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>
24 #include <asm/pgtable.h>
27 #include <linux/hugetlb.h>
28 #include <linux/node.h>
31 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
32 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
33 unsigned long hugepages_treat_as_movable
;
35 static int max_hstate
;
36 unsigned int default_hstate_idx
;
37 struct hstate hstates
[HUGE_MAX_HSTATE
];
39 __initdata
LIST_HEAD(huge_boot_pages
);
41 /* for command line parsing */
42 static struct hstate
* __initdata parsed_hstate
;
43 static unsigned long __initdata default_hstate_max_huge_pages
;
44 static unsigned long __initdata default_hstate_size
;
46 #define for_each_hstate(h) \
47 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
50 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
52 static DEFINE_SPINLOCK(hugetlb_lock
);
55 * Region tracking -- allows tracking of reservations and instantiated pages
56 * across the pages in a mapping.
58 * The region data structures are protected by a combination of the mmap_sem
59 * and the hugetlb_instantion_mutex. To access or modify a region the caller
60 * must either hold the mmap_sem for write, or the mmap_sem for read and
61 * the hugetlb_instantiation mutex:
63 * down_write(&mm->mmap_sem);
65 * down_read(&mm->mmap_sem);
66 * mutex_lock(&hugetlb_instantiation_mutex);
69 struct list_head link
;
74 static long region_add(struct list_head
*head
, long f
, long t
)
76 struct file_region
*rg
, *nrg
, *trg
;
78 /* Locate the region we are either in or before. */
79 list_for_each_entry(rg
, head
, link
)
83 /* Round our left edge to the current segment if it encloses us. */
87 /* Check for and consume any regions we now overlap with. */
89 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
90 if (&rg
->link
== head
)
95 /* If this area reaches higher then extend our area to
96 * include it completely. If this is not the first area
97 * which we intend to reuse, free it. */
110 static long region_chg(struct list_head
*head
, long f
, long t
)
112 struct file_region
*rg
, *nrg
;
115 /* Locate the region we are before or in. */
116 list_for_each_entry(rg
, head
, link
)
120 /* If we are below the current region then a new region is required.
121 * Subtle, allocate a new region at the position but make it zero
122 * size such that we can guarantee to record the reservation. */
123 if (&rg
->link
== head
|| t
< rg
->from
) {
124 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
129 INIT_LIST_HEAD(&nrg
->link
);
130 list_add(&nrg
->link
, rg
->link
.prev
);
135 /* Round our left edge to the current segment if it encloses us. */
140 /* Check for and consume any regions we now overlap with. */
141 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
142 if (&rg
->link
== head
)
147 /* We overlap with this area, if it extends futher than
148 * us then we must extend ourselves. Account for its
149 * existing reservation. */
154 chg
-= rg
->to
- rg
->from
;
159 static long region_truncate(struct list_head
*head
, long end
)
161 struct file_region
*rg
, *trg
;
164 /* Locate the region we are either in or before. */
165 list_for_each_entry(rg
, head
, link
)
168 if (&rg
->link
== head
)
171 /* If we are in the middle of a region then adjust it. */
172 if (end
> rg
->from
) {
175 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
178 /* Drop any remaining regions. */
179 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
180 if (&rg
->link
== head
)
182 chg
+= rg
->to
- rg
->from
;
189 static long region_count(struct list_head
*head
, long f
, long t
)
191 struct file_region
*rg
;
194 /* Locate each segment we overlap with, and count that overlap. */
195 list_for_each_entry(rg
, head
, link
) {
204 seg_from
= max(rg
->from
, f
);
205 seg_to
= min(rg
->to
, t
);
207 chg
+= seg_to
- seg_from
;
214 * Convert the address within this vma to the page offset within
215 * the mapping, in pagecache page units; huge pages here.
217 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
218 struct vm_area_struct
*vma
, unsigned long address
)
220 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
221 (vma
->vm_pgoff
>> huge_page_order(h
));
224 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
225 unsigned long address
)
227 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
231 * Return the size of the pages allocated when backing a VMA. In the majority
232 * cases this will be same size as used by the page table entries.
234 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
236 struct hstate
*hstate
;
238 if (!is_vm_hugetlb_page(vma
))
241 hstate
= hstate_vma(vma
);
243 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
245 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
248 * Return the page size being used by the MMU to back a VMA. In the majority
249 * of cases, the page size used by the kernel matches the MMU size. On
250 * architectures where it differs, an architecture-specific version of this
251 * function is required.
253 #ifndef vma_mmu_pagesize
254 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
256 return vma_kernel_pagesize(vma
);
261 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
262 * bits of the reservation map pointer, which are always clear due to
265 #define HPAGE_RESV_OWNER (1UL << 0)
266 #define HPAGE_RESV_UNMAPPED (1UL << 1)
267 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
270 * These helpers are used to track how many pages are reserved for
271 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
272 * is guaranteed to have their future faults succeed.
274 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
275 * the reserve counters are updated with the hugetlb_lock held. It is safe
276 * to reset the VMA at fork() time as it is not in use yet and there is no
277 * chance of the global counters getting corrupted as a result of the values.
279 * The private mapping reservation is represented in a subtly different
280 * manner to a shared mapping. A shared mapping has a region map associated
281 * with the underlying file, this region map represents the backing file
282 * pages which have ever had a reservation assigned which this persists even
283 * after the page is instantiated. A private mapping has a region map
284 * associated with the original mmap which is attached to all VMAs which
285 * reference it, this region map represents those offsets which have consumed
286 * reservation ie. where pages have been instantiated.
288 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
290 return (unsigned long)vma
->vm_private_data
;
293 static void set_vma_private_data(struct vm_area_struct
*vma
,
296 vma
->vm_private_data
= (void *)value
;
301 struct list_head regions
;
304 static struct resv_map
*resv_map_alloc(void)
306 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
310 kref_init(&resv_map
->refs
);
311 INIT_LIST_HEAD(&resv_map
->regions
);
316 static void resv_map_release(struct kref
*ref
)
318 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
320 /* Clear out any active regions before we release the map. */
321 region_truncate(&resv_map
->regions
, 0);
325 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
327 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
328 if (!(vma
->vm_flags
& VM_MAYSHARE
))
329 return (struct resv_map
*)(get_vma_private_data(vma
) &
334 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
336 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
337 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
339 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
340 HPAGE_RESV_MASK
) | (unsigned long)map
);
343 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
345 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
346 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
348 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
351 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
353 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
355 return (get_vma_private_data(vma
) & flag
) != 0;
358 /* Decrement the reserved pages in the hugepage pool by one */
359 static void decrement_hugepage_resv_vma(struct hstate
*h
,
360 struct vm_area_struct
*vma
)
362 if (vma
->vm_flags
& VM_NORESERVE
)
365 if (vma
->vm_flags
& VM_MAYSHARE
) {
366 /* Shared mappings always use reserves */
367 h
->resv_huge_pages
--;
368 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
370 * Only the process that called mmap() has reserves for
373 h
->resv_huge_pages
--;
377 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
378 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
380 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
381 if (!(vma
->vm_flags
& VM_MAYSHARE
))
382 vma
->vm_private_data
= (void *)0;
385 /* Returns true if the VMA has associated reserve pages */
386 static int vma_has_reserves(struct vm_area_struct
*vma
)
388 if (vma
->vm_flags
& VM_MAYSHARE
)
390 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
395 static void clear_gigantic_page(struct page
*page
,
396 unsigned long addr
, unsigned long sz
)
399 struct page
*p
= page
;
402 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++, p
= mem_map_next(p
, page
, i
)) {
404 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
407 static void clear_huge_page(struct page
*page
,
408 unsigned long addr
, unsigned long sz
)
412 if (unlikely(sz
/PAGE_SIZE
> MAX_ORDER_NR_PAGES
)) {
413 clear_gigantic_page(page
, addr
, sz
);
418 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
420 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
424 static void copy_gigantic_page(struct page
*dst
, struct page
*src
,
425 unsigned long addr
, struct vm_area_struct
*vma
)
428 struct hstate
*h
= hstate_vma(vma
);
429 struct page
*dst_base
= dst
;
430 struct page
*src_base
= src
;
432 for (i
= 0; i
< pages_per_huge_page(h
); ) {
434 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
437 dst
= mem_map_next(dst
, dst_base
, i
);
438 src
= mem_map_next(src
, src_base
, i
);
441 static void copy_huge_page(struct page
*dst
, struct page
*src
,
442 unsigned long addr
, struct vm_area_struct
*vma
)
445 struct hstate
*h
= hstate_vma(vma
);
447 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
448 copy_gigantic_page(dst
, src
, addr
, vma
);
453 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
455 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
459 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
461 int nid
= page_to_nid(page
);
462 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
463 h
->free_huge_pages
++;
464 h
->free_huge_pages_node
[nid
]++;
467 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
468 struct vm_area_struct
*vma
,
469 unsigned long address
, int avoid_reserve
)
472 struct page
*page
= NULL
;
473 struct mempolicy
*mpol
;
474 nodemask_t
*nodemask
;
475 struct zonelist
*zonelist
;
480 zonelist
= huge_zonelist(vma
, address
,
481 htlb_alloc_mask
, &mpol
, &nodemask
);
483 * A child process with MAP_PRIVATE mappings created by their parent
484 * have no page reserves. This check ensures that reservations are
485 * not "stolen". The child may still get SIGKILLed
487 if (!vma_has_reserves(vma
) &&
488 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
491 /* If reserves cannot be used, ensure enough pages are in the pool */
492 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
495 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
496 MAX_NR_ZONES
- 1, nodemask
) {
497 nid
= zone_to_nid(zone
);
498 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
499 !list_empty(&h
->hugepage_freelists
[nid
])) {
500 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
502 list_del(&page
->lru
);
503 h
->free_huge_pages
--;
504 h
->free_huge_pages_node
[nid
]--;
507 decrement_hugepage_resv_vma(h
, vma
);
518 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
522 VM_BUG_ON(h
->order
>= MAX_ORDER
);
525 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
526 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
527 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
528 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
529 1 << PG_private
| 1<< PG_writeback
);
531 set_compound_page_dtor(page
, NULL
);
532 set_page_refcounted(page
);
533 arch_release_hugepage(page
);
534 __free_pages(page
, huge_page_order(h
));
537 struct hstate
*size_to_hstate(unsigned long size
)
542 if (huge_page_size(h
) == size
)
548 static void free_huge_page(struct page
*page
)
551 * Can't pass hstate in here because it is called from the
552 * compound page destructor.
554 struct hstate
*h
= page_hstate(page
);
555 int nid
= page_to_nid(page
);
556 struct address_space
*mapping
;
558 mapping
= (struct address_space
*) page_private(page
);
559 set_page_private(page
, 0);
560 page
->mapping
= NULL
;
561 BUG_ON(page_count(page
));
562 BUG_ON(page_mapcount(page
));
563 INIT_LIST_HEAD(&page
->lru
);
565 spin_lock(&hugetlb_lock
);
566 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
567 update_and_free_page(h
, page
);
568 h
->surplus_huge_pages
--;
569 h
->surplus_huge_pages_node
[nid
]--;
571 enqueue_huge_page(h
, page
);
573 spin_unlock(&hugetlb_lock
);
575 hugetlb_put_quota(mapping
, 1);
578 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
580 set_compound_page_dtor(page
, free_huge_page
);
581 spin_lock(&hugetlb_lock
);
583 h
->nr_huge_pages_node
[nid
]++;
584 spin_unlock(&hugetlb_lock
);
585 put_page(page
); /* free it into the hugepage allocator */
588 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
591 int nr_pages
= 1 << order
;
592 struct page
*p
= page
+ 1;
594 /* we rely on prep_new_huge_page to set the destructor */
595 set_compound_order(page
, order
);
597 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
599 p
->first_page
= page
;
603 int PageHuge(struct page
*page
)
605 compound_page_dtor
*dtor
;
607 if (!PageCompound(page
))
610 page
= compound_head(page
);
611 dtor
= get_compound_page_dtor(page
);
613 return dtor
== free_huge_page
;
616 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
620 if (h
->order
>= MAX_ORDER
)
623 page
= alloc_pages_exact_node(nid
,
624 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
625 __GFP_REPEAT
|__GFP_NOWARN
,
628 if (arch_prepare_hugepage(page
)) {
629 __free_pages(page
, huge_page_order(h
));
632 prep_new_huge_page(h
, page
, nid
);
639 * common helper functions for hstate_next_node_to_{alloc|free}.
640 * We may have allocated or freed a huge page based on a different
641 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
642 * be outside of *nodes_allowed. Ensure that we use an allowed
643 * node for alloc or free.
645 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
647 nid
= next_node(nid
, *nodes_allowed
);
648 if (nid
== MAX_NUMNODES
)
649 nid
= first_node(*nodes_allowed
);
650 VM_BUG_ON(nid
>= MAX_NUMNODES
);
655 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
657 if (!node_isset(nid
, *nodes_allowed
))
658 nid
= next_node_allowed(nid
, nodes_allowed
);
663 * returns the previously saved node ["this node"] from which to
664 * allocate a persistent huge page for the pool and advance the
665 * next node from which to allocate, handling wrap at end of node
668 static int hstate_next_node_to_alloc(struct hstate
*h
,
669 nodemask_t
*nodes_allowed
)
673 VM_BUG_ON(!nodes_allowed
);
675 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
676 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
681 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
688 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
689 next_nid
= start_nid
;
692 page
= alloc_fresh_huge_page_node(h
, next_nid
);
697 next_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
698 } while (next_nid
!= start_nid
);
701 count_vm_event(HTLB_BUDDY_PGALLOC
);
703 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
709 * helper for free_pool_huge_page() - return the previously saved
710 * node ["this node"] from which to free a huge page. Advance the
711 * next node id whether or not we find a free huge page to free so
712 * that the next attempt to free addresses the next node.
714 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
718 VM_BUG_ON(!nodes_allowed
);
720 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
721 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
727 * Free huge page from pool from next node to free.
728 * Attempt to keep persistent huge pages more or less
729 * balanced over allowed nodes.
730 * Called with hugetlb_lock locked.
732 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
739 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
740 next_nid
= start_nid
;
744 * If we're returning unused surplus pages, only examine
745 * nodes with surplus pages.
747 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
748 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
750 list_entry(h
->hugepage_freelists
[next_nid
].next
,
752 list_del(&page
->lru
);
753 h
->free_huge_pages
--;
754 h
->free_huge_pages_node
[next_nid
]--;
756 h
->surplus_huge_pages
--;
757 h
->surplus_huge_pages_node
[next_nid
]--;
759 update_and_free_page(h
, page
);
763 next_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
764 } while (next_nid
!= start_nid
);
769 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
770 struct vm_area_struct
*vma
, unsigned long address
)
775 if (h
->order
>= MAX_ORDER
)
779 * Assume we will successfully allocate the surplus page to
780 * prevent racing processes from causing the surplus to exceed
783 * This however introduces a different race, where a process B
784 * tries to grow the static hugepage pool while alloc_pages() is
785 * called by process A. B will only examine the per-node
786 * counters in determining if surplus huge pages can be
787 * converted to normal huge pages in adjust_pool_surplus(). A
788 * won't be able to increment the per-node counter, until the
789 * lock is dropped by B, but B doesn't drop hugetlb_lock until
790 * no more huge pages can be converted from surplus to normal
791 * state (and doesn't try to convert again). Thus, we have a
792 * case where a surplus huge page exists, the pool is grown, and
793 * the surplus huge page still exists after, even though it
794 * should just have been converted to a normal huge page. This
795 * does not leak memory, though, as the hugepage will be freed
796 * once it is out of use. It also does not allow the counters to
797 * go out of whack in adjust_pool_surplus() as we don't modify
798 * the node values until we've gotten the hugepage and only the
799 * per-node value is checked there.
801 spin_lock(&hugetlb_lock
);
802 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
803 spin_unlock(&hugetlb_lock
);
807 h
->surplus_huge_pages
++;
809 spin_unlock(&hugetlb_lock
);
811 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
812 __GFP_REPEAT
|__GFP_NOWARN
,
815 if (page
&& arch_prepare_hugepage(page
)) {
816 __free_pages(page
, huge_page_order(h
));
820 spin_lock(&hugetlb_lock
);
823 * This page is now managed by the hugetlb allocator and has
824 * no users -- drop the buddy allocator's reference.
826 put_page_testzero(page
);
827 VM_BUG_ON(page_count(page
));
828 nid
= page_to_nid(page
);
829 set_compound_page_dtor(page
, free_huge_page
);
831 * We incremented the global counters already
833 h
->nr_huge_pages_node
[nid
]++;
834 h
->surplus_huge_pages_node
[nid
]++;
835 __count_vm_event(HTLB_BUDDY_PGALLOC
);
838 h
->surplus_huge_pages
--;
839 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
841 spin_unlock(&hugetlb_lock
);
847 * Increase the hugetlb pool such that it can accomodate a reservation
850 static int gather_surplus_pages(struct hstate
*h
, int delta
)
852 struct list_head surplus_list
;
853 struct page
*page
, *tmp
;
855 int needed
, allocated
;
857 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
859 h
->resv_huge_pages
+= delta
;
864 INIT_LIST_HEAD(&surplus_list
);
868 spin_unlock(&hugetlb_lock
);
869 for (i
= 0; i
< needed
; i
++) {
870 page
= alloc_buddy_huge_page(h
, NULL
, 0);
873 * We were not able to allocate enough pages to
874 * satisfy the entire reservation so we free what
875 * we've allocated so far.
877 spin_lock(&hugetlb_lock
);
882 list_add(&page
->lru
, &surplus_list
);
887 * After retaking hugetlb_lock, we need to recalculate 'needed'
888 * because either resv_huge_pages or free_huge_pages may have changed.
890 spin_lock(&hugetlb_lock
);
891 needed
= (h
->resv_huge_pages
+ delta
) -
892 (h
->free_huge_pages
+ allocated
);
897 * The surplus_list now contains _at_least_ the number of extra pages
898 * needed to accomodate the reservation. Add the appropriate number
899 * of pages to the hugetlb pool and free the extras back to the buddy
900 * allocator. Commit the entire reservation here to prevent another
901 * process from stealing the pages as they are added to the pool but
902 * before they are reserved.
905 h
->resv_huge_pages
+= delta
;
908 /* Free the needed pages to the hugetlb pool */
909 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
912 list_del(&page
->lru
);
913 enqueue_huge_page(h
, page
);
916 /* Free unnecessary surplus pages to the buddy allocator */
917 if (!list_empty(&surplus_list
)) {
918 spin_unlock(&hugetlb_lock
);
919 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
920 list_del(&page
->lru
);
922 * The page has a reference count of zero already, so
923 * call free_huge_page directly instead of using
924 * put_page. This must be done with hugetlb_lock
925 * unlocked which is safe because free_huge_page takes
926 * hugetlb_lock before deciding how to free the page.
928 free_huge_page(page
);
930 spin_lock(&hugetlb_lock
);
937 * When releasing a hugetlb pool reservation, any surplus pages that were
938 * allocated to satisfy the reservation must be explicitly freed if they were
940 * Called with hugetlb_lock held.
942 static void return_unused_surplus_pages(struct hstate
*h
,
943 unsigned long unused_resv_pages
)
945 unsigned long nr_pages
;
947 /* Uncommit the reservation */
948 h
->resv_huge_pages
-= unused_resv_pages
;
950 /* Cannot return gigantic pages currently */
951 if (h
->order
>= MAX_ORDER
)
954 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
957 * We want to release as many surplus pages as possible, spread
958 * evenly across all nodes with memory. Iterate across these nodes
959 * until we can no longer free unreserved surplus pages. This occurs
960 * when the nodes with surplus pages have no free pages.
961 * free_pool_huge_page() will balance the the freed pages across the
962 * on-line nodes with memory and will handle the hstate accounting.
965 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
971 * Determine if the huge page at addr within the vma has an associated
972 * reservation. Where it does not we will need to logically increase
973 * reservation and actually increase quota before an allocation can occur.
974 * Where any new reservation would be required the reservation change is
975 * prepared, but not committed. Once the page has been quota'd allocated
976 * an instantiated the change should be committed via vma_commit_reservation.
977 * No action is required on failure.
979 static long vma_needs_reservation(struct hstate
*h
,
980 struct vm_area_struct
*vma
, unsigned long addr
)
982 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
983 struct inode
*inode
= mapping
->host
;
985 if (vma
->vm_flags
& VM_MAYSHARE
) {
986 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
987 return region_chg(&inode
->i_mapping
->private_list
,
990 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
995 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
996 struct resv_map
*reservations
= vma_resv_map(vma
);
998 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1004 static void vma_commit_reservation(struct hstate
*h
,
1005 struct vm_area_struct
*vma
, unsigned long addr
)
1007 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1008 struct inode
*inode
= mapping
->host
;
1010 if (vma
->vm_flags
& VM_MAYSHARE
) {
1011 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1012 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1014 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1015 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1016 struct resv_map
*reservations
= vma_resv_map(vma
);
1018 /* Mark this page used in the map. */
1019 region_add(&reservations
->regions
, idx
, idx
+ 1);
1023 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1024 unsigned long addr
, int avoid_reserve
)
1026 struct hstate
*h
= hstate_vma(vma
);
1028 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1029 struct inode
*inode
= mapping
->host
;
1033 * Processes that did not create the mapping will have no reserves and
1034 * will not have accounted against quota. Check that the quota can be
1035 * made before satisfying the allocation
1036 * MAP_NORESERVE mappings may also need pages and quota allocated
1037 * if no reserve mapping overlaps.
1039 chg
= vma_needs_reservation(h
, vma
, addr
);
1041 return ERR_PTR(chg
);
1043 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1044 return ERR_PTR(-ENOSPC
);
1046 spin_lock(&hugetlb_lock
);
1047 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1048 spin_unlock(&hugetlb_lock
);
1051 page
= alloc_buddy_huge_page(h
, vma
, addr
);
1053 hugetlb_put_quota(inode
->i_mapping
, chg
);
1054 return ERR_PTR(-VM_FAULT_SIGBUS
);
1058 set_page_refcounted(page
);
1059 set_page_private(page
, (unsigned long) mapping
);
1061 vma_commit_reservation(h
, vma
, addr
);
1066 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1068 struct huge_bootmem_page
*m
;
1069 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1074 addr
= __alloc_bootmem_node_nopanic(
1075 NODE_DATA(hstate_next_node_to_alloc(h
,
1076 &node_states
[N_HIGH_MEMORY
])),
1077 huge_page_size(h
), huge_page_size(h
), 0);
1081 * Use the beginning of the huge page to store the
1082 * huge_bootmem_page struct (until gather_bootmem
1083 * puts them into the mem_map).
1093 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1094 /* Put them into a private list first because mem_map is not up yet */
1095 list_add(&m
->list
, &huge_boot_pages
);
1100 static void prep_compound_huge_page(struct page
*page
, int order
)
1102 if (unlikely(order
> (MAX_ORDER
- 1)))
1103 prep_compound_gigantic_page(page
, order
);
1105 prep_compound_page(page
, order
);
1108 /* Put bootmem huge pages into the standard lists after mem_map is up */
1109 static void __init
gather_bootmem_prealloc(void)
1111 struct huge_bootmem_page
*m
;
1113 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1114 struct page
*page
= virt_to_page(m
);
1115 struct hstate
*h
= m
->hstate
;
1116 __ClearPageReserved(page
);
1117 WARN_ON(page_count(page
) != 1);
1118 prep_compound_huge_page(page
, h
->order
);
1119 prep_new_huge_page(h
, page
, page_to_nid(page
));
1123 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1127 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1128 if (h
->order
>= MAX_ORDER
) {
1129 if (!alloc_bootmem_huge_page(h
))
1131 } else if (!alloc_fresh_huge_page(h
,
1132 &node_states
[N_HIGH_MEMORY
]))
1135 h
->max_huge_pages
= i
;
1138 static void __init
hugetlb_init_hstates(void)
1142 for_each_hstate(h
) {
1143 /* oversize hugepages were init'ed in early boot */
1144 if (h
->order
< MAX_ORDER
)
1145 hugetlb_hstate_alloc_pages(h
);
1149 static char * __init
memfmt(char *buf
, unsigned long n
)
1151 if (n
>= (1UL << 30))
1152 sprintf(buf
, "%lu GB", n
>> 30);
1153 else if (n
>= (1UL << 20))
1154 sprintf(buf
, "%lu MB", n
>> 20);
1156 sprintf(buf
, "%lu KB", n
>> 10);
1160 static void __init
report_hugepages(void)
1164 for_each_hstate(h
) {
1166 printk(KERN_INFO
"HugeTLB registered %s page size, "
1167 "pre-allocated %ld pages\n",
1168 memfmt(buf
, huge_page_size(h
)),
1169 h
->free_huge_pages
);
1173 #ifdef CONFIG_HIGHMEM
1174 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1175 nodemask_t
*nodes_allowed
)
1179 if (h
->order
>= MAX_ORDER
)
1182 for_each_node_mask(i
, *nodes_allowed
) {
1183 struct page
*page
, *next
;
1184 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1185 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1186 if (count
>= h
->nr_huge_pages
)
1188 if (PageHighMem(page
))
1190 list_del(&page
->lru
);
1191 update_and_free_page(h
, page
);
1192 h
->free_huge_pages
--;
1193 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1198 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1199 nodemask_t
*nodes_allowed
)
1205 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1206 * balanced by operating on them in a round-robin fashion.
1207 * Returns 1 if an adjustment was made.
1209 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1212 int start_nid
, next_nid
;
1215 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1218 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1220 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1221 next_nid
= start_nid
;
1227 * To shrink on this node, there must be a surplus page
1229 if (!h
->surplus_huge_pages_node
[nid
]) {
1230 next_nid
= hstate_next_node_to_alloc(h
,
1237 * Surplus cannot exceed the total number of pages
1239 if (h
->surplus_huge_pages_node
[nid
] >=
1240 h
->nr_huge_pages_node
[nid
]) {
1241 next_nid
= hstate_next_node_to_free(h
,
1247 h
->surplus_huge_pages
+= delta
;
1248 h
->surplus_huge_pages_node
[nid
] += delta
;
1251 } while (next_nid
!= start_nid
);
1256 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1257 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1258 nodemask_t
*nodes_allowed
)
1260 unsigned long min_count
, ret
;
1262 if (h
->order
>= MAX_ORDER
)
1263 return h
->max_huge_pages
;
1266 * Increase the pool size
1267 * First take pages out of surplus state. Then make up the
1268 * remaining difference by allocating fresh huge pages.
1270 * We might race with alloc_buddy_huge_page() here and be unable
1271 * to convert a surplus huge page to a normal huge page. That is
1272 * not critical, though, it just means the overall size of the
1273 * pool might be one hugepage larger than it needs to be, but
1274 * within all the constraints specified by the sysctls.
1276 spin_lock(&hugetlb_lock
);
1277 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1278 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1282 while (count
> persistent_huge_pages(h
)) {
1284 * If this allocation races such that we no longer need the
1285 * page, free_huge_page will handle it by freeing the page
1286 * and reducing the surplus.
1288 spin_unlock(&hugetlb_lock
);
1289 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1290 spin_lock(&hugetlb_lock
);
1294 /* Bail for signals. Probably ctrl-c from user */
1295 if (signal_pending(current
))
1300 * Decrease the pool size
1301 * First return free pages to the buddy allocator (being careful
1302 * to keep enough around to satisfy reservations). Then place
1303 * pages into surplus state as needed so the pool will shrink
1304 * to the desired size as pages become free.
1306 * By placing pages into the surplus state independent of the
1307 * overcommit value, we are allowing the surplus pool size to
1308 * exceed overcommit. There are few sane options here. Since
1309 * alloc_buddy_huge_page() is checking the global counter,
1310 * though, we'll note that we're not allowed to exceed surplus
1311 * and won't grow the pool anywhere else. Not until one of the
1312 * sysctls are changed, or the surplus pages go out of use.
1314 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1315 min_count
= max(count
, min_count
);
1316 try_to_free_low(h
, min_count
, nodes_allowed
);
1317 while (min_count
< persistent_huge_pages(h
)) {
1318 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1321 while (count
< persistent_huge_pages(h
)) {
1322 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1326 ret
= persistent_huge_pages(h
);
1327 spin_unlock(&hugetlb_lock
);
1331 #define HSTATE_ATTR_RO(_name) \
1332 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1334 #define HSTATE_ATTR(_name) \
1335 static struct kobj_attribute _name##_attr = \
1336 __ATTR(_name, 0644, _name##_show, _name##_store)
1338 static struct kobject
*hugepages_kobj
;
1339 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1341 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1343 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1347 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1348 if (hstate_kobjs
[i
] == kobj
) {
1350 *nidp
= NUMA_NO_NODE
;
1354 return kobj_to_node_hstate(kobj
, nidp
);
1357 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1358 struct kobj_attribute
*attr
, char *buf
)
1361 unsigned long nr_huge_pages
;
1364 h
= kobj_to_hstate(kobj
, &nid
);
1365 if (nid
== NUMA_NO_NODE
)
1366 nr_huge_pages
= h
->nr_huge_pages
;
1368 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1370 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1372 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1373 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1374 const char *buf
, size_t len
)
1378 unsigned long count
;
1380 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1382 err
= strict_strtoul(buf
, 10, &count
);
1386 h
= kobj_to_hstate(kobj
, &nid
);
1387 if (nid
== NUMA_NO_NODE
) {
1389 * global hstate attribute
1391 if (!(obey_mempolicy
&&
1392 init_nodemask_of_mempolicy(nodes_allowed
))) {
1393 NODEMASK_FREE(nodes_allowed
);
1394 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1396 } else if (nodes_allowed
) {
1398 * per node hstate attribute: adjust count to global,
1399 * but restrict alloc/free to the specified node.
1401 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1402 init_nodemask_of_node(nodes_allowed
, nid
);
1404 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1406 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1408 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1409 NODEMASK_FREE(nodes_allowed
);
1414 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1415 struct kobj_attribute
*attr
, char *buf
)
1417 return nr_hugepages_show_common(kobj
, attr
, buf
);
1420 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1421 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1423 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1425 HSTATE_ATTR(nr_hugepages
);
1430 * hstate attribute for optionally mempolicy-based constraint on persistent
1431 * huge page alloc/free.
1433 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1434 struct kobj_attribute
*attr
, char *buf
)
1436 return nr_hugepages_show_common(kobj
, attr
, buf
);
1439 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1440 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1442 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1444 HSTATE_ATTR(nr_hugepages_mempolicy
);
1448 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1449 struct kobj_attribute
*attr
, char *buf
)
1451 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1452 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1454 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1455 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1458 unsigned long input
;
1459 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1461 err
= strict_strtoul(buf
, 10, &input
);
1465 spin_lock(&hugetlb_lock
);
1466 h
->nr_overcommit_huge_pages
= input
;
1467 spin_unlock(&hugetlb_lock
);
1471 HSTATE_ATTR(nr_overcommit_hugepages
);
1473 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1474 struct kobj_attribute
*attr
, char *buf
)
1477 unsigned long free_huge_pages
;
1480 h
= kobj_to_hstate(kobj
, &nid
);
1481 if (nid
== NUMA_NO_NODE
)
1482 free_huge_pages
= h
->free_huge_pages
;
1484 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1486 return sprintf(buf
, "%lu\n", free_huge_pages
);
1488 HSTATE_ATTR_RO(free_hugepages
);
1490 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1491 struct kobj_attribute
*attr
, char *buf
)
1493 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1494 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1496 HSTATE_ATTR_RO(resv_hugepages
);
1498 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1499 struct kobj_attribute
*attr
, char *buf
)
1502 unsigned long surplus_huge_pages
;
1505 h
= kobj_to_hstate(kobj
, &nid
);
1506 if (nid
== NUMA_NO_NODE
)
1507 surplus_huge_pages
= h
->surplus_huge_pages
;
1509 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1511 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1513 HSTATE_ATTR_RO(surplus_hugepages
);
1515 static struct attribute
*hstate_attrs
[] = {
1516 &nr_hugepages_attr
.attr
,
1517 &nr_overcommit_hugepages_attr
.attr
,
1518 &free_hugepages_attr
.attr
,
1519 &resv_hugepages_attr
.attr
,
1520 &surplus_hugepages_attr
.attr
,
1522 &nr_hugepages_mempolicy_attr
.attr
,
1527 static struct attribute_group hstate_attr_group
= {
1528 .attrs
= hstate_attrs
,
1531 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1532 struct kobject
**hstate_kobjs
,
1533 struct attribute_group
*hstate_attr_group
)
1536 int hi
= h
- hstates
;
1538 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1539 if (!hstate_kobjs
[hi
])
1542 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1544 kobject_put(hstate_kobjs
[hi
]);
1549 static void __init
hugetlb_sysfs_init(void)
1554 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1555 if (!hugepages_kobj
)
1558 for_each_hstate(h
) {
1559 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1560 hstate_kobjs
, &hstate_attr_group
);
1562 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1570 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1571 * with node sysdevs in node_devices[] using a parallel array. The array
1572 * index of a node sysdev or _hstate == node id.
1573 * This is here to avoid any static dependency of the node sysdev driver, in
1574 * the base kernel, on the hugetlb module.
1576 struct node_hstate
{
1577 struct kobject
*hugepages_kobj
;
1578 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1580 struct node_hstate node_hstates
[MAX_NUMNODES
];
1583 * A subset of global hstate attributes for node sysdevs
1585 static struct attribute
*per_node_hstate_attrs
[] = {
1586 &nr_hugepages_attr
.attr
,
1587 &free_hugepages_attr
.attr
,
1588 &surplus_hugepages_attr
.attr
,
1592 static struct attribute_group per_node_hstate_attr_group
= {
1593 .attrs
= per_node_hstate_attrs
,
1597 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1598 * Returns node id via non-NULL nidp.
1600 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1604 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1605 struct node_hstate
*nhs
= &node_hstates
[nid
];
1607 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1608 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1620 * Unregister hstate attributes from a single node sysdev.
1621 * No-op if no hstate attributes attached.
1623 void hugetlb_unregister_node(struct node
*node
)
1626 struct node_hstate
*nhs
= &node_hstates
[node
->sysdev
.id
];
1628 if (!nhs
->hugepages_kobj
)
1629 return; /* no hstate attributes */
1632 if (nhs
->hstate_kobjs
[h
- hstates
]) {
1633 kobject_put(nhs
->hstate_kobjs
[h
- hstates
]);
1634 nhs
->hstate_kobjs
[h
- hstates
] = NULL
;
1637 kobject_put(nhs
->hugepages_kobj
);
1638 nhs
->hugepages_kobj
= NULL
;
1642 * hugetlb module exit: unregister hstate attributes from node sysdevs
1645 static void hugetlb_unregister_all_nodes(void)
1650 * disable node sysdev registrations.
1652 register_hugetlbfs_with_node(NULL
, NULL
);
1655 * remove hstate attributes from any nodes that have them.
1657 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1658 hugetlb_unregister_node(&node_devices
[nid
]);
1662 * Register hstate attributes for a single node sysdev.
1663 * No-op if attributes already registered.
1665 void hugetlb_register_node(struct node
*node
)
1668 struct node_hstate
*nhs
= &node_hstates
[node
->sysdev
.id
];
1671 if (nhs
->hugepages_kobj
)
1672 return; /* already allocated */
1674 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1675 &node
->sysdev
.kobj
);
1676 if (!nhs
->hugepages_kobj
)
1679 for_each_hstate(h
) {
1680 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1682 &per_node_hstate_attr_group
);
1684 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1686 h
->name
, node
->sysdev
.id
);
1687 hugetlb_unregister_node(node
);
1694 * hugetlb init time: register hstate attributes for all registered node
1695 * sysdevs of nodes that have memory. All on-line nodes should have
1696 * registered their associated sysdev by this time.
1698 static void hugetlb_register_all_nodes(void)
1702 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1703 struct node
*node
= &node_devices
[nid
];
1704 if (node
->sysdev
.id
== nid
)
1705 hugetlb_register_node(node
);
1709 * Let the node sysdev driver know we're here so it can
1710 * [un]register hstate attributes on node hotplug.
1712 register_hugetlbfs_with_node(hugetlb_register_node
,
1713 hugetlb_unregister_node
);
1715 #else /* !CONFIG_NUMA */
1717 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1725 static void hugetlb_unregister_all_nodes(void) { }
1727 static void hugetlb_register_all_nodes(void) { }
1731 static void __exit
hugetlb_exit(void)
1735 hugetlb_unregister_all_nodes();
1737 for_each_hstate(h
) {
1738 kobject_put(hstate_kobjs
[h
- hstates
]);
1741 kobject_put(hugepages_kobj
);
1743 module_exit(hugetlb_exit
);
1745 static int __init
hugetlb_init(void)
1747 /* Some platform decide whether they support huge pages at boot
1748 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1749 * there is no such support
1751 if (HPAGE_SHIFT
== 0)
1754 if (!size_to_hstate(default_hstate_size
)) {
1755 default_hstate_size
= HPAGE_SIZE
;
1756 if (!size_to_hstate(default_hstate_size
))
1757 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1759 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1760 if (default_hstate_max_huge_pages
)
1761 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1763 hugetlb_init_hstates();
1765 gather_bootmem_prealloc();
1769 hugetlb_sysfs_init();
1771 hugetlb_register_all_nodes();
1775 module_init(hugetlb_init
);
1777 /* Should be called on processing a hugepagesz=... option */
1778 void __init
hugetlb_add_hstate(unsigned order
)
1783 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1784 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1787 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1789 h
= &hstates
[max_hstate
++];
1791 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1792 h
->nr_huge_pages
= 0;
1793 h
->free_huge_pages
= 0;
1794 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1795 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1796 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1797 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1798 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1799 huge_page_size(h
)/1024);
1804 static int __init
hugetlb_nrpages_setup(char *s
)
1807 static unsigned long *last_mhp
;
1810 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1811 * so this hugepages= parameter goes to the "default hstate".
1814 mhp
= &default_hstate_max_huge_pages
;
1816 mhp
= &parsed_hstate
->max_huge_pages
;
1818 if (mhp
== last_mhp
) {
1819 printk(KERN_WARNING
"hugepages= specified twice without "
1820 "interleaving hugepagesz=, ignoring\n");
1824 if (sscanf(s
, "%lu", mhp
) <= 0)
1828 * Global state is always initialized later in hugetlb_init.
1829 * But we need to allocate >= MAX_ORDER hstates here early to still
1830 * use the bootmem allocator.
1832 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1833 hugetlb_hstate_alloc_pages(parsed_hstate
);
1839 __setup("hugepages=", hugetlb_nrpages_setup
);
1841 static int __init
hugetlb_default_setup(char *s
)
1843 default_hstate_size
= memparse(s
, &s
);
1846 __setup("default_hugepagesz=", hugetlb_default_setup
);
1848 static unsigned int cpuset_mems_nr(unsigned int *array
)
1851 unsigned int nr
= 0;
1853 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1859 #ifdef CONFIG_SYSCTL
1860 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1861 struct ctl_table
*table
, int write
,
1862 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1864 struct hstate
*h
= &default_hstate
;
1868 tmp
= h
->max_huge_pages
;
1871 table
->maxlen
= sizeof(unsigned long);
1872 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1875 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
1876 GFP_KERNEL
| __GFP_NORETRY
);
1877 if (!(obey_mempolicy
&&
1878 init_nodemask_of_mempolicy(nodes_allowed
))) {
1879 NODEMASK_FREE(nodes_allowed
);
1880 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1882 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
1884 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1885 NODEMASK_FREE(nodes_allowed
);
1891 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1892 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1895 return hugetlb_sysctl_handler_common(false, table
, write
,
1896 buffer
, length
, ppos
);
1900 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
1901 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1903 return hugetlb_sysctl_handler_common(true, table
, write
,
1904 buffer
, length
, ppos
);
1906 #endif /* CONFIG_NUMA */
1908 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1909 void __user
*buffer
,
1910 size_t *length
, loff_t
*ppos
)
1912 proc_dointvec(table
, write
, buffer
, length
, ppos
);
1913 if (hugepages_treat_as_movable
)
1914 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1916 htlb_alloc_mask
= GFP_HIGHUSER
;
1920 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1921 void __user
*buffer
,
1922 size_t *length
, loff_t
*ppos
)
1924 struct hstate
*h
= &default_hstate
;
1928 tmp
= h
->nr_overcommit_huge_pages
;
1931 table
->maxlen
= sizeof(unsigned long);
1932 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1935 spin_lock(&hugetlb_lock
);
1936 h
->nr_overcommit_huge_pages
= tmp
;
1937 spin_unlock(&hugetlb_lock
);
1943 #endif /* CONFIG_SYSCTL */
1945 void hugetlb_report_meminfo(struct seq_file
*m
)
1947 struct hstate
*h
= &default_hstate
;
1949 "HugePages_Total: %5lu\n"
1950 "HugePages_Free: %5lu\n"
1951 "HugePages_Rsvd: %5lu\n"
1952 "HugePages_Surp: %5lu\n"
1953 "Hugepagesize: %8lu kB\n",
1957 h
->surplus_huge_pages
,
1958 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1961 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1963 struct hstate
*h
= &default_hstate
;
1965 "Node %d HugePages_Total: %5u\n"
1966 "Node %d HugePages_Free: %5u\n"
1967 "Node %d HugePages_Surp: %5u\n",
1968 nid
, h
->nr_huge_pages_node
[nid
],
1969 nid
, h
->free_huge_pages_node
[nid
],
1970 nid
, h
->surplus_huge_pages_node
[nid
]);
1973 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1974 unsigned long hugetlb_total_pages(void)
1976 struct hstate
*h
= &default_hstate
;
1977 return h
->nr_huge_pages
* pages_per_huge_page(h
);
1980 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
1984 spin_lock(&hugetlb_lock
);
1986 * When cpuset is configured, it breaks the strict hugetlb page
1987 * reservation as the accounting is done on a global variable. Such
1988 * reservation is completely rubbish in the presence of cpuset because
1989 * the reservation is not checked against page availability for the
1990 * current cpuset. Application can still potentially OOM'ed by kernel
1991 * with lack of free htlb page in cpuset that the task is in.
1992 * Attempt to enforce strict accounting with cpuset is almost
1993 * impossible (or too ugly) because cpuset is too fluid that
1994 * task or memory node can be dynamically moved between cpusets.
1996 * The change of semantics for shared hugetlb mapping with cpuset is
1997 * undesirable. However, in order to preserve some of the semantics,
1998 * we fall back to check against current free page availability as
1999 * a best attempt and hopefully to minimize the impact of changing
2000 * semantics that cpuset has.
2003 if (gather_surplus_pages(h
, delta
) < 0)
2006 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2007 return_unused_surplus_pages(h
, delta
);
2014 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2017 spin_unlock(&hugetlb_lock
);
2021 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2023 struct resv_map
*reservations
= vma_resv_map(vma
);
2026 * This new VMA should share its siblings reservation map if present.
2027 * The VMA will only ever have a valid reservation map pointer where
2028 * it is being copied for another still existing VMA. As that VMA
2029 * has a reference to the reservation map it cannot dissappear until
2030 * after this open call completes. It is therefore safe to take a
2031 * new reference here without additional locking.
2034 kref_get(&reservations
->refs
);
2037 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2039 struct hstate
*h
= hstate_vma(vma
);
2040 struct resv_map
*reservations
= vma_resv_map(vma
);
2041 unsigned long reserve
;
2042 unsigned long start
;
2046 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2047 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2049 reserve
= (end
- start
) -
2050 region_count(&reservations
->regions
, start
, end
);
2052 kref_put(&reservations
->refs
, resv_map_release
);
2055 hugetlb_acct_memory(h
, -reserve
);
2056 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
2062 * We cannot handle pagefaults against hugetlb pages at all. They cause
2063 * handle_mm_fault() to try to instantiate regular-sized pages in the
2064 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2067 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2073 const struct vm_operations_struct hugetlb_vm_ops
= {
2074 .fault
= hugetlb_vm_op_fault
,
2075 .open
= hugetlb_vm_op_open
,
2076 .close
= hugetlb_vm_op_close
,
2079 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2086 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2088 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2090 entry
= pte_mkyoung(entry
);
2091 entry
= pte_mkhuge(entry
);
2096 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2097 unsigned long address
, pte_t
*ptep
)
2101 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2102 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
2103 update_mmu_cache(vma
, address
, ptep
);
2108 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2109 struct vm_area_struct
*vma
)
2111 pte_t
*src_pte
, *dst_pte
, entry
;
2112 struct page
*ptepage
;
2115 struct hstate
*h
= hstate_vma(vma
);
2116 unsigned long sz
= huge_page_size(h
);
2118 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2120 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2121 src_pte
= huge_pte_offset(src
, addr
);
2124 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2128 /* If the pagetables are shared don't copy or take references */
2129 if (dst_pte
== src_pte
)
2132 spin_lock(&dst
->page_table_lock
);
2133 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2134 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2136 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2137 entry
= huge_ptep_get(src_pte
);
2138 ptepage
= pte_page(entry
);
2140 page_dup_rmap(ptepage
);
2141 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2143 spin_unlock(&src
->page_table_lock
);
2144 spin_unlock(&dst
->page_table_lock
);
2152 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2153 unsigned long end
, struct page
*ref_page
)
2155 struct mm_struct
*mm
= vma
->vm_mm
;
2156 unsigned long address
;
2161 struct hstate
*h
= hstate_vma(vma
);
2162 unsigned long sz
= huge_page_size(h
);
2165 * A page gathering list, protected by per file i_mmap_lock. The
2166 * lock is used to avoid list corruption from multiple unmapping
2167 * of the same page since we are using page->lru.
2169 LIST_HEAD(page_list
);
2171 WARN_ON(!is_vm_hugetlb_page(vma
));
2172 BUG_ON(start
& ~huge_page_mask(h
));
2173 BUG_ON(end
& ~huge_page_mask(h
));
2175 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2176 spin_lock(&mm
->page_table_lock
);
2177 for (address
= start
; address
< end
; address
+= sz
) {
2178 ptep
= huge_pte_offset(mm
, address
);
2182 if (huge_pmd_unshare(mm
, &address
, ptep
))
2186 * If a reference page is supplied, it is because a specific
2187 * page is being unmapped, not a range. Ensure the page we
2188 * are about to unmap is the actual page of interest.
2191 pte
= huge_ptep_get(ptep
);
2192 if (huge_pte_none(pte
))
2194 page
= pte_page(pte
);
2195 if (page
!= ref_page
)
2199 * Mark the VMA as having unmapped its page so that
2200 * future faults in this VMA will fail rather than
2201 * looking like data was lost
2203 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2206 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2207 if (huge_pte_none(pte
))
2210 page
= pte_page(pte
);
2212 set_page_dirty(page
);
2213 list_add(&page
->lru
, &page_list
);
2215 spin_unlock(&mm
->page_table_lock
);
2216 flush_tlb_range(vma
, start
, end
);
2217 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2218 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
2219 page_remove_rmap(page
);
2220 list_del(&page
->lru
);
2225 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2226 unsigned long end
, struct page
*ref_page
)
2228 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2229 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
2230 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2234 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2235 * mappping it owns the reserve page for. The intention is to unmap the page
2236 * from other VMAs and let the children be SIGKILLed if they are faulting the
2239 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2240 struct page
*page
, unsigned long address
)
2242 struct hstate
*h
= hstate_vma(vma
);
2243 struct vm_area_struct
*iter_vma
;
2244 struct address_space
*mapping
;
2245 struct prio_tree_iter iter
;
2249 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2250 * from page cache lookup which is in HPAGE_SIZE units.
2252 address
= address
& huge_page_mask(h
);
2253 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
2254 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
2255 mapping
= (struct address_space
*)page_private(page
);
2258 * Take the mapping lock for the duration of the table walk. As
2259 * this mapping should be shared between all the VMAs,
2260 * __unmap_hugepage_range() is called as the lock is already held
2262 spin_lock(&mapping
->i_mmap_lock
);
2263 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2264 /* Do not unmap the current VMA */
2265 if (iter_vma
== vma
)
2269 * Unmap the page from other VMAs without their own reserves.
2270 * They get marked to be SIGKILLed if they fault in these
2271 * areas. This is because a future no-page fault on this VMA
2272 * could insert a zeroed page instead of the data existing
2273 * from the time of fork. This would look like data corruption
2275 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2276 __unmap_hugepage_range(iter_vma
,
2277 address
, address
+ huge_page_size(h
),
2280 spin_unlock(&mapping
->i_mmap_lock
);
2286 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2288 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2289 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2290 struct page
*pagecache_page
)
2292 struct hstate
*h
= hstate_vma(vma
);
2293 struct page
*old_page
, *new_page
;
2295 int outside_reserve
= 0;
2297 old_page
= pte_page(pte
);
2300 /* If no-one else is actually using this page, avoid the copy
2301 * and just make the page writable */
2302 avoidcopy
= (page_mapcount(old_page
) == 1);
2304 if (!trylock_page(old_page
))
2305 if (PageAnon(old_page
))
2306 page_move_anon_rmap(old_page
, vma
, address
);
2307 set_huge_ptep_writable(vma
, address
, ptep
);
2312 * If the process that created a MAP_PRIVATE mapping is about to
2313 * perform a COW due to a shared page count, attempt to satisfy
2314 * the allocation without using the existing reserves. The pagecache
2315 * page is used to determine if the reserve at this address was
2316 * consumed or not. If reserves were used, a partial faulted mapping
2317 * at the time of fork() could consume its reserves on COW instead
2318 * of the full address range.
2320 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2321 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2322 old_page
!= pagecache_page
)
2323 outside_reserve
= 1;
2325 page_cache_get(old_page
);
2327 /* Drop page_table_lock as buddy allocator may be called */
2328 spin_unlock(&mm
->page_table_lock
);
2329 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2331 if (IS_ERR(new_page
)) {
2332 page_cache_release(old_page
);
2335 * If a process owning a MAP_PRIVATE mapping fails to COW,
2336 * it is due to references held by a child and an insufficient
2337 * huge page pool. To guarantee the original mappers
2338 * reliability, unmap the page from child processes. The child
2339 * may get SIGKILLed if it later faults.
2341 if (outside_reserve
) {
2342 BUG_ON(huge_pte_none(pte
));
2343 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2344 BUG_ON(page_count(old_page
) != 1);
2345 BUG_ON(huge_pte_none(pte
));
2346 spin_lock(&mm
->page_table_lock
);
2347 goto retry_avoidcopy
;
2352 /* Caller expects lock to be held */
2353 spin_lock(&mm
->page_table_lock
);
2354 return -PTR_ERR(new_page
);
2358 * When the original hugepage is shared one, it does not have
2359 * anon_vma prepared.
2361 if (unlikely(anon_vma_prepare(vma
)))
2362 return VM_FAULT_OOM
;
2364 copy_huge_page(new_page
, old_page
, address
, vma
);
2365 __SetPageUptodate(new_page
);
2368 * Retake the page_table_lock to check for racing updates
2369 * before the page tables are altered
2371 spin_lock(&mm
->page_table_lock
);
2372 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2373 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2375 huge_ptep_clear_flush(vma
, address
, ptep
);
2376 set_huge_pte_at(mm
, address
, ptep
,
2377 make_huge_pte(vma
, new_page
, 1));
2378 page_remove_rmap(old_page
);
2379 hugepage_add_anon_rmap(new_page
, vma
, address
);
2380 /* Make the old page be freed below */
2381 new_page
= old_page
;
2383 page_cache_release(new_page
);
2384 page_cache_release(old_page
);
2388 /* Return the pagecache page at a given address within a VMA */
2389 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2390 struct vm_area_struct
*vma
, unsigned long address
)
2392 struct address_space
*mapping
;
2395 mapping
= vma
->vm_file
->f_mapping
;
2396 idx
= vma_hugecache_offset(h
, vma
, address
);
2398 return find_lock_page(mapping
, idx
);
2402 * Return whether there is a pagecache page to back given address within VMA.
2403 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2405 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2406 struct vm_area_struct
*vma
, unsigned long address
)
2408 struct address_space
*mapping
;
2412 mapping
= vma
->vm_file
->f_mapping
;
2413 idx
= vma_hugecache_offset(h
, vma
, address
);
2415 page
= find_get_page(mapping
, idx
);
2418 return page
!= NULL
;
2421 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2422 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2424 struct hstate
*h
= hstate_vma(vma
);
2425 int ret
= VM_FAULT_SIGBUS
;
2429 struct address_space
*mapping
;
2433 * Currently, we are forced to kill the process in the event the
2434 * original mapper has unmapped pages from the child due to a failed
2435 * COW. Warn that such a situation has occured as it may not be obvious
2437 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2439 "PID %d killed due to inadequate hugepage pool\n",
2444 mapping
= vma
->vm_file
->f_mapping
;
2445 idx
= vma_hugecache_offset(h
, vma
, address
);
2448 * Use page lock to guard against racing truncation
2449 * before we get page_table_lock.
2452 page
= find_lock_page(mapping
, idx
);
2454 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2457 page
= alloc_huge_page(vma
, address
, 0);
2459 ret
= -PTR_ERR(page
);
2462 clear_huge_page(page
, address
, huge_page_size(h
));
2463 __SetPageUptodate(page
);
2465 if (vma
->vm_flags
& VM_MAYSHARE
) {
2467 struct inode
*inode
= mapping
->host
;
2469 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2477 spin_lock(&inode
->i_lock
);
2478 inode
->i_blocks
+= blocks_per_huge_page(h
);
2479 spin_unlock(&inode
->i_lock
);
2480 page_dup_rmap(page
);
2483 if (unlikely(anon_vma_prepare(vma
))) {
2485 goto backout_unlocked
;
2487 hugepage_add_new_anon_rmap(page
, vma
, address
);
2490 page_dup_rmap(page
);
2494 * If we are going to COW a private mapping later, we examine the
2495 * pending reservations for this page now. This will ensure that
2496 * any allocations necessary to record that reservation occur outside
2499 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2500 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2502 goto backout_unlocked
;
2505 spin_lock(&mm
->page_table_lock
);
2506 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2511 if (!huge_pte_none(huge_ptep_get(ptep
)))
2514 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2515 && (vma
->vm_flags
& VM_SHARED
)));
2516 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2518 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2519 /* Optimization, do the COW without a second fault */
2520 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2523 spin_unlock(&mm
->page_table_lock
);
2529 spin_unlock(&mm
->page_table_lock
);
2536 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2537 unsigned long address
, unsigned int flags
)
2542 struct page
*page
= NULL
;
2543 struct page
*pagecache_page
= NULL
;
2544 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2545 struct hstate
*h
= hstate_vma(vma
);
2547 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2549 return VM_FAULT_OOM
;
2552 * Serialize hugepage allocation and instantiation, so that we don't
2553 * get spurious allocation failures if two CPUs race to instantiate
2554 * the same page in the page cache.
2556 mutex_lock(&hugetlb_instantiation_mutex
);
2557 entry
= huge_ptep_get(ptep
);
2558 if (huge_pte_none(entry
)) {
2559 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2566 * If we are going to COW the mapping later, we examine the pending
2567 * reservations for this page now. This will ensure that any
2568 * allocations necessary to record that reservation occur outside the
2569 * spinlock. For private mappings, we also lookup the pagecache
2570 * page now as it is used to determine if a reservation has been
2573 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2574 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2579 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2580 pagecache_page
= hugetlbfs_pagecache_page(h
,
2584 if (!pagecache_page
) {
2585 page
= pte_page(entry
);
2589 spin_lock(&mm
->page_table_lock
);
2590 /* Check for a racing update before calling hugetlb_cow */
2591 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2592 goto out_page_table_lock
;
2595 if (flags
& FAULT_FLAG_WRITE
) {
2596 if (!pte_write(entry
)) {
2597 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2599 goto out_page_table_lock
;
2601 entry
= pte_mkdirty(entry
);
2603 entry
= pte_mkyoung(entry
);
2604 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2605 flags
& FAULT_FLAG_WRITE
))
2606 update_mmu_cache(vma
, address
, ptep
);
2608 out_page_table_lock
:
2609 spin_unlock(&mm
->page_table_lock
);
2611 if (pagecache_page
) {
2612 unlock_page(pagecache_page
);
2613 put_page(pagecache_page
);
2619 mutex_unlock(&hugetlb_instantiation_mutex
);
2624 /* Can be overriden by architectures */
2625 __attribute__((weak
)) struct page
*
2626 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2627 pud_t
*pud
, int write
)
2633 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2634 struct page
**pages
, struct vm_area_struct
**vmas
,
2635 unsigned long *position
, int *length
, int i
,
2638 unsigned long pfn_offset
;
2639 unsigned long vaddr
= *position
;
2640 int remainder
= *length
;
2641 struct hstate
*h
= hstate_vma(vma
);
2643 spin_lock(&mm
->page_table_lock
);
2644 while (vaddr
< vma
->vm_end
&& remainder
) {
2650 * Some archs (sparc64, sh*) have multiple pte_ts to
2651 * each hugepage. We have to make sure we get the
2652 * first, for the page indexing below to work.
2654 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2655 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2658 * When coredumping, it suits get_dump_page if we just return
2659 * an error where there's an empty slot with no huge pagecache
2660 * to back it. This way, we avoid allocating a hugepage, and
2661 * the sparse dumpfile avoids allocating disk blocks, but its
2662 * huge holes still show up with zeroes where they need to be.
2664 if (absent
&& (flags
& FOLL_DUMP
) &&
2665 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2671 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2674 spin_unlock(&mm
->page_table_lock
);
2675 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2676 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2677 spin_lock(&mm
->page_table_lock
);
2678 if (!(ret
& VM_FAULT_ERROR
))
2685 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2686 page
= pte_page(huge_ptep_get(pte
));
2689 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2700 if (vaddr
< vma
->vm_end
&& remainder
&&
2701 pfn_offset
< pages_per_huge_page(h
)) {
2703 * We use pfn_offset to avoid touching the pageframes
2704 * of this compound page.
2709 spin_unlock(&mm
->page_table_lock
);
2710 *length
= remainder
;
2713 return i
? i
: -EFAULT
;
2716 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2717 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2719 struct mm_struct
*mm
= vma
->vm_mm
;
2720 unsigned long start
= address
;
2723 struct hstate
*h
= hstate_vma(vma
);
2725 BUG_ON(address
>= end
);
2726 flush_cache_range(vma
, address
, end
);
2728 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2729 spin_lock(&mm
->page_table_lock
);
2730 for (; address
< end
; address
+= huge_page_size(h
)) {
2731 ptep
= huge_pte_offset(mm
, address
);
2734 if (huge_pmd_unshare(mm
, &address
, ptep
))
2736 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2737 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2738 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2739 set_huge_pte_at(mm
, address
, ptep
, pte
);
2742 spin_unlock(&mm
->page_table_lock
);
2743 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2745 flush_tlb_range(vma
, start
, end
);
2748 int hugetlb_reserve_pages(struct inode
*inode
,
2750 struct vm_area_struct
*vma
,
2754 struct hstate
*h
= hstate_inode(inode
);
2757 * Only apply hugepage reservation if asked. At fault time, an
2758 * attempt will be made for VM_NORESERVE to allocate a page
2759 * and filesystem quota without using reserves
2761 if (acctflag
& VM_NORESERVE
)
2765 * Shared mappings base their reservation on the number of pages that
2766 * are already allocated on behalf of the file. Private mappings need
2767 * to reserve the full area even if read-only as mprotect() may be
2768 * called to make the mapping read-write. Assume !vma is a shm mapping
2770 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2771 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2773 struct resv_map
*resv_map
= resv_map_alloc();
2779 set_vma_resv_map(vma
, resv_map
);
2780 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2786 /* There must be enough filesystem quota for the mapping */
2787 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2791 * Check enough hugepages are available for the reservation.
2792 * Hand back the quota if there are not
2794 ret
= hugetlb_acct_memory(h
, chg
);
2796 hugetlb_put_quota(inode
->i_mapping
, chg
);
2801 * Account for the reservations made. Shared mappings record regions
2802 * that have reservations as they are shared by multiple VMAs.
2803 * When the last VMA disappears, the region map says how much
2804 * the reservation was and the page cache tells how much of
2805 * the reservation was consumed. Private mappings are per-VMA and
2806 * only the consumed reservations are tracked. When the VMA
2807 * disappears, the original reservation is the VMA size and the
2808 * consumed reservations are stored in the map. Hence, nothing
2809 * else has to be done for private mappings here
2811 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2812 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2816 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2818 struct hstate
*h
= hstate_inode(inode
);
2819 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2821 spin_lock(&inode
->i_lock
);
2822 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
2823 spin_unlock(&inode
->i_lock
);
2825 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2826 hugetlb_acct_memory(h
, -(chg
- freed
));