2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/bootmem.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
38 int hugepages_treat_as_movable
;
40 int hugetlb_max_hstate __read_mostly
;
41 unsigned int default_hstate_idx
;
42 struct hstate hstates
[HUGE_MAX_HSTATE
];
44 * Minimum page order among possible hugepage sizes, set to a proper value
47 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
49 __initdata
LIST_HEAD(huge_boot_pages
);
51 /* for command line parsing */
52 static struct hstate
* __initdata parsed_hstate
;
53 static unsigned long __initdata default_hstate_max_huge_pages
;
54 static unsigned long __initdata default_hstate_size
;
57 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
58 * free_huge_pages, and surplus_huge_pages.
60 DEFINE_SPINLOCK(hugetlb_lock
);
63 * Serializes faults on the same logical page. This is used to
64 * prevent spurious OOMs when the hugepage pool is fully utilized.
66 static int num_fault_mutexes
;
67 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
69 /* Forward declaration */
70 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
72 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
74 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
76 spin_unlock(&spool
->lock
);
78 /* If no pages are used, and no other handles to the subpool
79 * remain, give up any reservations mased on minimum size and
82 if (spool
->min_hpages
!= -1)
83 hugetlb_acct_memory(spool
->hstate
,
89 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
92 struct hugepage_subpool
*spool
;
94 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
98 spin_lock_init(&spool
->lock
);
100 spool
->max_hpages
= max_hpages
;
102 spool
->min_hpages
= min_hpages
;
104 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
108 spool
->rsv_hpages
= min_hpages
;
113 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
115 spin_lock(&spool
->lock
);
116 BUG_ON(!spool
->count
);
118 unlock_or_release_subpool(spool
);
122 * Subpool accounting for allocating and reserving pages.
123 * Return -ENOMEM if there are not enough resources to satisfy the
124 * the request. Otherwise, return the number of pages by which the
125 * global pools must be adjusted (upward). The returned value may
126 * only be different than the passed value (delta) in the case where
127 * a subpool minimum size must be manitained.
129 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
137 spin_lock(&spool
->lock
);
139 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
140 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
141 spool
->used_hpages
+= delta
;
148 if (spool
->min_hpages
!= -1) { /* minimum size accounting */
149 if (delta
> spool
->rsv_hpages
) {
151 * Asking for more reserves than those already taken on
152 * behalf of subpool. Return difference.
154 ret
= delta
- spool
->rsv_hpages
;
155 spool
->rsv_hpages
= 0;
157 ret
= 0; /* reserves already accounted for */
158 spool
->rsv_hpages
-= delta
;
163 spin_unlock(&spool
->lock
);
168 * Subpool accounting for freeing and unreserving pages.
169 * Return the number of global page reservations that must be dropped.
170 * The return value may only be different than the passed value (delta)
171 * in the case where a subpool minimum size must be maintained.
173 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
181 spin_lock(&spool
->lock
);
183 if (spool
->max_hpages
!= -1) /* maximum size accounting */
184 spool
->used_hpages
-= delta
;
186 if (spool
->min_hpages
!= -1) { /* minimum size accounting */
187 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
190 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
192 spool
->rsv_hpages
+= delta
;
193 if (spool
->rsv_hpages
> spool
->min_hpages
)
194 spool
->rsv_hpages
= spool
->min_hpages
;
198 * If hugetlbfs_put_super couldn't free spool due to an outstanding
199 * quota reference, free it now.
201 unlock_or_release_subpool(spool
);
206 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
208 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
211 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
213 return subpool_inode(file_inode(vma
->vm_file
));
217 * Region tracking -- allows tracking of reservations and instantiated pages
218 * across the pages in a mapping.
220 * The region data structures are embedded into a resv_map and protected
221 * by a resv_map's lock. The set of regions within the resv_map represent
222 * reservations for huge pages, or huge pages that have already been
223 * instantiated within the map. The from and to elements are huge page
224 * indicies into the associated mapping. from indicates the starting index
225 * of the region. to represents the first index past the end of the region.
227 * For example, a file region structure with from == 0 and to == 4 represents
228 * four huge pages in a mapping. It is important to note that the to element
229 * represents the first element past the end of the region. This is used in
230 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
232 * Interval notation of the form [from, to) will be used to indicate that
233 * the endpoint from is inclusive and to is exclusive.
236 struct list_head link
;
242 * Add the huge page range represented by [f, t) to the reserve
243 * map. In the normal case, existing regions will be expanded
244 * to accommodate the specified range. Sufficient regions should
245 * exist for expansion due to the previous call to region_chg
246 * with the same range. However, it is possible that region_del
247 * could have been called after region_chg and modifed the map
248 * in such a way that no region exists to be expanded. In this
249 * case, pull a region descriptor from the cache associated with
250 * the map and use that for the new range.
252 * Return the number of new huge pages added to the map. This
253 * number is greater than or equal to zero.
255 static long region_add(struct resv_map
*resv
, long f
, long t
)
257 struct list_head
*head
= &resv
->regions
;
258 struct file_region
*rg
, *nrg
, *trg
;
261 spin_lock(&resv
->lock
);
262 /* Locate the region we are either in or before. */
263 list_for_each_entry(rg
, head
, link
)
268 * If no region exists which can be expanded to include the
269 * specified range, the list must have been modified by an
270 * interleving call to region_del(). Pull a region descriptor
271 * from the cache and use it for this range.
273 if (&rg
->link
== head
|| t
< rg
->from
) {
274 VM_BUG_ON(resv
->region_cache_count
<= 0);
276 resv
->region_cache_count
--;
277 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
279 list_del(&nrg
->link
);
283 list_add(&nrg
->link
, rg
->link
.prev
);
289 /* Round our left edge to the current segment if it encloses us. */
293 /* Check for and consume any regions we now overlap with. */
295 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
296 if (&rg
->link
== head
)
301 /* If this area reaches higher then extend our area to
302 * include it completely. If this is not the first area
303 * which we intend to reuse, free it. */
307 /* Decrement return value by the deleted range.
308 * Another range will span this area so that by
309 * end of routine add will be >= zero
311 add
-= (rg
->to
- rg
->from
);
317 add
+= (nrg
->from
- f
); /* Added to beginning of region */
319 add
+= t
- nrg
->to
; /* Added to end of region */
323 resv
->adds_in_progress
--;
324 spin_unlock(&resv
->lock
);
330 * Examine the existing reserve map and determine how many
331 * huge pages in the specified range [f, t) are NOT currently
332 * represented. This routine is called before a subsequent
333 * call to region_add that will actually modify the reserve
334 * map to add the specified range [f, t). region_chg does
335 * not change the number of huge pages represented by the
336 * map. However, if the existing regions in the map can not
337 * be expanded to represent the new range, a new file_region
338 * structure is added to the map as a placeholder. This is
339 * so that the subsequent region_add call will have all the
340 * regions it needs and will not fail.
342 * Upon entry, region_chg will also examine the cache of region descriptors
343 * associated with the map. If there are not enough descriptors cached, one
344 * will be allocated for the in progress add operation.
346 * Returns the number of huge pages that need to be added to the existing
347 * reservation map for the range [f, t). This number is greater or equal to
348 * zero. -ENOMEM is returned if a new file_region structure or cache entry
349 * is needed and can not be allocated.
351 static long region_chg(struct resv_map
*resv
, long f
, long t
)
353 struct list_head
*head
= &resv
->regions
;
354 struct file_region
*rg
, *nrg
= NULL
;
358 spin_lock(&resv
->lock
);
360 resv
->adds_in_progress
++;
363 * Check for sufficient descriptors in the cache to accommodate
364 * the number of in progress add operations.
366 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
367 struct file_region
*trg
;
369 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
370 /* Must drop lock to allocate a new descriptor. */
371 resv
->adds_in_progress
--;
372 spin_unlock(&resv
->lock
);
374 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
378 spin_lock(&resv
->lock
);
379 list_add(&trg
->link
, &resv
->region_cache
);
380 resv
->region_cache_count
++;
384 /* Locate the region we are before or in. */
385 list_for_each_entry(rg
, head
, link
)
389 /* If we are below the current region then a new region is required.
390 * Subtle, allocate a new region at the position but make it zero
391 * size such that we can guarantee to record the reservation. */
392 if (&rg
->link
== head
|| t
< rg
->from
) {
394 resv
->adds_in_progress
--;
395 spin_unlock(&resv
->lock
);
396 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
402 INIT_LIST_HEAD(&nrg
->link
);
406 list_add(&nrg
->link
, rg
->link
.prev
);
411 /* Round our left edge to the current segment if it encloses us. */
416 /* Check for and consume any regions we now overlap with. */
417 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
418 if (&rg
->link
== head
)
423 /* We overlap with this area, if it extends further than
424 * us then we must extend ourselves. Account for its
425 * existing reservation. */
430 chg
-= rg
->to
- rg
->from
;
434 spin_unlock(&resv
->lock
);
435 /* We already know we raced and no longer need the new region */
439 spin_unlock(&resv
->lock
);
444 * Abort the in progress add operation. The adds_in_progress field
445 * of the resv_map keeps track of the operations in progress between
446 * calls to region_chg and region_add. Operations are sometimes
447 * aborted after the call to region_chg. In such cases, region_abort
448 * is called to decrement the adds_in_progress counter.
450 * NOTE: The range arguments [f, t) are not needed or used in this
451 * routine. They are kept to make reading the calling code easier as
452 * arguments will match the associated region_chg call.
454 static void region_abort(struct resv_map
*resv
, long f
, long t
)
456 spin_lock(&resv
->lock
);
457 VM_BUG_ON(!resv
->region_cache_count
);
458 resv
->adds_in_progress
--;
459 spin_unlock(&resv
->lock
);
463 * Delete the specified range [f, t) from the reserve map. If the
464 * t parameter is LONG_MAX, this indicates that ALL regions after f
465 * should be deleted. Locate the regions which intersect [f, t)
466 * and either trim, delete or split the existing regions.
468 * Returns the number of huge pages deleted from the reserve map.
469 * In the normal case, the return value is zero or more. In the
470 * case where a region must be split, a new region descriptor must
471 * be allocated. If the allocation fails, -ENOMEM will be returned.
472 * NOTE: If the parameter t == LONG_MAX, then we will never split
473 * a region and possibly return -ENOMEM. Callers specifying
474 * t == LONG_MAX do not need to check for -ENOMEM error.
476 static long region_del(struct resv_map
*resv
, long f
, long t
)
478 struct list_head
*head
= &resv
->regions
;
479 struct file_region
*rg
, *trg
;
480 struct file_region
*nrg
= NULL
;
484 spin_lock(&resv
->lock
);
485 list_for_each_entry_safe(rg
, trg
, head
, link
) {
491 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
493 * Check for an entry in the cache before dropping
494 * lock and attempting allocation.
497 resv
->region_cache_count
> resv
->adds_in_progress
) {
498 nrg
= list_first_entry(&resv
->region_cache
,
501 list_del(&nrg
->link
);
502 resv
->region_cache_count
--;
506 spin_unlock(&resv
->lock
);
507 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
515 /* New entry for end of split region */
518 INIT_LIST_HEAD(&nrg
->link
);
520 /* Original entry is trimmed */
523 list_add(&nrg
->link
, &rg
->link
);
528 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
529 del
+= rg
->to
- rg
->from
;
535 if (f
<= rg
->from
) { /* Trim beginning of region */
538 } else { /* Trim end of region */
544 spin_unlock(&resv
->lock
);
550 * A rare out of memory error was encountered which prevented removal of
551 * the reserve map region for a page. The huge page itself was free'ed
552 * and removed from the page cache. This routine will adjust the subpool
553 * usage count, and the global reserve count if needed. By incrementing
554 * these counts, the reserve map entry which could not be deleted will
555 * appear as a "reserved" entry instead of simply dangling with incorrect
558 void hugetlb_fix_reserve_counts(struct inode
*inode
, bool restore_reserve
)
560 struct hugepage_subpool
*spool
= subpool_inode(inode
);
563 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
564 if (restore_reserve
&& rsv_adjust
) {
565 struct hstate
*h
= hstate_inode(inode
);
567 hugetlb_acct_memory(h
, 1);
572 * Count and return the number of huge pages in the reserve map
573 * that intersect with the range [f, t).
575 static long region_count(struct resv_map
*resv
, long f
, long t
)
577 struct list_head
*head
= &resv
->regions
;
578 struct file_region
*rg
;
581 spin_lock(&resv
->lock
);
582 /* Locate each segment we overlap with, and count that overlap. */
583 list_for_each_entry(rg
, head
, link
) {
592 seg_from
= max(rg
->from
, f
);
593 seg_to
= min(rg
->to
, t
);
595 chg
+= seg_to
- seg_from
;
597 spin_unlock(&resv
->lock
);
603 * Convert the address within this vma to the page offset within
604 * the mapping, in pagecache page units; huge pages here.
606 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
607 struct vm_area_struct
*vma
, unsigned long address
)
609 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
610 (vma
->vm_pgoff
>> huge_page_order(h
));
613 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
614 unsigned long address
)
616 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
620 * Return the size of the pages allocated when backing a VMA. In the majority
621 * cases this will be same size as used by the page table entries.
623 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
625 struct hstate
*hstate
;
627 if (!is_vm_hugetlb_page(vma
))
630 hstate
= hstate_vma(vma
);
632 return 1UL << huge_page_shift(hstate
);
634 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
637 * Return the page size being used by the MMU to back a VMA. In the majority
638 * of cases, the page size used by the kernel matches the MMU size. On
639 * architectures where it differs, an architecture-specific version of this
640 * function is required.
642 #ifndef vma_mmu_pagesize
643 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
645 return vma_kernel_pagesize(vma
);
650 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
651 * bits of the reservation map pointer, which are always clear due to
654 #define HPAGE_RESV_OWNER (1UL << 0)
655 #define HPAGE_RESV_UNMAPPED (1UL << 1)
656 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
659 * These helpers are used to track how many pages are reserved for
660 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
661 * is guaranteed to have their future faults succeed.
663 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
664 * the reserve counters are updated with the hugetlb_lock held. It is safe
665 * to reset the VMA at fork() time as it is not in use yet and there is no
666 * chance of the global counters getting corrupted as a result of the values.
668 * The private mapping reservation is represented in a subtly different
669 * manner to a shared mapping. A shared mapping has a region map associated
670 * with the underlying file, this region map represents the backing file
671 * pages which have ever had a reservation assigned which this persists even
672 * after the page is instantiated. A private mapping has a region map
673 * associated with the original mmap which is attached to all VMAs which
674 * reference it, this region map represents those offsets which have consumed
675 * reservation ie. where pages have been instantiated.
677 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
679 return (unsigned long)vma
->vm_private_data
;
682 static void set_vma_private_data(struct vm_area_struct
*vma
,
685 vma
->vm_private_data
= (void *)value
;
688 struct resv_map
*resv_map_alloc(void)
690 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
691 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
693 if (!resv_map
|| !rg
) {
699 kref_init(&resv_map
->refs
);
700 spin_lock_init(&resv_map
->lock
);
701 INIT_LIST_HEAD(&resv_map
->regions
);
703 resv_map
->adds_in_progress
= 0;
705 INIT_LIST_HEAD(&resv_map
->region_cache
);
706 list_add(&rg
->link
, &resv_map
->region_cache
);
707 resv_map
->region_cache_count
= 1;
712 void resv_map_release(struct kref
*ref
)
714 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
715 struct list_head
*head
= &resv_map
->region_cache
;
716 struct file_region
*rg
, *trg
;
718 /* Clear out any active regions before we release the map. */
719 region_del(resv_map
, 0, LONG_MAX
);
721 /* ... and any entries left in the cache */
722 list_for_each_entry_safe(rg
, trg
, head
, link
) {
727 VM_BUG_ON(resv_map
->adds_in_progress
);
732 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
734 return inode
->i_mapping
->private_data
;
737 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
739 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
740 if (vma
->vm_flags
& VM_MAYSHARE
) {
741 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
742 struct inode
*inode
= mapping
->host
;
744 return inode_resv_map(inode
);
747 return (struct resv_map
*)(get_vma_private_data(vma
) &
752 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
754 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
755 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
757 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
758 HPAGE_RESV_MASK
) | (unsigned long)map
);
761 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
763 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
764 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
766 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
769 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
771 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
773 return (get_vma_private_data(vma
) & flag
) != 0;
776 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
777 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
779 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
780 if (!(vma
->vm_flags
& VM_MAYSHARE
))
781 vma
->vm_private_data
= (void *)0;
784 /* Returns true if the VMA has associated reserve pages */
785 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
787 if (vma
->vm_flags
& VM_NORESERVE
) {
789 * This address is already reserved by other process(chg == 0),
790 * so, we should decrement reserved count. Without decrementing,
791 * reserve count remains after releasing inode, because this
792 * allocated page will go into page cache and is regarded as
793 * coming from reserved pool in releasing step. Currently, we
794 * don't have any other solution to deal with this situation
795 * properly, so add work-around here.
797 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
803 /* Shared mappings always use reserves */
804 if (vma
->vm_flags
& VM_MAYSHARE
) {
806 * We know VM_NORESERVE is not set. Therefore, there SHOULD
807 * be a region map for all pages. The only situation where
808 * there is no region map is if a hole was punched via
809 * fallocate. In this case, there really are no reverves to
810 * use. This situation is indicated if chg != 0.
819 * Only the process that called mmap() has reserves for
822 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
828 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
830 int nid
= page_to_nid(page
);
831 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
832 h
->free_huge_pages
++;
833 h
->free_huge_pages_node
[nid
]++;
836 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
840 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
841 if (!is_migrate_isolate_page(page
))
844 * if 'non-isolated free hugepage' not found on the list,
845 * the allocation fails.
847 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
849 list_move(&page
->lru
, &h
->hugepage_activelist
);
850 set_page_refcounted(page
);
851 h
->free_huge_pages
--;
852 h
->free_huge_pages_node
[nid
]--;
856 /* Movability of hugepages depends on migration support. */
857 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
859 if (hugepages_treat_as_movable
|| hugepage_migration_supported(h
))
860 return GFP_HIGHUSER_MOVABLE
;
865 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
866 struct vm_area_struct
*vma
,
867 unsigned long address
, int avoid_reserve
,
870 struct page
*page
= NULL
;
871 struct mempolicy
*mpol
;
872 nodemask_t
*nodemask
;
873 struct zonelist
*zonelist
;
876 unsigned int cpuset_mems_cookie
;
879 * A child process with MAP_PRIVATE mappings created by their parent
880 * have no page reserves. This check ensures that reservations are
881 * not "stolen". The child may still get SIGKILLed
883 if (!vma_has_reserves(vma
, chg
) &&
884 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
887 /* If reserves cannot be used, ensure enough pages are in the pool */
888 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
892 cpuset_mems_cookie
= read_mems_allowed_begin();
893 zonelist
= huge_zonelist(vma
, address
,
894 htlb_alloc_mask(h
), &mpol
, &nodemask
);
896 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
897 MAX_NR_ZONES
- 1, nodemask
) {
898 if (cpuset_zone_allowed(zone
, htlb_alloc_mask(h
))) {
899 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
903 if (!vma_has_reserves(vma
, chg
))
906 SetPagePrivate(page
);
907 h
->resv_huge_pages
--;
914 if (unlikely(!page
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
923 * common helper functions for hstate_next_node_to_{alloc|free}.
924 * We may have allocated or freed a huge page based on a different
925 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
926 * be outside of *nodes_allowed. Ensure that we use an allowed
927 * node for alloc or free.
929 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
931 nid
= next_node(nid
, *nodes_allowed
);
932 if (nid
== MAX_NUMNODES
)
933 nid
= first_node(*nodes_allowed
);
934 VM_BUG_ON(nid
>= MAX_NUMNODES
);
939 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
941 if (!node_isset(nid
, *nodes_allowed
))
942 nid
= next_node_allowed(nid
, nodes_allowed
);
947 * returns the previously saved node ["this node"] from which to
948 * allocate a persistent huge page for the pool and advance the
949 * next node from which to allocate, handling wrap at end of node
952 static int hstate_next_node_to_alloc(struct hstate
*h
,
953 nodemask_t
*nodes_allowed
)
957 VM_BUG_ON(!nodes_allowed
);
959 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
960 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
966 * helper for free_pool_huge_page() - return the previously saved
967 * node ["this node"] from which to free a huge page. Advance the
968 * next node id whether or not we find a free huge page to free so
969 * that the next attempt to free addresses the next node.
971 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
975 VM_BUG_ON(!nodes_allowed
);
977 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
978 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
983 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
984 for (nr_nodes = nodes_weight(*mask); \
986 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
989 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
990 for (nr_nodes = nodes_weight(*mask); \
992 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
995 #if defined(CONFIG_CMA) && defined(CONFIG_X86_64)
996 static void destroy_compound_gigantic_page(struct page
*page
,
1000 int nr_pages
= 1 << order
;
1001 struct page
*p
= page
+ 1;
1003 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1005 set_page_refcounted(p
);
1006 p
->first_page
= NULL
;
1009 set_compound_order(page
, 0);
1010 __ClearPageHead(page
);
1013 static void free_gigantic_page(struct page
*page
, unsigned order
)
1015 free_contig_range(page_to_pfn(page
), 1 << order
);
1018 static int __alloc_gigantic_page(unsigned long start_pfn
,
1019 unsigned long nr_pages
)
1021 unsigned long end_pfn
= start_pfn
+ nr_pages
;
1022 return alloc_contig_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
);
1025 static bool pfn_range_valid_gigantic(unsigned long start_pfn
,
1026 unsigned long nr_pages
)
1028 unsigned long i
, end_pfn
= start_pfn
+ nr_pages
;
1031 for (i
= start_pfn
; i
< end_pfn
; i
++) {
1035 page
= pfn_to_page(i
);
1037 if (PageReserved(page
))
1040 if (page_count(page
) > 0)
1050 static bool zone_spans_last_pfn(const struct zone
*zone
,
1051 unsigned long start_pfn
, unsigned long nr_pages
)
1053 unsigned long last_pfn
= start_pfn
+ nr_pages
- 1;
1054 return zone_spans_pfn(zone
, last_pfn
);
1057 static struct page
*alloc_gigantic_page(int nid
, unsigned order
)
1059 unsigned long nr_pages
= 1 << order
;
1060 unsigned long ret
, pfn
, flags
;
1063 z
= NODE_DATA(nid
)->node_zones
;
1064 for (; z
- NODE_DATA(nid
)->node_zones
< MAX_NR_ZONES
; z
++) {
1065 spin_lock_irqsave(&z
->lock
, flags
);
1067 pfn
= ALIGN(z
->zone_start_pfn
, nr_pages
);
1068 while (zone_spans_last_pfn(z
, pfn
, nr_pages
)) {
1069 if (pfn_range_valid_gigantic(pfn
, nr_pages
)) {
1071 * We release the zone lock here because
1072 * alloc_contig_range() will also lock the zone
1073 * at some point. If there's an allocation
1074 * spinning on this lock, it may win the race
1075 * and cause alloc_contig_range() to fail...
1077 spin_unlock_irqrestore(&z
->lock
, flags
);
1078 ret
= __alloc_gigantic_page(pfn
, nr_pages
);
1080 return pfn_to_page(pfn
);
1081 spin_lock_irqsave(&z
->lock
, flags
);
1086 spin_unlock_irqrestore(&z
->lock
, flags
);
1092 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1093 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
);
1095 static struct page
*alloc_fresh_gigantic_page_node(struct hstate
*h
, int nid
)
1099 page
= alloc_gigantic_page(nid
, huge_page_order(h
));
1101 prep_compound_gigantic_page(page
, huge_page_order(h
));
1102 prep_new_huge_page(h
, page
, nid
);
1108 static int alloc_fresh_gigantic_page(struct hstate
*h
,
1109 nodemask_t
*nodes_allowed
)
1111 struct page
*page
= NULL
;
1114 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1115 page
= alloc_fresh_gigantic_page_node(h
, node
);
1123 static inline bool gigantic_page_supported(void) { return true; }
1125 static inline bool gigantic_page_supported(void) { return false; }
1126 static inline void free_gigantic_page(struct page
*page
, unsigned order
) { }
1127 static inline void destroy_compound_gigantic_page(struct page
*page
,
1128 unsigned long order
) { }
1129 static inline int alloc_fresh_gigantic_page(struct hstate
*h
,
1130 nodemask_t
*nodes_allowed
) { return 0; }
1133 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1137 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
1141 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1142 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1143 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1144 1 << PG_referenced
| 1 << PG_dirty
|
1145 1 << PG_active
| 1 << PG_private
|
1148 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1149 set_compound_page_dtor(page
, NULL
);
1150 set_page_refcounted(page
);
1151 if (hstate_is_gigantic(h
)) {
1152 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1153 free_gigantic_page(page
, huge_page_order(h
));
1155 __free_pages(page
, huge_page_order(h
));
1159 struct hstate
*size_to_hstate(unsigned long size
)
1163 for_each_hstate(h
) {
1164 if (huge_page_size(h
) == size
)
1171 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1172 * to hstate->hugepage_activelist.)
1174 * This function can be called for tail pages, but never returns true for them.
1176 bool page_huge_active(struct page
*page
)
1178 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1179 return PageHead(page
) && PagePrivate(&page
[1]);
1182 /* never called for tail page */
1183 static void set_page_huge_active(struct page
*page
)
1185 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1186 SetPagePrivate(&page
[1]);
1189 static void clear_page_huge_active(struct page
*page
)
1191 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1192 ClearPagePrivate(&page
[1]);
1195 void free_huge_page(struct page
*page
)
1198 * Can't pass hstate in here because it is called from the
1199 * compound page destructor.
1201 struct hstate
*h
= page_hstate(page
);
1202 int nid
= page_to_nid(page
);
1203 struct hugepage_subpool
*spool
=
1204 (struct hugepage_subpool
*)page_private(page
);
1205 bool restore_reserve
;
1207 set_page_private(page
, 0);
1208 page
->mapping
= NULL
;
1209 BUG_ON(page_count(page
));
1210 BUG_ON(page_mapcount(page
));
1211 restore_reserve
= PagePrivate(page
);
1212 ClearPagePrivate(page
);
1215 * A return code of zero implies that the subpool will be under its
1216 * minimum size if the reservation is not restored after page is free.
1217 * Therefore, force restore_reserve operation.
1219 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1220 restore_reserve
= true;
1222 spin_lock(&hugetlb_lock
);
1223 clear_page_huge_active(page
);
1224 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1225 pages_per_huge_page(h
), page
);
1226 if (restore_reserve
)
1227 h
->resv_huge_pages
++;
1229 if (h
->surplus_huge_pages_node
[nid
]) {
1230 /* remove the page from active list */
1231 list_del(&page
->lru
);
1232 update_and_free_page(h
, page
);
1233 h
->surplus_huge_pages
--;
1234 h
->surplus_huge_pages_node
[nid
]--;
1236 arch_clear_hugepage_flags(page
);
1237 enqueue_huge_page(h
, page
);
1239 spin_unlock(&hugetlb_lock
);
1242 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1244 INIT_LIST_HEAD(&page
->lru
);
1245 set_compound_page_dtor(page
, free_huge_page
);
1246 spin_lock(&hugetlb_lock
);
1247 set_hugetlb_cgroup(page
, NULL
);
1249 h
->nr_huge_pages_node
[nid
]++;
1250 spin_unlock(&hugetlb_lock
);
1251 put_page(page
); /* free it into the hugepage allocator */
1254 static void prep_compound_gigantic_page(struct page
*page
, unsigned long order
)
1257 int nr_pages
= 1 << order
;
1258 struct page
*p
= page
+ 1;
1260 /* we rely on prep_new_huge_page to set the destructor */
1261 set_compound_order(page
, order
);
1262 __SetPageHead(page
);
1263 __ClearPageReserved(page
);
1264 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1266 * For gigantic hugepages allocated through bootmem at
1267 * boot, it's safer to be consistent with the not-gigantic
1268 * hugepages and clear the PG_reserved bit from all tail pages
1269 * too. Otherwse drivers using get_user_pages() to access tail
1270 * pages may get the reference counting wrong if they see
1271 * PG_reserved set on a tail page (despite the head page not
1272 * having PG_reserved set). Enforcing this consistency between
1273 * head and tail pages allows drivers to optimize away a check
1274 * on the head page when they need know if put_page() is needed
1275 * after get_user_pages().
1277 __ClearPageReserved(p
);
1278 set_page_count(p
, 0);
1279 p
->first_page
= page
;
1280 /* Make sure p->first_page is always valid for PageTail() */
1287 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1288 * transparent huge pages. See the PageTransHuge() documentation for more
1291 int PageHuge(struct page
*page
)
1293 if (!PageCompound(page
))
1296 page
= compound_head(page
);
1297 return get_compound_page_dtor(page
) == free_huge_page
;
1299 EXPORT_SYMBOL_GPL(PageHuge
);
1302 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1303 * normal or transparent huge pages.
1305 int PageHeadHuge(struct page
*page_head
)
1307 if (!PageHead(page_head
))
1310 return get_compound_page_dtor(page_head
) == free_huge_page
;
1313 pgoff_t
__basepage_index(struct page
*page
)
1315 struct page
*page_head
= compound_head(page
);
1316 pgoff_t index
= page_index(page_head
);
1317 unsigned long compound_idx
;
1319 if (!PageHuge(page_head
))
1320 return page_index(page
);
1322 if (compound_order(page_head
) >= MAX_ORDER
)
1323 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1325 compound_idx
= page
- page_head
;
1327 return (index
<< compound_order(page_head
)) + compound_idx
;
1330 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
1334 page
= __alloc_pages_node(nid
,
1335 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
1336 __GFP_REPEAT
|__GFP_NOWARN
,
1337 huge_page_order(h
));
1339 prep_new_huge_page(h
, page
, nid
);
1345 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1351 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1352 page
= alloc_fresh_huge_page_node(h
, node
);
1360 count_vm_event(HTLB_BUDDY_PGALLOC
);
1362 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1368 * Free huge page from pool from next node to free.
1369 * Attempt to keep persistent huge pages more or less
1370 * balanced over allowed nodes.
1371 * Called with hugetlb_lock locked.
1373 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1379 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1381 * If we're returning unused surplus pages, only examine
1382 * nodes with surplus pages.
1384 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1385 !list_empty(&h
->hugepage_freelists
[node
])) {
1387 list_entry(h
->hugepage_freelists
[node
].next
,
1389 list_del(&page
->lru
);
1390 h
->free_huge_pages
--;
1391 h
->free_huge_pages_node
[node
]--;
1393 h
->surplus_huge_pages
--;
1394 h
->surplus_huge_pages_node
[node
]--;
1396 update_and_free_page(h
, page
);
1406 * Dissolve a given free hugepage into free buddy pages. This function does
1407 * nothing for in-use (including surplus) hugepages.
1409 static void dissolve_free_huge_page(struct page
*page
)
1411 spin_lock(&hugetlb_lock
);
1412 if (PageHuge(page
) && !page_count(page
)) {
1413 struct hstate
*h
= page_hstate(page
);
1414 int nid
= page_to_nid(page
);
1415 list_del(&page
->lru
);
1416 h
->free_huge_pages
--;
1417 h
->free_huge_pages_node
[nid
]--;
1418 update_and_free_page(h
, page
);
1420 spin_unlock(&hugetlb_lock
);
1424 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1425 * make specified memory blocks removable from the system.
1426 * Note that start_pfn should aligned with (minimum) hugepage size.
1428 void dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1432 if (!hugepages_supported())
1435 VM_BUG_ON(!IS_ALIGNED(start_pfn
, 1 << minimum_order
));
1436 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
)
1437 dissolve_free_huge_page(pfn_to_page(pfn
));
1441 * There are 3 ways this can get called:
1442 * 1. With vma+addr: we use the VMA's memory policy
1443 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1444 * page from any node, and let the buddy allocator itself figure
1446 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1447 * strictly from 'nid'
1449 static struct page
*__hugetlb_alloc_buddy_huge_page(struct hstate
*h
,
1450 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1452 int order
= huge_page_order(h
);
1453 gfp_t gfp
= htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_REPEAT
|__GFP_NOWARN
;
1454 unsigned int cpuset_mems_cookie
;
1457 * We need a VMA to get a memory policy. If we do not
1458 * have one, we use the 'nid' argument.
1460 * The mempolicy stuff below has some non-inlined bits
1461 * and calls ->vm_ops. That makes it hard to optimize at
1462 * compile-time, even when NUMA is off and it does
1463 * nothing. This helps the compiler optimize it out.
1465 if (!IS_ENABLED(CONFIG_NUMA
) || !vma
) {
1467 * If a specific node is requested, make sure to
1468 * get memory from there, but only when a node
1469 * is explicitly specified.
1471 if (nid
!= NUMA_NO_NODE
)
1472 gfp
|= __GFP_THISNODE
;
1474 * Make sure to call something that can handle
1477 return alloc_pages_node(nid
, gfp
, order
);
1481 * OK, so we have a VMA. Fetch the mempolicy and try to
1482 * allocate a huge page with it. We will only reach this
1483 * when CONFIG_NUMA=y.
1487 struct mempolicy
*mpol
;
1488 struct zonelist
*zl
;
1489 nodemask_t
*nodemask
;
1491 cpuset_mems_cookie
= read_mems_allowed_begin();
1492 zl
= huge_zonelist(vma
, addr
, gfp
, &mpol
, &nodemask
);
1493 mpol_cond_put(mpol
);
1494 page
= __alloc_pages_nodemask(gfp
, order
, zl
, nodemask
);
1497 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1503 * There are two ways to allocate a huge page:
1504 * 1. When you have a VMA and an address (like a fault)
1505 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1507 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1508 * this case which signifies that the allocation should be done with
1509 * respect for the VMA's memory policy.
1511 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1512 * implies that memory policies will not be taken in to account.
1514 static struct page
*__alloc_buddy_huge_page(struct hstate
*h
,
1515 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1520 if (hstate_is_gigantic(h
))
1524 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1525 * This makes sure the caller is picking _one_ of the modes with which
1526 * we can call this function, not both.
1528 if (vma
|| (addr
!= -1)) {
1529 VM_WARN_ON_ONCE(addr
== -1);
1530 VM_WARN_ON_ONCE(nid
!= NUMA_NO_NODE
);
1533 * Assume we will successfully allocate the surplus page to
1534 * prevent racing processes from causing the surplus to exceed
1537 * This however introduces a different race, where a process B
1538 * tries to grow the static hugepage pool while alloc_pages() is
1539 * called by process A. B will only examine the per-node
1540 * counters in determining if surplus huge pages can be
1541 * converted to normal huge pages in adjust_pool_surplus(). A
1542 * won't be able to increment the per-node counter, until the
1543 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1544 * no more huge pages can be converted from surplus to normal
1545 * state (and doesn't try to convert again). Thus, we have a
1546 * case where a surplus huge page exists, the pool is grown, and
1547 * the surplus huge page still exists after, even though it
1548 * should just have been converted to a normal huge page. This
1549 * does not leak memory, though, as the hugepage will be freed
1550 * once it is out of use. It also does not allow the counters to
1551 * go out of whack in adjust_pool_surplus() as we don't modify
1552 * the node values until we've gotten the hugepage and only the
1553 * per-node value is checked there.
1555 spin_lock(&hugetlb_lock
);
1556 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1557 spin_unlock(&hugetlb_lock
);
1561 h
->surplus_huge_pages
++;
1563 spin_unlock(&hugetlb_lock
);
1565 page
= __hugetlb_alloc_buddy_huge_page(h
, vma
, addr
, nid
);
1567 spin_lock(&hugetlb_lock
);
1569 INIT_LIST_HEAD(&page
->lru
);
1570 r_nid
= page_to_nid(page
);
1571 set_compound_page_dtor(page
, free_huge_page
);
1572 set_hugetlb_cgroup(page
, NULL
);
1574 * We incremented the global counters already
1576 h
->nr_huge_pages_node
[r_nid
]++;
1577 h
->surplus_huge_pages_node
[r_nid
]++;
1578 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1581 h
->surplus_huge_pages
--;
1582 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1584 spin_unlock(&hugetlb_lock
);
1590 * Allocate a huge page from 'nid'. Note, 'nid' may be
1591 * NUMA_NO_NODE, which means that it may be allocated
1595 struct page
*__alloc_buddy_huge_page_no_mpol(struct hstate
*h
, int nid
)
1597 unsigned long addr
= -1;
1599 return __alloc_buddy_huge_page(h
, NULL
, addr
, nid
);
1603 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1606 struct page
*__alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1607 struct vm_area_struct
*vma
, unsigned long addr
)
1609 return __alloc_buddy_huge_page(h
, vma
, addr
, NUMA_NO_NODE
);
1613 * This allocation function is useful in the context where vma is irrelevant.
1614 * E.g. soft-offlining uses this function because it only cares physical
1615 * address of error page.
1617 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1619 struct page
*page
= NULL
;
1621 spin_lock(&hugetlb_lock
);
1622 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1623 page
= dequeue_huge_page_node(h
, nid
);
1624 spin_unlock(&hugetlb_lock
);
1627 page
= __alloc_buddy_huge_page_no_mpol(h
, nid
);
1633 * Increase the hugetlb pool such that it can accommodate a reservation
1636 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1638 struct list_head surplus_list
;
1639 struct page
*page
, *tmp
;
1641 int needed
, allocated
;
1642 bool alloc_ok
= true;
1644 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1646 h
->resv_huge_pages
+= delta
;
1651 INIT_LIST_HEAD(&surplus_list
);
1655 spin_unlock(&hugetlb_lock
);
1656 for (i
= 0; i
< needed
; i
++) {
1657 page
= __alloc_buddy_huge_page_no_mpol(h
, NUMA_NO_NODE
);
1662 list_add(&page
->lru
, &surplus_list
);
1667 * After retaking hugetlb_lock, we need to recalculate 'needed'
1668 * because either resv_huge_pages or free_huge_pages may have changed.
1670 spin_lock(&hugetlb_lock
);
1671 needed
= (h
->resv_huge_pages
+ delta
) -
1672 (h
->free_huge_pages
+ allocated
);
1677 * We were not able to allocate enough pages to
1678 * satisfy the entire reservation so we free what
1679 * we've allocated so far.
1684 * The surplus_list now contains _at_least_ the number of extra pages
1685 * needed to accommodate the reservation. Add the appropriate number
1686 * of pages to the hugetlb pool and free the extras back to the buddy
1687 * allocator. Commit the entire reservation here to prevent another
1688 * process from stealing the pages as they are added to the pool but
1689 * before they are reserved.
1691 needed
+= allocated
;
1692 h
->resv_huge_pages
+= delta
;
1695 /* Free the needed pages to the hugetlb pool */
1696 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1700 * This page is now managed by the hugetlb allocator and has
1701 * no users -- drop the buddy allocator's reference.
1703 put_page_testzero(page
);
1704 VM_BUG_ON_PAGE(page_count(page
), page
);
1705 enqueue_huge_page(h
, page
);
1708 spin_unlock(&hugetlb_lock
);
1710 /* Free unnecessary surplus pages to the buddy allocator */
1711 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1713 spin_lock(&hugetlb_lock
);
1719 * When releasing a hugetlb pool reservation, any surplus pages that were
1720 * allocated to satisfy the reservation must be explicitly freed if they were
1722 * Called with hugetlb_lock held.
1724 static void return_unused_surplus_pages(struct hstate
*h
,
1725 unsigned long unused_resv_pages
)
1727 unsigned long nr_pages
;
1729 /* Uncommit the reservation */
1730 h
->resv_huge_pages
-= unused_resv_pages
;
1732 /* Cannot return gigantic pages currently */
1733 if (hstate_is_gigantic(h
))
1736 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1739 * We want to release as many surplus pages as possible, spread
1740 * evenly across all nodes with memory. Iterate across these nodes
1741 * until we can no longer free unreserved surplus pages. This occurs
1742 * when the nodes with surplus pages have no free pages.
1743 * free_pool_huge_page() will balance the the freed pages across the
1744 * on-line nodes with memory and will handle the hstate accounting.
1746 while (nr_pages
--) {
1747 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1749 cond_resched_lock(&hugetlb_lock
);
1755 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1756 * are used by the huge page allocation routines to manage reservations.
1758 * vma_needs_reservation is called to determine if the huge page at addr
1759 * within the vma has an associated reservation. If a reservation is
1760 * needed, the value 1 is returned. The caller is then responsible for
1761 * managing the global reservation and subpool usage counts. After
1762 * the huge page has been allocated, vma_commit_reservation is called
1763 * to add the page to the reservation map. If the page allocation fails,
1764 * the reservation must be ended instead of committed. vma_end_reservation
1765 * is called in such cases.
1767 * In the normal case, vma_commit_reservation returns the same value
1768 * as the preceding vma_needs_reservation call. The only time this
1769 * is not the case is if a reserve map was changed between calls. It
1770 * is the responsibility of the caller to notice the difference and
1771 * take appropriate action.
1773 enum vma_resv_mode
{
1778 static long __vma_reservation_common(struct hstate
*h
,
1779 struct vm_area_struct
*vma
, unsigned long addr
,
1780 enum vma_resv_mode mode
)
1782 struct resv_map
*resv
;
1786 resv
= vma_resv_map(vma
);
1790 idx
= vma_hugecache_offset(h
, vma
, addr
);
1792 case VMA_NEEDS_RESV
:
1793 ret
= region_chg(resv
, idx
, idx
+ 1);
1795 case VMA_COMMIT_RESV
:
1796 ret
= region_add(resv
, idx
, idx
+ 1);
1799 region_abort(resv
, idx
, idx
+ 1);
1806 if (vma
->vm_flags
& VM_MAYSHARE
)
1809 return ret
< 0 ? ret
: 0;
1812 static long vma_needs_reservation(struct hstate
*h
,
1813 struct vm_area_struct
*vma
, unsigned long addr
)
1815 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
1818 static long vma_commit_reservation(struct hstate
*h
,
1819 struct vm_area_struct
*vma
, unsigned long addr
)
1821 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
1824 static void vma_end_reservation(struct hstate
*h
,
1825 struct vm_area_struct
*vma
, unsigned long addr
)
1827 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
1830 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1831 unsigned long addr
, int avoid_reserve
)
1833 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1834 struct hstate
*h
= hstate_vma(vma
);
1836 long map_chg
, map_commit
;
1839 struct hugetlb_cgroup
*h_cg
;
1841 idx
= hstate_index(h
);
1843 * Examine the region/reserve map to determine if the process
1844 * has a reservation for the page to be allocated. A return
1845 * code of zero indicates a reservation exists (no change).
1847 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
1849 return ERR_PTR(-ENOMEM
);
1852 * Processes that did not create the mapping will have no
1853 * reserves as indicated by the region/reserve map. Check
1854 * that the allocation will not exceed the subpool limit.
1855 * Allocations for MAP_NORESERVE mappings also need to be
1856 * checked against any subpool limit.
1858 if (map_chg
|| avoid_reserve
) {
1859 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
1861 vma_end_reservation(h
, vma
, addr
);
1862 return ERR_PTR(-ENOSPC
);
1866 * Even though there was no reservation in the region/reserve
1867 * map, there could be reservations associated with the
1868 * subpool that can be used. This would be indicated if the
1869 * return value of hugepage_subpool_get_pages() is zero.
1870 * However, if avoid_reserve is specified we still avoid even
1871 * the subpool reservations.
1877 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1879 goto out_subpool_put
;
1881 spin_lock(&hugetlb_lock
);
1883 * glb_chg is passed to indicate whether or not a page must be taken
1884 * from the global free pool (global change). gbl_chg == 0 indicates
1885 * a reservation exists for the allocation.
1887 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
1889 spin_unlock(&hugetlb_lock
);
1890 page
= __alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
1892 goto out_uncharge_cgroup
;
1894 spin_lock(&hugetlb_lock
);
1895 list_move(&page
->lru
, &h
->hugepage_activelist
);
1898 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1899 spin_unlock(&hugetlb_lock
);
1901 set_page_private(page
, (unsigned long)spool
);
1903 map_commit
= vma_commit_reservation(h
, vma
, addr
);
1904 if (unlikely(map_chg
> map_commit
)) {
1906 * The page was added to the reservation map between
1907 * vma_needs_reservation and vma_commit_reservation.
1908 * This indicates a race with hugetlb_reserve_pages.
1909 * Adjust for the subpool count incremented above AND
1910 * in hugetlb_reserve_pages for the same page. Also,
1911 * the reservation count added in hugetlb_reserve_pages
1912 * no longer applies.
1916 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
1917 hugetlb_acct_memory(h
, -rsv_adjust
);
1921 out_uncharge_cgroup
:
1922 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
1924 if (map_chg
|| avoid_reserve
)
1925 hugepage_subpool_put_pages(spool
, 1);
1926 vma_end_reservation(h
, vma
, addr
);
1927 return ERR_PTR(-ENOSPC
);
1931 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1932 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1933 * where no ERR_VALUE is expected to be returned.
1935 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
1936 unsigned long addr
, int avoid_reserve
)
1938 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
1944 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1946 struct huge_bootmem_page
*m
;
1949 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1952 addr
= memblock_virt_alloc_try_nid_nopanic(
1953 huge_page_size(h
), huge_page_size(h
),
1954 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
1957 * Use the beginning of the huge page to store the
1958 * huge_bootmem_page struct (until gather_bootmem
1959 * puts them into the mem_map).
1968 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
1969 /* Put them into a private list first because mem_map is not up yet */
1970 list_add(&m
->list
, &huge_boot_pages
);
1975 static void __init
prep_compound_huge_page(struct page
*page
, int order
)
1977 if (unlikely(order
> (MAX_ORDER
- 1)))
1978 prep_compound_gigantic_page(page
, order
);
1980 prep_compound_page(page
, order
);
1983 /* Put bootmem huge pages into the standard lists after mem_map is up */
1984 static void __init
gather_bootmem_prealloc(void)
1986 struct huge_bootmem_page
*m
;
1988 list_for_each_entry(m
, &huge_boot_pages
, list
) {
1989 struct hstate
*h
= m
->hstate
;
1992 #ifdef CONFIG_HIGHMEM
1993 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
1994 memblock_free_late(__pa(m
),
1995 sizeof(struct huge_bootmem_page
));
1997 page
= virt_to_page(m
);
1999 WARN_ON(page_count(page
) != 1);
2000 prep_compound_huge_page(page
, h
->order
);
2001 WARN_ON(PageReserved(page
));
2002 prep_new_huge_page(h
, page
, page_to_nid(page
));
2004 * If we had gigantic hugepages allocated at boot time, we need
2005 * to restore the 'stolen' pages to totalram_pages in order to
2006 * fix confusing memory reports from free(1) and another
2007 * side-effects, like CommitLimit going negative.
2009 if (hstate_is_gigantic(h
))
2010 adjust_managed_page_count(page
, 1 << h
->order
);
2014 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2018 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2019 if (hstate_is_gigantic(h
)) {
2020 if (!alloc_bootmem_huge_page(h
))
2022 } else if (!alloc_fresh_huge_page(h
,
2023 &node_states
[N_MEMORY
]))
2026 h
->max_huge_pages
= i
;
2029 static void __init
hugetlb_init_hstates(void)
2033 for_each_hstate(h
) {
2034 if (minimum_order
> huge_page_order(h
))
2035 minimum_order
= huge_page_order(h
);
2037 /* oversize hugepages were init'ed in early boot */
2038 if (!hstate_is_gigantic(h
))
2039 hugetlb_hstate_alloc_pages(h
);
2041 VM_BUG_ON(minimum_order
== UINT_MAX
);
2044 static char * __init
memfmt(char *buf
, unsigned long n
)
2046 if (n
>= (1UL << 30))
2047 sprintf(buf
, "%lu GB", n
>> 30);
2048 else if (n
>= (1UL << 20))
2049 sprintf(buf
, "%lu MB", n
>> 20);
2051 sprintf(buf
, "%lu KB", n
>> 10);
2055 static void __init
report_hugepages(void)
2059 for_each_hstate(h
) {
2061 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2062 memfmt(buf
, huge_page_size(h
)),
2063 h
->free_huge_pages
);
2067 #ifdef CONFIG_HIGHMEM
2068 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2069 nodemask_t
*nodes_allowed
)
2073 if (hstate_is_gigantic(h
))
2076 for_each_node_mask(i
, *nodes_allowed
) {
2077 struct page
*page
, *next
;
2078 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2079 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2080 if (count
>= h
->nr_huge_pages
)
2082 if (PageHighMem(page
))
2084 list_del(&page
->lru
);
2085 update_and_free_page(h
, page
);
2086 h
->free_huge_pages
--;
2087 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2092 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2093 nodemask_t
*nodes_allowed
)
2099 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2100 * balanced by operating on them in a round-robin fashion.
2101 * Returns 1 if an adjustment was made.
2103 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2108 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2111 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2112 if (h
->surplus_huge_pages_node
[node
])
2116 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2117 if (h
->surplus_huge_pages_node
[node
] <
2118 h
->nr_huge_pages_node
[node
])
2125 h
->surplus_huge_pages
+= delta
;
2126 h
->surplus_huge_pages_node
[node
] += delta
;
2130 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2131 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
2132 nodemask_t
*nodes_allowed
)
2134 unsigned long min_count
, ret
;
2136 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
2137 return h
->max_huge_pages
;
2140 * Increase the pool size
2141 * First take pages out of surplus state. Then make up the
2142 * remaining difference by allocating fresh huge pages.
2144 * We might race with alloc_buddy_huge_page() here and be unable
2145 * to convert a surplus huge page to a normal huge page. That is
2146 * not critical, though, it just means the overall size of the
2147 * pool might be one hugepage larger than it needs to be, but
2148 * within all the constraints specified by the sysctls.
2150 spin_lock(&hugetlb_lock
);
2151 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2152 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2156 while (count
> persistent_huge_pages(h
)) {
2158 * If this allocation races such that we no longer need the
2159 * page, free_huge_page will handle it by freeing the page
2160 * and reducing the surplus.
2162 spin_unlock(&hugetlb_lock
);
2163 if (hstate_is_gigantic(h
))
2164 ret
= alloc_fresh_gigantic_page(h
, nodes_allowed
);
2166 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
2167 spin_lock(&hugetlb_lock
);
2171 /* Bail for signals. Probably ctrl-c from user */
2172 if (signal_pending(current
))
2177 * Decrease the pool size
2178 * First return free pages to the buddy allocator (being careful
2179 * to keep enough around to satisfy reservations). Then place
2180 * pages into surplus state as needed so the pool will shrink
2181 * to the desired size as pages become free.
2183 * By placing pages into the surplus state independent of the
2184 * overcommit value, we are allowing the surplus pool size to
2185 * exceed overcommit. There are few sane options here. Since
2186 * alloc_buddy_huge_page() is checking the global counter,
2187 * though, we'll note that we're not allowed to exceed surplus
2188 * and won't grow the pool anywhere else. Not until one of the
2189 * sysctls are changed, or the surplus pages go out of use.
2191 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2192 min_count
= max(count
, min_count
);
2193 try_to_free_low(h
, min_count
, nodes_allowed
);
2194 while (min_count
< persistent_huge_pages(h
)) {
2195 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2197 cond_resched_lock(&hugetlb_lock
);
2199 while (count
< persistent_huge_pages(h
)) {
2200 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2204 ret
= persistent_huge_pages(h
);
2205 spin_unlock(&hugetlb_lock
);
2209 #define HSTATE_ATTR_RO(_name) \
2210 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2212 #define HSTATE_ATTR(_name) \
2213 static struct kobj_attribute _name##_attr = \
2214 __ATTR(_name, 0644, _name##_show, _name##_store)
2216 static struct kobject
*hugepages_kobj
;
2217 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2219 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2221 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2225 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2226 if (hstate_kobjs
[i
] == kobj
) {
2228 *nidp
= NUMA_NO_NODE
;
2232 return kobj_to_node_hstate(kobj
, nidp
);
2235 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2236 struct kobj_attribute
*attr
, char *buf
)
2239 unsigned long nr_huge_pages
;
2242 h
= kobj_to_hstate(kobj
, &nid
);
2243 if (nid
== NUMA_NO_NODE
)
2244 nr_huge_pages
= h
->nr_huge_pages
;
2246 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2248 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2251 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2252 struct hstate
*h
, int nid
,
2253 unsigned long count
, size_t len
)
2256 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
2258 if (hstate_is_gigantic(h
) && !gigantic_page_supported()) {
2263 if (nid
== NUMA_NO_NODE
) {
2265 * global hstate attribute
2267 if (!(obey_mempolicy
&&
2268 init_nodemask_of_mempolicy(nodes_allowed
))) {
2269 NODEMASK_FREE(nodes_allowed
);
2270 nodes_allowed
= &node_states
[N_MEMORY
];
2272 } else if (nodes_allowed
) {
2274 * per node hstate attribute: adjust count to global,
2275 * but restrict alloc/free to the specified node.
2277 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2278 init_nodemask_of_node(nodes_allowed
, nid
);
2280 nodes_allowed
= &node_states
[N_MEMORY
];
2282 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
2284 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2285 NODEMASK_FREE(nodes_allowed
);
2289 NODEMASK_FREE(nodes_allowed
);
2293 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2294 struct kobject
*kobj
, const char *buf
,
2298 unsigned long count
;
2302 err
= kstrtoul(buf
, 10, &count
);
2306 h
= kobj_to_hstate(kobj
, &nid
);
2307 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2310 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2311 struct kobj_attribute
*attr
, char *buf
)
2313 return nr_hugepages_show_common(kobj
, attr
, buf
);
2316 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2317 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2319 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2321 HSTATE_ATTR(nr_hugepages
);
2326 * hstate attribute for optionally mempolicy-based constraint on persistent
2327 * huge page alloc/free.
2329 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2330 struct kobj_attribute
*attr
, char *buf
)
2332 return nr_hugepages_show_common(kobj
, attr
, buf
);
2335 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2336 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2338 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2340 HSTATE_ATTR(nr_hugepages_mempolicy
);
2344 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2345 struct kobj_attribute
*attr
, char *buf
)
2347 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2348 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2351 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2352 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2355 unsigned long input
;
2356 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2358 if (hstate_is_gigantic(h
))
2361 err
= kstrtoul(buf
, 10, &input
);
2365 spin_lock(&hugetlb_lock
);
2366 h
->nr_overcommit_huge_pages
= input
;
2367 spin_unlock(&hugetlb_lock
);
2371 HSTATE_ATTR(nr_overcommit_hugepages
);
2373 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2374 struct kobj_attribute
*attr
, char *buf
)
2377 unsigned long free_huge_pages
;
2380 h
= kobj_to_hstate(kobj
, &nid
);
2381 if (nid
== NUMA_NO_NODE
)
2382 free_huge_pages
= h
->free_huge_pages
;
2384 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2386 return sprintf(buf
, "%lu\n", free_huge_pages
);
2388 HSTATE_ATTR_RO(free_hugepages
);
2390 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2391 struct kobj_attribute
*attr
, char *buf
)
2393 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2394 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2396 HSTATE_ATTR_RO(resv_hugepages
);
2398 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2399 struct kobj_attribute
*attr
, char *buf
)
2402 unsigned long surplus_huge_pages
;
2405 h
= kobj_to_hstate(kobj
, &nid
);
2406 if (nid
== NUMA_NO_NODE
)
2407 surplus_huge_pages
= h
->surplus_huge_pages
;
2409 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2411 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2413 HSTATE_ATTR_RO(surplus_hugepages
);
2415 static struct attribute
*hstate_attrs
[] = {
2416 &nr_hugepages_attr
.attr
,
2417 &nr_overcommit_hugepages_attr
.attr
,
2418 &free_hugepages_attr
.attr
,
2419 &resv_hugepages_attr
.attr
,
2420 &surplus_hugepages_attr
.attr
,
2422 &nr_hugepages_mempolicy_attr
.attr
,
2427 static struct attribute_group hstate_attr_group
= {
2428 .attrs
= hstate_attrs
,
2431 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2432 struct kobject
**hstate_kobjs
,
2433 struct attribute_group
*hstate_attr_group
)
2436 int hi
= hstate_index(h
);
2438 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2439 if (!hstate_kobjs
[hi
])
2442 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2444 kobject_put(hstate_kobjs
[hi
]);
2449 static void __init
hugetlb_sysfs_init(void)
2454 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2455 if (!hugepages_kobj
)
2458 for_each_hstate(h
) {
2459 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2460 hstate_kobjs
, &hstate_attr_group
);
2462 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2469 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2470 * with node devices in node_devices[] using a parallel array. The array
2471 * index of a node device or _hstate == node id.
2472 * This is here to avoid any static dependency of the node device driver, in
2473 * the base kernel, on the hugetlb module.
2475 struct node_hstate
{
2476 struct kobject
*hugepages_kobj
;
2477 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2479 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2482 * A subset of global hstate attributes for node devices
2484 static struct attribute
*per_node_hstate_attrs
[] = {
2485 &nr_hugepages_attr
.attr
,
2486 &free_hugepages_attr
.attr
,
2487 &surplus_hugepages_attr
.attr
,
2491 static struct attribute_group per_node_hstate_attr_group
= {
2492 .attrs
= per_node_hstate_attrs
,
2496 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2497 * Returns node id via non-NULL nidp.
2499 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2503 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2504 struct node_hstate
*nhs
= &node_hstates
[nid
];
2506 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2507 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2519 * Unregister hstate attributes from a single node device.
2520 * No-op if no hstate attributes attached.
2522 static void hugetlb_unregister_node(struct node
*node
)
2525 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2527 if (!nhs
->hugepages_kobj
)
2528 return; /* no hstate attributes */
2530 for_each_hstate(h
) {
2531 int idx
= hstate_index(h
);
2532 if (nhs
->hstate_kobjs
[idx
]) {
2533 kobject_put(nhs
->hstate_kobjs
[idx
]);
2534 nhs
->hstate_kobjs
[idx
] = NULL
;
2538 kobject_put(nhs
->hugepages_kobj
);
2539 nhs
->hugepages_kobj
= NULL
;
2543 * hugetlb module exit: unregister hstate attributes from node devices
2546 static void hugetlb_unregister_all_nodes(void)
2551 * disable node device registrations.
2553 register_hugetlbfs_with_node(NULL
, NULL
);
2556 * remove hstate attributes from any nodes that have them.
2558 for (nid
= 0; nid
< nr_node_ids
; nid
++)
2559 hugetlb_unregister_node(node_devices
[nid
]);
2563 * Register hstate attributes for a single node device.
2564 * No-op if attributes already registered.
2566 static void hugetlb_register_node(struct node
*node
)
2569 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2572 if (nhs
->hugepages_kobj
)
2573 return; /* already allocated */
2575 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2577 if (!nhs
->hugepages_kobj
)
2580 for_each_hstate(h
) {
2581 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2583 &per_node_hstate_attr_group
);
2585 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2586 h
->name
, node
->dev
.id
);
2587 hugetlb_unregister_node(node
);
2594 * hugetlb init time: register hstate attributes for all registered node
2595 * devices of nodes that have memory. All on-line nodes should have
2596 * registered their associated device by this time.
2598 static void __init
hugetlb_register_all_nodes(void)
2602 for_each_node_state(nid
, N_MEMORY
) {
2603 struct node
*node
= node_devices
[nid
];
2604 if (node
->dev
.id
== nid
)
2605 hugetlb_register_node(node
);
2609 * Let the node device driver know we're here so it can
2610 * [un]register hstate attributes on node hotplug.
2612 register_hugetlbfs_with_node(hugetlb_register_node
,
2613 hugetlb_unregister_node
);
2615 #else /* !CONFIG_NUMA */
2617 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2625 static void hugetlb_unregister_all_nodes(void) { }
2627 static void hugetlb_register_all_nodes(void) { }
2631 static void __exit
hugetlb_exit(void)
2635 hugetlb_unregister_all_nodes();
2637 for_each_hstate(h
) {
2638 kobject_put(hstate_kobjs
[hstate_index(h
)]);
2641 kobject_put(hugepages_kobj
);
2642 kfree(hugetlb_fault_mutex_table
);
2644 module_exit(hugetlb_exit
);
2646 static int __init
hugetlb_init(void)
2650 if (!hugepages_supported())
2653 if (!size_to_hstate(default_hstate_size
)) {
2654 default_hstate_size
= HPAGE_SIZE
;
2655 if (!size_to_hstate(default_hstate_size
))
2656 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2658 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2659 if (default_hstate_max_huge_pages
)
2660 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2662 hugetlb_init_hstates();
2663 gather_bootmem_prealloc();
2666 hugetlb_sysfs_init();
2667 hugetlb_register_all_nodes();
2668 hugetlb_cgroup_file_init();
2671 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2673 num_fault_mutexes
= 1;
2675 hugetlb_fault_mutex_table
=
2676 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2677 BUG_ON(!hugetlb_fault_mutex_table
);
2679 for (i
= 0; i
< num_fault_mutexes
; i
++)
2680 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2683 module_init(hugetlb_init
);
2685 /* Should be called on processing a hugepagesz=... option */
2686 void __init
hugetlb_add_hstate(unsigned order
)
2691 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2692 pr_warning("hugepagesz= specified twice, ignoring\n");
2695 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2697 h
= &hstates
[hugetlb_max_hstate
++];
2699 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2700 h
->nr_huge_pages
= 0;
2701 h
->free_huge_pages
= 0;
2702 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2703 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2704 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2705 h
->next_nid_to_alloc
= first_node(node_states
[N_MEMORY
]);
2706 h
->next_nid_to_free
= first_node(node_states
[N_MEMORY
]);
2707 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2708 huge_page_size(h
)/1024);
2713 static int __init
hugetlb_nrpages_setup(char *s
)
2716 static unsigned long *last_mhp
;
2719 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2720 * so this hugepages= parameter goes to the "default hstate".
2722 if (!hugetlb_max_hstate
)
2723 mhp
= &default_hstate_max_huge_pages
;
2725 mhp
= &parsed_hstate
->max_huge_pages
;
2727 if (mhp
== last_mhp
) {
2728 pr_warning("hugepages= specified twice without "
2729 "interleaving hugepagesz=, ignoring\n");
2733 if (sscanf(s
, "%lu", mhp
) <= 0)
2737 * Global state is always initialized later in hugetlb_init.
2738 * But we need to allocate >= MAX_ORDER hstates here early to still
2739 * use the bootmem allocator.
2741 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2742 hugetlb_hstate_alloc_pages(parsed_hstate
);
2748 __setup("hugepages=", hugetlb_nrpages_setup
);
2750 static int __init
hugetlb_default_setup(char *s
)
2752 default_hstate_size
= memparse(s
, &s
);
2755 __setup("default_hugepagesz=", hugetlb_default_setup
);
2757 static unsigned int cpuset_mems_nr(unsigned int *array
)
2760 unsigned int nr
= 0;
2762 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2768 #ifdef CONFIG_SYSCTL
2769 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2770 struct ctl_table
*table
, int write
,
2771 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2773 struct hstate
*h
= &default_hstate
;
2774 unsigned long tmp
= h
->max_huge_pages
;
2777 if (!hugepages_supported())
2781 table
->maxlen
= sizeof(unsigned long);
2782 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2787 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
2788 NUMA_NO_NODE
, tmp
, *length
);
2793 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2794 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2797 return hugetlb_sysctl_handler_common(false, table
, write
,
2798 buffer
, length
, ppos
);
2802 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2803 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2805 return hugetlb_sysctl_handler_common(true, table
, write
,
2806 buffer
, length
, ppos
);
2808 #endif /* CONFIG_NUMA */
2810 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2811 void __user
*buffer
,
2812 size_t *length
, loff_t
*ppos
)
2814 struct hstate
*h
= &default_hstate
;
2818 if (!hugepages_supported())
2821 tmp
= h
->nr_overcommit_huge_pages
;
2823 if (write
&& hstate_is_gigantic(h
))
2827 table
->maxlen
= sizeof(unsigned long);
2828 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2833 spin_lock(&hugetlb_lock
);
2834 h
->nr_overcommit_huge_pages
= tmp
;
2835 spin_unlock(&hugetlb_lock
);
2841 #endif /* CONFIG_SYSCTL */
2843 void hugetlb_report_meminfo(struct seq_file
*m
)
2845 struct hstate
*h
= &default_hstate
;
2846 if (!hugepages_supported())
2849 "HugePages_Total: %5lu\n"
2850 "HugePages_Free: %5lu\n"
2851 "HugePages_Rsvd: %5lu\n"
2852 "HugePages_Surp: %5lu\n"
2853 "Hugepagesize: %8lu kB\n",
2857 h
->surplus_huge_pages
,
2858 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2861 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2863 struct hstate
*h
= &default_hstate
;
2864 if (!hugepages_supported())
2867 "Node %d HugePages_Total: %5u\n"
2868 "Node %d HugePages_Free: %5u\n"
2869 "Node %d HugePages_Surp: %5u\n",
2870 nid
, h
->nr_huge_pages_node
[nid
],
2871 nid
, h
->free_huge_pages_node
[nid
],
2872 nid
, h
->surplus_huge_pages_node
[nid
]);
2875 void hugetlb_show_meminfo(void)
2880 if (!hugepages_supported())
2883 for_each_node_state(nid
, N_MEMORY
)
2885 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2887 h
->nr_huge_pages_node
[nid
],
2888 h
->free_huge_pages_node
[nid
],
2889 h
->surplus_huge_pages_node
[nid
],
2890 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2893 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
2895 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
2896 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
2899 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2900 unsigned long hugetlb_total_pages(void)
2903 unsigned long nr_total_pages
= 0;
2906 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2907 return nr_total_pages
;
2910 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2914 spin_lock(&hugetlb_lock
);
2916 * When cpuset is configured, it breaks the strict hugetlb page
2917 * reservation as the accounting is done on a global variable. Such
2918 * reservation is completely rubbish in the presence of cpuset because
2919 * the reservation is not checked against page availability for the
2920 * current cpuset. Application can still potentially OOM'ed by kernel
2921 * with lack of free htlb page in cpuset that the task is in.
2922 * Attempt to enforce strict accounting with cpuset is almost
2923 * impossible (or too ugly) because cpuset is too fluid that
2924 * task or memory node can be dynamically moved between cpusets.
2926 * The change of semantics for shared hugetlb mapping with cpuset is
2927 * undesirable. However, in order to preserve some of the semantics,
2928 * we fall back to check against current free page availability as
2929 * a best attempt and hopefully to minimize the impact of changing
2930 * semantics that cpuset has.
2933 if (gather_surplus_pages(h
, delta
) < 0)
2936 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2937 return_unused_surplus_pages(h
, delta
);
2944 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2947 spin_unlock(&hugetlb_lock
);
2951 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2953 struct resv_map
*resv
= vma_resv_map(vma
);
2956 * This new VMA should share its siblings reservation map if present.
2957 * The VMA will only ever have a valid reservation map pointer where
2958 * it is being copied for another still existing VMA. As that VMA
2959 * has a reference to the reservation map it cannot disappear until
2960 * after this open call completes. It is therefore safe to take a
2961 * new reference here without additional locking.
2963 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2964 kref_get(&resv
->refs
);
2967 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2969 struct hstate
*h
= hstate_vma(vma
);
2970 struct resv_map
*resv
= vma_resv_map(vma
);
2971 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2972 unsigned long reserve
, start
, end
;
2975 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2978 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2979 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2981 reserve
= (end
- start
) - region_count(resv
, start
, end
);
2983 kref_put(&resv
->refs
, resv_map_release
);
2987 * Decrement reserve counts. The global reserve count may be
2988 * adjusted if the subpool has a minimum size.
2990 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
2991 hugetlb_acct_memory(h
, -gbl_reserve
);
2996 * We cannot handle pagefaults against hugetlb pages at all. They cause
2997 * handle_mm_fault() to try to instantiate regular-sized pages in the
2998 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3001 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
3007 const struct vm_operations_struct hugetlb_vm_ops
= {
3008 .fault
= hugetlb_vm_op_fault
,
3009 .open
= hugetlb_vm_op_open
,
3010 .close
= hugetlb_vm_op_close
,
3013 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3019 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3020 vma
->vm_page_prot
)));
3022 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3023 vma
->vm_page_prot
));
3025 entry
= pte_mkyoung(entry
);
3026 entry
= pte_mkhuge(entry
);
3027 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3032 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3033 unsigned long address
, pte_t
*ptep
)
3037 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3038 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3039 update_mmu_cache(vma
, address
, ptep
);
3042 static int is_hugetlb_entry_migration(pte_t pte
)
3046 if (huge_pte_none(pte
) || pte_present(pte
))
3048 swp
= pte_to_swp_entry(pte
);
3049 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3055 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3059 if (huge_pte_none(pte
) || pte_present(pte
))
3061 swp
= pte_to_swp_entry(pte
);
3062 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3068 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3069 struct vm_area_struct
*vma
)
3071 pte_t
*src_pte
, *dst_pte
, entry
;
3072 struct page
*ptepage
;
3075 struct hstate
*h
= hstate_vma(vma
);
3076 unsigned long sz
= huge_page_size(h
);
3077 unsigned long mmun_start
; /* For mmu_notifiers */
3078 unsigned long mmun_end
; /* For mmu_notifiers */
3081 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3083 mmun_start
= vma
->vm_start
;
3084 mmun_end
= vma
->vm_end
;
3086 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
3088 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3089 spinlock_t
*src_ptl
, *dst_ptl
;
3090 src_pte
= huge_pte_offset(src
, addr
);
3093 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3099 /* If the pagetables are shared don't copy or take references */
3100 if (dst_pte
== src_pte
)
3103 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3104 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3105 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3106 entry
= huge_ptep_get(src_pte
);
3107 if (huge_pte_none(entry
)) { /* skip none entry */
3109 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3110 is_hugetlb_entry_hwpoisoned(entry
))) {
3111 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3113 if (is_write_migration_entry(swp_entry
) && cow
) {
3115 * COW mappings require pages in both
3116 * parent and child to be set to read.
3118 make_migration_entry_read(&swp_entry
);
3119 entry
= swp_entry_to_pte(swp_entry
);
3120 set_huge_pte_at(src
, addr
, src_pte
, entry
);
3122 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3125 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3126 mmu_notifier_invalidate_range(src
, mmun_start
,
3129 entry
= huge_ptep_get(src_pte
);
3130 ptepage
= pte_page(entry
);
3132 page_dup_rmap(ptepage
);
3133 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3134 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3136 spin_unlock(src_ptl
);
3137 spin_unlock(dst_ptl
);
3141 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
3146 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3147 unsigned long start
, unsigned long end
,
3148 struct page
*ref_page
)
3150 int force_flush
= 0;
3151 struct mm_struct
*mm
= vma
->vm_mm
;
3152 unsigned long address
;
3157 struct hstate
*h
= hstate_vma(vma
);
3158 unsigned long sz
= huge_page_size(h
);
3159 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
3160 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
3162 WARN_ON(!is_vm_hugetlb_page(vma
));
3163 BUG_ON(start
& ~huge_page_mask(h
));
3164 BUG_ON(end
& ~huge_page_mask(h
));
3166 tlb_start_vma(tlb
, vma
);
3167 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3170 for (; address
< end
; address
+= sz
) {
3171 ptep
= huge_pte_offset(mm
, address
);
3175 ptl
= huge_pte_lock(h
, mm
, ptep
);
3176 if (huge_pmd_unshare(mm
, &address
, ptep
))
3179 pte
= huge_ptep_get(ptep
);
3180 if (huge_pte_none(pte
))
3184 * Migrating hugepage or HWPoisoned hugepage is already
3185 * unmapped and its refcount is dropped, so just clear pte here.
3187 if (unlikely(!pte_present(pte
))) {
3188 huge_pte_clear(mm
, address
, ptep
);
3192 page
= pte_page(pte
);
3194 * If a reference page is supplied, it is because a specific
3195 * page is being unmapped, not a range. Ensure the page we
3196 * are about to unmap is the actual page of interest.
3199 if (page
!= ref_page
)
3203 * Mark the VMA as having unmapped its page so that
3204 * future faults in this VMA will fail rather than
3205 * looking like data was lost
3207 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3210 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3211 tlb_remove_tlb_entry(tlb
, ptep
, address
);
3212 if (huge_pte_dirty(pte
))
3213 set_page_dirty(page
);
3215 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3216 page_remove_rmap(page
);
3217 force_flush
= !__tlb_remove_page(tlb
, page
);
3223 /* Bail out after unmapping reference page if supplied */
3232 * mmu_gather ran out of room to batch pages, we break out of
3233 * the PTE lock to avoid doing the potential expensive TLB invalidate
3234 * and page-free while holding it.
3239 if (address
< end
&& !ref_page
)
3242 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3243 tlb_end_vma(tlb
, vma
);
3246 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3247 struct vm_area_struct
*vma
, unsigned long start
,
3248 unsigned long end
, struct page
*ref_page
)
3250 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3253 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3254 * test will fail on a vma being torn down, and not grab a page table
3255 * on its way out. We're lucky that the flag has such an appropriate
3256 * name, and can in fact be safely cleared here. We could clear it
3257 * before the __unmap_hugepage_range above, but all that's necessary
3258 * is to clear it before releasing the i_mmap_rwsem. This works
3259 * because in the context this is called, the VMA is about to be
3260 * destroyed and the i_mmap_rwsem is held.
3262 vma
->vm_flags
&= ~VM_MAYSHARE
;
3265 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3266 unsigned long end
, struct page
*ref_page
)
3268 struct mm_struct
*mm
;
3269 struct mmu_gather tlb
;
3273 tlb_gather_mmu(&tlb
, mm
, start
, end
);
3274 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3275 tlb_finish_mmu(&tlb
, start
, end
);
3279 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3280 * mappping it owns the reserve page for. The intention is to unmap the page
3281 * from other VMAs and let the children be SIGKILLed if they are faulting the
3284 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3285 struct page
*page
, unsigned long address
)
3287 struct hstate
*h
= hstate_vma(vma
);
3288 struct vm_area_struct
*iter_vma
;
3289 struct address_space
*mapping
;
3293 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3294 * from page cache lookup which is in HPAGE_SIZE units.
3296 address
= address
& huge_page_mask(h
);
3297 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3299 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
3302 * Take the mapping lock for the duration of the table walk. As
3303 * this mapping should be shared between all the VMAs,
3304 * __unmap_hugepage_range() is called as the lock is already held
3306 i_mmap_lock_write(mapping
);
3307 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3308 /* Do not unmap the current VMA */
3309 if (iter_vma
== vma
)
3313 * Shared VMAs have their own reserves and do not affect
3314 * MAP_PRIVATE accounting but it is possible that a shared
3315 * VMA is using the same page so check and skip such VMAs.
3317 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3321 * Unmap the page from other VMAs without their own reserves.
3322 * They get marked to be SIGKILLed if they fault in these
3323 * areas. This is because a future no-page fault on this VMA
3324 * could insert a zeroed page instead of the data existing
3325 * from the time of fork. This would look like data corruption
3327 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3328 unmap_hugepage_range(iter_vma
, address
,
3329 address
+ huge_page_size(h
), page
);
3331 i_mmap_unlock_write(mapping
);
3335 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3336 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3337 * cannot race with other handlers or page migration.
3338 * Keep the pte_same checks anyway to make transition from the mutex easier.
3340 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3341 unsigned long address
, pte_t
*ptep
, pte_t pte
,
3342 struct page
*pagecache_page
, spinlock_t
*ptl
)
3344 struct hstate
*h
= hstate_vma(vma
);
3345 struct page
*old_page
, *new_page
;
3346 int ret
= 0, outside_reserve
= 0;
3347 unsigned long mmun_start
; /* For mmu_notifiers */
3348 unsigned long mmun_end
; /* For mmu_notifiers */
3350 old_page
= pte_page(pte
);
3353 /* If no-one else is actually using this page, avoid the copy
3354 * and just make the page writable */
3355 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3356 page_move_anon_rmap(old_page
, vma
, address
);
3357 set_huge_ptep_writable(vma
, address
, ptep
);
3362 * If the process that created a MAP_PRIVATE mapping is about to
3363 * perform a COW due to a shared page count, attempt to satisfy
3364 * the allocation without using the existing reserves. The pagecache
3365 * page is used to determine if the reserve at this address was
3366 * consumed or not. If reserves were used, a partial faulted mapping
3367 * at the time of fork() could consume its reserves on COW instead
3368 * of the full address range.
3370 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3371 old_page
!= pagecache_page
)
3372 outside_reserve
= 1;
3374 page_cache_get(old_page
);
3377 * Drop page table lock as buddy allocator may be called. It will
3378 * be acquired again before returning to the caller, as expected.
3381 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
3383 if (IS_ERR(new_page
)) {
3385 * If a process owning a MAP_PRIVATE mapping fails to COW,
3386 * it is due to references held by a child and an insufficient
3387 * huge page pool. To guarantee the original mappers
3388 * reliability, unmap the page from child processes. The child
3389 * may get SIGKILLed if it later faults.
3391 if (outside_reserve
) {
3392 page_cache_release(old_page
);
3393 BUG_ON(huge_pte_none(pte
));
3394 unmap_ref_private(mm
, vma
, old_page
, address
);
3395 BUG_ON(huge_pte_none(pte
));
3397 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
3399 pte_same(huge_ptep_get(ptep
), pte
)))
3400 goto retry_avoidcopy
;
3402 * race occurs while re-acquiring page table
3403 * lock, and our job is done.
3408 ret
= (PTR_ERR(new_page
) == -ENOMEM
) ?
3409 VM_FAULT_OOM
: VM_FAULT_SIGBUS
;
3410 goto out_release_old
;
3414 * When the original hugepage is shared one, it does not have
3415 * anon_vma prepared.
3417 if (unlikely(anon_vma_prepare(vma
))) {
3419 goto out_release_all
;
3422 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3423 pages_per_huge_page(h
));
3424 __SetPageUptodate(new_page
);
3425 set_page_huge_active(new_page
);
3427 mmun_start
= address
& huge_page_mask(h
);
3428 mmun_end
= mmun_start
+ huge_page_size(h
);
3429 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3432 * Retake the page table lock to check for racing updates
3433 * before the page tables are altered
3436 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
3437 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3438 ClearPagePrivate(new_page
);
3441 huge_ptep_clear_flush(vma
, address
, ptep
);
3442 mmu_notifier_invalidate_range(mm
, mmun_start
, mmun_end
);
3443 set_huge_pte_at(mm
, address
, ptep
,
3444 make_huge_pte(vma
, new_page
, 1));
3445 page_remove_rmap(old_page
);
3446 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
3447 /* Make the old page be freed below */
3448 new_page
= old_page
;
3451 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3453 page_cache_release(new_page
);
3455 page_cache_release(old_page
);
3457 spin_lock(ptl
); /* Caller expects lock to be held */
3461 /* Return the pagecache page at a given address within a VMA */
3462 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3463 struct vm_area_struct
*vma
, unsigned long address
)
3465 struct address_space
*mapping
;
3468 mapping
= vma
->vm_file
->f_mapping
;
3469 idx
= vma_hugecache_offset(h
, vma
, address
);
3471 return find_lock_page(mapping
, idx
);
3475 * Return whether there is a pagecache page to back given address within VMA.
3476 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3478 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3479 struct vm_area_struct
*vma
, unsigned long address
)
3481 struct address_space
*mapping
;
3485 mapping
= vma
->vm_file
->f_mapping
;
3486 idx
= vma_hugecache_offset(h
, vma
, address
);
3488 page
= find_get_page(mapping
, idx
);
3491 return page
!= NULL
;
3494 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3497 struct inode
*inode
= mapping
->host
;
3498 struct hstate
*h
= hstate_inode(inode
);
3499 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3503 ClearPagePrivate(page
);
3505 spin_lock(&inode
->i_lock
);
3506 inode
->i_blocks
+= blocks_per_huge_page(h
);
3507 spin_unlock(&inode
->i_lock
);
3511 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3512 struct address_space
*mapping
, pgoff_t idx
,
3513 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3515 struct hstate
*h
= hstate_vma(vma
);
3516 int ret
= VM_FAULT_SIGBUS
;
3524 * Currently, we are forced to kill the process in the event the
3525 * original mapper has unmapped pages from the child due to a failed
3526 * COW. Warn that such a situation has occurred as it may not be obvious
3528 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3529 pr_warning("PID %d killed due to inadequate hugepage pool\n",
3535 * Use page lock to guard against racing truncation
3536 * before we get page_table_lock.
3539 page
= find_lock_page(mapping
, idx
);
3541 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3544 page
= alloc_huge_page(vma
, address
, 0);
3546 ret
= PTR_ERR(page
);
3550 ret
= VM_FAULT_SIGBUS
;
3553 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3554 __SetPageUptodate(page
);
3555 set_page_huge_active(page
);
3557 if (vma
->vm_flags
& VM_MAYSHARE
) {
3558 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3567 if (unlikely(anon_vma_prepare(vma
))) {
3569 goto backout_unlocked
;
3575 * If memory error occurs between mmap() and fault, some process
3576 * don't have hwpoisoned swap entry for errored virtual address.
3577 * So we need to block hugepage fault by PG_hwpoison bit check.
3579 if (unlikely(PageHWPoison(page
))) {
3580 ret
= VM_FAULT_HWPOISON
|
3581 VM_FAULT_SET_HINDEX(hstate_index(h
));
3582 goto backout_unlocked
;
3587 * If we are going to COW a private mapping later, we examine the
3588 * pending reservations for this page now. This will ensure that
3589 * any allocations necessary to record that reservation occur outside
3592 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3593 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3595 goto backout_unlocked
;
3597 /* Just decrements count, does not deallocate */
3598 vma_end_reservation(h
, vma
, address
);
3601 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
3603 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3608 if (!huge_pte_none(huge_ptep_get(ptep
)))
3612 ClearPagePrivate(page
);
3613 hugepage_add_new_anon_rmap(page
, vma
, address
);
3615 page_dup_rmap(page
);
3616 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
3617 && (vma
->vm_flags
& VM_SHARED
)));
3618 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
3620 hugetlb_count_add(pages_per_huge_page(h
), mm
);
3621 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3622 /* Optimization, do the COW without a second fault */
3623 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
, ptl
);
3640 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3641 struct vm_area_struct
*vma
,
3642 struct address_space
*mapping
,
3643 pgoff_t idx
, unsigned long address
)
3645 unsigned long key
[2];
3648 if (vma
->vm_flags
& VM_SHARED
) {
3649 key
[0] = (unsigned long) mapping
;
3652 key
[0] = (unsigned long) mm
;
3653 key
[1] = address
>> huge_page_shift(h
);
3656 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
3658 return hash
& (num_fault_mutexes
- 1);
3662 * For uniprocesor systems we always use a single mutex, so just
3663 * return 0 and avoid the hashing overhead.
3665 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3666 struct vm_area_struct
*vma
,
3667 struct address_space
*mapping
,
3668 pgoff_t idx
, unsigned long address
)
3674 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3675 unsigned long address
, unsigned int flags
)
3682 struct page
*page
= NULL
;
3683 struct page
*pagecache_page
= NULL
;
3684 struct hstate
*h
= hstate_vma(vma
);
3685 struct address_space
*mapping
;
3686 int need_wait_lock
= 0;
3688 address
&= huge_page_mask(h
);
3690 ptep
= huge_pte_offset(mm
, address
);
3692 entry
= huge_ptep_get(ptep
);
3693 if (unlikely(is_hugetlb_entry_migration(entry
))) {
3694 migration_entry_wait_huge(vma
, mm
, ptep
);
3696 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
3697 return VM_FAULT_HWPOISON_LARGE
|
3698 VM_FAULT_SET_HINDEX(hstate_index(h
));
3701 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
3703 return VM_FAULT_OOM
;
3705 mapping
= vma
->vm_file
->f_mapping
;
3706 idx
= vma_hugecache_offset(h
, vma
, address
);
3709 * Serialize hugepage allocation and instantiation, so that we don't
3710 * get spurious allocation failures if two CPUs race to instantiate
3711 * the same page in the page cache.
3713 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
3714 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3716 entry
= huge_ptep_get(ptep
);
3717 if (huge_pte_none(entry
)) {
3718 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3725 * entry could be a migration/hwpoison entry at this point, so this
3726 * check prevents the kernel from going below assuming that we have
3727 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3728 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3731 if (!pte_present(entry
))
3735 * If we are going to COW the mapping later, we examine the pending
3736 * reservations for this page now. This will ensure that any
3737 * allocations necessary to record that reservation occur outside the
3738 * spinlock. For private mappings, we also lookup the pagecache
3739 * page now as it is used to determine if a reservation has been
3742 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3743 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3747 /* Just decrements count, does not deallocate */
3748 vma_end_reservation(h
, vma
, address
);
3750 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3751 pagecache_page
= hugetlbfs_pagecache_page(h
,
3755 ptl
= huge_pte_lock(h
, mm
, ptep
);
3757 /* Check for a racing update before calling hugetlb_cow */
3758 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3762 * hugetlb_cow() requires page locks of pte_page(entry) and
3763 * pagecache_page, so here we need take the former one
3764 * when page != pagecache_page or !pagecache_page.
3766 page
= pte_page(entry
);
3767 if (page
!= pagecache_page
)
3768 if (!trylock_page(page
)) {
3775 if (flags
& FAULT_FLAG_WRITE
) {
3776 if (!huge_pte_write(entry
)) {
3777 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
3778 pagecache_page
, ptl
);
3781 entry
= huge_pte_mkdirty(entry
);
3783 entry
= pte_mkyoung(entry
);
3784 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3785 flags
& FAULT_FLAG_WRITE
))
3786 update_mmu_cache(vma
, address
, ptep
);
3788 if (page
!= pagecache_page
)
3794 if (pagecache_page
) {
3795 unlock_page(pagecache_page
);
3796 put_page(pagecache_page
);
3799 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3801 * Generally it's safe to hold refcount during waiting page lock. But
3802 * here we just wait to defer the next page fault to avoid busy loop and
3803 * the page is not used after unlocked before returning from the current
3804 * page fault. So we are safe from accessing freed page, even if we wait
3805 * here without taking refcount.
3808 wait_on_page_locked(page
);
3812 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3813 struct page
**pages
, struct vm_area_struct
**vmas
,
3814 unsigned long *position
, unsigned long *nr_pages
,
3815 long i
, unsigned int flags
)
3817 unsigned long pfn_offset
;
3818 unsigned long vaddr
= *position
;
3819 unsigned long remainder
= *nr_pages
;
3820 struct hstate
*h
= hstate_vma(vma
);
3822 while (vaddr
< vma
->vm_end
&& remainder
) {
3824 spinlock_t
*ptl
= NULL
;
3829 * If we have a pending SIGKILL, don't keep faulting pages and
3830 * potentially allocating memory.
3832 if (unlikely(fatal_signal_pending(current
))) {
3838 * Some archs (sparc64, sh*) have multiple pte_ts to
3839 * each hugepage. We have to make sure we get the
3840 * first, for the page indexing below to work.
3842 * Note that page table lock is not held when pte is null.
3844 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
3846 ptl
= huge_pte_lock(h
, mm
, pte
);
3847 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
3850 * When coredumping, it suits get_dump_page if we just return
3851 * an error where there's an empty slot with no huge pagecache
3852 * to back it. This way, we avoid allocating a hugepage, and
3853 * the sparse dumpfile avoids allocating disk blocks, but its
3854 * huge holes still show up with zeroes where they need to be.
3856 if (absent
&& (flags
& FOLL_DUMP
) &&
3857 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
3865 * We need call hugetlb_fault for both hugepages under migration
3866 * (in which case hugetlb_fault waits for the migration,) and
3867 * hwpoisoned hugepages (in which case we need to prevent the
3868 * caller from accessing to them.) In order to do this, we use
3869 * here is_swap_pte instead of is_hugetlb_entry_migration and
3870 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3871 * both cases, and because we can't follow correct pages
3872 * directly from any kind of swap entries.
3874 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
3875 ((flags
& FOLL_WRITE
) &&
3876 !huge_pte_write(huge_ptep_get(pte
)))) {
3881 ret
= hugetlb_fault(mm
, vma
, vaddr
,
3882 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
3883 if (!(ret
& VM_FAULT_ERROR
))
3890 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
3891 page
= pte_page(huge_ptep_get(pte
));
3894 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3895 get_page_foll(pages
[i
]);
3905 if (vaddr
< vma
->vm_end
&& remainder
&&
3906 pfn_offset
< pages_per_huge_page(h
)) {
3908 * We use pfn_offset to avoid touching the pageframes
3909 * of this compound page.
3915 *nr_pages
= remainder
;
3918 return i
? i
: -EFAULT
;
3921 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3922 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3924 struct mm_struct
*mm
= vma
->vm_mm
;
3925 unsigned long start
= address
;
3928 struct hstate
*h
= hstate_vma(vma
);
3929 unsigned long pages
= 0;
3931 BUG_ON(address
>= end
);
3932 flush_cache_range(vma
, address
, end
);
3934 mmu_notifier_invalidate_range_start(mm
, start
, end
);
3935 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
3936 for (; address
< end
; address
+= huge_page_size(h
)) {
3938 ptep
= huge_pte_offset(mm
, address
);
3941 ptl
= huge_pte_lock(h
, mm
, ptep
);
3942 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3947 pte
= huge_ptep_get(ptep
);
3948 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
3952 if (unlikely(is_hugetlb_entry_migration(pte
))) {
3953 swp_entry_t entry
= pte_to_swp_entry(pte
);
3955 if (is_write_migration_entry(entry
)) {
3958 make_migration_entry_read(&entry
);
3959 newpte
= swp_entry_to_pte(entry
);
3960 set_huge_pte_at(mm
, address
, ptep
, newpte
);
3966 if (!huge_pte_none(pte
)) {
3967 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3968 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3969 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3970 set_huge_pte_at(mm
, address
, ptep
, pte
);
3976 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
3977 * may have cleared our pud entry and done put_page on the page table:
3978 * once we release i_mmap_rwsem, another task can do the final put_page
3979 * and that page table be reused and filled with junk.
3981 flush_tlb_range(vma
, start
, end
);
3982 mmu_notifier_invalidate_range(mm
, start
, end
);
3983 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
3984 mmu_notifier_invalidate_range_end(mm
, start
, end
);
3986 return pages
<< h
->order
;
3989 int hugetlb_reserve_pages(struct inode
*inode
,
3991 struct vm_area_struct
*vma
,
3992 vm_flags_t vm_flags
)
3995 struct hstate
*h
= hstate_inode(inode
);
3996 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3997 struct resv_map
*resv_map
;
4001 * Only apply hugepage reservation if asked. At fault time, an
4002 * attempt will be made for VM_NORESERVE to allocate a page
4003 * without using reserves
4005 if (vm_flags
& VM_NORESERVE
)
4009 * Shared mappings base their reservation on the number of pages that
4010 * are already allocated on behalf of the file. Private mappings need
4011 * to reserve the full area even if read-only as mprotect() may be
4012 * called to make the mapping read-write. Assume !vma is a shm mapping
4014 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4015 resv_map
= inode_resv_map(inode
);
4017 chg
= region_chg(resv_map
, from
, to
);
4020 resv_map
= resv_map_alloc();
4026 set_vma_resv_map(vma
, resv_map
);
4027 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4036 * There must be enough pages in the subpool for the mapping. If
4037 * the subpool has a minimum size, there may be some global
4038 * reservations already in place (gbl_reserve).
4040 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4041 if (gbl_reserve
< 0) {
4047 * Check enough hugepages are available for the reservation.
4048 * Hand the pages back to the subpool if there are not
4050 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4052 /* put back original number of pages, chg */
4053 (void)hugepage_subpool_put_pages(spool
, chg
);
4058 * Account for the reservations made. Shared mappings record regions
4059 * that have reservations as they are shared by multiple VMAs.
4060 * When the last VMA disappears, the region map says how much
4061 * the reservation was and the page cache tells how much of
4062 * the reservation was consumed. Private mappings are per-VMA and
4063 * only the consumed reservations are tracked. When the VMA
4064 * disappears, the original reservation is the VMA size and the
4065 * consumed reservations are stored in the map. Hence, nothing
4066 * else has to be done for private mappings here
4068 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4069 long add
= region_add(resv_map
, from
, to
);
4071 if (unlikely(chg
> add
)) {
4073 * pages in this range were added to the reserve
4074 * map between region_chg and region_add. This
4075 * indicates a race with alloc_huge_page. Adjust
4076 * the subpool and reserve counts modified above
4077 * based on the difference.
4081 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4083 hugetlb_acct_memory(h
, -rsv_adjust
);
4088 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4089 region_abort(resv_map
, from
, to
);
4090 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4091 kref_put(&resv_map
->refs
, resv_map_release
);
4095 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4098 struct hstate
*h
= hstate_inode(inode
);
4099 struct resv_map
*resv_map
= inode_resv_map(inode
);
4101 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4105 chg
= region_del(resv_map
, start
, end
);
4107 * region_del() can fail in the rare case where a region
4108 * must be split and another region descriptor can not be
4109 * allocated. If end == LONG_MAX, it will not fail.
4115 spin_lock(&inode
->i_lock
);
4116 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4117 spin_unlock(&inode
->i_lock
);
4120 * If the subpool has a minimum size, the number of global
4121 * reservations to be released may be adjusted.
4123 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4124 hugetlb_acct_memory(h
, -gbl_reserve
);
4129 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4130 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4131 struct vm_area_struct
*vma
,
4132 unsigned long addr
, pgoff_t idx
)
4134 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4136 unsigned long sbase
= saddr
& PUD_MASK
;
4137 unsigned long s_end
= sbase
+ PUD_SIZE
;
4139 /* Allow segments to share if only one is marked locked */
4140 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4141 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4144 * match the virtual addresses, permission and the alignment of the
4147 if (pmd_index(addr
) != pmd_index(saddr
) ||
4148 vm_flags
!= svm_flags
||
4149 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4155 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4157 unsigned long base
= addr
& PUD_MASK
;
4158 unsigned long end
= base
+ PUD_SIZE
;
4161 * check on proper vm_flags and page table alignment
4163 if (vma
->vm_flags
& VM_MAYSHARE
&&
4164 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
4170 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4171 * and returns the corresponding pte. While this is not necessary for the
4172 * !shared pmd case because we can allocate the pmd later as well, it makes the
4173 * code much cleaner. pmd allocation is essential for the shared case because
4174 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4175 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4176 * bad pmd for sharing.
4178 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4180 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4181 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4182 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4184 struct vm_area_struct
*svma
;
4185 unsigned long saddr
;
4190 if (!vma_shareable(vma
, addr
))
4191 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4193 i_mmap_lock_write(mapping
);
4194 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4198 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4200 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
4203 get_page(virt_to_page(spte
));
4212 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, spte
);
4214 if (pud_none(*pud
)) {
4215 pud_populate(mm
, pud
,
4216 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4218 put_page(virt_to_page(spte
));
4223 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4224 i_mmap_unlock_write(mapping
);
4229 * unmap huge page backed by shared pte.
4231 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4232 * indicated by page_count > 1, unmap is achieved by clearing pud and
4233 * decrementing the ref count. If count == 1, the pte page is not shared.
4235 * called with page table lock held.
4237 * returns: 1 successfully unmapped a shared pte page
4238 * 0 the underlying pte page is not shared, or it is the last user
4240 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4242 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4243 pud_t
*pud
= pud_offset(pgd
, *addr
);
4245 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4246 if (page_count(virt_to_page(ptep
)) == 1)
4250 put_page(virt_to_page(ptep
));
4252 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4255 #define want_pmd_share() (1)
4256 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4257 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4262 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4266 #define want_pmd_share() (0)
4267 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4269 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4270 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4271 unsigned long addr
, unsigned long sz
)
4277 pgd
= pgd_offset(mm
, addr
);
4278 pud
= pud_alloc(mm
, pgd
, addr
);
4280 if (sz
== PUD_SIZE
) {
4283 BUG_ON(sz
!= PMD_SIZE
);
4284 if (want_pmd_share() && pud_none(*pud
))
4285 pte
= huge_pmd_share(mm
, addr
, pud
);
4287 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4290 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
4295 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
4301 pgd
= pgd_offset(mm
, addr
);
4302 if (pgd_present(*pgd
)) {
4303 pud
= pud_offset(pgd
, addr
);
4304 if (pud_present(*pud
)) {
4306 return (pte_t
*)pud
;
4307 pmd
= pmd_offset(pud
, addr
);
4310 return (pte_t
*) pmd
;
4313 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4316 * These functions are overwritable if your architecture needs its own
4319 struct page
* __weak
4320 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
4323 return ERR_PTR(-EINVAL
);
4326 struct page
* __weak
4327 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
4328 pmd_t
*pmd
, int flags
)
4330 struct page
*page
= NULL
;
4333 ptl
= pmd_lockptr(mm
, pmd
);
4336 * make sure that the address range covered by this pmd is not
4337 * unmapped from other threads.
4339 if (!pmd_huge(*pmd
))
4341 if (pmd_present(*pmd
)) {
4342 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
4343 if (flags
& FOLL_GET
)
4346 if (is_hugetlb_entry_migration(huge_ptep_get((pte_t
*)pmd
))) {
4348 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
4352 * hwpoisoned entry is treated as no_page_table in
4353 * follow_page_mask().
4361 struct page
* __weak
4362 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
4363 pud_t
*pud
, int flags
)
4365 if (flags
& FOLL_GET
)
4368 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
4371 #ifdef CONFIG_MEMORY_FAILURE
4374 * This function is called from memory failure code.
4375 * Assume the caller holds page lock of the head page.
4377 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
4379 struct hstate
*h
= page_hstate(hpage
);
4380 int nid
= page_to_nid(hpage
);
4383 spin_lock(&hugetlb_lock
);
4385 * Just checking !page_huge_active is not enough, because that could be
4386 * an isolated/hwpoisoned hugepage (which have >0 refcount).
4388 if (!page_huge_active(hpage
) && !page_count(hpage
)) {
4390 * Hwpoisoned hugepage isn't linked to activelist or freelist,
4391 * but dangling hpage->lru can trigger list-debug warnings
4392 * (this happens when we call unpoison_memory() on it),
4393 * so let it point to itself with list_del_init().
4395 list_del_init(&hpage
->lru
);
4396 set_page_refcounted(hpage
);
4397 h
->free_huge_pages
--;
4398 h
->free_huge_pages_node
[nid
]--;
4401 spin_unlock(&hugetlb_lock
);
4406 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
4410 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4411 spin_lock(&hugetlb_lock
);
4412 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
4416 clear_page_huge_active(page
);
4417 list_move_tail(&page
->lru
, list
);
4419 spin_unlock(&hugetlb_lock
);
4423 void putback_active_hugepage(struct page
*page
)
4425 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4426 spin_lock(&hugetlb_lock
);
4427 set_page_huge_active(page
);
4428 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
4429 spin_unlock(&hugetlb_lock
);