2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
26 #include <asm/pgtable.h>
30 #include <linux/hugetlb.h>
31 #include <linux/hugetlb_cgroup.h>
32 #include <linux/node.h>
35 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
36 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
37 unsigned long hugepages_treat_as_movable
;
39 int hugetlb_max_hstate __read_mostly
;
40 unsigned int default_hstate_idx
;
41 struct hstate hstates
[HUGE_MAX_HSTATE
];
43 __initdata
LIST_HEAD(huge_boot_pages
);
45 /* for command line parsing */
46 static struct hstate
* __initdata parsed_hstate
;
47 static unsigned long __initdata default_hstate_max_huge_pages
;
48 static unsigned long __initdata default_hstate_size
;
51 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
53 DEFINE_SPINLOCK(hugetlb_lock
);
55 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
57 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
59 spin_unlock(&spool
->lock
);
61 /* If no pages are used, and no other handles to the subpool
62 * remain, free the subpool the subpool remain */
67 struct hugepage_subpool
*hugepage_new_subpool(long nr_blocks
)
69 struct hugepage_subpool
*spool
;
71 spool
= kmalloc(sizeof(*spool
), GFP_KERNEL
);
75 spin_lock_init(&spool
->lock
);
77 spool
->max_hpages
= nr_blocks
;
78 spool
->used_hpages
= 0;
83 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
85 spin_lock(&spool
->lock
);
86 BUG_ON(!spool
->count
);
88 unlock_or_release_subpool(spool
);
91 static int hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
99 spin_lock(&spool
->lock
);
100 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
) {
101 spool
->used_hpages
+= delta
;
105 spin_unlock(&spool
->lock
);
110 static void hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
116 spin_lock(&spool
->lock
);
117 spool
->used_hpages
-= delta
;
118 /* If hugetlbfs_put_super couldn't free spool due to
119 * an outstanding quota reference, free it now. */
120 unlock_or_release_subpool(spool
);
123 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
125 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
128 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
130 return subpool_inode(file_inode(vma
->vm_file
));
134 * Region tracking -- allows tracking of reservations and instantiated pages
135 * across the pages in a mapping.
137 * The region data structures are protected by a combination of the mmap_sem
138 * and the hugetlb_instantiation_mutex. To access or modify a region the caller
139 * must either hold the mmap_sem for write, or the mmap_sem for read and
140 * the hugetlb_instantiation_mutex:
142 * down_write(&mm->mmap_sem);
144 * down_read(&mm->mmap_sem);
145 * mutex_lock(&hugetlb_instantiation_mutex);
148 struct list_head link
;
153 static long region_add(struct list_head
*head
, long f
, long t
)
155 struct file_region
*rg
, *nrg
, *trg
;
157 /* Locate the region we are either in or before. */
158 list_for_each_entry(rg
, head
, link
)
162 /* Round our left edge to the current segment if it encloses us. */
166 /* Check for and consume any regions we now overlap with. */
168 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
169 if (&rg
->link
== head
)
174 /* If this area reaches higher then extend our area to
175 * include it completely. If this is not the first area
176 * which we intend to reuse, free it. */
189 static long region_chg(struct list_head
*head
, long f
, long t
)
191 struct file_region
*rg
, *nrg
;
194 /* Locate the region we are before or in. */
195 list_for_each_entry(rg
, head
, link
)
199 /* If we are below the current region then a new region is required.
200 * Subtle, allocate a new region at the position but make it zero
201 * size such that we can guarantee to record the reservation. */
202 if (&rg
->link
== head
|| t
< rg
->from
) {
203 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
208 INIT_LIST_HEAD(&nrg
->link
);
209 list_add(&nrg
->link
, rg
->link
.prev
);
214 /* Round our left edge to the current segment if it encloses us. */
219 /* Check for and consume any regions we now overlap with. */
220 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
221 if (&rg
->link
== head
)
226 /* We overlap with this area, if it extends further than
227 * us then we must extend ourselves. Account for its
228 * existing reservation. */
233 chg
-= rg
->to
- rg
->from
;
238 static long region_truncate(struct list_head
*head
, long end
)
240 struct file_region
*rg
, *trg
;
243 /* Locate the region we are either in or before. */
244 list_for_each_entry(rg
, head
, link
)
247 if (&rg
->link
== head
)
250 /* If we are in the middle of a region then adjust it. */
251 if (end
> rg
->from
) {
254 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
257 /* Drop any remaining regions. */
258 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
259 if (&rg
->link
== head
)
261 chg
+= rg
->to
- rg
->from
;
268 static long region_count(struct list_head
*head
, long f
, long t
)
270 struct file_region
*rg
;
273 /* Locate each segment we overlap with, and count that overlap. */
274 list_for_each_entry(rg
, head
, link
) {
283 seg_from
= max(rg
->from
, f
);
284 seg_to
= min(rg
->to
, t
);
286 chg
+= seg_to
- seg_from
;
293 * Convert the address within this vma to the page offset within
294 * the mapping, in pagecache page units; huge pages here.
296 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
297 struct vm_area_struct
*vma
, unsigned long address
)
299 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
300 (vma
->vm_pgoff
>> huge_page_order(h
));
303 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
304 unsigned long address
)
306 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
310 * Return the size of the pages allocated when backing a VMA. In the majority
311 * cases this will be same size as used by the page table entries.
313 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
315 struct hstate
*hstate
;
317 if (!is_vm_hugetlb_page(vma
))
320 hstate
= hstate_vma(vma
);
322 return 1UL << huge_page_shift(hstate
);
324 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
327 * Return the page size being used by the MMU to back a VMA. In the majority
328 * of cases, the page size used by the kernel matches the MMU size. On
329 * architectures where it differs, an architecture-specific version of this
330 * function is required.
332 #ifndef vma_mmu_pagesize
333 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
335 return vma_kernel_pagesize(vma
);
340 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
341 * bits of the reservation map pointer, which are always clear due to
344 #define HPAGE_RESV_OWNER (1UL << 0)
345 #define HPAGE_RESV_UNMAPPED (1UL << 1)
346 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
349 * These helpers are used to track how many pages are reserved for
350 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
351 * is guaranteed to have their future faults succeed.
353 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
354 * the reserve counters are updated with the hugetlb_lock held. It is safe
355 * to reset the VMA at fork() time as it is not in use yet and there is no
356 * chance of the global counters getting corrupted as a result of the values.
358 * The private mapping reservation is represented in a subtly different
359 * manner to a shared mapping. A shared mapping has a region map associated
360 * with the underlying file, this region map represents the backing file
361 * pages which have ever had a reservation assigned which this persists even
362 * after the page is instantiated. A private mapping has a region map
363 * associated with the original mmap which is attached to all VMAs which
364 * reference it, this region map represents those offsets which have consumed
365 * reservation ie. where pages have been instantiated.
367 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
369 return (unsigned long)vma
->vm_private_data
;
372 static void set_vma_private_data(struct vm_area_struct
*vma
,
375 vma
->vm_private_data
= (void *)value
;
380 struct list_head regions
;
383 static struct resv_map
*resv_map_alloc(void)
385 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
389 kref_init(&resv_map
->refs
);
390 INIT_LIST_HEAD(&resv_map
->regions
);
395 static void resv_map_release(struct kref
*ref
)
397 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
399 /* Clear out any active regions before we release the map. */
400 region_truncate(&resv_map
->regions
, 0);
404 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
406 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
407 if (!(vma
->vm_flags
& VM_MAYSHARE
))
408 return (struct resv_map
*)(get_vma_private_data(vma
) &
413 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
415 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
416 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
418 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
419 HPAGE_RESV_MASK
) | (unsigned long)map
);
422 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
424 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
425 VM_BUG_ON(vma
->vm_flags
& VM_MAYSHARE
);
427 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
430 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
432 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
434 return (get_vma_private_data(vma
) & flag
) != 0;
437 /* Decrement the reserved pages in the hugepage pool by one */
438 static void decrement_hugepage_resv_vma(struct hstate
*h
,
439 struct vm_area_struct
*vma
)
441 if (vma
->vm_flags
& VM_NORESERVE
)
444 if (vma
->vm_flags
& VM_MAYSHARE
) {
445 /* Shared mappings always use reserves */
446 h
->resv_huge_pages
--;
447 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
449 * Only the process that called mmap() has reserves for
452 h
->resv_huge_pages
--;
456 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
457 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
459 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
460 if (!(vma
->vm_flags
& VM_MAYSHARE
))
461 vma
->vm_private_data
= (void *)0;
464 /* Returns true if the VMA has associated reserve pages */
465 static int vma_has_reserves(struct vm_area_struct
*vma
)
467 if (vma
->vm_flags
& VM_MAYSHARE
)
469 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
474 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
477 struct hstate
*h
= page_hstate(src
);
478 struct page
*dst_base
= dst
;
479 struct page
*src_base
= src
;
481 for (i
= 0; i
< pages_per_huge_page(h
); ) {
483 copy_highpage(dst
, src
);
486 dst
= mem_map_next(dst
, dst_base
, i
);
487 src
= mem_map_next(src
, src_base
, i
);
491 void copy_huge_page(struct page
*dst
, struct page
*src
)
494 struct hstate
*h
= page_hstate(src
);
496 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
497 copy_gigantic_page(dst
, src
);
502 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
504 copy_highpage(dst
+ i
, src
+ i
);
508 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
510 int nid
= page_to_nid(page
);
511 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
512 h
->free_huge_pages
++;
513 h
->free_huge_pages_node
[nid
]++;
516 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
520 if (list_empty(&h
->hugepage_freelists
[nid
]))
522 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
523 list_move(&page
->lru
, &h
->hugepage_activelist
);
524 set_page_refcounted(page
);
525 h
->free_huge_pages
--;
526 h
->free_huge_pages_node
[nid
]--;
530 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
531 struct vm_area_struct
*vma
,
532 unsigned long address
, int avoid_reserve
)
534 struct page
*page
= NULL
;
535 struct mempolicy
*mpol
;
536 nodemask_t
*nodemask
;
537 struct zonelist
*zonelist
;
540 unsigned int cpuset_mems_cookie
;
543 * A child process with MAP_PRIVATE mappings created by their parent
544 * have no page reserves. This check ensures that reservations are
545 * not "stolen". The child may still get SIGKILLed
547 if (!vma_has_reserves(vma
) &&
548 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
551 /* If reserves cannot be used, ensure enough pages are in the pool */
552 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
556 cpuset_mems_cookie
= get_mems_allowed();
557 zonelist
= huge_zonelist(vma
, address
,
558 htlb_alloc_mask
, &mpol
, &nodemask
);
560 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
561 MAX_NR_ZONES
- 1, nodemask
) {
562 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
563 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
566 decrement_hugepage_resv_vma(h
, vma
);
573 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
581 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
585 VM_BUG_ON(h
->order
>= MAX_ORDER
);
588 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
589 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
590 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
591 1 << PG_referenced
| 1 << PG_dirty
|
592 1 << PG_active
| 1 << PG_reserved
|
593 1 << PG_private
| 1 << PG_writeback
);
595 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
596 set_compound_page_dtor(page
, NULL
);
597 set_page_refcounted(page
);
598 arch_release_hugepage(page
);
599 __free_pages(page
, huge_page_order(h
));
602 struct hstate
*size_to_hstate(unsigned long size
)
607 if (huge_page_size(h
) == size
)
613 static void free_huge_page(struct page
*page
)
616 * Can't pass hstate in here because it is called from the
617 * compound page destructor.
619 struct hstate
*h
= page_hstate(page
);
620 int nid
= page_to_nid(page
);
621 struct hugepage_subpool
*spool
=
622 (struct hugepage_subpool
*)page_private(page
);
624 set_page_private(page
, 0);
625 page
->mapping
= NULL
;
626 BUG_ON(page_count(page
));
627 BUG_ON(page_mapcount(page
));
629 spin_lock(&hugetlb_lock
);
630 hugetlb_cgroup_uncharge_page(hstate_index(h
),
631 pages_per_huge_page(h
), page
);
632 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
633 /* remove the page from active list */
634 list_del(&page
->lru
);
635 update_and_free_page(h
, page
);
636 h
->surplus_huge_pages
--;
637 h
->surplus_huge_pages_node
[nid
]--;
639 arch_clear_hugepage_flags(page
);
640 enqueue_huge_page(h
, page
);
642 spin_unlock(&hugetlb_lock
);
643 hugepage_subpool_put_pages(spool
, 1);
646 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
648 INIT_LIST_HEAD(&page
->lru
);
649 set_compound_page_dtor(page
, free_huge_page
);
650 spin_lock(&hugetlb_lock
);
651 set_hugetlb_cgroup(page
, NULL
);
653 h
->nr_huge_pages_node
[nid
]++;
654 spin_unlock(&hugetlb_lock
);
655 put_page(page
); /* free it into the hugepage allocator */
658 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
661 int nr_pages
= 1 << order
;
662 struct page
*p
= page
+ 1;
664 /* we rely on prep_new_huge_page to set the destructor */
665 set_compound_order(page
, order
);
667 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
669 set_page_count(p
, 0);
670 p
->first_page
= page
;
675 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
676 * transparent huge pages. See the PageTransHuge() documentation for more
679 int PageHuge(struct page
*page
)
681 compound_page_dtor
*dtor
;
683 if (!PageCompound(page
))
686 page
= compound_head(page
);
687 dtor
= get_compound_page_dtor(page
);
689 return dtor
== free_huge_page
;
691 EXPORT_SYMBOL_GPL(PageHuge
);
693 pgoff_t
__basepage_index(struct page
*page
)
695 struct page
*page_head
= compound_head(page
);
696 pgoff_t index
= page_index(page_head
);
697 unsigned long compound_idx
;
699 if (!PageHuge(page_head
))
700 return page_index(page
);
702 if (compound_order(page_head
) >= MAX_ORDER
)
703 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
705 compound_idx
= page
- page_head
;
707 return (index
<< compound_order(page_head
)) + compound_idx
;
710 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
714 if (h
->order
>= MAX_ORDER
)
717 page
= alloc_pages_exact_node(nid
,
718 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
719 __GFP_REPEAT
|__GFP_NOWARN
,
722 if (arch_prepare_hugepage(page
)) {
723 __free_pages(page
, huge_page_order(h
));
726 prep_new_huge_page(h
, page
, nid
);
733 * common helper functions for hstate_next_node_to_{alloc|free}.
734 * We may have allocated or freed a huge page based on a different
735 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
736 * be outside of *nodes_allowed. Ensure that we use an allowed
737 * node for alloc or free.
739 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
741 nid
= next_node(nid
, *nodes_allowed
);
742 if (nid
== MAX_NUMNODES
)
743 nid
= first_node(*nodes_allowed
);
744 VM_BUG_ON(nid
>= MAX_NUMNODES
);
749 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
751 if (!node_isset(nid
, *nodes_allowed
))
752 nid
= next_node_allowed(nid
, nodes_allowed
);
757 * returns the previously saved node ["this node"] from which to
758 * allocate a persistent huge page for the pool and advance the
759 * next node from which to allocate, handling wrap at end of node
762 static int hstate_next_node_to_alloc(struct hstate
*h
,
763 nodemask_t
*nodes_allowed
)
767 VM_BUG_ON(!nodes_allowed
);
769 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
770 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
776 * helper for free_pool_huge_page() - return the previously saved
777 * node ["this node"] from which to free a huge page. Advance the
778 * next node id whether or not we find a free huge page to free so
779 * that the next attempt to free addresses the next node.
781 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
785 VM_BUG_ON(!nodes_allowed
);
787 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
788 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
793 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
794 for (nr_nodes = nodes_weight(*mask); \
796 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
799 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
800 for (nr_nodes = nodes_weight(*mask); \
802 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
805 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
811 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
812 page
= alloc_fresh_huge_page_node(h
, node
);
820 count_vm_event(HTLB_BUDDY_PGALLOC
);
822 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
828 * Free huge page from pool from next node to free.
829 * Attempt to keep persistent huge pages more or less
830 * balanced over allowed nodes.
831 * Called with hugetlb_lock locked.
833 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
839 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
841 * If we're returning unused surplus pages, only examine
842 * nodes with surplus pages.
844 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
845 !list_empty(&h
->hugepage_freelists
[node
])) {
847 list_entry(h
->hugepage_freelists
[node
].next
,
849 list_del(&page
->lru
);
850 h
->free_huge_pages
--;
851 h
->free_huge_pages_node
[node
]--;
853 h
->surplus_huge_pages
--;
854 h
->surplus_huge_pages_node
[node
]--;
856 update_and_free_page(h
, page
);
865 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
870 if (h
->order
>= MAX_ORDER
)
874 * Assume we will successfully allocate the surplus page to
875 * prevent racing processes from causing the surplus to exceed
878 * This however introduces a different race, where a process B
879 * tries to grow the static hugepage pool while alloc_pages() is
880 * called by process A. B will only examine the per-node
881 * counters in determining if surplus huge pages can be
882 * converted to normal huge pages in adjust_pool_surplus(). A
883 * won't be able to increment the per-node counter, until the
884 * lock is dropped by B, but B doesn't drop hugetlb_lock until
885 * no more huge pages can be converted from surplus to normal
886 * state (and doesn't try to convert again). Thus, we have a
887 * case where a surplus huge page exists, the pool is grown, and
888 * the surplus huge page still exists after, even though it
889 * should just have been converted to a normal huge page. This
890 * does not leak memory, though, as the hugepage will be freed
891 * once it is out of use. It also does not allow the counters to
892 * go out of whack in adjust_pool_surplus() as we don't modify
893 * the node values until we've gotten the hugepage and only the
894 * per-node value is checked there.
896 spin_lock(&hugetlb_lock
);
897 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
898 spin_unlock(&hugetlb_lock
);
902 h
->surplus_huge_pages
++;
904 spin_unlock(&hugetlb_lock
);
906 if (nid
== NUMA_NO_NODE
)
907 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
908 __GFP_REPEAT
|__GFP_NOWARN
,
911 page
= alloc_pages_exact_node(nid
,
912 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
913 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
915 if (page
&& arch_prepare_hugepage(page
)) {
916 __free_pages(page
, huge_page_order(h
));
920 spin_lock(&hugetlb_lock
);
922 INIT_LIST_HEAD(&page
->lru
);
923 r_nid
= page_to_nid(page
);
924 set_compound_page_dtor(page
, free_huge_page
);
925 set_hugetlb_cgroup(page
, NULL
);
927 * We incremented the global counters already
929 h
->nr_huge_pages_node
[r_nid
]++;
930 h
->surplus_huge_pages_node
[r_nid
]++;
931 __count_vm_event(HTLB_BUDDY_PGALLOC
);
934 h
->surplus_huge_pages
--;
935 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
937 spin_unlock(&hugetlb_lock
);
943 * This allocation function is useful in the context where vma is irrelevant.
944 * E.g. soft-offlining uses this function because it only cares physical
945 * address of error page.
947 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
951 spin_lock(&hugetlb_lock
);
952 page
= dequeue_huge_page_node(h
, nid
);
953 spin_unlock(&hugetlb_lock
);
956 page
= alloc_buddy_huge_page(h
, nid
);
962 * Increase the hugetlb pool such that it can accommodate a reservation
965 static int gather_surplus_pages(struct hstate
*h
, int delta
)
967 struct list_head surplus_list
;
968 struct page
*page
, *tmp
;
970 int needed
, allocated
;
971 bool alloc_ok
= true;
973 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
975 h
->resv_huge_pages
+= delta
;
980 INIT_LIST_HEAD(&surplus_list
);
984 spin_unlock(&hugetlb_lock
);
985 for (i
= 0; i
< needed
; i
++) {
986 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
991 list_add(&page
->lru
, &surplus_list
);
996 * After retaking hugetlb_lock, we need to recalculate 'needed'
997 * because either resv_huge_pages or free_huge_pages may have changed.
999 spin_lock(&hugetlb_lock
);
1000 needed
= (h
->resv_huge_pages
+ delta
) -
1001 (h
->free_huge_pages
+ allocated
);
1006 * We were not able to allocate enough pages to
1007 * satisfy the entire reservation so we free what
1008 * we've allocated so far.
1013 * The surplus_list now contains _at_least_ the number of extra pages
1014 * needed to accommodate the reservation. Add the appropriate number
1015 * of pages to the hugetlb pool and free the extras back to the buddy
1016 * allocator. Commit the entire reservation here to prevent another
1017 * process from stealing the pages as they are added to the pool but
1018 * before they are reserved.
1020 needed
+= allocated
;
1021 h
->resv_huge_pages
+= delta
;
1024 /* Free the needed pages to the hugetlb pool */
1025 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1029 * This page is now managed by the hugetlb allocator and has
1030 * no users -- drop the buddy allocator's reference.
1032 put_page_testzero(page
);
1033 VM_BUG_ON(page_count(page
));
1034 enqueue_huge_page(h
, page
);
1037 spin_unlock(&hugetlb_lock
);
1039 /* Free unnecessary surplus pages to the buddy allocator */
1040 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1042 spin_lock(&hugetlb_lock
);
1048 * When releasing a hugetlb pool reservation, any surplus pages that were
1049 * allocated to satisfy the reservation must be explicitly freed if they were
1051 * Called with hugetlb_lock held.
1053 static void return_unused_surplus_pages(struct hstate
*h
,
1054 unsigned long unused_resv_pages
)
1056 unsigned long nr_pages
;
1058 /* Uncommit the reservation */
1059 h
->resv_huge_pages
-= unused_resv_pages
;
1061 /* Cannot return gigantic pages currently */
1062 if (h
->order
>= MAX_ORDER
)
1065 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1068 * We want to release as many surplus pages as possible, spread
1069 * evenly across all nodes with memory. Iterate across these nodes
1070 * until we can no longer free unreserved surplus pages. This occurs
1071 * when the nodes with surplus pages have no free pages.
1072 * free_pool_huge_page() will balance the the freed pages across the
1073 * on-line nodes with memory and will handle the hstate accounting.
1075 while (nr_pages
--) {
1076 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1082 * Determine if the huge page at addr within the vma has an associated
1083 * reservation. Where it does not we will need to logically increase
1084 * reservation and actually increase subpool usage before an allocation
1085 * can occur. Where any new reservation would be required the
1086 * reservation change is prepared, but not committed. Once the page
1087 * has been allocated from the subpool and instantiated the change should
1088 * be committed via vma_commit_reservation. No action is required on
1091 static long vma_needs_reservation(struct hstate
*h
,
1092 struct vm_area_struct
*vma
, unsigned long addr
)
1094 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1095 struct inode
*inode
= mapping
->host
;
1097 if (vma
->vm_flags
& VM_MAYSHARE
) {
1098 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1099 return region_chg(&inode
->i_mapping
->private_list
,
1102 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1107 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1108 struct resv_map
*reservations
= vma_resv_map(vma
);
1110 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1116 static void vma_commit_reservation(struct hstate
*h
,
1117 struct vm_area_struct
*vma
, unsigned long addr
)
1119 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1120 struct inode
*inode
= mapping
->host
;
1122 if (vma
->vm_flags
& VM_MAYSHARE
) {
1123 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1124 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1126 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1127 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1128 struct resv_map
*reservations
= vma_resv_map(vma
);
1130 /* Mark this page used in the map. */
1131 region_add(&reservations
->regions
, idx
, idx
+ 1);
1135 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1136 unsigned long addr
, int avoid_reserve
)
1138 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1139 struct hstate
*h
= hstate_vma(vma
);
1143 struct hugetlb_cgroup
*h_cg
;
1145 idx
= hstate_index(h
);
1147 * Processes that did not create the mapping will have no
1148 * reserves and will not have accounted against subpool
1149 * limit. Check that the subpool limit can be made before
1150 * satisfying the allocation MAP_NORESERVE mappings may also
1151 * need pages and subpool limit allocated allocated if no reserve
1154 chg
= vma_needs_reservation(h
, vma
, addr
);
1156 return ERR_PTR(-ENOMEM
);
1158 if (hugepage_subpool_get_pages(spool
, chg
))
1159 return ERR_PTR(-ENOSPC
);
1161 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1163 hugepage_subpool_put_pages(spool
, chg
);
1164 return ERR_PTR(-ENOSPC
);
1166 spin_lock(&hugetlb_lock
);
1167 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1169 spin_unlock(&hugetlb_lock
);
1170 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1172 hugetlb_cgroup_uncharge_cgroup(idx
,
1173 pages_per_huge_page(h
),
1175 hugepage_subpool_put_pages(spool
, chg
);
1176 return ERR_PTR(-ENOSPC
);
1178 spin_lock(&hugetlb_lock
);
1179 list_move(&page
->lru
, &h
->hugepage_activelist
);
1182 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1183 spin_unlock(&hugetlb_lock
);
1185 set_page_private(page
, (unsigned long)spool
);
1187 vma_commit_reservation(h
, vma
, addr
);
1191 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1193 struct huge_bootmem_page
*m
;
1196 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1199 addr
= __alloc_bootmem_node_nopanic(NODE_DATA(node
),
1200 huge_page_size(h
), huge_page_size(h
), 0);
1204 * Use the beginning of the huge page to store the
1205 * huge_bootmem_page struct (until gather_bootmem
1206 * puts them into the mem_map).
1215 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1216 /* Put them into a private list first because mem_map is not up yet */
1217 list_add(&m
->list
, &huge_boot_pages
);
1222 static void prep_compound_huge_page(struct page
*page
, int order
)
1224 if (unlikely(order
> (MAX_ORDER
- 1)))
1225 prep_compound_gigantic_page(page
, order
);
1227 prep_compound_page(page
, order
);
1230 /* Put bootmem huge pages into the standard lists after mem_map is up */
1231 static void __init
gather_bootmem_prealloc(void)
1233 struct huge_bootmem_page
*m
;
1235 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1236 struct hstate
*h
= m
->hstate
;
1239 #ifdef CONFIG_HIGHMEM
1240 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1241 free_bootmem_late((unsigned long)m
,
1242 sizeof(struct huge_bootmem_page
));
1244 page
= virt_to_page(m
);
1246 __ClearPageReserved(page
);
1247 WARN_ON(page_count(page
) != 1);
1248 prep_compound_huge_page(page
, h
->order
);
1249 prep_new_huge_page(h
, page
, page_to_nid(page
));
1251 * If we had gigantic hugepages allocated at boot time, we need
1252 * to restore the 'stolen' pages to totalram_pages in order to
1253 * fix confusing memory reports from free(1) and another
1254 * side-effects, like CommitLimit going negative.
1256 if (h
->order
> (MAX_ORDER
- 1))
1257 adjust_managed_page_count(page
, 1 << h
->order
);
1261 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1265 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1266 if (h
->order
>= MAX_ORDER
) {
1267 if (!alloc_bootmem_huge_page(h
))
1269 } else if (!alloc_fresh_huge_page(h
,
1270 &node_states
[N_MEMORY
]))
1273 h
->max_huge_pages
= i
;
1276 static void __init
hugetlb_init_hstates(void)
1280 for_each_hstate(h
) {
1281 /* oversize hugepages were init'ed in early boot */
1282 if (h
->order
< MAX_ORDER
)
1283 hugetlb_hstate_alloc_pages(h
);
1287 static char * __init
memfmt(char *buf
, unsigned long n
)
1289 if (n
>= (1UL << 30))
1290 sprintf(buf
, "%lu GB", n
>> 30);
1291 else if (n
>= (1UL << 20))
1292 sprintf(buf
, "%lu MB", n
>> 20);
1294 sprintf(buf
, "%lu KB", n
>> 10);
1298 static void __init
report_hugepages(void)
1302 for_each_hstate(h
) {
1304 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1305 memfmt(buf
, huge_page_size(h
)),
1306 h
->free_huge_pages
);
1310 #ifdef CONFIG_HIGHMEM
1311 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1312 nodemask_t
*nodes_allowed
)
1316 if (h
->order
>= MAX_ORDER
)
1319 for_each_node_mask(i
, *nodes_allowed
) {
1320 struct page
*page
, *next
;
1321 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1322 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1323 if (count
>= h
->nr_huge_pages
)
1325 if (PageHighMem(page
))
1327 list_del(&page
->lru
);
1328 update_and_free_page(h
, page
);
1329 h
->free_huge_pages
--;
1330 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1335 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1336 nodemask_t
*nodes_allowed
)
1342 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1343 * balanced by operating on them in a round-robin fashion.
1344 * Returns 1 if an adjustment was made.
1346 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1351 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1354 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1355 if (h
->surplus_huge_pages_node
[node
])
1359 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1360 if (h
->surplus_huge_pages_node
[node
] <
1361 h
->nr_huge_pages_node
[node
])
1368 h
->surplus_huge_pages
+= delta
;
1369 h
->surplus_huge_pages_node
[node
] += delta
;
1373 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1374 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1375 nodemask_t
*nodes_allowed
)
1377 unsigned long min_count
, ret
;
1379 if (h
->order
>= MAX_ORDER
)
1380 return h
->max_huge_pages
;
1383 * Increase the pool size
1384 * First take pages out of surplus state. Then make up the
1385 * remaining difference by allocating fresh huge pages.
1387 * We might race with alloc_buddy_huge_page() here and be unable
1388 * to convert a surplus huge page to a normal huge page. That is
1389 * not critical, though, it just means the overall size of the
1390 * pool might be one hugepage larger than it needs to be, but
1391 * within all the constraints specified by the sysctls.
1393 spin_lock(&hugetlb_lock
);
1394 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1395 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1399 while (count
> persistent_huge_pages(h
)) {
1401 * If this allocation races such that we no longer need the
1402 * page, free_huge_page will handle it by freeing the page
1403 * and reducing the surplus.
1405 spin_unlock(&hugetlb_lock
);
1406 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1407 spin_lock(&hugetlb_lock
);
1411 /* Bail for signals. Probably ctrl-c from user */
1412 if (signal_pending(current
))
1417 * Decrease the pool size
1418 * First return free pages to the buddy allocator (being careful
1419 * to keep enough around to satisfy reservations). Then place
1420 * pages into surplus state as needed so the pool will shrink
1421 * to the desired size as pages become free.
1423 * By placing pages into the surplus state independent of the
1424 * overcommit value, we are allowing the surplus pool size to
1425 * exceed overcommit. There are few sane options here. Since
1426 * alloc_buddy_huge_page() is checking the global counter,
1427 * though, we'll note that we're not allowed to exceed surplus
1428 * and won't grow the pool anywhere else. Not until one of the
1429 * sysctls are changed, or the surplus pages go out of use.
1431 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1432 min_count
= max(count
, min_count
);
1433 try_to_free_low(h
, min_count
, nodes_allowed
);
1434 while (min_count
< persistent_huge_pages(h
)) {
1435 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1438 while (count
< persistent_huge_pages(h
)) {
1439 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1443 ret
= persistent_huge_pages(h
);
1444 spin_unlock(&hugetlb_lock
);
1448 #define HSTATE_ATTR_RO(_name) \
1449 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1451 #define HSTATE_ATTR(_name) \
1452 static struct kobj_attribute _name##_attr = \
1453 __ATTR(_name, 0644, _name##_show, _name##_store)
1455 static struct kobject
*hugepages_kobj
;
1456 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1458 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1460 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1464 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1465 if (hstate_kobjs
[i
] == kobj
) {
1467 *nidp
= NUMA_NO_NODE
;
1471 return kobj_to_node_hstate(kobj
, nidp
);
1474 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1475 struct kobj_attribute
*attr
, char *buf
)
1478 unsigned long nr_huge_pages
;
1481 h
= kobj_to_hstate(kobj
, &nid
);
1482 if (nid
== NUMA_NO_NODE
)
1483 nr_huge_pages
= h
->nr_huge_pages
;
1485 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1487 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1490 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1491 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1492 const char *buf
, size_t len
)
1496 unsigned long count
;
1498 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1500 err
= kstrtoul(buf
, 10, &count
);
1504 h
= kobj_to_hstate(kobj
, &nid
);
1505 if (h
->order
>= MAX_ORDER
) {
1510 if (nid
== NUMA_NO_NODE
) {
1512 * global hstate attribute
1514 if (!(obey_mempolicy
&&
1515 init_nodemask_of_mempolicy(nodes_allowed
))) {
1516 NODEMASK_FREE(nodes_allowed
);
1517 nodes_allowed
= &node_states
[N_MEMORY
];
1519 } else if (nodes_allowed
) {
1521 * per node hstate attribute: adjust count to global,
1522 * but restrict alloc/free to the specified node.
1524 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1525 init_nodemask_of_node(nodes_allowed
, nid
);
1527 nodes_allowed
= &node_states
[N_MEMORY
];
1529 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1531 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1532 NODEMASK_FREE(nodes_allowed
);
1536 NODEMASK_FREE(nodes_allowed
);
1540 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1541 struct kobj_attribute
*attr
, char *buf
)
1543 return nr_hugepages_show_common(kobj
, attr
, buf
);
1546 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1547 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1549 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1551 HSTATE_ATTR(nr_hugepages
);
1556 * hstate attribute for optionally mempolicy-based constraint on persistent
1557 * huge page alloc/free.
1559 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1560 struct kobj_attribute
*attr
, char *buf
)
1562 return nr_hugepages_show_common(kobj
, attr
, buf
);
1565 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1566 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1568 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1570 HSTATE_ATTR(nr_hugepages_mempolicy
);
1574 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1575 struct kobj_attribute
*attr
, char *buf
)
1577 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1578 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1581 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1582 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1585 unsigned long input
;
1586 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1588 if (h
->order
>= MAX_ORDER
)
1591 err
= kstrtoul(buf
, 10, &input
);
1595 spin_lock(&hugetlb_lock
);
1596 h
->nr_overcommit_huge_pages
= input
;
1597 spin_unlock(&hugetlb_lock
);
1601 HSTATE_ATTR(nr_overcommit_hugepages
);
1603 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1604 struct kobj_attribute
*attr
, char *buf
)
1607 unsigned long free_huge_pages
;
1610 h
= kobj_to_hstate(kobj
, &nid
);
1611 if (nid
== NUMA_NO_NODE
)
1612 free_huge_pages
= h
->free_huge_pages
;
1614 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1616 return sprintf(buf
, "%lu\n", free_huge_pages
);
1618 HSTATE_ATTR_RO(free_hugepages
);
1620 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1621 struct kobj_attribute
*attr
, char *buf
)
1623 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1624 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1626 HSTATE_ATTR_RO(resv_hugepages
);
1628 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1629 struct kobj_attribute
*attr
, char *buf
)
1632 unsigned long surplus_huge_pages
;
1635 h
= kobj_to_hstate(kobj
, &nid
);
1636 if (nid
== NUMA_NO_NODE
)
1637 surplus_huge_pages
= h
->surplus_huge_pages
;
1639 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1641 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1643 HSTATE_ATTR_RO(surplus_hugepages
);
1645 static struct attribute
*hstate_attrs
[] = {
1646 &nr_hugepages_attr
.attr
,
1647 &nr_overcommit_hugepages_attr
.attr
,
1648 &free_hugepages_attr
.attr
,
1649 &resv_hugepages_attr
.attr
,
1650 &surplus_hugepages_attr
.attr
,
1652 &nr_hugepages_mempolicy_attr
.attr
,
1657 static struct attribute_group hstate_attr_group
= {
1658 .attrs
= hstate_attrs
,
1661 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1662 struct kobject
**hstate_kobjs
,
1663 struct attribute_group
*hstate_attr_group
)
1666 int hi
= hstate_index(h
);
1668 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1669 if (!hstate_kobjs
[hi
])
1672 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1674 kobject_put(hstate_kobjs
[hi
]);
1679 static void __init
hugetlb_sysfs_init(void)
1684 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1685 if (!hugepages_kobj
)
1688 for_each_hstate(h
) {
1689 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1690 hstate_kobjs
, &hstate_attr_group
);
1692 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1699 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1700 * with node devices in node_devices[] using a parallel array. The array
1701 * index of a node device or _hstate == node id.
1702 * This is here to avoid any static dependency of the node device driver, in
1703 * the base kernel, on the hugetlb module.
1705 struct node_hstate
{
1706 struct kobject
*hugepages_kobj
;
1707 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1709 struct node_hstate node_hstates
[MAX_NUMNODES
];
1712 * A subset of global hstate attributes for node devices
1714 static struct attribute
*per_node_hstate_attrs
[] = {
1715 &nr_hugepages_attr
.attr
,
1716 &free_hugepages_attr
.attr
,
1717 &surplus_hugepages_attr
.attr
,
1721 static struct attribute_group per_node_hstate_attr_group
= {
1722 .attrs
= per_node_hstate_attrs
,
1726 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1727 * Returns node id via non-NULL nidp.
1729 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1733 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1734 struct node_hstate
*nhs
= &node_hstates
[nid
];
1736 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1737 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1749 * Unregister hstate attributes from a single node device.
1750 * No-op if no hstate attributes attached.
1752 static void hugetlb_unregister_node(struct node
*node
)
1755 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1757 if (!nhs
->hugepages_kobj
)
1758 return; /* no hstate attributes */
1760 for_each_hstate(h
) {
1761 int idx
= hstate_index(h
);
1762 if (nhs
->hstate_kobjs
[idx
]) {
1763 kobject_put(nhs
->hstate_kobjs
[idx
]);
1764 nhs
->hstate_kobjs
[idx
] = NULL
;
1768 kobject_put(nhs
->hugepages_kobj
);
1769 nhs
->hugepages_kobj
= NULL
;
1773 * hugetlb module exit: unregister hstate attributes from node devices
1776 static void hugetlb_unregister_all_nodes(void)
1781 * disable node device registrations.
1783 register_hugetlbfs_with_node(NULL
, NULL
);
1786 * remove hstate attributes from any nodes that have them.
1788 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1789 hugetlb_unregister_node(node_devices
[nid
]);
1793 * Register hstate attributes for a single node device.
1794 * No-op if attributes already registered.
1796 static void hugetlb_register_node(struct node
*node
)
1799 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1802 if (nhs
->hugepages_kobj
)
1803 return; /* already allocated */
1805 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1807 if (!nhs
->hugepages_kobj
)
1810 for_each_hstate(h
) {
1811 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1813 &per_node_hstate_attr_group
);
1815 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1816 h
->name
, node
->dev
.id
);
1817 hugetlb_unregister_node(node
);
1824 * hugetlb init time: register hstate attributes for all registered node
1825 * devices of nodes that have memory. All on-line nodes should have
1826 * registered their associated device by this time.
1828 static void hugetlb_register_all_nodes(void)
1832 for_each_node_state(nid
, N_MEMORY
) {
1833 struct node
*node
= node_devices
[nid
];
1834 if (node
->dev
.id
== nid
)
1835 hugetlb_register_node(node
);
1839 * Let the node device driver know we're here so it can
1840 * [un]register hstate attributes on node hotplug.
1842 register_hugetlbfs_with_node(hugetlb_register_node
,
1843 hugetlb_unregister_node
);
1845 #else /* !CONFIG_NUMA */
1847 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1855 static void hugetlb_unregister_all_nodes(void) { }
1857 static void hugetlb_register_all_nodes(void) { }
1861 static void __exit
hugetlb_exit(void)
1865 hugetlb_unregister_all_nodes();
1867 for_each_hstate(h
) {
1868 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1871 kobject_put(hugepages_kobj
);
1873 module_exit(hugetlb_exit
);
1875 static int __init
hugetlb_init(void)
1877 /* Some platform decide whether they support huge pages at boot
1878 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1879 * there is no such support
1881 if (HPAGE_SHIFT
== 0)
1884 if (!size_to_hstate(default_hstate_size
)) {
1885 default_hstate_size
= HPAGE_SIZE
;
1886 if (!size_to_hstate(default_hstate_size
))
1887 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1889 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1890 if (default_hstate_max_huge_pages
)
1891 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1893 hugetlb_init_hstates();
1894 gather_bootmem_prealloc();
1897 hugetlb_sysfs_init();
1898 hugetlb_register_all_nodes();
1899 hugetlb_cgroup_file_init();
1903 module_init(hugetlb_init
);
1905 /* Should be called on processing a hugepagesz=... option */
1906 void __init
hugetlb_add_hstate(unsigned order
)
1911 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1912 pr_warning("hugepagesz= specified twice, ignoring\n");
1915 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1917 h
= &hstates
[hugetlb_max_hstate
++];
1919 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1920 h
->nr_huge_pages
= 0;
1921 h
->free_huge_pages
= 0;
1922 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1923 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1924 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1925 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
1926 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
1927 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1928 huge_page_size(h
)/1024);
1933 static int __init
hugetlb_nrpages_setup(char *s
)
1936 static unsigned long *last_mhp
;
1939 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1940 * so this hugepages= parameter goes to the "default hstate".
1942 if (!hugetlb_max_hstate
)
1943 mhp
= &default_hstate_max_huge_pages
;
1945 mhp
= &parsed_hstate
->max_huge_pages
;
1947 if (mhp
== last_mhp
) {
1948 pr_warning("hugepages= specified twice without "
1949 "interleaving hugepagesz=, ignoring\n");
1953 if (sscanf(s
, "%lu", mhp
) <= 0)
1957 * Global state is always initialized later in hugetlb_init.
1958 * But we need to allocate >= MAX_ORDER hstates here early to still
1959 * use the bootmem allocator.
1961 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1962 hugetlb_hstate_alloc_pages(parsed_hstate
);
1968 __setup("hugepages=", hugetlb_nrpages_setup
);
1970 static int __init
hugetlb_default_setup(char *s
)
1972 default_hstate_size
= memparse(s
, &s
);
1975 __setup("default_hugepagesz=", hugetlb_default_setup
);
1977 static unsigned int cpuset_mems_nr(unsigned int *array
)
1980 unsigned int nr
= 0;
1982 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1988 #ifdef CONFIG_SYSCTL
1989 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1990 struct ctl_table
*table
, int write
,
1991 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1993 struct hstate
*h
= &default_hstate
;
1997 tmp
= h
->max_huge_pages
;
1999 if (write
&& h
->order
>= MAX_ORDER
)
2003 table
->maxlen
= sizeof(unsigned long);
2004 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2009 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2010 GFP_KERNEL
| __GFP_NORETRY
);
2011 if (!(obey_mempolicy
&&
2012 init_nodemask_of_mempolicy(nodes_allowed
))) {
2013 NODEMASK_FREE(nodes_allowed
);
2014 nodes_allowed
= &node_states
[N_MEMORY
];
2016 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2018 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2019 NODEMASK_FREE(nodes_allowed
);
2025 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2026 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2029 return hugetlb_sysctl_handler_common(false, table
, write
,
2030 buffer
, length
, ppos
);
2034 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2035 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2037 return hugetlb_sysctl_handler_common(true, table
, write
,
2038 buffer
, length
, ppos
);
2040 #endif /* CONFIG_NUMA */
2042 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2043 void __user
*buffer
,
2044 size_t *length
, loff_t
*ppos
)
2046 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2047 if (hugepages_treat_as_movable
)
2048 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2050 htlb_alloc_mask
= GFP_HIGHUSER
;
2054 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2055 void __user
*buffer
,
2056 size_t *length
, loff_t
*ppos
)
2058 struct hstate
*h
= &default_hstate
;
2062 tmp
= h
->nr_overcommit_huge_pages
;
2064 if (write
&& h
->order
>= MAX_ORDER
)
2068 table
->maxlen
= sizeof(unsigned long);
2069 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2074 spin_lock(&hugetlb_lock
);
2075 h
->nr_overcommit_huge_pages
= tmp
;
2076 spin_unlock(&hugetlb_lock
);
2082 #endif /* CONFIG_SYSCTL */
2084 void hugetlb_report_meminfo(struct seq_file
*m
)
2086 struct hstate
*h
= &default_hstate
;
2088 "HugePages_Total: %5lu\n"
2089 "HugePages_Free: %5lu\n"
2090 "HugePages_Rsvd: %5lu\n"
2091 "HugePages_Surp: %5lu\n"
2092 "Hugepagesize: %8lu kB\n",
2096 h
->surplus_huge_pages
,
2097 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2100 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2102 struct hstate
*h
= &default_hstate
;
2104 "Node %d HugePages_Total: %5u\n"
2105 "Node %d HugePages_Free: %5u\n"
2106 "Node %d HugePages_Surp: %5u\n",
2107 nid
, h
->nr_huge_pages_node
[nid
],
2108 nid
, h
->free_huge_pages_node
[nid
],
2109 nid
, h
->surplus_huge_pages_node
[nid
]);
2112 void hugetlb_show_meminfo(void)
2117 for_each_node_state(nid
, N_MEMORY
)
2119 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2121 h
->nr_huge_pages_node
[nid
],
2122 h
->free_huge_pages_node
[nid
],
2123 h
->surplus_huge_pages_node
[nid
],
2124 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2127 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2128 unsigned long hugetlb_total_pages(void)
2131 unsigned long nr_total_pages
= 0;
2134 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2135 return nr_total_pages
;
2138 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2142 spin_lock(&hugetlb_lock
);
2144 * When cpuset is configured, it breaks the strict hugetlb page
2145 * reservation as the accounting is done on a global variable. Such
2146 * reservation is completely rubbish in the presence of cpuset because
2147 * the reservation is not checked against page availability for the
2148 * current cpuset. Application can still potentially OOM'ed by kernel
2149 * with lack of free htlb page in cpuset that the task is in.
2150 * Attempt to enforce strict accounting with cpuset is almost
2151 * impossible (or too ugly) because cpuset is too fluid that
2152 * task or memory node can be dynamically moved between cpusets.
2154 * The change of semantics for shared hugetlb mapping with cpuset is
2155 * undesirable. However, in order to preserve some of the semantics,
2156 * we fall back to check against current free page availability as
2157 * a best attempt and hopefully to minimize the impact of changing
2158 * semantics that cpuset has.
2161 if (gather_surplus_pages(h
, delta
) < 0)
2164 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2165 return_unused_surplus_pages(h
, delta
);
2172 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2175 spin_unlock(&hugetlb_lock
);
2179 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2181 struct resv_map
*reservations
= vma_resv_map(vma
);
2184 * This new VMA should share its siblings reservation map if present.
2185 * The VMA will only ever have a valid reservation map pointer where
2186 * it is being copied for another still existing VMA. As that VMA
2187 * has a reference to the reservation map it cannot disappear until
2188 * after this open call completes. It is therefore safe to take a
2189 * new reference here without additional locking.
2192 kref_get(&reservations
->refs
);
2195 static void resv_map_put(struct vm_area_struct
*vma
)
2197 struct resv_map
*reservations
= vma_resv_map(vma
);
2201 kref_put(&reservations
->refs
, resv_map_release
);
2204 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2206 struct hstate
*h
= hstate_vma(vma
);
2207 struct resv_map
*reservations
= vma_resv_map(vma
);
2208 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2209 unsigned long reserve
;
2210 unsigned long start
;
2214 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2215 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2217 reserve
= (end
- start
) -
2218 region_count(&reservations
->regions
, start
, end
);
2223 hugetlb_acct_memory(h
, -reserve
);
2224 hugepage_subpool_put_pages(spool
, reserve
);
2230 * We cannot handle pagefaults against hugetlb pages at all. They cause
2231 * handle_mm_fault() to try to instantiate regular-sized pages in the
2232 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2235 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2241 const struct vm_operations_struct hugetlb_vm_ops
= {
2242 .fault
= hugetlb_vm_op_fault
,
2243 .open
= hugetlb_vm_op_open
,
2244 .close
= hugetlb_vm_op_close
,
2247 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2253 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2254 vma
->vm_page_prot
)));
2256 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2257 vma
->vm_page_prot
));
2259 entry
= pte_mkyoung(entry
);
2260 entry
= pte_mkhuge(entry
);
2261 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2266 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2267 unsigned long address
, pte_t
*ptep
)
2271 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2272 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2273 update_mmu_cache(vma
, address
, ptep
);
2277 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2278 struct vm_area_struct
*vma
)
2280 pte_t
*src_pte
, *dst_pte
, entry
;
2281 struct page
*ptepage
;
2284 struct hstate
*h
= hstate_vma(vma
);
2285 unsigned long sz
= huge_page_size(h
);
2287 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2289 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2290 src_pte
= huge_pte_offset(src
, addr
);
2293 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2297 /* If the pagetables are shared don't copy or take references */
2298 if (dst_pte
== src_pte
)
2301 spin_lock(&dst
->page_table_lock
);
2302 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2303 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2305 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2306 entry
= huge_ptep_get(src_pte
);
2307 ptepage
= pte_page(entry
);
2309 page_dup_rmap(ptepage
);
2310 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2312 spin_unlock(&src
->page_table_lock
);
2313 spin_unlock(&dst
->page_table_lock
);
2321 static int is_hugetlb_entry_migration(pte_t pte
)
2325 if (huge_pte_none(pte
) || pte_present(pte
))
2327 swp
= pte_to_swp_entry(pte
);
2328 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2334 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2338 if (huge_pte_none(pte
) || pte_present(pte
))
2340 swp
= pte_to_swp_entry(pte
);
2341 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2347 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2348 unsigned long start
, unsigned long end
,
2349 struct page
*ref_page
)
2351 int force_flush
= 0;
2352 struct mm_struct
*mm
= vma
->vm_mm
;
2353 unsigned long address
;
2357 struct hstate
*h
= hstate_vma(vma
);
2358 unsigned long sz
= huge_page_size(h
);
2359 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2360 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2362 WARN_ON(!is_vm_hugetlb_page(vma
));
2363 BUG_ON(start
& ~huge_page_mask(h
));
2364 BUG_ON(end
& ~huge_page_mask(h
));
2366 tlb_start_vma(tlb
, vma
);
2367 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2369 spin_lock(&mm
->page_table_lock
);
2370 for (address
= start
; address
< end
; address
+= sz
) {
2371 ptep
= huge_pte_offset(mm
, address
);
2375 if (huge_pmd_unshare(mm
, &address
, ptep
))
2378 pte
= huge_ptep_get(ptep
);
2379 if (huge_pte_none(pte
))
2383 * HWPoisoned hugepage is already unmapped and dropped reference
2385 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2386 huge_pte_clear(mm
, address
, ptep
);
2390 page
= pte_page(pte
);
2392 * If a reference page is supplied, it is because a specific
2393 * page is being unmapped, not a range. Ensure the page we
2394 * are about to unmap is the actual page of interest.
2397 if (page
!= ref_page
)
2401 * Mark the VMA as having unmapped its page so that
2402 * future faults in this VMA will fail rather than
2403 * looking like data was lost
2405 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2408 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2409 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2410 if (huge_pte_dirty(pte
))
2411 set_page_dirty(page
);
2413 page_remove_rmap(page
);
2414 force_flush
= !__tlb_remove_page(tlb
, page
);
2417 /* Bail out after unmapping reference page if supplied */
2421 spin_unlock(&mm
->page_table_lock
);
2423 * mmu_gather ran out of room to batch pages, we break out of
2424 * the PTE lock to avoid doing the potential expensive TLB invalidate
2425 * and page-free while holding it.
2430 if (address
< end
&& !ref_page
)
2433 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2434 tlb_end_vma(tlb
, vma
);
2437 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2438 struct vm_area_struct
*vma
, unsigned long start
,
2439 unsigned long end
, struct page
*ref_page
)
2441 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2444 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2445 * test will fail on a vma being torn down, and not grab a page table
2446 * on its way out. We're lucky that the flag has such an appropriate
2447 * name, and can in fact be safely cleared here. We could clear it
2448 * before the __unmap_hugepage_range above, but all that's necessary
2449 * is to clear it before releasing the i_mmap_mutex. This works
2450 * because in the context this is called, the VMA is about to be
2451 * destroyed and the i_mmap_mutex is held.
2453 vma
->vm_flags
&= ~VM_MAYSHARE
;
2456 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2457 unsigned long end
, struct page
*ref_page
)
2459 struct mm_struct
*mm
;
2460 struct mmu_gather tlb
;
2464 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2465 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2466 tlb_finish_mmu(&tlb
, start
, end
);
2470 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2471 * mappping it owns the reserve page for. The intention is to unmap the page
2472 * from other VMAs and let the children be SIGKILLed if they are faulting the
2475 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2476 struct page
*page
, unsigned long address
)
2478 struct hstate
*h
= hstate_vma(vma
);
2479 struct vm_area_struct
*iter_vma
;
2480 struct address_space
*mapping
;
2484 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2485 * from page cache lookup which is in HPAGE_SIZE units.
2487 address
= address
& huge_page_mask(h
);
2488 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2490 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2493 * Take the mapping lock for the duration of the table walk. As
2494 * this mapping should be shared between all the VMAs,
2495 * __unmap_hugepage_range() is called as the lock is already held
2497 mutex_lock(&mapping
->i_mmap_mutex
);
2498 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2499 /* Do not unmap the current VMA */
2500 if (iter_vma
== vma
)
2504 * Unmap the page from other VMAs without their own reserves.
2505 * They get marked to be SIGKILLed if they fault in these
2506 * areas. This is because a future no-page fault on this VMA
2507 * could insert a zeroed page instead of the data existing
2508 * from the time of fork. This would look like data corruption
2510 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2511 unmap_hugepage_range(iter_vma
, address
,
2512 address
+ huge_page_size(h
), page
);
2514 mutex_unlock(&mapping
->i_mmap_mutex
);
2520 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2521 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2522 * cannot race with other handlers or page migration.
2523 * Keep the pte_same checks anyway to make transition from the mutex easier.
2525 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2526 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2527 struct page
*pagecache_page
)
2529 struct hstate
*h
= hstate_vma(vma
);
2530 struct page
*old_page
, *new_page
;
2532 int outside_reserve
= 0;
2533 unsigned long mmun_start
; /* For mmu_notifiers */
2534 unsigned long mmun_end
; /* For mmu_notifiers */
2536 old_page
= pte_page(pte
);
2539 /* If no-one else is actually using this page, avoid the copy
2540 * and just make the page writable */
2541 avoidcopy
= (page_mapcount(old_page
) == 1);
2543 if (PageAnon(old_page
))
2544 page_move_anon_rmap(old_page
, vma
, address
);
2545 set_huge_ptep_writable(vma
, address
, ptep
);
2550 * If the process that created a MAP_PRIVATE mapping is about to
2551 * perform a COW due to a shared page count, attempt to satisfy
2552 * the allocation without using the existing reserves. The pagecache
2553 * page is used to determine if the reserve at this address was
2554 * consumed or not. If reserves were used, a partial faulted mapping
2555 * at the time of fork() could consume its reserves on COW instead
2556 * of the full address range.
2558 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2559 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2560 old_page
!= pagecache_page
)
2561 outside_reserve
= 1;
2563 page_cache_get(old_page
);
2565 /* Drop page_table_lock as buddy allocator may be called */
2566 spin_unlock(&mm
->page_table_lock
);
2567 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2569 if (IS_ERR(new_page
)) {
2570 long err
= PTR_ERR(new_page
);
2571 page_cache_release(old_page
);
2574 * If a process owning a MAP_PRIVATE mapping fails to COW,
2575 * it is due to references held by a child and an insufficient
2576 * huge page pool. To guarantee the original mappers
2577 * reliability, unmap the page from child processes. The child
2578 * may get SIGKILLed if it later faults.
2580 if (outside_reserve
) {
2581 BUG_ON(huge_pte_none(pte
));
2582 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2583 BUG_ON(huge_pte_none(pte
));
2584 spin_lock(&mm
->page_table_lock
);
2585 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2586 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2587 goto retry_avoidcopy
;
2589 * race occurs while re-acquiring page_table_lock, and
2597 /* Caller expects lock to be held */
2598 spin_lock(&mm
->page_table_lock
);
2600 return VM_FAULT_OOM
;
2602 return VM_FAULT_SIGBUS
;
2606 * When the original hugepage is shared one, it does not have
2607 * anon_vma prepared.
2609 if (unlikely(anon_vma_prepare(vma
))) {
2610 page_cache_release(new_page
);
2611 page_cache_release(old_page
);
2612 /* Caller expects lock to be held */
2613 spin_lock(&mm
->page_table_lock
);
2614 return VM_FAULT_OOM
;
2617 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2618 pages_per_huge_page(h
));
2619 __SetPageUptodate(new_page
);
2621 mmun_start
= address
& huge_page_mask(h
);
2622 mmun_end
= mmun_start
+ huge_page_size(h
);
2623 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2625 * Retake the page_table_lock to check for racing updates
2626 * before the page tables are altered
2628 spin_lock(&mm
->page_table_lock
);
2629 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2630 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2632 huge_ptep_clear_flush(vma
, address
, ptep
);
2633 set_huge_pte_at(mm
, address
, ptep
,
2634 make_huge_pte(vma
, new_page
, 1));
2635 page_remove_rmap(old_page
);
2636 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2637 /* Make the old page be freed below */
2638 new_page
= old_page
;
2640 spin_unlock(&mm
->page_table_lock
);
2641 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2642 /* Caller expects lock to be held */
2643 spin_lock(&mm
->page_table_lock
);
2644 page_cache_release(new_page
);
2645 page_cache_release(old_page
);
2649 /* Return the pagecache page at a given address within a VMA */
2650 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2651 struct vm_area_struct
*vma
, unsigned long address
)
2653 struct address_space
*mapping
;
2656 mapping
= vma
->vm_file
->f_mapping
;
2657 idx
= vma_hugecache_offset(h
, vma
, address
);
2659 return find_lock_page(mapping
, idx
);
2663 * Return whether there is a pagecache page to back given address within VMA.
2664 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2666 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2667 struct vm_area_struct
*vma
, unsigned long address
)
2669 struct address_space
*mapping
;
2673 mapping
= vma
->vm_file
->f_mapping
;
2674 idx
= vma_hugecache_offset(h
, vma
, address
);
2676 page
= find_get_page(mapping
, idx
);
2679 return page
!= NULL
;
2682 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2683 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2685 struct hstate
*h
= hstate_vma(vma
);
2686 int ret
= VM_FAULT_SIGBUS
;
2691 struct address_space
*mapping
;
2695 * Currently, we are forced to kill the process in the event the
2696 * original mapper has unmapped pages from the child due to a failed
2697 * COW. Warn that such a situation has occurred as it may not be obvious
2699 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2700 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2705 mapping
= vma
->vm_file
->f_mapping
;
2706 idx
= vma_hugecache_offset(h
, vma
, address
);
2709 * Use page lock to guard against racing truncation
2710 * before we get page_table_lock.
2713 page
= find_lock_page(mapping
, idx
);
2715 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2718 page
= alloc_huge_page(vma
, address
, 0);
2720 ret
= PTR_ERR(page
);
2724 ret
= VM_FAULT_SIGBUS
;
2727 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2728 __SetPageUptodate(page
);
2730 if (vma
->vm_flags
& VM_MAYSHARE
) {
2732 struct inode
*inode
= mapping
->host
;
2734 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2742 spin_lock(&inode
->i_lock
);
2743 inode
->i_blocks
+= blocks_per_huge_page(h
);
2744 spin_unlock(&inode
->i_lock
);
2747 if (unlikely(anon_vma_prepare(vma
))) {
2749 goto backout_unlocked
;
2755 * If memory error occurs between mmap() and fault, some process
2756 * don't have hwpoisoned swap entry for errored virtual address.
2757 * So we need to block hugepage fault by PG_hwpoison bit check.
2759 if (unlikely(PageHWPoison(page
))) {
2760 ret
= VM_FAULT_HWPOISON
|
2761 VM_FAULT_SET_HINDEX(hstate_index(h
));
2762 goto backout_unlocked
;
2767 * If we are going to COW a private mapping later, we examine the
2768 * pending reservations for this page now. This will ensure that
2769 * any allocations necessary to record that reservation occur outside
2772 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2773 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2775 goto backout_unlocked
;
2778 spin_lock(&mm
->page_table_lock
);
2779 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2784 if (!huge_pte_none(huge_ptep_get(ptep
)))
2788 hugepage_add_new_anon_rmap(page
, vma
, address
);
2790 page_dup_rmap(page
);
2791 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2792 && (vma
->vm_flags
& VM_SHARED
)));
2793 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2795 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2796 /* Optimization, do the COW without a second fault */
2797 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2800 spin_unlock(&mm
->page_table_lock
);
2806 spin_unlock(&mm
->page_table_lock
);
2813 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2814 unsigned long address
, unsigned int flags
)
2819 struct page
*page
= NULL
;
2820 struct page
*pagecache_page
= NULL
;
2821 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2822 struct hstate
*h
= hstate_vma(vma
);
2824 address
&= huge_page_mask(h
);
2826 ptep
= huge_pte_offset(mm
, address
);
2828 entry
= huge_ptep_get(ptep
);
2829 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2830 migration_entry_wait_huge(mm
, ptep
);
2832 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2833 return VM_FAULT_HWPOISON_LARGE
|
2834 VM_FAULT_SET_HINDEX(hstate_index(h
));
2837 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2839 return VM_FAULT_OOM
;
2842 * Serialize hugepage allocation and instantiation, so that we don't
2843 * get spurious allocation failures if two CPUs race to instantiate
2844 * the same page in the page cache.
2846 mutex_lock(&hugetlb_instantiation_mutex
);
2847 entry
= huge_ptep_get(ptep
);
2848 if (huge_pte_none(entry
)) {
2849 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2856 * If we are going to COW the mapping later, we examine the pending
2857 * reservations for this page now. This will ensure that any
2858 * allocations necessary to record that reservation occur outside the
2859 * spinlock. For private mappings, we also lookup the pagecache
2860 * page now as it is used to determine if a reservation has been
2863 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
2864 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2869 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2870 pagecache_page
= hugetlbfs_pagecache_page(h
,
2875 * hugetlb_cow() requires page locks of pte_page(entry) and
2876 * pagecache_page, so here we need take the former one
2877 * when page != pagecache_page or !pagecache_page.
2878 * Note that locking order is always pagecache_page -> page,
2879 * so no worry about deadlock.
2881 page
= pte_page(entry
);
2883 if (page
!= pagecache_page
)
2886 spin_lock(&mm
->page_table_lock
);
2887 /* Check for a racing update before calling hugetlb_cow */
2888 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2889 goto out_page_table_lock
;
2892 if (flags
& FAULT_FLAG_WRITE
) {
2893 if (!huge_pte_write(entry
)) {
2894 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2896 goto out_page_table_lock
;
2898 entry
= huge_pte_mkdirty(entry
);
2900 entry
= pte_mkyoung(entry
);
2901 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2902 flags
& FAULT_FLAG_WRITE
))
2903 update_mmu_cache(vma
, address
, ptep
);
2905 out_page_table_lock
:
2906 spin_unlock(&mm
->page_table_lock
);
2908 if (pagecache_page
) {
2909 unlock_page(pagecache_page
);
2910 put_page(pagecache_page
);
2912 if (page
!= pagecache_page
)
2917 mutex_unlock(&hugetlb_instantiation_mutex
);
2922 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2923 struct page
**pages
, struct vm_area_struct
**vmas
,
2924 unsigned long *position
, unsigned long *nr_pages
,
2925 long i
, unsigned int flags
)
2927 unsigned long pfn_offset
;
2928 unsigned long vaddr
= *position
;
2929 unsigned long remainder
= *nr_pages
;
2930 struct hstate
*h
= hstate_vma(vma
);
2932 spin_lock(&mm
->page_table_lock
);
2933 while (vaddr
< vma
->vm_end
&& remainder
) {
2939 * Some archs (sparc64, sh*) have multiple pte_ts to
2940 * each hugepage. We have to make sure we get the
2941 * first, for the page indexing below to work.
2943 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2944 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2947 * When coredumping, it suits get_dump_page if we just return
2948 * an error where there's an empty slot with no huge pagecache
2949 * to back it. This way, we avoid allocating a hugepage, and
2950 * the sparse dumpfile avoids allocating disk blocks, but its
2951 * huge holes still show up with zeroes where they need to be.
2953 if (absent
&& (flags
& FOLL_DUMP
) &&
2954 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2960 * We need call hugetlb_fault for both hugepages under migration
2961 * (in which case hugetlb_fault waits for the migration,) and
2962 * hwpoisoned hugepages (in which case we need to prevent the
2963 * caller from accessing to them.) In order to do this, we use
2964 * here is_swap_pte instead of is_hugetlb_entry_migration and
2965 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
2966 * both cases, and because we can't follow correct pages
2967 * directly from any kind of swap entries.
2969 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
2970 ((flags
& FOLL_WRITE
) &&
2971 !huge_pte_write(huge_ptep_get(pte
)))) {
2974 spin_unlock(&mm
->page_table_lock
);
2975 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2976 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2977 spin_lock(&mm
->page_table_lock
);
2978 if (!(ret
& VM_FAULT_ERROR
))
2985 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2986 page
= pte_page(huge_ptep_get(pte
));
2989 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3000 if (vaddr
< vma
->vm_end
&& remainder
&&
3001 pfn_offset
< pages_per_huge_page(h
)) {
3003 * We use pfn_offset to avoid touching the pageframes
3004 * of this compound page.
3009 spin_unlock(&mm
->page_table_lock
);
3010 *nr_pages
= remainder
;
3013 return i
? i
: -EFAULT
;
3016 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3017 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3019 struct mm_struct
*mm
= vma
->vm_mm
;
3020 unsigned long start
= address
;
3023 struct hstate
*h
= hstate_vma(vma
);
3024 unsigned long pages
= 0;
3026 BUG_ON(address
>= end
);
3027 flush_cache_range(vma
, address
, end
);
3029 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3030 spin_lock(&mm
->page_table_lock
);
3031 for (; address
< end
; address
+= huge_page_size(h
)) {
3032 ptep
= huge_pte_offset(mm
, address
);
3035 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3039 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3040 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3041 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3042 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3043 set_huge_pte_at(mm
, address
, ptep
, pte
);
3047 spin_unlock(&mm
->page_table_lock
);
3049 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3050 * may have cleared our pud entry and done put_page on the page table:
3051 * once we release i_mmap_mutex, another task can do the final put_page
3052 * and that page table be reused and filled with junk.
3054 flush_tlb_range(vma
, start
, end
);
3055 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3057 return pages
<< h
->order
;
3060 int hugetlb_reserve_pages(struct inode
*inode
,
3062 struct vm_area_struct
*vma
,
3063 vm_flags_t vm_flags
)
3066 struct hstate
*h
= hstate_inode(inode
);
3067 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3070 * Only apply hugepage reservation if asked. At fault time, an
3071 * attempt will be made for VM_NORESERVE to allocate a page
3072 * without using reserves
3074 if (vm_flags
& VM_NORESERVE
)
3078 * Shared mappings base their reservation on the number of pages that
3079 * are already allocated on behalf of the file. Private mappings need
3080 * to reserve the full area even if read-only as mprotect() may be
3081 * called to make the mapping read-write. Assume !vma is a shm mapping
3083 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3084 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3086 struct resv_map
*resv_map
= resv_map_alloc();
3092 set_vma_resv_map(vma
, resv_map
);
3093 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3101 /* There must be enough pages in the subpool for the mapping */
3102 if (hugepage_subpool_get_pages(spool
, chg
)) {
3108 * Check enough hugepages are available for the reservation.
3109 * Hand the pages back to the subpool if there are not
3111 ret
= hugetlb_acct_memory(h
, chg
);
3113 hugepage_subpool_put_pages(spool
, chg
);
3118 * Account for the reservations made. Shared mappings record regions
3119 * that have reservations as they are shared by multiple VMAs.
3120 * When the last VMA disappears, the region map says how much
3121 * the reservation was and the page cache tells how much of
3122 * the reservation was consumed. Private mappings are per-VMA and
3123 * only the consumed reservations are tracked. When the VMA
3124 * disappears, the original reservation is the VMA size and the
3125 * consumed reservations are stored in the map. Hence, nothing
3126 * else has to be done for private mappings here
3128 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3129 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3137 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3139 struct hstate
*h
= hstate_inode(inode
);
3140 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3141 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3143 spin_lock(&inode
->i_lock
);
3144 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3145 spin_unlock(&inode
->i_lock
);
3147 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3148 hugetlb_acct_memory(h
, -(chg
- freed
));
3151 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3152 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3153 struct vm_area_struct
*vma
,
3154 unsigned long addr
, pgoff_t idx
)
3156 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3158 unsigned long sbase
= saddr
& PUD_MASK
;
3159 unsigned long s_end
= sbase
+ PUD_SIZE
;
3161 /* Allow segments to share if only one is marked locked */
3162 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3163 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3166 * match the virtual addresses, permission and the alignment of the
3169 if (pmd_index(addr
) != pmd_index(saddr
) ||
3170 vm_flags
!= svm_flags
||
3171 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3177 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3179 unsigned long base
= addr
& PUD_MASK
;
3180 unsigned long end
= base
+ PUD_SIZE
;
3183 * check on proper vm_flags and page table alignment
3185 if (vma
->vm_flags
& VM_MAYSHARE
&&
3186 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3192 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3193 * and returns the corresponding pte. While this is not necessary for the
3194 * !shared pmd case because we can allocate the pmd later as well, it makes the
3195 * code much cleaner. pmd allocation is essential for the shared case because
3196 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3197 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3198 * bad pmd for sharing.
3200 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3202 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3203 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3204 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3206 struct vm_area_struct
*svma
;
3207 unsigned long saddr
;
3211 if (!vma_shareable(vma
, addr
))
3212 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3214 mutex_lock(&mapping
->i_mmap_mutex
);
3215 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3219 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3221 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3223 get_page(virt_to_page(spte
));
3232 spin_lock(&mm
->page_table_lock
);
3234 pud_populate(mm
, pud
,
3235 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3237 put_page(virt_to_page(spte
));
3238 spin_unlock(&mm
->page_table_lock
);
3240 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3241 mutex_unlock(&mapping
->i_mmap_mutex
);
3246 * unmap huge page backed by shared pte.
3248 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3249 * indicated by page_count > 1, unmap is achieved by clearing pud and
3250 * decrementing the ref count. If count == 1, the pte page is not shared.
3252 * called with vma->vm_mm->page_table_lock held.
3254 * returns: 1 successfully unmapped a shared pte page
3255 * 0 the underlying pte page is not shared, or it is the last user
3257 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3259 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3260 pud_t
*pud
= pud_offset(pgd
, *addr
);
3262 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3263 if (page_count(virt_to_page(ptep
)) == 1)
3267 put_page(virt_to_page(ptep
));
3268 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3271 #define want_pmd_share() (1)
3272 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3273 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3277 #define want_pmd_share() (0)
3278 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3280 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3281 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3282 unsigned long addr
, unsigned long sz
)
3288 pgd
= pgd_offset(mm
, addr
);
3289 pud
= pud_alloc(mm
, pgd
, addr
);
3291 if (sz
== PUD_SIZE
) {
3294 BUG_ON(sz
!= PMD_SIZE
);
3295 if (want_pmd_share() && pud_none(*pud
))
3296 pte
= huge_pmd_share(mm
, addr
, pud
);
3298 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3301 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3306 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3312 pgd
= pgd_offset(mm
, addr
);
3313 if (pgd_present(*pgd
)) {
3314 pud
= pud_offset(pgd
, addr
);
3315 if (pud_present(*pud
)) {
3317 return (pte_t
*)pud
;
3318 pmd
= pmd_offset(pud
, addr
);
3321 return (pte_t
*) pmd
;
3325 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3326 pmd_t
*pmd
, int write
)
3330 page
= pte_page(*(pte_t
*)pmd
);
3332 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3337 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3338 pud_t
*pud
, int write
)
3342 page
= pte_page(*(pte_t
*)pud
);
3344 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3348 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3350 /* Can be overriden by architectures */
3351 __attribute__((weak
)) struct page
*
3352 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3353 pud_t
*pud
, int write
)
3359 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3361 #ifdef CONFIG_MEMORY_FAILURE
3363 /* Should be called in hugetlb_lock */
3364 static int is_hugepage_on_freelist(struct page
*hpage
)
3368 struct hstate
*h
= page_hstate(hpage
);
3369 int nid
= page_to_nid(hpage
);
3371 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3378 * This function is called from memory failure code.
3379 * Assume the caller holds page lock of the head page.
3381 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3383 struct hstate
*h
= page_hstate(hpage
);
3384 int nid
= page_to_nid(hpage
);
3387 spin_lock(&hugetlb_lock
);
3388 if (is_hugepage_on_freelist(hpage
)) {
3390 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3391 * but dangling hpage->lru can trigger list-debug warnings
3392 * (this happens when we call unpoison_memory() on it),
3393 * so let it point to itself with list_del_init().
3395 list_del_init(&hpage
->lru
);
3396 set_page_refcounted(hpage
);
3397 h
->free_huge_pages
--;
3398 h
->free_huge_pages_node
[nid
]--;
3401 spin_unlock(&hugetlb_lock
);