2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
10 #include <linux/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>
22 #include <asm/pgtable.h>
24 #include <linux/hugetlb.h>
27 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
28 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
29 unsigned long hugepages_treat_as_movable
;
31 static int max_hstate
;
32 unsigned int default_hstate_idx
;
33 struct hstate hstates
[HUGE_MAX_HSTATE
];
35 __initdata
LIST_HEAD(huge_boot_pages
);
37 /* for command line parsing */
38 static struct hstate
* __initdata parsed_hstate
;
39 static unsigned long __initdata default_hstate_max_huge_pages
;
40 static unsigned long __initdata default_hstate_size
;
42 #define for_each_hstate(h) \
43 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
46 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
48 static DEFINE_SPINLOCK(hugetlb_lock
);
51 * Region tracking -- allows tracking of reservations and instantiated pages
52 * across the pages in a mapping.
54 * The region data structures are protected by a combination of the mmap_sem
55 * and the hugetlb_instantion_mutex. To access or modify a region the caller
56 * must either hold the mmap_sem for write, or the mmap_sem for read and
57 * the hugetlb_instantiation mutex:
59 * down_write(&mm->mmap_sem);
61 * down_read(&mm->mmap_sem);
62 * mutex_lock(&hugetlb_instantiation_mutex);
65 struct list_head link
;
70 static long region_add(struct list_head
*head
, long f
, long t
)
72 struct file_region
*rg
, *nrg
, *trg
;
74 /* Locate the region we are either in or before. */
75 list_for_each_entry(rg
, head
, link
)
79 /* Round our left edge to the current segment if it encloses us. */
83 /* Check for and consume any regions we now overlap with. */
85 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
86 if (&rg
->link
== head
)
91 /* If this area reaches higher then extend our area to
92 * include it completely. If this is not the first area
93 * which we intend to reuse, free it. */
106 static long region_chg(struct list_head
*head
, long f
, long t
)
108 struct file_region
*rg
, *nrg
;
111 /* Locate the region we are before or in. */
112 list_for_each_entry(rg
, head
, link
)
116 /* If we are below the current region then a new region is required.
117 * Subtle, allocate a new region at the position but make it zero
118 * size such that we can guarantee to record the reservation. */
119 if (&rg
->link
== head
|| t
< rg
->from
) {
120 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
125 INIT_LIST_HEAD(&nrg
->link
);
126 list_add(&nrg
->link
, rg
->link
.prev
);
131 /* Round our left edge to the current segment if it encloses us. */
136 /* Check for and consume any regions we now overlap with. */
137 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
138 if (&rg
->link
== head
)
143 /* We overlap with this area, if it extends futher than
144 * us then we must extend ourselves. Account for its
145 * existing reservation. */
150 chg
-= rg
->to
- rg
->from
;
155 static long region_truncate(struct list_head
*head
, long end
)
157 struct file_region
*rg
, *trg
;
160 /* Locate the region we are either in or before. */
161 list_for_each_entry(rg
, head
, link
)
164 if (&rg
->link
== head
)
167 /* If we are in the middle of a region then adjust it. */
168 if (end
> rg
->from
) {
171 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
174 /* Drop any remaining regions. */
175 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
176 if (&rg
->link
== head
)
178 chg
+= rg
->to
- rg
->from
;
185 static long region_count(struct list_head
*head
, long f
, long t
)
187 struct file_region
*rg
;
190 /* Locate each segment we overlap with, and count that overlap. */
191 list_for_each_entry(rg
, head
, link
) {
200 seg_from
= max(rg
->from
, f
);
201 seg_to
= min(rg
->to
, t
);
203 chg
+= seg_to
- seg_from
;
210 * Convert the address within this vma to the page offset within
211 * the mapping, in pagecache page units; huge pages here.
213 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
214 struct vm_area_struct
*vma
, unsigned long address
)
216 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
217 (vma
->vm_pgoff
>> huge_page_order(h
));
221 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
222 * bits of the reservation map pointer, which are always clear due to
225 #define HPAGE_RESV_OWNER (1UL << 0)
226 #define HPAGE_RESV_UNMAPPED (1UL << 1)
227 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
230 * These helpers are used to track how many pages are reserved for
231 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
232 * is guaranteed to have their future faults succeed.
234 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
235 * the reserve counters are updated with the hugetlb_lock held. It is safe
236 * to reset the VMA at fork() time as it is not in use yet and there is no
237 * chance of the global counters getting corrupted as a result of the values.
239 * The private mapping reservation is represented in a subtly different
240 * manner to a shared mapping. A shared mapping has a region map associated
241 * with the underlying file, this region map represents the backing file
242 * pages which have ever had a reservation assigned which this persists even
243 * after the page is instantiated. A private mapping has a region map
244 * associated with the original mmap which is attached to all VMAs which
245 * reference it, this region map represents those offsets which have consumed
246 * reservation ie. where pages have been instantiated.
248 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
250 return (unsigned long)vma
->vm_private_data
;
253 static void set_vma_private_data(struct vm_area_struct
*vma
,
256 vma
->vm_private_data
= (void *)value
;
261 struct list_head regions
;
264 struct resv_map
*resv_map_alloc(void)
266 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
270 kref_init(&resv_map
->refs
);
271 INIT_LIST_HEAD(&resv_map
->regions
);
276 void resv_map_release(struct kref
*ref
)
278 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
280 /* Clear out any active regions before we release the map. */
281 region_truncate(&resv_map
->regions
, 0);
285 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
287 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
288 if (!(vma
->vm_flags
& VM_SHARED
))
289 return (struct resv_map
*)(get_vma_private_data(vma
) &
294 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
296 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
297 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
299 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
300 HPAGE_RESV_MASK
) | (unsigned long)map
);
303 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
305 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
306 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
308 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
311 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
313 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
315 return (get_vma_private_data(vma
) & flag
) != 0;
318 /* Decrement the reserved pages in the hugepage pool by one */
319 static void decrement_hugepage_resv_vma(struct hstate
*h
,
320 struct vm_area_struct
*vma
)
322 if (vma
->vm_flags
& VM_NORESERVE
)
325 if (vma
->vm_flags
& VM_SHARED
) {
326 /* Shared mappings always use reserves */
327 h
->resv_huge_pages
--;
328 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
330 * Only the process that called mmap() has reserves for
333 h
->resv_huge_pages
--;
337 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
338 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
340 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
341 if (!(vma
->vm_flags
& VM_SHARED
))
342 vma
->vm_private_data
= (void *)0;
345 /* Returns true if the VMA has associated reserve pages */
346 static int vma_has_reserves(struct vm_area_struct
*vma
)
348 if (vma
->vm_flags
& VM_SHARED
)
350 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
355 static void clear_huge_page(struct page
*page
,
356 unsigned long addr
, unsigned long sz
)
361 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
363 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
367 static void copy_huge_page(struct page
*dst
, struct page
*src
,
368 unsigned long addr
, struct vm_area_struct
*vma
)
371 struct hstate
*h
= hstate_vma(vma
);
374 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
376 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
380 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
382 int nid
= page_to_nid(page
);
383 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
384 h
->free_huge_pages
++;
385 h
->free_huge_pages_node
[nid
]++;
388 static struct page
*dequeue_huge_page(struct hstate
*h
)
391 struct page
*page
= NULL
;
393 for (nid
= 0; nid
< MAX_NUMNODES
; ++nid
) {
394 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
395 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
397 list_del(&page
->lru
);
398 h
->free_huge_pages
--;
399 h
->free_huge_pages_node
[nid
]--;
406 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
407 struct vm_area_struct
*vma
,
408 unsigned long address
, int avoid_reserve
)
411 struct page
*page
= NULL
;
412 struct mempolicy
*mpol
;
413 nodemask_t
*nodemask
;
414 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
415 htlb_alloc_mask
, &mpol
, &nodemask
);
420 * A child process with MAP_PRIVATE mappings created by their parent
421 * have no page reserves. This check ensures that reservations are
422 * not "stolen". The child may still get SIGKILLed
424 if (!vma_has_reserves(vma
) &&
425 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
428 /* If reserves cannot be used, ensure enough pages are in the pool */
429 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
432 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
433 MAX_NR_ZONES
- 1, nodemask
) {
434 nid
= zone_to_nid(zone
);
435 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
436 !list_empty(&h
->hugepage_freelists
[nid
])) {
437 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
439 list_del(&page
->lru
);
440 h
->free_huge_pages
--;
441 h
->free_huge_pages_node
[nid
]--;
444 decrement_hugepage_resv_vma(h
, vma
);
453 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
458 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
459 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
460 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
461 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
462 1 << PG_private
| 1<< PG_writeback
);
464 set_compound_page_dtor(page
, NULL
);
465 set_page_refcounted(page
);
466 arch_release_hugepage(page
);
467 __free_pages(page
, huge_page_order(h
));
470 struct hstate
*size_to_hstate(unsigned long size
)
475 if (huge_page_size(h
) == size
)
481 static void free_huge_page(struct page
*page
)
484 * Can't pass hstate in here because it is called from the
485 * compound page destructor.
487 struct hstate
*h
= page_hstate(page
);
488 int nid
= page_to_nid(page
);
489 struct address_space
*mapping
;
491 mapping
= (struct address_space
*) page_private(page
);
492 set_page_private(page
, 0);
493 BUG_ON(page_count(page
));
494 INIT_LIST_HEAD(&page
->lru
);
496 spin_lock(&hugetlb_lock
);
497 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
498 update_and_free_page(h
, page
);
499 h
->surplus_huge_pages
--;
500 h
->surplus_huge_pages_node
[nid
]--;
502 enqueue_huge_page(h
, page
);
504 spin_unlock(&hugetlb_lock
);
506 hugetlb_put_quota(mapping
, 1);
510 * Increment or decrement surplus_huge_pages. Keep node-specific counters
511 * balanced by operating on them in a round-robin fashion.
512 * Returns 1 if an adjustment was made.
514 static int adjust_pool_surplus(struct hstate
*h
, int delta
)
520 VM_BUG_ON(delta
!= -1 && delta
!= 1);
522 nid
= next_node(nid
, node_online_map
);
523 if (nid
== MAX_NUMNODES
)
524 nid
= first_node(node_online_map
);
526 /* To shrink on this node, there must be a surplus page */
527 if (delta
< 0 && !h
->surplus_huge_pages_node
[nid
])
529 /* Surplus cannot exceed the total number of pages */
530 if (delta
> 0 && h
->surplus_huge_pages_node
[nid
] >=
531 h
->nr_huge_pages_node
[nid
])
534 h
->surplus_huge_pages
+= delta
;
535 h
->surplus_huge_pages_node
[nid
] += delta
;
538 } while (nid
!= prev_nid
);
544 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
546 set_compound_page_dtor(page
, free_huge_page
);
547 spin_lock(&hugetlb_lock
);
549 h
->nr_huge_pages_node
[nid
]++;
550 spin_unlock(&hugetlb_lock
);
551 put_page(page
); /* free it into the hugepage allocator */
554 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
558 if (h
->order
>= MAX_ORDER
)
561 page
= alloc_pages_node(nid
,
562 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
563 __GFP_REPEAT
|__GFP_NOWARN
,
566 if (arch_prepare_hugepage(page
)) {
567 __free_pages(page
, HUGETLB_PAGE_ORDER
);
570 prep_new_huge_page(h
, page
, nid
);
577 * Use a helper variable to find the next node and then
578 * copy it back to hugetlb_next_nid afterwards:
579 * otherwise there's a window in which a racer might
580 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
581 * But we don't need to use a spin_lock here: it really
582 * doesn't matter if occasionally a racer chooses the
583 * same nid as we do. Move nid forward in the mask even
584 * if we just successfully allocated a hugepage so that
585 * the next caller gets hugepages on the next node.
587 static int hstate_next_node(struct hstate
*h
)
590 next_nid
= next_node(h
->hugetlb_next_nid
, node_online_map
);
591 if (next_nid
== MAX_NUMNODES
)
592 next_nid
= first_node(node_online_map
);
593 h
->hugetlb_next_nid
= next_nid
;
597 static int alloc_fresh_huge_page(struct hstate
*h
)
604 start_nid
= h
->hugetlb_next_nid
;
607 page
= alloc_fresh_huge_page_node(h
, h
->hugetlb_next_nid
);
610 next_nid
= hstate_next_node(h
);
611 } while (!page
&& h
->hugetlb_next_nid
!= start_nid
);
614 count_vm_event(HTLB_BUDDY_PGALLOC
);
616 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
621 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
622 struct vm_area_struct
*vma
, unsigned long address
)
627 if (h
->order
>= MAX_ORDER
)
631 * Assume we will successfully allocate the surplus page to
632 * prevent racing processes from causing the surplus to exceed
635 * This however introduces a different race, where a process B
636 * tries to grow the static hugepage pool while alloc_pages() is
637 * called by process A. B will only examine the per-node
638 * counters in determining if surplus huge pages can be
639 * converted to normal huge pages in adjust_pool_surplus(). A
640 * won't be able to increment the per-node counter, until the
641 * lock is dropped by B, but B doesn't drop hugetlb_lock until
642 * no more huge pages can be converted from surplus to normal
643 * state (and doesn't try to convert again). Thus, we have a
644 * case where a surplus huge page exists, the pool is grown, and
645 * the surplus huge page still exists after, even though it
646 * should just have been converted to a normal huge page. This
647 * does not leak memory, though, as the hugepage will be freed
648 * once it is out of use. It also does not allow the counters to
649 * go out of whack in adjust_pool_surplus() as we don't modify
650 * the node values until we've gotten the hugepage and only the
651 * per-node value is checked there.
653 spin_lock(&hugetlb_lock
);
654 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
655 spin_unlock(&hugetlb_lock
);
659 h
->surplus_huge_pages
++;
661 spin_unlock(&hugetlb_lock
);
663 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
664 __GFP_REPEAT
|__GFP_NOWARN
,
667 spin_lock(&hugetlb_lock
);
670 * This page is now managed by the hugetlb allocator and has
671 * no users -- drop the buddy allocator's reference.
673 put_page_testzero(page
);
674 VM_BUG_ON(page_count(page
));
675 nid
= page_to_nid(page
);
676 set_compound_page_dtor(page
, free_huge_page
);
678 * We incremented the global counters already
680 h
->nr_huge_pages_node
[nid
]++;
681 h
->surplus_huge_pages_node
[nid
]++;
682 __count_vm_event(HTLB_BUDDY_PGALLOC
);
685 h
->surplus_huge_pages
--;
686 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
688 spin_unlock(&hugetlb_lock
);
694 * Increase the hugetlb pool such that it can accomodate a reservation
697 static int gather_surplus_pages(struct hstate
*h
, int delta
)
699 struct list_head surplus_list
;
700 struct page
*page
, *tmp
;
702 int needed
, allocated
;
704 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
706 h
->resv_huge_pages
+= delta
;
711 INIT_LIST_HEAD(&surplus_list
);
715 spin_unlock(&hugetlb_lock
);
716 for (i
= 0; i
< needed
; i
++) {
717 page
= alloc_buddy_huge_page(h
, NULL
, 0);
720 * We were not able to allocate enough pages to
721 * satisfy the entire reservation so we free what
722 * we've allocated so far.
724 spin_lock(&hugetlb_lock
);
729 list_add(&page
->lru
, &surplus_list
);
734 * After retaking hugetlb_lock, we need to recalculate 'needed'
735 * because either resv_huge_pages or free_huge_pages may have changed.
737 spin_lock(&hugetlb_lock
);
738 needed
= (h
->resv_huge_pages
+ delta
) -
739 (h
->free_huge_pages
+ allocated
);
744 * The surplus_list now contains _at_least_ the number of extra pages
745 * needed to accomodate the reservation. Add the appropriate number
746 * of pages to the hugetlb pool and free the extras back to the buddy
747 * allocator. Commit the entire reservation here to prevent another
748 * process from stealing the pages as they are added to the pool but
749 * before they are reserved.
752 h
->resv_huge_pages
+= delta
;
755 /* Free the needed pages to the hugetlb pool */
756 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
759 list_del(&page
->lru
);
760 enqueue_huge_page(h
, page
);
763 /* Free unnecessary surplus pages to the buddy allocator */
764 if (!list_empty(&surplus_list
)) {
765 spin_unlock(&hugetlb_lock
);
766 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
767 list_del(&page
->lru
);
769 * The page has a reference count of zero already, so
770 * call free_huge_page directly instead of using
771 * put_page. This must be done with hugetlb_lock
772 * unlocked which is safe because free_huge_page takes
773 * hugetlb_lock before deciding how to free the page.
775 free_huge_page(page
);
777 spin_lock(&hugetlb_lock
);
784 * When releasing a hugetlb pool reservation, any surplus pages that were
785 * allocated to satisfy the reservation must be explicitly freed if they were
788 static void return_unused_surplus_pages(struct hstate
*h
,
789 unsigned long unused_resv_pages
)
793 unsigned long nr_pages
;
796 * We want to release as many surplus pages as possible, spread
797 * evenly across all nodes. Iterate across all nodes until we
798 * can no longer free unreserved surplus pages. This occurs when
799 * the nodes with surplus pages have no free pages.
801 unsigned long remaining_iterations
= num_online_nodes();
803 /* Uncommit the reservation */
804 h
->resv_huge_pages
-= unused_resv_pages
;
806 /* Cannot return gigantic pages currently */
807 if (h
->order
>= MAX_ORDER
)
810 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
812 while (remaining_iterations
-- && nr_pages
) {
813 nid
= next_node(nid
, node_online_map
);
814 if (nid
== MAX_NUMNODES
)
815 nid
= first_node(node_online_map
);
817 if (!h
->surplus_huge_pages_node
[nid
])
820 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
821 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
823 list_del(&page
->lru
);
824 update_and_free_page(h
, page
);
825 h
->free_huge_pages
--;
826 h
->free_huge_pages_node
[nid
]--;
827 h
->surplus_huge_pages
--;
828 h
->surplus_huge_pages_node
[nid
]--;
830 remaining_iterations
= num_online_nodes();
836 * Determine if the huge page at addr within the vma has an associated
837 * reservation. Where it does not we will need to logically increase
838 * reservation and actually increase quota before an allocation can occur.
839 * Where any new reservation would be required the reservation change is
840 * prepared, but not committed. Once the page has been quota'd allocated
841 * an instantiated the change should be committed via vma_commit_reservation.
842 * No action is required on failure.
844 static int vma_needs_reservation(struct hstate
*h
,
845 struct vm_area_struct
*vma
, unsigned long addr
)
847 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
848 struct inode
*inode
= mapping
->host
;
850 if (vma
->vm_flags
& VM_SHARED
) {
851 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
852 return region_chg(&inode
->i_mapping
->private_list
,
855 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
860 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
861 struct resv_map
*reservations
= vma_resv_map(vma
);
863 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
869 static void vma_commit_reservation(struct hstate
*h
,
870 struct vm_area_struct
*vma
, unsigned long addr
)
872 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
873 struct inode
*inode
= mapping
->host
;
875 if (vma
->vm_flags
& VM_SHARED
) {
876 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
877 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
879 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
880 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
881 struct resv_map
*reservations
= vma_resv_map(vma
);
883 /* Mark this page used in the map. */
884 region_add(&reservations
->regions
, idx
, idx
+ 1);
888 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
889 unsigned long addr
, int avoid_reserve
)
891 struct hstate
*h
= hstate_vma(vma
);
893 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
894 struct inode
*inode
= mapping
->host
;
898 * Processes that did not create the mapping will have no reserves and
899 * will not have accounted against quota. Check that the quota can be
900 * made before satisfying the allocation
901 * MAP_NORESERVE mappings may also need pages and quota allocated
902 * if no reserve mapping overlaps.
904 chg
= vma_needs_reservation(h
, vma
, addr
);
908 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
909 return ERR_PTR(-ENOSPC
);
911 spin_lock(&hugetlb_lock
);
912 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
913 spin_unlock(&hugetlb_lock
);
916 page
= alloc_buddy_huge_page(h
, vma
, addr
);
918 hugetlb_put_quota(inode
->i_mapping
, chg
);
919 return ERR_PTR(-VM_FAULT_OOM
);
923 set_page_refcounted(page
);
924 set_page_private(page
, (unsigned long) mapping
);
926 vma_commit_reservation(h
, vma
, addr
);
931 __attribute__((weak
)) int alloc_bootmem_huge_page(struct hstate
*h
)
933 struct huge_bootmem_page
*m
;
934 int nr_nodes
= nodes_weight(node_online_map
);
939 addr
= __alloc_bootmem_node_nopanic(
940 NODE_DATA(h
->hugetlb_next_nid
),
941 huge_page_size(h
), huge_page_size(h
), 0);
945 * Use the beginning of the huge page to store the
946 * huge_bootmem_page struct (until gather_bootmem
947 * puts them into the mem_map).
959 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
960 /* Put them into a private list first because mem_map is not up yet */
961 list_add(&m
->list
, &huge_boot_pages
);
966 /* Put bootmem huge pages into the standard lists after mem_map is up */
967 static void __init
gather_bootmem_prealloc(void)
969 struct huge_bootmem_page
*m
;
971 list_for_each_entry(m
, &huge_boot_pages
, list
) {
972 struct page
*page
= virt_to_page(m
);
973 struct hstate
*h
= m
->hstate
;
974 __ClearPageReserved(page
);
975 WARN_ON(page_count(page
) != 1);
976 prep_compound_page(page
, h
->order
);
977 prep_new_huge_page(h
, page
, page_to_nid(page
));
981 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
985 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
986 if (h
->order
>= MAX_ORDER
) {
987 if (!alloc_bootmem_huge_page(h
))
989 } else if (!alloc_fresh_huge_page(h
))
992 h
->max_huge_pages
= i
;
995 static void __init
hugetlb_init_hstates(void)
1000 /* oversize hugepages were init'ed in early boot */
1001 if (h
->order
< MAX_ORDER
)
1002 hugetlb_hstate_alloc_pages(h
);
1006 static char * __init
memfmt(char *buf
, unsigned long n
)
1008 if (n
>= (1UL << 30))
1009 sprintf(buf
, "%lu GB", n
>> 30);
1010 else if (n
>= (1UL << 20))
1011 sprintf(buf
, "%lu MB", n
>> 20);
1013 sprintf(buf
, "%lu KB", n
>> 10);
1017 static void __init
report_hugepages(void)
1021 for_each_hstate(h
) {
1023 printk(KERN_INFO
"HugeTLB registered %s page size, "
1024 "pre-allocated %ld pages\n",
1025 memfmt(buf
, huge_page_size(h
)),
1026 h
->free_huge_pages
);
1030 #ifdef CONFIG_HIGHMEM
1031 static void try_to_free_low(struct hstate
*h
, unsigned long count
)
1035 if (h
->order
>= MAX_ORDER
)
1038 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
1039 struct page
*page
, *next
;
1040 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1041 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1042 if (count
>= h
->nr_huge_pages
)
1044 if (PageHighMem(page
))
1046 list_del(&page
->lru
);
1047 update_and_free_page(h
, page
);
1048 h
->free_huge_pages
--;
1049 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1054 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
)
1059 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1060 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
)
1062 unsigned long min_count
, ret
;
1064 if (h
->order
>= MAX_ORDER
)
1065 return h
->max_huge_pages
;
1068 * Increase the pool size
1069 * First take pages out of surplus state. Then make up the
1070 * remaining difference by allocating fresh huge pages.
1072 * We might race with alloc_buddy_huge_page() here and be unable
1073 * to convert a surplus huge page to a normal huge page. That is
1074 * not critical, though, it just means the overall size of the
1075 * pool might be one hugepage larger than it needs to be, but
1076 * within all the constraints specified by the sysctls.
1078 spin_lock(&hugetlb_lock
);
1079 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1080 if (!adjust_pool_surplus(h
, -1))
1084 while (count
> persistent_huge_pages(h
)) {
1086 * If this allocation races such that we no longer need the
1087 * page, free_huge_page will handle it by freeing the page
1088 * and reducing the surplus.
1090 spin_unlock(&hugetlb_lock
);
1091 ret
= alloc_fresh_huge_page(h
);
1092 spin_lock(&hugetlb_lock
);
1099 * Decrease the pool size
1100 * First return free pages to the buddy allocator (being careful
1101 * to keep enough around to satisfy reservations). Then place
1102 * pages into surplus state as needed so the pool will shrink
1103 * to the desired size as pages become free.
1105 * By placing pages into the surplus state independent of the
1106 * overcommit value, we are allowing the surplus pool size to
1107 * exceed overcommit. There are few sane options here. Since
1108 * alloc_buddy_huge_page() is checking the global counter,
1109 * though, we'll note that we're not allowed to exceed surplus
1110 * and won't grow the pool anywhere else. Not until one of the
1111 * sysctls are changed, or the surplus pages go out of use.
1113 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1114 min_count
= max(count
, min_count
);
1115 try_to_free_low(h
, min_count
);
1116 while (min_count
< persistent_huge_pages(h
)) {
1117 struct page
*page
= dequeue_huge_page(h
);
1120 update_and_free_page(h
, page
);
1122 while (count
< persistent_huge_pages(h
)) {
1123 if (!adjust_pool_surplus(h
, 1))
1127 ret
= persistent_huge_pages(h
);
1128 spin_unlock(&hugetlb_lock
);
1132 #define HSTATE_ATTR_RO(_name) \
1133 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1135 #define HSTATE_ATTR(_name) \
1136 static struct kobj_attribute _name##_attr = \
1137 __ATTR(_name, 0644, _name##_show, _name##_store)
1139 static struct kobject
*hugepages_kobj
;
1140 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1142 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
)
1145 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1146 if (hstate_kobjs
[i
] == kobj
)
1152 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1153 struct kobj_attribute
*attr
, char *buf
)
1155 struct hstate
*h
= kobj_to_hstate(kobj
);
1156 return sprintf(buf
, "%lu\n", h
->nr_huge_pages
);
1158 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1159 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1162 unsigned long input
;
1163 struct hstate
*h
= kobj_to_hstate(kobj
);
1165 err
= strict_strtoul(buf
, 10, &input
);
1169 h
->max_huge_pages
= set_max_huge_pages(h
, input
);
1173 HSTATE_ATTR(nr_hugepages
);
1175 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1176 struct kobj_attribute
*attr
, char *buf
)
1178 struct hstate
*h
= kobj_to_hstate(kobj
);
1179 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1181 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1182 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1185 unsigned long input
;
1186 struct hstate
*h
= kobj_to_hstate(kobj
);
1188 err
= strict_strtoul(buf
, 10, &input
);
1192 spin_lock(&hugetlb_lock
);
1193 h
->nr_overcommit_huge_pages
= input
;
1194 spin_unlock(&hugetlb_lock
);
1198 HSTATE_ATTR(nr_overcommit_hugepages
);
1200 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1201 struct kobj_attribute
*attr
, char *buf
)
1203 struct hstate
*h
= kobj_to_hstate(kobj
);
1204 return sprintf(buf
, "%lu\n", h
->free_huge_pages
);
1206 HSTATE_ATTR_RO(free_hugepages
);
1208 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1209 struct kobj_attribute
*attr
, char *buf
)
1211 struct hstate
*h
= kobj_to_hstate(kobj
);
1212 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1214 HSTATE_ATTR_RO(resv_hugepages
);
1216 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1217 struct kobj_attribute
*attr
, char *buf
)
1219 struct hstate
*h
= kobj_to_hstate(kobj
);
1220 return sprintf(buf
, "%lu\n", h
->surplus_huge_pages
);
1222 HSTATE_ATTR_RO(surplus_hugepages
);
1224 static struct attribute
*hstate_attrs
[] = {
1225 &nr_hugepages_attr
.attr
,
1226 &nr_overcommit_hugepages_attr
.attr
,
1227 &free_hugepages_attr
.attr
,
1228 &resv_hugepages_attr
.attr
,
1229 &surplus_hugepages_attr
.attr
,
1233 static struct attribute_group hstate_attr_group
= {
1234 .attrs
= hstate_attrs
,
1237 static int __init
hugetlb_sysfs_add_hstate(struct hstate
*h
)
1241 hstate_kobjs
[h
- hstates
] = kobject_create_and_add(h
->name
,
1243 if (!hstate_kobjs
[h
- hstates
])
1246 retval
= sysfs_create_group(hstate_kobjs
[h
- hstates
],
1247 &hstate_attr_group
);
1249 kobject_put(hstate_kobjs
[h
- hstates
]);
1254 static void __init
hugetlb_sysfs_init(void)
1259 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1260 if (!hugepages_kobj
)
1263 for_each_hstate(h
) {
1264 err
= hugetlb_sysfs_add_hstate(h
);
1266 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1271 static void __exit
hugetlb_exit(void)
1275 for_each_hstate(h
) {
1276 kobject_put(hstate_kobjs
[h
- hstates
]);
1279 kobject_put(hugepages_kobj
);
1281 module_exit(hugetlb_exit
);
1283 static int __init
hugetlb_init(void)
1285 BUILD_BUG_ON(HPAGE_SHIFT
== 0);
1287 if (!size_to_hstate(default_hstate_size
)) {
1288 default_hstate_size
= HPAGE_SIZE
;
1289 if (!size_to_hstate(default_hstate_size
))
1290 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1292 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1293 if (default_hstate_max_huge_pages
)
1294 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1296 hugetlb_init_hstates();
1298 gather_bootmem_prealloc();
1302 hugetlb_sysfs_init();
1306 module_init(hugetlb_init
);
1308 /* Should be called on processing a hugepagesz=... option */
1309 void __init
hugetlb_add_hstate(unsigned order
)
1314 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1315 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1318 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1320 h
= &hstates
[max_hstate
++];
1322 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1323 h
->nr_huge_pages
= 0;
1324 h
->free_huge_pages
= 0;
1325 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1326 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1327 h
->hugetlb_next_nid
= first_node(node_online_map
);
1328 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1329 huge_page_size(h
)/1024);
1334 static int __init
hugetlb_nrpages_setup(char *s
)
1337 static unsigned long *last_mhp
;
1340 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1341 * so this hugepages= parameter goes to the "default hstate".
1344 mhp
= &default_hstate_max_huge_pages
;
1346 mhp
= &parsed_hstate
->max_huge_pages
;
1348 if (mhp
== last_mhp
) {
1349 printk(KERN_WARNING
"hugepages= specified twice without "
1350 "interleaving hugepagesz=, ignoring\n");
1354 if (sscanf(s
, "%lu", mhp
) <= 0)
1358 * Global state is always initialized later in hugetlb_init.
1359 * But we need to allocate >= MAX_ORDER hstates here early to still
1360 * use the bootmem allocator.
1362 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1363 hugetlb_hstate_alloc_pages(parsed_hstate
);
1369 __setup("hugepages=", hugetlb_nrpages_setup
);
1371 static int __init
hugetlb_default_setup(char *s
)
1373 default_hstate_size
= memparse(s
, &s
);
1376 __setup("default_hugepagesz=", hugetlb_default_setup
);
1378 static unsigned int cpuset_mems_nr(unsigned int *array
)
1381 unsigned int nr
= 0;
1383 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1389 #ifdef CONFIG_SYSCTL
1390 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1391 struct file
*file
, void __user
*buffer
,
1392 size_t *length
, loff_t
*ppos
)
1394 struct hstate
*h
= &default_hstate
;
1398 tmp
= h
->max_huge_pages
;
1401 table
->maxlen
= sizeof(unsigned long);
1402 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1405 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
);
1410 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1411 struct file
*file
, void __user
*buffer
,
1412 size_t *length
, loff_t
*ppos
)
1414 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
1415 if (hugepages_treat_as_movable
)
1416 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1418 htlb_alloc_mask
= GFP_HIGHUSER
;
1422 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1423 struct file
*file
, void __user
*buffer
,
1424 size_t *length
, loff_t
*ppos
)
1426 struct hstate
*h
= &default_hstate
;
1430 tmp
= h
->nr_overcommit_huge_pages
;
1433 table
->maxlen
= sizeof(unsigned long);
1434 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1437 spin_lock(&hugetlb_lock
);
1438 h
->nr_overcommit_huge_pages
= tmp
;
1439 spin_unlock(&hugetlb_lock
);
1445 #endif /* CONFIG_SYSCTL */
1447 int hugetlb_report_meminfo(char *buf
)
1449 struct hstate
*h
= &default_hstate
;
1451 "HugePages_Total: %5lu\n"
1452 "HugePages_Free: %5lu\n"
1453 "HugePages_Rsvd: %5lu\n"
1454 "HugePages_Surp: %5lu\n"
1455 "Hugepagesize: %5lu kB\n",
1459 h
->surplus_huge_pages
,
1460 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1463 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1465 struct hstate
*h
= &default_hstate
;
1467 "Node %d HugePages_Total: %5u\n"
1468 "Node %d HugePages_Free: %5u\n"
1469 "Node %d HugePages_Surp: %5u\n",
1470 nid
, h
->nr_huge_pages_node
[nid
],
1471 nid
, h
->free_huge_pages_node
[nid
],
1472 nid
, h
->surplus_huge_pages_node
[nid
]);
1475 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1476 unsigned long hugetlb_total_pages(void)
1478 struct hstate
*h
= &default_hstate
;
1479 return h
->nr_huge_pages
* pages_per_huge_page(h
);
1482 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
1486 spin_lock(&hugetlb_lock
);
1488 * When cpuset is configured, it breaks the strict hugetlb page
1489 * reservation as the accounting is done on a global variable. Such
1490 * reservation is completely rubbish in the presence of cpuset because
1491 * the reservation is not checked against page availability for the
1492 * current cpuset. Application can still potentially OOM'ed by kernel
1493 * with lack of free htlb page in cpuset that the task is in.
1494 * Attempt to enforce strict accounting with cpuset is almost
1495 * impossible (or too ugly) because cpuset is too fluid that
1496 * task or memory node can be dynamically moved between cpusets.
1498 * The change of semantics for shared hugetlb mapping with cpuset is
1499 * undesirable. However, in order to preserve some of the semantics,
1500 * we fall back to check against current free page availability as
1501 * a best attempt and hopefully to minimize the impact of changing
1502 * semantics that cpuset has.
1505 if (gather_surplus_pages(h
, delta
) < 0)
1508 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
1509 return_unused_surplus_pages(h
, delta
);
1516 return_unused_surplus_pages(h
, (unsigned long) -delta
);
1519 spin_unlock(&hugetlb_lock
);
1523 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
1525 struct resv_map
*reservations
= vma_resv_map(vma
);
1528 * This new VMA should share its siblings reservation map if present.
1529 * The VMA will only ever have a valid reservation map pointer where
1530 * it is being copied for another still existing VMA. As that VMA
1531 * has a reference to the reservation map it cannot dissappear until
1532 * after this open call completes. It is therefore safe to take a
1533 * new reference here without additional locking.
1536 kref_get(&reservations
->refs
);
1539 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
1541 struct hstate
*h
= hstate_vma(vma
);
1542 struct resv_map
*reservations
= vma_resv_map(vma
);
1543 unsigned long reserve
;
1544 unsigned long start
;
1548 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
1549 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
1551 reserve
= (end
- start
) -
1552 region_count(&reservations
->regions
, start
, end
);
1554 kref_put(&reservations
->refs
, resv_map_release
);
1557 hugetlb_acct_memory(h
, -reserve
);
1558 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
1564 * We cannot handle pagefaults against hugetlb pages at all. They cause
1565 * handle_mm_fault() to try to instantiate regular-sized pages in the
1566 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1569 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1575 struct vm_operations_struct hugetlb_vm_ops
= {
1576 .fault
= hugetlb_vm_op_fault
,
1577 .open
= hugetlb_vm_op_open
,
1578 .close
= hugetlb_vm_op_close
,
1581 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
1588 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
1590 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
1592 entry
= pte_mkyoung(entry
);
1593 entry
= pte_mkhuge(entry
);
1598 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
1599 unsigned long address
, pte_t
*ptep
)
1603 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
1604 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
1605 update_mmu_cache(vma
, address
, entry
);
1610 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
1611 struct vm_area_struct
*vma
)
1613 pte_t
*src_pte
, *dst_pte
, entry
;
1614 struct page
*ptepage
;
1617 struct hstate
*h
= hstate_vma(vma
);
1618 unsigned long sz
= huge_page_size(h
);
1620 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
1622 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
1623 src_pte
= huge_pte_offset(src
, addr
);
1626 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
1630 /* If the pagetables are shared don't copy or take references */
1631 if (dst_pte
== src_pte
)
1634 spin_lock(&dst
->page_table_lock
);
1635 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
1636 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
1638 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
1639 entry
= huge_ptep_get(src_pte
);
1640 ptepage
= pte_page(entry
);
1642 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
1644 spin_unlock(&src
->page_table_lock
);
1645 spin_unlock(&dst
->page_table_lock
);
1653 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1654 unsigned long end
, struct page
*ref_page
)
1656 struct mm_struct
*mm
= vma
->vm_mm
;
1657 unsigned long address
;
1662 struct hstate
*h
= hstate_vma(vma
);
1663 unsigned long sz
= huge_page_size(h
);
1666 * A page gathering list, protected by per file i_mmap_lock. The
1667 * lock is used to avoid list corruption from multiple unmapping
1668 * of the same page since we are using page->lru.
1670 LIST_HEAD(page_list
);
1672 WARN_ON(!is_vm_hugetlb_page(vma
));
1673 BUG_ON(start
& ~huge_page_mask(h
));
1674 BUG_ON(end
& ~huge_page_mask(h
));
1676 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1677 spin_lock(&mm
->page_table_lock
);
1678 for (address
= start
; address
< end
; address
+= sz
) {
1679 ptep
= huge_pte_offset(mm
, address
);
1683 if (huge_pmd_unshare(mm
, &address
, ptep
))
1687 * If a reference page is supplied, it is because a specific
1688 * page is being unmapped, not a range. Ensure the page we
1689 * are about to unmap is the actual page of interest.
1692 pte
= huge_ptep_get(ptep
);
1693 if (huge_pte_none(pte
))
1695 page
= pte_page(pte
);
1696 if (page
!= ref_page
)
1700 * Mark the VMA as having unmapped its page so that
1701 * future faults in this VMA will fail rather than
1702 * looking like data was lost
1704 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
1707 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1708 if (huge_pte_none(pte
))
1711 page
= pte_page(pte
);
1713 set_page_dirty(page
);
1714 list_add(&page
->lru
, &page_list
);
1716 spin_unlock(&mm
->page_table_lock
);
1717 flush_tlb_range(vma
, start
, end
);
1718 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1719 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
1720 list_del(&page
->lru
);
1725 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1726 unsigned long end
, struct page
*ref_page
)
1728 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1729 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
1730 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1734 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1735 * mappping it owns the reserve page for. The intention is to unmap the page
1736 * from other VMAs and let the children be SIGKILLed if they are faulting the
1739 int unmap_ref_private(struct mm_struct
*mm
,
1740 struct vm_area_struct
*vma
,
1742 unsigned long address
)
1744 struct vm_area_struct
*iter_vma
;
1745 struct address_space
*mapping
;
1746 struct prio_tree_iter iter
;
1750 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1751 * from page cache lookup which is in HPAGE_SIZE units.
1753 address
= address
& huge_page_mask(hstate_vma(vma
));
1754 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
1755 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
1756 mapping
= (struct address_space
*)page_private(page
);
1758 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1759 /* Do not unmap the current VMA */
1760 if (iter_vma
== vma
)
1764 * Unmap the page from other VMAs without their own reserves.
1765 * They get marked to be SIGKILLed if they fault in these
1766 * areas. This is because a future no-page fault on this VMA
1767 * could insert a zeroed page instead of the data existing
1768 * from the time of fork. This would look like data corruption
1770 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
1771 unmap_hugepage_range(iter_vma
,
1772 address
, address
+ HPAGE_SIZE
,
1779 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1780 unsigned long address
, pte_t
*ptep
, pte_t pte
,
1781 struct page
*pagecache_page
)
1783 struct hstate
*h
= hstate_vma(vma
);
1784 struct page
*old_page
, *new_page
;
1786 int outside_reserve
= 0;
1788 old_page
= pte_page(pte
);
1791 /* If no-one else is actually using this page, avoid the copy
1792 * and just make the page writable */
1793 avoidcopy
= (page_count(old_page
) == 1);
1795 set_huge_ptep_writable(vma
, address
, ptep
);
1800 * If the process that created a MAP_PRIVATE mapping is about to
1801 * perform a COW due to a shared page count, attempt to satisfy
1802 * the allocation without using the existing reserves. The pagecache
1803 * page is used to determine if the reserve at this address was
1804 * consumed or not. If reserves were used, a partial faulted mapping
1805 * at the time of fork() could consume its reserves on COW instead
1806 * of the full address range.
1808 if (!(vma
->vm_flags
& VM_SHARED
) &&
1809 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
1810 old_page
!= pagecache_page
)
1811 outside_reserve
= 1;
1813 page_cache_get(old_page
);
1814 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
1816 if (IS_ERR(new_page
)) {
1817 page_cache_release(old_page
);
1820 * If a process owning a MAP_PRIVATE mapping fails to COW,
1821 * it is due to references held by a child and an insufficient
1822 * huge page pool. To guarantee the original mappers
1823 * reliability, unmap the page from child processes. The child
1824 * may get SIGKILLed if it later faults.
1826 if (outside_reserve
) {
1827 BUG_ON(huge_pte_none(pte
));
1828 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
1829 BUG_ON(page_count(old_page
) != 1);
1830 BUG_ON(huge_pte_none(pte
));
1831 goto retry_avoidcopy
;
1836 return -PTR_ERR(new_page
);
1839 spin_unlock(&mm
->page_table_lock
);
1840 copy_huge_page(new_page
, old_page
, address
, vma
);
1841 __SetPageUptodate(new_page
);
1842 spin_lock(&mm
->page_table_lock
);
1844 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
1845 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
1847 huge_ptep_clear_flush(vma
, address
, ptep
);
1848 set_huge_pte_at(mm
, address
, ptep
,
1849 make_huge_pte(vma
, new_page
, 1));
1850 /* Make the old page be freed below */
1851 new_page
= old_page
;
1853 page_cache_release(new_page
);
1854 page_cache_release(old_page
);
1858 /* Return the pagecache page at a given address within a VMA */
1859 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
1860 struct vm_area_struct
*vma
, unsigned long address
)
1862 struct address_space
*mapping
;
1865 mapping
= vma
->vm_file
->f_mapping
;
1866 idx
= vma_hugecache_offset(h
, vma
, address
);
1868 return find_lock_page(mapping
, idx
);
1871 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1872 unsigned long address
, pte_t
*ptep
, int write_access
)
1874 struct hstate
*h
= hstate_vma(vma
);
1875 int ret
= VM_FAULT_SIGBUS
;
1879 struct address_space
*mapping
;
1883 * Currently, we are forced to kill the process in the event the
1884 * original mapper has unmapped pages from the child due to a failed
1885 * COW. Warn that such a situation has occured as it may not be obvious
1887 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
1889 "PID %d killed due to inadequate hugepage pool\n",
1894 mapping
= vma
->vm_file
->f_mapping
;
1895 idx
= vma_hugecache_offset(h
, vma
, address
);
1898 * Use page lock to guard against racing truncation
1899 * before we get page_table_lock.
1902 page
= find_lock_page(mapping
, idx
);
1904 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1907 page
= alloc_huge_page(vma
, address
, 0);
1909 ret
= -PTR_ERR(page
);
1912 clear_huge_page(page
, address
, huge_page_size(h
));
1913 __SetPageUptodate(page
);
1915 if (vma
->vm_flags
& VM_SHARED
) {
1917 struct inode
*inode
= mapping
->host
;
1919 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
1927 spin_lock(&inode
->i_lock
);
1928 inode
->i_blocks
+= blocks_per_huge_page(h
);
1929 spin_unlock(&inode
->i_lock
);
1934 spin_lock(&mm
->page_table_lock
);
1935 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1940 if (!huge_pte_none(huge_ptep_get(ptep
)))
1943 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
1944 && (vma
->vm_flags
& VM_SHARED
)));
1945 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
1947 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1948 /* Optimization, do the COW without a second fault */
1949 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
1952 spin_unlock(&mm
->page_table_lock
);
1958 spin_unlock(&mm
->page_table_lock
);
1964 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1965 unsigned long address
, int write_access
)
1970 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
1971 struct hstate
*h
= hstate_vma(vma
);
1973 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
1975 return VM_FAULT_OOM
;
1978 * Serialize hugepage allocation and instantiation, so that we don't
1979 * get spurious allocation failures if two CPUs race to instantiate
1980 * the same page in the page cache.
1982 mutex_lock(&hugetlb_instantiation_mutex
);
1983 entry
= huge_ptep_get(ptep
);
1984 if (huge_pte_none(entry
)) {
1985 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
1986 mutex_unlock(&hugetlb_instantiation_mutex
);
1992 spin_lock(&mm
->page_table_lock
);
1993 /* Check for a racing update before calling hugetlb_cow */
1994 if (likely(pte_same(entry
, huge_ptep_get(ptep
))))
1995 if (write_access
&& !pte_write(entry
)) {
1997 page
= hugetlbfs_pagecache_page(h
, vma
, address
);
1998 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
, page
);
2004 spin_unlock(&mm
->page_table_lock
);
2005 mutex_unlock(&hugetlb_instantiation_mutex
);
2010 /* Can be overriden by architectures */
2011 __attribute__((weak
)) struct page
*
2012 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2013 pud_t
*pud
, int write
)
2019 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2020 struct page
**pages
, struct vm_area_struct
**vmas
,
2021 unsigned long *position
, int *length
, int i
,
2024 unsigned long pfn_offset
;
2025 unsigned long vaddr
= *position
;
2026 int remainder
= *length
;
2027 struct hstate
*h
= hstate_vma(vma
);
2029 spin_lock(&mm
->page_table_lock
);
2030 while (vaddr
< vma
->vm_end
&& remainder
) {
2035 * Some archs (sparc64, sh*) have multiple pte_ts to
2036 * each hugepage. We have to make * sure we get the
2037 * first, for the page indexing below to work.
2039 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2041 if (!pte
|| huge_pte_none(huge_ptep_get(pte
)) ||
2042 (write
&& !pte_write(huge_ptep_get(pte
)))) {
2045 spin_unlock(&mm
->page_table_lock
);
2046 ret
= hugetlb_fault(mm
, vma
, vaddr
, write
);
2047 spin_lock(&mm
->page_table_lock
);
2048 if (!(ret
& VM_FAULT_ERROR
))
2057 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2058 page
= pte_page(huge_ptep_get(pte
));
2062 pages
[i
] = page
+ pfn_offset
;
2072 if (vaddr
< vma
->vm_end
&& remainder
&&
2073 pfn_offset
< pages_per_huge_page(h
)) {
2075 * We use pfn_offset to avoid touching the pageframes
2076 * of this compound page.
2081 spin_unlock(&mm
->page_table_lock
);
2082 *length
= remainder
;
2088 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2089 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2091 struct mm_struct
*mm
= vma
->vm_mm
;
2092 unsigned long start
= address
;
2095 struct hstate
*h
= hstate_vma(vma
);
2097 BUG_ON(address
>= end
);
2098 flush_cache_range(vma
, address
, end
);
2100 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2101 spin_lock(&mm
->page_table_lock
);
2102 for (; address
< end
; address
+= huge_page_size(h
)) {
2103 ptep
= huge_pte_offset(mm
, address
);
2106 if (huge_pmd_unshare(mm
, &address
, ptep
))
2108 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2109 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2110 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2111 set_huge_pte_at(mm
, address
, ptep
, pte
);
2114 spin_unlock(&mm
->page_table_lock
);
2115 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2117 flush_tlb_range(vma
, start
, end
);
2120 int hugetlb_reserve_pages(struct inode
*inode
,
2122 struct vm_area_struct
*vma
)
2125 struct hstate
*h
= hstate_inode(inode
);
2127 if (vma
&& vma
->vm_flags
& VM_NORESERVE
)
2131 * Shared mappings base their reservation on the number of pages that
2132 * are already allocated on behalf of the file. Private mappings need
2133 * to reserve the full area even if read-only as mprotect() may be
2134 * called to make the mapping read-write. Assume !vma is a shm mapping
2136 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
2137 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2139 struct resv_map
*resv_map
= resv_map_alloc();
2145 set_vma_resv_map(vma
, resv_map
);
2146 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2152 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2154 ret
= hugetlb_acct_memory(h
, chg
);
2156 hugetlb_put_quota(inode
->i_mapping
, chg
);
2159 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
2160 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2164 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2166 struct hstate
*h
= hstate_inode(inode
);
2167 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2169 spin_lock(&inode
->i_lock
);
2170 inode
->i_blocks
-= blocks_per_huge_page(h
);
2171 spin_unlock(&inode
->i_lock
);
2173 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2174 hugetlb_acct_memory(h
, -(chg
- freed
));