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 futher 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 clear_gigantic_page(struct page
*page
,
398 unsigned long addr
, unsigned long sz
)
401 struct page
*p
= page
;
404 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++, p
= mem_map_next(p
, page
, i
)) {
406 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
409 static void clear_huge_page(struct page
*page
,
410 unsigned long addr
, unsigned long sz
)
414 if (unlikely(sz
/PAGE_SIZE
> MAX_ORDER_NR_PAGES
)) {
415 clear_gigantic_page(page
, addr
, sz
);
420 for (i
= 0; i
< sz
/PAGE_SIZE
; i
++) {
422 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
426 static void copy_user_gigantic_page(struct page
*dst
, struct page
*src
,
427 unsigned long addr
, struct vm_area_struct
*vma
)
430 struct hstate
*h
= hstate_vma(vma
);
431 struct page
*dst_base
= dst
;
432 struct page
*src_base
= src
;
434 for (i
= 0; i
< pages_per_huge_page(h
); ) {
436 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
439 dst
= mem_map_next(dst
, dst_base
, i
);
440 src
= mem_map_next(src
, src_base
, i
);
444 static void copy_user_huge_page(struct page
*dst
, struct page
*src
,
445 unsigned long addr
, struct vm_area_struct
*vma
)
448 struct hstate
*h
= hstate_vma(vma
);
450 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
451 copy_user_gigantic_page(dst
, src
, addr
, vma
);
456 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
458 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
462 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
465 struct hstate
*h
= page_hstate(src
);
466 struct page
*dst_base
= dst
;
467 struct page
*src_base
= src
;
469 for (i
= 0; i
< pages_per_huge_page(h
); ) {
471 copy_highpage(dst
, src
);
474 dst
= mem_map_next(dst
, dst_base
, i
);
475 src
= mem_map_next(src
, src_base
, i
);
479 void copy_huge_page(struct page
*dst
, struct page
*src
)
482 struct hstate
*h
= page_hstate(src
);
484 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
485 copy_gigantic_page(dst
, src
);
490 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
492 copy_highpage(dst
+ i
, src
+ i
);
496 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
498 int nid
= page_to_nid(page
);
499 list_add(&page
->lru
, &h
->hugepage_freelists
[nid
]);
500 h
->free_huge_pages
++;
501 h
->free_huge_pages_node
[nid
]++;
504 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
508 if (list_empty(&h
->hugepage_freelists
[nid
]))
510 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
511 list_del(&page
->lru
);
512 h
->free_huge_pages
--;
513 h
->free_huge_pages_node
[nid
]--;
517 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
518 struct vm_area_struct
*vma
,
519 unsigned long address
, int avoid_reserve
)
521 struct page
*page
= NULL
;
522 struct mempolicy
*mpol
;
523 nodemask_t
*nodemask
;
524 struct zonelist
*zonelist
;
529 zonelist
= huge_zonelist(vma
, address
,
530 htlb_alloc_mask
, &mpol
, &nodemask
);
532 * A child process with MAP_PRIVATE mappings created by their parent
533 * have no page reserves. This check ensures that reservations are
534 * not "stolen". The child may still get SIGKILLed
536 if (!vma_has_reserves(vma
) &&
537 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
540 /* If reserves cannot be used, ensure enough pages are in the pool */
541 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
544 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
545 MAX_NR_ZONES
- 1, nodemask
) {
546 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
547 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
550 decrement_hugepage_resv_vma(h
, vma
);
561 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
565 VM_BUG_ON(h
->order
>= MAX_ORDER
);
568 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
569 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
570 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
571 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
572 1 << PG_private
| 1<< PG_writeback
);
574 set_compound_page_dtor(page
, NULL
);
575 set_page_refcounted(page
);
576 arch_release_hugepage(page
);
577 __free_pages(page
, huge_page_order(h
));
580 struct hstate
*size_to_hstate(unsigned long size
)
585 if (huge_page_size(h
) == size
)
591 static void free_huge_page(struct page
*page
)
594 * Can't pass hstate in here because it is called from the
595 * compound page destructor.
597 struct hstate
*h
= page_hstate(page
);
598 int nid
= page_to_nid(page
);
599 struct address_space
*mapping
;
601 mapping
= (struct address_space
*) page_private(page
);
602 set_page_private(page
, 0);
603 page
->mapping
= NULL
;
604 BUG_ON(page_count(page
));
605 BUG_ON(page_mapcount(page
));
606 INIT_LIST_HEAD(&page
->lru
);
608 spin_lock(&hugetlb_lock
);
609 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
610 update_and_free_page(h
, page
);
611 h
->surplus_huge_pages
--;
612 h
->surplus_huge_pages_node
[nid
]--;
614 enqueue_huge_page(h
, page
);
616 spin_unlock(&hugetlb_lock
);
618 hugetlb_put_quota(mapping
, 1);
621 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
623 set_compound_page_dtor(page
, free_huge_page
);
624 spin_lock(&hugetlb_lock
);
626 h
->nr_huge_pages_node
[nid
]++;
627 spin_unlock(&hugetlb_lock
);
628 put_page(page
); /* free it into the hugepage allocator */
631 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
634 int nr_pages
= 1 << order
;
635 struct page
*p
= page
+ 1;
637 /* we rely on prep_new_huge_page to set the destructor */
638 set_compound_order(page
, order
);
640 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
642 p
->first_page
= page
;
646 int PageHuge(struct page
*page
)
648 compound_page_dtor
*dtor
;
650 if (!PageCompound(page
))
653 page
= compound_head(page
);
654 dtor
= get_compound_page_dtor(page
);
656 return dtor
== free_huge_page
;
659 EXPORT_SYMBOL_GPL(PageHuge
);
661 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
665 if (h
->order
>= MAX_ORDER
)
668 page
= alloc_pages_exact_node(nid
,
669 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
670 __GFP_REPEAT
|__GFP_NOWARN
,
673 if (arch_prepare_hugepage(page
)) {
674 __free_pages(page
, huge_page_order(h
));
677 prep_new_huge_page(h
, page
, nid
);
684 * common helper functions for hstate_next_node_to_{alloc|free}.
685 * We may have allocated or freed a huge page based on a different
686 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
687 * be outside of *nodes_allowed. Ensure that we use an allowed
688 * node for alloc or free.
690 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
692 nid
= next_node(nid
, *nodes_allowed
);
693 if (nid
== MAX_NUMNODES
)
694 nid
= first_node(*nodes_allowed
);
695 VM_BUG_ON(nid
>= MAX_NUMNODES
);
700 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
702 if (!node_isset(nid
, *nodes_allowed
))
703 nid
= next_node_allowed(nid
, nodes_allowed
);
708 * returns the previously saved node ["this node"] from which to
709 * allocate a persistent huge page for the pool and advance the
710 * next node from which to allocate, handling wrap at end of node
713 static int hstate_next_node_to_alloc(struct hstate
*h
,
714 nodemask_t
*nodes_allowed
)
718 VM_BUG_ON(!nodes_allowed
);
720 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
721 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
726 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
733 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
734 next_nid
= start_nid
;
737 page
= alloc_fresh_huge_page_node(h
, next_nid
);
742 next_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
743 } while (next_nid
!= start_nid
);
746 count_vm_event(HTLB_BUDDY_PGALLOC
);
748 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
754 * helper for free_pool_huge_page() - return the previously saved
755 * node ["this node"] from which to free a huge page. Advance the
756 * next node id whether or not we find a free huge page to free so
757 * that the next attempt to free addresses the next node.
759 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
763 VM_BUG_ON(!nodes_allowed
);
765 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
766 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
772 * Free huge page from pool from next node to free.
773 * Attempt to keep persistent huge pages more or less
774 * balanced over allowed nodes.
775 * Called with hugetlb_lock locked.
777 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
784 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
785 next_nid
= start_nid
;
789 * If we're returning unused surplus pages, only examine
790 * nodes with surplus pages.
792 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[next_nid
]) &&
793 !list_empty(&h
->hugepage_freelists
[next_nid
])) {
795 list_entry(h
->hugepage_freelists
[next_nid
].next
,
797 list_del(&page
->lru
);
798 h
->free_huge_pages
--;
799 h
->free_huge_pages_node
[next_nid
]--;
801 h
->surplus_huge_pages
--;
802 h
->surplus_huge_pages_node
[next_nid
]--;
804 update_and_free_page(h
, page
);
808 next_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
809 } while (next_nid
!= start_nid
);
814 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
819 if (h
->order
>= MAX_ORDER
)
823 * Assume we will successfully allocate the surplus page to
824 * prevent racing processes from causing the surplus to exceed
827 * This however introduces a different race, where a process B
828 * tries to grow the static hugepage pool while alloc_pages() is
829 * called by process A. B will only examine the per-node
830 * counters in determining if surplus huge pages can be
831 * converted to normal huge pages in adjust_pool_surplus(). A
832 * won't be able to increment the per-node counter, until the
833 * lock is dropped by B, but B doesn't drop hugetlb_lock until
834 * no more huge pages can be converted from surplus to normal
835 * state (and doesn't try to convert again). Thus, we have a
836 * case where a surplus huge page exists, the pool is grown, and
837 * the surplus huge page still exists after, even though it
838 * should just have been converted to a normal huge page. This
839 * does not leak memory, though, as the hugepage will be freed
840 * once it is out of use. It also does not allow the counters to
841 * go out of whack in adjust_pool_surplus() as we don't modify
842 * the node values until we've gotten the hugepage and only the
843 * per-node value is checked there.
845 spin_lock(&hugetlb_lock
);
846 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
847 spin_unlock(&hugetlb_lock
);
851 h
->surplus_huge_pages
++;
853 spin_unlock(&hugetlb_lock
);
855 if (nid
== NUMA_NO_NODE
)
856 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
857 __GFP_REPEAT
|__GFP_NOWARN
,
860 page
= alloc_pages_exact_node(nid
,
861 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
862 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
864 if (page
&& arch_prepare_hugepage(page
)) {
865 __free_pages(page
, huge_page_order(h
));
869 spin_lock(&hugetlb_lock
);
872 * This page is now managed by the hugetlb allocator and has
873 * no users -- drop the buddy allocator's reference.
875 put_page_testzero(page
);
876 VM_BUG_ON(page_count(page
));
877 r_nid
= page_to_nid(page
);
878 set_compound_page_dtor(page
, free_huge_page
);
880 * We incremented the global counters already
882 h
->nr_huge_pages_node
[r_nid
]++;
883 h
->surplus_huge_pages_node
[r_nid
]++;
884 __count_vm_event(HTLB_BUDDY_PGALLOC
);
887 h
->surplus_huge_pages
--;
888 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
890 spin_unlock(&hugetlb_lock
);
896 * This allocation function is useful in the context where vma is irrelevant.
897 * E.g. soft-offlining uses this function because it only cares physical
898 * address of error page.
900 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
904 spin_lock(&hugetlb_lock
);
905 page
= dequeue_huge_page_node(h
, nid
);
906 spin_unlock(&hugetlb_lock
);
909 page
= alloc_buddy_huge_page(h
, nid
);
915 * Increase the hugetlb pool such that it can accomodate a reservation
918 static int gather_surplus_pages(struct hstate
*h
, int delta
)
920 struct list_head surplus_list
;
921 struct page
*page
, *tmp
;
923 int needed
, allocated
;
925 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
927 h
->resv_huge_pages
+= delta
;
932 INIT_LIST_HEAD(&surplus_list
);
936 spin_unlock(&hugetlb_lock
);
937 for (i
= 0; i
< needed
; i
++) {
938 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
941 * We were not able to allocate enough pages to
942 * satisfy the entire reservation so we free what
943 * we've allocated so far.
945 spin_lock(&hugetlb_lock
);
950 list_add(&page
->lru
, &surplus_list
);
955 * After retaking hugetlb_lock, we need to recalculate 'needed'
956 * because either resv_huge_pages or free_huge_pages may have changed.
958 spin_lock(&hugetlb_lock
);
959 needed
= (h
->resv_huge_pages
+ delta
) -
960 (h
->free_huge_pages
+ allocated
);
965 * The surplus_list now contains _at_least_ the number of extra pages
966 * needed to accomodate the reservation. Add the appropriate number
967 * of pages to the hugetlb pool and free the extras back to the buddy
968 * allocator. Commit the entire reservation here to prevent another
969 * process from stealing the pages as they are added to the pool but
970 * before they are reserved.
973 h
->resv_huge_pages
+= delta
;
976 /* Free the needed pages to the hugetlb pool */
977 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
980 list_del(&page
->lru
);
981 enqueue_huge_page(h
, page
);
984 /* Free unnecessary surplus pages to the buddy allocator */
985 if (!list_empty(&surplus_list
)) {
986 spin_unlock(&hugetlb_lock
);
987 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
988 list_del(&page
->lru
);
990 * The page has a reference count of zero already, so
991 * call free_huge_page directly instead of using
992 * put_page. This must be done with hugetlb_lock
993 * unlocked which is safe because free_huge_page takes
994 * hugetlb_lock before deciding how to free the page.
996 free_huge_page(page
);
998 spin_lock(&hugetlb_lock
);
1005 * When releasing a hugetlb pool reservation, any surplus pages that were
1006 * allocated to satisfy the reservation must be explicitly freed if they were
1008 * Called with hugetlb_lock held.
1010 static void return_unused_surplus_pages(struct hstate
*h
,
1011 unsigned long unused_resv_pages
)
1013 unsigned long nr_pages
;
1015 /* Uncommit the reservation */
1016 h
->resv_huge_pages
-= unused_resv_pages
;
1018 /* Cannot return gigantic pages currently */
1019 if (h
->order
>= MAX_ORDER
)
1022 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1025 * We want to release as many surplus pages as possible, spread
1026 * evenly across all nodes with memory. Iterate across these nodes
1027 * until we can no longer free unreserved surplus pages. This occurs
1028 * when the nodes with surplus pages have no free pages.
1029 * free_pool_huge_page() will balance the the freed pages across the
1030 * on-line nodes with memory and will handle the hstate accounting.
1032 while (nr_pages
--) {
1033 if (!free_pool_huge_page(h
, &node_states
[N_HIGH_MEMORY
], 1))
1039 * Determine if the huge page at addr within the vma has an associated
1040 * reservation. Where it does not we will need to logically increase
1041 * reservation and actually increase quota before an allocation can occur.
1042 * Where any new reservation would be required the reservation change is
1043 * prepared, but not committed. Once the page has been quota'd allocated
1044 * an instantiated the change should be committed via vma_commit_reservation.
1045 * No action is required on failure.
1047 static long vma_needs_reservation(struct hstate
*h
,
1048 struct vm_area_struct
*vma
, unsigned long addr
)
1050 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1051 struct inode
*inode
= mapping
->host
;
1053 if (vma
->vm_flags
& VM_MAYSHARE
) {
1054 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1055 return region_chg(&inode
->i_mapping
->private_list
,
1058 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1063 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1064 struct resv_map
*reservations
= vma_resv_map(vma
);
1066 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1072 static void vma_commit_reservation(struct hstate
*h
,
1073 struct vm_area_struct
*vma
, unsigned long addr
)
1075 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1076 struct inode
*inode
= mapping
->host
;
1078 if (vma
->vm_flags
& VM_MAYSHARE
) {
1079 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1080 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1082 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1083 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1084 struct resv_map
*reservations
= vma_resv_map(vma
);
1086 /* Mark this page used in the map. */
1087 region_add(&reservations
->regions
, idx
, idx
+ 1);
1091 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1092 unsigned long addr
, int avoid_reserve
)
1094 struct hstate
*h
= hstate_vma(vma
);
1096 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1097 struct inode
*inode
= mapping
->host
;
1101 * Processes that did not create the mapping will have no reserves and
1102 * will not have accounted against quota. Check that the quota can be
1103 * made before satisfying the allocation
1104 * MAP_NORESERVE mappings may also need pages and quota allocated
1105 * if no reserve mapping overlaps.
1107 chg
= vma_needs_reservation(h
, vma
, addr
);
1109 return ERR_PTR(chg
);
1111 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
1112 return ERR_PTR(-ENOSPC
);
1114 spin_lock(&hugetlb_lock
);
1115 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1116 spin_unlock(&hugetlb_lock
);
1119 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1121 hugetlb_put_quota(inode
->i_mapping
, chg
);
1122 return ERR_PTR(-VM_FAULT_SIGBUS
);
1126 set_page_refcounted(page
);
1127 set_page_private(page
, (unsigned long) mapping
);
1129 vma_commit_reservation(h
, vma
, addr
);
1134 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1136 struct huge_bootmem_page
*m
;
1137 int nr_nodes
= nodes_weight(node_states
[N_HIGH_MEMORY
]);
1142 addr
= __alloc_bootmem_node_nopanic(
1143 NODE_DATA(hstate_next_node_to_alloc(h
,
1144 &node_states
[N_HIGH_MEMORY
])),
1145 huge_page_size(h
), huge_page_size(h
), 0);
1149 * Use the beginning of the huge page to store the
1150 * huge_bootmem_page struct (until gather_bootmem
1151 * puts them into the mem_map).
1161 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1162 /* Put them into a private list first because mem_map is not up yet */
1163 list_add(&m
->list
, &huge_boot_pages
);
1168 static void prep_compound_huge_page(struct page
*page
, int order
)
1170 if (unlikely(order
> (MAX_ORDER
- 1)))
1171 prep_compound_gigantic_page(page
, order
);
1173 prep_compound_page(page
, order
);
1176 /* Put bootmem huge pages into the standard lists after mem_map is up */
1177 static void __init
gather_bootmem_prealloc(void)
1179 struct huge_bootmem_page
*m
;
1181 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1182 struct page
*page
= virt_to_page(m
);
1183 struct hstate
*h
= m
->hstate
;
1184 __ClearPageReserved(page
);
1185 WARN_ON(page_count(page
) != 1);
1186 prep_compound_huge_page(page
, h
->order
);
1187 prep_new_huge_page(h
, page
, page_to_nid(page
));
1191 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1195 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1196 if (h
->order
>= MAX_ORDER
) {
1197 if (!alloc_bootmem_huge_page(h
))
1199 } else if (!alloc_fresh_huge_page(h
,
1200 &node_states
[N_HIGH_MEMORY
]))
1203 h
->max_huge_pages
= i
;
1206 static void __init
hugetlb_init_hstates(void)
1210 for_each_hstate(h
) {
1211 /* oversize hugepages were init'ed in early boot */
1212 if (h
->order
< MAX_ORDER
)
1213 hugetlb_hstate_alloc_pages(h
);
1217 static char * __init
memfmt(char *buf
, unsigned long n
)
1219 if (n
>= (1UL << 30))
1220 sprintf(buf
, "%lu GB", n
>> 30);
1221 else if (n
>= (1UL << 20))
1222 sprintf(buf
, "%lu MB", n
>> 20);
1224 sprintf(buf
, "%lu KB", n
>> 10);
1228 static void __init
report_hugepages(void)
1232 for_each_hstate(h
) {
1234 printk(KERN_INFO
"HugeTLB registered %s page size, "
1235 "pre-allocated %ld pages\n",
1236 memfmt(buf
, huge_page_size(h
)),
1237 h
->free_huge_pages
);
1241 #ifdef CONFIG_HIGHMEM
1242 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1243 nodemask_t
*nodes_allowed
)
1247 if (h
->order
>= MAX_ORDER
)
1250 for_each_node_mask(i
, *nodes_allowed
) {
1251 struct page
*page
, *next
;
1252 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1253 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1254 if (count
>= h
->nr_huge_pages
)
1256 if (PageHighMem(page
))
1258 list_del(&page
->lru
);
1259 update_and_free_page(h
, page
);
1260 h
->free_huge_pages
--;
1261 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1266 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1267 nodemask_t
*nodes_allowed
)
1273 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1274 * balanced by operating on them in a round-robin fashion.
1275 * Returns 1 if an adjustment was made.
1277 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1280 int start_nid
, next_nid
;
1283 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1286 start_nid
= hstate_next_node_to_alloc(h
, nodes_allowed
);
1288 start_nid
= hstate_next_node_to_free(h
, nodes_allowed
);
1289 next_nid
= start_nid
;
1295 * To shrink on this node, there must be a surplus page
1297 if (!h
->surplus_huge_pages_node
[nid
]) {
1298 next_nid
= hstate_next_node_to_alloc(h
,
1305 * Surplus cannot exceed the total number of pages
1307 if (h
->surplus_huge_pages_node
[nid
] >=
1308 h
->nr_huge_pages_node
[nid
]) {
1309 next_nid
= hstate_next_node_to_free(h
,
1315 h
->surplus_huge_pages
+= delta
;
1316 h
->surplus_huge_pages_node
[nid
] += delta
;
1319 } while (next_nid
!= start_nid
);
1324 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1325 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1326 nodemask_t
*nodes_allowed
)
1328 unsigned long min_count
, ret
;
1330 if (h
->order
>= MAX_ORDER
)
1331 return h
->max_huge_pages
;
1334 * Increase the pool size
1335 * First take pages out of surplus state. Then make up the
1336 * remaining difference by allocating fresh huge pages.
1338 * We might race with alloc_buddy_huge_page() here and be unable
1339 * to convert a surplus huge page to a normal huge page. That is
1340 * not critical, though, it just means the overall size of the
1341 * pool might be one hugepage larger than it needs to be, but
1342 * within all the constraints specified by the sysctls.
1344 spin_lock(&hugetlb_lock
);
1345 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1346 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1350 while (count
> persistent_huge_pages(h
)) {
1352 * If this allocation races such that we no longer need the
1353 * page, free_huge_page will handle it by freeing the page
1354 * and reducing the surplus.
1356 spin_unlock(&hugetlb_lock
);
1357 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1358 spin_lock(&hugetlb_lock
);
1362 /* Bail for signals. Probably ctrl-c from user */
1363 if (signal_pending(current
))
1368 * Decrease the pool size
1369 * First return free pages to the buddy allocator (being careful
1370 * to keep enough around to satisfy reservations). Then place
1371 * pages into surplus state as needed so the pool will shrink
1372 * to the desired size as pages become free.
1374 * By placing pages into the surplus state independent of the
1375 * overcommit value, we are allowing the surplus pool size to
1376 * exceed overcommit. There are few sane options here. Since
1377 * alloc_buddy_huge_page() is checking the global counter,
1378 * though, we'll note that we're not allowed to exceed surplus
1379 * and won't grow the pool anywhere else. Not until one of the
1380 * sysctls are changed, or the surplus pages go out of use.
1382 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1383 min_count
= max(count
, min_count
);
1384 try_to_free_low(h
, min_count
, nodes_allowed
);
1385 while (min_count
< persistent_huge_pages(h
)) {
1386 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1389 while (count
< persistent_huge_pages(h
)) {
1390 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1394 ret
= persistent_huge_pages(h
);
1395 spin_unlock(&hugetlb_lock
);
1399 #define HSTATE_ATTR_RO(_name) \
1400 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1402 #define HSTATE_ATTR(_name) \
1403 static struct kobj_attribute _name##_attr = \
1404 __ATTR(_name, 0644, _name##_show, _name##_store)
1406 static struct kobject
*hugepages_kobj
;
1407 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1409 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1411 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1415 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1416 if (hstate_kobjs
[i
] == kobj
) {
1418 *nidp
= NUMA_NO_NODE
;
1422 return kobj_to_node_hstate(kobj
, nidp
);
1425 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1426 struct kobj_attribute
*attr
, char *buf
)
1429 unsigned long nr_huge_pages
;
1432 h
= kobj_to_hstate(kobj
, &nid
);
1433 if (nid
== NUMA_NO_NODE
)
1434 nr_huge_pages
= h
->nr_huge_pages
;
1436 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1438 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1440 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1441 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1442 const char *buf
, size_t len
)
1446 unsigned long count
;
1448 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1450 err
= strict_strtoul(buf
, 10, &count
);
1454 h
= kobj_to_hstate(kobj
, &nid
);
1455 if (nid
== NUMA_NO_NODE
) {
1457 * global hstate attribute
1459 if (!(obey_mempolicy
&&
1460 init_nodemask_of_mempolicy(nodes_allowed
))) {
1461 NODEMASK_FREE(nodes_allowed
);
1462 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1464 } else if (nodes_allowed
) {
1466 * per node hstate attribute: adjust count to global,
1467 * but restrict alloc/free to the specified node.
1469 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1470 init_nodemask_of_node(nodes_allowed
, nid
);
1472 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1474 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1476 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1477 NODEMASK_FREE(nodes_allowed
);
1482 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1483 struct kobj_attribute
*attr
, char *buf
)
1485 return nr_hugepages_show_common(kobj
, attr
, buf
);
1488 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1489 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1491 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1493 HSTATE_ATTR(nr_hugepages
);
1498 * hstate attribute for optionally mempolicy-based constraint on persistent
1499 * huge page alloc/free.
1501 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1502 struct kobj_attribute
*attr
, char *buf
)
1504 return nr_hugepages_show_common(kobj
, attr
, buf
);
1507 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1508 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1510 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1512 HSTATE_ATTR(nr_hugepages_mempolicy
);
1516 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1517 struct kobj_attribute
*attr
, char *buf
)
1519 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1520 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1522 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1523 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1526 unsigned long input
;
1527 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1529 err
= strict_strtoul(buf
, 10, &input
);
1533 spin_lock(&hugetlb_lock
);
1534 h
->nr_overcommit_huge_pages
= input
;
1535 spin_unlock(&hugetlb_lock
);
1539 HSTATE_ATTR(nr_overcommit_hugepages
);
1541 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1542 struct kobj_attribute
*attr
, char *buf
)
1545 unsigned long free_huge_pages
;
1548 h
= kobj_to_hstate(kobj
, &nid
);
1549 if (nid
== NUMA_NO_NODE
)
1550 free_huge_pages
= h
->free_huge_pages
;
1552 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1554 return sprintf(buf
, "%lu\n", free_huge_pages
);
1556 HSTATE_ATTR_RO(free_hugepages
);
1558 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1559 struct kobj_attribute
*attr
, char *buf
)
1561 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1562 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1564 HSTATE_ATTR_RO(resv_hugepages
);
1566 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1567 struct kobj_attribute
*attr
, char *buf
)
1570 unsigned long surplus_huge_pages
;
1573 h
= kobj_to_hstate(kobj
, &nid
);
1574 if (nid
== NUMA_NO_NODE
)
1575 surplus_huge_pages
= h
->surplus_huge_pages
;
1577 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1579 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1581 HSTATE_ATTR_RO(surplus_hugepages
);
1583 static struct attribute
*hstate_attrs
[] = {
1584 &nr_hugepages_attr
.attr
,
1585 &nr_overcommit_hugepages_attr
.attr
,
1586 &free_hugepages_attr
.attr
,
1587 &resv_hugepages_attr
.attr
,
1588 &surplus_hugepages_attr
.attr
,
1590 &nr_hugepages_mempolicy_attr
.attr
,
1595 static struct attribute_group hstate_attr_group
= {
1596 .attrs
= hstate_attrs
,
1599 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1600 struct kobject
**hstate_kobjs
,
1601 struct attribute_group
*hstate_attr_group
)
1604 int hi
= h
- hstates
;
1606 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1607 if (!hstate_kobjs
[hi
])
1610 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1612 kobject_put(hstate_kobjs
[hi
]);
1617 static void __init
hugetlb_sysfs_init(void)
1622 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1623 if (!hugepages_kobj
)
1626 for_each_hstate(h
) {
1627 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1628 hstate_kobjs
, &hstate_attr_group
);
1630 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s",
1638 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1639 * with node sysdevs in node_devices[] using a parallel array. The array
1640 * index of a node sysdev or _hstate == node id.
1641 * This is here to avoid any static dependency of the node sysdev driver, in
1642 * the base kernel, on the hugetlb module.
1644 struct node_hstate
{
1645 struct kobject
*hugepages_kobj
;
1646 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1648 struct node_hstate node_hstates
[MAX_NUMNODES
];
1651 * A subset of global hstate attributes for node sysdevs
1653 static struct attribute
*per_node_hstate_attrs
[] = {
1654 &nr_hugepages_attr
.attr
,
1655 &free_hugepages_attr
.attr
,
1656 &surplus_hugepages_attr
.attr
,
1660 static struct attribute_group per_node_hstate_attr_group
= {
1661 .attrs
= per_node_hstate_attrs
,
1665 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
1666 * Returns node id via non-NULL nidp.
1668 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1672 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1673 struct node_hstate
*nhs
= &node_hstates
[nid
];
1675 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1676 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1688 * Unregister hstate attributes from a single node sysdev.
1689 * No-op if no hstate attributes attached.
1691 void hugetlb_unregister_node(struct node
*node
)
1694 struct node_hstate
*nhs
= &node_hstates
[node
->sysdev
.id
];
1696 if (!nhs
->hugepages_kobj
)
1697 return; /* no hstate attributes */
1700 if (nhs
->hstate_kobjs
[h
- hstates
]) {
1701 kobject_put(nhs
->hstate_kobjs
[h
- hstates
]);
1702 nhs
->hstate_kobjs
[h
- hstates
] = NULL
;
1705 kobject_put(nhs
->hugepages_kobj
);
1706 nhs
->hugepages_kobj
= NULL
;
1710 * hugetlb module exit: unregister hstate attributes from node sysdevs
1713 static void hugetlb_unregister_all_nodes(void)
1718 * disable node sysdev registrations.
1720 register_hugetlbfs_with_node(NULL
, NULL
);
1723 * remove hstate attributes from any nodes that have them.
1725 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1726 hugetlb_unregister_node(&node_devices
[nid
]);
1730 * Register hstate attributes for a single node sysdev.
1731 * No-op if attributes already registered.
1733 void hugetlb_register_node(struct node
*node
)
1736 struct node_hstate
*nhs
= &node_hstates
[node
->sysdev
.id
];
1739 if (nhs
->hugepages_kobj
)
1740 return; /* already allocated */
1742 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1743 &node
->sysdev
.kobj
);
1744 if (!nhs
->hugepages_kobj
)
1747 for_each_hstate(h
) {
1748 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1750 &per_node_hstate_attr_group
);
1752 printk(KERN_ERR
"Hugetlb: Unable to add hstate %s"
1754 h
->name
, node
->sysdev
.id
);
1755 hugetlb_unregister_node(node
);
1762 * hugetlb init time: register hstate attributes for all registered node
1763 * sysdevs of nodes that have memory. All on-line nodes should have
1764 * registered their associated sysdev by this time.
1766 static void hugetlb_register_all_nodes(void)
1770 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1771 struct node
*node
= &node_devices
[nid
];
1772 if (node
->sysdev
.id
== nid
)
1773 hugetlb_register_node(node
);
1777 * Let the node sysdev driver know we're here so it can
1778 * [un]register hstate attributes on node hotplug.
1780 register_hugetlbfs_with_node(hugetlb_register_node
,
1781 hugetlb_unregister_node
);
1783 #else /* !CONFIG_NUMA */
1785 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1793 static void hugetlb_unregister_all_nodes(void) { }
1795 static void hugetlb_register_all_nodes(void) { }
1799 static void __exit
hugetlb_exit(void)
1803 hugetlb_unregister_all_nodes();
1805 for_each_hstate(h
) {
1806 kobject_put(hstate_kobjs
[h
- hstates
]);
1809 kobject_put(hugepages_kobj
);
1811 module_exit(hugetlb_exit
);
1813 static int __init
hugetlb_init(void)
1815 /* Some platform decide whether they support huge pages at boot
1816 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1817 * there is no such support
1819 if (HPAGE_SHIFT
== 0)
1822 if (!size_to_hstate(default_hstate_size
)) {
1823 default_hstate_size
= HPAGE_SIZE
;
1824 if (!size_to_hstate(default_hstate_size
))
1825 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1827 default_hstate_idx
= size_to_hstate(default_hstate_size
) - hstates
;
1828 if (default_hstate_max_huge_pages
)
1829 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1831 hugetlb_init_hstates();
1833 gather_bootmem_prealloc();
1837 hugetlb_sysfs_init();
1839 hugetlb_register_all_nodes();
1843 module_init(hugetlb_init
);
1845 /* Should be called on processing a hugepagesz=... option */
1846 void __init
hugetlb_add_hstate(unsigned order
)
1851 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1852 printk(KERN_WARNING
"hugepagesz= specified twice, ignoring\n");
1855 BUG_ON(max_hstate
>= HUGE_MAX_HSTATE
);
1857 h
= &hstates
[max_hstate
++];
1859 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1860 h
->nr_huge_pages
= 0;
1861 h
->free_huge_pages
= 0;
1862 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1863 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1864 h
->next_nid_to_alloc
= first_node(node_states
[N_HIGH_MEMORY
]);
1865 h
->next_nid_to_free
= first_node(node_states
[N_HIGH_MEMORY
]);
1866 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1867 huge_page_size(h
)/1024);
1872 static int __init
hugetlb_nrpages_setup(char *s
)
1875 static unsigned long *last_mhp
;
1878 * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1879 * so this hugepages= parameter goes to the "default hstate".
1882 mhp
= &default_hstate_max_huge_pages
;
1884 mhp
= &parsed_hstate
->max_huge_pages
;
1886 if (mhp
== last_mhp
) {
1887 printk(KERN_WARNING
"hugepages= specified twice without "
1888 "interleaving hugepagesz=, ignoring\n");
1892 if (sscanf(s
, "%lu", mhp
) <= 0)
1896 * Global state is always initialized later in hugetlb_init.
1897 * But we need to allocate >= MAX_ORDER hstates here early to still
1898 * use the bootmem allocator.
1900 if (max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1901 hugetlb_hstate_alloc_pages(parsed_hstate
);
1907 __setup("hugepages=", hugetlb_nrpages_setup
);
1909 static int __init
hugetlb_default_setup(char *s
)
1911 default_hstate_size
= memparse(s
, &s
);
1914 __setup("default_hugepagesz=", hugetlb_default_setup
);
1916 static unsigned int cpuset_mems_nr(unsigned int *array
)
1919 unsigned int nr
= 0;
1921 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1927 #ifdef CONFIG_SYSCTL
1928 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1929 struct ctl_table
*table
, int write
,
1930 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1932 struct hstate
*h
= &default_hstate
;
1936 tmp
= h
->max_huge_pages
;
1939 table
->maxlen
= sizeof(unsigned long);
1940 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
1943 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
1944 GFP_KERNEL
| __GFP_NORETRY
);
1945 if (!(obey_mempolicy
&&
1946 init_nodemask_of_mempolicy(nodes_allowed
))) {
1947 NODEMASK_FREE(nodes_allowed
);
1948 nodes_allowed
= &node_states
[N_HIGH_MEMORY
];
1950 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
1952 if (nodes_allowed
!= &node_states
[N_HIGH_MEMORY
])
1953 NODEMASK_FREE(nodes_allowed
);
1959 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
1960 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1963 return hugetlb_sysctl_handler_common(false, table
, write
,
1964 buffer
, length
, ppos
);
1968 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
1969 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1971 return hugetlb_sysctl_handler_common(true, table
, write
,
1972 buffer
, length
, ppos
);
1974 #endif /* CONFIG_NUMA */
1976 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
1977 void __user
*buffer
,
1978 size_t *length
, loff_t
*ppos
)
1980 proc_dointvec(table
, write
, buffer
, length
, ppos
);
1981 if (hugepages_treat_as_movable
)
1982 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
1984 htlb_alloc_mask
= GFP_HIGHUSER
;
1988 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
1989 void __user
*buffer
,
1990 size_t *length
, loff_t
*ppos
)
1992 struct hstate
*h
= &default_hstate
;
1996 tmp
= h
->nr_overcommit_huge_pages
;
1999 table
->maxlen
= sizeof(unsigned long);
2000 proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2003 spin_lock(&hugetlb_lock
);
2004 h
->nr_overcommit_huge_pages
= tmp
;
2005 spin_unlock(&hugetlb_lock
);
2011 #endif /* CONFIG_SYSCTL */
2013 void hugetlb_report_meminfo(struct seq_file
*m
)
2015 struct hstate
*h
= &default_hstate
;
2017 "HugePages_Total: %5lu\n"
2018 "HugePages_Free: %5lu\n"
2019 "HugePages_Rsvd: %5lu\n"
2020 "HugePages_Surp: %5lu\n"
2021 "Hugepagesize: %8lu kB\n",
2025 h
->surplus_huge_pages
,
2026 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2029 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2031 struct hstate
*h
= &default_hstate
;
2033 "Node %d HugePages_Total: %5u\n"
2034 "Node %d HugePages_Free: %5u\n"
2035 "Node %d HugePages_Surp: %5u\n",
2036 nid
, h
->nr_huge_pages_node
[nid
],
2037 nid
, h
->free_huge_pages_node
[nid
],
2038 nid
, h
->surplus_huge_pages_node
[nid
]);
2041 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2042 unsigned long hugetlb_total_pages(void)
2044 struct hstate
*h
= &default_hstate
;
2045 return h
->nr_huge_pages
* pages_per_huge_page(h
);
2048 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2052 spin_lock(&hugetlb_lock
);
2054 * When cpuset is configured, it breaks the strict hugetlb page
2055 * reservation as the accounting is done on a global variable. Such
2056 * reservation is completely rubbish in the presence of cpuset because
2057 * the reservation is not checked against page availability for the
2058 * current cpuset. Application can still potentially OOM'ed by kernel
2059 * with lack of free htlb page in cpuset that the task is in.
2060 * Attempt to enforce strict accounting with cpuset is almost
2061 * impossible (or too ugly) because cpuset is too fluid that
2062 * task or memory node can be dynamically moved between cpusets.
2064 * The change of semantics for shared hugetlb mapping with cpuset is
2065 * undesirable. However, in order to preserve some of the semantics,
2066 * we fall back to check against current free page availability as
2067 * a best attempt and hopefully to minimize the impact of changing
2068 * semantics that cpuset has.
2071 if (gather_surplus_pages(h
, delta
) < 0)
2074 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2075 return_unused_surplus_pages(h
, delta
);
2082 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2085 spin_unlock(&hugetlb_lock
);
2089 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2091 struct resv_map
*reservations
= vma_resv_map(vma
);
2094 * This new VMA should share its siblings reservation map if present.
2095 * The VMA will only ever have a valid reservation map pointer where
2096 * it is being copied for another still existing VMA. As that VMA
2097 * has a reference to the reservation map it cannot dissappear until
2098 * after this open call completes. It is therefore safe to take a
2099 * new reference here without additional locking.
2102 kref_get(&reservations
->refs
);
2105 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2107 struct hstate
*h
= hstate_vma(vma
);
2108 struct resv_map
*reservations
= vma_resv_map(vma
);
2109 unsigned long reserve
;
2110 unsigned long start
;
2114 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2115 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2117 reserve
= (end
- start
) -
2118 region_count(&reservations
->regions
, start
, end
);
2120 kref_put(&reservations
->refs
, resv_map_release
);
2123 hugetlb_acct_memory(h
, -reserve
);
2124 hugetlb_put_quota(vma
->vm_file
->f_mapping
, reserve
);
2130 * We cannot handle pagefaults against hugetlb pages at all. They cause
2131 * handle_mm_fault() to try to instantiate regular-sized pages in the
2132 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2135 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2141 const struct vm_operations_struct hugetlb_vm_ops
= {
2142 .fault
= hugetlb_vm_op_fault
,
2143 .open
= hugetlb_vm_op_open
,
2144 .close
= hugetlb_vm_op_close
,
2147 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2154 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
2156 entry
= huge_pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
2158 entry
= pte_mkyoung(entry
);
2159 entry
= pte_mkhuge(entry
);
2164 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2165 unsigned long address
, pte_t
*ptep
)
2169 entry
= pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep
)));
2170 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
2171 update_mmu_cache(vma
, address
, ptep
);
2176 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2177 struct vm_area_struct
*vma
)
2179 pte_t
*src_pte
, *dst_pte
, entry
;
2180 struct page
*ptepage
;
2183 struct hstate
*h
= hstate_vma(vma
);
2184 unsigned long sz
= huge_page_size(h
);
2186 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2188 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2189 src_pte
= huge_pte_offset(src
, addr
);
2192 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2196 /* If the pagetables are shared don't copy or take references */
2197 if (dst_pte
== src_pte
)
2200 spin_lock(&dst
->page_table_lock
);
2201 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2202 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2204 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2205 entry
= huge_ptep_get(src_pte
);
2206 ptepage
= pte_page(entry
);
2208 page_dup_rmap(ptepage
);
2209 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2211 spin_unlock(&src
->page_table_lock
);
2212 spin_unlock(&dst
->page_table_lock
);
2220 static int is_hugetlb_entry_migration(pte_t pte
)
2224 if (huge_pte_none(pte
) || pte_present(pte
))
2226 swp
= pte_to_swp_entry(pte
);
2227 if (non_swap_entry(swp
) && is_migration_entry(swp
)) {
2233 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2237 if (huge_pte_none(pte
) || pte_present(pte
))
2239 swp
= pte_to_swp_entry(pte
);
2240 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
)) {
2246 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2247 unsigned long end
, struct page
*ref_page
)
2249 struct mm_struct
*mm
= vma
->vm_mm
;
2250 unsigned long address
;
2255 struct hstate
*h
= hstate_vma(vma
);
2256 unsigned long sz
= huge_page_size(h
);
2259 * A page gathering list, protected by per file i_mmap_lock. The
2260 * lock is used to avoid list corruption from multiple unmapping
2261 * of the same page since we are using page->lru.
2263 LIST_HEAD(page_list
);
2265 WARN_ON(!is_vm_hugetlb_page(vma
));
2266 BUG_ON(start
& ~huge_page_mask(h
));
2267 BUG_ON(end
& ~huge_page_mask(h
));
2269 mmu_notifier_invalidate_range_start(mm
, start
, end
);
2270 spin_lock(&mm
->page_table_lock
);
2271 for (address
= start
; address
< end
; address
+= sz
) {
2272 ptep
= huge_pte_offset(mm
, address
);
2276 if (huge_pmd_unshare(mm
, &address
, ptep
))
2280 * If a reference page is supplied, it is because a specific
2281 * page is being unmapped, not a range. Ensure the page we
2282 * are about to unmap is the actual page of interest.
2285 pte
= huge_ptep_get(ptep
);
2286 if (huge_pte_none(pte
))
2288 page
= pte_page(pte
);
2289 if (page
!= ref_page
)
2293 * Mark the VMA as having unmapped its page so that
2294 * future faults in this VMA will fail rather than
2295 * looking like data was lost
2297 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2300 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2301 if (huge_pte_none(pte
))
2305 * HWPoisoned hugepage is already unmapped and dropped reference
2307 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
)))
2310 page
= pte_page(pte
);
2312 set_page_dirty(page
);
2313 list_add(&page
->lru
, &page_list
);
2315 spin_unlock(&mm
->page_table_lock
);
2316 flush_tlb_range(vma
, start
, end
);
2317 mmu_notifier_invalidate_range_end(mm
, start
, end
);
2318 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
2319 page_remove_rmap(page
);
2320 list_del(&page
->lru
);
2325 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2326 unsigned long end
, struct page
*ref_page
)
2328 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2329 __unmap_hugepage_range(vma
, start
, end
, ref_page
);
2330 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2334 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2335 * mappping it owns the reserve page for. The intention is to unmap the page
2336 * from other VMAs and let the children be SIGKILLed if they are faulting the
2339 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2340 struct page
*page
, unsigned long address
)
2342 struct hstate
*h
= hstate_vma(vma
);
2343 struct vm_area_struct
*iter_vma
;
2344 struct address_space
*mapping
;
2345 struct prio_tree_iter iter
;
2349 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2350 * from page cache lookup which is in HPAGE_SIZE units.
2352 address
= address
& huge_page_mask(h
);
2353 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
)
2354 + (vma
->vm_pgoff
>> PAGE_SHIFT
);
2355 mapping
= (struct address_space
*)page_private(page
);
2358 * Take the mapping lock for the duration of the table walk. As
2359 * this mapping should be shared between all the VMAs,
2360 * __unmap_hugepage_range() is called as the lock is already held
2362 spin_lock(&mapping
->i_mmap_lock
);
2363 vma_prio_tree_foreach(iter_vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2364 /* Do not unmap the current VMA */
2365 if (iter_vma
== vma
)
2369 * Unmap the page from other VMAs without their own reserves.
2370 * They get marked to be SIGKILLed if they fault in these
2371 * areas. This is because a future no-page fault on this VMA
2372 * could insert a zeroed page instead of the data existing
2373 * from the time of fork. This would look like data corruption
2375 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2376 __unmap_hugepage_range(iter_vma
,
2377 address
, address
+ huge_page_size(h
),
2380 spin_unlock(&mapping
->i_mmap_lock
);
2386 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2388 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2389 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2390 struct page
*pagecache_page
)
2392 struct hstate
*h
= hstate_vma(vma
);
2393 struct page
*old_page
, *new_page
;
2395 int outside_reserve
= 0;
2397 old_page
= pte_page(pte
);
2400 /* If no-one else is actually using this page, avoid the copy
2401 * and just make the page writable */
2402 avoidcopy
= (page_mapcount(old_page
) == 1);
2404 if (PageAnon(old_page
))
2405 page_move_anon_rmap(old_page
, vma
, address
);
2406 set_huge_ptep_writable(vma
, address
, ptep
);
2411 * If the process that created a MAP_PRIVATE mapping is about to
2412 * perform a COW due to a shared page count, attempt to satisfy
2413 * the allocation without using the existing reserves. The pagecache
2414 * page is used to determine if the reserve at this address was
2415 * consumed or not. If reserves were used, a partial faulted mapping
2416 * at the time of fork() could consume its reserves on COW instead
2417 * of the full address range.
2419 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2420 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2421 old_page
!= pagecache_page
)
2422 outside_reserve
= 1;
2424 page_cache_get(old_page
);
2426 /* Drop page_table_lock as buddy allocator may be called */
2427 spin_unlock(&mm
->page_table_lock
);
2428 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2430 if (IS_ERR(new_page
)) {
2431 page_cache_release(old_page
);
2434 * If a process owning a MAP_PRIVATE mapping fails to COW,
2435 * it is due to references held by a child and an insufficient
2436 * huge page pool. To guarantee the original mappers
2437 * reliability, unmap the page from child processes. The child
2438 * may get SIGKILLed if it later faults.
2440 if (outside_reserve
) {
2441 BUG_ON(huge_pte_none(pte
));
2442 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2443 BUG_ON(page_count(old_page
) != 1);
2444 BUG_ON(huge_pte_none(pte
));
2445 spin_lock(&mm
->page_table_lock
);
2446 goto retry_avoidcopy
;
2451 /* Caller expects lock to be held */
2452 spin_lock(&mm
->page_table_lock
);
2453 return -PTR_ERR(new_page
);
2457 * When the original hugepage is shared one, it does not have
2458 * anon_vma prepared.
2460 if (unlikely(anon_vma_prepare(vma
)))
2461 return VM_FAULT_OOM
;
2463 copy_user_huge_page(new_page
, old_page
, address
, vma
);
2464 __SetPageUptodate(new_page
);
2467 * Retake the page_table_lock to check for racing updates
2468 * before the page tables are altered
2470 spin_lock(&mm
->page_table_lock
);
2471 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2472 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2474 mmu_notifier_invalidate_range_start(mm
,
2475 address
& huge_page_mask(h
),
2476 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2477 huge_ptep_clear_flush(vma
, address
, ptep
);
2478 set_huge_pte_at(mm
, address
, ptep
,
2479 make_huge_pte(vma
, new_page
, 1));
2480 page_remove_rmap(old_page
);
2481 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2482 /* Make the old page be freed below */
2483 new_page
= old_page
;
2484 mmu_notifier_invalidate_range_end(mm
,
2485 address
& huge_page_mask(h
),
2486 (address
& huge_page_mask(h
)) + huge_page_size(h
));
2488 page_cache_release(new_page
);
2489 page_cache_release(old_page
);
2493 /* Return the pagecache page at a given address within a VMA */
2494 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2495 struct vm_area_struct
*vma
, unsigned long address
)
2497 struct address_space
*mapping
;
2500 mapping
= vma
->vm_file
->f_mapping
;
2501 idx
= vma_hugecache_offset(h
, vma
, address
);
2503 return find_lock_page(mapping
, idx
);
2507 * Return whether there is a pagecache page to back given address within VMA.
2508 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2510 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2511 struct vm_area_struct
*vma
, unsigned long address
)
2513 struct address_space
*mapping
;
2517 mapping
= vma
->vm_file
->f_mapping
;
2518 idx
= vma_hugecache_offset(h
, vma
, address
);
2520 page
= find_get_page(mapping
, idx
);
2523 return page
!= NULL
;
2526 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2527 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2529 struct hstate
*h
= hstate_vma(vma
);
2530 int ret
= VM_FAULT_SIGBUS
;
2534 struct address_space
*mapping
;
2538 * Currently, we are forced to kill the process in the event the
2539 * original mapper has unmapped pages from the child due to a failed
2540 * COW. Warn that such a situation has occured as it may not be obvious
2542 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2544 "PID %d killed due to inadequate hugepage pool\n",
2549 mapping
= vma
->vm_file
->f_mapping
;
2550 idx
= vma_hugecache_offset(h
, vma
, address
);
2553 * Use page lock to guard against racing truncation
2554 * before we get page_table_lock.
2557 page
= find_lock_page(mapping
, idx
);
2559 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2562 page
= alloc_huge_page(vma
, address
, 0);
2564 ret
= -PTR_ERR(page
);
2567 clear_huge_page(page
, address
, huge_page_size(h
));
2568 __SetPageUptodate(page
);
2570 if (vma
->vm_flags
& VM_MAYSHARE
) {
2572 struct inode
*inode
= mapping
->host
;
2574 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2582 spin_lock(&inode
->i_lock
);
2583 inode
->i_blocks
+= blocks_per_huge_page(h
);
2584 spin_unlock(&inode
->i_lock
);
2585 page_dup_rmap(page
);
2588 if (unlikely(anon_vma_prepare(vma
))) {
2590 goto backout_unlocked
;
2592 hugepage_add_new_anon_rmap(page
, vma
, address
);
2596 * If memory error occurs between mmap() and fault, some process
2597 * don't have hwpoisoned swap entry for errored virtual address.
2598 * So we need to block hugepage fault by PG_hwpoison bit check.
2600 if (unlikely(PageHWPoison(page
))) {
2601 ret
= VM_FAULT_HWPOISON
;
2602 goto backout_unlocked
;
2604 page_dup_rmap(page
);
2608 * If we are going to COW a private mapping later, we examine the
2609 * pending reservations for this page now. This will ensure that
2610 * any allocations necessary to record that reservation occur outside
2613 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2614 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2616 goto backout_unlocked
;
2619 spin_lock(&mm
->page_table_lock
);
2620 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2625 if (!huge_pte_none(huge_ptep_get(ptep
)))
2628 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2629 && (vma
->vm_flags
& VM_SHARED
)));
2630 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2632 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2633 /* Optimization, do the COW without a second fault */
2634 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2637 spin_unlock(&mm
->page_table_lock
);
2643 spin_unlock(&mm
->page_table_lock
);
2650 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2651 unsigned long address
, unsigned int flags
)
2656 struct page
*page
= NULL
;
2657 struct page
*pagecache_page
= NULL
;
2658 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2659 struct hstate
*h
= hstate_vma(vma
);
2661 ptep
= huge_pte_offset(mm
, address
);
2663 entry
= huge_ptep_get(ptep
);
2664 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2665 migration_entry_wait(mm
, (pmd_t
*)ptep
, address
);
2667 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2668 return VM_FAULT_HWPOISON
;
2671 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2673 return VM_FAULT_OOM
;
2676 * Serialize hugepage allocation and instantiation, so that we don't
2677 * get spurious allocation failures if two CPUs race to instantiate
2678 * the same page in the page cache.
2680 mutex_lock(&hugetlb_instantiation_mutex
);
2681 entry
= huge_ptep_get(ptep
);
2682 if (huge_pte_none(entry
)) {
2683 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2690 * If we are going to COW the mapping later, we examine the pending
2691 * reservations for this page now. This will ensure that any
2692 * allocations necessary to record that reservation occur outside the
2693 * spinlock. For private mappings, we also lookup the pagecache
2694 * page now as it is used to determine if a reservation has been
2697 if ((flags
& FAULT_FLAG_WRITE
) && !pte_write(entry
)) {
2698 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2703 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2704 pagecache_page
= hugetlbfs_pagecache_page(h
,
2709 * hugetlb_cow() requires page locks of pte_page(entry) and
2710 * pagecache_page, so here we need take the former one
2711 * when page != pagecache_page or !pagecache_page.
2712 * Note that locking order is always pagecache_page -> page,
2713 * so no worry about deadlock.
2715 page
= pte_page(entry
);
2716 if (page
!= pagecache_page
)
2719 spin_lock(&mm
->page_table_lock
);
2720 /* Check for a racing update before calling hugetlb_cow */
2721 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2722 goto out_page_table_lock
;
2725 if (flags
& FAULT_FLAG_WRITE
) {
2726 if (!pte_write(entry
)) {
2727 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2729 goto out_page_table_lock
;
2731 entry
= pte_mkdirty(entry
);
2733 entry
= pte_mkyoung(entry
);
2734 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2735 flags
& FAULT_FLAG_WRITE
))
2736 update_mmu_cache(vma
, address
, ptep
);
2738 out_page_table_lock
:
2739 spin_unlock(&mm
->page_table_lock
);
2741 if (pagecache_page
) {
2742 unlock_page(pagecache_page
);
2743 put_page(pagecache_page
);
2748 mutex_unlock(&hugetlb_instantiation_mutex
);
2753 /* Can be overriden by architectures */
2754 __attribute__((weak
)) struct page
*
2755 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
2756 pud_t
*pud
, int write
)
2762 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2763 struct page
**pages
, struct vm_area_struct
**vmas
,
2764 unsigned long *position
, int *length
, int i
,
2767 unsigned long pfn_offset
;
2768 unsigned long vaddr
= *position
;
2769 int remainder
= *length
;
2770 struct hstate
*h
= hstate_vma(vma
);
2772 spin_lock(&mm
->page_table_lock
);
2773 while (vaddr
< vma
->vm_end
&& remainder
) {
2779 * Some archs (sparc64, sh*) have multiple pte_ts to
2780 * each hugepage. We have to make sure we get the
2781 * first, for the page indexing below to work.
2783 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2784 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2787 * When coredumping, it suits get_dump_page if we just return
2788 * an error where there's an empty slot with no huge pagecache
2789 * to back it. This way, we avoid allocating a hugepage, and
2790 * the sparse dumpfile avoids allocating disk blocks, but its
2791 * huge holes still show up with zeroes where they need to be.
2793 if (absent
&& (flags
& FOLL_DUMP
) &&
2794 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2800 ((flags
& FOLL_WRITE
) && !pte_write(huge_ptep_get(pte
)))) {
2803 spin_unlock(&mm
->page_table_lock
);
2804 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2805 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2806 spin_lock(&mm
->page_table_lock
);
2807 if (!(ret
& VM_FAULT_ERROR
))
2814 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2815 page
= pte_page(huge_ptep_get(pte
));
2818 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2829 if (vaddr
< vma
->vm_end
&& remainder
&&
2830 pfn_offset
< pages_per_huge_page(h
)) {
2832 * We use pfn_offset to avoid touching the pageframes
2833 * of this compound page.
2838 spin_unlock(&mm
->page_table_lock
);
2839 *length
= remainder
;
2842 return i
? i
: -EFAULT
;
2845 void hugetlb_change_protection(struct vm_area_struct
*vma
,
2846 unsigned long address
, unsigned long end
, pgprot_t newprot
)
2848 struct mm_struct
*mm
= vma
->vm_mm
;
2849 unsigned long start
= address
;
2852 struct hstate
*h
= hstate_vma(vma
);
2854 BUG_ON(address
>= end
);
2855 flush_cache_range(vma
, address
, end
);
2857 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2858 spin_lock(&mm
->page_table_lock
);
2859 for (; address
< end
; address
+= huge_page_size(h
)) {
2860 ptep
= huge_pte_offset(mm
, address
);
2863 if (huge_pmd_unshare(mm
, &address
, ptep
))
2865 if (!huge_pte_none(huge_ptep_get(ptep
))) {
2866 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2867 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
2868 set_huge_pte_at(mm
, address
, ptep
, pte
);
2871 spin_unlock(&mm
->page_table_lock
);
2872 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
2874 flush_tlb_range(vma
, start
, end
);
2877 int hugetlb_reserve_pages(struct inode
*inode
,
2879 struct vm_area_struct
*vma
,
2883 struct hstate
*h
= hstate_inode(inode
);
2886 * Only apply hugepage reservation if asked. At fault time, an
2887 * attempt will be made for VM_NORESERVE to allocate a page
2888 * and filesystem quota without using reserves
2890 if (acctflag
& VM_NORESERVE
)
2894 * Shared mappings base their reservation on the number of pages that
2895 * are already allocated on behalf of the file. Private mappings need
2896 * to reserve the full area even if read-only as mprotect() may be
2897 * called to make the mapping read-write. Assume !vma is a shm mapping
2899 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2900 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
2902 struct resv_map
*resv_map
= resv_map_alloc();
2908 set_vma_resv_map(vma
, resv_map
);
2909 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
2915 /* There must be enough filesystem quota for the mapping */
2916 if (hugetlb_get_quota(inode
->i_mapping
, chg
))
2920 * Check enough hugepages are available for the reservation.
2921 * Hand back the quota if there are not
2923 ret
= hugetlb_acct_memory(h
, chg
);
2925 hugetlb_put_quota(inode
->i_mapping
, chg
);
2930 * Account for the reservations made. Shared mappings record regions
2931 * that have reservations as they are shared by multiple VMAs.
2932 * When the last VMA disappears, the region map says how much
2933 * the reservation was and the page cache tells how much of
2934 * the reservation was consumed. Private mappings are per-VMA and
2935 * only the consumed reservations are tracked. When the VMA
2936 * disappears, the original reservation is the VMA size and the
2937 * consumed reservations are stored in the map. Hence, nothing
2938 * else has to be done for private mappings here
2940 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
2941 region_add(&inode
->i_mapping
->private_list
, from
, to
);
2945 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
2947 struct hstate
*h
= hstate_inode(inode
);
2948 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
2950 spin_lock(&inode
->i_lock
);
2951 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
2952 spin_unlock(&inode
->i_lock
);
2954 hugetlb_put_quota(inode
->i_mapping
, (chg
- freed
));
2955 hugetlb_acct_memory(h
, -(chg
- freed
));
2958 /* Should be called in hugetlb_lock */
2959 static int is_hugepage_on_freelist(struct page
*hpage
)
2963 struct hstate
*h
= page_hstate(hpage
);
2964 int nid
= page_to_nid(hpage
);
2966 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
2972 #ifdef CONFIG_MEMORY_FAILURE
2974 * This function is called from memory failure code.
2975 * Assume the caller holds page lock of the head page.
2977 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
2979 struct hstate
*h
= page_hstate(hpage
);
2980 int nid
= page_to_nid(hpage
);
2983 spin_lock(&hugetlb_lock
);
2984 if (is_hugepage_on_freelist(hpage
)) {
2985 list_del(&hpage
->lru
);
2986 h
->free_huge_pages
--;
2987 h
->free_huge_pages_node
[nid
]--;
2990 spin_unlock(&hugetlb_lock
);