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/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/cpuset.h>
16 #include <linux/mutex.h>
19 #include <asm/pgtable.h>
21 #include <linux/hugetlb.h>
24 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
25 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
26 unsigned long hugepages_treat_as_movable
;
28 static int max_hstate
;
29 unsigned int default_hstate_idx
;
30 struct hstate hstates
[HUGE_MAX_HSTATE
];
32 /* for command line parsing */
33 static struct hstate
* __initdata parsed_hstate
;
34 static unsigned long __initdata default_hstate_max_huge_pages
;
36 #define for_each_hstate(h) \
37 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
40 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
42 static DEFINE_SPINLOCK(hugetlb_lock
);
45 * Region tracking -- allows tracking of reservations and instantiated pages
46 * across the pages in a mapping.
48 * The region data structures are protected by a combination of the mmap_sem
49 * and the hugetlb_instantion_mutex. To access or modify a region the caller
50 * must either hold the mmap_sem for write, or the mmap_sem for read and
51 * the hugetlb_instantiation mutex:
53 * down_write(&mm->mmap_sem);
55 * down_read(&mm->mmap_sem);
56 * mutex_lock(&hugetlb_instantiation_mutex);
59 struct list_head link
;
64 static long region_add(struct list_head
*head
, long f
, long t
)
66 struct file_region
*rg
, *nrg
, *trg
;
68 /* Locate the region we are either in or before. */
69 list_for_each_entry(rg
, head
, link
)
73 /* Round our left edge to the current segment if it encloses us. */
77 /* Check for and consume any regions we now overlap with. */
79 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
80 if (&rg
->link
== head
)
85 /* If this area reaches higher then extend our area to
86 * include it completely. If this is not the first area
87 * which we intend to reuse, free it. */
100 static long region_chg(struct list_head
*head
, long f
, long t
)
102 struct file_region
*rg
, *nrg
;
105 /* Locate the region we are before or in. */
106 list_for_each_entry(rg
, head
, link
)
110 /* If we are below the current region then a new region is required.
111 * Subtle, allocate a new region at the position but make it zero
112 * size such that we can guarantee to record the reservation. */
113 if (&rg
->link
== head
|| t
< rg
->from
) {
114 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
119 INIT_LIST_HEAD(&nrg
->link
);
120 list_add(&nrg
->link
, rg
->link
.prev
);
125 /* Round our left edge to the current segment if it encloses us. */
130 /* Check for and consume any regions we now overlap with. */
131 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
132 if (&rg
->link
== head
)
137 /* We overlap with this area, if it extends futher than
138 * us then we must extend ourselves. Account for its
139 * existing reservation. */
144 chg
-= rg
->to
- rg
->from
;
149 static long region_truncate(struct list_head
*head
, long end
)
151 struct file_region
*rg
, *trg
;
154 /* Locate the region we are either in or before. */
155 list_for_each_entry(rg
, head
, link
)
158 if (&rg
->link
== head
)
161 /* If we are in the middle of a region then adjust it. */
162 if (end
> rg
->from
) {
165 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
168 /* Drop any remaining regions. */
169 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
170 if (&rg
->link
== head
)
172 chg
+= rg
->to
- rg
->from
;
179 static long region_count(struct list_head
*head
, long f
, long t
)
181 struct file_region
*rg
;
184 /* Locate each segment we overlap with, and count that overlap. */
185 list_for_each_entry(rg
, head
, link
) {
194 seg_from
= max(rg
->from
, f
);
195 seg_to
= min(rg
->to
, t
);
197 chg
+= seg_to
- seg_from
;
204 * Convert the address within this vma to the page offset within
205 * the mapping, in pagecache page units; huge pages here.
207 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
208 struct vm_area_struct
*vma
, unsigned long address
)
210 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
211 (vma
->vm_pgoff
>> huge_page_order(h
));
215 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
216 * bits of the reservation map pointer, which are always clear due to
219 #define HPAGE_RESV_OWNER (1UL << 0)
220 #define HPAGE_RESV_UNMAPPED (1UL << 1)
221 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
224 * These helpers are used to track how many pages are reserved for
225 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
226 * is guaranteed to have their future faults succeed.
228 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
229 * the reserve counters are updated with the hugetlb_lock held. It is safe
230 * to reset the VMA at fork() time as it is not in use yet and there is no
231 * chance of the global counters getting corrupted as a result of the values.
233 * The private mapping reservation is represented in a subtly different
234 * manner to a shared mapping. A shared mapping has a region map associated
235 * with the underlying file, this region map represents the backing file
236 * pages which have ever had a reservation assigned which this persists even
237 * after the page is instantiated. A private mapping has a region map
238 * associated with the original mmap which is attached to all VMAs which
239 * reference it, this region map represents those offsets which have consumed
240 * reservation ie. where pages have been instantiated.
242 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
244 return (unsigned long)vma
->vm_private_data
;
247 static void set_vma_private_data(struct vm_area_struct
*vma
,
250 vma
->vm_private_data
= (void *)value
;
255 struct list_head regions
;
258 struct resv_map
*resv_map_alloc(void)
260 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
264 kref_init(&resv_map
->refs
);
265 INIT_LIST_HEAD(&resv_map
->regions
);
270 void resv_map_release(struct kref
*ref
)
272 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
274 /* Clear out any active regions before we release the map. */
275 region_truncate(&resv_map
->regions
, 0);
279 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
281 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
282 if (!(vma
->vm_flags
& VM_SHARED
))
283 return (struct resv_map
*)(get_vma_private_data(vma
) &
288 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
290 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
291 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
293 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
294 HPAGE_RESV_MASK
) | (unsigned long)map
);
297 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
299 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
300 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
302 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
305 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
307 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
309 return (get_vma_private_data(vma
) & flag
) != 0;
312 /* Decrement the reserved pages in the hugepage pool by one */
313 static void decrement_hugepage_resv_vma(struct hstate
*h
,
314 struct vm_area_struct
*vma
)
316 if (vma
->vm_flags
& VM_NORESERVE
)
319 if (vma
->vm_flags
& VM_SHARED
) {
320 /* Shared mappings always use reserves */
321 h
->resv_huge_pages
--;
322 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
324 * Only the process that called mmap() has reserves for
327 h
->resv_huge_pages
--;
331 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
332 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
334 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
335 if (!(vma
->vm_flags
& VM_SHARED
))
336 vma
->vm_private_data
= (void *)0;
339 /* Returns true if the VMA has associated reserve pages */
340 static int vma_has_private_reserves(struct vm_area_struct
*vma
)
342 if (vma
->vm_flags
& VM_SHARED
)
344 if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
349 static void clear_huge_page(struct page
*page
,
350 unsigned long addr
, unsigned long sz
)
355 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
357 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
361 static void copy_huge_page(struct page
*dst
, struct page
*src
,
362 unsigned long addr
, struct vm_area_struct
*vma
)
365 struct hstate
*h
= hstate_vma(vma
);
368 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
370 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
374 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
376 int nid
= page_to_nid(page
);
377 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
378 h
->free_huge_pages
++;
379 h
->free_huge_pages_node
[nid
]++;
382 static struct page
*dequeue_huge_page(struct hstate
*h
)
385 struct page
*page
= NULL
;
387 for (nid
= 0; nid
< MAX_NUMNODES
; ++nid
) {
388 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
389 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
391 list_del(&page
->lru
);
392 h
->free_huge_pages
--;
393 h
->free_huge_pages_node
[nid
]--;
400 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
401 struct vm_area_struct
*vma
,
402 unsigned long address
, int avoid_reserve
)
405 struct page
*page
= NULL
;
406 struct mempolicy
*mpol
;
407 nodemask_t
*nodemask
;
408 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
409 htlb_alloc_mask
, &mpol
, &nodemask
);
414 * A child process with MAP_PRIVATE mappings created by their parent
415 * have no page reserves. This check ensures that reservations are
416 * not "stolen". The child may still get SIGKILLed
418 if (!vma_has_private_reserves(vma
) &&
419 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
422 /* If reserves cannot be used, ensure enough pages are in the pool */
423 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
426 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
427 MAX_NR_ZONES
- 1, nodemask
) {
428 nid
= zone_to_nid(zone
);
429 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
430 !list_empty(&h
->hugepage_freelists
[nid
])) {
431 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
433 list_del(&page
->lru
);
434 h
->free_huge_pages
--;
435 h
->free_huge_pages_node
[nid
]--;
438 decrement_hugepage_resv_vma(h
, vma
);
447 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
452 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
453 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
454 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
455 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
456 1 << PG_private
| 1<< PG_writeback
);
458 set_compound_page_dtor(page
, NULL
);
459 set_page_refcounted(page
);
460 arch_release_hugepage(page
);
461 __free_pages(page
, huge_page_order(h
));
464 struct hstate
*size_to_hstate(unsigned long size
)
469 if (huge_page_size(h
) == size
)
475 static void free_huge_page(struct page
*page
)
478 * Can't pass hstate in here because it is called from the
479 * compound page destructor.
481 struct hstate
*h
= page_hstate(page
);
482 int nid
= page_to_nid(page
);
483 struct address_space
*mapping
;
485 mapping
= (struct address_space
*) page_private(page
);
486 set_page_private(page
, 0);
487 BUG_ON(page_count(page
));
488 INIT_LIST_HEAD(&page
->lru
);
490 spin_lock(&hugetlb_lock
);
491 if (h
->surplus_huge_pages_node
[nid
]) {
492 update_and_free_page(h
, page
);
493 h
->surplus_huge_pages
--;
494 h
->surplus_huge_pages_node
[nid
]--;
496 enqueue_huge_page(h
, page
);
498 spin_unlock(&hugetlb_lock
);
500 hugetlb_put_quota(mapping
, 1);
504 * Increment or decrement surplus_huge_pages. Keep node-specific counters
505 * balanced by operating on them in a round-robin fashion.
506 * Returns 1 if an adjustment was made.
508 static int adjust_pool_surplus(struct hstate
*h
, int delta
)
514 VM_BUG_ON(delta
!= -1 && delta
!= 1);
516 nid
= next_node(nid
, node_online_map
);
517 if (nid
== MAX_NUMNODES
)
518 nid
= first_node(node_online_map
);
520 /* To shrink on this node, there must be a surplus page */
521 if (delta
< 0 && !h
->surplus_huge_pages_node
[nid
])
523 /* Surplus cannot exceed the total number of pages */
524 if (delta
> 0 && h
->surplus_huge_pages_node
[nid
] >=
525 h
->nr_huge_pages_node
[nid
])
528 h
->surplus_huge_pages
+= delta
;
529 h
->surplus_huge_pages_node
[nid
] += delta
;
532 } while (nid
!= prev_nid
);
538 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
540 set_compound_page_dtor(page
, free_huge_page
);
541 spin_lock(&hugetlb_lock
);
543 h
->nr_huge_pages_node
[nid
]++;
544 spin_unlock(&hugetlb_lock
);
545 put_page(page
); /* free it into the hugepage allocator */
548 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
552 page
= alloc_pages_node(nid
,
553 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
554 __GFP_REPEAT
|__GFP_NOWARN
,
557 if (arch_prepare_hugepage(page
)) {
558 __free_pages(page
, HUGETLB_PAGE_ORDER
);
561 prep_new_huge_page(h
, page
, nid
);
567 static int alloc_fresh_huge_page(struct hstate
*h
)
574 start_nid
= h
->hugetlb_next_nid
;
577 page
= alloc_fresh_huge_page_node(h
, h
->hugetlb_next_nid
);
581 * Use a helper variable to find the next node and then
582 * copy it back to hugetlb_next_nid afterwards:
583 * otherwise there's a window in which a racer might
584 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
585 * But we don't need to use a spin_lock here: it really
586 * doesn't matter if occasionally a racer chooses the
587 * same nid as we do. Move nid forward in the mask even
588 * if we just successfully allocated a hugepage so that
589 * the next caller gets hugepages on the next node.
591 next_nid
= next_node(h
->hugetlb_next_nid
, node_online_map
);
592 if (next_nid
== MAX_NUMNODES
)
593 next_nid
= first_node(node_online_map
);
594 h
->hugetlb_next_nid
= next_nid
;
595 } while (!page
&& h
->hugetlb_next_nid
!= start_nid
);
598 count_vm_event(HTLB_BUDDY_PGALLOC
);
600 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
605 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
606 struct vm_area_struct
*vma
, unsigned long address
)
612 * Assume we will successfully allocate the surplus page to
613 * prevent racing processes from causing the surplus to exceed
616 * This however introduces a different race, where a process B
617 * tries to grow the static hugepage pool while alloc_pages() is
618 * called by process A. B will only examine the per-node
619 * counters in determining if surplus huge pages can be
620 * converted to normal huge pages in adjust_pool_surplus(). A
621 * won't be able to increment the per-node counter, until the
622 * lock is dropped by B, but B doesn't drop hugetlb_lock until
623 * no more huge pages can be converted from surplus to normal
624 * state (and doesn't try to convert again). Thus, we have a
625 * case where a surplus huge page exists, the pool is grown, and
626 * the surplus huge page still exists after, even though it
627 * should just have been converted to a normal huge page. This
628 * does not leak memory, though, as the hugepage will be freed
629 * once it is out of use. It also does not allow the counters to
630 * go out of whack in adjust_pool_surplus() as we don't modify
631 * the node values until we've gotten the hugepage and only the
632 * per-node value is checked there.
634 spin_lock(&hugetlb_lock
);
635 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
636 spin_unlock(&hugetlb_lock
);
640 h
->surplus_huge_pages
++;
642 spin_unlock(&hugetlb_lock
);
644 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
645 __GFP_REPEAT
|__GFP_NOWARN
,
648 spin_lock(&hugetlb_lock
);
651 * This page is now managed by the hugetlb allocator and has
652 * no users -- drop the buddy allocator's reference.
654 put_page_testzero(page
);
655 VM_BUG_ON(page_count(page
));
656 nid
= page_to_nid(page
);
657 set_compound_page_dtor(page
, free_huge_page
);
659 * We incremented the global counters already
661 h
->nr_huge_pages_node
[nid
]++;
662 h
->surplus_huge_pages_node
[nid
]++;
663 __count_vm_event(HTLB_BUDDY_PGALLOC
);
666 h
->surplus_huge_pages
--;
667 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
669 spin_unlock(&hugetlb_lock
);
675 * Increase the hugetlb pool such that it can accomodate a reservation
678 static int gather_surplus_pages(struct hstate
*h
, int delta
)
680 struct list_head surplus_list
;
681 struct page
*page
, *tmp
;
683 int needed
, allocated
;
685 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
687 h
->resv_huge_pages
+= delta
;
692 INIT_LIST_HEAD(&surplus_list
);
696 spin_unlock(&hugetlb_lock
);
697 for (i
= 0; i
< needed
; i
++) {
698 page
= alloc_buddy_huge_page(h
, NULL
, 0);
701 * We were not able to allocate enough pages to
702 * satisfy the entire reservation so we free what
703 * we've allocated so far.
705 spin_lock(&hugetlb_lock
);
710 list_add(&page
->lru
, &surplus_list
);
715 * After retaking hugetlb_lock, we need to recalculate 'needed'
716 * because either resv_huge_pages or free_huge_pages may have changed.
718 spin_lock(&hugetlb_lock
);
719 needed
= (h
->resv_huge_pages
+ delta
) -
720 (h
->free_huge_pages
+ allocated
);
725 * The surplus_list now contains _at_least_ the number of extra pages
726 * needed to accomodate the reservation. Add the appropriate number
727 * of pages to the hugetlb pool and free the extras back to the buddy
728 * allocator. Commit the entire reservation here to prevent another
729 * process from stealing the pages as they are added to the pool but
730 * before they are reserved.
733 h
->resv_huge_pages
+= delta
;
736 /* Free the needed pages to the hugetlb pool */
737 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
740 list_del(&page
->lru
);
741 enqueue_huge_page(h
, page
);
744 /* Free unnecessary surplus pages to the buddy allocator */
745 if (!list_empty(&surplus_list
)) {
746 spin_unlock(&hugetlb_lock
);
747 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
748 list_del(&page
->lru
);
750 * The page has a reference count of zero already, so
751 * call free_huge_page directly instead of using
752 * put_page. This must be done with hugetlb_lock
753 * unlocked which is safe because free_huge_page takes
754 * hugetlb_lock before deciding how to free the page.
756 free_huge_page(page
);
758 spin_lock(&hugetlb_lock
);
765 * When releasing a hugetlb pool reservation, any surplus pages that were
766 * allocated to satisfy the reservation must be explicitly freed if they were
769 static void return_unused_surplus_pages(struct hstate
*h
,
770 unsigned long unused_resv_pages
)
774 unsigned long nr_pages
;
777 * We want to release as many surplus pages as possible, spread
778 * evenly across all nodes. Iterate across all nodes until we
779 * can no longer free unreserved surplus pages. This occurs when
780 * the nodes with surplus pages have no free pages.
782 unsigned long remaining_iterations
= num_online_nodes();
784 /* Uncommit the reservation */
785 h
->resv_huge_pages
-= unused_resv_pages
;
787 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
789 while (remaining_iterations
-- && nr_pages
) {
790 nid
= next_node(nid
, node_online_map
);
791 if (nid
== MAX_NUMNODES
)
792 nid
= first_node(node_online_map
);
794 if (!h
->surplus_huge_pages_node
[nid
])
797 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
798 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
800 list_del(&page
->lru
);
801 update_and_free_page(h
, page
);
802 h
->free_huge_pages
--;
803 h
->free_huge_pages_node
[nid
]--;
804 h
->surplus_huge_pages
--;
805 h
->surplus_huge_pages_node
[nid
]--;
807 remaining_iterations
= num_online_nodes();
813 * Determine if the huge page at addr within the vma has an associated
814 * reservation. Where it does not we will need to logically increase
815 * reservation and actually increase quota before an allocation can occur.
816 * Where any new reservation would be required the reservation change is
817 * prepared, but not committed. Once the page has been quota'd allocated
818 * an instantiated the change should be committed via vma_commit_reservation.
819 * No action is required on failure.
821 static int vma_needs_reservation(struct hstate
*h
,
822 struct vm_area_struct
*vma
, unsigned long addr
)
824 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
825 struct inode
*inode
= mapping
->host
;
827 if (vma
->vm_flags
& VM_SHARED
) {
828 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
829 return region_chg(&inode
->i_mapping
->private_list
,
832 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
837 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
838 struct resv_map
*reservations
= vma_resv_map(vma
);
840 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
846 static void vma_commit_reservation(struct hstate
*h
,
847 struct vm_area_struct
*vma
, unsigned long addr
)
849 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
850 struct inode
*inode
= mapping
->host
;
852 if (vma
->vm_flags
& VM_SHARED
) {
853 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
854 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
856 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
857 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
858 struct resv_map
*reservations
= vma_resv_map(vma
);
860 /* Mark this page used in the map. */
861 region_add(&reservations
->regions
, idx
, idx
+ 1);
865 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
866 unsigned long addr
, int avoid_reserve
)
868 struct hstate
*h
= hstate_vma(vma
);
870 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
871 struct inode
*inode
= mapping
->host
;
875 * Processes that did not create the mapping will have no reserves and
876 * will not have accounted against quota. Check that the quota can be
877 * made before satisfying the allocation
878 * MAP_NORESERVE mappings may also need pages and quota allocated
879 * if no reserve mapping overlaps.
881 chg
= vma_needs_reservation(h
, vma
, addr
);
885 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
886 return ERR_PTR(-ENOSPC
);
888 spin_lock(&hugetlb_lock
);
889 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
890 spin_unlock(&hugetlb_lock
);
893 page
= alloc_buddy_huge_page(h
, vma
, addr
);
895 hugetlb_put_quota(inode
->i_mapping
, chg
);
896 return ERR_PTR(-VM_FAULT_OOM
);
900 set_page_refcounted(page
);
901 set_page_private(page
, (unsigned long) mapping
);
903 vma_commit_reservation(h
, vma
, addr
);
908 static void __init
hugetlb_init_one_hstate(struct hstate
*h
)
912 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
913 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
915 h
->hugetlb_next_nid
= first_node(node_online_map
);
917 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
918 if (!alloc_fresh_huge_page(h
))
921 h
->max_huge_pages
= h
->free_huge_pages
= h
->nr_huge_pages
= i
;
924 static void __init
hugetlb_init_hstates(void)
929 hugetlb_init_one_hstate(h
);
933 static void __init
report_hugepages(void)
938 printk(KERN_INFO
"Total HugeTLB memory allocated, "
941 1 << (h
->order
+ PAGE_SHIFT
- 20));
945 static int __init
hugetlb_init(void)
947 BUILD_BUG_ON(HPAGE_SHIFT
== 0);
949 if (!size_to_hstate(HPAGE_SIZE
)) {
950 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
951 parsed_hstate
->max_huge_pages
= default_hstate_max_huge_pages
;
953 default_hstate_idx
= size_to_hstate(HPAGE_SIZE
) - hstates
;
955 hugetlb_init_hstates();
961 module_init(hugetlb_init
);
963 /* Should be called on processing a hugepagesz=... option */
964 void __init
hugetlb_add_hstate(unsigned order
)
967 if (size_to_hstate(PAGE_SIZE
<< order
)) {
968 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
971 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
973 h
= &hstates
[max_hstate
++];
975 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
976 hugetlb_init_one_hstate(h
);
980 static int __init
hugetlb_setup(char *s
)
985 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
986 * so this hugepages= parameter goes to the "default hstate".
989 mhp
= &default_hstate_max_huge_pages
;
991 mhp
= &parsed_hstate
->max_huge_pages
;
993 if (sscanf(s
, "%lu", mhp
) <= 0)
998 __setup("hugepages=", hugetlb_setup
);
1000 static unsigned int cpuset_mems_nr(unsigned int *array
)
1003 unsigned int nr
= 0;
1005 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1011 #ifdef CONFIG_SYSCTL
1012 #ifdef CONFIG_HIGHMEM
1013 static void try_to_free_low(struct hstate
*h
, unsigned long count
)
1017 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
1018 struct page
*page
, *next
;
1019 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1020 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1021 if (count
>= h
->nr_huge_pages
)
1023 if (PageHighMem(page
))
1025 list_del(&page
->lru
);
1026 update_and_free_page(h
, page
);
1027 h
->free_huge_pages
--;
1028 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1033 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
)
1038 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1039 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
)
1041 unsigned long min_count
, ret
;
1044 * Increase the pool size
1045 * First take pages out of surplus state. Then make up the
1046 * remaining difference by allocating fresh huge pages.
1048 * We might race with alloc_buddy_huge_page() here and be unable
1049 * to convert a surplus huge page to a normal huge page. That is
1050 * not critical, though, it just means the overall size of the
1051 * pool might be one hugepage larger than it needs to be, but
1052 * within all the constraints specified by the sysctls.
1054 spin_lock(&hugetlb_lock
);
1055 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1056 if (!adjust_pool_surplus(h
, -1))
1060 while (count
> persistent_huge_pages(h
)) {
1062 * If this allocation races such that we no longer need the
1063 * page, free_huge_page will handle it by freeing the page
1064 * and reducing the surplus.
1066 spin_unlock(&hugetlb_lock
);
1067 ret
= alloc_fresh_huge_page(h
);
1068 spin_lock(&hugetlb_lock
);
1075 * Decrease the pool size
1076 * First return free pages to the buddy allocator (being careful
1077 * to keep enough around to satisfy reservations). Then place
1078 * pages into surplus state as needed so the pool will shrink
1079 * to the desired size as pages become free.
1081 * By placing pages into the surplus state independent of the
1082 * overcommit value, we are allowing the surplus pool size to
1083 * exceed overcommit. There are few sane options here. Since
1084 * alloc_buddy_huge_page() is checking the global counter,
1085 * though, we'll note that we're not allowed to exceed surplus
1086 * and won't grow the pool anywhere else. Not until one of the
1087 * sysctls are changed, or the surplus pages go out of use.
1089 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1090 min_count
= max(count
, min_count
);
1091 try_to_free_low(h
, min_count
);
1092 while (min_count
< persistent_huge_pages(h
)) {
1093 struct page
*page
= dequeue_huge_page(h
);
1096 update_and_free_page(h
, page
);
1098 while (count
< persistent_huge_pages(h
)) {
1099 if (!adjust_pool_surplus(h
, 1))
1103 ret
= persistent_huge_pages(h
);
1104 spin_unlock(&hugetlb_lock
);
1108 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1109 struct file
*file
, void __user
*buffer
,
1110 size_t *length
, loff_t
*ppos
)
1112 struct hstate
*h
= &default_hstate
;
1116 tmp
= h
->max_huge_pages
;
1119 table
->maxlen
= sizeof(unsigned long);
1120 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1123 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
);
1128 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1129 struct file
*file
, void __user
*buffer
,
1130 size_t *length
, loff_t
*ppos
)
1132 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
1133 if (hugepages_treat_as_movable
)
1134 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1136 htlb_alloc_mask
= GFP_HIGHUSER
;
1140 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1141 struct file
*file
, void __user
*buffer
,
1142 size_t *length
, loff_t
*ppos
)
1144 struct hstate
*h
= &default_hstate
;
1148 tmp
= h
->nr_overcommit_huge_pages
;
1151 table
->maxlen
= sizeof(unsigned long);
1152 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1155 spin_lock(&hugetlb_lock
);
1156 h
->nr_overcommit_huge_pages
= tmp
;
1157 spin_unlock(&hugetlb_lock
);
1163 #endif /* CONFIG_SYSCTL */
1165 int hugetlb_report_meminfo(char *buf
)
1167 struct hstate
*h
= &default_hstate
;
1169 "HugePages_Total: %5lu\n"
1170 "HugePages_Free: %5lu\n"
1171 "HugePages_Rsvd: %5lu\n"
1172 "HugePages_Surp: %5lu\n"
1173 "Hugepagesize: %5lu kB\n",
1177 h
->surplus_huge_pages
,
1178 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1181 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1183 struct hstate
*h
= &default_hstate
;
1185 "Node %d HugePages_Total: %5u\n"
1186 "Node %d HugePages_Free: %5u\n"
1187 "Node %d HugePages_Surp: %5u\n",
1188 nid
, h
->nr_huge_pages_node
[nid
],
1189 nid
, h
->free_huge_pages_node
[nid
],
1190 nid
, h
->surplus_huge_pages_node
[nid
]);
1193 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1194 unsigned long hugetlb_total_pages(void)
1196 struct hstate
*h
= &default_hstate
;
1197 return h
->nr_huge_pages
* pages_per_huge_page(h
);
1200 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
1204 spin_lock(&hugetlb_lock
);
1206 * When cpuset is configured, it breaks the strict hugetlb page
1207 * reservation as the accounting is done on a global variable. Such
1208 * reservation is completely rubbish in the presence of cpuset because
1209 * the reservation is not checked against page availability for the
1210 * current cpuset. Application can still potentially OOM'ed by kernel
1211 * with lack of free htlb page in cpuset that the task is in.
1212 * Attempt to enforce strict accounting with cpuset is almost
1213 * impossible (or too ugly) because cpuset is too fluid that
1214 * task or memory node can be dynamically moved between cpusets.
1216 * The change of semantics for shared hugetlb mapping with cpuset is
1217 * undesirable. However, in order to preserve some of the semantics,
1218 * we fall back to check against current free page availability as
1219 * a best attempt and hopefully to minimize the impact of changing
1220 * semantics that cpuset has.
1223 if (gather_surplus_pages(h
, delta
) < 0)
1226 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
1227 return_unused_surplus_pages(h
, delta
);
1234 return_unused_surplus_pages(h
, (unsigned long) -delta
);
1237 spin_unlock(&hugetlb_lock
);
1241 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
1243 struct resv_map
*reservations
= vma_resv_map(vma
);
1246 * This new VMA should share its siblings reservation map if present.
1247 * The VMA will only ever have a valid reservation map pointer where
1248 * it is being copied for another still existing VMA. As that VMA
1249 * has a reference to the reservation map it cannot dissappear until
1250 * after this open call completes. It is therefore safe to take a
1251 * new reference here without additional locking.
1254 kref_get(&reservations
->refs
);
1257 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
1259 struct hstate
*h
= hstate_vma(vma
);
1260 struct resv_map
*reservations
= vma_resv_map(vma
);
1261 unsigned long reserve
;
1262 unsigned long start
;
1266 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
1267 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
1269 reserve
= (end
- start
) -
1270 region_count(&reservations
->regions
, start
, end
);
1272 kref_put(&reservations
->refs
, resv_map_release
);
1275 hugetlb_acct_memory(h
, -reserve
);
1280 * We cannot handle pagefaults against hugetlb pages at all. They cause
1281 * handle_mm_fault() to try to instantiate regular-sized pages in the
1282 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1285 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1291 struct vm_operations_struct hugetlb_vm_ops
= {
1292 .fault
= hugetlb_vm_op_fault
,
1293 .open
= hugetlb_vm_op_open
,
1294 .close
= hugetlb_vm_op_close
,
1297 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
1304 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
1306 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
1308 entry
= pte_mkyoung(entry
);
1309 entry
= pte_mkhuge(entry
);
1314 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
1315 unsigned long address
, pte_t
*ptep
)
1319 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
1320 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
1321 update_mmu_cache(vma
, address
, entry
);
1326 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
1327 struct vm_area_struct
*vma
)
1329 pte_t
*src_pte
, *dst_pte
, entry
;
1330 struct page
*ptepage
;
1333 struct hstate
*h
= hstate_vma(vma
);
1334 unsigned long sz
= huge_page_size(h
);
1336 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
1338 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
1339 src_pte
= huge_pte_offset(src
, addr
);
1342 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
1346 /* If the pagetables are shared don't copy or take references */
1347 if (dst_pte
== src_pte
)
1350 spin_lock(&dst
->page_table_lock
);
1351 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
1352 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
1354 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
1355 entry
= huge_ptep_get(src_pte
);
1356 ptepage
= pte_page(entry
);
1358 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
1360 spin_unlock(&src
->page_table_lock
);
1361 spin_unlock(&dst
->page_table_lock
);
1369 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1370 unsigned long end
, struct page
*ref_page
)
1372 struct mm_struct
*mm
= vma
->vm_mm
;
1373 unsigned long address
;
1378 struct hstate
*h
= hstate_vma(vma
);
1379 unsigned long sz
= huge_page_size(h
);
1382 * A page gathering list, protected by per file i_mmap_lock. The
1383 * lock is used to avoid list corruption from multiple unmapping
1384 * of the same page since we are using page->lru.
1386 LIST_HEAD(page_list
);
1388 WARN_ON(!is_vm_hugetlb_page(vma
));
1389 BUG_ON(start
& ~huge_page_mask(h
));
1390 BUG_ON(end
& ~huge_page_mask(h
));
1392 spin_lock(&mm
->page_table_lock
);
1393 for (address
= start
; address
< end
; address
+= sz
) {
1394 ptep
= huge_pte_offset(mm
, address
);
1398 if (huge_pmd_unshare(mm
, &address
, ptep
))
1402 * If a reference page is supplied, it is because a specific
1403 * page is being unmapped, not a range. Ensure the page we
1404 * are about to unmap is the actual page of interest.
1407 pte
= huge_ptep_get(ptep
);
1408 if (huge_pte_none(pte
))
1410 page
= pte_page(pte
);
1411 if (page
!= ref_page
)
1415 * Mark the VMA as having unmapped its page so that
1416 * future faults in this VMA will fail rather than
1417 * looking like data was lost
1419 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
1422 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1423 if (huge_pte_none(pte
))
1426 page
= pte_page(pte
);
1428 set_page_dirty(page
);
1429 list_add(&page
->lru
, &page_list
);
1431 spin_unlock(&mm
->page_table_lock
);
1432 flush_tlb_range(vma
, start
, end
);
1433 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
1434 list_del(&page
->lru
);
1439 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1440 unsigned long end
, struct page
*ref_page
)
1442 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1443 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
1444 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1448 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1449 * mappping it owns the reserve page for. The intention is to unmap the page
1450 * from other VMAs and let the children be SIGKILLed if they are faulting the
1453 int unmap_ref_private(struct mm_struct
*mm
,
1454 struct vm_area_struct
*vma
,
1456 unsigned long address
)
1458 struct vm_area_struct
*iter_vma
;
1459 struct address_space
*mapping
;
1460 struct prio_tree_iter iter
;
1464 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1465 * from page cache lookup which is in HPAGE_SIZE units.
1467 address
= address
& huge_page_mask(hstate_vma(vma
));
1468 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
1469 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
1470 mapping
= (struct address_space
*)page_private(page
);
1472 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1473 /* Do not unmap the current VMA */
1474 if (iter_vma
== vma
)
1478 * Unmap the page from other VMAs without their own reserves.
1479 * They get marked to be SIGKILLed if they fault in these
1480 * areas. This is because a future no-page fault on this VMA
1481 * could insert a zeroed page instead of the data existing
1482 * from the time of fork. This would look like data corruption
1484 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
1485 unmap_hugepage_range(iter_vma
,
1486 address
, address
+ HPAGE_SIZE
,
1493 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1494 unsigned long address
, pte_t
*ptep
, pte_t pte
,
1495 struct page
*pagecache_page
)
1497 struct hstate
*h
= hstate_vma(vma
);
1498 struct page
*old_page
, *new_page
;
1500 int outside_reserve
= 0;
1502 old_page
= pte_page(pte
);
1505 /* If no-one else is actually using this page, avoid the copy
1506 * and just make the page writable */
1507 avoidcopy
= (page_count(old_page
) == 1);
1509 set_huge_ptep_writable(vma
, address
, ptep
);
1514 * If the process that created a MAP_PRIVATE mapping is about to
1515 * perform a COW due to a shared page count, attempt to satisfy
1516 * the allocation without using the existing reserves. The pagecache
1517 * page is used to determine if the reserve at this address was
1518 * consumed or not. If reserves were used, a partial faulted mapping
1519 * at the time of fork() could consume its reserves on COW instead
1520 * of the full address range.
1522 if (!(vma
->vm_flags
& VM_SHARED
) &&
1523 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
1524 old_page
!= pagecache_page
)
1525 outside_reserve
= 1;
1527 page_cache_get(old_page
);
1528 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
1530 if (IS_ERR(new_page
)) {
1531 page_cache_release(old_page
);
1534 * If a process owning a MAP_PRIVATE mapping fails to COW,
1535 * it is due to references held by a child and an insufficient
1536 * huge page pool. To guarantee the original mappers
1537 * reliability, unmap the page from child processes. The child
1538 * may get SIGKILLed if it later faults.
1540 if (outside_reserve
) {
1541 BUG_ON(huge_pte_none(pte
));
1542 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
1543 BUG_ON(page_count(old_page
) != 1);
1544 BUG_ON(huge_pte_none(pte
));
1545 goto retry_avoidcopy
;
1550 return -PTR_ERR(new_page
);
1553 spin_unlock(&mm
->page_table_lock
);
1554 copy_huge_page(new_page
, old_page
, address
, vma
);
1555 __SetPageUptodate(new_page
);
1556 spin_lock(&mm
->page_table_lock
);
1558 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
1559 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
1561 huge_ptep_clear_flush(vma
, address
, ptep
);
1562 set_huge_pte_at(mm
, address
, ptep
,
1563 make_huge_pte(vma
, new_page
, 1));
1564 /* Make the old page be freed below */
1565 new_page
= old_page
;
1567 page_cache_release(new_page
);
1568 page_cache_release(old_page
);
1572 /* Return the pagecache page at a given address within a VMA */
1573 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
1574 struct vm_area_struct
*vma
, unsigned long address
)
1576 struct address_space
*mapping
;
1579 mapping
= vma
->vm_file
->f_mapping
;
1580 idx
= vma_hugecache_offset(h
, vma
, address
);
1582 return find_lock_page(mapping
, idx
);
1585 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1586 unsigned long address
, pte_t
*ptep
, int write_access
)
1588 struct hstate
*h
= hstate_vma(vma
);
1589 int ret
= VM_FAULT_SIGBUS
;
1593 struct address_space
*mapping
;
1597 * Currently, we are forced to kill the process in the event the
1598 * original mapper has unmapped pages from the child due to a failed
1599 * COW. Warn that such a situation has occured as it may not be obvious
1601 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
1603 "PID %d killed due to inadequate hugepage pool\n",
1608 mapping
= vma
->vm_file
->f_mapping
;
1609 idx
= vma_hugecache_offset(h
, vma
, address
);
1612 * Use page lock to guard against racing truncation
1613 * before we get page_table_lock.
1616 page
= find_lock_page(mapping
, idx
);
1618 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1621 page
= alloc_huge_page(vma
, address
, 0);
1623 ret
= -PTR_ERR(page
);
1626 clear_huge_page(page
, address
, huge_page_size(h
));
1627 __SetPageUptodate(page
);
1629 if (vma
->vm_flags
& VM_SHARED
) {
1631 struct inode
*inode
= mapping
->host
;
1633 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
1641 spin_lock(&inode
->i_lock
);
1642 inode
->i_blocks
+= blocks_per_huge_page(h
);
1643 spin_unlock(&inode
->i_lock
);
1648 spin_lock(&mm
->page_table_lock
);
1649 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1654 if (!huge_pte_none(huge_ptep_get(ptep
)))
1657 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
1658 && (vma
->vm_flags
& VM_SHARED
)));
1659 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
1661 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1662 /* Optimization, do the COW without a second fault */
1663 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
1666 spin_unlock(&mm
->page_table_lock
);
1672 spin_unlock(&mm
->page_table_lock
);
1678 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1679 unsigned long address
, int write_access
)
1684 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
1685 struct hstate
*h
= hstate_vma(vma
);
1687 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
1689 return VM_FAULT_OOM
;
1692 * Serialize hugepage allocation and instantiation, so that we don't
1693 * get spurious allocation failures if two CPUs race to instantiate
1694 * the same page in the page cache.
1696 mutex_lock(&hugetlb_instantiation_mutex
);
1697 entry
= huge_ptep_get(ptep
);
1698 if (huge_pte_none(entry
)) {
1699 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
1700 mutex_unlock(&hugetlb_instantiation_mutex
);
1706 spin_lock(&mm
->page_table_lock
);
1707 /* Check for a racing update before calling hugetlb_cow */
1708 if (likely(pte_same(entry
, huge_ptep_get(ptep
))))
1709 if (write_access
&& !pte_write(entry
)) {
1711 page
= hugetlbfs_pagecache_page(h
, vma
, address
);
1712 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
, page
);
1718 spin_unlock(&mm
->page_table_lock
);
1719 mutex_unlock(&hugetlb_instantiation_mutex
);
1724 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1725 struct page
**pages
, struct vm_area_struct
**vmas
,
1726 unsigned long *position
, int *length
, int i
,
1729 unsigned long pfn_offset
;
1730 unsigned long vaddr
= *position
;
1731 int remainder
= *length
;
1732 struct hstate
*h
= hstate_vma(vma
);
1734 spin_lock(&mm
->page_table_lock
);
1735 while (vaddr
< vma
->vm_end
&& remainder
) {
1740 * Some archs (sparc64, sh*) have multiple pte_ts to
1741 * each hugepage. We have to make * sure we get the
1742 * first, for the page indexing below to work.
1744 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
1746 if (!pte
|| huge_pte_none(huge_ptep_get(pte
)) ||
1747 (write
&& !pte_write(huge_ptep_get(pte
)))) {
1750 spin_unlock(&mm
->page_table_lock
);
1751 ret
= hugetlb_fault(mm
, vma
, vaddr
, write
);
1752 spin_lock(&mm
->page_table_lock
);
1753 if (!(ret
& VM_FAULT_ERROR
))
1762 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
1763 page
= pte_page(huge_ptep_get(pte
));
1767 pages
[i
] = page
+ pfn_offset
;
1777 if (vaddr
< vma
->vm_end
&& remainder
&&
1778 pfn_offset
< pages_per_huge_page(h
)) {
1780 * We use pfn_offset to avoid touching the pageframes
1781 * of this compound page.
1786 spin_unlock(&mm
->page_table_lock
);
1787 *length
= remainder
;
1793 void hugetlb_change_protection(struct vm_area_struct
*vma
,
1794 unsigned long address
, unsigned long end
, pgprot_t newprot
)
1796 struct mm_struct
*mm
= vma
->vm_mm
;
1797 unsigned long start
= address
;
1800 struct hstate
*h
= hstate_vma(vma
);
1802 BUG_ON(address
>= end
);
1803 flush_cache_range(vma
, address
, end
);
1805 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1806 spin_lock(&mm
->page_table_lock
);
1807 for (; address
< end
; address
+= huge_page_size(h
)) {
1808 ptep
= huge_pte_offset(mm
, address
);
1811 if (huge_pmd_unshare(mm
, &address
, ptep
))
1813 if (!huge_pte_none(huge_ptep_get(ptep
))) {
1814 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1815 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
1816 set_huge_pte_at(mm
, address
, ptep
, pte
);
1819 spin_unlock(&mm
->page_table_lock
);
1820 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1822 flush_tlb_range(vma
, start
, end
);
1825 int hugetlb_reserve_pages(struct inode
*inode
,
1827 struct vm_area_struct
*vma
)
1830 struct hstate
*h
= hstate_inode(inode
);
1832 if (vma
&& vma
->vm_flags
& VM_NORESERVE
)
1836 * Shared mappings base their reservation on the number of pages that
1837 * are already allocated on behalf of the file. Private mappings need
1838 * to reserve the full area even if read-only as mprotect() may be
1839 * called to make the mapping read-write. Assume !vma is a shm mapping
1841 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
1842 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
1844 struct resv_map
*resv_map
= resv_map_alloc();
1850 set_vma_resv_map(vma
, resv_map
);
1851 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
1857 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1859 ret
= hugetlb_acct_memory(h
, chg
);
1861 hugetlb_put_quota(inode
->i_mapping
, chg
);
1864 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
1865 region_add(&inode
->i_mapping
->private_list
, from
, to
);
1869 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
1871 struct hstate
*h
= hstate_inode(inode
);
1872 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
1874 spin_lock(&inode
->i_lock
);
1875 inode
->i_blocks
-= blocks_per_huge_page(h
);
1876 spin_unlock(&inode
->i_lock
);
1878 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
1879 hugetlb_acct_memory(h
, -(chg
- freed
));