2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, 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>
30 #include <linux/hugetlb.h>
31 #include <linux/hugetlb_cgroup.h>
32 #include <linux/node.h>
35 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
36 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
37 unsigned long hugepages_treat_as_movable
;
39 int hugetlb_max_hstate __read_mostly
;
40 unsigned int default_hstate_idx
;
41 struct hstate hstates
[HUGE_MAX_HSTATE
];
43 __initdata
LIST_HEAD(huge_boot_pages
);
45 /* for command line parsing */
46 static struct hstate
* __initdata parsed_hstate
;
47 static unsigned long __initdata default_hstate_max_huge_pages
;
48 static unsigned long __initdata default_hstate_size
;
51 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
53 DEFINE_SPINLOCK(hugetlb_lock
);
55 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
57 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
59 spin_unlock(&spool
->lock
);
61 /* If no pages are used, and no other handles to the subpool
62 * remain, free the subpool the subpool remain */
67 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
69 struct hugepage_subpool
*spool
;
71 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
75 spin_lock_init(&spool
->lock
);
77 spool
->max_hpages
= nr_blocks
;
78 spool
->used_hpages
= 0;
83 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
85 spin_lock(&spool
->lock
);
86 BUG_ON(!spool
->count
);
88 unlock_or_release_subpool(spool
);
91 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
99 spin_lock(&spool
->lock
);
100 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
101 spool
->used_hpages
+= delta
;
105 spin_unlock(&spool
->lock
);
110 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
116 spin_lock(&spool
->lock
);
117 spool
->used_hpages
-= delta
;
118 /* If hugetlbfs_put_super couldn't free spool due to
119 * an outstanding quota reference, free it now. */
120 unlock_or_release_subpool(spool
);
123 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
125 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
128 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
130 return subpool_inode(file_inode(vma
->vm_file
));
134 * Region tracking -- allows tracking of reservations and instantiated pages
135 * across the pages in a mapping.
137 * The region data structures are protected by a combination of the mmap_sem
138 * and the hugetlb_instantiation_mutex. To access or modify a region the caller
139 * must either hold the mmap_sem for write, or the mmap_sem for read and
140 * the hugetlb_instantiation_mutex:
142 * down_write(&mm->mmap_sem);
144 * down_read(&mm->mmap_sem);
145 * mutex_lock(&hugetlb_instantiation_mutex);
148 struct list_head link
;
153 static long region_add(struct list_head
*head
, long f
, long t
)
155 struct file_region
*rg
, *nrg
, *trg
;
157 /* Locate the region we are either in or before. */
158 list_for_each_entry(rg
, head
, link
)
162 /* Round our left edge to the current segment if it encloses us. */
166 /* Check for and consume any regions we now overlap with. */
168 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
169 if (&rg
->link
== head
)
174 /* If this area reaches higher then extend our area to
175 * include it completely. If this is not the first area
176 * which we intend to reuse, free it. */
189 static long region_chg(struct list_head
*head
, long f
, long t
)
191 struct file_region
*rg
, *nrg
;
194 /* Locate the region we are before or in. */
195 list_for_each_entry(rg
, head
, link
)
199 /* If we are below the current region then a new region is required.
200 * Subtle, allocate a new region at the position but make it zero
201 * size such that we can guarantee to record the reservation. */
202 if (&rg
->link
== head
|| t
< rg
->from
) {
203 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
208 INIT_LIST_HEAD(&nrg
->link
);
209 list_add(&nrg
->link
, rg
->link
.prev
);
214 /* Round our left edge to the current segment if it encloses us. */
219 /* Check for and consume any regions we now overlap with. */
220 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
221 if (&rg
->link
== head
)
226 /* We overlap with this area, if it extends further than
227 * us then we must extend ourselves. Account for its
228 * existing reservation. */
233 chg
-= rg
->to
- rg
->from
;
238 static long region_truncate(struct list_head
*head
, long end
)
240 struct file_region
*rg
, *trg
;
243 /* Locate the region we are either in or before. */
244 list_for_each_entry(rg
, head
, link
)
247 if (&rg
->link
== head
)
250 /* If we are in the middle of a region then adjust it. */
251 if (end
> rg
->from
) {
254 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
257 /* Drop any remaining regions. */
258 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
259 if (&rg
->link
== head
)
261 chg
+= rg
->to
- rg
->from
;
268 static long region_count(struct list_head
*head
, long f
, long t
)
270 struct file_region
*rg
;
273 /* Locate each segment we overlap with, and count that overlap. */
274 list_for_each_entry(rg
, head
, link
) {
283 seg_from
= max(rg
->from
, f
);
284 seg_to
= min(rg
->to
, t
);
286 chg
+= seg_to
- seg_from
;
293 * Convert the address within this vma to the page offset within
294 * the mapping, in pagecache page units; huge pages here.
296 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
297 struct vm_area_struct
*vma
, unsigned long address
)
299 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
300 (vma
->vm_pgoff
>> huge_page_order(h
));
303 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
304 unsigned long address
)
306 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
310 * Return the size of the pages allocated when backing a VMA. In the majority
311 * cases this will be same size as used by the page table entries.
313 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
315 struct hstate
*hstate
;
317 if (!is_vm_hugetlb_page(vma
))
320 hstate
= hstate_vma(vma
);
322 return 1UL << huge_page_shift(hstate
);
324 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
327 * Return the page size being used by the MMU to back a VMA. In the majority
328 * of cases, the page size used by the kernel matches the MMU size. On
329 * architectures where it differs, an architecture-specific version of this
330 * function is required.
332 #ifndef vma_mmu_pagesize
333 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
335 return vma_kernel_pagesize(vma
);
340 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
341 * bits of the reservation map pointer, which are always clear due to
344 #define HPAGE_RESV_OWNER (1UL << 0)
345 #define HPAGE_RESV_UNMAPPED (1UL << 1)
346 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
349 * These helpers are used to track how many pages are reserved for
350 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
351 * is guaranteed to have their future faults succeed.
353 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
354 * the reserve counters are updated with the hugetlb_lock held. It is safe
355 * to reset the VMA at fork() time as it is not in use yet and there is no
356 * chance of the global counters getting corrupted as a result of the values.
358 * The private mapping reservation is represented in a subtly different
359 * manner to a shared mapping. A shared mapping has a region map associated
360 * with the underlying file, this region map represents the backing file
361 * pages which have ever had a reservation assigned which this persists even
362 * after the page is instantiated. A private mapping has a region map
363 * associated with the original mmap which is attached to all VMAs which
364 * reference it, this region map represents those offsets which have consumed
365 * reservation ie. where pages have been instantiated.
367 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
369 return (unsigned long)vma
->vm_private_data
;
372 static void set_vma_private_data(struct vm_area_struct
*vma
,
375 vma
->vm_private_data
= (void *)value
;
380 struct list_head regions
;
383 static struct resv_map
*resv_map_alloc(void)
385 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
389 kref_init(&resv_map
->refs
);
390 INIT_LIST_HEAD(&resv_map
->regions
);
395 static void resv_map_release(struct kref
*ref
)
397 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
399 /* Clear out any active regions before we release the map. */
400 region_truncate(&resv_map
->regions
, 0);
404 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
406 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
407 if (!(vma
->vm_flags
& VM_MAYSHARE
))
408 return (struct resv_map
*)(get_vma_private_data(vma
) &
413 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
415 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
416 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
418 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
419 HPAGE_RESV_MASK
) | (unsigned long)map
);
422 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
424 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
425 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
427 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
430 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
432 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
434 return (get_vma_private_data(vma
) & flag
) != 0;
437 /* Decrement the reserved pages in the hugepage pool by one */
438 static void decrement_hugepage_resv_vma(struct hstate
*h
,
439 struct vm_area_struct
*vma
)
441 if (vma
->vm_flags
& VM_NORESERVE
)
444 if (vma
->vm_flags
& VM_MAYSHARE
) {
445 /* Shared mappings always use reserves */
446 h
->resv_huge_pages
--;
447 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
449 * Only the process that called mmap() has reserves for
452 h
->resv_huge_pages
--;
456 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
457 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
459 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
460 if (!(vma
->vm_flags
& VM_MAYSHARE
))
461 vma
->vm_private_data
= (void *)0;
464 /* Returns true if the VMA has associated reserve pages */
465 static int vma_has_reserves(struct vm_area_struct
*vma
)
467 if (vma
->vm_flags
& VM_NORESERVE
)
469 if (vma
->vm_flags
& VM_MAYSHARE
)
471 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
476 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
479 struct hstate
*h
= page_hstate(src
);
480 struct page
*dst_base
= dst
;
481 struct page
*src_base
= src
;
483 for (i
= 0; i
< pages_per_huge_page(h
); ) {
485 copy_highpage(dst
, src
);
488 dst
= mem_map_next(dst
, dst_base
, i
);
489 src
= mem_map_next(src
, src_base
, i
);
493 void copy_huge_page(struct page
*dst
, struct page
*src
)
496 struct hstate
*h
= page_hstate(src
);
498 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
499 copy_gigantic_page(dst
, src
);
504 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
506 copy_highpage(dst
+ i
, src
+ i
);
510 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
512 int nid
= page_to_nid(page
);
513 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
514 h
->free_huge_pages
++;
515 h
->free_huge_pages_node
[nid
]++;
518 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
522 if (list_empty(&h
->hugepage_freelists
[nid
]))
524 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
525 list_move(&page
->lru
, &h
->hugepage_activelist
);
526 set_page_refcounted(page
);
527 h
->free_huge_pages
--;
528 h
->free_huge_pages_node
[nid
]--;
532 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
533 struct vm_area_struct
*vma
,
534 unsigned long address
, int avoid_reserve
)
536 struct page
*page
= NULL
;
537 struct mempolicy
*mpol
;
538 nodemask_t
*nodemask
;
539 struct zonelist
*zonelist
;
542 unsigned int cpuset_mems_cookie
;
545 * A child process with MAP_PRIVATE mappings created by their parent
546 * have no page reserves. This check ensures that reservations are
547 * not "stolen". The child may still get SIGKILLed
549 if (!vma_has_reserves(vma
) &&
550 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
553 /* If reserves cannot be used, ensure enough pages are in the pool */
554 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
558 cpuset_mems_cookie
= get_mems_allowed();
559 zonelist
= huge_zonelist(vma
, address
,
560 htlb_alloc_mask
, &mpol
, &nodemask
);
562 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
563 MAX_NR_ZONES
- 1, nodemask
) {
564 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
565 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
568 decrement_hugepage_resv_vma(h
, vma
);
575 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
583 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
587 VM_BUG_ON(h
->order
>= MAX_ORDER
);
590 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
591 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
592 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
593 1 << PG_referenced
| 1 << PG_dirty
|
594 1 << PG_active
| 1 << PG_reserved
|
595 1 << PG_private
| 1 << PG_writeback
);
597 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
598 set_compound_page_dtor(page
, NULL
);
599 set_page_refcounted(page
);
600 arch_release_hugepage(page
);
601 __free_pages(page
, huge_page_order(h
));
604 struct hstate
*size_to_hstate(unsigned long size
)
609 if (huge_page_size(h
) == size
)
615 static void free_huge_page(struct page
*page
)
618 * Can't pass hstate in here because it is called from the
619 * compound page destructor.
621 struct hstate
*h
= page_hstate(page
);
622 int nid
= page_to_nid(page
);
623 struct hugepage_subpool
*spool
=
624 (struct hugepage_subpool
*)page_private(page
);
626 set_page_private(page
, 0);
627 page
->mapping
= NULL
;
628 BUG_ON(page_count(page
));
629 BUG_ON(page_mapcount(page
));
631 spin_lock(&hugetlb_lock
);
632 hugetlb_cgroup_uncharge_page(hstate_index(h
),
633 pages_per_huge_page(h
), page
);
634 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
635 /* remove the page from active list */
636 list_del(&page
->lru
);
637 update_and_free_page(h
, page
);
638 h
->surplus_huge_pages
--;
639 h
->surplus_huge_pages_node
[nid
]--;
641 arch_clear_hugepage_flags(page
);
642 enqueue_huge_page(h
, page
);
644 spin_unlock(&hugetlb_lock
);
645 hugepage_subpool_put_pages(spool
, 1);
648 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
650 INIT_LIST_HEAD(&page
->lru
);
651 set_compound_page_dtor(page
, free_huge_page
);
652 spin_lock(&hugetlb_lock
);
653 set_hugetlb_cgroup(page
, NULL
);
655 h
->nr_huge_pages_node
[nid
]++;
656 spin_unlock(&hugetlb_lock
);
657 put_page(page
); /* free it into the hugepage allocator */
660 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
663 int nr_pages
= 1 << order
;
664 struct page
*p
= page
+ 1;
666 /* we rely on prep_new_huge_page to set the destructor */
667 set_compound_order(page
, order
);
669 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
671 set_page_count(p
, 0);
672 p
->first_page
= page
;
677 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
678 * transparent huge pages. See the PageTransHuge() documentation for more
681 int PageHuge(struct page
*page
)
683 compound_page_dtor
*dtor
;
685 if (!PageCompound(page
))
688 page
= compound_head(page
);
689 dtor
= get_compound_page_dtor(page
);
691 return dtor
== free_huge_page
;
693 EXPORT_SYMBOL_GPL(PageHuge
);
695 pgoff_t
__basepage_index(struct page
*page
)
697 struct page
*page_head
= compound_head(page
);
698 pgoff_t index
= page_index(page_head
);
699 unsigned long compound_idx
;
701 if (!PageHuge(page_head
))
702 return page_index(page
);
704 if (compound_order(page_head
) >= MAX_ORDER
)
705 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
707 compound_idx
= page
- page_head
;
709 return (index
<< compound_order(page_head
)) + compound_idx
;
712 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
716 if (h
->order
>= MAX_ORDER
)
719 page
= alloc_pages_exact_node(nid
,
720 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
721 __GFP_REPEAT
|__GFP_NOWARN
,
724 if (arch_prepare_hugepage(page
)) {
725 __free_pages(page
, huge_page_order(h
));
728 prep_new_huge_page(h
, page
, nid
);
735 * common helper functions for hstate_next_node_to_{alloc|free}.
736 * We may have allocated or freed a huge page based on a different
737 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
738 * be outside of *nodes_allowed. Ensure that we use an allowed
739 * node for alloc or free.
741 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
743 nid
= next_node(nid
, *nodes_allowed
);
744 if (nid
== MAX_NUMNODES
)
745 nid
= first_node(*nodes_allowed
);
746 VM_BUG_ON(nid
>= MAX_NUMNODES
);
751 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
753 if (!node_isset(nid
, *nodes_allowed
))
754 nid
= next_node_allowed(nid
, nodes_allowed
);
759 * returns the previously saved node ["this node"] from which to
760 * allocate a persistent huge page for the pool and advance the
761 * next node from which to allocate, handling wrap at end of node
764 static int hstate_next_node_to_alloc(struct hstate
*h
,
765 nodemask_t
*nodes_allowed
)
769 VM_BUG_ON(!nodes_allowed
);
771 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
772 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
778 * helper for free_pool_huge_page() - return the previously saved
779 * node ["this node"] from which to free a huge page. Advance the
780 * next node id whether or not we find a free huge page to free so
781 * that the next attempt to free addresses the next node.
783 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
787 VM_BUG_ON(!nodes_allowed
);
789 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
790 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
795 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
796 for (nr_nodes = nodes_weight(*mask); \
798 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
801 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
802 for (nr_nodes = nodes_weight(*mask); \
804 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
807 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
813 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
814 page
= alloc_fresh_huge_page_node(h
, node
);
822 count_vm_event(HTLB_BUDDY_PGALLOC
);
824 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
830 * Free huge page from pool from next node to free.
831 * Attempt to keep persistent huge pages more or less
832 * balanced over allowed nodes.
833 * Called with hugetlb_lock locked.
835 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
841 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
843 * If we're returning unused surplus pages, only examine
844 * nodes with surplus pages.
846 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
847 !list_empty(&h
->hugepage_freelists
[node
])) {
849 list_entry(h
->hugepage_freelists
[node
].next
,
851 list_del(&page
->lru
);
852 h
->free_huge_pages
--;
853 h
->free_huge_pages_node
[node
]--;
855 h
->surplus_huge_pages
--;
856 h
->surplus_huge_pages_node
[node
]--;
858 update_and_free_page(h
, page
);
867 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
872 if (h
->order
>= MAX_ORDER
)
876 * Assume we will successfully allocate the surplus page to
877 * prevent racing processes from causing the surplus to exceed
880 * This however introduces a different race, where a process B
881 * tries to grow the static hugepage pool while alloc_pages() is
882 * called by process A. B will only examine the per-node
883 * counters in determining if surplus huge pages can be
884 * converted to normal huge pages in adjust_pool_surplus(). A
885 * won't be able to increment the per-node counter, until the
886 * lock is dropped by B, but B doesn't drop hugetlb_lock until
887 * no more huge pages can be converted from surplus to normal
888 * state (and doesn't try to convert again). Thus, we have a
889 * case where a surplus huge page exists, the pool is grown, and
890 * the surplus huge page still exists after, even though it
891 * should just have been converted to a normal huge page. This
892 * does not leak memory, though, as the hugepage will be freed
893 * once it is out of use. It also does not allow the counters to
894 * go out of whack in adjust_pool_surplus() as we don't modify
895 * the node values until we've gotten the hugepage and only the
896 * per-node value is checked there.
898 spin_lock(&hugetlb_lock
);
899 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
900 spin_unlock(&hugetlb_lock
);
904 h
->surplus_huge_pages
++;
906 spin_unlock(&hugetlb_lock
);
908 if (nid
== NUMA_NO_NODE
)
909 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
910 __GFP_REPEAT
|__GFP_NOWARN
,
913 page
= alloc_pages_exact_node(nid
,
914 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
915 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
917 if (page
&& arch_prepare_hugepage(page
)) {
918 __free_pages(page
, huge_page_order(h
));
922 spin_lock(&hugetlb_lock
);
924 INIT_LIST_HEAD(&page
->lru
);
925 r_nid
= page_to_nid(page
);
926 set_compound_page_dtor(page
, free_huge_page
);
927 set_hugetlb_cgroup(page
, NULL
);
929 * We incremented the global counters already
931 h
->nr_huge_pages_node
[r_nid
]++;
932 h
->surplus_huge_pages_node
[r_nid
]++;
933 __count_vm_event(HTLB_BUDDY_PGALLOC
);
936 h
->surplus_huge_pages
--;
937 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
939 spin_unlock(&hugetlb_lock
);
945 * This allocation function is useful in the context where vma is irrelevant.
946 * E.g. soft-offlining uses this function because it only cares physical
947 * address of error page.
949 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
953 spin_lock(&hugetlb_lock
);
954 page
= dequeue_huge_page_node(h
, nid
);
955 spin_unlock(&hugetlb_lock
);
958 page
= alloc_buddy_huge_page(h
, nid
);
964 * Increase the hugetlb pool such that it can accommodate a reservation
967 static int gather_surplus_pages(struct hstate
*h
, int delta
)
969 struct list_head surplus_list
;
970 struct page
*page
, *tmp
;
972 int needed
, allocated
;
973 bool alloc_ok
= true;
975 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
977 h
->resv_huge_pages
+= delta
;
982 INIT_LIST_HEAD(&surplus_list
);
986 spin_unlock(&hugetlb_lock
);
987 for (i
= 0; i
< needed
; i
++) {
988 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
993 list_add(&page
->lru
, &surplus_list
);
998 * After retaking hugetlb_lock, we need to recalculate 'needed'
999 * because either resv_huge_pages or free_huge_pages may have changed.
1001 spin_lock(&hugetlb_lock
);
1002 needed
= (h
->resv_huge_pages
+ delta
) -
1003 (h
->free_huge_pages
+ allocated
);
1008 * We were not able to allocate enough pages to
1009 * satisfy the entire reservation so we free what
1010 * we've allocated so far.
1015 * The surplus_list now contains _at_least_ the number of extra pages
1016 * needed to accommodate the reservation. Add the appropriate number
1017 * of pages to the hugetlb pool and free the extras back to the buddy
1018 * allocator. Commit the entire reservation here to prevent another
1019 * process from stealing the pages as they are added to the pool but
1020 * before they are reserved.
1022 needed
+= allocated
;
1023 h
->resv_huge_pages
+= delta
;
1026 /* Free the needed pages to the hugetlb pool */
1027 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1031 * This page is now managed by the hugetlb allocator and has
1032 * no users -- drop the buddy allocator's reference.
1034 put_page_testzero(page
);
1035 VM_BUG_ON(page_count(page
));
1036 enqueue_huge_page(h
, page
);
1039 spin_unlock(&hugetlb_lock
);
1041 /* Free unnecessary surplus pages to the buddy allocator */
1042 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1044 spin_lock(&hugetlb_lock
);
1050 * When releasing a hugetlb pool reservation, any surplus pages that were
1051 * allocated to satisfy the reservation must be explicitly freed if they were
1053 * Called with hugetlb_lock held.
1055 static void return_unused_surplus_pages(struct hstate
*h
,
1056 unsigned long unused_resv_pages
)
1058 unsigned long nr_pages
;
1060 /* Uncommit the reservation */
1061 h
->resv_huge_pages
-= unused_resv_pages
;
1063 /* Cannot return gigantic pages currently */
1064 if (h
->order
>= MAX_ORDER
)
1067 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1070 * We want to release as many surplus pages as possible, spread
1071 * evenly across all nodes with memory. Iterate across these nodes
1072 * until we can no longer free unreserved surplus pages. This occurs
1073 * when the nodes with surplus pages have no free pages.
1074 * free_pool_huge_page() will balance the the freed pages across the
1075 * on-line nodes with memory and will handle the hstate accounting.
1077 while (nr_pages
--) {
1078 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1084 * Determine if the huge page at addr within the vma has an associated
1085 * reservation. Where it does not we will need to logically increase
1086 * reservation and actually increase subpool usage before an allocation
1087 * can occur. Where any new reservation would be required the
1088 * reservation change is prepared, but not committed. Once the page
1089 * has been allocated from the subpool and instantiated the change should
1090 * be committed via vma_commit_reservation. No action is required on
1093 static long vma_needs_reservation(struct hstate
*h
,
1094 struct vm_area_struct
*vma
, unsigned long addr
)
1096 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1097 struct inode
*inode
= mapping
->host
;
1099 if (vma
->vm_flags
& VM_MAYSHARE
) {
1100 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1101 return region_chg(&inode
->i_mapping
->private_list
,
1104 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1109 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1110 struct resv_map
*reservations
= vma_resv_map(vma
);
1112 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1118 static void vma_commit_reservation(struct hstate
*h
,
1119 struct vm_area_struct
*vma
, unsigned long addr
)
1121 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1122 struct inode
*inode
= mapping
->host
;
1124 if (vma
->vm_flags
& VM_MAYSHARE
) {
1125 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1126 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1128 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1129 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1130 struct resv_map
*reservations
= vma_resv_map(vma
);
1132 /* Mark this page used in the map. */
1133 region_add(&reservations
->regions
, idx
, idx
+ 1);
1137 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1138 unsigned long addr
, int avoid_reserve
)
1140 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1141 struct hstate
*h
= hstate_vma(vma
);
1145 struct hugetlb_cgroup
*h_cg
;
1147 idx
= hstate_index(h
);
1149 * Processes that did not create the mapping will have no
1150 * reserves and will not have accounted against subpool
1151 * limit. Check that the subpool limit can be made before
1152 * satisfying the allocation MAP_NORESERVE mappings may also
1153 * need pages and subpool limit allocated allocated if no reserve
1156 chg
= vma_needs_reservation(h
, vma
, addr
);
1158 return ERR_PTR(-ENOMEM
);
1160 if (hugepage_subpool_get_pages(spool
, chg
))
1161 return ERR_PTR(-ENOSPC
);
1163 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1165 hugepage_subpool_put_pages(spool
, chg
);
1166 return ERR_PTR(-ENOSPC
);
1168 spin_lock(&hugetlb_lock
);
1169 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1171 spin_unlock(&hugetlb_lock
);
1172 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1174 hugetlb_cgroup_uncharge_cgroup(idx
,
1175 pages_per_huge_page(h
),
1177 hugepage_subpool_put_pages(spool
, chg
);
1178 return ERR_PTR(-ENOSPC
);
1180 spin_lock(&hugetlb_lock
);
1181 list_move(&page
->lru
, &h
->hugepage_activelist
);
1184 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1185 spin_unlock(&hugetlb_lock
);
1187 set_page_private(page
, (unsigned long)spool
);
1189 vma_commit_reservation(h
, vma
, addr
);
1193 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1195 struct huge_bootmem_page
*m
;
1198 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1201 addr
= __alloc_bootmem_node_nopanic(NODE_DATA(node
),
1202 huge_page_size(h
), huge_page_size(h
), 0);
1206 * Use the beginning of the huge page to store the
1207 * huge_bootmem_page struct (until gather_bootmem
1208 * puts them into the mem_map).
1217 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1218 /* Put them into a private list first because mem_map is not up yet */
1219 list_add(&m
->list
, &huge_boot_pages
);
1224 static void prep_compound_huge_page(struct page
*page
, int order
)
1226 if (unlikely(order
> (MAX_ORDER
- 1)))
1227 prep_compound_gigantic_page(page
, order
);
1229 prep_compound_page(page
, order
);
1232 /* Put bootmem huge pages into the standard lists after mem_map is up */
1233 static void __init
gather_bootmem_prealloc(void)
1235 struct huge_bootmem_page
*m
;
1237 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1238 struct hstate
*h
= m
->hstate
;
1241 #ifdef CONFIG_HIGHMEM
1242 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1243 free_bootmem_late((unsigned long)m
,
1244 sizeof(struct huge_bootmem_page
));
1246 page
= virt_to_page(m
);
1248 __ClearPageReserved(page
);
1249 WARN_ON(page_count(page
) != 1);
1250 prep_compound_huge_page(page
, h
->order
);
1251 prep_new_huge_page(h
, page
, page_to_nid(page
));
1253 * If we had gigantic hugepages allocated at boot time, we need
1254 * to restore the 'stolen' pages to totalram_pages in order to
1255 * fix confusing memory reports from free(1) and another
1256 * side-effects, like CommitLimit going negative.
1258 if (h
->order
> (MAX_ORDER
- 1))
1259 adjust_managed_page_count(page
, 1 << h
->order
);
1263 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1267 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1268 if (h
->order
>= MAX_ORDER
) {
1269 if (!alloc_bootmem_huge_page(h
))
1271 } else if (!alloc_fresh_huge_page(h
,
1272 &node_states
[N_MEMORY
]))
1275 h
->max_huge_pages
= i
;
1278 static void __init
hugetlb_init_hstates(void)
1282 for_each_hstate(h
) {
1283 /* oversize hugepages were init'ed in early boot */
1284 if (h
->order
< MAX_ORDER
)
1285 hugetlb_hstate_alloc_pages(h
);
1289 static char * __init
memfmt(char *buf
, unsigned long n
)
1291 if (n
>= (1UL << 30))
1292 sprintf(buf
, "%lu GB", n
>> 30);
1293 else if (n
>= (1UL << 20))
1294 sprintf(buf
, "%lu MB", n
>> 20);
1296 sprintf(buf
, "%lu KB", n
>> 10);
1300 static void __init
report_hugepages(void)
1304 for_each_hstate(h
) {
1306 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1307 memfmt(buf
, huge_page_size(h
)),
1308 h
->free_huge_pages
);
1312 #ifdef CONFIG_HIGHMEM
1313 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1314 nodemask_t
*nodes_allowed
)
1318 if (h
->order
>= MAX_ORDER
)
1321 for_each_node_mask(i
, *nodes_allowed
) {
1322 struct page
*page
, *next
;
1323 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1324 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1325 if (count
>= h
->nr_huge_pages
)
1327 if (PageHighMem(page
))
1329 list_del(&page
->lru
);
1330 update_and_free_page(h
, page
);
1331 h
->free_huge_pages
--;
1332 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1337 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1338 nodemask_t
*nodes_allowed
)
1344 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1345 * balanced by operating on them in a round-robin fashion.
1346 * Returns 1 if an adjustment was made.
1348 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1353 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1356 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1357 if (h
->surplus_huge_pages_node
[node
])
1361 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1362 if (h
->surplus_huge_pages_node
[node
] <
1363 h
->nr_huge_pages_node
[node
])
1370 h
->surplus_huge_pages
+= delta
;
1371 h
->surplus_huge_pages_node
[node
] += delta
;
1375 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1376 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1377 nodemask_t
*nodes_allowed
)
1379 unsigned long min_count
, ret
;
1381 if (h
->order
>= MAX_ORDER
)
1382 return h
->max_huge_pages
;
1385 * Increase the pool size
1386 * First take pages out of surplus state. Then make up the
1387 * remaining difference by allocating fresh huge pages.
1389 * We might race with alloc_buddy_huge_page() here and be unable
1390 * to convert a surplus huge page to a normal huge page. That is
1391 * not critical, though, it just means the overall size of the
1392 * pool might be one hugepage larger than it needs to be, but
1393 * within all the constraints specified by the sysctls.
1395 spin_lock(&hugetlb_lock
);
1396 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1397 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1401 while (count
> persistent_huge_pages(h
)) {
1403 * If this allocation races such that we no longer need the
1404 * page, free_huge_page will handle it by freeing the page
1405 * and reducing the surplus.
1407 spin_unlock(&hugetlb_lock
);
1408 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1409 spin_lock(&hugetlb_lock
);
1413 /* Bail for signals. Probably ctrl-c from user */
1414 if (signal_pending(current
))
1419 * Decrease the pool size
1420 * First return free pages to the buddy allocator (being careful
1421 * to keep enough around to satisfy reservations). Then place
1422 * pages into surplus state as needed so the pool will shrink
1423 * to the desired size as pages become free.
1425 * By placing pages into the surplus state independent of the
1426 * overcommit value, we are allowing the surplus pool size to
1427 * exceed overcommit. There are few sane options here. Since
1428 * alloc_buddy_huge_page() is checking the global counter,
1429 * though, we'll note that we're not allowed to exceed surplus
1430 * and won't grow the pool anywhere else. Not until one of the
1431 * sysctls are changed, or the surplus pages go out of use.
1433 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1434 min_count
= max(count
, min_count
);
1435 try_to_free_low(h
, min_count
, nodes_allowed
);
1436 while (min_count
< persistent_huge_pages(h
)) {
1437 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1440 while (count
< persistent_huge_pages(h
)) {
1441 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1445 ret
= persistent_huge_pages(h
);
1446 spin_unlock(&hugetlb_lock
);
1450 #define HSTATE_ATTR_RO(_name) \
1451 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1453 #define HSTATE_ATTR(_name) \
1454 static struct kobj_attribute _name##_attr = \
1455 __ATTR(_name, 0644, _name##_show, _name##_store)
1457 static struct kobject
*hugepages_kobj
;
1458 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1460 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1462 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1466 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1467 if (hstate_kobjs
[i
] == kobj
) {
1469 *nidp
= NUMA_NO_NODE
;
1473 return kobj_to_node_hstate(kobj
, nidp
);
1476 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1477 struct kobj_attribute
*attr
, char *buf
)
1480 unsigned long nr_huge_pages
;
1483 h
= kobj_to_hstate(kobj
, &nid
);
1484 if (nid
== NUMA_NO_NODE
)
1485 nr_huge_pages
= h
->nr_huge_pages
;
1487 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1489 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1492 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1493 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1494 const char *buf
, size_t len
)
1498 unsigned long count
;
1500 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1502 err
= kstrtoul(buf
, 10, &count
);
1506 h
= kobj_to_hstate(kobj
, &nid
);
1507 if (h
->order
>= MAX_ORDER
) {
1512 if (nid
== NUMA_NO_NODE
) {
1514 * global hstate attribute
1516 if (!(obey_mempolicy
&&
1517 init_nodemask_of_mempolicy(nodes_allowed
))) {
1518 NODEMASK_FREE(nodes_allowed
);
1519 nodes_allowed
= &node_states
[N_MEMORY
];
1521 } else if (nodes_allowed
) {
1523 * per node hstate attribute: adjust count to global,
1524 * but restrict alloc/free to the specified node.
1526 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1527 init_nodemask_of_node(nodes_allowed
, nid
);
1529 nodes_allowed
= &node_states
[N_MEMORY
];
1531 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1533 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1534 NODEMASK_FREE(nodes_allowed
);
1538 NODEMASK_FREE(nodes_allowed
);
1542 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1543 struct kobj_attribute
*attr
, char *buf
)
1545 return nr_hugepages_show_common(kobj
, attr
, buf
);
1548 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1549 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1551 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1553 HSTATE_ATTR(nr_hugepages
);
1558 * hstate attribute for optionally mempolicy-based constraint on persistent
1559 * huge page alloc/free.
1561 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1562 struct kobj_attribute
*attr
, char *buf
)
1564 return nr_hugepages_show_common(kobj
, attr
, buf
);
1567 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1568 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1570 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1572 HSTATE_ATTR(nr_hugepages_mempolicy
);
1576 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1577 struct kobj_attribute
*attr
, char *buf
)
1579 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1580 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1583 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1584 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1587 unsigned long input
;
1588 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1590 if (h
->order
>= MAX_ORDER
)
1593 err
= kstrtoul(buf
, 10, &input
);
1597 spin_lock(&hugetlb_lock
);
1598 h
->nr_overcommit_huge_pages
= input
;
1599 spin_unlock(&hugetlb_lock
);
1603 HSTATE_ATTR(nr_overcommit_hugepages
);
1605 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1606 struct kobj_attribute
*attr
, char *buf
)
1609 unsigned long free_huge_pages
;
1612 h
= kobj_to_hstate(kobj
, &nid
);
1613 if (nid
== NUMA_NO_NODE
)
1614 free_huge_pages
= h
->free_huge_pages
;
1616 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1618 return sprintf(buf
, "%lu\n", free_huge_pages
);
1620 HSTATE_ATTR_RO(free_hugepages
);
1622 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1623 struct kobj_attribute
*attr
, char *buf
)
1625 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1626 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1628 HSTATE_ATTR_RO(resv_hugepages
);
1630 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1631 struct kobj_attribute
*attr
, char *buf
)
1634 unsigned long surplus_huge_pages
;
1637 h
= kobj_to_hstate(kobj
, &nid
);
1638 if (nid
== NUMA_NO_NODE
)
1639 surplus_huge_pages
= h
->surplus_huge_pages
;
1641 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1643 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1645 HSTATE_ATTR_RO(surplus_hugepages
);
1647 static struct attribute
*hstate_attrs
[] = {
1648 &nr_hugepages_attr
.attr
,
1649 &nr_overcommit_hugepages_attr
.attr
,
1650 &free_hugepages_attr
.attr
,
1651 &resv_hugepages_attr
.attr
,
1652 &surplus_hugepages_attr
.attr
,
1654 &nr_hugepages_mempolicy_attr
.attr
,
1659 static struct attribute_group hstate_attr_group
= {
1660 .attrs
= hstate_attrs
,
1663 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1664 struct kobject
**hstate_kobjs
,
1665 struct attribute_group
*hstate_attr_group
)
1668 int hi
= hstate_index(h
);
1670 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1671 if (!hstate_kobjs
[hi
])
1674 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1676 kobject_put(hstate_kobjs
[hi
]);
1681 static void __init
hugetlb_sysfs_init(void)
1686 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1687 if (!hugepages_kobj
)
1690 for_each_hstate(h
) {
1691 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1692 hstate_kobjs
, &hstate_attr_group
);
1694 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1701 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1702 * with node devices in node_devices[] using a parallel array. The array
1703 * index of a node device or _hstate == node id.
1704 * This is here to avoid any static dependency of the node device driver, in
1705 * the base kernel, on the hugetlb module.
1707 struct node_hstate
{
1708 struct kobject
*hugepages_kobj
;
1709 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1711 struct node_hstate node_hstates
[MAX_NUMNODES
];
1714 * A subset of global hstate attributes for node devices
1716 static struct attribute
*per_node_hstate_attrs
[] = {
1717 &nr_hugepages_attr
.attr
,
1718 &free_hugepages_attr
.attr
,
1719 &surplus_hugepages_attr
.attr
,
1723 static struct attribute_group per_node_hstate_attr_group
= {
1724 .attrs
= per_node_hstate_attrs
,
1728 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1729 * Returns node id via non-NULL nidp.
1731 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1735 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1736 struct node_hstate
*nhs
= &node_hstates
[nid
];
1738 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1739 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1751 * Unregister hstate attributes from a single node device.
1752 * No-op if no hstate attributes attached.
1754 static void hugetlb_unregister_node(struct node
*node
)
1757 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1759 if (!nhs
->hugepages_kobj
)
1760 return; /* no hstate attributes */
1762 for_each_hstate(h
) {
1763 int idx
= hstate_index(h
);
1764 if (nhs
->hstate_kobjs
[idx
]) {
1765 kobject_put(nhs
->hstate_kobjs
[idx
]);
1766 nhs
->hstate_kobjs
[idx
] = NULL
;
1770 kobject_put(nhs
->hugepages_kobj
);
1771 nhs
->hugepages_kobj
= NULL
;
1775 * hugetlb module exit: unregister hstate attributes from node devices
1778 static void hugetlb_unregister_all_nodes(void)
1783 * disable node device registrations.
1785 register_hugetlbfs_with_node(NULL
, NULL
);
1788 * remove hstate attributes from any nodes that have them.
1790 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1791 hugetlb_unregister_node(node_devices
[nid
]);
1795 * Register hstate attributes for a single node device.
1796 * No-op if attributes already registered.
1798 static void hugetlb_register_node(struct node
*node
)
1801 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1804 if (nhs
->hugepages_kobj
)
1805 return; /* already allocated */
1807 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1809 if (!nhs
->hugepages_kobj
)
1812 for_each_hstate(h
) {
1813 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1815 &per_node_hstate_attr_group
);
1817 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1818 h
->name
, node
->dev
.id
);
1819 hugetlb_unregister_node(node
);
1826 * hugetlb init time: register hstate attributes for all registered node
1827 * devices of nodes that have memory. All on-line nodes should have
1828 * registered their associated device by this time.
1830 static void hugetlb_register_all_nodes(void)
1834 for_each_node_state(nid
, N_MEMORY
) {
1835 struct node
*node
= node_devices
[nid
];
1836 if (node
->dev
.id
== nid
)
1837 hugetlb_register_node(node
);
1841 * Let the node device driver know we're here so it can
1842 * [un]register hstate attributes on node hotplug.
1844 register_hugetlbfs_with_node(hugetlb_register_node
,
1845 hugetlb_unregister_node
);
1847 #else /* !CONFIG_NUMA */
1849 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1857 static void hugetlb_unregister_all_nodes(void) { }
1859 static void hugetlb_register_all_nodes(void) { }
1863 static void __exit
hugetlb_exit(void)
1867 hugetlb_unregister_all_nodes();
1869 for_each_hstate(h
) {
1870 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1873 kobject_put(hugepages_kobj
);
1875 module_exit(hugetlb_exit
);
1877 static int __init
hugetlb_init(void)
1879 /* Some platform decide whether they support huge pages at boot
1880 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1881 * there is no such support
1883 if (HPAGE_SHIFT
== 0)
1886 if (!size_to_hstate(default_hstate_size
)) {
1887 default_hstate_size
= HPAGE_SIZE
;
1888 if (!size_to_hstate(default_hstate_size
))
1889 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1891 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1892 if (default_hstate_max_huge_pages
)
1893 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1895 hugetlb_init_hstates();
1896 gather_bootmem_prealloc();
1899 hugetlb_sysfs_init();
1900 hugetlb_register_all_nodes();
1901 hugetlb_cgroup_file_init();
1905 module_init(hugetlb_init
);
1907 /* Should be called on processing a hugepagesz=... option */
1908 void __init
hugetlb_add_hstate(unsigned order
)
1913 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1914 pr_warning("hugepagesz= specified twice, ignoring\n");
1917 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1919 h
= &hstates
[hugetlb_max_hstate
++];
1921 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1922 h
->nr_huge_pages
= 0;
1923 h
->free_huge_pages
= 0;
1924 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1925 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1926 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1927 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
1928 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
1929 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1930 huge_page_size(h
)/1024);
1935 static int __init
hugetlb_nrpages_setup(char *s
)
1938 static unsigned long *last_mhp
;
1941 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1942 * so this hugepages= parameter goes to the "default hstate".
1944 if (!hugetlb_max_hstate
)
1945 mhp
= &default_hstate_max_huge_pages
;
1947 mhp
= &parsed_hstate
->max_huge_pages
;
1949 if (mhp
== last_mhp
) {
1950 pr_warning("hugepages= specified twice without "
1951 "interleaving hugepagesz=, ignoring\n");
1955 if (sscanf(s
, "%lu", mhp
) <= 0)
1959 * Global state is always initialized later in hugetlb_init.
1960 * But we need to allocate >= MAX_ORDER hstates here early to still
1961 * use the bootmem allocator.
1963 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1964 hugetlb_hstate_alloc_pages(parsed_hstate
);
1970 __setup("hugepages=", hugetlb_nrpages_setup
);
1972 static int __init
hugetlb_default_setup(char *s
)
1974 default_hstate_size
= memparse(s
, &s
);
1977 __setup("default_hugepagesz=", hugetlb_default_setup
);
1979 static unsigned int cpuset_mems_nr(unsigned int *array
)
1982 unsigned int nr
= 0;
1984 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1990 #ifdef CONFIG_SYSCTL
1991 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1992 struct ctl_table
*table
, int write
,
1993 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1995 struct hstate
*h
= &default_hstate
;
1999 tmp
= h
->max_huge_pages
;
2001 if (write
&& h
->order
>= MAX_ORDER
)
2005 table
->maxlen
= sizeof(unsigned long);
2006 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2011 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2012 GFP_KERNEL
| __GFP_NORETRY
);
2013 if (!(obey_mempolicy
&&
2014 init_nodemask_of_mempolicy(nodes_allowed
))) {
2015 NODEMASK_FREE(nodes_allowed
);
2016 nodes_allowed
= &node_states
[N_MEMORY
];
2018 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2020 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2021 NODEMASK_FREE(nodes_allowed
);
2027 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2028 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2031 return hugetlb_sysctl_handler_common(false, table
, write
,
2032 buffer
, length
, ppos
);
2036 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2037 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2039 return hugetlb_sysctl_handler_common(true, table
, write
,
2040 buffer
, length
, ppos
);
2042 #endif /* CONFIG_NUMA */
2044 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2045 void __user
*buffer
,
2046 size_t *length
, loff_t
*ppos
)
2048 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2049 if (hugepages_treat_as_movable
)
2050 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2052 htlb_alloc_mask
= GFP_HIGHUSER
;
2056 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2057 void __user
*buffer
,
2058 size_t *length
, loff_t
*ppos
)
2060 struct hstate
*h
= &default_hstate
;
2064 tmp
= h
->nr_overcommit_huge_pages
;
2066 if (write
&& h
->order
>= MAX_ORDER
)
2070 table
->maxlen
= sizeof(unsigned long);
2071 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2076 spin_lock(&hugetlb_lock
);
2077 h
->nr_overcommit_huge_pages
= tmp
;
2078 spin_unlock(&hugetlb_lock
);
2084 #endif /* CONFIG_SYSCTL */
2086 void hugetlb_report_meminfo(struct seq_file
*m
)
2088 struct hstate
*h
= &default_hstate
;
2090 "HugePages_Total: %5lu\n"
2091 "HugePages_Free: %5lu\n"
2092 "HugePages_Rsvd: %5lu\n"
2093 "HugePages_Surp: %5lu\n"
2094 "Hugepagesize: %8lu kB\n",
2098 h
->surplus_huge_pages
,
2099 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2102 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2104 struct hstate
*h
= &default_hstate
;
2106 "Node %d HugePages_Total: %5u\n"
2107 "Node %d HugePages_Free: %5u\n"
2108 "Node %d HugePages_Surp: %5u\n",
2109 nid
, h
->nr_huge_pages_node
[nid
],
2110 nid
, h
->free_huge_pages_node
[nid
],
2111 nid
, h
->surplus_huge_pages_node
[nid
]);
2114 void hugetlb_show_meminfo(void)
2119 for_each_node_state(nid
, N_MEMORY
)
2121 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2123 h
->nr_huge_pages_node
[nid
],
2124 h
->free_huge_pages_node
[nid
],
2125 h
->surplus_huge_pages_node
[nid
],
2126 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2129 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2130 unsigned long hugetlb_total_pages(void)
2133 unsigned long nr_total_pages
= 0;
2136 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2137 return nr_total_pages
;
2140 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2144 spin_lock(&hugetlb_lock
);
2146 * When cpuset is configured, it breaks the strict hugetlb page
2147 * reservation as the accounting is done on a global variable. Such
2148 * reservation is completely rubbish in the presence of cpuset because
2149 * the reservation is not checked against page availability for the
2150 * current cpuset. Application can still potentially OOM'ed by kernel
2151 * with lack of free htlb page in cpuset that the task is in.
2152 * Attempt to enforce strict accounting with cpuset is almost
2153 * impossible (or too ugly) because cpuset is too fluid that
2154 * task or memory node can be dynamically moved between cpusets.
2156 * The change of semantics for shared hugetlb mapping with cpuset is
2157 * undesirable. However, in order to preserve some of the semantics,
2158 * we fall back to check against current free page availability as
2159 * a best attempt and hopefully to minimize the impact of changing
2160 * semantics that cpuset has.
2163 if (gather_surplus_pages(h
, delta
) < 0)
2166 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2167 return_unused_surplus_pages(h
, delta
);
2174 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2177 spin_unlock(&hugetlb_lock
);
2181 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2183 struct resv_map
*reservations
= vma_resv_map(vma
);
2186 * This new VMA should share its siblings reservation map if present.
2187 * The VMA will only ever have a valid reservation map pointer where
2188 * it is being copied for another still existing VMA. As that VMA
2189 * has a reference to the reservation map it cannot disappear until
2190 * after this open call completes. It is therefore safe to take a
2191 * new reference here without additional locking.
2194 kref_get(&reservations
->refs
);
2197 static void resv_map_put(struct vm_area_struct
*vma
)
2199 struct resv_map
*reservations
= vma_resv_map(vma
);
2203 kref_put(&reservations
->refs
, resv_map_release
);
2206 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2208 struct hstate
*h
= hstate_vma(vma
);
2209 struct resv_map
*reservations
= vma_resv_map(vma
);
2210 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2211 unsigned long reserve
;
2212 unsigned long start
;
2216 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2217 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2219 reserve
= (end
- start
) -
2220 region_count(&reservations
->regions
, start
, end
);
2225 hugetlb_acct_memory(h
, -reserve
);
2226 hugepage_subpool_put_pages(spool
, reserve
);
2232 * We cannot handle pagefaults against hugetlb pages at all. They cause
2233 * handle_mm_fault() to try to instantiate regular-sized pages in the
2234 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2237 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2243 const struct vm_operations_struct hugetlb_vm_ops
= {
2244 .fault
= hugetlb_vm_op_fault
,
2245 .open
= hugetlb_vm_op_open
,
2246 .close
= hugetlb_vm_op_close
,
2249 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2255 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2256 vma
->vm_page_prot
)));
2258 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2259 vma
->vm_page_prot
));
2261 entry
= pte_mkyoung(entry
);
2262 entry
= pte_mkhuge(entry
);
2263 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2268 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2269 unsigned long address
, pte_t
*ptep
)
2273 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2274 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2275 update_mmu_cache(vma
, address
, ptep
);
2279 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2280 struct vm_area_struct
*vma
)
2282 pte_t
*src_pte
, *dst_pte
, entry
;
2283 struct page
*ptepage
;
2286 struct hstate
*h
= hstate_vma(vma
);
2287 unsigned long sz
= huge_page_size(h
);
2289 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2291 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2292 src_pte
= huge_pte_offset(src
, addr
);
2295 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2299 /* If the pagetables are shared don't copy or take references */
2300 if (dst_pte
== src_pte
)
2303 spin_lock(&dst
->page_table_lock
);
2304 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2305 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2307 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2308 entry
= huge_ptep_get(src_pte
);
2309 ptepage
= pte_page(entry
);
2311 page_dup_rmap(ptepage
);
2312 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2314 spin_unlock(&src
->page_table_lock
);
2315 spin_unlock(&dst
->page_table_lock
);
2323 static int is_hugetlb_entry_migration(pte_t pte
)
2327 if (huge_pte_none(pte
) || pte_present(pte
))
2329 swp
= pte_to_swp_entry(pte
);
2330 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2336 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2340 if (huge_pte_none(pte
) || pte_present(pte
))
2342 swp
= pte_to_swp_entry(pte
);
2343 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2349 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2350 unsigned long start
, unsigned long end
,
2351 struct page
*ref_page
)
2353 int force_flush
= 0;
2354 struct mm_struct
*mm
= vma
->vm_mm
;
2355 unsigned long address
;
2359 struct hstate
*h
= hstate_vma(vma
);
2360 unsigned long sz
= huge_page_size(h
);
2361 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2362 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2364 WARN_ON(!is_vm_hugetlb_page(vma
));
2365 BUG_ON(start
& ~huge_page_mask(h
));
2366 BUG_ON(end
& ~huge_page_mask(h
));
2368 tlb_start_vma(tlb
, vma
);
2369 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2371 spin_lock(&mm
->page_table_lock
);
2372 for (address
= start
; address
< end
; address
+= sz
) {
2373 ptep
= huge_pte_offset(mm
, address
);
2377 if (huge_pmd_unshare(mm
, &address
, ptep
))
2380 pte
= huge_ptep_get(ptep
);
2381 if (huge_pte_none(pte
))
2385 * HWPoisoned hugepage is already unmapped and dropped reference
2387 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2388 huge_pte_clear(mm
, address
, ptep
);
2392 page
= pte_page(pte
);
2394 * If a reference page is supplied, it is because a specific
2395 * page is being unmapped, not a range. Ensure the page we
2396 * are about to unmap is the actual page of interest.
2399 if (page
!= ref_page
)
2403 * Mark the VMA as having unmapped its page so that
2404 * future faults in this VMA will fail rather than
2405 * looking like data was lost
2407 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2410 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2411 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2412 if (huge_pte_dirty(pte
))
2413 set_page_dirty(page
);
2415 page_remove_rmap(page
);
2416 force_flush
= !__tlb_remove_page(tlb
, page
);
2419 /* Bail out after unmapping reference page if supplied */
2423 spin_unlock(&mm
->page_table_lock
);
2425 * mmu_gather ran out of room to batch pages, we break out of
2426 * the PTE lock to avoid doing the potential expensive TLB invalidate
2427 * and page-free while holding it.
2432 if (address
< end
&& !ref_page
)
2435 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2436 tlb_end_vma(tlb
, vma
);
2439 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2440 struct vm_area_struct
*vma
, unsigned long start
,
2441 unsigned long end
, struct page
*ref_page
)
2443 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2446 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2447 * test will fail on a vma being torn down, and not grab a page table
2448 * on its way out. We're lucky that the flag has such an appropriate
2449 * name, and can in fact be safely cleared here. We could clear it
2450 * before the __unmap_hugepage_range above, but all that's necessary
2451 * is to clear it before releasing the i_mmap_mutex. This works
2452 * because in the context this is called, the VMA is about to be
2453 * destroyed and the i_mmap_mutex is held.
2455 vma
->vm_flags
&= ~VM_MAYSHARE
;
2458 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2459 unsigned long end
, struct page
*ref_page
)
2461 struct mm_struct
*mm
;
2462 struct mmu_gather tlb
;
2466 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2467 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2468 tlb_finish_mmu(&tlb
, start
, end
);
2472 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2473 * mappping it owns the reserve page for. The intention is to unmap the page
2474 * from other VMAs and let the children be SIGKILLed if they are faulting the
2477 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2478 struct page
*page
, unsigned long address
)
2480 struct hstate
*h
= hstate_vma(vma
);
2481 struct vm_area_struct
*iter_vma
;
2482 struct address_space
*mapping
;
2486 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2487 * from page cache lookup which is in HPAGE_SIZE units.
2489 address
= address
& huge_page_mask(h
);
2490 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2492 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2495 * Take the mapping lock for the duration of the table walk. As
2496 * this mapping should be shared between all the VMAs,
2497 * __unmap_hugepage_range() is called as the lock is already held
2499 mutex_lock(&mapping
->i_mmap_mutex
);
2500 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2501 /* Do not unmap the current VMA */
2502 if (iter_vma
== vma
)
2506 * Unmap the page from other VMAs without their own reserves.
2507 * They get marked to be SIGKILLed if they fault in these
2508 * areas. This is because a future no-page fault on this VMA
2509 * could insert a zeroed page instead of the data existing
2510 * from the time of fork. This would look like data corruption
2512 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2513 unmap_hugepage_range(iter_vma
, address
,
2514 address
+ huge_page_size(h
), page
);
2516 mutex_unlock(&mapping
->i_mmap_mutex
);
2522 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2523 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2524 * cannot race with other handlers or page migration.
2525 * Keep the pte_same checks anyway to make transition from the mutex easier.
2527 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2528 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2529 struct page
*pagecache_page
)
2531 struct hstate
*h
= hstate_vma(vma
);
2532 struct page
*old_page
, *new_page
;
2533 int outside_reserve
= 0;
2534 unsigned long mmun_start
; /* For mmu_notifiers */
2535 unsigned long mmun_end
; /* For mmu_notifiers */
2537 old_page
= pte_page(pte
);
2540 /* If no-one else is actually using this page, avoid the copy
2541 * and just make the page writable */
2542 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2543 page_move_anon_rmap(old_page
, vma
, address
);
2544 set_huge_ptep_writable(vma
, address
, ptep
);
2549 * If the process that created a MAP_PRIVATE mapping is about to
2550 * perform a COW due to a shared page count, attempt to satisfy
2551 * the allocation without using the existing reserves. The pagecache
2552 * page is used to determine if the reserve at this address was
2553 * consumed or not. If reserves were used, a partial faulted mapping
2554 * at the time of fork() could consume its reserves on COW instead
2555 * of the full address range.
2557 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2558 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2559 old_page
!= pagecache_page
)
2560 outside_reserve
= 1;
2562 page_cache_get(old_page
);
2564 /* Drop page_table_lock as buddy allocator may be called */
2565 spin_unlock(&mm
->page_table_lock
);
2566 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2568 if (IS_ERR(new_page
)) {
2569 long err
= PTR_ERR(new_page
);
2570 page_cache_release(old_page
);
2573 * If a process owning a MAP_PRIVATE mapping fails to COW,
2574 * it is due to references held by a child and an insufficient
2575 * huge page pool. To guarantee the original mappers
2576 * reliability, unmap the page from child processes. The child
2577 * may get SIGKILLed if it later faults.
2579 if (outside_reserve
) {
2580 BUG_ON(huge_pte_none(pte
));
2581 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2582 BUG_ON(huge_pte_none(pte
));
2583 spin_lock(&mm
->page_table_lock
);
2584 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2585 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2586 goto retry_avoidcopy
;
2588 * race occurs while re-acquiring page_table_lock, and
2596 /* Caller expects lock to be held */
2597 spin_lock(&mm
->page_table_lock
);
2599 return VM_FAULT_OOM
;
2601 return VM_FAULT_SIGBUS
;
2605 * When the original hugepage is shared one, it does not have
2606 * anon_vma prepared.
2608 if (unlikely(anon_vma_prepare(vma
))) {
2609 page_cache_release(new_page
);
2610 page_cache_release(old_page
);
2611 /* Caller expects lock to be held */
2612 spin_lock(&mm
->page_table_lock
);
2613 return VM_FAULT_OOM
;
2616 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2617 pages_per_huge_page(h
));
2618 __SetPageUptodate(new_page
);
2620 mmun_start
= address
& huge_page_mask(h
);
2621 mmun_end
= mmun_start
+ huge_page_size(h
);
2622 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2624 * Retake the page_table_lock to check for racing updates
2625 * before the page tables are altered
2627 spin_lock(&mm
->page_table_lock
);
2628 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2629 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2631 huge_ptep_clear_flush(vma
, address
, ptep
);
2632 set_huge_pte_at(mm
, address
, ptep
,
2633 make_huge_pte(vma
, new_page
, 1));
2634 page_remove_rmap(old_page
);
2635 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2636 /* Make the old page be freed below */
2637 new_page
= old_page
;
2639 spin_unlock(&mm
->page_table_lock
);
2640 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2641 /* Caller expects lock to be held */
2642 spin_lock(&mm
->page_table_lock
);
2643 page_cache_release(new_page
);
2644 page_cache_release(old_page
);
2648 /* Return the pagecache page at a given address within a VMA */
2649 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2650 struct vm_area_struct
*vma
, unsigned long address
)
2652 struct address_space
*mapping
;
2655 mapping
= vma
->vm_file
->f_mapping
;
2656 idx
= vma_hugecache_offset(h
, vma
, address
);
2658 return find_lock_page(mapping
, idx
);
2662 * Return whether there is a pagecache page to back given address within VMA.
2663 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2665 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2666 struct vm_area_struct
*vma
, unsigned long address
)
2668 struct address_space
*mapping
;
2672 mapping
= vma
->vm_file
->f_mapping
;
2673 idx
= vma_hugecache_offset(h
, vma
, address
);
2675 page
= find_get_page(mapping
, idx
);
2678 return page
!= NULL
;
2681 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2682 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2684 struct hstate
*h
= hstate_vma(vma
);
2685 int ret
= VM_FAULT_SIGBUS
;
2690 struct address_space
*mapping
;
2694 * Currently, we are forced to kill the process in the event the
2695 * original mapper has unmapped pages from the child due to a failed
2696 * COW. Warn that such a situation has occurred as it may not be obvious
2698 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2699 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2704 mapping
= vma
->vm_file
->f_mapping
;
2705 idx
= vma_hugecache_offset(h
, vma
, address
);
2708 * Use page lock to guard against racing truncation
2709 * before we get page_table_lock.
2712 page
= find_lock_page(mapping
, idx
);
2714 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2717 page
= alloc_huge_page(vma
, address
, 0);
2719 ret
= PTR_ERR(page
);
2723 ret
= VM_FAULT_SIGBUS
;
2726 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2727 __SetPageUptodate(page
);
2729 if (vma
->vm_flags
& VM_MAYSHARE
) {
2731 struct inode
*inode
= mapping
->host
;
2733 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2741 spin_lock(&inode
->i_lock
);
2742 inode
->i_blocks
+= blocks_per_huge_page(h
);
2743 spin_unlock(&inode
->i_lock
);
2746 if (unlikely(anon_vma_prepare(vma
))) {
2748 goto backout_unlocked
;
2754 * If memory error occurs between mmap() and fault, some process
2755 * don't have hwpoisoned swap entry for errored virtual address.
2756 * So we need to block hugepage fault by PG_hwpoison bit check.
2758 if (unlikely(PageHWPoison(page
))) {
2759 ret
= VM_FAULT_HWPOISON
|
2760 VM_FAULT_SET_HINDEX(hstate_index(h
));
2761 goto backout_unlocked
;
2766 * If we are going to COW a private mapping later, we examine the
2767 * pending reservations for this page now. This will ensure that
2768 * any allocations necessary to record that reservation occur outside
2771 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2772 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2774 goto backout_unlocked
;
2777 spin_lock(&mm
->page_table_lock
);
2778 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2783 if (!huge_pte_none(huge_ptep_get(ptep
)))
2787 hugepage_add_new_anon_rmap(page
, vma
, address
);
2789 page_dup_rmap(page
);
2790 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2791 && (vma
->vm_flags
& VM_SHARED
)));
2792 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2794 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2795 /* Optimization, do the COW without a second fault */
2796 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2799 spin_unlock(&mm
->page_table_lock
);
2805 spin_unlock(&mm
->page_table_lock
);
2812 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2813 unsigned long address
, unsigned int flags
)
2818 struct page
*page
= NULL
;
2819 struct page
*pagecache_page
= NULL
;
2820 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2821 struct hstate
*h
= hstate_vma(vma
);
2823 address
&= huge_page_mask(h
);
2825 ptep
= huge_pte_offset(mm
, address
);
2827 entry
= huge_ptep_get(ptep
);
2828 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2829 migration_entry_wait_huge(mm
, ptep
);
2831 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2832 return VM_FAULT_HWPOISON_LARGE
|
2833 VM_FAULT_SET_HINDEX(hstate_index(h
));
2836 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2838 return VM_FAULT_OOM
;
2841 * Serialize hugepage allocation and instantiation, so that we don't
2842 * get spurious allocation failures if two CPUs race to instantiate
2843 * the same page in the page cache.
2845 mutex_lock(&hugetlb_instantiation_mutex
);
2846 entry
= huge_ptep_get(ptep
);
2847 if (huge_pte_none(entry
)) {
2848 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2855 * If we are going to COW the mapping later, we examine the pending
2856 * reservations for this page now. This will ensure that any
2857 * allocations necessary to record that reservation occur outside the
2858 * spinlock. For private mappings, we also lookup the pagecache
2859 * page now as it is used to determine if a reservation has been
2862 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
2863 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2868 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2869 pagecache_page
= hugetlbfs_pagecache_page(h
,
2874 * hugetlb_cow() requires page locks of pte_page(entry) and
2875 * pagecache_page, so here we need take the former one
2876 * when page != pagecache_page or !pagecache_page.
2877 * Note that locking order is always pagecache_page -> page,
2878 * so no worry about deadlock.
2880 page
= pte_page(entry
);
2882 if (page
!= pagecache_page
)
2885 spin_lock(&mm
->page_table_lock
);
2886 /* Check for a racing update before calling hugetlb_cow */
2887 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2888 goto out_page_table_lock
;
2891 if (flags
& FAULT_FLAG_WRITE
) {
2892 if (!huge_pte_write(entry
)) {
2893 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2895 goto out_page_table_lock
;
2897 entry
= huge_pte_mkdirty(entry
);
2899 entry
= pte_mkyoung(entry
);
2900 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2901 flags
& FAULT_FLAG_WRITE
))
2902 update_mmu_cache(vma
, address
, ptep
);
2904 out_page_table_lock
:
2905 spin_unlock(&mm
->page_table_lock
);
2907 if (pagecache_page
) {
2908 unlock_page(pagecache_page
);
2909 put_page(pagecache_page
);
2911 if (page
!= pagecache_page
)
2916 mutex_unlock(&hugetlb_instantiation_mutex
);
2921 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2922 struct page
**pages
, struct vm_area_struct
**vmas
,
2923 unsigned long *position
, unsigned long *nr_pages
,
2924 long i
, unsigned int flags
)
2926 unsigned long pfn_offset
;
2927 unsigned long vaddr
= *position
;
2928 unsigned long remainder
= *nr_pages
;
2929 struct hstate
*h
= hstate_vma(vma
);
2931 spin_lock(&mm
->page_table_lock
);
2932 while (vaddr
< vma
->vm_end
&& remainder
) {
2938 * Some archs (sparc64, sh*) have multiple pte_ts to
2939 * each hugepage. We have to make sure we get the
2940 * first, for the page indexing below to work.
2942 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2943 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2946 * When coredumping, it suits get_dump_page if we just return
2947 * an error where there's an empty slot with no huge pagecache
2948 * to back it. This way, we avoid allocating a hugepage, and
2949 * the sparse dumpfile avoids allocating disk blocks, but its
2950 * huge holes still show up with zeroes where they need to be.
2952 if (absent
&& (flags
& FOLL_DUMP
) &&
2953 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2959 * We need call hugetlb_fault for both hugepages under migration
2960 * (in which case hugetlb_fault waits for the migration,) and
2961 * hwpoisoned hugepages (in which case we need to prevent the
2962 * caller from accessing to them.) In order to do this, we use
2963 * here is_swap_pte instead of is_hugetlb_entry_migration and
2964 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
2965 * both cases, and because we can't follow correct pages
2966 * directly from any kind of swap entries.
2968 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
2969 ((flags
& FOLL_WRITE
) &&
2970 !huge_pte_write(huge_ptep_get(pte
)))) {
2973 spin_unlock(&mm
->page_table_lock
);
2974 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2975 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2976 spin_lock(&mm
->page_table_lock
);
2977 if (!(ret
& VM_FAULT_ERROR
))
2984 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2985 page
= pte_page(huge_ptep_get(pte
));
2988 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2999 if (vaddr
< vma
->vm_end
&& remainder
&&
3000 pfn_offset
< pages_per_huge_page(h
)) {
3002 * We use pfn_offset to avoid touching the pageframes
3003 * of this compound page.
3008 spin_unlock(&mm
->page_table_lock
);
3009 *nr_pages
= remainder
;
3012 return i
? i
: -EFAULT
;
3015 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3016 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3018 struct mm_struct
*mm
= vma
->vm_mm
;
3019 unsigned long start
= address
;
3022 struct hstate
*h
= hstate_vma(vma
);
3023 unsigned long pages
= 0;
3025 BUG_ON(address
>= end
);
3026 flush_cache_range(vma
, address
, end
);
3028 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3029 spin_lock(&mm
->page_table_lock
);
3030 for (; address
< end
; address
+= huge_page_size(h
)) {
3031 ptep
= huge_pte_offset(mm
, address
);
3034 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3038 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3039 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3040 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3041 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3042 set_huge_pte_at(mm
, address
, ptep
, pte
);
3046 spin_unlock(&mm
->page_table_lock
);
3048 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3049 * may have cleared our pud entry and done put_page on the page table:
3050 * once we release i_mmap_mutex, another task can do the final put_page
3051 * and that page table be reused and filled with junk.
3053 flush_tlb_range(vma
, start
, end
);
3054 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3056 return pages
<< h
->order
;
3059 int hugetlb_reserve_pages(struct inode
*inode
,
3061 struct vm_area_struct
*vma
,
3062 vm_flags_t vm_flags
)
3065 struct hstate
*h
= hstate_inode(inode
);
3066 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3069 * Only apply hugepage reservation if asked. At fault time, an
3070 * attempt will be made for VM_NORESERVE to allocate a page
3071 * without using reserves
3073 if (vm_flags
& VM_NORESERVE
)
3077 * Shared mappings base their reservation on the number of pages that
3078 * are already allocated on behalf of the file. Private mappings need
3079 * to reserve the full area even if read-only as mprotect() may be
3080 * called to make the mapping read-write. Assume !vma is a shm mapping
3082 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3083 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3085 struct resv_map
*resv_map
= resv_map_alloc();
3091 set_vma_resv_map(vma
, resv_map
);
3092 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3100 /* There must be enough pages in the subpool for the mapping */
3101 if (hugepage_subpool_get_pages(spool
, chg
)) {
3107 * Check enough hugepages are available for the reservation.
3108 * Hand the pages back to the subpool if there are not
3110 ret
= hugetlb_acct_memory(h
, chg
);
3112 hugepage_subpool_put_pages(spool
, chg
);
3117 * Account for the reservations made. Shared mappings record regions
3118 * that have reservations as they are shared by multiple VMAs.
3119 * When the last VMA disappears, the region map says how much
3120 * the reservation was and the page cache tells how much of
3121 * the reservation was consumed. Private mappings are per-VMA and
3122 * only the consumed reservations are tracked. When the VMA
3123 * disappears, the original reservation is the VMA size and the
3124 * consumed reservations are stored in the map. Hence, nothing
3125 * else has to be done for private mappings here
3127 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3128 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3136 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3138 struct hstate
*h
= hstate_inode(inode
);
3139 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3140 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3142 spin_lock(&inode
->i_lock
);
3143 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3144 spin_unlock(&inode
->i_lock
);
3146 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3147 hugetlb_acct_memory(h
, -(chg
- freed
));
3150 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3151 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3152 struct vm_area_struct
*vma
,
3153 unsigned long addr
, pgoff_t idx
)
3155 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3157 unsigned long sbase
= saddr
& PUD_MASK
;
3158 unsigned long s_end
= sbase
+ PUD_SIZE
;
3160 /* Allow segments to share if only one is marked locked */
3161 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3162 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3165 * match the virtual addresses, permission and the alignment of the
3168 if (pmd_index(addr
) != pmd_index(saddr
) ||
3169 vm_flags
!= svm_flags
||
3170 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3176 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3178 unsigned long base
= addr
& PUD_MASK
;
3179 unsigned long end
= base
+ PUD_SIZE
;
3182 * check on proper vm_flags and page table alignment
3184 if (vma
->vm_flags
& VM_MAYSHARE
&&
3185 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3191 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3192 * and returns the corresponding pte. While this is not necessary for the
3193 * !shared pmd case because we can allocate the pmd later as well, it makes the
3194 * code much cleaner. pmd allocation is essential for the shared case because
3195 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3196 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3197 * bad pmd for sharing.
3199 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3201 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3202 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3203 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3205 struct vm_area_struct
*svma
;
3206 unsigned long saddr
;
3210 if (!vma_shareable(vma
, addr
))
3211 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3213 mutex_lock(&mapping
->i_mmap_mutex
);
3214 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3218 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3220 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3222 get_page(virt_to_page(spte
));
3231 spin_lock(&mm
->page_table_lock
);
3233 pud_populate(mm
, pud
,
3234 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3236 put_page(virt_to_page(spte
));
3237 spin_unlock(&mm
->page_table_lock
);
3239 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3240 mutex_unlock(&mapping
->i_mmap_mutex
);
3245 * unmap huge page backed by shared pte.
3247 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3248 * indicated by page_count > 1, unmap is achieved by clearing pud and
3249 * decrementing the ref count. If count == 1, the pte page is not shared.
3251 * called with vma->vm_mm->page_table_lock held.
3253 * returns: 1 successfully unmapped a shared pte page
3254 * 0 the underlying pte page is not shared, or it is the last user
3256 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3258 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3259 pud_t
*pud
= pud_offset(pgd
, *addr
);
3261 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3262 if (page_count(virt_to_page(ptep
)) == 1)
3266 put_page(virt_to_page(ptep
));
3267 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3270 #define want_pmd_share() (1)
3271 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3272 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3276 #define want_pmd_share() (0)
3277 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3279 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3280 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3281 unsigned long addr
, unsigned long sz
)
3287 pgd
= pgd_offset(mm
, addr
);
3288 pud
= pud_alloc(mm
, pgd
, addr
);
3290 if (sz
== PUD_SIZE
) {
3293 BUG_ON(sz
!= PMD_SIZE
);
3294 if (want_pmd_share() && pud_none(*pud
))
3295 pte
= huge_pmd_share(mm
, addr
, pud
);
3297 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3300 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3305 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3311 pgd
= pgd_offset(mm
, addr
);
3312 if (pgd_present(*pgd
)) {
3313 pud
= pud_offset(pgd
, addr
);
3314 if (pud_present(*pud
)) {
3316 return (pte_t
*)pud
;
3317 pmd
= pmd_offset(pud
, addr
);
3320 return (pte_t
*) pmd
;
3324 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3325 pmd_t
*pmd
, int write
)
3329 page
= pte_page(*(pte_t
*)pmd
);
3331 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3336 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3337 pud_t
*pud
, int write
)
3341 page
= pte_page(*(pte_t
*)pud
);
3343 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3347 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3349 /* Can be overriden by architectures */
3350 __attribute__((weak
)) struct page
*
3351 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3352 pud_t
*pud
, int write
)
3358 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3360 #ifdef CONFIG_MEMORY_FAILURE
3362 /* Should be called in hugetlb_lock */
3363 static int is_hugepage_on_freelist(struct page
*hpage
)
3367 struct hstate
*h
= page_hstate(hpage
);
3368 int nid
= page_to_nid(hpage
);
3370 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3377 * This function is called from memory failure code.
3378 * Assume the caller holds page lock of the head page.
3380 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3382 struct hstate
*h
= page_hstate(hpage
);
3383 int nid
= page_to_nid(hpage
);
3386 spin_lock(&hugetlb_lock
);
3387 if (is_hugepage_on_freelist(hpage
)) {
3389 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3390 * but dangling hpage->lru can trigger list-debug warnings
3391 * (this happens when we call unpoison_memory() on it),
3392 * so let it point to itself with list_del_init().
3394 list_del_init(&hpage
->lru
);
3395 set_page_refcounted(hpage
);
3396 h
->free_huge_pages
--;
3397 h
->free_huge_pages_node
[nid
]--;
3400 spin_unlock(&hugetlb_lock
);