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>
31 #include <linux/cma.h>
34 #include <asm/pgtable.h>
38 #include <linux/hugetlb.h>
39 #include <linux/hugetlb_cgroup.h>
40 #include <linux/node.h>
41 #include <linux/userfaultfd_k.h>
42 #include <linux/page_owner.h>
45 int hugetlb_max_hstate __read_mostly
;
46 unsigned int default_hstate_idx
;
47 struct hstate hstates
[HUGE_MAX_HSTATE
];
49 static struct cma
*hugetlb_cma
[MAX_NUMNODES
];
52 * Minimum page order among possible hugepage sizes, set to a proper value
55 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
57 __initdata
LIST_HEAD(huge_boot_pages
);
59 /* for command line parsing */
60 static struct hstate
* __initdata parsed_hstate
;
61 static unsigned long __initdata default_hstate_max_huge_pages
;
62 static bool __initdata parsed_valid_hugepagesz
= true;
63 static bool __initdata parsed_default_hugepagesz
;
66 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
67 * free_huge_pages, and surplus_huge_pages.
69 DEFINE_SPINLOCK(hugetlb_lock
);
72 * Serializes faults on the same logical page. This is used to
73 * prevent spurious OOMs when the hugepage pool is fully utilized.
75 static int num_fault_mutexes
;
76 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
78 /* Forward declaration */
79 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
81 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
83 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
85 spin_unlock(&spool
->lock
);
87 /* If no pages are used, and no other handles to the subpool
88 * remain, give up any reservations mased on minimum size and
91 if (spool
->min_hpages
!= -1)
92 hugetlb_acct_memory(spool
->hstate
,
98 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
101 struct hugepage_subpool
*spool
;
103 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
107 spin_lock_init(&spool
->lock
);
109 spool
->max_hpages
= max_hpages
;
111 spool
->min_hpages
= min_hpages
;
113 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
117 spool
->rsv_hpages
= min_hpages
;
122 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
124 spin_lock(&spool
->lock
);
125 BUG_ON(!spool
->count
);
127 unlock_or_release_subpool(spool
);
131 * Subpool accounting for allocating and reserving pages.
132 * Return -ENOMEM if there are not enough resources to satisfy the
133 * the request. Otherwise, return the number of pages by which the
134 * global pools must be adjusted (upward). The returned value may
135 * only be different than the passed value (delta) in the case where
136 * a subpool minimum size must be manitained.
138 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
146 spin_lock(&spool
->lock
);
148 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
149 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
150 spool
->used_hpages
+= delta
;
157 /* minimum size accounting */
158 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
159 if (delta
> spool
->rsv_hpages
) {
161 * Asking for more reserves than those already taken on
162 * behalf of subpool. Return difference.
164 ret
= delta
- spool
->rsv_hpages
;
165 spool
->rsv_hpages
= 0;
167 ret
= 0; /* reserves already accounted for */
168 spool
->rsv_hpages
-= delta
;
173 spin_unlock(&spool
->lock
);
178 * Subpool accounting for freeing and unreserving pages.
179 * Return the number of global page reservations that must be dropped.
180 * The return value may only be different than the passed value (delta)
181 * in the case where a subpool minimum size must be maintained.
183 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
191 spin_lock(&spool
->lock
);
193 if (spool
->max_hpages
!= -1) /* maximum size accounting */
194 spool
->used_hpages
-= delta
;
196 /* minimum size accounting */
197 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
198 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
201 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
203 spool
->rsv_hpages
+= delta
;
204 if (spool
->rsv_hpages
> spool
->min_hpages
)
205 spool
->rsv_hpages
= spool
->min_hpages
;
209 * If hugetlbfs_put_super couldn't free spool due to an outstanding
210 * quota reference, free it now.
212 unlock_or_release_subpool(spool
);
217 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
219 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
222 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
224 return subpool_inode(file_inode(vma
->vm_file
));
227 /* Helper that removes a struct file_region from the resv_map cache and returns
230 static struct file_region
*
231 get_file_region_entry_from_cache(struct resv_map
*resv
, long from
, long to
)
233 struct file_region
*nrg
= NULL
;
235 VM_BUG_ON(resv
->region_cache_count
<= 0);
237 resv
->region_cache_count
--;
238 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
, link
);
240 list_del(&nrg
->link
);
248 static void copy_hugetlb_cgroup_uncharge_info(struct file_region
*nrg
,
249 struct file_region
*rg
)
251 #ifdef CONFIG_CGROUP_HUGETLB
252 nrg
->reservation_counter
= rg
->reservation_counter
;
259 /* Helper that records hugetlb_cgroup uncharge info. */
260 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup
*h_cg
,
262 struct resv_map
*resv
,
263 struct file_region
*nrg
)
265 #ifdef CONFIG_CGROUP_HUGETLB
267 nrg
->reservation_counter
=
268 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
269 nrg
->css
= &h_cg
->css
;
270 if (!resv
->pages_per_hpage
)
271 resv
->pages_per_hpage
= pages_per_huge_page(h
);
272 /* pages_per_hpage should be the same for all entries in
275 VM_BUG_ON(resv
->pages_per_hpage
!= pages_per_huge_page(h
));
277 nrg
->reservation_counter
= NULL
;
283 static bool has_same_uncharge_info(struct file_region
*rg
,
284 struct file_region
*org
)
286 #ifdef CONFIG_CGROUP_HUGETLB
288 rg
->reservation_counter
== org
->reservation_counter
&&
296 static void coalesce_file_region(struct resv_map
*resv
, struct file_region
*rg
)
298 struct file_region
*nrg
= NULL
, *prg
= NULL
;
300 prg
= list_prev_entry(rg
, link
);
301 if (&prg
->link
!= &resv
->regions
&& prg
->to
== rg
->from
&&
302 has_same_uncharge_info(prg
, rg
)) {
308 coalesce_file_region(resv
, prg
);
312 nrg
= list_next_entry(rg
, link
);
313 if (&nrg
->link
!= &resv
->regions
&& nrg
->from
== rg
->to
&&
314 has_same_uncharge_info(nrg
, rg
)) {
315 nrg
->from
= rg
->from
;
320 coalesce_file_region(resv
, nrg
);
325 /* Must be called with resv->lock held. Calling this with count_only == true
326 * will count the number of pages to be added but will not modify the linked
327 * list. If regions_needed != NULL and count_only == true, then regions_needed
328 * will indicate the number of file_regions needed in the cache to carry out to
329 * add the regions for this range.
331 static long add_reservation_in_range(struct resv_map
*resv
, long f
, long t
,
332 struct hugetlb_cgroup
*h_cg
,
333 struct hstate
*h
, long *regions_needed
,
337 struct list_head
*head
= &resv
->regions
;
338 long last_accounted_offset
= f
;
339 struct file_region
*rg
= NULL
, *trg
= NULL
, *nrg
= NULL
;
344 /* In this loop, we essentially handle an entry for the range
345 * [last_accounted_offset, rg->from), at every iteration, with some
348 list_for_each_entry_safe(rg
, trg
, head
, link
) {
349 /* Skip irrelevant regions that start before our range. */
351 /* If this region ends after the last accounted offset,
352 * then we need to update last_accounted_offset.
354 if (rg
->to
> last_accounted_offset
)
355 last_accounted_offset
= rg
->to
;
359 /* When we find a region that starts beyond our range, we've
365 /* Add an entry for last_accounted_offset -> rg->from, and
366 * update last_accounted_offset.
368 if (rg
->from
> last_accounted_offset
) {
369 add
+= rg
->from
- last_accounted_offset
;
371 nrg
= get_file_region_entry_from_cache(
372 resv
, last_accounted_offset
, rg
->from
);
373 record_hugetlb_cgroup_uncharge_info(h_cg
, h
,
375 list_add(&nrg
->link
, rg
->link
.prev
);
376 coalesce_file_region(resv
, nrg
);
377 } else if (regions_needed
)
378 *regions_needed
+= 1;
381 last_accounted_offset
= rg
->to
;
384 /* Handle the case where our range extends beyond
385 * last_accounted_offset.
387 if (last_accounted_offset
< t
) {
388 add
+= t
- last_accounted_offset
;
390 nrg
= get_file_region_entry_from_cache(
391 resv
, last_accounted_offset
, t
);
392 record_hugetlb_cgroup_uncharge_info(h_cg
, h
, resv
, nrg
);
393 list_add(&nrg
->link
, rg
->link
.prev
);
394 coalesce_file_region(resv
, nrg
);
395 } else if (regions_needed
)
396 *regions_needed
+= 1;
403 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
405 static int allocate_file_region_entries(struct resv_map
*resv
,
407 __must_hold(&resv
->lock
)
409 struct list_head allocated_regions
;
410 int to_allocate
= 0, i
= 0;
411 struct file_region
*trg
= NULL
, *rg
= NULL
;
413 VM_BUG_ON(regions_needed
< 0);
415 INIT_LIST_HEAD(&allocated_regions
);
418 * Check for sufficient descriptors in the cache to accommodate
419 * the number of in progress add operations plus regions_needed.
421 * This is a while loop because when we drop the lock, some other call
422 * to region_add or region_del may have consumed some region_entries,
423 * so we keep looping here until we finally have enough entries for
424 * (adds_in_progress + regions_needed).
426 while (resv
->region_cache_count
<
427 (resv
->adds_in_progress
+ regions_needed
)) {
428 to_allocate
= resv
->adds_in_progress
+ regions_needed
-
429 resv
->region_cache_count
;
431 /* At this point, we should have enough entries in the cache
432 * for all the existings adds_in_progress. We should only be
433 * needing to allocate for regions_needed.
435 VM_BUG_ON(resv
->region_cache_count
< resv
->adds_in_progress
);
437 spin_unlock(&resv
->lock
);
438 for (i
= 0; i
< to_allocate
; i
++) {
439 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
442 list_add(&trg
->link
, &allocated_regions
);
445 spin_lock(&resv
->lock
);
447 list_for_each_entry_safe(rg
, trg
, &allocated_regions
, link
) {
449 list_add(&rg
->link
, &resv
->region_cache
);
450 resv
->region_cache_count
++;
457 list_for_each_entry_safe(rg
, trg
, &allocated_regions
, link
) {
465 * Add the huge page range represented by [f, t) to the reserve
466 * map. Regions will be taken from the cache to fill in this range.
467 * Sufficient regions should exist in the cache due to the previous
468 * call to region_chg with the same range, but in some cases the cache will not
469 * have sufficient entries due to races with other code doing region_add or
470 * region_del. The extra needed entries will be allocated.
472 * regions_needed is the out value provided by a previous call to region_chg.
474 * Return the number of new huge pages added to the map. This number is greater
475 * than or equal to zero. If file_region entries needed to be allocated for
476 * this operation and we were not able to allocate, it ruturns -ENOMEM.
477 * region_add of regions of length 1 never allocate file_regions and cannot
478 * fail; region_chg will always allocate at least 1 entry and a region_add for
479 * 1 page will only require at most 1 entry.
481 static long region_add(struct resv_map
*resv
, long f
, long t
,
482 long in_regions_needed
, struct hstate
*h
,
483 struct hugetlb_cgroup
*h_cg
)
485 long add
= 0, actual_regions_needed
= 0;
487 spin_lock(&resv
->lock
);
490 /* Count how many regions are actually needed to execute this add. */
491 add_reservation_in_range(resv
, f
, t
, NULL
, NULL
, &actual_regions_needed
,
495 * Check for sufficient descriptors in the cache to accommodate
496 * this add operation. Note that actual_regions_needed may be greater
497 * than in_regions_needed, as the resv_map may have been modified since
498 * the region_chg call. In this case, we need to make sure that we
499 * allocate extra entries, such that we have enough for all the
500 * existing adds_in_progress, plus the excess needed for this
503 if (actual_regions_needed
> in_regions_needed
&&
504 resv
->region_cache_count
<
505 resv
->adds_in_progress
+
506 (actual_regions_needed
- in_regions_needed
)) {
507 /* region_add operation of range 1 should never need to
508 * allocate file_region entries.
510 VM_BUG_ON(t
- f
<= 1);
512 if (allocate_file_region_entries(
513 resv
, actual_regions_needed
- in_regions_needed
)) {
520 add
= add_reservation_in_range(resv
, f
, t
, h_cg
, h
, NULL
, false);
522 resv
->adds_in_progress
-= in_regions_needed
;
524 spin_unlock(&resv
->lock
);
530 * Examine the existing reserve map and determine how many
531 * huge pages in the specified range [f, t) are NOT currently
532 * represented. This routine is called before a subsequent
533 * call to region_add that will actually modify the reserve
534 * map to add the specified range [f, t). region_chg does
535 * not change the number of huge pages represented by the
536 * map. A number of new file_region structures is added to the cache as a
537 * placeholder, for the subsequent region_add call to use. At least 1
538 * file_region structure is added.
540 * out_regions_needed is the number of regions added to the
541 * resv->adds_in_progress. This value needs to be provided to a follow up call
542 * to region_add or region_abort for proper accounting.
544 * Returns the number of huge pages that need to be added to the existing
545 * reservation map for the range [f, t). This number is greater or equal to
546 * zero. -ENOMEM is returned if a new file_region structure or cache entry
547 * is needed and can not be allocated.
549 static long region_chg(struct resv_map
*resv
, long f
, long t
,
550 long *out_regions_needed
)
554 spin_lock(&resv
->lock
);
556 /* Count how many hugepages in this range are NOT respresented. */
557 chg
= add_reservation_in_range(resv
, f
, t
, NULL
, NULL
,
558 out_regions_needed
, true);
560 if (*out_regions_needed
== 0)
561 *out_regions_needed
= 1;
563 if (allocate_file_region_entries(resv
, *out_regions_needed
))
566 resv
->adds_in_progress
+= *out_regions_needed
;
568 spin_unlock(&resv
->lock
);
573 * Abort the in progress add operation. The adds_in_progress field
574 * of the resv_map keeps track of the operations in progress between
575 * calls to region_chg and region_add. Operations are sometimes
576 * aborted after the call to region_chg. In such cases, region_abort
577 * is called to decrement the adds_in_progress counter. regions_needed
578 * is the value returned by the region_chg call, it is used to decrement
579 * the adds_in_progress counter.
581 * NOTE: The range arguments [f, t) are not needed or used in this
582 * routine. They are kept to make reading the calling code easier as
583 * arguments will match the associated region_chg call.
585 static void region_abort(struct resv_map
*resv
, long f
, long t
,
588 spin_lock(&resv
->lock
);
589 VM_BUG_ON(!resv
->region_cache_count
);
590 resv
->adds_in_progress
-= regions_needed
;
591 spin_unlock(&resv
->lock
);
595 * Delete the specified range [f, t) from the reserve map. If the
596 * t parameter is LONG_MAX, this indicates that ALL regions after f
597 * should be deleted. Locate the regions which intersect [f, t)
598 * and either trim, delete or split the existing regions.
600 * Returns the number of huge pages deleted from the reserve map.
601 * In the normal case, the return value is zero or more. In the
602 * case where a region must be split, a new region descriptor must
603 * be allocated. If the allocation fails, -ENOMEM will be returned.
604 * NOTE: If the parameter t == LONG_MAX, then we will never split
605 * a region and possibly return -ENOMEM. Callers specifying
606 * t == LONG_MAX do not need to check for -ENOMEM error.
608 static long region_del(struct resv_map
*resv
, long f
, long t
)
610 struct list_head
*head
= &resv
->regions
;
611 struct file_region
*rg
, *trg
;
612 struct file_region
*nrg
= NULL
;
616 spin_lock(&resv
->lock
);
617 list_for_each_entry_safe(rg
, trg
, head
, link
) {
619 * Skip regions before the range to be deleted. file_region
620 * ranges are normally of the form [from, to). However, there
621 * may be a "placeholder" entry in the map which is of the form
622 * (from, to) with from == to. Check for placeholder entries
623 * at the beginning of the range to be deleted.
625 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
631 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
633 * Check for an entry in the cache before dropping
634 * lock and attempting allocation.
637 resv
->region_cache_count
> resv
->adds_in_progress
) {
638 nrg
= list_first_entry(&resv
->region_cache
,
641 list_del(&nrg
->link
);
642 resv
->region_cache_count
--;
646 spin_unlock(&resv
->lock
);
647 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
655 /* New entry for end of split region */
659 copy_hugetlb_cgroup_uncharge_info(nrg
, rg
);
661 INIT_LIST_HEAD(&nrg
->link
);
663 /* Original entry is trimmed */
666 hugetlb_cgroup_uncharge_file_region(
667 resv
, rg
, nrg
->to
- nrg
->from
);
669 list_add(&nrg
->link
, &rg
->link
);
674 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
675 del
+= rg
->to
- rg
->from
;
676 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
683 if (f
<= rg
->from
) { /* Trim beginning of region */
687 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
689 } else { /* Trim end of region */
693 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
698 spin_unlock(&resv
->lock
);
704 * A rare out of memory error was encountered which prevented removal of
705 * the reserve map region for a page. The huge page itself was free'ed
706 * and removed from the page cache. This routine will adjust the subpool
707 * usage count, and the global reserve count if needed. By incrementing
708 * these counts, the reserve map entry which could not be deleted will
709 * appear as a "reserved" entry instead of simply dangling with incorrect
712 void hugetlb_fix_reserve_counts(struct inode
*inode
)
714 struct hugepage_subpool
*spool
= subpool_inode(inode
);
717 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
719 struct hstate
*h
= hstate_inode(inode
);
721 hugetlb_acct_memory(h
, 1);
726 * Count and return the number of huge pages in the reserve map
727 * that intersect with the range [f, t).
729 static long region_count(struct resv_map
*resv
, long f
, long t
)
731 struct list_head
*head
= &resv
->regions
;
732 struct file_region
*rg
;
735 spin_lock(&resv
->lock
);
736 /* Locate each segment we overlap with, and count that overlap. */
737 list_for_each_entry(rg
, head
, link
) {
746 seg_from
= max(rg
->from
, f
);
747 seg_to
= min(rg
->to
, t
);
749 chg
+= seg_to
- seg_from
;
751 spin_unlock(&resv
->lock
);
757 * Convert the address within this vma to the page offset within
758 * the mapping, in pagecache page units; huge pages here.
760 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
761 struct vm_area_struct
*vma
, unsigned long address
)
763 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
764 (vma
->vm_pgoff
>> huge_page_order(h
));
767 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
768 unsigned long address
)
770 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
772 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
775 * Return the size of the pages allocated when backing a VMA. In the majority
776 * cases this will be same size as used by the page table entries.
778 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
780 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
781 return vma
->vm_ops
->pagesize(vma
);
784 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
787 * Return the page size being used by the MMU to back a VMA. In the majority
788 * of cases, the page size used by the kernel matches the MMU size. On
789 * architectures where it differs, an architecture-specific 'strong'
790 * version of this symbol is required.
792 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
794 return vma_kernel_pagesize(vma
);
798 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
799 * bits of the reservation map pointer, which are always clear due to
802 #define HPAGE_RESV_OWNER (1UL << 0)
803 #define HPAGE_RESV_UNMAPPED (1UL << 1)
804 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
807 * These helpers are used to track how many pages are reserved for
808 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
809 * is guaranteed to have their future faults succeed.
811 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
812 * the reserve counters are updated with the hugetlb_lock held. It is safe
813 * to reset the VMA at fork() time as it is not in use yet and there is no
814 * chance of the global counters getting corrupted as a result of the values.
816 * The private mapping reservation is represented in a subtly different
817 * manner to a shared mapping. A shared mapping has a region map associated
818 * with the underlying file, this region map represents the backing file
819 * pages which have ever had a reservation assigned which this persists even
820 * after the page is instantiated. A private mapping has a region map
821 * associated with the original mmap which is attached to all VMAs which
822 * reference it, this region map represents those offsets which have consumed
823 * reservation ie. where pages have been instantiated.
825 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
827 return (unsigned long)vma
->vm_private_data
;
830 static void set_vma_private_data(struct vm_area_struct
*vma
,
833 vma
->vm_private_data
= (void *)value
;
837 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map
*resv_map
,
838 struct hugetlb_cgroup
*h_cg
,
841 #ifdef CONFIG_CGROUP_HUGETLB
843 resv_map
->reservation_counter
= NULL
;
844 resv_map
->pages_per_hpage
= 0;
845 resv_map
->css
= NULL
;
847 resv_map
->reservation_counter
=
848 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
849 resv_map
->pages_per_hpage
= pages_per_huge_page(h
);
850 resv_map
->css
= &h_cg
->css
;
855 struct resv_map
*resv_map_alloc(void)
857 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
858 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
860 if (!resv_map
|| !rg
) {
866 kref_init(&resv_map
->refs
);
867 spin_lock_init(&resv_map
->lock
);
868 INIT_LIST_HEAD(&resv_map
->regions
);
870 resv_map
->adds_in_progress
= 0;
872 * Initialize these to 0. On shared mappings, 0's here indicate these
873 * fields don't do cgroup accounting. On private mappings, these will be
874 * re-initialized to the proper values, to indicate that hugetlb cgroup
875 * reservations are to be un-charged from here.
877 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, NULL
, NULL
);
879 INIT_LIST_HEAD(&resv_map
->region_cache
);
880 list_add(&rg
->link
, &resv_map
->region_cache
);
881 resv_map
->region_cache_count
= 1;
886 void resv_map_release(struct kref
*ref
)
888 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
889 struct list_head
*head
= &resv_map
->region_cache
;
890 struct file_region
*rg
, *trg
;
892 /* Clear out any active regions before we release the map. */
893 region_del(resv_map
, 0, LONG_MAX
);
895 /* ... and any entries left in the cache */
896 list_for_each_entry_safe(rg
, trg
, head
, link
) {
901 VM_BUG_ON(resv_map
->adds_in_progress
);
906 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
909 * At inode evict time, i_mapping may not point to the original
910 * address space within the inode. This original address space
911 * contains the pointer to the resv_map. So, always use the
912 * address space embedded within the inode.
913 * The VERY common case is inode->mapping == &inode->i_data but,
914 * this may not be true for device special inodes.
916 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
919 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
921 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
922 if (vma
->vm_flags
& VM_MAYSHARE
) {
923 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
924 struct inode
*inode
= mapping
->host
;
926 return inode_resv_map(inode
);
929 return (struct resv_map
*)(get_vma_private_data(vma
) &
934 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
936 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
937 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
939 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
940 HPAGE_RESV_MASK
) | (unsigned long)map
);
943 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
945 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
946 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
948 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
951 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
953 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
955 return (get_vma_private_data(vma
) & flag
) != 0;
958 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
959 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
961 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
962 if (!(vma
->vm_flags
& VM_MAYSHARE
))
963 vma
->vm_private_data
= (void *)0;
966 /* Returns true if the VMA has associated reserve pages */
967 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
969 if (vma
->vm_flags
& VM_NORESERVE
) {
971 * This address is already reserved by other process(chg == 0),
972 * so, we should decrement reserved count. Without decrementing,
973 * reserve count remains after releasing inode, because this
974 * allocated page will go into page cache and is regarded as
975 * coming from reserved pool in releasing step. Currently, we
976 * don't have any other solution to deal with this situation
977 * properly, so add work-around here.
979 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
985 /* Shared mappings always use reserves */
986 if (vma
->vm_flags
& VM_MAYSHARE
) {
988 * We know VM_NORESERVE is not set. Therefore, there SHOULD
989 * be a region map for all pages. The only situation where
990 * there is no region map is if a hole was punched via
991 * fallocate. In this case, there really are no reverves to
992 * use. This situation is indicated if chg != 0.
1001 * Only the process that called mmap() has reserves for
1004 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1006 * Like the shared case above, a hole punch or truncate
1007 * could have been performed on the private mapping.
1008 * Examine the value of chg to determine if reserves
1009 * actually exist or were previously consumed.
1010 * Very Subtle - The value of chg comes from a previous
1011 * call to vma_needs_reserves(). The reserve map for
1012 * private mappings has different (opposite) semantics
1013 * than that of shared mappings. vma_needs_reserves()
1014 * has already taken this difference in semantics into
1015 * account. Therefore, the meaning of chg is the same
1016 * as in the shared case above. Code could easily be
1017 * combined, but keeping it separate draws attention to
1018 * subtle differences.
1029 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
1031 int nid
= page_to_nid(page
);
1032 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
1033 h
->free_huge_pages
++;
1034 h
->free_huge_pages_node
[nid
]++;
1037 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
1041 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
1042 if (!PageHWPoison(page
))
1045 * if 'non-isolated free hugepage' not found on the list,
1046 * the allocation fails.
1048 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
1050 list_move(&page
->lru
, &h
->hugepage_activelist
);
1051 set_page_refcounted(page
);
1052 h
->free_huge_pages
--;
1053 h
->free_huge_pages_node
[nid
]--;
1057 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
1060 unsigned int cpuset_mems_cookie
;
1061 struct zonelist
*zonelist
;
1064 int node
= NUMA_NO_NODE
;
1066 zonelist
= node_zonelist(nid
, gfp_mask
);
1069 cpuset_mems_cookie
= read_mems_allowed_begin();
1070 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
1073 if (!cpuset_zone_allowed(zone
, gfp_mask
))
1076 * no need to ask again on the same node. Pool is node rather than
1079 if (zone_to_nid(zone
) == node
)
1081 node
= zone_to_nid(zone
);
1083 page
= dequeue_huge_page_node_exact(h
, node
);
1087 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
1093 /* Movability of hugepages depends on migration support. */
1094 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
1096 if (hugepage_movable_supported(h
))
1097 return GFP_HIGHUSER_MOVABLE
;
1099 return GFP_HIGHUSER
;
1102 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
1103 struct vm_area_struct
*vma
,
1104 unsigned long address
, int avoid_reserve
,
1108 struct mempolicy
*mpol
;
1110 nodemask_t
*nodemask
;
1114 * A child process with MAP_PRIVATE mappings created by their parent
1115 * have no page reserves. This check ensures that reservations are
1116 * not "stolen". The child may still get SIGKILLed
1118 if (!vma_has_reserves(vma
, chg
) &&
1119 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1122 /* If reserves cannot be used, ensure enough pages are in the pool */
1123 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1126 gfp_mask
= htlb_alloc_mask(h
);
1127 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1128 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
1129 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
1130 SetPagePrivate(page
);
1131 h
->resv_huge_pages
--;
1134 mpol_cond_put(mpol
);
1142 * common helper functions for hstate_next_node_to_{alloc|free}.
1143 * We may have allocated or freed a huge page based on a different
1144 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1145 * be outside of *nodes_allowed. Ensure that we use an allowed
1146 * node for alloc or free.
1148 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1150 nid
= next_node_in(nid
, *nodes_allowed
);
1151 VM_BUG_ON(nid
>= MAX_NUMNODES
);
1156 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1158 if (!node_isset(nid
, *nodes_allowed
))
1159 nid
= next_node_allowed(nid
, nodes_allowed
);
1164 * returns the previously saved node ["this node"] from which to
1165 * allocate a persistent huge page for the pool and advance the
1166 * next node from which to allocate, handling wrap at end of node
1169 static int hstate_next_node_to_alloc(struct hstate
*h
,
1170 nodemask_t
*nodes_allowed
)
1174 VM_BUG_ON(!nodes_allowed
);
1176 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1177 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1183 * helper for free_pool_huge_page() - return the previously saved
1184 * node ["this node"] from which to free a huge page. Advance the
1185 * next node id whether or not we find a free huge page to free so
1186 * that the next attempt to free addresses the next node.
1188 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1192 VM_BUG_ON(!nodes_allowed
);
1194 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1195 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1200 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1201 for (nr_nodes = nodes_weight(*mask); \
1203 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1206 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1207 for (nr_nodes = nodes_weight(*mask); \
1209 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1212 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1213 static void destroy_compound_gigantic_page(struct page
*page
,
1217 int nr_pages
= 1 << order
;
1218 struct page
*p
= page
+ 1;
1220 atomic_set(compound_mapcount_ptr(page
), 0);
1221 if (hpage_pincount_available(page
))
1222 atomic_set(compound_pincount_ptr(page
), 0);
1224 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1225 clear_compound_head(p
);
1226 set_page_refcounted(p
);
1229 set_compound_order(page
, 0);
1230 __ClearPageHead(page
);
1233 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1236 * If the page isn't allocated using the cma allocator,
1237 * cma_release() returns false.
1239 if (IS_ENABLED(CONFIG_CMA
) &&
1240 cma_release(hugetlb_cma
[page_to_nid(page
)], page
, 1 << order
))
1243 free_contig_range(page_to_pfn(page
), 1 << order
);
1246 #ifdef CONFIG_CONTIG_ALLOC
1247 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1248 int nid
, nodemask_t
*nodemask
)
1250 unsigned long nr_pages
= 1UL << huge_page_order(h
);
1252 if (IS_ENABLED(CONFIG_CMA
)) {
1256 for_each_node_mask(node
, *nodemask
) {
1257 if (!hugetlb_cma
[node
])
1260 page
= cma_alloc(hugetlb_cma
[node
], nr_pages
,
1261 huge_page_order(h
), true);
1267 return alloc_contig_pages(nr_pages
, gfp_mask
, nid
, nodemask
);
1270 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1271 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1272 #else /* !CONFIG_CONTIG_ALLOC */
1273 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1274 int nid
, nodemask_t
*nodemask
)
1278 #endif /* CONFIG_CONTIG_ALLOC */
1280 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1281 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1282 int nid
, nodemask_t
*nodemask
)
1286 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1287 static inline void destroy_compound_gigantic_page(struct page
*page
,
1288 unsigned int order
) { }
1291 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1295 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1299 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1300 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1301 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1302 1 << PG_referenced
| 1 << PG_dirty
|
1303 1 << PG_active
| 1 << PG_private
|
1306 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1307 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page
), page
);
1308 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1309 set_page_refcounted(page
);
1310 if (hstate_is_gigantic(h
)) {
1312 * Temporarily drop the hugetlb_lock, because
1313 * we might block in free_gigantic_page().
1315 spin_unlock(&hugetlb_lock
);
1316 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1317 free_gigantic_page(page
, huge_page_order(h
));
1318 spin_lock(&hugetlb_lock
);
1320 __free_pages(page
, huge_page_order(h
));
1324 struct hstate
*size_to_hstate(unsigned long size
)
1328 for_each_hstate(h
) {
1329 if (huge_page_size(h
) == size
)
1336 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1337 * to hstate->hugepage_activelist.)
1339 * This function can be called for tail pages, but never returns true for them.
1341 bool page_huge_active(struct page
*page
)
1343 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1344 return PageHead(page
) && PagePrivate(&page
[1]);
1347 /* never called for tail page */
1348 static void set_page_huge_active(struct page
*page
)
1350 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1351 SetPagePrivate(&page
[1]);
1354 static void clear_page_huge_active(struct page
*page
)
1356 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1357 ClearPagePrivate(&page
[1]);
1361 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1364 static inline bool PageHugeTemporary(struct page
*page
)
1366 if (!PageHuge(page
))
1369 return (unsigned long)page
[2].mapping
== -1U;
1372 static inline void SetPageHugeTemporary(struct page
*page
)
1374 page
[2].mapping
= (void *)-1U;
1377 static inline void ClearPageHugeTemporary(struct page
*page
)
1379 page
[2].mapping
= NULL
;
1382 static void __free_huge_page(struct page
*page
)
1385 * Can't pass hstate in here because it is called from the
1386 * compound page destructor.
1388 struct hstate
*h
= page_hstate(page
);
1389 int nid
= page_to_nid(page
);
1390 struct hugepage_subpool
*spool
=
1391 (struct hugepage_subpool
*)page_private(page
);
1392 bool restore_reserve
;
1394 VM_BUG_ON_PAGE(page_count(page
), page
);
1395 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1397 set_page_private(page
, 0);
1398 page
->mapping
= NULL
;
1399 restore_reserve
= PagePrivate(page
);
1400 ClearPagePrivate(page
);
1403 * If PagePrivate() was set on page, page allocation consumed a
1404 * reservation. If the page was associated with a subpool, there
1405 * would have been a page reserved in the subpool before allocation
1406 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1407 * reservtion, do not call hugepage_subpool_put_pages() as this will
1408 * remove the reserved page from the subpool.
1410 if (!restore_reserve
) {
1412 * A return code of zero implies that the subpool will be
1413 * under its minimum size if the reservation is not restored
1414 * after page is free. Therefore, force restore_reserve
1417 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1418 restore_reserve
= true;
1421 spin_lock(&hugetlb_lock
);
1422 clear_page_huge_active(page
);
1423 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1424 pages_per_huge_page(h
), page
);
1425 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h
),
1426 pages_per_huge_page(h
), page
);
1427 if (restore_reserve
)
1428 h
->resv_huge_pages
++;
1430 if (PageHugeTemporary(page
)) {
1431 list_del(&page
->lru
);
1432 ClearPageHugeTemporary(page
);
1433 update_and_free_page(h
, page
);
1434 } else if (h
->surplus_huge_pages_node
[nid
]) {
1435 /* remove the page from active list */
1436 list_del(&page
->lru
);
1437 update_and_free_page(h
, page
);
1438 h
->surplus_huge_pages
--;
1439 h
->surplus_huge_pages_node
[nid
]--;
1441 arch_clear_hugepage_flags(page
);
1442 enqueue_huge_page(h
, page
);
1444 spin_unlock(&hugetlb_lock
);
1448 * As free_huge_page() can be called from a non-task context, we have
1449 * to defer the actual freeing in a workqueue to prevent potential
1450 * hugetlb_lock deadlock.
1452 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1453 * be freed and frees them one-by-one. As the page->mapping pointer is
1454 * going to be cleared in __free_huge_page() anyway, it is reused as the
1455 * llist_node structure of a lockless linked list of huge pages to be freed.
1457 static LLIST_HEAD(hpage_freelist
);
1459 static void free_hpage_workfn(struct work_struct
*work
)
1461 struct llist_node
*node
;
1464 node
= llist_del_all(&hpage_freelist
);
1467 page
= container_of((struct address_space
**)node
,
1468 struct page
, mapping
);
1470 __free_huge_page(page
);
1473 static DECLARE_WORK(free_hpage_work
, free_hpage_workfn
);
1475 void free_huge_page(struct page
*page
)
1478 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1482 * Only call schedule_work() if hpage_freelist is previously
1483 * empty. Otherwise, schedule_work() had been called but the
1484 * workfn hasn't retrieved the list yet.
1486 if (llist_add((struct llist_node
*)&page
->mapping
,
1488 schedule_work(&free_hpage_work
);
1492 __free_huge_page(page
);
1495 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1497 INIT_LIST_HEAD(&page
->lru
);
1498 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1499 spin_lock(&hugetlb_lock
);
1500 set_hugetlb_cgroup(page
, NULL
);
1501 set_hugetlb_cgroup_rsvd(page
, NULL
);
1503 h
->nr_huge_pages_node
[nid
]++;
1504 spin_unlock(&hugetlb_lock
);
1507 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1510 int nr_pages
= 1 << order
;
1511 struct page
*p
= page
+ 1;
1513 /* we rely on prep_new_huge_page to set the destructor */
1514 set_compound_order(page
, order
);
1515 __ClearPageReserved(page
);
1516 __SetPageHead(page
);
1517 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1519 * For gigantic hugepages allocated through bootmem at
1520 * boot, it's safer to be consistent with the not-gigantic
1521 * hugepages and clear the PG_reserved bit from all tail pages
1522 * too. Otherwse drivers using get_user_pages() to access tail
1523 * pages may get the reference counting wrong if they see
1524 * PG_reserved set on a tail page (despite the head page not
1525 * having PG_reserved set). Enforcing this consistency between
1526 * head and tail pages allows drivers to optimize away a check
1527 * on the head page when they need know if put_page() is needed
1528 * after get_user_pages().
1530 __ClearPageReserved(p
);
1531 set_page_count(p
, 0);
1532 set_compound_head(p
, page
);
1534 atomic_set(compound_mapcount_ptr(page
), -1);
1536 if (hpage_pincount_available(page
))
1537 atomic_set(compound_pincount_ptr(page
), 0);
1541 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1542 * transparent huge pages. See the PageTransHuge() documentation for more
1545 int PageHuge(struct page
*page
)
1547 if (!PageCompound(page
))
1550 page
= compound_head(page
);
1551 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1553 EXPORT_SYMBOL_GPL(PageHuge
);
1556 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1557 * normal or transparent huge pages.
1559 int PageHeadHuge(struct page
*page_head
)
1561 if (!PageHead(page_head
))
1564 return page_head
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1568 * Find address_space associated with hugetlbfs page.
1569 * Upon entry page is locked and page 'was' mapped although mapped state
1570 * could change. If necessary, use anon_vma to find vma and associated
1571 * address space. The returned mapping may be stale, but it can not be
1572 * invalid as page lock (which is held) is required to destroy mapping.
1574 static struct address_space
*_get_hugetlb_page_mapping(struct page
*hpage
)
1576 struct anon_vma
*anon_vma
;
1577 pgoff_t pgoff_start
, pgoff_end
;
1578 struct anon_vma_chain
*avc
;
1579 struct address_space
*mapping
= page_mapping(hpage
);
1581 /* Simple file based mapping */
1586 * Even anonymous hugetlbfs mappings are associated with an
1587 * underlying hugetlbfs file (see hugetlb_file_setup in mmap
1588 * code). Find a vma associated with the anonymous vma, and
1589 * use the file pointer to get address_space.
1591 anon_vma
= page_lock_anon_vma_read(hpage
);
1593 return mapping
; /* NULL */
1595 /* Use first found vma */
1596 pgoff_start
= page_to_pgoff(hpage
);
1597 pgoff_end
= pgoff_start
+ hpage_nr_pages(hpage
) - 1;
1598 anon_vma_interval_tree_foreach(avc
, &anon_vma
->rb_root
,
1599 pgoff_start
, pgoff_end
) {
1600 struct vm_area_struct
*vma
= avc
->vma
;
1602 mapping
= vma
->vm_file
->f_mapping
;
1606 anon_vma_unlock_read(anon_vma
);
1611 * Find and lock address space (mapping) in write mode.
1613 * Upon entry, the page is locked which allows us to find the mapping
1614 * even in the case of an anon page. However, locking order dictates
1615 * the i_mmap_rwsem be acquired BEFORE the page lock. This is hugetlbfs
1616 * specific. So, we first try to lock the sema while still holding the
1617 * page lock. If this works, great! If not, then we need to drop the
1618 * page lock and then acquire i_mmap_rwsem and reacquire page lock. Of
1619 * course, need to revalidate state along the way.
1621 struct address_space
*hugetlb_page_mapping_lock_write(struct page
*hpage
)
1623 struct address_space
*mapping
, *mapping2
;
1625 mapping
= _get_hugetlb_page_mapping(hpage
);
1631 * If no contention, take lock and return
1633 if (i_mmap_trylock_write(mapping
))
1637 * Must drop page lock and wait on mapping sema.
1638 * Note: Once page lock is dropped, mapping could become invalid.
1639 * As a hack, increase map count until we lock page again.
1641 atomic_inc(&hpage
->_mapcount
);
1643 i_mmap_lock_write(mapping
);
1645 atomic_add_negative(-1, &hpage
->_mapcount
);
1647 /* verify page is still mapped */
1648 if (!page_mapped(hpage
)) {
1649 i_mmap_unlock_write(mapping
);
1654 * Get address space again and verify it is the same one
1655 * we locked. If not, drop lock and retry.
1657 mapping2
= _get_hugetlb_page_mapping(hpage
);
1658 if (mapping2
!= mapping
) {
1659 i_mmap_unlock_write(mapping
);
1667 pgoff_t
__basepage_index(struct page
*page
)
1669 struct page
*page_head
= compound_head(page
);
1670 pgoff_t index
= page_index(page_head
);
1671 unsigned long compound_idx
;
1673 if (!PageHuge(page_head
))
1674 return page_index(page
);
1676 if (compound_order(page_head
) >= MAX_ORDER
)
1677 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1679 compound_idx
= page
- page_head
;
1681 return (index
<< compound_order(page_head
)) + compound_idx
;
1684 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1685 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1686 nodemask_t
*node_alloc_noretry
)
1688 int order
= huge_page_order(h
);
1690 bool alloc_try_hard
= true;
1693 * By default we always try hard to allocate the page with
1694 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1695 * a loop (to adjust global huge page counts) and previous allocation
1696 * failed, do not continue to try hard on the same node. Use the
1697 * node_alloc_noretry bitmap to manage this state information.
1699 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1700 alloc_try_hard
= false;
1701 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1703 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1704 if (nid
== NUMA_NO_NODE
)
1705 nid
= numa_mem_id();
1706 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1708 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1710 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1713 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1714 * indicates an overall state change. Clear bit so that we resume
1715 * normal 'try hard' allocations.
1717 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1718 node_clear(nid
, *node_alloc_noretry
);
1721 * If we tried hard to get a page but failed, set bit so that
1722 * subsequent attempts will not try as hard until there is an
1723 * overall state change.
1725 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1726 node_set(nid
, *node_alloc_noretry
);
1732 * Common helper to allocate a fresh hugetlb page. All specific allocators
1733 * should use this function to get new hugetlb pages
1735 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1736 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1737 nodemask_t
*node_alloc_noretry
)
1741 if (hstate_is_gigantic(h
))
1742 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1744 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1745 nid
, nmask
, node_alloc_noretry
);
1749 if (hstate_is_gigantic(h
))
1750 prep_compound_gigantic_page(page
, huge_page_order(h
));
1751 prep_new_huge_page(h
, page
, page_to_nid(page
));
1757 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1760 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1761 nodemask_t
*node_alloc_noretry
)
1765 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1767 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1768 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1769 node_alloc_noretry
);
1777 put_page(page
); /* free it into the hugepage allocator */
1783 * Free huge page from pool from next node to free.
1784 * Attempt to keep persistent huge pages more or less
1785 * balanced over allowed nodes.
1786 * Called with hugetlb_lock locked.
1788 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1794 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1796 * If we're returning unused surplus pages, only examine
1797 * nodes with surplus pages.
1799 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1800 !list_empty(&h
->hugepage_freelists
[node
])) {
1802 list_entry(h
->hugepage_freelists
[node
].next
,
1804 list_del(&page
->lru
);
1805 h
->free_huge_pages
--;
1806 h
->free_huge_pages_node
[node
]--;
1808 h
->surplus_huge_pages
--;
1809 h
->surplus_huge_pages_node
[node
]--;
1811 update_and_free_page(h
, page
);
1821 * Dissolve a given free hugepage into free buddy pages. This function does
1822 * nothing for in-use hugepages and non-hugepages.
1823 * This function returns values like below:
1825 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1826 * (allocated or reserved.)
1827 * 0: successfully dissolved free hugepages or the page is not a
1828 * hugepage (considered as already dissolved)
1830 int dissolve_free_huge_page(struct page
*page
)
1834 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1835 if (!PageHuge(page
))
1838 spin_lock(&hugetlb_lock
);
1839 if (!PageHuge(page
)) {
1844 if (!page_count(page
)) {
1845 struct page
*head
= compound_head(page
);
1846 struct hstate
*h
= page_hstate(head
);
1847 int nid
= page_to_nid(head
);
1848 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1851 * Move PageHWPoison flag from head page to the raw error page,
1852 * which makes any subpages rather than the error page reusable.
1854 if (PageHWPoison(head
) && page
!= head
) {
1855 SetPageHWPoison(page
);
1856 ClearPageHWPoison(head
);
1858 list_del(&head
->lru
);
1859 h
->free_huge_pages
--;
1860 h
->free_huge_pages_node
[nid
]--;
1861 h
->max_huge_pages
--;
1862 update_and_free_page(h
, head
);
1866 spin_unlock(&hugetlb_lock
);
1871 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1872 * make specified memory blocks removable from the system.
1873 * Note that this will dissolve a free gigantic hugepage completely, if any
1874 * part of it lies within the given range.
1875 * Also note that if dissolve_free_huge_page() returns with an error, all
1876 * free hugepages that were dissolved before that error are lost.
1878 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1884 if (!hugepages_supported())
1887 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1888 page
= pfn_to_page(pfn
);
1889 rc
= dissolve_free_huge_page(page
);
1898 * Allocates a fresh surplus page from the page allocator.
1900 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1901 int nid
, nodemask_t
*nmask
)
1903 struct page
*page
= NULL
;
1905 if (hstate_is_gigantic(h
))
1908 spin_lock(&hugetlb_lock
);
1909 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1911 spin_unlock(&hugetlb_lock
);
1913 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1917 spin_lock(&hugetlb_lock
);
1919 * We could have raced with the pool size change.
1920 * Double check that and simply deallocate the new page
1921 * if we would end up overcommiting the surpluses. Abuse
1922 * temporary page to workaround the nasty free_huge_page
1925 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1926 SetPageHugeTemporary(page
);
1927 spin_unlock(&hugetlb_lock
);
1931 h
->surplus_huge_pages
++;
1932 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1936 spin_unlock(&hugetlb_lock
);
1941 struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1942 int nid
, nodemask_t
*nmask
)
1946 if (hstate_is_gigantic(h
))
1949 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1954 * We do not account these pages as surplus because they are only
1955 * temporary and will be released properly on the last reference
1957 SetPageHugeTemporary(page
);
1963 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1966 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1967 struct vm_area_struct
*vma
, unsigned long addr
)
1970 struct mempolicy
*mpol
;
1971 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1973 nodemask_t
*nodemask
;
1975 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1976 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1977 mpol_cond_put(mpol
);
1982 /* page migration callback function */
1983 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1985 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1986 struct page
*page
= NULL
;
1988 if (nid
!= NUMA_NO_NODE
)
1989 gfp_mask
|= __GFP_THISNODE
;
1991 spin_lock(&hugetlb_lock
);
1992 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1993 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1994 spin_unlock(&hugetlb_lock
);
1997 page
= alloc_migrate_huge_page(h
, gfp_mask
, nid
, NULL
);
2002 /* page migration callback function */
2003 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
2006 gfp_t gfp_mask
= htlb_alloc_mask(h
);
2008 spin_lock(&hugetlb_lock
);
2009 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
2012 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
2014 spin_unlock(&hugetlb_lock
);
2018 spin_unlock(&hugetlb_lock
);
2020 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
2023 /* mempolicy aware migration callback */
2024 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
2025 unsigned long address
)
2027 struct mempolicy
*mpol
;
2028 nodemask_t
*nodemask
;
2033 gfp_mask
= htlb_alloc_mask(h
);
2034 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
2035 page
= alloc_huge_page_nodemask(h
, node
, nodemask
);
2036 mpol_cond_put(mpol
);
2042 * Increase the hugetlb pool such that it can accommodate a reservation
2045 static int gather_surplus_pages(struct hstate
*h
, int delta
)
2046 __must_hold(&hugetlb_lock
)
2048 struct list_head surplus_list
;
2049 struct page
*page
, *tmp
;
2051 int needed
, allocated
;
2052 bool alloc_ok
= true;
2054 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
2056 h
->resv_huge_pages
+= delta
;
2061 INIT_LIST_HEAD(&surplus_list
);
2065 spin_unlock(&hugetlb_lock
);
2066 for (i
= 0; i
< needed
; i
++) {
2067 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
2068 NUMA_NO_NODE
, NULL
);
2073 list_add(&page
->lru
, &surplus_list
);
2079 * After retaking hugetlb_lock, we need to recalculate 'needed'
2080 * because either resv_huge_pages or free_huge_pages may have changed.
2082 spin_lock(&hugetlb_lock
);
2083 needed
= (h
->resv_huge_pages
+ delta
) -
2084 (h
->free_huge_pages
+ allocated
);
2089 * We were not able to allocate enough pages to
2090 * satisfy the entire reservation so we free what
2091 * we've allocated so far.
2096 * The surplus_list now contains _at_least_ the number of extra pages
2097 * needed to accommodate the reservation. Add the appropriate number
2098 * of pages to the hugetlb pool and free the extras back to the buddy
2099 * allocator. Commit the entire reservation here to prevent another
2100 * process from stealing the pages as they are added to the pool but
2101 * before they are reserved.
2103 needed
+= allocated
;
2104 h
->resv_huge_pages
+= delta
;
2107 /* Free the needed pages to the hugetlb pool */
2108 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
2112 * This page is now managed by the hugetlb allocator and has
2113 * no users -- drop the buddy allocator's reference.
2115 put_page_testzero(page
);
2116 VM_BUG_ON_PAGE(page_count(page
), page
);
2117 enqueue_huge_page(h
, page
);
2120 spin_unlock(&hugetlb_lock
);
2122 /* Free unnecessary surplus pages to the buddy allocator */
2123 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
2125 spin_lock(&hugetlb_lock
);
2131 * This routine has two main purposes:
2132 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2133 * in unused_resv_pages. This corresponds to the prior adjustments made
2134 * to the associated reservation map.
2135 * 2) Free any unused surplus pages that may have been allocated to satisfy
2136 * the reservation. As many as unused_resv_pages may be freed.
2138 * Called with hugetlb_lock held. However, the lock could be dropped (and
2139 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2140 * we must make sure nobody else can claim pages we are in the process of
2141 * freeing. Do this by ensuring resv_huge_page always is greater than the
2142 * number of huge pages we plan to free when dropping the lock.
2144 static void return_unused_surplus_pages(struct hstate
*h
,
2145 unsigned long unused_resv_pages
)
2147 unsigned long nr_pages
;
2149 /* Cannot return gigantic pages currently */
2150 if (hstate_is_gigantic(h
))
2154 * Part (or even all) of the reservation could have been backed
2155 * by pre-allocated pages. Only free surplus pages.
2157 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
2160 * We want to release as many surplus pages as possible, spread
2161 * evenly across all nodes with memory. Iterate across these nodes
2162 * until we can no longer free unreserved surplus pages. This occurs
2163 * when the nodes with surplus pages have no free pages.
2164 * free_pool_huge_page() will balance the the freed pages across the
2165 * on-line nodes with memory and will handle the hstate accounting.
2167 * Note that we decrement resv_huge_pages as we free the pages. If
2168 * we drop the lock, resv_huge_pages will still be sufficiently large
2169 * to cover subsequent pages we may free.
2171 while (nr_pages
--) {
2172 h
->resv_huge_pages
--;
2173 unused_resv_pages
--;
2174 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
2176 cond_resched_lock(&hugetlb_lock
);
2180 /* Fully uncommit the reservation */
2181 h
->resv_huge_pages
-= unused_resv_pages
;
2186 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2187 * are used by the huge page allocation routines to manage reservations.
2189 * vma_needs_reservation is called to determine if the huge page at addr
2190 * within the vma has an associated reservation. If a reservation is
2191 * needed, the value 1 is returned. The caller is then responsible for
2192 * managing the global reservation and subpool usage counts. After
2193 * the huge page has been allocated, vma_commit_reservation is called
2194 * to add the page to the reservation map. If the page allocation fails,
2195 * the reservation must be ended instead of committed. vma_end_reservation
2196 * is called in such cases.
2198 * In the normal case, vma_commit_reservation returns the same value
2199 * as the preceding vma_needs_reservation call. The only time this
2200 * is not the case is if a reserve map was changed between calls. It
2201 * is the responsibility of the caller to notice the difference and
2202 * take appropriate action.
2204 * vma_add_reservation is used in error paths where a reservation must
2205 * be restored when a newly allocated huge page must be freed. It is
2206 * to be called after calling vma_needs_reservation to determine if a
2207 * reservation exists.
2209 enum vma_resv_mode
{
2215 static long __vma_reservation_common(struct hstate
*h
,
2216 struct vm_area_struct
*vma
, unsigned long addr
,
2217 enum vma_resv_mode mode
)
2219 struct resv_map
*resv
;
2222 long dummy_out_regions_needed
;
2224 resv
= vma_resv_map(vma
);
2228 idx
= vma_hugecache_offset(h
, vma
, addr
);
2230 case VMA_NEEDS_RESV
:
2231 ret
= region_chg(resv
, idx
, idx
+ 1, &dummy_out_regions_needed
);
2232 /* We assume that vma_reservation_* routines always operate on
2233 * 1 page, and that adding to resv map a 1 page entry can only
2234 * ever require 1 region.
2236 VM_BUG_ON(dummy_out_regions_needed
!= 1);
2238 case VMA_COMMIT_RESV
:
2239 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2240 /* region_add calls of range 1 should never fail. */
2244 region_abort(resv
, idx
, idx
+ 1, 1);
2248 if (vma
->vm_flags
& VM_MAYSHARE
) {
2249 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2250 /* region_add calls of range 1 should never fail. */
2253 region_abort(resv
, idx
, idx
+ 1, 1);
2254 ret
= region_del(resv
, idx
, idx
+ 1);
2261 if (vma
->vm_flags
& VM_MAYSHARE
)
2263 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
2265 * In most cases, reserves always exist for private mappings.
2266 * However, a file associated with mapping could have been
2267 * hole punched or truncated after reserves were consumed.
2268 * As subsequent fault on such a range will not use reserves.
2269 * Subtle - The reserve map for private mappings has the
2270 * opposite meaning than that of shared mappings. If NO
2271 * entry is in the reserve map, it means a reservation exists.
2272 * If an entry exists in the reserve map, it means the
2273 * reservation has already been consumed. As a result, the
2274 * return value of this routine is the opposite of the
2275 * value returned from reserve map manipulation routines above.
2283 return ret
< 0 ? ret
: 0;
2286 static long vma_needs_reservation(struct hstate
*h
,
2287 struct vm_area_struct
*vma
, unsigned long addr
)
2289 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
2292 static long vma_commit_reservation(struct hstate
*h
,
2293 struct vm_area_struct
*vma
, unsigned long addr
)
2295 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
2298 static void vma_end_reservation(struct hstate
*h
,
2299 struct vm_area_struct
*vma
, unsigned long addr
)
2301 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
2304 static long vma_add_reservation(struct hstate
*h
,
2305 struct vm_area_struct
*vma
, unsigned long addr
)
2307 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
2311 * This routine is called to restore a reservation on error paths. In the
2312 * specific error paths, a huge page was allocated (via alloc_huge_page)
2313 * and is about to be freed. If a reservation for the page existed,
2314 * alloc_huge_page would have consumed the reservation and set PagePrivate
2315 * in the newly allocated page. When the page is freed via free_huge_page,
2316 * the global reservation count will be incremented if PagePrivate is set.
2317 * However, free_huge_page can not adjust the reserve map. Adjust the
2318 * reserve map here to be consistent with global reserve count adjustments
2319 * to be made by free_huge_page.
2321 static void restore_reserve_on_error(struct hstate
*h
,
2322 struct vm_area_struct
*vma
, unsigned long address
,
2325 if (unlikely(PagePrivate(page
))) {
2326 long rc
= vma_needs_reservation(h
, vma
, address
);
2328 if (unlikely(rc
< 0)) {
2330 * Rare out of memory condition in reserve map
2331 * manipulation. Clear PagePrivate so that
2332 * global reserve count will not be incremented
2333 * by free_huge_page. This will make it appear
2334 * as though the reservation for this page was
2335 * consumed. This may prevent the task from
2336 * faulting in the page at a later time. This
2337 * is better than inconsistent global huge page
2338 * accounting of reserve counts.
2340 ClearPagePrivate(page
);
2342 rc
= vma_add_reservation(h
, vma
, address
);
2343 if (unlikely(rc
< 0))
2345 * See above comment about rare out of
2348 ClearPagePrivate(page
);
2350 vma_end_reservation(h
, vma
, address
);
2354 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2355 unsigned long addr
, int avoid_reserve
)
2357 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2358 struct hstate
*h
= hstate_vma(vma
);
2360 long map_chg
, map_commit
;
2363 struct hugetlb_cgroup
*h_cg
;
2364 bool deferred_reserve
;
2366 idx
= hstate_index(h
);
2368 * Examine the region/reserve map to determine if the process
2369 * has a reservation for the page to be allocated. A return
2370 * code of zero indicates a reservation exists (no change).
2372 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2374 return ERR_PTR(-ENOMEM
);
2377 * Processes that did not create the mapping will have no
2378 * reserves as indicated by the region/reserve map. Check
2379 * that the allocation will not exceed the subpool limit.
2380 * Allocations for MAP_NORESERVE mappings also need to be
2381 * checked against any subpool limit.
2383 if (map_chg
|| avoid_reserve
) {
2384 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2386 vma_end_reservation(h
, vma
, addr
);
2387 return ERR_PTR(-ENOSPC
);
2391 * Even though there was no reservation in the region/reserve
2392 * map, there could be reservations associated with the
2393 * subpool that can be used. This would be indicated if the
2394 * return value of hugepage_subpool_get_pages() is zero.
2395 * However, if avoid_reserve is specified we still avoid even
2396 * the subpool reservations.
2402 /* If this allocation is not consuming a reservation, charge it now.
2404 deferred_reserve
= map_chg
|| avoid_reserve
|| !vma_resv_map(vma
);
2405 if (deferred_reserve
) {
2406 ret
= hugetlb_cgroup_charge_cgroup_rsvd(
2407 idx
, pages_per_huge_page(h
), &h_cg
);
2409 goto out_subpool_put
;
2412 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2414 goto out_uncharge_cgroup_reservation
;
2416 spin_lock(&hugetlb_lock
);
2418 * glb_chg is passed to indicate whether or not a page must be taken
2419 * from the global free pool (global change). gbl_chg == 0 indicates
2420 * a reservation exists for the allocation.
2422 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2424 spin_unlock(&hugetlb_lock
);
2425 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2427 goto out_uncharge_cgroup
;
2428 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2429 SetPagePrivate(page
);
2430 h
->resv_huge_pages
--;
2432 spin_lock(&hugetlb_lock
);
2433 list_move(&page
->lru
, &h
->hugepage_activelist
);
2436 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2437 /* If allocation is not consuming a reservation, also store the
2438 * hugetlb_cgroup pointer on the page.
2440 if (deferred_reserve
) {
2441 hugetlb_cgroup_commit_charge_rsvd(idx
, pages_per_huge_page(h
),
2445 spin_unlock(&hugetlb_lock
);
2447 set_page_private(page
, (unsigned long)spool
);
2449 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2450 if (unlikely(map_chg
> map_commit
)) {
2452 * The page was added to the reservation map between
2453 * vma_needs_reservation and vma_commit_reservation.
2454 * This indicates a race with hugetlb_reserve_pages.
2455 * Adjust for the subpool count incremented above AND
2456 * in hugetlb_reserve_pages for the same page. Also,
2457 * the reservation count added in hugetlb_reserve_pages
2458 * no longer applies.
2462 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2463 hugetlb_acct_memory(h
, -rsv_adjust
);
2467 out_uncharge_cgroup
:
2468 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2469 out_uncharge_cgroup_reservation
:
2470 if (deferred_reserve
)
2471 hugetlb_cgroup_uncharge_cgroup_rsvd(idx
, pages_per_huge_page(h
),
2474 if (map_chg
|| avoid_reserve
)
2475 hugepage_subpool_put_pages(spool
, 1);
2476 vma_end_reservation(h
, vma
, addr
);
2477 return ERR_PTR(-ENOSPC
);
2480 int alloc_bootmem_huge_page(struct hstate
*h
)
2481 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2482 int __alloc_bootmem_huge_page(struct hstate
*h
)
2484 struct huge_bootmem_page
*m
;
2487 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2490 addr
= memblock_alloc_try_nid_raw(
2491 huge_page_size(h
), huge_page_size(h
),
2492 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2495 * Use the beginning of the huge page to store the
2496 * huge_bootmem_page struct (until gather_bootmem
2497 * puts them into the mem_map).
2506 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2507 /* Put them into a private list first because mem_map is not up yet */
2508 INIT_LIST_HEAD(&m
->list
);
2509 list_add(&m
->list
, &huge_boot_pages
);
2514 static void __init
prep_compound_huge_page(struct page
*page
,
2517 if (unlikely(order
> (MAX_ORDER
- 1)))
2518 prep_compound_gigantic_page(page
, order
);
2520 prep_compound_page(page
, order
);
2523 /* Put bootmem huge pages into the standard lists after mem_map is up */
2524 static void __init
gather_bootmem_prealloc(void)
2526 struct huge_bootmem_page
*m
;
2528 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2529 struct page
*page
= virt_to_page(m
);
2530 struct hstate
*h
= m
->hstate
;
2532 WARN_ON(page_count(page
) != 1);
2533 prep_compound_huge_page(page
, h
->order
);
2534 WARN_ON(PageReserved(page
));
2535 prep_new_huge_page(h
, page
, page_to_nid(page
));
2536 put_page(page
); /* free it into the hugepage allocator */
2539 * If we had gigantic hugepages allocated at boot time, we need
2540 * to restore the 'stolen' pages to totalram_pages in order to
2541 * fix confusing memory reports from free(1) and another
2542 * side-effects, like CommitLimit going negative.
2544 if (hstate_is_gigantic(h
))
2545 adjust_managed_page_count(page
, 1 << h
->order
);
2550 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2553 nodemask_t
*node_alloc_noretry
;
2555 if (!hstate_is_gigantic(h
)) {
2557 * Bit mask controlling how hard we retry per-node allocations.
2558 * Ignore errors as lower level routines can deal with
2559 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2560 * time, we are likely in bigger trouble.
2562 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2565 /* allocations done at boot time */
2566 node_alloc_noretry
= NULL
;
2569 /* bit mask controlling how hard we retry per-node allocations */
2570 if (node_alloc_noretry
)
2571 nodes_clear(*node_alloc_noretry
);
2573 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2574 if (hstate_is_gigantic(h
)) {
2575 if (IS_ENABLED(CONFIG_CMA
) && hugetlb_cma
[0]) {
2576 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2579 if (!alloc_bootmem_huge_page(h
))
2581 } else if (!alloc_pool_huge_page(h
,
2582 &node_states
[N_MEMORY
],
2583 node_alloc_noretry
))
2587 if (i
< h
->max_huge_pages
) {
2590 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2591 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2592 h
->max_huge_pages
, buf
, i
);
2593 h
->max_huge_pages
= i
;
2596 kfree(node_alloc_noretry
);
2599 static void __init
hugetlb_init_hstates(void)
2603 for_each_hstate(h
) {
2604 if (minimum_order
> huge_page_order(h
))
2605 minimum_order
= huge_page_order(h
);
2607 /* oversize hugepages were init'ed in early boot */
2608 if (!hstate_is_gigantic(h
))
2609 hugetlb_hstate_alloc_pages(h
);
2611 VM_BUG_ON(minimum_order
== UINT_MAX
);
2614 static void __init
report_hugepages(void)
2618 for_each_hstate(h
) {
2621 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2622 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2623 buf
, h
->free_huge_pages
);
2627 #ifdef CONFIG_HIGHMEM
2628 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2629 nodemask_t
*nodes_allowed
)
2633 if (hstate_is_gigantic(h
))
2636 for_each_node_mask(i
, *nodes_allowed
) {
2637 struct page
*page
, *next
;
2638 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2639 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2640 if (count
>= h
->nr_huge_pages
)
2642 if (PageHighMem(page
))
2644 list_del(&page
->lru
);
2645 update_and_free_page(h
, page
);
2646 h
->free_huge_pages
--;
2647 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2652 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2653 nodemask_t
*nodes_allowed
)
2659 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2660 * balanced by operating on them in a round-robin fashion.
2661 * Returns 1 if an adjustment was made.
2663 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2668 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2671 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2672 if (h
->surplus_huge_pages_node
[node
])
2676 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2677 if (h
->surplus_huge_pages_node
[node
] <
2678 h
->nr_huge_pages_node
[node
])
2685 h
->surplus_huge_pages
+= delta
;
2686 h
->surplus_huge_pages_node
[node
] += delta
;
2690 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2691 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2692 nodemask_t
*nodes_allowed
)
2694 unsigned long min_count
, ret
;
2695 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2698 * Bit mask controlling how hard we retry per-node allocations.
2699 * If we can not allocate the bit mask, do not attempt to allocate
2700 * the requested huge pages.
2702 if (node_alloc_noretry
)
2703 nodes_clear(*node_alloc_noretry
);
2707 spin_lock(&hugetlb_lock
);
2710 * Check for a node specific request.
2711 * Changing node specific huge page count may require a corresponding
2712 * change to the global count. In any case, the passed node mask
2713 * (nodes_allowed) will restrict alloc/free to the specified node.
2715 if (nid
!= NUMA_NO_NODE
) {
2716 unsigned long old_count
= count
;
2718 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2720 * User may have specified a large count value which caused the
2721 * above calculation to overflow. In this case, they wanted
2722 * to allocate as many huge pages as possible. Set count to
2723 * largest possible value to align with their intention.
2725 if (count
< old_count
)
2730 * Gigantic pages runtime allocation depend on the capability for large
2731 * page range allocation.
2732 * If the system does not provide this feature, return an error when
2733 * the user tries to allocate gigantic pages but let the user free the
2734 * boottime allocated gigantic pages.
2736 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2737 if (count
> persistent_huge_pages(h
)) {
2738 spin_unlock(&hugetlb_lock
);
2739 NODEMASK_FREE(node_alloc_noretry
);
2742 /* Fall through to decrease pool */
2746 * Increase the pool size
2747 * First take pages out of surplus state. Then make up the
2748 * remaining difference by allocating fresh huge pages.
2750 * We might race with alloc_surplus_huge_page() here and be unable
2751 * to convert a surplus huge page to a normal huge page. That is
2752 * not critical, though, it just means the overall size of the
2753 * pool might be one hugepage larger than it needs to be, but
2754 * within all the constraints specified by the sysctls.
2756 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2757 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2761 while (count
> persistent_huge_pages(h
)) {
2763 * If this allocation races such that we no longer need the
2764 * page, free_huge_page will handle it by freeing the page
2765 * and reducing the surplus.
2767 spin_unlock(&hugetlb_lock
);
2769 /* yield cpu to avoid soft lockup */
2772 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2773 node_alloc_noretry
);
2774 spin_lock(&hugetlb_lock
);
2778 /* Bail for signals. Probably ctrl-c from user */
2779 if (signal_pending(current
))
2784 * Decrease the pool size
2785 * First return free pages to the buddy allocator (being careful
2786 * to keep enough around to satisfy reservations). Then place
2787 * pages into surplus state as needed so the pool will shrink
2788 * to the desired size as pages become free.
2790 * By placing pages into the surplus state independent of the
2791 * overcommit value, we are allowing the surplus pool size to
2792 * exceed overcommit. There are few sane options here. Since
2793 * alloc_surplus_huge_page() is checking the global counter,
2794 * though, we'll note that we're not allowed to exceed surplus
2795 * and won't grow the pool anywhere else. Not until one of the
2796 * sysctls are changed, or the surplus pages go out of use.
2798 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2799 min_count
= max(count
, min_count
);
2800 try_to_free_low(h
, min_count
, nodes_allowed
);
2801 while (min_count
< persistent_huge_pages(h
)) {
2802 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2804 cond_resched_lock(&hugetlb_lock
);
2806 while (count
< persistent_huge_pages(h
)) {
2807 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2811 h
->max_huge_pages
= persistent_huge_pages(h
);
2812 spin_unlock(&hugetlb_lock
);
2814 NODEMASK_FREE(node_alloc_noretry
);
2819 #define HSTATE_ATTR_RO(_name) \
2820 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2822 #define HSTATE_ATTR(_name) \
2823 static struct kobj_attribute _name##_attr = \
2824 __ATTR(_name, 0644, _name##_show, _name##_store)
2826 static struct kobject
*hugepages_kobj
;
2827 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2829 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2831 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2835 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2836 if (hstate_kobjs
[i
] == kobj
) {
2838 *nidp
= NUMA_NO_NODE
;
2842 return kobj_to_node_hstate(kobj
, nidp
);
2845 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2846 struct kobj_attribute
*attr
, char *buf
)
2849 unsigned long nr_huge_pages
;
2852 h
= kobj_to_hstate(kobj
, &nid
);
2853 if (nid
== NUMA_NO_NODE
)
2854 nr_huge_pages
= h
->nr_huge_pages
;
2856 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2858 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2861 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2862 struct hstate
*h
, int nid
,
2863 unsigned long count
, size_t len
)
2866 nodemask_t nodes_allowed
, *n_mask
;
2868 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2871 if (nid
== NUMA_NO_NODE
) {
2873 * global hstate attribute
2875 if (!(obey_mempolicy
&&
2876 init_nodemask_of_mempolicy(&nodes_allowed
)))
2877 n_mask
= &node_states
[N_MEMORY
];
2879 n_mask
= &nodes_allowed
;
2882 * Node specific request. count adjustment happens in
2883 * set_max_huge_pages() after acquiring hugetlb_lock.
2885 init_nodemask_of_node(&nodes_allowed
, nid
);
2886 n_mask
= &nodes_allowed
;
2889 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2891 return err
? err
: len
;
2894 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2895 struct kobject
*kobj
, const char *buf
,
2899 unsigned long count
;
2903 err
= kstrtoul(buf
, 10, &count
);
2907 h
= kobj_to_hstate(kobj
, &nid
);
2908 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2911 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2912 struct kobj_attribute
*attr
, char *buf
)
2914 return nr_hugepages_show_common(kobj
, attr
, buf
);
2917 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2918 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2920 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2922 HSTATE_ATTR(nr_hugepages
);
2927 * hstate attribute for optionally mempolicy-based constraint on persistent
2928 * huge page alloc/free.
2930 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2931 struct kobj_attribute
*attr
, char *buf
)
2933 return nr_hugepages_show_common(kobj
, attr
, buf
);
2936 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2937 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2939 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2941 HSTATE_ATTR(nr_hugepages_mempolicy
);
2945 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2946 struct kobj_attribute
*attr
, char *buf
)
2948 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2949 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2952 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2953 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2956 unsigned long input
;
2957 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2959 if (hstate_is_gigantic(h
))
2962 err
= kstrtoul(buf
, 10, &input
);
2966 spin_lock(&hugetlb_lock
);
2967 h
->nr_overcommit_huge_pages
= input
;
2968 spin_unlock(&hugetlb_lock
);
2972 HSTATE_ATTR(nr_overcommit_hugepages
);
2974 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2975 struct kobj_attribute
*attr
, char *buf
)
2978 unsigned long free_huge_pages
;
2981 h
= kobj_to_hstate(kobj
, &nid
);
2982 if (nid
== NUMA_NO_NODE
)
2983 free_huge_pages
= h
->free_huge_pages
;
2985 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2987 return sprintf(buf
, "%lu\n", free_huge_pages
);
2989 HSTATE_ATTR_RO(free_hugepages
);
2991 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2992 struct kobj_attribute
*attr
, char *buf
)
2994 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2995 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2997 HSTATE_ATTR_RO(resv_hugepages
);
2999 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
3000 struct kobj_attribute
*attr
, char *buf
)
3003 unsigned long surplus_huge_pages
;
3006 h
= kobj_to_hstate(kobj
, &nid
);
3007 if (nid
== NUMA_NO_NODE
)
3008 surplus_huge_pages
= h
->surplus_huge_pages
;
3010 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
3012 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
3014 HSTATE_ATTR_RO(surplus_hugepages
);
3016 static struct attribute
*hstate_attrs
[] = {
3017 &nr_hugepages_attr
.attr
,
3018 &nr_overcommit_hugepages_attr
.attr
,
3019 &free_hugepages_attr
.attr
,
3020 &resv_hugepages_attr
.attr
,
3021 &surplus_hugepages_attr
.attr
,
3023 &nr_hugepages_mempolicy_attr
.attr
,
3028 static const struct attribute_group hstate_attr_group
= {
3029 .attrs
= hstate_attrs
,
3032 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
3033 struct kobject
**hstate_kobjs
,
3034 const struct attribute_group
*hstate_attr_group
)
3037 int hi
= hstate_index(h
);
3039 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
3040 if (!hstate_kobjs
[hi
])
3043 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
3045 kobject_put(hstate_kobjs
[hi
]);
3050 static void __init
hugetlb_sysfs_init(void)
3055 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
3056 if (!hugepages_kobj
)
3059 for_each_hstate(h
) {
3060 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
3061 hstate_kobjs
, &hstate_attr_group
);
3063 pr_err("HugeTLB: Unable to add hstate %s", h
->name
);
3070 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3071 * with node devices in node_devices[] using a parallel array. The array
3072 * index of a node device or _hstate == node id.
3073 * This is here to avoid any static dependency of the node device driver, in
3074 * the base kernel, on the hugetlb module.
3076 struct node_hstate
{
3077 struct kobject
*hugepages_kobj
;
3078 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
3080 static struct node_hstate node_hstates
[MAX_NUMNODES
];
3083 * A subset of global hstate attributes for node devices
3085 static struct attribute
*per_node_hstate_attrs
[] = {
3086 &nr_hugepages_attr
.attr
,
3087 &free_hugepages_attr
.attr
,
3088 &surplus_hugepages_attr
.attr
,
3092 static const struct attribute_group per_node_hstate_attr_group
= {
3093 .attrs
= per_node_hstate_attrs
,
3097 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3098 * Returns node id via non-NULL nidp.
3100 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3104 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
3105 struct node_hstate
*nhs
= &node_hstates
[nid
];
3107 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
3108 if (nhs
->hstate_kobjs
[i
] == kobj
) {
3120 * Unregister hstate attributes from a single node device.
3121 * No-op if no hstate attributes attached.
3123 static void hugetlb_unregister_node(struct node
*node
)
3126 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3128 if (!nhs
->hugepages_kobj
)
3129 return; /* no hstate attributes */
3131 for_each_hstate(h
) {
3132 int idx
= hstate_index(h
);
3133 if (nhs
->hstate_kobjs
[idx
]) {
3134 kobject_put(nhs
->hstate_kobjs
[idx
]);
3135 nhs
->hstate_kobjs
[idx
] = NULL
;
3139 kobject_put(nhs
->hugepages_kobj
);
3140 nhs
->hugepages_kobj
= NULL
;
3145 * Register hstate attributes for a single node device.
3146 * No-op if attributes already registered.
3148 static void hugetlb_register_node(struct node
*node
)
3151 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3154 if (nhs
->hugepages_kobj
)
3155 return; /* already allocated */
3157 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
3159 if (!nhs
->hugepages_kobj
)
3162 for_each_hstate(h
) {
3163 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
3165 &per_node_hstate_attr_group
);
3167 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3168 h
->name
, node
->dev
.id
);
3169 hugetlb_unregister_node(node
);
3176 * hugetlb init time: register hstate attributes for all registered node
3177 * devices of nodes that have memory. All on-line nodes should have
3178 * registered their associated device by this time.
3180 static void __init
hugetlb_register_all_nodes(void)
3184 for_each_node_state(nid
, N_MEMORY
) {
3185 struct node
*node
= node_devices
[nid
];
3186 if (node
->dev
.id
== nid
)
3187 hugetlb_register_node(node
);
3191 * Let the node device driver know we're here so it can
3192 * [un]register hstate attributes on node hotplug.
3194 register_hugetlbfs_with_node(hugetlb_register_node
,
3195 hugetlb_unregister_node
);
3197 #else /* !CONFIG_NUMA */
3199 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3207 static void hugetlb_register_all_nodes(void) { }
3211 static int __init
hugetlb_init(void)
3215 if (!hugepages_supported()) {
3216 if (hugetlb_max_hstate
|| default_hstate_max_huge_pages
)
3217 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3222 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3223 * architectures depend on setup being done here.
3225 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
3226 if (!parsed_default_hugepagesz
) {
3228 * If we did not parse a default huge page size, set
3229 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3230 * number of huge pages for this default size was implicitly
3231 * specified, set that here as well.
3232 * Note that the implicit setting will overwrite an explicit
3233 * setting. A warning will be printed in this case.
3235 default_hstate_idx
= hstate_index(size_to_hstate(HPAGE_SIZE
));
3236 if (default_hstate_max_huge_pages
) {
3237 if (default_hstate
.max_huge_pages
) {
3240 string_get_size(huge_page_size(&default_hstate
),
3241 1, STRING_UNITS_2
, buf
, 32);
3242 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3243 default_hstate
.max_huge_pages
, buf
);
3244 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3245 default_hstate_max_huge_pages
);
3247 default_hstate
.max_huge_pages
=
3248 default_hstate_max_huge_pages
;
3252 hugetlb_cma_check();
3253 hugetlb_init_hstates();
3254 gather_bootmem_prealloc();
3257 hugetlb_sysfs_init();
3258 hugetlb_register_all_nodes();
3259 hugetlb_cgroup_file_init();
3262 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
3264 num_fault_mutexes
= 1;
3266 hugetlb_fault_mutex_table
=
3267 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
3269 BUG_ON(!hugetlb_fault_mutex_table
);
3271 for (i
= 0; i
< num_fault_mutexes
; i
++)
3272 mutex_init(&hugetlb_fault_mutex_table
[i
]);
3275 subsys_initcall(hugetlb_init
);
3277 /* Overwritten by architectures with more huge page sizes */
3278 bool __init
__attribute((weak
)) arch_hugetlb_valid_size(unsigned long size
)
3280 return size
== HPAGE_SIZE
;
3283 void __init
hugetlb_add_hstate(unsigned int order
)
3288 if (size_to_hstate(PAGE_SIZE
<< order
)) {
3291 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
3293 h
= &hstates
[hugetlb_max_hstate
++];
3295 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
3296 h
->nr_huge_pages
= 0;
3297 h
->free_huge_pages
= 0;
3298 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
3299 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
3300 INIT_LIST_HEAD(&h
->hugepage_activelist
);
3301 h
->next_nid_to_alloc
= first_memory_node
;
3302 h
->next_nid_to_free
= first_memory_node
;
3303 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
3304 huge_page_size(h
)/1024);
3310 * hugepages command line processing
3311 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3312 * specification. If not, ignore the hugepages value. hugepages can also
3313 * be the first huge page command line option in which case it implicitly
3314 * specifies the number of huge pages for the default size.
3316 static int __init
hugepages_setup(char *s
)
3319 static unsigned long *last_mhp
;
3321 if (!parsed_valid_hugepagesz
) {
3322 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s
);
3323 parsed_valid_hugepagesz
= true;
3328 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3329 * yet, so this hugepages= parameter goes to the "default hstate".
3330 * Otherwise, it goes with the previously parsed hugepagesz or
3331 * default_hugepagesz.
3333 else if (!hugetlb_max_hstate
)
3334 mhp
= &default_hstate_max_huge_pages
;
3336 mhp
= &parsed_hstate
->max_huge_pages
;
3338 if (mhp
== last_mhp
) {
3339 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s
);
3343 if (sscanf(s
, "%lu", mhp
) <= 0)
3347 * Global state is always initialized later in hugetlb_init.
3348 * But we need to allocate >= MAX_ORDER hstates here early to still
3349 * use the bootmem allocator.
3351 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
3352 hugetlb_hstate_alloc_pages(parsed_hstate
);
3358 __setup("hugepages=", hugepages_setup
);
3361 * hugepagesz command line processing
3362 * A specific huge page size can only be specified once with hugepagesz.
3363 * hugepagesz is followed by hugepages on the command line. The global
3364 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3365 * hugepagesz argument was valid.
3367 static int __init
hugepagesz_setup(char *s
)
3372 parsed_valid_hugepagesz
= false;
3373 size
= (unsigned long)memparse(s
, NULL
);
3375 if (!arch_hugetlb_valid_size(size
)) {
3376 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s
);
3380 h
= size_to_hstate(size
);
3383 * hstate for this size already exists. This is normally
3384 * an error, but is allowed if the existing hstate is the
3385 * default hstate. More specifically, it is only allowed if
3386 * the number of huge pages for the default hstate was not
3387 * previously specified.
3389 if (!parsed_default_hugepagesz
|| h
!= &default_hstate
||
3390 default_hstate
.max_huge_pages
) {
3391 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s
);
3396 * No need to call hugetlb_add_hstate() as hstate already
3397 * exists. But, do set parsed_hstate so that a following
3398 * hugepages= parameter will be applied to this hstate.
3401 parsed_valid_hugepagesz
= true;
3405 hugetlb_add_hstate(ilog2(size
) - PAGE_SHIFT
);
3406 parsed_valid_hugepagesz
= true;
3409 __setup("hugepagesz=", hugepagesz_setup
);
3412 * default_hugepagesz command line input
3413 * Only one instance of default_hugepagesz allowed on command line.
3415 static int __init
default_hugepagesz_setup(char *s
)
3419 parsed_valid_hugepagesz
= false;
3420 if (parsed_default_hugepagesz
) {
3421 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s
);
3425 size
= (unsigned long)memparse(s
, NULL
);
3427 if (!arch_hugetlb_valid_size(size
)) {
3428 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s
);
3432 hugetlb_add_hstate(ilog2(size
) - PAGE_SHIFT
);
3433 parsed_valid_hugepagesz
= true;
3434 parsed_default_hugepagesz
= true;
3435 default_hstate_idx
= hstate_index(size_to_hstate(size
));
3438 * The number of default huge pages (for this size) could have been
3439 * specified as the first hugetlb parameter: hugepages=X. If so,
3440 * then default_hstate_max_huge_pages is set. If the default huge
3441 * page size is gigantic (>= MAX_ORDER), then the pages must be
3442 * allocated here from bootmem allocator.
3444 if (default_hstate_max_huge_pages
) {
3445 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
3446 if (hstate_is_gigantic(&default_hstate
))
3447 hugetlb_hstate_alloc_pages(&default_hstate
);
3448 default_hstate_max_huge_pages
= 0;
3453 __setup("default_hugepagesz=", default_hugepagesz_setup
);
3455 static unsigned int cpuset_mems_nr(unsigned int *array
)
3458 unsigned int nr
= 0;
3460 for_each_node_mask(node
, cpuset_current_mems_allowed
)
3466 #ifdef CONFIG_SYSCTL
3467 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
3468 struct ctl_table
*table
, int write
,
3469 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3471 struct hstate
*h
= &default_hstate
;
3472 unsigned long tmp
= h
->max_huge_pages
;
3475 if (!hugepages_supported())
3479 table
->maxlen
= sizeof(unsigned long);
3480 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3485 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
3486 NUMA_NO_NODE
, tmp
, *length
);
3491 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
3492 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3495 return hugetlb_sysctl_handler_common(false, table
, write
,
3496 buffer
, length
, ppos
);
3500 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3501 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3503 return hugetlb_sysctl_handler_common(true, table
, write
,
3504 buffer
, length
, ppos
);
3506 #endif /* CONFIG_NUMA */
3508 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3509 void __user
*buffer
,
3510 size_t *length
, loff_t
*ppos
)
3512 struct hstate
*h
= &default_hstate
;
3516 if (!hugepages_supported())
3519 tmp
= h
->nr_overcommit_huge_pages
;
3521 if (write
&& hstate_is_gigantic(h
))
3525 table
->maxlen
= sizeof(unsigned long);
3526 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3531 spin_lock(&hugetlb_lock
);
3532 h
->nr_overcommit_huge_pages
= tmp
;
3533 spin_unlock(&hugetlb_lock
);
3539 #endif /* CONFIG_SYSCTL */
3541 void hugetlb_report_meminfo(struct seq_file
*m
)
3544 unsigned long total
= 0;
3546 if (!hugepages_supported())
3549 for_each_hstate(h
) {
3550 unsigned long count
= h
->nr_huge_pages
;
3552 total
+= (PAGE_SIZE
<< huge_page_order(h
)) * count
;
3554 if (h
== &default_hstate
)
3556 "HugePages_Total: %5lu\n"
3557 "HugePages_Free: %5lu\n"
3558 "HugePages_Rsvd: %5lu\n"
3559 "HugePages_Surp: %5lu\n"
3560 "Hugepagesize: %8lu kB\n",
3564 h
->surplus_huge_pages
,
3565 (PAGE_SIZE
<< huge_page_order(h
)) / 1024);
3568 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ 1024);
3571 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3573 struct hstate
*h
= &default_hstate
;
3574 if (!hugepages_supported())
3577 "Node %d HugePages_Total: %5u\n"
3578 "Node %d HugePages_Free: %5u\n"
3579 "Node %d HugePages_Surp: %5u\n",
3580 nid
, h
->nr_huge_pages_node
[nid
],
3581 nid
, h
->free_huge_pages_node
[nid
],
3582 nid
, h
->surplus_huge_pages_node
[nid
]);
3585 void hugetlb_show_meminfo(void)
3590 if (!hugepages_supported())
3593 for_each_node_state(nid
, N_MEMORY
)
3595 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3597 h
->nr_huge_pages_node
[nid
],
3598 h
->free_huge_pages_node
[nid
],
3599 h
->surplus_huge_pages_node
[nid
],
3600 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3603 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3605 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3606 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3609 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3610 unsigned long hugetlb_total_pages(void)
3613 unsigned long nr_total_pages
= 0;
3616 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3617 return nr_total_pages
;
3620 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3624 spin_lock(&hugetlb_lock
);
3626 * When cpuset is configured, it breaks the strict hugetlb page
3627 * reservation as the accounting is done on a global variable. Such
3628 * reservation is completely rubbish in the presence of cpuset because
3629 * the reservation is not checked against page availability for the
3630 * current cpuset. Application can still potentially OOM'ed by kernel
3631 * with lack of free htlb page in cpuset that the task is in.
3632 * Attempt to enforce strict accounting with cpuset is almost
3633 * impossible (or too ugly) because cpuset is too fluid that
3634 * task or memory node can be dynamically moved between cpusets.
3636 * The change of semantics for shared hugetlb mapping with cpuset is
3637 * undesirable. However, in order to preserve some of the semantics,
3638 * we fall back to check against current free page availability as
3639 * a best attempt and hopefully to minimize the impact of changing
3640 * semantics that cpuset has.
3643 if (gather_surplus_pages(h
, delta
) < 0)
3646 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3647 return_unused_surplus_pages(h
, delta
);
3654 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3657 spin_unlock(&hugetlb_lock
);
3661 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3663 struct resv_map
*resv
= vma_resv_map(vma
);
3666 * This new VMA should share its siblings reservation map if present.
3667 * The VMA will only ever have a valid reservation map pointer where
3668 * it is being copied for another still existing VMA. As that VMA
3669 * has a reference to the reservation map it cannot disappear until
3670 * after this open call completes. It is therefore safe to take a
3671 * new reference here without additional locking.
3673 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3674 kref_get(&resv
->refs
);
3677 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3679 struct hstate
*h
= hstate_vma(vma
);
3680 struct resv_map
*resv
= vma_resv_map(vma
);
3681 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3682 unsigned long reserve
, start
, end
;
3685 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3688 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3689 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3691 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3692 hugetlb_cgroup_uncharge_counter(resv
, start
, end
);
3695 * Decrement reserve counts. The global reserve count may be
3696 * adjusted if the subpool has a minimum size.
3698 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3699 hugetlb_acct_memory(h
, -gbl_reserve
);
3702 kref_put(&resv
->refs
, resv_map_release
);
3705 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3707 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3712 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3714 struct hstate
*hstate
= hstate_vma(vma
);
3716 return 1UL << huge_page_shift(hstate
);
3720 * We cannot handle pagefaults against hugetlb pages at all. They cause
3721 * handle_mm_fault() to try to instantiate regular-sized pages in the
3722 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3725 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3732 * When a new function is introduced to vm_operations_struct and added
3733 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3734 * This is because under System V memory model, mappings created via
3735 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3736 * their original vm_ops are overwritten with shm_vm_ops.
3738 const struct vm_operations_struct hugetlb_vm_ops
= {
3739 .fault
= hugetlb_vm_op_fault
,
3740 .open
= hugetlb_vm_op_open
,
3741 .close
= hugetlb_vm_op_close
,
3742 .split
= hugetlb_vm_op_split
,
3743 .pagesize
= hugetlb_vm_op_pagesize
,
3746 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3752 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3753 vma
->vm_page_prot
)));
3755 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3756 vma
->vm_page_prot
));
3758 entry
= pte_mkyoung(entry
);
3759 entry
= pte_mkhuge(entry
);
3760 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3765 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3766 unsigned long address
, pte_t
*ptep
)
3770 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3771 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3772 update_mmu_cache(vma
, address
, ptep
);
3775 bool is_hugetlb_entry_migration(pte_t pte
)
3779 if (huge_pte_none(pte
) || pte_present(pte
))
3781 swp
= pte_to_swp_entry(pte
);
3782 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3788 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3792 if (huge_pte_none(pte
) || pte_present(pte
))
3794 swp
= pte_to_swp_entry(pte
);
3795 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3801 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3802 struct vm_area_struct
*vma
)
3804 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3805 struct page
*ptepage
;
3808 struct hstate
*h
= hstate_vma(vma
);
3809 unsigned long sz
= huge_page_size(h
);
3810 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3811 struct mmu_notifier_range range
;
3814 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3817 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3820 mmu_notifier_invalidate_range_start(&range
);
3823 * For shared mappings i_mmap_rwsem must be held to call
3824 * huge_pte_alloc, otherwise the returned ptep could go
3825 * away if part of a shared pmd and another thread calls
3828 i_mmap_lock_read(mapping
);
3831 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3832 spinlock_t
*src_ptl
, *dst_ptl
;
3833 src_pte
= huge_pte_offset(src
, addr
, sz
);
3836 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3843 * If the pagetables are shared don't copy or take references.
3844 * dst_pte == src_pte is the common case of src/dest sharing.
3846 * However, src could have 'unshared' and dst shares with
3847 * another vma. If dst_pte !none, this implies sharing.
3848 * Check here before taking page table lock, and once again
3849 * after taking the lock below.
3851 dst_entry
= huge_ptep_get(dst_pte
);
3852 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3855 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3856 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3857 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3858 entry
= huge_ptep_get(src_pte
);
3859 dst_entry
= huge_ptep_get(dst_pte
);
3860 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3862 * Skip if src entry none. Also, skip in the
3863 * unlikely case dst entry !none as this implies
3864 * sharing with another vma.
3867 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3868 is_hugetlb_entry_hwpoisoned(entry
))) {
3869 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3871 if (is_write_migration_entry(swp_entry
) && cow
) {
3873 * COW mappings require pages in both
3874 * parent and child to be set to read.
3876 make_migration_entry_read(&swp_entry
);
3877 entry
= swp_entry_to_pte(swp_entry
);
3878 set_huge_swap_pte_at(src
, addr
, src_pte
,
3881 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3885 * No need to notify as we are downgrading page
3886 * table protection not changing it to point
3889 * See Documentation/vm/mmu_notifier.rst
3891 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3893 entry
= huge_ptep_get(src_pte
);
3894 ptepage
= pte_page(entry
);
3896 page_dup_rmap(ptepage
, true);
3897 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3898 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3900 spin_unlock(src_ptl
);
3901 spin_unlock(dst_ptl
);
3905 mmu_notifier_invalidate_range_end(&range
);
3907 i_mmap_unlock_read(mapping
);
3912 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3913 unsigned long start
, unsigned long end
,
3914 struct page
*ref_page
)
3916 struct mm_struct
*mm
= vma
->vm_mm
;
3917 unsigned long address
;
3922 struct hstate
*h
= hstate_vma(vma
);
3923 unsigned long sz
= huge_page_size(h
);
3924 struct mmu_notifier_range range
;
3926 WARN_ON(!is_vm_hugetlb_page(vma
));
3927 BUG_ON(start
& ~huge_page_mask(h
));
3928 BUG_ON(end
& ~huge_page_mask(h
));
3931 * This is a hugetlb vma, all the pte entries should point
3934 tlb_change_page_size(tlb
, sz
);
3935 tlb_start_vma(tlb
, vma
);
3938 * If sharing possible, alert mmu notifiers of worst case.
3940 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3942 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3943 mmu_notifier_invalidate_range_start(&range
);
3945 for (; address
< end
; address
+= sz
) {
3946 ptep
= huge_pte_offset(mm
, address
, sz
);
3950 ptl
= huge_pte_lock(h
, mm
, ptep
);
3951 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3954 * We just unmapped a page of PMDs by clearing a PUD.
3955 * The caller's TLB flush range should cover this area.
3960 pte
= huge_ptep_get(ptep
);
3961 if (huge_pte_none(pte
)) {
3967 * Migrating hugepage or HWPoisoned hugepage is already
3968 * unmapped and its refcount is dropped, so just clear pte here.
3970 if (unlikely(!pte_present(pte
))) {
3971 huge_pte_clear(mm
, address
, ptep
, sz
);
3976 page
= pte_page(pte
);
3978 * If a reference page is supplied, it is because a specific
3979 * page is being unmapped, not a range. Ensure the page we
3980 * are about to unmap is the actual page of interest.
3983 if (page
!= ref_page
) {
3988 * Mark the VMA as having unmapped its page so that
3989 * future faults in this VMA will fail rather than
3990 * looking like data was lost
3992 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3995 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3996 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3997 if (huge_pte_dirty(pte
))
3998 set_page_dirty(page
);
4000 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
4001 page_remove_rmap(page
, true);
4004 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
4006 * Bail out after unmapping reference page if supplied
4011 mmu_notifier_invalidate_range_end(&range
);
4012 tlb_end_vma(tlb
, vma
);
4015 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
4016 struct vm_area_struct
*vma
, unsigned long start
,
4017 unsigned long end
, struct page
*ref_page
)
4019 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
4022 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4023 * test will fail on a vma being torn down, and not grab a page table
4024 * on its way out. We're lucky that the flag has such an appropriate
4025 * name, and can in fact be safely cleared here. We could clear it
4026 * before the __unmap_hugepage_range above, but all that's necessary
4027 * is to clear it before releasing the i_mmap_rwsem. This works
4028 * because in the context this is called, the VMA is about to be
4029 * destroyed and the i_mmap_rwsem is held.
4031 vma
->vm_flags
&= ~VM_MAYSHARE
;
4034 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
4035 unsigned long end
, struct page
*ref_page
)
4037 struct mm_struct
*mm
;
4038 struct mmu_gather tlb
;
4039 unsigned long tlb_start
= start
;
4040 unsigned long tlb_end
= end
;
4043 * If shared PMDs were possibly used within this vma range, adjust
4044 * start/end for worst case tlb flushing.
4045 * Note that we can not be sure if PMDs are shared until we try to
4046 * unmap pages. However, we want to make sure TLB flushing covers
4047 * the largest possible range.
4049 adjust_range_if_pmd_sharing_possible(vma
, &tlb_start
, &tlb_end
);
4053 tlb_gather_mmu(&tlb
, mm
, tlb_start
, tlb_end
);
4054 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
4055 tlb_finish_mmu(&tlb
, tlb_start
, tlb_end
);
4059 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4060 * mappping it owns the reserve page for. The intention is to unmap the page
4061 * from other VMAs and let the children be SIGKILLed if they are faulting the
4064 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4065 struct page
*page
, unsigned long address
)
4067 struct hstate
*h
= hstate_vma(vma
);
4068 struct vm_area_struct
*iter_vma
;
4069 struct address_space
*mapping
;
4073 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4074 * from page cache lookup which is in HPAGE_SIZE units.
4076 address
= address
& huge_page_mask(h
);
4077 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
4079 mapping
= vma
->vm_file
->f_mapping
;
4082 * Take the mapping lock for the duration of the table walk. As
4083 * this mapping should be shared between all the VMAs,
4084 * __unmap_hugepage_range() is called as the lock is already held
4086 i_mmap_lock_write(mapping
);
4087 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
4088 /* Do not unmap the current VMA */
4089 if (iter_vma
== vma
)
4093 * Shared VMAs have their own reserves and do not affect
4094 * MAP_PRIVATE accounting but it is possible that a shared
4095 * VMA is using the same page so check and skip such VMAs.
4097 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
4101 * Unmap the page from other VMAs without their own reserves.
4102 * They get marked to be SIGKILLed if they fault in these
4103 * areas. This is because a future no-page fault on this VMA
4104 * could insert a zeroed page instead of the data existing
4105 * from the time of fork. This would look like data corruption
4107 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
4108 unmap_hugepage_range(iter_vma
, address
,
4109 address
+ huge_page_size(h
), page
);
4111 i_mmap_unlock_write(mapping
);
4115 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4116 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4117 * cannot race with other handlers or page migration.
4118 * Keep the pte_same checks anyway to make transition from the mutex easier.
4120 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4121 unsigned long address
, pte_t
*ptep
,
4122 struct page
*pagecache_page
, spinlock_t
*ptl
)
4125 struct hstate
*h
= hstate_vma(vma
);
4126 struct page
*old_page
, *new_page
;
4127 int outside_reserve
= 0;
4129 unsigned long haddr
= address
& huge_page_mask(h
);
4130 struct mmu_notifier_range range
;
4132 pte
= huge_ptep_get(ptep
);
4133 old_page
= pte_page(pte
);
4136 /* If no-one else is actually using this page, avoid the copy
4137 * and just make the page writable */
4138 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
4139 page_move_anon_rmap(old_page
, vma
);
4140 set_huge_ptep_writable(vma
, haddr
, ptep
);
4145 * If the process that created a MAP_PRIVATE mapping is about to
4146 * perform a COW due to a shared page count, attempt to satisfy
4147 * the allocation without using the existing reserves. The pagecache
4148 * page is used to determine if the reserve at this address was
4149 * consumed or not. If reserves were used, a partial faulted mapping
4150 * at the time of fork() could consume its reserves on COW instead
4151 * of the full address range.
4153 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
4154 old_page
!= pagecache_page
)
4155 outside_reserve
= 1;
4160 * Drop page table lock as buddy allocator may be called. It will
4161 * be acquired again before returning to the caller, as expected.
4164 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
4166 if (IS_ERR(new_page
)) {
4168 * If a process owning a MAP_PRIVATE mapping fails to COW,
4169 * it is due to references held by a child and an insufficient
4170 * huge page pool. To guarantee the original mappers
4171 * reliability, unmap the page from child processes. The child
4172 * may get SIGKILLed if it later faults.
4174 if (outside_reserve
) {
4176 BUG_ON(huge_pte_none(pte
));
4177 unmap_ref_private(mm
, vma
, old_page
, haddr
);
4178 BUG_ON(huge_pte_none(pte
));
4180 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4182 pte_same(huge_ptep_get(ptep
), pte
)))
4183 goto retry_avoidcopy
;
4185 * race occurs while re-acquiring page table
4186 * lock, and our job is done.
4191 ret
= vmf_error(PTR_ERR(new_page
));
4192 goto out_release_old
;
4196 * When the original hugepage is shared one, it does not have
4197 * anon_vma prepared.
4199 if (unlikely(anon_vma_prepare(vma
))) {
4201 goto out_release_all
;
4204 copy_user_huge_page(new_page
, old_page
, address
, vma
,
4205 pages_per_huge_page(h
));
4206 __SetPageUptodate(new_page
);
4208 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
4209 haddr
+ huge_page_size(h
));
4210 mmu_notifier_invalidate_range_start(&range
);
4213 * Retake the page table lock to check for racing updates
4214 * before the page tables are altered
4217 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4218 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
4219 ClearPagePrivate(new_page
);
4222 huge_ptep_clear_flush(vma
, haddr
, ptep
);
4223 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
4224 set_huge_pte_at(mm
, haddr
, ptep
,
4225 make_huge_pte(vma
, new_page
, 1));
4226 page_remove_rmap(old_page
, true);
4227 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
4228 set_page_huge_active(new_page
);
4229 /* Make the old page be freed below */
4230 new_page
= old_page
;
4233 mmu_notifier_invalidate_range_end(&range
);
4235 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
4240 spin_lock(ptl
); /* Caller expects lock to be held */
4244 /* Return the pagecache page at a given address within a VMA */
4245 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
4246 struct vm_area_struct
*vma
, unsigned long address
)
4248 struct address_space
*mapping
;
4251 mapping
= vma
->vm_file
->f_mapping
;
4252 idx
= vma_hugecache_offset(h
, vma
, address
);
4254 return find_lock_page(mapping
, idx
);
4258 * Return whether there is a pagecache page to back given address within VMA.
4259 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4261 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
4262 struct vm_area_struct
*vma
, unsigned long address
)
4264 struct address_space
*mapping
;
4268 mapping
= vma
->vm_file
->f_mapping
;
4269 idx
= vma_hugecache_offset(h
, vma
, address
);
4271 page
= find_get_page(mapping
, idx
);
4274 return page
!= NULL
;
4277 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
4280 struct inode
*inode
= mapping
->host
;
4281 struct hstate
*h
= hstate_inode(inode
);
4282 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
4286 ClearPagePrivate(page
);
4289 * set page dirty so that it will not be removed from cache/file
4290 * by non-hugetlbfs specific code paths.
4292 set_page_dirty(page
);
4294 spin_lock(&inode
->i_lock
);
4295 inode
->i_blocks
+= blocks_per_huge_page(h
);
4296 spin_unlock(&inode
->i_lock
);
4300 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
4301 struct vm_area_struct
*vma
,
4302 struct address_space
*mapping
, pgoff_t idx
,
4303 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
4305 struct hstate
*h
= hstate_vma(vma
);
4306 vm_fault_t ret
= VM_FAULT_SIGBUS
;
4312 unsigned long haddr
= address
& huge_page_mask(h
);
4313 bool new_page
= false;
4316 * Currently, we are forced to kill the process in the event the
4317 * original mapper has unmapped pages from the child due to a failed
4318 * COW. Warn that such a situation has occurred as it may not be obvious
4320 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
4321 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4327 * We can not race with truncation due to holding i_mmap_rwsem.
4328 * i_size is modified when holding i_mmap_rwsem, so check here
4329 * once for faults beyond end of file.
4331 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4336 page
= find_lock_page(mapping
, idx
);
4339 * Check for page in userfault range
4341 if (userfaultfd_missing(vma
)) {
4343 struct vm_fault vmf
= {
4348 * Hard to debug if it ends up being
4349 * used by a callee that assumes
4350 * something about the other
4351 * uninitialized fields... same as in
4357 * hugetlb_fault_mutex and i_mmap_rwsem must be
4358 * dropped before handling userfault. Reacquire
4359 * after handling fault to make calling code simpler.
4361 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4362 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4363 i_mmap_unlock_read(mapping
);
4364 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
4365 i_mmap_lock_read(mapping
);
4366 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4370 page
= alloc_huge_page(vma
, haddr
, 0);
4373 * Returning error will result in faulting task being
4374 * sent SIGBUS. The hugetlb fault mutex prevents two
4375 * tasks from racing to fault in the same page which
4376 * could result in false unable to allocate errors.
4377 * Page migration does not take the fault mutex, but
4378 * does a clear then write of pte's under page table
4379 * lock. Page fault code could race with migration,
4380 * notice the clear pte and try to allocate a page
4381 * here. Before returning error, get ptl and make
4382 * sure there really is no pte entry.
4384 ptl
= huge_pte_lock(h
, mm
, ptep
);
4385 if (!huge_pte_none(huge_ptep_get(ptep
))) {
4391 ret
= vmf_error(PTR_ERR(page
));
4394 clear_huge_page(page
, address
, pages_per_huge_page(h
));
4395 __SetPageUptodate(page
);
4398 if (vma
->vm_flags
& VM_MAYSHARE
) {
4399 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
4408 if (unlikely(anon_vma_prepare(vma
))) {
4410 goto backout_unlocked
;
4416 * If memory error occurs between mmap() and fault, some process
4417 * don't have hwpoisoned swap entry for errored virtual address.
4418 * So we need to block hugepage fault by PG_hwpoison bit check.
4420 if (unlikely(PageHWPoison(page
))) {
4421 ret
= VM_FAULT_HWPOISON
|
4422 VM_FAULT_SET_HINDEX(hstate_index(h
));
4423 goto backout_unlocked
;
4428 * If we are going to COW a private mapping later, we examine the
4429 * pending reservations for this page now. This will ensure that
4430 * any allocations necessary to record that reservation occur outside
4433 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4434 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4436 goto backout_unlocked
;
4438 /* Just decrements count, does not deallocate */
4439 vma_end_reservation(h
, vma
, haddr
);
4442 ptl
= huge_pte_lock(h
, mm
, ptep
);
4444 if (!huge_pte_none(huge_ptep_get(ptep
)))
4448 ClearPagePrivate(page
);
4449 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
4451 page_dup_rmap(page
, true);
4452 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
4453 && (vma
->vm_flags
& VM_SHARED
)));
4454 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
4456 hugetlb_count_add(pages_per_huge_page(h
), mm
);
4457 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4458 /* Optimization, do the COW without a second fault */
4459 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
4465 * Only make newly allocated pages active. Existing pages found
4466 * in the pagecache could be !page_huge_active() if they have been
4467 * isolated for migration.
4470 set_page_huge_active(page
);
4480 restore_reserve_on_error(h
, vma
, haddr
, page
);
4486 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4488 unsigned long key
[2];
4491 key
[0] = (unsigned long) mapping
;
4494 hash
= jhash2((u32
*)&key
, sizeof(key
)/(sizeof(u32
)), 0);
4496 return hash
& (num_fault_mutexes
- 1);
4500 * For uniprocesor systems we always use a single mutex, so just
4501 * return 0 and avoid the hashing overhead.
4503 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4509 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4510 unsigned long address
, unsigned int flags
)
4517 struct page
*page
= NULL
;
4518 struct page
*pagecache_page
= NULL
;
4519 struct hstate
*h
= hstate_vma(vma
);
4520 struct address_space
*mapping
;
4521 int need_wait_lock
= 0;
4522 unsigned long haddr
= address
& huge_page_mask(h
);
4524 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4527 * Since we hold no locks, ptep could be stale. That is
4528 * OK as we are only making decisions based on content and
4529 * not actually modifying content here.
4531 entry
= huge_ptep_get(ptep
);
4532 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4533 migration_entry_wait_huge(vma
, mm
, ptep
);
4535 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4536 return VM_FAULT_HWPOISON_LARGE
|
4537 VM_FAULT_SET_HINDEX(hstate_index(h
));
4539 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4541 return VM_FAULT_OOM
;
4545 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4546 * until finished with ptep. This serves two purposes:
4547 * 1) It prevents huge_pmd_unshare from being called elsewhere
4548 * and making the ptep no longer valid.
4549 * 2) It synchronizes us with i_size modifications during truncation.
4551 * ptep could have already be assigned via huge_pte_offset. That
4552 * is OK, as huge_pte_alloc will return the same value unless
4553 * something has changed.
4555 mapping
= vma
->vm_file
->f_mapping
;
4556 i_mmap_lock_read(mapping
);
4557 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4559 i_mmap_unlock_read(mapping
);
4560 return VM_FAULT_OOM
;
4564 * Serialize hugepage allocation and instantiation, so that we don't
4565 * get spurious allocation failures if two CPUs race to instantiate
4566 * the same page in the page cache.
4568 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4569 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4570 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4572 entry
= huge_ptep_get(ptep
);
4573 if (huge_pte_none(entry
)) {
4574 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4581 * entry could be a migration/hwpoison entry at this point, so this
4582 * check prevents the kernel from going below assuming that we have
4583 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4584 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4587 if (!pte_present(entry
))
4591 * If we are going to COW the mapping later, we examine the pending
4592 * reservations for this page now. This will ensure that any
4593 * allocations necessary to record that reservation occur outside the
4594 * spinlock. For private mappings, we also lookup the pagecache
4595 * page now as it is used to determine if a reservation has been
4598 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4599 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4603 /* Just decrements count, does not deallocate */
4604 vma_end_reservation(h
, vma
, haddr
);
4606 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4607 pagecache_page
= hugetlbfs_pagecache_page(h
,
4611 ptl
= huge_pte_lock(h
, mm
, ptep
);
4613 /* Check for a racing update before calling hugetlb_cow */
4614 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4618 * hugetlb_cow() requires page locks of pte_page(entry) and
4619 * pagecache_page, so here we need take the former one
4620 * when page != pagecache_page or !pagecache_page.
4622 page
= pte_page(entry
);
4623 if (page
!= pagecache_page
)
4624 if (!trylock_page(page
)) {
4631 if (flags
& FAULT_FLAG_WRITE
) {
4632 if (!huge_pte_write(entry
)) {
4633 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4634 pagecache_page
, ptl
);
4637 entry
= huge_pte_mkdirty(entry
);
4639 entry
= pte_mkyoung(entry
);
4640 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4641 flags
& FAULT_FLAG_WRITE
))
4642 update_mmu_cache(vma
, haddr
, ptep
);
4644 if (page
!= pagecache_page
)
4650 if (pagecache_page
) {
4651 unlock_page(pagecache_page
);
4652 put_page(pagecache_page
);
4655 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4656 i_mmap_unlock_read(mapping
);
4658 * Generally it's safe to hold refcount during waiting page lock. But
4659 * here we just wait to defer the next page fault to avoid busy loop and
4660 * the page is not used after unlocked before returning from the current
4661 * page fault. So we are safe from accessing freed page, even if we wait
4662 * here without taking refcount.
4665 wait_on_page_locked(page
);
4670 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4671 * modifications for huge pages.
4673 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4675 struct vm_area_struct
*dst_vma
,
4676 unsigned long dst_addr
,
4677 unsigned long src_addr
,
4678 struct page
**pagep
)
4680 struct address_space
*mapping
;
4683 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4684 struct hstate
*h
= hstate_vma(dst_vma
);
4692 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4696 ret
= copy_huge_page_from_user(page
,
4697 (const void __user
*) src_addr
,
4698 pages_per_huge_page(h
), false);
4700 /* fallback to copy_from_user outside mmap_sem */
4701 if (unlikely(ret
)) {
4704 /* don't free the page */
4713 * The memory barrier inside __SetPageUptodate makes sure that
4714 * preceding stores to the page contents become visible before
4715 * the set_pte_at() write.
4717 __SetPageUptodate(page
);
4719 mapping
= dst_vma
->vm_file
->f_mapping
;
4720 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4723 * If shared, add to page cache
4726 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4729 goto out_release_nounlock
;
4732 * Serialization between remove_inode_hugepages() and
4733 * huge_add_to_page_cache() below happens through the
4734 * hugetlb_fault_mutex_table that here must be hold by
4737 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4739 goto out_release_nounlock
;
4742 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4746 * Recheck the i_size after holding PT lock to make sure not
4747 * to leave any page mapped (as page_mapped()) beyond the end
4748 * of the i_size (remove_inode_hugepages() is strict about
4749 * enforcing that). If we bail out here, we'll also leave a
4750 * page in the radix tree in the vm_shared case beyond the end
4751 * of the i_size, but remove_inode_hugepages() will take care
4752 * of it as soon as we drop the hugetlb_fault_mutex_table.
4754 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4757 goto out_release_unlock
;
4760 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4761 goto out_release_unlock
;
4764 page_dup_rmap(page
, true);
4766 ClearPagePrivate(page
);
4767 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4770 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4771 if (dst_vma
->vm_flags
& VM_WRITE
)
4772 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4773 _dst_pte
= pte_mkyoung(_dst_pte
);
4775 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4777 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4778 dst_vma
->vm_flags
& VM_WRITE
);
4779 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4781 /* No need to invalidate - it was non-present before */
4782 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4785 set_page_huge_active(page
);
4795 out_release_nounlock
:
4800 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4801 struct page
**pages
, struct vm_area_struct
**vmas
,
4802 unsigned long *position
, unsigned long *nr_pages
,
4803 long i
, unsigned int flags
, int *locked
)
4805 unsigned long pfn_offset
;
4806 unsigned long vaddr
= *position
;
4807 unsigned long remainder
= *nr_pages
;
4808 struct hstate
*h
= hstate_vma(vma
);
4811 while (vaddr
< vma
->vm_end
&& remainder
) {
4813 spinlock_t
*ptl
= NULL
;
4818 * If we have a pending SIGKILL, don't keep faulting pages and
4819 * potentially allocating memory.
4821 if (fatal_signal_pending(current
)) {
4827 * Some archs (sparc64, sh*) have multiple pte_ts to
4828 * each hugepage. We have to make sure we get the
4829 * first, for the page indexing below to work.
4831 * Note that page table lock is not held when pte is null.
4833 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4836 ptl
= huge_pte_lock(h
, mm
, pte
);
4837 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4840 * When coredumping, it suits get_dump_page if we just return
4841 * an error where there's an empty slot with no huge pagecache
4842 * to back it. This way, we avoid allocating a hugepage, and
4843 * the sparse dumpfile avoids allocating disk blocks, but its
4844 * huge holes still show up with zeroes where they need to be.
4846 if (absent
&& (flags
& FOLL_DUMP
) &&
4847 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4855 * We need call hugetlb_fault for both hugepages under migration
4856 * (in which case hugetlb_fault waits for the migration,) and
4857 * hwpoisoned hugepages (in which case we need to prevent the
4858 * caller from accessing to them.) In order to do this, we use
4859 * here is_swap_pte instead of is_hugetlb_entry_migration and
4860 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4861 * both cases, and because we can't follow correct pages
4862 * directly from any kind of swap entries.
4864 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4865 ((flags
& FOLL_WRITE
) &&
4866 !huge_pte_write(huge_ptep_get(pte
)))) {
4868 unsigned int fault_flags
= 0;
4872 if (flags
& FOLL_WRITE
)
4873 fault_flags
|= FAULT_FLAG_WRITE
;
4875 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4876 FAULT_FLAG_KILLABLE
;
4877 if (flags
& FOLL_NOWAIT
)
4878 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4879 FAULT_FLAG_RETRY_NOWAIT
;
4880 if (flags
& FOLL_TRIED
) {
4882 * Note: FAULT_FLAG_ALLOW_RETRY and
4883 * FAULT_FLAG_TRIED can co-exist
4885 fault_flags
|= FAULT_FLAG_TRIED
;
4887 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4888 if (ret
& VM_FAULT_ERROR
) {
4889 err
= vm_fault_to_errno(ret
, flags
);
4893 if (ret
& VM_FAULT_RETRY
) {
4895 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4899 * VM_FAULT_RETRY must not return an
4900 * error, it will return zero
4903 * No need to update "position" as the
4904 * caller will not check it after
4905 * *nr_pages is set to 0.
4912 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4913 page
= pte_page(huge_ptep_get(pte
));
4916 * If subpage information not requested, update counters
4917 * and skip the same_page loop below.
4919 if (!pages
&& !vmas
&& !pfn_offset
&&
4920 (vaddr
+ huge_page_size(h
) < vma
->vm_end
) &&
4921 (remainder
>= pages_per_huge_page(h
))) {
4922 vaddr
+= huge_page_size(h
);
4923 remainder
-= pages_per_huge_page(h
);
4924 i
+= pages_per_huge_page(h
);
4931 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4933 * try_grab_page() should always succeed here, because:
4934 * a) we hold the ptl lock, and b) we've just checked
4935 * that the huge page is present in the page tables. If
4936 * the huge page is present, then the tail pages must
4937 * also be present. The ptl prevents the head page and
4938 * tail pages from being rearranged in any way. So this
4939 * page must be available at this point, unless the page
4940 * refcount overflowed:
4942 if (WARN_ON_ONCE(!try_grab_page(pages
[i
], flags
))) {
4957 if (vaddr
< vma
->vm_end
&& remainder
&&
4958 pfn_offset
< pages_per_huge_page(h
)) {
4960 * We use pfn_offset to avoid touching the pageframes
4961 * of this compound page.
4967 *nr_pages
= remainder
;
4969 * setting position is actually required only if remainder is
4970 * not zero but it's faster not to add a "if (remainder)"
4978 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4980 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4983 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4986 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4987 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4989 struct mm_struct
*mm
= vma
->vm_mm
;
4990 unsigned long start
= address
;
4993 struct hstate
*h
= hstate_vma(vma
);
4994 unsigned long pages
= 0;
4995 bool shared_pmd
= false;
4996 struct mmu_notifier_range range
;
4999 * In the case of shared PMDs, the area to flush could be beyond
5000 * start/end. Set range.start/range.end to cover the maximum possible
5001 * range if PMD sharing is possible.
5003 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
5004 0, vma
, mm
, start
, end
);
5005 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
5007 BUG_ON(address
>= end
);
5008 flush_cache_range(vma
, range
.start
, range
.end
);
5010 mmu_notifier_invalidate_range_start(&range
);
5011 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
5012 for (; address
< end
; address
+= huge_page_size(h
)) {
5014 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
5017 ptl
= huge_pte_lock(h
, mm
, ptep
);
5018 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
5024 pte
= huge_ptep_get(ptep
);
5025 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
5029 if (unlikely(is_hugetlb_entry_migration(pte
))) {
5030 swp_entry_t entry
= pte_to_swp_entry(pte
);
5032 if (is_write_migration_entry(entry
)) {
5035 make_migration_entry_read(&entry
);
5036 newpte
= swp_entry_to_pte(entry
);
5037 set_huge_swap_pte_at(mm
, address
, ptep
,
5038 newpte
, huge_page_size(h
));
5044 if (!huge_pte_none(pte
)) {
5047 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
5048 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
5049 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
5050 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
5056 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5057 * may have cleared our pud entry and done put_page on the page table:
5058 * once we release i_mmap_rwsem, another task can do the final put_page
5059 * and that page table be reused and filled with junk. If we actually
5060 * did unshare a page of pmds, flush the range corresponding to the pud.
5063 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
5065 flush_hugetlb_tlb_range(vma
, start
, end
);
5067 * No need to call mmu_notifier_invalidate_range() we are downgrading
5068 * page table protection not changing it to point to a new page.
5070 * See Documentation/vm/mmu_notifier.rst
5072 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
5073 mmu_notifier_invalidate_range_end(&range
);
5075 return pages
<< h
->order
;
5078 int hugetlb_reserve_pages(struct inode
*inode
,
5080 struct vm_area_struct
*vma
,
5081 vm_flags_t vm_flags
)
5083 long ret
, chg
, add
= -1;
5084 struct hstate
*h
= hstate_inode(inode
);
5085 struct hugepage_subpool
*spool
= subpool_inode(inode
);
5086 struct resv_map
*resv_map
;
5087 struct hugetlb_cgroup
*h_cg
= NULL
;
5088 long gbl_reserve
, regions_needed
= 0;
5090 /* This should never happen */
5092 VM_WARN(1, "%s called with a negative range\n", __func__
);
5097 * Only apply hugepage reservation if asked. At fault time, an
5098 * attempt will be made for VM_NORESERVE to allocate a page
5099 * without using reserves
5101 if (vm_flags
& VM_NORESERVE
)
5105 * Shared mappings base their reservation on the number of pages that
5106 * are already allocated on behalf of the file. Private mappings need
5107 * to reserve the full area even if read-only as mprotect() may be
5108 * called to make the mapping read-write. Assume !vma is a shm mapping
5110 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
5112 * resv_map can not be NULL as hugetlb_reserve_pages is only
5113 * called for inodes for which resv_maps were created (see
5114 * hugetlbfs_get_inode).
5116 resv_map
= inode_resv_map(inode
);
5118 chg
= region_chg(resv_map
, from
, to
, ®ions_needed
);
5121 /* Private mapping. */
5122 resv_map
= resv_map_alloc();
5128 set_vma_resv_map(vma
, resv_map
);
5129 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
5137 ret
= hugetlb_cgroup_charge_cgroup_rsvd(
5138 hstate_index(h
), chg
* pages_per_huge_page(h
), &h_cg
);
5145 if (vma
&& !(vma
->vm_flags
& VM_MAYSHARE
) && h_cg
) {
5146 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5149 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, h_cg
, h
);
5153 * There must be enough pages in the subpool for the mapping. If
5154 * the subpool has a minimum size, there may be some global
5155 * reservations already in place (gbl_reserve).
5157 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
5158 if (gbl_reserve
< 0) {
5160 goto out_uncharge_cgroup
;
5164 * Check enough hugepages are available for the reservation.
5165 * Hand the pages back to the subpool if there are not
5167 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
5173 * Account for the reservations made. Shared mappings record regions
5174 * that have reservations as they are shared by multiple VMAs.
5175 * When the last VMA disappears, the region map says how much
5176 * the reservation was and the page cache tells how much of
5177 * the reservation was consumed. Private mappings are per-VMA and
5178 * only the consumed reservations are tracked. When the VMA
5179 * disappears, the original reservation is the VMA size and the
5180 * consumed reservations are stored in the map. Hence, nothing
5181 * else has to be done for private mappings here
5183 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
5184 add
= region_add(resv_map
, from
, to
, regions_needed
, h
, h_cg
);
5186 if (unlikely(add
< 0)) {
5187 hugetlb_acct_memory(h
, -gbl_reserve
);
5189 } else if (unlikely(chg
> add
)) {
5191 * pages in this range were added to the reserve
5192 * map between region_chg and region_add. This
5193 * indicates a race with alloc_huge_page. Adjust
5194 * the subpool and reserve counts modified above
5195 * based on the difference.
5199 hugetlb_cgroup_uncharge_cgroup_rsvd(
5201 (chg
- add
) * pages_per_huge_page(h
), h_cg
);
5203 rsv_adjust
= hugepage_subpool_put_pages(spool
,
5205 hugetlb_acct_memory(h
, -rsv_adjust
);
5210 /* put back original number of pages, chg */
5211 (void)hugepage_subpool_put_pages(spool
, chg
);
5212 out_uncharge_cgroup
:
5213 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h
),
5214 chg
* pages_per_huge_page(h
), h_cg
);
5216 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
5217 /* Only call region_abort if the region_chg succeeded but the
5218 * region_add failed or didn't run.
5220 if (chg
>= 0 && add
< 0)
5221 region_abort(resv_map
, from
, to
, regions_needed
);
5222 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
5223 kref_put(&resv_map
->refs
, resv_map_release
);
5227 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
5230 struct hstate
*h
= hstate_inode(inode
);
5231 struct resv_map
*resv_map
= inode_resv_map(inode
);
5233 struct hugepage_subpool
*spool
= subpool_inode(inode
);
5237 * Since this routine can be called in the evict inode path for all
5238 * hugetlbfs inodes, resv_map could be NULL.
5241 chg
= region_del(resv_map
, start
, end
);
5243 * region_del() can fail in the rare case where a region
5244 * must be split and another region descriptor can not be
5245 * allocated. If end == LONG_MAX, it will not fail.
5251 spin_lock(&inode
->i_lock
);
5252 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
5253 spin_unlock(&inode
->i_lock
);
5256 * If the subpool has a minimum size, the number of global
5257 * reservations to be released may be adjusted.
5259 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
5260 hugetlb_acct_memory(h
, -gbl_reserve
);
5265 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5266 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
5267 struct vm_area_struct
*vma
,
5268 unsigned long addr
, pgoff_t idx
)
5270 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
5272 unsigned long sbase
= saddr
& PUD_MASK
;
5273 unsigned long s_end
= sbase
+ PUD_SIZE
;
5275 /* Allow segments to share if only one is marked locked */
5276 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5277 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5280 * match the virtual addresses, permission and the alignment of the
5283 if (pmd_index(addr
) != pmd_index(saddr
) ||
5284 vm_flags
!= svm_flags
||
5285 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
5291 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
5293 unsigned long base
= addr
& PUD_MASK
;
5294 unsigned long end
= base
+ PUD_SIZE
;
5297 * check on proper vm_flags and page table alignment
5299 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
5305 * Determine if start,end range within vma could be mapped by shared pmd.
5306 * If yes, adjust start and end to cover range associated with possible
5307 * shared pmd mappings.
5309 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5310 unsigned long *start
, unsigned long *end
)
5312 unsigned long check_addr
;
5314 if (!(vma
->vm_flags
& VM_MAYSHARE
))
5317 for (check_addr
= *start
; check_addr
< *end
; check_addr
+= PUD_SIZE
) {
5318 unsigned long a_start
= check_addr
& PUD_MASK
;
5319 unsigned long a_end
= a_start
+ PUD_SIZE
;
5322 * If sharing is possible, adjust start/end if necessary.
5324 if (range_in_vma(vma
, a_start
, a_end
)) {
5325 if (a_start
< *start
)
5334 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5335 * and returns the corresponding pte. While this is not necessary for the
5336 * !shared pmd case because we can allocate the pmd later as well, it makes the
5337 * code much cleaner.
5339 * This routine must be called with i_mmap_rwsem held in at least read mode.
5340 * For hugetlbfs, this prevents removal of any page table entries associated
5341 * with the address space. This is important as we are setting up sharing
5342 * based on existing page table entries (mappings).
5344 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5346 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
5347 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
5348 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
5350 struct vm_area_struct
*svma
;
5351 unsigned long saddr
;
5356 if (!vma_shareable(vma
, addr
))
5357 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5359 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
5363 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
5365 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
5366 vma_mmu_pagesize(svma
));
5368 get_page(virt_to_page(spte
));
5377 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
5378 if (pud_none(*pud
)) {
5379 pud_populate(mm
, pud
,
5380 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
5383 put_page(virt_to_page(spte
));
5387 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5392 * unmap huge page backed by shared pte.
5394 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5395 * indicated by page_count > 1, unmap is achieved by clearing pud and
5396 * decrementing the ref count. If count == 1, the pte page is not shared.
5398 * Called with page table lock held and i_mmap_rwsem held in write mode.
5400 * returns: 1 successfully unmapped a shared pte page
5401 * 0 the underlying pte page is not shared, or it is the last user
5403 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5405 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
5406 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
5407 pud_t
*pud
= pud_offset(p4d
, *addr
);
5409 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
5410 if (page_count(virt_to_page(ptep
)) == 1)
5414 put_page(virt_to_page(ptep
));
5416 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
5419 #define want_pmd_share() (1)
5420 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5421 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5426 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5431 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5432 unsigned long *start
, unsigned long *end
)
5435 #define want_pmd_share() (0)
5436 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5438 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5439 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
5440 unsigned long addr
, unsigned long sz
)
5447 pgd
= pgd_offset(mm
, addr
);
5448 p4d
= p4d_alloc(mm
, pgd
, addr
);
5451 pud
= pud_alloc(mm
, p4d
, addr
);
5453 if (sz
== PUD_SIZE
) {
5456 BUG_ON(sz
!= PMD_SIZE
);
5457 if (want_pmd_share() && pud_none(*pud
))
5458 pte
= huge_pmd_share(mm
, addr
, pud
);
5460 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5463 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
5469 * huge_pte_offset() - Walk the page table to resolve the hugepage
5470 * entry at address @addr
5472 * Return: Pointer to page table entry (PUD or PMD) for
5473 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5474 * size @sz doesn't match the hugepage size at this level of the page
5477 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
5478 unsigned long addr
, unsigned long sz
)
5485 pgd
= pgd_offset(mm
, addr
);
5486 if (!pgd_present(*pgd
))
5488 p4d
= p4d_offset(pgd
, addr
);
5489 if (!p4d_present(*p4d
))
5492 pud
= pud_offset(p4d
, addr
);
5494 /* must be pud huge, non-present or none */
5495 return (pte_t
*)pud
;
5496 if (!pud_present(*pud
))
5498 /* must have a valid entry and size to go further */
5500 pmd
= pmd_offset(pud
, addr
);
5501 /* must be pmd huge, non-present or none */
5502 return (pte_t
*)pmd
;
5505 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5508 * These functions are overwritable if your architecture needs its own
5511 struct page
* __weak
5512 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
5515 return ERR_PTR(-EINVAL
);
5518 struct page
* __weak
5519 follow_huge_pd(struct vm_area_struct
*vma
,
5520 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
5522 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5526 struct page
* __weak
5527 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
5528 pmd_t
*pmd
, int flags
)
5530 struct page
*page
= NULL
;
5534 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5535 if (WARN_ON_ONCE((flags
& (FOLL_PIN
| FOLL_GET
)) ==
5536 (FOLL_PIN
| FOLL_GET
)))
5540 ptl
= pmd_lockptr(mm
, pmd
);
5543 * make sure that the address range covered by this pmd is not
5544 * unmapped from other threads.
5546 if (!pmd_huge(*pmd
))
5548 pte
= huge_ptep_get((pte_t
*)pmd
);
5549 if (pte_present(pte
)) {
5550 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
5552 * try_grab_page() should always succeed here, because: a) we
5553 * hold the pmd (ptl) lock, and b) we've just checked that the
5554 * huge pmd (head) page is present in the page tables. The ptl
5555 * prevents the head page and tail pages from being rearranged
5556 * in any way. So this page must be available at this point,
5557 * unless the page refcount overflowed:
5559 if (WARN_ON_ONCE(!try_grab_page(page
, flags
))) {
5564 if (is_hugetlb_entry_migration(pte
)) {
5566 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5570 * hwpoisoned entry is treated as no_page_table in
5571 * follow_page_mask().
5579 struct page
* __weak
5580 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5581 pud_t
*pud
, int flags
)
5583 if (flags
& (FOLL_GET
| FOLL_PIN
))
5586 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5589 struct page
* __weak
5590 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5592 if (flags
& (FOLL_GET
| FOLL_PIN
))
5595 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5598 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5602 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5603 spin_lock(&hugetlb_lock
);
5604 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
5608 clear_page_huge_active(page
);
5609 list_move_tail(&page
->lru
, list
);
5611 spin_unlock(&hugetlb_lock
);
5615 void putback_active_hugepage(struct page
*page
)
5617 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5618 spin_lock(&hugetlb_lock
);
5619 set_page_huge_active(page
);
5620 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5621 spin_unlock(&hugetlb_lock
);
5625 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5627 struct hstate
*h
= page_hstate(oldpage
);
5629 hugetlb_cgroup_migrate(oldpage
, newpage
);
5630 set_page_owner_migrate_reason(newpage
, reason
);
5633 * transfer temporary state of the new huge page. This is
5634 * reverse to other transitions because the newpage is going to
5635 * be final while the old one will be freed so it takes over
5636 * the temporary status.
5638 * Also note that we have to transfer the per-node surplus state
5639 * here as well otherwise the global surplus count will not match
5642 if (PageHugeTemporary(newpage
)) {
5643 int old_nid
= page_to_nid(oldpage
);
5644 int new_nid
= page_to_nid(newpage
);
5646 SetPageHugeTemporary(oldpage
);
5647 ClearPageHugeTemporary(newpage
);
5649 spin_lock(&hugetlb_lock
);
5650 if (h
->surplus_huge_pages_node
[old_nid
]) {
5651 h
->surplus_huge_pages_node
[old_nid
]--;
5652 h
->surplus_huge_pages_node
[new_nid
]++;
5654 spin_unlock(&hugetlb_lock
);
5659 static unsigned long hugetlb_cma_size __initdata
;
5660 static bool cma_reserve_called __initdata
;
5662 static int __init
cmdline_parse_hugetlb_cma(char *p
)
5664 hugetlb_cma_size
= memparse(p
, &p
);
5668 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma
);
5670 void __init
hugetlb_cma_reserve(int order
)
5672 unsigned long size
, reserved
, per_node
;
5675 cma_reserve_called
= true;
5677 if (!hugetlb_cma_size
)
5680 if (hugetlb_cma_size
< (PAGE_SIZE
<< order
)) {
5681 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5682 (PAGE_SIZE
<< order
) / SZ_1M
);
5687 * If 3 GB area is requested on a machine with 4 numa nodes,
5688 * let's allocate 1 GB on first three nodes and ignore the last one.
5690 per_node
= DIV_ROUND_UP(hugetlb_cma_size
, nr_online_nodes
);
5691 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5692 hugetlb_cma_size
/ SZ_1M
, per_node
/ SZ_1M
);
5695 for_each_node_state(nid
, N_ONLINE
) {
5698 size
= min(per_node
, hugetlb_cma_size
- reserved
);
5699 size
= round_up(size
, PAGE_SIZE
<< order
);
5701 res
= cma_declare_contiguous_nid(0, size
, 0, PAGE_SIZE
<< order
,
5702 0, false, "hugetlb",
5703 &hugetlb_cma
[nid
], nid
);
5705 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
5711 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
5714 if (reserved
>= hugetlb_cma_size
)
5719 void __init
hugetlb_cma_check(void)
5721 if (!hugetlb_cma_size
|| cma_reserve_called
)
5724 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
5727 #endif /* CONFIG_CMA */