ext4: Remove automatic enabling of the HUGE_FILE feature flag
[linux-2.6/mini2440.git] / mm / hugetlb.c
blob38633864a93e874009d9e6aa00619cf7471b0d9e
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/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
21 #include <asm/page.h>
22 #include <asm/pgtable.h>
23 #include <asm/io.h>
25 #include <linux/hugetlb.h>
26 #include "internal.h"
28 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
29 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
30 unsigned long hugepages_treat_as_movable;
32 static int max_hstate;
33 unsigned int default_hstate_idx;
34 struct hstate hstates[HUGE_MAX_HSTATE];
36 __initdata LIST_HEAD(huge_boot_pages);
38 /* for command line parsing */
39 static struct hstate * __initdata parsed_hstate;
40 static unsigned long __initdata default_hstate_max_huge_pages;
41 static unsigned long __initdata default_hstate_size;
43 #define for_each_hstate(h) \
44 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
47 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
49 static DEFINE_SPINLOCK(hugetlb_lock);
52 * Region tracking -- allows tracking of reservations and instantiated pages
53 * across the pages in a mapping.
55 * The region data structures are protected by a combination of the mmap_sem
56 * and the hugetlb_instantion_mutex. To access or modify a region the caller
57 * must either hold the mmap_sem for write, or the mmap_sem for read and
58 * the hugetlb_instantiation mutex:
60 * down_write(&mm->mmap_sem);
61 * or
62 * down_read(&mm->mmap_sem);
63 * mutex_lock(&hugetlb_instantiation_mutex);
65 struct file_region {
66 struct list_head link;
67 long from;
68 long to;
71 static long region_add(struct list_head *head, long f, long t)
73 struct file_region *rg, *nrg, *trg;
75 /* Locate the region we are either in or before. */
76 list_for_each_entry(rg, head, link)
77 if (f <= rg->to)
78 break;
80 /* Round our left edge to the current segment if it encloses us. */
81 if (f > rg->from)
82 f = rg->from;
84 /* Check for and consume any regions we now overlap with. */
85 nrg = rg;
86 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
87 if (&rg->link == head)
88 break;
89 if (rg->from > t)
90 break;
92 /* If this area reaches higher then extend our area to
93 * include it completely. If this is not the first area
94 * which we intend to reuse, free it. */
95 if (rg->to > t)
96 t = rg->to;
97 if (rg != nrg) {
98 list_del(&rg->link);
99 kfree(rg);
102 nrg->from = f;
103 nrg->to = t;
104 return 0;
107 static long region_chg(struct list_head *head, long f, long t)
109 struct file_region *rg, *nrg;
110 long chg = 0;
112 /* Locate the region we are before or in. */
113 list_for_each_entry(rg, head, link)
114 if (f <= rg->to)
115 break;
117 /* If we are below the current region then a new region is required.
118 * Subtle, allocate a new region at the position but make it zero
119 * size such that we can guarantee to record the reservation. */
120 if (&rg->link == head || t < rg->from) {
121 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
122 if (!nrg)
123 return -ENOMEM;
124 nrg->from = f;
125 nrg->to = f;
126 INIT_LIST_HEAD(&nrg->link);
127 list_add(&nrg->link, rg->link.prev);
129 return t - f;
132 /* Round our left edge to the current segment if it encloses us. */
133 if (f > rg->from)
134 f = rg->from;
135 chg = t - f;
137 /* Check for and consume any regions we now overlap with. */
138 list_for_each_entry(rg, rg->link.prev, link) {
139 if (&rg->link == head)
140 break;
141 if (rg->from > t)
142 return chg;
144 /* We overlap with this area, if it extends futher than
145 * us then we must extend ourselves. Account for its
146 * existing reservation. */
147 if (rg->to > t) {
148 chg += rg->to - t;
149 t = rg->to;
151 chg -= rg->to - rg->from;
153 return chg;
156 static long region_truncate(struct list_head *head, long end)
158 struct file_region *rg, *trg;
159 long chg = 0;
161 /* Locate the region we are either in or before. */
162 list_for_each_entry(rg, head, link)
163 if (end <= rg->to)
164 break;
165 if (&rg->link == head)
166 return 0;
168 /* If we are in the middle of a region then adjust it. */
169 if (end > rg->from) {
170 chg = rg->to - end;
171 rg->to = end;
172 rg = list_entry(rg->link.next, typeof(*rg), link);
175 /* Drop any remaining regions. */
176 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
177 if (&rg->link == head)
178 break;
179 chg += rg->to - rg->from;
180 list_del(&rg->link);
181 kfree(rg);
183 return chg;
186 static long region_count(struct list_head *head, long f, long t)
188 struct file_region *rg;
189 long chg = 0;
191 /* Locate each segment we overlap with, and count that overlap. */
192 list_for_each_entry(rg, head, link) {
193 int seg_from;
194 int seg_to;
196 if (rg->to <= f)
197 continue;
198 if (rg->from >= t)
199 break;
201 seg_from = max(rg->from, f);
202 seg_to = min(rg->to, t);
204 chg += seg_to - seg_from;
207 return chg;
211 * Convert the address within this vma to the page offset within
212 * the mapping, in pagecache page units; huge pages here.
214 static pgoff_t vma_hugecache_offset(struct hstate *h,
215 struct vm_area_struct *vma, unsigned long address)
217 return ((address - vma->vm_start) >> huge_page_shift(h)) +
218 (vma->vm_pgoff >> huge_page_order(h));
222 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
223 * bits of the reservation map pointer, which are always clear due to
224 * alignment.
226 #define HPAGE_RESV_OWNER (1UL << 0)
227 #define HPAGE_RESV_UNMAPPED (1UL << 1)
228 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
231 * These helpers are used to track how many pages are reserved for
232 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
233 * is guaranteed to have their future faults succeed.
235 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
236 * the reserve counters are updated with the hugetlb_lock held. It is safe
237 * to reset the VMA at fork() time as it is not in use yet and there is no
238 * chance of the global counters getting corrupted as a result of the values.
240 * The private mapping reservation is represented in a subtly different
241 * manner to a shared mapping. A shared mapping has a region map associated
242 * with the underlying file, this region map represents the backing file
243 * pages which have ever had a reservation assigned which this persists even
244 * after the page is instantiated. A private mapping has a region map
245 * associated with the original mmap which is attached to all VMAs which
246 * reference it, this region map represents those offsets which have consumed
247 * reservation ie. where pages have been instantiated.
249 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
251 return (unsigned long)vma->vm_private_data;
254 static void set_vma_private_data(struct vm_area_struct *vma,
255 unsigned long value)
257 vma->vm_private_data = (void *)value;
260 struct resv_map {
261 struct kref refs;
262 struct list_head regions;
265 struct resv_map *resv_map_alloc(void)
267 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
268 if (!resv_map)
269 return NULL;
271 kref_init(&resv_map->refs);
272 INIT_LIST_HEAD(&resv_map->regions);
274 return resv_map;
277 void resv_map_release(struct kref *ref)
279 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
281 /* Clear out any active regions before we release the map. */
282 region_truncate(&resv_map->regions, 0);
283 kfree(resv_map);
286 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
288 VM_BUG_ON(!is_vm_hugetlb_page(vma));
289 if (!(vma->vm_flags & VM_SHARED))
290 return (struct resv_map *)(get_vma_private_data(vma) &
291 ~HPAGE_RESV_MASK);
292 return 0;
295 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
297 VM_BUG_ON(!is_vm_hugetlb_page(vma));
298 VM_BUG_ON(vma->vm_flags & VM_SHARED);
300 set_vma_private_data(vma, (get_vma_private_data(vma) &
301 HPAGE_RESV_MASK) | (unsigned long)map);
304 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
306 VM_BUG_ON(!is_vm_hugetlb_page(vma));
307 VM_BUG_ON(vma->vm_flags & VM_SHARED);
309 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
312 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
314 VM_BUG_ON(!is_vm_hugetlb_page(vma));
316 return (get_vma_private_data(vma) & flag) != 0;
319 /* Decrement the reserved pages in the hugepage pool by one */
320 static void decrement_hugepage_resv_vma(struct hstate *h,
321 struct vm_area_struct *vma)
323 if (vma->vm_flags & VM_NORESERVE)
324 return;
326 if (vma->vm_flags & VM_SHARED) {
327 /* Shared mappings always use reserves */
328 h->resv_huge_pages--;
329 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
331 * Only the process that called mmap() has reserves for
332 * private mappings.
334 h->resv_huge_pages--;
338 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
339 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
341 VM_BUG_ON(!is_vm_hugetlb_page(vma));
342 if (!(vma->vm_flags & VM_SHARED))
343 vma->vm_private_data = (void *)0;
346 /* Returns true if the VMA has associated reserve pages */
347 static int vma_has_reserves(struct vm_area_struct *vma)
349 if (vma->vm_flags & VM_SHARED)
350 return 1;
351 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
352 return 1;
353 return 0;
356 static void clear_huge_page(struct page *page,
357 unsigned long addr, unsigned long sz)
359 int i;
361 might_sleep();
362 for (i = 0; i < sz/PAGE_SIZE; i++) {
363 cond_resched();
364 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
368 static void copy_huge_page(struct page *dst, struct page *src,
369 unsigned long addr, struct vm_area_struct *vma)
371 int i;
372 struct hstate *h = hstate_vma(vma);
374 might_sleep();
375 for (i = 0; i < pages_per_huge_page(h); i++) {
376 cond_resched();
377 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
381 static void enqueue_huge_page(struct hstate *h, struct page *page)
383 int nid = page_to_nid(page);
384 list_add(&page->lru, &h->hugepage_freelists[nid]);
385 h->free_huge_pages++;
386 h->free_huge_pages_node[nid]++;
389 static struct page *dequeue_huge_page(struct hstate *h)
391 int nid;
392 struct page *page = NULL;
394 for (nid = 0; nid < MAX_NUMNODES; ++nid) {
395 if (!list_empty(&h->hugepage_freelists[nid])) {
396 page = list_entry(h->hugepage_freelists[nid].next,
397 struct page, lru);
398 list_del(&page->lru);
399 h->free_huge_pages--;
400 h->free_huge_pages_node[nid]--;
401 break;
404 return page;
407 static struct page *dequeue_huge_page_vma(struct hstate *h,
408 struct vm_area_struct *vma,
409 unsigned long address, int avoid_reserve)
411 int nid;
412 struct page *page = NULL;
413 struct mempolicy *mpol;
414 nodemask_t *nodemask;
415 struct zonelist *zonelist = huge_zonelist(vma, address,
416 htlb_alloc_mask, &mpol, &nodemask);
417 struct zone *zone;
418 struct zoneref *z;
421 * A child process with MAP_PRIVATE mappings created by their parent
422 * have no page reserves. This check ensures that reservations are
423 * not "stolen". The child may still get SIGKILLed
425 if (!vma_has_reserves(vma) &&
426 h->free_huge_pages - h->resv_huge_pages == 0)
427 return NULL;
429 /* If reserves cannot be used, ensure enough pages are in the pool */
430 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
431 return NULL;
433 for_each_zone_zonelist_nodemask(zone, z, zonelist,
434 MAX_NR_ZONES - 1, nodemask) {
435 nid = zone_to_nid(zone);
436 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
437 !list_empty(&h->hugepage_freelists[nid])) {
438 page = list_entry(h->hugepage_freelists[nid].next,
439 struct page, lru);
440 list_del(&page->lru);
441 h->free_huge_pages--;
442 h->free_huge_pages_node[nid]--;
444 if (!avoid_reserve)
445 decrement_hugepage_resv_vma(h, vma);
447 break;
450 mpol_cond_put(mpol);
451 return page;
454 static void update_and_free_page(struct hstate *h, struct page *page)
456 int i;
458 h->nr_huge_pages--;
459 h->nr_huge_pages_node[page_to_nid(page)]--;
460 for (i = 0; i < pages_per_huge_page(h); i++) {
461 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
462 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
463 1 << PG_private | 1<< PG_writeback);
465 set_compound_page_dtor(page, NULL);
466 set_page_refcounted(page);
467 arch_release_hugepage(page);
468 __free_pages(page, huge_page_order(h));
471 struct hstate *size_to_hstate(unsigned long size)
473 struct hstate *h;
475 for_each_hstate(h) {
476 if (huge_page_size(h) == size)
477 return h;
479 return NULL;
482 static void free_huge_page(struct page *page)
485 * Can't pass hstate in here because it is called from the
486 * compound page destructor.
488 struct hstate *h = page_hstate(page);
489 int nid = page_to_nid(page);
490 struct address_space *mapping;
492 mapping = (struct address_space *) page_private(page);
493 set_page_private(page, 0);
494 BUG_ON(page_count(page));
495 INIT_LIST_HEAD(&page->lru);
497 spin_lock(&hugetlb_lock);
498 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
499 update_and_free_page(h, page);
500 h->surplus_huge_pages--;
501 h->surplus_huge_pages_node[nid]--;
502 } else {
503 enqueue_huge_page(h, page);
505 spin_unlock(&hugetlb_lock);
506 if (mapping)
507 hugetlb_put_quota(mapping, 1);
511 * Increment or decrement surplus_huge_pages. Keep node-specific counters
512 * balanced by operating on them in a round-robin fashion.
513 * Returns 1 if an adjustment was made.
515 static int adjust_pool_surplus(struct hstate *h, int delta)
517 static int prev_nid;
518 int nid = prev_nid;
519 int ret = 0;
521 VM_BUG_ON(delta != -1 && delta != 1);
522 do {
523 nid = next_node(nid, node_online_map);
524 if (nid == MAX_NUMNODES)
525 nid = first_node(node_online_map);
527 /* To shrink on this node, there must be a surplus page */
528 if (delta < 0 && !h->surplus_huge_pages_node[nid])
529 continue;
530 /* Surplus cannot exceed the total number of pages */
531 if (delta > 0 && h->surplus_huge_pages_node[nid] >=
532 h->nr_huge_pages_node[nid])
533 continue;
535 h->surplus_huge_pages += delta;
536 h->surplus_huge_pages_node[nid] += delta;
537 ret = 1;
538 break;
539 } while (nid != prev_nid);
541 prev_nid = nid;
542 return ret;
545 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
547 set_compound_page_dtor(page, free_huge_page);
548 spin_lock(&hugetlb_lock);
549 h->nr_huge_pages++;
550 h->nr_huge_pages_node[nid]++;
551 spin_unlock(&hugetlb_lock);
552 put_page(page); /* free it into the hugepage allocator */
555 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
557 struct page *page;
559 if (h->order >= MAX_ORDER)
560 return NULL;
562 page = alloc_pages_node(nid,
563 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
564 __GFP_REPEAT|__GFP_NOWARN,
565 huge_page_order(h));
566 if (page) {
567 if (arch_prepare_hugepage(page)) {
568 __free_pages(page, huge_page_order(h));
569 return NULL;
571 prep_new_huge_page(h, page, nid);
574 return page;
578 * Use a helper variable to find the next node and then
579 * copy it back to hugetlb_next_nid afterwards:
580 * otherwise there's a window in which a racer might
581 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
582 * But we don't need to use a spin_lock here: it really
583 * doesn't matter if occasionally a racer chooses the
584 * same nid as we do. Move nid forward in the mask even
585 * if we just successfully allocated a hugepage so that
586 * the next caller gets hugepages on the next node.
588 static int hstate_next_node(struct hstate *h)
590 int next_nid;
591 next_nid = next_node(h->hugetlb_next_nid, node_online_map);
592 if (next_nid == MAX_NUMNODES)
593 next_nid = first_node(node_online_map);
594 h->hugetlb_next_nid = next_nid;
595 return next_nid;
598 static int alloc_fresh_huge_page(struct hstate *h)
600 struct page *page;
601 int start_nid;
602 int next_nid;
603 int ret = 0;
605 start_nid = h->hugetlb_next_nid;
607 do {
608 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid);
609 if (page)
610 ret = 1;
611 next_nid = hstate_next_node(h);
612 } while (!page && h->hugetlb_next_nid != start_nid);
614 if (ret)
615 count_vm_event(HTLB_BUDDY_PGALLOC);
616 else
617 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
619 return ret;
622 static struct page *alloc_buddy_huge_page(struct hstate *h,
623 struct vm_area_struct *vma, unsigned long address)
625 struct page *page;
626 unsigned int nid;
628 if (h->order >= MAX_ORDER)
629 return NULL;
632 * Assume we will successfully allocate the surplus page to
633 * prevent racing processes from causing the surplus to exceed
634 * overcommit
636 * This however introduces a different race, where a process B
637 * tries to grow the static hugepage pool while alloc_pages() is
638 * called by process A. B will only examine the per-node
639 * counters in determining if surplus huge pages can be
640 * converted to normal huge pages in adjust_pool_surplus(). A
641 * won't be able to increment the per-node counter, until the
642 * lock is dropped by B, but B doesn't drop hugetlb_lock until
643 * no more huge pages can be converted from surplus to normal
644 * state (and doesn't try to convert again). Thus, we have a
645 * case where a surplus huge page exists, the pool is grown, and
646 * the surplus huge page still exists after, even though it
647 * should just have been converted to a normal huge page. This
648 * does not leak memory, though, as the hugepage will be freed
649 * once it is out of use. It also does not allow the counters to
650 * go out of whack in adjust_pool_surplus() as we don't modify
651 * the node values until we've gotten the hugepage and only the
652 * per-node value is checked there.
654 spin_lock(&hugetlb_lock);
655 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
656 spin_unlock(&hugetlb_lock);
657 return NULL;
658 } else {
659 h->nr_huge_pages++;
660 h->surplus_huge_pages++;
662 spin_unlock(&hugetlb_lock);
664 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
665 __GFP_REPEAT|__GFP_NOWARN,
666 huge_page_order(h));
668 if (page && arch_prepare_hugepage(page)) {
669 __free_pages(page, huge_page_order(h));
670 return NULL;
673 spin_lock(&hugetlb_lock);
674 if (page) {
676 * This page is now managed by the hugetlb allocator and has
677 * no users -- drop the buddy allocator's reference.
679 put_page_testzero(page);
680 VM_BUG_ON(page_count(page));
681 nid = page_to_nid(page);
682 set_compound_page_dtor(page, free_huge_page);
684 * We incremented the global counters already
686 h->nr_huge_pages_node[nid]++;
687 h->surplus_huge_pages_node[nid]++;
688 __count_vm_event(HTLB_BUDDY_PGALLOC);
689 } else {
690 h->nr_huge_pages--;
691 h->surplus_huge_pages--;
692 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
694 spin_unlock(&hugetlb_lock);
696 return page;
700 * Increase the hugetlb pool such that it can accomodate a reservation
701 * of size 'delta'.
703 static int gather_surplus_pages(struct hstate *h, int delta)
705 struct list_head surplus_list;
706 struct page *page, *tmp;
707 int ret, i;
708 int needed, allocated;
710 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
711 if (needed <= 0) {
712 h->resv_huge_pages += delta;
713 return 0;
716 allocated = 0;
717 INIT_LIST_HEAD(&surplus_list);
719 ret = -ENOMEM;
720 retry:
721 spin_unlock(&hugetlb_lock);
722 for (i = 0; i < needed; i++) {
723 page = alloc_buddy_huge_page(h, NULL, 0);
724 if (!page) {
726 * We were not able to allocate enough pages to
727 * satisfy the entire reservation so we free what
728 * we've allocated so far.
730 spin_lock(&hugetlb_lock);
731 needed = 0;
732 goto free;
735 list_add(&page->lru, &surplus_list);
737 allocated += needed;
740 * After retaking hugetlb_lock, we need to recalculate 'needed'
741 * because either resv_huge_pages or free_huge_pages may have changed.
743 spin_lock(&hugetlb_lock);
744 needed = (h->resv_huge_pages + delta) -
745 (h->free_huge_pages + allocated);
746 if (needed > 0)
747 goto retry;
750 * The surplus_list now contains _at_least_ the number of extra pages
751 * needed to accomodate the reservation. Add the appropriate number
752 * of pages to the hugetlb pool and free the extras back to the buddy
753 * allocator. Commit the entire reservation here to prevent another
754 * process from stealing the pages as they are added to the pool but
755 * before they are reserved.
757 needed += allocated;
758 h->resv_huge_pages += delta;
759 ret = 0;
760 free:
761 /* Free the needed pages to the hugetlb pool */
762 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
763 if ((--needed) < 0)
764 break;
765 list_del(&page->lru);
766 enqueue_huge_page(h, page);
769 /* Free unnecessary surplus pages to the buddy allocator */
770 if (!list_empty(&surplus_list)) {
771 spin_unlock(&hugetlb_lock);
772 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
773 list_del(&page->lru);
775 * The page has a reference count of zero already, so
776 * call free_huge_page directly instead of using
777 * put_page. This must be done with hugetlb_lock
778 * unlocked which is safe because free_huge_page takes
779 * hugetlb_lock before deciding how to free the page.
781 free_huge_page(page);
783 spin_lock(&hugetlb_lock);
786 return ret;
790 * When releasing a hugetlb pool reservation, any surplus pages that were
791 * allocated to satisfy the reservation must be explicitly freed if they were
792 * never used.
794 static void return_unused_surplus_pages(struct hstate *h,
795 unsigned long unused_resv_pages)
797 static int nid = -1;
798 struct page *page;
799 unsigned long nr_pages;
802 * We want to release as many surplus pages as possible, spread
803 * evenly across all nodes. Iterate across all nodes until we
804 * can no longer free unreserved surplus pages. This occurs when
805 * the nodes with surplus pages have no free pages.
807 unsigned long remaining_iterations = num_online_nodes();
809 /* Uncommit the reservation */
810 h->resv_huge_pages -= unused_resv_pages;
812 /* Cannot return gigantic pages currently */
813 if (h->order >= MAX_ORDER)
814 return;
816 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
818 while (remaining_iterations-- && nr_pages) {
819 nid = next_node(nid, node_online_map);
820 if (nid == MAX_NUMNODES)
821 nid = first_node(node_online_map);
823 if (!h->surplus_huge_pages_node[nid])
824 continue;
826 if (!list_empty(&h->hugepage_freelists[nid])) {
827 page = list_entry(h->hugepage_freelists[nid].next,
828 struct page, lru);
829 list_del(&page->lru);
830 update_and_free_page(h, page);
831 h->free_huge_pages--;
832 h->free_huge_pages_node[nid]--;
833 h->surplus_huge_pages--;
834 h->surplus_huge_pages_node[nid]--;
835 nr_pages--;
836 remaining_iterations = num_online_nodes();
842 * Determine if the huge page at addr within the vma has an associated
843 * reservation. Where it does not we will need to logically increase
844 * reservation and actually increase quota before an allocation can occur.
845 * Where any new reservation would be required the reservation change is
846 * prepared, but not committed. Once the page has been quota'd allocated
847 * an instantiated the change should be committed via vma_commit_reservation.
848 * No action is required on failure.
850 static int vma_needs_reservation(struct hstate *h,
851 struct vm_area_struct *vma, unsigned long addr)
853 struct address_space *mapping = vma->vm_file->f_mapping;
854 struct inode *inode = mapping->host;
856 if (vma->vm_flags & VM_SHARED) {
857 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
858 return region_chg(&inode->i_mapping->private_list,
859 idx, idx + 1);
861 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
862 return 1;
864 } else {
865 int err;
866 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
867 struct resv_map *reservations = vma_resv_map(vma);
869 err = region_chg(&reservations->regions, idx, idx + 1);
870 if (err < 0)
871 return err;
872 return 0;
875 static void vma_commit_reservation(struct hstate *h,
876 struct vm_area_struct *vma, unsigned long addr)
878 struct address_space *mapping = vma->vm_file->f_mapping;
879 struct inode *inode = mapping->host;
881 if (vma->vm_flags & VM_SHARED) {
882 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
883 region_add(&inode->i_mapping->private_list, idx, idx + 1);
885 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
886 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
887 struct resv_map *reservations = vma_resv_map(vma);
889 /* Mark this page used in the map. */
890 region_add(&reservations->regions, idx, idx + 1);
894 static struct page *alloc_huge_page(struct vm_area_struct *vma,
895 unsigned long addr, int avoid_reserve)
897 struct hstate *h = hstate_vma(vma);
898 struct page *page;
899 struct address_space *mapping = vma->vm_file->f_mapping;
900 struct inode *inode = mapping->host;
901 unsigned int chg;
904 * Processes that did not create the mapping will have no reserves and
905 * will not have accounted against quota. Check that the quota can be
906 * made before satisfying the allocation
907 * MAP_NORESERVE mappings may also need pages and quota allocated
908 * if no reserve mapping overlaps.
910 chg = vma_needs_reservation(h, vma, addr);
911 if (chg < 0)
912 return ERR_PTR(chg);
913 if (chg)
914 if (hugetlb_get_quota(inode->i_mapping, chg))
915 return ERR_PTR(-ENOSPC);
917 spin_lock(&hugetlb_lock);
918 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
919 spin_unlock(&hugetlb_lock);
921 if (!page) {
922 page = alloc_buddy_huge_page(h, vma, addr);
923 if (!page) {
924 hugetlb_put_quota(inode->i_mapping, chg);
925 return ERR_PTR(-VM_FAULT_OOM);
929 set_page_refcounted(page);
930 set_page_private(page, (unsigned long) mapping);
932 vma_commit_reservation(h, vma, addr);
934 return page;
937 __attribute__((weak)) int alloc_bootmem_huge_page(struct hstate *h)
939 struct huge_bootmem_page *m;
940 int nr_nodes = nodes_weight(node_online_map);
942 while (nr_nodes) {
943 void *addr;
945 addr = __alloc_bootmem_node_nopanic(
946 NODE_DATA(h->hugetlb_next_nid),
947 huge_page_size(h), huge_page_size(h), 0);
949 if (addr) {
951 * Use the beginning of the huge page to store the
952 * huge_bootmem_page struct (until gather_bootmem
953 * puts them into the mem_map).
955 m = addr;
956 if (m)
957 goto found;
959 hstate_next_node(h);
960 nr_nodes--;
962 return 0;
964 found:
965 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
966 /* Put them into a private list first because mem_map is not up yet */
967 list_add(&m->list, &huge_boot_pages);
968 m->hstate = h;
969 return 1;
972 /* Put bootmem huge pages into the standard lists after mem_map is up */
973 static void __init gather_bootmem_prealloc(void)
975 struct huge_bootmem_page *m;
977 list_for_each_entry(m, &huge_boot_pages, list) {
978 struct page *page = virt_to_page(m);
979 struct hstate *h = m->hstate;
980 __ClearPageReserved(page);
981 WARN_ON(page_count(page) != 1);
982 prep_compound_page(page, h->order);
983 prep_new_huge_page(h, page, page_to_nid(page));
987 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
989 unsigned long i;
991 for (i = 0; i < h->max_huge_pages; ++i) {
992 if (h->order >= MAX_ORDER) {
993 if (!alloc_bootmem_huge_page(h))
994 break;
995 } else if (!alloc_fresh_huge_page(h))
996 break;
998 h->max_huge_pages = i;
1001 static void __init hugetlb_init_hstates(void)
1003 struct hstate *h;
1005 for_each_hstate(h) {
1006 /* oversize hugepages were init'ed in early boot */
1007 if (h->order < MAX_ORDER)
1008 hugetlb_hstate_alloc_pages(h);
1012 static char * __init memfmt(char *buf, unsigned long n)
1014 if (n >= (1UL << 30))
1015 sprintf(buf, "%lu GB", n >> 30);
1016 else if (n >= (1UL << 20))
1017 sprintf(buf, "%lu MB", n >> 20);
1018 else
1019 sprintf(buf, "%lu KB", n >> 10);
1020 return buf;
1023 static void __init report_hugepages(void)
1025 struct hstate *h;
1027 for_each_hstate(h) {
1028 char buf[32];
1029 printk(KERN_INFO "HugeTLB registered %s page size, "
1030 "pre-allocated %ld pages\n",
1031 memfmt(buf, huge_page_size(h)),
1032 h->free_huge_pages);
1036 #ifdef CONFIG_HIGHMEM
1037 static void try_to_free_low(struct hstate *h, unsigned long count)
1039 int i;
1041 if (h->order >= MAX_ORDER)
1042 return;
1044 for (i = 0; i < MAX_NUMNODES; ++i) {
1045 struct page *page, *next;
1046 struct list_head *freel = &h->hugepage_freelists[i];
1047 list_for_each_entry_safe(page, next, freel, lru) {
1048 if (count >= h->nr_huge_pages)
1049 return;
1050 if (PageHighMem(page))
1051 continue;
1052 list_del(&page->lru);
1053 update_and_free_page(h, page);
1054 h->free_huge_pages--;
1055 h->free_huge_pages_node[page_to_nid(page)]--;
1059 #else
1060 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1063 #endif
1065 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1066 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1068 unsigned long min_count, ret;
1070 if (h->order >= MAX_ORDER)
1071 return h->max_huge_pages;
1074 * Increase the pool size
1075 * First take pages out of surplus state. Then make up the
1076 * remaining difference by allocating fresh huge pages.
1078 * We might race with alloc_buddy_huge_page() here and be unable
1079 * to convert a surplus huge page to a normal huge page. That is
1080 * not critical, though, it just means the overall size of the
1081 * pool might be one hugepage larger than it needs to be, but
1082 * within all the constraints specified by the sysctls.
1084 spin_lock(&hugetlb_lock);
1085 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1086 if (!adjust_pool_surplus(h, -1))
1087 break;
1090 while (count > persistent_huge_pages(h)) {
1092 * If this allocation races such that we no longer need the
1093 * page, free_huge_page will handle it by freeing the page
1094 * and reducing the surplus.
1096 spin_unlock(&hugetlb_lock);
1097 ret = alloc_fresh_huge_page(h);
1098 spin_lock(&hugetlb_lock);
1099 if (!ret)
1100 goto out;
1105 * Decrease the pool size
1106 * First return free pages to the buddy allocator (being careful
1107 * to keep enough around to satisfy reservations). Then place
1108 * pages into surplus state as needed so the pool will shrink
1109 * to the desired size as pages become free.
1111 * By placing pages into the surplus state independent of the
1112 * overcommit value, we are allowing the surplus pool size to
1113 * exceed overcommit. There are few sane options here. Since
1114 * alloc_buddy_huge_page() is checking the global counter,
1115 * though, we'll note that we're not allowed to exceed surplus
1116 * and won't grow the pool anywhere else. Not until one of the
1117 * sysctls are changed, or the surplus pages go out of use.
1119 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1120 min_count = max(count, min_count);
1121 try_to_free_low(h, min_count);
1122 while (min_count < persistent_huge_pages(h)) {
1123 struct page *page = dequeue_huge_page(h);
1124 if (!page)
1125 break;
1126 update_and_free_page(h, page);
1128 while (count < persistent_huge_pages(h)) {
1129 if (!adjust_pool_surplus(h, 1))
1130 break;
1132 out:
1133 ret = persistent_huge_pages(h);
1134 spin_unlock(&hugetlb_lock);
1135 return ret;
1138 #define HSTATE_ATTR_RO(_name) \
1139 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1141 #define HSTATE_ATTR(_name) \
1142 static struct kobj_attribute _name##_attr = \
1143 __ATTR(_name, 0644, _name##_show, _name##_store)
1145 static struct kobject *hugepages_kobj;
1146 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1148 static struct hstate *kobj_to_hstate(struct kobject *kobj)
1150 int i;
1151 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1152 if (hstate_kobjs[i] == kobj)
1153 return &hstates[i];
1154 BUG();
1155 return NULL;
1158 static ssize_t nr_hugepages_show(struct kobject *kobj,
1159 struct kobj_attribute *attr, char *buf)
1161 struct hstate *h = kobj_to_hstate(kobj);
1162 return sprintf(buf, "%lu\n", h->nr_huge_pages);
1164 static ssize_t nr_hugepages_store(struct kobject *kobj,
1165 struct kobj_attribute *attr, const char *buf, size_t count)
1167 int err;
1168 unsigned long input;
1169 struct hstate *h = kobj_to_hstate(kobj);
1171 err = strict_strtoul(buf, 10, &input);
1172 if (err)
1173 return 0;
1175 h->max_huge_pages = set_max_huge_pages(h, input);
1177 return count;
1179 HSTATE_ATTR(nr_hugepages);
1181 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1182 struct kobj_attribute *attr, char *buf)
1184 struct hstate *h = kobj_to_hstate(kobj);
1185 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1187 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1188 struct kobj_attribute *attr, const char *buf, size_t count)
1190 int err;
1191 unsigned long input;
1192 struct hstate *h = kobj_to_hstate(kobj);
1194 err = strict_strtoul(buf, 10, &input);
1195 if (err)
1196 return 0;
1198 spin_lock(&hugetlb_lock);
1199 h->nr_overcommit_huge_pages = input;
1200 spin_unlock(&hugetlb_lock);
1202 return count;
1204 HSTATE_ATTR(nr_overcommit_hugepages);
1206 static ssize_t free_hugepages_show(struct kobject *kobj,
1207 struct kobj_attribute *attr, char *buf)
1209 struct hstate *h = kobj_to_hstate(kobj);
1210 return sprintf(buf, "%lu\n", h->free_huge_pages);
1212 HSTATE_ATTR_RO(free_hugepages);
1214 static ssize_t resv_hugepages_show(struct kobject *kobj,
1215 struct kobj_attribute *attr, char *buf)
1217 struct hstate *h = kobj_to_hstate(kobj);
1218 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1220 HSTATE_ATTR_RO(resv_hugepages);
1222 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1223 struct kobj_attribute *attr, char *buf)
1225 struct hstate *h = kobj_to_hstate(kobj);
1226 return sprintf(buf, "%lu\n", h->surplus_huge_pages);
1228 HSTATE_ATTR_RO(surplus_hugepages);
1230 static struct attribute *hstate_attrs[] = {
1231 &nr_hugepages_attr.attr,
1232 &nr_overcommit_hugepages_attr.attr,
1233 &free_hugepages_attr.attr,
1234 &resv_hugepages_attr.attr,
1235 &surplus_hugepages_attr.attr,
1236 NULL,
1239 static struct attribute_group hstate_attr_group = {
1240 .attrs = hstate_attrs,
1243 static int __init hugetlb_sysfs_add_hstate(struct hstate *h)
1245 int retval;
1247 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name,
1248 hugepages_kobj);
1249 if (!hstate_kobjs[h - hstates])
1250 return -ENOMEM;
1252 retval = sysfs_create_group(hstate_kobjs[h - hstates],
1253 &hstate_attr_group);
1254 if (retval)
1255 kobject_put(hstate_kobjs[h - hstates]);
1257 return retval;
1260 static void __init hugetlb_sysfs_init(void)
1262 struct hstate *h;
1263 int err;
1265 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1266 if (!hugepages_kobj)
1267 return;
1269 for_each_hstate(h) {
1270 err = hugetlb_sysfs_add_hstate(h);
1271 if (err)
1272 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1273 h->name);
1277 static void __exit hugetlb_exit(void)
1279 struct hstate *h;
1281 for_each_hstate(h) {
1282 kobject_put(hstate_kobjs[h - hstates]);
1285 kobject_put(hugepages_kobj);
1287 module_exit(hugetlb_exit);
1289 static int __init hugetlb_init(void)
1291 /* Some platform decide whether they support huge pages at boot
1292 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1293 * there is no such support
1295 if (HPAGE_SHIFT == 0)
1296 return 0;
1298 if (!size_to_hstate(default_hstate_size)) {
1299 default_hstate_size = HPAGE_SIZE;
1300 if (!size_to_hstate(default_hstate_size))
1301 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1303 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1304 if (default_hstate_max_huge_pages)
1305 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1307 hugetlb_init_hstates();
1309 gather_bootmem_prealloc();
1311 report_hugepages();
1313 hugetlb_sysfs_init();
1315 return 0;
1317 module_init(hugetlb_init);
1319 /* Should be called on processing a hugepagesz=... option */
1320 void __init hugetlb_add_hstate(unsigned order)
1322 struct hstate *h;
1323 unsigned long i;
1325 if (size_to_hstate(PAGE_SIZE << order)) {
1326 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1327 return;
1329 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1330 BUG_ON(order == 0);
1331 h = &hstates[max_hstate++];
1332 h->order = order;
1333 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1334 h->nr_huge_pages = 0;
1335 h->free_huge_pages = 0;
1336 for (i = 0; i < MAX_NUMNODES; ++i)
1337 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1338 h->hugetlb_next_nid = first_node(node_online_map);
1339 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1340 huge_page_size(h)/1024);
1342 parsed_hstate = h;
1345 static int __init hugetlb_nrpages_setup(char *s)
1347 unsigned long *mhp;
1348 static unsigned long *last_mhp;
1351 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1352 * so this hugepages= parameter goes to the "default hstate".
1354 if (!max_hstate)
1355 mhp = &default_hstate_max_huge_pages;
1356 else
1357 mhp = &parsed_hstate->max_huge_pages;
1359 if (mhp == last_mhp) {
1360 printk(KERN_WARNING "hugepages= specified twice without "
1361 "interleaving hugepagesz=, ignoring\n");
1362 return 1;
1365 if (sscanf(s, "%lu", mhp) <= 0)
1366 *mhp = 0;
1369 * Global state is always initialized later in hugetlb_init.
1370 * But we need to allocate >= MAX_ORDER hstates here early to still
1371 * use the bootmem allocator.
1373 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1374 hugetlb_hstate_alloc_pages(parsed_hstate);
1376 last_mhp = mhp;
1378 return 1;
1380 __setup("hugepages=", hugetlb_nrpages_setup);
1382 static int __init hugetlb_default_setup(char *s)
1384 default_hstate_size = memparse(s, &s);
1385 return 1;
1387 __setup("default_hugepagesz=", hugetlb_default_setup);
1389 static unsigned int cpuset_mems_nr(unsigned int *array)
1391 int node;
1392 unsigned int nr = 0;
1394 for_each_node_mask(node, cpuset_current_mems_allowed)
1395 nr += array[node];
1397 return nr;
1400 #ifdef CONFIG_SYSCTL
1401 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1402 struct file *file, void __user *buffer,
1403 size_t *length, loff_t *ppos)
1405 struct hstate *h = &default_hstate;
1406 unsigned long tmp;
1408 if (!write)
1409 tmp = h->max_huge_pages;
1411 table->data = &tmp;
1412 table->maxlen = sizeof(unsigned long);
1413 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1415 if (write)
1416 h->max_huge_pages = set_max_huge_pages(h, tmp);
1418 return 0;
1421 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1422 struct file *file, void __user *buffer,
1423 size_t *length, loff_t *ppos)
1425 proc_dointvec(table, write, file, buffer, length, ppos);
1426 if (hugepages_treat_as_movable)
1427 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1428 else
1429 htlb_alloc_mask = GFP_HIGHUSER;
1430 return 0;
1433 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1434 struct file *file, void __user *buffer,
1435 size_t *length, loff_t *ppos)
1437 struct hstate *h = &default_hstate;
1438 unsigned long tmp;
1440 if (!write)
1441 tmp = h->nr_overcommit_huge_pages;
1443 table->data = &tmp;
1444 table->maxlen = sizeof(unsigned long);
1445 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1447 if (write) {
1448 spin_lock(&hugetlb_lock);
1449 h->nr_overcommit_huge_pages = tmp;
1450 spin_unlock(&hugetlb_lock);
1453 return 0;
1456 #endif /* CONFIG_SYSCTL */
1458 int hugetlb_report_meminfo(char *buf)
1460 struct hstate *h = &default_hstate;
1461 return sprintf(buf,
1462 "HugePages_Total: %5lu\n"
1463 "HugePages_Free: %5lu\n"
1464 "HugePages_Rsvd: %5lu\n"
1465 "HugePages_Surp: %5lu\n"
1466 "Hugepagesize: %5lu kB\n",
1467 h->nr_huge_pages,
1468 h->free_huge_pages,
1469 h->resv_huge_pages,
1470 h->surplus_huge_pages,
1471 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1474 int hugetlb_report_node_meminfo(int nid, char *buf)
1476 struct hstate *h = &default_hstate;
1477 return sprintf(buf,
1478 "Node %d HugePages_Total: %5u\n"
1479 "Node %d HugePages_Free: %5u\n"
1480 "Node %d HugePages_Surp: %5u\n",
1481 nid, h->nr_huge_pages_node[nid],
1482 nid, h->free_huge_pages_node[nid],
1483 nid, h->surplus_huge_pages_node[nid]);
1486 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1487 unsigned long hugetlb_total_pages(void)
1489 struct hstate *h = &default_hstate;
1490 return h->nr_huge_pages * pages_per_huge_page(h);
1493 static int hugetlb_acct_memory(struct hstate *h, long delta)
1495 int ret = -ENOMEM;
1497 spin_lock(&hugetlb_lock);
1499 * When cpuset is configured, it breaks the strict hugetlb page
1500 * reservation as the accounting is done on a global variable. Such
1501 * reservation is completely rubbish in the presence of cpuset because
1502 * the reservation is not checked against page availability for the
1503 * current cpuset. Application can still potentially OOM'ed by kernel
1504 * with lack of free htlb page in cpuset that the task is in.
1505 * Attempt to enforce strict accounting with cpuset is almost
1506 * impossible (or too ugly) because cpuset is too fluid that
1507 * task or memory node can be dynamically moved between cpusets.
1509 * The change of semantics for shared hugetlb mapping with cpuset is
1510 * undesirable. However, in order to preserve some of the semantics,
1511 * we fall back to check against current free page availability as
1512 * a best attempt and hopefully to minimize the impact of changing
1513 * semantics that cpuset has.
1515 if (delta > 0) {
1516 if (gather_surplus_pages(h, delta) < 0)
1517 goto out;
1519 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1520 return_unused_surplus_pages(h, delta);
1521 goto out;
1525 ret = 0;
1526 if (delta < 0)
1527 return_unused_surplus_pages(h, (unsigned long) -delta);
1529 out:
1530 spin_unlock(&hugetlb_lock);
1531 return ret;
1534 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1536 struct resv_map *reservations = vma_resv_map(vma);
1539 * This new VMA should share its siblings reservation map if present.
1540 * The VMA will only ever have a valid reservation map pointer where
1541 * it is being copied for another still existing VMA. As that VMA
1542 * has a reference to the reservation map it cannot dissappear until
1543 * after this open call completes. It is therefore safe to take a
1544 * new reference here without additional locking.
1546 if (reservations)
1547 kref_get(&reservations->refs);
1550 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1552 struct hstate *h = hstate_vma(vma);
1553 struct resv_map *reservations = vma_resv_map(vma);
1554 unsigned long reserve;
1555 unsigned long start;
1556 unsigned long end;
1558 if (reservations) {
1559 start = vma_hugecache_offset(h, vma, vma->vm_start);
1560 end = vma_hugecache_offset(h, vma, vma->vm_end);
1562 reserve = (end - start) -
1563 region_count(&reservations->regions, start, end);
1565 kref_put(&reservations->refs, resv_map_release);
1567 if (reserve) {
1568 hugetlb_acct_memory(h, -reserve);
1569 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
1575 * We cannot handle pagefaults against hugetlb pages at all. They cause
1576 * handle_mm_fault() to try to instantiate regular-sized pages in the
1577 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1578 * this far.
1580 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1582 BUG();
1583 return 0;
1586 struct vm_operations_struct hugetlb_vm_ops = {
1587 .fault = hugetlb_vm_op_fault,
1588 .open = hugetlb_vm_op_open,
1589 .close = hugetlb_vm_op_close,
1592 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1593 int writable)
1595 pte_t entry;
1597 if (writable) {
1598 entry =
1599 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1600 } else {
1601 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1603 entry = pte_mkyoung(entry);
1604 entry = pte_mkhuge(entry);
1606 return entry;
1609 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1610 unsigned long address, pte_t *ptep)
1612 pte_t entry;
1614 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1615 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1616 update_mmu_cache(vma, address, entry);
1621 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1622 struct vm_area_struct *vma)
1624 pte_t *src_pte, *dst_pte, entry;
1625 struct page *ptepage;
1626 unsigned long addr;
1627 int cow;
1628 struct hstate *h = hstate_vma(vma);
1629 unsigned long sz = huge_page_size(h);
1631 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1633 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1634 src_pte = huge_pte_offset(src, addr);
1635 if (!src_pte)
1636 continue;
1637 dst_pte = huge_pte_alloc(dst, addr, sz);
1638 if (!dst_pte)
1639 goto nomem;
1641 /* If the pagetables are shared don't copy or take references */
1642 if (dst_pte == src_pte)
1643 continue;
1645 spin_lock(&dst->page_table_lock);
1646 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1647 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1648 if (cow)
1649 huge_ptep_set_wrprotect(src, addr, src_pte);
1650 entry = huge_ptep_get(src_pte);
1651 ptepage = pte_page(entry);
1652 get_page(ptepage);
1653 set_huge_pte_at(dst, addr, dst_pte, entry);
1655 spin_unlock(&src->page_table_lock);
1656 spin_unlock(&dst->page_table_lock);
1658 return 0;
1660 nomem:
1661 return -ENOMEM;
1664 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1665 unsigned long end, struct page *ref_page)
1667 struct mm_struct *mm = vma->vm_mm;
1668 unsigned long address;
1669 pte_t *ptep;
1670 pte_t pte;
1671 struct page *page;
1672 struct page *tmp;
1673 struct hstate *h = hstate_vma(vma);
1674 unsigned long sz = huge_page_size(h);
1677 * A page gathering list, protected by per file i_mmap_lock. The
1678 * lock is used to avoid list corruption from multiple unmapping
1679 * of the same page since we are using page->lru.
1681 LIST_HEAD(page_list);
1683 WARN_ON(!is_vm_hugetlb_page(vma));
1684 BUG_ON(start & ~huge_page_mask(h));
1685 BUG_ON(end & ~huge_page_mask(h));
1687 mmu_notifier_invalidate_range_start(mm, start, end);
1688 spin_lock(&mm->page_table_lock);
1689 for (address = start; address < end; address += sz) {
1690 ptep = huge_pte_offset(mm, address);
1691 if (!ptep)
1692 continue;
1694 if (huge_pmd_unshare(mm, &address, ptep))
1695 continue;
1698 * If a reference page is supplied, it is because a specific
1699 * page is being unmapped, not a range. Ensure the page we
1700 * are about to unmap is the actual page of interest.
1702 if (ref_page) {
1703 pte = huge_ptep_get(ptep);
1704 if (huge_pte_none(pte))
1705 continue;
1706 page = pte_page(pte);
1707 if (page != ref_page)
1708 continue;
1711 * Mark the VMA as having unmapped its page so that
1712 * future faults in this VMA will fail rather than
1713 * looking like data was lost
1715 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1718 pte = huge_ptep_get_and_clear(mm, address, ptep);
1719 if (huge_pte_none(pte))
1720 continue;
1722 page = pte_page(pte);
1723 if (pte_dirty(pte))
1724 set_page_dirty(page);
1725 list_add(&page->lru, &page_list);
1727 spin_unlock(&mm->page_table_lock);
1728 flush_tlb_range(vma, start, end);
1729 mmu_notifier_invalidate_range_end(mm, start, end);
1730 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1731 list_del(&page->lru);
1732 put_page(page);
1736 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1737 unsigned long end, struct page *ref_page)
1739 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1740 __unmap_hugepage_range(vma, start, end, ref_page);
1741 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1745 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1746 * mappping it owns the reserve page for. The intention is to unmap the page
1747 * from other VMAs and let the children be SIGKILLed if they are faulting the
1748 * same region.
1750 int unmap_ref_private(struct mm_struct *mm,
1751 struct vm_area_struct *vma,
1752 struct page *page,
1753 unsigned long address)
1755 struct vm_area_struct *iter_vma;
1756 struct address_space *mapping;
1757 struct prio_tree_iter iter;
1758 pgoff_t pgoff;
1761 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1762 * from page cache lookup which is in HPAGE_SIZE units.
1764 address = address & huge_page_mask(hstate_vma(vma));
1765 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1766 + (vma->vm_pgoff >> PAGE_SHIFT);
1767 mapping = (struct address_space *)page_private(page);
1769 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1770 /* Do not unmap the current VMA */
1771 if (iter_vma == vma)
1772 continue;
1775 * Unmap the page from other VMAs without their own reserves.
1776 * They get marked to be SIGKILLed if they fault in these
1777 * areas. This is because a future no-page fault on this VMA
1778 * could insert a zeroed page instead of the data existing
1779 * from the time of fork. This would look like data corruption
1781 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1782 unmap_hugepage_range(iter_vma,
1783 address, address + HPAGE_SIZE,
1784 page);
1787 return 1;
1790 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1791 unsigned long address, pte_t *ptep, pte_t pte,
1792 struct page *pagecache_page)
1794 struct hstate *h = hstate_vma(vma);
1795 struct page *old_page, *new_page;
1796 int avoidcopy;
1797 int outside_reserve = 0;
1799 old_page = pte_page(pte);
1801 retry_avoidcopy:
1802 /* If no-one else is actually using this page, avoid the copy
1803 * and just make the page writable */
1804 avoidcopy = (page_count(old_page) == 1);
1805 if (avoidcopy) {
1806 set_huge_ptep_writable(vma, address, ptep);
1807 return 0;
1811 * If the process that created a MAP_PRIVATE mapping is about to
1812 * perform a COW due to a shared page count, attempt to satisfy
1813 * the allocation without using the existing reserves. The pagecache
1814 * page is used to determine if the reserve at this address was
1815 * consumed or not. If reserves were used, a partial faulted mapping
1816 * at the time of fork() could consume its reserves on COW instead
1817 * of the full address range.
1819 if (!(vma->vm_flags & VM_SHARED) &&
1820 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1821 old_page != pagecache_page)
1822 outside_reserve = 1;
1824 page_cache_get(old_page);
1825 new_page = alloc_huge_page(vma, address, outside_reserve);
1827 if (IS_ERR(new_page)) {
1828 page_cache_release(old_page);
1831 * If a process owning a MAP_PRIVATE mapping fails to COW,
1832 * it is due to references held by a child and an insufficient
1833 * huge page pool. To guarantee the original mappers
1834 * reliability, unmap the page from child processes. The child
1835 * may get SIGKILLed if it later faults.
1837 if (outside_reserve) {
1838 BUG_ON(huge_pte_none(pte));
1839 if (unmap_ref_private(mm, vma, old_page, address)) {
1840 BUG_ON(page_count(old_page) != 1);
1841 BUG_ON(huge_pte_none(pte));
1842 goto retry_avoidcopy;
1844 WARN_ON_ONCE(1);
1847 return -PTR_ERR(new_page);
1850 spin_unlock(&mm->page_table_lock);
1851 copy_huge_page(new_page, old_page, address, vma);
1852 __SetPageUptodate(new_page);
1853 spin_lock(&mm->page_table_lock);
1855 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
1856 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
1857 /* Break COW */
1858 huge_ptep_clear_flush(vma, address, ptep);
1859 set_huge_pte_at(mm, address, ptep,
1860 make_huge_pte(vma, new_page, 1));
1861 /* Make the old page be freed below */
1862 new_page = old_page;
1864 page_cache_release(new_page);
1865 page_cache_release(old_page);
1866 return 0;
1869 /* Return the pagecache page at a given address within a VMA */
1870 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
1871 struct vm_area_struct *vma, unsigned long address)
1873 struct address_space *mapping;
1874 pgoff_t idx;
1876 mapping = vma->vm_file->f_mapping;
1877 idx = vma_hugecache_offset(h, vma, address);
1879 return find_lock_page(mapping, idx);
1882 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1883 unsigned long address, pte_t *ptep, int write_access)
1885 struct hstate *h = hstate_vma(vma);
1886 int ret = VM_FAULT_SIGBUS;
1887 pgoff_t idx;
1888 unsigned long size;
1889 struct page *page;
1890 struct address_space *mapping;
1891 pte_t new_pte;
1894 * Currently, we are forced to kill the process in the event the
1895 * original mapper has unmapped pages from the child due to a failed
1896 * COW. Warn that such a situation has occured as it may not be obvious
1898 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
1899 printk(KERN_WARNING
1900 "PID %d killed due to inadequate hugepage pool\n",
1901 current->pid);
1902 return ret;
1905 mapping = vma->vm_file->f_mapping;
1906 idx = vma_hugecache_offset(h, vma, address);
1909 * Use page lock to guard against racing truncation
1910 * before we get page_table_lock.
1912 retry:
1913 page = find_lock_page(mapping, idx);
1914 if (!page) {
1915 size = i_size_read(mapping->host) >> huge_page_shift(h);
1916 if (idx >= size)
1917 goto out;
1918 page = alloc_huge_page(vma, address, 0);
1919 if (IS_ERR(page)) {
1920 ret = -PTR_ERR(page);
1921 goto out;
1923 clear_huge_page(page, address, huge_page_size(h));
1924 __SetPageUptodate(page);
1926 if (vma->vm_flags & VM_SHARED) {
1927 int err;
1928 struct inode *inode = mapping->host;
1930 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
1931 if (err) {
1932 put_page(page);
1933 if (err == -EEXIST)
1934 goto retry;
1935 goto out;
1938 spin_lock(&inode->i_lock);
1939 inode->i_blocks += blocks_per_huge_page(h);
1940 spin_unlock(&inode->i_lock);
1941 } else
1942 lock_page(page);
1946 * If we are going to COW a private mapping later, we examine the
1947 * pending reservations for this page now. This will ensure that
1948 * any allocations necessary to record that reservation occur outside
1949 * the spinlock.
1951 if (write_access && !(vma->vm_flags & VM_SHARED))
1952 if (vma_needs_reservation(h, vma, address) < 0) {
1953 ret = VM_FAULT_OOM;
1954 goto backout_unlocked;
1957 spin_lock(&mm->page_table_lock);
1958 size = i_size_read(mapping->host) >> huge_page_shift(h);
1959 if (idx >= size)
1960 goto backout;
1962 ret = 0;
1963 if (!huge_pte_none(huge_ptep_get(ptep)))
1964 goto backout;
1966 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
1967 && (vma->vm_flags & VM_SHARED)));
1968 set_huge_pte_at(mm, address, ptep, new_pte);
1970 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1971 /* Optimization, do the COW without a second fault */
1972 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
1975 spin_unlock(&mm->page_table_lock);
1976 unlock_page(page);
1977 out:
1978 return ret;
1980 backout:
1981 spin_unlock(&mm->page_table_lock);
1982 backout_unlocked:
1983 unlock_page(page);
1984 put_page(page);
1985 goto out;
1988 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1989 unsigned long address, int write_access)
1991 pte_t *ptep;
1992 pte_t entry;
1993 int ret;
1994 struct page *pagecache_page = NULL;
1995 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
1996 struct hstate *h = hstate_vma(vma);
1998 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
1999 if (!ptep)
2000 return VM_FAULT_OOM;
2003 * Serialize hugepage allocation and instantiation, so that we don't
2004 * get spurious allocation failures if two CPUs race to instantiate
2005 * the same page in the page cache.
2007 mutex_lock(&hugetlb_instantiation_mutex);
2008 entry = huge_ptep_get(ptep);
2009 if (huge_pte_none(entry)) {
2010 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
2011 goto out_mutex;
2014 ret = 0;
2017 * If we are going to COW the mapping later, we examine the pending
2018 * reservations for this page now. This will ensure that any
2019 * allocations necessary to record that reservation occur outside the
2020 * spinlock. For private mappings, we also lookup the pagecache
2021 * page now as it is used to determine if a reservation has been
2022 * consumed.
2024 if (write_access && !pte_write(entry)) {
2025 if (vma_needs_reservation(h, vma, address) < 0) {
2026 ret = VM_FAULT_OOM;
2027 goto out_mutex;
2030 if (!(vma->vm_flags & VM_SHARED))
2031 pagecache_page = hugetlbfs_pagecache_page(h,
2032 vma, address);
2035 spin_lock(&mm->page_table_lock);
2036 /* Check for a racing update before calling hugetlb_cow */
2037 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2038 goto out_page_table_lock;
2041 if (write_access) {
2042 if (!pte_write(entry)) {
2043 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2044 pagecache_page);
2045 goto out_page_table_lock;
2047 entry = pte_mkdirty(entry);
2049 entry = pte_mkyoung(entry);
2050 if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access))
2051 update_mmu_cache(vma, address, entry);
2053 out_page_table_lock:
2054 spin_unlock(&mm->page_table_lock);
2056 if (pagecache_page) {
2057 unlock_page(pagecache_page);
2058 put_page(pagecache_page);
2061 out_mutex:
2062 mutex_unlock(&hugetlb_instantiation_mutex);
2064 return ret;
2067 /* Can be overriden by architectures */
2068 __attribute__((weak)) struct page *
2069 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2070 pud_t *pud, int write)
2072 BUG();
2073 return NULL;
2076 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2077 struct page **pages, struct vm_area_struct **vmas,
2078 unsigned long *position, int *length, int i,
2079 int write)
2081 unsigned long pfn_offset;
2082 unsigned long vaddr = *position;
2083 int remainder = *length;
2084 struct hstate *h = hstate_vma(vma);
2086 spin_lock(&mm->page_table_lock);
2087 while (vaddr < vma->vm_end && remainder) {
2088 pte_t *pte;
2089 struct page *page;
2092 * Some archs (sparc64, sh*) have multiple pte_ts to
2093 * each hugepage. We have to make * sure we get the
2094 * first, for the page indexing below to work.
2096 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2098 if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
2099 (write && !pte_write(huge_ptep_get(pte)))) {
2100 int ret;
2102 spin_unlock(&mm->page_table_lock);
2103 ret = hugetlb_fault(mm, vma, vaddr, write);
2104 spin_lock(&mm->page_table_lock);
2105 if (!(ret & VM_FAULT_ERROR))
2106 continue;
2108 remainder = 0;
2109 if (!i)
2110 i = -EFAULT;
2111 break;
2114 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2115 page = pte_page(huge_ptep_get(pte));
2116 same_page:
2117 if (pages) {
2118 get_page(page);
2119 pages[i] = page + pfn_offset;
2122 if (vmas)
2123 vmas[i] = vma;
2125 vaddr += PAGE_SIZE;
2126 ++pfn_offset;
2127 --remainder;
2128 ++i;
2129 if (vaddr < vma->vm_end && remainder &&
2130 pfn_offset < pages_per_huge_page(h)) {
2132 * We use pfn_offset to avoid touching the pageframes
2133 * of this compound page.
2135 goto same_page;
2138 spin_unlock(&mm->page_table_lock);
2139 *length = remainder;
2140 *position = vaddr;
2142 return i;
2145 void hugetlb_change_protection(struct vm_area_struct *vma,
2146 unsigned long address, unsigned long end, pgprot_t newprot)
2148 struct mm_struct *mm = vma->vm_mm;
2149 unsigned long start = address;
2150 pte_t *ptep;
2151 pte_t pte;
2152 struct hstate *h = hstate_vma(vma);
2154 BUG_ON(address >= end);
2155 flush_cache_range(vma, address, end);
2157 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2158 spin_lock(&mm->page_table_lock);
2159 for (; address < end; address += huge_page_size(h)) {
2160 ptep = huge_pte_offset(mm, address);
2161 if (!ptep)
2162 continue;
2163 if (huge_pmd_unshare(mm, &address, ptep))
2164 continue;
2165 if (!huge_pte_none(huge_ptep_get(ptep))) {
2166 pte = huge_ptep_get_and_clear(mm, address, ptep);
2167 pte = pte_mkhuge(pte_modify(pte, newprot));
2168 set_huge_pte_at(mm, address, ptep, pte);
2171 spin_unlock(&mm->page_table_lock);
2172 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2174 flush_tlb_range(vma, start, end);
2177 int hugetlb_reserve_pages(struct inode *inode,
2178 long from, long to,
2179 struct vm_area_struct *vma)
2181 long ret, chg;
2182 struct hstate *h = hstate_inode(inode);
2184 if (vma && vma->vm_flags & VM_NORESERVE)
2185 return 0;
2188 * Shared mappings base their reservation on the number of pages that
2189 * are already allocated on behalf of the file. Private mappings need
2190 * to reserve the full area even if read-only as mprotect() may be
2191 * called to make the mapping read-write. Assume !vma is a shm mapping
2193 if (!vma || vma->vm_flags & VM_SHARED)
2194 chg = region_chg(&inode->i_mapping->private_list, from, to);
2195 else {
2196 struct resv_map *resv_map = resv_map_alloc();
2197 if (!resv_map)
2198 return -ENOMEM;
2200 chg = to - from;
2202 set_vma_resv_map(vma, resv_map);
2203 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2206 if (chg < 0)
2207 return chg;
2209 if (hugetlb_get_quota(inode->i_mapping, chg))
2210 return -ENOSPC;
2211 ret = hugetlb_acct_memory(h, chg);
2212 if (ret < 0) {
2213 hugetlb_put_quota(inode->i_mapping, chg);
2214 return ret;
2216 if (!vma || vma->vm_flags & VM_SHARED)
2217 region_add(&inode->i_mapping->private_list, from, to);
2218 return 0;
2221 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2223 struct hstate *h = hstate_inode(inode);
2224 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2226 spin_lock(&inode->i_lock);
2227 inode->i_blocks -= blocks_per_huge_page(h);
2228 spin_unlock(&inode->i_lock);
2230 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2231 hugetlb_acct_memory(h, -(chg - freed));