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
)
448 if (vma
->vm_flags
& VM_NORESERVE
)
451 /* Shared mappings always use reserves */
452 if (vma
->vm_flags
& VM_MAYSHARE
)
456 * Only the process that called mmap() has reserves for
459 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
465 static void copy_gigantic_page(struct page
*dst
, struct page
*src
)
468 struct hstate
*h
= page_hstate(src
);
469 struct page
*dst_base
= dst
;
470 struct page
*src_base
= src
;
472 for (i
= 0; i
< pages_per_huge_page(h
); ) {
474 copy_highpage(dst
, src
);
477 dst
= mem_map_next(dst
, dst_base
, i
);
478 src
= mem_map_next(src
, src_base
, i
);
482 void copy_huge_page(struct page
*dst
, struct page
*src
)
485 struct hstate
*h
= page_hstate(src
);
487 if (unlikely(pages_per_huge_page(h
) > MAX_ORDER_NR_PAGES
)) {
488 copy_gigantic_page(dst
, src
);
493 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
495 copy_highpage(dst
+ i
, src
+ i
);
499 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
501 int nid
= page_to_nid(page
);
502 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
503 h
->free_huge_pages
++;
504 h
->free_huge_pages_node
[nid
]++;
507 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
511 if (list_empty(&h
->hugepage_freelists
[nid
]))
513 page
= list_entry(h
->hugepage_freelists
[nid
].next
, struct page
, lru
);
514 list_move(&page
->lru
, &h
->hugepage_activelist
);
515 set_page_refcounted(page
);
516 h
->free_huge_pages
--;
517 h
->free_huge_pages_node
[nid
]--;
521 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
522 struct vm_area_struct
*vma
,
523 unsigned long address
, int avoid_reserve
)
525 struct page
*page
= NULL
;
526 struct mempolicy
*mpol
;
527 nodemask_t
*nodemask
;
528 struct zonelist
*zonelist
;
531 unsigned int cpuset_mems_cookie
;
534 * A child process with MAP_PRIVATE mappings created by their parent
535 * have no page reserves. This check ensures that reservations are
536 * not "stolen". The child may still get SIGKILLed
538 if (!vma_has_reserves(vma
) &&
539 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
542 /* If reserves cannot be used, ensure enough pages are in the pool */
543 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
547 cpuset_mems_cookie
= get_mems_allowed();
548 zonelist
= huge_zonelist(vma
, address
,
549 htlb_alloc_mask
, &mpol
, &nodemask
);
551 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
552 MAX_NR_ZONES
- 1, nodemask
) {
553 if (cpuset_zone_allowed_softwall(zone
, htlb_alloc_mask
)) {
554 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
556 if (!avoid_reserve
&& vma_has_reserves(vma
))
557 h
->resv_huge_pages
--;
564 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !page
))
572 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
576 VM_BUG_ON(h
->order
>= MAX_ORDER
);
579 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
580 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
581 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
582 1 << PG_referenced
| 1 << PG_dirty
|
583 1 << PG_active
| 1 << PG_reserved
|
584 1 << PG_private
| 1 << PG_writeback
);
586 VM_BUG_ON(hugetlb_cgroup_from_page(page
));
587 set_compound_page_dtor(page
, NULL
);
588 set_page_refcounted(page
);
589 arch_release_hugepage(page
);
590 __free_pages(page
, huge_page_order(h
));
593 struct hstate
*size_to_hstate(unsigned long size
)
598 if (huge_page_size(h
) == size
)
604 static void free_huge_page(struct page
*page
)
607 * Can't pass hstate in here because it is called from the
608 * compound page destructor.
610 struct hstate
*h
= page_hstate(page
);
611 int nid
= page_to_nid(page
);
612 struct hugepage_subpool
*spool
=
613 (struct hugepage_subpool
*)page_private(page
);
615 set_page_private(page
, 0);
616 page
->mapping
= NULL
;
617 BUG_ON(page_count(page
));
618 BUG_ON(page_mapcount(page
));
620 spin_lock(&hugetlb_lock
);
621 hugetlb_cgroup_uncharge_page(hstate_index(h
),
622 pages_per_huge_page(h
), page
);
623 if (h
->surplus_huge_pages_node
[nid
] && huge_page_order(h
) < MAX_ORDER
) {
624 /* remove the page from active list */
625 list_del(&page
->lru
);
626 update_and_free_page(h
, page
);
627 h
->surplus_huge_pages
--;
628 h
->surplus_huge_pages_node
[nid
]--;
630 arch_clear_hugepage_flags(page
);
631 enqueue_huge_page(h
, page
);
633 spin_unlock(&hugetlb_lock
);
634 hugepage_subpool_put_pages(spool
, 1);
637 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
639 INIT_LIST_HEAD(&page
->lru
);
640 set_compound_page_dtor(page
, free_huge_page
);
641 spin_lock(&hugetlb_lock
);
642 set_hugetlb_cgroup(page
, NULL
);
644 h
->nr_huge_pages_node
[nid
]++;
645 spin_unlock(&hugetlb_lock
);
646 put_page(page
); /* free it into the hugepage allocator */
649 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
652 int nr_pages
= 1 << order
;
653 struct page
*p
= page
+ 1;
655 /* we rely on prep_new_huge_page to set the destructor */
656 set_compound_order(page
, order
);
658 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
660 set_page_count(p
, 0);
661 p
->first_page
= page
;
666 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
667 * transparent huge pages. See the PageTransHuge() documentation for more
670 int PageHuge(struct page
*page
)
672 compound_page_dtor
*dtor
;
674 if (!PageCompound(page
))
677 page
= compound_head(page
);
678 dtor
= get_compound_page_dtor(page
);
680 return dtor
== free_huge_page
;
682 EXPORT_SYMBOL_GPL(PageHuge
);
684 pgoff_t
__basepage_index(struct page
*page
)
686 struct page
*page_head
= compound_head(page
);
687 pgoff_t index
= page_index(page_head
);
688 unsigned long compound_idx
;
690 if (!PageHuge(page_head
))
691 return page_index(page
);
693 if (compound_order(page_head
) >= MAX_ORDER
)
694 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
696 compound_idx
= page
- page_head
;
698 return (index
<< compound_order(page_head
)) + compound_idx
;
701 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
705 if (h
->order
>= MAX_ORDER
)
708 page
= alloc_pages_exact_node(nid
,
709 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
710 __GFP_REPEAT
|__GFP_NOWARN
,
713 if (arch_prepare_hugepage(page
)) {
714 __free_pages(page
, huge_page_order(h
));
717 prep_new_huge_page(h
, page
, nid
);
724 * common helper functions for hstate_next_node_to_{alloc|free}.
725 * We may have allocated or freed a huge page based on a different
726 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
727 * be outside of *nodes_allowed. Ensure that we use an allowed
728 * node for alloc or free.
730 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
732 nid
= next_node(nid
, *nodes_allowed
);
733 if (nid
== MAX_NUMNODES
)
734 nid
= first_node(*nodes_allowed
);
735 VM_BUG_ON(nid
>= MAX_NUMNODES
);
740 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
742 if (!node_isset(nid
, *nodes_allowed
))
743 nid
= next_node_allowed(nid
, nodes_allowed
);
748 * returns the previously saved node ["this node"] from which to
749 * allocate a persistent huge page for the pool and advance the
750 * next node from which to allocate, handling wrap at end of node
753 static int hstate_next_node_to_alloc(struct hstate
*h
,
754 nodemask_t
*nodes_allowed
)
758 VM_BUG_ON(!nodes_allowed
);
760 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
761 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
767 * helper for free_pool_huge_page() - return the previously saved
768 * node ["this node"] from which to free a huge page. Advance the
769 * next node id whether or not we find a free huge page to free so
770 * that the next attempt to free addresses the next node.
772 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
776 VM_BUG_ON(!nodes_allowed
);
778 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
779 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
784 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
785 for (nr_nodes = nodes_weight(*mask); \
787 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
790 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
791 for (nr_nodes = nodes_weight(*mask); \
793 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
796 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
802 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
803 page
= alloc_fresh_huge_page_node(h
, node
);
811 count_vm_event(HTLB_BUDDY_PGALLOC
);
813 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
819 * Free huge page from pool from next node to free.
820 * Attempt to keep persistent huge pages more or less
821 * balanced over allowed nodes.
822 * Called with hugetlb_lock locked.
824 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
830 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
832 * If we're returning unused surplus pages, only examine
833 * nodes with surplus pages.
835 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
836 !list_empty(&h
->hugepage_freelists
[node
])) {
838 list_entry(h
->hugepage_freelists
[node
].next
,
840 list_del(&page
->lru
);
841 h
->free_huge_pages
--;
842 h
->free_huge_pages_node
[node
]--;
844 h
->surplus_huge_pages
--;
845 h
->surplus_huge_pages_node
[node
]--;
847 update_and_free_page(h
, page
);
856 static struct page
*alloc_buddy_huge_page(struct hstate
*h
, int nid
)
861 if (h
->order
>= MAX_ORDER
)
865 * Assume we will successfully allocate the surplus page to
866 * prevent racing processes from causing the surplus to exceed
869 * This however introduces a different race, where a process B
870 * tries to grow the static hugepage pool while alloc_pages() is
871 * called by process A. B will only examine the per-node
872 * counters in determining if surplus huge pages can be
873 * converted to normal huge pages in adjust_pool_surplus(). A
874 * won't be able to increment the per-node counter, until the
875 * lock is dropped by B, but B doesn't drop hugetlb_lock until
876 * no more huge pages can be converted from surplus to normal
877 * state (and doesn't try to convert again). Thus, we have a
878 * case where a surplus huge page exists, the pool is grown, and
879 * the surplus huge page still exists after, even though it
880 * should just have been converted to a normal huge page. This
881 * does not leak memory, though, as the hugepage will be freed
882 * once it is out of use. It also does not allow the counters to
883 * go out of whack in adjust_pool_surplus() as we don't modify
884 * the node values until we've gotten the hugepage and only the
885 * per-node value is checked there.
887 spin_lock(&hugetlb_lock
);
888 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
889 spin_unlock(&hugetlb_lock
);
893 h
->surplus_huge_pages
++;
895 spin_unlock(&hugetlb_lock
);
897 if (nid
== NUMA_NO_NODE
)
898 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|
899 __GFP_REPEAT
|__GFP_NOWARN
,
902 page
= alloc_pages_exact_node(nid
,
903 htlb_alloc_mask
|__GFP_COMP
|__GFP_THISNODE
|
904 __GFP_REPEAT
|__GFP_NOWARN
, huge_page_order(h
));
906 if (page
&& arch_prepare_hugepage(page
)) {
907 __free_pages(page
, huge_page_order(h
));
911 spin_lock(&hugetlb_lock
);
913 INIT_LIST_HEAD(&page
->lru
);
914 r_nid
= page_to_nid(page
);
915 set_compound_page_dtor(page
, free_huge_page
);
916 set_hugetlb_cgroup(page
, NULL
);
918 * We incremented the global counters already
920 h
->nr_huge_pages_node
[r_nid
]++;
921 h
->surplus_huge_pages_node
[r_nid
]++;
922 __count_vm_event(HTLB_BUDDY_PGALLOC
);
925 h
->surplus_huge_pages
--;
926 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
928 spin_unlock(&hugetlb_lock
);
934 * This allocation function is useful in the context where vma is irrelevant.
935 * E.g. soft-offlining uses this function because it only cares physical
936 * address of error page.
938 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
942 spin_lock(&hugetlb_lock
);
943 page
= dequeue_huge_page_node(h
, nid
);
944 spin_unlock(&hugetlb_lock
);
947 page
= alloc_buddy_huge_page(h
, nid
);
953 * Increase the hugetlb pool such that it can accommodate a reservation
956 static int gather_surplus_pages(struct hstate
*h
, int delta
)
958 struct list_head surplus_list
;
959 struct page
*page
, *tmp
;
961 int needed
, allocated
;
962 bool alloc_ok
= true;
964 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
966 h
->resv_huge_pages
+= delta
;
971 INIT_LIST_HEAD(&surplus_list
);
975 spin_unlock(&hugetlb_lock
);
976 for (i
= 0; i
< needed
; i
++) {
977 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
982 list_add(&page
->lru
, &surplus_list
);
987 * After retaking hugetlb_lock, we need to recalculate 'needed'
988 * because either resv_huge_pages or free_huge_pages may have changed.
990 spin_lock(&hugetlb_lock
);
991 needed
= (h
->resv_huge_pages
+ delta
) -
992 (h
->free_huge_pages
+ allocated
);
997 * We were not able to allocate enough pages to
998 * satisfy the entire reservation so we free what
999 * we've allocated so far.
1004 * The surplus_list now contains _at_least_ the number of extra pages
1005 * needed to accommodate the reservation. Add the appropriate number
1006 * of pages to the hugetlb pool and free the extras back to the buddy
1007 * allocator. Commit the entire reservation here to prevent another
1008 * process from stealing the pages as they are added to the pool but
1009 * before they are reserved.
1011 needed
+= allocated
;
1012 h
->resv_huge_pages
+= delta
;
1015 /* Free the needed pages to the hugetlb pool */
1016 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1020 * This page is now managed by the hugetlb allocator and has
1021 * no users -- drop the buddy allocator's reference.
1023 put_page_testzero(page
);
1024 VM_BUG_ON(page_count(page
));
1025 enqueue_huge_page(h
, page
);
1028 spin_unlock(&hugetlb_lock
);
1030 /* Free unnecessary surplus pages to the buddy allocator */
1031 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1033 spin_lock(&hugetlb_lock
);
1039 * When releasing a hugetlb pool reservation, any surplus pages that were
1040 * allocated to satisfy the reservation must be explicitly freed if they were
1042 * Called with hugetlb_lock held.
1044 static void return_unused_surplus_pages(struct hstate
*h
,
1045 unsigned long unused_resv_pages
)
1047 unsigned long nr_pages
;
1049 /* Uncommit the reservation */
1050 h
->resv_huge_pages
-= unused_resv_pages
;
1052 /* Cannot return gigantic pages currently */
1053 if (h
->order
>= MAX_ORDER
)
1056 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1059 * We want to release as many surplus pages as possible, spread
1060 * evenly across all nodes with memory. Iterate across these nodes
1061 * until we can no longer free unreserved surplus pages. This occurs
1062 * when the nodes with surplus pages have no free pages.
1063 * free_pool_huge_page() will balance the the freed pages across the
1064 * on-line nodes with memory and will handle the hstate accounting.
1066 while (nr_pages
--) {
1067 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1073 * Determine if the huge page at addr within the vma has an associated
1074 * reservation. Where it does not we will need to logically increase
1075 * reservation and actually increase subpool usage before an allocation
1076 * can occur. Where any new reservation would be required the
1077 * reservation change is prepared, but not committed. Once the page
1078 * has been allocated from the subpool and instantiated the change should
1079 * be committed via vma_commit_reservation. No action is required on
1082 static long vma_needs_reservation(struct hstate
*h
,
1083 struct vm_area_struct
*vma
, unsigned long addr
)
1085 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1086 struct inode
*inode
= mapping
->host
;
1088 if (vma
->vm_flags
& VM_MAYSHARE
) {
1089 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1090 return region_chg(&inode
->i_mapping
->private_list
,
1093 } else if (!is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1098 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1099 struct resv_map
*reservations
= vma_resv_map(vma
);
1101 err
= region_chg(&reservations
->regions
, idx
, idx
+ 1);
1107 static void vma_commit_reservation(struct hstate
*h
,
1108 struct vm_area_struct
*vma
, unsigned long addr
)
1110 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
1111 struct inode
*inode
= mapping
->host
;
1113 if (vma
->vm_flags
& VM_MAYSHARE
) {
1114 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1115 region_add(&inode
->i_mapping
->private_list
, idx
, idx
+ 1);
1117 } else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1118 pgoff_t idx
= vma_hugecache_offset(h
, vma
, addr
);
1119 struct resv_map
*reservations
= vma_resv_map(vma
);
1121 /* Mark this page used in the map. */
1122 region_add(&reservations
->regions
, idx
, idx
+ 1);
1126 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1127 unsigned long addr
, int avoid_reserve
)
1129 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1130 struct hstate
*h
= hstate_vma(vma
);
1134 struct hugetlb_cgroup
*h_cg
;
1136 idx
= hstate_index(h
);
1138 * Processes that did not create the mapping will have no
1139 * reserves and will not have accounted against subpool
1140 * limit. Check that the subpool limit can be made before
1141 * satisfying the allocation MAP_NORESERVE mappings may also
1142 * need pages and subpool limit allocated allocated if no reserve
1145 chg
= vma_needs_reservation(h
, vma
, addr
);
1147 return ERR_PTR(-ENOMEM
);
1149 if (hugepage_subpool_get_pages(spool
, chg
))
1150 return ERR_PTR(-ENOSPC
);
1152 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1154 hugepage_subpool_put_pages(spool
, chg
);
1155 return ERR_PTR(-ENOSPC
);
1157 spin_lock(&hugetlb_lock
);
1158 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
);
1160 spin_unlock(&hugetlb_lock
);
1161 page
= alloc_buddy_huge_page(h
, NUMA_NO_NODE
);
1163 hugetlb_cgroup_uncharge_cgroup(idx
,
1164 pages_per_huge_page(h
),
1166 hugepage_subpool_put_pages(spool
, chg
);
1167 return ERR_PTR(-ENOSPC
);
1169 spin_lock(&hugetlb_lock
);
1170 list_move(&page
->lru
, &h
->hugepage_activelist
);
1173 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1174 spin_unlock(&hugetlb_lock
);
1176 set_page_private(page
, (unsigned long)spool
);
1178 vma_commit_reservation(h
, vma
, addr
);
1182 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1184 struct huge_bootmem_page
*m
;
1187 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1190 addr
= __alloc_bootmem_node_nopanic(NODE_DATA(node
),
1191 huge_page_size(h
), huge_page_size(h
), 0);
1195 * Use the beginning of the huge page to store the
1196 * huge_bootmem_page struct (until gather_bootmem
1197 * puts them into the mem_map).
1206 BUG_ON((unsigned long)virt_to_phys(m
) & (huge_page_size(h
) - 1));
1207 /* Put them into a private list first because mem_map is not up yet */
1208 list_add(&m
->list
, &huge_boot_pages
);
1213 static void prep_compound_huge_page(struct page
*page
, int order
)
1215 if (unlikely(order
> (MAX_ORDER
- 1)))
1216 prep_compound_gigantic_page(page
, order
);
1218 prep_compound_page(page
, order
);
1221 /* Put bootmem huge pages into the standard lists after mem_map is up */
1222 static void __init
gather_bootmem_prealloc(void)
1224 struct huge_bootmem_page
*m
;
1226 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1227 struct hstate
*h
= m
->hstate
;
1230 #ifdef CONFIG_HIGHMEM
1231 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1232 free_bootmem_late((unsigned long)m
,
1233 sizeof(struct huge_bootmem_page
));
1235 page
= virt_to_page(m
);
1237 __ClearPageReserved(page
);
1238 WARN_ON(page_count(page
) != 1);
1239 prep_compound_huge_page(page
, h
->order
);
1240 prep_new_huge_page(h
, page
, page_to_nid(page
));
1242 * If we had gigantic hugepages allocated at boot time, we need
1243 * to restore the 'stolen' pages to totalram_pages in order to
1244 * fix confusing memory reports from free(1) and another
1245 * side-effects, like CommitLimit going negative.
1247 if (h
->order
> (MAX_ORDER
- 1))
1248 adjust_managed_page_count(page
, 1 << h
->order
);
1252 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
1256 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
1257 if (h
->order
>= MAX_ORDER
) {
1258 if (!alloc_bootmem_huge_page(h
))
1260 } else if (!alloc_fresh_huge_page(h
,
1261 &node_states
[N_MEMORY
]))
1264 h
->max_huge_pages
= i
;
1267 static void __init
hugetlb_init_hstates(void)
1271 for_each_hstate(h
) {
1272 /* oversize hugepages were init'ed in early boot */
1273 if (h
->order
< MAX_ORDER
)
1274 hugetlb_hstate_alloc_pages(h
);
1278 static char * __init
memfmt(char *buf
, unsigned long n
)
1280 if (n
>= (1UL << 30))
1281 sprintf(buf
, "%lu GB", n
>> 30);
1282 else if (n
>= (1UL << 20))
1283 sprintf(buf
, "%lu MB", n
>> 20);
1285 sprintf(buf
, "%lu KB", n
>> 10);
1289 static void __init
report_hugepages(void)
1293 for_each_hstate(h
) {
1295 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1296 memfmt(buf
, huge_page_size(h
)),
1297 h
->free_huge_pages
);
1301 #ifdef CONFIG_HIGHMEM
1302 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
1303 nodemask_t
*nodes_allowed
)
1307 if (h
->order
>= MAX_ORDER
)
1310 for_each_node_mask(i
, *nodes_allowed
) {
1311 struct page
*page
, *next
;
1312 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
1313 list_for_each_entry_safe(page
, next
, freel
, lru
) {
1314 if (count
>= h
->nr_huge_pages
)
1316 if (PageHighMem(page
))
1318 list_del(&page
->lru
);
1319 update_and_free_page(h
, page
);
1320 h
->free_huge_pages
--;
1321 h
->free_huge_pages_node
[page_to_nid(page
)]--;
1326 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
1327 nodemask_t
*nodes_allowed
)
1333 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1334 * balanced by operating on them in a round-robin fashion.
1335 * Returns 1 if an adjustment was made.
1337 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1342 VM_BUG_ON(delta
!= -1 && delta
!= 1);
1345 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1346 if (h
->surplus_huge_pages_node
[node
])
1350 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1351 if (h
->surplus_huge_pages_node
[node
] <
1352 h
->nr_huge_pages_node
[node
])
1359 h
->surplus_huge_pages
+= delta
;
1360 h
->surplus_huge_pages_node
[node
] += delta
;
1364 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1365 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
1366 nodemask_t
*nodes_allowed
)
1368 unsigned long min_count
, ret
;
1370 if (h
->order
>= MAX_ORDER
)
1371 return h
->max_huge_pages
;
1374 * Increase the pool size
1375 * First take pages out of surplus state. Then make up the
1376 * remaining difference by allocating fresh huge pages.
1378 * We might race with alloc_buddy_huge_page() here and be unable
1379 * to convert a surplus huge page to a normal huge page. That is
1380 * not critical, though, it just means the overall size of the
1381 * pool might be one hugepage larger than it needs to be, but
1382 * within all the constraints specified by the sysctls.
1384 spin_lock(&hugetlb_lock
);
1385 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
1386 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
1390 while (count
> persistent_huge_pages(h
)) {
1392 * If this allocation races such that we no longer need the
1393 * page, free_huge_page will handle it by freeing the page
1394 * and reducing the surplus.
1396 spin_unlock(&hugetlb_lock
);
1397 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
1398 spin_lock(&hugetlb_lock
);
1402 /* Bail for signals. Probably ctrl-c from user */
1403 if (signal_pending(current
))
1408 * Decrease the pool size
1409 * First return free pages to the buddy allocator (being careful
1410 * to keep enough around to satisfy reservations). Then place
1411 * pages into surplus state as needed so the pool will shrink
1412 * to the desired size as pages become free.
1414 * By placing pages into the surplus state independent of the
1415 * overcommit value, we are allowing the surplus pool size to
1416 * exceed overcommit. There are few sane options here. Since
1417 * alloc_buddy_huge_page() is checking the global counter,
1418 * though, we'll note that we're not allowed to exceed surplus
1419 * and won't grow the pool anywhere else. Not until one of the
1420 * sysctls are changed, or the surplus pages go out of use.
1422 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
1423 min_count
= max(count
, min_count
);
1424 try_to_free_low(h
, min_count
, nodes_allowed
);
1425 while (min_count
< persistent_huge_pages(h
)) {
1426 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
1429 while (count
< persistent_huge_pages(h
)) {
1430 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
1434 ret
= persistent_huge_pages(h
);
1435 spin_unlock(&hugetlb_lock
);
1439 #define HSTATE_ATTR_RO(_name) \
1440 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1442 #define HSTATE_ATTR(_name) \
1443 static struct kobj_attribute _name##_attr = \
1444 __ATTR(_name, 0644, _name##_show, _name##_store)
1446 static struct kobject
*hugepages_kobj
;
1447 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1449 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
1451 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
1455 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1456 if (hstate_kobjs
[i
] == kobj
) {
1458 *nidp
= NUMA_NO_NODE
;
1462 return kobj_to_node_hstate(kobj
, nidp
);
1465 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
1466 struct kobj_attribute
*attr
, char *buf
)
1469 unsigned long nr_huge_pages
;
1472 h
= kobj_to_hstate(kobj
, &nid
);
1473 if (nid
== NUMA_NO_NODE
)
1474 nr_huge_pages
= h
->nr_huge_pages
;
1476 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
1478 return sprintf(buf
, "%lu\n", nr_huge_pages
);
1481 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
1482 struct kobject
*kobj
, struct kobj_attribute
*attr
,
1483 const char *buf
, size_t len
)
1487 unsigned long count
;
1489 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
1491 err
= kstrtoul(buf
, 10, &count
);
1495 h
= kobj_to_hstate(kobj
, &nid
);
1496 if (h
->order
>= MAX_ORDER
) {
1501 if (nid
== NUMA_NO_NODE
) {
1503 * global hstate attribute
1505 if (!(obey_mempolicy
&&
1506 init_nodemask_of_mempolicy(nodes_allowed
))) {
1507 NODEMASK_FREE(nodes_allowed
);
1508 nodes_allowed
= &node_states
[N_MEMORY
];
1510 } else if (nodes_allowed
) {
1512 * per node hstate attribute: adjust count to global,
1513 * but restrict alloc/free to the specified node.
1515 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
1516 init_nodemask_of_node(nodes_allowed
, nid
);
1518 nodes_allowed
= &node_states
[N_MEMORY
];
1520 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
1522 if (nodes_allowed
!= &node_states
[N_MEMORY
])
1523 NODEMASK_FREE(nodes_allowed
);
1527 NODEMASK_FREE(nodes_allowed
);
1531 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
1532 struct kobj_attribute
*attr
, char *buf
)
1534 return nr_hugepages_show_common(kobj
, attr
, buf
);
1537 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
1538 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1540 return nr_hugepages_store_common(false, kobj
, attr
, buf
, len
);
1542 HSTATE_ATTR(nr_hugepages
);
1547 * hstate attribute for optionally mempolicy-based constraint on persistent
1548 * huge page alloc/free.
1550 static ssize_t
nr_hugepages_mempolicy_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_mempolicy_store(struct kobject
*kobj
,
1557 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
1559 return nr_hugepages_store_common(true, kobj
, attr
, buf
, len
);
1561 HSTATE_ATTR(nr_hugepages_mempolicy
);
1565 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
1566 struct kobj_attribute
*attr
, char *buf
)
1568 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1569 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
1572 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
1573 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
1576 unsigned long input
;
1577 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1579 if (h
->order
>= MAX_ORDER
)
1582 err
= kstrtoul(buf
, 10, &input
);
1586 spin_lock(&hugetlb_lock
);
1587 h
->nr_overcommit_huge_pages
= input
;
1588 spin_unlock(&hugetlb_lock
);
1592 HSTATE_ATTR(nr_overcommit_hugepages
);
1594 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
1595 struct kobj_attribute
*attr
, char *buf
)
1598 unsigned long free_huge_pages
;
1601 h
= kobj_to_hstate(kobj
, &nid
);
1602 if (nid
== NUMA_NO_NODE
)
1603 free_huge_pages
= h
->free_huge_pages
;
1605 free_huge_pages
= h
->free_huge_pages_node
[nid
];
1607 return sprintf(buf
, "%lu\n", free_huge_pages
);
1609 HSTATE_ATTR_RO(free_hugepages
);
1611 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
1612 struct kobj_attribute
*attr
, char *buf
)
1614 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
1615 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
1617 HSTATE_ATTR_RO(resv_hugepages
);
1619 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
1620 struct kobj_attribute
*attr
, char *buf
)
1623 unsigned long surplus_huge_pages
;
1626 h
= kobj_to_hstate(kobj
, &nid
);
1627 if (nid
== NUMA_NO_NODE
)
1628 surplus_huge_pages
= h
->surplus_huge_pages
;
1630 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
1632 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
1634 HSTATE_ATTR_RO(surplus_hugepages
);
1636 static struct attribute
*hstate_attrs
[] = {
1637 &nr_hugepages_attr
.attr
,
1638 &nr_overcommit_hugepages_attr
.attr
,
1639 &free_hugepages_attr
.attr
,
1640 &resv_hugepages_attr
.attr
,
1641 &surplus_hugepages_attr
.attr
,
1643 &nr_hugepages_mempolicy_attr
.attr
,
1648 static struct attribute_group hstate_attr_group
= {
1649 .attrs
= hstate_attrs
,
1652 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
1653 struct kobject
**hstate_kobjs
,
1654 struct attribute_group
*hstate_attr_group
)
1657 int hi
= hstate_index(h
);
1659 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
1660 if (!hstate_kobjs
[hi
])
1663 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
1665 kobject_put(hstate_kobjs
[hi
]);
1670 static void __init
hugetlb_sysfs_init(void)
1675 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
1676 if (!hugepages_kobj
)
1679 for_each_hstate(h
) {
1680 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
1681 hstate_kobjs
, &hstate_attr_group
);
1683 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
1690 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1691 * with node devices in node_devices[] using a parallel array. The array
1692 * index of a node device or _hstate == node id.
1693 * This is here to avoid any static dependency of the node device driver, in
1694 * the base kernel, on the hugetlb module.
1696 struct node_hstate
{
1697 struct kobject
*hugepages_kobj
;
1698 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
1700 struct node_hstate node_hstates
[MAX_NUMNODES
];
1703 * A subset of global hstate attributes for node devices
1705 static struct attribute
*per_node_hstate_attrs
[] = {
1706 &nr_hugepages_attr
.attr
,
1707 &free_hugepages_attr
.attr
,
1708 &surplus_hugepages_attr
.attr
,
1712 static struct attribute_group per_node_hstate_attr_group
= {
1713 .attrs
= per_node_hstate_attrs
,
1717 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1718 * Returns node id via non-NULL nidp.
1720 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1724 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
1725 struct node_hstate
*nhs
= &node_hstates
[nid
];
1727 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
1728 if (nhs
->hstate_kobjs
[i
] == kobj
) {
1740 * Unregister hstate attributes from a single node device.
1741 * No-op if no hstate attributes attached.
1743 static void hugetlb_unregister_node(struct node
*node
)
1746 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1748 if (!nhs
->hugepages_kobj
)
1749 return; /* no hstate attributes */
1751 for_each_hstate(h
) {
1752 int idx
= hstate_index(h
);
1753 if (nhs
->hstate_kobjs
[idx
]) {
1754 kobject_put(nhs
->hstate_kobjs
[idx
]);
1755 nhs
->hstate_kobjs
[idx
] = NULL
;
1759 kobject_put(nhs
->hugepages_kobj
);
1760 nhs
->hugepages_kobj
= NULL
;
1764 * hugetlb module exit: unregister hstate attributes from node devices
1767 static void hugetlb_unregister_all_nodes(void)
1772 * disable node device registrations.
1774 register_hugetlbfs_with_node(NULL
, NULL
);
1777 * remove hstate attributes from any nodes that have them.
1779 for (nid
= 0; nid
< nr_node_ids
; nid
++)
1780 hugetlb_unregister_node(node_devices
[nid
]);
1784 * Register hstate attributes for a single node device.
1785 * No-op if attributes already registered.
1787 static void hugetlb_register_node(struct node
*node
)
1790 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
1793 if (nhs
->hugepages_kobj
)
1794 return; /* already allocated */
1796 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
1798 if (!nhs
->hugepages_kobj
)
1801 for_each_hstate(h
) {
1802 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
1804 &per_node_hstate_attr_group
);
1806 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1807 h
->name
, node
->dev
.id
);
1808 hugetlb_unregister_node(node
);
1815 * hugetlb init time: register hstate attributes for all registered node
1816 * devices of nodes that have memory. All on-line nodes should have
1817 * registered their associated device by this time.
1819 static void hugetlb_register_all_nodes(void)
1823 for_each_node_state(nid
, N_MEMORY
) {
1824 struct node
*node
= node_devices
[nid
];
1825 if (node
->dev
.id
== nid
)
1826 hugetlb_register_node(node
);
1830 * Let the node device driver know we're here so it can
1831 * [un]register hstate attributes on node hotplug.
1833 register_hugetlbfs_with_node(hugetlb_register_node
,
1834 hugetlb_unregister_node
);
1836 #else /* !CONFIG_NUMA */
1838 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
1846 static void hugetlb_unregister_all_nodes(void) { }
1848 static void hugetlb_register_all_nodes(void) { }
1852 static void __exit
hugetlb_exit(void)
1856 hugetlb_unregister_all_nodes();
1858 for_each_hstate(h
) {
1859 kobject_put(hstate_kobjs
[hstate_index(h
)]);
1862 kobject_put(hugepages_kobj
);
1864 module_exit(hugetlb_exit
);
1866 static int __init
hugetlb_init(void)
1868 /* Some platform decide whether they support huge pages at boot
1869 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1870 * there is no such support
1872 if (HPAGE_SHIFT
== 0)
1875 if (!size_to_hstate(default_hstate_size
)) {
1876 default_hstate_size
= HPAGE_SIZE
;
1877 if (!size_to_hstate(default_hstate_size
))
1878 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
1880 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
1881 if (default_hstate_max_huge_pages
)
1882 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
1884 hugetlb_init_hstates();
1885 gather_bootmem_prealloc();
1888 hugetlb_sysfs_init();
1889 hugetlb_register_all_nodes();
1890 hugetlb_cgroup_file_init();
1894 module_init(hugetlb_init
);
1896 /* Should be called on processing a hugepagesz=... option */
1897 void __init
hugetlb_add_hstate(unsigned order
)
1902 if (size_to_hstate(PAGE_SIZE
<< order
)) {
1903 pr_warning("hugepagesz= specified twice, ignoring\n");
1906 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
1908 h
= &hstates
[hugetlb_max_hstate
++];
1910 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
1911 h
->nr_huge_pages
= 0;
1912 h
->free_huge_pages
= 0;
1913 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
1914 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
1915 INIT_LIST_HEAD(&h
->hugepage_activelist
);
1916 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
1917 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
1918 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
1919 huge_page_size(h
)/1024);
1924 static int __init
hugetlb_nrpages_setup(char *s
)
1927 static unsigned long *last_mhp
;
1930 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1931 * so this hugepages= parameter goes to the "default hstate".
1933 if (!hugetlb_max_hstate
)
1934 mhp
= &default_hstate_max_huge_pages
;
1936 mhp
= &parsed_hstate
->max_huge_pages
;
1938 if (mhp
== last_mhp
) {
1939 pr_warning("hugepages= specified twice without "
1940 "interleaving hugepagesz=, ignoring\n");
1944 if (sscanf(s
, "%lu", mhp
) <= 0)
1948 * Global state is always initialized later in hugetlb_init.
1949 * But we need to allocate >= MAX_ORDER hstates here early to still
1950 * use the bootmem allocator.
1952 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
1953 hugetlb_hstate_alloc_pages(parsed_hstate
);
1959 __setup("hugepages=", hugetlb_nrpages_setup
);
1961 static int __init
hugetlb_default_setup(char *s
)
1963 default_hstate_size
= memparse(s
, &s
);
1966 __setup("default_hugepagesz=", hugetlb_default_setup
);
1968 static unsigned int cpuset_mems_nr(unsigned int *array
)
1971 unsigned int nr
= 0;
1973 for_each_node_mask(node
, cpuset_current_mems_allowed
)
1979 #ifdef CONFIG_SYSCTL
1980 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
1981 struct ctl_table
*table
, int write
,
1982 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
1984 struct hstate
*h
= &default_hstate
;
1988 tmp
= h
->max_huge_pages
;
1990 if (write
&& h
->order
>= MAX_ORDER
)
1994 table
->maxlen
= sizeof(unsigned long);
1995 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2000 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
,
2001 GFP_KERNEL
| __GFP_NORETRY
);
2002 if (!(obey_mempolicy
&&
2003 init_nodemask_of_mempolicy(nodes_allowed
))) {
2004 NODEMASK_FREE(nodes_allowed
);
2005 nodes_allowed
= &node_states
[N_MEMORY
];
2007 h
->max_huge_pages
= set_max_huge_pages(h
, tmp
, nodes_allowed
);
2009 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2010 NODEMASK_FREE(nodes_allowed
);
2016 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2017 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2020 return hugetlb_sysctl_handler_common(false, table
, write
,
2021 buffer
, length
, ppos
);
2025 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2026 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2028 return hugetlb_sysctl_handler_common(true, table
, write
,
2029 buffer
, length
, ppos
);
2031 #endif /* CONFIG_NUMA */
2033 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
2034 void __user
*buffer
,
2035 size_t *length
, loff_t
*ppos
)
2037 proc_dointvec(table
, write
, buffer
, length
, ppos
);
2038 if (hugepages_treat_as_movable
)
2039 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
2041 htlb_alloc_mask
= GFP_HIGHUSER
;
2045 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2046 void __user
*buffer
,
2047 size_t *length
, loff_t
*ppos
)
2049 struct hstate
*h
= &default_hstate
;
2053 tmp
= h
->nr_overcommit_huge_pages
;
2055 if (write
&& h
->order
>= MAX_ORDER
)
2059 table
->maxlen
= sizeof(unsigned long);
2060 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2065 spin_lock(&hugetlb_lock
);
2066 h
->nr_overcommit_huge_pages
= tmp
;
2067 spin_unlock(&hugetlb_lock
);
2073 #endif /* CONFIG_SYSCTL */
2075 void hugetlb_report_meminfo(struct seq_file
*m
)
2077 struct hstate
*h
= &default_hstate
;
2079 "HugePages_Total: %5lu\n"
2080 "HugePages_Free: %5lu\n"
2081 "HugePages_Rsvd: %5lu\n"
2082 "HugePages_Surp: %5lu\n"
2083 "Hugepagesize: %8lu kB\n",
2087 h
->surplus_huge_pages
,
2088 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2091 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2093 struct hstate
*h
= &default_hstate
;
2095 "Node %d HugePages_Total: %5u\n"
2096 "Node %d HugePages_Free: %5u\n"
2097 "Node %d HugePages_Surp: %5u\n",
2098 nid
, h
->nr_huge_pages_node
[nid
],
2099 nid
, h
->free_huge_pages_node
[nid
],
2100 nid
, h
->surplus_huge_pages_node
[nid
]);
2103 void hugetlb_show_meminfo(void)
2108 for_each_node_state(nid
, N_MEMORY
)
2110 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2112 h
->nr_huge_pages_node
[nid
],
2113 h
->free_huge_pages_node
[nid
],
2114 h
->surplus_huge_pages_node
[nid
],
2115 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2118 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2119 unsigned long hugetlb_total_pages(void)
2122 unsigned long nr_total_pages
= 0;
2125 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2126 return nr_total_pages
;
2129 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2133 spin_lock(&hugetlb_lock
);
2135 * When cpuset is configured, it breaks the strict hugetlb page
2136 * reservation as the accounting is done on a global variable. Such
2137 * reservation is completely rubbish in the presence of cpuset because
2138 * the reservation is not checked against page availability for the
2139 * current cpuset. Application can still potentially OOM'ed by kernel
2140 * with lack of free htlb page in cpuset that the task is in.
2141 * Attempt to enforce strict accounting with cpuset is almost
2142 * impossible (or too ugly) because cpuset is too fluid that
2143 * task or memory node can be dynamically moved between cpusets.
2145 * The change of semantics for shared hugetlb mapping with cpuset is
2146 * undesirable. However, in order to preserve some of the semantics,
2147 * we fall back to check against current free page availability as
2148 * a best attempt and hopefully to minimize the impact of changing
2149 * semantics that cpuset has.
2152 if (gather_surplus_pages(h
, delta
) < 0)
2155 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2156 return_unused_surplus_pages(h
, delta
);
2163 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2166 spin_unlock(&hugetlb_lock
);
2170 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2172 struct resv_map
*reservations
= vma_resv_map(vma
);
2175 * This new VMA should share its siblings reservation map if present.
2176 * The VMA will only ever have a valid reservation map pointer where
2177 * it is being copied for another still existing VMA. As that VMA
2178 * has a reference to the reservation map it cannot disappear until
2179 * after this open call completes. It is therefore safe to take a
2180 * new reference here without additional locking.
2183 kref_get(&reservations
->refs
);
2186 static void resv_map_put(struct vm_area_struct
*vma
)
2188 struct resv_map
*reservations
= vma_resv_map(vma
);
2192 kref_put(&reservations
->refs
, resv_map_release
);
2195 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2197 struct hstate
*h
= hstate_vma(vma
);
2198 struct resv_map
*reservations
= vma_resv_map(vma
);
2199 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2200 unsigned long reserve
;
2201 unsigned long start
;
2205 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2206 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2208 reserve
= (end
- start
) -
2209 region_count(&reservations
->regions
, start
, end
);
2214 hugetlb_acct_memory(h
, -reserve
);
2215 hugepage_subpool_put_pages(spool
, reserve
);
2221 * We cannot handle pagefaults against hugetlb pages at all. They cause
2222 * handle_mm_fault() to try to instantiate regular-sized pages in the
2223 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2226 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2232 const struct vm_operations_struct hugetlb_vm_ops
= {
2233 .fault
= hugetlb_vm_op_fault
,
2234 .open
= hugetlb_vm_op_open
,
2235 .close
= hugetlb_vm_op_close
,
2238 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
2244 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
2245 vma
->vm_page_prot
)));
2247 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
2248 vma
->vm_page_prot
));
2250 entry
= pte_mkyoung(entry
);
2251 entry
= pte_mkhuge(entry
);
2252 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
2257 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
2258 unsigned long address
, pte_t
*ptep
)
2262 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
2263 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
2264 update_mmu_cache(vma
, address
, ptep
);
2268 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
2269 struct vm_area_struct
*vma
)
2271 pte_t
*src_pte
, *dst_pte
, entry
;
2272 struct page
*ptepage
;
2275 struct hstate
*h
= hstate_vma(vma
);
2276 unsigned long sz
= huge_page_size(h
);
2278 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
2280 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
2281 src_pte
= huge_pte_offset(src
, addr
);
2284 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
2288 /* If the pagetables are shared don't copy or take references */
2289 if (dst_pte
== src_pte
)
2292 spin_lock(&dst
->page_table_lock
);
2293 spin_lock_nested(&src
->page_table_lock
, SINGLE_DEPTH_NESTING
);
2294 if (!huge_pte_none(huge_ptep_get(src_pte
))) {
2296 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
2297 entry
= huge_ptep_get(src_pte
);
2298 ptepage
= pte_page(entry
);
2300 page_dup_rmap(ptepage
);
2301 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
2303 spin_unlock(&src
->page_table_lock
);
2304 spin_unlock(&dst
->page_table_lock
);
2312 static int is_hugetlb_entry_migration(pte_t pte
)
2316 if (huge_pte_none(pte
) || pte_present(pte
))
2318 swp
= pte_to_swp_entry(pte
);
2319 if (non_swap_entry(swp
) && is_migration_entry(swp
))
2325 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
2329 if (huge_pte_none(pte
) || pte_present(pte
))
2331 swp
= pte_to_swp_entry(pte
);
2332 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
2338 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
2339 unsigned long start
, unsigned long end
,
2340 struct page
*ref_page
)
2342 int force_flush
= 0;
2343 struct mm_struct
*mm
= vma
->vm_mm
;
2344 unsigned long address
;
2348 struct hstate
*h
= hstate_vma(vma
);
2349 unsigned long sz
= huge_page_size(h
);
2350 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
2351 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
2353 WARN_ON(!is_vm_hugetlb_page(vma
));
2354 BUG_ON(start
& ~huge_page_mask(h
));
2355 BUG_ON(end
& ~huge_page_mask(h
));
2357 tlb_start_vma(tlb
, vma
);
2358 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2360 spin_lock(&mm
->page_table_lock
);
2361 for (address
= start
; address
< end
; address
+= sz
) {
2362 ptep
= huge_pte_offset(mm
, address
);
2366 if (huge_pmd_unshare(mm
, &address
, ptep
))
2369 pte
= huge_ptep_get(ptep
);
2370 if (huge_pte_none(pte
))
2374 * HWPoisoned hugepage is already unmapped and dropped reference
2376 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
2377 huge_pte_clear(mm
, address
, ptep
);
2381 page
= pte_page(pte
);
2383 * If a reference page is supplied, it is because a specific
2384 * page is being unmapped, not a range. Ensure the page we
2385 * are about to unmap is the actual page of interest.
2388 if (page
!= ref_page
)
2392 * Mark the VMA as having unmapped its page so that
2393 * future faults in this VMA will fail rather than
2394 * looking like data was lost
2396 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
2399 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
2400 tlb_remove_tlb_entry(tlb
, ptep
, address
);
2401 if (huge_pte_dirty(pte
))
2402 set_page_dirty(page
);
2404 page_remove_rmap(page
);
2405 force_flush
= !__tlb_remove_page(tlb
, page
);
2408 /* Bail out after unmapping reference page if supplied */
2412 spin_unlock(&mm
->page_table_lock
);
2414 * mmu_gather ran out of room to batch pages, we break out of
2415 * the PTE lock to avoid doing the potential expensive TLB invalidate
2416 * and page-free while holding it.
2421 if (address
< end
&& !ref_page
)
2424 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2425 tlb_end_vma(tlb
, vma
);
2428 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
2429 struct vm_area_struct
*vma
, unsigned long start
,
2430 unsigned long end
, struct page
*ref_page
)
2432 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
2435 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2436 * test will fail on a vma being torn down, and not grab a page table
2437 * on its way out. We're lucky that the flag has such an appropriate
2438 * name, and can in fact be safely cleared here. We could clear it
2439 * before the __unmap_hugepage_range above, but all that's necessary
2440 * is to clear it before releasing the i_mmap_mutex. This works
2441 * because in the context this is called, the VMA is about to be
2442 * destroyed and the i_mmap_mutex is held.
2444 vma
->vm_flags
&= ~VM_MAYSHARE
;
2447 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
2448 unsigned long end
, struct page
*ref_page
)
2450 struct mm_struct
*mm
;
2451 struct mmu_gather tlb
;
2455 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2456 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
2457 tlb_finish_mmu(&tlb
, start
, end
);
2461 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2462 * mappping it owns the reserve page for. The intention is to unmap the page
2463 * from other VMAs and let the children be SIGKILLed if they are faulting the
2466 static int unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2467 struct page
*page
, unsigned long address
)
2469 struct hstate
*h
= hstate_vma(vma
);
2470 struct vm_area_struct
*iter_vma
;
2471 struct address_space
*mapping
;
2475 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2476 * from page cache lookup which is in HPAGE_SIZE units.
2478 address
= address
& huge_page_mask(h
);
2479 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
2481 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
2484 * Take the mapping lock for the duration of the table walk. As
2485 * this mapping should be shared between all the VMAs,
2486 * __unmap_hugepage_range() is called as the lock is already held
2488 mutex_lock(&mapping
->i_mmap_mutex
);
2489 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
2490 /* Do not unmap the current VMA */
2491 if (iter_vma
== vma
)
2495 * Unmap the page from other VMAs without their own reserves.
2496 * They get marked to be SIGKILLed if they fault in these
2497 * areas. This is because a future no-page fault on this VMA
2498 * could insert a zeroed page instead of the data existing
2499 * from the time of fork. This would look like data corruption
2501 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
2502 unmap_hugepage_range(iter_vma
, address
,
2503 address
+ huge_page_size(h
), page
);
2505 mutex_unlock(&mapping
->i_mmap_mutex
);
2511 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2512 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2513 * cannot race with other handlers or page migration.
2514 * Keep the pte_same checks anyway to make transition from the mutex easier.
2516 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2517 unsigned long address
, pte_t
*ptep
, pte_t pte
,
2518 struct page
*pagecache_page
)
2520 struct hstate
*h
= hstate_vma(vma
);
2521 struct page
*old_page
, *new_page
;
2522 int outside_reserve
= 0;
2523 unsigned long mmun_start
; /* For mmu_notifiers */
2524 unsigned long mmun_end
; /* For mmu_notifiers */
2526 old_page
= pte_page(pte
);
2529 /* If no-one else is actually using this page, avoid the copy
2530 * and just make the page writable */
2531 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
2532 page_move_anon_rmap(old_page
, vma
, address
);
2533 set_huge_ptep_writable(vma
, address
, ptep
);
2538 * If the process that created a MAP_PRIVATE mapping is about to
2539 * perform a COW due to a shared page count, attempt to satisfy
2540 * the allocation without using the existing reserves. The pagecache
2541 * page is used to determine if the reserve at this address was
2542 * consumed or not. If reserves were used, a partial faulted mapping
2543 * at the time of fork() could consume its reserves on COW instead
2544 * of the full address range.
2546 if (!(vma
->vm_flags
& VM_MAYSHARE
) &&
2547 is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
2548 old_page
!= pagecache_page
)
2549 outside_reserve
= 1;
2551 page_cache_get(old_page
);
2553 /* Drop page_table_lock as buddy allocator may be called */
2554 spin_unlock(&mm
->page_table_lock
);
2555 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
2557 if (IS_ERR(new_page
)) {
2558 long err
= PTR_ERR(new_page
);
2559 page_cache_release(old_page
);
2562 * If a process owning a MAP_PRIVATE mapping fails to COW,
2563 * it is due to references held by a child and an insufficient
2564 * huge page pool. To guarantee the original mappers
2565 * reliability, unmap the page from child processes. The child
2566 * may get SIGKILLed if it later faults.
2568 if (outside_reserve
) {
2569 BUG_ON(huge_pte_none(pte
));
2570 if (unmap_ref_private(mm
, vma
, old_page
, address
)) {
2571 BUG_ON(huge_pte_none(pte
));
2572 spin_lock(&mm
->page_table_lock
);
2573 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2574 if (likely(pte_same(huge_ptep_get(ptep
), pte
)))
2575 goto retry_avoidcopy
;
2577 * race occurs while re-acquiring page_table_lock, and
2585 /* Caller expects lock to be held */
2586 spin_lock(&mm
->page_table_lock
);
2588 return VM_FAULT_OOM
;
2590 return VM_FAULT_SIGBUS
;
2594 * When the original hugepage is shared one, it does not have
2595 * anon_vma prepared.
2597 if (unlikely(anon_vma_prepare(vma
))) {
2598 page_cache_release(new_page
);
2599 page_cache_release(old_page
);
2600 /* Caller expects lock to be held */
2601 spin_lock(&mm
->page_table_lock
);
2602 return VM_FAULT_OOM
;
2605 copy_user_huge_page(new_page
, old_page
, address
, vma
,
2606 pages_per_huge_page(h
));
2607 __SetPageUptodate(new_page
);
2609 mmun_start
= address
& huge_page_mask(h
);
2610 mmun_end
= mmun_start
+ huge_page_size(h
);
2611 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2613 * Retake the page_table_lock to check for racing updates
2614 * before the page tables are altered
2616 spin_lock(&mm
->page_table_lock
);
2617 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
2618 if (likely(pte_same(huge_ptep_get(ptep
), pte
))) {
2620 huge_ptep_clear_flush(vma
, address
, ptep
);
2621 set_huge_pte_at(mm
, address
, ptep
,
2622 make_huge_pte(vma
, new_page
, 1));
2623 page_remove_rmap(old_page
);
2624 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
2625 /* Make the old page be freed below */
2626 new_page
= old_page
;
2628 spin_unlock(&mm
->page_table_lock
);
2629 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2630 /* Caller expects lock to be held */
2631 spin_lock(&mm
->page_table_lock
);
2632 page_cache_release(new_page
);
2633 page_cache_release(old_page
);
2637 /* Return the pagecache page at a given address within a VMA */
2638 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
2639 struct vm_area_struct
*vma
, unsigned long address
)
2641 struct address_space
*mapping
;
2644 mapping
= vma
->vm_file
->f_mapping
;
2645 idx
= vma_hugecache_offset(h
, vma
, address
);
2647 return find_lock_page(mapping
, idx
);
2651 * Return whether there is a pagecache page to back given address within VMA.
2652 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2654 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
2655 struct vm_area_struct
*vma
, unsigned long address
)
2657 struct address_space
*mapping
;
2661 mapping
= vma
->vm_file
->f_mapping
;
2662 idx
= vma_hugecache_offset(h
, vma
, address
);
2664 page
= find_get_page(mapping
, idx
);
2667 return page
!= NULL
;
2670 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2671 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
2673 struct hstate
*h
= hstate_vma(vma
);
2674 int ret
= VM_FAULT_SIGBUS
;
2679 struct address_space
*mapping
;
2683 * Currently, we are forced to kill the process in the event the
2684 * original mapper has unmapped pages from the child due to a failed
2685 * COW. Warn that such a situation has occurred as it may not be obvious
2687 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
2688 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2693 mapping
= vma
->vm_file
->f_mapping
;
2694 idx
= vma_hugecache_offset(h
, vma
, address
);
2697 * Use page lock to guard against racing truncation
2698 * before we get page_table_lock.
2701 page
= find_lock_page(mapping
, idx
);
2703 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2706 page
= alloc_huge_page(vma
, address
, 0);
2708 ret
= PTR_ERR(page
);
2712 ret
= VM_FAULT_SIGBUS
;
2715 clear_huge_page(page
, address
, pages_per_huge_page(h
));
2716 __SetPageUptodate(page
);
2718 if (vma
->vm_flags
& VM_MAYSHARE
) {
2720 struct inode
*inode
= mapping
->host
;
2722 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
2730 spin_lock(&inode
->i_lock
);
2731 inode
->i_blocks
+= blocks_per_huge_page(h
);
2732 spin_unlock(&inode
->i_lock
);
2735 if (unlikely(anon_vma_prepare(vma
))) {
2737 goto backout_unlocked
;
2743 * If memory error occurs between mmap() and fault, some process
2744 * don't have hwpoisoned swap entry for errored virtual address.
2745 * So we need to block hugepage fault by PG_hwpoison bit check.
2747 if (unlikely(PageHWPoison(page
))) {
2748 ret
= VM_FAULT_HWPOISON
|
2749 VM_FAULT_SET_HINDEX(hstate_index(h
));
2750 goto backout_unlocked
;
2755 * If we are going to COW a private mapping later, we examine the
2756 * pending reservations for this page now. This will ensure that
2757 * any allocations necessary to record that reservation occur outside
2760 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
))
2761 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2763 goto backout_unlocked
;
2766 spin_lock(&mm
->page_table_lock
);
2767 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
2772 if (!huge_pte_none(huge_ptep_get(ptep
)))
2776 hugepage_add_new_anon_rmap(page
, vma
, address
);
2778 page_dup_rmap(page
);
2779 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
2780 && (vma
->vm_flags
& VM_SHARED
)));
2781 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
2783 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
2784 /* Optimization, do the COW without a second fault */
2785 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
);
2788 spin_unlock(&mm
->page_table_lock
);
2794 spin_unlock(&mm
->page_table_lock
);
2801 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2802 unsigned long address
, unsigned int flags
)
2807 struct page
*page
= NULL
;
2808 struct page
*pagecache_page
= NULL
;
2809 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
2810 struct hstate
*h
= hstate_vma(vma
);
2812 address
&= huge_page_mask(h
);
2814 ptep
= huge_pte_offset(mm
, address
);
2816 entry
= huge_ptep_get(ptep
);
2817 if (unlikely(is_hugetlb_entry_migration(entry
))) {
2818 migration_entry_wait_huge(mm
, ptep
);
2820 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
2821 return VM_FAULT_HWPOISON_LARGE
|
2822 VM_FAULT_SET_HINDEX(hstate_index(h
));
2825 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
2827 return VM_FAULT_OOM
;
2830 * Serialize hugepage allocation and instantiation, so that we don't
2831 * get spurious allocation failures if two CPUs race to instantiate
2832 * the same page in the page cache.
2834 mutex_lock(&hugetlb_instantiation_mutex
);
2835 entry
= huge_ptep_get(ptep
);
2836 if (huge_pte_none(entry
)) {
2837 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, flags
);
2844 * If we are going to COW the mapping later, we examine the pending
2845 * reservations for this page now. This will ensure that any
2846 * allocations necessary to record that reservation occur outside the
2847 * spinlock. For private mappings, we also lookup the pagecache
2848 * page now as it is used to determine if a reservation has been
2851 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
2852 if (vma_needs_reservation(h
, vma
, address
) < 0) {
2857 if (!(vma
->vm_flags
& VM_MAYSHARE
))
2858 pagecache_page
= hugetlbfs_pagecache_page(h
,
2863 * hugetlb_cow() requires page locks of pte_page(entry) and
2864 * pagecache_page, so here we need take the former one
2865 * when page != pagecache_page or !pagecache_page.
2866 * Note that locking order is always pagecache_page -> page,
2867 * so no worry about deadlock.
2869 page
= pte_page(entry
);
2871 if (page
!= pagecache_page
)
2874 spin_lock(&mm
->page_table_lock
);
2875 /* Check for a racing update before calling hugetlb_cow */
2876 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
2877 goto out_page_table_lock
;
2880 if (flags
& FAULT_FLAG_WRITE
) {
2881 if (!huge_pte_write(entry
)) {
2882 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
2884 goto out_page_table_lock
;
2886 entry
= huge_pte_mkdirty(entry
);
2888 entry
= pte_mkyoung(entry
);
2889 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
2890 flags
& FAULT_FLAG_WRITE
))
2891 update_mmu_cache(vma
, address
, ptep
);
2893 out_page_table_lock
:
2894 spin_unlock(&mm
->page_table_lock
);
2896 if (pagecache_page
) {
2897 unlock_page(pagecache_page
);
2898 put_page(pagecache_page
);
2900 if (page
!= pagecache_page
)
2905 mutex_unlock(&hugetlb_instantiation_mutex
);
2910 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2911 struct page
**pages
, struct vm_area_struct
**vmas
,
2912 unsigned long *position
, unsigned long *nr_pages
,
2913 long i
, unsigned int flags
)
2915 unsigned long pfn_offset
;
2916 unsigned long vaddr
= *position
;
2917 unsigned long remainder
= *nr_pages
;
2918 struct hstate
*h
= hstate_vma(vma
);
2920 spin_lock(&mm
->page_table_lock
);
2921 while (vaddr
< vma
->vm_end
&& remainder
) {
2927 * Some archs (sparc64, sh*) have multiple pte_ts to
2928 * each hugepage. We have to make sure we get the
2929 * first, for the page indexing below to work.
2931 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
2932 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
2935 * When coredumping, it suits get_dump_page if we just return
2936 * an error where there's an empty slot with no huge pagecache
2937 * to back it. This way, we avoid allocating a hugepage, and
2938 * the sparse dumpfile avoids allocating disk blocks, but its
2939 * huge holes still show up with zeroes where they need to be.
2941 if (absent
&& (flags
& FOLL_DUMP
) &&
2942 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
2948 * We need call hugetlb_fault for both hugepages under migration
2949 * (in which case hugetlb_fault waits for the migration,) and
2950 * hwpoisoned hugepages (in which case we need to prevent the
2951 * caller from accessing to them.) In order to do this, we use
2952 * here is_swap_pte instead of is_hugetlb_entry_migration and
2953 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
2954 * both cases, and because we can't follow correct pages
2955 * directly from any kind of swap entries.
2957 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
2958 ((flags
& FOLL_WRITE
) &&
2959 !huge_pte_write(huge_ptep_get(pte
)))) {
2962 spin_unlock(&mm
->page_table_lock
);
2963 ret
= hugetlb_fault(mm
, vma
, vaddr
,
2964 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
2965 spin_lock(&mm
->page_table_lock
);
2966 if (!(ret
& VM_FAULT_ERROR
))
2973 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
2974 page
= pte_page(huge_ptep_get(pte
));
2977 pages
[i
] = mem_map_offset(page
, pfn_offset
);
2988 if (vaddr
< vma
->vm_end
&& remainder
&&
2989 pfn_offset
< pages_per_huge_page(h
)) {
2991 * We use pfn_offset to avoid touching the pageframes
2992 * of this compound page.
2997 spin_unlock(&mm
->page_table_lock
);
2998 *nr_pages
= remainder
;
3001 return i
? i
: -EFAULT
;
3004 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3005 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3007 struct mm_struct
*mm
= vma
->vm_mm
;
3008 unsigned long start
= address
;
3011 struct hstate
*h
= hstate_vma(vma
);
3012 unsigned long pages
= 0;
3014 BUG_ON(address
>= end
);
3015 flush_cache_range(vma
, address
, end
);
3017 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3018 spin_lock(&mm
->page_table_lock
);
3019 for (; address
< end
; address
+= huge_page_size(h
)) {
3020 ptep
= huge_pte_offset(mm
, address
);
3023 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3027 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3028 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3029 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3030 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3031 set_huge_pte_at(mm
, address
, ptep
, pte
);
3035 spin_unlock(&mm
->page_table_lock
);
3037 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3038 * may have cleared our pud entry and done put_page on the page table:
3039 * once we release i_mmap_mutex, another task can do the final put_page
3040 * and that page table be reused and filled with junk.
3042 flush_tlb_range(vma
, start
, end
);
3043 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
3045 return pages
<< h
->order
;
3048 int hugetlb_reserve_pages(struct inode
*inode
,
3050 struct vm_area_struct
*vma
,
3051 vm_flags_t vm_flags
)
3054 struct hstate
*h
= hstate_inode(inode
);
3055 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3058 * Only apply hugepage reservation if asked. At fault time, an
3059 * attempt will be made for VM_NORESERVE to allocate a page
3060 * without using reserves
3062 if (vm_flags
& VM_NORESERVE
)
3066 * Shared mappings base their reservation on the number of pages that
3067 * are already allocated on behalf of the file. Private mappings need
3068 * to reserve the full area even if read-only as mprotect() may be
3069 * called to make the mapping read-write. Assume !vma is a shm mapping
3071 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3072 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
3074 struct resv_map
*resv_map
= resv_map_alloc();
3080 set_vma_resv_map(vma
, resv_map
);
3081 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
3089 /* There must be enough pages in the subpool for the mapping */
3090 if (hugepage_subpool_get_pages(spool
, chg
)) {
3096 * Check enough hugepages are available for the reservation.
3097 * Hand the pages back to the subpool if there are not
3099 ret
= hugetlb_acct_memory(h
, chg
);
3101 hugepage_subpool_put_pages(spool
, chg
);
3106 * Account for the reservations made. Shared mappings record regions
3107 * that have reservations as they are shared by multiple VMAs.
3108 * When the last VMA disappears, the region map says how much
3109 * the reservation was and the page cache tells how much of
3110 * the reservation was consumed. Private mappings are per-VMA and
3111 * only the consumed reservations are tracked. When the VMA
3112 * disappears, the original reservation is the VMA size and the
3113 * consumed reservations are stored in the map. Hence, nothing
3114 * else has to be done for private mappings here
3116 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
3117 region_add(&inode
->i_mapping
->private_list
, from
, to
);
3125 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
3127 struct hstate
*h
= hstate_inode(inode
);
3128 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
3129 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3131 spin_lock(&inode
->i_lock
);
3132 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
3133 spin_unlock(&inode
->i_lock
);
3135 hugepage_subpool_put_pages(spool
, (chg
- freed
));
3136 hugetlb_acct_memory(h
, -(chg
- freed
));
3139 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3140 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
3141 struct vm_area_struct
*vma
,
3142 unsigned long addr
, pgoff_t idx
)
3144 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
3146 unsigned long sbase
= saddr
& PUD_MASK
;
3147 unsigned long s_end
= sbase
+ PUD_SIZE
;
3149 /* Allow segments to share if only one is marked locked */
3150 unsigned long vm_flags
= vma
->vm_flags
& ~VM_LOCKED
;
3151 unsigned long svm_flags
= svma
->vm_flags
& ~VM_LOCKED
;
3154 * match the virtual addresses, permission and the alignment of the
3157 if (pmd_index(addr
) != pmd_index(saddr
) ||
3158 vm_flags
!= svm_flags
||
3159 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
3165 static int vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
3167 unsigned long base
= addr
& PUD_MASK
;
3168 unsigned long end
= base
+ PUD_SIZE
;
3171 * check on proper vm_flags and page table alignment
3173 if (vma
->vm_flags
& VM_MAYSHARE
&&
3174 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
3180 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3181 * and returns the corresponding pte. While this is not necessary for the
3182 * !shared pmd case because we can allocate the pmd later as well, it makes the
3183 * code much cleaner. pmd allocation is essential for the shared case because
3184 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3185 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3186 * bad pmd for sharing.
3188 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3190 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
3191 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3192 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
3194 struct vm_area_struct
*svma
;
3195 unsigned long saddr
;
3199 if (!vma_shareable(vma
, addr
))
3200 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3202 mutex_lock(&mapping
->i_mmap_mutex
);
3203 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
3207 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
3209 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
3211 get_page(virt_to_page(spte
));
3220 spin_lock(&mm
->page_table_lock
);
3222 pud_populate(mm
, pud
,
3223 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
3225 put_page(virt_to_page(spte
));
3226 spin_unlock(&mm
->page_table_lock
);
3228 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3229 mutex_unlock(&mapping
->i_mmap_mutex
);
3234 * unmap huge page backed by shared pte.
3236 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3237 * indicated by page_count > 1, unmap is achieved by clearing pud and
3238 * decrementing the ref count. If count == 1, the pte page is not shared.
3240 * called with vma->vm_mm->page_table_lock held.
3242 * returns: 1 successfully unmapped a shared pte page
3243 * 0 the underlying pte page is not shared, or it is the last user
3245 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
3247 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
3248 pud_t
*pud
= pud_offset(pgd
, *addr
);
3250 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
3251 if (page_count(virt_to_page(ptep
)) == 1)
3255 put_page(virt_to_page(ptep
));
3256 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
3259 #define want_pmd_share() (1)
3260 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3261 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
3265 #define want_pmd_share() (0)
3266 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3268 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3269 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
3270 unsigned long addr
, unsigned long sz
)
3276 pgd
= pgd_offset(mm
, addr
);
3277 pud
= pud_alloc(mm
, pgd
, addr
);
3279 if (sz
== PUD_SIZE
) {
3282 BUG_ON(sz
!= PMD_SIZE
);
3283 if (want_pmd_share() && pud_none(*pud
))
3284 pte
= huge_pmd_share(mm
, addr
, pud
);
3286 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
3289 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
3294 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
3300 pgd
= pgd_offset(mm
, addr
);
3301 if (pgd_present(*pgd
)) {
3302 pud
= pud_offset(pgd
, addr
);
3303 if (pud_present(*pud
)) {
3305 return (pte_t
*)pud
;
3306 pmd
= pmd_offset(pud
, addr
);
3309 return (pte_t
*) pmd
;
3313 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
3314 pmd_t
*pmd
, int write
)
3318 page
= pte_page(*(pte_t
*)pmd
);
3320 page
+= ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
3325 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3326 pud_t
*pud
, int write
)
3330 page
= pte_page(*(pte_t
*)pud
);
3332 page
+= ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
3336 #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3338 /* Can be overriden by architectures */
3339 __attribute__((weak
)) struct page
*
3340 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
3341 pud_t
*pud
, int write
)
3347 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3349 #ifdef CONFIG_MEMORY_FAILURE
3351 /* Should be called in hugetlb_lock */
3352 static int is_hugepage_on_freelist(struct page
*hpage
)
3356 struct hstate
*h
= page_hstate(hpage
);
3357 int nid
= page_to_nid(hpage
);
3359 list_for_each_entry_safe(page
, tmp
, &h
->hugepage_freelists
[nid
], lru
)
3366 * This function is called from memory failure code.
3367 * Assume the caller holds page lock of the head page.
3369 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
3371 struct hstate
*h
= page_hstate(hpage
);
3372 int nid
= page_to_nid(hpage
);
3375 spin_lock(&hugetlb_lock
);
3376 if (is_hugepage_on_freelist(hpage
)) {
3378 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3379 * but dangling hpage->lru can trigger list-debug warnings
3380 * (this happens when we call unpoison_memory() on it),
3381 * so let it point to itself with list_del_init().
3383 list_del_init(&hpage
->lru
);
3384 set_page_refcounted(hpage
);
3385 h
->free_huge_pages
--;
3386 h
->free_huge_pages_node
[nid
]--;
3389 spin_unlock(&hugetlb_lock
);