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>
35 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
36 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
37 unsigned long hugepages_treat_as_movable
;
39 int hugetlb_max_hstate __read_mostly
;
40 unsigned int default_hstate_idx
;
41 struct hstate hstates
[HUGE_MAX_HSTATE
];
43 __initdata
LIST_HEAD(huge_boot_pages
);
45 /* for command line parsing */
46 static struct hstate
* __initdata parsed_hstate
;
47 static unsigned long __initdata default_hstate_max_huge_pages
;
48 static unsigned long __initdata default_hstate_size
;
51 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
53 DEFINE_SPINLOCK(hugetlb_lock
);
55 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
57 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
59 spin_unlock(&spool
->lock
);
61 /* If no pages are used, and no other handles to the subpool
62 * remain, free the subpool the subpool remain */
67 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
69 struct hugepage_subpool
*spool
;
71 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
75 spin_lock_init(&spool
->lock
);
77 spool
->max_hpages
= nr_blocks
;
78 spool
->used_hpages
= 0;
83 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
85 spin_lock(&spool
->lock
);
86 BUG_ON(!spool
->count
);
88 unlock_or_release_subpool(spool
);
91 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
99 spin_lock(&spool
->lock
);
100 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
101 spool
->used_hpages
+= delta
;
105 spin_unlock(&spool
->lock
);
110 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
116 spin_lock(&spool
->lock
);
117 spool
->used_hpages
-= delta
;
118 /* If hugetlbfs_put_super couldn't free spool due to
119 * an outstanding quota reference, free it now. */
120 unlock_or_release_subpool(spool
);
123 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
125 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
128 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
130 return subpool_inode(vma
->vm_file
->f_dentry
->d_inode
);
134 * Region tracking -- allows tracking of reservations and instantiated pages
135 * across the pages in a mapping.
137 * The region data structures are protected by a combination of the mmap_sem
138 * and the hugetlb_instantion_mutex. To access or modify a region the caller
139 * must either hold the mmap_sem for write, or the mmap_sem for read and
140 * the hugetlb_instantiation mutex:
142 * down_write(&mm->mmap_sem);
144 * down_read(&mm->mmap_sem);
145 * mutex_lock(&hugetlb_instantiation_mutex);
148 struct list_head link
;
153 static long region_add(struct list_head
*head
, long f
, long t
)
155 struct file_region
*rg
, *nrg
, *trg
;
157 /* Locate the region we are either in or before. */
158 list_for_each_entry(rg
, head
, link
)
162 /* Round our left edge to the current segment if it encloses us. */
166 /* Check for and consume any regions we now overlap with. */
168 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
169 if (&rg
->link
== head
)
174 /* If this area reaches higher then extend our area to
175 * include it completely. If this is not the first area
176 * which we intend to reuse, free it. */
189 static long region_chg(struct list_head
*head
, long f
, long t
)
191 struct file_region
*rg
, *nrg
;
194 /* Locate the region we are before or in. */
195 list_for_each_entry(rg
, head
, link
)
199 /* If we are below the current region then a new region is required.
200 * Subtle, allocate a new region at the position but make it zero
201 * size such that we can guarantee to record the reservation. */
202 if (&rg
->link
== head
|| t
< rg
->from
) {
203 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
208 INIT_LIST_HEAD(&nrg
->link
);
209 list_add(&nrg
->link
, rg
->link
.prev
);
214 /* Round our left edge to the current segment if it encloses us. */
219 /* Check for and consume any regions we now overlap with. */
220 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
221 if (&rg
->link
== head
)
226 /* We overlap with this area, if it extends further than
227 * us then we must extend ourselves. Account for its
228 * existing reservation. */
233 chg
-= rg
->to
- rg
->from
;
238 static long region_truncate(struct list_head
*head
, long end
)
240 struct file_region
*rg
, *trg
;
243 /* Locate the region we are either in or before. */
244 list_for_each_entry(rg
, head
, link
)
247 if (&rg
->link
== head
)
250 /* If we are in the middle of a region then adjust it. */
251 if (end
> rg
->from
) {
254 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
257 /* Drop any remaining regions. */
258 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
259 if (&rg
->link
== head
)
261 chg
+= rg
->to
- rg
->from
;
268 static long region_count(struct list_head
*head
, long f
, long t
)
270 struct file_region
*rg
;
273 /* Locate each segment we overlap with, and count that overlap. */
274 list_for_each_entry(rg
, head
, link
) {
283 seg_from
= max(rg
->from
, f
);
284 seg_to
= min(rg
->to
, t
);
286 chg
+= seg_to
- seg_from
;
293 * Convert the address within this vma to the page offset within
294 * the mapping, in pagecache page units; huge pages here.
296 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
297 struct vm_area_struct
*vma
, unsigned long address
)
299 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
300 (vma
->vm_pgoff
>> huge_page_order(h
));
303 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
304 unsigned long address
)
306 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
310 * Return the size of the pages allocated when backing a VMA. In the majority
311 * cases this will be same size as used by the page table entries.
313 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
315 struct hstate
*hstate
;
317 if (!is_vm_hugetlb_page(vma
))
320 hstate
= hstate_vma(vma
);
322 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
324 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
327 * Return the page size being used by the MMU to back a VMA. In the majority
328 * of cases, the page size used by the kernel matches the MMU size. On
329 * architectures where it differs, an architecture-specific version of this
330 * function is required.
332 #ifndef vma_mmu_pagesize
333 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
335 return vma_kernel_pagesize(vma
);
340 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
341 * bits of the reservation map pointer, which are always clear due to
344 #define HPAGE_RESV_OWNER (1UL << 0)
345 #define HPAGE_RESV_UNMAPPED (1UL << 1)
346 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
349 * These helpers are used to track how many pages are reserved for
350 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
351 * is guaranteed to have their future faults succeed.
353 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
354 * the reserve counters are updated with the hugetlb_lock held. It is safe
355 * to reset the VMA at fork() time as it is not in use yet and there is no
356 * chance of the global counters getting corrupted as a result of the values.
358 * The private mapping reservation is represented in a subtly different
359 * manner to a shared mapping. A shared mapping has a region map associated
360 * with the underlying file, this region map represents the backing file
361 * pages which have ever had a reservation assigned which this persists even
362 * after the page is instantiated. A private mapping has a region map
363 * associated with the original mmap which is attached to all VMAs which
364 * reference it, this region map represents those offsets which have consumed
365 * reservation ie. where pages have been instantiated.
367 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
369 return (unsigned long)vma
->vm_private_data
;
372 static void set_vma_private_data(struct vm_area_struct
*vma
,
375 vma
->vm_private_data
= (void *)value
;
380 struct list_head regions
;
383 static struct resv_map
*resv_map_alloc(void)
385 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
389 kref_init(&resv_map
->refs
);
390 INIT_LIST_HEAD(&resv_map
->regions
);
395 static void resv_map_release(struct kref
*ref
)
397 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
399 /* Clear out any active regions before we release the map. */
400 region_truncate(&resv_map
->regions
, 0);
404 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
406 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
407 if (!(vma
->vm_flags
& VM_MAYSHARE
))
408 return (struct resv_map
*)(get_vma_private_data(vma
) &
413 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
415 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
416 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
418 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
419 HPAGE_RESV_MASK
) | (unsigned long)map
);
422 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
424 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
425 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
427 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
430 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
432 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
434 return (get_vma_private_data(vma
) & flag
) != 0;
437 /* Decrement the reserved pages in the hugepage pool by one */
438 static void decrement_hugepage_resv_vma(struct hstate
*h
,
439 struct vm_area_struct
*vma
)
441 if (vma
->vm_flags
& VM_NORESERVE
)
444 if (vma
->vm_flags
& VM_MAYSHARE
) {
445 /* Shared mappings always use reserves */
446 h
->resv_huge_pages
--;
447 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
449 * Only the process that called mmap() has reserves for
452 h
->resv_huge_pages
--;
456 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
457 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
459 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
460 if (!(vma
->vm_flags
& VM_MAYSHARE
))
461 vma
->vm_private_data
= (void *)0;
464 /* Returns true if the VMA has associated reserve pages */
465 static int vma_has_reserves(struct vm_area_struct
*vma
)
467 if (vma
->vm_flags
& VM_MAYSHARE
)
469 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
474 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
477 struct hstate
*h
= page_hstate(src
);
478 struct page
*dst_base
= dst
;
479 struct page
*src_base
= src
;
481 for (i
= 0; i
< pages_per_huge_page(h
); ) {
483 copy_highpage(dst
, src
);
486 dst
= mem_map_next(dst
, dst_base
, i
);
487 src
= mem_map_next(src
, src_base
, i
);
491 void copy_huge_page(struct page
*dst
, struct page
*src
)
494 struct hstate
*h
= page_hstate(src
);
496 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
497 copy_gigantic_page(dst
, src
);
502 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
504 copy_highpage(dst
+ i
, src
+ i
);
508 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
510 int nid
= page_to_nid(page
);
511 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
512 h
->free_huge_pages
++;
513 h
->free_huge_pages_node
[nid
]++;
516 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
520 if (list_empty(&h
->hugepage_freelists
[nid
]))
522 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
523 list_move(&page
->lru
, &h
->hugepage_activelist
);
524 set_page_refcounted(page
);
525 h
->free_huge_pages
--;
526 h
->free_huge_pages_node
[nid
]--;
530 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
531 struct vm_area_struct
*vma
,
532 unsigned long address
, int avoid_reserve
)
534 struct page
*page
= NULL
;
535 struct mempolicy
*mpol
;
536 nodemask_t
*nodemask
;
537 struct zonelist
*zonelist
;
540 unsigned int cpuset_mems_cookie
;
543 cpuset_mems_cookie
= get_mems_allowed();
544 zonelist
= huge_zonelist(vma
, address
,
545 htlb_alloc_mask
, &mpol
, &nodemask
);
547 * A child process with MAP_PRIVATE mappings created by their parent
548 * have no page reserves. This check ensures that reservations are
549 * not "stolen". The child may still get SIGKILLed
551 if (!vma_has_reserves(vma
) &&
552 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
555 /* If reserves cannot be used, ensure enough pages are in the pool */
556 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
559 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
560 MAX_NR_ZONES
- 1, nodemask
) {
561 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
562 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
565 decrement_hugepage_resv_vma(h
, vma
);
572 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
581 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
585 VM_BUG_ON(h
->order
>= MAX_ORDER
);
588 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
589 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
590 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
591 1 << PG_referenced
| 1 << PG_dirty
|
592 1 << PG_active
| 1 << PG_reserved
|
593 1 << PG_private
| 1 << PG_writeback
);
595 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
596 set_compound_page_dtor(page
, NULL
);
597 set_page_refcounted(page
);
598 arch_release_hugepage(page
);
599 __free_pages(page
, huge_page_order(h
));
602 struct hstate
*size_to_hstate(unsigned long size
)
607 if (huge_page_size(h
) == size
)
613 static void free_huge_page(struct page
*page
)
616 * Can't pass hstate in here because it is called from the
617 * compound page destructor.
619 struct hstate
*h
= page_hstate(page
);
620 int nid
= page_to_nid(page
);
621 struct hugepage_subpool
*spool
=
622 (struct hugepage_subpool
*)page_private(page
);
624 set_page_private(page
, 0);
625 page
->mapping
= NULL
;
626 BUG_ON(page_count(page
));
627 BUG_ON(page_mapcount(page
));
629 spin_lock(&hugetlb_lock
);
630 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
631 /* remove the page from active list */
632 list_del(&page
->lru
);
633 update_and_free_page(h
, page
);
634 h
->surplus_huge_pages
--;
635 h
->surplus_huge_pages_node
[nid
]--;
637 enqueue_huge_page(h
, page
);
639 spin_unlock(&hugetlb_lock
);
640 hugepage_subpool_put_pages(spool
, 1);
643 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
645 INIT_LIST_HEAD(&page
->lru
);
646 set_compound_page_dtor(page
, free_huge_page
);
647 spin_lock(&hugetlb_lock
);
648 set_hugetlb_cgroup(page
, NULL
);
650 h
->nr_huge_pages_node
[nid
]++;
651 spin_unlock(&hugetlb_lock
);
652 put_page(page
); /* free it into the hugepage allocator */
655 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
658 int nr_pages
= 1 << order
;
659 struct page
*p
= page
+ 1;
661 /* we rely on prep_new_huge_page to set the destructor */
662 set_compound_order(page
, order
);
664 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
666 set_page_count(p
, 0);
667 p
->first_page
= page
;
671 int PageHuge(struct page
*page
)
673 compound_page_dtor
*dtor
;
675 if (!PageCompound(page
))
678 page
= compound_head(page
);
679 dtor
= get_compound_page_dtor(page
);
681 return dtor
== free_huge_page
;
683 EXPORT_SYMBOL_GPL(PageHuge
);
685 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
689 if (h
->order
>= MAX_ORDER
)
692 page
= alloc_pages_exact_node(nid
,
693 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
694 __GFP_REPEAT
|__GFP_NOWARN
,
697 if (arch_prepare_hugepage(page
)) {
698 __free_pages(page
, huge_page_order(h
));
701 prep_new_huge_page(h
, page
, nid
);
708 * common helper functions for hstate_next_node_to_{alloc|free}.
709 * We may have allocated or freed a huge page based on a different
710 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
711 * be outside of *nodes_allowed. Ensure that we use an allowed
712 * node for alloc or free.
714 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
716 nid
= next_node(nid
, *nodes_allowed
);
717 if (nid
== MAX_NUMNODES
)
718 nid
= first_node(*nodes_allowed
);
719 VM_BUG_ON(nid
>= MAX_NUMNODES
);
724 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
726 if (!node_isset(nid
, *nodes_allowed
))
727 nid
= next_node_allowed(nid
, nodes_allowed
);
732 * returns the previously saved node ["this node"] from which to
733 * allocate a persistent huge page for the pool and advance the
734 * next node from which to allocate, handling wrap at end of node
737 static int hstate_next_node_to_alloc(struct hstate
*h
,
738 nodemask_t
*nodes_allowed
)
742 VM_BUG_ON(!nodes_allowed
);
744 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
745 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
750 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
757 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
758 next_nid
= start_nid
;
761 page
= alloc_fresh_huge_page_node(h
, next_nid
);
766 next_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
767 } while (next_nid
!= start_nid
);
770 count_vm_event(HTLB_BUDDY_PGALLOC
);
772 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
778 * helper for free_pool_huge_page() - return the previously saved
779 * node ["this node"] from which to free a huge page. Advance the
780 * next node id whether or not we find a free huge page to free so
781 * that the next attempt to free addresses the next node.
783 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
787 VM_BUG_ON(!nodes_allowed
);
789 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
790 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
796 * Free huge page from pool from next node to free.
797 * Attempt to keep persistent huge pages more or less
798 * balanced over allowed nodes.
799 * Called with hugetlb_lock locked.
801 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
808 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
809 next_nid
= start_nid
;
813 * If we're returning unused surplus pages, only examine
814 * nodes with surplus pages.
816 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
817 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
819 list_entry(h
->hugepage_freelists
[next_nid
].next
,
821 list_del(&page
->lru
);
822 h
->free_huge_pages
--;
823 h
->free_huge_pages_node
[next_nid
]--;
825 h
->surplus_huge_pages
--;
826 h
->surplus_huge_pages_node
[next_nid
]--;
828 update_and_free_page(h
, page
);
832 next_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
833 } while (next_nid
!= start_nid
);
838 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
843 if (h
->order
>= MAX_ORDER
)
847 * Assume we will successfully allocate the surplus page to
848 * prevent racing processes from causing the surplus to exceed
851 * This however introduces a different race, where a process B
852 * tries to grow the static hugepage pool while alloc_pages() is
853 * called by process A. B will only examine the per-node
854 * counters in determining if surplus huge pages can be
855 * converted to normal huge pages in adjust_pool_surplus(). A
856 * won't be able to increment the per-node counter, until the
857 * lock is dropped by B, but B doesn't drop hugetlb_lock until
858 * no more huge pages can be converted from surplus to normal
859 * state (and doesn't try to convert again). Thus, we have a
860 * case where a surplus huge page exists, the pool is grown, and
861 * the surplus huge page still exists after, even though it
862 * should just have been converted to a normal huge page. This
863 * does not leak memory, though, as the hugepage will be freed
864 * once it is out of use. It also does not allow the counters to
865 * go out of whack in adjust_pool_surplus() as we don't modify
866 * the node values until we've gotten the hugepage and only the
867 * per-node value is checked there.
869 spin_lock(&hugetlb_lock
);
870 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
871 spin_unlock(&hugetlb_lock
);
875 h
->surplus_huge_pages
++;
877 spin_unlock(&hugetlb_lock
);
879 if (nid
== NUMA_NO_NODE
)
880 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
881 __GFP_REPEAT
|__GFP_NOWARN
,
884 page
= alloc_pages_exact_node(nid
,
885 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
886 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
888 if (page
&& arch_prepare_hugepage(page
)) {
889 __free_pages(page
, huge_page_order(h
));
893 spin_lock(&hugetlb_lock
);
895 INIT_LIST_HEAD(&page
->lru
);
896 r_nid
= page_to_nid(page
);
897 set_compound_page_dtor(page
, free_huge_page
);
898 set_hugetlb_cgroup(page
, NULL
);
900 * We incremented the global counters already
902 h
->nr_huge_pages_node
[r_nid
]++;
903 h
->surplus_huge_pages_node
[r_nid
]++;
904 __count_vm_event(HTLB_BUDDY_PGALLOC
);
907 h
->surplus_huge_pages
--;
908 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
910 spin_unlock(&hugetlb_lock
);
916 * This allocation function is useful in the context where vma is irrelevant.
917 * E.g. soft-offlining uses this function because it only cares physical
918 * address of error page.
920 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
924 spin_lock(&hugetlb_lock
);
925 page
= dequeue_huge_page_node(h
, nid
);
926 spin_unlock(&hugetlb_lock
);
929 page
= alloc_buddy_huge_page(h
, nid
);
935 * Increase the hugetlb pool such that it can accommodate a reservation
938 static int gather_surplus_pages(struct hstate
*h
, int delta
)
940 struct list_head surplus_list
;
941 struct page
*page
, *tmp
;
943 int needed
, allocated
;
944 bool alloc_ok
= true;
946 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
948 h
->resv_huge_pages
+= delta
;
953 INIT_LIST_HEAD(&surplus_list
);
957 spin_unlock(&hugetlb_lock
);
958 for (i
= 0; i
< needed
; i
++) {
959 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
964 list_add(&page
->lru
, &surplus_list
);
969 * After retaking hugetlb_lock, we need to recalculate 'needed'
970 * because either resv_huge_pages or free_huge_pages may have changed.
972 spin_lock(&hugetlb_lock
);
973 needed
= (h
->resv_huge_pages
+ delta
) -
974 (h
->free_huge_pages
+ allocated
);
979 * We were not able to allocate enough pages to
980 * satisfy the entire reservation so we free what
981 * we've allocated so far.
986 * The surplus_list now contains _at_least_ the number of extra pages
987 * needed to accommodate the reservation. Add the appropriate number
988 * of pages to the hugetlb pool and free the extras back to the buddy
989 * allocator. Commit the entire reservation here to prevent another
990 * process from stealing the pages as they are added to the pool but
991 * before they are reserved.
994 h
->resv_huge_pages
+= delta
;
997 /* Free the needed pages to the hugetlb pool */
998 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1002 * This page is now managed by the hugetlb allocator and has
1003 * no users -- drop the buddy allocator's reference.
1005 put_page_testzero(page
);
1006 VM_BUG_ON(page_count(page
));
1007 enqueue_huge_page(h
, page
);
1010 spin_unlock(&hugetlb_lock
);
1012 /* Free unnecessary surplus pages to the buddy allocator */
1013 if (!list_empty(&surplus_list
)) {
1014 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1018 spin_lock(&hugetlb_lock
);
1024 * When releasing a hugetlb pool reservation, any surplus pages that were
1025 * allocated to satisfy the reservation must be explicitly freed if they were
1027 * Called with hugetlb_lock held.
1029 static void return_unused_surplus_pages(struct hstate
*h
,
1030 unsigned long unused_resv_pages
)
1032 unsigned long nr_pages
;
1034 /* Uncommit the reservation */
1035 h
->resv_huge_pages
-= unused_resv_pages
;
1037 /* Cannot return gigantic pages currently */
1038 if (h
->order
>= MAX_ORDER
)
1041 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1044 * We want to release as many surplus pages as possible, spread
1045 * evenly across all nodes with memory. Iterate across these nodes
1046 * until we can no longer free unreserved surplus pages. This occurs
1047 * when the nodes with surplus pages have no free pages.
1048 * free_pool_huge_page() will balance the the freed pages across the
1049 * on-line nodes with memory and will handle the hstate accounting.
1051 while (nr_pages
--) {
1052 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
1058 * Determine if the huge page at addr within the vma has an associated
1059 * reservation. Where it does not we will need to logically increase
1060 * reservation and actually increase subpool usage before an allocation
1061 * can occur. Where any new reservation would be required the
1062 * reservation change is prepared, but not committed. Once the page
1063 * has been allocated from the subpool and instantiated the change should
1064 * be committed via vma_commit_reservation. No action is required on
1067 static long vma_needs_reservation(struct hstate
*h
,
1068 struct vm_area_struct
*vma
, unsigned long addr
)
1070 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1071 struct inode
*inode
= mapping
->host
;
1073 if (vma
->vm_flags
& VM_MAYSHARE
) {
1074 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1075 return region_chg(&inode
->i_mapping
->private_list
,
1078 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1083 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1084 struct resv_map
*reservations
= vma_resv_map(vma
);
1086 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1092 static void vma_commit_reservation(struct hstate
*h
,
1093 struct vm_area_struct
*vma
, unsigned long addr
)
1095 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1096 struct inode
*inode
= mapping
->host
;
1098 if (vma
->vm_flags
& VM_MAYSHARE
) {
1099 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1100 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1102 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1103 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1104 struct resv_map
*reservations
= vma_resv_map(vma
);
1106 /* Mark this page used in the map. */
1107 region_add(&reservations
->regions
, idx
, idx
+ 1);
1111 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1112 unsigned long addr
, int avoid_reserve
)
1114 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1115 struct hstate
*h
= hstate_vma(vma
);
1120 * Processes that did not create the mapping will have no
1121 * reserves and will not have accounted against subpool
1122 * limit. Check that the subpool limit can be made before
1123 * satisfying the allocation MAP_NORESERVE mappings may also
1124 * need pages and subpool limit allocated allocated if no reserve
1127 chg
= vma_needs_reservation(h
, vma
, addr
);
1129 return ERR_PTR(-ENOMEM
);
1131 if (hugepage_subpool_get_pages(spool
, chg
))
1132 return ERR_PTR(-ENOSPC
);
1134 spin_lock(&hugetlb_lock
);
1135 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1136 spin_unlock(&hugetlb_lock
);
1139 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1141 hugepage_subpool_put_pages(spool
, chg
);
1142 return ERR_PTR(-ENOSPC
);
1146 set_page_private(page
, (unsigned long)spool
);
1148 vma_commit_reservation(h
, vma
, addr
);
1153 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1155 struct huge_bootmem_page
*m
;
1156 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1161 addr
= __alloc_bootmem_node_nopanic(
1162 NODE_DATA(hstate_next_node_to_alloc(h
,
1163 &node_states
[N_HIGH_MEMORY
])),
1164 huge_page_size(h
), huge_page_size(h
), 0);
1168 * Use the beginning of the huge page to store the
1169 * huge_bootmem_page struct (until gather_bootmem
1170 * puts them into the mem_map).
1180 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1181 /* Put them into a private list first because mem_map is not up yet */
1182 list_add(&m
->list
, &huge_boot_pages
);
1187 static void prep_compound_huge_page(struct page
*page
, int order
)
1189 if (unlikely(order
> (MAX_ORDER
- 1)))
1190 prep_compound_gigantic_page(page
, order
);
1192 prep_compound_page(page
, order
);
1195 /* Put bootmem huge pages into the standard lists after mem_map is up */
1196 static void __init
gather_bootmem_prealloc(void)
1198 struct huge_bootmem_page
*m
;
1200 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1201 struct hstate
*h
= m
->hstate
;
1204 #ifdef CONFIG_HIGHMEM
1205 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1206 free_bootmem_late((unsigned long)m
,
1207 sizeof(struct huge_bootmem_page
));
1209 page
= virt_to_page(m
);
1211 __ClearPageReserved(page
);
1212 WARN_ON(page_count(page
) != 1);
1213 prep_compound_huge_page(page
, h
->order
);
1214 prep_new_huge_page(h
, page
, page_to_nid(page
));
1216 * If we had gigantic hugepages allocated at boot time, we need
1217 * to restore the 'stolen' pages to totalram_pages in order to
1218 * fix confusing memory reports from free(1) and another
1219 * side-effects, like CommitLimit going negative.
1221 if (h
->order
> (MAX_ORDER
- 1))
1222 totalram_pages
+= 1 << h
->order
;
1226 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1230 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1231 if (h
->order
>= MAX_ORDER
) {
1232 if (!alloc_bootmem_huge_page(h
))
1234 } else if (!alloc_fresh_huge_page(h
,
1235 &node_states
[N_HIGH_MEMORY
]))
1238 h
->max_huge_pages
= i
;
1241 static void __init
hugetlb_init_hstates(void)
1245 for_each_hstate(h
) {
1246 /* oversize hugepages were init'ed in early boot */
1247 if (h
->order
< MAX_ORDER
)
1248 hugetlb_hstate_alloc_pages(h
);
1252 static char * __init
memfmt(char *buf
, unsigned long n
)
1254 if (n
>= (1UL << 30))
1255 sprintf(buf
, "%lu GB", n
>> 30);
1256 else if (n
>= (1UL << 20))
1257 sprintf(buf
, "%lu MB", n
>> 20);
1259 sprintf(buf
, "%lu KB", n
>> 10);
1263 static void __init
report_hugepages(void)
1267 for_each_hstate(h
) {
1269 printk(KERN_INFO
"HugeTLB registered %s page size, "
1270 "pre-allocated %ld pages\n",
1271 memfmt(buf
, huge_page_size(h
)),
1272 h
->free_huge_pages
);
1276 #ifdef CONFIG_HIGHMEM
1277 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1278 nodemask_t
*nodes_allowed
)
1282 if (h
->order
>= MAX_ORDER
)
1285 for_each_node_mask(i
, *nodes_allowed
) {
1286 struct page
*page
, *next
;
1287 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1288 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1289 if (count
>= h
->nr_huge_pages
)
1291 if (PageHighMem(page
))
1293 list_del(&page
->lru
);
1294 update_and_free_page(h
, page
);
1295 h
->free_huge_pages
--;
1296 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1301 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1302 nodemask_t
*nodes_allowed
)
1308 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1309 * balanced by operating on them in a round-robin fashion.
1310 * Returns 1 if an adjustment was made.
1312 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1315 int start_nid
, next_nid
;
1318 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1321 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1323 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1324 next_nid
= start_nid
;
1330 * To shrink on this node, there must be a surplus page
1332 if (!h
->surplus_huge_pages_node
[nid
]) {
1333 next_nid
= hstate_next_node_to_alloc(h
,
1340 * Surplus cannot exceed the total number of pages
1342 if (h
->surplus_huge_pages_node
[nid
] >=
1343 h
->nr_huge_pages_node
[nid
]) {
1344 next_nid
= hstate_next_node_to_free(h
,
1350 h
->surplus_huge_pages
+= delta
;
1351 h
->surplus_huge_pages_node
[nid
] += delta
;
1354 } while (next_nid
!= start_nid
);
1359 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1360 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1361 nodemask_t
*nodes_allowed
)
1363 unsigned long min_count
, ret
;
1365 if (h
->order
>= MAX_ORDER
)
1366 return h
->max_huge_pages
;
1369 * Increase the pool size
1370 * First take pages out of surplus state. Then make up the
1371 * remaining difference by allocating fresh huge pages.
1373 * We might race with alloc_buddy_huge_page() here and be unable
1374 * to convert a surplus huge page to a normal huge page. That is
1375 * not critical, though, it just means the overall size of the
1376 * pool might be one hugepage larger than it needs to be, but
1377 * within all the constraints specified by the sysctls.
1379 spin_lock(&hugetlb_lock
);
1380 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1381 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1385 while (count
> persistent_huge_pages(h
)) {
1387 * If this allocation races such that we no longer need the
1388 * page, free_huge_page will handle it by freeing the page
1389 * and reducing the surplus.
1391 spin_unlock(&hugetlb_lock
);
1392 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1393 spin_lock(&hugetlb_lock
);
1397 /* Bail for signals. Probably ctrl-c from user */
1398 if (signal_pending(current
))
1403 * Decrease the pool size
1404 * First return free pages to the buddy allocator (being careful
1405 * to keep enough around to satisfy reservations). Then place
1406 * pages into surplus state as needed so the pool will shrink
1407 * to the desired size as pages become free.
1409 * By placing pages into the surplus state independent of the
1410 * overcommit value, we are allowing the surplus pool size to
1411 * exceed overcommit. There are few sane options here. Since
1412 * alloc_buddy_huge_page() is checking the global counter,
1413 * though, we'll note that we're not allowed to exceed surplus
1414 * and won't grow the pool anywhere else. Not until one of the
1415 * sysctls are changed, or the surplus pages go out of use.
1417 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1418 min_count
= max(count
, min_count
);
1419 try_to_free_low(h
, min_count
, nodes_allowed
);
1420 while (min_count
< persistent_huge_pages(h
)) {
1421 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1424 while (count
< persistent_huge_pages(h
)) {
1425 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1429 ret
= persistent_huge_pages(h
);
1430 spin_unlock(&hugetlb_lock
);
1434 #define HSTATE_ATTR_RO(_name) \
1435 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1437 #define HSTATE_ATTR(_name) \
1438 static struct kobj_attribute _name##_attr = \
1439 __ATTR(_name, 0644, _name##_show, _name##_store)
1441 static struct kobject
*hugepages_kobj
;
1442 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1444 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1446 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1450 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1451 if (hstate_kobjs
[i
] == kobj
) {
1453 *nidp
= NUMA_NO_NODE
;
1457 return kobj_to_node_hstate(kobj
, nidp
);
1460 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1461 struct kobj_attribute
*attr
, char *buf
)
1464 unsigned long nr_huge_pages
;
1467 h
= kobj_to_hstate(kobj
, &nid
);
1468 if (nid
== NUMA_NO_NODE
)
1469 nr_huge_pages
= h
->nr_huge_pages
;
1471 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1473 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1476 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1477 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1478 const char *buf
, size_t len
)
1482 unsigned long count
;
1484 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1486 err
= strict_strtoul(buf
, 10, &count
);
1490 h
= kobj_to_hstate(kobj
, &nid
);
1491 if (h
->order
>= MAX_ORDER
) {
1496 if (nid
== NUMA_NO_NODE
) {
1498 * global hstate attribute
1500 if (!(obey_mempolicy
&&
1501 init_nodemask_of_mempolicy(nodes_allowed
))) {
1502 NODEMASK_FREE(nodes_allowed
);
1503 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1505 } else if (nodes_allowed
) {
1507 * per node hstate attribute: adjust count to global,
1508 * but restrict alloc/free to the specified node.
1510 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1511 init_nodemask_of_node(nodes_allowed
, nid
);
1513 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1515 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1517 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1518 NODEMASK_FREE(nodes_allowed
);
1522 NODEMASK_FREE(nodes_allowed
);
1526 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1527 struct kobj_attribute
*attr
, char *buf
)
1529 return nr_hugepages_show_common(kobj
, attr
, buf
);
1532 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1533 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1535 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1537 HSTATE_ATTR(nr_hugepages
);
1542 * hstate attribute for optionally mempolicy-based constraint on persistent
1543 * huge page alloc/free.
1545 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1546 struct kobj_attribute
*attr
, char *buf
)
1548 return nr_hugepages_show_common(kobj
, attr
, buf
);
1551 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1552 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1554 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1556 HSTATE_ATTR(nr_hugepages_mempolicy
);
1560 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1561 struct kobj_attribute
*attr
, char *buf
)
1563 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1564 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1567 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1568 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1571 unsigned long input
;
1572 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1574 if (h
->order
>= MAX_ORDER
)
1577 err
= strict_strtoul(buf
, 10, &input
);
1581 spin_lock(&hugetlb_lock
);
1582 h
->nr_overcommit_huge_pages
= input
;
1583 spin_unlock(&hugetlb_lock
);
1587 HSTATE_ATTR(nr_overcommit_hugepages
);
1589 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1590 struct kobj_attribute
*attr
, char *buf
)
1593 unsigned long free_huge_pages
;
1596 h
= kobj_to_hstate(kobj
, &nid
);
1597 if (nid
== NUMA_NO_NODE
)
1598 free_huge_pages
= h
->free_huge_pages
;
1600 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1602 return sprintf(buf
, "%lu\n", free_huge_pages
);
1604 HSTATE_ATTR_RO(free_hugepages
);
1606 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1607 struct kobj_attribute
*attr
, char *buf
)
1609 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1610 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1612 HSTATE_ATTR_RO(resv_hugepages
);
1614 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1615 struct kobj_attribute
*attr
, char *buf
)
1618 unsigned long surplus_huge_pages
;
1621 h
= kobj_to_hstate(kobj
, &nid
);
1622 if (nid
== NUMA_NO_NODE
)
1623 surplus_huge_pages
= h
->surplus_huge_pages
;
1625 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1627 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1629 HSTATE_ATTR_RO(surplus_hugepages
);
1631 static struct attribute
*hstate_attrs
[] = {
1632 &nr_hugepages_attr
.attr
,
1633 &nr_overcommit_hugepages_attr
.attr
,
1634 &free_hugepages_attr
.attr
,
1635 &resv_hugepages_attr
.attr
,
1636 &surplus_hugepages_attr
.attr
,
1638 &nr_hugepages_mempolicy_attr
.attr
,
1643 static struct attribute_group hstate_attr_group
= {
1644 .attrs
= hstate_attrs
,
1647 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1648 struct kobject
**hstate_kobjs
,
1649 struct attribute_group
*hstate_attr_group
)
1652 int hi
= hstate_index(h
);
1654 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1655 if (!hstate_kobjs
[hi
])
1658 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1660 kobject_put(hstate_kobjs
[hi
]);
1665 static void __init
hugetlb_sysfs_init(void)
1670 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1671 if (!hugepages_kobj
)
1674 for_each_hstate(h
) {
1675 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1676 hstate_kobjs
, &hstate_attr_group
);
1678 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1686 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1687 * with node devices in node_devices[] using a parallel array. The array
1688 * index of a node device or _hstate == node id.
1689 * This is here to avoid any static dependency of the node device driver, in
1690 * the base kernel, on the hugetlb module.
1692 struct node_hstate
{
1693 struct kobject
*hugepages_kobj
;
1694 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1696 struct node_hstate node_hstates
[MAX_NUMNODES
];
1699 * A subset of global hstate attributes for node devices
1701 static struct attribute
*per_node_hstate_attrs
[] = {
1702 &nr_hugepages_attr
.attr
,
1703 &free_hugepages_attr
.attr
,
1704 &surplus_hugepages_attr
.attr
,
1708 static struct attribute_group per_node_hstate_attr_group
= {
1709 .attrs
= per_node_hstate_attrs
,
1713 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1714 * Returns node id via non-NULL nidp.
1716 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1720 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1721 struct node_hstate
*nhs
= &node_hstates
[nid
];
1723 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1724 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1736 * Unregister hstate attributes from a single node device.
1737 * No-op if no hstate attributes attached.
1739 void hugetlb_unregister_node(struct node
*node
)
1742 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1744 if (!nhs
->hugepages_kobj
)
1745 return; /* no hstate attributes */
1747 for_each_hstate(h
) {
1748 int idx
= hstate_index(h
);
1749 if (nhs
->hstate_kobjs
[idx
]) {
1750 kobject_put(nhs
->hstate_kobjs
[idx
]);
1751 nhs
->hstate_kobjs
[idx
] = NULL
;
1755 kobject_put(nhs
->hugepages_kobj
);
1756 nhs
->hugepages_kobj
= NULL
;
1760 * hugetlb module exit: unregister hstate attributes from node devices
1763 static void hugetlb_unregister_all_nodes(void)
1768 * disable node device registrations.
1770 register_hugetlbfs_with_node(NULL
, NULL
);
1773 * remove hstate attributes from any nodes that have them.
1775 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1776 hugetlb_unregister_node(&node_devices
[nid
]);
1780 * Register hstate attributes for a single node device.
1781 * No-op if attributes already registered.
1783 void hugetlb_register_node(struct node
*node
)
1786 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1789 if (nhs
->hugepages_kobj
)
1790 return; /* already allocated */
1792 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1794 if (!nhs
->hugepages_kobj
)
1797 for_each_hstate(h
) {
1798 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1800 &per_node_hstate_attr_group
);
1802 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1804 h
->name
, node
->dev
.id
);
1805 hugetlb_unregister_node(node
);
1812 * hugetlb init time: register hstate attributes for all registered node
1813 * devices of nodes that have memory. All on-line nodes should have
1814 * registered their associated device by this time.
1816 static void hugetlb_register_all_nodes(void)
1820 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1821 struct node
*node
= &node_devices
[nid
];
1822 if (node
->dev
.id
== nid
)
1823 hugetlb_register_node(node
);
1827 * Let the node device driver know we're here so it can
1828 * [un]register hstate attributes on node hotplug.
1830 register_hugetlbfs_with_node(hugetlb_register_node
,
1831 hugetlb_unregister_node
);
1833 #else /* !CONFIG_NUMA */
1835 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1843 static void hugetlb_unregister_all_nodes(void) { }
1845 static void hugetlb_register_all_nodes(void) { }
1849 static void __exit
hugetlb_exit(void)
1853 hugetlb_unregister_all_nodes();
1855 for_each_hstate(h
) {
1856 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1859 kobject_put(hugepages_kobj
);
1861 module_exit(hugetlb_exit
);
1863 static int __init
hugetlb_init(void)
1865 /* Some platform decide whether they support huge pages at boot
1866 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1867 * there is no such support
1869 if (HPAGE_SHIFT
== 0)
1872 if (!size_to_hstate(default_hstate_size
)) {
1873 default_hstate_size
= HPAGE_SIZE
;
1874 if (!size_to_hstate(default_hstate_size
))
1875 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1877 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1878 if (default_hstate_max_huge_pages
)
1879 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1881 hugetlb_init_hstates();
1883 gather_bootmem_prealloc();
1887 hugetlb_sysfs_init();
1889 hugetlb_register_all_nodes();
1893 module_init(hugetlb_init
);
1895 /* Should be called on processing a hugepagesz=... option */
1896 void __init
hugetlb_add_hstate(unsigned order
)
1901 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1902 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1905 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1907 h
= &hstates
[hugetlb_max_hstate
++];
1909 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1910 h
->nr_huge_pages
= 0;
1911 h
->free_huge_pages
= 0;
1912 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1913 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1914 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1915 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1916 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1917 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1918 huge_page_size(h
)/1024);
1923 static int __init
hugetlb_nrpages_setup(char *s
)
1926 static unsigned long *last_mhp
;
1929 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1930 * so this hugepages= parameter goes to the "default hstate".
1932 if (!hugetlb_max_hstate
)
1933 mhp
= &default_hstate_max_huge_pages
;
1935 mhp
= &parsed_hstate
->max_huge_pages
;
1937 if (mhp
== last_mhp
) {
1938 printk(KERN_WARNING
"hugepages= specified twice without "
1939 "interleaving hugepagesz=, ignoring\n");
1943 if (sscanf(s
, "%lu", mhp
) <= 0)
1947 * Global state is always initialized later in hugetlb_init.
1948 * But we need to allocate >= MAX_ORDER hstates here early to still
1949 * use the bootmem allocator.
1951 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1952 hugetlb_hstate_alloc_pages(parsed_hstate
);
1958 __setup("hugepages=", hugetlb_nrpages_setup
);
1960 static int __init
hugetlb_default_setup(char *s
)
1962 default_hstate_size
= memparse(s
, &s
);
1965 __setup("default_hugepagesz=", hugetlb_default_setup
);
1967 static unsigned int cpuset_mems_nr(unsigned int *array
)
1970 unsigned int nr
= 0;
1972 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1978 #ifdef CONFIG_SYSCTL
1979 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1980 struct ctl_table
*table
, int write
,
1981 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1983 struct hstate
*h
= &default_hstate
;
1987 tmp
= h
->max_huge_pages
;
1989 if (write
&& h
->order
>= MAX_ORDER
)
1993 table
->maxlen
= sizeof(unsigned long);
1994 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1999 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2000 GFP_KERNEL
| __GFP_NORETRY
);
2001 if (!(obey_mempolicy
&&
2002 init_nodemask_of_mempolicy(nodes_allowed
))) {
2003 NODEMASK_FREE(nodes_allowed
);
2004 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
2006 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2008 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
2009 NODEMASK_FREE(nodes_allowed
);
2015 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2016 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2019 return hugetlb_sysctl_handler_common(false, table
, write
,
2020 buffer
, length
, ppos
);
2024 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2025 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2027 return hugetlb_sysctl_handler_common(true, table
, write
,
2028 buffer
, length
, ppos
);
2030 #endif /* CONFIG_NUMA */
2032 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2033 void __user
*buffer
,
2034 size_t *length
, loff_t
*ppos
)
2036 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2037 if (hugepages_treat_as_movable
)
2038 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2040 htlb_alloc_mask
= GFP_HIGHUSER
;
2044 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2045 void __user
*buffer
,
2046 size_t *length
, loff_t
*ppos
)
2048 struct hstate
*h
= &default_hstate
;
2052 tmp
= h
->nr_overcommit_huge_pages
;
2054 if (write
&& h
->order
>= MAX_ORDER
)
2058 table
->maxlen
= sizeof(unsigned long);
2059 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2064 spin_lock(&hugetlb_lock
);
2065 h
->nr_overcommit_huge_pages
= tmp
;
2066 spin_unlock(&hugetlb_lock
);
2072 #endif /* CONFIG_SYSCTL */
2074 void hugetlb_report_meminfo(struct seq_file
*m
)
2076 struct hstate
*h
= &default_hstate
;
2078 "HugePages_Total: %5lu\n"
2079 "HugePages_Free: %5lu\n"
2080 "HugePages_Rsvd: %5lu\n"
2081 "HugePages_Surp: %5lu\n"
2082 "Hugepagesize: %8lu kB\n",
2086 h
->surplus_huge_pages
,
2087 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2090 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2092 struct hstate
*h
= &default_hstate
;
2094 "Node %d HugePages_Total: %5u\n"
2095 "Node %d HugePages_Free: %5u\n"
2096 "Node %d HugePages_Surp: %5u\n",
2097 nid
, h
->nr_huge_pages_node
[nid
],
2098 nid
, h
->free_huge_pages_node
[nid
],
2099 nid
, h
->surplus_huge_pages_node
[nid
]);
2102 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2103 unsigned long hugetlb_total_pages(void)
2105 struct hstate
*h
= &default_hstate
;
2106 return h
->nr_huge_pages
* pages_per_huge_page(h
);
2109 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2113 spin_lock(&hugetlb_lock
);
2115 * When cpuset is configured, it breaks the strict hugetlb page
2116 * reservation as the accounting is done on a global variable. Such
2117 * reservation is completely rubbish in the presence of cpuset because
2118 * the reservation is not checked against page availability for the
2119 * current cpuset. Application can still potentially OOM'ed by kernel
2120 * with lack of free htlb page in cpuset that the task is in.
2121 * Attempt to enforce strict accounting with cpuset is almost
2122 * impossible (or too ugly) because cpuset is too fluid that
2123 * task or memory node can be dynamically moved between cpusets.
2125 * The change of semantics for shared hugetlb mapping with cpuset is
2126 * undesirable. However, in order to preserve some of the semantics,
2127 * we fall back to check against current free page availability as
2128 * a best attempt and hopefully to minimize the impact of changing
2129 * semantics that cpuset has.
2132 if (gather_surplus_pages(h
, delta
) < 0)
2135 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2136 return_unused_surplus_pages(h
, delta
);
2143 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2146 spin_unlock(&hugetlb_lock
);
2150 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2152 struct resv_map
*reservations
= vma_resv_map(vma
);
2155 * This new VMA should share its siblings reservation map if present.
2156 * The VMA will only ever have a valid reservation map pointer where
2157 * it is being copied for another still existing VMA. As that VMA
2158 * has a reference to the reservation map it cannot disappear until
2159 * after this open call completes. It is therefore safe to take a
2160 * new reference here without additional locking.
2163 kref_get(&reservations
->refs
);
2166 static void resv_map_put(struct vm_area_struct
*vma
)
2168 struct resv_map
*reservations
= vma_resv_map(vma
);
2172 kref_put(&reservations
->refs
, resv_map_release
);
2175 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2177 struct hstate
*h
= hstate_vma(vma
);
2178 struct resv_map
*reservations
= vma_resv_map(vma
);
2179 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2180 unsigned long reserve
;
2181 unsigned long start
;
2185 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2186 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2188 reserve
= (end
- start
) -
2189 region_count(&reservations
->regions
, start
, end
);
2194 hugetlb_acct_memory(h
, -reserve
);
2195 hugepage_subpool_put_pages(spool
, reserve
);
2201 * We cannot handle pagefaults against hugetlb pages at all. They cause
2202 * handle_mm_fault() to try to instantiate regular-sized pages in the
2203 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2206 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2212 const struct vm_operations_struct hugetlb_vm_ops
= {
2213 .fault
= hugetlb_vm_op_fault
,
2214 .open
= hugetlb_vm_op_open
,
2215 .close
= hugetlb_vm_op_close
,
2218 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2225 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2227 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2229 entry
= pte_mkyoung(entry
);
2230 entry
= pte_mkhuge(entry
);
2231 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2236 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2237 unsigned long address
, pte_t
*ptep
)
2241 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2242 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2243 update_mmu_cache(vma
, address
, ptep
);
2247 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2248 struct vm_area_struct
*vma
)
2250 pte_t
*src_pte
, *dst_pte
, entry
;
2251 struct page
*ptepage
;
2254 struct hstate
*h
= hstate_vma(vma
);
2255 unsigned long sz
= huge_page_size(h
);
2257 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2259 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2260 src_pte
= huge_pte_offset(src
, addr
);
2263 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2267 /* If the pagetables are shared don't copy or take references */
2268 if (dst_pte
== src_pte
)
2271 spin_lock(&dst
->page_table_lock
);
2272 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2273 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2275 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2276 entry
= huge_ptep_get(src_pte
);
2277 ptepage
= pte_page(entry
);
2279 page_dup_rmap(ptepage
);
2280 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2282 spin_unlock(&src
->page_table_lock
);
2283 spin_unlock(&dst
->page_table_lock
);
2291 static int is_hugetlb_entry_migration(pte_t pte
)
2295 if (huge_pte_none(pte
) || pte_present(pte
))
2297 swp
= pte_to_swp_entry(pte
);
2298 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2304 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2308 if (huge_pte_none(pte
) || pte_present(pte
))
2310 swp
= pte_to_swp_entry(pte
);
2311 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2317 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2318 unsigned long start
, unsigned long end
,
2319 struct page
*ref_page
)
2321 int force_flush
= 0;
2322 struct mm_struct
*mm
= vma
->vm_mm
;
2323 unsigned long address
;
2327 struct hstate
*h
= hstate_vma(vma
);
2328 unsigned long sz
= huge_page_size(h
);
2330 WARN_ON(!is_vm_hugetlb_page(vma
));
2331 BUG_ON(start
& ~huge_page_mask(h
));
2332 BUG_ON(end
& ~huge_page_mask(h
));
2334 tlb_start_vma(tlb
, vma
);
2335 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2337 spin_lock(&mm
->page_table_lock
);
2338 for (address
= start
; address
< end
; address
+= sz
) {
2339 ptep
= huge_pte_offset(mm
, address
);
2343 if (huge_pmd_unshare(mm
, &address
, ptep
))
2346 pte
= huge_ptep_get(ptep
);
2347 if (huge_pte_none(pte
))
2351 * HWPoisoned hugepage is already unmapped and dropped reference
2353 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
)))
2356 page
= pte_page(pte
);
2358 * If a reference page is supplied, it is because a specific
2359 * page is being unmapped, not a range. Ensure the page we
2360 * are about to unmap is the actual page of interest.
2363 if (page
!= ref_page
)
2367 * Mark the VMA as having unmapped its page so that
2368 * future faults in this VMA will fail rather than
2369 * looking like data was lost
2371 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2374 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2375 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2377 set_page_dirty(page
);
2379 page_remove_rmap(page
);
2380 force_flush
= !__tlb_remove_page(tlb
, page
);
2383 /* Bail out after unmapping reference page if supplied */
2387 spin_unlock(&mm
->page_table_lock
);
2389 * mmu_gather ran out of room to batch pages, we break out of
2390 * the PTE lock to avoid doing the potential expensive TLB invalidate
2391 * and page-free while holding it.
2396 if (address
< end
&& !ref_page
)
2399 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2400 tlb_end_vma(tlb
, vma
);
2403 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2404 unsigned long end
, struct page
*ref_page
)
2406 struct mm_struct
*mm
;
2407 struct mmu_gather tlb
;
2411 tlb_gather_mmu(&tlb
, mm
, 0);
2412 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2413 tlb_finish_mmu(&tlb
, start
, end
);
2417 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2418 * mappping it owns the reserve page for. The intention is to unmap the page
2419 * from other VMAs and let the children be SIGKILLed if they are faulting the
2422 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2423 struct page
*page
, unsigned long address
)
2425 struct hstate
*h
= hstate_vma(vma
);
2426 struct vm_area_struct
*iter_vma
;
2427 struct address_space
*mapping
;
2428 struct prio_tree_iter iter
;
2432 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2433 * from page cache lookup which is in HPAGE_SIZE units.
2435 address
= address
& huge_page_mask(h
);
2436 pgoff
= vma_hugecache_offset(h
, vma
, address
);
2437 mapping
= vma
->vm_file
->f_dentry
->d_inode
->i_mapping
;
2440 * Take the mapping lock for the duration of the table walk. As
2441 * this mapping should be shared between all the VMAs,
2442 * __unmap_hugepage_range() is called as the lock is already held
2444 mutex_lock(&mapping
->i_mmap_mutex
);
2445 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2446 /* Do not unmap the current VMA */
2447 if (iter_vma
== vma
)
2451 * Unmap the page from other VMAs without their own reserves.
2452 * They get marked to be SIGKILLed if they fault in these
2453 * areas. This is because a future no-page fault on this VMA
2454 * could insert a zeroed page instead of the data existing
2455 * from the time of fork. This would look like data corruption
2457 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2458 unmap_hugepage_range(iter_vma
, address
,
2459 address
+ huge_page_size(h
), page
);
2461 mutex_unlock(&mapping
->i_mmap_mutex
);
2467 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2468 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2469 * cannot race with other handlers or page migration.
2470 * Keep the pte_same checks anyway to make transition from the mutex easier.
2472 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2473 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2474 struct page
*pagecache_page
)
2476 struct hstate
*h
= hstate_vma(vma
);
2477 struct page
*old_page
, *new_page
;
2479 int outside_reserve
= 0;
2481 old_page
= pte_page(pte
);
2484 /* If no-one else is actually using this page, avoid the copy
2485 * and just make the page writable */
2486 avoidcopy
= (page_mapcount(old_page
) == 1);
2488 if (PageAnon(old_page
))
2489 page_move_anon_rmap(old_page
, vma
, address
);
2490 set_huge_ptep_writable(vma
, address
, ptep
);
2495 * If the process that created a MAP_PRIVATE mapping is about to
2496 * perform a COW due to a shared page count, attempt to satisfy
2497 * the allocation without using the existing reserves. The pagecache
2498 * page is used to determine if the reserve at this address was
2499 * consumed or not. If reserves were used, a partial faulted mapping
2500 * at the time of fork() could consume its reserves on COW instead
2501 * of the full address range.
2503 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2504 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2505 old_page
!= pagecache_page
)
2506 outside_reserve
= 1;
2508 page_cache_get(old_page
);
2510 /* Drop page_table_lock as buddy allocator may be called */
2511 spin_unlock(&mm
->page_table_lock
);
2512 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2514 if (IS_ERR(new_page
)) {
2515 long err
= PTR_ERR(new_page
);
2516 page_cache_release(old_page
);
2519 * If a process owning a MAP_PRIVATE mapping fails to COW,
2520 * it is due to references held by a child and an insufficient
2521 * huge page pool. To guarantee the original mappers
2522 * reliability, unmap the page from child processes. The child
2523 * may get SIGKILLed if it later faults.
2525 if (outside_reserve
) {
2526 BUG_ON(huge_pte_none(pte
));
2527 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2528 BUG_ON(huge_pte_none(pte
));
2529 spin_lock(&mm
->page_table_lock
);
2530 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2531 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2532 goto retry_avoidcopy
;
2534 * race occurs while re-acquiring page_table_lock, and
2542 /* Caller expects lock to be held */
2543 spin_lock(&mm
->page_table_lock
);
2545 return VM_FAULT_OOM
;
2547 return VM_FAULT_SIGBUS
;
2551 * When the original hugepage is shared one, it does not have
2552 * anon_vma prepared.
2554 if (unlikely(anon_vma_prepare(vma
))) {
2555 page_cache_release(new_page
);
2556 page_cache_release(old_page
);
2557 /* Caller expects lock to be held */
2558 spin_lock(&mm
->page_table_lock
);
2559 return VM_FAULT_OOM
;
2562 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2563 pages_per_huge_page(h
));
2564 __SetPageUptodate(new_page
);
2567 * Retake the page_table_lock to check for racing updates
2568 * before the page tables are altered
2570 spin_lock(&mm
->page_table_lock
);
2571 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2572 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2574 mmu_notifier_invalidate_range_start(mm
,
2575 address
& huge_page_mask(h
),
2576 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2577 huge_ptep_clear_flush(vma
, address
, ptep
);
2578 set_huge_pte_at(mm
, address
, ptep
,
2579 make_huge_pte(vma
, new_page
, 1));
2580 page_remove_rmap(old_page
);
2581 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2582 /* Make the old page be freed below */
2583 new_page
= old_page
;
2584 mmu_notifier_invalidate_range_end(mm
,
2585 address
& huge_page_mask(h
),
2586 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2588 page_cache_release(new_page
);
2589 page_cache_release(old_page
);
2593 /* Return the pagecache page at a given address within a VMA */
2594 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2595 struct vm_area_struct
*vma
, unsigned long address
)
2597 struct address_space
*mapping
;
2600 mapping
= vma
->vm_file
->f_mapping
;
2601 idx
= vma_hugecache_offset(h
, vma
, address
);
2603 return find_lock_page(mapping
, idx
);
2607 * Return whether there is a pagecache page to back given address within VMA.
2608 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2610 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2611 struct vm_area_struct
*vma
, unsigned long address
)
2613 struct address_space
*mapping
;
2617 mapping
= vma
->vm_file
->f_mapping
;
2618 idx
= vma_hugecache_offset(h
, vma
, address
);
2620 page
= find_get_page(mapping
, idx
);
2623 return page
!= NULL
;
2626 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2627 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2629 struct hstate
*h
= hstate_vma(vma
);
2630 int ret
= VM_FAULT_SIGBUS
;
2635 struct address_space
*mapping
;
2639 * Currently, we are forced to kill the process in the event the
2640 * original mapper has unmapped pages from the child due to a failed
2641 * COW. Warn that such a situation has occurred as it may not be obvious
2643 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2645 "PID %d killed due to inadequate hugepage pool\n",
2650 mapping
= vma
->vm_file
->f_mapping
;
2651 idx
= vma_hugecache_offset(h
, vma
, address
);
2654 * Use page lock to guard against racing truncation
2655 * before we get page_table_lock.
2658 page
= find_lock_page(mapping
, idx
);
2660 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2663 page
= alloc_huge_page(vma
, address
, 0);
2665 ret
= PTR_ERR(page
);
2669 ret
= VM_FAULT_SIGBUS
;
2672 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2673 __SetPageUptodate(page
);
2675 if (vma
->vm_flags
& VM_MAYSHARE
) {
2677 struct inode
*inode
= mapping
->host
;
2679 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2687 spin_lock(&inode
->i_lock
);
2688 inode
->i_blocks
+= blocks_per_huge_page(h
);
2689 spin_unlock(&inode
->i_lock
);
2692 if (unlikely(anon_vma_prepare(vma
))) {
2694 goto backout_unlocked
;
2700 * If memory error occurs between mmap() and fault, some process
2701 * don't have hwpoisoned swap entry for errored virtual address.
2702 * So we need to block hugepage fault by PG_hwpoison bit check.
2704 if (unlikely(PageHWPoison(page
))) {
2705 ret
= VM_FAULT_HWPOISON
|
2706 VM_FAULT_SET_HINDEX(hstate_index(h
));
2707 goto backout_unlocked
;
2712 * If we are going to COW a private mapping later, we examine the
2713 * pending reservations for this page now. This will ensure that
2714 * any allocations necessary to record that reservation occur outside
2717 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2718 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2720 goto backout_unlocked
;
2723 spin_lock(&mm
->page_table_lock
);
2724 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2729 if (!huge_pte_none(huge_ptep_get(ptep
)))
2733 hugepage_add_new_anon_rmap(page
, vma
, address
);
2735 page_dup_rmap(page
);
2736 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2737 && (vma
->vm_flags
& VM_SHARED
)));
2738 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2740 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2741 /* Optimization, do the COW without a second fault */
2742 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2745 spin_unlock(&mm
->page_table_lock
);
2751 spin_unlock(&mm
->page_table_lock
);
2758 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2759 unsigned long address
, unsigned int flags
)
2764 struct page
*page
= NULL
;
2765 struct page
*pagecache_page
= NULL
;
2766 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2767 struct hstate
*h
= hstate_vma(vma
);
2769 address
&= huge_page_mask(h
);
2771 ptep
= huge_pte_offset(mm
, address
);
2773 entry
= huge_ptep_get(ptep
);
2774 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2775 migration_entry_wait(mm
, (pmd_t
*)ptep
, address
);
2777 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2778 return VM_FAULT_HWPOISON_LARGE
|
2779 VM_FAULT_SET_HINDEX(hstate_index(h
));
2782 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2784 return VM_FAULT_OOM
;
2787 * Serialize hugepage allocation and instantiation, so that we don't
2788 * get spurious allocation failures if two CPUs race to instantiate
2789 * the same page in the page cache.
2791 mutex_lock(&hugetlb_instantiation_mutex
);
2792 entry
= huge_ptep_get(ptep
);
2793 if (huge_pte_none(entry
)) {
2794 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2801 * If we are going to COW the mapping later, we examine the pending
2802 * reservations for this page now. This will ensure that any
2803 * allocations necessary to record that reservation occur outside the
2804 * spinlock. For private mappings, we also lookup the pagecache
2805 * page now as it is used to determine if a reservation has been
2808 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2809 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2814 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2815 pagecache_page
= hugetlbfs_pagecache_page(h
,
2820 * hugetlb_cow() requires page locks of pte_page(entry) and
2821 * pagecache_page, so here we need take the former one
2822 * when page != pagecache_page or !pagecache_page.
2823 * Note that locking order is always pagecache_page -> page,
2824 * so no worry about deadlock.
2826 page
= pte_page(entry
);
2828 if (page
!= pagecache_page
)
2831 spin_lock(&mm
->page_table_lock
);
2832 /* Check for a racing update before calling hugetlb_cow */
2833 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2834 goto out_page_table_lock
;
2837 if (flags
& FAULT_FLAG_WRITE
) {
2838 if (!pte_write(entry
)) {
2839 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2841 goto out_page_table_lock
;
2843 entry
= pte_mkdirty(entry
);
2845 entry
= pte_mkyoung(entry
);
2846 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2847 flags
& FAULT_FLAG_WRITE
))
2848 update_mmu_cache(vma
, address
, ptep
);
2850 out_page_table_lock
:
2851 spin_unlock(&mm
->page_table_lock
);
2853 if (pagecache_page
) {
2854 unlock_page(pagecache_page
);
2855 put_page(pagecache_page
);
2857 if (page
!= pagecache_page
)
2862 mutex_unlock(&hugetlb_instantiation_mutex
);
2867 /* Can be overriden by architectures */
2868 __attribute__((weak
)) struct page
*
2869 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2870 pud_t
*pud
, int write
)
2876 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2877 struct page
**pages
, struct vm_area_struct
**vmas
,
2878 unsigned long *position
, int *length
, int i
,
2881 unsigned long pfn_offset
;
2882 unsigned long vaddr
= *position
;
2883 int remainder
= *length
;
2884 struct hstate
*h
= hstate_vma(vma
);
2886 spin_lock(&mm
->page_table_lock
);
2887 while (vaddr
< vma
->vm_end
&& remainder
) {
2893 * Some archs (sparc64, sh*) have multiple pte_ts to
2894 * each hugepage. We have to make sure we get the
2895 * first, for the page indexing below to work.
2897 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2898 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2901 * When coredumping, it suits get_dump_page if we just return
2902 * an error where there's an empty slot with no huge pagecache
2903 * to back it. This way, we avoid allocating a hugepage, and
2904 * the sparse dumpfile avoids allocating disk blocks, but its
2905 * huge holes still show up with zeroes where they need to be.
2907 if (absent
&& (flags
& FOLL_DUMP
) &&
2908 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2914 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2917 spin_unlock(&mm
->page_table_lock
);
2918 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2919 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2920 spin_lock(&mm
->page_table_lock
);
2921 if (!(ret
& VM_FAULT_ERROR
))
2928 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2929 page
= pte_page(huge_ptep_get(pte
));
2932 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2943 if (vaddr
< vma
->vm_end
&& remainder
&&
2944 pfn_offset
< pages_per_huge_page(h
)) {
2946 * We use pfn_offset to avoid touching the pageframes
2947 * of this compound page.
2952 spin_unlock(&mm
->page_table_lock
);
2953 *length
= remainder
;
2956 return i
? i
: -EFAULT
;
2959 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2960 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2962 struct mm_struct
*mm
= vma
->vm_mm
;
2963 unsigned long start
= address
;
2966 struct hstate
*h
= hstate_vma(vma
);
2968 BUG_ON(address
>= end
);
2969 flush_cache_range(vma
, address
, end
);
2971 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2972 spin_lock(&mm
->page_table_lock
);
2973 for (; address
< end
; address
+= huge_page_size(h
)) {
2974 ptep
= huge_pte_offset(mm
, address
);
2977 if (huge_pmd_unshare(mm
, &address
, ptep
))
2979 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2980 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2981 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2982 set_huge_pte_at(mm
, address
, ptep
, pte
);
2985 spin_unlock(&mm
->page_table_lock
);
2986 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2988 flush_tlb_range(vma
, start
, end
);
2991 int hugetlb_reserve_pages(struct inode
*inode
,
2993 struct vm_area_struct
*vma
,
2994 vm_flags_t vm_flags
)
2997 struct hstate
*h
= hstate_inode(inode
);
2998 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3001 * Only apply hugepage reservation if asked. At fault time, an
3002 * attempt will be made for VM_NORESERVE to allocate a page
3003 * without using reserves
3005 if (vm_flags
& VM_NORESERVE
)
3009 * Shared mappings base their reservation on the number of pages that
3010 * are already allocated on behalf of the file. Private mappings need
3011 * to reserve the full area even if read-only as mprotect() may be
3012 * called to make the mapping read-write. Assume !vma is a shm mapping
3014 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3015 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3017 struct resv_map
*resv_map
= resv_map_alloc();
3023 set_vma_resv_map(vma
, resv_map
);
3024 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3032 /* There must be enough pages in the subpool for the mapping */
3033 if (hugepage_subpool_get_pages(spool
, chg
)) {
3039 * Check enough hugepages are available for the reservation.
3040 * Hand the pages back to the subpool if there are not
3042 ret
= hugetlb_acct_memory(h
, chg
);
3044 hugepage_subpool_put_pages(spool
, chg
);
3049 * Account for the reservations made. Shared mappings record regions
3050 * that have reservations as they are shared by multiple VMAs.
3051 * When the last VMA disappears, the region map says how much
3052 * the reservation was and the page cache tells how much of
3053 * the reservation was consumed. Private mappings are per-VMA and
3054 * only the consumed reservations are tracked. When the VMA
3055 * disappears, the original reservation is the VMA size and the
3056 * consumed reservations are stored in the map. Hence, nothing
3057 * else has to be done for private mappings here
3059 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3060 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3068 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3070 struct hstate
*h
= hstate_inode(inode
);
3071 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3072 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3074 spin_lock(&inode
->i_lock
);
3075 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3076 spin_unlock(&inode
->i_lock
);
3078 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3079 hugetlb_acct_memory(h
, -(chg
- freed
));
3082 #ifdef CONFIG_MEMORY_FAILURE
3084 /* Should be called in hugetlb_lock */
3085 static int is_hugepage_on_freelist(struct page
*hpage
)
3089 struct hstate
*h
= page_hstate(hpage
);
3090 int nid
= page_to_nid(hpage
);
3092 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3099 * This function is called from memory failure code.
3100 * Assume the caller holds page lock of the head page.
3102 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3104 struct hstate
*h
= page_hstate(hpage
);
3105 int nid
= page_to_nid(hpage
);
3108 spin_lock(&hugetlb_lock
);
3109 if (is_hugepage_on_freelist(hpage
)) {
3110 list_del(&hpage
->lru
);
3111 set_page_refcounted(hpage
);
3112 h
->free_huge_pages
--;
3113 h
->free_huge_pages_node
[nid
]--;
3116 spin_unlock(&hugetlb_lock
);