Merge branch 'for-3.2' of git://linux-nfs.org/~bfields/linux
[linux-btrfs-devel.git] / mm / hugetlb.c
blobdae27ba3be2c8523cd032ad330e2f5a32fbffaf3
1 /*
2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
4 */
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
8 #include <linux/mm.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>
25 #include <asm/page.h>
26 #include <asm/pgtable.h>
27 #include <linux/io.h>
29 #include <linux/hugetlb.h>
30 #include <linux/node.h>
31 #include "internal.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);
66 * or
67 * down_read(&mm->mmap_sem);
68 * mutex_lock(&hugetlb_instantiation_mutex);
70 struct file_region {
71 struct list_head link;
72 long from;
73 long to;
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)
82 if (f <= rg->to)
83 break;
85 /* Round our left edge to the current segment if it encloses us. */
86 if (f > rg->from)
87 f = rg->from;
89 /* Check for and consume any regions we now overlap with. */
90 nrg = rg;
91 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
92 if (&rg->link == head)
93 break;
94 if (rg->from > t)
95 break;
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. */
100 if (rg->to > t)
101 t = rg->to;
102 if (rg != nrg) {
103 list_del(&rg->link);
104 kfree(rg);
107 nrg->from = f;
108 nrg->to = t;
109 return 0;
112 static long region_chg(struct list_head *head, long f, long t)
114 struct file_region *rg, *nrg;
115 long chg = 0;
117 /* Locate the region we are before or in. */
118 list_for_each_entry(rg, head, link)
119 if (f <= rg->to)
120 break;
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);
127 if (!nrg)
128 return -ENOMEM;
129 nrg->from = f;
130 nrg->to = f;
131 INIT_LIST_HEAD(&nrg->link);
132 list_add(&nrg->link, rg->link.prev);
134 return t - f;
137 /* Round our left edge to the current segment if it encloses us. */
138 if (f > rg->from)
139 f = rg->from;
140 chg = t - f;
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)
145 break;
146 if (rg->from > t)
147 return chg;
149 /* We overlap with this area, if it extends further than
150 * us then we must extend ourselves. Account for its
151 * existing reservation. */
152 if (rg->to > t) {
153 chg += rg->to - t;
154 t = rg->to;
156 chg -= rg->to - rg->from;
158 return chg;
161 static long region_truncate(struct list_head *head, long end)
163 struct file_region *rg, *trg;
164 long chg = 0;
166 /* Locate the region we are either in or before. */
167 list_for_each_entry(rg, head, link)
168 if (end <= rg->to)
169 break;
170 if (&rg->link == head)
171 return 0;
173 /* If we are in the middle of a region then adjust it. */
174 if (end > rg->from) {
175 chg = rg->to - end;
176 rg->to = end;
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)
183 break;
184 chg += rg->to - rg->from;
185 list_del(&rg->link);
186 kfree(rg);
188 return chg;
191 static long region_count(struct list_head *head, long f, long t)
193 struct file_region *rg;
194 long chg = 0;
196 /* Locate each segment we overlap with, and count that overlap. */
197 list_for_each_entry(rg, head, link) {
198 int seg_from;
199 int seg_to;
201 if (rg->to <= f)
202 continue;
203 if (rg->from >= t)
204 break;
206 seg_from = max(rg->from, f);
207 seg_to = min(rg->to, t);
209 chg += seg_to - seg_from;
212 return chg;
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))
241 return PAGE_SIZE;
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);
260 #endif
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
265 * alignment.
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,
296 unsigned long value)
298 vma->vm_private_data = (void *)value;
301 struct resv_map {
302 struct kref refs;
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);
309 if (!resv_map)
310 return NULL;
312 kref_init(&resv_map->refs);
313 INIT_LIST_HEAD(&resv_map->regions);
315 return resv_map;
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);
324 kfree(resv_map);
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) &
332 ~HPAGE_RESV_MASK);
333 return NULL;
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)
365 return;
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
373 * private mappings.
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)
391 return 1;
392 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
393 return 1;
394 return 0;
397 static void copy_gigantic_page(struct page *dst, struct page *src)
399 int i;
400 struct hstate *h = page_hstate(src);
401 struct page *dst_base = dst;
402 struct page *src_base = src;
404 for (i = 0; i < pages_per_huge_page(h); ) {
405 cond_resched();
406 copy_highpage(dst, src);
408 i++;
409 dst = mem_map_next(dst, dst_base, i);
410 src = mem_map_next(src, src_base, i);
414 void copy_huge_page(struct page *dst, struct page *src)
416 int i;
417 struct hstate *h = page_hstate(src);
419 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
420 copy_gigantic_page(dst, src);
421 return;
424 might_sleep();
425 for (i = 0; i < pages_per_huge_page(h); i++) {
426 cond_resched();
427 copy_highpage(dst + i, src + i);
431 static void enqueue_huge_page(struct hstate *h, struct page *page)
433 int nid = page_to_nid(page);
434 list_add(&page->lru, &h->hugepage_freelists[nid]);
435 h->free_huge_pages++;
436 h->free_huge_pages_node[nid]++;
439 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
441 struct page *page;
443 if (list_empty(&h->hugepage_freelists[nid]))
444 return NULL;
445 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
446 list_del(&page->lru);
447 set_page_refcounted(page);
448 h->free_huge_pages--;
449 h->free_huge_pages_node[nid]--;
450 return page;
453 static struct page *dequeue_huge_page_vma(struct hstate *h,
454 struct vm_area_struct *vma,
455 unsigned long address, int avoid_reserve)
457 struct page *page = NULL;
458 struct mempolicy *mpol;
459 nodemask_t *nodemask;
460 struct zonelist *zonelist;
461 struct zone *zone;
462 struct zoneref *z;
464 get_mems_allowed();
465 zonelist = huge_zonelist(vma, address,
466 htlb_alloc_mask, &mpol, &nodemask);
468 * A child process with MAP_PRIVATE mappings created by their parent
469 * have no page reserves. This check ensures that reservations are
470 * not "stolen". The child may still get SIGKILLed
472 if (!vma_has_reserves(vma) &&
473 h->free_huge_pages - h->resv_huge_pages == 0)
474 goto err;
476 /* If reserves cannot be used, ensure enough pages are in the pool */
477 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
478 goto err;
480 for_each_zone_zonelist_nodemask(zone, z, zonelist,
481 MAX_NR_ZONES - 1, nodemask) {
482 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
483 page = dequeue_huge_page_node(h, zone_to_nid(zone));
484 if (page) {
485 if (!avoid_reserve)
486 decrement_hugepage_resv_vma(h, vma);
487 break;
491 err:
492 mpol_cond_put(mpol);
493 put_mems_allowed();
494 return page;
497 static void update_and_free_page(struct hstate *h, struct page *page)
499 int i;
501 VM_BUG_ON(h->order >= MAX_ORDER);
503 h->nr_huge_pages--;
504 h->nr_huge_pages_node[page_to_nid(page)]--;
505 for (i = 0; i < pages_per_huge_page(h); i++) {
506 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
507 1 << PG_referenced | 1 << PG_dirty |
508 1 << PG_active | 1 << PG_reserved |
509 1 << PG_private | 1 << PG_writeback);
511 set_compound_page_dtor(page, NULL);
512 set_page_refcounted(page);
513 arch_release_hugepage(page);
514 __free_pages(page, huge_page_order(h));
517 struct hstate *size_to_hstate(unsigned long size)
519 struct hstate *h;
521 for_each_hstate(h) {
522 if (huge_page_size(h) == size)
523 return h;
525 return NULL;
528 static void free_huge_page(struct page *page)
531 * Can't pass hstate in here because it is called from the
532 * compound page destructor.
534 struct hstate *h = page_hstate(page);
535 int nid = page_to_nid(page);
536 struct address_space *mapping;
538 mapping = (struct address_space *) page_private(page);
539 set_page_private(page, 0);
540 page->mapping = NULL;
541 BUG_ON(page_count(page));
542 BUG_ON(page_mapcount(page));
543 INIT_LIST_HEAD(&page->lru);
545 spin_lock(&hugetlb_lock);
546 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
547 update_and_free_page(h, page);
548 h->surplus_huge_pages--;
549 h->surplus_huge_pages_node[nid]--;
550 } else {
551 enqueue_huge_page(h, page);
553 spin_unlock(&hugetlb_lock);
554 if (mapping)
555 hugetlb_put_quota(mapping, 1);
558 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
560 set_compound_page_dtor(page, free_huge_page);
561 spin_lock(&hugetlb_lock);
562 h->nr_huge_pages++;
563 h->nr_huge_pages_node[nid]++;
564 spin_unlock(&hugetlb_lock);
565 put_page(page); /* free it into the hugepage allocator */
568 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
570 int i;
571 int nr_pages = 1 << order;
572 struct page *p = page + 1;
574 /* we rely on prep_new_huge_page to set the destructor */
575 set_compound_order(page, order);
576 __SetPageHead(page);
577 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
578 __SetPageTail(p);
579 p->first_page = page;
583 int PageHuge(struct page *page)
585 compound_page_dtor *dtor;
587 if (!PageCompound(page))
588 return 0;
590 page = compound_head(page);
591 dtor = get_compound_page_dtor(page);
593 return dtor == free_huge_page;
595 EXPORT_SYMBOL_GPL(PageHuge);
597 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
599 struct page *page;
601 if (h->order >= MAX_ORDER)
602 return NULL;
604 page = alloc_pages_exact_node(nid,
605 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
606 __GFP_REPEAT|__GFP_NOWARN,
607 huge_page_order(h));
608 if (page) {
609 if (arch_prepare_hugepage(page)) {
610 __free_pages(page, huge_page_order(h));
611 return NULL;
613 prep_new_huge_page(h, page, nid);
616 return page;
620 * common helper functions for hstate_next_node_to_{alloc|free}.
621 * We may have allocated or freed a huge page based on a different
622 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
623 * be outside of *nodes_allowed. Ensure that we use an allowed
624 * node for alloc or free.
626 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
628 nid = next_node(nid, *nodes_allowed);
629 if (nid == MAX_NUMNODES)
630 nid = first_node(*nodes_allowed);
631 VM_BUG_ON(nid >= MAX_NUMNODES);
633 return nid;
636 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
638 if (!node_isset(nid, *nodes_allowed))
639 nid = next_node_allowed(nid, nodes_allowed);
640 return nid;
644 * returns the previously saved node ["this node"] from which to
645 * allocate a persistent huge page for the pool and advance the
646 * next node from which to allocate, handling wrap at end of node
647 * mask.
649 static int hstate_next_node_to_alloc(struct hstate *h,
650 nodemask_t *nodes_allowed)
652 int nid;
654 VM_BUG_ON(!nodes_allowed);
656 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
657 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
659 return nid;
662 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
664 struct page *page;
665 int start_nid;
666 int next_nid;
667 int ret = 0;
669 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
670 next_nid = start_nid;
672 do {
673 page = alloc_fresh_huge_page_node(h, next_nid);
674 if (page) {
675 ret = 1;
676 break;
678 next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
679 } while (next_nid != start_nid);
681 if (ret)
682 count_vm_event(HTLB_BUDDY_PGALLOC);
683 else
684 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
686 return ret;
690 * helper for free_pool_huge_page() - return the previously saved
691 * node ["this node"] from which to free a huge page. Advance the
692 * next node id whether or not we find a free huge page to free so
693 * that the next attempt to free addresses the next node.
695 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
697 int nid;
699 VM_BUG_ON(!nodes_allowed);
701 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
702 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
704 return nid;
708 * Free huge page from pool from next node to free.
709 * Attempt to keep persistent huge pages more or less
710 * balanced over allowed nodes.
711 * Called with hugetlb_lock locked.
713 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
714 bool acct_surplus)
716 int start_nid;
717 int next_nid;
718 int ret = 0;
720 start_nid = hstate_next_node_to_free(h, nodes_allowed);
721 next_nid = start_nid;
723 do {
725 * If we're returning unused surplus pages, only examine
726 * nodes with surplus pages.
728 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
729 !list_empty(&h->hugepage_freelists[next_nid])) {
730 struct page *page =
731 list_entry(h->hugepage_freelists[next_nid].next,
732 struct page, lru);
733 list_del(&page->lru);
734 h->free_huge_pages--;
735 h->free_huge_pages_node[next_nid]--;
736 if (acct_surplus) {
737 h->surplus_huge_pages--;
738 h->surplus_huge_pages_node[next_nid]--;
740 update_and_free_page(h, page);
741 ret = 1;
742 break;
744 next_nid = hstate_next_node_to_free(h, nodes_allowed);
745 } while (next_nid != start_nid);
747 return ret;
750 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
752 struct page *page;
753 unsigned int r_nid;
755 if (h->order >= MAX_ORDER)
756 return NULL;
759 * Assume we will successfully allocate the surplus page to
760 * prevent racing processes from causing the surplus to exceed
761 * overcommit
763 * This however introduces a different race, where a process B
764 * tries to grow the static hugepage pool while alloc_pages() is
765 * called by process A. B will only examine the per-node
766 * counters in determining if surplus huge pages can be
767 * converted to normal huge pages in adjust_pool_surplus(). A
768 * won't be able to increment the per-node counter, until the
769 * lock is dropped by B, but B doesn't drop hugetlb_lock until
770 * no more huge pages can be converted from surplus to normal
771 * state (and doesn't try to convert again). Thus, we have a
772 * case where a surplus huge page exists, the pool is grown, and
773 * the surplus huge page still exists after, even though it
774 * should just have been converted to a normal huge page. This
775 * does not leak memory, though, as the hugepage will be freed
776 * once it is out of use. It also does not allow the counters to
777 * go out of whack in adjust_pool_surplus() as we don't modify
778 * the node values until we've gotten the hugepage and only the
779 * per-node value is checked there.
781 spin_lock(&hugetlb_lock);
782 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
783 spin_unlock(&hugetlb_lock);
784 return NULL;
785 } else {
786 h->nr_huge_pages++;
787 h->surplus_huge_pages++;
789 spin_unlock(&hugetlb_lock);
791 if (nid == NUMA_NO_NODE)
792 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
793 __GFP_REPEAT|__GFP_NOWARN,
794 huge_page_order(h));
795 else
796 page = alloc_pages_exact_node(nid,
797 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
798 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
800 if (page && arch_prepare_hugepage(page)) {
801 __free_pages(page, huge_page_order(h));
802 return NULL;
805 spin_lock(&hugetlb_lock);
806 if (page) {
807 r_nid = page_to_nid(page);
808 set_compound_page_dtor(page, free_huge_page);
810 * We incremented the global counters already
812 h->nr_huge_pages_node[r_nid]++;
813 h->surplus_huge_pages_node[r_nid]++;
814 __count_vm_event(HTLB_BUDDY_PGALLOC);
815 } else {
816 h->nr_huge_pages--;
817 h->surplus_huge_pages--;
818 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
820 spin_unlock(&hugetlb_lock);
822 return page;
826 * This allocation function is useful in the context where vma is irrelevant.
827 * E.g. soft-offlining uses this function because it only cares physical
828 * address of error page.
830 struct page *alloc_huge_page_node(struct hstate *h, int nid)
832 struct page *page;
834 spin_lock(&hugetlb_lock);
835 page = dequeue_huge_page_node(h, nid);
836 spin_unlock(&hugetlb_lock);
838 if (!page)
839 page = alloc_buddy_huge_page(h, nid);
841 return page;
845 * Increase the hugetlb pool such that it can accommodate a reservation
846 * of size 'delta'.
848 static int gather_surplus_pages(struct hstate *h, int delta)
850 struct list_head surplus_list;
851 struct page *page, *tmp;
852 int ret, i;
853 int needed, allocated;
855 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
856 if (needed <= 0) {
857 h->resv_huge_pages += delta;
858 return 0;
861 allocated = 0;
862 INIT_LIST_HEAD(&surplus_list);
864 ret = -ENOMEM;
865 retry:
866 spin_unlock(&hugetlb_lock);
867 for (i = 0; i < needed; i++) {
868 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
869 if (!page)
871 * We were not able to allocate enough pages to
872 * satisfy the entire reservation so we free what
873 * we've allocated so far.
875 goto free;
877 list_add(&page->lru, &surplus_list);
879 allocated += needed;
882 * After retaking hugetlb_lock, we need to recalculate 'needed'
883 * because either resv_huge_pages or free_huge_pages may have changed.
885 spin_lock(&hugetlb_lock);
886 needed = (h->resv_huge_pages + delta) -
887 (h->free_huge_pages + allocated);
888 if (needed > 0)
889 goto retry;
892 * The surplus_list now contains _at_least_ the number of extra pages
893 * needed to accommodate the reservation. Add the appropriate number
894 * of pages to the hugetlb pool and free the extras back to the buddy
895 * allocator. Commit the entire reservation here to prevent another
896 * process from stealing the pages as they are added to the pool but
897 * before they are reserved.
899 needed += allocated;
900 h->resv_huge_pages += delta;
901 ret = 0;
903 spin_unlock(&hugetlb_lock);
904 /* Free the needed pages to the hugetlb pool */
905 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
906 if ((--needed) < 0)
907 break;
908 list_del(&page->lru);
910 * This page is now managed by the hugetlb allocator and has
911 * no users -- drop the buddy allocator's reference.
913 put_page_testzero(page);
914 VM_BUG_ON(page_count(page));
915 enqueue_huge_page(h, page);
918 /* Free unnecessary surplus pages to the buddy allocator */
919 free:
920 if (!list_empty(&surplus_list)) {
921 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
922 list_del(&page->lru);
923 put_page(page);
926 spin_lock(&hugetlb_lock);
928 return ret;
932 * When releasing a hugetlb pool reservation, any surplus pages that were
933 * allocated to satisfy the reservation must be explicitly freed if they were
934 * never used.
935 * Called with hugetlb_lock held.
937 static void return_unused_surplus_pages(struct hstate *h,
938 unsigned long unused_resv_pages)
940 unsigned long nr_pages;
942 /* Uncommit the reservation */
943 h->resv_huge_pages -= unused_resv_pages;
945 /* Cannot return gigantic pages currently */
946 if (h->order >= MAX_ORDER)
947 return;
949 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
952 * We want to release as many surplus pages as possible, spread
953 * evenly across all nodes with memory. Iterate across these nodes
954 * until we can no longer free unreserved surplus pages. This occurs
955 * when the nodes with surplus pages have no free pages.
956 * free_pool_huge_page() will balance the the freed pages across the
957 * on-line nodes with memory and will handle the hstate accounting.
959 while (nr_pages--) {
960 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
961 break;
966 * Determine if the huge page at addr within the vma has an associated
967 * reservation. Where it does not we will need to logically increase
968 * reservation and actually increase quota before an allocation can occur.
969 * Where any new reservation would be required the reservation change is
970 * prepared, but not committed. Once the page has been quota'd allocated
971 * an instantiated the change should be committed via vma_commit_reservation.
972 * No action is required on failure.
974 static long vma_needs_reservation(struct hstate *h,
975 struct vm_area_struct *vma, unsigned long addr)
977 struct address_space *mapping = vma->vm_file->f_mapping;
978 struct inode *inode = mapping->host;
980 if (vma->vm_flags & VM_MAYSHARE) {
981 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
982 return region_chg(&inode->i_mapping->private_list,
983 idx, idx + 1);
985 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
986 return 1;
988 } else {
989 long err;
990 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
991 struct resv_map *reservations = vma_resv_map(vma);
993 err = region_chg(&reservations->regions, idx, idx + 1);
994 if (err < 0)
995 return err;
996 return 0;
999 static void vma_commit_reservation(struct hstate *h,
1000 struct vm_area_struct *vma, unsigned long addr)
1002 struct address_space *mapping = vma->vm_file->f_mapping;
1003 struct inode *inode = mapping->host;
1005 if (vma->vm_flags & VM_MAYSHARE) {
1006 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1007 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1009 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1010 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1011 struct resv_map *reservations = vma_resv_map(vma);
1013 /* Mark this page used in the map. */
1014 region_add(&reservations->regions, idx, idx + 1);
1018 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1019 unsigned long addr, int avoid_reserve)
1021 struct hstate *h = hstate_vma(vma);
1022 struct page *page;
1023 struct address_space *mapping = vma->vm_file->f_mapping;
1024 struct inode *inode = mapping->host;
1025 long chg;
1028 * Processes that did not create the mapping will have no reserves and
1029 * will not have accounted against quota. Check that the quota can be
1030 * made before satisfying the allocation
1031 * MAP_NORESERVE mappings may also need pages and quota allocated
1032 * if no reserve mapping overlaps.
1034 chg = vma_needs_reservation(h, vma, addr);
1035 if (chg < 0)
1036 return ERR_PTR(-VM_FAULT_OOM);
1037 if (chg)
1038 if (hugetlb_get_quota(inode->i_mapping, chg))
1039 return ERR_PTR(-VM_FAULT_SIGBUS);
1041 spin_lock(&hugetlb_lock);
1042 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1043 spin_unlock(&hugetlb_lock);
1045 if (!page) {
1046 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1047 if (!page) {
1048 hugetlb_put_quota(inode->i_mapping, chg);
1049 return ERR_PTR(-VM_FAULT_SIGBUS);
1053 set_page_private(page, (unsigned long) mapping);
1055 vma_commit_reservation(h, vma, addr);
1057 return page;
1060 int __weak alloc_bootmem_huge_page(struct hstate *h)
1062 struct huge_bootmem_page *m;
1063 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1065 while (nr_nodes) {
1066 void *addr;
1068 addr = __alloc_bootmem_node_nopanic(
1069 NODE_DATA(hstate_next_node_to_alloc(h,
1070 &node_states[N_HIGH_MEMORY])),
1071 huge_page_size(h), huge_page_size(h), 0);
1073 if (addr) {
1075 * Use the beginning of the huge page to store the
1076 * huge_bootmem_page struct (until gather_bootmem
1077 * puts them into the mem_map).
1079 m = addr;
1080 goto found;
1082 nr_nodes--;
1084 return 0;
1086 found:
1087 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1088 /* Put them into a private list first because mem_map is not up yet */
1089 list_add(&m->list, &huge_boot_pages);
1090 m->hstate = h;
1091 return 1;
1094 static void prep_compound_huge_page(struct page *page, int order)
1096 if (unlikely(order > (MAX_ORDER - 1)))
1097 prep_compound_gigantic_page(page, order);
1098 else
1099 prep_compound_page(page, order);
1102 /* Put bootmem huge pages into the standard lists after mem_map is up */
1103 static void __init gather_bootmem_prealloc(void)
1105 struct huge_bootmem_page *m;
1107 list_for_each_entry(m, &huge_boot_pages, list) {
1108 struct hstate *h = m->hstate;
1109 struct page *page;
1111 #ifdef CONFIG_HIGHMEM
1112 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1113 free_bootmem_late((unsigned long)m,
1114 sizeof(struct huge_bootmem_page));
1115 #else
1116 page = virt_to_page(m);
1117 #endif
1118 __ClearPageReserved(page);
1119 WARN_ON(page_count(page) != 1);
1120 prep_compound_huge_page(page, h->order);
1121 prep_new_huge_page(h, page, page_to_nid(page));
1123 * If we had gigantic hugepages allocated at boot time, we need
1124 * to restore the 'stolen' pages to totalram_pages in order to
1125 * fix confusing memory reports from free(1) and another
1126 * side-effects, like CommitLimit going negative.
1128 if (h->order > (MAX_ORDER - 1))
1129 totalram_pages += 1 << h->order;
1133 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1135 unsigned long i;
1137 for (i = 0; i < h->max_huge_pages; ++i) {
1138 if (h->order >= MAX_ORDER) {
1139 if (!alloc_bootmem_huge_page(h))
1140 break;
1141 } else if (!alloc_fresh_huge_page(h,
1142 &node_states[N_HIGH_MEMORY]))
1143 break;
1145 h->max_huge_pages = i;
1148 static void __init hugetlb_init_hstates(void)
1150 struct hstate *h;
1152 for_each_hstate(h) {
1153 /* oversize hugepages were init'ed in early boot */
1154 if (h->order < MAX_ORDER)
1155 hugetlb_hstate_alloc_pages(h);
1159 static char * __init memfmt(char *buf, unsigned long n)
1161 if (n >= (1UL << 30))
1162 sprintf(buf, "%lu GB", n >> 30);
1163 else if (n >= (1UL << 20))
1164 sprintf(buf, "%lu MB", n >> 20);
1165 else
1166 sprintf(buf, "%lu KB", n >> 10);
1167 return buf;
1170 static void __init report_hugepages(void)
1172 struct hstate *h;
1174 for_each_hstate(h) {
1175 char buf[32];
1176 printk(KERN_INFO "HugeTLB registered %s page size, "
1177 "pre-allocated %ld pages\n",
1178 memfmt(buf, huge_page_size(h)),
1179 h->free_huge_pages);
1183 #ifdef CONFIG_HIGHMEM
1184 static void try_to_free_low(struct hstate *h, unsigned long count,
1185 nodemask_t *nodes_allowed)
1187 int i;
1189 if (h->order >= MAX_ORDER)
1190 return;
1192 for_each_node_mask(i, *nodes_allowed) {
1193 struct page *page, *next;
1194 struct list_head *freel = &h->hugepage_freelists[i];
1195 list_for_each_entry_safe(page, next, freel, lru) {
1196 if (count >= h->nr_huge_pages)
1197 return;
1198 if (PageHighMem(page))
1199 continue;
1200 list_del(&page->lru);
1201 update_and_free_page(h, page);
1202 h->free_huge_pages--;
1203 h->free_huge_pages_node[page_to_nid(page)]--;
1207 #else
1208 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1209 nodemask_t *nodes_allowed)
1212 #endif
1215 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1216 * balanced by operating on them in a round-robin fashion.
1217 * Returns 1 if an adjustment was made.
1219 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1220 int delta)
1222 int start_nid, next_nid;
1223 int ret = 0;
1225 VM_BUG_ON(delta != -1 && delta != 1);
1227 if (delta < 0)
1228 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1229 else
1230 start_nid = hstate_next_node_to_free(h, nodes_allowed);
1231 next_nid = start_nid;
1233 do {
1234 int nid = next_nid;
1235 if (delta < 0) {
1237 * To shrink on this node, there must be a surplus page
1239 if (!h->surplus_huge_pages_node[nid]) {
1240 next_nid = hstate_next_node_to_alloc(h,
1241 nodes_allowed);
1242 continue;
1245 if (delta > 0) {
1247 * Surplus cannot exceed the total number of pages
1249 if (h->surplus_huge_pages_node[nid] >=
1250 h->nr_huge_pages_node[nid]) {
1251 next_nid = hstate_next_node_to_free(h,
1252 nodes_allowed);
1253 continue;
1257 h->surplus_huge_pages += delta;
1258 h->surplus_huge_pages_node[nid] += delta;
1259 ret = 1;
1260 break;
1261 } while (next_nid != start_nid);
1263 return ret;
1266 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1267 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1268 nodemask_t *nodes_allowed)
1270 unsigned long min_count, ret;
1272 if (h->order >= MAX_ORDER)
1273 return h->max_huge_pages;
1276 * Increase the pool size
1277 * First take pages out of surplus state. Then make up the
1278 * remaining difference by allocating fresh huge pages.
1280 * We might race with alloc_buddy_huge_page() here and be unable
1281 * to convert a surplus huge page to a normal huge page. That is
1282 * not critical, though, it just means the overall size of the
1283 * pool might be one hugepage larger than it needs to be, but
1284 * within all the constraints specified by the sysctls.
1286 spin_lock(&hugetlb_lock);
1287 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1288 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1289 break;
1292 while (count > persistent_huge_pages(h)) {
1294 * If this allocation races such that we no longer need the
1295 * page, free_huge_page will handle it by freeing the page
1296 * and reducing the surplus.
1298 spin_unlock(&hugetlb_lock);
1299 ret = alloc_fresh_huge_page(h, nodes_allowed);
1300 spin_lock(&hugetlb_lock);
1301 if (!ret)
1302 goto out;
1304 /* Bail for signals. Probably ctrl-c from user */
1305 if (signal_pending(current))
1306 goto out;
1310 * Decrease the pool size
1311 * First return free pages to the buddy allocator (being careful
1312 * to keep enough around to satisfy reservations). Then place
1313 * pages into surplus state as needed so the pool will shrink
1314 * to the desired size as pages become free.
1316 * By placing pages into the surplus state independent of the
1317 * overcommit value, we are allowing the surplus pool size to
1318 * exceed overcommit. There are few sane options here. Since
1319 * alloc_buddy_huge_page() is checking the global counter,
1320 * though, we'll note that we're not allowed to exceed surplus
1321 * and won't grow the pool anywhere else. Not until one of the
1322 * sysctls are changed, or the surplus pages go out of use.
1324 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1325 min_count = max(count, min_count);
1326 try_to_free_low(h, min_count, nodes_allowed);
1327 while (min_count < persistent_huge_pages(h)) {
1328 if (!free_pool_huge_page(h, nodes_allowed, 0))
1329 break;
1331 while (count < persistent_huge_pages(h)) {
1332 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1333 break;
1335 out:
1336 ret = persistent_huge_pages(h);
1337 spin_unlock(&hugetlb_lock);
1338 return ret;
1341 #define HSTATE_ATTR_RO(_name) \
1342 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1344 #define HSTATE_ATTR(_name) \
1345 static struct kobj_attribute _name##_attr = \
1346 __ATTR(_name, 0644, _name##_show, _name##_store)
1348 static struct kobject *hugepages_kobj;
1349 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1351 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1353 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1355 int i;
1357 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1358 if (hstate_kobjs[i] == kobj) {
1359 if (nidp)
1360 *nidp = NUMA_NO_NODE;
1361 return &hstates[i];
1364 return kobj_to_node_hstate(kobj, nidp);
1367 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1368 struct kobj_attribute *attr, char *buf)
1370 struct hstate *h;
1371 unsigned long nr_huge_pages;
1372 int nid;
1374 h = kobj_to_hstate(kobj, &nid);
1375 if (nid == NUMA_NO_NODE)
1376 nr_huge_pages = h->nr_huge_pages;
1377 else
1378 nr_huge_pages = h->nr_huge_pages_node[nid];
1380 return sprintf(buf, "%lu\n", nr_huge_pages);
1383 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1384 struct kobject *kobj, struct kobj_attribute *attr,
1385 const char *buf, size_t len)
1387 int err;
1388 int nid;
1389 unsigned long count;
1390 struct hstate *h;
1391 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1393 err = strict_strtoul(buf, 10, &count);
1394 if (err)
1395 goto out;
1397 h = kobj_to_hstate(kobj, &nid);
1398 if (h->order >= MAX_ORDER) {
1399 err = -EINVAL;
1400 goto out;
1403 if (nid == NUMA_NO_NODE) {
1405 * global hstate attribute
1407 if (!(obey_mempolicy &&
1408 init_nodemask_of_mempolicy(nodes_allowed))) {
1409 NODEMASK_FREE(nodes_allowed);
1410 nodes_allowed = &node_states[N_HIGH_MEMORY];
1412 } else if (nodes_allowed) {
1414 * per node hstate attribute: adjust count to global,
1415 * but restrict alloc/free to the specified node.
1417 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1418 init_nodemask_of_node(nodes_allowed, nid);
1419 } else
1420 nodes_allowed = &node_states[N_HIGH_MEMORY];
1422 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1424 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1425 NODEMASK_FREE(nodes_allowed);
1427 return len;
1428 out:
1429 NODEMASK_FREE(nodes_allowed);
1430 return err;
1433 static ssize_t nr_hugepages_show(struct kobject *kobj,
1434 struct kobj_attribute *attr, char *buf)
1436 return nr_hugepages_show_common(kobj, attr, buf);
1439 static ssize_t nr_hugepages_store(struct kobject *kobj,
1440 struct kobj_attribute *attr, const char *buf, size_t len)
1442 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1444 HSTATE_ATTR(nr_hugepages);
1446 #ifdef CONFIG_NUMA
1449 * hstate attribute for optionally mempolicy-based constraint on persistent
1450 * huge page alloc/free.
1452 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1453 struct kobj_attribute *attr, char *buf)
1455 return nr_hugepages_show_common(kobj, attr, buf);
1458 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1459 struct kobj_attribute *attr, const char *buf, size_t len)
1461 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1463 HSTATE_ATTR(nr_hugepages_mempolicy);
1464 #endif
1467 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1468 struct kobj_attribute *attr, char *buf)
1470 struct hstate *h = kobj_to_hstate(kobj, NULL);
1471 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1474 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1475 struct kobj_attribute *attr, const char *buf, size_t count)
1477 int err;
1478 unsigned long input;
1479 struct hstate *h = kobj_to_hstate(kobj, NULL);
1481 if (h->order >= MAX_ORDER)
1482 return -EINVAL;
1484 err = strict_strtoul(buf, 10, &input);
1485 if (err)
1486 return err;
1488 spin_lock(&hugetlb_lock);
1489 h->nr_overcommit_huge_pages = input;
1490 spin_unlock(&hugetlb_lock);
1492 return count;
1494 HSTATE_ATTR(nr_overcommit_hugepages);
1496 static ssize_t free_hugepages_show(struct kobject *kobj,
1497 struct kobj_attribute *attr, char *buf)
1499 struct hstate *h;
1500 unsigned long free_huge_pages;
1501 int nid;
1503 h = kobj_to_hstate(kobj, &nid);
1504 if (nid == NUMA_NO_NODE)
1505 free_huge_pages = h->free_huge_pages;
1506 else
1507 free_huge_pages = h->free_huge_pages_node[nid];
1509 return sprintf(buf, "%lu\n", free_huge_pages);
1511 HSTATE_ATTR_RO(free_hugepages);
1513 static ssize_t resv_hugepages_show(struct kobject *kobj,
1514 struct kobj_attribute *attr, char *buf)
1516 struct hstate *h = kobj_to_hstate(kobj, NULL);
1517 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1519 HSTATE_ATTR_RO(resv_hugepages);
1521 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1522 struct kobj_attribute *attr, char *buf)
1524 struct hstate *h;
1525 unsigned long surplus_huge_pages;
1526 int nid;
1528 h = kobj_to_hstate(kobj, &nid);
1529 if (nid == NUMA_NO_NODE)
1530 surplus_huge_pages = h->surplus_huge_pages;
1531 else
1532 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1534 return sprintf(buf, "%lu\n", surplus_huge_pages);
1536 HSTATE_ATTR_RO(surplus_hugepages);
1538 static struct attribute *hstate_attrs[] = {
1539 &nr_hugepages_attr.attr,
1540 &nr_overcommit_hugepages_attr.attr,
1541 &free_hugepages_attr.attr,
1542 &resv_hugepages_attr.attr,
1543 &surplus_hugepages_attr.attr,
1544 #ifdef CONFIG_NUMA
1545 &nr_hugepages_mempolicy_attr.attr,
1546 #endif
1547 NULL,
1550 static struct attribute_group hstate_attr_group = {
1551 .attrs = hstate_attrs,
1554 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1555 struct kobject **hstate_kobjs,
1556 struct attribute_group *hstate_attr_group)
1558 int retval;
1559 int hi = h - hstates;
1561 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1562 if (!hstate_kobjs[hi])
1563 return -ENOMEM;
1565 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1566 if (retval)
1567 kobject_put(hstate_kobjs[hi]);
1569 return retval;
1572 static void __init hugetlb_sysfs_init(void)
1574 struct hstate *h;
1575 int err;
1577 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1578 if (!hugepages_kobj)
1579 return;
1581 for_each_hstate(h) {
1582 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1583 hstate_kobjs, &hstate_attr_group);
1584 if (err)
1585 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1586 h->name);
1590 #ifdef CONFIG_NUMA
1593 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1594 * with node sysdevs in node_devices[] using a parallel array. The array
1595 * index of a node sysdev or _hstate == node id.
1596 * This is here to avoid any static dependency of the node sysdev driver, in
1597 * the base kernel, on the hugetlb module.
1599 struct node_hstate {
1600 struct kobject *hugepages_kobj;
1601 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1603 struct node_hstate node_hstates[MAX_NUMNODES];
1606 * A subset of global hstate attributes for node sysdevs
1608 static struct attribute *per_node_hstate_attrs[] = {
1609 &nr_hugepages_attr.attr,
1610 &free_hugepages_attr.attr,
1611 &surplus_hugepages_attr.attr,
1612 NULL,
1615 static struct attribute_group per_node_hstate_attr_group = {
1616 .attrs = per_node_hstate_attrs,
1620 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1621 * Returns node id via non-NULL nidp.
1623 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1625 int nid;
1627 for (nid = 0; nid < nr_node_ids; nid++) {
1628 struct node_hstate *nhs = &node_hstates[nid];
1629 int i;
1630 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1631 if (nhs->hstate_kobjs[i] == kobj) {
1632 if (nidp)
1633 *nidp = nid;
1634 return &hstates[i];
1638 BUG();
1639 return NULL;
1643 * Unregister hstate attributes from a single node sysdev.
1644 * No-op if no hstate attributes attached.
1646 void hugetlb_unregister_node(struct node *node)
1648 struct hstate *h;
1649 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1651 if (!nhs->hugepages_kobj)
1652 return; /* no hstate attributes */
1654 for_each_hstate(h)
1655 if (nhs->hstate_kobjs[h - hstates]) {
1656 kobject_put(nhs->hstate_kobjs[h - hstates]);
1657 nhs->hstate_kobjs[h - hstates] = NULL;
1660 kobject_put(nhs->hugepages_kobj);
1661 nhs->hugepages_kobj = NULL;
1665 * hugetlb module exit: unregister hstate attributes from node sysdevs
1666 * that have them.
1668 static void hugetlb_unregister_all_nodes(void)
1670 int nid;
1673 * disable node sysdev registrations.
1675 register_hugetlbfs_with_node(NULL, NULL);
1678 * remove hstate attributes from any nodes that have them.
1680 for (nid = 0; nid < nr_node_ids; nid++)
1681 hugetlb_unregister_node(&node_devices[nid]);
1685 * Register hstate attributes for a single node sysdev.
1686 * No-op if attributes already registered.
1688 void hugetlb_register_node(struct node *node)
1690 struct hstate *h;
1691 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1692 int err;
1694 if (nhs->hugepages_kobj)
1695 return; /* already allocated */
1697 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1698 &node->sysdev.kobj);
1699 if (!nhs->hugepages_kobj)
1700 return;
1702 for_each_hstate(h) {
1703 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1704 nhs->hstate_kobjs,
1705 &per_node_hstate_attr_group);
1706 if (err) {
1707 printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
1708 " for node %d\n",
1709 h->name, node->sysdev.id);
1710 hugetlb_unregister_node(node);
1711 break;
1717 * hugetlb init time: register hstate attributes for all registered node
1718 * sysdevs of nodes that have memory. All on-line nodes should have
1719 * registered their associated sysdev by this time.
1721 static void hugetlb_register_all_nodes(void)
1723 int nid;
1725 for_each_node_state(nid, N_HIGH_MEMORY) {
1726 struct node *node = &node_devices[nid];
1727 if (node->sysdev.id == nid)
1728 hugetlb_register_node(node);
1732 * Let the node sysdev driver know we're here so it can
1733 * [un]register hstate attributes on node hotplug.
1735 register_hugetlbfs_with_node(hugetlb_register_node,
1736 hugetlb_unregister_node);
1738 #else /* !CONFIG_NUMA */
1740 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1742 BUG();
1743 if (nidp)
1744 *nidp = -1;
1745 return NULL;
1748 static void hugetlb_unregister_all_nodes(void) { }
1750 static void hugetlb_register_all_nodes(void) { }
1752 #endif
1754 static void __exit hugetlb_exit(void)
1756 struct hstate *h;
1758 hugetlb_unregister_all_nodes();
1760 for_each_hstate(h) {
1761 kobject_put(hstate_kobjs[h - hstates]);
1764 kobject_put(hugepages_kobj);
1766 module_exit(hugetlb_exit);
1768 static int __init hugetlb_init(void)
1770 /* Some platform decide whether they support huge pages at boot
1771 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1772 * there is no such support
1774 if (HPAGE_SHIFT == 0)
1775 return 0;
1777 if (!size_to_hstate(default_hstate_size)) {
1778 default_hstate_size = HPAGE_SIZE;
1779 if (!size_to_hstate(default_hstate_size))
1780 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1782 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1783 if (default_hstate_max_huge_pages)
1784 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1786 hugetlb_init_hstates();
1788 gather_bootmem_prealloc();
1790 report_hugepages();
1792 hugetlb_sysfs_init();
1794 hugetlb_register_all_nodes();
1796 return 0;
1798 module_init(hugetlb_init);
1800 /* Should be called on processing a hugepagesz=... option */
1801 void __init hugetlb_add_hstate(unsigned order)
1803 struct hstate *h;
1804 unsigned long i;
1806 if (size_to_hstate(PAGE_SIZE << order)) {
1807 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1808 return;
1810 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1811 BUG_ON(order == 0);
1812 h = &hstates[max_hstate++];
1813 h->order = order;
1814 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1815 h->nr_huge_pages = 0;
1816 h->free_huge_pages = 0;
1817 for (i = 0; i < MAX_NUMNODES; ++i)
1818 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1819 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
1820 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1821 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1822 huge_page_size(h)/1024);
1824 parsed_hstate = h;
1827 static int __init hugetlb_nrpages_setup(char *s)
1829 unsigned long *mhp;
1830 static unsigned long *last_mhp;
1833 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1834 * so this hugepages= parameter goes to the "default hstate".
1836 if (!max_hstate)
1837 mhp = &default_hstate_max_huge_pages;
1838 else
1839 mhp = &parsed_hstate->max_huge_pages;
1841 if (mhp == last_mhp) {
1842 printk(KERN_WARNING "hugepages= specified twice without "
1843 "interleaving hugepagesz=, ignoring\n");
1844 return 1;
1847 if (sscanf(s, "%lu", mhp) <= 0)
1848 *mhp = 0;
1851 * Global state is always initialized later in hugetlb_init.
1852 * But we need to allocate >= MAX_ORDER hstates here early to still
1853 * use the bootmem allocator.
1855 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1856 hugetlb_hstate_alloc_pages(parsed_hstate);
1858 last_mhp = mhp;
1860 return 1;
1862 __setup("hugepages=", hugetlb_nrpages_setup);
1864 static int __init hugetlb_default_setup(char *s)
1866 default_hstate_size = memparse(s, &s);
1867 return 1;
1869 __setup("default_hugepagesz=", hugetlb_default_setup);
1871 static unsigned int cpuset_mems_nr(unsigned int *array)
1873 int node;
1874 unsigned int nr = 0;
1876 for_each_node_mask(node, cpuset_current_mems_allowed)
1877 nr += array[node];
1879 return nr;
1882 #ifdef CONFIG_SYSCTL
1883 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
1884 struct ctl_table *table, int write,
1885 void __user *buffer, size_t *length, loff_t *ppos)
1887 struct hstate *h = &default_hstate;
1888 unsigned long tmp;
1889 int ret;
1891 tmp = h->max_huge_pages;
1893 if (write && h->order >= MAX_ORDER)
1894 return -EINVAL;
1896 table->data = &tmp;
1897 table->maxlen = sizeof(unsigned long);
1898 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
1899 if (ret)
1900 goto out;
1902 if (write) {
1903 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
1904 GFP_KERNEL | __GFP_NORETRY);
1905 if (!(obey_mempolicy &&
1906 init_nodemask_of_mempolicy(nodes_allowed))) {
1907 NODEMASK_FREE(nodes_allowed);
1908 nodes_allowed = &node_states[N_HIGH_MEMORY];
1910 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
1912 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1913 NODEMASK_FREE(nodes_allowed);
1915 out:
1916 return ret;
1919 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1920 void __user *buffer, size_t *length, loff_t *ppos)
1923 return hugetlb_sysctl_handler_common(false, table, write,
1924 buffer, length, ppos);
1927 #ifdef CONFIG_NUMA
1928 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
1929 void __user *buffer, size_t *length, loff_t *ppos)
1931 return hugetlb_sysctl_handler_common(true, table, write,
1932 buffer, length, ppos);
1934 #endif /* CONFIG_NUMA */
1936 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1937 void __user *buffer,
1938 size_t *length, loff_t *ppos)
1940 proc_dointvec(table, write, buffer, length, ppos);
1941 if (hugepages_treat_as_movable)
1942 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1943 else
1944 htlb_alloc_mask = GFP_HIGHUSER;
1945 return 0;
1948 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1949 void __user *buffer,
1950 size_t *length, loff_t *ppos)
1952 struct hstate *h = &default_hstate;
1953 unsigned long tmp;
1954 int ret;
1956 tmp = h->nr_overcommit_huge_pages;
1958 if (write && h->order >= MAX_ORDER)
1959 return -EINVAL;
1961 table->data = &tmp;
1962 table->maxlen = sizeof(unsigned long);
1963 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
1964 if (ret)
1965 goto out;
1967 if (write) {
1968 spin_lock(&hugetlb_lock);
1969 h->nr_overcommit_huge_pages = tmp;
1970 spin_unlock(&hugetlb_lock);
1972 out:
1973 return ret;
1976 #endif /* CONFIG_SYSCTL */
1978 void hugetlb_report_meminfo(struct seq_file *m)
1980 struct hstate *h = &default_hstate;
1981 seq_printf(m,
1982 "HugePages_Total: %5lu\n"
1983 "HugePages_Free: %5lu\n"
1984 "HugePages_Rsvd: %5lu\n"
1985 "HugePages_Surp: %5lu\n"
1986 "Hugepagesize: %8lu kB\n",
1987 h->nr_huge_pages,
1988 h->free_huge_pages,
1989 h->resv_huge_pages,
1990 h->surplus_huge_pages,
1991 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1994 int hugetlb_report_node_meminfo(int nid, char *buf)
1996 struct hstate *h = &default_hstate;
1997 return sprintf(buf,
1998 "Node %d HugePages_Total: %5u\n"
1999 "Node %d HugePages_Free: %5u\n"
2000 "Node %d HugePages_Surp: %5u\n",
2001 nid, h->nr_huge_pages_node[nid],
2002 nid, h->free_huge_pages_node[nid],
2003 nid, h->surplus_huge_pages_node[nid]);
2006 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2007 unsigned long hugetlb_total_pages(void)
2009 struct hstate *h = &default_hstate;
2010 return h->nr_huge_pages * pages_per_huge_page(h);
2013 static int hugetlb_acct_memory(struct hstate *h, long delta)
2015 int ret = -ENOMEM;
2017 spin_lock(&hugetlb_lock);
2019 * When cpuset is configured, it breaks the strict hugetlb page
2020 * reservation as the accounting is done on a global variable. Such
2021 * reservation is completely rubbish in the presence of cpuset because
2022 * the reservation is not checked against page availability for the
2023 * current cpuset. Application can still potentially OOM'ed by kernel
2024 * with lack of free htlb page in cpuset that the task is in.
2025 * Attempt to enforce strict accounting with cpuset is almost
2026 * impossible (or too ugly) because cpuset is too fluid that
2027 * task or memory node can be dynamically moved between cpusets.
2029 * The change of semantics for shared hugetlb mapping with cpuset is
2030 * undesirable. However, in order to preserve some of the semantics,
2031 * we fall back to check against current free page availability as
2032 * a best attempt and hopefully to minimize the impact of changing
2033 * semantics that cpuset has.
2035 if (delta > 0) {
2036 if (gather_surplus_pages(h, delta) < 0)
2037 goto out;
2039 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2040 return_unused_surplus_pages(h, delta);
2041 goto out;
2045 ret = 0;
2046 if (delta < 0)
2047 return_unused_surplus_pages(h, (unsigned long) -delta);
2049 out:
2050 spin_unlock(&hugetlb_lock);
2051 return ret;
2054 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2056 struct resv_map *reservations = vma_resv_map(vma);
2059 * This new VMA should share its siblings reservation map if present.
2060 * The VMA will only ever have a valid reservation map pointer where
2061 * it is being copied for another still existing VMA. As that VMA
2062 * has a reference to the reservation map it cannot disappear until
2063 * after this open call completes. It is therefore safe to take a
2064 * new reference here without additional locking.
2066 if (reservations)
2067 kref_get(&reservations->refs);
2070 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2072 struct hstate *h = hstate_vma(vma);
2073 struct resv_map *reservations = vma_resv_map(vma);
2074 unsigned long reserve;
2075 unsigned long start;
2076 unsigned long end;
2078 if (reservations) {
2079 start = vma_hugecache_offset(h, vma, vma->vm_start);
2080 end = vma_hugecache_offset(h, vma, vma->vm_end);
2082 reserve = (end - start) -
2083 region_count(&reservations->regions, start, end);
2085 kref_put(&reservations->refs, resv_map_release);
2087 if (reserve) {
2088 hugetlb_acct_memory(h, -reserve);
2089 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
2095 * We cannot handle pagefaults against hugetlb pages at all. They cause
2096 * handle_mm_fault() to try to instantiate regular-sized pages in the
2097 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2098 * this far.
2100 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2102 BUG();
2103 return 0;
2106 const struct vm_operations_struct hugetlb_vm_ops = {
2107 .fault = hugetlb_vm_op_fault,
2108 .open = hugetlb_vm_op_open,
2109 .close = hugetlb_vm_op_close,
2112 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2113 int writable)
2115 pte_t entry;
2117 if (writable) {
2118 entry =
2119 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
2120 } else {
2121 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
2123 entry = pte_mkyoung(entry);
2124 entry = pte_mkhuge(entry);
2126 return entry;
2129 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2130 unsigned long address, pte_t *ptep)
2132 pte_t entry;
2134 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2135 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2136 update_mmu_cache(vma, address, ptep);
2140 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2141 struct vm_area_struct *vma)
2143 pte_t *src_pte, *dst_pte, entry;
2144 struct page *ptepage;
2145 unsigned long addr;
2146 int cow;
2147 struct hstate *h = hstate_vma(vma);
2148 unsigned long sz = huge_page_size(h);
2150 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2152 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2153 src_pte = huge_pte_offset(src, addr);
2154 if (!src_pte)
2155 continue;
2156 dst_pte = huge_pte_alloc(dst, addr, sz);
2157 if (!dst_pte)
2158 goto nomem;
2160 /* If the pagetables are shared don't copy or take references */
2161 if (dst_pte == src_pte)
2162 continue;
2164 spin_lock(&dst->page_table_lock);
2165 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2166 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2167 if (cow)
2168 huge_ptep_set_wrprotect(src, addr, src_pte);
2169 entry = huge_ptep_get(src_pte);
2170 ptepage = pte_page(entry);
2171 get_page(ptepage);
2172 page_dup_rmap(ptepage);
2173 set_huge_pte_at(dst, addr, dst_pte, entry);
2175 spin_unlock(&src->page_table_lock);
2176 spin_unlock(&dst->page_table_lock);
2178 return 0;
2180 nomem:
2181 return -ENOMEM;
2184 static int is_hugetlb_entry_migration(pte_t pte)
2186 swp_entry_t swp;
2188 if (huge_pte_none(pte) || pte_present(pte))
2189 return 0;
2190 swp = pte_to_swp_entry(pte);
2191 if (non_swap_entry(swp) && is_migration_entry(swp))
2192 return 1;
2193 else
2194 return 0;
2197 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2199 swp_entry_t swp;
2201 if (huge_pte_none(pte) || pte_present(pte))
2202 return 0;
2203 swp = pte_to_swp_entry(pte);
2204 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2205 return 1;
2206 else
2207 return 0;
2210 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2211 unsigned long end, struct page *ref_page)
2213 struct mm_struct *mm = vma->vm_mm;
2214 unsigned long address;
2215 pte_t *ptep;
2216 pte_t pte;
2217 struct page *page;
2218 struct page *tmp;
2219 struct hstate *h = hstate_vma(vma);
2220 unsigned long sz = huge_page_size(h);
2223 * A page gathering list, protected by per file i_mmap_mutex. The
2224 * lock is used to avoid list corruption from multiple unmapping
2225 * of the same page since we are using page->lru.
2227 LIST_HEAD(page_list);
2229 WARN_ON(!is_vm_hugetlb_page(vma));
2230 BUG_ON(start & ~huge_page_mask(h));
2231 BUG_ON(end & ~huge_page_mask(h));
2233 mmu_notifier_invalidate_range_start(mm, start, end);
2234 spin_lock(&mm->page_table_lock);
2235 for (address = start; address < end; address += sz) {
2236 ptep = huge_pte_offset(mm, address);
2237 if (!ptep)
2238 continue;
2240 if (huge_pmd_unshare(mm, &address, ptep))
2241 continue;
2244 * If a reference page is supplied, it is because a specific
2245 * page is being unmapped, not a range. Ensure the page we
2246 * are about to unmap is the actual page of interest.
2248 if (ref_page) {
2249 pte = huge_ptep_get(ptep);
2250 if (huge_pte_none(pte))
2251 continue;
2252 page = pte_page(pte);
2253 if (page != ref_page)
2254 continue;
2257 * Mark the VMA as having unmapped its page so that
2258 * future faults in this VMA will fail rather than
2259 * looking like data was lost
2261 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2264 pte = huge_ptep_get_and_clear(mm, address, ptep);
2265 if (huge_pte_none(pte))
2266 continue;
2269 * HWPoisoned hugepage is already unmapped and dropped reference
2271 if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
2272 continue;
2274 page = pte_page(pte);
2275 if (pte_dirty(pte))
2276 set_page_dirty(page);
2277 list_add(&page->lru, &page_list);
2279 spin_unlock(&mm->page_table_lock);
2280 flush_tlb_range(vma, start, end);
2281 mmu_notifier_invalidate_range_end(mm, start, end);
2282 list_for_each_entry_safe(page, tmp, &page_list, lru) {
2283 page_remove_rmap(page);
2284 list_del(&page->lru);
2285 put_page(page);
2289 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2290 unsigned long end, struct page *ref_page)
2292 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
2293 __unmap_hugepage_range(vma, start, end, ref_page);
2294 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
2298 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2299 * mappping it owns the reserve page for. The intention is to unmap the page
2300 * from other VMAs and let the children be SIGKILLed if they are faulting the
2301 * same region.
2303 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2304 struct page *page, unsigned long address)
2306 struct hstate *h = hstate_vma(vma);
2307 struct vm_area_struct *iter_vma;
2308 struct address_space *mapping;
2309 struct prio_tree_iter iter;
2310 pgoff_t pgoff;
2313 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2314 * from page cache lookup which is in HPAGE_SIZE units.
2316 address = address & huge_page_mask(h);
2317 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
2318 + (vma->vm_pgoff >> PAGE_SHIFT);
2319 mapping = (struct address_space *)page_private(page);
2322 * Take the mapping lock for the duration of the table walk. As
2323 * this mapping should be shared between all the VMAs,
2324 * __unmap_hugepage_range() is called as the lock is already held
2326 mutex_lock(&mapping->i_mmap_mutex);
2327 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
2328 /* Do not unmap the current VMA */
2329 if (iter_vma == vma)
2330 continue;
2333 * Unmap the page from other VMAs without their own reserves.
2334 * They get marked to be SIGKILLed if they fault in these
2335 * areas. This is because a future no-page fault on this VMA
2336 * could insert a zeroed page instead of the data existing
2337 * from the time of fork. This would look like data corruption
2339 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2340 __unmap_hugepage_range(iter_vma,
2341 address, address + huge_page_size(h),
2342 page);
2344 mutex_unlock(&mapping->i_mmap_mutex);
2346 return 1;
2350 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2352 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2353 unsigned long address, pte_t *ptep, pte_t pte,
2354 struct page *pagecache_page)
2356 struct hstate *h = hstate_vma(vma);
2357 struct page *old_page, *new_page;
2358 int avoidcopy;
2359 int outside_reserve = 0;
2361 old_page = pte_page(pte);
2363 retry_avoidcopy:
2364 /* If no-one else is actually using this page, avoid the copy
2365 * and just make the page writable */
2366 avoidcopy = (page_mapcount(old_page) == 1);
2367 if (avoidcopy) {
2368 if (PageAnon(old_page))
2369 page_move_anon_rmap(old_page, vma, address);
2370 set_huge_ptep_writable(vma, address, ptep);
2371 return 0;
2375 * If the process that created a MAP_PRIVATE mapping is about to
2376 * perform a COW due to a shared page count, attempt to satisfy
2377 * the allocation without using the existing reserves. The pagecache
2378 * page is used to determine if the reserve at this address was
2379 * consumed or not. If reserves were used, a partial faulted mapping
2380 * at the time of fork() could consume its reserves on COW instead
2381 * of the full address range.
2383 if (!(vma->vm_flags & VM_MAYSHARE) &&
2384 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2385 old_page != pagecache_page)
2386 outside_reserve = 1;
2388 page_cache_get(old_page);
2390 /* Drop page_table_lock as buddy allocator may be called */
2391 spin_unlock(&mm->page_table_lock);
2392 new_page = alloc_huge_page(vma, address, outside_reserve);
2394 if (IS_ERR(new_page)) {
2395 page_cache_release(old_page);
2398 * If a process owning a MAP_PRIVATE mapping fails to COW,
2399 * it is due to references held by a child and an insufficient
2400 * huge page pool. To guarantee the original mappers
2401 * reliability, unmap the page from child processes. The child
2402 * may get SIGKILLed if it later faults.
2404 if (outside_reserve) {
2405 BUG_ON(huge_pte_none(pte));
2406 if (unmap_ref_private(mm, vma, old_page, address)) {
2407 BUG_ON(page_count(old_page) != 1);
2408 BUG_ON(huge_pte_none(pte));
2409 spin_lock(&mm->page_table_lock);
2410 goto retry_avoidcopy;
2412 WARN_ON_ONCE(1);
2415 /* Caller expects lock to be held */
2416 spin_lock(&mm->page_table_lock);
2417 return -PTR_ERR(new_page);
2421 * When the original hugepage is shared one, it does not have
2422 * anon_vma prepared.
2424 if (unlikely(anon_vma_prepare(vma))) {
2425 /* Caller expects lock to be held */
2426 spin_lock(&mm->page_table_lock);
2427 return VM_FAULT_OOM;
2430 copy_user_huge_page(new_page, old_page, address, vma,
2431 pages_per_huge_page(h));
2432 __SetPageUptodate(new_page);
2435 * Retake the page_table_lock to check for racing updates
2436 * before the page tables are altered
2438 spin_lock(&mm->page_table_lock);
2439 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2440 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2441 /* Break COW */
2442 mmu_notifier_invalidate_range_start(mm,
2443 address & huge_page_mask(h),
2444 (address & huge_page_mask(h)) + huge_page_size(h));
2445 huge_ptep_clear_flush(vma, address, ptep);
2446 set_huge_pte_at(mm, address, ptep,
2447 make_huge_pte(vma, new_page, 1));
2448 page_remove_rmap(old_page);
2449 hugepage_add_new_anon_rmap(new_page, vma, address);
2450 /* Make the old page be freed below */
2451 new_page = old_page;
2452 mmu_notifier_invalidate_range_end(mm,
2453 address & huge_page_mask(h),
2454 (address & huge_page_mask(h)) + huge_page_size(h));
2456 page_cache_release(new_page);
2457 page_cache_release(old_page);
2458 return 0;
2461 /* Return the pagecache page at a given address within a VMA */
2462 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2463 struct vm_area_struct *vma, unsigned long address)
2465 struct address_space *mapping;
2466 pgoff_t idx;
2468 mapping = vma->vm_file->f_mapping;
2469 idx = vma_hugecache_offset(h, vma, address);
2471 return find_lock_page(mapping, idx);
2475 * Return whether there is a pagecache page to back given address within VMA.
2476 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2478 static bool hugetlbfs_pagecache_present(struct hstate *h,
2479 struct vm_area_struct *vma, unsigned long address)
2481 struct address_space *mapping;
2482 pgoff_t idx;
2483 struct page *page;
2485 mapping = vma->vm_file->f_mapping;
2486 idx = vma_hugecache_offset(h, vma, address);
2488 page = find_get_page(mapping, idx);
2489 if (page)
2490 put_page(page);
2491 return page != NULL;
2494 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2495 unsigned long address, pte_t *ptep, unsigned int flags)
2497 struct hstate *h = hstate_vma(vma);
2498 int ret = VM_FAULT_SIGBUS;
2499 pgoff_t idx;
2500 unsigned long size;
2501 struct page *page;
2502 struct address_space *mapping;
2503 pte_t new_pte;
2506 * Currently, we are forced to kill the process in the event the
2507 * original mapper has unmapped pages from the child due to a failed
2508 * COW. Warn that such a situation has occurred as it may not be obvious
2510 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2511 printk(KERN_WARNING
2512 "PID %d killed due to inadequate hugepage pool\n",
2513 current->pid);
2514 return ret;
2517 mapping = vma->vm_file->f_mapping;
2518 idx = vma_hugecache_offset(h, vma, address);
2521 * Use page lock to guard against racing truncation
2522 * before we get page_table_lock.
2524 retry:
2525 page = find_lock_page(mapping, idx);
2526 if (!page) {
2527 size = i_size_read(mapping->host) >> huge_page_shift(h);
2528 if (idx >= size)
2529 goto out;
2530 page = alloc_huge_page(vma, address, 0);
2531 if (IS_ERR(page)) {
2532 ret = -PTR_ERR(page);
2533 goto out;
2535 clear_huge_page(page, address, pages_per_huge_page(h));
2536 __SetPageUptodate(page);
2538 if (vma->vm_flags & VM_MAYSHARE) {
2539 int err;
2540 struct inode *inode = mapping->host;
2542 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2543 if (err) {
2544 put_page(page);
2545 if (err == -EEXIST)
2546 goto retry;
2547 goto out;
2550 spin_lock(&inode->i_lock);
2551 inode->i_blocks += blocks_per_huge_page(h);
2552 spin_unlock(&inode->i_lock);
2553 page_dup_rmap(page);
2554 } else {
2555 lock_page(page);
2556 if (unlikely(anon_vma_prepare(vma))) {
2557 ret = VM_FAULT_OOM;
2558 goto backout_unlocked;
2560 hugepage_add_new_anon_rmap(page, vma, address);
2562 } else {
2564 * If memory error occurs between mmap() and fault, some process
2565 * don't have hwpoisoned swap entry for errored virtual address.
2566 * So we need to block hugepage fault by PG_hwpoison bit check.
2568 if (unlikely(PageHWPoison(page))) {
2569 ret = VM_FAULT_HWPOISON |
2570 VM_FAULT_SET_HINDEX(h - hstates);
2571 goto backout_unlocked;
2573 page_dup_rmap(page);
2577 * If we are going to COW a private mapping later, we examine the
2578 * pending reservations for this page now. This will ensure that
2579 * any allocations necessary to record that reservation occur outside
2580 * the spinlock.
2582 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2583 if (vma_needs_reservation(h, vma, address) < 0) {
2584 ret = VM_FAULT_OOM;
2585 goto backout_unlocked;
2588 spin_lock(&mm->page_table_lock);
2589 size = i_size_read(mapping->host) >> huge_page_shift(h);
2590 if (idx >= size)
2591 goto backout;
2593 ret = 0;
2594 if (!huge_pte_none(huge_ptep_get(ptep)))
2595 goto backout;
2597 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2598 && (vma->vm_flags & VM_SHARED)));
2599 set_huge_pte_at(mm, address, ptep, new_pte);
2601 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2602 /* Optimization, do the COW without a second fault */
2603 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2606 spin_unlock(&mm->page_table_lock);
2607 unlock_page(page);
2608 out:
2609 return ret;
2611 backout:
2612 spin_unlock(&mm->page_table_lock);
2613 backout_unlocked:
2614 unlock_page(page);
2615 put_page(page);
2616 goto out;
2619 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2620 unsigned long address, unsigned int flags)
2622 pte_t *ptep;
2623 pte_t entry;
2624 int ret;
2625 struct page *page = NULL;
2626 struct page *pagecache_page = NULL;
2627 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2628 struct hstate *h = hstate_vma(vma);
2630 ptep = huge_pte_offset(mm, address);
2631 if (ptep) {
2632 entry = huge_ptep_get(ptep);
2633 if (unlikely(is_hugetlb_entry_migration(entry))) {
2634 migration_entry_wait(mm, (pmd_t *)ptep, address);
2635 return 0;
2636 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2637 return VM_FAULT_HWPOISON_LARGE |
2638 VM_FAULT_SET_HINDEX(h - hstates);
2641 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2642 if (!ptep)
2643 return VM_FAULT_OOM;
2646 * Serialize hugepage allocation and instantiation, so that we don't
2647 * get spurious allocation failures if two CPUs race to instantiate
2648 * the same page in the page cache.
2650 mutex_lock(&hugetlb_instantiation_mutex);
2651 entry = huge_ptep_get(ptep);
2652 if (huge_pte_none(entry)) {
2653 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2654 goto out_mutex;
2657 ret = 0;
2660 * If we are going to COW the mapping later, we examine the pending
2661 * reservations for this page now. This will ensure that any
2662 * allocations necessary to record that reservation occur outside the
2663 * spinlock. For private mappings, we also lookup the pagecache
2664 * page now as it is used to determine if a reservation has been
2665 * consumed.
2667 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2668 if (vma_needs_reservation(h, vma, address) < 0) {
2669 ret = VM_FAULT_OOM;
2670 goto out_mutex;
2673 if (!(vma->vm_flags & VM_MAYSHARE))
2674 pagecache_page = hugetlbfs_pagecache_page(h,
2675 vma, address);
2679 * hugetlb_cow() requires page locks of pte_page(entry) and
2680 * pagecache_page, so here we need take the former one
2681 * when page != pagecache_page or !pagecache_page.
2682 * Note that locking order is always pagecache_page -> page,
2683 * so no worry about deadlock.
2685 page = pte_page(entry);
2686 if (page != pagecache_page)
2687 lock_page(page);
2689 spin_lock(&mm->page_table_lock);
2690 /* Check for a racing update before calling hugetlb_cow */
2691 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2692 goto out_page_table_lock;
2695 if (flags & FAULT_FLAG_WRITE) {
2696 if (!pte_write(entry)) {
2697 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2698 pagecache_page);
2699 goto out_page_table_lock;
2701 entry = pte_mkdirty(entry);
2703 entry = pte_mkyoung(entry);
2704 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2705 flags & FAULT_FLAG_WRITE))
2706 update_mmu_cache(vma, address, ptep);
2708 out_page_table_lock:
2709 spin_unlock(&mm->page_table_lock);
2711 if (pagecache_page) {
2712 unlock_page(pagecache_page);
2713 put_page(pagecache_page);
2715 if (page != pagecache_page)
2716 unlock_page(page);
2718 out_mutex:
2719 mutex_unlock(&hugetlb_instantiation_mutex);
2721 return ret;
2724 /* Can be overriden by architectures */
2725 __attribute__((weak)) struct page *
2726 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2727 pud_t *pud, int write)
2729 BUG();
2730 return NULL;
2733 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2734 struct page **pages, struct vm_area_struct **vmas,
2735 unsigned long *position, int *length, int i,
2736 unsigned int flags)
2738 unsigned long pfn_offset;
2739 unsigned long vaddr = *position;
2740 int remainder = *length;
2741 struct hstate *h = hstate_vma(vma);
2743 spin_lock(&mm->page_table_lock);
2744 while (vaddr < vma->vm_end && remainder) {
2745 pte_t *pte;
2746 int absent;
2747 struct page *page;
2750 * Some archs (sparc64, sh*) have multiple pte_ts to
2751 * each hugepage. We have to make sure we get the
2752 * first, for the page indexing below to work.
2754 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2755 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2758 * When coredumping, it suits get_dump_page if we just return
2759 * an error where there's an empty slot with no huge pagecache
2760 * to back it. This way, we avoid allocating a hugepage, and
2761 * the sparse dumpfile avoids allocating disk blocks, but its
2762 * huge holes still show up with zeroes where they need to be.
2764 if (absent && (flags & FOLL_DUMP) &&
2765 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2766 remainder = 0;
2767 break;
2770 if (absent ||
2771 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2772 int ret;
2774 spin_unlock(&mm->page_table_lock);
2775 ret = hugetlb_fault(mm, vma, vaddr,
2776 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2777 spin_lock(&mm->page_table_lock);
2778 if (!(ret & VM_FAULT_ERROR))
2779 continue;
2781 remainder = 0;
2782 break;
2785 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2786 page = pte_page(huge_ptep_get(pte));
2787 same_page:
2788 if (pages) {
2789 pages[i] = mem_map_offset(page, pfn_offset);
2790 get_page(pages[i]);
2793 if (vmas)
2794 vmas[i] = vma;
2796 vaddr += PAGE_SIZE;
2797 ++pfn_offset;
2798 --remainder;
2799 ++i;
2800 if (vaddr < vma->vm_end && remainder &&
2801 pfn_offset < pages_per_huge_page(h)) {
2803 * We use pfn_offset to avoid touching the pageframes
2804 * of this compound page.
2806 goto same_page;
2809 spin_unlock(&mm->page_table_lock);
2810 *length = remainder;
2811 *position = vaddr;
2813 return i ? i : -EFAULT;
2816 void hugetlb_change_protection(struct vm_area_struct *vma,
2817 unsigned long address, unsigned long end, pgprot_t newprot)
2819 struct mm_struct *mm = vma->vm_mm;
2820 unsigned long start = address;
2821 pte_t *ptep;
2822 pte_t pte;
2823 struct hstate *h = hstate_vma(vma);
2825 BUG_ON(address >= end);
2826 flush_cache_range(vma, address, end);
2828 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
2829 spin_lock(&mm->page_table_lock);
2830 for (; address < end; address += huge_page_size(h)) {
2831 ptep = huge_pte_offset(mm, address);
2832 if (!ptep)
2833 continue;
2834 if (huge_pmd_unshare(mm, &address, ptep))
2835 continue;
2836 if (!huge_pte_none(huge_ptep_get(ptep))) {
2837 pte = huge_ptep_get_and_clear(mm, address, ptep);
2838 pte = pte_mkhuge(pte_modify(pte, newprot));
2839 set_huge_pte_at(mm, address, ptep, pte);
2842 spin_unlock(&mm->page_table_lock);
2843 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
2845 flush_tlb_range(vma, start, end);
2848 int hugetlb_reserve_pages(struct inode *inode,
2849 long from, long to,
2850 struct vm_area_struct *vma,
2851 vm_flags_t vm_flags)
2853 long ret, chg;
2854 struct hstate *h = hstate_inode(inode);
2857 * Only apply hugepage reservation if asked. At fault time, an
2858 * attempt will be made for VM_NORESERVE to allocate a page
2859 * and filesystem quota without using reserves
2861 if (vm_flags & VM_NORESERVE)
2862 return 0;
2865 * Shared mappings base their reservation on the number of pages that
2866 * are already allocated on behalf of the file. Private mappings need
2867 * to reserve the full area even if read-only as mprotect() may be
2868 * called to make the mapping read-write. Assume !vma is a shm mapping
2870 if (!vma || vma->vm_flags & VM_MAYSHARE)
2871 chg = region_chg(&inode->i_mapping->private_list, from, to);
2872 else {
2873 struct resv_map *resv_map = resv_map_alloc();
2874 if (!resv_map)
2875 return -ENOMEM;
2877 chg = to - from;
2879 set_vma_resv_map(vma, resv_map);
2880 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2883 if (chg < 0)
2884 return chg;
2886 /* There must be enough filesystem quota for the mapping */
2887 if (hugetlb_get_quota(inode->i_mapping, chg))
2888 return -ENOSPC;
2891 * Check enough hugepages are available for the reservation.
2892 * Hand back the quota if there are not
2894 ret = hugetlb_acct_memory(h, chg);
2895 if (ret < 0) {
2896 hugetlb_put_quota(inode->i_mapping, chg);
2897 return ret;
2901 * Account for the reservations made. Shared mappings record regions
2902 * that have reservations as they are shared by multiple VMAs.
2903 * When the last VMA disappears, the region map says how much
2904 * the reservation was and the page cache tells how much of
2905 * the reservation was consumed. Private mappings are per-VMA and
2906 * only the consumed reservations are tracked. When the VMA
2907 * disappears, the original reservation is the VMA size and the
2908 * consumed reservations are stored in the map. Hence, nothing
2909 * else has to be done for private mappings here
2911 if (!vma || vma->vm_flags & VM_MAYSHARE)
2912 region_add(&inode->i_mapping->private_list, from, to);
2913 return 0;
2916 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2918 struct hstate *h = hstate_inode(inode);
2919 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2921 spin_lock(&inode->i_lock);
2922 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2923 spin_unlock(&inode->i_lock);
2925 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2926 hugetlb_acct_memory(h, -(chg - freed));
2929 #ifdef CONFIG_MEMORY_FAILURE
2931 /* Should be called in hugetlb_lock */
2932 static int is_hugepage_on_freelist(struct page *hpage)
2934 struct page *page;
2935 struct page *tmp;
2936 struct hstate *h = page_hstate(hpage);
2937 int nid = page_to_nid(hpage);
2939 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
2940 if (page == hpage)
2941 return 1;
2942 return 0;
2946 * This function is called from memory failure code.
2947 * Assume the caller holds page lock of the head page.
2949 int dequeue_hwpoisoned_huge_page(struct page *hpage)
2951 struct hstate *h = page_hstate(hpage);
2952 int nid = page_to_nid(hpage);
2953 int ret = -EBUSY;
2955 spin_lock(&hugetlb_lock);
2956 if (is_hugepage_on_freelist(hpage)) {
2957 list_del(&hpage->lru);
2958 set_page_refcounted(hpage);
2959 h->free_huge_pages--;
2960 h->free_huge_pages_node[nid]--;
2961 ret = 0;
2963 spin_unlock(&hugetlb_lock);
2964 return ret;
2966 #endif