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/seq_file.h>
11 #include <linux/sysctl.h>
12 #include <linux/highmem.h>
13 #include <linux/mmu_notifier.h>
14 #include <linux/nodemask.h>
15 #include <linux/pagemap.h>
16 #include <linux/mempolicy.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
23 #include <asm/pgtable.h>
26 #include <linux/hugetlb.h>
29 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
30 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
31 unsigned long hugepages_treat_as_movable
;
33 static int max_hstate
;
34 unsigned int default_hstate_idx
;
35 struct hstate hstates
[HUGE_MAX_HSTATE
];
37 __initdata
LIST_HEAD(huge_boot_pages
);
39 /* for command line parsing */
40 static struct hstate
* __initdata parsed_hstate
;
41 static unsigned long __initdata default_hstate_max_huge_pages
;
42 static unsigned long __initdata default_hstate_size
;
44 #define for_each_hstate(h) \
45 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
48 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
50 static DEFINE_SPINLOCK(hugetlb_lock
);
53 * Region tracking -- allows tracking of reservations and instantiated pages
54 * across the pages in a mapping.
56 * The region data structures are protected by a combination of the mmap_sem
57 * and the hugetlb_instantion_mutex. To access or modify a region the caller
58 * must either hold the mmap_sem for write, or the mmap_sem for read and
59 * the hugetlb_instantiation mutex:
61 * down_write(&mm->mmap_sem);
63 * down_read(&mm->mmap_sem);
64 * mutex_lock(&hugetlb_instantiation_mutex);
67 struct list_head link
;
72 static long region_add(struct list_head
*head
, long f
, long t
)
74 struct file_region
*rg
, *nrg
, *trg
;
76 /* Locate the region we are either in or before. */
77 list_for_each_entry(rg
, head
, link
)
81 /* Round our left edge to the current segment if it encloses us. */
85 /* Check for and consume any regions we now overlap with. */
87 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
88 if (&rg
->link
== head
)
93 /* If this area reaches higher then extend our area to
94 * include it completely. If this is not the first area
95 * which we intend to reuse, free it. */
108 static long region_chg(struct list_head
*head
, long f
, long t
)
110 struct file_region
*rg
, *nrg
;
113 /* Locate the region we are before or in. */
114 list_for_each_entry(rg
, head
, link
)
118 /* If we are below the current region then a new region is required.
119 * Subtle, allocate a new region at the position but make it zero
120 * size such that we can guarantee to record the reservation. */
121 if (&rg
->link
== head
|| t
< rg
->from
) {
122 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
127 INIT_LIST_HEAD(&nrg
->link
);
128 list_add(&nrg
->link
, rg
->link
.prev
);
133 /* Round our left edge to the current segment if it encloses us. */
138 /* Check for and consume any regions we now overlap with. */
139 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
140 if (&rg
->link
== head
)
145 /* We overlap with this area, if it extends futher than
146 * us then we must extend ourselves. Account for its
147 * existing reservation. */
152 chg
-= rg
->to
- rg
->from
;
157 static long region_truncate(struct list_head
*head
, long end
)
159 struct file_region
*rg
, *trg
;
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg
, head
, link
)
166 if (&rg
->link
== head
)
169 /* If we are in the middle of a region then adjust it. */
170 if (end
> rg
->from
) {
173 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
176 /* Drop any remaining regions. */
177 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
178 if (&rg
->link
== head
)
180 chg
+= rg
->to
- rg
->from
;
187 static long region_count(struct list_head
*head
, long f
, long t
)
189 struct file_region
*rg
;
192 /* Locate each segment we overlap with, and count that overlap. */
193 list_for_each_entry(rg
, head
, link
) {
202 seg_from
= max(rg
->from
, f
);
203 seg_to
= min(rg
->to
, t
);
205 chg
+= seg_to
- seg_from
;
212 * Convert the address within this vma to the page offset within
213 * the mapping, in pagecache page units; huge pages here.
215 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
216 struct vm_area_struct
*vma
, unsigned long address
)
218 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
219 (vma
->vm_pgoff
>> huge_page_order(h
));
223 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
224 * bits of the reservation map pointer, which are always clear due to
227 #define HPAGE_RESV_OWNER (1UL << 0)
228 #define HPAGE_RESV_UNMAPPED (1UL << 1)
229 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
232 * These helpers are used to track how many pages are reserved for
233 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
234 * is guaranteed to have their future faults succeed.
236 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
237 * the reserve counters are updated with the hugetlb_lock held. It is safe
238 * to reset the VMA at fork() time as it is not in use yet and there is no
239 * chance of the global counters getting corrupted as a result of the values.
241 * The private mapping reservation is represented in a subtly different
242 * manner to a shared mapping. A shared mapping has a region map associated
243 * with the underlying file, this region map represents the backing file
244 * pages which have ever had a reservation assigned which this persists even
245 * after the page is instantiated. A private mapping has a region map
246 * associated with the original mmap which is attached to all VMAs which
247 * reference it, this region map represents those offsets which have consumed
248 * reservation ie. where pages have been instantiated.
250 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
252 return (unsigned long)vma
->vm_private_data
;
255 static void set_vma_private_data(struct vm_area_struct
*vma
,
258 vma
->vm_private_data
= (void *)value
;
263 struct list_head regions
;
266 static struct resv_map
*resv_map_alloc(void)
268 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
272 kref_init(&resv_map
->refs
);
273 INIT_LIST_HEAD(&resv_map
->regions
);
278 static void resv_map_release(struct kref
*ref
)
280 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
282 /* Clear out any active regions before we release the map. */
283 region_truncate(&resv_map
->regions
, 0);
287 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
289 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
290 if (!(vma
->vm_flags
& VM_SHARED
))
291 return (struct resv_map
*)(get_vma_private_data(vma
) &
296 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
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
) &
302 HPAGE_RESV_MASK
) | (unsigned long)map
);
305 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
307 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
308 VM_BUG_ON(vma
->vm_flags
& VM_SHARED
);
310 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
313 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
315 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
317 return (get_vma_private_data(vma
) & flag
) != 0;
320 /* Decrement the reserved pages in the hugepage pool by one */
321 static void decrement_hugepage_resv_vma(struct hstate
*h
,
322 struct vm_area_struct
*vma
)
324 if (vma
->vm_flags
& VM_NORESERVE
)
327 if (vma
->vm_flags
& VM_SHARED
) {
328 /* Shared mappings always use reserves */
329 h
->resv_huge_pages
--;
330 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
332 * Only the process that called mmap() has reserves for
335 h
->resv_huge_pages
--;
339 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
340 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
342 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
343 if (!(vma
->vm_flags
& VM_SHARED
))
344 vma
->vm_private_data
= (void *)0;
347 /* Returns true if the VMA has associated reserve pages */
348 static int vma_has_reserves(struct vm_area_struct
*vma
)
350 if (vma
->vm_flags
& VM_SHARED
)
352 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
357 static void clear_gigantic_page(struct page
*page
,
358 unsigned long addr
, unsigned long sz
)
361 struct page
*p
= page
;
364 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++, p
= mem_map_next(p
, page
, i
)) {
366 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
369 static void clear_huge_page(struct page
*page
,
370 unsigned long addr
, unsigned long sz
)
374 if (unlikely(sz
> MAX_ORDER_NR_PAGES
))
375 return clear_gigantic_page(page
, addr
, sz
);
378 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
380 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
384 static void copy_gigantic_page(struct page
*dst
, struct page
*src
,
385 unsigned long addr
, struct vm_area_struct
*vma
)
388 struct hstate
*h
= hstate_vma(vma
);
389 struct page
*dst_base
= dst
;
390 struct page
*src_base
= src
;
392 for (i
= 0; i
< pages_per_huge_page(h
); ) {
394 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
397 dst
= mem_map_next(dst
, dst_base
, i
);
398 src
= mem_map_next(src
, src_base
, i
);
401 static void copy_huge_page(struct page
*dst
, struct page
*src
,
402 unsigned long addr
, struct vm_area_struct
*vma
)
405 struct hstate
*h
= hstate_vma(vma
);
407 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
))
408 return copy_gigantic_page(dst
, src
, addr
, vma
);
411 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
413 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
417 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
419 int nid
= page_to_nid(page
);
420 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
421 h
->free_huge_pages
++;
422 h
->free_huge_pages_node
[nid
]++;
425 static struct page
*dequeue_huge_page(struct hstate
*h
)
428 struct page
*page
= NULL
;
430 for (nid
= 0; nid
< MAX_NUMNODES
; ++nid
) {
431 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
432 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
434 list_del(&page
->lru
);
435 h
->free_huge_pages
--;
436 h
->free_huge_pages_node
[nid
]--;
443 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
444 struct vm_area_struct
*vma
,
445 unsigned long address
, int avoid_reserve
)
448 struct page
*page
= NULL
;
449 struct mempolicy
*mpol
;
450 nodemask_t
*nodemask
;
451 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
452 htlb_alloc_mask
, &mpol
, &nodemask
);
457 * A child process with MAP_PRIVATE mappings created by their parent
458 * have no page reserves. This check ensures that reservations are
459 * not "stolen". The child may still get SIGKILLed
461 if (!vma_has_reserves(vma
) &&
462 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
465 /* If reserves cannot be used, ensure enough pages are in the pool */
466 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
469 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
470 MAX_NR_ZONES
- 1, nodemask
) {
471 nid
= zone_to_nid(zone
);
472 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
) &&
473 !list_empty(&h
->hugepage_freelists
[nid
])) {
474 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
476 list_del(&page
->lru
);
477 h
->free_huge_pages
--;
478 h
->free_huge_pages_node
[nid
]--;
481 decrement_hugepage_resv_vma(h
, vma
);
490 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
495 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
496 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
497 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
498 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
499 1 << PG_private
| 1<< PG_writeback
);
501 set_compound_page_dtor(page
, NULL
);
502 set_page_refcounted(page
);
503 arch_release_hugepage(page
);
504 __free_pages(page
, huge_page_order(h
));
507 struct hstate
*size_to_hstate(unsigned long size
)
512 if (huge_page_size(h
) == size
)
518 static void free_huge_page(struct page
*page
)
521 * Can't pass hstate in here because it is called from the
522 * compound page destructor.
524 struct hstate
*h
= page_hstate(page
);
525 int nid
= page_to_nid(page
);
526 struct address_space
*mapping
;
528 mapping
= (struct address_space
*) page_private(page
);
529 set_page_private(page
, 0);
530 BUG_ON(page_count(page
));
531 INIT_LIST_HEAD(&page
->lru
);
533 spin_lock(&hugetlb_lock
);
534 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
535 update_and_free_page(h
, page
);
536 h
->surplus_huge_pages
--;
537 h
->surplus_huge_pages_node
[nid
]--;
539 enqueue_huge_page(h
, page
);
541 spin_unlock(&hugetlb_lock
);
543 hugetlb_put_quota(mapping
, 1);
547 * Increment or decrement surplus_huge_pages. Keep node-specific counters
548 * balanced by operating on them in a round-robin fashion.
549 * Returns 1 if an adjustment was made.
551 static int adjust_pool_surplus(struct hstate
*h
, int delta
)
557 VM_BUG_ON(delta
!= -1 && delta
!= 1);
559 nid
= next_node(nid
, node_online_map
);
560 if (nid
== MAX_NUMNODES
)
561 nid
= first_node(node_online_map
);
563 /* To shrink on this node, there must be a surplus page */
564 if (delta
< 0 && !h
->surplus_huge_pages_node
[nid
])
566 /* Surplus cannot exceed the total number of pages */
567 if (delta
> 0 && h
->surplus_huge_pages_node
[nid
] >=
568 h
->nr_huge_pages_node
[nid
])
571 h
->surplus_huge_pages
+= delta
;
572 h
->surplus_huge_pages_node
[nid
] += delta
;
575 } while (nid
!= prev_nid
);
581 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
583 set_compound_page_dtor(page
, free_huge_page
);
584 spin_lock(&hugetlb_lock
);
586 h
->nr_huge_pages_node
[nid
]++;
587 spin_unlock(&hugetlb_lock
);
588 put_page(page
); /* free it into the hugepage allocator */
591 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
595 if (h
->order
>= MAX_ORDER
)
598 page
= alloc_pages_node(nid
,
599 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
600 __GFP_REPEAT
|__GFP_NOWARN
,
603 if (arch_prepare_hugepage(page
)) {
604 __free_pages(page
, huge_page_order(h
));
607 prep_new_huge_page(h
, page
, nid
);
614 * Use a helper variable to find the next node and then
615 * copy it back to hugetlb_next_nid afterwards:
616 * otherwise there's a window in which a racer might
617 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
618 * But we don't need to use a spin_lock here: it really
619 * doesn't matter if occasionally a racer chooses the
620 * same nid as we do. Move nid forward in the mask even
621 * if we just successfully allocated a hugepage so that
622 * the next caller gets hugepages on the next node.
624 static int hstate_next_node(struct hstate
*h
)
627 next_nid
= next_node(h
->hugetlb_next_nid
, node_online_map
);
628 if (next_nid
== MAX_NUMNODES
)
629 next_nid
= first_node(node_online_map
);
630 h
->hugetlb_next_nid
= next_nid
;
634 static int alloc_fresh_huge_page(struct hstate
*h
)
641 start_nid
= h
->hugetlb_next_nid
;
644 page
= alloc_fresh_huge_page_node(h
, h
->hugetlb_next_nid
);
647 next_nid
= hstate_next_node(h
);
648 } while (!page
&& h
->hugetlb_next_nid
!= start_nid
);
651 count_vm_event(HTLB_BUDDY_PGALLOC
);
653 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
658 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
659 struct vm_area_struct
*vma
, unsigned long address
)
664 if (h
->order
>= MAX_ORDER
)
668 * Assume we will successfully allocate the surplus page to
669 * prevent racing processes from causing the surplus to exceed
672 * This however introduces a different race, where a process B
673 * tries to grow the static hugepage pool while alloc_pages() is
674 * called by process A. B will only examine the per-node
675 * counters in determining if surplus huge pages can be
676 * converted to normal huge pages in adjust_pool_surplus(). A
677 * won't be able to increment the per-node counter, until the
678 * lock is dropped by B, but B doesn't drop hugetlb_lock until
679 * no more huge pages can be converted from surplus to normal
680 * state (and doesn't try to convert again). Thus, we have a
681 * case where a surplus huge page exists, the pool is grown, and
682 * the surplus huge page still exists after, even though it
683 * should just have been converted to a normal huge page. This
684 * does not leak memory, though, as the hugepage will be freed
685 * once it is out of use. It also does not allow the counters to
686 * go out of whack in adjust_pool_surplus() as we don't modify
687 * the node values until we've gotten the hugepage and only the
688 * per-node value is checked there.
690 spin_lock(&hugetlb_lock
);
691 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
692 spin_unlock(&hugetlb_lock
);
696 h
->surplus_huge_pages
++;
698 spin_unlock(&hugetlb_lock
);
700 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
701 __GFP_REPEAT
|__GFP_NOWARN
,
704 if (page
&& arch_prepare_hugepage(page
)) {
705 __free_pages(page
, huge_page_order(h
));
709 spin_lock(&hugetlb_lock
);
712 * This page is now managed by the hugetlb allocator and has
713 * no users -- drop the buddy allocator's reference.
715 put_page_testzero(page
);
716 VM_BUG_ON(page_count(page
));
717 nid
= page_to_nid(page
);
718 set_compound_page_dtor(page
, free_huge_page
);
720 * We incremented the global counters already
722 h
->nr_huge_pages_node
[nid
]++;
723 h
->surplus_huge_pages_node
[nid
]++;
724 __count_vm_event(HTLB_BUDDY_PGALLOC
);
727 h
->surplus_huge_pages
--;
728 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
730 spin_unlock(&hugetlb_lock
);
736 * Increase the hugetlb pool such that it can accomodate a reservation
739 static int gather_surplus_pages(struct hstate
*h
, int delta
)
741 struct list_head surplus_list
;
742 struct page
*page
, *tmp
;
744 int needed
, allocated
;
746 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
748 h
->resv_huge_pages
+= delta
;
753 INIT_LIST_HEAD(&surplus_list
);
757 spin_unlock(&hugetlb_lock
);
758 for (i
= 0; i
< needed
; i
++) {
759 page
= alloc_buddy_huge_page(h
, NULL
, 0);
762 * We were not able to allocate enough pages to
763 * satisfy the entire reservation so we free what
764 * we've allocated so far.
766 spin_lock(&hugetlb_lock
);
771 list_add(&page
->lru
, &surplus_list
);
776 * After retaking hugetlb_lock, we need to recalculate 'needed'
777 * because either resv_huge_pages or free_huge_pages may have changed.
779 spin_lock(&hugetlb_lock
);
780 needed
= (h
->resv_huge_pages
+ delta
) -
781 (h
->free_huge_pages
+ allocated
);
786 * The surplus_list now contains _at_least_ the number of extra pages
787 * needed to accomodate the reservation. Add the appropriate number
788 * of pages to the hugetlb pool and free the extras back to the buddy
789 * allocator. Commit the entire reservation here to prevent another
790 * process from stealing the pages as they are added to the pool but
791 * before they are reserved.
794 h
->resv_huge_pages
+= delta
;
797 /* Free the needed pages to the hugetlb pool */
798 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
801 list_del(&page
->lru
);
802 enqueue_huge_page(h
, page
);
805 /* Free unnecessary surplus pages to the buddy allocator */
806 if (!list_empty(&surplus_list
)) {
807 spin_unlock(&hugetlb_lock
);
808 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
809 list_del(&page
->lru
);
811 * The page has a reference count of zero already, so
812 * call free_huge_page directly instead of using
813 * put_page. This must be done with hugetlb_lock
814 * unlocked which is safe because free_huge_page takes
815 * hugetlb_lock before deciding how to free the page.
817 free_huge_page(page
);
819 spin_lock(&hugetlb_lock
);
826 * When releasing a hugetlb pool reservation, any surplus pages that were
827 * allocated to satisfy the reservation must be explicitly freed if they were
830 static void return_unused_surplus_pages(struct hstate
*h
,
831 unsigned long unused_resv_pages
)
835 unsigned long nr_pages
;
838 * We want to release as many surplus pages as possible, spread
839 * evenly across all nodes. Iterate across all nodes until we
840 * can no longer free unreserved surplus pages. This occurs when
841 * the nodes with surplus pages have no free pages.
843 unsigned long remaining_iterations
= num_online_nodes();
845 /* Uncommit the reservation */
846 h
->resv_huge_pages
-= unused_resv_pages
;
848 /* Cannot return gigantic pages currently */
849 if (h
->order
>= MAX_ORDER
)
852 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
854 while (remaining_iterations
-- && nr_pages
) {
855 nid
= next_node(nid
, node_online_map
);
856 if (nid
== MAX_NUMNODES
)
857 nid
= first_node(node_online_map
);
859 if (!h
->surplus_huge_pages_node
[nid
])
862 if (!list_empty(&h
->hugepage_freelists
[nid
])) {
863 page
= list_entry(h
->hugepage_freelists
[nid
].next
,
865 list_del(&page
->lru
);
866 update_and_free_page(h
, page
);
867 h
->free_huge_pages
--;
868 h
->free_huge_pages_node
[nid
]--;
869 h
->surplus_huge_pages
--;
870 h
->surplus_huge_pages_node
[nid
]--;
872 remaining_iterations
= num_online_nodes();
878 * Determine if the huge page at addr within the vma has an associated
879 * reservation. Where it does not we will need to logically increase
880 * reservation and actually increase quota before an allocation can occur.
881 * Where any new reservation would be required the reservation change is
882 * prepared, but not committed. Once the page has been quota'd allocated
883 * an instantiated the change should be committed via vma_commit_reservation.
884 * No action is required on failure.
886 static int vma_needs_reservation(struct hstate
*h
,
887 struct vm_area_struct
*vma
, unsigned long addr
)
889 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
890 struct inode
*inode
= mapping
->host
;
892 if (vma
->vm_flags
& VM_SHARED
) {
893 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
894 return region_chg(&inode
->i_mapping
->private_list
,
897 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
902 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
903 struct resv_map
*reservations
= vma_resv_map(vma
);
905 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
911 static void vma_commit_reservation(struct hstate
*h
,
912 struct vm_area_struct
*vma
, unsigned long addr
)
914 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
915 struct inode
*inode
= mapping
->host
;
917 if (vma
->vm_flags
& VM_SHARED
) {
918 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
919 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
921 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
922 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
923 struct resv_map
*reservations
= vma_resv_map(vma
);
925 /* Mark this page used in the map. */
926 region_add(&reservations
->regions
, idx
, idx
+ 1);
930 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
931 unsigned long addr
, int avoid_reserve
)
933 struct hstate
*h
= hstate_vma(vma
);
935 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
936 struct inode
*inode
= mapping
->host
;
940 * Processes that did not create the mapping will have no reserves and
941 * will not have accounted against quota. Check that the quota can be
942 * made before satisfying the allocation
943 * MAP_NORESERVE mappings may also need pages and quota allocated
944 * if no reserve mapping overlaps.
946 chg
= vma_needs_reservation(h
, vma
, addr
);
950 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
951 return ERR_PTR(-ENOSPC
);
953 spin_lock(&hugetlb_lock
);
954 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
955 spin_unlock(&hugetlb_lock
);
958 page
= alloc_buddy_huge_page(h
, vma
, addr
);
960 hugetlb_put_quota(inode
->i_mapping
, chg
);
961 return ERR_PTR(-VM_FAULT_OOM
);
965 set_page_refcounted(page
);
966 set_page_private(page
, (unsigned long) mapping
);
968 vma_commit_reservation(h
, vma
, addr
);
973 __attribute__((weak
)) int alloc_bootmem_huge_page(struct hstate
*h
)
975 struct huge_bootmem_page
*m
;
976 int nr_nodes
= nodes_weight(node_online_map
);
981 addr
= __alloc_bootmem_node_nopanic(
982 NODE_DATA(h
->hugetlb_next_nid
),
983 huge_page_size(h
), huge_page_size(h
), 0);
987 * Use the beginning of the huge page to store the
988 * huge_bootmem_page struct (until gather_bootmem
989 * puts them into the mem_map).
1001 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1002 /* Put them into a private list first because mem_map is not up yet */
1003 list_add(&m
->list
, &huge_boot_pages
);
1008 /* Put bootmem huge pages into the standard lists after mem_map is up */
1009 static void __init
gather_bootmem_prealloc(void)
1011 struct huge_bootmem_page
*m
;
1013 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1014 struct page
*page
= virt_to_page(m
);
1015 struct hstate
*h
= m
->hstate
;
1016 __ClearPageReserved(page
);
1017 WARN_ON(page_count(page
) != 1);
1018 prep_compound_page(page
, h
->order
);
1019 prep_new_huge_page(h
, page
, page_to_nid(page
));
1023 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1027 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1028 if (h
->order
>= MAX_ORDER
) {
1029 if (!alloc_bootmem_huge_page(h
))
1031 } else if (!alloc_fresh_huge_page(h
))
1034 h
->max_huge_pages
= i
;
1037 static void __init
hugetlb_init_hstates(void)
1041 for_each_hstate(h
) {
1042 /* oversize hugepages were init'ed in early boot */
1043 if (h
->order
< MAX_ORDER
)
1044 hugetlb_hstate_alloc_pages(h
);
1048 static char * __init
memfmt(char *buf
, unsigned long n
)
1050 if (n
>= (1UL << 30))
1051 sprintf(buf
, "%lu GB", n
>> 30);
1052 else if (n
>= (1UL << 20))
1053 sprintf(buf
, "%lu MB", n
>> 20);
1055 sprintf(buf
, "%lu KB", n
>> 10);
1059 static void __init
report_hugepages(void)
1063 for_each_hstate(h
) {
1065 printk(KERN_INFO
"HugeTLB registered %s page size, "
1066 "pre-allocated %ld pages\n",
1067 memfmt(buf
, huge_page_size(h
)),
1068 h
->free_huge_pages
);
1072 #ifdef CONFIG_HIGHMEM
1073 static void try_to_free_low(struct hstate
*h
, unsigned long count
)
1077 if (h
->order
>= MAX_ORDER
)
1080 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
1081 struct page
*page
, *next
;
1082 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1083 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1084 if (count
>= h
->nr_huge_pages
)
1086 if (PageHighMem(page
))
1088 list_del(&page
->lru
);
1089 update_and_free_page(h
, page
);
1090 h
->free_huge_pages
--;
1091 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1096 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
)
1101 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1102 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
)
1104 unsigned long min_count
, ret
;
1106 if (h
->order
>= MAX_ORDER
)
1107 return h
->max_huge_pages
;
1110 * Increase the pool size
1111 * First take pages out of surplus state. Then make up the
1112 * remaining difference by allocating fresh huge pages.
1114 * We might race with alloc_buddy_huge_page() here and be unable
1115 * to convert a surplus huge page to a normal huge page. That is
1116 * not critical, though, it just means the overall size of the
1117 * pool might be one hugepage larger than it needs to be, but
1118 * within all the constraints specified by the sysctls.
1120 spin_lock(&hugetlb_lock
);
1121 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1122 if (!adjust_pool_surplus(h
, -1))
1126 while (count
> persistent_huge_pages(h
)) {
1128 * If this allocation races such that we no longer need the
1129 * page, free_huge_page will handle it by freeing the page
1130 * and reducing the surplus.
1132 spin_unlock(&hugetlb_lock
);
1133 ret
= alloc_fresh_huge_page(h
);
1134 spin_lock(&hugetlb_lock
);
1141 * Decrease the pool size
1142 * First return free pages to the buddy allocator (being careful
1143 * to keep enough around to satisfy reservations). Then place
1144 * pages into surplus state as needed so the pool will shrink
1145 * to the desired size as pages become free.
1147 * By placing pages into the surplus state independent of the
1148 * overcommit value, we are allowing the surplus pool size to
1149 * exceed overcommit. There are few sane options here. Since
1150 * alloc_buddy_huge_page() is checking the global counter,
1151 * though, we'll note that we're not allowed to exceed surplus
1152 * and won't grow the pool anywhere else. Not until one of the
1153 * sysctls are changed, or the surplus pages go out of use.
1155 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1156 min_count
= max(count
, min_count
);
1157 try_to_free_low(h
, min_count
);
1158 while (min_count
< persistent_huge_pages(h
)) {
1159 struct page
*page
= dequeue_huge_page(h
);
1162 update_and_free_page(h
, page
);
1164 while (count
< persistent_huge_pages(h
)) {
1165 if (!adjust_pool_surplus(h
, 1))
1169 ret
= persistent_huge_pages(h
);
1170 spin_unlock(&hugetlb_lock
);
1174 #define HSTATE_ATTR_RO(_name) \
1175 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1177 #define HSTATE_ATTR(_name) \
1178 static struct kobj_attribute _name##_attr = \
1179 __ATTR(_name, 0644, _name##_show, _name##_store)
1181 static struct kobject
*hugepages_kobj
;
1182 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1184 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
)
1187 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1188 if (hstate_kobjs
[i
] == kobj
)
1194 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1195 struct kobj_attribute
*attr
, char *buf
)
1197 struct hstate
*h
= kobj_to_hstate(kobj
);
1198 return sprintf(buf
, "%lu\n", h
->nr_huge_pages
);
1200 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1201 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1204 unsigned long input
;
1205 struct hstate
*h
= kobj_to_hstate(kobj
);
1207 err
= strict_strtoul(buf
, 10, &input
);
1211 h
->max_huge_pages
= set_max_huge_pages(h
, input
);
1215 HSTATE_ATTR(nr_hugepages
);
1217 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1218 struct kobj_attribute
*attr
, char *buf
)
1220 struct hstate
*h
= kobj_to_hstate(kobj
);
1221 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1223 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1224 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1227 unsigned long input
;
1228 struct hstate
*h
= kobj_to_hstate(kobj
);
1230 err
= strict_strtoul(buf
, 10, &input
);
1234 spin_lock(&hugetlb_lock
);
1235 h
->nr_overcommit_huge_pages
= input
;
1236 spin_unlock(&hugetlb_lock
);
1240 HSTATE_ATTR(nr_overcommit_hugepages
);
1242 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1243 struct kobj_attribute
*attr
, char *buf
)
1245 struct hstate
*h
= kobj_to_hstate(kobj
);
1246 return sprintf(buf
, "%lu\n", h
->free_huge_pages
);
1248 HSTATE_ATTR_RO(free_hugepages
);
1250 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1251 struct kobj_attribute
*attr
, char *buf
)
1253 struct hstate
*h
= kobj_to_hstate(kobj
);
1254 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1256 HSTATE_ATTR_RO(resv_hugepages
);
1258 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1259 struct kobj_attribute
*attr
, char *buf
)
1261 struct hstate
*h
= kobj_to_hstate(kobj
);
1262 return sprintf(buf
, "%lu\n", h
->surplus_huge_pages
);
1264 HSTATE_ATTR_RO(surplus_hugepages
);
1266 static struct attribute
*hstate_attrs
[] = {
1267 &nr_hugepages_attr
.attr
,
1268 &nr_overcommit_hugepages_attr
.attr
,
1269 &free_hugepages_attr
.attr
,
1270 &resv_hugepages_attr
.attr
,
1271 &surplus_hugepages_attr
.attr
,
1275 static struct attribute_group hstate_attr_group
= {
1276 .attrs
= hstate_attrs
,
1279 static int __init
hugetlb_sysfs_add_hstate(struct hstate
*h
)
1283 hstate_kobjs
[h
- hstates
] = kobject_create_and_add(h
->name
,
1285 if (!hstate_kobjs
[h
- hstates
])
1288 retval
= sysfs_create_group(hstate_kobjs
[h
- hstates
],
1289 &hstate_attr_group
);
1291 kobject_put(hstate_kobjs
[h
- hstates
]);
1296 static void __init
hugetlb_sysfs_init(void)
1301 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1302 if (!hugepages_kobj
)
1305 for_each_hstate(h
) {
1306 err
= hugetlb_sysfs_add_hstate(h
);
1308 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1313 static void __exit
hugetlb_exit(void)
1317 for_each_hstate(h
) {
1318 kobject_put(hstate_kobjs
[h
- hstates
]);
1321 kobject_put(hugepages_kobj
);
1323 module_exit(hugetlb_exit
);
1325 static int __init
hugetlb_init(void)
1327 /* Some platform decide whether they support huge pages at boot
1328 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1329 * there is no such support
1331 if (HPAGE_SHIFT
== 0)
1334 if (!size_to_hstate(default_hstate_size
)) {
1335 default_hstate_size
= HPAGE_SIZE
;
1336 if (!size_to_hstate(default_hstate_size
))
1337 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1339 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1340 if (default_hstate_max_huge_pages
)
1341 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1343 hugetlb_init_hstates();
1345 gather_bootmem_prealloc();
1349 hugetlb_sysfs_init();
1353 module_init(hugetlb_init
);
1355 /* Should be called on processing a hugepagesz=... option */
1356 void __init
hugetlb_add_hstate(unsigned order
)
1361 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1362 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1365 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1367 h
= &hstates
[max_hstate
++];
1369 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1370 h
->nr_huge_pages
= 0;
1371 h
->free_huge_pages
= 0;
1372 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1373 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1374 h
->hugetlb_next_nid
= first_node(node_online_map
);
1375 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1376 huge_page_size(h
)/1024);
1381 static int __init
hugetlb_nrpages_setup(char *s
)
1384 static unsigned long *last_mhp
;
1387 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1388 * so this hugepages= parameter goes to the "default hstate".
1391 mhp
= &default_hstate_max_huge_pages
;
1393 mhp
= &parsed_hstate
->max_huge_pages
;
1395 if (mhp
== last_mhp
) {
1396 printk(KERN_WARNING
"hugepages= specified twice without "
1397 "interleaving hugepagesz=, ignoring\n");
1401 if (sscanf(s
, "%lu", mhp
) <= 0)
1405 * Global state is always initialized later in hugetlb_init.
1406 * But we need to allocate >= MAX_ORDER hstates here early to still
1407 * use the bootmem allocator.
1409 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1410 hugetlb_hstate_alloc_pages(parsed_hstate
);
1416 __setup("hugepages=", hugetlb_nrpages_setup
);
1418 static int __init
hugetlb_default_setup(char *s
)
1420 default_hstate_size
= memparse(s
, &s
);
1423 __setup("default_hugepagesz=", hugetlb_default_setup
);
1425 static unsigned int cpuset_mems_nr(unsigned int *array
)
1428 unsigned int nr
= 0;
1430 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1436 #ifdef CONFIG_SYSCTL
1437 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1438 struct file
*file
, void __user
*buffer
,
1439 size_t *length
, loff_t
*ppos
)
1441 struct hstate
*h
= &default_hstate
;
1445 tmp
= h
->max_huge_pages
;
1448 table
->maxlen
= sizeof(unsigned long);
1449 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1452 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
);
1457 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1458 struct file
*file
, void __user
*buffer
,
1459 size_t *length
, loff_t
*ppos
)
1461 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
1462 if (hugepages_treat_as_movable
)
1463 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1465 htlb_alloc_mask
= GFP_HIGHUSER
;
1469 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1470 struct file
*file
, void __user
*buffer
,
1471 size_t *length
, loff_t
*ppos
)
1473 struct hstate
*h
= &default_hstate
;
1477 tmp
= h
->nr_overcommit_huge_pages
;
1480 table
->maxlen
= sizeof(unsigned long);
1481 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
1484 spin_lock(&hugetlb_lock
);
1485 h
->nr_overcommit_huge_pages
= tmp
;
1486 spin_unlock(&hugetlb_lock
);
1492 #endif /* CONFIG_SYSCTL */
1494 void hugetlb_report_meminfo(struct seq_file
*m
)
1496 struct hstate
*h
= &default_hstate
;
1498 "HugePages_Total: %5lu\n"
1499 "HugePages_Free: %5lu\n"
1500 "HugePages_Rsvd: %5lu\n"
1501 "HugePages_Surp: %5lu\n"
1502 "Hugepagesize: %8lu kB\n",
1506 h
->surplus_huge_pages
,
1507 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1510 int hugetlb_report_node_meminfo(int nid
, char *buf
)
1512 struct hstate
*h
= &default_hstate
;
1514 "Node %d HugePages_Total: %5u\n"
1515 "Node %d HugePages_Free: %5u\n"
1516 "Node %d HugePages_Surp: %5u\n",
1517 nid
, h
->nr_huge_pages_node
[nid
],
1518 nid
, h
->free_huge_pages_node
[nid
],
1519 nid
, h
->surplus_huge_pages_node
[nid
]);
1522 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1523 unsigned long hugetlb_total_pages(void)
1525 struct hstate
*h
= &default_hstate
;
1526 return h
->nr_huge_pages
* pages_per_huge_page(h
);
1529 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
1533 spin_lock(&hugetlb_lock
);
1535 * When cpuset is configured, it breaks the strict hugetlb page
1536 * reservation as the accounting is done on a global variable. Such
1537 * reservation is completely rubbish in the presence of cpuset because
1538 * the reservation is not checked against page availability for the
1539 * current cpuset. Application can still potentially OOM'ed by kernel
1540 * with lack of free htlb page in cpuset that the task is in.
1541 * Attempt to enforce strict accounting with cpuset is almost
1542 * impossible (or too ugly) because cpuset is too fluid that
1543 * task or memory node can be dynamically moved between cpusets.
1545 * The change of semantics for shared hugetlb mapping with cpuset is
1546 * undesirable. However, in order to preserve some of the semantics,
1547 * we fall back to check against current free page availability as
1548 * a best attempt and hopefully to minimize the impact of changing
1549 * semantics that cpuset has.
1552 if (gather_surplus_pages(h
, delta
) < 0)
1555 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
1556 return_unused_surplus_pages(h
, delta
);
1563 return_unused_surplus_pages(h
, (unsigned long) -delta
);
1566 spin_unlock(&hugetlb_lock
);
1570 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
1572 struct resv_map
*reservations
= vma_resv_map(vma
);
1575 * This new VMA should share its siblings reservation map if present.
1576 * The VMA will only ever have a valid reservation map pointer where
1577 * it is being copied for another still existing VMA. As that VMA
1578 * has a reference to the reservation map it cannot dissappear until
1579 * after this open call completes. It is therefore safe to take a
1580 * new reference here without additional locking.
1583 kref_get(&reservations
->refs
);
1586 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
1588 struct hstate
*h
= hstate_vma(vma
);
1589 struct resv_map
*reservations
= vma_resv_map(vma
);
1590 unsigned long reserve
;
1591 unsigned long start
;
1595 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
1596 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
1598 reserve
= (end
- start
) -
1599 region_count(&reservations
->regions
, start
, end
);
1601 kref_put(&reservations
->refs
, resv_map_release
);
1604 hugetlb_acct_memory(h
, -reserve
);
1605 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
1611 * We cannot handle pagefaults against hugetlb pages at all. They cause
1612 * handle_mm_fault() to try to instantiate regular-sized pages in the
1613 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
1616 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1622 struct vm_operations_struct hugetlb_vm_ops
= {
1623 .fault
= hugetlb_vm_op_fault
,
1624 .open
= hugetlb_vm_op_open
,
1625 .close
= hugetlb_vm_op_close
,
1628 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
1635 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
1637 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
1639 entry
= pte_mkyoung(entry
);
1640 entry
= pte_mkhuge(entry
);
1645 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
1646 unsigned long address
, pte_t
*ptep
)
1650 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
1651 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
1652 update_mmu_cache(vma
, address
, entry
);
1657 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
1658 struct vm_area_struct
*vma
)
1660 pte_t
*src_pte
, *dst_pte
, entry
;
1661 struct page
*ptepage
;
1664 struct hstate
*h
= hstate_vma(vma
);
1665 unsigned long sz
= huge_page_size(h
);
1667 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
1669 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
1670 src_pte
= huge_pte_offset(src
, addr
);
1673 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
1677 /* If the pagetables are shared don't copy or take references */
1678 if (dst_pte
== src_pte
)
1681 spin_lock(&dst
->page_table_lock
);
1682 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
1683 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
1685 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
1686 entry
= huge_ptep_get(src_pte
);
1687 ptepage
= pte_page(entry
);
1689 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
1691 spin_unlock(&src
->page_table_lock
);
1692 spin_unlock(&dst
->page_table_lock
);
1700 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1701 unsigned long end
, struct page
*ref_page
)
1703 struct mm_struct
*mm
= vma
->vm_mm
;
1704 unsigned long address
;
1709 struct hstate
*h
= hstate_vma(vma
);
1710 unsigned long sz
= huge_page_size(h
);
1713 * A page gathering list, protected by per file i_mmap_lock. The
1714 * lock is used to avoid list corruption from multiple unmapping
1715 * of the same page since we are using page->lru.
1717 LIST_HEAD(page_list
);
1719 WARN_ON(!is_vm_hugetlb_page(vma
));
1720 BUG_ON(start
& ~huge_page_mask(h
));
1721 BUG_ON(end
& ~huge_page_mask(h
));
1723 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1724 spin_lock(&mm
->page_table_lock
);
1725 for (address
= start
; address
< end
; address
+= sz
) {
1726 ptep
= huge_pte_offset(mm
, address
);
1730 if (huge_pmd_unshare(mm
, &address
, ptep
))
1734 * If a reference page is supplied, it is because a specific
1735 * page is being unmapped, not a range. Ensure the page we
1736 * are about to unmap is the actual page of interest.
1739 pte
= huge_ptep_get(ptep
);
1740 if (huge_pte_none(pte
))
1742 page
= pte_page(pte
);
1743 if (page
!= ref_page
)
1747 * Mark the VMA as having unmapped its page so that
1748 * future faults in this VMA will fail rather than
1749 * looking like data was lost
1751 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
1754 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
1755 if (huge_pte_none(pte
))
1758 page
= pte_page(pte
);
1760 set_page_dirty(page
);
1761 list_add(&page
->lru
, &page_list
);
1763 spin_unlock(&mm
->page_table_lock
);
1764 flush_tlb_range(vma
, start
, end
);
1765 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1766 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
1767 list_del(&page
->lru
);
1772 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
1773 unsigned long end
, struct page
*ref_page
)
1775 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1776 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
1777 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
1781 * This is called when the original mapper is failing to COW a MAP_PRIVATE
1782 * mappping it owns the reserve page for. The intention is to unmap the page
1783 * from other VMAs and let the children be SIGKILLed if they are faulting the
1786 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1787 struct page
*page
, unsigned long address
)
1789 struct vm_area_struct
*iter_vma
;
1790 struct address_space
*mapping
;
1791 struct prio_tree_iter iter
;
1795 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1796 * from page cache lookup which is in HPAGE_SIZE units.
1798 address
= address
& huge_page_mask(hstate_vma(vma
));
1799 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
1800 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
1801 mapping
= (struct address_space
*)page_private(page
);
1803 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1804 /* Do not unmap the current VMA */
1805 if (iter_vma
== vma
)
1809 * Unmap the page from other VMAs without their own reserves.
1810 * They get marked to be SIGKILLed if they fault in these
1811 * areas. This is because a future no-page fault on this VMA
1812 * could insert a zeroed page instead of the data existing
1813 * from the time of fork. This would look like data corruption
1815 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
1816 unmap_hugepage_range(iter_vma
,
1817 address
, address
+ HPAGE_SIZE
,
1824 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1825 unsigned long address
, pte_t
*ptep
, pte_t pte
,
1826 struct page
*pagecache_page
)
1828 struct hstate
*h
= hstate_vma(vma
);
1829 struct page
*old_page
, *new_page
;
1831 int outside_reserve
= 0;
1833 old_page
= pte_page(pte
);
1836 /* If no-one else is actually using this page, avoid the copy
1837 * and just make the page writable */
1838 avoidcopy
= (page_count(old_page
) == 1);
1840 set_huge_ptep_writable(vma
, address
, ptep
);
1845 * If the process that created a MAP_PRIVATE mapping is about to
1846 * perform a COW due to a shared page count, attempt to satisfy
1847 * the allocation without using the existing reserves. The pagecache
1848 * page is used to determine if the reserve at this address was
1849 * consumed or not. If reserves were used, a partial faulted mapping
1850 * at the time of fork() could consume its reserves on COW instead
1851 * of the full address range.
1853 if (!(vma
->vm_flags
& VM_SHARED
) &&
1854 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
1855 old_page
!= pagecache_page
)
1856 outside_reserve
= 1;
1858 page_cache_get(old_page
);
1859 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
1861 if (IS_ERR(new_page
)) {
1862 page_cache_release(old_page
);
1865 * If a process owning a MAP_PRIVATE mapping fails to COW,
1866 * it is due to references held by a child and an insufficient
1867 * huge page pool. To guarantee the original mappers
1868 * reliability, unmap the page from child processes. The child
1869 * may get SIGKILLed if it later faults.
1871 if (outside_reserve
) {
1872 BUG_ON(huge_pte_none(pte
));
1873 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
1874 BUG_ON(page_count(old_page
) != 1);
1875 BUG_ON(huge_pte_none(pte
));
1876 goto retry_avoidcopy
;
1881 return -PTR_ERR(new_page
);
1884 spin_unlock(&mm
->page_table_lock
);
1885 copy_huge_page(new_page
, old_page
, address
, vma
);
1886 __SetPageUptodate(new_page
);
1887 spin_lock(&mm
->page_table_lock
);
1889 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
1890 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
1892 huge_ptep_clear_flush(vma
, address
, ptep
);
1893 set_huge_pte_at(mm
, address
, ptep
,
1894 make_huge_pte(vma
, new_page
, 1));
1895 /* Make the old page be freed below */
1896 new_page
= old_page
;
1898 page_cache_release(new_page
);
1899 page_cache_release(old_page
);
1903 /* Return the pagecache page at a given address within a VMA */
1904 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
1905 struct vm_area_struct
*vma
, unsigned long address
)
1907 struct address_space
*mapping
;
1910 mapping
= vma
->vm_file
->f_mapping
;
1911 idx
= vma_hugecache_offset(h
, vma
, address
);
1913 return find_lock_page(mapping
, idx
);
1916 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1917 unsigned long address
, pte_t
*ptep
, int write_access
)
1919 struct hstate
*h
= hstate_vma(vma
);
1920 int ret
= VM_FAULT_SIGBUS
;
1924 struct address_space
*mapping
;
1928 * Currently, we are forced to kill the process in the event the
1929 * original mapper has unmapped pages from the child due to a failed
1930 * COW. Warn that such a situation has occured as it may not be obvious
1932 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
1934 "PID %d killed due to inadequate hugepage pool\n",
1939 mapping
= vma
->vm_file
->f_mapping
;
1940 idx
= vma_hugecache_offset(h
, vma
, address
);
1943 * Use page lock to guard against racing truncation
1944 * before we get page_table_lock.
1947 page
= find_lock_page(mapping
, idx
);
1949 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1952 page
= alloc_huge_page(vma
, address
, 0);
1954 ret
= -PTR_ERR(page
);
1957 clear_huge_page(page
, address
, huge_page_size(h
));
1958 __SetPageUptodate(page
);
1960 if (vma
->vm_flags
& VM_SHARED
) {
1962 struct inode
*inode
= mapping
->host
;
1964 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
1972 spin_lock(&inode
->i_lock
);
1973 inode
->i_blocks
+= blocks_per_huge_page(h
);
1974 spin_unlock(&inode
->i_lock
);
1980 * If we are going to COW a private mapping later, we examine the
1981 * pending reservations for this page now. This will ensure that
1982 * any allocations necessary to record that reservation occur outside
1985 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
))
1986 if (vma_needs_reservation(h
, vma
, address
) < 0) {
1988 goto backout_unlocked
;
1991 spin_lock(&mm
->page_table_lock
);
1992 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
1997 if (!huge_pte_none(huge_ptep_get(ptep
)))
2000 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2001 && (vma
->vm_flags
& VM_SHARED
)));
2002 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2004 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
2005 /* Optimization, do the COW without a second fault */
2006 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2009 spin_unlock(&mm
->page_table_lock
);
2015 spin_unlock(&mm
->page_table_lock
);
2022 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2023 unsigned long address
, int write_access
)
2028 struct page
*pagecache_page
= NULL
;
2029 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2030 struct hstate
*h
= hstate_vma(vma
);
2032 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2034 return VM_FAULT_OOM
;
2037 * Serialize hugepage allocation and instantiation, so that we don't
2038 * get spurious allocation failures if two CPUs race to instantiate
2039 * the same page in the page cache.
2041 mutex_lock(&hugetlb_instantiation_mutex
);
2042 entry
= huge_ptep_get(ptep
);
2043 if (huge_pte_none(entry
)) {
2044 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
2051 * If we are going to COW the mapping later, we examine the pending
2052 * reservations for this page now. This will ensure that any
2053 * allocations necessary to record that reservation occur outside the
2054 * spinlock. For private mappings, we also lookup the pagecache
2055 * page now as it is used to determine if a reservation has been
2058 if (write_access
&& !pte_write(entry
)) {
2059 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2064 if (!(vma
->vm_flags
& VM_SHARED
))
2065 pagecache_page
= hugetlbfs_pagecache_page(h
,
2069 spin_lock(&mm
->page_table_lock
);
2070 /* Check for a racing update before calling hugetlb_cow */
2071 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2072 goto out_page_table_lock
;
2076 if (!pte_write(entry
)) {
2077 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2079 goto out_page_table_lock
;
2081 entry
= pte_mkdirty(entry
);
2083 entry
= pte_mkyoung(entry
);
2084 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, write_access
))
2085 update_mmu_cache(vma
, address
, entry
);
2087 out_page_table_lock
:
2088 spin_unlock(&mm
->page_table_lock
);
2090 if (pagecache_page
) {
2091 unlock_page(pagecache_page
);
2092 put_page(pagecache_page
);
2096 mutex_unlock(&hugetlb_instantiation_mutex
);
2101 /* Can be overriden by architectures */
2102 __attribute__((weak
)) struct page
*
2103 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2104 pud_t
*pud
, int write
)
2110 static int huge_zeropage_ok(pte_t
*ptep
, int write
, int shared
)
2112 if (!ptep
|| write
|| shared
)
2115 return huge_pte_none(huge_ptep_get(ptep
));
2118 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2119 struct page
**pages
, struct vm_area_struct
**vmas
,
2120 unsigned long *position
, int *length
, int i
,
2123 unsigned long pfn_offset
;
2124 unsigned long vaddr
= *position
;
2125 int remainder
= *length
;
2126 struct hstate
*h
= hstate_vma(vma
);
2127 int zeropage_ok
= 0;
2128 int shared
= vma
->vm_flags
& VM_SHARED
;
2130 spin_lock(&mm
->page_table_lock
);
2131 while (vaddr
< vma
->vm_end
&& remainder
) {
2136 * Some archs (sparc64, sh*) have multiple pte_ts to
2137 * each hugepage. We have to make * sure we get the
2138 * first, for the page indexing below to work.
2140 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2141 if (huge_zeropage_ok(pte
, write
, shared
))
2145 (huge_pte_none(huge_ptep_get(pte
)) && !zeropage_ok
) ||
2146 (write
&& !pte_write(huge_ptep_get(pte
)))) {
2149 spin_unlock(&mm
->page_table_lock
);
2150 ret
= hugetlb_fault(mm
, vma
, vaddr
, write
);
2151 spin_lock(&mm
->page_table_lock
);
2152 if (!(ret
& VM_FAULT_ERROR
))
2161 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2162 page
= pte_page(huge_ptep_get(pte
));
2166 pages
[i
] = ZERO_PAGE(0);
2168 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2179 if (vaddr
< vma
->vm_end
&& remainder
&&
2180 pfn_offset
< pages_per_huge_page(h
)) {
2182 * We use pfn_offset to avoid touching the pageframes
2183 * of this compound page.
2188 spin_unlock(&mm
->page_table_lock
);
2189 *length
= remainder
;
2195 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2196 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2198 struct mm_struct
*mm
= vma
->vm_mm
;
2199 unsigned long start
= address
;
2202 struct hstate
*h
= hstate_vma(vma
);
2204 BUG_ON(address
>= end
);
2205 flush_cache_range(vma
, address
, end
);
2207 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2208 spin_lock(&mm
->page_table_lock
);
2209 for (; address
< end
; address
+= huge_page_size(h
)) {
2210 ptep
= huge_pte_offset(mm
, address
);
2213 if (huge_pmd_unshare(mm
, &address
, ptep
))
2215 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2216 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2217 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2218 set_huge_pte_at(mm
, address
, ptep
, pte
);
2221 spin_unlock(&mm
->page_table_lock
);
2222 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2224 flush_tlb_range(vma
, start
, end
);
2227 int hugetlb_reserve_pages(struct inode
*inode
,
2229 struct vm_area_struct
*vma
)
2232 struct hstate
*h
= hstate_inode(inode
);
2234 if (vma
&& vma
->vm_flags
& VM_NORESERVE
)
2238 * Shared mappings base their reservation on the number of pages that
2239 * are already allocated on behalf of the file. Private mappings need
2240 * to reserve the full area even if read-only as mprotect() may be
2241 * called to make the mapping read-write. Assume !vma is a shm mapping
2243 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
2244 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2246 struct resv_map
*resv_map
= resv_map_alloc();
2252 set_vma_resv_map(vma
, resv_map
);
2253 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2259 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2261 ret
= hugetlb_acct_memory(h
, chg
);
2263 hugetlb_put_quota(inode
->i_mapping
, chg
);
2266 if (!vma
|| vma
->vm_flags
& VM_SHARED
)
2267 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2271 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2273 struct hstate
*h
= hstate_inode(inode
);
2274 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2276 spin_lock(&inode
->i_lock
);
2277 inode
->i_blocks
-= blocks_per_huge_page(h
);
2278 spin_unlock(&inode
->i_lock
);
2280 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2281 hugetlb_acct_memory(h
, -(chg
- freed
));