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/mmdebug.h>
22 #include <linux/sched/signal.h>
23 #include <linux/rmap.h>
24 #include <linux/string_helpers.h>
25 #include <linux/swap.h>
26 #include <linux/swapops.h>
27 #include <linux/jhash.h>
30 #include <asm/pgtable.h>
34 #include <linux/hugetlb.h>
35 #include <linux/hugetlb_cgroup.h>
36 #include <linux/node.h>
37 #include <linux/userfaultfd_k.h>
40 int hugepages_treat_as_movable
;
42 int hugetlb_max_hstate __read_mostly
;
43 unsigned int default_hstate_idx
;
44 struct hstate hstates
[HUGE_MAX_HSTATE
];
46 * Minimum page order among possible hugepage sizes, set to a proper value
49 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
51 __initdata
LIST_HEAD(huge_boot_pages
);
53 /* for command line parsing */
54 static struct hstate
* __initdata parsed_hstate
;
55 static unsigned long __initdata default_hstate_max_huge_pages
;
56 static unsigned long __initdata default_hstate_size
;
57 static bool __initdata parsed_valid_hugepagesz
= true;
60 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
61 * free_huge_pages, and surplus_huge_pages.
63 DEFINE_SPINLOCK(hugetlb_lock
);
66 * Serializes faults on the same logical page. This is used to
67 * prevent spurious OOMs when the hugepage pool is fully utilized.
69 static int num_fault_mutexes
;
70 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
72 /* Forward declaration */
73 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
75 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
77 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
79 spin_unlock(&spool
->lock
);
81 /* If no pages are used, and no other handles to the subpool
82 * remain, give up any reservations mased on minimum size and
85 if (spool
->min_hpages
!= -1)
86 hugetlb_acct_memory(spool
->hstate
,
92 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
95 struct hugepage_subpool
*spool
;
97 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
101 spin_lock_init(&spool
->lock
);
103 spool
->max_hpages
= max_hpages
;
105 spool
->min_hpages
= min_hpages
;
107 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
111 spool
->rsv_hpages
= min_hpages
;
116 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
118 spin_lock(&spool
->lock
);
119 BUG_ON(!spool
->count
);
121 unlock_or_release_subpool(spool
);
125 * Subpool accounting for allocating and reserving pages.
126 * Return -ENOMEM if there are not enough resources to satisfy the
127 * the request. Otherwise, return the number of pages by which the
128 * global pools must be adjusted (upward). The returned value may
129 * only be different than the passed value (delta) in the case where
130 * a subpool minimum size must be manitained.
132 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
140 spin_lock(&spool
->lock
);
142 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
143 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
144 spool
->used_hpages
+= delta
;
151 /* minimum size accounting */
152 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
153 if (delta
> spool
->rsv_hpages
) {
155 * Asking for more reserves than those already taken on
156 * behalf of subpool. Return difference.
158 ret
= delta
- spool
->rsv_hpages
;
159 spool
->rsv_hpages
= 0;
161 ret
= 0; /* reserves already accounted for */
162 spool
->rsv_hpages
-= delta
;
167 spin_unlock(&spool
->lock
);
172 * Subpool accounting for freeing and unreserving pages.
173 * Return the number of global page reservations that must be dropped.
174 * The return value may only be different than the passed value (delta)
175 * in the case where a subpool minimum size must be maintained.
177 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
185 spin_lock(&spool
->lock
);
187 if (spool
->max_hpages
!= -1) /* maximum size accounting */
188 spool
->used_hpages
-= delta
;
190 /* minimum size accounting */
191 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
192 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
195 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
197 spool
->rsv_hpages
+= delta
;
198 if (spool
->rsv_hpages
> spool
->min_hpages
)
199 spool
->rsv_hpages
= spool
->min_hpages
;
203 * If hugetlbfs_put_super couldn't free spool due to an outstanding
204 * quota reference, free it now.
206 unlock_or_release_subpool(spool
);
211 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
213 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
216 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
218 return subpool_inode(file_inode(vma
->vm_file
));
222 * Region tracking -- allows tracking of reservations and instantiated pages
223 * across the pages in a mapping.
225 * The region data structures are embedded into a resv_map and protected
226 * by a resv_map's lock. The set of regions within the resv_map represent
227 * reservations for huge pages, or huge pages that have already been
228 * instantiated within the map. The from and to elements are huge page
229 * indicies into the associated mapping. from indicates the starting index
230 * of the region. to represents the first index past the end of the region.
232 * For example, a file region structure with from == 0 and to == 4 represents
233 * four huge pages in a mapping. It is important to note that the to element
234 * represents the first element past the end of the region. This is used in
235 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
237 * Interval notation of the form [from, to) will be used to indicate that
238 * the endpoint from is inclusive and to is exclusive.
241 struct list_head link
;
247 * Add the huge page range represented by [f, t) to the reserve
248 * map. In the normal case, existing regions will be expanded
249 * to accommodate the specified range. Sufficient regions should
250 * exist for expansion due to the previous call to region_chg
251 * with the same range. However, it is possible that region_del
252 * could have been called after region_chg and modifed the map
253 * in such a way that no region exists to be expanded. In this
254 * case, pull a region descriptor from the cache associated with
255 * the map and use that for the new range.
257 * Return the number of new huge pages added to the map. This
258 * number is greater than or equal to zero.
260 static long region_add(struct resv_map
*resv
, long f
, long t
)
262 struct list_head
*head
= &resv
->regions
;
263 struct file_region
*rg
, *nrg
, *trg
;
266 spin_lock(&resv
->lock
);
267 /* Locate the region we are either in or before. */
268 list_for_each_entry(rg
, head
, link
)
273 * If no region exists which can be expanded to include the
274 * specified range, the list must have been modified by an
275 * interleving call to region_del(). Pull a region descriptor
276 * from the cache and use it for this range.
278 if (&rg
->link
== head
|| t
< rg
->from
) {
279 VM_BUG_ON(resv
->region_cache_count
<= 0);
281 resv
->region_cache_count
--;
282 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
284 list_del(&nrg
->link
);
288 list_add(&nrg
->link
, rg
->link
.prev
);
294 /* Round our left edge to the current segment if it encloses us. */
298 /* Check for and consume any regions we now overlap with. */
300 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
301 if (&rg
->link
== head
)
306 /* If this area reaches higher then extend our area to
307 * include it completely. If this is not the first area
308 * which we intend to reuse, free it. */
312 /* Decrement return value by the deleted range.
313 * Another range will span this area so that by
314 * end of routine add will be >= zero
316 add
-= (rg
->to
- rg
->from
);
322 add
+= (nrg
->from
- f
); /* Added to beginning of region */
324 add
+= t
- nrg
->to
; /* Added to end of region */
328 resv
->adds_in_progress
--;
329 spin_unlock(&resv
->lock
);
335 * Examine the existing reserve map and determine how many
336 * huge pages in the specified range [f, t) are NOT currently
337 * represented. This routine is called before a subsequent
338 * call to region_add that will actually modify the reserve
339 * map to add the specified range [f, t). region_chg does
340 * not change the number of huge pages represented by the
341 * map. However, if the existing regions in the map can not
342 * be expanded to represent the new range, a new file_region
343 * structure is added to the map as a placeholder. This is
344 * so that the subsequent region_add call will have all the
345 * regions it needs and will not fail.
347 * Upon entry, region_chg will also examine the cache of region descriptors
348 * associated with the map. If there are not enough descriptors cached, one
349 * will be allocated for the in progress add operation.
351 * Returns the number of huge pages that need to be added to the existing
352 * reservation map for the range [f, t). This number is greater or equal to
353 * zero. -ENOMEM is returned if a new file_region structure or cache entry
354 * is needed and can not be allocated.
356 static long region_chg(struct resv_map
*resv
, long f
, long t
)
358 struct list_head
*head
= &resv
->regions
;
359 struct file_region
*rg
, *nrg
= NULL
;
363 spin_lock(&resv
->lock
);
365 resv
->adds_in_progress
++;
368 * Check for sufficient descriptors in the cache to accommodate
369 * the number of in progress add operations.
371 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
372 struct file_region
*trg
;
374 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
375 /* Must drop lock to allocate a new descriptor. */
376 resv
->adds_in_progress
--;
377 spin_unlock(&resv
->lock
);
379 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
385 spin_lock(&resv
->lock
);
386 list_add(&trg
->link
, &resv
->region_cache
);
387 resv
->region_cache_count
++;
391 /* Locate the region we are before or in. */
392 list_for_each_entry(rg
, head
, link
)
396 /* If we are below the current region then a new region is required.
397 * Subtle, allocate a new region at the position but make it zero
398 * size such that we can guarantee to record the reservation. */
399 if (&rg
->link
== head
|| t
< rg
->from
) {
401 resv
->adds_in_progress
--;
402 spin_unlock(&resv
->lock
);
403 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
409 INIT_LIST_HEAD(&nrg
->link
);
413 list_add(&nrg
->link
, rg
->link
.prev
);
418 /* Round our left edge to the current segment if it encloses us. */
423 /* Check for and consume any regions we now overlap with. */
424 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
425 if (&rg
->link
== head
)
430 /* We overlap with this area, if it extends further than
431 * us then we must extend ourselves. Account for its
432 * existing reservation. */
437 chg
-= rg
->to
- rg
->from
;
441 spin_unlock(&resv
->lock
);
442 /* We already know we raced and no longer need the new region */
446 spin_unlock(&resv
->lock
);
451 * Abort the in progress add operation. The adds_in_progress field
452 * of the resv_map keeps track of the operations in progress between
453 * calls to region_chg and region_add. Operations are sometimes
454 * aborted after the call to region_chg. In such cases, region_abort
455 * is called to decrement the adds_in_progress counter.
457 * NOTE: The range arguments [f, t) are not needed or used in this
458 * routine. They are kept to make reading the calling code easier as
459 * arguments will match the associated region_chg call.
461 static void region_abort(struct resv_map
*resv
, long f
, long t
)
463 spin_lock(&resv
->lock
);
464 VM_BUG_ON(!resv
->region_cache_count
);
465 resv
->adds_in_progress
--;
466 spin_unlock(&resv
->lock
);
470 * Delete the specified range [f, t) from the reserve map. If the
471 * t parameter is LONG_MAX, this indicates that ALL regions after f
472 * should be deleted. Locate the regions which intersect [f, t)
473 * and either trim, delete or split the existing regions.
475 * Returns the number of huge pages deleted from the reserve map.
476 * In the normal case, the return value is zero or more. In the
477 * case where a region must be split, a new region descriptor must
478 * be allocated. If the allocation fails, -ENOMEM will be returned.
479 * NOTE: If the parameter t == LONG_MAX, then we will never split
480 * a region and possibly return -ENOMEM. Callers specifying
481 * t == LONG_MAX do not need to check for -ENOMEM error.
483 static long region_del(struct resv_map
*resv
, long f
, long t
)
485 struct list_head
*head
= &resv
->regions
;
486 struct file_region
*rg
, *trg
;
487 struct file_region
*nrg
= NULL
;
491 spin_lock(&resv
->lock
);
492 list_for_each_entry_safe(rg
, trg
, head
, link
) {
494 * Skip regions before the range to be deleted. file_region
495 * ranges are normally of the form [from, to). However, there
496 * may be a "placeholder" entry in the map which is of the form
497 * (from, to) with from == to. Check for placeholder entries
498 * at the beginning of the range to be deleted.
500 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
506 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
508 * Check for an entry in the cache before dropping
509 * lock and attempting allocation.
512 resv
->region_cache_count
> resv
->adds_in_progress
) {
513 nrg
= list_first_entry(&resv
->region_cache
,
516 list_del(&nrg
->link
);
517 resv
->region_cache_count
--;
521 spin_unlock(&resv
->lock
);
522 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
530 /* New entry for end of split region */
533 INIT_LIST_HEAD(&nrg
->link
);
535 /* Original entry is trimmed */
538 list_add(&nrg
->link
, &rg
->link
);
543 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
544 del
+= rg
->to
- rg
->from
;
550 if (f
<= rg
->from
) { /* Trim beginning of region */
553 } else { /* Trim end of region */
559 spin_unlock(&resv
->lock
);
565 * A rare out of memory error was encountered which prevented removal of
566 * the reserve map region for a page. The huge page itself was free'ed
567 * and removed from the page cache. This routine will adjust the subpool
568 * usage count, and the global reserve count if needed. By incrementing
569 * these counts, the reserve map entry which could not be deleted will
570 * appear as a "reserved" entry instead of simply dangling with incorrect
573 void hugetlb_fix_reserve_counts(struct inode
*inode
)
575 struct hugepage_subpool
*spool
= subpool_inode(inode
);
578 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
580 struct hstate
*h
= hstate_inode(inode
);
582 hugetlb_acct_memory(h
, 1);
587 * Count and return the number of huge pages in the reserve map
588 * that intersect with the range [f, t).
590 static long region_count(struct resv_map
*resv
, long f
, long t
)
592 struct list_head
*head
= &resv
->regions
;
593 struct file_region
*rg
;
596 spin_lock(&resv
->lock
);
597 /* Locate each segment we overlap with, and count that overlap. */
598 list_for_each_entry(rg
, head
, link
) {
607 seg_from
= max(rg
->from
, f
);
608 seg_to
= min(rg
->to
, t
);
610 chg
+= seg_to
- seg_from
;
612 spin_unlock(&resv
->lock
);
618 * Convert the address within this vma to the page offset within
619 * the mapping, in pagecache page units; huge pages here.
621 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
622 struct vm_area_struct
*vma
, unsigned long address
)
624 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
625 (vma
->vm_pgoff
>> huge_page_order(h
));
628 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
629 unsigned long address
)
631 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
633 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
636 * Return the size of the pages allocated when backing a VMA. In the majority
637 * cases this will be same size as used by the page table entries.
639 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
641 struct hstate
*hstate
;
643 if (!is_vm_hugetlb_page(vma
))
646 hstate
= hstate_vma(vma
);
648 return 1UL << huge_page_shift(hstate
);
650 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
653 * Return the page size being used by the MMU to back a VMA. In the majority
654 * of cases, the page size used by the kernel matches the MMU size. On
655 * architectures where it differs, an architecture-specific version of this
656 * function is required.
658 #ifndef vma_mmu_pagesize
659 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
661 return vma_kernel_pagesize(vma
);
666 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
667 * bits of the reservation map pointer, which are always clear due to
670 #define HPAGE_RESV_OWNER (1UL << 0)
671 #define HPAGE_RESV_UNMAPPED (1UL << 1)
672 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
675 * These helpers are used to track how many pages are reserved for
676 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
677 * is guaranteed to have their future faults succeed.
679 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
680 * the reserve counters are updated with the hugetlb_lock held. It is safe
681 * to reset the VMA at fork() time as it is not in use yet and there is no
682 * chance of the global counters getting corrupted as a result of the values.
684 * The private mapping reservation is represented in a subtly different
685 * manner to a shared mapping. A shared mapping has a region map associated
686 * with the underlying file, this region map represents the backing file
687 * pages which have ever had a reservation assigned which this persists even
688 * after the page is instantiated. A private mapping has a region map
689 * associated with the original mmap which is attached to all VMAs which
690 * reference it, this region map represents those offsets which have consumed
691 * reservation ie. where pages have been instantiated.
693 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
695 return (unsigned long)vma
->vm_private_data
;
698 static void set_vma_private_data(struct vm_area_struct
*vma
,
701 vma
->vm_private_data
= (void *)value
;
704 struct resv_map
*resv_map_alloc(void)
706 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
707 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
709 if (!resv_map
|| !rg
) {
715 kref_init(&resv_map
->refs
);
716 spin_lock_init(&resv_map
->lock
);
717 INIT_LIST_HEAD(&resv_map
->regions
);
719 resv_map
->adds_in_progress
= 0;
721 INIT_LIST_HEAD(&resv_map
->region_cache
);
722 list_add(&rg
->link
, &resv_map
->region_cache
);
723 resv_map
->region_cache_count
= 1;
728 void resv_map_release(struct kref
*ref
)
730 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
731 struct list_head
*head
= &resv_map
->region_cache
;
732 struct file_region
*rg
, *trg
;
734 /* Clear out any active regions before we release the map. */
735 region_del(resv_map
, 0, LONG_MAX
);
737 /* ... and any entries left in the cache */
738 list_for_each_entry_safe(rg
, trg
, head
, link
) {
743 VM_BUG_ON(resv_map
->adds_in_progress
);
748 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
750 return inode
->i_mapping
->private_data
;
753 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
755 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
756 if (vma
->vm_flags
& VM_MAYSHARE
) {
757 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
758 struct inode
*inode
= mapping
->host
;
760 return inode_resv_map(inode
);
763 return (struct resv_map
*)(get_vma_private_data(vma
) &
768 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
770 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
771 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
773 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
774 HPAGE_RESV_MASK
) | (unsigned long)map
);
777 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
779 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
780 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
782 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
785 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
787 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
789 return (get_vma_private_data(vma
) & flag
) != 0;
792 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
793 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
795 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
796 if (!(vma
->vm_flags
& VM_MAYSHARE
))
797 vma
->vm_private_data
= (void *)0;
800 /* Returns true if the VMA has associated reserve pages */
801 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
803 if (vma
->vm_flags
& VM_NORESERVE
) {
805 * This address is already reserved by other process(chg == 0),
806 * so, we should decrement reserved count. Without decrementing,
807 * reserve count remains after releasing inode, because this
808 * allocated page will go into page cache and is regarded as
809 * coming from reserved pool in releasing step. Currently, we
810 * don't have any other solution to deal with this situation
811 * properly, so add work-around here.
813 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
819 /* Shared mappings always use reserves */
820 if (vma
->vm_flags
& VM_MAYSHARE
) {
822 * We know VM_NORESERVE is not set. Therefore, there SHOULD
823 * be a region map for all pages. The only situation where
824 * there is no region map is if a hole was punched via
825 * fallocate. In this case, there really are no reverves to
826 * use. This situation is indicated if chg != 0.
835 * Only the process that called mmap() has reserves for
838 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
840 * Like the shared case above, a hole punch or truncate
841 * could have been performed on the private mapping.
842 * Examine the value of chg to determine if reserves
843 * actually exist or were previously consumed.
844 * Very Subtle - The value of chg comes from a previous
845 * call to vma_needs_reserves(). The reserve map for
846 * private mappings has different (opposite) semantics
847 * than that of shared mappings. vma_needs_reserves()
848 * has already taken this difference in semantics into
849 * account. Therefore, the meaning of chg is the same
850 * as in the shared case above. Code could easily be
851 * combined, but keeping it separate draws attention to
852 * subtle differences.
863 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
865 int nid
= page_to_nid(page
);
866 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
867 h
->free_huge_pages
++;
868 h
->free_huge_pages_node
[nid
]++;
871 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
875 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
876 if (!PageHWPoison(page
))
879 * if 'non-isolated free hugepage' not found on the list,
880 * the allocation fails.
882 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
884 list_move(&page
->lru
, &h
->hugepage_activelist
);
885 set_page_refcounted(page
);
886 h
->free_huge_pages
--;
887 h
->free_huge_pages_node
[nid
]--;
891 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
894 unsigned int cpuset_mems_cookie
;
895 struct zonelist
*zonelist
;
900 zonelist
= node_zonelist(nid
, gfp_mask
);
903 cpuset_mems_cookie
= read_mems_allowed_begin();
904 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
907 if (!cpuset_zone_allowed(zone
, gfp_mask
))
910 * no need to ask again on the same node. Pool is node rather than
913 if (zone_to_nid(zone
) == node
)
915 node
= zone_to_nid(zone
);
917 page
= dequeue_huge_page_node_exact(h
, node
);
921 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
927 /* Movability of hugepages depends on migration support. */
928 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
930 if (hugepages_treat_as_movable
|| hugepage_migration_supported(h
))
931 return GFP_HIGHUSER_MOVABLE
;
936 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
937 struct vm_area_struct
*vma
,
938 unsigned long address
, int avoid_reserve
,
942 struct mempolicy
*mpol
;
944 nodemask_t
*nodemask
;
948 * A child process with MAP_PRIVATE mappings created by their parent
949 * have no page reserves. This check ensures that reservations are
950 * not "stolen". The child may still get SIGKILLed
952 if (!vma_has_reserves(vma
, chg
) &&
953 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
956 /* If reserves cannot be used, ensure enough pages are in the pool */
957 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
960 gfp_mask
= htlb_alloc_mask(h
);
961 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
962 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
963 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
964 SetPagePrivate(page
);
965 h
->resv_huge_pages
--;
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
, gfp_t gfp_mask
)
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
, struct hstate
*h
)
1114 unsigned int order
= huge_page_order(h
);
1115 unsigned long nr_pages
= 1 << order
;
1116 unsigned long ret
, pfn
, flags
;
1117 struct zonelist
*zonelist
;
1122 gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1123 zonelist
= node_zonelist(nid
, gfp_mask
);
1124 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), NULL
) {
1125 spin_lock_irqsave(&zone
->lock
, flags
);
1127 pfn
= ALIGN(zone
->zone_start_pfn
, nr_pages
);
1128 while (zone_spans_last_pfn(zone
, pfn
, nr_pages
)) {
1129 if (pfn_range_valid_gigantic(zone
, pfn
, nr_pages
)) {
1131 * We release the zone lock here because
1132 * alloc_contig_range() will also lock the zone
1133 * at some point. If there's an allocation
1134 * spinning on this lock, it may win the race
1135 * and cause alloc_contig_range() to fail...
1137 spin_unlock_irqrestore(&zone
->lock
, flags
);
1138 ret
= __alloc_gigantic_page(pfn
, nr_pages
, gfp_mask
);
1140 return pfn_to_page(pfn
);
1141 spin_lock_irqsave(&zone
->lock
, flags
);
1146 spin_unlock_irqrestore(&zone
->lock
, flags
);
1152 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1153 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1155 static struct page
*alloc_fresh_gigantic_page_node(struct hstate
*h
, int nid
)
1159 page
= alloc_gigantic_page(nid
, h
);
1161 prep_compound_gigantic_page(page
, huge_page_order(h
));
1162 prep_new_huge_page(h
, page
, nid
);
1168 static int alloc_fresh_gigantic_page(struct hstate
*h
,
1169 nodemask_t
*nodes_allowed
)
1171 struct page
*page
= NULL
;
1174 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1175 page
= alloc_fresh_gigantic_page_node(h
, node
);
1183 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1184 static inline bool gigantic_page_supported(void) { return false; }
1185 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1186 static inline void destroy_compound_gigantic_page(struct page
*page
,
1187 unsigned int order
) { }
1188 static inline int alloc_fresh_gigantic_page(struct hstate
*h
,
1189 nodemask_t
*nodes_allowed
) { return 0; }
1192 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1196 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
1200 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1201 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1202 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1203 1 << PG_referenced
| 1 << PG_dirty
|
1204 1 << PG_active
| 1 << PG_private
|
1207 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1208 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1209 set_page_refcounted(page
);
1210 if (hstate_is_gigantic(h
)) {
1211 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1212 free_gigantic_page(page
, huge_page_order(h
));
1214 __free_pages(page
, huge_page_order(h
));
1218 struct hstate
*size_to_hstate(unsigned long size
)
1222 for_each_hstate(h
) {
1223 if (huge_page_size(h
) == size
)
1230 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1231 * to hstate->hugepage_activelist.)
1233 * This function can be called for tail pages, but never returns true for them.
1235 bool page_huge_active(struct page
*page
)
1237 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1238 return PageHead(page
) && PagePrivate(&page
[1]);
1241 /* never called for tail page */
1242 static void set_page_huge_active(struct page
*page
)
1244 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1245 SetPagePrivate(&page
[1]);
1248 static void clear_page_huge_active(struct page
*page
)
1250 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1251 ClearPagePrivate(&page
[1]);
1254 void free_huge_page(struct page
*page
)
1257 * Can't pass hstate in here because it is called from the
1258 * compound page destructor.
1260 struct hstate
*h
= page_hstate(page
);
1261 int nid
= page_to_nid(page
);
1262 struct hugepage_subpool
*spool
=
1263 (struct hugepage_subpool
*)page_private(page
);
1264 bool restore_reserve
;
1266 set_page_private(page
, 0);
1267 page
->mapping
= NULL
;
1268 VM_BUG_ON_PAGE(page_count(page
), page
);
1269 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1270 restore_reserve
= PagePrivate(page
);
1271 ClearPagePrivate(page
);
1274 * A return code of zero implies that the subpool will be under its
1275 * minimum size if the reservation is not restored after page is free.
1276 * Therefore, force restore_reserve operation.
1278 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1279 restore_reserve
= true;
1281 spin_lock(&hugetlb_lock
);
1282 clear_page_huge_active(page
);
1283 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1284 pages_per_huge_page(h
), page
);
1285 if (restore_reserve
)
1286 h
->resv_huge_pages
++;
1288 if (h
->surplus_huge_pages_node
[nid
]) {
1289 /* remove the page from active list */
1290 list_del(&page
->lru
);
1291 update_and_free_page(h
, page
);
1292 h
->surplus_huge_pages
--;
1293 h
->surplus_huge_pages_node
[nid
]--;
1295 arch_clear_hugepage_flags(page
);
1296 enqueue_huge_page(h
, page
);
1298 spin_unlock(&hugetlb_lock
);
1301 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1303 INIT_LIST_HEAD(&page
->lru
);
1304 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1305 spin_lock(&hugetlb_lock
);
1306 set_hugetlb_cgroup(page
, NULL
);
1308 h
->nr_huge_pages_node
[nid
]++;
1309 spin_unlock(&hugetlb_lock
);
1310 put_page(page
); /* free it into the hugepage allocator */
1313 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1316 int nr_pages
= 1 << order
;
1317 struct page
*p
= page
+ 1;
1319 /* we rely on prep_new_huge_page to set the destructor */
1320 set_compound_order(page
, order
);
1321 __ClearPageReserved(page
);
1322 __SetPageHead(page
);
1323 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1325 * For gigantic hugepages allocated through bootmem at
1326 * boot, it's safer to be consistent with the not-gigantic
1327 * hugepages and clear the PG_reserved bit from all tail pages
1328 * too. Otherwse drivers using get_user_pages() to access tail
1329 * pages may get the reference counting wrong if they see
1330 * PG_reserved set on a tail page (despite the head page not
1331 * having PG_reserved set). Enforcing this consistency between
1332 * head and tail pages allows drivers to optimize away a check
1333 * on the head page when they need know if put_page() is needed
1334 * after get_user_pages().
1336 __ClearPageReserved(p
);
1337 set_page_count(p
, 0);
1338 set_compound_head(p
, page
);
1340 atomic_set(compound_mapcount_ptr(page
), -1);
1344 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1345 * transparent huge pages. See the PageTransHuge() documentation for more
1348 int PageHuge(struct page
*page
)
1350 if (!PageCompound(page
))
1353 page
= compound_head(page
);
1354 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1356 EXPORT_SYMBOL_GPL(PageHuge
);
1359 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1360 * normal or transparent huge pages.
1362 int PageHeadHuge(struct page
*page_head
)
1364 if (!PageHead(page_head
))
1367 return get_compound_page_dtor(page_head
) == free_huge_page
;
1370 pgoff_t
__basepage_index(struct page
*page
)
1372 struct page
*page_head
= compound_head(page
);
1373 pgoff_t index
= page_index(page_head
);
1374 unsigned long compound_idx
;
1376 if (!PageHuge(page_head
))
1377 return page_index(page
);
1379 if (compound_order(page_head
) >= MAX_ORDER
)
1380 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1382 compound_idx
= page
- page_head
;
1384 return (index
<< compound_order(page_head
)) + compound_idx
;
1387 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
1391 page
= __alloc_pages_node(nid
,
1392 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
1393 __GFP_RETRY_MAYFAIL
|__GFP_NOWARN
,
1394 huge_page_order(h
));
1396 prep_new_huge_page(h
, page
, nid
);
1402 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1408 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1409 page
= alloc_fresh_huge_page_node(h
, node
);
1417 count_vm_event(HTLB_BUDDY_PGALLOC
);
1419 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1425 * Free huge page from pool from next node to free.
1426 * Attempt to keep persistent huge pages more or less
1427 * balanced over allowed nodes.
1428 * Called with hugetlb_lock locked.
1430 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1436 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1438 * If we're returning unused surplus pages, only examine
1439 * nodes with surplus pages.
1441 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1442 !list_empty(&h
->hugepage_freelists
[node
])) {
1444 list_entry(h
->hugepage_freelists
[node
].next
,
1446 list_del(&page
->lru
);
1447 h
->free_huge_pages
--;
1448 h
->free_huge_pages_node
[node
]--;
1450 h
->surplus_huge_pages
--;
1451 h
->surplus_huge_pages_node
[node
]--;
1453 update_and_free_page(h
, page
);
1463 * Dissolve a given free hugepage into free buddy pages. This function does
1464 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1465 * number of free hugepages would be reduced below the number of reserved
1468 int dissolve_free_huge_page(struct page
*page
)
1472 spin_lock(&hugetlb_lock
);
1473 if (PageHuge(page
) && !page_count(page
)) {
1474 struct page
*head
= compound_head(page
);
1475 struct hstate
*h
= page_hstate(head
);
1476 int nid
= page_to_nid(head
);
1477 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0) {
1482 * Move PageHWPoison flag from head page to the raw error page,
1483 * which makes any subpages rather than the error page reusable.
1485 if (PageHWPoison(head
) && page
!= head
) {
1486 SetPageHWPoison(page
);
1487 ClearPageHWPoison(head
);
1489 list_del(&head
->lru
);
1490 h
->free_huge_pages
--;
1491 h
->free_huge_pages_node
[nid
]--;
1492 h
->max_huge_pages
--;
1493 update_and_free_page(h
, head
);
1496 spin_unlock(&hugetlb_lock
);
1501 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1502 * make specified memory blocks removable from the system.
1503 * Note that this will dissolve a free gigantic hugepage completely, if any
1504 * part of it lies within the given range.
1505 * Also note that if dissolve_free_huge_page() returns with an error, all
1506 * free hugepages that were dissolved before that error are lost.
1508 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1514 if (!hugepages_supported())
1517 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1518 page
= pfn_to_page(pfn
);
1519 if (PageHuge(page
) && !page_count(page
)) {
1520 rc
= dissolve_free_huge_page(page
);
1529 static struct page
*__hugetlb_alloc_buddy_huge_page(struct hstate
*h
,
1530 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
)
1532 int order
= huge_page_order(h
);
1534 gfp_mask
|= __GFP_COMP
|__GFP_RETRY_MAYFAIL
|__GFP_NOWARN
;
1535 if (nid
== NUMA_NO_NODE
)
1536 nid
= numa_mem_id();
1537 return __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1540 static struct page
*__alloc_buddy_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1541 int nid
, nodemask_t
*nmask
)
1546 if (hstate_is_gigantic(h
))
1550 * Assume we will successfully allocate the surplus page to
1551 * prevent racing processes from causing the surplus to exceed
1554 * This however introduces a different race, where a process B
1555 * tries to grow the static hugepage pool while alloc_pages() is
1556 * called by process A. B will only examine the per-node
1557 * counters in determining if surplus huge pages can be
1558 * converted to normal huge pages in adjust_pool_surplus(). A
1559 * won't be able to increment the per-node counter, until the
1560 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1561 * no more huge pages can be converted from surplus to normal
1562 * state (and doesn't try to convert again). Thus, we have a
1563 * case where a surplus huge page exists, the pool is grown, and
1564 * the surplus huge page still exists after, even though it
1565 * should just have been converted to a normal huge page. This
1566 * does not leak memory, though, as the hugepage will be freed
1567 * once it is out of use. It also does not allow the counters to
1568 * go out of whack in adjust_pool_surplus() as we don't modify
1569 * the node values until we've gotten the hugepage and only the
1570 * per-node value is checked there.
1572 spin_lock(&hugetlb_lock
);
1573 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1574 spin_unlock(&hugetlb_lock
);
1578 h
->surplus_huge_pages
++;
1580 spin_unlock(&hugetlb_lock
);
1582 page
= __hugetlb_alloc_buddy_huge_page(h
, gfp_mask
, nid
, nmask
);
1584 spin_lock(&hugetlb_lock
);
1586 INIT_LIST_HEAD(&page
->lru
);
1587 r_nid
= page_to_nid(page
);
1588 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1589 set_hugetlb_cgroup(page
, NULL
);
1591 * We incremented the global counters already
1593 h
->nr_huge_pages_node
[r_nid
]++;
1594 h
->surplus_huge_pages_node
[r_nid
]++;
1595 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1598 h
->surplus_huge_pages
--;
1599 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1601 spin_unlock(&hugetlb_lock
);
1607 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1610 struct page
*__alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1611 struct vm_area_struct
*vma
, unsigned long addr
)
1614 struct mempolicy
*mpol
;
1615 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1617 nodemask_t
*nodemask
;
1619 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1620 page
= __alloc_buddy_huge_page(h
, gfp_mask
, nid
, nodemask
);
1621 mpol_cond_put(mpol
);
1627 * This allocation function is useful in the context where vma is irrelevant.
1628 * E.g. soft-offlining uses this function because it only cares physical
1629 * address of error page.
1631 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1633 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1634 struct page
*page
= NULL
;
1636 if (nid
!= NUMA_NO_NODE
)
1637 gfp_mask
|= __GFP_THISNODE
;
1639 spin_lock(&hugetlb_lock
);
1640 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1641 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1642 spin_unlock(&hugetlb_lock
);
1645 page
= __alloc_buddy_huge_page(h
, gfp_mask
, nid
, NULL
);
1651 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1654 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1656 spin_lock(&hugetlb_lock
);
1657 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1660 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1662 spin_unlock(&hugetlb_lock
);
1666 spin_unlock(&hugetlb_lock
);
1668 /* No reservations, try to overcommit */
1670 return __alloc_buddy_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1674 * Increase the hugetlb pool such that it can accommodate a reservation
1677 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1679 struct list_head surplus_list
;
1680 struct page
*page
, *tmp
;
1682 int needed
, allocated
;
1683 bool alloc_ok
= true;
1685 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1687 h
->resv_huge_pages
+= delta
;
1692 INIT_LIST_HEAD(&surplus_list
);
1696 spin_unlock(&hugetlb_lock
);
1697 for (i
= 0; i
< needed
; i
++) {
1698 page
= __alloc_buddy_huge_page(h
, htlb_alloc_mask(h
),
1699 NUMA_NO_NODE
, NULL
);
1704 list_add(&page
->lru
, &surplus_list
);
1710 * After retaking hugetlb_lock, we need to recalculate 'needed'
1711 * because either resv_huge_pages or free_huge_pages may have changed.
1713 spin_lock(&hugetlb_lock
);
1714 needed
= (h
->resv_huge_pages
+ delta
) -
1715 (h
->free_huge_pages
+ allocated
);
1720 * We were not able to allocate enough pages to
1721 * satisfy the entire reservation so we free what
1722 * we've allocated so far.
1727 * The surplus_list now contains _at_least_ the number of extra pages
1728 * needed to accommodate the reservation. Add the appropriate number
1729 * of pages to the hugetlb pool and free the extras back to the buddy
1730 * allocator. Commit the entire reservation here to prevent another
1731 * process from stealing the pages as they are added to the pool but
1732 * before they are reserved.
1734 needed
+= allocated
;
1735 h
->resv_huge_pages
+= delta
;
1738 /* Free the needed pages to the hugetlb pool */
1739 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1743 * This page is now managed by the hugetlb allocator and has
1744 * no users -- drop the buddy allocator's reference.
1746 put_page_testzero(page
);
1747 VM_BUG_ON_PAGE(page_count(page
), page
);
1748 enqueue_huge_page(h
, page
);
1751 spin_unlock(&hugetlb_lock
);
1753 /* Free unnecessary surplus pages to the buddy allocator */
1754 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1756 spin_lock(&hugetlb_lock
);
1762 * This routine has two main purposes:
1763 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1764 * in unused_resv_pages. This corresponds to the prior adjustments made
1765 * to the associated reservation map.
1766 * 2) Free any unused surplus pages that may have been allocated to satisfy
1767 * the reservation. As many as unused_resv_pages may be freed.
1769 * Called with hugetlb_lock held. However, the lock could be dropped (and
1770 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1771 * we must make sure nobody else can claim pages we are in the process of
1772 * freeing. Do this by ensuring resv_huge_page always is greater than the
1773 * number of huge pages we plan to free when dropping the lock.
1775 static void return_unused_surplus_pages(struct hstate
*h
,
1776 unsigned long unused_resv_pages
)
1778 unsigned long nr_pages
;
1780 /* Cannot return gigantic pages currently */
1781 if (hstate_is_gigantic(h
))
1785 * Part (or even all) of the reservation could have been backed
1786 * by pre-allocated pages. Only free surplus pages.
1788 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1791 * We want to release as many surplus pages as possible, spread
1792 * evenly across all nodes with memory. Iterate across these nodes
1793 * until we can no longer free unreserved surplus pages. This occurs
1794 * when the nodes with surplus pages have no free pages.
1795 * free_pool_huge_page() will balance the the freed pages across the
1796 * on-line nodes with memory and will handle the hstate accounting.
1798 * Note that we decrement resv_huge_pages as we free the pages. If
1799 * we drop the lock, resv_huge_pages will still be sufficiently large
1800 * to cover subsequent pages we may free.
1802 while (nr_pages
--) {
1803 h
->resv_huge_pages
--;
1804 unused_resv_pages
--;
1805 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1807 cond_resched_lock(&hugetlb_lock
);
1811 /* Fully uncommit the reservation */
1812 h
->resv_huge_pages
-= unused_resv_pages
;
1817 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1818 * are used by the huge page allocation routines to manage reservations.
1820 * vma_needs_reservation is called to determine if the huge page at addr
1821 * within the vma has an associated reservation. If a reservation is
1822 * needed, the value 1 is returned. The caller is then responsible for
1823 * managing the global reservation and subpool usage counts. After
1824 * the huge page has been allocated, vma_commit_reservation is called
1825 * to add the page to the reservation map. If the page allocation fails,
1826 * the reservation must be ended instead of committed. vma_end_reservation
1827 * is called in such cases.
1829 * In the normal case, vma_commit_reservation returns the same value
1830 * as the preceding vma_needs_reservation call. The only time this
1831 * is not the case is if a reserve map was changed between calls. It
1832 * is the responsibility of the caller to notice the difference and
1833 * take appropriate action.
1835 * vma_add_reservation is used in error paths where a reservation must
1836 * be restored when a newly allocated huge page must be freed. It is
1837 * to be called after calling vma_needs_reservation to determine if a
1838 * reservation exists.
1840 enum vma_resv_mode
{
1846 static long __vma_reservation_common(struct hstate
*h
,
1847 struct vm_area_struct
*vma
, unsigned long addr
,
1848 enum vma_resv_mode mode
)
1850 struct resv_map
*resv
;
1854 resv
= vma_resv_map(vma
);
1858 idx
= vma_hugecache_offset(h
, vma
, addr
);
1860 case VMA_NEEDS_RESV
:
1861 ret
= region_chg(resv
, idx
, idx
+ 1);
1863 case VMA_COMMIT_RESV
:
1864 ret
= region_add(resv
, idx
, idx
+ 1);
1867 region_abort(resv
, idx
, idx
+ 1);
1871 if (vma
->vm_flags
& VM_MAYSHARE
)
1872 ret
= region_add(resv
, idx
, idx
+ 1);
1874 region_abort(resv
, idx
, idx
+ 1);
1875 ret
= region_del(resv
, idx
, idx
+ 1);
1882 if (vma
->vm_flags
& VM_MAYSHARE
)
1884 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
1886 * In most cases, reserves always exist for private mappings.
1887 * However, a file associated with mapping could have been
1888 * hole punched or truncated after reserves were consumed.
1889 * As subsequent fault on such a range will not use reserves.
1890 * Subtle - The reserve map for private mappings has the
1891 * opposite meaning than that of shared mappings. If NO
1892 * entry is in the reserve map, it means a reservation exists.
1893 * If an entry exists in the reserve map, it means the
1894 * reservation has already been consumed. As a result, the
1895 * return value of this routine is the opposite of the
1896 * value returned from reserve map manipulation routines above.
1904 return ret
< 0 ? ret
: 0;
1907 static long vma_needs_reservation(struct hstate
*h
,
1908 struct vm_area_struct
*vma
, unsigned long addr
)
1910 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
1913 static long vma_commit_reservation(struct hstate
*h
,
1914 struct vm_area_struct
*vma
, unsigned long addr
)
1916 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
1919 static void vma_end_reservation(struct hstate
*h
,
1920 struct vm_area_struct
*vma
, unsigned long addr
)
1922 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
1925 static long vma_add_reservation(struct hstate
*h
,
1926 struct vm_area_struct
*vma
, unsigned long addr
)
1928 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
1932 * This routine is called to restore a reservation on error paths. In the
1933 * specific error paths, a huge page was allocated (via alloc_huge_page)
1934 * and is about to be freed. If a reservation for the page existed,
1935 * alloc_huge_page would have consumed the reservation and set PagePrivate
1936 * in the newly allocated page. When the page is freed via free_huge_page,
1937 * the global reservation count will be incremented if PagePrivate is set.
1938 * However, free_huge_page can not adjust the reserve map. Adjust the
1939 * reserve map here to be consistent with global reserve count adjustments
1940 * to be made by free_huge_page.
1942 static void restore_reserve_on_error(struct hstate
*h
,
1943 struct vm_area_struct
*vma
, unsigned long address
,
1946 if (unlikely(PagePrivate(page
))) {
1947 long rc
= vma_needs_reservation(h
, vma
, address
);
1949 if (unlikely(rc
< 0)) {
1951 * Rare out of memory condition in reserve map
1952 * manipulation. Clear PagePrivate so that
1953 * global reserve count will not be incremented
1954 * by free_huge_page. This will make it appear
1955 * as though the reservation for this page was
1956 * consumed. This may prevent the task from
1957 * faulting in the page at a later time. This
1958 * is better than inconsistent global huge page
1959 * accounting of reserve counts.
1961 ClearPagePrivate(page
);
1963 rc
= vma_add_reservation(h
, vma
, address
);
1964 if (unlikely(rc
< 0))
1966 * See above comment about rare out of
1969 ClearPagePrivate(page
);
1971 vma_end_reservation(h
, vma
, address
);
1975 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1976 unsigned long addr
, int avoid_reserve
)
1978 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1979 struct hstate
*h
= hstate_vma(vma
);
1981 long map_chg
, map_commit
;
1984 struct hugetlb_cgroup
*h_cg
;
1986 idx
= hstate_index(h
);
1988 * Examine the region/reserve map to determine if the process
1989 * has a reservation for the page to be allocated. A return
1990 * code of zero indicates a reservation exists (no change).
1992 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
1994 return ERR_PTR(-ENOMEM
);
1997 * Processes that did not create the mapping will have no
1998 * reserves as indicated by the region/reserve map. Check
1999 * that the allocation will not exceed the subpool limit.
2000 * Allocations for MAP_NORESERVE mappings also need to be
2001 * checked against any subpool limit.
2003 if (map_chg
|| avoid_reserve
) {
2004 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2006 vma_end_reservation(h
, vma
, addr
);
2007 return ERR_PTR(-ENOSPC
);
2011 * Even though there was no reservation in the region/reserve
2012 * map, there could be reservations associated with the
2013 * subpool that can be used. This would be indicated if the
2014 * return value of hugepage_subpool_get_pages() is zero.
2015 * However, if avoid_reserve is specified we still avoid even
2016 * the subpool reservations.
2022 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2024 goto out_subpool_put
;
2026 spin_lock(&hugetlb_lock
);
2028 * glb_chg is passed to indicate whether or not a page must be taken
2029 * from the global free pool (global change). gbl_chg == 0 indicates
2030 * a reservation exists for the allocation.
2032 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2034 spin_unlock(&hugetlb_lock
);
2035 page
= __alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2037 goto out_uncharge_cgroup
;
2038 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2039 SetPagePrivate(page
);
2040 h
->resv_huge_pages
--;
2042 spin_lock(&hugetlb_lock
);
2043 list_move(&page
->lru
, &h
->hugepage_activelist
);
2046 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2047 spin_unlock(&hugetlb_lock
);
2049 set_page_private(page
, (unsigned long)spool
);
2051 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2052 if (unlikely(map_chg
> map_commit
)) {
2054 * The page was added to the reservation map between
2055 * vma_needs_reservation and vma_commit_reservation.
2056 * This indicates a race with hugetlb_reserve_pages.
2057 * Adjust for the subpool count incremented above AND
2058 * in hugetlb_reserve_pages for the same page. Also,
2059 * the reservation count added in hugetlb_reserve_pages
2060 * no longer applies.
2064 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2065 hugetlb_acct_memory(h
, -rsv_adjust
);
2069 out_uncharge_cgroup
:
2070 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2072 if (map_chg
|| avoid_reserve
)
2073 hugepage_subpool_put_pages(spool
, 1);
2074 vma_end_reservation(h
, vma
, addr
);
2075 return ERR_PTR(-ENOSPC
);
2079 * alloc_huge_page()'s wrapper which simply returns the page if allocation
2080 * succeeds, otherwise NULL. This function is called from new_vma_page(),
2081 * where no ERR_VALUE is expected to be returned.
2083 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
2084 unsigned long addr
, int avoid_reserve
)
2086 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
2092 int alloc_bootmem_huge_page(struct hstate
*h
)
2093 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2094 int __alloc_bootmem_huge_page(struct hstate
*h
)
2096 struct huge_bootmem_page
*m
;
2099 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2102 addr
= memblock_virt_alloc_try_nid_nopanic(
2103 huge_page_size(h
), huge_page_size(h
),
2104 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
2107 * Use the beginning of the huge page to store the
2108 * huge_bootmem_page struct (until gather_bootmem
2109 * puts them into the mem_map).
2118 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2119 /* Put them into a private list first because mem_map is not up yet */
2120 list_add(&m
->list
, &huge_boot_pages
);
2125 static void __init
prep_compound_huge_page(struct page
*page
,
2128 if (unlikely(order
> (MAX_ORDER
- 1)))
2129 prep_compound_gigantic_page(page
, order
);
2131 prep_compound_page(page
, order
);
2134 /* Put bootmem huge pages into the standard lists after mem_map is up */
2135 static void __init
gather_bootmem_prealloc(void)
2137 struct huge_bootmem_page
*m
;
2139 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2140 struct hstate
*h
= m
->hstate
;
2143 #ifdef CONFIG_HIGHMEM
2144 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
2145 memblock_free_late(__pa(m
),
2146 sizeof(struct huge_bootmem_page
));
2148 page
= virt_to_page(m
);
2150 WARN_ON(page_count(page
) != 1);
2151 prep_compound_huge_page(page
, h
->order
);
2152 WARN_ON(PageReserved(page
));
2153 prep_new_huge_page(h
, page
, page_to_nid(page
));
2155 * If we had gigantic hugepages allocated at boot time, we need
2156 * to restore the 'stolen' pages to totalram_pages in order to
2157 * fix confusing memory reports from free(1) and another
2158 * side-effects, like CommitLimit going negative.
2160 if (hstate_is_gigantic(h
))
2161 adjust_managed_page_count(page
, 1 << h
->order
);
2165 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2169 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2170 if (hstate_is_gigantic(h
)) {
2171 if (!alloc_bootmem_huge_page(h
))
2173 } else if (!alloc_fresh_huge_page(h
,
2174 &node_states
[N_MEMORY
]))
2178 if (i
< h
->max_huge_pages
) {
2181 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2182 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2183 h
->max_huge_pages
, buf
, i
);
2184 h
->max_huge_pages
= i
;
2188 static void __init
hugetlb_init_hstates(void)
2192 for_each_hstate(h
) {
2193 if (minimum_order
> huge_page_order(h
))
2194 minimum_order
= huge_page_order(h
);
2196 /* oversize hugepages were init'ed in early boot */
2197 if (!hstate_is_gigantic(h
))
2198 hugetlb_hstate_alloc_pages(h
);
2200 VM_BUG_ON(minimum_order
== UINT_MAX
);
2203 static void __init
report_hugepages(void)
2207 for_each_hstate(h
) {
2210 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2211 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2212 buf
, h
->free_huge_pages
);
2216 #ifdef CONFIG_HIGHMEM
2217 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2218 nodemask_t
*nodes_allowed
)
2222 if (hstate_is_gigantic(h
))
2225 for_each_node_mask(i
, *nodes_allowed
) {
2226 struct page
*page
, *next
;
2227 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2228 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2229 if (count
>= h
->nr_huge_pages
)
2231 if (PageHighMem(page
))
2233 list_del(&page
->lru
);
2234 update_and_free_page(h
, page
);
2235 h
->free_huge_pages
--;
2236 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2241 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2242 nodemask_t
*nodes_allowed
)
2248 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2249 * balanced by operating on them in a round-robin fashion.
2250 * Returns 1 if an adjustment was made.
2252 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2257 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2260 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2261 if (h
->surplus_huge_pages_node
[node
])
2265 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2266 if (h
->surplus_huge_pages_node
[node
] <
2267 h
->nr_huge_pages_node
[node
])
2274 h
->surplus_huge_pages
+= delta
;
2275 h
->surplus_huge_pages_node
[node
] += delta
;
2279 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2280 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
2281 nodemask_t
*nodes_allowed
)
2283 unsigned long min_count
, ret
;
2285 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
2286 return h
->max_huge_pages
;
2289 * Increase the pool size
2290 * First take pages out of surplus state. Then make up the
2291 * remaining difference by allocating fresh huge pages.
2293 * We might race with __alloc_buddy_huge_page() here and be unable
2294 * to convert a surplus huge page to a normal huge page. That is
2295 * not critical, though, it just means the overall size of the
2296 * pool might be one hugepage larger than it needs to be, but
2297 * within all the constraints specified by the sysctls.
2299 spin_lock(&hugetlb_lock
);
2300 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2301 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2305 while (count
> persistent_huge_pages(h
)) {
2307 * If this allocation races such that we no longer need the
2308 * page, free_huge_page will handle it by freeing the page
2309 * and reducing the surplus.
2311 spin_unlock(&hugetlb_lock
);
2313 /* yield cpu to avoid soft lockup */
2316 if (hstate_is_gigantic(h
))
2317 ret
= alloc_fresh_gigantic_page(h
, nodes_allowed
);
2319 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
2320 spin_lock(&hugetlb_lock
);
2324 /* Bail for signals. Probably ctrl-c from user */
2325 if (signal_pending(current
))
2330 * Decrease the pool size
2331 * First return free pages to the buddy allocator (being careful
2332 * to keep enough around to satisfy reservations). Then place
2333 * pages into surplus state as needed so the pool will shrink
2334 * to the desired size as pages become free.
2336 * By placing pages into the surplus state independent of the
2337 * overcommit value, we are allowing the surplus pool size to
2338 * exceed overcommit. There are few sane options here. Since
2339 * __alloc_buddy_huge_page() is checking the global counter,
2340 * though, we'll note that we're not allowed to exceed surplus
2341 * and won't grow the pool anywhere else. Not until one of the
2342 * sysctls are changed, or the surplus pages go out of use.
2344 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2345 min_count
= max(count
, min_count
);
2346 try_to_free_low(h
, min_count
, nodes_allowed
);
2347 while (min_count
< persistent_huge_pages(h
)) {
2348 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2350 cond_resched_lock(&hugetlb_lock
);
2352 while (count
< persistent_huge_pages(h
)) {
2353 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2357 ret
= persistent_huge_pages(h
);
2358 spin_unlock(&hugetlb_lock
);
2362 #define HSTATE_ATTR_RO(_name) \
2363 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2365 #define HSTATE_ATTR(_name) \
2366 static struct kobj_attribute _name##_attr = \
2367 __ATTR(_name, 0644, _name##_show, _name##_store)
2369 static struct kobject
*hugepages_kobj
;
2370 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2372 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2374 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2378 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2379 if (hstate_kobjs
[i
] == kobj
) {
2381 *nidp
= NUMA_NO_NODE
;
2385 return kobj_to_node_hstate(kobj
, nidp
);
2388 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2389 struct kobj_attribute
*attr
, char *buf
)
2392 unsigned long nr_huge_pages
;
2395 h
= kobj_to_hstate(kobj
, &nid
);
2396 if (nid
== NUMA_NO_NODE
)
2397 nr_huge_pages
= h
->nr_huge_pages
;
2399 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2401 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2404 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2405 struct hstate
*h
, int nid
,
2406 unsigned long count
, size_t len
)
2409 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
2411 if (hstate_is_gigantic(h
) && !gigantic_page_supported()) {
2416 if (nid
== NUMA_NO_NODE
) {
2418 * global hstate attribute
2420 if (!(obey_mempolicy
&&
2421 init_nodemask_of_mempolicy(nodes_allowed
))) {
2422 NODEMASK_FREE(nodes_allowed
);
2423 nodes_allowed
= &node_states
[N_MEMORY
];
2425 } else if (nodes_allowed
) {
2427 * per node hstate attribute: adjust count to global,
2428 * but restrict alloc/free to the specified node.
2430 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2431 init_nodemask_of_node(nodes_allowed
, nid
);
2433 nodes_allowed
= &node_states
[N_MEMORY
];
2435 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
2437 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2438 NODEMASK_FREE(nodes_allowed
);
2442 NODEMASK_FREE(nodes_allowed
);
2446 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2447 struct kobject
*kobj
, const char *buf
,
2451 unsigned long count
;
2455 err
= kstrtoul(buf
, 10, &count
);
2459 h
= kobj_to_hstate(kobj
, &nid
);
2460 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2463 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2464 struct kobj_attribute
*attr
, char *buf
)
2466 return nr_hugepages_show_common(kobj
, attr
, buf
);
2469 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2470 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2472 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2474 HSTATE_ATTR(nr_hugepages
);
2479 * hstate attribute for optionally mempolicy-based constraint on persistent
2480 * huge page alloc/free.
2482 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2483 struct kobj_attribute
*attr
, char *buf
)
2485 return nr_hugepages_show_common(kobj
, attr
, buf
);
2488 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2489 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2491 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2493 HSTATE_ATTR(nr_hugepages_mempolicy
);
2497 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2498 struct kobj_attribute
*attr
, char *buf
)
2500 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2501 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2504 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2505 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2508 unsigned long input
;
2509 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2511 if (hstate_is_gigantic(h
))
2514 err
= kstrtoul(buf
, 10, &input
);
2518 spin_lock(&hugetlb_lock
);
2519 h
->nr_overcommit_huge_pages
= input
;
2520 spin_unlock(&hugetlb_lock
);
2524 HSTATE_ATTR(nr_overcommit_hugepages
);
2526 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2527 struct kobj_attribute
*attr
, char *buf
)
2530 unsigned long free_huge_pages
;
2533 h
= kobj_to_hstate(kobj
, &nid
);
2534 if (nid
== NUMA_NO_NODE
)
2535 free_huge_pages
= h
->free_huge_pages
;
2537 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2539 return sprintf(buf
, "%lu\n", free_huge_pages
);
2541 HSTATE_ATTR_RO(free_hugepages
);
2543 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2544 struct kobj_attribute
*attr
, char *buf
)
2546 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2547 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2549 HSTATE_ATTR_RO(resv_hugepages
);
2551 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2552 struct kobj_attribute
*attr
, char *buf
)
2555 unsigned long surplus_huge_pages
;
2558 h
= kobj_to_hstate(kobj
, &nid
);
2559 if (nid
== NUMA_NO_NODE
)
2560 surplus_huge_pages
= h
->surplus_huge_pages
;
2562 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2564 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2566 HSTATE_ATTR_RO(surplus_hugepages
);
2568 static struct attribute
*hstate_attrs
[] = {
2569 &nr_hugepages_attr
.attr
,
2570 &nr_overcommit_hugepages_attr
.attr
,
2571 &free_hugepages_attr
.attr
,
2572 &resv_hugepages_attr
.attr
,
2573 &surplus_hugepages_attr
.attr
,
2575 &nr_hugepages_mempolicy_attr
.attr
,
2580 static const struct attribute_group hstate_attr_group
= {
2581 .attrs
= hstate_attrs
,
2584 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2585 struct kobject
**hstate_kobjs
,
2586 const struct attribute_group
*hstate_attr_group
)
2589 int hi
= hstate_index(h
);
2591 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2592 if (!hstate_kobjs
[hi
])
2595 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2597 kobject_put(hstate_kobjs
[hi
]);
2602 static void __init
hugetlb_sysfs_init(void)
2607 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2608 if (!hugepages_kobj
)
2611 for_each_hstate(h
) {
2612 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2613 hstate_kobjs
, &hstate_attr_group
);
2615 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2622 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2623 * with node devices in node_devices[] using a parallel array. The array
2624 * index of a node device or _hstate == node id.
2625 * This is here to avoid any static dependency of the node device driver, in
2626 * the base kernel, on the hugetlb module.
2628 struct node_hstate
{
2629 struct kobject
*hugepages_kobj
;
2630 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2632 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2635 * A subset of global hstate attributes for node devices
2637 static struct attribute
*per_node_hstate_attrs
[] = {
2638 &nr_hugepages_attr
.attr
,
2639 &free_hugepages_attr
.attr
,
2640 &surplus_hugepages_attr
.attr
,
2644 static const struct attribute_group per_node_hstate_attr_group
= {
2645 .attrs
= per_node_hstate_attrs
,
2649 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2650 * Returns node id via non-NULL nidp.
2652 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2656 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2657 struct node_hstate
*nhs
= &node_hstates
[nid
];
2659 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2660 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2672 * Unregister hstate attributes from a single node device.
2673 * No-op if no hstate attributes attached.
2675 static void hugetlb_unregister_node(struct node
*node
)
2678 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2680 if (!nhs
->hugepages_kobj
)
2681 return; /* no hstate attributes */
2683 for_each_hstate(h
) {
2684 int idx
= hstate_index(h
);
2685 if (nhs
->hstate_kobjs
[idx
]) {
2686 kobject_put(nhs
->hstate_kobjs
[idx
]);
2687 nhs
->hstate_kobjs
[idx
] = NULL
;
2691 kobject_put(nhs
->hugepages_kobj
);
2692 nhs
->hugepages_kobj
= NULL
;
2697 * Register hstate attributes for a single node device.
2698 * No-op if attributes already registered.
2700 static void hugetlb_register_node(struct node
*node
)
2703 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2706 if (nhs
->hugepages_kobj
)
2707 return; /* already allocated */
2709 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2711 if (!nhs
->hugepages_kobj
)
2714 for_each_hstate(h
) {
2715 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2717 &per_node_hstate_attr_group
);
2719 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2720 h
->name
, node
->dev
.id
);
2721 hugetlb_unregister_node(node
);
2728 * hugetlb init time: register hstate attributes for all registered node
2729 * devices of nodes that have memory. All on-line nodes should have
2730 * registered their associated device by this time.
2732 static void __init
hugetlb_register_all_nodes(void)
2736 for_each_node_state(nid
, N_MEMORY
) {
2737 struct node
*node
= node_devices
[nid
];
2738 if (node
->dev
.id
== nid
)
2739 hugetlb_register_node(node
);
2743 * Let the node device driver know we're here so it can
2744 * [un]register hstate attributes on node hotplug.
2746 register_hugetlbfs_with_node(hugetlb_register_node
,
2747 hugetlb_unregister_node
);
2749 #else /* !CONFIG_NUMA */
2751 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2759 static void hugetlb_register_all_nodes(void) { }
2763 static int __init
hugetlb_init(void)
2767 if (!hugepages_supported())
2770 if (!size_to_hstate(default_hstate_size
)) {
2771 if (default_hstate_size
!= 0) {
2772 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
2773 default_hstate_size
, HPAGE_SIZE
);
2776 default_hstate_size
= HPAGE_SIZE
;
2777 if (!size_to_hstate(default_hstate_size
))
2778 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2780 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2781 if (default_hstate_max_huge_pages
) {
2782 if (!default_hstate
.max_huge_pages
)
2783 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2786 hugetlb_init_hstates();
2787 gather_bootmem_prealloc();
2790 hugetlb_sysfs_init();
2791 hugetlb_register_all_nodes();
2792 hugetlb_cgroup_file_init();
2795 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2797 num_fault_mutexes
= 1;
2799 hugetlb_fault_mutex_table
=
2800 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2801 BUG_ON(!hugetlb_fault_mutex_table
);
2803 for (i
= 0; i
< num_fault_mutexes
; i
++)
2804 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2807 subsys_initcall(hugetlb_init
);
2809 /* Should be called on processing a hugepagesz=... option */
2810 void __init
hugetlb_bad_size(void)
2812 parsed_valid_hugepagesz
= false;
2815 void __init
hugetlb_add_hstate(unsigned int order
)
2820 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2821 pr_warn("hugepagesz= specified twice, ignoring\n");
2824 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2826 h
= &hstates
[hugetlb_max_hstate
++];
2828 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2829 h
->nr_huge_pages
= 0;
2830 h
->free_huge_pages
= 0;
2831 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2832 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2833 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2834 h
->next_nid_to_alloc
= first_memory_node
;
2835 h
->next_nid_to_free
= first_memory_node
;
2836 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2837 huge_page_size(h
)/1024);
2842 static int __init
hugetlb_nrpages_setup(char *s
)
2845 static unsigned long *last_mhp
;
2847 if (!parsed_valid_hugepagesz
) {
2848 pr_warn("hugepages = %s preceded by "
2849 "an unsupported hugepagesz, ignoring\n", s
);
2850 parsed_valid_hugepagesz
= true;
2854 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2855 * so this hugepages= parameter goes to the "default hstate".
2857 else if (!hugetlb_max_hstate
)
2858 mhp
= &default_hstate_max_huge_pages
;
2860 mhp
= &parsed_hstate
->max_huge_pages
;
2862 if (mhp
== last_mhp
) {
2863 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2867 if (sscanf(s
, "%lu", mhp
) <= 0)
2871 * Global state is always initialized later in hugetlb_init.
2872 * But we need to allocate >= MAX_ORDER hstates here early to still
2873 * use the bootmem allocator.
2875 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2876 hugetlb_hstate_alloc_pages(parsed_hstate
);
2882 __setup("hugepages=", hugetlb_nrpages_setup
);
2884 static int __init
hugetlb_default_setup(char *s
)
2886 default_hstate_size
= memparse(s
, &s
);
2889 __setup("default_hugepagesz=", hugetlb_default_setup
);
2891 static unsigned int cpuset_mems_nr(unsigned int *array
)
2894 unsigned int nr
= 0;
2896 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2902 #ifdef CONFIG_SYSCTL
2903 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2904 struct ctl_table
*table
, int write
,
2905 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2907 struct hstate
*h
= &default_hstate
;
2908 unsigned long tmp
= h
->max_huge_pages
;
2911 if (!hugepages_supported())
2915 table
->maxlen
= sizeof(unsigned long);
2916 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2921 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
2922 NUMA_NO_NODE
, tmp
, *length
);
2927 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2928 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2931 return hugetlb_sysctl_handler_common(false, table
, write
,
2932 buffer
, length
, ppos
);
2936 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2937 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2939 return hugetlb_sysctl_handler_common(true, table
, write
,
2940 buffer
, length
, ppos
);
2942 #endif /* CONFIG_NUMA */
2944 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2945 void __user
*buffer
,
2946 size_t *length
, loff_t
*ppos
)
2948 struct hstate
*h
= &default_hstate
;
2952 if (!hugepages_supported())
2955 tmp
= h
->nr_overcommit_huge_pages
;
2957 if (write
&& hstate_is_gigantic(h
))
2961 table
->maxlen
= sizeof(unsigned long);
2962 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2967 spin_lock(&hugetlb_lock
);
2968 h
->nr_overcommit_huge_pages
= tmp
;
2969 spin_unlock(&hugetlb_lock
);
2975 #endif /* CONFIG_SYSCTL */
2977 void hugetlb_report_meminfo(struct seq_file
*m
)
2979 struct hstate
*h
= &default_hstate
;
2980 if (!hugepages_supported())
2983 "HugePages_Total: %5lu\n"
2984 "HugePages_Free: %5lu\n"
2985 "HugePages_Rsvd: %5lu\n"
2986 "HugePages_Surp: %5lu\n"
2987 "Hugepagesize: %8lu kB\n",
2991 h
->surplus_huge_pages
,
2992 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2995 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2997 struct hstate
*h
= &default_hstate
;
2998 if (!hugepages_supported())
3001 "Node %d HugePages_Total: %5u\n"
3002 "Node %d HugePages_Free: %5u\n"
3003 "Node %d HugePages_Surp: %5u\n",
3004 nid
, h
->nr_huge_pages_node
[nid
],
3005 nid
, h
->free_huge_pages_node
[nid
],
3006 nid
, h
->surplus_huge_pages_node
[nid
]);
3009 void hugetlb_show_meminfo(void)
3014 if (!hugepages_supported())
3017 for_each_node_state(nid
, N_MEMORY
)
3019 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3021 h
->nr_huge_pages_node
[nid
],
3022 h
->free_huge_pages_node
[nid
],
3023 h
->surplus_huge_pages_node
[nid
],
3024 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3027 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3029 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3030 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3033 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3034 unsigned long hugetlb_total_pages(void)
3037 unsigned long nr_total_pages
= 0;
3040 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3041 return nr_total_pages
;
3044 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3048 spin_lock(&hugetlb_lock
);
3050 * When cpuset is configured, it breaks the strict hugetlb page
3051 * reservation as the accounting is done on a global variable. Such
3052 * reservation is completely rubbish in the presence of cpuset because
3053 * the reservation is not checked against page availability for the
3054 * current cpuset. Application can still potentially OOM'ed by kernel
3055 * with lack of free htlb page in cpuset that the task is in.
3056 * Attempt to enforce strict accounting with cpuset is almost
3057 * impossible (or too ugly) because cpuset is too fluid that
3058 * task or memory node can be dynamically moved between cpusets.
3060 * The change of semantics for shared hugetlb mapping with cpuset is
3061 * undesirable. However, in order to preserve some of the semantics,
3062 * we fall back to check against current free page availability as
3063 * a best attempt and hopefully to minimize the impact of changing
3064 * semantics that cpuset has.
3067 if (gather_surplus_pages(h
, delta
) < 0)
3070 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3071 return_unused_surplus_pages(h
, delta
);
3078 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3081 spin_unlock(&hugetlb_lock
);
3085 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3087 struct resv_map
*resv
= vma_resv_map(vma
);
3090 * This new VMA should share its siblings reservation map if present.
3091 * The VMA will only ever have a valid reservation map pointer where
3092 * it is being copied for another still existing VMA. As that VMA
3093 * has a reference to the reservation map it cannot disappear until
3094 * after this open call completes. It is therefore safe to take a
3095 * new reference here without additional locking.
3097 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3098 kref_get(&resv
->refs
);
3101 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3103 struct hstate
*h
= hstate_vma(vma
);
3104 struct resv_map
*resv
= vma_resv_map(vma
);
3105 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3106 unsigned long reserve
, start
, end
;
3109 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3112 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3113 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3115 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3117 kref_put(&resv
->refs
, resv_map_release
);
3121 * Decrement reserve counts. The global reserve count may be
3122 * adjusted if the subpool has a minimum size.
3124 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3125 hugetlb_acct_memory(h
, -gbl_reserve
);
3129 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3131 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3137 * We cannot handle pagefaults against hugetlb pages at all. They cause
3138 * handle_mm_fault() to try to instantiate regular-sized pages in the
3139 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3142 static int hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3148 const struct vm_operations_struct hugetlb_vm_ops
= {
3149 .fault
= hugetlb_vm_op_fault
,
3150 .open
= hugetlb_vm_op_open
,
3151 .close
= hugetlb_vm_op_close
,
3152 .split
= hugetlb_vm_op_split
,
3155 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3161 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3162 vma
->vm_page_prot
)));
3164 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3165 vma
->vm_page_prot
));
3167 entry
= pte_mkyoung(entry
);
3168 entry
= pte_mkhuge(entry
);
3169 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3174 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3175 unsigned long address
, pte_t
*ptep
)
3179 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3180 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3181 update_mmu_cache(vma
, address
, ptep
);
3184 bool is_hugetlb_entry_migration(pte_t pte
)
3188 if (huge_pte_none(pte
) || pte_present(pte
))
3190 swp
= pte_to_swp_entry(pte
);
3191 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3197 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3201 if (huge_pte_none(pte
) || pte_present(pte
))
3203 swp
= pte_to_swp_entry(pte
);
3204 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3210 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3211 struct vm_area_struct
*vma
)
3213 pte_t
*src_pte
, *dst_pte
, entry
;
3214 struct page
*ptepage
;
3217 struct hstate
*h
= hstate_vma(vma
);
3218 unsigned long sz
= huge_page_size(h
);
3219 unsigned long mmun_start
; /* For mmu_notifiers */
3220 unsigned long mmun_end
; /* For mmu_notifiers */
3223 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3225 mmun_start
= vma
->vm_start
;
3226 mmun_end
= vma
->vm_end
;
3228 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
3230 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3231 spinlock_t
*src_ptl
, *dst_ptl
;
3232 src_pte
= huge_pte_offset(src
, addr
, sz
);
3235 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3241 /* If the pagetables are shared don't copy or take references */
3242 if (dst_pte
== src_pte
)
3245 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3246 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3247 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3248 entry
= huge_ptep_get(src_pte
);
3249 if (huge_pte_none(entry
)) { /* skip none entry */
3251 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3252 is_hugetlb_entry_hwpoisoned(entry
))) {
3253 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3255 if (is_write_migration_entry(swp_entry
) && cow
) {
3257 * COW mappings require pages in both
3258 * parent and child to be set to read.
3260 make_migration_entry_read(&swp_entry
);
3261 entry
= swp_entry_to_pte(swp_entry
);
3262 set_huge_swap_pte_at(src
, addr
, src_pte
,
3265 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3269 * No need to notify as we are downgrading page
3270 * table protection not changing it to point
3273 * See Documentation/vm/mmu_notifier.txt
3275 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3277 entry
= huge_ptep_get(src_pte
);
3278 ptepage
= pte_page(entry
);
3280 page_dup_rmap(ptepage
, true);
3281 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3282 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3284 spin_unlock(src_ptl
);
3285 spin_unlock(dst_ptl
);
3289 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
3294 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3295 unsigned long start
, unsigned long end
,
3296 struct page
*ref_page
)
3298 struct mm_struct
*mm
= vma
->vm_mm
;
3299 unsigned long address
;
3304 struct hstate
*h
= hstate_vma(vma
);
3305 unsigned long sz
= huge_page_size(h
);
3306 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
3307 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
3309 WARN_ON(!is_vm_hugetlb_page(vma
));
3310 BUG_ON(start
& ~huge_page_mask(h
));
3311 BUG_ON(end
& ~huge_page_mask(h
));
3314 * This is a hugetlb vma, all the pte entries should point
3317 tlb_remove_check_page_size_change(tlb
, sz
);
3318 tlb_start_vma(tlb
, vma
);
3319 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3321 for (; address
< end
; address
+= sz
) {
3322 ptep
= huge_pte_offset(mm
, address
, sz
);
3326 ptl
= huge_pte_lock(h
, mm
, ptep
);
3327 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3332 pte
= huge_ptep_get(ptep
);
3333 if (huge_pte_none(pte
)) {
3339 * Migrating hugepage or HWPoisoned hugepage is already
3340 * unmapped and its refcount is dropped, so just clear pte here.
3342 if (unlikely(!pte_present(pte
))) {
3343 huge_pte_clear(mm
, address
, ptep
, sz
);
3348 page
= pte_page(pte
);
3350 * If a reference page is supplied, it is because a specific
3351 * page is being unmapped, not a range. Ensure the page we
3352 * are about to unmap is the actual page of interest.
3355 if (page
!= ref_page
) {
3360 * Mark the VMA as having unmapped its page so that
3361 * future faults in this VMA will fail rather than
3362 * looking like data was lost
3364 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3367 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3368 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3369 if (huge_pte_dirty(pte
))
3370 set_page_dirty(page
);
3372 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3373 page_remove_rmap(page
, true);
3376 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3378 * Bail out after unmapping reference page if supplied
3383 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3384 tlb_end_vma(tlb
, vma
);
3387 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3388 struct vm_area_struct
*vma
, unsigned long start
,
3389 unsigned long end
, struct page
*ref_page
)
3391 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3394 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3395 * test will fail on a vma being torn down, and not grab a page table
3396 * on its way out. We're lucky that the flag has such an appropriate
3397 * name, and can in fact be safely cleared here. We could clear it
3398 * before the __unmap_hugepage_range above, but all that's necessary
3399 * is to clear it before releasing the i_mmap_rwsem. This works
3400 * because in the context this is called, the VMA is about to be
3401 * destroyed and the i_mmap_rwsem is held.
3403 vma
->vm_flags
&= ~VM_MAYSHARE
;
3406 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3407 unsigned long end
, struct page
*ref_page
)
3409 struct mm_struct
*mm
;
3410 struct mmu_gather tlb
;
3414 tlb_gather_mmu(&tlb
, mm
, start
, end
);
3415 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3416 tlb_finish_mmu(&tlb
, start
, end
);
3420 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3421 * mappping it owns the reserve page for. The intention is to unmap the page
3422 * from other VMAs and let the children be SIGKILLed if they are faulting the
3425 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3426 struct page
*page
, unsigned long address
)
3428 struct hstate
*h
= hstate_vma(vma
);
3429 struct vm_area_struct
*iter_vma
;
3430 struct address_space
*mapping
;
3434 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3435 * from page cache lookup which is in HPAGE_SIZE units.
3437 address
= address
& huge_page_mask(h
);
3438 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3440 mapping
= vma
->vm_file
->f_mapping
;
3443 * Take the mapping lock for the duration of the table walk. As
3444 * this mapping should be shared between all the VMAs,
3445 * __unmap_hugepage_range() is called as the lock is already held
3447 i_mmap_lock_write(mapping
);
3448 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3449 /* Do not unmap the current VMA */
3450 if (iter_vma
== vma
)
3454 * Shared VMAs have their own reserves and do not affect
3455 * MAP_PRIVATE accounting but it is possible that a shared
3456 * VMA is using the same page so check and skip such VMAs.
3458 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3462 * Unmap the page from other VMAs without their own reserves.
3463 * They get marked to be SIGKILLed if they fault in these
3464 * areas. This is because a future no-page fault on this VMA
3465 * could insert a zeroed page instead of the data existing
3466 * from the time of fork. This would look like data corruption
3468 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3469 unmap_hugepage_range(iter_vma
, address
,
3470 address
+ huge_page_size(h
), page
);
3472 i_mmap_unlock_write(mapping
);
3476 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3477 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3478 * cannot race with other handlers or page migration.
3479 * Keep the pte_same checks anyway to make transition from the mutex easier.
3481 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3482 unsigned long address
, pte_t
*ptep
,
3483 struct page
*pagecache_page
, spinlock_t
*ptl
)
3486 struct hstate
*h
= hstate_vma(vma
);
3487 struct page
*old_page
, *new_page
;
3488 int ret
= 0, outside_reserve
= 0;
3489 unsigned long mmun_start
; /* For mmu_notifiers */
3490 unsigned long mmun_end
; /* For mmu_notifiers */
3492 pte
= huge_ptep_get(ptep
);
3493 old_page
= pte_page(pte
);
3496 /* If no-one else is actually using this page, avoid the copy
3497 * and just make the page writable */
3498 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3499 page_move_anon_rmap(old_page
, vma
);
3500 set_huge_ptep_writable(vma
, address
, ptep
);
3505 * If the process that created a MAP_PRIVATE mapping is about to
3506 * perform a COW due to a shared page count, attempt to satisfy
3507 * the allocation without using the existing reserves. The pagecache
3508 * page is used to determine if the reserve at this address was
3509 * consumed or not. If reserves were used, a partial faulted mapping
3510 * at the time of fork() could consume its reserves on COW instead
3511 * of the full address range.
3513 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3514 old_page
!= pagecache_page
)
3515 outside_reserve
= 1;
3520 * Drop page table lock as buddy allocator may be called. It will
3521 * be acquired again before returning to the caller, as expected.
3524 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
3526 if (IS_ERR(new_page
)) {
3528 * If a process owning a MAP_PRIVATE mapping fails to COW,
3529 * it is due to references held by a child and an insufficient
3530 * huge page pool. To guarantee the original mappers
3531 * reliability, unmap the page from child processes. The child
3532 * may get SIGKILLed if it later faults.
3534 if (outside_reserve
) {
3536 BUG_ON(huge_pte_none(pte
));
3537 unmap_ref_private(mm
, vma
, old_page
, address
);
3538 BUG_ON(huge_pte_none(pte
));
3540 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
),
3543 pte_same(huge_ptep_get(ptep
), pte
)))
3544 goto retry_avoidcopy
;
3546 * race occurs while re-acquiring page table
3547 * lock, and our job is done.
3552 ret
= (PTR_ERR(new_page
) == -ENOMEM
) ?
3553 VM_FAULT_OOM
: VM_FAULT_SIGBUS
;
3554 goto out_release_old
;
3558 * When the original hugepage is shared one, it does not have
3559 * anon_vma prepared.
3561 if (unlikely(anon_vma_prepare(vma
))) {
3563 goto out_release_all
;
3566 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3567 pages_per_huge_page(h
));
3568 __SetPageUptodate(new_page
);
3569 set_page_huge_active(new_page
);
3571 mmun_start
= address
& huge_page_mask(h
);
3572 mmun_end
= mmun_start
+ huge_page_size(h
);
3573 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3576 * Retake the page table lock to check for racing updates
3577 * before the page tables are altered
3580 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
),
3582 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3583 ClearPagePrivate(new_page
);
3586 huge_ptep_clear_flush(vma
, address
, ptep
);
3587 mmu_notifier_invalidate_range(mm
, mmun_start
, mmun_end
);
3588 set_huge_pte_at(mm
, address
, ptep
,
3589 make_huge_pte(vma
, new_page
, 1));
3590 page_remove_rmap(old_page
, true);
3591 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
3592 /* Make the old page be freed below */
3593 new_page
= old_page
;
3596 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3598 restore_reserve_on_error(h
, vma
, address
, new_page
);
3603 spin_lock(ptl
); /* Caller expects lock to be held */
3607 /* Return the pagecache page at a given address within a VMA */
3608 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3609 struct vm_area_struct
*vma
, unsigned long address
)
3611 struct address_space
*mapping
;
3614 mapping
= vma
->vm_file
->f_mapping
;
3615 idx
= vma_hugecache_offset(h
, vma
, address
);
3617 return find_lock_page(mapping
, idx
);
3621 * Return whether there is a pagecache page to back given address within VMA.
3622 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3624 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3625 struct vm_area_struct
*vma
, unsigned long address
)
3627 struct address_space
*mapping
;
3631 mapping
= vma
->vm_file
->f_mapping
;
3632 idx
= vma_hugecache_offset(h
, vma
, address
);
3634 page
= find_get_page(mapping
, idx
);
3637 return page
!= NULL
;
3640 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3643 struct inode
*inode
= mapping
->host
;
3644 struct hstate
*h
= hstate_inode(inode
);
3645 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3649 ClearPagePrivate(page
);
3651 spin_lock(&inode
->i_lock
);
3652 inode
->i_blocks
+= blocks_per_huge_page(h
);
3653 spin_unlock(&inode
->i_lock
);
3657 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3658 struct address_space
*mapping
, pgoff_t idx
,
3659 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3661 struct hstate
*h
= hstate_vma(vma
);
3662 int ret
= VM_FAULT_SIGBUS
;
3670 * Currently, we are forced to kill the process in the event the
3671 * original mapper has unmapped pages from the child due to a failed
3672 * COW. Warn that such a situation has occurred as it may not be obvious
3674 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3675 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3681 * Use page lock to guard against racing truncation
3682 * before we get page_table_lock.
3685 page
= find_lock_page(mapping
, idx
);
3687 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3692 * Check for page in userfault range
3694 if (userfaultfd_missing(vma
)) {
3696 struct vm_fault vmf
= {
3701 * Hard to debug if it ends up being
3702 * used by a callee that assumes
3703 * something about the other
3704 * uninitialized fields... same as in
3710 * hugetlb_fault_mutex must be dropped before
3711 * handling userfault. Reacquire after handling
3712 * fault to make calling code simpler.
3714 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
,
3716 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3717 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
3718 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3722 page
= alloc_huge_page(vma
, address
, 0);
3724 ret
= PTR_ERR(page
);
3728 ret
= VM_FAULT_SIGBUS
;
3731 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3732 __SetPageUptodate(page
);
3733 set_page_huge_active(page
);
3735 if (vma
->vm_flags
& VM_MAYSHARE
) {
3736 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3745 if (unlikely(anon_vma_prepare(vma
))) {
3747 goto backout_unlocked
;
3753 * If memory error occurs between mmap() and fault, some process
3754 * don't have hwpoisoned swap entry for errored virtual address.
3755 * So we need to block hugepage fault by PG_hwpoison bit check.
3757 if (unlikely(PageHWPoison(page
))) {
3758 ret
= VM_FAULT_HWPOISON
|
3759 VM_FAULT_SET_HINDEX(hstate_index(h
));
3760 goto backout_unlocked
;
3765 * If we are going to COW a private mapping later, we examine the
3766 * pending reservations for this page now. This will ensure that
3767 * any allocations necessary to record that reservation occur outside
3770 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3771 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3773 goto backout_unlocked
;
3775 /* Just decrements count, does not deallocate */
3776 vma_end_reservation(h
, vma
, address
);
3779 ptl
= huge_pte_lock(h
, mm
, ptep
);
3780 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3785 if (!huge_pte_none(huge_ptep_get(ptep
)))
3789 ClearPagePrivate(page
);
3790 hugepage_add_new_anon_rmap(page
, vma
, address
);
3792 page_dup_rmap(page
, true);
3793 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
3794 && (vma
->vm_flags
& VM_SHARED
)));
3795 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
3797 hugetlb_count_add(pages_per_huge_page(h
), mm
);
3798 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3799 /* Optimization, do the COW without a second fault */
3800 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
3812 restore_reserve_on_error(h
, vma
, address
, page
);
3818 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3819 struct vm_area_struct
*vma
,
3820 struct address_space
*mapping
,
3821 pgoff_t idx
, unsigned long address
)
3823 unsigned long key
[2];
3826 if (vma
->vm_flags
& VM_SHARED
) {
3827 key
[0] = (unsigned long) mapping
;
3830 key
[0] = (unsigned long) mm
;
3831 key
[1] = address
>> huge_page_shift(h
);
3834 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
3836 return hash
& (num_fault_mutexes
- 1);
3840 * For uniprocesor systems we always use a single mutex, so just
3841 * return 0 and avoid the hashing overhead.
3843 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3844 struct vm_area_struct
*vma
,
3845 struct address_space
*mapping
,
3846 pgoff_t idx
, unsigned long address
)
3852 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3853 unsigned long address
, unsigned int flags
)
3860 struct page
*page
= NULL
;
3861 struct page
*pagecache_page
= NULL
;
3862 struct hstate
*h
= hstate_vma(vma
);
3863 struct address_space
*mapping
;
3864 int need_wait_lock
= 0;
3866 address
&= huge_page_mask(h
);
3868 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
3870 entry
= huge_ptep_get(ptep
);
3871 if (unlikely(is_hugetlb_entry_migration(entry
))) {
3872 migration_entry_wait_huge(vma
, mm
, ptep
);
3874 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
3875 return VM_FAULT_HWPOISON_LARGE
|
3876 VM_FAULT_SET_HINDEX(hstate_index(h
));
3878 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
3880 return VM_FAULT_OOM
;
3883 mapping
= vma
->vm_file
->f_mapping
;
3884 idx
= vma_hugecache_offset(h
, vma
, address
);
3887 * Serialize hugepage allocation and instantiation, so that we don't
3888 * get spurious allocation failures if two CPUs race to instantiate
3889 * the same page in the page cache.
3891 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
3892 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3894 entry
= huge_ptep_get(ptep
);
3895 if (huge_pte_none(entry
)) {
3896 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3903 * entry could be a migration/hwpoison entry at this point, so this
3904 * check prevents the kernel from going below assuming that we have
3905 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3906 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3909 if (!pte_present(entry
))
3913 * If we are going to COW the mapping later, we examine the pending
3914 * reservations for this page now. This will ensure that any
3915 * allocations necessary to record that reservation occur outside the
3916 * spinlock. For private mappings, we also lookup the pagecache
3917 * page now as it is used to determine if a reservation has been
3920 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3921 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3925 /* Just decrements count, does not deallocate */
3926 vma_end_reservation(h
, vma
, address
);
3928 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3929 pagecache_page
= hugetlbfs_pagecache_page(h
,
3933 ptl
= huge_pte_lock(h
, mm
, ptep
);
3935 /* Check for a racing update before calling hugetlb_cow */
3936 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3940 * hugetlb_cow() requires page locks of pte_page(entry) and
3941 * pagecache_page, so here we need take the former one
3942 * when page != pagecache_page or !pagecache_page.
3944 page
= pte_page(entry
);
3945 if (page
!= pagecache_page
)
3946 if (!trylock_page(page
)) {
3953 if (flags
& FAULT_FLAG_WRITE
) {
3954 if (!huge_pte_write(entry
)) {
3955 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
3956 pagecache_page
, ptl
);
3959 entry
= huge_pte_mkdirty(entry
);
3961 entry
= pte_mkyoung(entry
);
3962 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3963 flags
& FAULT_FLAG_WRITE
))
3964 update_mmu_cache(vma
, address
, ptep
);
3966 if (page
!= pagecache_page
)
3972 if (pagecache_page
) {
3973 unlock_page(pagecache_page
);
3974 put_page(pagecache_page
);
3977 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3979 * Generally it's safe to hold refcount during waiting page lock. But
3980 * here we just wait to defer the next page fault to avoid busy loop and
3981 * the page is not used after unlocked before returning from the current
3982 * page fault. So we are safe from accessing freed page, even if we wait
3983 * here without taking refcount.
3986 wait_on_page_locked(page
);
3991 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
3992 * modifications for huge pages.
3994 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
3996 struct vm_area_struct
*dst_vma
,
3997 unsigned long dst_addr
,
3998 unsigned long src_addr
,
3999 struct page
**pagep
)
4001 struct address_space
*mapping
;
4004 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4005 struct hstate
*h
= hstate_vma(dst_vma
);
4013 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4017 ret
= copy_huge_page_from_user(page
,
4018 (const void __user
*) src_addr
,
4019 pages_per_huge_page(h
), false);
4021 /* fallback to copy_from_user outside mmap_sem */
4022 if (unlikely(ret
)) {
4025 /* don't free the page */
4034 * The memory barrier inside __SetPageUptodate makes sure that
4035 * preceding stores to the page contents become visible before
4036 * the set_pte_at() write.
4038 __SetPageUptodate(page
);
4039 set_page_huge_active(page
);
4041 mapping
= dst_vma
->vm_file
->f_mapping
;
4042 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4045 * If shared, add to page cache
4048 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4051 goto out_release_nounlock
;
4054 * Serialization between remove_inode_hugepages() and
4055 * huge_add_to_page_cache() below happens through the
4056 * hugetlb_fault_mutex_table that here must be hold by
4059 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4061 goto out_release_nounlock
;
4064 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4068 * Recheck the i_size after holding PT lock to make sure not
4069 * to leave any page mapped (as page_mapped()) beyond the end
4070 * of the i_size (remove_inode_hugepages() is strict about
4071 * enforcing that). If we bail out here, we'll also leave a
4072 * page in the radix tree in the vm_shared case beyond the end
4073 * of the i_size, but remove_inode_hugepages() will take care
4074 * of it as soon as we drop the hugetlb_fault_mutex_table.
4076 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4079 goto out_release_unlock
;
4082 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4083 goto out_release_unlock
;
4086 page_dup_rmap(page
, true);
4088 ClearPagePrivate(page
);
4089 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4092 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4093 if (dst_vma
->vm_flags
& VM_WRITE
)
4094 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4095 _dst_pte
= pte_mkyoung(_dst_pte
);
4097 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4099 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4100 dst_vma
->vm_flags
& VM_WRITE
);
4101 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4103 /* No need to invalidate - it was non-present before */
4104 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4116 out_release_nounlock
:
4121 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4122 struct page
**pages
, struct vm_area_struct
**vmas
,
4123 unsigned long *position
, unsigned long *nr_pages
,
4124 long i
, unsigned int flags
, int *nonblocking
)
4126 unsigned long pfn_offset
;
4127 unsigned long vaddr
= *position
;
4128 unsigned long remainder
= *nr_pages
;
4129 struct hstate
*h
= hstate_vma(vma
);
4132 while (vaddr
< vma
->vm_end
&& remainder
) {
4134 spinlock_t
*ptl
= NULL
;
4139 * If we have a pending SIGKILL, don't keep faulting pages and
4140 * potentially allocating memory.
4142 if (unlikely(fatal_signal_pending(current
))) {
4148 * Some archs (sparc64, sh*) have multiple pte_ts to
4149 * each hugepage. We have to make sure we get the
4150 * first, for the page indexing below to work.
4152 * Note that page table lock is not held when pte is null.
4154 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4157 ptl
= huge_pte_lock(h
, mm
, pte
);
4158 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4161 * When coredumping, it suits get_dump_page if we just return
4162 * an error where there's an empty slot with no huge pagecache
4163 * to back it. This way, we avoid allocating a hugepage, and
4164 * the sparse dumpfile avoids allocating disk blocks, but its
4165 * huge holes still show up with zeroes where they need to be.
4167 if (absent
&& (flags
& FOLL_DUMP
) &&
4168 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4176 * We need call hugetlb_fault for both hugepages under migration
4177 * (in which case hugetlb_fault waits for the migration,) and
4178 * hwpoisoned hugepages (in which case we need to prevent the
4179 * caller from accessing to them.) In order to do this, we use
4180 * here is_swap_pte instead of is_hugetlb_entry_migration and
4181 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4182 * both cases, and because we can't follow correct pages
4183 * directly from any kind of swap entries.
4185 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4186 ((flags
& FOLL_WRITE
) &&
4187 !huge_pte_write(huge_ptep_get(pte
)))) {
4189 unsigned int fault_flags
= 0;
4193 if (flags
& FOLL_WRITE
)
4194 fault_flags
|= FAULT_FLAG_WRITE
;
4196 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
4197 if (flags
& FOLL_NOWAIT
)
4198 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4199 FAULT_FLAG_RETRY_NOWAIT
;
4200 if (flags
& FOLL_TRIED
) {
4201 VM_WARN_ON_ONCE(fault_flags
&
4202 FAULT_FLAG_ALLOW_RETRY
);
4203 fault_flags
|= FAULT_FLAG_TRIED
;
4205 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4206 if (ret
& VM_FAULT_ERROR
) {
4207 err
= vm_fault_to_errno(ret
, flags
);
4211 if (ret
& VM_FAULT_RETRY
) {
4216 * VM_FAULT_RETRY must not return an
4217 * error, it will return zero
4220 * No need to update "position" as the
4221 * caller will not check it after
4222 * *nr_pages is set to 0.
4229 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4230 page
= pte_page(huge_ptep_get(pte
));
4233 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4244 if (vaddr
< vma
->vm_end
&& remainder
&&
4245 pfn_offset
< pages_per_huge_page(h
)) {
4247 * We use pfn_offset to avoid touching the pageframes
4248 * of this compound page.
4254 *nr_pages
= remainder
;
4256 * setting position is actually required only if remainder is
4257 * not zero but it's faster not to add a "if (remainder)"
4265 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4267 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4270 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4273 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4274 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4276 struct mm_struct
*mm
= vma
->vm_mm
;
4277 unsigned long start
= address
;
4280 struct hstate
*h
= hstate_vma(vma
);
4281 unsigned long pages
= 0;
4283 BUG_ON(address
>= end
);
4284 flush_cache_range(vma
, address
, end
);
4286 mmu_notifier_invalidate_range_start(mm
, start
, end
);
4287 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4288 for (; address
< end
; address
+= huge_page_size(h
)) {
4290 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4293 ptl
= huge_pte_lock(h
, mm
, ptep
);
4294 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4299 pte
= huge_ptep_get(ptep
);
4300 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4304 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4305 swp_entry_t entry
= pte_to_swp_entry(pte
);
4307 if (is_write_migration_entry(entry
)) {
4310 make_migration_entry_read(&entry
);
4311 newpte
= swp_entry_to_pte(entry
);
4312 set_huge_swap_pte_at(mm
, address
, ptep
,
4313 newpte
, huge_page_size(h
));
4319 if (!huge_pte_none(pte
)) {
4320 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
4321 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
4322 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4323 set_huge_pte_at(mm
, address
, ptep
, pte
);
4329 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4330 * may have cleared our pud entry and done put_page on the page table:
4331 * once we release i_mmap_rwsem, another task can do the final put_page
4332 * and that page table be reused and filled with junk.
4334 flush_hugetlb_tlb_range(vma
, start
, end
);
4336 * No need to call mmu_notifier_invalidate_range() we are downgrading
4337 * page table protection not changing it to point to a new page.
4339 * See Documentation/vm/mmu_notifier.txt
4341 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4342 mmu_notifier_invalidate_range_end(mm
, start
, end
);
4344 return pages
<< h
->order
;
4347 int hugetlb_reserve_pages(struct inode
*inode
,
4349 struct vm_area_struct
*vma
,
4350 vm_flags_t vm_flags
)
4353 struct hstate
*h
= hstate_inode(inode
);
4354 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4355 struct resv_map
*resv_map
;
4358 /* This should never happen */
4360 VM_WARN(1, "%s called with a negative range\n", __func__
);
4365 * Only apply hugepage reservation if asked. At fault time, an
4366 * attempt will be made for VM_NORESERVE to allocate a page
4367 * without using reserves
4369 if (vm_flags
& VM_NORESERVE
)
4373 * Shared mappings base their reservation on the number of pages that
4374 * are already allocated on behalf of the file. Private mappings need
4375 * to reserve the full area even if read-only as mprotect() may be
4376 * called to make the mapping read-write. Assume !vma is a shm mapping
4378 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4379 resv_map
= inode_resv_map(inode
);
4381 chg
= region_chg(resv_map
, from
, to
);
4384 resv_map
= resv_map_alloc();
4390 set_vma_resv_map(vma
, resv_map
);
4391 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4400 * There must be enough pages in the subpool for the mapping. If
4401 * the subpool has a minimum size, there may be some global
4402 * reservations already in place (gbl_reserve).
4404 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4405 if (gbl_reserve
< 0) {
4411 * Check enough hugepages are available for the reservation.
4412 * Hand the pages back to the subpool if there are not
4414 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4416 /* put back original number of pages, chg */
4417 (void)hugepage_subpool_put_pages(spool
, chg
);
4422 * Account for the reservations made. Shared mappings record regions
4423 * that have reservations as they are shared by multiple VMAs.
4424 * When the last VMA disappears, the region map says how much
4425 * the reservation was and the page cache tells how much of
4426 * the reservation was consumed. Private mappings are per-VMA and
4427 * only the consumed reservations are tracked. When the VMA
4428 * disappears, the original reservation is the VMA size and the
4429 * consumed reservations are stored in the map. Hence, nothing
4430 * else has to be done for private mappings here
4432 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4433 long add
= region_add(resv_map
, from
, to
);
4435 if (unlikely(chg
> add
)) {
4437 * pages in this range were added to the reserve
4438 * map between region_chg and region_add. This
4439 * indicates a race with alloc_huge_page. Adjust
4440 * the subpool and reserve counts modified above
4441 * based on the difference.
4445 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4447 hugetlb_acct_memory(h
, -rsv_adjust
);
4452 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4453 /* Don't call region_abort if region_chg failed */
4455 region_abort(resv_map
, from
, to
);
4456 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4457 kref_put(&resv_map
->refs
, resv_map_release
);
4461 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4464 struct hstate
*h
= hstate_inode(inode
);
4465 struct resv_map
*resv_map
= inode_resv_map(inode
);
4467 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4471 chg
= region_del(resv_map
, start
, end
);
4473 * region_del() can fail in the rare case where a region
4474 * must be split and another region descriptor can not be
4475 * allocated. If end == LONG_MAX, it will not fail.
4481 spin_lock(&inode
->i_lock
);
4482 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4483 spin_unlock(&inode
->i_lock
);
4486 * If the subpool has a minimum size, the number of global
4487 * reservations to be released may be adjusted.
4489 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4490 hugetlb_acct_memory(h
, -gbl_reserve
);
4495 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4496 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4497 struct vm_area_struct
*vma
,
4498 unsigned long addr
, pgoff_t idx
)
4500 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4502 unsigned long sbase
= saddr
& PUD_MASK
;
4503 unsigned long s_end
= sbase
+ PUD_SIZE
;
4505 /* Allow segments to share if only one is marked locked */
4506 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4507 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4510 * match the virtual addresses, permission and the alignment of the
4513 if (pmd_index(addr
) != pmd_index(saddr
) ||
4514 vm_flags
!= svm_flags
||
4515 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4521 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4523 unsigned long base
= addr
& PUD_MASK
;
4524 unsigned long end
= base
+ PUD_SIZE
;
4527 * check on proper vm_flags and page table alignment
4529 if (vma
->vm_flags
& VM_MAYSHARE
&&
4530 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
4536 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4537 * and returns the corresponding pte. While this is not necessary for the
4538 * !shared pmd case because we can allocate the pmd later as well, it makes the
4539 * code much cleaner. pmd allocation is essential for the shared case because
4540 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4541 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4542 * bad pmd for sharing.
4544 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4546 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4547 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4548 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4550 struct vm_area_struct
*svma
;
4551 unsigned long saddr
;
4556 if (!vma_shareable(vma
, addr
))
4557 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4559 i_mmap_lock_write(mapping
);
4560 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4564 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4566 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
4567 vma_mmu_pagesize(svma
));
4569 get_page(virt_to_page(spte
));
4578 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
4579 if (pud_none(*pud
)) {
4580 pud_populate(mm
, pud
,
4581 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4584 put_page(virt_to_page(spte
));
4588 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4589 i_mmap_unlock_write(mapping
);
4594 * unmap huge page backed by shared pte.
4596 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4597 * indicated by page_count > 1, unmap is achieved by clearing pud and
4598 * decrementing the ref count. If count == 1, the pte page is not shared.
4600 * called with page table lock held.
4602 * returns: 1 successfully unmapped a shared pte page
4603 * 0 the underlying pte page is not shared, or it is the last user
4605 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4607 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4608 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
4609 pud_t
*pud
= pud_offset(p4d
, *addr
);
4611 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4612 if (page_count(virt_to_page(ptep
)) == 1)
4616 put_page(virt_to_page(ptep
));
4618 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4621 #define want_pmd_share() (1)
4622 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4623 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4628 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4632 #define want_pmd_share() (0)
4633 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4635 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4636 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4637 unsigned long addr
, unsigned long sz
)
4644 pgd
= pgd_offset(mm
, addr
);
4645 p4d
= p4d_alloc(mm
, pgd
, addr
);
4648 pud
= pud_alloc(mm
, p4d
, addr
);
4650 if (sz
== PUD_SIZE
) {
4653 BUG_ON(sz
!= PMD_SIZE
);
4654 if (want_pmd_share() && pud_none(*pud
))
4655 pte
= huge_pmd_share(mm
, addr
, pud
);
4657 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4660 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
4666 * huge_pte_offset() - Walk the page table to resolve the hugepage
4667 * entry at address @addr
4669 * Return: Pointer to page table or swap entry (PUD or PMD) for
4670 * address @addr, or NULL if a p*d_none() entry is encountered and the
4671 * size @sz doesn't match the hugepage size at this level of the page
4674 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
4675 unsigned long addr
, unsigned long sz
)
4682 pgd
= pgd_offset(mm
, addr
);
4683 if (!pgd_present(*pgd
))
4685 p4d
= p4d_offset(pgd
, addr
);
4686 if (!p4d_present(*p4d
))
4689 pud
= pud_offset(p4d
, addr
);
4690 if (sz
!= PUD_SIZE
&& pud_none(*pud
))
4692 /* hugepage or swap? */
4693 if (pud_huge(*pud
) || !pud_present(*pud
))
4694 return (pte_t
*)pud
;
4696 pmd
= pmd_offset(pud
, addr
);
4697 if (sz
!= PMD_SIZE
&& pmd_none(*pmd
))
4699 /* hugepage or swap? */
4700 if (pmd_huge(*pmd
) || !pmd_present(*pmd
))
4701 return (pte_t
*)pmd
;
4706 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4709 * These functions are overwritable if your architecture needs its own
4712 struct page
* __weak
4713 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
4716 return ERR_PTR(-EINVAL
);
4719 struct page
* __weak
4720 follow_huge_pd(struct vm_area_struct
*vma
,
4721 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
4723 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
4727 struct page
* __weak
4728 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
4729 pmd_t
*pmd
, int flags
)
4731 struct page
*page
= NULL
;
4735 ptl
= pmd_lockptr(mm
, pmd
);
4738 * make sure that the address range covered by this pmd is not
4739 * unmapped from other threads.
4741 if (!pmd_huge(*pmd
))
4743 pte
= huge_ptep_get((pte_t
*)pmd
);
4744 if (pte_present(pte
)) {
4745 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
4746 if (flags
& FOLL_GET
)
4749 if (is_hugetlb_entry_migration(pte
)) {
4751 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
4755 * hwpoisoned entry is treated as no_page_table in
4756 * follow_page_mask().
4764 struct page
* __weak
4765 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
4766 pud_t
*pud
, int flags
)
4768 if (flags
& FOLL_GET
)
4771 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
4774 struct page
* __weak
4775 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
4777 if (flags
& FOLL_GET
)
4780 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
4783 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
4787 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4788 spin_lock(&hugetlb_lock
);
4789 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
4793 clear_page_huge_active(page
);
4794 list_move_tail(&page
->lru
, list
);
4796 spin_unlock(&hugetlb_lock
);
4800 void putback_active_hugepage(struct page
*page
)
4802 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4803 spin_lock(&hugetlb_lock
);
4804 set_page_huge_active(page
);
4805 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
4806 spin_unlock(&hugetlb_lock
);