2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
8 #include <linux/seq_file.h>
9 #include <linux/sysctl.h>
10 #include <linux/highmem.h>
11 #include <linux/mmu_notifier.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/compiler.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/sched/signal.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
36 #include <linux/userfaultfd_k.h>
39 int hugepages_treat_as_movable
;
41 int hugetlb_max_hstate __read_mostly
;
42 unsigned int default_hstate_idx
;
43 struct hstate hstates
[HUGE_MAX_HSTATE
];
45 * Minimum page order among possible hugepage sizes, set to a proper value
48 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
50 __initdata
LIST_HEAD(huge_boot_pages
);
52 /* for command line parsing */
53 static struct hstate
* __initdata parsed_hstate
;
54 static unsigned long __initdata default_hstate_max_huge_pages
;
55 static unsigned long __initdata default_hstate_size
;
56 static bool __initdata parsed_valid_hugepagesz
= true;
59 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
60 * free_huge_pages, and surplus_huge_pages.
62 DEFINE_SPINLOCK(hugetlb_lock
);
65 * Serializes faults on the same logical page. This is used to
66 * prevent spurious OOMs when the hugepage pool is fully utilized.
68 static int num_fault_mutexes
;
69 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
71 /* Forward declaration */
72 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
74 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
76 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
78 spin_unlock(&spool
->lock
);
80 /* If no pages are used, and no other handles to the subpool
81 * remain, give up any reservations mased on minimum size and
84 if (spool
->min_hpages
!= -1)
85 hugetlb_acct_memory(spool
->hstate
,
91 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
94 struct hugepage_subpool
*spool
;
96 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
100 spin_lock_init(&spool
->lock
);
102 spool
->max_hpages
= max_hpages
;
104 spool
->min_hpages
= min_hpages
;
106 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
110 spool
->rsv_hpages
= min_hpages
;
115 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
117 spin_lock(&spool
->lock
);
118 BUG_ON(!spool
->count
);
120 unlock_or_release_subpool(spool
);
124 * Subpool accounting for allocating and reserving pages.
125 * Return -ENOMEM if there are not enough resources to satisfy the
126 * the request. Otherwise, return the number of pages by which the
127 * global pools must be adjusted (upward). The returned value may
128 * only be different than the passed value (delta) in the case where
129 * a subpool minimum size must be manitained.
131 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
139 spin_lock(&spool
->lock
);
141 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
142 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
143 spool
->used_hpages
+= delta
;
150 /* minimum size accounting */
151 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
152 if (delta
> spool
->rsv_hpages
) {
154 * Asking for more reserves than those already taken on
155 * behalf of subpool. Return difference.
157 ret
= delta
- spool
->rsv_hpages
;
158 spool
->rsv_hpages
= 0;
160 ret
= 0; /* reserves already accounted for */
161 spool
->rsv_hpages
-= delta
;
166 spin_unlock(&spool
->lock
);
171 * Subpool accounting for freeing and unreserving pages.
172 * Return the number of global page reservations that must be dropped.
173 * The return value may only be different than the passed value (delta)
174 * in the case where a subpool minimum size must be maintained.
176 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
184 spin_lock(&spool
->lock
);
186 if (spool
->max_hpages
!= -1) /* maximum size accounting */
187 spool
->used_hpages
-= delta
;
189 /* minimum size accounting */
190 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
191 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
194 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
196 spool
->rsv_hpages
+= delta
;
197 if (spool
->rsv_hpages
> spool
->min_hpages
)
198 spool
->rsv_hpages
= spool
->min_hpages
;
202 * If hugetlbfs_put_super couldn't free spool due to an outstanding
203 * quota reference, free it now.
205 unlock_or_release_subpool(spool
);
210 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
212 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
215 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
217 return subpool_inode(file_inode(vma
->vm_file
));
221 * Region tracking -- allows tracking of reservations and instantiated pages
222 * across the pages in a mapping.
224 * The region data structures are embedded into a resv_map and protected
225 * by a resv_map's lock. The set of regions within the resv_map represent
226 * reservations for huge pages, or huge pages that have already been
227 * instantiated within the map. The from and to elements are huge page
228 * indicies into the associated mapping. from indicates the starting index
229 * of the region. to represents the first index past the end of the region.
231 * For example, a file region structure with from == 0 and to == 4 represents
232 * four huge pages in a mapping. It is important to note that the to element
233 * represents the first element past the end of the region. This is used in
234 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
236 * Interval notation of the form [from, to) will be used to indicate that
237 * the endpoint from is inclusive and to is exclusive.
240 struct list_head link
;
246 * Add the huge page range represented by [f, t) to the reserve
247 * map. In the normal case, existing regions will be expanded
248 * to accommodate the specified range. Sufficient regions should
249 * exist for expansion due to the previous call to region_chg
250 * with the same range. However, it is possible that region_del
251 * could have been called after region_chg and modifed the map
252 * in such a way that no region exists to be expanded. In this
253 * case, pull a region descriptor from the cache associated with
254 * the map and use that for the new range.
256 * Return the number of new huge pages added to the map. This
257 * number is greater than or equal to zero.
259 static long region_add(struct resv_map
*resv
, long f
, long t
)
261 struct list_head
*head
= &resv
->regions
;
262 struct file_region
*rg
, *nrg
, *trg
;
265 spin_lock(&resv
->lock
);
266 /* Locate the region we are either in or before. */
267 list_for_each_entry(rg
, head
, link
)
272 * If no region exists which can be expanded to include the
273 * specified range, the list must have been modified by an
274 * interleving call to region_del(). Pull a region descriptor
275 * from the cache and use it for this range.
277 if (&rg
->link
== head
|| t
< rg
->from
) {
278 VM_BUG_ON(resv
->region_cache_count
<= 0);
280 resv
->region_cache_count
--;
281 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
283 list_del(&nrg
->link
);
287 list_add(&nrg
->link
, rg
->link
.prev
);
293 /* Round our left edge to the current segment if it encloses us. */
297 /* Check for and consume any regions we now overlap with. */
299 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
300 if (&rg
->link
== head
)
305 /* If this area reaches higher then extend our area to
306 * include it completely. If this is not the first area
307 * which we intend to reuse, free it. */
311 /* Decrement return value by the deleted range.
312 * Another range will span this area so that by
313 * end of routine add will be >= zero
315 add
-= (rg
->to
- rg
->from
);
321 add
+= (nrg
->from
- f
); /* Added to beginning of region */
323 add
+= t
- nrg
->to
; /* Added to end of region */
327 resv
->adds_in_progress
--;
328 spin_unlock(&resv
->lock
);
334 * Examine the existing reserve map and determine how many
335 * huge pages in the specified range [f, t) are NOT currently
336 * represented. This routine is called before a subsequent
337 * call to region_add that will actually modify the reserve
338 * map to add the specified range [f, t). region_chg does
339 * not change the number of huge pages represented by the
340 * map. However, if the existing regions in the map can not
341 * be expanded to represent the new range, a new file_region
342 * structure is added to the map as a placeholder. This is
343 * so that the subsequent region_add call will have all the
344 * regions it needs and will not fail.
346 * Upon entry, region_chg will also examine the cache of region descriptors
347 * associated with the map. If there are not enough descriptors cached, one
348 * will be allocated for the in progress add operation.
350 * Returns the number of huge pages that need to be added to the existing
351 * reservation map for the range [f, t). This number is greater or equal to
352 * zero. -ENOMEM is returned if a new file_region structure or cache entry
353 * is needed and can not be allocated.
355 static long region_chg(struct resv_map
*resv
, long f
, long t
)
357 struct list_head
*head
= &resv
->regions
;
358 struct file_region
*rg
, *nrg
= NULL
;
362 spin_lock(&resv
->lock
);
364 resv
->adds_in_progress
++;
367 * Check for sufficient descriptors in the cache to accommodate
368 * the number of in progress add operations.
370 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
371 struct file_region
*trg
;
373 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
374 /* Must drop lock to allocate a new descriptor. */
375 resv
->adds_in_progress
--;
376 spin_unlock(&resv
->lock
);
378 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
384 spin_lock(&resv
->lock
);
385 list_add(&trg
->link
, &resv
->region_cache
);
386 resv
->region_cache_count
++;
390 /* Locate the region we are before or in. */
391 list_for_each_entry(rg
, head
, link
)
395 /* If we are below the current region then a new region is required.
396 * Subtle, allocate a new region at the position but make it zero
397 * size such that we can guarantee to record the reservation. */
398 if (&rg
->link
== head
|| t
< rg
->from
) {
400 resv
->adds_in_progress
--;
401 spin_unlock(&resv
->lock
);
402 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
408 INIT_LIST_HEAD(&nrg
->link
);
412 list_add(&nrg
->link
, rg
->link
.prev
);
417 /* Round our left edge to the current segment if it encloses us. */
422 /* Check for and consume any regions we now overlap with. */
423 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
424 if (&rg
->link
== head
)
429 /* We overlap with this area, if it extends further than
430 * us then we must extend ourselves. Account for its
431 * existing reservation. */
436 chg
-= rg
->to
- rg
->from
;
440 spin_unlock(&resv
->lock
);
441 /* We already know we raced and no longer need the new region */
445 spin_unlock(&resv
->lock
);
450 * Abort the in progress add operation. The adds_in_progress field
451 * of the resv_map keeps track of the operations in progress between
452 * calls to region_chg and region_add. Operations are sometimes
453 * aborted after the call to region_chg. In such cases, region_abort
454 * is called to decrement the adds_in_progress counter.
456 * NOTE: The range arguments [f, t) are not needed or used in this
457 * routine. They are kept to make reading the calling code easier as
458 * arguments will match the associated region_chg call.
460 static void region_abort(struct resv_map
*resv
, long f
, long t
)
462 spin_lock(&resv
->lock
);
463 VM_BUG_ON(!resv
->region_cache_count
);
464 resv
->adds_in_progress
--;
465 spin_unlock(&resv
->lock
);
469 * Delete the specified range [f, t) from the reserve map. If the
470 * t parameter is LONG_MAX, this indicates that ALL regions after f
471 * should be deleted. Locate the regions which intersect [f, t)
472 * and either trim, delete or split the existing regions.
474 * Returns the number of huge pages deleted from the reserve map.
475 * In the normal case, the return value is zero or more. In the
476 * case where a region must be split, a new region descriptor must
477 * be allocated. If the allocation fails, -ENOMEM will be returned.
478 * NOTE: If the parameter t == LONG_MAX, then we will never split
479 * a region and possibly return -ENOMEM. Callers specifying
480 * t == LONG_MAX do not need to check for -ENOMEM error.
482 static long region_del(struct resv_map
*resv
, long f
, long t
)
484 struct list_head
*head
= &resv
->regions
;
485 struct file_region
*rg
, *trg
;
486 struct file_region
*nrg
= NULL
;
490 spin_lock(&resv
->lock
);
491 list_for_each_entry_safe(rg
, trg
, head
, link
) {
493 * Skip regions before the range to be deleted. file_region
494 * ranges are normally of the form [from, to). However, there
495 * may be a "placeholder" entry in the map which is of the form
496 * (from, to) with from == to. Check for placeholder entries
497 * at the beginning of the range to be deleted.
499 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
505 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
507 * Check for an entry in the cache before dropping
508 * lock and attempting allocation.
511 resv
->region_cache_count
> resv
->adds_in_progress
) {
512 nrg
= list_first_entry(&resv
->region_cache
,
515 list_del(&nrg
->link
);
516 resv
->region_cache_count
--;
520 spin_unlock(&resv
->lock
);
521 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
529 /* New entry for end of split region */
532 INIT_LIST_HEAD(&nrg
->link
);
534 /* Original entry is trimmed */
537 list_add(&nrg
->link
, &rg
->link
);
542 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
543 del
+= rg
->to
- rg
->from
;
549 if (f
<= rg
->from
) { /* Trim beginning of region */
552 } else { /* Trim end of region */
558 spin_unlock(&resv
->lock
);
564 * A rare out of memory error was encountered which prevented removal of
565 * the reserve map region for a page. The huge page itself was free'ed
566 * and removed from the page cache. This routine will adjust the subpool
567 * usage count, and the global reserve count if needed. By incrementing
568 * these counts, the reserve map entry which could not be deleted will
569 * appear as a "reserved" entry instead of simply dangling with incorrect
572 void hugetlb_fix_reserve_counts(struct inode
*inode
)
574 struct hugepage_subpool
*spool
= subpool_inode(inode
);
577 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
579 struct hstate
*h
= hstate_inode(inode
);
581 hugetlb_acct_memory(h
, 1);
586 * Count and return the number of huge pages in the reserve map
587 * that intersect with the range [f, t).
589 static long region_count(struct resv_map
*resv
, long f
, long t
)
591 struct list_head
*head
= &resv
->regions
;
592 struct file_region
*rg
;
595 spin_lock(&resv
->lock
);
596 /* Locate each segment we overlap with, and count that overlap. */
597 list_for_each_entry(rg
, head
, link
) {
606 seg_from
= max(rg
->from
, f
);
607 seg_to
= min(rg
->to
, t
);
609 chg
+= seg_to
- seg_from
;
611 spin_unlock(&resv
->lock
);
617 * Convert the address within this vma to the page offset within
618 * the mapping, in pagecache page units; huge pages here.
620 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
621 struct vm_area_struct
*vma
, unsigned long address
)
623 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
624 (vma
->vm_pgoff
>> huge_page_order(h
));
627 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
628 unsigned long address
)
630 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
632 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
635 * Return the size of the pages allocated when backing a VMA. In the majority
636 * cases this will be same size as used by the page table entries.
638 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
640 struct hstate
*hstate
;
642 if (!is_vm_hugetlb_page(vma
))
645 hstate
= hstate_vma(vma
);
647 return 1UL << huge_page_shift(hstate
);
649 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
652 * Return the page size being used by the MMU to back a VMA. In the majority
653 * of cases, the page size used by the kernel matches the MMU size. On
654 * architectures where it differs, an architecture-specific version of this
655 * function is required.
657 #ifndef vma_mmu_pagesize
658 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
660 return vma_kernel_pagesize(vma
);
665 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
666 * bits of the reservation map pointer, which are always clear due to
669 #define HPAGE_RESV_OWNER (1UL << 0)
670 #define HPAGE_RESV_UNMAPPED (1UL << 1)
671 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
674 * These helpers are used to track how many pages are reserved for
675 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
676 * is guaranteed to have their future faults succeed.
678 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
679 * the reserve counters are updated with the hugetlb_lock held. It is safe
680 * to reset the VMA at fork() time as it is not in use yet and there is no
681 * chance of the global counters getting corrupted as a result of the values.
683 * The private mapping reservation is represented in a subtly different
684 * manner to a shared mapping. A shared mapping has a region map associated
685 * with the underlying file, this region map represents the backing file
686 * pages which have ever had a reservation assigned which this persists even
687 * after the page is instantiated. A private mapping has a region map
688 * associated with the original mmap which is attached to all VMAs which
689 * reference it, this region map represents those offsets which have consumed
690 * reservation ie. where pages have been instantiated.
692 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
694 return (unsigned long)vma
->vm_private_data
;
697 static void set_vma_private_data(struct vm_area_struct
*vma
,
700 vma
->vm_private_data
= (void *)value
;
703 struct resv_map
*resv_map_alloc(void)
705 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
706 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
708 if (!resv_map
|| !rg
) {
714 kref_init(&resv_map
->refs
);
715 spin_lock_init(&resv_map
->lock
);
716 INIT_LIST_HEAD(&resv_map
->regions
);
718 resv_map
->adds_in_progress
= 0;
720 INIT_LIST_HEAD(&resv_map
->region_cache
);
721 list_add(&rg
->link
, &resv_map
->region_cache
);
722 resv_map
->region_cache_count
= 1;
727 void resv_map_release(struct kref
*ref
)
729 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
730 struct list_head
*head
= &resv_map
->region_cache
;
731 struct file_region
*rg
, *trg
;
733 /* Clear out any active regions before we release the map. */
734 region_del(resv_map
, 0, LONG_MAX
);
736 /* ... and any entries left in the cache */
737 list_for_each_entry_safe(rg
, trg
, head
, link
) {
742 VM_BUG_ON(resv_map
->adds_in_progress
);
747 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
749 return inode
->i_mapping
->private_data
;
752 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
754 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
755 if (vma
->vm_flags
& VM_MAYSHARE
) {
756 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
757 struct inode
*inode
= mapping
->host
;
759 return inode_resv_map(inode
);
762 return (struct resv_map
*)(get_vma_private_data(vma
) &
767 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
769 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
770 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
772 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
773 HPAGE_RESV_MASK
) | (unsigned long)map
);
776 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
778 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
779 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
781 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
784 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
786 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
788 return (get_vma_private_data(vma
) & flag
) != 0;
791 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
792 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
794 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
795 if (!(vma
->vm_flags
& VM_MAYSHARE
))
796 vma
->vm_private_data
= (void *)0;
799 /* Returns true if the VMA has associated reserve pages */
800 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
802 if (vma
->vm_flags
& VM_NORESERVE
) {
804 * This address is already reserved by other process(chg == 0),
805 * so, we should decrement reserved count. Without decrementing,
806 * reserve count remains after releasing inode, because this
807 * allocated page will go into page cache and is regarded as
808 * coming from reserved pool in releasing step. Currently, we
809 * don't have any other solution to deal with this situation
810 * properly, so add work-around here.
812 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
818 /* Shared mappings always use reserves */
819 if (vma
->vm_flags
& VM_MAYSHARE
) {
821 * We know VM_NORESERVE is not set. Therefore, there SHOULD
822 * be a region map for all pages. The only situation where
823 * there is no region map is if a hole was punched via
824 * fallocate. In this case, there really are no reverves to
825 * use. This situation is indicated if chg != 0.
834 * Only the process that called mmap() has reserves for
837 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
839 * Like the shared case above, a hole punch or truncate
840 * could have been performed on the private mapping.
841 * Examine the value of chg to determine if reserves
842 * actually exist or were previously consumed.
843 * Very Subtle - The value of chg comes from a previous
844 * call to vma_needs_reserves(). The reserve map for
845 * private mappings has different (opposite) semantics
846 * than that of shared mappings. vma_needs_reserves()
847 * has already taken this difference in semantics into
848 * account. Therefore, the meaning of chg is the same
849 * as in the shared case above. Code could easily be
850 * combined, but keeping it separate draws attention to
851 * subtle differences.
862 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
864 int nid
= page_to_nid(page
);
865 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
866 h
->free_huge_pages
++;
867 h
->free_huge_pages_node
[nid
]++;
870 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
874 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
875 if (!is_migrate_isolate_page(page
))
878 * if 'non-isolated free hugepage' not found on the list,
879 * the allocation fails.
881 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
883 list_move(&page
->lru
, &h
->hugepage_activelist
);
884 set_page_refcounted(page
);
885 h
->free_huge_pages
--;
886 h
->free_huge_pages_node
[nid
]--;
890 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
895 if (nid
!= NUMA_NO_NODE
)
896 return dequeue_huge_page_node_exact(h
, nid
);
898 for_each_online_node(node
) {
899 page
= dequeue_huge_page_node_exact(h
, node
);
906 /* Movability of hugepages depends on migration support. */
907 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
909 if (hugepages_treat_as_movable
|| hugepage_migration_supported(h
))
910 return GFP_HIGHUSER_MOVABLE
;
915 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
916 struct vm_area_struct
*vma
,
917 unsigned long address
, int avoid_reserve
,
920 struct page
*page
= NULL
;
921 struct mempolicy
*mpol
;
922 nodemask_t
*nodemask
;
925 struct zonelist
*zonelist
;
928 unsigned int cpuset_mems_cookie
;
931 * A child process with MAP_PRIVATE mappings created by their parent
932 * have no page reserves. This check ensures that reservations are
933 * not "stolen". The child may still get SIGKILLed
935 if (!vma_has_reserves(vma
, chg
) &&
936 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
939 /* If reserves cannot be used, ensure enough pages are in the pool */
940 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
944 cpuset_mems_cookie
= read_mems_allowed_begin();
945 gfp_mask
= htlb_alloc_mask(h
);
946 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
947 zonelist
= node_zonelist(nid
, gfp_mask
);
949 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
950 MAX_NR_ZONES
- 1, nodemask
) {
951 if (cpuset_zone_allowed(zone
, gfp_mask
)) {
952 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
956 if (!vma_has_reserves(vma
, chg
))
959 SetPagePrivate(page
);
960 h
->resv_huge_pages
--;
967 if (unlikely(!page
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
976 * common helper functions for hstate_next_node_to_{alloc|free}.
977 * We may have allocated or freed a huge page based on a different
978 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
979 * be outside of *nodes_allowed. Ensure that we use an allowed
980 * node for alloc or free.
982 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
984 nid
= next_node_in(nid
, *nodes_allowed
);
985 VM_BUG_ON(nid
>= MAX_NUMNODES
);
990 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
992 if (!node_isset(nid
, *nodes_allowed
))
993 nid
= next_node_allowed(nid
, nodes_allowed
);
998 * returns the previously saved node ["this node"] from which to
999 * allocate a persistent huge page for the pool and advance the
1000 * next node from which to allocate, handling wrap at end of node
1003 static int hstate_next_node_to_alloc(struct hstate
*h
,
1004 nodemask_t
*nodes_allowed
)
1008 VM_BUG_ON(!nodes_allowed
);
1010 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1011 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1017 * helper for free_pool_huge_page() - return the previously saved
1018 * node ["this node"] from which to free a huge page. Advance the
1019 * next node id whether or not we find a free huge page to free so
1020 * that the next attempt to free addresses the next node.
1022 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1026 VM_BUG_ON(!nodes_allowed
);
1028 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1029 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1034 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1035 for (nr_nodes = nodes_weight(*mask); \
1037 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1040 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1041 for (nr_nodes = nodes_weight(*mask); \
1043 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1046 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1047 static void destroy_compound_gigantic_page(struct page
*page
,
1051 int nr_pages
= 1 << order
;
1052 struct page
*p
= page
+ 1;
1054 atomic_set(compound_mapcount_ptr(page
), 0);
1055 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1056 clear_compound_head(p
);
1057 set_page_refcounted(p
);
1060 set_compound_order(page
, 0);
1061 __ClearPageHead(page
);
1064 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1066 free_contig_range(page_to_pfn(page
), 1 << order
);
1069 static int __alloc_gigantic_page(unsigned long start_pfn
,
1070 unsigned long nr_pages
)
1072 unsigned long end_pfn
= start_pfn
+ nr_pages
;
1073 return alloc_contig_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
,
1077 static bool pfn_range_valid_gigantic(struct zone
*z
,
1078 unsigned long start_pfn
, unsigned long nr_pages
)
1080 unsigned long i
, end_pfn
= start_pfn
+ nr_pages
;
1083 for (i
= start_pfn
; i
< end_pfn
; i
++) {
1087 page
= pfn_to_page(i
);
1089 if (page_zone(page
) != z
)
1092 if (PageReserved(page
))
1095 if (page_count(page
) > 0)
1105 static bool zone_spans_last_pfn(const struct zone
*zone
,
1106 unsigned long start_pfn
, unsigned long nr_pages
)
1108 unsigned long last_pfn
= start_pfn
+ nr_pages
- 1;
1109 return zone_spans_pfn(zone
, last_pfn
);
1112 static struct page
*alloc_gigantic_page(int nid
, unsigned int order
)
1114 unsigned long nr_pages
= 1 << order
;
1115 unsigned long ret
, pfn
, flags
;
1118 z
= NODE_DATA(nid
)->node_zones
;
1119 for (; z
- NODE_DATA(nid
)->node_zones
< MAX_NR_ZONES
; z
++) {
1120 spin_lock_irqsave(&z
->lock
, flags
);
1122 pfn
= ALIGN(z
->zone_start_pfn
, nr_pages
);
1123 while (zone_spans_last_pfn(z
, pfn
, nr_pages
)) {
1124 if (pfn_range_valid_gigantic(z
, pfn
, nr_pages
)) {
1126 * We release the zone lock here because
1127 * alloc_contig_range() will also lock the zone
1128 * at some point. If there's an allocation
1129 * spinning on this lock, it may win the race
1130 * and cause alloc_contig_range() to fail...
1132 spin_unlock_irqrestore(&z
->lock
, flags
);
1133 ret
= __alloc_gigantic_page(pfn
, nr_pages
);
1135 return pfn_to_page(pfn
);
1136 spin_lock_irqsave(&z
->lock
, flags
);
1141 spin_unlock_irqrestore(&z
->lock
, flags
);
1147 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1148 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1150 static struct page
*alloc_fresh_gigantic_page_node(struct hstate
*h
, int nid
)
1154 page
= alloc_gigantic_page(nid
, huge_page_order(h
));
1156 prep_compound_gigantic_page(page
, huge_page_order(h
));
1157 prep_new_huge_page(h
, page
, nid
);
1163 static int alloc_fresh_gigantic_page(struct hstate
*h
,
1164 nodemask_t
*nodes_allowed
)
1166 struct page
*page
= NULL
;
1169 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1170 page
= alloc_fresh_gigantic_page_node(h
, node
);
1178 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1179 static inline bool gigantic_page_supported(void) { return false; }
1180 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1181 static inline void destroy_compound_gigantic_page(struct page
*page
,
1182 unsigned int order
) { }
1183 static inline int alloc_fresh_gigantic_page(struct hstate
*h
,
1184 nodemask_t
*nodes_allowed
) { return 0; }
1187 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1191 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
1195 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1196 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1197 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1198 1 << PG_referenced
| 1 << PG_dirty
|
1199 1 << PG_active
| 1 << PG_private
|
1202 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1203 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1204 set_page_refcounted(page
);
1205 if (hstate_is_gigantic(h
)) {
1206 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1207 free_gigantic_page(page
, huge_page_order(h
));
1209 __free_pages(page
, huge_page_order(h
));
1213 struct hstate
*size_to_hstate(unsigned long size
)
1217 for_each_hstate(h
) {
1218 if (huge_page_size(h
) == size
)
1225 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1226 * to hstate->hugepage_activelist.)
1228 * This function can be called for tail pages, but never returns true for them.
1230 bool page_huge_active(struct page
*page
)
1232 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1233 return PageHead(page
) && PagePrivate(&page
[1]);
1236 /* never called for tail page */
1237 static void set_page_huge_active(struct page
*page
)
1239 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1240 SetPagePrivate(&page
[1]);
1243 static void clear_page_huge_active(struct page
*page
)
1245 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1246 ClearPagePrivate(&page
[1]);
1249 void free_huge_page(struct page
*page
)
1252 * Can't pass hstate in here because it is called from the
1253 * compound page destructor.
1255 struct hstate
*h
= page_hstate(page
);
1256 int nid
= page_to_nid(page
);
1257 struct hugepage_subpool
*spool
=
1258 (struct hugepage_subpool
*)page_private(page
);
1259 bool restore_reserve
;
1261 set_page_private(page
, 0);
1262 page
->mapping
= NULL
;
1263 VM_BUG_ON_PAGE(page_count(page
), page
);
1264 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1265 restore_reserve
= PagePrivate(page
);
1266 ClearPagePrivate(page
);
1269 * A return code of zero implies that the subpool will be under its
1270 * minimum size if the reservation is not restored after page is free.
1271 * Therefore, force restore_reserve operation.
1273 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1274 restore_reserve
= true;
1276 spin_lock(&hugetlb_lock
);
1277 clear_page_huge_active(page
);
1278 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1279 pages_per_huge_page(h
), page
);
1280 if (restore_reserve
)
1281 h
->resv_huge_pages
++;
1283 if (h
->surplus_huge_pages_node
[nid
]) {
1284 /* remove the page from active list */
1285 list_del(&page
->lru
);
1286 update_and_free_page(h
, page
);
1287 h
->surplus_huge_pages
--;
1288 h
->surplus_huge_pages_node
[nid
]--;
1290 arch_clear_hugepage_flags(page
);
1291 enqueue_huge_page(h
, page
);
1293 spin_unlock(&hugetlb_lock
);
1296 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1298 INIT_LIST_HEAD(&page
->lru
);
1299 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1300 spin_lock(&hugetlb_lock
);
1301 set_hugetlb_cgroup(page
, NULL
);
1303 h
->nr_huge_pages_node
[nid
]++;
1304 spin_unlock(&hugetlb_lock
);
1305 put_page(page
); /* free it into the hugepage allocator */
1308 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1311 int nr_pages
= 1 << order
;
1312 struct page
*p
= page
+ 1;
1314 /* we rely on prep_new_huge_page to set the destructor */
1315 set_compound_order(page
, order
);
1316 __ClearPageReserved(page
);
1317 __SetPageHead(page
);
1318 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1320 * For gigantic hugepages allocated through bootmem at
1321 * boot, it's safer to be consistent with the not-gigantic
1322 * hugepages and clear the PG_reserved bit from all tail pages
1323 * too. Otherwse drivers using get_user_pages() to access tail
1324 * pages may get the reference counting wrong if they see
1325 * PG_reserved set on a tail page (despite the head page not
1326 * having PG_reserved set). Enforcing this consistency between
1327 * head and tail pages allows drivers to optimize away a check
1328 * on the head page when they need know if put_page() is needed
1329 * after get_user_pages().
1331 __ClearPageReserved(p
);
1332 set_page_count(p
, 0);
1333 set_compound_head(p
, page
);
1335 atomic_set(compound_mapcount_ptr(page
), -1);
1339 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1340 * transparent huge pages. See the PageTransHuge() documentation for more
1343 int PageHuge(struct page
*page
)
1345 if (!PageCompound(page
))
1348 page
= compound_head(page
);
1349 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1351 EXPORT_SYMBOL_GPL(PageHuge
);
1354 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1355 * normal or transparent huge pages.
1357 int PageHeadHuge(struct page
*page_head
)
1359 if (!PageHead(page_head
))
1362 return get_compound_page_dtor(page_head
) == free_huge_page
;
1365 pgoff_t
__basepage_index(struct page
*page
)
1367 struct page
*page_head
= compound_head(page
);
1368 pgoff_t index
= page_index(page_head
);
1369 unsigned long compound_idx
;
1371 if (!PageHuge(page_head
))
1372 return page_index(page
);
1374 if (compound_order(page_head
) >= MAX_ORDER
)
1375 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1377 compound_idx
= page
- page_head
;
1379 return (index
<< compound_order(page_head
)) + compound_idx
;
1382 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
1386 page
= __alloc_pages_node(nid
,
1387 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
1388 __GFP_REPEAT
|__GFP_NOWARN
,
1389 huge_page_order(h
));
1391 prep_new_huge_page(h
, page
, nid
);
1397 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1403 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1404 page
= alloc_fresh_huge_page_node(h
, node
);
1412 count_vm_event(HTLB_BUDDY_PGALLOC
);
1414 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1420 * Free huge page from pool from next node to free.
1421 * Attempt to keep persistent huge pages more or less
1422 * balanced over allowed nodes.
1423 * Called with hugetlb_lock locked.
1425 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1431 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1433 * If we're returning unused surplus pages, only examine
1434 * nodes with surplus pages.
1436 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1437 !list_empty(&h
->hugepage_freelists
[node
])) {
1439 list_entry(h
->hugepage_freelists
[node
].next
,
1441 list_del(&page
->lru
);
1442 h
->free_huge_pages
--;
1443 h
->free_huge_pages_node
[node
]--;
1445 h
->surplus_huge_pages
--;
1446 h
->surplus_huge_pages_node
[node
]--;
1448 update_and_free_page(h
, page
);
1458 * Dissolve a given free hugepage into free buddy pages. This function does
1459 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1460 * number of free hugepages would be reduced below the number of reserved
1463 static int dissolve_free_huge_page(struct page
*page
)
1467 spin_lock(&hugetlb_lock
);
1468 if (PageHuge(page
) && !page_count(page
)) {
1469 struct page
*head
= compound_head(page
);
1470 struct hstate
*h
= page_hstate(head
);
1471 int nid
= page_to_nid(head
);
1472 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0) {
1476 list_del(&head
->lru
);
1477 h
->free_huge_pages
--;
1478 h
->free_huge_pages_node
[nid
]--;
1479 h
->max_huge_pages
--;
1480 update_and_free_page(h
, head
);
1483 spin_unlock(&hugetlb_lock
);
1488 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1489 * make specified memory blocks removable from the system.
1490 * Note that this will dissolve a free gigantic hugepage completely, if any
1491 * part of it lies within the given range.
1492 * Also note that if dissolve_free_huge_page() returns with an error, all
1493 * free hugepages that were dissolved before that error are lost.
1495 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1501 if (!hugepages_supported())
1504 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1505 page
= pfn_to_page(pfn
);
1506 if (PageHuge(page
) && !page_count(page
)) {
1507 rc
= dissolve_free_huge_page(page
);
1517 * There are 3 ways this can get called:
1518 * 1. With vma+addr: we use the VMA's memory policy
1519 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1520 * page from any node, and let the buddy allocator itself figure
1522 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1523 * strictly from 'nid'
1525 static struct page
*__hugetlb_alloc_buddy_huge_page(struct hstate
*h
,
1526 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1528 int order
= huge_page_order(h
);
1529 gfp_t gfp
= htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_REPEAT
|__GFP_NOWARN
;
1530 unsigned int cpuset_mems_cookie
;
1533 * We need a VMA to get a memory policy. If we do not
1534 * have one, we use the 'nid' argument.
1536 * The mempolicy stuff below has some non-inlined bits
1537 * and calls ->vm_ops. That makes it hard to optimize at
1538 * compile-time, even when NUMA is off and it does
1539 * nothing. This helps the compiler optimize it out.
1541 if (!IS_ENABLED(CONFIG_NUMA
) || !vma
) {
1543 * If a specific node is requested, make sure to
1544 * get memory from there, but only when a node
1545 * is explicitly specified.
1547 if (nid
!= NUMA_NO_NODE
)
1548 gfp
|= __GFP_THISNODE
;
1550 * Make sure to call something that can handle
1553 return alloc_pages_node(nid
, gfp
, order
);
1557 * OK, so we have a VMA. Fetch the mempolicy and try to
1558 * allocate a huge page with it. We will only reach this
1559 * when CONFIG_NUMA=y.
1563 struct mempolicy
*mpol
;
1565 nodemask_t
*nodemask
;
1567 cpuset_mems_cookie
= read_mems_allowed_begin();
1568 nid
= huge_node(vma
, addr
, gfp
, &mpol
, &nodemask
);
1569 mpol_cond_put(mpol
);
1570 page
= __alloc_pages_nodemask(gfp
, order
, nid
, nodemask
);
1573 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1579 * There are two ways to allocate a huge page:
1580 * 1. When you have a VMA and an address (like a fault)
1581 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1583 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1584 * this case which signifies that the allocation should be done with
1585 * respect for the VMA's memory policy.
1587 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1588 * implies that memory policies will not be taken in to account.
1590 static struct page
*__alloc_buddy_huge_page(struct hstate
*h
,
1591 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1596 if (hstate_is_gigantic(h
))
1600 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1601 * This makes sure the caller is picking _one_ of the modes with which
1602 * we can call this function, not both.
1604 if (vma
|| (addr
!= -1)) {
1605 VM_WARN_ON_ONCE(addr
== -1);
1606 VM_WARN_ON_ONCE(nid
!= NUMA_NO_NODE
);
1609 * Assume we will successfully allocate the surplus page to
1610 * prevent racing processes from causing the surplus to exceed
1613 * This however introduces a different race, where a process B
1614 * tries to grow the static hugepage pool while alloc_pages() is
1615 * called by process A. B will only examine the per-node
1616 * counters in determining if surplus huge pages can be
1617 * converted to normal huge pages in adjust_pool_surplus(). A
1618 * won't be able to increment the per-node counter, until the
1619 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1620 * no more huge pages can be converted from surplus to normal
1621 * state (and doesn't try to convert again). Thus, we have a
1622 * case where a surplus huge page exists, the pool is grown, and
1623 * the surplus huge page still exists after, even though it
1624 * should just have been converted to a normal huge page. This
1625 * does not leak memory, though, as the hugepage will be freed
1626 * once it is out of use. It also does not allow the counters to
1627 * go out of whack in adjust_pool_surplus() as we don't modify
1628 * the node values until we've gotten the hugepage and only the
1629 * per-node value is checked there.
1631 spin_lock(&hugetlb_lock
);
1632 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1633 spin_unlock(&hugetlb_lock
);
1637 h
->surplus_huge_pages
++;
1639 spin_unlock(&hugetlb_lock
);
1641 page
= __hugetlb_alloc_buddy_huge_page(h
, vma
, addr
, nid
);
1643 spin_lock(&hugetlb_lock
);
1645 INIT_LIST_HEAD(&page
->lru
);
1646 r_nid
= page_to_nid(page
);
1647 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1648 set_hugetlb_cgroup(page
, NULL
);
1650 * We incremented the global counters already
1652 h
->nr_huge_pages_node
[r_nid
]++;
1653 h
->surplus_huge_pages_node
[r_nid
]++;
1654 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1657 h
->surplus_huge_pages
--;
1658 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1660 spin_unlock(&hugetlb_lock
);
1666 * Allocate a huge page from 'nid'. Note, 'nid' may be
1667 * NUMA_NO_NODE, which means that it may be allocated
1671 struct page
*__alloc_buddy_huge_page_no_mpol(struct hstate
*h
, int nid
)
1673 unsigned long addr
= -1;
1675 return __alloc_buddy_huge_page(h
, NULL
, addr
, nid
);
1679 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1682 struct page
*__alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1683 struct vm_area_struct
*vma
, unsigned long addr
)
1685 return __alloc_buddy_huge_page(h
, vma
, addr
, NUMA_NO_NODE
);
1689 * This allocation function is useful in the context where vma is irrelevant.
1690 * E.g. soft-offlining uses this function because it only cares physical
1691 * address of error page.
1693 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1695 struct page
*page
= NULL
;
1697 spin_lock(&hugetlb_lock
);
1698 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1699 page
= dequeue_huge_page_node(h
, nid
);
1700 spin_unlock(&hugetlb_lock
);
1703 page
= __alloc_buddy_huge_page_no_mpol(h
, nid
);
1709 * Increase the hugetlb pool such that it can accommodate a reservation
1712 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1714 struct list_head surplus_list
;
1715 struct page
*page
, *tmp
;
1717 int needed
, allocated
;
1718 bool alloc_ok
= true;
1720 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1722 h
->resv_huge_pages
+= delta
;
1727 INIT_LIST_HEAD(&surplus_list
);
1731 spin_unlock(&hugetlb_lock
);
1732 for (i
= 0; i
< needed
; i
++) {
1733 page
= __alloc_buddy_huge_page_no_mpol(h
, NUMA_NO_NODE
);
1738 list_add(&page
->lru
, &surplus_list
);
1743 * After retaking hugetlb_lock, we need to recalculate 'needed'
1744 * because either resv_huge_pages or free_huge_pages may have changed.
1746 spin_lock(&hugetlb_lock
);
1747 needed
= (h
->resv_huge_pages
+ delta
) -
1748 (h
->free_huge_pages
+ allocated
);
1753 * We were not able to allocate enough pages to
1754 * satisfy the entire reservation so we free what
1755 * we've allocated so far.
1760 * The surplus_list now contains _at_least_ the number of extra pages
1761 * needed to accommodate the reservation. Add the appropriate number
1762 * of pages to the hugetlb pool and free the extras back to the buddy
1763 * allocator. Commit the entire reservation here to prevent another
1764 * process from stealing the pages as they are added to the pool but
1765 * before they are reserved.
1767 needed
+= allocated
;
1768 h
->resv_huge_pages
+= delta
;
1771 /* Free the needed pages to the hugetlb pool */
1772 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1776 * This page is now managed by the hugetlb allocator and has
1777 * no users -- drop the buddy allocator's reference.
1779 put_page_testzero(page
);
1780 VM_BUG_ON_PAGE(page_count(page
), page
);
1781 enqueue_huge_page(h
, page
);
1784 spin_unlock(&hugetlb_lock
);
1786 /* Free unnecessary surplus pages to the buddy allocator */
1787 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1789 spin_lock(&hugetlb_lock
);
1795 * This routine has two main purposes:
1796 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1797 * in unused_resv_pages. This corresponds to the prior adjustments made
1798 * to the associated reservation map.
1799 * 2) Free any unused surplus pages that may have been allocated to satisfy
1800 * the reservation. As many as unused_resv_pages may be freed.
1802 * Called with hugetlb_lock held. However, the lock could be dropped (and
1803 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1804 * we must make sure nobody else can claim pages we are in the process of
1805 * freeing. Do this by ensuring resv_huge_page always is greater than the
1806 * number of huge pages we plan to free when dropping the lock.
1808 static void return_unused_surplus_pages(struct hstate
*h
,
1809 unsigned long unused_resv_pages
)
1811 unsigned long nr_pages
;
1813 /* Cannot return gigantic pages currently */
1814 if (hstate_is_gigantic(h
))
1818 * Part (or even all) of the reservation could have been backed
1819 * by pre-allocated pages. Only free surplus pages.
1821 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1824 * We want to release as many surplus pages as possible, spread
1825 * evenly across all nodes with memory. Iterate across these nodes
1826 * until we can no longer free unreserved surplus pages. This occurs
1827 * when the nodes with surplus pages have no free pages.
1828 * free_pool_huge_page() will balance the the freed pages across the
1829 * on-line nodes with memory and will handle the hstate accounting.
1831 * Note that we decrement resv_huge_pages as we free the pages. If
1832 * we drop the lock, resv_huge_pages will still be sufficiently large
1833 * to cover subsequent pages we may free.
1835 while (nr_pages
--) {
1836 h
->resv_huge_pages
--;
1837 unused_resv_pages
--;
1838 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1840 cond_resched_lock(&hugetlb_lock
);
1844 /* Fully uncommit the reservation */
1845 h
->resv_huge_pages
-= unused_resv_pages
;
1850 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1851 * are used by the huge page allocation routines to manage reservations.
1853 * vma_needs_reservation is called to determine if the huge page at addr
1854 * within the vma has an associated reservation. If a reservation is
1855 * needed, the value 1 is returned. The caller is then responsible for
1856 * managing the global reservation and subpool usage counts. After
1857 * the huge page has been allocated, vma_commit_reservation is called
1858 * to add the page to the reservation map. If the page allocation fails,
1859 * the reservation must be ended instead of committed. vma_end_reservation
1860 * is called in such cases.
1862 * In the normal case, vma_commit_reservation returns the same value
1863 * as the preceding vma_needs_reservation call. The only time this
1864 * is not the case is if a reserve map was changed between calls. It
1865 * is the responsibility of the caller to notice the difference and
1866 * take appropriate action.
1868 * vma_add_reservation is used in error paths where a reservation must
1869 * be restored when a newly allocated huge page must be freed. It is
1870 * to be called after calling vma_needs_reservation to determine if a
1871 * reservation exists.
1873 enum vma_resv_mode
{
1879 static long __vma_reservation_common(struct hstate
*h
,
1880 struct vm_area_struct
*vma
, unsigned long addr
,
1881 enum vma_resv_mode mode
)
1883 struct resv_map
*resv
;
1887 resv
= vma_resv_map(vma
);
1891 idx
= vma_hugecache_offset(h
, vma
, addr
);
1893 case VMA_NEEDS_RESV
:
1894 ret
= region_chg(resv
, idx
, idx
+ 1);
1896 case VMA_COMMIT_RESV
:
1897 ret
= region_add(resv
, idx
, idx
+ 1);
1900 region_abort(resv
, idx
, idx
+ 1);
1904 if (vma
->vm_flags
& VM_MAYSHARE
)
1905 ret
= region_add(resv
, idx
, idx
+ 1);
1907 region_abort(resv
, idx
, idx
+ 1);
1908 ret
= region_del(resv
, idx
, idx
+ 1);
1915 if (vma
->vm_flags
& VM_MAYSHARE
)
1917 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
1919 * In most cases, reserves always exist for private mappings.
1920 * However, a file associated with mapping could have been
1921 * hole punched or truncated after reserves were consumed.
1922 * As subsequent fault on such a range will not use reserves.
1923 * Subtle - The reserve map for private mappings has the
1924 * opposite meaning than that of shared mappings. If NO
1925 * entry is in the reserve map, it means a reservation exists.
1926 * If an entry exists in the reserve map, it means the
1927 * reservation has already been consumed. As a result, the
1928 * return value of this routine is the opposite of the
1929 * value returned from reserve map manipulation routines above.
1937 return ret
< 0 ? ret
: 0;
1940 static long vma_needs_reservation(struct hstate
*h
,
1941 struct vm_area_struct
*vma
, unsigned long addr
)
1943 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
1946 static long vma_commit_reservation(struct hstate
*h
,
1947 struct vm_area_struct
*vma
, unsigned long addr
)
1949 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
1952 static void vma_end_reservation(struct hstate
*h
,
1953 struct vm_area_struct
*vma
, unsigned long addr
)
1955 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
1958 static long vma_add_reservation(struct hstate
*h
,
1959 struct vm_area_struct
*vma
, unsigned long addr
)
1961 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
1965 * This routine is called to restore a reservation on error paths. In the
1966 * specific error paths, a huge page was allocated (via alloc_huge_page)
1967 * and is about to be freed. If a reservation for the page existed,
1968 * alloc_huge_page would have consumed the reservation and set PagePrivate
1969 * in the newly allocated page. When the page is freed via free_huge_page,
1970 * the global reservation count will be incremented if PagePrivate is set.
1971 * However, free_huge_page can not adjust the reserve map. Adjust the
1972 * reserve map here to be consistent with global reserve count adjustments
1973 * to be made by free_huge_page.
1975 static void restore_reserve_on_error(struct hstate
*h
,
1976 struct vm_area_struct
*vma
, unsigned long address
,
1979 if (unlikely(PagePrivate(page
))) {
1980 long rc
= vma_needs_reservation(h
, vma
, address
);
1982 if (unlikely(rc
< 0)) {
1984 * Rare out of memory condition in reserve map
1985 * manipulation. Clear PagePrivate so that
1986 * global reserve count will not be incremented
1987 * by free_huge_page. This will make it appear
1988 * as though the reservation for this page was
1989 * consumed. This may prevent the task from
1990 * faulting in the page at a later time. This
1991 * is better than inconsistent global huge page
1992 * accounting of reserve counts.
1994 ClearPagePrivate(page
);
1996 rc
= vma_add_reservation(h
, vma
, address
);
1997 if (unlikely(rc
< 0))
1999 * See above comment about rare out of
2002 ClearPagePrivate(page
);
2004 vma_end_reservation(h
, vma
, address
);
2008 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2009 unsigned long addr
, int avoid_reserve
)
2011 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2012 struct hstate
*h
= hstate_vma(vma
);
2014 long map_chg
, map_commit
;
2017 struct hugetlb_cgroup
*h_cg
;
2019 idx
= hstate_index(h
);
2021 * Examine the region/reserve map to determine if the process
2022 * has a reservation for the page to be allocated. A return
2023 * code of zero indicates a reservation exists (no change).
2025 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2027 return ERR_PTR(-ENOMEM
);
2030 * Processes that did not create the mapping will have no
2031 * reserves as indicated by the region/reserve map. Check
2032 * that the allocation will not exceed the subpool limit.
2033 * Allocations for MAP_NORESERVE mappings also need to be
2034 * checked against any subpool limit.
2036 if (map_chg
|| avoid_reserve
) {
2037 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2039 vma_end_reservation(h
, vma
, addr
);
2040 return ERR_PTR(-ENOSPC
);
2044 * Even though there was no reservation in the region/reserve
2045 * map, there could be reservations associated with the
2046 * subpool that can be used. This would be indicated if the
2047 * return value of hugepage_subpool_get_pages() is zero.
2048 * However, if avoid_reserve is specified we still avoid even
2049 * the subpool reservations.
2055 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2057 goto out_subpool_put
;
2059 spin_lock(&hugetlb_lock
);
2061 * glb_chg is passed to indicate whether or not a page must be taken
2062 * from the global free pool (global change). gbl_chg == 0 indicates
2063 * a reservation exists for the allocation.
2065 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2067 spin_unlock(&hugetlb_lock
);
2068 page
= __alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2070 goto out_uncharge_cgroup
;
2071 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2072 SetPagePrivate(page
);
2073 h
->resv_huge_pages
--;
2075 spin_lock(&hugetlb_lock
);
2076 list_move(&page
->lru
, &h
->hugepage_activelist
);
2079 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2080 spin_unlock(&hugetlb_lock
);
2082 set_page_private(page
, (unsigned long)spool
);
2084 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2085 if (unlikely(map_chg
> map_commit
)) {
2087 * The page was added to the reservation map between
2088 * vma_needs_reservation and vma_commit_reservation.
2089 * This indicates a race with hugetlb_reserve_pages.
2090 * Adjust for the subpool count incremented above AND
2091 * in hugetlb_reserve_pages for the same page. Also,
2092 * the reservation count added in hugetlb_reserve_pages
2093 * no longer applies.
2097 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2098 hugetlb_acct_memory(h
, -rsv_adjust
);
2102 out_uncharge_cgroup
:
2103 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2105 if (map_chg
|| avoid_reserve
)
2106 hugepage_subpool_put_pages(spool
, 1);
2107 vma_end_reservation(h
, vma
, addr
);
2108 return ERR_PTR(-ENOSPC
);
2112 * alloc_huge_page()'s wrapper which simply returns the page if allocation
2113 * succeeds, otherwise NULL. This function is called from new_vma_page(),
2114 * where no ERR_VALUE is expected to be returned.
2116 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
2117 unsigned long addr
, int avoid_reserve
)
2119 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
2125 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
2127 struct huge_bootmem_page
*m
;
2130 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2133 addr
= memblock_virt_alloc_try_nid_nopanic(
2134 huge_page_size(h
), huge_page_size(h
),
2135 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
2138 * Use the beginning of the huge page to store the
2139 * huge_bootmem_page struct (until gather_bootmem
2140 * puts them into the mem_map).
2149 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2150 /* Put them into a private list first because mem_map is not up yet */
2151 list_add(&m
->list
, &huge_boot_pages
);
2156 static void __init
prep_compound_huge_page(struct page
*page
,
2159 if (unlikely(order
> (MAX_ORDER
- 1)))
2160 prep_compound_gigantic_page(page
, order
);
2162 prep_compound_page(page
, order
);
2165 /* Put bootmem huge pages into the standard lists after mem_map is up */
2166 static void __init
gather_bootmem_prealloc(void)
2168 struct huge_bootmem_page
*m
;
2170 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2171 struct hstate
*h
= m
->hstate
;
2174 #ifdef CONFIG_HIGHMEM
2175 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
2176 memblock_free_late(__pa(m
),
2177 sizeof(struct huge_bootmem_page
));
2179 page
= virt_to_page(m
);
2181 WARN_ON(page_count(page
) != 1);
2182 prep_compound_huge_page(page
, h
->order
);
2183 WARN_ON(PageReserved(page
));
2184 prep_new_huge_page(h
, page
, page_to_nid(page
));
2186 * If we had gigantic hugepages allocated at boot time, we need
2187 * to restore the 'stolen' pages to totalram_pages in order to
2188 * fix confusing memory reports from free(1) and another
2189 * side-effects, like CommitLimit going negative.
2191 if (hstate_is_gigantic(h
))
2192 adjust_managed_page_count(page
, 1 << h
->order
);
2196 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2200 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2201 if (hstate_is_gigantic(h
)) {
2202 if (!alloc_bootmem_huge_page(h
))
2204 } else if (!alloc_fresh_huge_page(h
,
2205 &node_states
[N_MEMORY
]))
2208 h
->max_huge_pages
= i
;
2211 static void __init
hugetlb_init_hstates(void)
2215 for_each_hstate(h
) {
2216 if (minimum_order
> huge_page_order(h
))
2217 minimum_order
= huge_page_order(h
);
2219 /* oversize hugepages were init'ed in early boot */
2220 if (!hstate_is_gigantic(h
))
2221 hugetlb_hstate_alloc_pages(h
);
2223 VM_BUG_ON(minimum_order
== UINT_MAX
);
2226 static char * __init
memfmt(char *buf
, unsigned long n
)
2228 if (n
>= (1UL << 30))
2229 sprintf(buf
, "%lu GB", n
>> 30);
2230 else if (n
>= (1UL << 20))
2231 sprintf(buf
, "%lu MB", n
>> 20);
2233 sprintf(buf
, "%lu KB", n
>> 10);
2237 static void __init
report_hugepages(void)
2241 for_each_hstate(h
) {
2243 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2244 memfmt(buf
, huge_page_size(h
)),
2245 h
->free_huge_pages
);
2249 #ifdef CONFIG_HIGHMEM
2250 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2251 nodemask_t
*nodes_allowed
)
2255 if (hstate_is_gigantic(h
))
2258 for_each_node_mask(i
, *nodes_allowed
) {
2259 struct page
*page
, *next
;
2260 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2261 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2262 if (count
>= h
->nr_huge_pages
)
2264 if (PageHighMem(page
))
2266 list_del(&page
->lru
);
2267 update_and_free_page(h
, page
);
2268 h
->free_huge_pages
--;
2269 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2274 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2275 nodemask_t
*nodes_allowed
)
2281 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2282 * balanced by operating on them in a round-robin fashion.
2283 * Returns 1 if an adjustment was made.
2285 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2290 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2293 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2294 if (h
->surplus_huge_pages_node
[node
])
2298 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2299 if (h
->surplus_huge_pages_node
[node
] <
2300 h
->nr_huge_pages_node
[node
])
2307 h
->surplus_huge_pages
+= delta
;
2308 h
->surplus_huge_pages_node
[node
] += delta
;
2312 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2313 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
2314 nodemask_t
*nodes_allowed
)
2316 unsigned long min_count
, ret
;
2318 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
2319 return h
->max_huge_pages
;
2322 * Increase the pool size
2323 * First take pages out of surplus state. Then make up the
2324 * remaining difference by allocating fresh huge pages.
2326 * We might race with __alloc_buddy_huge_page() here and be unable
2327 * to convert a surplus huge page to a normal huge page. That is
2328 * not critical, though, it just means the overall size of the
2329 * pool might be one hugepage larger than it needs to be, but
2330 * within all the constraints specified by the sysctls.
2332 spin_lock(&hugetlb_lock
);
2333 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2334 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2338 while (count
> persistent_huge_pages(h
)) {
2340 * If this allocation races such that we no longer need the
2341 * page, free_huge_page will handle it by freeing the page
2342 * and reducing the surplus.
2344 spin_unlock(&hugetlb_lock
);
2346 /* yield cpu to avoid soft lockup */
2349 if (hstate_is_gigantic(h
))
2350 ret
= alloc_fresh_gigantic_page(h
, nodes_allowed
);
2352 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
2353 spin_lock(&hugetlb_lock
);
2357 /* Bail for signals. Probably ctrl-c from user */
2358 if (signal_pending(current
))
2363 * Decrease the pool size
2364 * First return free pages to the buddy allocator (being careful
2365 * to keep enough around to satisfy reservations). Then place
2366 * pages into surplus state as needed so the pool will shrink
2367 * to the desired size as pages become free.
2369 * By placing pages into the surplus state independent of the
2370 * overcommit value, we are allowing the surplus pool size to
2371 * exceed overcommit. There are few sane options here. Since
2372 * __alloc_buddy_huge_page() is checking the global counter,
2373 * though, we'll note that we're not allowed to exceed surplus
2374 * and won't grow the pool anywhere else. Not until one of the
2375 * sysctls are changed, or the surplus pages go out of use.
2377 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2378 min_count
= max(count
, min_count
);
2379 try_to_free_low(h
, min_count
, nodes_allowed
);
2380 while (min_count
< persistent_huge_pages(h
)) {
2381 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2383 cond_resched_lock(&hugetlb_lock
);
2385 while (count
< persistent_huge_pages(h
)) {
2386 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2390 ret
= persistent_huge_pages(h
);
2391 spin_unlock(&hugetlb_lock
);
2395 #define HSTATE_ATTR_RO(_name) \
2396 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2398 #define HSTATE_ATTR(_name) \
2399 static struct kobj_attribute _name##_attr = \
2400 __ATTR(_name, 0644, _name##_show, _name##_store)
2402 static struct kobject
*hugepages_kobj
;
2403 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2405 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2407 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2411 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2412 if (hstate_kobjs
[i
] == kobj
) {
2414 *nidp
= NUMA_NO_NODE
;
2418 return kobj_to_node_hstate(kobj
, nidp
);
2421 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2422 struct kobj_attribute
*attr
, char *buf
)
2425 unsigned long nr_huge_pages
;
2428 h
= kobj_to_hstate(kobj
, &nid
);
2429 if (nid
== NUMA_NO_NODE
)
2430 nr_huge_pages
= h
->nr_huge_pages
;
2432 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2434 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2437 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2438 struct hstate
*h
, int nid
,
2439 unsigned long count
, size_t len
)
2442 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
2444 if (hstate_is_gigantic(h
) && !gigantic_page_supported()) {
2449 if (nid
== NUMA_NO_NODE
) {
2451 * global hstate attribute
2453 if (!(obey_mempolicy
&&
2454 init_nodemask_of_mempolicy(nodes_allowed
))) {
2455 NODEMASK_FREE(nodes_allowed
);
2456 nodes_allowed
= &node_states
[N_MEMORY
];
2458 } else if (nodes_allowed
) {
2460 * per node hstate attribute: adjust count to global,
2461 * but restrict alloc/free to the specified node.
2463 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2464 init_nodemask_of_node(nodes_allowed
, nid
);
2466 nodes_allowed
= &node_states
[N_MEMORY
];
2468 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
2470 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2471 NODEMASK_FREE(nodes_allowed
);
2475 NODEMASK_FREE(nodes_allowed
);
2479 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2480 struct kobject
*kobj
, const char *buf
,
2484 unsigned long count
;
2488 err
= kstrtoul(buf
, 10, &count
);
2492 h
= kobj_to_hstate(kobj
, &nid
);
2493 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2496 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2497 struct kobj_attribute
*attr
, char *buf
)
2499 return nr_hugepages_show_common(kobj
, attr
, buf
);
2502 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2503 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2505 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2507 HSTATE_ATTR(nr_hugepages
);
2512 * hstate attribute for optionally mempolicy-based constraint on persistent
2513 * huge page alloc/free.
2515 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2516 struct kobj_attribute
*attr
, char *buf
)
2518 return nr_hugepages_show_common(kobj
, attr
, buf
);
2521 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2522 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2524 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2526 HSTATE_ATTR(nr_hugepages_mempolicy
);
2530 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2531 struct kobj_attribute
*attr
, char *buf
)
2533 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2534 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2537 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2538 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2541 unsigned long input
;
2542 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2544 if (hstate_is_gigantic(h
))
2547 err
= kstrtoul(buf
, 10, &input
);
2551 spin_lock(&hugetlb_lock
);
2552 h
->nr_overcommit_huge_pages
= input
;
2553 spin_unlock(&hugetlb_lock
);
2557 HSTATE_ATTR(nr_overcommit_hugepages
);
2559 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2560 struct kobj_attribute
*attr
, char *buf
)
2563 unsigned long free_huge_pages
;
2566 h
= kobj_to_hstate(kobj
, &nid
);
2567 if (nid
== NUMA_NO_NODE
)
2568 free_huge_pages
= h
->free_huge_pages
;
2570 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2572 return sprintf(buf
, "%lu\n", free_huge_pages
);
2574 HSTATE_ATTR_RO(free_hugepages
);
2576 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2577 struct kobj_attribute
*attr
, char *buf
)
2579 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2580 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2582 HSTATE_ATTR_RO(resv_hugepages
);
2584 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2585 struct kobj_attribute
*attr
, char *buf
)
2588 unsigned long surplus_huge_pages
;
2591 h
= kobj_to_hstate(kobj
, &nid
);
2592 if (nid
== NUMA_NO_NODE
)
2593 surplus_huge_pages
= h
->surplus_huge_pages
;
2595 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2597 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2599 HSTATE_ATTR_RO(surplus_hugepages
);
2601 static struct attribute
*hstate_attrs
[] = {
2602 &nr_hugepages_attr
.attr
,
2603 &nr_overcommit_hugepages_attr
.attr
,
2604 &free_hugepages_attr
.attr
,
2605 &resv_hugepages_attr
.attr
,
2606 &surplus_hugepages_attr
.attr
,
2608 &nr_hugepages_mempolicy_attr
.attr
,
2613 static struct attribute_group hstate_attr_group
= {
2614 .attrs
= hstate_attrs
,
2617 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2618 struct kobject
**hstate_kobjs
,
2619 struct attribute_group
*hstate_attr_group
)
2622 int hi
= hstate_index(h
);
2624 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2625 if (!hstate_kobjs
[hi
])
2628 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2630 kobject_put(hstate_kobjs
[hi
]);
2635 static void __init
hugetlb_sysfs_init(void)
2640 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2641 if (!hugepages_kobj
)
2644 for_each_hstate(h
) {
2645 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2646 hstate_kobjs
, &hstate_attr_group
);
2648 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2655 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2656 * with node devices in node_devices[] using a parallel array. The array
2657 * index of a node device or _hstate == node id.
2658 * This is here to avoid any static dependency of the node device driver, in
2659 * the base kernel, on the hugetlb module.
2661 struct node_hstate
{
2662 struct kobject
*hugepages_kobj
;
2663 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2665 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2668 * A subset of global hstate attributes for node devices
2670 static struct attribute
*per_node_hstate_attrs
[] = {
2671 &nr_hugepages_attr
.attr
,
2672 &free_hugepages_attr
.attr
,
2673 &surplus_hugepages_attr
.attr
,
2677 static struct attribute_group per_node_hstate_attr_group
= {
2678 .attrs
= per_node_hstate_attrs
,
2682 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2683 * Returns node id via non-NULL nidp.
2685 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2689 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2690 struct node_hstate
*nhs
= &node_hstates
[nid
];
2692 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2693 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2705 * Unregister hstate attributes from a single node device.
2706 * No-op if no hstate attributes attached.
2708 static void hugetlb_unregister_node(struct node
*node
)
2711 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2713 if (!nhs
->hugepages_kobj
)
2714 return; /* no hstate attributes */
2716 for_each_hstate(h
) {
2717 int idx
= hstate_index(h
);
2718 if (nhs
->hstate_kobjs
[idx
]) {
2719 kobject_put(nhs
->hstate_kobjs
[idx
]);
2720 nhs
->hstate_kobjs
[idx
] = NULL
;
2724 kobject_put(nhs
->hugepages_kobj
);
2725 nhs
->hugepages_kobj
= NULL
;
2730 * Register hstate attributes for a single node device.
2731 * No-op if attributes already registered.
2733 static void hugetlb_register_node(struct node
*node
)
2736 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2739 if (nhs
->hugepages_kobj
)
2740 return; /* already allocated */
2742 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2744 if (!nhs
->hugepages_kobj
)
2747 for_each_hstate(h
) {
2748 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2750 &per_node_hstate_attr_group
);
2752 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2753 h
->name
, node
->dev
.id
);
2754 hugetlb_unregister_node(node
);
2761 * hugetlb init time: register hstate attributes for all registered node
2762 * devices of nodes that have memory. All on-line nodes should have
2763 * registered their associated device by this time.
2765 static void __init
hugetlb_register_all_nodes(void)
2769 for_each_node_state(nid
, N_MEMORY
) {
2770 struct node
*node
= node_devices
[nid
];
2771 if (node
->dev
.id
== nid
)
2772 hugetlb_register_node(node
);
2776 * Let the node device driver know we're here so it can
2777 * [un]register hstate attributes on node hotplug.
2779 register_hugetlbfs_with_node(hugetlb_register_node
,
2780 hugetlb_unregister_node
);
2782 #else /* !CONFIG_NUMA */
2784 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2792 static void hugetlb_register_all_nodes(void) { }
2796 static int __init
hugetlb_init(void)
2800 if (!hugepages_supported())
2803 if (!size_to_hstate(default_hstate_size
)) {
2804 default_hstate_size
= HPAGE_SIZE
;
2805 if (!size_to_hstate(default_hstate_size
))
2806 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2808 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2809 if (default_hstate_max_huge_pages
) {
2810 if (!default_hstate
.max_huge_pages
)
2811 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2814 hugetlb_init_hstates();
2815 gather_bootmem_prealloc();
2818 hugetlb_sysfs_init();
2819 hugetlb_register_all_nodes();
2820 hugetlb_cgroup_file_init();
2823 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2825 num_fault_mutexes
= 1;
2827 hugetlb_fault_mutex_table
=
2828 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2829 BUG_ON(!hugetlb_fault_mutex_table
);
2831 for (i
= 0; i
< num_fault_mutexes
; i
++)
2832 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2835 subsys_initcall(hugetlb_init
);
2837 /* Should be called on processing a hugepagesz=... option */
2838 void __init
hugetlb_bad_size(void)
2840 parsed_valid_hugepagesz
= false;
2843 void __init
hugetlb_add_hstate(unsigned int order
)
2848 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2849 pr_warn("hugepagesz= specified twice, ignoring\n");
2852 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2854 h
= &hstates
[hugetlb_max_hstate
++];
2856 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2857 h
->nr_huge_pages
= 0;
2858 h
->free_huge_pages
= 0;
2859 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2860 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2861 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2862 h
->next_nid_to_alloc
= first_memory_node
;
2863 h
->next_nid_to_free
= first_memory_node
;
2864 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2865 huge_page_size(h
)/1024);
2870 static int __init
hugetlb_nrpages_setup(char *s
)
2873 static unsigned long *last_mhp
;
2875 if (!parsed_valid_hugepagesz
) {
2876 pr_warn("hugepages = %s preceded by "
2877 "an unsupported hugepagesz, ignoring\n", s
);
2878 parsed_valid_hugepagesz
= true;
2882 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2883 * so this hugepages= parameter goes to the "default hstate".
2885 else if (!hugetlb_max_hstate
)
2886 mhp
= &default_hstate_max_huge_pages
;
2888 mhp
= &parsed_hstate
->max_huge_pages
;
2890 if (mhp
== last_mhp
) {
2891 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2895 if (sscanf(s
, "%lu", mhp
) <= 0)
2899 * Global state is always initialized later in hugetlb_init.
2900 * But we need to allocate >= MAX_ORDER hstates here early to still
2901 * use the bootmem allocator.
2903 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2904 hugetlb_hstate_alloc_pages(parsed_hstate
);
2910 __setup("hugepages=", hugetlb_nrpages_setup
);
2912 static int __init
hugetlb_default_setup(char *s
)
2914 default_hstate_size
= memparse(s
, &s
);
2917 __setup("default_hugepagesz=", hugetlb_default_setup
);
2919 static unsigned int cpuset_mems_nr(unsigned int *array
)
2922 unsigned int nr
= 0;
2924 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2930 #ifdef CONFIG_SYSCTL
2931 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2932 struct ctl_table
*table
, int write
,
2933 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2935 struct hstate
*h
= &default_hstate
;
2936 unsigned long tmp
= h
->max_huge_pages
;
2939 if (!hugepages_supported())
2943 table
->maxlen
= sizeof(unsigned long);
2944 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2949 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
2950 NUMA_NO_NODE
, tmp
, *length
);
2955 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2956 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2959 return hugetlb_sysctl_handler_common(false, table
, write
,
2960 buffer
, length
, ppos
);
2964 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2965 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2967 return hugetlb_sysctl_handler_common(true, table
, write
,
2968 buffer
, length
, ppos
);
2970 #endif /* CONFIG_NUMA */
2972 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2973 void __user
*buffer
,
2974 size_t *length
, loff_t
*ppos
)
2976 struct hstate
*h
= &default_hstate
;
2980 if (!hugepages_supported())
2983 tmp
= h
->nr_overcommit_huge_pages
;
2985 if (write
&& hstate_is_gigantic(h
))
2989 table
->maxlen
= sizeof(unsigned long);
2990 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2995 spin_lock(&hugetlb_lock
);
2996 h
->nr_overcommit_huge_pages
= tmp
;
2997 spin_unlock(&hugetlb_lock
);
3003 #endif /* CONFIG_SYSCTL */
3005 void hugetlb_report_meminfo(struct seq_file
*m
)
3007 struct hstate
*h
= &default_hstate
;
3008 if (!hugepages_supported())
3011 "HugePages_Total: %5lu\n"
3012 "HugePages_Free: %5lu\n"
3013 "HugePages_Rsvd: %5lu\n"
3014 "HugePages_Surp: %5lu\n"
3015 "Hugepagesize: %8lu kB\n",
3019 h
->surplus_huge_pages
,
3020 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3023 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3025 struct hstate
*h
= &default_hstate
;
3026 if (!hugepages_supported())
3029 "Node %d HugePages_Total: %5u\n"
3030 "Node %d HugePages_Free: %5u\n"
3031 "Node %d HugePages_Surp: %5u\n",
3032 nid
, h
->nr_huge_pages_node
[nid
],
3033 nid
, h
->free_huge_pages_node
[nid
],
3034 nid
, h
->surplus_huge_pages_node
[nid
]);
3037 void hugetlb_show_meminfo(void)
3042 if (!hugepages_supported())
3045 for_each_node_state(nid
, N_MEMORY
)
3047 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3049 h
->nr_huge_pages_node
[nid
],
3050 h
->free_huge_pages_node
[nid
],
3051 h
->surplus_huge_pages_node
[nid
],
3052 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3055 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3057 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3058 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3061 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3062 unsigned long hugetlb_total_pages(void)
3065 unsigned long nr_total_pages
= 0;
3068 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3069 return nr_total_pages
;
3072 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3076 spin_lock(&hugetlb_lock
);
3078 * When cpuset is configured, it breaks the strict hugetlb page
3079 * reservation as the accounting is done on a global variable. Such
3080 * reservation is completely rubbish in the presence of cpuset because
3081 * the reservation is not checked against page availability for the
3082 * current cpuset. Application can still potentially OOM'ed by kernel
3083 * with lack of free htlb page in cpuset that the task is in.
3084 * Attempt to enforce strict accounting with cpuset is almost
3085 * impossible (or too ugly) because cpuset is too fluid that
3086 * task or memory node can be dynamically moved between cpusets.
3088 * The change of semantics for shared hugetlb mapping with cpuset is
3089 * undesirable. However, in order to preserve some of the semantics,
3090 * we fall back to check against current free page availability as
3091 * a best attempt and hopefully to minimize the impact of changing
3092 * semantics that cpuset has.
3095 if (gather_surplus_pages(h
, delta
) < 0)
3098 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3099 return_unused_surplus_pages(h
, delta
);
3106 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3109 spin_unlock(&hugetlb_lock
);
3113 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3115 struct resv_map
*resv
= vma_resv_map(vma
);
3118 * This new VMA should share its siblings reservation map if present.
3119 * The VMA will only ever have a valid reservation map pointer where
3120 * it is being copied for another still existing VMA. As that VMA
3121 * has a reference to the reservation map it cannot disappear until
3122 * after this open call completes. It is therefore safe to take a
3123 * new reference here without additional locking.
3125 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3126 kref_get(&resv
->refs
);
3129 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3131 struct hstate
*h
= hstate_vma(vma
);
3132 struct resv_map
*resv
= vma_resv_map(vma
);
3133 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3134 unsigned long reserve
, start
, end
;
3137 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3140 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3141 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3143 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3145 kref_put(&resv
->refs
, resv_map_release
);
3149 * Decrement reserve counts. The global reserve count may be
3150 * adjusted if the subpool has a minimum size.
3152 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3153 hugetlb_acct_memory(h
, -gbl_reserve
);
3158 * We cannot handle pagefaults against hugetlb pages at all. They cause
3159 * handle_mm_fault() to try to instantiate regular-sized pages in the
3160 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3163 static int hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3169 const struct vm_operations_struct hugetlb_vm_ops
= {
3170 .fault
= hugetlb_vm_op_fault
,
3171 .open
= hugetlb_vm_op_open
,
3172 .close
= hugetlb_vm_op_close
,
3175 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3181 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3182 vma
->vm_page_prot
)));
3184 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3185 vma
->vm_page_prot
));
3187 entry
= pte_mkyoung(entry
);
3188 entry
= pte_mkhuge(entry
);
3189 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3194 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3195 unsigned long address
, pte_t
*ptep
)
3199 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3200 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3201 update_mmu_cache(vma
, address
, ptep
);
3204 bool is_hugetlb_entry_migration(pte_t pte
)
3208 if (huge_pte_none(pte
) || pte_present(pte
))
3210 swp
= pte_to_swp_entry(pte
);
3211 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3217 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3221 if (huge_pte_none(pte
) || pte_present(pte
))
3223 swp
= pte_to_swp_entry(pte
);
3224 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3230 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3231 struct vm_area_struct
*vma
)
3233 pte_t
*src_pte
, *dst_pte
, entry
;
3234 struct page
*ptepage
;
3237 struct hstate
*h
= hstate_vma(vma
);
3238 unsigned long sz
= huge_page_size(h
);
3239 unsigned long mmun_start
; /* For mmu_notifiers */
3240 unsigned long mmun_end
; /* For mmu_notifiers */
3243 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3245 mmun_start
= vma
->vm_start
;
3246 mmun_end
= vma
->vm_end
;
3248 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
3250 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3251 spinlock_t
*src_ptl
, *dst_ptl
;
3252 src_pte
= huge_pte_offset(src
, addr
, sz
);
3255 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3261 /* If the pagetables are shared don't copy or take references */
3262 if (dst_pte
== src_pte
)
3265 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3266 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3267 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3268 entry
= huge_ptep_get(src_pte
);
3269 if (huge_pte_none(entry
)) { /* skip none entry */
3271 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3272 is_hugetlb_entry_hwpoisoned(entry
))) {
3273 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3275 if (is_write_migration_entry(swp_entry
) && cow
) {
3277 * COW mappings require pages in both
3278 * parent and child to be set to read.
3280 make_migration_entry_read(&swp_entry
);
3281 entry
= swp_entry_to_pte(swp_entry
);
3282 set_huge_swap_pte_at(src
, addr
, src_pte
,
3285 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3288 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3289 mmu_notifier_invalidate_range(src
, mmun_start
,
3292 entry
= huge_ptep_get(src_pte
);
3293 ptepage
= pte_page(entry
);
3295 page_dup_rmap(ptepage
, true);
3296 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3297 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3299 spin_unlock(src_ptl
);
3300 spin_unlock(dst_ptl
);
3304 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
3309 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3310 unsigned long start
, unsigned long end
,
3311 struct page
*ref_page
)
3313 struct mm_struct
*mm
= vma
->vm_mm
;
3314 unsigned long address
;
3319 struct hstate
*h
= hstate_vma(vma
);
3320 unsigned long sz
= huge_page_size(h
);
3321 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
3322 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
3324 WARN_ON(!is_vm_hugetlb_page(vma
));
3325 BUG_ON(start
& ~huge_page_mask(h
));
3326 BUG_ON(end
& ~huge_page_mask(h
));
3329 * This is a hugetlb vma, all the pte entries should point
3332 tlb_remove_check_page_size_change(tlb
, sz
);
3333 tlb_start_vma(tlb
, vma
);
3334 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3336 for (; address
< end
; address
+= sz
) {
3337 ptep
= huge_pte_offset(mm
, address
, sz
);
3341 ptl
= huge_pte_lock(h
, mm
, ptep
);
3342 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3347 pte
= huge_ptep_get(ptep
);
3348 if (huge_pte_none(pte
)) {
3354 * Migrating hugepage or HWPoisoned hugepage is already
3355 * unmapped and its refcount is dropped, so just clear pte here.
3357 if (unlikely(!pte_present(pte
))) {
3358 huge_pte_clear(mm
, address
, ptep
, sz
);
3363 page
= pte_page(pte
);
3365 * If a reference page is supplied, it is because a specific
3366 * page is being unmapped, not a range. Ensure the page we
3367 * are about to unmap is the actual page of interest.
3370 if (page
!= ref_page
) {
3375 * Mark the VMA as having unmapped its page so that
3376 * future faults in this VMA will fail rather than
3377 * looking like data was lost
3379 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3382 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3383 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3384 if (huge_pte_dirty(pte
))
3385 set_page_dirty(page
);
3387 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3388 page_remove_rmap(page
, true);
3391 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3393 * Bail out after unmapping reference page if supplied
3398 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3399 tlb_end_vma(tlb
, vma
);
3402 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3403 struct vm_area_struct
*vma
, unsigned long start
,
3404 unsigned long end
, struct page
*ref_page
)
3406 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3409 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3410 * test will fail on a vma being torn down, and not grab a page table
3411 * on its way out. We're lucky that the flag has such an appropriate
3412 * name, and can in fact be safely cleared here. We could clear it
3413 * before the __unmap_hugepage_range above, but all that's necessary
3414 * is to clear it before releasing the i_mmap_rwsem. This works
3415 * because in the context this is called, the VMA is about to be
3416 * destroyed and the i_mmap_rwsem is held.
3418 vma
->vm_flags
&= ~VM_MAYSHARE
;
3421 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3422 unsigned long end
, struct page
*ref_page
)
3424 struct mm_struct
*mm
;
3425 struct mmu_gather tlb
;
3429 tlb_gather_mmu(&tlb
, mm
, start
, end
);
3430 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3431 tlb_finish_mmu(&tlb
, start
, end
);
3435 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3436 * mappping it owns the reserve page for. The intention is to unmap the page
3437 * from other VMAs and let the children be SIGKILLed if they are faulting the
3440 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3441 struct page
*page
, unsigned long address
)
3443 struct hstate
*h
= hstate_vma(vma
);
3444 struct vm_area_struct
*iter_vma
;
3445 struct address_space
*mapping
;
3449 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3450 * from page cache lookup which is in HPAGE_SIZE units.
3452 address
= address
& huge_page_mask(h
);
3453 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3455 mapping
= vma
->vm_file
->f_mapping
;
3458 * Take the mapping lock for the duration of the table walk. As
3459 * this mapping should be shared between all the VMAs,
3460 * __unmap_hugepage_range() is called as the lock is already held
3462 i_mmap_lock_write(mapping
);
3463 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3464 /* Do not unmap the current VMA */
3465 if (iter_vma
== vma
)
3469 * Shared VMAs have their own reserves and do not affect
3470 * MAP_PRIVATE accounting but it is possible that a shared
3471 * VMA is using the same page so check and skip such VMAs.
3473 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3477 * Unmap the page from other VMAs without their own reserves.
3478 * They get marked to be SIGKILLed if they fault in these
3479 * areas. This is because a future no-page fault on this VMA
3480 * could insert a zeroed page instead of the data existing
3481 * from the time of fork. This would look like data corruption
3483 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3484 unmap_hugepage_range(iter_vma
, address
,
3485 address
+ huge_page_size(h
), page
);
3487 i_mmap_unlock_write(mapping
);
3491 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3492 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3493 * cannot race with other handlers or page migration.
3494 * Keep the pte_same checks anyway to make transition from the mutex easier.
3496 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3497 unsigned long address
, pte_t
*ptep
,
3498 struct page
*pagecache_page
, spinlock_t
*ptl
)
3501 struct hstate
*h
= hstate_vma(vma
);
3502 struct page
*old_page
, *new_page
;
3503 int ret
= 0, outside_reserve
= 0;
3504 unsigned long mmun_start
; /* For mmu_notifiers */
3505 unsigned long mmun_end
; /* For mmu_notifiers */
3507 pte
= huge_ptep_get(ptep
);
3508 old_page
= pte_page(pte
);
3511 /* If no-one else is actually using this page, avoid the copy
3512 * and just make the page writable */
3513 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3514 page_move_anon_rmap(old_page
, vma
);
3515 set_huge_ptep_writable(vma
, address
, ptep
);
3520 * If the process that created a MAP_PRIVATE mapping is about to
3521 * perform a COW due to a shared page count, attempt to satisfy
3522 * the allocation without using the existing reserves. The pagecache
3523 * page is used to determine if the reserve at this address was
3524 * consumed or not. If reserves were used, a partial faulted mapping
3525 * at the time of fork() could consume its reserves on COW instead
3526 * of the full address range.
3528 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3529 old_page
!= pagecache_page
)
3530 outside_reserve
= 1;
3535 * Drop page table lock as buddy allocator may be called. It will
3536 * be acquired again before returning to the caller, as expected.
3539 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
3541 if (IS_ERR(new_page
)) {
3543 * If a process owning a MAP_PRIVATE mapping fails to COW,
3544 * it is due to references held by a child and an insufficient
3545 * huge page pool. To guarantee the original mappers
3546 * reliability, unmap the page from child processes. The child
3547 * may get SIGKILLed if it later faults.
3549 if (outside_reserve
) {
3551 BUG_ON(huge_pte_none(pte
));
3552 unmap_ref_private(mm
, vma
, old_page
, address
);
3553 BUG_ON(huge_pte_none(pte
));
3555 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
),
3558 pte_same(huge_ptep_get(ptep
), pte
)))
3559 goto retry_avoidcopy
;
3561 * race occurs while re-acquiring page table
3562 * lock, and our job is done.
3567 ret
= (PTR_ERR(new_page
) == -ENOMEM
) ?
3568 VM_FAULT_OOM
: VM_FAULT_SIGBUS
;
3569 goto out_release_old
;
3573 * When the original hugepage is shared one, it does not have
3574 * anon_vma prepared.
3576 if (unlikely(anon_vma_prepare(vma
))) {
3578 goto out_release_all
;
3581 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3582 pages_per_huge_page(h
));
3583 __SetPageUptodate(new_page
);
3584 set_page_huge_active(new_page
);
3586 mmun_start
= address
& huge_page_mask(h
);
3587 mmun_end
= mmun_start
+ huge_page_size(h
);
3588 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3591 * Retake the page table lock to check for racing updates
3592 * before the page tables are altered
3595 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
),
3597 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3598 ClearPagePrivate(new_page
);
3601 huge_ptep_clear_flush(vma
, address
, ptep
);
3602 mmu_notifier_invalidate_range(mm
, mmun_start
, mmun_end
);
3603 set_huge_pte_at(mm
, address
, ptep
,
3604 make_huge_pte(vma
, new_page
, 1));
3605 page_remove_rmap(old_page
, true);
3606 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
3607 /* Make the old page be freed below */
3608 new_page
= old_page
;
3611 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3613 restore_reserve_on_error(h
, vma
, address
, new_page
);
3618 spin_lock(ptl
); /* Caller expects lock to be held */
3622 /* Return the pagecache page at a given address within a VMA */
3623 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3624 struct vm_area_struct
*vma
, unsigned long address
)
3626 struct address_space
*mapping
;
3629 mapping
= vma
->vm_file
->f_mapping
;
3630 idx
= vma_hugecache_offset(h
, vma
, address
);
3632 return find_lock_page(mapping
, idx
);
3636 * Return whether there is a pagecache page to back given address within VMA.
3637 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3639 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3640 struct vm_area_struct
*vma
, unsigned long address
)
3642 struct address_space
*mapping
;
3646 mapping
= vma
->vm_file
->f_mapping
;
3647 idx
= vma_hugecache_offset(h
, vma
, address
);
3649 page
= find_get_page(mapping
, idx
);
3652 return page
!= NULL
;
3655 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3658 struct inode
*inode
= mapping
->host
;
3659 struct hstate
*h
= hstate_inode(inode
);
3660 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3664 ClearPagePrivate(page
);
3666 spin_lock(&inode
->i_lock
);
3667 inode
->i_blocks
+= blocks_per_huge_page(h
);
3668 spin_unlock(&inode
->i_lock
);
3672 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3673 struct address_space
*mapping
, pgoff_t idx
,
3674 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3676 struct hstate
*h
= hstate_vma(vma
);
3677 int ret
= VM_FAULT_SIGBUS
;
3685 * Currently, we are forced to kill the process in the event the
3686 * original mapper has unmapped pages from the child due to a failed
3687 * COW. Warn that such a situation has occurred as it may not be obvious
3689 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3690 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3696 * Use page lock to guard against racing truncation
3697 * before we get page_table_lock.
3700 page
= find_lock_page(mapping
, idx
);
3702 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3707 * Check for page in userfault range
3709 if (userfaultfd_missing(vma
)) {
3711 struct vm_fault vmf
= {
3716 * Hard to debug if it ends up being
3717 * used by a callee that assumes
3718 * something about the other
3719 * uninitialized fields... same as in
3725 * hugetlb_fault_mutex must be dropped before
3726 * handling userfault. Reacquire after handling
3727 * fault to make calling code simpler.
3729 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
,
3731 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3732 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
3733 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3737 page
= alloc_huge_page(vma
, address
, 0);
3739 ret
= PTR_ERR(page
);
3743 ret
= VM_FAULT_SIGBUS
;
3746 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3747 __SetPageUptodate(page
);
3748 set_page_huge_active(page
);
3750 if (vma
->vm_flags
& VM_MAYSHARE
) {
3751 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3760 if (unlikely(anon_vma_prepare(vma
))) {
3762 goto backout_unlocked
;
3768 * If memory error occurs between mmap() and fault, some process
3769 * don't have hwpoisoned swap entry for errored virtual address.
3770 * So we need to block hugepage fault by PG_hwpoison bit check.
3772 if (unlikely(PageHWPoison(page
))) {
3773 ret
= VM_FAULT_HWPOISON
|
3774 VM_FAULT_SET_HINDEX(hstate_index(h
));
3775 goto backout_unlocked
;
3780 * If we are going to COW a private mapping later, we examine the
3781 * pending reservations for this page now. This will ensure that
3782 * any allocations necessary to record that reservation occur outside
3785 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3786 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3788 goto backout_unlocked
;
3790 /* Just decrements count, does not deallocate */
3791 vma_end_reservation(h
, vma
, address
);
3794 ptl
= huge_pte_lock(h
, mm
, ptep
);
3795 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3800 if (!huge_pte_none(huge_ptep_get(ptep
)))
3804 ClearPagePrivate(page
);
3805 hugepage_add_new_anon_rmap(page
, vma
, address
);
3807 page_dup_rmap(page
, true);
3808 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
3809 && (vma
->vm_flags
& VM_SHARED
)));
3810 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
3812 hugetlb_count_add(pages_per_huge_page(h
), mm
);
3813 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3814 /* Optimization, do the COW without a second fault */
3815 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
3827 restore_reserve_on_error(h
, vma
, address
, page
);
3833 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3834 struct vm_area_struct
*vma
,
3835 struct address_space
*mapping
,
3836 pgoff_t idx
, unsigned long address
)
3838 unsigned long key
[2];
3841 if (vma
->vm_flags
& VM_SHARED
) {
3842 key
[0] = (unsigned long) mapping
;
3845 key
[0] = (unsigned long) mm
;
3846 key
[1] = address
>> huge_page_shift(h
);
3849 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
3851 return hash
& (num_fault_mutexes
- 1);
3855 * For uniprocesor systems we always use a single mutex, so just
3856 * return 0 and avoid the hashing overhead.
3858 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3859 struct vm_area_struct
*vma
,
3860 struct address_space
*mapping
,
3861 pgoff_t idx
, unsigned long address
)
3867 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3868 unsigned long address
, unsigned int flags
)
3875 struct page
*page
= NULL
;
3876 struct page
*pagecache_page
= NULL
;
3877 struct hstate
*h
= hstate_vma(vma
);
3878 struct address_space
*mapping
;
3879 int need_wait_lock
= 0;
3881 address
&= huge_page_mask(h
);
3883 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
3885 entry
= huge_ptep_get(ptep
);
3886 if (unlikely(is_hugetlb_entry_migration(entry
))) {
3887 migration_entry_wait_huge(vma
, mm
, ptep
);
3889 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
3890 return VM_FAULT_HWPOISON_LARGE
|
3891 VM_FAULT_SET_HINDEX(hstate_index(h
));
3893 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
3895 return VM_FAULT_OOM
;
3898 mapping
= vma
->vm_file
->f_mapping
;
3899 idx
= vma_hugecache_offset(h
, vma
, address
);
3902 * Serialize hugepage allocation and instantiation, so that we don't
3903 * get spurious allocation failures if two CPUs race to instantiate
3904 * the same page in the page cache.
3906 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
3907 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3909 entry
= huge_ptep_get(ptep
);
3910 if (huge_pte_none(entry
)) {
3911 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3918 * entry could be a migration/hwpoison entry at this point, so this
3919 * check prevents the kernel from going below assuming that we have
3920 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3921 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3924 if (!pte_present(entry
))
3928 * If we are going to COW the mapping later, we examine the pending
3929 * reservations for this page now. This will ensure that any
3930 * allocations necessary to record that reservation occur outside the
3931 * spinlock. For private mappings, we also lookup the pagecache
3932 * page now as it is used to determine if a reservation has been
3935 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3936 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3940 /* Just decrements count, does not deallocate */
3941 vma_end_reservation(h
, vma
, address
);
3943 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3944 pagecache_page
= hugetlbfs_pagecache_page(h
,
3948 ptl
= huge_pte_lock(h
, mm
, ptep
);
3950 /* Check for a racing update before calling hugetlb_cow */
3951 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3955 * hugetlb_cow() requires page locks of pte_page(entry) and
3956 * pagecache_page, so here we need take the former one
3957 * when page != pagecache_page or !pagecache_page.
3959 page
= pte_page(entry
);
3960 if (page
!= pagecache_page
)
3961 if (!trylock_page(page
)) {
3968 if (flags
& FAULT_FLAG_WRITE
) {
3969 if (!huge_pte_write(entry
)) {
3970 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
3971 pagecache_page
, ptl
);
3974 entry
= huge_pte_mkdirty(entry
);
3976 entry
= pte_mkyoung(entry
);
3977 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3978 flags
& FAULT_FLAG_WRITE
))
3979 update_mmu_cache(vma
, address
, ptep
);
3981 if (page
!= pagecache_page
)
3987 if (pagecache_page
) {
3988 unlock_page(pagecache_page
);
3989 put_page(pagecache_page
);
3992 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3994 * Generally it's safe to hold refcount during waiting page lock. But
3995 * here we just wait to defer the next page fault to avoid busy loop and
3996 * the page is not used after unlocked before returning from the current
3997 * page fault. So we are safe from accessing freed page, even if we wait
3998 * here without taking refcount.
4001 wait_on_page_locked(page
);
4006 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4007 * modifications for huge pages.
4009 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4011 struct vm_area_struct
*dst_vma
,
4012 unsigned long dst_addr
,
4013 unsigned long src_addr
,
4014 struct page
**pagep
)
4016 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4017 struct hstate
*h
= hstate_vma(dst_vma
);
4025 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4029 ret
= copy_huge_page_from_user(page
,
4030 (const void __user
*) src_addr
,
4031 pages_per_huge_page(h
), false);
4033 /* fallback to copy_from_user outside mmap_sem */
4034 if (unlikely(ret
)) {
4037 /* don't free the page */
4046 * The memory barrier inside __SetPageUptodate makes sure that
4047 * preceding stores to the page contents become visible before
4048 * the set_pte_at() write.
4050 __SetPageUptodate(page
);
4051 set_page_huge_active(page
);
4054 * If shared, add to page cache
4057 struct address_space
*mapping
= dst_vma
->vm_file
->f_mapping
;
4058 pgoff_t idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4060 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4062 goto out_release_nounlock
;
4065 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4069 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4070 goto out_release_unlock
;
4073 page_dup_rmap(page
, true);
4075 ClearPagePrivate(page
);
4076 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4079 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4080 if (dst_vma
->vm_flags
& VM_WRITE
)
4081 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4082 _dst_pte
= pte_mkyoung(_dst_pte
);
4084 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4086 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4087 dst_vma
->vm_flags
& VM_WRITE
);
4088 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4090 /* No need to invalidate - it was non-present before */
4091 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4101 out_release_nounlock
:
4108 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4109 struct page
**pages
, struct vm_area_struct
**vmas
,
4110 unsigned long *position
, unsigned long *nr_pages
,
4111 long i
, unsigned int flags
, int *nonblocking
)
4113 unsigned long pfn_offset
;
4114 unsigned long vaddr
= *position
;
4115 unsigned long remainder
= *nr_pages
;
4116 struct hstate
*h
= hstate_vma(vma
);
4118 while (vaddr
< vma
->vm_end
&& remainder
) {
4120 spinlock_t
*ptl
= NULL
;
4125 * If we have a pending SIGKILL, don't keep faulting pages and
4126 * potentially allocating memory.
4128 if (unlikely(fatal_signal_pending(current
))) {
4134 * Some archs (sparc64, sh*) have multiple pte_ts to
4135 * each hugepage. We have to make sure we get the
4136 * first, for the page indexing below to work.
4138 * Note that page table lock is not held when pte is null.
4140 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4143 ptl
= huge_pte_lock(h
, mm
, pte
);
4144 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4147 * When coredumping, it suits get_dump_page if we just return
4148 * an error where there's an empty slot with no huge pagecache
4149 * to back it. This way, we avoid allocating a hugepage, and
4150 * the sparse dumpfile avoids allocating disk blocks, but its
4151 * huge holes still show up with zeroes where they need to be.
4153 if (absent
&& (flags
& FOLL_DUMP
) &&
4154 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4162 * We need call hugetlb_fault for both hugepages under migration
4163 * (in which case hugetlb_fault waits for the migration,) and
4164 * hwpoisoned hugepages (in which case we need to prevent the
4165 * caller from accessing to them.) In order to do this, we use
4166 * here is_swap_pte instead of is_hugetlb_entry_migration and
4167 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4168 * both cases, and because we can't follow correct pages
4169 * directly from any kind of swap entries.
4171 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4172 ((flags
& FOLL_WRITE
) &&
4173 !huge_pte_write(huge_ptep_get(pte
)))) {
4175 unsigned int fault_flags
= 0;
4179 if (flags
& FOLL_WRITE
)
4180 fault_flags
|= FAULT_FLAG_WRITE
;
4182 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
4183 if (flags
& FOLL_NOWAIT
)
4184 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4185 FAULT_FLAG_RETRY_NOWAIT
;
4186 if (flags
& FOLL_TRIED
) {
4187 VM_WARN_ON_ONCE(fault_flags
&
4188 FAULT_FLAG_ALLOW_RETRY
);
4189 fault_flags
|= FAULT_FLAG_TRIED
;
4191 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4192 if (ret
& VM_FAULT_ERROR
) {
4193 int err
= vm_fault_to_errno(ret
, flags
);
4201 if (ret
& VM_FAULT_RETRY
) {
4206 * VM_FAULT_RETRY must not return an
4207 * error, it will return zero
4210 * No need to update "position" as the
4211 * caller will not check it after
4212 * *nr_pages is set to 0.
4219 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4220 page
= pte_page(huge_ptep_get(pte
));
4223 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4234 if (vaddr
< vma
->vm_end
&& remainder
&&
4235 pfn_offset
< pages_per_huge_page(h
)) {
4237 * We use pfn_offset to avoid touching the pageframes
4238 * of this compound page.
4244 *nr_pages
= remainder
;
4246 * setting position is actually required only if remainder is
4247 * not zero but it's faster not to add a "if (remainder)"
4252 return i
? i
: -EFAULT
;
4255 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4257 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4260 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4263 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4264 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4266 struct mm_struct
*mm
= vma
->vm_mm
;
4267 unsigned long start
= address
;
4270 struct hstate
*h
= hstate_vma(vma
);
4271 unsigned long pages
= 0;
4273 BUG_ON(address
>= end
);
4274 flush_cache_range(vma
, address
, end
);
4276 mmu_notifier_invalidate_range_start(mm
, start
, end
);
4277 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4278 for (; address
< end
; address
+= huge_page_size(h
)) {
4280 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4283 ptl
= huge_pte_lock(h
, mm
, ptep
);
4284 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4289 pte
= huge_ptep_get(ptep
);
4290 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4294 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4295 swp_entry_t entry
= pte_to_swp_entry(pte
);
4297 if (is_write_migration_entry(entry
)) {
4300 make_migration_entry_read(&entry
);
4301 newpte
= swp_entry_to_pte(entry
);
4302 set_huge_swap_pte_at(mm
, address
, ptep
,
4303 newpte
, huge_page_size(h
));
4309 if (!huge_pte_none(pte
)) {
4310 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
4311 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
4312 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4313 set_huge_pte_at(mm
, address
, ptep
, pte
);
4319 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4320 * may have cleared our pud entry and done put_page on the page table:
4321 * once we release i_mmap_rwsem, another task can do the final put_page
4322 * and that page table be reused and filled with junk.
4324 flush_hugetlb_tlb_range(vma
, start
, end
);
4325 mmu_notifier_invalidate_range(mm
, start
, end
);
4326 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4327 mmu_notifier_invalidate_range_end(mm
, start
, end
);
4329 return pages
<< h
->order
;
4332 int hugetlb_reserve_pages(struct inode
*inode
,
4334 struct vm_area_struct
*vma
,
4335 vm_flags_t vm_flags
)
4338 struct hstate
*h
= hstate_inode(inode
);
4339 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4340 struct resv_map
*resv_map
;
4344 * Only apply hugepage reservation if asked. At fault time, an
4345 * attempt will be made for VM_NORESERVE to allocate a page
4346 * without using reserves
4348 if (vm_flags
& VM_NORESERVE
)
4352 * Shared mappings base their reservation on the number of pages that
4353 * are already allocated on behalf of the file. Private mappings need
4354 * to reserve the full area even if read-only as mprotect() may be
4355 * called to make the mapping read-write. Assume !vma is a shm mapping
4357 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4358 resv_map
= inode_resv_map(inode
);
4360 chg
= region_chg(resv_map
, from
, to
);
4363 resv_map
= resv_map_alloc();
4369 set_vma_resv_map(vma
, resv_map
);
4370 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4379 * There must be enough pages in the subpool for the mapping. If
4380 * the subpool has a minimum size, there may be some global
4381 * reservations already in place (gbl_reserve).
4383 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4384 if (gbl_reserve
< 0) {
4390 * Check enough hugepages are available for the reservation.
4391 * Hand the pages back to the subpool if there are not
4393 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4395 /* put back original number of pages, chg */
4396 (void)hugepage_subpool_put_pages(spool
, chg
);
4401 * Account for the reservations made. Shared mappings record regions
4402 * that have reservations as they are shared by multiple VMAs.
4403 * When the last VMA disappears, the region map says how much
4404 * the reservation was and the page cache tells how much of
4405 * the reservation was consumed. Private mappings are per-VMA and
4406 * only the consumed reservations are tracked. When the VMA
4407 * disappears, the original reservation is the VMA size and the
4408 * consumed reservations are stored in the map. Hence, nothing
4409 * else has to be done for private mappings here
4411 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4412 long add
= region_add(resv_map
, from
, to
);
4414 if (unlikely(chg
> add
)) {
4416 * pages in this range were added to the reserve
4417 * map between region_chg and region_add. This
4418 * indicates a race with alloc_huge_page. Adjust
4419 * the subpool and reserve counts modified above
4420 * based on the difference.
4424 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4426 hugetlb_acct_memory(h
, -rsv_adjust
);
4431 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4432 /* Don't call region_abort if region_chg failed */
4434 region_abort(resv_map
, from
, to
);
4435 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4436 kref_put(&resv_map
->refs
, resv_map_release
);
4440 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4443 struct hstate
*h
= hstate_inode(inode
);
4444 struct resv_map
*resv_map
= inode_resv_map(inode
);
4446 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4450 chg
= region_del(resv_map
, start
, end
);
4452 * region_del() can fail in the rare case where a region
4453 * must be split and another region descriptor can not be
4454 * allocated. If end == LONG_MAX, it will not fail.
4460 spin_lock(&inode
->i_lock
);
4461 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4462 spin_unlock(&inode
->i_lock
);
4465 * If the subpool has a minimum size, the number of global
4466 * reservations to be released may be adjusted.
4468 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4469 hugetlb_acct_memory(h
, -gbl_reserve
);
4474 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4475 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4476 struct vm_area_struct
*vma
,
4477 unsigned long addr
, pgoff_t idx
)
4479 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4481 unsigned long sbase
= saddr
& PUD_MASK
;
4482 unsigned long s_end
= sbase
+ PUD_SIZE
;
4484 /* Allow segments to share if only one is marked locked */
4485 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4486 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4489 * match the virtual addresses, permission and the alignment of the
4492 if (pmd_index(addr
) != pmd_index(saddr
) ||
4493 vm_flags
!= svm_flags
||
4494 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4500 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4502 unsigned long base
= addr
& PUD_MASK
;
4503 unsigned long end
= base
+ PUD_SIZE
;
4506 * check on proper vm_flags and page table alignment
4508 if (vma
->vm_flags
& VM_MAYSHARE
&&
4509 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
4515 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4516 * and returns the corresponding pte. While this is not necessary for the
4517 * !shared pmd case because we can allocate the pmd later as well, it makes the
4518 * code much cleaner. pmd allocation is essential for the shared case because
4519 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4520 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4521 * bad pmd for sharing.
4523 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4525 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4526 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4527 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4529 struct vm_area_struct
*svma
;
4530 unsigned long saddr
;
4535 if (!vma_shareable(vma
, addr
))
4536 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4538 i_mmap_lock_write(mapping
);
4539 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4543 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4545 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
4546 vma_mmu_pagesize(svma
));
4548 get_page(virt_to_page(spte
));
4557 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
4558 if (pud_none(*pud
)) {
4559 pud_populate(mm
, pud
,
4560 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4563 put_page(virt_to_page(spte
));
4567 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4568 i_mmap_unlock_write(mapping
);
4573 * unmap huge page backed by shared pte.
4575 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4576 * indicated by page_count > 1, unmap is achieved by clearing pud and
4577 * decrementing the ref count. If count == 1, the pte page is not shared.
4579 * called with page table lock held.
4581 * returns: 1 successfully unmapped a shared pte page
4582 * 0 the underlying pte page is not shared, or it is the last user
4584 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4586 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4587 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
4588 pud_t
*pud
= pud_offset(p4d
, *addr
);
4590 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4591 if (page_count(virt_to_page(ptep
)) == 1)
4595 put_page(virt_to_page(ptep
));
4597 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4600 #define want_pmd_share() (1)
4601 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4602 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4607 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4611 #define want_pmd_share() (0)
4612 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4614 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4615 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4616 unsigned long addr
, unsigned long sz
)
4623 pgd
= pgd_offset(mm
, addr
);
4624 p4d
= p4d_offset(pgd
, addr
);
4625 pud
= pud_alloc(mm
, p4d
, addr
);
4627 if (sz
== PUD_SIZE
) {
4630 BUG_ON(sz
!= PMD_SIZE
);
4631 if (want_pmd_share() && pud_none(*pud
))
4632 pte
= huge_pmd_share(mm
, addr
, pud
);
4634 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4637 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
4642 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
4643 unsigned long addr
, unsigned long sz
)
4650 pgd
= pgd_offset(mm
, addr
);
4651 if (!pgd_present(*pgd
))
4653 p4d
= p4d_offset(pgd
, addr
);
4654 if (!p4d_present(*p4d
))
4656 pud
= pud_offset(p4d
, addr
);
4657 if (!pud_present(*pud
))
4660 return (pte_t
*)pud
;
4661 pmd
= pmd_offset(pud
, addr
);
4662 return (pte_t
*) pmd
;
4665 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4668 * These functions are overwritable if your architecture needs its own
4671 struct page
* __weak
4672 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
4675 return ERR_PTR(-EINVAL
);
4678 struct page
* __weak
4679 follow_huge_pd(struct vm_area_struct
*vma
,
4680 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
4682 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
4686 struct page
* __weak
4687 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
4688 pmd_t
*pmd
, int flags
)
4690 struct page
*page
= NULL
;
4694 ptl
= pmd_lockptr(mm
, pmd
);
4697 * make sure that the address range covered by this pmd is not
4698 * unmapped from other threads.
4700 if (!pmd_huge(*pmd
))
4702 pte
= huge_ptep_get((pte_t
*)pmd
);
4703 if (pte_present(pte
)) {
4704 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
4705 if (flags
& FOLL_GET
)
4708 if (is_hugetlb_entry_migration(pte
)) {
4710 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
4714 * hwpoisoned entry is treated as no_page_table in
4715 * follow_page_mask().
4723 struct page
* __weak
4724 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
4725 pud_t
*pud
, int flags
)
4727 if (flags
& FOLL_GET
)
4730 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
4733 struct page
* __weak
4734 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
4736 if (flags
& FOLL_GET
)
4739 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
4742 #ifdef CONFIG_MEMORY_FAILURE
4745 * This function is called from memory failure code.
4747 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
4749 struct hstate
*h
= page_hstate(hpage
);
4750 int nid
= page_to_nid(hpage
);
4753 spin_lock(&hugetlb_lock
);
4755 * Just checking !page_huge_active is not enough, because that could be
4756 * an isolated/hwpoisoned hugepage (which have >0 refcount).
4758 if (!page_huge_active(hpage
) && !page_count(hpage
)) {
4760 * Hwpoisoned hugepage isn't linked to activelist or freelist,
4761 * but dangling hpage->lru can trigger list-debug warnings
4762 * (this happens when we call unpoison_memory() on it),
4763 * so let it point to itself with list_del_init().
4765 list_del_init(&hpage
->lru
);
4766 set_page_refcounted(hpage
);
4767 h
->free_huge_pages
--;
4768 h
->free_huge_pages_node
[nid
]--;
4771 spin_unlock(&hugetlb_lock
);
4776 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
4780 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4781 spin_lock(&hugetlb_lock
);
4782 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
4786 clear_page_huge_active(page
);
4787 list_move_tail(&page
->lru
, list
);
4789 spin_unlock(&hugetlb_lock
);
4793 void putback_active_hugepage(struct page
*page
)
4795 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4796 spin_lock(&hugetlb_lock
);
4797 set_page_huge_active(page
);
4798 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
4799 spin_unlock(&hugetlb_lock
);