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))
1179 * Determine if the huge page at addr within the vma has an associated
1180 * reservation. Where it does not we will need to logically increase
1181 * reservation and actually increase subpool usage before an allocation
1182 * can occur. Where any new reservation would be required the
1183 * reservation change is prepared, but not committed. Once the page
1184 * has been allocated from the subpool and instantiated the change should
1185 * be committed via vma_commit_reservation. No action is required on
1188 static long vma_needs_reservation(struct hstate
*h
,
1189 struct vm_area_struct
*vma
, unsigned long addr
)
1191 struct resv_map
*resv
;
1195 resv
= vma_resv_map(vma
);
1199 idx
= vma_hugecache_offset(h
, vma
, addr
);
1200 chg
= region_chg(resv
, idx
, idx
+ 1);
1202 if (vma
->vm_flags
& VM_MAYSHARE
)
1205 return chg
< 0 ? chg
: 0;
1207 static void vma_commit_reservation(struct hstate
*h
,
1208 struct vm_area_struct
*vma
, unsigned long addr
)
1210 struct resv_map
*resv
;
1213 resv
= vma_resv_map(vma
);
1217 idx
= vma_hugecache_offset(h
, vma
, addr
);
1218 region_add(resv
, idx
, idx
+ 1);
1221 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1222 unsigned long addr
, int avoid_reserve
)
1224 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1225 struct hstate
*h
= hstate_vma(vma
);
1229 struct hugetlb_cgroup
*h_cg
;
1231 idx
= hstate_index(h
);
1233 * Processes that did not create the mapping will have no
1234 * reserves and will not have accounted against subpool
1235 * limit. Check that the subpool limit can be made before
1236 * satisfying the allocation MAP_NORESERVE mappings may also
1237 * need pages and subpool limit allocated allocated if no reserve
1240 chg
= vma_needs_reservation(h
, vma
, addr
);
1242 return ERR_PTR(-ENOMEM
);
1243 if (chg
|| avoid_reserve
)
1244 if (hugepage_subpool_get_pages(spool
, 1))
1245 return ERR_PTR(-ENOSPC
);
1247 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1249 if (chg
|| avoid_reserve
)
1250 hugepage_subpool_put_pages(spool
, 1);
1251 return ERR_PTR(-ENOSPC
);
1253 spin_lock(&hugetlb_lock
);
1254 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, chg
);
1256 spin_unlock(&hugetlb_lock
);
1257 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1259 hugetlb_cgroup_uncharge_cgroup(idx
,
1260 pages_per_huge_page(h
),
1262 if (chg
|| avoid_reserve
)
1263 hugepage_subpool_put_pages(spool
, 1);
1264 return ERR_PTR(-ENOSPC
);
1266 spin_lock(&hugetlb_lock
);
1267 list_move(&page
->lru
, &h
->hugepage_activelist
);
1270 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1271 spin_unlock(&hugetlb_lock
);
1273 set_page_private(page
, (unsigned long)spool
);
1275 vma_commit_reservation(h
, vma
, addr
);
1280 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1281 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1282 * where no ERR_VALUE is expected to be returned.
1284 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
1285 unsigned long addr
, int avoid_reserve
)
1287 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
1293 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1295 struct huge_bootmem_page
*m
;
1298 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1301 addr
= memblock_virt_alloc_try_nid_nopanic(
1302 huge_page_size(h
), huge_page_size(h
),
1303 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
1306 * Use the beginning of the huge page to store the
1307 * huge_bootmem_page struct (until gather_bootmem
1308 * puts them into the mem_map).
1317 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1318 /* Put them into a private list first because mem_map is not up yet */
1319 list_add(&m
->list
, &huge_boot_pages
);
1324 static void __init
prep_compound_huge_page(struct page
*page
, int order
)
1326 if (unlikely(order
> (MAX_ORDER
- 1)))
1327 prep_compound_gigantic_page(page
, order
);
1329 prep_compound_page(page
, order
);
1332 /* Put bootmem huge pages into the standard lists after mem_map is up */
1333 static void __init
gather_bootmem_prealloc(void)
1335 struct huge_bootmem_page
*m
;
1337 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1338 struct hstate
*h
= m
->hstate
;
1341 #ifdef CONFIG_HIGHMEM
1342 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1343 memblock_free_late(__pa(m
),
1344 sizeof(struct huge_bootmem_page
));
1346 page
= virt_to_page(m
);
1348 WARN_ON(page_count(page
) != 1);
1349 prep_compound_huge_page(page
, h
->order
);
1350 WARN_ON(PageReserved(page
));
1351 prep_new_huge_page(h
, page
, page_to_nid(page
));
1353 * If we had gigantic hugepages allocated at boot time, we need
1354 * to restore the 'stolen' pages to totalram_pages in order to
1355 * fix confusing memory reports from free(1) and another
1356 * side-effects, like CommitLimit going negative.
1358 if (h
->order
> (MAX_ORDER
- 1))
1359 adjust_managed_page_count(page
, 1 << h
->order
);
1363 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1367 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1368 if (h
->order
>= MAX_ORDER
) {
1369 if (!alloc_bootmem_huge_page(h
))
1371 } else if (!alloc_fresh_huge_page(h
,
1372 &node_states
[N_MEMORY
]))
1375 h
->max_huge_pages
= i
;
1378 static void __init
hugetlb_init_hstates(void)
1382 for_each_hstate(h
) {
1383 /* oversize hugepages were init'ed in early boot */
1384 if (h
->order
< MAX_ORDER
)
1385 hugetlb_hstate_alloc_pages(h
);
1389 static char * __init
memfmt(char *buf
, unsigned long n
)
1391 if (n
>= (1UL << 30))
1392 sprintf(buf
, "%lu GB", n
>> 30);
1393 else if (n
>= (1UL << 20))
1394 sprintf(buf
, "%lu MB", n
>> 20);
1396 sprintf(buf
, "%lu KB", n
>> 10);
1400 static void __init
report_hugepages(void)
1404 for_each_hstate(h
) {
1406 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1407 memfmt(buf
, huge_page_size(h
)),
1408 h
->free_huge_pages
);
1412 #ifdef CONFIG_HIGHMEM
1413 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1414 nodemask_t
*nodes_allowed
)
1418 if (h
->order
>= MAX_ORDER
)
1421 for_each_node_mask(i
, *nodes_allowed
) {
1422 struct page
*page
, *next
;
1423 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1424 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1425 if (count
>= h
->nr_huge_pages
)
1427 if (PageHighMem(page
))
1429 list_del(&page
->lru
);
1430 update_and_free_page(h
, page
);
1431 h
->free_huge_pages
--;
1432 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1437 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1438 nodemask_t
*nodes_allowed
)
1444 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1445 * balanced by operating on them in a round-robin fashion.
1446 * Returns 1 if an adjustment was made.
1448 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1453 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1456 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1457 if (h
->surplus_huge_pages_node
[node
])
1461 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1462 if (h
->surplus_huge_pages_node
[node
] <
1463 h
->nr_huge_pages_node
[node
])
1470 h
->surplus_huge_pages
+= delta
;
1471 h
->surplus_huge_pages_node
[node
] += delta
;
1475 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1476 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1477 nodemask_t
*nodes_allowed
)
1479 unsigned long min_count
, ret
;
1481 if (h
->order
>= MAX_ORDER
)
1482 return h
->max_huge_pages
;
1485 * Increase the pool size
1486 * First take pages out of surplus state. Then make up the
1487 * remaining difference by allocating fresh huge pages.
1489 * We might race with alloc_buddy_huge_page() here and be unable
1490 * to convert a surplus huge page to a normal huge page. That is
1491 * not critical, though, it just means the overall size of the
1492 * pool might be one hugepage larger than it needs to be, but
1493 * within all the constraints specified by the sysctls.
1495 spin_lock(&hugetlb_lock
);
1496 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1497 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1501 while (count
> persistent_huge_pages(h
)) {
1503 * If this allocation races such that we no longer need the
1504 * page, free_huge_page will handle it by freeing the page
1505 * and reducing the surplus.
1507 spin_unlock(&hugetlb_lock
);
1508 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1509 spin_lock(&hugetlb_lock
);
1513 /* Bail for signals. Probably ctrl-c from user */
1514 if (signal_pending(current
))
1519 * Decrease the pool size
1520 * First return free pages to the buddy allocator (being careful
1521 * to keep enough around to satisfy reservations). Then place
1522 * pages into surplus state as needed so the pool will shrink
1523 * to the desired size as pages become free.
1525 * By placing pages into the surplus state independent of the
1526 * overcommit value, we are allowing the surplus pool size to
1527 * exceed overcommit. There are few sane options here. Since
1528 * alloc_buddy_huge_page() is checking the global counter,
1529 * though, we'll note that we're not allowed to exceed surplus
1530 * and won't grow the pool anywhere else. Not until one of the
1531 * sysctls are changed, or the surplus pages go out of use.
1533 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1534 min_count
= max(count
, min_count
);
1535 try_to_free_low(h
, min_count
, nodes_allowed
);
1536 while (min_count
< persistent_huge_pages(h
)) {
1537 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1540 while (count
< persistent_huge_pages(h
)) {
1541 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1545 ret
= persistent_huge_pages(h
);
1546 spin_unlock(&hugetlb_lock
);
1550 #define HSTATE_ATTR_RO(_name) \
1551 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1553 #define HSTATE_ATTR(_name) \
1554 static struct kobj_attribute _name##_attr = \
1555 __ATTR(_name, 0644, _name##_show, _name##_store)
1557 static struct kobject
*hugepages_kobj
;
1558 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1560 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1562 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1566 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1567 if (hstate_kobjs
[i
] == kobj
) {
1569 *nidp
= NUMA_NO_NODE
;
1573 return kobj_to_node_hstate(kobj
, nidp
);
1576 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1577 struct kobj_attribute
*attr
, char *buf
)
1580 unsigned long nr_huge_pages
;
1583 h
= kobj_to_hstate(kobj
, &nid
);
1584 if (nid
== NUMA_NO_NODE
)
1585 nr_huge_pages
= h
->nr_huge_pages
;
1587 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1589 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1592 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1593 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1594 const char *buf
, size_t len
)
1598 unsigned long count
;
1600 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1602 err
= kstrtoul(buf
, 10, &count
);
1606 h
= kobj_to_hstate(kobj
, &nid
);
1607 if (h
->order
>= MAX_ORDER
) {
1612 if (nid
== NUMA_NO_NODE
) {
1614 * global hstate attribute
1616 if (!(obey_mempolicy
&&
1617 init_nodemask_of_mempolicy(nodes_allowed
))) {
1618 NODEMASK_FREE(nodes_allowed
);
1619 nodes_allowed
= &node_states
[N_MEMORY
];
1621 } else if (nodes_allowed
) {
1623 * per node hstate attribute: adjust count to global,
1624 * but restrict alloc/free to the specified node.
1626 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1627 init_nodemask_of_node(nodes_allowed
, nid
);
1629 nodes_allowed
= &node_states
[N_MEMORY
];
1631 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1633 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1634 NODEMASK_FREE(nodes_allowed
);
1638 NODEMASK_FREE(nodes_allowed
);
1642 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1643 struct kobj_attribute
*attr
, char *buf
)
1645 return nr_hugepages_show_common(kobj
, attr
, buf
);
1648 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1649 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1651 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1653 HSTATE_ATTR(nr_hugepages
);
1658 * hstate attribute for optionally mempolicy-based constraint on persistent
1659 * huge page alloc/free.
1661 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1662 struct kobj_attribute
*attr
, char *buf
)
1664 return nr_hugepages_show_common(kobj
, attr
, buf
);
1667 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1668 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1670 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1672 HSTATE_ATTR(nr_hugepages_mempolicy
);
1676 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1677 struct kobj_attribute
*attr
, char *buf
)
1679 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1680 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1683 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1684 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1687 unsigned long input
;
1688 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1690 if (h
->order
>= MAX_ORDER
)
1693 err
= kstrtoul(buf
, 10, &input
);
1697 spin_lock(&hugetlb_lock
);
1698 h
->nr_overcommit_huge_pages
= input
;
1699 spin_unlock(&hugetlb_lock
);
1703 HSTATE_ATTR(nr_overcommit_hugepages
);
1705 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1706 struct kobj_attribute
*attr
, char *buf
)
1709 unsigned long free_huge_pages
;
1712 h
= kobj_to_hstate(kobj
, &nid
);
1713 if (nid
== NUMA_NO_NODE
)
1714 free_huge_pages
= h
->free_huge_pages
;
1716 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1718 return sprintf(buf
, "%lu\n", free_huge_pages
);
1720 HSTATE_ATTR_RO(free_hugepages
);
1722 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1723 struct kobj_attribute
*attr
, char *buf
)
1725 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1726 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1728 HSTATE_ATTR_RO(resv_hugepages
);
1730 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1731 struct kobj_attribute
*attr
, char *buf
)
1734 unsigned long surplus_huge_pages
;
1737 h
= kobj_to_hstate(kobj
, &nid
);
1738 if (nid
== NUMA_NO_NODE
)
1739 surplus_huge_pages
= h
->surplus_huge_pages
;
1741 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1743 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1745 HSTATE_ATTR_RO(surplus_hugepages
);
1747 static struct attribute
*hstate_attrs
[] = {
1748 &nr_hugepages_attr
.attr
,
1749 &nr_overcommit_hugepages_attr
.attr
,
1750 &free_hugepages_attr
.attr
,
1751 &resv_hugepages_attr
.attr
,
1752 &surplus_hugepages_attr
.attr
,
1754 &nr_hugepages_mempolicy_attr
.attr
,
1759 static struct attribute_group hstate_attr_group
= {
1760 .attrs
= hstate_attrs
,
1763 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1764 struct kobject
**hstate_kobjs
,
1765 struct attribute_group
*hstate_attr_group
)
1768 int hi
= hstate_index(h
);
1770 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1771 if (!hstate_kobjs
[hi
])
1774 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1776 kobject_put(hstate_kobjs
[hi
]);
1781 static void __init
hugetlb_sysfs_init(void)
1786 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1787 if (!hugepages_kobj
)
1790 for_each_hstate(h
) {
1791 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1792 hstate_kobjs
, &hstate_attr_group
);
1794 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1801 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1802 * with node devices in node_devices[] using a parallel array. The array
1803 * index of a node device or _hstate == node id.
1804 * This is here to avoid any static dependency of the node device driver, in
1805 * the base kernel, on the hugetlb module.
1807 struct node_hstate
{
1808 struct kobject
*hugepages_kobj
;
1809 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1811 struct node_hstate node_hstates
[MAX_NUMNODES
];
1814 * A subset of global hstate attributes for node devices
1816 static struct attribute
*per_node_hstate_attrs
[] = {
1817 &nr_hugepages_attr
.attr
,
1818 &free_hugepages_attr
.attr
,
1819 &surplus_hugepages_attr
.attr
,
1823 static struct attribute_group per_node_hstate_attr_group
= {
1824 .attrs
= per_node_hstate_attrs
,
1828 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1829 * Returns node id via non-NULL nidp.
1831 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1835 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1836 struct node_hstate
*nhs
= &node_hstates
[nid
];
1838 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1839 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1851 * Unregister hstate attributes from a single node device.
1852 * No-op if no hstate attributes attached.
1854 static void hugetlb_unregister_node(struct node
*node
)
1857 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1859 if (!nhs
->hugepages_kobj
)
1860 return; /* no hstate attributes */
1862 for_each_hstate(h
) {
1863 int idx
= hstate_index(h
);
1864 if (nhs
->hstate_kobjs
[idx
]) {
1865 kobject_put(nhs
->hstate_kobjs
[idx
]);
1866 nhs
->hstate_kobjs
[idx
] = NULL
;
1870 kobject_put(nhs
->hugepages_kobj
);
1871 nhs
->hugepages_kobj
= NULL
;
1875 * hugetlb module exit: unregister hstate attributes from node devices
1878 static void hugetlb_unregister_all_nodes(void)
1883 * disable node device registrations.
1885 register_hugetlbfs_with_node(NULL
, NULL
);
1888 * remove hstate attributes from any nodes that have them.
1890 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1891 hugetlb_unregister_node(node_devices
[nid
]);
1895 * Register hstate attributes for a single node device.
1896 * No-op if attributes already registered.
1898 static void hugetlb_register_node(struct node
*node
)
1901 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1904 if (nhs
->hugepages_kobj
)
1905 return; /* already allocated */
1907 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1909 if (!nhs
->hugepages_kobj
)
1912 for_each_hstate(h
) {
1913 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1915 &per_node_hstate_attr_group
);
1917 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1918 h
->name
, node
->dev
.id
);
1919 hugetlb_unregister_node(node
);
1926 * hugetlb init time: register hstate attributes for all registered node
1927 * devices of nodes that have memory. All on-line nodes should have
1928 * registered their associated device by this time.
1930 static void hugetlb_register_all_nodes(void)
1934 for_each_node_state(nid
, N_MEMORY
) {
1935 struct node
*node
= node_devices
[nid
];
1936 if (node
->dev
.id
== nid
)
1937 hugetlb_register_node(node
);
1941 * Let the node device driver know we're here so it can
1942 * [un]register hstate attributes on node hotplug.
1944 register_hugetlbfs_with_node(hugetlb_register_node
,
1945 hugetlb_unregister_node
);
1947 #else /* !CONFIG_NUMA */
1949 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1957 static void hugetlb_unregister_all_nodes(void) { }
1959 static void hugetlb_register_all_nodes(void) { }
1963 static void __exit
hugetlb_exit(void)
1967 hugetlb_unregister_all_nodes();
1969 for_each_hstate(h
) {
1970 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1973 kobject_put(hugepages_kobj
);
1974 kfree(htlb_fault_mutex_table
);
1976 module_exit(hugetlb_exit
);
1978 static int __init
hugetlb_init(void)
1982 /* Some platform decide whether they support huge pages at boot
1983 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1984 * there is no such support
1986 if (HPAGE_SHIFT
== 0)
1989 if (!size_to_hstate(default_hstate_size
)) {
1990 default_hstate_size
= HPAGE_SIZE
;
1991 if (!size_to_hstate(default_hstate_size
))
1992 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1994 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1995 if (default_hstate_max_huge_pages
)
1996 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1998 hugetlb_init_hstates();
1999 gather_bootmem_prealloc();
2002 hugetlb_sysfs_init();
2003 hugetlb_register_all_nodes();
2004 hugetlb_cgroup_file_init();
2007 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2009 num_fault_mutexes
= 1;
2011 htlb_fault_mutex_table
=
2012 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2013 BUG_ON(!htlb_fault_mutex_table
);
2015 for (i
= 0; i
< num_fault_mutexes
; i
++)
2016 mutex_init(&htlb_fault_mutex_table
[i
]);
2019 module_init(hugetlb_init
);
2021 /* Should be called on processing a hugepagesz=... option */
2022 void __init
hugetlb_add_hstate(unsigned order
)
2027 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2028 pr_warning("hugepagesz= specified twice, ignoring\n");
2031 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2033 h
= &hstates
[hugetlb_max_hstate
++];
2035 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2036 h
->nr_huge_pages
= 0;
2037 h
->free_huge_pages
= 0;
2038 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2039 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2040 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2041 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
2042 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
2043 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2044 huge_page_size(h
)/1024);
2049 static int __init
hugetlb_nrpages_setup(char *s
)
2052 static unsigned long *last_mhp
;
2055 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2056 * so this hugepages= parameter goes to the "default hstate".
2058 if (!hugetlb_max_hstate
)
2059 mhp
= &default_hstate_max_huge_pages
;
2061 mhp
= &parsed_hstate
->max_huge_pages
;
2063 if (mhp
== last_mhp
) {
2064 pr_warning("hugepages= specified twice without "
2065 "interleaving hugepagesz=, ignoring\n");
2069 if (sscanf(s
, "%lu", mhp
) <= 0)
2073 * Global state is always initialized later in hugetlb_init.
2074 * But we need to allocate >= MAX_ORDER hstates here early to still
2075 * use the bootmem allocator.
2077 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2078 hugetlb_hstate_alloc_pages(parsed_hstate
);
2084 __setup("hugepages=", hugetlb_nrpages_setup
);
2086 static int __init
hugetlb_default_setup(char *s
)
2088 default_hstate_size
= memparse(s
, &s
);
2091 __setup("default_hugepagesz=", hugetlb_default_setup
);
2093 static unsigned int cpuset_mems_nr(unsigned int *array
)
2096 unsigned int nr
= 0;
2098 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2104 #ifdef CONFIG_SYSCTL
2105 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2106 struct ctl_table
*table
, int write
,
2107 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2109 struct hstate
*h
= &default_hstate
;
2113 tmp
= h
->max_huge_pages
;
2115 if (write
&& h
->order
>= MAX_ORDER
)
2119 table
->maxlen
= sizeof(unsigned long);
2120 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2125 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2126 GFP_KERNEL
| __GFP_NORETRY
);
2127 if (!(obey_mempolicy
&&
2128 init_nodemask_of_mempolicy(nodes_allowed
))) {
2129 NODEMASK_FREE(nodes_allowed
);
2130 nodes_allowed
= &node_states
[N_MEMORY
];
2132 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2134 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2135 NODEMASK_FREE(nodes_allowed
);
2141 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2142 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2145 return hugetlb_sysctl_handler_common(false, table
, write
,
2146 buffer
, length
, ppos
);
2150 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2151 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2153 return hugetlb_sysctl_handler_common(true, table
, write
,
2154 buffer
, length
, ppos
);
2156 #endif /* CONFIG_NUMA */
2158 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2159 void __user
*buffer
,
2160 size_t *length
, loff_t
*ppos
)
2162 struct hstate
*h
= &default_hstate
;
2166 tmp
= h
->nr_overcommit_huge_pages
;
2168 if (write
&& h
->order
>= MAX_ORDER
)
2172 table
->maxlen
= sizeof(unsigned long);
2173 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2178 spin_lock(&hugetlb_lock
);
2179 h
->nr_overcommit_huge_pages
= tmp
;
2180 spin_unlock(&hugetlb_lock
);
2186 #endif /* CONFIG_SYSCTL */
2188 void hugetlb_report_meminfo(struct seq_file
*m
)
2190 struct hstate
*h
= &default_hstate
;
2192 "HugePages_Total: %5lu\n"
2193 "HugePages_Free: %5lu\n"
2194 "HugePages_Rsvd: %5lu\n"
2195 "HugePages_Surp: %5lu\n"
2196 "Hugepagesize: %8lu kB\n",
2200 h
->surplus_huge_pages
,
2201 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2204 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2206 struct hstate
*h
= &default_hstate
;
2208 "Node %d HugePages_Total: %5u\n"
2209 "Node %d HugePages_Free: %5u\n"
2210 "Node %d HugePages_Surp: %5u\n",
2211 nid
, h
->nr_huge_pages_node
[nid
],
2212 nid
, h
->free_huge_pages_node
[nid
],
2213 nid
, h
->surplus_huge_pages_node
[nid
]);
2216 void hugetlb_show_meminfo(void)
2221 for_each_node_state(nid
, N_MEMORY
)
2223 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2225 h
->nr_huge_pages_node
[nid
],
2226 h
->free_huge_pages_node
[nid
],
2227 h
->surplus_huge_pages_node
[nid
],
2228 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2231 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2232 unsigned long hugetlb_total_pages(void)
2235 unsigned long nr_total_pages
= 0;
2238 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2239 return nr_total_pages
;
2242 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2246 spin_lock(&hugetlb_lock
);
2248 * When cpuset is configured, it breaks the strict hugetlb page
2249 * reservation as the accounting is done on a global variable. Such
2250 * reservation is completely rubbish in the presence of cpuset because
2251 * the reservation is not checked against page availability for the
2252 * current cpuset. Application can still potentially OOM'ed by kernel
2253 * with lack of free htlb page in cpuset that the task is in.
2254 * Attempt to enforce strict accounting with cpuset is almost
2255 * impossible (or too ugly) because cpuset is too fluid that
2256 * task or memory node can be dynamically moved between cpusets.
2258 * The change of semantics for shared hugetlb mapping with cpuset is
2259 * undesirable. However, in order to preserve some of the semantics,
2260 * we fall back to check against current free page availability as
2261 * a best attempt and hopefully to minimize the impact of changing
2262 * semantics that cpuset has.
2265 if (gather_surplus_pages(h
, delta
) < 0)
2268 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2269 return_unused_surplus_pages(h
, delta
);
2276 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2279 spin_unlock(&hugetlb_lock
);
2283 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2285 struct resv_map
*resv
= vma_resv_map(vma
);
2288 * This new VMA should share its siblings reservation map if present.
2289 * The VMA will only ever have a valid reservation map pointer where
2290 * it is being copied for another still existing VMA. As that VMA
2291 * has a reference to the reservation map it cannot disappear until
2292 * after this open call completes. It is therefore safe to take a
2293 * new reference here without additional locking.
2295 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2296 kref_get(&resv
->refs
);
2299 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2301 struct hstate
*h
= hstate_vma(vma
);
2302 struct resv_map
*resv
= vma_resv_map(vma
);
2303 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2304 unsigned long reserve
, start
, end
;
2306 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2309 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2310 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2312 reserve
= (end
- start
) - region_count(resv
, start
, end
);
2314 kref_put(&resv
->refs
, resv_map_release
);
2317 hugetlb_acct_memory(h
, -reserve
);
2318 hugepage_subpool_put_pages(spool
, reserve
);
2323 * We cannot handle pagefaults against hugetlb pages at all. They cause
2324 * handle_mm_fault() to try to instantiate regular-sized pages in the
2325 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2328 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2334 const struct vm_operations_struct hugetlb_vm_ops
= {
2335 .fault
= hugetlb_vm_op_fault
,
2336 .open
= hugetlb_vm_op_open
,
2337 .close
= hugetlb_vm_op_close
,
2340 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2346 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2347 vma
->vm_page_prot
)));
2349 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2350 vma
->vm_page_prot
));
2352 entry
= pte_mkyoung(entry
);
2353 entry
= pte_mkhuge(entry
);
2354 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2359 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2360 unsigned long address
, pte_t
*ptep
)
2364 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2365 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2366 update_mmu_cache(vma
, address
, ptep
);
2370 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2371 struct vm_area_struct
*vma
)
2373 pte_t
*src_pte
, *dst_pte
, entry
;
2374 struct page
*ptepage
;
2377 struct hstate
*h
= hstate_vma(vma
);
2378 unsigned long sz
= huge_page_size(h
);
2379 unsigned long mmun_start
; /* For mmu_notifiers */
2380 unsigned long mmun_end
; /* For mmu_notifiers */
2383 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2385 mmun_start
= vma
->vm_start
;
2386 mmun_end
= vma
->vm_end
;
2388 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
2390 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2391 spinlock_t
*src_ptl
, *dst_ptl
;
2392 src_pte
= huge_pte_offset(src
, addr
);
2395 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2401 /* If the pagetables are shared don't copy or take references */
2402 if (dst_pte
== src_pte
)
2405 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
2406 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
2407 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
2408 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2410 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2411 entry
= huge_ptep_get(src_pte
);
2412 ptepage
= pte_page(entry
);
2414 page_dup_rmap(ptepage
);
2415 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2417 spin_unlock(src_ptl
);
2418 spin_unlock(dst_ptl
);
2422 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
2427 static int is_hugetlb_entry_migration(pte_t pte
)
2431 if (huge_pte_none(pte
) || pte_present(pte
))
2433 swp
= pte_to_swp_entry(pte
);
2434 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2440 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2444 if (huge_pte_none(pte
) || pte_present(pte
))
2446 swp
= pte_to_swp_entry(pte
);
2447 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2453 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2454 unsigned long start
, unsigned long end
,
2455 struct page
*ref_page
)
2457 int force_flush
= 0;
2458 struct mm_struct
*mm
= vma
->vm_mm
;
2459 unsigned long address
;
2464 struct hstate
*h
= hstate_vma(vma
);
2465 unsigned long sz
= huge_page_size(h
);
2466 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2467 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2469 WARN_ON(!is_vm_hugetlb_page(vma
));
2470 BUG_ON(start
& ~huge_page_mask(h
));
2471 BUG_ON(end
& ~huge_page_mask(h
));
2473 tlb_start_vma(tlb
, vma
);
2474 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2476 for (address
= start
; address
< end
; address
+= sz
) {
2477 ptep
= huge_pte_offset(mm
, address
);
2481 ptl
= huge_pte_lock(h
, mm
, ptep
);
2482 if (huge_pmd_unshare(mm
, &address
, ptep
))
2485 pte
= huge_ptep_get(ptep
);
2486 if (huge_pte_none(pte
))
2490 * HWPoisoned hugepage is already unmapped and dropped reference
2492 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2493 huge_pte_clear(mm
, address
, ptep
);
2497 page
= pte_page(pte
);
2499 * If a reference page is supplied, it is because a specific
2500 * page is being unmapped, not a range. Ensure the page we
2501 * are about to unmap is the actual page of interest.
2504 if (page
!= ref_page
)
2508 * Mark the VMA as having unmapped its page so that
2509 * future faults in this VMA will fail rather than
2510 * looking like data was lost
2512 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2515 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2516 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2517 if (huge_pte_dirty(pte
))
2518 set_page_dirty(page
);
2520 page_remove_rmap(page
);
2521 force_flush
= !__tlb_remove_page(tlb
, page
);
2526 /* Bail out after unmapping reference page if supplied */
2535 * mmu_gather ran out of room to batch pages, we break out of
2536 * the PTE lock to avoid doing the potential expensive TLB invalidate
2537 * and page-free while holding it.
2542 if (address
< end
&& !ref_page
)
2545 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2546 tlb_end_vma(tlb
, vma
);
2549 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2550 struct vm_area_struct
*vma
, unsigned long start
,
2551 unsigned long end
, struct page
*ref_page
)
2553 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2556 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2557 * test will fail on a vma being torn down, and not grab a page table
2558 * on its way out. We're lucky that the flag has such an appropriate
2559 * name, and can in fact be safely cleared here. We could clear it
2560 * before the __unmap_hugepage_range above, but all that's necessary
2561 * is to clear it before releasing the i_mmap_mutex. This works
2562 * because in the context this is called, the VMA is about to be
2563 * destroyed and the i_mmap_mutex is held.
2565 vma
->vm_flags
&= ~VM_MAYSHARE
;
2568 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2569 unsigned long end
, struct page
*ref_page
)
2571 struct mm_struct
*mm
;
2572 struct mmu_gather tlb
;
2576 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2577 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2578 tlb_finish_mmu(&tlb
, start
, end
);
2582 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2583 * mappping it owns the reserve page for. The intention is to unmap the page
2584 * from other VMAs and let the children be SIGKILLed if they are faulting the
2587 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2588 struct page
*page
, unsigned long address
)
2590 struct hstate
*h
= hstate_vma(vma
);
2591 struct vm_area_struct
*iter_vma
;
2592 struct address_space
*mapping
;
2596 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2597 * from page cache lookup which is in HPAGE_SIZE units.
2599 address
= address
& huge_page_mask(h
);
2600 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2602 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2605 * Take the mapping lock for the duration of the table walk. As
2606 * this mapping should be shared between all the VMAs,
2607 * __unmap_hugepage_range() is called as the lock is already held
2609 mutex_lock(&mapping
->i_mmap_mutex
);
2610 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2611 /* Do not unmap the current VMA */
2612 if (iter_vma
== vma
)
2616 * Unmap the page from other VMAs without their own reserves.
2617 * They get marked to be SIGKILLed if they fault in these
2618 * areas. This is because a future no-page fault on this VMA
2619 * could insert a zeroed page instead of the data existing
2620 * from the time of fork. This would look like data corruption
2622 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2623 unmap_hugepage_range(iter_vma
, address
,
2624 address
+ huge_page_size(h
), page
);
2626 mutex_unlock(&mapping
->i_mmap_mutex
);
2632 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2633 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2634 * cannot race with other handlers or page migration.
2635 * Keep the pte_same checks anyway to make transition from the mutex easier.
2637 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2638 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2639 struct page
*pagecache_page
, spinlock_t
*ptl
)
2641 struct hstate
*h
= hstate_vma(vma
);
2642 struct page
*old_page
, *new_page
;
2643 int outside_reserve
= 0;
2644 unsigned long mmun_start
; /* For mmu_notifiers */
2645 unsigned long mmun_end
; /* For mmu_notifiers */
2647 old_page
= pte_page(pte
);
2650 /* If no-one else is actually using this page, avoid the copy
2651 * and just make the page writable */
2652 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2653 page_move_anon_rmap(old_page
, vma
, address
);
2654 set_huge_ptep_writable(vma
, address
, ptep
);
2659 * If the process that created a MAP_PRIVATE mapping is about to
2660 * perform a COW due to a shared page count, attempt to satisfy
2661 * the allocation without using the existing reserves. The pagecache
2662 * page is used to determine if the reserve at this address was
2663 * consumed or not. If reserves were used, a partial faulted mapping
2664 * at the time of fork() could consume its reserves on COW instead
2665 * of the full address range.
2667 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2668 old_page
!= pagecache_page
)
2669 outside_reserve
= 1;
2671 page_cache_get(old_page
);
2673 /* Drop page table lock as buddy allocator may be called */
2675 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2677 if (IS_ERR(new_page
)) {
2678 long err
= PTR_ERR(new_page
);
2679 page_cache_release(old_page
);
2682 * If a process owning a MAP_PRIVATE mapping fails to COW,
2683 * it is due to references held by a child and an insufficient
2684 * huge page pool. To guarantee the original mappers
2685 * reliability, unmap the page from child processes. The child
2686 * may get SIGKILLed if it later faults.
2688 if (outside_reserve
) {
2689 BUG_ON(huge_pte_none(pte
));
2690 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2691 BUG_ON(huge_pte_none(pte
));
2693 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2695 pte_same(huge_ptep_get(ptep
), pte
)))
2696 goto retry_avoidcopy
;
2698 * race occurs while re-acquiring page table
2699 * lock, and our job is done.
2706 /* Caller expects lock to be held */
2709 return VM_FAULT_OOM
;
2711 return VM_FAULT_SIGBUS
;
2715 * When the original hugepage is shared one, it does not have
2716 * anon_vma prepared.
2718 if (unlikely(anon_vma_prepare(vma
))) {
2719 page_cache_release(new_page
);
2720 page_cache_release(old_page
);
2721 /* Caller expects lock to be held */
2723 return VM_FAULT_OOM
;
2726 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2727 pages_per_huge_page(h
));
2728 __SetPageUptodate(new_page
);
2730 mmun_start
= address
& huge_page_mask(h
);
2731 mmun_end
= mmun_start
+ huge_page_size(h
);
2732 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2734 * Retake the page table lock to check for racing updates
2735 * before the page tables are altered
2738 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2739 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
2740 ClearPagePrivate(new_page
);
2743 huge_ptep_clear_flush(vma
, address
, ptep
);
2744 set_huge_pte_at(mm
, address
, ptep
,
2745 make_huge_pte(vma
, new_page
, 1));
2746 page_remove_rmap(old_page
);
2747 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2748 /* Make the old page be freed below */
2749 new_page
= old_page
;
2752 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2753 page_cache_release(new_page
);
2754 page_cache_release(old_page
);
2756 /* Caller expects lock to be held */
2761 /* Return the pagecache page at a given address within a VMA */
2762 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2763 struct vm_area_struct
*vma
, unsigned long address
)
2765 struct address_space
*mapping
;
2768 mapping
= vma
->vm_file
->f_mapping
;
2769 idx
= vma_hugecache_offset(h
, vma
, address
);
2771 return find_lock_page(mapping
, idx
);
2775 * Return whether there is a pagecache page to back given address within VMA.
2776 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2778 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2779 struct vm_area_struct
*vma
, unsigned long address
)
2781 struct address_space
*mapping
;
2785 mapping
= vma
->vm_file
->f_mapping
;
2786 idx
= vma_hugecache_offset(h
, vma
, address
);
2788 page
= find_get_page(mapping
, idx
);
2791 return page
!= NULL
;
2794 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2795 struct address_space
*mapping
, pgoff_t idx
,
2796 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2798 struct hstate
*h
= hstate_vma(vma
);
2799 int ret
= VM_FAULT_SIGBUS
;
2807 * Currently, we are forced to kill the process in the event the
2808 * original mapper has unmapped pages from the child due to a failed
2809 * COW. Warn that such a situation has occurred as it may not be obvious
2811 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2812 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2818 * Use page lock to guard against racing truncation
2819 * before we get page_table_lock.
2822 page
= find_lock_page(mapping
, idx
);
2824 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2827 page
= alloc_huge_page(vma
, address
, 0);
2829 ret
= PTR_ERR(page
);
2833 ret
= VM_FAULT_SIGBUS
;
2836 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2837 __SetPageUptodate(page
);
2839 if (vma
->vm_flags
& VM_MAYSHARE
) {
2841 struct inode
*inode
= mapping
->host
;
2843 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2850 ClearPagePrivate(page
);
2852 spin_lock(&inode
->i_lock
);
2853 inode
->i_blocks
+= blocks_per_huge_page(h
);
2854 spin_unlock(&inode
->i_lock
);
2857 if (unlikely(anon_vma_prepare(vma
))) {
2859 goto backout_unlocked
;
2865 * If memory error occurs between mmap() and fault, some process
2866 * don't have hwpoisoned swap entry for errored virtual address.
2867 * So we need to block hugepage fault by PG_hwpoison bit check.
2869 if (unlikely(PageHWPoison(page
))) {
2870 ret
= VM_FAULT_HWPOISON
|
2871 VM_FAULT_SET_HINDEX(hstate_index(h
));
2872 goto backout_unlocked
;
2877 * If we are going to COW a private mapping later, we examine the
2878 * pending reservations for this page now. This will ensure that
2879 * any allocations necessary to record that reservation occur outside
2882 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2883 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2885 goto backout_unlocked
;
2888 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
2890 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2895 if (!huge_pte_none(huge_ptep_get(ptep
)))
2899 ClearPagePrivate(page
);
2900 hugepage_add_new_anon_rmap(page
, vma
, address
);
2902 page_dup_rmap(page
);
2903 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2904 && (vma
->vm_flags
& VM_SHARED
)));
2905 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2907 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2908 /* Optimization, do the COW without a second fault */
2909 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
, ptl
);
2926 static u32
fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
2927 struct vm_area_struct
*vma
,
2928 struct address_space
*mapping
,
2929 pgoff_t idx
, unsigned long address
)
2931 unsigned long key
[2];
2934 if (vma
->vm_flags
& VM_SHARED
) {
2935 key
[0] = (unsigned long) mapping
;
2938 key
[0] = (unsigned long) mm
;
2939 key
[1] = address
>> huge_page_shift(h
);
2942 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
2944 return hash
& (num_fault_mutexes
- 1);
2948 * For uniprocesor systems we always use a single mutex, so just
2949 * return 0 and avoid the hashing overhead.
2951 static u32
fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
2952 struct vm_area_struct
*vma
,
2953 struct address_space
*mapping
,
2954 pgoff_t idx
, unsigned long address
)
2960 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2961 unsigned long address
, unsigned int flags
)
2968 struct page
*page
= NULL
;
2969 struct page
*pagecache_page
= NULL
;
2970 struct hstate
*h
= hstate_vma(vma
);
2971 struct address_space
*mapping
;
2973 address
&= huge_page_mask(h
);
2975 ptep
= huge_pte_offset(mm
, address
);
2977 entry
= huge_ptep_get(ptep
);
2978 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2979 migration_entry_wait_huge(vma
, mm
, ptep
);
2981 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2982 return VM_FAULT_HWPOISON_LARGE
|
2983 VM_FAULT_SET_HINDEX(hstate_index(h
));
2986 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2988 return VM_FAULT_OOM
;
2990 mapping
= vma
->vm_file
->f_mapping
;
2991 idx
= vma_hugecache_offset(h
, vma
, address
);
2994 * Serialize hugepage allocation and instantiation, so that we don't
2995 * get spurious allocation failures if two CPUs race to instantiate
2996 * the same page in the page cache.
2998 hash
= fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
2999 mutex_lock(&htlb_fault_mutex_table
[hash
]);
3001 entry
= huge_ptep_get(ptep
);
3002 if (huge_pte_none(entry
)) {
3003 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3010 * If we are going to COW the mapping later, we examine the pending
3011 * reservations for this page now. This will ensure that any
3012 * allocations necessary to record that reservation occur outside the
3013 * spinlock. For private mappings, we also lookup the pagecache
3014 * page now as it is used to determine if a reservation has been
3017 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3018 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3023 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3024 pagecache_page
= hugetlbfs_pagecache_page(h
,
3029 * hugetlb_cow() requires page locks of pte_page(entry) and
3030 * pagecache_page, so here we need take the former one
3031 * when page != pagecache_page or !pagecache_page.
3032 * Note that locking order is always pagecache_page -> page,
3033 * so no worry about deadlock.
3035 page
= pte_page(entry
);
3037 if (page
!= pagecache_page
)
3040 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
3042 /* Check for a racing update before calling hugetlb_cow */
3043 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3047 if (flags
& FAULT_FLAG_WRITE
) {
3048 if (!huge_pte_write(entry
)) {
3049 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
3050 pagecache_page
, ptl
);
3053 entry
= huge_pte_mkdirty(entry
);
3055 entry
= pte_mkyoung(entry
);
3056 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3057 flags
& FAULT_FLAG_WRITE
))
3058 update_mmu_cache(vma
, address
, ptep
);
3063 if (pagecache_page
) {
3064 unlock_page(pagecache_page
);
3065 put_page(pagecache_page
);
3067 if (page
!= pagecache_page
)
3072 mutex_unlock(&htlb_fault_mutex_table
[hash
]);
3076 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3077 struct page
**pages
, struct vm_area_struct
**vmas
,
3078 unsigned long *position
, unsigned long *nr_pages
,
3079 long i
, unsigned int flags
)
3081 unsigned long pfn_offset
;
3082 unsigned long vaddr
= *position
;
3083 unsigned long remainder
= *nr_pages
;
3084 struct hstate
*h
= hstate_vma(vma
);
3086 while (vaddr
< vma
->vm_end
&& remainder
) {
3088 spinlock_t
*ptl
= NULL
;
3093 * Some archs (sparc64, sh*) have multiple pte_ts to
3094 * each hugepage. We have to make sure we get the
3095 * first, for the page indexing below to work.
3097 * Note that page table lock is not held when pte is null.
3099 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
3101 ptl
= huge_pte_lock(h
, mm
, pte
);
3102 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
3105 * When coredumping, it suits get_dump_page if we just return
3106 * an error where there's an empty slot with no huge pagecache
3107 * to back it. This way, we avoid allocating a hugepage, and
3108 * the sparse dumpfile avoids allocating disk blocks, but its
3109 * huge holes still show up with zeroes where they need to be.
3111 if (absent
&& (flags
& FOLL_DUMP
) &&
3112 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
3120 * We need call hugetlb_fault for both hugepages under migration
3121 * (in which case hugetlb_fault waits for the migration,) and
3122 * hwpoisoned hugepages (in which case we need to prevent the
3123 * caller from accessing to them.) In order to do this, we use
3124 * here is_swap_pte instead of is_hugetlb_entry_migration and
3125 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3126 * both cases, and because we can't follow correct pages
3127 * directly from any kind of swap entries.
3129 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
3130 ((flags
& FOLL_WRITE
) &&
3131 !huge_pte_write(huge_ptep_get(pte
)))) {
3136 ret
= hugetlb_fault(mm
, vma
, vaddr
,
3137 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
3138 if (!(ret
& VM_FAULT_ERROR
))
3145 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
3146 page
= pte_page(huge_ptep_get(pte
));
3149 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3150 get_page_foll(pages
[i
]);
3160 if (vaddr
< vma
->vm_end
&& remainder
&&
3161 pfn_offset
< pages_per_huge_page(h
)) {
3163 * We use pfn_offset to avoid touching the pageframes
3164 * of this compound page.
3170 *nr_pages
= remainder
;
3173 return i
? i
: -EFAULT
;
3176 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3177 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3179 struct mm_struct
*mm
= vma
->vm_mm
;
3180 unsigned long start
= address
;
3183 struct hstate
*h
= hstate_vma(vma
);
3184 unsigned long pages
= 0;
3186 BUG_ON(address
>= end
);
3187 flush_cache_range(vma
, address
, end
);
3189 mmu_notifier_invalidate_range_start(mm
, start
, end
);
3190 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3191 for (; address
< end
; address
+= huge_page_size(h
)) {
3193 ptep
= huge_pte_offset(mm
, address
);
3196 ptl
= huge_pte_lock(h
, mm
, ptep
);
3197 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3202 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3203 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3204 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3205 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3206 set_huge_pte_at(mm
, address
, ptep
, pte
);
3212 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3213 * may have cleared our pud entry and done put_page on the page table:
3214 * once we release i_mmap_mutex, another task can do the final put_page
3215 * and that page table be reused and filled with junk.
3217 flush_tlb_range(vma
, start
, end
);
3218 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3219 mmu_notifier_invalidate_range_end(mm
, start
, end
);
3221 return pages
<< h
->order
;
3224 int hugetlb_reserve_pages(struct inode
*inode
,
3226 struct vm_area_struct
*vma
,
3227 vm_flags_t vm_flags
)
3230 struct hstate
*h
= hstate_inode(inode
);
3231 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3232 struct resv_map
*resv_map
;
3235 * Only apply hugepage reservation if asked. At fault time, an
3236 * attempt will be made for VM_NORESERVE to allocate a page
3237 * without using reserves
3239 if (vm_flags
& VM_NORESERVE
)
3243 * Shared mappings base their reservation on the number of pages that
3244 * are already allocated on behalf of the file. Private mappings need
3245 * to reserve the full area even if read-only as mprotect() may be
3246 * called to make the mapping read-write. Assume !vma is a shm mapping
3248 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
3249 resv_map
= inode_resv_map(inode
);
3251 chg
= region_chg(resv_map
, from
, to
);
3254 resv_map
= resv_map_alloc();
3260 set_vma_resv_map(vma
, resv_map
);
3261 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3269 /* There must be enough pages in the subpool for the mapping */
3270 if (hugepage_subpool_get_pages(spool
, chg
)) {
3276 * Check enough hugepages are available for the reservation.
3277 * Hand the pages back to the subpool if there are not
3279 ret
= hugetlb_acct_memory(h
, chg
);
3281 hugepage_subpool_put_pages(spool
, chg
);
3286 * Account for the reservations made. Shared mappings record regions
3287 * that have reservations as they are shared by multiple VMAs.
3288 * When the last VMA disappears, the region map says how much
3289 * the reservation was and the page cache tells how much of
3290 * the reservation was consumed. Private mappings are per-VMA and
3291 * only the consumed reservations are tracked. When the VMA
3292 * disappears, the original reservation is the VMA size and the
3293 * consumed reservations are stored in the map. Hence, nothing
3294 * else has to be done for private mappings here
3296 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3297 region_add(resv_map
, from
, to
);
3300 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3301 kref_put(&resv_map
->refs
, resv_map_release
);
3305 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3307 struct hstate
*h
= hstate_inode(inode
);
3308 struct resv_map
*resv_map
= inode_resv_map(inode
);
3310 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3313 chg
= region_truncate(resv_map
, offset
);
3314 spin_lock(&inode
->i_lock
);
3315 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3316 spin_unlock(&inode
->i_lock
);
3318 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3319 hugetlb_acct_memory(h
, -(chg
- freed
));
3322 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3323 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3324 struct vm_area_struct
*vma
,
3325 unsigned long addr
, pgoff_t idx
)
3327 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3329 unsigned long sbase
= saddr
& PUD_MASK
;
3330 unsigned long s_end
= sbase
+ PUD_SIZE
;
3332 /* Allow segments to share if only one is marked locked */
3333 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3334 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3337 * match the virtual addresses, permission and the alignment of the
3340 if (pmd_index(addr
) != pmd_index(saddr
) ||
3341 vm_flags
!= svm_flags
||
3342 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3348 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3350 unsigned long base
= addr
& PUD_MASK
;
3351 unsigned long end
= base
+ PUD_SIZE
;
3354 * check on proper vm_flags and page table alignment
3356 if (vma
->vm_flags
& VM_MAYSHARE
&&
3357 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3363 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3364 * and returns the corresponding pte. While this is not necessary for the
3365 * !shared pmd case because we can allocate the pmd later as well, it makes the
3366 * code much cleaner. pmd allocation is essential for the shared case because
3367 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3368 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3369 * bad pmd for sharing.
3371 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3373 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3374 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3375 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3377 struct vm_area_struct
*svma
;
3378 unsigned long saddr
;
3383 if (!vma_shareable(vma
, addr
))
3384 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3386 mutex_lock(&mapping
->i_mmap_mutex
);
3387 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3391 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3393 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3395 get_page(virt_to_page(spte
));
3404 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, spte
);
3407 pud_populate(mm
, pud
,
3408 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3410 put_page(virt_to_page(spte
));
3413 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3414 mutex_unlock(&mapping
->i_mmap_mutex
);
3419 * unmap huge page backed by shared pte.
3421 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3422 * indicated by page_count > 1, unmap is achieved by clearing pud and
3423 * decrementing the ref count. If count == 1, the pte page is not shared.
3425 * called with page table lock held.
3427 * returns: 1 successfully unmapped a shared pte page
3428 * 0 the underlying pte page is not shared, or it is the last user
3430 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3432 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3433 pud_t
*pud
= pud_offset(pgd
, *addr
);
3435 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3436 if (page_count(virt_to_page(ptep
)) == 1)
3440 put_page(virt_to_page(ptep
));
3441 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3444 #define want_pmd_share() (1)
3445 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3446 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3450 #define want_pmd_share() (0)
3451 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3453 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3454 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3455 unsigned long addr
, unsigned long sz
)
3461 pgd
= pgd_offset(mm
, addr
);
3462 pud
= pud_alloc(mm
, pgd
, addr
);
3464 if (sz
== PUD_SIZE
) {
3467 BUG_ON(sz
!= PMD_SIZE
);
3468 if (want_pmd_share() && pud_none(*pud
))
3469 pte
= huge_pmd_share(mm
, addr
, pud
);
3471 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3474 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3479 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3485 pgd
= pgd_offset(mm
, addr
);
3486 if (pgd_present(*pgd
)) {
3487 pud
= pud_offset(pgd
, addr
);
3488 if (pud_present(*pud
)) {
3490 return (pte_t
*)pud
;
3491 pmd
= pmd_offset(pud
, addr
);
3494 return (pte_t
*) pmd
;
3498 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3499 pmd_t
*pmd
, int write
)
3503 page
= pte_page(*(pte_t
*)pmd
);
3505 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3510 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3511 pud_t
*pud
, int write
)
3515 page
= pte_page(*(pte_t
*)pud
);
3517 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3521 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3523 /* Can be overriden by architectures */
3524 struct page
* __weak
3525 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3526 pud_t
*pud
, int write
)
3532 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3534 #ifdef CONFIG_MEMORY_FAILURE
3536 /* Should be called in hugetlb_lock */
3537 static int is_hugepage_on_freelist(struct page
*hpage
)
3541 struct hstate
*h
= page_hstate(hpage
);
3542 int nid
= page_to_nid(hpage
);
3544 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3551 * This function is called from memory failure code.
3552 * Assume the caller holds page lock of the head page.
3554 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3556 struct hstate
*h
= page_hstate(hpage
);
3557 int nid
= page_to_nid(hpage
);
3560 spin_lock(&hugetlb_lock
);
3561 if (is_hugepage_on_freelist(hpage
)) {
3563 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3564 * but dangling hpage->lru can trigger list-debug warnings
3565 * (this happens when we call unpoison_memory() on it),
3566 * so let it point to itself with list_del_init().
3568 list_del_init(&hpage
->lru
);
3569 set_page_refcounted(hpage
);
3570 h
->free_huge_pages
--;
3571 h
->free_huge_pages_node
[nid
]--;
3574 spin_unlock(&hugetlb_lock
);
3579 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
3581 VM_BUG_ON_PAGE(!PageHead(page
), page
);
3582 if (!get_page_unless_zero(page
))
3584 spin_lock(&hugetlb_lock
);
3585 list_move_tail(&page
->lru
, list
);
3586 spin_unlock(&hugetlb_lock
);
3590 void putback_active_hugepage(struct page
*page
)
3592 VM_BUG_ON_PAGE(!PageHead(page
), page
);
3593 spin_lock(&hugetlb_lock
);
3594 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
3595 spin_unlock(&hugetlb_lock
);
3599 bool is_hugepage_active(struct page
*page
)
3601 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
3603 * This function can be called for a tail page because the caller,
3604 * scan_movable_pages, scans through a given pfn-range which typically
3605 * covers one memory block. In systems using gigantic hugepage (1GB
3606 * for x86_64,) a hugepage is larger than a memory block, and we don't
3607 * support migrating such large hugepages for now, so return false
3608 * when called for tail pages.
3613 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3614 * so we should return false for them.
3616 if (unlikely(PageHWPoison(page
)))
3618 return page_count(page
) > 0;