1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
9 #include <linux/seq_file.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/mmu_notifier.h>
13 #include <linux/nodemask.h>
14 #include <linux/pagemap.h>
15 #include <linux/mempolicy.h>
16 #include <linux/compiler.h>
17 #include <linux/cpuset.h>
18 #include <linux/mutex.h>
19 #include <linux/memblock.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/mmdebug.h>
23 #include <linux/sched/signal.h>
24 #include <linux/rmap.h>
25 #include <linux/string_helpers.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
28 #include <linux/jhash.h>
29 #include <linux/numa.h>
30 #include <linux/llist.h>
33 #include <asm/pgtable.h>
37 #include <linux/hugetlb.h>
38 #include <linux/hugetlb_cgroup.h>
39 #include <linux/node.h>
40 #include <linux/userfaultfd_k.h>
41 #include <linux/page_owner.h>
44 int hugetlb_max_hstate __read_mostly
;
45 unsigned int default_hstate_idx
;
46 struct hstate hstates
[HUGE_MAX_HSTATE
];
48 * Minimum page order among possible hugepage sizes, set to a proper value
51 static unsigned int minimum_order __read_mostly
= UINT_MAX
;
53 __initdata
LIST_HEAD(huge_boot_pages
);
55 /* for command line parsing */
56 static struct hstate
* __initdata parsed_hstate
;
57 static unsigned long __initdata default_hstate_max_huge_pages
;
58 static unsigned long __initdata default_hstate_size
;
59 static bool __initdata parsed_valid_hugepagesz
= true;
62 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
63 * free_huge_pages, and surplus_huge_pages.
65 DEFINE_SPINLOCK(hugetlb_lock
);
68 * Serializes faults on the same logical page. This is used to
69 * prevent spurious OOMs when the hugepage pool is fully utilized.
71 static int num_fault_mutexes
;
72 struct mutex
*hugetlb_fault_mutex_table ____cacheline_aligned_in_smp
;
74 /* Forward declaration */
75 static int hugetlb_acct_memory(struct hstate
*h
, long delta
);
77 static inline void unlock_or_release_subpool(struct hugepage_subpool
*spool
)
79 bool free
= (spool
->count
== 0) && (spool
->used_hpages
== 0);
81 spin_unlock(&spool
->lock
);
83 /* If no pages are used, and no other handles to the subpool
84 * remain, give up any reservations mased on minimum size and
87 if (spool
->min_hpages
!= -1)
88 hugetlb_acct_memory(spool
->hstate
,
94 struct hugepage_subpool
*hugepage_new_subpool(struct hstate
*h
, long max_hpages
,
97 struct hugepage_subpool
*spool
;
99 spool
= kzalloc(sizeof(*spool
), GFP_KERNEL
);
103 spin_lock_init(&spool
->lock
);
105 spool
->max_hpages
= max_hpages
;
107 spool
->min_hpages
= min_hpages
;
109 if (min_hpages
!= -1 && hugetlb_acct_memory(h
, min_hpages
)) {
113 spool
->rsv_hpages
= min_hpages
;
118 void hugepage_put_subpool(struct hugepage_subpool
*spool
)
120 spin_lock(&spool
->lock
);
121 BUG_ON(!spool
->count
);
123 unlock_or_release_subpool(spool
);
127 * Subpool accounting for allocating and reserving pages.
128 * Return -ENOMEM if there are not enough resources to satisfy the
129 * the request. Otherwise, return the number of pages by which the
130 * global pools must be adjusted (upward). The returned value may
131 * only be different than the passed value (delta) in the case where
132 * a subpool minimum size must be manitained.
134 static long hugepage_subpool_get_pages(struct hugepage_subpool
*spool
,
142 spin_lock(&spool
->lock
);
144 if (spool
->max_hpages
!= -1) { /* maximum size accounting */
145 if ((spool
->used_hpages
+ delta
) <= spool
->max_hpages
)
146 spool
->used_hpages
+= delta
;
153 /* minimum size accounting */
154 if (spool
->min_hpages
!= -1 && spool
->rsv_hpages
) {
155 if (delta
> spool
->rsv_hpages
) {
157 * Asking for more reserves than those already taken on
158 * behalf of subpool. Return difference.
160 ret
= delta
- spool
->rsv_hpages
;
161 spool
->rsv_hpages
= 0;
163 ret
= 0; /* reserves already accounted for */
164 spool
->rsv_hpages
-= delta
;
169 spin_unlock(&spool
->lock
);
174 * Subpool accounting for freeing and unreserving pages.
175 * Return the number of global page reservations that must be dropped.
176 * The return value may only be different than the passed value (delta)
177 * in the case where a subpool minimum size must be maintained.
179 static long hugepage_subpool_put_pages(struct hugepage_subpool
*spool
,
187 spin_lock(&spool
->lock
);
189 if (spool
->max_hpages
!= -1) /* maximum size accounting */
190 spool
->used_hpages
-= delta
;
192 /* minimum size accounting */
193 if (spool
->min_hpages
!= -1 && spool
->used_hpages
< spool
->min_hpages
) {
194 if (spool
->rsv_hpages
+ delta
<= spool
->min_hpages
)
197 ret
= spool
->rsv_hpages
+ delta
- spool
->min_hpages
;
199 spool
->rsv_hpages
+= delta
;
200 if (spool
->rsv_hpages
> spool
->min_hpages
)
201 spool
->rsv_hpages
= spool
->min_hpages
;
205 * If hugetlbfs_put_super couldn't free spool due to an outstanding
206 * quota reference, free it now.
208 unlock_or_release_subpool(spool
);
213 static inline struct hugepage_subpool
*subpool_inode(struct inode
*inode
)
215 return HUGETLBFS_SB(inode
->i_sb
)->spool
;
218 static inline struct hugepage_subpool
*subpool_vma(struct vm_area_struct
*vma
)
220 return subpool_inode(file_inode(vma
->vm_file
));
224 * Region tracking -- allows tracking of reservations and instantiated pages
225 * across the pages in a mapping.
227 * The region data structures are embedded into a resv_map and protected
228 * by a resv_map's lock. The set of regions within the resv_map represent
229 * reservations for huge pages, or huge pages that have already been
230 * instantiated within the map. The from and to elements are huge page
231 * indicies into the associated mapping. from indicates the starting index
232 * of the region. to represents the first index past the end of the region.
234 * For example, a file region structure with from == 0 and to == 4 represents
235 * four huge pages in a mapping. It is important to note that the to element
236 * represents the first element past the end of the region. This is used in
237 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
239 * Interval notation of the form [from, to) will be used to indicate that
240 * the endpoint from is inclusive and to is exclusive.
243 struct list_head link
;
248 /* Must be called with resv->lock held. Calling this with count_only == true
249 * will count the number of pages to be added but will not modify the linked
252 static long add_reservation_in_range(struct resv_map
*resv
, long f
, long t
,
256 struct list_head
*head
= &resv
->regions
;
257 struct file_region
*rg
= NULL
, *trg
= NULL
, *nrg
= NULL
;
259 /* Locate the region we are before or in. */
260 list_for_each_entry(rg
, head
, link
)
264 /* Round our left edge to the current segment if it encloses us. */
270 /* Check for and consume any regions we now overlap with. */
272 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
273 if (&rg
->link
== head
)
278 /* We overlap with this area, if it extends further than
279 * us then we must extend ourselves. Account for its
280 * existing reservation.
286 chg
-= rg
->to
- rg
->from
;
288 if (!count_only
&& rg
!= nrg
) {
303 * Add the huge page range represented by [f, t) to the reserve
304 * map. Existing regions will be expanded to accommodate the specified
305 * range, or a region will be taken from the cache. Sufficient regions
306 * must exist in the cache due to the previous call to region_chg with
309 * Return the number of new huge pages added to the map. This
310 * number is greater than or equal to zero.
312 static long region_add(struct resv_map
*resv
, long f
, long t
)
314 struct list_head
*head
= &resv
->regions
;
315 struct file_region
*rg
, *nrg
;
318 spin_lock(&resv
->lock
);
319 /* Locate the region we are either in or before. */
320 list_for_each_entry(rg
, head
, link
)
325 * If no region exists which can be expanded to include the
326 * specified range, pull a region descriptor from the cache
327 * and use it for this range.
329 if (&rg
->link
== head
|| t
< rg
->from
) {
330 VM_BUG_ON(resv
->region_cache_count
<= 0);
332 resv
->region_cache_count
--;
333 nrg
= list_first_entry(&resv
->region_cache
, struct file_region
,
335 list_del(&nrg
->link
);
339 list_add(&nrg
->link
, rg
->link
.prev
);
345 add
= add_reservation_in_range(resv
, f
, t
, false);
348 resv
->adds_in_progress
--;
349 spin_unlock(&resv
->lock
);
355 * Examine the existing reserve map and determine how many
356 * huge pages in the specified range [f, t) are NOT currently
357 * represented. This routine is called before a subsequent
358 * call to region_add that will actually modify the reserve
359 * map to add the specified range [f, t). region_chg does
360 * not change the number of huge pages represented by the
361 * map. A new file_region structure is added to the cache
362 * as a placeholder, so that the subsequent region_add
363 * call will have all the regions it needs and will not fail.
365 * Returns the number of huge pages that need to be added to the existing
366 * reservation map for the range [f, t). This number is greater or equal to
367 * zero. -ENOMEM is returned if a new file_region structure or cache entry
368 * is needed and can not be allocated.
370 static long region_chg(struct resv_map
*resv
, long f
, long t
)
374 spin_lock(&resv
->lock
);
376 resv
->adds_in_progress
++;
379 * Check for sufficient descriptors in the cache to accommodate
380 * the number of in progress add operations.
382 if (resv
->adds_in_progress
> resv
->region_cache_count
) {
383 struct file_region
*trg
;
385 VM_BUG_ON(resv
->adds_in_progress
- resv
->region_cache_count
> 1);
386 /* Must drop lock to allocate a new descriptor. */
387 resv
->adds_in_progress
--;
388 spin_unlock(&resv
->lock
);
390 trg
= kmalloc(sizeof(*trg
), GFP_KERNEL
);
394 spin_lock(&resv
->lock
);
395 list_add(&trg
->link
, &resv
->region_cache
);
396 resv
->region_cache_count
++;
400 chg
= add_reservation_in_range(resv
, f
, t
, true);
402 spin_unlock(&resv
->lock
);
407 * Abort the in progress add operation. The adds_in_progress field
408 * of the resv_map keeps track of the operations in progress between
409 * calls to region_chg and region_add. Operations are sometimes
410 * aborted after the call to region_chg. In such cases, region_abort
411 * is called to decrement the adds_in_progress counter.
413 * NOTE: The range arguments [f, t) are not needed or used in this
414 * routine. They are kept to make reading the calling code easier as
415 * arguments will match the associated region_chg call.
417 static void region_abort(struct resv_map
*resv
, long f
, long t
)
419 spin_lock(&resv
->lock
);
420 VM_BUG_ON(!resv
->region_cache_count
);
421 resv
->adds_in_progress
--;
422 spin_unlock(&resv
->lock
);
426 * Delete the specified range [f, t) from the reserve map. If the
427 * t parameter is LONG_MAX, this indicates that ALL regions after f
428 * should be deleted. Locate the regions which intersect [f, t)
429 * and either trim, delete or split the existing regions.
431 * Returns the number of huge pages deleted from the reserve map.
432 * In the normal case, the return value is zero or more. In the
433 * case where a region must be split, a new region descriptor must
434 * be allocated. If the allocation fails, -ENOMEM will be returned.
435 * NOTE: If the parameter t == LONG_MAX, then we will never split
436 * a region and possibly return -ENOMEM. Callers specifying
437 * t == LONG_MAX do not need to check for -ENOMEM error.
439 static long region_del(struct resv_map
*resv
, long f
, long t
)
441 struct list_head
*head
= &resv
->regions
;
442 struct file_region
*rg
, *trg
;
443 struct file_region
*nrg
= NULL
;
447 spin_lock(&resv
->lock
);
448 list_for_each_entry_safe(rg
, trg
, head
, link
) {
450 * Skip regions before the range to be deleted. file_region
451 * ranges are normally of the form [from, to). However, there
452 * may be a "placeholder" entry in the map which is of the form
453 * (from, to) with from == to. Check for placeholder entries
454 * at the beginning of the range to be deleted.
456 if (rg
->to
<= f
&& (rg
->to
!= rg
->from
|| rg
->to
!= f
))
462 if (f
> rg
->from
&& t
< rg
->to
) { /* Must split region */
464 * Check for an entry in the cache before dropping
465 * lock and attempting allocation.
468 resv
->region_cache_count
> resv
->adds_in_progress
) {
469 nrg
= list_first_entry(&resv
->region_cache
,
472 list_del(&nrg
->link
);
473 resv
->region_cache_count
--;
477 spin_unlock(&resv
->lock
);
478 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
486 /* New entry for end of split region */
489 INIT_LIST_HEAD(&nrg
->link
);
491 /* Original entry is trimmed */
494 list_add(&nrg
->link
, &rg
->link
);
499 if (f
<= rg
->from
&& t
>= rg
->to
) { /* Remove entire region */
500 del
+= rg
->to
- rg
->from
;
506 if (f
<= rg
->from
) { /* Trim beginning of region */
509 } else { /* Trim end of region */
515 spin_unlock(&resv
->lock
);
521 * A rare out of memory error was encountered which prevented removal of
522 * the reserve map region for a page. The huge page itself was free'ed
523 * and removed from the page cache. This routine will adjust the subpool
524 * usage count, and the global reserve count if needed. By incrementing
525 * these counts, the reserve map entry which could not be deleted will
526 * appear as a "reserved" entry instead of simply dangling with incorrect
529 void hugetlb_fix_reserve_counts(struct inode
*inode
)
531 struct hugepage_subpool
*spool
= subpool_inode(inode
);
534 rsv_adjust
= hugepage_subpool_get_pages(spool
, 1);
536 struct hstate
*h
= hstate_inode(inode
);
538 hugetlb_acct_memory(h
, 1);
543 * Count and return the number of huge pages in the reserve map
544 * that intersect with the range [f, t).
546 static long region_count(struct resv_map
*resv
, long f
, long t
)
548 struct list_head
*head
= &resv
->regions
;
549 struct file_region
*rg
;
552 spin_lock(&resv
->lock
);
553 /* Locate each segment we overlap with, and count that overlap. */
554 list_for_each_entry(rg
, head
, link
) {
563 seg_from
= max(rg
->from
, f
);
564 seg_to
= min(rg
->to
, t
);
566 chg
+= seg_to
- seg_from
;
568 spin_unlock(&resv
->lock
);
574 * Convert the address within this vma to the page offset within
575 * the mapping, in pagecache page units; huge pages here.
577 static pgoff_t
vma_hugecache_offset(struct hstate
*h
,
578 struct vm_area_struct
*vma
, unsigned long address
)
580 return ((address
- vma
->vm_start
) >> huge_page_shift(h
)) +
581 (vma
->vm_pgoff
>> huge_page_order(h
));
584 pgoff_t
linear_hugepage_index(struct vm_area_struct
*vma
,
585 unsigned long address
)
587 return vma_hugecache_offset(hstate_vma(vma
), vma
, address
);
589 EXPORT_SYMBOL_GPL(linear_hugepage_index
);
592 * Return the size of the pages allocated when backing a VMA. In the majority
593 * cases this will be same size as used by the page table entries.
595 unsigned long vma_kernel_pagesize(struct vm_area_struct
*vma
)
597 if (vma
->vm_ops
&& vma
->vm_ops
->pagesize
)
598 return vma
->vm_ops
->pagesize(vma
);
601 EXPORT_SYMBOL_GPL(vma_kernel_pagesize
);
604 * Return the page size being used by the MMU to back a VMA. In the majority
605 * of cases, the page size used by the kernel matches the MMU size. On
606 * architectures where it differs, an architecture-specific 'strong'
607 * version of this symbol is required.
609 __weak
unsigned long vma_mmu_pagesize(struct vm_area_struct
*vma
)
611 return vma_kernel_pagesize(vma
);
615 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
616 * bits of the reservation map pointer, which are always clear due to
619 #define HPAGE_RESV_OWNER (1UL << 0)
620 #define HPAGE_RESV_UNMAPPED (1UL << 1)
621 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
624 * These helpers are used to track how many pages are reserved for
625 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
626 * is guaranteed to have their future faults succeed.
628 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
629 * the reserve counters are updated with the hugetlb_lock held. It is safe
630 * to reset the VMA at fork() time as it is not in use yet and there is no
631 * chance of the global counters getting corrupted as a result of the values.
633 * The private mapping reservation is represented in a subtly different
634 * manner to a shared mapping. A shared mapping has a region map associated
635 * with the underlying file, this region map represents the backing file
636 * pages which have ever had a reservation assigned which this persists even
637 * after the page is instantiated. A private mapping has a region map
638 * associated with the original mmap which is attached to all VMAs which
639 * reference it, this region map represents those offsets which have consumed
640 * reservation ie. where pages have been instantiated.
642 static unsigned long get_vma_private_data(struct vm_area_struct
*vma
)
644 return (unsigned long)vma
->vm_private_data
;
647 static void set_vma_private_data(struct vm_area_struct
*vma
,
650 vma
->vm_private_data
= (void *)value
;
653 struct resv_map
*resv_map_alloc(void)
655 struct resv_map
*resv_map
= kmalloc(sizeof(*resv_map
), GFP_KERNEL
);
656 struct file_region
*rg
= kmalloc(sizeof(*rg
), GFP_KERNEL
);
658 if (!resv_map
|| !rg
) {
664 kref_init(&resv_map
->refs
);
665 spin_lock_init(&resv_map
->lock
);
666 INIT_LIST_HEAD(&resv_map
->regions
);
668 resv_map
->adds_in_progress
= 0;
670 INIT_LIST_HEAD(&resv_map
->region_cache
);
671 list_add(&rg
->link
, &resv_map
->region_cache
);
672 resv_map
->region_cache_count
= 1;
677 void resv_map_release(struct kref
*ref
)
679 struct resv_map
*resv_map
= container_of(ref
, struct resv_map
, refs
);
680 struct list_head
*head
= &resv_map
->region_cache
;
681 struct file_region
*rg
, *trg
;
683 /* Clear out any active regions before we release the map. */
684 region_del(resv_map
, 0, LONG_MAX
);
686 /* ... and any entries left in the cache */
687 list_for_each_entry_safe(rg
, trg
, head
, link
) {
692 VM_BUG_ON(resv_map
->adds_in_progress
);
697 static inline struct resv_map
*inode_resv_map(struct inode
*inode
)
700 * At inode evict time, i_mapping may not point to the original
701 * address space within the inode. This original address space
702 * contains the pointer to the resv_map. So, always use the
703 * address space embedded within the inode.
704 * The VERY common case is inode->mapping == &inode->i_data but,
705 * this may not be true for device special inodes.
707 return (struct resv_map
*)(&inode
->i_data
)->private_data
;
710 static struct resv_map
*vma_resv_map(struct vm_area_struct
*vma
)
712 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
713 if (vma
->vm_flags
& VM_MAYSHARE
) {
714 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
715 struct inode
*inode
= mapping
->host
;
717 return inode_resv_map(inode
);
720 return (struct resv_map
*)(get_vma_private_data(vma
) &
725 static void set_vma_resv_map(struct vm_area_struct
*vma
, struct resv_map
*map
)
727 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
728 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
730 set_vma_private_data(vma
, (get_vma_private_data(vma
) &
731 HPAGE_RESV_MASK
) | (unsigned long)map
);
734 static void set_vma_resv_flags(struct vm_area_struct
*vma
, unsigned long flags
)
736 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
737 VM_BUG_ON_VMA(vma
->vm_flags
& VM_MAYSHARE
, vma
);
739 set_vma_private_data(vma
, get_vma_private_data(vma
) | flags
);
742 static int is_vma_resv_set(struct vm_area_struct
*vma
, unsigned long flag
)
744 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
746 return (get_vma_private_data(vma
) & flag
) != 0;
749 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
750 void reset_vma_resv_huge_pages(struct vm_area_struct
*vma
)
752 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma
), vma
);
753 if (!(vma
->vm_flags
& VM_MAYSHARE
))
754 vma
->vm_private_data
= (void *)0;
757 /* Returns true if the VMA has associated reserve pages */
758 static bool vma_has_reserves(struct vm_area_struct
*vma
, long chg
)
760 if (vma
->vm_flags
& VM_NORESERVE
) {
762 * This address is already reserved by other process(chg == 0),
763 * so, we should decrement reserved count. Without decrementing,
764 * reserve count remains after releasing inode, because this
765 * allocated page will go into page cache and is regarded as
766 * coming from reserved pool in releasing step. Currently, we
767 * don't have any other solution to deal with this situation
768 * properly, so add work-around here.
770 if (vma
->vm_flags
& VM_MAYSHARE
&& chg
== 0)
776 /* Shared mappings always use reserves */
777 if (vma
->vm_flags
& VM_MAYSHARE
) {
779 * We know VM_NORESERVE is not set. Therefore, there SHOULD
780 * be a region map for all pages. The only situation where
781 * there is no region map is if a hole was punched via
782 * fallocate. In this case, there really are no reverves to
783 * use. This situation is indicated if chg != 0.
792 * Only the process that called mmap() has reserves for
795 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
)) {
797 * Like the shared case above, a hole punch or truncate
798 * could have been performed on the private mapping.
799 * Examine the value of chg to determine if reserves
800 * actually exist or were previously consumed.
801 * Very Subtle - The value of chg comes from a previous
802 * call to vma_needs_reserves(). The reserve map for
803 * private mappings has different (opposite) semantics
804 * than that of shared mappings. vma_needs_reserves()
805 * has already taken this difference in semantics into
806 * account. Therefore, the meaning of chg is the same
807 * as in the shared case above. Code could easily be
808 * combined, but keeping it separate draws attention to
809 * subtle differences.
820 static void enqueue_huge_page(struct hstate
*h
, struct page
*page
)
822 int nid
= page_to_nid(page
);
823 list_move(&page
->lru
, &h
->hugepage_freelists
[nid
]);
824 h
->free_huge_pages
++;
825 h
->free_huge_pages_node
[nid
]++;
828 static struct page
*dequeue_huge_page_node_exact(struct hstate
*h
, int nid
)
832 list_for_each_entry(page
, &h
->hugepage_freelists
[nid
], lru
)
833 if (!PageHWPoison(page
))
836 * if 'non-isolated free hugepage' not found on the list,
837 * the allocation fails.
839 if (&h
->hugepage_freelists
[nid
] == &page
->lru
)
841 list_move(&page
->lru
, &h
->hugepage_activelist
);
842 set_page_refcounted(page
);
843 h
->free_huge_pages
--;
844 h
->free_huge_pages_node
[nid
]--;
848 static struct page
*dequeue_huge_page_nodemask(struct hstate
*h
, gfp_t gfp_mask
, int nid
,
851 unsigned int cpuset_mems_cookie
;
852 struct zonelist
*zonelist
;
855 int node
= NUMA_NO_NODE
;
857 zonelist
= node_zonelist(nid
, gfp_mask
);
860 cpuset_mems_cookie
= read_mems_allowed_begin();
861 for_each_zone_zonelist_nodemask(zone
, z
, zonelist
, gfp_zone(gfp_mask
), nmask
) {
864 if (!cpuset_zone_allowed(zone
, gfp_mask
))
867 * no need to ask again on the same node. Pool is node rather than
870 if (zone_to_nid(zone
) == node
)
872 node
= zone_to_nid(zone
);
874 page
= dequeue_huge_page_node_exact(h
, node
);
878 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie
)))
884 /* Movability of hugepages depends on migration support. */
885 static inline gfp_t
htlb_alloc_mask(struct hstate
*h
)
887 if (hugepage_movable_supported(h
))
888 return GFP_HIGHUSER_MOVABLE
;
893 static struct page
*dequeue_huge_page_vma(struct hstate
*h
,
894 struct vm_area_struct
*vma
,
895 unsigned long address
, int avoid_reserve
,
899 struct mempolicy
*mpol
;
901 nodemask_t
*nodemask
;
905 * A child process with MAP_PRIVATE mappings created by their parent
906 * have no page reserves. This check ensures that reservations are
907 * not "stolen". The child may still get SIGKILLed
909 if (!vma_has_reserves(vma
, chg
) &&
910 h
->free_huge_pages
- h
->resv_huge_pages
== 0)
913 /* If reserves cannot be used, ensure enough pages are in the pool */
914 if (avoid_reserve
&& h
->free_huge_pages
- h
->resv_huge_pages
== 0)
917 gfp_mask
= htlb_alloc_mask(h
);
918 nid
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
919 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, nodemask
);
920 if (page
&& !avoid_reserve
&& vma_has_reserves(vma
, chg
)) {
921 SetPagePrivate(page
);
922 h
->resv_huge_pages
--;
933 * common helper functions for hstate_next_node_to_{alloc|free}.
934 * We may have allocated or freed a huge page based on a different
935 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
936 * be outside of *nodes_allowed. Ensure that we use an allowed
937 * node for alloc or free.
939 static int next_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
941 nid
= next_node_in(nid
, *nodes_allowed
);
942 VM_BUG_ON(nid
>= MAX_NUMNODES
);
947 static int get_valid_node_allowed(int nid
, nodemask_t
*nodes_allowed
)
949 if (!node_isset(nid
, *nodes_allowed
))
950 nid
= next_node_allowed(nid
, nodes_allowed
);
955 * returns the previously saved node ["this node"] from which to
956 * allocate a persistent huge page for the pool and advance the
957 * next node from which to allocate, handling wrap at end of node
960 static int hstate_next_node_to_alloc(struct hstate
*h
,
961 nodemask_t
*nodes_allowed
)
965 VM_BUG_ON(!nodes_allowed
);
967 nid
= get_valid_node_allowed(h
->next_nid_to_alloc
, nodes_allowed
);
968 h
->next_nid_to_alloc
= next_node_allowed(nid
, nodes_allowed
);
974 * helper for free_pool_huge_page() - return the previously saved
975 * node ["this node"] from which to free a huge page. Advance the
976 * next node id whether or not we find a free huge page to free so
977 * that the next attempt to free addresses the next node.
979 static int hstate_next_node_to_free(struct hstate
*h
, nodemask_t
*nodes_allowed
)
983 VM_BUG_ON(!nodes_allowed
);
985 nid
= get_valid_node_allowed(h
->next_nid_to_free
, nodes_allowed
);
986 h
->next_nid_to_free
= next_node_allowed(nid
, nodes_allowed
);
991 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
992 for (nr_nodes = nodes_weight(*mask); \
994 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
997 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
998 for (nr_nodes = nodes_weight(*mask); \
1000 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1003 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1004 static void destroy_compound_gigantic_page(struct page
*page
,
1008 int nr_pages
= 1 << order
;
1009 struct page
*p
= page
+ 1;
1011 atomic_set(compound_mapcount_ptr(page
), 0);
1012 if (hpage_pincount_available(page
))
1013 atomic_set(compound_pincount_ptr(page
), 0);
1015 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1016 clear_compound_head(p
);
1017 set_page_refcounted(p
);
1020 set_compound_order(page
, 0);
1021 __ClearPageHead(page
);
1024 static void free_gigantic_page(struct page
*page
, unsigned int order
)
1026 free_contig_range(page_to_pfn(page
), 1 << order
);
1029 #ifdef CONFIG_CONTIG_ALLOC
1030 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1031 int nid
, nodemask_t
*nodemask
)
1033 unsigned long nr_pages
= 1UL << huge_page_order(h
);
1035 return alloc_contig_pages(nr_pages
, gfp_mask
, nid
, nodemask
);
1038 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
);
1039 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
);
1040 #else /* !CONFIG_CONTIG_ALLOC */
1041 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1042 int nid
, nodemask_t
*nodemask
)
1046 #endif /* CONFIG_CONTIG_ALLOC */
1048 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1049 static struct page
*alloc_gigantic_page(struct hstate
*h
, gfp_t gfp_mask
,
1050 int nid
, nodemask_t
*nodemask
)
1054 static inline void free_gigantic_page(struct page
*page
, unsigned int order
) { }
1055 static inline void destroy_compound_gigantic_page(struct page
*page
,
1056 unsigned int order
) { }
1059 static void update_and_free_page(struct hstate
*h
, struct page
*page
)
1063 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
1067 h
->nr_huge_pages_node
[page_to_nid(page
)]--;
1068 for (i
= 0; i
< pages_per_huge_page(h
); i
++) {
1069 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
|
1070 1 << PG_referenced
| 1 << PG_dirty
|
1071 1 << PG_active
| 1 << PG_private
|
1074 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page
), page
);
1075 set_compound_page_dtor(page
, NULL_COMPOUND_DTOR
);
1076 set_page_refcounted(page
);
1077 if (hstate_is_gigantic(h
)) {
1078 destroy_compound_gigantic_page(page
, huge_page_order(h
));
1079 free_gigantic_page(page
, huge_page_order(h
));
1081 __free_pages(page
, huge_page_order(h
));
1085 struct hstate
*size_to_hstate(unsigned long size
)
1089 for_each_hstate(h
) {
1090 if (huge_page_size(h
) == size
)
1097 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1098 * to hstate->hugepage_activelist.)
1100 * This function can be called for tail pages, but never returns true for them.
1102 bool page_huge_active(struct page
*page
)
1104 VM_BUG_ON_PAGE(!PageHuge(page
), page
);
1105 return PageHead(page
) && PagePrivate(&page
[1]);
1108 /* never called for tail page */
1109 static void set_page_huge_active(struct page
*page
)
1111 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1112 SetPagePrivate(&page
[1]);
1115 static void clear_page_huge_active(struct page
*page
)
1117 VM_BUG_ON_PAGE(!PageHeadHuge(page
), page
);
1118 ClearPagePrivate(&page
[1]);
1122 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1125 static inline bool PageHugeTemporary(struct page
*page
)
1127 if (!PageHuge(page
))
1130 return (unsigned long)page
[2].mapping
== -1U;
1133 static inline void SetPageHugeTemporary(struct page
*page
)
1135 page
[2].mapping
= (void *)-1U;
1138 static inline void ClearPageHugeTemporary(struct page
*page
)
1140 page
[2].mapping
= NULL
;
1143 static void __free_huge_page(struct page
*page
)
1146 * Can't pass hstate in here because it is called from the
1147 * compound page destructor.
1149 struct hstate
*h
= page_hstate(page
);
1150 int nid
= page_to_nid(page
);
1151 struct hugepage_subpool
*spool
=
1152 (struct hugepage_subpool
*)page_private(page
);
1153 bool restore_reserve
;
1155 VM_BUG_ON_PAGE(page_count(page
), page
);
1156 VM_BUG_ON_PAGE(page_mapcount(page
), page
);
1158 set_page_private(page
, 0);
1159 page
->mapping
= NULL
;
1160 restore_reserve
= PagePrivate(page
);
1161 ClearPagePrivate(page
);
1164 * If PagePrivate() was set on page, page allocation consumed a
1165 * reservation. If the page was associated with a subpool, there
1166 * would have been a page reserved in the subpool before allocation
1167 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1168 * reservtion, do not call hugepage_subpool_put_pages() as this will
1169 * remove the reserved page from the subpool.
1171 if (!restore_reserve
) {
1173 * A return code of zero implies that the subpool will be
1174 * under its minimum size if the reservation is not restored
1175 * after page is free. Therefore, force restore_reserve
1178 if (hugepage_subpool_put_pages(spool
, 1) == 0)
1179 restore_reserve
= true;
1182 spin_lock(&hugetlb_lock
);
1183 clear_page_huge_active(page
);
1184 hugetlb_cgroup_uncharge_page(hstate_index(h
),
1185 pages_per_huge_page(h
), page
);
1186 if (restore_reserve
)
1187 h
->resv_huge_pages
++;
1189 if (PageHugeTemporary(page
)) {
1190 list_del(&page
->lru
);
1191 ClearPageHugeTemporary(page
);
1192 update_and_free_page(h
, page
);
1193 } else if (h
->surplus_huge_pages_node
[nid
]) {
1194 /* remove the page from active list */
1195 list_del(&page
->lru
);
1196 update_and_free_page(h
, page
);
1197 h
->surplus_huge_pages
--;
1198 h
->surplus_huge_pages_node
[nid
]--;
1200 arch_clear_hugepage_flags(page
);
1201 enqueue_huge_page(h
, page
);
1203 spin_unlock(&hugetlb_lock
);
1207 * As free_huge_page() can be called from a non-task context, we have
1208 * to defer the actual freeing in a workqueue to prevent potential
1209 * hugetlb_lock deadlock.
1211 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1212 * be freed and frees them one-by-one. As the page->mapping pointer is
1213 * going to be cleared in __free_huge_page() anyway, it is reused as the
1214 * llist_node structure of a lockless linked list of huge pages to be freed.
1216 static LLIST_HEAD(hpage_freelist
);
1218 static void free_hpage_workfn(struct work_struct
*work
)
1220 struct llist_node
*node
;
1223 node
= llist_del_all(&hpage_freelist
);
1226 page
= container_of((struct address_space
**)node
,
1227 struct page
, mapping
);
1229 __free_huge_page(page
);
1232 static DECLARE_WORK(free_hpage_work
, free_hpage_workfn
);
1234 void free_huge_page(struct page
*page
)
1237 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1241 * Only call schedule_work() if hpage_freelist is previously
1242 * empty. Otherwise, schedule_work() had been called but the
1243 * workfn hasn't retrieved the list yet.
1245 if (llist_add((struct llist_node
*)&page
->mapping
,
1247 schedule_work(&free_hpage_work
);
1251 __free_huge_page(page
);
1254 static void prep_new_huge_page(struct hstate
*h
, struct page
*page
, int nid
)
1256 INIT_LIST_HEAD(&page
->lru
);
1257 set_compound_page_dtor(page
, HUGETLB_PAGE_DTOR
);
1258 spin_lock(&hugetlb_lock
);
1259 set_hugetlb_cgroup(page
, NULL
);
1261 h
->nr_huge_pages_node
[nid
]++;
1262 spin_unlock(&hugetlb_lock
);
1265 static void prep_compound_gigantic_page(struct page
*page
, unsigned int order
)
1268 int nr_pages
= 1 << order
;
1269 struct page
*p
= page
+ 1;
1271 /* we rely on prep_new_huge_page to set the destructor */
1272 set_compound_order(page
, order
);
1273 __ClearPageReserved(page
);
1274 __SetPageHead(page
);
1275 for (i
= 1; i
< nr_pages
; i
++, p
= mem_map_next(p
, page
, i
)) {
1277 * For gigantic hugepages allocated through bootmem at
1278 * boot, it's safer to be consistent with the not-gigantic
1279 * hugepages and clear the PG_reserved bit from all tail pages
1280 * too. Otherwse drivers using get_user_pages() to access tail
1281 * pages may get the reference counting wrong if they see
1282 * PG_reserved set on a tail page (despite the head page not
1283 * having PG_reserved set). Enforcing this consistency between
1284 * head and tail pages allows drivers to optimize away a check
1285 * on the head page when they need know if put_page() is needed
1286 * after get_user_pages().
1288 __ClearPageReserved(p
);
1289 set_page_count(p
, 0);
1290 set_compound_head(p
, page
);
1292 atomic_set(compound_mapcount_ptr(page
), -1);
1294 if (hpage_pincount_available(page
))
1295 atomic_set(compound_pincount_ptr(page
), 0);
1299 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1300 * transparent huge pages. See the PageTransHuge() documentation for more
1303 int PageHuge(struct page
*page
)
1305 if (!PageCompound(page
))
1308 page
= compound_head(page
);
1309 return page
[1].compound_dtor
== HUGETLB_PAGE_DTOR
;
1311 EXPORT_SYMBOL_GPL(PageHuge
);
1314 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1315 * normal or transparent huge pages.
1317 int PageHeadHuge(struct page
*page_head
)
1319 if (!PageHead(page_head
))
1322 return get_compound_page_dtor(page_head
) == free_huge_page
;
1325 pgoff_t
__basepage_index(struct page
*page
)
1327 struct page
*page_head
= compound_head(page
);
1328 pgoff_t index
= page_index(page_head
);
1329 unsigned long compound_idx
;
1331 if (!PageHuge(page_head
))
1332 return page_index(page
);
1334 if (compound_order(page_head
) >= MAX_ORDER
)
1335 compound_idx
= page_to_pfn(page
) - page_to_pfn(page_head
);
1337 compound_idx
= page
- page_head
;
1339 return (index
<< compound_order(page_head
)) + compound_idx
;
1342 static struct page
*alloc_buddy_huge_page(struct hstate
*h
,
1343 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1344 nodemask_t
*node_alloc_noretry
)
1346 int order
= huge_page_order(h
);
1348 bool alloc_try_hard
= true;
1351 * By default we always try hard to allocate the page with
1352 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1353 * a loop (to adjust global huge page counts) and previous allocation
1354 * failed, do not continue to try hard on the same node. Use the
1355 * node_alloc_noretry bitmap to manage this state information.
1357 if (node_alloc_noretry
&& node_isset(nid
, *node_alloc_noretry
))
1358 alloc_try_hard
= false;
1359 gfp_mask
|= __GFP_COMP
|__GFP_NOWARN
;
1361 gfp_mask
|= __GFP_RETRY_MAYFAIL
;
1362 if (nid
== NUMA_NO_NODE
)
1363 nid
= numa_mem_id();
1364 page
= __alloc_pages_nodemask(gfp_mask
, order
, nid
, nmask
);
1366 __count_vm_event(HTLB_BUDDY_PGALLOC
);
1368 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL
);
1371 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1372 * indicates an overall state change. Clear bit so that we resume
1373 * normal 'try hard' allocations.
1375 if (node_alloc_noretry
&& page
&& !alloc_try_hard
)
1376 node_clear(nid
, *node_alloc_noretry
);
1379 * If we tried hard to get a page but failed, set bit so that
1380 * subsequent attempts will not try as hard until there is an
1381 * overall state change.
1383 if (node_alloc_noretry
&& !page
&& alloc_try_hard
)
1384 node_set(nid
, *node_alloc_noretry
);
1390 * Common helper to allocate a fresh hugetlb page. All specific allocators
1391 * should use this function to get new hugetlb pages
1393 static struct page
*alloc_fresh_huge_page(struct hstate
*h
,
1394 gfp_t gfp_mask
, int nid
, nodemask_t
*nmask
,
1395 nodemask_t
*node_alloc_noretry
)
1399 if (hstate_is_gigantic(h
))
1400 page
= alloc_gigantic_page(h
, gfp_mask
, nid
, nmask
);
1402 page
= alloc_buddy_huge_page(h
, gfp_mask
,
1403 nid
, nmask
, node_alloc_noretry
);
1407 if (hstate_is_gigantic(h
))
1408 prep_compound_gigantic_page(page
, huge_page_order(h
));
1409 prep_new_huge_page(h
, page
, page_to_nid(page
));
1415 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1418 static int alloc_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1419 nodemask_t
*node_alloc_noretry
)
1423 gfp_t gfp_mask
= htlb_alloc_mask(h
) | __GFP_THISNODE
;
1425 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
1426 page
= alloc_fresh_huge_page(h
, gfp_mask
, node
, nodes_allowed
,
1427 node_alloc_noretry
);
1435 put_page(page
); /* free it into the hugepage allocator */
1441 * Free huge page from pool from next node to free.
1442 * Attempt to keep persistent huge pages more or less
1443 * balanced over allowed nodes.
1444 * Called with hugetlb_lock locked.
1446 static int free_pool_huge_page(struct hstate
*h
, nodemask_t
*nodes_allowed
,
1452 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
1454 * If we're returning unused surplus pages, only examine
1455 * nodes with surplus pages.
1457 if ((!acct_surplus
|| h
->surplus_huge_pages_node
[node
]) &&
1458 !list_empty(&h
->hugepage_freelists
[node
])) {
1460 list_entry(h
->hugepage_freelists
[node
].next
,
1462 list_del(&page
->lru
);
1463 h
->free_huge_pages
--;
1464 h
->free_huge_pages_node
[node
]--;
1466 h
->surplus_huge_pages
--;
1467 h
->surplus_huge_pages_node
[node
]--;
1469 update_and_free_page(h
, page
);
1479 * Dissolve a given free hugepage into free buddy pages. This function does
1480 * nothing for in-use hugepages and non-hugepages.
1481 * This function returns values like below:
1483 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1484 * (allocated or reserved.)
1485 * 0: successfully dissolved free hugepages or the page is not a
1486 * hugepage (considered as already dissolved)
1488 int dissolve_free_huge_page(struct page
*page
)
1492 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1493 if (!PageHuge(page
))
1496 spin_lock(&hugetlb_lock
);
1497 if (!PageHuge(page
)) {
1502 if (!page_count(page
)) {
1503 struct page
*head
= compound_head(page
);
1504 struct hstate
*h
= page_hstate(head
);
1505 int nid
= page_to_nid(head
);
1506 if (h
->free_huge_pages
- h
->resv_huge_pages
== 0)
1509 * Move PageHWPoison flag from head page to the raw error page,
1510 * which makes any subpages rather than the error page reusable.
1512 if (PageHWPoison(head
) && page
!= head
) {
1513 SetPageHWPoison(page
);
1514 ClearPageHWPoison(head
);
1516 list_del(&head
->lru
);
1517 h
->free_huge_pages
--;
1518 h
->free_huge_pages_node
[nid
]--;
1519 h
->max_huge_pages
--;
1520 update_and_free_page(h
, head
);
1524 spin_unlock(&hugetlb_lock
);
1529 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1530 * make specified memory blocks removable from the system.
1531 * Note that this will dissolve a free gigantic hugepage completely, if any
1532 * part of it lies within the given range.
1533 * Also note that if dissolve_free_huge_page() returns with an error, all
1534 * free hugepages that were dissolved before that error are lost.
1536 int dissolve_free_huge_pages(unsigned long start_pfn
, unsigned long end_pfn
)
1542 if (!hugepages_supported())
1545 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= 1 << minimum_order
) {
1546 page
= pfn_to_page(pfn
);
1547 rc
= dissolve_free_huge_page(page
);
1556 * Allocates a fresh surplus page from the page allocator.
1558 static struct page
*alloc_surplus_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1559 int nid
, nodemask_t
*nmask
)
1561 struct page
*page
= NULL
;
1563 if (hstate_is_gigantic(h
))
1566 spin_lock(&hugetlb_lock
);
1567 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
)
1569 spin_unlock(&hugetlb_lock
);
1571 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1575 spin_lock(&hugetlb_lock
);
1577 * We could have raced with the pool size change.
1578 * Double check that and simply deallocate the new page
1579 * if we would end up overcommiting the surpluses. Abuse
1580 * temporary page to workaround the nasty free_huge_page
1583 if (h
->surplus_huge_pages
>= h
->nr_overcommit_huge_pages
) {
1584 SetPageHugeTemporary(page
);
1585 spin_unlock(&hugetlb_lock
);
1589 h
->surplus_huge_pages
++;
1590 h
->surplus_huge_pages_node
[page_to_nid(page
)]++;
1594 spin_unlock(&hugetlb_lock
);
1599 struct page
*alloc_migrate_huge_page(struct hstate
*h
, gfp_t gfp_mask
,
1600 int nid
, nodemask_t
*nmask
)
1604 if (hstate_is_gigantic(h
))
1607 page
= alloc_fresh_huge_page(h
, gfp_mask
, nid
, nmask
, NULL
);
1612 * We do not account these pages as surplus because they are only
1613 * temporary and will be released properly on the last reference
1615 SetPageHugeTemporary(page
);
1621 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1624 struct page
*alloc_buddy_huge_page_with_mpol(struct hstate
*h
,
1625 struct vm_area_struct
*vma
, unsigned long addr
)
1628 struct mempolicy
*mpol
;
1629 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1631 nodemask_t
*nodemask
;
1633 nid
= huge_node(vma
, addr
, gfp_mask
, &mpol
, &nodemask
);
1634 page
= alloc_surplus_huge_page(h
, gfp_mask
, nid
, nodemask
);
1635 mpol_cond_put(mpol
);
1640 /* page migration callback function */
1641 struct page
*alloc_huge_page_node(struct hstate
*h
, int nid
)
1643 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1644 struct page
*page
= NULL
;
1646 if (nid
!= NUMA_NO_NODE
)
1647 gfp_mask
|= __GFP_THISNODE
;
1649 spin_lock(&hugetlb_lock
);
1650 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0)
1651 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, nid
, NULL
);
1652 spin_unlock(&hugetlb_lock
);
1655 page
= alloc_migrate_huge_page(h
, gfp_mask
, nid
, NULL
);
1660 /* page migration callback function */
1661 struct page
*alloc_huge_page_nodemask(struct hstate
*h
, int preferred_nid
,
1664 gfp_t gfp_mask
= htlb_alloc_mask(h
);
1666 spin_lock(&hugetlb_lock
);
1667 if (h
->free_huge_pages
- h
->resv_huge_pages
> 0) {
1670 page
= dequeue_huge_page_nodemask(h
, gfp_mask
, preferred_nid
, nmask
);
1672 spin_unlock(&hugetlb_lock
);
1676 spin_unlock(&hugetlb_lock
);
1678 return alloc_migrate_huge_page(h
, gfp_mask
, preferred_nid
, nmask
);
1681 /* mempolicy aware migration callback */
1682 struct page
*alloc_huge_page_vma(struct hstate
*h
, struct vm_area_struct
*vma
,
1683 unsigned long address
)
1685 struct mempolicy
*mpol
;
1686 nodemask_t
*nodemask
;
1691 gfp_mask
= htlb_alloc_mask(h
);
1692 node
= huge_node(vma
, address
, gfp_mask
, &mpol
, &nodemask
);
1693 page
= alloc_huge_page_nodemask(h
, node
, nodemask
);
1694 mpol_cond_put(mpol
);
1700 * Increase the hugetlb pool such that it can accommodate a reservation
1703 static int gather_surplus_pages(struct hstate
*h
, int delta
)
1705 struct list_head surplus_list
;
1706 struct page
*page
, *tmp
;
1708 int needed
, allocated
;
1709 bool alloc_ok
= true;
1711 needed
= (h
->resv_huge_pages
+ delta
) - h
->free_huge_pages
;
1713 h
->resv_huge_pages
+= delta
;
1718 INIT_LIST_HEAD(&surplus_list
);
1722 spin_unlock(&hugetlb_lock
);
1723 for (i
= 0; i
< needed
; i
++) {
1724 page
= alloc_surplus_huge_page(h
, htlb_alloc_mask(h
),
1725 NUMA_NO_NODE
, NULL
);
1730 list_add(&page
->lru
, &surplus_list
);
1736 * After retaking hugetlb_lock, we need to recalculate 'needed'
1737 * because either resv_huge_pages or free_huge_pages may have changed.
1739 spin_lock(&hugetlb_lock
);
1740 needed
= (h
->resv_huge_pages
+ delta
) -
1741 (h
->free_huge_pages
+ allocated
);
1746 * We were not able to allocate enough pages to
1747 * satisfy the entire reservation so we free what
1748 * we've allocated so far.
1753 * The surplus_list now contains _at_least_ the number of extra pages
1754 * needed to accommodate the reservation. Add the appropriate number
1755 * of pages to the hugetlb pool and free the extras back to the buddy
1756 * allocator. Commit the entire reservation here to prevent another
1757 * process from stealing the pages as they are added to the pool but
1758 * before they are reserved.
1760 needed
+= allocated
;
1761 h
->resv_huge_pages
+= delta
;
1764 /* Free the needed pages to the hugetlb pool */
1765 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
1769 * This page is now managed by the hugetlb allocator and has
1770 * no users -- drop the buddy allocator's reference.
1772 put_page_testzero(page
);
1773 VM_BUG_ON_PAGE(page_count(page
), page
);
1774 enqueue_huge_page(h
, page
);
1777 spin_unlock(&hugetlb_lock
);
1779 /* Free unnecessary surplus pages to the buddy allocator */
1780 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
)
1782 spin_lock(&hugetlb_lock
);
1788 * This routine has two main purposes:
1789 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1790 * in unused_resv_pages. This corresponds to the prior adjustments made
1791 * to the associated reservation map.
1792 * 2) Free any unused surplus pages that may have been allocated to satisfy
1793 * the reservation. As many as unused_resv_pages may be freed.
1795 * Called with hugetlb_lock held. However, the lock could be dropped (and
1796 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1797 * we must make sure nobody else can claim pages we are in the process of
1798 * freeing. Do this by ensuring resv_huge_page always is greater than the
1799 * number of huge pages we plan to free when dropping the lock.
1801 static void return_unused_surplus_pages(struct hstate
*h
,
1802 unsigned long unused_resv_pages
)
1804 unsigned long nr_pages
;
1806 /* Cannot return gigantic pages currently */
1807 if (hstate_is_gigantic(h
))
1811 * Part (or even all) of the reservation could have been backed
1812 * by pre-allocated pages. Only free surplus pages.
1814 nr_pages
= min(unused_resv_pages
, h
->surplus_huge_pages
);
1817 * We want to release as many surplus pages as possible, spread
1818 * evenly across all nodes with memory. Iterate across these nodes
1819 * until we can no longer free unreserved surplus pages. This occurs
1820 * when the nodes with surplus pages have no free pages.
1821 * free_pool_huge_page() will balance the the freed pages across the
1822 * on-line nodes with memory and will handle the hstate accounting.
1824 * Note that we decrement resv_huge_pages as we free the pages. If
1825 * we drop the lock, resv_huge_pages will still be sufficiently large
1826 * to cover subsequent pages we may free.
1828 while (nr_pages
--) {
1829 h
->resv_huge_pages
--;
1830 unused_resv_pages
--;
1831 if (!free_pool_huge_page(h
, &node_states
[N_MEMORY
], 1))
1833 cond_resched_lock(&hugetlb_lock
);
1837 /* Fully uncommit the reservation */
1838 h
->resv_huge_pages
-= unused_resv_pages
;
1843 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1844 * are used by the huge page allocation routines to manage reservations.
1846 * vma_needs_reservation is called to determine if the huge page at addr
1847 * within the vma has an associated reservation. If a reservation is
1848 * needed, the value 1 is returned. The caller is then responsible for
1849 * managing the global reservation and subpool usage counts. After
1850 * the huge page has been allocated, vma_commit_reservation is called
1851 * to add the page to the reservation map. If the page allocation fails,
1852 * the reservation must be ended instead of committed. vma_end_reservation
1853 * is called in such cases.
1855 * In the normal case, vma_commit_reservation returns the same value
1856 * as the preceding vma_needs_reservation call. The only time this
1857 * is not the case is if a reserve map was changed between calls. It
1858 * is the responsibility of the caller to notice the difference and
1859 * take appropriate action.
1861 * vma_add_reservation is used in error paths where a reservation must
1862 * be restored when a newly allocated huge page must be freed. It is
1863 * to be called after calling vma_needs_reservation to determine if a
1864 * reservation exists.
1866 enum vma_resv_mode
{
1872 static long __vma_reservation_common(struct hstate
*h
,
1873 struct vm_area_struct
*vma
, unsigned long addr
,
1874 enum vma_resv_mode mode
)
1876 struct resv_map
*resv
;
1880 resv
= vma_resv_map(vma
);
1884 idx
= vma_hugecache_offset(h
, vma
, addr
);
1886 case VMA_NEEDS_RESV
:
1887 ret
= region_chg(resv
, idx
, idx
+ 1);
1889 case VMA_COMMIT_RESV
:
1890 ret
= region_add(resv
, idx
, idx
+ 1);
1893 region_abort(resv
, idx
, idx
+ 1);
1897 if (vma
->vm_flags
& VM_MAYSHARE
)
1898 ret
= region_add(resv
, idx
, idx
+ 1);
1900 region_abort(resv
, idx
, idx
+ 1);
1901 ret
= region_del(resv
, idx
, idx
+ 1);
1908 if (vma
->vm_flags
& VM_MAYSHARE
)
1910 else if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) && ret
>= 0) {
1912 * In most cases, reserves always exist for private mappings.
1913 * However, a file associated with mapping could have been
1914 * hole punched or truncated after reserves were consumed.
1915 * As subsequent fault on such a range will not use reserves.
1916 * Subtle - The reserve map for private mappings has the
1917 * opposite meaning than that of shared mappings. If NO
1918 * entry is in the reserve map, it means a reservation exists.
1919 * If an entry exists in the reserve map, it means the
1920 * reservation has already been consumed. As a result, the
1921 * return value of this routine is the opposite of the
1922 * value returned from reserve map manipulation routines above.
1930 return ret
< 0 ? ret
: 0;
1933 static long vma_needs_reservation(struct hstate
*h
,
1934 struct vm_area_struct
*vma
, unsigned long addr
)
1936 return __vma_reservation_common(h
, vma
, addr
, VMA_NEEDS_RESV
);
1939 static long vma_commit_reservation(struct hstate
*h
,
1940 struct vm_area_struct
*vma
, unsigned long addr
)
1942 return __vma_reservation_common(h
, vma
, addr
, VMA_COMMIT_RESV
);
1945 static void vma_end_reservation(struct hstate
*h
,
1946 struct vm_area_struct
*vma
, unsigned long addr
)
1948 (void)__vma_reservation_common(h
, vma
, addr
, VMA_END_RESV
);
1951 static long vma_add_reservation(struct hstate
*h
,
1952 struct vm_area_struct
*vma
, unsigned long addr
)
1954 return __vma_reservation_common(h
, vma
, addr
, VMA_ADD_RESV
);
1958 * This routine is called to restore a reservation on error paths. In the
1959 * specific error paths, a huge page was allocated (via alloc_huge_page)
1960 * and is about to be freed. If a reservation for the page existed,
1961 * alloc_huge_page would have consumed the reservation and set PagePrivate
1962 * in the newly allocated page. When the page is freed via free_huge_page,
1963 * the global reservation count will be incremented if PagePrivate is set.
1964 * However, free_huge_page can not adjust the reserve map. Adjust the
1965 * reserve map here to be consistent with global reserve count adjustments
1966 * to be made by free_huge_page.
1968 static void restore_reserve_on_error(struct hstate
*h
,
1969 struct vm_area_struct
*vma
, unsigned long address
,
1972 if (unlikely(PagePrivate(page
))) {
1973 long rc
= vma_needs_reservation(h
, vma
, address
);
1975 if (unlikely(rc
< 0)) {
1977 * Rare out of memory condition in reserve map
1978 * manipulation. Clear PagePrivate so that
1979 * global reserve count will not be incremented
1980 * by free_huge_page. This will make it appear
1981 * as though the reservation for this page was
1982 * consumed. This may prevent the task from
1983 * faulting in the page at a later time. This
1984 * is better than inconsistent global huge page
1985 * accounting of reserve counts.
1987 ClearPagePrivate(page
);
1989 rc
= vma_add_reservation(h
, vma
, address
);
1990 if (unlikely(rc
< 0))
1992 * See above comment about rare out of
1995 ClearPagePrivate(page
);
1997 vma_end_reservation(h
, vma
, address
);
2001 struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
2002 unsigned long addr
, int avoid_reserve
)
2004 struct hugepage_subpool
*spool
= subpool_vma(vma
);
2005 struct hstate
*h
= hstate_vma(vma
);
2007 long map_chg
, map_commit
;
2010 struct hugetlb_cgroup
*h_cg
;
2012 idx
= hstate_index(h
);
2014 * Examine the region/reserve map to determine if the process
2015 * has a reservation for the page to be allocated. A return
2016 * code of zero indicates a reservation exists (no change).
2018 map_chg
= gbl_chg
= vma_needs_reservation(h
, vma
, addr
);
2020 return ERR_PTR(-ENOMEM
);
2023 * Processes that did not create the mapping will have no
2024 * reserves as indicated by the region/reserve map. Check
2025 * that the allocation will not exceed the subpool limit.
2026 * Allocations for MAP_NORESERVE mappings also need to be
2027 * checked against any subpool limit.
2029 if (map_chg
|| avoid_reserve
) {
2030 gbl_chg
= hugepage_subpool_get_pages(spool
, 1);
2032 vma_end_reservation(h
, vma
, addr
);
2033 return ERR_PTR(-ENOSPC
);
2037 * Even though there was no reservation in the region/reserve
2038 * map, there could be reservations associated with the
2039 * subpool that can be used. This would be indicated if the
2040 * return value of hugepage_subpool_get_pages() is zero.
2041 * However, if avoid_reserve is specified we still avoid even
2042 * the subpool reservations.
2048 ret
= hugetlb_cgroup_charge_cgroup(idx
, pages_per_huge_page(h
), &h_cg
);
2050 goto out_subpool_put
;
2052 spin_lock(&hugetlb_lock
);
2054 * glb_chg is passed to indicate whether or not a page must be taken
2055 * from the global free pool (global change). gbl_chg == 0 indicates
2056 * a reservation exists for the allocation.
2058 page
= dequeue_huge_page_vma(h
, vma
, addr
, avoid_reserve
, gbl_chg
);
2060 spin_unlock(&hugetlb_lock
);
2061 page
= alloc_buddy_huge_page_with_mpol(h
, vma
, addr
);
2063 goto out_uncharge_cgroup
;
2064 if (!avoid_reserve
&& vma_has_reserves(vma
, gbl_chg
)) {
2065 SetPagePrivate(page
);
2066 h
->resv_huge_pages
--;
2068 spin_lock(&hugetlb_lock
);
2069 list_move(&page
->lru
, &h
->hugepage_activelist
);
2072 hugetlb_cgroup_commit_charge(idx
, pages_per_huge_page(h
), h_cg
, page
);
2073 spin_unlock(&hugetlb_lock
);
2075 set_page_private(page
, (unsigned long)spool
);
2077 map_commit
= vma_commit_reservation(h
, vma
, addr
);
2078 if (unlikely(map_chg
> map_commit
)) {
2080 * The page was added to the reservation map between
2081 * vma_needs_reservation and vma_commit_reservation.
2082 * This indicates a race with hugetlb_reserve_pages.
2083 * Adjust for the subpool count incremented above AND
2084 * in hugetlb_reserve_pages for the same page. Also,
2085 * the reservation count added in hugetlb_reserve_pages
2086 * no longer applies.
2090 rsv_adjust
= hugepage_subpool_put_pages(spool
, 1);
2091 hugetlb_acct_memory(h
, -rsv_adjust
);
2095 out_uncharge_cgroup
:
2096 hugetlb_cgroup_uncharge_cgroup(idx
, pages_per_huge_page(h
), h_cg
);
2098 if (map_chg
|| avoid_reserve
)
2099 hugepage_subpool_put_pages(spool
, 1);
2100 vma_end_reservation(h
, vma
, addr
);
2101 return ERR_PTR(-ENOSPC
);
2104 int alloc_bootmem_huge_page(struct hstate
*h
)
2105 __attribute__ ((weak
, alias("__alloc_bootmem_huge_page")));
2106 int __alloc_bootmem_huge_page(struct hstate
*h
)
2108 struct huge_bootmem_page
*m
;
2111 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, &node_states
[N_MEMORY
]) {
2114 addr
= memblock_alloc_try_nid_raw(
2115 huge_page_size(h
), huge_page_size(h
),
2116 0, MEMBLOCK_ALLOC_ACCESSIBLE
, node
);
2119 * Use the beginning of the huge page to store the
2120 * huge_bootmem_page struct (until gather_bootmem
2121 * puts them into the mem_map).
2130 BUG_ON(!IS_ALIGNED(virt_to_phys(m
), huge_page_size(h
)));
2131 /* Put them into a private list first because mem_map is not up yet */
2132 INIT_LIST_HEAD(&m
->list
);
2133 list_add(&m
->list
, &huge_boot_pages
);
2138 static void __init
prep_compound_huge_page(struct page
*page
,
2141 if (unlikely(order
> (MAX_ORDER
- 1)))
2142 prep_compound_gigantic_page(page
, order
);
2144 prep_compound_page(page
, order
);
2147 /* Put bootmem huge pages into the standard lists after mem_map is up */
2148 static void __init
gather_bootmem_prealloc(void)
2150 struct huge_bootmem_page
*m
;
2152 list_for_each_entry(m
, &huge_boot_pages
, list
) {
2153 struct page
*page
= virt_to_page(m
);
2154 struct hstate
*h
= m
->hstate
;
2156 WARN_ON(page_count(page
) != 1);
2157 prep_compound_huge_page(page
, h
->order
);
2158 WARN_ON(PageReserved(page
));
2159 prep_new_huge_page(h
, page
, page_to_nid(page
));
2160 put_page(page
); /* free it into the hugepage allocator */
2163 * If we had gigantic hugepages allocated at boot time, we need
2164 * to restore the 'stolen' pages to totalram_pages in order to
2165 * fix confusing memory reports from free(1) and another
2166 * side-effects, like CommitLimit going negative.
2168 if (hstate_is_gigantic(h
))
2169 adjust_managed_page_count(page
, 1 << h
->order
);
2174 static void __init
hugetlb_hstate_alloc_pages(struct hstate
*h
)
2177 nodemask_t
*node_alloc_noretry
;
2179 if (!hstate_is_gigantic(h
)) {
2181 * Bit mask controlling how hard we retry per-node allocations.
2182 * Ignore errors as lower level routines can deal with
2183 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2184 * time, we are likely in bigger trouble.
2186 node_alloc_noretry
= kmalloc(sizeof(*node_alloc_noretry
),
2189 /* allocations done at boot time */
2190 node_alloc_noretry
= NULL
;
2193 /* bit mask controlling how hard we retry per-node allocations */
2194 if (node_alloc_noretry
)
2195 nodes_clear(*node_alloc_noretry
);
2197 for (i
= 0; i
< h
->max_huge_pages
; ++i
) {
2198 if (hstate_is_gigantic(h
)) {
2199 if (!alloc_bootmem_huge_page(h
))
2201 } else if (!alloc_pool_huge_page(h
,
2202 &node_states
[N_MEMORY
],
2203 node_alloc_noretry
))
2207 if (i
< h
->max_huge_pages
) {
2210 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2211 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2212 h
->max_huge_pages
, buf
, i
);
2213 h
->max_huge_pages
= i
;
2216 kfree(node_alloc_noretry
);
2219 static void __init
hugetlb_init_hstates(void)
2223 for_each_hstate(h
) {
2224 if (minimum_order
> huge_page_order(h
))
2225 minimum_order
= huge_page_order(h
);
2227 /* oversize hugepages were init'ed in early boot */
2228 if (!hstate_is_gigantic(h
))
2229 hugetlb_hstate_alloc_pages(h
);
2231 VM_BUG_ON(minimum_order
== UINT_MAX
);
2234 static void __init
report_hugepages(void)
2238 for_each_hstate(h
) {
2241 string_get_size(huge_page_size(h
), 1, STRING_UNITS_2
, buf
, 32);
2242 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2243 buf
, h
->free_huge_pages
);
2247 #ifdef CONFIG_HIGHMEM
2248 static void try_to_free_low(struct hstate
*h
, unsigned long count
,
2249 nodemask_t
*nodes_allowed
)
2253 if (hstate_is_gigantic(h
))
2256 for_each_node_mask(i
, *nodes_allowed
) {
2257 struct page
*page
, *next
;
2258 struct list_head
*freel
= &h
->hugepage_freelists
[i
];
2259 list_for_each_entry_safe(page
, next
, freel
, lru
) {
2260 if (count
>= h
->nr_huge_pages
)
2262 if (PageHighMem(page
))
2264 list_del(&page
->lru
);
2265 update_and_free_page(h
, page
);
2266 h
->free_huge_pages
--;
2267 h
->free_huge_pages_node
[page_to_nid(page
)]--;
2272 static inline void try_to_free_low(struct hstate
*h
, unsigned long count
,
2273 nodemask_t
*nodes_allowed
)
2279 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2280 * balanced by operating on them in a round-robin fashion.
2281 * Returns 1 if an adjustment was made.
2283 static int adjust_pool_surplus(struct hstate
*h
, nodemask_t
*nodes_allowed
,
2288 VM_BUG_ON(delta
!= -1 && delta
!= 1);
2291 for_each_node_mask_to_alloc(h
, nr_nodes
, node
, nodes_allowed
) {
2292 if (h
->surplus_huge_pages_node
[node
])
2296 for_each_node_mask_to_free(h
, nr_nodes
, node
, nodes_allowed
) {
2297 if (h
->surplus_huge_pages_node
[node
] <
2298 h
->nr_huge_pages_node
[node
])
2305 h
->surplus_huge_pages
+= delta
;
2306 h
->surplus_huge_pages_node
[node
] += delta
;
2310 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2311 static int set_max_huge_pages(struct hstate
*h
, unsigned long count
, int nid
,
2312 nodemask_t
*nodes_allowed
)
2314 unsigned long min_count
, ret
;
2315 NODEMASK_ALLOC(nodemask_t
, node_alloc_noretry
, GFP_KERNEL
);
2318 * Bit mask controlling how hard we retry per-node allocations.
2319 * If we can not allocate the bit mask, do not attempt to allocate
2320 * the requested huge pages.
2322 if (node_alloc_noretry
)
2323 nodes_clear(*node_alloc_noretry
);
2327 spin_lock(&hugetlb_lock
);
2330 * Check for a node specific request.
2331 * Changing node specific huge page count may require a corresponding
2332 * change to the global count. In any case, the passed node mask
2333 * (nodes_allowed) will restrict alloc/free to the specified node.
2335 if (nid
!= NUMA_NO_NODE
) {
2336 unsigned long old_count
= count
;
2338 count
+= h
->nr_huge_pages
- h
->nr_huge_pages_node
[nid
];
2340 * User may have specified a large count value which caused the
2341 * above calculation to overflow. In this case, they wanted
2342 * to allocate as many huge pages as possible. Set count to
2343 * largest possible value to align with their intention.
2345 if (count
< old_count
)
2350 * Gigantic pages runtime allocation depend on the capability for large
2351 * page range allocation.
2352 * If the system does not provide this feature, return an error when
2353 * the user tries to allocate gigantic pages but let the user free the
2354 * boottime allocated gigantic pages.
2356 if (hstate_is_gigantic(h
) && !IS_ENABLED(CONFIG_CONTIG_ALLOC
)) {
2357 if (count
> persistent_huge_pages(h
)) {
2358 spin_unlock(&hugetlb_lock
);
2359 NODEMASK_FREE(node_alloc_noretry
);
2362 /* Fall through to decrease pool */
2366 * Increase the pool size
2367 * First take pages out of surplus state. Then make up the
2368 * remaining difference by allocating fresh huge pages.
2370 * We might race with alloc_surplus_huge_page() here and be unable
2371 * to convert a surplus huge page to a normal huge page. That is
2372 * not critical, though, it just means the overall size of the
2373 * pool might be one hugepage larger than it needs to be, but
2374 * within all the constraints specified by the sysctls.
2376 while (h
->surplus_huge_pages
&& count
> persistent_huge_pages(h
)) {
2377 if (!adjust_pool_surplus(h
, nodes_allowed
, -1))
2381 while (count
> persistent_huge_pages(h
)) {
2383 * If this allocation races such that we no longer need the
2384 * page, free_huge_page will handle it by freeing the page
2385 * and reducing the surplus.
2387 spin_unlock(&hugetlb_lock
);
2389 /* yield cpu to avoid soft lockup */
2392 ret
= alloc_pool_huge_page(h
, nodes_allowed
,
2393 node_alloc_noretry
);
2394 spin_lock(&hugetlb_lock
);
2398 /* Bail for signals. Probably ctrl-c from user */
2399 if (signal_pending(current
))
2404 * Decrease the pool size
2405 * First return free pages to the buddy allocator (being careful
2406 * to keep enough around to satisfy reservations). Then place
2407 * pages into surplus state as needed so the pool will shrink
2408 * to the desired size as pages become free.
2410 * By placing pages into the surplus state independent of the
2411 * overcommit value, we are allowing the surplus pool size to
2412 * exceed overcommit. There are few sane options here. Since
2413 * alloc_surplus_huge_page() is checking the global counter,
2414 * though, we'll note that we're not allowed to exceed surplus
2415 * and won't grow the pool anywhere else. Not until one of the
2416 * sysctls are changed, or the surplus pages go out of use.
2418 min_count
= h
->resv_huge_pages
+ h
->nr_huge_pages
- h
->free_huge_pages
;
2419 min_count
= max(count
, min_count
);
2420 try_to_free_low(h
, min_count
, nodes_allowed
);
2421 while (min_count
< persistent_huge_pages(h
)) {
2422 if (!free_pool_huge_page(h
, nodes_allowed
, 0))
2424 cond_resched_lock(&hugetlb_lock
);
2426 while (count
< persistent_huge_pages(h
)) {
2427 if (!adjust_pool_surplus(h
, nodes_allowed
, 1))
2431 h
->max_huge_pages
= persistent_huge_pages(h
);
2432 spin_unlock(&hugetlb_lock
);
2434 NODEMASK_FREE(node_alloc_noretry
);
2439 #define HSTATE_ATTR_RO(_name) \
2440 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2442 #define HSTATE_ATTR(_name) \
2443 static struct kobj_attribute _name##_attr = \
2444 __ATTR(_name, 0644, _name##_show, _name##_store)
2446 static struct kobject
*hugepages_kobj
;
2447 static struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2449 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
);
2451 static struct hstate
*kobj_to_hstate(struct kobject
*kobj
, int *nidp
)
2455 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2456 if (hstate_kobjs
[i
] == kobj
) {
2458 *nidp
= NUMA_NO_NODE
;
2462 return kobj_to_node_hstate(kobj
, nidp
);
2465 static ssize_t
nr_hugepages_show_common(struct kobject
*kobj
,
2466 struct kobj_attribute
*attr
, char *buf
)
2469 unsigned long nr_huge_pages
;
2472 h
= kobj_to_hstate(kobj
, &nid
);
2473 if (nid
== NUMA_NO_NODE
)
2474 nr_huge_pages
= h
->nr_huge_pages
;
2476 nr_huge_pages
= h
->nr_huge_pages_node
[nid
];
2478 return sprintf(buf
, "%lu\n", nr_huge_pages
);
2481 static ssize_t
__nr_hugepages_store_common(bool obey_mempolicy
,
2482 struct hstate
*h
, int nid
,
2483 unsigned long count
, size_t len
)
2486 nodemask_t nodes_allowed
, *n_mask
;
2488 if (hstate_is_gigantic(h
) && !gigantic_page_runtime_supported())
2491 if (nid
== NUMA_NO_NODE
) {
2493 * global hstate attribute
2495 if (!(obey_mempolicy
&&
2496 init_nodemask_of_mempolicy(&nodes_allowed
)))
2497 n_mask
= &node_states
[N_MEMORY
];
2499 n_mask
= &nodes_allowed
;
2502 * Node specific request. count adjustment happens in
2503 * set_max_huge_pages() after acquiring hugetlb_lock.
2505 init_nodemask_of_node(&nodes_allowed
, nid
);
2506 n_mask
= &nodes_allowed
;
2509 err
= set_max_huge_pages(h
, count
, nid
, n_mask
);
2511 return err
? err
: len
;
2514 static ssize_t
nr_hugepages_store_common(bool obey_mempolicy
,
2515 struct kobject
*kobj
, const char *buf
,
2519 unsigned long count
;
2523 err
= kstrtoul(buf
, 10, &count
);
2527 h
= kobj_to_hstate(kobj
, &nid
);
2528 return __nr_hugepages_store_common(obey_mempolicy
, h
, nid
, count
, len
);
2531 static ssize_t
nr_hugepages_show(struct kobject
*kobj
,
2532 struct kobj_attribute
*attr
, char *buf
)
2534 return nr_hugepages_show_common(kobj
, attr
, buf
);
2537 static ssize_t
nr_hugepages_store(struct kobject
*kobj
,
2538 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2540 return nr_hugepages_store_common(false, kobj
, buf
, len
);
2542 HSTATE_ATTR(nr_hugepages
);
2547 * hstate attribute for optionally mempolicy-based constraint on persistent
2548 * huge page alloc/free.
2550 static ssize_t
nr_hugepages_mempolicy_show(struct kobject
*kobj
,
2551 struct kobj_attribute
*attr
, char *buf
)
2553 return nr_hugepages_show_common(kobj
, attr
, buf
);
2556 static ssize_t
nr_hugepages_mempolicy_store(struct kobject
*kobj
,
2557 struct kobj_attribute
*attr
, const char *buf
, size_t len
)
2559 return nr_hugepages_store_common(true, kobj
, buf
, len
);
2561 HSTATE_ATTR(nr_hugepages_mempolicy
);
2565 static ssize_t
nr_overcommit_hugepages_show(struct kobject
*kobj
,
2566 struct kobj_attribute
*attr
, char *buf
)
2568 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2569 return sprintf(buf
, "%lu\n", h
->nr_overcommit_huge_pages
);
2572 static ssize_t
nr_overcommit_hugepages_store(struct kobject
*kobj
,
2573 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
2576 unsigned long input
;
2577 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2579 if (hstate_is_gigantic(h
))
2582 err
= kstrtoul(buf
, 10, &input
);
2586 spin_lock(&hugetlb_lock
);
2587 h
->nr_overcommit_huge_pages
= input
;
2588 spin_unlock(&hugetlb_lock
);
2592 HSTATE_ATTR(nr_overcommit_hugepages
);
2594 static ssize_t
free_hugepages_show(struct kobject
*kobj
,
2595 struct kobj_attribute
*attr
, char *buf
)
2598 unsigned long free_huge_pages
;
2601 h
= kobj_to_hstate(kobj
, &nid
);
2602 if (nid
== NUMA_NO_NODE
)
2603 free_huge_pages
= h
->free_huge_pages
;
2605 free_huge_pages
= h
->free_huge_pages_node
[nid
];
2607 return sprintf(buf
, "%lu\n", free_huge_pages
);
2609 HSTATE_ATTR_RO(free_hugepages
);
2611 static ssize_t
resv_hugepages_show(struct kobject
*kobj
,
2612 struct kobj_attribute
*attr
, char *buf
)
2614 struct hstate
*h
= kobj_to_hstate(kobj
, NULL
);
2615 return sprintf(buf
, "%lu\n", h
->resv_huge_pages
);
2617 HSTATE_ATTR_RO(resv_hugepages
);
2619 static ssize_t
surplus_hugepages_show(struct kobject
*kobj
,
2620 struct kobj_attribute
*attr
, char *buf
)
2623 unsigned long surplus_huge_pages
;
2626 h
= kobj_to_hstate(kobj
, &nid
);
2627 if (nid
== NUMA_NO_NODE
)
2628 surplus_huge_pages
= h
->surplus_huge_pages
;
2630 surplus_huge_pages
= h
->surplus_huge_pages_node
[nid
];
2632 return sprintf(buf
, "%lu\n", surplus_huge_pages
);
2634 HSTATE_ATTR_RO(surplus_hugepages
);
2636 static struct attribute
*hstate_attrs
[] = {
2637 &nr_hugepages_attr
.attr
,
2638 &nr_overcommit_hugepages_attr
.attr
,
2639 &free_hugepages_attr
.attr
,
2640 &resv_hugepages_attr
.attr
,
2641 &surplus_hugepages_attr
.attr
,
2643 &nr_hugepages_mempolicy_attr
.attr
,
2648 static const struct attribute_group hstate_attr_group
= {
2649 .attrs
= hstate_attrs
,
2652 static int hugetlb_sysfs_add_hstate(struct hstate
*h
, struct kobject
*parent
,
2653 struct kobject
**hstate_kobjs
,
2654 const struct attribute_group
*hstate_attr_group
)
2657 int hi
= hstate_index(h
);
2659 hstate_kobjs
[hi
] = kobject_create_and_add(h
->name
, parent
);
2660 if (!hstate_kobjs
[hi
])
2663 retval
= sysfs_create_group(hstate_kobjs
[hi
], hstate_attr_group
);
2665 kobject_put(hstate_kobjs
[hi
]);
2670 static void __init
hugetlb_sysfs_init(void)
2675 hugepages_kobj
= kobject_create_and_add("hugepages", mm_kobj
);
2676 if (!hugepages_kobj
)
2679 for_each_hstate(h
) {
2680 err
= hugetlb_sysfs_add_hstate(h
, hugepages_kobj
,
2681 hstate_kobjs
, &hstate_attr_group
);
2683 pr_err("Hugetlb: Unable to add hstate %s", h
->name
);
2690 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2691 * with node devices in node_devices[] using a parallel array. The array
2692 * index of a node device or _hstate == node id.
2693 * This is here to avoid any static dependency of the node device driver, in
2694 * the base kernel, on the hugetlb module.
2696 struct node_hstate
{
2697 struct kobject
*hugepages_kobj
;
2698 struct kobject
*hstate_kobjs
[HUGE_MAX_HSTATE
];
2700 static struct node_hstate node_hstates
[MAX_NUMNODES
];
2703 * A subset of global hstate attributes for node devices
2705 static struct attribute
*per_node_hstate_attrs
[] = {
2706 &nr_hugepages_attr
.attr
,
2707 &free_hugepages_attr
.attr
,
2708 &surplus_hugepages_attr
.attr
,
2712 static const struct attribute_group per_node_hstate_attr_group
= {
2713 .attrs
= per_node_hstate_attrs
,
2717 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2718 * Returns node id via non-NULL nidp.
2720 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2724 for (nid
= 0; nid
< nr_node_ids
; nid
++) {
2725 struct node_hstate
*nhs
= &node_hstates
[nid
];
2727 for (i
= 0; i
< HUGE_MAX_HSTATE
; i
++)
2728 if (nhs
->hstate_kobjs
[i
] == kobj
) {
2740 * Unregister hstate attributes from a single node device.
2741 * No-op if no hstate attributes attached.
2743 static void hugetlb_unregister_node(struct node
*node
)
2746 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2748 if (!nhs
->hugepages_kobj
)
2749 return; /* no hstate attributes */
2751 for_each_hstate(h
) {
2752 int idx
= hstate_index(h
);
2753 if (nhs
->hstate_kobjs
[idx
]) {
2754 kobject_put(nhs
->hstate_kobjs
[idx
]);
2755 nhs
->hstate_kobjs
[idx
] = NULL
;
2759 kobject_put(nhs
->hugepages_kobj
);
2760 nhs
->hugepages_kobj
= NULL
;
2765 * Register hstate attributes for a single node device.
2766 * No-op if attributes already registered.
2768 static void hugetlb_register_node(struct node
*node
)
2771 struct node_hstate
*nhs
= &node_hstates
[node
->dev
.id
];
2774 if (nhs
->hugepages_kobj
)
2775 return; /* already allocated */
2777 nhs
->hugepages_kobj
= kobject_create_and_add("hugepages",
2779 if (!nhs
->hugepages_kobj
)
2782 for_each_hstate(h
) {
2783 err
= hugetlb_sysfs_add_hstate(h
, nhs
->hugepages_kobj
,
2785 &per_node_hstate_attr_group
);
2787 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2788 h
->name
, node
->dev
.id
);
2789 hugetlb_unregister_node(node
);
2796 * hugetlb init time: register hstate attributes for all registered node
2797 * devices of nodes that have memory. All on-line nodes should have
2798 * registered their associated device by this time.
2800 static void __init
hugetlb_register_all_nodes(void)
2804 for_each_node_state(nid
, N_MEMORY
) {
2805 struct node
*node
= node_devices
[nid
];
2806 if (node
->dev
.id
== nid
)
2807 hugetlb_register_node(node
);
2811 * Let the node device driver know we're here so it can
2812 * [un]register hstate attributes on node hotplug.
2814 register_hugetlbfs_with_node(hugetlb_register_node
,
2815 hugetlb_unregister_node
);
2817 #else /* !CONFIG_NUMA */
2819 static struct hstate
*kobj_to_node_hstate(struct kobject
*kobj
, int *nidp
)
2827 static void hugetlb_register_all_nodes(void) { }
2831 static int __init
hugetlb_init(void)
2835 if (!hugepages_supported())
2838 if (!size_to_hstate(default_hstate_size
)) {
2839 if (default_hstate_size
!= 0) {
2840 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
2841 default_hstate_size
, HPAGE_SIZE
);
2844 default_hstate_size
= HPAGE_SIZE
;
2845 if (!size_to_hstate(default_hstate_size
))
2846 hugetlb_add_hstate(HUGETLB_PAGE_ORDER
);
2848 default_hstate_idx
= hstate_index(size_to_hstate(default_hstate_size
));
2849 if (default_hstate_max_huge_pages
) {
2850 if (!default_hstate
.max_huge_pages
)
2851 default_hstate
.max_huge_pages
= default_hstate_max_huge_pages
;
2854 hugetlb_init_hstates();
2855 gather_bootmem_prealloc();
2858 hugetlb_sysfs_init();
2859 hugetlb_register_all_nodes();
2860 hugetlb_cgroup_file_init();
2863 num_fault_mutexes
= roundup_pow_of_two(8 * num_possible_cpus());
2865 num_fault_mutexes
= 1;
2867 hugetlb_fault_mutex_table
=
2868 kmalloc_array(num_fault_mutexes
, sizeof(struct mutex
),
2870 BUG_ON(!hugetlb_fault_mutex_table
);
2872 for (i
= 0; i
< num_fault_mutexes
; i
++)
2873 mutex_init(&hugetlb_fault_mutex_table
[i
]);
2876 subsys_initcall(hugetlb_init
);
2878 /* Should be called on processing a hugepagesz=... option */
2879 void __init
hugetlb_bad_size(void)
2881 parsed_valid_hugepagesz
= false;
2884 void __init
hugetlb_add_hstate(unsigned int order
)
2889 if (size_to_hstate(PAGE_SIZE
<< order
)) {
2890 pr_warn("hugepagesz= specified twice, ignoring\n");
2893 BUG_ON(hugetlb_max_hstate
>= HUGE_MAX_HSTATE
);
2895 h
= &hstates
[hugetlb_max_hstate
++];
2897 h
->mask
= ~((1ULL << (order
+ PAGE_SHIFT
)) - 1);
2898 h
->nr_huge_pages
= 0;
2899 h
->free_huge_pages
= 0;
2900 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
2901 INIT_LIST_HEAD(&h
->hugepage_freelists
[i
]);
2902 INIT_LIST_HEAD(&h
->hugepage_activelist
);
2903 h
->next_nid_to_alloc
= first_memory_node
;
2904 h
->next_nid_to_free
= first_memory_node
;
2905 snprintf(h
->name
, HSTATE_NAME_LEN
, "hugepages-%lukB",
2906 huge_page_size(h
)/1024);
2911 static int __init
hugetlb_nrpages_setup(char *s
)
2914 static unsigned long *last_mhp
;
2916 if (!parsed_valid_hugepagesz
) {
2917 pr_warn("hugepages = %s preceded by "
2918 "an unsupported hugepagesz, ignoring\n", s
);
2919 parsed_valid_hugepagesz
= true;
2923 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2924 * so this hugepages= parameter goes to the "default hstate".
2926 else if (!hugetlb_max_hstate
)
2927 mhp
= &default_hstate_max_huge_pages
;
2929 mhp
= &parsed_hstate
->max_huge_pages
;
2931 if (mhp
== last_mhp
) {
2932 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2936 if (sscanf(s
, "%lu", mhp
) <= 0)
2940 * Global state is always initialized later in hugetlb_init.
2941 * But we need to allocate >= MAX_ORDER hstates here early to still
2942 * use the bootmem allocator.
2944 if (hugetlb_max_hstate
&& parsed_hstate
->order
>= MAX_ORDER
)
2945 hugetlb_hstate_alloc_pages(parsed_hstate
);
2951 __setup("hugepages=", hugetlb_nrpages_setup
);
2953 static int __init
hugetlb_default_setup(char *s
)
2955 default_hstate_size
= memparse(s
, &s
);
2958 __setup("default_hugepagesz=", hugetlb_default_setup
);
2960 static unsigned int cpuset_mems_nr(unsigned int *array
)
2963 unsigned int nr
= 0;
2965 for_each_node_mask(node
, cpuset_current_mems_allowed
)
2971 #ifdef CONFIG_SYSCTL
2972 static int hugetlb_sysctl_handler_common(bool obey_mempolicy
,
2973 struct ctl_table
*table
, int write
,
2974 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2976 struct hstate
*h
= &default_hstate
;
2977 unsigned long tmp
= h
->max_huge_pages
;
2980 if (!hugepages_supported())
2984 table
->maxlen
= sizeof(unsigned long);
2985 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
2990 ret
= __nr_hugepages_store_common(obey_mempolicy
, h
,
2991 NUMA_NO_NODE
, tmp
, *length
);
2996 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
2997 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3000 return hugetlb_sysctl_handler_common(false, table
, write
,
3001 buffer
, length
, ppos
);
3005 int hugetlb_mempolicy_sysctl_handler(struct ctl_table
*table
, int write
,
3006 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
3008 return hugetlb_sysctl_handler_common(true, table
, write
,
3009 buffer
, length
, ppos
);
3011 #endif /* CONFIG_NUMA */
3013 int hugetlb_overcommit_handler(struct ctl_table
*table
, int write
,
3014 void __user
*buffer
,
3015 size_t *length
, loff_t
*ppos
)
3017 struct hstate
*h
= &default_hstate
;
3021 if (!hugepages_supported())
3024 tmp
= h
->nr_overcommit_huge_pages
;
3026 if (write
&& hstate_is_gigantic(h
))
3030 table
->maxlen
= sizeof(unsigned long);
3031 ret
= proc_doulongvec_minmax(table
, write
, buffer
, length
, ppos
);
3036 spin_lock(&hugetlb_lock
);
3037 h
->nr_overcommit_huge_pages
= tmp
;
3038 spin_unlock(&hugetlb_lock
);
3044 #endif /* CONFIG_SYSCTL */
3046 void hugetlb_report_meminfo(struct seq_file
*m
)
3049 unsigned long total
= 0;
3051 if (!hugepages_supported())
3054 for_each_hstate(h
) {
3055 unsigned long count
= h
->nr_huge_pages
;
3057 total
+= (PAGE_SIZE
<< huge_page_order(h
)) * count
;
3059 if (h
== &default_hstate
)
3061 "HugePages_Total: %5lu\n"
3062 "HugePages_Free: %5lu\n"
3063 "HugePages_Rsvd: %5lu\n"
3064 "HugePages_Surp: %5lu\n"
3065 "Hugepagesize: %8lu kB\n",
3069 h
->surplus_huge_pages
,
3070 (PAGE_SIZE
<< huge_page_order(h
)) / 1024);
3073 seq_printf(m
, "Hugetlb: %8lu kB\n", total
/ 1024);
3076 int hugetlb_report_node_meminfo(int nid
, char *buf
)
3078 struct hstate
*h
= &default_hstate
;
3079 if (!hugepages_supported())
3082 "Node %d HugePages_Total: %5u\n"
3083 "Node %d HugePages_Free: %5u\n"
3084 "Node %d HugePages_Surp: %5u\n",
3085 nid
, h
->nr_huge_pages_node
[nid
],
3086 nid
, h
->free_huge_pages_node
[nid
],
3087 nid
, h
->surplus_huge_pages_node
[nid
]);
3090 void hugetlb_show_meminfo(void)
3095 if (!hugepages_supported())
3098 for_each_node_state(nid
, N_MEMORY
)
3100 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3102 h
->nr_huge_pages_node
[nid
],
3103 h
->free_huge_pages_node
[nid
],
3104 h
->surplus_huge_pages_node
[nid
],
3105 1UL << (huge_page_order(h
) + PAGE_SHIFT
- 10));
3108 void hugetlb_report_usage(struct seq_file
*m
, struct mm_struct
*mm
)
3110 seq_printf(m
, "HugetlbPages:\t%8lu kB\n",
3111 atomic_long_read(&mm
->hugetlb_usage
) << (PAGE_SHIFT
- 10));
3114 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3115 unsigned long hugetlb_total_pages(void)
3118 unsigned long nr_total_pages
= 0;
3121 nr_total_pages
+= h
->nr_huge_pages
* pages_per_huge_page(h
);
3122 return nr_total_pages
;
3125 static int hugetlb_acct_memory(struct hstate
*h
, long delta
)
3129 spin_lock(&hugetlb_lock
);
3131 * When cpuset is configured, it breaks the strict hugetlb page
3132 * reservation as the accounting is done on a global variable. Such
3133 * reservation is completely rubbish in the presence of cpuset because
3134 * the reservation is not checked against page availability for the
3135 * current cpuset. Application can still potentially OOM'ed by kernel
3136 * with lack of free htlb page in cpuset that the task is in.
3137 * Attempt to enforce strict accounting with cpuset is almost
3138 * impossible (or too ugly) because cpuset is too fluid that
3139 * task or memory node can be dynamically moved between cpusets.
3141 * The change of semantics for shared hugetlb mapping with cpuset is
3142 * undesirable. However, in order to preserve some of the semantics,
3143 * we fall back to check against current free page availability as
3144 * a best attempt and hopefully to minimize the impact of changing
3145 * semantics that cpuset has.
3148 if (gather_surplus_pages(h
, delta
) < 0)
3151 if (delta
> cpuset_mems_nr(h
->free_huge_pages_node
)) {
3152 return_unused_surplus_pages(h
, delta
);
3159 return_unused_surplus_pages(h
, (unsigned long) -delta
);
3162 spin_unlock(&hugetlb_lock
);
3166 static void hugetlb_vm_op_open(struct vm_area_struct
*vma
)
3168 struct resv_map
*resv
= vma_resv_map(vma
);
3171 * This new VMA should share its siblings reservation map if present.
3172 * The VMA will only ever have a valid reservation map pointer where
3173 * it is being copied for another still existing VMA. As that VMA
3174 * has a reference to the reservation map it cannot disappear until
3175 * after this open call completes. It is therefore safe to take a
3176 * new reference here without additional locking.
3178 if (resv
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3179 kref_get(&resv
->refs
);
3182 static void hugetlb_vm_op_close(struct vm_area_struct
*vma
)
3184 struct hstate
*h
= hstate_vma(vma
);
3185 struct resv_map
*resv
= vma_resv_map(vma
);
3186 struct hugepage_subpool
*spool
= subpool_vma(vma
);
3187 unsigned long reserve
, start
, end
;
3190 if (!resv
|| !is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
3193 start
= vma_hugecache_offset(h
, vma
, vma
->vm_start
);
3194 end
= vma_hugecache_offset(h
, vma
, vma
->vm_end
);
3196 reserve
= (end
- start
) - region_count(resv
, start
, end
);
3198 kref_put(&resv
->refs
, resv_map_release
);
3202 * Decrement reserve counts. The global reserve count may be
3203 * adjusted if the subpool has a minimum size.
3205 gbl_reserve
= hugepage_subpool_put_pages(spool
, reserve
);
3206 hugetlb_acct_memory(h
, -gbl_reserve
);
3210 static int hugetlb_vm_op_split(struct vm_area_struct
*vma
, unsigned long addr
)
3212 if (addr
& ~(huge_page_mask(hstate_vma(vma
))))
3217 static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct
*vma
)
3219 struct hstate
*hstate
= hstate_vma(vma
);
3221 return 1UL << huge_page_shift(hstate
);
3225 * We cannot handle pagefaults against hugetlb pages at all. They cause
3226 * handle_mm_fault() to try to instantiate regular-sized pages in the
3227 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3230 static vm_fault_t
hugetlb_vm_op_fault(struct vm_fault
*vmf
)
3237 * When a new function is introduced to vm_operations_struct and added
3238 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3239 * This is because under System V memory model, mappings created via
3240 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3241 * their original vm_ops are overwritten with shm_vm_ops.
3243 const struct vm_operations_struct hugetlb_vm_ops
= {
3244 .fault
= hugetlb_vm_op_fault
,
3245 .open
= hugetlb_vm_op_open
,
3246 .close
= hugetlb_vm_op_close
,
3247 .split
= hugetlb_vm_op_split
,
3248 .pagesize
= hugetlb_vm_op_pagesize
,
3251 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
3257 entry
= huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page
,
3258 vma
->vm_page_prot
)));
3260 entry
= huge_pte_wrprotect(mk_huge_pte(page
,
3261 vma
->vm_page_prot
));
3263 entry
= pte_mkyoung(entry
);
3264 entry
= pte_mkhuge(entry
);
3265 entry
= arch_make_huge_pte(entry
, vma
, page
, writable
);
3270 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
3271 unsigned long address
, pte_t
*ptep
)
3275 entry
= huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep
)));
3276 if (huge_ptep_set_access_flags(vma
, address
, ptep
, entry
, 1))
3277 update_mmu_cache(vma
, address
, ptep
);
3280 bool is_hugetlb_entry_migration(pte_t pte
)
3284 if (huge_pte_none(pte
) || pte_present(pte
))
3286 swp
= pte_to_swp_entry(pte
);
3287 if (non_swap_entry(swp
) && is_migration_entry(swp
))
3293 static int is_hugetlb_entry_hwpoisoned(pte_t pte
)
3297 if (huge_pte_none(pte
) || pte_present(pte
))
3299 swp
= pte_to_swp_entry(pte
);
3300 if (non_swap_entry(swp
) && is_hwpoison_entry(swp
))
3306 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
3307 struct vm_area_struct
*vma
)
3309 pte_t
*src_pte
, *dst_pte
, entry
, dst_entry
;
3310 struct page
*ptepage
;
3313 struct hstate
*h
= hstate_vma(vma
);
3314 unsigned long sz
= huge_page_size(h
);
3315 struct mmu_notifier_range range
;
3318 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
3321 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, src
,
3324 mmu_notifier_invalidate_range_start(&range
);
3327 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= sz
) {
3328 spinlock_t
*src_ptl
, *dst_ptl
;
3329 src_pte
= huge_pte_offset(src
, addr
, sz
);
3332 dst_pte
= huge_pte_alloc(dst
, addr
, sz
);
3339 * If the pagetables are shared don't copy or take references.
3340 * dst_pte == src_pte is the common case of src/dest sharing.
3342 * However, src could have 'unshared' and dst shares with
3343 * another vma. If dst_pte !none, this implies sharing.
3344 * Check here before taking page table lock, and once again
3345 * after taking the lock below.
3347 dst_entry
= huge_ptep_get(dst_pte
);
3348 if ((dst_pte
== src_pte
) || !huge_pte_none(dst_entry
))
3351 dst_ptl
= huge_pte_lock(h
, dst
, dst_pte
);
3352 src_ptl
= huge_pte_lockptr(h
, src
, src_pte
);
3353 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
3354 entry
= huge_ptep_get(src_pte
);
3355 dst_entry
= huge_ptep_get(dst_pte
);
3356 if (huge_pte_none(entry
) || !huge_pte_none(dst_entry
)) {
3358 * Skip if src entry none. Also, skip in the
3359 * unlikely case dst entry !none as this implies
3360 * sharing with another vma.
3363 } else if (unlikely(is_hugetlb_entry_migration(entry
) ||
3364 is_hugetlb_entry_hwpoisoned(entry
))) {
3365 swp_entry_t swp_entry
= pte_to_swp_entry(entry
);
3367 if (is_write_migration_entry(swp_entry
) && cow
) {
3369 * COW mappings require pages in both
3370 * parent and child to be set to read.
3372 make_migration_entry_read(&swp_entry
);
3373 entry
= swp_entry_to_pte(swp_entry
);
3374 set_huge_swap_pte_at(src
, addr
, src_pte
,
3377 set_huge_swap_pte_at(dst
, addr
, dst_pte
, entry
, sz
);
3381 * No need to notify as we are downgrading page
3382 * table protection not changing it to point
3385 * See Documentation/vm/mmu_notifier.rst
3387 huge_ptep_set_wrprotect(src
, addr
, src_pte
);
3389 entry
= huge_ptep_get(src_pte
);
3390 ptepage
= pte_page(entry
);
3392 page_dup_rmap(ptepage
, true);
3393 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
3394 hugetlb_count_add(pages_per_huge_page(h
), dst
);
3396 spin_unlock(src_ptl
);
3397 spin_unlock(dst_ptl
);
3401 mmu_notifier_invalidate_range_end(&range
);
3406 void __unmap_hugepage_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
3407 unsigned long start
, unsigned long end
,
3408 struct page
*ref_page
)
3410 struct mm_struct
*mm
= vma
->vm_mm
;
3411 unsigned long address
;
3416 struct hstate
*h
= hstate_vma(vma
);
3417 unsigned long sz
= huge_page_size(h
);
3418 struct mmu_notifier_range range
;
3420 WARN_ON(!is_vm_hugetlb_page(vma
));
3421 BUG_ON(start
& ~huge_page_mask(h
));
3422 BUG_ON(end
& ~huge_page_mask(h
));
3425 * This is a hugetlb vma, all the pte entries should point
3428 tlb_change_page_size(tlb
, sz
);
3429 tlb_start_vma(tlb
, vma
);
3432 * If sharing possible, alert mmu notifiers of worst case.
3434 mmu_notifier_range_init(&range
, MMU_NOTIFY_UNMAP
, 0, vma
, mm
, start
,
3436 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
3437 mmu_notifier_invalidate_range_start(&range
);
3439 for (; address
< end
; address
+= sz
) {
3440 ptep
= huge_pte_offset(mm
, address
, sz
);
3444 ptl
= huge_pte_lock(h
, mm
, ptep
);
3445 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
3448 * We just unmapped a page of PMDs by clearing a PUD.
3449 * The caller's TLB flush range should cover this area.
3454 pte
= huge_ptep_get(ptep
);
3455 if (huge_pte_none(pte
)) {
3461 * Migrating hugepage or HWPoisoned hugepage is already
3462 * unmapped and its refcount is dropped, so just clear pte here.
3464 if (unlikely(!pte_present(pte
))) {
3465 huge_pte_clear(mm
, address
, ptep
, sz
);
3470 page
= pte_page(pte
);
3472 * If a reference page is supplied, it is because a specific
3473 * page is being unmapped, not a range. Ensure the page we
3474 * are about to unmap is the actual page of interest.
3477 if (page
!= ref_page
) {
3482 * Mark the VMA as having unmapped its page so that
3483 * future faults in this VMA will fail rather than
3484 * looking like data was lost
3486 set_vma_resv_flags(vma
, HPAGE_RESV_UNMAPPED
);
3489 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
3490 tlb_remove_huge_tlb_entry(h
, tlb
, ptep
, address
);
3491 if (huge_pte_dirty(pte
))
3492 set_page_dirty(page
);
3494 hugetlb_count_sub(pages_per_huge_page(h
), mm
);
3495 page_remove_rmap(page
, true);
3498 tlb_remove_page_size(tlb
, page
, huge_page_size(h
));
3500 * Bail out after unmapping reference page if supplied
3505 mmu_notifier_invalidate_range_end(&range
);
3506 tlb_end_vma(tlb
, vma
);
3509 void __unmap_hugepage_range_final(struct mmu_gather
*tlb
,
3510 struct vm_area_struct
*vma
, unsigned long start
,
3511 unsigned long end
, struct page
*ref_page
)
3513 __unmap_hugepage_range(tlb
, vma
, start
, end
, ref_page
);
3516 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3517 * test will fail on a vma being torn down, and not grab a page table
3518 * on its way out. We're lucky that the flag has such an appropriate
3519 * name, and can in fact be safely cleared here. We could clear it
3520 * before the __unmap_hugepage_range above, but all that's necessary
3521 * is to clear it before releasing the i_mmap_rwsem. This works
3522 * because in the context this is called, the VMA is about to be
3523 * destroyed and the i_mmap_rwsem is held.
3525 vma
->vm_flags
&= ~VM_MAYSHARE
;
3528 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
3529 unsigned long end
, struct page
*ref_page
)
3531 struct mm_struct
*mm
;
3532 struct mmu_gather tlb
;
3533 unsigned long tlb_start
= start
;
3534 unsigned long tlb_end
= end
;
3537 * If shared PMDs were possibly used within this vma range, adjust
3538 * start/end for worst case tlb flushing.
3539 * Note that we can not be sure if PMDs are shared until we try to
3540 * unmap pages. However, we want to make sure TLB flushing covers
3541 * the largest possible range.
3543 adjust_range_if_pmd_sharing_possible(vma
, &tlb_start
, &tlb_end
);
3547 tlb_gather_mmu(&tlb
, mm
, tlb_start
, tlb_end
);
3548 __unmap_hugepage_range(&tlb
, vma
, start
, end
, ref_page
);
3549 tlb_finish_mmu(&tlb
, tlb_start
, tlb_end
);
3553 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3554 * mappping it owns the reserve page for. The intention is to unmap the page
3555 * from other VMAs and let the children be SIGKILLed if they are faulting the
3558 static void unmap_ref_private(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3559 struct page
*page
, unsigned long address
)
3561 struct hstate
*h
= hstate_vma(vma
);
3562 struct vm_area_struct
*iter_vma
;
3563 struct address_space
*mapping
;
3567 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3568 * from page cache lookup which is in HPAGE_SIZE units.
3570 address
= address
& huge_page_mask(h
);
3571 pgoff
= ((address
- vma
->vm_start
) >> PAGE_SHIFT
) +
3573 mapping
= vma
->vm_file
->f_mapping
;
3576 * Take the mapping lock for the duration of the table walk. As
3577 * this mapping should be shared between all the VMAs,
3578 * __unmap_hugepage_range() is called as the lock is already held
3580 i_mmap_lock_write(mapping
);
3581 vma_interval_tree_foreach(iter_vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
3582 /* Do not unmap the current VMA */
3583 if (iter_vma
== vma
)
3587 * Shared VMAs have their own reserves and do not affect
3588 * MAP_PRIVATE accounting but it is possible that a shared
3589 * VMA is using the same page so check and skip such VMAs.
3591 if (iter_vma
->vm_flags
& VM_MAYSHARE
)
3595 * Unmap the page from other VMAs without their own reserves.
3596 * They get marked to be SIGKILLed if they fault in these
3597 * areas. This is because a future no-page fault on this VMA
3598 * could insert a zeroed page instead of the data existing
3599 * from the time of fork. This would look like data corruption
3601 if (!is_vma_resv_set(iter_vma
, HPAGE_RESV_OWNER
))
3602 unmap_hugepage_range(iter_vma
, address
,
3603 address
+ huge_page_size(h
), page
);
3605 i_mmap_unlock_write(mapping
);
3609 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3610 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3611 * cannot race with other handlers or page migration.
3612 * Keep the pte_same checks anyway to make transition from the mutex easier.
3614 static vm_fault_t
hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3615 unsigned long address
, pte_t
*ptep
,
3616 struct page
*pagecache_page
, spinlock_t
*ptl
)
3619 struct hstate
*h
= hstate_vma(vma
);
3620 struct page
*old_page
, *new_page
;
3621 int outside_reserve
= 0;
3623 unsigned long haddr
= address
& huge_page_mask(h
);
3624 struct mmu_notifier_range range
;
3626 pte
= huge_ptep_get(ptep
);
3627 old_page
= pte_page(pte
);
3630 /* If no-one else is actually using this page, avoid the copy
3631 * and just make the page writable */
3632 if (page_mapcount(old_page
) == 1 && PageAnon(old_page
)) {
3633 page_move_anon_rmap(old_page
, vma
);
3634 set_huge_ptep_writable(vma
, haddr
, ptep
);
3639 * If the process that created a MAP_PRIVATE mapping is about to
3640 * perform a COW due to a shared page count, attempt to satisfy
3641 * the allocation without using the existing reserves. The pagecache
3642 * page is used to determine if the reserve at this address was
3643 * consumed or not. If reserves were used, a partial faulted mapping
3644 * at the time of fork() could consume its reserves on COW instead
3645 * of the full address range.
3647 if (is_vma_resv_set(vma
, HPAGE_RESV_OWNER
) &&
3648 old_page
!= pagecache_page
)
3649 outside_reserve
= 1;
3654 * Drop page table lock as buddy allocator may be called. It will
3655 * be acquired again before returning to the caller, as expected.
3658 new_page
= alloc_huge_page(vma
, haddr
, outside_reserve
);
3660 if (IS_ERR(new_page
)) {
3662 * If a process owning a MAP_PRIVATE mapping fails to COW,
3663 * it is due to references held by a child and an insufficient
3664 * huge page pool. To guarantee the original mappers
3665 * reliability, unmap the page from child processes. The child
3666 * may get SIGKILLed if it later faults.
3668 if (outside_reserve
) {
3670 BUG_ON(huge_pte_none(pte
));
3671 unmap_ref_private(mm
, vma
, old_page
, haddr
);
3672 BUG_ON(huge_pte_none(pte
));
3674 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3676 pte_same(huge_ptep_get(ptep
), pte
)))
3677 goto retry_avoidcopy
;
3679 * race occurs while re-acquiring page table
3680 * lock, and our job is done.
3685 ret
= vmf_error(PTR_ERR(new_page
));
3686 goto out_release_old
;
3690 * When the original hugepage is shared one, it does not have
3691 * anon_vma prepared.
3693 if (unlikely(anon_vma_prepare(vma
))) {
3695 goto out_release_all
;
3698 copy_user_huge_page(new_page
, old_page
, address
, vma
,
3699 pages_per_huge_page(h
));
3700 __SetPageUptodate(new_page
);
3702 mmu_notifier_range_init(&range
, MMU_NOTIFY_CLEAR
, 0, vma
, mm
, haddr
,
3703 haddr
+ huge_page_size(h
));
3704 mmu_notifier_invalidate_range_start(&range
);
3707 * Retake the page table lock to check for racing updates
3708 * before the page tables are altered
3711 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
3712 if (likely(ptep
&& pte_same(huge_ptep_get(ptep
), pte
))) {
3713 ClearPagePrivate(new_page
);
3716 huge_ptep_clear_flush(vma
, haddr
, ptep
);
3717 mmu_notifier_invalidate_range(mm
, range
.start
, range
.end
);
3718 set_huge_pte_at(mm
, haddr
, ptep
,
3719 make_huge_pte(vma
, new_page
, 1));
3720 page_remove_rmap(old_page
, true);
3721 hugepage_add_new_anon_rmap(new_page
, vma
, haddr
);
3722 set_page_huge_active(new_page
);
3723 /* Make the old page be freed below */
3724 new_page
= old_page
;
3727 mmu_notifier_invalidate_range_end(&range
);
3729 restore_reserve_on_error(h
, vma
, haddr
, new_page
);
3734 spin_lock(ptl
); /* Caller expects lock to be held */
3738 /* Return the pagecache page at a given address within a VMA */
3739 static struct page
*hugetlbfs_pagecache_page(struct hstate
*h
,
3740 struct vm_area_struct
*vma
, unsigned long address
)
3742 struct address_space
*mapping
;
3745 mapping
= vma
->vm_file
->f_mapping
;
3746 idx
= vma_hugecache_offset(h
, vma
, address
);
3748 return find_lock_page(mapping
, idx
);
3752 * Return whether there is a pagecache page to back given address within VMA.
3753 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3755 static bool hugetlbfs_pagecache_present(struct hstate
*h
,
3756 struct vm_area_struct
*vma
, unsigned long address
)
3758 struct address_space
*mapping
;
3762 mapping
= vma
->vm_file
->f_mapping
;
3763 idx
= vma_hugecache_offset(h
, vma
, address
);
3765 page
= find_get_page(mapping
, idx
);
3768 return page
!= NULL
;
3771 int huge_add_to_page_cache(struct page
*page
, struct address_space
*mapping
,
3774 struct inode
*inode
= mapping
->host
;
3775 struct hstate
*h
= hstate_inode(inode
);
3776 int err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
3780 ClearPagePrivate(page
);
3783 * set page dirty so that it will not be removed from cache/file
3784 * by non-hugetlbfs specific code paths.
3786 set_page_dirty(page
);
3788 spin_lock(&inode
->i_lock
);
3789 inode
->i_blocks
+= blocks_per_huge_page(h
);
3790 spin_unlock(&inode
->i_lock
);
3794 static vm_fault_t
hugetlb_no_page(struct mm_struct
*mm
,
3795 struct vm_area_struct
*vma
,
3796 struct address_space
*mapping
, pgoff_t idx
,
3797 unsigned long address
, pte_t
*ptep
, unsigned int flags
)
3799 struct hstate
*h
= hstate_vma(vma
);
3800 vm_fault_t ret
= VM_FAULT_SIGBUS
;
3806 unsigned long haddr
= address
& huge_page_mask(h
);
3807 bool new_page
= false;
3810 * Currently, we are forced to kill the process in the event the
3811 * original mapper has unmapped pages from the child due to a failed
3812 * COW. Warn that such a situation has occurred as it may not be obvious
3814 if (is_vma_resv_set(vma
, HPAGE_RESV_UNMAPPED
)) {
3815 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3821 * Use page lock to guard against racing truncation
3822 * before we get page_table_lock.
3825 page
= find_lock_page(mapping
, idx
);
3827 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3832 * Check for page in userfault range
3834 if (userfaultfd_missing(vma
)) {
3836 struct vm_fault vmf
= {
3841 * Hard to debug if it ends up being
3842 * used by a callee that assumes
3843 * something about the other
3844 * uninitialized fields... same as in
3850 * hugetlb_fault_mutex must be dropped before
3851 * handling userfault. Reacquire after handling
3852 * fault to make calling code simpler.
3854 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
3855 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
3856 ret
= handle_userfault(&vmf
, VM_UFFD_MISSING
);
3857 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
3861 page
= alloc_huge_page(vma
, haddr
, 0);
3864 * Returning error will result in faulting task being
3865 * sent SIGBUS. The hugetlb fault mutex prevents two
3866 * tasks from racing to fault in the same page which
3867 * could result in false unable to allocate errors.
3868 * Page migration does not take the fault mutex, but
3869 * does a clear then write of pte's under page table
3870 * lock. Page fault code could race with migration,
3871 * notice the clear pte and try to allocate a page
3872 * here. Before returning error, get ptl and make
3873 * sure there really is no pte entry.
3875 ptl
= huge_pte_lock(h
, mm
, ptep
);
3876 if (!huge_pte_none(huge_ptep_get(ptep
))) {
3882 ret
= vmf_error(PTR_ERR(page
));
3885 clear_huge_page(page
, address
, pages_per_huge_page(h
));
3886 __SetPageUptodate(page
);
3889 if (vma
->vm_flags
& VM_MAYSHARE
) {
3890 int err
= huge_add_to_page_cache(page
, mapping
, idx
);
3899 if (unlikely(anon_vma_prepare(vma
))) {
3901 goto backout_unlocked
;
3907 * If memory error occurs between mmap() and fault, some process
3908 * don't have hwpoisoned swap entry for errored virtual address.
3909 * So we need to block hugepage fault by PG_hwpoison bit check.
3911 if (unlikely(PageHWPoison(page
))) {
3912 ret
= VM_FAULT_HWPOISON
|
3913 VM_FAULT_SET_HINDEX(hstate_index(h
));
3914 goto backout_unlocked
;
3919 * If we are going to COW a private mapping later, we examine the
3920 * pending reservations for this page now. This will ensure that
3921 * any allocations necessary to record that reservation occur outside
3924 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3925 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
3927 goto backout_unlocked
;
3929 /* Just decrements count, does not deallocate */
3930 vma_end_reservation(h
, vma
, haddr
);
3933 ptl
= huge_pte_lock(h
, mm
, ptep
);
3934 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
3939 if (!huge_pte_none(huge_ptep_get(ptep
)))
3943 ClearPagePrivate(page
);
3944 hugepage_add_new_anon_rmap(page
, vma
, haddr
);
3946 page_dup_rmap(page
, true);
3947 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
3948 && (vma
->vm_flags
& VM_SHARED
)));
3949 set_huge_pte_at(mm
, haddr
, ptep
, new_pte
);
3951 hugetlb_count_add(pages_per_huge_page(h
), mm
);
3952 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3953 /* Optimization, do the COW without a second fault */
3954 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, page
, ptl
);
3960 * Only make newly allocated pages active. Existing pages found
3961 * in the pagecache could be !page_huge_active() if they have been
3962 * isolated for migration.
3965 set_page_huge_active(page
);
3975 restore_reserve_on_error(h
, vma
, haddr
, page
);
3981 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
3983 unsigned long key
[2];
3986 key
[0] = (unsigned long) mapping
;
3989 hash
= jhash2((u32
*)&key
, sizeof(key
)/(sizeof(u32
)), 0);
3991 return hash
& (num_fault_mutexes
- 1);
3995 * For uniprocesor systems we always use a single mutex, so just
3996 * return 0 and avoid the hashing overhead.
3998 u32
hugetlb_fault_mutex_hash(struct address_space
*mapping
, pgoff_t idx
)
4004 vm_fault_t
hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4005 unsigned long address
, unsigned int flags
)
4012 struct page
*page
= NULL
;
4013 struct page
*pagecache_page
= NULL
;
4014 struct hstate
*h
= hstate_vma(vma
);
4015 struct address_space
*mapping
;
4016 int need_wait_lock
= 0;
4017 unsigned long haddr
= address
& huge_page_mask(h
);
4019 ptep
= huge_pte_offset(mm
, haddr
, huge_page_size(h
));
4021 entry
= huge_ptep_get(ptep
);
4022 if (unlikely(is_hugetlb_entry_migration(entry
))) {
4023 migration_entry_wait_huge(vma
, mm
, ptep
);
4025 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry
)))
4026 return VM_FAULT_HWPOISON_LARGE
|
4027 VM_FAULT_SET_HINDEX(hstate_index(h
));
4029 ptep
= huge_pte_alloc(mm
, haddr
, huge_page_size(h
));
4031 return VM_FAULT_OOM
;
4034 mapping
= vma
->vm_file
->f_mapping
;
4035 idx
= vma_hugecache_offset(h
, vma
, haddr
);
4038 * Serialize hugepage allocation and instantiation, so that we don't
4039 * get spurious allocation failures if two CPUs race to instantiate
4040 * the same page in the page cache.
4042 hash
= hugetlb_fault_mutex_hash(mapping
, idx
);
4043 mutex_lock(&hugetlb_fault_mutex_table
[hash
]);
4045 entry
= huge_ptep_get(ptep
);
4046 if (huge_pte_none(entry
)) {
4047 ret
= hugetlb_no_page(mm
, vma
, mapping
, idx
, address
, ptep
, flags
);
4054 * entry could be a migration/hwpoison entry at this point, so this
4055 * check prevents the kernel from going below assuming that we have
4056 * a active hugepage in pagecache. This goto expects the 2nd page fault,
4057 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
4060 if (!pte_present(entry
))
4064 * If we are going to COW the mapping later, we examine the pending
4065 * reservations for this page now. This will ensure that any
4066 * allocations necessary to record that reservation occur outside the
4067 * spinlock. For private mappings, we also lookup the pagecache
4068 * page now as it is used to determine if a reservation has been
4071 if ((flags
& FAULT_FLAG_WRITE
) && !huge_pte_write(entry
)) {
4072 if (vma_needs_reservation(h
, vma
, haddr
) < 0) {
4076 /* Just decrements count, does not deallocate */
4077 vma_end_reservation(h
, vma
, haddr
);
4079 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4080 pagecache_page
= hugetlbfs_pagecache_page(h
,
4084 ptl
= huge_pte_lock(h
, mm
, ptep
);
4086 /* Check for a racing update before calling hugetlb_cow */
4087 if (unlikely(!pte_same(entry
, huge_ptep_get(ptep
))))
4091 * hugetlb_cow() requires page locks of pte_page(entry) and
4092 * pagecache_page, so here we need take the former one
4093 * when page != pagecache_page or !pagecache_page.
4095 page
= pte_page(entry
);
4096 if (page
!= pagecache_page
)
4097 if (!trylock_page(page
)) {
4104 if (flags
& FAULT_FLAG_WRITE
) {
4105 if (!huge_pte_write(entry
)) {
4106 ret
= hugetlb_cow(mm
, vma
, address
, ptep
,
4107 pagecache_page
, ptl
);
4110 entry
= huge_pte_mkdirty(entry
);
4112 entry
= pte_mkyoung(entry
);
4113 if (huge_ptep_set_access_flags(vma
, haddr
, ptep
, entry
,
4114 flags
& FAULT_FLAG_WRITE
))
4115 update_mmu_cache(vma
, haddr
, ptep
);
4117 if (page
!= pagecache_page
)
4123 if (pagecache_page
) {
4124 unlock_page(pagecache_page
);
4125 put_page(pagecache_page
);
4128 mutex_unlock(&hugetlb_fault_mutex_table
[hash
]);
4130 * Generally it's safe to hold refcount during waiting page lock. But
4131 * here we just wait to defer the next page fault to avoid busy loop and
4132 * the page is not used after unlocked before returning from the current
4133 * page fault. So we are safe from accessing freed page, even if we wait
4134 * here without taking refcount.
4137 wait_on_page_locked(page
);
4142 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4143 * modifications for huge pages.
4145 int hugetlb_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
4147 struct vm_area_struct
*dst_vma
,
4148 unsigned long dst_addr
,
4149 unsigned long src_addr
,
4150 struct page
**pagep
)
4152 struct address_space
*mapping
;
4155 int vm_shared
= dst_vma
->vm_flags
& VM_SHARED
;
4156 struct hstate
*h
= hstate_vma(dst_vma
);
4164 page
= alloc_huge_page(dst_vma
, dst_addr
, 0);
4168 ret
= copy_huge_page_from_user(page
,
4169 (const void __user
*) src_addr
,
4170 pages_per_huge_page(h
), false);
4172 /* fallback to copy_from_user outside mmap_sem */
4173 if (unlikely(ret
)) {
4176 /* don't free the page */
4185 * The memory barrier inside __SetPageUptodate makes sure that
4186 * preceding stores to the page contents become visible before
4187 * the set_pte_at() write.
4189 __SetPageUptodate(page
);
4191 mapping
= dst_vma
->vm_file
->f_mapping
;
4192 idx
= vma_hugecache_offset(h
, dst_vma
, dst_addr
);
4195 * If shared, add to page cache
4198 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4201 goto out_release_nounlock
;
4204 * Serialization between remove_inode_hugepages() and
4205 * huge_add_to_page_cache() below happens through the
4206 * hugetlb_fault_mutex_table that here must be hold by
4209 ret
= huge_add_to_page_cache(page
, mapping
, idx
);
4211 goto out_release_nounlock
;
4214 ptl
= huge_pte_lockptr(h
, dst_mm
, dst_pte
);
4218 * Recheck the i_size after holding PT lock to make sure not
4219 * to leave any page mapped (as page_mapped()) beyond the end
4220 * of the i_size (remove_inode_hugepages() is strict about
4221 * enforcing that). If we bail out here, we'll also leave a
4222 * page in the radix tree in the vm_shared case beyond the end
4223 * of the i_size, but remove_inode_hugepages() will take care
4224 * of it as soon as we drop the hugetlb_fault_mutex_table.
4226 size
= i_size_read(mapping
->host
) >> huge_page_shift(h
);
4229 goto out_release_unlock
;
4232 if (!huge_pte_none(huge_ptep_get(dst_pte
)))
4233 goto out_release_unlock
;
4236 page_dup_rmap(page
, true);
4238 ClearPagePrivate(page
);
4239 hugepage_add_new_anon_rmap(page
, dst_vma
, dst_addr
);
4242 _dst_pte
= make_huge_pte(dst_vma
, page
, dst_vma
->vm_flags
& VM_WRITE
);
4243 if (dst_vma
->vm_flags
& VM_WRITE
)
4244 _dst_pte
= huge_pte_mkdirty(_dst_pte
);
4245 _dst_pte
= pte_mkyoung(_dst_pte
);
4247 set_huge_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
4249 (void)huge_ptep_set_access_flags(dst_vma
, dst_addr
, dst_pte
, _dst_pte
,
4250 dst_vma
->vm_flags
& VM_WRITE
);
4251 hugetlb_count_add(pages_per_huge_page(h
), dst_mm
);
4253 /* No need to invalidate - it was non-present before */
4254 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
4257 set_page_huge_active(page
);
4267 out_release_nounlock
:
4272 long follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
4273 struct page
**pages
, struct vm_area_struct
**vmas
,
4274 unsigned long *position
, unsigned long *nr_pages
,
4275 long i
, unsigned int flags
, int *locked
)
4277 unsigned long pfn_offset
;
4278 unsigned long vaddr
= *position
;
4279 unsigned long remainder
= *nr_pages
;
4280 struct hstate
*h
= hstate_vma(vma
);
4283 while (vaddr
< vma
->vm_end
&& remainder
) {
4285 spinlock_t
*ptl
= NULL
;
4290 * If we have a pending SIGKILL, don't keep faulting pages and
4291 * potentially allocating memory.
4293 if (fatal_signal_pending(current
)) {
4299 * Some archs (sparc64, sh*) have multiple pte_ts to
4300 * each hugepage. We have to make sure we get the
4301 * first, for the page indexing below to work.
4303 * Note that page table lock is not held when pte is null.
4305 pte
= huge_pte_offset(mm
, vaddr
& huge_page_mask(h
),
4308 ptl
= huge_pte_lock(h
, mm
, pte
);
4309 absent
= !pte
|| huge_pte_none(huge_ptep_get(pte
));
4312 * When coredumping, it suits get_dump_page if we just return
4313 * an error where there's an empty slot with no huge pagecache
4314 * to back it. This way, we avoid allocating a hugepage, and
4315 * the sparse dumpfile avoids allocating disk blocks, but its
4316 * huge holes still show up with zeroes where they need to be.
4318 if (absent
&& (flags
& FOLL_DUMP
) &&
4319 !hugetlbfs_pagecache_present(h
, vma
, vaddr
)) {
4327 * We need call hugetlb_fault for both hugepages under migration
4328 * (in which case hugetlb_fault waits for the migration,) and
4329 * hwpoisoned hugepages (in which case we need to prevent the
4330 * caller from accessing to them.) In order to do this, we use
4331 * here is_swap_pte instead of is_hugetlb_entry_migration and
4332 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4333 * both cases, and because we can't follow correct pages
4334 * directly from any kind of swap entries.
4336 if (absent
|| is_swap_pte(huge_ptep_get(pte
)) ||
4337 ((flags
& FOLL_WRITE
) &&
4338 !huge_pte_write(huge_ptep_get(pte
)))) {
4340 unsigned int fault_flags
= 0;
4344 if (flags
& FOLL_WRITE
)
4345 fault_flags
|= FAULT_FLAG_WRITE
;
4347 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
4348 if (flags
& FOLL_NOWAIT
)
4349 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
|
4350 FAULT_FLAG_RETRY_NOWAIT
;
4351 if (flags
& FOLL_TRIED
) {
4352 VM_WARN_ON_ONCE(fault_flags
&
4353 FAULT_FLAG_ALLOW_RETRY
);
4354 fault_flags
|= FAULT_FLAG_TRIED
;
4356 ret
= hugetlb_fault(mm
, vma
, vaddr
, fault_flags
);
4357 if (ret
& VM_FAULT_ERROR
) {
4358 err
= vm_fault_to_errno(ret
, flags
);
4362 if (ret
& VM_FAULT_RETRY
) {
4364 !(fault_flags
& FAULT_FLAG_RETRY_NOWAIT
))
4368 * VM_FAULT_RETRY must not return an
4369 * error, it will return zero
4372 * No need to update "position" as the
4373 * caller will not check it after
4374 * *nr_pages is set to 0.
4381 pfn_offset
= (vaddr
& ~huge_page_mask(h
)) >> PAGE_SHIFT
;
4382 page
= pte_page(huge_ptep_get(pte
));
4385 * If subpage information not requested, update counters
4386 * and skip the same_page loop below.
4388 if (!pages
&& !vmas
&& !pfn_offset
&&
4389 (vaddr
+ huge_page_size(h
) < vma
->vm_end
) &&
4390 (remainder
>= pages_per_huge_page(h
))) {
4391 vaddr
+= huge_page_size(h
);
4392 remainder
-= pages_per_huge_page(h
);
4393 i
+= pages_per_huge_page(h
);
4400 pages
[i
] = mem_map_offset(page
, pfn_offset
);
4402 * try_grab_page() should always succeed here, because:
4403 * a) we hold the ptl lock, and b) we've just checked
4404 * that the huge page is present in the page tables. If
4405 * the huge page is present, then the tail pages must
4406 * also be present. The ptl prevents the head page and
4407 * tail pages from being rearranged in any way. So this
4408 * page must be available at this point, unless the page
4409 * refcount overflowed:
4411 if (WARN_ON_ONCE(!try_grab_page(pages
[i
], flags
))) {
4426 if (vaddr
< vma
->vm_end
&& remainder
&&
4427 pfn_offset
< pages_per_huge_page(h
)) {
4429 * We use pfn_offset to avoid touching the pageframes
4430 * of this compound page.
4436 *nr_pages
= remainder
;
4438 * setting position is actually required only if remainder is
4439 * not zero but it's faster not to add a "if (remainder)"
4447 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4449 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4452 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4455 unsigned long hugetlb_change_protection(struct vm_area_struct
*vma
,
4456 unsigned long address
, unsigned long end
, pgprot_t newprot
)
4458 struct mm_struct
*mm
= vma
->vm_mm
;
4459 unsigned long start
= address
;
4462 struct hstate
*h
= hstate_vma(vma
);
4463 unsigned long pages
= 0;
4464 bool shared_pmd
= false;
4465 struct mmu_notifier_range range
;
4468 * In the case of shared PMDs, the area to flush could be beyond
4469 * start/end. Set range.start/range.end to cover the maximum possible
4470 * range if PMD sharing is possible.
4472 mmu_notifier_range_init(&range
, MMU_NOTIFY_PROTECTION_VMA
,
4473 0, vma
, mm
, start
, end
);
4474 adjust_range_if_pmd_sharing_possible(vma
, &range
.start
, &range
.end
);
4476 BUG_ON(address
>= end
);
4477 flush_cache_range(vma
, range
.start
, range
.end
);
4479 mmu_notifier_invalidate_range_start(&range
);
4480 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
4481 for (; address
< end
; address
+= huge_page_size(h
)) {
4483 ptep
= huge_pte_offset(mm
, address
, huge_page_size(h
));
4486 ptl
= huge_pte_lock(h
, mm
, ptep
);
4487 if (huge_pmd_unshare(mm
, &address
, ptep
)) {
4493 pte
= huge_ptep_get(ptep
);
4494 if (unlikely(is_hugetlb_entry_hwpoisoned(pte
))) {
4498 if (unlikely(is_hugetlb_entry_migration(pte
))) {
4499 swp_entry_t entry
= pte_to_swp_entry(pte
);
4501 if (is_write_migration_entry(entry
)) {
4504 make_migration_entry_read(&entry
);
4505 newpte
= swp_entry_to_pte(entry
);
4506 set_huge_swap_pte_at(mm
, address
, ptep
,
4507 newpte
, huge_page_size(h
));
4513 if (!huge_pte_none(pte
)) {
4516 old_pte
= huge_ptep_modify_prot_start(vma
, address
, ptep
);
4517 pte
= pte_mkhuge(huge_pte_modify(old_pte
, newprot
));
4518 pte
= arch_make_huge_pte(pte
, vma
, NULL
, 0);
4519 huge_ptep_modify_prot_commit(vma
, address
, ptep
, old_pte
, pte
);
4525 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4526 * may have cleared our pud entry and done put_page on the page table:
4527 * once we release i_mmap_rwsem, another task can do the final put_page
4528 * and that page table be reused and filled with junk. If we actually
4529 * did unshare a page of pmds, flush the range corresponding to the pud.
4532 flush_hugetlb_tlb_range(vma
, range
.start
, range
.end
);
4534 flush_hugetlb_tlb_range(vma
, start
, end
);
4536 * No need to call mmu_notifier_invalidate_range() we are downgrading
4537 * page table protection not changing it to point to a new page.
4539 * See Documentation/vm/mmu_notifier.rst
4541 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
4542 mmu_notifier_invalidate_range_end(&range
);
4544 return pages
<< h
->order
;
4547 int hugetlb_reserve_pages(struct inode
*inode
,
4549 struct vm_area_struct
*vma
,
4550 vm_flags_t vm_flags
)
4553 struct hstate
*h
= hstate_inode(inode
);
4554 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4555 struct resv_map
*resv_map
;
4558 /* This should never happen */
4560 VM_WARN(1, "%s called with a negative range\n", __func__
);
4565 * Only apply hugepage reservation if asked. At fault time, an
4566 * attempt will be made for VM_NORESERVE to allocate a page
4567 * without using reserves
4569 if (vm_flags
& VM_NORESERVE
)
4573 * Shared mappings base their reservation on the number of pages that
4574 * are already allocated on behalf of the file. Private mappings need
4575 * to reserve the full area even if read-only as mprotect() may be
4576 * called to make the mapping read-write. Assume !vma is a shm mapping
4578 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4580 * resv_map can not be NULL as hugetlb_reserve_pages is only
4581 * called for inodes for which resv_maps were created (see
4582 * hugetlbfs_get_inode).
4584 resv_map
= inode_resv_map(inode
);
4586 chg
= region_chg(resv_map
, from
, to
);
4589 resv_map
= resv_map_alloc();
4595 set_vma_resv_map(vma
, resv_map
);
4596 set_vma_resv_flags(vma
, HPAGE_RESV_OWNER
);
4605 * There must be enough pages in the subpool for the mapping. If
4606 * the subpool has a minimum size, there may be some global
4607 * reservations already in place (gbl_reserve).
4609 gbl_reserve
= hugepage_subpool_get_pages(spool
, chg
);
4610 if (gbl_reserve
< 0) {
4616 * Check enough hugepages are available for the reservation.
4617 * Hand the pages back to the subpool if there are not
4619 ret
= hugetlb_acct_memory(h
, gbl_reserve
);
4621 /* put back original number of pages, chg */
4622 (void)hugepage_subpool_put_pages(spool
, chg
);
4627 * Account for the reservations made. Shared mappings record regions
4628 * that have reservations as they are shared by multiple VMAs.
4629 * When the last VMA disappears, the region map says how much
4630 * the reservation was and the page cache tells how much of
4631 * the reservation was consumed. Private mappings are per-VMA and
4632 * only the consumed reservations are tracked. When the VMA
4633 * disappears, the original reservation is the VMA size and the
4634 * consumed reservations are stored in the map. Hence, nothing
4635 * else has to be done for private mappings here
4637 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
) {
4638 long add
= region_add(resv_map
, from
, to
);
4640 if (unlikely(chg
> add
)) {
4642 * pages in this range were added to the reserve
4643 * map between region_chg and region_add. This
4644 * indicates a race with alloc_huge_page. Adjust
4645 * the subpool and reserve counts modified above
4646 * based on the difference.
4650 rsv_adjust
= hugepage_subpool_put_pages(spool
,
4652 hugetlb_acct_memory(h
, -rsv_adjust
);
4657 if (!vma
|| vma
->vm_flags
& VM_MAYSHARE
)
4658 /* Don't call region_abort if region_chg failed */
4660 region_abort(resv_map
, from
, to
);
4661 if (vma
&& is_vma_resv_set(vma
, HPAGE_RESV_OWNER
))
4662 kref_put(&resv_map
->refs
, resv_map_release
);
4666 long hugetlb_unreserve_pages(struct inode
*inode
, long start
, long end
,
4669 struct hstate
*h
= hstate_inode(inode
);
4670 struct resv_map
*resv_map
= inode_resv_map(inode
);
4672 struct hugepage_subpool
*spool
= subpool_inode(inode
);
4676 * Since this routine can be called in the evict inode path for all
4677 * hugetlbfs inodes, resv_map could be NULL.
4680 chg
= region_del(resv_map
, start
, end
);
4682 * region_del() can fail in the rare case where a region
4683 * must be split and another region descriptor can not be
4684 * allocated. If end == LONG_MAX, it will not fail.
4690 spin_lock(&inode
->i_lock
);
4691 inode
->i_blocks
-= (blocks_per_huge_page(h
) * freed
);
4692 spin_unlock(&inode
->i_lock
);
4695 * If the subpool has a minimum size, the number of global
4696 * reservations to be released may be adjusted.
4698 gbl_reserve
= hugepage_subpool_put_pages(spool
, (chg
- freed
));
4699 hugetlb_acct_memory(h
, -gbl_reserve
);
4704 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4705 static unsigned long page_table_shareable(struct vm_area_struct
*svma
,
4706 struct vm_area_struct
*vma
,
4707 unsigned long addr
, pgoff_t idx
)
4709 unsigned long saddr
= ((idx
- svma
->vm_pgoff
) << PAGE_SHIFT
) +
4711 unsigned long sbase
= saddr
& PUD_MASK
;
4712 unsigned long s_end
= sbase
+ PUD_SIZE
;
4714 /* Allow segments to share if only one is marked locked */
4715 unsigned long vm_flags
= vma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4716 unsigned long svm_flags
= svma
->vm_flags
& VM_LOCKED_CLEAR_MASK
;
4719 * match the virtual addresses, permission and the alignment of the
4722 if (pmd_index(addr
) != pmd_index(saddr
) ||
4723 vm_flags
!= svm_flags
||
4724 sbase
< svma
->vm_start
|| svma
->vm_end
< s_end
)
4730 static bool vma_shareable(struct vm_area_struct
*vma
, unsigned long addr
)
4732 unsigned long base
= addr
& PUD_MASK
;
4733 unsigned long end
= base
+ PUD_SIZE
;
4736 * check on proper vm_flags and page table alignment
4738 if (vma
->vm_flags
& VM_MAYSHARE
&& range_in_vma(vma
, base
, end
))
4744 * Determine if start,end range within vma could be mapped by shared pmd.
4745 * If yes, adjust start and end to cover range associated with possible
4746 * shared pmd mappings.
4748 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
4749 unsigned long *start
, unsigned long *end
)
4751 unsigned long check_addr
= *start
;
4753 if (!(vma
->vm_flags
& VM_MAYSHARE
))
4756 for (check_addr
= *start
; check_addr
< *end
; check_addr
+= PUD_SIZE
) {
4757 unsigned long a_start
= check_addr
& PUD_MASK
;
4758 unsigned long a_end
= a_start
+ PUD_SIZE
;
4761 * If sharing is possible, adjust start/end if necessary.
4763 if (range_in_vma(vma
, a_start
, a_end
)) {
4764 if (a_start
< *start
)
4773 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4774 * and returns the corresponding pte. While this is not necessary for the
4775 * !shared pmd case because we can allocate the pmd later as well, it makes the
4776 * code much cleaner. pmd allocation is essential for the shared case because
4777 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4778 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4779 * bad pmd for sharing.
4781 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4783 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
4784 struct address_space
*mapping
= vma
->vm_file
->f_mapping
;
4785 pgoff_t idx
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) +
4787 struct vm_area_struct
*svma
;
4788 unsigned long saddr
;
4793 if (!vma_shareable(vma
, addr
))
4794 return (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4796 i_mmap_lock_read(mapping
);
4797 vma_interval_tree_foreach(svma
, &mapping
->i_mmap
, idx
, idx
) {
4801 saddr
= page_table_shareable(svma
, vma
, addr
, idx
);
4803 spte
= huge_pte_offset(svma
->vm_mm
, saddr
,
4804 vma_mmu_pagesize(svma
));
4806 get_page(virt_to_page(spte
));
4815 ptl
= huge_pte_lock(hstate_vma(vma
), mm
, spte
);
4816 if (pud_none(*pud
)) {
4817 pud_populate(mm
, pud
,
4818 (pmd_t
*)((unsigned long)spte
& PAGE_MASK
));
4821 put_page(virt_to_page(spte
));
4825 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4826 i_mmap_unlock_read(mapping
);
4831 * unmap huge page backed by shared pte.
4833 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4834 * indicated by page_count > 1, unmap is achieved by clearing pud and
4835 * decrementing the ref count. If count == 1, the pte page is not shared.
4837 * called with page table lock held.
4839 * returns: 1 successfully unmapped a shared pte page
4840 * 0 the underlying pte page is not shared, or it is the last user
4842 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4844 pgd_t
*pgd
= pgd_offset(mm
, *addr
);
4845 p4d_t
*p4d
= p4d_offset(pgd
, *addr
);
4846 pud_t
*pud
= pud_offset(p4d
, *addr
);
4848 BUG_ON(page_count(virt_to_page(ptep
)) == 0);
4849 if (page_count(virt_to_page(ptep
)) == 1)
4853 put_page(virt_to_page(ptep
));
4855 *addr
= ALIGN(*addr
, HPAGE_SIZE
* PTRS_PER_PTE
) - HPAGE_SIZE
;
4858 #define want_pmd_share() (1)
4859 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4860 pte_t
*huge_pmd_share(struct mm_struct
*mm
, unsigned long addr
, pud_t
*pud
)
4865 int huge_pmd_unshare(struct mm_struct
*mm
, unsigned long *addr
, pte_t
*ptep
)
4870 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct
*vma
,
4871 unsigned long *start
, unsigned long *end
)
4874 #define want_pmd_share() (0)
4875 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4877 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4878 pte_t
*huge_pte_alloc(struct mm_struct
*mm
,
4879 unsigned long addr
, unsigned long sz
)
4886 pgd
= pgd_offset(mm
, addr
);
4887 p4d
= p4d_alloc(mm
, pgd
, addr
);
4890 pud
= pud_alloc(mm
, p4d
, addr
);
4892 if (sz
== PUD_SIZE
) {
4895 BUG_ON(sz
!= PMD_SIZE
);
4896 if (want_pmd_share() && pud_none(*pud
))
4897 pte
= huge_pmd_share(mm
, addr
, pud
);
4899 pte
= (pte_t
*)pmd_alloc(mm
, pud
, addr
);
4902 BUG_ON(pte
&& pte_present(*pte
) && !pte_huge(*pte
));
4908 * huge_pte_offset() - Walk the page table to resolve the hugepage
4909 * entry at address @addr
4911 * Return: Pointer to page table or swap entry (PUD or PMD) for
4912 * address @addr, or NULL if a p*d_none() entry is encountered and the
4913 * size @sz doesn't match the hugepage size at this level of the page
4916 pte_t
*huge_pte_offset(struct mm_struct
*mm
,
4917 unsigned long addr
, unsigned long sz
)
4924 pgd
= pgd_offset(mm
, addr
);
4925 if (!pgd_present(*pgd
))
4927 p4d
= p4d_offset(pgd
, addr
);
4928 if (!p4d_present(*p4d
))
4931 pud
= pud_offset(p4d
, addr
);
4932 if (sz
!= PUD_SIZE
&& pud_none(*pud
))
4934 /* hugepage or swap? */
4935 if (pud_huge(*pud
) || !pud_present(*pud
))
4936 return (pte_t
*)pud
;
4938 pmd
= pmd_offset(pud
, addr
);
4939 if (sz
!= PMD_SIZE
&& pmd_none(*pmd
))
4941 /* hugepage or swap? */
4942 if (pmd_huge(*pmd
) || !pmd_present(*pmd
))
4943 return (pte_t
*)pmd
;
4948 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4951 * These functions are overwritable if your architecture needs its own
4954 struct page
* __weak
4955 follow_huge_addr(struct mm_struct
*mm
, unsigned long address
,
4958 return ERR_PTR(-EINVAL
);
4961 struct page
* __weak
4962 follow_huge_pd(struct vm_area_struct
*vma
,
4963 unsigned long address
, hugepd_t hpd
, int flags
, int pdshift
)
4965 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
4969 struct page
* __weak
4970 follow_huge_pmd(struct mm_struct
*mm
, unsigned long address
,
4971 pmd_t
*pmd
, int flags
)
4973 struct page
*page
= NULL
;
4977 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
4978 if (WARN_ON_ONCE((flags
& (FOLL_PIN
| FOLL_GET
)) ==
4979 (FOLL_PIN
| FOLL_GET
)))
4983 ptl
= pmd_lockptr(mm
, pmd
);
4986 * make sure that the address range covered by this pmd is not
4987 * unmapped from other threads.
4989 if (!pmd_huge(*pmd
))
4991 pte
= huge_ptep_get((pte_t
*)pmd
);
4992 if (pte_present(pte
)) {
4993 page
= pmd_page(*pmd
) + ((address
& ~PMD_MASK
) >> PAGE_SHIFT
);
4995 * try_grab_page() should always succeed here, because: a) we
4996 * hold the pmd (ptl) lock, and b) we've just checked that the
4997 * huge pmd (head) page is present in the page tables. The ptl
4998 * prevents the head page and tail pages from being rearranged
4999 * in any way. So this page must be available at this point,
5000 * unless the page refcount overflowed:
5002 if (WARN_ON_ONCE(!try_grab_page(page
, flags
))) {
5007 if (is_hugetlb_entry_migration(pte
)) {
5009 __migration_entry_wait(mm
, (pte_t
*)pmd
, ptl
);
5013 * hwpoisoned entry is treated as no_page_table in
5014 * follow_page_mask().
5022 struct page
* __weak
5023 follow_huge_pud(struct mm_struct
*mm
, unsigned long address
,
5024 pud_t
*pud
, int flags
)
5026 if (flags
& (FOLL_GET
| FOLL_PIN
))
5029 return pte_page(*(pte_t
*)pud
) + ((address
& ~PUD_MASK
) >> PAGE_SHIFT
);
5032 struct page
* __weak
5033 follow_huge_pgd(struct mm_struct
*mm
, unsigned long address
, pgd_t
*pgd
, int flags
)
5035 if (flags
& (FOLL_GET
| FOLL_PIN
))
5038 return pte_page(*(pte_t
*)pgd
) + ((address
& ~PGDIR_MASK
) >> PAGE_SHIFT
);
5041 bool isolate_huge_page(struct page
*page
, struct list_head
*list
)
5045 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5046 spin_lock(&hugetlb_lock
);
5047 if (!page_huge_active(page
) || !get_page_unless_zero(page
)) {
5051 clear_page_huge_active(page
);
5052 list_move_tail(&page
->lru
, list
);
5054 spin_unlock(&hugetlb_lock
);
5058 void putback_active_hugepage(struct page
*page
)
5060 VM_BUG_ON_PAGE(!PageHead(page
), page
);
5061 spin_lock(&hugetlb_lock
);
5062 set_page_huge_active(page
);
5063 list_move_tail(&page
->lru
, &(page_hstate(page
))->hugepage_activelist
);
5064 spin_unlock(&hugetlb_lock
);
5068 void move_hugetlb_state(struct page
*oldpage
, struct page
*newpage
, int reason
)
5070 struct hstate
*h
= page_hstate(oldpage
);
5072 hugetlb_cgroup_migrate(oldpage
, newpage
);
5073 set_page_owner_migrate_reason(newpage
, reason
);
5076 * transfer temporary state of the new huge page. This is
5077 * reverse to other transitions because the newpage is going to
5078 * be final while the old one will be freed so it takes over
5079 * the temporary status.
5081 * Also note that we have to transfer the per-node surplus state
5082 * here as well otherwise the global surplus count will not match
5085 if (PageHugeTemporary(newpage
)) {
5086 int old_nid
= page_to_nid(oldpage
);
5087 int new_nid
= page_to_nid(newpage
);
5089 SetPageHugeTemporary(oldpage
);
5090 ClearPageHugeTemporary(newpage
);
5092 spin_lock(&hugetlb_lock
);
5093 if (h
->surplus_huge_pages_node
[old_nid
]) {
5094 h
->surplus_huge_pages_node
[old_nid
]--;
5095 h
->surplus_huge_pages_node
[new_nid
]++;
5097 spin_unlock(&hugetlb_lock
);