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 unsigned long nr_huge_pages
, free_huge_pages
, resv_huge_pages
;
26 static unsigned long surplus_huge_pages
;
27 static unsigned long nr_overcommit_huge_pages
;
28 unsigned long max_huge_pages
;
29 unsigned long sysctl_overcommit_huge_pages
;
30 static struct list_head hugepage_freelists
[MAX_NUMNODES
];
31 static unsigned int nr_huge_pages_node
[MAX_NUMNODES
];
32 static unsigned int free_huge_pages_node
[MAX_NUMNODES
];
33 static unsigned int surplus_huge_pages_node
[MAX_NUMNODES
];
34 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
35 unsigned long hugepages_treat_as_movable
;
36 static int hugetlb_next_nid
;
39 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
41 static DEFINE_SPINLOCK(hugetlb_lock
);
44 * Region tracking -- allows tracking of reservations and instantiated pages
45 * across the pages in a mapping.
47 * The region data structures are protected by a combination of the mmap_sem
48 * and the hugetlb_instantion_mutex. To access or modify a region the caller
49 * must either hold the mmap_sem for write, or the mmap_sem for read and
50 * the hugetlb_instantiation mutex:
52 * down_write(&mm->mmap_sem);
54 * down_read(&mm->mmap_sem);
55 * mutex_lock(&hugetlb_instantiation_mutex);
58 struct list_head link
;
63 static long region_add(struct list_head
*head
, long f
, long t
)
65 struct file_region
*rg
, *nrg
, *trg
;
67 /* Locate the region we are either in or before. */
68 list_for_each_entry(rg
, head
, link
)
72 /* Round our left edge to the current segment if it encloses us. */
76 /* Check for and consume any regions we now overlap with. */
78 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
79 if (&rg
->link
== head
)
84 /* If this area reaches higher then extend our area to
85 * include it completely. If this is not the first area
86 * which we intend to reuse, free it. */
99 static long region_chg(struct list_head
*head
, long f
, long t
)
101 struct file_region
*rg
, *nrg
;
104 /* Locate the region we are before or in. */
105 list_for_each_entry(rg
, head
, link
)
109 /* If we are below the current region then a new region is required.
110 * Subtle, allocate a new region at the position but make it zero
111 * size such that we can guarantee to record the reservation. */
112 if (&rg
->link
== head
|| t
< rg
->from
) {
113 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
118 INIT_LIST_HEAD(&nrg
->link
);
119 list_add(&nrg
->link
, rg
->link
.prev
);
124 /* Round our left edge to the current segment if it encloses us. */
129 /* Check for and consume any regions we now overlap with. */
130 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
131 if (&rg
->link
== head
)
136 /* We overlap with this area, if it extends futher than
137 * us then we must extend ourselves. Account for its
138 * existing reservation. */
143 chg
-= rg
->to
- rg
->from
;
148 static long region_truncate(struct list_head
*head
, long end
)
150 struct file_region
*rg
, *trg
;
153 /* Locate the region we are either in or before. */
154 list_for_each_entry(rg
, head
, link
)
157 if (&rg
->link
== head
)
160 /* If we are in the middle of a region then adjust it. */
161 if (end
> rg
->from
) {
164 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
167 /* Drop any remaining regions. */
168 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
169 if (&rg
->link
== head
)
171 chg
+= rg
->to
- rg
->from
;
178 static long region_count(struct list_head
*head
, long f
, long t
)
180 struct file_region
*rg
;
183 /* Locate each segment we overlap with, and count that overlap. */
184 list_for_each_entry(rg
, head
, link
) {
193 seg_from
= max(rg
->from
, f
);
194 seg_to
= min(rg
->to
, t
);
196 chg
+= seg_to
- seg_from
;
203 * Convert the address within this vma to the page offset within
204 * the mapping, in pagecache page units; huge pages here.
206 static pgoff_t
vma_hugecache_offset(struct vm_area_struct
*vma
,
207 unsigned long address
)
209 return ((address
- vma
->vm_start
) >> HPAGE_SHIFT
) +
210 (vma
->vm_pgoff
>> (HPAGE_SHIFT
- PAGE_SHIFT
));
214 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
215 * bits of the reservation map pointer, which are always clear due to
218 #define HPAGE_RESV_OWNER (1UL << 0)
219 #define HPAGE_RESV_UNMAPPED (1UL << 1)
220 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
223 * These helpers are used to track how many pages are reserved for
224 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
225 * is guaranteed to have their future faults succeed.
227 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
228 * the reserve counters are updated with the hugetlb_lock held. It is safe
229 * to reset the VMA at fork() time as it is not in use yet and there is no
230 * chance of the global counters getting corrupted as a result of the values.
232 * The private mapping reservation is represented in a subtly different
233 * manner to a shared mapping. A shared mapping has a region map associated
234 * with the underlying file, this region map represents the backing file
235 * pages which have ever had a reservation assigned which this persists even
236 * after the page is instantiated. A private mapping has a region map
237 * associated with the original mmap which is attached to all VMAs which
238 * reference it, this region map represents those offsets which have consumed
239 * reservation ie. where pages have been instantiated.
241 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
243 return (unsigned long)vma
->vm_private_data
;
246 static void set_vma_private_data(struct vm_area_struct
*vma
,
249 vma
->vm_private_data
= (void *)value
;
254 struct list_head regions
;
257 struct resv_map
*resv_map_alloc(void)
259 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
263 kref_init(&resv_map
->refs
);
264 INIT_LIST_HEAD(&resv_map
->regions
);
269 void resv_map_release(struct kref
*ref
)
271 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
273 /* Clear out any active regions before we release the map. */
274 region_truncate(&resv_map
->regions
, 0);
278 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
280 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
281 if (!(vma
->vm_flags
& VM_SHARED
))
282 return (struct resv_map
*)(get_vma_private_data(vma
) &
287 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
289 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
290 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
292 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
293 HPAGE_RESV_MASK
) | (unsigned long)map
);
296 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
298 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
299 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
301 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
304 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
306 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
308 return (get_vma_private_data(vma
) & flag
) != 0;
311 /* Decrement the reserved pages in the hugepage pool by one */
312 static void decrement_hugepage_resv_vma(struct vm_area_struct
*vma
)
314 if (vma
->vm_flags
& VM_NORESERVE
)
317 if (vma
->vm_flags
& VM_SHARED
) {
318 /* Shared mappings always use reserves */
320 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
322 * Only the process that called mmap() has reserves for
329 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
330 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
332 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
333 if (!(vma
->vm_flags
& VM_SHARED
))
334 vma
->vm_private_data
= (void *)0;
337 /* Returns true if the VMA has associated reserve pages */
338 static int vma_has_private_reserves(struct vm_area_struct
*vma
)
340 if (vma
->vm_flags
& VM_SHARED
)
342 if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
347 static void clear_huge_page(struct page
*page
, unsigned long addr
)
352 for (i
= 0; i
< (HPAGE_SIZE
/PAGE_SIZE
); i
++) {
354 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
358 static void copy_huge_page(struct page
*dst
, struct page
*src
,
359 unsigned long addr
, struct vm_area_struct
*vma
)
364 for (i
= 0; i
< HPAGE_SIZE
/PAGE_SIZE
; i
++) {
366 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
370 static void enqueue_huge_page(struct page
*page
)
372 int nid
= page_to_nid(page
);
373 list_add(&page
->lru
, &hugepage_freelists
[nid
]);
375 free_huge_pages_node
[nid
]++;
378 static struct page
*dequeue_huge_page(void)
381 struct page
*page
= NULL
;
383 for (nid
= 0; nid
< MAX_NUMNODES
; ++nid
) {
384 if (!list_empty(&hugepage_freelists
[nid
])) {
385 page
= list_entry(hugepage_freelists
[nid
].next
,
387 list_del(&page
->lru
);
389 free_huge_pages_node
[nid
]--;
396 static struct page
*dequeue_huge_page_vma(struct vm_area_struct
*vma
,
397 unsigned long address
, int avoid_reserve
)
400 struct page
*page
= NULL
;
401 struct mempolicy
*mpol
;
402 nodemask_t
*nodemask
;
403 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
404 htlb_alloc_mask
, &mpol
, &nodemask
);
409 * A child process with MAP_PRIVATE mappings created by their parent
410 * have no page reserves. This check ensures that reservations are
411 * not "stolen". The child may still get SIGKILLed
413 if (!vma_has_private_reserves(vma
) &&
414 free_huge_pages
- resv_huge_pages
== 0)
417 /* If reserves cannot be used, ensure enough pages are in the pool */
418 if (avoid_reserve
&& free_huge_pages
- resv_huge_pages
== 0)
421 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
422 MAX_NR_ZONES
- 1, nodemask
) {
423 nid
= zone_to_nid(zone
);
424 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
425 !list_empty(&hugepage_freelists
[nid
])) {
426 page
= list_entry(hugepage_freelists
[nid
].next
,
428 list_del(&page
->lru
);
430 free_huge_pages_node
[nid
]--;
433 decrement_hugepage_resv_vma(vma
);
442 static void update_and_free_page(struct page
*page
)
446 nr_huge_pages_node
[page_to_nid(page
)]--;
447 for (i
= 0; i
< (HPAGE_SIZE
/ PAGE_SIZE
); i
++) {
448 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
449 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
450 1 << PG_private
| 1<< PG_writeback
);
452 set_compound_page_dtor(page
, NULL
);
453 set_page_refcounted(page
);
454 arch_release_hugepage(page
);
455 __free_pages(page
, HUGETLB_PAGE_ORDER
);
458 static void free_huge_page(struct page
*page
)
460 int nid
= page_to_nid(page
);
461 struct address_space
*mapping
;
463 mapping
= (struct address_space
*) page_private(page
);
464 set_page_private(page
, 0);
465 BUG_ON(page_count(page
));
466 INIT_LIST_HEAD(&page
->lru
);
468 spin_lock(&hugetlb_lock
);
469 if (surplus_huge_pages_node
[nid
]) {
470 update_and_free_page(page
);
471 surplus_huge_pages
--;
472 surplus_huge_pages_node
[nid
]--;
474 enqueue_huge_page(page
);
476 spin_unlock(&hugetlb_lock
);
478 hugetlb_put_quota(mapping
, 1);
482 * Increment or decrement surplus_huge_pages. Keep node-specific counters
483 * balanced by operating on them in a round-robin fashion.
484 * Returns 1 if an adjustment was made.
486 static int adjust_pool_surplus(int delta
)
492 VM_BUG_ON(delta
!= -1 && delta
!= 1);
494 nid
= next_node(nid
, node_online_map
);
495 if (nid
== MAX_NUMNODES
)
496 nid
= first_node(node_online_map
);
498 /* To shrink on this node, there must be a surplus page */
499 if (delta
< 0 && !surplus_huge_pages_node
[nid
])
501 /* Surplus cannot exceed the total number of pages */
502 if (delta
> 0 && surplus_huge_pages_node
[nid
] >=
503 nr_huge_pages_node
[nid
])
506 surplus_huge_pages
+= delta
;
507 surplus_huge_pages_node
[nid
] += delta
;
510 } while (nid
!= prev_nid
);
516 static void prep_new_huge_page(struct page
*page
, int nid
)
518 set_compound_page_dtor(page
, free_huge_page
);
519 spin_lock(&hugetlb_lock
);
521 nr_huge_pages_node
[nid
]++;
522 spin_unlock(&hugetlb_lock
);
523 put_page(page
); /* free it into the hugepage allocator */
526 static struct page
*alloc_fresh_huge_page_node(int nid
)
530 page
= alloc_pages_node(nid
,
531 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
532 __GFP_REPEAT
|__GFP_NOWARN
,
535 if (arch_prepare_hugepage(page
)) {
536 __free_pages(page
, HUGETLB_PAGE_ORDER
);
539 prep_new_huge_page(page
, nid
);
545 static int alloc_fresh_huge_page(void)
552 start_nid
= hugetlb_next_nid
;
555 page
= alloc_fresh_huge_page_node(hugetlb_next_nid
);
559 * Use a helper variable to find the next node and then
560 * copy it back to hugetlb_next_nid afterwards:
561 * otherwise there's a window in which a racer might
562 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
563 * But we don't need to use a spin_lock here: it really
564 * doesn't matter if occasionally a racer chooses the
565 * same nid as we do. Move nid forward in the mask even
566 * if we just successfully allocated a hugepage so that
567 * the next caller gets hugepages on the next node.
569 next_nid
= next_node(hugetlb_next_nid
, node_online_map
);
570 if (next_nid
== MAX_NUMNODES
)
571 next_nid
= first_node(node_online_map
);
572 hugetlb_next_nid
= next_nid
;
573 } while (!page
&& hugetlb_next_nid
!= start_nid
);
576 count_vm_event(HTLB_BUDDY_PGALLOC
);
578 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
583 static struct page
*alloc_buddy_huge_page(struct vm_area_struct
*vma
,
584 unsigned long address
)
590 * Assume we will successfully allocate the surplus page to
591 * prevent racing processes from causing the surplus to exceed
594 * This however introduces a different race, where a process B
595 * tries to grow the static hugepage pool while alloc_pages() is
596 * called by process A. B will only examine the per-node
597 * counters in determining if surplus huge pages can be
598 * converted to normal huge pages in adjust_pool_surplus(). A
599 * won't be able to increment the per-node counter, until the
600 * lock is dropped by B, but B doesn't drop hugetlb_lock until
601 * no more huge pages can be converted from surplus to normal
602 * state (and doesn't try to convert again). Thus, we have a
603 * case where a surplus huge page exists, the pool is grown, and
604 * the surplus huge page still exists after, even though it
605 * should just have been converted to a normal huge page. This
606 * does not leak memory, though, as the hugepage will be freed
607 * once it is out of use. It also does not allow the counters to
608 * go out of whack in adjust_pool_surplus() as we don't modify
609 * the node values until we've gotten the hugepage and only the
610 * per-node value is checked there.
612 spin_lock(&hugetlb_lock
);
613 if (surplus_huge_pages
>= nr_overcommit_huge_pages
) {
614 spin_unlock(&hugetlb_lock
);
618 surplus_huge_pages
++;
620 spin_unlock(&hugetlb_lock
);
622 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
623 __GFP_REPEAT
|__GFP_NOWARN
,
626 spin_lock(&hugetlb_lock
);
629 * This page is now managed by the hugetlb allocator and has
630 * no users -- drop the buddy allocator's reference.
632 put_page_testzero(page
);
633 VM_BUG_ON(page_count(page
));
634 nid
= page_to_nid(page
);
635 set_compound_page_dtor(page
, free_huge_page
);
637 * We incremented the global counters already
639 nr_huge_pages_node
[nid
]++;
640 surplus_huge_pages_node
[nid
]++;
641 __count_vm_event(HTLB_BUDDY_PGALLOC
);
644 surplus_huge_pages
--;
645 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
647 spin_unlock(&hugetlb_lock
);
653 * Increase the hugetlb pool such that it can accomodate a reservation
656 static int gather_surplus_pages(int delta
)
658 struct list_head surplus_list
;
659 struct page
*page
, *tmp
;
661 int needed
, allocated
;
663 needed
= (resv_huge_pages
+ delta
) - free_huge_pages
;
665 resv_huge_pages
+= delta
;
670 INIT_LIST_HEAD(&surplus_list
);
674 spin_unlock(&hugetlb_lock
);
675 for (i
= 0; i
< needed
; i
++) {
676 page
= alloc_buddy_huge_page(NULL
, 0);
679 * We were not able to allocate enough pages to
680 * satisfy the entire reservation so we free what
681 * we've allocated so far.
683 spin_lock(&hugetlb_lock
);
688 list_add(&page
->lru
, &surplus_list
);
693 * After retaking hugetlb_lock, we need to recalculate 'needed'
694 * because either resv_huge_pages or free_huge_pages may have changed.
696 spin_lock(&hugetlb_lock
);
697 needed
= (resv_huge_pages
+ delta
) - (free_huge_pages
+ allocated
);
702 * The surplus_list now contains _at_least_ the number of extra pages
703 * needed to accomodate the reservation. Add the appropriate number
704 * of pages to the hugetlb pool and free the extras back to the buddy
705 * allocator. Commit the entire reservation here to prevent another
706 * process from stealing the pages as they are added to the pool but
707 * before they are reserved.
710 resv_huge_pages
+= delta
;
713 /* Free the needed pages to the hugetlb pool */
714 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
717 list_del(&page
->lru
);
718 enqueue_huge_page(page
);
721 /* Free unnecessary surplus pages to the buddy allocator */
722 if (!list_empty(&surplus_list
)) {
723 spin_unlock(&hugetlb_lock
);
724 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
725 list_del(&page
->lru
);
727 * The page has a reference count of zero already, so
728 * call free_huge_page directly instead of using
729 * put_page. This must be done with hugetlb_lock
730 * unlocked which is safe because free_huge_page takes
731 * hugetlb_lock before deciding how to free the page.
733 free_huge_page(page
);
735 spin_lock(&hugetlb_lock
);
742 * When releasing a hugetlb pool reservation, any surplus pages that were
743 * allocated to satisfy the reservation must be explicitly freed if they were
746 static void return_unused_surplus_pages(unsigned long unused_resv_pages
)
750 unsigned long nr_pages
;
753 * We want to release as many surplus pages as possible, spread
754 * evenly across all nodes. Iterate across all nodes until we
755 * can no longer free unreserved surplus pages. This occurs when
756 * the nodes with surplus pages have no free pages.
758 unsigned long remaining_iterations
= num_online_nodes();
760 /* Uncommit the reservation */
761 resv_huge_pages
-= unused_resv_pages
;
763 nr_pages
= min(unused_resv_pages
, surplus_huge_pages
);
765 while (remaining_iterations
-- && nr_pages
) {
766 nid
= next_node(nid
, node_online_map
);
767 if (nid
== MAX_NUMNODES
)
768 nid
= first_node(node_online_map
);
770 if (!surplus_huge_pages_node
[nid
])
773 if (!list_empty(&hugepage_freelists
[nid
])) {
774 page
= list_entry(hugepage_freelists
[nid
].next
,
776 list_del(&page
->lru
);
777 update_and_free_page(page
);
779 free_huge_pages_node
[nid
]--;
780 surplus_huge_pages
--;
781 surplus_huge_pages_node
[nid
]--;
783 remaining_iterations
= num_online_nodes();
789 * Determine if the huge page at addr within the vma has an associated
790 * reservation. Where it does not we will need to logically increase
791 * reservation and actually increase quota before an allocation can occur.
792 * Where any new reservation would be required the reservation change is
793 * prepared, but not committed. Once the page has been quota'd allocated
794 * an instantiated the change should be committed via vma_commit_reservation.
795 * No action is required on failure.
797 static int vma_needs_reservation(struct vm_area_struct
*vma
, unsigned long addr
)
799 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
800 struct inode
*inode
= mapping
->host
;
802 if (vma
->vm_flags
& VM_SHARED
) {
803 pgoff_t idx
= vma_hugecache_offset(vma
, addr
);
804 return region_chg(&inode
->i_mapping
->private_list
,
807 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
812 pgoff_t idx
= vma_hugecache_offset(vma
, addr
);
813 struct resv_map
*reservations
= vma_resv_map(vma
);
815 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
821 static void vma_commit_reservation(struct vm_area_struct
*vma
,
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(vma
, addr
);
829 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
831 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
832 pgoff_t idx
= vma_hugecache_offset(vma
, addr
);
833 struct resv_map
*reservations
= vma_resv_map(vma
);
835 /* Mark this page used in the map. */
836 region_add(&reservations
->regions
, idx
, idx
+ 1);
840 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
841 unsigned long addr
, int avoid_reserve
)
844 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
845 struct inode
*inode
= mapping
->host
;
849 * Processes that did not create the mapping will have no reserves and
850 * will not have accounted against quota. Check that the quota can be
851 * made before satisfying the allocation
852 * MAP_NORESERVE mappings may also need pages and quota allocated
853 * if no reserve mapping overlaps.
855 chg
= vma_needs_reservation(vma
, addr
);
859 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
860 return ERR_PTR(-ENOSPC
);
862 spin_lock(&hugetlb_lock
);
863 page
= dequeue_huge_page_vma(vma
, addr
, avoid_reserve
);
864 spin_unlock(&hugetlb_lock
);
867 page
= alloc_buddy_huge_page(vma
, addr
);
869 hugetlb_put_quota(inode
->i_mapping
, chg
);
870 return ERR_PTR(-VM_FAULT_OOM
);
874 set_page_refcounted(page
);
875 set_page_private(page
, (unsigned long) mapping
);
877 vma_commit_reservation(vma
, addr
);
882 static int __init
hugetlb_init(void)
886 if (HPAGE_SHIFT
== 0)
889 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
890 INIT_LIST_HEAD(&hugepage_freelists
[i
]);
892 hugetlb_next_nid
= first_node(node_online_map
);
894 for (i
= 0; i
< max_huge_pages
; ++i
) {
895 if (!alloc_fresh_huge_page())
898 max_huge_pages
= free_huge_pages
= nr_huge_pages
= i
;
899 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages
);
902 module_init(hugetlb_init
);
904 static int __init
hugetlb_setup(char *s
)
906 if (sscanf(s
, "%lu", &max_huge_pages
) <= 0)
910 __setup("hugepages=", hugetlb_setup
);
912 static unsigned int cpuset_mems_nr(unsigned int *array
)
917 for_each_node_mask(node
, cpuset_current_mems_allowed
)
924 #ifdef CONFIG_HIGHMEM
925 static void try_to_free_low(unsigned long count
)
929 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
930 struct page
*page
, *next
;
931 list_for_each_entry_safe(page
, next
, &hugepage_freelists
[i
], lru
) {
932 if (count
>= nr_huge_pages
)
934 if (PageHighMem(page
))
936 list_del(&page
->lru
);
937 update_and_free_page(page
);
939 free_huge_pages_node
[page_to_nid(page
)]--;
944 static inline void try_to_free_low(unsigned long count
)
949 #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
950 static unsigned long set_max_huge_pages(unsigned long count
)
952 unsigned long min_count
, ret
;
955 * Increase the pool size
956 * First take pages out of surplus state. Then make up the
957 * remaining difference by allocating fresh huge pages.
959 * We might race with alloc_buddy_huge_page() here and be unable
960 * to convert a surplus huge page to a normal huge page. That is
961 * not critical, though, it just means the overall size of the
962 * pool might be one hugepage larger than it needs to be, but
963 * within all the constraints specified by the sysctls.
965 spin_lock(&hugetlb_lock
);
966 while (surplus_huge_pages
&& count
> persistent_huge_pages
) {
967 if (!adjust_pool_surplus(-1))
971 while (count
> persistent_huge_pages
) {
973 * If this allocation races such that we no longer need the
974 * page, free_huge_page will handle it by freeing the page
975 * and reducing the surplus.
977 spin_unlock(&hugetlb_lock
);
978 ret
= alloc_fresh_huge_page();
979 spin_lock(&hugetlb_lock
);
986 * Decrease the pool size
987 * First return free pages to the buddy allocator (being careful
988 * to keep enough around to satisfy reservations). Then place
989 * pages into surplus state as needed so the pool will shrink
990 * to the desired size as pages become free.
992 * By placing pages into the surplus state independent of the
993 * overcommit value, we are allowing the surplus pool size to
994 * exceed overcommit. There are few sane options here. Since
995 * alloc_buddy_huge_page() is checking the global counter,
996 * though, we'll note that we're not allowed to exceed surplus
997 * and won't grow the pool anywhere else. Not until one of the
998 * sysctls are changed, or the surplus pages go out of use.
1000 min_count
= resv_huge_pages
+ nr_huge_pages
- free_huge_pages
;
1001 min_count
= max(count
, min_count
);
1002 try_to_free_low(min_count
);
1003 while (min_count
< persistent_huge_pages
) {
1004 struct page
*page
= dequeue_huge_page();
1007 update_and_free_page(page
);
1009 while (count
< persistent_huge_pages
) {
1010 if (!adjust_pool_surplus(1))
1014 ret
= persistent_huge_pages
;
1015 spin_unlock(&hugetlb_lock
);
1019 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1020 struct file
*file
, void __user
*buffer
,
1021 size_t *length
, loff_t
*ppos
)
1023 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1024 max_huge_pages
= set_max_huge_pages(max_huge_pages
);
1028 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1029 struct file
*file
, void __user
*buffer
,
1030 size_t *length
, loff_t
*ppos
)
1032 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
1033 if (hugepages_treat_as_movable
)
1034 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1036 htlb_alloc_mask
= GFP_HIGHUSER
;
1040 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1041 struct file
*file
, void __user
*buffer
,
1042 size_t *length
, loff_t
*ppos
)
1044 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1045 spin_lock(&hugetlb_lock
);
1046 nr_overcommit_huge_pages
= sysctl_overcommit_huge_pages
;
1047 spin_unlock(&hugetlb_lock
);
1051 #endif /* CONFIG_SYSCTL */
1053 int hugetlb_report_meminfo(char *buf
)
1056 "HugePages_Total: %5lu\n"
1057 "HugePages_Free: %5lu\n"
1058 "HugePages_Rsvd: %5lu\n"
1059 "HugePages_Surp: %5lu\n"
1060 "Hugepagesize: %5lu kB\n",
1068 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1071 "Node %d HugePages_Total: %5u\n"
1072 "Node %d HugePages_Free: %5u\n"
1073 "Node %d HugePages_Surp: %5u\n",
1074 nid
, nr_huge_pages_node
[nid
],
1075 nid
, free_huge_pages_node
[nid
],
1076 nid
, surplus_huge_pages_node
[nid
]);
1079 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1080 unsigned long hugetlb_total_pages(void)
1082 return nr_huge_pages
* (HPAGE_SIZE
/ PAGE_SIZE
);
1085 static int hugetlb_acct_memory(long delta
)
1089 spin_lock(&hugetlb_lock
);
1091 * When cpuset is configured, it breaks the strict hugetlb page
1092 * reservation as the accounting is done on a global variable. Such
1093 * reservation is completely rubbish in the presence of cpuset because
1094 * the reservation is not checked against page availability for the
1095 * current cpuset. Application can still potentially OOM'ed by kernel
1096 * with lack of free htlb page in cpuset that the task is in.
1097 * Attempt to enforce strict accounting with cpuset is almost
1098 * impossible (or too ugly) because cpuset is too fluid that
1099 * task or memory node can be dynamically moved between cpusets.
1101 * The change of semantics for shared hugetlb mapping with cpuset is
1102 * undesirable. However, in order to preserve some of the semantics,
1103 * we fall back to check against current free page availability as
1104 * a best attempt and hopefully to minimize the impact of changing
1105 * semantics that cpuset has.
1108 if (gather_surplus_pages(delta
) < 0)
1111 if (delta
> cpuset_mems_nr(free_huge_pages_node
)) {
1112 return_unused_surplus_pages(delta
);
1119 return_unused_surplus_pages((unsigned long) -delta
);
1122 spin_unlock(&hugetlb_lock
);
1126 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
1128 struct resv_map
*reservations
= vma_resv_map(vma
);
1131 * This new VMA should share its siblings reservation map if present.
1132 * The VMA will only ever have a valid reservation map pointer where
1133 * it is being copied for another still existing VMA. As that VMA
1134 * has a reference to the reservation map it cannot dissappear until
1135 * after this open call completes. It is therefore safe to take a
1136 * new reference here without additional locking.
1139 kref_get(&reservations
->refs
);
1142 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
1144 struct resv_map
*reservations
= vma_resv_map(vma
);
1145 unsigned long reserve
;
1146 unsigned long start
;
1150 start
= vma_hugecache_offset(vma
, vma
->vm_start
);
1151 end
= vma_hugecache_offset(vma
, vma
->vm_end
);
1153 reserve
= (end
- start
) -
1154 region_count(&reservations
->regions
, start
, end
);
1156 kref_put(&reservations
->refs
, resv_map_release
);
1159 hugetlb_acct_memory(-reserve
);
1164 * We cannot handle pagefaults against hugetlb pages at all. They cause
1165 * handle_mm_fault() to try to instantiate regular-sized pages in the
1166 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1169 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1175 struct vm_operations_struct hugetlb_vm_ops
= {
1176 .fault
= hugetlb_vm_op_fault
,
1177 .open
= hugetlb_vm_op_open
,
1178 .close
= hugetlb_vm_op_close
,
1181 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
1188 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
1190 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
1192 entry
= pte_mkyoung(entry
);
1193 entry
= pte_mkhuge(entry
);
1198 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
1199 unsigned long address
, pte_t
*ptep
)
1203 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
1204 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
1205 update_mmu_cache(vma
, address
, entry
);
1210 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
1211 struct vm_area_struct
*vma
)
1213 pte_t
*src_pte
, *dst_pte
, entry
;
1214 struct page
*ptepage
;
1218 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
1220 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= HPAGE_SIZE
) {
1221 src_pte
= huge_pte_offset(src
, addr
);
1224 dst_pte
= huge_pte_alloc(dst
, addr
);
1228 /* If the pagetables are shared don't copy or take references */
1229 if (dst_pte
== src_pte
)
1232 spin_lock(&dst
->page_table_lock
);
1233 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
1234 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
1236 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
1237 entry
= huge_ptep_get(src_pte
);
1238 ptepage
= pte_page(entry
);
1240 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
1242 spin_unlock(&src
->page_table_lock
);
1243 spin_unlock(&dst
->page_table_lock
);
1251 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1252 unsigned long end
, struct page
*ref_page
)
1254 struct mm_struct
*mm
= vma
->vm_mm
;
1255 unsigned long address
;
1261 * A page gathering list, protected by per file i_mmap_lock. The
1262 * lock is used to avoid list corruption from multiple unmapping
1263 * of the same page since we are using page->lru.
1265 LIST_HEAD(page_list
);
1267 WARN_ON(!is_vm_hugetlb_page(vma
));
1268 BUG_ON(start
& ~HPAGE_MASK
);
1269 BUG_ON(end
& ~HPAGE_MASK
);
1271 spin_lock(&mm
->page_table_lock
);
1272 for (address
= start
; address
< end
; address
+= HPAGE_SIZE
) {
1273 ptep
= huge_pte_offset(mm
, address
);
1277 if (huge_pmd_unshare(mm
, &address
, ptep
))
1281 * If a reference page is supplied, it is because a specific
1282 * page is being unmapped, not a range. Ensure the page we
1283 * are about to unmap is the actual page of interest.
1286 pte
= huge_ptep_get(ptep
);
1287 if (huge_pte_none(pte
))
1289 page
= pte_page(pte
);
1290 if (page
!= ref_page
)
1294 * Mark the VMA as having unmapped its page so that
1295 * future faults in this VMA will fail rather than
1296 * looking like data was lost
1298 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
1301 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1302 if (huge_pte_none(pte
))
1305 page
= pte_page(pte
);
1307 set_page_dirty(page
);
1308 list_add(&page
->lru
, &page_list
);
1310 spin_unlock(&mm
->page_table_lock
);
1311 flush_tlb_range(vma
, start
, end
);
1312 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
1313 list_del(&page
->lru
);
1318 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1319 unsigned long end
, struct page
*ref_page
)
1322 * It is undesirable to test vma->vm_file as it should be non-null
1323 * for valid hugetlb area. However, vm_file will be NULL in the error
1324 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
1325 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
1326 * to clean up. Since no pte has actually been setup, it is safe to
1327 * do nothing in this case.
1330 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1331 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
1332 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1337 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1338 * mappping it owns the reserve page for. The intention is to unmap the page
1339 * from other VMAs and let the children be SIGKILLed if they are faulting the
1342 int unmap_ref_private(struct mm_struct
*mm
,
1343 struct vm_area_struct
*vma
,
1345 unsigned long address
)
1347 struct vm_area_struct
*iter_vma
;
1348 struct address_space
*mapping
;
1349 struct prio_tree_iter iter
;
1353 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1354 * from page cache lookup which is in HPAGE_SIZE units.
1356 address
= address
& huge_page_mask(hstate_vma(vma
));
1357 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
1358 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
1359 mapping
= (struct address_space
*)page_private(page
);
1361 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1362 /* Do not unmap the current VMA */
1363 if (iter_vma
== vma
)
1367 * Unmap the page from other VMAs without their own reserves.
1368 * They get marked to be SIGKILLed if they fault in these
1369 * areas. This is because a future no-page fault on this VMA
1370 * could insert a zeroed page instead of the data existing
1371 * from the time of fork. This would look like data corruption
1373 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
1374 unmap_hugepage_range(iter_vma
,
1375 address
, address
+ HPAGE_SIZE
,
1382 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1383 unsigned long address
, pte_t
*ptep
, pte_t pte
,
1384 struct page
*pagecache_page
)
1386 struct page
*old_page
, *new_page
;
1388 int outside_reserve
= 0;
1390 old_page
= pte_page(pte
);
1393 /* If no-one else is actually using this page, avoid the copy
1394 * and just make the page writable */
1395 avoidcopy
= (page_count(old_page
) == 1);
1397 set_huge_ptep_writable(vma
, address
, ptep
);
1402 * If the process that created a MAP_PRIVATE mapping is about to
1403 * perform a COW due to a shared page count, attempt to satisfy
1404 * the allocation without using the existing reserves. The pagecache
1405 * page is used to determine if the reserve at this address was
1406 * consumed or not. If reserves were used, a partial faulted mapping
1407 * at the time of fork() could consume its reserves on COW instead
1408 * of the full address range.
1410 if (!(vma
->vm_flags
& VM_SHARED
) &&
1411 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
1412 old_page
!= pagecache_page
)
1413 outside_reserve
= 1;
1415 page_cache_get(old_page
);
1416 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
1418 if (IS_ERR(new_page
)) {
1419 page_cache_release(old_page
);
1422 * If a process owning a MAP_PRIVATE mapping fails to COW,
1423 * it is due to references held by a child and an insufficient
1424 * huge page pool. To guarantee the original mappers
1425 * reliability, unmap the page from child processes. The child
1426 * may get SIGKILLed if it later faults.
1428 if (outside_reserve
) {
1429 BUG_ON(huge_pte_none(pte
));
1430 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
1431 BUG_ON(page_count(old_page
) != 1);
1432 BUG_ON(huge_pte_none(pte
));
1433 goto retry_avoidcopy
;
1438 return -PTR_ERR(new_page
);
1441 spin_unlock(&mm
->page_table_lock
);
1442 copy_huge_page(new_page
, old_page
, address
, vma
);
1443 __SetPageUptodate(new_page
);
1444 spin_lock(&mm
->page_table_lock
);
1446 ptep
= huge_pte_offset(mm
, address
& HPAGE_MASK
);
1447 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
1449 huge_ptep_clear_flush(vma
, address
, ptep
);
1450 set_huge_pte_at(mm
, address
, ptep
,
1451 make_huge_pte(vma
, new_page
, 1));
1452 /* Make the old page be freed below */
1453 new_page
= old_page
;
1455 page_cache_release(new_page
);
1456 page_cache_release(old_page
);
1460 /* Return the pagecache page at a given address within a VMA */
1461 static struct page
*hugetlbfs_pagecache_page(struct vm_area_struct
*vma
,
1462 unsigned long address
)
1464 struct address_space
*mapping
;
1467 mapping
= vma
->vm_file
->f_mapping
;
1468 idx
= vma_hugecache_offset(vma
, address
);
1470 return find_lock_page(mapping
, idx
);
1473 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1474 unsigned long address
, pte_t
*ptep
, int write_access
)
1476 int ret
= VM_FAULT_SIGBUS
;
1480 struct address_space
*mapping
;
1484 * Currently, we are forced to kill the process in the event the
1485 * original mapper has unmapped pages from the child due to a failed
1486 * COW. Warn that such a situation has occured as it may not be obvious
1488 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
1490 "PID %d killed due to inadequate hugepage pool\n",
1495 mapping
= vma
->vm_file
->f_mapping
;
1496 idx
= vma_hugecache_offset(vma
, address
);
1499 * Use page lock to guard against racing truncation
1500 * before we get page_table_lock.
1503 page
= find_lock_page(mapping
, idx
);
1505 size
= i_size_read(mapping
->host
) >> HPAGE_SHIFT
;
1508 page
= alloc_huge_page(vma
, address
, 0);
1510 ret
= -PTR_ERR(page
);
1513 clear_huge_page(page
, address
);
1514 __SetPageUptodate(page
);
1516 if (vma
->vm_flags
& VM_SHARED
) {
1518 struct inode
*inode
= mapping
->host
;
1520 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
1528 spin_lock(&inode
->i_lock
);
1529 inode
->i_blocks
+= BLOCKS_PER_HUGEPAGE
;
1530 spin_unlock(&inode
->i_lock
);
1535 spin_lock(&mm
->page_table_lock
);
1536 size
= i_size_read(mapping
->host
) >> HPAGE_SHIFT
;
1541 if (!huge_pte_none(huge_ptep_get(ptep
)))
1544 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
1545 && (vma
->vm_flags
& VM_SHARED
)));
1546 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
1548 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1549 /* Optimization, do the COW without a second fault */
1550 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
1553 spin_unlock(&mm
->page_table_lock
);
1559 spin_unlock(&mm
->page_table_lock
);
1565 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1566 unsigned long address
, int write_access
)
1571 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
1573 ptep
= huge_pte_alloc(mm
, address
);
1575 return VM_FAULT_OOM
;
1578 * Serialize hugepage allocation and instantiation, so that we don't
1579 * get spurious allocation failures if two CPUs race to instantiate
1580 * the same page in the page cache.
1582 mutex_lock(&hugetlb_instantiation_mutex
);
1583 entry
= huge_ptep_get(ptep
);
1584 if (huge_pte_none(entry
)) {
1585 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
1586 mutex_unlock(&hugetlb_instantiation_mutex
);
1592 spin_lock(&mm
->page_table_lock
);
1593 /* Check for a racing update before calling hugetlb_cow */
1594 if (likely(pte_same(entry
, huge_ptep_get(ptep
))))
1595 if (write_access
&& !pte_write(entry
)) {
1597 page
= hugetlbfs_pagecache_page(vma
, address
);
1598 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
, page
);
1604 spin_unlock(&mm
->page_table_lock
);
1605 mutex_unlock(&hugetlb_instantiation_mutex
);
1610 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1611 struct page
**pages
, struct vm_area_struct
**vmas
,
1612 unsigned long *position
, int *length
, int i
,
1615 unsigned long pfn_offset
;
1616 unsigned long vaddr
= *position
;
1617 int remainder
= *length
;
1619 spin_lock(&mm
->page_table_lock
);
1620 while (vaddr
< vma
->vm_end
&& remainder
) {
1625 * Some archs (sparc64, sh*) have multiple pte_ts to
1626 * each hugepage. We have to make * sure we get the
1627 * first, for the page indexing below to work.
1629 pte
= huge_pte_offset(mm
, vaddr
& HPAGE_MASK
);
1631 if (!pte
|| huge_pte_none(huge_ptep_get(pte
)) ||
1632 (write
&& !pte_write(huge_ptep_get(pte
)))) {
1635 spin_unlock(&mm
->page_table_lock
);
1636 ret
= hugetlb_fault(mm
, vma
, vaddr
, write
);
1637 spin_lock(&mm
->page_table_lock
);
1638 if (!(ret
& VM_FAULT_ERROR
))
1647 pfn_offset
= (vaddr
& ~HPAGE_MASK
) >> PAGE_SHIFT
;
1648 page
= pte_page(huge_ptep_get(pte
));
1652 pages
[i
] = page
+ pfn_offset
;
1662 if (vaddr
< vma
->vm_end
&& remainder
&&
1663 pfn_offset
< HPAGE_SIZE
/PAGE_SIZE
) {
1665 * We use pfn_offset to avoid touching the pageframes
1666 * of this compound page.
1671 spin_unlock(&mm
->page_table_lock
);
1672 *length
= remainder
;
1678 void hugetlb_change_protection(struct vm_area_struct
*vma
,
1679 unsigned long address
, unsigned long end
, pgprot_t newprot
)
1681 struct mm_struct
*mm
= vma
->vm_mm
;
1682 unsigned long start
= address
;
1686 BUG_ON(address
>= end
);
1687 flush_cache_range(vma
, address
, end
);
1689 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1690 spin_lock(&mm
->page_table_lock
);
1691 for (; address
< end
; address
+= HPAGE_SIZE
) {
1692 ptep
= huge_pte_offset(mm
, address
);
1695 if (huge_pmd_unshare(mm
, &address
, ptep
))
1697 if (!huge_pte_none(huge_ptep_get(ptep
))) {
1698 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1699 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
1700 set_huge_pte_at(mm
, address
, ptep
, pte
);
1703 spin_unlock(&mm
->page_table_lock
);
1704 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1706 flush_tlb_range(vma
, start
, end
);
1709 int hugetlb_reserve_pages(struct inode
*inode
,
1711 struct vm_area_struct
*vma
)
1715 if (vma
&& vma
->vm_flags
& VM_NORESERVE
)
1719 * Shared mappings base their reservation on the number of pages that
1720 * are already allocated on behalf of the file. Private mappings need
1721 * to reserve the full area even if read-only as mprotect() may be
1722 * called to make the mapping read-write. Assume !vma is a shm mapping
1724 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
1725 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
1727 struct resv_map
*resv_map
= resv_map_alloc();
1733 set_vma_resv_map(vma
, resv_map
);
1734 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
1740 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1742 ret
= hugetlb_acct_memory(chg
);
1744 hugetlb_put_quota(inode
->i_mapping
, chg
);
1747 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
1748 region_add(&inode
->i_mapping
->private_list
, from
, to
);
1752 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
1754 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
1756 spin_lock(&inode
->i_lock
);
1757 inode
->i_blocks
-= BLOCKS_PER_HUGEPAGE
* freed
;
1758 spin_unlock(&inode
->i_lock
);
1760 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
1761 hugetlb_acct_memory(-(chg
- freed
));