1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/mmdebug.h>
23 #include <linux/sched/signal.h>
24 #include <linux/rmap.h>
25 #include <linux/string_helpers.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
28 #include <linux/jhash.h>
29 #include <linux/numa.h>
30 #include <linux/llist.h>
33 #include <asm/pgtable.h>
37 #include <linux/hugetlb.h>
38 #include <linux/hugetlb_cgroup.h>
39 #include <linux/node.h>
40 #include <linux/userfaultfd_k.h>
41 #include <linux/page_owner.h>
44 int hugetlb_max_hstate __read_mostly
;
45 unsigned int default_hstate_idx
;
46 struct hstate hstates
[HUGE_MAX_HSTATE
];
48 * Minimum page order among possible hugepage sizes, set to a proper value
51 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
53 __initdata
LIST_HEAD(huge_boot_pages
);
55 /* for command line parsing */
56 static struct hstate
* __initdata parsed_hstate
;
57 static unsigned long __initdata default_hstate_max_huge_pages
;
58 static unsigned long __initdata default_hstate_size
;
59 static bool __initdata parsed_valid_hugepagesz
= true;
62 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
63 * free_huge_pages, and surplus_huge_pages.
65 DEFINE_SPINLOCK(hugetlb_lock
);
68 * Serializes faults on the same logical page. This is used to
69 * prevent spurious OOMs when the hugepage pool is fully utilized.
71 static int num_fault_mutexes
;
72 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
74 static inline bool PageHugeFreed(struct page
*head
)
76 return page_private(head
+ 4) == -1UL;
79 static inline void SetPageHugeFreed(struct page
*head
)
81 set_page_private(head
+ 4, -1UL);
84 static inline void ClearPageHugeFreed(struct page
*head
)
86 set_page_private(head
+ 4, 0);
89 /* Forward declaration */
90 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
92 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
94 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
96 spin_unlock(&spool
->lock
);
98 /* If no pages are used, and no other handles to the subpool
99 * remain, give up any reservations mased on minimum size and
100 * free the subpool */
102 if (spool
->min_hpages
!= -1)
103 hugetlb_acct_memory(spool
->hstate
,
109 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
112 struct hugepage_subpool
*spool
;
114 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
118 spin_lock_init(&spool
->lock
);
120 spool
->max_hpages
= max_hpages
;
122 spool
->min_hpages
= min_hpages
;
124 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
128 spool
->rsv_hpages
= min_hpages
;
133 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
135 spin_lock(&spool
->lock
);
136 BUG_ON(!spool
->count
);
138 unlock_or_release_subpool(spool
);
142 * Subpool accounting for allocating and reserving pages.
143 * Return -ENOMEM if there are not enough resources to satisfy the
144 * the request. Otherwise, return the number of pages by which the
145 * global pools must be adjusted (upward). The returned value may
146 * only be different than the passed value (delta) in the case where
147 * a subpool minimum size must be manitained.
149 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
157 spin_lock(&spool
->lock
);
159 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
160 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
161 spool
->used_hpages
+= delta
;
168 /* minimum size accounting */
169 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
170 if (delta
> spool
->rsv_hpages
) {
172 * Asking for more reserves than those already taken on
173 * behalf of subpool. Return difference.
175 ret
= delta
- spool
->rsv_hpages
;
176 spool
->rsv_hpages
= 0;
178 ret
= 0; /* reserves already accounted for */
179 spool
->rsv_hpages
-= delta
;
184 spin_unlock(&spool
->lock
);
189 * Subpool accounting for freeing and unreserving pages.
190 * Return the number of global page reservations that must be dropped.
191 * The return value may only be different than the passed value (delta)
192 * in the case where a subpool minimum size must be maintained.
194 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
202 spin_lock(&spool
->lock
);
204 if (spool
->max_hpages
!= -1) /* maximum size accounting */
205 spool
->used_hpages
-= delta
;
207 /* minimum size accounting */
208 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
209 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
212 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
214 spool
->rsv_hpages
+= delta
;
215 if (spool
->rsv_hpages
> spool
->min_hpages
)
216 spool
->rsv_hpages
= spool
->min_hpages
;
220 * If hugetlbfs_put_super couldn't free spool due to an outstanding
221 * quota reference, free it now.
223 unlock_or_release_subpool(spool
);
228 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
230 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
233 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
235 return subpool_inode(file_inode(vma
->vm_file
));
239 * Region tracking -- allows tracking of reservations and instantiated pages
240 * across the pages in a mapping.
242 * The region data structures are embedded into a resv_map and protected
243 * by a resv_map's lock. The set of regions within the resv_map represent
244 * reservations for huge pages, or huge pages that have already been
245 * instantiated within the map. The from and to elements are huge page
246 * indicies into the associated mapping. from indicates the starting index
247 * of the region. to represents the first index past the end of the region.
249 * For example, a file region structure with from == 0 and to == 4 represents
250 * four huge pages in a mapping. It is important to note that the to element
251 * represents the first element past the end of the region. This is used in
252 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
254 * Interval notation of the form [from, to) will be used to indicate that
255 * the endpoint from is inclusive and to is exclusive.
258 struct list_head link
;
264 * Add the huge page range represented by [f, t) to the reserve
265 * map. In the normal case, existing regions will be expanded
266 * to accommodate the specified range. Sufficient regions should
267 * exist for expansion due to the previous call to region_chg
268 * with the same range. However, it is possible that region_del
269 * could have been called after region_chg and modifed the map
270 * in such a way that no region exists to be expanded. In this
271 * case, pull a region descriptor from the cache associated with
272 * the map and use that for the new range.
274 * Return the number of new huge pages added to the map. This
275 * number is greater than or equal to zero.
277 static long region_add(struct resv_map
*resv
, long f
, long t
)
279 struct list_head
*head
= &resv
->regions
;
280 struct file_region
*rg
, *nrg
, *trg
;
283 spin_lock(&resv
->lock
);
284 /* Locate the region we are either in or before. */
285 list_for_each_entry(rg
, head
, link
)
290 * If no region exists which can be expanded to include the
291 * specified range, the list must have been modified by an
292 * interleving call to region_del(). Pull a region descriptor
293 * from the cache and use it for this range.
295 if (&rg
->link
== head
|| t
< rg
->from
) {
296 VM_BUG_ON(resv
->region_cache_count
<= 0);
298 resv
->region_cache_count
--;
299 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
301 list_del(&nrg
->link
);
305 list_add(&nrg
->link
, rg
->link
.prev
);
311 /* Round our left edge to the current segment if it encloses us. */
315 /* Check for and consume any regions we now overlap with. */
317 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
318 if (&rg
->link
== head
)
323 /* If this area reaches higher then extend our area to
324 * include it completely. If this is not the first area
325 * which we intend to reuse, free it. */
329 /* Decrement return value by the deleted range.
330 * Another range will span this area so that by
331 * end of routine add will be >= zero
333 add
-= (rg
->to
- rg
->from
);
339 add
+= (nrg
->from
- f
); /* Added to beginning of region */
341 add
+= t
- nrg
->to
; /* Added to end of region */
345 resv
->adds_in_progress
--;
346 spin_unlock(&resv
->lock
);
352 * Examine the existing reserve map and determine how many
353 * huge pages in the specified range [f, t) are NOT currently
354 * represented. This routine is called before a subsequent
355 * call to region_add that will actually modify the reserve
356 * map to add the specified range [f, t). region_chg does
357 * not change the number of huge pages represented by the
358 * map. However, if the existing regions in the map can not
359 * be expanded to represent the new range, a new file_region
360 * structure is added to the map as a placeholder. This is
361 * so that the subsequent region_add call will have all the
362 * regions it needs and will not fail.
364 * Upon entry, region_chg will also examine the cache of region descriptors
365 * associated with the map. If there are not enough descriptors cached, one
366 * will be allocated for the in progress add operation.
368 * Returns the number of huge pages that need to be added to the existing
369 * reservation map for the range [f, t). This number is greater or equal to
370 * zero. -ENOMEM is returned if a new file_region structure or cache entry
371 * is needed and can not be allocated.
373 static long region_chg(struct resv_map
*resv
, long f
, long t
)
375 struct list_head
*head
= &resv
->regions
;
376 struct file_region
*rg
, *nrg
= NULL
;
380 spin_lock(&resv
->lock
);
382 resv
->adds_in_progress
++;
385 * Check for sufficient descriptors in the cache to accommodate
386 * the number of in progress add operations.
388 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
389 struct file_region
*trg
;
391 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
392 /* Must drop lock to allocate a new descriptor. */
393 resv
->adds_in_progress
--;
394 spin_unlock(&resv
->lock
);
396 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
402 spin_lock(&resv
->lock
);
403 list_add(&trg
->link
, &resv
->region_cache
);
404 resv
->region_cache_count
++;
408 /* Locate the region we are before or in. */
409 list_for_each_entry(rg
, head
, link
)
413 /* If we are below the current region then a new region is required.
414 * Subtle, allocate a new region at the position but make it zero
415 * size such that we can guarantee to record the reservation. */
416 if (&rg
->link
== head
|| t
< rg
->from
) {
418 resv
->adds_in_progress
--;
419 spin_unlock(&resv
->lock
);
420 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
426 INIT_LIST_HEAD(&nrg
->link
);
430 list_add(&nrg
->link
, rg
->link
.prev
);
435 /* Round our left edge to the current segment if it encloses us. */
440 /* Check for and consume any regions we now overlap with. */
441 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
442 if (&rg
->link
== head
)
447 /* We overlap with this area, if it extends further than
448 * us then we must extend ourselves. Account for its
449 * existing reservation. */
454 chg
-= rg
->to
- rg
->from
;
458 spin_unlock(&resv
->lock
);
459 /* We already know we raced and no longer need the new region */
463 spin_unlock(&resv
->lock
);
468 * Abort the in progress add operation. The adds_in_progress field
469 * of the resv_map keeps track of the operations in progress between
470 * calls to region_chg and region_add. Operations are sometimes
471 * aborted after the call to region_chg. In such cases, region_abort
472 * is called to decrement the adds_in_progress counter.
474 * NOTE: The range arguments [f, t) are not needed or used in this
475 * routine. They are kept to make reading the calling code easier as
476 * arguments will match the associated region_chg call.
478 static void region_abort(struct resv_map
*resv
, long f
, long t
)
480 spin_lock(&resv
->lock
);
481 VM_BUG_ON(!resv
->region_cache_count
);
482 resv
->adds_in_progress
--;
483 spin_unlock(&resv
->lock
);
487 * Delete the specified range [f, t) from the reserve map. If the
488 * t parameter is LONG_MAX, this indicates that ALL regions after f
489 * should be deleted. Locate the regions which intersect [f, t)
490 * and either trim, delete or split the existing regions.
492 * Returns the number of huge pages deleted from the reserve map.
493 * In the normal case, the return value is zero or more. In the
494 * case where a region must be split, a new region descriptor must
495 * be allocated. If the allocation fails, -ENOMEM will be returned.
496 * NOTE: If the parameter t == LONG_MAX, then we will never split
497 * a region and possibly return -ENOMEM. Callers specifying
498 * t == LONG_MAX do not need to check for -ENOMEM error.
500 static long region_del(struct resv_map
*resv
, long f
, long t
)
502 struct list_head
*head
= &resv
->regions
;
503 struct file_region
*rg
, *trg
;
504 struct file_region
*nrg
= NULL
;
508 spin_lock(&resv
->lock
);
509 list_for_each_entry_safe(rg
, trg
, head
, link
) {
511 * Skip regions before the range to be deleted. file_region
512 * ranges are normally of the form [from, to). However, there
513 * may be a "placeholder" entry in the map which is of the form
514 * (from, to) with from == to. Check for placeholder entries
515 * at the beginning of the range to be deleted.
517 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
523 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
525 * Check for an entry in the cache before dropping
526 * lock and attempting allocation.
529 resv
->region_cache_count
> resv
->adds_in_progress
) {
530 nrg
= list_first_entry(&resv
->region_cache
,
533 list_del(&nrg
->link
);
534 resv
->region_cache_count
--;
538 spin_unlock(&resv
->lock
);
539 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
547 /* New entry for end of split region */
550 INIT_LIST_HEAD(&nrg
->link
);
552 /* Original entry is trimmed */
555 list_add(&nrg
->link
, &rg
->link
);
560 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
561 del
+= rg
->to
- rg
->from
;
567 if (f
<= rg
->from
) { /* Trim beginning of region */
570 } else { /* Trim end of region */
576 spin_unlock(&resv
->lock
);
582 * A rare out of memory error was encountered which prevented removal of
583 * the reserve map region for a page. The huge page itself was free'ed
584 * and removed from the page cache. This routine will adjust the subpool
585 * usage count, and the global reserve count if needed. By incrementing
586 * these counts, the reserve map entry which could not be deleted will
587 * appear as a "reserved" entry instead of simply dangling with incorrect
590 void hugetlb_fix_reserve_counts(struct inode
*inode
)
592 struct hugepage_subpool
*spool
= subpool_inode(inode
);
594 bool reserved
= false;
596 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
597 if (rsv_adjust
> 0) {
598 struct hstate
*h
= hstate_inode(inode
);
600 if (!hugetlb_acct_memory(h
, 1))
602 } else if (!rsv_adjust
) {
607 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
611 * Count and return the number of huge pages in the reserve map
612 * that intersect with the range [f, t).
614 static long region_count(struct resv_map
*resv
, long f
, long t
)
616 struct list_head
*head
= &resv
->regions
;
617 struct file_region
*rg
;
620 spin_lock(&resv
->lock
);
621 /* Locate each segment we overlap with, and count that overlap. */
622 list_for_each_entry(rg
, head
, link
) {
631 seg_from
= max(rg
->from
, f
);
632 seg_to
= min(rg
->to
, t
);
634 chg
+= seg_to
- seg_from
;
636 spin_unlock(&resv
->lock
);
642 * Convert the address within this vma to the page offset within
643 * the mapping, in pagecache page units; huge pages here.
645 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
646 struct vm_area_struct
*vma
, unsigned long address
)
648 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
649 (vma
->vm_pgoff
>> huge_page_order(h
));
652 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
653 unsigned long address
)
655 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
657 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
660 * Return the size of the pages allocated when backing a VMA. In the majority
661 * cases this will be same size as used by the page table entries.
663 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
665 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
666 return vma
->vm_ops
->pagesize(vma
);
669 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
672 * Return the page size being used by the MMU to back a VMA. In the majority
673 * of cases, the page size used by the kernel matches the MMU size. On
674 * architectures where it differs, an architecture-specific 'strong'
675 * version of this symbol is required.
677 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
679 return vma_kernel_pagesize(vma
);
683 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
684 * bits of the reservation map pointer, which are always clear due to
687 #define HPAGE_RESV_OWNER (1UL << 0)
688 #define HPAGE_RESV_UNMAPPED (1UL << 1)
689 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
692 * These helpers are used to track how many pages are reserved for
693 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
694 * is guaranteed to have their future faults succeed.
696 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
697 * the reserve counters are updated with the hugetlb_lock held. It is safe
698 * to reset the VMA at fork() time as it is not in use yet and there is no
699 * chance of the global counters getting corrupted as a result of the values.
701 * The private mapping reservation is represented in a subtly different
702 * manner to a shared mapping. A shared mapping has a region map associated
703 * with the underlying file, this region map represents the backing file
704 * pages which have ever had a reservation assigned which this persists even
705 * after the page is instantiated. A private mapping has a region map
706 * associated with the original mmap which is attached to all VMAs which
707 * reference it, this region map represents those offsets which have consumed
708 * reservation ie. where pages have been instantiated.
710 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
712 return (unsigned long)vma
->vm_private_data
;
715 static void set_vma_private_data(struct vm_area_struct
*vma
,
718 vma
->vm_private_data
= (void *)value
;
721 struct resv_map
*resv_map_alloc(void)
723 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
724 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
726 if (!resv_map
|| !rg
) {
732 kref_init(&resv_map
->refs
);
733 spin_lock_init(&resv_map
->lock
);
734 INIT_LIST_HEAD(&resv_map
->regions
);
736 resv_map
->adds_in_progress
= 0;
738 INIT_LIST_HEAD(&resv_map
->region_cache
);
739 list_add(&rg
->link
, &resv_map
->region_cache
);
740 resv_map
->region_cache_count
= 1;
745 void resv_map_release(struct kref
*ref
)
747 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
748 struct list_head
*head
= &resv_map
->region_cache
;
749 struct file_region
*rg
, *trg
;
751 /* Clear out any active regions before we release the map. */
752 region_del(resv_map
, 0, LONG_MAX
);
754 /* ... and any entries left in the cache */
755 list_for_each_entry_safe(rg
, trg
, head
, link
) {
760 VM_BUG_ON(resv_map
->adds_in_progress
);
765 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
768 * At inode evict time, i_mapping may not point to the original
769 * address space within the inode. This original address space
770 * contains the pointer to the resv_map. So, always use the
771 * address space embedded within the inode.
772 * The VERY common case is inode->mapping == &inode->i_data but,
773 * this may not be true for device special inodes.
775 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
778 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
780 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
781 if (vma
->vm_flags
& VM_MAYSHARE
) {
782 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
783 struct inode
*inode
= mapping
->host
;
785 return inode_resv_map(inode
);
788 return (struct resv_map
*)(get_vma_private_data(vma
) &
793 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
795 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
796 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
798 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
799 HPAGE_RESV_MASK
) | (unsigned long)map
);
802 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
804 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
805 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
807 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
810 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
812 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
814 return (get_vma_private_data(vma
) & flag
) != 0;
817 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
818 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
820 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
821 if (!(vma
->vm_flags
& VM_MAYSHARE
))
822 vma
->vm_private_data
= (void *)0;
825 /* Returns true if the VMA has associated reserve pages */
826 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
828 if (vma
->vm_flags
& VM_NORESERVE
) {
830 * This address is already reserved by other process(chg == 0),
831 * so, we should decrement reserved count. Without decrementing,
832 * reserve count remains after releasing inode, because this
833 * allocated page will go into page cache and is regarded as
834 * coming from reserved pool in releasing step. Currently, we
835 * don't have any other solution to deal with this situation
836 * properly, so add work-around here.
838 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
844 /* Shared mappings always use reserves */
845 if (vma
->vm_flags
& VM_MAYSHARE
) {
847 * We know VM_NORESERVE is not set. Therefore, there SHOULD
848 * be a region map for all pages. The only situation where
849 * there is no region map is if a hole was punched via
850 * fallocate. In this case, there really are no reverves to
851 * use. This situation is indicated if chg != 0.
860 * Only the process that called mmap() has reserves for
863 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
865 * Like the shared case above, a hole punch or truncate
866 * could have been performed on the private mapping.
867 * Examine the value of chg to determine if reserves
868 * actually exist or were previously consumed.
869 * Very Subtle - The value of chg comes from a previous
870 * call to vma_needs_reserves(). The reserve map for
871 * private mappings has different (opposite) semantics
872 * than that of shared mappings. vma_needs_reserves()
873 * has already taken this difference in semantics into
874 * account. Therefore, the meaning of chg is the same
875 * as in the shared case above. Code could easily be
876 * combined, but keeping it separate draws attention to
877 * subtle differences.
888 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
890 int nid
= page_to_nid(page
);
891 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
892 h
->free_huge_pages
++;
893 h
->free_huge_pages_node
[nid
]++;
894 SetPageHugeFreed(page
);
897 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
901 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
902 if (!PageHWPoison(page
))
905 * if 'non-isolated free hugepage' not found on the list,
906 * the allocation fails.
908 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
910 list_move(&page
->lru
, &h
->hugepage_activelist
);
911 set_page_refcounted(page
);
912 ClearPageHugeFreed(page
);
913 h
->free_huge_pages
--;
914 h
->free_huge_pages_node
[nid
]--;
918 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
921 unsigned int cpuset_mems_cookie
;
922 struct zonelist
*zonelist
;
925 int node
= NUMA_NO_NODE
;
927 zonelist
= node_zonelist(nid
, gfp_mask
);
930 cpuset_mems_cookie
= read_mems_allowed_begin();
931 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
934 if (!cpuset_zone_allowed(zone
, gfp_mask
))
937 * no need to ask again on the same node. Pool is node rather than
940 if (zone_to_nid(zone
) == node
)
942 node
= zone_to_nid(zone
);
944 page
= dequeue_huge_page_node_exact(h
, node
);
948 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
954 /* Movability of hugepages depends on migration support. */
955 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
957 if (hugepage_movable_supported(h
))
958 return GFP_HIGHUSER_MOVABLE
;
963 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
964 struct vm_area_struct
*vma
,
965 unsigned long address
, int avoid_reserve
,
969 struct mempolicy
*mpol
;
971 nodemask_t
*nodemask
;
975 * A child process with MAP_PRIVATE mappings created by their parent
976 * have no page reserves. This check ensures that reservations are
977 * not "stolen". The child may still get SIGKILLed
979 if (!vma_has_reserves(vma
, chg
) &&
980 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
983 /* If reserves cannot be used, ensure enough pages are in the pool */
984 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
987 gfp_mask
= htlb_alloc_mask(h
);
988 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
989 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
990 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
991 SetPagePrivate(page
);
992 h
->resv_huge_pages
--;
1003 * common helper functions for hstate_next_node_to_{alloc|free}.
1004 * We may have allocated or freed a huge page based on a different
1005 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1006 * be outside of *nodes_allowed. Ensure that we use an allowed
1007 * node for alloc or free.
1009 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1011 nid
= next_node_in(nid
, *nodes_allowed
);
1012 VM_BUG_ON(nid
>= MAX_NUMNODES
);
1017 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
1019 if (!node_isset(nid
, *nodes_allowed
))
1020 nid
= next_node_allowed(nid
, nodes_allowed
);
1025 * returns the previously saved node ["this node"] from which to
1026 * allocate a persistent huge page for the pool and advance the
1027 * next node from which to allocate, handling wrap at end of node
1030 static int hstate_next_node_to_alloc(struct hstate
*h
,
1031 nodemask_t
*nodes_allowed
)
1035 VM_BUG_ON(!nodes_allowed
);
1037 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1038 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1044 * helper for free_pool_huge_page() - return the previously saved
1045 * node ["this node"] from which to free a huge page. Advance the
1046 * next node id whether or not we find a free huge page to free so
1047 * that the next attempt to free addresses the next node.
1049 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1053 VM_BUG_ON(!nodes_allowed
);
1055 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1056 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1061 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1062 for (nr_nodes = nodes_weight(*mask); \
1064 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1067 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1068 for (nr_nodes = nodes_weight(*mask); \
1070 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1073 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1074 static void destroy_compound_gigantic_page(struct page
*page
,
1078 int nr_pages
= 1 << order
;
1079 struct page
*p
= page
+ 1;
1081 atomic_set(compound_mapcount_ptr(page
), 0);
1082 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1083 clear_compound_head(p
);
1084 set_page_refcounted(p
);
1087 set_compound_order(page
, 0);
1088 __ClearPageHead(page
);
1091 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1093 free_contig_range(page_to_pfn(page
), 1 << order
);
1096 #ifdef CONFIG_CONTIG_ALLOC
1097 static int __alloc_gigantic_page(unsigned long start_pfn
,
1098 unsigned long nr_pages
, gfp_t gfp_mask
)
1100 unsigned long end_pfn
= start_pfn
+ nr_pages
;
1101 return alloc_contig_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
,
1105 static bool pfn_range_valid_gigantic(struct zone
*z
,
1106 unsigned long start_pfn
, unsigned long nr_pages
)
1108 unsigned long i
, end_pfn
= start_pfn
+ nr_pages
;
1111 for (i
= start_pfn
; i
< end_pfn
; i
++) {
1112 page
= pfn_to_online_page(i
);
1116 if (page_zone(page
) != z
)
1119 if (PageReserved(page
))
1122 if (page_count(page
) > 0)
1132 static bool zone_spans_last_pfn(const struct zone
*zone
,
1133 unsigned long start_pfn
, unsigned long nr_pages
)
1135 unsigned long last_pfn
= start_pfn
+ nr_pages
- 1;
1136 return zone_spans_pfn(zone
, last_pfn
);
1139 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1140 int nid
, nodemask_t
*nodemask
)
1142 unsigned int order
= huge_page_order(h
);
1143 unsigned long nr_pages
= 1 << order
;
1144 unsigned long ret
, pfn
, flags
;
1145 struct zonelist
*zonelist
;
1149 zonelist
= node_zonelist(nid
, gfp_mask
);
1150 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nodemask
) {
1151 spin_lock_irqsave(&zone
->lock
, flags
);
1153 pfn
= ALIGN(zone
->zone_start_pfn
, nr_pages
);
1154 while (zone_spans_last_pfn(zone
, pfn
, nr_pages
)) {
1155 if (pfn_range_valid_gigantic(zone
, pfn
, nr_pages
)) {
1157 * We release the zone lock here because
1158 * alloc_contig_range() will also lock the zone
1159 * at some point. If there's an allocation
1160 * spinning on this lock, it may win the race
1161 * and cause alloc_contig_range() to fail...
1163 spin_unlock_irqrestore(&zone
->lock
, flags
);
1164 ret
= __alloc_gigantic_page(pfn
, nr_pages
, gfp_mask
);
1166 return pfn_to_page(pfn
);
1167 spin_lock_irqsave(&zone
->lock
, flags
);
1172 spin_unlock_irqrestore(&zone
->lock
, flags
);
1178 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1179 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1180 #else /* !CONFIG_CONTIG_ALLOC */
1181 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1182 int nid
, nodemask_t
*nodemask
)
1186 #endif /* CONFIG_CONTIG_ALLOC */
1188 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1189 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1190 int nid
, nodemask_t
*nodemask
)
1194 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1195 static inline void destroy_compound_gigantic_page(struct page
*page
,
1196 unsigned int order
) { }
1199 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1202 struct page
*subpage
= page
;
1204 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1208 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1209 for (i
= 0; i
< pages_per_huge_page(h
);
1210 i
++, subpage
= mem_map_next(subpage
, page
, i
)) {
1211 subpage
->flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1212 1 << PG_referenced
| 1 << PG_dirty
|
1213 1 << PG_active
| 1 << PG_private
|
1216 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1217 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1218 set_page_refcounted(page
);
1219 if (hstate_is_gigantic(h
)) {
1220 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1221 free_gigantic_page(page
, huge_page_order(h
));
1223 __free_pages(page
, huge_page_order(h
));
1227 struct hstate
*size_to_hstate(unsigned long size
)
1231 for_each_hstate(h
) {
1232 if (huge_page_size(h
) == size
)
1239 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1240 * to hstate->hugepage_activelist.)
1242 * This function can be called for tail pages, but never returns true for them.
1244 bool page_huge_active(struct page
*page
)
1246 return PageHeadHuge(page
) && PagePrivate(&page
[1]);
1249 /* never called for tail page */
1250 void set_page_huge_active(struct page
*page
)
1252 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1253 SetPagePrivate(&page
[1]);
1256 static void clear_page_huge_active(struct page
*page
)
1258 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1259 ClearPagePrivate(&page
[1]);
1263 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1266 static inline bool PageHugeTemporary(struct page
*page
)
1268 if (!PageHuge(page
))
1271 return (unsigned long)page
[2].mapping
== -1U;
1274 static inline void SetPageHugeTemporary(struct page
*page
)
1276 page
[2].mapping
= (void *)-1U;
1279 static inline void ClearPageHugeTemporary(struct page
*page
)
1281 page
[2].mapping
= NULL
;
1284 static void __free_huge_page(struct page
*page
)
1287 * Can't pass hstate in here because it is called from the
1288 * compound page destructor.
1290 struct hstate
*h
= page_hstate(page
);
1291 int nid
= page_to_nid(page
);
1292 struct hugepage_subpool
*spool
=
1293 (struct hugepage_subpool
*)page_private(page
);
1294 bool restore_reserve
;
1296 VM_BUG_ON_PAGE(page_count(page
), page
);
1297 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1299 set_page_private(page
, 0);
1300 page
->mapping
= NULL
;
1301 restore_reserve
= PagePrivate(page
);
1302 ClearPagePrivate(page
);
1305 * If PagePrivate() was set on page, page allocation consumed a
1306 * reservation. If the page was associated with a subpool, there
1307 * would have been a page reserved in the subpool before allocation
1308 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1309 * reservtion, do not call hugepage_subpool_put_pages() as this will
1310 * remove the reserved page from the subpool.
1312 if (!restore_reserve
) {
1314 * A return code of zero implies that the subpool will be
1315 * under its minimum size if the reservation is not restored
1316 * after page is free. Therefore, force restore_reserve
1319 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1320 restore_reserve
= true;
1323 spin_lock(&hugetlb_lock
);
1324 clear_page_huge_active(page
);
1325 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1326 pages_per_huge_page(h
), page
);
1327 if (restore_reserve
)
1328 h
->resv_huge_pages
++;
1330 if (PageHugeTemporary(page
)) {
1331 list_del(&page
->lru
);
1332 ClearPageHugeTemporary(page
);
1333 update_and_free_page(h
, page
);
1334 } else if (h
->surplus_huge_pages_node
[nid
]) {
1335 /* remove the page from active list */
1336 list_del(&page
->lru
);
1337 update_and_free_page(h
, page
);
1338 h
->surplus_huge_pages
--;
1339 h
->surplus_huge_pages_node
[nid
]--;
1341 arch_clear_hugepage_flags(page
);
1342 enqueue_huge_page(h
, page
);
1344 spin_unlock(&hugetlb_lock
);
1348 * As free_huge_page() can be called from a non-task context, we have
1349 * to defer the actual freeing in a workqueue to prevent potential
1350 * hugetlb_lock deadlock.
1352 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1353 * be freed and frees them one-by-one. As the page->mapping pointer is
1354 * going to be cleared in __free_huge_page() anyway, it is reused as the
1355 * llist_node structure of a lockless linked list of huge pages to be freed.
1357 static LLIST_HEAD(hpage_freelist
);
1359 static void free_hpage_workfn(struct work_struct
*work
)
1361 struct llist_node
*node
;
1364 node
= llist_del_all(&hpage_freelist
);
1367 page
= container_of((struct address_space
**)node
,
1368 struct page
, mapping
);
1370 __free_huge_page(page
);
1373 static DECLARE_WORK(free_hpage_work
, free_hpage_workfn
);
1375 void free_huge_page(struct page
*page
)
1378 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1382 * Only call schedule_work() if hpage_freelist is previously
1383 * empty. Otherwise, schedule_work() had been called but the
1384 * workfn hasn't retrieved the list yet.
1386 if (llist_add((struct llist_node
*)&page
->mapping
,
1388 schedule_work(&free_hpage_work
);
1392 __free_huge_page(page
);
1395 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1397 INIT_LIST_HEAD(&page
->lru
);
1398 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1399 spin_lock(&hugetlb_lock
);
1400 set_hugetlb_cgroup(page
, NULL
);
1402 h
->nr_huge_pages_node
[nid
]++;
1403 ClearPageHugeFreed(page
);
1404 spin_unlock(&hugetlb_lock
);
1407 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1410 int nr_pages
= 1 << order
;
1411 struct page
*p
= page
+ 1;
1413 /* we rely on prep_new_huge_page to set the destructor */
1414 set_compound_order(page
, order
);
1415 __ClearPageReserved(page
);
1416 __SetPageHead(page
);
1417 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1419 * For gigantic hugepages allocated through bootmem at
1420 * boot, it's safer to be consistent with the not-gigantic
1421 * hugepages and clear the PG_reserved bit from all tail pages
1422 * too. Otherwse drivers using get_user_pages() to access tail
1423 * pages may get the reference counting wrong if they see
1424 * PG_reserved set on a tail page (despite the head page not
1425 * having PG_reserved set). Enforcing this consistency between
1426 * head and tail pages allows drivers to optimize away a check
1427 * on the head page when they need know if put_page() is needed
1428 * after get_user_pages().
1430 __ClearPageReserved(p
);
1431 set_page_count(p
, 0);
1432 set_compound_head(p
, page
);
1434 atomic_set(compound_mapcount_ptr(page
), -1);
1438 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1439 * transparent huge pages. See the PageTransHuge() documentation for more
1442 int PageHuge(struct page
*page
)
1444 if (!PageCompound(page
))
1447 page
= compound_head(page
);
1448 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1450 EXPORT_SYMBOL_GPL(PageHuge
);
1453 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1454 * normal or transparent huge pages.
1456 int PageHeadHuge(struct page
*page_head
)
1458 if (!PageHead(page_head
))
1461 return get_compound_page_dtor(page_head
) == free_huge_page
;
1464 pgoff_t
hugetlb_basepage_index(struct page
*page
)
1466 struct page
*page_head
= compound_head(page
);
1467 pgoff_t index
= page_index(page_head
);
1468 unsigned long compound_idx
;
1470 if (compound_order(page_head
) >= MAX_ORDER
)
1471 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1473 compound_idx
= page
- page_head
;
1475 return (index
<< compound_order(page_head
)) + compound_idx
;
1478 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1479 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1480 nodemask_t
*node_alloc_noretry
)
1482 int order
= huge_page_order(h
);
1484 bool alloc_try_hard
= true;
1487 * By default we always try hard to allocate the page with
1488 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1489 * a loop (to adjust global huge page counts) and previous allocation
1490 * failed, do not continue to try hard on the same node. Use the
1491 * node_alloc_noretry bitmap to manage this state information.
1493 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1494 alloc_try_hard
= false;
1495 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1497 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1498 if (nid
== NUMA_NO_NODE
)
1499 nid
= numa_mem_id();
1500 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1502 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1504 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1507 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1508 * indicates an overall state change. Clear bit so that we resume
1509 * normal 'try hard' allocations.
1511 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1512 node_clear(nid
, *node_alloc_noretry
);
1515 * If we tried hard to get a page but failed, set bit so that
1516 * subsequent attempts will not try as hard until there is an
1517 * overall state change.
1519 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1520 node_set(nid
, *node_alloc_noretry
);
1526 * Common helper to allocate a fresh hugetlb page. All specific allocators
1527 * should use this function to get new hugetlb pages
1529 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1530 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1531 nodemask_t
*node_alloc_noretry
)
1535 if (hstate_is_gigantic(h
))
1536 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1538 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1539 nid
, nmask
, node_alloc_noretry
);
1543 if (hstate_is_gigantic(h
))
1544 prep_compound_gigantic_page(page
, huge_page_order(h
));
1545 prep_new_huge_page(h
, page
, page_to_nid(page
));
1551 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1554 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1555 nodemask_t
*node_alloc_noretry
)
1559 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1561 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1562 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1563 node_alloc_noretry
);
1571 put_page(page
); /* free it into the hugepage allocator */
1577 * Free huge page from pool from next node to free.
1578 * Attempt to keep persistent huge pages more or less
1579 * balanced over allowed nodes.
1580 * Called with hugetlb_lock locked.
1582 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1588 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1590 * If we're returning unused surplus pages, only examine
1591 * nodes with surplus pages.
1593 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1594 !list_empty(&h
->hugepage_freelists
[node
])) {
1596 list_entry(h
->hugepage_freelists
[node
].next
,
1598 list_del(&page
->lru
);
1599 h
->free_huge_pages
--;
1600 h
->free_huge_pages_node
[node
]--;
1602 h
->surplus_huge_pages
--;
1603 h
->surplus_huge_pages_node
[node
]--;
1605 update_and_free_page(h
, page
);
1615 * Dissolve a given free hugepage into free buddy pages. This function does
1616 * nothing for in-use hugepages and non-hugepages.
1617 * This function returns values like below:
1619 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1620 * (allocated or reserved.)
1621 * 0: successfully dissolved free hugepages or the page is not a
1622 * hugepage (considered as already dissolved)
1624 int dissolve_free_huge_page(struct page
*page
)
1629 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1630 if (!PageHuge(page
))
1633 spin_lock(&hugetlb_lock
);
1634 if (!PageHuge(page
)) {
1639 if (!page_count(page
)) {
1640 struct page
*head
= compound_head(page
);
1641 struct hstate
*h
= page_hstate(head
);
1642 int nid
= page_to_nid(head
);
1643 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1647 * We should make sure that the page is already on the free list
1648 * when it is dissolved.
1650 if (unlikely(!PageHugeFreed(head
))) {
1651 spin_unlock(&hugetlb_lock
);
1655 * Theoretically, we should return -EBUSY when we
1656 * encounter this race. In fact, we have a chance
1657 * to successfully dissolve the page if we do a
1658 * retry. Because the race window is quite small.
1659 * If we seize this opportunity, it is an optimization
1660 * for increasing the success rate of dissolving page.
1666 * Move PageHWPoison flag from head page to the raw error page,
1667 * which makes any subpages rather than the error page reusable.
1669 if (PageHWPoison(head
) && page
!= head
) {
1670 SetPageHWPoison(page
);
1671 ClearPageHWPoison(head
);
1673 list_del(&head
->lru
);
1674 h
->free_huge_pages
--;
1675 h
->free_huge_pages_node
[nid
]--;
1676 h
->max_huge_pages
--;
1677 update_and_free_page(h
, head
);
1681 spin_unlock(&hugetlb_lock
);
1686 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1687 * make specified memory blocks removable from the system.
1688 * Note that this will dissolve a free gigantic hugepage completely, if any
1689 * part of it lies within the given range.
1690 * Also note that if dissolve_free_huge_page() returns with an error, all
1691 * free hugepages that were dissolved before that error are lost.
1693 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1699 if (!hugepages_supported())
1702 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1703 page
= pfn_to_page(pfn
);
1704 rc
= dissolve_free_huge_page(page
);
1713 * Allocates a fresh surplus page from the page allocator.
1715 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1716 int nid
, nodemask_t
*nmask
)
1718 struct page
*page
= NULL
;
1720 if (hstate_is_gigantic(h
))
1723 spin_lock(&hugetlb_lock
);
1724 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1726 spin_unlock(&hugetlb_lock
);
1728 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1732 spin_lock(&hugetlb_lock
);
1734 * We could have raced with the pool size change.
1735 * Double check that and simply deallocate the new page
1736 * if we would end up overcommiting the surpluses. Abuse
1737 * temporary page to workaround the nasty free_huge_page
1740 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1741 SetPageHugeTemporary(page
);
1742 spin_unlock(&hugetlb_lock
);
1746 h
->surplus_huge_pages
++;
1747 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1751 spin_unlock(&hugetlb_lock
);
1756 struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1757 int nid
, nodemask_t
*nmask
)
1761 if (hstate_is_gigantic(h
))
1764 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1769 * We do not account these pages as surplus because they are only
1770 * temporary and will be released properly on the last reference
1772 SetPageHugeTemporary(page
);
1778 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1781 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1782 struct vm_area_struct
*vma
, unsigned long addr
)
1785 struct mempolicy
*mpol
;
1786 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1788 nodemask_t
*nodemask
;
1790 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1791 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1792 mpol_cond_put(mpol
);
1797 /* page migration callback function */
1798 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1800 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1801 struct page
*page
= NULL
;
1803 if (nid
!= NUMA_NO_NODE
)
1804 gfp_mask
|= __GFP_THISNODE
;
1806 spin_lock(&hugetlb_lock
);
1807 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1808 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1809 spin_unlock(&hugetlb_lock
);
1812 page
= alloc_migrate_huge_page(h
, gfp_mask
, nid
, NULL
);
1817 /* page migration callback function */
1818 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1821 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1823 spin_lock(&hugetlb_lock
);
1824 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1827 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1829 spin_unlock(&hugetlb_lock
);
1833 spin_unlock(&hugetlb_lock
);
1835 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1838 /* mempolicy aware migration callback */
1839 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
1840 unsigned long address
)
1842 struct mempolicy
*mpol
;
1843 nodemask_t
*nodemask
;
1848 gfp_mask
= htlb_alloc_mask(h
);
1849 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1850 page
= alloc_huge_page_nodemask(h
, node
, nodemask
);
1851 mpol_cond_put(mpol
);
1857 * Increase the hugetlb pool such that it can accommodate a reservation
1860 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1862 struct list_head surplus_list
;
1863 struct page
*page
, *tmp
;
1865 int needed
, allocated
;
1866 bool alloc_ok
= true;
1868 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1870 h
->resv_huge_pages
+= delta
;
1875 INIT_LIST_HEAD(&surplus_list
);
1879 spin_unlock(&hugetlb_lock
);
1880 for (i
= 0; i
< needed
; i
++) {
1881 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
1882 NUMA_NO_NODE
, NULL
);
1887 list_add(&page
->lru
, &surplus_list
);
1893 * After retaking hugetlb_lock, we need to recalculate 'needed'
1894 * because either resv_huge_pages or free_huge_pages may have changed.
1896 spin_lock(&hugetlb_lock
);
1897 needed
= (h
->resv_huge_pages
+ delta
) -
1898 (h
->free_huge_pages
+ allocated
);
1903 * We were not able to allocate enough pages to
1904 * satisfy the entire reservation so we free what
1905 * we've allocated so far.
1910 * The surplus_list now contains _at_least_ the number of extra pages
1911 * needed to accommodate the reservation. Add the appropriate number
1912 * of pages to the hugetlb pool and free the extras back to the buddy
1913 * allocator. Commit the entire reservation here to prevent another
1914 * process from stealing the pages as they are added to the pool but
1915 * before they are reserved.
1917 needed
+= allocated
;
1918 h
->resv_huge_pages
+= delta
;
1921 /* Free the needed pages to the hugetlb pool */
1922 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1926 * This page is now managed by the hugetlb allocator and has
1927 * no users -- drop the buddy allocator's reference.
1929 put_page_testzero(page
);
1930 VM_BUG_ON_PAGE(page_count(page
), page
);
1931 enqueue_huge_page(h
, page
);
1934 spin_unlock(&hugetlb_lock
);
1936 /* Free unnecessary surplus pages to the buddy allocator */
1937 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1939 spin_lock(&hugetlb_lock
);
1945 * This routine has two main purposes:
1946 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1947 * in unused_resv_pages. This corresponds to the prior adjustments made
1948 * to the associated reservation map.
1949 * 2) Free any unused surplus pages that may have been allocated to satisfy
1950 * the reservation. As many as unused_resv_pages may be freed.
1952 * Called with hugetlb_lock held. However, the lock could be dropped (and
1953 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1954 * we must make sure nobody else can claim pages we are in the process of
1955 * freeing. Do this by ensuring resv_huge_page always is greater than the
1956 * number of huge pages we plan to free when dropping the lock.
1958 static void return_unused_surplus_pages(struct hstate
*h
,
1959 unsigned long unused_resv_pages
)
1961 unsigned long nr_pages
;
1963 /* Cannot return gigantic pages currently */
1964 if (hstate_is_gigantic(h
))
1968 * Part (or even all) of the reservation could have been backed
1969 * by pre-allocated pages. Only free surplus pages.
1971 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1974 * We want to release as many surplus pages as possible, spread
1975 * evenly across all nodes with memory. Iterate across these nodes
1976 * until we can no longer free unreserved surplus pages. This occurs
1977 * when the nodes with surplus pages have no free pages.
1978 * free_pool_huge_page() will balance the the freed pages across the
1979 * on-line nodes with memory and will handle the hstate accounting.
1981 * Note that we decrement resv_huge_pages as we free the pages. If
1982 * we drop the lock, resv_huge_pages will still be sufficiently large
1983 * to cover subsequent pages we may free.
1985 while (nr_pages
--) {
1986 h
->resv_huge_pages
--;
1987 unused_resv_pages
--;
1988 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1990 cond_resched_lock(&hugetlb_lock
);
1994 /* Fully uncommit the reservation */
1995 h
->resv_huge_pages
-= unused_resv_pages
;
2000 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2001 * are used by the huge page allocation routines to manage reservations.
2003 * vma_needs_reservation is called to determine if the huge page at addr
2004 * within the vma has an associated reservation. If a reservation is
2005 * needed, the value 1 is returned. The caller is then responsible for
2006 * managing the global reservation and subpool usage counts. After
2007 * the huge page has been allocated, vma_commit_reservation is called
2008 * to add the page to the reservation map. If the page allocation fails,
2009 * the reservation must be ended instead of committed. vma_end_reservation
2010 * is called in such cases.
2012 * In the normal case, vma_commit_reservation returns the same value
2013 * as the preceding vma_needs_reservation call. The only time this
2014 * is not the case is if a reserve map was changed between calls. It
2015 * is the responsibility of the caller to notice the difference and
2016 * take appropriate action.
2018 * vma_add_reservation is used in error paths where a reservation must
2019 * be restored when a newly allocated huge page must be freed. It is
2020 * to be called after calling vma_needs_reservation to determine if a
2021 * reservation exists.
2023 enum vma_resv_mode
{
2029 static long __vma_reservation_common(struct hstate
*h
,
2030 struct vm_area_struct
*vma
, unsigned long addr
,
2031 enum vma_resv_mode mode
)
2033 struct resv_map
*resv
;
2037 resv
= vma_resv_map(vma
);
2041 idx
= vma_hugecache_offset(h
, vma
, addr
);
2043 case VMA_NEEDS_RESV
:
2044 ret
= region_chg(resv
, idx
, idx
+ 1);
2046 case VMA_COMMIT_RESV
:
2047 ret
= region_add(resv
, idx
, idx
+ 1);
2050 region_abort(resv
, idx
, idx
+ 1);
2054 if (vma
->vm_flags
& VM_MAYSHARE
)
2055 ret
= region_add(resv
, idx
, idx
+ 1);
2057 region_abort(resv
, idx
, idx
+ 1);
2058 ret
= region_del(resv
, idx
, idx
+ 1);
2065 if (vma
->vm_flags
& VM_MAYSHARE
)
2067 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
2069 * In most cases, reserves always exist for private mappings.
2070 * However, a file associated with mapping could have been
2071 * hole punched or truncated after reserves were consumed.
2072 * As subsequent fault on such a range will not use reserves.
2073 * Subtle - The reserve map for private mappings has the
2074 * opposite meaning than that of shared mappings. If NO
2075 * entry is in the reserve map, it means a reservation exists.
2076 * If an entry exists in the reserve map, it means the
2077 * reservation has already been consumed. As a result, the
2078 * return value of this routine is the opposite of the
2079 * value returned from reserve map manipulation routines above.
2087 return ret
< 0 ? ret
: 0;
2090 static long vma_needs_reservation(struct hstate
*h
,
2091 struct vm_area_struct
*vma
, unsigned long addr
)
2093 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
2096 static long vma_commit_reservation(struct hstate
*h
,
2097 struct vm_area_struct
*vma
, unsigned long addr
)
2099 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
2102 static void vma_end_reservation(struct hstate
*h
,
2103 struct vm_area_struct
*vma
, unsigned long addr
)
2105 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
2108 static long vma_add_reservation(struct hstate
*h
,
2109 struct vm_area_struct
*vma
, unsigned long addr
)
2111 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
2115 * This routine is called to restore a reservation on error paths. In the
2116 * specific error paths, a huge page was allocated (via alloc_huge_page)
2117 * and is about to be freed. If a reservation for the page existed,
2118 * alloc_huge_page would have consumed the reservation and set PagePrivate
2119 * in the newly allocated page. When the page is freed via free_huge_page,
2120 * the global reservation count will be incremented if PagePrivate is set.
2121 * However, free_huge_page can not adjust the reserve map. Adjust the
2122 * reserve map here to be consistent with global reserve count adjustments
2123 * to be made by free_huge_page.
2125 static void restore_reserve_on_error(struct hstate
*h
,
2126 struct vm_area_struct
*vma
, unsigned long address
,
2129 if (unlikely(PagePrivate(page
))) {
2130 long rc
= vma_needs_reservation(h
, vma
, address
);
2132 if (unlikely(rc
< 0)) {
2134 * Rare out of memory condition in reserve map
2135 * manipulation. Clear PagePrivate so that
2136 * global reserve count will not be incremented
2137 * by free_huge_page. This will make it appear
2138 * as though the reservation for this page was
2139 * consumed. This may prevent the task from
2140 * faulting in the page at a later time. This
2141 * is better than inconsistent global huge page
2142 * accounting of reserve counts.
2144 ClearPagePrivate(page
);
2146 rc
= vma_add_reservation(h
, vma
, address
);
2147 if (unlikely(rc
< 0))
2149 * See above comment about rare out of
2152 ClearPagePrivate(page
);
2154 vma_end_reservation(h
, vma
, address
);
2158 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2159 unsigned long addr
, int avoid_reserve
)
2161 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2162 struct hstate
*h
= hstate_vma(vma
);
2164 long map_chg
, map_commit
;
2167 struct hugetlb_cgroup
*h_cg
;
2169 idx
= hstate_index(h
);
2171 * Examine the region/reserve map to determine if the process
2172 * has a reservation for the page to be allocated. A return
2173 * code of zero indicates a reservation exists (no change).
2175 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2177 return ERR_PTR(-ENOMEM
);
2180 * Processes that did not create the mapping will have no
2181 * reserves as indicated by the region/reserve map. Check
2182 * that the allocation will not exceed the subpool limit.
2183 * Allocations for MAP_NORESERVE mappings also need to be
2184 * checked against any subpool limit.
2186 if (map_chg
|| avoid_reserve
) {
2187 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2189 vma_end_reservation(h
, vma
, addr
);
2190 return ERR_PTR(-ENOSPC
);
2194 * Even though there was no reservation in the region/reserve
2195 * map, there could be reservations associated with the
2196 * subpool that can be used. This would be indicated if the
2197 * return value of hugepage_subpool_get_pages() is zero.
2198 * However, if avoid_reserve is specified we still avoid even
2199 * the subpool reservations.
2205 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2207 goto out_subpool_put
;
2209 spin_lock(&hugetlb_lock
);
2211 * glb_chg is passed to indicate whether or not a page must be taken
2212 * from the global free pool (global change). gbl_chg == 0 indicates
2213 * a reservation exists for the allocation.
2215 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2217 spin_unlock(&hugetlb_lock
);
2218 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2220 goto out_uncharge_cgroup
;
2221 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2222 SetPagePrivate(page
);
2223 h
->resv_huge_pages
--;
2225 spin_lock(&hugetlb_lock
);
2226 list_move(&page
->lru
, &h
->hugepage_activelist
);
2229 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2230 spin_unlock(&hugetlb_lock
);
2232 set_page_private(page
, (unsigned long)spool
);
2234 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2235 if (unlikely(map_chg
> map_commit
)) {
2237 * The page was added to the reservation map between
2238 * vma_needs_reservation and vma_commit_reservation.
2239 * This indicates a race with hugetlb_reserve_pages.
2240 * Adjust for the subpool count incremented above AND
2241 * in hugetlb_reserve_pages for the same page. Also,
2242 * the reservation count added in hugetlb_reserve_pages
2243 * no longer applies.
2247 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2248 hugetlb_acct_memory(h
, -rsv_adjust
);
2252 out_uncharge_cgroup
:
2253 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2255 if (map_chg
|| avoid_reserve
)
2256 hugepage_subpool_put_pages(spool
, 1);
2257 vma_end_reservation(h
, vma
, addr
);
2258 return ERR_PTR(-ENOSPC
);
2261 int alloc_bootmem_huge_page(struct hstate
*h
)
2262 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2263 int __alloc_bootmem_huge_page(struct hstate
*h
)
2265 struct huge_bootmem_page
*m
;
2268 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2271 addr
= memblock_alloc_try_nid_raw(
2272 huge_page_size(h
), huge_page_size(h
),
2273 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2276 * Use the beginning of the huge page to store the
2277 * huge_bootmem_page struct (until gather_bootmem
2278 * puts them into the mem_map).
2287 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2288 /* Put them into a private list first because mem_map is not up yet */
2289 INIT_LIST_HEAD(&m
->list
);
2290 list_add(&m
->list
, &huge_boot_pages
);
2295 static void __init
prep_compound_huge_page(struct page
*page
,
2298 if (unlikely(order
> (MAX_ORDER
- 1)))
2299 prep_compound_gigantic_page(page
, order
);
2301 prep_compound_page(page
, order
);
2304 /* Put bootmem huge pages into the standard lists after mem_map is up */
2305 static void __init
gather_bootmem_prealloc(void)
2307 struct huge_bootmem_page
*m
;
2309 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2310 struct page
*page
= virt_to_page(m
);
2311 struct hstate
*h
= m
->hstate
;
2313 WARN_ON(page_count(page
) != 1);
2314 prep_compound_huge_page(page
, h
->order
);
2315 WARN_ON(PageReserved(page
));
2316 prep_new_huge_page(h
, page
, page_to_nid(page
));
2317 put_page(page
); /* free it into the hugepage allocator */
2320 * If we had gigantic hugepages allocated at boot time, we need
2321 * to restore the 'stolen' pages to totalram_pages in order to
2322 * fix confusing memory reports from free(1) and another
2323 * side-effects, like CommitLimit going negative.
2325 if (hstate_is_gigantic(h
))
2326 adjust_managed_page_count(page
, 1 << h
->order
);
2331 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2334 nodemask_t
*node_alloc_noretry
;
2336 if (!hstate_is_gigantic(h
)) {
2338 * Bit mask controlling how hard we retry per-node allocations.
2339 * Ignore errors as lower level routines can deal with
2340 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2341 * time, we are likely in bigger trouble.
2343 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2346 /* allocations done at boot time */
2347 node_alloc_noretry
= NULL
;
2350 /* bit mask controlling how hard we retry per-node allocations */
2351 if (node_alloc_noretry
)
2352 nodes_clear(*node_alloc_noretry
);
2354 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2355 if (hstate_is_gigantic(h
)) {
2356 if (!alloc_bootmem_huge_page(h
))
2358 } else if (!alloc_pool_huge_page(h
,
2359 &node_states
[N_MEMORY
],
2360 node_alloc_noretry
))
2364 if (i
< h
->max_huge_pages
) {
2367 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2368 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2369 h
->max_huge_pages
, buf
, i
);
2370 h
->max_huge_pages
= i
;
2373 kfree(node_alloc_noretry
);
2376 static void __init
hugetlb_init_hstates(void)
2380 for_each_hstate(h
) {
2381 if (minimum_order
> huge_page_order(h
))
2382 minimum_order
= huge_page_order(h
);
2384 /* oversize hugepages were init'ed in early boot */
2385 if (!hstate_is_gigantic(h
))
2386 hugetlb_hstate_alloc_pages(h
);
2388 VM_BUG_ON(minimum_order
== UINT_MAX
);
2391 static void __init
report_hugepages(void)
2395 for_each_hstate(h
) {
2398 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2399 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2400 buf
, h
->free_huge_pages
);
2404 #ifdef CONFIG_HIGHMEM
2405 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2406 nodemask_t
*nodes_allowed
)
2410 if (hstate_is_gigantic(h
))
2413 for_each_node_mask(i
, *nodes_allowed
) {
2414 struct page
*page
, *next
;
2415 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2416 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2417 if (count
>= h
->nr_huge_pages
)
2419 if (PageHighMem(page
))
2421 list_del(&page
->lru
);
2422 update_and_free_page(h
, page
);
2423 h
->free_huge_pages
--;
2424 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2429 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2430 nodemask_t
*nodes_allowed
)
2436 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2437 * balanced by operating on them in a round-robin fashion.
2438 * Returns 1 if an adjustment was made.
2440 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2445 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2448 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2449 if (h
->surplus_huge_pages_node
[node
])
2453 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2454 if (h
->surplus_huge_pages_node
[node
] <
2455 h
->nr_huge_pages_node
[node
])
2462 h
->surplus_huge_pages
+= delta
;
2463 h
->surplus_huge_pages_node
[node
] += delta
;
2467 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2468 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2469 nodemask_t
*nodes_allowed
)
2471 unsigned long min_count
, ret
;
2472 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2475 * Bit mask controlling how hard we retry per-node allocations.
2476 * If we can not allocate the bit mask, do not attempt to allocate
2477 * the requested huge pages.
2479 if (node_alloc_noretry
)
2480 nodes_clear(*node_alloc_noretry
);
2484 spin_lock(&hugetlb_lock
);
2487 * Check for a node specific request.
2488 * Changing node specific huge page count may require a corresponding
2489 * change to the global count. In any case, the passed node mask
2490 * (nodes_allowed) will restrict alloc/free to the specified node.
2492 if (nid
!= NUMA_NO_NODE
) {
2493 unsigned long old_count
= count
;
2495 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2497 * User may have specified a large count value which caused the
2498 * above calculation to overflow. In this case, they wanted
2499 * to allocate as many huge pages as possible. Set count to
2500 * largest possible value to align with their intention.
2502 if (count
< old_count
)
2507 * Gigantic pages runtime allocation depend on the capability for large
2508 * page range allocation.
2509 * If the system does not provide this feature, return an error when
2510 * the user tries to allocate gigantic pages but let the user free the
2511 * boottime allocated gigantic pages.
2513 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2514 if (count
> persistent_huge_pages(h
)) {
2515 spin_unlock(&hugetlb_lock
);
2516 NODEMASK_FREE(node_alloc_noretry
);
2519 /* Fall through to decrease pool */
2523 * Increase the pool size
2524 * First take pages out of surplus state. Then make up the
2525 * remaining difference by allocating fresh huge pages.
2527 * We might race with alloc_surplus_huge_page() here and be unable
2528 * to convert a surplus huge page to a normal huge page. That is
2529 * not critical, though, it just means the overall size of the
2530 * pool might be one hugepage larger than it needs to be, but
2531 * within all the constraints specified by the sysctls.
2533 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2534 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2538 while (count
> persistent_huge_pages(h
)) {
2540 * If this allocation races such that we no longer need the
2541 * page, free_huge_page will handle it by freeing the page
2542 * and reducing the surplus.
2544 spin_unlock(&hugetlb_lock
);
2546 /* yield cpu to avoid soft lockup */
2549 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2550 node_alloc_noretry
);
2551 spin_lock(&hugetlb_lock
);
2555 /* Bail for signals. Probably ctrl-c from user */
2556 if (signal_pending(current
))
2561 * Decrease the pool size
2562 * First return free pages to the buddy allocator (being careful
2563 * to keep enough around to satisfy reservations). Then place
2564 * pages into surplus state as needed so the pool will shrink
2565 * to the desired size as pages become free.
2567 * By placing pages into the surplus state independent of the
2568 * overcommit value, we are allowing the surplus pool size to
2569 * exceed overcommit. There are few sane options here. Since
2570 * alloc_surplus_huge_page() is checking the global counter,
2571 * though, we'll note that we're not allowed to exceed surplus
2572 * and won't grow the pool anywhere else. Not until one of the
2573 * sysctls are changed, or the surplus pages go out of use.
2575 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2576 min_count
= max(count
, min_count
);
2577 try_to_free_low(h
, min_count
, nodes_allowed
);
2578 while (min_count
< persistent_huge_pages(h
)) {
2579 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2581 cond_resched_lock(&hugetlb_lock
);
2583 while (count
< persistent_huge_pages(h
)) {
2584 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2588 h
->max_huge_pages
= persistent_huge_pages(h
);
2589 spin_unlock(&hugetlb_lock
);
2591 NODEMASK_FREE(node_alloc_noretry
);
2596 #define HSTATE_ATTR_RO(_name) \
2597 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2599 #define HSTATE_ATTR(_name) \
2600 static struct kobj_attribute _name##_attr = \
2601 __ATTR(_name, 0644, _name##_show, _name##_store)
2603 static struct kobject
*hugepages_kobj
;
2604 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2606 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2608 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2612 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2613 if (hstate_kobjs
[i
] == kobj
) {
2615 *nidp
= NUMA_NO_NODE
;
2619 return kobj_to_node_hstate(kobj
, nidp
);
2622 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2623 struct kobj_attribute
*attr
, char *buf
)
2626 unsigned long nr_huge_pages
;
2629 h
= kobj_to_hstate(kobj
, &nid
);
2630 if (nid
== NUMA_NO_NODE
)
2631 nr_huge_pages
= h
->nr_huge_pages
;
2633 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2635 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2638 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2639 struct hstate
*h
, int nid
,
2640 unsigned long count
, size_t len
)
2643 nodemask_t nodes_allowed
, *n_mask
;
2645 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2648 if (nid
== NUMA_NO_NODE
) {
2650 * global hstate attribute
2652 if (!(obey_mempolicy
&&
2653 init_nodemask_of_mempolicy(&nodes_allowed
)))
2654 n_mask
= &node_states
[N_MEMORY
];
2656 n_mask
= &nodes_allowed
;
2659 * Node specific request. count adjustment happens in
2660 * set_max_huge_pages() after acquiring hugetlb_lock.
2662 init_nodemask_of_node(&nodes_allowed
, nid
);
2663 n_mask
= &nodes_allowed
;
2666 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2668 return err
? err
: len
;
2671 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2672 struct kobject
*kobj
, const char *buf
,
2676 unsigned long count
;
2680 err
= kstrtoul(buf
, 10, &count
);
2684 h
= kobj_to_hstate(kobj
, &nid
);
2685 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2688 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2689 struct kobj_attribute
*attr
, char *buf
)
2691 return nr_hugepages_show_common(kobj
, attr
, buf
);
2694 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2695 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2697 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2699 HSTATE_ATTR(nr_hugepages
);
2704 * hstate attribute for optionally mempolicy-based constraint on persistent
2705 * huge page alloc/free.
2707 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2708 struct kobj_attribute
*attr
, char *buf
)
2710 return nr_hugepages_show_common(kobj
, attr
, buf
);
2713 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2714 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2716 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2718 HSTATE_ATTR(nr_hugepages_mempolicy
);
2722 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2723 struct kobj_attribute
*attr
, char *buf
)
2725 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2726 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2729 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2730 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2733 unsigned long input
;
2734 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2736 if (hstate_is_gigantic(h
))
2739 err
= kstrtoul(buf
, 10, &input
);
2743 spin_lock(&hugetlb_lock
);
2744 h
->nr_overcommit_huge_pages
= input
;
2745 spin_unlock(&hugetlb_lock
);
2749 HSTATE_ATTR(nr_overcommit_hugepages
);
2751 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2752 struct kobj_attribute
*attr
, char *buf
)
2755 unsigned long free_huge_pages
;
2758 h
= kobj_to_hstate(kobj
, &nid
);
2759 if (nid
== NUMA_NO_NODE
)
2760 free_huge_pages
= h
->free_huge_pages
;
2762 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2764 return sprintf(buf
, "%lu\n", free_huge_pages
);
2766 HSTATE_ATTR_RO(free_hugepages
);
2768 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2769 struct kobj_attribute
*attr
, char *buf
)
2771 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2772 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2774 HSTATE_ATTR_RO(resv_hugepages
);
2776 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2777 struct kobj_attribute
*attr
, char *buf
)
2780 unsigned long surplus_huge_pages
;
2783 h
= kobj_to_hstate(kobj
, &nid
);
2784 if (nid
== NUMA_NO_NODE
)
2785 surplus_huge_pages
= h
->surplus_huge_pages
;
2787 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2789 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2791 HSTATE_ATTR_RO(surplus_hugepages
);
2793 static struct attribute
*hstate_attrs
[] = {
2794 &nr_hugepages_attr
.attr
,
2795 &nr_overcommit_hugepages_attr
.attr
,
2796 &free_hugepages_attr
.attr
,
2797 &resv_hugepages_attr
.attr
,
2798 &surplus_hugepages_attr
.attr
,
2800 &nr_hugepages_mempolicy_attr
.attr
,
2805 static const struct attribute_group hstate_attr_group
= {
2806 .attrs
= hstate_attrs
,
2809 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2810 struct kobject
**hstate_kobjs
,
2811 const struct attribute_group
*hstate_attr_group
)
2814 int hi
= hstate_index(h
);
2816 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2817 if (!hstate_kobjs
[hi
])
2820 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2822 kobject_put(hstate_kobjs
[hi
]);
2823 hstate_kobjs
[hi
] = NULL
;
2829 static void __init
hugetlb_sysfs_init(void)
2834 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2835 if (!hugepages_kobj
)
2838 for_each_hstate(h
) {
2839 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2840 hstate_kobjs
, &hstate_attr_group
);
2842 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2849 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2850 * with node devices in node_devices[] using a parallel array. The array
2851 * index of a node device or _hstate == node id.
2852 * This is here to avoid any static dependency of the node device driver, in
2853 * the base kernel, on the hugetlb module.
2855 struct node_hstate
{
2856 struct kobject
*hugepages_kobj
;
2857 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2859 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2862 * A subset of global hstate attributes for node devices
2864 static struct attribute
*per_node_hstate_attrs
[] = {
2865 &nr_hugepages_attr
.attr
,
2866 &free_hugepages_attr
.attr
,
2867 &surplus_hugepages_attr
.attr
,
2871 static const struct attribute_group per_node_hstate_attr_group
= {
2872 .attrs
= per_node_hstate_attrs
,
2876 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2877 * Returns node id via non-NULL nidp.
2879 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2883 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2884 struct node_hstate
*nhs
= &node_hstates
[nid
];
2886 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2887 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2899 * Unregister hstate attributes from a single node device.
2900 * No-op if no hstate attributes attached.
2902 static void hugetlb_unregister_node(struct node
*node
)
2905 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2907 if (!nhs
->hugepages_kobj
)
2908 return; /* no hstate attributes */
2910 for_each_hstate(h
) {
2911 int idx
= hstate_index(h
);
2912 if (nhs
->hstate_kobjs
[idx
]) {
2913 kobject_put(nhs
->hstate_kobjs
[idx
]);
2914 nhs
->hstate_kobjs
[idx
] = NULL
;
2918 kobject_put(nhs
->hugepages_kobj
);
2919 nhs
->hugepages_kobj
= NULL
;
2924 * Register hstate attributes for a single node device.
2925 * No-op if attributes already registered.
2927 static void hugetlb_register_node(struct node
*node
)
2930 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2933 if (nhs
->hugepages_kobj
)
2934 return; /* already allocated */
2936 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2938 if (!nhs
->hugepages_kobj
)
2941 for_each_hstate(h
) {
2942 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2944 &per_node_hstate_attr_group
);
2946 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2947 h
->name
, node
->dev
.id
);
2948 hugetlb_unregister_node(node
);
2955 * hugetlb init time: register hstate attributes for all registered node
2956 * devices of nodes that have memory. All on-line nodes should have
2957 * registered their associated device by this time.
2959 static void __init
hugetlb_register_all_nodes(void)
2963 for_each_node_state(nid
, N_MEMORY
) {
2964 struct node
*node
= node_devices
[nid
];
2965 if (node
->dev
.id
== nid
)
2966 hugetlb_register_node(node
);
2970 * Let the node device driver know we're here so it can
2971 * [un]register hstate attributes on node hotplug.
2973 register_hugetlbfs_with_node(hugetlb_register_node
,
2974 hugetlb_unregister_node
);
2976 #else /* !CONFIG_NUMA */
2978 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2986 static void hugetlb_register_all_nodes(void) { }
2990 static int __init
hugetlb_init(void)
2994 if (!hugepages_supported())
2997 if (!size_to_hstate(default_hstate_size
)) {
2998 if (default_hstate_size
!= 0) {
2999 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
3000 default_hstate_size
, HPAGE_SIZE
);
3003 default_hstate_size
= HPAGE_SIZE
;
3004 if (!size_to_hstate(default_hstate_size
))
3005 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
3007 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
3008 if (default_hstate_max_huge_pages
) {
3009 if (!default_hstate
.max_huge_pages
)
3010 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
3013 hugetlb_init_hstates();
3014 gather_bootmem_prealloc();
3017 hugetlb_sysfs_init();
3018 hugetlb_register_all_nodes();
3019 hugetlb_cgroup_file_init();
3022 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
3024 num_fault_mutexes
= 1;
3026 hugetlb_fault_mutex_table
=
3027 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
3029 BUG_ON(!hugetlb_fault_mutex_table
);
3031 for (i
= 0; i
< num_fault_mutexes
; i
++)
3032 mutex_init(&hugetlb_fault_mutex_table
[i
]);
3035 subsys_initcall(hugetlb_init
);
3037 /* Should be called on processing a hugepagesz=... option */
3038 void __init
hugetlb_bad_size(void)
3040 parsed_valid_hugepagesz
= false;
3043 void __init
hugetlb_add_hstate(unsigned int order
)
3048 if (size_to_hstate(PAGE_SIZE
<< order
)) {
3049 pr_warn("hugepagesz= specified twice, ignoring\n");
3052 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
3054 h
= &hstates
[hugetlb_max_hstate
++];
3056 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
3057 h
->nr_huge_pages
= 0;
3058 h
->free_huge_pages
= 0;
3059 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
3060 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
3061 INIT_LIST_HEAD(&h
->hugepage_activelist
);
3062 h
->next_nid_to_alloc
= first_memory_node
;
3063 h
->next_nid_to_free
= first_memory_node
;
3064 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
3065 huge_page_size(h
)/1024);
3070 static int __init
hugetlb_nrpages_setup(char *s
)
3073 static unsigned long *last_mhp
;
3075 if (!parsed_valid_hugepagesz
) {
3076 pr_warn("hugepages = %s preceded by "
3077 "an unsupported hugepagesz, ignoring\n", s
);
3078 parsed_valid_hugepagesz
= true;
3082 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
3083 * so this hugepages= parameter goes to the "default hstate".
3085 else if (!hugetlb_max_hstate
)
3086 mhp
= &default_hstate_max_huge_pages
;
3088 mhp
= &parsed_hstate
->max_huge_pages
;
3090 if (mhp
== last_mhp
) {
3091 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
3095 if (sscanf(s
, "%lu", mhp
) <= 0)
3099 * Global state is always initialized later in hugetlb_init.
3100 * But we need to allocate >= MAX_ORDER hstates here early to still
3101 * use the bootmem allocator.
3103 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
3104 hugetlb_hstate_alloc_pages(parsed_hstate
);
3110 __setup("hugepages=", hugetlb_nrpages_setup
);
3112 static int __init
hugetlb_default_setup(char *s
)
3114 default_hstate_size
= memparse(s
, &s
);
3117 __setup("default_hugepagesz=", hugetlb_default_setup
);
3119 static unsigned int cpuset_mems_nr(unsigned int *array
)
3122 unsigned int nr
= 0;
3124 for_each_node_mask(node
, cpuset_current_mems_allowed
)
3130 #ifdef CONFIG_SYSCTL
3131 static int proc_hugetlb_doulongvec_minmax(struct ctl_table
*table
, int write
,
3132 void *buffer
, size_t *length
,
3133 loff_t
*ppos
, unsigned long *out
)
3135 struct ctl_table dup_table
;
3138 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3139 * can duplicate the @table and alter the duplicate of it.
3142 dup_table
.data
= out
;
3144 return proc_doulongvec_minmax(&dup_table
, write
, buffer
, length
, ppos
);
3147 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
3148 struct ctl_table
*table
, int write
,
3149 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3151 struct hstate
*h
= &default_hstate
;
3152 unsigned long tmp
= h
->max_huge_pages
;
3155 if (!hugepages_supported())
3158 ret
= proc_hugetlb_doulongvec_minmax(table
, write
, buffer
, length
, ppos
,
3164 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
3165 NUMA_NO_NODE
, tmp
, *length
);
3170 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
3171 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3174 return hugetlb_sysctl_handler_common(false, table
, write
,
3175 buffer
, length
, ppos
);
3179 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3180 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3182 return hugetlb_sysctl_handler_common(true, table
, write
,
3183 buffer
, length
, ppos
);
3185 #endif /* CONFIG_NUMA */
3187 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3188 void __user
*buffer
,
3189 size_t *length
, loff_t
*ppos
)
3191 struct hstate
*h
= &default_hstate
;
3195 if (!hugepages_supported())
3198 tmp
= h
->nr_overcommit_huge_pages
;
3200 if (write
&& hstate_is_gigantic(h
))
3203 ret
= proc_hugetlb_doulongvec_minmax(table
, write
, buffer
, length
, ppos
,
3209 spin_lock(&hugetlb_lock
);
3210 h
->nr_overcommit_huge_pages
= tmp
;
3211 spin_unlock(&hugetlb_lock
);
3217 #endif /* CONFIG_SYSCTL */
3219 void hugetlb_report_meminfo(struct seq_file
*m
)
3222 unsigned long total
= 0;
3224 if (!hugepages_supported())
3227 for_each_hstate(h
) {
3228 unsigned long count
= h
->nr_huge_pages
;
3230 total
+= (PAGE_SIZE
<< huge_page_order(h
)) * count
;
3232 if (h
== &default_hstate
)
3234 "HugePages_Total: %5lu\n"
3235 "HugePages_Free: %5lu\n"
3236 "HugePages_Rsvd: %5lu\n"
3237 "HugePages_Surp: %5lu\n"
3238 "Hugepagesize: %8lu kB\n",
3242 h
->surplus_huge_pages
,
3243 (PAGE_SIZE
<< huge_page_order(h
)) / 1024);
3246 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ 1024);
3249 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3251 struct hstate
*h
= &default_hstate
;
3252 if (!hugepages_supported())
3255 "Node %d HugePages_Total: %5u\n"
3256 "Node %d HugePages_Free: %5u\n"
3257 "Node %d HugePages_Surp: %5u\n",
3258 nid
, h
->nr_huge_pages_node
[nid
],
3259 nid
, h
->free_huge_pages_node
[nid
],
3260 nid
, h
->surplus_huge_pages_node
[nid
]);
3263 void hugetlb_show_meminfo(void)
3268 if (!hugepages_supported())
3271 for_each_node_state(nid
, N_MEMORY
)
3273 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3275 h
->nr_huge_pages_node
[nid
],
3276 h
->free_huge_pages_node
[nid
],
3277 h
->surplus_huge_pages_node
[nid
],
3278 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3281 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3283 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3284 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3287 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3288 unsigned long hugetlb_total_pages(void)
3291 unsigned long nr_total_pages
= 0;
3294 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3295 return nr_total_pages
;
3298 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3302 spin_lock(&hugetlb_lock
);
3304 * When cpuset is configured, it breaks the strict hugetlb page
3305 * reservation as the accounting is done on a global variable. Such
3306 * reservation is completely rubbish in the presence of cpuset because
3307 * the reservation is not checked against page availability for the
3308 * current cpuset. Application can still potentially OOM'ed by kernel
3309 * with lack of free htlb page in cpuset that the task is in.
3310 * Attempt to enforce strict accounting with cpuset is almost
3311 * impossible (or too ugly) because cpuset is too fluid that
3312 * task or memory node can be dynamically moved between cpusets.
3314 * The change of semantics for shared hugetlb mapping with cpuset is
3315 * undesirable. However, in order to preserve some of the semantics,
3316 * we fall back to check against current free page availability as
3317 * a best attempt and hopefully to minimize the impact of changing
3318 * semantics that cpuset has.
3321 if (gather_surplus_pages(h
, delta
) < 0)
3324 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3325 return_unused_surplus_pages(h
, delta
);
3332 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3335 spin_unlock(&hugetlb_lock
);
3339 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3341 struct resv_map
*resv
= vma_resv_map(vma
);
3344 * This new VMA should share its siblings reservation map if present.
3345 * The VMA will only ever have a valid reservation map pointer where
3346 * it is being copied for another still existing VMA. As that VMA
3347 * has a reference to the reservation map it cannot disappear until
3348 * after this open call completes. It is therefore safe to take a
3349 * new reference here without additional locking.
3351 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3352 kref_get(&resv
->refs
);
3355 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3357 struct hstate
*h
= hstate_vma(vma
);
3358 struct resv_map
*resv
= vma_resv_map(vma
);
3359 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3360 unsigned long reserve
, start
, end
;
3363 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3366 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3367 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3369 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3371 kref_put(&resv
->refs
, resv_map_release
);
3375 * Decrement reserve counts. The global reserve count may be
3376 * adjusted if the subpool has a minimum size.
3378 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3379 hugetlb_acct_memory(h
, -gbl_reserve
);
3383 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3385 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3390 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3392 struct hstate
*hstate
= hstate_vma(vma
);
3394 return 1UL << huge_page_shift(hstate
);
3398 * We cannot handle pagefaults against hugetlb pages at all. They cause
3399 * handle_mm_fault() to try to instantiate regular-sized pages in the
3400 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3403 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3410 * When a new function is introduced to vm_operations_struct and added
3411 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3412 * This is because under System V memory model, mappings created via
3413 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3414 * their original vm_ops are overwritten with shm_vm_ops.
3416 const struct vm_operations_struct hugetlb_vm_ops
= {
3417 .fault
= hugetlb_vm_op_fault
,
3418 .open
= hugetlb_vm_op_open
,
3419 .close
= hugetlb_vm_op_close
,
3420 .split
= hugetlb_vm_op_split
,
3421 .pagesize
= hugetlb_vm_op_pagesize
,
3424 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3430 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3431 vma
->vm_page_prot
)));
3433 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3434 vma
->vm_page_prot
));
3436 entry
= pte_mkyoung(entry
);
3437 entry
= pte_mkhuge(entry
);
3438 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3443 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3444 unsigned long address
, pte_t
*ptep
)
3448 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3449 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3450 update_mmu_cache(vma
, address
, ptep
);
3453 bool is_hugetlb_entry_migration(pte_t pte
)
3457 if (huge_pte_none(pte
) || pte_present(pte
))
3459 swp
= pte_to_swp_entry(pte
);
3460 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3466 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3470 if (huge_pte_none(pte
) || pte_present(pte
))
3472 swp
= pte_to_swp_entry(pte
);
3473 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3479 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3480 struct vm_area_struct
*vma
)
3482 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3483 struct page
*ptepage
;
3486 struct hstate
*h
= hstate_vma(vma
);
3487 unsigned long sz
= huge_page_size(h
);
3488 struct mmu_notifier_range range
;
3491 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3494 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3497 mmu_notifier_invalidate_range_start(&range
);
3500 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3501 spinlock_t
*src_ptl
, *dst_ptl
;
3502 src_pte
= huge_pte_offset(src
, addr
, sz
);
3505 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3512 * If the pagetables are shared don't copy or take references.
3513 * dst_pte == src_pte is the common case of src/dest sharing.
3515 * However, src could have 'unshared' and dst shares with
3516 * another vma. If dst_pte !none, this implies sharing.
3517 * Check here before taking page table lock, and once again
3518 * after taking the lock below.
3520 dst_entry
= huge_ptep_get(dst_pte
);
3521 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3524 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3525 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3526 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3527 entry
= huge_ptep_get(src_pte
);
3528 dst_entry
= huge_ptep_get(dst_pte
);
3529 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3531 * Skip if src entry none. Also, skip in the
3532 * unlikely case dst entry !none as this implies
3533 * sharing with another vma.
3536 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3537 is_hugetlb_entry_hwpoisoned(entry
))) {
3538 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3540 if (is_write_migration_entry(swp_entry
) && cow
) {
3542 * COW mappings require pages in both
3543 * parent and child to be set to read.
3545 make_migration_entry_read(&swp_entry
);
3546 entry
= swp_entry_to_pte(swp_entry
);
3547 set_huge_swap_pte_at(src
, addr
, src_pte
,
3550 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3554 * No need to notify as we are downgrading page
3555 * table protection not changing it to point
3558 * See Documentation/vm/mmu_notifier.rst
3560 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3562 entry
= huge_ptep_get(src_pte
);
3563 ptepage
= pte_page(entry
);
3565 page_dup_rmap(ptepage
, true);
3566 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3567 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3569 spin_unlock(src_ptl
);
3570 spin_unlock(dst_ptl
);
3574 mmu_notifier_invalidate_range_end(&range
);
3579 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3580 unsigned long start
, unsigned long end
,
3581 struct page
*ref_page
)
3583 struct mm_struct
*mm
= vma
->vm_mm
;
3584 unsigned long address
;
3589 struct hstate
*h
= hstate_vma(vma
);
3590 unsigned long sz
= huge_page_size(h
);
3591 struct mmu_notifier_range range
;
3592 bool force_flush
= false;
3594 WARN_ON(!is_vm_hugetlb_page(vma
));
3595 BUG_ON(start
& ~huge_page_mask(h
));
3596 BUG_ON(end
& ~huge_page_mask(h
));
3599 * This is a hugetlb vma, all the pte entries should point
3602 tlb_change_page_size(tlb
, sz
);
3603 tlb_start_vma(tlb
, vma
);
3606 * If sharing possible, alert mmu notifiers of worst case.
3608 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3610 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3611 mmu_notifier_invalidate_range_start(&range
);
3613 for (; address
< end
; address
+= sz
) {
3614 ptep
= huge_pte_offset(mm
, address
, sz
);
3618 ptl
= huge_pte_lock(h
, mm
, ptep
);
3619 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3621 tlb_flush_pmd_range(tlb
, address
& PUD_MASK
, PUD_SIZE
);
3626 pte
= huge_ptep_get(ptep
);
3627 if (huge_pte_none(pte
)) {
3633 * Migrating hugepage or HWPoisoned hugepage is already
3634 * unmapped and its refcount is dropped, so just clear pte here.
3636 if (unlikely(!pte_present(pte
))) {
3637 huge_pte_clear(mm
, address
, ptep
, sz
);
3642 page
= pte_page(pte
);
3644 * If a reference page is supplied, it is because a specific
3645 * page is being unmapped, not a range. Ensure the page we
3646 * are about to unmap is the actual page of interest.
3649 if (page
!= ref_page
) {
3654 * Mark the VMA as having unmapped its page so that
3655 * future faults in this VMA will fail rather than
3656 * looking like data was lost
3658 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3661 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3662 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3663 if (huge_pte_dirty(pte
))
3664 set_page_dirty(page
);
3666 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3667 page_remove_rmap(page
, true);
3670 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3672 * Bail out after unmapping reference page if supplied
3677 mmu_notifier_invalidate_range_end(&range
);
3678 tlb_end_vma(tlb
, vma
);
3681 * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We
3682 * could defer the flush until now, since by holding i_mmap_rwsem we
3683 * guaranteed that the last refernece would not be dropped. But we must
3684 * do the flushing before we return, as otherwise i_mmap_rwsem will be
3685 * dropped and the last reference to the shared PMDs page might be
3688 * In theory we could defer the freeing of the PMD pages as well, but
3689 * huge_pmd_unshare() relies on the exact page_count for the PMD page to
3690 * detect sharing, so we cannot defer the release of the page either.
3691 * Instead, do flush now.
3694 tlb_flush_mmu_tlbonly(tlb
);
3697 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3698 struct vm_area_struct
*vma
, unsigned long start
,
3699 unsigned long end
, struct page
*ref_page
)
3701 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3704 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3705 * test will fail on a vma being torn down, and not grab a page table
3706 * on its way out. We're lucky that the flag has such an appropriate
3707 * name, and can in fact be safely cleared here. We could clear it
3708 * before the __unmap_hugepage_range above, but all that's necessary
3709 * is to clear it before releasing the i_mmap_rwsem. This works
3710 * because in the context this is called, the VMA is about to be
3711 * destroyed and the i_mmap_rwsem is held.
3713 vma
->vm_flags
&= ~VM_MAYSHARE
;
3716 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3717 unsigned long end
, struct page
*ref_page
)
3719 struct mm_struct
*mm
;
3720 struct mmu_gather tlb
;
3721 unsigned long tlb_start
= start
;
3722 unsigned long tlb_end
= end
;
3725 * If shared PMDs were possibly used within this vma range, adjust
3726 * start/end for worst case tlb flushing.
3727 * Note that we can not be sure if PMDs are shared until we try to
3728 * unmap pages. However, we want to make sure TLB flushing covers
3729 * the largest possible range.
3731 adjust_range_if_pmd_sharing_possible(vma
, &tlb_start
, &tlb_end
);
3735 tlb_gather_mmu(&tlb
, mm
, tlb_start
, tlb_end
);
3736 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3737 tlb_finish_mmu(&tlb
, tlb_start
, tlb_end
);
3741 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3742 * mappping it owns the reserve page for. The intention is to unmap the page
3743 * from other VMAs and let the children be SIGKILLed if they are faulting the
3746 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3747 struct page
*page
, unsigned long address
)
3749 struct hstate
*h
= hstate_vma(vma
);
3750 struct vm_area_struct
*iter_vma
;
3751 struct address_space
*mapping
;
3755 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3756 * from page cache lookup which is in HPAGE_SIZE units.
3758 address
= address
& huge_page_mask(h
);
3759 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3761 mapping
= vma
->vm_file
->f_mapping
;
3764 * Take the mapping lock for the duration of the table walk. As
3765 * this mapping should be shared between all the VMAs,
3766 * __unmap_hugepage_range() is called as the lock is already held
3768 i_mmap_lock_write(mapping
);
3769 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3770 /* Do not unmap the current VMA */
3771 if (iter_vma
== vma
)
3775 * Shared VMAs have their own reserves and do not affect
3776 * MAP_PRIVATE accounting but it is possible that a shared
3777 * VMA is using the same page so check and skip such VMAs.
3779 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3783 * Unmap the page from other VMAs without their own reserves.
3784 * They get marked to be SIGKILLed if they fault in these
3785 * areas. This is because a future no-page fault on this VMA
3786 * could insert a zeroed page instead of the data existing
3787 * from the time of fork. This would look like data corruption
3789 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3790 unmap_hugepage_range(iter_vma
, address
,
3791 address
+ huge_page_size(h
), page
);
3793 i_mmap_unlock_write(mapping
);
3797 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3798 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3799 * cannot race with other handlers or page migration.
3800 * Keep the pte_same checks anyway to make transition from the mutex easier.
3802 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3803 unsigned long address
, pte_t
*ptep
,
3804 struct page
*pagecache_page
, spinlock_t
*ptl
)
3807 struct hstate
*h
= hstate_vma(vma
);
3808 struct page
*old_page
, *new_page
;
3809 int outside_reserve
= 0;
3811 unsigned long haddr
= address
& huge_page_mask(h
);
3812 struct mmu_notifier_range range
;
3814 pte
= huge_ptep_get(ptep
);
3815 old_page
= pte_page(pte
);
3818 /* If no-one else is actually using this page, avoid the copy
3819 * and just make the page writable */
3820 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3821 page_move_anon_rmap(old_page
, vma
);
3822 set_huge_ptep_writable(vma
, haddr
, ptep
);
3827 * If the process that created a MAP_PRIVATE mapping is about to
3828 * perform a COW due to a shared page count, attempt to satisfy
3829 * the allocation without using the existing reserves. The pagecache
3830 * page is used to determine if the reserve at this address was
3831 * consumed or not. If reserves were used, a partial faulted mapping
3832 * at the time of fork() could consume its reserves on COW instead
3833 * of the full address range.
3835 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3836 old_page
!= pagecache_page
)
3837 outside_reserve
= 1;
3842 * Drop page table lock as buddy allocator may be called. It will
3843 * be acquired again before returning to the caller, as expected.
3846 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
3848 if (IS_ERR(new_page
)) {
3850 * If a process owning a MAP_PRIVATE mapping fails to COW,
3851 * it is due to references held by a child and an insufficient
3852 * huge page pool. To guarantee the original mappers
3853 * reliability, unmap the page from child processes. The child
3854 * may get SIGKILLed if it later faults.
3856 if (outside_reserve
) {
3858 BUG_ON(huge_pte_none(pte
));
3859 unmap_ref_private(mm
, vma
, old_page
, haddr
);
3860 BUG_ON(huge_pte_none(pte
));
3862 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3864 pte_same(huge_ptep_get(ptep
), pte
)))
3865 goto retry_avoidcopy
;
3867 * race occurs while re-acquiring page table
3868 * lock, and our job is done.
3873 ret
= vmf_error(PTR_ERR(new_page
));
3874 goto out_release_old
;
3878 * When the original hugepage is shared one, it does not have
3879 * anon_vma prepared.
3881 if (unlikely(anon_vma_prepare(vma
))) {
3883 goto out_release_all
;
3886 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3887 pages_per_huge_page(h
));
3888 __SetPageUptodate(new_page
);
3890 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
3891 haddr
+ huge_page_size(h
));
3892 mmu_notifier_invalidate_range_start(&range
);
3895 * Retake the page table lock to check for racing updates
3896 * before the page tables are altered
3899 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3900 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3901 ClearPagePrivate(new_page
);
3904 huge_ptep_clear_flush(vma
, haddr
, ptep
);
3905 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
3906 set_huge_pte_at(mm
, haddr
, ptep
,
3907 make_huge_pte(vma
, new_page
, 1));
3908 page_remove_rmap(old_page
, true);
3909 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
3910 set_page_huge_active(new_page
);
3911 /* Make the old page be freed below */
3912 new_page
= old_page
;
3915 mmu_notifier_invalidate_range_end(&range
);
3917 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
3922 spin_lock(ptl
); /* Caller expects lock to be held */
3926 /* Return the pagecache page at a given address within a VMA */
3927 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3928 struct vm_area_struct
*vma
, unsigned long address
)
3930 struct address_space
*mapping
;
3933 mapping
= vma
->vm_file
->f_mapping
;
3934 idx
= vma_hugecache_offset(h
, vma
, address
);
3936 return find_lock_page(mapping
, idx
);
3940 * Return whether there is a pagecache page to back given address within VMA.
3941 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3943 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3944 struct vm_area_struct
*vma
, unsigned long address
)
3946 struct address_space
*mapping
;
3950 mapping
= vma
->vm_file
->f_mapping
;
3951 idx
= vma_hugecache_offset(h
, vma
, address
);
3953 page
= find_get_page(mapping
, idx
);
3956 return page
!= NULL
;
3959 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3962 struct inode
*inode
= mapping
->host
;
3963 struct hstate
*h
= hstate_inode(inode
);
3964 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3968 ClearPagePrivate(page
);
3971 * set page dirty so that it will not be removed from cache/file
3972 * by non-hugetlbfs specific code paths.
3974 set_page_dirty(page
);
3976 spin_lock(&inode
->i_lock
);
3977 inode
->i_blocks
+= blocks_per_huge_page(h
);
3978 spin_unlock(&inode
->i_lock
);
3982 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
3983 struct vm_area_struct
*vma
,
3984 struct address_space
*mapping
, pgoff_t idx
,
3985 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3987 struct hstate
*h
= hstate_vma(vma
);
3988 vm_fault_t ret
= VM_FAULT_SIGBUS
;
3994 unsigned long haddr
= address
& huge_page_mask(h
);
3995 bool new_page
= false;
3998 * Currently, we are forced to kill the process in the event the
3999 * original mapper has unmapped pages from the child due to a failed
4000 * COW. Warn that such a situation has occurred as it may not be obvious
4002 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
4003 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4009 * Use page lock to guard against racing truncation
4010 * before we get page_table_lock.
4013 page
= find_lock_page(mapping
, idx
);
4015 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4020 * Check for page in userfault range
4022 if (userfaultfd_missing(vma
)) {
4024 struct vm_fault vmf
= {
4029 * Hard to debug if it ends up being
4030 * used by a callee that assumes
4031 * something about the other
4032 * uninitialized fields... same as in
4038 * hugetlb_fault_mutex must be dropped before
4039 * handling userfault. Reacquire after handling
4040 * fault to make calling code simpler.
4042 hash
= hugetlb_fault_mutex_hash(h
, mapping
, idx
);
4043 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4044 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
4045 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4049 page
= alloc_huge_page(vma
, haddr
, 0);
4052 * Returning error will result in faulting task being
4053 * sent SIGBUS. The hugetlb fault mutex prevents two
4054 * tasks from racing to fault in the same page which
4055 * could result in false unable to allocate errors.
4056 * Page migration does not take the fault mutex, but
4057 * does a clear then write of pte's under page table
4058 * lock. Page fault code could race with migration,
4059 * notice the clear pte and try to allocate a page
4060 * here. Before returning error, get ptl and make
4061 * sure there really is no pte entry.
4063 ptl
= huge_pte_lock(h
, mm
, ptep
);
4064 if (!huge_pte_none(huge_ptep_get(ptep
))) {
4070 ret
= vmf_error(PTR_ERR(page
));
4073 clear_huge_page(page
, address
, pages_per_huge_page(h
));
4074 __SetPageUptodate(page
);
4077 if (vma
->vm_flags
& VM_MAYSHARE
) {
4078 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
4087 if (unlikely(anon_vma_prepare(vma
))) {
4089 goto backout_unlocked
;
4095 * If memory error occurs between mmap() and fault, some process
4096 * don't have hwpoisoned swap entry for errored virtual address.
4097 * So we need to block hugepage fault by PG_hwpoison bit check.
4099 if (unlikely(PageHWPoison(page
))) {
4100 ret
= VM_FAULT_HWPOISON_LARGE
|
4101 VM_FAULT_SET_HINDEX(hstate_index(h
));
4102 goto backout_unlocked
;
4107 * If we are going to COW a private mapping later, we examine the
4108 * pending reservations for this page now. This will ensure that
4109 * any allocations necessary to record that reservation occur outside
4112 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4113 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4115 goto backout_unlocked
;
4117 /* Just decrements count, does not deallocate */
4118 vma_end_reservation(h
, vma
, haddr
);
4121 ptl
= huge_pte_lock(h
, mm
, ptep
);
4122 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4127 if (!huge_pte_none(huge_ptep_get(ptep
)))
4131 ClearPagePrivate(page
);
4132 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
4134 page_dup_rmap(page
, true);
4135 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
4136 && (vma
->vm_flags
& VM_SHARED
)));
4137 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
4139 hugetlb_count_add(pages_per_huge_page(h
), mm
);
4140 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4141 /* Optimization, do the COW without a second fault */
4142 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
4148 * Only make newly allocated pages active. Existing pages found
4149 * in the pagecache could be !page_huge_active() if they have been
4150 * isolated for migration.
4153 set_page_huge_active(page
);
4163 restore_reserve_on_error(h
, vma
, haddr
, page
);
4169 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct address_space
*mapping
,
4172 unsigned long key
[2];
4175 key
[0] = (unsigned long) mapping
;
4178 hash
= jhash2((u32
*)&key
, sizeof(key
)/(sizeof(u32
)), 0);
4180 return hash
& (num_fault_mutexes
- 1);
4184 * For uniprocesor systems we always use a single mutex, so just
4185 * return 0 and avoid the hashing overhead.
4187 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct address_space
*mapping
,
4194 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4195 unsigned long address
, unsigned int flags
)
4202 struct page
*page
= NULL
;
4203 struct page
*pagecache_page
= NULL
;
4204 struct hstate
*h
= hstate_vma(vma
);
4205 struct address_space
*mapping
;
4206 int need_wait_lock
= 0;
4207 unsigned long haddr
= address
& huge_page_mask(h
);
4209 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4211 entry
= huge_ptep_get(ptep
);
4212 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4213 migration_entry_wait_huge(vma
, mm
, ptep
);
4215 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4216 return VM_FAULT_HWPOISON_LARGE
|
4217 VM_FAULT_SET_HINDEX(hstate_index(h
));
4219 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4221 return VM_FAULT_OOM
;
4224 mapping
= vma
->vm_file
->f_mapping
;
4225 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4228 * Serialize hugepage allocation and instantiation, so that we don't
4229 * get spurious allocation failures if two CPUs race to instantiate
4230 * the same page in the page cache.
4232 hash
= hugetlb_fault_mutex_hash(h
, mapping
, idx
);
4233 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4235 entry
= huge_ptep_get(ptep
);
4236 if (huge_pte_none(entry
)) {
4237 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4244 * entry could be a migration/hwpoison entry at this point, so this
4245 * check prevents the kernel from going below assuming that we have
4246 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4247 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4250 if (!pte_present(entry
))
4254 * If we are going to COW the mapping later, we examine the pending
4255 * reservations for this page now. This will ensure that any
4256 * allocations necessary to record that reservation occur outside the
4257 * spinlock. For private mappings, we also lookup the pagecache
4258 * page now as it is used to determine if a reservation has been
4261 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4262 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4266 /* Just decrements count, does not deallocate */
4267 vma_end_reservation(h
, vma
, haddr
);
4269 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4270 pagecache_page
= hugetlbfs_pagecache_page(h
,
4274 ptl
= huge_pte_lock(h
, mm
, ptep
);
4276 /* Check for a racing update before calling hugetlb_cow */
4277 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4281 * hugetlb_cow() requires page locks of pte_page(entry) and
4282 * pagecache_page, so here we need take the former one
4283 * when page != pagecache_page or !pagecache_page.
4285 page
= pte_page(entry
);
4286 if (page
!= pagecache_page
)
4287 if (!trylock_page(page
)) {
4294 if (flags
& FAULT_FLAG_WRITE
) {
4295 if (!huge_pte_write(entry
)) {
4296 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4297 pagecache_page
, ptl
);
4300 entry
= huge_pte_mkdirty(entry
);
4302 entry
= pte_mkyoung(entry
);
4303 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4304 flags
& FAULT_FLAG_WRITE
))
4305 update_mmu_cache(vma
, haddr
, ptep
);
4307 if (page
!= pagecache_page
)
4313 if (pagecache_page
) {
4314 unlock_page(pagecache_page
);
4315 put_page(pagecache_page
);
4318 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4320 * Generally it's safe to hold refcount during waiting page lock. But
4321 * here we just wait to defer the next page fault to avoid busy loop and
4322 * the page is not used after unlocked before returning from the current
4323 * page fault. So we are safe from accessing freed page, even if we wait
4324 * here without taking refcount.
4327 wait_on_page_locked(page
);
4332 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4333 * modifications for huge pages.
4335 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4337 struct vm_area_struct
*dst_vma
,
4338 unsigned long dst_addr
,
4339 unsigned long src_addr
,
4340 struct page
**pagep
)
4342 struct address_space
*mapping
;
4345 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4346 struct hstate
*h
= hstate_vma(dst_vma
);
4353 /* If a page already exists, then it's UFFDIO_COPY for
4354 * a non-missing case. Return -EEXIST.
4357 hugetlbfs_pagecache_present(h
, dst_vma
, dst_addr
)) {
4362 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4368 ret
= copy_huge_page_from_user(page
,
4369 (const void __user
*) src_addr
,
4370 pages_per_huge_page(h
), false);
4372 /* fallback to copy_from_user outside mmap_sem */
4373 if (unlikely(ret
)) {
4376 /* don't free the page */
4385 * The memory barrier inside __SetPageUptodate makes sure that
4386 * preceding stores to the page contents become visible before
4387 * the set_pte_at() write.
4389 __SetPageUptodate(page
);
4391 mapping
= dst_vma
->vm_file
->f_mapping
;
4392 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4395 * If shared, add to page cache
4398 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4401 goto out_release_nounlock
;
4404 * Serialization between remove_inode_hugepages() and
4405 * huge_add_to_page_cache() below happens through the
4406 * hugetlb_fault_mutex_table that here must be hold by
4409 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4411 goto out_release_nounlock
;
4414 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4418 * Recheck the i_size after holding PT lock to make sure not
4419 * to leave any page mapped (as page_mapped()) beyond the end
4420 * of the i_size (remove_inode_hugepages() is strict about
4421 * enforcing that). If we bail out here, we'll also leave a
4422 * page in the radix tree in the vm_shared case beyond the end
4423 * of the i_size, but remove_inode_hugepages() will take care
4424 * of it as soon as we drop the hugetlb_fault_mutex_table.
4426 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4429 goto out_release_unlock
;
4432 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4433 goto out_release_unlock
;
4436 page_dup_rmap(page
, true);
4438 ClearPagePrivate(page
);
4439 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4442 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4443 if (dst_vma
->vm_flags
& VM_WRITE
)
4444 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4445 _dst_pte
= pte_mkyoung(_dst_pte
);
4447 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4449 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4450 dst_vma
->vm_flags
& VM_WRITE
);
4451 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4453 /* No need to invalidate - it was non-present before */
4454 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4457 set_page_huge_active(page
);
4467 out_release_nounlock
:
4472 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4473 struct page
**pages
, struct vm_area_struct
**vmas
,
4474 unsigned long *position
, unsigned long *nr_pages
,
4475 long i
, unsigned int flags
, int *nonblocking
)
4477 unsigned long pfn_offset
;
4478 unsigned long vaddr
= *position
;
4479 unsigned long remainder
= *nr_pages
;
4480 struct hstate
*h
= hstate_vma(vma
);
4483 while (vaddr
< vma
->vm_end
&& remainder
) {
4485 spinlock_t
*ptl
= NULL
;
4490 * If we have a pending SIGKILL, don't keep faulting pages and
4491 * potentially allocating memory.
4493 if (fatal_signal_pending(current
)) {
4499 * Some archs (sparc64, sh*) have multiple pte_ts to
4500 * each hugepage. We have to make sure we get the
4501 * first, for the page indexing below to work.
4503 * Note that page table lock is not held when pte is null.
4505 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4508 ptl
= huge_pte_lock(h
, mm
, pte
);
4509 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4512 * When coredumping, it suits get_dump_page if we just return
4513 * an error where there's an empty slot with no huge pagecache
4514 * to back it. This way, we avoid allocating a hugepage, and
4515 * the sparse dumpfile avoids allocating disk blocks, but its
4516 * huge holes still show up with zeroes where they need to be.
4518 if (absent
&& (flags
& FOLL_DUMP
) &&
4519 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4527 * We need call hugetlb_fault for both hugepages under migration
4528 * (in which case hugetlb_fault waits for the migration,) and
4529 * hwpoisoned hugepages (in which case we need to prevent the
4530 * caller from accessing to them.) In order to do this, we use
4531 * here is_swap_pte instead of is_hugetlb_entry_migration and
4532 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4533 * both cases, and because we can't follow correct pages
4534 * directly from any kind of swap entries.
4536 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4537 ((flags
& FOLL_WRITE
) &&
4538 !huge_pte_write(huge_ptep_get(pte
)))) {
4540 unsigned int fault_flags
= 0;
4544 if (flags
& FOLL_WRITE
)
4545 fault_flags
|= FAULT_FLAG_WRITE
;
4547 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
4548 if (flags
& FOLL_NOWAIT
)
4549 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4550 FAULT_FLAG_RETRY_NOWAIT
;
4551 if (flags
& FOLL_TRIED
) {
4552 VM_WARN_ON_ONCE(fault_flags
&
4553 FAULT_FLAG_ALLOW_RETRY
);
4554 fault_flags
|= FAULT_FLAG_TRIED
;
4556 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4557 if (ret
& VM_FAULT_ERROR
) {
4558 err
= vm_fault_to_errno(ret
, flags
);
4562 if (ret
& VM_FAULT_RETRY
) {
4564 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4568 * VM_FAULT_RETRY must not return an
4569 * error, it will return zero
4572 * No need to update "position" as the
4573 * caller will not check it after
4574 * *nr_pages is set to 0.
4581 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4582 page
= pte_page(huge_ptep_get(pte
));
4585 * Instead of doing 'try_get_page()' below in the same_page
4586 * loop, just check the count once here.
4588 if (unlikely(page_count(page
) <= 0)) {
4598 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4609 if (vaddr
< vma
->vm_end
&& remainder
&&
4610 pfn_offset
< pages_per_huge_page(h
)) {
4612 * We use pfn_offset to avoid touching the pageframes
4613 * of this compound page.
4619 *nr_pages
= remainder
;
4621 * setting position is actually required only if remainder is
4622 * not zero but it's faster not to add a "if (remainder)"
4630 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4632 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4635 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4638 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4639 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4641 struct mm_struct
*mm
= vma
->vm_mm
;
4642 unsigned long start
= address
;
4645 struct hstate
*h
= hstate_vma(vma
);
4646 unsigned long pages
= 0;
4647 bool shared_pmd
= false;
4648 struct mmu_notifier_range range
;
4651 * In the case of shared PMDs, the area to flush could be beyond
4652 * start/end. Set range.start/range.end to cover the maximum possible
4653 * range if PMD sharing is possible.
4655 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
4656 0, vma
, mm
, start
, end
);
4657 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
4659 BUG_ON(address
>= end
);
4660 flush_cache_range(vma
, range
.start
, range
.end
);
4662 mmu_notifier_invalidate_range_start(&range
);
4663 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4664 for (; address
< end
; address
+= huge_page_size(h
)) {
4666 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4669 ptl
= huge_pte_lock(h
, mm
, ptep
);
4670 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4676 pte
= huge_ptep_get(ptep
);
4677 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4681 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4682 swp_entry_t entry
= pte_to_swp_entry(pte
);
4684 if (is_write_migration_entry(entry
)) {
4687 make_migration_entry_read(&entry
);
4688 newpte
= swp_entry_to_pte(entry
);
4689 set_huge_swap_pte_at(mm
, address
, ptep
,
4690 newpte
, huge_page_size(h
));
4696 if (!huge_pte_none(pte
)) {
4699 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
4700 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
4701 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4702 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
4708 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4709 * may have cleared our pud entry and done put_page on the page table:
4710 * once we release i_mmap_rwsem, another task can do the final put_page
4711 * and that page table be reused and filled with junk. If we actually
4712 * did unshare a page of pmds, flush the range corresponding to the pud.
4715 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
4717 flush_hugetlb_tlb_range(vma
, start
, end
);
4719 * No need to call mmu_notifier_invalidate_range() we are downgrading
4720 * page table protection not changing it to point to a new page.
4722 * See Documentation/vm/mmu_notifier.rst
4724 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4725 mmu_notifier_invalidate_range_end(&range
);
4727 return pages
<< h
->order
;
4730 int hugetlb_reserve_pages(struct inode
*inode
,
4732 struct vm_area_struct
*vma
,
4733 vm_flags_t vm_flags
)
4736 struct hstate
*h
= hstate_inode(inode
);
4737 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4738 struct resv_map
*resv_map
;
4741 /* This should never happen */
4743 VM_WARN(1, "%s called with a negative range\n", __func__
);
4748 * Only apply hugepage reservation if asked. At fault time, an
4749 * attempt will be made for VM_NORESERVE to allocate a page
4750 * without using reserves
4752 if (vm_flags
& VM_NORESERVE
)
4756 * Shared mappings base their reservation on the number of pages that
4757 * are already allocated on behalf of the file. Private mappings need
4758 * to reserve the full area even if read-only as mprotect() may be
4759 * called to make the mapping read-write. Assume !vma is a shm mapping
4761 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4763 * resv_map can not be NULL as hugetlb_reserve_pages is only
4764 * called for inodes for which resv_maps were created (see
4765 * hugetlbfs_get_inode).
4767 resv_map
= inode_resv_map(inode
);
4769 chg
= region_chg(resv_map
, from
, to
);
4772 resv_map
= resv_map_alloc();
4778 set_vma_resv_map(vma
, resv_map
);
4779 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4788 * There must be enough pages in the subpool for the mapping. If
4789 * the subpool has a minimum size, there may be some global
4790 * reservations already in place (gbl_reserve).
4792 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4793 if (gbl_reserve
< 0) {
4799 * Check enough hugepages are available for the reservation.
4800 * Hand the pages back to the subpool if there are not
4802 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4804 /* put back original number of pages, chg */
4805 (void)hugepage_subpool_put_pages(spool
, chg
);
4810 * Account for the reservations made. Shared mappings record regions
4811 * that have reservations as they are shared by multiple VMAs.
4812 * When the last VMA disappears, the region map says how much
4813 * the reservation was and the page cache tells how much of
4814 * the reservation was consumed. Private mappings are per-VMA and
4815 * only the consumed reservations are tracked. When the VMA
4816 * disappears, the original reservation is the VMA size and the
4817 * consumed reservations are stored in the map. Hence, nothing
4818 * else has to be done for private mappings here
4820 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4821 long add
= region_add(resv_map
, from
, to
);
4823 if (unlikely(chg
> add
)) {
4825 * pages in this range were added to the reserve
4826 * map between region_chg and region_add. This
4827 * indicates a race with alloc_huge_page. Adjust
4828 * the subpool and reserve counts modified above
4829 * based on the difference.
4833 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4835 hugetlb_acct_memory(h
, -rsv_adjust
);
4840 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4841 /* Don't call region_abort if region_chg failed */
4843 region_abort(resv_map
, from
, to
);
4844 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4845 kref_put(&resv_map
->refs
, resv_map_release
);
4849 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4852 struct hstate
*h
= hstate_inode(inode
);
4853 struct resv_map
*resv_map
= inode_resv_map(inode
);
4855 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4859 * Since this routine can be called in the evict inode path for all
4860 * hugetlbfs inodes, resv_map could be NULL.
4863 chg
= region_del(resv_map
, start
, end
);
4865 * region_del() can fail in the rare case where a region
4866 * must be split and another region descriptor can not be
4867 * allocated. If end == LONG_MAX, it will not fail.
4873 spin_lock(&inode
->i_lock
);
4874 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4875 spin_unlock(&inode
->i_lock
);
4878 * If the subpool has a minimum size, the number of global
4879 * reservations to be released may be adjusted.
4881 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4882 hugetlb_acct_memory(h
, -gbl_reserve
);
4887 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4888 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4889 struct vm_area_struct
*vma
,
4890 unsigned long addr
, pgoff_t idx
)
4892 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4894 unsigned long sbase
= saddr
& PUD_MASK
;
4895 unsigned long s_end
= sbase
+ PUD_SIZE
;
4897 /* Allow segments to share if only one is marked locked */
4898 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4899 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4902 * match the virtual addresses, permission and the alignment of the
4905 if (pmd_index(addr
) != pmd_index(saddr
) ||
4906 vm_flags
!= svm_flags
||
4907 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4913 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4915 unsigned long base
= addr
& PUD_MASK
;
4916 unsigned long end
= base
+ PUD_SIZE
;
4919 * check on proper vm_flags and page table alignment
4921 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
4927 * Determine if start,end range within vma could be mapped by shared pmd.
4928 * If yes, adjust start and end to cover range associated with possible
4929 * shared pmd mappings.
4931 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
4932 unsigned long *start
, unsigned long *end
)
4934 unsigned long v_start
= ALIGN(vma
->vm_start
, PUD_SIZE
),
4935 v_end
= ALIGN_DOWN(vma
->vm_end
, PUD_SIZE
);
4938 * vma need span at least one aligned PUD size and the start,end range
4939 * must at least partialy within it.
4941 if (!(vma
->vm_flags
& VM_MAYSHARE
) || !(v_end
> v_start
) ||
4942 (*end
<= v_start
) || (*start
>= v_end
))
4945 /* Extend the range to be PUD aligned for a worst case scenario */
4946 if (*start
> v_start
)
4947 *start
= ALIGN_DOWN(*start
, PUD_SIZE
);
4950 *end
= ALIGN(*end
, PUD_SIZE
);
4954 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4955 * and returns the corresponding pte. While this is not necessary for the
4956 * !shared pmd case because we can allocate the pmd later as well, it makes the
4957 * code much cleaner. pmd allocation is essential for the shared case because
4958 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4959 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4960 * bad pmd for sharing.
4962 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4964 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4965 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4966 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4968 struct vm_area_struct
*svma
;
4969 unsigned long saddr
;
4974 if (!vma_shareable(vma
, addr
))
4975 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4977 i_mmap_lock_read(mapping
);
4978 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4982 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4984 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
4985 vma_mmu_pagesize(svma
));
4987 get_page(virt_to_page(spte
));
4996 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
4997 if (pud_none(*pud
)) {
4998 pud_populate(mm
, pud
,
4999 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
5002 put_page(virt_to_page(spte
));
5006 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5007 i_mmap_unlock_read(mapping
);
5012 * unmap huge page backed by shared pte.
5014 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5015 * indicated by page_count > 1, unmap is achieved by clearing pud and
5016 * decrementing the ref count. If count == 1, the pte page is not shared.
5018 * called with page table lock held.
5020 * returns: 1 successfully unmapped a shared pte page
5021 * 0 the underlying pte page is not shared, or it is the last user
5023 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5025 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
5026 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
5027 pud_t
*pud
= pud_offset(p4d
, *addr
);
5029 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
5030 if (page_count(virt_to_page(ptep
)) == 1)
5034 put_page(virt_to_page(ptep
));
5036 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
5039 #define want_pmd_share() (1)
5040 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5041 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
5046 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
5051 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
5052 unsigned long *start
, unsigned long *end
)
5055 #define want_pmd_share() (0)
5056 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5058 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5059 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
5060 unsigned long addr
, unsigned long sz
)
5067 pgd
= pgd_offset(mm
, addr
);
5068 p4d
= p4d_alloc(mm
, pgd
, addr
);
5071 pud
= pud_alloc(mm
, p4d
, addr
);
5073 if (sz
== PUD_SIZE
) {
5076 BUG_ON(sz
!= PMD_SIZE
);
5077 if (want_pmd_share() && pud_none(*pud
))
5078 pte
= huge_pmd_share(mm
, addr
, pud
);
5080 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
5083 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
5089 * huge_pte_offset() - Walk the page table to resolve the hugepage
5090 * entry at address @addr
5092 * Return: Pointer to page table or swap entry (PUD or PMD) for
5093 * address @addr, or NULL if a p*d_none() entry is encountered and the
5094 * size @sz doesn't match the hugepage size at this level of the page
5097 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
5098 unsigned long addr
, unsigned long sz
)
5102 pud_t
*pud
, pud_entry
;
5103 pmd_t
*pmd
, pmd_entry
;
5105 pgd
= pgd_offset(mm
, addr
);
5106 if (!pgd_present(*pgd
))
5108 p4d
= p4d_offset(pgd
, addr
);
5109 if (!p4d_present(*p4d
))
5112 pud
= pud_offset(p4d
, addr
);
5113 pud_entry
= READ_ONCE(*pud
);
5114 if (sz
!= PUD_SIZE
&& pud_none(pud_entry
))
5116 /* hugepage or swap? */
5117 if (pud_huge(pud_entry
) || !pud_present(pud_entry
))
5118 return (pte_t
*)pud
;
5120 pmd
= pmd_offset(pud
, addr
);
5121 pmd_entry
= READ_ONCE(*pmd
);
5122 if (sz
!= PMD_SIZE
&& pmd_none(pmd_entry
))
5124 /* hugepage or swap? */
5125 if (pmd_huge(pmd_entry
) || !pmd_present(pmd_entry
))
5126 return (pte_t
*)pmd
;
5131 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5134 * These functions are overwritable if your architecture needs its own
5137 struct page
* __weak
5138 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
5141 return ERR_PTR(-EINVAL
);
5144 struct page
* __weak
5145 follow_huge_pd(struct vm_area_struct
*vma
,
5146 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
5148 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5152 struct page
* __weak
5153 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
5154 pmd_t
*pmd
, int flags
)
5156 struct page
*page
= NULL
;
5160 ptl
= pmd_lockptr(mm
, pmd
);
5163 * make sure that the address range covered by this pmd is not
5164 * unmapped from other threads.
5166 if (!pmd_huge(*pmd
))
5168 pte
= huge_ptep_get((pte_t
*)pmd
);
5169 if (pte_present(pte
)) {
5170 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
5171 if (flags
& FOLL_GET
)
5174 if (is_hugetlb_entry_migration(pte
)) {
5176 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5180 * hwpoisoned entry is treated as no_page_table in
5181 * follow_page_mask().
5189 struct page
* __weak
5190 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5191 pud_t
*pud
, int flags
)
5193 if (flags
& FOLL_GET
)
5196 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5199 struct page
* __weak
5200 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5202 if (flags
& FOLL_GET
)
5205 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5208 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5212 spin_lock(&hugetlb_lock
);
5213 if (!PageHeadHuge(page
) || !page_huge_active(page
) ||
5214 !get_page_unless_zero(page
)) {
5218 clear_page_huge_active(page
);
5219 list_move_tail(&page
->lru
, list
);
5221 spin_unlock(&hugetlb_lock
);
5225 void putback_active_hugepage(struct page
*page
)
5227 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5228 spin_lock(&hugetlb_lock
);
5229 set_page_huge_active(page
);
5230 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5231 spin_unlock(&hugetlb_lock
);
5235 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5237 struct hstate
*h
= page_hstate(oldpage
);
5239 hugetlb_cgroup_migrate(oldpage
, newpage
);
5240 set_page_owner_migrate_reason(newpage
, reason
);
5243 * transfer temporary state of the new huge page. This is
5244 * reverse to other transitions because the newpage is going to
5245 * be final while the old one will be freed so it takes over
5246 * the temporary status.
5248 * Also note that we have to transfer the per-node surplus state
5249 * here as well otherwise the global surplus count will not match
5252 if (PageHugeTemporary(newpage
)) {
5253 int old_nid
= page_to_nid(oldpage
);
5254 int new_nid
= page_to_nid(newpage
);
5256 SetPageHugeTemporary(oldpage
);
5257 ClearPageHugeTemporary(newpage
);
5259 spin_lock(&hugetlb_lock
);
5260 if (h
->surplus_huge_pages_node
[old_nid
]) {
5261 h
->surplus_huge_pages_node
[old_nid
]--;
5262 h
->surplus_huge_pages_node
[new_nid
]++;
5264 spin_unlock(&hugetlb_lock
);