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/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
38 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
39 unsigned long hugepages_treat_as_movable
;
41 int hugetlb_max_hstate __read_mostly
;
42 unsigned int default_hstate_idx
;
43 struct hstate hstates
[HUGE_MAX_HSTATE
];
45 __initdata
LIST_HEAD(huge_boot_pages
);
47 /* for command line parsing */
48 static struct hstate
* __initdata parsed_hstate
;
49 static unsigned long __initdata default_hstate_max_huge_pages
;
50 static unsigned long __initdata default_hstate_size
;
53 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
54 * free_huge_pages, and surplus_huge_pages.
56 DEFINE_SPINLOCK(hugetlb_lock
);
59 * Serializes faults on the same logical page. This is used to
60 * prevent spurious OOMs when the hugepage pool is fully utilized.
62 static int num_fault_mutexes
;
63 static struct mutex
*htlb_fault_mutex_table ____cacheline_aligned_in_smp
;
65 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
67 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
69 spin_unlock(&spool
->lock
);
71 /* If no pages are used, and no other handles to the subpool
72 * remain, free the subpool the subpool remain */
77 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
79 struct hugepage_subpool
*spool
;
81 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
85 spin_lock_init(&spool
->lock
);
87 spool
->max_hpages
= nr_blocks
;
88 spool
->used_hpages
= 0;
93 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
95 spin_lock(&spool
->lock
);
96 BUG_ON(!spool
->count
);
98 unlock_or_release_subpool(spool
);
101 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
109 spin_lock(&spool
->lock
);
110 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
111 spool
->used_hpages
+= delta
;
115 spin_unlock(&spool
->lock
);
120 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
126 spin_lock(&spool
->lock
);
127 spool
->used_hpages
-= delta
;
128 /* If hugetlbfs_put_super couldn't free spool due to
129 * an outstanding quota reference, free it now. */
130 unlock_or_release_subpool(spool
);
133 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
135 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
138 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
140 return subpool_inode(file_inode(vma
->vm_file
));
144 * Region tracking -- allows tracking of reservations and instantiated pages
145 * across the pages in a mapping.
147 * The region data structures are embedded into a resv_map and
148 * protected by a resv_map's lock
151 struct list_head link
;
156 static long region_add(struct resv_map
*resv
, long f
, long t
)
158 struct list_head
*head
= &resv
->regions
;
159 struct file_region
*rg
, *nrg
, *trg
;
161 spin_lock(&resv
->lock
);
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg
, head
, link
)
167 /* Round our left edge to the current segment if it encloses us. */
171 /* Check for and consume any regions we now overlap with. */
173 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
174 if (&rg
->link
== head
)
179 /* If this area reaches higher then extend our area to
180 * include it completely. If this is not the first area
181 * which we intend to reuse, free it. */
191 spin_unlock(&resv
->lock
);
195 static long region_chg(struct resv_map
*resv
, long f
, long t
)
197 struct list_head
*head
= &resv
->regions
;
198 struct file_region
*rg
, *nrg
= NULL
;
202 spin_lock(&resv
->lock
);
203 /* Locate the region we are before or in. */
204 list_for_each_entry(rg
, head
, link
)
208 /* If we are below the current region then a new region is required.
209 * Subtle, allocate a new region at the position but make it zero
210 * size such that we can guarantee to record the reservation. */
211 if (&rg
->link
== head
|| t
< rg
->from
) {
213 spin_unlock(&resv
->lock
);
214 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
220 INIT_LIST_HEAD(&nrg
->link
);
224 list_add(&nrg
->link
, rg
->link
.prev
);
229 /* Round our left edge to the current segment if it encloses us. */
234 /* Check for and consume any regions we now overlap with. */
235 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
236 if (&rg
->link
== head
)
241 /* We overlap with this area, if it extends further than
242 * us then we must extend ourselves. Account for its
243 * existing reservation. */
248 chg
-= rg
->to
- rg
->from
;
252 spin_unlock(&resv
->lock
);
253 /* We already know we raced and no longer need the new region */
257 spin_unlock(&resv
->lock
);
261 static long region_truncate(struct resv_map
*resv
, long end
)
263 struct list_head
*head
= &resv
->regions
;
264 struct file_region
*rg
, *trg
;
267 spin_lock(&resv
->lock
);
268 /* Locate the region we are either in or before. */
269 list_for_each_entry(rg
, head
, link
)
272 if (&rg
->link
== head
)
275 /* If we are in the middle of a region then adjust it. */
276 if (end
> rg
->from
) {
279 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
282 /* Drop any remaining regions. */
283 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
284 if (&rg
->link
== head
)
286 chg
+= rg
->to
- rg
->from
;
292 spin_unlock(&resv
->lock
);
296 static long region_count(struct resv_map
*resv
, long f
, long t
)
298 struct list_head
*head
= &resv
->regions
;
299 struct file_region
*rg
;
302 spin_lock(&resv
->lock
);
303 /* Locate each segment we overlap with, and count that overlap. */
304 list_for_each_entry(rg
, head
, link
) {
313 seg_from
= max(rg
->from
, f
);
314 seg_to
= min(rg
->to
, t
);
316 chg
+= seg_to
- seg_from
;
318 spin_unlock(&resv
->lock
);
324 * Convert the address within this vma to the page offset within
325 * the mapping, in pagecache page units; huge pages here.
327 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
328 struct vm_area_struct
*vma
, unsigned long address
)
330 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
331 (vma
->vm_pgoff
>> huge_page_order(h
));
334 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
335 unsigned long address
)
337 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
341 * Return the size of the pages allocated when backing a VMA. In the majority
342 * cases this will be same size as used by the page table entries.
344 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
346 struct hstate
*hstate
;
348 if (!is_vm_hugetlb_page(vma
))
351 hstate
= hstate_vma(vma
);
353 return 1UL << huge_page_shift(hstate
);
355 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
358 * Return the page size being used by the MMU to back a VMA. In the majority
359 * of cases, the page size used by the kernel matches the MMU size. On
360 * architectures where it differs, an architecture-specific version of this
361 * function is required.
363 #ifndef vma_mmu_pagesize
364 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
366 return vma_kernel_pagesize(vma
);
371 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
372 * bits of the reservation map pointer, which are always clear due to
375 #define HPAGE_RESV_OWNER (1UL << 0)
376 #define HPAGE_RESV_UNMAPPED (1UL << 1)
377 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
380 * These helpers are used to track how many pages are reserved for
381 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
382 * is guaranteed to have their future faults succeed.
384 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
385 * the reserve counters are updated with the hugetlb_lock held. It is safe
386 * to reset the VMA at fork() time as it is not in use yet and there is no
387 * chance of the global counters getting corrupted as a result of the values.
389 * The private mapping reservation is represented in a subtly different
390 * manner to a shared mapping. A shared mapping has a region map associated
391 * with the underlying file, this region map represents the backing file
392 * pages which have ever had a reservation assigned which this persists even
393 * after the page is instantiated. A private mapping has a region map
394 * associated with the original mmap which is attached to all VMAs which
395 * reference it, this region map represents those offsets which have consumed
396 * reservation ie. where pages have been instantiated.
398 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
400 return (unsigned long)vma
->vm_private_data
;
403 static void set_vma_private_data(struct vm_area_struct
*vma
,
406 vma
->vm_private_data
= (void *)value
;
409 struct resv_map
*resv_map_alloc(void)
411 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
415 kref_init(&resv_map
->refs
);
416 spin_lock_init(&resv_map
->lock
);
417 INIT_LIST_HEAD(&resv_map
->regions
);
422 void resv_map_release(struct kref
*ref
)
424 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
426 /* Clear out any active regions before we release the map. */
427 region_truncate(resv_map
, 0);
431 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
433 return inode
->i_mapping
->private_data
;
436 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
438 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
439 if (vma
->vm_flags
& VM_MAYSHARE
) {
440 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
441 struct inode
*inode
= mapping
->host
;
443 return inode_resv_map(inode
);
446 return (struct resv_map
*)(get_vma_private_data(vma
) &
451 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
453 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
454 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
456 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
457 HPAGE_RESV_MASK
) | (unsigned long)map
);
460 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
462 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
463 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
465 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
468 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
470 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
472 return (get_vma_private_data(vma
) & flag
) != 0;
475 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
476 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
478 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
479 if (!(vma
->vm_flags
& VM_MAYSHARE
))
480 vma
->vm_private_data
= (void *)0;
483 /* Returns true if the VMA has associated reserve pages */
484 static int vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
486 if (vma
->vm_flags
& VM_NORESERVE
) {
488 * This address is already reserved by other process(chg == 0),
489 * so, we should decrement reserved count. Without decrementing,
490 * reserve count remains after releasing inode, because this
491 * allocated page will go into page cache and is regarded as
492 * coming from reserved pool in releasing step. Currently, we
493 * don't have any other solution to deal with this situation
494 * properly, so add work-around here.
496 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
502 /* Shared mappings always use reserves */
503 if (vma
->vm_flags
& VM_MAYSHARE
)
507 * Only the process that called mmap() has reserves for
510 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
516 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
518 int nid
= page_to_nid(page
);
519 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
520 h
->free_huge_pages
++;
521 h
->free_huge_pages_node
[nid
]++;
524 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
528 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
529 if (!is_migrate_isolate_page(page
))
532 * if 'non-isolated free hugepage' not found on the list,
533 * the allocation fails.
535 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
537 list_move(&page
->lru
, &h
->hugepage_activelist
);
538 set_page_refcounted(page
);
539 h
->free_huge_pages
--;
540 h
->free_huge_pages_node
[nid
]--;
544 /* Movability of hugepages depends on migration support. */
545 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
547 if (hugepages_treat_as_movable
|| hugepage_migration_support(h
))
548 return GFP_HIGHUSER_MOVABLE
;
553 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
554 struct vm_area_struct
*vma
,
555 unsigned long address
, int avoid_reserve
,
558 struct page
*page
= NULL
;
559 struct mempolicy
*mpol
;
560 nodemask_t
*nodemask
;
561 struct zonelist
*zonelist
;
564 unsigned int cpuset_mems_cookie
;
567 * A child process with MAP_PRIVATE mappings created by their parent
568 * have no page reserves. This check ensures that reservations are
569 * not "stolen". The child may still get SIGKILLed
571 if (!vma_has_reserves(vma
, chg
) &&
572 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
575 /* If reserves cannot be used, ensure enough pages are in the pool */
576 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
580 cpuset_mems_cookie
= read_mems_allowed_begin();
581 zonelist
= huge_zonelist(vma
, address
,
582 htlb_alloc_mask(h
), &mpol
, &nodemask
);
584 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
585 MAX_NR_ZONES
- 1, nodemask
) {
586 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask(h
))) {
587 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
591 if (!vma_has_reserves(vma
, chg
))
594 SetPagePrivate(page
);
595 h
->resv_huge_pages
--;
602 if (unlikely(!page
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
610 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
614 VM_BUG_ON(h
->order
>= MAX_ORDER
);
617 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
618 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
619 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
620 1 << PG_referenced
| 1 << PG_dirty
|
621 1 << PG_active
| 1 << PG_reserved
|
622 1 << PG_private
| 1 << PG_writeback
);
624 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
625 set_compound_page_dtor(page
, NULL
);
626 set_page_refcounted(page
);
627 arch_release_hugepage(page
);
628 __free_pages(page
, huge_page_order(h
));
631 struct hstate
*size_to_hstate(unsigned long size
)
636 if (huge_page_size(h
) == size
)
642 static void free_huge_page(struct page
*page
)
645 * Can't pass hstate in here because it is called from the
646 * compound page destructor.
648 struct hstate
*h
= page_hstate(page
);
649 int nid
= page_to_nid(page
);
650 struct hugepage_subpool
*spool
=
651 (struct hugepage_subpool
*)page_private(page
);
652 bool restore_reserve
;
654 set_page_private(page
, 0);
655 page
->mapping
= NULL
;
656 BUG_ON(page_count(page
));
657 BUG_ON(page_mapcount(page
));
658 restore_reserve
= PagePrivate(page
);
659 ClearPagePrivate(page
);
661 spin_lock(&hugetlb_lock
);
662 hugetlb_cgroup_uncharge_page(hstate_index(h
),
663 pages_per_huge_page(h
), page
);
665 h
->resv_huge_pages
++;
667 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
668 /* remove the page from active list */
669 list_del(&page
->lru
);
670 update_and_free_page(h
, page
);
671 h
->surplus_huge_pages
--;
672 h
->surplus_huge_pages_node
[nid
]--;
674 arch_clear_hugepage_flags(page
);
675 enqueue_huge_page(h
, page
);
677 spin_unlock(&hugetlb_lock
);
678 hugepage_subpool_put_pages(spool
, 1);
681 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
683 INIT_LIST_HEAD(&page
->lru
);
684 set_compound_page_dtor(page
, free_huge_page
);
685 spin_lock(&hugetlb_lock
);
686 set_hugetlb_cgroup(page
, NULL
);
688 h
->nr_huge_pages_node
[nid
]++;
689 spin_unlock(&hugetlb_lock
);
690 put_page(page
); /* free it into the hugepage allocator */
693 static void __init
prep_compound_gigantic_page(struct page
*page
,
697 int nr_pages
= 1 << order
;
698 struct page
*p
= page
+ 1;
700 /* we rely on prep_new_huge_page to set the destructor */
701 set_compound_order(page
, order
);
703 __ClearPageReserved(page
);
704 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
707 * For gigantic hugepages allocated through bootmem at
708 * boot, it's safer to be consistent with the not-gigantic
709 * hugepages and clear the PG_reserved bit from all tail pages
710 * too. Otherwse drivers using get_user_pages() to access tail
711 * pages may get the reference counting wrong if they see
712 * PG_reserved set on a tail page (despite the head page not
713 * having PG_reserved set). Enforcing this consistency between
714 * head and tail pages allows drivers to optimize away a check
715 * on the head page when they need know if put_page() is needed
716 * after get_user_pages().
718 __ClearPageReserved(p
);
719 set_page_count(p
, 0);
720 p
->first_page
= page
;
725 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
726 * transparent huge pages. See the PageTransHuge() documentation for more
729 int PageHuge(struct page
*page
)
731 if (!PageCompound(page
))
734 page
= compound_head(page
);
735 return get_compound_page_dtor(page
) == free_huge_page
;
737 EXPORT_SYMBOL_GPL(PageHuge
);
740 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
741 * normal or transparent huge pages.
743 int PageHeadHuge(struct page
*page_head
)
745 if (!PageHead(page_head
))
748 return get_compound_page_dtor(page_head
) == free_huge_page
;
751 pgoff_t
__basepage_index(struct page
*page
)
753 struct page
*page_head
= compound_head(page
);
754 pgoff_t index
= page_index(page_head
);
755 unsigned long compound_idx
;
757 if (!PageHuge(page_head
))
758 return page_index(page
);
760 if (compound_order(page_head
) >= MAX_ORDER
)
761 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
763 compound_idx
= page
- page_head
;
765 return (index
<< compound_order(page_head
)) + compound_idx
;
768 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
772 if (h
->order
>= MAX_ORDER
)
775 page
= alloc_pages_exact_node(nid
,
776 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
777 __GFP_REPEAT
|__GFP_NOWARN
,
780 if (arch_prepare_hugepage(page
)) {
781 __free_pages(page
, huge_page_order(h
));
784 prep_new_huge_page(h
, page
, nid
);
791 * common helper functions for hstate_next_node_to_{alloc|free}.
792 * We may have allocated or freed a huge page based on a different
793 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
794 * be outside of *nodes_allowed. Ensure that we use an allowed
795 * node for alloc or free.
797 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
799 nid
= next_node(nid
, *nodes_allowed
);
800 if (nid
== MAX_NUMNODES
)
801 nid
= first_node(*nodes_allowed
);
802 VM_BUG_ON(nid
>= MAX_NUMNODES
);
807 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
809 if (!node_isset(nid
, *nodes_allowed
))
810 nid
= next_node_allowed(nid
, nodes_allowed
);
815 * returns the previously saved node ["this node"] from which to
816 * allocate a persistent huge page for the pool and advance the
817 * next node from which to allocate, handling wrap at end of node
820 static int hstate_next_node_to_alloc(struct hstate
*h
,
821 nodemask_t
*nodes_allowed
)
825 VM_BUG_ON(!nodes_allowed
);
827 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
828 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
834 * helper for free_pool_huge_page() - return the previously saved
835 * node ["this node"] from which to free a huge page. Advance the
836 * next node id whether or not we find a free huge page to free so
837 * that the next attempt to free addresses the next node.
839 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
843 VM_BUG_ON(!nodes_allowed
);
845 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
846 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
851 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
852 for (nr_nodes = nodes_weight(*mask); \
854 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
857 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
858 for (nr_nodes = nodes_weight(*mask); \
860 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
863 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
869 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
870 page
= alloc_fresh_huge_page_node(h
, node
);
878 count_vm_event(HTLB_BUDDY_PGALLOC
);
880 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
886 * Free huge page from pool from next node to free.
887 * Attempt to keep persistent huge pages more or less
888 * balanced over allowed nodes.
889 * Called with hugetlb_lock locked.
891 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
897 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
899 * If we're returning unused surplus pages, only examine
900 * nodes with surplus pages.
902 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
903 !list_empty(&h
->hugepage_freelists
[node
])) {
905 list_entry(h
->hugepage_freelists
[node
].next
,
907 list_del(&page
->lru
);
908 h
->free_huge_pages
--;
909 h
->free_huge_pages_node
[node
]--;
911 h
->surplus_huge_pages
--;
912 h
->surplus_huge_pages_node
[node
]--;
914 update_and_free_page(h
, page
);
924 * Dissolve a given free hugepage into free buddy pages. This function does
925 * nothing for in-use (including surplus) hugepages.
927 static void dissolve_free_huge_page(struct page
*page
)
929 spin_lock(&hugetlb_lock
);
930 if (PageHuge(page
) && !page_count(page
)) {
931 struct hstate
*h
= page_hstate(page
);
932 int nid
= page_to_nid(page
);
933 list_del(&page
->lru
);
934 h
->free_huge_pages
--;
935 h
->free_huge_pages_node
[nid
]--;
936 update_and_free_page(h
, page
);
938 spin_unlock(&hugetlb_lock
);
942 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
943 * make specified memory blocks removable from the system.
944 * Note that start_pfn should aligned with (minimum) hugepage size.
946 void dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
948 unsigned int order
= 8 * sizeof(void *);
952 /* Set scan step to minimum hugepage size */
954 if (order
> huge_page_order(h
))
955 order
= huge_page_order(h
);
956 VM_BUG_ON(!IS_ALIGNED(start_pfn
, 1 << order
));
957 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << order
)
958 dissolve_free_huge_page(pfn_to_page(pfn
));
961 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
966 if (h
->order
>= MAX_ORDER
)
970 * Assume we will successfully allocate the surplus page to
971 * prevent racing processes from causing the surplus to exceed
974 * This however introduces a different race, where a process B
975 * tries to grow the static hugepage pool while alloc_pages() is
976 * called by process A. B will only examine the per-node
977 * counters in determining if surplus huge pages can be
978 * converted to normal huge pages in adjust_pool_surplus(). A
979 * won't be able to increment the per-node counter, until the
980 * lock is dropped by B, but B doesn't drop hugetlb_lock until
981 * no more huge pages can be converted from surplus to normal
982 * state (and doesn't try to convert again). Thus, we have a
983 * case where a surplus huge page exists, the pool is grown, and
984 * the surplus huge page still exists after, even though it
985 * should just have been converted to a normal huge page. This
986 * does not leak memory, though, as the hugepage will be freed
987 * once it is out of use. It also does not allow the counters to
988 * go out of whack in adjust_pool_surplus() as we don't modify
989 * the node values until we've gotten the hugepage and only the
990 * per-node value is checked there.
992 spin_lock(&hugetlb_lock
);
993 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
994 spin_unlock(&hugetlb_lock
);
998 h
->surplus_huge_pages
++;
1000 spin_unlock(&hugetlb_lock
);
1002 if (nid
== NUMA_NO_NODE
)
1003 page
= alloc_pages(htlb_alloc_mask(h
)|__GFP_COMP
|
1004 __GFP_REPEAT
|__GFP_NOWARN
,
1005 huge_page_order(h
));
1007 page
= alloc_pages_exact_node(nid
,
1008 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
1009 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
1011 if (page
&& arch_prepare_hugepage(page
)) {
1012 __free_pages(page
, huge_page_order(h
));
1016 spin_lock(&hugetlb_lock
);
1018 INIT_LIST_HEAD(&page
->lru
);
1019 r_nid
= page_to_nid(page
);
1020 set_compound_page_dtor(page
, free_huge_page
);
1021 set_hugetlb_cgroup(page
, NULL
);
1023 * We incremented the global counters already
1025 h
->nr_huge_pages_node
[r_nid
]++;
1026 h
->surplus_huge_pages_node
[r_nid
]++;
1027 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1030 h
->surplus_huge_pages
--;
1031 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1033 spin_unlock(&hugetlb_lock
);
1039 * This allocation function is useful in the context where vma is irrelevant.
1040 * E.g. soft-offlining uses this function because it only cares physical
1041 * address of error page.
1043 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1045 struct page
*page
= NULL
;
1047 spin_lock(&hugetlb_lock
);
1048 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1049 page
= dequeue_huge_page_node(h
, nid
);
1050 spin_unlock(&hugetlb_lock
);
1053 page
= alloc_buddy_huge_page(h
, nid
);
1059 * Increase the hugetlb pool such that it can accommodate a reservation
1062 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1064 struct list_head surplus_list
;
1065 struct page
*page
, *tmp
;
1067 int needed
, allocated
;
1068 bool alloc_ok
= true;
1070 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1072 h
->resv_huge_pages
+= delta
;
1077 INIT_LIST_HEAD(&surplus_list
);
1081 spin_unlock(&hugetlb_lock
);
1082 for (i
= 0; i
< needed
; i
++) {
1083 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1088 list_add(&page
->lru
, &surplus_list
);
1093 * After retaking hugetlb_lock, we need to recalculate 'needed'
1094 * because either resv_huge_pages or free_huge_pages may have changed.
1096 spin_lock(&hugetlb_lock
);
1097 needed
= (h
->resv_huge_pages
+ delta
) -
1098 (h
->free_huge_pages
+ allocated
);
1103 * We were not able to allocate enough pages to
1104 * satisfy the entire reservation so we free what
1105 * we've allocated so far.
1110 * The surplus_list now contains _at_least_ the number of extra pages
1111 * needed to accommodate the reservation. Add the appropriate number
1112 * of pages to the hugetlb pool and free the extras back to the buddy
1113 * allocator. Commit the entire reservation here to prevent another
1114 * process from stealing the pages as they are added to the pool but
1115 * before they are reserved.
1117 needed
+= allocated
;
1118 h
->resv_huge_pages
+= delta
;
1121 /* Free the needed pages to the hugetlb pool */
1122 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1126 * This page is now managed by the hugetlb allocator and has
1127 * no users -- drop the buddy allocator's reference.
1129 put_page_testzero(page
);
1130 VM_BUG_ON_PAGE(page_count(page
), page
);
1131 enqueue_huge_page(h
, page
);
1134 spin_unlock(&hugetlb_lock
);
1136 /* Free unnecessary surplus pages to the buddy allocator */
1137 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1139 spin_lock(&hugetlb_lock
);
1145 * When releasing a hugetlb pool reservation, any surplus pages that were
1146 * allocated to satisfy the reservation must be explicitly freed if they were
1148 * Called with hugetlb_lock held.
1150 static void return_unused_surplus_pages(struct hstate
*h
,
1151 unsigned long unused_resv_pages
)
1153 unsigned long nr_pages
;
1155 /* Uncommit the reservation */
1156 h
->resv_huge_pages
-= unused_resv_pages
;
1158 /* Cannot return gigantic pages currently */
1159 if (h
->order
>= MAX_ORDER
)
1162 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1165 * We want to release as many surplus pages as possible, spread
1166 * evenly across all nodes with memory. Iterate across these nodes
1167 * until we can no longer free unreserved surplus pages. This occurs
1168 * when the nodes with surplus pages have no free pages.
1169 * free_pool_huge_page() will balance the the freed pages across the
1170 * on-line nodes with memory and will handle the hstate accounting.
1172 while (nr_pages
--) {
1173 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1175 cond_resched_lock(&hugetlb_lock
);
1180 * Determine if the huge page at addr within the vma has an associated
1181 * reservation. Where it does not we will need to logically increase
1182 * reservation and actually increase subpool usage before an allocation
1183 * can occur. Where any new reservation would be required the
1184 * reservation change is prepared, but not committed. Once the page
1185 * has been allocated from the subpool and instantiated the change should
1186 * be committed via vma_commit_reservation. No action is required on
1189 static long vma_needs_reservation(struct hstate
*h
,
1190 struct vm_area_struct
*vma
, unsigned long addr
)
1192 struct resv_map
*resv
;
1196 resv
= vma_resv_map(vma
);
1200 idx
= vma_hugecache_offset(h
, vma
, addr
);
1201 chg
= region_chg(resv
, idx
, idx
+ 1);
1203 if (vma
->vm_flags
& VM_MAYSHARE
)
1206 return chg
< 0 ? chg
: 0;
1208 static void vma_commit_reservation(struct hstate
*h
,
1209 struct vm_area_struct
*vma
, unsigned long addr
)
1211 struct resv_map
*resv
;
1214 resv
= vma_resv_map(vma
);
1218 idx
= vma_hugecache_offset(h
, vma
, addr
);
1219 region_add(resv
, idx
, idx
+ 1);
1222 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1223 unsigned long addr
, int avoid_reserve
)
1225 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1226 struct hstate
*h
= hstate_vma(vma
);
1230 struct hugetlb_cgroup
*h_cg
;
1232 idx
= hstate_index(h
);
1234 * Processes that did not create the mapping will have no
1235 * reserves and will not have accounted against subpool
1236 * limit. Check that the subpool limit can be made before
1237 * satisfying the allocation MAP_NORESERVE mappings may also
1238 * need pages and subpool limit allocated allocated if no reserve
1241 chg
= vma_needs_reservation(h
, vma
, addr
);
1243 return ERR_PTR(-ENOMEM
);
1244 if (chg
|| avoid_reserve
)
1245 if (hugepage_subpool_get_pages(spool
, 1))
1246 return ERR_PTR(-ENOSPC
);
1248 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1250 if (chg
|| avoid_reserve
)
1251 hugepage_subpool_put_pages(spool
, 1);
1252 return ERR_PTR(-ENOSPC
);
1254 spin_lock(&hugetlb_lock
);
1255 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, chg
);
1257 spin_unlock(&hugetlb_lock
);
1258 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1260 hugetlb_cgroup_uncharge_cgroup(idx
,
1261 pages_per_huge_page(h
),
1263 if (chg
|| avoid_reserve
)
1264 hugepage_subpool_put_pages(spool
, 1);
1265 return ERR_PTR(-ENOSPC
);
1267 spin_lock(&hugetlb_lock
);
1268 list_move(&page
->lru
, &h
->hugepage_activelist
);
1271 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1272 spin_unlock(&hugetlb_lock
);
1274 set_page_private(page
, (unsigned long)spool
);
1276 vma_commit_reservation(h
, vma
, addr
);
1281 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1282 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1283 * where no ERR_VALUE is expected to be returned.
1285 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
1286 unsigned long addr
, int avoid_reserve
)
1288 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
1294 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1296 struct huge_bootmem_page
*m
;
1299 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1302 addr
= memblock_virt_alloc_try_nid_nopanic(
1303 huge_page_size(h
), huge_page_size(h
),
1304 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
1307 * Use the beginning of the huge page to store the
1308 * huge_bootmem_page struct (until gather_bootmem
1309 * puts them into the mem_map).
1318 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1319 /* Put them into a private list first because mem_map is not up yet */
1320 list_add(&m
->list
, &huge_boot_pages
);
1325 static void __init
prep_compound_huge_page(struct page
*page
, int order
)
1327 if (unlikely(order
> (MAX_ORDER
- 1)))
1328 prep_compound_gigantic_page(page
, order
);
1330 prep_compound_page(page
, order
);
1333 /* Put bootmem huge pages into the standard lists after mem_map is up */
1334 static void __init
gather_bootmem_prealloc(void)
1336 struct huge_bootmem_page
*m
;
1338 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1339 struct hstate
*h
= m
->hstate
;
1342 #ifdef CONFIG_HIGHMEM
1343 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1344 memblock_free_late(__pa(m
),
1345 sizeof(struct huge_bootmem_page
));
1347 page
= virt_to_page(m
);
1349 WARN_ON(page_count(page
) != 1);
1350 prep_compound_huge_page(page
, h
->order
);
1351 WARN_ON(PageReserved(page
));
1352 prep_new_huge_page(h
, page
, page_to_nid(page
));
1354 * If we had gigantic hugepages allocated at boot time, we need
1355 * to restore the 'stolen' pages to totalram_pages in order to
1356 * fix confusing memory reports from free(1) and another
1357 * side-effects, like CommitLimit going negative.
1359 if (h
->order
> (MAX_ORDER
- 1))
1360 adjust_managed_page_count(page
, 1 << h
->order
);
1364 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1368 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1369 if (h
->order
>= MAX_ORDER
) {
1370 if (!alloc_bootmem_huge_page(h
))
1372 } else if (!alloc_fresh_huge_page(h
,
1373 &node_states
[N_MEMORY
]))
1376 h
->max_huge_pages
= i
;
1379 static void __init
hugetlb_init_hstates(void)
1383 for_each_hstate(h
) {
1384 /* oversize hugepages were init'ed in early boot */
1385 if (h
->order
< MAX_ORDER
)
1386 hugetlb_hstate_alloc_pages(h
);
1390 static char * __init
memfmt(char *buf
, unsigned long n
)
1392 if (n
>= (1UL << 30))
1393 sprintf(buf
, "%lu GB", n
>> 30);
1394 else if (n
>= (1UL << 20))
1395 sprintf(buf
, "%lu MB", n
>> 20);
1397 sprintf(buf
, "%lu KB", n
>> 10);
1401 static void __init
report_hugepages(void)
1405 for_each_hstate(h
) {
1407 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1408 memfmt(buf
, huge_page_size(h
)),
1409 h
->free_huge_pages
);
1413 #ifdef CONFIG_HIGHMEM
1414 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1415 nodemask_t
*nodes_allowed
)
1419 if (h
->order
>= MAX_ORDER
)
1422 for_each_node_mask(i
, *nodes_allowed
) {
1423 struct page
*page
, *next
;
1424 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1425 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1426 if (count
>= h
->nr_huge_pages
)
1428 if (PageHighMem(page
))
1430 list_del(&page
->lru
);
1431 update_and_free_page(h
, page
);
1432 h
->free_huge_pages
--;
1433 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1438 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1439 nodemask_t
*nodes_allowed
)
1445 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1446 * balanced by operating on them in a round-robin fashion.
1447 * Returns 1 if an adjustment was made.
1449 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1454 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1457 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1458 if (h
->surplus_huge_pages_node
[node
])
1462 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1463 if (h
->surplus_huge_pages_node
[node
] <
1464 h
->nr_huge_pages_node
[node
])
1471 h
->surplus_huge_pages
+= delta
;
1472 h
->surplus_huge_pages_node
[node
] += delta
;
1476 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1477 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1478 nodemask_t
*nodes_allowed
)
1480 unsigned long min_count
, ret
;
1482 if (h
->order
>= MAX_ORDER
)
1483 return h
->max_huge_pages
;
1486 * Increase the pool size
1487 * First take pages out of surplus state. Then make up the
1488 * remaining difference by allocating fresh huge pages.
1490 * We might race with alloc_buddy_huge_page() here and be unable
1491 * to convert a surplus huge page to a normal huge page. That is
1492 * not critical, though, it just means the overall size of the
1493 * pool might be one hugepage larger than it needs to be, but
1494 * within all the constraints specified by the sysctls.
1496 spin_lock(&hugetlb_lock
);
1497 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1498 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1502 while (count
> persistent_huge_pages(h
)) {
1504 * If this allocation races such that we no longer need the
1505 * page, free_huge_page will handle it by freeing the page
1506 * and reducing the surplus.
1508 spin_unlock(&hugetlb_lock
);
1509 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1510 spin_lock(&hugetlb_lock
);
1514 /* Bail for signals. Probably ctrl-c from user */
1515 if (signal_pending(current
))
1520 * Decrease the pool size
1521 * First return free pages to the buddy allocator (being careful
1522 * to keep enough around to satisfy reservations). Then place
1523 * pages into surplus state as needed so the pool will shrink
1524 * to the desired size as pages become free.
1526 * By placing pages into the surplus state independent of the
1527 * overcommit value, we are allowing the surplus pool size to
1528 * exceed overcommit. There are few sane options here. Since
1529 * alloc_buddy_huge_page() is checking the global counter,
1530 * though, we'll note that we're not allowed to exceed surplus
1531 * and won't grow the pool anywhere else. Not until one of the
1532 * sysctls are changed, or the surplus pages go out of use.
1534 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1535 min_count
= max(count
, min_count
);
1536 try_to_free_low(h
, min_count
, nodes_allowed
);
1537 while (min_count
< persistent_huge_pages(h
)) {
1538 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1540 cond_resched_lock(&hugetlb_lock
);
1542 while (count
< persistent_huge_pages(h
)) {
1543 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1547 ret
= persistent_huge_pages(h
);
1548 spin_unlock(&hugetlb_lock
);
1552 #define HSTATE_ATTR_RO(_name) \
1553 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1555 #define HSTATE_ATTR(_name) \
1556 static struct kobj_attribute _name##_attr = \
1557 __ATTR(_name, 0644, _name##_show, _name##_store)
1559 static struct kobject
*hugepages_kobj
;
1560 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1562 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1564 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1568 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1569 if (hstate_kobjs
[i
] == kobj
) {
1571 *nidp
= NUMA_NO_NODE
;
1575 return kobj_to_node_hstate(kobj
, nidp
);
1578 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1579 struct kobj_attribute
*attr
, char *buf
)
1582 unsigned long nr_huge_pages
;
1585 h
= kobj_to_hstate(kobj
, &nid
);
1586 if (nid
== NUMA_NO_NODE
)
1587 nr_huge_pages
= h
->nr_huge_pages
;
1589 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1591 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1594 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1595 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1596 const char *buf
, size_t len
)
1600 unsigned long count
;
1602 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1604 err
= kstrtoul(buf
, 10, &count
);
1608 h
= kobj_to_hstate(kobj
, &nid
);
1609 if (h
->order
>= MAX_ORDER
) {
1614 if (nid
== NUMA_NO_NODE
) {
1616 * global hstate attribute
1618 if (!(obey_mempolicy
&&
1619 init_nodemask_of_mempolicy(nodes_allowed
))) {
1620 NODEMASK_FREE(nodes_allowed
);
1621 nodes_allowed
= &node_states
[N_MEMORY
];
1623 } else if (nodes_allowed
) {
1625 * per node hstate attribute: adjust count to global,
1626 * but restrict alloc/free to the specified node.
1628 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1629 init_nodemask_of_node(nodes_allowed
, nid
);
1631 nodes_allowed
= &node_states
[N_MEMORY
];
1633 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1635 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1636 NODEMASK_FREE(nodes_allowed
);
1640 NODEMASK_FREE(nodes_allowed
);
1644 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1645 struct kobj_attribute
*attr
, char *buf
)
1647 return nr_hugepages_show_common(kobj
, attr
, buf
);
1650 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1651 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1653 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1655 HSTATE_ATTR(nr_hugepages
);
1660 * hstate attribute for optionally mempolicy-based constraint on persistent
1661 * huge page alloc/free.
1663 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1664 struct kobj_attribute
*attr
, char *buf
)
1666 return nr_hugepages_show_common(kobj
, attr
, buf
);
1669 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1670 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1672 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1674 HSTATE_ATTR(nr_hugepages_mempolicy
);
1678 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1679 struct kobj_attribute
*attr
, char *buf
)
1681 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1682 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1685 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1686 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1689 unsigned long input
;
1690 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1692 if (h
->order
>= MAX_ORDER
)
1695 err
= kstrtoul(buf
, 10, &input
);
1699 spin_lock(&hugetlb_lock
);
1700 h
->nr_overcommit_huge_pages
= input
;
1701 spin_unlock(&hugetlb_lock
);
1705 HSTATE_ATTR(nr_overcommit_hugepages
);
1707 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1708 struct kobj_attribute
*attr
, char *buf
)
1711 unsigned long free_huge_pages
;
1714 h
= kobj_to_hstate(kobj
, &nid
);
1715 if (nid
== NUMA_NO_NODE
)
1716 free_huge_pages
= h
->free_huge_pages
;
1718 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1720 return sprintf(buf
, "%lu\n", free_huge_pages
);
1722 HSTATE_ATTR_RO(free_hugepages
);
1724 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1725 struct kobj_attribute
*attr
, char *buf
)
1727 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1728 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1730 HSTATE_ATTR_RO(resv_hugepages
);
1732 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1733 struct kobj_attribute
*attr
, char *buf
)
1736 unsigned long surplus_huge_pages
;
1739 h
= kobj_to_hstate(kobj
, &nid
);
1740 if (nid
== NUMA_NO_NODE
)
1741 surplus_huge_pages
= h
->surplus_huge_pages
;
1743 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1745 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1747 HSTATE_ATTR_RO(surplus_hugepages
);
1749 static struct attribute
*hstate_attrs
[] = {
1750 &nr_hugepages_attr
.attr
,
1751 &nr_overcommit_hugepages_attr
.attr
,
1752 &free_hugepages_attr
.attr
,
1753 &resv_hugepages_attr
.attr
,
1754 &surplus_hugepages_attr
.attr
,
1756 &nr_hugepages_mempolicy_attr
.attr
,
1761 static struct attribute_group hstate_attr_group
= {
1762 .attrs
= hstate_attrs
,
1765 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1766 struct kobject
**hstate_kobjs
,
1767 struct attribute_group
*hstate_attr_group
)
1770 int hi
= hstate_index(h
);
1772 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1773 if (!hstate_kobjs
[hi
])
1776 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1778 kobject_put(hstate_kobjs
[hi
]);
1783 static void __init
hugetlb_sysfs_init(void)
1788 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1789 if (!hugepages_kobj
)
1792 for_each_hstate(h
) {
1793 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1794 hstate_kobjs
, &hstate_attr_group
);
1796 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1803 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1804 * with node devices in node_devices[] using a parallel array. The array
1805 * index of a node device or _hstate == node id.
1806 * This is here to avoid any static dependency of the node device driver, in
1807 * the base kernel, on the hugetlb module.
1809 struct node_hstate
{
1810 struct kobject
*hugepages_kobj
;
1811 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1813 struct node_hstate node_hstates
[MAX_NUMNODES
];
1816 * A subset of global hstate attributes for node devices
1818 static struct attribute
*per_node_hstate_attrs
[] = {
1819 &nr_hugepages_attr
.attr
,
1820 &free_hugepages_attr
.attr
,
1821 &surplus_hugepages_attr
.attr
,
1825 static struct attribute_group per_node_hstate_attr_group
= {
1826 .attrs
= per_node_hstate_attrs
,
1830 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1831 * Returns node id via non-NULL nidp.
1833 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1837 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1838 struct node_hstate
*nhs
= &node_hstates
[nid
];
1840 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1841 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1853 * Unregister hstate attributes from a single node device.
1854 * No-op if no hstate attributes attached.
1856 static void hugetlb_unregister_node(struct node
*node
)
1859 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1861 if (!nhs
->hugepages_kobj
)
1862 return; /* no hstate attributes */
1864 for_each_hstate(h
) {
1865 int idx
= hstate_index(h
);
1866 if (nhs
->hstate_kobjs
[idx
]) {
1867 kobject_put(nhs
->hstate_kobjs
[idx
]);
1868 nhs
->hstate_kobjs
[idx
] = NULL
;
1872 kobject_put(nhs
->hugepages_kobj
);
1873 nhs
->hugepages_kobj
= NULL
;
1877 * hugetlb module exit: unregister hstate attributes from node devices
1880 static void hugetlb_unregister_all_nodes(void)
1885 * disable node device registrations.
1887 register_hugetlbfs_with_node(NULL
, NULL
);
1890 * remove hstate attributes from any nodes that have them.
1892 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1893 hugetlb_unregister_node(node_devices
[nid
]);
1897 * Register hstate attributes for a single node device.
1898 * No-op if attributes already registered.
1900 static void hugetlb_register_node(struct node
*node
)
1903 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1906 if (nhs
->hugepages_kobj
)
1907 return; /* already allocated */
1909 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1911 if (!nhs
->hugepages_kobj
)
1914 for_each_hstate(h
) {
1915 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1917 &per_node_hstate_attr_group
);
1919 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1920 h
->name
, node
->dev
.id
);
1921 hugetlb_unregister_node(node
);
1928 * hugetlb init time: register hstate attributes for all registered node
1929 * devices of nodes that have memory. All on-line nodes should have
1930 * registered their associated device by this time.
1932 static void hugetlb_register_all_nodes(void)
1936 for_each_node_state(nid
, N_MEMORY
) {
1937 struct node
*node
= node_devices
[nid
];
1938 if (node
->dev
.id
== nid
)
1939 hugetlb_register_node(node
);
1943 * Let the node device driver know we're here so it can
1944 * [un]register hstate attributes on node hotplug.
1946 register_hugetlbfs_with_node(hugetlb_register_node
,
1947 hugetlb_unregister_node
);
1949 #else /* !CONFIG_NUMA */
1951 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1959 static void hugetlb_unregister_all_nodes(void) { }
1961 static void hugetlb_register_all_nodes(void) { }
1965 static void __exit
hugetlb_exit(void)
1969 hugetlb_unregister_all_nodes();
1971 for_each_hstate(h
) {
1972 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1975 kobject_put(hugepages_kobj
);
1976 kfree(htlb_fault_mutex_table
);
1978 module_exit(hugetlb_exit
);
1980 static int __init
hugetlb_init(void)
1984 /* Some platform decide whether they support huge pages at boot
1985 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1986 * there is no such support
1988 if (HPAGE_SHIFT
== 0)
1991 if (!size_to_hstate(default_hstate_size
)) {
1992 default_hstate_size
= HPAGE_SIZE
;
1993 if (!size_to_hstate(default_hstate_size
))
1994 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1996 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1997 if (default_hstate_max_huge_pages
)
1998 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2000 hugetlb_init_hstates();
2001 gather_bootmem_prealloc();
2004 hugetlb_sysfs_init();
2005 hugetlb_register_all_nodes();
2006 hugetlb_cgroup_file_init();
2009 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2011 num_fault_mutexes
= 1;
2013 htlb_fault_mutex_table
=
2014 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2015 BUG_ON(!htlb_fault_mutex_table
);
2017 for (i
= 0; i
< num_fault_mutexes
; i
++)
2018 mutex_init(&htlb_fault_mutex_table
[i
]);
2021 module_init(hugetlb_init
);
2023 /* Should be called on processing a hugepagesz=... option */
2024 void __init
hugetlb_add_hstate(unsigned order
)
2029 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2030 pr_warning("hugepagesz= specified twice, ignoring\n");
2033 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2035 h
= &hstates
[hugetlb_max_hstate
++];
2037 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2038 h
->nr_huge_pages
= 0;
2039 h
->free_huge_pages
= 0;
2040 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2041 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2042 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2043 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
2044 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
2045 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2046 huge_page_size(h
)/1024);
2051 static int __init
hugetlb_nrpages_setup(char *s
)
2054 static unsigned long *last_mhp
;
2057 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2058 * so this hugepages= parameter goes to the "default hstate".
2060 if (!hugetlb_max_hstate
)
2061 mhp
= &default_hstate_max_huge_pages
;
2063 mhp
= &parsed_hstate
->max_huge_pages
;
2065 if (mhp
== last_mhp
) {
2066 pr_warning("hugepages= specified twice without "
2067 "interleaving hugepagesz=, ignoring\n");
2071 if (sscanf(s
, "%lu", mhp
) <= 0)
2075 * Global state is always initialized later in hugetlb_init.
2076 * But we need to allocate >= MAX_ORDER hstates here early to still
2077 * use the bootmem allocator.
2079 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2080 hugetlb_hstate_alloc_pages(parsed_hstate
);
2086 __setup("hugepages=", hugetlb_nrpages_setup
);
2088 static int __init
hugetlb_default_setup(char *s
)
2090 default_hstate_size
= memparse(s
, &s
);
2093 __setup("default_hugepagesz=", hugetlb_default_setup
);
2095 static unsigned int cpuset_mems_nr(unsigned int *array
)
2098 unsigned int nr
= 0;
2100 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2106 #ifdef CONFIG_SYSCTL
2107 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2108 struct ctl_table
*table
, int write
,
2109 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2111 struct hstate
*h
= &default_hstate
;
2115 tmp
= h
->max_huge_pages
;
2117 if (write
&& h
->order
>= MAX_ORDER
)
2121 table
->maxlen
= sizeof(unsigned long);
2122 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2127 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2128 GFP_KERNEL
| __GFP_NORETRY
);
2129 if (!(obey_mempolicy
&&
2130 init_nodemask_of_mempolicy(nodes_allowed
))) {
2131 NODEMASK_FREE(nodes_allowed
);
2132 nodes_allowed
= &node_states
[N_MEMORY
];
2134 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2136 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2137 NODEMASK_FREE(nodes_allowed
);
2143 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2144 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2147 return hugetlb_sysctl_handler_common(false, table
, write
,
2148 buffer
, length
, ppos
);
2152 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2153 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2155 return hugetlb_sysctl_handler_common(true, table
, write
,
2156 buffer
, length
, ppos
);
2158 #endif /* CONFIG_NUMA */
2160 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2161 void __user
*buffer
,
2162 size_t *length
, loff_t
*ppos
)
2164 struct hstate
*h
= &default_hstate
;
2168 tmp
= h
->nr_overcommit_huge_pages
;
2170 if (write
&& h
->order
>= MAX_ORDER
)
2174 table
->maxlen
= sizeof(unsigned long);
2175 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2180 spin_lock(&hugetlb_lock
);
2181 h
->nr_overcommit_huge_pages
= tmp
;
2182 spin_unlock(&hugetlb_lock
);
2188 #endif /* CONFIG_SYSCTL */
2190 void hugetlb_report_meminfo(struct seq_file
*m
)
2192 struct hstate
*h
= &default_hstate
;
2194 "HugePages_Total: %5lu\n"
2195 "HugePages_Free: %5lu\n"
2196 "HugePages_Rsvd: %5lu\n"
2197 "HugePages_Surp: %5lu\n"
2198 "Hugepagesize: %8lu kB\n",
2202 h
->surplus_huge_pages
,
2203 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2206 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2208 struct hstate
*h
= &default_hstate
;
2210 "Node %d HugePages_Total: %5u\n"
2211 "Node %d HugePages_Free: %5u\n"
2212 "Node %d HugePages_Surp: %5u\n",
2213 nid
, h
->nr_huge_pages_node
[nid
],
2214 nid
, h
->free_huge_pages_node
[nid
],
2215 nid
, h
->surplus_huge_pages_node
[nid
]);
2218 void hugetlb_show_meminfo(void)
2223 for_each_node_state(nid
, N_MEMORY
)
2225 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2227 h
->nr_huge_pages_node
[nid
],
2228 h
->free_huge_pages_node
[nid
],
2229 h
->surplus_huge_pages_node
[nid
],
2230 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2233 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2234 unsigned long hugetlb_total_pages(void)
2237 unsigned long nr_total_pages
= 0;
2240 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2241 return nr_total_pages
;
2244 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2248 spin_lock(&hugetlb_lock
);
2250 * When cpuset is configured, it breaks the strict hugetlb page
2251 * reservation as the accounting is done on a global variable. Such
2252 * reservation is completely rubbish in the presence of cpuset because
2253 * the reservation is not checked against page availability for the
2254 * current cpuset. Application can still potentially OOM'ed by kernel
2255 * with lack of free htlb page in cpuset that the task is in.
2256 * Attempt to enforce strict accounting with cpuset is almost
2257 * impossible (or too ugly) because cpuset is too fluid that
2258 * task or memory node can be dynamically moved between cpusets.
2260 * The change of semantics for shared hugetlb mapping with cpuset is
2261 * undesirable. However, in order to preserve some of the semantics,
2262 * we fall back to check against current free page availability as
2263 * a best attempt and hopefully to minimize the impact of changing
2264 * semantics that cpuset has.
2267 if (gather_surplus_pages(h
, delta
) < 0)
2270 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2271 return_unused_surplus_pages(h
, delta
);
2278 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2281 spin_unlock(&hugetlb_lock
);
2285 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2287 struct resv_map
*resv
= vma_resv_map(vma
);
2290 * This new VMA should share its siblings reservation map if present.
2291 * The VMA will only ever have a valid reservation map pointer where
2292 * it is being copied for another still existing VMA. As that VMA
2293 * has a reference to the reservation map it cannot disappear until
2294 * after this open call completes. It is therefore safe to take a
2295 * new reference here without additional locking.
2297 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2298 kref_get(&resv
->refs
);
2301 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2303 struct hstate
*h
= hstate_vma(vma
);
2304 struct resv_map
*resv
= vma_resv_map(vma
);
2305 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2306 unsigned long reserve
, start
, end
;
2308 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2311 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2312 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2314 reserve
= (end
- start
) - region_count(resv
, start
, end
);
2316 kref_put(&resv
->refs
, resv_map_release
);
2319 hugetlb_acct_memory(h
, -reserve
);
2320 hugepage_subpool_put_pages(spool
, reserve
);
2325 * We cannot handle pagefaults against hugetlb pages at all. They cause
2326 * handle_mm_fault() to try to instantiate regular-sized pages in the
2327 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2330 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2336 const struct vm_operations_struct hugetlb_vm_ops
= {
2337 .fault
= hugetlb_vm_op_fault
,
2338 .open
= hugetlb_vm_op_open
,
2339 .close
= hugetlb_vm_op_close
,
2342 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2348 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2349 vma
->vm_page_prot
)));
2351 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2352 vma
->vm_page_prot
));
2354 entry
= pte_mkyoung(entry
);
2355 entry
= pte_mkhuge(entry
);
2356 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2361 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2362 unsigned long address
, pte_t
*ptep
)
2366 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2367 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2368 update_mmu_cache(vma
, address
, ptep
);
2372 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2373 struct vm_area_struct
*vma
)
2375 pte_t
*src_pte
, *dst_pte
, entry
;
2376 struct page
*ptepage
;
2379 struct hstate
*h
= hstate_vma(vma
);
2380 unsigned long sz
= huge_page_size(h
);
2381 unsigned long mmun_start
; /* For mmu_notifiers */
2382 unsigned long mmun_end
; /* For mmu_notifiers */
2385 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2387 mmun_start
= vma
->vm_start
;
2388 mmun_end
= vma
->vm_end
;
2390 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
2392 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2393 spinlock_t
*src_ptl
, *dst_ptl
;
2394 src_pte
= huge_pte_offset(src
, addr
);
2397 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2403 /* If the pagetables are shared don't copy or take references */
2404 if (dst_pte
== src_pte
)
2407 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
2408 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
2409 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
2410 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2412 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2413 entry
= huge_ptep_get(src_pte
);
2414 ptepage
= pte_page(entry
);
2416 page_dup_rmap(ptepage
);
2417 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2419 spin_unlock(src_ptl
);
2420 spin_unlock(dst_ptl
);
2424 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
2429 static int is_hugetlb_entry_migration(pte_t pte
)
2433 if (huge_pte_none(pte
) || pte_present(pte
))
2435 swp
= pte_to_swp_entry(pte
);
2436 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2442 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2446 if (huge_pte_none(pte
) || pte_present(pte
))
2448 swp
= pte_to_swp_entry(pte
);
2449 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2455 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2456 unsigned long start
, unsigned long end
,
2457 struct page
*ref_page
)
2459 int force_flush
= 0;
2460 struct mm_struct
*mm
= vma
->vm_mm
;
2461 unsigned long address
;
2466 struct hstate
*h
= hstate_vma(vma
);
2467 unsigned long sz
= huge_page_size(h
);
2468 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2469 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2471 WARN_ON(!is_vm_hugetlb_page(vma
));
2472 BUG_ON(start
& ~huge_page_mask(h
));
2473 BUG_ON(end
& ~huge_page_mask(h
));
2475 tlb_start_vma(tlb
, vma
);
2476 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2478 for (address
= start
; address
< end
; address
+= sz
) {
2479 ptep
= huge_pte_offset(mm
, address
);
2483 ptl
= huge_pte_lock(h
, mm
, ptep
);
2484 if (huge_pmd_unshare(mm
, &address
, ptep
))
2487 pte
= huge_ptep_get(ptep
);
2488 if (huge_pte_none(pte
))
2492 * HWPoisoned hugepage is already unmapped and dropped reference
2494 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2495 huge_pte_clear(mm
, address
, ptep
);
2499 page
= pte_page(pte
);
2501 * If a reference page is supplied, it is because a specific
2502 * page is being unmapped, not a range. Ensure the page we
2503 * are about to unmap is the actual page of interest.
2506 if (page
!= ref_page
)
2510 * Mark the VMA as having unmapped its page so that
2511 * future faults in this VMA will fail rather than
2512 * looking like data was lost
2514 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2517 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2518 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2519 if (huge_pte_dirty(pte
))
2520 set_page_dirty(page
);
2522 page_remove_rmap(page
);
2523 force_flush
= !__tlb_remove_page(tlb
, page
);
2528 /* Bail out after unmapping reference page if supplied */
2537 * mmu_gather ran out of room to batch pages, we break out of
2538 * the PTE lock to avoid doing the potential expensive TLB invalidate
2539 * and page-free while holding it.
2544 if (address
< end
&& !ref_page
)
2547 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2548 tlb_end_vma(tlb
, vma
);
2551 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2552 struct vm_area_struct
*vma
, unsigned long start
,
2553 unsigned long end
, struct page
*ref_page
)
2555 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2558 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2559 * test will fail on a vma being torn down, and not grab a page table
2560 * on its way out. We're lucky that the flag has such an appropriate
2561 * name, and can in fact be safely cleared here. We could clear it
2562 * before the __unmap_hugepage_range above, but all that's necessary
2563 * is to clear it before releasing the i_mmap_mutex. This works
2564 * because in the context this is called, the VMA is about to be
2565 * destroyed and the i_mmap_mutex is held.
2567 vma
->vm_flags
&= ~VM_MAYSHARE
;
2570 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2571 unsigned long end
, struct page
*ref_page
)
2573 struct mm_struct
*mm
;
2574 struct mmu_gather tlb
;
2578 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2579 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2580 tlb_finish_mmu(&tlb
, start
, end
);
2584 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2585 * mappping it owns the reserve page for. The intention is to unmap the page
2586 * from other VMAs and let the children be SIGKILLed if they are faulting the
2589 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2590 struct page
*page
, unsigned long address
)
2592 struct hstate
*h
= hstate_vma(vma
);
2593 struct vm_area_struct
*iter_vma
;
2594 struct address_space
*mapping
;
2598 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2599 * from page cache lookup which is in HPAGE_SIZE units.
2601 address
= address
& huge_page_mask(h
);
2602 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2604 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2607 * Take the mapping lock for the duration of the table walk. As
2608 * this mapping should be shared between all the VMAs,
2609 * __unmap_hugepage_range() is called as the lock is already held
2611 mutex_lock(&mapping
->i_mmap_mutex
);
2612 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2613 /* Do not unmap the current VMA */
2614 if (iter_vma
== vma
)
2618 * Unmap the page from other VMAs without their own reserves.
2619 * They get marked to be SIGKILLed if they fault in these
2620 * areas. This is because a future no-page fault on this VMA
2621 * could insert a zeroed page instead of the data existing
2622 * from the time of fork. This would look like data corruption
2624 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2625 unmap_hugepage_range(iter_vma
, address
,
2626 address
+ huge_page_size(h
), page
);
2628 mutex_unlock(&mapping
->i_mmap_mutex
);
2634 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2635 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2636 * cannot race with other handlers or page migration.
2637 * Keep the pte_same checks anyway to make transition from the mutex easier.
2639 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2640 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2641 struct page
*pagecache_page
, spinlock_t
*ptl
)
2643 struct hstate
*h
= hstate_vma(vma
);
2644 struct page
*old_page
, *new_page
;
2645 int outside_reserve
= 0;
2646 unsigned long mmun_start
; /* For mmu_notifiers */
2647 unsigned long mmun_end
; /* For mmu_notifiers */
2649 old_page
= pte_page(pte
);
2652 /* If no-one else is actually using this page, avoid the copy
2653 * and just make the page writable */
2654 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2655 page_move_anon_rmap(old_page
, vma
, address
);
2656 set_huge_ptep_writable(vma
, address
, ptep
);
2661 * If the process that created a MAP_PRIVATE mapping is about to
2662 * perform a COW due to a shared page count, attempt to satisfy
2663 * the allocation without using the existing reserves. The pagecache
2664 * page is used to determine if the reserve at this address was
2665 * consumed or not. If reserves were used, a partial faulted mapping
2666 * at the time of fork() could consume its reserves on COW instead
2667 * of the full address range.
2669 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2670 old_page
!= pagecache_page
)
2671 outside_reserve
= 1;
2673 page_cache_get(old_page
);
2675 /* Drop page table lock as buddy allocator may be called */
2677 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2679 if (IS_ERR(new_page
)) {
2680 long err
= PTR_ERR(new_page
);
2681 page_cache_release(old_page
);
2684 * If a process owning a MAP_PRIVATE mapping fails to COW,
2685 * it is due to references held by a child and an insufficient
2686 * huge page pool. To guarantee the original mappers
2687 * reliability, unmap the page from child processes. The child
2688 * may get SIGKILLed if it later faults.
2690 if (outside_reserve
) {
2691 BUG_ON(huge_pte_none(pte
));
2692 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2693 BUG_ON(huge_pte_none(pte
));
2695 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2697 pte_same(huge_ptep_get(ptep
), pte
)))
2698 goto retry_avoidcopy
;
2700 * race occurs while re-acquiring page table
2701 * lock, and our job is done.
2708 /* Caller expects lock to be held */
2711 return VM_FAULT_OOM
;
2713 return VM_FAULT_SIGBUS
;
2717 * When the original hugepage is shared one, it does not have
2718 * anon_vma prepared.
2720 if (unlikely(anon_vma_prepare(vma
))) {
2721 page_cache_release(new_page
);
2722 page_cache_release(old_page
);
2723 /* Caller expects lock to be held */
2725 return VM_FAULT_OOM
;
2728 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2729 pages_per_huge_page(h
));
2730 __SetPageUptodate(new_page
);
2732 mmun_start
= address
& huge_page_mask(h
);
2733 mmun_end
= mmun_start
+ huge_page_size(h
);
2734 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2736 * Retake the page table lock to check for racing updates
2737 * before the page tables are altered
2740 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2741 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
2742 ClearPagePrivate(new_page
);
2745 huge_ptep_clear_flush(vma
, address
, ptep
);
2746 set_huge_pte_at(mm
, address
, ptep
,
2747 make_huge_pte(vma
, new_page
, 1));
2748 page_remove_rmap(old_page
);
2749 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2750 /* Make the old page be freed below */
2751 new_page
= old_page
;
2754 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2755 page_cache_release(new_page
);
2756 page_cache_release(old_page
);
2758 /* Caller expects lock to be held */
2763 /* Return the pagecache page at a given address within a VMA */
2764 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2765 struct vm_area_struct
*vma
, unsigned long address
)
2767 struct address_space
*mapping
;
2770 mapping
= vma
->vm_file
->f_mapping
;
2771 idx
= vma_hugecache_offset(h
, vma
, address
);
2773 return find_lock_page(mapping
, idx
);
2777 * Return whether there is a pagecache page to back given address within VMA.
2778 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2780 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2781 struct vm_area_struct
*vma
, unsigned long address
)
2783 struct address_space
*mapping
;
2787 mapping
= vma
->vm_file
->f_mapping
;
2788 idx
= vma_hugecache_offset(h
, vma
, address
);
2790 page
= find_get_page(mapping
, idx
);
2793 return page
!= NULL
;
2796 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2797 struct address_space
*mapping
, pgoff_t idx
,
2798 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2800 struct hstate
*h
= hstate_vma(vma
);
2801 int ret
= VM_FAULT_SIGBUS
;
2809 * Currently, we are forced to kill the process in the event the
2810 * original mapper has unmapped pages from the child due to a failed
2811 * COW. Warn that such a situation has occurred as it may not be obvious
2813 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2814 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2820 * Use page lock to guard against racing truncation
2821 * before we get page_table_lock.
2824 page
= find_lock_page(mapping
, idx
);
2826 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2829 page
= alloc_huge_page(vma
, address
, 0);
2831 ret
= PTR_ERR(page
);
2835 ret
= VM_FAULT_SIGBUS
;
2838 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2839 __SetPageUptodate(page
);
2841 if (vma
->vm_flags
& VM_MAYSHARE
) {
2843 struct inode
*inode
= mapping
->host
;
2845 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2852 ClearPagePrivate(page
);
2854 spin_lock(&inode
->i_lock
);
2855 inode
->i_blocks
+= blocks_per_huge_page(h
);
2856 spin_unlock(&inode
->i_lock
);
2859 if (unlikely(anon_vma_prepare(vma
))) {
2861 goto backout_unlocked
;
2867 * If memory error occurs between mmap() and fault, some process
2868 * don't have hwpoisoned swap entry for errored virtual address.
2869 * So we need to block hugepage fault by PG_hwpoison bit check.
2871 if (unlikely(PageHWPoison(page
))) {
2872 ret
= VM_FAULT_HWPOISON
|
2873 VM_FAULT_SET_HINDEX(hstate_index(h
));
2874 goto backout_unlocked
;
2879 * If we are going to COW a private mapping later, we examine the
2880 * pending reservations for this page now. This will ensure that
2881 * any allocations necessary to record that reservation occur outside
2884 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2885 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2887 goto backout_unlocked
;
2890 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
2892 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2897 if (!huge_pte_none(huge_ptep_get(ptep
)))
2901 ClearPagePrivate(page
);
2902 hugepage_add_new_anon_rmap(page
, vma
, address
);
2904 page_dup_rmap(page
);
2905 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2906 && (vma
->vm_flags
& VM_SHARED
)));
2907 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2909 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2910 /* Optimization, do the COW without a second fault */
2911 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
, ptl
);
2928 static u32
fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
2929 struct vm_area_struct
*vma
,
2930 struct address_space
*mapping
,
2931 pgoff_t idx
, unsigned long address
)
2933 unsigned long key
[2];
2936 if (vma
->vm_flags
& VM_SHARED
) {
2937 key
[0] = (unsigned long) mapping
;
2940 key
[0] = (unsigned long) mm
;
2941 key
[1] = address
>> huge_page_shift(h
);
2944 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
2946 return hash
& (num_fault_mutexes
- 1);
2950 * For uniprocesor systems we always use a single mutex, so just
2951 * return 0 and avoid the hashing overhead.
2953 static u32
fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
2954 struct vm_area_struct
*vma
,
2955 struct address_space
*mapping
,
2956 pgoff_t idx
, unsigned long address
)
2962 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2963 unsigned long address
, unsigned int flags
)
2970 struct page
*page
= NULL
;
2971 struct page
*pagecache_page
= NULL
;
2972 struct hstate
*h
= hstate_vma(vma
);
2973 struct address_space
*mapping
;
2975 address
&= huge_page_mask(h
);
2977 ptep
= huge_pte_offset(mm
, address
);
2979 entry
= huge_ptep_get(ptep
);
2980 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2981 migration_entry_wait_huge(vma
, mm
, ptep
);
2983 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2984 return VM_FAULT_HWPOISON_LARGE
|
2985 VM_FAULT_SET_HINDEX(hstate_index(h
));
2988 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2990 return VM_FAULT_OOM
;
2992 mapping
= vma
->vm_file
->f_mapping
;
2993 idx
= vma_hugecache_offset(h
, vma
, address
);
2996 * Serialize hugepage allocation and instantiation, so that we don't
2997 * get spurious allocation failures if two CPUs race to instantiate
2998 * the same page in the page cache.
3000 hash
= fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
3001 mutex_lock(&htlb_fault_mutex_table
[hash
]);
3003 entry
= huge_ptep_get(ptep
);
3004 if (huge_pte_none(entry
)) {
3005 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3012 * If we are going to COW the mapping later, we examine the pending
3013 * reservations for this page now. This will ensure that any
3014 * allocations necessary to record that reservation occur outside the
3015 * spinlock. For private mappings, we also lookup the pagecache
3016 * page now as it is used to determine if a reservation has been
3019 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3020 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3025 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3026 pagecache_page
= hugetlbfs_pagecache_page(h
,
3031 * hugetlb_cow() requires page locks of pte_page(entry) and
3032 * pagecache_page, so here we need take the former one
3033 * when page != pagecache_page or !pagecache_page.
3034 * Note that locking order is always pagecache_page -> page,
3035 * so no worry about deadlock.
3037 page
= pte_page(entry
);
3039 if (page
!= pagecache_page
)
3042 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
3044 /* Check for a racing update before calling hugetlb_cow */
3045 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3049 if (flags
& FAULT_FLAG_WRITE
) {
3050 if (!huge_pte_write(entry
)) {
3051 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
3052 pagecache_page
, ptl
);
3055 entry
= huge_pte_mkdirty(entry
);
3057 entry
= pte_mkyoung(entry
);
3058 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3059 flags
& FAULT_FLAG_WRITE
))
3060 update_mmu_cache(vma
, address
, ptep
);
3065 if (pagecache_page
) {
3066 unlock_page(pagecache_page
);
3067 put_page(pagecache_page
);
3069 if (page
!= pagecache_page
)
3074 mutex_unlock(&htlb_fault_mutex_table
[hash
]);
3078 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3079 struct page
**pages
, struct vm_area_struct
**vmas
,
3080 unsigned long *position
, unsigned long *nr_pages
,
3081 long i
, unsigned int flags
)
3083 unsigned long pfn_offset
;
3084 unsigned long vaddr
= *position
;
3085 unsigned long remainder
= *nr_pages
;
3086 struct hstate
*h
= hstate_vma(vma
);
3088 while (vaddr
< vma
->vm_end
&& remainder
) {
3090 spinlock_t
*ptl
= NULL
;
3095 * Some archs (sparc64, sh*) have multiple pte_ts to
3096 * each hugepage. We have to make sure we get the
3097 * first, for the page indexing below to work.
3099 * Note that page table lock is not held when pte is null.
3101 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
3103 ptl
= huge_pte_lock(h
, mm
, pte
);
3104 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
3107 * When coredumping, it suits get_dump_page if we just return
3108 * an error where there's an empty slot with no huge pagecache
3109 * to back it. This way, we avoid allocating a hugepage, and
3110 * the sparse dumpfile avoids allocating disk blocks, but its
3111 * huge holes still show up with zeroes where they need to be.
3113 if (absent
&& (flags
& FOLL_DUMP
) &&
3114 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
3122 * We need call hugetlb_fault for both hugepages under migration
3123 * (in which case hugetlb_fault waits for the migration,) and
3124 * hwpoisoned hugepages (in which case we need to prevent the
3125 * caller from accessing to them.) In order to do this, we use
3126 * here is_swap_pte instead of is_hugetlb_entry_migration and
3127 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3128 * both cases, and because we can't follow correct pages
3129 * directly from any kind of swap entries.
3131 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
3132 ((flags
& FOLL_WRITE
) &&
3133 !huge_pte_write(huge_ptep_get(pte
)))) {
3138 ret
= hugetlb_fault(mm
, vma
, vaddr
,
3139 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
3140 if (!(ret
& VM_FAULT_ERROR
))
3147 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
3148 page
= pte_page(huge_ptep_get(pte
));
3151 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3152 get_page_foll(pages
[i
]);
3162 if (vaddr
< vma
->vm_end
&& remainder
&&
3163 pfn_offset
< pages_per_huge_page(h
)) {
3165 * We use pfn_offset to avoid touching the pageframes
3166 * of this compound page.
3172 *nr_pages
= remainder
;
3175 return i
? i
: -EFAULT
;
3178 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3179 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3181 struct mm_struct
*mm
= vma
->vm_mm
;
3182 unsigned long start
= address
;
3185 struct hstate
*h
= hstate_vma(vma
);
3186 unsigned long pages
= 0;
3188 BUG_ON(address
>= end
);
3189 flush_cache_range(vma
, address
, end
);
3191 mmu_notifier_invalidate_range_start(mm
, start
, end
);
3192 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3193 for (; address
< end
; address
+= huge_page_size(h
)) {
3195 ptep
= huge_pte_offset(mm
, address
);
3198 ptl
= huge_pte_lock(h
, mm
, ptep
);
3199 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3204 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3205 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3206 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3207 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3208 set_huge_pte_at(mm
, address
, ptep
, pte
);
3214 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3215 * may have cleared our pud entry and done put_page on the page table:
3216 * once we release i_mmap_mutex, another task can do the final put_page
3217 * and that page table be reused and filled with junk.
3219 flush_tlb_range(vma
, start
, end
);
3220 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3221 mmu_notifier_invalidate_range_end(mm
, start
, end
);
3223 return pages
<< h
->order
;
3226 int hugetlb_reserve_pages(struct inode
*inode
,
3228 struct vm_area_struct
*vma
,
3229 vm_flags_t vm_flags
)
3232 struct hstate
*h
= hstate_inode(inode
);
3233 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3234 struct resv_map
*resv_map
;
3237 * Only apply hugepage reservation if asked. At fault time, an
3238 * attempt will be made for VM_NORESERVE to allocate a page
3239 * without using reserves
3241 if (vm_flags
& VM_NORESERVE
)
3245 * Shared mappings base their reservation on the number of pages that
3246 * are already allocated on behalf of the file. Private mappings need
3247 * to reserve the full area even if read-only as mprotect() may be
3248 * called to make the mapping read-write. Assume !vma is a shm mapping
3250 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
3251 resv_map
= inode_resv_map(inode
);
3253 chg
= region_chg(resv_map
, from
, to
);
3256 resv_map
= resv_map_alloc();
3262 set_vma_resv_map(vma
, resv_map
);
3263 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3271 /* There must be enough pages in the subpool for the mapping */
3272 if (hugepage_subpool_get_pages(spool
, chg
)) {
3278 * Check enough hugepages are available for the reservation.
3279 * Hand the pages back to the subpool if there are not
3281 ret
= hugetlb_acct_memory(h
, chg
);
3283 hugepage_subpool_put_pages(spool
, chg
);
3288 * Account for the reservations made. Shared mappings record regions
3289 * that have reservations as they are shared by multiple VMAs.
3290 * When the last VMA disappears, the region map says how much
3291 * the reservation was and the page cache tells how much of
3292 * the reservation was consumed. Private mappings are per-VMA and
3293 * only the consumed reservations are tracked. When the VMA
3294 * disappears, the original reservation is the VMA size and the
3295 * consumed reservations are stored in the map. Hence, nothing
3296 * else has to be done for private mappings here
3298 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3299 region_add(resv_map
, from
, to
);
3302 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3303 kref_put(&resv_map
->refs
, resv_map_release
);
3307 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3309 struct hstate
*h
= hstate_inode(inode
);
3310 struct resv_map
*resv_map
= inode_resv_map(inode
);
3312 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3315 chg
= region_truncate(resv_map
, offset
);
3316 spin_lock(&inode
->i_lock
);
3317 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3318 spin_unlock(&inode
->i_lock
);
3320 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3321 hugetlb_acct_memory(h
, -(chg
- freed
));
3324 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3325 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3326 struct vm_area_struct
*vma
,
3327 unsigned long addr
, pgoff_t idx
)
3329 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3331 unsigned long sbase
= saddr
& PUD_MASK
;
3332 unsigned long s_end
= sbase
+ PUD_SIZE
;
3334 /* Allow segments to share if only one is marked locked */
3335 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3336 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3339 * match the virtual addresses, permission and the alignment of the
3342 if (pmd_index(addr
) != pmd_index(saddr
) ||
3343 vm_flags
!= svm_flags
||
3344 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3350 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3352 unsigned long base
= addr
& PUD_MASK
;
3353 unsigned long end
= base
+ PUD_SIZE
;
3356 * check on proper vm_flags and page table alignment
3358 if (vma
->vm_flags
& VM_MAYSHARE
&&
3359 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3365 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3366 * and returns the corresponding pte. While this is not necessary for the
3367 * !shared pmd case because we can allocate the pmd later as well, it makes the
3368 * code much cleaner. pmd allocation is essential for the shared case because
3369 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3370 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3371 * bad pmd for sharing.
3373 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3375 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3376 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3377 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3379 struct vm_area_struct
*svma
;
3380 unsigned long saddr
;
3385 if (!vma_shareable(vma
, addr
))
3386 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3388 mutex_lock(&mapping
->i_mmap_mutex
);
3389 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3393 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3395 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3397 get_page(virt_to_page(spte
));
3406 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, spte
);
3409 pud_populate(mm
, pud
,
3410 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3412 put_page(virt_to_page(spte
));
3415 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3416 mutex_unlock(&mapping
->i_mmap_mutex
);
3421 * unmap huge page backed by shared pte.
3423 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3424 * indicated by page_count > 1, unmap is achieved by clearing pud and
3425 * decrementing the ref count. If count == 1, the pte page is not shared.
3427 * called with page table lock held.
3429 * returns: 1 successfully unmapped a shared pte page
3430 * 0 the underlying pte page is not shared, or it is the last user
3432 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3434 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3435 pud_t
*pud
= pud_offset(pgd
, *addr
);
3437 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3438 if (page_count(virt_to_page(ptep
)) == 1)
3442 put_page(virt_to_page(ptep
));
3443 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3446 #define want_pmd_share() (1)
3447 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3448 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3452 #define want_pmd_share() (0)
3453 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3455 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3456 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3457 unsigned long addr
, unsigned long sz
)
3463 pgd
= pgd_offset(mm
, addr
);
3464 pud
= pud_alloc(mm
, pgd
, addr
);
3466 if (sz
== PUD_SIZE
) {
3469 BUG_ON(sz
!= PMD_SIZE
);
3470 if (want_pmd_share() && pud_none(*pud
))
3471 pte
= huge_pmd_share(mm
, addr
, pud
);
3473 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3476 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3481 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3487 pgd
= pgd_offset(mm
, addr
);
3488 if (pgd_present(*pgd
)) {
3489 pud
= pud_offset(pgd
, addr
);
3490 if (pud_present(*pud
)) {
3492 return (pte_t
*)pud
;
3493 pmd
= pmd_offset(pud
, addr
);
3496 return (pte_t
*) pmd
;
3500 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3501 pmd_t
*pmd
, int write
)
3505 page
= pte_page(*(pte_t
*)pmd
);
3507 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3512 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3513 pud_t
*pud
, int write
)
3517 page
= pte_page(*(pte_t
*)pud
);
3519 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3523 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3525 /* Can be overriden by architectures */
3526 struct page
* __weak
3527 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3528 pud_t
*pud
, int write
)
3534 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3536 #ifdef CONFIG_MEMORY_FAILURE
3538 /* Should be called in hugetlb_lock */
3539 static int is_hugepage_on_freelist(struct page
*hpage
)
3543 struct hstate
*h
= page_hstate(hpage
);
3544 int nid
= page_to_nid(hpage
);
3546 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3553 * This function is called from memory failure code.
3554 * Assume the caller holds page lock of the head page.
3556 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3558 struct hstate
*h
= page_hstate(hpage
);
3559 int nid
= page_to_nid(hpage
);
3562 spin_lock(&hugetlb_lock
);
3563 if (is_hugepage_on_freelist(hpage
)) {
3565 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3566 * but dangling hpage->lru can trigger list-debug warnings
3567 * (this happens when we call unpoison_memory() on it),
3568 * so let it point to itself with list_del_init().
3570 list_del_init(&hpage
->lru
);
3571 set_page_refcounted(hpage
);
3572 h
->free_huge_pages
--;
3573 h
->free_huge_pages_node
[nid
]--;
3576 spin_unlock(&hugetlb_lock
);
3581 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
3583 VM_BUG_ON_PAGE(!PageHead(page
), page
);
3584 if (!get_page_unless_zero(page
))
3586 spin_lock(&hugetlb_lock
);
3587 list_move_tail(&page
->lru
, list
);
3588 spin_unlock(&hugetlb_lock
);
3592 void putback_active_hugepage(struct page
*page
)
3594 VM_BUG_ON_PAGE(!PageHead(page
), page
);
3595 spin_lock(&hugetlb_lock
);
3596 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
3597 spin_unlock(&hugetlb_lock
);
3601 bool is_hugepage_active(struct page
*page
)
3603 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
3605 * This function can be called for a tail page because the caller,
3606 * scan_movable_pages, scans through a given pfn-range which typically
3607 * covers one memory block. In systems using gigantic hugepage (1GB
3608 * for x86_64,) a hugepage is larger than a memory block, and we don't
3609 * support migrating such large hugepages for now, so return false
3610 * when called for tail pages.
3615 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3616 * so we should return false for them.
3618 if (unlikely(PageHWPoison(page
)))
3620 return page_count(page
) > 0;