2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
26 #include <asm/pgtable.h>
30 #include <linux/hugetlb.h>
31 #include <linux/hugetlb_cgroup.h>
32 #include <linux/node.h>
33 #include <linux/hugetlb_cgroup.h>
36 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
37 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
38 unsigned long hugepages_treat_as_movable
;
40 int hugetlb_max_hstate __read_mostly
;
41 unsigned int default_hstate_idx
;
42 struct hstate hstates
[HUGE_MAX_HSTATE
];
44 __initdata
LIST_HEAD(huge_boot_pages
);
46 /* for command line parsing */
47 static struct hstate
* __initdata parsed_hstate
;
48 static unsigned long __initdata default_hstate_max_huge_pages
;
49 static unsigned long __initdata default_hstate_size
;
52 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
54 DEFINE_SPINLOCK(hugetlb_lock
);
56 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
58 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
60 spin_unlock(&spool
->lock
);
62 /* If no pages are used, and no other handles to the subpool
63 * remain, free the subpool the subpool remain */
68 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
70 struct hugepage_subpool
*spool
;
72 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
76 spin_lock_init(&spool
->lock
);
78 spool
->max_hpages
= nr_blocks
;
79 spool
->used_hpages
= 0;
84 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
86 spin_lock(&spool
->lock
);
87 BUG_ON(!spool
->count
);
89 unlock_or_release_subpool(spool
);
92 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
100 spin_lock(&spool
->lock
);
101 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
102 spool
->used_hpages
+= delta
;
106 spin_unlock(&spool
->lock
);
111 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
117 spin_lock(&spool
->lock
);
118 spool
->used_hpages
-= delta
;
119 /* If hugetlbfs_put_super couldn't free spool due to
120 * an outstanding quota reference, free it now. */
121 unlock_or_release_subpool(spool
);
124 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
126 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
129 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
131 return subpool_inode(vma
->vm_file
->f_dentry
->d_inode
);
135 * Region tracking -- allows tracking of reservations and instantiated pages
136 * across the pages in a mapping.
138 * The region data structures are protected by a combination of the mmap_sem
139 * and the hugetlb_instantion_mutex. To access or modify a region the caller
140 * must either hold the mmap_sem for write, or the mmap_sem for read and
141 * the hugetlb_instantiation mutex:
143 * down_write(&mm->mmap_sem);
145 * down_read(&mm->mmap_sem);
146 * mutex_lock(&hugetlb_instantiation_mutex);
149 struct list_head link
;
154 static long region_add(struct list_head
*head
, long f
, long t
)
156 struct file_region
*rg
, *nrg
, *trg
;
158 /* Locate the region we are either in or before. */
159 list_for_each_entry(rg
, head
, link
)
163 /* Round our left edge to the current segment if it encloses us. */
167 /* Check for and consume any regions we now overlap with. */
169 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
170 if (&rg
->link
== head
)
175 /* If this area reaches higher then extend our area to
176 * include it completely. If this is not the first area
177 * which we intend to reuse, free it. */
190 static long region_chg(struct list_head
*head
, long f
, long t
)
192 struct file_region
*rg
, *nrg
;
195 /* Locate the region we are before or in. */
196 list_for_each_entry(rg
, head
, link
)
200 /* If we are below the current region then a new region is required.
201 * Subtle, allocate a new region at the position but make it zero
202 * size such that we can guarantee to record the reservation. */
203 if (&rg
->link
== head
|| t
< rg
->from
) {
204 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
209 INIT_LIST_HEAD(&nrg
->link
);
210 list_add(&nrg
->link
, rg
->link
.prev
);
215 /* Round our left edge to the current segment if it encloses us. */
220 /* Check for and consume any regions we now overlap with. */
221 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
222 if (&rg
->link
== head
)
227 /* We overlap with this area, if it extends further than
228 * us then we must extend ourselves. Account for its
229 * existing reservation. */
234 chg
-= rg
->to
- rg
->from
;
239 static long region_truncate(struct list_head
*head
, long end
)
241 struct file_region
*rg
, *trg
;
244 /* Locate the region we are either in or before. */
245 list_for_each_entry(rg
, head
, link
)
248 if (&rg
->link
== head
)
251 /* If we are in the middle of a region then adjust it. */
252 if (end
> rg
->from
) {
255 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
258 /* Drop any remaining regions. */
259 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
260 if (&rg
->link
== head
)
262 chg
+= rg
->to
- rg
->from
;
269 static long region_count(struct list_head
*head
, long f
, long t
)
271 struct file_region
*rg
;
274 /* Locate each segment we overlap with, and count that overlap. */
275 list_for_each_entry(rg
, head
, link
) {
284 seg_from
= max(rg
->from
, f
);
285 seg_to
= min(rg
->to
, t
);
287 chg
+= seg_to
- seg_from
;
294 * Convert the address within this vma to the page offset within
295 * the mapping, in pagecache page units; huge pages here.
297 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
298 struct vm_area_struct
*vma
, unsigned long address
)
300 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
301 (vma
->vm_pgoff
>> huge_page_order(h
));
304 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
305 unsigned long address
)
307 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
311 * Return the size of the pages allocated when backing a VMA. In the majority
312 * cases this will be same size as used by the page table entries.
314 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
316 struct hstate
*hstate
;
318 if (!is_vm_hugetlb_page(vma
))
321 hstate
= hstate_vma(vma
);
323 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
325 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
328 * Return the page size being used by the MMU to back a VMA. In the majority
329 * of cases, the page size used by the kernel matches the MMU size. On
330 * architectures where it differs, an architecture-specific version of this
331 * function is required.
333 #ifndef vma_mmu_pagesize
334 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
336 return vma_kernel_pagesize(vma
);
341 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
342 * bits of the reservation map pointer, which are always clear due to
345 #define HPAGE_RESV_OWNER (1UL << 0)
346 #define HPAGE_RESV_UNMAPPED (1UL << 1)
347 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
350 * These helpers are used to track how many pages are reserved for
351 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
352 * is guaranteed to have their future faults succeed.
354 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
355 * the reserve counters are updated with the hugetlb_lock held. It is safe
356 * to reset the VMA at fork() time as it is not in use yet and there is no
357 * chance of the global counters getting corrupted as a result of the values.
359 * The private mapping reservation is represented in a subtly different
360 * manner to a shared mapping. A shared mapping has a region map associated
361 * with the underlying file, this region map represents the backing file
362 * pages which have ever had a reservation assigned which this persists even
363 * after the page is instantiated. A private mapping has a region map
364 * associated with the original mmap which is attached to all VMAs which
365 * reference it, this region map represents those offsets which have consumed
366 * reservation ie. where pages have been instantiated.
368 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
370 return (unsigned long)vma
->vm_private_data
;
373 static void set_vma_private_data(struct vm_area_struct
*vma
,
376 vma
->vm_private_data
= (void *)value
;
381 struct list_head regions
;
384 static struct resv_map
*resv_map_alloc(void)
386 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
390 kref_init(&resv_map
->refs
);
391 INIT_LIST_HEAD(&resv_map
->regions
);
396 static void resv_map_release(struct kref
*ref
)
398 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
400 /* Clear out any active regions before we release the map. */
401 region_truncate(&resv_map
->regions
, 0);
405 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
407 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
408 if (!(vma
->vm_flags
& VM_MAYSHARE
))
409 return (struct resv_map
*)(get_vma_private_data(vma
) &
414 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
416 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
417 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
419 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
420 HPAGE_RESV_MASK
) | (unsigned long)map
);
423 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
425 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
426 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
428 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
431 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
433 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
435 return (get_vma_private_data(vma
) & flag
) != 0;
438 /* Decrement the reserved pages in the hugepage pool by one */
439 static void decrement_hugepage_resv_vma(struct hstate
*h
,
440 struct vm_area_struct
*vma
)
442 if (vma
->vm_flags
& VM_NORESERVE
)
445 if (vma
->vm_flags
& VM_MAYSHARE
) {
446 /* Shared mappings always use reserves */
447 h
->resv_huge_pages
--;
448 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
450 * Only the process that called mmap() has reserves for
453 h
->resv_huge_pages
--;
457 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
458 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
460 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
461 if (!(vma
->vm_flags
& VM_MAYSHARE
))
462 vma
->vm_private_data
= (void *)0;
465 /* Returns true if the VMA has associated reserve pages */
466 static int vma_has_reserves(struct vm_area_struct
*vma
)
468 if (vma
->vm_flags
& VM_MAYSHARE
)
470 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
475 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
478 struct hstate
*h
= page_hstate(src
);
479 struct page
*dst_base
= dst
;
480 struct page
*src_base
= src
;
482 for (i
= 0; i
< pages_per_huge_page(h
); ) {
484 copy_highpage(dst
, src
);
487 dst
= mem_map_next(dst
, dst_base
, i
);
488 src
= mem_map_next(src
, src_base
, i
);
492 void copy_huge_page(struct page
*dst
, struct page
*src
)
495 struct hstate
*h
= page_hstate(src
);
497 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
498 copy_gigantic_page(dst
, src
);
503 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
505 copy_highpage(dst
+ i
, src
+ i
);
509 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
511 int nid
= page_to_nid(page
);
512 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
513 h
->free_huge_pages
++;
514 h
->free_huge_pages_node
[nid
]++;
517 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
521 if (list_empty(&h
->hugepage_freelists
[nid
]))
523 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
524 list_move(&page
->lru
, &h
->hugepage_activelist
);
525 set_page_refcounted(page
);
526 h
->free_huge_pages
--;
527 h
->free_huge_pages_node
[nid
]--;
531 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
532 struct vm_area_struct
*vma
,
533 unsigned long address
, int avoid_reserve
)
535 struct page
*page
= NULL
;
536 struct mempolicy
*mpol
;
537 nodemask_t
*nodemask
;
538 struct zonelist
*zonelist
;
541 unsigned int cpuset_mems_cookie
;
544 cpuset_mems_cookie
= get_mems_allowed();
545 zonelist
= huge_zonelist(vma
, address
,
546 htlb_alloc_mask
, &mpol
, &nodemask
);
548 * A child process with MAP_PRIVATE mappings created by their parent
549 * have no page reserves. This check ensures that reservations are
550 * not "stolen". The child may still get SIGKILLed
552 if (!vma_has_reserves(vma
) &&
553 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
556 /* If reserves cannot be used, ensure enough pages are in the pool */
557 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
560 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
561 MAX_NR_ZONES
- 1, nodemask
) {
562 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
563 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
566 decrement_hugepage_resv_vma(h
, vma
);
573 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
582 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
586 VM_BUG_ON(h
->order
>= MAX_ORDER
);
589 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
590 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
591 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
592 1 << PG_referenced
| 1 << PG_dirty
|
593 1 << PG_active
| 1 << PG_reserved
|
594 1 << PG_private
| 1 << PG_writeback
);
596 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
597 set_compound_page_dtor(page
, NULL
);
598 set_page_refcounted(page
);
599 arch_release_hugepage(page
);
600 __free_pages(page
, huge_page_order(h
));
603 struct hstate
*size_to_hstate(unsigned long size
)
608 if (huge_page_size(h
) == size
)
614 static void free_huge_page(struct page
*page
)
617 * Can't pass hstate in here because it is called from the
618 * compound page destructor.
620 struct hstate
*h
= page_hstate(page
);
621 int nid
= page_to_nid(page
);
622 struct hugepage_subpool
*spool
=
623 (struct hugepage_subpool
*)page_private(page
);
625 set_page_private(page
, 0);
626 page
->mapping
= NULL
;
627 BUG_ON(page_count(page
));
628 BUG_ON(page_mapcount(page
));
630 spin_lock(&hugetlb_lock
);
631 hugetlb_cgroup_uncharge_page(hstate_index(h
),
632 pages_per_huge_page(h
), page
);
633 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
634 /* remove the page from active list */
635 list_del(&page
->lru
);
636 update_and_free_page(h
, page
);
637 h
->surplus_huge_pages
--;
638 h
->surplus_huge_pages_node
[nid
]--;
640 enqueue_huge_page(h
, page
);
642 spin_unlock(&hugetlb_lock
);
643 hugepage_subpool_put_pages(spool
, 1);
646 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
648 INIT_LIST_HEAD(&page
->lru
);
649 set_compound_page_dtor(page
, free_huge_page
);
650 spin_lock(&hugetlb_lock
);
651 set_hugetlb_cgroup(page
, NULL
);
653 h
->nr_huge_pages_node
[nid
]++;
654 spin_unlock(&hugetlb_lock
);
655 put_page(page
); /* free it into the hugepage allocator */
658 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
661 int nr_pages
= 1 << order
;
662 struct page
*p
= page
+ 1;
664 /* we rely on prep_new_huge_page to set the destructor */
665 set_compound_order(page
, order
);
667 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
669 set_page_count(p
, 0);
670 p
->first_page
= page
;
674 int PageHuge(struct page
*page
)
676 compound_page_dtor
*dtor
;
678 if (!PageCompound(page
))
681 page
= compound_head(page
);
682 dtor
= get_compound_page_dtor(page
);
684 return dtor
== free_huge_page
;
686 EXPORT_SYMBOL_GPL(PageHuge
);
688 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
692 if (h
->order
>= MAX_ORDER
)
695 page
= alloc_pages_exact_node(nid
,
696 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
697 __GFP_REPEAT
|__GFP_NOWARN
,
700 if (arch_prepare_hugepage(page
)) {
701 __free_pages(page
, huge_page_order(h
));
704 prep_new_huge_page(h
, page
, nid
);
711 * common helper functions for hstate_next_node_to_{alloc|free}.
712 * We may have allocated or freed a huge page based on a different
713 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
714 * be outside of *nodes_allowed. Ensure that we use an allowed
715 * node for alloc or free.
717 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
719 nid
= next_node(nid
, *nodes_allowed
);
720 if (nid
== MAX_NUMNODES
)
721 nid
= first_node(*nodes_allowed
);
722 VM_BUG_ON(nid
>= MAX_NUMNODES
);
727 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
729 if (!node_isset(nid
, *nodes_allowed
))
730 nid
= next_node_allowed(nid
, nodes_allowed
);
735 * returns the previously saved node ["this node"] from which to
736 * allocate a persistent huge page for the pool and advance the
737 * next node from which to allocate, handling wrap at end of node
740 static int hstate_next_node_to_alloc(struct hstate
*h
,
741 nodemask_t
*nodes_allowed
)
745 VM_BUG_ON(!nodes_allowed
);
747 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
748 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
753 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
760 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
761 next_nid
= start_nid
;
764 page
= alloc_fresh_huge_page_node(h
, next_nid
);
769 next_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
770 } while (next_nid
!= start_nid
);
773 count_vm_event(HTLB_BUDDY_PGALLOC
);
775 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
781 * helper for free_pool_huge_page() - return the previously saved
782 * node ["this node"] from which to free a huge page. Advance the
783 * next node id whether or not we find a free huge page to free so
784 * that the next attempt to free addresses the next node.
786 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
790 VM_BUG_ON(!nodes_allowed
);
792 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
793 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
799 * Free huge page from pool from next node to free.
800 * Attempt to keep persistent huge pages more or less
801 * balanced over allowed nodes.
802 * Called with hugetlb_lock locked.
804 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
811 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
812 next_nid
= start_nid
;
816 * If we're returning unused surplus pages, only examine
817 * nodes with surplus pages.
819 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
820 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
822 list_entry(h
->hugepage_freelists
[next_nid
].next
,
824 list_del(&page
->lru
);
825 h
->free_huge_pages
--;
826 h
->free_huge_pages_node
[next_nid
]--;
828 h
->surplus_huge_pages
--;
829 h
->surplus_huge_pages_node
[next_nid
]--;
831 update_and_free_page(h
, page
);
835 next_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
836 } while (next_nid
!= start_nid
);
841 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
846 if (h
->order
>= MAX_ORDER
)
850 * Assume we will successfully allocate the surplus page to
851 * prevent racing processes from causing the surplus to exceed
854 * This however introduces a different race, where a process B
855 * tries to grow the static hugepage pool while alloc_pages() is
856 * called by process A. B will only examine the per-node
857 * counters in determining if surplus huge pages can be
858 * converted to normal huge pages in adjust_pool_surplus(). A
859 * won't be able to increment the per-node counter, until the
860 * lock is dropped by B, but B doesn't drop hugetlb_lock until
861 * no more huge pages can be converted from surplus to normal
862 * state (and doesn't try to convert again). Thus, we have a
863 * case where a surplus huge page exists, the pool is grown, and
864 * the surplus huge page still exists after, even though it
865 * should just have been converted to a normal huge page. This
866 * does not leak memory, though, as the hugepage will be freed
867 * once it is out of use. It also does not allow the counters to
868 * go out of whack in adjust_pool_surplus() as we don't modify
869 * the node values until we've gotten the hugepage and only the
870 * per-node value is checked there.
872 spin_lock(&hugetlb_lock
);
873 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
874 spin_unlock(&hugetlb_lock
);
878 h
->surplus_huge_pages
++;
880 spin_unlock(&hugetlb_lock
);
882 if (nid
== NUMA_NO_NODE
)
883 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
884 __GFP_REPEAT
|__GFP_NOWARN
,
887 page
= alloc_pages_exact_node(nid
,
888 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
889 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
891 if (page
&& arch_prepare_hugepage(page
)) {
892 __free_pages(page
, huge_page_order(h
));
896 spin_lock(&hugetlb_lock
);
898 INIT_LIST_HEAD(&page
->lru
);
899 r_nid
= page_to_nid(page
);
900 set_compound_page_dtor(page
, free_huge_page
);
901 set_hugetlb_cgroup(page
, NULL
);
903 * We incremented the global counters already
905 h
->nr_huge_pages_node
[r_nid
]++;
906 h
->surplus_huge_pages_node
[r_nid
]++;
907 __count_vm_event(HTLB_BUDDY_PGALLOC
);
910 h
->surplus_huge_pages
--;
911 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
913 spin_unlock(&hugetlb_lock
);
919 * This allocation function is useful in the context where vma is irrelevant.
920 * E.g. soft-offlining uses this function because it only cares physical
921 * address of error page.
923 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
927 spin_lock(&hugetlb_lock
);
928 page
= dequeue_huge_page_node(h
, nid
);
929 spin_unlock(&hugetlb_lock
);
932 page
= alloc_buddy_huge_page(h
, nid
);
934 spin_lock(&hugetlb_lock
);
935 list_move(&page
->lru
, &h
->hugepage_activelist
);
936 spin_unlock(&hugetlb_lock
);
944 * Increase the hugetlb pool such that it can accommodate a reservation
947 static int gather_surplus_pages(struct hstate
*h
, int delta
)
949 struct list_head surplus_list
;
950 struct page
*page
, *tmp
;
952 int needed
, allocated
;
953 bool alloc_ok
= true;
955 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
957 h
->resv_huge_pages
+= delta
;
962 INIT_LIST_HEAD(&surplus_list
);
966 spin_unlock(&hugetlb_lock
);
967 for (i
= 0; i
< needed
; i
++) {
968 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
973 list_add(&page
->lru
, &surplus_list
);
978 * After retaking hugetlb_lock, we need to recalculate 'needed'
979 * because either resv_huge_pages or free_huge_pages may have changed.
981 spin_lock(&hugetlb_lock
);
982 needed
= (h
->resv_huge_pages
+ delta
) -
983 (h
->free_huge_pages
+ allocated
);
988 * We were not able to allocate enough pages to
989 * satisfy the entire reservation so we free what
990 * we've allocated so far.
995 * The surplus_list now contains _at_least_ the number of extra pages
996 * needed to accommodate the reservation. Add the appropriate number
997 * of pages to the hugetlb pool and free the extras back to the buddy
998 * allocator. Commit the entire reservation here to prevent another
999 * process from stealing the pages as they are added to the pool but
1000 * before they are reserved.
1002 needed
+= allocated
;
1003 h
->resv_huge_pages
+= delta
;
1006 /* Free the needed pages to the hugetlb pool */
1007 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1011 * This page is now managed by the hugetlb allocator and has
1012 * no users -- drop the buddy allocator's reference.
1014 put_page_testzero(page
);
1015 VM_BUG_ON(page_count(page
));
1016 enqueue_huge_page(h
, page
);
1019 spin_unlock(&hugetlb_lock
);
1021 /* Free unnecessary surplus pages to the buddy allocator */
1022 if (!list_empty(&surplus_list
)) {
1023 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1027 spin_lock(&hugetlb_lock
);
1033 * When releasing a hugetlb pool reservation, any surplus pages that were
1034 * allocated to satisfy the reservation must be explicitly freed if they were
1036 * Called with hugetlb_lock held.
1038 static void return_unused_surplus_pages(struct hstate
*h
,
1039 unsigned long unused_resv_pages
)
1041 unsigned long nr_pages
;
1043 /* Uncommit the reservation */
1044 h
->resv_huge_pages
-= unused_resv_pages
;
1046 /* Cannot return gigantic pages currently */
1047 if (h
->order
>= MAX_ORDER
)
1050 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1053 * We want to release as many surplus pages as possible, spread
1054 * evenly across all nodes with memory. Iterate across these nodes
1055 * until we can no longer free unreserved surplus pages. This occurs
1056 * when the nodes with surplus pages have no free pages.
1057 * free_pool_huge_page() will balance the the freed pages across the
1058 * on-line nodes with memory and will handle the hstate accounting.
1060 while (nr_pages
--) {
1061 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
1067 * Determine if the huge page at addr within the vma has an associated
1068 * reservation. Where it does not we will need to logically increase
1069 * reservation and actually increase subpool usage before an allocation
1070 * can occur. Where any new reservation would be required the
1071 * reservation change is prepared, but not committed. Once the page
1072 * has been allocated from the subpool and instantiated the change should
1073 * be committed via vma_commit_reservation. No action is required on
1076 static long vma_needs_reservation(struct hstate
*h
,
1077 struct vm_area_struct
*vma
, unsigned long addr
)
1079 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1080 struct inode
*inode
= mapping
->host
;
1082 if (vma
->vm_flags
& VM_MAYSHARE
) {
1083 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1084 return region_chg(&inode
->i_mapping
->private_list
,
1087 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1092 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1093 struct resv_map
*reservations
= vma_resv_map(vma
);
1095 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1101 static void vma_commit_reservation(struct hstate
*h
,
1102 struct vm_area_struct
*vma
, unsigned long addr
)
1104 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1105 struct inode
*inode
= mapping
->host
;
1107 if (vma
->vm_flags
& VM_MAYSHARE
) {
1108 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1109 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1111 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1112 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1113 struct resv_map
*reservations
= vma_resv_map(vma
);
1115 /* Mark this page used in the map. */
1116 region_add(&reservations
->regions
, idx
, idx
+ 1);
1120 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1121 unsigned long addr
, int avoid_reserve
)
1123 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1124 struct hstate
*h
= hstate_vma(vma
);
1128 struct hugetlb_cgroup
*h_cg
;
1130 idx
= hstate_index(h
);
1132 * Processes that did not create the mapping will have no
1133 * reserves and will not have accounted against subpool
1134 * limit. Check that the subpool limit can be made before
1135 * satisfying the allocation MAP_NORESERVE mappings may also
1136 * need pages and subpool limit allocated allocated if no reserve
1139 chg
= vma_needs_reservation(h
, vma
, addr
);
1141 return ERR_PTR(-ENOMEM
);
1143 if (hugepage_subpool_get_pages(spool
, chg
))
1144 return ERR_PTR(-ENOSPC
);
1146 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1148 hugepage_subpool_put_pages(spool
, chg
);
1149 return ERR_PTR(-ENOSPC
);
1151 spin_lock(&hugetlb_lock
);
1152 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1153 spin_unlock(&hugetlb_lock
);
1156 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1158 hugetlb_cgroup_uncharge_cgroup(idx
,
1159 pages_per_huge_page(h
),
1161 hugepage_subpool_put_pages(spool
, chg
);
1162 return ERR_PTR(-ENOSPC
);
1164 spin_lock(&hugetlb_lock
);
1165 list_move(&page
->lru
, &h
->hugepage_activelist
);
1166 spin_unlock(&hugetlb_lock
);
1169 set_page_private(page
, (unsigned long)spool
);
1171 vma_commit_reservation(h
, vma
, addr
);
1172 /* update page cgroup details */
1173 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1177 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1179 struct huge_bootmem_page
*m
;
1180 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1185 addr
= __alloc_bootmem_node_nopanic(
1186 NODE_DATA(hstate_next_node_to_alloc(h
,
1187 &node_states
[N_HIGH_MEMORY
])),
1188 huge_page_size(h
), huge_page_size(h
), 0);
1192 * Use the beginning of the huge page to store the
1193 * huge_bootmem_page struct (until gather_bootmem
1194 * puts them into the mem_map).
1204 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1205 /* Put them into a private list first because mem_map is not up yet */
1206 list_add(&m
->list
, &huge_boot_pages
);
1211 static void prep_compound_huge_page(struct page
*page
, int order
)
1213 if (unlikely(order
> (MAX_ORDER
- 1)))
1214 prep_compound_gigantic_page(page
, order
);
1216 prep_compound_page(page
, order
);
1219 /* Put bootmem huge pages into the standard lists after mem_map is up */
1220 static void __init
gather_bootmem_prealloc(void)
1222 struct huge_bootmem_page
*m
;
1224 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1225 struct hstate
*h
= m
->hstate
;
1228 #ifdef CONFIG_HIGHMEM
1229 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1230 free_bootmem_late((unsigned long)m
,
1231 sizeof(struct huge_bootmem_page
));
1233 page
= virt_to_page(m
);
1235 __ClearPageReserved(page
);
1236 WARN_ON(page_count(page
) != 1);
1237 prep_compound_huge_page(page
, h
->order
);
1238 prep_new_huge_page(h
, page
, page_to_nid(page
));
1240 * If we had gigantic hugepages allocated at boot time, we need
1241 * to restore the 'stolen' pages to totalram_pages in order to
1242 * fix confusing memory reports from free(1) and another
1243 * side-effects, like CommitLimit going negative.
1245 if (h
->order
> (MAX_ORDER
- 1))
1246 totalram_pages
+= 1 << h
->order
;
1250 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1254 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1255 if (h
->order
>= MAX_ORDER
) {
1256 if (!alloc_bootmem_huge_page(h
))
1258 } else if (!alloc_fresh_huge_page(h
,
1259 &node_states
[N_HIGH_MEMORY
]))
1262 h
->max_huge_pages
= i
;
1265 static void __init
hugetlb_init_hstates(void)
1269 for_each_hstate(h
) {
1270 /* oversize hugepages were init'ed in early boot */
1271 if (h
->order
< MAX_ORDER
)
1272 hugetlb_hstate_alloc_pages(h
);
1276 static char * __init
memfmt(char *buf
, unsigned long n
)
1278 if (n
>= (1UL << 30))
1279 sprintf(buf
, "%lu GB", n
>> 30);
1280 else if (n
>= (1UL << 20))
1281 sprintf(buf
, "%lu MB", n
>> 20);
1283 sprintf(buf
, "%lu KB", n
>> 10);
1287 static void __init
report_hugepages(void)
1291 for_each_hstate(h
) {
1293 printk(KERN_INFO
"HugeTLB registered %s page size, "
1294 "pre-allocated %ld pages\n",
1295 memfmt(buf
, huge_page_size(h
)),
1296 h
->free_huge_pages
);
1300 #ifdef CONFIG_HIGHMEM
1301 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1302 nodemask_t
*nodes_allowed
)
1306 if (h
->order
>= MAX_ORDER
)
1309 for_each_node_mask(i
, *nodes_allowed
) {
1310 struct page
*page
, *next
;
1311 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1312 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1313 if (count
>= h
->nr_huge_pages
)
1315 if (PageHighMem(page
))
1317 list_del(&page
->lru
);
1318 update_and_free_page(h
, page
);
1319 h
->free_huge_pages
--;
1320 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1325 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1326 nodemask_t
*nodes_allowed
)
1332 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1333 * balanced by operating on them in a round-robin fashion.
1334 * Returns 1 if an adjustment was made.
1336 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1339 int start_nid
, next_nid
;
1342 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1345 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1347 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1348 next_nid
= start_nid
;
1354 * To shrink on this node, there must be a surplus page
1356 if (!h
->surplus_huge_pages_node
[nid
]) {
1357 next_nid
= hstate_next_node_to_alloc(h
,
1364 * Surplus cannot exceed the total number of pages
1366 if (h
->surplus_huge_pages_node
[nid
] >=
1367 h
->nr_huge_pages_node
[nid
]) {
1368 next_nid
= hstate_next_node_to_free(h
,
1374 h
->surplus_huge_pages
+= delta
;
1375 h
->surplus_huge_pages_node
[nid
] += delta
;
1378 } while (next_nid
!= start_nid
);
1383 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1384 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1385 nodemask_t
*nodes_allowed
)
1387 unsigned long min_count
, ret
;
1389 if (h
->order
>= MAX_ORDER
)
1390 return h
->max_huge_pages
;
1393 * Increase the pool size
1394 * First take pages out of surplus state. Then make up the
1395 * remaining difference by allocating fresh huge pages.
1397 * We might race with alloc_buddy_huge_page() here and be unable
1398 * to convert a surplus huge page to a normal huge page. That is
1399 * not critical, though, it just means the overall size of the
1400 * pool might be one hugepage larger than it needs to be, but
1401 * within all the constraints specified by the sysctls.
1403 spin_lock(&hugetlb_lock
);
1404 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1405 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1409 while (count
> persistent_huge_pages(h
)) {
1411 * If this allocation races such that we no longer need the
1412 * page, free_huge_page will handle it by freeing the page
1413 * and reducing the surplus.
1415 spin_unlock(&hugetlb_lock
);
1416 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1417 spin_lock(&hugetlb_lock
);
1421 /* Bail for signals. Probably ctrl-c from user */
1422 if (signal_pending(current
))
1427 * Decrease the pool size
1428 * First return free pages to the buddy allocator (being careful
1429 * to keep enough around to satisfy reservations). Then place
1430 * pages into surplus state as needed so the pool will shrink
1431 * to the desired size as pages become free.
1433 * By placing pages into the surplus state independent of the
1434 * overcommit value, we are allowing the surplus pool size to
1435 * exceed overcommit. There are few sane options here. Since
1436 * alloc_buddy_huge_page() is checking the global counter,
1437 * though, we'll note that we're not allowed to exceed surplus
1438 * and won't grow the pool anywhere else. Not until one of the
1439 * sysctls are changed, or the surplus pages go out of use.
1441 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1442 min_count
= max(count
, min_count
);
1443 try_to_free_low(h
, min_count
, nodes_allowed
);
1444 while (min_count
< persistent_huge_pages(h
)) {
1445 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1448 while (count
< persistent_huge_pages(h
)) {
1449 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1453 ret
= persistent_huge_pages(h
);
1454 spin_unlock(&hugetlb_lock
);
1458 #define HSTATE_ATTR_RO(_name) \
1459 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1461 #define HSTATE_ATTR(_name) \
1462 static struct kobj_attribute _name##_attr = \
1463 __ATTR(_name, 0644, _name##_show, _name##_store)
1465 static struct kobject
*hugepages_kobj
;
1466 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1468 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1470 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1474 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1475 if (hstate_kobjs
[i
] == kobj
) {
1477 *nidp
= NUMA_NO_NODE
;
1481 return kobj_to_node_hstate(kobj
, nidp
);
1484 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1485 struct kobj_attribute
*attr
, char *buf
)
1488 unsigned long nr_huge_pages
;
1491 h
= kobj_to_hstate(kobj
, &nid
);
1492 if (nid
== NUMA_NO_NODE
)
1493 nr_huge_pages
= h
->nr_huge_pages
;
1495 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1497 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1500 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1501 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1502 const char *buf
, size_t len
)
1506 unsigned long count
;
1508 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1510 err
= strict_strtoul(buf
, 10, &count
);
1514 h
= kobj_to_hstate(kobj
, &nid
);
1515 if (h
->order
>= MAX_ORDER
) {
1520 if (nid
== NUMA_NO_NODE
) {
1522 * global hstate attribute
1524 if (!(obey_mempolicy
&&
1525 init_nodemask_of_mempolicy(nodes_allowed
))) {
1526 NODEMASK_FREE(nodes_allowed
);
1527 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1529 } else if (nodes_allowed
) {
1531 * per node hstate attribute: adjust count to global,
1532 * but restrict alloc/free to the specified node.
1534 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1535 init_nodemask_of_node(nodes_allowed
, nid
);
1537 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1539 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1541 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1542 NODEMASK_FREE(nodes_allowed
);
1546 NODEMASK_FREE(nodes_allowed
);
1550 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1551 struct kobj_attribute
*attr
, char *buf
)
1553 return nr_hugepages_show_common(kobj
, attr
, buf
);
1556 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1557 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1559 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1561 HSTATE_ATTR(nr_hugepages
);
1566 * hstate attribute for optionally mempolicy-based constraint on persistent
1567 * huge page alloc/free.
1569 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1570 struct kobj_attribute
*attr
, char *buf
)
1572 return nr_hugepages_show_common(kobj
, attr
, buf
);
1575 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1576 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1578 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1580 HSTATE_ATTR(nr_hugepages_mempolicy
);
1584 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1585 struct kobj_attribute
*attr
, char *buf
)
1587 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1588 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1591 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1592 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1595 unsigned long input
;
1596 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1598 if (h
->order
>= MAX_ORDER
)
1601 err
= strict_strtoul(buf
, 10, &input
);
1605 spin_lock(&hugetlb_lock
);
1606 h
->nr_overcommit_huge_pages
= input
;
1607 spin_unlock(&hugetlb_lock
);
1611 HSTATE_ATTR(nr_overcommit_hugepages
);
1613 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1614 struct kobj_attribute
*attr
, char *buf
)
1617 unsigned long free_huge_pages
;
1620 h
= kobj_to_hstate(kobj
, &nid
);
1621 if (nid
== NUMA_NO_NODE
)
1622 free_huge_pages
= h
->free_huge_pages
;
1624 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1626 return sprintf(buf
, "%lu\n", free_huge_pages
);
1628 HSTATE_ATTR_RO(free_hugepages
);
1630 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1631 struct kobj_attribute
*attr
, char *buf
)
1633 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1634 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1636 HSTATE_ATTR_RO(resv_hugepages
);
1638 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1639 struct kobj_attribute
*attr
, char *buf
)
1642 unsigned long surplus_huge_pages
;
1645 h
= kobj_to_hstate(kobj
, &nid
);
1646 if (nid
== NUMA_NO_NODE
)
1647 surplus_huge_pages
= h
->surplus_huge_pages
;
1649 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1651 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1653 HSTATE_ATTR_RO(surplus_hugepages
);
1655 static struct attribute
*hstate_attrs
[] = {
1656 &nr_hugepages_attr
.attr
,
1657 &nr_overcommit_hugepages_attr
.attr
,
1658 &free_hugepages_attr
.attr
,
1659 &resv_hugepages_attr
.attr
,
1660 &surplus_hugepages_attr
.attr
,
1662 &nr_hugepages_mempolicy_attr
.attr
,
1667 static struct attribute_group hstate_attr_group
= {
1668 .attrs
= hstate_attrs
,
1671 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1672 struct kobject
**hstate_kobjs
,
1673 struct attribute_group
*hstate_attr_group
)
1676 int hi
= hstate_index(h
);
1678 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1679 if (!hstate_kobjs
[hi
])
1682 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1684 kobject_put(hstate_kobjs
[hi
]);
1689 static void __init
hugetlb_sysfs_init(void)
1694 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1695 if (!hugepages_kobj
)
1698 for_each_hstate(h
) {
1699 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1700 hstate_kobjs
, &hstate_attr_group
);
1702 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1710 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1711 * with node devices in node_devices[] using a parallel array. The array
1712 * index of a node device or _hstate == node id.
1713 * This is here to avoid any static dependency of the node device driver, in
1714 * the base kernel, on the hugetlb module.
1716 struct node_hstate
{
1717 struct kobject
*hugepages_kobj
;
1718 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1720 struct node_hstate node_hstates
[MAX_NUMNODES
];
1723 * A subset of global hstate attributes for node devices
1725 static struct attribute
*per_node_hstate_attrs
[] = {
1726 &nr_hugepages_attr
.attr
,
1727 &free_hugepages_attr
.attr
,
1728 &surplus_hugepages_attr
.attr
,
1732 static struct attribute_group per_node_hstate_attr_group
= {
1733 .attrs
= per_node_hstate_attrs
,
1737 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1738 * Returns node id via non-NULL nidp.
1740 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1744 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1745 struct node_hstate
*nhs
= &node_hstates
[nid
];
1747 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1748 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1760 * Unregister hstate attributes from a single node device.
1761 * No-op if no hstate attributes attached.
1763 void hugetlb_unregister_node(struct node
*node
)
1766 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1768 if (!nhs
->hugepages_kobj
)
1769 return; /* no hstate attributes */
1771 for_each_hstate(h
) {
1772 int idx
= hstate_index(h
);
1773 if (nhs
->hstate_kobjs
[idx
]) {
1774 kobject_put(nhs
->hstate_kobjs
[idx
]);
1775 nhs
->hstate_kobjs
[idx
] = NULL
;
1779 kobject_put(nhs
->hugepages_kobj
);
1780 nhs
->hugepages_kobj
= NULL
;
1784 * hugetlb module exit: unregister hstate attributes from node devices
1787 static void hugetlb_unregister_all_nodes(void)
1792 * disable node device registrations.
1794 register_hugetlbfs_with_node(NULL
, NULL
);
1797 * remove hstate attributes from any nodes that have them.
1799 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1800 hugetlb_unregister_node(&node_devices
[nid
]);
1804 * Register hstate attributes for a single node device.
1805 * No-op if attributes already registered.
1807 void hugetlb_register_node(struct node
*node
)
1810 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1813 if (nhs
->hugepages_kobj
)
1814 return; /* already allocated */
1816 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1818 if (!nhs
->hugepages_kobj
)
1821 for_each_hstate(h
) {
1822 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1824 &per_node_hstate_attr_group
);
1826 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1828 h
->name
, node
->dev
.id
);
1829 hugetlb_unregister_node(node
);
1836 * hugetlb init time: register hstate attributes for all registered node
1837 * devices of nodes that have memory. All on-line nodes should have
1838 * registered their associated device by this time.
1840 static void hugetlb_register_all_nodes(void)
1844 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1845 struct node
*node
= &node_devices
[nid
];
1846 if (node
->dev
.id
== nid
)
1847 hugetlb_register_node(node
);
1851 * Let the node device driver know we're here so it can
1852 * [un]register hstate attributes on node hotplug.
1854 register_hugetlbfs_with_node(hugetlb_register_node
,
1855 hugetlb_unregister_node
);
1857 #else /* !CONFIG_NUMA */
1859 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1867 static void hugetlb_unregister_all_nodes(void) { }
1869 static void hugetlb_register_all_nodes(void) { }
1873 static void __exit
hugetlb_exit(void)
1877 hugetlb_unregister_all_nodes();
1879 for_each_hstate(h
) {
1880 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1883 kobject_put(hugepages_kobj
);
1885 module_exit(hugetlb_exit
);
1887 static int __init
hugetlb_init(void)
1889 /* Some platform decide whether they support huge pages at boot
1890 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1891 * there is no such support
1893 if (HPAGE_SHIFT
== 0)
1896 if (!size_to_hstate(default_hstate_size
)) {
1897 default_hstate_size
= HPAGE_SIZE
;
1898 if (!size_to_hstate(default_hstate_size
))
1899 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1901 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1902 if (default_hstate_max_huge_pages
)
1903 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1905 hugetlb_init_hstates();
1907 gather_bootmem_prealloc();
1911 hugetlb_sysfs_init();
1913 hugetlb_register_all_nodes();
1917 module_init(hugetlb_init
);
1919 /* Should be called on processing a hugepagesz=... option */
1920 void __init
hugetlb_add_hstate(unsigned order
)
1925 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1926 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1929 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1931 h
= &hstates
[hugetlb_max_hstate
++];
1933 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1934 h
->nr_huge_pages
= 0;
1935 h
->free_huge_pages
= 0;
1936 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1937 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1938 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1939 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1940 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1941 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1942 huge_page_size(h
)/1024);
1944 * Add cgroup control files only if the huge page consists
1945 * of more than two normal pages. This is because we use
1946 * page[2].lru.next for storing cgoup details.
1948 if (order
>= HUGETLB_CGROUP_MIN_ORDER
)
1949 hugetlb_cgroup_file_init(hugetlb_max_hstate
- 1);
1954 static int __init
hugetlb_nrpages_setup(char *s
)
1957 static unsigned long *last_mhp
;
1960 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1961 * so this hugepages= parameter goes to the "default hstate".
1963 if (!hugetlb_max_hstate
)
1964 mhp
= &default_hstate_max_huge_pages
;
1966 mhp
= &parsed_hstate
->max_huge_pages
;
1968 if (mhp
== last_mhp
) {
1969 printk(KERN_WARNING
"hugepages= specified twice without "
1970 "interleaving hugepagesz=, ignoring\n");
1974 if (sscanf(s
, "%lu", mhp
) <= 0)
1978 * Global state is always initialized later in hugetlb_init.
1979 * But we need to allocate >= MAX_ORDER hstates here early to still
1980 * use the bootmem allocator.
1982 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1983 hugetlb_hstate_alloc_pages(parsed_hstate
);
1989 __setup("hugepages=", hugetlb_nrpages_setup
);
1991 static int __init
hugetlb_default_setup(char *s
)
1993 default_hstate_size
= memparse(s
, &s
);
1996 __setup("default_hugepagesz=", hugetlb_default_setup
);
1998 static unsigned int cpuset_mems_nr(unsigned int *array
)
2001 unsigned int nr
= 0;
2003 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2009 #ifdef CONFIG_SYSCTL
2010 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2011 struct ctl_table
*table
, int write
,
2012 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2014 struct hstate
*h
= &default_hstate
;
2018 tmp
= h
->max_huge_pages
;
2020 if (write
&& h
->order
>= MAX_ORDER
)
2024 table
->maxlen
= sizeof(unsigned long);
2025 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2030 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2031 GFP_KERNEL
| __GFP_NORETRY
);
2032 if (!(obey_mempolicy
&&
2033 init_nodemask_of_mempolicy(nodes_allowed
))) {
2034 NODEMASK_FREE(nodes_allowed
);
2035 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
2037 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2039 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
2040 NODEMASK_FREE(nodes_allowed
);
2046 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2047 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2050 return hugetlb_sysctl_handler_common(false, table
, write
,
2051 buffer
, length
, ppos
);
2055 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2056 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2058 return hugetlb_sysctl_handler_common(true, table
, write
,
2059 buffer
, length
, ppos
);
2061 #endif /* CONFIG_NUMA */
2063 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2064 void __user
*buffer
,
2065 size_t *length
, loff_t
*ppos
)
2067 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2068 if (hugepages_treat_as_movable
)
2069 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2071 htlb_alloc_mask
= GFP_HIGHUSER
;
2075 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2076 void __user
*buffer
,
2077 size_t *length
, loff_t
*ppos
)
2079 struct hstate
*h
= &default_hstate
;
2083 tmp
= h
->nr_overcommit_huge_pages
;
2085 if (write
&& h
->order
>= MAX_ORDER
)
2089 table
->maxlen
= sizeof(unsigned long);
2090 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2095 spin_lock(&hugetlb_lock
);
2096 h
->nr_overcommit_huge_pages
= tmp
;
2097 spin_unlock(&hugetlb_lock
);
2103 #endif /* CONFIG_SYSCTL */
2105 void hugetlb_report_meminfo(struct seq_file
*m
)
2107 struct hstate
*h
= &default_hstate
;
2109 "HugePages_Total: %5lu\n"
2110 "HugePages_Free: %5lu\n"
2111 "HugePages_Rsvd: %5lu\n"
2112 "HugePages_Surp: %5lu\n"
2113 "Hugepagesize: %8lu kB\n",
2117 h
->surplus_huge_pages
,
2118 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2121 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2123 struct hstate
*h
= &default_hstate
;
2125 "Node %d HugePages_Total: %5u\n"
2126 "Node %d HugePages_Free: %5u\n"
2127 "Node %d HugePages_Surp: %5u\n",
2128 nid
, h
->nr_huge_pages_node
[nid
],
2129 nid
, h
->free_huge_pages_node
[nid
],
2130 nid
, h
->surplus_huge_pages_node
[nid
]);
2133 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2134 unsigned long hugetlb_total_pages(void)
2136 struct hstate
*h
= &default_hstate
;
2137 return h
->nr_huge_pages
* pages_per_huge_page(h
);
2140 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2144 spin_lock(&hugetlb_lock
);
2146 * When cpuset is configured, it breaks the strict hugetlb page
2147 * reservation as the accounting is done on a global variable. Such
2148 * reservation is completely rubbish in the presence of cpuset because
2149 * the reservation is not checked against page availability for the
2150 * current cpuset. Application can still potentially OOM'ed by kernel
2151 * with lack of free htlb page in cpuset that the task is in.
2152 * Attempt to enforce strict accounting with cpuset is almost
2153 * impossible (or too ugly) because cpuset is too fluid that
2154 * task or memory node can be dynamically moved between cpusets.
2156 * The change of semantics for shared hugetlb mapping with cpuset is
2157 * undesirable. However, in order to preserve some of the semantics,
2158 * we fall back to check against current free page availability as
2159 * a best attempt and hopefully to minimize the impact of changing
2160 * semantics that cpuset has.
2163 if (gather_surplus_pages(h
, delta
) < 0)
2166 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2167 return_unused_surplus_pages(h
, delta
);
2174 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2177 spin_unlock(&hugetlb_lock
);
2181 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2183 struct resv_map
*reservations
= vma_resv_map(vma
);
2186 * This new VMA should share its siblings reservation map if present.
2187 * The VMA will only ever have a valid reservation map pointer where
2188 * it is being copied for another still existing VMA. As that VMA
2189 * has a reference to the reservation map it cannot disappear until
2190 * after this open call completes. It is therefore safe to take a
2191 * new reference here without additional locking.
2194 kref_get(&reservations
->refs
);
2197 static void resv_map_put(struct vm_area_struct
*vma
)
2199 struct resv_map
*reservations
= vma_resv_map(vma
);
2203 kref_put(&reservations
->refs
, resv_map_release
);
2206 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2208 struct hstate
*h
= hstate_vma(vma
);
2209 struct resv_map
*reservations
= vma_resv_map(vma
);
2210 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2211 unsigned long reserve
;
2212 unsigned long start
;
2216 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2217 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2219 reserve
= (end
- start
) -
2220 region_count(&reservations
->regions
, start
, end
);
2225 hugetlb_acct_memory(h
, -reserve
);
2226 hugepage_subpool_put_pages(spool
, reserve
);
2232 * We cannot handle pagefaults against hugetlb pages at all. They cause
2233 * handle_mm_fault() to try to instantiate regular-sized pages in the
2234 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2237 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2243 const struct vm_operations_struct hugetlb_vm_ops
= {
2244 .fault
= hugetlb_vm_op_fault
,
2245 .open
= hugetlb_vm_op_open
,
2246 .close
= hugetlb_vm_op_close
,
2249 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2256 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2258 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2260 entry
= pte_mkyoung(entry
);
2261 entry
= pte_mkhuge(entry
);
2262 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2267 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2268 unsigned long address
, pte_t
*ptep
)
2272 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2273 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2274 update_mmu_cache(vma
, address
, ptep
);
2278 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2279 struct vm_area_struct
*vma
)
2281 pte_t
*src_pte
, *dst_pte
, entry
;
2282 struct page
*ptepage
;
2285 struct hstate
*h
= hstate_vma(vma
);
2286 unsigned long sz
= huge_page_size(h
);
2288 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2290 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2291 src_pte
= huge_pte_offset(src
, addr
);
2294 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2298 /* If the pagetables are shared don't copy or take references */
2299 if (dst_pte
== src_pte
)
2302 spin_lock(&dst
->page_table_lock
);
2303 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2304 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2306 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2307 entry
= huge_ptep_get(src_pte
);
2308 ptepage
= pte_page(entry
);
2310 page_dup_rmap(ptepage
);
2311 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2313 spin_unlock(&src
->page_table_lock
);
2314 spin_unlock(&dst
->page_table_lock
);
2322 static int is_hugetlb_entry_migration(pte_t pte
)
2326 if (huge_pte_none(pte
) || pte_present(pte
))
2328 swp
= pte_to_swp_entry(pte
);
2329 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2335 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2339 if (huge_pte_none(pte
) || pte_present(pte
))
2341 swp
= pte_to_swp_entry(pte
);
2342 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2348 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2349 unsigned long start
, unsigned long end
,
2350 struct page
*ref_page
)
2352 int force_flush
= 0;
2353 struct mm_struct
*mm
= vma
->vm_mm
;
2354 unsigned long address
;
2358 struct hstate
*h
= hstate_vma(vma
);
2359 unsigned long sz
= huge_page_size(h
);
2361 WARN_ON(!is_vm_hugetlb_page(vma
));
2362 BUG_ON(start
& ~huge_page_mask(h
));
2363 BUG_ON(end
& ~huge_page_mask(h
));
2365 tlb_start_vma(tlb
, vma
);
2366 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2368 spin_lock(&mm
->page_table_lock
);
2369 for (address
= start
; address
< end
; address
+= sz
) {
2370 ptep
= huge_pte_offset(mm
, address
);
2374 if (huge_pmd_unshare(mm
, &address
, ptep
))
2377 pte
= huge_ptep_get(ptep
);
2378 if (huge_pte_none(pte
))
2382 * HWPoisoned hugepage is already unmapped and dropped reference
2384 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
)))
2387 page
= pte_page(pte
);
2389 * If a reference page is supplied, it is because a specific
2390 * page is being unmapped, not a range. Ensure the page we
2391 * are about to unmap is the actual page of interest.
2394 if (page
!= ref_page
)
2398 * Mark the VMA as having unmapped its page so that
2399 * future faults in this VMA will fail rather than
2400 * looking like data was lost
2402 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2405 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2406 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2408 set_page_dirty(page
);
2410 page_remove_rmap(page
);
2411 force_flush
= !__tlb_remove_page(tlb
, page
);
2414 /* Bail out after unmapping reference page if supplied */
2418 spin_unlock(&mm
->page_table_lock
);
2420 * mmu_gather ran out of room to batch pages, we break out of
2421 * the PTE lock to avoid doing the potential expensive TLB invalidate
2422 * and page-free while holding it.
2427 if (address
< end
&& !ref_page
)
2430 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2431 tlb_end_vma(tlb
, vma
);
2434 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2435 unsigned long end
, struct page
*ref_page
)
2437 struct mm_struct
*mm
;
2438 struct mmu_gather tlb
;
2442 tlb_gather_mmu(&tlb
, mm
, 0);
2443 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2444 tlb_finish_mmu(&tlb
, start
, end
);
2448 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2449 * mappping it owns the reserve page for. The intention is to unmap the page
2450 * from other VMAs and let the children be SIGKILLed if they are faulting the
2453 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2454 struct page
*page
, unsigned long address
)
2456 struct hstate
*h
= hstate_vma(vma
);
2457 struct vm_area_struct
*iter_vma
;
2458 struct address_space
*mapping
;
2459 struct prio_tree_iter iter
;
2463 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2464 * from page cache lookup which is in HPAGE_SIZE units.
2466 address
= address
& huge_page_mask(h
);
2467 pgoff
= vma_hugecache_offset(h
, vma
, address
);
2468 mapping
= vma
->vm_file
->f_dentry
->d_inode
->i_mapping
;
2471 * Take the mapping lock for the duration of the table walk. As
2472 * this mapping should be shared between all the VMAs,
2473 * __unmap_hugepage_range() is called as the lock is already held
2475 mutex_lock(&mapping
->i_mmap_mutex
);
2476 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2477 /* Do not unmap the current VMA */
2478 if (iter_vma
== vma
)
2482 * Unmap the page from other VMAs without their own reserves.
2483 * They get marked to be SIGKILLed if they fault in these
2484 * areas. This is because a future no-page fault on this VMA
2485 * could insert a zeroed page instead of the data existing
2486 * from the time of fork. This would look like data corruption
2488 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2489 unmap_hugepage_range(iter_vma
, address
,
2490 address
+ huge_page_size(h
), page
);
2492 mutex_unlock(&mapping
->i_mmap_mutex
);
2498 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2499 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2500 * cannot race with other handlers or page migration.
2501 * Keep the pte_same checks anyway to make transition from the mutex easier.
2503 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2504 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2505 struct page
*pagecache_page
)
2507 struct hstate
*h
= hstate_vma(vma
);
2508 struct page
*old_page
, *new_page
;
2510 int outside_reserve
= 0;
2512 old_page
= pte_page(pte
);
2515 /* If no-one else is actually using this page, avoid the copy
2516 * and just make the page writable */
2517 avoidcopy
= (page_mapcount(old_page
) == 1);
2519 if (PageAnon(old_page
))
2520 page_move_anon_rmap(old_page
, vma
, address
);
2521 set_huge_ptep_writable(vma
, address
, ptep
);
2526 * If the process that created a MAP_PRIVATE mapping is about to
2527 * perform a COW due to a shared page count, attempt to satisfy
2528 * the allocation without using the existing reserves. The pagecache
2529 * page is used to determine if the reserve at this address was
2530 * consumed or not. If reserves were used, a partial faulted mapping
2531 * at the time of fork() could consume its reserves on COW instead
2532 * of the full address range.
2534 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2535 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2536 old_page
!= pagecache_page
)
2537 outside_reserve
= 1;
2539 page_cache_get(old_page
);
2541 /* Drop page_table_lock as buddy allocator may be called */
2542 spin_unlock(&mm
->page_table_lock
);
2543 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2545 if (IS_ERR(new_page
)) {
2546 long err
= PTR_ERR(new_page
);
2547 page_cache_release(old_page
);
2550 * If a process owning a MAP_PRIVATE mapping fails to COW,
2551 * it is due to references held by a child and an insufficient
2552 * huge page pool. To guarantee the original mappers
2553 * reliability, unmap the page from child processes. The child
2554 * may get SIGKILLed if it later faults.
2556 if (outside_reserve
) {
2557 BUG_ON(huge_pte_none(pte
));
2558 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2559 BUG_ON(huge_pte_none(pte
));
2560 spin_lock(&mm
->page_table_lock
);
2561 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2562 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2563 goto retry_avoidcopy
;
2565 * race occurs while re-acquiring page_table_lock, and
2573 /* Caller expects lock to be held */
2574 spin_lock(&mm
->page_table_lock
);
2576 return VM_FAULT_OOM
;
2578 return VM_FAULT_SIGBUS
;
2582 * When the original hugepage is shared one, it does not have
2583 * anon_vma prepared.
2585 if (unlikely(anon_vma_prepare(vma
))) {
2586 page_cache_release(new_page
);
2587 page_cache_release(old_page
);
2588 /* Caller expects lock to be held */
2589 spin_lock(&mm
->page_table_lock
);
2590 return VM_FAULT_OOM
;
2593 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2594 pages_per_huge_page(h
));
2595 __SetPageUptodate(new_page
);
2598 * Retake the page_table_lock to check for racing updates
2599 * before the page tables are altered
2601 spin_lock(&mm
->page_table_lock
);
2602 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2603 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2605 mmu_notifier_invalidate_range_start(mm
,
2606 address
& huge_page_mask(h
),
2607 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2608 huge_ptep_clear_flush(vma
, address
, ptep
);
2609 set_huge_pte_at(mm
, address
, ptep
,
2610 make_huge_pte(vma
, new_page
, 1));
2611 page_remove_rmap(old_page
);
2612 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2613 /* Make the old page be freed below */
2614 new_page
= old_page
;
2615 mmu_notifier_invalidate_range_end(mm
,
2616 address
& huge_page_mask(h
),
2617 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2619 page_cache_release(new_page
);
2620 page_cache_release(old_page
);
2624 /* Return the pagecache page at a given address within a VMA */
2625 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2626 struct vm_area_struct
*vma
, unsigned long address
)
2628 struct address_space
*mapping
;
2631 mapping
= vma
->vm_file
->f_mapping
;
2632 idx
= vma_hugecache_offset(h
, vma
, address
);
2634 return find_lock_page(mapping
, idx
);
2638 * Return whether there is a pagecache page to back given address within VMA.
2639 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2641 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2642 struct vm_area_struct
*vma
, unsigned long address
)
2644 struct address_space
*mapping
;
2648 mapping
= vma
->vm_file
->f_mapping
;
2649 idx
= vma_hugecache_offset(h
, vma
, address
);
2651 page
= find_get_page(mapping
, idx
);
2654 return page
!= NULL
;
2657 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2658 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2660 struct hstate
*h
= hstate_vma(vma
);
2661 int ret
= VM_FAULT_SIGBUS
;
2666 struct address_space
*mapping
;
2670 * Currently, we are forced to kill the process in the event the
2671 * original mapper has unmapped pages from the child due to a failed
2672 * COW. Warn that such a situation has occurred as it may not be obvious
2674 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2676 "PID %d killed due to inadequate hugepage pool\n",
2681 mapping
= vma
->vm_file
->f_mapping
;
2682 idx
= vma_hugecache_offset(h
, vma
, address
);
2685 * Use page lock to guard against racing truncation
2686 * before we get page_table_lock.
2689 page
= find_lock_page(mapping
, idx
);
2691 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2694 page
= alloc_huge_page(vma
, address
, 0);
2696 ret
= PTR_ERR(page
);
2700 ret
= VM_FAULT_SIGBUS
;
2703 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2704 __SetPageUptodate(page
);
2706 if (vma
->vm_flags
& VM_MAYSHARE
) {
2708 struct inode
*inode
= mapping
->host
;
2710 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2718 spin_lock(&inode
->i_lock
);
2719 inode
->i_blocks
+= blocks_per_huge_page(h
);
2720 spin_unlock(&inode
->i_lock
);
2723 if (unlikely(anon_vma_prepare(vma
))) {
2725 goto backout_unlocked
;
2731 * If memory error occurs between mmap() and fault, some process
2732 * don't have hwpoisoned swap entry for errored virtual address.
2733 * So we need to block hugepage fault by PG_hwpoison bit check.
2735 if (unlikely(PageHWPoison(page
))) {
2736 ret
= VM_FAULT_HWPOISON
|
2737 VM_FAULT_SET_HINDEX(hstate_index(h
));
2738 goto backout_unlocked
;
2743 * If we are going to COW a private mapping later, we examine the
2744 * pending reservations for this page now. This will ensure that
2745 * any allocations necessary to record that reservation occur outside
2748 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2749 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2751 goto backout_unlocked
;
2754 spin_lock(&mm
->page_table_lock
);
2755 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2760 if (!huge_pte_none(huge_ptep_get(ptep
)))
2764 hugepage_add_new_anon_rmap(page
, vma
, address
);
2766 page_dup_rmap(page
);
2767 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2768 && (vma
->vm_flags
& VM_SHARED
)));
2769 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2771 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2772 /* Optimization, do the COW without a second fault */
2773 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2776 spin_unlock(&mm
->page_table_lock
);
2782 spin_unlock(&mm
->page_table_lock
);
2789 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2790 unsigned long address
, unsigned int flags
)
2795 struct page
*page
= NULL
;
2796 struct page
*pagecache_page
= NULL
;
2797 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2798 struct hstate
*h
= hstate_vma(vma
);
2800 address
&= huge_page_mask(h
);
2802 ptep
= huge_pte_offset(mm
, address
);
2804 entry
= huge_ptep_get(ptep
);
2805 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2806 migration_entry_wait(mm
, (pmd_t
*)ptep
, address
);
2808 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2809 return VM_FAULT_HWPOISON_LARGE
|
2810 VM_FAULT_SET_HINDEX(hstate_index(h
));
2813 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2815 return VM_FAULT_OOM
;
2818 * Serialize hugepage allocation and instantiation, so that we don't
2819 * get spurious allocation failures if two CPUs race to instantiate
2820 * the same page in the page cache.
2822 mutex_lock(&hugetlb_instantiation_mutex
);
2823 entry
= huge_ptep_get(ptep
);
2824 if (huge_pte_none(entry
)) {
2825 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2832 * If we are going to COW the mapping later, we examine the pending
2833 * reservations for this page now. This will ensure that any
2834 * allocations necessary to record that reservation occur outside the
2835 * spinlock. For private mappings, we also lookup the pagecache
2836 * page now as it is used to determine if a reservation has been
2839 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2840 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2845 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2846 pagecache_page
= hugetlbfs_pagecache_page(h
,
2851 * hugetlb_cow() requires page locks of pte_page(entry) and
2852 * pagecache_page, so here we need take the former one
2853 * when page != pagecache_page or !pagecache_page.
2854 * Note that locking order is always pagecache_page -> page,
2855 * so no worry about deadlock.
2857 page
= pte_page(entry
);
2859 if (page
!= pagecache_page
)
2862 spin_lock(&mm
->page_table_lock
);
2863 /* Check for a racing update before calling hugetlb_cow */
2864 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2865 goto out_page_table_lock
;
2868 if (flags
& FAULT_FLAG_WRITE
) {
2869 if (!pte_write(entry
)) {
2870 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2872 goto out_page_table_lock
;
2874 entry
= pte_mkdirty(entry
);
2876 entry
= pte_mkyoung(entry
);
2877 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2878 flags
& FAULT_FLAG_WRITE
))
2879 update_mmu_cache(vma
, address
, ptep
);
2881 out_page_table_lock
:
2882 spin_unlock(&mm
->page_table_lock
);
2884 if (pagecache_page
) {
2885 unlock_page(pagecache_page
);
2886 put_page(pagecache_page
);
2888 if (page
!= pagecache_page
)
2893 mutex_unlock(&hugetlb_instantiation_mutex
);
2898 /* Can be overriden by architectures */
2899 __attribute__((weak
)) struct page
*
2900 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2901 pud_t
*pud
, int write
)
2907 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2908 struct page
**pages
, struct vm_area_struct
**vmas
,
2909 unsigned long *position
, int *length
, int i
,
2912 unsigned long pfn_offset
;
2913 unsigned long vaddr
= *position
;
2914 int remainder
= *length
;
2915 struct hstate
*h
= hstate_vma(vma
);
2917 spin_lock(&mm
->page_table_lock
);
2918 while (vaddr
< vma
->vm_end
&& remainder
) {
2924 * Some archs (sparc64, sh*) have multiple pte_ts to
2925 * each hugepage. We have to make sure we get the
2926 * first, for the page indexing below to work.
2928 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2929 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2932 * When coredumping, it suits get_dump_page if we just return
2933 * an error where there's an empty slot with no huge pagecache
2934 * to back it. This way, we avoid allocating a hugepage, and
2935 * the sparse dumpfile avoids allocating disk blocks, but its
2936 * huge holes still show up with zeroes where they need to be.
2938 if (absent
&& (flags
& FOLL_DUMP
) &&
2939 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2945 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2948 spin_unlock(&mm
->page_table_lock
);
2949 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2950 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2951 spin_lock(&mm
->page_table_lock
);
2952 if (!(ret
& VM_FAULT_ERROR
))
2959 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2960 page
= pte_page(huge_ptep_get(pte
));
2963 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2974 if (vaddr
< vma
->vm_end
&& remainder
&&
2975 pfn_offset
< pages_per_huge_page(h
)) {
2977 * We use pfn_offset to avoid touching the pageframes
2978 * of this compound page.
2983 spin_unlock(&mm
->page_table_lock
);
2984 *length
= remainder
;
2987 return i
? i
: -EFAULT
;
2990 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2991 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2993 struct mm_struct
*mm
= vma
->vm_mm
;
2994 unsigned long start
= address
;
2997 struct hstate
*h
= hstate_vma(vma
);
2999 BUG_ON(address
>= end
);
3000 flush_cache_range(vma
, address
, end
);
3002 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3003 spin_lock(&mm
->page_table_lock
);
3004 for (; address
< end
; address
+= huge_page_size(h
)) {
3005 ptep
= huge_pte_offset(mm
, address
);
3008 if (huge_pmd_unshare(mm
, &address
, ptep
))
3010 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3011 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3012 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
3013 set_huge_pte_at(mm
, address
, ptep
, pte
);
3016 spin_unlock(&mm
->page_table_lock
);
3017 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3019 flush_tlb_range(vma
, start
, end
);
3022 int hugetlb_reserve_pages(struct inode
*inode
,
3024 struct vm_area_struct
*vma
,
3025 vm_flags_t vm_flags
)
3028 struct hstate
*h
= hstate_inode(inode
);
3029 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3032 * Only apply hugepage reservation if asked. At fault time, an
3033 * attempt will be made for VM_NORESERVE to allocate a page
3034 * without using reserves
3036 if (vm_flags
& VM_NORESERVE
)
3040 * Shared mappings base their reservation on the number of pages that
3041 * are already allocated on behalf of the file. Private mappings need
3042 * to reserve the full area even if read-only as mprotect() may be
3043 * called to make the mapping read-write. Assume !vma is a shm mapping
3045 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3046 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3048 struct resv_map
*resv_map
= resv_map_alloc();
3054 set_vma_resv_map(vma
, resv_map
);
3055 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3063 /* There must be enough pages in the subpool for the mapping */
3064 if (hugepage_subpool_get_pages(spool
, chg
)) {
3070 * Check enough hugepages are available for the reservation.
3071 * Hand the pages back to the subpool if there are not
3073 ret
= hugetlb_acct_memory(h
, chg
);
3075 hugepage_subpool_put_pages(spool
, chg
);
3080 * Account for the reservations made. Shared mappings record regions
3081 * that have reservations as they are shared by multiple VMAs.
3082 * When the last VMA disappears, the region map says how much
3083 * the reservation was and the page cache tells how much of
3084 * the reservation was consumed. Private mappings are per-VMA and
3085 * only the consumed reservations are tracked. When the VMA
3086 * disappears, the original reservation is the VMA size and the
3087 * consumed reservations are stored in the map. Hence, nothing
3088 * else has to be done for private mappings here
3090 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3091 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3099 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3101 struct hstate
*h
= hstate_inode(inode
);
3102 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3103 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3105 spin_lock(&inode
->i_lock
);
3106 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3107 spin_unlock(&inode
->i_lock
);
3109 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3110 hugetlb_acct_memory(h
, -(chg
- freed
));
3113 #ifdef CONFIG_MEMORY_FAILURE
3115 /* Should be called in hugetlb_lock */
3116 static int is_hugepage_on_freelist(struct page
*hpage
)
3120 struct hstate
*h
= page_hstate(hpage
);
3121 int nid
= page_to_nid(hpage
);
3123 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3130 * This function is called from memory failure code.
3131 * Assume the caller holds page lock of the head page.
3133 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3135 struct hstate
*h
= page_hstate(hpage
);
3136 int nid
= page_to_nid(hpage
);
3139 spin_lock(&hugetlb_lock
);
3140 if (is_hugepage_on_freelist(hpage
)) {
3141 list_del(&hpage
->lru
);
3142 set_page_refcounted(hpage
);
3143 h
->free_huge_pages
--;
3144 h
->free_huge_pages_node
[nid
]--;
3147 spin_unlock(&hugetlb_lock
);