), huge_page_size(h), 0);
1149 * Use the beginning of the huge page to store the
1150 * huge_bootmem_page struct (until gather_bootmem
1151 * puts them into the mem_map).
1161 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1162 /* Put them into a private list first because mem_map is not up yet */
1163 list_add(&m->list, &huge_boot_pages);
1168 static void prep_compound_huge_page(struct page *page, int order)
1170 if (unlikely(order > (MAX_ORDER - 1)))
1171 prep_compound_gigantic_page(page, order);
1173 prep_compound_page(page, order);
1176 /* Put bootmem huge pages into the standard lists after mem_map is up */
1177 static void __init gather_bootmem_prealloc(void)
1179 struct huge_bootmem_page *m;
1181 list_for_each_entry(m, &huge_boot_pages, list) {
1182 struct page *page = virt_to_page(m);
1183 struct hstate *h = m->hstate;
1184 __ClearPageReserved(page);
1185 WARN_ON(page_count(page) != 1);
1186 prep_compound_huge_page(page, h->order);
1187 prep_new_huge_page(h, page, page_to_nid(page));
1191 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1195 for (i = 0; i < h->max_huge_pages; ++i) {
1196 if (h->order >= MAX_ORDER) {
1197 if (!alloc_bootmem_huge_page(h))
1199 } else if (!alloc_fresh_huge_page(h,
1200 &node_states[N_HIGH_MEMORY]))
1203 h->max_huge_pages = i;
1206 static void __init hugetlb_init_hstates(void)
1210 for_each_hstate(h) {
1211 /* oversize hugepages were init'ed in early boot */
1212 if (h->order < MAX_ORDER)
1213 hugetlb_hstate_alloc_pages(h);
1217 static char * __init memfmt(char *buf, unsigned long n)
1219 if (n >= (1UL << 30))
1220 sprintf(buf, "%lu GB", n >> 30);
1221 else if (n >= (1UL << 20))
1222 sprintf(buf, "%lu MB", n >> 20);
1224 sprintf(buf, "%lu KB", n >> 10);
1228 static void __init report_hugepages(void)
1232 for_each_hstate(h) {
1234 printk(KERN_INFO "HugeTLB registered %s page size, "
1235 "pre-allocated %ld pages\n",
1236 memfmt(buf, huge_page_size(h)),
1237 h->free_huge_pages);
1241 #ifdef CONFIG_HIGHMEM
1242 static void try_to_free_low(struct hstate *h, unsigned long count,
1243 nodemask_t *nodes_allowed)
1247 if (h->order >= MAX_ORDER)
1250 for_each_node_mask(i, *nodes_allowed) {
1251 struct page *page, *next;
1252 struct list_head *freel = &h->hugepage_freelists[i];
1253 list_for_each_entry_safe(page, next, freel, lru) {
1254 if (count >= h->nr_huge_pages)
1256 if (PageHighMem(page))
1258 list_del(&page->lru);
1259 update_and_free_page(h, page);
1260 h->free_huge_pages--;
1261 h->free_huge_pages_node[page_to_nid(page)]--;
1266 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1267 nodemask_t *nodes_allowed)
1273 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1274 * balanced by operating on them in a round-robin fashion.
1275 * Returns 1 if an adjustment was made.
1277 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1280 int start_nid, next_nid;
1283 VM_BUG_ON(delta != -1 && delta != 1);
1286 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1288 start_nid = hstate_next_node_to_free(h, nodes_allowed);
1289 next_nid = start_nid;
1295 * To shrink on this node, there must be a surplus page
1297 if (!h->surplus_huge_pages_node[nid]) {
1298 next_nid = hstate_next_node_to_alloc(h,
1305 * Surplus cannot exceed the total number of pages
1307 if (h->surplus_huge_pages_node[nid] >=
1308 h->nr_huge_pages_node[nid]) {
1309 next_nid = hstate_next_node_to_free(h,
1315 h->surplus_huge_pages += delta;
1316 h->surplus_huge_pages_node[nid] += delta;
1319 } while (next_nid != start_nid);
1324 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1325 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1326 nodemask_t *nodes_allowed)
1328 unsigned long min_count, ret;
1330 if (h->order >= MAX_ORDER)
1331 return h->max_huge_pages;
1334 * Increase the pool size
1335 * First take pages out of surplus state. Then make up the
1336 * remaining difference by allocating fresh huge pages.
1338 * We might race with alloc_buddy_huge_page() here and be unable
1339 * to convert a surplus huge page to a normal huge page. That is
1340 * not critical, though, it just means the overall size of the
1341 * pool might be one hugepage larger than it needs to be, but
1342 * within all the constraints specified by the sysctls.
1344 spin_lock(&hugetlb_lock);
1345 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1346 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1350 while (count > persistent_huge_pages(h)) {
1352 * If this allocation races such that we no longer need the
1353 * page, free_huge_page will handle it by freeing the page
1354 * and reducing the surplus.
1356 spin_unlock(&hugetlb_lock);
1357 ret = alloc_fresh_huge_page(h, nodes_allowed);
1358 spin_lock(&hugetlb_lock);
1362 /* Bail for signals. Probably ctrl-c from user */
1363 if (signal_pending(current))
1368 * Decrease the pool size
1369 * First return free pages to the buddy allocator (being careful
1370 * to keep enough around to satisfy reservations). Then place
1371 * pages into surplus state as needed so the pool will shrink
1372 * to the desired size as pages become free.
1374 * By placing pages into the surplus state independent of the
1375 * overcommit value, we are allowing the surplus pool size to
1376 * exceed overcommit. There are few sane options here. Since
1377 * alloc_buddy_huge_page() is checking the global counter,
1378 * though, we'll note that we're not allowed to exceed surplus
1379 * and won't grow the pool anywhere else. Not until one of the
1380 * sysctls are changed, or the surplus pages go out of use.
1382 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1383 min_count = max(count, min_count);
1384 try_to_free_low(h, min_count, nodes_allowed);
1385 while (min_count < persistent_huge_pages(h)) {
1386 if (!free_pool_huge_page(h, nodes_allowed, 0))
1389 while (count < persistent_huge_pages(h)) {
1390 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1394 ret = persistent_huge_pages(h);
1395 spin_unlock(&hugetlb_lock);
1399 #define HSTATE_ATTR_RO(_name) \
1400 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1402 #define HSTATE_ATTR(_name) \
1403 static struct kobj_attribute _name##_attr = \
1404 __ATTR(_name, 0644, _name##_show, _name##_store)
1406 static struct kobject *hugepages_kobj;
1407 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1409 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1411 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1415 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1416 if (hstate_kobjs[i] == kobj) {
1418 *nidp = NUMA_NO_NODE;
1422 return kobj_to_node_hstate(kobj, nidp);
1425 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1426 struct kobj_attribute *attr, char *buf)
1429 unsigned long nr_huge_pages;
1432 h = kobj_to_hstate(kobj, &nid);
1433 if (nid == NUMA_NO_NODE)
1434 nr_huge_pages = h->nr_huge_pages;
1436 nr_huge_pages = h->nr_huge_pages_node[nid];
1438 return sprintf(buf, "%lu\n", nr_huge_pages);
1440 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1441 struct kobject *kobj, struct kobj_attribute *attr,
1442 const char *buf, size_t len)
1446 unsigned long count;
1448 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1450 err = strict_strtoul(buf, 10, &count);
1454 h = kobj_to_hstate(kobj, &nid);
1455 if (nid == NUMA_NO_NODE) {
1457 * global hstate attribute
1459 if (!(obey_mempolicy &&
1460 init_nodemask_of_mempolicy(nodes_allowed))) {
1461 NODEMASK_FREE(nodes_allowed);
1462 nodes_allowed = &node_states[N_HIGH_MEMORY];
1464 } else if (nodes_allowed) {
1466 * per node hstate attribute: adjust count to global,
1467 * but restrict alloc/free to the specified node.
1469 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1470 init_nodemask_of_node(nodes_allowed, nid);
1472 nodes_allowed = &node_states[N_HIGH_MEMORY];
1474 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1476 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1477 NODEMASK_FREE(nodes_allowed);
1482 static ssize_t nr_hugepages_show(struct kobject *kobj,
1483 struct kobj_attribute *attr, char *buf)
1485 return nr_hugepages_show_common(kobj, attr, buf);
1488 static ssize_t nr_hugepages_store(struct kobject *kobj,
1489 struct kobj_attribute *attr, const char *buf, size_t len)
1491 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1493 HSTATE_ATTR(nr_hugepages);
1498 * hstate attribute for optionally mempolicy-based constraint on persistent
1499 * huge page alloc/free.
1501 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1502 struct kobj_attribute *attr, char *buf)
1504 return nr_hugepages_show_common(kobj, attr, buf);
1507 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1508 struct kobj_attribute *attr, const char *buf, size_t len)
1510 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1512 HSTATE_ATTR(nr_hugepages_mempolicy);
1516 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1517 struct kobj_attribute *attr, char *buf)
1519 struct hstate *h = kobj_to_hstate(kobj, NULL);
1520 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1522 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1523 struct kobj_attribute *attr, const char *buf, size_t count)
1526 unsigned long input;
1527 struct hstate *h = kobj_to_hstate(kobj, NULL);
1529 err = strict_strtoul(buf, 10, &input);
1533 spin_lock(&hugetlb_lock);
1534 h->nr_overcommit_huge_pages = input;
1535 spin_unlock(&hugetlb_lock);
1539 HSTATE_ATTR(nr_overcommit_hugepages);
1541 static ssize_t free_hugepages_show(struct kobject *kobj,
1542 struct kobj_attribute *attr, char *buf)
1545 unsigned long free_huge_pages;
1548 h = kobj_to_hstate(kobj, &nid);
1549 if (nid == NUMA_NO_NODE)
1550 free_huge_pages = h->free_huge_pages;
1552 free_huge_pages = h->free_huge_pages_node[nid];
1554 return sprintf(buf, "%lu\n", free_huge_pages);
1556 HSTATE_ATTR_RO(free_hugepages);
1558 static ssize_t resv_hugepages_show(struct kobject *kobj,
1559 struct kobj_attribute *attr, char *buf)
1561 struct hstate *h = kobj_to_hstate(kobj, NULL);
1562 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1564 HSTATE_ATTR_RO(resv_hugepages);
1566 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1567 struct kobj_attribute *attr, char *buf)
1570 unsigned long surplus_huge_pages;
1573 h = kobj_to_hstate(kobj, &nid);
1574 if (nid == NUMA_NO_NODE)
1575 surplus_huge_pages = h->surplus_huge_pages;
1577 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1579 return sprintf(buf, "%lu\n", surplus_huge_pages);
1581 HSTATE_ATTR_RO(surplus_hugepages);
1583 static struct attribute *hstate_attrs[] = {
1584 &nr_hugepages_attr.attr,
1585 &nr_overcommit_hugepages_attr.attr,
1586 &free_hugepages_attr.attr,
1587 &resv_hugepages_attr.attr,
1588 &surplus_hugepages_attr.attr,
1590 &nr_hugepages_mempolicy_attr.attr,
1595 static struct attribute_group hstate_attr_group = {
1596 .attrs = hstate_attrs,
1599 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1600 struct kobject **hstate_kobjs,
1601 struct attribute_group *hstate_attr_group)
1604 int hi = h - hstates;
1606 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1607 if (!hstate_kobjs[hi])
1610 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1612 kobject_put(hstate_kobjs[hi]);
1617 static void __init hugetlb_sysfs_init(void)
1622 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1623 if (!hugepages_kobj)
1626 for_each_hstate(h) {
1627 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1628 hstate_kobjs, &hstate_attr_group);
1630 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1638 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1639 * with node sysdevs in node_devices[] using a parallel array. The array
1640 * index of a node sysdev or _hstate == node id.
1641 * This is here to avoid any static dependency of the node sysdev driver, in
1642 * the base kernel, on the hugetlb module.
1644 struct node_hstate {
1645 struct kobject *hugepages_kobj;
1646 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1648 struct node_hstate node_hstates[MAX_NUMNODES];
1651 * A subset of global hstate attributes for node sysdevs
1653 static struct attribute *per_node_hstate_attrs[] = {
1654 &nr_hugepages_attr.attr,
1655 &free_hugepages_attr.attr,
1656 &surplus_hugepages_attr.attr,
1660 static struct attribute_group per_node_hstate_attr_group = {
1661 .attrs = per_node_hstate_attrs,
1665 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1666 * Returns node id via non-NULL nidp.
1668 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1672 for (nid = 0; nid < nr_node_ids; nid++) {
1673 struct node_hstate *nhs = &node_hstates[nid];
1675 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1676 if (nhs->hstate_kobjs[i] == kobj) {
1688 * Unregister hstate attributes from a single node sysdev.
1689 * No-op if no hstate attributes attached.
1691 void hugetlb_unregister_node(struct node *node)
1694 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1696 if (!nhs->hugepages_kobj)
1697 return; /* no hstate attributes */
1700 if (nhs->hstate_kobjs[h - hstates]) {
1701 kobject_put(nhs->hstate_kobjs[h - hstates]);
1702 nhs->hstate_kobjs[h - hstates] = NULL;
1705 kobject_put(nhs->hugepages_kobj);
1706 nhs->hugepages_kobj = NULL;
1710 * hugetlb module exit: unregister hstate attributes from node sysdevs
1713 static void hugetlb_unregister_all_nodes(void)
1718 * disable node sysdev registrations.
1720 register_hugetlbfs_with_node(NULL, NULL);
1723 * remove hstate attributes from any nodes that have them.
1725 for (nid = 0; nid < nr_node_ids; nid++)
1726 hugetlb_unregister_node(&node_devices[nid]);
1730 * Register hstate attributes for a single node sysdev.
1731 * No-op if attributes already registered.
1733 void hugetlb_register_node(struct node *node)
1736 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1739 if (nhs->hugepages_kobj)
1740 return; /* already allocated */
1742 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1743 &node->sysdev.kobj);
1744 if (!nhs->hugepages_kobj)
1747 for_each_hstate(h) {
1748 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1750 &per_node_hstate_attr_group);
1752 printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
1754 h->name, node->sysdev.id);
1755 hugetlb_unregister_node(node);
1762 * hugetlb init time: register hstate attributes for all registered node
1763 * sysdevs of nodes that have memory. All on-line nodes should have
1764 * registered their associated sysdev by this time.
1766 static void hugetlb_register_all_nodes(void)
1770 for_each_node_state(nid, N_HIGH_MEMORY) {
1771 struct node *node = &node_devices[nid];
1772 if (node->sysdev.id == nid)
1773 hugetlb_register_node(node);
1777 * Let the node sysdev driver know we're here so it can
1778 * [un]register hstate attributes on node hotplug.
1780 register_hugetlbfs_with_node(hugetlb_register_node,
1781 hugetlb_unregister_node);
1783 #else /* !CONFIG_NUMA */
1785 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1793 static void hugetlb_unregister_all_nodes(void) { }
1795 static void hugetlb_register_all_nodes(void) { }
1799 static void __exit hugetlb_exit(void)
1803 hugetlb_unregister_all_nodes();
1805 for_each_hstate(h) {
1806 kobject_put(hstate_kobjs[h - hstates]);
1809 kobject_put(hugepages_kobj);
1811 module_exit(hugetlb_exit);
1813 static int __init hugetlb_init(void)
1815 /* Some platform decide whether they support huge pages at boot
1816 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1817 * there is no such support
1819 if (HPAGE_SHIFT == 0)
1822 if (!size_to_hstate(default_hstate_size)) {
1823 default_hstate_size = HPAGE_SIZE;
1824 if (!size_to_hstate(default_hstate_size))
1825 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1827 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1828 if (default_hstate_max_huge_pages)
1829 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1831 hugetlb_init_hstates();
1833 gather_bootmem_prealloc();
1837 hugetlb_sysfs_init();
1839 hugetlb_register_all_nodes();
1843 module_init(hugetlb_init);
1845 /* Should be called on processing a hugepagesz=... option */
1846 void __init hugetlb_add_hstate(unsigned order)
1851 if (size_to_hstate(PAGE_SIZE << order)) {
1852 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1855 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1857 h = &hstates[max_hstate++];
1859 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1860 h->nr_huge_pages = 0;
1861 h->free_huge_pages = 0;
1862 for (i = 0; i < MAX_NUMNODES; ++i)
1863 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1864 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
1865 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1866 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1867 huge_page_size(h)/1024);
1872 static int __init hugetlb_nrpages_setup(char *s)
1875 static unsigned long *last_mhp;
1878 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1879 * so this hugepages= parameter goes to the "default hstate".
1882 mhp = &default_hstate_max_huge_pages;
1884 mhp = &parsed_hstate->max_huge_pages;
1886 if (mhp == last_mhp) {
1887 printk(KERN_WARNING "hugepages= specified twice without "
1888 "interleaving hugepagesz=, ignoring\n");
1892 if (sscanf(s, "%lu", mhp) <= 0)
1896 * Global state is always initialized later in hugetlb_init.
1897 * But we need to allocate >= MAX_ORDER hstates here early to still
1898 * use the bootmem allocator.
1900 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1901 hugetlb_hstate_alloc_pages(parsed_hstate);
1907 __setup("hugepages=", hugetlb_nrpages_setup);
1909 static int __init hugetlb_default_setup(char *s)
1911 default_hstate_size = memparse(s, &s);
1914 __setup("default_hugepagesz=", hugetlb_default_setup);
1916 static unsigned int cpuset_mems_nr(unsigned int *array)
1919 unsigned int nr = 0;
1921 for_each_node_mask(node, cpuset_current_mems_allowed)
1927 #ifdef CONFIG_SYSCTL
1928 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
1929 struct ctl_table *table, int write,
1930 void __user *buffer, size_t *length, loff_t *ppos)
1932 struct hstate *h = &default_hstate;
1936 tmp = h->max_huge_pages;
1939 table->maxlen = sizeof(unsigned long);
1940 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1943 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
1944 GFP_KERNEL | __GFP_NORETRY);
1945 if (!(obey_mempolicy &&
1946 init_nodemask_of_mempolicy(nodes_allowed))) {
1947 NODEMASK_FREE(nodes_allowed);
1948 nodes_allowed = &node_states[N_HIGH_MEMORY];
1950 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
1952 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1953 NODEMASK_FREE(nodes_allowed);
1959 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1960 void __user *buffer, size_t *length, loff_t *ppos)
1963 return hugetlb_sysctl_handler_common(false, table, write,
1964 buffer, length, ppos);
1968 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
1969 void __user *buffer, size_t *length, loff_t *ppos)
1971 return hugetlb_sysctl_handler_common(true, table, write,
1972 buffer, length, ppos);
1974 #endif /* CONFIG_NUMA */
1976 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1977 void __user *buffer,
1978 size_t *length, loff_t *ppos)
1980 proc_dointvec(table, write, buffer, length, ppos);
1981 if (hugepages_treat_as_movable)
1982 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1984 htlb_alloc_mask = GFP_HIGHUSER;
1988 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1989 void __user *buffer,
1990 size_t *length, loff_t *ppos)
1992 struct hstate *h = &default_hstate;
1996 tmp = h->nr_overcommit_huge_pages;
1999 table->maxlen = sizeof(unsigned long);
2000 proc_doulongvec_minmax(table, write, buffer, length, ppos);
2003 spin_lock(&hugetlb_lock);
2004 h->nr_overcommit_huge_pages = tmp;
2005 spin_unlock(&hugetlb_lock);
2011 #endif /* CONFIG_SYSCTL */
2013 void hugetlb_report_meminfo(struct seq_file *m)
2015 struct hstate *h = &default_hstate;
2017 "HugePages_Total: %5lu\n"
2018 "HugePages_Free: %5lu\n"
2019 "HugePages_Rsvd: %5lu\n"
2020 "HugePages_Surp: %5lu\n"
2021 "Hugepagesize: %8lu kB\n",
2025 h->surplus_huge_pages,
2026 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2029 int hugetlb_report_node_meminfo(int nid, char *buf)
2031 struct hstate *h = &default_hstate;
2033 "Node %d HugePages_Total: %5u\n"
2034 "Node %d HugePages_Free: %5u\n"
2035 "Node %d HugePages_Surp: %5u\n",
2036 nid, h->nr_huge_pages_node[nid],
2037 nid, h->free_huge_pages_node[nid],
2038 nid, h->surplus_huge_pages_node[nid]);
2041 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2042 unsigned long hugetlb_total_pages(void)
2044 struct hstate *h = &default_hstate;
2045 return h->nr_huge_pages * pages_per_huge_page(h);
2048 static int hugetlb_acct_memory(struct hstate *h, long delta)
2052 spin_lock(&hugetlb_lock);
2054 * When cpuset is configured, it breaks the strict hugetlb page
2055 * reservation as the accounting is done on a global variable. Such
2056 * reservation is completely rubbish in the presence of cpuset because
2057 * the reservation is not checked against page availability for the
2058 * current cpuset. Application can still potentially OOM'ed by kernel
2059 * with lack of free htlb page in cpuset that the task is in.
2060 * Attempt to enforce strict accounting with cpuset is almost
2061 * impossible (or too ugly) because cpuset is too fluid that
2062 * task or memory node can be dynamically moved between cpusets.
2064 * The change of semantics for shared hugetlb mapping with cpuset is
2065 * undesirable. However, in order to preserve some of the semantics,
2066 * we fall back to check against current free page availability as
2067 * a best attempt and hopefully to minimize the impact of changing
2068 * semantics that cpuset has.
2071 if (gather_surplus_pages(h, delta) < 0)
2074 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2075 return_unused_surplus_pages(h, delta);
2082 return_unused_surplus_pages(h, (unsigned long) -delta);
2085 spin_unlock(&hugetlb_lock);
2089 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2091 struct resv_map *reservations = vma_resv_map(vma);
2094 * This new VMA should share its siblings reservation map if present.
2095 * The VMA will only ever have a valid reservation map pointer where
2096 * it is being copied for another still existing VMA. As that VMA
2097 * has a reference to the reservation map it cannot dissappear until
2098 * after this open call completes. It is therefore safe to take a
2099 * new reference here without additional locking.
2102 kref_get(&reservations->refs);
2105 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2107 struct hstate *h = hstate_vma(vma);
2108 struct resv_map *reservations = vma_resv_map(vma);
2109 unsigned long reserve;
2110 unsigned long start;
2114 start = vma_hugecache_offset(h, vma, vma->vm_start);
2115 end = vma_hugecache_offset(h, vma, vma->vm_end);
2117 reserve = (end - start) -
2118 region_count(&reservations->regions, start, end);
2120 kref_put(&reservations->refs, resv_map_release);
2123 hugetlb_acct_memory(h, -reserve);
2124 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
2130 * We cannot handle pagefaults against hugetlb pages at all. They cause
2131 * handle_mm_fault() to try to instantiate regular-sized pages in the
2132 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2135 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2141 const struct vm_operations_struct hugetlb_vm_ops = {
2142 .fault = hugetlb_vm_op_fault,
2143 .open = hugetlb_vm_op_open,
2144 .close = hugetlb_vm_op_close,
2147 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2154 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
2156 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
2158 entry = pte_mkyoung(entry);
2159 entry = pte_mkhuge(entry);
2164 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2165 unsigned long address, pte_t *ptep)
2169 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2170 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
2171 update_mmu_cache(vma, address, ptep);
2176 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2177 struct vm_area_struct *vma)
2179 pte_t *src_pte, *dst_pte, entry;
2180 struct page *ptepage;
2183 struct hstate *h = hstate_vma(vma);
2184 unsigned long sz = huge_page_size(h);
2186 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2188 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2189 src_pte = huge_pte_offset(src, addr);
2192 dst_pte = huge_pte_alloc(dst, addr, sz);
2196 /* If the pagetables are shared don't copy or take references */
2197 if (dst_pte == src_pte)
2200 spin_lock(&dst->page_table_lock);
2201 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2202 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2204 huge_ptep_set_wrprotect(src, addr, src_pte);
2205 entry = huge_ptep_get(src_pte);
2206 ptepage = pte_page(entry);
2208 page_dup_rmap(ptepage);
2209 set_huge_pte_at(dst, addr, dst_pte, entry);
2211 spin_unlock(&src->page_table_lock);
2212 spin_unlock(&dst->page_table_lock);
2220 static int is_hugetlb_entry_migration(pte_t pte)
2224 if (huge_pte_none(pte) || pte_present(pte))
2226 swp = pte_to_swp_entry(pte);
2227 if (non_swap_entry(swp) && is_migration_entry(swp)) {
2233 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2237 if (huge_pte_none(pte) || pte_present(pte))
2239 swp = pte_to_swp_entry(pte);
2240 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) {
2246 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2247 unsigned long end, struct page *ref_page)
2249 struct mm_struct *mm = vma->vm_mm;
2250 unsigned long address;
2255 struct hstate *h = hstate_vma(vma);
2256 unsigned long sz = huge_page_size(h);
2259 * A page gathering list, protected by per file i_mmap_lock. The
2260 * lock is used to avoid list corruption from multiple unmapping
2261 * of the same page since we are using page->lru.
2263 LIST_HEAD(page_list);
2265 WARN_ON(!is_vm_hugetlb_page(vma));
2266 BUG_ON(start & ~huge_page_mask(h));
2267 BUG_ON(end & ~huge_page_mask(h));
2269 mmu_notifier_invalidate_range_start(mm, start, end);
2270 spin_lock(&mm->page_table_lock);
2271 for (address = start; address < end; address += sz) {
2272 ptep = huge_pte_offset(mm, address);
2276 if (huge_pmd_unshare(mm, &address, ptep))
2280 * If a reference page is supplied, it is because a specific
2281 * page is being unmapped, not a range. Ensure the page we
2282 * are about to unmap is the actual page of interest.
2285 pte = huge_ptep_get(ptep);
2286 if (huge_pte_none(pte))
2288 page = pte_page(pte);
2289 if (page != ref_page)
2293 * Mark the VMA as having unmapped its page so that
2294 * future faults in this VMA will fail rather than
2295 * looking like data was lost
2297 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2300 pte = huge_ptep_get_and_clear(mm, address, ptep);
2301 if (huge_pte_none(pte))
2305 * HWPoisoned hugepage is already unmapped and dropped reference
2307 if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
2310 page = pte_page(pte);
2312 set_page_dirty(page);
2313 list_add(&page->lru, &page_list);
2315 spin_unlock(&mm->page_table_lock);
2316 flush_tlb_range(vma, start, end);
2317 mmu_notifier_invalidate_range_end(mm, start, end);
2318 list_for_each_entry_safe(page, tmp, &page_list, lru) {
2319 page_remove_rmap(page);
2320 list_del(&page->lru);
2325 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2326 unsigned long end, struct page *ref_page)
2328 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2329 __unmap_hugepage_range(vma, start, end, ref_page);
2330 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2334 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2335 * mappping it owns the reserve page for. The intention is to unmap the page
2336 * from other VMAs and let the children be SIGKILLed if they are faulting the
2339 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2340 struct page *page, unsigned long address)
2342 struct hstate *h = hstate_vma(vma);
2343 struct vm_area_struct *iter_vma;
2344 struct address_space *mapping;
2345 struct prio_tree_iter iter;
2349 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2350 * from page cache lookup which is in HPAGE_SIZE units.
2352 address = address & huge_page_mask(h);
2353 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
2354 + (vma->vm_pgoff >> PAGE_SHIFT);
2355 mapping = (struct address_space *)page_private(page);
2358 * Take the mapping lock for the duration of the table walk. As
2359 * this mapping should be shared between all the VMAs,
2360 * __unmap_hugepage_range() is called as the lock is already held
2362 spin_lock(&mapping->i_mmap_lock);
2363 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
2364 /* Do not unmap the current VMA */
2365 if (iter_vma == vma)
2369 * Unmap the page from other VMAs without their own reserves.
2370 * They get marked to be SIGKILLed if they fault in these
2371 * areas. This is because a future no-page fault on this VMA
2372 * could insert a zeroed page instead of the data existing
2373 * from the time of fork. This would look like data corruption
2375 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2376 __unmap_hugepage_range(iter_vma,
2377 address, address + huge_page_size(h),
2380 spin_unlock(&mapping->i_mmap_lock);
2386 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2388 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2389 unsigned long address, pte_t *ptep, pte_t pte,
2390 struct page *pagecache_page)
2392 struct hstate *h = hstate_vma(vma);
2393 struct page *old_page, *new_page;
2395 int outside_reserve = 0;
2397 old_page = pte_page(pte);
2400 /* If no-one else is actually using this page, avoid the copy
2401 * and just make the page writable */
2402 avoidcopy = (page_mapcount(old_page) == 1);
2404 if (PageAnon(old_page))
2405 page_move_anon_rmap(old_page, vma, address);
2406 set_huge_ptep_writable(vma, address, ptep);
2411 * If the process that created a MAP_PRIVATE mapping is about to
2412 * perform a COW due to a shared page count, attempt to satisfy
2413 * the allocation without using the existing reserves. The pagecache
2414 * page is used to determine if the reserve at this address was
2415 * consumed or not. If reserves were used, a partial faulted mapping
2416 * at the time of fork() could consume its reserves on COW instead
2417 * of the full address range.
2419 if (!(vma->vm_flags & VM_MAYSHARE) &&
2420 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2421 old_page != pagecache_page)
2422 outside_reserve = 1;
2424 page_cache_get(old_page);
2426 /* Drop page_table_lock as buddy allocator may be called */
2427 spin_unlock(&mm->page_table_lock);
2428 new_page = alloc_huge_page(vma, address, outside_reserve);
2430 if (IS_ERR(new_page)) {
2431 page_cache_release(old_page);
2434 * If a process owning a MAP_PRIVATE mapping fails to COW,
2435 * it is due to references held by a child and an insufficient
2436 * huge page pool. To guarantee the original mappers
2437 * reliability, unmap the page from child processes. The child
2438 * may get SIGKILLed if it later faults.
2440 if (outside_reserve) {
2441 BUG_ON(huge_pte_none(pte));
2442 if (unmap_ref_private(mm, vma, old_page, address)) {
2443 BUG_ON(page_count(old_page) != 1);
2444 BUG_ON(huge_pte_none(pte));
2445 spin_lock(&mm->page_table_lock);
2446 goto retry_avoidcopy;
2451 /* Caller expects lock to be held */
2452 spin_lock(&mm->page_table_lock);
2453 return -PTR_ERR(new_page);
2457 * When the original hugepage is shared one, it does not have
2458 * anon_vma prepared.
2460 if (unlikely(anon_vma_prepare(vma)))
2461 return VM_FAULT_OOM;
2463 copy_user_huge_page(new_page, old_page, address, vma);
2464 __SetPageUptodate(new_page);
2467 * Retake the page_table_lock to check for racing updates
2468 * before the page tables are altered
2470 spin_lock(&mm->page_table_lock);
2471 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2472 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2474 mmu_notifier_invalidate_range_start(mm,
2475 address & huge_page_mask(h),
2476 (address & huge_page_mask(h)) + huge_page_size(h));
2477 huge_ptep_clear_flush(vma, address, ptep);
2478 set_huge_pte_at(mm, address, ptep,
2479 make_huge_pte(vma, new_page, 1));
2480 page_remove_rmap(old_page);
2481 hugepage_add_new_anon_rmap(new_page, vma, address);
2482 /* Make the old page be freed below */
2483 new_page = old_page;
2484 mmu_notifier_invalidate_range_end(mm,
2485 address & huge_page_mask(h),
2486 (address & huge_page_mask(h)) + huge_page_size(h));
2488 page_cache_release(new_page);
2489 page_cache_release(old_page);
2493 /* Return the pagecache page at a given address within a VMA */
2494 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2495 struct vm_area_struct *vma, unsigned long address)
2497 struct address_space *mapping;
2500 mapping = vma->vm_file->f_mapping;
2501 idx = vma_hugecache_offset(h, vma, address);
2503 return find_lock_page(mapping, idx);
2507 * Return whether there is a pagecache page to back given address within VMA.
2508 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2510 static bool hugetlbfs_pagecache_present(struct hstate *h,
2511 struct vm_area_struct *vma, unsigned long address)
2513 struct address_space *mapping;
2517 mapping = vma->vm_file->f_mapping;
2518 idx = vma_hugecache_offset(h, vma, address);
2520 page = find_get_page(mapping, idx);
2523 return page != NULL;
2526 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2527 unsigned long address, pte_t *ptep, unsigned int flags)
2529 struct hstate *h = hstate_vma(vma);
2530 int ret = VM_FAULT_SIGBUS;
2534 struct address_space *mapping;
2538 * Currently, we are forced to kill the process in the event the
2539 * original mapper has unmapped pages from the child due to a failed
2540 * COW. Warn that such a situation has occured as it may not be obvious
2542 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2544 "PID %d killed due to inadequate hugepage pool\n",
2549 mapping = vma->vm_file->f_mapping;
2550 idx = vma_hugecache_offset(h, vma, address);
2553 * Use page lock to guard against racing truncation
2554 * before we get page_table_lock.
2557 page = find_lock_page(mapping, idx);
2559 size = i_size_read(mapping->host) >> huge_page_shift(h);
2562 page = alloc_huge_page(vma, address, 0);
2564 ret = -PTR_ERR(page);
2567 clear_huge_page(page, address, huge_page_size(h));
2568 __SetPageUptodate(page);
2570 if (vma->vm_flags & VM_MAYSHARE) {
2572 struct inode *inode = mapping->host;
2574 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2582 spin_lock(&inode->i_lock);
2583 inode->i_blocks += blocks_per_huge_page(h);
2584 spin_unlock(&inode->i_lock);
2585 page_dup_rmap(page);
2588 if (unlikely(anon_vma_prepare(vma))) {
2590 goto backout_unlocked;
2592 hugepage_add_new_anon_rmap(page, vma, address);
2596 * If memory error occurs between mmap() and fault, some process
2597 * don't have hwpoisoned swap entry for errored virtual address.
2598 * So we need to block hugepage fault by PG_hwpoison bit check.
2600 if (unlikely(PageHWPoison(page))) {
2601 ret = VM_FAULT_HWPOISON;
2602 goto backout_unlocked;
2604 page_dup_rmap(page);
2608 * If we are going to COW a private mapping later, we examine the
2609 * pending reservations for this page now. This will ensure that
2610 * any allocations necessary to record that reservation occur outside
2613 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2614 if (vma_needs_reservation(h, vma, address) < 0) {
2616 goto backout_unlocked;
2619 spin_lock(&mm->page_table_lock);
2620 size = i_size_read(mapping->host) >> huge_page_shift(h);
2625 if (!huge_pte_none(huge_ptep_get(ptep)))
2628 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2629 && (vma->vm_flags & VM_SHARED)));
2630 set_huge_pte_at(mm, address, ptep, new_pte);
2632 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2633 /* Optimization, do the COW without a second fault */
2634 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2637 spin_unlock(&mm->page_table_lock);
2643 spin_unlock(&mm->page_table_lock);
2650 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2651 unsigned long address, unsigned int flags)
2656 struct page *page = NULL;
2657 struct page *pagecache_page = NULL;
2658 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2659 struct hstate *h = hstate_vma(vma);
2661 ptep = huge_pte_offset(mm, address);
2663 entry = huge_ptep_get(ptep);
2664 if (unlikely(is_hugetlb_entry_migration(entry))) {
2665 migration_entry_wait(mm, (pmd_t *)ptep, address);
2667 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2668 return VM_FAULT_HWPOISON;
2671 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2673 return VM_FAULT_OOM;
2676 * Serialize hugepage allocation and instantiation, so that we don't
2677 * get spurious allocation failures if two CPUs race to instantiate
2678 * the same page in the page cache.
2680 mutex_lock(&hugetlb_instantiation_mutex);
2681 entry = huge_ptep_get(ptep);
2682 if (huge_pte_none(entry)) {
2683 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2690 * If we are going to COW the mapping later, we examine the pending
2691 * reservations for this page now. This will ensure that any
2692 * allocations necessary to record that reservation occur outside the
2693 * spinlock. For private mappings, we also lookup the pagecache
2694 * page now as it is used to determine if a reservation has been
2697 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2698 if (vma_needs_reservation(h, vma, address) < 0) {
2703 if (!(vma->vm_flags & VM_MAYSHARE))
2704 pagecache_page = hugetlbfs_pagecache_page(h,
2709 * hugetlb_cow() requires page locks of pte_page(entry) and
2710 * pagecache_page, so here we need take the former one
2711 * when page != pagecache_page or !pagecache_page.
2712 * Note that locking order is always pagecache_page -> page,
2713 * so no worry about deadlock.
2715 page = pte_page(entry);
2716 if (page != pagecache_page)
2719 spin_lock(&mm->page_table_lock);
2720 /* Check for a racing update before calling hugetlb_cow */
2721 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2722 goto out_page_table_lock;
2725 if (flags & FAULT_FLAG_WRITE) {
2726 if (!pte_write(entry)) {
2727 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2729 goto out_page_table_lock;
2731 entry = pte_mkdirty(entry);
2733 entry = pte_mkyoung(entry);
2734 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2735 flags & FAULT_FLAG_WRITE))
2736 update_mmu_cache(vma, address, ptep);
2738 out_page_table_lock:
2739 spin_unlock(&mm->page_table_lock);
2741 if (pagecache_page) {
2742 unlock_page(pagecache_page);
2743 put_page(pagecache_page);
2748 mutex_unlock(&hugetlb_instantiation_mutex);
2753 /* Can be overriden by architectures */
2754 __attribute__((weak)) struct page *
2755 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2756 pud_t *pud, int write)
2762 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2763 struct page **pages, struct vm_area_struct **vmas,
2764 unsigned long *position, int *length, int i,
2767 unsigned long pfn_offset;
2768 unsigned long vaddr = *position;
2769 int remainder = *length;
2770 struct hstate *h = hstate_vma(vma);
2772 spin_lock(&mm->page_table_lock);
2773 while (vaddr < vma->vm_end && remainder) {
2779 * Some archs (sparc64, sh*) have multiple pte_ts to
2780 * each hugepage. We have to make sure we get the
2781 * first, for the page indexing below to work.
2783 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2784 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2787 * When coredumping, it suits get_dump_page if we just return
2788 * an error where there's an empty slot with no huge pagecache
2789 * to back it. This way, we avoid allocating a hugepage, and
2790 * the sparse dumpfile avoids allocating disk blocks, but its
2791 * huge holes still show up with zeroes where they need to be.
2793 if (absent && (flags & FOLL_DUMP) &&
2794 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2800 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2803 spin_unlock(&mm->page_table_lock);
2804 ret = hugetlb_fault(mm, vma, vaddr,
2805 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2806 spin_lock(&mm->page_table_lock);
2807 if (!(ret & VM_FAULT_ERROR))
2814 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2815 page = pte_page(huge_ptep_get(pte));
2818 pages[i] = mem_map_offset(page, pfn_offset);
2829 if (vaddr < vma->vm_end && remainder &&
2830 pfn_offset < pages_per_huge_page(h)) {
2832 * We use pfn_offset to avoid touching the pageframes
2833 * of this compound page.
2838 spin_unlock(&mm->page_table_lock);
2839 *length = remainder;
2842 return i ? i : -EFAULT;
2845 void hugetlb_change_protection(struct vm_area_struct *vma,
2846 unsigned long address, unsigned long end, pgprot_t newprot)
2848 struct mm_struct *mm = vma->vm_mm;
2849 unsigned long start = address;
2852 struct hstate *h = hstate_vma(vma);
2854 BUG_ON(address >= end);
2855 flush_cache_range(vma, address, end);
2857 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2858 spin_lock(&mm->page_table_lock);
2859 for (; address < end; address += huge_page_size(h)) {
2860 ptep = huge_pte_offset(mm, address);
2863 if (huge_pmd_unshare(mm, &address, ptep))
2865 if (!huge_pte_none(huge_ptep_get(ptep))) {
2866 pte = huge_ptep_get_and_clear(mm, address, ptep);
2867 pte = pte_mkhuge(pte_modify(pte, newprot));
2868 set_huge_pte_at(mm, address, ptep, pte);
2871 spin_unlock(&mm->page_table_lock);
2872 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2874 flush_tlb_range(vma, start, end);
2877 int hugetlb_reserve_pages(struct inode *inode,
2879 struct vm_area_struct *vma,
2883 struct hstate *h = hstate_inode(inode);
2886 * Only apply hugepage reservation if asked. At fault time, an
2887 * attempt will be made for VM_NORESERVE to allocate a page
2888 * and filesystem quota without using reserves
2890 if (acctflag & VM_NORESERVE)
2894 * Shared mappings base their reservation on the number of pages that
2895 * are already allocated on behalf of the file. Private mappings need
2896 * to reserve the full area even if read-only as mprotect() may be
2897 * called to make the mapping read-write. Assume !vma is a shm mapping
2899 if (!vma || vma->vm_flags & VM_MAYSHARE)
2900 chg = region_chg(&inode->i_mapping->private_list, from, to);
2902 struct resv_map *resv_map = resv_map_alloc();
2908 set_vma_resv_map(vma, resv_map);
2909 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2915 /* There must be enough filesystem quota for the mapping */
2916 if (hugetlb_get_quota(inode->i_mapping, chg))
2920 * Check enough hugepages are available for the reservation.
2921 * Hand back the quota if there are not
2923 ret = hugetlb_acct_memory(h, chg);
2925 hugetlb_put_quota(inode->i_mapping, chg);
2930 * Account for the reservations made. Shared mappings record regions
2931 * that have reservations as they are shared by multiple VMAs.
2932 * When the last VMA disappears, the region map says how much
2933 * the reservation was and the page cache tells how much of
2934 * the reservation was consumed. Private mappings are per-VMA and
2935 * only the consumed reservations are tracked. When the VMA
2936 * disappears, the original reservation is the VMA size and the
2937 * consumed reservations are stored in the map. Hence, nothing
2938 * else has to be done for private mappings here
2940 if (!vma || vma->vm_flags & VM_MAYSHARE)
2941 region_add(&inode->i_mapping->private_list, from, to);
2945 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2947 struct hstate *h = hstate_inode(inode);
2948 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2950 spin_lock(&inode->i_lock);
2951 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2952 spin_unlock(&inode->i_lock);
2954 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2955 hugetlb_acct_memory(h, -(chg - freed));
2958 /* Should be called in hugetlb_lock */
2959 static int is_hugepage_on_freelist(struct page *hpage)
2963 struct hstate *h = page_hstate(hpage);
2964 int nid = page_to_nid(hpage);
2966 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
2972 #ifdef CONFIG_MEMORY_FAILURE
2974 * This function is called from memory failure code.
2975 * Assume the caller holds page lock of the head page.
2977 int dequeue_hwpoisoned_huge_page(struct page *hpage)
2979 struct hstate *h = page_hstate(hpage);
2980 int nid = page_to_nid(hpage);
2983 spin_lock(&hugetlb_lock);
2984 if (is_hugepage_on_freelist(hpage)) {
2985 list_del(&hpage->lru);
2986 h->free_huge_pages--;
2987 h->free_huge_pages_node[nid]--;
2990 spin_unlock(&hugetlb_lock);