1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.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/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/mmdebug.h>
23 #include <linux/sched/signal.h>
24 #include <linux/rmap.h>
25 #include <linux/string_helpers.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
28 #include <linux/jhash.h>
29 #include <linux/numa.h>
30 #include <linux/llist.h>
33 #include <asm/pgtable.h>
37 #include <linux/hugetlb.h>
38 #include <linux/hugetlb_cgroup.h>
39 #include <linux/node.h>
40 #include <linux/userfaultfd_k.h>
41 #include <linux/page_owner.h>
44 int hugetlb_max_hstate __read_mostly
;
45 unsigned int default_hstate_idx
;
46 struct hstate hstates
[HUGE_MAX_HSTATE
];
48 * Minimum page order among possible hugepage sizes, set to a proper value
51 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
53 __initdata
LIST_HEAD(huge_boot_pages
);
55 /* for command line parsing */
56 static struct hstate
* __initdata parsed_hstate
;
57 static unsigned long __initdata default_hstate_max_huge_pages
;
58 static unsigned long __initdata default_hstate_size
;
59 static bool __initdata parsed_valid_hugepagesz
= true;
62 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
63 * free_huge_pages, and surplus_huge_pages.
65 DEFINE_SPINLOCK(hugetlb_lock
);
68 * Serializes faults on the same logical page. This is used to
69 * prevent spurious OOMs when the hugepage pool is fully utilized.
71 static int num_fault_mutexes
;
72 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
74 /* Forward declaration */
75 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
77 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
79 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
81 spin_unlock(&spool
->lock
);
83 /* If no pages are used, and no other handles to the subpool
84 * remain, give up any reservations mased on minimum size and
87 if (spool
->min_hpages
!= -1)
88 hugetlb_acct_memory(spool
->hstate
,
94 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
97 struct hugepage_subpool
*spool
;
99 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
103 spin_lock_init(&spool
->lock
);
105 spool
->max_hpages
= max_hpages
;
107 spool
->min_hpages
= min_hpages
;
109 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
113 spool
->rsv_hpages
= min_hpages
;
118 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
120 spin_lock(&spool
->lock
);
121 BUG_ON(!spool
->count
);
123 unlock_or_release_subpool(spool
);
127 * Subpool accounting for allocating and reserving pages.
128 * Return -ENOMEM if there are not enough resources to satisfy the
129 * the request. Otherwise, return the number of pages by which the
130 * global pools must be adjusted (upward). The returned value may
131 * only be different than the passed value (delta) in the case where
132 * a subpool minimum size must be manitained.
134 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
142 spin_lock(&spool
->lock
);
144 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
145 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
146 spool
->used_hpages
+= delta
;
153 /* minimum size accounting */
154 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
155 if (delta
> spool
->rsv_hpages
) {
157 * Asking for more reserves than those already taken on
158 * behalf of subpool. Return difference.
160 ret
= delta
- spool
->rsv_hpages
;
161 spool
->rsv_hpages
= 0;
163 ret
= 0; /* reserves already accounted for */
164 spool
->rsv_hpages
-= delta
;
169 spin_unlock(&spool
->lock
);
174 * Subpool accounting for freeing and unreserving pages.
175 * Return the number of global page reservations that must be dropped.
176 * The return value may only be different than the passed value (delta)
177 * in the case where a subpool minimum size must be maintained.
179 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
187 spin_lock(&spool
->lock
);
189 if (spool
->max_hpages
!= -1) /* maximum size accounting */
190 spool
->used_hpages
-= delta
;
192 /* minimum size accounting */
193 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
194 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
197 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
199 spool
->rsv_hpages
+= delta
;
200 if (spool
->rsv_hpages
> spool
->min_hpages
)
201 spool
->rsv_hpages
= spool
->min_hpages
;
205 * If hugetlbfs_put_super couldn't free spool due to an outstanding
206 * quota reference, free it now.
208 unlock_or_release_subpool(spool
);
213 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
215 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
218 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
220 return subpool_inode(file_inode(vma
->vm_file
));
223 /* Helper that removes a struct file_region from the resv_map cache and returns
226 static struct file_region
*
227 get_file_region_entry_from_cache(struct resv_map
*resv
, long from
, long to
)
229 struct file_region
*nrg
= NULL
;
231 VM_BUG_ON(resv
->region_cache_count
<= 0);
233 resv
->region_cache_count
--;
234 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
, link
);
236 list_del(&nrg
->link
);
244 static void copy_hugetlb_cgroup_uncharge_info(struct file_region
*nrg
,
245 struct file_region
*rg
)
247 #ifdef CONFIG_CGROUP_HUGETLB
248 nrg
->reservation_counter
= rg
->reservation_counter
;
255 /* Helper that records hugetlb_cgroup uncharge info. */
256 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup
*h_cg
,
258 struct resv_map
*resv
,
259 struct file_region
*nrg
)
261 #ifdef CONFIG_CGROUP_HUGETLB
263 nrg
->reservation_counter
=
264 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
265 nrg
->css
= &h_cg
->css
;
266 if (!resv
->pages_per_hpage
)
267 resv
->pages_per_hpage
= pages_per_huge_page(h
);
268 /* pages_per_hpage should be the same for all entries in
271 VM_BUG_ON(resv
->pages_per_hpage
!= pages_per_huge_page(h
));
273 nrg
->reservation_counter
= NULL
;
279 static bool has_same_uncharge_info(struct file_region
*rg
,
280 struct file_region
*org
)
282 #ifdef CONFIG_CGROUP_HUGETLB
284 rg
->reservation_counter
== org
->reservation_counter
&&
292 static void coalesce_file_region(struct resv_map
*resv
, struct file_region
*rg
)
294 struct file_region
*nrg
= NULL
, *prg
= NULL
;
296 prg
= list_prev_entry(rg
, link
);
297 if (&prg
->link
!= &resv
->regions
&& prg
->to
== rg
->from
&&
298 has_same_uncharge_info(prg
, rg
)) {
304 coalesce_file_region(resv
, prg
);
308 nrg
= list_next_entry(rg
, link
);
309 if (&nrg
->link
!= &resv
->regions
&& nrg
->from
== rg
->to
&&
310 has_same_uncharge_info(nrg
, rg
)) {
311 nrg
->from
= rg
->from
;
316 coalesce_file_region(resv
, nrg
);
321 /* Must be called with resv->lock held. Calling this with count_only == true
322 * will count the number of pages to be added but will not modify the linked
323 * list. If regions_needed != NULL and count_only == true, then regions_needed
324 * will indicate the number of file_regions needed in the cache to carry out to
325 * add the regions for this range.
327 static long add_reservation_in_range(struct resv_map
*resv
, long f
, long t
,
328 struct hugetlb_cgroup
*h_cg
,
329 struct hstate
*h
, long *regions_needed
,
333 struct list_head
*head
= &resv
->regions
;
334 long last_accounted_offset
= f
;
335 struct file_region
*rg
= NULL
, *trg
= NULL
, *nrg
= NULL
;
340 /* In this loop, we essentially handle an entry for the range
341 * [last_accounted_offset, rg->from), at every iteration, with some
344 list_for_each_entry_safe(rg
, trg
, head
, link
) {
345 /* Skip irrelevant regions that start before our range. */
347 /* If this region ends after the last accounted offset,
348 * then we need to update last_accounted_offset.
350 if (rg
->to
> last_accounted_offset
)
351 last_accounted_offset
= rg
->to
;
355 /* When we find a region that starts beyond our range, we've
361 /* Add an entry for last_accounted_offset -> rg->from, and
362 * update last_accounted_offset.
364 if (rg
->from
> last_accounted_offset
) {
365 add
+= rg
->from
- last_accounted_offset
;
367 nrg
= get_file_region_entry_from_cache(
368 resv
, last_accounted_offset
, rg
->from
);
369 record_hugetlb_cgroup_uncharge_info(h_cg
, h
,
371 list_add(&nrg
->link
, rg
->link
.prev
);
372 coalesce_file_region(resv
, nrg
);
373 } else if (regions_needed
)
374 *regions_needed
+= 1;
377 last_accounted_offset
= rg
->to
;
380 /* Handle the case where our range extends beyond
381 * last_accounted_offset.
383 if (last_accounted_offset
< t
) {
384 add
+= t
- last_accounted_offset
;
386 nrg
= get_file_region_entry_from_cache(
387 resv
, last_accounted_offset
, t
);
388 record_hugetlb_cgroup_uncharge_info(h_cg
, h
, resv
, nrg
);
389 list_add(&nrg
->link
, rg
->link
.prev
);
390 coalesce_file_region(resv
, nrg
);
391 } else if (regions_needed
)
392 *regions_needed
+= 1;
399 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
401 static int allocate_file_region_entries(struct resv_map
*resv
,
403 __must_hold(&resv
->lock
)
405 struct list_head allocated_regions
;
406 int to_allocate
= 0, i
= 0;
407 struct file_region
*trg
= NULL
, *rg
= NULL
;
409 VM_BUG_ON(regions_needed
< 0);
411 INIT_LIST_HEAD(&allocated_regions
);
414 * Check for sufficient descriptors in the cache to accommodate
415 * the number of in progress add operations plus regions_needed.
417 * This is a while loop because when we drop the lock, some other call
418 * to region_add or region_del may have consumed some region_entries,
419 * so we keep looping here until we finally have enough entries for
420 * (adds_in_progress + regions_needed).
422 while (resv
->region_cache_count
<
423 (resv
->adds_in_progress
+ regions_needed
)) {
424 to_allocate
= resv
->adds_in_progress
+ regions_needed
-
425 resv
->region_cache_count
;
427 /* At this point, we should have enough entries in the cache
428 * for all the existings adds_in_progress. We should only be
429 * needing to allocate for regions_needed.
431 VM_BUG_ON(resv
->region_cache_count
< resv
->adds_in_progress
);
433 spin_unlock(&resv
->lock
);
434 for (i
= 0; i
< to_allocate
; i
++) {
435 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
438 list_add(&trg
->link
, &allocated_regions
);
441 spin_lock(&resv
->lock
);
443 list_for_each_entry_safe(rg
, trg
, &allocated_regions
, link
) {
445 list_add(&rg
->link
, &resv
->region_cache
);
446 resv
->region_cache_count
++;
453 list_for_each_entry_safe(rg
, trg
, &allocated_regions
, link
) {
461 * Add the huge page range represented by [f, t) to the reserve
462 * map. Regions will be taken from the cache to fill in this range.
463 * Sufficient regions should exist in the cache due to the previous
464 * call to region_chg with the same range, but in some cases the cache will not
465 * have sufficient entries due to races with other code doing region_add or
466 * region_del. The extra needed entries will be allocated.
468 * regions_needed is the out value provided by a previous call to region_chg.
470 * Return the number of new huge pages added to the map. This number is greater
471 * than or equal to zero. If file_region entries needed to be allocated for
472 * this operation and we were not able to allocate, it ruturns -ENOMEM.
473 * region_add of regions of length 1 never allocate file_regions and cannot
474 * fail; region_chg will always allocate at least 1 entry and a region_add for
475 * 1 page will only require at most 1 entry.
477 static long region_add(struct resv_map
*resv
, long f
, long t
,
478 long in_regions_needed
, struct hstate
*h
,
479 struct hugetlb_cgroup
*h_cg
)
481 long add
= 0, actual_regions_needed
= 0;
483 spin_lock(&resv
->lock
);
486 /* Count how many regions are actually needed to execute this add. */
487 add_reservation_in_range(resv
, f
, t
, NULL
, NULL
, &actual_regions_needed
,
491 * Check for sufficient descriptors in the cache to accommodate
492 * this add operation. Note that actual_regions_needed may be greater
493 * than in_regions_needed, as the resv_map may have been modified since
494 * the region_chg call. In this case, we need to make sure that we
495 * allocate extra entries, such that we have enough for all the
496 * existing adds_in_progress, plus the excess needed for this
499 if (actual_regions_needed
> in_regions_needed
&&
500 resv
->region_cache_count
<
501 resv
->adds_in_progress
+
502 (actual_regions_needed
- in_regions_needed
)) {
503 /* region_add operation of range 1 should never need to
504 * allocate file_region entries.
506 VM_BUG_ON(t
- f
<= 1);
508 if (allocate_file_region_entries(
509 resv
, actual_regions_needed
- in_regions_needed
)) {
516 add
= add_reservation_in_range(resv
, f
, t
, h_cg
, h
, NULL
, false);
518 resv
->adds_in_progress
-= in_regions_needed
;
520 spin_unlock(&resv
->lock
);
526 * Examine the existing reserve map and determine how many
527 * huge pages in the specified range [f, t) are NOT currently
528 * represented. This routine is called before a subsequent
529 * call to region_add that will actually modify the reserve
530 * map to add the specified range [f, t). region_chg does
531 * not change the number of huge pages represented by the
532 * map. A number of new file_region structures is added to the cache as a
533 * placeholder, for the subsequent region_add call to use. At least 1
534 * file_region structure is added.
536 * out_regions_needed is the number of regions added to the
537 * resv->adds_in_progress. This value needs to be provided to a follow up call
538 * to region_add or region_abort for proper accounting.
540 * Returns the number of huge pages that need to be added to the existing
541 * reservation map for the range [f, t). This number is greater or equal to
542 * zero. -ENOMEM is returned if a new file_region structure or cache entry
543 * is needed and can not be allocated.
545 static long region_chg(struct resv_map
*resv
, long f
, long t
,
546 long *out_regions_needed
)
550 spin_lock(&resv
->lock
);
552 /* Count how many hugepages in this range are NOT respresented. */
553 chg
= add_reservation_in_range(resv
, f
, t
, NULL
, NULL
,
554 out_regions_needed
, true);
556 if (*out_regions_needed
== 0)
557 *out_regions_needed
= 1;
559 if (allocate_file_region_entries(resv
, *out_regions_needed
))
562 resv
->adds_in_progress
+= *out_regions_needed
;
564 spin_unlock(&resv
->lock
);
569 * Abort the in progress add operation. The adds_in_progress field
570 * of the resv_map keeps track of the operations in progress between
571 * calls to region_chg and region_add. Operations are sometimes
572 * aborted after the call to region_chg. In such cases, region_abort
573 * is called to decrement the adds_in_progress counter. regions_needed
574 * is the value returned by the region_chg call, it is used to decrement
575 * the adds_in_progress counter.
577 * NOTE: The range arguments [f, t) are not needed or used in this
578 * routine. They are kept to make reading the calling code easier as
579 * arguments will match the associated region_chg call.
581 static void region_abort(struct resv_map
*resv
, long f
, long t
,
584 spin_lock(&resv
->lock
);
585 VM_BUG_ON(!resv
->region_cache_count
);
586 resv
->adds_in_progress
-= regions_needed
;
587 spin_unlock(&resv
->lock
);
591 * Delete the specified range [f, t) from the reserve map. If the
592 * t parameter is LONG_MAX, this indicates that ALL regions after f
593 * should be deleted. Locate the regions which intersect [f, t)
594 * and either trim, delete or split the existing regions.
596 * Returns the number of huge pages deleted from the reserve map.
597 * In the normal case, the return value is zero or more. In the
598 * case where a region must be split, a new region descriptor must
599 * be allocated. If the allocation fails, -ENOMEM will be returned.
600 * NOTE: If the parameter t == LONG_MAX, then we will never split
601 * a region and possibly return -ENOMEM. Callers specifying
602 * t == LONG_MAX do not need to check for -ENOMEM error.
604 static long region_del(struct resv_map
*resv
, long f
, long t
)
606 struct list_head
*head
= &resv
->regions
;
607 struct file_region
*rg
, *trg
;
608 struct file_region
*nrg
= NULL
;
612 spin_lock(&resv
->lock
);
613 list_for_each_entry_safe(rg
, trg
, head
, link
) {
615 * Skip regions before the range to be deleted. file_region
616 * ranges are normally of the form [from, to). However, there
617 * may be a "placeholder" entry in the map which is of the form
618 * (from, to) with from == to. Check for placeholder entries
619 * at the beginning of the range to be deleted.
621 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
627 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
629 * Check for an entry in the cache before dropping
630 * lock and attempting allocation.
633 resv
->region_cache_count
> resv
->adds_in_progress
) {
634 nrg
= list_first_entry(&resv
->region_cache
,
637 list_del(&nrg
->link
);
638 resv
->region_cache_count
--;
642 spin_unlock(&resv
->lock
);
643 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
651 /* New entry for end of split region */
655 copy_hugetlb_cgroup_uncharge_info(nrg
, rg
);
657 INIT_LIST_HEAD(&nrg
->link
);
659 /* Original entry is trimmed */
662 hugetlb_cgroup_uncharge_file_region(
663 resv
, rg
, nrg
->to
- nrg
->from
);
665 list_add(&nrg
->link
, &rg
->link
);
670 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
671 del
+= rg
->to
- rg
->from
;
672 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
679 if (f
<= rg
->from
) { /* Trim beginning of region */
683 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
685 } else { /* Trim end of region */
689 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
694 spin_unlock(&resv
->lock
);
700 * A rare out of memory error was encountered which prevented removal of
701 * the reserve map region for a page. The huge page itself was free'ed
702 * and removed from the page cache. This routine will adjust the subpool
703 * usage count, and the global reserve count if needed. By incrementing
704 * these counts, the reserve map entry which could not be deleted will
705 * appear as a "reserved" entry instead of simply dangling with incorrect
708 void hugetlb_fix_reserve_counts(struct inode
*inode
)
710 struct hugepage_subpool
*spool
= subpool_inode(inode
);
713 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
715 struct hstate
*h
= hstate_inode(inode
);
717 hugetlb_acct_memory(h
, 1);
722 * Count and return the number of huge pages in the reserve map
723 * that intersect with the range [f, t).
725 static long region_count(struct resv_map
*resv
, long f
, long t
)
727 struct list_head
*head
= &resv
->regions
;
728 struct file_region
*rg
;
731 spin_lock(&resv
->lock
);
732 /* Locate each segment we overlap with, and count that overlap. */
733 list_for_each_entry(rg
, head
, link
) {
742 seg_from
= max(rg
->from
, f
);
743 seg_to
= min(rg
->to
, t
);
745 chg
+= seg_to
- seg_from
;
747 spin_unlock(&resv
->lock
);
753 * Convert the address within this vma to the page offset within
754 * the mapping, in pagecache page units; huge pages here.
756 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
757 struct vm_area_struct
*vma
, unsigned long address
)
759 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
760 (vma
->vm_pgoff
>> huge_page_order(h
));
763 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
764 unsigned long address
)
766 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
768 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
771 * Return the size of the pages allocated when backing a VMA. In the majority
772 * cases this will be same size as used by the page table entries.
774 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
776 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
777 return vma
->vm_ops
->pagesize(vma
);
780 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
783 * Return the page size being used by the MMU to back a VMA. In the majority
784 * of cases, the page size used by the kernel matches the MMU size. On
785 * architectures where it differs, an architecture-specific 'strong'
786 * version of this symbol is required.
788 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
790 return vma_kernel_pagesize(vma
);
794 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
795 * bits of the reservation map pointer, which are always clear due to
798 #define HPAGE_RESV_OWNER (1UL << 0)
799 #define HPAGE_RESV_UNMAPPED (1UL << 1)
800 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
803 * These helpers are used to track how many pages are reserved for
804 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
805 * is guaranteed to have their future faults succeed.
807 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
808 * the reserve counters are updated with the hugetlb_lock held. It is safe
809 * to reset the VMA at fork() time as it is not in use yet and there is no
810 * chance of the global counters getting corrupted as a result of the values.
812 * The private mapping reservation is represented in a subtly different
813 * manner to a shared mapping. A shared mapping has a region map associated
814 * with the underlying file, this region map represents the backing file
815 * pages which have ever had a reservation assigned which this persists even
816 * after the page is instantiated. A private mapping has a region map
817 * associated with the original mmap which is attached to all VMAs which
818 * reference it, this region map represents those offsets which have consumed
819 * reservation ie. where pages have been instantiated.
821 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
823 return (unsigned long)vma
->vm_private_data
;
826 static void set_vma_private_data(struct vm_area_struct
*vma
,
829 vma
->vm_private_data
= (void *)value
;
833 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map
*resv_map
,
834 struct hugetlb_cgroup
*h_cg
,
837 #ifdef CONFIG_CGROUP_HUGETLB
839 resv_map
->reservation_counter
= NULL
;
840 resv_map
->pages_per_hpage
= 0;
841 resv_map
->css
= NULL
;
843 resv_map
->reservation_counter
=
844 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
845 resv_map
->pages_per_hpage
= pages_per_huge_page(h
);
846 resv_map
->css
= &h_cg
->css
;
851 struct resv_map
*resv_map_alloc(void)
853 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
854 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
856 if (!resv_map
|| !rg
) {
862 kref_init(&resv_map
->refs
);
863 spin_lock_init(&resv_map
->lock
);
864 INIT_LIST_HEAD(&resv_map
->regions
);
866 resv_map
->adds_in_progress
= 0;
868 * Initialize these to 0. On shared mappings, 0's here indicate these
869 * fields don't do cgroup accounting. On private mappings, these will be
870 * re-initialized to the proper values, to indicate that hugetlb cgroup
871 * reservations are to be un-charged from here.
873 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, NULL
, NULL
);
875 INIT_LIST_HEAD(&resv_map
->region_cache
);
876 list_add(&rg
->link
, &resv_map
->region_cache
);
877 resv_map
->region_cache_count
= 1;
882 void resv_map_release(struct kref
*ref
)
884 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
885 struct list_head
*head
= &resv_map
->region_cache
;
886 struct file_region
*rg
, *trg
;
888 /* Clear out any active regions before we release the map. */
889 region_del(resv_map
, 0, LONG_MAX
);
891 /* ... and any entries left in the cache */
892 list_for_each_entry_safe(rg
, trg
, head
, link
) {
897 VM_BUG_ON(resv_map
->adds_in_progress
);
902 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
905 * At inode evict time, i_mapping may not point to the original
906 * address space within the inode. This original address space
907 * contains the pointer to the resv_map. So, always use the
908 * address space embedded within the inode.
909 * The VERY common case is inode->mapping == &inode->i_data but,
910 * this may not be true for device special inodes.
912 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
915 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
917 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
918 if (vma
->vm_flags
& VM_MAYSHARE
) {
919 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
920 struct inode
*inode
= mapping
->host
;
922 return inode_resv_map(inode
);
925 return (struct resv_map
*)(get_vma_private_data(vma
) &
930 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
932 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
933 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
935 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
936 HPAGE_RESV_MASK
) | (unsigned long)map
);
939 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
941 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
942 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
944 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
947 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
949 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
951 return (get_vma_private_data(vma
) & flag
) != 0;
954 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
955 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
957 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
958 if (!(vma
->vm_flags
& VM_MAYSHARE
))
959 vma
->vm_private_data
= (void *)0;
962 /* Returns true if the VMA has associated reserve pages */
963 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
965 if (vma
->vm_flags
& VM_NORESERVE
) {
967 * This address is already reserved by other process(chg == 0),
968 * so, we should decrement reserved count. Without decrementing,
969 * reserve count remains after releasing inode, because this
970 * allocated page will go into page cache and is regarded as
971 * coming from reserved pool in releasing step. Currently, we
972 * don't have any other solution to deal with this situation
973 * properly, so add work-around here.
975 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
981 /* Shared mappings always use reserves */
982 if (vma
->vm_flags
& VM_MAYSHARE
) {
984 * We know VM_NORESERVE is not set. Therefore, there SHOULD
985 * be a region map for all pages. The only situation where
986 * there is no region map is if a hole was punched via
987 * fallocate. In this case, there really are no reverves to
988 * use. This situation is indicated if chg != 0.
997 * Only the process that called mmap() has reserves for
1000 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1002 * Like the shared case above, a hole punch or truncate
1003 * could have been performed on the private mapping.
1004 * Examine the value of chg to determine if reserves
1005 * actually exist or were previously consumed.
1006 * Very Subtle - The value of chg comes from a previous
1007 * call to vma_needs_reserves(). The reserve map for
1008 * private mappings has different (opposite) semantics
1009 * than that of shared mappings. vma_needs_reserves()
1010 * has already taken this difference in semantics into
1011 * account. Therefore, the meaning of chg is the same
1012 * as in the shared case above. Code could easily be
1013 * combined, but keeping it separate draws attention to
1014 * subtle differences.
1025 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
1027 int nid
= page_to_nid(page
);
1028 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
1029 h
->free_huge_pages
++;
1030 h
->free_huge_pages_node
[nid
]++;
1033 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
1037 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
1038 if (!PageHWPoison(page
))
1041 * if 'non-isolated free hugepage' not found on the list,
1042 * the allocation fails.
1044 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
1046 list_move(&page
->lru
, &h
->hugepage_activelist
);
1047 set_page_refcounted(page
);
1048 h
->free_huge_pages
--;
1049 h
->free_huge_pages_node
[nid
]--;
1053 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
1056 unsigned int cpuset_mems_cookie
;
1057 struct zonelist
*zonelist
;
1060 int node
= NUMA_NO_NODE
;
1062 zonelist
= node_zonelist(nid
, gfp_mask
);
1065 cpuset_mems_cookie
= read_mems_allowed_begin();
1066 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
1069 if (!cpuset_zone_allowed(zone
, gfp_mask
))
1072 * no need to ask again on the same node. Pool is node rather than
1075 if (zone_to_nid(zone
) == node
)
1077 node
= zone_to_nid(zone
);
1079 page
= dequeue_huge_page_node_exact(h
, node
);
1083 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
1089 /* Movability of hugepages depends on migration support. */
1090 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
1092 if (hugepage_movable_supported(h
))
1093 return GFP_HIGHUSER_MOVABLE
;
1095 return GFP_HIGHUSER
;
1098 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
1099 struct vm_area_struct
*vma
,
1100 unsigned long address
, int avoid_reserve
,
1104 struct mempolicy
*mpol
;
1106 nodemask_t
*nodemask
;
1110 * A child process with MAP_PRIVATE mappings created by their parent
1111 * have no page reserves. This check ensures that reservations are
1112 * not "stolen". The child may still get SIGKILLed
1114 if (!vma_has_reserves(vma
, chg
) &&
1115 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1118 /* If reserves cannot be used, ensure enough pages are in the pool */
1119 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1122 gfp_mask
= htlb_alloc_mask(h
);
1123 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1124 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
1125 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
1126 SetPagePrivate(page
);
1127 h
->resv_huge_pages
--;
1130 mpol_cond_put(mpol
);
1138 * common helper functions for hstate_next_node_to_{alloc|free}.
1139 * We may have allocated or freed a huge page based on a different
1140 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1141 * be outside of *nodes_allowed. Ensure that we use an allowed
1142 * node for alloc or free.
1144 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1146 nid
= next_node_in(nid
, *nodes_allowed
);
1147 VM_BUG_ON(nid
>= MAX_NUMNODES
);
1152 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1154 if (!node_isset(nid
, *nodes_allowed
))
1155 nid
= next_node_allowed(nid
, nodes_allowed
);
1160 * returns the previously saved node ["this node"] from which to
1161 * allocate a persistent huge page for the pool and advance the
1162 * next node from which to allocate, handling wrap at end of node
1165 static int hstate_next_node_to_alloc(struct hstate
*h
,
1166 nodemask_t
*nodes_allowed
)
1170 VM_BUG_ON(!nodes_allowed
);
1172 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1173 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1179 * helper for free_pool_huge_page() - return the previously saved
1180 * node ["this node"] from which to free a huge page. Advance the
1181 * next node id whether or not we find a free huge page to free so
1182 * that the next attempt to free addresses the next node.
1184 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1188 VM_BUG_ON(!nodes_allowed
);
1190 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1191 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1196 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1197 for (nr_nodes = nodes_weight(*mask); \
1199 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1202 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1203 for (nr_nodes = nodes_weight(*mask); \
1205 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1208 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1209 static void destroy_compound_gigantic_page(struct page
*page
,
1213 int nr_pages
= 1 << order
;
1214 struct page
*p
= page
+ 1;
1216 atomic_set(compound_mapcount_ptr(page
), 0);
1217 if (hpage_pincount_available(page
))
1218 atomic_set(compound_pincount_ptr(page
), 0);
1220 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1221 clear_compound_head(p
);
1222 set_page_refcounted(p
);
1225 set_compound_order(page
, 0);
1226 __ClearPageHead(page
);
1229 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1231 free_contig_range(page_to_pfn(page
), 1 << order
);
1234 #ifdef CONFIG_CONTIG_ALLOC
1235 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1236 int nid
, nodemask_t
*nodemask
)
1238 unsigned long nr_pages
= 1UL << huge_page_order(h
);
1240 return alloc_contig_pages(nr_pages
, gfp_mask
, nid
, nodemask
);
1243 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1244 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1245 #else /* !CONFIG_CONTIG_ALLOC */
1246 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1247 int nid
, nodemask_t
*nodemask
)
1251 #endif /* CONFIG_CONTIG_ALLOC */
1253 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1254 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1255 int nid
, nodemask_t
*nodemask
)
1259 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1260 static inline void destroy_compound_gigantic_page(struct page
*page
,
1261 unsigned int order
) { }
1264 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1268 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1272 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1273 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1274 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1275 1 << PG_referenced
| 1 << PG_dirty
|
1276 1 << PG_active
| 1 << PG_private
|
1279 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1280 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page
), page
);
1281 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1282 set_page_refcounted(page
);
1283 if (hstate_is_gigantic(h
)) {
1284 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1285 free_gigantic_page(page
, huge_page_order(h
));
1287 __free_pages(page
, huge_page_order(h
));
1291 struct hstate
*size_to_hstate(unsigned long size
)
1295 for_each_hstate(h
) {
1296 if (huge_page_size(h
) == size
)
1303 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1304 * to hstate->hugepage_activelist.)
1306 * This function can be called for tail pages, but never returns true for them.
1308 bool page_huge_active(struct page
*page
)
1310 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1311 return PageHead(page
) && PagePrivate(&page
[1]);
1314 /* never called for tail page */
1315 static void set_page_huge_active(struct page
*page
)
1317 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1318 SetPagePrivate(&page
[1]);
1321 static void clear_page_huge_active(struct page
*page
)
1323 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1324 ClearPagePrivate(&page
[1]);
1328 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1331 static inline bool PageHugeTemporary(struct page
*page
)
1333 if (!PageHuge(page
))
1336 return (unsigned long)page
[2].mapping
== -1U;
1339 static inline void SetPageHugeTemporary(struct page
*page
)
1341 page
[2].mapping
= (void *)-1U;
1344 static inline void ClearPageHugeTemporary(struct page
*page
)
1346 page
[2].mapping
= NULL
;
1349 static void __free_huge_page(struct page
*page
)
1352 * Can't pass hstate in here because it is called from the
1353 * compound page destructor.
1355 struct hstate
*h
= page_hstate(page
);
1356 int nid
= page_to_nid(page
);
1357 struct hugepage_subpool
*spool
=
1358 (struct hugepage_subpool
*)page_private(page
);
1359 bool restore_reserve
;
1361 VM_BUG_ON_PAGE(page_count(page
), page
);
1362 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1364 set_page_private(page
, 0);
1365 page
->mapping
= NULL
;
1366 restore_reserve
= PagePrivate(page
);
1367 ClearPagePrivate(page
);
1370 * If PagePrivate() was set on page, page allocation consumed a
1371 * reservation. If the page was associated with a subpool, there
1372 * would have been a page reserved in the subpool before allocation
1373 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1374 * reservtion, do not call hugepage_subpool_put_pages() as this will
1375 * remove the reserved page from the subpool.
1377 if (!restore_reserve
) {
1379 * A return code of zero implies that the subpool will be
1380 * under its minimum size if the reservation is not restored
1381 * after page is free. Therefore, force restore_reserve
1384 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1385 restore_reserve
= true;
1388 spin_lock(&hugetlb_lock
);
1389 clear_page_huge_active(page
);
1390 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1391 pages_per_huge_page(h
), page
);
1392 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h
),
1393 pages_per_huge_page(h
), page
);
1394 if (restore_reserve
)
1395 h
->resv_huge_pages
++;
1397 if (PageHugeTemporary(page
)) {
1398 list_del(&page
->lru
);
1399 ClearPageHugeTemporary(page
);
1400 update_and_free_page(h
, page
);
1401 } else if (h
->surplus_huge_pages_node
[nid
]) {
1402 /* remove the page from active list */
1403 list_del(&page
->lru
);
1404 update_and_free_page(h
, page
);
1405 h
->surplus_huge_pages
--;
1406 h
->surplus_huge_pages_node
[nid
]--;
1408 arch_clear_hugepage_flags(page
);
1409 enqueue_huge_page(h
, page
);
1411 spin_unlock(&hugetlb_lock
);
1415 * As free_huge_page() can be called from a non-task context, we have
1416 * to defer the actual freeing in a workqueue to prevent potential
1417 * hugetlb_lock deadlock.
1419 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1420 * be freed and frees them one-by-one. As the page->mapping pointer is
1421 * going to be cleared in __free_huge_page() anyway, it is reused as the
1422 * llist_node structure of a lockless linked list of huge pages to be freed.
1424 static LLIST_HEAD(hpage_freelist
);
1426 static void free_hpage_workfn(struct work_struct
*work
)
1428 struct llist_node
*node
;
1431 node
= llist_del_all(&hpage_freelist
);
1434 page
= container_of((struct address_space
**)node
,
1435 struct page
, mapping
);
1437 __free_huge_page(page
);
1440 static DECLARE_WORK(free_hpage_work
, free_hpage_workfn
);
1442 void free_huge_page(struct page
*page
)
1445 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1449 * Only call schedule_work() if hpage_freelist is previously
1450 * empty. Otherwise, schedule_work() had been called but the
1451 * workfn hasn't retrieved the list yet.
1453 if (llist_add((struct llist_node
*)&page
->mapping
,
1455 schedule_work(&free_hpage_work
);
1459 __free_huge_page(page
);
1462 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1464 INIT_LIST_HEAD(&page
->lru
);
1465 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1466 spin_lock(&hugetlb_lock
);
1467 set_hugetlb_cgroup(page
, NULL
);
1468 set_hugetlb_cgroup_rsvd(page
, NULL
);
1470 h
->nr_huge_pages_node
[nid
]++;
1471 spin_unlock(&hugetlb_lock
);
1474 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1477 int nr_pages
= 1 << order
;
1478 struct page
*p
= page
+ 1;
1480 /* we rely on prep_new_huge_page to set the destructor */
1481 set_compound_order(page
, order
);
1482 __ClearPageReserved(page
);
1483 __SetPageHead(page
);
1484 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1486 * For gigantic hugepages allocated through bootmem at
1487 * boot, it's safer to be consistent with the not-gigantic
1488 * hugepages and clear the PG_reserved bit from all tail pages
1489 * too. Otherwse drivers using get_user_pages() to access tail
1490 * pages may get the reference counting wrong if they see
1491 * PG_reserved set on a tail page (despite the head page not
1492 * having PG_reserved set). Enforcing this consistency between
1493 * head and tail pages allows drivers to optimize away a check
1494 * on the head page when they need know if put_page() is needed
1495 * after get_user_pages().
1497 __ClearPageReserved(p
);
1498 set_page_count(p
, 0);
1499 set_compound_head(p
, page
);
1501 atomic_set(compound_mapcount_ptr(page
), -1);
1503 if (hpage_pincount_available(page
))
1504 atomic_set(compound_pincount_ptr(page
), 0);
1508 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1509 * transparent huge pages. See the PageTransHuge() documentation for more
1512 int PageHuge(struct page
*page
)
1514 if (!PageCompound(page
))
1517 page
= compound_head(page
);
1518 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1520 EXPORT_SYMBOL_GPL(PageHuge
);
1523 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1524 * normal or transparent huge pages.
1526 int PageHeadHuge(struct page
*page_head
)
1528 if (!PageHead(page_head
))
1531 return page_head
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1535 * Find address_space associated with hugetlbfs page.
1536 * Upon entry page is locked and page 'was' mapped although mapped state
1537 * could change. If necessary, use anon_vma to find vma and associated
1538 * address space. The returned mapping may be stale, but it can not be
1539 * invalid as page lock (which is held) is required to destroy mapping.
1541 static struct address_space
*_get_hugetlb_page_mapping(struct page
*hpage
)
1543 struct anon_vma
*anon_vma
;
1544 pgoff_t pgoff_start
, pgoff_end
;
1545 struct anon_vma_chain
*avc
;
1546 struct address_space
*mapping
= page_mapping(hpage
);
1548 /* Simple file based mapping */
1553 * Even anonymous hugetlbfs mappings are associated with an
1554 * underlying hugetlbfs file (see hugetlb_file_setup in mmap
1555 * code). Find a vma associated with the anonymous vma, and
1556 * use the file pointer to get address_space.
1558 anon_vma
= page_lock_anon_vma_read(hpage
);
1560 return mapping
; /* NULL */
1562 /* Use first found vma */
1563 pgoff_start
= page_to_pgoff(hpage
);
1564 pgoff_end
= pgoff_start
+ hpage_nr_pages(hpage
) - 1;
1565 anon_vma_interval_tree_foreach(avc
, &anon_vma
->rb_root
,
1566 pgoff_start
, pgoff_end
) {
1567 struct vm_area_struct
*vma
= avc
->vma
;
1569 mapping
= vma
->vm_file
->f_mapping
;
1573 anon_vma_unlock_read(anon_vma
);
1578 * Find and lock address space (mapping) in write mode.
1580 * Upon entry, the page is locked which allows us to find the mapping
1581 * even in the case of an anon page. However, locking order dictates
1582 * the i_mmap_rwsem be acquired BEFORE the page lock. This is hugetlbfs
1583 * specific. So, we first try to lock the sema while still holding the
1584 * page lock. If this works, great! If not, then we need to drop the
1585 * page lock and then acquire i_mmap_rwsem and reacquire page lock. Of
1586 * course, need to revalidate state along the way.
1588 struct address_space
*hugetlb_page_mapping_lock_write(struct page
*hpage
)
1590 struct address_space
*mapping
, *mapping2
;
1592 mapping
= _get_hugetlb_page_mapping(hpage
);
1598 * If no contention, take lock and return
1600 if (i_mmap_trylock_write(mapping
))
1604 * Must drop page lock and wait on mapping sema.
1605 * Note: Once page lock is dropped, mapping could become invalid.
1606 * As a hack, increase map count until we lock page again.
1608 atomic_inc(&hpage
->_mapcount
);
1610 i_mmap_lock_write(mapping
);
1612 atomic_add_negative(-1, &hpage
->_mapcount
);
1614 /* verify page is still mapped */
1615 if (!page_mapped(hpage
)) {
1616 i_mmap_unlock_write(mapping
);
1621 * Get address space again and verify it is the same one
1622 * we locked. If not, drop lock and retry.
1624 mapping2
= _get_hugetlb_page_mapping(hpage
);
1625 if (mapping2
!= mapping
) {
1626 i_mmap_unlock_write(mapping
);
1634 pgoff_t
__basepage_index(struct page
*page
)
1636 struct page
*page_head
= compound_head(page
);
1637 pgoff_t index
= page_index(page_head
);
1638 unsigned long compound_idx
;
1640 if (!PageHuge(page_head
))
1641 return page_index(page
);
1643 if (compound_order(page_head
) >= MAX_ORDER
)
1644 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1646 compound_idx
= page
- page_head
;
1648 return (index
<< compound_order(page_head
)) + compound_idx
;
1651 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1652 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1653 nodemask_t
*node_alloc_noretry
)
1655 int order
= huge_page_order(h
);
1657 bool alloc_try_hard
= true;
1660 * By default we always try hard to allocate the page with
1661 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1662 * a loop (to adjust global huge page counts) and previous allocation
1663 * failed, do not continue to try hard on the same node. Use the
1664 * node_alloc_noretry bitmap to manage this state information.
1666 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1667 alloc_try_hard
= false;
1668 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1670 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1671 if (nid
== NUMA_NO_NODE
)
1672 nid
= numa_mem_id();
1673 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1675 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1677 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1680 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1681 * indicates an overall state change. Clear bit so that we resume
1682 * normal 'try hard' allocations.
1684 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1685 node_clear(nid
, *node_alloc_noretry
);
1688 * If we tried hard to get a page but failed, set bit so that
1689 * subsequent attempts will not try as hard until there is an
1690 * overall state change.
1692 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1693 node_set(nid
, *node_alloc_noretry
);
1699 * Common helper to allocate a fresh hugetlb page. All specific allocators
1700 * should use this function to get new hugetlb pages
1702 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1703 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1704 nodemask_t
*node_alloc_noretry
)
1708 if (hstate_is_gigantic(h
))
1709 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1711 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1712 nid
, nmask
, node_alloc_noretry
);
1716 if (hstate_is_gigantic(h
))
1717 prep_compound_gigantic_page(page
, huge_page_order(h
));
1718 prep_new_huge_page(h
, page
, page_to_nid(page
));
1724 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1727 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1728 nodemask_t
*node_alloc_noretry
)
1732 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1734 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1735 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1736 node_alloc_noretry
);
1744 put_page(page
); /* free it into the hugepage allocator */
1750 * Free huge page from pool from next node to free.
1751 * Attempt to keep persistent huge pages more or less
1752 * balanced over allowed nodes.
1753 * Called with hugetlb_lock locked.
1755 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1761 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1763 * If we're returning unused surplus pages, only examine
1764 * nodes with surplus pages.
1766 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1767 !list_empty(&h
->hugepage_freelists
[node
])) {
1769 list_entry(h
->hugepage_freelists
[node
].next
,
1771 list_del(&page
->lru
);
1772 h
->free_huge_pages
--;
1773 h
->free_huge_pages_node
[node
]--;
1775 h
->surplus_huge_pages
--;
1776 h
->surplus_huge_pages_node
[node
]--;
1778 update_and_free_page(h
, page
);
1788 * Dissolve a given free hugepage into free buddy pages. This function does
1789 * nothing for in-use hugepages and non-hugepages.
1790 * This function returns values like below:
1792 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1793 * (allocated or reserved.)
1794 * 0: successfully dissolved free hugepages or the page is not a
1795 * hugepage (considered as already dissolved)
1797 int dissolve_free_huge_page(struct page
*page
)
1801 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1802 if (!PageHuge(page
))
1805 spin_lock(&hugetlb_lock
);
1806 if (!PageHuge(page
)) {
1811 if (!page_count(page
)) {
1812 struct page
*head
= compound_head(page
);
1813 struct hstate
*h
= page_hstate(head
);
1814 int nid
= page_to_nid(head
);
1815 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1818 * Move PageHWPoison flag from head page to the raw error page,
1819 * which makes any subpages rather than the error page reusable.
1821 if (PageHWPoison(head
) && page
!= head
) {
1822 SetPageHWPoison(page
);
1823 ClearPageHWPoison(head
);
1825 list_del(&head
->lru
);
1826 h
->free_huge_pages
--;
1827 h
->free_huge_pages_node
[nid
]--;
1828 h
->max_huge_pages
--;
1829 update_and_free_page(h
, head
);
1833 spin_unlock(&hugetlb_lock
);
1838 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1839 * make specified memory blocks removable from the system.
1840 * Note that this will dissolve a free gigantic hugepage completely, if any
1841 * part of it lies within the given range.
1842 * Also note that if dissolve_free_huge_page() returns with an error, all
1843 * free hugepages that were dissolved before that error are lost.
1845 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1851 if (!hugepages_supported())
1854 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1855 page
= pfn_to_page(pfn
);
1856 rc
= dissolve_free_huge_page(page
);
1865 * Allocates a fresh surplus page from the page allocator.
1867 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1868 int nid
, nodemask_t
*nmask
)
1870 struct page
*page
= NULL
;
1872 if (hstate_is_gigantic(h
))
1875 spin_lock(&hugetlb_lock
);
1876 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1878 spin_unlock(&hugetlb_lock
);
1880 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1884 spin_lock(&hugetlb_lock
);
1886 * We could have raced with the pool size change.
1887 * Double check that and simply deallocate the new page
1888 * if we would end up overcommiting the surpluses. Abuse
1889 * temporary page to workaround the nasty free_huge_page
1892 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1893 SetPageHugeTemporary(page
);
1894 spin_unlock(&hugetlb_lock
);
1898 h
->surplus_huge_pages
++;
1899 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1903 spin_unlock(&hugetlb_lock
);
1908 struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1909 int nid
, nodemask_t
*nmask
)
1913 if (hstate_is_gigantic(h
))
1916 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1921 * We do not account these pages as surplus because they are only
1922 * temporary and will be released properly on the last reference
1924 SetPageHugeTemporary(page
);
1930 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1933 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1934 struct vm_area_struct
*vma
, unsigned long addr
)
1937 struct mempolicy
*mpol
;
1938 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1940 nodemask_t
*nodemask
;
1942 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1943 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1944 mpol_cond_put(mpol
);
1949 /* page migration callback function */
1950 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1952 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1953 struct page
*page
= NULL
;
1955 if (nid
!= NUMA_NO_NODE
)
1956 gfp_mask
|= __GFP_THISNODE
;
1958 spin_lock(&hugetlb_lock
);
1959 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1960 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1961 spin_unlock(&hugetlb_lock
);
1964 page
= alloc_migrate_huge_page(h
, gfp_mask
, nid
, NULL
);
1969 /* page migration callback function */
1970 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1973 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1975 spin_lock(&hugetlb_lock
);
1976 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1979 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1981 spin_unlock(&hugetlb_lock
);
1985 spin_unlock(&hugetlb_lock
);
1987 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1990 /* mempolicy aware migration callback */
1991 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
1992 unsigned long address
)
1994 struct mempolicy
*mpol
;
1995 nodemask_t
*nodemask
;
2000 gfp_mask
= htlb_alloc_mask(h
);
2001 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
2002 page
= alloc_huge_page_nodemask(h
, node
, nodemask
);
2003 mpol_cond_put(mpol
);
2009 * Increase the hugetlb pool such that it can accommodate a reservation
2012 static int gather_surplus_pages(struct hstate
*h
, int delta
)
2013 __must_hold(&hugetlb_lock
)
2015 struct list_head surplus_list
;
2016 struct page
*page
, *tmp
;
2018 int needed
, allocated
;
2019 bool alloc_ok
= true;
2021 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
2023 h
->resv_huge_pages
+= delta
;
2028 INIT_LIST_HEAD(&surplus_list
);
2032 spin_unlock(&hugetlb_lock
);
2033 for (i
= 0; i
< needed
; i
++) {
2034 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
2035 NUMA_NO_NODE
, NULL
);
2040 list_add(&page
->lru
, &surplus_list
);
2046 * After retaking hugetlb_lock, we need to recalculate 'needed'
2047 * because either resv_huge_pages or free_huge_pages may have changed.
2049 spin_lock(&hugetlb_lock
);
2050 needed
= (h
->resv_huge_pages
+ delta
) -
2051 (h
->free_huge_pages
+ allocated
);
2056 * We were not able to allocate enough pages to
2057 * satisfy the entire reservation so we free what
2058 * we've allocated so far.
2063 * The surplus_list now contains _at_least_ the number of extra pages
2064 * needed to accommodate the reservation. Add the appropriate number
2065 * of pages to the hugetlb pool and free the extras back to the buddy
2066 * allocator. Commit the entire reservation here to prevent another
2067 * process from stealing the pages as they are added to the pool but
2068 * before they are reserved.
2070 needed
+= allocated
;
2071 h
->resv_huge_pages
+= delta
;
2074 /* Free the needed pages to the hugetlb pool */
2075 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
2079 * This page is now managed by the hugetlb allocator and has
2080 * no users -- drop the buddy allocator's reference.
2082 put_page_testzero(page
);
2083 VM_BUG_ON_PAGE(page_count(page
), page
);
2084 enqueue_huge_page(h
, page
);
2087 spin_unlock(&hugetlb_lock
);
2089 /* Free unnecessary surplus pages to the buddy allocator */
2090 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
2092 spin_lock(&hugetlb_lock
);
2098 * This routine has two main purposes:
2099 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2100 * in unused_resv_pages. This corresponds to the prior adjustments made
2101 * to the associated reservation map.
2102 * 2) Free any unused surplus pages that may have been allocated to satisfy
2103 * the reservation. As many as unused_resv_pages may be freed.
2105 * Called with hugetlb_lock held. However, the lock could be dropped (and
2106 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2107 * we must make sure nobody else can claim pages we are in the process of
2108 * freeing. Do this by ensuring resv_huge_page always is greater than the
2109 * number of huge pages we plan to free when dropping the lock.
2111 static void return_unused_surplus_pages(struct hstate
*h
,
2112 unsigned long unused_resv_pages
)
2114 unsigned long nr_pages
;
2116 /* Cannot return gigantic pages currently */
2117 if (hstate_is_gigantic(h
))
2121 * Part (or even all) of the reservation could have been backed
2122 * by pre-allocated pages. Only free surplus pages.
2124 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
2127 * We want to release as many surplus pages as possible, spread
2128 * evenly across all nodes with memory. Iterate across these nodes
2129 * until we can no longer free unreserved surplus pages. This occurs
2130 * when the nodes with surplus pages have no free pages.
2131 * free_pool_huge_page() will balance the the freed pages across the
2132 * on-line nodes with memory and will handle the hstate accounting.
2134 * Note that we decrement resv_huge_pages as we free the pages. If
2135 * we drop the lock, resv_huge_pages will still be sufficiently large
2136 * to cover subsequent pages we may free.
2138 while (nr_pages
--) {
2139 h
->resv_huge_pages
--;
2140 unused_resv_pages
--;
2141 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
2143 cond_resched_lock(&hugetlb_lock
);
2147 /* Fully uncommit the reservation */
2148 h
->resv_huge_pages
-= unused_resv_pages
;
2153 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2154 * are used by the huge page allocation routines to manage reservations.
2156 * vma_needs_reservation is called to determine if the huge page at addr
2157 * within the vma has an associated reservation. If a reservation is
2158 * needed, the value 1 is returned. The caller is then responsible for
2159 * managing the global reservation and subpool usage counts. After
2160 * the huge page has been allocated, vma_commit_reservation is called
2161 * to add the page to the reservation map. If the page allocation fails,
2162 * the reservation must be ended instead of committed. vma_end_reservation
2163 * is called in such cases.
2165 * In the normal case, vma_commit_reservation returns the same value
2166 * as the preceding vma_needs_reservation call. The only time this
2167 * is not the case is if a reserve map was changed between calls. It
2168 * is the responsibility of the caller to notice the difference and
2169 * take appropriate action.
2171 * vma_add_reservation is used in error paths where a reservation must
2172 * be restored when a newly allocated huge page must be freed. It is
2173 * to be called after calling vma_needs_reservation to determine if a
2174 * reservation exists.
2176 enum vma_resv_mode
{
2182 static long __vma_reservation_common(struct hstate
*h
,
2183 struct vm_area_struct
*vma
, unsigned long addr
,
2184 enum vma_resv_mode mode
)
2186 struct resv_map
*resv
;
2189 long dummy_out_regions_needed
;
2191 resv
= vma_resv_map(vma
);
2195 idx
= vma_hugecache_offset(h
, vma
, addr
);
2197 case VMA_NEEDS_RESV
:
2198 ret
= region_chg(resv
, idx
, idx
+ 1, &dummy_out_regions_needed
);
2199 /* We assume that vma_reservation_* routines always operate on
2200 * 1 page, and that adding to resv map a 1 page entry can only
2201 * ever require 1 region.
2203 VM_BUG_ON(dummy_out_regions_needed
!= 1);
2205 case VMA_COMMIT_RESV
:
2206 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2207 /* region_add calls of range 1 should never fail. */
2211 region_abort(resv
, idx
, idx
+ 1, 1);
2215 if (vma
->vm_flags
& VM_MAYSHARE
) {
2216 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2217 /* region_add calls of range 1 should never fail. */
2220 region_abort(resv
, idx
, idx
+ 1, 1);
2221 ret
= region_del(resv
, idx
, idx
+ 1);
2228 if (vma
->vm_flags
& VM_MAYSHARE
)
2230 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
2232 * In most cases, reserves always exist for private mappings.
2233 * However, a file associated with mapping could have been
2234 * hole punched or truncated after reserves were consumed.
2235 * As subsequent fault on such a range will not use reserves.
2236 * Subtle - The reserve map for private mappings has the
2237 * opposite meaning than that of shared mappings. If NO
2238 * entry is in the reserve map, it means a reservation exists.
2239 * If an entry exists in the reserve map, it means the
2240 * reservation has already been consumed. As a result, the
2241 * return value of this routine is the opposite of the
2242 * value returned from reserve map manipulation routines above.
2250 return ret
< 0 ? ret
: 0;
2253 static long vma_needs_reservation(struct hstate
*h
,
2254 struct vm_area_struct
*vma
, unsigned long addr
)
2256 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
2259 static long vma_commit_reservation(struct hstate
*h
,
2260 struct vm_area_struct
*vma
, unsigned long addr
)
2262 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
2265 static void vma_end_reservation(struct hstate
*h
,
2266 struct vm_area_struct
*vma
, unsigned long addr
)
2268 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
2271 static long vma_add_reservation(struct hstate
*h
,
2272 struct vm_area_struct
*vma
, unsigned long addr
)
2274 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
2278 * This routine is called to restore a reservation on error paths. In the
2279 * specific error paths, a huge page was allocated (via alloc_huge_page)
2280 * and is about to be freed. If a reservation for the page existed,
2281 * alloc_huge_page would have consumed the reservation and set PagePrivate
2282 * in the newly allocated page. When the page is freed via free_huge_page,
2283 * the global reservation count will be incremented if PagePrivate is set.
2284 * However, free_huge_page can not adjust the reserve map. Adjust the
2285 * reserve map here to be consistent with global reserve count adjustments
2286 * to be made by free_huge_page.
2288 static void restore_reserve_on_error(struct hstate
*h
,
2289 struct vm_area_struct
*vma
, unsigned long address
,
2292 if (unlikely(PagePrivate(page
))) {
2293 long rc
= vma_needs_reservation(h
, vma
, address
);
2295 if (unlikely(rc
< 0)) {
2297 * Rare out of memory condition in reserve map
2298 * manipulation. Clear PagePrivate so that
2299 * global reserve count will not be incremented
2300 * by free_huge_page. This will make it appear
2301 * as though the reservation for this page was
2302 * consumed. This may prevent the task from
2303 * faulting in the page at a later time. This
2304 * is better than inconsistent global huge page
2305 * accounting of reserve counts.
2307 ClearPagePrivate(page
);
2309 rc
= vma_add_reservation(h
, vma
, address
);
2310 if (unlikely(rc
< 0))
2312 * See above comment about rare out of
2315 ClearPagePrivate(page
);
2317 vma_end_reservation(h
, vma
, address
);
2321 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2322 unsigned long addr
, int avoid_reserve
)
2324 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2325 struct hstate
*h
= hstate_vma(vma
);
2327 long map_chg
, map_commit
;
2330 struct hugetlb_cgroup
*h_cg
;
2331 bool deferred_reserve
;
2333 idx
= hstate_index(h
);
2335 * Examine the region/reserve map to determine if the process
2336 * has a reservation for the page to be allocated. A return
2337 * code of zero indicates a reservation exists (no change).
2339 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2341 return ERR_PTR(-ENOMEM
);
2344 * Processes that did not create the mapping will have no
2345 * reserves as indicated by the region/reserve map. Check
2346 * that the allocation will not exceed the subpool limit.
2347 * Allocations for MAP_NORESERVE mappings also need to be
2348 * checked against any subpool limit.
2350 if (map_chg
|| avoid_reserve
) {
2351 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2353 vma_end_reservation(h
, vma
, addr
);
2354 return ERR_PTR(-ENOSPC
);
2358 * Even though there was no reservation in the region/reserve
2359 * map, there could be reservations associated with the
2360 * subpool that can be used. This would be indicated if the
2361 * return value of hugepage_subpool_get_pages() is zero.
2362 * However, if avoid_reserve is specified we still avoid even
2363 * the subpool reservations.
2369 /* If this allocation is not consuming a reservation, charge it now.
2371 deferred_reserve
= map_chg
|| avoid_reserve
|| !vma_resv_map(vma
);
2372 if (deferred_reserve
) {
2373 ret
= hugetlb_cgroup_charge_cgroup_rsvd(
2374 idx
, pages_per_huge_page(h
), &h_cg
);
2376 goto out_subpool_put
;
2379 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2381 goto out_uncharge_cgroup_reservation
;
2383 spin_lock(&hugetlb_lock
);
2385 * glb_chg is passed to indicate whether or not a page must be taken
2386 * from the global free pool (global change). gbl_chg == 0 indicates
2387 * a reservation exists for the allocation.
2389 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2391 spin_unlock(&hugetlb_lock
);
2392 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2394 goto out_uncharge_cgroup
;
2395 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2396 SetPagePrivate(page
);
2397 h
->resv_huge_pages
--;
2399 spin_lock(&hugetlb_lock
);
2400 list_move(&page
->lru
, &h
->hugepage_activelist
);
2403 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2404 /* If allocation is not consuming a reservation, also store the
2405 * hugetlb_cgroup pointer on the page.
2407 if (deferred_reserve
) {
2408 hugetlb_cgroup_commit_charge_rsvd(idx
, pages_per_huge_page(h
),
2412 spin_unlock(&hugetlb_lock
);
2414 set_page_private(page
, (unsigned long)spool
);
2416 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2417 if (unlikely(map_chg
> map_commit
)) {
2419 * The page was added to the reservation map between
2420 * vma_needs_reservation and vma_commit_reservation.
2421 * This indicates a race with hugetlb_reserve_pages.
2422 * Adjust for the subpool count incremented above AND
2423 * in hugetlb_reserve_pages for the same page. Also,
2424 * the reservation count added in hugetlb_reserve_pages
2425 * no longer applies.
2429 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2430 hugetlb_acct_memory(h
, -rsv_adjust
);
2434 out_uncharge_cgroup
:
2435 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2436 out_uncharge_cgroup_reservation
:
2437 if (deferred_reserve
)
2438 hugetlb_cgroup_uncharge_cgroup_rsvd(idx
, pages_per_huge_page(h
),
2441 if (map_chg
|| avoid_reserve
)
2442 hugepage_subpool_put_pages(spool
, 1);
2443 vma_end_reservation(h
, vma
, addr
);
2444 return ERR_PTR(-ENOSPC
);
2447 int alloc_bootmem_huge_page(struct hstate
*h
)
2448 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2449 int __alloc_bootmem_huge_page(struct hstate
*h
)
2451 struct huge_bootmem_page
*m
;
2454 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2457 addr
= memblock_alloc_try_nid_raw(
2458 huge_page_size(h
), huge_page_size(h
),
2459 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2462 * Use the beginning of the huge page to store the
2463 * huge_bootmem_page struct (until gather_bootmem
2464 * puts them into the mem_map).
2473 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2474 /* Put them into a private list first because mem_map is not up yet */
2475 INIT_LIST_HEAD(&m
->list
);
2476 list_add(&m
->list
, &huge_boot_pages
);
2481 static void __init
prep_compound_huge_page(struct page
*page
,
2484 if (unlikely(order
> (MAX_ORDER
- 1)))
2485 prep_compound_gigantic_page(page
, order
);
2487 prep_compound_page(page
, order
);
2490 /* Put bootmem huge pages into the standard lists after mem_map is up */
2491 static void __init
gather_bootmem_prealloc(void)
2493 struct huge_bootmem_page
*m
;
2495 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2496 struct page
*page
= virt_to_page(m
);
2497 struct hstate
*h
= m
->hstate
;
2499 WARN_ON(page_count(page
) != 1);
2500 prep_compound_huge_page(page
, h
->order
);
2501 WARN_ON(PageReserved(page
));
2502 prep_new_huge_page(h
, page
, page_to_nid(page
));
2503 put_page(page
); /* free it into the hugepage allocator */
2506 * If we had gigantic hugepages allocated at boot time, we need
2507 * to restore the 'stolen' pages to totalram_pages in order to
2508 * fix confusing memory reports from free(1) and another
2509 * side-effects, like CommitLimit going negative.
2511 if (hstate_is_gigantic(h
))
2512 adjust_managed_page_count(page
, 1 << h
->order
);
2517 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2520 nodemask_t
*node_alloc_noretry
;
2522 if (!hstate_is_gigantic(h
)) {
2524 * Bit mask controlling how hard we retry per-node allocations.
2525 * Ignore errors as lower level routines can deal with
2526 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2527 * time, we are likely in bigger trouble.
2529 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2532 /* allocations done at boot time */
2533 node_alloc_noretry
= NULL
;
2536 /* bit mask controlling how hard we retry per-node allocations */
2537 if (node_alloc_noretry
)
2538 nodes_clear(*node_alloc_noretry
);
2540 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2541 if (hstate_is_gigantic(h
)) {
2542 if (!alloc_bootmem_huge_page(h
))
2544 } else if (!alloc_pool_huge_page(h
,
2545 &node_states
[N_MEMORY
],
2546 node_alloc_noretry
))
2550 if (i
< h
->max_huge_pages
) {
2553 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2554 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2555 h
->max_huge_pages
, buf
, i
);
2556 h
->max_huge_pages
= i
;
2559 kfree(node_alloc_noretry
);
2562 static void __init
hugetlb_init_hstates(void)
2566 for_each_hstate(h
) {
2567 if (minimum_order
> huge_page_order(h
))
2568 minimum_order
= huge_page_order(h
);
2570 /* oversize hugepages were init'ed in early boot */
2571 if (!hstate_is_gigantic(h
))
2572 hugetlb_hstate_alloc_pages(h
);
2574 VM_BUG_ON(minimum_order
== UINT_MAX
);
2577 static void __init
report_hugepages(void)
2581 for_each_hstate(h
) {
2584 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2585 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2586 buf
, h
->free_huge_pages
);
2590 #ifdef CONFIG_HIGHMEM
2591 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2592 nodemask_t
*nodes_allowed
)
2596 if (hstate_is_gigantic(h
))
2599 for_each_node_mask(i
, *nodes_allowed
) {
2600 struct page
*page
, *next
;
2601 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2602 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2603 if (count
>= h
->nr_huge_pages
)
2605 if (PageHighMem(page
))
2607 list_del(&page
->lru
);
2608 update_and_free_page(h
, page
);
2609 h
->free_huge_pages
--;
2610 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2615 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2616 nodemask_t
*nodes_allowed
)
2622 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2623 * balanced by operating on them in a round-robin fashion.
2624 * Returns 1 if an adjustment was made.
2626 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2631 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2634 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2635 if (h
->surplus_huge_pages_node
[node
])
2639 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2640 if (h
->surplus_huge_pages_node
[node
] <
2641 h
->nr_huge_pages_node
[node
])
2648 h
->surplus_huge_pages
+= delta
;
2649 h
->surplus_huge_pages_node
[node
] += delta
;
2653 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2654 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2655 nodemask_t
*nodes_allowed
)
2657 unsigned long min_count
, ret
;
2658 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2661 * Bit mask controlling how hard we retry per-node allocations.
2662 * If we can not allocate the bit mask, do not attempt to allocate
2663 * the requested huge pages.
2665 if (node_alloc_noretry
)
2666 nodes_clear(*node_alloc_noretry
);
2670 spin_lock(&hugetlb_lock
);
2673 * Check for a node specific request.
2674 * Changing node specific huge page count may require a corresponding
2675 * change to the global count. In any case, the passed node mask
2676 * (nodes_allowed) will restrict alloc/free to the specified node.
2678 if (nid
!= NUMA_NO_NODE
) {
2679 unsigned long old_count
= count
;
2681 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2683 * User may have specified a large count value which caused the
2684 * above calculation to overflow. In this case, they wanted
2685 * to allocate as many huge pages as possible. Set count to
2686 * largest possible value to align with their intention.
2688 if (count
< old_count
)
2693 * Gigantic pages runtime allocation depend on the capability for large
2694 * page range allocation.
2695 * If the system does not provide this feature, return an error when
2696 * the user tries to allocate gigantic pages but let the user free the
2697 * boottime allocated gigantic pages.
2699 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2700 if (count
> persistent_huge_pages(h
)) {
2701 spin_unlock(&hugetlb_lock
);
2702 NODEMASK_FREE(node_alloc_noretry
);
2705 /* Fall through to decrease pool */
2709 * Increase the pool size
2710 * First take pages out of surplus state. Then make up the
2711 * remaining difference by allocating fresh huge pages.
2713 * We might race with alloc_surplus_huge_page() here and be unable
2714 * to convert a surplus huge page to a normal huge page. That is
2715 * not critical, though, it just means the overall size of the
2716 * pool might be one hugepage larger than it needs to be, but
2717 * within all the constraints specified by the sysctls.
2719 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2720 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2724 while (count
> persistent_huge_pages(h
)) {
2726 * If this allocation races such that we no longer need the
2727 * page, free_huge_page will handle it by freeing the page
2728 * and reducing the surplus.
2730 spin_unlock(&hugetlb_lock
);
2732 /* yield cpu to avoid soft lockup */
2735 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2736 node_alloc_noretry
);
2737 spin_lock(&hugetlb_lock
);
2741 /* Bail for signals. Probably ctrl-c from user */
2742 if (signal_pending(current
))
2747 * Decrease the pool size
2748 * First return free pages to the buddy allocator (being careful
2749 * to keep enough around to satisfy reservations). Then place
2750 * pages into surplus state as needed so the pool will shrink
2751 * to the desired size as pages become free.
2753 * By placing pages into the surplus state independent of the
2754 * overcommit value, we are allowing the surplus pool size to
2755 * exceed overcommit. There are few sane options here. Since
2756 * alloc_surplus_huge_page() is checking the global counter,
2757 * though, we'll note that we're not allowed to exceed surplus
2758 * and won't grow the pool anywhere else. Not until one of the
2759 * sysctls are changed, or the surplus pages go out of use.
2761 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2762 min_count
= max(count
, min_count
);
2763 try_to_free_low(h
, min_count
, nodes_allowed
);
2764 while (min_count
< persistent_huge_pages(h
)) {
2765 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2767 cond_resched_lock(&hugetlb_lock
);
2769 while (count
< persistent_huge_pages(h
)) {
2770 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2774 h
->max_huge_pages
= persistent_huge_pages(h
);
2775 spin_unlock(&hugetlb_lock
);
2777 NODEMASK_FREE(node_alloc_noretry
);
2782 #define HSTATE_ATTR_RO(_name) \
2783 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2785 #define HSTATE_ATTR(_name) \
2786 static struct kobj_attribute _name##_attr = \
2787 __ATTR(_name, 0644, _name##_show, _name##_store)
2789 static struct kobject
*hugepages_kobj
;
2790 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2792 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2794 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2798 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2799 if (hstate_kobjs
[i
] == kobj
) {
2801 *nidp
= NUMA_NO_NODE
;
2805 return kobj_to_node_hstate(kobj
, nidp
);
2808 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2809 struct kobj_attribute
*attr
, char *buf
)
2812 unsigned long nr_huge_pages
;
2815 h
= kobj_to_hstate(kobj
, &nid
);
2816 if (nid
== NUMA_NO_NODE
)
2817 nr_huge_pages
= h
->nr_huge_pages
;
2819 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2821 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2824 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2825 struct hstate
*h
, int nid
,
2826 unsigned long count
, size_t len
)
2829 nodemask_t nodes_allowed
, *n_mask
;
2831 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2834 if (nid
== NUMA_NO_NODE
) {
2836 * global hstate attribute
2838 if (!(obey_mempolicy
&&
2839 init_nodemask_of_mempolicy(&nodes_allowed
)))
2840 n_mask
= &node_states
[N_MEMORY
];
2842 n_mask
= &nodes_allowed
;
2845 * Node specific request. count adjustment happens in
2846 * set_max_huge_pages() after acquiring hugetlb_lock.
2848 init_nodemask_of_node(&nodes_allowed
, nid
);
2849 n_mask
= &nodes_allowed
;
2852 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2854 return err
? err
: len
;
2857 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2858 struct kobject
*kobj
, const char *buf
,
2862 unsigned long count
;
2866 err
= kstrtoul(buf
, 10, &count
);
2870 h
= kobj_to_hstate(kobj
, &nid
);
2871 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2874 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2875 struct kobj_attribute
*attr
, char *buf
)
2877 return nr_hugepages_show_common(kobj
, attr
, buf
);
2880 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2881 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2883 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2885 HSTATE_ATTR(nr_hugepages
);
2890 * hstate attribute for optionally mempolicy-based constraint on persistent
2891 * huge page alloc/free.
2893 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2894 struct kobj_attribute
*attr
, char *buf
)
2896 return nr_hugepages_show_common(kobj
, attr
, buf
);
2899 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2900 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2902 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2904 HSTATE_ATTR(nr_hugepages_mempolicy
);
2908 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2909 struct kobj_attribute
*attr
, char *buf
)
2911 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2912 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2915 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2916 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2919 unsigned long input
;
2920 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2922 if (hstate_is_gigantic(h
))
2925 err
= kstrtoul(buf
, 10, &input
);
2929 spin_lock(&hugetlb_lock
);
2930 h
->nr_overcommit_huge_pages
= input
;
2931 spin_unlock(&hugetlb_lock
);
2935 HSTATE_ATTR(nr_overcommit_hugepages
);
2937 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2938 struct kobj_attribute
*attr
, char *buf
)
2941 unsigned long free_huge_pages
;
2944 h
= kobj_to_hstate(kobj
, &nid
);
2945 if (nid
== NUMA_NO_NODE
)
2946 free_huge_pages
= h
->free_huge_pages
;
2948 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2950 return sprintf(buf
, "%lu\n", free_huge_pages
);
2952 HSTATE_ATTR_RO(free_hugepages
);
2954 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2955 struct kobj_attribute
*attr
, char *buf
)
2957 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2958 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2960 HSTATE_ATTR_RO(resv_hugepages
);
2962 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2963 struct kobj_attribute
*attr
, char *buf
)
2966 unsigned long surplus_huge_pages
;
2969 h
= kobj_to_hstate(kobj
, &nid
);
2970 if (nid
== NUMA_NO_NODE
)
2971 surplus_huge_pages
= h
->surplus_huge_pages
;
2973 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2975 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2977 HSTATE_ATTR_RO(surplus_hugepages
);
2979 static struct attribute
*hstate_attrs
[] = {
2980 &nr_hugepages_attr
.attr
,
2981 &nr_overcommit_hugepages_attr
.attr
,
2982 &free_hugepages_attr
.attr
,
2983 &resv_hugepages_attr
.attr
,
2984 &surplus_hugepages_attr
.attr
,
2986 &nr_hugepages_mempolicy_attr
.attr
,
2991 static const struct attribute_group hstate_attr_group
= {
2992 .attrs
= hstate_attrs
,
2995 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2996 struct kobject
**hstate_kobjs
,
2997 const struct attribute_group
*hstate_attr_group
)
3000 int hi
= hstate_index(h
);
3002 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
3003 if (!hstate_kobjs
[hi
])
3006 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
3008 kobject_put(hstate_kobjs
[hi
]);
3013 static void __init
hugetlb_sysfs_init(void)
3018 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
3019 if (!hugepages_kobj
)
3022 for_each_hstate(h
) {
3023 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
3024 hstate_kobjs
, &hstate_attr_group
);
3026 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
3033 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3034 * with node devices in node_devices[] using a parallel array. The array
3035 * index of a node device or _hstate == node id.
3036 * This is here to avoid any static dependency of the node device driver, in
3037 * the base kernel, on the hugetlb module.
3039 struct node_hstate
{
3040 struct kobject
*hugepages_kobj
;
3041 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
3043 static struct node_hstate node_hstates
[MAX_NUMNODES
];
3046 * A subset of global hstate attributes for node devices
3048 static struct attribute
*per_node_hstate_attrs
[] = {
3049 &nr_hugepages_attr
.attr
,
3050 &free_hugepages_attr
.attr
,
3051 &surplus_hugepages_attr
.attr
,
3055 static const struct attribute_group per_node_hstate_attr_group
= {
3056 .attrs
= per_node_hstate_attrs
,
3060 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3061 * Returns node id via non-NULL nidp.
3063 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3067 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
3068 struct node_hstate
*nhs
= &node_hstates
[nid
];
3070 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
3071 if (nhs
->hstate_kobjs
[i
] == kobj
) {
3083 * Unregister hstate attributes from a single node device.
3084 * No-op if no hstate attributes attached.
3086 static void hugetlb_unregister_node(struct node
*node
)
3089 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3091 if (!nhs
->hugepages_kobj
)
3092 return; /* no hstate attributes */
3094 for_each_hstate(h
) {
3095 int idx
= hstate_index(h
);
3096 if (nhs
->hstate_kobjs
[idx
]) {
3097 kobject_put(nhs
->hstate_kobjs
[idx
]);
3098 nhs
->hstate_kobjs
[idx
] = NULL
;
3102 kobject_put(nhs
->hugepages_kobj
);
3103 nhs
->hugepages_kobj
= NULL
;
3108 * Register hstate attributes for a single node device.
3109 * No-op if attributes already registered.
3111 static void hugetlb_register_node(struct node
*node
)
3114 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3117 if (nhs
->hugepages_kobj
)
3118 return; /* already allocated */
3120 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
3122 if (!nhs
->hugepages_kobj
)
3125 for_each_hstate(h
) {
3126 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
3128 &per_node_hstate_attr_group
);
3130 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
3131 h
->name
, node
->dev
.id
);
3132 hugetlb_unregister_node(node
);
3139 * hugetlb init time: register hstate attributes for all registered node
3140 * devices of nodes that have memory. All on-line nodes should have
3141 * registered their associated device by this time.
3143 static void __init
hugetlb_register_all_nodes(void)
3147 for_each_node_state(nid
, N_MEMORY
) {
3148 struct node
*node
= node_devices
[nid
];
3149 if (node
->dev
.id
== nid
)
3150 hugetlb_register_node(node
);
3154 * Let the node device driver know we're here so it can
3155 * [un]register hstate attributes on node hotplug.
3157 register_hugetlbfs_with_node(hugetlb_register_node
,
3158 hugetlb_unregister_node
);
3160 #else /* !CONFIG_NUMA */
3162 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3170 static void hugetlb_register_all_nodes(void) { }
3174 static int __init
hugetlb_init(void)
3178 if (!hugepages_supported())
3181 if (!size_to_hstate(default_hstate_size
)) {
3182 if (default_hstate_size
!= 0) {
3183 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
3184 default_hstate_size
, HPAGE_SIZE
);
3187 default_hstate_size
= HPAGE_SIZE
;
3188 if (!size_to_hstate(default_hstate_size
))
3189 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
3191 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
3192 if (default_hstate_max_huge_pages
) {
3193 if (!default_hstate
.max_huge_pages
)
3194 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
3197 hugetlb_init_hstates();
3198 gather_bootmem_prealloc();
3201 hugetlb_sysfs_init();
3202 hugetlb_register_all_nodes();
3203 hugetlb_cgroup_file_init();
3206 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
3208 num_fault_mutexes
= 1;
3210 hugetlb_fault_mutex_table
=
3211 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
3213 BUG_ON(!hugetlb_fault_mutex_table
);
3215 for (i
= 0; i
< num_fault_mutexes
; i
++)
3216 mutex_init(&hugetlb_fault_mutex_table
[i
]);
3219 subsys_initcall(hugetlb_init
);
3221 /* Should be called on processing a hugepagesz=... option */
3222 void __init
hugetlb_bad_size(void)
3224 parsed_valid_hugepagesz
= false;
3227 void __init
hugetlb_add_hstate(unsigned int order
)
3232 if (size_to_hstate(PAGE_SIZE
<< order
)) {
3233 pr_warn("hugepagesz= specified twice, ignoring\n");
3236 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
3238 h
= &hstates
[hugetlb_max_hstate
++];
3240 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
3241 h
->nr_huge_pages
= 0;
3242 h
->free_huge_pages
= 0;
3243 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
3244 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
3245 INIT_LIST_HEAD(&h
->hugepage_activelist
);
3246 h
->next_nid_to_alloc
= first_memory_node
;
3247 h
->next_nid_to_free
= first_memory_node
;
3248 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
3249 huge_page_size(h
)/1024);
3254 static int __init
hugetlb_nrpages_setup(char *s
)
3257 static unsigned long *last_mhp
;
3259 if (!parsed_valid_hugepagesz
) {
3260 pr_warn("hugepages = %s preceded by "
3261 "an unsupported hugepagesz, ignoring\n", s
);
3262 parsed_valid_hugepagesz
= true;
3266 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
3267 * so this hugepages= parameter goes to the "default hstate".
3269 else if (!hugetlb_max_hstate
)
3270 mhp
= &default_hstate_max_huge_pages
;
3272 mhp
= &parsed_hstate
->max_huge_pages
;
3274 if (mhp
== last_mhp
) {
3275 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
3279 if (sscanf(s
, "%lu", mhp
) <= 0)
3283 * Global state is always initialized later in hugetlb_init.
3284 * But we need to allocate >= MAX_ORDER hstates here early to still
3285 * use the bootmem allocator.
3287 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
3288 hugetlb_hstate_alloc_pages(parsed_hstate
);
3294 __setup("hugepages=", hugetlb_nrpages_setup
);
3296 static int __init
hugetlb_default_setup(char *s
)
3298 default_hstate_size
= memparse(s
, &s
);
3301 __setup("default_hugepagesz=", hugetlb_default_setup
);
3303 static unsigned int cpuset_mems_nr(unsigned int *array
)
3306 unsigned int nr
= 0;
3308 for_each_node_mask(node
, cpuset_current_mems_allowed
)
3314 #ifdef CONFIG_SYSCTL
3315 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
3316 struct ctl_table
*table
, int write
,
3317 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3319 struct hstate
*h
= &default_hstate
;
3320 unsigned long tmp
= h
->max_huge_pages
;
3323 if (!hugepages_supported())
3327 table
->maxlen
= sizeof(unsigned long);
3328 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3333 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
3334 NUMA_NO_NODE
, tmp
, *length
);
3339 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
3340 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3343 return hugetlb_sysctl_handler_common(false, table
, write
,
3344 buffer
, length
, ppos
);
3348 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3349 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3351 return hugetlb_sysctl_handler_common(true, table
, write
,
3352 buffer
, length
, ppos
);
3354 #endif /* CONFIG_NUMA */
3356 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3357 void __user
*buffer
,
3358 size_t *length
, loff_t
*ppos
)
3360 struct hstate
*h
= &default_hstate
;
3364 if (!hugepages_supported())
3367 tmp
= h
->nr_overcommit_huge_pages
;
3369 if (write
&& hstate_is_gigantic(h
))
3373 table
->maxlen
= sizeof(unsigned long);
3374 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3379 spin_lock(&hugetlb_lock
);
3380 h
->nr_overcommit_huge_pages
= tmp
;
3381 spin_unlock(&hugetlb_lock
);
3387 #endif /* CONFIG_SYSCTL */
3389 void hugetlb_report_meminfo(struct seq_file
*m
)
3392 unsigned long total
= 0;
3394 if (!hugepages_supported())
3397 for_each_hstate(h
) {
3398 unsigned long count
= h
->nr_huge_pages
;
3400 total
+= (PAGE_SIZE
<< huge_page_order(h
)) * count
;
3402 if (h
== &default_hstate
)
3404 "HugePages_Total: %5lu\n"
3405 "HugePages_Free: %5lu\n"
3406 "HugePages_Rsvd: %5lu\n"
3407 "HugePages_Surp: %5lu\n"
3408 "Hugepagesize: %8lu kB\n",
3412 h
->surplus_huge_pages
,
3413 (PAGE_SIZE
<< huge_page_order(h
)) / 1024);
3416 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ 1024);
3419 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3421 struct hstate
*h
= &default_hstate
;
3422 if (!hugepages_supported())
3425 "Node %d HugePages_Total: %5u\n"
3426 "Node %d HugePages_Free: %5u\n"
3427 "Node %d HugePages_Surp: %5u\n",
3428 nid
, h
->nr_huge_pages_node
[nid
],
3429 nid
, h
->free_huge_pages_node
[nid
],
3430 nid
, h
->surplus_huge_pages_node
[nid
]);
3433 void hugetlb_show_meminfo(void)
3438 if (!hugepages_supported())
3441 for_each_node_state(nid
, N_MEMORY
)
3443 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3445 h
->nr_huge_pages_node
[nid
],
3446 h
->free_huge_pages_node
[nid
],
3447 h
->surplus_huge_pages_node
[nid
],
3448 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3451 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3453 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3454 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3457 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3458 unsigned long hugetlb_total_pages(void)
3461 unsigned long nr_total_pages
= 0;
3464 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3465 return nr_total_pages
;
3468 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3472 spin_lock(&hugetlb_lock
);
3474 * When cpuset is configured, it breaks the strict hugetlb page
3475 * reservation as the accounting is done on a global variable. Such
3476 * reservation is completely rubbish in the presence of cpuset because
3477 * the reservation is not checked against page availability for the
3478 * current cpuset. Application can still potentially OOM'ed by kernel
3479 * with lack of free htlb page in cpuset that the task is in.
3480 * Attempt to enforce strict accounting with cpuset is almost
3481 * impossible (or too ugly) because cpuset is too fluid that
3482 * task or memory node can be dynamically moved between cpusets.
3484 * The change of semantics for shared hugetlb mapping with cpuset is
3485 * undesirable. However, in order to preserve some of the semantics,
3486 * we fall back to check against current free page availability as
3487 * a best attempt and hopefully to minimize the impact of changing
3488 * semantics that cpuset has.
3491 if (gather_surplus_pages(h
, delta
) < 0)
3494 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3495 return_unused_surplus_pages(h
, delta
);
3502 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3505 spin_unlock(&hugetlb_lock
);
3509 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3511 struct resv_map
*resv
= vma_resv_map(vma
);
3514 * This new VMA should share its siblings reservation map if present.
3515 * The VMA will only ever have a valid reservation map pointer where
3516 * it is being copied for another still existing VMA. As that VMA
3517 * has a reference to the reservation map it cannot disappear until
3518 * after this open call completes. It is therefore safe to take a
3519 * new reference here without additional locking.
3521 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3522 kref_get(&resv
->refs
);
3525 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3527 struct hstate
*h
= hstate_vma(vma
);
3528 struct resv_map
*resv
= vma_resv_map(vma
);
3529 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3530 unsigned long reserve
, start
, end
;
3533 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3536 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3537 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3539 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3540 hugetlb_cgroup_uncharge_counter(resv
, start
, end
);
3543 * Decrement reserve counts. The global reserve count may be
3544 * adjusted if the subpool has a minimum size.
3546 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3547 hugetlb_acct_memory(h
, -gbl_reserve
);
3550 kref_put(&resv
->refs
, resv_map_release
);
3553 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3555 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3560 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3562 struct hstate
*hstate
= hstate_vma(vma
);
3564 return 1UL << huge_page_shift(hstate
);
3568 * We cannot handle pagefaults against hugetlb pages at all. They cause
3569 * handle_mm_fault() to try to instantiate regular-sized pages in the
3570 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3573 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3580 * When a new function is introduced to vm_operations_struct and added
3581 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3582 * This is because under System V memory model, mappings created via
3583 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3584 * their original vm_ops are overwritten with shm_vm_ops.
3586 const struct vm_operations_struct hugetlb_vm_ops
= {
3587 .fault
= hugetlb_vm_op_fault
,
3588 .open
= hugetlb_vm_op_open
,
3589 .close
= hugetlb_vm_op_close
,
3590 .split
= hugetlb_vm_op_split
,
3591 .pagesize
= hugetlb_vm_op_pagesize
,
3594 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3600 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3601 vma
->vm_page_prot
)));
3603 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3604 vma
->vm_page_prot
));
3606 entry
= pte_mkyoung(entry
);
3607 entry
= pte_mkhuge(entry
);
3608 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3613 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3614 unsigned long address
, pte_t
*ptep
)
3618 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3619 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3620 update_mmu_cache(vma
, address
, ptep
);
3623 bool is_hugetlb_entry_migration(pte_t pte
)
3627 if (huge_pte_none(pte
) || pte_present(pte
))
3629 swp
= pte_to_swp_entry(pte
);
3630 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3636 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3640 if (huge_pte_none(pte
) || pte_present(pte
))
3642 swp
= pte_to_swp_entry(pte
);
3643 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3649 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3650 struct vm_area_struct
*vma
)
3652 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3653 struct page
*ptepage
;
3656 struct hstate
*h
= hstate_vma(vma
);
3657 unsigned long sz
= huge_page_size(h
);
3658 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3659 struct mmu_notifier_range range
;
3662 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3665 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3668 mmu_notifier_invalidate_range_start(&range
);
3671 * For shared mappings i_mmap_rwsem must be held to call
3672 * huge_pte_alloc, otherwise the returned ptep could go
3673 * away if part of a shared pmd and another thread calls
3676 i_mmap_lock_read(mapping
);
3679 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3680 spinlock_t
*src_ptl
, *dst_ptl
;
3681 src_pte
= huge_pte_offset(src
, addr
, sz
);
3684 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3691 * If the pagetables are shared don't copy or take references.
3692 * dst_pte == src_pte is the common case of src/dest sharing.
3694 * However, src could have 'unshared' and dst shares with
3695 * another vma. If dst_pte !none, this implies sharing.
3696 * Check here before taking page table lock, and once again
3697 * after taking the lock below.
3699 dst_entry
= huge_ptep_get(dst_pte
);
3700 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3703 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3704 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3705 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3706 entry
= huge_ptep_get(src_pte
);
3707 dst_entry
= huge_ptep_get(dst_pte
);
3708 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3710 * Skip if src entry none. Also, skip in the
3711 * unlikely case dst entry !none as this implies
3712 * sharing with another vma.
3715 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3716 is_hugetlb_entry_hwpoisoned(entry
))) {
3717 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3719 if (is_write_migration_entry(swp_entry
) && cow
) {
3721 * COW mappings require pages in both
3722 * parent and child to be set to read.
3724 make_migration_entry_read(&swp_entry
);
3725 entry
= swp_entry_to_pte(swp_entry
);
3726 set_huge_swap_pte_at(src
, addr
, src_pte
,
3729 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3733 * No need to notify as we are downgrading page
3734 * table protection not changing it to point
3737 * See Documentation/vm/mmu_notifier.rst
3739 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3741 entry
= huge_ptep_get(src_pte
);
3742 ptepage
= pte_page(entry
);
3744 page_dup_rmap(ptepage
, true);
3745 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3746 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3748 spin_unlock(src_ptl
);
3749 spin_unlock(dst_ptl
);
3753 mmu_notifier_invalidate_range_end(&range
);
3755 i_mmap_unlock_read(mapping
);
3760 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3761 unsigned long start
, unsigned long end
,
3762 struct page
*ref_page
)
3764 struct mm_struct
*mm
= vma
->vm_mm
;
3765 unsigned long address
;
3770 struct hstate
*h
= hstate_vma(vma
);
3771 unsigned long sz
= huge_page_size(h
);
3772 struct mmu_notifier_range range
;
3774 WARN_ON(!is_vm_hugetlb_page(vma
));
3775 BUG_ON(start
& ~huge_page_mask(h
));
3776 BUG_ON(end
& ~huge_page_mask(h
));
3779 * This is a hugetlb vma, all the pte entries should point
3782 tlb_change_page_size(tlb
, sz
);
3783 tlb_start_vma(tlb
, vma
);
3786 * If sharing possible, alert mmu notifiers of worst case.
3788 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3790 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3791 mmu_notifier_invalidate_range_start(&range
);
3793 for (; address
< end
; address
+= sz
) {
3794 ptep
= huge_pte_offset(mm
, address
, sz
);
3798 ptl
= huge_pte_lock(h
, mm
, ptep
);
3799 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3802 * We just unmapped a page of PMDs by clearing a PUD.
3803 * The caller's TLB flush range should cover this area.
3808 pte
= huge_ptep_get(ptep
);
3809 if (huge_pte_none(pte
)) {
3815 * Migrating hugepage or HWPoisoned hugepage is already
3816 * unmapped and its refcount is dropped, so just clear pte here.
3818 if (unlikely(!pte_present(pte
))) {
3819 huge_pte_clear(mm
, address
, ptep
, sz
);
3824 page
= pte_page(pte
);
3826 * If a reference page is supplied, it is because a specific
3827 * page is being unmapped, not a range. Ensure the page we
3828 * are about to unmap is the actual page of interest.
3831 if (page
!= ref_page
) {
3836 * Mark the VMA as having unmapped its page so that
3837 * future faults in this VMA will fail rather than
3838 * looking like data was lost
3840 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3843 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3844 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3845 if (huge_pte_dirty(pte
))
3846 set_page_dirty(page
);
3848 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3849 page_remove_rmap(page
, true);
3852 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3854 * Bail out after unmapping reference page if supplied
3859 mmu_notifier_invalidate_range_end(&range
);
3860 tlb_end_vma(tlb
, vma
);
3863 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3864 struct vm_area_struct
*vma
, unsigned long start
,
3865 unsigned long end
, struct page
*ref_page
)
3867 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3870 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3871 * test will fail on a vma being torn down, and not grab a page table
3872 * on its way out. We're lucky that the flag has such an appropriate
3873 * name, and can in fact be safely cleared here. We could clear it
3874 * before the __unmap_hugepage_range above, but all that's necessary
3875 * is to clear it before releasing the i_mmap_rwsem. This works
3876 * because in the context this is called, the VMA is about to be
3877 * destroyed and the i_mmap_rwsem is held.
3879 vma
->vm_flags
&= ~VM_MAYSHARE
;
3882 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3883 unsigned long end
, struct page
*ref_page
)
3885 struct mm_struct
*mm
;
3886 struct mmu_gather tlb
;
3887 unsigned long tlb_start
= start
;
3888 unsigned long tlb_end
= end
;
3891 * If shared PMDs were possibly used within this vma range, adjust
3892 * start/end for worst case tlb flushing.
3893 * Note that we can not be sure if PMDs are shared until we try to
3894 * unmap pages. However, we want to make sure TLB flushing covers
3895 * the largest possible range.
3897 adjust_range_if_pmd_sharing_possible(vma
, &tlb_start
, &tlb_end
);
3901 tlb_gather_mmu(&tlb
, mm
, tlb_start
, tlb_end
);
3902 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3903 tlb_finish_mmu(&tlb
, tlb_start
, tlb_end
);
3907 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3908 * mappping it owns the reserve page for. The intention is to unmap the page
3909 * from other VMAs and let the children be SIGKILLed if they are faulting the
3912 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3913 struct page
*page
, unsigned long address
)
3915 struct hstate
*h
= hstate_vma(vma
);
3916 struct vm_area_struct
*iter_vma
;
3917 struct address_space
*mapping
;
3921 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3922 * from page cache lookup which is in HPAGE_SIZE units.
3924 address
= address
& huge_page_mask(h
);
3925 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3927 mapping
= vma
->vm_file
->f_mapping
;
3930 * Take the mapping lock for the duration of the table walk. As
3931 * this mapping should be shared between all the VMAs,
3932 * __unmap_hugepage_range() is called as the lock is already held
3934 i_mmap_lock_write(mapping
);
3935 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3936 /* Do not unmap the current VMA */
3937 if (iter_vma
== vma
)
3941 * Shared VMAs have their own reserves and do not affect
3942 * MAP_PRIVATE accounting but it is possible that a shared
3943 * VMA is using the same page so check and skip such VMAs.
3945 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3949 * Unmap the page from other VMAs without their own reserves.
3950 * They get marked to be SIGKILLed if they fault in these
3951 * areas. This is because a future no-page fault on this VMA
3952 * could insert a zeroed page instead of the data existing
3953 * from the time of fork. This would look like data corruption
3955 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3956 unmap_hugepage_range(iter_vma
, address
,
3957 address
+ huge_page_size(h
), page
);
3959 i_mmap_unlock_write(mapping
);
3963 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3964 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3965 * cannot race with other handlers or page migration.
3966 * Keep the pte_same checks anyway to make transition from the mutex easier.
3968 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3969 unsigned long address
, pte_t
*ptep
,
3970 struct page
*pagecache_page
, spinlock_t
*ptl
)
3973 struct hstate
*h
= hstate_vma(vma
);
3974 struct page
*old_page
, *new_page
;
3975 int outside_reserve
= 0;
3977 unsigned long haddr
= address
& huge_page_mask(h
);
3978 struct mmu_notifier_range range
;
3980 pte
= huge_ptep_get(ptep
);
3981 old_page
= pte_page(pte
);
3984 /* If no-one else is actually using this page, avoid the copy
3985 * and just make the page writable */
3986 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3987 page_move_anon_rmap(old_page
, vma
);
3988 set_huge_ptep_writable(vma
, haddr
, ptep
);
3993 * If the process that created a MAP_PRIVATE mapping is about to
3994 * perform a COW due to a shared page count, attempt to satisfy
3995 * the allocation without using the existing reserves. The pagecache
3996 * page is used to determine if the reserve at this address was
3997 * consumed or not. If reserves were used, a partial faulted mapping
3998 * at the time of fork() could consume its reserves on COW instead
3999 * of the full address range.
4001 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
4002 old_page
!= pagecache_page
)
4003 outside_reserve
= 1;
4008 * Drop page table lock as buddy allocator may be called. It will
4009 * be acquired again before returning to the caller, as expected.
4012 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
4014 if (IS_ERR(new_page
)) {
4016 * If a process owning a MAP_PRIVATE mapping fails to COW,
4017 * it is due to references held by a child and an insufficient
4018 * huge page pool. To guarantee the original mappers
4019 * reliability, unmap the page from child processes. The child
4020 * may get SIGKILLed if it later faults.
4022 if (outside_reserve
) {
4024 BUG_ON(huge_pte_none(pte
));
4025 unmap_ref_private(mm
, vma
, old_page
, haddr
);
4026 BUG_ON(huge_pte_none(pte
));
4028 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4030 pte_same(huge_ptep_get(ptep
), pte
)))
4031 goto retry_avoidcopy
;
4033 * race occurs while re-acquiring page table
4034 * lock, and our job is done.
4039 ret
= vmf_error(PTR_ERR(new_page
));
4040 goto out_release_old
;
4044 * When the original hugepage is shared one, it does not have
4045 * anon_vma prepared.
4047 if (unlikely(anon_vma_prepare(vma
))) {
4049 goto out_release_all
;
4052 copy_user_huge_page(new_page
, old_page
, address
, vma
,
4053 pages_per_huge_page(h
));
4054 __SetPageUptodate(new_page
);
4056 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
4057 haddr
+ huge_page_size(h
));
4058 mmu_notifier_invalidate_range_start(&range
);
4061 * Retake the page table lock to check for racing updates
4062 * before the page tables are altered
4065 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4066 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
4067 ClearPagePrivate(new_page
);
4070 huge_ptep_clear_flush(vma
, haddr
, ptep
);
4071 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
4072 set_huge_pte_at(mm
, haddr
, ptep
,
4073 make_huge_pte(vma
, new_page
, 1));
4074 page_remove_rmap(old_page
, true);
4075 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
4076 set_page_huge_active(new_page
);
4077 /* Make the old page be freed below */
4078 new_page
= old_page
;
4081 mmu_notifier_invalidate_range_end(&range
);
4083 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
4088 spin_lock(ptl
); /* Caller expects lock to be held */
4092 /* Return the pagecache page at a given address within a VMA */
4093 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
4094 struct vm_area_struct
*vma
, unsigned long address
)
4096 struct address_space
*mapping
;
4099 mapping
= vma
->vm_file
->f_mapping
;
4100 idx
= vma_hugecache_offset(h
, vma
, address
);
4102 return find_lock_page(mapping
, idx
);
4106 * Return whether there is a pagecache page to back given address within VMA.
4107 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4109 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
4110 struct vm_area_struct
*vma
, unsigned long address
)
4112 struct address_space
*mapping
;
4116 mapping
= vma
->vm_file
->f_mapping
;
4117 idx
= vma_hugecache_offset(h
, vma
, address
);
4119 page
= find_get_page(mapping
, idx
);
4122 return page
!= NULL
;
4125 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
4128 struct inode
*inode
= mapping
->host
;
4129 struct hstate
*h
= hstate_inode(inode
);
4130 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
4134 ClearPagePrivate(page
);
4137 * set page dirty so that it will not be removed from cache/file
4138 * by non-hugetlbfs specific code paths.
4140 set_page_dirty(page
);
4142 spin_lock(&inode
->i_lock
);
4143 inode
->i_blocks
+= blocks_per_huge_page(h
);
4144 spin_unlock(&inode
->i_lock
);
4148 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
4149 struct vm_area_struct
*vma
,
4150 struct address_space
*mapping
, pgoff_t idx
,
4151 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
4153 struct hstate
*h
= hstate_vma(vma
);
4154 vm_fault_t ret
= VM_FAULT_SIGBUS
;
4160 unsigned long haddr
= address
& huge_page_mask(h
);
4161 bool new_page
= false;
4164 * Currently, we are forced to kill the process in the event the
4165 * original mapper has unmapped pages from the child due to a failed
4166 * COW. Warn that such a situation has occurred as it may not be obvious
4168 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
4169 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4175 * We can not race with truncation due to holding i_mmap_rwsem.
4176 * i_size is modified when holding i_mmap_rwsem, so check here
4177 * once for faults beyond end of file.
4179 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4184 page
= find_lock_page(mapping
, idx
);
4187 * Check for page in userfault range
4189 if (userfaultfd_missing(vma
)) {
4191 struct vm_fault vmf
= {
4196 * Hard to debug if it ends up being
4197 * used by a callee that assumes
4198 * something about the other
4199 * uninitialized fields... same as in
4205 * hugetlb_fault_mutex and i_mmap_rwsem must be
4206 * dropped before handling userfault. Reacquire
4207 * after handling fault to make calling code simpler.
4209 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4210 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4211 i_mmap_unlock_read(mapping
);
4212 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
4213 i_mmap_lock_read(mapping
);
4214 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4218 page
= alloc_huge_page(vma
, haddr
, 0);
4221 * Returning error will result in faulting task being
4222 * sent SIGBUS. The hugetlb fault mutex prevents two
4223 * tasks from racing to fault in the same page which
4224 * could result in false unable to allocate errors.
4225 * Page migration does not take the fault mutex, but
4226 * does a clear then write of pte's under page table
4227 * lock. Page fault code could race with migration,
4228 * notice the clear pte and try to allocate a page
4229 * here. Before returning error, get ptl and make
4230 * sure there really is no pte entry.
4232 ptl
= huge_pte_lock(h
, mm
, ptep
);
4233 if (!huge_pte_none(huge_ptep_get(ptep
))) {
4239 ret
= vmf_error(PTR_ERR(page
));
4242 clear_huge_page(page
, address
, pages_per_huge_page(h
));
4243 __SetPageUptodate(page
);
4246 if (vma
->vm_flags
& VM_MAYSHARE
) {
4247 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
4256 if (unlikely(anon_vma_prepare(vma
))) {
4258 goto backout_unlocked
;
4264 * If memory error occurs between mmap() and fault, some process
4265 * don't have hwpoisoned swap entry for errored virtual address.
4266 * So we need to block hugepage fault by PG_hwpoison bit check.
4268 if (unlikely(PageHWPoison(page
))) {
4269 ret
= VM_FAULT_HWPOISON
|
4270 VM_FAULT_SET_HINDEX(hstate_index(h
));
4271 goto backout_unlocked
;
4276 * If we are going to COW a private mapping later, we examine the
4277 * pending reservations for this page now. This will ensure that
4278 * any allocations necessary to record that reservation occur outside
4281 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4282 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4284 goto backout_unlocked
;
4286 /* Just decrements count, does not deallocate */
4287 vma_end_reservation(h
, vma
, haddr
);
4290 ptl
= huge_pte_lock(h
, mm
, ptep
);
4292 if (!huge_pte_none(huge_ptep_get(ptep
)))
4296 ClearPagePrivate(page
);
4297 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
4299 page_dup_rmap(page
, true);
4300 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
4301 && (vma
->vm_flags
& VM_SHARED
)));
4302 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
4304 hugetlb_count_add(pages_per_huge_page(h
), mm
);
4305 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4306 /* Optimization, do the COW without a second fault */
4307 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
4313 * Only make newly allocated pages active. Existing pages found
4314 * in the pagecache could be !page_huge_active() if they have been
4315 * isolated for migration.
4318 set_page_huge_active(page
);
4328 restore_reserve_on_error(h
, vma
, haddr
, page
);
4334 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4336 unsigned long key
[2];
4339 key
[0] = (unsigned long) mapping
;
4342 hash
= jhash2((u32
*)&key
, sizeof(key
)/(sizeof(u32
)), 0);
4344 return hash
& (num_fault_mutexes
- 1);
4348 * For uniprocesor systems we always use a single mutex, so just
4349 * return 0 and avoid the hashing overhead.
4351 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4357 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4358 unsigned long address
, unsigned int flags
)
4365 struct page
*page
= NULL
;
4366 struct page
*pagecache_page
= NULL
;
4367 struct hstate
*h
= hstate_vma(vma
);
4368 struct address_space
*mapping
;
4369 int need_wait_lock
= 0;
4370 unsigned long haddr
= address
& huge_page_mask(h
);
4372 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4375 * Since we hold no locks, ptep could be stale. That is
4376 * OK as we are only making decisions based on content and
4377 * not actually modifying content here.
4379 entry
= huge_ptep_get(ptep
);
4380 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4381 migration_entry_wait_huge(vma
, mm
, ptep
);
4383 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4384 return VM_FAULT_HWPOISON_LARGE
|
4385 VM_FAULT_SET_HINDEX(hstate_index(h
));
4387 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4389 return VM_FAULT_OOM
;
4393 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4394 * until finished with ptep. This serves two purposes:
4395 * 1) It prevents huge_pmd_unshare from being called elsewhere
4396 * and making the ptep no longer valid.
4397 * 2) It synchronizes us with i_size modifications during truncation.
4399 * ptep could have already be assigned via huge_pte_offset. That
4400 * is OK, as huge_pte_alloc will return the same value unless
4401 * something has changed.
4403 mapping
= vma
->vm_file
->f_mapping
;
4404 i_mmap_lock_read(mapping
);
4405 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4407 i_mmap_unlock_read(mapping
);
4408 return VM_FAULT_OOM
;
4412 * Serialize hugepage allocation and instantiation, so that we don't
4413 * get spurious allocation failures if two CPUs race to instantiate
4414 * the same page in the page cache.
4416 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4417 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4418 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4420 entry
= huge_ptep_get(ptep
);
4421 if (huge_pte_none(entry
)) {
4422 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4429 * entry could be a migration/hwpoison entry at this point, so this
4430 * check prevents the kernel from going below assuming that we have
4431 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4432 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4435 if (!pte_present(entry
))
4439 * If we are going to COW the mapping later, we examine the pending
4440 * reservations for this page now. This will ensure that any
4441 * allocations necessary to record that reservation occur outside the
4442 * spinlock. For private mappings, we also lookup the pagecache
4443 * page now as it is used to determine if a reservation has been
4446 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4447 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4451 /* Just decrements count, does not deallocate */
4452 vma_end_reservation(h
, vma
, haddr
);
4454 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4455 pagecache_page
= hugetlbfs_pagecache_page(h
,
4459 ptl
= huge_pte_lock(h
, mm
, ptep
);
4461 /* Check for a racing update before calling hugetlb_cow */
4462 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4466 * hugetlb_cow() requires page locks of pte_page(entry) and
4467 * pagecache_page, so here we need take the former one
4468 * when page != pagecache_page or !pagecache_page.
4470 page
= pte_page(entry
);
4471 if (page
!= pagecache_page
)
4472 if (!trylock_page(page
)) {
4479 if (flags
& FAULT_FLAG_WRITE
) {
4480 if (!huge_pte_write(entry
)) {
4481 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4482 pagecache_page
, ptl
);
4485 entry
= huge_pte_mkdirty(entry
);
4487 entry
= pte_mkyoung(entry
);
4488 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4489 flags
& FAULT_FLAG_WRITE
))
4490 update_mmu_cache(vma
, haddr
, ptep
);
4492 if (page
!= pagecache_page
)
4498 if (pagecache_page
) {
4499 unlock_page(pagecache_page
);
4500 put_page(pagecache_page
);
4503 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4504 i_mmap_unlock_read(mapping
);
4506 * Generally it's safe to hold refcount during waiting page lock. But
4507 * here we just wait to defer the next page fault to avoid busy loop and
4508 * the page is not used after unlocked before returning from the current
4509 * page fault. So we are safe from accessing freed page, even if we wait
4510 * here without taking refcount.
4513 wait_on_page_locked(page
);
4518 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4519 * modifications for huge pages.
4521 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4523 struct vm_area_struct
*dst_vma
,
4524 unsigned long dst_addr
,
4525 unsigned long src_addr
,
4526 struct page
**pagep
)
4528 struct address_space
*mapping
;
4531 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4532 struct hstate
*h
= hstate_vma(dst_vma
);
4540 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4544 ret
= copy_huge_page_from_user(page
,
4545 (const void __user
*) src_addr
,
4546 pages_per_huge_page(h
), false);
4548 /* fallback to copy_from_user outside mmap_sem */
4549 if (unlikely(ret
)) {
4552 /* don't free the page */
4561 * The memory barrier inside __SetPageUptodate makes sure that
4562 * preceding stores to the page contents become visible before
4563 * the set_pte_at() write.
4565 __SetPageUptodate(page
);
4567 mapping
= dst_vma
->vm_file
->f_mapping
;
4568 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4571 * If shared, add to page cache
4574 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4577 goto out_release_nounlock
;
4580 * Serialization between remove_inode_hugepages() and
4581 * huge_add_to_page_cache() below happens through the
4582 * hugetlb_fault_mutex_table that here must be hold by
4585 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4587 goto out_release_nounlock
;
4590 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4594 * Recheck the i_size after holding PT lock to make sure not
4595 * to leave any page mapped (as page_mapped()) beyond the end
4596 * of the i_size (remove_inode_hugepages() is strict about
4597 * enforcing that). If we bail out here, we'll also leave a
4598 * page in the radix tree in the vm_shared case beyond the end
4599 * of the i_size, but remove_inode_hugepages() will take care
4600 * of it as soon as we drop the hugetlb_fault_mutex_table.
4602 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4605 goto out_release_unlock
;
4608 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4609 goto out_release_unlock
;
4612 page_dup_rmap(page
, true);
4614 ClearPagePrivate(page
);
4615 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4618 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4619 if (dst_vma
->vm_flags
& VM_WRITE
)
4620 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4621 _dst_pte
= pte_mkyoung(_dst_pte
);
4623 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4625 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4626 dst_vma
->vm_flags
& VM_WRITE
);
4627 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4629 /* No need to invalidate - it was non-present before */
4630 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4633 set_page_huge_active(page
);
4643 out_release_nounlock
:
4648 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4649 struct page
**pages
, struct vm_area_struct
**vmas
,
4650 unsigned long *position
, unsigned long *nr_pages
,
4651 long i
, unsigned int flags
, int *locked
)
4653 unsigned long pfn_offset
;
4654 unsigned long vaddr
= *position
;
4655 unsigned long remainder
= *nr_pages
;
4656 struct hstate
*h
= hstate_vma(vma
);
4659 while (vaddr
< vma
->vm_end
&& remainder
) {
4661 spinlock_t
*ptl
= NULL
;
4666 * If we have a pending SIGKILL, don't keep faulting pages and
4667 * potentially allocating memory.
4669 if (fatal_signal_pending(current
)) {
4675 * Some archs (sparc64, sh*) have multiple pte_ts to
4676 * each hugepage. We have to make sure we get the
4677 * first, for the page indexing below to work.
4679 * Note that page table lock is not held when pte is null.
4681 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4684 ptl
= huge_pte_lock(h
, mm
, pte
);
4685 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4688 * When coredumping, it suits get_dump_page if we just return
4689 * an error where there's an empty slot with no huge pagecache
4690 * to back it. This way, we avoid allocating a hugepage, and
4691 * the sparse dumpfile avoids allocating disk blocks, but its
4692 * huge holes still show up with zeroes where they need to be.
4694 if (absent
&& (flags
& FOLL_DUMP
) &&
4695 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4703 * We need call hugetlb_fault for both hugepages under migration
4704 * (in which case hugetlb_fault waits for the migration,) and
4705 * hwpoisoned hugepages (in which case we need to prevent the
4706 * caller from accessing to them.) In order to do this, we use
4707 * here is_swap_pte instead of is_hugetlb_entry_migration and
4708 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4709 * both cases, and because we can't follow correct pages
4710 * directly from any kind of swap entries.
4712 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4713 ((flags
& FOLL_WRITE
) &&
4714 !huge_pte_write(huge_ptep_get(pte
)))) {
4716 unsigned int fault_flags
= 0;
4720 if (flags
& FOLL_WRITE
)
4721 fault_flags
|= FAULT_FLAG_WRITE
;
4723 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4724 FAULT_FLAG_KILLABLE
;
4725 if (flags
& FOLL_NOWAIT
)
4726 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4727 FAULT_FLAG_RETRY_NOWAIT
;
4728 if (flags
& FOLL_TRIED
) {
4730 * Note: FAULT_FLAG_ALLOW_RETRY and
4731 * FAULT_FLAG_TRIED can co-exist
4733 fault_flags
|= FAULT_FLAG_TRIED
;
4735 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4736 if (ret
& VM_FAULT_ERROR
) {
4737 err
= vm_fault_to_errno(ret
, flags
);
4741 if (ret
& VM_FAULT_RETRY
) {
4743 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4747 * VM_FAULT_RETRY must not return an
4748 * error, it will return zero
4751 * No need to update "position" as the
4752 * caller will not check it after
4753 * *nr_pages is set to 0.
4760 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4761 page
= pte_page(huge_ptep_get(pte
));
4764 * If subpage information not requested, update counters
4765 * and skip the same_page loop below.
4767 if (!pages
&& !vmas
&& !pfn_offset
&&
4768 (vaddr
+ huge_page_size(h
) < vma
->vm_end
) &&
4769 (remainder
>= pages_per_huge_page(h
))) {
4770 vaddr
+= huge_page_size(h
);
4771 remainder
-= pages_per_huge_page(h
);
4772 i
+= pages_per_huge_page(h
);
4779 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4781 * try_grab_page() should always succeed here, because:
4782 * a) we hold the ptl lock, and b) we've just checked
4783 * that the huge page is present in the page tables. If
4784 * the huge page is present, then the tail pages must
4785 * also be present. The ptl prevents the head page and
4786 * tail pages from being rearranged in any way. So this
4787 * page must be available at this point, unless the page
4788 * refcount overflowed:
4790 if (WARN_ON_ONCE(!try_grab_page(pages
[i
], flags
))) {
4805 if (vaddr
< vma
->vm_end
&& remainder
&&
4806 pfn_offset
< pages_per_huge_page(h
)) {
4808 * We use pfn_offset to avoid touching the pageframes
4809 * of this compound page.
4815 *nr_pages
= remainder
;
4817 * setting position is actually required only if remainder is
4818 * not zero but it's faster not to add a "if (remainder)"
4826 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4828 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4831 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4834 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4835 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4837 struct mm_struct
*mm
= vma
->vm_mm
;
4838 unsigned long start
= address
;
4841 struct hstate
*h
= hstate_vma(vma
);
4842 unsigned long pages
= 0;
4843 bool shared_pmd
= false;
4844 struct mmu_notifier_range range
;
4847 * In the case of shared PMDs, the area to flush could be beyond
4848 * start/end. Set range.start/range.end to cover the maximum possible
4849 * range if PMD sharing is possible.
4851 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
4852 0, vma
, mm
, start
, end
);
4853 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
4855 BUG_ON(address
>= end
);
4856 flush_cache_range(vma
, range
.start
, range
.end
);
4858 mmu_notifier_invalidate_range_start(&range
);
4859 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4860 for (; address
< end
; address
+= huge_page_size(h
)) {
4862 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4865 ptl
= huge_pte_lock(h
, mm
, ptep
);
4866 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4872 pte
= huge_ptep_get(ptep
);
4873 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4877 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4878 swp_entry_t entry
= pte_to_swp_entry(pte
);
4880 if (is_write_migration_entry(entry
)) {
4883 make_migration_entry_read(&entry
);
4884 newpte
= swp_entry_to_pte(entry
);
4885 set_huge_swap_pte_at(mm
, address
, ptep
,
4886 newpte
, huge_page_size(h
));
4892 if (!huge_pte_none(pte
)) {
4895 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
4896 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
4897 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4898 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
4904 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4905 * may have cleared our pud entry and done put_page on the page table:
4906 * once we release i_mmap_rwsem, another task can do the final put_page
4907 * and that page table be reused and filled with junk. If we actually
4908 * did unshare a page of pmds, flush the range corresponding to the pud.
4911 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
4913 flush_hugetlb_tlb_range(vma
, start
, end
);
4915 * No need to call mmu_notifier_invalidate_range() we are downgrading
4916 * page table protection not changing it to point to a new page.
4918 * See Documentation/vm/mmu_notifier.rst
4920 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4921 mmu_notifier_invalidate_range_end(&range
);
4923 return pages
<< h
->order
;
4926 int hugetlb_reserve_pages(struct inode
*inode
,
4928 struct vm_area_struct
*vma
,
4929 vm_flags_t vm_flags
)
4931 long ret
, chg
, add
= -1;
4932 struct hstate
*h
= hstate_inode(inode
);
4933 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4934 struct resv_map
*resv_map
;
4935 struct hugetlb_cgroup
*h_cg
= NULL
;
4936 long gbl_reserve
, regions_needed
= 0;
4938 /* This should never happen */
4940 VM_WARN(1, "%s called with a negative range\n", __func__
);
4945 * Only apply hugepage reservation if asked. At fault time, an
4946 * attempt will be made for VM_NORESERVE to allocate a page
4947 * without using reserves
4949 if (vm_flags
& VM_NORESERVE
)
4953 * Shared mappings base their reservation on the number of pages that
4954 * are already allocated on behalf of the file. Private mappings need
4955 * to reserve the full area even if read-only as mprotect() may be
4956 * called to make the mapping read-write. Assume !vma is a shm mapping
4958 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4960 * resv_map can not be NULL as hugetlb_reserve_pages is only
4961 * called for inodes for which resv_maps were created (see
4962 * hugetlbfs_get_inode).
4964 resv_map
= inode_resv_map(inode
);
4966 chg
= region_chg(resv_map
, from
, to
, ®ions_needed
);
4969 /* Private mapping. */
4970 resv_map
= resv_map_alloc();
4976 set_vma_resv_map(vma
, resv_map
);
4977 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4985 ret
= hugetlb_cgroup_charge_cgroup_rsvd(
4986 hstate_index(h
), chg
* pages_per_huge_page(h
), &h_cg
);
4993 if (vma
&& !(vma
->vm_flags
& VM_MAYSHARE
) && h_cg
) {
4994 /* For private mappings, the hugetlb_cgroup uncharge info hangs
4997 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, h_cg
, h
);
5001 * There must be enough pages in the subpool for the mapping. If
5002 * the subpool has a minimum size, there may be some global
5003 * reservations already in place (gbl_reserve).
5005 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
5006 if (gbl_reserve
< 0) {
5008 goto out_uncharge_cgroup
;
5012 * Check enough hugepages are available for the reservation.
5013 * Hand the pages back to the subpool if there are not
5015 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
5021 * Account for the reservations made. Shared mappings record regions
5022 * that have reservations as they are shared by multiple VMAs.
5023 * When the last VMA disappears, the region map says how much
5024 * the reservation was and the page cache tells how much of
5025 * the reservation was consumed. Private mappings are per-VMA and
5026 * only the consumed reservations are tracked. When the VMA
5027 * disappears, the original reservation is the VMA size and the
5028 * consumed reservations are stored in the map. Hence, nothing
5029 * else has to be done for private mappings here
5031 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
5032 add
= region_add(resv_map
, from
, to
, regions_needed
, h
, h_cg
);
5034 if (unlikely(add
< 0)) {
5035 hugetlb_acct_memory(h
, -gbl_reserve
);
5037 } else if (unlikely(chg
> add
)) {
5039 * pages in this range were added to the reserve
5040 * map between region_chg and region_add. This
5041 * indicates a race with alloc_huge_page. Adjust
5042 * the subpool and reserve counts modified above
5043 * based on the difference.
5047 hugetlb_cgroup_uncharge_cgroup_rsvd(
5049 (chg
- add
) * pages_per_huge_page(h
), h_cg
);
5051 rsv_adjust
= hugepage_subpool_put_pages(spool
,
5053 hugetlb_acct_memory(h
, -rsv_adjust
);
5058 /* put back original number of pages, chg */
5059 (void)hugepage_subpool_put_pages(spool
, chg
);
5060 out_uncharge_cgroup
:
5061 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h
),
5062 chg
* pages_per_huge_page(h
), h_cg
);
5064 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
5065 /* Only call region_abort if the region_chg succeeded but the
5066 * region_add failed or didn't run.
5068 if (chg
>= 0 && add
< 0)
5069 region_abort(resv_map
, from
, to
, regions_needed
);
5070 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
5071 kref_put(&resv_map
->refs
, resv_map_release
);
5075 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
5078 struct hstate
*h
= hstate_inode(inode
);
5079 struct resv_map
*resv_map
= inode_resv_map(inode
);
5081 struct hugepage_subpool
*spool
= subpool_inode(inode
);
5085 * Since this routine can be called in the evict inode path for all
5086 * hugetlbfs inodes, resv_map could be NULL.
5089 chg
= region_del(resv_map
, start
, end
);
5091 * region_del() can fail in the rare case where a region
5092 * must be split and another region descriptor can not be
5093 * allocated. If end == LONG_MAX, it will not fail.
5099 spin_lock(&inode
->i_lock
);
5100 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
5101 spin_unlock(&inode
->i_lock
);
5104 * If the subpool has a minimum size, the number of global
5105 * reservations to be released may be adjusted.
5107 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
5108 hugetlb_acct_memory(h
, -gbl_reserve
);
5113 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5114 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
5115 struct vm_area_struct
*vma
,
5116 unsigned long addr
, pgoff_t idx
)
5118 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
5120 unsigned long sbase
= saddr
& PUD_MASK
;
5121 unsigned long s_end
= sbase
+ PUD_SIZE
;
5123 /* Allow segments to share if only one is marked locked */
5124 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5125 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5128 * match the virtual addresses, permission and the alignment of the
5131 if (pmd_index(addr
) != pmd_index(saddr
) ||
5132 vm_flags
!= svm_flags
||
5133 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
5139 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
5141 unsigned long base
= addr
& PUD_MASK
;
5142 unsigned long end
= base
+ PUD_SIZE
;
5145 * check on proper vm_flags and page table alignment
5147 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
5153 * Determine if start,end range within vma could be mapped by shared pmd.
5154 * If yes, adjust start and end to cover range associated with possible
5155 * shared pmd mappings.
5157 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5158 unsigned long *start
, unsigned long *end
)
5160 unsigned long check_addr
;
5162 if (!(vma
->vm_flags
& VM_MAYSHARE
))
5165 for (check_addr
= *start
; check_addr
< *end
; check_addr
+= PUD_SIZE
) {
5166 unsigned long a_start
= check_addr
& PUD_MASK
;
5167 unsigned long a_end
= a_start
+ PUD_SIZE
;
5170 * If sharing is possible, adjust start/end if necessary.
5172 if (range_in_vma(vma
, a_start
, a_end
)) {
5173 if (a_start
< *start
)
5182 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5183 * and returns the corresponding pte. While this is not necessary for the
5184 * !shared pmd case because we can allocate the pmd later as well, it makes the
5185 * code much cleaner.
5187 * This routine must be called with i_mmap_rwsem held in at least read mode.
5188 * For hugetlbfs, this prevents removal of any page table entries associated
5189 * with the address space. This is important as we are setting up sharing
5190 * based on existing page table entries (mappings).
5192 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5194 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
5195 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
5196 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
5198 struct vm_area_struct
*svma
;
5199 unsigned long saddr
;
5204 if (!vma_shareable(vma
, addr
))
5205 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5207 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
5211 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
5213 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
5214 vma_mmu_pagesize(svma
));
5216 get_page(virt_to_page(spte
));
5225 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
5226 if (pud_none(*pud
)) {
5227 pud_populate(mm
, pud
,
5228 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
5231 put_page(virt_to_page(spte
));
5235 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5240 * unmap huge page backed by shared pte.
5242 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5243 * indicated by page_count > 1, unmap is achieved by clearing pud and
5244 * decrementing the ref count. If count == 1, the pte page is not shared.
5246 * Called with page table lock held and i_mmap_rwsem held in write mode.
5248 * returns: 1 successfully unmapped a shared pte page
5249 * 0 the underlying pte page is not shared, or it is the last user
5251 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5253 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
5254 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
5255 pud_t
*pud
= pud_offset(p4d
, *addr
);
5257 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
5258 if (page_count(virt_to_page(ptep
)) == 1)
5262 put_page(virt_to_page(ptep
));
5264 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
5267 #define want_pmd_share() (1)
5268 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5269 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5274 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5279 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5280 unsigned long *start
, unsigned long *end
)
5283 #define want_pmd_share() (0)
5284 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5286 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5287 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
5288 unsigned long addr
, unsigned long sz
)
5295 pgd
= pgd_offset(mm
, addr
);
5296 p4d
= p4d_alloc(mm
, pgd
, addr
);
5299 pud
= pud_alloc(mm
, p4d
, addr
);
5301 if (sz
== PUD_SIZE
) {
5304 BUG_ON(sz
!= PMD_SIZE
);
5305 if (want_pmd_share() && pud_none(*pud
))
5306 pte
= huge_pmd_share(mm
, addr
, pud
);
5308 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5311 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
5317 * huge_pte_offset() - Walk the page table to resolve the hugepage
5318 * entry at address @addr
5320 * Return: Pointer to page table or swap entry (PUD or PMD) for
5321 * address @addr, or NULL if a p*d_none() entry is encountered and the
5322 * size @sz doesn't match the hugepage size at this level of the page
5325 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
5326 unsigned long addr
, unsigned long sz
)
5333 pgd
= pgd_offset(mm
, addr
);
5334 if (!pgd_present(*pgd
))
5336 p4d
= p4d_offset(pgd
, addr
);
5337 if (!p4d_present(*p4d
))
5340 pud
= pud_offset(p4d
, addr
);
5341 if (sz
!= PUD_SIZE
&& pud_none(*pud
))
5343 /* hugepage or swap? */
5344 if (pud_huge(*pud
) || !pud_present(*pud
))
5345 return (pte_t
*)pud
;
5347 pmd
= pmd_offset(pud
, addr
);
5348 if (sz
!= PMD_SIZE
&& pmd_none(*pmd
))
5350 /* hugepage or swap? */
5351 if (pmd_huge(*pmd
) || !pmd_present(*pmd
))
5352 return (pte_t
*)pmd
;
5357 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5360 * These functions are overwritable if your architecture needs its own
5363 struct page
* __weak
5364 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
5367 return ERR_PTR(-EINVAL
);
5370 struct page
* __weak
5371 follow_huge_pd(struct vm_area_struct
*vma
,
5372 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
5374 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5378 struct page
* __weak
5379 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
5380 pmd_t
*pmd
, int flags
)
5382 struct page
*page
= NULL
;
5386 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5387 if (WARN_ON_ONCE((flags
& (FOLL_PIN
| FOLL_GET
)) ==
5388 (FOLL_PIN
| FOLL_GET
)))
5392 ptl
= pmd_lockptr(mm
, pmd
);
5395 * make sure that the address range covered by this pmd is not
5396 * unmapped from other threads.
5398 if (!pmd_huge(*pmd
))
5400 pte
= huge_ptep_get((pte_t
*)pmd
);
5401 if (pte_present(pte
)) {
5402 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
5404 * try_grab_page() should always succeed here, because: a) we
5405 * hold the pmd (ptl) lock, and b) we've just checked that the
5406 * huge pmd (head) page is present in the page tables. The ptl
5407 * prevents the head page and tail pages from being rearranged
5408 * in any way. So this page must be available at this point,
5409 * unless the page refcount overflowed:
5411 if (WARN_ON_ONCE(!try_grab_page(page
, flags
))) {
5416 if (is_hugetlb_entry_migration(pte
)) {
5418 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5422 * hwpoisoned entry is treated as no_page_table in
5423 * follow_page_mask().
5431 struct page
* __weak
5432 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5433 pud_t
*pud
, int flags
)
5435 if (flags
& (FOLL_GET
| FOLL_PIN
))
5438 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5441 struct page
* __weak
5442 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5444 if (flags
& (FOLL_GET
| FOLL_PIN
))
5447 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5450 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5454 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5455 spin_lock(&hugetlb_lock
);
5456 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
5460 clear_page_huge_active(page
);
5461 list_move_tail(&page
->lru
, list
);
5463 spin_unlock(&hugetlb_lock
);
5467 void putback_active_hugepage(struct page
*page
)
5469 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5470 spin_lock(&hugetlb_lock
);
5471 set_page_huge_active(page
);
5472 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5473 spin_unlock(&hugetlb_lock
);
5477 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5479 struct hstate
*h
= page_hstate(oldpage
);
5481 hugetlb_cgroup_migrate(oldpage
, newpage
);
5482 set_page_owner_migrate_reason(newpage
, reason
);
5485 * transfer temporary state of the new huge page. This is
5486 * reverse to other transitions because the newpage is going to
5487 * be final while the old one will be freed so it takes over
5488 * the temporary status.
5490 * Also note that we have to transfer the per-node surplus state
5491 * here as well otherwise the global surplus count will not match
5494 if (PageHugeTemporary(newpage
)) {
5495 int old_nid
= page_to_nid(oldpage
);
5496 int new_nid
= page_to_nid(newpage
);
5498 SetPageHugeTemporary(oldpage
);
5499 ClearPageHugeTemporary(newpage
);
5501 spin_lock(&hugetlb_lock
);
5502 if (h
->surplus_huge_pages_node
[old_nid
]) {
5503 h
->surplus_huge_pages_node
[old_nid
]--;
5504 h
->surplus_huge_pages_node
[new_nid
]++;
5506 spin_unlock(&hugetlb_lock
);