2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
26 #include <asm/pgtable.h>
29 #include <linux/hugetlb.h>
30 #include <linux/node.h>
33 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
34 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
35 unsigned long hugepages_treat_as_movable
;
37 static int max_hstate
;
38 unsigned int default_hstate_idx
;
39 struct hstate hstates
[HUGE_MAX_HSTATE
];
41 __initdata
LIST_HEAD(huge_boot_pages
);
43 /* for command line parsing */
44 static struct hstate
* __initdata parsed_hstate
;
45 static unsigned long __initdata default_hstate_max_huge_pages
;
46 static unsigned long __initdata default_hstate_size
;
48 #define for_each_hstate(h) \
49 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
52 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
54 static DEFINE_SPINLOCK(hugetlb_lock
);
57 * Region tracking -- allows tracking of reservations and instantiated pages
58 * across the pages in a mapping.
60 * The region data structures are protected by a combination of the mmap_sem
61 * and the hugetlb_instantion_mutex. To access or modify a region the caller
62 * must either hold the mmap_sem for write, or the mmap_sem for read and
63 * the hugetlb_instantiation mutex:
65 * down_write(&mm->mmap_sem);
67 * down_read(&mm->mmap_sem);
68 * mutex_lock(&hugetlb_instantiation_mutex);
71 struct list_head link
;
76 static long region_add(struct list_head
*head
, long f
, long t
)
78 struct file_region
*rg
, *nrg
, *trg
;
80 /* Locate the region we are either in or before. */
81 list_for_each_entry(rg
, head
, link
)
85 /* Round our left edge to the current segment if it encloses us. */
89 /* Check for and consume any regions we now overlap with. */
91 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
92 if (&rg
->link
== head
)
97 /* If this area reaches higher then extend our area to
98 * include it completely. If this is not the first area
99 * which we intend to reuse, free it. */
112 static long region_chg(struct list_head
*head
, long f
, long t
)
114 struct file_region
*rg
, *nrg
;
117 /* Locate the region we are before or in. */
118 list_for_each_entry(rg
, head
, link
)
122 /* If we are below the current region then a new region is required.
123 * Subtle, allocate a new region at the position but make it zero
124 * size such that we can guarantee to record the reservation. */
125 if (&rg
->link
== head
|| t
< rg
->from
) {
126 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
131 INIT_LIST_HEAD(&nrg
->link
);
132 list_add(&nrg
->link
, rg
->link
.prev
);
137 /* Round our left edge to the current segment if it encloses us. */
142 /* Check for and consume any regions we now overlap with. */
143 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
144 if (&rg
->link
== head
)
149 /* We overlap with this area, if it extends further than
150 * us then we must extend ourselves. Account for its
151 * existing reservation. */
156 chg
-= rg
->to
- rg
->from
;
161 static long region_truncate(struct list_head
*head
, long end
)
163 struct file_region
*rg
, *trg
;
166 /* Locate the region we are either in or before. */
167 list_for_each_entry(rg
, head
, link
)
170 if (&rg
->link
== head
)
173 /* If we are in the middle of a region then adjust it. */
174 if (end
> rg
->from
) {
177 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
180 /* Drop any remaining regions. */
181 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
182 if (&rg
->link
== head
)
184 chg
+= rg
->to
- rg
->from
;
191 static long region_count(struct list_head
*head
, long f
, long t
)
193 struct file_region
*rg
;
196 /* Locate each segment we overlap with, and count that overlap. */
197 list_for_each_entry(rg
, head
, link
) {
206 seg_from
= max(rg
->from
, f
);
207 seg_to
= min(rg
->to
, t
);
209 chg
+= seg_to
- seg_from
;
216 * Convert the address within this vma to the page offset within
217 * the mapping, in pagecache page units; huge pages here.
219 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
220 struct vm_area_struct
*vma
, unsigned long address
)
222 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
223 (vma
->vm_pgoff
>> huge_page_order(h
));
226 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
227 unsigned long address
)
229 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
233 * Return the size of the pages allocated when backing a VMA. In the majority
234 * cases this will be same size as used by the page table entries.
236 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
238 struct hstate
*hstate
;
240 if (!is_vm_hugetlb_page(vma
))
243 hstate
= hstate_vma(vma
);
245 return 1UL << (hstate
->order
+ PAGE_SHIFT
);
247 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
250 * Return the page size being used by the MMU to back a VMA. In the majority
251 * of cases, the page size used by the kernel matches the MMU size. On
252 * architectures where it differs, an architecture-specific version of this
253 * function is required.
255 #ifndef vma_mmu_pagesize
256 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
258 return vma_kernel_pagesize(vma
);
263 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
264 * bits of the reservation map pointer, which are always clear due to
267 #define HPAGE_RESV_OWNER (1UL << 0)
268 #define HPAGE_RESV_UNMAPPED (1UL << 1)
269 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
272 * These helpers are used to track how many pages are reserved for
273 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
274 * is guaranteed to have their future faults succeed.
276 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
277 * the reserve counters are updated with the hugetlb_lock held. It is safe
278 * to reset the VMA at fork() time as it is not in use yet and there is no
279 * chance of the global counters getting corrupted as a result of the values.
281 * The private mapping reservation is represented in a subtly different
282 * manner to a shared mapping. A shared mapping has a region map associated
283 * with the underlying file, this region map represents the backing file
284 * pages which have ever had a reservation assigned which this persists even
285 * after the page is instantiated. A private mapping has a region map
286 * associated with the original mmap which is attached to all VMAs which
287 * reference it, this region map represents those offsets which have consumed
288 * reservation ie. where pages have been instantiated.
290 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
292 return (unsigned long)vma
->vm_private_data
;
295 static void set_vma_private_data(struct vm_area_struct
*vma
,
298 vma
->vm_private_data
= (void *)value
;
303 struct list_head regions
;
306 static struct resv_map
*resv_map_alloc(void)
308 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
312 kref_init(&resv_map
->refs
);
313 INIT_LIST_HEAD(&resv_map
->regions
);
318 static void resv_map_release(struct kref
*ref
)
320 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
322 /* Clear out any active regions before we release the map. */
323 region_truncate(&resv_map
->regions
, 0);
327 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
329 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
330 if (!(vma
->vm_flags
& VM_MAYSHARE
))
331 return (struct resv_map
*)(get_vma_private_data(vma
) &
336 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
338 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
339 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
341 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
342 HPAGE_RESV_MASK
) | (unsigned long)map
);
345 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
347 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
348 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
350 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
353 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
355 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
357 return (get_vma_private_data(vma
) & flag
) != 0;
360 /* Decrement the reserved pages in the hugepage pool by one */
361 static void decrement_hugepage_resv_vma(struct hstate
*h
,
362 struct vm_area_struct
*vma
)
364 if (vma
->vm_flags
& VM_NORESERVE
)
367 if (vma
->vm_flags
& VM_MAYSHARE
) {
368 /* Shared mappings always use reserves */
369 h
->resv_huge_pages
--;
370 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
372 * Only the process that called mmap() has reserves for
375 h
->resv_huge_pages
--;
379 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
380 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
382 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
383 if (!(vma
->vm_flags
& VM_MAYSHARE
))
384 vma
->vm_private_data
= (void *)0;
387 /* Returns true if the VMA has associated reserve pages */
388 static int vma_has_reserves(struct vm_area_struct
*vma
)
390 if (vma
->vm_flags
& VM_MAYSHARE
)
392 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
397 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
400 struct hstate
*h
= page_hstate(src
);
401 struct page
*dst_base
= dst
;
402 struct page
*src_base
= src
;
404 for (i
= 0; i
< pages_per_huge_page(h
); ) {
406 copy_highpage(dst
, src
);
409 dst
= mem_map_next(dst
, dst_base
, i
);
410 src
= mem_map_next(src
, src_base
, i
);
414 void copy_huge_page(struct page
*dst
, struct page
*src
)
417 struct hstate
*h
= page_hstate(src
);
419 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
420 copy_gigantic_page(dst
, src
);
425 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
427 copy_highpage(dst
+ i
, src
+ i
);
431 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
433 int nid
= page_to_nid(page
);
434 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
435 h
->free_huge_pages
++;
436 h
->free_huge_pages_node
[nid
]++;
439 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
443 if (list_empty(&h
->hugepage_freelists
[nid
]))
445 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
446 list_del(&page
->lru
);
447 set_page_refcounted(page
);
448 h
->free_huge_pages
--;
449 h
->free_huge_pages_node
[nid
]--;
453 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
454 struct vm_area_struct
*vma
,
455 unsigned long address
, int avoid_reserve
)
457 struct page
*page
= NULL
;
458 struct mempolicy
*mpol
;
459 nodemask_t
*nodemask
;
460 struct zonelist
*zonelist
;
465 zonelist
= huge_zonelist(vma
, address
,
466 htlb_alloc_mask
, &mpol
, &nodemask
);
468 * A child process with MAP_PRIVATE mappings created by their parent
469 * have no page reserves. This check ensures that reservations are
470 * not "stolen". The child may still get SIGKILLed
472 if (!vma_has_reserves(vma
) &&
473 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
476 /* If reserves cannot be used, ensure enough pages are in the pool */
477 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
480 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
481 MAX_NR_ZONES
- 1, nodemask
) {
482 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
483 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
486 decrement_hugepage_resv_vma(h
, vma
);
497 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
501 VM_BUG_ON(h
->order
>= MAX_ORDER
);
504 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
505 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
506 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
507 1 << PG_referenced
| 1 << PG_dirty
|
508 1 << PG_active
| 1 << PG_reserved
|
509 1 << PG_private
| 1 << PG_writeback
);
511 set_compound_page_dtor(page
, NULL
);
512 set_page_refcounted(page
);
513 arch_release_hugepage(page
);
514 __free_pages(page
, huge_page_order(h
));
517 struct hstate
*size_to_hstate(unsigned long size
)
522 if (huge_page_size(h
) == size
)
528 static void free_huge_page(struct page
*page
)
531 * Can't pass hstate in here because it is called from the
532 * compound page destructor.
534 struct hstate
*h
= page_hstate(page
);
535 int nid
= page_to_nid(page
);
536 struct address_space
*mapping
;
538 mapping
= (struct address_space
*) page_private(page
);
539 set_page_private(page
, 0);
540 page
->mapping
= NULL
;
541 BUG_ON(page_count(page
));
542 BUG_ON(page_mapcount(page
));
543 INIT_LIST_HEAD(&page
->lru
);
545 spin_lock(&hugetlb_lock
);
546 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
547 update_and_free_page(h
, page
);
548 h
->surplus_huge_pages
--;
549 h
->surplus_huge_pages_node
[nid
]--;
551 enqueue_huge_page(h
, page
);
553 spin_unlock(&hugetlb_lock
);
555 hugetlb_put_quota(mapping
, 1);
558 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
560 set_compound_page_dtor(page
, free_huge_page
);
561 spin_lock(&hugetlb_lock
);
563 h
->nr_huge_pages_node
[nid
]++;
564 spin_unlock(&hugetlb_lock
);
565 put_page(page
); /* free it into the hugepage allocator */
568 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
571 int nr_pages
= 1 << order
;
572 struct page
*p
= page
+ 1;
574 /* we rely on prep_new_huge_page to set the destructor */
575 set_compound_order(page
, order
);
577 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
579 set_page_count(p
, 0);
580 p
->first_page
= page
;
584 int PageHuge(struct page
*page
)
586 compound_page_dtor
*dtor
;
588 if (!PageCompound(page
))
591 page
= compound_head(page
);
592 dtor
= get_compound_page_dtor(page
);
594 return dtor
== free_huge_page
;
596 EXPORT_SYMBOL_GPL(PageHuge
);
598 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
602 if (h
->order
>= MAX_ORDER
)
605 page
= alloc_pages_exact_node(nid
,
606 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
607 __GFP_REPEAT
|__GFP_NOWARN
,
610 if (arch_prepare_hugepage(page
)) {
611 __free_pages(page
, huge_page_order(h
));
614 prep_new_huge_page(h
, page
, nid
);
621 * common helper functions for hstate_next_node_to_{alloc|free}.
622 * We may have allocated or freed a huge page based on a different
623 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
624 * be outside of *nodes_allowed. Ensure that we use an allowed
625 * node for alloc or free.
627 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
629 nid
= next_node(nid
, *nodes_allowed
);
630 if (nid
== MAX_NUMNODES
)
631 nid
= first_node(*nodes_allowed
);
632 VM_BUG_ON(nid
>= MAX_NUMNODES
);
637 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
639 if (!node_isset(nid
, *nodes_allowed
))
640 nid
= next_node_allowed(nid
, nodes_allowed
);
645 * returns the previously saved node ["this node"] from which to
646 * allocate a persistent huge page for the pool and advance the
647 * next node from which to allocate, handling wrap at end of node
650 static int hstate_next_node_to_alloc(struct hstate
*h
,
651 nodemask_t
*nodes_allowed
)
655 VM_BUG_ON(!nodes_allowed
);
657 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
658 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
663 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
670 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
671 next_nid
= start_nid
;
674 page
= alloc_fresh_huge_page_node(h
, next_nid
);
679 next_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
680 } while (next_nid
!= start_nid
);
683 count_vm_event(HTLB_BUDDY_PGALLOC
);
685 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
691 * helper for free_pool_huge_page() - return the previously saved
692 * node ["this node"] from which to free a huge page. Advance the
693 * next node id whether or not we find a free huge page to free so
694 * that the next attempt to free addresses the next node.
696 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
700 VM_BUG_ON(!nodes_allowed
);
702 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
703 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
709 * Free huge page from pool from next node to free.
710 * Attempt to keep persistent huge pages more or less
711 * balanced over allowed nodes.
712 * Called with hugetlb_lock locked.
714 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
721 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
722 next_nid
= start_nid
;
726 * If we're returning unused surplus pages, only examine
727 * nodes with surplus pages.
729 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
730 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
732 list_entry(h
->hugepage_freelists
[next_nid
].next
,
734 list_del(&page
->lru
);
735 h
->free_huge_pages
--;
736 h
->free_huge_pages_node
[next_nid
]--;
738 h
->surplus_huge_pages
--;
739 h
->surplus_huge_pages_node
[next_nid
]--;
741 update_and_free_page(h
, page
);
745 next_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
746 } while (next_nid
!= start_nid
);
751 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
756 if (h
->order
>= MAX_ORDER
)
760 * Assume we will successfully allocate the surplus page to
761 * prevent racing processes from causing the surplus to exceed
764 * This however introduces a different race, where a process B
765 * tries to grow the static hugepage pool while alloc_pages() is
766 * called by process A. B will only examine the per-node
767 * counters in determining if surplus huge pages can be
768 * converted to normal huge pages in adjust_pool_surplus(). A
769 * won't be able to increment the per-node counter, until the
770 * lock is dropped by B, but B doesn't drop hugetlb_lock until
771 * no more huge pages can be converted from surplus to normal
772 * state (and doesn't try to convert again). Thus, we have a
773 * case where a surplus huge page exists, the pool is grown, and
774 * the surplus huge page still exists after, even though it
775 * should just have been converted to a normal huge page. This
776 * does not leak memory, though, as the hugepage will be freed
777 * once it is out of use. It also does not allow the counters to
778 * go out of whack in adjust_pool_surplus() as we don't modify
779 * the node values until we've gotten the hugepage and only the
780 * per-node value is checked there.
782 spin_lock(&hugetlb_lock
);
783 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
784 spin_unlock(&hugetlb_lock
);
788 h
->surplus_huge_pages
++;
790 spin_unlock(&hugetlb_lock
);
792 if (nid
== NUMA_NO_NODE
)
793 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
794 __GFP_REPEAT
|__GFP_NOWARN
,
797 page
= alloc_pages_exact_node(nid
,
798 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
799 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
801 if (page
&& arch_prepare_hugepage(page
)) {
802 __free_pages(page
, huge_page_order(h
));
806 spin_lock(&hugetlb_lock
);
808 r_nid
= page_to_nid(page
);
809 set_compound_page_dtor(page
, free_huge_page
);
811 * We incremented the global counters already
813 h
->nr_huge_pages_node
[r_nid
]++;
814 h
->surplus_huge_pages_node
[r_nid
]++;
815 __count_vm_event(HTLB_BUDDY_PGALLOC
);
818 h
->surplus_huge_pages
--;
819 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
821 spin_unlock(&hugetlb_lock
);
827 * This allocation function is useful in the context where vma is irrelevant.
828 * E.g. soft-offlining uses this function because it only cares physical
829 * address of error page.
831 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
835 spin_lock(&hugetlb_lock
);
836 page
= dequeue_huge_page_node(h
, nid
);
837 spin_unlock(&hugetlb_lock
);
840 page
= alloc_buddy_huge_page(h
, nid
);
846 * Increase the hugetlb pool such that it can accommodate a reservation
849 static int gather_surplus_pages(struct hstate
*h
, int delta
)
851 struct list_head surplus_list
;
852 struct page
*page
, *tmp
;
854 int needed
, allocated
;
855 bool alloc_ok
= true;
857 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
859 h
->resv_huge_pages
+= delta
;
864 INIT_LIST_HEAD(&surplus_list
);
868 spin_unlock(&hugetlb_lock
);
869 for (i
= 0; i
< needed
; i
++) {
870 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
875 list_add(&page
->lru
, &surplus_list
);
880 * After retaking hugetlb_lock, we need to recalculate 'needed'
881 * because either resv_huge_pages or free_huge_pages may have changed.
883 spin_lock(&hugetlb_lock
);
884 needed
= (h
->resv_huge_pages
+ delta
) -
885 (h
->free_huge_pages
+ allocated
);
890 * We were not able to allocate enough pages to
891 * satisfy the entire reservation so we free what
892 * we've allocated so far.
897 * The surplus_list now contains _at_least_ the number of extra pages
898 * needed to accommodate the reservation. Add the appropriate number
899 * of pages to the hugetlb pool and free the extras back to the buddy
900 * allocator. Commit the entire reservation here to prevent another
901 * process from stealing the pages as they are added to the pool but
902 * before they are reserved.
905 h
->resv_huge_pages
+= delta
;
908 /* Free the needed pages to the hugetlb pool */
909 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
912 list_del(&page
->lru
);
914 * This page is now managed by the hugetlb allocator and has
915 * no users -- drop the buddy allocator's reference.
917 put_page_testzero(page
);
918 VM_BUG_ON(page_count(page
));
919 enqueue_huge_page(h
, page
);
922 spin_unlock(&hugetlb_lock
);
924 /* Free unnecessary surplus pages to the buddy allocator */
925 if (!list_empty(&surplus_list
)) {
926 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
927 list_del(&page
->lru
);
931 spin_lock(&hugetlb_lock
);
937 * When releasing a hugetlb pool reservation, any surplus pages that were
938 * allocated to satisfy the reservation must be explicitly freed if they were
940 * Called with hugetlb_lock held.
942 static void return_unused_surplus_pages(struct hstate
*h
,
943 unsigned long unused_resv_pages
)
945 unsigned long nr_pages
;
947 /* Uncommit the reservation */
948 h
->resv_huge_pages
-= unused_resv_pages
;
950 /* Cannot return gigantic pages currently */
951 if (h
->order
>= MAX_ORDER
)
954 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
957 * We want to release as many surplus pages as possible, spread
958 * evenly across all nodes with memory. Iterate across these nodes
959 * until we can no longer free unreserved surplus pages. This occurs
960 * when the nodes with surplus pages have no free pages.
961 * free_pool_huge_page() will balance the the freed pages across the
962 * on-line nodes with memory and will handle the hstate accounting.
965 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
971 * Determine if the huge page at addr within the vma has an associated
972 * reservation. Where it does not we will need to logically increase
973 * reservation and actually increase quota before an allocation can occur.
974 * Where any new reservation would be required the reservation change is
975 * prepared, but not committed. Once the page has been quota'd allocated
976 * an instantiated the change should be committed via vma_commit_reservation.
977 * No action is required on failure.
979 static long vma_needs_reservation(struct hstate
*h
,
980 struct vm_area_struct
*vma
, unsigned long addr
)
982 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
983 struct inode
*inode
= mapping
->host
;
985 if (vma
->vm_flags
& VM_MAYSHARE
) {
986 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
987 return region_chg(&inode
->i_mapping
->private_list
,
990 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
995 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
996 struct resv_map
*reservations
= vma_resv_map(vma
);
998 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1004 static void vma_commit_reservation(struct hstate
*h
,
1005 struct vm_area_struct
*vma
, unsigned long addr
)
1007 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1008 struct inode
*inode
= mapping
->host
;
1010 if (vma
->vm_flags
& VM_MAYSHARE
) {
1011 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1012 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1014 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1015 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1016 struct resv_map
*reservations
= vma_resv_map(vma
);
1018 /* Mark this page used in the map. */
1019 region_add(&reservations
->regions
, idx
, idx
+ 1);
1023 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1024 unsigned long addr
, int avoid_reserve
)
1026 struct hstate
*h
= hstate_vma(vma
);
1028 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1029 struct inode
*inode
= mapping
->host
;
1033 * Processes that did not create the mapping will have no reserves and
1034 * will not have accounted against quota. Check that the quota can be
1035 * made before satisfying the allocation
1036 * MAP_NORESERVE mappings may also need pages and quota allocated
1037 * if no reserve mapping overlaps.
1039 chg
= vma_needs_reservation(h
, vma
, addr
);
1041 return ERR_PTR(-VM_FAULT_OOM
);
1043 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1044 return ERR_PTR(-VM_FAULT_SIGBUS
);
1046 spin_lock(&hugetlb_lock
);
1047 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1048 spin_unlock(&hugetlb_lock
);
1051 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1053 hugetlb_put_quota(inode
->i_mapping
, chg
);
1054 return ERR_PTR(-VM_FAULT_SIGBUS
);
1058 set_page_private(page
, (unsigned long) mapping
);
1060 vma_commit_reservation(h
, vma
, addr
);
1065 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1067 struct huge_bootmem_page
*m
;
1068 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1073 addr
= __alloc_bootmem_node_nopanic(
1074 NODE_DATA(hstate_next_node_to_alloc(h
,
1075 &node_states
[N_HIGH_MEMORY
])),
1076 huge_page_size(h
), huge_page_size(h
), 0);
1080 * Use the beginning of the huge page to store the
1081 * huge_bootmem_page struct (until gather_bootmem
1082 * puts them into the mem_map).
1092 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1093 /* Put them into a private list first because mem_map is not up yet */
1094 list_add(&m
->list
, &huge_boot_pages
);
1099 static void prep_compound_huge_page(struct page
*page
, int order
)
1101 if (unlikely(order
> (MAX_ORDER
- 1)))
1102 prep_compound_gigantic_page(page
, order
);
1104 prep_compound_page(page
, order
);
1107 /* Put bootmem huge pages into the standard lists after mem_map is up */
1108 static void __init
gather_bootmem_prealloc(void)
1110 struct huge_bootmem_page
*m
;
1112 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1113 struct hstate
*h
= m
->hstate
;
1116 #ifdef CONFIG_HIGHMEM
1117 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1118 free_bootmem_late((unsigned long)m
,
1119 sizeof(struct huge_bootmem_page
));
1121 page
= virt_to_page(m
);
1123 __ClearPageReserved(page
);
1124 WARN_ON(page_count(page
) != 1);
1125 prep_compound_huge_page(page
, h
->order
);
1126 prep_new_huge_page(h
, page
, page_to_nid(page
));
1128 * If we had gigantic hugepages allocated at boot time, we need
1129 * to restore the 'stolen' pages to totalram_pages in order to
1130 * fix confusing memory reports from free(1) and another
1131 * side-effects, like CommitLimit going negative.
1133 if (h
->order
> (MAX_ORDER
- 1))
1134 totalram_pages
+= 1 << h
->order
;
1138 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1142 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1143 if (h
->order
>= MAX_ORDER
) {
1144 if (!alloc_bootmem_huge_page(h
))
1146 } else if (!alloc_fresh_huge_page(h
,
1147 &node_states
[N_HIGH_MEMORY
]))
1150 h
->max_huge_pages
= i
;
1153 static void __init
hugetlb_init_hstates(void)
1157 for_each_hstate(h
) {
1158 /* oversize hugepages were init'ed in early boot */
1159 if (h
->order
< MAX_ORDER
)
1160 hugetlb_hstate_alloc_pages(h
);
1164 static char * __init
memfmt(char *buf
, unsigned long n
)
1166 if (n
>= (1UL << 30))
1167 sprintf(buf
, "%lu GB", n
>> 30);
1168 else if (n
>= (1UL << 20))
1169 sprintf(buf
, "%lu MB", n
>> 20);
1171 sprintf(buf
, "%lu KB", n
>> 10);
1175 static void __init
report_hugepages(void)
1179 for_each_hstate(h
) {
1181 printk(KERN_INFO
"HugeTLB registered %s page size, "
1182 "pre-allocated %ld pages\n",
1183 memfmt(buf
, huge_page_size(h
)),
1184 h
->free_huge_pages
);
1188 #ifdef CONFIG_HIGHMEM
1189 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1190 nodemask_t
*nodes_allowed
)
1194 if (h
->order
>= MAX_ORDER
)
1197 for_each_node_mask(i
, *nodes_allowed
) {
1198 struct page
*page
, *next
;
1199 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1200 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1201 if (count
>= h
->nr_huge_pages
)
1203 if (PageHighMem(page
))
1205 list_del(&page
->lru
);
1206 update_and_free_page(h
, page
);
1207 h
->free_huge_pages
--;
1208 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1213 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1214 nodemask_t
*nodes_allowed
)
1220 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1221 * balanced by operating on them in a round-robin fashion.
1222 * Returns 1 if an adjustment was made.
1224 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1227 int start_nid
, next_nid
;
1230 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1233 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1235 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1236 next_nid
= start_nid
;
1242 * To shrink on this node, there must be a surplus page
1244 if (!h
->surplus_huge_pages_node
[nid
]) {
1245 next_nid
= hstate_next_node_to_alloc(h
,
1252 * Surplus cannot exceed the total number of pages
1254 if (h
->surplus_huge_pages_node
[nid
] >=
1255 h
->nr_huge_pages_node
[nid
]) {
1256 next_nid
= hstate_next_node_to_free(h
,
1262 h
->surplus_huge_pages
+= delta
;
1263 h
->surplus_huge_pages_node
[nid
] += delta
;
1266 } while (next_nid
!= start_nid
);
1271 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1272 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1273 nodemask_t
*nodes_allowed
)
1275 unsigned long min_count
, ret
;
1277 if (h
->order
>= MAX_ORDER
)
1278 return h
->max_huge_pages
;
1281 * Increase the pool size
1282 * First take pages out of surplus state. Then make up the
1283 * remaining difference by allocating fresh huge pages.
1285 * We might race with alloc_buddy_huge_page() here and be unable
1286 * to convert a surplus huge page to a normal huge page. That is
1287 * not critical, though, it just means the overall size of the
1288 * pool might be one hugepage larger than it needs to be, but
1289 * within all the constraints specified by the sysctls.
1291 spin_lock(&hugetlb_lock
);
1292 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1293 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1297 while (count
> persistent_huge_pages(h
)) {
1299 * If this allocation races such that we no longer need the
1300 * page, free_huge_page will handle it by freeing the page
1301 * and reducing the surplus.
1303 spin_unlock(&hugetlb_lock
);
1304 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1305 spin_lock(&hugetlb_lock
);
1309 /* Bail for signals. Probably ctrl-c from user */
1310 if (signal_pending(current
))
1315 * Decrease the pool size
1316 * First return free pages to the buddy allocator (being careful
1317 * to keep enough around to satisfy reservations). Then place
1318 * pages into surplus state as needed so the pool will shrink
1319 * to the desired size as pages become free.
1321 * By placing pages into the surplus state independent of the
1322 * overcommit value, we are allowing the surplus pool size to
1323 * exceed overcommit. There are few sane options here. Since
1324 * alloc_buddy_huge_page() is checking the global counter,
1325 * though, we'll note that we're not allowed to exceed surplus
1326 * and won't grow the pool anywhere else. Not until one of the
1327 * sysctls are changed, or the surplus pages go out of use.
1329 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1330 min_count
= max(count
, min_count
);
1331 try_to_free_low(h
, min_count
, nodes_allowed
);
1332 while (min_count
< persistent_huge_pages(h
)) {
1333 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1336 while (count
< persistent_huge_pages(h
)) {
1337 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1341 ret
= persistent_huge_pages(h
);
1342 spin_unlock(&hugetlb_lock
);
1346 #define HSTATE_ATTR_RO(_name) \
1347 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1349 #define HSTATE_ATTR(_name) \
1350 static struct kobj_attribute _name##_attr = \
1351 __ATTR(_name, 0644, _name##_show, _name##_store)
1353 static struct kobject
*hugepages_kobj
;
1354 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1356 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1358 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1362 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1363 if (hstate_kobjs
[i
] == kobj
) {
1365 *nidp
= NUMA_NO_NODE
;
1369 return kobj_to_node_hstate(kobj
, nidp
);
1372 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1373 struct kobj_attribute
*attr
, char *buf
)
1376 unsigned long nr_huge_pages
;
1379 h
= kobj_to_hstate(kobj
, &nid
);
1380 if (nid
== NUMA_NO_NODE
)
1381 nr_huge_pages
= h
->nr_huge_pages
;
1383 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1385 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1388 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1389 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1390 const char *buf
, size_t len
)
1394 unsigned long count
;
1396 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1398 err
= strict_strtoul(buf
, 10, &count
);
1402 h
= kobj_to_hstate(kobj
, &nid
);
1403 if (h
->order
>= MAX_ORDER
) {
1408 if (nid
== NUMA_NO_NODE
) {
1410 * global hstate attribute
1412 if (!(obey_mempolicy
&&
1413 init_nodemask_of_mempolicy(nodes_allowed
))) {
1414 NODEMASK_FREE(nodes_allowed
);
1415 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1417 } else if (nodes_allowed
) {
1419 * per node hstate attribute: adjust count to global,
1420 * but restrict alloc/free to the specified node.
1422 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1423 init_nodemask_of_node(nodes_allowed
, nid
);
1425 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1427 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1429 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1430 NODEMASK_FREE(nodes_allowed
);
1434 NODEMASK_FREE(nodes_allowed
);
1438 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1439 struct kobj_attribute
*attr
, char *buf
)
1441 return nr_hugepages_show_common(kobj
, attr
, buf
);
1444 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1445 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1447 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1449 HSTATE_ATTR(nr_hugepages
);
1454 * hstate attribute for optionally mempolicy-based constraint on persistent
1455 * huge page alloc/free.
1457 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1458 struct kobj_attribute
*attr
, char *buf
)
1460 return nr_hugepages_show_common(kobj
, attr
, buf
);
1463 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1464 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1466 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1468 HSTATE_ATTR(nr_hugepages_mempolicy
);
1472 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1473 struct kobj_attribute
*attr
, char *buf
)
1475 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1476 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1479 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1480 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1483 unsigned long input
;
1484 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1486 if (h
->order
>= MAX_ORDER
)
1489 err
= strict_strtoul(buf
, 10, &input
);
1493 spin_lock(&hugetlb_lock
);
1494 h
->nr_overcommit_huge_pages
= input
;
1495 spin_unlock(&hugetlb_lock
);
1499 HSTATE_ATTR(nr_overcommit_hugepages
);
1501 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1502 struct kobj_attribute
*attr
, char *buf
)
1505 unsigned long free_huge_pages
;
1508 h
= kobj_to_hstate(kobj
, &nid
);
1509 if (nid
== NUMA_NO_NODE
)
1510 free_huge_pages
= h
->free_huge_pages
;
1512 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1514 return sprintf(buf
, "%lu\n", free_huge_pages
);
1516 HSTATE_ATTR_RO(free_hugepages
);
1518 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1519 struct kobj_attribute
*attr
, char *buf
)
1521 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1522 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1524 HSTATE_ATTR_RO(resv_hugepages
);
1526 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1527 struct kobj_attribute
*attr
, char *buf
)
1530 unsigned long surplus_huge_pages
;
1533 h
= kobj_to_hstate(kobj
, &nid
);
1534 if (nid
== NUMA_NO_NODE
)
1535 surplus_huge_pages
= h
->surplus_huge_pages
;
1537 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1539 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1541 HSTATE_ATTR_RO(surplus_hugepages
);
1543 static struct attribute
*hstate_attrs
[] = {
1544 &nr_hugepages_attr
.attr
,
1545 &nr_overcommit_hugepages_attr
.attr
,
1546 &free_hugepages_attr
.attr
,
1547 &resv_hugepages_attr
.attr
,
1548 &surplus_hugepages_attr
.attr
,
1550 &nr_hugepages_mempolicy_attr
.attr
,
1555 static struct attribute_group hstate_attr_group
= {
1556 .attrs
= hstate_attrs
,
1559 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1560 struct kobject
**hstate_kobjs
,
1561 struct attribute_group
*hstate_attr_group
)
1564 int hi
= h
- hstates
;
1566 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1567 if (!hstate_kobjs
[hi
])
1570 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1572 kobject_put(hstate_kobjs
[hi
]);
1577 static void __init
hugetlb_sysfs_init(void)
1582 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1583 if (!hugepages_kobj
)
1586 for_each_hstate(h
) {
1587 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1588 hstate_kobjs
, &hstate_attr_group
);
1590 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1598 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1599 * with node devices in node_devices[] using a parallel array. The array
1600 * index of a node device or _hstate == node id.
1601 * This is here to avoid any static dependency of the node device driver, in
1602 * the base kernel, on the hugetlb module.
1604 struct node_hstate
{
1605 struct kobject
*hugepages_kobj
;
1606 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1608 struct node_hstate node_hstates
[MAX_NUMNODES
];
1611 * A subset of global hstate attributes for node devices
1613 static struct attribute
*per_node_hstate_attrs
[] = {
1614 &nr_hugepages_attr
.attr
,
1615 &free_hugepages_attr
.attr
,
1616 &surplus_hugepages_attr
.attr
,
1620 static struct attribute_group per_node_hstate_attr_group
= {
1621 .attrs
= per_node_hstate_attrs
,
1625 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1626 * Returns node id via non-NULL nidp.
1628 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1632 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1633 struct node_hstate
*nhs
= &node_hstates
[nid
];
1635 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1636 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1648 * Unregister hstate attributes from a single node device.
1649 * No-op if no hstate attributes attached.
1651 void hugetlb_unregister_node(struct node
*node
)
1654 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1656 if (!nhs
->hugepages_kobj
)
1657 return; /* no hstate attributes */
1660 if (nhs
->hstate_kobjs
[h
- hstates
]) {
1661 kobject_put(nhs
->hstate_kobjs
[h
- hstates
]);
1662 nhs
->hstate_kobjs
[h
- hstates
] = NULL
;
1665 kobject_put(nhs
->hugepages_kobj
);
1666 nhs
->hugepages_kobj
= NULL
;
1670 * hugetlb module exit: unregister hstate attributes from node devices
1673 static void hugetlb_unregister_all_nodes(void)
1678 * disable node device registrations.
1680 register_hugetlbfs_with_node(NULL
, NULL
);
1683 * remove hstate attributes from any nodes that have them.
1685 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1686 hugetlb_unregister_node(&node_devices
[nid
]);
1690 * Register hstate attributes for a single node device.
1691 * No-op if attributes already registered.
1693 void hugetlb_register_node(struct node
*node
)
1696 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1699 if (nhs
->hugepages_kobj
)
1700 return; /* already allocated */
1702 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1704 if (!nhs
->hugepages_kobj
)
1707 for_each_hstate(h
) {
1708 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1710 &per_node_hstate_attr_group
);
1712 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1714 h
->name
, node
->dev
.id
);
1715 hugetlb_unregister_node(node
);
1722 * hugetlb init time: register hstate attributes for all registered node
1723 * devices of nodes that have memory. All on-line nodes should have
1724 * registered their associated device by this time.
1726 static void hugetlb_register_all_nodes(void)
1730 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1731 struct node
*node
= &node_devices
[nid
];
1732 if (node
->dev
.id
== nid
)
1733 hugetlb_register_node(node
);
1737 * Let the node device driver know we're here so it can
1738 * [un]register hstate attributes on node hotplug.
1740 register_hugetlbfs_with_node(hugetlb_register_node
,
1741 hugetlb_unregister_node
);
1743 #else /* !CONFIG_NUMA */
1745 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1753 static void hugetlb_unregister_all_nodes(void) { }
1755 static void hugetlb_register_all_nodes(void) { }
1759 static void __exit
hugetlb_exit(void)
1763 hugetlb_unregister_all_nodes();
1765 for_each_hstate(h
) {
1766 kobject_put(hstate_kobjs
[h
- hstates
]);
1769 kobject_put(hugepages_kobj
);
1771 module_exit(hugetlb_exit
);
1773 static int __init
hugetlb_init(void)
1775 /* Some platform decide whether they support huge pages at boot
1776 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1777 * there is no such support
1779 if (HPAGE_SHIFT
== 0)
1782 if (!size_to_hstate(default_hstate_size
)) {
1783 default_hstate_size
= HPAGE_SIZE
;
1784 if (!size_to_hstate(default_hstate_size
))
1785 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1787 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1788 if (default_hstate_max_huge_pages
)
1789 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1791 hugetlb_init_hstates();
1793 gather_bootmem_prealloc();
1797 hugetlb_sysfs_init();
1799 hugetlb_register_all_nodes();
1803 module_init(hugetlb_init
);
1805 /* Should be called on processing a hugepagesz=... option */
1806 void __init
hugetlb_add_hstate(unsigned order
)
1811 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1812 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1815 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1817 h
= &hstates
[max_hstate
++];
1819 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1820 h
->nr_huge_pages
= 0;
1821 h
->free_huge_pages
= 0;
1822 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1823 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1824 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1825 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1826 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1827 huge_page_size(h
)/1024);
1832 static int __init
hugetlb_nrpages_setup(char *s
)
1835 static unsigned long *last_mhp
;
1838 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1839 * so this hugepages= parameter goes to the "default hstate".
1842 mhp
= &default_hstate_max_huge_pages
;
1844 mhp
= &parsed_hstate
->max_huge_pages
;
1846 if (mhp
== last_mhp
) {
1847 printk(KERN_WARNING
"hugepages= specified twice without "
1848 "interleaving hugepagesz=, ignoring\n");
1852 if (sscanf(s
, "%lu", mhp
) <= 0)
1856 * Global state is always initialized later in hugetlb_init.
1857 * But we need to allocate >= MAX_ORDER hstates here early to still
1858 * use the bootmem allocator.
1860 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1861 hugetlb_hstate_alloc_pages(parsed_hstate
);
1867 __setup("hugepages=", hugetlb_nrpages_setup
);
1869 static int __init
hugetlb_default_setup(char *s
)
1871 default_hstate_size
= memparse(s
, &s
);
1874 __setup("default_hugepagesz=", hugetlb_default_setup
);
1876 static unsigned int cpuset_mems_nr(unsigned int *array
)
1879 unsigned int nr
= 0;
1881 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1887 #ifdef CONFIG_SYSCTL
1888 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1889 struct ctl_table
*table
, int write
,
1890 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1892 struct hstate
*h
= &default_hstate
;
1896 tmp
= h
->max_huge_pages
;
1898 if (write
&& h
->order
>= MAX_ORDER
)
1902 table
->maxlen
= sizeof(unsigned long);
1903 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1908 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
1909 GFP_KERNEL
| __GFP_NORETRY
);
1910 if (!(obey_mempolicy
&&
1911 init_nodemask_of_mempolicy(nodes_allowed
))) {
1912 NODEMASK_FREE(nodes_allowed
);
1913 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1915 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
1917 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1918 NODEMASK_FREE(nodes_allowed
);
1924 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1925 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1928 return hugetlb_sysctl_handler_common(false, table
, write
,
1929 buffer
, length
, ppos
);
1933 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
1934 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1936 return hugetlb_sysctl_handler_common(true, table
, write
,
1937 buffer
, length
, ppos
);
1939 #endif /* CONFIG_NUMA */
1941 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1942 void __user
*buffer
,
1943 size_t *length
, loff_t
*ppos
)
1945 proc_dointvec(table
, write
, buffer
, length
, ppos
);
1946 if (hugepages_treat_as_movable
)
1947 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1949 htlb_alloc_mask
= GFP_HIGHUSER
;
1953 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1954 void __user
*buffer
,
1955 size_t *length
, loff_t
*ppos
)
1957 struct hstate
*h
= &default_hstate
;
1961 tmp
= h
->nr_overcommit_huge_pages
;
1963 if (write
&& h
->order
>= MAX_ORDER
)
1967 table
->maxlen
= sizeof(unsigned long);
1968 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1973 spin_lock(&hugetlb_lock
);
1974 h
->nr_overcommit_huge_pages
= tmp
;
1975 spin_unlock(&hugetlb_lock
);
1981 #endif /* CONFIG_SYSCTL */
1983 void hugetlb_report_meminfo(struct seq_file
*m
)
1985 struct hstate
*h
= &default_hstate
;
1987 "HugePages_Total: %5lu\n"
1988 "HugePages_Free: %5lu\n"
1989 "HugePages_Rsvd: %5lu\n"
1990 "HugePages_Surp: %5lu\n"
1991 "Hugepagesize: %8lu kB\n",
1995 h
->surplus_huge_pages
,
1996 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
1999 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2001 struct hstate
*h
= &default_hstate
;
2003 "Node %d HugePages_Total: %5u\n"
2004 "Node %d HugePages_Free: %5u\n"
2005 "Node %d HugePages_Surp: %5u\n",
2006 nid
, h
->nr_huge_pages_node
[nid
],
2007 nid
, h
->free_huge_pages_node
[nid
],
2008 nid
, h
->surplus_huge_pages_node
[nid
]);
2011 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2012 unsigned long hugetlb_total_pages(void)
2014 struct hstate
*h
= &default_hstate
;
2015 return h
->nr_huge_pages
* pages_per_huge_page(h
);
2018 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2022 spin_lock(&hugetlb_lock
);
2024 * When cpuset is configured, it breaks the strict hugetlb page
2025 * reservation as the accounting is done on a global variable. Such
2026 * reservation is completely rubbish in the presence of cpuset because
2027 * the reservation is not checked against page availability for the
2028 * current cpuset. Application can still potentially OOM'ed by kernel
2029 * with lack of free htlb page in cpuset that the task is in.
2030 * Attempt to enforce strict accounting with cpuset is almost
2031 * impossible (or too ugly) because cpuset is too fluid that
2032 * task or memory node can be dynamically moved between cpusets.
2034 * The change of semantics for shared hugetlb mapping with cpuset is
2035 * undesirable. However, in order to preserve some of the semantics,
2036 * we fall back to check against current free page availability as
2037 * a best attempt and hopefully to minimize the impact of changing
2038 * semantics that cpuset has.
2041 if (gather_surplus_pages(h
, delta
) < 0)
2044 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2045 return_unused_surplus_pages(h
, delta
);
2052 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2055 spin_unlock(&hugetlb_lock
);
2059 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2061 struct resv_map
*reservations
= vma_resv_map(vma
);
2064 * This new VMA should share its siblings reservation map if present.
2065 * The VMA will only ever have a valid reservation map pointer where
2066 * it is being copied for another still existing VMA. As that VMA
2067 * has a reference to the reservation map it cannot disappear until
2068 * after this open call completes. It is therefore safe to take a
2069 * new reference here without additional locking.
2072 kref_get(&reservations
->refs
);
2075 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2077 struct hstate
*h
= hstate_vma(vma
);
2078 struct resv_map
*reservations
= vma_resv_map(vma
);
2079 unsigned long reserve
;
2080 unsigned long start
;
2084 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2085 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2087 reserve
= (end
- start
) -
2088 region_count(&reservations
->regions
, start
, end
);
2090 kref_put(&reservations
->refs
, resv_map_release
);
2093 hugetlb_acct_memory(h
, -reserve
);
2094 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
2100 * We cannot handle pagefaults against hugetlb pages at all. They cause
2101 * handle_mm_fault() to try to instantiate regular-sized pages in the
2102 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2105 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2111 const struct vm_operations_struct hugetlb_vm_ops
= {
2112 .fault
= hugetlb_vm_op_fault
,
2113 .open
= hugetlb_vm_op_open
,
2114 .close
= hugetlb_vm_op_close
,
2117 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2124 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2126 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2128 entry
= pte_mkyoung(entry
);
2129 entry
= pte_mkhuge(entry
);
2134 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2135 unsigned long address
, pte_t
*ptep
)
2139 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2140 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2141 update_mmu_cache(vma
, address
, ptep
);
2145 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2146 struct vm_area_struct
*vma
)
2148 pte_t
*src_pte
, *dst_pte
, entry
;
2149 struct page
*ptepage
;
2152 struct hstate
*h
= hstate_vma(vma
);
2153 unsigned long sz
= huge_page_size(h
);
2155 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2157 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2158 src_pte
= huge_pte_offset(src
, addr
);
2161 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2165 /* If the pagetables are shared don't copy or take references */
2166 if (dst_pte
== src_pte
)
2169 spin_lock(&dst
->page_table_lock
);
2170 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2171 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2173 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2174 entry
= huge_ptep_get(src_pte
);
2175 ptepage
= pte_page(entry
);
2177 page_dup_rmap(ptepage
);
2178 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2180 spin_unlock(&src
->page_table_lock
);
2181 spin_unlock(&dst
->page_table_lock
);
2189 static int is_hugetlb_entry_migration(pte_t pte
)
2193 if (huge_pte_none(pte
) || pte_present(pte
))
2195 swp
= pte_to_swp_entry(pte
);
2196 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2202 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2206 if (huge_pte_none(pte
) || pte_present(pte
))
2208 swp
= pte_to_swp_entry(pte
);
2209 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2215 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2216 unsigned long end
, struct page
*ref_page
)
2218 struct mm_struct
*mm
= vma
->vm_mm
;
2219 unsigned long address
;
2224 struct hstate
*h
= hstate_vma(vma
);
2225 unsigned long sz
= huge_page_size(h
);
2228 * A page gathering list, protected by per file i_mmap_mutex. The
2229 * lock is used to avoid list corruption from multiple unmapping
2230 * of the same page since we are using page->lru.
2232 LIST_HEAD(page_list
);
2234 WARN_ON(!is_vm_hugetlb_page(vma
));
2235 BUG_ON(start
& ~huge_page_mask(h
));
2236 BUG_ON(end
& ~huge_page_mask(h
));
2238 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2239 spin_lock(&mm
->page_table_lock
);
2240 for (address
= start
; address
< end
; address
+= sz
) {
2241 ptep
= huge_pte_offset(mm
, address
);
2245 if (huge_pmd_unshare(mm
, &address
, ptep
))
2249 * If a reference page is supplied, it is because a specific
2250 * page is being unmapped, not a range. Ensure the page we
2251 * are about to unmap is the actual page of interest.
2254 pte
= huge_ptep_get(ptep
);
2255 if (huge_pte_none(pte
))
2257 page
= pte_page(pte
);
2258 if (page
!= ref_page
)
2262 * Mark the VMA as having unmapped its page so that
2263 * future faults in this VMA will fail rather than
2264 * looking like data was lost
2266 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2269 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2270 if (huge_pte_none(pte
))
2274 * HWPoisoned hugepage is already unmapped and dropped reference
2276 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
)))
2279 page
= pte_page(pte
);
2281 set_page_dirty(page
);
2282 list_add(&page
->lru
, &page_list
);
2284 /* Bail out after unmapping reference page if supplied */
2288 flush_tlb_range(vma
, start
, end
);
2289 spin_unlock(&mm
->page_table_lock
);
2290 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2291 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
2292 page_remove_rmap(page
);
2293 list_del(&page
->lru
);
2298 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2299 unsigned long end
, struct page
*ref_page
)
2301 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2302 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
2303 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2307 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2308 * mappping it owns the reserve page for. The intention is to unmap the page
2309 * from other VMAs and let the children be SIGKILLed if they are faulting the
2312 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2313 struct page
*page
, unsigned long address
)
2315 struct hstate
*h
= hstate_vma(vma
);
2316 struct vm_area_struct
*iter_vma
;
2317 struct address_space
*mapping
;
2318 struct prio_tree_iter iter
;
2322 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2323 * from page cache lookup which is in HPAGE_SIZE units.
2325 address
= address
& huge_page_mask(h
);
2326 pgoff
= vma_hugecache_offset(h
, vma
, address
);
2327 mapping
= (struct address_space
*)page_private(page
);
2330 * Take the mapping lock for the duration of the table walk. As
2331 * this mapping should be shared between all the VMAs,
2332 * __unmap_hugepage_range() is called as the lock is already held
2334 mutex_lock(&mapping
->i_mmap_mutex
);
2335 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2336 /* Do not unmap the current VMA */
2337 if (iter_vma
== vma
)
2341 * Unmap the page from other VMAs without their own reserves.
2342 * They get marked to be SIGKILLed if they fault in these
2343 * areas. This is because a future no-page fault on this VMA
2344 * could insert a zeroed page instead of the data existing
2345 * from the time of fork. This would look like data corruption
2347 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2348 __unmap_hugepage_range(iter_vma
,
2349 address
, address
+ huge_page_size(h
),
2352 mutex_unlock(&mapping
->i_mmap_mutex
);
2358 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2359 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2360 * cannot race with other handlers or page migration.
2361 * Keep the pte_same checks anyway to make transition from the mutex easier.
2363 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2364 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2365 struct page
*pagecache_page
)
2367 struct hstate
*h
= hstate_vma(vma
);
2368 struct page
*old_page
, *new_page
;
2370 int outside_reserve
= 0;
2372 old_page
= pte_page(pte
);
2375 /* If no-one else is actually using this page, avoid the copy
2376 * and just make the page writable */
2377 avoidcopy
= (page_mapcount(old_page
) == 1);
2379 if (PageAnon(old_page
))
2380 page_move_anon_rmap(old_page
, vma
, address
);
2381 set_huge_ptep_writable(vma
, address
, ptep
);
2386 * If the process that created a MAP_PRIVATE mapping is about to
2387 * perform a COW due to a shared page count, attempt to satisfy
2388 * the allocation without using the existing reserves. The pagecache
2389 * page is used to determine if the reserve at this address was
2390 * consumed or not. If reserves were used, a partial faulted mapping
2391 * at the time of fork() could consume its reserves on COW instead
2392 * of the full address range.
2394 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2395 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2396 old_page
!= pagecache_page
)
2397 outside_reserve
= 1;
2399 page_cache_get(old_page
);
2401 /* Drop page_table_lock as buddy allocator may be called */
2402 spin_unlock(&mm
->page_table_lock
);
2403 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2405 if (IS_ERR(new_page
)) {
2406 page_cache_release(old_page
);
2409 * If a process owning a MAP_PRIVATE mapping fails to COW,
2410 * it is due to references held by a child and an insufficient
2411 * huge page pool. To guarantee the original mappers
2412 * reliability, unmap the page from child processes. The child
2413 * may get SIGKILLed if it later faults.
2415 if (outside_reserve
) {
2416 BUG_ON(huge_pte_none(pte
));
2417 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2418 BUG_ON(page_count(old_page
) != 1);
2419 BUG_ON(huge_pte_none(pte
));
2420 spin_lock(&mm
->page_table_lock
);
2421 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2422 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2423 goto retry_avoidcopy
;
2425 * race occurs while re-acquiring page_table_lock, and
2433 /* Caller expects lock to be held */
2434 spin_lock(&mm
->page_table_lock
);
2435 return -PTR_ERR(new_page
);
2439 * When the original hugepage is shared one, it does not have
2440 * anon_vma prepared.
2442 if (unlikely(anon_vma_prepare(vma
))) {
2443 page_cache_release(new_page
);
2444 page_cache_release(old_page
);
2445 /* Caller expects lock to be held */
2446 spin_lock(&mm
->page_table_lock
);
2447 return VM_FAULT_OOM
;
2450 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2451 pages_per_huge_page(h
));
2452 __SetPageUptodate(new_page
);
2455 * Retake the page_table_lock to check for racing updates
2456 * before the page tables are altered
2458 spin_lock(&mm
->page_table_lock
);
2459 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2460 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2462 mmu_notifier_invalidate_range_start(mm
,
2463 address
& huge_page_mask(h
),
2464 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2465 huge_ptep_clear_flush(vma
, address
, ptep
);
2466 set_huge_pte_at(mm
, address
, ptep
,
2467 make_huge_pte(vma
, new_page
, 1));
2468 page_remove_rmap(old_page
);
2469 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2470 /* Make the old page be freed below */
2471 new_page
= old_page
;
2472 mmu_notifier_invalidate_range_end(mm
,
2473 address
& huge_page_mask(h
),
2474 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2476 page_cache_release(new_page
);
2477 page_cache_release(old_page
);
2481 /* Return the pagecache page at a given address within a VMA */
2482 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2483 struct vm_area_struct
*vma
, unsigned long address
)
2485 struct address_space
*mapping
;
2488 mapping
= vma
->vm_file
->f_mapping
;
2489 idx
= vma_hugecache_offset(h
, vma
, address
);
2491 return find_lock_page(mapping
, idx
);
2495 * Return whether there is a pagecache page to back given address within VMA.
2496 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2498 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2499 struct vm_area_struct
*vma
, unsigned long address
)
2501 struct address_space
*mapping
;
2505 mapping
= vma
->vm_file
->f_mapping
;
2506 idx
= vma_hugecache_offset(h
, vma
, address
);
2508 page
= find_get_page(mapping
, idx
);
2511 return page
!= NULL
;
2514 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2515 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2517 struct hstate
*h
= hstate_vma(vma
);
2518 int ret
= VM_FAULT_SIGBUS
;
2523 struct address_space
*mapping
;
2527 * Currently, we are forced to kill the process in the event the
2528 * original mapper has unmapped pages from the child due to a failed
2529 * COW. Warn that such a situation has occurred as it may not be obvious
2531 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2533 "PID %d killed due to inadequate hugepage pool\n",
2538 mapping
= vma
->vm_file
->f_mapping
;
2539 idx
= vma_hugecache_offset(h
, vma
, address
);
2542 * Use page lock to guard against racing truncation
2543 * before we get page_table_lock.
2546 page
= find_lock_page(mapping
, idx
);
2548 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2551 page
= alloc_huge_page(vma
, address
, 0);
2553 ret
= -PTR_ERR(page
);
2556 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2557 __SetPageUptodate(page
);
2559 if (vma
->vm_flags
& VM_MAYSHARE
) {
2561 struct inode
*inode
= mapping
->host
;
2563 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2571 spin_lock(&inode
->i_lock
);
2572 inode
->i_blocks
+= blocks_per_huge_page(h
);
2573 spin_unlock(&inode
->i_lock
);
2576 if (unlikely(anon_vma_prepare(vma
))) {
2578 goto backout_unlocked
;
2584 * If memory error occurs between mmap() and fault, some process
2585 * don't have hwpoisoned swap entry for errored virtual address.
2586 * So we need to block hugepage fault by PG_hwpoison bit check.
2588 if (unlikely(PageHWPoison(page
))) {
2589 ret
= VM_FAULT_HWPOISON
|
2590 VM_FAULT_SET_HINDEX(h
- hstates
);
2591 goto backout_unlocked
;
2596 * If we are going to COW a private mapping later, we examine the
2597 * pending reservations for this page now. This will ensure that
2598 * any allocations necessary to record that reservation occur outside
2601 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2602 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2604 goto backout_unlocked
;
2607 spin_lock(&mm
->page_table_lock
);
2608 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2613 if (!huge_pte_none(huge_ptep_get(ptep
)))
2617 hugepage_add_new_anon_rmap(page
, vma
, address
);
2619 page_dup_rmap(page
);
2620 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2621 && (vma
->vm_flags
& VM_SHARED
)));
2622 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2624 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2625 /* Optimization, do the COW without a second fault */
2626 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2629 spin_unlock(&mm
->page_table_lock
);
2635 spin_unlock(&mm
->page_table_lock
);
2642 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2643 unsigned long address
, unsigned int flags
)
2648 struct page
*page
= NULL
;
2649 struct page
*pagecache_page
= NULL
;
2650 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2651 struct hstate
*h
= hstate_vma(vma
);
2653 address
&= huge_page_mask(h
);
2655 ptep
= huge_pte_offset(mm
, address
);
2657 entry
= huge_ptep_get(ptep
);
2658 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2659 migration_entry_wait(mm
, (pmd_t
*)ptep
, address
);
2661 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2662 return VM_FAULT_HWPOISON_LARGE
|
2663 VM_FAULT_SET_HINDEX(h
- hstates
);
2666 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2668 return VM_FAULT_OOM
;
2671 * Serialize hugepage allocation and instantiation, so that we don't
2672 * get spurious allocation failures if two CPUs race to instantiate
2673 * the same page in the page cache.
2675 mutex_lock(&hugetlb_instantiation_mutex
);
2676 entry
= huge_ptep_get(ptep
);
2677 if (huge_pte_none(entry
)) {
2678 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2685 * If we are going to COW the mapping later, we examine the pending
2686 * reservations for this page now. This will ensure that any
2687 * allocations necessary to record that reservation occur outside the
2688 * spinlock. For private mappings, we also lookup the pagecache
2689 * page now as it is used to determine if a reservation has been
2692 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2693 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2698 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2699 pagecache_page
= hugetlbfs_pagecache_page(h
,
2704 * hugetlb_cow() requires page locks of pte_page(entry) and
2705 * pagecache_page, so here we need take the former one
2706 * when page != pagecache_page or !pagecache_page.
2707 * Note that locking order is always pagecache_page -> page,
2708 * so no worry about deadlock.
2710 page
= pte_page(entry
);
2711 if (page
!= pagecache_page
)
2714 spin_lock(&mm
->page_table_lock
);
2715 /* Check for a racing update before calling hugetlb_cow */
2716 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2717 goto out_page_table_lock
;
2720 if (flags
& FAULT_FLAG_WRITE
) {
2721 if (!pte_write(entry
)) {
2722 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2724 goto out_page_table_lock
;
2726 entry
= pte_mkdirty(entry
);
2728 entry
= pte_mkyoung(entry
);
2729 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2730 flags
& FAULT_FLAG_WRITE
))
2731 update_mmu_cache(vma
, address
, ptep
);
2733 out_page_table_lock
:
2734 spin_unlock(&mm
->page_table_lock
);
2736 if (pagecache_page
) {
2737 unlock_page(pagecache_page
);
2738 put_page(pagecache_page
);
2740 if (page
!= pagecache_page
)
2744 mutex_unlock(&hugetlb_instantiation_mutex
);
2749 /* Can be overriden by architectures */
2750 __attribute__((weak
)) struct page
*
2751 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2752 pud_t
*pud
, int write
)
2758 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2759 struct page
**pages
, struct vm_area_struct
**vmas
,
2760 unsigned long *position
, int *length
, int i
,
2763 unsigned long pfn_offset
;
2764 unsigned long vaddr
= *position
;
2765 int remainder
= *length
;
2766 struct hstate
*h
= hstate_vma(vma
);
2768 spin_lock(&mm
->page_table_lock
);
2769 while (vaddr
< vma
->vm_end
&& remainder
) {
2775 * Some archs (sparc64, sh*) have multiple pte_ts to
2776 * each hugepage. We have to make sure we get the
2777 * first, for the page indexing below to work.
2779 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2780 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2783 * When coredumping, it suits get_dump_page if we just return
2784 * an error where there's an empty slot with no huge pagecache
2785 * to back it. This way, we avoid allocating a hugepage, and
2786 * the sparse dumpfile avoids allocating disk blocks, but its
2787 * huge holes still show up with zeroes where they need to be.
2789 if (absent
&& (flags
& FOLL_DUMP
) &&
2790 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2796 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2799 spin_unlock(&mm
->page_table_lock
);
2800 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2801 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2802 spin_lock(&mm
->page_table_lock
);
2803 if (!(ret
& VM_FAULT_ERROR
))
2810 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2811 page
= pte_page(huge_ptep_get(pte
));
2814 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2825 if (vaddr
< vma
->vm_end
&& remainder
&&
2826 pfn_offset
< pages_per_huge_page(h
)) {
2828 * We use pfn_offset to avoid touching the pageframes
2829 * of this compound page.
2834 spin_unlock(&mm
->page_table_lock
);
2835 *length
= remainder
;
2838 return i
? i
: -EFAULT
;
2841 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2842 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2844 struct mm_struct
*mm
= vma
->vm_mm
;
2845 unsigned long start
= address
;
2848 struct hstate
*h
= hstate_vma(vma
);
2850 BUG_ON(address
>= end
);
2851 flush_cache_range(vma
, address
, end
);
2853 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2854 spin_lock(&mm
->page_table_lock
);
2855 for (; address
< end
; address
+= huge_page_size(h
)) {
2856 ptep
= huge_pte_offset(mm
, address
);
2859 if (huge_pmd_unshare(mm
, &address
, ptep
))
2861 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2862 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2863 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2864 set_huge_pte_at(mm
, address
, ptep
, pte
);
2867 spin_unlock(&mm
->page_table_lock
);
2868 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
2870 flush_tlb_range(vma
, start
, end
);
2873 int hugetlb_reserve_pages(struct inode
*inode
,
2875 struct vm_area_struct
*vma
,
2876 vm_flags_t vm_flags
)
2879 struct hstate
*h
= hstate_inode(inode
);
2882 * Only apply hugepage reservation if asked. At fault time, an
2883 * attempt will be made for VM_NORESERVE to allocate a page
2884 * and filesystem quota without using reserves
2886 if (vm_flags
& VM_NORESERVE
)
2890 * Shared mappings base their reservation on the number of pages that
2891 * are already allocated on behalf of the file. Private mappings need
2892 * to reserve the full area even if read-only as mprotect() may be
2893 * called to make the mapping read-write. Assume !vma is a shm mapping
2895 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2896 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2898 struct resv_map
*resv_map
= resv_map_alloc();
2904 set_vma_resv_map(vma
, resv_map
);
2905 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2911 /* There must be enough filesystem quota for the mapping */
2912 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2916 * Check enough hugepages are available for the reservation.
2917 * Hand back the quota if there are not
2919 ret
= hugetlb_acct_memory(h
, chg
);
2921 hugetlb_put_quota(inode
->i_mapping
, chg
);
2926 * Account for the reservations made. Shared mappings record regions
2927 * that have reservations as they are shared by multiple VMAs.
2928 * When the last VMA disappears, the region map says how much
2929 * the reservation was and the page cache tells how much of
2930 * the reservation was consumed. Private mappings are per-VMA and
2931 * only the consumed reservations are tracked. When the VMA
2932 * disappears, the original reservation is the VMA size and the
2933 * consumed reservations are stored in the map. Hence, nothing
2934 * else has to be done for private mappings here
2936 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2937 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2941 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2943 struct hstate
*h
= hstate_inode(inode
);
2944 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2946 spin_lock(&inode
->i_lock
);
2947 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
2948 spin_unlock(&inode
->i_lock
);
2950 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2951 hugetlb_acct_memory(h
, -(chg
- freed
));
2954 #ifdef CONFIG_MEMORY_FAILURE
2956 /* Should be called in hugetlb_lock */
2957 static int is_hugepage_on_freelist(struct page
*hpage
)
2961 struct hstate
*h
= page_hstate(hpage
);
2962 int nid
= page_to_nid(hpage
);
2964 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
2971 * This function is called from memory failure code.
2972 * Assume the caller holds page lock of the head page.
2974 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
2976 struct hstate
*h
= page_hstate(hpage
);
2977 int nid
= page_to_nid(hpage
);
2980 spin_lock(&hugetlb_lock
);
2981 if (is_hugepage_on_freelist(hpage
)) {
2982 list_del(&hpage
->lru
);
2983 set_page_refcounted(hpage
);
2984 h
->free_huge_pages
--;
2985 h
->free_huge_pages_node
[nid
]--;
2988 spin_unlock(&hugetlb_lock
);