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/node.h>
34 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
35 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
36 unsigned long hugepages_treat_as_movable
;
38 static int hugetlb_max_hstate
;
39 unsigned int default_hstate_idx
;
40 struct hstate hstates
[HUGE_MAX_HSTATE
];
42 __initdata
LIST_HEAD(huge_boot_pages
);
44 /* for command line parsing */
45 static struct hstate
* __initdata parsed_hstate
;
46 static unsigned long __initdata default_hstate_max_huge_pages
;
47 static unsigned long __initdata default_hstate_size
;
49 #define for_each_hstate(h) \
50 for ((h) = hstates; (h) < &hstates[hugetlb_max_hstate]; (h)++)
53 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
55 static DEFINE_SPINLOCK(hugetlb_lock
);
57 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
59 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
61 spin_unlock(&spool
->lock
);
63 /* If no pages are used, and no other handles to the subpool
64 * remain, free the subpool the subpool remain */
69 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
71 struct hugepage_subpool
*spool
;
73 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
77 spin_lock_init(&spool
->lock
);
79 spool
->max_hpages
= nr_blocks
;
80 spool
->used_hpages
= 0;
85 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
87 spin_lock(&spool
->lock
);
88 BUG_ON(!spool
->count
);
90 unlock_or_release_subpool(spool
);
93 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
101 spin_lock(&spool
->lock
);
102 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
103 spool
->used_hpages
+= delta
;
107 spin_unlock(&spool
->lock
);
112 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
118 spin_lock(&spool
->lock
);
119 spool
->used_hpages
-= delta
;
120 /* If hugetlbfs_put_super couldn't free spool due to
121 * an outstanding quota reference, free it now. */
122 unlock_or_release_subpool(spool
);
125 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
127 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
130 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
132 return subpool_inode(vma
->vm_file
->f_dentry
->d_inode
);
136 * Region tracking -- allows tracking of reservations and instantiated pages
137 * across the pages in a mapping.
139 * The region data structures are protected by a combination of the mmap_sem
140 * and the hugetlb_instantion_mutex. To access or modify a region the caller
141 * must either hold the mmap_sem for write, or the mmap_sem for read and
142 * the hugetlb_instantiation mutex:
144 * down_write(&mm->mmap_sem);
146 * down_read(&mm->mmap_sem);
147 * mutex_lock(&hugetlb_instantiation_mutex);
150 struct list_head link
;
155 static long region_add(struct list_head
*head
, long f
, long t
)
157 struct file_region
*rg
, *nrg
, *trg
;
159 /* Locate the region we are either in or before. */
160 list_for_each_entry(rg
, head
, link
)
164 /* Round our left edge to the current segment if it encloses us. */
168 /* Check for and consume any regions we now overlap with. */
170 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
171 if (&rg
->link
== head
)
176 /* If this area reaches higher then extend our area to
177 * include it completely. If this is not the first area
178 * which we intend to reuse, free it. */
191 static long region_chg(struct list_head
*head
, long f
, long t
)
193 struct file_region
*rg
, *nrg
;
196 /* Locate the region we are before or in. */
197 list_for_each_entry(rg
, head
, link
)
201 /* If we are below the current region then a new region is required.
202 * Subtle, allocate a new region at the position but make it zero
203 * size such that we can guarantee to record the reservation. */
204 if (&rg
->link
== head
|| t
< rg
->from
) {
205 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
210 INIT_LIST_HEAD(&nrg
->link
);
211 list_add(&nrg
->link
, rg
->link
.prev
);
216 /* Round our left edge to the current segment if it encloses us. */
221 /* Check for and consume any regions we now overlap with. */
222 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
223 if (&rg
->link
== head
)
228 /* We overlap with this area, if it extends further than
229 * us then we must extend ourselves. Account for its
230 * existing reservation. */
235 chg
-= rg
->to
- rg
->from
;
240 static long region_truncate(struct list_head
*head
, long end
)
242 struct file_region
*rg
, *trg
;
245 /* Locate the region we are either in or before. */
246 list_for_each_entry(rg
, head
, link
)
249 if (&rg
->link
== head
)
252 /* If we are in the middle of a region then adjust it. */
253 if (end
> rg
->from
) {
256 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
259 /* Drop any remaining regions. */
260 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
261 if (&rg
->link
== head
)
263 chg
+= rg
->to
- rg
->from
;
270 static long region_count(struct list_head
*head
, long f
, long t
)
272 struct file_region
*rg
;
275 /* Locate each segment we overlap with, and count that overlap. */
276 list_for_each_entry(rg
, head
, link
) {
285 seg_from
= max(rg
->from
, f
);
286 seg_to
= min(rg
->to
, t
);
288 chg
+= seg_to
- seg_from
;
295 * Convert the address within this vma to the page offset within
296 * the mapping, in pagecache page units; huge pages here.
298 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
299 struct vm_area_struct
*vma
, unsigned long address
)
301 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
302 (vma
->vm_pgoff
>> huge_page_order(h
));
305 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
306 unsigned long address
)
308 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
312 * Return the size of the pages allocated when backing a VMA. In the majority
313 * cases this will be same size as used by the page table entries.
315 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
317 struct hstate
*hstate
;
319 if (!is_vm_hugetlb_page(vma
))
322 hstate
= hstate_vma(vma
);
324 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
326 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
329 * Return the page size being used by the MMU to back a VMA. In the majority
330 * of cases, the page size used by the kernel matches the MMU size. On
331 * architectures where it differs, an architecture-specific version of this
332 * function is required.
334 #ifndef vma_mmu_pagesize
335 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
337 return vma_kernel_pagesize(vma
);
342 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
343 * bits of the reservation map pointer, which are always clear due to
346 #define HPAGE_RESV_OWNER (1UL << 0)
347 #define HPAGE_RESV_UNMAPPED (1UL << 1)
348 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
351 * These helpers are used to track how many pages are reserved for
352 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
353 * is guaranteed to have their future faults succeed.
355 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
356 * the reserve counters are updated with the hugetlb_lock held. It is safe
357 * to reset the VMA at fork() time as it is not in use yet and there is no
358 * chance of the global counters getting corrupted as a result of the values.
360 * The private mapping reservation is represented in a subtly different
361 * manner to a shared mapping. A shared mapping has a region map associated
362 * with the underlying file, this region map represents the backing file
363 * pages which have ever had a reservation assigned which this persists even
364 * after the page is instantiated. A private mapping has a region map
365 * associated with the original mmap which is attached to all VMAs which
366 * reference it, this region map represents those offsets which have consumed
367 * reservation ie. where pages have been instantiated.
369 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
371 return (unsigned long)vma
->vm_private_data
;
374 static void set_vma_private_data(struct vm_area_struct
*vma
,
377 vma
->vm_private_data
= (void *)value
;
382 struct list_head regions
;
385 static struct resv_map
*resv_map_alloc(void)
387 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
391 kref_init(&resv_map
->refs
);
392 INIT_LIST_HEAD(&resv_map
->regions
);
397 static void resv_map_release(struct kref
*ref
)
399 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
401 /* Clear out any active regions before we release the map. */
402 region_truncate(&resv_map
->regions
, 0);
406 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
408 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
409 if (!(vma
->vm_flags
& VM_MAYSHARE
))
410 return (struct resv_map
*)(get_vma_private_data(vma
) &
415 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
417 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
418 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
420 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
421 HPAGE_RESV_MASK
) | (unsigned long)map
);
424 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
426 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
427 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
429 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
432 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
434 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
436 return (get_vma_private_data(vma
) & flag
) != 0;
439 /* Decrement the reserved pages in the hugepage pool by one */
440 static void decrement_hugepage_resv_vma(struct hstate
*h
,
441 struct vm_area_struct
*vma
)
443 if (vma
->vm_flags
& VM_NORESERVE
)
446 if (vma
->vm_flags
& VM_MAYSHARE
) {
447 /* Shared mappings always use reserves */
448 h
->resv_huge_pages
--;
449 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
451 * Only the process that called mmap() has reserves for
454 h
->resv_huge_pages
--;
458 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
459 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
461 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
462 if (!(vma
->vm_flags
& VM_MAYSHARE
))
463 vma
->vm_private_data
= (void *)0;
466 /* Returns true if the VMA has associated reserve pages */
467 static int vma_has_reserves(struct vm_area_struct
*vma
)
469 if (vma
->vm_flags
& VM_MAYSHARE
)
471 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
476 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
479 struct hstate
*h
= page_hstate(src
);
480 struct page
*dst_base
= dst
;
481 struct page
*src_base
= src
;
483 for (i
= 0; i
< pages_per_huge_page(h
); ) {
485 copy_highpage(dst
, src
);
488 dst
= mem_map_next(dst
, dst_base
, i
);
489 src
= mem_map_next(src
, src_base
, i
);
493 void copy_huge_page(struct page
*dst
, struct page
*src
)
496 struct hstate
*h
= page_hstate(src
);
498 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
499 copy_gigantic_page(dst
, src
);
504 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
506 copy_highpage(dst
+ i
, src
+ i
);
510 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
512 int nid
= page_to_nid(page
);
513 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
514 h
->free_huge_pages
++;
515 h
->free_huge_pages_node
[nid
]++;
518 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
522 if (list_empty(&h
->hugepage_freelists
[nid
]))
524 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
525 list_move(&page
->lru
, &h
->hugepage_activelist
);
526 set_page_refcounted(page
);
527 h
->free_huge_pages
--;
528 h
->free_huge_pages_node
[nid
]--;
532 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
533 struct vm_area_struct
*vma
,
534 unsigned long address
, int avoid_reserve
)
536 struct page
*page
= NULL
;
537 struct mempolicy
*mpol
;
538 nodemask_t
*nodemask
;
539 struct zonelist
*zonelist
;
542 unsigned int cpuset_mems_cookie
;
545 cpuset_mems_cookie
= get_mems_allowed();
546 zonelist
= huge_zonelist(vma
, address
,
547 htlb_alloc_mask
, &mpol
, &nodemask
);
549 * A child process with MAP_PRIVATE mappings created by their parent
550 * have no page reserves. This check ensures that reservations are
551 * not "stolen". The child may still get SIGKILLed
553 if (!vma_has_reserves(vma
) &&
554 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
557 /* If reserves cannot be used, ensure enough pages are in the pool */
558 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
561 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
562 MAX_NR_ZONES
- 1, nodemask
) {
563 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
564 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
567 decrement_hugepage_resv_vma(h
, vma
);
574 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
583 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
587 VM_BUG_ON(h
->order
>= MAX_ORDER
);
590 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
591 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
592 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
593 1 << PG_referenced
| 1 << PG_dirty
|
594 1 << PG_active
| 1 << PG_reserved
|
595 1 << PG_private
| 1 << PG_writeback
);
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 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
632 /* remove the page from active list */
633 list_del(&page
->lru
);
634 update_and_free_page(h
, page
);
635 h
->surplus_huge_pages
--;
636 h
->surplus_huge_pages_node
[nid
]--;
638 enqueue_huge_page(h
, page
);
640 spin_unlock(&hugetlb_lock
);
641 hugepage_subpool_put_pages(spool
, 1);
644 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
646 INIT_LIST_HEAD(&page
->lru
);
647 set_compound_page_dtor(page
, free_huge_page
);
648 spin_lock(&hugetlb_lock
);
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
);
899 * We incremented the global counters already
901 h
->nr_huge_pages_node
[r_nid
]++;
902 h
->surplus_huge_pages_node
[r_nid
]++;
903 __count_vm_event(HTLB_BUDDY_PGALLOC
);
906 h
->surplus_huge_pages
--;
907 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
909 spin_unlock(&hugetlb_lock
);
915 * This allocation function is useful in the context where vma is irrelevant.
916 * E.g. soft-offlining uses this function because it only cares physical
917 * address of error page.
919 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
923 spin_lock(&hugetlb_lock
);
924 page
= dequeue_huge_page_node(h
, nid
);
925 spin_unlock(&hugetlb_lock
);
928 page
= alloc_buddy_huge_page(h
, nid
);
934 * Increase the hugetlb pool such that it can accommodate a reservation
937 static int gather_surplus_pages(struct hstate
*h
, int delta
)
939 struct list_head surplus_list
;
940 struct page
*page
, *tmp
;
942 int needed
, allocated
;
943 bool alloc_ok
= true;
945 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
947 h
->resv_huge_pages
+= delta
;
952 INIT_LIST_HEAD(&surplus_list
);
956 spin_unlock(&hugetlb_lock
);
957 for (i
= 0; i
< needed
; i
++) {
958 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
963 list_add(&page
->lru
, &surplus_list
);
968 * After retaking hugetlb_lock, we need to recalculate 'needed'
969 * because either resv_huge_pages or free_huge_pages may have changed.
971 spin_lock(&hugetlb_lock
);
972 needed
= (h
->resv_huge_pages
+ delta
) -
973 (h
->free_huge_pages
+ allocated
);
978 * We were not able to allocate enough pages to
979 * satisfy the entire reservation so we free what
980 * we've allocated so far.
985 * The surplus_list now contains _at_least_ the number of extra pages
986 * needed to accommodate the reservation. Add the appropriate number
987 * of pages to the hugetlb pool and free the extras back to the buddy
988 * allocator. Commit the entire reservation here to prevent another
989 * process from stealing the pages as they are added to the pool but
990 * before they are reserved.
993 h
->resv_huge_pages
+= delta
;
996 /* Free the needed pages to the hugetlb pool */
997 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1001 * This page is now managed by the hugetlb allocator and has
1002 * no users -- drop the buddy allocator's reference.
1004 put_page_testzero(page
);
1005 VM_BUG_ON(page_count(page
));
1006 enqueue_huge_page(h
, page
);
1009 spin_unlock(&hugetlb_lock
);
1011 /* Free unnecessary surplus pages to the buddy allocator */
1012 if (!list_empty(&surplus_list
)) {
1013 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1017 spin_lock(&hugetlb_lock
);
1023 * When releasing a hugetlb pool reservation, any surplus pages that were
1024 * allocated to satisfy the reservation must be explicitly freed if they were
1026 * Called with hugetlb_lock held.
1028 static void return_unused_surplus_pages(struct hstate
*h
,
1029 unsigned long unused_resv_pages
)
1031 unsigned long nr_pages
;
1033 /* Uncommit the reservation */
1034 h
->resv_huge_pages
-= unused_resv_pages
;
1036 /* Cannot return gigantic pages currently */
1037 if (h
->order
>= MAX_ORDER
)
1040 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1043 * We want to release as many surplus pages as possible, spread
1044 * evenly across all nodes with memory. Iterate across these nodes
1045 * until we can no longer free unreserved surplus pages. This occurs
1046 * when the nodes with surplus pages have no free pages.
1047 * free_pool_huge_page() will balance the the freed pages across the
1048 * on-line nodes with memory and will handle the hstate accounting.
1050 while (nr_pages
--) {
1051 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
1057 * Determine if the huge page at addr within the vma has an associated
1058 * reservation. Where it does not we will need to logically increase
1059 * reservation and actually increase subpool usage before an allocation
1060 * can occur. Where any new reservation would be required the
1061 * reservation change is prepared, but not committed. Once the page
1062 * has been allocated from the subpool and instantiated the change should
1063 * be committed via vma_commit_reservation. No action is required on
1066 static long vma_needs_reservation(struct hstate
*h
,
1067 struct vm_area_struct
*vma
, unsigned long addr
)
1069 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1070 struct inode
*inode
= mapping
->host
;
1072 if (vma
->vm_flags
& VM_MAYSHARE
) {
1073 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1074 return region_chg(&inode
->i_mapping
->private_list
,
1077 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1082 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1083 struct resv_map
*reservations
= vma_resv_map(vma
);
1085 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1091 static void vma_commit_reservation(struct hstate
*h
,
1092 struct vm_area_struct
*vma
, unsigned long addr
)
1094 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1095 struct inode
*inode
= mapping
->host
;
1097 if (vma
->vm_flags
& VM_MAYSHARE
) {
1098 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1099 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1101 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1102 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1103 struct resv_map
*reservations
= vma_resv_map(vma
);
1105 /* Mark this page used in the map. */
1106 region_add(&reservations
->regions
, idx
, idx
+ 1);
1110 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1111 unsigned long addr
, int avoid_reserve
)
1113 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1114 struct hstate
*h
= hstate_vma(vma
);
1119 * Processes that did not create the mapping will have no
1120 * reserves and will not have accounted against subpool
1121 * limit. Check that the subpool limit can be made before
1122 * satisfying the allocation MAP_NORESERVE mappings may also
1123 * need pages and subpool limit allocated allocated if no reserve
1126 chg
= vma_needs_reservation(h
, vma
, addr
);
1128 return ERR_PTR(-ENOMEM
);
1130 if (hugepage_subpool_get_pages(spool
, chg
))
1131 return ERR_PTR(-ENOSPC
);
1133 spin_lock(&hugetlb_lock
);
1134 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1135 spin_unlock(&hugetlb_lock
);
1138 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1140 hugepage_subpool_put_pages(spool
, chg
);
1141 return ERR_PTR(-ENOSPC
);
1145 set_page_private(page
, (unsigned long)spool
);
1147 vma_commit_reservation(h
, vma
, addr
);
1152 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1154 struct huge_bootmem_page
*m
;
1155 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1160 addr
= __alloc_bootmem_node_nopanic(
1161 NODE_DATA(hstate_next_node_to_alloc(h
,
1162 &node_states
[N_HIGH_MEMORY
])),
1163 huge_page_size(h
), huge_page_size(h
), 0);
1167 * Use the beginning of the huge page to store the
1168 * huge_bootmem_page struct (until gather_bootmem
1169 * puts them into the mem_map).
1179 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1180 /* Put them into a private list first because mem_map is not up yet */
1181 list_add(&m
->list
, &huge_boot_pages
);
1186 static void prep_compound_huge_page(struct page
*page
, int order
)
1188 if (unlikely(order
> (MAX_ORDER
- 1)))
1189 prep_compound_gigantic_page(page
, order
);
1191 prep_compound_page(page
, order
);
1194 /* Put bootmem huge pages into the standard lists after mem_map is up */
1195 static void __init
gather_bootmem_prealloc(void)
1197 struct huge_bootmem_page
*m
;
1199 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1200 struct hstate
*h
= m
->hstate
;
1203 #ifdef CONFIG_HIGHMEM
1204 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1205 free_bootmem_late((unsigned long)m
,
1206 sizeof(struct huge_bootmem_page
));
1208 page
= virt_to_page(m
);
1210 __ClearPageReserved(page
);
1211 WARN_ON(page_count(page
) != 1);
1212 prep_compound_huge_page(page
, h
->order
);
1213 prep_new_huge_page(h
, page
, page_to_nid(page
));
1215 * If we had gigantic hugepages allocated at boot time, we need
1216 * to restore the 'stolen' pages to totalram_pages in order to
1217 * fix confusing memory reports from free(1) and another
1218 * side-effects, like CommitLimit going negative.
1220 if (h
->order
> (MAX_ORDER
- 1))
1221 totalram_pages
+= 1 << h
->order
;
1225 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1229 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1230 if (h
->order
>= MAX_ORDER
) {
1231 if (!alloc_bootmem_huge_page(h
))
1233 } else if (!alloc_fresh_huge_page(h
,
1234 &node_states
[N_HIGH_MEMORY
]))
1237 h
->max_huge_pages
= i
;
1240 static void __init
hugetlb_init_hstates(void)
1244 for_each_hstate(h
) {
1245 /* oversize hugepages were init'ed in early boot */
1246 if (h
->order
< MAX_ORDER
)
1247 hugetlb_hstate_alloc_pages(h
);
1251 static char * __init
memfmt(char *buf
, unsigned long n
)
1253 if (n
>= (1UL << 30))
1254 sprintf(buf
, "%lu GB", n
>> 30);
1255 else if (n
>= (1UL << 20))
1256 sprintf(buf
, "%lu MB", n
>> 20);
1258 sprintf(buf
, "%lu KB", n
>> 10);
1262 static void __init
report_hugepages(void)
1266 for_each_hstate(h
) {
1268 printk(KERN_INFO
"HugeTLB registered %s page size, "
1269 "pre-allocated %ld pages\n",
1270 memfmt(buf
, huge_page_size(h
)),
1271 h
->free_huge_pages
);
1275 #ifdef CONFIG_HIGHMEM
1276 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1277 nodemask_t
*nodes_allowed
)
1281 if (h
->order
>= MAX_ORDER
)
1284 for_each_node_mask(i
, *nodes_allowed
) {
1285 struct page
*page
, *next
;
1286 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1287 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1288 if (count
>= h
->nr_huge_pages
)
1290 if (PageHighMem(page
))
1292 list_del(&page
->lru
);
1293 update_and_free_page(h
, page
);
1294 h
->free_huge_pages
--;
1295 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1300 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1301 nodemask_t
*nodes_allowed
)
1307 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1308 * balanced by operating on them in a round-robin fashion.
1309 * Returns 1 if an adjustment was made.
1311 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1314 int start_nid
, next_nid
;
1317 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1320 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1322 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1323 next_nid
= start_nid
;
1329 * To shrink on this node, there must be a surplus page
1331 if (!h
->surplus_huge_pages_node
[nid
]) {
1332 next_nid
= hstate_next_node_to_alloc(h
,
1339 * Surplus cannot exceed the total number of pages
1341 if (h
->surplus_huge_pages_node
[nid
] >=
1342 h
->nr_huge_pages_node
[nid
]) {
1343 next_nid
= hstate_next_node_to_free(h
,
1349 h
->surplus_huge_pages
+= delta
;
1350 h
->surplus_huge_pages_node
[nid
] += delta
;
1353 } while (next_nid
!= start_nid
);
1358 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1359 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1360 nodemask_t
*nodes_allowed
)
1362 unsigned long min_count
, ret
;
1364 if (h
->order
>= MAX_ORDER
)
1365 return h
->max_huge_pages
;
1368 * Increase the pool size
1369 * First take pages out of surplus state. Then make up the
1370 * remaining difference by allocating fresh huge pages.
1372 * We might race with alloc_buddy_huge_page() here and be unable
1373 * to convert a surplus huge page to a normal huge page. That is
1374 * not critical, though, it just means the overall size of the
1375 * pool might be one hugepage larger than it needs to be, but
1376 * within all the constraints specified by the sysctls.
1378 spin_lock(&hugetlb_lock
);
1379 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1380 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1384 while (count
> persistent_huge_pages(h
)) {
1386 * If this allocation races such that we no longer need the
1387 * page, free_huge_page will handle it by freeing the page
1388 * and reducing the surplus.
1390 spin_unlock(&hugetlb_lock
);
1391 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1392 spin_lock(&hugetlb_lock
);
1396 /* Bail for signals. Probably ctrl-c from user */
1397 if (signal_pending(current
))
1402 * Decrease the pool size
1403 * First return free pages to the buddy allocator (being careful
1404 * to keep enough around to satisfy reservations). Then place
1405 * pages into surplus state as needed so the pool will shrink
1406 * to the desired size as pages become free.
1408 * By placing pages into the surplus state independent of the
1409 * overcommit value, we are allowing the surplus pool size to
1410 * exceed overcommit. There are few sane options here. Since
1411 * alloc_buddy_huge_page() is checking the global counter,
1412 * though, we'll note that we're not allowed to exceed surplus
1413 * and won't grow the pool anywhere else. Not until one of the
1414 * sysctls are changed, or the surplus pages go out of use.
1416 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1417 min_count
= max(count
, min_count
);
1418 try_to_free_low(h
, min_count
, nodes_allowed
);
1419 while (min_count
< persistent_huge_pages(h
)) {
1420 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1423 while (count
< persistent_huge_pages(h
)) {
1424 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1428 ret
= persistent_huge_pages(h
);
1429 spin_unlock(&hugetlb_lock
);
1433 #define HSTATE_ATTR_RO(_name) \
1434 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1436 #define HSTATE_ATTR(_name) \
1437 static struct kobj_attribute _name##_attr = \
1438 __ATTR(_name, 0644, _name##_show, _name##_store)
1440 static struct kobject
*hugepages_kobj
;
1441 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1443 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1445 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1449 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1450 if (hstate_kobjs
[i
] == kobj
) {
1452 *nidp
= NUMA_NO_NODE
;
1456 return kobj_to_node_hstate(kobj
, nidp
);
1459 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1460 struct kobj_attribute
*attr
, char *buf
)
1463 unsigned long nr_huge_pages
;
1466 h
= kobj_to_hstate(kobj
, &nid
);
1467 if (nid
== NUMA_NO_NODE
)
1468 nr_huge_pages
= h
->nr_huge_pages
;
1470 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1472 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1475 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1476 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1477 const char *buf
, size_t len
)
1481 unsigned long count
;
1483 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1485 err
= strict_strtoul(buf
, 10, &count
);
1489 h
= kobj_to_hstate(kobj
, &nid
);
1490 if (h
->order
>= MAX_ORDER
) {
1495 if (nid
== NUMA_NO_NODE
) {
1497 * global hstate attribute
1499 if (!(obey_mempolicy
&&
1500 init_nodemask_of_mempolicy(nodes_allowed
))) {
1501 NODEMASK_FREE(nodes_allowed
);
1502 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1504 } else if (nodes_allowed
) {
1506 * per node hstate attribute: adjust count to global,
1507 * but restrict alloc/free to the specified node.
1509 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1510 init_nodemask_of_node(nodes_allowed
, nid
);
1512 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1514 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1516 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1517 NODEMASK_FREE(nodes_allowed
);
1521 NODEMASK_FREE(nodes_allowed
);
1525 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1526 struct kobj_attribute
*attr
, char *buf
)
1528 return nr_hugepages_show_common(kobj
, attr
, buf
);
1531 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1532 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1534 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1536 HSTATE_ATTR(nr_hugepages
);
1541 * hstate attribute for optionally mempolicy-based constraint on persistent
1542 * huge page alloc/free.
1544 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1545 struct kobj_attribute
*attr
, char *buf
)
1547 return nr_hugepages_show_common(kobj
, attr
, buf
);
1550 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1551 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1553 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1555 HSTATE_ATTR(nr_hugepages_mempolicy
);
1559 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1560 struct kobj_attribute
*attr
, char *buf
)
1562 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1563 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1566 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1567 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1570 unsigned long input
;
1571 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1573 if (h
->order
>= MAX_ORDER
)
1576 err
= strict_strtoul(buf
, 10, &input
);
1580 spin_lock(&hugetlb_lock
);
1581 h
->nr_overcommit_huge_pages
= input
;
1582 spin_unlock(&hugetlb_lock
);
1586 HSTATE_ATTR(nr_overcommit_hugepages
);
1588 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1589 struct kobj_attribute
*attr
, char *buf
)
1592 unsigned long free_huge_pages
;
1595 h
= kobj_to_hstate(kobj
, &nid
);
1596 if (nid
== NUMA_NO_NODE
)
1597 free_huge_pages
= h
->free_huge_pages
;
1599 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1601 return sprintf(buf
, "%lu\n", free_huge_pages
);
1603 HSTATE_ATTR_RO(free_hugepages
);
1605 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1606 struct kobj_attribute
*attr
, char *buf
)
1608 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1609 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1611 HSTATE_ATTR_RO(resv_hugepages
);
1613 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1614 struct kobj_attribute
*attr
, char *buf
)
1617 unsigned long surplus_huge_pages
;
1620 h
= kobj_to_hstate(kobj
, &nid
);
1621 if (nid
== NUMA_NO_NODE
)
1622 surplus_huge_pages
= h
->surplus_huge_pages
;
1624 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1626 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1628 HSTATE_ATTR_RO(surplus_hugepages
);
1630 static struct attribute
*hstate_attrs
[] = {
1631 &nr_hugepages_attr
.attr
,
1632 &nr_overcommit_hugepages_attr
.attr
,
1633 &free_hugepages_attr
.attr
,
1634 &resv_hugepages_attr
.attr
,
1635 &surplus_hugepages_attr
.attr
,
1637 &nr_hugepages_mempolicy_attr
.attr
,
1642 static struct attribute_group hstate_attr_group
= {
1643 .attrs
= hstate_attrs
,
1646 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1647 struct kobject
**hstate_kobjs
,
1648 struct attribute_group
*hstate_attr_group
)
1651 int hi
= hstate_index(h
);
1653 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1654 if (!hstate_kobjs
[hi
])
1657 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1659 kobject_put(hstate_kobjs
[hi
]);
1664 static void __init
hugetlb_sysfs_init(void)
1669 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1670 if (!hugepages_kobj
)
1673 for_each_hstate(h
) {
1674 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1675 hstate_kobjs
, &hstate_attr_group
);
1677 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1685 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1686 * with node devices in node_devices[] using a parallel array. The array
1687 * index of a node device or _hstate == node id.
1688 * This is here to avoid any static dependency of the node device driver, in
1689 * the base kernel, on the hugetlb module.
1691 struct node_hstate
{
1692 struct kobject
*hugepages_kobj
;
1693 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1695 struct node_hstate node_hstates
[MAX_NUMNODES
];
1698 * A subset of global hstate attributes for node devices
1700 static struct attribute
*per_node_hstate_attrs
[] = {
1701 &nr_hugepages_attr
.attr
,
1702 &free_hugepages_attr
.attr
,
1703 &surplus_hugepages_attr
.attr
,
1707 static struct attribute_group per_node_hstate_attr_group
= {
1708 .attrs
= per_node_hstate_attrs
,
1712 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1713 * Returns node id via non-NULL nidp.
1715 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1719 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1720 struct node_hstate
*nhs
= &node_hstates
[nid
];
1722 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1723 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1735 * Unregister hstate attributes from a single node device.
1736 * No-op if no hstate attributes attached.
1738 void hugetlb_unregister_node(struct node
*node
)
1741 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1743 if (!nhs
->hugepages_kobj
)
1744 return; /* no hstate attributes */
1746 for_each_hstate(h
) {
1747 int idx
= hstate_index(h
);
1748 if (nhs
->hstate_kobjs
[idx
]) {
1749 kobject_put(nhs
->hstate_kobjs
[idx
]);
1750 nhs
->hstate_kobjs
[idx
] = NULL
;
1754 kobject_put(nhs
->hugepages_kobj
);
1755 nhs
->hugepages_kobj
= NULL
;
1759 * hugetlb module exit: unregister hstate attributes from node devices
1762 static void hugetlb_unregister_all_nodes(void)
1767 * disable node device registrations.
1769 register_hugetlbfs_with_node(NULL
, NULL
);
1772 * remove hstate attributes from any nodes that have them.
1774 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1775 hugetlb_unregister_node(&node_devices
[nid
]);
1779 * Register hstate attributes for a single node device.
1780 * No-op if attributes already registered.
1782 void hugetlb_register_node(struct node
*node
)
1785 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1788 if (nhs
->hugepages_kobj
)
1789 return; /* already allocated */
1791 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1793 if (!nhs
->hugepages_kobj
)
1796 for_each_hstate(h
) {
1797 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1799 &per_node_hstate_attr_group
);
1801 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1803 h
->name
, node
->dev
.id
);
1804 hugetlb_unregister_node(node
);
1811 * hugetlb init time: register hstate attributes for all registered node
1812 * devices of nodes that have memory. All on-line nodes should have
1813 * registered their associated device by this time.
1815 static void hugetlb_register_all_nodes(void)
1819 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1820 struct node
*node
= &node_devices
[nid
];
1821 if (node
->dev
.id
== nid
)
1822 hugetlb_register_node(node
);
1826 * Let the node device driver know we're here so it can
1827 * [un]register hstate attributes on node hotplug.
1829 register_hugetlbfs_with_node(hugetlb_register_node
,
1830 hugetlb_unregister_node
);
1832 #else /* !CONFIG_NUMA */
1834 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1842 static void hugetlb_unregister_all_nodes(void) { }
1844 static void hugetlb_register_all_nodes(void) { }
1848 static void __exit
hugetlb_exit(void)
1852 hugetlb_unregister_all_nodes();
1854 for_each_hstate(h
) {
1855 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1858 kobject_put(hugepages_kobj
);
1860 module_exit(hugetlb_exit
);
1862 static int __init
hugetlb_init(void)
1864 /* Some platform decide whether they support huge pages at boot
1865 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1866 * there is no such support
1868 if (HPAGE_SHIFT
== 0)
1871 if (!size_to_hstate(default_hstate_size
)) {
1872 default_hstate_size
= HPAGE_SIZE
;
1873 if (!size_to_hstate(default_hstate_size
))
1874 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1876 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1877 if (default_hstate_max_huge_pages
)
1878 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1880 hugetlb_init_hstates();
1882 gather_bootmem_prealloc();
1886 hugetlb_sysfs_init();
1888 hugetlb_register_all_nodes();
1892 module_init(hugetlb_init
);
1894 /* Should be called on processing a hugepagesz=... option */
1895 void __init
hugetlb_add_hstate(unsigned order
)
1900 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1901 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1904 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1906 h
= &hstates
[hugetlb_max_hstate
++];
1908 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1909 h
->nr_huge_pages
= 0;
1910 h
->free_huge_pages
= 0;
1911 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1912 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1913 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1914 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1915 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1916 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1917 huge_page_size(h
)/1024);
1922 static int __init
hugetlb_nrpages_setup(char *s
)
1925 static unsigned long *last_mhp
;
1928 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1929 * so this hugepages= parameter goes to the "default hstate".
1931 if (!hugetlb_max_hstate
)
1932 mhp
= &default_hstate_max_huge_pages
;
1934 mhp
= &parsed_hstate
->max_huge_pages
;
1936 if (mhp
== last_mhp
) {
1937 printk(KERN_WARNING
"hugepages= specified twice without "
1938 "interleaving hugepagesz=, ignoring\n");
1942 if (sscanf(s
, "%lu", mhp
) <= 0)
1946 * Global state is always initialized later in hugetlb_init.
1947 * But we need to allocate >= MAX_ORDER hstates here early to still
1948 * use the bootmem allocator.
1950 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1951 hugetlb_hstate_alloc_pages(parsed_hstate
);
1957 __setup("hugepages=", hugetlb_nrpages_setup
);
1959 static int __init
hugetlb_default_setup(char *s
)
1961 default_hstate_size
= memparse(s
, &s
);
1964 __setup("default_hugepagesz=", hugetlb_default_setup
);
1966 static unsigned int cpuset_mems_nr(unsigned int *array
)
1969 unsigned int nr
= 0;
1971 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1977 #ifdef CONFIG_SYSCTL
1978 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1979 struct ctl_table
*table
, int write
,
1980 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1982 struct hstate
*h
= &default_hstate
;
1986 tmp
= h
->max_huge_pages
;
1988 if (write
&& h
->order
>= MAX_ORDER
)
1992 table
->maxlen
= sizeof(unsigned long);
1993 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1998 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
1999 GFP_KERNEL
| __GFP_NORETRY
);
2000 if (!(obey_mempolicy
&&
2001 init_nodemask_of_mempolicy(nodes_allowed
))) {
2002 NODEMASK_FREE(nodes_allowed
);
2003 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
2005 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2007 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
2008 NODEMASK_FREE(nodes_allowed
);
2014 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2015 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2018 return hugetlb_sysctl_handler_common(false, table
, write
,
2019 buffer
, length
, ppos
);
2023 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2024 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2026 return hugetlb_sysctl_handler_common(true, table
, write
,
2027 buffer
, length
, ppos
);
2029 #endif /* CONFIG_NUMA */
2031 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2032 void __user
*buffer
,
2033 size_t *length
, loff_t
*ppos
)
2035 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2036 if (hugepages_treat_as_movable
)
2037 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2039 htlb_alloc_mask
= GFP_HIGHUSER
;
2043 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2044 void __user
*buffer
,
2045 size_t *length
, loff_t
*ppos
)
2047 struct hstate
*h
= &default_hstate
;
2051 tmp
= h
->nr_overcommit_huge_pages
;
2053 if (write
&& h
->order
>= MAX_ORDER
)
2057 table
->maxlen
= sizeof(unsigned long);
2058 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2063 spin_lock(&hugetlb_lock
);
2064 h
->nr_overcommit_huge_pages
= tmp
;
2065 spin_unlock(&hugetlb_lock
);
2071 #endif /* CONFIG_SYSCTL */
2073 void hugetlb_report_meminfo(struct seq_file
*m
)
2075 struct hstate
*h
= &default_hstate
;
2077 "HugePages_Total: %5lu\n"
2078 "HugePages_Free: %5lu\n"
2079 "HugePages_Rsvd: %5lu\n"
2080 "HugePages_Surp: %5lu\n"
2081 "Hugepagesize: %8lu kB\n",
2085 h
->surplus_huge_pages
,
2086 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2089 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2091 struct hstate
*h
= &default_hstate
;
2093 "Node %d HugePages_Total: %5u\n"
2094 "Node %d HugePages_Free: %5u\n"
2095 "Node %d HugePages_Surp: %5u\n",
2096 nid
, h
->nr_huge_pages_node
[nid
],
2097 nid
, h
->free_huge_pages_node
[nid
],
2098 nid
, h
->surplus_huge_pages_node
[nid
]);
2101 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2102 unsigned long hugetlb_total_pages(void)
2104 struct hstate
*h
= &default_hstate
;
2105 return h
->nr_huge_pages
* pages_per_huge_page(h
);
2108 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2112 spin_lock(&hugetlb_lock
);
2114 * When cpuset is configured, it breaks the strict hugetlb page
2115 * reservation as the accounting is done on a global variable. Such
2116 * reservation is completely rubbish in the presence of cpuset because
2117 * the reservation is not checked against page availability for the
2118 * current cpuset. Application can still potentially OOM'ed by kernel
2119 * with lack of free htlb page in cpuset that the task is in.
2120 * Attempt to enforce strict accounting with cpuset is almost
2121 * impossible (or too ugly) because cpuset is too fluid that
2122 * task or memory node can be dynamically moved between cpusets.
2124 * The change of semantics for shared hugetlb mapping with cpuset is
2125 * undesirable. However, in order to preserve some of the semantics,
2126 * we fall back to check against current free page availability as
2127 * a best attempt and hopefully to minimize the impact of changing
2128 * semantics that cpuset has.
2131 if (gather_surplus_pages(h
, delta
) < 0)
2134 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2135 return_unused_surplus_pages(h
, delta
);
2142 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2145 spin_unlock(&hugetlb_lock
);
2149 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2151 struct resv_map
*reservations
= vma_resv_map(vma
);
2154 * This new VMA should share its siblings reservation map if present.
2155 * The VMA will only ever have a valid reservation map pointer where
2156 * it is being copied for another still existing VMA. As that VMA
2157 * has a reference to the reservation map it cannot disappear until
2158 * after this open call completes. It is therefore safe to take a
2159 * new reference here without additional locking.
2162 kref_get(&reservations
->refs
);
2165 static void resv_map_put(struct vm_area_struct
*vma
)
2167 struct resv_map
*reservations
= vma_resv_map(vma
);
2171 kref_put(&reservations
->refs
, resv_map_release
);
2174 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2176 struct hstate
*h
= hstate_vma(vma
);
2177 struct resv_map
*reservations
= vma_resv_map(vma
);
2178 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2179 unsigned long reserve
;
2180 unsigned long start
;
2184 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2185 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2187 reserve
= (end
- start
) -
2188 region_count(&reservations
->regions
, start
, end
);
2193 hugetlb_acct_memory(h
, -reserve
);
2194 hugepage_subpool_put_pages(spool
, reserve
);
2200 * We cannot handle pagefaults against hugetlb pages at all. They cause
2201 * handle_mm_fault() to try to instantiate regular-sized pages in the
2202 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2205 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2211 const struct vm_operations_struct hugetlb_vm_ops
= {
2212 .fault
= hugetlb_vm_op_fault
,
2213 .open
= hugetlb_vm_op_open
,
2214 .close
= hugetlb_vm_op_close
,
2217 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2224 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2226 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2228 entry
= pte_mkyoung(entry
);
2229 entry
= pte_mkhuge(entry
);
2230 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2235 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2236 unsigned long address
, pte_t
*ptep
)
2240 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2241 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2242 update_mmu_cache(vma
, address
, ptep
);
2246 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2247 struct vm_area_struct
*vma
)
2249 pte_t
*src_pte
, *dst_pte
, entry
;
2250 struct page
*ptepage
;
2253 struct hstate
*h
= hstate_vma(vma
);
2254 unsigned long sz
= huge_page_size(h
);
2256 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2258 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2259 src_pte
= huge_pte_offset(src
, addr
);
2262 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2266 /* If the pagetables are shared don't copy or take references */
2267 if (dst_pte
== src_pte
)
2270 spin_lock(&dst
->page_table_lock
);
2271 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2272 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2274 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2275 entry
= huge_ptep_get(src_pte
);
2276 ptepage
= pte_page(entry
);
2278 page_dup_rmap(ptepage
);
2279 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2281 spin_unlock(&src
->page_table_lock
);
2282 spin_unlock(&dst
->page_table_lock
);
2290 static int is_hugetlb_entry_migration(pte_t pte
)
2294 if (huge_pte_none(pte
) || pte_present(pte
))
2296 swp
= pte_to_swp_entry(pte
);
2297 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2303 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2307 if (huge_pte_none(pte
) || pte_present(pte
))
2309 swp
= pte_to_swp_entry(pte
);
2310 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2316 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2317 unsigned long start
, unsigned long end
,
2318 struct page
*ref_page
)
2320 int force_flush
= 0;
2321 struct mm_struct
*mm
= vma
->vm_mm
;
2322 unsigned long address
;
2326 struct hstate
*h
= hstate_vma(vma
);
2327 unsigned long sz
= huge_page_size(h
);
2329 WARN_ON(!is_vm_hugetlb_page(vma
));
2330 BUG_ON(start
& ~huge_page_mask(h
));
2331 BUG_ON(end
& ~huge_page_mask(h
));
2333 tlb_start_vma(tlb
, vma
);
2334 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2336 spin_lock(&mm
->page_table_lock
);
2337 for (address
= start
; address
< end
; address
+= sz
) {
2338 ptep
= huge_pte_offset(mm
, address
);
2342 if (huge_pmd_unshare(mm
, &address
, ptep
))
2345 pte
= huge_ptep_get(ptep
);
2346 if (huge_pte_none(pte
))
2350 * HWPoisoned hugepage is already unmapped and dropped reference
2352 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
)))
2355 page
= pte_page(pte
);
2357 * If a reference page is supplied, it is because a specific
2358 * page is being unmapped, not a range. Ensure the page we
2359 * are about to unmap is the actual page of interest.
2362 if (page
!= ref_page
)
2366 * Mark the VMA as having unmapped its page so that
2367 * future faults in this VMA will fail rather than
2368 * looking like data was lost
2370 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2373 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2374 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2376 set_page_dirty(page
);
2378 page_remove_rmap(page
);
2379 force_flush
= !__tlb_remove_page(tlb
, page
);
2382 /* Bail out after unmapping reference page if supplied */
2386 spin_unlock(&mm
->page_table_lock
);
2388 * mmu_gather ran out of room to batch pages, we break out of
2389 * the PTE lock to avoid doing the potential expensive TLB invalidate
2390 * and page-free while holding it.
2395 if (address
< end
&& !ref_page
)
2398 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2399 tlb_end_vma(tlb
, vma
);
2402 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2403 unsigned long end
, struct page
*ref_page
)
2405 struct mm_struct
*mm
;
2406 struct mmu_gather tlb
;
2410 tlb_gather_mmu(&tlb
, mm
, 0);
2411 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2412 tlb_finish_mmu(&tlb
, start
, end
);
2416 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2417 * mappping it owns the reserve page for. The intention is to unmap the page
2418 * from other VMAs and let the children be SIGKILLed if they are faulting the
2421 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2422 struct page
*page
, unsigned long address
)
2424 struct hstate
*h
= hstate_vma(vma
);
2425 struct vm_area_struct
*iter_vma
;
2426 struct address_space
*mapping
;
2427 struct prio_tree_iter iter
;
2431 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2432 * from page cache lookup which is in HPAGE_SIZE units.
2434 address
= address
& huge_page_mask(h
);
2435 pgoff
= vma_hugecache_offset(h
, vma
, address
);
2436 mapping
= vma
->vm_file
->f_dentry
->d_inode
->i_mapping
;
2439 * Take the mapping lock for the duration of the table walk. As
2440 * this mapping should be shared between all the VMAs,
2441 * __unmap_hugepage_range() is called as the lock is already held
2443 mutex_lock(&mapping
->i_mmap_mutex
);
2444 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2445 /* Do not unmap the current VMA */
2446 if (iter_vma
== vma
)
2450 * Unmap the page from other VMAs without their own reserves.
2451 * They get marked to be SIGKILLed if they fault in these
2452 * areas. This is because a future no-page fault on this VMA
2453 * could insert a zeroed page instead of the data existing
2454 * from the time of fork. This would look like data corruption
2456 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2457 unmap_hugepage_range(iter_vma
, address
,
2458 address
+ huge_page_size(h
), page
);
2460 mutex_unlock(&mapping
->i_mmap_mutex
);
2466 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2467 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2468 * cannot race with other handlers or page migration.
2469 * Keep the pte_same checks anyway to make transition from the mutex easier.
2471 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2472 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2473 struct page
*pagecache_page
)
2475 struct hstate
*h
= hstate_vma(vma
);
2476 struct page
*old_page
, *new_page
;
2478 int outside_reserve
= 0;
2480 old_page
= pte_page(pte
);
2483 /* If no-one else is actually using this page, avoid the copy
2484 * and just make the page writable */
2485 avoidcopy
= (page_mapcount(old_page
) == 1);
2487 if (PageAnon(old_page
))
2488 page_move_anon_rmap(old_page
, vma
, address
);
2489 set_huge_ptep_writable(vma
, address
, ptep
);
2494 * If the process that created a MAP_PRIVATE mapping is about to
2495 * perform a COW due to a shared page count, attempt to satisfy
2496 * the allocation without using the existing reserves. The pagecache
2497 * page is used to determine if the reserve at this address was
2498 * consumed or not. If reserves were used, a partial faulted mapping
2499 * at the time of fork() could consume its reserves on COW instead
2500 * of the full address range.
2502 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2503 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2504 old_page
!= pagecache_page
)
2505 outside_reserve
= 1;
2507 page_cache_get(old_page
);
2509 /* Drop page_table_lock as buddy allocator may be called */
2510 spin_unlock(&mm
->page_table_lock
);
2511 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2513 if (IS_ERR(new_page
)) {
2514 long err
= PTR_ERR(new_page
);
2515 page_cache_release(old_page
);
2518 * If a process owning a MAP_PRIVATE mapping fails to COW,
2519 * it is due to references held by a child and an insufficient
2520 * huge page pool. To guarantee the original mappers
2521 * reliability, unmap the page from child processes. The child
2522 * may get SIGKILLed if it later faults.
2524 if (outside_reserve
) {
2525 BUG_ON(huge_pte_none(pte
));
2526 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2527 BUG_ON(huge_pte_none(pte
));
2528 spin_lock(&mm
->page_table_lock
);
2529 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2530 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2531 goto retry_avoidcopy
;
2533 * race occurs while re-acquiring page_table_lock, and
2541 /* Caller expects lock to be held */
2542 spin_lock(&mm
->page_table_lock
);
2544 return VM_FAULT_OOM
;
2546 return VM_FAULT_SIGBUS
;
2550 * When the original hugepage is shared one, it does not have
2551 * anon_vma prepared.
2553 if (unlikely(anon_vma_prepare(vma
))) {
2554 page_cache_release(new_page
);
2555 page_cache_release(old_page
);
2556 /* Caller expects lock to be held */
2557 spin_lock(&mm
->page_table_lock
);
2558 return VM_FAULT_OOM
;
2561 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2562 pages_per_huge_page(h
));
2563 __SetPageUptodate(new_page
);
2566 * Retake the page_table_lock to check for racing updates
2567 * before the page tables are altered
2569 spin_lock(&mm
->page_table_lock
);
2570 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2571 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2573 mmu_notifier_invalidate_range_start(mm
,
2574 address
& huge_page_mask(h
),
2575 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2576 huge_ptep_clear_flush(vma
, address
, ptep
);
2577 set_huge_pte_at(mm
, address
, ptep
,
2578 make_huge_pte(vma
, new_page
, 1));
2579 page_remove_rmap(old_page
);
2580 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2581 /* Make the old page be freed below */
2582 new_page
= old_page
;
2583 mmu_notifier_invalidate_range_end(mm
,
2584 address
& huge_page_mask(h
),
2585 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2587 page_cache_release(new_page
);
2588 page_cache_release(old_page
);
2592 /* Return the pagecache page at a given address within a VMA */
2593 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2594 struct vm_area_struct
*vma
, unsigned long address
)
2596 struct address_space
*mapping
;
2599 mapping
= vma
->vm_file
->f_mapping
;
2600 idx
= vma_hugecache_offset(h
, vma
, address
);
2602 return find_lock_page(mapping
, idx
);
2606 * Return whether there is a pagecache page to back given address within VMA.
2607 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2609 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2610 struct vm_area_struct
*vma
, unsigned long address
)
2612 struct address_space
*mapping
;
2616 mapping
= vma
->vm_file
->f_mapping
;
2617 idx
= vma_hugecache_offset(h
, vma
, address
);
2619 page
= find_get_page(mapping
, idx
);
2622 return page
!= NULL
;
2625 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2626 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2628 struct hstate
*h
= hstate_vma(vma
);
2629 int ret
= VM_FAULT_SIGBUS
;
2634 struct address_space
*mapping
;
2638 * Currently, we are forced to kill the process in the event the
2639 * original mapper has unmapped pages from the child due to a failed
2640 * COW. Warn that such a situation has occurred as it may not be obvious
2642 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2644 "PID %d killed due to inadequate hugepage pool\n",
2649 mapping
= vma
->vm_file
->f_mapping
;
2650 idx
= vma_hugecache_offset(h
, vma
, address
);
2653 * Use page lock to guard against racing truncation
2654 * before we get page_table_lock.
2657 page
= find_lock_page(mapping
, idx
);
2659 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2662 page
= alloc_huge_page(vma
, address
, 0);
2664 ret
= PTR_ERR(page
);
2668 ret
= VM_FAULT_SIGBUS
;
2671 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2672 __SetPageUptodate(page
);
2674 if (vma
->vm_flags
& VM_MAYSHARE
) {
2676 struct inode
*inode
= mapping
->host
;
2678 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2686 spin_lock(&inode
->i_lock
);
2687 inode
->i_blocks
+= blocks_per_huge_page(h
);
2688 spin_unlock(&inode
->i_lock
);
2691 if (unlikely(anon_vma_prepare(vma
))) {
2693 goto backout_unlocked
;
2699 * If memory error occurs between mmap() and fault, some process
2700 * don't have hwpoisoned swap entry for errored virtual address.
2701 * So we need to block hugepage fault by PG_hwpoison bit check.
2703 if (unlikely(PageHWPoison(page
))) {
2704 ret
= VM_FAULT_HWPOISON
|
2705 VM_FAULT_SET_HINDEX(hstate_index(h
));
2706 goto backout_unlocked
;
2711 * If we are going to COW a private mapping later, we examine the
2712 * pending reservations for this page now. This will ensure that
2713 * any allocations necessary to record that reservation occur outside
2716 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2717 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2719 goto backout_unlocked
;
2722 spin_lock(&mm
->page_table_lock
);
2723 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2728 if (!huge_pte_none(huge_ptep_get(ptep
)))
2732 hugepage_add_new_anon_rmap(page
, vma
, address
);
2734 page_dup_rmap(page
);
2735 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2736 && (vma
->vm_flags
& VM_SHARED
)));
2737 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2739 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2740 /* Optimization, do the COW without a second fault */
2741 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2744 spin_unlock(&mm
->page_table_lock
);
2750 spin_unlock(&mm
->page_table_lock
);
2757 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2758 unsigned long address
, unsigned int flags
)
2763 struct page
*page
= NULL
;
2764 struct page
*pagecache_page
= NULL
;
2765 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2766 struct hstate
*h
= hstate_vma(vma
);
2768 address
&= huge_page_mask(h
);
2770 ptep
= huge_pte_offset(mm
, address
);
2772 entry
= huge_ptep_get(ptep
);
2773 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2774 migration_entry_wait(mm
, (pmd_t
*)ptep
, address
);
2776 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2777 return VM_FAULT_HWPOISON_LARGE
|
2778 VM_FAULT_SET_HINDEX(hstate_index(h
));
2781 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2783 return VM_FAULT_OOM
;
2786 * Serialize hugepage allocation and instantiation, so that we don't
2787 * get spurious allocation failures if two CPUs race to instantiate
2788 * the same page in the page cache.
2790 mutex_lock(&hugetlb_instantiation_mutex
);
2791 entry
= huge_ptep_get(ptep
);
2792 if (huge_pte_none(entry
)) {
2793 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2800 * If we are going to COW the mapping later, we examine the pending
2801 * reservations for this page now. This will ensure that any
2802 * allocations necessary to record that reservation occur outside the
2803 * spinlock. For private mappings, we also lookup the pagecache
2804 * page now as it is used to determine if a reservation has been
2807 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2808 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2813 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2814 pagecache_page
= hugetlbfs_pagecache_page(h
,
2819 * hugetlb_cow() requires page locks of pte_page(entry) and
2820 * pagecache_page, so here we need take the former one
2821 * when page != pagecache_page or !pagecache_page.
2822 * Note that locking order is always pagecache_page -> page,
2823 * so no worry about deadlock.
2825 page
= pte_page(entry
);
2827 if (page
!= pagecache_page
)
2830 spin_lock(&mm
->page_table_lock
);
2831 /* Check for a racing update before calling hugetlb_cow */
2832 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2833 goto out_page_table_lock
;
2836 if (flags
& FAULT_FLAG_WRITE
) {
2837 if (!pte_write(entry
)) {
2838 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2840 goto out_page_table_lock
;
2842 entry
= pte_mkdirty(entry
);
2844 entry
= pte_mkyoung(entry
);
2845 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2846 flags
& FAULT_FLAG_WRITE
))
2847 update_mmu_cache(vma
, address
, ptep
);
2849 out_page_table_lock
:
2850 spin_unlock(&mm
->page_table_lock
);
2852 if (pagecache_page
) {
2853 unlock_page(pagecache_page
);
2854 put_page(pagecache_page
);
2856 if (page
!= pagecache_page
)
2861 mutex_unlock(&hugetlb_instantiation_mutex
);
2866 /* Can be overriden by architectures */
2867 __attribute__((weak
)) struct page
*
2868 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2869 pud_t
*pud
, int write
)
2875 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2876 struct page
**pages
, struct vm_area_struct
**vmas
,
2877 unsigned long *position
, int *length
, int i
,
2880 unsigned long pfn_offset
;
2881 unsigned long vaddr
= *position
;
2882 int remainder
= *length
;
2883 struct hstate
*h
= hstate_vma(vma
);
2885 spin_lock(&mm
->page_table_lock
);
2886 while (vaddr
< vma
->vm_end
&& remainder
) {
2892 * Some archs (sparc64, sh*) have multiple pte_ts to
2893 * each hugepage. We have to make sure we get the
2894 * first, for the page indexing below to work.
2896 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2897 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2900 * When coredumping, it suits get_dump_page if we just return
2901 * an error where there's an empty slot with no huge pagecache
2902 * to back it. This way, we avoid allocating a hugepage, and
2903 * the sparse dumpfile avoids allocating disk blocks, but its
2904 * huge holes still show up with zeroes where they need to be.
2906 if (absent
&& (flags
& FOLL_DUMP
) &&
2907 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2913 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2916 spin_unlock(&mm
->page_table_lock
);
2917 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2918 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2919 spin_lock(&mm
->page_table_lock
);
2920 if (!(ret
& VM_FAULT_ERROR
))
2927 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2928 page
= pte_page(huge_ptep_get(pte
));
2931 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2942 if (vaddr
< vma
->vm_end
&& remainder
&&
2943 pfn_offset
< pages_per_huge_page(h
)) {
2945 * We use pfn_offset to avoid touching the pageframes
2946 * of this compound page.
2951 spin_unlock(&mm
->page_table_lock
);
2952 *length
= remainder
;
2955 return i
? i
: -EFAULT
;
2958 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2959 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2961 struct mm_struct
*mm
= vma
->vm_mm
;
2962 unsigned long start
= address
;
2965 struct hstate
*h
= hstate_vma(vma
);
2967 BUG_ON(address
>= end
);
2968 flush_cache_range(vma
, address
, end
);
2970 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2971 spin_lock(&mm
->page_table_lock
);
2972 for (; address
< end
; address
+= huge_page_size(h
)) {
2973 ptep
= huge_pte_offset(mm
, address
);
2976 if (huge_pmd_unshare(mm
, &address
, ptep
))
2978 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2979 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2980 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2981 set_huge_pte_at(mm
, address
, ptep
, pte
);
2984 spin_unlock(&mm
->page_table_lock
);
2985 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2987 flush_tlb_range(vma
, start
, end
);
2990 int hugetlb_reserve_pages(struct inode
*inode
,
2992 struct vm_area_struct
*vma
,
2993 vm_flags_t vm_flags
)
2996 struct hstate
*h
= hstate_inode(inode
);
2997 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3000 * Only apply hugepage reservation if asked. At fault time, an
3001 * attempt will be made for VM_NORESERVE to allocate a page
3002 * without using reserves
3004 if (vm_flags
& VM_NORESERVE
)
3008 * Shared mappings base their reservation on the number of pages that
3009 * are already allocated on behalf of the file. Private mappings need
3010 * to reserve the full area even if read-only as mprotect() may be
3011 * called to make the mapping read-write. Assume !vma is a shm mapping
3013 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3014 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3016 struct resv_map
*resv_map
= resv_map_alloc();
3022 set_vma_resv_map(vma
, resv_map
);
3023 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3031 /* There must be enough pages in the subpool for the mapping */
3032 if (hugepage_subpool_get_pages(spool
, chg
)) {
3038 * Check enough hugepages are available for the reservation.
3039 * Hand the pages back to the subpool if there are not
3041 ret
= hugetlb_acct_memory(h
, chg
);
3043 hugepage_subpool_put_pages(spool
, chg
);
3048 * Account for the reservations made. Shared mappings record regions
3049 * that have reservations as they are shared by multiple VMAs.
3050 * When the last VMA disappears, the region map says how much
3051 * the reservation was and the page cache tells how much of
3052 * the reservation was consumed. Private mappings are per-VMA and
3053 * only the consumed reservations are tracked. When the VMA
3054 * disappears, the original reservation is the VMA size and the
3055 * consumed reservations are stored in the map. Hence, nothing
3056 * else has to be done for private mappings here
3058 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3059 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3067 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3069 struct hstate
*h
= hstate_inode(inode
);
3070 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3071 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3073 spin_lock(&inode
->i_lock
);
3074 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3075 spin_unlock(&inode
->i_lock
);
3077 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3078 hugetlb_acct_memory(h
, -(chg
- freed
));
3081 #ifdef CONFIG_MEMORY_FAILURE
3083 /* Should be called in hugetlb_lock */
3084 static int is_hugepage_on_freelist(struct page
*hpage
)
3088 struct hstate
*h
= page_hstate(hpage
);
3089 int nid
= page_to_nid(hpage
);
3091 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3098 * This function is called from memory failure code.
3099 * Assume the caller holds page lock of the head page.
3101 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3103 struct hstate
*h
= page_hstate(hpage
);
3104 int nid
= page_to_nid(hpage
);
3107 spin_lock(&hugetlb_lock
);
3108 if (is_hugepage_on_freelist(hpage
)) {
3109 list_del(&hpage
->lru
);
3110 set_page_refcounted(hpage
);
3111 h
->free_huge_pages
--;
3112 h
->free_huge_pages_node
[nid
]--;
3115 spin_unlock(&hugetlb_lock
);