Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / hugetlb.c
blob5d7601b0287487321314c1d969f17425b339f9b1
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);
237 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
240 * Return the page size being used by the MMU to back a VMA. In the majority
241 * of cases, the page size used by the kernel matches the MMU size. On
242 * architectures where it differs, an architecture-specific version of this
243 * function is required.
245 #ifndef vma_mmu_pagesize
246 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
248 return vma_kernel_pagesize(vma);
250 #endif
253 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
254 * bits of the reservation map pointer, which are always clear due to
255 * alignment.
257 #define HPAGE_RESV_OWNER (1UL << 0)
258 #define HPAGE_RESV_UNMAPPED (1UL << 1)
259 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
262 * These helpers are used to track how many pages are reserved for
263 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
264 * is guaranteed to have their future faults succeed.
266 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
267 * the reserve counters are updated with the hugetlb_lock held. It is safe
268 * to reset the VMA at fork() time as it is not in use yet and there is no
269 * chance of the global counters getting corrupted as a result of the values.
271 * The private mapping reservation is represented in a subtly different
272 * manner to a shared mapping. A shared mapping has a region map associated
273 * with the underlying file, this region map represents the backing file
274 * pages which have ever had a reservation assigned which this persists even
275 * after the page is instantiated. A private mapping has a region map
276 * associated with the original mmap which is attached to all VMAs which
277 * reference it, this region map represents those offsets which have consumed
278 * reservation ie. where pages have been instantiated.
280 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
282 return (unsigned long)vma->vm_private_data;
285 static void set_vma_private_data(struct vm_area_struct *vma,
286 unsigned long value)
288 vma->vm_private_data = (void *)value;
291 struct resv_map {
292 struct kref refs;
293 struct list_head regions;
296 static struct resv_map *resv_map_alloc(void)
298 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
299 if (!resv_map)
300 return NULL;
302 kref_init(&resv_map->refs);
303 INIT_LIST_HEAD(&resv_map->regions);
305 return resv_map;
308 static void resv_map_release(struct kref *ref)
310 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
312 /* Clear out any active regions before we release the map. */
313 region_truncate(&resv_map->regions, 0);
314 kfree(resv_map);
317 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
319 VM_BUG_ON(!is_vm_hugetlb_page(vma));
320 if (!(vma->vm_flags & VM_MAYSHARE))
321 return (struct resv_map *)(get_vma_private_data(vma) &
322 ~HPAGE_RESV_MASK);
323 return NULL;
326 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
328 VM_BUG_ON(!is_vm_hugetlb_page(vma));
329 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
331 set_vma_private_data(vma, (get_vma_private_data(vma) &
332 HPAGE_RESV_MASK) | (unsigned long)map);
335 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
337 VM_BUG_ON(!is_vm_hugetlb_page(vma));
338 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
340 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
343 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
345 VM_BUG_ON(!is_vm_hugetlb_page(vma));
347 return (get_vma_private_data(vma) & flag) != 0;
350 /* Decrement the reserved pages in the hugepage pool by one */
351 static void decrement_hugepage_resv_vma(struct hstate *h,
352 struct vm_area_struct *vma)
354 if (vma->vm_flags & VM_NORESERVE)
355 return;
357 if (vma->vm_flags & VM_MAYSHARE) {
358 /* Shared mappings always use reserves */
359 h->resv_huge_pages--;
360 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
362 * Only the process that called mmap() has reserves for
363 * private mappings.
365 h->resv_huge_pages--;
369 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
370 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
372 VM_BUG_ON(!is_vm_hugetlb_page(vma));
373 if (!(vma->vm_flags & VM_MAYSHARE))
374 vma->vm_private_data = (void *)0;
377 /* Returns true if the VMA has associated reserve pages */
378 static int vma_has_reserves(struct vm_area_struct *vma)
380 if (vma->vm_flags & VM_MAYSHARE)
381 return 1;
382 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
383 return 1;
384 return 0;
387 static void clear_gigantic_page(struct page *page,
388 unsigned long addr, unsigned long sz)
390 int i;
391 struct page *p = page;
393 might_sleep();
394 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
395 cond_resched();
396 clear_user_highpage(p, addr + i * PAGE_SIZE);
399 static void clear_huge_page(struct page *page,
400 unsigned long addr, unsigned long sz)
402 int i;
404 if (unlikely(sz > MAX_ORDER_NR_PAGES)) {
405 clear_gigantic_page(page, addr, sz);
406 return;
409 might_sleep();
410 for (i = 0; i < sz/PAGE_SIZE; i++) {
411 cond_resched();
412 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
416 static void copy_gigantic_page(struct page *dst, struct page *src,
417 unsigned long addr, struct vm_area_struct *vma)
419 int i;
420 struct hstate *h = hstate_vma(vma);
421 struct page *dst_base = dst;
422 struct page *src_base = src;
423 might_sleep();
424 for (i = 0; i < pages_per_huge_page(h); ) {
425 cond_resched();
426 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
428 i++;
429 dst = mem_map_next(dst, dst_base, i);
430 src = mem_map_next(src, src_base, i);
433 static void copy_huge_page(struct page *dst, struct page *src,
434 unsigned long addr, struct vm_area_struct *vma)
436 int i;
437 struct hstate *h = hstate_vma(vma);
439 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
440 copy_gigantic_page(dst, src, addr, vma);
441 return;
444 might_sleep();
445 for (i = 0; i < pages_per_huge_page(h); i++) {
446 cond_resched();
447 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
451 static void enqueue_huge_page(struct hstate *h, struct page *page)
453 int nid = page_to_nid(page);
454 list_add(&page->lru, &h->hugepage_freelists[nid]);
455 h->free_huge_pages++;
456 h->free_huge_pages_node[nid]++;
459 static struct page *dequeue_huge_page_vma(struct hstate *h,
460 struct vm_area_struct *vma,
461 unsigned long address, int avoid_reserve)
463 int nid;
464 struct page *page = NULL;
465 struct mempolicy *mpol;
466 nodemask_t *nodemask;
467 struct zonelist *zonelist = huge_zonelist(vma, address,
468 htlb_alloc_mask, &mpol, &nodemask);
469 struct zone *zone;
470 struct zoneref *z;
473 * A child process with MAP_PRIVATE mappings created by their parent
474 * have no page reserves. This check ensures that reservations are
475 * not "stolen". The child may still get SIGKILLed
477 if (!vma_has_reserves(vma) &&
478 h->free_huge_pages - h->resv_huge_pages == 0)
479 return NULL;
481 /* If reserves cannot be used, ensure enough pages are in the pool */
482 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
483 return NULL;
485 for_each_zone_zonelist_nodemask(zone, z, zonelist,
486 MAX_NR_ZONES - 1, nodemask) {
487 nid = zone_to_nid(zone);
488 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
489 !list_empty(&h->hugepage_freelists[nid])) {
490 page = list_entry(h->hugepage_freelists[nid].next,
491 struct page, lru);
492 list_del(&page->lru);
493 h->free_huge_pages--;
494 h->free_huge_pages_node[nid]--;
496 if (!avoid_reserve)
497 decrement_hugepage_resv_vma(h, vma);
499 break;
502 mpol_cond_put(mpol);
503 return page;
506 static void update_and_free_page(struct hstate *h, struct page *page)
508 int i;
510 VM_BUG_ON(h->order >= MAX_ORDER);
512 h->nr_huge_pages--;
513 h->nr_huge_pages_node[page_to_nid(page)]--;
514 for (i = 0; i < pages_per_huge_page(h); i++) {
515 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
516 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
517 1 << PG_private | 1<< PG_writeback);
519 set_compound_page_dtor(page, NULL);
520 set_page_refcounted(page);
521 arch_release_hugepage(page);
522 __free_pages(page, huge_page_order(h));
525 struct hstate *size_to_hstate(unsigned long size)
527 struct hstate *h;
529 for_each_hstate(h) {
530 if (huge_page_size(h) == size)
531 return h;
533 return NULL;
536 static void free_huge_page(struct page *page)
539 * Can't pass hstate in here because it is called from the
540 * compound page destructor.
542 struct hstate *h = page_hstate(page);
543 int nid = page_to_nid(page);
544 struct address_space *mapping;
546 mapping = (struct address_space *) page_private(page);
547 set_page_private(page, 0);
548 BUG_ON(page_count(page));
549 INIT_LIST_HEAD(&page->lru);
551 spin_lock(&hugetlb_lock);
552 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
553 update_and_free_page(h, page);
554 h->surplus_huge_pages--;
555 h->surplus_huge_pages_node[nid]--;
556 } else {
557 enqueue_huge_page(h, page);
559 spin_unlock(&hugetlb_lock);
560 if (mapping)
561 hugetlb_put_quota(mapping, 1);
564 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
566 set_compound_page_dtor(page, free_huge_page);
567 spin_lock(&hugetlb_lock);
568 h->nr_huge_pages++;
569 h->nr_huge_pages_node[nid]++;
570 spin_unlock(&hugetlb_lock);
571 put_page(page); /* free it into the hugepage allocator */
574 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
576 int i;
577 int nr_pages = 1 << order;
578 struct page *p = page + 1;
580 /* we rely on prep_new_huge_page to set the destructor */
581 set_compound_order(page, order);
582 __SetPageHead(page);
583 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
584 __SetPageTail(p);
585 p->first_page = page;
589 int PageHuge(struct page *page)
591 compound_page_dtor *dtor;
593 if (!PageCompound(page))
594 return 0;
596 page = compound_head(page);
597 dtor = get_compound_page_dtor(page);
599 return dtor == free_huge_page;
602 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
604 struct page *page;
606 if (h->order >= MAX_ORDER)
607 return NULL;
609 page = alloc_pages_exact_node(nid,
610 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
611 __GFP_REPEAT|__GFP_NOWARN,
612 huge_page_order(h));
613 if (page) {
614 if (arch_prepare_hugepage(page)) {
615 __free_pages(page, huge_page_order(h));
616 return NULL;
618 prep_new_huge_page(h, page, nid);
621 return page;
625 * Use a helper variable to find the next node and then
626 * copy it back to next_nid_to_alloc afterwards:
627 * otherwise there's a window in which a racer might
628 * pass invalid nid MAX_NUMNODES to alloc_pages_exact_node.
629 * But we don't need to use a spin_lock here: it really
630 * doesn't matter if occasionally a racer chooses the
631 * same nid as we do. Move nid forward in the mask even
632 * if we just successfully allocated a hugepage so that
633 * the next caller gets hugepages on the next node.
635 static int hstate_next_node_to_alloc(struct hstate *h)
637 int next_nid;
638 next_nid = next_node(h->next_nid_to_alloc, node_online_map);
639 if (next_nid == MAX_NUMNODES)
640 next_nid = first_node(node_online_map);
641 h->next_nid_to_alloc = next_nid;
642 return next_nid;
645 static int alloc_fresh_huge_page(struct hstate *h)
647 struct page *page;
648 int start_nid;
649 int next_nid;
650 int ret = 0;
652 start_nid = h->next_nid_to_alloc;
653 next_nid = start_nid;
655 do {
656 page = alloc_fresh_huge_page_node(h, next_nid);
657 if (page)
658 ret = 1;
659 next_nid = hstate_next_node_to_alloc(h);
660 } while (!page && next_nid != start_nid);
662 if (ret)
663 count_vm_event(HTLB_BUDDY_PGALLOC);
664 else
665 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
667 return ret;
671 * helper for free_pool_huge_page() - find next node
672 * from which to free a huge page
674 static int hstate_next_node_to_free(struct hstate *h)
676 int next_nid;
677 next_nid = next_node(h->next_nid_to_free, node_online_map);
678 if (next_nid == MAX_NUMNODES)
679 next_nid = first_node(node_online_map);
680 h->next_nid_to_free = next_nid;
681 return next_nid;
685 * Free huge page from pool from next node to free.
686 * Attempt to keep persistent huge pages more or less
687 * balanced over allowed nodes.
688 * Called with hugetlb_lock locked.
690 static int free_pool_huge_page(struct hstate *h, bool acct_surplus)
692 int start_nid;
693 int next_nid;
694 int ret = 0;
696 start_nid = h->next_nid_to_free;
697 next_nid = start_nid;
699 do {
701 * If we're returning unused surplus pages, only examine
702 * nodes with surplus pages.
704 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
705 !list_empty(&h->hugepage_freelists[next_nid])) {
706 struct page *page =
707 list_entry(h->hugepage_freelists[next_nid].next,
708 struct page, lru);
709 list_del(&page->lru);
710 h->free_huge_pages--;
711 h->free_huge_pages_node[next_nid]--;
712 if (acct_surplus) {
713 h->surplus_huge_pages--;
714 h->surplus_huge_pages_node[next_nid]--;
716 update_and_free_page(h, page);
717 ret = 1;
719 next_nid = hstate_next_node_to_free(h);
720 } while (!ret && next_nid != start_nid);
722 return ret;
725 static struct page *alloc_buddy_huge_page(struct hstate *h,
726 struct vm_area_struct *vma, unsigned long address)
728 struct page *page;
729 unsigned int nid;
731 if (h->order >= MAX_ORDER)
732 return NULL;
735 * Assume we will successfully allocate the surplus page to
736 * prevent racing processes from causing the surplus to exceed
737 * overcommit
739 * This however introduces a different race, where a process B
740 * tries to grow the static hugepage pool while alloc_pages() is
741 * called by process A. B will only examine the per-node
742 * counters in determining if surplus huge pages can be
743 * converted to normal huge pages in adjust_pool_surplus(). A
744 * won't be able to increment the per-node counter, until the
745 * lock is dropped by B, but B doesn't drop hugetlb_lock until
746 * no more huge pages can be converted from surplus to normal
747 * state (and doesn't try to convert again). Thus, we have a
748 * case where a surplus huge page exists, the pool is grown, and
749 * the surplus huge page still exists after, even though it
750 * should just have been converted to a normal huge page. This
751 * does not leak memory, though, as the hugepage will be freed
752 * once it is out of use. It also does not allow the counters to
753 * go out of whack in adjust_pool_surplus() as we don't modify
754 * the node values until we've gotten the hugepage and only the
755 * per-node value is checked there.
757 spin_lock(&hugetlb_lock);
758 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
759 spin_unlock(&hugetlb_lock);
760 return NULL;
761 } else {
762 h->nr_huge_pages++;
763 h->surplus_huge_pages++;
765 spin_unlock(&hugetlb_lock);
767 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
768 __GFP_REPEAT|__GFP_NOWARN,
769 huge_page_order(h));
771 if (page && arch_prepare_hugepage(page)) {
772 __free_pages(page, huge_page_order(h));
773 return NULL;
776 spin_lock(&hugetlb_lock);
777 if (page) {
779 * This page is now managed by the hugetlb allocator and has
780 * no users -- drop the buddy allocator's reference.
782 put_page_testzero(page);
783 VM_BUG_ON(page_count(page));
784 nid = page_to_nid(page);
785 set_compound_page_dtor(page, free_huge_page);
787 * We incremented the global counters already
789 h->nr_huge_pages_node[nid]++;
790 h->surplus_huge_pages_node[nid]++;
791 __count_vm_event(HTLB_BUDDY_PGALLOC);
792 } else {
793 h->nr_huge_pages--;
794 h->surplus_huge_pages--;
795 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
797 spin_unlock(&hugetlb_lock);
799 return page;
803 * Increase the hugetlb pool such that it can accomodate a reservation
804 * of size 'delta'.
806 static int gather_surplus_pages(struct hstate *h, int delta)
808 struct list_head surplus_list;
809 struct page *page, *tmp;
810 int ret, i;
811 int needed, allocated;
813 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
814 if (needed <= 0) {
815 h->resv_huge_pages += delta;
816 return 0;
819 allocated = 0;
820 INIT_LIST_HEAD(&surplus_list);
822 ret = -ENOMEM;
823 retry:
824 spin_unlock(&hugetlb_lock);
825 for (i = 0; i < needed; i++) {
826 page = alloc_buddy_huge_page(h, NULL, 0);
827 if (!page) {
829 * We were not able to allocate enough pages to
830 * satisfy the entire reservation so we free what
831 * we've allocated so far.
833 spin_lock(&hugetlb_lock);
834 needed = 0;
835 goto free;
838 list_add(&page->lru, &surplus_list);
840 allocated += needed;
843 * After retaking hugetlb_lock, we need to recalculate 'needed'
844 * because either resv_huge_pages or free_huge_pages may have changed.
846 spin_lock(&hugetlb_lock);
847 needed = (h->resv_huge_pages + delta) -
848 (h->free_huge_pages + allocated);
849 if (needed > 0)
850 goto retry;
853 * The surplus_list now contains _at_least_ the number of extra pages
854 * needed to accomodate the reservation. Add the appropriate number
855 * of pages to the hugetlb pool and free the extras back to the buddy
856 * allocator. Commit the entire reservation here to prevent another
857 * process from stealing the pages as they are added to the pool but
858 * before they are reserved.
860 needed += allocated;
861 h->resv_huge_pages += delta;
862 ret = 0;
863 free:
864 /* Free the needed pages to the hugetlb pool */
865 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
866 if ((--needed) < 0)
867 break;
868 list_del(&page->lru);
869 enqueue_huge_page(h, page);
872 /* Free unnecessary surplus pages to the buddy allocator */
873 if (!list_empty(&surplus_list)) {
874 spin_unlock(&hugetlb_lock);
875 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
876 list_del(&page->lru);
878 * The page has a reference count of zero already, so
879 * call free_huge_page directly instead of using
880 * put_page. This must be done with hugetlb_lock
881 * unlocked which is safe because free_huge_page takes
882 * hugetlb_lock before deciding how to free the page.
884 free_huge_page(page);
886 spin_lock(&hugetlb_lock);
889 return ret;
893 * When releasing a hugetlb pool reservation, any surplus pages that were
894 * allocated to satisfy the reservation must be explicitly freed if they were
895 * never used.
896 * Called with hugetlb_lock held.
898 static void return_unused_surplus_pages(struct hstate *h,
899 unsigned long unused_resv_pages)
901 unsigned long nr_pages;
903 /* Uncommit the reservation */
904 h->resv_huge_pages -= unused_resv_pages;
906 /* Cannot return gigantic pages currently */
907 if (h->order >= MAX_ORDER)
908 return;
910 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
913 * We want to release as many surplus pages as possible, spread
914 * evenly across all nodes. Iterate across all nodes until we
915 * can no longer free unreserved surplus pages. This occurs when
916 * the nodes with surplus pages have no free pages.
917 * free_pool_huge_page() will balance the the frees across the
918 * on-line nodes for us and will handle the hstate accounting.
920 while (nr_pages--) {
921 if (!free_pool_huge_page(h, 1))
922 break;
927 * Determine if the huge page at addr within the vma has an associated
928 * reservation. Where it does not we will need to logically increase
929 * reservation and actually increase quota before an allocation can occur.
930 * Where any new reservation would be required the reservation change is
931 * prepared, but not committed. Once the page has been quota'd allocated
932 * an instantiated the change should be committed via vma_commit_reservation.
933 * No action is required on failure.
935 static long vma_needs_reservation(struct hstate *h,
936 struct vm_area_struct *vma, unsigned long addr)
938 struct address_space *mapping = vma->vm_file->f_mapping;
939 struct inode *inode = mapping->host;
941 if (vma->vm_flags & VM_MAYSHARE) {
942 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
943 return region_chg(&inode->i_mapping->private_list,
944 idx, idx + 1);
946 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
947 return 1;
949 } else {
950 long err;
951 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
952 struct resv_map *reservations = vma_resv_map(vma);
954 err = region_chg(&reservations->regions, idx, idx + 1);
955 if (err < 0)
956 return err;
957 return 0;
960 static void vma_commit_reservation(struct hstate *h,
961 struct vm_area_struct *vma, unsigned long addr)
963 struct address_space *mapping = vma->vm_file->f_mapping;
964 struct inode *inode = mapping->host;
966 if (vma->vm_flags & VM_MAYSHARE) {
967 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
968 region_add(&inode->i_mapping->private_list, idx, idx + 1);
970 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
971 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
972 struct resv_map *reservations = vma_resv_map(vma);
974 /* Mark this page used in the map. */
975 region_add(&reservations->regions, idx, idx + 1);
979 static struct page *alloc_huge_page(struct vm_area_struct *vma,
980 unsigned long addr, int avoid_reserve)
982 struct hstate *h = hstate_vma(vma);
983 struct page *page;
984 struct address_space *mapping = vma->vm_file->f_mapping;
985 struct inode *inode = mapping->host;
986 long chg;
989 * Processes that did not create the mapping will have no reserves and
990 * will not have accounted against quota. Check that the quota can be
991 * made before satisfying the allocation
992 * MAP_NORESERVE mappings may also need pages and quota allocated
993 * if no reserve mapping overlaps.
995 chg = vma_needs_reservation(h, vma, addr);
996 if (chg < 0)
997 return ERR_PTR(chg);
998 if (chg)
999 if (hugetlb_get_quota(inode->i_mapping, chg))
1000 return ERR_PTR(-ENOSPC);
1002 spin_lock(&hugetlb_lock);
1003 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1004 spin_unlock(&hugetlb_lock);
1006 if (!page) {
1007 page = alloc_buddy_huge_page(h, vma, addr);
1008 if (!page) {
1009 hugetlb_put_quota(inode->i_mapping, chg);
1010 return ERR_PTR(-VM_FAULT_OOM);
1014 set_page_refcounted(page);
1015 set_page_private(page, (unsigned long) mapping);
1017 vma_commit_reservation(h, vma, addr);
1019 return page;
1022 int __weak alloc_bootmem_huge_page(struct hstate *h)
1024 struct huge_bootmem_page *m;
1025 int nr_nodes = nodes_weight(node_online_map);
1027 while (nr_nodes) {
1028 void *addr;
1030 addr = __alloc_bootmem_node_nopanic(
1031 NODE_DATA(h->next_nid_to_alloc),
1032 huge_page_size(h), huge_page_size(h), 0);
1034 hstate_next_node_to_alloc(h);
1035 if (addr) {
1037 * Use the beginning of the huge page to store the
1038 * huge_bootmem_page struct (until gather_bootmem
1039 * puts them into the mem_map).
1041 m = addr;
1042 goto found;
1044 nr_nodes--;
1046 return 0;
1048 found:
1049 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1050 /* Put them into a private list first because mem_map is not up yet */
1051 list_add(&m->list, &huge_boot_pages);
1052 m->hstate = h;
1053 return 1;
1056 static void prep_compound_huge_page(struct page *page, int order)
1058 if (unlikely(order > (MAX_ORDER - 1)))
1059 prep_compound_gigantic_page(page, order);
1060 else
1061 prep_compound_page(page, order);
1064 /* Put bootmem huge pages into the standard lists after mem_map is up */
1065 static void __init gather_bootmem_prealloc(void)
1067 struct huge_bootmem_page *m;
1069 list_for_each_entry(m, &huge_boot_pages, list) {
1070 struct page *page = virt_to_page(m);
1071 struct hstate *h = m->hstate;
1072 __ClearPageReserved(page);
1073 WARN_ON(page_count(page) != 1);
1074 prep_compound_huge_page(page, h->order);
1075 prep_new_huge_page(h, page, page_to_nid(page));
1079 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1081 unsigned long i;
1083 for (i = 0; i < h->max_huge_pages; ++i) {
1084 if (h->order >= MAX_ORDER) {
1085 if (!alloc_bootmem_huge_page(h))
1086 break;
1087 } else if (!alloc_fresh_huge_page(h))
1088 break;
1090 h->max_huge_pages = i;
1093 static void __init hugetlb_init_hstates(void)
1095 struct hstate *h;
1097 for_each_hstate(h) {
1098 /* oversize hugepages were init'ed in early boot */
1099 if (h->order < MAX_ORDER)
1100 hugetlb_hstate_alloc_pages(h);
1104 static char * __init memfmt(char *buf, unsigned long n)
1106 if (n >= (1UL << 30))
1107 sprintf(buf, "%lu GB", n >> 30);
1108 else if (n >= (1UL << 20))
1109 sprintf(buf, "%lu MB", n >> 20);
1110 else
1111 sprintf(buf, "%lu KB", n >> 10);
1112 return buf;
1115 static void __init report_hugepages(void)
1117 struct hstate *h;
1119 for_each_hstate(h) {
1120 char buf[32];
1121 printk(KERN_INFO "HugeTLB registered %s page size, "
1122 "pre-allocated %ld pages\n",
1123 memfmt(buf, huge_page_size(h)),
1124 h->free_huge_pages);
1128 #ifdef CONFIG_HIGHMEM
1129 static void try_to_free_low(struct hstate *h, unsigned long count)
1131 int i;
1133 if (h->order >= MAX_ORDER)
1134 return;
1136 for (i = 0; i < MAX_NUMNODES; ++i) {
1137 struct page *page, *next;
1138 struct list_head *freel = &h->hugepage_freelists[i];
1139 list_for_each_entry_safe(page, next, freel, lru) {
1140 if (count >= h->nr_huge_pages)
1141 return;
1142 if (PageHighMem(page))
1143 continue;
1144 list_del(&page->lru);
1145 update_and_free_page(h, page);
1146 h->free_huge_pages--;
1147 h->free_huge_pages_node[page_to_nid(page)]--;
1151 #else
1152 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1155 #endif
1158 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1159 * balanced by operating on them in a round-robin fashion.
1160 * Returns 1 if an adjustment was made.
1162 static int adjust_pool_surplus(struct hstate *h, int delta)
1164 int start_nid, next_nid;
1165 int ret = 0;
1167 VM_BUG_ON(delta != -1 && delta != 1);
1169 if (delta < 0)
1170 start_nid = h->next_nid_to_alloc;
1171 else
1172 start_nid = h->next_nid_to_free;
1173 next_nid = start_nid;
1175 do {
1176 int nid = next_nid;
1177 if (delta < 0) {
1178 next_nid = hstate_next_node_to_alloc(h);
1180 * To shrink on this node, there must be a surplus page
1182 if (!h->surplus_huge_pages_node[nid])
1183 continue;
1185 if (delta > 0) {
1186 next_nid = hstate_next_node_to_free(h);
1188 * Surplus cannot exceed the total number of pages
1190 if (h->surplus_huge_pages_node[nid] >=
1191 h->nr_huge_pages_node[nid])
1192 continue;
1195 h->surplus_huge_pages += delta;
1196 h->surplus_huge_pages_node[nid] += delta;
1197 ret = 1;
1198 break;
1199 } while (next_nid != start_nid);
1201 return ret;
1204 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1205 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1207 unsigned long min_count, ret;
1209 if (h->order >= MAX_ORDER)
1210 return h->max_huge_pages;
1213 * Increase the pool size
1214 * First take pages out of surplus state. Then make up the
1215 * remaining difference by allocating fresh huge pages.
1217 * We might race with alloc_buddy_huge_page() here and be unable
1218 * to convert a surplus huge page to a normal huge page. That is
1219 * not critical, though, it just means the overall size of the
1220 * pool might be one hugepage larger than it needs to be, but
1221 * within all the constraints specified by the sysctls.
1223 spin_lock(&hugetlb_lock);
1224 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1225 if (!adjust_pool_surplus(h, -1))
1226 break;
1229 while (count > persistent_huge_pages(h)) {
1231 * If this allocation races such that we no longer need the
1232 * page, free_huge_page will handle it by freeing the page
1233 * and reducing the surplus.
1235 spin_unlock(&hugetlb_lock);
1236 ret = alloc_fresh_huge_page(h);
1237 spin_lock(&hugetlb_lock);
1238 if (!ret)
1239 goto out;
1244 * Decrease the pool size
1245 * First return free pages to the buddy allocator (being careful
1246 * to keep enough around to satisfy reservations). Then place
1247 * pages into surplus state as needed so the pool will shrink
1248 * to the desired size as pages become free.
1250 * By placing pages into the surplus state independent of the
1251 * overcommit value, we are allowing the surplus pool size to
1252 * exceed overcommit. There are few sane options here. Since
1253 * alloc_buddy_huge_page() is checking the global counter,
1254 * though, we'll note that we're not allowed to exceed surplus
1255 * and won't grow the pool anywhere else. Not until one of the
1256 * sysctls are changed, or the surplus pages go out of use.
1258 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1259 min_count = max(count, min_count);
1260 try_to_free_low(h, min_count);
1261 while (min_count < persistent_huge_pages(h)) {
1262 if (!free_pool_huge_page(h, 0))
1263 break;
1265 while (count < persistent_huge_pages(h)) {
1266 if (!adjust_pool_surplus(h, 1))
1267 break;
1269 out:
1270 ret = persistent_huge_pages(h);
1271 spin_unlock(&hugetlb_lock);
1272 return ret;
1275 #define HSTATE_ATTR_RO(_name) \
1276 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1278 #define HSTATE_ATTR(_name) \
1279 static struct kobj_attribute _name##_attr = \
1280 __ATTR(_name, 0644, _name##_show, _name##_store)
1282 static struct kobject *hugepages_kobj;
1283 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1285 static struct hstate *kobj_to_hstate(struct kobject *kobj)
1287 int i;
1288 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1289 if (hstate_kobjs[i] == kobj)
1290 return &hstates[i];
1291 BUG();
1292 return NULL;
1295 static ssize_t nr_hugepages_show(struct kobject *kobj,
1296 struct kobj_attribute *attr, char *buf)
1298 struct hstate *h = kobj_to_hstate(kobj);
1299 return sprintf(buf, "%lu\n", h->nr_huge_pages);
1301 static ssize_t nr_hugepages_store(struct kobject *kobj,
1302 struct kobj_attribute *attr, const char *buf, size_t count)
1304 int err;
1305 unsigned long input;
1306 struct hstate *h = kobj_to_hstate(kobj);
1308 err = strict_strtoul(buf, 10, &input);
1309 if (err)
1310 return 0;
1312 h->max_huge_pages = set_max_huge_pages(h, input);
1314 return count;
1316 HSTATE_ATTR(nr_hugepages);
1318 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1319 struct kobj_attribute *attr, char *buf)
1321 struct hstate *h = kobj_to_hstate(kobj);
1322 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1324 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1325 struct kobj_attribute *attr, const char *buf, size_t count)
1327 int err;
1328 unsigned long input;
1329 struct hstate *h = kobj_to_hstate(kobj);
1331 err = strict_strtoul(buf, 10, &input);
1332 if (err)
1333 return 0;
1335 spin_lock(&hugetlb_lock);
1336 h->nr_overcommit_huge_pages = input;
1337 spin_unlock(&hugetlb_lock);
1339 return count;
1341 HSTATE_ATTR(nr_overcommit_hugepages);
1343 static ssize_t free_hugepages_show(struct kobject *kobj,
1344 struct kobj_attribute *attr, char *buf)
1346 struct hstate *h = kobj_to_hstate(kobj);
1347 return sprintf(buf, "%lu\n", h->free_huge_pages);
1349 HSTATE_ATTR_RO(free_hugepages);
1351 static ssize_t resv_hugepages_show(struct kobject *kobj,
1352 struct kobj_attribute *attr, char *buf)
1354 struct hstate *h = kobj_to_hstate(kobj);
1355 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1357 HSTATE_ATTR_RO(resv_hugepages);
1359 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1360 struct kobj_attribute *attr, char *buf)
1362 struct hstate *h = kobj_to_hstate(kobj);
1363 return sprintf(buf, "%lu\n", h->surplus_huge_pages);
1365 HSTATE_ATTR_RO(surplus_hugepages);
1367 static struct attribute *hstate_attrs[] = {
1368 &nr_hugepages_attr.attr,
1369 &nr_overcommit_hugepages_attr.attr,
1370 &free_hugepages_attr.attr,
1371 &resv_hugepages_attr.attr,
1372 &surplus_hugepages_attr.attr,
1373 NULL,
1376 static struct attribute_group hstate_attr_group = {
1377 .attrs = hstate_attrs,
1380 static int __init hugetlb_sysfs_add_hstate(struct hstate *h)
1382 int retval;
1384 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name,
1385 hugepages_kobj);
1386 if (!hstate_kobjs[h - hstates])
1387 return -ENOMEM;
1389 retval = sysfs_create_group(hstate_kobjs[h - hstates],
1390 &hstate_attr_group);
1391 if (retval)
1392 kobject_put(hstate_kobjs[h - hstates]);
1394 return retval;
1397 static void __init hugetlb_sysfs_init(void)
1399 struct hstate *h;
1400 int err;
1402 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1403 if (!hugepages_kobj)
1404 return;
1406 for_each_hstate(h) {
1407 err = hugetlb_sysfs_add_hstate(h);
1408 if (err)
1409 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1410 h->name);
1414 static void __exit hugetlb_exit(void)
1416 struct hstate *h;
1418 for_each_hstate(h) {
1419 kobject_put(hstate_kobjs[h - hstates]);
1422 kobject_put(hugepages_kobj);
1424 module_exit(hugetlb_exit);
1426 static int __init hugetlb_init(void)
1428 /* Some platform decide whether they support huge pages at boot
1429 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1430 * there is no such support
1432 if (HPAGE_SHIFT == 0)
1433 return 0;
1435 if (!size_to_hstate(default_hstate_size)) {
1436 default_hstate_size = HPAGE_SIZE;
1437 if (!size_to_hstate(default_hstate_size))
1438 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1440 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1441 if (default_hstate_max_huge_pages)
1442 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1444 hugetlb_init_hstates();
1446 gather_bootmem_prealloc();
1448 report_hugepages();
1450 hugetlb_sysfs_init();
1452 return 0;
1454 module_init(hugetlb_init);
1456 /* Should be called on processing a hugepagesz=... option */
1457 void __init hugetlb_add_hstate(unsigned order)
1459 struct hstate *h;
1460 unsigned long i;
1462 if (size_to_hstate(PAGE_SIZE << order)) {
1463 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1464 return;
1466 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1467 BUG_ON(order == 0);
1468 h = &hstates[max_hstate++];
1469 h->order = order;
1470 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1471 h->nr_huge_pages = 0;
1472 h->free_huge_pages = 0;
1473 for (i = 0; i < MAX_NUMNODES; ++i)
1474 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1475 h->next_nid_to_alloc = first_node(node_online_map);
1476 h->next_nid_to_free = first_node(node_online_map);
1477 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1478 huge_page_size(h)/1024);
1480 parsed_hstate = h;
1483 static int __init hugetlb_nrpages_setup(char *s)
1485 unsigned long *mhp;
1486 static unsigned long *last_mhp;
1489 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1490 * so this hugepages= parameter goes to the "default hstate".
1492 if (!max_hstate)
1493 mhp = &default_hstate_max_huge_pages;
1494 else
1495 mhp = &parsed_hstate->max_huge_pages;
1497 if (mhp == last_mhp) {
1498 printk(KERN_WARNING "hugepages= specified twice without "
1499 "interleaving hugepagesz=, ignoring\n");
1500 return 1;
1503 if (sscanf(s, "%lu", mhp) <= 0)
1504 *mhp = 0;
1507 * Global state is always initialized later in hugetlb_init.
1508 * But we need to allocate >= MAX_ORDER hstates here early to still
1509 * use the bootmem allocator.
1511 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1512 hugetlb_hstate_alloc_pages(parsed_hstate);
1514 last_mhp = mhp;
1516 return 1;
1518 __setup("hugepages=", hugetlb_nrpages_setup);
1520 static int __init hugetlb_default_setup(char *s)
1522 default_hstate_size = memparse(s, &s);
1523 return 1;
1525 __setup("default_hugepagesz=", hugetlb_default_setup);
1527 static unsigned int cpuset_mems_nr(unsigned int *array)
1529 int node;
1530 unsigned int nr = 0;
1532 for_each_node_mask(node, cpuset_current_mems_allowed)
1533 nr += array[node];
1535 return nr;
1538 #ifdef CONFIG_SYSCTL
1539 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1540 void __user *buffer,
1541 size_t *length, loff_t *ppos)
1543 struct hstate *h = &default_hstate;
1544 unsigned long tmp;
1546 if (!write)
1547 tmp = h->max_huge_pages;
1549 table->data = &tmp;
1550 table->maxlen = sizeof(unsigned long);
1551 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1553 if (write)
1554 h->max_huge_pages = set_max_huge_pages(h, tmp);
1556 return 0;
1559 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1560 void __user *buffer,
1561 size_t *length, loff_t *ppos)
1563 proc_dointvec(table, write, buffer, length, ppos);
1564 if (hugepages_treat_as_movable)
1565 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1566 else
1567 htlb_alloc_mask = GFP_HIGHUSER;
1568 return 0;
1571 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1572 void __user *buffer,
1573 size_t *length, loff_t *ppos)
1575 struct hstate *h = &default_hstate;
1576 unsigned long tmp;
1578 if (!write)
1579 tmp = h->nr_overcommit_huge_pages;
1581 table->data = &tmp;
1582 table->maxlen = sizeof(unsigned long);
1583 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1585 if (write) {
1586 spin_lock(&hugetlb_lock);
1587 h->nr_overcommit_huge_pages = tmp;
1588 spin_unlock(&hugetlb_lock);
1591 return 0;
1594 #endif /* CONFIG_SYSCTL */
1596 void hugetlb_report_meminfo(struct seq_file *m)
1598 struct hstate *h = &default_hstate;
1599 seq_printf(m,
1600 "HugePages_Total: %5lu\n"
1601 "HugePages_Free: %5lu\n"
1602 "HugePages_Rsvd: %5lu\n"
1603 "HugePages_Surp: %5lu\n"
1604 "Hugepagesize: %8lu kB\n",
1605 h->nr_huge_pages,
1606 h->free_huge_pages,
1607 h->resv_huge_pages,
1608 h->surplus_huge_pages,
1609 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1612 int hugetlb_report_node_meminfo(int nid, char *buf)
1614 struct hstate *h = &default_hstate;
1615 return sprintf(buf,
1616 "Node %d HugePages_Total: %5u\n"
1617 "Node %d HugePages_Free: %5u\n"
1618 "Node %d HugePages_Surp: %5u\n",
1619 nid, h->nr_huge_pages_node[nid],
1620 nid, h->free_huge_pages_node[nid],
1621 nid, h->surplus_huge_pages_node[nid]);
1624 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1625 unsigned long hugetlb_total_pages(void)
1627 struct hstate *h = &default_hstate;
1628 return h->nr_huge_pages * pages_per_huge_page(h);
1631 static int hugetlb_acct_memory(struct hstate *h, long delta)
1633 int ret = -ENOMEM;
1635 spin_lock(&hugetlb_lock);
1637 * When cpuset is configured, it breaks the strict hugetlb page
1638 * reservation as the accounting is done on a global variable. Such
1639 * reservation is completely rubbish in the presence of cpuset because
1640 * the reservation is not checked against page availability for the
1641 * current cpuset. Application can still potentially OOM'ed by kernel
1642 * with lack of free htlb page in cpuset that the task is in.
1643 * Attempt to enforce strict accounting with cpuset is almost
1644 * impossible (or too ugly) because cpuset is too fluid that
1645 * task or memory node can be dynamically moved between cpusets.
1647 * The change of semantics for shared hugetlb mapping with cpuset is
1648 * undesirable. However, in order to preserve some of the semantics,
1649 * we fall back to check against current free page availability as
1650 * a best attempt and hopefully to minimize the impact of changing
1651 * semantics that cpuset has.
1653 if (delta > 0) {
1654 if (gather_surplus_pages(h, delta) < 0)
1655 goto out;
1657 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1658 return_unused_surplus_pages(h, delta);
1659 goto out;
1663 ret = 0;
1664 if (delta < 0)
1665 return_unused_surplus_pages(h, (unsigned long) -delta);
1667 out:
1668 spin_unlock(&hugetlb_lock);
1669 return ret;
1672 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1674 struct resv_map *reservations = vma_resv_map(vma);
1677 * This new VMA should share its siblings reservation map if present.
1678 * The VMA will only ever have a valid reservation map pointer where
1679 * it is being copied for another still existing VMA. As that VMA
1680 * has a reference to the reservation map it cannot dissappear until
1681 * after this open call completes. It is therefore safe to take a
1682 * new reference here without additional locking.
1684 if (reservations)
1685 kref_get(&reservations->refs);
1688 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1690 struct hstate *h = hstate_vma(vma);
1691 struct resv_map *reservations = vma_resv_map(vma);
1692 unsigned long reserve;
1693 unsigned long start;
1694 unsigned long end;
1696 if (reservations) {
1697 start = vma_hugecache_offset(h, vma, vma->vm_start);
1698 end = vma_hugecache_offset(h, vma, vma->vm_end);
1700 reserve = (end - start) -
1701 region_count(&reservations->regions, start, end);
1703 kref_put(&reservations->refs, resv_map_release);
1705 if (reserve) {
1706 hugetlb_acct_memory(h, -reserve);
1707 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
1713 * We cannot handle pagefaults against hugetlb pages at all. They cause
1714 * handle_mm_fault() to try to instantiate regular-sized pages in the
1715 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1716 * this far.
1718 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1720 BUG();
1721 return 0;
1724 const struct vm_operations_struct hugetlb_vm_ops = {
1725 .fault = hugetlb_vm_op_fault,
1726 .open = hugetlb_vm_op_open,
1727 .close = hugetlb_vm_op_close,
1730 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1731 int writable)
1733 pte_t entry;
1735 if (writable) {
1736 entry =
1737 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1738 } else {
1739 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1741 entry = pte_mkyoung(entry);
1742 entry = pte_mkhuge(entry);
1744 return entry;
1747 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1748 unsigned long address, pte_t *ptep)
1750 pte_t entry;
1752 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1753 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1754 update_mmu_cache(vma, address, entry);
1759 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1760 struct vm_area_struct *vma)
1762 pte_t *src_pte, *dst_pte, entry;
1763 struct page *ptepage;
1764 unsigned long addr;
1765 int cow;
1766 struct hstate *h = hstate_vma(vma);
1767 unsigned long sz = huge_page_size(h);
1769 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1771 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1772 src_pte = huge_pte_offset(src, addr);
1773 if (!src_pte)
1774 continue;
1775 dst_pte = huge_pte_alloc(dst, addr, sz);
1776 if (!dst_pte)
1777 goto nomem;
1779 /* If the pagetables are shared don't copy or take references */
1780 if (dst_pte == src_pte)
1781 continue;
1783 spin_lock(&dst->page_table_lock);
1784 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1785 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1786 if (cow)
1787 huge_ptep_set_wrprotect(src, addr, src_pte);
1788 entry = huge_ptep_get(src_pte);
1789 ptepage = pte_page(entry);
1790 get_page(ptepage);
1791 set_huge_pte_at(dst, addr, dst_pte, entry);
1793 spin_unlock(&src->page_table_lock);
1794 spin_unlock(&dst->page_table_lock);
1796 return 0;
1798 nomem:
1799 return -ENOMEM;
1802 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1803 unsigned long end, struct page *ref_page)
1805 struct mm_struct *mm = vma->vm_mm;
1806 unsigned long address;
1807 pte_t *ptep;
1808 pte_t pte;
1809 struct page *page;
1810 struct page *tmp;
1811 struct hstate *h = hstate_vma(vma);
1812 unsigned long sz = huge_page_size(h);
1815 * A page gathering list, protected by per file i_mmap_lock. The
1816 * lock is used to avoid list corruption from multiple unmapping
1817 * of the same page since we are using page->lru.
1819 LIST_HEAD(page_list);
1821 WARN_ON(!is_vm_hugetlb_page(vma));
1822 BUG_ON(start & ~huge_page_mask(h));
1823 BUG_ON(end & ~huge_page_mask(h));
1825 mmu_notifier_invalidate_range_start(mm, start, end);
1826 spin_lock(&mm->page_table_lock);
1827 for (address = start; address < end; address += sz) {
1828 ptep = huge_pte_offset(mm, address);
1829 if (!ptep)
1830 continue;
1832 if (huge_pmd_unshare(mm, &address, ptep))
1833 continue;
1836 * If a reference page is supplied, it is because a specific
1837 * page is being unmapped, not a range. Ensure the page we
1838 * are about to unmap is the actual page of interest.
1840 if (ref_page) {
1841 pte = huge_ptep_get(ptep);
1842 if (huge_pte_none(pte))
1843 continue;
1844 page = pte_page(pte);
1845 if (page != ref_page)
1846 continue;
1849 * Mark the VMA as having unmapped its page so that
1850 * future faults in this VMA will fail rather than
1851 * looking like data was lost
1853 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1856 pte = huge_ptep_get_and_clear(mm, address, ptep);
1857 if (huge_pte_none(pte))
1858 continue;
1860 page = pte_page(pte);
1861 if (pte_dirty(pte))
1862 set_page_dirty(page);
1863 list_add(&page->lru, &page_list);
1865 spin_unlock(&mm->page_table_lock);
1866 flush_tlb_range(vma, start, end);
1867 mmu_notifier_invalidate_range_end(mm, start, end);
1868 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1869 list_del(&page->lru);
1870 put_page(page);
1874 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1875 unsigned long end, struct page *ref_page)
1877 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1878 __unmap_hugepage_range(vma, start, end, ref_page);
1879 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1883 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1884 * mappping it owns the reserve page for. The intention is to unmap the page
1885 * from other VMAs and let the children be SIGKILLed if they are faulting the
1886 * same region.
1888 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
1889 struct page *page, unsigned long address)
1891 struct hstate *h = hstate_vma(vma);
1892 struct vm_area_struct *iter_vma;
1893 struct address_space *mapping;
1894 struct prio_tree_iter iter;
1895 pgoff_t pgoff;
1898 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1899 * from page cache lookup which is in HPAGE_SIZE units.
1901 address = address & huge_page_mask(h);
1902 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1903 + (vma->vm_pgoff >> PAGE_SHIFT);
1904 mapping = (struct address_space *)page_private(page);
1906 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1907 /* Do not unmap the current VMA */
1908 if (iter_vma == vma)
1909 continue;
1912 * Unmap the page from other VMAs without their own reserves.
1913 * They get marked to be SIGKILLed if they fault in these
1914 * areas. This is because a future no-page fault on this VMA
1915 * could insert a zeroed page instead of the data existing
1916 * from the time of fork. This would look like data corruption
1918 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1919 unmap_hugepage_range(iter_vma,
1920 address, address + huge_page_size(h),
1921 page);
1924 return 1;
1927 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1928 unsigned long address, pte_t *ptep, pte_t pte,
1929 struct page *pagecache_page)
1931 struct hstate *h = hstate_vma(vma);
1932 struct page *old_page, *new_page;
1933 int avoidcopy;
1934 int outside_reserve = 0;
1936 old_page = pte_page(pte);
1938 retry_avoidcopy:
1939 /* If no-one else is actually using this page, avoid the copy
1940 * and just make the page writable */
1941 avoidcopy = (page_count(old_page) == 1);
1942 if (avoidcopy) {
1943 set_huge_ptep_writable(vma, address, ptep);
1944 return 0;
1948 * If the process that created a MAP_PRIVATE mapping is about to
1949 * perform a COW due to a shared page count, attempt to satisfy
1950 * the allocation without using the existing reserves. The pagecache
1951 * page is used to determine if the reserve at this address was
1952 * consumed or not. If reserves were used, a partial faulted mapping
1953 * at the time of fork() could consume its reserves on COW instead
1954 * of the full address range.
1956 if (!(vma->vm_flags & VM_MAYSHARE) &&
1957 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1958 old_page != pagecache_page)
1959 outside_reserve = 1;
1961 page_cache_get(old_page);
1962 new_page = alloc_huge_page(vma, address, outside_reserve);
1964 if (IS_ERR(new_page)) {
1965 page_cache_release(old_page);
1968 * If a process owning a MAP_PRIVATE mapping fails to COW,
1969 * it is due to references held by a child and an insufficient
1970 * huge page pool. To guarantee the original mappers
1971 * reliability, unmap the page from child processes. The child
1972 * may get SIGKILLed if it later faults.
1974 if (outside_reserve) {
1975 BUG_ON(huge_pte_none(pte));
1976 if (unmap_ref_private(mm, vma, old_page, address)) {
1977 BUG_ON(page_count(old_page) != 1);
1978 BUG_ON(huge_pte_none(pte));
1979 goto retry_avoidcopy;
1981 WARN_ON_ONCE(1);
1984 return -PTR_ERR(new_page);
1987 spin_unlock(&mm->page_table_lock);
1988 copy_huge_page(new_page, old_page, address, vma);
1989 __SetPageUptodate(new_page);
1990 spin_lock(&mm->page_table_lock);
1992 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
1993 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
1994 /* Break COW */
1995 huge_ptep_clear_flush(vma, address, ptep);
1996 set_huge_pte_at(mm, address, ptep,
1997 make_huge_pte(vma, new_page, 1));
1998 /* Make the old page be freed below */
1999 new_page = old_page;
2001 page_cache_release(new_page);
2002 page_cache_release(old_page);
2003 return 0;
2006 /* Return the pagecache page at a given address within a VMA */
2007 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2008 struct vm_area_struct *vma, unsigned long address)
2010 struct address_space *mapping;
2011 pgoff_t idx;
2013 mapping = vma->vm_file->f_mapping;
2014 idx = vma_hugecache_offset(h, vma, address);
2016 return find_lock_page(mapping, idx);
2020 * Return whether there is a pagecache page to back given address within VMA.
2021 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2023 static bool hugetlbfs_pagecache_present(struct hstate *h,
2024 struct vm_area_struct *vma, unsigned long address)
2026 struct address_space *mapping;
2027 pgoff_t idx;
2028 struct page *page;
2030 mapping = vma->vm_file->f_mapping;
2031 idx = vma_hugecache_offset(h, vma, address);
2033 page = find_get_page(mapping, idx);
2034 if (page)
2035 put_page(page);
2036 return page != NULL;
2039 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2040 unsigned long address, pte_t *ptep, unsigned int flags)
2042 struct hstate *h = hstate_vma(vma);
2043 int ret = VM_FAULT_SIGBUS;
2044 pgoff_t idx;
2045 unsigned long size;
2046 struct page *page;
2047 struct address_space *mapping;
2048 pte_t new_pte;
2051 * Currently, we are forced to kill the process in the event the
2052 * original mapper has unmapped pages from the child due to a failed
2053 * COW. Warn that such a situation has occured as it may not be obvious
2055 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2056 printk(KERN_WARNING
2057 "PID %d killed due to inadequate hugepage pool\n",
2058 current->pid);
2059 return ret;
2062 mapping = vma->vm_file->f_mapping;
2063 idx = vma_hugecache_offset(h, vma, address);
2066 * Use page lock to guard against racing truncation
2067 * before we get page_table_lock.
2069 retry:
2070 page = find_lock_page(mapping, idx);
2071 if (!page) {
2072 size = i_size_read(mapping->host) >> huge_page_shift(h);
2073 if (idx >= size)
2074 goto out;
2075 page = alloc_huge_page(vma, address, 0);
2076 if (IS_ERR(page)) {
2077 ret = -PTR_ERR(page);
2078 goto out;
2080 clear_huge_page(page, address, huge_page_size(h));
2081 __SetPageUptodate(page);
2083 if (vma->vm_flags & VM_MAYSHARE) {
2084 int err;
2085 struct inode *inode = mapping->host;
2087 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2088 if (err) {
2089 put_page(page);
2090 if (err == -EEXIST)
2091 goto retry;
2092 goto out;
2095 spin_lock(&inode->i_lock);
2096 inode->i_blocks += blocks_per_huge_page(h);
2097 spin_unlock(&inode->i_lock);
2098 } else
2099 lock_page(page);
2103 * If we are going to COW a private mapping later, we examine the
2104 * pending reservations for this page now. This will ensure that
2105 * any allocations necessary to record that reservation occur outside
2106 * the spinlock.
2108 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2109 if (vma_needs_reservation(h, vma, address) < 0) {
2110 ret = VM_FAULT_OOM;
2111 goto backout_unlocked;
2114 spin_lock(&mm->page_table_lock);
2115 size = i_size_read(mapping->host) >> huge_page_shift(h);
2116 if (idx >= size)
2117 goto backout;
2119 ret = 0;
2120 if (!huge_pte_none(huge_ptep_get(ptep)))
2121 goto backout;
2123 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2124 && (vma->vm_flags & VM_SHARED)));
2125 set_huge_pte_at(mm, address, ptep, new_pte);
2127 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2128 /* Optimization, do the COW without a second fault */
2129 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2132 spin_unlock(&mm->page_table_lock);
2133 unlock_page(page);
2134 out:
2135 return ret;
2137 backout:
2138 spin_unlock(&mm->page_table_lock);
2139 backout_unlocked:
2140 unlock_page(page);
2141 put_page(page);
2142 goto out;
2145 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2146 unsigned long address, unsigned int flags)
2148 pte_t *ptep;
2149 pte_t entry;
2150 int ret;
2151 struct page *pagecache_page = NULL;
2152 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2153 struct hstate *h = hstate_vma(vma);
2155 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2156 if (!ptep)
2157 return VM_FAULT_OOM;
2160 * Serialize hugepage allocation and instantiation, so that we don't
2161 * get spurious allocation failures if two CPUs race to instantiate
2162 * the same page in the page cache.
2164 mutex_lock(&hugetlb_instantiation_mutex);
2165 entry = huge_ptep_get(ptep);
2166 if (huge_pte_none(entry)) {
2167 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2168 goto out_mutex;
2171 ret = 0;
2174 * If we are going to COW the mapping later, we examine the pending
2175 * reservations for this page now. This will ensure that any
2176 * allocations necessary to record that reservation occur outside the
2177 * spinlock. For private mappings, we also lookup the pagecache
2178 * page now as it is used to determine if a reservation has been
2179 * consumed.
2181 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2182 if (vma_needs_reservation(h, vma, address) < 0) {
2183 ret = VM_FAULT_OOM;
2184 goto out_mutex;
2187 if (!(vma->vm_flags & VM_MAYSHARE))
2188 pagecache_page = hugetlbfs_pagecache_page(h,
2189 vma, address);
2192 spin_lock(&mm->page_table_lock);
2193 /* Check for a racing update before calling hugetlb_cow */
2194 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2195 goto out_page_table_lock;
2198 if (flags & FAULT_FLAG_WRITE) {
2199 if (!pte_write(entry)) {
2200 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2201 pagecache_page);
2202 goto out_page_table_lock;
2204 entry = pte_mkdirty(entry);
2206 entry = pte_mkyoung(entry);
2207 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2208 flags & FAULT_FLAG_WRITE))
2209 update_mmu_cache(vma, address, entry);
2211 out_page_table_lock:
2212 spin_unlock(&mm->page_table_lock);
2214 if (pagecache_page) {
2215 unlock_page(pagecache_page);
2216 put_page(pagecache_page);
2219 out_mutex:
2220 mutex_unlock(&hugetlb_instantiation_mutex);
2222 return ret;
2225 /* Can be overriden by architectures */
2226 __attribute__((weak)) struct page *
2227 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2228 pud_t *pud, int write)
2230 BUG();
2231 return NULL;
2234 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2235 struct page **pages, struct vm_area_struct **vmas,
2236 unsigned long *position, int *length, int i,
2237 unsigned int flags)
2239 unsigned long pfn_offset;
2240 unsigned long vaddr = *position;
2241 int remainder = *length;
2242 struct hstate *h = hstate_vma(vma);
2244 spin_lock(&mm->page_table_lock);
2245 while (vaddr < vma->vm_end && remainder) {
2246 pte_t *pte;
2247 int absent;
2248 struct page *page;
2251 * Some archs (sparc64, sh*) have multiple pte_ts to
2252 * each hugepage. We have to make sure we get the
2253 * first, for the page indexing below to work.
2255 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2256 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2259 * When coredumping, it suits get_dump_page if we just return
2260 * an error where there's an empty slot with no huge pagecache
2261 * to back it. This way, we avoid allocating a hugepage, and
2262 * the sparse dumpfile avoids allocating disk blocks, but its
2263 * huge holes still show up with zeroes where they need to be.
2265 if (absent && (flags & FOLL_DUMP) &&
2266 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2267 remainder = 0;
2268 break;
2271 if (absent ||
2272 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2273 int ret;
2275 spin_unlock(&mm->page_table_lock);
2276 ret = hugetlb_fault(mm, vma, vaddr,
2277 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2278 spin_lock(&mm->page_table_lock);
2279 if (!(ret & VM_FAULT_ERROR))
2280 continue;
2282 remainder = 0;
2283 break;
2286 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2287 page = pte_page(huge_ptep_get(pte));
2288 same_page:
2289 if (pages) {
2290 pages[i] = mem_map_offset(page, pfn_offset);
2291 get_page(pages[i]);
2294 if (vmas)
2295 vmas[i] = vma;
2297 vaddr += PAGE_SIZE;
2298 ++pfn_offset;
2299 --remainder;
2300 ++i;
2301 if (vaddr < vma->vm_end && remainder &&
2302 pfn_offset < pages_per_huge_page(h)) {
2304 * We use pfn_offset to avoid touching the pageframes
2305 * of this compound page.
2307 goto same_page;
2310 spin_unlock(&mm->page_table_lock);
2311 *length = remainder;
2312 *position = vaddr;
2314 return i ? i : -EFAULT;
2317 void hugetlb_change_protection(struct vm_area_struct *vma,
2318 unsigned long address, unsigned long end, pgprot_t newprot)
2320 struct mm_struct *mm = vma->vm_mm;
2321 unsigned long start = address;
2322 pte_t *ptep;
2323 pte_t pte;
2324 struct hstate *h = hstate_vma(vma);
2326 BUG_ON(address >= end);
2327 flush_cache_range(vma, address, end);
2329 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2330 spin_lock(&mm->page_table_lock);
2331 for (; address < end; address += huge_page_size(h)) {
2332 ptep = huge_pte_offset(mm, address);
2333 if (!ptep)
2334 continue;
2335 if (huge_pmd_unshare(mm, &address, ptep))
2336 continue;
2337 if (!huge_pte_none(huge_ptep_get(ptep))) {
2338 pte = huge_ptep_get_and_clear(mm, address, ptep);
2339 pte = pte_mkhuge(pte_modify(pte, newprot));
2340 set_huge_pte_at(mm, address, ptep, pte);
2343 spin_unlock(&mm->page_table_lock);
2344 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2346 flush_tlb_range(vma, start, end);
2349 int hugetlb_reserve_pages(struct inode *inode,
2350 long from, long to,
2351 struct vm_area_struct *vma,
2352 int acctflag)
2354 long ret, chg;
2355 struct hstate *h = hstate_inode(inode);
2358 * Only apply hugepage reservation if asked. At fault time, an
2359 * attempt will be made for VM_NORESERVE to allocate a page
2360 * and filesystem quota without using reserves
2362 if (acctflag & VM_NORESERVE)
2363 return 0;
2366 * Shared mappings base their reservation on the number of pages that
2367 * are already allocated on behalf of the file. Private mappings need
2368 * to reserve the full area even if read-only as mprotect() may be
2369 * called to make the mapping read-write. Assume !vma is a shm mapping
2371 if (!vma || vma->vm_flags & VM_MAYSHARE)
2372 chg = region_chg(&inode->i_mapping->private_list, from, to);
2373 else {
2374 struct resv_map *resv_map = resv_map_alloc();
2375 if (!resv_map)
2376 return -ENOMEM;
2378 chg = to - from;
2380 set_vma_resv_map(vma, resv_map);
2381 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2384 if (chg < 0)
2385 return chg;
2387 /* There must be enough filesystem quota for the mapping */
2388 if (hugetlb_get_quota(inode->i_mapping, chg))
2389 return -ENOSPC;
2392 * Check enough hugepages are available for the reservation.
2393 * Hand back the quota if there are not
2395 ret = hugetlb_acct_memory(h, chg);
2396 if (ret < 0) {
2397 hugetlb_put_quota(inode->i_mapping, chg);
2398 return ret;
2402 * Account for the reservations made. Shared mappings record regions
2403 * that have reservations as they are shared by multiple VMAs.
2404 * When the last VMA disappears, the region map says how much
2405 * the reservation was and the page cache tells how much of
2406 * the reservation was consumed. Private mappings are per-VMA and
2407 * only the consumed reservations are tracked. When the VMA
2408 * disappears, the original reservation is the VMA size and the
2409 * consumed reservations are stored in the map. Hence, nothing
2410 * else has to be done for private mappings here
2412 if (!vma || vma->vm_flags & VM_MAYSHARE)
2413 region_add(&inode->i_mapping->private_list, from, to);
2414 return 0;
2417 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2419 struct hstate *h = hstate_inode(inode);
2420 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2422 spin_lock(&inode->i_lock);
2423 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2424 spin_unlock(&inode->i_lock);
2426 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2427 hugetlb_acct_memory(h, -(chg - freed));