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>
24 #include <linux/page-isolation.h>
27 #include <asm/pgtable.h>
31 #include <linux/hugetlb.h>
32 #include <linux/hugetlb_cgroup.h>
33 #include <linux/node.h>
36 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
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, hugepage_activelist, nr_huge_pages,
52 * free_huge_pages, and surplus_huge_pages.
54 DEFINE_SPINLOCK(hugetlb_lock
);
56 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
58 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
60 spin_unlock(&spool
->lock
);
62 /* If no pages are used, and no other handles to the subpool
63 * remain, free the subpool the subpool remain */
68 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
70 struct hugepage_subpool
*spool
;
72 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
76 spin_lock_init(&spool
->lock
);
78 spool
->max_hpages
= nr_blocks
;
79 spool
->used_hpages
= 0;
84 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
86 spin_lock(&spool
->lock
);
87 BUG_ON(!spool
->count
);
89 unlock_or_release_subpool(spool
);
92 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
100 spin_lock(&spool
->lock
);
101 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
102 spool
->used_hpages
+= delta
;
106 spin_unlock(&spool
->lock
);
111 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
117 spin_lock(&spool
->lock
);
118 spool
->used_hpages
-= delta
;
119 /* If hugetlbfs_put_super couldn't free spool due to
120 * an outstanding quota reference, free it now. */
121 unlock_or_release_subpool(spool
);
124 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
126 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
129 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
131 return subpool_inode(file_inode(vma
->vm_file
));
135 * Region tracking -- allows tracking of reservations and instantiated pages
136 * across the pages in a mapping.
138 * The region data structures are protected by a combination of the mmap_sem
139 * and the hugetlb_instantiation_mutex. To access or modify a region the caller
140 * must either hold the mmap_sem for write, or the mmap_sem for read and
141 * the hugetlb_instantiation_mutex:
143 * down_write(&mm->mmap_sem);
145 * down_read(&mm->mmap_sem);
146 * mutex_lock(&hugetlb_instantiation_mutex);
149 struct list_head link
;
154 static long region_add(struct list_head
*head
, long f
, long t
)
156 struct file_region
*rg
, *nrg
, *trg
;
158 /* Locate the region we are either in or before. */
159 list_for_each_entry(rg
, head
, link
)
163 /* Round our left edge to the current segment if it encloses us. */
167 /* Check for and consume any regions we now overlap with. */
169 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
170 if (&rg
->link
== head
)
175 /* If this area reaches higher then extend our area to
176 * include it completely. If this is not the first area
177 * which we intend to reuse, free it. */
190 static long region_chg(struct list_head
*head
, long f
, long t
)
192 struct file_region
*rg
, *nrg
;
195 /* Locate the region we are before or in. */
196 list_for_each_entry(rg
, head
, link
)
200 /* If we are below the current region then a new region is required.
201 * Subtle, allocate a new region at the position but make it zero
202 * size such that we can guarantee to record the reservation. */
203 if (&rg
->link
== head
|| t
< rg
->from
) {
204 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
209 INIT_LIST_HEAD(&nrg
->link
);
210 list_add(&nrg
->link
, rg
->link
.prev
);
215 /* Round our left edge to the current segment if it encloses us. */
220 /* Check for and consume any regions we now overlap with. */
221 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
222 if (&rg
->link
== head
)
227 /* We overlap with this area, if it extends further than
228 * us then we must extend ourselves. Account for its
229 * existing reservation. */
234 chg
-= rg
->to
- rg
->from
;
239 static long region_truncate(struct list_head
*head
, long end
)
241 struct file_region
*rg
, *trg
;
244 /* Locate the region we are either in or before. */
245 list_for_each_entry(rg
, head
, link
)
248 if (&rg
->link
== head
)
251 /* If we are in the middle of a region then adjust it. */
252 if (end
> rg
->from
) {
255 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
258 /* Drop any remaining regions. */
259 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
260 if (&rg
->link
== head
)
262 chg
+= rg
->to
- rg
->from
;
269 static long region_count(struct list_head
*head
, long f
, long t
)
271 struct file_region
*rg
;
274 /* Locate each segment we overlap with, and count that overlap. */
275 list_for_each_entry(rg
, head
, link
) {
284 seg_from
= max(rg
->from
, f
);
285 seg_to
= min(rg
->to
, t
);
287 chg
+= seg_to
- seg_from
;
294 * Convert the address within this vma to the page offset within
295 * the mapping, in pagecache page units; huge pages here.
297 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
298 struct vm_area_struct
*vma
, unsigned long address
)
300 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
301 (vma
->vm_pgoff
>> huge_page_order(h
));
304 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
305 unsigned long address
)
307 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
311 * Return the size of the pages allocated when backing a VMA. In the majority
312 * cases this will be same size as used by the page table entries.
314 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
316 struct hstate
*hstate
;
318 if (!is_vm_hugetlb_page(vma
))
321 hstate
= hstate_vma(vma
);
323 return 1UL << huge_page_shift(hstate
);
325 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
328 * Return the page size being used by the MMU to back a VMA. In the majority
329 * of cases, the page size used by the kernel matches the MMU size. On
330 * architectures where it differs, an architecture-specific version of this
331 * function is required.
333 #ifndef vma_mmu_pagesize
334 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
336 return vma_kernel_pagesize(vma
);
341 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
342 * bits of the reservation map pointer, which are always clear due to
345 #define HPAGE_RESV_OWNER (1UL << 0)
346 #define HPAGE_RESV_UNMAPPED (1UL << 1)
347 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
350 * These helpers are used to track how many pages are reserved for
351 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
352 * is guaranteed to have their future faults succeed.
354 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
355 * the reserve counters are updated with the hugetlb_lock held. It is safe
356 * to reset the VMA at fork() time as it is not in use yet and there is no
357 * chance of the global counters getting corrupted as a result of the values.
359 * The private mapping reservation is represented in a subtly different
360 * manner to a shared mapping. A shared mapping has a region map associated
361 * with the underlying file, this region map represents the backing file
362 * pages which have ever had a reservation assigned which this persists even
363 * after the page is instantiated. A private mapping has a region map
364 * associated with the original mmap which is attached to all VMAs which
365 * reference it, this region map represents those offsets which have consumed
366 * reservation ie. where pages have been instantiated.
368 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
370 return (unsigned long)vma
->vm_private_data
;
373 static void set_vma_private_data(struct vm_area_struct
*vma
,
376 vma
->vm_private_data
= (void *)value
;
381 struct list_head regions
;
384 static struct resv_map
*resv_map_alloc(void)
386 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
390 kref_init(&resv_map
->refs
);
391 INIT_LIST_HEAD(&resv_map
->regions
);
396 static void resv_map_release(struct kref
*ref
)
398 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
400 /* Clear out any active regions before we release the map. */
401 region_truncate(&resv_map
->regions
, 0);
405 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
407 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
408 if (!(vma
->vm_flags
& VM_MAYSHARE
))
409 return (struct resv_map
*)(get_vma_private_data(vma
) &
414 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
416 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
417 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
419 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
420 HPAGE_RESV_MASK
) | (unsigned long)map
);
423 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
425 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
426 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
428 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
431 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
433 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
435 return (get_vma_private_data(vma
) & flag
) != 0;
438 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
439 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
441 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
442 if (!(vma
->vm_flags
& VM_MAYSHARE
))
443 vma
->vm_private_data
= (void *)0;
446 /* Returns true if the VMA has associated reserve pages */
447 static int vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
449 if (vma
->vm_flags
& VM_NORESERVE
) {
451 * This address is already reserved by other process(chg == 0),
452 * so, we should decrement reserved count. Without decrementing,
453 * reserve count remains after releasing inode, because this
454 * allocated page will go into page cache and is regarded as
455 * coming from reserved pool in releasing step. Currently, we
456 * don't have any other solution to deal with this situation
457 * properly, so add work-around here.
459 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
465 /* Shared mappings always use reserves */
466 if (vma
->vm_flags
& VM_MAYSHARE
)
470 * Only the process that called mmap() has reserves for
473 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
479 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
481 int nid
= page_to_nid(page
);
482 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
483 h
->free_huge_pages
++;
484 h
->free_huge_pages_node
[nid
]++;
487 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
491 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
492 if (!is_migrate_isolate_page(page
))
495 * if 'non-isolated free hugepage' not found on the list,
496 * the allocation fails.
498 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
500 list_move(&page
->lru
, &h
->hugepage_activelist
);
501 set_page_refcounted(page
);
502 h
->free_huge_pages
--;
503 h
->free_huge_pages_node
[nid
]--;
507 /* Movability of hugepages depends on migration support. */
508 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
510 if (hugepages_treat_as_movable
|| hugepage_migration_support(h
))
511 return GFP_HIGHUSER_MOVABLE
;
516 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
517 struct vm_area_struct
*vma
,
518 unsigned long address
, int avoid_reserve
,
521 struct page
*page
= NULL
;
522 struct mempolicy
*mpol
;
523 nodemask_t
*nodemask
;
524 struct zonelist
*zonelist
;
527 unsigned int cpuset_mems_cookie
;
530 * A child process with MAP_PRIVATE mappings created by their parent
531 * have no page reserves. This check ensures that reservations are
532 * not "stolen". The child may still get SIGKILLed
534 if (!vma_has_reserves(vma
, chg
) &&
535 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
538 /* If reserves cannot be used, ensure enough pages are in the pool */
539 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
543 cpuset_mems_cookie
= get_mems_allowed();
544 zonelist
= huge_zonelist(vma
, address
,
545 htlb_alloc_mask(h
), &mpol
, &nodemask
);
547 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
548 MAX_NR_ZONES
- 1, nodemask
) {
549 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask(h
))) {
550 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
554 if (!vma_has_reserves(vma
, chg
))
557 SetPagePrivate(page
);
558 h
->resv_huge_pages
--;
565 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
573 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
577 VM_BUG_ON(h
->order
>= MAX_ORDER
);
580 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
581 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
582 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
583 1 << PG_referenced
| 1 << PG_dirty
|
584 1 << PG_active
| 1 << PG_reserved
|
585 1 << PG_private
| 1 << PG_writeback
);
587 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
588 set_compound_page_dtor(page
, NULL
);
589 set_page_refcounted(page
);
590 arch_release_hugepage(page
);
591 __free_pages(page
, huge_page_order(h
));
594 struct hstate
*size_to_hstate(unsigned long size
)
599 if (huge_page_size(h
) == size
)
605 static void free_huge_page(struct page
*page
)
608 * Can't pass hstate in here because it is called from the
609 * compound page destructor.
611 struct hstate
*h
= page_hstate(page
);
612 int nid
= page_to_nid(page
);
613 struct hugepage_subpool
*spool
=
614 (struct hugepage_subpool
*)page_private(page
);
615 bool restore_reserve
;
617 set_page_private(page
, 0);
618 page
->mapping
= NULL
;
619 BUG_ON(page_count(page
));
620 BUG_ON(page_mapcount(page
));
621 restore_reserve
= PagePrivate(page
);
622 ClearPagePrivate(page
);
624 spin_lock(&hugetlb_lock
);
625 hugetlb_cgroup_uncharge_page(hstate_index(h
),
626 pages_per_huge_page(h
), page
);
628 h
->resv_huge_pages
++;
630 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
631 /* remove the page from active list */
632 list_del(&page
->lru
);
633 update_and_free_page(h
, page
);
634 h
->surplus_huge_pages
--;
635 h
->surplus_huge_pages_node
[nid
]--;
637 arch_clear_hugepage_flags(page
);
638 enqueue_huge_page(h
, page
);
640 spin_unlock(&hugetlb_lock
);
641 hugepage_subpool_put_pages(spool
, 1);
644 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
646 INIT_LIST_HEAD(&page
->lru
);
647 set_compound_page_dtor(page
, free_huge_page
);
648 spin_lock(&hugetlb_lock
);
649 set_hugetlb_cgroup(page
, NULL
);
651 h
->nr_huge_pages_node
[nid
]++;
652 spin_unlock(&hugetlb_lock
);
653 put_page(page
); /* free it into the hugepage allocator */
656 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
659 int nr_pages
= 1 << order
;
660 struct page
*p
= page
+ 1;
662 /* we rely on prep_new_huge_page to set the destructor */
663 set_compound_order(page
, order
);
665 __ClearPageReserved(page
);
666 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
669 * For gigantic hugepages allocated through bootmem at
670 * boot, it's safer to be consistent with the not-gigantic
671 * hugepages and clear the PG_reserved bit from all tail pages
672 * too. Otherwse drivers using get_user_pages() to access tail
673 * pages may get the reference counting wrong if they see
674 * PG_reserved set on a tail page (despite the head page not
675 * having PG_reserved set). Enforcing this consistency between
676 * head and tail pages allows drivers to optimize away a check
677 * on the head page when they need know if put_page() is needed
678 * after get_user_pages().
680 __ClearPageReserved(p
);
681 set_page_count(p
, 0);
682 p
->first_page
= page
;
687 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
688 * transparent huge pages. See the PageTransHuge() documentation for more
691 int PageHuge(struct page
*page
)
693 compound_page_dtor
*dtor
;
695 if (!PageCompound(page
))
698 page
= compound_head(page
);
699 dtor
= get_compound_page_dtor(page
);
701 return dtor
== free_huge_page
;
703 EXPORT_SYMBOL_GPL(PageHuge
);
706 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
707 * normal or transparent huge pages.
709 int PageHeadHuge(struct page
*page_head
)
711 compound_page_dtor
*dtor
;
713 if (!PageHead(page_head
))
716 dtor
= get_compound_page_dtor(page_head
);
718 return dtor
== free_huge_page
;
720 EXPORT_SYMBOL_GPL(PageHeadHuge
);
722 pgoff_t
__basepage_index(struct page
*page
)
724 struct page
*page_head
= compound_head(page
);
725 pgoff_t index
= page_index(page_head
);
726 unsigned long compound_idx
;
728 if (!PageHuge(page_head
))
729 return page_index(page
);
731 if (compound_order(page_head
) >= MAX_ORDER
)
732 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
734 compound_idx
= page
- page_head
;
736 return (index
<< compound_order(page_head
)) + compound_idx
;
739 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
743 if (h
->order
>= MAX_ORDER
)
746 page
= alloc_pages_exact_node(nid
,
747 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
748 __GFP_REPEAT
|__GFP_NOWARN
,
751 if (arch_prepare_hugepage(page
)) {
752 __free_pages(page
, huge_page_order(h
));
755 prep_new_huge_page(h
, page
, nid
);
762 * common helper functions for hstate_next_node_to_{alloc|free}.
763 * We may have allocated or freed a huge page based on a different
764 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
765 * be outside of *nodes_allowed. Ensure that we use an allowed
766 * node for alloc or free.
768 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
770 nid
= next_node(nid
, *nodes_allowed
);
771 if (nid
== MAX_NUMNODES
)
772 nid
= first_node(*nodes_allowed
);
773 VM_BUG_ON(nid
>= MAX_NUMNODES
);
778 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
780 if (!node_isset(nid
, *nodes_allowed
))
781 nid
= next_node_allowed(nid
, nodes_allowed
);
786 * returns the previously saved node ["this node"] from which to
787 * allocate a persistent huge page for the pool and advance the
788 * next node from which to allocate, handling wrap at end of node
791 static int hstate_next_node_to_alloc(struct hstate
*h
,
792 nodemask_t
*nodes_allowed
)
796 VM_BUG_ON(!nodes_allowed
);
798 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
799 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
805 * helper for free_pool_huge_page() - return the previously saved
806 * node ["this node"] from which to free a huge page. Advance the
807 * next node id whether or not we find a free huge page to free so
808 * that the next attempt to free addresses the next node.
810 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
814 VM_BUG_ON(!nodes_allowed
);
816 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
817 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
822 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
823 for (nr_nodes = nodes_weight(*mask); \
825 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
828 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
829 for (nr_nodes = nodes_weight(*mask); \
831 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
834 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
840 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
841 page
= alloc_fresh_huge_page_node(h
, node
);
849 count_vm_event(HTLB_BUDDY_PGALLOC
);
851 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
857 * Free huge page from pool from next node to free.
858 * Attempt to keep persistent huge pages more or less
859 * balanced over allowed nodes.
860 * Called with hugetlb_lock locked.
862 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
868 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
870 * If we're returning unused surplus pages, only examine
871 * nodes with surplus pages.
873 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
874 !list_empty(&h
->hugepage_freelists
[node
])) {
876 list_entry(h
->hugepage_freelists
[node
].next
,
878 list_del(&page
->lru
);
879 h
->free_huge_pages
--;
880 h
->free_huge_pages_node
[node
]--;
882 h
->surplus_huge_pages
--;
883 h
->surplus_huge_pages_node
[node
]--;
885 update_and_free_page(h
, page
);
895 * Dissolve a given free hugepage into free buddy pages. This function does
896 * nothing for in-use (including surplus) hugepages.
898 static void dissolve_free_huge_page(struct page
*page
)
900 spin_lock(&hugetlb_lock
);
901 if (PageHuge(page
) && !page_count(page
)) {
902 struct hstate
*h
= page_hstate(page
);
903 int nid
= page_to_nid(page
);
904 list_del(&page
->lru
);
905 h
->free_huge_pages
--;
906 h
->free_huge_pages_node
[nid
]--;
907 update_and_free_page(h
, page
);
909 spin_unlock(&hugetlb_lock
);
913 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
914 * make specified memory blocks removable from the system.
915 * Note that start_pfn should aligned with (minimum) hugepage size.
917 void dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
919 unsigned int order
= 8 * sizeof(void *);
923 /* Set scan step to minimum hugepage size */
925 if (order
> huge_page_order(h
))
926 order
= huge_page_order(h
);
927 VM_BUG_ON(!IS_ALIGNED(start_pfn
, 1 << order
));
928 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << order
)
929 dissolve_free_huge_page(pfn_to_page(pfn
));
932 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
937 if (h
->order
>= MAX_ORDER
)
941 * Assume we will successfully allocate the surplus page to
942 * prevent racing processes from causing the surplus to exceed
945 * This however introduces a different race, where a process B
946 * tries to grow the static hugepage pool while alloc_pages() is
947 * called by process A. B will only examine the per-node
948 * counters in determining if surplus huge pages can be
949 * converted to normal huge pages in adjust_pool_surplus(). A
950 * won't be able to increment the per-node counter, until the
951 * lock is dropped by B, but B doesn't drop hugetlb_lock until
952 * no more huge pages can be converted from surplus to normal
953 * state (and doesn't try to convert again). Thus, we have a
954 * case where a surplus huge page exists, the pool is grown, and
955 * the surplus huge page still exists after, even though it
956 * should just have been converted to a normal huge page. This
957 * does not leak memory, though, as the hugepage will be freed
958 * once it is out of use. It also does not allow the counters to
959 * go out of whack in adjust_pool_surplus() as we don't modify
960 * the node values until we've gotten the hugepage and only the
961 * per-node value is checked there.
963 spin_lock(&hugetlb_lock
);
964 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
965 spin_unlock(&hugetlb_lock
);
969 h
->surplus_huge_pages
++;
971 spin_unlock(&hugetlb_lock
);
973 if (nid
== NUMA_NO_NODE
)
974 page
= alloc_pages(htlb_alloc_mask(h
)|__GFP_COMP
|
975 __GFP_REPEAT
|__GFP_NOWARN
,
978 page
= alloc_pages_exact_node(nid
,
979 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
980 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
982 if (page
&& arch_prepare_hugepage(page
)) {
983 __free_pages(page
, huge_page_order(h
));
987 spin_lock(&hugetlb_lock
);
989 INIT_LIST_HEAD(&page
->lru
);
990 r_nid
= page_to_nid(page
);
991 set_compound_page_dtor(page
, free_huge_page
);
992 set_hugetlb_cgroup(page
, NULL
);
994 * We incremented the global counters already
996 h
->nr_huge_pages_node
[r_nid
]++;
997 h
->surplus_huge_pages_node
[r_nid
]++;
998 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1001 h
->surplus_huge_pages
--;
1002 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1004 spin_unlock(&hugetlb_lock
);
1010 * This allocation function is useful in the context where vma is irrelevant.
1011 * E.g. soft-offlining uses this function because it only cares physical
1012 * address of error page.
1014 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1016 struct page
*page
= NULL
;
1018 spin_lock(&hugetlb_lock
);
1019 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1020 page
= dequeue_huge_page_node(h
, nid
);
1021 spin_unlock(&hugetlb_lock
);
1024 page
= alloc_buddy_huge_page(h
, nid
);
1030 * Increase the hugetlb pool such that it can accommodate a reservation
1033 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1035 struct list_head surplus_list
;
1036 struct page
*page
, *tmp
;
1038 int needed
, allocated
;
1039 bool alloc_ok
= true;
1041 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1043 h
->resv_huge_pages
+= delta
;
1048 INIT_LIST_HEAD(&surplus_list
);
1052 spin_unlock(&hugetlb_lock
);
1053 for (i
= 0; i
< needed
; i
++) {
1054 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1059 list_add(&page
->lru
, &surplus_list
);
1064 * After retaking hugetlb_lock, we need to recalculate 'needed'
1065 * because either resv_huge_pages or free_huge_pages may have changed.
1067 spin_lock(&hugetlb_lock
);
1068 needed
= (h
->resv_huge_pages
+ delta
) -
1069 (h
->free_huge_pages
+ allocated
);
1074 * We were not able to allocate enough pages to
1075 * satisfy the entire reservation so we free what
1076 * we've allocated so far.
1081 * The surplus_list now contains _at_least_ the number of extra pages
1082 * needed to accommodate the reservation. Add the appropriate number
1083 * of pages to the hugetlb pool and free the extras back to the buddy
1084 * allocator. Commit the entire reservation here to prevent another
1085 * process from stealing the pages as they are added to the pool but
1086 * before they are reserved.
1088 needed
+= allocated
;
1089 h
->resv_huge_pages
+= delta
;
1092 /* Free the needed pages to the hugetlb pool */
1093 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1097 * This page is now managed by the hugetlb allocator and has
1098 * no users -- drop the buddy allocator's reference.
1100 put_page_testzero(page
);
1101 VM_BUG_ON(page_count(page
));
1102 enqueue_huge_page(h
, page
);
1105 spin_unlock(&hugetlb_lock
);
1107 /* Free unnecessary surplus pages to the buddy allocator */
1108 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1110 spin_lock(&hugetlb_lock
);
1116 * When releasing a hugetlb pool reservation, any surplus pages that were
1117 * allocated to satisfy the reservation must be explicitly freed if they were
1119 * Called with hugetlb_lock held.
1121 static void return_unused_surplus_pages(struct hstate
*h
,
1122 unsigned long unused_resv_pages
)
1124 unsigned long nr_pages
;
1126 /* Uncommit the reservation */
1127 h
->resv_huge_pages
-= unused_resv_pages
;
1129 /* Cannot return gigantic pages currently */
1130 if (h
->order
>= MAX_ORDER
)
1133 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1136 * We want to release as many surplus pages as possible, spread
1137 * evenly across all nodes with memory. Iterate across these nodes
1138 * until we can no longer free unreserved surplus pages. This occurs
1139 * when the nodes with surplus pages have no free pages.
1140 * free_pool_huge_page() will balance the the freed pages across the
1141 * on-line nodes with memory and will handle the hstate accounting.
1143 while (nr_pages
--) {
1144 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1150 * Determine if the huge page at addr within the vma has an associated
1151 * reservation. Where it does not we will need to logically increase
1152 * reservation and actually increase subpool usage before an allocation
1153 * can occur. Where any new reservation would be required the
1154 * reservation change is prepared, but not committed. Once the page
1155 * has been allocated from the subpool and instantiated the change should
1156 * be committed via vma_commit_reservation. No action is required on
1159 static long vma_needs_reservation(struct hstate
*h
,
1160 struct vm_area_struct
*vma
, unsigned long addr
)
1162 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1163 struct inode
*inode
= mapping
->host
;
1165 if (vma
->vm_flags
& VM_MAYSHARE
) {
1166 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1167 return region_chg(&inode
->i_mapping
->private_list
,
1170 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1175 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1176 struct resv_map
*resv
= vma_resv_map(vma
);
1178 err
= region_chg(&resv
->regions
, idx
, idx
+ 1);
1184 static void vma_commit_reservation(struct hstate
*h
,
1185 struct vm_area_struct
*vma
, unsigned long addr
)
1187 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1188 struct inode
*inode
= mapping
->host
;
1190 if (vma
->vm_flags
& VM_MAYSHARE
) {
1191 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1192 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1194 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1195 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1196 struct resv_map
*resv
= vma_resv_map(vma
);
1198 /* Mark this page used in the map. */
1199 region_add(&resv
->regions
, idx
, idx
+ 1);
1203 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1204 unsigned long addr
, int avoid_reserve
)
1206 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1207 struct hstate
*h
= hstate_vma(vma
);
1211 struct hugetlb_cgroup
*h_cg
;
1213 idx
= hstate_index(h
);
1215 * Processes that did not create the mapping will have no
1216 * reserves and will not have accounted against subpool
1217 * limit. Check that the subpool limit can be made before
1218 * satisfying the allocation MAP_NORESERVE mappings may also
1219 * need pages and subpool limit allocated allocated if no reserve
1222 chg
= vma_needs_reservation(h
, vma
, addr
);
1224 return ERR_PTR(-ENOMEM
);
1225 if (chg
|| avoid_reserve
)
1226 if (hugepage_subpool_get_pages(spool
, 1))
1227 return ERR_PTR(-ENOSPC
);
1229 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1231 if (chg
|| avoid_reserve
)
1232 hugepage_subpool_put_pages(spool
, 1);
1233 return ERR_PTR(-ENOSPC
);
1235 spin_lock(&hugetlb_lock
);
1236 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, chg
);
1238 spin_unlock(&hugetlb_lock
);
1239 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1241 hugetlb_cgroup_uncharge_cgroup(idx
,
1242 pages_per_huge_page(h
),
1244 if (chg
|| avoid_reserve
)
1245 hugepage_subpool_put_pages(spool
, 1);
1246 return ERR_PTR(-ENOSPC
);
1248 spin_lock(&hugetlb_lock
);
1249 list_move(&page
->lru
, &h
->hugepage_activelist
);
1252 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1253 spin_unlock(&hugetlb_lock
);
1255 set_page_private(page
, (unsigned long)spool
);
1257 vma_commit_reservation(h
, vma
, addr
);
1262 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1263 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1264 * where no ERR_VALUE is expected to be returned.
1266 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
1267 unsigned long addr
, int avoid_reserve
)
1269 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
1275 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1277 struct huge_bootmem_page
*m
;
1280 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1283 addr
= __alloc_bootmem_node_nopanic(NODE_DATA(node
),
1284 huge_page_size(h
), huge_page_size(h
), 0);
1288 * Use the beginning of the huge page to store the
1289 * huge_bootmem_page struct (until gather_bootmem
1290 * puts them into the mem_map).
1299 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1300 /* Put them into a private list first because mem_map is not up yet */
1301 list_add(&m
->list
, &huge_boot_pages
);
1306 static void prep_compound_huge_page(struct page
*page
, int order
)
1308 if (unlikely(order
> (MAX_ORDER
- 1)))
1309 prep_compound_gigantic_page(page
, order
);
1311 prep_compound_page(page
, order
);
1314 /* Put bootmem huge pages into the standard lists after mem_map is up */
1315 static void __init
gather_bootmem_prealloc(void)
1317 struct huge_bootmem_page
*m
;
1319 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1320 struct hstate
*h
= m
->hstate
;
1323 #ifdef CONFIG_HIGHMEM
1324 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1325 free_bootmem_late((unsigned long)m
,
1326 sizeof(struct huge_bootmem_page
));
1328 page
= virt_to_page(m
);
1330 WARN_ON(page_count(page
) != 1);
1331 prep_compound_huge_page(page
, h
->order
);
1332 WARN_ON(PageReserved(page
));
1333 prep_new_huge_page(h
, page
, page_to_nid(page
));
1335 * If we had gigantic hugepages allocated at boot time, we need
1336 * to restore the 'stolen' pages to totalram_pages in order to
1337 * fix confusing memory reports from free(1) and another
1338 * side-effects, like CommitLimit going negative.
1340 if (h
->order
> (MAX_ORDER
- 1))
1341 adjust_managed_page_count(page
, 1 << h
->order
);
1345 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1349 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1350 if (h
->order
>= MAX_ORDER
) {
1351 if (!alloc_bootmem_huge_page(h
))
1353 } else if (!alloc_fresh_huge_page(h
,
1354 &node_states
[N_MEMORY
]))
1357 h
->max_huge_pages
= i
;
1360 static void __init
hugetlb_init_hstates(void)
1364 for_each_hstate(h
) {
1365 /* oversize hugepages were init'ed in early boot */
1366 if (h
->order
< MAX_ORDER
)
1367 hugetlb_hstate_alloc_pages(h
);
1371 static char * __init
memfmt(char *buf
, unsigned long n
)
1373 if (n
>= (1UL << 30))
1374 sprintf(buf
, "%lu GB", n
>> 30);
1375 else if (n
>= (1UL << 20))
1376 sprintf(buf
, "%lu MB", n
>> 20);
1378 sprintf(buf
, "%lu KB", n
>> 10);
1382 static void __init
report_hugepages(void)
1386 for_each_hstate(h
) {
1388 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1389 memfmt(buf
, huge_page_size(h
)),
1390 h
->free_huge_pages
);
1394 #ifdef CONFIG_HIGHMEM
1395 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1396 nodemask_t
*nodes_allowed
)
1400 if (h
->order
>= MAX_ORDER
)
1403 for_each_node_mask(i
, *nodes_allowed
) {
1404 struct page
*page
, *next
;
1405 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1406 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1407 if (count
>= h
->nr_huge_pages
)
1409 if (PageHighMem(page
))
1411 list_del(&page
->lru
);
1412 update_and_free_page(h
, page
);
1413 h
->free_huge_pages
--;
1414 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1419 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1420 nodemask_t
*nodes_allowed
)
1426 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1427 * balanced by operating on them in a round-robin fashion.
1428 * Returns 1 if an adjustment was made.
1430 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1435 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1438 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1439 if (h
->surplus_huge_pages_node
[node
])
1443 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1444 if (h
->surplus_huge_pages_node
[node
] <
1445 h
->nr_huge_pages_node
[node
])
1452 h
->surplus_huge_pages
+= delta
;
1453 h
->surplus_huge_pages_node
[node
] += delta
;
1457 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1458 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1459 nodemask_t
*nodes_allowed
)
1461 unsigned long min_count
, ret
;
1463 if (h
->order
>= MAX_ORDER
)
1464 return h
->max_huge_pages
;
1467 * Increase the pool size
1468 * First take pages out of surplus state. Then make up the
1469 * remaining difference by allocating fresh huge pages.
1471 * We might race with alloc_buddy_huge_page() here and be unable
1472 * to convert a surplus huge page to a normal huge page. That is
1473 * not critical, though, it just means the overall size of the
1474 * pool might be one hugepage larger than it needs to be, but
1475 * within all the constraints specified by the sysctls.
1477 spin_lock(&hugetlb_lock
);
1478 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1479 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1483 while (count
> persistent_huge_pages(h
)) {
1485 * If this allocation races such that we no longer need the
1486 * page, free_huge_page will handle it by freeing the page
1487 * and reducing the surplus.
1489 spin_unlock(&hugetlb_lock
);
1490 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1491 spin_lock(&hugetlb_lock
);
1495 /* Bail for signals. Probably ctrl-c from user */
1496 if (signal_pending(current
))
1501 * Decrease the pool size
1502 * First return free pages to the buddy allocator (being careful
1503 * to keep enough around to satisfy reservations). Then place
1504 * pages into surplus state as needed so the pool will shrink
1505 * to the desired size as pages become free.
1507 * By placing pages into the surplus state independent of the
1508 * overcommit value, we are allowing the surplus pool size to
1509 * exceed overcommit. There are few sane options here. Since
1510 * alloc_buddy_huge_page() is checking the global counter,
1511 * though, we'll note that we're not allowed to exceed surplus
1512 * and won't grow the pool anywhere else. Not until one of the
1513 * sysctls are changed, or the surplus pages go out of use.
1515 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1516 min_count
= max(count
, min_count
);
1517 try_to_free_low(h
, min_count
, nodes_allowed
);
1518 while (min_count
< persistent_huge_pages(h
)) {
1519 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1522 while (count
< persistent_huge_pages(h
)) {
1523 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1527 ret
= persistent_huge_pages(h
);
1528 spin_unlock(&hugetlb_lock
);
1532 #define HSTATE_ATTR_RO(_name) \
1533 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1535 #define HSTATE_ATTR(_name) \
1536 static struct kobj_attribute _name##_attr = \
1537 __ATTR(_name, 0644, _name##_show, _name##_store)
1539 static struct kobject
*hugepages_kobj
;
1540 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1542 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1544 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1548 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1549 if (hstate_kobjs
[i
] == kobj
) {
1551 *nidp
= NUMA_NO_NODE
;
1555 return kobj_to_node_hstate(kobj
, nidp
);
1558 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1559 struct kobj_attribute
*attr
, char *buf
)
1562 unsigned long nr_huge_pages
;
1565 h
= kobj_to_hstate(kobj
, &nid
);
1566 if (nid
== NUMA_NO_NODE
)
1567 nr_huge_pages
= h
->nr_huge_pages
;
1569 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1571 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1574 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1575 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1576 const char *buf
, size_t len
)
1580 unsigned long count
;
1582 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1584 err
= kstrtoul(buf
, 10, &count
);
1588 h
= kobj_to_hstate(kobj
, &nid
);
1589 if (h
->order
>= MAX_ORDER
) {
1594 if (nid
== NUMA_NO_NODE
) {
1596 * global hstate attribute
1598 if (!(obey_mempolicy
&&
1599 init_nodemask_of_mempolicy(nodes_allowed
))) {
1600 NODEMASK_FREE(nodes_allowed
);
1601 nodes_allowed
= &node_states
[N_MEMORY
];
1603 } else if (nodes_allowed
) {
1605 * per node hstate attribute: adjust count to global,
1606 * but restrict alloc/free to the specified node.
1608 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1609 init_nodemask_of_node(nodes_allowed
, nid
);
1611 nodes_allowed
= &node_states
[N_MEMORY
];
1613 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1615 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1616 NODEMASK_FREE(nodes_allowed
);
1620 NODEMASK_FREE(nodes_allowed
);
1624 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1625 struct kobj_attribute
*attr
, char *buf
)
1627 return nr_hugepages_show_common(kobj
, attr
, buf
);
1630 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1631 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1633 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1635 HSTATE_ATTR(nr_hugepages
);
1640 * hstate attribute for optionally mempolicy-based constraint on persistent
1641 * huge page alloc/free.
1643 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1644 struct kobj_attribute
*attr
, char *buf
)
1646 return nr_hugepages_show_common(kobj
, attr
, buf
);
1649 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1650 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1652 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1654 HSTATE_ATTR(nr_hugepages_mempolicy
);
1658 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1659 struct kobj_attribute
*attr
, char *buf
)
1661 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1662 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1665 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1666 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1669 unsigned long input
;
1670 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1672 if (h
->order
>= MAX_ORDER
)
1675 err
= kstrtoul(buf
, 10, &input
);
1679 spin_lock(&hugetlb_lock
);
1680 h
->nr_overcommit_huge_pages
= input
;
1681 spin_unlock(&hugetlb_lock
);
1685 HSTATE_ATTR(nr_overcommit_hugepages
);
1687 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1688 struct kobj_attribute
*attr
, char *buf
)
1691 unsigned long free_huge_pages
;
1694 h
= kobj_to_hstate(kobj
, &nid
);
1695 if (nid
== NUMA_NO_NODE
)
1696 free_huge_pages
= h
->free_huge_pages
;
1698 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1700 return sprintf(buf
, "%lu\n", free_huge_pages
);
1702 HSTATE_ATTR_RO(free_hugepages
);
1704 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1705 struct kobj_attribute
*attr
, char *buf
)
1707 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1708 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1710 HSTATE_ATTR_RO(resv_hugepages
);
1712 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1713 struct kobj_attribute
*attr
, char *buf
)
1716 unsigned long surplus_huge_pages
;
1719 h
= kobj_to_hstate(kobj
, &nid
);
1720 if (nid
== NUMA_NO_NODE
)
1721 surplus_huge_pages
= h
->surplus_huge_pages
;
1723 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1725 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1727 HSTATE_ATTR_RO(surplus_hugepages
);
1729 static struct attribute
*hstate_attrs
[] = {
1730 &nr_hugepages_attr
.attr
,
1731 &nr_overcommit_hugepages_attr
.attr
,
1732 &free_hugepages_attr
.attr
,
1733 &resv_hugepages_attr
.attr
,
1734 &surplus_hugepages_attr
.attr
,
1736 &nr_hugepages_mempolicy_attr
.attr
,
1741 static struct attribute_group hstate_attr_group
= {
1742 .attrs
= hstate_attrs
,
1745 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1746 struct kobject
**hstate_kobjs
,
1747 struct attribute_group
*hstate_attr_group
)
1750 int hi
= hstate_index(h
);
1752 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1753 if (!hstate_kobjs
[hi
])
1756 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1758 kobject_put(hstate_kobjs
[hi
]);
1763 static void __init
hugetlb_sysfs_init(void)
1768 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1769 if (!hugepages_kobj
)
1772 for_each_hstate(h
) {
1773 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1774 hstate_kobjs
, &hstate_attr_group
);
1776 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1783 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1784 * with node devices in node_devices[] using a parallel array. The array
1785 * index of a node device or _hstate == node id.
1786 * This is here to avoid any static dependency of the node device driver, in
1787 * the base kernel, on the hugetlb module.
1789 struct node_hstate
{
1790 struct kobject
*hugepages_kobj
;
1791 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1793 struct node_hstate node_hstates
[MAX_NUMNODES
];
1796 * A subset of global hstate attributes for node devices
1798 static struct attribute
*per_node_hstate_attrs
[] = {
1799 &nr_hugepages_attr
.attr
,
1800 &free_hugepages_attr
.attr
,
1801 &surplus_hugepages_attr
.attr
,
1805 static struct attribute_group per_node_hstate_attr_group
= {
1806 .attrs
= per_node_hstate_attrs
,
1810 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1811 * Returns node id via non-NULL nidp.
1813 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1817 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1818 struct node_hstate
*nhs
= &node_hstates
[nid
];
1820 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1821 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1833 * Unregister hstate attributes from a single node device.
1834 * No-op if no hstate attributes attached.
1836 static void hugetlb_unregister_node(struct node
*node
)
1839 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1841 if (!nhs
->hugepages_kobj
)
1842 return; /* no hstate attributes */
1844 for_each_hstate(h
) {
1845 int idx
= hstate_index(h
);
1846 if (nhs
->hstate_kobjs
[idx
]) {
1847 kobject_put(nhs
->hstate_kobjs
[idx
]);
1848 nhs
->hstate_kobjs
[idx
] = NULL
;
1852 kobject_put(nhs
->hugepages_kobj
);
1853 nhs
->hugepages_kobj
= NULL
;
1857 * hugetlb module exit: unregister hstate attributes from node devices
1860 static void hugetlb_unregister_all_nodes(void)
1865 * disable node device registrations.
1867 register_hugetlbfs_with_node(NULL
, NULL
);
1870 * remove hstate attributes from any nodes that have them.
1872 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1873 hugetlb_unregister_node(node_devices
[nid
]);
1877 * Register hstate attributes for a single node device.
1878 * No-op if attributes already registered.
1880 static void hugetlb_register_node(struct node
*node
)
1883 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1886 if (nhs
->hugepages_kobj
)
1887 return; /* already allocated */
1889 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1891 if (!nhs
->hugepages_kobj
)
1894 for_each_hstate(h
) {
1895 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1897 &per_node_hstate_attr_group
);
1899 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1900 h
->name
, node
->dev
.id
);
1901 hugetlb_unregister_node(node
);
1908 * hugetlb init time: register hstate attributes for all registered node
1909 * devices of nodes that have memory. All on-line nodes should have
1910 * registered their associated device by this time.
1912 static void hugetlb_register_all_nodes(void)
1916 for_each_node_state(nid
, N_MEMORY
) {
1917 struct node
*node
= node_devices
[nid
];
1918 if (node
->dev
.id
== nid
)
1919 hugetlb_register_node(node
);
1923 * Let the node device driver know we're here so it can
1924 * [un]register hstate attributes on node hotplug.
1926 register_hugetlbfs_with_node(hugetlb_register_node
,
1927 hugetlb_unregister_node
);
1929 #else /* !CONFIG_NUMA */
1931 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1939 static void hugetlb_unregister_all_nodes(void) { }
1941 static void hugetlb_register_all_nodes(void) { }
1945 static void __exit
hugetlb_exit(void)
1949 hugetlb_unregister_all_nodes();
1951 for_each_hstate(h
) {
1952 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1955 kobject_put(hugepages_kobj
);
1957 module_exit(hugetlb_exit
);
1959 static int __init
hugetlb_init(void)
1961 /* Some platform decide whether they support huge pages at boot
1962 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1963 * there is no such support
1965 if (HPAGE_SHIFT
== 0)
1968 if (!size_to_hstate(default_hstate_size
)) {
1969 default_hstate_size
= HPAGE_SIZE
;
1970 if (!size_to_hstate(default_hstate_size
))
1971 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1973 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1974 if (default_hstate_max_huge_pages
)
1975 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1977 hugetlb_init_hstates();
1978 gather_bootmem_prealloc();
1981 hugetlb_sysfs_init();
1982 hugetlb_register_all_nodes();
1983 hugetlb_cgroup_file_init();
1987 module_init(hugetlb_init
);
1989 /* Should be called on processing a hugepagesz=... option */
1990 void __init
hugetlb_add_hstate(unsigned order
)
1995 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1996 pr_warning("hugepagesz= specified twice, ignoring\n");
1999 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2001 h
= &hstates
[hugetlb_max_hstate
++];
2003 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2004 h
->nr_huge_pages
= 0;
2005 h
->free_huge_pages
= 0;
2006 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2007 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2008 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2009 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
2010 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
2011 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2012 huge_page_size(h
)/1024);
2017 static int __init
hugetlb_nrpages_setup(char *s
)
2020 static unsigned long *last_mhp
;
2023 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2024 * so this hugepages= parameter goes to the "default hstate".
2026 if (!hugetlb_max_hstate
)
2027 mhp
= &default_hstate_max_huge_pages
;
2029 mhp
= &parsed_hstate
->max_huge_pages
;
2031 if (mhp
== last_mhp
) {
2032 pr_warning("hugepages= specified twice without "
2033 "interleaving hugepagesz=, ignoring\n");
2037 if (sscanf(s
, "%lu", mhp
) <= 0)
2041 * Global state is always initialized later in hugetlb_init.
2042 * But we need to allocate >= MAX_ORDER hstates here early to still
2043 * use the bootmem allocator.
2045 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2046 hugetlb_hstate_alloc_pages(parsed_hstate
);
2052 __setup("hugepages=", hugetlb_nrpages_setup
);
2054 static int __init
hugetlb_default_setup(char *s
)
2056 default_hstate_size
= memparse(s
, &s
);
2059 __setup("default_hugepagesz=", hugetlb_default_setup
);
2061 static unsigned int cpuset_mems_nr(unsigned int *array
)
2064 unsigned int nr
= 0;
2066 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2072 #ifdef CONFIG_SYSCTL
2073 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2074 struct ctl_table
*table
, int write
,
2075 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2077 struct hstate
*h
= &default_hstate
;
2081 tmp
= h
->max_huge_pages
;
2083 if (write
&& h
->order
>= MAX_ORDER
)
2087 table
->maxlen
= sizeof(unsigned long);
2088 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2093 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2094 GFP_KERNEL
| __GFP_NORETRY
);
2095 if (!(obey_mempolicy
&&
2096 init_nodemask_of_mempolicy(nodes_allowed
))) {
2097 NODEMASK_FREE(nodes_allowed
);
2098 nodes_allowed
= &node_states
[N_MEMORY
];
2100 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2102 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2103 NODEMASK_FREE(nodes_allowed
);
2109 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2110 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2113 return hugetlb_sysctl_handler_common(false, table
, write
,
2114 buffer
, length
, ppos
);
2118 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2119 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2121 return hugetlb_sysctl_handler_common(true, table
, write
,
2122 buffer
, length
, ppos
);
2124 #endif /* CONFIG_NUMA */
2126 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2127 void __user
*buffer
,
2128 size_t *length
, loff_t
*ppos
)
2130 struct hstate
*h
= &default_hstate
;
2134 tmp
= h
->nr_overcommit_huge_pages
;
2136 if (write
&& h
->order
>= MAX_ORDER
)
2140 table
->maxlen
= sizeof(unsigned long);
2141 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2146 spin_lock(&hugetlb_lock
);
2147 h
->nr_overcommit_huge_pages
= tmp
;
2148 spin_unlock(&hugetlb_lock
);
2154 #endif /* CONFIG_SYSCTL */
2156 void hugetlb_report_meminfo(struct seq_file
*m
)
2158 struct hstate
*h
= &default_hstate
;
2160 "HugePages_Total: %5lu\n"
2161 "HugePages_Free: %5lu\n"
2162 "HugePages_Rsvd: %5lu\n"
2163 "HugePages_Surp: %5lu\n"
2164 "Hugepagesize: %8lu kB\n",
2168 h
->surplus_huge_pages
,
2169 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2172 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2174 struct hstate
*h
= &default_hstate
;
2176 "Node %d HugePages_Total: %5u\n"
2177 "Node %d HugePages_Free: %5u\n"
2178 "Node %d HugePages_Surp: %5u\n",
2179 nid
, h
->nr_huge_pages_node
[nid
],
2180 nid
, h
->free_huge_pages_node
[nid
],
2181 nid
, h
->surplus_huge_pages_node
[nid
]);
2184 void hugetlb_show_meminfo(void)
2189 for_each_node_state(nid
, N_MEMORY
)
2191 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2193 h
->nr_huge_pages_node
[nid
],
2194 h
->free_huge_pages_node
[nid
],
2195 h
->surplus_huge_pages_node
[nid
],
2196 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2199 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2200 unsigned long hugetlb_total_pages(void)
2203 unsigned long nr_total_pages
= 0;
2206 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2207 return nr_total_pages
;
2210 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2214 spin_lock(&hugetlb_lock
);
2216 * When cpuset is configured, it breaks the strict hugetlb page
2217 * reservation as the accounting is done on a global variable. Such
2218 * reservation is completely rubbish in the presence of cpuset because
2219 * the reservation is not checked against page availability for the
2220 * current cpuset. Application can still potentially OOM'ed by kernel
2221 * with lack of free htlb page in cpuset that the task is in.
2222 * Attempt to enforce strict accounting with cpuset is almost
2223 * impossible (or too ugly) because cpuset is too fluid that
2224 * task or memory node can be dynamically moved between cpusets.
2226 * The change of semantics for shared hugetlb mapping with cpuset is
2227 * undesirable. However, in order to preserve some of the semantics,
2228 * we fall back to check against current free page availability as
2229 * a best attempt and hopefully to minimize the impact of changing
2230 * semantics that cpuset has.
2233 if (gather_surplus_pages(h
, delta
) < 0)
2236 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2237 return_unused_surplus_pages(h
, delta
);
2244 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2247 spin_unlock(&hugetlb_lock
);
2251 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2253 struct resv_map
*resv
= vma_resv_map(vma
);
2256 * This new VMA should share its siblings reservation map if present.
2257 * The VMA will only ever have a valid reservation map pointer where
2258 * it is being copied for another still existing VMA. As that VMA
2259 * has a reference to the reservation map it cannot disappear until
2260 * after this open call completes. It is therefore safe to take a
2261 * new reference here without additional locking.
2264 kref_get(&resv
->refs
);
2267 static void resv_map_put(struct vm_area_struct
*vma
)
2269 struct resv_map
*resv
= vma_resv_map(vma
);
2273 kref_put(&resv
->refs
, resv_map_release
);
2276 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2278 struct hstate
*h
= hstate_vma(vma
);
2279 struct resv_map
*resv
= vma_resv_map(vma
);
2280 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2281 unsigned long reserve
;
2282 unsigned long start
;
2286 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2287 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2289 reserve
= (end
- start
) -
2290 region_count(&resv
->regions
, start
, end
);
2295 hugetlb_acct_memory(h
, -reserve
);
2296 hugepage_subpool_put_pages(spool
, reserve
);
2302 * We cannot handle pagefaults against hugetlb pages at all. They cause
2303 * handle_mm_fault() to try to instantiate regular-sized pages in the
2304 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2307 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2313 const struct vm_operations_struct hugetlb_vm_ops
= {
2314 .fault
= hugetlb_vm_op_fault
,
2315 .open
= hugetlb_vm_op_open
,
2316 .close
= hugetlb_vm_op_close
,
2319 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2325 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2326 vma
->vm_page_prot
)));
2328 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2329 vma
->vm_page_prot
));
2331 entry
= pte_mkyoung(entry
);
2332 entry
= pte_mkhuge(entry
);
2333 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2338 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2339 unsigned long address
, pte_t
*ptep
)
2343 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2344 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2345 update_mmu_cache(vma
, address
, ptep
);
2349 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2350 struct vm_area_struct
*vma
)
2352 pte_t
*src_pte
, *dst_pte
, entry
;
2353 struct page
*ptepage
;
2356 struct hstate
*h
= hstate_vma(vma
);
2357 unsigned long sz
= huge_page_size(h
);
2359 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2361 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2362 spinlock_t
*src_ptl
, *dst_ptl
;
2363 src_pte
= huge_pte_offset(src
, addr
);
2366 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2370 /* If the pagetables are shared don't copy or take references */
2371 if (dst_pte
== src_pte
)
2374 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
2375 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
2376 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
2377 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2379 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2380 entry
= huge_ptep_get(src_pte
);
2381 ptepage
= pte_page(entry
);
2383 page_dup_rmap(ptepage
);
2384 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2386 spin_unlock(src_ptl
);
2387 spin_unlock(dst_ptl
);
2395 static int is_hugetlb_entry_migration(pte_t pte
)
2399 if (huge_pte_none(pte
) || pte_present(pte
))
2401 swp
= pte_to_swp_entry(pte
);
2402 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2408 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2412 if (huge_pte_none(pte
) || pte_present(pte
))
2414 swp
= pte_to_swp_entry(pte
);
2415 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2421 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2422 unsigned long start
, unsigned long end
,
2423 struct page
*ref_page
)
2425 int force_flush
= 0;
2426 struct mm_struct
*mm
= vma
->vm_mm
;
2427 unsigned long address
;
2432 struct hstate
*h
= hstate_vma(vma
);
2433 unsigned long sz
= huge_page_size(h
);
2434 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2435 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2437 WARN_ON(!is_vm_hugetlb_page(vma
));
2438 BUG_ON(start
& ~huge_page_mask(h
));
2439 BUG_ON(end
& ~huge_page_mask(h
));
2441 tlb_start_vma(tlb
, vma
);
2442 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2444 for (address
= start
; address
< end
; address
+= sz
) {
2445 ptep
= huge_pte_offset(mm
, address
);
2449 ptl
= huge_pte_lock(h
, mm
, ptep
);
2450 if (huge_pmd_unshare(mm
, &address
, ptep
))
2453 pte
= huge_ptep_get(ptep
);
2454 if (huge_pte_none(pte
))
2458 * HWPoisoned hugepage is already unmapped and dropped reference
2460 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2461 huge_pte_clear(mm
, address
, ptep
);
2465 page
= pte_page(pte
);
2467 * If a reference page is supplied, it is because a specific
2468 * page is being unmapped, not a range. Ensure the page we
2469 * are about to unmap is the actual page of interest.
2472 if (page
!= ref_page
)
2476 * Mark the VMA as having unmapped its page so that
2477 * future faults in this VMA will fail rather than
2478 * looking like data was lost
2480 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2483 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2484 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2485 if (huge_pte_dirty(pte
))
2486 set_page_dirty(page
);
2488 page_remove_rmap(page
);
2489 force_flush
= !__tlb_remove_page(tlb
, page
);
2494 /* Bail out after unmapping reference page if supplied */
2503 * mmu_gather ran out of room to batch pages, we break out of
2504 * the PTE lock to avoid doing the potential expensive TLB invalidate
2505 * and page-free while holding it.
2510 if (address
< end
&& !ref_page
)
2513 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2514 tlb_end_vma(tlb
, vma
);
2517 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2518 struct vm_area_struct
*vma
, unsigned long start
,
2519 unsigned long end
, struct page
*ref_page
)
2521 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2524 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2525 * test will fail on a vma being torn down, and not grab a page table
2526 * on its way out. We're lucky that the flag has such an appropriate
2527 * name, and can in fact be safely cleared here. We could clear it
2528 * before the __unmap_hugepage_range above, but all that's necessary
2529 * is to clear it before releasing the i_mmap_mutex. This works
2530 * because in the context this is called, the VMA is about to be
2531 * destroyed and the i_mmap_mutex is held.
2533 vma
->vm_flags
&= ~VM_MAYSHARE
;
2536 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2537 unsigned long end
, struct page
*ref_page
)
2539 struct mm_struct
*mm
;
2540 struct mmu_gather tlb
;
2544 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2545 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2546 tlb_finish_mmu(&tlb
, start
, end
);
2550 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2551 * mappping it owns the reserve page for. The intention is to unmap the page
2552 * from other VMAs and let the children be SIGKILLed if they are faulting the
2555 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2556 struct page
*page
, unsigned long address
)
2558 struct hstate
*h
= hstate_vma(vma
);
2559 struct vm_area_struct
*iter_vma
;
2560 struct address_space
*mapping
;
2564 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2565 * from page cache lookup which is in HPAGE_SIZE units.
2567 address
= address
& huge_page_mask(h
);
2568 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2570 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2573 * Take the mapping lock for the duration of the table walk. As
2574 * this mapping should be shared between all the VMAs,
2575 * __unmap_hugepage_range() is called as the lock is already held
2577 mutex_lock(&mapping
->i_mmap_mutex
);
2578 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2579 /* Do not unmap the current VMA */
2580 if (iter_vma
== vma
)
2584 * Unmap the page from other VMAs without their own reserves.
2585 * They get marked to be SIGKILLed if they fault in these
2586 * areas. This is because a future no-page fault on this VMA
2587 * could insert a zeroed page instead of the data existing
2588 * from the time of fork. This would look like data corruption
2590 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2591 unmap_hugepage_range(iter_vma
, address
,
2592 address
+ huge_page_size(h
), page
);
2594 mutex_unlock(&mapping
->i_mmap_mutex
);
2600 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2601 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2602 * cannot race with other handlers or page migration.
2603 * Keep the pte_same checks anyway to make transition from the mutex easier.
2605 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2606 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2607 struct page
*pagecache_page
, spinlock_t
*ptl
)
2609 struct hstate
*h
= hstate_vma(vma
);
2610 struct page
*old_page
, *new_page
;
2611 int outside_reserve
= 0;
2612 unsigned long mmun_start
; /* For mmu_notifiers */
2613 unsigned long mmun_end
; /* For mmu_notifiers */
2615 old_page
= pte_page(pte
);
2618 /* If no-one else is actually using this page, avoid the copy
2619 * and just make the page writable */
2620 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2621 page_move_anon_rmap(old_page
, vma
, address
);
2622 set_huge_ptep_writable(vma
, address
, ptep
);
2627 * If the process that created a MAP_PRIVATE mapping is about to
2628 * perform a COW due to a shared page count, attempt to satisfy
2629 * the allocation without using the existing reserves. The pagecache
2630 * page is used to determine if the reserve at this address was
2631 * consumed or not. If reserves were used, a partial faulted mapping
2632 * at the time of fork() could consume its reserves on COW instead
2633 * of the full address range.
2635 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2636 old_page
!= pagecache_page
)
2637 outside_reserve
= 1;
2639 page_cache_get(old_page
);
2641 /* Drop page table lock as buddy allocator may be called */
2643 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2645 if (IS_ERR(new_page
)) {
2646 long err
= PTR_ERR(new_page
);
2647 page_cache_release(old_page
);
2650 * If a process owning a MAP_PRIVATE mapping fails to COW,
2651 * it is due to references held by a child and an insufficient
2652 * huge page pool. To guarantee the original mappers
2653 * reliability, unmap the page from child processes. The child
2654 * may get SIGKILLed if it later faults.
2656 if (outside_reserve
) {
2657 BUG_ON(huge_pte_none(pte
));
2658 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2659 BUG_ON(huge_pte_none(pte
));
2661 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2662 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2663 goto retry_avoidcopy
;
2665 * race occurs while re-acquiring page table
2666 * lock, and our job is done.
2673 /* Caller expects lock to be held */
2676 return VM_FAULT_OOM
;
2678 return VM_FAULT_SIGBUS
;
2682 * When the original hugepage is shared one, it does not have
2683 * anon_vma prepared.
2685 if (unlikely(anon_vma_prepare(vma
))) {
2686 page_cache_release(new_page
);
2687 page_cache_release(old_page
);
2688 /* Caller expects lock to be held */
2690 return VM_FAULT_OOM
;
2693 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2694 pages_per_huge_page(h
));
2695 __SetPageUptodate(new_page
);
2697 mmun_start
= address
& huge_page_mask(h
);
2698 mmun_end
= mmun_start
+ huge_page_size(h
);
2699 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2701 * Retake the page table lock to check for racing updates
2702 * before the page tables are altered
2705 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2706 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2707 ClearPagePrivate(new_page
);
2710 huge_ptep_clear_flush(vma
, address
, ptep
);
2711 set_huge_pte_at(mm
, address
, ptep
,
2712 make_huge_pte(vma
, new_page
, 1));
2713 page_remove_rmap(old_page
);
2714 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2715 /* Make the old page be freed below */
2716 new_page
= old_page
;
2719 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2720 page_cache_release(new_page
);
2721 page_cache_release(old_page
);
2723 /* Caller expects lock to be held */
2728 /* Return the pagecache page at a given address within a VMA */
2729 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2730 struct vm_area_struct
*vma
, unsigned long address
)
2732 struct address_space
*mapping
;
2735 mapping
= vma
->vm_file
->f_mapping
;
2736 idx
= vma_hugecache_offset(h
, vma
, address
);
2738 return find_lock_page(mapping
, idx
);
2742 * Return whether there is a pagecache page to back given address within VMA.
2743 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2745 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2746 struct vm_area_struct
*vma
, unsigned long address
)
2748 struct address_space
*mapping
;
2752 mapping
= vma
->vm_file
->f_mapping
;
2753 idx
= vma_hugecache_offset(h
, vma
, address
);
2755 page
= find_get_page(mapping
, idx
);
2758 return page
!= NULL
;
2761 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2762 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2764 struct hstate
*h
= hstate_vma(vma
);
2765 int ret
= VM_FAULT_SIGBUS
;
2770 struct address_space
*mapping
;
2775 * Currently, we are forced to kill the process in the event the
2776 * original mapper has unmapped pages from the child due to a failed
2777 * COW. Warn that such a situation has occurred as it may not be obvious
2779 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2780 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2785 mapping
= vma
->vm_file
->f_mapping
;
2786 idx
= vma_hugecache_offset(h
, vma
, address
);
2789 * Use page lock to guard against racing truncation
2790 * before we get page_table_lock.
2793 page
= find_lock_page(mapping
, idx
);
2795 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2798 page
= alloc_huge_page(vma
, address
, 0);
2800 ret
= PTR_ERR(page
);
2804 ret
= VM_FAULT_SIGBUS
;
2807 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2808 __SetPageUptodate(page
);
2810 if (vma
->vm_flags
& VM_MAYSHARE
) {
2812 struct inode
*inode
= mapping
->host
;
2814 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2821 ClearPagePrivate(page
);
2823 spin_lock(&inode
->i_lock
);
2824 inode
->i_blocks
+= blocks_per_huge_page(h
);
2825 spin_unlock(&inode
->i_lock
);
2828 if (unlikely(anon_vma_prepare(vma
))) {
2830 goto backout_unlocked
;
2836 * If memory error occurs between mmap() and fault, some process
2837 * don't have hwpoisoned swap entry for errored virtual address.
2838 * So we need to block hugepage fault by PG_hwpoison bit check.
2840 if (unlikely(PageHWPoison(page
))) {
2841 ret
= VM_FAULT_HWPOISON
|
2842 VM_FAULT_SET_HINDEX(hstate_index(h
));
2843 goto backout_unlocked
;
2848 * If we are going to COW a private mapping later, we examine the
2849 * pending reservations for this page now. This will ensure that
2850 * any allocations necessary to record that reservation occur outside
2853 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2854 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2856 goto backout_unlocked
;
2859 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
2861 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2866 if (!huge_pte_none(huge_ptep_get(ptep
)))
2870 ClearPagePrivate(page
);
2871 hugepage_add_new_anon_rmap(page
, vma
, address
);
2874 page_dup_rmap(page
);
2875 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2876 && (vma
->vm_flags
& VM_SHARED
)));
2877 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2879 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2880 /* Optimization, do the COW without a second fault */
2881 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
, ptl
);
2897 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2898 unsigned long address
, unsigned int flags
)
2904 struct page
*page
= NULL
;
2905 struct page
*pagecache_page
= NULL
;
2906 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2907 struct hstate
*h
= hstate_vma(vma
);
2909 address
&= huge_page_mask(h
);
2911 ptep
= huge_pte_offset(mm
, address
);
2913 entry
= huge_ptep_get(ptep
);
2914 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2915 migration_entry_wait_huge(vma
, mm
, ptep
);
2917 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2918 return VM_FAULT_HWPOISON_LARGE
|
2919 VM_FAULT_SET_HINDEX(hstate_index(h
));
2922 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2924 return VM_FAULT_OOM
;
2927 * Serialize hugepage allocation and instantiation, so that we don't
2928 * get spurious allocation failures if two CPUs race to instantiate
2929 * the same page in the page cache.
2931 mutex_lock(&hugetlb_instantiation_mutex
);
2932 entry
= huge_ptep_get(ptep
);
2933 if (huge_pte_none(entry
)) {
2934 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2941 * If we are going to COW the mapping later, we examine the pending
2942 * reservations for this page now. This will ensure that any
2943 * allocations necessary to record that reservation occur outside the
2944 * spinlock. For private mappings, we also lookup the pagecache
2945 * page now as it is used to determine if a reservation has been
2948 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
2949 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2954 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2955 pagecache_page
= hugetlbfs_pagecache_page(h
,
2960 * hugetlb_cow() requires page locks of pte_page(entry) and
2961 * pagecache_page, so here we need take the former one
2962 * when page != pagecache_page or !pagecache_page.
2963 * Note that locking order is always pagecache_page -> page,
2964 * so no worry about deadlock.
2966 page
= pte_page(entry
);
2968 if (page
!= pagecache_page
)
2971 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
2973 /* Check for a racing update before calling hugetlb_cow */
2974 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2978 if (flags
& FAULT_FLAG_WRITE
) {
2979 if (!huge_pte_write(entry
)) {
2980 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2981 pagecache_page
, ptl
);
2984 entry
= huge_pte_mkdirty(entry
);
2986 entry
= pte_mkyoung(entry
);
2987 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2988 flags
& FAULT_FLAG_WRITE
))
2989 update_mmu_cache(vma
, address
, ptep
);
2994 if (pagecache_page
) {
2995 unlock_page(pagecache_page
);
2996 put_page(pagecache_page
);
2998 if (page
!= pagecache_page
)
3003 mutex_unlock(&hugetlb_instantiation_mutex
);
3008 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3009 struct page
**pages
, struct vm_area_struct
**vmas
,
3010 unsigned long *position
, unsigned long *nr_pages
,
3011 long i
, unsigned int flags
)
3013 unsigned long pfn_offset
;
3014 unsigned long vaddr
= *position
;
3015 unsigned long remainder
= *nr_pages
;
3016 struct hstate
*h
= hstate_vma(vma
);
3018 while (vaddr
< vma
->vm_end
&& remainder
) {
3020 spinlock_t
*ptl
= NULL
;
3025 * Some archs (sparc64, sh*) have multiple pte_ts to
3026 * each hugepage. We have to make sure we get the
3027 * first, for the page indexing below to work.
3029 * Note that page table lock is not held when pte is null.
3031 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
3033 ptl
= huge_pte_lock(h
, mm
, pte
);
3034 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
3037 * When coredumping, it suits get_dump_page if we just return
3038 * an error where there's an empty slot with no huge pagecache
3039 * to back it. This way, we avoid allocating a hugepage, and
3040 * the sparse dumpfile avoids allocating disk blocks, but its
3041 * huge holes still show up with zeroes where they need to be.
3043 if (absent
&& (flags
& FOLL_DUMP
) &&
3044 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
3052 * We need call hugetlb_fault for both hugepages under migration
3053 * (in which case hugetlb_fault waits for the migration,) and
3054 * hwpoisoned hugepages (in which case we need to prevent the
3055 * caller from accessing to them.) In order to do this, we use
3056 * here is_swap_pte instead of is_hugetlb_entry_migration and
3057 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3058 * both cases, and because we can't follow correct pages
3059 * directly from any kind of swap entries.
3061 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
3062 ((flags
& FOLL_WRITE
) &&
3063 !huge_pte_write(huge_ptep_get(pte
)))) {
3068 ret
= hugetlb_fault(mm
, vma
, vaddr
,
3069 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
3070 if (!(ret
& VM_FAULT_ERROR
))
3077 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
3078 page
= pte_page(huge_ptep_get(pte
));
3081 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3092 if (vaddr
< vma
->vm_end
&& remainder
&&
3093 pfn_offset
< pages_per_huge_page(h
)) {
3095 * We use pfn_offset to avoid touching the pageframes
3096 * of this compound page.
3102 *nr_pages
= remainder
;
3105 return i
? i
: -EFAULT
;
3108 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3109 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3111 struct mm_struct
*mm
= vma
->vm_mm
;
3112 unsigned long start
= address
;
3115 struct hstate
*h
= hstate_vma(vma
);
3116 unsigned long pages
= 0;
3118 BUG_ON(address
>= end
);
3119 flush_cache_range(vma
, address
, end
);
3121 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3122 for (; address
< end
; address
+= huge_page_size(h
)) {
3124 ptep
= huge_pte_offset(mm
, address
);
3127 ptl
= huge_pte_lock(h
, mm
, ptep
);
3128 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3133 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3134 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3135 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3136 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3137 set_huge_pte_at(mm
, address
, ptep
, pte
);
3143 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3144 * may have cleared our pud entry and done put_page on the page table:
3145 * once we release i_mmap_mutex, another task can do the final put_page
3146 * and that page table be reused and filled with junk.
3148 flush_tlb_range(vma
, start
, end
);
3149 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3151 return pages
<< h
->order
;
3154 int hugetlb_reserve_pages(struct inode
*inode
,
3156 struct vm_area_struct
*vma
,
3157 vm_flags_t vm_flags
)
3160 struct hstate
*h
= hstate_inode(inode
);
3161 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3164 * Only apply hugepage reservation if asked. At fault time, an
3165 * attempt will be made for VM_NORESERVE to allocate a page
3166 * without using reserves
3168 if (vm_flags
& VM_NORESERVE
)
3172 * Shared mappings base their reservation on the number of pages that
3173 * are already allocated on behalf of the file. Private mappings need
3174 * to reserve the full area even if read-only as mprotect() may be
3175 * called to make the mapping read-write. Assume !vma is a shm mapping
3177 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3178 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3180 struct resv_map
*resv_map
= resv_map_alloc();
3186 set_vma_resv_map(vma
, resv_map
);
3187 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3195 /* There must be enough pages in the subpool for the mapping */
3196 if (hugepage_subpool_get_pages(spool
, chg
)) {
3202 * Check enough hugepages are available for the reservation.
3203 * Hand the pages back to the subpool if there are not
3205 ret
= hugetlb_acct_memory(h
, chg
);
3207 hugepage_subpool_put_pages(spool
, chg
);
3212 * Account for the reservations made. Shared mappings record regions
3213 * that have reservations as they are shared by multiple VMAs.
3214 * When the last VMA disappears, the region map says how much
3215 * the reservation was and the page cache tells how much of
3216 * the reservation was consumed. Private mappings are per-VMA and
3217 * only the consumed reservations are tracked. When the VMA
3218 * disappears, the original reservation is the VMA size and the
3219 * consumed reservations are stored in the map. Hence, nothing
3220 * else has to be done for private mappings here
3222 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3223 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3231 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3233 struct hstate
*h
= hstate_inode(inode
);
3234 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3235 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3237 spin_lock(&inode
->i_lock
);
3238 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3239 spin_unlock(&inode
->i_lock
);
3241 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3242 hugetlb_acct_memory(h
, -(chg
- freed
));
3245 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3246 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3247 struct vm_area_struct
*vma
,
3248 unsigned long addr
, pgoff_t idx
)
3250 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3252 unsigned long sbase
= saddr
& PUD_MASK
;
3253 unsigned long s_end
= sbase
+ PUD_SIZE
;
3255 /* Allow segments to share if only one is marked locked */
3256 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3257 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3260 * match the virtual addresses, permission and the alignment of the
3263 if (pmd_index(addr
) != pmd_index(saddr
) ||
3264 vm_flags
!= svm_flags
||
3265 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3271 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3273 unsigned long base
= addr
& PUD_MASK
;
3274 unsigned long end
= base
+ PUD_SIZE
;
3277 * check on proper vm_flags and page table alignment
3279 if (vma
->vm_flags
& VM_MAYSHARE
&&
3280 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3286 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3287 * and returns the corresponding pte. While this is not necessary for the
3288 * !shared pmd case because we can allocate the pmd later as well, it makes the
3289 * code much cleaner. pmd allocation is essential for the shared case because
3290 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3291 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3292 * bad pmd for sharing.
3294 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3296 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3297 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3298 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3300 struct vm_area_struct
*svma
;
3301 unsigned long saddr
;
3306 if (!vma_shareable(vma
, addr
))
3307 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3309 mutex_lock(&mapping
->i_mmap_mutex
);
3310 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3314 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3316 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3318 get_page(virt_to_page(spte
));
3327 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, spte
);
3330 pud_populate(mm
, pud
,
3331 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3333 put_page(virt_to_page(spte
));
3336 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3337 mutex_unlock(&mapping
->i_mmap_mutex
);
3342 * unmap huge page backed by shared pte.
3344 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3345 * indicated by page_count > 1, unmap is achieved by clearing pud and
3346 * decrementing the ref count. If count == 1, the pte page is not shared.
3348 * called with page table lock held.
3350 * returns: 1 successfully unmapped a shared pte page
3351 * 0 the underlying pte page is not shared, or it is the last user
3353 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3355 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3356 pud_t
*pud
= pud_offset(pgd
, *addr
);
3358 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3359 if (page_count(virt_to_page(ptep
)) == 1)
3363 put_page(virt_to_page(ptep
));
3364 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3367 #define want_pmd_share() (1)
3368 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3369 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3373 #define want_pmd_share() (0)
3374 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3376 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3377 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3378 unsigned long addr
, unsigned long sz
)
3384 pgd
= pgd_offset(mm
, addr
);
3385 pud
= pud_alloc(mm
, pgd
, addr
);
3387 if (sz
== PUD_SIZE
) {
3390 BUG_ON(sz
!= PMD_SIZE
);
3391 if (want_pmd_share() && pud_none(*pud
))
3392 pte
= huge_pmd_share(mm
, addr
, pud
);
3394 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3397 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3402 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3408 pgd
= pgd_offset(mm
, addr
);
3409 if (pgd_present(*pgd
)) {
3410 pud
= pud_offset(pgd
, addr
);
3411 if (pud_present(*pud
)) {
3413 return (pte_t
*)pud
;
3414 pmd
= pmd_offset(pud
, addr
);
3417 return (pte_t
*) pmd
;
3421 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3422 pmd_t
*pmd
, int write
)
3426 page
= pte_page(*(pte_t
*)pmd
);
3428 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3433 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3434 pud_t
*pud
, int write
)
3438 page
= pte_page(*(pte_t
*)pud
);
3440 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3444 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3446 /* Can be overriden by architectures */
3447 __attribute__((weak
)) struct page
*
3448 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3449 pud_t
*pud
, int write
)
3455 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3457 #ifdef CONFIG_MEMORY_FAILURE
3459 /* Should be called in hugetlb_lock */
3460 static int is_hugepage_on_freelist(struct page
*hpage
)
3464 struct hstate
*h
= page_hstate(hpage
);
3465 int nid
= page_to_nid(hpage
);
3467 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3474 * This function is called from memory failure code.
3475 * Assume the caller holds page lock of the head page.
3477 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3479 struct hstate
*h
= page_hstate(hpage
);
3480 int nid
= page_to_nid(hpage
);
3483 spin_lock(&hugetlb_lock
);
3484 if (is_hugepage_on_freelist(hpage
)) {
3486 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3487 * but dangling hpage->lru can trigger list-debug warnings
3488 * (this happens when we call unpoison_memory() on it),
3489 * so let it point to itself with list_del_init().
3491 list_del_init(&hpage
->lru
);
3492 set_page_refcounted(hpage
);
3493 h
->free_huge_pages
--;
3494 h
->free_huge_pages_node
[nid
]--;
3497 spin_unlock(&hugetlb_lock
);
3502 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
3504 VM_BUG_ON(!PageHead(page
));
3505 if (!get_page_unless_zero(page
))
3507 spin_lock(&hugetlb_lock
);
3508 list_move_tail(&page
->lru
, list
);
3509 spin_unlock(&hugetlb_lock
);
3513 void putback_active_hugepage(struct page
*page
)
3515 VM_BUG_ON(!PageHead(page
));
3516 spin_lock(&hugetlb_lock
);
3517 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
3518 spin_unlock(&hugetlb_lock
);
3522 bool is_hugepage_active(struct page
*page
)
3524 VM_BUG_ON(!PageHuge(page
));
3526 * This function can be called for a tail page because the caller,
3527 * scan_movable_pages, scans through a given pfn-range which typically
3528 * covers one memory block. In systems using gigantic hugepage (1GB
3529 * for x86_64,) a hugepage is larger than a memory block, and we don't
3530 * support migrating such large hugepages for now, so return false
3531 * when called for tail pages.
3536 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3537 * so we should return false for them.
3539 if (unlikely(PageHWPoison(page
)))
3541 return page_count(page
) > 0;