1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/mmdebug.h>
23 #include <linux/sched/signal.h>
24 #include <linux/rmap.h>
25 #include <linux/string_helpers.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
28 #include <linux/jhash.h>
29 #include <linux/numa.h>
32 #include <asm/pgtable.h>
36 #include <linux/hugetlb.h>
37 #include <linux/hugetlb_cgroup.h>
38 #include <linux/node.h>
39 #include <linux/userfaultfd_k.h>
40 #include <linux/page_owner.h>
43 int hugetlb_max_hstate __read_mostly
;
44 unsigned int default_hstate_idx
;
45 struct hstate hstates
[HUGE_MAX_HSTATE
];
47 * Minimum page order among possible hugepage sizes, set to a proper value
50 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
52 __initdata
LIST_HEAD(huge_boot_pages
);
54 /* for command line parsing */
55 static struct hstate
* __initdata parsed_hstate
;
56 static unsigned long __initdata default_hstate_max_huge_pages
;
57 static unsigned long __initdata default_hstate_size
;
58 static bool __initdata parsed_valid_hugepagesz
= true;
61 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
62 * free_huge_pages, and surplus_huge_pages.
64 DEFINE_SPINLOCK(hugetlb_lock
);
67 * Serializes faults on the same logical page. This is used to
68 * prevent spurious OOMs when the hugepage pool is fully utilized.
70 static int num_fault_mutexes
;
71 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
73 /* Forward declaration */
74 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
76 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
78 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
80 spin_unlock(&spool
->lock
);
82 /* If no pages are used, and no other handles to the subpool
83 * remain, give up any reservations mased on minimum size and
86 if (spool
->min_hpages
!= -1)
87 hugetlb_acct_memory(spool
->hstate
,
93 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
96 struct hugepage_subpool
*spool
;
98 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
102 spin_lock_init(&spool
->lock
);
104 spool
->max_hpages
= max_hpages
;
106 spool
->min_hpages
= min_hpages
;
108 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
112 spool
->rsv_hpages
= min_hpages
;
117 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
119 spin_lock(&spool
->lock
);
120 BUG_ON(!spool
->count
);
122 unlock_or_release_subpool(spool
);
126 * Subpool accounting for allocating and reserving pages.
127 * Return -ENOMEM if there are not enough resources to satisfy the
128 * the request. Otherwise, return the number of pages by which the
129 * global pools must be adjusted (upward). The returned value may
130 * only be different than the passed value (delta) in the case where
131 * a subpool minimum size must be manitained.
133 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
141 spin_lock(&spool
->lock
);
143 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
144 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
145 spool
->used_hpages
+= delta
;
152 /* minimum size accounting */
153 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
154 if (delta
> spool
->rsv_hpages
) {
156 * Asking for more reserves than those already taken on
157 * behalf of subpool. Return difference.
159 ret
= delta
- spool
->rsv_hpages
;
160 spool
->rsv_hpages
= 0;
162 ret
= 0; /* reserves already accounted for */
163 spool
->rsv_hpages
-= delta
;
168 spin_unlock(&spool
->lock
);
173 * Subpool accounting for freeing and unreserving pages.
174 * Return the number of global page reservations that must be dropped.
175 * The return value may only be different than the passed value (delta)
176 * in the case where a subpool minimum size must be maintained.
178 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
186 spin_lock(&spool
->lock
);
188 if (spool
->max_hpages
!= -1) /* maximum size accounting */
189 spool
->used_hpages
-= delta
;
191 /* minimum size accounting */
192 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
193 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
196 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
198 spool
->rsv_hpages
+= delta
;
199 if (spool
->rsv_hpages
> spool
->min_hpages
)
200 spool
->rsv_hpages
= spool
->min_hpages
;
204 * If hugetlbfs_put_super couldn't free spool due to an outstanding
205 * quota reference, free it now.
207 unlock_or_release_subpool(spool
);
212 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
214 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
217 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
219 return subpool_inode(file_inode(vma
->vm_file
));
223 * Region tracking -- allows tracking of reservations and instantiated pages
224 * across the pages in a mapping.
226 * The region data structures are embedded into a resv_map and protected
227 * by a resv_map's lock. The set of regions within the resv_map represent
228 * reservations for huge pages, or huge pages that have already been
229 * instantiated within the map. The from and to elements are huge page
230 * indicies into the associated mapping. from indicates the starting index
231 * of the region. to represents the first index past the end of the region.
233 * For example, a file region structure with from == 0 and to == 4 represents
234 * four huge pages in a mapping. It is important to note that the to element
235 * represents the first element past the end of the region. This is used in
236 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
238 * Interval notation of the form [from, to) will be used to indicate that
239 * the endpoint from is inclusive and to is exclusive.
242 struct list_head link
;
248 * Add the huge page range represented by [f, t) to the reserve
249 * map. In the normal case, existing regions will be expanded
250 * to accommodate the specified range. Sufficient regions should
251 * exist for expansion due to the previous call to region_chg
252 * with the same range. However, it is possible that region_del
253 * could have been called after region_chg and modifed the map
254 * in such a way that no region exists to be expanded. In this
255 * case, pull a region descriptor from the cache associated with
256 * the map and use that for the new range.
258 * Return the number of new huge pages added to the map. This
259 * number is greater than or equal to zero.
261 static long region_add(struct resv_map
*resv
, long f
, long t
)
263 struct list_head
*head
= &resv
->regions
;
264 struct file_region
*rg
, *nrg
, *trg
;
267 spin_lock(&resv
->lock
);
268 /* Locate the region we are either in or before. */
269 list_for_each_entry(rg
, head
, link
)
274 * If no region exists which can be expanded to include the
275 * specified range, the list must have been modified by an
276 * interleving call to region_del(). Pull a region descriptor
277 * from the cache and use it for this range.
279 if (&rg
->link
== head
|| t
< rg
->from
) {
280 VM_BUG_ON(resv
->region_cache_count
<= 0);
282 resv
->region_cache_count
--;
283 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
285 list_del(&nrg
->link
);
289 list_add(&nrg
->link
, rg
->link
.prev
);
295 /* Round our left edge to the current segment if it encloses us. */
299 /* Check for and consume any regions we now overlap with. */
301 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
302 if (&rg
->link
== head
)
307 /* If this area reaches higher then extend our area to
308 * include it completely. If this is not the first area
309 * which we intend to reuse, free it. */
313 /* Decrement return value by the deleted range.
314 * Another range will span this area so that by
315 * end of routine add will be >= zero
317 add
-= (rg
->to
- rg
->from
);
323 add
+= (nrg
->from
- f
); /* Added to beginning of region */
325 add
+= t
- nrg
->to
; /* Added to end of region */
329 resv
->adds_in_progress
--;
330 spin_unlock(&resv
->lock
);
336 * Examine the existing reserve map and determine how many
337 * huge pages in the specified range [f, t) are NOT currently
338 * represented. This routine is called before a subsequent
339 * call to region_add that will actually modify the reserve
340 * map to add the specified range [f, t). region_chg does
341 * not change the number of huge pages represented by the
342 * map. However, if the existing regions in the map can not
343 * be expanded to represent the new range, a new file_region
344 * structure is added to the map as a placeholder. This is
345 * so that the subsequent region_add call will have all the
346 * regions it needs and will not fail.
348 * Upon entry, region_chg will also examine the cache of region descriptors
349 * associated with the map. If there are not enough descriptors cached, one
350 * will be allocated for the in progress add operation.
352 * Returns the number of huge pages that need to be added to the existing
353 * reservation map for the range [f, t). This number is greater or equal to
354 * zero. -ENOMEM is returned if a new file_region structure or cache entry
355 * is needed and can not be allocated.
357 static long region_chg(struct resv_map
*resv
, long f
, long t
)
359 struct list_head
*head
= &resv
->regions
;
360 struct file_region
*rg
, *nrg
= NULL
;
364 spin_lock(&resv
->lock
);
366 resv
->adds_in_progress
++;
369 * Check for sufficient descriptors in the cache to accommodate
370 * the number of in progress add operations.
372 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
373 struct file_region
*trg
;
375 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
376 /* Must drop lock to allocate a new descriptor. */
377 resv
->adds_in_progress
--;
378 spin_unlock(&resv
->lock
);
380 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
386 spin_lock(&resv
->lock
);
387 list_add(&trg
->link
, &resv
->region_cache
);
388 resv
->region_cache_count
++;
392 /* Locate the region we are before or in. */
393 list_for_each_entry(rg
, head
, link
)
397 /* If we are below the current region then a new region is required.
398 * Subtle, allocate a new region at the position but make it zero
399 * size such that we can guarantee to record the reservation. */
400 if (&rg
->link
== head
|| t
< rg
->from
) {
402 resv
->adds_in_progress
--;
403 spin_unlock(&resv
->lock
);
404 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
410 INIT_LIST_HEAD(&nrg
->link
);
414 list_add(&nrg
->link
, rg
->link
.prev
);
419 /* Round our left edge to the current segment if it encloses us. */
424 /* Check for and consume any regions we now overlap with. */
425 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
426 if (&rg
->link
== head
)
431 /* We overlap with this area, if it extends further than
432 * us then we must extend ourselves. Account for its
433 * existing reservation. */
438 chg
-= rg
->to
- rg
->from
;
442 spin_unlock(&resv
->lock
);
443 /* We already know we raced and no longer need the new region */
447 spin_unlock(&resv
->lock
);
452 * Abort the in progress add operation. The adds_in_progress field
453 * of the resv_map keeps track of the operations in progress between
454 * calls to region_chg and region_add. Operations are sometimes
455 * aborted after the call to region_chg. In such cases, region_abort
456 * is called to decrement the adds_in_progress counter.
458 * NOTE: The range arguments [f, t) are not needed or used in this
459 * routine. They are kept to make reading the calling code easier as
460 * arguments will match the associated region_chg call.
462 static void region_abort(struct resv_map
*resv
, long f
, long t
)
464 spin_lock(&resv
->lock
);
465 VM_BUG_ON(!resv
->region_cache_count
);
466 resv
->adds_in_progress
--;
467 spin_unlock(&resv
->lock
);
471 * Delete the specified range [f, t) from the reserve map. If the
472 * t parameter is LONG_MAX, this indicates that ALL regions after f
473 * should be deleted. Locate the regions which intersect [f, t)
474 * and either trim, delete or split the existing regions.
476 * Returns the number of huge pages deleted from the reserve map.
477 * In the normal case, the return value is zero or more. In the
478 * case where a region must be split, a new region descriptor must
479 * be allocated. If the allocation fails, -ENOMEM will be returned.
480 * NOTE: If the parameter t == LONG_MAX, then we will never split
481 * a region and possibly return -ENOMEM. Callers specifying
482 * t == LONG_MAX do not need to check for -ENOMEM error.
484 static long region_del(struct resv_map
*resv
, long f
, long t
)
486 struct list_head
*head
= &resv
->regions
;
487 struct file_region
*rg
, *trg
;
488 struct file_region
*nrg
= NULL
;
492 spin_lock(&resv
->lock
);
493 list_for_each_entry_safe(rg
, trg
, head
, link
) {
495 * Skip regions before the range to be deleted. file_region
496 * ranges are normally of the form [from, to). However, there
497 * may be a "placeholder" entry in the map which is of the form
498 * (from, to) with from == to. Check for placeholder entries
499 * at the beginning of the range to be deleted.
501 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
507 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
509 * Check for an entry in the cache before dropping
510 * lock and attempting allocation.
513 resv
->region_cache_count
> resv
->adds_in_progress
) {
514 nrg
= list_first_entry(&resv
->region_cache
,
517 list_del(&nrg
->link
);
518 resv
->region_cache_count
--;
522 spin_unlock(&resv
->lock
);
523 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
531 /* New entry for end of split region */
534 INIT_LIST_HEAD(&nrg
->link
);
536 /* Original entry is trimmed */
539 list_add(&nrg
->link
, &rg
->link
);
544 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
545 del
+= rg
->to
- rg
->from
;
551 if (f
<= rg
->from
) { /* Trim beginning of region */
554 } else { /* Trim end of region */
560 spin_unlock(&resv
->lock
);
566 * A rare out of memory error was encountered which prevented removal of
567 * the reserve map region for a page. The huge page itself was free'ed
568 * and removed from the page cache. This routine will adjust the subpool
569 * usage count, and the global reserve count if needed. By incrementing
570 * these counts, the reserve map entry which could not be deleted will
571 * appear as a "reserved" entry instead of simply dangling with incorrect
574 void hugetlb_fix_reserve_counts(struct inode
*inode
)
576 struct hugepage_subpool
*spool
= subpool_inode(inode
);
579 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
581 struct hstate
*h
= hstate_inode(inode
);
583 hugetlb_acct_memory(h
, 1);
588 * Count and return the number of huge pages in the reserve map
589 * that intersect with the range [f, t).
591 static long region_count(struct resv_map
*resv
, long f
, long t
)
593 struct list_head
*head
= &resv
->regions
;
594 struct file_region
*rg
;
597 spin_lock(&resv
->lock
);
598 /* Locate each segment we overlap with, and count that overlap. */
599 list_for_each_entry(rg
, head
, link
) {
608 seg_from
= max(rg
->from
, f
);
609 seg_to
= min(rg
->to
, t
);
611 chg
+= seg_to
- seg_from
;
613 spin_unlock(&resv
->lock
);
619 * Convert the address within this vma to the page offset within
620 * the mapping, in pagecache page units; huge pages here.
622 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
623 struct vm_area_struct
*vma
, unsigned long address
)
625 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
626 (vma
->vm_pgoff
>> huge_page_order(h
));
629 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
630 unsigned long address
)
632 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
634 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
637 * Return the size of the pages allocated when backing a VMA. In the majority
638 * cases this will be same size as used by the page table entries.
640 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
642 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
643 return vma
->vm_ops
->pagesize(vma
);
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 'strong'
652 * version of this symbol is required.
654 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
656 return vma_kernel_pagesize(vma
);
660 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
661 * bits of the reservation map pointer, which are always clear due to
664 #define HPAGE_RESV_OWNER (1UL << 0)
665 #define HPAGE_RESV_UNMAPPED (1UL << 1)
666 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
669 * These helpers are used to track how many pages are reserved for
670 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
671 * is guaranteed to have their future faults succeed.
673 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
674 * the reserve counters are updated with the hugetlb_lock held. It is safe
675 * to reset the VMA at fork() time as it is not in use yet and there is no
676 * chance of the global counters getting corrupted as a result of the values.
678 * The private mapping reservation is represented in a subtly different
679 * manner to a shared mapping. A shared mapping has a region map associated
680 * with the underlying file, this region map represents the backing file
681 * pages which have ever had a reservation assigned which this persists even
682 * after the page is instantiated. A private mapping has a region map
683 * associated with the original mmap which is attached to all VMAs which
684 * reference it, this region map represents those offsets which have consumed
685 * reservation ie. where pages have been instantiated.
687 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
689 return (unsigned long)vma
->vm_private_data
;
692 static void set_vma_private_data(struct vm_area_struct
*vma
,
695 vma
->vm_private_data
= (void *)value
;
698 struct resv_map
*resv_map_alloc(void)
700 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
701 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
703 if (!resv_map
|| !rg
) {
709 kref_init(&resv_map
->refs
);
710 spin_lock_init(&resv_map
->lock
);
711 INIT_LIST_HEAD(&resv_map
->regions
);
713 resv_map
->adds_in_progress
= 0;
715 INIT_LIST_HEAD(&resv_map
->region_cache
);
716 list_add(&rg
->link
, &resv_map
->region_cache
);
717 resv_map
->region_cache_count
= 1;
722 void resv_map_release(struct kref
*ref
)
724 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
725 struct list_head
*head
= &resv_map
->region_cache
;
726 struct file_region
*rg
, *trg
;
728 /* Clear out any active regions before we release the map. */
729 region_del(resv_map
, 0, LONG_MAX
);
731 /* ... and any entries left in the cache */
732 list_for_each_entry_safe(rg
, trg
, head
, link
) {
737 VM_BUG_ON(resv_map
->adds_in_progress
);
742 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
745 * At inode evict time, i_mapping may not point to the original
746 * address space within the inode. This original address space
747 * contains the pointer to the resv_map. So, always use the
748 * address space embedded within the inode.
749 * The VERY common case is inode->mapping == &inode->i_data but,
750 * this may not be true for device special inodes.
752 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
755 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
757 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
758 if (vma
->vm_flags
& VM_MAYSHARE
) {
759 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
760 struct inode
*inode
= mapping
->host
;
762 return inode_resv_map(inode
);
765 return (struct resv_map
*)(get_vma_private_data(vma
) &
770 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
772 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
773 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
775 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
776 HPAGE_RESV_MASK
) | (unsigned long)map
);
779 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
781 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
782 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
784 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
787 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
789 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
791 return (get_vma_private_data(vma
) & flag
) != 0;
794 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
795 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
797 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
798 if (!(vma
->vm_flags
& VM_MAYSHARE
))
799 vma
->vm_private_data
= (void *)0;
802 /* Returns true if the VMA has associated reserve pages */
803 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
805 if (vma
->vm_flags
& VM_NORESERVE
) {
807 * This address is already reserved by other process(chg == 0),
808 * so, we should decrement reserved count. Without decrementing,
809 * reserve count remains after releasing inode, because this
810 * allocated page will go into page cache and is regarded as
811 * coming from reserved pool in releasing step. Currently, we
812 * don't have any other solution to deal with this situation
813 * properly, so add work-around here.
815 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
821 /* Shared mappings always use reserves */
822 if (vma
->vm_flags
& VM_MAYSHARE
) {
824 * We know VM_NORESERVE is not set. Therefore, there SHOULD
825 * be a region map for all pages. The only situation where
826 * there is no region map is if a hole was punched via
827 * fallocate. In this case, there really are no reverves to
828 * use. This situation is indicated if chg != 0.
837 * Only the process that called mmap() has reserves for
840 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
842 * Like the shared case above, a hole punch or truncate
843 * could have been performed on the private mapping.
844 * Examine the value of chg to determine if reserves
845 * actually exist or were previously consumed.
846 * Very Subtle - The value of chg comes from a previous
847 * call to vma_needs_reserves(). The reserve map for
848 * private mappings has different (opposite) semantics
849 * than that of shared mappings. vma_needs_reserves()
850 * has already taken this difference in semantics into
851 * account. Therefore, the meaning of chg is the same
852 * as in the shared case above. Code could easily be
853 * combined, but keeping it separate draws attention to
854 * subtle differences.
865 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
867 int nid
= page_to_nid(page
);
868 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
869 h
->free_huge_pages
++;
870 h
->free_huge_pages_node
[nid
]++;
873 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
877 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
878 if (!PageHWPoison(page
))
881 * if 'non-isolated free hugepage' not found on the list,
882 * the allocation fails.
884 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
886 list_move(&page
->lru
, &h
->hugepage_activelist
);
887 set_page_refcounted(page
);
888 h
->free_huge_pages
--;
889 h
->free_huge_pages_node
[nid
]--;
893 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
896 unsigned int cpuset_mems_cookie
;
897 struct zonelist
*zonelist
;
900 int node
= NUMA_NO_NODE
;
902 zonelist
= node_zonelist(nid
, gfp_mask
);
905 cpuset_mems_cookie
= read_mems_allowed_begin();
906 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
909 if (!cpuset_zone_allowed(zone
, gfp_mask
))
912 * no need to ask again on the same node. Pool is node rather than
915 if (zone_to_nid(zone
) == node
)
917 node
= zone_to_nid(zone
);
919 page
= dequeue_huge_page_node_exact(h
, node
);
923 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
929 /* Movability of hugepages depends on migration support. */
930 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
932 if (hugepage_movable_supported(h
))
933 return GFP_HIGHUSER_MOVABLE
;
938 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
939 struct vm_area_struct
*vma
,
940 unsigned long address
, int avoid_reserve
,
944 struct mempolicy
*mpol
;
946 nodemask_t
*nodemask
;
950 * A child process with MAP_PRIVATE mappings created by their parent
951 * have no page reserves. This check ensures that reservations are
952 * not "stolen". The child may still get SIGKILLed
954 if (!vma_has_reserves(vma
, chg
) &&
955 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
958 /* If reserves cannot be used, ensure enough pages are in the pool */
959 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
962 gfp_mask
= htlb_alloc_mask(h
);
963 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
964 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
965 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
966 SetPagePrivate(page
);
967 h
->resv_huge_pages
--;
978 * common helper functions for hstate_next_node_to_{alloc|free}.
979 * We may have allocated or freed a huge page based on a different
980 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
981 * be outside of *nodes_allowed. Ensure that we use an allowed
982 * node for alloc or free.
984 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
986 nid
= next_node_in(nid
, *nodes_allowed
);
987 VM_BUG_ON(nid
>= MAX_NUMNODES
);
992 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
994 if (!node_isset(nid
, *nodes_allowed
))
995 nid
= next_node_allowed(nid
, nodes_allowed
);
1000 * returns the previously saved node ["this node"] from which to
1001 * allocate a persistent huge page for the pool and advance the
1002 * next node from which to allocate, handling wrap at end of node
1005 static int hstate_next_node_to_alloc(struct hstate
*h
,
1006 nodemask_t
*nodes_allowed
)
1010 VM_BUG_ON(!nodes_allowed
);
1012 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
1013 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
1019 * helper for free_pool_huge_page() - return the previously saved
1020 * node ["this node"] from which to free a huge page. Advance the
1021 * next node id whether or not we find a free huge page to free so
1022 * that the next attempt to free addresses the next node.
1024 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
1028 VM_BUG_ON(!nodes_allowed
);
1030 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
1031 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
1036 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1037 for (nr_nodes = nodes_weight(*mask); \
1039 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1042 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1043 for (nr_nodes = nodes_weight(*mask); \
1045 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1048 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1049 static void destroy_compound_gigantic_page(struct page
*page
,
1053 int nr_pages
= 1 << order
;
1054 struct page
*p
= page
+ 1;
1056 atomic_set(compound_mapcount_ptr(page
), 0);
1057 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1058 clear_compound_head(p
);
1059 set_page_refcounted(p
);
1062 set_compound_order(page
, 0);
1063 __ClearPageHead(page
);
1066 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1068 free_contig_range(page_to_pfn(page
), 1 << order
);
1071 #ifdef CONFIG_CONTIG_ALLOC
1072 static int __alloc_gigantic_page(unsigned long start_pfn
,
1073 unsigned long nr_pages
, gfp_t gfp_mask
)
1075 unsigned long end_pfn
= start_pfn
+ nr_pages
;
1076 return alloc_contig_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
,
1080 static bool pfn_range_valid_gigantic(struct zone
*z
,
1081 unsigned long start_pfn
, unsigned long nr_pages
)
1083 unsigned long i
, end_pfn
= start_pfn
+ nr_pages
;
1086 for (i
= start_pfn
; i
< end_pfn
; i
++) {
1087 page
= pfn_to_online_page(i
);
1091 if (page_zone(page
) != z
)
1094 if (PageReserved(page
))
1097 if (page_count(page
) > 0)
1107 static bool zone_spans_last_pfn(const struct zone
*zone
,
1108 unsigned long start_pfn
, unsigned long nr_pages
)
1110 unsigned long last_pfn
= start_pfn
+ nr_pages
- 1;
1111 return zone_spans_pfn(zone
, last_pfn
);
1114 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1115 int nid
, nodemask_t
*nodemask
)
1117 unsigned int order
= huge_page_order(h
);
1118 unsigned long nr_pages
= 1 << order
;
1119 unsigned long ret
, pfn
, flags
;
1120 struct zonelist
*zonelist
;
1124 zonelist
= node_zonelist(nid
, gfp_mask
);
1125 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nodemask
) {
1126 spin_lock_irqsave(&zone
->lock
, flags
);
1128 pfn
= ALIGN(zone
->zone_start_pfn
, nr_pages
);
1129 while (zone_spans_last_pfn(zone
, pfn
, nr_pages
)) {
1130 if (pfn_range_valid_gigantic(zone
, pfn
, nr_pages
)) {
1132 * We release the zone lock here because
1133 * alloc_contig_range() will also lock the zone
1134 * at some point. If there's an allocation
1135 * spinning on this lock, it may win the race
1136 * and cause alloc_contig_range() to fail...
1138 spin_unlock_irqrestore(&zone
->lock
, flags
);
1139 ret
= __alloc_gigantic_page(pfn
, nr_pages
, gfp_mask
);
1141 return pfn_to_page(pfn
);
1142 spin_lock_irqsave(&zone
->lock
, flags
);
1147 spin_unlock_irqrestore(&zone
->lock
, flags
);
1153 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1154 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1155 #else /* !CONFIG_CONTIG_ALLOC */
1156 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1157 int nid
, nodemask_t
*nodemask
)
1161 #endif /* CONFIG_CONTIG_ALLOC */
1163 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1164 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1165 int nid
, nodemask_t
*nodemask
)
1169 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1170 static inline void destroy_compound_gigantic_page(struct page
*page
,
1171 unsigned int order
) { }
1174 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1178 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1182 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1183 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1184 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1185 1 << PG_referenced
| 1 << PG_dirty
|
1186 1 << PG_active
| 1 << PG_private
|
1189 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1190 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1191 set_page_refcounted(page
);
1192 if (hstate_is_gigantic(h
)) {
1193 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1194 free_gigantic_page(page
, huge_page_order(h
));
1196 __free_pages(page
, huge_page_order(h
));
1200 struct hstate
*size_to_hstate(unsigned long size
)
1204 for_each_hstate(h
) {
1205 if (huge_page_size(h
) == size
)
1212 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1213 * to hstate->hugepage_activelist.)
1215 * This function can be called for tail pages, but never returns true for them.
1217 bool page_huge_active(struct page
*page
)
1219 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1220 return PageHead(page
) && PagePrivate(&page
[1]);
1223 /* never called for tail page */
1224 static void set_page_huge_active(struct page
*page
)
1226 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1227 SetPagePrivate(&page
[1]);
1230 static void clear_page_huge_active(struct page
*page
)
1232 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1233 ClearPagePrivate(&page
[1]);
1237 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1240 static inline bool PageHugeTemporary(struct page
*page
)
1242 if (!PageHuge(page
))
1245 return (unsigned long)page
[2].mapping
== -1U;
1248 static inline void SetPageHugeTemporary(struct page
*page
)
1250 page
[2].mapping
= (void *)-1U;
1253 static inline void ClearPageHugeTemporary(struct page
*page
)
1255 page
[2].mapping
= NULL
;
1258 void free_huge_page(struct page
*page
)
1261 * Can't pass hstate in here because it is called from the
1262 * compound page destructor.
1264 struct hstate
*h
= page_hstate(page
);
1265 int nid
= page_to_nid(page
);
1266 struct hugepage_subpool
*spool
=
1267 (struct hugepage_subpool
*)page_private(page
);
1268 bool restore_reserve
;
1270 VM_BUG_ON_PAGE(page_count(page
), page
);
1271 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1273 set_page_private(page
, 0);
1274 page
->mapping
= NULL
;
1275 restore_reserve
= PagePrivate(page
);
1276 ClearPagePrivate(page
);
1279 * If PagePrivate() was set on page, page allocation consumed a
1280 * reservation. If the page was associated with a subpool, there
1281 * would have been a page reserved in the subpool before allocation
1282 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1283 * reservtion, do not call hugepage_subpool_put_pages() as this will
1284 * remove the reserved page from the subpool.
1286 if (!restore_reserve
) {
1288 * A return code of zero implies that the subpool will be
1289 * under its minimum size if the reservation is not restored
1290 * after page is free. Therefore, force restore_reserve
1293 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1294 restore_reserve
= true;
1297 spin_lock(&hugetlb_lock
);
1298 clear_page_huge_active(page
);
1299 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1300 pages_per_huge_page(h
), page
);
1301 if (restore_reserve
)
1302 h
->resv_huge_pages
++;
1304 if (PageHugeTemporary(page
)) {
1305 list_del(&page
->lru
);
1306 ClearPageHugeTemporary(page
);
1307 update_and_free_page(h
, page
);
1308 } else if (h
->surplus_huge_pages_node
[nid
]) {
1309 /* remove the page from active list */
1310 list_del(&page
->lru
);
1311 update_and_free_page(h
, page
);
1312 h
->surplus_huge_pages
--;
1313 h
->surplus_huge_pages_node
[nid
]--;
1315 arch_clear_hugepage_flags(page
);
1316 enqueue_huge_page(h
, page
);
1318 spin_unlock(&hugetlb_lock
);
1321 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1323 INIT_LIST_HEAD(&page
->lru
);
1324 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1325 spin_lock(&hugetlb_lock
);
1326 set_hugetlb_cgroup(page
, NULL
);
1328 h
->nr_huge_pages_node
[nid
]++;
1329 spin_unlock(&hugetlb_lock
);
1332 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1335 int nr_pages
= 1 << order
;
1336 struct page
*p
= page
+ 1;
1338 /* we rely on prep_new_huge_page to set the destructor */
1339 set_compound_order(page
, order
);
1340 __ClearPageReserved(page
);
1341 __SetPageHead(page
);
1342 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1344 * For gigantic hugepages allocated through bootmem at
1345 * boot, it's safer to be consistent with the not-gigantic
1346 * hugepages and clear the PG_reserved bit from all tail pages
1347 * too. Otherwse drivers using get_user_pages() to access tail
1348 * pages may get the reference counting wrong if they see
1349 * PG_reserved set on a tail page (despite the head page not
1350 * having PG_reserved set). Enforcing this consistency between
1351 * head and tail pages allows drivers to optimize away a check
1352 * on the head page when they need know if put_page() is needed
1353 * after get_user_pages().
1355 __ClearPageReserved(p
);
1356 set_page_count(p
, 0);
1357 set_compound_head(p
, page
);
1359 atomic_set(compound_mapcount_ptr(page
), -1);
1363 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1364 * transparent huge pages. See the PageTransHuge() documentation for more
1367 int PageHuge(struct page
*page
)
1369 if (!PageCompound(page
))
1372 page
= compound_head(page
);
1373 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1375 EXPORT_SYMBOL_GPL(PageHuge
);
1378 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1379 * normal or transparent huge pages.
1381 int PageHeadHuge(struct page
*page_head
)
1383 if (!PageHead(page_head
))
1386 return get_compound_page_dtor(page_head
) == free_huge_page
;
1389 pgoff_t
__basepage_index(struct page
*page
)
1391 struct page
*page_head
= compound_head(page
);
1392 pgoff_t index
= page_index(page_head
);
1393 unsigned long compound_idx
;
1395 if (!PageHuge(page_head
))
1396 return page_index(page
);
1398 if (compound_order(page_head
) >= MAX_ORDER
)
1399 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1401 compound_idx
= page
- page_head
;
1403 return (index
<< compound_order(page_head
)) + compound_idx
;
1406 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1407 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1408 nodemask_t
*node_alloc_noretry
)
1410 int order
= huge_page_order(h
);
1412 bool alloc_try_hard
= true;
1415 * By default we always try hard to allocate the page with
1416 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1417 * a loop (to adjust global huge page counts) and previous allocation
1418 * failed, do not continue to try hard on the same node. Use the
1419 * node_alloc_noretry bitmap to manage this state information.
1421 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1422 alloc_try_hard
= false;
1423 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1425 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1426 if (nid
== NUMA_NO_NODE
)
1427 nid
= numa_mem_id();
1428 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1430 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1432 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1435 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1436 * indicates an overall state change. Clear bit so that we resume
1437 * normal 'try hard' allocations.
1439 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1440 node_clear(nid
, *node_alloc_noretry
);
1443 * If we tried hard to get a page but failed, set bit so that
1444 * subsequent attempts will not try as hard until there is an
1445 * overall state change.
1447 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1448 node_set(nid
, *node_alloc_noretry
);
1454 * Common helper to allocate a fresh hugetlb page. All specific allocators
1455 * should use this function to get new hugetlb pages
1457 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1458 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1459 nodemask_t
*node_alloc_noretry
)
1463 if (hstate_is_gigantic(h
))
1464 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1466 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1467 nid
, nmask
, node_alloc_noretry
);
1471 if (hstate_is_gigantic(h
))
1472 prep_compound_gigantic_page(page
, huge_page_order(h
));
1473 prep_new_huge_page(h
, page
, page_to_nid(page
));
1479 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1482 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1483 nodemask_t
*node_alloc_noretry
)
1487 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1489 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1490 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1491 node_alloc_noretry
);
1499 put_page(page
); /* free it into the hugepage allocator */
1505 * Free huge page from pool from next node to free.
1506 * Attempt to keep persistent huge pages more or less
1507 * balanced over allowed nodes.
1508 * Called with hugetlb_lock locked.
1510 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1516 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1518 * If we're returning unused surplus pages, only examine
1519 * nodes with surplus pages.
1521 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1522 !list_empty(&h
->hugepage_freelists
[node
])) {
1524 list_entry(h
->hugepage_freelists
[node
].next
,
1526 list_del(&page
->lru
);
1527 h
->free_huge_pages
--;
1528 h
->free_huge_pages_node
[node
]--;
1530 h
->surplus_huge_pages
--;
1531 h
->surplus_huge_pages_node
[node
]--;
1533 update_and_free_page(h
, page
);
1543 * Dissolve a given free hugepage into free buddy pages. This function does
1544 * nothing for in-use hugepages and non-hugepages.
1545 * This function returns values like below:
1547 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1548 * (allocated or reserved.)
1549 * 0: successfully dissolved free hugepages or the page is not a
1550 * hugepage (considered as already dissolved)
1552 int dissolve_free_huge_page(struct page
*page
)
1556 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1557 if (!PageHuge(page
))
1560 spin_lock(&hugetlb_lock
);
1561 if (!PageHuge(page
)) {
1566 if (!page_count(page
)) {
1567 struct page
*head
= compound_head(page
);
1568 struct hstate
*h
= page_hstate(head
);
1569 int nid
= page_to_nid(head
);
1570 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1573 * Move PageHWPoison flag from head page to the raw error page,
1574 * which makes any subpages rather than the error page reusable.
1576 if (PageHWPoison(head
) && page
!= head
) {
1577 SetPageHWPoison(page
);
1578 ClearPageHWPoison(head
);
1580 list_del(&head
->lru
);
1581 h
->free_huge_pages
--;
1582 h
->free_huge_pages_node
[nid
]--;
1583 h
->max_huge_pages
--;
1584 update_and_free_page(h
, head
);
1588 spin_unlock(&hugetlb_lock
);
1593 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1594 * make specified memory blocks removable from the system.
1595 * Note that this will dissolve a free gigantic hugepage completely, if any
1596 * part of it lies within the given range.
1597 * Also note that if dissolve_free_huge_page() returns with an error, all
1598 * free hugepages that were dissolved before that error are lost.
1600 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1606 if (!hugepages_supported())
1609 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1610 page
= pfn_to_page(pfn
);
1611 rc
= dissolve_free_huge_page(page
);
1620 * Allocates a fresh surplus page from the page allocator.
1622 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1623 int nid
, nodemask_t
*nmask
)
1625 struct page
*page
= NULL
;
1627 if (hstate_is_gigantic(h
))
1630 spin_lock(&hugetlb_lock
);
1631 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1633 spin_unlock(&hugetlb_lock
);
1635 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1639 spin_lock(&hugetlb_lock
);
1641 * We could have raced with the pool size change.
1642 * Double check that and simply deallocate the new page
1643 * if we would end up overcommiting the surpluses. Abuse
1644 * temporary page to workaround the nasty free_huge_page
1647 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1648 SetPageHugeTemporary(page
);
1649 spin_unlock(&hugetlb_lock
);
1653 h
->surplus_huge_pages
++;
1654 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1658 spin_unlock(&hugetlb_lock
);
1663 struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1664 int nid
, nodemask_t
*nmask
)
1668 if (hstate_is_gigantic(h
))
1671 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1676 * We do not account these pages as surplus because they are only
1677 * temporary and will be released properly on the last reference
1679 SetPageHugeTemporary(page
);
1685 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1688 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1689 struct vm_area_struct
*vma
, unsigned long addr
)
1692 struct mempolicy
*mpol
;
1693 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1695 nodemask_t
*nodemask
;
1697 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1698 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1699 mpol_cond_put(mpol
);
1704 /* page migration callback function */
1705 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1707 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1708 struct page
*page
= NULL
;
1710 if (nid
!= NUMA_NO_NODE
)
1711 gfp_mask
|= __GFP_THISNODE
;
1713 spin_lock(&hugetlb_lock
);
1714 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1715 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1716 spin_unlock(&hugetlb_lock
);
1719 page
= alloc_migrate_huge_page(h
, gfp_mask
, nid
, NULL
);
1724 /* page migration callback function */
1725 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1728 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1730 spin_lock(&hugetlb_lock
);
1731 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1734 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1736 spin_unlock(&hugetlb_lock
);
1740 spin_unlock(&hugetlb_lock
);
1742 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1745 /* mempolicy aware migration callback */
1746 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
1747 unsigned long address
)
1749 struct mempolicy
*mpol
;
1750 nodemask_t
*nodemask
;
1755 gfp_mask
= htlb_alloc_mask(h
);
1756 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1757 page
= alloc_huge_page_nodemask(h
, node
, nodemask
);
1758 mpol_cond_put(mpol
);
1764 * Increase the hugetlb pool such that it can accommodate a reservation
1767 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1769 struct list_head surplus_list
;
1770 struct page
*page
, *tmp
;
1772 int needed
, allocated
;
1773 bool alloc_ok
= true;
1775 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1777 h
->resv_huge_pages
+= delta
;
1782 INIT_LIST_HEAD(&surplus_list
);
1786 spin_unlock(&hugetlb_lock
);
1787 for (i
= 0; i
< needed
; i
++) {
1788 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
1789 NUMA_NO_NODE
, NULL
);
1794 list_add(&page
->lru
, &surplus_list
);
1800 * After retaking hugetlb_lock, we need to recalculate 'needed'
1801 * because either resv_huge_pages or free_huge_pages may have changed.
1803 spin_lock(&hugetlb_lock
);
1804 needed
= (h
->resv_huge_pages
+ delta
) -
1805 (h
->free_huge_pages
+ allocated
);
1810 * We were not able to allocate enough pages to
1811 * satisfy the entire reservation so we free what
1812 * we've allocated so far.
1817 * The surplus_list now contains _at_least_ the number of extra pages
1818 * needed to accommodate the reservation. Add the appropriate number
1819 * of pages to the hugetlb pool and free the extras back to the buddy
1820 * allocator. Commit the entire reservation here to prevent another
1821 * process from stealing the pages as they are added to the pool but
1822 * before they are reserved.
1824 needed
+= allocated
;
1825 h
->resv_huge_pages
+= delta
;
1828 /* Free the needed pages to the hugetlb pool */
1829 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1833 * This page is now managed by the hugetlb allocator and has
1834 * no users -- drop the buddy allocator's reference.
1836 put_page_testzero(page
);
1837 VM_BUG_ON_PAGE(page_count(page
), page
);
1838 enqueue_huge_page(h
, page
);
1841 spin_unlock(&hugetlb_lock
);
1843 /* Free unnecessary surplus pages to the buddy allocator */
1844 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1846 spin_lock(&hugetlb_lock
);
1852 * This routine has two main purposes:
1853 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1854 * in unused_resv_pages. This corresponds to the prior adjustments made
1855 * to the associated reservation map.
1856 * 2) Free any unused surplus pages that may have been allocated to satisfy
1857 * the reservation. As many as unused_resv_pages may be freed.
1859 * Called with hugetlb_lock held. However, the lock could be dropped (and
1860 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1861 * we must make sure nobody else can claim pages we are in the process of
1862 * freeing. Do this by ensuring resv_huge_page always is greater than the
1863 * number of huge pages we plan to free when dropping the lock.
1865 static void return_unused_surplus_pages(struct hstate
*h
,
1866 unsigned long unused_resv_pages
)
1868 unsigned long nr_pages
;
1870 /* Cannot return gigantic pages currently */
1871 if (hstate_is_gigantic(h
))
1875 * Part (or even all) of the reservation could have been backed
1876 * by pre-allocated pages. Only free surplus pages.
1878 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1881 * We want to release as many surplus pages as possible, spread
1882 * evenly across all nodes with memory. Iterate across these nodes
1883 * until we can no longer free unreserved surplus pages. This occurs
1884 * when the nodes with surplus pages have no free pages.
1885 * free_pool_huge_page() will balance the the freed pages across the
1886 * on-line nodes with memory and will handle the hstate accounting.
1888 * Note that we decrement resv_huge_pages as we free the pages. If
1889 * we drop the lock, resv_huge_pages will still be sufficiently large
1890 * to cover subsequent pages we may free.
1892 while (nr_pages
--) {
1893 h
->resv_huge_pages
--;
1894 unused_resv_pages
--;
1895 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1897 cond_resched_lock(&hugetlb_lock
);
1901 /* Fully uncommit the reservation */
1902 h
->resv_huge_pages
-= unused_resv_pages
;
1907 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1908 * are used by the huge page allocation routines to manage reservations.
1910 * vma_needs_reservation is called to determine if the huge page at addr
1911 * within the vma has an associated reservation. If a reservation is
1912 * needed, the value 1 is returned. The caller is then responsible for
1913 * managing the global reservation and subpool usage counts. After
1914 * the huge page has been allocated, vma_commit_reservation is called
1915 * to add the page to the reservation map. If the page allocation fails,
1916 * the reservation must be ended instead of committed. vma_end_reservation
1917 * is called in such cases.
1919 * In the normal case, vma_commit_reservation returns the same value
1920 * as the preceding vma_needs_reservation call. The only time this
1921 * is not the case is if a reserve map was changed between calls. It
1922 * is the responsibility of the caller to notice the difference and
1923 * take appropriate action.
1925 * vma_add_reservation is used in error paths where a reservation must
1926 * be restored when a newly allocated huge page must be freed. It is
1927 * to be called after calling vma_needs_reservation to determine if a
1928 * reservation exists.
1930 enum vma_resv_mode
{
1936 static long __vma_reservation_common(struct hstate
*h
,
1937 struct vm_area_struct
*vma
, unsigned long addr
,
1938 enum vma_resv_mode mode
)
1940 struct resv_map
*resv
;
1944 resv
= vma_resv_map(vma
);
1948 idx
= vma_hugecache_offset(h
, vma
, addr
);
1950 case VMA_NEEDS_RESV
:
1951 ret
= region_chg(resv
, idx
, idx
+ 1);
1953 case VMA_COMMIT_RESV
:
1954 ret
= region_add(resv
, idx
, idx
+ 1);
1957 region_abort(resv
, idx
, idx
+ 1);
1961 if (vma
->vm_flags
& VM_MAYSHARE
)
1962 ret
= region_add(resv
, idx
, idx
+ 1);
1964 region_abort(resv
, idx
, idx
+ 1);
1965 ret
= region_del(resv
, idx
, idx
+ 1);
1972 if (vma
->vm_flags
& VM_MAYSHARE
)
1974 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
1976 * In most cases, reserves always exist for private mappings.
1977 * However, a file associated with mapping could have been
1978 * hole punched or truncated after reserves were consumed.
1979 * As subsequent fault on such a range will not use reserves.
1980 * Subtle - The reserve map for private mappings has the
1981 * opposite meaning than that of shared mappings. If NO
1982 * entry is in the reserve map, it means a reservation exists.
1983 * If an entry exists in the reserve map, it means the
1984 * reservation has already been consumed. As a result, the
1985 * return value of this routine is the opposite of the
1986 * value returned from reserve map manipulation routines above.
1994 return ret
< 0 ? ret
: 0;
1997 static long vma_needs_reservation(struct hstate
*h
,
1998 struct vm_area_struct
*vma
, unsigned long addr
)
2000 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
2003 static long vma_commit_reservation(struct hstate
*h
,
2004 struct vm_area_struct
*vma
, unsigned long addr
)
2006 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
2009 static void vma_end_reservation(struct hstate
*h
,
2010 struct vm_area_struct
*vma
, unsigned long addr
)
2012 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
2015 static long vma_add_reservation(struct hstate
*h
,
2016 struct vm_area_struct
*vma
, unsigned long addr
)
2018 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
2022 * This routine is called to restore a reservation on error paths. In the
2023 * specific error paths, a huge page was allocated (via alloc_huge_page)
2024 * and is about to be freed. If a reservation for the page existed,
2025 * alloc_huge_page would have consumed the reservation and set PagePrivate
2026 * in the newly allocated page. When the page is freed via free_huge_page,
2027 * the global reservation count will be incremented if PagePrivate is set.
2028 * However, free_huge_page can not adjust the reserve map. Adjust the
2029 * reserve map here to be consistent with global reserve count adjustments
2030 * to be made by free_huge_page.
2032 static void restore_reserve_on_error(struct hstate
*h
,
2033 struct vm_area_struct
*vma
, unsigned long address
,
2036 if (unlikely(PagePrivate(page
))) {
2037 long rc
= vma_needs_reservation(h
, vma
, address
);
2039 if (unlikely(rc
< 0)) {
2041 * Rare out of memory condition in reserve map
2042 * manipulation. Clear PagePrivate so that
2043 * global reserve count will not be incremented
2044 * by free_huge_page. This will make it appear
2045 * as though the reservation for this page was
2046 * consumed. This may prevent the task from
2047 * faulting in the page at a later time. This
2048 * is better than inconsistent global huge page
2049 * accounting of reserve counts.
2051 ClearPagePrivate(page
);
2053 rc
= vma_add_reservation(h
, vma
, address
);
2054 if (unlikely(rc
< 0))
2056 * See above comment about rare out of
2059 ClearPagePrivate(page
);
2061 vma_end_reservation(h
, vma
, address
);
2065 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2066 unsigned long addr
, int avoid_reserve
)
2068 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2069 struct hstate
*h
= hstate_vma(vma
);
2071 long map_chg
, map_commit
;
2074 struct hugetlb_cgroup
*h_cg
;
2076 idx
= hstate_index(h
);
2078 * Examine the region/reserve map to determine if the process
2079 * has a reservation for the page to be allocated. A return
2080 * code of zero indicates a reservation exists (no change).
2082 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2084 return ERR_PTR(-ENOMEM
);
2087 * Processes that did not create the mapping will have no
2088 * reserves as indicated by the region/reserve map. Check
2089 * that the allocation will not exceed the subpool limit.
2090 * Allocations for MAP_NORESERVE mappings also need to be
2091 * checked against any subpool limit.
2093 if (map_chg
|| avoid_reserve
) {
2094 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2096 vma_end_reservation(h
, vma
, addr
);
2097 return ERR_PTR(-ENOSPC
);
2101 * Even though there was no reservation in the region/reserve
2102 * map, there could be reservations associated with the
2103 * subpool that can be used. This would be indicated if the
2104 * return value of hugepage_subpool_get_pages() is zero.
2105 * However, if avoid_reserve is specified we still avoid even
2106 * the subpool reservations.
2112 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2114 goto out_subpool_put
;
2116 spin_lock(&hugetlb_lock
);
2118 * glb_chg is passed to indicate whether or not a page must be taken
2119 * from the global free pool (global change). gbl_chg == 0 indicates
2120 * a reservation exists for the allocation.
2122 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2124 spin_unlock(&hugetlb_lock
);
2125 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2127 goto out_uncharge_cgroup
;
2128 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2129 SetPagePrivate(page
);
2130 h
->resv_huge_pages
--;
2132 spin_lock(&hugetlb_lock
);
2133 list_move(&page
->lru
, &h
->hugepage_activelist
);
2136 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2137 spin_unlock(&hugetlb_lock
);
2139 set_page_private(page
, (unsigned long)spool
);
2141 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2142 if (unlikely(map_chg
> map_commit
)) {
2144 * The page was added to the reservation map between
2145 * vma_needs_reservation and vma_commit_reservation.
2146 * This indicates a race with hugetlb_reserve_pages.
2147 * Adjust for the subpool count incremented above AND
2148 * in hugetlb_reserve_pages for the same page. Also,
2149 * the reservation count added in hugetlb_reserve_pages
2150 * no longer applies.
2154 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2155 hugetlb_acct_memory(h
, -rsv_adjust
);
2159 out_uncharge_cgroup
:
2160 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2162 if (map_chg
|| avoid_reserve
)
2163 hugepage_subpool_put_pages(spool
, 1);
2164 vma_end_reservation(h
, vma
, addr
);
2165 return ERR_PTR(-ENOSPC
);
2168 int alloc_bootmem_huge_page(struct hstate
*h
)
2169 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2170 int __alloc_bootmem_huge_page(struct hstate
*h
)
2172 struct huge_bootmem_page
*m
;
2175 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2178 addr
= memblock_alloc_try_nid_raw(
2179 huge_page_size(h
), huge_page_size(h
),
2180 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2183 * Use the beginning of the huge page to store the
2184 * huge_bootmem_page struct (until gather_bootmem
2185 * puts them into the mem_map).
2194 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2195 /* Put them into a private list first because mem_map is not up yet */
2196 INIT_LIST_HEAD(&m
->list
);
2197 list_add(&m
->list
, &huge_boot_pages
);
2202 static void __init
prep_compound_huge_page(struct page
*page
,
2205 if (unlikely(order
> (MAX_ORDER
- 1)))
2206 prep_compound_gigantic_page(page
, order
);
2208 prep_compound_page(page
, order
);
2211 /* Put bootmem huge pages into the standard lists after mem_map is up */
2212 static void __init
gather_bootmem_prealloc(void)
2214 struct huge_bootmem_page
*m
;
2216 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2217 struct page
*page
= virt_to_page(m
);
2218 struct hstate
*h
= m
->hstate
;
2220 WARN_ON(page_count(page
) != 1);
2221 prep_compound_huge_page(page
, h
->order
);
2222 WARN_ON(PageReserved(page
));
2223 prep_new_huge_page(h
, page
, page_to_nid(page
));
2224 put_page(page
); /* free it into the hugepage allocator */
2227 * If we had gigantic hugepages allocated at boot time, we need
2228 * to restore the 'stolen' pages to totalram_pages in order to
2229 * fix confusing memory reports from free(1) and another
2230 * side-effects, like CommitLimit going negative.
2232 if (hstate_is_gigantic(h
))
2233 adjust_managed_page_count(page
, 1 << h
->order
);
2238 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2241 nodemask_t
*node_alloc_noretry
;
2243 if (!hstate_is_gigantic(h
)) {
2245 * Bit mask controlling how hard we retry per-node allocations.
2246 * Ignore errors as lower level routines can deal with
2247 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2248 * time, we are likely in bigger trouble.
2250 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2253 /* allocations done at boot time */
2254 node_alloc_noretry
= NULL
;
2257 /* bit mask controlling how hard we retry per-node allocations */
2258 if (node_alloc_noretry
)
2259 nodes_clear(*node_alloc_noretry
);
2261 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2262 if (hstate_is_gigantic(h
)) {
2263 if (!alloc_bootmem_huge_page(h
))
2265 } else if (!alloc_pool_huge_page(h
,
2266 &node_states
[N_MEMORY
],
2267 node_alloc_noretry
))
2271 if (i
< h
->max_huge_pages
) {
2274 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2275 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2276 h
->max_huge_pages
, buf
, i
);
2277 h
->max_huge_pages
= i
;
2280 kfree(node_alloc_noretry
);
2283 static void __init
hugetlb_init_hstates(void)
2287 for_each_hstate(h
) {
2288 if (minimum_order
> huge_page_order(h
))
2289 minimum_order
= huge_page_order(h
);
2291 /* oversize hugepages were init'ed in early boot */
2292 if (!hstate_is_gigantic(h
))
2293 hugetlb_hstate_alloc_pages(h
);
2295 VM_BUG_ON(minimum_order
== UINT_MAX
);
2298 static void __init
report_hugepages(void)
2302 for_each_hstate(h
) {
2305 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2306 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2307 buf
, h
->free_huge_pages
);
2311 #ifdef CONFIG_HIGHMEM
2312 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2313 nodemask_t
*nodes_allowed
)
2317 if (hstate_is_gigantic(h
))
2320 for_each_node_mask(i
, *nodes_allowed
) {
2321 struct page
*page
, *next
;
2322 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2323 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2324 if (count
>= h
->nr_huge_pages
)
2326 if (PageHighMem(page
))
2328 list_del(&page
->lru
);
2329 update_and_free_page(h
, page
);
2330 h
->free_huge_pages
--;
2331 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2336 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2337 nodemask_t
*nodes_allowed
)
2343 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2344 * balanced by operating on them in a round-robin fashion.
2345 * Returns 1 if an adjustment was made.
2347 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2352 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2355 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2356 if (h
->surplus_huge_pages_node
[node
])
2360 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2361 if (h
->surplus_huge_pages_node
[node
] <
2362 h
->nr_huge_pages_node
[node
])
2369 h
->surplus_huge_pages
+= delta
;
2370 h
->surplus_huge_pages_node
[node
] += delta
;
2374 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2375 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2376 nodemask_t
*nodes_allowed
)
2378 unsigned long min_count
, ret
;
2379 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2382 * Bit mask controlling how hard we retry per-node allocations.
2383 * If we can not allocate the bit mask, do not attempt to allocate
2384 * the requested huge pages.
2386 if (node_alloc_noretry
)
2387 nodes_clear(*node_alloc_noretry
);
2391 spin_lock(&hugetlb_lock
);
2394 * Check for a node specific request.
2395 * Changing node specific huge page count may require a corresponding
2396 * change to the global count. In any case, the passed node mask
2397 * (nodes_allowed) will restrict alloc/free to the specified node.
2399 if (nid
!= NUMA_NO_NODE
) {
2400 unsigned long old_count
= count
;
2402 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2404 * User may have specified a large count value which caused the
2405 * above calculation to overflow. In this case, they wanted
2406 * to allocate as many huge pages as possible. Set count to
2407 * largest possible value to align with their intention.
2409 if (count
< old_count
)
2414 * Gigantic pages runtime allocation depend on the capability for large
2415 * page range allocation.
2416 * If the system does not provide this feature, return an error when
2417 * the user tries to allocate gigantic pages but let the user free the
2418 * boottime allocated gigantic pages.
2420 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2421 if (count
> persistent_huge_pages(h
)) {
2422 spin_unlock(&hugetlb_lock
);
2423 NODEMASK_FREE(node_alloc_noretry
);
2426 /* Fall through to decrease pool */
2430 * Increase the pool size
2431 * First take pages out of surplus state. Then make up the
2432 * remaining difference by allocating fresh huge pages.
2434 * We might race with alloc_surplus_huge_page() here and be unable
2435 * to convert a surplus huge page to a normal huge page. That is
2436 * not critical, though, it just means the overall size of the
2437 * pool might be one hugepage larger than it needs to be, but
2438 * within all the constraints specified by the sysctls.
2440 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2441 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2445 while (count
> persistent_huge_pages(h
)) {
2447 * If this allocation races such that we no longer need the
2448 * page, free_huge_page will handle it by freeing the page
2449 * and reducing the surplus.
2451 spin_unlock(&hugetlb_lock
);
2453 /* yield cpu to avoid soft lockup */
2456 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2457 node_alloc_noretry
);
2458 spin_lock(&hugetlb_lock
);
2462 /* Bail for signals. Probably ctrl-c from user */
2463 if (signal_pending(current
))
2468 * Decrease the pool size
2469 * First return free pages to the buddy allocator (being careful
2470 * to keep enough around to satisfy reservations). Then place
2471 * pages into surplus state as needed so the pool will shrink
2472 * to the desired size as pages become free.
2474 * By placing pages into the surplus state independent of the
2475 * overcommit value, we are allowing the surplus pool size to
2476 * exceed overcommit. There are few sane options here. Since
2477 * alloc_surplus_huge_page() is checking the global counter,
2478 * though, we'll note that we're not allowed to exceed surplus
2479 * and won't grow the pool anywhere else. Not until one of the
2480 * sysctls are changed, or the surplus pages go out of use.
2482 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2483 min_count
= max(count
, min_count
);
2484 try_to_free_low(h
, min_count
, nodes_allowed
);
2485 while (min_count
< persistent_huge_pages(h
)) {
2486 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2488 cond_resched_lock(&hugetlb_lock
);
2490 while (count
< persistent_huge_pages(h
)) {
2491 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2495 h
->max_huge_pages
= persistent_huge_pages(h
);
2496 spin_unlock(&hugetlb_lock
);
2498 NODEMASK_FREE(node_alloc_noretry
);
2503 #define HSTATE_ATTR_RO(_name) \
2504 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2506 #define HSTATE_ATTR(_name) \
2507 static struct kobj_attribute _name##_attr = \
2508 __ATTR(_name, 0644, _name##_show, _name##_store)
2510 static struct kobject
*hugepages_kobj
;
2511 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2513 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2515 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2519 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2520 if (hstate_kobjs
[i
] == kobj
) {
2522 *nidp
= NUMA_NO_NODE
;
2526 return kobj_to_node_hstate(kobj
, nidp
);
2529 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2530 struct kobj_attribute
*attr
, char *buf
)
2533 unsigned long nr_huge_pages
;
2536 h
= kobj_to_hstate(kobj
, &nid
);
2537 if (nid
== NUMA_NO_NODE
)
2538 nr_huge_pages
= h
->nr_huge_pages
;
2540 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2542 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2545 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2546 struct hstate
*h
, int nid
,
2547 unsigned long count
, size_t len
)
2550 nodemask_t nodes_allowed
, *n_mask
;
2552 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2555 if (nid
== NUMA_NO_NODE
) {
2557 * global hstate attribute
2559 if (!(obey_mempolicy
&&
2560 init_nodemask_of_mempolicy(&nodes_allowed
)))
2561 n_mask
= &node_states
[N_MEMORY
];
2563 n_mask
= &nodes_allowed
;
2566 * Node specific request. count adjustment happens in
2567 * set_max_huge_pages() after acquiring hugetlb_lock.
2569 init_nodemask_of_node(&nodes_allowed
, nid
);
2570 n_mask
= &nodes_allowed
;
2573 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2575 return err
? err
: len
;
2578 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2579 struct kobject
*kobj
, const char *buf
,
2583 unsigned long count
;
2587 err
= kstrtoul(buf
, 10, &count
);
2591 h
= kobj_to_hstate(kobj
, &nid
);
2592 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2595 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2596 struct kobj_attribute
*attr
, char *buf
)
2598 return nr_hugepages_show_common(kobj
, attr
, buf
);
2601 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2602 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2604 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2606 HSTATE_ATTR(nr_hugepages
);
2611 * hstate attribute for optionally mempolicy-based constraint on persistent
2612 * huge page alloc/free.
2614 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2615 struct kobj_attribute
*attr
, char *buf
)
2617 return nr_hugepages_show_common(kobj
, attr
, buf
);
2620 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2621 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2623 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2625 HSTATE_ATTR(nr_hugepages_mempolicy
);
2629 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2630 struct kobj_attribute
*attr
, char *buf
)
2632 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2633 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2636 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2637 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2640 unsigned long input
;
2641 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2643 if (hstate_is_gigantic(h
))
2646 err
= kstrtoul(buf
, 10, &input
);
2650 spin_lock(&hugetlb_lock
);
2651 h
->nr_overcommit_huge_pages
= input
;
2652 spin_unlock(&hugetlb_lock
);
2656 HSTATE_ATTR(nr_overcommit_hugepages
);
2658 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2659 struct kobj_attribute
*attr
, char *buf
)
2662 unsigned long free_huge_pages
;
2665 h
= kobj_to_hstate(kobj
, &nid
);
2666 if (nid
== NUMA_NO_NODE
)
2667 free_huge_pages
= h
->free_huge_pages
;
2669 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2671 return sprintf(buf
, "%lu\n", free_huge_pages
);
2673 HSTATE_ATTR_RO(free_hugepages
);
2675 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2676 struct kobj_attribute
*attr
, char *buf
)
2678 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2679 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2681 HSTATE_ATTR_RO(resv_hugepages
);
2683 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2684 struct kobj_attribute
*attr
, char *buf
)
2687 unsigned long surplus_huge_pages
;
2690 h
= kobj_to_hstate(kobj
, &nid
);
2691 if (nid
== NUMA_NO_NODE
)
2692 surplus_huge_pages
= h
->surplus_huge_pages
;
2694 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2696 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2698 HSTATE_ATTR_RO(surplus_hugepages
);
2700 static struct attribute
*hstate_attrs
[] = {
2701 &nr_hugepages_attr
.attr
,
2702 &nr_overcommit_hugepages_attr
.attr
,
2703 &free_hugepages_attr
.attr
,
2704 &resv_hugepages_attr
.attr
,
2705 &surplus_hugepages_attr
.attr
,
2707 &nr_hugepages_mempolicy_attr
.attr
,
2712 static const struct attribute_group hstate_attr_group
= {
2713 .attrs
= hstate_attrs
,
2716 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2717 struct kobject
**hstate_kobjs
,
2718 const struct attribute_group
*hstate_attr_group
)
2721 int hi
= hstate_index(h
);
2723 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2724 if (!hstate_kobjs
[hi
])
2727 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2729 kobject_put(hstate_kobjs
[hi
]);
2734 static void __init
hugetlb_sysfs_init(void)
2739 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2740 if (!hugepages_kobj
)
2743 for_each_hstate(h
) {
2744 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2745 hstate_kobjs
, &hstate_attr_group
);
2747 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2754 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2755 * with node devices in node_devices[] using a parallel array. The array
2756 * index of a node device or _hstate == node id.
2757 * This is here to avoid any static dependency of the node device driver, in
2758 * the base kernel, on the hugetlb module.
2760 struct node_hstate
{
2761 struct kobject
*hugepages_kobj
;
2762 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2764 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2767 * A subset of global hstate attributes for node devices
2769 static struct attribute
*per_node_hstate_attrs
[] = {
2770 &nr_hugepages_attr
.attr
,
2771 &free_hugepages_attr
.attr
,
2772 &surplus_hugepages_attr
.attr
,
2776 static const struct attribute_group per_node_hstate_attr_group
= {
2777 .attrs
= per_node_hstate_attrs
,
2781 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2782 * Returns node id via non-NULL nidp.
2784 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2788 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2789 struct node_hstate
*nhs
= &node_hstates
[nid
];
2791 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2792 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2804 * Unregister hstate attributes from a single node device.
2805 * No-op if no hstate attributes attached.
2807 static void hugetlb_unregister_node(struct node
*node
)
2810 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2812 if (!nhs
->hugepages_kobj
)
2813 return; /* no hstate attributes */
2815 for_each_hstate(h
) {
2816 int idx
= hstate_index(h
);
2817 if (nhs
->hstate_kobjs
[idx
]) {
2818 kobject_put(nhs
->hstate_kobjs
[idx
]);
2819 nhs
->hstate_kobjs
[idx
] = NULL
;
2823 kobject_put(nhs
->hugepages_kobj
);
2824 nhs
->hugepages_kobj
= NULL
;
2829 * Register hstate attributes for a single node device.
2830 * No-op if attributes already registered.
2832 static void hugetlb_register_node(struct node
*node
)
2835 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2838 if (nhs
->hugepages_kobj
)
2839 return; /* already allocated */
2841 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2843 if (!nhs
->hugepages_kobj
)
2846 for_each_hstate(h
) {
2847 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2849 &per_node_hstate_attr_group
);
2851 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2852 h
->name
, node
->dev
.id
);
2853 hugetlb_unregister_node(node
);
2860 * hugetlb init time: register hstate attributes for all registered node
2861 * devices of nodes that have memory. All on-line nodes should have
2862 * registered their associated device by this time.
2864 static void __init
hugetlb_register_all_nodes(void)
2868 for_each_node_state(nid
, N_MEMORY
) {
2869 struct node
*node
= node_devices
[nid
];
2870 if (node
->dev
.id
== nid
)
2871 hugetlb_register_node(node
);
2875 * Let the node device driver know we're here so it can
2876 * [un]register hstate attributes on node hotplug.
2878 register_hugetlbfs_with_node(hugetlb_register_node
,
2879 hugetlb_unregister_node
);
2881 #else /* !CONFIG_NUMA */
2883 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2891 static void hugetlb_register_all_nodes(void) { }
2895 static int __init
hugetlb_init(void)
2899 if (!hugepages_supported())
2902 if (!size_to_hstate(default_hstate_size
)) {
2903 if (default_hstate_size
!= 0) {
2904 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
2905 default_hstate_size
, HPAGE_SIZE
);
2908 default_hstate_size
= HPAGE_SIZE
;
2909 if (!size_to_hstate(default_hstate_size
))
2910 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2912 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2913 if (default_hstate_max_huge_pages
) {
2914 if (!default_hstate
.max_huge_pages
)
2915 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2918 hugetlb_init_hstates();
2919 gather_bootmem_prealloc();
2922 hugetlb_sysfs_init();
2923 hugetlb_register_all_nodes();
2924 hugetlb_cgroup_file_init();
2927 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2929 num_fault_mutexes
= 1;
2931 hugetlb_fault_mutex_table
=
2932 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
2934 BUG_ON(!hugetlb_fault_mutex_table
);
2936 for (i
= 0; i
< num_fault_mutexes
; i
++)
2937 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2940 subsys_initcall(hugetlb_init
);
2942 /* Should be called on processing a hugepagesz=... option */
2943 void __init
hugetlb_bad_size(void)
2945 parsed_valid_hugepagesz
= false;
2948 void __init
hugetlb_add_hstate(unsigned int order
)
2953 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2954 pr_warn("hugepagesz= specified twice, ignoring\n");
2957 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2959 h
= &hstates
[hugetlb_max_hstate
++];
2961 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2962 h
->nr_huge_pages
= 0;
2963 h
->free_huge_pages
= 0;
2964 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2965 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2966 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2967 h
->next_nid_to_alloc
= first_memory_node
;
2968 h
->next_nid_to_free
= first_memory_node
;
2969 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2970 huge_page_size(h
)/1024);
2975 static int __init
hugetlb_nrpages_setup(char *s
)
2978 static unsigned long *last_mhp
;
2980 if (!parsed_valid_hugepagesz
) {
2981 pr_warn("hugepages = %s preceded by "
2982 "an unsupported hugepagesz, ignoring\n", s
);
2983 parsed_valid_hugepagesz
= true;
2987 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2988 * so this hugepages= parameter goes to the "default hstate".
2990 else if (!hugetlb_max_hstate
)
2991 mhp
= &default_hstate_max_huge_pages
;
2993 mhp
= &parsed_hstate
->max_huge_pages
;
2995 if (mhp
== last_mhp
) {
2996 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
3000 if (sscanf(s
, "%lu", mhp
) <= 0)
3004 * Global state is always initialized later in hugetlb_init.
3005 * But we need to allocate >= MAX_ORDER hstates here early to still
3006 * use the bootmem allocator.
3008 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
3009 hugetlb_hstate_alloc_pages(parsed_hstate
);
3015 __setup("hugepages=", hugetlb_nrpages_setup
);
3017 static int __init
hugetlb_default_setup(char *s
)
3019 default_hstate_size
= memparse(s
, &s
);
3022 __setup("default_hugepagesz=", hugetlb_default_setup
);
3024 static unsigned int cpuset_mems_nr(unsigned int *array
)
3027 unsigned int nr
= 0;
3029 for_each_node_mask(node
, cpuset_current_mems_allowed
)
3035 #ifdef CONFIG_SYSCTL
3036 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
3037 struct ctl_table
*table
, int write
,
3038 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3040 struct hstate
*h
= &default_hstate
;
3041 unsigned long tmp
= h
->max_huge_pages
;
3044 if (!hugepages_supported())
3048 table
->maxlen
= sizeof(unsigned long);
3049 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3054 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
3055 NUMA_NO_NODE
, tmp
, *length
);
3060 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
3061 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3064 return hugetlb_sysctl_handler_common(false, table
, write
,
3065 buffer
, length
, ppos
);
3069 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3070 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3072 return hugetlb_sysctl_handler_common(true, table
, write
,
3073 buffer
, length
, ppos
);
3075 #endif /* CONFIG_NUMA */
3077 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3078 void __user
*buffer
,
3079 size_t *length
, loff_t
*ppos
)
3081 struct hstate
*h
= &default_hstate
;
3085 if (!hugepages_supported())
3088 tmp
= h
->nr_overcommit_huge_pages
;
3090 if (write
&& hstate_is_gigantic(h
))
3094 table
->maxlen
= sizeof(unsigned long);
3095 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3100 spin_lock(&hugetlb_lock
);
3101 h
->nr_overcommit_huge_pages
= tmp
;
3102 spin_unlock(&hugetlb_lock
);
3108 #endif /* CONFIG_SYSCTL */
3110 void hugetlb_report_meminfo(struct seq_file
*m
)
3113 unsigned long total
= 0;
3115 if (!hugepages_supported())
3118 for_each_hstate(h
) {
3119 unsigned long count
= h
->nr_huge_pages
;
3121 total
+= (PAGE_SIZE
<< huge_page_order(h
)) * count
;
3123 if (h
== &default_hstate
)
3125 "HugePages_Total: %5lu\n"
3126 "HugePages_Free: %5lu\n"
3127 "HugePages_Rsvd: %5lu\n"
3128 "HugePages_Surp: %5lu\n"
3129 "Hugepagesize: %8lu kB\n",
3133 h
->surplus_huge_pages
,
3134 (PAGE_SIZE
<< huge_page_order(h
)) / 1024);
3137 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ 1024);
3140 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3142 struct hstate
*h
= &default_hstate
;
3143 if (!hugepages_supported())
3146 "Node %d HugePages_Total: %5u\n"
3147 "Node %d HugePages_Free: %5u\n"
3148 "Node %d HugePages_Surp: %5u\n",
3149 nid
, h
->nr_huge_pages_node
[nid
],
3150 nid
, h
->free_huge_pages_node
[nid
],
3151 nid
, h
->surplus_huge_pages_node
[nid
]);
3154 void hugetlb_show_meminfo(void)
3159 if (!hugepages_supported())
3162 for_each_node_state(nid
, N_MEMORY
)
3164 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3166 h
->nr_huge_pages_node
[nid
],
3167 h
->free_huge_pages_node
[nid
],
3168 h
->surplus_huge_pages_node
[nid
],
3169 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3172 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3174 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3175 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3178 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3179 unsigned long hugetlb_total_pages(void)
3182 unsigned long nr_total_pages
= 0;
3185 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3186 return nr_total_pages
;
3189 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3193 spin_lock(&hugetlb_lock
);
3195 * When cpuset is configured, it breaks the strict hugetlb page
3196 * reservation as the accounting is done on a global variable. Such
3197 * reservation is completely rubbish in the presence of cpuset because
3198 * the reservation is not checked against page availability for the
3199 * current cpuset. Application can still potentially OOM'ed by kernel
3200 * with lack of free htlb page in cpuset that the task is in.
3201 * Attempt to enforce strict accounting with cpuset is almost
3202 * impossible (or too ugly) because cpuset is too fluid that
3203 * task or memory node can be dynamically moved between cpusets.
3205 * The change of semantics for shared hugetlb mapping with cpuset is
3206 * undesirable. However, in order to preserve some of the semantics,
3207 * we fall back to check against current free page availability as
3208 * a best attempt and hopefully to minimize the impact of changing
3209 * semantics that cpuset has.
3212 if (gather_surplus_pages(h
, delta
) < 0)
3215 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3216 return_unused_surplus_pages(h
, delta
);
3223 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3226 spin_unlock(&hugetlb_lock
);
3230 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3232 struct resv_map
*resv
= vma_resv_map(vma
);
3235 * This new VMA should share its siblings reservation map if present.
3236 * The VMA will only ever have a valid reservation map pointer where
3237 * it is being copied for another still existing VMA. As that VMA
3238 * has a reference to the reservation map it cannot disappear until
3239 * after this open call completes. It is therefore safe to take a
3240 * new reference here without additional locking.
3242 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3243 kref_get(&resv
->refs
);
3246 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3248 struct hstate
*h
= hstate_vma(vma
);
3249 struct resv_map
*resv
= vma_resv_map(vma
);
3250 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3251 unsigned long reserve
, start
, end
;
3254 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3257 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3258 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3260 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3262 kref_put(&resv
->refs
, resv_map_release
);
3266 * Decrement reserve counts. The global reserve count may be
3267 * adjusted if the subpool has a minimum size.
3269 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3270 hugetlb_acct_memory(h
, -gbl_reserve
);
3274 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3276 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3281 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3283 struct hstate
*hstate
= hstate_vma(vma
);
3285 return 1UL << huge_page_shift(hstate
);
3289 * We cannot handle pagefaults against hugetlb pages at all. They cause
3290 * handle_mm_fault() to try to instantiate regular-sized pages in the
3291 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3294 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3301 * When a new function is introduced to vm_operations_struct and added
3302 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3303 * This is because under System V memory model, mappings created via
3304 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3305 * their original vm_ops are overwritten with shm_vm_ops.
3307 const struct vm_operations_struct hugetlb_vm_ops
= {
3308 .fault
= hugetlb_vm_op_fault
,
3309 .open
= hugetlb_vm_op_open
,
3310 .close
= hugetlb_vm_op_close
,
3311 .split
= hugetlb_vm_op_split
,
3312 .pagesize
= hugetlb_vm_op_pagesize
,
3315 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3321 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3322 vma
->vm_page_prot
)));
3324 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3325 vma
->vm_page_prot
));
3327 entry
= pte_mkyoung(entry
);
3328 entry
= pte_mkhuge(entry
);
3329 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3334 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3335 unsigned long address
, pte_t
*ptep
)
3339 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3340 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3341 update_mmu_cache(vma
, address
, ptep
);
3344 bool is_hugetlb_entry_migration(pte_t pte
)
3348 if (huge_pte_none(pte
) || pte_present(pte
))
3350 swp
= pte_to_swp_entry(pte
);
3351 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3357 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3361 if (huge_pte_none(pte
) || pte_present(pte
))
3363 swp
= pte_to_swp_entry(pte
);
3364 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3370 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3371 struct vm_area_struct
*vma
)
3373 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3374 struct page
*ptepage
;
3377 struct hstate
*h
= hstate_vma(vma
);
3378 unsigned long sz
= huge_page_size(h
);
3379 struct mmu_notifier_range range
;
3382 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3385 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3388 mmu_notifier_invalidate_range_start(&range
);
3391 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3392 spinlock_t
*src_ptl
, *dst_ptl
;
3393 src_pte
= huge_pte_offset(src
, addr
, sz
);
3396 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3403 * If the pagetables are shared don't copy or take references.
3404 * dst_pte == src_pte is the common case of src/dest sharing.
3406 * However, src could have 'unshared' and dst shares with
3407 * another vma. If dst_pte !none, this implies sharing.
3408 * Check here before taking page table lock, and once again
3409 * after taking the lock below.
3411 dst_entry
= huge_ptep_get(dst_pte
);
3412 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3415 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3416 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3417 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3418 entry
= huge_ptep_get(src_pte
);
3419 dst_entry
= huge_ptep_get(dst_pte
);
3420 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3422 * Skip if src entry none. Also, skip in the
3423 * unlikely case dst entry !none as this implies
3424 * sharing with another vma.
3427 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3428 is_hugetlb_entry_hwpoisoned(entry
))) {
3429 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3431 if (is_write_migration_entry(swp_entry
) && cow
) {
3433 * COW mappings require pages in both
3434 * parent and child to be set to read.
3436 make_migration_entry_read(&swp_entry
);
3437 entry
= swp_entry_to_pte(swp_entry
);
3438 set_huge_swap_pte_at(src
, addr
, src_pte
,
3441 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3445 * No need to notify as we are downgrading page
3446 * table protection not changing it to point
3449 * See Documentation/vm/mmu_notifier.rst
3451 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3453 entry
= huge_ptep_get(src_pte
);
3454 ptepage
= pte_page(entry
);
3456 page_dup_rmap(ptepage
, true);
3457 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3458 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3460 spin_unlock(src_ptl
);
3461 spin_unlock(dst_ptl
);
3465 mmu_notifier_invalidate_range_end(&range
);
3470 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3471 unsigned long start
, unsigned long end
,
3472 struct page
*ref_page
)
3474 struct mm_struct
*mm
= vma
->vm_mm
;
3475 unsigned long address
;
3480 struct hstate
*h
= hstate_vma(vma
);
3481 unsigned long sz
= huge_page_size(h
);
3482 struct mmu_notifier_range range
;
3484 WARN_ON(!is_vm_hugetlb_page(vma
));
3485 BUG_ON(start
& ~huge_page_mask(h
));
3486 BUG_ON(end
& ~huge_page_mask(h
));
3489 * This is a hugetlb vma, all the pte entries should point
3492 tlb_change_page_size(tlb
, sz
);
3493 tlb_start_vma(tlb
, vma
);
3496 * If sharing possible, alert mmu notifiers of worst case.
3498 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3500 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3501 mmu_notifier_invalidate_range_start(&range
);
3503 for (; address
< end
; address
+= sz
) {
3504 ptep
= huge_pte_offset(mm
, address
, sz
);
3508 ptl
= huge_pte_lock(h
, mm
, ptep
);
3509 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3512 * We just unmapped a page of PMDs by clearing a PUD.
3513 * The caller's TLB flush range should cover this area.
3518 pte
= huge_ptep_get(ptep
);
3519 if (huge_pte_none(pte
)) {
3525 * Migrating hugepage or HWPoisoned hugepage is already
3526 * unmapped and its refcount is dropped, so just clear pte here.
3528 if (unlikely(!pte_present(pte
))) {
3529 huge_pte_clear(mm
, address
, ptep
, sz
);
3534 page
= pte_page(pte
);
3536 * If a reference page is supplied, it is because a specific
3537 * page is being unmapped, not a range. Ensure the page we
3538 * are about to unmap is the actual page of interest.
3541 if (page
!= ref_page
) {
3546 * Mark the VMA as having unmapped its page so that
3547 * future faults in this VMA will fail rather than
3548 * looking like data was lost
3550 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3553 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3554 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3555 if (huge_pte_dirty(pte
))
3556 set_page_dirty(page
);
3558 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3559 page_remove_rmap(page
, true);
3562 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3564 * Bail out after unmapping reference page if supplied
3569 mmu_notifier_invalidate_range_end(&range
);
3570 tlb_end_vma(tlb
, vma
);
3573 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3574 struct vm_area_struct
*vma
, unsigned long start
,
3575 unsigned long end
, struct page
*ref_page
)
3577 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3580 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3581 * test will fail on a vma being torn down, and not grab a page table
3582 * on its way out. We're lucky that the flag has such an appropriate
3583 * name, and can in fact be safely cleared here. We could clear it
3584 * before the __unmap_hugepage_range above, but all that's necessary
3585 * is to clear it before releasing the i_mmap_rwsem. This works
3586 * because in the context this is called, the VMA is about to be
3587 * destroyed and the i_mmap_rwsem is held.
3589 vma
->vm_flags
&= ~VM_MAYSHARE
;
3592 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3593 unsigned long end
, struct page
*ref_page
)
3595 struct mm_struct
*mm
;
3596 struct mmu_gather tlb
;
3597 unsigned long tlb_start
= start
;
3598 unsigned long tlb_end
= end
;
3601 * If shared PMDs were possibly used within this vma range, adjust
3602 * start/end for worst case tlb flushing.
3603 * Note that we can not be sure if PMDs are shared until we try to
3604 * unmap pages. However, we want to make sure TLB flushing covers
3605 * the largest possible range.
3607 adjust_range_if_pmd_sharing_possible(vma
, &tlb_start
, &tlb_end
);
3611 tlb_gather_mmu(&tlb
, mm
, tlb_start
, tlb_end
);
3612 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3613 tlb_finish_mmu(&tlb
, tlb_start
, tlb_end
);
3617 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3618 * mappping it owns the reserve page for. The intention is to unmap the page
3619 * from other VMAs and let the children be SIGKILLed if they are faulting the
3622 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3623 struct page
*page
, unsigned long address
)
3625 struct hstate
*h
= hstate_vma(vma
);
3626 struct vm_area_struct
*iter_vma
;
3627 struct address_space
*mapping
;
3631 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3632 * from page cache lookup which is in HPAGE_SIZE units.
3634 address
= address
& huge_page_mask(h
);
3635 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3637 mapping
= vma
->vm_file
->f_mapping
;
3640 * Take the mapping lock for the duration of the table walk. As
3641 * this mapping should be shared between all the VMAs,
3642 * __unmap_hugepage_range() is called as the lock is already held
3644 i_mmap_lock_write(mapping
);
3645 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3646 /* Do not unmap the current VMA */
3647 if (iter_vma
== vma
)
3651 * Shared VMAs have their own reserves and do not affect
3652 * MAP_PRIVATE accounting but it is possible that a shared
3653 * VMA is using the same page so check and skip such VMAs.
3655 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3659 * Unmap the page from other VMAs without their own reserves.
3660 * They get marked to be SIGKILLed if they fault in these
3661 * areas. This is because a future no-page fault on this VMA
3662 * could insert a zeroed page instead of the data existing
3663 * from the time of fork. This would look like data corruption
3665 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3666 unmap_hugepage_range(iter_vma
, address
,
3667 address
+ huge_page_size(h
), page
);
3669 i_mmap_unlock_write(mapping
);
3673 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3674 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3675 * cannot race with other handlers or page migration.
3676 * Keep the pte_same checks anyway to make transition from the mutex easier.
3678 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3679 unsigned long address
, pte_t
*ptep
,
3680 struct page
*pagecache_page
, spinlock_t
*ptl
)
3683 struct hstate
*h
= hstate_vma(vma
);
3684 struct page
*old_page
, *new_page
;
3685 int outside_reserve
= 0;
3687 unsigned long haddr
= address
& huge_page_mask(h
);
3688 struct mmu_notifier_range range
;
3690 pte
= huge_ptep_get(ptep
);
3691 old_page
= pte_page(pte
);
3694 /* If no-one else is actually using this page, avoid the copy
3695 * and just make the page writable */
3696 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3697 page_move_anon_rmap(old_page
, vma
);
3698 set_huge_ptep_writable(vma
, haddr
, ptep
);
3703 * If the process that created a MAP_PRIVATE mapping is about to
3704 * perform a COW due to a shared page count, attempt to satisfy
3705 * the allocation without using the existing reserves. The pagecache
3706 * page is used to determine if the reserve at this address was
3707 * consumed or not. If reserves were used, a partial faulted mapping
3708 * at the time of fork() could consume its reserves on COW instead
3709 * of the full address range.
3711 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3712 old_page
!= pagecache_page
)
3713 outside_reserve
= 1;
3718 * Drop page table lock as buddy allocator may be called. It will
3719 * be acquired again before returning to the caller, as expected.
3722 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
3724 if (IS_ERR(new_page
)) {
3726 * If a process owning a MAP_PRIVATE mapping fails to COW,
3727 * it is due to references held by a child and an insufficient
3728 * huge page pool. To guarantee the original mappers
3729 * reliability, unmap the page from child processes. The child
3730 * may get SIGKILLed if it later faults.
3732 if (outside_reserve
) {
3734 BUG_ON(huge_pte_none(pte
));
3735 unmap_ref_private(mm
, vma
, old_page
, haddr
);
3736 BUG_ON(huge_pte_none(pte
));
3738 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3740 pte_same(huge_ptep_get(ptep
), pte
)))
3741 goto retry_avoidcopy
;
3743 * race occurs while re-acquiring page table
3744 * lock, and our job is done.
3749 ret
= vmf_error(PTR_ERR(new_page
));
3750 goto out_release_old
;
3754 * When the original hugepage is shared one, it does not have
3755 * anon_vma prepared.
3757 if (unlikely(anon_vma_prepare(vma
))) {
3759 goto out_release_all
;
3762 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3763 pages_per_huge_page(h
));
3764 __SetPageUptodate(new_page
);
3766 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
3767 haddr
+ huge_page_size(h
));
3768 mmu_notifier_invalidate_range_start(&range
);
3771 * Retake the page table lock to check for racing updates
3772 * before the page tables are altered
3775 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3776 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3777 ClearPagePrivate(new_page
);
3780 huge_ptep_clear_flush(vma
, haddr
, ptep
);
3781 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
3782 set_huge_pte_at(mm
, haddr
, ptep
,
3783 make_huge_pte(vma
, new_page
, 1));
3784 page_remove_rmap(old_page
, true);
3785 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
3786 set_page_huge_active(new_page
);
3787 /* Make the old page be freed below */
3788 new_page
= old_page
;
3791 mmu_notifier_invalidate_range_end(&range
);
3793 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
3798 spin_lock(ptl
); /* Caller expects lock to be held */
3802 /* Return the pagecache page at a given address within a VMA */
3803 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3804 struct vm_area_struct
*vma
, unsigned long address
)
3806 struct address_space
*mapping
;
3809 mapping
= vma
->vm_file
->f_mapping
;
3810 idx
= vma_hugecache_offset(h
, vma
, address
);
3812 return find_lock_page(mapping
, idx
);
3816 * Return whether there is a pagecache page to back given address within VMA.
3817 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3819 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3820 struct vm_area_struct
*vma
, unsigned long address
)
3822 struct address_space
*mapping
;
3826 mapping
= vma
->vm_file
->f_mapping
;
3827 idx
= vma_hugecache_offset(h
, vma
, address
);
3829 page
= find_get_page(mapping
, idx
);
3832 return page
!= NULL
;
3835 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3838 struct inode
*inode
= mapping
->host
;
3839 struct hstate
*h
= hstate_inode(inode
);
3840 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3844 ClearPagePrivate(page
);
3847 * set page dirty so that it will not be removed from cache/file
3848 * by non-hugetlbfs specific code paths.
3850 set_page_dirty(page
);
3852 spin_lock(&inode
->i_lock
);
3853 inode
->i_blocks
+= blocks_per_huge_page(h
);
3854 spin_unlock(&inode
->i_lock
);
3858 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
3859 struct vm_area_struct
*vma
,
3860 struct address_space
*mapping
, pgoff_t idx
,
3861 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3863 struct hstate
*h
= hstate_vma(vma
);
3864 vm_fault_t ret
= VM_FAULT_SIGBUS
;
3870 unsigned long haddr
= address
& huge_page_mask(h
);
3871 bool new_page
= false;
3874 * Currently, we are forced to kill the process in the event the
3875 * original mapper has unmapped pages from the child due to a failed
3876 * COW. Warn that such a situation has occurred as it may not be obvious
3878 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3879 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3885 * Use page lock to guard against racing truncation
3886 * before we get page_table_lock.
3889 page
= find_lock_page(mapping
, idx
);
3891 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3896 * Check for page in userfault range
3898 if (userfaultfd_missing(vma
)) {
3900 struct vm_fault vmf
= {
3905 * Hard to debug if it ends up being
3906 * used by a callee that assumes
3907 * something about the other
3908 * uninitialized fields... same as in
3914 * hugetlb_fault_mutex must be dropped before
3915 * handling userfault. Reacquire after handling
3916 * fault to make calling code simpler.
3918 hash
= hugetlb_fault_mutex_hash(h
, mapping
, idx
, haddr
);
3919 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3920 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
3921 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3925 page
= alloc_huge_page(vma
, haddr
, 0);
3928 * Returning error will result in faulting task being
3929 * sent SIGBUS. The hugetlb fault mutex prevents two
3930 * tasks from racing to fault in the same page which
3931 * could result in false unable to allocate errors.
3932 * Page migration does not take the fault mutex, but
3933 * does a clear then write of pte's under page table
3934 * lock. Page fault code could race with migration,
3935 * notice the clear pte and try to allocate a page
3936 * here. Before returning error, get ptl and make
3937 * sure there really is no pte entry.
3939 ptl
= huge_pte_lock(h
, mm
, ptep
);
3940 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3946 ret
= vmf_error(PTR_ERR(page
));
3949 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3950 __SetPageUptodate(page
);
3953 if (vma
->vm_flags
& VM_MAYSHARE
) {
3954 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3963 if (unlikely(anon_vma_prepare(vma
))) {
3965 goto backout_unlocked
;
3971 * If memory error occurs between mmap() and fault, some process
3972 * don't have hwpoisoned swap entry for errored virtual address.
3973 * So we need to block hugepage fault by PG_hwpoison bit check.
3975 if (unlikely(PageHWPoison(page
))) {
3976 ret
= VM_FAULT_HWPOISON
|
3977 VM_FAULT_SET_HINDEX(hstate_index(h
));
3978 goto backout_unlocked
;
3983 * If we are going to COW a private mapping later, we examine the
3984 * pending reservations for this page now. This will ensure that
3985 * any allocations necessary to record that reservation occur outside
3988 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3989 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
3991 goto backout_unlocked
;
3993 /* Just decrements count, does not deallocate */
3994 vma_end_reservation(h
, vma
, haddr
);
3997 ptl
= huge_pte_lock(h
, mm
, ptep
);
3998 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4003 if (!huge_pte_none(huge_ptep_get(ptep
)))
4007 ClearPagePrivate(page
);
4008 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
4010 page_dup_rmap(page
, true);
4011 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
4012 && (vma
->vm_flags
& VM_SHARED
)));
4013 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
4015 hugetlb_count_add(pages_per_huge_page(h
), mm
);
4016 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
4017 /* Optimization, do the COW without a second fault */
4018 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
4024 * Only make newly allocated pages active. Existing pages found
4025 * in the pagecache could be !page_huge_active() if they have been
4026 * isolated for migration.
4029 set_page_huge_active(page
);
4039 restore_reserve_on_error(h
, vma
, haddr
, page
);
4045 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct address_space
*mapping
,
4046 pgoff_t idx
, unsigned long address
)
4048 unsigned long key
[2];
4051 key
[0] = (unsigned long) mapping
;
4054 hash
= jhash2((u32
*)&key
, sizeof(key
)/sizeof(u32
), 0);
4056 return hash
& (num_fault_mutexes
- 1);
4060 * For uniprocesor systems we always use a single mutex, so just
4061 * return 0 and avoid the hashing overhead.
4063 u32
hugetlb_fault_mutex_hash(struct hstate
*h
, struct address_space
*mapping
,
4064 pgoff_t idx
, unsigned long address
)
4070 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4071 unsigned long address
, unsigned int flags
)
4078 struct page
*page
= NULL
;
4079 struct page
*pagecache_page
= NULL
;
4080 struct hstate
*h
= hstate_vma(vma
);
4081 struct address_space
*mapping
;
4082 int need_wait_lock
= 0;
4083 unsigned long haddr
= address
& huge_page_mask(h
);
4085 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4087 entry
= huge_ptep_get(ptep
);
4088 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4089 migration_entry_wait_huge(vma
, mm
, ptep
);
4091 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4092 return VM_FAULT_HWPOISON_LARGE
|
4093 VM_FAULT_SET_HINDEX(hstate_index(h
));
4095 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4097 return VM_FAULT_OOM
;
4100 mapping
= vma
->vm_file
->f_mapping
;
4101 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4104 * Serialize hugepage allocation and instantiation, so that we don't
4105 * get spurious allocation failures if two CPUs race to instantiate
4106 * the same page in the page cache.
4108 hash
= hugetlb_fault_mutex_hash(h
, mapping
, idx
, haddr
);
4109 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4111 entry
= huge_ptep_get(ptep
);
4112 if (huge_pte_none(entry
)) {
4113 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4120 * entry could be a migration/hwpoison entry at this point, so this
4121 * check prevents the kernel from going below assuming that we have
4122 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4123 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4126 if (!pte_present(entry
))
4130 * If we are going to COW the mapping later, we examine the pending
4131 * reservations for this page now. This will ensure that any
4132 * allocations necessary to record that reservation occur outside the
4133 * spinlock. For private mappings, we also lookup the pagecache
4134 * page now as it is used to determine if a reservation has been
4137 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4138 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4142 /* Just decrements count, does not deallocate */
4143 vma_end_reservation(h
, vma
, haddr
);
4145 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4146 pagecache_page
= hugetlbfs_pagecache_page(h
,
4150 ptl
= huge_pte_lock(h
, mm
, ptep
);
4152 /* Check for a racing update before calling hugetlb_cow */
4153 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4157 * hugetlb_cow() requires page locks of pte_page(entry) and
4158 * pagecache_page, so here we need take the former one
4159 * when page != pagecache_page or !pagecache_page.
4161 page
= pte_page(entry
);
4162 if (page
!= pagecache_page
)
4163 if (!trylock_page(page
)) {
4170 if (flags
& FAULT_FLAG_WRITE
) {
4171 if (!huge_pte_write(entry
)) {
4172 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4173 pagecache_page
, ptl
);
4176 entry
= huge_pte_mkdirty(entry
);
4178 entry
= pte_mkyoung(entry
);
4179 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4180 flags
& FAULT_FLAG_WRITE
))
4181 update_mmu_cache(vma
, haddr
, ptep
);
4183 if (page
!= pagecache_page
)
4189 if (pagecache_page
) {
4190 unlock_page(pagecache_page
);
4191 put_page(pagecache_page
);
4194 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4196 * Generally it's safe to hold refcount during waiting page lock. But
4197 * here we just wait to defer the next page fault to avoid busy loop and
4198 * the page is not used after unlocked before returning from the current
4199 * page fault. So we are safe from accessing freed page, even if we wait
4200 * here without taking refcount.
4203 wait_on_page_locked(page
);
4208 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4209 * modifications for huge pages.
4211 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4213 struct vm_area_struct
*dst_vma
,
4214 unsigned long dst_addr
,
4215 unsigned long src_addr
,
4216 struct page
**pagep
)
4218 struct address_space
*mapping
;
4221 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4222 struct hstate
*h
= hstate_vma(dst_vma
);
4230 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4234 ret
= copy_huge_page_from_user(page
,
4235 (const void __user
*) src_addr
,
4236 pages_per_huge_page(h
), false);
4238 /* fallback to copy_from_user outside mmap_sem */
4239 if (unlikely(ret
)) {
4242 /* don't free the page */
4251 * The memory barrier inside __SetPageUptodate makes sure that
4252 * preceding stores to the page contents become visible before
4253 * the set_pte_at() write.
4255 __SetPageUptodate(page
);
4257 mapping
= dst_vma
->vm_file
->f_mapping
;
4258 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4261 * If shared, add to page cache
4264 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4267 goto out_release_nounlock
;
4270 * Serialization between remove_inode_hugepages() and
4271 * huge_add_to_page_cache() below happens through the
4272 * hugetlb_fault_mutex_table that here must be hold by
4275 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4277 goto out_release_nounlock
;
4280 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4284 * Recheck the i_size after holding PT lock to make sure not
4285 * to leave any page mapped (as page_mapped()) beyond the end
4286 * of the i_size (remove_inode_hugepages() is strict about
4287 * enforcing that). If we bail out here, we'll also leave a
4288 * page in the radix tree in the vm_shared case beyond the end
4289 * of the i_size, but remove_inode_hugepages() will take care
4290 * of it as soon as we drop the hugetlb_fault_mutex_table.
4292 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4295 goto out_release_unlock
;
4298 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4299 goto out_release_unlock
;
4302 page_dup_rmap(page
, true);
4304 ClearPagePrivate(page
);
4305 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4308 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4309 if (dst_vma
->vm_flags
& VM_WRITE
)
4310 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4311 _dst_pte
= pte_mkyoung(_dst_pte
);
4313 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4315 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4316 dst_vma
->vm_flags
& VM_WRITE
);
4317 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4319 /* No need to invalidate - it was non-present before */
4320 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4323 set_page_huge_active(page
);
4333 out_release_nounlock
:
4338 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4339 struct page
**pages
, struct vm_area_struct
**vmas
,
4340 unsigned long *position
, unsigned long *nr_pages
,
4341 long i
, unsigned int flags
, int *nonblocking
)
4343 unsigned long pfn_offset
;
4344 unsigned long vaddr
= *position
;
4345 unsigned long remainder
= *nr_pages
;
4346 struct hstate
*h
= hstate_vma(vma
);
4349 while (vaddr
< vma
->vm_end
&& remainder
) {
4351 spinlock_t
*ptl
= NULL
;
4356 * If we have a pending SIGKILL, don't keep faulting pages and
4357 * potentially allocating memory.
4359 if (fatal_signal_pending(current
)) {
4365 * Some archs (sparc64, sh*) have multiple pte_ts to
4366 * each hugepage. We have to make sure we get the
4367 * first, for the page indexing below to work.
4369 * Note that page table lock is not held when pte is null.
4371 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4374 ptl
= huge_pte_lock(h
, mm
, pte
);
4375 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4378 * When coredumping, it suits get_dump_page if we just return
4379 * an error where there's an empty slot with no huge pagecache
4380 * to back it. This way, we avoid allocating a hugepage, and
4381 * the sparse dumpfile avoids allocating disk blocks, but its
4382 * huge holes still show up with zeroes where they need to be.
4384 if (absent
&& (flags
& FOLL_DUMP
) &&
4385 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4393 * We need call hugetlb_fault for both hugepages under migration
4394 * (in which case hugetlb_fault waits for the migration,) and
4395 * hwpoisoned hugepages (in which case we need to prevent the
4396 * caller from accessing to them.) In order to do this, we use
4397 * here is_swap_pte instead of is_hugetlb_entry_migration and
4398 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4399 * both cases, and because we can't follow correct pages
4400 * directly from any kind of swap entries.
4402 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4403 ((flags
& FOLL_WRITE
) &&
4404 !huge_pte_write(huge_ptep_get(pte
)))) {
4406 unsigned int fault_flags
= 0;
4410 if (flags
& FOLL_WRITE
)
4411 fault_flags
|= FAULT_FLAG_WRITE
;
4413 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
4414 if (flags
& FOLL_NOWAIT
)
4415 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4416 FAULT_FLAG_RETRY_NOWAIT
;
4417 if (flags
& FOLL_TRIED
) {
4418 VM_WARN_ON_ONCE(fault_flags
&
4419 FAULT_FLAG_ALLOW_RETRY
);
4420 fault_flags
|= FAULT_FLAG_TRIED
;
4422 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4423 if (ret
& VM_FAULT_ERROR
) {
4424 err
= vm_fault_to_errno(ret
, flags
);
4428 if (ret
& VM_FAULT_RETRY
) {
4430 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4434 * VM_FAULT_RETRY must not return an
4435 * error, it will return zero
4438 * No need to update "position" as the
4439 * caller will not check it after
4440 * *nr_pages is set to 0.
4447 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4448 page
= pte_page(huge_ptep_get(pte
));
4451 * Instead of doing 'try_get_page()' below in the same_page
4452 * loop, just check the count once here.
4454 if (unlikely(page_count(page
) <= 0)) {
4464 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4475 if (vaddr
< vma
->vm_end
&& remainder
&&
4476 pfn_offset
< pages_per_huge_page(h
)) {
4478 * We use pfn_offset to avoid touching the pageframes
4479 * of this compound page.
4485 *nr_pages
= remainder
;
4487 * setting position is actually required only if remainder is
4488 * not zero but it's faster not to add a "if (remainder)"
4496 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4498 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4501 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4504 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4505 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4507 struct mm_struct
*mm
= vma
->vm_mm
;
4508 unsigned long start
= address
;
4511 struct hstate
*h
= hstate_vma(vma
);
4512 unsigned long pages
= 0;
4513 bool shared_pmd
= false;
4514 struct mmu_notifier_range range
;
4517 * In the case of shared PMDs, the area to flush could be beyond
4518 * start/end. Set range.start/range.end to cover the maximum possible
4519 * range if PMD sharing is possible.
4521 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
4522 0, vma
, mm
, start
, end
);
4523 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
4525 BUG_ON(address
>= end
);
4526 flush_cache_range(vma
, range
.start
, range
.end
);
4528 mmu_notifier_invalidate_range_start(&range
);
4529 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4530 for (; address
< end
; address
+= huge_page_size(h
)) {
4532 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4535 ptl
= huge_pte_lock(h
, mm
, ptep
);
4536 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4542 pte
= huge_ptep_get(ptep
);
4543 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4547 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4548 swp_entry_t entry
= pte_to_swp_entry(pte
);
4550 if (is_write_migration_entry(entry
)) {
4553 make_migration_entry_read(&entry
);
4554 newpte
= swp_entry_to_pte(entry
);
4555 set_huge_swap_pte_at(mm
, address
, ptep
,
4556 newpte
, huge_page_size(h
));
4562 if (!huge_pte_none(pte
)) {
4565 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
4566 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
4567 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4568 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
4574 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4575 * may have cleared our pud entry and done put_page on the page table:
4576 * once we release i_mmap_rwsem, another task can do the final put_page
4577 * and that page table be reused and filled with junk. If we actually
4578 * did unshare a page of pmds, flush the range corresponding to the pud.
4581 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
4583 flush_hugetlb_tlb_range(vma
, start
, end
);
4585 * No need to call mmu_notifier_invalidate_range() we are downgrading
4586 * page table protection not changing it to point to a new page.
4588 * See Documentation/vm/mmu_notifier.rst
4590 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4591 mmu_notifier_invalidate_range_end(&range
);
4593 return pages
<< h
->order
;
4596 int hugetlb_reserve_pages(struct inode
*inode
,
4598 struct vm_area_struct
*vma
,
4599 vm_flags_t vm_flags
)
4602 struct hstate
*h
= hstate_inode(inode
);
4603 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4604 struct resv_map
*resv_map
;
4607 /* This should never happen */
4609 VM_WARN(1, "%s called with a negative range\n", __func__
);
4614 * Only apply hugepage reservation if asked. At fault time, an
4615 * attempt will be made for VM_NORESERVE to allocate a page
4616 * without using reserves
4618 if (vm_flags
& VM_NORESERVE
)
4622 * Shared mappings base their reservation on the number of pages that
4623 * are already allocated on behalf of the file. Private mappings need
4624 * to reserve the full area even if read-only as mprotect() may be
4625 * called to make the mapping read-write. Assume !vma is a shm mapping
4627 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4629 * resv_map can not be NULL as hugetlb_reserve_pages is only
4630 * called for inodes for which resv_maps were created (see
4631 * hugetlbfs_get_inode).
4633 resv_map
= inode_resv_map(inode
);
4635 chg
= region_chg(resv_map
, from
, to
);
4638 resv_map
= resv_map_alloc();
4644 set_vma_resv_map(vma
, resv_map
);
4645 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4654 * There must be enough pages in the subpool for the mapping. If
4655 * the subpool has a minimum size, there may be some global
4656 * reservations already in place (gbl_reserve).
4658 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4659 if (gbl_reserve
< 0) {
4665 * Check enough hugepages are available for the reservation.
4666 * Hand the pages back to the subpool if there are not
4668 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4670 /* put back original number of pages, chg */
4671 (void)hugepage_subpool_put_pages(spool
, chg
);
4676 * Account for the reservations made. Shared mappings record regions
4677 * that have reservations as they are shared by multiple VMAs.
4678 * When the last VMA disappears, the region map says how much
4679 * the reservation was and the page cache tells how much of
4680 * the reservation was consumed. Private mappings are per-VMA and
4681 * only the consumed reservations are tracked. When the VMA
4682 * disappears, the original reservation is the VMA size and the
4683 * consumed reservations are stored in the map. Hence, nothing
4684 * else has to be done for private mappings here
4686 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4687 long add
= region_add(resv_map
, from
, to
);
4689 if (unlikely(chg
> add
)) {
4691 * pages in this range were added to the reserve
4692 * map between region_chg and region_add. This
4693 * indicates a race with alloc_huge_page. Adjust
4694 * the subpool and reserve counts modified above
4695 * based on the difference.
4699 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4701 hugetlb_acct_memory(h
, -rsv_adjust
);
4706 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4707 /* Don't call region_abort if region_chg failed */
4709 region_abort(resv_map
, from
, to
);
4710 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4711 kref_put(&resv_map
->refs
, resv_map_release
);
4715 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4718 struct hstate
*h
= hstate_inode(inode
);
4719 struct resv_map
*resv_map
= inode_resv_map(inode
);
4721 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4725 * Since this routine can be called in the evict inode path for all
4726 * hugetlbfs inodes, resv_map could be NULL.
4729 chg
= region_del(resv_map
, start
, end
);
4731 * region_del() can fail in the rare case where a region
4732 * must be split and another region descriptor can not be
4733 * allocated. If end == LONG_MAX, it will not fail.
4739 spin_lock(&inode
->i_lock
);
4740 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4741 spin_unlock(&inode
->i_lock
);
4744 * If the subpool has a minimum size, the number of global
4745 * reservations to be released may be adjusted.
4747 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4748 hugetlb_acct_memory(h
, -gbl_reserve
);
4753 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4754 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4755 struct vm_area_struct
*vma
,
4756 unsigned long addr
, pgoff_t idx
)
4758 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4760 unsigned long sbase
= saddr
& PUD_MASK
;
4761 unsigned long s_end
= sbase
+ PUD_SIZE
;
4763 /* Allow segments to share if only one is marked locked */
4764 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4765 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4768 * match the virtual addresses, permission and the alignment of the
4771 if (pmd_index(addr
) != pmd_index(saddr
) ||
4772 vm_flags
!= svm_flags
||
4773 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4779 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4781 unsigned long base
= addr
& PUD_MASK
;
4782 unsigned long end
= base
+ PUD_SIZE
;
4785 * check on proper vm_flags and page table alignment
4787 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
4793 * Determine if start,end range within vma could be mapped by shared pmd.
4794 * If yes, adjust start and end to cover range associated with possible
4795 * shared pmd mappings.
4797 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
4798 unsigned long *start
, unsigned long *end
)
4800 unsigned long check_addr
= *start
;
4802 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4805 for (check_addr
= *start
; check_addr
< *end
; check_addr
+= PUD_SIZE
) {
4806 unsigned long a_start
= check_addr
& PUD_MASK
;
4807 unsigned long a_end
= a_start
+ PUD_SIZE
;
4810 * If sharing is possible, adjust start/end if necessary.
4812 if (range_in_vma(vma
, a_start
, a_end
)) {
4813 if (a_start
< *start
)
4822 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4823 * and returns the corresponding pte. While this is not necessary for the
4824 * !shared pmd case because we can allocate the pmd later as well, it makes the
4825 * code much cleaner. pmd allocation is essential for the shared case because
4826 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4827 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4828 * bad pmd for sharing.
4830 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4832 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4833 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4834 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4836 struct vm_area_struct
*svma
;
4837 unsigned long saddr
;
4842 if (!vma_shareable(vma
, addr
))
4843 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4845 i_mmap_lock_write(mapping
);
4846 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4850 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4852 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
4853 vma_mmu_pagesize(svma
));
4855 get_page(virt_to_page(spte
));
4864 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
4865 if (pud_none(*pud
)) {
4866 pud_populate(mm
, pud
,
4867 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4870 put_page(virt_to_page(spte
));
4874 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4875 i_mmap_unlock_write(mapping
);
4880 * unmap huge page backed by shared pte.
4882 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4883 * indicated by page_count > 1, unmap is achieved by clearing pud and
4884 * decrementing the ref count. If count == 1, the pte page is not shared.
4886 * called with page table lock held.
4888 * returns: 1 successfully unmapped a shared pte page
4889 * 0 the underlying pte page is not shared, or it is the last user
4891 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4893 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4894 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
4895 pud_t
*pud
= pud_offset(p4d
, *addr
);
4897 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4898 if (page_count(virt_to_page(ptep
)) == 1)
4902 put_page(virt_to_page(ptep
));
4904 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4907 #define want_pmd_share() (1)
4908 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4909 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4914 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4919 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
4920 unsigned long *start
, unsigned long *end
)
4923 #define want_pmd_share() (0)
4924 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4926 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4927 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4928 unsigned long addr
, unsigned long sz
)
4935 pgd
= pgd_offset(mm
, addr
);
4936 p4d
= p4d_alloc(mm
, pgd
, addr
);
4939 pud
= pud_alloc(mm
, p4d
, addr
);
4941 if (sz
== PUD_SIZE
) {
4944 BUG_ON(sz
!= PMD_SIZE
);
4945 if (want_pmd_share() && pud_none(*pud
))
4946 pte
= huge_pmd_share(mm
, addr
, pud
);
4948 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4951 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
4957 * huge_pte_offset() - Walk the page table to resolve the hugepage
4958 * entry at address @addr
4960 * Return: Pointer to page table or swap entry (PUD or PMD) for
4961 * address @addr, or NULL if a p*d_none() entry is encountered and the
4962 * size @sz doesn't match the hugepage size at this level of the page
4965 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
4966 unsigned long addr
, unsigned long sz
)
4973 pgd
= pgd_offset(mm
, addr
);
4974 if (!pgd_present(*pgd
))
4976 p4d
= p4d_offset(pgd
, addr
);
4977 if (!p4d_present(*p4d
))
4980 pud
= pud_offset(p4d
, addr
);
4981 if (sz
!= PUD_SIZE
&& pud_none(*pud
))
4983 /* hugepage or swap? */
4984 if (pud_huge(*pud
) || !pud_present(*pud
))
4985 return (pte_t
*)pud
;
4987 pmd
= pmd_offset(pud
, addr
);
4988 if (sz
!= PMD_SIZE
&& pmd_none(*pmd
))
4990 /* hugepage or swap? */
4991 if (pmd_huge(*pmd
) || !pmd_present(*pmd
))
4992 return (pte_t
*)pmd
;
4997 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5000 * These functions are overwritable if your architecture needs its own
5003 struct page
* __weak
5004 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
5007 return ERR_PTR(-EINVAL
);
5010 struct page
* __weak
5011 follow_huge_pd(struct vm_area_struct
*vma
,
5012 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
5014 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5018 struct page
* __weak
5019 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
5020 pmd_t
*pmd
, int flags
)
5022 struct page
*page
= NULL
;
5026 ptl
= pmd_lockptr(mm
, pmd
);
5029 * make sure that the address range covered by this pmd is not
5030 * unmapped from other threads.
5032 if (!pmd_huge(*pmd
))
5034 pte
= huge_ptep_get((pte_t
*)pmd
);
5035 if (pte_present(pte
)) {
5036 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
5037 if (flags
& FOLL_GET
)
5040 if (is_hugetlb_entry_migration(pte
)) {
5042 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5046 * hwpoisoned entry is treated as no_page_table in
5047 * follow_page_mask().
5055 struct page
* __weak
5056 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5057 pud_t
*pud
, int flags
)
5059 if (flags
& FOLL_GET
)
5062 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5065 struct page
* __weak
5066 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5068 if (flags
& FOLL_GET
)
5071 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5074 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5078 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5079 spin_lock(&hugetlb_lock
);
5080 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
5084 clear_page_huge_active(page
);
5085 list_move_tail(&page
->lru
, list
);
5087 spin_unlock(&hugetlb_lock
);
5091 void putback_active_hugepage(struct page
*page
)
5093 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5094 spin_lock(&hugetlb_lock
);
5095 set_page_huge_active(page
);
5096 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5097 spin_unlock(&hugetlb_lock
);
5101 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5103 struct hstate
*h
= page_hstate(oldpage
);
5105 hugetlb_cgroup_migrate(oldpage
, newpage
);
5106 set_page_owner_migrate_reason(newpage
, reason
);
5109 * transfer temporary state of the new huge page. This is
5110 * reverse to other transitions because the newpage is going to
5111 * be final while the old one will be freed so it takes over
5112 * the temporary status.
5114 * Also note that we have to transfer the per-node surplus state
5115 * here as well otherwise the global surplus count will not match
5118 if (PageHugeTemporary(newpage
)) {
5119 int old_nid
= page_to_nid(oldpage
);
5120 int new_nid
= page_to_nid(newpage
);
5122 SetPageHugeTemporary(oldpage
);
5123 ClearPageHugeTemporary(newpage
);
5125 spin_lock(&hugetlb_lock
);
5126 if (h
->surplus_huge_pages_node
[old_nid
]) {
5127 h
->surplus_huge_pages_node
[old_nid
]--;
5128 h
->surplus_huge_pages_node
[new_nid
]++;
5130 spin_unlock(&hugetlb_lock
);