block: Honor the gfp_mask for alloc_page() in blkdev_issue_discard()
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / hugetlb.c
blob65f38c218207231e0bf5b612ccacc5858be1b4e0
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 <linux/node.h>
28 #include "internal.h"
30 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
31 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
32 unsigned long hugepages_treat_as_movable;
34 static int max_hstate;
35 unsigned int default_hstate_idx;
36 struct hstate hstates[HUGE_MAX_HSTATE];
38 __initdata LIST_HEAD(huge_boot_pages);
40 /* for command line parsing */
41 static struct hstate * __initdata parsed_hstate;
42 static unsigned long __initdata default_hstate_max_huge_pages;
43 static unsigned long __initdata default_hstate_size;
45 #define for_each_hstate(h) \
46 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
49 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
51 static DEFINE_SPINLOCK(hugetlb_lock);
54 * Region tracking -- allows tracking of reservations and instantiated pages
55 * across the pages in a mapping.
57 * The region data structures are protected by a combination of the mmap_sem
58 * and the hugetlb_instantion_mutex. To access or modify a region the caller
59 * must either hold the mmap_sem for write, or the mmap_sem for read and
60 * the hugetlb_instantiation mutex:
62 * down_write(&mm->mmap_sem);
63 * or
64 * down_read(&mm->mmap_sem);
65 * mutex_lock(&hugetlb_instantiation_mutex);
67 struct file_region {
68 struct list_head link;
69 long from;
70 long to;
73 static long region_add(struct list_head *head, long f, long t)
75 struct file_region *rg, *nrg, *trg;
77 /* Locate the region we are either in or before. */
78 list_for_each_entry(rg, head, link)
79 if (f <= rg->to)
80 break;
82 /* Round our left edge to the current segment if it encloses us. */
83 if (f > rg->from)
84 f = rg->from;
86 /* Check for and consume any regions we now overlap with. */
87 nrg = rg;
88 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
89 if (&rg->link == head)
90 break;
91 if (rg->from > t)
92 break;
94 /* If this area reaches higher then extend our area to
95 * include it completely. If this is not the first area
96 * which we intend to reuse, free it. */
97 if (rg->to > t)
98 t = rg->to;
99 if (rg != nrg) {
100 list_del(&rg->link);
101 kfree(rg);
104 nrg->from = f;
105 nrg->to = t;
106 return 0;
109 static long region_chg(struct list_head *head, long f, long t)
111 struct file_region *rg, *nrg;
112 long chg = 0;
114 /* Locate the region we are before or in. */
115 list_for_each_entry(rg, head, link)
116 if (f <= rg->to)
117 break;
119 /* If we are below the current region then a new region is required.
120 * Subtle, allocate a new region at the position but make it zero
121 * size such that we can guarantee to record the reservation. */
122 if (&rg->link == head || t < rg->from) {
123 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
124 if (!nrg)
125 return -ENOMEM;
126 nrg->from = f;
127 nrg->to = f;
128 INIT_LIST_HEAD(&nrg->link);
129 list_add(&nrg->link, rg->link.prev);
131 return t - f;
134 /* Round our left edge to the current segment if it encloses us. */
135 if (f > rg->from)
136 f = rg->from;
137 chg = t - f;
139 /* Check for and consume any regions we now overlap with. */
140 list_for_each_entry(rg, rg->link.prev, link) {
141 if (&rg->link == head)
142 break;
143 if (rg->from > t)
144 return chg;
146 /* We overlap with this area, if it extends futher than
147 * us then we must extend ourselves. Account for its
148 * existing reservation. */
149 if (rg->to > t) {
150 chg += rg->to - t;
151 t = rg->to;
153 chg -= rg->to - rg->from;
155 return chg;
158 static long region_truncate(struct list_head *head, long end)
160 struct file_region *rg, *trg;
161 long chg = 0;
163 /* Locate the region we are either in or before. */
164 list_for_each_entry(rg, head, link)
165 if (end <= rg->to)
166 break;
167 if (&rg->link == head)
168 return 0;
170 /* If we are in the middle of a region then adjust it. */
171 if (end > rg->from) {
172 chg = rg->to - end;
173 rg->to = end;
174 rg = list_entry(rg->link.next, typeof(*rg), link);
177 /* Drop any remaining regions. */
178 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
179 if (&rg->link == head)
180 break;
181 chg += rg->to - rg->from;
182 list_del(&rg->link);
183 kfree(rg);
185 return chg;
188 static long region_count(struct list_head *head, long f, long t)
190 struct file_region *rg;
191 long chg = 0;
193 /* Locate each segment we overlap with, and count that overlap. */
194 list_for_each_entry(rg, head, link) {
195 int seg_from;
196 int seg_to;
198 if (rg->to <= f)
199 continue;
200 if (rg->from >= t)
201 break;
203 seg_from = max(rg->from, f);
204 seg_to = min(rg->to, t);
206 chg += seg_to - seg_from;
209 return chg;
213 * Convert the address within this vma to the page offset within
214 * the mapping, in pagecache page units; huge pages here.
216 static pgoff_t vma_hugecache_offset(struct hstate *h,
217 struct vm_area_struct *vma, unsigned long address)
219 return ((address - vma->vm_start) >> huge_page_shift(h)) +
220 (vma->vm_pgoff >> huge_page_order(h));
224 * Return the size of the pages allocated when backing a VMA. In the majority
225 * cases this will be same size as used by the page table entries.
227 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
229 struct hstate *hstate;
231 if (!is_vm_hugetlb_page(vma))
232 return PAGE_SIZE;
234 hstate = hstate_vma(vma);
236 return 1UL << (hstate->order + PAGE_SHIFT);
238 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
241 * Return the page size being used by the MMU to back a VMA. In the majority
242 * of cases, the page size used by the kernel matches the MMU size. On
243 * architectures where it differs, an architecture-specific version of this
244 * function is required.
246 #ifndef vma_mmu_pagesize
247 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
249 return vma_kernel_pagesize(vma);
251 #endif
254 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
255 * bits of the reservation map pointer, which are always clear due to
256 * alignment.
258 #define HPAGE_RESV_OWNER (1UL << 0)
259 #define HPAGE_RESV_UNMAPPED (1UL << 1)
260 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
263 * These helpers are used to track how many pages are reserved for
264 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
265 * is guaranteed to have their future faults succeed.
267 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
268 * the reserve counters are updated with the hugetlb_lock held. It is safe
269 * to reset the VMA at fork() time as it is not in use yet and there is no
270 * chance of the global counters getting corrupted as a result of the values.
272 * The private mapping reservation is represented in a subtly different
273 * manner to a shared mapping. A shared mapping has a region map associated
274 * with the underlying file, this region map represents the backing file
275 * pages which have ever had a reservation assigned which this persists even
276 * after the page is instantiated. A private mapping has a region map
277 * associated with the original mmap which is attached to all VMAs which
278 * reference it, this region map represents those offsets which have consumed
279 * reservation ie. where pages have been instantiated.
281 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
283 return (unsigned long)vma->vm_private_data;
286 static void set_vma_private_data(struct vm_area_struct *vma,
287 unsigned long value)
289 vma->vm_private_data = (void *)value;
292 struct resv_map {
293 struct kref refs;
294 struct list_head regions;
297 static struct resv_map *resv_map_alloc(void)
299 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
300 if (!resv_map)
301 return NULL;
303 kref_init(&resv_map->refs);
304 INIT_LIST_HEAD(&resv_map->regions);
306 return resv_map;
309 static void resv_map_release(struct kref *ref)
311 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
313 /* Clear out any active regions before we release the map. */
314 region_truncate(&resv_map->regions, 0);
315 kfree(resv_map);
318 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
320 VM_BUG_ON(!is_vm_hugetlb_page(vma));
321 if (!(vma->vm_flags & VM_MAYSHARE))
322 return (struct resv_map *)(get_vma_private_data(vma) &
323 ~HPAGE_RESV_MASK);
324 return NULL;
327 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
329 VM_BUG_ON(!is_vm_hugetlb_page(vma));
330 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
332 set_vma_private_data(vma, (get_vma_private_data(vma) &
333 HPAGE_RESV_MASK) | (unsigned long)map);
336 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
338 VM_BUG_ON(!is_vm_hugetlb_page(vma));
339 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
341 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
344 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
346 VM_BUG_ON(!is_vm_hugetlb_page(vma));
348 return (get_vma_private_data(vma) & flag) != 0;
351 /* Decrement the reserved pages in the hugepage pool by one */
352 static void decrement_hugepage_resv_vma(struct hstate *h,
353 struct vm_area_struct *vma)
355 if (vma->vm_flags & VM_NORESERVE)
356 return;
358 if (vma->vm_flags & VM_MAYSHARE) {
359 /* Shared mappings always use reserves */
360 h->resv_huge_pages--;
361 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
363 * Only the process that called mmap() has reserves for
364 * private mappings.
366 h->resv_huge_pages--;
370 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
371 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
373 VM_BUG_ON(!is_vm_hugetlb_page(vma));
374 if (!(vma->vm_flags & VM_MAYSHARE))
375 vma->vm_private_data = (void *)0;
378 /* Returns true if the VMA has associated reserve pages */
379 static int vma_has_reserves(struct vm_area_struct *vma)
381 if (vma->vm_flags & VM_MAYSHARE)
382 return 1;
383 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
384 return 1;
385 return 0;
388 static void clear_gigantic_page(struct page *page,
389 unsigned long addr, unsigned long sz)
391 int i;
392 struct page *p = page;
394 might_sleep();
395 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
396 cond_resched();
397 clear_user_highpage(p, addr + i * PAGE_SIZE);
400 static void clear_huge_page(struct page *page,
401 unsigned long addr, unsigned long sz)
403 int i;
405 if (unlikely(sz > MAX_ORDER_NR_PAGES)) {
406 clear_gigantic_page(page, addr, sz);
407 return;
410 might_sleep();
411 for (i = 0; i < sz/PAGE_SIZE; i++) {
412 cond_resched();
413 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
417 static void copy_gigantic_page(struct page *dst, struct page *src,
418 unsigned long addr, struct vm_area_struct *vma)
420 int i;
421 struct hstate *h = hstate_vma(vma);
422 struct page *dst_base = dst;
423 struct page *src_base = src;
424 might_sleep();
425 for (i = 0; i < pages_per_huge_page(h); ) {
426 cond_resched();
427 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
429 i++;
430 dst = mem_map_next(dst, dst_base, i);
431 src = mem_map_next(src, src_base, i);
434 static void copy_huge_page(struct page *dst, struct page *src,
435 unsigned long addr, struct vm_area_struct *vma)
437 int i;
438 struct hstate *h = hstate_vma(vma);
440 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
441 copy_gigantic_page(dst, src, addr, vma);
442 return;
445 might_sleep();
446 for (i = 0; i < pages_per_huge_page(h); i++) {
447 cond_resched();
448 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
452 static void enqueue_huge_page(struct hstate *h, struct page *page)
454 int nid = page_to_nid(page);
455 list_add(&page->lru, &h->hugepage_freelists[nid]);
456 h->free_huge_pages++;
457 h->free_huge_pages_node[nid]++;
460 static struct page *dequeue_huge_page_vma(struct hstate *h,
461 struct vm_area_struct *vma,
462 unsigned long address, int avoid_reserve)
464 int nid;
465 struct page *page = NULL;
466 struct mempolicy *mpol;
467 nodemask_t *nodemask;
468 struct zonelist *zonelist = huge_zonelist(vma, address,
469 htlb_alloc_mask, &mpol, &nodemask);
470 struct zone *zone;
471 struct zoneref *z;
474 * A child process with MAP_PRIVATE mappings created by their parent
475 * have no page reserves. This check ensures that reservations are
476 * not "stolen". The child may still get SIGKILLed
478 if (!vma_has_reserves(vma) &&
479 h->free_huge_pages - h->resv_huge_pages == 0)
480 return NULL;
482 /* If reserves cannot be used, ensure enough pages are in the pool */
483 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
484 return NULL;
486 for_each_zone_zonelist_nodemask(zone, z, zonelist,
487 MAX_NR_ZONES - 1, nodemask) {
488 nid = zone_to_nid(zone);
489 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
490 !list_empty(&h->hugepage_freelists[nid])) {
491 page = list_entry(h->hugepage_freelists[nid].next,
492 struct page, lru);
493 list_del(&page->lru);
494 h->free_huge_pages--;
495 h->free_huge_pages_node[nid]--;
497 if (!avoid_reserve)
498 decrement_hugepage_resv_vma(h, vma);
500 break;
503 mpol_cond_put(mpol);
504 return page;
507 static void update_and_free_page(struct hstate *h, struct page *page)
509 int i;
511 VM_BUG_ON(h->order >= MAX_ORDER);
513 h->nr_huge_pages--;
514 h->nr_huge_pages_node[page_to_nid(page)]--;
515 for (i = 0; i < pages_per_huge_page(h); i++) {
516 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
517 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
518 1 << PG_private | 1<< PG_writeback);
520 set_compound_page_dtor(page, NULL);
521 set_page_refcounted(page);
522 arch_release_hugepage(page);
523 __free_pages(page, huge_page_order(h));
526 struct hstate *size_to_hstate(unsigned long size)
528 struct hstate *h;
530 for_each_hstate(h) {
531 if (huge_page_size(h) == size)
532 return h;
534 return NULL;
537 static void free_huge_page(struct page *page)
540 * Can't pass hstate in here because it is called from the
541 * compound page destructor.
543 struct hstate *h = page_hstate(page);
544 int nid = page_to_nid(page);
545 struct address_space *mapping;
547 mapping = (struct address_space *) page_private(page);
548 set_page_private(page, 0);
549 BUG_ON(page_count(page));
550 INIT_LIST_HEAD(&page->lru);
552 spin_lock(&hugetlb_lock);
553 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
554 update_and_free_page(h, page);
555 h->surplus_huge_pages--;
556 h->surplus_huge_pages_node[nid]--;
557 } else {
558 enqueue_huge_page(h, page);
560 spin_unlock(&hugetlb_lock);
561 if (mapping)
562 hugetlb_put_quota(mapping, 1);
565 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
567 set_compound_page_dtor(page, free_huge_page);
568 spin_lock(&hugetlb_lock);
569 h->nr_huge_pages++;
570 h->nr_huge_pages_node[nid]++;
571 spin_unlock(&hugetlb_lock);
572 put_page(page); /* free it into the hugepage allocator */
575 static void prep_compound_gigantic_page(struct page *page, unsigned long order)
577 int i;
578 int nr_pages = 1 << order;
579 struct page *p = page + 1;
581 /* we rely on prep_new_huge_page to set the destructor */
582 set_compound_order(page, order);
583 __SetPageHead(page);
584 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
585 __SetPageTail(p);
586 p->first_page = page;
590 int PageHuge(struct page *page)
592 compound_page_dtor *dtor;
594 if (!PageCompound(page))
595 return 0;
597 page = compound_head(page);
598 dtor = get_compound_page_dtor(page);
600 return dtor == free_huge_page;
603 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
605 struct page *page;
607 if (h->order >= MAX_ORDER)
608 return NULL;
610 page = alloc_pages_exact_node(nid,
611 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
612 __GFP_REPEAT|__GFP_NOWARN,
613 huge_page_order(h));
614 if (page) {
615 if (arch_prepare_hugepage(page)) {
616 __free_pages(page, huge_page_order(h));
617 return NULL;
619 prep_new_huge_page(h, page, nid);
622 return page;
626 * common helper functions for hstate_next_node_to_{alloc|free}.
627 * We may have allocated or freed a huge page based on a different
628 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
629 * be outside of *nodes_allowed. Ensure that we use an allowed
630 * node for alloc or free.
632 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
634 nid = next_node(nid, *nodes_allowed);
635 if (nid == MAX_NUMNODES)
636 nid = first_node(*nodes_allowed);
637 VM_BUG_ON(nid >= MAX_NUMNODES);
639 return nid;
642 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
644 if (!node_isset(nid, *nodes_allowed))
645 nid = next_node_allowed(nid, nodes_allowed);
646 return nid;
650 * returns the previously saved node ["this node"] from which to
651 * allocate a persistent huge page for the pool and advance the
652 * next node from which to allocate, handling wrap at end of node
653 * mask.
655 static int hstate_next_node_to_alloc(struct hstate *h,
656 nodemask_t *nodes_allowed)
658 int nid;
660 VM_BUG_ON(!nodes_allowed);
662 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
663 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
665 return nid;
668 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
670 struct page *page;
671 int start_nid;
672 int next_nid;
673 int ret = 0;
675 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
676 next_nid = start_nid;
678 do {
679 page = alloc_fresh_huge_page_node(h, next_nid);
680 if (page) {
681 ret = 1;
682 break;
684 next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
685 } while (next_nid != start_nid);
687 if (ret)
688 count_vm_event(HTLB_BUDDY_PGALLOC);
689 else
690 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
692 return ret;
696 * helper for free_pool_huge_page() - return the previously saved
697 * node ["this node"] from which to free a huge page. Advance the
698 * next node id whether or not we find a free huge page to free so
699 * that the next attempt to free addresses the next node.
701 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
703 int nid;
705 VM_BUG_ON(!nodes_allowed);
707 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
708 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
710 return nid;
714 * Free huge page from pool from next node to free.
715 * Attempt to keep persistent huge pages more or less
716 * balanced over allowed nodes.
717 * Called with hugetlb_lock locked.
719 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
720 bool acct_surplus)
722 int start_nid;
723 int next_nid;
724 int ret = 0;
726 start_nid = hstate_next_node_to_free(h, nodes_allowed);
727 next_nid = start_nid;
729 do {
731 * If we're returning unused surplus pages, only examine
732 * nodes with surplus pages.
734 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
735 !list_empty(&h->hugepage_freelists[next_nid])) {
736 struct page *page =
737 list_entry(h->hugepage_freelists[next_nid].next,
738 struct page, lru);
739 list_del(&page->lru);
740 h->free_huge_pages--;
741 h->free_huge_pages_node[next_nid]--;
742 if (acct_surplus) {
743 h->surplus_huge_pages--;
744 h->surplus_huge_pages_node[next_nid]--;
746 update_and_free_page(h, page);
747 ret = 1;
748 break;
750 next_nid = hstate_next_node_to_free(h, nodes_allowed);
751 } while (next_nid != start_nid);
753 return ret;
756 static struct page *alloc_buddy_huge_page(struct hstate *h,
757 struct vm_area_struct *vma, unsigned long address)
759 struct page *page;
760 unsigned int nid;
762 if (h->order >= MAX_ORDER)
763 return NULL;
766 * Assume we will successfully allocate the surplus page to
767 * prevent racing processes from causing the surplus to exceed
768 * overcommit
770 * This however introduces a different race, where a process B
771 * tries to grow the static hugepage pool while alloc_pages() is
772 * called by process A. B will only examine the per-node
773 * counters in determining if surplus huge pages can be
774 * converted to normal huge pages in adjust_pool_surplus(). A
775 * won't be able to increment the per-node counter, until the
776 * lock is dropped by B, but B doesn't drop hugetlb_lock until
777 * no more huge pages can be converted from surplus to normal
778 * state (and doesn't try to convert again). Thus, we have a
779 * case where a surplus huge page exists, the pool is grown, and
780 * the surplus huge page still exists after, even though it
781 * should just have been converted to a normal huge page. This
782 * does not leak memory, though, as the hugepage will be freed
783 * once it is out of use. It also does not allow the counters to
784 * go out of whack in adjust_pool_surplus() as we don't modify
785 * the node values until we've gotten the hugepage and only the
786 * per-node value is checked there.
788 spin_lock(&hugetlb_lock);
789 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
790 spin_unlock(&hugetlb_lock);
791 return NULL;
792 } else {
793 h->nr_huge_pages++;
794 h->surplus_huge_pages++;
796 spin_unlock(&hugetlb_lock);
798 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
799 __GFP_REPEAT|__GFP_NOWARN,
800 huge_page_order(h));
802 if (page && arch_prepare_hugepage(page)) {
803 __free_pages(page, huge_page_order(h));
804 return NULL;
807 spin_lock(&hugetlb_lock);
808 if (page) {
810 * This page is now managed by the hugetlb allocator and has
811 * no users -- drop the buddy allocator's reference.
813 put_page_testzero(page);
814 VM_BUG_ON(page_count(page));
815 nid = page_to_nid(page);
816 set_compound_page_dtor(page, free_huge_page);
818 * We incremented the global counters already
820 h->nr_huge_pages_node[nid]++;
821 h->surplus_huge_pages_node[nid]++;
822 __count_vm_event(HTLB_BUDDY_PGALLOC);
823 } else {
824 h->nr_huge_pages--;
825 h->surplus_huge_pages--;
826 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
828 spin_unlock(&hugetlb_lock);
830 return page;
834 * Increase the hugetlb pool such that it can accomodate a reservation
835 * of size 'delta'.
837 static int gather_surplus_pages(struct hstate *h, int delta)
839 struct list_head surplus_list;
840 struct page *page, *tmp;
841 int ret, i;
842 int needed, allocated;
844 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
845 if (needed <= 0) {
846 h->resv_huge_pages += delta;
847 return 0;
850 allocated = 0;
851 INIT_LIST_HEAD(&surplus_list);
853 ret = -ENOMEM;
854 retry:
855 spin_unlock(&hugetlb_lock);
856 for (i = 0; i < needed; i++) {
857 page = alloc_buddy_huge_page(h, NULL, 0);
858 if (!page) {
860 * We were not able to allocate enough pages to
861 * satisfy the entire reservation so we free what
862 * we've allocated so far.
864 spin_lock(&hugetlb_lock);
865 needed = 0;
866 goto free;
869 list_add(&page->lru, &surplus_list);
871 allocated += needed;
874 * After retaking hugetlb_lock, we need to recalculate 'needed'
875 * because either resv_huge_pages or free_huge_pages may have changed.
877 spin_lock(&hugetlb_lock);
878 needed = (h->resv_huge_pages + delta) -
879 (h->free_huge_pages + allocated);
880 if (needed > 0)
881 goto retry;
884 * The surplus_list now contains _at_least_ the number of extra pages
885 * needed to accomodate the reservation. Add the appropriate number
886 * of pages to the hugetlb pool and free the extras back to the buddy
887 * allocator. Commit the entire reservation here to prevent another
888 * process from stealing the pages as they are added to the pool but
889 * before they are reserved.
891 needed += allocated;
892 h->resv_huge_pages += delta;
893 ret = 0;
894 free:
895 /* Free the needed pages to the hugetlb pool */
896 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
897 if ((--needed) < 0)
898 break;
899 list_del(&page->lru);
900 enqueue_huge_page(h, page);
903 /* Free unnecessary surplus pages to the buddy allocator */
904 if (!list_empty(&surplus_list)) {
905 spin_unlock(&hugetlb_lock);
906 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
907 list_del(&page->lru);
909 * The page has a reference count of zero already, so
910 * call free_huge_page directly instead of using
911 * put_page. This must be done with hugetlb_lock
912 * unlocked which is safe because free_huge_page takes
913 * hugetlb_lock before deciding how to free the page.
915 free_huge_page(page);
917 spin_lock(&hugetlb_lock);
920 return ret;
924 * When releasing a hugetlb pool reservation, any surplus pages that were
925 * allocated to satisfy the reservation must be explicitly freed if they were
926 * never used.
927 * Called with hugetlb_lock held.
929 static void return_unused_surplus_pages(struct hstate *h,
930 unsigned long unused_resv_pages)
932 unsigned long nr_pages;
934 /* Uncommit the reservation */
935 h->resv_huge_pages -= unused_resv_pages;
937 /* Cannot return gigantic pages currently */
938 if (h->order >= MAX_ORDER)
939 return;
941 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
944 * We want to release as many surplus pages as possible, spread
945 * evenly across all nodes with memory. Iterate across these nodes
946 * until we can no longer free unreserved surplus pages. This occurs
947 * when the nodes with surplus pages have no free pages.
948 * free_pool_huge_page() will balance the the freed pages across the
949 * on-line nodes with memory and will handle the hstate accounting.
951 while (nr_pages--) {
952 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
953 break;
958 * Determine if the huge page at addr within the vma has an associated
959 * reservation. Where it does not we will need to logically increase
960 * reservation and actually increase quota before an allocation can occur.
961 * Where any new reservation would be required the reservation change is
962 * prepared, but not committed. Once the page has been quota'd allocated
963 * an instantiated the change should be committed via vma_commit_reservation.
964 * No action is required on failure.
966 static long vma_needs_reservation(struct hstate *h,
967 struct vm_area_struct *vma, unsigned long addr)
969 struct address_space *mapping = vma->vm_file->f_mapping;
970 struct inode *inode = mapping->host;
972 if (vma->vm_flags & VM_MAYSHARE) {
973 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
974 return region_chg(&inode->i_mapping->private_list,
975 idx, idx + 1);
977 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
978 return 1;
980 } else {
981 long err;
982 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
983 struct resv_map *reservations = vma_resv_map(vma);
985 err = region_chg(&reservations->regions, idx, idx + 1);
986 if (err < 0)
987 return err;
988 return 0;
991 static void vma_commit_reservation(struct hstate *h,
992 struct vm_area_struct *vma, unsigned long addr)
994 struct address_space *mapping = vma->vm_file->f_mapping;
995 struct inode *inode = mapping->host;
997 if (vma->vm_flags & VM_MAYSHARE) {
998 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
999 region_add(&inode->i_mapping->private_list, idx, idx + 1);
1001 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1002 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1003 struct resv_map *reservations = vma_resv_map(vma);
1005 /* Mark this page used in the map. */
1006 region_add(&reservations->regions, idx, idx + 1);
1010 static struct page *alloc_huge_page(struct vm_area_struct *vma,
1011 unsigned long addr, int avoid_reserve)
1013 struct hstate *h = hstate_vma(vma);
1014 struct page *page;
1015 struct address_space *mapping = vma->vm_file->f_mapping;
1016 struct inode *inode = mapping->host;
1017 long chg;
1020 * Processes that did not create the mapping will have no reserves and
1021 * will not have accounted against quota. Check that the quota can be
1022 * made before satisfying the allocation
1023 * MAP_NORESERVE mappings may also need pages and quota allocated
1024 * if no reserve mapping overlaps.
1026 chg = vma_needs_reservation(h, vma, addr);
1027 if (chg < 0)
1028 return ERR_PTR(chg);
1029 if (chg)
1030 if (hugetlb_get_quota(inode->i_mapping, chg))
1031 return ERR_PTR(-ENOSPC);
1033 spin_lock(&hugetlb_lock);
1034 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1035 spin_unlock(&hugetlb_lock);
1037 if (!page) {
1038 page = alloc_buddy_huge_page(h, vma, addr);
1039 if (!page) {
1040 hugetlb_put_quota(inode->i_mapping, chg);
1041 return ERR_PTR(-VM_FAULT_OOM);
1045 set_page_refcounted(page);
1046 set_page_private(page, (unsigned long) mapping);
1048 vma_commit_reservation(h, vma, addr);
1050 return page;
1053 int __weak alloc_bootmem_huge_page(struct hstate *h)
1055 struct huge_bootmem_page *m;
1056 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1058 while (nr_nodes) {
1059 void *addr;
1061 addr = __alloc_bootmem_node_nopanic(
1062 NODE_DATA(hstate_next_node_to_alloc(h,
1063 &node_states[N_HIGH_MEMORY])),
1064 huge_page_size(h), huge_page_size(h), 0);
1066 if (addr) {
1068 * Use the beginning of the huge page to store the
1069 * huge_bootmem_page struct (until gather_bootmem
1070 * puts them into the mem_map).
1072 m = addr;
1073 goto found;
1075 nr_nodes--;
1077 return 0;
1079 found:
1080 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1081 /* Put them into a private list first because mem_map is not up yet */
1082 list_add(&m->list, &huge_boot_pages);
1083 m->hstate = h;
1084 return 1;
1087 static void prep_compound_huge_page(struct page *page, int order)
1089 if (unlikely(order > (MAX_ORDER - 1)))
1090 prep_compound_gigantic_page(page, order);
1091 else
1092 prep_compound_page(page, order);
1095 /* Put bootmem huge pages into the standard lists after mem_map is up */
1096 static void __init gather_bootmem_prealloc(void)
1098 struct huge_bootmem_page *m;
1100 list_for_each_entry(m, &huge_boot_pages, list) {
1101 struct page *page = virt_to_page(m);
1102 struct hstate *h = m->hstate;
1103 __ClearPageReserved(page);
1104 WARN_ON(page_count(page) != 1);
1105 prep_compound_huge_page(page, h->order);
1106 prep_new_huge_page(h, page, page_to_nid(page));
1110 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1112 unsigned long i;
1114 for (i = 0; i < h->max_huge_pages; ++i) {
1115 if (h->order >= MAX_ORDER) {
1116 if (!alloc_bootmem_huge_page(h))
1117 break;
1118 } else if (!alloc_fresh_huge_page(h,
1119 &node_states[N_HIGH_MEMORY]))
1120 break;
1122 h->max_huge_pages = i;
1125 static void __init hugetlb_init_hstates(void)
1127 struct hstate *h;
1129 for_each_hstate(h) {
1130 /* oversize hugepages were init'ed in early boot */
1131 if (h->order < MAX_ORDER)
1132 hugetlb_hstate_alloc_pages(h);
1136 static char * __init memfmt(char *buf, unsigned long n)
1138 if (n >= (1UL << 30))
1139 sprintf(buf, "%lu GB", n >> 30);
1140 else if (n >= (1UL << 20))
1141 sprintf(buf, "%lu MB", n >> 20);
1142 else
1143 sprintf(buf, "%lu KB", n >> 10);
1144 return buf;
1147 static void __init report_hugepages(void)
1149 struct hstate *h;
1151 for_each_hstate(h) {
1152 char buf[32];
1153 printk(KERN_INFO "HugeTLB registered %s page size, "
1154 "pre-allocated %ld pages\n",
1155 memfmt(buf, huge_page_size(h)),
1156 h->free_huge_pages);
1160 #ifdef CONFIG_HIGHMEM
1161 static void try_to_free_low(struct hstate *h, unsigned long count,
1162 nodemask_t *nodes_allowed)
1164 int i;
1166 if (h->order >= MAX_ORDER)
1167 return;
1169 for_each_node_mask(i, *nodes_allowed) {
1170 struct page *page, *next;
1171 struct list_head *freel = &h->hugepage_freelists[i];
1172 list_for_each_entry_safe(page, next, freel, lru) {
1173 if (count >= h->nr_huge_pages)
1174 return;
1175 if (PageHighMem(page))
1176 continue;
1177 list_del(&page->lru);
1178 update_and_free_page(h, page);
1179 h->free_huge_pages--;
1180 h->free_huge_pages_node[page_to_nid(page)]--;
1184 #else
1185 static inline void try_to_free_low(struct hstate *h, unsigned long count,
1186 nodemask_t *nodes_allowed)
1189 #endif
1192 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1193 * balanced by operating on them in a round-robin fashion.
1194 * Returns 1 if an adjustment was made.
1196 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1197 int delta)
1199 int start_nid, next_nid;
1200 int ret = 0;
1202 VM_BUG_ON(delta != -1 && delta != 1);
1204 if (delta < 0)
1205 start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1206 else
1207 start_nid = hstate_next_node_to_free(h, nodes_allowed);
1208 next_nid = start_nid;
1210 do {
1211 int nid = next_nid;
1212 if (delta < 0) {
1214 * To shrink on this node, there must be a surplus page
1216 if (!h->surplus_huge_pages_node[nid]) {
1217 next_nid = hstate_next_node_to_alloc(h,
1218 nodes_allowed);
1219 continue;
1222 if (delta > 0) {
1224 * Surplus cannot exceed the total number of pages
1226 if (h->surplus_huge_pages_node[nid] >=
1227 h->nr_huge_pages_node[nid]) {
1228 next_nid = hstate_next_node_to_free(h,
1229 nodes_allowed);
1230 continue;
1234 h->surplus_huge_pages += delta;
1235 h->surplus_huge_pages_node[nid] += delta;
1236 ret = 1;
1237 break;
1238 } while (next_nid != start_nid);
1240 return ret;
1243 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1244 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1245 nodemask_t *nodes_allowed)
1247 unsigned long min_count, ret;
1249 if (h->order >= MAX_ORDER)
1250 return h->max_huge_pages;
1253 * Increase the pool size
1254 * First take pages out of surplus state. Then make up the
1255 * remaining difference by allocating fresh huge pages.
1257 * We might race with alloc_buddy_huge_page() here and be unable
1258 * to convert a surplus huge page to a normal huge page. That is
1259 * not critical, though, it just means the overall size of the
1260 * pool might be one hugepage larger than it needs to be, but
1261 * within all the constraints specified by the sysctls.
1263 spin_lock(&hugetlb_lock);
1264 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1265 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1266 break;
1269 while (count > persistent_huge_pages(h)) {
1271 * If this allocation races such that we no longer need the
1272 * page, free_huge_page will handle it by freeing the page
1273 * and reducing the surplus.
1275 spin_unlock(&hugetlb_lock);
1276 ret = alloc_fresh_huge_page(h, nodes_allowed);
1277 spin_lock(&hugetlb_lock);
1278 if (!ret)
1279 goto out;
1281 /* Bail for signals. Probably ctrl-c from user */
1282 if (signal_pending(current))
1283 goto out;
1287 * Decrease the pool size
1288 * First return free pages to the buddy allocator (being careful
1289 * to keep enough around to satisfy reservations). Then place
1290 * pages into surplus state as needed so the pool will shrink
1291 * to the desired size as pages become free.
1293 * By placing pages into the surplus state independent of the
1294 * overcommit value, we are allowing the surplus pool size to
1295 * exceed overcommit. There are few sane options here. Since
1296 * alloc_buddy_huge_page() is checking the global counter,
1297 * though, we'll note that we're not allowed to exceed surplus
1298 * and won't grow the pool anywhere else. Not until one of the
1299 * sysctls are changed, or the surplus pages go out of use.
1301 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1302 min_count = max(count, min_count);
1303 try_to_free_low(h, min_count, nodes_allowed);
1304 while (min_count < persistent_huge_pages(h)) {
1305 if (!free_pool_huge_page(h, nodes_allowed, 0))
1306 break;
1308 while (count < persistent_huge_pages(h)) {
1309 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1310 break;
1312 out:
1313 ret = persistent_huge_pages(h);
1314 spin_unlock(&hugetlb_lock);
1315 return ret;
1318 #define HSTATE_ATTR_RO(_name) \
1319 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1321 #define HSTATE_ATTR(_name) \
1322 static struct kobj_attribute _name##_attr = \
1323 __ATTR(_name, 0644, _name##_show, _name##_store)
1325 static struct kobject *hugepages_kobj;
1326 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1328 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1330 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1332 int i;
1334 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1335 if (hstate_kobjs[i] == kobj) {
1336 if (nidp)
1337 *nidp = NUMA_NO_NODE;
1338 return &hstates[i];
1341 return kobj_to_node_hstate(kobj, nidp);
1344 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1345 struct kobj_attribute *attr, char *buf)
1347 struct hstate *h;
1348 unsigned long nr_huge_pages;
1349 int nid;
1351 h = kobj_to_hstate(kobj, &nid);
1352 if (nid == NUMA_NO_NODE)
1353 nr_huge_pages = h->nr_huge_pages;
1354 else
1355 nr_huge_pages = h->nr_huge_pages_node[nid];
1357 return sprintf(buf, "%lu\n", nr_huge_pages);
1359 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1360 struct kobject *kobj, struct kobj_attribute *attr,
1361 const char *buf, size_t len)
1363 int err;
1364 int nid;
1365 unsigned long count;
1366 struct hstate *h;
1367 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1369 err = strict_strtoul(buf, 10, &count);
1370 if (err)
1371 return 0;
1373 h = kobj_to_hstate(kobj, &nid);
1374 if (nid == NUMA_NO_NODE) {
1376 * global hstate attribute
1378 if (!(obey_mempolicy &&
1379 init_nodemask_of_mempolicy(nodes_allowed))) {
1380 NODEMASK_FREE(nodes_allowed);
1381 nodes_allowed = &node_states[N_HIGH_MEMORY];
1383 } else if (nodes_allowed) {
1385 * per node hstate attribute: adjust count to global,
1386 * but restrict alloc/free to the specified node.
1388 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1389 init_nodemask_of_node(nodes_allowed, nid);
1390 } else
1391 nodes_allowed = &node_states[N_HIGH_MEMORY];
1393 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1395 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1396 NODEMASK_FREE(nodes_allowed);
1398 return len;
1401 static ssize_t nr_hugepages_show(struct kobject *kobj,
1402 struct kobj_attribute *attr, char *buf)
1404 return nr_hugepages_show_common(kobj, attr, buf);
1407 static ssize_t nr_hugepages_store(struct kobject *kobj,
1408 struct kobj_attribute *attr, const char *buf, size_t len)
1410 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1412 HSTATE_ATTR(nr_hugepages);
1414 #ifdef CONFIG_NUMA
1417 * hstate attribute for optionally mempolicy-based constraint on persistent
1418 * huge page alloc/free.
1420 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1421 struct kobj_attribute *attr, char *buf)
1423 return nr_hugepages_show_common(kobj, attr, buf);
1426 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1427 struct kobj_attribute *attr, const char *buf, size_t len)
1429 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1431 HSTATE_ATTR(nr_hugepages_mempolicy);
1432 #endif
1435 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1436 struct kobj_attribute *attr, char *buf)
1438 struct hstate *h = kobj_to_hstate(kobj, NULL);
1439 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1441 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1442 struct kobj_attribute *attr, const char *buf, size_t count)
1444 int err;
1445 unsigned long input;
1446 struct hstate *h = kobj_to_hstate(kobj, NULL);
1448 err = strict_strtoul(buf, 10, &input);
1449 if (err)
1450 return 0;
1452 spin_lock(&hugetlb_lock);
1453 h->nr_overcommit_huge_pages = input;
1454 spin_unlock(&hugetlb_lock);
1456 return count;
1458 HSTATE_ATTR(nr_overcommit_hugepages);
1460 static ssize_t free_hugepages_show(struct kobject *kobj,
1461 struct kobj_attribute *attr, char *buf)
1463 struct hstate *h;
1464 unsigned long free_huge_pages;
1465 int nid;
1467 h = kobj_to_hstate(kobj, &nid);
1468 if (nid == NUMA_NO_NODE)
1469 free_huge_pages = h->free_huge_pages;
1470 else
1471 free_huge_pages = h->free_huge_pages_node[nid];
1473 return sprintf(buf, "%lu\n", free_huge_pages);
1475 HSTATE_ATTR_RO(free_hugepages);
1477 static ssize_t resv_hugepages_show(struct kobject *kobj,
1478 struct kobj_attribute *attr, char *buf)
1480 struct hstate *h = kobj_to_hstate(kobj, NULL);
1481 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1483 HSTATE_ATTR_RO(resv_hugepages);
1485 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1486 struct kobj_attribute *attr, char *buf)
1488 struct hstate *h;
1489 unsigned long surplus_huge_pages;
1490 int nid;
1492 h = kobj_to_hstate(kobj, &nid);
1493 if (nid == NUMA_NO_NODE)
1494 surplus_huge_pages = h->surplus_huge_pages;
1495 else
1496 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1498 return sprintf(buf, "%lu\n", surplus_huge_pages);
1500 HSTATE_ATTR_RO(surplus_hugepages);
1502 static struct attribute *hstate_attrs[] = {
1503 &nr_hugepages_attr.attr,
1504 &nr_overcommit_hugepages_attr.attr,
1505 &free_hugepages_attr.attr,
1506 &resv_hugepages_attr.attr,
1507 &surplus_hugepages_attr.attr,
1508 #ifdef CONFIG_NUMA
1509 &nr_hugepages_mempolicy_attr.attr,
1510 #endif
1511 NULL,
1514 static struct attribute_group hstate_attr_group = {
1515 .attrs = hstate_attrs,
1518 static int __init hugetlb_sysfs_add_hstate(struct hstate *h,
1519 struct kobject *parent,
1520 struct kobject **hstate_kobjs,
1521 struct attribute_group *hstate_attr_group)
1523 int retval;
1524 int hi = h - hstates;
1526 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1527 if (!hstate_kobjs[hi])
1528 return -ENOMEM;
1530 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1531 if (retval)
1532 kobject_put(hstate_kobjs[hi]);
1534 return retval;
1537 static void __init hugetlb_sysfs_init(void)
1539 struct hstate *h;
1540 int err;
1542 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1543 if (!hugepages_kobj)
1544 return;
1546 for_each_hstate(h) {
1547 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1548 hstate_kobjs, &hstate_attr_group);
1549 if (err)
1550 printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1551 h->name);
1555 #ifdef CONFIG_NUMA
1558 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1559 * with node sysdevs in node_devices[] using a parallel array. The array
1560 * index of a node sysdev or _hstate == node id.
1561 * This is here to avoid any static dependency of the node sysdev driver, in
1562 * the base kernel, on the hugetlb module.
1564 struct node_hstate {
1565 struct kobject *hugepages_kobj;
1566 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1568 struct node_hstate node_hstates[MAX_NUMNODES];
1571 * A subset of global hstate attributes for node sysdevs
1573 static struct attribute *per_node_hstate_attrs[] = {
1574 &nr_hugepages_attr.attr,
1575 &free_hugepages_attr.attr,
1576 &surplus_hugepages_attr.attr,
1577 NULL,
1580 static struct attribute_group per_node_hstate_attr_group = {
1581 .attrs = per_node_hstate_attrs,
1585 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1586 * Returns node id via non-NULL nidp.
1588 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1590 int nid;
1592 for (nid = 0; nid < nr_node_ids; nid++) {
1593 struct node_hstate *nhs = &node_hstates[nid];
1594 int i;
1595 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1596 if (nhs->hstate_kobjs[i] == kobj) {
1597 if (nidp)
1598 *nidp = nid;
1599 return &hstates[i];
1603 BUG();
1604 return NULL;
1608 * Unregister hstate attributes from a single node sysdev.
1609 * No-op if no hstate attributes attached.
1611 void hugetlb_unregister_node(struct node *node)
1613 struct hstate *h;
1614 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1616 if (!nhs->hugepages_kobj)
1617 return; /* no hstate attributes */
1619 for_each_hstate(h)
1620 if (nhs->hstate_kobjs[h - hstates]) {
1621 kobject_put(nhs->hstate_kobjs[h - hstates]);
1622 nhs->hstate_kobjs[h - hstates] = NULL;
1625 kobject_put(nhs->hugepages_kobj);
1626 nhs->hugepages_kobj = NULL;
1630 * hugetlb module exit: unregister hstate attributes from node sysdevs
1631 * that have them.
1633 static void hugetlb_unregister_all_nodes(void)
1635 int nid;
1638 * disable node sysdev registrations.
1640 register_hugetlbfs_with_node(NULL, NULL);
1643 * remove hstate attributes from any nodes that have them.
1645 for (nid = 0; nid < nr_node_ids; nid++)
1646 hugetlb_unregister_node(&node_devices[nid]);
1650 * Register hstate attributes for a single node sysdev.
1651 * No-op if attributes already registered.
1653 void hugetlb_register_node(struct node *node)
1655 struct hstate *h;
1656 struct node_hstate *nhs = &node_hstates[node->sysdev.id];
1657 int err;
1659 if (nhs->hugepages_kobj)
1660 return; /* already allocated */
1662 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1663 &node->sysdev.kobj);
1664 if (!nhs->hugepages_kobj)
1665 return;
1667 for_each_hstate(h) {
1668 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1669 nhs->hstate_kobjs,
1670 &per_node_hstate_attr_group);
1671 if (err) {
1672 printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
1673 " for node %d\n",
1674 h->name, node->sysdev.id);
1675 hugetlb_unregister_node(node);
1676 break;
1682 * hugetlb init time: register hstate attributes for all registered node
1683 * sysdevs of nodes that have memory. All on-line nodes should have
1684 * registered their associated sysdev by this time.
1686 static void hugetlb_register_all_nodes(void)
1688 int nid;
1690 for_each_node_state(nid, N_HIGH_MEMORY) {
1691 struct node *node = &node_devices[nid];
1692 if (node->sysdev.id == nid)
1693 hugetlb_register_node(node);
1697 * Let the node sysdev driver know we're here so it can
1698 * [un]register hstate attributes on node hotplug.
1700 register_hugetlbfs_with_node(hugetlb_register_node,
1701 hugetlb_unregister_node);
1703 #else /* !CONFIG_NUMA */
1705 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1707 BUG();
1708 if (nidp)
1709 *nidp = -1;
1710 return NULL;
1713 static void hugetlb_unregister_all_nodes(void) { }
1715 static void hugetlb_register_all_nodes(void) { }
1717 #endif
1719 static void __exit hugetlb_exit(void)
1721 struct hstate *h;
1723 hugetlb_unregister_all_nodes();
1725 for_each_hstate(h) {
1726 kobject_put(hstate_kobjs[h - hstates]);
1729 kobject_put(hugepages_kobj);
1731 module_exit(hugetlb_exit);
1733 static int __init hugetlb_init(void)
1735 /* Some platform decide whether they support huge pages at boot
1736 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1737 * there is no such support
1739 if (HPAGE_SHIFT == 0)
1740 return 0;
1742 if (!size_to_hstate(default_hstate_size)) {
1743 default_hstate_size = HPAGE_SIZE;
1744 if (!size_to_hstate(default_hstate_size))
1745 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1747 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
1748 if (default_hstate_max_huge_pages)
1749 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1751 hugetlb_init_hstates();
1753 gather_bootmem_prealloc();
1755 report_hugepages();
1757 hugetlb_sysfs_init();
1759 hugetlb_register_all_nodes();
1761 return 0;
1763 module_init(hugetlb_init);
1765 /* Should be called on processing a hugepagesz=... option */
1766 void __init hugetlb_add_hstate(unsigned order)
1768 struct hstate *h;
1769 unsigned long i;
1771 if (size_to_hstate(PAGE_SIZE << order)) {
1772 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1773 return;
1775 BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1776 BUG_ON(order == 0);
1777 h = &hstates[max_hstate++];
1778 h->order = order;
1779 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1780 h->nr_huge_pages = 0;
1781 h->free_huge_pages = 0;
1782 for (i = 0; i < MAX_NUMNODES; ++i)
1783 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1784 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
1785 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1786 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1787 huge_page_size(h)/1024);
1789 parsed_hstate = h;
1792 static int __init hugetlb_nrpages_setup(char *s)
1794 unsigned long *mhp;
1795 static unsigned long *last_mhp;
1798 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1799 * so this hugepages= parameter goes to the "default hstate".
1801 if (!max_hstate)
1802 mhp = &default_hstate_max_huge_pages;
1803 else
1804 mhp = &parsed_hstate->max_huge_pages;
1806 if (mhp == last_mhp) {
1807 printk(KERN_WARNING "hugepages= specified twice without "
1808 "interleaving hugepagesz=, ignoring\n");
1809 return 1;
1812 if (sscanf(s, "%lu", mhp) <= 0)
1813 *mhp = 0;
1816 * Global state is always initialized later in hugetlb_init.
1817 * But we need to allocate >= MAX_ORDER hstates here early to still
1818 * use the bootmem allocator.
1820 if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1821 hugetlb_hstate_alloc_pages(parsed_hstate);
1823 last_mhp = mhp;
1825 return 1;
1827 __setup("hugepages=", hugetlb_nrpages_setup);
1829 static int __init hugetlb_default_setup(char *s)
1831 default_hstate_size = memparse(s, &s);
1832 return 1;
1834 __setup("default_hugepagesz=", hugetlb_default_setup);
1836 static unsigned int cpuset_mems_nr(unsigned int *array)
1838 int node;
1839 unsigned int nr = 0;
1841 for_each_node_mask(node, cpuset_current_mems_allowed)
1842 nr += array[node];
1844 return nr;
1847 #ifdef CONFIG_SYSCTL
1848 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
1849 struct ctl_table *table, int write,
1850 void __user *buffer, size_t *length, loff_t *ppos)
1852 struct hstate *h = &default_hstate;
1853 unsigned long tmp;
1855 if (!write)
1856 tmp = h->max_huge_pages;
1858 table->data = &tmp;
1859 table->maxlen = sizeof(unsigned long);
1860 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1862 if (write) {
1863 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
1864 GFP_KERNEL | __GFP_NORETRY);
1865 if (!(obey_mempolicy &&
1866 init_nodemask_of_mempolicy(nodes_allowed))) {
1867 NODEMASK_FREE(nodes_allowed);
1868 nodes_allowed = &node_states[N_HIGH_MEMORY];
1870 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
1872 if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1873 NODEMASK_FREE(nodes_allowed);
1876 return 0;
1879 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1880 void __user *buffer, size_t *length, loff_t *ppos)
1883 return hugetlb_sysctl_handler_common(false, table, write,
1884 buffer, length, ppos);
1887 #ifdef CONFIG_NUMA
1888 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
1889 void __user *buffer, size_t *length, loff_t *ppos)
1891 return hugetlb_sysctl_handler_common(true, table, write,
1892 buffer, length, ppos);
1894 #endif /* CONFIG_NUMA */
1896 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1897 void __user *buffer,
1898 size_t *length, loff_t *ppos)
1900 proc_dointvec(table, write, buffer, length, ppos);
1901 if (hugepages_treat_as_movable)
1902 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1903 else
1904 htlb_alloc_mask = GFP_HIGHUSER;
1905 return 0;
1908 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1909 void __user *buffer,
1910 size_t *length, loff_t *ppos)
1912 struct hstate *h = &default_hstate;
1913 unsigned long tmp;
1915 if (!write)
1916 tmp = h->nr_overcommit_huge_pages;
1918 table->data = &tmp;
1919 table->maxlen = sizeof(unsigned long);
1920 proc_doulongvec_minmax(table, write, buffer, length, ppos);
1922 if (write) {
1923 spin_lock(&hugetlb_lock);
1924 h->nr_overcommit_huge_pages = tmp;
1925 spin_unlock(&hugetlb_lock);
1928 return 0;
1931 #endif /* CONFIG_SYSCTL */
1933 void hugetlb_report_meminfo(struct seq_file *m)
1935 struct hstate *h = &default_hstate;
1936 seq_printf(m,
1937 "HugePages_Total: %5lu\n"
1938 "HugePages_Free: %5lu\n"
1939 "HugePages_Rsvd: %5lu\n"
1940 "HugePages_Surp: %5lu\n"
1941 "Hugepagesize: %8lu kB\n",
1942 h->nr_huge_pages,
1943 h->free_huge_pages,
1944 h->resv_huge_pages,
1945 h->surplus_huge_pages,
1946 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1949 int hugetlb_report_node_meminfo(int nid, char *buf)
1951 struct hstate *h = &default_hstate;
1952 return sprintf(buf,
1953 "Node %d HugePages_Total: %5u\n"
1954 "Node %d HugePages_Free: %5u\n"
1955 "Node %d HugePages_Surp: %5u\n",
1956 nid, h->nr_huge_pages_node[nid],
1957 nid, h->free_huge_pages_node[nid],
1958 nid, h->surplus_huge_pages_node[nid]);
1961 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1962 unsigned long hugetlb_total_pages(void)
1964 struct hstate *h = &default_hstate;
1965 return h->nr_huge_pages * pages_per_huge_page(h);
1968 static int hugetlb_acct_memory(struct hstate *h, long delta)
1970 int ret = -ENOMEM;
1972 spin_lock(&hugetlb_lock);
1974 * When cpuset is configured, it breaks the strict hugetlb page
1975 * reservation as the accounting is done on a global variable. Such
1976 * reservation is completely rubbish in the presence of cpuset because
1977 * the reservation is not checked against page availability for the
1978 * current cpuset. Application can still potentially OOM'ed by kernel
1979 * with lack of free htlb page in cpuset that the task is in.
1980 * Attempt to enforce strict accounting with cpuset is almost
1981 * impossible (or too ugly) because cpuset is too fluid that
1982 * task or memory node can be dynamically moved between cpusets.
1984 * The change of semantics for shared hugetlb mapping with cpuset is
1985 * undesirable. However, in order to preserve some of the semantics,
1986 * we fall back to check against current free page availability as
1987 * a best attempt and hopefully to minimize the impact of changing
1988 * semantics that cpuset has.
1990 if (delta > 0) {
1991 if (gather_surplus_pages(h, delta) < 0)
1992 goto out;
1994 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1995 return_unused_surplus_pages(h, delta);
1996 goto out;
2000 ret = 0;
2001 if (delta < 0)
2002 return_unused_surplus_pages(h, (unsigned long) -delta);
2004 out:
2005 spin_unlock(&hugetlb_lock);
2006 return ret;
2009 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2011 struct resv_map *reservations = vma_resv_map(vma);
2014 * This new VMA should share its siblings reservation map if present.
2015 * The VMA will only ever have a valid reservation map pointer where
2016 * it is being copied for another still existing VMA. As that VMA
2017 * has a reference to the reservation map it cannot dissappear until
2018 * after this open call completes. It is therefore safe to take a
2019 * new reference here without additional locking.
2021 if (reservations)
2022 kref_get(&reservations->refs);
2025 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2027 struct hstate *h = hstate_vma(vma);
2028 struct resv_map *reservations = vma_resv_map(vma);
2029 unsigned long reserve;
2030 unsigned long start;
2031 unsigned long end;
2033 if (reservations) {
2034 start = vma_hugecache_offset(h, vma, vma->vm_start);
2035 end = vma_hugecache_offset(h, vma, vma->vm_end);
2037 reserve = (end - start) -
2038 region_count(&reservations->regions, start, end);
2040 kref_put(&reservations->refs, resv_map_release);
2042 if (reserve) {
2043 hugetlb_acct_memory(h, -reserve);
2044 hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
2050 * We cannot handle pagefaults against hugetlb pages at all. They cause
2051 * handle_mm_fault() to try to instantiate regular-sized pages in the
2052 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2053 * this far.
2055 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2057 BUG();
2058 return 0;
2061 const struct vm_operations_struct hugetlb_vm_ops = {
2062 .fault = hugetlb_vm_op_fault,
2063 .open = hugetlb_vm_op_open,
2064 .close = hugetlb_vm_op_close,
2067 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2068 int writable)
2070 pte_t entry;
2072 if (writable) {
2073 entry =
2074 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
2075 } else {
2076 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
2078 entry = pte_mkyoung(entry);
2079 entry = pte_mkhuge(entry);
2081 return entry;
2084 static void set_huge_ptep_writable(struct vm_area_struct *vma,
2085 unsigned long address, pte_t *ptep)
2087 pte_t entry;
2089 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2090 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
2091 update_mmu_cache(vma, address, entry);
2096 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2097 struct vm_area_struct *vma)
2099 pte_t *src_pte, *dst_pte, entry;
2100 struct page *ptepage;
2101 unsigned long addr;
2102 int cow;
2103 struct hstate *h = hstate_vma(vma);
2104 unsigned long sz = huge_page_size(h);
2106 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2108 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2109 src_pte = huge_pte_offset(src, addr);
2110 if (!src_pte)
2111 continue;
2112 dst_pte = huge_pte_alloc(dst, addr, sz);
2113 if (!dst_pte)
2114 goto nomem;
2116 /* If the pagetables are shared don't copy or take references */
2117 if (dst_pte == src_pte)
2118 continue;
2120 spin_lock(&dst->page_table_lock);
2121 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2122 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2123 if (cow)
2124 huge_ptep_set_wrprotect(src, addr, src_pte);
2125 entry = huge_ptep_get(src_pte);
2126 ptepage = pte_page(entry);
2127 get_page(ptepage);
2128 set_huge_pte_at(dst, addr, dst_pte, entry);
2130 spin_unlock(&src->page_table_lock);
2131 spin_unlock(&dst->page_table_lock);
2133 return 0;
2135 nomem:
2136 return -ENOMEM;
2139 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2140 unsigned long end, struct page *ref_page)
2142 struct mm_struct *mm = vma->vm_mm;
2143 unsigned long address;
2144 pte_t *ptep;
2145 pte_t pte;
2146 struct page *page;
2147 struct page *tmp;
2148 struct hstate *h = hstate_vma(vma);
2149 unsigned long sz = huge_page_size(h);
2152 * A page gathering list, protected by per file i_mmap_lock. The
2153 * lock is used to avoid list corruption from multiple unmapping
2154 * of the same page since we are using page->lru.
2156 LIST_HEAD(page_list);
2158 WARN_ON(!is_vm_hugetlb_page(vma));
2159 BUG_ON(start & ~huge_page_mask(h));
2160 BUG_ON(end & ~huge_page_mask(h));
2162 mmu_notifier_invalidate_range_start(mm, start, end);
2163 spin_lock(&mm->page_table_lock);
2164 for (address = start; address < end; address += sz) {
2165 ptep = huge_pte_offset(mm, address);
2166 if (!ptep)
2167 continue;
2169 if (huge_pmd_unshare(mm, &address, ptep))
2170 continue;
2173 * If a reference page is supplied, it is because a specific
2174 * page is being unmapped, not a range. Ensure the page we
2175 * are about to unmap is the actual page of interest.
2177 if (ref_page) {
2178 pte = huge_ptep_get(ptep);
2179 if (huge_pte_none(pte))
2180 continue;
2181 page = pte_page(pte);
2182 if (page != ref_page)
2183 continue;
2186 * Mark the VMA as having unmapped its page so that
2187 * future faults in this VMA will fail rather than
2188 * looking like data was lost
2190 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2193 pte = huge_ptep_get_and_clear(mm, address, ptep);
2194 if (huge_pte_none(pte))
2195 continue;
2197 page = pte_page(pte);
2198 if (pte_dirty(pte))
2199 set_page_dirty(page);
2200 list_add(&page->lru, &page_list);
2202 spin_unlock(&mm->page_table_lock);
2203 flush_tlb_range(vma, start, end);
2204 mmu_notifier_invalidate_range_end(mm, start, end);
2205 list_for_each_entry_safe(page, tmp, &page_list, lru) {
2206 list_del(&page->lru);
2207 put_page(page);
2211 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2212 unsigned long end, struct page *ref_page)
2214 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2215 __unmap_hugepage_range(vma, start, end, ref_page);
2216 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2220 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2221 * mappping it owns the reserve page for. The intention is to unmap the page
2222 * from other VMAs and let the children be SIGKILLed if they are faulting the
2223 * same region.
2225 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2226 struct page *page, unsigned long address)
2228 struct hstate *h = hstate_vma(vma);
2229 struct vm_area_struct *iter_vma;
2230 struct address_space *mapping;
2231 struct prio_tree_iter iter;
2232 pgoff_t pgoff;
2235 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2236 * from page cache lookup which is in HPAGE_SIZE units.
2238 address = address & huge_page_mask(h);
2239 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
2240 + (vma->vm_pgoff >> PAGE_SHIFT);
2241 mapping = (struct address_space *)page_private(page);
2244 * Take the mapping lock for the duration of the table walk. As
2245 * this mapping should be shared between all the VMAs,
2246 * __unmap_hugepage_range() is called as the lock is already held
2248 spin_lock(&mapping->i_mmap_lock);
2249 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
2250 /* Do not unmap the current VMA */
2251 if (iter_vma == vma)
2252 continue;
2255 * Unmap the page from other VMAs without their own reserves.
2256 * They get marked to be SIGKILLed if they fault in these
2257 * areas. This is because a future no-page fault on this VMA
2258 * could insert a zeroed page instead of the data existing
2259 * from the time of fork. This would look like data corruption
2261 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2262 __unmap_hugepage_range(iter_vma,
2263 address, address + huge_page_size(h),
2264 page);
2266 spin_unlock(&mapping->i_mmap_lock);
2268 return 1;
2271 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2272 unsigned long address, pte_t *ptep, pte_t pte,
2273 struct page *pagecache_page)
2275 struct hstate *h = hstate_vma(vma);
2276 struct page *old_page, *new_page;
2277 int avoidcopy;
2278 int outside_reserve = 0;
2280 old_page = pte_page(pte);
2282 retry_avoidcopy:
2283 /* If no-one else is actually using this page, avoid the copy
2284 * and just make the page writable */
2285 avoidcopy = (page_count(old_page) == 1);
2286 if (avoidcopy) {
2287 set_huge_ptep_writable(vma, address, ptep);
2288 return 0;
2292 * If the process that created a MAP_PRIVATE mapping is about to
2293 * perform a COW due to a shared page count, attempt to satisfy
2294 * the allocation without using the existing reserves. The pagecache
2295 * page is used to determine if the reserve at this address was
2296 * consumed or not. If reserves were used, a partial faulted mapping
2297 * at the time of fork() could consume its reserves on COW instead
2298 * of the full address range.
2300 if (!(vma->vm_flags & VM_MAYSHARE) &&
2301 is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2302 old_page != pagecache_page)
2303 outside_reserve = 1;
2305 page_cache_get(old_page);
2307 /* Drop page_table_lock as buddy allocator may be called */
2308 spin_unlock(&mm->page_table_lock);
2309 new_page = alloc_huge_page(vma, address, outside_reserve);
2311 if (IS_ERR(new_page)) {
2312 page_cache_release(old_page);
2315 * If a process owning a MAP_PRIVATE mapping fails to COW,
2316 * it is due to references held by a child and an insufficient
2317 * huge page pool. To guarantee the original mappers
2318 * reliability, unmap the page from child processes. The child
2319 * may get SIGKILLed if it later faults.
2321 if (outside_reserve) {
2322 BUG_ON(huge_pte_none(pte));
2323 if (unmap_ref_private(mm, vma, old_page, address)) {
2324 BUG_ON(page_count(old_page) != 1);
2325 BUG_ON(huge_pte_none(pte));
2326 spin_lock(&mm->page_table_lock);
2327 goto retry_avoidcopy;
2329 WARN_ON_ONCE(1);
2332 /* Caller expects lock to be held */
2333 spin_lock(&mm->page_table_lock);
2334 return -PTR_ERR(new_page);
2337 copy_huge_page(new_page, old_page, address, vma);
2338 __SetPageUptodate(new_page);
2341 * Retake the page_table_lock to check for racing updates
2342 * before the page tables are altered
2344 spin_lock(&mm->page_table_lock);
2345 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2346 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2347 /* Break COW */
2348 huge_ptep_clear_flush(vma, address, ptep);
2349 set_huge_pte_at(mm, address, ptep,
2350 make_huge_pte(vma, new_page, 1));
2351 /* Make the old page be freed below */
2352 new_page = old_page;
2354 page_cache_release(new_page);
2355 page_cache_release(old_page);
2356 return 0;
2359 /* Return the pagecache page at a given address within a VMA */
2360 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2361 struct vm_area_struct *vma, unsigned long address)
2363 struct address_space *mapping;
2364 pgoff_t idx;
2366 mapping = vma->vm_file->f_mapping;
2367 idx = vma_hugecache_offset(h, vma, address);
2369 return find_lock_page(mapping, idx);
2373 * Return whether there is a pagecache page to back given address within VMA.
2374 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2376 static bool hugetlbfs_pagecache_present(struct hstate *h,
2377 struct vm_area_struct *vma, unsigned long address)
2379 struct address_space *mapping;
2380 pgoff_t idx;
2381 struct page *page;
2383 mapping = vma->vm_file->f_mapping;
2384 idx = vma_hugecache_offset(h, vma, address);
2386 page = find_get_page(mapping, idx);
2387 if (page)
2388 put_page(page);
2389 return page != NULL;
2392 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2393 unsigned long address, pte_t *ptep, unsigned int flags)
2395 struct hstate *h = hstate_vma(vma);
2396 int ret = VM_FAULT_SIGBUS;
2397 pgoff_t idx;
2398 unsigned long size;
2399 struct page *page;
2400 struct address_space *mapping;
2401 pte_t new_pte;
2404 * Currently, we are forced to kill the process in the event the
2405 * original mapper has unmapped pages from the child due to a failed
2406 * COW. Warn that such a situation has occured as it may not be obvious
2408 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2409 printk(KERN_WARNING
2410 "PID %d killed due to inadequate hugepage pool\n",
2411 current->pid);
2412 return ret;
2415 mapping = vma->vm_file->f_mapping;
2416 idx = vma_hugecache_offset(h, vma, address);
2419 * Use page lock to guard against racing truncation
2420 * before we get page_table_lock.
2422 retry:
2423 page = find_lock_page(mapping, idx);
2424 if (!page) {
2425 size = i_size_read(mapping->host) >> huge_page_shift(h);
2426 if (idx >= size)
2427 goto out;
2428 page = alloc_huge_page(vma, address, 0);
2429 if (IS_ERR(page)) {
2430 ret = -PTR_ERR(page);
2431 goto out;
2433 clear_huge_page(page, address, huge_page_size(h));
2434 __SetPageUptodate(page);
2436 if (vma->vm_flags & VM_MAYSHARE) {
2437 int err;
2438 struct inode *inode = mapping->host;
2440 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2441 if (err) {
2442 put_page(page);
2443 if (err == -EEXIST)
2444 goto retry;
2445 goto out;
2448 spin_lock(&inode->i_lock);
2449 inode->i_blocks += blocks_per_huge_page(h);
2450 spin_unlock(&inode->i_lock);
2451 } else
2452 lock_page(page);
2456 * If we are going to COW a private mapping later, we examine the
2457 * pending reservations for this page now. This will ensure that
2458 * any allocations necessary to record that reservation occur outside
2459 * the spinlock.
2461 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2462 if (vma_needs_reservation(h, vma, address) < 0) {
2463 ret = VM_FAULT_OOM;
2464 goto backout_unlocked;
2467 spin_lock(&mm->page_table_lock);
2468 size = i_size_read(mapping->host) >> huge_page_shift(h);
2469 if (idx >= size)
2470 goto backout;
2472 ret = 0;
2473 if (!huge_pte_none(huge_ptep_get(ptep)))
2474 goto backout;
2476 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2477 && (vma->vm_flags & VM_SHARED)));
2478 set_huge_pte_at(mm, address, ptep, new_pte);
2480 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2481 /* Optimization, do the COW without a second fault */
2482 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2485 spin_unlock(&mm->page_table_lock);
2486 unlock_page(page);
2487 out:
2488 return ret;
2490 backout:
2491 spin_unlock(&mm->page_table_lock);
2492 backout_unlocked:
2493 unlock_page(page);
2494 put_page(page);
2495 goto out;
2498 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2499 unsigned long address, unsigned int flags)
2501 pte_t *ptep;
2502 pte_t entry;
2503 int ret;
2504 struct page *pagecache_page = NULL;
2505 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2506 struct hstate *h = hstate_vma(vma);
2508 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2509 if (!ptep)
2510 return VM_FAULT_OOM;
2513 * Serialize hugepage allocation and instantiation, so that we don't
2514 * get spurious allocation failures if two CPUs race to instantiate
2515 * the same page in the page cache.
2517 mutex_lock(&hugetlb_instantiation_mutex);
2518 entry = huge_ptep_get(ptep);
2519 if (huge_pte_none(entry)) {
2520 ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2521 goto out_mutex;
2524 ret = 0;
2527 * If we are going to COW the mapping later, we examine the pending
2528 * reservations for this page now. This will ensure that any
2529 * allocations necessary to record that reservation occur outside the
2530 * spinlock. For private mappings, we also lookup the pagecache
2531 * page now as it is used to determine if a reservation has been
2532 * consumed.
2534 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2535 if (vma_needs_reservation(h, vma, address) < 0) {
2536 ret = VM_FAULT_OOM;
2537 goto out_mutex;
2540 if (!(vma->vm_flags & VM_MAYSHARE))
2541 pagecache_page = hugetlbfs_pagecache_page(h,
2542 vma, address);
2545 spin_lock(&mm->page_table_lock);
2546 /* Check for a racing update before calling hugetlb_cow */
2547 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
2548 goto out_page_table_lock;
2551 if (flags & FAULT_FLAG_WRITE) {
2552 if (!pte_write(entry)) {
2553 ret = hugetlb_cow(mm, vma, address, ptep, entry,
2554 pagecache_page);
2555 goto out_page_table_lock;
2557 entry = pte_mkdirty(entry);
2559 entry = pte_mkyoung(entry);
2560 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
2561 flags & FAULT_FLAG_WRITE))
2562 update_mmu_cache(vma, address, entry);
2564 out_page_table_lock:
2565 spin_unlock(&mm->page_table_lock);
2567 if (pagecache_page) {
2568 unlock_page(pagecache_page);
2569 put_page(pagecache_page);
2572 out_mutex:
2573 mutex_unlock(&hugetlb_instantiation_mutex);
2575 return ret;
2578 /* Can be overriden by architectures */
2579 __attribute__((weak)) struct page *
2580 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2581 pud_t *pud, int write)
2583 BUG();
2584 return NULL;
2587 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2588 struct page **pages, struct vm_area_struct **vmas,
2589 unsigned long *position, int *length, int i,
2590 unsigned int flags)
2592 unsigned long pfn_offset;
2593 unsigned long vaddr = *position;
2594 int remainder = *length;
2595 struct hstate *h = hstate_vma(vma);
2597 spin_lock(&mm->page_table_lock);
2598 while (vaddr < vma->vm_end && remainder) {
2599 pte_t *pte;
2600 int absent;
2601 struct page *page;
2604 * Some archs (sparc64, sh*) have multiple pte_ts to
2605 * each hugepage. We have to make sure we get the
2606 * first, for the page indexing below to work.
2608 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2609 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2612 * When coredumping, it suits get_dump_page if we just return
2613 * an error where there's an empty slot with no huge pagecache
2614 * to back it. This way, we avoid allocating a hugepage, and
2615 * the sparse dumpfile avoids allocating disk blocks, but its
2616 * huge holes still show up with zeroes where they need to be.
2618 if (absent && (flags & FOLL_DUMP) &&
2619 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
2620 remainder = 0;
2621 break;
2624 if (absent ||
2625 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
2626 int ret;
2628 spin_unlock(&mm->page_table_lock);
2629 ret = hugetlb_fault(mm, vma, vaddr,
2630 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
2631 spin_lock(&mm->page_table_lock);
2632 if (!(ret & VM_FAULT_ERROR))
2633 continue;
2635 remainder = 0;
2636 break;
2639 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2640 page = pte_page(huge_ptep_get(pte));
2641 same_page:
2642 if (pages) {
2643 pages[i] = mem_map_offset(page, pfn_offset);
2644 get_page(pages[i]);
2647 if (vmas)
2648 vmas[i] = vma;
2650 vaddr += PAGE_SIZE;
2651 ++pfn_offset;
2652 --remainder;
2653 ++i;
2654 if (vaddr < vma->vm_end && remainder &&
2655 pfn_offset < pages_per_huge_page(h)) {
2657 * We use pfn_offset to avoid touching the pageframes
2658 * of this compound page.
2660 goto same_page;
2663 spin_unlock(&mm->page_table_lock);
2664 *length = remainder;
2665 *position = vaddr;
2667 return i ? i : -EFAULT;
2670 void hugetlb_change_protection(struct vm_area_struct *vma,
2671 unsigned long address, unsigned long end, pgprot_t newprot)
2673 struct mm_struct *mm = vma->vm_mm;
2674 unsigned long start = address;
2675 pte_t *ptep;
2676 pte_t pte;
2677 struct hstate *h = hstate_vma(vma);
2679 BUG_ON(address >= end);
2680 flush_cache_range(vma, address, end);
2682 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2683 spin_lock(&mm->page_table_lock);
2684 for (; address < end; address += huge_page_size(h)) {
2685 ptep = huge_pte_offset(mm, address);
2686 if (!ptep)
2687 continue;
2688 if (huge_pmd_unshare(mm, &address, ptep))
2689 continue;
2690 if (!huge_pte_none(huge_ptep_get(ptep))) {
2691 pte = huge_ptep_get_and_clear(mm, address, ptep);
2692 pte = pte_mkhuge(pte_modify(pte, newprot));
2693 set_huge_pte_at(mm, address, ptep, pte);
2696 spin_unlock(&mm->page_table_lock);
2697 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2699 flush_tlb_range(vma, start, end);
2702 int hugetlb_reserve_pages(struct inode *inode,
2703 long from, long to,
2704 struct vm_area_struct *vma,
2705 int acctflag)
2707 long ret, chg;
2708 struct hstate *h = hstate_inode(inode);
2711 * Only apply hugepage reservation if asked. At fault time, an
2712 * attempt will be made for VM_NORESERVE to allocate a page
2713 * and filesystem quota without using reserves
2715 if (acctflag & VM_NORESERVE)
2716 return 0;
2719 * Shared mappings base their reservation on the number of pages that
2720 * are already allocated on behalf of the file. Private mappings need
2721 * to reserve the full area even if read-only as mprotect() may be
2722 * called to make the mapping read-write. Assume !vma is a shm mapping
2724 if (!vma || vma->vm_flags & VM_MAYSHARE)
2725 chg = region_chg(&inode->i_mapping->private_list, from, to);
2726 else {
2727 struct resv_map *resv_map = resv_map_alloc();
2728 if (!resv_map)
2729 return -ENOMEM;
2731 chg = to - from;
2733 set_vma_resv_map(vma, resv_map);
2734 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2737 if (chg < 0)
2738 return chg;
2740 /* There must be enough filesystem quota for the mapping */
2741 if (hugetlb_get_quota(inode->i_mapping, chg))
2742 return -ENOSPC;
2745 * Check enough hugepages are available for the reservation.
2746 * Hand back the quota if there are not
2748 ret = hugetlb_acct_memory(h, chg);
2749 if (ret < 0) {
2750 hugetlb_put_quota(inode->i_mapping, chg);
2751 return ret;
2755 * Account for the reservations made. Shared mappings record regions
2756 * that have reservations as they are shared by multiple VMAs.
2757 * When the last VMA disappears, the region map says how much
2758 * the reservation was and the page cache tells how much of
2759 * the reservation was consumed. Private mappings are per-VMA and
2760 * only the consumed reservations are tracked. When the VMA
2761 * disappears, the original reservation is the VMA size and the
2762 * consumed reservations are stored in the map. Hence, nothing
2763 * else has to be done for private mappings here
2765 if (!vma || vma->vm_flags & VM_MAYSHARE)
2766 region_add(&inode->i_mapping->private_list, from, to);
2767 return 0;
2770 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2772 struct hstate *h = hstate_inode(inode);
2773 long chg = region_truncate(&inode->i_mapping->private_list, offset);
2775 spin_lock(&inode->i_lock);
2776 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
2777 spin_unlock(&inode->i_lock);
2779 hugetlb_put_quota(inode->i_mapping, (chg - freed));
2780 hugetlb_acct_memory(h, -(chg - freed));