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/sched/mm.h>
23 #include <linux/mmdebug.h>
24 #include <linux/sched/signal.h>
25 #include <linux/rmap.h>
26 #include <linux/string_helpers.h>
27 #include <linux/swap.h>
28 #include <linux/swapops.h>
29 #include <linux/jhash.h>
30 #include <linux/numa.h>
31 #include <linux/llist.h>
32 #include <linux/cma.h>
35 #include <asm/pgalloc.h>
39 #include <linux/hugetlb.h>
40 #include <linux/hugetlb_cgroup.h>
41 #include <linux/node.h>
42 #include <linux/userfaultfd_k.h>
43 #include <linux/page_owner.h>
46 int hugetlb_max_hstate __read_mostly
;
47 unsigned int default_hstate_idx
;
48 struct hstate hstates
[HUGE_MAX_HSTATE
];
51 static struct cma
*hugetlb_cma
[MAX_NUMNODES
];
53 static unsigned long hugetlb_cma_size __initdata
;
56 * Minimum page order among possible hugepage sizes, set to a proper value
59 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
61 __initdata
LIST_HEAD(huge_boot_pages
);
63 /* for command line parsing */
64 static struct hstate
* __initdata parsed_hstate
;
65 static unsigned long __initdata default_hstate_max_huge_pages
;
66 static bool __initdata parsed_valid_hugepagesz
= true;
67 static bool __initdata parsed_default_hugepagesz
;
70 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
71 * free_huge_pages, and surplus_huge_pages.
73 DEFINE_SPINLOCK(hugetlb_lock
);
76 * Serializes faults on the same logical page. This is used to
77 * prevent spurious OOMs when the hugepage pool is fully utilized.
79 static int num_fault_mutexes
;
80 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
82 /* Forward declaration */
83 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
85 static inline bool subpool_is_free(struct hugepage_subpool
*spool
)
89 if (spool
->max_hpages
!= -1)
90 return spool
->used_hpages
== 0;
91 if (spool
->min_hpages
!= -1)
92 return spool
->rsv_hpages
== spool
->min_hpages
;
97 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
99 spin_unlock(&spool
->lock
);
101 /* If no pages are used, and no other handles to the subpool
102 * remain, give up any reservations based on minimum size and
103 * free the subpool */
104 if (subpool_is_free(spool
)) {
105 if (spool
->min_hpages
!= -1)
106 hugetlb_acct_memory(spool
->hstate
,
112 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
115 struct hugepage_subpool
*spool
;
117 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
121 spin_lock_init(&spool
->lock
);
123 spool
->max_hpages
= max_hpages
;
125 spool
->min_hpages
= min_hpages
;
127 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
131 spool
->rsv_hpages
= min_hpages
;
136 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
138 spin_lock(&spool
->lock
);
139 BUG_ON(!spool
->count
);
141 unlock_or_release_subpool(spool
);
145 * Subpool accounting for allocating and reserving pages.
146 * Return -ENOMEM if there are not enough resources to satisfy the
147 * request. Otherwise, return the number of pages by which the
148 * global pools must be adjusted (upward). The returned value may
149 * only be different than the passed value (delta) in the case where
150 * a subpool minimum size must be maintained.
152 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
160 spin_lock(&spool
->lock
);
162 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
163 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
164 spool
->used_hpages
+= delta
;
171 /* minimum size accounting */
172 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
173 if (delta
> spool
->rsv_hpages
) {
175 * Asking for more reserves than those already taken on
176 * behalf of subpool. Return difference.
178 ret
= delta
- spool
->rsv_hpages
;
179 spool
->rsv_hpages
= 0;
181 ret
= 0; /* reserves already accounted for */
182 spool
->rsv_hpages
-= delta
;
187 spin_unlock(&spool
->lock
);
192 * Subpool accounting for freeing and unreserving pages.
193 * Return the number of global page reservations that must be dropped.
194 * The return value may only be different than the passed value (delta)
195 * in the case where a subpool minimum size must be maintained.
197 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
205 spin_lock(&spool
->lock
);
207 if (spool
->max_hpages
!= -1) /* maximum size accounting */
208 spool
->used_hpages
-= delta
;
210 /* minimum size accounting */
211 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
212 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
215 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
217 spool
->rsv_hpages
+= delta
;
218 if (spool
->rsv_hpages
> spool
->min_hpages
)
219 spool
->rsv_hpages
= spool
->min_hpages
;
223 * If hugetlbfs_put_super couldn't free spool due to an outstanding
224 * quota reference, free it now.
226 unlock_or_release_subpool(spool
);
231 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
233 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
236 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
238 return subpool_inode(file_inode(vma
->vm_file
));
241 /* Helper that removes a struct file_region from the resv_map cache and returns
244 static struct file_region
*
245 get_file_region_entry_from_cache(struct resv_map
*resv
, long from
, long to
)
247 struct file_region
*nrg
= NULL
;
249 VM_BUG_ON(resv
->region_cache_count
<= 0);
251 resv
->region_cache_count
--;
252 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
, link
);
253 list_del(&nrg
->link
);
261 static void copy_hugetlb_cgroup_uncharge_info(struct file_region
*nrg
,
262 struct file_region
*rg
)
264 #ifdef CONFIG_CGROUP_HUGETLB
265 nrg
->reservation_counter
= rg
->reservation_counter
;
272 /* Helper that records hugetlb_cgroup uncharge info. */
273 static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup
*h_cg
,
275 struct resv_map
*resv
,
276 struct file_region
*nrg
)
278 #ifdef CONFIG_CGROUP_HUGETLB
280 nrg
->reservation_counter
=
281 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
282 nrg
->css
= &h_cg
->css
;
284 * The caller will hold exactly one h_cg->css reference for the
285 * whole contiguous reservation region. But this area might be
286 * scattered when there are already some file_regions reside in
287 * it. As a result, many file_regions may share only one css
288 * reference. In order to ensure that one file_region must hold
289 * exactly one h_cg->css reference, we should do css_get for
290 * each file_region and leave the reference held by caller
294 if (!resv
->pages_per_hpage
)
295 resv
->pages_per_hpage
= pages_per_huge_page(h
);
296 /* pages_per_hpage should be the same for all entries in
299 VM_BUG_ON(resv
->pages_per_hpage
!= pages_per_huge_page(h
));
301 nrg
->reservation_counter
= NULL
;
307 static void put_uncharge_info(struct file_region
*rg
)
309 #ifdef CONFIG_CGROUP_HUGETLB
315 static bool has_same_uncharge_info(struct file_region
*rg
,
316 struct file_region
*org
)
318 #ifdef CONFIG_CGROUP_HUGETLB
320 rg
->reservation_counter
== org
->reservation_counter
&&
328 static void coalesce_file_region(struct resv_map
*resv
, struct file_region
*rg
)
330 struct file_region
*nrg
= NULL
, *prg
= NULL
;
332 prg
= list_prev_entry(rg
, link
);
333 if (&prg
->link
!= &resv
->regions
&& prg
->to
== rg
->from
&&
334 has_same_uncharge_info(prg
, rg
)) {
338 put_uncharge_info(rg
);
344 nrg
= list_next_entry(rg
, link
);
345 if (&nrg
->link
!= &resv
->regions
&& nrg
->from
== rg
->to
&&
346 has_same_uncharge_info(nrg
, rg
)) {
347 nrg
->from
= rg
->from
;
350 put_uncharge_info(rg
);
356 hugetlb_resv_map_add(struct resv_map
*map
, struct file_region
*rg
, long from
,
357 long to
, struct hstate
*h
, struct hugetlb_cgroup
*cg
,
358 long *regions_needed
)
360 struct file_region
*nrg
;
362 if (!regions_needed
) {
363 nrg
= get_file_region_entry_from_cache(map
, from
, to
);
364 record_hugetlb_cgroup_uncharge_info(cg
, h
, map
, nrg
);
365 list_add(&nrg
->link
, rg
->link
.prev
);
366 coalesce_file_region(map
, nrg
);
368 *regions_needed
+= 1;
374 * Must be called with resv->lock held.
376 * Calling this with regions_needed != NULL will count the number of pages
377 * to be added but will not modify the linked list. And regions_needed will
378 * indicate the number of file_regions needed in the cache to carry out to add
379 * the regions for this range.
381 static long add_reservation_in_range(struct resv_map
*resv
, long f
, long t
,
382 struct hugetlb_cgroup
*h_cg
,
383 struct hstate
*h
, long *regions_needed
)
386 struct list_head
*head
= &resv
->regions
;
387 long last_accounted_offset
= f
;
388 struct file_region
*rg
= NULL
, *trg
= NULL
;
393 /* In this loop, we essentially handle an entry for the range
394 * [last_accounted_offset, rg->from), at every iteration, with some
397 list_for_each_entry_safe(rg
, trg
, head
, link
) {
398 /* Skip irrelevant regions that start before our range. */
400 /* If this region ends after the last accounted offset,
401 * then we need to update last_accounted_offset.
403 if (rg
->to
> last_accounted_offset
)
404 last_accounted_offset
= rg
->to
;
408 /* When we find a region that starts beyond our range, we've
414 /* Add an entry for last_accounted_offset -> rg->from, and
415 * update last_accounted_offset.
417 if (rg
->from
> last_accounted_offset
)
418 add
+= hugetlb_resv_map_add(resv
, rg
,
419 last_accounted_offset
,
423 last_accounted_offset
= rg
->to
;
426 /* Handle the case where our range extends beyond
427 * last_accounted_offset.
429 if (last_accounted_offset
< t
)
430 add
+= hugetlb_resv_map_add(resv
, rg
, last_accounted_offset
,
431 t
, h
, h_cg
, regions_needed
);
437 /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
439 static int allocate_file_region_entries(struct resv_map
*resv
,
441 __must_hold(&resv
->lock
)
443 struct list_head allocated_regions
;
444 int to_allocate
= 0, i
= 0;
445 struct file_region
*trg
= NULL
, *rg
= NULL
;
447 VM_BUG_ON(regions_needed
< 0);
449 INIT_LIST_HEAD(&allocated_regions
);
452 * Check for sufficient descriptors in the cache to accommodate
453 * the number of in progress add operations plus regions_needed.
455 * This is a while loop because when we drop the lock, some other call
456 * to region_add or region_del may have consumed some region_entries,
457 * so we keep looping here until we finally have enough entries for
458 * (adds_in_progress + regions_needed).
460 while (resv
->region_cache_count
<
461 (resv
->adds_in_progress
+ regions_needed
)) {
462 to_allocate
= resv
->adds_in_progress
+ regions_needed
-
463 resv
->region_cache_count
;
465 /* At this point, we should have enough entries in the cache
466 * for all the existings adds_in_progress. We should only be
467 * needing to allocate for regions_needed.
469 VM_BUG_ON(resv
->region_cache_count
< resv
->adds_in_progress
);
471 spin_unlock(&resv
->lock
);
472 for (i
= 0; i
< to_allocate
; i
++) {
473 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
476 list_add(&trg
->link
, &allocated_regions
);
479 spin_lock(&resv
->lock
);
481 list_splice(&allocated_regions
, &resv
->region_cache
);
482 resv
->region_cache_count
+= to_allocate
;
488 list_for_each_entry_safe(rg
, trg
, &allocated_regions
, link
) {
496 * Add the huge page range represented by [f, t) to the reserve
497 * map. Regions will be taken from the cache to fill in this range.
498 * Sufficient regions should exist in the cache due to the previous
499 * call to region_chg with the same range, but in some cases the cache will not
500 * have sufficient entries due to races with other code doing region_add or
501 * region_del. The extra needed entries will be allocated.
503 * regions_needed is the out value provided by a previous call to region_chg.
505 * Return the number of new huge pages added to the map. This number is greater
506 * than or equal to zero. If file_region entries needed to be allocated for
507 * this operation and we were not able to allocate, it returns -ENOMEM.
508 * region_add of regions of length 1 never allocate file_regions and cannot
509 * fail; region_chg will always allocate at least 1 entry and a region_add for
510 * 1 page will only require at most 1 entry.
512 static long region_add(struct resv_map
*resv
, long f
, long t
,
513 long in_regions_needed
, struct hstate
*h
,
514 struct hugetlb_cgroup
*h_cg
)
516 long add
= 0, actual_regions_needed
= 0;
518 spin_lock(&resv
->lock
);
521 /* Count how many regions are actually needed to execute this add. */
522 add_reservation_in_range(resv
, f
, t
, NULL
, NULL
,
523 &actual_regions_needed
);
526 * Check for sufficient descriptors in the cache to accommodate
527 * this add operation. Note that actual_regions_needed may be greater
528 * than in_regions_needed, as the resv_map may have been modified since
529 * the region_chg call. In this case, we need to make sure that we
530 * allocate extra entries, such that we have enough for all the
531 * existing adds_in_progress, plus the excess needed for this
534 if (actual_regions_needed
> in_regions_needed
&&
535 resv
->region_cache_count
<
536 resv
->adds_in_progress
+
537 (actual_regions_needed
- in_regions_needed
)) {
538 /* region_add operation of range 1 should never need to
539 * allocate file_region entries.
541 VM_BUG_ON(t
- f
<= 1);
543 if (allocate_file_region_entries(
544 resv
, actual_regions_needed
- in_regions_needed
)) {
551 add
= add_reservation_in_range(resv
, f
, t
, h_cg
, h
, NULL
);
553 resv
->adds_in_progress
-= in_regions_needed
;
555 spin_unlock(&resv
->lock
);
561 * Examine the existing reserve map and determine how many
562 * huge pages in the specified range [f, t) are NOT currently
563 * represented. This routine is called before a subsequent
564 * call to region_add that will actually modify the reserve
565 * map to add the specified range [f, t). region_chg does
566 * not change the number of huge pages represented by the
567 * map. A number of new file_region structures is added to the cache as a
568 * placeholder, for the subsequent region_add call to use. At least 1
569 * file_region structure is added.
571 * out_regions_needed is the number of regions added to the
572 * resv->adds_in_progress. This value needs to be provided to a follow up call
573 * to region_add or region_abort for proper accounting.
575 * Returns the number of huge pages that need to be added to the existing
576 * reservation map for the range [f, t). This number is greater or equal to
577 * zero. -ENOMEM is returned if a new file_region structure or cache entry
578 * is needed and can not be allocated.
580 static long region_chg(struct resv_map
*resv
, long f
, long t
,
581 long *out_regions_needed
)
585 spin_lock(&resv
->lock
);
587 /* Count how many hugepages in this range are NOT represented. */
588 chg
= add_reservation_in_range(resv
, f
, t
, NULL
, NULL
,
591 if (*out_regions_needed
== 0)
592 *out_regions_needed
= 1;
594 if (allocate_file_region_entries(resv
, *out_regions_needed
))
597 resv
->adds_in_progress
+= *out_regions_needed
;
599 spin_unlock(&resv
->lock
);
604 * Abort the in progress add operation. The adds_in_progress field
605 * of the resv_map keeps track of the operations in progress between
606 * calls to region_chg and region_add. Operations are sometimes
607 * aborted after the call to region_chg. In such cases, region_abort
608 * is called to decrement the adds_in_progress counter. regions_needed
609 * is the value returned by the region_chg call, it is used to decrement
610 * the adds_in_progress counter.
612 * NOTE: The range arguments [f, t) are not needed or used in this
613 * routine. They are kept to make reading the calling code easier as
614 * arguments will match the associated region_chg call.
616 static void region_abort(struct resv_map
*resv
, long f
, long t
,
619 spin_lock(&resv
->lock
);
620 VM_BUG_ON(!resv
->region_cache_count
);
621 resv
->adds_in_progress
-= regions_needed
;
622 spin_unlock(&resv
->lock
);
626 * Delete the specified range [f, t) from the reserve map. If the
627 * t parameter is LONG_MAX, this indicates that ALL regions after f
628 * should be deleted. Locate the regions which intersect [f, t)
629 * and either trim, delete or split the existing regions.
631 * Returns the number of huge pages deleted from the reserve map.
632 * In the normal case, the return value is zero or more. In the
633 * case where a region must be split, a new region descriptor must
634 * be allocated. If the allocation fails, -ENOMEM will be returned.
635 * NOTE: If the parameter t == LONG_MAX, then we will never split
636 * a region and possibly return -ENOMEM. Callers specifying
637 * t == LONG_MAX do not need to check for -ENOMEM error.
639 static long region_del(struct resv_map
*resv
, long f
, long t
)
641 struct list_head
*head
= &resv
->regions
;
642 struct file_region
*rg
, *trg
;
643 struct file_region
*nrg
= NULL
;
647 spin_lock(&resv
->lock
);
648 list_for_each_entry_safe(rg
, trg
, head
, link
) {
650 * Skip regions before the range to be deleted. file_region
651 * ranges are normally of the form [from, to). However, there
652 * may be a "placeholder" entry in the map which is of the form
653 * (from, to) with from == to. Check for placeholder entries
654 * at the beginning of the range to be deleted.
656 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
662 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
664 * Check for an entry in the cache before dropping
665 * lock and attempting allocation.
668 resv
->region_cache_count
> resv
->adds_in_progress
) {
669 nrg
= list_first_entry(&resv
->region_cache
,
672 list_del(&nrg
->link
);
673 resv
->region_cache_count
--;
677 spin_unlock(&resv
->lock
);
678 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
685 hugetlb_cgroup_uncharge_file_region(
686 resv
, rg
, t
- f
, false);
688 /* New entry for end of split region */
692 copy_hugetlb_cgroup_uncharge_info(nrg
, rg
);
694 INIT_LIST_HEAD(&nrg
->link
);
696 /* Original entry is trimmed */
699 list_add(&nrg
->link
, &rg
->link
);
704 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
705 del
+= rg
->to
- rg
->from
;
706 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
707 rg
->to
- rg
->from
, true);
713 if (f
<= rg
->from
) { /* Trim beginning of region */
714 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
715 t
- rg
->from
, false);
719 } else { /* Trim end of region */
720 hugetlb_cgroup_uncharge_file_region(resv
, rg
,
728 spin_unlock(&resv
->lock
);
734 * A rare out of memory error was encountered which prevented removal of
735 * the reserve map region for a page. The huge page itself was free'ed
736 * and removed from the page cache. This routine will adjust the subpool
737 * usage count, and the global reserve count if needed. By incrementing
738 * these counts, the reserve map entry which could not be deleted will
739 * appear as a "reserved" entry instead of simply dangling with incorrect
742 void hugetlb_fix_reserve_counts(struct inode
*inode
)
744 struct hugepage_subpool
*spool
= subpool_inode(inode
);
747 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
749 struct hstate
*h
= hstate_inode(inode
);
751 hugetlb_acct_memory(h
, 1);
756 * Count and return the number of huge pages in the reserve map
757 * that intersect with the range [f, t).
759 static long region_count(struct resv_map
*resv
, long f
, long t
)
761 struct list_head
*head
= &resv
->regions
;
762 struct file_region
*rg
;
765 spin_lock(&resv
->lock
);
766 /* Locate each segment we overlap with, and count that overlap. */
767 list_for_each_entry(rg
, head
, link
) {
776 seg_from
= max(rg
->from
, f
);
777 seg_to
= min(rg
->to
, t
);
779 chg
+= seg_to
- seg_from
;
781 spin_unlock(&resv
->lock
);
787 * Convert the address within this vma to the page offset within
788 * the mapping, in pagecache page units; huge pages here.
790 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
791 struct vm_area_struct
*vma
, unsigned long address
)
793 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
794 (vma
->vm_pgoff
>> huge_page_order(h
));
797 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
798 unsigned long address
)
800 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
802 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
805 * Return the size of the pages allocated when backing a VMA. In the majority
806 * cases this will be same size as used by the page table entries.
808 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
810 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
811 return vma
->vm_ops
->pagesize(vma
);
814 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
817 * Return the page size being used by the MMU to back a VMA. In the majority
818 * of cases, the page size used by the kernel matches the MMU size. On
819 * architectures where it differs, an architecture-specific 'strong'
820 * version of this symbol is required.
822 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
824 return vma_kernel_pagesize(vma
);
828 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
829 * bits of the reservation map pointer, which are always clear due to
832 #define HPAGE_RESV_OWNER (1UL << 0)
833 #define HPAGE_RESV_UNMAPPED (1UL << 1)
834 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
837 * These helpers are used to track how many pages are reserved for
838 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
839 * is guaranteed to have their future faults succeed.
841 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
842 * the reserve counters are updated with the hugetlb_lock held. It is safe
843 * to reset the VMA at fork() time as it is not in use yet and there is no
844 * chance of the global counters getting corrupted as a result of the values.
846 * The private mapping reservation is represented in a subtly different
847 * manner to a shared mapping. A shared mapping has a region map associated
848 * with the underlying file, this region map represents the backing file
849 * pages which have ever had a reservation assigned which this persists even
850 * after the page is instantiated. A private mapping has a region map
851 * associated with the original mmap which is attached to all VMAs which
852 * reference it, this region map represents those offsets which have consumed
853 * reservation ie. where pages have been instantiated.
855 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
857 return (unsigned long)vma
->vm_private_data
;
860 static void set_vma_private_data(struct vm_area_struct
*vma
,
863 vma
->vm_private_data
= (void *)value
;
867 resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map
*resv_map
,
868 struct hugetlb_cgroup
*h_cg
,
871 #ifdef CONFIG_CGROUP_HUGETLB
873 resv_map
->reservation_counter
= NULL
;
874 resv_map
->pages_per_hpage
= 0;
875 resv_map
->css
= NULL
;
877 resv_map
->reservation_counter
=
878 &h_cg
->rsvd_hugepage
[hstate_index(h
)];
879 resv_map
->pages_per_hpage
= pages_per_huge_page(h
);
880 resv_map
->css
= &h_cg
->css
;
885 struct resv_map
*resv_map_alloc(void)
887 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
888 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
890 if (!resv_map
|| !rg
) {
896 kref_init(&resv_map
->refs
);
897 spin_lock_init(&resv_map
->lock
);
898 INIT_LIST_HEAD(&resv_map
->regions
);
900 resv_map
->adds_in_progress
= 0;
902 * Initialize these to 0. On shared mappings, 0's here indicate these
903 * fields don't do cgroup accounting. On private mappings, these will be
904 * re-initialized to the proper values, to indicate that hugetlb cgroup
905 * reservations are to be un-charged from here.
907 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, NULL
, NULL
);
909 INIT_LIST_HEAD(&resv_map
->region_cache
);
910 list_add(&rg
->link
, &resv_map
->region_cache
);
911 resv_map
->region_cache_count
= 1;
916 void resv_map_release(struct kref
*ref
)
918 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
919 struct list_head
*head
= &resv_map
->region_cache
;
920 struct file_region
*rg
, *trg
;
922 /* Clear out any active regions before we release the map. */
923 region_del(resv_map
, 0, LONG_MAX
);
925 /* ... and any entries left in the cache */
926 list_for_each_entry_safe(rg
, trg
, head
, link
) {
931 VM_BUG_ON(resv_map
->adds_in_progress
);
936 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
939 * At inode evict time, i_mapping may not point to the original
940 * address space within the inode. This original address space
941 * contains the pointer to the resv_map. So, always use the
942 * address space embedded within the inode.
943 * The VERY common case is inode->mapping == &inode->i_data but,
944 * this may not be true for device special inodes.
946 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
949 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
951 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
952 if (vma
->vm_flags
& VM_MAYSHARE
) {
953 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
954 struct inode
*inode
= mapping
->host
;
956 return inode_resv_map(inode
);
959 return (struct resv_map
*)(get_vma_private_data(vma
) &
964 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
966 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
967 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
969 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
970 HPAGE_RESV_MASK
) | (unsigned long)map
);
973 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
975 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
976 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
978 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
981 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
983 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
985 return (get_vma_private_data(vma
) & flag
) != 0;
988 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
989 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
991 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
992 if (!(vma
->vm_flags
& VM_MAYSHARE
))
993 vma
->vm_private_data
= (void *)0;
996 /* Returns true if the VMA has associated reserve pages */
997 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
999 if (vma
->vm_flags
& VM_NORESERVE
) {
1001 * This address is already reserved by other process(chg == 0),
1002 * so, we should decrement reserved count. Without decrementing,
1003 * reserve count remains after releasing inode, because this
1004 * allocated page will go into page cache and is regarded as
1005 * coming from reserved pool in releasing step. Currently, we
1006 * don't have any other solution to deal with this situation
1007 * properly, so add work-around here.
1009 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
1015 /* Shared mappings always use reserves */
1016 if (vma
->vm_flags
& VM_MAYSHARE
) {
1018 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1019 * be a region map for all pages. The only situation where
1020 * there is no region map is if a hole was punched via
1021 * fallocate. In this case, there really are no reserves to
1022 * use. This situation is indicated if chg != 0.
1031 * Only the process that called mmap() has reserves for
1034 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
1036 * Like the shared case above, a hole punch or truncate
1037 * could have been performed on the private mapping.
1038 * Examine the value of chg to determine if reserves
1039 * actually exist or were previously consumed.
1040 * Very Subtle - The value of chg comes from a previous
1041 * call to vma_needs_reserves(). The reserve map for
1042 * private mappings has different (opposite) semantics
1043 * than that of shared mappings. vma_needs_reserves()
1044 * has already taken this difference in semantics into
1045 * account. Therefore, the meaning of chg is the same
1046 * as in the shared case above. Code could easily be
1047 * combined, but keeping it separate draws attention to
1048 * subtle differences.
1059 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
1061 int nid
= page_to_nid(page
);
1062 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
1063 h
->free_huge_pages
++;
1064 h
->free_huge_pages_node
[nid
]++;
1065 SetHPageFreed(page
);
1068 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
1071 bool nocma
= !!(current
->flags
& PF_MEMALLOC_NOCMA
);
1073 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
) {
1074 if (nocma
&& is_migrate_cma_page(page
))
1077 if (PageHWPoison(page
))
1080 list_move(&page
->lru
, &h
->hugepage_activelist
);
1081 set_page_refcounted(page
);
1082 ClearHPageFreed(page
);
1083 h
->free_huge_pages
--;
1084 h
->free_huge_pages_node
[nid
]--;
1091 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
1094 unsigned int cpuset_mems_cookie
;
1095 struct zonelist
*zonelist
;
1098 int node
= NUMA_NO_NODE
;
1100 zonelist
= node_zonelist(nid
, gfp_mask
);
1103 cpuset_mems_cookie
= read_mems_allowed_begin();
1104 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
1107 if (!cpuset_zone_allowed(zone
, gfp_mask
))
1110 * no need to ask again on the same node. Pool is node rather than
1113 if (zone_to_nid(zone
) == node
)
1115 node
= zone_to_nid(zone
);
1117 page
= dequeue_huge_page_node_exact(h
, node
);
1121 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
1127 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
1128 struct vm_area_struct
*vma
,
1129 unsigned long address
, int avoid_reserve
,
1133 struct mempolicy
*mpol
;
1135 nodemask_t
*nodemask
;
1139 * A child process with MAP_PRIVATE mappings created by their parent
1140 * have no page reserves. This check ensures that reservations are
1141 * not "stolen". The child may still get SIGKILLed
1143 if (!vma_has_reserves(vma
, chg
) &&
1144 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1147 /* If reserves cannot be used, ensure enough pages are in the pool */
1148 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1151 gfp_mask
= htlb_alloc_mask(h
);
1152 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1153 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
1154 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
1155 SetHPageRestoreReserve(page
);
1156 h
->resv_huge_pages
--;
1159 mpol_cond_put(mpol
);
1167 * common helper functions for hstate_next_node_to_{alloc|free}.
1168 * We may have allocated or freed a huge page based on a different
1169 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1170 * be outside of *nodes_allowed. Ensure that we use an allowed
1171 * node for alloc or free.
1173 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1175 nid
= next_node_in(nid
, *nodes_allowed
);
1176 VM_BUG_ON(nid
>= MAX_NUMNODES
);
1181 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1183 if (!node_isset(nid
, *nodes_allowed
))
1184 nid
= next_node_allowed(nid
, nodes_allowed
);
1189 * returns the previously saved node ["this node"] from which to
1190 * allocate a persistent huge page for the pool and advance the
1191 * next node from which to allocate, handling wrap at end of node
1194 static int hstate_next_node_to_alloc(struct hstate
*h
,
1195 nodemask_t
*nodes_allowed
)
1199 VM_BUG_ON(!nodes_allowed
);
1201 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1202 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1208 * helper for free_pool_huge_page() - return the previously saved
1209 * node ["this node"] from which to free a huge page. Advance the
1210 * next node id whether or not we find a free huge page to free so
1211 * that the next attempt to free addresses the next node.
1213 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1217 VM_BUG_ON(!nodes_allowed
);
1219 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1220 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1225 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1226 for (nr_nodes = nodes_weight(*mask); \
1228 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1231 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1232 for (nr_nodes = nodes_weight(*mask); \
1234 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1237 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1238 static void destroy_compound_gigantic_page(struct page
*page
,
1242 int nr_pages
= 1 << order
;
1243 struct page
*p
= page
+ 1;
1245 atomic_set(compound_mapcount_ptr(page
), 0);
1246 atomic_set(compound_pincount_ptr(page
), 0);
1248 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1249 clear_compound_head(p
);
1250 set_page_refcounted(p
);
1253 set_compound_order(page
, 0);
1254 page
[1].compound_nr
= 0;
1255 __ClearPageHead(page
);
1258 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1261 * If the page isn't allocated using the cma allocator,
1262 * cma_release() returns false.
1265 if (cma_release(hugetlb_cma
[page_to_nid(page
)], page
, 1 << order
))
1269 free_contig_range(page_to_pfn(page
), 1 << order
);
1272 #ifdef CONFIG_CONTIG_ALLOC
1273 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1274 int nid
, nodemask_t
*nodemask
)
1276 unsigned long nr_pages
= 1UL << huge_page_order(h
);
1277 if (nid
== NUMA_NO_NODE
)
1278 nid
= numa_mem_id();
1285 if (hugetlb_cma
[nid
]) {
1286 page
= cma_alloc(hugetlb_cma
[nid
], nr_pages
,
1287 huge_page_order(h
), true);
1292 if (!(gfp_mask
& __GFP_THISNODE
)) {
1293 for_each_node_mask(node
, *nodemask
) {
1294 if (node
== nid
|| !hugetlb_cma
[node
])
1297 page
= cma_alloc(hugetlb_cma
[node
], nr_pages
,
1298 huge_page_order(h
), true);
1306 return alloc_contig_pages(nr_pages
, gfp_mask
, nid
, nodemask
);
1309 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1310 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1311 #else /* !CONFIG_CONTIG_ALLOC */
1312 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1313 int nid
, nodemask_t
*nodemask
)
1317 #endif /* CONFIG_CONTIG_ALLOC */
1319 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1320 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1321 int nid
, nodemask_t
*nodemask
)
1325 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1326 static inline void destroy_compound_gigantic_page(struct page
*page
,
1327 unsigned int order
) { }
1330 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1333 struct page
*subpage
= page
;
1335 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1339 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1340 for (i
= 0; i
< pages_per_huge_page(h
);
1341 i
++, subpage
= mem_map_next(subpage
, page
, i
)) {
1342 subpage
->flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1343 1 << PG_referenced
| 1 << PG_dirty
|
1344 1 << PG_active
| 1 << PG_private
|
1347 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1348 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page
), page
);
1349 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1350 set_page_refcounted(page
);
1351 if (hstate_is_gigantic(h
)) {
1353 * Temporarily drop the hugetlb_lock, because
1354 * we might block in free_gigantic_page().
1356 spin_unlock(&hugetlb_lock
);
1357 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1358 free_gigantic_page(page
, huge_page_order(h
));
1359 spin_lock(&hugetlb_lock
);
1361 __free_pages(page
, huge_page_order(h
));
1365 struct hstate
*size_to_hstate(unsigned long size
)
1369 for_each_hstate(h
) {
1370 if (huge_page_size(h
) == size
)
1376 static void __free_huge_page(struct page
*page
)
1379 * Can't pass hstate in here because it is called from the
1380 * compound page destructor.
1382 struct hstate
*h
= page_hstate(page
);
1383 int nid
= page_to_nid(page
);
1384 struct hugepage_subpool
*spool
= hugetlb_page_subpool(page
);
1385 bool restore_reserve
;
1387 VM_BUG_ON_PAGE(page_count(page
), page
);
1388 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1390 hugetlb_set_page_subpool(page
, NULL
);
1391 page
->mapping
= NULL
;
1392 restore_reserve
= HPageRestoreReserve(page
);
1393 ClearHPageRestoreReserve(page
);
1396 * If HPageRestoreReserve was set on page, page allocation consumed a
1397 * reservation. If the page was associated with a subpool, there
1398 * would have been a page reserved in the subpool before allocation
1399 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1400 * reservation, do not call hugepage_subpool_put_pages() as this will
1401 * remove the reserved page from the subpool.
1403 if (!restore_reserve
) {
1405 * A return code of zero implies that the subpool will be
1406 * under its minimum size if the reservation is not restored
1407 * after page is free. Therefore, force restore_reserve
1410 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1411 restore_reserve
= true;
1414 spin_lock(&hugetlb_lock
);
1415 ClearHPageMigratable(page
);
1416 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1417 pages_per_huge_page(h
), page
);
1418 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h
),
1419 pages_per_huge_page(h
), page
);
1420 if (restore_reserve
)
1421 h
->resv_huge_pages
++;
1423 if (HPageTemporary(page
)) {
1424 list_del(&page
->lru
);
1425 ClearHPageTemporary(page
);
1426 update_and_free_page(h
, page
);
1427 } else if (h
->surplus_huge_pages_node
[nid
]) {
1428 /* remove the page from active list */
1429 list_del(&page
->lru
);
1430 update_and_free_page(h
, page
);
1431 h
->surplus_huge_pages
--;
1432 h
->surplus_huge_pages_node
[nid
]--;
1434 arch_clear_hugepage_flags(page
);
1435 enqueue_huge_page(h
, page
);
1437 spin_unlock(&hugetlb_lock
);
1441 * As free_huge_page() can be called from a non-task context, we have
1442 * to defer the actual freeing in a workqueue to prevent potential
1443 * hugetlb_lock deadlock.
1445 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1446 * be freed and frees them one-by-one. As the page->mapping pointer is
1447 * going to be cleared in __free_huge_page() anyway, it is reused as the
1448 * llist_node structure of a lockless linked list of huge pages to be freed.
1450 static LLIST_HEAD(hpage_freelist
);
1452 static void free_hpage_workfn(struct work_struct
*work
)
1454 struct llist_node
*node
;
1457 node
= llist_del_all(&hpage_freelist
);
1460 page
= container_of((struct address_space
**)node
,
1461 struct page
, mapping
);
1463 __free_huge_page(page
);
1466 static DECLARE_WORK(free_hpage_work
, free_hpage_workfn
);
1468 void free_huge_page(struct page
*page
)
1471 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1475 * Only call schedule_work() if hpage_freelist is previously
1476 * empty. Otherwise, schedule_work() had been called but the
1477 * workfn hasn't retrieved the list yet.
1479 if (llist_add((struct llist_node
*)&page
->mapping
,
1481 schedule_work(&free_hpage_work
);
1485 __free_huge_page(page
);
1488 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1490 INIT_LIST_HEAD(&page
->lru
);
1491 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1492 hugetlb_set_page_subpool(page
, NULL
);
1493 set_hugetlb_cgroup(page
, NULL
);
1494 set_hugetlb_cgroup_rsvd(page
, NULL
);
1495 spin_lock(&hugetlb_lock
);
1497 h
->nr_huge_pages_node
[nid
]++;
1498 ClearHPageFreed(page
);
1499 spin_unlock(&hugetlb_lock
);
1502 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1505 int nr_pages
= 1 << order
;
1506 struct page
*p
= page
+ 1;
1508 /* we rely on prep_new_huge_page to set the destructor */
1509 set_compound_order(page
, order
);
1510 __ClearPageReserved(page
);
1511 __SetPageHead(page
);
1512 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1514 * For gigantic hugepages allocated through bootmem at
1515 * boot, it's safer to be consistent with the not-gigantic
1516 * hugepages and clear the PG_reserved bit from all tail pages
1517 * too. Otherwise drivers using get_user_pages() to access tail
1518 * pages may get the reference counting wrong if they see
1519 * PG_reserved set on a tail page (despite the head page not
1520 * having PG_reserved set). Enforcing this consistency between
1521 * head and tail pages allows drivers to optimize away a check
1522 * on the head page when they need know if put_page() is needed
1523 * after get_user_pages().
1525 __ClearPageReserved(p
);
1526 set_page_count(p
, 0);
1527 set_compound_head(p
, page
);
1529 atomic_set(compound_mapcount_ptr(page
), -1);
1530 atomic_set(compound_pincount_ptr(page
), 0);
1534 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1535 * transparent huge pages. See the PageTransHuge() documentation for more
1538 int PageHuge(struct page
*page
)
1540 if (!PageCompound(page
))
1543 page
= compound_head(page
);
1544 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1546 EXPORT_SYMBOL_GPL(PageHuge
);
1549 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1550 * normal or transparent huge pages.
1552 int PageHeadHuge(struct page
*page_head
)
1554 if (!PageHead(page_head
))
1557 return page_head
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1561 * Find and lock address space (mapping) in write mode.
1563 * Upon entry, the page is locked which means that page_mapping() is
1564 * stable. Due to locking order, we can only trylock_write. If we can
1565 * not get the lock, simply return NULL to caller.
1567 struct address_space
*hugetlb_page_mapping_lock_write(struct page
*hpage
)
1569 struct address_space
*mapping
= page_mapping(hpage
);
1574 if (i_mmap_trylock_write(mapping
))
1580 pgoff_t
__basepage_index(struct page
*page
)
1582 struct page
*page_head
= compound_head(page
);
1583 pgoff_t index
= page_index(page_head
);
1584 unsigned long compound_idx
;
1586 if (!PageHuge(page_head
))
1587 return page_index(page
);
1589 if (compound_order(page_head
) >= MAX_ORDER
)
1590 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1592 compound_idx
= page
- page_head
;
1594 return (index
<< compound_order(page_head
)) + compound_idx
;
1597 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1598 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1599 nodemask_t
*node_alloc_noretry
)
1601 int order
= huge_page_order(h
);
1603 bool alloc_try_hard
= true;
1606 * By default we always try hard to allocate the page with
1607 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1608 * a loop (to adjust global huge page counts) and previous allocation
1609 * failed, do not continue to try hard on the same node. Use the
1610 * node_alloc_noretry bitmap to manage this state information.
1612 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1613 alloc_try_hard
= false;
1614 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1616 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1617 if (nid
== NUMA_NO_NODE
)
1618 nid
= numa_mem_id();
1619 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1621 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1623 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1626 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1627 * indicates an overall state change. Clear bit so that we resume
1628 * normal 'try hard' allocations.
1630 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1631 node_clear(nid
, *node_alloc_noretry
);
1634 * If we tried hard to get a page but failed, set bit so that
1635 * subsequent attempts will not try as hard until there is an
1636 * overall state change.
1638 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1639 node_set(nid
, *node_alloc_noretry
);
1645 * Common helper to allocate a fresh hugetlb page. All specific allocators
1646 * should use this function to get new hugetlb pages
1648 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1649 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1650 nodemask_t
*node_alloc_noretry
)
1654 if (hstate_is_gigantic(h
))
1655 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1657 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1658 nid
, nmask
, node_alloc_noretry
);
1662 if (hstate_is_gigantic(h
))
1663 prep_compound_gigantic_page(page
, huge_page_order(h
));
1664 prep_new_huge_page(h
, page
, page_to_nid(page
));
1670 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1673 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1674 nodemask_t
*node_alloc_noretry
)
1678 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1680 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1681 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1682 node_alloc_noretry
);
1690 put_page(page
); /* free it into the hugepage allocator */
1696 * Free huge page from pool from next node to free.
1697 * Attempt to keep persistent huge pages more or less
1698 * balanced over allowed nodes.
1699 * Called with hugetlb_lock locked.
1701 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1707 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1709 * If we're returning unused surplus pages, only examine
1710 * nodes with surplus pages.
1712 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1713 !list_empty(&h
->hugepage_freelists
[node
])) {
1715 list_entry(h
->hugepage_freelists
[node
].next
,
1717 list_del(&page
->lru
);
1718 h
->free_huge_pages
--;
1719 h
->free_huge_pages_node
[node
]--;
1721 h
->surplus_huge_pages
--;
1722 h
->surplus_huge_pages_node
[node
]--;
1724 update_and_free_page(h
, page
);
1734 * Dissolve a given free hugepage into free buddy pages. This function does
1735 * nothing for in-use hugepages and non-hugepages.
1736 * This function returns values like below:
1738 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1739 * (allocated or reserved.)
1740 * 0: successfully dissolved free hugepages or the page is not a
1741 * hugepage (considered as already dissolved)
1743 int dissolve_free_huge_page(struct page
*page
)
1748 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1749 if (!PageHuge(page
))
1752 spin_lock(&hugetlb_lock
);
1753 if (!PageHuge(page
)) {
1758 if (!page_count(page
)) {
1759 struct page
*head
= compound_head(page
);
1760 struct hstate
*h
= page_hstate(head
);
1761 int nid
= page_to_nid(head
);
1762 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1766 * We should make sure that the page is already on the free list
1767 * when it is dissolved.
1769 if (unlikely(!HPageFreed(head
))) {
1770 spin_unlock(&hugetlb_lock
);
1774 * Theoretically, we should return -EBUSY when we
1775 * encounter this race. In fact, we have a chance
1776 * to successfully dissolve the page if we do a
1777 * retry. Because the race window is quite small.
1778 * If we seize this opportunity, it is an optimization
1779 * for increasing the success rate of dissolving page.
1785 * Move PageHWPoison flag from head page to the raw error page,
1786 * which makes any subpages rather than the error page reusable.
1788 if (PageHWPoison(head
) && page
!= head
) {
1789 SetPageHWPoison(page
);
1790 ClearPageHWPoison(head
);
1792 list_del(&head
->lru
);
1793 h
->free_huge_pages
--;
1794 h
->free_huge_pages_node
[nid
]--;
1795 h
->max_huge_pages
--;
1796 update_and_free_page(h
, head
);
1800 spin_unlock(&hugetlb_lock
);
1805 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1806 * make specified memory blocks removable from the system.
1807 * Note that this will dissolve a free gigantic hugepage completely, if any
1808 * part of it lies within the given range.
1809 * Also note that if dissolve_free_huge_page() returns with an error, all
1810 * free hugepages that were dissolved before that error are lost.
1812 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1818 if (!hugepages_supported())
1821 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1822 page
= pfn_to_page(pfn
);
1823 rc
= dissolve_free_huge_page(page
);
1832 * Allocates a fresh surplus page from the page allocator.
1834 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1835 int nid
, nodemask_t
*nmask
)
1837 struct page
*page
= NULL
;
1839 if (hstate_is_gigantic(h
))
1842 spin_lock(&hugetlb_lock
);
1843 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1845 spin_unlock(&hugetlb_lock
);
1847 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1851 spin_lock(&hugetlb_lock
);
1853 * We could have raced with the pool size change.
1854 * Double check that and simply deallocate the new page
1855 * if we would end up overcommiting the surpluses. Abuse
1856 * temporary page to workaround the nasty free_huge_page
1859 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1860 SetHPageTemporary(page
);
1861 spin_unlock(&hugetlb_lock
);
1865 h
->surplus_huge_pages
++;
1866 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1870 spin_unlock(&hugetlb_lock
);
1875 static struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1876 int nid
, nodemask_t
*nmask
)
1880 if (hstate_is_gigantic(h
))
1883 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1888 * We do not account these pages as surplus because they are only
1889 * temporary and will be released properly on the last reference
1891 SetHPageTemporary(page
);
1897 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1900 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1901 struct vm_area_struct
*vma
, unsigned long addr
)
1904 struct mempolicy
*mpol
;
1905 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1907 nodemask_t
*nodemask
;
1909 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1910 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1911 mpol_cond_put(mpol
);
1916 /* page migration callback function */
1917 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1918 nodemask_t
*nmask
, gfp_t gfp_mask
)
1920 spin_lock(&hugetlb_lock
);
1921 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1924 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1926 spin_unlock(&hugetlb_lock
);
1930 spin_unlock(&hugetlb_lock
);
1932 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1935 /* mempolicy aware migration callback */
1936 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
1937 unsigned long address
)
1939 struct mempolicy
*mpol
;
1940 nodemask_t
*nodemask
;
1945 gfp_mask
= htlb_alloc_mask(h
);
1946 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1947 page
= alloc_huge_page_nodemask(h
, node
, nodemask
, gfp_mask
);
1948 mpol_cond_put(mpol
);
1954 * Increase the hugetlb pool such that it can accommodate a reservation
1957 static int gather_surplus_pages(struct hstate
*h
, long delta
)
1958 __must_hold(&hugetlb_lock
)
1960 struct list_head surplus_list
;
1961 struct page
*page
, *tmp
;
1964 long needed
, allocated
;
1965 bool alloc_ok
= true;
1967 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1969 h
->resv_huge_pages
+= delta
;
1974 INIT_LIST_HEAD(&surplus_list
);
1978 spin_unlock(&hugetlb_lock
);
1979 for (i
= 0; i
< needed
; i
++) {
1980 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
1981 NUMA_NO_NODE
, NULL
);
1986 list_add(&page
->lru
, &surplus_list
);
1992 * After retaking hugetlb_lock, we need to recalculate 'needed'
1993 * because either resv_huge_pages or free_huge_pages may have changed.
1995 spin_lock(&hugetlb_lock
);
1996 needed
= (h
->resv_huge_pages
+ delta
) -
1997 (h
->free_huge_pages
+ allocated
);
2002 * We were not able to allocate enough pages to
2003 * satisfy the entire reservation so we free what
2004 * we've allocated so far.
2009 * The surplus_list now contains _at_least_ the number of extra pages
2010 * needed to accommodate the reservation. Add the appropriate number
2011 * of pages to the hugetlb pool and free the extras back to the buddy
2012 * allocator. Commit the entire reservation here to prevent another
2013 * process from stealing the pages as they are added to the pool but
2014 * before they are reserved.
2016 needed
+= allocated
;
2017 h
->resv_huge_pages
+= delta
;
2020 /* Free the needed pages to the hugetlb pool */
2021 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
2027 * This page is now managed by the hugetlb allocator and has
2028 * no users -- drop the buddy allocator's reference.
2030 zeroed
= put_page_testzero(page
);
2031 VM_BUG_ON_PAGE(!zeroed
, page
);
2032 enqueue_huge_page(h
, page
);
2035 spin_unlock(&hugetlb_lock
);
2037 /* Free unnecessary surplus pages to the buddy allocator */
2038 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
2040 spin_lock(&hugetlb_lock
);
2046 * This routine has two main purposes:
2047 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2048 * in unused_resv_pages. This corresponds to the prior adjustments made
2049 * to the associated reservation map.
2050 * 2) Free any unused surplus pages that may have been allocated to satisfy
2051 * the reservation. As many as unused_resv_pages may be freed.
2053 * Called with hugetlb_lock held. However, the lock could be dropped (and
2054 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2055 * we must make sure nobody else can claim pages we are in the process of
2056 * freeing. Do this by ensuring resv_huge_page always is greater than the
2057 * number of huge pages we plan to free when dropping the lock.
2059 static void return_unused_surplus_pages(struct hstate
*h
,
2060 unsigned long unused_resv_pages
)
2062 unsigned long nr_pages
;
2064 /* Cannot return gigantic pages currently */
2065 if (hstate_is_gigantic(h
))
2069 * Part (or even all) of the reservation could have been backed
2070 * by pre-allocated pages. Only free surplus pages.
2072 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
2075 * We want to release as many surplus pages as possible, spread
2076 * evenly across all nodes with memory. Iterate across these nodes
2077 * until we can no longer free unreserved surplus pages. This occurs
2078 * when the nodes with surplus pages have no free pages.
2079 * free_pool_huge_page() will balance the freed pages across the
2080 * on-line nodes with memory and will handle the hstate accounting.
2082 * Note that we decrement resv_huge_pages as we free the pages. If
2083 * we drop the lock, resv_huge_pages will still be sufficiently large
2084 * to cover subsequent pages we may free.
2086 while (nr_pages
--) {
2087 h
->resv_huge_pages
--;
2088 unused_resv_pages
--;
2089 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
2091 cond_resched_lock(&hugetlb_lock
);
2095 /* Fully uncommit the reservation */
2096 h
->resv_huge_pages
-= unused_resv_pages
;
2101 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2102 * are used by the huge page allocation routines to manage reservations.
2104 * vma_needs_reservation is called to determine if the huge page at addr
2105 * within the vma has an associated reservation. If a reservation is
2106 * needed, the value 1 is returned. The caller is then responsible for
2107 * managing the global reservation and subpool usage counts. After
2108 * the huge page has been allocated, vma_commit_reservation is called
2109 * to add the page to the reservation map. If the page allocation fails,
2110 * the reservation must be ended instead of committed. vma_end_reservation
2111 * is called in such cases.
2113 * In the normal case, vma_commit_reservation returns the same value
2114 * as the preceding vma_needs_reservation call. The only time this
2115 * is not the case is if a reserve map was changed between calls. It
2116 * is the responsibility of the caller to notice the difference and
2117 * take appropriate action.
2119 * vma_add_reservation is used in error paths where a reservation must
2120 * be restored when a newly allocated huge page must be freed. It is
2121 * to be called after calling vma_needs_reservation to determine if a
2122 * reservation exists.
2124 enum vma_resv_mode
{
2130 static long __vma_reservation_common(struct hstate
*h
,
2131 struct vm_area_struct
*vma
, unsigned long addr
,
2132 enum vma_resv_mode mode
)
2134 struct resv_map
*resv
;
2137 long dummy_out_regions_needed
;
2139 resv
= vma_resv_map(vma
);
2143 idx
= vma_hugecache_offset(h
, vma
, addr
);
2145 case VMA_NEEDS_RESV
:
2146 ret
= region_chg(resv
, idx
, idx
+ 1, &dummy_out_regions_needed
);
2147 /* We assume that vma_reservation_* routines always operate on
2148 * 1 page, and that adding to resv map a 1 page entry can only
2149 * ever require 1 region.
2151 VM_BUG_ON(dummy_out_regions_needed
!= 1);
2153 case VMA_COMMIT_RESV
:
2154 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2155 /* region_add calls of range 1 should never fail. */
2159 region_abort(resv
, idx
, idx
+ 1, 1);
2163 if (vma
->vm_flags
& VM_MAYSHARE
) {
2164 ret
= region_add(resv
, idx
, idx
+ 1, 1, NULL
, NULL
);
2165 /* region_add calls of range 1 should never fail. */
2168 region_abort(resv
, idx
, idx
+ 1, 1);
2169 ret
= region_del(resv
, idx
, idx
+ 1);
2176 if (vma
->vm_flags
& VM_MAYSHARE
)
2178 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
2180 * In most cases, reserves always exist for private mappings.
2181 * However, a file associated with mapping could have been
2182 * hole punched or truncated after reserves were consumed.
2183 * As subsequent fault on such a range will not use reserves.
2184 * Subtle - The reserve map for private mappings has the
2185 * opposite meaning than that of shared mappings. If NO
2186 * entry is in the reserve map, it means a reservation exists.
2187 * If an entry exists in the reserve map, it means the
2188 * reservation has already been consumed. As a result, the
2189 * return value of this routine is the opposite of the
2190 * value returned from reserve map manipulation routines above.
2198 return ret
< 0 ? ret
: 0;
2201 static long vma_needs_reservation(struct hstate
*h
,
2202 struct vm_area_struct
*vma
, unsigned long addr
)
2204 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
2207 static long vma_commit_reservation(struct hstate
*h
,
2208 struct vm_area_struct
*vma
, unsigned long addr
)
2210 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
2213 static void vma_end_reservation(struct hstate
*h
,
2214 struct vm_area_struct
*vma
, unsigned long addr
)
2216 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
2219 static long vma_add_reservation(struct hstate
*h
,
2220 struct vm_area_struct
*vma
, unsigned long addr
)
2222 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
2226 * This routine is called to restore a reservation on error paths. In the
2227 * specific error paths, a huge page was allocated (via alloc_huge_page)
2228 * and is about to be freed. If a reservation for the page existed,
2229 * alloc_huge_page would have consumed the reservation and set
2230 * HPageRestoreReserve in the newly allocated page. When the page is freed
2231 * via free_huge_page, the global reservation count will be incremented if
2232 * HPageRestoreReserve is set. However, free_huge_page can not adjust the
2233 * reserve map. Adjust the reserve map here to be consistent with global
2234 * reserve count adjustments to be made by free_huge_page.
2236 static void restore_reserve_on_error(struct hstate
*h
,
2237 struct vm_area_struct
*vma
, unsigned long address
,
2240 if (unlikely(HPageRestoreReserve(page
))) {
2241 long rc
= vma_needs_reservation(h
, vma
, address
);
2243 if (unlikely(rc
< 0)) {
2245 * Rare out of memory condition in reserve map
2246 * manipulation. Clear HPageRestoreReserve so that
2247 * global reserve count will not be incremented
2248 * by free_huge_page. This will make it appear
2249 * as though the reservation for this page was
2250 * consumed. This may prevent the task from
2251 * faulting in the page at a later time. This
2252 * is better than inconsistent global huge page
2253 * accounting of reserve counts.
2255 ClearHPageRestoreReserve(page
);
2257 rc
= vma_add_reservation(h
, vma
, address
);
2258 if (unlikely(rc
< 0))
2260 * See above comment about rare out of
2263 ClearHPageRestoreReserve(page
);
2265 vma_end_reservation(h
, vma
, address
);
2269 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2270 unsigned long addr
, int avoid_reserve
)
2272 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2273 struct hstate
*h
= hstate_vma(vma
);
2275 long map_chg
, map_commit
;
2278 struct hugetlb_cgroup
*h_cg
;
2279 bool deferred_reserve
;
2281 idx
= hstate_index(h
);
2283 * Examine the region/reserve map to determine if the process
2284 * has a reservation for the page to be allocated. A return
2285 * code of zero indicates a reservation exists (no change).
2287 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2289 return ERR_PTR(-ENOMEM
);
2292 * Processes that did not create the mapping will have no
2293 * reserves as indicated by the region/reserve map. Check
2294 * that the allocation will not exceed the subpool limit.
2295 * Allocations for MAP_NORESERVE mappings also need to be
2296 * checked against any subpool limit.
2298 if (map_chg
|| avoid_reserve
) {
2299 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2301 vma_end_reservation(h
, vma
, addr
);
2302 return ERR_PTR(-ENOSPC
);
2306 * Even though there was no reservation in the region/reserve
2307 * map, there could be reservations associated with the
2308 * subpool that can be used. This would be indicated if the
2309 * return value of hugepage_subpool_get_pages() is zero.
2310 * However, if avoid_reserve is specified we still avoid even
2311 * the subpool reservations.
2317 /* If this allocation is not consuming a reservation, charge it now.
2319 deferred_reserve
= map_chg
|| avoid_reserve
|| !vma_resv_map(vma
);
2320 if (deferred_reserve
) {
2321 ret
= hugetlb_cgroup_charge_cgroup_rsvd(
2322 idx
, pages_per_huge_page(h
), &h_cg
);
2324 goto out_subpool_put
;
2327 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2329 goto out_uncharge_cgroup_reservation
;
2331 spin_lock(&hugetlb_lock
);
2333 * glb_chg is passed to indicate whether or not a page must be taken
2334 * from the global free pool (global change). gbl_chg == 0 indicates
2335 * a reservation exists for the allocation.
2337 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2339 spin_unlock(&hugetlb_lock
);
2340 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2342 goto out_uncharge_cgroup
;
2343 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2344 SetHPageRestoreReserve(page
);
2345 h
->resv_huge_pages
--;
2347 spin_lock(&hugetlb_lock
);
2348 list_add(&page
->lru
, &h
->hugepage_activelist
);
2351 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2352 /* If allocation is not consuming a reservation, also store the
2353 * hugetlb_cgroup pointer on the page.
2355 if (deferred_reserve
) {
2356 hugetlb_cgroup_commit_charge_rsvd(idx
, pages_per_huge_page(h
),
2360 spin_unlock(&hugetlb_lock
);
2362 hugetlb_set_page_subpool(page
, spool
);
2364 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2365 if (unlikely(map_chg
> map_commit
)) {
2367 * The page was added to the reservation map between
2368 * vma_needs_reservation and vma_commit_reservation.
2369 * This indicates a race with hugetlb_reserve_pages.
2370 * Adjust for the subpool count incremented above AND
2371 * in hugetlb_reserve_pages for the same page. Also,
2372 * the reservation count added in hugetlb_reserve_pages
2373 * no longer applies.
2377 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2378 hugetlb_acct_memory(h
, -rsv_adjust
);
2379 if (deferred_reserve
)
2380 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h
),
2381 pages_per_huge_page(h
), page
);
2385 out_uncharge_cgroup
:
2386 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2387 out_uncharge_cgroup_reservation
:
2388 if (deferred_reserve
)
2389 hugetlb_cgroup_uncharge_cgroup_rsvd(idx
, pages_per_huge_page(h
),
2392 if (map_chg
|| avoid_reserve
)
2393 hugepage_subpool_put_pages(spool
, 1);
2394 vma_end_reservation(h
, vma
, addr
);
2395 return ERR_PTR(-ENOSPC
);
2398 int alloc_bootmem_huge_page(struct hstate
*h
)
2399 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2400 int __alloc_bootmem_huge_page(struct hstate
*h
)
2402 struct huge_bootmem_page
*m
;
2405 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2408 addr
= memblock_alloc_try_nid_raw(
2409 huge_page_size(h
), huge_page_size(h
),
2410 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2413 * Use the beginning of the huge page to store the
2414 * huge_bootmem_page struct (until gather_bootmem
2415 * puts them into the mem_map).
2424 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2425 /* Put them into a private list first because mem_map is not up yet */
2426 INIT_LIST_HEAD(&m
->list
);
2427 list_add(&m
->list
, &huge_boot_pages
);
2432 static void __init
prep_compound_huge_page(struct page
*page
,
2435 if (unlikely(order
> (MAX_ORDER
- 1)))
2436 prep_compound_gigantic_page(page
, order
);
2438 prep_compound_page(page
, order
);
2441 /* Put bootmem huge pages into the standard lists after mem_map is up */
2442 static void __init
gather_bootmem_prealloc(void)
2444 struct huge_bootmem_page
*m
;
2446 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2447 struct page
*page
= virt_to_page(m
);
2448 struct hstate
*h
= m
->hstate
;
2450 WARN_ON(page_count(page
) != 1);
2451 prep_compound_huge_page(page
, huge_page_order(h
));
2452 WARN_ON(PageReserved(page
));
2453 prep_new_huge_page(h
, page
, page_to_nid(page
));
2454 put_page(page
); /* free it into the hugepage allocator */
2457 * If we had gigantic hugepages allocated at boot time, we need
2458 * to restore the 'stolen' pages to totalram_pages in order to
2459 * fix confusing memory reports from free(1) and another
2460 * side-effects, like CommitLimit going negative.
2462 if (hstate_is_gigantic(h
))
2463 adjust_managed_page_count(page
, pages_per_huge_page(h
));
2468 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2471 nodemask_t
*node_alloc_noretry
;
2473 if (!hstate_is_gigantic(h
)) {
2475 * Bit mask controlling how hard we retry per-node allocations.
2476 * Ignore errors as lower level routines can deal with
2477 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2478 * time, we are likely in bigger trouble.
2480 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2483 /* allocations done at boot time */
2484 node_alloc_noretry
= NULL
;
2487 /* bit mask controlling how hard we retry per-node allocations */
2488 if (node_alloc_noretry
)
2489 nodes_clear(*node_alloc_noretry
);
2491 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2492 if (hstate_is_gigantic(h
)) {
2493 if (hugetlb_cma_size
) {
2494 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2497 if (!alloc_bootmem_huge_page(h
))
2499 } else if (!alloc_pool_huge_page(h
,
2500 &node_states
[N_MEMORY
],
2501 node_alloc_noretry
))
2505 if (i
< h
->max_huge_pages
) {
2508 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2509 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2510 h
->max_huge_pages
, buf
, i
);
2511 h
->max_huge_pages
= i
;
2514 kfree(node_alloc_noretry
);
2517 static void __init
hugetlb_init_hstates(void)
2521 for_each_hstate(h
) {
2522 if (minimum_order
> huge_page_order(h
))
2523 minimum_order
= huge_page_order(h
);
2525 /* oversize hugepages were init'ed in early boot */
2526 if (!hstate_is_gigantic(h
))
2527 hugetlb_hstate_alloc_pages(h
);
2529 VM_BUG_ON(minimum_order
== UINT_MAX
);
2532 static void __init
report_hugepages(void)
2536 for_each_hstate(h
) {
2539 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2540 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2541 buf
, h
->free_huge_pages
);
2545 #ifdef CONFIG_HIGHMEM
2546 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2547 nodemask_t
*nodes_allowed
)
2551 if (hstate_is_gigantic(h
))
2554 for_each_node_mask(i
, *nodes_allowed
) {
2555 struct page
*page
, *next
;
2556 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2557 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2558 if (count
>= h
->nr_huge_pages
)
2560 if (PageHighMem(page
))
2562 list_del(&page
->lru
);
2563 update_and_free_page(h
, page
);
2564 h
->free_huge_pages
--;
2565 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2570 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2571 nodemask_t
*nodes_allowed
)
2577 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2578 * balanced by operating on them in a round-robin fashion.
2579 * Returns 1 if an adjustment was made.
2581 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2586 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2589 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2590 if (h
->surplus_huge_pages_node
[node
])
2594 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2595 if (h
->surplus_huge_pages_node
[node
] <
2596 h
->nr_huge_pages_node
[node
])
2603 h
->surplus_huge_pages
+= delta
;
2604 h
->surplus_huge_pages_node
[node
] += delta
;
2608 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2609 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2610 nodemask_t
*nodes_allowed
)
2612 unsigned long min_count
, ret
;
2613 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2616 * Bit mask controlling how hard we retry per-node allocations.
2617 * If we can not allocate the bit mask, do not attempt to allocate
2618 * the requested huge pages.
2620 if (node_alloc_noretry
)
2621 nodes_clear(*node_alloc_noretry
);
2625 spin_lock(&hugetlb_lock
);
2628 * Check for a node specific request.
2629 * Changing node specific huge page count may require a corresponding
2630 * change to the global count. In any case, the passed node mask
2631 * (nodes_allowed) will restrict alloc/free to the specified node.
2633 if (nid
!= NUMA_NO_NODE
) {
2634 unsigned long old_count
= count
;
2636 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2638 * User may have specified a large count value which caused the
2639 * above calculation to overflow. In this case, they wanted
2640 * to allocate as many huge pages as possible. Set count to
2641 * largest possible value to align with their intention.
2643 if (count
< old_count
)
2648 * Gigantic pages runtime allocation depend on the capability for large
2649 * page range allocation.
2650 * If the system does not provide this feature, return an error when
2651 * the user tries to allocate gigantic pages but let the user free the
2652 * boottime allocated gigantic pages.
2654 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2655 if (count
> persistent_huge_pages(h
)) {
2656 spin_unlock(&hugetlb_lock
);
2657 NODEMASK_FREE(node_alloc_noretry
);
2660 /* Fall through to decrease pool */
2664 * Increase the pool size
2665 * First take pages out of surplus state. Then make up the
2666 * remaining difference by allocating fresh huge pages.
2668 * We might race with alloc_surplus_huge_page() here and be unable
2669 * to convert a surplus huge page to a normal huge page. That is
2670 * not critical, though, it just means the overall size of the
2671 * pool might be one hugepage larger than it needs to be, but
2672 * within all the constraints specified by the sysctls.
2674 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2675 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2679 while (count
> persistent_huge_pages(h
)) {
2681 * If this allocation races such that we no longer need the
2682 * page, free_huge_page will handle it by freeing the page
2683 * and reducing the surplus.
2685 spin_unlock(&hugetlb_lock
);
2687 /* yield cpu to avoid soft lockup */
2690 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2691 node_alloc_noretry
);
2692 spin_lock(&hugetlb_lock
);
2696 /* Bail for signals. Probably ctrl-c from user */
2697 if (signal_pending(current
))
2702 * Decrease the pool size
2703 * First return free pages to the buddy allocator (being careful
2704 * to keep enough around to satisfy reservations). Then place
2705 * pages into surplus state as needed so the pool will shrink
2706 * to the desired size as pages become free.
2708 * By placing pages into the surplus state independent of the
2709 * overcommit value, we are allowing the surplus pool size to
2710 * exceed overcommit. There are few sane options here. Since
2711 * alloc_surplus_huge_page() is checking the global counter,
2712 * though, we'll note that we're not allowed to exceed surplus
2713 * and won't grow the pool anywhere else. Not until one of the
2714 * sysctls are changed, or the surplus pages go out of use.
2716 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2717 min_count
= max(count
, min_count
);
2718 try_to_free_low(h
, min_count
, nodes_allowed
);
2719 while (min_count
< persistent_huge_pages(h
)) {
2720 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2722 cond_resched_lock(&hugetlb_lock
);
2724 while (count
< persistent_huge_pages(h
)) {
2725 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2729 h
->max_huge_pages
= persistent_huge_pages(h
);
2730 spin_unlock(&hugetlb_lock
);
2732 NODEMASK_FREE(node_alloc_noretry
);
2737 #define HSTATE_ATTR_RO(_name) \
2738 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2740 #define HSTATE_ATTR(_name) \
2741 static struct kobj_attribute _name##_attr = \
2742 __ATTR(_name, 0644, _name##_show, _name##_store)
2744 static struct kobject
*hugepages_kobj
;
2745 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2747 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2749 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2753 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2754 if (hstate_kobjs
[i
] == kobj
) {
2756 *nidp
= NUMA_NO_NODE
;
2760 return kobj_to_node_hstate(kobj
, nidp
);
2763 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2764 struct kobj_attribute
*attr
, char *buf
)
2767 unsigned long nr_huge_pages
;
2770 h
= kobj_to_hstate(kobj
, &nid
);
2771 if (nid
== NUMA_NO_NODE
)
2772 nr_huge_pages
= h
->nr_huge_pages
;
2774 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2776 return sysfs_emit(buf
, "%lu\n", nr_huge_pages
);
2779 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2780 struct hstate
*h
, int nid
,
2781 unsigned long count
, size_t len
)
2784 nodemask_t nodes_allowed
, *n_mask
;
2786 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2789 if (nid
== NUMA_NO_NODE
) {
2791 * global hstate attribute
2793 if (!(obey_mempolicy
&&
2794 init_nodemask_of_mempolicy(&nodes_allowed
)))
2795 n_mask
= &node_states
[N_MEMORY
];
2797 n_mask
= &nodes_allowed
;
2800 * Node specific request. count adjustment happens in
2801 * set_max_huge_pages() after acquiring hugetlb_lock.
2803 init_nodemask_of_node(&nodes_allowed
, nid
);
2804 n_mask
= &nodes_allowed
;
2807 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2809 return err
? err
: len
;
2812 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2813 struct kobject
*kobj
, const char *buf
,
2817 unsigned long count
;
2821 err
= kstrtoul(buf
, 10, &count
);
2825 h
= kobj_to_hstate(kobj
, &nid
);
2826 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2829 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2830 struct kobj_attribute
*attr
, char *buf
)
2832 return nr_hugepages_show_common(kobj
, attr
, buf
);
2835 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2836 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2838 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2840 HSTATE_ATTR(nr_hugepages
);
2845 * hstate attribute for optionally mempolicy-based constraint on persistent
2846 * huge page alloc/free.
2848 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2849 struct kobj_attribute
*attr
,
2852 return nr_hugepages_show_common(kobj
, attr
, buf
);
2855 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2856 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2858 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2860 HSTATE_ATTR(nr_hugepages_mempolicy
);
2864 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2865 struct kobj_attribute
*attr
, char *buf
)
2867 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2868 return sysfs_emit(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2871 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2872 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2875 unsigned long input
;
2876 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2878 if (hstate_is_gigantic(h
))
2881 err
= kstrtoul(buf
, 10, &input
);
2885 spin_lock(&hugetlb_lock
);
2886 h
->nr_overcommit_huge_pages
= input
;
2887 spin_unlock(&hugetlb_lock
);
2891 HSTATE_ATTR(nr_overcommit_hugepages
);
2893 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2894 struct kobj_attribute
*attr
, char *buf
)
2897 unsigned long free_huge_pages
;
2900 h
= kobj_to_hstate(kobj
, &nid
);
2901 if (nid
== NUMA_NO_NODE
)
2902 free_huge_pages
= h
->free_huge_pages
;
2904 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2906 return sysfs_emit(buf
, "%lu\n", free_huge_pages
);
2908 HSTATE_ATTR_RO(free_hugepages
);
2910 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2911 struct kobj_attribute
*attr
, char *buf
)
2913 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2914 return sysfs_emit(buf
, "%lu\n", h
->resv_huge_pages
);
2916 HSTATE_ATTR_RO(resv_hugepages
);
2918 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2919 struct kobj_attribute
*attr
, char *buf
)
2922 unsigned long surplus_huge_pages
;
2925 h
= kobj_to_hstate(kobj
, &nid
);
2926 if (nid
== NUMA_NO_NODE
)
2927 surplus_huge_pages
= h
->surplus_huge_pages
;
2929 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2931 return sysfs_emit(buf
, "%lu\n", surplus_huge_pages
);
2933 HSTATE_ATTR_RO(surplus_hugepages
);
2935 static struct attribute
*hstate_attrs
[] = {
2936 &nr_hugepages_attr
.attr
,
2937 &nr_overcommit_hugepages_attr
.attr
,
2938 &free_hugepages_attr
.attr
,
2939 &resv_hugepages_attr
.attr
,
2940 &surplus_hugepages_attr
.attr
,
2942 &nr_hugepages_mempolicy_attr
.attr
,
2947 static const struct attribute_group hstate_attr_group
= {
2948 .attrs
= hstate_attrs
,
2951 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2952 struct kobject
**hstate_kobjs
,
2953 const struct attribute_group
*hstate_attr_group
)
2956 int hi
= hstate_index(h
);
2958 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2959 if (!hstate_kobjs
[hi
])
2962 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2964 kobject_put(hstate_kobjs
[hi
]);
2965 hstate_kobjs
[hi
] = NULL
;
2971 static void __init
hugetlb_sysfs_init(void)
2976 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2977 if (!hugepages_kobj
)
2980 for_each_hstate(h
) {
2981 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2982 hstate_kobjs
, &hstate_attr_group
);
2984 pr_err("HugeTLB: Unable to add hstate %s", h
->name
);
2991 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2992 * with node devices in node_devices[] using a parallel array. The array
2993 * index of a node device or _hstate == node id.
2994 * This is here to avoid any static dependency of the node device driver, in
2995 * the base kernel, on the hugetlb module.
2997 struct node_hstate
{
2998 struct kobject
*hugepages_kobj
;
2999 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
3001 static struct node_hstate node_hstates
[MAX_NUMNODES
];
3004 * A subset of global hstate attributes for node devices
3006 static struct attribute
*per_node_hstate_attrs
[] = {
3007 &nr_hugepages_attr
.attr
,
3008 &free_hugepages_attr
.attr
,
3009 &surplus_hugepages_attr
.attr
,
3013 static const struct attribute_group per_node_hstate_attr_group
= {
3014 .attrs
= per_node_hstate_attrs
,
3018 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3019 * Returns node id via non-NULL nidp.
3021 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3025 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
3026 struct node_hstate
*nhs
= &node_hstates
[nid
];
3028 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
3029 if (nhs
->hstate_kobjs
[i
] == kobj
) {
3041 * Unregister hstate attributes from a single node device.
3042 * No-op if no hstate attributes attached.
3044 static void hugetlb_unregister_node(struct node
*node
)
3047 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3049 if (!nhs
->hugepages_kobj
)
3050 return; /* no hstate attributes */
3052 for_each_hstate(h
) {
3053 int idx
= hstate_index(h
);
3054 if (nhs
->hstate_kobjs
[idx
]) {
3055 kobject_put(nhs
->hstate_kobjs
[idx
]);
3056 nhs
->hstate_kobjs
[idx
] = NULL
;
3060 kobject_put(nhs
->hugepages_kobj
);
3061 nhs
->hugepages_kobj
= NULL
;
3066 * Register hstate attributes for a single node device.
3067 * No-op if attributes already registered.
3069 static void hugetlb_register_node(struct node
*node
)
3072 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
3075 if (nhs
->hugepages_kobj
)
3076 return; /* already allocated */
3078 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
3080 if (!nhs
->hugepages_kobj
)
3083 for_each_hstate(h
) {
3084 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
3086 &per_node_hstate_attr_group
);
3088 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3089 h
->name
, node
->dev
.id
);
3090 hugetlb_unregister_node(node
);
3097 * hugetlb init time: register hstate attributes for all registered node
3098 * devices of nodes that have memory. All on-line nodes should have
3099 * registered their associated device by this time.
3101 static void __init
hugetlb_register_all_nodes(void)
3105 for_each_node_state(nid
, N_MEMORY
) {
3106 struct node
*node
= node_devices
[nid
];
3107 if (node
->dev
.id
== nid
)
3108 hugetlb_register_node(node
);
3112 * Let the node device driver know we're here so it can
3113 * [un]register hstate attributes on node hotplug.
3115 register_hugetlbfs_with_node(hugetlb_register_node
,
3116 hugetlb_unregister_node
);
3118 #else /* !CONFIG_NUMA */
3120 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
3128 static void hugetlb_register_all_nodes(void) { }
3132 static int __init
hugetlb_init(void)
3136 BUILD_BUG_ON(sizeof_field(struct page
, private) * BITS_PER_BYTE
<
3139 if (!hugepages_supported()) {
3140 if (hugetlb_max_hstate
|| default_hstate_max_huge_pages
)
3141 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3146 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3147 * architectures depend on setup being done here.
3149 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
3150 if (!parsed_default_hugepagesz
) {
3152 * If we did not parse a default huge page size, set
3153 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3154 * number of huge pages for this default size was implicitly
3155 * specified, set that here as well.
3156 * Note that the implicit setting will overwrite an explicit
3157 * setting. A warning will be printed in this case.
3159 default_hstate_idx
= hstate_index(size_to_hstate(HPAGE_SIZE
));
3160 if (default_hstate_max_huge_pages
) {
3161 if (default_hstate
.max_huge_pages
) {
3164 string_get_size(huge_page_size(&default_hstate
),
3165 1, STRING_UNITS_2
, buf
, 32);
3166 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3167 default_hstate
.max_huge_pages
, buf
);
3168 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3169 default_hstate_max_huge_pages
);
3171 default_hstate
.max_huge_pages
=
3172 default_hstate_max_huge_pages
;
3176 hugetlb_cma_check();
3177 hugetlb_init_hstates();
3178 gather_bootmem_prealloc();
3181 hugetlb_sysfs_init();
3182 hugetlb_register_all_nodes();
3183 hugetlb_cgroup_file_init();
3186 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
3188 num_fault_mutexes
= 1;
3190 hugetlb_fault_mutex_table
=
3191 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
3193 BUG_ON(!hugetlb_fault_mutex_table
);
3195 for (i
= 0; i
< num_fault_mutexes
; i
++)
3196 mutex_init(&hugetlb_fault_mutex_table
[i
]);
3199 subsys_initcall(hugetlb_init
);
3201 /* Overwritten by architectures with more huge page sizes */
3202 bool __init
__attribute((weak
)) arch_hugetlb_valid_size(unsigned long size
)
3204 return size
== HPAGE_SIZE
;
3207 void __init
hugetlb_add_hstate(unsigned int order
)
3212 if (size_to_hstate(PAGE_SIZE
<< order
)) {
3215 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
3217 h
= &hstates
[hugetlb_max_hstate
++];
3219 h
->mask
= ~(huge_page_size(h
) - 1);
3220 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
3221 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
3222 INIT_LIST_HEAD(&h
->hugepage_activelist
);
3223 h
->next_nid_to_alloc
= first_memory_node
;
3224 h
->next_nid_to_free
= first_memory_node
;
3225 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
3226 huge_page_size(h
)/1024);
3232 * hugepages command line processing
3233 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3234 * specification. If not, ignore the hugepages value. hugepages can also
3235 * be the first huge page command line option in which case it implicitly
3236 * specifies the number of huge pages for the default size.
3238 static int __init
hugepages_setup(char *s
)
3241 static unsigned long *last_mhp
;
3243 if (!parsed_valid_hugepagesz
) {
3244 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s
);
3245 parsed_valid_hugepagesz
= true;
3250 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3251 * yet, so this hugepages= parameter goes to the "default hstate".
3252 * Otherwise, it goes with the previously parsed hugepagesz or
3253 * default_hugepagesz.
3255 else if (!hugetlb_max_hstate
)
3256 mhp
= &default_hstate_max_huge_pages
;
3258 mhp
= &parsed_hstate
->max_huge_pages
;
3260 if (mhp
== last_mhp
) {
3261 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s
);
3265 if (sscanf(s
, "%lu", mhp
) <= 0)
3269 * Global state is always initialized later in hugetlb_init.
3270 * But we need to allocate >= MAX_ORDER hstates here early to still
3271 * use the bootmem allocator.
3273 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
3274 hugetlb_hstate_alloc_pages(parsed_hstate
);
3280 __setup("hugepages=", hugepages_setup
);
3283 * hugepagesz command line processing
3284 * A specific huge page size can only be specified once with hugepagesz.
3285 * hugepagesz is followed by hugepages on the command line. The global
3286 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3287 * hugepagesz argument was valid.
3289 static int __init
hugepagesz_setup(char *s
)
3294 parsed_valid_hugepagesz
= false;
3295 size
= (unsigned long)memparse(s
, NULL
);
3297 if (!arch_hugetlb_valid_size(size
)) {
3298 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s
);
3302 h
= size_to_hstate(size
);
3305 * hstate for this size already exists. This is normally
3306 * an error, but is allowed if the existing hstate is the
3307 * default hstate. More specifically, it is only allowed if
3308 * the number of huge pages for the default hstate was not
3309 * previously specified.
3311 if (!parsed_default_hugepagesz
|| h
!= &default_hstate
||
3312 default_hstate
.max_huge_pages
) {
3313 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s
);
3318 * No need to call hugetlb_add_hstate() as hstate already
3319 * exists. But, do set parsed_hstate so that a following
3320 * hugepages= parameter will be applied to this hstate.
3323 parsed_valid_hugepagesz
= true;
3327 hugetlb_add_hstate(ilog2(size
) - PAGE_SHIFT
);
3328 parsed_valid_hugepagesz
= true;
3331 __setup("hugepagesz=", hugepagesz_setup
);
3334 * default_hugepagesz command line input
3335 * Only one instance of default_hugepagesz allowed on command line.
3337 static int __init
default_hugepagesz_setup(char *s
)
3341 parsed_valid_hugepagesz
= false;
3342 if (parsed_default_hugepagesz
) {
3343 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s
);
3347 size
= (unsigned long)memparse(s
, NULL
);
3349 if (!arch_hugetlb_valid_size(size
)) {
3350 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s
);
3354 hugetlb_add_hstate(ilog2(size
) - PAGE_SHIFT
);
3355 parsed_valid_hugepagesz
= true;
3356 parsed_default_hugepagesz
= true;
3357 default_hstate_idx
= hstate_index(size_to_hstate(size
));
3360 * The number of default huge pages (for this size) could have been
3361 * specified as the first hugetlb parameter: hugepages=X. If so,
3362 * then default_hstate_max_huge_pages is set. If the default huge
3363 * page size is gigantic (>= MAX_ORDER), then the pages must be
3364 * allocated here from bootmem allocator.
3366 if (default_hstate_max_huge_pages
) {
3367 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
3368 if (hstate_is_gigantic(&default_hstate
))
3369 hugetlb_hstate_alloc_pages(&default_hstate
);
3370 default_hstate_max_huge_pages
= 0;
3375 __setup("default_hugepagesz=", default_hugepagesz_setup
);
3377 static unsigned int allowed_mems_nr(struct hstate
*h
)
3380 unsigned int nr
= 0;
3381 nodemask_t
*mpol_allowed
;
3382 unsigned int *array
= h
->free_huge_pages_node
;
3383 gfp_t gfp_mask
= htlb_alloc_mask(h
);
3385 mpol_allowed
= policy_nodemask_current(gfp_mask
);
3387 for_each_node_mask(node
, cpuset_current_mems_allowed
) {
3388 if (!mpol_allowed
|| node_isset(node
, *mpol_allowed
))
3395 #ifdef CONFIG_SYSCTL
3396 static int proc_hugetlb_doulongvec_minmax(struct ctl_table
*table
, int write
,
3397 void *buffer
, size_t *length
,
3398 loff_t
*ppos
, unsigned long *out
)
3400 struct ctl_table dup_table
;
3403 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3404 * can duplicate the @table and alter the duplicate of it.
3407 dup_table
.data
= out
;
3409 return proc_doulongvec_minmax(&dup_table
, write
, buffer
, length
, ppos
);
3412 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
3413 struct ctl_table
*table
, int write
,
3414 void *buffer
, size_t *length
, loff_t
*ppos
)
3416 struct hstate
*h
= &default_hstate
;
3417 unsigned long tmp
= h
->max_huge_pages
;
3420 if (!hugepages_supported())
3423 ret
= proc_hugetlb_doulongvec_minmax(table
, write
, buffer
, length
, ppos
,
3429 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
3430 NUMA_NO_NODE
, tmp
, *length
);
3435 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
3436 void *buffer
, size_t *length
, loff_t
*ppos
)
3439 return hugetlb_sysctl_handler_common(false, table
, write
,
3440 buffer
, length
, ppos
);
3444 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3445 void *buffer
, size_t *length
, loff_t
*ppos
)
3447 return hugetlb_sysctl_handler_common(true, table
, write
,
3448 buffer
, length
, ppos
);
3450 #endif /* CONFIG_NUMA */
3452 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3453 void *buffer
, size_t *length
, loff_t
*ppos
)
3455 struct hstate
*h
= &default_hstate
;
3459 if (!hugepages_supported())
3462 tmp
= h
->nr_overcommit_huge_pages
;
3464 if (write
&& hstate_is_gigantic(h
))
3467 ret
= proc_hugetlb_doulongvec_minmax(table
, write
, buffer
, length
, ppos
,
3473 spin_lock(&hugetlb_lock
);
3474 h
->nr_overcommit_huge_pages
= tmp
;
3475 spin_unlock(&hugetlb_lock
);
3481 #endif /* CONFIG_SYSCTL */
3483 void hugetlb_report_meminfo(struct seq_file
*m
)
3486 unsigned long total
= 0;
3488 if (!hugepages_supported())
3491 for_each_hstate(h
) {
3492 unsigned long count
= h
->nr_huge_pages
;
3494 total
+= huge_page_size(h
) * count
;
3496 if (h
== &default_hstate
)
3498 "HugePages_Total: %5lu\n"
3499 "HugePages_Free: %5lu\n"
3500 "HugePages_Rsvd: %5lu\n"
3501 "HugePages_Surp: %5lu\n"
3502 "Hugepagesize: %8lu kB\n",
3506 h
->surplus_huge_pages
,
3507 huge_page_size(h
) / SZ_1K
);
3510 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ SZ_1K
);
3513 int hugetlb_report_node_meminfo(char *buf
, int len
, int nid
)
3515 struct hstate
*h
= &default_hstate
;
3517 if (!hugepages_supported())
3520 return sysfs_emit_at(buf
, len
,
3521 "Node %d HugePages_Total: %5u\n"
3522 "Node %d HugePages_Free: %5u\n"
3523 "Node %d HugePages_Surp: %5u\n",
3524 nid
, h
->nr_huge_pages_node
[nid
],
3525 nid
, h
->free_huge_pages_node
[nid
],
3526 nid
, h
->surplus_huge_pages_node
[nid
]);
3529 void hugetlb_show_meminfo(void)
3534 if (!hugepages_supported())
3537 for_each_node_state(nid
, N_MEMORY
)
3539 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3541 h
->nr_huge_pages_node
[nid
],
3542 h
->free_huge_pages_node
[nid
],
3543 h
->surplus_huge_pages_node
[nid
],
3544 huge_page_size(h
) / SZ_1K
);
3547 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3549 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3550 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3553 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3554 unsigned long hugetlb_total_pages(void)
3557 unsigned long nr_total_pages
= 0;
3560 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3561 return nr_total_pages
;
3564 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3571 spin_lock(&hugetlb_lock
);
3573 * When cpuset is configured, it breaks the strict hugetlb page
3574 * reservation as the accounting is done on a global variable. Such
3575 * reservation is completely rubbish in the presence of cpuset because
3576 * the reservation is not checked against page availability for the
3577 * current cpuset. Application can still potentially OOM'ed by kernel
3578 * with lack of free htlb page in cpuset that the task is in.
3579 * Attempt to enforce strict accounting with cpuset is almost
3580 * impossible (or too ugly) because cpuset is too fluid that
3581 * task or memory node can be dynamically moved between cpusets.
3583 * The change of semantics for shared hugetlb mapping with cpuset is
3584 * undesirable. However, in order to preserve some of the semantics,
3585 * we fall back to check against current free page availability as
3586 * a best attempt and hopefully to minimize the impact of changing
3587 * semantics that cpuset has.
3589 * Apart from cpuset, we also have memory policy mechanism that
3590 * also determines from which node the kernel will allocate memory
3591 * in a NUMA system. So similar to cpuset, we also should consider
3592 * the memory policy of the current task. Similar to the description
3596 if (gather_surplus_pages(h
, delta
) < 0)
3599 if (delta
> allowed_mems_nr(h
)) {
3600 return_unused_surplus_pages(h
, delta
);
3607 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3610 spin_unlock(&hugetlb_lock
);
3614 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3616 struct resv_map
*resv
= vma_resv_map(vma
);
3619 * This new VMA should share its siblings reservation map if present.
3620 * The VMA will only ever have a valid reservation map pointer where
3621 * it is being copied for another still existing VMA. As that VMA
3622 * has a reference to the reservation map it cannot disappear until
3623 * after this open call completes. It is therefore safe to take a
3624 * new reference here without additional locking.
3626 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3627 kref_get(&resv
->refs
);
3630 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3632 struct hstate
*h
= hstate_vma(vma
);
3633 struct resv_map
*resv
= vma_resv_map(vma
);
3634 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3635 unsigned long reserve
, start
, end
;
3638 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3641 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3642 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3644 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3645 hugetlb_cgroup_uncharge_counter(resv
, start
, end
);
3648 * Decrement reserve counts. The global reserve count may be
3649 * adjusted if the subpool has a minimum size.
3651 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3652 hugetlb_acct_memory(h
, -gbl_reserve
);
3655 kref_put(&resv
->refs
, resv_map_release
);
3658 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3660 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3665 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3667 return huge_page_size(hstate_vma(vma
));
3671 * We cannot handle pagefaults against hugetlb pages at all. They cause
3672 * handle_mm_fault() to try to instantiate regular-sized pages in the
3673 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3676 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3683 * When a new function is introduced to vm_operations_struct and added
3684 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3685 * This is because under System V memory model, mappings created via
3686 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3687 * their original vm_ops are overwritten with shm_vm_ops.
3689 const struct vm_operations_struct hugetlb_vm_ops
= {
3690 .fault
= hugetlb_vm_op_fault
,
3691 .open
= hugetlb_vm_op_open
,
3692 .close
= hugetlb_vm_op_close
,
3693 .may_split
= hugetlb_vm_op_split
,
3694 .pagesize
= hugetlb_vm_op_pagesize
,
3697 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3703 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3704 vma
->vm_page_prot
)));
3706 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3707 vma
->vm_page_prot
));
3709 entry
= pte_mkyoung(entry
);
3710 entry
= pte_mkhuge(entry
);
3711 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3716 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3717 unsigned long address
, pte_t
*ptep
)
3721 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3722 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3723 update_mmu_cache(vma
, address
, ptep
);
3726 bool is_hugetlb_entry_migration(pte_t pte
)
3730 if (huge_pte_none(pte
) || pte_present(pte
))
3732 swp
= pte_to_swp_entry(pte
);
3733 if (is_migration_entry(swp
))
3739 static bool is_hugetlb_entry_hwpoisoned(pte_t pte
)
3743 if (huge_pte_none(pte
) || pte_present(pte
))
3745 swp
= pte_to_swp_entry(pte
);
3746 if (is_hwpoison_entry(swp
))
3753 hugetlb_install_page(struct vm_area_struct
*vma
, pte_t
*ptep
, unsigned long addr
,
3754 struct page
*new_page
)
3756 __SetPageUptodate(new_page
);
3757 set_huge_pte_at(vma
->vm_mm
, addr
, ptep
, make_huge_pte(vma
, new_page
, 1));
3758 hugepage_add_new_anon_rmap(new_page
, vma
, addr
);
3759 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma
)), vma
->vm_mm
);
3760 ClearHPageRestoreReserve(new_page
);
3761 SetHPageMigratable(new_page
);
3764 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3765 struct vm_area_struct
*vma
)
3767 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3768 struct page
*ptepage
;
3770 bool cow
= is_cow_mapping(vma
->vm_flags
);
3771 struct hstate
*h
= hstate_vma(vma
);
3772 unsigned long sz
= huge_page_size(h
);
3773 unsigned long npages
= pages_per_huge_page(h
);
3774 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
3775 struct mmu_notifier_range range
;
3779 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3782 mmu_notifier_invalidate_range_start(&range
);
3785 * For shared mappings i_mmap_rwsem must be held to call
3786 * huge_pte_alloc, otherwise the returned ptep could go
3787 * away if part of a shared pmd and another thread calls
3790 i_mmap_lock_read(mapping
);
3793 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3794 spinlock_t
*src_ptl
, *dst_ptl
;
3795 src_pte
= huge_pte_offset(src
, addr
, sz
);
3798 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3805 * If the pagetables are shared don't copy or take references.
3806 * dst_pte == src_pte is the common case of src/dest sharing.
3808 * However, src could have 'unshared' and dst shares with
3809 * another vma. If dst_pte !none, this implies sharing.
3810 * Check here before taking page table lock, and once again
3811 * after taking the lock below.
3813 dst_entry
= huge_ptep_get(dst_pte
);
3814 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3817 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3818 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3819 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3820 entry
= huge_ptep_get(src_pte
);
3821 dst_entry
= huge_ptep_get(dst_pte
);
3823 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3825 * Skip if src entry none. Also, skip in the
3826 * unlikely case dst entry !none as this implies
3827 * sharing with another vma.
3830 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3831 is_hugetlb_entry_hwpoisoned(entry
))) {
3832 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3834 if (is_write_migration_entry(swp_entry
) && cow
) {
3836 * COW mappings require pages in both
3837 * parent and child to be set to read.
3839 make_migration_entry_read(&swp_entry
);
3840 entry
= swp_entry_to_pte(swp_entry
);
3841 set_huge_swap_pte_at(src
, addr
, src_pte
,
3844 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3846 entry
= huge_ptep_get(src_pte
);
3847 ptepage
= pte_page(entry
);
3851 * This is a rare case where we see pinned hugetlb
3852 * pages while they're prone to COW. We need to do the
3853 * COW earlier during fork.
3855 * When pre-allocating the page or copying data, we
3856 * need to be without the pgtable locks since we could
3857 * sleep during the process.
3859 if (unlikely(page_needs_cow_for_dma(vma
, ptepage
))) {
3860 pte_t src_pte_old
= entry
;
3863 spin_unlock(src_ptl
);
3864 spin_unlock(dst_ptl
);
3865 /* Do not use reserve as it's private owned */
3866 new = alloc_huge_page(vma
, addr
, 1);
3872 copy_user_huge_page(new, ptepage
, addr
, vma
,
3876 /* Install the new huge page if src pte stable */
3877 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3878 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3879 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3880 entry
= huge_ptep_get(src_pte
);
3881 if (!pte_same(src_pte_old
, entry
)) {
3883 /* dst_entry won't change as in child */
3886 hugetlb_install_page(vma
, dst_pte
, addr
, new);
3887 spin_unlock(src_ptl
);
3888 spin_unlock(dst_ptl
);
3894 * No need to notify as we are downgrading page
3895 * table protection not changing it to point
3898 * See Documentation/vm/mmu_notifier.rst
3900 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3903 page_dup_rmap(ptepage
, true);
3904 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3905 hugetlb_count_add(npages
, dst
);
3907 spin_unlock(src_ptl
);
3908 spin_unlock(dst_ptl
);
3912 mmu_notifier_invalidate_range_end(&range
);
3914 i_mmap_unlock_read(mapping
);
3919 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3920 unsigned long start
, unsigned long end
,
3921 struct page
*ref_page
)
3923 struct mm_struct
*mm
= vma
->vm_mm
;
3924 unsigned long address
;
3929 struct hstate
*h
= hstate_vma(vma
);
3930 unsigned long sz
= huge_page_size(h
);
3931 struct mmu_notifier_range range
;
3933 WARN_ON(!is_vm_hugetlb_page(vma
));
3934 BUG_ON(start
& ~huge_page_mask(h
));
3935 BUG_ON(end
& ~huge_page_mask(h
));
3938 * This is a hugetlb vma, all the pte entries should point
3941 tlb_change_page_size(tlb
, sz
);
3942 tlb_start_vma(tlb
, vma
);
3945 * If sharing possible, alert mmu notifiers of worst case.
3947 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3949 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3950 mmu_notifier_invalidate_range_start(&range
);
3952 for (; address
< end
; address
+= sz
) {
3953 ptep
= huge_pte_offset(mm
, address
, sz
);
3957 ptl
= huge_pte_lock(h
, mm
, ptep
);
3958 if (huge_pmd_unshare(mm
, vma
, &address
, ptep
)) {
3961 * We just unmapped a page of PMDs by clearing a PUD.
3962 * The caller's TLB flush range should cover this area.
3967 pte
= huge_ptep_get(ptep
);
3968 if (huge_pte_none(pte
)) {
3974 * Migrating hugepage or HWPoisoned hugepage is already
3975 * unmapped and its refcount is dropped, so just clear pte here.
3977 if (unlikely(!pte_present(pte
))) {
3978 huge_pte_clear(mm
, address
, ptep
, sz
);
3983 page
= pte_page(pte
);
3985 * If a reference page is supplied, it is because a specific
3986 * page is being unmapped, not a range. Ensure the page we
3987 * are about to unmap is the actual page of interest.
3990 if (page
!= ref_page
) {
3995 * Mark the VMA as having unmapped its page so that
3996 * future faults in this VMA will fail rather than
3997 * looking like data was lost
3999 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
4002 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
4003 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
4004 if (huge_pte_dirty(pte
))
4005 set_page_dirty(page
);
4007 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
4008 page_remove_rmap(page
, true);
4011 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
4013 * Bail out after unmapping reference page if supplied
4018 mmu_notifier_invalidate_range_end(&range
);
4019 tlb_end_vma(tlb
, vma
);
4022 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
4023 struct vm_area_struct
*vma
, unsigned long start
,
4024 unsigned long end
, struct page
*ref_page
)
4026 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
4029 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4030 * test will fail on a vma being torn down, and not grab a page table
4031 * on its way out. We're lucky that the flag has such an appropriate
4032 * name, and can in fact be safely cleared here. We could clear it
4033 * before the __unmap_hugepage_range above, but all that's necessary
4034 * is to clear it before releasing the i_mmap_rwsem. This works
4035 * because in the context this is called, the VMA is about to be
4036 * destroyed and the i_mmap_rwsem is held.
4038 vma
->vm_flags
&= ~VM_MAYSHARE
;
4041 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
4042 unsigned long end
, struct page
*ref_page
)
4044 struct mmu_gather tlb
;
4046 tlb_gather_mmu(&tlb
, vma
->vm_mm
);
4047 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
4048 tlb_finish_mmu(&tlb
);
4052 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4053 * mapping it owns the reserve page for. The intention is to unmap the page
4054 * from other VMAs and let the children be SIGKILLed if they are faulting the
4057 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4058 struct page
*page
, unsigned long address
)
4060 struct hstate
*h
= hstate_vma(vma
);
4061 struct vm_area_struct
*iter_vma
;
4062 struct address_space
*mapping
;
4066 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4067 * from page cache lookup which is in HPAGE_SIZE units.
4069 address
= address
& huge_page_mask(h
);
4070 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
4072 mapping
= vma
->vm_file
->f_mapping
;
4075 * Take the mapping lock for the duration of the table walk. As
4076 * this mapping should be shared between all the VMAs,
4077 * __unmap_hugepage_range() is called as the lock is already held
4079 i_mmap_lock_write(mapping
);
4080 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
4081 /* Do not unmap the current VMA */
4082 if (iter_vma
== vma
)
4086 * Shared VMAs have their own reserves and do not affect
4087 * MAP_PRIVATE accounting but it is possible that a shared
4088 * VMA is using the same page so check and skip such VMAs.
4090 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
4094 * Unmap the page from other VMAs without their own reserves.
4095 * They get marked to be SIGKILLed if they fault in these
4096 * areas. This is because a future no-page fault on this VMA
4097 * could insert a zeroed page instead of the data existing
4098 * from the time of fork. This would look like data corruption
4100 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
4101 unmap_hugepage_range(iter_vma
, address
,
4102 address
+ huge_page_size(h
), page
);
4104 i_mmap_unlock_write(mapping
);
4108 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4109 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4110 * cannot race with other handlers or page migration.
4111 * Keep the pte_same checks anyway to make transition from the mutex easier.
4113 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4114 unsigned long address
, pte_t
*ptep
,
4115 struct page
*pagecache_page
, spinlock_t
*ptl
)
4118 struct hstate
*h
= hstate_vma(vma
);
4119 struct page
*old_page
, *new_page
;
4120 int outside_reserve
= 0;
4122 unsigned long haddr
= address
& huge_page_mask(h
);
4123 struct mmu_notifier_range range
;
4125 pte
= huge_ptep_get(ptep
);
4126 old_page
= pte_page(pte
);
4129 /* If no-one else is actually using this page, avoid the copy
4130 * and just make the page writable */
4131 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
4132 page_move_anon_rmap(old_page
, vma
);
4133 set_huge_ptep_writable(vma
, haddr
, ptep
);
4138 * If the process that created a MAP_PRIVATE mapping is about to
4139 * perform a COW due to a shared page count, attempt to satisfy
4140 * the allocation without using the existing reserves. The pagecache
4141 * page is used to determine if the reserve at this address was
4142 * consumed or not. If reserves were used, a partial faulted mapping
4143 * at the time of fork() could consume its reserves on COW instead
4144 * of the full address range.
4146 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
4147 old_page
!= pagecache_page
)
4148 outside_reserve
= 1;
4153 * Drop page table lock as buddy allocator may be called. It will
4154 * be acquired again before returning to the caller, as expected.
4157 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
4159 if (IS_ERR(new_page
)) {
4161 * If a process owning a MAP_PRIVATE mapping fails to COW,
4162 * it is due to references held by a child and an insufficient
4163 * huge page pool. To guarantee the original mappers
4164 * reliability, unmap the page from child processes. The child
4165 * may get SIGKILLed if it later faults.
4167 if (outside_reserve
) {
4168 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4173 BUG_ON(huge_pte_none(pte
));
4175 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4176 * unmapping. unmapping needs to hold i_mmap_rwsem
4177 * in write mode. Dropping i_mmap_rwsem in read mode
4178 * here is OK as COW mappings do not interact with
4181 * Reacquire both after unmap operation.
4183 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4184 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4185 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4186 i_mmap_unlock_read(mapping
);
4188 unmap_ref_private(mm
, vma
, old_page
, haddr
);
4190 i_mmap_lock_read(mapping
);
4191 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4193 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4195 pte_same(huge_ptep_get(ptep
), pte
)))
4196 goto retry_avoidcopy
;
4198 * race occurs while re-acquiring page table
4199 * lock, and our job is done.
4204 ret
= vmf_error(PTR_ERR(new_page
));
4205 goto out_release_old
;
4209 * When the original hugepage is shared one, it does not have
4210 * anon_vma prepared.
4212 if (unlikely(anon_vma_prepare(vma
))) {
4214 goto out_release_all
;
4217 copy_user_huge_page(new_page
, old_page
, address
, vma
,
4218 pages_per_huge_page(h
));
4219 __SetPageUptodate(new_page
);
4221 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
4222 haddr
+ huge_page_size(h
));
4223 mmu_notifier_invalidate_range_start(&range
);
4226 * Retake the page table lock to check for racing updates
4227 * before the page tables are altered
4230 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4231 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
4232 ClearHPageRestoreReserve(new_page
);
4235 huge_ptep_clear_flush(vma
, haddr
, ptep
);
4236 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
4237 set_huge_pte_at(mm
, haddr
, ptep
,
4238 make_huge_pte(vma
, new_page
, 1));
4239 page_remove_rmap(old_page
, true);
4240 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
4241 SetHPageMigratable(new_page
);
4242 /* Make the old page be freed below */
4243 new_page
= old_page
;
4246 mmu_notifier_invalidate_range_end(&range
);
4248 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
4253 spin_lock(ptl
); /* Caller expects lock to be held */
4257 /* Return the pagecache page at a given address within a VMA */
4258 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
4259 struct vm_area_struct
*vma
, unsigned long address
)
4261 struct address_space
*mapping
;
4264 mapping
= vma
->vm_file
->f_mapping
;
4265 idx
= vma_hugecache_offset(h
, vma
, address
);
4267 return find_lock_page(mapping
, idx
);
4271 * Return whether there is a pagecache page to back given address within VMA.
4272 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4274 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
4275 struct vm_area_struct
*vma
, unsigned long address
)
4277 struct address_space
*mapping
;
4281 mapping
= vma
->vm_file
->f_mapping
;
4282 idx
= vma_hugecache_offset(h
, vma
, address
);
4284 page
= find_get_page(mapping
, idx
);
4287 return page
!= NULL
;
4290 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
4293 struct inode
*inode
= mapping
->host
;
4294 struct hstate
*h
= hstate_inode(inode
);
4295 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
4299 ClearHPageRestoreReserve(page
);
4302 * set page dirty so that it will not be removed from cache/file
4303 * by non-hugetlbfs specific code paths.
4305 set_page_dirty(page
);
4307 spin_lock(&inode
->i_lock
);
4308 inode
->i_blocks
+= blocks_per_huge_page(h
);
4309 spin_unlock(&inode
->i_lock
);
4313 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
4314 struct vm_area_struct
*vma
,
4315 struct address_space
*mapping
, pgoff_t idx
,
4316 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
4318 struct hstate
*h
= hstate_vma(vma
);
4319 vm_fault_t ret
= VM_FAULT_SIGBUS
;
4325 unsigned long haddr
= address
& huge_page_mask(h
);
4326 bool new_page
= false;
4329 * Currently, we are forced to kill the process in the event the
4330 * original mapper has unmapped pages from the child due to a failed
4331 * COW. Warn that such a situation has occurred as it may not be obvious
4333 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
4334 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4340 * We can not race with truncation due to holding i_mmap_rwsem.
4341 * i_size is modified when holding i_mmap_rwsem, so check here
4342 * once for faults beyond end of file.
4344 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4349 page
= find_lock_page(mapping
, idx
);
4352 * Check for page in userfault range
4354 if (userfaultfd_missing(vma
)) {
4356 struct vm_fault vmf
= {
4361 * Hard to debug if it ends up being
4362 * used by a callee that assumes
4363 * something about the other
4364 * uninitialized fields... same as in
4370 * hugetlb_fault_mutex and i_mmap_rwsem must be
4371 * dropped before handling userfault. Reacquire
4372 * after handling fault to make calling code simpler.
4374 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4375 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4376 i_mmap_unlock_read(mapping
);
4377 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
4378 i_mmap_lock_read(mapping
);
4379 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4383 page
= alloc_huge_page(vma
, haddr
, 0);
4386 * Returning error will result in faulting task being
4387 * sent SIGBUS. The hugetlb fault mutex prevents two
4388 * tasks from racing to fault in the same page which
4389 * could result in false unable to allocate errors.
4390 * Page migration does not take the fault mutex, but
4391 * does a clear then write of pte's under page table
4392 * lock. Page fault code could race with migration,
4393 * notice the clear pte and try to allocate a page
4394 * here. Before returning error, get ptl and make
4395 * sure there really is no pte entry.
4397 ptl
= huge_pte_lock(h
, mm
, ptep
);
4398 if (!huge_pte_none(huge_ptep_get(ptep
))) {
4404 ret
= vmf_error(PTR_ERR(page
));
4407 clear_huge_page(page
, address
, pages_per_huge_page(h
));
4408 __SetPageUptodate(page
);
4411 if (vma
->vm_flags
& VM_MAYSHARE
) {
4412 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
4421 if (unlikely(anon_vma_prepare(vma
))) {
4423 goto backout_unlocked
;
4429 * If memory error occurs between mmap() and fault, some process
4430 * don't have hwpoisoned swap entry for errored virtual address.
4431 * So we need to block hugepage fault by PG_hwpoison bit check.
4433 if (unlikely(PageHWPoison(page
))) {
4434 ret
= VM_FAULT_HWPOISON_LARGE
|
4435 VM_FAULT_SET_HINDEX(hstate_index(h
));
4436 goto backout_unlocked
;
4441 * If we are going to COW a private mapping later, we examine the
4442 * pending reservations for this page now. This will ensure that
4443 * any allocations necessary to record that reservation occur outside
4446 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4447 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4449 goto backout_unlocked
;
4451 /* Just decrements count, does not deallocate */
4452 vma_end_reservation(h
, vma
, haddr
);
4455 ptl
= huge_pte_lock(h
, mm
, ptep
);
4457 if (!huge_pte_none(huge_ptep_get(ptep
)))
4461 ClearHPageRestoreReserve(page
);
4462 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
4464 page_dup_rmap(page
, true);
4465 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
4466 && (vma
->vm_flags
& VM_SHARED
)));
4467 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
4469 hugetlb_count_add(pages_per_huge_page(h
), mm
);
4470 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4471 /* Optimization, do the COW without a second fault */
4472 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
4478 * Only set HPageMigratable in newly allocated pages. Existing pages
4479 * found in the pagecache may not have HPageMigratableset if they have
4480 * been isolated for migration.
4483 SetHPageMigratable(page
);
4493 restore_reserve_on_error(h
, vma
, haddr
, page
);
4499 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4501 unsigned long key
[2];
4504 key
[0] = (unsigned long) mapping
;
4507 hash
= jhash2((u32
*)&key
, sizeof(key
)/(sizeof(u32
)), 0);
4509 return hash
& (num_fault_mutexes
- 1);
4513 * For uniprocessor systems we always use a single mutex, so just
4514 * return 0 and avoid the hashing overhead.
4516 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4522 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4523 unsigned long address
, unsigned int flags
)
4530 struct page
*page
= NULL
;
4531 struct page
*pagecache_page
= NULL
;
4532 struct hstate
*h
= hstate_vma(vma
);
4533 struct address_space
*mapping
;
4534 int need_wait_lock
= 0;
4535 unsigned long haddr
= address
& huge_page_mask(h
);
4537 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4540 * Since we hold no locks, ptep could be stale. That is
4541 * OK as we are only making decisions based on content and
4542 * not actually modifying content here.
4544 entry
= huge_ptep_get(ptep
);
4545 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4546 migration_entry_wait_huge(vma
, mm
, ptep
);
4548 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4549 return VM_FAULT_HWPOISON_LARGE
|
4550 VM_FAULT_SET_HINDEX(hstate_index(h
));
4554 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4555 * until finished with ptep. This serves two purposes:
4556 * 1) It prevents huge_pmd_unshare from being called elsewhere
4557 * and making the ptep no longer valid.
4558 * 2) It synchronizes us with i_size modifications during truncation.
4560 * ptep could have already be assigned via huge_pte_offset. That
4561 * is OK, as huge_pte_alloc will return the same value unless
4562 * something has changed.
4564 mapping
= vma
->vm_file
->f_mapping
;
4565 i_mmap_lock_read(mapping
);
4566 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4568 i_mmap_unlock_read(mapping
);
4569 return VM_FAULT_OOM
;
4573 * Serialize hugepage allocation and instantiation, so that we don't
4574 * get spurious allocation failures if two CPUs race to instantiate
4575 * the same page in the page cache.
4577 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4578 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4579 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4581 entry
= huge_ptep_get(ptep
);
4582 if (huge_pte_none(entry
)) {
4583 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4590 * entry could be a migration/hwpoison entry at this point, so this
4591 * check prevents the kernel from going below assuming that we have
4592 * an active hugepage in pagecache. This goto expects the 2nd page
4593 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4594 * properly handle it.
4596 if (!pte_present(entry
))
4600 * If we are going to COW the mapping later, we examine the pending
4601 * reservations for this page now. This will ensure that any
4602 * allocations necessary to record that reservation occur outside the
4603 * spinlock. For private mappings, we also lookup the pagecache
4604 * page now as it is used to determine if a reservation has been
4607 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4608 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4612 /* Just decrements count, does not deallocate */
4613 vma_end_reservation(h
, vma
, haddr
);
4615 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4616 pagecache_page
= hugetlbfs_pagecache_page(h
,
4620 ptl
= huge_pte_lock(h
, mm
, ptep
);
4622 /* Check for a racing update before calling hugetlb_cow */
4623 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4627 * hugetlb_cow() requires page locks of pte_page(entry) and
4628 * pagecache_page, so here we need take the former one
4629 * when page != pagecache_page or !pagecache_page.
4631 page
= pte_page(entry
);
4632 if (page
!= pagecache_page
)
4633 if (!trylock_page(page
)) {
4640 if (flags
& FAULT_FLAG_WRITE
) {
4641 if (!huge_pte_write(entry
)) {
4642 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4643 pagecache_page
, ptl
);
4646 entry
= huge_pte_mkdirty(entry
);
4648 entry
= pte_mkyoung(entry
);
4649 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4650 flags
& FAULT_FLAG_WRITE
))
4651 update_mmu_cache(vma
, haddr
, ptep
);
4653 if (page
!= pagecache_page
)
4659 if (pagecache_page
) {
4660 unlock_page(pagecache_page
);
4661 put_page(pagecache_page
);
4664 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4665 i_mmap_unlock_read(mapping
);
4667 * Generally it's safe to hold refcount during waiting page lock. But
4668 * here we just wait to defer the next page fault to avoid busy loop and
4669 * the page is not used after unlocked before returning from the current
4670 * page fault. So we are safe from accessing freed page, even if we wait
4671 * here without taking refcount.
4674 wait_on_page_locked(page
);
4679 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4680 * modifications for huge pages.
4682 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4684 struct vm_area_struct
*dst_vma
,
4685 unsigned long dst_addr
,
4686 unsigned long src_addr
,
4687 struct page
**pagep
)
4689 struct address_space
*mapping
;
4692 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4693 struct hstate
*h
= hstate_vma(dst_vma
);
4701 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4705 ret
= copy_huge_page_from_user(page
,
4706 (const void __user
*) src_addr
,
4707 pages_per_huge_page(h
), false);
4709 /* fallback to copy_from_user outside mmap_lock */
4710 if (unlikely(ret
)) {
4713 /* don't free the page */
4722 * The memory barrier inside __SetPageUptodate makes sure that
4723 * preceding stores to the page contents become visible before
4724 * the set_pte_at() write.
4726 __SetPageUptodate(page
);
4728 mapping
= dst_vma
->vm_file
->f_mapping
;
4729 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4732 * If shared, add to page cache
4735 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4738 goto out_release_nounlock
;
4741 * Serialization between remove_inode_hugepages() and
4742 * huge_add_to_page_cache() below happens through the
4743 * hugetlb_fault_mutex_table that here must be hold by
4746 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4748 goto out_release_nounlock
;
4751 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4755 * Recheck the i_size after holding PT lock to make sure not
4756 * to leave any page mapped (as page_mapped()) beyond the end
4757 * of the i_size (remove_inode_hugepages() is strict about
4758 * enforcing that). If we bail out here, we'll also leave a
4759 * page in the radix tree in the vm_shared case beyond the end
4760 * of the i_size, but remove_inode_hugepages() will take care
4761 * of it as soon as we drop the hugetlb_fault_mutex_table.
4763 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4766 goto out_release_unlock
;
4769 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4770 goto out_release_unlock
;
4773 page_dup_rmap(page
, true);
4775 ClearHPageRestoreReserve(page
);
4776 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4779 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4780 if (dst_vma
->vm_flags
& VM_WRITE
)
4781 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4782 _dst_pte
= pte_mkyoung(_dst_pte
);
4784 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4786 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4787 dst_vma
->vm_flags
& VM_WRITE
);
4788 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4790 /* No need to invalidate - it was non-present before */
4791 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4794 SetHPageMigratable(page
);
4804 out_release_nounlock
:
4809 static void record_subpages_vmas(struct page
*page
, struct vm_area_struct
*vma
,
4810 int refs
, struct page
**pages
,
4811 struct vm_area_struct
**vmas
)
4815 for (nr
= 0; nr
< refs
; nr
++) {
4817 pages
[nr
] = mem_map_offset(page
, nr
);
4823 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4824 struct page
**pages
, struct vm_area_struct
**vmas
,
4825 unsigned long *position
, unsigned long *nr_pages
,
4826 long i
, unsigned int flags
, int *locked
)
4828 unsigned long pfn_offset
;
4829 unsigned long vaddr
= *position
;
4830 unsigned long remainder
= *nr_pages
;
4831 struct hstate
*h
= hstate_vma(vma
);
4832 int err
= -EFAULT
, refs
;
4834 while (vaddr
< vma
->vm_end
&& remainder
) {
4836 spinlock_t
*ptl
= NULL
;
4841 * If we have a pending SIGKILL, don't keep faulting pages and
4842 * potentially allocating memory.
4844 if (fatal_signal_pending(current
)) {
4850 * Some archs (sparc64, sh*) have multiple pte_ts to
4851 * each hugepage. We have to make sure we get the
4852 * first, for the page indexing below to work.
4854 * Note that page table lock is not held when pte is null.
4856 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4859 ptl
= huge_pte_lock(h
, mm
, pte
);
4860 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4863 * When coredumping, it suits get_dump_page if we just return
4864 * an error where there's an empty slot with no huge pagecache
4865 * to back it. This way, we avoid allocating a hugepage, and
4866 * the sparse dumpfile avoids allocating disk blocks, but its
4867 * huge holes still show up with zeroes where they need to be.
4869 if (absent
&& (flags
& FOLL_DUMP
) &&
4870 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4878 * We need call hugetlb_fault for both hugepages under migration
4879 * (in which case hugetlb_fault waits for the migration,) and
4880 * hwpoisoned hugepages (in which case we need to prevent the
4881 * caller from accessing to them.) In order to do this, we use
4882 * here is_swap_pte instead of is_hugetlb_entry_migration and
4883 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4884 * both cases, and because we can't follow correct pages
4885 * directly from any kind of swap entries.
4887 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4888 ((flags
& FOLL_WRITE
) &&
4889 !huge_pte_write(huge_ptep_get(pte
)))) {
4891 unsigned int fault_flags
= 0;
4895 if (flags
& FOLL_WRITE
)
4896 fault_flags
|= FAULT_FLAG_WRITE
;
4898 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4899 FAULT_FLAG_KILLABLE
;
4900 if (flags
& FOLL_NOWAIT
)
4901 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4902 FAULT_FLAG_RETRY_NOWAIT
;
4903 if (flags
& FOLL_TRIED
) {
4905 * Note: FAULT_FLAG_ALLOW_RETRY and
4906 * FAULT_FLAG_TRIED can co-exist
4908 fault_flags
|= FAULT_FLAG_TRIED
;
4910 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4911 if (ret
& VM_FAULT_ERROR
) {
4912 err
= vm_fault_to_errno(ret
, flags
);
4916 if (ret
& VM_FAULT_RETRY
) {
4918 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4922 * VM_FAULT_RETRY must not return an
4923 * error, it will return zero
4926 * No need to update "position" as the
4927 * caller will not check it after
4928 * *nr_pages is set to 0.
4935 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4936 page
= pte_page(huge_ptep_get(pte
));
4939 * If subpage information not requested, update counters
4940 * and skip the same_page loop below.
4942 if (!pages
&& !vmas
&& !pfn_offset
&&
4943 (vaddr
+ huge_page_size(h
) < vma
->vm_end
) &&
4944 (remainder
>= pages_per_huge_page(h
))) {
4945 vaddr
+= huge_page_size(h
);
4946 remainder
-= pages_per_huge_page(h
);
4947 i
+= pages_per_huge_page(h
);
4952 refs
= min3(pages_per_huge_page(h
) - pfn_offset
,
4953 (vma
->vm_end
- vaddr
) >> PAGE_SHIFT
, remainder
);
4956 record_subpages_vmas(mem_map_offset(page
, pfn_offset
),
4958 likely(pages
) ? pages
+ i
: NULL
,
4959 vmas
? vmas
+ i
: NULL
);
4963 * try_grab_compound_head() should always succeed here,
4964 * because: a) we hold the ptl lock, and b) we've just
4965 * checked that the huge page is present in the page
4966 * tables. If the huge page is present, then the tail
4967 * pages must also be present. The ptl prevents the
4968 * head page and tail pages from being rearranged in
4969 * any way. So this page must be available at this
4970 * point, unless the page refcount overflowed:
4972 if (WARN_ON_ONCE(!try_grab_compound_head(pages
[i
],
4982 vaddr
+= (refs
<< PAGE_SHIFT
);
4988 *nr_pages
= remainder
;
4990 * setting position is actually required only if remainder is
4991 * not zero but it's faster not to add a "if (remainder)"
4999 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
5001 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
5004 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
5007 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
5008 unsigned long address
, unsigned long end
, pgprot_t newprot
)
5010 struct mm_struct
*mm
= vma
->vm_mm
;
5011 unsigned long start
= address
;
5014 struct hstate
*h
= hstate_vma(vma
);
5015 unsigned long pages
= 0;
5016 bool shared_pmd
= false;
5017 struct mmu_notifier_range range
;
5020 * In the case of shared PMDs, the area to flush could be beyond
5021 * start/end. Set range.start/range.end to cover the maximum possible
5022 * range if PMD sharing is possible.
5024 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
5025 0, vma
, mm
, start
, end
);
5026 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
5028 BUG_ON(address
>= end
);
5029 flush_cache_range(vma
, range
.start
, range
.end
);
5031 mmu_notifier_invalidate_range_start(&range
);
5032 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
5033 for (; address
< end
; address
+= huge_page_size(h
)) {
5035 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
5038 ptl
= huge_pte_lock(h
, mm
, ptep
);
5039 if (huge_pmd_unshare(mm
, vma
, &address
, ptep
)) {
5045 pte
= huge_ptep_get(ptep
);
5046 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
5050 if (unlikely(is_hugetlb_entry_migration(pte
))) {
5051 swp_entry_t entry
= pte_to_swp_entry(pte
);
5053 if (is_write_migration_entry(entry
)) {
5056 make_migration_entry_read(&entry
);
5057 newpte
= swp_entry_to_pte(entry
);
5058 set_huge_swap_pte_at(mm
, address
, ptep
,
5059 newpte
, huge_page_size(h
));
5065 if (!huge_pte_none(pte
)) {
5068 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
5069 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
5070 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
5071 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
5077 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5078 * may have cleared our pud entry and done put_page on the page table:
5079 * once we release i_mmap_rwsem, another task can do the final put_page
5080 * and that page table be reused and filled with junk. If we actually
5081 * did unshare a page of pmds, flush the range corresponding to the pud.
5084 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
5086 flush_hugetlb_tlb_range(vma
, start
, end
);
5088 * No need to call mmu_notifier_invalidate_range() we are downgrading
5089 * page table protection not changing it to point to a new page.
5091 * See Documentation/vm/mmu_notifier.rst
5093 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
5094 mmu_notifier_invalidate_range_end(&range
);
5096 return pages
<< h
->order
;
5099 /* Return true if reservation was successful, false otherwise. */
5100 bool hugetlb_reserve_pages(struct inode
*inode
,
5102 struct vm_area_struct
*vma
,
5103 vm_flags_t vm_flags
)
5106 struct hstate
*h
= hstate_inode(inode
);
5107 struct hugepage_subpool
*spool
= subpool_inode(inode
);
5108 struct resv_map
*resv_map
;
5109 struct hugetlb_cgroup
*h_cg
= NULL
;
5110 long gbl_reserve
, regions_needed
= 0;
5112 /* This should never happen */
5114 VM_WARN(1, "%s called with a negative range\n", __func__
);
5119 * Only apply hugepage reservation if asked. At fault time, an
5120 * attempt will be made for VM_NORESERVE to allocate a page
5121 * without using reserves
5123 if (vm_flags
& VM_NORESERVE
)
5127 * Shared mappings base their reservation on the number of pages that
5128 * are already allocated on behalf of the file. Private mappings need
5129 * to reserve the full area even if read-only as mprotect() may be
5130 * called to make the mapping read-write. Assume !vma is a shm mapping
5132 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
5134 * resv_map can not be NULL as hugetlb_reserve_pages is only
5135 * called for inodes for which resv_maps were created (see
5136 * hugetlbfs_get_inode).
5138 resv_map
= inode_resv_map(inode
);
5140 chg
= region_chg(resv_map
, from
, to
, ®ions_needed
);
5143 /* Private mapping. */
5144 resv_map
= resv_map_alloc();
5150 set_vma_resv_map(vma
, resv_map
);
5151 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
5157 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h
),
5158 chg
* pages_per_huge_page(h
), &h_cg
) < 0)
5161 if (vma
&& !(vma
->vm_flags
& VM_MAYSHARE
) && h_cg
) {
5162 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5165 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map
, h_cg
, h
);
5169 * There must be enough pages in the subpool for the mapping. If
5170 * the subpool has a minimum size, there may be some global
5171 * reservations already in place (gbl_reserve).
5173 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
5174 if (gbl_reserve
< 0)
5175 goto out_uncharge_cgroup
;
5178 * Check enough hugepages are available for the reservation.
5179 * Hand the pages back to the subpool if there are not
5181 if (hugetlb_acct_memory(h
, gbl_reserve
) < 0)
5185 * Account for the reservations made. Shared mappings record regions
5186 * that have reservations as they are shared by multiple VMAs.
5187 * When the last VMA disappears, the region map says how much
5188 * the reservation was and the page cache tells how much of
5189 * the reservation was consumed. Private mappings are per-VMA and
5190 * only the consumed reservations are tracked. When the VMA
5191 * disappears, the original reservation is the VMA size and the
5192 * consumed reservations are stored in the map. Hence, nothing
5193 * else has to be done for private mappings here
5195 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
5196 add
= region_add(resv_map
, from
, to
, regions_needed
, h
, h_cg
);
5198 if (unlikely(add
< 0)) {
5199 hugetlb_acct_memory(h
, -gbl_reserve
);
5201 } else if (unlikely(chg
> add
)) {
5203 * pages in this range were added to the reserve
5204 * map between region_chg and region_add. This
5205 * indicates a race with alloc_huge_page. Adjust
5206 * the subpool and reserve counts modified above
5207 * based on the difference.
5212 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5213 * reference to h_cg->css. See comment below for detail.
5215 hugetlb_cgroup_uncharge_cgroup_rsvd(
5217 (chg
- add
) * pages_per_huge_page(h
), h_cg
);
5219 rsv_adjust
= hugepage_subpool_put_pages(spool
,
5221 hugetlb_acct_memory(h
, -rsv_adjust
);
5224 * The file_regions will hold their own reference to
5225 * h_cg->css. So we should release the reference held
5226 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5229 hugetlb_cgroup_put_rsvd_cgroup(h_cg
);
5235 /* put back original number of pages, chg */
5236 (void)hugepage_subpool_put_pages(spool
, chg
);
5237 out_uncharge_cgroup
:
5238 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h
),
5239 chg
* pages_per_huge_page(h
), h_cg
);
5241 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
5242 /* Only call region_abort if the region_chg succeeded but the
5243 * region_add failed or didn't run.
5245 if (chg
>= 0 && add
< 0)
5246 region_abort(resv_map
, from
, to
, regions_needed
);
5247 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
5248 kref_put(&resv_map
->refs
, resv_map_release
);
5252 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
5255 struct hstate
*h
= hstate_inode(inode
);
5256 struct resv_map
*resv_map
= inode_resv_map(inode
);
5258 struct hugepage_subpool
*spool
= subpool_inode(inode
);
5262 * Since this routine can be called in the evict inode path for all
5263 * hugetlbfs inodes, resv_map could be NULL.
5266 chg
= region_del(resv_map
, start
, end
);
5268 * region_del() can fail in the rare case where a region
5269 * must be split and another region descriptor can not be
5270 * allocated. If end == LONG_MAX, it will not fail.
5276 spin_lock(&inode
->i_lock
);
5277 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
5278 spin_unlock(&inode
->i_lock
);
5281 * If the subpool has a minimum size, the number of global
5282 * reservations to be released may be adjusted.
5284 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
5285 hugetlb_acct_memory(h
, -gbl_reserve
);
5290 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5291 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
5292 struct vm_area_struct
*vma
,
5293 unsigned long addr
, pgoff_t idx
)
5295 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
5297 unsigned long sbase
= saddr
& PUD_MASK
;
5298 unsigned long s_end
= sbase
+ PUD_SIZE
;
5300 /* Allow segments to share if only one is marked locked */
5301 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5302 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
5305 * match the virtual addresses, permission and the alignment of the
5308 if (pmd_index(addr
) != pmd_index(saddr
) ||
5309 vm_flags
!= svm_flags
||
5310 !range_in_vma(svma
, sbase
, s_end
))
5316 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
5318 unsigned long base
= addr
& PUD_MASK
;
5319 unsigned long end
= base
+ PUD_SIZE
;
5322 * check on proper vm_flags and page table alignment
5324 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
5330 * Determine if start,end range within vma could be mapped by shared pmd.
5331 * If yes, adjust start and end to cover range associated with possible
5332 * shared pmd mappings.
5334 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5335 unsigned long *start
, unsigned long *end
)
5337 unsigned long v_start
= ALIGN(vma
->vm_start
, PUD_SIZE
),
5338 v_end
= ALIGN_DOWN(vma
->vm_end
, PUD_SIZE
);
5341 * vma need span at least one aligned PUD size and the start,end range
5342 * must at least partialy within it.
5344 if (!(vma
->vm_flags
& VM_MAYSHARE
) || !(v_end
> v_start
) ||
5345 (*end
<= v_start
) || (*start
>= v_end
))
5348 /* Extend the range to be PUD aligned for a worst case scenario */
5349 if (*start
> v_start
)
5350 *start
= ALIGN_DOWN(*start
, PUD_SIZE
);
5353 *end
= ALIGN(*end
, PUD_SIZE
);
5357 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5358 * and returns the corresponding pte. While this is not necessary for the
5359 * !shared pmd case because we can allocate the pmd later as well, it makes the
5360 * code much cleaner.
5362 * This routine must be called with i_mmap_rwsem held in at least read mode if
5363 * sharing is possible. For hugetlbfs, this prevents removal of any page
5364 * table entries associated with the address space. This is important as we
5365 * are setting up sharing based on existing page table entries (mappings).
5367 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5368 * huge_pte_alloc know that sharing is not possible and do not take
5369 * i_mmap_rwsem as a performance optimization. This is handled by the
5370 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5371 * only required for subsequent processing.
5373 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5375 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
5376 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
5377 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
5379 struct vm_area_struct
*svma
;
5380 unsigned long saddr
;
5385 if (!vma_shareable(vma
, addr
))
5386 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5388 i_mmap_assert_locked(mapping
);
5389 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
5393 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
5395 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
5396 vma_mmu_pagesize(svma
));
5398 get_page(virt_to_page(spte
));
5407 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
5408 if (pud_none(*pud
)) {
5409 pud_populate(mm
, pud
,
5410 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
5413 put_page(virt_to_page(spte
));
5417 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5422 * unmap huge page backed by shared pte.
5424 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5425 * indicated by page_count > 1, unmap is achieved by clearing pud and
5426 * decrementing the ref count. If count == 1, the pte page is not shared.
5428 * Called with page table lock held and i_mmap_rwsem held in write mode.
5430 * returns: 1 successfully unmapped a shared pte page
5431 * 0 the underlying pte page is not shared, or it is the last user
5433 int huge_pmd_unshare(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
5434 unsigned long *addr
, pte_t
*ptep
)
5436 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
5437 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
5438 pud_t
*pud
= pud_offset(p4d
, *addr
);
5440 i_mmap_assert_write_locked(vma
->vm_file
->f_mapping
);
5441 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
5442 if (page_count(virt_to_page(ptep
)) == 1)
5446 put_page(virt_to_page(ptep
));
5448 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
5451 #define want_pmd_share() (1)
5452 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5453 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5458 int huge_pmd_unshare(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
5459 unsigned long *addr
, pte_t
*ptep
)
5464 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5465 unsigned long *start
, unsigned long *end
)
5468 #define want_pmd_share() (0)
5469 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5471 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5472 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
5473 unsigned long addr
, unsigned long sz
)
5480 pgd
= pgd_offset(mm
, addr
);
5481 p4d
= p4d_alloc(mm
, pgd
, addr
);
5484 pud
= pud_alloc(mm
, p4d
, addr
);
5486 if (sz
== PUD_SIZE
) {
5489 BUG_ON(sz
!= PMD_SIZE
);
5490 if (want_pmd_share() && pud_none(*pud
))
5491 pte
= huge_pmd_share(mm
, addr
, pud
);
5493 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5496 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
5502 * huge_pte_offset() - Walk the page table to resolve the hugepage
5503 * entry at address @addr
5505 * Return: Pointer to page table entry (PUD or PMD) for
5506 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5507 * size @sz doesn't match the hugepage size at this level of the page
5510 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
5511 unsigned long addr
, unsigned long sz
)
5518 pgd
= pgd_offset(mm
, addr
);
5519 if (!pgd_present(*pgd
))
5521 p4d
= p4d_offset(pgd
, addr
);
5522 if (!p4d_present(*p4d
))
5525 pud
= pud_offset(p4d
, addr
);
5527 /* must be pud huge, non-present or none */
5528 return (pte_t
*)pud
;
5529 if (!pud_present(*pud
))
5531 /* must have a valid entry and size to go further */
5533 pmd
= pmd_offset(pud
, addr
);
5534 /* must be pmd huge, non-present or none */
5535 return (pte_t
*)pmd
;
5538 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5541 * These functions are overwritable if your architecture needs its own
5544 struct page
* __weak
5545 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
5548 return ERR_PTR(-EINVAL
);
5551 struct page
* __weak
5552 follow_huge_pd(struct vm_area_struct
*vma
,
5553 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
5555 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5559 struct page
* __weak
5560 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
5561 pmd_t
*pmd
, int flags
)
5563 struct page
*page
= NULL
;
5567 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5568 if (WARN_ON_ONCE((flags
& (FOLL_PIN
| FOLL_GET
)) ==
5569 (FOLL_PIN
| FOLL_GET
)))
5573 ptl
= pmd_lockptr(mm
, pmd
);
5576 * make sure that the address range covered by this pmd is not
5577 * unmapped from other threads.
5579 if (!pmd_huge(*pmd
))
5581 pte
= huge_ptep_get((pte_t
*)pmd
);
5582 if (pte_present(pte
)) {
5583 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
5585 * try_grab_page() should always succeed here, because: a) we
5586 * hold the pmd (ptl) lock, and b) we've just checked that the
5587 * huge pmd (head) page is present in the page tables. The ptl
5588 * prevents the head page and tail pages from being rearranged
5589 * in any way. So this page must be available at this point,
5590 * unless the page refcount overflowed:
5592 if (WARN_ON_ONCE(!try_grab_page(page
, flags
))) {
5597 if (is_hugetlb_entry_migration(pte
)) {
5599 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5603 * hwpoisoned entry is treated as no_page_table in
5604 * follow_page_mask().
5612 struct page
* __weak
5613 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5614 pud_t
*pud
, int flags
)
5616 if (flags
& (FOLL_GET
| FOLL_PIN
))
5619 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5622 struct page
* __weak
5623 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5625 if (flags
& (FOLL_GET
| FOLL_PIN
))
5628 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5631 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5635 spin_lock(&hugetlb_lock
);
5636 if (!PageHeadHuge(page
) ||
5637 !HPageMigratable(page
) ||
5638 !get_page_unless_zero(page
)) {
5642 ClearHPageMigratable(page
);
5643 list_move_tail(&page
->lru
, list
);
5645 spin_unlock(&hugetlb_lock
);
5649 void putback_active_hugepage(struct page
*page
)
5651 spin_lock(&hugetlb_lock
);
5652 SetHPageMigratable(page
);
5653 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5654 spin_unlock(&hugetlb_lock
);
5658 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5660 struct hstate
*h
= page_hstate(oldpage
);
5662 hugetlb_cgroup_migrate(oldpage
, newpage
);
5663 set_page_owner_migrate_reason(newpage
, reason
);
5666 * transfer temporary state of the new huge page. This is
5667 * reverse to other transitions because the newpage is going to
5668 * be final while the old one will be freed so it takes over
5669 * the temporary status.
5671 * Also note that we have to transfer the per-node surplus state
5672 * here as well otherwise the global surplus count will not match
5675 if (HPageTemporary(newpage
)) {
5676 int old_nid
= page_to_nid(oldpage
);
5677 int new_nid
= page_to_nid(newpage
);
5679 SetHPageTemporary(oldpage
);
5680 ClearHPageTemporary(newpage
);
5682 spin_lock(&hugetlb_lock
);
5683 if (h
->surplus_huge_pages_node
[old_nid
]) {
5684 h
->surplus_huge_pages_node
[old_nid
]--;
5685 h
->surplus_huge_pages_node
[new_nid
]++;
5687 spin_unlock(&hugetlb_lock
);
5692 static bool cma_reserve_called __initdata
;
5694 static int __init
cmdline_parse_hugetlb_cma(char *p
)
5696 hugetlb_cma_size
= memparse(p
, &p
);
5700 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma
);
5702 void __init
hugetlb_cma_reserve(int order
)
5704 unsigned long size
, reserved
, per_node
;
5707 cma_reserve_called
= true;
5709 if (!hugetlb_cma_size
)
5712 if (hugetlb_cma_size
< (PAGE_SIZE
<< order
)) {
5713 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5714 (PAGE_SIZE
<< order
) / SZ_1M
);
5719 * If 3 GB area is requested on a machine with 4 numa nodes,
5720 * let's allocate 1 GB on first three nodes and ignore the last one.
5722 per_node
= DIV_ROUND_UP(hugetlb_cma_size
, nr_online_nodes
);
5723 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5724 hugetlb_cma_size
/ SZ_1M
, per_node
/ SZ_1M
);
5727 for_each_node_state(nid
, N_ONLINE
) {
5729 char name
[CMA_MAX_NAME
];
5731 size
= min(per_node
, hugetlb_cma_size
- reserved
);
5732 size
= round_up(size
, PAGE_SIZE
<< order
);
5734 snprintf(name
, sizeof(name
), "hugetlb%d", nid
);
5735 res
= cma_declare_contiguous_nid(0, size
, 0, PAGE_SIZE
<< order
,
5737 &hugetlb_cma
[nid
], nid
);
5739 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
5745 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
5748 if (reserved
>= hugetlb_cma_size
)
5753 void __init
hugetlb_cma_check(void)
5755 if (!hugetlb_cma_size
|| cma_reserve_called
)
5758 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
5761 #endif /* CONFIG_CMA */