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 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
438 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
440 VM_BUG_ON(!is_vm_hugetlb_page(vma
));
441 if (!(vma
->vm_flags
& VM_MAYSHARE
))
442 vma
->vm_private_data
= (void *)0;
445 /* Returns true if the VMA has associated reserve pages */
446 static int vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
448 if (vma
->vm_flags
& VM_NORESERVE
) {
450 * This address is already reserved by other process(chg == 0),
451 * so, we should decrement reserved count. Without decrementing,
452 * reserve count remains after releasing inode, because this
453 * allocated page will go into page cache and is regarded as
454 * coming from reserved pool in releasing step. Currently, we
455 * don't have any other solution to deal with this situation
456 * properly, so add work-around here.
458 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
464 /* Shared mappings always use reserves */
465 if (vma
->vm_flags
& VM_MAYSHARE
)
469 * Only the process that called mmap() has reserves for
472 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
478 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
481 struct hstate
*h
= page_hstate(src
);
482 struct page
*dst_base
= dst
;
483 struct page
*src_base
= src
;
485 for (i
= 0; i
< pages_per_huge_page(h
); ) {
487 copy_highpage(dst
, src
);
490 dst
= mem_map_next(dst
, dst_base
, i
);
491 src
= mem_map_next(src
, src_base
, i
);
495 void copy_huge_page(struct page
*dst
, struct page
*src
)
498 struct hstate
*h
= page_hstate(src
);
500 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
501 copy_gigantic_page(dst
, src
);
506 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
508 copy_highpage(dst
+ i
, src
+ i
);
512 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
514 int nid
= page_to_nid(page
);
515 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
516 h
->free_huge_pages
++;
517 h
->free_huge_pages_node
[nid
]++;
520 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
524 if (list_empty(&h
->hugepage_freelists
[nid
]))
526 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
527 list_move(&page
->lru
, &h
->hugepage_activelist
);
528 set_page_refcounted(page
);
529 h
->free_huge_pages
--;
530 h
->free_huge_pages_node
[nid
]--;
534 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
535 struct vm_area_struct
*vma
,
536 unsigned long address
, int avoid_reserve
,
539 struct page
*page
= NULL
;
540 struct mempolicy
*mpol
;
541 nodemask_t
*nodemask
;
542 struct zonelist
*zonelist
;
545 unsigned int cpuset_mems_cookie
;
548 * A child process with MAP_PRIVATE mappings created by their parent
549 * have no page reserves. This check ensures that reservations are
550 * not "stolen". The child may still get SIGKILLed
552 if (!vma_has_reserves(vma
, chg
) &&
553 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
556 /* If reserves cannot be used, ensure enough pages are in the pool */
557 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
561 cpuset_mems_cookie
= get_mems_allowed();
562 zonelist
= huge_zonelist(vma
, address
,
563 htlb_alloc_mask
, &mpol
, &nodemask
);
565 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
566 MAX_NR_ZONES
- 1, nodemask
) {
567 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
568 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
572 if (!vma_has_reserves(vma
, chg
))
575 h
->resv_huge_pages
--;
582 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
590 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
594 VM_BUG_ON(h
->order
>= MAX_ORDER
);
597 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
598 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
599 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
600 1 << PG_referenced
| 1 << PG_dirty
|
601 1 << PG_active
| 1 << PG_reserved
|
602 1 << PG_private
| 1 << PG_writeback
);
604 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
605 set_compound_page_dtor(page
, NULL
);
606 set_page_refcounted(page
);
607 arch_release_hugepage(page
);
608 __free_pages(page
, huge_page_order(h
));
611 struct hstate
*size_to_hstate(unsigned long size
)
616 if (huge_page_size(h
) == size
)
622 static void free_huge_page(struct page
*page
)
625 * Can't pass hstate in here because it is called from the
626 * compound page destructor.
628 struct hstate
*h
= page_hstate(page
);
629 int nid
= page_to_nid(page
);
630 struct hugepage_subpool
*spool
=
631 (struct hugepage_subpool
*)page_private(page
);
633 set_page_private(page
, 0);
634 page
->mapping
= NULL
;
635 BUG_ON(page_count(page
));
636 BUG_ON(page_mapcount(page
));
638 spin_lock(&hugetlb_lock
);
639 hugetlb_cgroup_uncharge_page(hstate_index(h
),
640 pages_per_huge_page(h
), page
);
641 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
642 /* remove the page from active list */
643 list_del(&page
->lru
);
644 update_and_free_page(h
, page
);
645 h
->surplus_huge_pages
--;
646 h
->surplus_huge_pages_node
[nid
]--;
648 arch_clear_hugepage_flags(page
);
649 enqueue_huge_page(h
, page
);
651 spin_unlock(&hugetlb_lock
);
652 hugepage_subpool_put_pages(spool
, 1);
655 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
657 INIT_LIST_HEAD(&page
->lru
);
658 set_compound_page_dtor(page
, free_huge_page
);
659 spin_lock(&hugetlb_lock
);
660 set_hugetlb_cgroup(page
, NULL
);
662 h
->nr_huge_pages_node
[nid
]++;
663 spin_unlock(&hugetlb_lock
);
664 put_page(page
); /* free it into the hugepage allocator */
667 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
670 int nr_pages
= 1 << order
;
671 struct page
*p
= page
+ 1;
673 /* we rely on prep_new_huge_page to set the destructor */
674 set_compound_order(page
, order
);
676 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
678 set_page_count(p
, 0);
679 p
->first_page
= page
;
684 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
685 * transparent huge pages. See the PageTransHuge() documentation for more
688 int PageHuge(struct page
*page
)
690 compound_page_dtor
*dtor
;
692 if (!PageCompound(page
))
695 page
= compound_head(page
);
696 dtor
= get_compound_page_dtor(page
);
698 return dtor
== free_huge_page
;
700 EXPORT_SYMBOL_GPL(PageHuge
);
702 pgoff_t
__basepage_index(struct page
*page
)
704 struct page
*page_head
= compound_head(page
);
705 pgoff_t index
= page_index(page_head
);
706 unsigned long compound_idx
;
708 if (!PageHuge(page_head
))
709 return page_index(page
);
711 if (compound_order(page_head
) >= MAX_ORDER
)
712 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
714 compound_idx
= page
- page_head
;
716 return (index
<< compound_order(page_head
)) + compound_idx
;
719 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
723 if (h
->order
>= MAX_ORDER
)
726 page
= alloc_pages_exact_node(nid
,
727 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
728 __GFP_REPEAT
|__GFP_NOWARN
,
731 if (arch_prepare_hugepage(page
)) {
732 __free_pages(page
, huge_page_order(h
));
735 prep_new_huge_page(h
, page
, nid
);
742 * common helper functions for hstate_next_node_to_{alloc|free}.
743 * We may have allocated or freed a huge page based on a different
744 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
745 * be outside of *nodes_allowed. Ensure that we use an allowed
746 * node for alloc or free.
748 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
750 nid
= next_node(nid
, *nodes_allowed
);
751 if (nid
== MAX_NUMNODES
)
752 nid
= first_node(*nodes_allowed
);
753 VM_BUG_ON(nid
>= MAX_NUMNODES
);
758 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
760 if (!node_isset(nid
, *nodes_allowed
))
761 nid
= next_node_allowed(nid
, nodes_allowed
);
766 * returns the previously saved node ["this node"] from which to
767 * allocate a persistent huge page for the pool and advance the
768 * next node from which to allocate, handling wrap at end of node
771 static int hstate_next_node_to_alloc(struct hstate
*h
,
772 nodemask_t
*nodes_allowed
)
776 VM_BUG_ON(!nodes_allowed
);
778 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
779 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
785 * helper for free_pool_huge_page() - return the previously saved
786 * node ["this node"] from which to free a huge page. Advance the
787 * next node id whether or not we find a free huge page to free so
788 * that the next attempt to free addresses the next node.
790 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
794 VM_BUG_ON(!nodes_allowed
);
796 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
797 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
802 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
803 for (nr_nodes = nodes_weight(*mask); \
805 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
808 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
809 for (nr_nodes = nodes_weight(*mask); \
811 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
814 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
820 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
821 page
= alloc_fresh_huge_page_node(h
, node
);
829 count_vm_event(HTLB_BUDDY_PGALLOC
);
831 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
837 * Free huge page from pool from next node to free.
838 * Attempt to keep persistent huge pages more or less
839 * balanced over allowed nodes.
840 * Called with hugetlb_lock locked.
842 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
848 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
850 * If we're returning unused surplus pages, only examine
851 * nodes with surplus pages.
853 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
854 !list_empty(&h
->hugepage_freelists
[node
])) {
856 list_entry(h
->hugepage_freelists
[node
].next
,
858 list_del(&page
->lru
);
859 h
->free_huge_pages
--;
860 h
->free_huge_pages_node
[node
]--;
862 h
->surplus_huge_pages
--;
863 h
->surplus_huge_pages_node
[node
]--;
865 update_and_free_page(h
, page
);
874 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
879 if (h
->order
>= MAX_ORDER
)
883 * Assume we will successfully allocate the surplus page to
884 * prevent racing processes from causing the surplus to exceed
887 * This however introduces a different race, where a process B
888 * tries to grow the static hugepage pool while alloc_pages() is
889 * called by process A. B will only examine the per-node
890 * counters in determining if surplus huge pages can be
891 * converted to normal huge pages in adjust_pool_surplus(). A
892 * won't be able to increment the per-node counter, until the
893 * lock is dropped by B, but B doesn't drop hugetlb_lock until
894 * no more huge pages can be converted from surplus to normal
895 * state (and doesn't try to convert again). Thus, we have a
896 * case where a surplus huge page exists, the pool is grown, and
897 * the surplus huge page still exists after, even though it
898 * should just have been converted to a normal huge page. This
899 * does not leak memory, though, as the hugepage will be freed
900 * once it is out of use. It also does not allow the counters to
901 * go out of whack in adjust_pool_surplus() as we don't modify
902 * the node values until we've gotten the hugepage and only the
903 * per-node value is checked there.
905 spin_lock(&hugetlb_lock
);
906 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
907 spin_unlock(&hugetlb_lock
);
911 h
->surplus_huge_pages
++;
913 spin_unlock(&hugetlb_lock
);
915 if (nid
== NUMA_NO_NODE
)
916 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
917 __GFP_REPEAT
|__GFP_NOWARN
,
920 page
= alloc_pages_exact_node(nid
,
921 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
922 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
924 if (page
&& arch_prepare_hugepage(page
)) {
925 __free_pages(page
, huge_page_order(h
));
929 spin_lock(&hugetlb_lock
);
931 INIT_LIST_HEAD(&page
->lru
);
932 r_nid
= page_to_nid(page
);
933 set_compound_page_dtor(page
, free_huge_page
);
934 set_hugetlb_cgroup(page
, NULL
);
936 * We incremented the global counters already
938 h
->nr_huge_pages_node
[r_nid
]++;
939 h
->surplus_huge_pages_node
[r_nid
]++;
940 __count_vm_event(HTLB_BUDDY_PGALLOC
);
943 h
->surplus_huge_pages
--;
944 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
946 spin_unlock(&hugetlb_lock
);
952 * This allocation function is useful in the context where vma is irrelevant.
953 * E.g. soft-offlining uses this function because it only cares physical
954 * address of error page.
956 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
958 struct page
*page
= NULL
;
960 spin_lock(&hugetlb_lock
);
961 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
962 page
= dequeue_huge_page_node(h
, nid
);
963 spin_unlock(&hugetlb_lock
);
966 page
= alloc_buddy_huge_page(h
, nid
);
972 * Increase the hugetlb pool such that it can accommodate a reservation
975 static int gather_surplus_pages(struct hstate
*h
, int delta
)
977 struct list_head surplus_list
;
978 struct page
*page
, *tmp
;
980 int needed
, allocated
;
981 bool alloc_ok
= true;
983 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
985 h
->resv_huge_pages
+= delta
;
990 INIT_LIST_HEAD(&surplus_list
);
994 spin_unlock(&hugetlb_lock
);
995 for (i
= 0; i
< needed
; i
++) {
996 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1001 list_add(&page
->lru
, &surplus_list
);
1006 * After retaking hugetlb_lock, we need to recalculate 'needed'
1007 * because either resv_huge_pages or free_huge_pages may have changed.
1009 spin_lock(&hugetlb_lock
);
1010 needed
= (h
->resv_huge_pages
+ delta
) -
1011 (h
->free_huge_pages
+ allocated
);
1016 * We were not able to allocate enough pages to
1017 * satisfy the entire reservation so we free what
1018 * we've allocated so far.
1023 * The surplus_list now contains _at_least_ the number of extra pages
1024 * needed to accommodate the reservation. Add the appropriate number
1025 * of pages to the hugetlb pool and free the extras back to the buddy
1026 * allocator. Commit the entire reservation here to prevent another
1027 * process from stealing the pages as they are added to the pool but
1028 * before they are reserved.
1030 needed
+= allocated
;
1031 h
->resv_huge_pages
+= delta
;
1034 /* Free the needed pages to the hugetlb pool */
1035 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1039 * This page is now managed by the hugetlb allocator and has
1040 * no users -- drop the buddy allocator's reference.
1042 put_page_testzero(page
);
1043 VM_BUG_ON(page_count(page
));
1044 enqueue_huge_page(h
, page
);
1047 spin_unlock(&hugetlb_lock
);
1049 /* Free unnecessary surplus pages to the buddy allocator */
1050 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1052 spin_lock(&hugetlb_lock
);
1058 * When releasing a hugetlb pool reservation, any surplus pages that were
1059 * allocated to satisfy the reservation must be explicitly freed if they were
1061 * Called with hugetlb_lock held.
1063 static void return_unused_surplus_pages(struct hstate
*h
,
1064 unsigned long unused_resv_pages
)
1066 unsigned long nr_pages
;
1068 /* Uncommit the reservation */
1069 h
->resv_huge_pages
-= unused_resv_pages
;
1071 /* Cannot return gigantic pages currently */
1072 if (h
->order
>= MAX_ORDER
)
1075 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1078 * We want to release as many surplus pages as possible, spread
1079 * evenly across all nodes with memory. Iterate across these nodes
1080 * until we can no longer free unreserved surplus pages. This occurs
1081 * when the nodes with surplus pages have no free pages.
1082 * free_pool_huge_page() will balance the the freed pages across the
1083 * on-line nodes with memory and will handle the hstate accounting.
1085 while (nr_pages
--) {
1086 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1092 * Determine if the huge page at addr within the vma has an associated
1093 * reservation. Where it does not we will need to logically increase
1094 * reservation and actually increase subpool usage before an allocation
1095 * can occur. Where any new reservation would be required the
1096 * reservation change is prepared, but not committed. Once the page
1097 * has been allocated from the subpool and instantiated the change should
1098 * be committed via vma_commit_reservation. No action is required on
1101 static long vma_needs_reservation(struct hstate
*h
,
1102 struct vm_area_struct
*vma
, unsigned long addr
)
1104 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1105 struct inode
*inode
= mapping
->host
;
1107 if (vma
->vm_flags
& VM_MAYSHARE
) {
1108 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1109 return region_chg(&inode
->i_mapping
->private_list
,
1112 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1117 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1118 struct resv_map
*resv
= vma_resv_map(vma
);
1120 err
= region_chg(&resv
->regions
, idx
, idx
+ 1);
1126 static void vma_commit_reservation(struct hstate
*h
,
1127 struct vm_area_struct
*vma
, unsigned long addr
)
1129 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1130 struct inode
*inode
= mapping
->host
;
1132 if (vma
->vm_flags
& VM_MAYSHARE
) {
1133 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1134 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1136 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1137 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1138 struct resv_map
*resv
= vma_resv_map(vma
);
1140 /* Mark this page used in the map. */
1141 region_add(&resv
->regions
, idx
, idx
+ 1);
1145 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1146 unsigned long addr
, int avoid_reserve
)
1148 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1149 struct hstate
*h
= hstate_vma(vma
);
1153 struct hugetlb_cgroup
*h_cg
;
1155 idx
= hstate_index(h
);
1157 * Processes that did not create the mapping will have no
1158 * reserves and will not have accounted against subpool
1159 * limit. Check that the subpool limit can be made before
1160 * satisfying the allocation MAP_NORESERVE mappings may also
1161 * need pages and subpool limit allocated allocated if no reserve
1164 chg
= vma_needs_reservation(h
, vma
, addr
);
1166 return ERR_PTR(-ENOMEM
);
1168 if (hugepage_subpool_get_pages(spool
, chg
))
1169 return ERR_PTR(-ENOSPC
);
1171 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1173 hugepage_subpool_put_pages(spool
, chg
);
1174 return ERR_PTR(-ENOSPC
);
1176 spin_lock(&hugetlb_lock
);
1177 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, chg
);
1179 spin_unlock(&hugetlb_lock
);
1180 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1182 hugetlb_cgroup_uncharge_cgroup(idx
,
1183 pages_per_huge_page(h
),
1185 hugepage_subpool_put_pages(spool
, chg
);
1186 return ERR_PTR(-ENOSPC
);
1188 spin_lock(&hugetlb_lock
);
1189 list_move(&page
->lru
, &h
->hugepage_activelist
);
1192 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1193 spin_unlock(&hugetlb_lock
);
1195 set_page_private(page
, (unsigned long)spool
);
1197 vma_commit_reservation(h
, vma
, addr
);
1201 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1203 struct huge_bootmem_page
*m
;
1206 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1209 addr
= __alloc_bootmem_node_nopanic(NODE_DATA(node
),
1210 huge_page_size(h
), huge_page_size(h
), 0);
1214 * Use the beginning of the huge page to store the
1215 * huge_bootmem_page struct (until gather_bootmem
1216 * puts them into the mem_map).
1225 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1226 /* Put them into a private list first because mem_map is not up yet */
1227 list_add(&m
->list
, &huge_boot_pages
);
1232 static void prep_compound_huge_page(struct page
*page
, int order
)
1234 if (unlikely(order
> (MAX_ORDER
- 1)))
1235 prep_compound_gigantic_page(page
, order
);
1237 prep_compound_page(page
, order
);
1240 /* Put bootmem huge pages into the standard lists after mem_map is up */
1241 static void __init
gather_bootmem_prealloc(void)
1243 struct huge_bootmem_page
*m
;
1245 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1246 struct hstate
*h
= m
->hstate
;
1249 #ifdef CONFIG_HIGHMEM
1250 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1251 free_bootmem_late((unsigned long)m
,
1252 sizeof(struct huge_bootmem_page
));
1254 page
= virt_to_page(m
);
1256 __ClearPageReserved(page
);
1257 WARN_ON(page_count(page
) != 1);
1258 prep_compound_huge_page(page
, h
->order
);
1259 prep_new_huge_page(h
, page
, page_to_nid(page
));
1261 * If we had gigantic hugepages allocated at boot time, we need
1262 * to restore the 'stolen' pages to totalram_pages in order to
1263 * fix confusing memory reports from free(1) and another
1264 * side-effects, like CommitLimit going negative.
1266 if (h
->order
> (MAX_ORDER
- 1))
1267 adjust_managed_page_count(page
, 1 << h
->order
);
1271 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1275 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1276 if (h
->order
>= MAX_ORDER
) {
1277 if (!alloc_bootmem_huge_page(h
))
1279 } else if (!alloc_fresh_huge_page(h
,
1280 &node_states
[N_MEMORY
]))
1283 h
->max_huge_pages
= i
;
1286 static void __init
hugetlb_init_hstates(void)
1290 for_each_hstate(h
) {
1291 /* oversize hugepages were init'ed in early boot */
1292 if (h
->order
< MAX_ORDER
)
1293 hugetlb_hstate_alloc_pages(h
);
1297 static char * __init
memfmt(char *buf
, unsigned long n
)
1299 if (n
>= (1UL << 30))
1300 sprintf(buf
, "%lu GB", n
>> 30);
1301 else if (n
>= (1UL << 20))
1302 sprintf(buf
, "%lu MB", n
>> 20);
1304 sprintf(buf
, "%lu KB", n
>> 10);
1308 static void __init
report_hugepages(void)
1312 for_each_hstate(h
) {
1314 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1315 memfmt(buf
, huge_page_size(h
)),
1316 h
->free_huge_pages
);
1320 #ifdef CONFIG_HIGHMEM
1321 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1322 nodemask_t
*nodes_allowed
)
1326 if (h
->order
>= MAX_ORDER
)
1329 for_each_node_mask(i
, *nodes_allowed
) {
1330 struct page
*page
, *next
;
1331 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1332 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1333 if (count
>= h
->nr_huge_pages
)
1335 if (PageHighMem(page
))
1337 list_del(&page
->lru
);
1338 update_and_free_page(h
, page
);
1339 h
->free_huge_pages
--;
1340 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1345 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1346 nodemask_t
*nodes_allowed
)
1352 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1353 * balanced by operating on them in a round-robin fashion.
1354 * Returns 1 if an adjustment was made.
1356 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1361 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1364 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1365 if (h
->surplus_huge_pages_node
[node
])
1369 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1370 if (h
->surplus_huge_pages_node
[node
] <
1371 h
->nr_huge_pages_node
[node
])
1378 h
->surplus_huge_pages
+= delta
;
1379 h
->surplus_huge_pages_node
[node
] += delta
;
1383 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1384 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1385 nodemask_t
*nodes_allowed
)
1387 unsigned long min_count
, ret
;
1389 if (h
->order
>= MAX_ORDER
)
1390 return h
->max_huge_pages
;
1393 * Increase the pool size
1394 * First take pages out of surplus state. Then make up the
1395 * remaining difference by allocating fresh huge pages.
1397 * We might race with alloc_buddy_huge_page() here and be unable
1398 * to convert a surplus huge page to a normal huge page. That is
1399 * not critical, though, it just means the overall size of the
1400 * pool might be one hugepage larger than it needs to be, but
1401 * within all the constraints specified by the sysctls.
1403 spin_lock(&hugetlb_lock
);
1404 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1405 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1409 while (count
> persistent_huge_pages(h
)) {
1411 * If this allocation races such that we no longer need the
1412 * page, free_huge_page will handle it by freeing the page
1413 * and reducing the surplus.
1415 spin_unlock(&hugetlb_lock
);
1416 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1417 spin_lock(&hugetlb_lock
);
1421 /* Bail for signals. Probably ctrl-c from user */
1422 if (signal_pending(current
))
1427 * Decrease the pool size
1428 * First return free pages to the buddy allocator (being careful
1429 * to keep enough around to satisfy reservations). Then place
1430 * pages into surplus state as needed so the pool will shrink
1431 * to the desired size as pages become free.
1433 * By placing pages into the surplus state independent of the
1434 * overcommit value, we are allowing the surplus pool size to
1435 * exceed overcommit. There are few sane options here. Since
1436 * alloc_buddy_huge_page() is checking the global counter,
1437 * though, we'll note that we're not allowed to exceed surplus
1438 * and won't grow the pool anywhere else. Not until one of the
1439 * sysctls are changed, or the surplus pages go out of use.
1441 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1442 min_count
= max(count
, min_count
);
1443 try_to_free_low(h
, min_count
, nodes_allowed
);
1444 while (min_count
< persistent_huge_pages(h
)) {
1445 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1448 while (count
< persistent_huge_pages(h
)) {
1449 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1453 ret
= persistent_huge_pages(h
);
1454 spin_unlock(&hugetlb_lock
);
1458 #define HSTATE_ATTR_RO(_name) \
1459 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1461 #define HSTATE_ATTR(_name) \
1462 static struct kobj_attribute _name##_attr = \
1463 __ATTR(_name, 0644, _name##_show, _name##_store)
1465 static struct kobject
*hugepages_kobj
;
1466 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1468 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1470 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1474 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1475 if (hstate_kobjs
[i
] == kobj
) {
1477 *nidp
= NUMA_NO_NODE
;
1481 return kobj_to_node_hstate(kobj
, nidp
);
1484 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1485 struct kobj_attribute
*attr
, char *buf
)
1488 unsigned long nr_huge_pages
;
1491 h
= kobj_to_hstate(kobj
, &nid
);
1492 if (nid
== NUMA_NO_NODE
)
1493 nr_huge_pages
= h
->nr_huge_pages
;
1495 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1497 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1500 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1501 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1502 const char *buf
, size_t len
)
1506 unsigned long count
;
1508 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1510 err
= kstrtoul(buf
, 10, &count
);
1514 h
= kobj_to_hstate(kobj
, &nid
);
1515 if (h
->order
>= MAX_ORDER
) {
1520 if (nid
== NUMA_NO_NODE
) {
1522 * global hstate attribute
1524 if (!(obey_mempolicy
&&
1525 init_nodemask_of_mempolicy(nodes_allowed
))) {
1526 NODEMASK_FREE(nodes_allowed
);
1527 nodes_allowed
= &node_states
[N_MEMORY
];
1529 } else if (nodes_allowed
) {
1531 * per node hstate attribute: adjust count to global,
1532 * but restrict alloc/free to the specified node.
1534 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1535 init_nodemask_of_node(nodes_allowed
, nid
);
1537 nodes_allowed
= &node_states
[N_MEMORY
];
1539 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1541 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1542 NODEMASK_FREE(nodes_allowed
);
1546 NODEMASK_FREE(nodes_allowed
);
1550 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1551 struct kobj_attribute
*attr
, char *buf
)
1553 return nr_hugepages_show_common(kobj
, attr
, buf
);
1556 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1557 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1559 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1561 HSTATE_ATTR(nr_hugepages
);
1566 * hstate attribute for optionally mempolicy-based constraint on persistent
1567 * huge page alloc/free.
1569 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
1570 struct kobj_attribute
*attr
, char *buf
)
1572 return nr_hugepages_show_common(kobj
, attr
, buf
);
1575 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
1576 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1578 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1580 HSTATE_ATTR(nr_hugepages_mempolicy
);
1584 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1585 struct kobj_attribute
*attr
, char *buf
)
1587 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1588 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1591 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1592 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1595 unsigned long input
;
1596 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1598 if (h
->order
>= MAX_ORDER
)
1601 err
= kstrtoul(buf
, 10, &input
);
1605 spin_lock(&hugetlb_lock
);
1606 h
->nr_overcommit_huge_pages
= input
;
1607 spin_unlock(&hugetlb_lock
);
1611 HSTATE_ATTR(nr_overcommit_hugepages
);
1613 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1614 struct kobj_attribute
*attr
, char *buf
)
1617 unsigned long free_huge_pages
;
1620 h
= kobj_to_hstate(kobj
, &nid
);
1621 if (nid
== NUMA_NO_NODE
)
1622 free_huge_pages
= h
->free_huge_pages
;
1624 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1626 return sprintf(buf
, "%lu\n", free_huge_pages
);
1628 HSTATE_ATTR_RO(free_hugepages
);
1630 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1631 struct kobj_attribute
*attr
, char *buf
)
1633 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1634 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1636 HSTATE_ATTR_RO(resv_hugepages
);
1638 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1639 struct kobj_attribute
*attr
, char *buf
)
1642 unsigned long surplus_huge_pages
;
1645 h
= kobj_to_hstate(kobj
, &nid
);
1646 if (nid
== NUMA_NO_NODE
)
1647 surplus_huge_pages
= h
->surplus_huge_pages
;
1649 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1651 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1653 HSTATE_ATTR_RO(surplus_hugepages
);
1655 static struct attribute
*hstate_attrs
[] = {
1656 &nr_hugepages_attr
.attr
,
1657 &nr_overcommit_hugepages_attr
.attr
,
1658 &free_hugepages_attr
.attr
,
1659 &resv_hugepages_attr
.attr
,
1660 &surplus_hugepages_attr
.attr
,
1662 &nr_hugepages_mempolicy_attr
.attr
,
1667 static struct attribute_group hstate_attr_group
= {
1668 .attrs
= hstate_attrs
,
1671 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1672 struct kobject
**hstate_kobjs
,
1673 struct attribute_group
*hstate_attr_group
)
1676 int hi
= hstate_index(h
);
1678 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1679 if (!hstate_kobjs
[hi
])
1682 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1684 kobject_put(hstate_kobjs
[hi
]);
1689 static void __init
hugetlb_sysfs_init(void)
1694 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1695 if (!hugepages_kobj
)
1698 for_each_hstate(h
) {
1699 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1700 hstate_kobjs
, &hstate_attr_group
);
1702 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1709 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1710 * with node devices in node_devices[] using a parallel array. The array
1711 * index of a node device or _hstate == node id.
1712 * This is here to avoid any static dependency of the node device driver, in
1713 * the base kernel, on the hugetlb module.
1715 struct node_hstate
{
1716 struct kobject
*hugepages_kobj
;
1717 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1719 struct node_hstate node_hstates
[MAX_NUMNODES
];
1722 * A subset of global hstate attributes for node devices
1724 static struct attribute
*per_node_hstate_attrs
[] = {
1725 &nr_hugepages_attr
.attr
,
1726 &free_hugepages_attr
.attr
,
1727 &surplus_hugepages_attr
.attr
,
1731 static struct attribute_group per_node_hstate_attr_group
= {
1732 .attrs
= per_node_hstate_attrs
,
1736 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1737 * Returns node id via non-NULL nidp.
1739 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1743 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1744 struct node_hstate
*nhs
= &node_hstates
[nid
];
1746 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1747 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1759 * Unregister hstate attributes from a single node device.
1760 * No-op if no hstate attributes attached.
1762 static void hugetlb_unregister_node(struct node
*node
)
1765 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1767 if (!nhs
->hugepages_kobj
)
1768 return; /* no hstate attributes */
1770 for_each_hstate(h
) {
1771 int idx
= hstate_index(h
);
1772 if (nhs
->hstate_kobjs
[idx
]) {
1773 kobject_put(nhs
->hstate_kobjs
[idx
]);
1774 nhs
->hstate_kobjs
[idx
] = NULL
;
1778 kobject_put(nhs
->hugepages_kobj
);
1779 nhs
->hugepages_kobj
= NULL
;
1783 * hugetlb module exit: unregister hstate attributes from node devices
1786 static void hugetlb_unregister_all_nodes(void)
1791 * disable node device registrations.
1793 register_hugetlbfs_with_node(NULL
, NULL
);
1796 * remove hstate attributes from any nodes that have them.
1798 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1799 hugetlb_unregister_node(node_devices
[nid
]);
1803 * Register hstate attributes for a single node device.
1804 * No-op if attributes already registered.
1806 static void hugetlb_register_node(struct node
*node
)
1809 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1812 if (nhs
->hugepages_kobj
)
1813 return; /* already allocated */
1815 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1817 if (!nhs
->hugepages_kobj
)
1820 for_each_hstate(h
) {
1821 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1823 &per_node_hstate_attr_group
);
1825 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1826 h
->name
, node
->dev
.id
);
1827 hugetlb_unregister_node(node
);
1834 * hugetlb init time: register hstate attributes for all registered node
1835 * devices of nodes that have memory. All on-line nodes should have
1836 * registered their associated device by this time.
1838 static void hugetlb_register_all_nodes(void)
1842 for_each_node_state(nid
, N_MEMORY
) {
1843 struct node
*node
= node_devices
[nid
];
1844 if (node
->dev
.id
== nid
)
1845 hugetlb_register_node(node
);
1849 * Let the node device driver know we're here so it can
1850 * [un]register hstate attributes on node hotplug.
1852 register_hugetlbfs_with_node(hugetlb_register_node
,
1853 hugetlb_unregister_node
);
1855 #else /* !CONFIG_NUMA */
1857 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1865 static void hugetlb_unregister_all_nodes(void) { }
1867 static void hugetlb_register_all_nodes(void) { }
1871 static void __exit
hugetlb_exit(void)
1875 hugetlb_unregister_all_nodes();
1877 for_each_hstate(h
) {
1878 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1881 kobject_put(hugepages_kobj
);
1883 module_exit(hugetlb_exit
);
1885 static int __init
hugetlb_init(void)
1887 /* Some platform decide whether they support huge pages at boot
1888 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1889 * there is no such support
1891 if (HPAGE_SHIFT
== 0)
1894 if (!size_to_hstate(default_hstate_size
)) {
1895 default_hstate_size
= HPAGE_SIZE
;
1896 if (!size_to_hstate(default_hstate_size
))
1897 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1899 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1900 if (default_hstate_max_huge_pages
)
1901 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1903 hugetlb_init_hstates();
1904 gather_bootmem_prealloc();
1907 hugetlb_sysfs_init();
1908 hugetlb_register_all_nodes();
1909 hugetlb_cgroup_file_init();
1913 module_init(hugetlb_init
);
1915 /* Should be called on processing a hugepagesz=... option */
1916 void __init
hugetlb_add_hstate(unsigned order
)
1921 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1922 pr_warning("hugepagesz= specified twice, ignoring\n");
1925 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1927 h
= &hstates
[hugetlb_max_hstate
++];
1929 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1930 h
->nr_huge_pages
= 0;
1931 h
->free_huge_pages
= 0;
1932 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1933 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1934 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1935 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
1936 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
1937 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1938 huge_page_size(h
)/1024);
1943 static int __init
hugetlb_nrpages_setup(char *s
)
1946 static unsigned long *last_mhp
;
1949 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1950 * so this hugepages= parameter goes to the "default hstate".
1952 if (!hugetlb_max_hstate
)
1953 mhp
= &default_hstate_max_huge_pages
;
1955 mhp
= &parsed_hstate
->max_huge_pages
;
1957 if (mhp
== last_mhp
) {
1958 pr_warning("hugepages= specified twice without "
1959 "interleaving hugepagesz=, ignoring\n");
1963 if (sscanf(s
, "%lu", mhp
) <= 0)
1967 * Global state is always initialized later in hugetlb_init.
1968 * But we need to allocate >= MAX_ORDER hstates here early to still
1969 * use the bootmem allocator.
1971 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1972 hugetlb_hstate_alloc_pages(parsed_hstate
);
1978 __setup("hugepages=", hugetlb_nrpages_setup
);
1980 static int __init
hugetlb_default_setup(char *s
)
1982 default_hstate_size
= memparse(s
, &s
);
1985 __setup("default_hugepagesz=", hugetlb_default_setup
);
1987 static unsigned int cpuset_mems_nr(unsigned int *array
)
1990 unsigned int nr
= 0;
1992 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1998 #ifdef CONFIG_SYSCTL
1999 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2000 struct ctl_table
*table
, int write
,
2001 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2003 struct hstate
*h
= &default_hstate
;
2007 tmp
= h
->max_huge_pages
;
2009 if (write
&& h
->order
>= MAX_ORDER
)
2013 table
->maxlen
= sizeof(unsigned long);
2014 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2019 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2020 GFP_KERNEL
| __GFP_NORETRY
);
2021 if (!(obey_mempolicy
&&
2022 init_nodemask_of_mempolicy(nodes_allowed
))) {
2023 NODEMASK_FREE(nodes_allowed
);
2024 nodes_allowed
= &node_states
[N_MEMORY
];
2026 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2028 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2029 NODEMASK_FREE(nodes_allowed
);
2035 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2036 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2039 return hugetlb_sysctl_handler_common(false, table
, write
,
2040 buffer
, length
, ppos
);
2044 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2045 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2047 return hugetlb_sysctl_handler_common(true, table
, write
,
2048 buffer
, length
, ppos
);
2050 #endif /* CONFIG_NUMA */
2052 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2053 void __user
*buffer
,
2054 size_t *length
, loff_t
*ppos
)
2056 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2057 if (hugepages_treat_as_movable
)
2058 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2060 htlb_alloc_mask
= GFP_HIGHUSER
;
2064 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2065 void __user
*buffer
,
2066 size_t *length
, loff_t
*ppos
)
2068 struct hstate
*h
= &default_hstate
;
2072 tmp
= h
->nr_overcommit_huge_pages
;
2074 if (write
&& h
->order
>= MAX_ORDER
)
2078 table
->maxlen
= sizeof(unsigned long);
2079 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2084 spin_lock(&hugetlb_lock
);
2085 h
->nr_overcommit_huge_pages
= tmp
;
2086 spin_unlock(&hugetlb_lock
);
2092 #endif /* CONFIG_SYSCTL */
2094 void hugetlb_report_meminfo(struct seq_file
*m
)
2096 struct hstate
*h
= &default_hstate
;
2098 "HugePages_Total: %5lu\n"
2099 "HugePages_Free: %5lu\n"
2100 "HugePages_Rsvd: %5lu\n"
2101 "HugePages_Surp: %5lu\n"
2102 "Hugepagesize: %8lu kB\n",
2106 h
->surplus_huge_pages
,
2107 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2110 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2112 struct hstate
*h
= &default_hstate
;
2114 "Node %d HugePages_Total: %5u\n"
2115 "Node %d HugePages_Free: %5u\n"
2116 "Node %d HugePages_Surp: %5u\n",
2117 nid
, h
->nr_huge_pages_node
[nid
],
2118 nid
, h
->free_huge_pages_node
[nid
],
2119 nid
, h
->surplus_huge_pages_node
[nid
]);
2122 void hugetlb_show_meminfo(void)
2127 for_each_node_state(nid
, N_MEMORY
)
2129 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2131 h
->nr_huge_pages_node
[nid
],
2132 h
->free_huge_pages_node
[nid
],
2133 h
->surplus_huge_pages_node
[nid
],
2134 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2137 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2138 unsigned long hugetlb_total_pages(void)
2141 unsigned long nr_total_pages
= 0;
2144 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2145 return nr_total_pages
;
2148 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2152 spin_lock(&hugetlb_lock
);
2154 * When cpuset is configured, it breaks the strict hugetlb page
2155 * reservation as the accounting is done on a global variable. Such
2156 * reservation is completely rubbish in the presence of cpuset because
2157 * the reservation is not checked against page availability for the
2158 * current cpuset. Application can still potentially OOM'ed by kernel
2159 * with lack of free htlb page in cpuset that the task is in.
2160 * Attempt to enforce strict accounting with cpuset is almost
2161 * impossible (or too ugly) because cpuset is too fluid that
2162 * task or memory node can be dynamically moved between cpusets.
2164 * The change of semantics for shared hugetlb mapping with cpuset is
2165 * undesirable. However, in order to preserve some of the semantics,
2166 * we fall back to check against current free page availability as
2167 * a best attempt and hopefully to minimize the impact of changing
2168 * semantics that cpuset has.
2171 if (gather_surplus_pages(h
, delta
) < 0)
2174 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2175 return_unused_surplus_pages(h
, delta
);
2182 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2185 spin_unlock(&hugetlb_lock
);
2189 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2191 struct resv_map
*resv
= vma_resv_map(vma
);
2194 * This new VMA should share its siblings reservation map if present.
2195 * The VMA will only ever have a valid reservation map pointer where
2196 * it is being copied for another still existing VMA. As that VMA
2197 * has a reference to the reservation map it cannot disappear until
2198 * after this open call completes. It is therefore safe to take a
2199 * new reference here without additional locking.
2202 kref_get(&resv
->refs
);
2205 static void resv_map_put(struct vm_area_struct
*vma
)
2207 struct resv_map
*resv
= vma_resv_map(vma
);
2211 kref_put(&resv
->refs
, resv_map_release
);
2214 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2216 struct hstate
*h
= hstate_vma(vma
);
2217 struct resv_map
*resv
= vma_resv_map(vma
);
2218 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2219 unsigned long reserve
;
2220 unsigned long start
;
2224 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2225 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2227 reserve
= (end
- start
) -
2228 region_count(&resv
->regions
, start
, end
);
2233 hugetlb_acct_memory(h
, -reserve
);
2234 hugepage_subpool_put_pages(spool
, reserve
);
2240 * We cannot handle pagefaults against hugetlb pages at all. They cause
2241 * handle_mm_fault() to try to instantiate regular-sized pages in the
2242 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2245 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2251 const struct vm_operations_struct hugetlb_vm_ops
= {
2252 .fault
= hugetlb_vm_op_fault
,
2253 .open
= hugetlb_vm_op_open
,
2254 .close
= hugetlb_vm_op_close
,
2257 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2263 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2264 vma
->vm_page_prot
)));
2266 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2267 vma
->vm_page_prot
));
2269 entry
= pte_mkyoung(entry
);
2270 entry
= pte_mkhuge(entry
);
2271 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2276 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2277 unsigned long address
, pte_t
*ptep
)
2281 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2282 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2283 update_mmu_cache(vma
, address
, ptep
);
2287 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2288 struct vm_area_struct
*vma
)
2290 pte_t
*src_pte
, *dst_pte
, entry
;
2291 struct page
*ptepage
;
2294 struct hstate
*h
= hstate_vma(vma
);
2295 unsigned long sz
= huge_page_size(h
);
2297 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2299 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2300 src_pte
= huge_pte_offset(src
, addr
);
2303 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2307 /* If the pagetables are shared don't copy or take references */
2308 if (dst_pte
== src_pte
)
2311 spin_lock(&dst
->page_table_lock
);
2312 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2313 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2315 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2316 entry
= huge_ptep_get(src_pte
);
2317 ptepage
= pte_page(entry
);
2319 page_dup_rmap(ptepage
);
2320 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2322 spin_unlock(&src
->page_table_lock
);
2323 spin_unlock(&dst
->page_table_lock
);
2331 static int is_hugetlb_entry_migration(pte_t pte
)
2335 if (huge_pte_none(pte
) || pte_present(pte
))
2337 swp
= pte_to_swp_entry(pte
);
2338 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2344 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2348 if (huge_pte_none(pte
) || pte_present(pte
))
2350 swp
= pte_to_swp_entry(pte
);
2351 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2357 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2358 unsigned long start
, unsigned long end
,
2359 struct page
*ref_page
)
2361 int force_flush
= 0;
2362 struct mm_struct
*mm
= vma
->vm_mm
;
2363 unsigned long address
;
2367 struct hstate
*h
= hstate_vma(vma
);
2368 unsigned long sz
= huge_page_size(h
);
2369 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2370 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2372 WARN_ON(!is_vm_hugetlb_page(vma
));
2373 BUG_ON(start
& ~huge_page_mask(h
));
2374 BUG_ON(end
& ~huge_page_mask(h
));
2376 tlb_start_vma(tlb
, vma
);
2377 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2379 spin_lock(&mm
->page_table_lock
);
2380 for (address
= start
; address
< end
; address
+= sz
) {
2381 ptep
= huge_pte_offset(mm
, address
);
2385 if (huge_pmd_unshare(mm
, &address
, ptep
))
2388 pte
= huge_ptep_get(ptep
);
2389 if (huge_pte_none(pte
))
2393 * HWPoisoned hugepage is already unmapped and dropped reference
2395 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2396 huge_pte_clear(mm
, address
, ptep
);
2400 page
= pte_page(pte
);
2402 * If a reference page is supplied, it is because a specific
2403 * page is being unmapped, not a range. Ensure the page we
2404 * are about to unmap is the actual page of interest.
2407 if (page
!= ref_page
)
2411 * Mark the VMA as having unmapped its page so that
2412 * future faults in this VMA will fail rather than
2413 * looking like data was lost
2415 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2418 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2419 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2420 if (huge_pte_dirty(pte
))
2421 set_page_dirty(page
);
2423 page_remove_rmap(page
);
2424 force_flush
= !__tlb_remove_page(tlb
, page
);
2427 /* Bail out after unmapping reference page if supplied */
2431 spin_unlock(&mm
->page_table_lock
);
2433 * mmu_gather ran out of room to batch pages, we break out of
2434 * the PTE lock to avoid doing the potential expensive TLB invalidate
2435 * and page-free while holding it.
2440 if (address
< end
&& !ref_page
)
2443 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2444 tlb_end_vma(tlb
, vma
);
2447 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2448 struct vm_area_struct
*vma
, unsigned long start
,
2449 unsigned long end
, struct page
*ref_page
)
2451 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2454 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2455 * test will fail on a vma being torn down, and not grab a page table
2456 * on its way out. We're lucky that the flag has such an appropriate
2457 * name, and can in fact be safely cleared here. We could clear it
2458 * before the __unmap_hugepage_range above, but all that's necessary
2459 * is to clear it before releasing the i_mmap_mutex. This works
2460 * because in the context this is called, the VMA is about to be
2461 * destroyed and the i_mmap_mutex is held.
2463 vma
->vm_flags
&= ~VM_MAYSHARE
;
2466 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2467 unsigned long end
, struct page
*ref_page
)
2469 struct mm_struct
*mm
;
2470 struct mmu_gather tlb
;
2474 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2475 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2476 tlb_finish_mmu(&tlb
, start
, end
);
2480 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2481 * mappping it owns the reserve page for. The intention is to unmap the page
2482 * from other VMAs and let the children be SIGKILLed if they are faulting the
2485 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2486 struct page
*page
, unsigned long address
)
2488 struct hstate
*h
= hstate_vma(vma
);
2489 struct vm_area_struct
*iter_vma
;
2490 struct address_space
*mapping
;
2494 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2495 * from page cache lookup which is in HPAGE_SIZE units.
2497 address
= address
& huge_page_mask(h
);
2498 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2500 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2503 * Take the mapping lock for the duration of the table walk. As
2504 * this mapping should be shared between all the VMAs,
2505 * __unmap_hugepage_range() is called as the lock is already held
2507 mutex_lock(&mapping
->i_mmap_mutex
);
2508 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2509 /* Do not unmap the current VMA */
2510 if (iter_vma
== vma
)
2514 * Unmap the page from other VMAs without their own reserves.
2515 * They get marked to be SIGKILLed if they fault in these
2516 * areas. This is because a future no-page fault on this VMA
2517 * could insert a zeroed page instead of the data existing
2518 * from the time of fork. This would look like data corruption
2520 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2521 unmap_hugepage_range(iter_vma
, address
,
2522 address
+ huge_page_size(h
), page
);
2524 mutex_unlock(&mapping
->i_mmap_mutex
);
2530 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2531 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2532 * cannot race with other handlers or page migration.
2533 * Keep the pte_same checks anyway to make transition from the mutex easier.
2535 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2536 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2537 struct page
*pagecache_page
)
2539 struct hstate
*h
= hstate_vma(vma
);
2540 struct page
*old_page
, *new_page
;
2541 int outside_reserve
= 0;
2542 unsigned long mmun_start
; /* For mmu_notifiers */
2543 unsigned long mmun_end
; /* For mmu_notifiers */
2545 old_page
= pte_page(pte
);
2548 /* If no-one else is actually using this page, avoid the copy
2549 * and just make the page writable */
2550 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2551 page_move_anon_rmap(old_page
, vma
, address
);
2552 set_huge_ptep_writable(vma
, address
, ptep
);
2557 * If the process that created a MAP_PRIVATE mapping is about to
2558 * perform a COW due to a shared page count, attempt to satisfy
2559 * the allocation without using the existing reserves. The pagecache
2560 * page is used to determine if the reserve at this address was
2561 * consumed or not. If reserves were used, a partial faulted mapping
2562 * at the time of fork() could consume its reserves on COW instead
2563 * of the full address range.
2565 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2566 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2567 old_page
!= pagecache_page
)
2568 outside_reserve
= 1;
2570 page_cache_get(old_page
);
2572 /* Drop page_table_lock as buddy allocator may be called */
2573 spin_unlock(&mm
->page_table_lock
);
2574 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2576 if (IS_ERR(new_page
)) {
2577 long err
= PTR_ERR(new_page
);
2578 page_cache_release(old_page
);
2581 * If a process owning a MAP_PRIVATE mapping fails to COW,
2582 * it is due to references held by a child and an insufficient
2583 * huge page pool. To guarantee the original mappers
2584 * reliability, unmap the page from child processes. The child
2585 * may get SIGKILLed if it later faults.
2587 if (outside_reserve
) {
2588 BUG_ON(huge_pte_none(pte
));
2589 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2590 BUG_ON(huge_pte_none(pte
));
2591 spin_lock(&mm
->page_table_lock
);
2592 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2593 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2594 goto retry_avoidcopy
;
2596 * race occurs while re-acquiring page_table_lock, and
2604 /* Caller expects lock to be held */
2605 spin_lock(&mm
->page_table_lock
);
2607 return VM_FAULT_OOM
;
2609 return VM_FAULT_SIGBUS
;
2613 * When the original hugepage is shared one, it does not have
2614 * anon_vma prepared.
2616 if (unlikely(anon_vma_prepare(vma
))) {
2617 page_cache_release(new_page
);
2618 page_cache_release(old_page
);
2619 /* Caller expects lock to be held */
2620 spin_lock(&mm
->page_table_lock
);
2621 return VM_FAULT_OOM
;
2624 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2625 pages_per_huge_page(h
));
2626 __SetPageUptodate(new_page
);
2628 mmun_start
= address
& huge_page_mask(h
);
2629 mmun_end
= mmun_start
+ huge_page_size(h
);
2630 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2632 * Retake the page_table_lock to check for racing updates
2633 * before the page tables are altered
2635 spin_lock(&mm
->page_table_lock
);
2636 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2637 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2639 huge_ptep_clear_flush(vma
, address
, ptep
);
2640 set_huge_pte_at(mm
, address
, ptep
,
2641 make_huge_pte(vma
, new_page
, 1));
2642 page_remove_rmap(old_page
);
2643 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2644 /* Make the old page be freed below */
2645 new_page
= old_page
;
2647 spin_unlock(&mm
->page_table_lock
);
2648 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2649 /* Caller expects lock to be held */
2650 spin_lock(&mm
->page_table_lock
);
2651 page_cache_release(new_page
);
2652 page_cache_release(old_page
);
2656 /* Return the pagecache page at a given address within a VMA */
2657 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2658 struct vm_area_struct
*vma
, unsigned long address
)
2660 struct address_space
*mapping
;
2663 mapping
= vma
->vm_file
->f_mapping
;
2664 idx
= vma_hugecache_offset(h
, vma
, address
);
2666 return find_lock_page(mapping
, idx
);
2670 * Return whether there is a pagecache page to back given address within VMA.
2671 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2673 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2674 struct vm_area_struct
*vma
, unsigned long address
)
2676 struct address_space
*mapping
;
2680 mapping
= vma
->vm_file
->f_mapping
;
2681 idx
= vma_hugecache_offset(h
, vma
, address
);
2683 page
= find_get_page(mapping
, idx
);
2686 return page
!= NULL
;
2689 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2690 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2692 struct hstate
*h
= hstate_vma(vma
);
2693 int ret
= VM_FAULT_SIGBUS
;
2698 struct address_space
*mapping
;
2702 * Currently, we are forced to kill the process in the event the
2703 * original mapper has unmapped pages from the child due to a failed
2704 * COW. Warn that such a situation has occurred as it may not be obvious
2706 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2707 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2712 mapping
= vma
->vm_file
->f_mapping
;
2713 idx
= vma_hugecache_offset(h
, vma
, address
);
2716 * Use page lock to guard against racing truncation
2717 * before we get page_table_lock.
2720 page
= find_lock_page(mapping
, idx
);
2722 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2725 page
= alloc_huge_page(vma
, address
, 0);
2727 ret
= PTR_ERR(page
);
2731 ret
= VM_FAULT_SIGBUS
;
2734 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2735 __SetPageUptodate(page
);
2737 if (vma
->vm_flags
& VM_MAYSHARE
) {
2739 struct inode
*inode
= mapping
->host
;
2741 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2749 spin_lock(&inode
->i_lock
);
2750 inode
->i_blocks
+= blocks_per_huge_page(h
);
2751 spin_unlock(&inode
->i_lock
);
2754 if (unlikely(anon_vma_prepare(vma
))) {
2756 goto backout_unlocked
;
2762 * If memory error occurs between mmap() and fault, some process
2763 * don't have hwpoisoned swap entry for errored virtual address.
2764 * So we need to block hugepage fault by PG_hwpoison bit check.
2766 if (unlikely(PageHWPoison(page
))) {
2767 ret
= VM_FAULT_HWPOISON
|
2768 VM_FAULT_SET_HINDEX(hstate_index(h
));
2769 goto backout_unlocked
;
2774 * If we are going to COW a private mapping later, we examine the
2775 * pending reservations for this page now. This will ensure that
2776 * any allocations necessary to record that reservation occur outside
2779 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2780 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2782 goto backout_unlocked
;
2785 spin_lock(&mm
->page_table_lock
);
2786 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2791 if (!huge_pte_none(huge_ptep_get(ptep
)))
2795 hugepage_add_new_anon_rmap(page
, vma
, address
);
2797 page_dup_rmap(page
);
2798 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2799 && (vma
->vm_flags
& VM_SHARED
)));
2800 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2802 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2803 /* Optimization, do the COW without a second fault */
2804 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2807 spin_unlock(&mm
->page_table_lock
);
2813 spin_unlock(&mm
->page_table_lock
);
2820 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2821 unsigned long address
, unsigned int flags
)
2826 struct page
*page
= NULL
;
2827 struct page
*pagecache_page
= NULL
;
2828 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2829 struct hstate
*h
= hstate_vma(vma
);
2831 address
&= huge_page_mask(h
);
2833 ptep
= huge_pte_offset(mm
, address
);
2835 entry
= huge_ptep_get(ptep
);
2836 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2837 migration_entry_wait_huge(mm
, ptep
);
2839 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2840 return VM_FAULT_HWPOISON_LARGE
|
2841 VM_FAULT_SET_HINDEX(hstate_index(h
));
2844 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2846 return VM_FAULT_OOM
;
2849 * Serialize hugepage allocation and instantiation, so that we don't
2850 * get spurious allocation failures if two CPUs race to instantiate
2851 * the same page in the page cache.
2853 mutex_lock(&hugetlb_instantiation_mutex
);
2854 entry
= huge_ptep_get(ptep
);
2855 if (huge_pte_none(entry
)) {
2856 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2863 * If we are going to COW the mapping later, we examine the pending
2864 * reservations for this page now. This will ensure that any
2865 * allocations necessary to record that reservation occur outside the
2866 * spinlock. For private mappings, we also lookup the pagecache
2867 * page now as it is used to determine if a reservation has been
2870 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
2871 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2876 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2877 pagecache_page
= hugetlbfs_pagecache_page(h
,
2882 * hugetlb_cow() requires page locks of pte_page(entry) and
2883 * pagecache_page, so here we need take the former one
2884 * when page != pagecache_page or !pagecache_page.
2885 * Note that locking order is always pagecache_page -> page,
2886 * so no worry about deadlock.
2888 page
= pte_page(entry
);
2890 if (page
!= pagecache_page
)
2893 spin_lock(&mm
->page_table_lock
);
2894 /* Check for a racing update before calling hugetlb_cow */
2895 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2896 goto out_page_table_lock
;
2899 if (flags
& FAULT_FLAG_WRITE
) {
2900 if (!huge_pte_write(entry
)) {
2901 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2903 goto out_page_table_lock
;
2905 entry
= huge_pte_mkdirty(entry
);
2907 entry
= pte_mkyoung(entry
);
2908 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2909 flags
& FAULT_FLAG_WRITE
))
2910 update_mmu_cache(vma
, address
, ptep
);
2912 out_page_table_lock
:
2913 spin_unlock(&mm
->page_table_lock
);
2915 if (pagecache_page
) {
2916 unlock_page(pagecache_page
);
2917 put_page(pagecache_page
);
2919 if (page
!= pagecache_page
)
2924 mutex_unlock(&hugetlb_instantiation_mutex
);
2929 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2930 struct page
**pages
, struct vm_area_struct
**vmas
,
2931 unsigned long *position
, unsigned long *nr_pages
,
2932 long i
, unsigned int flags
)
2934 unsigned long pfn_offset
;
2935 unsigned long vaddr
= *position
;
2936 unsigned long remainder
= *nr_pages
;
2937 struct hstate
*h
= hstate_vma(vma
);
2939 spin_lock(&mm
->page_table_lock
);
2940 while (vaddr
< vma
->vm_end
&& remainder
) {
2946 * Some archs (sparc64, sh*) have multiple pte_ts to
2947 * each hugepage. We have to make sure we get the
2948 * first, for the page indexing below to work.
2950 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2951 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2954 * When coredumping, it suits get_dump_page if we just return
2955 * an error where there's an empty slot with no huge pagecache
2956 * to back it. This way, we avoid allocating a hugepage, and
2957 * the sparse dumpfile avoids allocating disk blocks, but its
2958 * huge holes still show up with zeroes where they need to be.
2960 if (absent
&& (flags
& FOLL_DUMP
) &&
2961 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2967 * We need call hugetlb_fault for both hugepages under migration
2968 * (in which case hugetlb_fault waits for the migration,) and
2969 * hwpoisoned hugepages (in which case we need to prevent the
2970 * caller from accessing to them.) In order to do this, we use
2971 * here is_swap_pte instead of is_hugetlb_entry_migration and
2972 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
2973 * both cases, and because we can't follow correct pages
2974 * directly from any kind of swap entries.
2976 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
2977 ((flags
& FOLL_WRITE
) &&
2978 !huge_pte_write(huge_ptep_get(pte
)))) {
2981 spin_unlock(&mm
->page_table_lock
);
2982 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2983 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2984 spin_lock(&mm
->page_table_lock
);
2985 if (!(ret
& VM_FAULT_ERROR
))
2992 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2993 page
= pte_page(huge_ptep_get(pte
));
2996 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3007 if (vaddr
< vma
->vm_end
&& remainder
&&
3008 pfn_offset
< pages_per_huge_page(h
)) {
3010 * We use pfn_offset to avoid touching the pageframes
3011 * of this compound page.
3016 spin_unlock(&mm
->page_table_lock
);
3017 *nr_pages
= remainder
;
3020 return i
? i
: -EFAULT
;
3023 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3024 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3026 struct mm_struct
*mm
= vma
->vm_mm
;
3027 unsigned long start
= address
;
3030 struct hstate
*h
= hstate_vma(vma
);
3031 unsigned long pages
= 0;
3033 BUG_ON(address
>= end
);
3034 flush_cache_range(vma
, address
, end
);
3036 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3037 spin_lock(&mm
->page_table_lock
);
3038 for (; address
< end
; address
+= huge_page_size(h
)) {
3039 ptep
= huge_pte_offset(mm
, address
);
3042 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3046 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3047 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3048 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3049 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3050 set_huge_pte_at(mm
, address
, ptep
, pte
);
3054 spin_unlock(&mm
->page_table_lock
);
3056 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3057 * may have cleared our pud entry and done put_page on the page table:
3058 * once we release i_mmap_mutex, another task can do the final put_page
3059 * and that page table be reused and filled with junk.
3061 flush_tlb_range(vma
, start
, end
);
3062 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3064 return pages
<< h
->order
;
3067 int hugetlb_reserve_pages(struct inode
*inode
,
3069 struct vm_area_struct
*vma
,
3070 vm_flags_t vm_flags
)
3073 struct hstate
*h
= hstate_inode(inode
);
3074 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3077 * Only apply hugepage reservation if asked. At fault time, an
3078 * attempt will be made for VM_NORESERVE to allocate a page
3079 * without using reserves
3081 if (vm_flags
& VM_NORESERVE
)
3085 * Shared mappings base their reservation on the number of pages that
3086 * are already allocated on behalf of the file. Private mappings need
3087 * to reserve the full area even if read-only as mprotect() may be
3088 * called to make the mapping read-write. Assume !vma is a shm mapping
3090 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3091 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3093 struct resv_map
*resv_map
= resv_map_alloc();
3099 set_vma_resv_map(vma
, resv_map
);
3100 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3108 /* There must be enough pages in the subpool for the mapping */
3109 if (hugepage_subpool_get_pages(spool
, chg
)) {
3115 * Check enough hugepages are available for the reservation.
3116 * Hand the pages back to the subpool if there are not
3118 ret
= hugetlb_acct_memory(h
, chg
);
3120 hugepage_subpool_put_pages(spool
, chg
);
3125 * Account for the reservations made. Shared mappings record regions
3126 * that have reservations as they are shared by multiple VMAs.
3127 * When the last VMA disappears, the region map says how much
3128 * the reservation was and the page cache tells how much of
3129 * the reservation was consumed. Private mappings are per-VMA and
3130 * only the consumed reservations are tracked. When the VMA
3131 * disappears, the original reservation is the VMA size and the
3132 * consumed reservations are stored in the map. Hence, nothing
3133 * else has to be done for private mappings here
3135 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3136 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3144 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3146 struct hstate
*h
= hstate_inode(inode
);
3147 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3148 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3150 spin_lock(&inode
->i_lock
);
3151 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3152 spin_unlock(&inode
->i_lock
);
3154 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3155 hugetlb_acct_memory(h
, -(chg
- freed
));
3158 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3159 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3160 struct vm_area_struct
*vma
,
3161 unsigned long addr
, pgoff_t idx
)
3163 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3165 unsigned long sbase
= saddr
& PUD_MASK
;
3166 unsigned long s_end
= sbase
+ PUD_SIZE
;
3168 /* Allow segments to share if only one is marked locked */
3169 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3170 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3173 * match the virtual addresses, permission and the alignment of the
3176 if (pmd_index(addr
) != pmd_index(saddr
) ||
3177 vm_flags
!= svm_flags
||
3178 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3184 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3186 unsigned long base
= addr
& PUD_MASK
;
3187 unsigned long end
= base
+ PUD_SIZE
;
3190 * check on proper vm_flags and page table alignment
3192 if (vma
->vm_flags
& VM_MAYSHARE
&&
3193 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3199 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3200 * and returns the corresponding pte. While this is not necessary for the
3201 * !shared pmd case because we can allocate the pmd later as well, it makes the
3202 * code much cleaner. pmd allocation is essential for the shared case because
3203 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3204 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3205 * bad pmd for sharing.
3207 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3209 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3210 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3211 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3213 struct vm_area_struct
*svma
;
3214 unsigned long saddr
;
3218 if (!vma_shareable(vma
, addr
))
3219 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3221 mutex_lock(&mapping
->i_mmap_mutex
);
3222 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3226 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3228 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3230 get_page(virt_to_page(spte
));
3239 spin_lock(&mm
->page_table_lock
);
3241 pud_populate(mm
, pud
,
3242 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3244 put_page(virt_to_page(spte
));
3245 spin_unlock(&mm
->page_table_lock
);
3247 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3248 mutex_unlock(&mapping
->i_mmap_mutex
);
3253 * unmap huge page backed by shared pte.
3255 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3256 * indicated by page_count > 1, unmap is achieved by clearing pud and
3257 * decrementing the ref count. If count == 1, the pte page is not shared.
3259 * called with vma->vm_mm->page_table_lock held.
3261 * returns: 1 successfully unmapped a shared pte page
3262 * 0 the underlying pte page is not shared, or it is the last user
3264 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3266 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3267 pud_t
*pud
= pud_offset(pgd
, *addr
);
3269 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3270 if (page_count(virt_to_page(ptep
)) == 1)
3274 put_page(virt_to_page(ptep
));
3275 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3278 #define want_pmd_share() (1)
3279 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3280 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3284 #define want_pmd_share() (0)
3285 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3287 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3288 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3289 unsigned long addr
, unsigned long sz
)
3295 pgd
= pgd_offset(mm
, addr
);
3296 pud
= pud_alloc(mm
, pgd
, addr
);
3298 if (sz
== PUD_SIZE
) {
3301 BUG_ON(sz
!= PMD_SIZE
);
3302 if (want_pmd_share() && pud_none(*pud
))
3303 pte
= huge_pmd_share(mm
, addr
, pud
);
3305 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3308 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3313 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3319 pgd
= pgd_offset(mm
, addr
);
3320 if (pgd_present(*pgd
)) {
3321 pud
= pud_offset(pgd
, addr
);
3322 if (pud_present(*pud
)) {
3324 return (pte_t
*)pud
;
3325 pmd
= pmd_offset(pud
, addr
);
3328 return (pte_t
*) pmd
;
3332 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3333 pmd_t
*pmd
, int write
)
3337 page
= pte_page(*(pte_t
*)pmd
);
3339 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3344 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3345 pud_t
*pud
, int write
)
3349 page
= pte_page(*(pte_t
*)pud
);
3351 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3355 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3357 /* Can be overriden by architectures */
3358 __attribute__((weak
)) struct page
*
3359 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3360 pud_t
*pud
, int write
)
3366 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3368 #ifdef CONFIG_MEMORY_FAILURE
3370 /* Should be called in hugetlb_lock */
3371 static int is_hugepage_on_freelist(struct page
*hpage
)
3375 struct hstate
*h
= page_hstate(hpage
);
3376 int nid
= page_to_nid(hpage
);
3378 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3385 * This function is called from memory failure code.
3386 * Assume the caller holds page lock of the head page.
3388 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3390 struct hstate
*h
= page_hstate(hpage
);
3391 int nid
= page_to_nid(hpage
);
3394 spin_lock(&hugetlb_lock
);
3395 if (is_hugepage_on_freelist(hpage
)) {
3397 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3398 * but dangling hpage->lru can trigger list-debug warnings
3399 * (this happens when we call unpoison_memory() on it),
3400 * so let it point to itself with list_del_init().
3402 list_del_init(&hpage
->lru
);
3403 set_page_refcounted(hpage
);
3404 h
->free_huge_pages
--;
3405 h
->free_huge_pages_node
[nid
]--;
3408 spin_unlock(&hugetlb_lock
);