2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.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>
23 #include <asm/pgtable.h>
26 #include <linux/hugetlb.h>
29 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
30 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
31 unsigned long hugepages_treat_as_movable
;
33 static int max_hstate
;
34 unsigned int default_hstate_idx
;
35 struct hstate hstates
[HUGE_MAX_HSTATE
];
37 __initdata
LIST_HEAD(huge_boot_pages
);
39 /* for command line parsing */
40 static struct hstate
* __initdata parsed_hstate
;
41 static unsigned long __initdata default_hstate_max_huge_pages
;
42 static unsigned long __initdata default_hstate_size
;
44 #define for_each_hstate(h) \
45 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
48 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
50 static DEFINE_SPINLOCK(hugetlb_lock
);
53 * Region tracking -- allows tracking of reservations and instantiated pages
54 * across the pages in a mapping.
56 * The region data structures are protected by a combination of the mmap_sem
57 * and the hugetlb_instantion_mutex. To access or modify a region the caller
58 * must either hold the mmap_sem for write, or the mmap_sem for read and
59 * the hugetlb_instantiation mutex:
61 * down_write(&mm->mmap_sem);
63 * down_read(&mm->mmap_sem);
64 * mutex_lock(&hugetlb_instantiation_mutex);
67 struct list_head link
;
72 static long region_add(struct list_head
*head
, long f
, long t
)
74 struct file_region
*rg
, *nrg
, *trg
;
76 /* Locate the region we are either in or before. */
77 list_for_each_entry(rg
, head
, link
)
81 /* Round our left edge to the current segment if it encloses us. */
85 /* Check for and consume any regions we now overlap with. */
87 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
88 if (&rg
->link
== head
)
93 /* If this area reaches higher then extend our area to
94 * include it completely. If this is not the first area
95 * which we intend to reuse, free it. */
108 static long region_chg(struct list_head
*head
, long f
, long t
)
110 struct file_region
*rg
, *nrg
;
113 /* Locate the region we are before or in. */
114 list_for_each_entry(rg
, head
, link
)
118 /* If we are below the current region then a new region is required.
119 * Subtle, allocate a new region at the position but make it zero
120 * size such that we can guarantee to record the reservation. */
121 if (&rg
->link
== head
|| t
< rg
->from
) {
122 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
127 INIT_LIST_HEAD(&nrg
->link
);
128 list_add(&nrg
->link
, rg
->link
.prev
);
133 /* Round our left edge to the current segment if it encloses us. */
138 /* Check for and consume any regions we now overlap with. */
139 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
140 if (&rg
->link
== head
)
145 /* We overlap with this area, if it extends futher than
146 * us then we must extend ourselves. Account for its
147 * existing reservation. */
152 chg
-= rg
->to
- rg
->from
;
157 static long region_truncate(struct list_head
*head
, long end
)
159 struct file_region
*rg
, *trg
;
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg
, head
, link
)
166 if (&rg
->link
== head
)
169 /* If we are in the middle of a region then adjust it. */
170 if (end
> rg
->from
) {
173 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
176 /* Drop any remaining regions. */
177 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
178 if (&rg
->link
== head
)
180 chg
+= rg
->to
- rg
->from
;
187 static long region_count(struct list_head
*head
, long f
, long t
)
189 struct file_region
*rg
;
192 /* Locate each segment we overlap with, and count that overlap. */
193 list_for_each_entry(rg
, head
, link
) {
202 seg_from
= max(rg
->from
, f
);
203 seg_to
= min(rg
->to
, t
);
205 chg
+= seg_to
- seg_from
;
212 * Convert the address within this vma to the page offset within
213 * the mapping, in pagecache page units; huge pages here.
215 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
216 struct vm_area_struct
*vma
, unsigned long address
)
218 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
219 (vma
->vm_pgoff
>> huge_page_order(h
));
223 * Return the size of the pages allocated when backing a VMA. In the majority
224 * cases this will be same size as used by the page table entries.
226 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
228 struct hstate
*hstate
;
230 if (!is_vm_hugetlb_page(vma
))
233 hstate
= hstate_vma(vma
);
235 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
237 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
240 * Return the page size being used by the MMU to back a VMA. In the majority
241 * of cases, the page size used by the kernel matches the MMU size. On
242 * architectures where it differs, an architecture-specific version of this
243 * function is required.
245 #ifndef vma_mmu_pagesize
246 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
248 return vma_kernel_pagesize(vma
);
253 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
254 * bits of the reservation map pointer, which are always clear due to
257 #define HPAGE_RESV_OWNER (1UL << 0)
258 #define HPAGE_RESV_UNMAPPED (1UL << 1)
259 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
262 * These helpers are used to track how many pages are reserved for
263 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
264 * is guaranteed to have their future faults succeed.
266 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
267 * the reserve counters are updated with the hugetlb_lock held. It is safe
268 * to reset the VMA at fork() time as it is not in use yet and there is no
269 * chance of the global counters getting corrupted as a result of the values.
271 * The private mapping reservation is represented in a subtly different
272 * manner to a shared mapping. A shared mapping has a region map associated
273 * with the underlying file, this region map represents the backing file
274 * pages which have ever had a reservation assigned which this persists even
275 * after the page is instantiated. A private mapping has a region map
276 * associated with the original mmap which is attached to all VMAs which
277 * reference it, this region map represents those offsets which have consumed
278 * reservation ie. where pages have been instantiated.
280 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
282 return (unsigned long)vma
->vm_private_data
;
285 static void set_vma_private_data(struct vm_area_struct
*vma
,
288 vma
->vm_private_data
= (void *)value
;
293 struct list_head regions
;
296 static struct resv_map
*resv_map_alloc(void)
298 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
302 kref_init(&resv_map
->refs
);
303 INIT_LIST_HEAD(&resv_map
->regions
);
308 static void resv_map_release(struct kref
*ref
)
310 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
312 /* Clear out any active regions before we release the map. */
313 region_truncate(&resv_map
->regions
, 0);
317 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
319 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
320 if (!(vma
->vm_flags
& VM_MAYSHARE
))
321 return (struct resv_map
*)(get_vma_private_data(vma
) &
326 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
328 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
329 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
331 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
332 HPAGE_RESV_MASK
) | (unsigned long)map
);
335 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
337 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
338 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
340 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
343 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
345 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
347 return (get_vma_private_data(vma
) & flag
) != 0;
350 /* Decrement the reserved pages in the hugepage pool by one */
351 static void decrement_hugepage_resv_vma(struct hstate
*h
,
352 struct vm_area_struct
*vma
)
354 if (vma
->vm_flags
& VM_NORESERVE
)
357 if (vma
->vm_flags
& VM_MAYSHARE
) {
358 /* Shared mappings always use reserves */
359 h
->resv_huge_pages
--;
360 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
362 * Only the process that called mmap() has reserves for
365 h
->resv_huge_pages
--;
369 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
370 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
372 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
373 if (!(vma
->vm_flags
& VM_MAYSHARE
))
374 vma
->vm_private_data
= (void *)0;
377 /* Returns true if the VMA has associated reserve pages */
378 static int vma_has_reserves(struct vm_area_struct
*vma
)
380 if (vma
->vm_flags
& VM_MAYSHARE
)
382 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
387 static void clear_gigantic_page(struct page
*page
,
388 unsigned long addr
, unsigned long sz
)
391 struct page
*p
= page
;
394 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++, p
= mem_map_next(p
, page
, i
)) {
396 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
399 static void clear_huge_page(struct page
*page
,
400 unsigned long addr
, unsigned long sz
)
404 if (unlikely(sz
> MAX_ORDER_NR_PAGES
)) {
405 clear_gigantic_page(page
, addr
, sz
);
410 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
412 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
416 static void copy_gigantic_page(struct page
*dst
, struct page
*src
,
417 unsigned long addr
, struct vm_area_struct
*vma
)
420 struct hstate
*h
= hstate_vma(vma
);
421 struct page
*dst_base
= dst
;
422 struct page
*src_base
= src
;
424 for (i
= 0; i
< pages_per_huge_page(h
); ) {
426 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
429 dst
= mem_map_next(dst
, dst_base
, i
);
430 src
= mem_map_next(src
, src_base
, i
);
433 static void copy_huge_page(struct page
*dst
, struct page
*src
,
434 unsigned long addr
, struct vm_area_struct
*vma
)
437 struct hstate
*h
= hstate_vma(vma
);
439 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
440 copy_gigantic_page(dst
, src
, addr
, vma
);
445 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
447 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
451 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
453 int nid
= page_to_nid(page
);
454 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
455 h
->free_huge_pages
++;
456 h
->free_huge_pages_node
[nid
]++;
459 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
460 struct vm_area_struct
*vma
,
461 unsigned long address
, int avoid_reserve
)
464 struct page
*page
= NULL
;
465 struct mempolicy
*mpol
;
466 nodemask_t
*nodemask
;
467 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
468 htlb_alloc_mask
, &mpol
, &nodemask
);
473 * A child process with MAP_PRIVATE mappings created by their parent
474 * have no page reserves. This check ensures that reservations are
475 * not "stolen". The child may still get SIGKILLed
477 if (!vma_has_reserves(vma
) &&
478 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
481 /* If reserves cannot be used, ensure enough pages are in the pool */
482 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
485 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
486 MAX_NR_ZONES
- 1, nodemask
) {
487 nid
= zone_to_nid(zone
);
488 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
489 !list_empty(&h
->hugepage_freelists
[nid
])) {
490 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
492 list_del(&page
->lru
);
493 h
->free_huge_pages
--;
494 h
->free_huge_pages_node
[nid
]--;
497 decrement_hugepage_resv_vma(h
, vma
);
506 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
510 VM_BUG_ON(h
->order
>= MAX_ORDER
);
513 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
514 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
515 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
516 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
517 1 << PG_private
| 1<< PG_writeback
);
519 set_compound_page_dtor(page
, NULL
);
520 set_page_refcounted(page
);
521 arch_release_hugepage(page
);
522 __free_pages(page
, huge_page_order(h
));
525 struct hstate
*size_to_hstate(unsigned long size
)
530 if (huge_page_size(h
) == size
)
536 static void free_huge_page(struct page
*page
)
539 * Can't pass hstate in here because it is called from the
540 * compound page destructor.
542 struct hstate
*h
= page_hstate(page
);
543 int nid
= page_to_nid(page
);
544 struct address_space
*mapping
;
546 mapping
= (struct address_space
*) page_private(page
);
547 set_page_private(page
, 0);
548 BUG_ON(page_count(page
));
549 INIT_LIST_HEAD(&page
->lru
);
551 spin_lock(&hugetlb_lock
);
552 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
553 update_and_free_page(h
, page
);
554 h
->surplus_huge_pages
--;
555 h
->surplus_huge_pages_node
[nid
]--;
557 enqueue_huge_page(h
, page
);
559 spin_unlock(&hugetlb_lock
);
561 hugetlb_put_quota(mapping
, 1);
564 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
566 set_compound_page_dtor(page
, free_huge_page
);
567 spin_lock(&hugetlb_lock
);
569 h
->nr_huge_pages_node
[nid
]++;
570 spin_unlock(&hugetlb_lock
);
571 put_page(page
); /* free it into the hugepage allocator */
574 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
577 int nr_pages
= 1 << order
;
578 struct page
*p
= page
+ 1;
580 /* we rely on prep_new_huge_page to set the destructor */
581 set_compound_order(page
, order
);
583 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
585 p
->first_page
= page
;
589 int PageHuge(struct page
*page
)
591 compound_page_dtor
*dtor
;
593 if (!PageCompound(page
))
596 page
= compound_head(page
);
597 dtor
= get_compound_page_dtor(page
);
599 return dtor
== free_huge_page
;
602 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
606 if (h
->order
>= MAX_ORDER
)
609 page
= alloc_pages_exact_node(nid
,
610 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
611 __GFP_REPEAT
|__GFP_NOWARN
,
614 if (arch_prepare_hugepage(page
)) {
615 __free_pages(page
, huge_page_order(h
));
618 prep_new_huge_page(h
, page
, nid
);
625 * common helper function for hstate_next_node_to_{alloc|free}.
626 * return next node in node_online_map, wrapping at end.
628 static int next_node_allowed(int nid
)
630 nid
= next_node(nid
, node_online_map
);
631 if (nid
== MAX_NUMNODES
)
632 nid
= first_node(node_online_map
);
633 VM_BUG_ON(nid
>= MAX_NUMNODES
);
639 * Use a helper variable to find the next node and then
640 * copy it back to next_nid_to_alloc afterwards:
641 * otherwise there's a window in which a racer might
642 * pass invalid nid MAX_NUMNODES to alloc_pages_exact_node.
643 * But we don't need to use a spin_lock here: it really
644 * doesn't matter if occasionally a racer chooses the
645 * same nid as we do. Move nid forward in the mask even
646 * if we just successfully allocated a hugepage so that
647 * the next caller gets hugepages on the next node.
649 static int hstate_next_node_to_alloc(struct hstate
*h
)
653 nid
= h
->next_nid_to_alloc
;
654 next_nid
= next_node_allowed(nid
);
655 h
->next_nid_to_alloc
= next_nid
;
659 static int alloc_fresh_huge_page(struct hstate
*h
)
666 start_nid
= hstate_next_node_to_alloc(h
);
667 next_nid
= start_nid
;
670 page
= alloc_fresh_huge_page_node(h
, next_nid
);
675 next_nid
= hstate_next_node_to_alloc(h
);
676 } while (next_nid
!= start_nid
);
679 count_vm_event(HTLB_BUDDY_PGALLOC
);
681 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
687 * helper for free_pool_huge_page() - return the next node
688 * from which to free a huge page. Advance the next node id
689 * whether or not we find a free huge page to free so that the
690 * next attempt to free addresses the next node.
692 static int hstate_next_node_to_free(struct hstate
*h
)
696 nid
= h
->next_nid_to_free
;
697 next_nid
= next_node_allowed(nid
);
698 h
->next_nid_to_free
= next_nid
;
703 * Free huge page from pool from next node to free.
704 * Attempt to keep persistent huge pages more or less
705 * balanced over allowed nodes.
706 * Called with hugetlb_lock locked.
708 static int free_pool_huge_page(struct hstate
*h
, bool acct_surplus
)
714 start_nid
= hstate_next_node_to_free(h
);
715 next_nid
= start_nid
;
719 * If we're returning unused surplus pages, only examine
720 * nodes with surplus pages.
722 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
723 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
725 list_entry(h
->hugepage_freelists
[next_nid
].next
,
727 list_del(&page
->lru
);
728 h
->free_huge_pages
--;
729 h
->free_huge_pages_node
[next_nid
]--;
731 h
->surplus_huge_pages
--;
732 h
->surplus_huge_pages_node
[next_nid
]--;
734 update_and_free_page(h
, page
);
738 next_nid
= hstate_next_node_to_free(h
);
739 } while (next_nid
!= start_nid
);
744 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
745 struct vm_area_struct
*vma
, unsigned long address
)
750 if (h
->order
>= MAX_ORDER
)
754 * Assume we will successfully allocate the surplus page to
755 * prevent racing processes from causing the surplus to exceed
758 * This however introduces a different race, where a process B
759 * tries to grow the static hugepage pool while alloc_pages() is
760 * called by process A. B will only examine the per-node
761 * counters in determining if surplus huge pages can be
762 * converted to normal huge pages in adjust_pool_surplus(). A
763 * won't be able to increment the per-node counter, until the
764 * lock is dropped by B, but B doesn't drop hugetlb_lock until
765 * no more huge pages can be converted from surplus to normal
766 * state (and doesn't try to convert again). Thus, we have a
767 * case where a surplus huge page exists, the pool is grown, and
768 * the surplus huge page still exists after, even though it
769 * should just have been converted to a normal huge page. This
770 * does not leak memory, though, as the hugepage will be freed
771 * once it is out of use. It also does not allow the counters to
772 * go out of whack in adjust_pool_surplus() as we don't modify
773 * the node values until we've gotten the hugepage and only the
774 * per-node value is checked there.
776 spin_lock(&hugetlb_lock
);
777 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
778 spin_unlock(&hugetlb_lock
);
782 h
->surplus_huge_pages
++;
784 spin_unlock(&hugetlb_lock
);
786 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
787 __GFP_REPEAT
|__GFP_NOWARN
,
790 if (page
&& arch_prepare_hugepage(page
)) {
791 __free_pages(page
, huge_page_order(h
));
795 spin_lock(&hugetlb_lock
);
798 * This page is now managed by the hugetlb allocator and has
799 * no users -- drop the buddy allocator's reference.
801 put_page_testzero(page
);
802 VM_BUG_ON(page_count(page
));
803 nid
= page_to_nid(page
);
804 set_compound_page_dtor(page
, free_huge_page
);
806 * We incremented the global counters already
808 h
->nr_huge_pages_node
[nid
]++;
809 h
->surplus_huge_pages_node
[nid
]++;
810 __count_vm_event(HTLB_BUDDY_PGALLOC
);
813 h
->surplus_huge_pages
--;
814 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
816 spin_unlock(&hugetlb_lock
);
822 * Increase the hugetlb pool such that it can accomodate a reservation
825 static int gather_surplus_pages(struct hstate
*h
, int delta
)
827 struct list_head surplus_list
;
828 struct page
*page
, *tmp
;
830 int needed
, allocated
;
832 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
834 h
->resv_huge_pages
+= delta
;
839 INIT_LIST_HEAD(&surplus_list
);
843 spin_unlock(&hugetlb_lock
);
844 for (i
= 0; i
< needed
; i
++) {
845 page
= alloc_buddy_huge_page(h
, NULL
, 0);
848 * We were not able to allocate enough pages to
849 * satisfy the entire reservation so we free what
850 * we've allocated so far.
852 spin_lock(&hugetlb_lock
);
857 list_add(&page
->lru
, &surplus_list
);
862 * After retaking hugetlb_lock, we need to recalculate 'needed'
863 * because either resv_huge_pages or free_huge_pages may have changed.
865 spin_lock(&hugetlb_lock
);
866 needed
= (h
->resv_huge_pages
+ delta
) -
867 (h
->free_huge_pages
+ allocated
);
872 * The surplus_list now contains _at_least_ the number of extra pages
873 * needed to accomodate the reservation. Add the appropriate number
874 * of pages to the hugetlb pool and free the extras back to the buddy
875 * allocator. Commit the entire reservation here to prevent another
876 * process from stealing the pages as they are added to the pool but
877 * before they are reserved.
880 h
->resv_huge_pages
+= delta
;
883 /* Free the needed pages to the hugetlb pool */
884 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
887 list_del(&page
->lru
);
888 enqueue_huge_page(h
, page
);
891 /* Free unnecessary surplus pages to the buddy allocator */
892 if (!list_empty(&surplus_list
)) {
893 spin_unlock(&hugetlb_lock
);
894 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
895 list_del(&page
->lru
);
897 * The page has a reference count of zero already, so
898 * call free_huge_page directly instead of using
899 * put_page. This must be done with hugetlb_lock
900 * unlocked which is safe because free_huge_page takes
901 * hugetlb_lock before deciding how to free the page.
903 free_huge_page(page
);
905 spin_lock(&hugetlb_lock
);
912 * When releasing a hugetlb pool reservation, any surplus pages that were
913 * allocated to satisfy the reservation must be explicitly freed if they were
915 * Called with hugetlb_lock held.
917 static void return_unused_surplus_pages(struct hstate
*h
,
918 unsigned long unused_resv_pages
)
920 unsigned long nr_pages
;
922 /* Uncommit the reservation */
923 h
->resv_huge_pages
-= unused_resv_pages
;
925 /* Cannot return gigantic pages currently */
926 if (h
->order
>= MAX_ORDER
)
929 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
932 * We want to release as many surplus pages as possible, spread
933 * evenly across all nodes. Iterate across all nodes until we
934 * can no longer free unreserved surplus pages. This occurs when
935 * the nodes with surplus pages have no free pages.
936 * free_pool_huge_page() will balance the the frees across the
937 * on-line nodes for us and will handle the hstate accounting.
940 if (!free_pool_huge_page(h
, 1))
946 * Determine if the huge page at addr within the vma has an associated
947 * reservation. Where it does not we will need to logically increase
948 * reservation and actually increase quota before an allocation can occur.
949 * Where any new reservation would be required the reservation change is
950 * prepared, but not committed. Once the page has been quota'd allocated
951 * an instantiated the change should be committed via vma_commit_reservation.
952 * No action is required on failure.
954 static long vma_needs_reservation(struct hstate
*h
,
955 struct vm_area_struct
*vma
, unsigned long addr
)
957 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
958 struct inode
*inode
= mapping
->host
;
960 if (vma
->vm_flags
& VM_MAYSHARE
) {
961 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
962 return region_chg(&inode
->i_mapping
->private_list
,
965 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
970 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
971 struct resv_map
*reservations
= vma_resv_map(vma
);
973 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
979 static void vma_commit_reservation(struct hstate
*h
,
980 struct vm_area_struct
*vma
, unsigned long addr
)
982 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
983 struct inode
*inode
= mapping
->host
;
985 if (vma
->vm_flags
& VM_MAYSHARE
) {
986 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
987 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
989 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
990 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
991 struct resv_map
*reservations
= vma_resv_map(vma
);
993 /* Mark this page used in the map. */
994 region_add(&reservations
->regions
, idx
, idx
+ 1);
998 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
999 unsigned long addr
, int avoid_reserve
)
1001 struct hstate
*h
= hstate_vma(vma
);
1003 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1004 struct inode
*inode
= mapping
->host
;
1008 * Processes that did not create the mapping will have no reserves and
1009 * will not have accounted against quota. Check that the quota can be
1010 * made before satisfying the allocation
1011 * MAP_NORESERVE mappings may also need pages and quota allocated
1012 * if no reserve mapping overlaps.
1014 chg
= vma_needs_reservation(h
, vma
, addr
);
1016 return ERR_PTR(chg
);
1018 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1019 return ERR_PTR(-ENOSPC
);
1021 spin_lock(&hugetlb_lock
);
1022 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1023 spin_unlock(&hugetlb_lock
);
1026 page
= alloc_buddy_huge_page(h
, vma
, addr
);
1028 hugetlb_put_quota(inode
->i_mapping
, chg
);
1029 return ERR_PTR(-VM_FAULT_OOM
);
1033 set_page_refcounted(page
);
1034 set_page_private(page
, (unsigned long) mapping
);
1036 vma_commit_reservation(h
, vma
, addr
);
1041 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1043 struct huge_bootmem_page
*m
;
1044 int nr_nodes
= nodes_weight(node_online_map
);
1049 addr
= __alloc_bootmem_node_nopanic(
1050 NODE_DATA(hstate_next_node_to_alloc(h
)),
1051 huge_page_size(h
), huge_page_size(h
), 0);
1055 * Use the beginning of the huge page to store the
1056 * huge_bootmem_page struct (until gather_bootmem
1057 * puts them into the mem_map).
1067 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1068 /* Put them into a private list first because mem_map is not up yet */
1069 list_add(&m
->list
, &huge_boot_pages
);
1074 static void prep_compound_huge_page(struct page
*page
, int order
)
1076 if (unlikely(order
> (MAX_ORDER
- 1)))
1077 prep_compound_gigantic_page(page
, order
);
1079 prep_compound_page(page
, order
);
1082 /* Put bootmem huge pages into the standard lists after mem_map is up */
1083 static void __init
gather_bootmem_prealloc(void)
1085 struct huge_bootmem_page
*m
;
1087 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1088 struct page
*page
= virt_to_page(m
);
1089 struct hstate
*h
= m
->hstate
;
1090 __ClearPageReserved(page
);
1091 WARN_ON(page_count(page
) != 1);
1092 prep_compound_huge_page(page
, h
->order
);
1093 prep_new_huge_page(h
, page
, page_to_nid(page
));
1097 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1101 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1102 if (h
->order
>= MAX_ORDER
) {
1103 if (!alloc_bootmem_huge_page(h
))
1105 } else if (!alloc_fresh_huge_page(h
))
1108 h
->max_huge_pages
= i
;
1111 static void __init
hugetlb_init_hstates(void)
1115 for_each_hstate(h
) {
1116 /* oversize hugepages were init'ed in early boot */
1117 if (h
->order
< MAX_ORDER
)
1118 hugetlb_hstate_alloc_pages(h
);
1122 static char * __init
memfmt(char *buf
, unsigned long n
)
1124 if (n
>= (1UL << 30))
1125 sprintf(buf
, "%lu GB", n
>> 30);
1126 else if (n
>= (1UL << 20))
1127 sprintf(buf
, "%lu MB", n
>> 20);
1129 sprintf(buf
, "%lu KB", n
>> 10);
1133 static void __init
report_hugepages(void)
1137 for_each_hstate(h
) {
1139 printk(KERN_INFO
"HugeTLB registered %s page size, "
1140 "pre-allocated %ld pages\n",
1141 memfmt(buf
, huge_page_size(h
)),
1142 h
->free_huge_pages
);
1146 #ifdef CONFIG_HIGHMEM
1147 static void try_to_free_low(struct hstate
*h
, unsigned long count
)
1151 if (h
->order
>= MAX_ORDER
)
1154 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
1155 struct page
*page
, *next
;
1156 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1157 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1158 if (count
>= h
->nr_huge_pages
)
1160 if (PageHighMem(page
))
1162 list_del(&page
->lru
);
1163 update_and_free_page(h
, page
);
1164 h
->free_huge_pages
--;
1165 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1170 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
)
1176 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1177 * balanced by operating on them in a round-robin fashion.
1178 * Returns 1 if an adjustment was made.
1180 static int adjust_pool_surplus(struct hstate
*h
, int delta
)
1182 int start_nid
, next_nid
;
1185 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1188 start_nid
= hstate_next_node_to_alloc(h
);
1190 start_nid
= hstate_next_node_to_free(h
);
1191 next_nid
= start_nid
;
1197 * To shrink on this node, there must be a surplus page
1199 if (!h
->surplus_huge_pages_node
[nid
]) {
1200 next_nid
= hstate_next_node_to_alloc(h
);
1206 * Surplus cannot exceed the total number of pages
1208 if (h
->surplus_huge_pages_node
[nid
] >=
1209 h
->nr_huge_pages_node
[nid
]) {
1210 next_nid
= hstate_next_node_to_free(h
);
1215 h
->surplus_huge_pages
+= delta
;
1216 h
->surplus_huge_pages_node
[nid
] += delta
;
1219 } while (next_nid
!= start_nid
);
1224 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1225 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
)
1227 unsigned long min_count
, ret
;
1229 if (h
->order
>= MAX_ORDER
)
1230 return h
->max_huge_pages
;
1233 * Increase the pool size
1234 * First take pages out of surplus state. Then make up the
1235 * remaining difference by allocating fresh huge pages.
1237 * We might race with alloc_buddy_huge_page() here and be unable
1238 * to convert a surplus huge page to a normal huge page. That is
1239 * not critical, though, it just means the overall size of the
1240 * pool might be one hugepage larger than it needs to be, but
1241 * within all the constraints specified by the sysctls.
1243 spin_lock(&hugetlb_lock
);
1244 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1245 if (!adjust_pool_surplus(h
, -1))
1249 while (count
> persistent_huge_pages(h
)) {
1251 * If this allocation races such that we no longer need the
1252 * page, free_huge_page will handle it by freeing the page
1253 * and reducing the surplus.
1255 spin_unlock(&hugetlb_lock
);
1256 ret
= alloc_fresh_huge_page(h
);
1257 spin_lock(&hugetlb_lock
);
1264 * Decrease the pool size
1265 * First return free pages to the buddy allocator (being careful
1266 * to keep enough around to satisfy reservations). Then place
1267 * pages into surplus state as needed so the pool will shrink
1268 * to the desired size as pages become free.
1270 * By placing pages into the surplus state independent of the
1271 * overcommit value, we are allowing the surplus pool size to
1272 * exceed overcommit. There are few sane options here. Since
1273 * alloc_buddy_huge_page() is checking the global counter,
1274 * though, we'll note that we're not allowed to exceed surplus
1275 * and won't grow the pool anywhere else. Not until one of the
1276 * sysctls are changed, or the surplus pages go out of use.
1278 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1279 min_count
= max(count
, min_count
);
1280 try_to_free_low(h
, min_count
);
1281 while (min_count
< persistent_huge_pages(h
)) {
1282 if (!free_pool_huge_page(h
, 0))
1285 while (count
< persistent_huge_pages(h
)) {
1286 if (!adjust_pool_surplus(h
, 1))
1290 ret
= persistent_huge_pages(h
);
1291 spin_unlock(&hugetlb_lock
);
1295 #define HSTATE_ATTR_RO(_name) \
1296 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1298 #define HSTATE_ATTR(_name) \
1299 static struct kobj_attribute _name##_attr = \
1300 __ATTR(_name, 0644, _name##_show, _name##_store)
1302 static struct kobject
*hugepages_kobj
;
1303 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1305 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
)
1308 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1309 if (hstate_kobjs
[i
] == kobj
)
1315 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1316 struct kobj_attribute
*attr
, char *buf
)
1318 struct hstate
*h
= kobj_to_hstate(kobj
);
1319 return sprintf(buf
, "%lu\n", h
->nr_huge_pages
);
1321 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1322 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1325 unsigned long input
;
1326 struct hstate
*h
= kobj_to_hstate(kobj
);
1328 err
= strict_strtoul(buf
, 10, &input
);
1332 h
->max_huge_pages
= set_max_huge_pages(h
, input
);
1336 HSTATE_ATTR(nr_hugepages
);
1338 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1339 struct kobj_attribute
*attr
, char *buf
)
1341 struct hstate
*h
= kobj_to_hstate(kobj
);
1342 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1344 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1345 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1348 unsigned long input
;
1349 struct hstate
*h
= kobj_to_hstate(kobj
);
1351 err
= strict_strtoul(buf
, 10, &input
);
1355 spin_lock(&hugetlb_lock
);
1356 h
->nr_overcommit_huge_pages
= input
;
1357 spin_unlock(&hugetlb_lock
);
1361 HSTATE_ATTR(nr_overcommit_hugepages
);
1363 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1364 struct kobj_attribute
*attr
, char *buf
)
1366 struct hstate
*h
= kobj_to_hstate(kobj
);
1367 return sprintf(buf
, "%lu\n", h
->free_huge_pages
);
1369 HSTATE_ATTR_RO(free_hugepages
);
1371 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1372 struct kobj_attribute
*attr
, char *buf
)
1374 struct hstate
*h
= kobj_to_hstate(kobj
);
1375 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1377 HSTATE_ATTR_RO(resv_hugepages
);
1379 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1380 struct kobj_attribute
*attr
, char *buf
)
1382 struct hstate
*h
= kobj_to_hstate(kobj
);
1383 return sprintf(buf
, "%lu\n", h
->surplus_huge_pages
);
1385 HSTATE_ATTR_RO(surplus_hugepages
);
1387 static struct attribute
*hstate_attrs
[] = {
1388 &nr_hugepages_attr
.attr
,
1389 &nr_overcommit_hugepages_attr
.attr
,
1390 &free_hugepages_attr
.attr
,
1391 &resv_hugepages_attr
.attr
,
1392 &surplus_hugepages_attr
.attr
,
1396 static struct attribute_group hstate_attr_group
= {
1397 .attrs
= hstate_attrs
,
1400 static int __init
hugetlb_sysfs_add_hstate(struct hstate
*h
)
1404 hstate_kobjs
[h
- hstates
] = kobject_create_and_add(h
->name
,
1406 if (!hstate_kobjs
[h
- hstates
])
1409 retval
= sysfs_create_group(hstate_kobjs
[h
- hstates
],
1410 &hstate_attr_group
);
1412 kobject_put(hstate_kobjs
[h
- hstates
]);
1417 static void __init
hugetlb_sysfs_init(void)
1422 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1423 if (!hugepages_kobj
)
1426 for_each_hstate(h
) {
1427 err
= hugetlb_sysfs_add_hstate(h
);
1429 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1434 static void __exit
hugetlb_exit(void)
1438 for_each_hstate(h
) {
1439 kobject_put(hstate_kobjs
[h
- hstates
]);
1442 kobject_put(hugepages_kobj
);
1444 module_exit(hugetlb_exit
);
1446 static int __init
hugetlb_init(void)
1448 /* Some platform decide whether they support huge pages at boot
1449 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1450 * there is no such support
1452 if (HPAGE_SHIFT
== 0)
1455 if (!size_to_hstate(default_hstate_size
)) {
1456 default_hstate_size
= HPAGE_SIZE
;
1457 if (!size_to_hstate(default_hstate_size
))
1458 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1460 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1461 if (default_hstate_max_huge_pages
)
1462 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1464 hugetlb_init_hstates();
1466 gather_bootmem_prealloc();
1470 hugetlb_sysfs_init();
1474 module_init(hugetlb_init
);
1476 /* Should be called on processing a hugepagesz=... option */
1477 void __init
hugetlb_add_hstate(unsigned order
)
1482 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1483 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1486 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1488 h
= &hstates
[max_hstate
++];
1490 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1491 h
->nr_huge_pages
= 0;
1492 h
->free_huge_pages
= 0;
1493 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1494 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1495 h
->next_nid_to_alloc
= first_node(node_online_map
);
1496 h
->next_nid_to_free
= first_node(node_online_map
);
1497 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1498 huge_page_size(h
)/1024);
1503 static int __init
hugetlb_nrpages_setup(char *s
)
1506 static unsigned long *last_mhp
;
1509 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1510 * so this hugepages= parameter goes to the "default hstate".
1513 mhp
= &default_hstate_max_huge_pages
;
1515 mhp
= &parsed_hstate
->max_huge_pages
;
1517 if (mhp
== last_mhp
) {
1518 printk(KERN_WARNING
"hugepages= specified twice without "
1519 "interleaving hugepagesz=, ignoring\n");
1523 if (sscanf(s
, "%lu", mhp
) <= 0)
1527 * Global state is always initialized later in hugetlb_init.
1528 * But we need to allocate >= MAX_ORDER hstates here early to still
1529 * use the bootmem allocator.
1531 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1532 hugetlb_hstate_alloc_pages(parsed_hstate
);
1538 __setup("hugepages=", hugetlb_nrpages_setup
);
1540 static int __init
hugetlb_default_setup(char *s
)
1542 default_hstate_size
= memparse(s
, &s
);
1545 __setup("default_hugepagesz=", hugetlb_default_setup
);
1547 static unsigned int cpuset_mems_nr(unsigned int *array
)
1550 unsigned int nr
= 0;
1552 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1558 #ifdef CONFIG_SYSCTL
1559 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1560 void __user
*buffer
,
1561 size_t *length
, loff_t
*ppos
)
1563 struct hstate
*h
= &default_hstate
;
1567 tmp
= h
->max_huge_pages
;
1570 table
->maxlen
= sizeof(unsigned long);
1571 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1574 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
);
1579 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1580 void __user
*buffer
,
1581 size_t *length
, loff_t
*ppos
)
1583 proc_dointvec(table
, write
, buffer
, length
, ppos
);
1584 if (hugepages_treat_as_movable
)
1585 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1587 htlb_alloc_mask
= GFP_HIGHUSER
;
1591 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1592 void __user
*buffer
,
1593 size_t *length
, loff_t
*ppos
)
1595 struct hstate
*h
= &default_hstate
;
1599 tmp
= h
->nr_overcommit_huge_pages
;
1602 table
->maxlen
= sizeof(unsigned long);
1603 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1606 spin_lock(&hugetlb_lock
);
1607 h
->nr_overcommit_huge_pages
= tmp
;
1608 spin_unlock(&hugetlb_lock
);
1614 #endif /* CONFIG_SYSCTL */
1616 void hugetlb_report_meminfo(struct seq_file
*m
)
1618 struct hstate
*h
= &default_hstate
;
1620 "HugePages_Total: %5lu\n"
1621 "HugePages_Free: %5lu\n"
1622 "HugePages_Rsvd: %5lu\n"
1623 "HugePages_Surp: %5lu\n"
1624 "Hugepagesize: %8lu kB\n",
1628 h
->surplus_huge_pages
,
1629 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1632 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1634 struct hstate
*h
= &default_hstate
;
1636 "Node %d HugePages_Total: %5u\n"
1637 "Node %d HugePages_Free: %5u\n"
1638 "Node %d HugePages_Surp: %5u\n",
1639 nid
, h
->nr_huge_pages_node
[nid
],
1640 nid
, h
->free_huge_pages_node
[nid
],
1641 nid
, h
->surplus_huge_pages_node
[nid
]);
1644 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1645 unsigned long hugetlb_total_pages(void)
1647 struct hstate
*h
= &default_hstate
;
1648 return h
->nr_huge_pages
* pages_per_huge_page(h
);
1651 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
1655 spin_lock(&hugetlb_lock
);
1657 * When cpuset is configured, it breaks the strict hugetlb page
1658 * reservation as the accounting is done on a global variable. Such
1659 * reservation is completely rubbish in the presence of cpuset because
1660 * the reservation is not checked against page availability for the
1661 * current cpuset. Application can still potentially OOM'ed by kernel
1662 * with lack of free htlb page in cpuset that the task is in.
1663 * Attempt to enforce strict accounting with cpuset is almost
1664 * impossible (or too ugly) because cpuset is too fluid that
1665 * task or memory node can be dynamically moved between cpusets.
1667 * The change of semantics for shared hugetlb mapping with cpuset is
1668 * undesirable. However, in order to preserve some of the semantics,
1669 * we fall back to check against current free page availability as
1670 * a best attempt and hopefully to minimize the impact of changing
1671 * semantics that cpuset has.
1674 if (gather_surplus_pages(h
, delta
) < 0)
1677 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
1678 return_unused_surplus_pages(h
, delta
);
1685 return_unused_surplus_pages(h
, (unsigned long) -delta
);
1688 spin_unlock(&hugetlb_lock
);
1692 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
1694 struct resv_map
*reservations
= vma_resv_map(vma
);
1697 * This new VMA should share its siblings reservation map if present.
1698 * The VMA will only ever have a valid reservation map pointer where
1699 * it is being copied for another still existing VMA. As that VMA
1700 * has a reference to the reservation map it cannot dissappear until
1701 * after this open call completes. It is therefore safe to take a
1702 * new reference here without additional locking.
1705 kref_get(&reservations
->refs
);
1708 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
1710 struct hstate
*h
= hstate_vma(vma
);
1711 struct resv_map
*reservations
= vma_resv_map(vma
);
1712 unsigned long reserve
;
1713 unsigned long start
;
1717 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
1718 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
1720 reserve
= (end
- start
) -
1721 region_count(&reservations
->regions
, start
, end
);
1723 kref_put(&reservations
->refs
, resv_map_release
);
1726 hugetlb_acct_memory(h
, -reserve
);
1727 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
1733 * We cannot handle pagefaults against hugetlb pages at all. They cause
1734 * handle_mm_fault() to try to instantiate regular-sized pages in the
1735 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1738 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1744 const struct vm_operations_struct hugetlb_vm_ops
= {
1745 .fault
= hugetlb_vm_op_fault
,
1746 .open
= hugetlb_vm_op_open
,
1747 .close
= hugetlb_vm_op_close
,
1750 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
1757 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
1759 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
1761 entry
= pte_mkyoung(entry
);
1762 entry
= pte_mkhuge(entry
);
1767 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
1768 unsigned long address
, pte_t
*ptep
)
1772 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
1773 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
1774 update_mmu_cache(vma
, address
, entry
);
1779 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
1780 struct vm_area_struct
*vma
)
1782 pte_t
*src_pte
, *dst_pte
, entry
;
1783 struct page
*ptepage
;
1786 struct hstate
*h
= hstate_vma(vma
);
1787 unsigned long sz
= huge_page_size(h
);
1789 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
1791 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
1792 src_pte
= huge_pte_offset(src
, addr
);
1795 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
1799 /* If the pagetables are shared don't copy or take references */
1800 if (dst_pte
== src_pte
)
1803 spin_lock(&dst
->page_table_lock
);
1804 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
1805 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
1807 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
1808 entry
= huge_ptep_get(src_pte
);
1809 ptepage
= pte_page(entry
);
1811 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
1813 spin_unlock(&src
->page_table_lock
);
1814 spin_unlock(&dst
->page_table_lock
);
1822 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1823 unsigned long end
, struct page
*ref_page
)
1825 struct mm_struct
*mm
= vma
->vm_mm
;
1826 unsigned long address
;
1831 struct hstate
*h
= hstate_vma(vma
);
1832 unsigned long sz
= huge_page_size(h
);
1835 * A page gathering list, protected by per file i_mmap_lock. The
1836 * lock is used to avoid list corruption from multiple unmapping
1837 * of the same page since we are using page->lru.
1839 LIST_HEAD(page_list
);
1841 WARN_ON(!is_vm_hugetlb_page(vma
));
1842 BUG_ON(start
& ~huge_page_mask(h
));
1843 BUG_ON(end
& ~huge_page_mask(h
));
1845 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1846 spin_lock(&mm
->page_table_lock
);
1847 for (address
= start
; address
< end
; address
+= sz
) {
1848 ptep
= huge_pte_offset(mm
, address
);
1852 if (huge_pmd_unshare(mm
, &address
, ptep
))
1856 * If a reference page is supplied, it is because a specific
1857 * page is being unmapped, not a range. Ensure the page we
1858 * are about to unmap is the actual page of interest.
1861 pte
= huge_ptep_get(ptep
);
1862 if (huge_pte_none(pte
))
1864 page
= pte_page(pte
);
1865 if (page
!= ref_page
)
1869 * Mark the VMA as having unmapped its page so that
1870 * future faults in this VMA will fail rather than
1871 * looking like data was lost
1873 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
1876 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1877 if (huge_pte_none(pte
))
1880 page
= pte_page(pte
);
1882 set_page_dirty(page
);
1883 list_add(&page
->lru
, &page_list
);
1885 spin_unlock(&mm
->page_table_lock
);
1886 flush_tlb_range(vma
, start
, end
);
1887 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1888 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
1889 list_del(&page
->lru
);
1894 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1895 unsigned long end
, struct page
*ref_page
)
1897 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1898 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
1899 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1903 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1904 * mappping it owns the reserve page for. The intention is to unmap the page
1905 * from other VMAs and let the children be SIGKILLed if they are faulting the
1908 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1909 struct page
*page
, unsigned long address
)
1911 struct hstate
*h
= hstate_vma(vma
);
1912 struct vm_area_struct
*iter_vma
;
1913 struct address_space
*mapping
;
1914 struct prio_tree_iter iter
;
1918 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1919 * from page cache lookup which is in HPAGE_SIZE units.
1921 address
= address
& huge_page_mask(h
);
1922 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
1923 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
1924 mapping
= (struct address_space
*)page_private(page
);
1926 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1927 /* Do not unmap the current VMA */
1928 if (iter_vma
== vma
)
1932 * Unmap the page from other VMAs without their own reserves.
1933 * They get marked to be SIGKILLed if they fault in these
1934 * areas. This is because a future no-page fault on this VMA
1935 * could insert a zeroed page instead of the data existing
1936 * from the time of fork. This would look like data corruption
1938 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
1939 unmap_hugepage_range(iter_vma
,
1940 address
, address
+ huge_page_size(h
),
1947 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1948 unsigned long address
, pte_t
*ptep
, pte_t pte
,
1949 struct page
*pagecache_page
)
1951 struct hstate
*h
= hstate_vma(vma
);
1952 struct page
*old_page
, *new_page
;
1954 int outside_reserve
= 0;
1956 old_page
= pte_page(pte
);
1959 /* If no-one else is actually using this page, avoid the copy
1960 * and just make the page writable */
1961 avoidcopy
= (page_count(old_page
) == 1);
1963 set_huge_ptep_writable(vma
, address
, ptep
);
1968 * If the process that created a MAP_PRIVATE mapping is about to
1969 * perform a COW due to a shared page count, attempt to satisfy
1970 * the allocation without using the existing reserves. The pagecache
1971 * page is used to determine if the reserve at this address was
1972 * consumed or not. If reserves were used, a partial faulted mapping
1973 * at the time of fork() could consume its reserves on COW instead
1974 * of the full address range.
1976 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
1977 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
1978 old_page
!= pagecache_page
)
1979 outside_reserve
= 1;
1981 page_cache_get(old_page
);
1982 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
1984 if (IS_ERR(new_page
)) {
1985 page_cache_release(old_page
);
1988 * If a process owning a MAP_PRIVATE mapping fails to COW,
1989 * it is due to references held by a child and an insufficient
1990 * huge page pool. To guarantee the original mappers
1991 * reliability, unmap the page from child processes. The child
1992 * may get SIGKILLed if it later faults.
1994 if (outside_reserve
) {
1995 BUG_ON(huge_pte_none(pte
));
1996 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
1997 BUG_ON(page_count(old_page
) != 1);
1998 BUG_ON(huge_pte_none(pte
));
1999 goto retry_avoidcopy
;
2004 return -PTR_ERR(new_page
);
2007 spin_unlock(&mm
->page_table_lock
);
2008 copy_huge_page(new_page
, old_page
, address
, vma
);
2009 __SetPageUptodate(new_page
);
2010 spin_lock(&mm
->page_table_lock
);
2012 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2013 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2015 huge_ptep_clear_flush(vma
, address
, ptep
);
2016 set_huge_pte_at(mm
, address
, ptep
,
2017 make_huge_pte(vma
, new_page
, 1));
2018 /* Make the old page be freed below */
2019 new_page
= old_page
;
2021 page_cache_release(new_page
);
2022 page_cache_release(old_page
);
2026 /* Return the pagecache page at a given address within a VMA */
2027 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2028 struct vm_area_struct
*vma
, unsigned long address
)
2030 struct address_space
*mapping
;
2033 mapping
= vma
->vm_file
->f_mapping
;
2034 idx
= vma_hugecache_offset(h
, vma
, address
);
2036 return find_lock_page(mapping
, idx
);
2040 * Return whether there is a pagecache page to back given address within VMA.
2041 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2043 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2044 struct vm_area_struct
*vma
, unsigned long address
)
2046 struct address_space
*mapping
;
2050 mapping
= vma
->vm_file
->f_mapping
;
2051 idx
= vma_hugecache_offset(h
, vma
, address
);
2053 page
= find_get_page(mapping
, idx
);
2056 return page
!= NULL
;
2059 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2060 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2062 struct hstate
*h
= hstate_vma(vma
);
2063 int ret
= VM_FAULT_SIGBUS
;
2067 struct address_space
*mapping
;
2071 * Currently, we are forced to kill the process in the event the
2072 * original mapper has unmapped pages from the child due to a failed
2073 * COW. Warn that such a situation has occured as it may not be obvious
2075 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2077 "PID %d killed due to inadequate hugepage pool\n",
2082 mapping
= vma
->vm_file
->f_mapping
;
2083 idx
= vma_hugecache_offset(h
, vma
, address
);
2086 * Use page lock to guard against racing truncation
2087 * before we get page_table_lock.
2090 page
= find_lock_page(mapping
, idx
);
2092 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2095 page
= alloc_huge_page(vma
, address
, 0);
2097 ret
= -PTR_ERR(page
);
2100 clear_huge_page(page
, address
, huge_page_size(h
));
2101 __SetPageUptodate(page
);
2103 if (vma
->vm_flags
& VM_MAYSHARE
) {
2105 struct inode
*inode
= mapping
->host
;
2107 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2115 spin_lock(&inode
->i_lock
);
2116 inode
->i_blocks
+= blocks_per_huge_page(h
);
2117 spin_unlock(&inode
->i_lock
);
2123 * If we are going to COW a private mapping later, we examine the
2124 * pending reservations for this page now. This will ensure that
2125 * any allocations necessary to record that reservation occur outside
2128 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2129 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2131 goto backout_unlocked
;
2134 spin_lock(&mm
->page_table_lock
);
2135 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2140 if (!huge_pte_none(huge_ptep_get(ptep
)))
2143 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2144 && (vma
->vm_flags
& VM_SHARED
)));
2145 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2147 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2148 /* Optimization, do the COW without a second fault */
2149 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2152 spin_unlock(&mm
->page_table_lock
);
2158 spin_unlock(&mm
->page_table_lock
);
2165 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2166 unsigned long address
, unsigned int flags
)
2171 struct page
*pagecache_page
= NULL
;
2172 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2173 struct hstate
*h
= hstate_vma(vma
);
2175 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2177 return VM_FAULT_OOM
;
2180 * Serialize hugepage allocation and instantiation, so that we don't
2181 * get spurious allocation failures if two CPUs race to instantiate
2182 * the same page in the page cache.
2184 mutex_lock(&hugetlb_instantiation_mutex
);
2185 entry
= huge_ptep_get(ptep
);
2186 if (huge_pte_none(entry
)) {
2187 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2194 * If we are going to COW the mapping later, we examine the pending
2195 * reservations for this page now. This will ensure that any
2196 * allocations necessary to record that reservation occur outside the
2197 * spinlock. For private mappings, we also lookup the pagecache
2198 * page now as it is used to determine if a reservation has been
2201 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2202 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2207 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2208 pagecache_page
= hugetlbfs_pagecache_page(h
,
2212 spin_lock(&mm
->page_table_lock
);
2213 /* Check for a racing update before calling hugetlb_cow */
2214 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2215 goto out_page_table_lock
;
2218 if (flags
& FAULT_FLAG_WRITE
) {
2219 if (!pte_write(entry
)) {
2220 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2222 goto out_page_table_lock
;
2224 entry
= pte_mkdirty(entry
);
2226 entry
= pte_mkyoung(entry
);
2227 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2228 flags
& FAULT_FLAG_WRITE
))
2229 update_mmu_cache(vma
, address
, entry
);
2231 out_page_table_lock
:
2232 spin_unlock(&mm
->page_table_lock
);
2234 if (pagecache_page
) {
2235 unlock_page(pagecache_page
);
2236 put_page(pagecache_page
);
2240 mutex_unlock(&hugetlb_instantiation_mutex
);
2245 /* Can be overriden by architectures */
2246 __attribute__((weak
)) struct page
*
2247 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2248 pud_t
*pud
, int write
)
2254 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2255 struct page
**pages
, struct vm_area_struct
**vmas
,
2256 unsigned long *position
, int *length
, int i
,
2259 unsigned long pfn_offset
;
2260 unsigned long vaddr
= *position
;
2261 int remainder
= *length
;
2262 struct hstate
*h
= hstate_vma(vma
);
2264 spin_lock(&mm
->page_table_lock
);
2265 while (vaddr
< vma
->vm_end
&& remainder
) {
2271 * Some archs (sparc64, sh*) have multiple pte_ts to
2272 * each hugepage. We have to make sure we get the
2273 * first, for the page indexing below to work.
2275 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2276 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2279 * When coredumping, it suits get_dump_page if we just return
2280 * an error where there's an empty slot with no huge pagecache
2281 * to back it. This way, we avoid allocating a hugepage, and
2282 * the sparse dumpfile avoids allocating disk blocks, but its
2283 * huge holes still show up with zeroes where they need to be.
2285 if (absent
&& (flags
& FOLL_DUMP
) &&
2286 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2292 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2295 spin_unlock(&mm
->page_table_lock
);
2296 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2297 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2298 spin_lock(&mm
->page_table_lock
);
2299 if (!(ret
& VM_FAULT_ERROR
))
2306 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2307 page
= pte_page(huge_ptep_get(pte
));
2310 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2321 if (vaddr
< vma
->vm_end
&& remainder
&&
2322 pfn_offset
< pages_per_huge_page(h
)) {
2324 * We use pfn_offset to avoid touching the pageframes
2325 * of this compound page.
2330 spin_unlock(&mm
->page_table_lock
);
2331 *length
= remainder
;
2334 return i
? i
: -EFAULT
;
2337 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2338 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2340 struct mm_struct
*mm
= vma
->vm_mm
;
2341 unsigned long start
= address
;
2344 struct hstate
*h
= hstate_vma(vma
);
2346 BUG_ON(address
>= end
);
2347 flush_cache_range(vma
, address
, end
);
2349 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2350 spin_lock(&mm
->page_table_lock
);
2351 for (; address
< end
; address
+= huge_page_size(h
)) {
2352 ptep
= huge_pte_offset(mm
, address
);
2355 if (huge_pmd_unshare(mm
, &address
, ptep
))
2357 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2358 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2359 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2360 set_huge_pte_at(mm
, address
, ptep
, pte
);
2363 spin_unlock(&mm
->page_table_lock
);
2364 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2366 flush_tlb_range(vma
, start
, end
);
2369 int hugetlb_reserve_pages(struct inode
*inode
,
2371 struct vm_area_struct
*vma
,
2375 struct hstate
*h
= hstate_inode(inode
);
2378 * Only apply hugepage reservation if asked. At fault time, an
2379 * attempt will be made for VM_NORESERVE to allocate a page
2380 * and filesystem quota without using reserves
2382 if (acctflag
& VM_NORESERVE
)
2386 * Shared mappings base their reservation on the number of pages that
2387 * are already allocated on behalf of the file. Private mappings need
2388 * to reserve the full area even if read-only as mprotect() may be
2389 * called to make the mapping read-write. Assume !vma is a shm mapping
2391 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2392 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2394 struct resv_map
*resv_map
= resv_map_alloc();
2400 set_vma_resv_map(vma
, resv_map
);
2401 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2407 /* There must be enough filesystem quota for the mapping */
2408 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2412 * Check enough hugepages are available for the reservation.
2413 * Hand back the quota if there are not
2415 ret
= hugetlb_acct_memory(h
, chg
);
2417 hugetlb_put_quota(inode
->i_mapping
, chg
);
2422 * Account for the reservations made. Shared mappings record regions
2423 * that have reservations as they are shared by multiple VMAs.
2424 * When the last VMA disappears, the region map says how much
2425 * the reservation was and the page cache tells how much of
2426 * the reservation was consumed. Private mappings are per-VMA and
2427 * only the consumed reservations are tracked. When the VMA
2428 * disappears, the original reservation is the VMA size and the
2429 * consumed reservations are stored in the map. Hence, nothing
2430 * else has to be done for private mappings here
2432 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2433 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2437 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2439 struct hstate
*h
= hstate_inode(inode
);
2440 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2442 spin_lock(&inode
->i_lock
);
2443 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
2444 spin_unlock(&inode
->i_lock
);
2446 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2447 hugetlb_acct_memory(h
, -(chg
- freed
));