slub: rename calculate_min_partial() to set_min_partial()
[linux-2.6/mini2440.git] / mm / hugetlb.c
blob107da3d809a87b0ad13e57256a050763a0b3d17b
1 /*
2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
4 */
5 #include <linux/gfp.h>
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/mm.h>
10 #include <linux/seq_file.h>
11 #include <linux/sysctl.h>
12 #include <linux/highmem.h>
13 #include <linux/mmu_notifier.h>
14 #include <linux/nodemask.h>
15 #include <linux/pagemap.h>
16 #include <linux/mempolicy.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
22 #include <asm/page.h>
23 #include <asm/pgtable.h>
24 #include <asm/io.h>
26 #include <linux/hugetlb.h>
27 #include "internal.h"
29 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
30 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
31 unsigned long hugepages_treat_as_movable;
33 static int max_hstate;
34 unsigned int default_hstate_idx;
35 struct hstate hstates[HUGE_MAX_HSTATE];
37 __initdata LIST_HEAD(huge_boot_pages);
39 /* for command line parsing */
40 static struct hstate * __initdata parsed_hstate;
41 static unsigned long __initdata default_hstate_max_huge_pages;
42 static unsigned long __initdata default_hstate_size;
44 #define for_each_hstate(h) \
45 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
48 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
50 static DEFINE_SPINLOCK(hugetlb_lock);
53 * Region tracking -- allows tracking of reservations and instantiated pages
54 * across the pages in a mapping.
56 * The region data structures are protected by a combination of the mmap_sem
57 * and the hugetlb_instantion_mutex. To access or modify a region the caller
58 * must either hold the mmap_sem for write, or the mmap_sem for read and
59 * the hugetlb_instantiation mutex:
61 * down_write(&mm->mmap_sem);
62 * or
63 * down_read(&mm->mmap_sem);
64 * mutex_lock(&hugetlb_instantiation_mutex);
66 struct file_region {
67 struct list_head link;
68 long from;
69 long to;
72 static long region_add(struct list_head *head, long f, long t)
74 struct file_region *rg, *nrg, *trg;
76 /* Locate the region we are either in or before. */
77 list_for_each_entry(rg, head, link)
78 if (f <= rg->to)
79 break;
81 /* Round our left edge to the current segment if it encloses us. */
82 if (f > rg->from)
83 f = rg->from;
85 /* Check for and consume any regions we now overlap with. */
86 nrg = rg;
87 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
88 if (&rg->link == head)
89 break;
90 if (rg->from > t)
91 break;
93 /* If this area reaches higher then extend our area to
94 * include it completely. If this is not the first area
95 * which we intend to reuse, free it. */
96 if (rg->to > t)
97 t = rg->to;
98 if (rg != nrg) {
99 list_del(&rg->link);
100 kfree(rg);
103 nrg->from = f;
104 nrg->to = t;
105 return 0;
108 static long region_chg(struct list_head *head, long f, long t)
110 struct file_region *rg, *nrg;
111 long chg = 0;
113 /* Locate the region we are before or in. */
114 list_for_each_entry(rg, head, link)
115 if (f <= rg->to)
116 break;
118 /* If we are below the current region then a new region is required.
119 * Subtle, allocate a new region at the position but make it zero
120 * size such that we can guarantee to record the reservation. */
121 if (&rg->link == head || t < rg->from) {
122 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
123 if (!nrg)
124 return -ENOMEM;
125 nrg->from = f;
126 nrg->to = f;
127 INIT_LIST_HEAD(&nrg->link);
128 list_add(&nrg->link, rg->link.prev);
130 return t - f;
133 /* Round our left edge to the current segment if it encloses us. */
134 if (f > rg->from)
135 f = rg->from;
136 chg = t - f;
138 /* Check for and consume any regions we now overlap with. */
139 list_for_each_entry(rg, rg->link.prev, link) {
140 if (&rg->link == head)
141 break;
142 if (rg->from > t)
143 return chg;
145 /* We overlap with this area, if it extends futher than
146 * us then we must extend ourselves. Account for its
147 * existing reservation. */
148 if (rg->to > t) {
149 chg += rg->to - t;
150 t = rg->to;
152 chg -= rg->to - rg->from;
154 return chg;
157 static long region_truncate(struct list_head *head, long end)
159 struct file_region *rg, *trg;
160 long chg = 0;
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg, head, link)
164 if (end <= rg->to)
165 break;
166 if (&rg->link == head)
167 return 0;
169 /* If we are in the middle of a region then adjust it. */
170 if (end > rg->from) {
171 chg = rg->to - end;
172 rg->to = end;
173 rg = list_entry(rg->link.next, typeof(*rg), link);
176 /* Drop any remaining regions. */
177 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
178 if (&rg->link == head)
179 break;
180 chg += rg->to - rg->from;
181 list_del(&rg->link);
182 kfree(rg);
184 return chg;
187 static long region_count(struct list_head *head, long f, long t)
189 struct file_region *rg;
190 long chg = 0;
192 /* Locate each segment we overlap with, and count that overlap. */
193 list_for_each_entry(rg, head, link) {
194 int seg_from;
195 int seg_to;
197 if (rg->to <= f)
198 continue;
199 if (rg->from >= t)
200 break;
202 seg_from = max(rg->from, f);
203 seg_to = min(rg->to, t);
205 chg += seg_to - seg_from;
208 return chg;
212 * Convert the address within this vma to the page offset within
213 * the mapping, in pagecache page units; huge pages here.
215 static pgoff_t vma_hugecache_offset(struct hstate *h,
216 struct vm_area_struct *vma, unsigned long address)
218 return ((address - vma->vm_start) >> huge_page_shift(h)) +
219 (vma->vm_pgoff >> huge_page_order(h));
223 * Return the size of the pages allocated when backing a VMA. In the majority
224 * cases this will be same size as used by the page table entries.
226 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
228 struct hstate *hstate;
230 if (!is_vm_hugetlb_page(vma))
231 return PAGE_SIZE;
233 hstate = hstate_vma(vma);
235 return 1UL << (hstate->order + PAGE_SHIFT);
239 * Return the page size being used by the MMU to back a VMA. In the majority
240 * of cases, the page size used by the kernel matches the MMU size. On
241 * architectures where it differs, an architecture-specific version of this
242 * function is required.
244 #ifndef vma_mmu_pagesize
245 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
247 return vma_kernel_pagesize(vma);
249 #endif
252 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
253 * bits of the reservation map pointer, which are always clear due to
254 * alignment.
256 #define HPAGE_RESV_OWNER (1UL << 0)
257 #define HPAGE_RESV_UNMAPPED (1UL << 1)
258 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
261 * These helpers are used to track how many pages are reserved for
262 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
263 * is guaranteed to have their future faults succeed.
265 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
266 * the reserve counters are updated with the hugetlb_lock held. It is safe
267 * to reset the VMA at fork() time as it is not in use yet and there is no
268 * chance of the global counters getting corrupted as a result of the values.
270 * The private mapping reservation is represented in a subtly different
271 * manner to a shared mapping. A shared mapping has a region map associated
272 * with the underlying file, this region map represents the backing file
273 * pages which have ever had a reservation assigned which this persists even
274 * after the page is instantiated. A private mapping has a region map
275 * associated with the original mmap which is attached to all VMAs which
276 * reference it, this region map represents those offsets which have consumed
277 * reservation ie. where pages have been instantiated.
279 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
281 return (unsigned long)vma->vm_private_data;
284 static void set_vma_private_data(struct vm_area_struct *vma,
285 unsigned long value)
287 vma->vm_private_data = (void *)value;
290 struct resv_map {
291 struct kref refs;
292 struct list_head regions;
295 static struct resv_map *resv_map_alloc(void)
297 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
298 if (!resv_map)
299 return NULL;
301 kref_init(&resv_map->refs);
302 INIT_LIST_HEAD(&resv_map->regions);
304 return resv_map;
307 static void resv_map_release(struct kref *ref)
309 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
311 /* Clear out any active regions before we release the map. */
312 region_truncate(&resv_map->regions, 0);
313 kfree(resv_map);
316 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
318 VM_BUG_ON(!is_vm_hugetlb_page(vma));
319 if (!(vma->vm_flags & VM_SHARED))
320 return (struct resv_map *)(get_vma_private_data(vma) &
321 ~HPAGE_RESV_MASK);
322 return NULL;
325 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
327 VM_BUG_ON(!is_vm_hugetlb_page(vma));
328 VM_BUG_ON(vma->vm_flags & VM_SHARED);
330 set_vma_private_data(vma, (get_vma_private_data(vma) &
331 HPAGE_RESV_MASK) | (unsigned long)map);
334 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
336 VM_BUG_ON(!is_vm_hugetlb_page(vma));
337 VM_BUG_ON(vma->vm_flags & VM_SHARED);
339 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
342 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
344 VM_BUG_ON(!is_vm_hugetlb_page(vma));
346 return (get_vma_private_data(vma) & flag) != 0;
349 /* Decrement the reserved pages in the hugepage pool by one */
350 static void decrement_hugepage_resv_vma(struct hstate *h,
351 struct vm_area_struct *vma)
353 if (vma->vm_flags & VM_NORESERVE)
354 return;
356 if (vma->vm_flags & VM_SHARED) {
357 /* Shared mappings always use reserves */
358 h->resv_huge_pages--;
359 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
361 * Only the process that called mmap() has reserves for
362 * private mappings.
364 h->resv_huge_pages--;
368 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
369 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
371 VM_BUG_ON(!is_vm_hugetlb_page(vma));
372 if (!(vma->vm_flags & VM_SHARED))
373 vma->vm_private_data = (void *)0;
376 /* Returns true if the VMA has associated reserve pages */
377 static int vma_has_reserves(struct vm_area_struct *vma)
379 if (vma->vm_flags & VM_SHARED)
380 return 1;
381 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
382 return 1;
383 return 0;
386 static void clear_gigantic_page(struct page *page,
387 unsigned long addr, unsigned long sz)
389 int i;
390 struct page *p = page;
392 might_sleep();
393 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
394 cond_resched();
395 clear_user_highpage(p, addr + i * PAGE_SIZE);
398 static void clear_huge_page(struct page *page,
399 unsigned long addr, unsigned long sz)
401 int i;
403 if (unlikely(sz > MAX_ORDER_NR_PAGES)) {
404 clear_gigantic_page(page, addr, sz);
405 return;
408 might_sleep();
409 for (i = 0; i < sz/PAGE_SIZE; i++) {
410 cond_resched();
411 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
415 static void copy_gigantic_page(struct page *dst, struct page *src,
416 unsigned long addr, struct vm_area_struct *vma)
418 int i;
419 struct hstate *h = hstate_vma(vma);
420 struct page *dst_base = dst;
421 struct page *src_base = src;
422 might_sleep();
423 for (i = 0; i < pages_per_huge_page(h); ) {
424 cond_resched();
425 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
427 i++;
428 dst = mem_map_next(dst, dst_base, i);
429 src = mem_map_next(src, src_base, i);
432 static void copy_huge_page(struct page *dst, struct page *src,
433 unsigned long addr, struct vm_area_struct *vma)
435 int i;
436 struct hstate *h = hstate_vma(vma);
438 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
439 copy_gigantic_page(dst, src, addr, vma);
440 return;
443 might_sleep();
444 for (i = 0; i < pages_per_huge_page(h); i++) {
445 cond_resched();
446 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
450 static void enqueue_huge_page(struct hstate *h, struct page *page)
452 int nid = page_to_nid(page);
453 list_add(&page->lru, &h->hugepage_freelists[nid]);
454 h->free_huge_pages++;
455 h->free_huge_pages_node[nid]++;
458 static struct page *dequeue_huge_page(struct hstate *h)
460 int nid;
461 struct page *page = NULL;
463 for (nid = 0; nid < MAX_NUMNODES; ++nid) {
464 if (!list_empty(&h->hugepage_freelists[nid])) {
465 page = list_entry(h->hugepage_freelists[nid].next,
466 struct page, lru);
467 list_del(&page->lru);
468 h->free_huge_pages--;
469 h->free_huge_pages_node[nid]--;
470 break;
473 return page;
476 static struct page *dequeue_huge_page_vma(struct hstate *h,
477 struct vm_area_struct *vma,
478 unsigned long address, int avoid_reserve)
480 int nid;
481 struct page *page = NULL;
482 struct mempolicy *mpol;
483 nodemask_t *nodemask;
484 struct zonelist *zonelist = huge_zonelist(vma, address,
485 htlb_alloc_mask, &mpol, &nodemask);
486 struct zone *zone;
487 struct zoneref *z;
490 * A child process with MAP_PRIVATE mappings created by their parent
491 * have no page reserves. This check ensures that reservations are
492 * not "stolen". The child may still get SIGKILLed
494 if (!vma_has_reserves(vma) &&
495 h->free_huge_pages - h->resv_huge_pages == 0)
496 return NULL;
498 /* If reserves cannot be used, ensure enough pages are in the pool */
499 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
500 return NULL;
502 for_each_zone_zonelist_nodemask(zone, z, zonelist,
503 MAX_NR_ZONES - 1, nodemask) {
504 nid = zone_to_nid(zone);
505 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
506 !list_empty(&h->hugepage_freelists[nid])) {
507 page = list_entry(h->hugepage_freelists[nid].next,
508 struct page, lru);
509 list_del(&page->lru);
510 h->free_huge_pages--;
511 h->free_huge_pages_node[nid]--;
513 if (!avoid_reserve)
514 decrement_hugepage_resv_vma(h, vma);
516 break;
519 mpol_cond_put(mpol);
520 return page;
523 static void update_and_free_page(struct hstate *h, struct page *page)
525 int i;
527 VM_BUG_ON(h->order >= MAX_ORDER);
529 h->nr_huge_pages--;
530 h->nr_huge_pages_node[page_to_nid(page)]--;
531 for (i = 0; i < pages_per_huge_page(h); i++) {
532 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
533 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
534 1 << PG_private | 1<< PG_writeback);
536 set_compound_page_dtor(page, NULL);
537 set_page_refcounted(page);
538 arch_release_hugepage(page);
539 __free_pages(page, huge_page_order(h));
542 struct hstate *size_to_hstate(unsigned long size)
544 struct hstate *h;
546 for_each_hstate(h) {
547 if (huge_page_size(h) == size)
548 return h;
550 return NULL;
553 static void free_huge_page(struct page *page)
556 * Can't pass hstate in here because it is called from the
557 * compound page destructor.
559 struct hstate *h = page_hstate(page);
560 int nid = page_to_nid(page);
561 struct address_space *mapping;
563 mapping = (struct address_space *) page_private(page);
564 set_page_private(page, 0);
565 BUG_ON(page_count(page));
566 INIT_LIST_HEAD(&page->lru);
568 spin_lock(&hugetlb_lock);
569 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
570 update_and_free_page(h, page);
571 h->surplus_huge_pages--;
572 h->surplus_huge_pages_node[nid]--;
573 } else {
574 enqueue_huge_page(h, page);
576 spin_unlock(&hugetlb_lock);
577 if (mapping)
578 hugetlb_put_quota(mapping, 1);
582 * Increment or decrement surplus_huge_pages. Keep node-specific counters
583 * balanced by operating on them in a round-robin fashion.
584 * Returns 1 if an adjustment was made.
586 static int adjust_pool_surplus(struct hstate *h, int delta)
588 static int prev_nid;
589 int nid = prev_nid;
590 int ret = 0;
592 VM_BUG_ON(delta != -1 && delta != 1);
593 do {
594 nid = next_node(nid, node_online_map);
595 if (nid == MAX_NUMNODES)
596 nid = first_node(node_online_map);
598 /* To shrink on this node, there must be a surplus page */
599 if (delta < 0 && !h->surplus_huge_pages_node[nid])
600 continue;
601 /* Surplus cannot exceed the total number of pages */
602 if (delta > 0 && h->surplus_huge_pages_node[nid] >=
603 h->nr_huge_pages_node[nid])
604 continue;
606 h->surplus_huge_pages += delta;
607 h->surplus_huge_pages_node[nid] += delta;
608 ret = 1;
609 break;
610 } while (nid != prev_nid);
612 prev_nid = nid;
613 return ret;
616 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
618 set_compound_page_dtor(page, free_huge_page);
619 spin_lock(&hugetlb_lock);
620 h->nr_huge_pages++;
621 h->nr_huge_pages_node[nid]++;
622 spin_unlock(&hugetlb_lock);
623 put_page(page); /* free it into the hugepage allocator */
626 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
628 struct page *page;
630 if (h->order >= MAX_ORDER)
631 return NULL;
633 page = alloc_pages_node(nid,
634 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
635 __GFP_REPEAT|__GFP_NOWARN,
636 huge_page_order(h));
637 if (page) {
638 if (arch_prepare_hugepage(page)) {
639 __free_pages(page, huge_page_order(h));
640 return NULL;
642 prep_new_huge_page(h, page, nid);
645 return page;
649 * Use a helper variable to find the next node and then
650 * copy it back to hugetlb_next_nid afterwards:
651 * otherwise there's a window in which a racer might
652 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
653 * But we don't need to use a spin_lock here: it really
654 * doesn't matter if occasionally a racer chooses the
655 * same nid as we do. Move nid forward in the mask even
656 * if we just successfully allocated a hugepage so that
657 * the next caller gets hugepages on the next node.
659 static int hstate_next_node(struct hstate *h)
661 int next_nid;
662 next_nid = next_node(h->hugetlb_next_nid, node_online_map);
663 if (next_nid == MAX_NUMNODES)
664 next_nid = first_node(node_online_map);
665 h->hugetlb_next_nid = next_nid;
666 return next_nid;
669 static int alloc_fresh_huge_page(struct hstate *h)
671 struct page *page;
672 int start_nid;
673 int next_nid;
674 int ret = 0;
676 start_nid = h->hugetlb_next_nid;
678 do {
679 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid);
680 if (page)
681 ret = 1;
682 next_nid = hstate_next_node(h);
683 } while (!page && h->hugetlb_next_nid != start_nid);
685 if (ret)
686 count_vm_event(HTLB_BUDDY_PGALLOC);
687 else
688 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
690 return ret;
693 static struct page *alloc_buddy_huge_page(struct hstate *h,
694 struct vm_area_struct *vma, unsigned long address)
696 struct page *page;
697 unsigned int nid;
699 if (h->order >= MAX_ORDER)
700 return NULL;
703 * Assume we will successfully allocate the surplus page to
704 * prevent racing processes from causing the surplus to exceed
705 * overcommit
707 * This however introduces a different race, where a process B
708 * tries to grow the static hugepage pool while alloc_pages() is
709 * called by process A. B will only examine the per-node
710 * counters in determining if surplus huge pages can be
711 * converted to normal huge pages in adjust_pool_surplus(). A
712 * won't be able to increment the per-node counter, until the
713 * lock is dropped by B, but B doesn't drop hugetlb_lock until
714 * no more huge pages can be converted from surplus to normal
715 * state (and doesn't try to convert again). Thus, we have a
716 * case where a surplus huge page exists, the pool is grown, and
717 * the surplus huge page still exists after, even though it
718 * should just have been converted to a normal huge page. This
719 * does not leak memory, though, as the hugepage will be freed
720 * once it is out of use. It also does not allow the counters to
721 * go out of whack in adjust_pool_surplus() as we don't modify
722 * the node values until we've gotten the hugepage and only the
723 * per-node value is checked there.
725 spin_lock(&hugetlb_lock);
726 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
727 spin_unlock(&hugetlb_lock);
728 return NULL;
729 } else {
730 h->nr_huge_pages++;
731 h->surplus_huge_pages++;
733 spin_unlock(&hugetlb_lock);
735 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
736 __GFP_REPEAT|__GFP_NOWARN,
737 huge_page_order(h));
739 if (page && arch_prepare_hugepage(page)) {
740 __free_pages(page, huge_page_order(h));
741 return NULL;
744 spin_lock(&hugetlb_lock);
745 if (page) {
747 * This page is now managed by the hugetlb allocator and has
748 * no users -- drop the buddy allocator's reference.
750 put_page_testzero(page);
751 VM_BUG_ON(page_count(page));
752 nid = page_to_nid(page);
753 set_compound_page_dtor(page, free_huge_page);
755 * We incremented the global counters already
757 h->nr_huge_pages_node[nid]++;
758 h->surplus_huge_pages_node[nid]++;
759 __count_vm_event(HTLB_BUDDY_PGALLOC);
760 } else {
761 h->nr_huge_pages--;
762 h->surplus_huge_pages--;
763 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
765 spin_unlock(&hugetlb_lock);
767 return page;
771 * Increase the hugetlb pool such that it can accomodate a reservation
772 * of size 'delta'.
774 static int gather_surplus_pages(struct hstate *h, int delta)
776 struct list_head surplus_list;
777 struct page *page, *tmp;
778 int ret, i;
779 int needed, allocated;
781 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
782 if (needed <= 0) {
783 h->resv_huge_pages += delta;
784 return 0;
787 allocated = 0;
788 INIT_LIST_HEAD(&surplus_list);
790 ret = -ENOMEM;
791 retry:
792 spin_unlock(&hugetlb_lock);
793 for (i = 0; i < needed; i++) {
794 page = alloc_buddy_huge_page(h, NULL, 0);
795 if (!page) {
797 * We were not able to allocate enough pages to
798 * satisfy the entire reservation so we free what
799 * we've allocated so far.
801 spin_lock(&hugetlb_lock);
802 needed = 0;
803 goto free;
806 list_add(&page->lru, &surplus_list);
808 allocated += needed;
811 * After retaking hugetlb_lock, we need to recalculate 'needed'
812 * because either resv_huge_pages or free_huge_pages may have changed.
814 spin_lock(&hugetlb_lock);
815 needed = (h->resv_huge_pages + delta) -
816 (h->free_huge_pages + allocated);
817 if (needed > 0)
818 goto retry;
821 * The surplus_list now contains _at_least_ the number of extra pages
822 * needed to accomodate the reservation. Add the appropriate number
823 * of pages to the hugetlb pool and free the extras back to the buddy
824 * allocator. Commit the entire reservation here to prevent another
825 * process from stealing the pages as they are added to the pool but
826 * before they are reserved.
828 needed += allocated;
829 h->resv_huge_pages += delta;
830 ret = 0;
831 free:
832 /* Free the needed pages to the hugetlb pool */
833 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
834 if ((--needed) < 0)
835 break;
836 list_del(&page->lru);
837 enqueue_huge_page(h, page);
840 /* Free unnecessary surplus pages to the buddy allocator */
841 if (!list_empty(&surplus_list)) {
842 spin_unlock(&hugetlb_lock);
843 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
844 list_del(&page->lru);
846 * The page has a reference count of zero already, so
847 * call free_huge_page directly instead of using
848 * put_page. This must be done with hugetlb_lock
849 * unlocked which is safe because free_huge_page takes
850 * hugetlb_lock before deciding how to free the page.
852 free_huge_page(page);
854 spin_lock(&hugetlb_lock);
857 return ret;
861 * When releasing a hugetlb pool reservation, any surplus pages that were
862 * allocated to satisfy the reservation must be explicitly freed if they were
863 * never used.
865 static void return_unused_surplus_pages(struct hstate *h,
866 unsigned long unused_resv_pages)
868 static int nid = -1;
869 struct page *page;
870 unsigned long nr_pages;
873 * We want to release as many surplus pages as possible, spread
874 * evenly across all nodes. Iterate across all nodes until we
875 * can no longer free unreserved surplus pages. This occurs when
876 * the nodes with surplus pages have no free pages.
878 unsigned long remaining_iterations = num_online_nodes();
880 /* Uncommit the reservation */
881 h->resv_huge_pages -= unused_resv_pages;
883 /* Cannot return gigantic pages currently */
884 if (h->order >= MAX_ORDER)
885 return;
887 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
889 while (remaining_iterations-- && nr_pages) {
890 nid = next_node(nid, node_online_map);
891 if (nid == MAX_NUMNODES)
892 nid = first_node(node_online_map);
894 if (!h->surplus_huge_pages_node[nid])
895 continue;
897 if (!list_empty(&h->hugepage_freelists[nid])) {
898 page = list_entry(h->hugepage_freelists[nid].next,
899 struct page, lru);
900 list_del(&page->lru);
901 update_and_free_page(h, page);
902 h->free_huge_pages--;
903 h->free_huge_pages_node[nid]--;
904 h->surplus_huge_pages--;
905 h->surplus_huge_pages_node[nid]--;
906 nr_pages--;
907 remaining_iterations = num_online_nodes();
913 * Determine if the huge page at addr within the vma has an associated
914 * reservation. Where it does not we will need to logically increase
915 * reservation and actually increase quota before an allocation can occur.
916 * Where any new reservation would be required the reservation change is
917 * prepared, but not committed. Once the page has been quota'd allocated
918 * an instantiated the change should be committed via vma_commit_reservation.
919 * No action is required on failure.
921 static int vma_needs_reservation(struct hstate *h,
922 struct vm_area_struct *vma, unsigned long addr)
924 struct address_space *mapping = vma->vm_file->f_mapping;
925 struct inode *inode = mapping->host;
927 if (vma->vm_flags & VM_SHARED) {
928 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
929 return region_chg(&inode->i_mapping->private_list,
930 idx, idx + 1);
932 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
933 return 1;
935 } else {
936 int err;
937 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
938 struct resv_map *reservations = vma_resv_map(vma);
940 err = region_chg(&reservations->regions, idx, idx + 1);
941 if (err < 0)
942 return err;
943 return 0;
946 static void vma_commit_reservation(struct hstate *h,
947 struct vm_area_struct *vma, unsigned long addr)
949 struct address_space *mapping = vma->vm_file->f_mapping;
950 struct inode *inode = mapping->host;
952 if (vma->vm_flags & VM_SHARED) {
953 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
954 region_add(&inode->i_mapping->private_list, idx, idx + 1);
956 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
957 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
958 struct resv_map *reservations = vma_resv_map(vma);
960 /* Mark this page used in the map. */
961 region_add(&reservations->regions, idx, idx + 1);
965 static struct page *alloc_huge_page(struct vm_area_struct *vma,
966 unsigned long addr, int avoid_reserve)
968 struct hstate *h = hstate_vma(vma);
969 struct page *page;
970 struct address_space *mapping = vma->vm_file->f_mapping;
971 struct inode *inode = mapping->host;
972 unsigned int chg;
975 * Processes that did not create the mapping will have no reserves and
976 * will not have accounted against quota. Check that the quota can be
977 * made before satisfying the allocation
978 * MAP_NORESERVE mappings may also need pages and quota allocated
979 * if no reserve mapping overlaps.
981 chg = vma_needs_reservation(h, vma, addr);
982 if (chg < 0)
983 return ERR_PTR(chg);
984 if (chg)
985 if (hugetlb_get_quota(inode->i_mapping, chg))
986 return ERR_PTR(-ENOSPC);
988 spin_lock(&hugetlb_lock);
989 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
990 spin_unlock(&hugetlb_lock);
992 if (!page) {
993 page = alloc_buddy_huge_page(h, vma, addr);
994 if (!page) {
995 hugetlb_put_quota(inode->i_mapping, chg);
996 return ERR_PTR(-VM_FAULT_OOM);
1000 set_page_refcounted(page);
1001 set_page_private(page, (unsigned long) mapping);
1003 vma_commit_reservation(h, vma, addr);
1005 return page;
1008 int __weak alloc_bootmem_huge_page(struct hstate *h)
1010 struct huge_bootmem_page *m;
1011 int nr_nodes = nodes_weight(node_online_map);
1013 while (nr_nodes) {
1014 void *addr;
1016 addr = __alloc_bootmem_node_nopanic(
1017 NODE_DATA(h->hugetlb_next_nid),
1018 huge_page_size(h), huge_page_size(h), 0);
1020 if (addr) {
1022 * Use the beginning of the huge page to store the
1023 * huge_bootmem_page struct (until gather_bootmem
1024 * puts them into the mem_map).
1026 m = addr;
1027 goto found;
1029 hstate_next_node(h);
1030 nr_nodes--;
1032 return 0;
1034 found:
1035 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1036 /* Put them into a private list first because mem_map is not up yet */
1037 list_add(&m->list, &huge_boot_pages);
1038 m->hstate = h;
1039 return 1;
1042 static void prep_compound_huge_page(struct page *page, int order)
1044 if (unlikely(order > (MAX_ORDER - 1)))
1045 prep_compound_gigantic_page(page, order);
1046 else
1047 prep_compound_page(page, order);
1050 /* Put bootmem huge pages into the standard lists after mem_map is up */
1051 static void __init gather_bootmem_prealloc(void)
1053 struct huge_bootmem_page *m;
1055 list_for_each_entry(m, &huge_boot_pages, list) {
1056 struct page *page = virt_to_page(m);
1057 struct hstate *h = m->hstate;
1058 __ClearPageReserved(page);
1059 WARN_ON(page_count(page) != 1);
1060 prep_compound_huge_page(page, h->order);
1061 prep_new_huge_page(h, page, page_to_nid(page));
1065 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1067 unsigned long i;
1069 for (i = 0; i < h->max_huge_pages; ++i) {
1070 if (h->order >= MAX_ORDER) {
1071 if (!alloc_bootmem_huge_page(h))
1072 break;
1073 } else if (!alloc_fresh_huge_page(h))
1074 break;
1076 h->max_huge_pages = i;
1079 static void __init hugetlb_init_hstates(void)
1081 struct hstate *h;
1083 for_each_hstate(h) {
1084 /* oversize hugepages were init'ed in early boot */
1085 if (h->order < MAX_ORDER)
1086 hugetlb_hstate_alloc_pages(h);
1090 static char * __init memfmt(char *buf, unsigned long n)
1092 if (n >= (1UL << 30))
1093 sprintf(buf, "%lu GB", n >> 30);
1094 else if (n >= (1UL << 20))
1095 sprintf(buf, "%lu MB", n >> 20);
1096 else
1097 sprintf(buf, "%lu KB", n >> 10);
1098 return buf;
1101 static void __init report_hugepages(void)
1103 struct hstate *h;
1105 for_each_hstate(h) {
1106 char buf[32];
1107 printk(KERN_INFO "HugeTLB registered %s page size, "
1108 "pre-allocated %ld pages\n",
1109 memfmt(buf, huge_page_size(h)),
1110 h->free_huge_pages);
1114 #ifdef CONFIG_HIGHMEM
1115 static void try_to_free_low(struct hstate *h, unsigned long count)
1117 int i;
1119 if (h->order >= MAX_ORDER)
1120 return;
1122 for (i = 0; i < MAX_NUMNODES; ++i) {
1123 struct page *page, *next;
1124 struct list_head *freel = &h->hugepage_freelists[i];
1125 list_for_each_entry_safe(page, next, freel, lru) {
1126 if (count >= h->nr_huge_pages)
1127 return;
1128 if (PageHighMem(page))
1129 continue;
1130 list_del(&page->lru);
1131 update_and_free_page(h, page);
1132 h->free_huge_pages--;
1133 h->free_huge_pages_node[page_to_nid(page)]--;
1137 #else
1138 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1141 #endif
1143 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1144 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1146 unsigned long min_count, ret;
1148 if (h->order >= MAX_ORDER)
1149 return h->max_huge_pages;
1152 * Increase the pool size
1153 * First take pages out of surplus state. Then make up the
1154 * remaining difference by allocating fresh huge pages.
1156 * We might race with alloc_buddy_huge_page() here and be unable
1157 * to convert a surplus huge page to a normal huge page. That is
1158 * not critical, though, it just means the overall size of the
1159 * pool might be one hugepage larger than it needs to be, but
1160 * within all the constraints specified by the sysctls.
1162 spin_lock(&hugetlb_lock);
1163 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1164 if (!adjust_pool_surplus(h, -1))
1165 break;
1168 while (count > persistent_huge_pages(h)) {
1170 * If this allocation races such that we no longer need the
1171 * page, free_huge_page will handle it by freeing the page
1172 * and reducing the surplus.
1174 spin_unlock(&hugetlb_lock);
1175 ret = alloc_fresh_huge_page(h);
1176 spin_lock(&hugetlb_lock);
1177 if (!ret)
1178 goto out;
1183 * Decrease the pool size
1184 * First return free pages to the buddy allocator (being careful
1185 * to keep enough around to satisfy reservations). Then place
1186 * pages into surplus state as needed so the pool will shrink
1187 * to the desired size as pages become free.
1189 * By placing pages into the surplus state independent of the
1190 * overcommit value, we are allowing the surplus pool size to
1191 * exceed overcommit. There are few sane options here. Since
1192 * alloc_buddy_huge_page() is checking the global counter,
1193 * though, we'll note that we're not allowed to exceed surplus
1194 * and won't grow the pool anywhere else. Not until one of the
1195 * sysctls are changed, or the surplus pages go out of use.
1197 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1198 min_count = max(count, min_count);
1199 try_to_free_low(h, min_count);
1200 while (min_count < persistent_huge_pages(h)) {
1201 struct page *page = dequeue_huge_page(h);
1202 if (!page)
1203 break;
1204 update_and_free_page(h, page);
1206 while (count < persistent_huge_pages(h)) {
1207 if (!adjust_pool_surplus(h, 1))
1208 break;
1210 out:
1211 ret = persistent_huge_pages(h);
1212 spin_unlock(&hugetlb_lock);
1213 return ret;
1216 #define HSTATE_ATTR_RO(_name) \
1217 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1219 #define HSTATE_ATTR(_name) \
1220 static struct kobj_attribute _name##_attr = \
1221 __ATTR(_name, 0644, _name##_show, _name##_store)
1223 static struct kobject *hugepages_kobj;
1224 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1226 static struct hstate *kobj_to_hstate(struct kobject *kobj)
1228 int i;
1229 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1230 if (hstate_kobjs[i] == kobj)
1231 return &hstates[i];
1232 BUG();
1233 return NULL;
1236 static ssize_t nr_hugepages_show(struct kobject *kobj,
1237 struct kobj_attribute *attr, char *buf)
1239 struct hstate *h = kobj_to_hstate(kobj);
1240 return sprintf(buf, "%lu\n", h->nr_huge_pages);
1242 static ssize_t nr_hugepages_store(struct kobject *kobj,
1243 struct kobj_attribute *attr, const char *buf, size_t count)
1245 int err;
1246 unsigned long input;
1247 struct hstate *h = kobj_to_hstate(kobj);
1249 err = strict_strtoul(buf, 10, &input);
1250 if (err)
1251 return 0;
1253 h->max_huge_pages = set_max_huge_pages(h, input);
1255 return count;
1257 HSTATE_ATTR(nr_hugepages);
1259 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1260 struct kobj_attribute *attr, char *buf)
1262 struct hstate *h = kobj_to_hstate(kobj);
1263 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1265 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1266 struct kobj_attribute *attr, const char *buf, size_t count)
1268 int err;
1269 unsigned long input;
1270 struct hstate *h = kobj_to_hstate(kobj);
1272 err = strict_strtoul(buf, 10, &input);
1273 if (err)
1274 return 0;
1276 spin_lock(&hugetlb_lock);
1277 h->nr_overcommit_huge_pages = input;
1278 spin_unlock(&hugetlb_lock);
1280 return count;
1282 HSTATE_ATTR(nr_overcommit_hugepages);
1284 static ssize_t free_hugepages_show(struct kobject *kobj,
1285 struct kobj_attribute *attr, char *buf)
1287 struct hstate *h = kobj_to_hstate(kobj);
1288 return sprintf(buf, "%lu\n", h->free_huge_pages);
1290 HSTATE_ATTR_RO(free_hugepages);
1292 static ssize_t resv_hugepages_show(struct kobject *kobj,
1293 struct kobj_attribute *attr, char *buf)
1295 struct hstate *h = kobj_to_hstate(kobj);
1296 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1298 HSTATE_ATTR_RO(resv_hugepages);
1300 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1301 struct kobj_attribute *attr, char *buf)
1303 struct hstate *h = kobj_to_hstate(kobj);
1304 return sprintf(buf, "%lu\n", h->surplus_huge_pages);
1306 HSTATE_ATTR_RO(surplus_hugepages);
1308 static struct attribute *hstate_attrs[] = {
1309 &nr_hugepages_attr.attr,
1310 &nr_overcommit_hugepages_attr.attr,
1311 &free_hugepages_attr.attr,
1312 &resv_hugepages_attr.attr,
1313 &surplus_hugepages_attr.attr,
1314 NULL,
1317 static struct attribute_group hstate_attr_group = {
1318 .attrs = hstate_attrs,
1321 static int __init hugetlb_sysfs_add_hstate(struct hstate *h)
1323 int retval;
1325 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name,
1326 hugepages_kobj);
1327 if (!hstate_kobjs[h - hstates])
1328 return -ENOMEM;
1330 retval = sysfs_create_group(hstate_kobjs[h - hstates],
1331 &hstate_attr_group);
1332 if (retval)
1333 kobject_put(hstate_kobjs[h - hstates]);
1335 return retval;
1338 static void __init hugetlb_sysfs_init(void)
1340 struct hstate *h;
1341 int err;
1343 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1344 if (!hugepages_kobj)
1345 return;
1347 for_each_hstate(h) {
1348 err = hugetlb_sysfs_add_hstate(h);
1349 if (err)
1350 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1351 h->name);
1355 static void __exit hugetlb_exit(void)
1357 struct hstate *h;
1359 for_each_hstate(h) {
1360 kobject_put(hstate_kobjs[h - hstates]);
1363 kobject_put(hugepages_kobj);
1365 module_exit(hugetlb_exit);
1367 static int __init hugetlb_init(void)
1369 /* Some platform decide whether they support huge pages at boot
1370 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1371 * there is no such support
1373 if (HPAGE_SHIFT == 0)
1374 return 0;
1376 if (!size_to_hstate(default_hstate_size)) {
1377 default_hstate_size = HPAGE_SIZE;
1378 if (!size_to_hstate(default_hstate_size))
1379 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1381 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1382 if (default_hstate_max_huge_pages)
1383 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1385 hugetlb_init_hstates();
1387 gather_bootmem_prealloc();
1389 report_hugepages();
1391 hugetlb_sysfs_init();
1393 return 0;
1395 module_init(hugetlb_init);
1397 /* Should be called on processing a hugepagesz=... option */
1398 void __init hugetlb_add_hstate(unsigned order)
1400 struct hstate *h;
1401 unsigned long i;
1403 if (size_to_hstate(PAGE_SIZE << order)) {
1404 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1405 return;
1407 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1408 BUG_ON(order == 0);
1409 h = &hstates[max_hstate++];
1410 h->order = order;
1411 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1412 h->nr_huge_pages = 0;
1413 h->free_huge_pages = 0;
1414 for (i = 0; i < MAX_NUMNODES; ++i)
1415 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1416 h->hugetlb_next_nid = first_node(node_online_map);
1417 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1418 huge_page_size(h)/1024);
1420 parsed_hstate = h;
1423 static int __init hugetlb_nrpages_setup(char *s)
1425 unsigned long *mhp;
1426 static unsigned long *last_mhp;
1429 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1430 * so this hugepages= parameter goes to the "default hstate".
1432 if (!max_hstate)
1433 mhp = &default_hstate_max_huge_pages;
1434 else
1435 mhp = &parsed_hstate->max_huge_pages;
1437 if (mhp == last_mhp) {
1438 printk(KERN_WARNING "hugepages= specified twice without "
1439 "interleaving hugepagesz=, ignoring\n");
1440 return 1;
1443 if (sscanf(s, "%lu", mhp) <= 0)
1444 *mhp = 0;
1447 * Global state is always initialized later in hugetlb_init.
1448 * But we need to allocate >= MAX_ORDER hstates here early to still
1449 * use the bootmem allocator.
1451 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1452 hugetlb_hstate_alloc_pages(parsed_hstate);
1454 last_mhp = mhp;
1456 return 1;
1458 __setup("hugepages=", hugetlb_nrpages_setup);
1460 static int __init hugetlb_default_setup(char *s)
1462 default_hstate_size = memparse(s, &s);
1463 return 1;
1465 __setup("default_hugepagesz=", hugetlb_default_setup);
1467 static unsigned int cpuset_mems_nr(unsigned int *array)
1469 int node;
1470 unsigned int nr = 0;
1472 for_each_node_mask(node, cpuset_current_mems_allowed)
1473 nr += array[node];
1475 return nr;
1478 #ifdef CONFIG_SYSCTL
1479 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1480 struct file *file, void __user *buffer,
1481 size_t *length, loff_t *ppos)
1483 struct hstate *h = &default_hstate;
1484 unsigned long tmp;
1486 if (!write)
1487 tmp = h->max_huge_pages;
1489 table->data = &tmp;
1490 table->maxlen = sizeof(unsigned long);
1491 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1493 if (write)
1494 h->max_huge_pages = set_max_huge_pages(h, tmp);
1496 return 0;
1499 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1500 struct file *file, void __user *buffer,
1501 size_t *length, loff_t *ppos)
1503 proc_dointvec(table, write, file, buffer, length, ppos);
1504 if (hugepages_treat_as_movable)
1505 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1506 else
1507 htlb_alloc_mask = GFP_HIGHUSER;
1508 return 0;
1511 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1512 struct file *file, void __user *buffer,
1513 size_t *length, loff_t *ppos)
1515 struct hstate *h = &default_hstate;
1516 unsigned long tmp;
1518 if (!write)
1519 tmp = h->nr_overcommit_huge_pages;
1521 table->data = &tmp;
1522 table->maxlen = sizeof(unsigned long);
1523 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1525 if (write) {
1526 spin_lock(&hugetlb_lock);
1527 h->nr_overcommit_huge_pages = tmp;
1528 spin_unlock(&hugetlb_lock);
1531 return 0;
1534 #endif /* CONFIG_SYSCTL */
1536 void hugetlb_report_meminfo(struct seq_file *m)
1538 struct hstate *h = &default_hstate;
1539 seq_printf(m,
1540 "HugePages_Total: %5lu\n"
1541 "HugePages_Free: %5lu\n"
1542 "HugePages_Rsvd: %5lu\n"
1543 "HugePages_Surp: %5lu\n"
1544 "Hugepagesize: %8lu kB\n",
1545 h->nr_huge_pages,
1546 h->free_huge_pages,
1547 h->resv_huge_pages,
1548 h->surplus_huge_pages,
1549 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1552 int hugetlb_report_node_meminfo(int nid, char *buf)
1554 struct hstate *h = &default_hstate;
1555 return sprintf(buf,
1556 "Node %d HugePages_Total: %5u\n"
1557 "Node %d HugePages_Free: %5u\n"
1558 "Node %d HugePages_Surp: %5u\n",
1559 nid, h->nr_huge_pages_node[nid],
1560 nid, h->free_huge_pages_node[nid],
1561 nid, h->surplus_huge_pages_node[nid]);
1564 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1565 unsigned long hugetlb_total_pages(void)
1567 struct hstate *h = &default_hstate;
1568 return h->nr_huge_pages * pages_per_huge_page(h);
1571 static int hugetlb_acct_memory(struct hstate *h, long delta)
1573 int ret = -ENOMEM;
1575 spin_lock(&hugetlb_lock);
1577 * When cpuset is configured, it breaks the strict hugetlb page
1578 * reservation as the accounting is done on a global variable. Such
1579 * reservation is completely rubbish in the presence of cpuset because
1580 * the reservation is not checked against page availability for the
1581 * current cpuset. Application can still potentially OOM'ed by kernel
1582 * with lack of free htlb page in cpuset that the task is in.
1583 * Attempt to enforce strict accounting with cpuset is almost
1584 * impossible (or too ugly) because cpuset is too fluid that
1585 * task or memory node can be dynamically moved between cpusets.
1587 * The change of semantics for shared hugetlb mapping with cpuset is
1588 * undesirable. However, in order to preserve some of the semantics,
1589 * we fall back to check against current free page availability as
1590 * a best attempt and hopefully to minimize the impact of changing
1591 * semantics that cpuset has.
1593 if (delta > 0) {
1594 if (gather_surplus_pages(h, delta) < 0)
1595 goto out;
1597 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1598 return_unused_surplus_pages(h, delta);
1599 goto out;
1603 ret = 0;
1604 if (delta < 0)
1605 return_unused_surplus_pages(h, (unsigned long) -delta);
1607 out:
1608 spin_unlock(&hugetlb_lock);
1609 return ret;
1612 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1614 struct resv_map *reservations = vma_resv_map(vma);
1617 * This new VMA should share its siblings reservation map if present.
1618 * The VMA will only ever have a valid reservation map pointer where
1619 * it is being copied for another still existing VMA. As that VMA
1620 * has a reference to the reservation map it cannot dissappear until
1621 * after this open call completes. It is therefore safe to take a
1622 * new reference here without additional locking.
1624 if (reservations)
1625 kref_get(&reservations->refs);
1628 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1630 struct hstate *h = hstate_vma(vma);
1631 struct resv_map *reservations = vma_resv_map(vma);
1632 unsigned long reserve;
1633 unsigned long start;
1634 unsigned long end;
1636 if (reservations) {
1637 start = vma_hugecache_offset(h, vma, vma->vm_start);
1638 end = vma_hugecache_offset(h, vma, vma->vm_end);
1640 reserve = (end - start) -
1641 region_count(&reservations->regions, start, end);
1643 kref_put(&reservations->refs, resv_map_release);
1645 if (reserve) {
1646 hugetlb_acct_memory(h, -reserve);
1647 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
1653 * We cannot handle pagefaults against hugetlb pages at all. They cause
1654 * handle_mm_fault() to try to instantiate regular-sized pages in the
1655 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1656 * this far.
1658 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1660 BUG();
1661 return 0;
1664 struct vm_operations_struct hugetlb_vm_ops = {
1665 .fault = hugetlb_vm_op_fault,
1666 .open = hugetlb_vm_op_open,
1667 .close = hugetlb_vm_op_close,
1670 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1671 int writable)
1673 pte_t entry;
1675 if (writable) {
1676 entry =
1677 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1678 } else {
1679 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1681 entry = pte_mkyoung(entry);
1682 entry = pte_mkhuge(entry);
1684 return entry;
1687 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1688 unsigned long address, pte_t *ptep)
1690 pte_t entry;
1692 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1693 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1694 update_mmu_cache(vma, address, entry);
1699 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1700 struct vm_area_struct *vma)
1702 pte_t *src_pte, *dst_pte, entry;
1703 struct page *ptepage;
1704 unsigned long addr;
1705 int cow;
1706 struct hstate *h = hstate_vma(vma);
1707 unsigned long sz = huge_page_size(h);
1709 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1711 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1712 src_pte = huge_pte_offset(src, addr);
1713 if (!src_pte)
1714 continue;
1715 dst_pte = huge_pte_alloc(dst, addr, sz);
1716 if (!dst_pte)
1717 goto nomem;
1719 /* If the pagetables are shared don't copy or take references */
1720 if (dst_pte == src_pte)
1721 continue;
1723 spin_lock(&dst->page_table_lock);
1724 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1725 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1726 if (cow)
1727 huge_ptep_set_wrprotect(src, addr, src_pte);
1728 entry = huge_ptep_get(src_pte);
1729 ptepage = pte_page(entry);
1730 get_page(ptepage);
1731 set_huge_pte_at(dst, addr, dst_pte, entry);
1733 spin_unlock(&src->page_table_lock);
1734 spin_unlock(&dst->page_table_lock);
1736 return 0;
1738 nomem:
1739 return -ENOMEM;
1742 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1743 unsigned long end, struct page *ref_page)
1745 struct mm_struct *mm = vma->vm_mm;
1746 unsigned long address;
1747 pte_t *ptep;
1748 pte_t pte;
1749 struct page *page;
1750 struct page *tmp;
1751 struct hstate *h = hstate_vma(vma);
1752 unsigned long sz = huge_page_size(h);
1755 * A page gathering list, protected by per file i_mmap_lock. The
1756 * lock is used to avoid list corruption from multiple unmapping
1757 * of the same page since we are using page->lru.
1759 LIST_HEAD(page_list);
1761 WARN_ON(!is_vm_hugetlb_page(vma));
1762 BUG_ON(start & ~huge_page_mask(h));
1763 BUG_ON(end & ~huge_page_mask(h));
1765 mmu_notifier_invalidate_range_start(mm, start, end);
1766 spin_lock(&mm->page_table_lock);
1767 for (address = start; address < end; address += sz) {
1768 ptep = huge_pte_offset(mm, address);
1769 if (!ptep)
1770 continue;
1772 if (huge_pmd_unshare(mm, &address, ptep))
1773 continue;
1776 * If a reference page is supplied, it is because a specific
1777 * page is being unmapped, not a range. Ensure the page we
1778 * are about to unmap is the actual page of interest.
1780 if (ref_page) {
1781 pte = huge_ptep_get(ptep);
1782 if (huge_pte_none(pte))
1783 continue;
1784 page = pte_page(pte);
1785 if (page != ref_page)
1786 continue;
1789 * Mark the VMA as having unmapped its page so that
1790 * future faults in this VMA will fail rather than
1791 * looking like data was lost
1793 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1796 pte = huge_ptep_get_and_clear(mm, address, ptep);
1797 if (huge_pte_none(pte))
1798 continue;
1800 page = pte_page(pte);
1801 if (pte_dirty(pte))
1802 set_page_dirty(page);
1803 list_add(&page->lru, &page_list);
1805 spin_unlock(&mm->page_table_lock);
1806 flush_tlb_range(vma, start, end);
1807 mmu_notifier_invalidate_range_end(mm, start, end);
1808 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1809 list_del(&page->lru);
1810 put_page(page);
1814 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1815 unsigned long end, struct page *ref_page)
1817 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1818 __unmap_hugepage_range(vma, start, end, ref_page);
1819 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1823 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1824 * mappping it owns the reserve page for. The intention is to unmap the page
1825 * from other VMAs and let the children be SIGKILLed if they are faulting the
1826 * same region.
1828 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
1829 struct page *page, unsigned long address)
1831 struct hstate *h = hstate_vma(vma);
1832 struct vm_area_struct *iter_vma;
1833 struct address_space *mapping;
1834 struct prio_tree_iter iter;
1835 pgoff_t pgoff;
1838 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1839 * from page cache lookup which is in HPAGE_SIZE units.
1841 address = address & huge_page_mask(h);
1842 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1843 + (vma->vm_pgoff >> PAGE_SHIFT);
1844 mapping = (struct address_space *)page_private(page);
1846 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1847 /* Do not unmap the current VMA */
1848 if (iter_vma == vma)
1849 continue;
1852 * Unmap the page from other VMAs without their own reserves.
1853 * They get marked to be SIGKILLed if they fault in these
1854 * areas. This is because a future no-page fault on this VMA
1855 * could insert a zeroed page instead of the data existing
1856 * from the time of fork. This would look like data corruption
1858 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1859 unmap_hugepage_range(iter_vma,
1860 address, address + huge_page_size(h),
1861 page);
1864 return 1;
1867 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1868 unsigned long address, pte_t *ptep, pte_t pte,
1869 struct page *pagecache_page)
1871 struct hstate *h = hstate_vma(vma);
1872 struct page *old_page, *new_page;
1873 int avoidcopy;
1874 int outside_reserve = 0;
1876 old_page = pte_page(pte);
1878 retry_avoidcopy:
1879 /* If no-one else is actually using this page, avoid the copy
1880 * and just make the page writable */
1881 avoidcopy = (page_count(old_page) == 1);
1882 if (avoidcopy) {
1883 set_huge_ptep_writable(vma, address, ptep);
1884 return 0;
1888 * If the process that created a MAP_PRIVATE mapping is about to
1889 * perform a COW due to a shared page count, attempt to satisfy
1890 * the allocation without using the existing reserves. The pagecache
1891 * page is used to determine if the reserve at this address was
1892 * consumed or not. If reserves were used, a partial faulted mapping
1893 * at the time of fork() could consume its reserves on COW instead
1894 * of the full address range.
1896 if (!(vma->vm_flags & VM_SHARED) &&
1897 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1898 old_page != pagecache_page)
1899 outside_reserve = 1;
1901 page_cache_get(old_page);
1902 new_page = alloc_huge_page(vma, address, outside_reserve);
1904 if (IS_ERR(new_page)) {
1905 page_cache_release(old_page);
1908 * If a process owning a MAP_PRIVATE mapping fails to COW,
1909 * it is due to references held by a child and an insufficient
1910 * huge page pool. To guarantee the original mappers
1911 * reliability, unmap the page from child processes. The child
1912 * may get SIGKILLed if it later faults.
1914 if (outside_reserve) {
1915 BUG_ON(huge_pte_none(pte));
1916 if (unmap_ref_private(mm, vma, old_page, address)) {
1917 BUG_ON(page_count(old_page) != 1);
1918 BUG_ON(huge_pte_none(pte));
1919 goto retry_avoidcopy;
1921 WARN_ON_ONCE(1);
1924 return -PTR_ERR(new_page);
1927 spin_unlock(&mm->page_table_lock);
1928 copy_huge_page(new_page, old_page, address, vma);
1929 __SetPageUptodate(new_page);
1930 spin_lock(&mm->page_table_lock);
1932 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
1933 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
1934 /* Break COW */
1935 huge_ptep_clear_flush(vma, address, ptep);
1936 set_huge_pte_at(mm, address, ptep,
1937 make_huge_pte(vma, new_page, 1));
1938 /* Make the old page be freed below */
1939 new_page = old_page;
1941 page_cache_release(new_page);
1942 page_cache_release(old_page);
1943 return 0;
1946 /* Return the pagecache page at a given address within a VMA */
1947 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
1948 struct vm_area_struct *vma, unsigned long address)
1950 struct address_space *mapping;
1951 pgoff_t idx;
1953 mapping = vma->vm_file->f_mapping;
1954 idx = vma_hugecache_offset(h, vma, address);
1956 return find_lock_page(mapping, idx);
1959 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1960 unsigned long address, pte_t *ptep, int write_access)
1962 struct hstate *h = hstate_vma(vma);
1963 int ret = VM_FAULT_SIGBUS;
1964 pgoff_t idx;
1965 unsigned long size;
1966 struct page *page;
1967 struct address_space *mapping;
1968 pte_t new_pte;
1971 * Currently, we are forced to kill the process in the event the
1972 * original mapper has unmapped pages from the child due to a failed
1973 * COW. Warn that such a situation has occured as it may not be obvious
1975 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
1976 printk(KERN_WARNING
1977 "PID %d killed due to inadequate hugepage pool\n",
1978 current->pid);
1979 return ret;
1982 mapping = vma->vm_file->f_mapping;
1983 idx = vma_hugecache_offset(h, vma, address);
1986 * Use page lock to guard against racing truncation
1987 * before we get page_table_lock.
1989 retry:
1990 page = find_lock_page(mapping, idx);
1991 if (!page) {
1992 size = i_size_read(mapping->host) >> huge_page_shift(h);
1993 if (idx >= size)
1994 goto out;
1995 page = alloc_huge_page(vma, address, 0);
1996 if (IS_ERR(page)) {
1997 ret = -PTR_ERR(page);
1998 goto out;
2000 clear_huge_page(page, address, huge_page_size(h));
2001 __SetPageUptodate(page);
2003 if (vma->vm_flags & VM_SHARED) {
2004 int err;
2005 struct inode *inode = mapping->host;
2007 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2008 if (err) {
2009 put_page(page);
2010 if (err == -EEXIST)
2011 goto retry;
2012 goto out;
2015 spin_lock(&inode->i_lock);
2016 inode->i_blocks += blocks_per_huge_page(h);
2017 spin_unlock(&inode->i_lock);
2018 } else
2019 lock_page(page);
2023 * If we are going to COW a private mapping later, we examine the
2024 * pending reservations for this page now. This will ensure that
2025 * any allocations necessary to record that reservation occur outside
2026 * the spinlock.
2028 if (write_access && !(vma->vm_flags & VM_SHARED))
2029 if (vma_needs_reservation(h, vma, address) < 0) {
2030 ret = VM_FAULT_OOM;
2031 goto backout_unlocked;
2034 spin_lock(&mm->page_table_lock);
2035 size = i_size_read(mapping->host) >> huge_page_shift(h);
2036 if (idx >= size)
2037 goto backout;
2039 ret = 0;
2040 if (!huge_pte_none(huge_ptep_get(ptep)))
2041 goto backout;
2043 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2044 && (vma->vm_flags & VM_SHARED)));
2045 set_huge_pte_at(mm, address, ptep, new_pte);
2047 if (write_access && !(vma->vm_flags & VM_SHARED)) {
2048 /* Optimization, do the COW without a second fault */
2049 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2052 spin_unlock(&mm->page_table_lock);
2053 unlock_page(page);
2054 out:
2055 return ret;
2057 backout:
2058 spin_unlock(&mm->page_table_lock);
2059 backout_unlocked:
2060 unlock_page(page);
2061 put_page(page);
2062 goto out;
2065 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2066 unsigned long address, int write_access)
2068 pte_t *ptep;
2069 pte_t entry;
2070 int ret;
2071 struct page *pagecache_page = NULL;
2072 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2073 struct hstate *h = hstate_vma(vma);
2075 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2076 if (!ptep)
2077 return VM_FAULT_OOM;
2080 * Serialize hugepage allocation and instantiation, so that we don't
2081 * get spurious allocation failures if two CPUs race to instantiate
2082 * the same page in the page cache.
2084 mutex_lock(&hugetlb_instantiation_mutex);
2085 entry = huge_ptep_get(ptep);
2086 if (huge_pte_none(entry)) {
2087 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
2088 goto out_mutex;
2091 ret = 0;
2094 * If we are going to COW the mapping later, we examine the pending
2095 * reservations for this page now. This will ensure that any
2096 * allocations necessary to record that reservation occur outside the
2097 * spinlock. For private mappings, we also lookup the pagecache
2098 * page now as it is used to determine if a reservation has been
2099 * consumed.
2101 if (write_access && !pte_write(entry)) {
2102 if (vma_needs_reservation(h, vma, address) < 0) {
2103 ret = VM_FAULT_OOM;
2104 goto out_mutex;
2107 if (!(vma->vm_flags & VM_SHARED))
2108 pagecache_page = hugetlbfs_pagecache_page(h,
2109 vma, address);
2112 spin_lock(&mm->page_table_lock);
2113 /* Check for a racing update before calling hugetlb_cow */
2114 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2115 goto out_page_table_lock;
2118 if (write_access) {
2119 if (!pte_write(entry)) {
2120 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2121 pagecache_page);
2122 goto out_page_table_lock;
2124 entry = pte_mkdirty(entry);
2126 entry = pte_mkyoung(entry);
2127 if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access))
2128 update_mmu_cache(vma, address, entry);
2130 out_page_table_lock:
2131 spin_unlock(&mm->page_table_lock);
2133 if (pagecache_page) {
2134 unlock_page(pagecache_page);
2135 put_page(pagecache_page);
2138 out_mutex:
2139 mutex_unlock(&hugetlb_instantiation_mutex);
2141 return ret;
2144 /* Can be overriden by architectures */
2145 __attribute__((weak)) struct page *
2146 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2147 pud_t *pud, int write)
2149 BUG();
2150 return NULL;
2153 static int huge_zeropage_ok(pte_t *ptep, int write, int shared)
2155 if (!ptep || write || shared)
2156 return 0;
2157 else
2158 return huge_pte_none(huge_ptep_get(ptep));
2161 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2162 struct page **pages, struct vm_area_struct **vmas,
2163 unsigned long *position, int *length, int i,
2164 int write)
2166 unsigned long pfn_offset;
2167 unsigned long vaddr = *position;
2168 int remainder = *length;
2169 struct hstate *h = hstate_vma(vma);
2170 int zeropage_ok = 0;
2171 int shared = vma->vm_flags & VM_SHARED;
2173 spin_lock(&mm->page_table_lock);
2174 while (vaddr < vma->vm_end && remainder) {
2175 pte_t *pte;
2176 struct page *page;
2179 * Some archs (sparc64, sh*) have multiple pte_ts to
2180 * each hugepage. We have to make * sure we get the
2181 * first, for the page indexing below to work.
2183 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2184 if (huge_zeropage_ok(pte, write, shared))
2185 zeropage_ok = 1;
2187 if (!pte ||
2188 (huge_pte_none(huge_ptep_get(pte)) && !zeropage_ok) ||
2189 (write && !pte_write(huge_ptep_get(pte)))) {
2190 int ret;
2192 spin_unlock(&mm->page_table_lock);
2193 ret = hugetlb_fault(mm, vma, vaddr, write);
2194 spin_lock(&mm->page_table_lock);
2195 if (!(ret & VM_FAULT_ERROR))
2196 continue;
2198 remainder = 0;
2199 if (!i)
2200 i = -EFAULT;
2201 break;
2204 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2205 page = pte_page(huge_ptep_get(pte));
2206 same_page:
2207 if (pages) {
2208 if (zeropage_ok)
2209 pages[i] = ZERO_PAGE(0);
2210 else
2211 pages[i] = mem_map_offset(page, pfn_offset);
2212 get_page(pages[i]);
2215 if (vmas)
2216 vmas[i] = vma;
2218 vaddr += PAGE_SIZE;
2219 ++pfn_offset;
2220 --remainder;
2221 ++i;
2222 if (vaddr < vma->vm_end && remainder &&
2223 pfn_offset < pages_per_huge_page(h)) {
2225 * We use pfn_offset to avoid touching the pageframes
2226 * of this compound page.
2228 goto same_page;
2231 spin_unlock(&mm->page_table_lock);
2232 *length = remainder;
2233 *position = vaddr;
2235 return i;
2238 void hugetlb_change_protection(struct vm_area_struct *vma,
2239 unsigned long address, unsigned long end, pgprot_t newprot)
2241 struct mm_struct *mm = vma->vm_mm;
2242 unsigned long start = address;
2243 pte_t *ptep;
2244 pte_t pte;
2245 struct hstate *h = hstate_vma(vma);
2247 BUG_ON(address >= end);
2248 flush_cache_range(vma, address, end);
2250 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2251 spin_lock(&mm->page_table_lock);
2252 for (; address < end; address += huge_page_size(h)) {
2253 ptep = huge_pte_offset(mm, address);
2254 if (!ptep)
2255 continue;
2256 if (huge_pmd_unshare(mm, &address, ptep))
2257 continue;
2258 if (!huge_pte_none(huge_ptep_get(ptep))) {
2259 pte = huge_ptep_get_and_clear(mm, address, ptep);
2260 pte = pte_mkhuge(pte_modify(pte, newprot));
2261 set_huge_pte_at(mm, address, ptep, pte);
2264 spin_unlock(&mm->page_table_lock);
2265 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2267 flush_tlb_range(vma, start, end);
2270 int hugetlb_reserve_pages(struct inode *inode,
2271 long from, long to,
2272 struct vm_area_struct *vma,
2273 int acctflag)
2275 long ret, chg;
2276 struct hstate *h = hstate_inode(inode);
2279 * Only apply hugepage reservation if asked. At fault time, an
2280 * attempt will be made for VM_NORESERVE to allocate a page
2281 * and filesystem quota without using reserves
2283 if (acctflag & VM_NORESERVE)
2284 return 0;
2287 * Shared mappings base their reservation on the number of pages that
2288 * are already allocated on behalf of the file. Private mappings need
2289 * to reserve the full area even if read-only as mprotect() may be
2290 * called to make the mapping read-write. Assume !vma is a shm mapping
2292 if (!vma || vma->vm_flags & VM_SHARED)
2293 chg = region_chg(&inode->i_mapping->private_list, from, to);
2294 else {
2295 struct resv_map *resv_map = resv_map_alloc();
2296 if (!resv_map)
2297 return -ENOMEM;
2299 chg = to - from;
2301 set_vma_resv_map(vma, resv_map);
2302 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2305 if (chg < 0)
2306 return chg;
2308 /* There must be enough filesystem quota for the mapping */
2309 if (hugetlb_get_quota(inode->i_mapping, chg))
2310 return -ENOSPC;
2313 * Check enough hugepages are available for the reservation.
2314 * Hand back the quota if there are not
2316 ret = hugetlb_acct_memory(h, chg);
2317 if (ret < 0) {
2318 hugetlb_put_quota(inode->i_mapping, chg);
2319 return ret;
2323 * Account for the reservations made. Shared mappings record regions
2324 * that have reservations as they are shared by multiple VMAs.
2325 * When the last VMA disappears, the region map says how much
2326 * the reservation was and the page cache tells how much of
2327 * the reservation was consumed. Private mappings are per-VMA and
2328 * only the consumed reservations are tracked. When the VMA
2329 * disappears, the original reservation is the VMA size and the
2330 * consumed reservations are stored in the map. Hence, nothing
2331 * else has to be done for private mappings here
2333 if (!vma || vma->vm_flags & VM_SHARED)
2334 region_add(&inode->i_mapping->private_list, from, to);
2335 return 0;
2338 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2340 struct hstate *h = hstate_inode(inode);
2341 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2343 spin_lock(&inode->i_lock);
2344 inode->i_blocks -= blocks_per_huge_page(h);
2345 spin_unlock(&inode->i_lock);
2347 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2348 hugetlb_acct_memory(h, -(chg - freed));