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/rmap.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
24 #include <linux/page-isolation.h>
25 #include <linux/jhash.h>
28 #include <asm/pgtable.h>
32 #include <linux/hugetlb.h>
33 #include <linux/hugetlb_cgroup.h>
34 #include <linux/node.h>
37 int hugepages_treat_as_movable
;
39 int hugetlb_max_hstate __read_mostly
;
40 unsigned int default_hstate_idx
;
41 struct hstate hstates
[HUGE_MAX_HSTATE
];
43 * Minimum page order among possible hugepage sizes, set to a proper value
46 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
48 __initdata
LIST_HEAD(huge_boot_pages
);
50 /* for command line parsing */
51 static struct hstate
* __initdata parsed_hstate
;
52 static unsigned long __initdata default_hstate_max_huge_pages
;
53 static unsigned long __initdata default_hstate_size
;
54 static bool __initdata parsed_valid_hugepagesz
= true;
57 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
58 * free_huge_pages, and surplus_huge_pages.
60 DEFINE_SPINLOCK(hugetlb_lock
);
63 * Serializes faults on the same logical page. This is used to
64 * prevent spurious OOMs when the hugepage pool is fully utilized.
66 static int num_fault_mutexes
;
67 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
69 /* Forward declaration */
70 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
72 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
74 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
76 spin_unlock(&spool
->lock
);
78 /* If no pages are used, and no other handles to the subpool
79 * remain, give up any reservations mased on minimum size and
82 if (spool
->min_hpages
!= -1)
83 hugetlb_acct_memory(spool
->hstate
,
89 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
92 struct hugepage_subpool
*spool
;
94 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
98 spin_lock_init(&spool
->lock
);
100 spool
->max_hpages
= max_hpages
;
102 spool
->min_hpages
= min_hpages
;
104 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
108 spool
->rsv_hpages
= min_hpages
;
113 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
115 spin_lock(&spool
->lock
);
116 BUG_ON(!spool
->count
);
118 unlock_or_release_subpool(spool
);
122 * Subpool accounting for allocating and reserving pages.
123 * Return -ENOMEM if there are not enough resources to satisfy the
124 * the request. Otherwise, return the number of pages by which the
125 * global pools must be adjusted (upward). The returned value may
126 * only be different than the passed value (delta) in the case where
127 * a subpool minimum size must be manitained.
129 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
137 spin_lock(&spool
->lock
);
139 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
140 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
141 spool
->used_hpages
+= delta
;
148 /* minimum size accounting */
149 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
150 if (delta
> spool
->rsv_hpages
) {
152 * Asking for more reserves than those already taken on
153 * behalf of subpool. Return difference.
155 ret
= delta
- spool
->rsv_hpages
;
156 spool
->rsv_hpages
= 0;
158 ret
= 0; /* reserves already accounted for */
159 spool
->rsv_hpages
-= delta
;
164 spin_unlock(&spool
->lock
);
169 * Subpool accounting for freeing and unreserving pages.
170 * Return the number of global page reservations that must be dropped.
171 * The return value may only be different than the passed value (delta)
172 * in the case where a subpool minimum size must be maintained.
174 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
182 spin_lock(&spool
->lock
);
184 if (spool
->max_hpages
!= -1) /* maximum size accounting */
185 spool
->used_hpages
-= delta
;
187 /* minimum size accounting */
188 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
189 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
192 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
194 spool
->rsv_hpages
+= delta
;
195 if (spool
->rsv_hpages
> spool
->min_hpages
)
196 spool
->rsv_hpages
= spool
->min_hpages
;
200 * If hugetlbfs_put_super couldn't free spool due to an outstanding
201 * quota reference, free it now.
203 unlock_or_release_subpool(spool
);
208 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
210 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
213 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
215 return subpool_inode(file_inode(vma
->vm_file
));
219 * Region tracking -- allows tracking of reservations and instantiated pages
220 * across the pages in a mapping.
222 * The region data structures are embedded into a resv_map and protected
223 * by a resv_map's lock. The set of regions within the resv_map represent
224 * reservations for huge pages, or huge pages that have already been
225 * instantiated within the map. The from and to elements are huge page
226 * indicies into the associated mapping. from indicates the starting index
227 * of the region. to represents the first index past the end of the region.
229 * For example, a file region structure with from == 0 and to == 4 represents
230 * four huge pages in a mapping. It is important to note that the to element
231 * represents the first element past the end of the region. This is used in
232 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
234 * Interval notation of the form [from, to) will be used to indicate that
235 * the endpoint from is inclusive and to is exclusive.
238 struct list_head link
;
244 * Add the huge page range represented by [f, t) to the reserve
245 * map. In the normal case, existing regions will be expanded
246 * to accommodate the specified range. Sufficient regions should
247 * exist for expansion due to the previous call to region_chg
248 * with the same range. However, it is possible that region_del
249 * could have been called after region_chg and modifed the map
250 * in such a way that no region exists to be expanded. In this
251 * case, pull a region descriptor from the cache associated with
252 * the map and use that for the new range.
254 * Return the number of new huge pages added to the map. This
255 * number is greater than or equal to zero.
257 static long region_add(struct resv_map
*resv
, long f
, long t
)
259 struct list_head
*head
= &resv
->regions
;
260 struct file_region
*rg
, *nrg
, *trg
;
263 spin_lock(&resv
->lock
);
264 /* Locate the region we are either in or before. */
265 list_for_each_entry(rg
, head
, link
)
270 * If no region exists which can be expanded to include the
271 * specified range, the list must have been modified by an
272 * interleving call to region_del(). Pull a region descriptor
273 * from the cache and use it for this range.
275 if (&rg
->link
== head
|| t
< rg
->from
) {
276 VM_BUG_ON(resv
->region_cache_count
<= 0);
278 resv
->region_cache_count
--;
279 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
281 list_del(&nrg
->link
);
285 list_add(&nrg
->link
, rg
->link
.prev
);
291 /* Round our left edge to the current segment if it encloses us. */
295 /* Check for and consume any regions we now overlap with. */
297 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
298 if (&rg
->link
== head
)
303 /* If this area reaches higher then extend our area to
304 * include it completely. If this is not the first area
305 * which we intend to reuse, free it. */
309 /* Decrement return value by the deleted range.
310 * Another range will span this area so that by
311 * end of routine add will be >= zero
313 add
-= (rg
->to
- rg
->from
);
319 add
+= (nrg
->from
- f
); /* Added to beginning of region */
321 add
+= t
- nrg
->to
; /* Added to end of region */
325 resv
->adds_in_progress
--;
326 spin_unlock(&resv
->lock
);
332 * Examine the existing reserve map and determine how many
333 * huge pages in the specified range [f, t) are NOT currently
334 * represented. This routine is called before a subsequent
335 * call to region_add that will actually modify the reserve
336 * map to add the specified range [f, t). region_chg does
337 * not change the number of huge pages represented by the
338 * map. However, if the existing regions in the map can not
339 * be expanded to represent the new range, a new file_region
340 * structure is added to the map as a placeholder. This is
341 * so that the subsequent region_add call will have all the
342 * regions it needs and will not fail.
344 * Upon entry, region_chg will also examine the cache of region descriptors
345 * associated with the map. If there are not enough descriptors cached, one
346 * will be allocated for the in progress add operation.
348 * Returns the number of huge pages that need to be added to the existing
349 * reservation map for the range [f, t). This number is greater or equal to
350 * zero. -ENOMEM is returned if a new file_region structure or cache entry
351 * is needed and can not be allocated.
353 static long region_chg(struct resv_map
*resv
, long f
, long t
)
355 struct list_head
*head
= &resv
->regions
;
356 struct file_region
*rg
, *nrg
= NULL
;
360 spin_lock(&resv
->lock
);
362 resv
->adds_in_progress
++;
365 * Check for sufficient descriptors in the cache to accommodate
366 * the number of in progress add operations.
368 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
369 struct file_region
*trg
;
371 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
372 /* Must drop lock to allocate a new descriptor. */
373 resv
->adds_in_progress
--;
374 spin_unlock(&resv
->lock
);
376 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
382 spin_lock(&resv
->lock
);
383 list_add(&trg
->link
, &resv
->region_cache
);
384 resv
->region_cache_count
++;
388 /* Locate the region we are before or in. */
389 list_for_each_entry(rg
, head
, link
)
393 /* If we are below the current region then a new region is required.
394 * Subtle, allocate a new region at the position but make it zero
395 * size such that we can guarantee to record the reservation. */
396 if (&rg
->link
== head
|| t
< rg
->from
) {
398 resv
->adds_in_progress
--;
399 spin_unlock(&resv
->lock
);
400 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
406 INIT_LIST_HEAD(&nrg
->link
);
410 list_add(&nrg
->link
, rg
->link
.prev
);
415 /* Round our left edge to the current segment if it encloses us. */
420 /* Check for and consume any regions we now overlap with. */
421 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
422 if (&rg
->link
== head
)
427 /* We overlap with this area, if it extends further than
428 * us then we must extend ourselves. Account for its
429 * existing reservation. */
434 chg
-= rg
->to
- rg
->from
;
438 spin_unlock(&resv
->lock
);
439 /* We already know we raced and no longer need the new region */
443 spin_unlock(&resv
->lock
);
448 * Abort the in progress add operation. The adds_in_progress field
449 * of the resv_map keeps track of the operations in progress between
450 * calls to region_chg and region_add. Operations are sometimes
451 * aborted after the call to region_chg. In such cases, region_abort
452 * is called to decrement the adds_in_progress counter.
454 * NOTE: The range arguments [f, t) are not needed or used in this
455 * routine. They are kept to make reading the calling code easier as
456 * arguments will match the associated region_chg call.
458 static void region_abort(struct resv_map
*resv
, long f
, long t
)
460 spin_lock(&resv
->lock
);
461 VM_BUG_ON(!resv
->region_cache_count
);
462 resv
->adds_in_progress
--;
463 spin_unlock(&resv
->lock
);
467 * Delete the specified range [f, t) from the reserve map. If the
468 * t parameter is LONG_MAX, this indicates that ALL regions after f
469 * should be deleted. Locate the regions which intersect [f, t)
470 * and either trim, delete or split the existing regions.
472 * Returns the number of huge pages deleted from the reserve map.
473 * In the normal case, the return value is zero or more. In the
474 * case where a region must be split, a new region descriptor must
475 * be allocated. If the allocation fails, -ENOMEM will be returned.
476 * NOTE: If the parameter t == LONG_MAX, then we will never split
477 * a region and possibly return -ENOMEM. Callers specifying
478 * t == LONG_MAX do not need to check for -ENOMEM error.
480 static long region_del(struct resv_map
*resv
, long f
, long t
)
482 struct list_head
*head
= &resv
->regions
;
483 struct file_region
*rg
, *trg
;
484 struct file_region
*nrg
= NULL
;
488 spin_lock(&resv
->lock
);
489 list_for_each_entry_safe(rg
, trg
, head
, link
) {
491 * Skip regions before the range to be deleted. file_region
492 * ranges are normally of the form [from, to). However, there
493 * may be a "placeholder" entry in the map which is of the form
494 * (from, to) with from == to. Check for placeholder entries
495 * at the beginning of the range to be deleted.
497 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
503 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
505 * Check for an entry in the cache before dropping
506 * lock and attempting allocation.
509 resv
->region_cache_count
> resv
->adds_in_progress
) {
510 nrg
= list_first_entry(&resv
->region_cache
,
513 list_del(&nrg
->link
);
514 resv
->region_cache_count
--;
518 spin_unlock(&resv
->lock
);
519 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
527 /* New entry for end of split region */
530 INIT_LIST_HEAD(&nrg
->link
);
532 /* Original entry is trimmed */
535 list_add(&nrg
->link
, &rg
->link
);
540 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
541 del
+= rg
->to
- rg
->from
;
547 if (f
<= rg
->from
) { /* Trim beginning of region */
550 } else { /* Trim end of region */
556 spin_unlock(&resv
->lock
);
562 * A rare out of memory error was encountered which prevented removal of
563 * the reserve map region for a page. The huge page itself was free'ed
564 * and removed from the page cache. This routine will adjust the subpool
565 * usage count, and the global reserve count if needed. By incrementing
566 * these counts, the reserve map entry which could not be deleted will
567 * appear as a "reserved" entry instead of simply dangling with incorrect
570 void hugetlb_fix_reserve_counts(struct inode
*inode
, bool restore_reserve
)
572 struct hugepage_subpool
*spool
= subpool_inode(inode
);
575 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
576 if (restore_reserve
&& rsv_adjust
) {
577 struct hstate
*h
= hstate_inode(inode
);
579 hugetlb_acct_memory(h
, 1);
584 * Count and return the number of huge pages in the reserve map
585 * that intersect with the range [f, t).
587 static long region_count(struct resv_map
*resv
, long f
, long t
)
589 struct list_head
*head
= &resv
->regions
;
590 struct file_region
*rg
;
593 spin_lock(&resv
->lock
);
594 /* Locate each segment we overlap with, and count that overlap. */
595 list_for_each_entry(rg
, head
, link
) {
604 seg_from
= max(rg
->from
, f
);
605 seg_to
= min(rg
->to
, t
);
607 chg
+= seg_to
- seg_from
;
609 spin_unlock(&resv
->lock
);
615 * Convert the address within this vma to the page offset within
616 * the mapping, in pagecache page units; huge pages here.
618 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
619 struct vm_area_struct
*vma
, unsigned long address
)
621 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
622 (vma
->vm_pgoff
>> huge_page_order(h
));
625 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
626 unsigned long address
)
628 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
632 * Return the size of the pages allocated when backing a VMA. In the majority
633 * cases this will be same size as used by the page table entries.
635 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
637 struct hstate
*hstate
;
639 if (!is_vm_hugetlb_page(vma
))
642 hstate
= hstate_vma(vma
);
644 return 1UL << huge_page_shift(hstate
);
646 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
649 * Return the page size being used by the MMU to back a VMA. In the majority
650 * of cases, the page size used by the kernel matches the MMU size. On
651 * architectures where it differs, an architecture-specific version of this
652 * function is required.
654 #ifndef vma_mmu_pagesize
655 unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
657 return vma_kernel_pagesize(vma
);
662 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
663 * bits of the reservation map pointer, which are always clear due to
666 #define HPAGE_RESV_OWNER (1UL << 0)
667 #define HPAGE_RESV_UNMAPPED (1UL << 1)
668 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
671 * These helpers are used to track how many pages are reserved for
672 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
673 * is guaranteed to have their future faults succeed.
675 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
676 * the reserve counters are updated with the hugetlb_lock held. It is safe
677 * to reset the VMA at fork() time as it is not in use yet and there is no
678 * chance of the global counters getting corrupted as a result of the values.
680 * The private mapping reservation is represented in a subtly different
681 * manner to a shared mapping. A shared mapping has a region map associated
682 * with the underlying file, this region map represents the backing file
683 * pages which have ever had a reservation assigned which this persists even
684 * after the page is instantiated. A private mapping has a region map
685 * associated with the original mmap which is attached to all VMAs which
686 * reference it, this region map represents those offsets which have consumed
687 * reservation ie. where pages have been instantiated.
689 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
691 return (unsigned long)vma
->vm_private_data
;
694 static void set_vma_private_data(struct vm_area_struct
*vma
,
697 vma
->vm_private_data
= (void *)value
;
700 struct resv_map
*resv_map_alloc(void)
702 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
703 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
705 if (!resv_map
|| !rg
) {
711 kref_init(&resv_map
->refs
);
712 spin_lock_init(&resv_map
->lock
);
713 INIT_LIST_HEAD(&resv_map
->regions
);
715 resv_map
->adds_in_progress
= 0;
717 INIT_LIST_HEAD(&resv_map
->region_cache
);
718 list_add(&rg
->link
, &resv_map
->region_cache
);
719 resv_map
->region_cache_count
= 1;
724 void resv_map_release(struct kref
*ref
)
726 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
727 struct list_head
*head
= &resv_map
->region_cache
;
728 struct file_region
*rg
, *trg
;
730 /* Clear out any active regions before we release the map. */
731 region_del(resv_map
, 0, LONG_MAX
);
733 /* ... and any entries left in the cache */
734 list_for_each_entry_safe(rg
, trg
, head
, link
) {
739 VM_BUG_ON(resv_map
->adds_in_progress
);
744 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
746 return inode
->i_mapping
->private_data
;
749 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
751 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
752 if (vma
->vm_flags
& VM_MAYSHARE
) {
753 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
754 struct inode
*inode
= mapping
->host
;
756 return inode_resv_map(inode
);
759 return (struct resv_map
*)(get_vma_private_data(vma
) &
764 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
766 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
767 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
769 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
770 HPAGE_RESV_MASK
) | (unsigned long)map
);
773 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
775 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
776 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
778 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
781 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
783 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
785 return (get_vma_private_data(vma
) & flag
) != 0;
788 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
789 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
791 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
792 if (!(vma
->vm_flags
& VM_MAYSHARE
))
793 vma
->vm_private_data
= (void *)0;
796 /* Returns true if the VMA has associated reserve pages */
797 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
799 if (vma
->vm_flags
& VM_NORESERVE
) {
801 * This address is already reserved by other process(chg == 0),
802 * so, we should decrement reserved count. Without decrementing,
803 * reserve count remains after releasing inode, because this
804 * allocated page will go into page cache and is regarded as
805 * coming from reserved pool in releasing step. Currently, we
806 * don't have any other solution to deal with this situation
807 * properly, so add work-around here.
809 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
815 /* Shared mappings always use reserves */
816 if (vma
->vm_flags
& VM_MAYSHARE
) {
818 * We know VM_NORESERVE is not set. Therefore, there SHOULD
819 * be a region map for all pages. The only situation where
820 * there is no region map is if a hole was punched via
821 * fallocate. In this case, there really are no reverves to
822 * use. This situation is indicated if chg != 0.
831 * Only the process that called mmap() has reserves for
834 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
840 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
842 int nid
= page_to_nid(page
);
843 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
844 h
->free_huge_pages
++;
845 h
->free_huge_pages_node
[nid
]++;
848 static struct page
*dequeue_huge_page_node(struct hstate
*h
, int nid
)
852 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
853 if (!is_migrate_isolate_page(page
))
856 * if 'non-isolated free hugepage' not found on the list,
857 * the allocation fails.
859 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
861 list_move(&page
->lru
, &h
->hugepage_activelist
);
862 set_page_refcounted(page
);
863 h
->free_huge_pages
--;
864 h
->free_huge_pages_node
[nid
]--;
868 /* Movability of hugepages depends on migration support. */
869 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
871 if (hugepages_treat_as_movable
|| hugepage_migration_supported(h
))
872 return GFP_HIGHUSER_MOVABLE
;
877 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
878 struct vm_area_struct
*vma
,
879 unsigned long address
, int avoid_reserve
,
882 struct page
*page
= NULL
;
883 struct mempolicy
*mpol
;
884 nodemask_t
*nodemask
;
885 struct zonelist
*zonelist
;
888 unsigned int cpuset_mems_cookie
;
891 * A child process with MAP_PRIVATE mappings created by their parent
892 * have no page reserves. This check ensures that reservations are
893 * not "stolen". The child may still get SIGKILLed
895 if (!vma_has_reserves(vma
, chg
) &&
896 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
899 /* If reserves cannot be used, ensure enough pages are in the pool */
900 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
904 cpuset_mems_cookie
= read_mems_allowed_begin();
905 zonelist
= huge_zonelist(vma
, address
,
906 htlb_alloc_mask(h
), &mpol
, &nodemask
);
908 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
,
909 MAX_NR_ZONES
- 1, nodemask
) {
910 if (cpuset_zone_allowed(zone
, htlb_alloc_mask(h
))) {
911 page
= dequeue_huge_page_node(h
, zone_to_nid(zone
));
915 if (!vma_has_reserves(vma
, chg
))
918 SetPagePrivate(page
);
919 h
->resv_huge_pages
--;
926 if (unlikely(!page
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
935 * common helper functions for hstate_next_node_to_{alloc|free}.
936 * We may have allocated or freed a huge page based on a different
937 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
938 * be outside of *nodes_allowed. Ensure that we use an allowed
939 * node for alloc or free.
941 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
943 nid
= next_node_in(nid
, *nodes_allowed
);
944 VM_BUG_ON(nid
>= MAX_NUMNODES
);
949 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
951 if (!node_isset(nid
, *nodes_allowed
))
952 nid
= next_node_allowed(nid
, nodes_allowed
);
957 * returns the previously saved node ["this node"] from which to
958 * allocate a persistent huge page for the pool and advance the
959 * next node from which to allocate, handling wrap at end of node
962 static int hstate_next_node_to_alloc(struct hstate
*h
,
963 nodemask_t
*nodes_allowed
)
967 VM_BUG_ON(!nodes_allowed
);
969 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
970 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
976 * helper for free_pool_huge_page() - return the previously saved
977 * node ["this node"] from which to free a huge page. Advance the
978 * next node id whether or not we find a free huge page to free so
979 * that the next attempt to free addresses the next node.
981 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
985 VM_BUG_ON(!nodes_allowed
);
987 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
988 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
993 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
994 for (nr_nodes = nodes_weight(*mask); \
996 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
999 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1000 for (nr_nodes = nodes_weight(*mask); \
1002 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1005 #if defined(CONFIG_X86_64) && ((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA))
1006 static void destroy_compound_gigantic_page(struct page
*page
,
1010 int nr_pages
= 1 << order
;
1011 struct page
*p
= page
+ 1;
1013 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1014 clear_compound_head(p
);
1015 set_page_refcounted(p
);
1018 set_compound_order(page
, 0);
1019 __ClearPageHead(page
);
1022 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1024 free_contig_range(page_to_pfn(page
), 1 << order
);
1027 static int __alloc_gigantic_page(unsigned long start_pfn
,
1028 unsigned long nr_pages
)
1030 unsigned long end_pfn
= start_pfn
+ nr_pages
;
1031 return alloc_contig_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
);
1034 static bool pfn_range_valid_gigantic(struct zone
*z
,
1035 unsigned long start_pfn
, unsigned long nr_pages
)
1037 unsigned long i
, end_pfn
= start_pfn
+ nr_pages
;
1040 for (i
= start_pfn
; i
< end_pfn
; i
++) {
1044 page
= pfn_to_page(i
);
1046 if (page_zone(page
) != z
)
1049 if (PageReserved(page
))
1052 if (page_count(page
) > 0)
1062 static bool zone_spans_last_pfn(const struct zone
*zone
,
1063 unsigned long start_pfn
, unsigned long nr_pages
)
1065 unsigned long last_pfn
= start_pfn
+ nr_pages
- 1;
1066 return zone_spans_pfn(zone
, last_pfn
);
1069 static struct page
*alloc_gigantic_page(int nid
, unsigned int order
)
1071 unsigned long nr_pages
= 1 << order
;
1072 unsigned long ret
, pfn
, flags
;
1075 z
= NODE_DATA(nid
)->node_zones
;
1076 for (; z
- NODE_DATA(nid
)->node_zones
< MAX_NR_ZONES
; z
++) {
1077 spin_lock_irqsave(&z
->lock
, flags
);
1079 pfn
= ALIGN(z
->zone_start_pfn
, nr_pages
);
1080 while (zone_spans_last_pfn(z
, pfn
, nr_pages
)) {
1081 if (pfn_range_valid_gigantic(z
, pfn
, nr_pages
)) {
1083 * We release the zone lock here because
1084 * alloc_contig_range() will also lock the zone
1085 * at some point. If there's an allocation
1086 * spinning on this lock, it may win the race
1087 * and cause alloc_contig_range() to fail...
1089 spin_unlock_irqrestore(&z
->lock
, flags
);
1090 ret
= __alloc_gigantic_page(pfn
, nr_pages
);
1092 return pfn_to_page(pfn
);
1093 spin_lock_irqsave(&z
->lock
, flags
);
1098 spin_unlock_irqrestore(&z
->lock
, flags
);
1104 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1105 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1107 static struct page
*alloc_fresh_gigantic_page_node(struct hstate
*h
, int nid
)
1111 page
= alloc_gigantic_page(nid
, huge_page_order(h
));
1113 prep_compound_gigantic_page(page
, huge_page_order(h
));
1114 prep_new_huge_page(h
, page
, nid
);
1120 static int alloc_fresh_gigantic_page(struct hstate
*h
,
1121 nodemask_t
*nodes_allowed
)
1123 struct page
*page
= NULL
;
1126 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1127 page
= alloc_fresh_gigantic_page_node(h
, node
);
1135 static inline bool gigantic_page_supported(void) { return true; }
1137 static inline bool gigantic_page_supported(void) { return false; }
1138 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1139 static inline void destroy_compound_gigantic_page(struct page
*page
,
1140 unsigned int order
) { }
1141 static inline int alloc_fresh_gigantic_page(struct hstate
*h
,
1142 nodemask_t
*nodes_allowed
) { return 0; }
1145 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1149 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
1153 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1154 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1155 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1156 1 << PG_referenced
| 1 << PG_dirty
|
1157 1 << PG_active
| 1 << PG_private
|
1160 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1161 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1162 set_page_refcounted(page
);
1163 if (hstate_is_gigantic(h
)) {
1164 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1165 free_gigantic_page(page
, huge_page_order(h
));
1167 __free_pages(page
, huge_page_order(h
));
1171 struct hstate
*size_to_hstate(unsigned long size
)
1175 for_each_hstate(h
) {
1176 if (huge_page_size(h
) == size
)
1183 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1184 * to hstate->hugepage_activelist.)
1186 * This function can be called for tail pages, but never returns true for them.
1188 bool page_huge_active(struct page
*page
)
1190 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1191 return PageHead(page
) && PagePrivate(&page
[1]);
1194 /* never called for tail page */
1195 static void set_page_huge_active(struct page
*page
)
1197 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1198 SetPagePrivate(&page
[1]);
1201 static void clear_page_huge_active(struct page
*page
)
1203 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1204 ClearPagePrivate(&page
[1]);
1207 void free_huge_page(struct page
*page
)
1210 * Can't pass hstate in here because it is called from the
1211 * compound page destructor.
1213 struct hstate
*h
= page_hstate(page
);
1214 int nid
= page_to_nid(page
);
1215 struct hugepage_subpool
*spool
=
1216 (struct hugepage_subpool
*)page_private(page
);
1217 bool restore_reserve
;
1219 set_page_private(page
, 0);
1220 page
->mapping
= NULL
;
1221 VM_BUG_ON_PAGE(page_count(page
), page
);
1222 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1223 restore_reserve
= PagePrivate(page
);
1224 ClearPagePrivate(page
);
1227 * A return code of zero implies that the subpool will be under its
1228 * minimum size if the reservation is not restored after page is free.
1229 * Therefore, force restore_reserve operation.
1231 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1232 restore_reserve
= true;
1234 spin_lock(&hugetlb_lock
);
1235 clear_page_huge_active(page
);
1236 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1237 pages_per_huge_page(h
), page
);
1238 if (restore_reserve
)
1239 h
->resv_huge_pages
++;
1241 if (h
->surplus_huge_pages_node
[nid
]) {
1242 /* remove the page from active list */
1243 list_del(&page
->lru
);
1244 update_and_free_page(h
, page
);
1245 h
->surplus_huge_pages
--;
1246 h
->surplus_huge_pages_node
[nid
]--;
1248 arch_clear_hugepage_flags(page
);
1249 enqueue_huge_page(h
, page
);
1251 spin_unlock(&hugetlb_lock
);
1254 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1256 INIT_LIST_HEAD(&page
->lru
);
1257 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1258 spin_lock(&hugetlb_lock
);
1259 set_hugetlb_cgroup(page
, NULL
);
1261 h
->nr_huge_pages_node
[nid
]++;
1262 spin_unlock(&hugetlb_lock
);
1263 put_page(page
); /* free it into the hugepage allocator */
1266 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1269 int nr_pages
= 1 << order
;
1270 struct page
*p
= page
+ 1;
1272 /* we rely on prep_new_huge_page to set the destructor */
1273 set_compound_order(page
, order
);
1274 __ClearPageReserved(page
);
1275 __SetPageHead(page
);
1276 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1278 * For gigantic hugepages allocated through bootmem at
1279 * boot, it's safer to be consistent with the not-gigantic
1280 * hugepages and clear the PG_reserved bit from all tail pages
1281 * too. Otherwse drivers using get_user_pages() to access tail
1282 * pages may get the reference counting wrong if they see
1283 * PG_reserved set on a tail page (despite the head page not
1284 * having PG_reserved set). Enforcing this consistency between
1285 * head and tail pages allows drivers to optimize away a check
1286 * on the head page when they need know if put_page() is needed
1287 * after get_user_pages().
1289 __ClearPageReserved(p
);
1290 set_page_count(p
, 0);
1291 set_compound_head(p
, page
);
1293 atomic_set(compound_mapcount_ptr(page
), -1);
1297 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1298 * transparent huge pages. See the PageTransHuge() documentation for more
1301 int PageHuge(struct page
*page
)
1303 if (!PageCompound(page
))
1306 page
= compound_head(page
);
1307 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1309 EXPORT_SYMBOL_GPL(PageHuge
);
1312 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1313 * normal or transparent huge pages.
1315 int PageHeadHuge(struct page
*page_head
)
1317 if (!PageHead(page_head
))
1320 return get_compound_page_dtor(page_head
) == free_huge_page
;
1323 pgoff_t
__basepage_index(struct page
*page
)
1325 struct page
*page_head
= compound_head(page
);
1326 pgoff_t index
= page_index(page_head
);
1327 unsigned long compound_idx
;
1329 if (!PageHuge(page_head
))
1330 return page_index(page
);
1332 if (compound_order(page_head
) >= MAX_ORDER
)
1333 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1335 compound_idx
= page
- page_head
;
1337 return (index
<< compound_order(page_head
)) + compound_idx
;
1340 static struct page
*alloc_fresh_huge_page_node(struct hstate
*h
, int nid
)
1344 page
= __alloc_pages_node(nid
,
1345 htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_THISNODE
|
1346 __GFP_REPEAT
|__GFP_NOWARN
,
1347 huge_page_order(h
));
1349 prep_new_huge_page(h
, page
, nid
);
1355 static int alloc_fresh_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1361 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1362 page
= alloc_fresh_huge_page_node(h
, node
);
1370 count_vm_event(HTLB_BUDDY_PGALLOC
);
1372 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1378 * Free huge page from pool from next node to free.
1379 * Attempt to keep persistent huge pages more or less
1380 * balanced over allowed nodes.
1381 * Called with hugetlb_lock locked.
1383 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1389 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1391 * If we're returning unused surplus pages, only examine
1392 * nodes with surplus pages.
1394 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1395 !list_empty(&h
->hugepage_freelists
[node
])) {
1397 list_entry(h
->hugepage_freelists
[node
].next
,
1399 list_del(&page
->lru
);
1400 h
->free_huge_pages
--;
1401 h
->free_huge_pages_node
[node
]--;
1403 h
->surplus_huge_pages
--;
1404 h
->surplus_huge_pages_node
[node
]--;
1406 update_and_free_page(h
, page
);
1416 * Dissolve a given free hugepage into free buddy pages. This function does
1417 * nothing for in-use (including surplus) hugepages.
1419 static void dissolve_free_huge_page(struct page
*page
)
1421 spin_lock(&hugetlb_lock
);
1422 if (PageHuge(page
) && !page_count(page
)) {
1423 struct hstate
*h
= page_hstate(page
);
1424 int nid
= page_to_nid(page
);
1425 list_del(&page
->lru
);
1426 h
->free_huge_pages
--;
1427 h
->free_huge_pages_node
[nid
]--;
1428 update_and_free_page(h
, page
);
1430 spin_unlock(&hugetlb_lock
);
1434 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1435 * make specified memory blocks removable from the system.
1436 * Note that start_pfn should aligned with (minimum) hugepage size.
1438 void dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1442 if (!hugepages_supported())
1445 VM_BUG_ON(!IS_ALIGNED(start_pfn
, 1 << minimum_order
));
1446 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
)
1447 dissolve_free_huge_page(pfn_to_page(pfn
));
1451 * There are 3 ways this can get called:
1452 * 1. With vma+addr: we use the VMA's memory policy
1453 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1454 * page from any node, and let the buddy allocator itself figure
1456 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1457 * strictly from 'nid'
1459 static struct page
*__hugetlb_alloc_buddy_huge_page(struct hstate
*h
,
1460 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1462 int order
= huge_page_order(h
);
1463 gfp_t gfp
= htlb_alloc_mask(h
)|__GFP_COMP
|__GFP_REPEAT
|__GFP_NOWARN
;
1464 unsigned int cpuset_mems_cookie
;
1467 * We need a VMA to get a memory policy. If we do not
1468 * have one, we use the 'nid' argument.
1470 * The mempolicy stuff below has some non-inlined bits
1471 * and calls ->vm_ops. That makes it hard to optimize at
1472 * compile-time, even when NUMA is off and it does
1473 * nothing. This helps the compiler optimize it out.
1475 if (!IS_ENABLED(CONFIG_NUMA
) || !vma
) {
1477 * If a specific node is requested, make sure to
1478 * get memory from there, but only when a node
1479 * is explicitly specified.
1481 if (nid
!= NUMA_NO_NODE
)
1482 gfp
|= __GFP_THISNODE
;
1484 * Make sure to call something that can handle
1487 return alloc_pages_node(nid
, gfp
, order
);
1491 * OK, so we have a VMA. Fetch the mempolicy and try to
1492 * allocate a huge page with it. We will only reach this
1493 * when CONFIG_NUMA=y.
1497 struct mempolicy
*mpol
;
1498 struct zonelist
*zl
;
1499 nodemask_t
*nodemask
;
1501 cpuset_mems_cookie
= read_mems_allowed_begin();
1502 zl
= huge_zonelist(vma
, addr
, gfp
, &mpol
, &nodemask
);
1503 mpol_cond_put(mpol
);
1504 page
= __alloc_pages_nodemask(gfp
, order
, zl
, nodemask
);
1507 } while (read_mems_allowed_retry(cpuset_mems_cookie
));
1513 * There are two ways to allocate a huge page:
1514 * 1. When you have a VMA and an address (like a fault)
1515 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1517 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1518 * this case which signifies that the allocation should be done with
1519 * respect for the VMA's memory policy.
1521 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1522 * implies that memory policies will not be taken in to account.
1524 static struct page
*__alloc_buddy_huge_page(struct hstate
*h
,
1525 struct vm_area_struct
*vma
, unsigned long addr
, int nid
)
1530 if (hstate_is_gigantic(h
))
1534 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1535 * This makes sure the caller is picking _one_ of the modes with which
1536 * we can call this function, not both.
1538 if (vma
|| (addr
!= -1)) {
1539 VM_WARN_ON_ONCE(addr
== -1);
1540 VM_WARN_ON_ONCE(nid
!= NUMA_NO_NODE
);
1543 * Assume we will successfully allocate the surplus page to
1544 * prevent racing processes from causing the surplus to exceed
1547 * This however introduces a different race, where a process B
1548 * tries to grow the static hugepage pool while alloc_pages() is
1549 * called by process A. B will only examine the per-node
1550 * counters in determining if surplus huge pages can be
1551 * converted to normal huge pages in adjust_pool_surplus(). A
1552 * won't be able to increment the per-node counter, until the
1553 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1554 * no more huge pages can be converted from surplus to normal
1555 * state (and doesn't try to convert again). Thus, we have a
1556 * case where a surplus huge page exists, the pool is grown, and
1557 * the surplus huge page still exists after, even though it
1558 * should just have been converted to a normal huge page. This
1559 * does not leak memory, though, as the hugepage will be freed
1560 * once it is out of use. It also does not allow the counters to
1561 * go out of whack in adjust_pool_surplus() as we don't modify
1562 * the node values until we've gotten the hugepage and only the
1563 * per-node value is checked there.
1565 spin_lock(&hugetlb_lock
);
1566 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1567 spin_unlock(&hugetlb_lock
);
1571 h
->surplus_huge_pages
++;
1573 spin_unlock(&hugetlb_lock
);
1575 page
= __hugetlb_alloc_buddy_huge_page(h
, vma
, addr
, nid
);
1577 spin_lock(&hugetlb_lock
);
1579 INIT_LIST_HEAD(&page
->lru
);
1580 r_nid
= page_to_nid(page
);
1581 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1582 set_hugetlb_cgroup(page
, NULL
);
1584 * We incremented the global counters already
1586 h
->nr_huge_pages_node
[r_nid
]++;
1587 h
->surplus_huge_pages_node
[r_nid
]++;
1588 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1591 h
->surplus_huge_pages
--;
1592 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1594 spin_unlock(&hugetlb_lock
);
1600 * Allocate a huge page from 'nid'. Note, 'nid' may be
1601 * NUMA_NO_NODE, which means that it may be allocated
1605 struct page
*__alloc_buddy_huge_page_no_mpol(struct hstate
*h
, int nid
)
1607 unsigned long addr
= -1;
1609 return __alloc_buddy_huge_page(h
, NULL
, addr
, nid
);
1613 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1616 struct page
*__alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1617 struct vm_area_struct
*vma
, unsigned long addr
)
1619 return __alloc_buddy_huge_page(h
, vma
, addr
, NUMA_NO_NODE
);
1623 * This allocation function is useful in the context where vma is irrelevant.
1624 * E.g. soft-offlining uses this function because it only cares physical
1625 * address of error page.
1627 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1629 struct page
*page
= NULL
;
1631 spin_lock(&hugetlb_lock
);
1632 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1633 page
= dequeue_huge_page_node(h
, nid
);
1634 spin_unlock(&hugetlb_lock
);
1637 page
= __alloc_buddy_huge_page_no_mpol(h
, nid
);
1643 * Increase the hugetlb pool such that it can accommodate a reservation
1646 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1648 struct list_head surplus_list
;
1649 struct page
*page
, *tmp
;
1651 int needed
, allocated
;
1652 bool alloc_ok
= true;
1654 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1656 h
->resv_huge_pages
+= delta
;
1661 INIT_LIST_HEAD(&surplus_list
);
1665 spin_unlock(&hugetlb_lock
);
1666 for (i
= 0; i
< needed
; i
++) {
1667 page
= __alloc_buddy_huge_page_no_mpol(h
, NUMA_NO_NODE
);
1672 list_add(&page
->lru
, &surplus_list
);
1677 * After retaking hugetlb_lock, we need to recalculate 'needed'
1678 * because either resv_huge_pages or free_huge_pages may have changed.
1680 spin_lock(&hugetlb_lock
);
1681 needed
= (h
->resv_huge_pages
+ delta
) -
1682 (h
->free_huge_pages
+ allocated
);
1687 * We were not able to allocate enough pages to
1688 * satisfy the entire reservation so we free what
1689 * we've allocated so far.
1694 * The surplus_list now contains _at_least_ the number of extra pages
1695 * needed to accommodate the reservation. Add the appropriate number
1696 * of pages to the hugetlb pool and free the extras back to the buddy
1697 * allocator. Commit the entire reservation here to prevent another
1698 * process from stealing the pages as they are added to the pool but
1699 * before they are reserved.
1701 needed
+= allocated
;
1702 h
->resv_huge_pages
+= delta
;
1705 /* Free the needed pages to the hugetlb pool */
1706 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1710 * This page is now managed by the hugetlb allocator and has
1711 * no users -- drop the buddy allocator's reference.
1713 put_page_testzero(page
);
1714 VM_BUG_ON_PAGE(page_count(page
), page
);
1715 enqueue_huge_page(h
, page
);
1718 spin_unlock(&hugetlb_lock
);
1720 /* Free unnecessary surplus pages to the buddy allocator */
1721 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1723 spin_lock(&hugetlb_lock
);
1729 * When releasing a hugetlb pool reservation, any surplus pages that were
1730 * allocated to satisfy the reservation must be explicitly freed if they were
1732 * Called with hugetlb_lock held.
1734 static void return_unused_surplus_pages(struct hstate
*h
,
1735 unsigned long unused_resv_pages
)
1737 unsigned long nr_pages
;
1739 /* Uncommit the reservation */
1740 h
->resv_huge_pages
-= unused_resv_pages
;
1742 /* Cannot return gigantic pages currently */
1743 if (hstate_is_gigantic(h
))
1746 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1749 * We want to release as many surplus pages as possible, spread
1750 * evenly across all nodes with memory. Iterate across these nodes
1751 * until we can no longer free unreserved surplus pages. This occurs
1752 * when the nodes with surplus pages have no free pages.
1753 * free_pool_huge_page() will balance the the freed pages across the
1754 * on-line nodes with memory and will handle the hstate accounting.
1756 while (nr_pages
--) {
1757 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1759 cond_resched_lock(&hugetlb_lock
);
1765 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1766 * are used by the huge page allocation routines to manage reservations.
1768 * vma_needs_reservation is called to determine if the huge page at addr
1769 * within the vma has an associated reservation. If a reservation is
1770 * needed, the value 1 is returned. The caller is then responsible for
1771 * managing the global reservation and subpool usage counts. After
1772 * the huge page has been allocated, vma_commit_reservation is called
1773 * to add the page to the reservation map. If the page allocation fails,
1774 * the reservation must be ended instead of committed. vma_end_reservation
1775 * is called in such cases.
1777 * In the normal case, vma_commit_reservation returns the same value
1778 * as the preceding vma_needs_reservation call. The only time this
1779 * is not the case is if a reserve map was changed between calls. It
1780 * is the responsibility of the caller to notice the difference and
1781 * take appropriate action.
1783 enum vma_resv_mode
{
1788 static long __vma_reservation_common(struct hstate
*h
,
1789 struct vm_area_struct
*vma
, unsigned long addr
,
1790 enum vma_resv_mode mode
)
1792 struct resv_map
*resv
;
1796 resv
= vma_resv_map(vma
);
1800 idx
= vma_hugecache_offset(h
, vma
, addr
);
1802 case VMA_NEEDS_RESV
:
1803 ret
= region_chg(resv
, idx
, idx
+ 1);
1805 case VMA_COMMIT_RESV
:
1806 ret
= region_add(resv
, idx
, idx
+ 1);
1809 region_abort(resv
, idx
, idx
+ 1);
1816 if (vma
->vm_flags
& VM_MAYSHARE
)
1819 return ret
< 0 ? ret
: 0;
1822 static long vma_needs_reservation(struct hstate
*h
,
1823 struct vm_area_struct
*vma
, unsigned long addr
)
1825 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
1828 static long vma_commit_reservation(struct hstate
*h
,
1829 struct vm_area_struct
*vma
, unsigned long addr
)
1831 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
1834 static void vma_end_reservation(struct hstate
*h
,
1835 struct vm_area_struct
*vma
, unsigned long addr
)
1837 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
1840 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
1841 unsigned long addr
, int avoid_reserve
)
1843 struct hugepage_subpool
*spool
= subpool_vma(vma
);
1844 struct hstate
*h
= hstate_vma(vma
);
1846 long map_chg
, map_commit
;
1849 struct hugetlb_cgroup
*h_cg
;
1851 idx
= hstate_index(h
);
1853 * Examine the region/reserve map to determine if the process
1854 * has a reservation for the page to be allocated. A return
1855 * code of zero indicates a reservation exists (no change).
1857 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
1859 return ERR_PTR(-ENOMEM
);
1862 * Processes that did not create the mapping will have no
1863 * reserves as indicated by the region/reserve map. Check
1864 * that the allocation will not exceed the subpool limit.
1865 * Allocations for MAP_NORESERVE mappings also need to be
1866 * checked against any subpool limit.
1868 if (map_chg
|| avoid_reserve
) {
1869 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
1871 vma_end_reservation(h
, vma
, addr
);
1872 return ERR_PTR(-ENOSPC
);
1876 * Even though there was no reservation in the region/reserve
1877 * map, there could be reservations associated with the
1878 * subpool that can be used. This would be indicated if the
1879 * return value of hugepage_subpool_get_pages() is zero.
1880 * However, if avoid_reserve is specified we still avoid even
1881 * the subpool reservations.
1887 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
1889 goto out_subpool_put
;
1891 spin_lock(&hugetlb_lock
);
1893 * glb_chg is passed to indicate whether or not a page must be taken
1894 * from the global free pool (global change). gbl_chg == 0 indicates
1895 * a reservation exists for the allocation.
1897 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
1899 spin_unlock(&hugetlb_lock
);
1900 page
= __alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
1902 goto out_uncharge_cgroup
;
1903 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
1904 SetPagePrivate(page
);
1905 h
->resv_huge_pages
--;
1907 spin_lock(&hugetlb_lock
);
1908 list_move(&page
->lru
, &h
->hugepage_activelist
);
1911 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
1912 spin_unlock(&hugetlb_lock
);
1914 set_page_private(page
, (unsigned long)spool
);
1916 map_commit
= vma_commit_reservation(h
, vma
, addr
);
1917 if (unlikely(map_chg
> map_commit
)) {
1919 * The page was added to the reservation map between
1920 * vma_needs_reservation and vma_commit_reservation.
1921 * This indicates a race with hugetlb_reserve_pages.
1922 * Adjust for the subpool count incremented above AND
1923 * in hugetlb_reserve_pages for the same page. Also,
1924 * the reservation count added in hugetlb_reserve_pages
1925 * no longer applies.
1929 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
1930 hugetlb_acct_memory(h
, -rsv_adjust
);
1934 out_uncharge_cgroup
:
1935 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
1937 if (map_chg
|| avoid_reserve
)
1938 hugepage_subpool_put_pages(spool
, 1);
1939 vma_end_reservation(h
, vma
, addr
);
1940 return ERR_PTR(-ENOSPC
);
1944 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1945 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1946 * where no ERR_VALUE is expected to be returned.
1948 struct page
*alloc_huge_page_noerr(struct vm_area_struct
*vma
,
1949 unsigned long addr
, int avoid_reserve
)
1951 struct page
*page
= alloc_huge_page(vma
, addr
, avoid_reserve
);
1957 int __weak
alloc_bootmem_huge_page(struct hstate
*h
)
1959 struct huge_bootmem_page
*m
;
1962 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
1965 addr
= memblock_virt_alloc_try_nid_nopanic(
1966 huge_page_size(h
), huge_page_size(h
),
1967 0, BOOTMEM_ALLOC_ACCESSIBLE
, node
);
1970 * Use the beginning of the huge page to store the
1971 * huge_bootmem_page struct (until gather_bootmem
1972 * puts them into the mem_map).
1981 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
1982 /* Put them into a private list first because mem_map is not up yet */
1983 list_add(&m
->list
, &huge_boot_pages
);
1988 static void __init
prep_compound_huge_page(struct page
*page
,
1991 if (unlikely(order
> (MAX_ORDER
- 1)))
1992 prep_compound_gigantic_page(page
, order
);
1994 prep_compound_page(page
, order
);
1997 /* Put bootmem huge pages into the standard lists after mem_map is up */
1998 static void __init
gather_bootmem_prealloc(void)
2000 struct huge_bootmem_page
*m
;
2002 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2003 struct hstate
*h
= m
->hstate
;
2006 #ifdef CONFIG_HIGHMEM
2007 page
= pfn_to_page(m
->phys
>> PAGE_SHIFT
);
2008 memblock_free_late(__pa(m
),
2009 sizeof(struct huge_bootmem_page
));
2011 page
= virt_to_page(m
);
2013 WARN_ON(page_count(page
) != 1);
2014 prep_compound_huge_page(page
, h
->order
);
2015 WARN_ON(PageReserved(page
));
2016 prep_new_huge_page(h
, page
, page_to_nid(page
));
2018 * If we had gigantic hugepages allocated at boot time, we need
2019 * to restore the 'stolen' pages to totalram_pages in order to
2020 * fix confusing memory reports from free(1) and another
2021 * side-effects, like CommitLimit going negative.
2023 if (hstate_is_gigantic(h
))
2024 adjust_managed_page_count(page
, 1 << h
->order
);
2028 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2032 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2033 if (hstate_is_gigantic(h
)) {
2034 if (!alloc_bootmem_huge_page(h
))
2036 } else if (!alloc_fresh_huge_page(h
,
2037 &node_states
[N_MEMORY
]))
2040 h
->max_huge_pages
= i
;
2043 static void __init
hugetlb_init_hstates(void)
2047 for_each_hstate(h
) {
2048 if (minimum_order
> huge_page_order(h
))
2049 minimum_order
= huge_page_order(h
);
2051 /* oversize hugepages were init'ed in early boot */
2052 if (!hstate_is_gigantic(h
))
2053 hugetlb_hstate_alloc_pages(h
);
2055 VM_BUG_ON(minimum_order
== UINT_MAX
);
2058 static char * __init
memfmt(char *buf
, unsigned long n
)
2060 if (n
>= (1UL << 30))
2061 sprintf(buf
, "%lu GB", n
>> 30);
2062 else if (n
>= (1UL << 20))
2063 sprintf(buf
, "%lu MB", n
>> 20);
2065 sprintf(buf
, "%lu KB", n
>> 10);
2069 static void __init
report_hugepages(void)
2073 for_each_hstate(h
) {
2075 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2076 memfmt(buf
, huge_page_size(h
)),
2077 h
->free_huge_pages
);
2081 #ifdef CONFIG_HIGHMEM
2082 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2083 nodemask_t
*nodes_allowed
)
2087 if (hstate_is_gigantic(h
))
2090 for_each_node_mask(i
, *nodes_allowed
) {
2091 struct page
*page
, *next
;
2092 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2093 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2094 if (count
>= h
->nr_huge_pages
)
2096 if (PageHighMem(page
))
2098 list_del(&page
->lru
);
2099 update_and_free_page(h
, page
);
2100 h
->free_huge_pages
--;
2101 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2106 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2107 nodemask_t
*nodes_allowed
)
2113 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2114 * balanced by operating on them in a round-robin fashion.
2115 * Returns 1 if an adjustment was made.
2117 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2122 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2125 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2126 if (h
->surplus_huge_pages_node
[node
])
2130 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2131 if (h
->surplus_huge_pages_node
[node
] <
2132 h
->nr_huge_pages_node
[node
])
2139 h
->surplus_huge_pages
+= delta
;
2140 h
->surplus_huge_pages_node
[node
] += delta
;
2144 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2145 static unsigned long set_max_huge_pages(struct hstate
*h
, unsigned long count
,
2146 nodemask_t
*nodes_allowed
)
2148 unsigned long min_count
, ret
;
2150 if (hstate_is_gigantic(h
) && !gigantic_page_supported())
2151 return h
->max_huge_pages
;
2154 * Increase the pool size
2155 * First take pages out of surplus state. Then make up the
2156 * remaining difference by allocating fresh huge pages.
2158 * We might race with __alloc_buddy_huge_page() here and be unable
2159 * to convert a surplus huge page to a normal huge page. That is
2160 * not critical, though, it just means the overall size of the
2161 * pool might be one hugepage larger than it needs to be, but
2162 * within all the constraints specified by the sysctls.
2164 spin_lock(&hugetlb_lock
);
2165 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2166 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2170 while (count
> persistent_huge_pages(h
)) {
2172 * If this allocation races such that we no longer need the
2173 * page, free_huge_page will handle it by freeing the page
2174 * and reducing the surplus.
2176 spin_unlock(&hugetlb_lock
);
2177 if (hstate_is_gigantic(h
))
2178 ret
= alloc_fresh_gigantic_page(h
, nodes_allowed
);
2180 ret
= alloc_fresh_huge_page(h
, nodes_allowed
);
2181 spin_lock(&hugetlb_lock
);
2185 /* Bail for signals. Probably ctrl-c from user */
2186 if (signal_pending(current
))
2191 * Decrease the pool size
2192 * First return free pages to the buddy allocator (being careful
2193 * to keep enough around to satisfy reservations). Then place
2194 * pages into surplus state as needed so the pool will shrink
2195 * to the desired size as pages become free.
2197 * By placing pages into the surplus state independent of the
2198 * overcommit value, we are allowing the surplus pool size to
2199 * exceed overcommit. There are few sane options here. Since
2200 * __alloc_buddy_huge_page() is checking the global counter,
2201 * though, we'll note that we're not allowed to exceed surplus
2202 * and won't grow the pool anywhere else. Not until one of the
2203 * sysctls are changed, or the surplus pages go out of use.
2205 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2206 min_count
= max(count
, min_count
);
2207 try_to_free_low(h
, min_count
, nodes_allowed
);
2208 while (min_count
< persistent_huge_pages(h
)) {
2209 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2211 cond_resched_lock(&hugetlb_lock
);
2213 while (count
< persistent_huge_pages(h
)) {
2214 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2218 ret
= persistent_huge_pages(h
);
2219 spin_unlock(&hugetlb_lock
);
2223 #define HSTATE_ATTR_RO(_name) \
2224 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2226 #define HSTATE_ATTR(_name) \
2227 static struct kobj_attribute _name##_attr = \
2228 __ATTR(_name, 0644, _name##_show, _name##_store)
2230 static struct kobject
*hugepages_kobj
;
2231 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2233 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2235 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2239 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2240 if (hstate_kobjs
[i
] == kobj
) {
2242 *nidp
= NUMA_NO_NODE
;
2246 return kobj_to_node_hstate(kobj
, nidp
);
2249 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2250 struct kobj_attribute
*attr
, char *buf
)
2253 unsigned long nr_huge_pages
;
2256 h
= kobj_to_hstate(kobj
, &nid
);
2257 if (nid
== NUMA_NO_NODE
)
2258 nr_huge_pages
= h
->nr_huge_pages
;
2260 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2262 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2265 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2266 struct hstate
*h
, int nid
,
2267 unsigned long count
, size_t len
)
2270 NODEMASK_ALLOC(nodemask_t
, nodes_allowed
, GFP_KERNEL
| __GFP_NORETRY
);
2272 if (hstate_is_gigantic(h
) && !gigantic_page_supported()) {
2277 if (nid
== NUMA_NO_NODE
) {
2279 * global hstate attribute
2281 if (!(obey_mempolicy
&&
2282 init_nodemask_of_mempolicy(nodes_allowed
))) {
2283 NODEMASK_FREE(nodes_allowed
);
2284 nodes_allowed
= &node_states
[N_MEMORY
];
2286 } else if (nodes_allowed
) {
2288 * per node hstate attribute: adjust count to global,
2289 * but restrict alloc/free to the specified node.
2291 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2292 init_nodemask_of_node(nodes_allowed
, nid
);
2294 nodes_allowed
= &node_states
[N_MEMORY
];
2296 h
->max_huge_pages
= set_max_huge_pages(h
, count
, nodes_allowed
);
2298 if (nodes_allowed
!= &node_states
[N_MEMORY
])
2299 NODEMASK_FREE(nodes_allowed
);
2303 NODEMASK_FREE(nodes_allowed
);
2307 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2308 struct kobject
*kobj
, const char *buf
,
2312 unsigned long count
;
2316 err
= kstrtoul(buf
, 10, &count
);
2320 h
= kobj_to_hstate(kobj
, &nid
);
2321 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2324 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2325 struct kobj_attribute
*attr
, char *buf
)
2327 return nr_hugepages_show_common(kobj
, attr
, buf
);
2330 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2331 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2333 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2335 HSTATE_ATTR(nr_hugepages
);
2340 * hstate attribute for optionally mempolicy-based constraint on persistent
2341 * huge page alloc/free.
2343 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2344 struct kobj_attribute
*attr
, char *buf
)
2346 return nr_hugepages_show_common(kobj
, attr
, buf
);
2349 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2350 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2352 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2354 HSTATE_ATTR(nr_hugepages_mempolicy
);
2358 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2359 struct kobj_attribute
*attr
, char *buf
)
2361 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2362 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2365 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2366 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2369 unsigned long input
;
2370 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2372 if (hstate_is_gigantic(h
))
2375 err
= kstrtoul(buf
, 10, &input
);
2379 spin_lock(&hugetlb_lock
);
2380 h
->nr_overcommit_huge_pages
= input
;
2381 spin_unlock(&hugetlb_lock
);
2385 HSTATE_ATTR(nr_overcommit_hugepages
);
2387 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2388 struct kobj_attribute
*attr
, char *buf
)
2391 unsigned long free_huge_pages
;
2394 h
= kobj_to_hstate(kobj
, &nid
);
2395 if (nid
== NUMA_NO_NODE
)
2396 free_huge_pages
= h
->free_huge_pages
;
2398 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2400 return sprintf(buf
, "%lu\n", free_huge_pages
);
2402 HSTATE_ATTR_RO(free_hugepages
);
2404 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2405 struct kobj_attribute
*attr
, char *buf
)
2407 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2408 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2410 HSTATE_ATTR_RO(resv_hugepages
);
2412 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2413 struct kobj_attribute
*attr
, char *buf
)
2416 unsigned long surplus_huge_pages
;
2419 h
= kobj_to_hstate(kobj
, &nid
);
2420 if (nid
== NUMA_NO_NODE
)
2421 surplus_huge_pages
= h
->surplus_huge_pages
;
2423 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2425 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2427 HSTATE_ATTR_RO(surplus_hugepages
);
2429 static struct attribute
*hstate_attrs
[] = {
2430 &nr_hugepages_attr
.attr
,
2431 &nr_overcommit_hugepages_attr
.attr
,
2432 &free_hugepages_attr
.attr
,
2433 &resv_hugepages_attr
.attr
,
2434 &surplus_hugepages_attr
.attr
,
2436 &nr_hugepages_mempolicy_attr
.attr
,
2441 static struct attribute_group hstate_attr_group
= {
2442 .attrs
= hstate_attrs
,
2445 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2446 struct kobject
**hstate_kobjs
,
2447 struct attribute_group
*hstate_attr_group
)
2450 int hi
= hstate_index(h
);
2452 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2453 if (!hstate_kobjs
[hi
])
2456 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2458 kobject_put(hstate_kobjs
[hi
]);
2463 static void __init
hugetlb_sysfs_init(void)
2468 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2469 if (!hugepages_kobj
)
2472 for_each_hstate(h
) {
2473 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2474 hstate_kobjs
, &hstate_attr_group
);
2476 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2483 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2484 * with node devices in node_devices[] using a parallel array. The array
2485 * index of a node device or _hstate == node id.
2486 * This is here to avoid any static dependency of the node device driver, in
2487 * the base kernel, on the hugetlb module.
2489 struct node_hstate
{
2490 struct kobject
*hugepages_kobj
;
2491 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2493 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2496 * A subset of global hstate attributes for node devices
2498 static struct attribute
*per_node_hstate_attrs
[] = {
2499 &nr_hugepages_attr
.attr
,
2500 &free_hugepages_attr
.attr
,
2501 &surplus_hugepages_attr
.attr
,
2505 static struct attribute_group per_node_hstate_attr_group
= {
2506 .attrs
= per_node_hstate_attrs
,
2510 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2511 * Returns node id via non-NULL nidp.
2513 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2517 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2518 struct node_hstate
*nhs
= &node_hstates
[nid
];
2520 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2521 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2533 * Unregister hstate attributes from a single node device.
2534 * No-op if no hstate attributes attached.
2536 static void hugetlb_unregister_node(struct node
*node
)
2539 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2541 if (!nhs
->hugepages_kobj
)
2542 return; /* no hstate attributes */
2544 for_each_hstate(h
) {
2545 int idx
= hstate_index(h
);
2546 if (nhs
->hstate_kobjs
[idx
]) {
2547 kobject_put(nhs
->hstate_kobjs
[idx
]);
2548 nhs
->hstate_kobjs
[idx
] = NULL
;
2552 kobject_put(nhs
->hugepages_kobj
);
2553 nhs
->hugepages_kobj
= NULL
;
2558 * Register hstate attributes for a single node device.
2559 * No-op if attributes already registered.
2561 static void hugetlb_register_node(struct node
*node
)
2564 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2567 if (nhs
->hugepages_kobj
)
2568 return; /* already allocated */
2570 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2572 if (!nhs
->hugepages_kobj
)
2575 for_each_hstate(h
) {
2576 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2578 &per_node_hstate_attr_group
);
2580 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2581 h
->name
, node
->dev
.id
);
2582 hugetlb_unregister_node(node
);
2589 * hugetlb init time: register hstate attributes for all registered node
2590 * devices of nodes that have memory. All on-line nodes should have
2591 * registered their associated device by this time.
2593 static void __init
hugetlb_register_all_nodes(void)
2597 for_each_node_state(nid
, N_MEMORY
) {
2598 struct node
*node
= node_devices
[nid
];
2599 if (node
->dev
.id
== nid
)
2600 hugetlb_register_node(node
);
2604 * Let the node device driver know we're here so it can
2605 * [un]register hstate attributes on node hotplug.
2607 register_hugetlbfs_with_node(hugetlb_register_node
,
2608 hugetlb_unregister_node
);
2610 #else /* !CONFIG_NUMA */
2612 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2620 static void hugetlb_register_all_nodes(void) { }
2624 static int __init
hugetlb_init(void)
2628 if (!hugepages_supported())
2631 if (!size_to_hstate(default_hstate_size
)) {
2632 default_hstate_size
= HPAGE_SIZE
;
2633 if (!size_to_hstate(default_hstate_size
))
2634 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2636 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2637 if (default_hstate_max_huge_pages
) {
2638 if (!default_hstate
.max_huge_pages
)
2639 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2642 hugetlb_init_hstates();
2643 gather_bootmem_prealloc();
2646 hugetlb_sysfs_init();
2647 hugetlb_register_all_nodes();
2648 hugetlb_cgroup_file_init();
2651 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2653 num_fault_mutexes
= 1;
2655 hugetlb_fault_mutex_table
=
2656 kmalloc(sizeof(struct mutex
) * num_fault_mutexes
, GFP_KERNEL
);
2657 BUG_ON(!hugetlb_fault_mutex_table
);
2659 for (i
= 0; i
< num_fault_mutexes
; i
++)
2660 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2663 subsys_initcall(hugetlb_init
);
2665 /* Should be called on processing a hugepagesz=... option */
2666 void __init
hugetlb_bad_size(void)
2668 parsed_valid_hugepagesz
= false;
2671 void __init
hugetlb_add_hstate(unsigned int order
)
2676 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2677 pr_warn("hugepagesz= specified twice, ignoring\n");
2680 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2682 h
= &hstates
[hugetlb_max_hstate
++];
2684 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2685 h
->nr_huge_pages
= 0;
2686 h
->free_huge_pages
= 0;
2687 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2688 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2689 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2690 h
->next_nid_to_alloc
= first_memory_node
;
2691 h
->next_nid_to_free
= first_memory_node
;
2692 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2693 huge_page_size(h
)/1024);
2698 static int __init
hugetlb_nrpages_setup(char *s
)
2701 static unsigned long *last_mhp
;
2703 if (!parsed_valid_hugepagesz
) {
2704 pr_warn("hugepages = %s preceded by "
2705 "an unsupported hugepagesz, ignoring\n", s
);
2706 parsed_valid_hugepagesz
= true;
2710 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2711 * so this hugepages= parameter goes to the "default hstate".
2713 else if (!hugetlb_max_hstate
)
2714 mhp
= &default_hstate_max_huge_pages
;
2716 mhp
= &parsed_hstate
->max_huge_pages
;
2718 if (mhp
== last_mhp
) {
2719 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2723 if (sscanf(s
, "%lu", mhp
) <= 0)
2727 * Global state is always initialized later in hugetlb_init.
2728 * But we need to allocate >= MAX_ORDER hstates here early to still
2729 * use the bootmem allocator.
2731 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2732 hugetlb_hstate_alloc_pages(parsed_hstate
);
2738 __setup("hugepages=", hugetlb_nrpages_setup
);
2740 static int __init
hugetlb_default_setup(char *s
)
2742 default_hstate_size
= memparse(s
, &s
);
2745 __setup("default_hugepagesz=", hugetlb_default_setup
);
2747 static unsigned int cpuset_mems_nr(unsigned int *array
)
2750 unsigned int nr
= 0;
2752 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2758 #ifdef CONFIG_SYSCTL
2759 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2760 struct ctl_table
*table
, int write
,
2761 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2763 struct hstate
*h
= &default_hstate
;
2764 unsigned long tmp
= h
->max_huge_pages
;
2767 if (!hugepages_supported())
2771 table
->maxlen
= sizeof(unsigned long);
2772 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2777 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
2778 NUMA_NO_NODE
, tmp
, *length
);
2783 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2784 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2787 return hugetlb_sysctl_handler_common(false, table
, write
,
2788 buffer
, length
, ppos
);
2792 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
2793 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2795 return hugetlb_sysctl_handler_common(true, table
, write
,
2796 buffer
, length
, ppos
);
2798 #endif /* CONFIG_NUMA */
2800 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
2801 void __user
*buffer
,
2802 size_t *length
, loff_t
*ppos
)
2804 struct hstate
*h
= &default_hstate
;
2808 if (!hugepages_supported())
2811 tmp
= h
->nr_overcommit_huge_pages
;
2813 if (write
&& hstate_is_gigantic(h
))
2817 table
->maxlen
= sizeof(unsigned long);
2818 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2823 spin_lock(&hugetlb_lock
);
2824 h
->nr_overcommit_huge_pages
= tmp
;
2825 spin_unlock(&hugetlb_lock
);
2831 #endif /* CONFIG_SYSCTL */
2833 void hugetlb_report_meminfo(struct seq_file
*m
)
2835 struct hstate
*h
= &default_hstate
;
2836 if (!hugepages_supported())
2839 "HugePages_Total: %5lu\n"
2840 "HugePages_Free: %5lu\n"
2841 "HugePages_Rsvd: %5lu\n"
2842 "HugePages_Surp: %5lu\n"
2843 "Hugepagesize: %8lu kB\n",
2847 h
->surplus_huge_pages
,
2848 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2851 int hugetlb_report_node_meminfo(int nid
, char *buf
)
2853 struct hstate
*h
= &default_hstate
;
2854 if (!hugepages_supported())
2857 "Node %d HugePages_Total: %5u\n"
2858 "Node %d HugePages_Free: %5u\n"
2859 "Node %d HugePages_Surp: %5u\n",
2860 nid
, h
->nr_huge_pages_node
[nid
],
2861 nid
, h
->free_huge_pages_node
[nid
],
2862 nid
, h
->surplus_huge_pages_node
[nid
]);
2865 void hugetlb_show_meminfo(void)
2870 if (!hugepages_supported())
2873 for_each_node_state(nid
, N_MEMORY
)
2875 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2877 h
->nr_huge_pages_node
[nid
],
2878 h
->free_huge_pages_node
[nid
],
2879 h
->surplus_huge_pages_node
[nid
],
2880 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
2883 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
2885 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
2886 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
2889 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2890 unsigned long hugetlb_total_pages(void)
2893 unsigned long nr_total_pages
= 0;
2896 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
2897 return nr_total_pages
;
2900 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
2904 spin_lock(&hugetlb_lock
);
2906 * When cpuset is configured, it breaks the strict hugetlb page
2907 * reservation as the accounting is done on a global variable. Such
2908 * reservation is completely rubbish in the presence of cpuset because
2909 * the reservation is not checked against page availability for the
2910 * current cpuset. Application can still potentially OOM'ed by kernel
2911 * with lack of free htlb page in cpuset that the task is in.
2912 * Attempt to enforce strict accounting with cpuset is almost
2913 * impossible (or too ugly) because cpuset is too fluid that
2914 * task or memory node can be dynamically moved between cpusets.
2916 * The change of semantics for shared hugetlb mapping with cpuset is
2917 * undesirable. However, in order to preserve some of the semantics,
2918 * we fall back to check against current free page availability as
2919 * a best attempt and hopefully to minimize the impact of changing
2920 * semantics that cpuset has.
2923 if (gather_surplus_pages(h
, delta
) < 0)
2926 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
2927 return_unused_surplus_pages(h
, delta
);
2934 return_unused_surplus_pages(h
, (unsigned long) -delta
);
2937 spin_unlock(&hugetlb_lock
);
2941 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
2943 struct resv_map
*resv
= vma_resv_map(vma
);
2946 * This new VMA should share its siblings reservation map if present.
2947 * The VMA will only ever have a valid reservation map pointer where
2948 * it is being copied for another still existing VMA. As that VMA
2949 * has a reference to the reservation map it cannot disappear until
2950 * after this open call completes. It is therefore safe to take a
2951 * new reference here without additional locking.
2953 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2954 kref_get(&resv
->refs
);
2957 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
2959 struct hstate
*h
= hstate_vma(vma
);
2960 struct resv_map
*resv
= vma_resv_map(vma
);
2961 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2962 unsigned long reserve
, start
, end
;
2965 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
2968 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
2969 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
2971 reserve
= (end
- start
) - region_count(resv
, start
, end
);
2973 kref_put(&resv
->refs
, resv_map_release
);
2977 * Decrement reserve counts. The global reserve count may be
2978 * adjusted if the subpool has a minimum size.
2980 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
2981 hugetlb_acct_memory(h
, -gbl_reserve
);
2986 * We cannot handle pagefaults against hugetlb pages at all. They cause
2987 * handle_mm_fault() to try to instantiate regular-sized pages in the
2988 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2991 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2997 const struct vm_operations_struct hugetlb_vm_ops
= {
2998 .fault
= hugetlb_vm_op_fault
,
2999 .open
= hugetlb_vm_op_open
,
3000 .close
= hugetlb_vm_op_close
,
3003 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3009 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3010 vma
->vm_page_prot
)));
3012 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3013 vma
->vm_page_prot
));
3015 entry
= pte_mkyoung(entry
);
3016 entry
= pte_mkhuge(entry
);
3017 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3022 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3023 unsigned long address
, pte_t
*ptep
)
3027 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3028 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3029 update_mmu_cache(vma
, address
, ptep
);
3032 static int is_hugetlb_entry_migration(pte_t pte
)
3036 if (huge_pte_none(pte
) || pte_present(pte
))
3038 swp
= pte_to_swp_entry(pte
);
3039 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3045 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3049 if (huge_pte_none(pte
) || pte_present(pte
))
3051 swp
= pte_to_swp_entry(pte
);
3052 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3058 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3059 struct vm_area_struct
*vma
)
3061 pte_t
*src_pte
, *dst_pte
, entry
;
3062 struct page
*ptepage
;
3065 struct hstate
*h
= hstate_vma(vma
);
3066 unsigned long sz
= huge_page_size(h
);
3067 unsigned long mmun_start
; /* For mmu_notifiers */
3068 unsigned long mmun_end
; /* For mmu_notifiers */
3071 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3073 mmun_start
= vma
->vm_start
;
3074 mmun_end
= vma
->vm_end
;
3076 mmu_notifier_invalidate_range_start(src
, mmun_start
, mmun_end
);
3078 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3079 spinlock_t
*src_ptl
, *dst_ptl
;
3080 src_pte
= huge_pte_offset(src
, addr
);
3083 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3089 /* If the pagetables are shared don't copy or take references */
3090 if (dst_pte
== src_pte
)
3093 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3094 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3095 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3096 entry
= huge_ptep_get(src_pte
);
3097 if (huge_pte_none(entry
)) { /* skip none entry */
3099 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3100 is_hugetlb_entry_hwpoisoned(entry
))) {
3101 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3103 if (is_write_migration_entry(swp_entry
) && cow
) {
3105 * COW mappings require pages in both
3106 * parent and child to be set to read.
3108 make_migration_entry_read(&swp_entry
);
3109 entry
= swp_entry_to_pte(swp_entry
);
3110 set_huge_pte_at(src
, addr
, src_pte
, entry
);
3112 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3115 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3116 mmu_notifier_invalidate_range(src
, mmun_start
,
3119 entry
= huge_ptep_get(src_pte
);
3120 ptepage
= pte_page(entry
);
3122 page_dup_rmap(ptepage
, true);
3123 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3124 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3126 spin_unlock(src_ptl
);
3127 spin_unlock(dst_ptl
);
3131 mmu_notifier_invalidate_range_end(src
, mmun_start
, mmun_end
);
3136 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3137 unsigned long start
, unsigned long end
,
3138 struct page
*ref_page
)
3140 int force_flush
= 0;
3141 struct mm_struct
*mm
= vma
->vm_mm
;
3142 unsigned long address
;
3147 struct hstate
*h
= hstate_vma(vma
);
3148 unsigned long sz
= huge_page_size(h
);
3149 const unsigned long mmun_start
= start
; /* For mmu_notifiers */
3150 const unsigned long mmun_end
= end
; /* For mmu_notifiers */
3152 WARN_ON(!is_vm_hugetlb_page(vma
));
3153 BUG_ON(start
& ~huge_page_mask(h
));
3154 BUG_ON(end
& ~huge_page_mask(h
));
3156 tlb_start_vma(tlb
, vma
);
3157 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3160 for (; address
< end
; address
+= sz
) {
3161 ptep
= huge_pte_offset(mm
, address
);
3165 ptl
= huge_pte_lock(h
, mm
, ptep
);
3166 if (huge_pmd_unshare(mm
, &address
, ptep
))
3169 pte
= huge_ptep_get(ptep
);
3170 if (huge_pte_none(pte
))
3174 * Migrating hugepage or HWPoisoned hugepage is already
3175 * unmapped and its refcount is dropped, so just clear pte here.
3177 if (unlikely(!pte_present(pte
))) {
3178 huge_pte_clear(mm
, address
, ptep
);
3182 page
= pte_page(pte
);
3184 * If a reference page is supplied, it is because a specific
3185 * page is being unmapped, not a range. Ensure the page we
3186 * are about to unmap is the actual page of interest.
3189 if (page
!= ref_page
)
3193 * Mark the VMA as having unmapped its page so that
3194 * future faults in this VMA will fail rather than
3195 * looking like data was lost
3197 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3200 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3201 tlb_remove_tlb_entry(tlb
, ptep
, address
);
3202 if (huge_pte_dirty(pte
))
3203 set_page_dirty(page
);
3205 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3206 page_remove_rmap(page
, true);
3207 force_flush
= !__tlb_remove_page(tlb
, page
);
3213 /* Bail out after unmapping reference page if supplied */
3222 * mmu_gather ran out of room to batch pages, we break out of
3223 * the PTE lock to avoid doing the potential expensive TLB invalidate
3224 * and page-free while holding it.
3229 if (address
< end
&& !ref_page
)
3232 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3233 tlb_end_vma(tlb
, vma
);
3236 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3237 struct vm_area_struct
*vma
, unsigned long start
,
3238 unsigned long end
, struct page
*ref_page
)
3240 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3243 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3244 * test will fail on a vma being torn down, and not grab a page table
3245 * on its way out. We're lucky that the flag has such an appropriate
3246 * name, and can in fact be safely cleared here. We could clear it
3247 * before the __unmap_hugepage_range above, but all that's necessary
3248 * is to clear it before releasing the i_mmap_rwsem. This works
3249 * because in the context this is called, the VMA is about to be
3250 * destroyed and the i_mmap_rwsem is held.
3252 vma
->vm_flags
&= ~VM_MAYSHARE
;
3255 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3256 unsigned long end
, struct page
*ref_page
)
3258 struct mm_struct
*mm
;
3259 struct mmu_gather tlb
;
3263 tlb_gather_mmu(&tlb
, mm
, start
, end
);
3264 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3265 tlb_finish_mmu(&tlb
, start
, end
);
3269 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3270 * mappping it owns the reserve page for. The intention is to unmap the page
3271 * from other VMAs and let the children be SIGKILLed if they are faulting the
3274 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3275 struct page
*page
, unsigned long address
)
3277 struct hstate
*h
= hstate_vma(vma
);
3278 struct vm_area_struct
*iter_vma
;
3279 struct address_space
*mapping
;
3283 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3284 * from page cache lookup which is in HPAGE_SIZE units.
3286 address
= address
& huge_page_mask(h
);
3287 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3289 mapping
= file_inode(vma
->vm_file
)->i_mapping
;
3292 * Take the mapping lock for the duration of the table walk. As
3293 * this mapping should be shared between all the VMAs,
3294 * __unmap_hugepage_range() is called as the lock is already held
3296 i_mmap_lock_write(mapping
);
3297 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3298 /* Do not unmap the current VMA */
3299 if (iter_vma
== vma
)
3303 * Shared VMAs have their own reserves and do not affect
3304 * MAP_PRIVATE accounting but it is possible that a shared
3305 * VMA is using the same page so check and skip such VMAs.
3307 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3311 * Unmap the page from other VMAs without their own reserves.
3312 * They get marked to be SIGKILLed if they fault in these
3313 * areas. This is because a future no-page fault on this VMA
3314 * could insert a zeroed page instead of the data existing
3315 * from the time of fork. This would look like data corruption
3317 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3318 unmap_hugepage_range(iter_vma
, address
,
3319 address
+ huge_page_size(h
), page
);
3321 i_mmap_unlock_write(mapping
);
3325 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3326 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3327 * cannot race with other handlers or page migration.
3328 * Keep the pte_same checks anyway to make transition from the mutex easier.
3330 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3331 unsigned long address
, pte_t
*ptep
, pte_t pte
,
3332 struct page
*pagecache_page
, spinlock_t
*ptl
)
3334 struct hstate
*h
= hstate_vma(vma
);
3335 struct page
*old_page
, *new_page
;
3336 int ret
= 0, outside_reserve
= 0;
3337 unsigned long mmun_start
; /* For mmu_notifiers */
3338 unsigned long mmun_end
; /* For mmu_notifiers */
3340 old_page
= pte_page(pte
);
3343 /* If no-one else is actually using this page, avoid the copy
3344 * and just make the page writable */
3345 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3346 page_move_anon_rmap(old_page
, vma
, address
);
3347 set_huge_ptep_writable(vma
, address
, ptep
);
3352 * If the process that created a MAP_PRIVATE mapping is about to
3353 * perform a COW due to a shared page count, attempt to satisfy
3354 * the allocation without using the existing reserves. The pagecache
3355 * page is used to determine if the reserve at this address was
3356 * consumed or not. If reserves were used, a partial faulted mapping
3357 * at the time of fork() could consume its reserves on COW instead
3358 * of the full address range.
3360 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3361 old_page
!= pagecache_page
)
3362 outside_reserve
= 1;
3367 * Drop page table lock as buddy allocator may be called. It will
3368 * be acquired again before returning to the caller, as expected.
3371 new_page
= alloc_huge_page(vma
, address
, outside_reserve
);
3373 if (IS_ERR(new_page
)) {
3375 * If a process owning a MAP_PRIVATE mapping fails to COW,
3376 * it is due to references held by a child and an insufficient
3377 * huge page pool. To guarantee the original mappers
3378 * reliability, unmap the page from child processes. The child
3379 * may get SIGKILLed if it later faults.
3381 if (outside_reserve
) {
3383 BUG_ON(huge_pte_none(pte
));
3384 unmap_ref_private(mm
, vma
, old_page
, address
);
3385 BUG_ON(huge_pte_none(pte
));
3387 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
3389 pte_same(huge_ptep_get(ptep
), pte
)))
3390 goto retry_avoidcopy
;
3392 * race occurs while re-acquiring page table
3393 * lock, and our job is done.
3398 ret
= (PTR_ERR(new_page
) == -ENOMEM
) ?
3399 VM_FAULT_OOM
: VM_FAULT_SIGBUS
;
3400 goto out_release_old
;
3404 * When the original hugepage is shared one, it does not have
3405 * anon_vma prepared.
3407 if (unlikely(anon_vma_prepare(vma
))) {
3409 goto out_release_all
;
3412 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3413 pages_per_huge_page(h
));
3414 __SetPageUptodate(new_page
);
3415 set_page_huge_active(new_page
);
3417 mmun_start
= address
& huge_page_mask(h
);
3418 mmun_end
= mmun_start
+ huge_page_size(h
);
3419 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
3422 * Retake the page table lock to check for racing updates
3423 * before the page tables are altered
3426 ptep
= huge_pte_offset(mm
, address
& huge_page_mask(h
));
3427 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3428 ClearPagePrivate(new_page
);
3431 huge_ptep_clear_flush(vma
, address
, ptep
);
3432 mmu_notifier_invalidate_range(mm
, mmun_start
, mmun_end
);
3433 set_huge_pte_at(mm
, address
, ptep
,
3434 make_huge_pte(vma
, new_page
, 1));
3435 page_remove_rmap(old_page
, true);
3436 hugepage_add_new_anon_rmap(new_page
, vma
, address
);
3437 /* Make the old page be freed below */
3438 new_page
= old_page
;
3441 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
3447 spin_lock(ptl
); /* Caller expects lock to be held */
3451 /* Return the pagecache page at a given address within a VMA */
3452 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3453 struct vm_area_struct
*vma
, unsigned long address
)
3455 struct address_space
*mapping
;
3458 mapping
= vma
->vm_file
->f_mapping
;
3459 idx
= vma_hugecache_offset(h
, vma
, address
);
3461 return find_lock_page(mapping
, idx
);
3465 * Return whether there is a pagecache page to back given address within VMA.
3466 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3468 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3469 struct vm_area_struct
*vma
, unsigned long address
)
3471 struct address_space
*mapping
;
3475 mapping
= vma
->vm_file
->f_mapping
;
3476 idx
= vma_hugecache_offset(h
, vma
, address
);
3478 page
= find_get_page(mapping
, idx
);
3481 return page
!= NULL
;
3484 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3487 struct inode
*inode
= mapping
->host
;
3488 struct hstate
*h
= hstate_inode(inode
);
3489 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3493 ClearPagePrivate(page
);
3495 spin_lock(&inode
->i_lock
);
3496 inode
->i_blocks
+= blocks_per_huge_page(h
);
3497 spin_unlock(&inode
->i_lock
);
3501 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3502 struct address_space
*mapping
, pgoff_t idx
,
3503 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3505 struct hstate
*h
= hstate_vma(vma
);
3506 int ret
= VM_FAULT_SIGBUS
;
3514 * Currently, we are forced to kill the process in the event the
3515 * original mapper has unmapped pages from the child due to a failed
3516 * COW. Warn that such a situation has occurred as it may not be obvious
3518 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3519 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3525 * Use page lock to guard against racing truncation
3526 * before we get page_table_lock.
3529 page
= find_lock_page(mapping
, idx
);
3531 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3534 page
= alloc_huge_page(vma
, address
, 0);
3536 ret
= PTR_ERR(page
);
3540 ret
= VM_FAULT_SIGBUS
;
3543 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3544 __SetPageUptodate(page
);
3545 set_page_huge_active(page
);
3547 if (vma
->vm_flags
& VM_MAYSHARE
) {
3548 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3557 if (unlikely(anon_vma_prepare(vma
))) {
3559 goto backout_unlocked
;
3565 * If memory error occurs between mmap() and fault, some process
3566 * don't have hwpoisoned swap entry for errored virtual address.
3567 * So we need to block hugepage fault by PG_hwpoison bit check.
3569 if (unlikely(PageHWPoison(page
))) {
3570 ret
= VM_FAULT_HWPOISON
|
3571 VM_FAULT_SET_HINDEX(hstate_index(h
));
3572 goto backout_unlocked
;
3577 * If we are going to COW a private mapping later, we examine the
3578 * pending reservations for this page now. This will ensure that
3579 * any allocations necessary to record that reservation occur outside
3582 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3583 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3585 goto backout_unlocked
;
3587 /* Just decrements count, does not deallocate */
3588 vma_end_reservation(h
, vma
, address
);
3591 ptl
= huge_pte_lockptr(h
, mm
, ptep
);
3593 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3598 if (!huge_pte_none(huge_ptep_get(ptep
)))
3602 ClearPagePrivate(page
);
3603 hugepage_add_new_anon_rmap(page
, vma
, address
);
3605 page_dup_rmap(page
, true);
3606 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
3607 && (vma
->vm_flags
& VM_SHARED
)));
3608 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
3610 hugetlb_count_add(pages_per_huge_page(h
), mm
);
3611 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3612 /* Optimization, do the COW without a second fault */
3613 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
, page
, ptl
);
3630 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3631 struct vm_area_struct
*vma
,
3632 struct address_space
*mapping
,
3633 pgoff_t idx
, unsigned long address
)
3635 unsigned long key
[2];
3638 if (vma
->vm_flags
& VM_SHARED
) {
3639 key
[0] = (unsigned long) mapping
;
3642 key
[0] = (unsigned long) mm
;
3643 key
[1] = address
>> huge_page_shift(h
);
3646 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
3648 return hash
& (num_fault_mutexes
- 1);
3652 * For uniprocesor systems we always use a single mutex, so just
3653 * return 0 and avoid the hashing overhead.
3655 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct mm_struct
*mm
,
3656 struct vm_area_struct
*vma
,
3657 struct address_space
*mapping
,
3658 pgoff_t idx
, unsigned long address
)
3664 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3665 unsigned long address
, unsigned int flags
)
3672 struct page
*page
= NULL
;
3673 struct page
*pagecache_page
= NULL
;
3674 struct hstate
*h
= hstate_vma(vma
);
3675 struct address_space
*mapping
;
3676 int need_wait_lock
= 0;
3678 address
&= huge_page_mask(h
);
3680 ptep
= huge_pte_offset(mm
, address
);
3682 entry
= huge_ptep_get(ptep
);
3683 if (unlikely(is_hugetlb_entry_migration(entry
))) {
3684 migration_entry_wait_huge(vma
, mm
, ptep
);
3686 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
3687 return VM_FAULT_HWPOISON_LARGE
|
3688 VM_FAULT_SET_HINDEX(hstate_index(h
));
3690 ptep
= huge_pte_alloc(mm
, address
, huge_page_size(h
));
3692 return VM_FAULT_OOM
;
3695 mapping
= vma
->vm_file
->f_mapping
;
3696 idx
= vma_hugecache_offset(h
, vma
, address
);
3699 * Serialize hugepage allocation and instantiation, so that we don't
3700 * get spurious allocation failures if two CPUs race to instantiate
3701 * the same page in the page cache.
3703 hash
= hugetlb_fault_mutex_hash(h
, mm
, vma
, mapping
, idx
, address
);
3704 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3706 entry
= huge_ptep_get(ptep
);
3707 if (huge_pte_none(entry
)) {
3708 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
3715 * entry could be a migration/hwpoison entry at this point, so this
3716 * check prevents the kernel from going below assuming that we have
3717 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3718 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3721 if (!pte_present(entry
))
3725 * If we are going to COW the mapping later, we examine the pending
3726 * reservations for this page now. This will ensure that any
3727 * allocations necessary to record that reservation occur outside the
3728 * spinlock. For private mappings, we also lookup the pagecache
3729 * page now as it is used to determine if a reservation has been
3732 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
3733 if (vma_needs_reservation(h
, vma
, address
) < 0) {
3737 /* Just decrements count, does not deallocate */
3738 vma_end_reservation(h
, vma
, address
);
3740 if (!(vma
->vm_flags
& VM_MAYSHARE
))
3741 pagecache_page
= hugetlbfs_pagecache_page(h
,
3745 ptl
= huge_pte_lock(h
, mm
, ptep
);
3747 /* Check for a racing update before calling hugetlb_cow */
3748 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
3752 * hugetlb_cow() requires page locks of pte_page(entry) and
3753 * pagecache_page, so here we need take the former one
3754 * when page != pagecache_page or !pagecache_page.
3756 page
= pte_page(entry
);
3757 if (page
!= pagecache_page
)
3758 if (!trylock_page(page
)) {
3765 if (flags
& FAULT_FLAG_WRITE
) {
3766 if (!huge_pte_write(entry
)) {
3767 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
,
3768 pagecache_page
, ptl
);
3771 entry
= huge_pte_mkdirty(entry
);
3773 entry
= pte_mkyoung(entry
);
3774 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
,
3775 flags
& FAULT_FLAG_WRITE
))
3776 update_mmu_cache(vma
, address
, ptep
);
3778 if (page
!= pagecache_page
)
3784 if (pagecache_page
) {
3785 unlock_page(pagecache_page
);
3786 put_page(pagecache_page
);
3789 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3791 * Generally it's safe to hold refcount during waiting page lock. But
3792 * here we just wait to defer the next page fault to avoid busy loop and
3793 * the page is not used after unlocked before returning from the current
3794 * page fault. So we are safe from accessing freed page, even if we wait
3795 * here without taking refcount.
3798 wait_on_page_locked(page
);
3802 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3803 struct page
**pages
, struct vm_area_struct
**vmas
,
3804 unsigned long *position
, unsigned long *nr_pages
,
3805 long i
, unsigned int flags
)
3807 unsigned long pfn_offset
;
3808 unsigned long vaddr
= *position
;
3809 unsigned long remainder
= *nr_pages
;
3810 struct hstate
*h
= hstate_vma(vma
);
3812 while (vaddr
< vma
->vm_end
&& remainder
) {
3814 spinlock_t
*ptl
= NULL
;
3819 * If we have a pending SIGKILL, don't keep faulting pages and
3820 * potentially allocating memory.
3822 if (unlikely(fatal_signal_pending(current
))) {
3828 * Some archs (sparc64, sh*) have multiple pte_ts to
3829 * each hugepage. We have to make sure we get the
3830 * first, for the page indexing below to work.
3832 * Note that page table lock is not held when pte is null.
3834 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
));
3836 ptl
= huge_pte_lock(h
, mm
, pte
);
3837 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
3840 * When coredumping, it suits get_dump_page if we just return
3841 * an error where there's an empty slot with no huge pagecache
3842 * to back it. This way, we avoid allocating a hugepage, and
3843 * the sparse dumpfile avoids allocating disk blocks, but its
3844 * huge holes still show up with zeroes where they need to be.
3846 if (absent
&& (flags
& FOLL_DUMP
) &&
3847 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
3855 * We need call hugetlb_fault for both hugepages under migration
3856 * (in which case hugetlb_fault waits for the migration,) and
3857 * hwpoisoned hugepages (in which case we need to prevent the
3858 * caller from accessing to them.) In order to do this, we use
3859 * here is_swap_pte instead of is_hugetlb_entry_migration and
3860 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3861 * both cases, and because we can't follow correct pages
3862 * directly from any kind of swap entries.
3864 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
3865 ((flags
& FOLL_WRITE
) &&
3866 !huge_pte_write(huge_ptep_get(pte
)))) {
3871 ret
= hugetlb_fault(mm
, vma
, vaddr
,
3872 (flags
& FOLL_WRITE
) ? FAULT_FLAG_WRITE
: 0);
3873 if (!(ret
& VM_FAULT_ERROR
))
3880 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
3881 page
= pte_page(huge_ptep_get(pte
));
3884 pages
[i
] = mem_map_offset(page
, pfn_offset
);
3895 if (vaddr
< vma
->vm_end
&& remainder
&&
3896 pfn_offset
< pages_per_huge_page(h
)) {
3898 * We use pfn_offset to avoid touching the pageframes
3899 * of this compound page.
3905 *nr_pages
= remainder
;
3908 return i
? i
: -EFAULT
;
3911 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
3912 unsigned long address
, unsigned long end
, pgprot_t newprot
)
3914 struct mm_struct
*mm
= vma
->vm_mm
;
3915 unsigned long start
= address
;
3918 struct hstate
*h
= hstate_vma(vma
);
3919 unsigned long pages
= 0;
3921 BUG_ON(address
>= end
);
3922 flush_cache_range(vma
, address
, end
);
3924 mmu_notifier_invalidate_range_start(mm
, start
, end
);
3925 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
3926 for (; address
< end
; address
+= huge_page_size(h
)) {
3928 ptep
= huge_pte_offset(mm
, address
);
3931 ptl
= huge_pte_lock(h
, mm
, ptep
);
3932 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3937 pte
= huge_ptep_get(ptep
);
3938 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
3942 if (unlikely(is_hugetlb_entry_migration(pte
))) {
3943 swp_entry_t entry
= pte_to_swp_entry(pte
);
3945 if (is_write_migration_entry(entry
)) {
3948 make_migration_entry_read(&entry
);
3949 newpte
= swp_entry_to_pte(entry
);
3950 set_huge_pte_at(mm
, address
, ptep
, newpte
);
3956 if (!huge_pte_none(pte
)) {
3957 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3958 pte
= pte_mkhuge(huge_pte_modify(pte
, newprot
));
3959 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
3960 set_huge_pte_at(mm
, address
, ptep
, pte
);
3966 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
3967 * may have cleared our pud entry and done put_page on the page table:
3968 * once we release i_mmap_rwsem, another task can do the final put_page
3969 * and that page table be reused and filled with junk.
3971 flush_tlb_range(vma
, start
, end
);
3972 mmu_notifier_invalidate_range(mm
, start
, end
);
3973 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
3974 mmu_notifier_invalidate_range_end(mm
, start
, end
);
3976 return pages
<< h
->order
;
3979 int hugetlb_reserve_pages(struct inode
*inode
,
3981 struct vm_area_struct
*vma
,
3982 vm_flags_t vm_flags
)
3985 struct hstate
*h
= hstate_inode(inode
);
3986 struct hugepage_subpool
*spool
= subpool_inode(inode
);
3987 struct resv_map
*resv_map
;
3991 * Only apply hugepage reservation if asked. At fault time, an
3992 * attempt will be made for VM_NORESERVE to allocate a page
3993 * without using reserves
3995 if (vm_flags
& VM_NORESERVE
)
3999 * Shared mappings base their reservation on the number of pages that
4000 * are already allocated on behalf of the file. Private mappings need
4001 * to reserve the full area even if read-only as mprotect() may be
4002 * called to make the mapping read-write. Assume !vma is a shm mapping
4004 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4005 resv_map
= inode_resv_map(inode
);
4007 chg
= region_chg(resv_map
, from
, to
);
4010 resv_map
= resv_map_alloc();
4016 set_vma_resv_map(vma
, resv_map
);
4017 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4026 * There must be enough pages in the subpool for the mapping. If
4027 * the subpool has a minimum size, there may be some global
4028 * reservations already in place (gbl_reserve).
4030 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4031 if (gbl_reserve
< 0) {
4037 * Check enough hugepages are available for the reservation.
4038 * Hand the pages back to the subpool if there are not
4040 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4042 /* put back original number of pages, chg */
4043 (void)hugepage_subpool_put_pages(spool
, chg
);
4048 * Account for the reservations made. Shared mappings record regions
4049 * that have reservations as they are shared by multiple VMAs.
4050 * When the last VMA disappears, the region map says how much
4051 * the reservation was and the page cache tells how much of
4052 * the reservation was consumed. Private mappings are per-VMA and
4053 * only the consumed reservations are tracked. When the VMA
4054 * disappears, the original reservation is the VMA size and the
4055 * consumed reservations are stored in the map. Hence, nothing
4056 * else has to be done for private mappings here
4058 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4059 long add
= region_add(resv_map
, from
, to
);
4061 if (unlikely(chg
> add
)) {
4063 * pages in this range were added to the reserve
4064 * map between region_chg and region_add. This
4065 * indicates a race with alloc_huge_page. Adjust
4066 * the subpool and reserve counts modified above
4067 * based on the difference.
4071 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4073 hugetlb_acct_memory(h
, -rsv_adjust
);
4078 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4079 region_abort(resv_map
, from
, to
);
4080 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4081 kref_put(&resv_map
->refs
, resv_map_release
);
4085 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4088 struct hstate
*h
= hstate_inode(inode
);
4089 struct resv_map
*resv_map
= inode_resv_map(inode
);
4091 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4095 chg
= region_del(resv_map
, start
, end
);
4097 * region_del() can fail in the rare case where a region
4098 * must be split and another region descriptor can not be
4099 * allocated. If end == LONG_MAX, it will not fail.
4105 spin_lock(&inode
->i_lock
);
4106 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4107 spin_unlock(&inode
->i_lock
);
4110 * If the subpool has a minimum size, the number of global
4111 * reservations to be released may be adjusted.
4113 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4114 hugetlb_acct_memory(h
, -gbl_reserve
);
4119 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4120 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4121 struct vm_area_struct
*vma
,
4122 unsigned long addr
, pgoff_t idx
)
4124 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4126 unsigned long sbase
= saddr
& PUD_MASK
;
4127 unsigned long s_end
= sbase
+ PUD_SIZE
;
4129 /* Allow segments to share if only one is marked locked */
4130 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4131 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4134 * match the virtual addresses, permission and the alignment of the
4137 if (pmd_index(addr
) != pmd_index(saddr
) ||
4138 vm_flags
!= svm_flags
||
4139 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4145 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4147 unsigned long base
= addr
& PUD_MASK
;
4148 unsigned long end
= base
+ PUD_SIZE
;
4151 * check on proper vm_flags and page table alignment
4153 if (vma
->vm_flags
& VM_MAYSHARE
&&
4154 vma
->vm_start
<= base
&& end
<= vma
->vm_end
)
4160 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4161 * and returns the corresponding pte. While this is not necessary for the
4162 * !shared pmd case because we can allocate the pmd later as well, it makes the
4163 * code much cleaner. pmd allocation is essential for the shared case because
4164 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4165 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4166 * bad pmd for sharing.
4168 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4170 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4171 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4172 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4174 struct vm_area_struct
*svma
;
4175 unsigned long saddr
;
4180 if (!vma_shareable(vma
, addr
))
4181 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4183 i_mmap_lock_write(mapping
);
4184 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4188 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4190 spte
= huge_pte_offset(svma
->vm_mm
, saddr
);
4193 get_page(virt_to_page(spte
));
4202 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, spte
);
4204 if (pud_none(*pud
)) {
4205 pud_populate(mm
, pud
,
4206 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4208 put_page(virt_to_page(spte
));
4213 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4214 i_mmap_unlock_write(mapping
);
4219 * unmap huge page backed by shared pte.
4221 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4222 * indicated by page_count > 1, unmap is achieved by clearing pud and
4223 * decrementing the ref count. If count == 1, the pte page is not shared.
4225 * called with page table lock held.
4227 * returns: 1 successfully unmapped a shared pte page
4228 * 0 the underlying pte page is not shared, or it is the last user
4230 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4232 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4233 pud_t
*pud
= pud_offset(pgd
, *addr
);
4235 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4236 if (page_count(virt_to_page(ptep
)) == 1)
4240 put_page(virt_to_page(ptep
));
4242 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4245 #define want_pmd_share() (1)
4246 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4247 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4252 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4256 #define want_pmd_share() (0)
4257 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4259 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4260 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4261 unsigned long addr
, unsigned long sz
)
4267 pgd
= pgd_offset(mm
, addr
);
4268 pud
= pud_alloc(mm
, pgd
, addr
);
4270 if (sz
== PUD_SIZE
) {
4273 BUG_ON(sz
!= PMD_SIZE
);
4274 if (want_pmd_share() && pud_none(*pud
))
4275 pte
= huge_pmd_share(mm
, addr
, pud
);
4277 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4280 BUG_ON(pte
&& !pte_none(*pte
) && !pte_huge(*pte
));
4285 pte_t
*huge_pte_offset(struct mm_struct
*mm
, unsigned long addr
)
4291 pgd
= pgd_offset(mm
, addr
);
4292 if (pgd_present(*pgd
)) {
4293 pud
= pud_offset(pgd
, addr
);
4294 if (pud_present(*pud
)) {
4296 return (pte_t
*)pud
;
4297 pmd
= pmd_offset(pud
, addr
);
4300 return (pte_t
*) pmd
;
4303 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4306 * These functions are overwritable if your architecture needs its own
4309 struct page
* __weak
4310 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
4313 return ERR_PTR(-EINVAL
);
4316 struct page
* __weak
4317 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
4318 pmd_t
*pmd
, int flags
)
4320 struct page
*page
= NULL
;
4323 ptl
= pmd_lockptr(mm
, pmd
);
4326 * make sure that the address range covered by this pmd is not
4327 * unmapped from other threads.
4329 if (!pmd_huge(*pmd
))
4331 if (pmd_present(*pmd
)) {
4332 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
4333 if (flags
& FOLL_GET
)
4336 if (is_hugetlb_entry_migration(huge_ptep_get((pte_t
*)pmd
))) {
4338 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
4342 * hwpoisoned entry is treated as no_page_table in
4343 * follow_page_mask().
4351 struct page
* __weak
4352 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
4353 pud_t
*pud
, int flags
)
4355 if (flags
& FOLL_GET
)
4358 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
4361 #ifdef CONFIG_MEMORY_FAILURE
4364 * This function is called from memory failure code.
4365 * Assume the caller holds page lock of the head page.
4367 int dequeue_hwpoisoned_huge_page(struct page
*hpage
)
4369 struct hstate
*h
= page_hstate(hpage
);
4370 int nid
= page_to_nid(hpage
);
4373 spin_lock(&hugetlb_lock
);
4375 * Just checking !page_huge_active is not enough, because that could be
4376 * an isolated/hwpoisoned hugepage (which have >0 refcount).
4378 if (!page_huge_active(hpage
) && !page_count(hpage
)) {
4380 * Hwpoisoned hugepage isn't linked to activelist or freelist,
4381 * but dangling hpage->lru can trigger list-debug warnings
4382 * (this happens when we call unpoison_memory() on it),
4383 * so let it point to itself with list_del_init().
4385 list_del_init(&hpage
->lru
);
4386 set_page_refcounted(hpage
);
4387 h
->free_huge_pages
--;
4388 h
->free_huge_pages_node
[nid
]--;
4391 spin_unlock(&hugetlb_lock
);
4396 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
4400 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4401 spin_lock(&hugetlb_lock
);
4402 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
4406 clear_page_huge_active(page
);
4407 list_move_tail(&page
->lru
, list
);
4409 spin_unlock(&hugetlb_lock
);
4413 void putback_active_hugepage(struct page
*page
)
4415 VM_BUG_ON_PAGE(!PageHead(page
), page
);
4416 spin_lock(&hugetlb_lock
);
4417 set_page_huge_active(page
);
4418 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
4419 spin_unlock(&hugetlb_lock
);