2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/module.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/bootmem.h>
20 #include <linux/sysfs.h>
21 #include <linux/slab.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/page-isolation.h>
26 #include <linux/jhash.h>
29 #include <asm/pgtable.h>
33 #include <linux/hugetlb.h>
34 #include <linux/hugetlb_cgroup.h>
35 #include <linux/node.h>
38 int hugepages_treat_as_movable;
40 int hugetlb_max_hstate __read_mostly;
41 unsigned int default_hstate_idx;
42 struct hstate hstates[HUGE_MAX_HSTATE];
44 * Minimum page order among possible hugepage sizes, set to a proper value
47 static unsigned int minimum_order __read_mostly = UINT_MAX;
49 __initdata LIST_HEAD(huge_boot_pages);
51 /* for command line parsing */
52 static struct hstate * __initdata parsed_hstate;
53 static unsigned long __initdata default_hstate_max_huge_pages;
54 static unsigned long __initdata default_hstate_size;
57 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
58 * free_huge_pages, and surplus_huge_pages.
60 DEFINE_SPINLOCK(hugetlb_lock);
63 * Serializes faults on the same logical page. This is used to
64 * prevent spurious OOMs when the hugepage pool is fully utilized.
66 static int num_fault_mutexes;
67 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
69 /* Forward declaration */
70 static int hugetlb_acct_memory(struct hstate *h, long delta);
72 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
74 bool free = (spool->count == 0) && (spool->used_hpages == 0);
76 spin_unlock(&spool->lock);
78 /* If no pages are used, and no other handles to the subpool
79 * remain, give up any reservations mased on minimum size and
82 if (spool->min_hpages != -1)
83 hugetlb_acct_memory(spool->hstate,
89 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
92 struct hugepage_subpool *spool;
94 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
98 spin_lock_init(&spool->lock);
100 spool->max_hpages = max_hpages;
102 spool->min_hpages = min_hpages;
104 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
108 spool->rsv_hpages = min_hpages;
113 void hugepage_put_subpool(struct hugepage_subpool *spool)
115 spin_lock(&spool->lock);
116 BUG_ON(!spool->count);
118 unlock_or_release_subpool(spool);
122 * Subpool accounting for allocating and reserving pages.
123 * Return -ENOMEM if there are not enough resources to satisfy the
124 * the request. Otherwise, return the number of pages by which the
125 * global pools must be adjusted (upward). The returned value may
126 * only be different than the passed value (delta) in the case where
127 * a subpool minimum size must be manitained.
129 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
137 spin_lock(&spool->lock);
139 if (spool->max_hpages != -1) { /* maximum size accounting */
140 if ((spool->used_hpages + delta) <= spool->max_hpages)
141 spool->used_hpages += delta;
148 if (spool->min_hpages != -1) { /* minimum size accounting */
149 if (delta > spool->rsv_hpages) {
151 * Asking for more reserves than those already taken on
152 * behalf of subpool. Return difference.
154 ret = delta - spool->rsv_hpages;
155 spool->rsv_hpages = 0;
157 ret = 0; /* reserves already accounted for */
158 spool->rsv_hpages -= delta;
163 spin_unlock(&spool->lock);
168 * Subpool accounting for freeing and unreserving pages.
169 * Return the number of global page reservations that must be dropped.
170 * The return value may only be different than the passed value (delta)
171 * in the case where a subpool minimum size must be maintained.
173 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
181 spin_lock(&spool->lock);
183 if (spool->max_hpages != -1) /* maximum size accounting */
184 spool->used_hpages -= delta;
186 if (spool->min_hpages != -1) { /* minimum size accounting */
187 if (spool->rsv_hpages + delta <= spool->min_hpages)
190 ret = spool->rsv_hpages + delta - spool->min_hpages;
192 spool->rsv_hpages += delta;
193 if (spool->rsv_hpages > spool->min_hpages)
194 spool->rsv_hpages = spool->min_hpages;
198 * If hugetlbfs_put_super couldn't free spool due to an outstanding
199 * quota reference, free it now.
201 unlock_or_release_subpool(spool);
206 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
208 return HUGETLBFS_SB(inode->i_sb)->spool;
211 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
213 return subpool_inode(file_inode(vma->vm_file));
217 * Region tracking -- allows tracking of reservations and instantiated pages
218 * across the pages in a mapping.
220 * The region data structures are embedded into a resv_map and protected
221 * by a resv_map's lock. The set of regions within the resv_map represent
222 * reservations for huge pages, or huge pages that have already been
223 * instantiated within the map. The from and to elements are huge page
224 * indicies into the associated mapping. from indicates the starting index
225 * of the region. to represents the first index past the end of the region.
227 * For example, a file region structure with from == 0 and to == 4 represents
228 * four huge pages in a mapping. It is important to note that the to element
229 * represents the first element past the end of the region. This is used in
230 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
232 * Interval notation of the form [from, to) will be used to indicate that
233 * the endpoint from is inclusive and to is exclusive.
236 struct list_head link;
242 * Add the huge page range represented by [f, t) to the reserve
243 * map. In the normal case, existing regions will be expanded
244 * to accommodate the specified range. Sufficient regions should
245 * exist for expansion due to the previous call to region_chg
246 * with the same range. However, it is possible that region_del
247 * could have been called after region_chg and modifed the map
248 * in such a way that no region exists to be expanded. In this
249 * case, pull a region descriptor from the cache associated with
250 * the map and use that for the new range.
252 * Return the number of new huge pages added to the map. This
253 * number is greater than or equal to zero.
255 static long region_add(struct resv_map *resv, long f, long t)
257 struct list_head *head = &resv->regions;
258 struct file_region *rg, *nrg, *trg;
261 spin_lock(&resv->lock);
262 /* Locate the region we are either in or before. */
263 list_for_each_entry(rg, head, link)
268 * If no region exists which can be expanded to include the
269 * specified range, the list must have been modified by an
270 * interleving call to region_del(). Pull a region descriptor
271 * from the cache and use it for this range.
273 if (&rg->link == head || t < rg->from) {
274 VM_BUG_ON(resv->region_cache_count <= 0);
276 resv->region_cache_count--;
277 nrg = list_first_entry(&resv->region_cache, struct file_region,
279 list_del(&nrg->link);
283 list_add(&nrg->link, rg->link.prev);
289 /* Round our left edge to the current segment if it encloses us. */
293 /* Check for and consume any regions we now overlap with. */
295 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
296 if (&rg->link == head)
301 /* If this area reaches higher then extend our area to
302 * include it completely. If this is not the first area
303 * which we intend to reuse, free it. */
307 /* Decrement return value by the deleted range.
308 * Another range will span this area so that by
309 * end of routine add will be >= zero
311 add -= (rg->to - rg->from);
317 add += (nrg->from - f); /* Added to beginning of region */
319 add += t - nrg->to; /* Added to end of region */
323 resv->adds_in_progress--;
324 spin_unlock(&resv->lock);
330 * Examine the existing reserve map and determine how many
331 * huge pages in the specified range [f, t) are NOT currently
332 * represented. This routine is called before a subsequent
333 * call to region_add that will actually modify the reserve
334 * map to add the specified range [f, t). region_chg does
335 * not change the number of huge pages represented by the
336 * map. However, if the existing regions in the map can not
337 * be expanded to represent the new range, a new file_region
338 * structure is added to the map as a placeholder. This is
339 * so that the subsequent region_add call will have all the
340 * regions it needs and will not fail.
342 * Upon entry, region_chg will also examine the cache of region descriptors
343 * associated with the map. If there are not enough descriptors cached, one
344 * will be allocated for the in progress add operation.
346 * Returns the number of huge pages that need to be added to the existing
347 * reservation map for the range [f, t). This number is greater or equal to
348 * zero. -ENOMEM is returned if a new file_region structure or cache entry
349 * is needed and can not be allocated.
351 static long region_chg(struct resv_map *resv, long f, long t)
353 struct list_head *head = &resv->regions;
354 struct file_region *rg, *nrg = NULL;
358 spin_lock(&resv->lock);
360 resv->adds_in_progress++;
363 * Check for sufficient descriptors in the cache to accommodate
364 * the number of in progress add operations.
366 if (resv->adds_in_progress > resv->region_cache_count) {
367 struct file_region *trg;
369 VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1);
370 /* Must drop lock to allocate a new descriptor. */
371 resv->adds_in_progress--;
372 spin_unlock(&resv->lock);
374 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
380 spin_lock(&resv->lock);
381 list_add(&trg->link, &resv->region_cache);
382 resv->region_cache_count++;
386 /* Locate the region we are before or in. */
387 list_for_each_entry(rg, head, link)
391 /* If we are below the current region then a new region is required.
392 * Subtle, allocate a new region at the position but make it zero
393 * size such that we can guarantee to record the reservation. */
394 if (&rg->link == head || t < rg->from) {
396 resv->adds_in_progress--;
397 spin_unlock(&resv->lock);
398 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
404 INIT_LIST_HEAD(&nrg->link);
408 list_add(&nrg->link, rg->link.prev);
413 /* Round our left edge to the current segment if it encloses us. */
418 /* Check for and consume any regions we now overlap with. */
419 list_for_each_entry(rg, rg->link.prev, link) {
420 if (&rg->link == head)
425 /* We overlap with this area, if it extends further than
426 * us then we must extend ourselves. Account for its
427 * existing reservation. */
432 chg -= rg->to - rg->from;
436 spin_unlock(&resv->lock);
437 /* We already know we raced and no longer need the new region */
441 spin_unlock(&resv->lock);
446 * Abort the in progress add operation. The adds_in_progress field
447 * of the resv_map keeps track of the operations in progress between
448 * calls to region_chg and region_add. Operations are sometimes
449 * aborted after the call to region_chg. In such cases, region_abort
450 * is called to decrement the adds_in_progress counter.
452 * NOTE: The range arguments [f, t) are not needed or used in this
453 * routine. They are kept to make reading the calling code easier as
454 * arguments will match the associated region_chg call.
456 static void region_abort(struct resv_map *resv, long f, long t)
458 spin_lock(&resv->lock);
459 VM_BUG_ON(!resv->region_cache_count);
460 resv->adds_in_progress--;
461 spin_unlock(&resv->lock);
465 * Delete the specified range [f, t) from the reserve map. If the
466 * t parameter is LONG_MAX, this indicates that ALL regions after f
467 * should be deleted. Locate the regions which intersect [f, t)
468 * and either trim, delete or split the existing regions.
470 * Returns the number of huge pages deleted from the reserve map.
471 * In the normal case, the return value is zero or more. In the
472 * case where a region must be split, a new region descriptor must
473 * be allocated. If the allocation fails, -ENOMEM will be returned.
474 * NOTE: If the parameter t == LONG_MAX, then we will never split
475 * a region and possibly return -ENOMEM. Callers specifying
476 * t == LONG_MAX do not need to check for -ENOMEM error.
478 static long region_del(struct resv_map *resv, long f, long t)
480 struct list_head *head = &resv->regions;
481 struct file_region *rg, *trg;
482 struct file_region *nrg = NULL;
486 spin_lock(&resv->lock);
487 list_for_each_entry_safe(rg, trg, head, link) {
489 * Skip regions before the range to be deleted. file_region
490 * ranges are normally of the form [from, to). However, there
491 * may be a "placeholder" entry in the map which is of the form
492 * (from, to) with from == to. Check for placeholder entries
493 * at the beginning of the range to be deleted.
495 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
501 if (f > rg->from && t < rg->to) { /* Must split region */
503 * Check for an entry in the cache before dropping
504 * lock and attempting allocation.
507 resv->region_cache_count > resv->adds_in_progress) {
508 nrg = list_first_entry(&resv->region_cache,
511 list_del(&nrg->link);
512 resv->region_cache_count--;
516 spin_unlock(&resv->lock);
517 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
525 /* New entry for end of split region */
528 INIT_LIST_HEAD(&nrg->link);
530 /* Original entry is trimmed */
533 list_add(&nrg->link, &rg->link);
538 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
539 del += rg->to - rg->from;
545 if (f <= rg->from) { /* Trim beginning of region */
548 } else { /* Trim end of region */
554 spin_unlock(&resv->lock);
560 * A rare out of memory error was encountered which prevented removal of
561 * the reserve map region for a page. The huge page itself was free'ed
562 * and removed from the page cache. This routine will adjust the subpool
563 * usage count, and the global reserve count if needed. By incrementing
564 * these counts, the reserve map entry which could not be deleted will
565 * appear as a "reserved" entry instead of simply dangling with incorrect
568 void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve)
570 struct hugepage_subpool *spool = subpool_inode(inode);
573 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
574 if (restore_reserve && rsv_adjust) {
575 struct hstate *h = hstate_inode(inode);
577 hugetlb_acct_memory(h, 1);
582 * Count and return the number of huge pages in the reserve map
583 * that intersect with the range [f, t).
585 static long region_count(struct resv_map *resv, long f, long t)
587 struct list_head *head = &resv->regions;
588 struct file_region *rg;
591 spin_lock(&resv->lock);
592 /* Locate each segment we overlap with, and count that overlap. */
593 list_for_each_entry(rg, head, link) {
602 seg_from = max(rg->from, f);
603 seg_to = min(rg->to, t);
605 chg += seg_to - seg_from;
607 spin_unlock(&resv->lock);
613 * Convert the address within this vma to the page offset within
614 * the mapping, in pagecache page units; huge pages here.
616 static pgoff_t vma_hugecache_offset(struct hstate *h,
617 struct vm_area_struct *vma, unsigned long address)
619 return ((address - vma->vm_start) >> huge_page_shift(h)) +
620 (vma->vm_pgoff >> huge_page_order(h));
623 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
624 unsigned long address)
626 return vma_hugecache_offset(hstate_vma(vma), vma, address);
630 * Return the size of the pages allocated when backing a VMA. In the majority
631 * cases this will be same size as used by the page table entries.
633 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
635 struct hstate *hstate;
637 if (!is_vm_hugetlb_page(vma))
640 hstate = hstate_vma(vma);
642 return 1UL << huge_page_shift(hstate);
644 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
647 * Return the page size being used by the MMU to back a VMA. In the majority
648 * of cases, the page size used by the kernel matches the MMU size. On
649 * architectures where it differs, an architecture-specific version of this
650 * function is required.
652 #ifndef vma_mmu_pagesize
653 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
655 return vma_kernel_pagesize(vma);
660 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
661 * bits of the reservation map pointer, which are always clear due to
664 #define HPAGE_RESV_OWNER (1UL << 0)
665 #define HPAGE_RESV_UNMAPPED (1UL << 1)
666 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
669 * These helpers are used to track how many pages are reserved for
670 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
671 * is guaranteed to have their future faults succeed.
673 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
674 * the reserve counters are updated with the hugetlb_lock held. It is safe
675 * to reset the VMA at fork() time as it is not in use yet and there is no
676 * chance of the global counters getting corrupted as a result of the values.
678 * The private mapping reservation is represented in a subtly different
679 * manner to a shared mapping. A shared mapping has a region map associated
680 * with the underlying file, this region map represents the backing file
681 * pages which have ever had a reservation assigned which this persists even
682 * after the page is instantiated. A private mapping has a region map
683 * associated with the original mmap which is attached to all VMAs which
684 * reference it, this region map represents those offsets which have consumed
685 * reservation ie. where pages have been instantiated.
687 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
689 return (unsigned long)vma->vm_private_data;
692 static void set_vma_private_data(struct vm_area_struct *vma,
695 vma->vm_private_data = (void *)value;
698 struct resv_map *resv_map_alloc(void)
700 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
701 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
703 if (!resv_map || !rg) {
709 kref_init(&resv_map->refs);
710 spin_lock_init(&resv_map->lock);
711 INIT_LIST_HEAD(&resv_map->regions);
713 resv_map->adds_in_progress = 0;
715 INIT_LIST_HEAD(&resv_map->region_cache);
716 list_add(&rg->link, &resv_map->region_cache);
717 resv_map->region_cache_count = 1;
722 void resv_map_release(struct kref *ref)
724 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
725 struct list_head *head = &resv_map->region_cache;
726 struct file_region *rg, *trg;
728 /* Clear out any active regions before we release the map. */
729 region_del(resv_map, 0, LONG_MAX);
731 /* ... and any entries left in the cache */
732 list_for_each_entry_safe(rg, trg, head, link) {
737 VM_BUG_ON(resv_map->adds_in_progress);
742 static inline struct resv_map *inode_resv_map(struct inode *inode)
744 return inode->i_mapping->private_data;
747 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
749 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
750 if (vma->vm_flags & VM_MAYSHARE) {
751 struct address_space *mapping = vma->vm_file->f_mapping;
752 struct inode *inode = mapping->host;
754 return inode_resv_map(inode);
757 return (struct resv_map *)(get_vma_private_data(vma) &
762 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
764 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
765 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
767 set_vma_private_data(vma, (get_vma_private_data(vma) &
768 HPAGE_RESV_MASK) | (unsigned long)map);
771 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
773 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
774 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
776 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
779 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
781 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
783 return (get_vma_private_data(vma) & flag) != 0;
786 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
787 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
789 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
790 if (!(vma->vm_flags & VM_MAYSHARE))
791 vma->vm_private_data = (void *)0;
794 /* Returns true if the VMA has associated reserve pages */
795 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
797 if (vma->vm_flags & VM_NORESERVE) {
799 * This address is already reserved by other process(chg == 0),
800 * so, we should decrement reserved count. Without decrementing,
801 * reserve count remains after releasing inode, because this
802 * allocated page will go into page cache and is regarded as
803 * coming from reserved pool in releasing step. Currently, we
804 * don't have any other solution to deal with this situation
805 * properly, so add work-around here.
807 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
813 /* Shared mappings always use reserves */
814 if (vma->vm_flags & VM_MAYSHARE) {
816 * We know VM_NORESERVE is not set. Therefore, there SHOULD
817 * be a region map for all pages. The only situation where
818 * there is no region map is if a hole was punched via
819 * fallocate. In this case, there really are no reverves to
820 * use. This situation is indicated if chg != 0.
829 * Only the process that called mmap() has reserves for
832 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
838 static void enqueue_huge_page(struct hstate *h, struct page *page)
840 int nid = page_to_nid(page);
841 list_move(&page->lru, &h->hugepage_freelists[nid]);
842 h->free_huge_pages++;
843 h->free_huge_pages_node[nid]++;
846 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
850 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
851 if (!is_migrate_isolate_page(page))
854 * if 'non-isolated free hugepage' not found on the list,
855 * the allocation fails.
857 if (&h->hugepage_freelists[nid] == &page->lru)
859 list_move(&page->lru, &h->hugepage_activelist);
860 set_page_refcounted(page);
861 h->free_huge_pages--;
862 h->free_huge_pages_node[nid]--;
866 /* Movability of hugepages depends on migration support. */
867 static inline gfp_t htlb_alloc_mask(struct hstate *h)
869 if (hugepages_treat_as_movable || hugepage_migration_supported(h))
870 return GFP_HIGHUSER_MOVABLE;
875 static struct page *dequeue_huge_page_vma(struct hstate *h,
876 struct vm_area_struct *vma,
877 unsigned long address, int avoid_reserve,
880 struct page *page = NULL;
881 struct mempolicy *mpol;
882 nodemask_t *nodemask;
883 struct zonelist *zonelist;
886 unsigned int cpuset_mems_cookie;
889 * A child process with MAP_PRIVATE mappings created by their parent
890 * have no page reserves. This check ensures that reservations are
891 * not "stolen". The child may still get SIGKILLed
893 if (!vma_has_reserves(vma, chg) &&
894 h->free_huge_pages - h->resv_huge_pages == 0)
897 /* If reserves cannot be used, ensure enough pages are in the pool */
898 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
902 cpuset_mems_cookie = read_mems_allowed_begin();
903 zonelist = huge_zonelist(vma, address,
904 htlb_alloc_mask(h), &mpol, &nodemask);
906 for_each_zone_zonelist_nodemask(zone, z, zonelist,
907 MAX_NR_ZONES - 1, nodemask) {
908 if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
909 page = dequeue_huge_page_node(h, zone_to_nid(zone));
913 if (!vma_has_reserves(vma, chg))
916 SetPagePrivate(page);
917 h->resv_huge_pages--;
924 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
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(nid, *nodes_allowed);
942 if (nid == MAX_NUMNODES)
943 nid = first_node(*nodes_allowed);
944 VM_BUG_ON(nid >= MAX_NUMNODES);
949 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
951 if (!node_isset(nid, *nodes_allowed))
952 nid = next_node_allowed(nid, nodes_allowed);
957 * returns the previously saved node ["this node"] from which to
958 * allocate a persistent huge page for the pool and advance the
959 * next node from which to allocate, handling wrap at end of node
962 static int hstate_next_node_to_alloc(struct hstate *h,
963 nodemask_t *nodes_allowed)
967 VM_BUG_ON(!nodes_allowed);
969 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
970 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
976 * helper for free_pool_huge_page() - return the previously saved
977 * node ["this node"] from which to free a huge page. Advance the
978 * next node id whether or not we find a free huge page to free so
979 * that the next attempt to free addresses the next node.
981 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
985 VM_BUG_ON(!nodes_allowed);
987 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
988 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
993 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
994 for (nr_nodes = nodes_weight(*mask); \
996 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
999 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1000 for (nr_nodes = nodes_weight(*mask); \
1002 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1005 #if defined(CONFIG_CMA) && defined(CONFIG_X86_64)
1006 static void destroy_compound_gigantic_page(struct page *page,
1010 int nr_pages = 1 << order;
1011 struct page *p = page + 1;
1013 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1014 clear_compound_head(p);
1015 set_page_refcounted(p);
1018 set_compound_order(page, 0);
1019 __ClearPageHead(page);
1022 static void free_gigantic_page(struct page *page, unsigned int order)
1024 free_contig_range(page_to_pfn(page), 1 << order);
1027 static int __alloc_gigantic_page(unsigned long start_pfn,
1028 unsigned long nr_pages)
1030 unsigned long end_pfn = start_pfn + nr_pages;
1031 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1034 static bool pfn_range_valid_gigantic(unsigned long start_pfn,
1035 unsigned long nr_pages)
1037 unsigned long i, end_pfn = start_pfn + nr_pages;
1040 for (i = start_pfn; i < end_pfn; i++) {
1044 page = pfn_to_page(i);
1046 if (PageReserved(page))
1049 if (page_count(page) > 0)
1059 static bool zone_spans_last_pfn(const struct zone *zone,
1060 unsigned long start_pfn, unsigned long nr_pages)
1062 unsigned long last_pfn = start_pfn + nr_pages - 1;
1063 return zone_spans_pfn(zone, last_pfn);
1066 static struct page *alloc_gigantic_page(int nid, unsigned int order)
1068 unsigned long nr_pages = 1 << order;
1069 unsigned long ret, pfn, flags;
1072 z = NODE_DATA(nid)->node_zones;
1073 for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
1074 spin_lock_irqsave(&z->lock, flags);
1076 pfn = ALIGN(z->zone_start_pfn, nr_pages);
1077 while (zone_spans_last_pfn(z, pfn, nr_pages)) {
1078 if (pfn_range_valid_gigantic(pfn, nr_pages)) {
1080 * We release the zone lock here because
1081 * alloc_contig_range() will also lock the zone
1082 * at some point. If there's an allocation
1083 * spinning on this lock, it may win the race
1084 * and cause alloc_contig_range() to fail...
1086 spin_unlock_irqrestore(&z->lock, flags);
1087 ret = __alloc_gigantic_page(pfn, nr_pages);
1089 return pfn_to_page(pfn);
1090 spin_lock_irqsave(&z->lock, flags);
1095 spin_unlock_irqrestore(&z->lock, flags);
1101 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1102 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1104 static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
1108 page = alloc_gigantic_page(nid, huge_page_order(h));
1110 prep_compound_gigantic_page(page, huge_page_order(h));
1111 prep_new_huge_page(h, page, nid);
1117 static int alloc_fresh_gigantic_page(struct hstate *h,
1118 nodemask_t *nodes_allowed)
1120 struct page *page = NULL;
1123 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1124 page = alloc_fresh_gigantic_page_node(h, node);
1132 static inline bool gigantic_page_supported(void) { return true; }
1134 static inline bool gigantic_page_supported(void) { return false; }
1135 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1136 static inline void destroy_compound_gigantic_page(struct page *page,
1137 unsigned int order) { }
1138 static inline int alloc_fresh_gigantic_page(struct hstate *h,
1139 nodemask_t *nodes_allowed) { return 0; }
1142 static void update_and_free_page(struct hstate *h, struct page *page)
1146 if (hstate_is_gigantic(h) && !gigantic_page_supported())
1150 h->nr_huge_pages_node[page_to_nid(page)]--;
1151 for (i = 0; i < pages_per_huge_page(h); i++) {
1152 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1153 1 << PG_referenced | 1 << PG_dirty |
1154 1 << PG_active | 1 << PG_private |
1157 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1158 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1159 set_page_refcounted(page);
1160 if (hstate_is_gigantic(h)) {
1161 destroy_compound_gigantic_page(page, huge_page_order(h));
1162 free_gigantic_page(page, huge_page_order(h));
1164 __free_pages(page, huge_page_order(h));
1168 struct hstate *size_to_hstate(unsigned long size)
1172 for_each_hstate(h) {
1173 if (huge_page_size(h) == size)
1180 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1181 * to hstate->hugepage_activelist.)
1183 * This function can be called for tail pages, but never returns true for them.
1185 bool page_huge_active(struct page *page)
1187 VM_BUG_ON_PAGE(!PageHuge(page), page);
1188 return PageHead(page) && PagePrivate(&page[1]);
1191 /* never called for tail page */
1192 static void set_page_huge_active(struct page *page)
1194 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1195 SetPagePrivate(&page[1]);
1198 static void clear_page_huge_active(struct page *page)
1200 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1201 ClearPagePrivate(&page[1]);
1204 void free_huge_page(struct page *page)
1207 * Can't pass hstate in here because it is called from the
1208 * compound page destructor.
1210 struct hstate *h = page_hstate(page);
1211 int nid = page_to_nid(page);
1212 struct hugepage_subpool *spool =
1213 (struct hugepage_subpool *)page_private(page);
1214 bool restore_reserve;
1216 set_page_private(page, 0);
1217 page->mapping = NULL;
1218 BUG_ON(page_count(page));
1219 BUG_ON(page_mapcount(page));
1220 restore_reserve = PagePrivate(page);
1221 ClearPagePrivate(page);
1224 * A return code of zero implies that the subpool will be under its
1225 * minimum size if the reservation is not restored after page is free.
1226 * Therefore, force restore_reserve operation.
1228 if (hugepage_subpool_put_pages(spool, 1) == 0)
1229 restore_reserve = true;
1231 spin_lock(&hugetlb_lock);
1232 clear_page_huge_active(page);
1233 hugetlb_cgroup_uncharge_page(hstate_index(h),
1234 pages_per_huge_page(h), page);
1235 if (restore_reserve)
1236 h->resv_huge_pages++;
1238 if (h->surplus_huge_pages_node[nid]) {
1239 /* remove the page from active list */
1240 list_del(&page->lru);
1241 update_and_free_page(h, page);
1242 h->surplus_huge_pages--;
1243 h->surplus_huge_pages_node[nid]--;
1245 arch_clear_hugepage_flags(page);
1246 enqueue_huge_page(h, page);
1248 spin_unlock(&hugetlb_lock);
1251 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1253 INIT_LIST_HEAD(&page->lru);
1254 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1255 spin_lock(&hugetlb_lock);
1256 set_hugetlb_cgroup(page, NULL);
1258 h->nr_huge_pages_node[nid]++;
1259 spin_unlock(&hugetlb_lock);
1260 put_page(page); /* free it into the hugepage allocator */
1263 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1266 int nr_pages = 1 << order;
1267 struct page *p = page + 1;
1269 /* we rely on prep_new_huge_page to set the destructor */
1270 set_compound_order(page, order);
1271 __SetPageHead(page);
1272 __ClearPageReserved(page);
1273 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1275 * For gigantic hugepages allocated through bootmem at
1276 * boot, it's safer to be consistent with the not-gigantic
1277 * hugepages and clear the PG_reserved bit from all tail pages
1278 * too. Otherwse drivers using get_user_pages() to access tail
1279 * pages may get the reference counting wrong if they see
1280 * PG_reserved set on a tail page (despite the head page not
1281 * having PG_reserved set). Enforcing this consistency between
1282 * head and tail pages allows drivers to optimize away a check
1283 * on the head page when they need know if put_page() is needed
1284 * after get_user_pages().
1286 __ClearPageReserved(p);
1287 set_page_count(p, 0);
1288 set_compound_head(p, page);
1293 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1294 * transparent huge pages. See the PageTransHuge() documentation for more
1297 int PageHuge(struct page *page)
1299 if (!PageCompound(page))
1302 page = compound_head(page);
1303 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1305 EXPORT_SYMBOL_GPL(PageHuge);
1308 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1309 * normal or transparent huge pages.
1311 int PageHeadHuge(struct page *page_head)
1313 if (!PageHead(page_head))
1316 return get_compound_page_dtor(page_head) == free_huge_page;
1319 pgoff_t __basepage_index(struct page *page)
1321 struct page *page_head = compound_head(page);
1322 pgoff_t index = page_index(page_head);
1323 unsigned long compound_idx;
1325 if (!PageHuge(page_head))
1326 return page_index(page);
1328 if (compound_order(page_head) >= MAX_ORDER)
1329 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1331 compound_idx = page - page_head;
1333 return (index << compound_order(page_head)) + compound_idx;
1336 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
1340 page = __alloc_pages_node(nid,
1341 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1342 __GFP_REPEAT|__GFP_NOWARN,
1343 huge_page_order(h));
1345 prep_new_huge_page(h, page, nid);
1351 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1357 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1358 page = alloc_fresh_huge_page_node(h, node);
1366 count_vm_event(HTLB_BUDDY_PGALLOC);
1368 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1374 * Free huge page from pool from next node to free.
1375 * Attempt to keep persistent huge pages more or less
1376 * balanced over allowed nodes.
1377 * Called with hugetlb_lock locked.
1379 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1385 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1387 * If we're returning unused surplus pages, only examine
1388 * nodes with surplus pages.
1390 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1391 !list_empty(&h->hugepage_freelists[node])) {
1393 list_entry(h->hugepage_freelists[node].next,
1395 list_del(&page->lru);
1396 h->free_huge_pages--;
1397 h->free_huge_pages_node[node]--;
1399 h->surplus_huge_pages--;
1400 h->surplus_huge_pages_node[node]--;
1402 update_and_free_page(h, page);
1412 * Dissolve a given free hugepage into free buddy pages. This function does
1413 * nothing for in-use (including surplus) hugepages.
1415 static void dissolve_free_huge_page(struct page *page)
1417 spin_lock(&hugetlb_lock);
1418 if (PageHuge(page) && !page_count(page)) {
1419 struct page *head = compound_head(page);
1420 struct hstate *h = page_hstate(head);
1421 int nid = page_to_nid(head);
1422 list_del(&head->lru);
1423 h->free_huge_pages--;
1424 h->free_huge_pages_node[nid]--;
1425 update_and_free_page(h, head);
1427 spin_unlock(&hugetlb_lock);
1431 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1432 * make specified memory blocks removable from the system.
1433 * Note that this will dissolve a free gigantic hugepage completely, if any
1434 * part of it lies within the given range.
1436 void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1440 if (!hugepages_supported())
1443 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order)
1444 dissolve_free_huge_page(pfn_to_page(pfn));
1448 * There are 3 ways this can get called:
1449 * 1. With vma+addr: we use the VMA's memory policy
1450 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1451 * page from any node, and let the buddy allocator itself figure
1453 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1454 * strictly from 'nid'
1456 static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
1457 struct vm_area_struct *vma, unsigned long addr, int nid)
1459 int order = huge_page_order(h);
1460 gfp_t gfp = htlb_alloc_mask(h)|__GFP_COMP|__GFP_REPEAT|__GFP_NOWARN;
1461 unsigned int cpuset_mems_cookie;
1464 * We need a VMA to get a memory policy. If we do not
1465 * have one, we use the 'nid' argument.
1467 * The mempolicy stuff below has some non-inlined bits
1468 * and calls ->vm_ops. That makes it hard to optimize at
1469 * compile-time, even when NUMA is off and it does
1470 * nothing. This helps the compiler optimize it out.
1472 if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1474 * If a specific node is requested, make sure to
1475 * get memory from there, but only when a node
1476 * is explicitly specified.
1478 if (nid != NUMA_NO_NODE)
1479 gfp |= __GFP_THISNODE;
1481 * Make sure to call something that can handle
1484 return alloc_pages_node(nid, gfp, order);
1488 * OK, so we have a VMA. Fetch the mempolicy and try to
1489 * allocate a huge page with it. We will only reach this
1490 * when CONFIG_NUMA=y.
1494 struct mempolicy *mpol;
1495 struct zonelist *zl;
1496 nodemask_t *nodemask;
1498 cpuset_mems_cookie = read_mems_allowed_begin();
1499 zl = huge_zonelist(vma, addr, gfp, &mpol, &nodemask);
1500 mpol_cond_put(mpol);
1501 page = __alloc_pages_nodemask(gfp, order, zl, nodemask);
1504 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1510 * There are two ways to allocate a huge page:
1511 * 1. When you have a VMA and an address (like a fault)
1512 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1514 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1515 * this case which signifies that the allocation should be done with
1516 * respect for the VMA's memory policy.
1518 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1519 * implies that memory policies will not be taken in to account.
1521 static struct page *__alloc_buddy_huge_page(struct hstate *h,
1522 struct vm_area_struct *vma, unsigned long addr, int nid)
1527 if (hstate_is_gigantic(h))
1531 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1532 * This makes sure the caller is picking _one_ of the modes with which
1533 * we can call this function, not both.
1535 if (vma || (addr != -1)) {
1536 VM_WARN_ON_ONCE(addr == -1);
1537 VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1540 * Assume we will successfully allocate the surplus page to
1541 * prevent racing processes from causing the surplus to exceed
1544 * This however introduces a different race, where a process B
1545 * tries to grow the static hugepage pool while alloc_pages() is
1546 * called by process A. B will only examine the per-node
1547 * counters in determining if surplus huge pages can be
1548 * converted to normal huge pages in adjust_pool_surplus(). A
1549 * won't be able to increment the per-node counter, until the
1550 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1551 * no more huge pages can be converted from surplus to normal
1552 * state (and doesn't try to convert again). Thus, we have a
1553 * case where a surplus huge page exists, the pool is grown, and
1554 * the surplus huge page still exists after, even though it
1555 * should just have been converted to a normal huge page. This
1556 * does not leak memory, though, as the hugepage will be freed
1557 * once it is out of use. It also does not allow the counters to
1558 * go out of whack in adjust_pool_surplus() as we don't modify
1559 * the node values until we've gotten the hugepage and only the
1560 * per-node value is checked there.
1562 spin_lock(&hugetlb_lock);
1563 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1564 spin_unlock(&hugetlb_lock);
1568 h->surplus_huge_pages++;
1570 spin_unlock(&hugetlb_lock);
1572 page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1574 spin_lock(&hugetlb_lock);
1576 INIT_LIST_HEAD(&page->lru);
1577 r_nid = page_to_nid(page);
1578 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1579 set_hugetlb_cgroup(page, NULL);
1581 * We incremented the global counters already
1583 h->nr_huge_pages_node[r_nid]++;
1584 h->surplus_huge_pages_node[r_nid]++;
1585 __count_vm_event(HTLB_BUDDY_PGALLOC);
1588 h->surplus_huge_pages--;
1589 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1591 spin_unlock(&hugetlb_lock);
1597 * Allocate a huge page from 'nid'. Note, 'nid' may be
1598 * NUMA_NO_NODE, which means that it may be allocated
1602 struct page *__alloc_buddy_huge_page_no_mpol(struct hstate *h, int nid)
1604 unsigned long addr = -1;
1606 return __alloc_buddy_huge_page(h, NULL, addr, nid);
1610 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1613 struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
1614 struct vm_area_struct *vma, unsigned long addr)
1616 return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
1620 * This allocation function is useful in the context where vma is irrelevant.
1621 * E.g. soft-offlining uses this function because it only cares physical
1622 * address of error page.
1624 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1626 struct page *page = NULL;
1628 spin_lock(&hugetlb_lock);
1629 if (h->free_huge_pages - h->resv_huge_pages > 0)
1630 page = dequeue_huge_page_node(h, nid);
1631 spin_unlock(&hugetlb_lock);
1634 page = __alloc_buddy_huge_page_no_mpol(h, nid);
1640 * Increase the hugetlb pool such that it can accommodate a reservation
1643 static int gather_surplus_pages(struct hstate *h, int delta)
1645 struct list_head surplus_list;
1646 struct page *page, *tmp;
1648 int needed, allocated;
1649 bool alloc_ok = true;
1651 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1653 h->resv_huge_pages += delta;
1658 INIT_LIST_HEAD(&surplus_list);
1662 spin_unlock(&hugetlb_lock);
1663 for (i = 0; i < needed; i++) {
1664 page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1669 list_add(&page->lru, &surplus_list);
1674 * After retaking hugetlb_lock, we need to recalculate 'needed'
1675 * because either resv_huge_pages or free_huge_pages may have changed.
1677 spin_lock(&hugetlb_lock);
1678 needed = (h->resv_huge_pages + delta) -
1679 (h->free_huge_pages + allocated);
1684 * We were not able to allocate enough pages to
1685 * satisfy the entire reservation so we free what
1686 * we've allocated so far.
1691 * The surplus_list now contains _at_least_ the number of extra pages
1692 * needed to accommodate the reservation. Add the appropriate number
1693 * of pages to the hugetlb pool and free the extras back to the buddy
1694 * allocator. Commit the entire reservation here to prevent another
1695 * process from stealing the pages as they are added to the pool but
1696 * before they are reserved.
1698 needed += allocated;
1699 h->resv_huge_pages += delta;
1702 /* Free the needed pages to the hugetlb pool */
1703 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1707 * This page is now managed by the hugetlb allocator and has
1708 * no users -- drop the buddy allocator's reference.
1710 put_page_testzero(page);
1711 VM_BUG_ON_PAGE(page_count(page), page);
1712 enqueue_huge_page(h, page);
1715 spin_unlock(&hugetlb_lock);
1717 /* Free unnecessary surplus pages to the buddy allocator */
1718 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1720 spin_lock(&hugetlb_lock);
1726 * When releasing a hugetlb pool reservation, any surplus pages that were
1727 * allocated to satisfy the reservation must be explicitly freed if they were
1729 * Called with hugetlb_lock held.
1731 static void return_unused_surplus_pages(struct hstate *h,
1732 unsigned long unused_resv_pages)
1734 unsigned long nr_pages;
1736 /* Uncommit the reservation */
1737 h->resv_huge_pages -= unused_resv_pages;
1739 /* Cannot return gigantic pages currently */
1740 if (hstate_is_gigantic(h))
1743 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1746 * We want to release as many surplus pages as possible, spread
1747 * evenly across all nodes with memory. Iterate across these nodes
1748 * until we can no longer free unreserved surplus pages. This occurs
1749 * when the nodes with surplus pages have no free pages.
1750 * free_pool_huge_page() will balance the the freed pages across the
1751 * on-line nodes with memory and will handle the hstate accounting.
1753 while (nr_pages--) {
1754 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1756 cond_resched_lock(&hugetlb_lock);
1762 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1763 * are used by the huge page allocation routines to manage reservations.
1765 * vma_needs_reservation is called to determine if the huge page at addr
1766 * within the vma has an associated reservation. If a reservation is
1767 * needed, the value 1 is returned. The caller is then responsible for
1768 * managing the global reservation and subpool usage counts. After
1769 * the huge page has been allocated, vma_commit_reservation is called
1770 * to add the page to the reservation map. If the page allocation fails,
1771 * the reservation must be ended instead of committed. vma_end_reservation
1772 * is called in such cases.
1774 * In the normal case, vma_commit_reservation returns the same value
1775 * as the preceding vma_needs_reservation call. The only time this
1776 * is not the case is if a reserve map was changed between calls. It
1777 * is the responsibility of the caller to notice the difference and
1778 * take appropriate action.
1780 enum vma_resv_mode {
1785 static long __vma_reservation_common(struct hstate *h,
1786 struct vm_area_struct *vma, unsigned long addr,
1787 enum vma_resv_mode mode)
1789 struct resv_map *resv;
1793 resv = vma_resv_map(vma);
1797 idx = vma_hugecache_offset(h, vma, addr);
1799 case VMA_NEEDS_RESV:
1800 ret = region_chg(resv, idx, idx + 1);
1802 case VMA_COMMIT_RESV:
1803 ret = region_add(resv, idx, idx + 1);
1806 region_abort(resv, idx, idx + 1);
1813 if (vma->vm_flags & VM_MAYSHARE)
1816 return ret < 0 ? ret : 0;
1819 static long vma_needs_reservation(struct hstate *h,
1820 struct vm_area_struct *vma, unsigned long addr)
1822 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1825 static long vma_commit_reservation(struct hstate *h,
1826 struct vm_area_struct *vma, unsigned long addr)
1828 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
1831 static void vma_end_reservation(struct hstate *h,
1832 struct vm_area_struct *vma, unsigned long addr)
1834 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1837 struct page *alloc_huge_page(struct vm_area_struct *vma,
1838 unsigned long addr, int avoid_reserve)
1840 struct hugepage_subpool *spool = subpool_vma(vma);
1841 struct hstate *h = hstate_vma(vma);
1843 long map_chg, map_commit;
1846 struct hugetlb_cgroup *h_cg;
1848 idx = hstate_index(h);
1850 * Examine the region/reserve map to determine if the process
1851 * has a reservation for the page to be allocated. A return
1852 * code of zero indicates a reservation exists (no change).
1854 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
1856 return ERR_PTR(-ENOMEM);
1859 * Processes that did not create the mapping will have no
1860 * reserves as indicated by the region/reserve map. Check
1861 * that the allocation will not exceed the subpool limit.
1862 * Allocations for MAP_NORESERVE mappings also need to be
1863 * checked against any subpool limit.
1865 if (map_chg || avoid_reserve) {
1866 gbl_chg = hugepage_subpool_get_pages(spool, 1);
1868 vma_end_reservation(h, vma, addr);
1869 return ERR_PTR(-ENOSPC);
1873 * Even though there was no reservation in the region/reserve
1874 * map, there could be reservations associated with the
1875 * subpool that can be used. This would be indicated if the
1876 * return value of hugepage_subpool_get_pages() is zero.
1877 * However, if avoid_reserve is specified we still avoid even
1878 * the subpool reservations.
1884 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1886 goto out_subpool_put;
1888 spin_lock(&hugetlb_lock);
1890 * glb_chg is passed to indicate whether or not a page must be taken
1891 * from the global free pool (global change). gbl_chg == 0 indicates
1892 * a reservation exists for the allocation.
1894 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
1896 spin_unlock(&hugetlb_lock);
1897 page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
1899 goto out_uncharge_cgroup;
1900 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
1901 SetPagePrivate(page);
1902 h->resv_huge_pages--;
1904 spin_lock(&hugetlb_lock);
1905 list_move(&page->lru, &h->hugepage_activelist);
1908 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1909 spin_unlock(&hugetlb_lock);
1911 set_page_private(page, (unsigned long)spool);
1913 map_commit = vma_commit_reservation(h, vma, addr);
1914 if (unlikely(map_chg > map_commit)) {
1916 * The page was added to the reservation map between
1917 * vma_needs_reservation and vma_commit_reservation.
1918 * This indicates a race with hugetlb_reserve_pages.
1919 * Adjust for the subpool count incremented above AND
1920 * in hugetlb_reserve_pages for the same page. Also,
1921 * the reservation count added in hugetlb_reserve_pages
1922 * no longer applies.
1926 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
1927 hugetlb_acct_memory(h, -rsv_adjust);
1931 out_uncharge_cgroup:
1932 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
1934 if (map_chg || avoid_reserve)
1935 hugepage_subpool_put_pages(spool, 1);
1936 vma_end_reservation(h, vma, addr);
1937 return ERR_PTR(-ENOSPC);
1941 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1942 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1943 * where no ERR_VALUE is expected to be returned.
1945 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1946 unsigned long addr, int avoid_reserve)
1948 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1954 int __weak alloc_bootmem_huge_page(struct hstate *h)
1956 struct huge_bootmem_page *m;
1959 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1962 addr = memblock_virt_alloc_try_nid_nopanic(
1963 huge_page_size(h), huge_page_size(h),
1964 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1967 * Use the beginning of the huge page to store the
1968 * huge_bootmem_page struct (until gather_bootmem
1969 * puts them into the mem_map).
1978 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
1979 /* Put them into a private list first because mem_map is not up yet */
1980 list_add(&m->list, &huge_boot_pages);
1985 static void __init prep_compound_huge_page(struct page *page,
1988 if (unlikely(order > (MAX_ORDER - 1)))
1989 prep_compound_gigantic_page(page, order);
1991 prep_compound_page(page, order);
1994 /* Put bootmem huge pages into the standard lists after mem_map is up */
1995 static void __init gather_bootmem_prealloc(void)
1997 struct huge_bootmem_page *m;
1999 list_for_each_entry(m, &huge_boot_pages, list) {
2000 struct hstate *h = m->hstate;
2003 #ifdef CONFIG_HIGHMEM
2004 page = pfn_to_page(m->phys >> PAGE_SHIFT);
2005 memblock_free_late(__pa(m),
2006 sizeof(struct huge_bootmem_page));
2008 page = virt_to_page(m);
2010 WARN_ON(page_count(page) != 1);
2011 prep_compound_huge_page(page, h->order);
2012 WARN_ON(PageReserved(page));
2013 prep_new_huge_page(h, page, page_to_nid(page));
2015 * If we had gigantic hugepages allocated at boot time, we need
2016 * to restore the 'stolen' pages to totalram_pages in order to
2017 * fix confusing memory reports from free(1) and another
2018 * side-effects, like CommitLimit going negative.
2020 if (hstate_is_gigantic(h))
2021 adjust_managed_page_count(page, 1 << h->order);
2025 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2029 for (i = 0; i < h->max_huge_pages; ++i) {
2030 if (hstate_is_gigantic(h)) {
2031 if (!alloc_bootmem_huge_page(h))
2033 } else if (!alloc_fresh_huge_page(h,
2034 &node_states[N_MEMORY]))
2037 h->max_huge_pages = i;
2040 static void __init hugetlb_init_hstates(void)
2044 for_each_hstate(h) {
2045 if (minimum_order > huge_page_order(h))
2046 minimum_order = huge_page_order(h);
2048 /* oversize hugepages were init'ed in early boot */
2049 if (!hstate_is_gigantic(h))
2050 hugetlb_hstate_alloc_pages(h);
2052 VM_BUG_ON(minimum_order == UINT_MAX);
2055 static char * __init memfmt(char *buf, unsigned long n)
2057 if (n >= (1UL << 30))
2058 sprintf(buf, "%lu GB", n >> 30);
2059 else if (n >= (1UL << 20))
2060 sprintf(buf, "%lu MB", n >> 20);
2062 sprintf(buf, "%lu KB", n >> 10);
2066 static void __init report_hugepages(void)
2070 for_each_hstate(h) {
2072 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2073 memfmt(buf, huge_page_size(h)),
2074 h->free_huge_pages);
2078 #ifdef CONFIG_HIGHMEM
2079 static void try_to_free_low(struct hstate *h, unsigned long count,
2080 nodemask_t *nodes_allowed)
2084 if (hstate_is_gigantic(h))
2087 for_each_node_mask(i, *nodes_allowed) {
2088 struct page *page, *next;
2089 struct list_head *freel = &h->hugepage_freelists[i];
2090 list_for_each_entry_safe(page, next, freel, lru) {
2091 if (count >= h->nr_huge_pages)
2093 if (PageHighMem(page))
2095 list_del(&page->lru);
2096 update_and_free_page(h, page);
2097 h->free_huge_pages--;
2098 h->free_huge_pages_node[page_to_nid(page)]--;
2103 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2104 nodemask_t *nodes_allowed)
2110 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2111 * balanced by operating on them in a round-robin fashion.
2112 * Returns 1 if an adjustment was made.
2114 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2119 VM_BUG_ON(delta != -1 && delta != 1);
2122 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2123 if (h->surplus_huge_pages_node[node])
2127 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2128 if (h->surplus_huge_pages_node[node] <
2129 h->nr_huge_pages_node[node])
2136 h->surplus_huge_pages += delta;
2137 h->surplus_huge_pages_node[node] += delta;
2141 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2142 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
2143 nodemask_t *nodes_allowed)
2145 unsigned long min_count, ret;
2147 if (hstate_is_gigantic(h) && !gigantic_page_supported())
2148 return h->max_huge_pages;
2151 * Increase the pool size
2152 * First take pages out of surplus state. Then make up the
2153 * remaining difference by allocating fresh huge pages.
2155 * We might race with __alloc_buddy_huge_page() here and be unable
2156 * to convert a surplus huge page to a normal huge page. That is
2157 * not critical, though, it just means the overall size of the
2158 * pool might be one hugepage larger than it needs to be, but
2159 * within all the constraints specified by the sysctls.
2161 spin_lock(&hugetlb_lock);
2162 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2163 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2167 while (count > persistent_huge_pages(h)) {
2169 * If this allocation races such that we no longer need the
2170 * page, free_huge_page will handle it by freeing the page
2171 * and reducing the surplus.
2173 spin_unlock(&hugetlb_lock);
2175 /* yield cpu to avoid soft lockup */
2178 if (hstate_is_gigantic(h))
2179 ret = alloc_fresh_gigantic_page(h, nodes_allowed);
2181 ret = alloc_fresh_huge_page(h, nodes_allowed);
2182 spin_lock(&hugetlb_lock);
2186 /* Bail for signals. Probably ctrl-c from user */
2187 if (signal_pending(current))
2192 * Decrease the pool size
2193 * First return free pages to the buddy allocator (being careful
2194 * to keep enough around to satisfy reservations). Then place
2195 * pages into surplus state as needed so the pool will shrink
2196 * to the desired size as pages become free.
2198 * By placing pages into the surplus state independent of the
2199 * overcommit value, we are allowing the surplus pool size to
2200 * exceed overcommit. There are few sane options here. Since
2201 * __alloc_buddy_huge_page() is checking the global counter,
2202 * though, we'll note that we're not allowed to exceed surplus
2203 * and won't grow the pool anywhere else. Not until one of the
2204 * sysctls are changed, or the surplus pages go out of use.
2206 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2207 min_count = max(count, min_count);
2208 try_to_free_low(h, min_count, nodes_allowed);
2209 while (min_count < persistent_huge_pages(h)) {
2210 if (!free_pool_huge_page(h, nodes_allowed, 0))
2212 cond_resched_lock(&hugetlb_lock);
2214 while (count < persistent_huge_pages(h)) {
2215 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2219 ret = persistent_huge_pages(h);
2220 spin_unlock(&hugetlb_lock);
2224 #define HSTATE_ATTR_RO(_name) \
2225 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2227 #define HSTATE_ATTR(_name) \
2228 static struct kobj_attribute _name##_attr = \
2229 __ATTR(_name, 0644, _name##_show, _name##_store)
2231 static struct kobject *hugepages_kobj;
2232 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2234 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2236 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2240 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2241 if (hstate_kobjs[i] == kobj) {
2243 *nidp = NUMA_NO_NODE;
2247 return kobj_to_node_hstate(kobj, nidp);
2250 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2251 struct kobj_attribute *attr, char *buf)
2254 unsigned long nr_huge_pages;
2257 h = kobj_to_hstate(kobj, &nid);
2258 if (nid == NUMA_NO_NODE)
2259 nr_huge_pages = h->nr_huge_pages;
2261 nr_huge_pages = h->nr_huge_pages_node[nid];
2263 return sprintf(buf, "%lu\n", nr_huge_pages);
2266 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2267 struct hstate *h, int nid,
2268 unsigned long count, size_t len)
2271 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2273 if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2278 if (nid == NUMA_NO_NODE) {
2280 * global hstate attribute
2282 if (!(obey_mempolicy &&
2283 init_nodemask_of_mempolicy(nodes_allowed))) {
2284 NODEMASK_FREE(nodes_allowed);
2285 nodes_allowed = &node_states[N_MEMORY];
2287 } else if (nodes_allowed) {
2289 * per node hstate attribute: adjust count to global,
2290 * but restrict alloc/free to the specified node.
2292 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2293 init_nodemask_of_node(nodes_allowed, nid);
2295 nodes_allowed = &node_states[N_MEMORY];
2297 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2299 if (nodes_allowed != &node_states[N_MEMORY])
2300 NODEMASK_FREE(nodes_allowed);
2304 NODEMASK_FREE(nodes_allowed);
2308 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2309 struct kobject *kobj, const char *buf,
2313 unsigned long count;
2317 err = kstrtoul(buf, 10, &count);
2321 h = kobj_to_hstate(kobj, &nid);
2322 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2325 static ssize_t nr_hugepages_show(struct kobject *kobj,
2326 struct kobj_attribute *attr, char *buf)
2328 return nr_hugepages_show_common(kobj, attr, buf);
2331 static ssize_t nr_hugepages_store(struct kobject *kobj,
2332 struct kobj_attribute *attr, const char *buf, size_t len)
2334 return nr_hugepages_store_common(false, kobj, buf, len);
2336 HSTATE_ATTR(nr_hugepages);
2341 * hstate attribute for optionally mempolicy-based constraint on persistent
2342 * huge page alloc/free.
2344 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2345 struct kobj_attribute *attr, char *buf)
2347 return nr_hugepages_show_common(kobj, attr, buf);
2350 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2351 struct kobj_attribute *attr, const char *buf, size_t len)
2353 return nr_hugepages_store_common(true, kobj, buf, len);
2355 HSTATE_ATTR(nr_hugepages_mempolicy);
2359 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2360 struct kobj_attribute *attr, char *buf)
2362 struct hstate *h = kobj_to_hstate(kobj, NULL);
2363 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2366 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2367 struct kobj_attribute *attr, const char *buf, size_t count)
2370 unsigned long input;
2371 struct hstate *h = kobj_to_hstate(kobj, NULL);
2373 if (hstate_is_gigantic(h))
2376 err = kstrtoul(buf, 10, &input);
2380 spin_lock(&hugetlb_lock);
2381 h->nr_overcommit_huge_pages = input;
2382 spin_unlock(&hugetlb_lock);
2386 HSTATE_ATTR(nr_overcommit_hugepages);
2388 static ssize_t free_hugepages_show(struct kobject *kobj,
2389 struct kobj_attribute *attr, char *buf)
2392 unsigned long free_huge_pages;
2395 h = kobj_to_hstate(kobj, &nid);
2396 if (nid == NUMA_NO_NODE)
2397 free_huge_pages = h->free_huge_pages;
2399 free_huge_pages = h->free_huge_pages_node[nid];
2401 return sprintf(buf, "%lu\n", free_huge_pages);
2403 HSTATE_ATTR_RO(free_hugepages);
2405 static ssize_t resv_hugepages_show(struct kobject *kobj,
2406 struct kobj_attribute *attr, char *buf)
2408 struct hstate *h = kobj_to_hstate(kobj, NULL);
2409 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2411 HSTATE_ATTR_RO(resv_hugepages);
2413 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2414 struct kobj_attribute *attr, char *buf)
2417 unsigned long surplus_huge_pages;
2420 h = kobj_to_hstate(kobj, &nid);
2421 if (nid == NUMA_NO_NODE)
2422 surplus_huge_pages = h->surplus_huge_pages;
2424 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2426 return sprintf(buf, "%lu\n", surplus_huge_pages);
2428 HSTATE_ATTR_RO(surplus_hugepages);
2430 static struct attribute *hstate_attrs[] = {
2431 &nr_hugepages_attr.attr,
2432 &nr_overcommit_hugepages_attr.attr,
2433 &free_hugepages_attr.attr,
2434 &resv_hugepages_attr.attr,
2435 &surplus_hugepages_attr.attr,
2437 &nr_hugepages_mempolicy_attr.attr,
2442 static struct attribute_group hstate_attr_group = {
2443 .attrs = hstate_attrs,
2446 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2447 struct kobject **hstate_kobjs,
2448 struct attribute_group *hstate_attr_group)
2451 int hi = hstate_index(h);
2453 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2454 if (!hstate_kobjs[hi])
2457 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2459 kobject_put(hstate_kobjs[hi]);
2464 static void __init hugetlb_sysfs_init(void)
2469 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
2470 if (!hugepages_kobj)
2473 for_each_hstate(h) {
2474 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
2475 hstate_kobjs, &hstate_attr_group);
2477 pr_err("Hugetlb: Unable to add hstate %s", h->name);
2484 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2485 * with node devices in node_devices[] using a parallel array. The array
2486 * index of a node device or _hstate == node id.
2487 * This is here to avoid any static dependency of the node device driver, in
2488 * the base kernel, on the hugetlb module.
2490 struct node_hstate {
2491 struct kobject *hugepages_kobj;
2492 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2494 static struct node_hstate node_hstates[MAX_NUMNODES];
2497 * A subset of global hstate attributes for node devices
2499 static struct attribute *per_node_hstate_attrs[] = {
2500 &nr_hugepages_attr.attr,
2501 &free_hugepages_attr.attr,
2502 &surplus_hugepages_attr.attr,
2506 static struct attribute_group per_node_hstate_attr_group = {
2507 .attrs = per_node_hstate_attrs,
2511 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2512 * Returns node id via non-NULL nidp.
2514 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2518 for (nid = 0; nid < nr_node_ids; nid++) {
2519 struct node_hstate *nhs = &node_hstates[nid];
2521 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2522 if (nhs->hstate_kobjs[i] == kobj) {
2534 * Unregister hstate attributes from a single node device.
2535 * No-op if no hstate attributes attached.
2537 static void hugetlb_unregister_node(struct node *node)
2540 struct node_hstate *nhs = &node_hstates[node->dev.id];
2542 if (!nhs->hugepages_kobj)
2543 return; /* no hstate attributes */
2545 for_each_hstate(h) {
2546 int idx = hstate_index(h);
2547 if (nhs->hstate_kobjs[idx]) {
2548 kobject_put(nhs->hstate_kobjs[idx]);
2549 nhs->hstate_kobjs[idx] = NULL;
2553 kobject_put(nhs->hugepages_kobj);
2554 nhs->hugepages_kobj = NULL;
2558 * hugetlb module exit: unregister hstate attributes from node devices
2561 static void hugetlb_unregister_all_nodes(void)
2566 * disable node device registrations.
2568 register_hugetlbfs_with_node(NULL, NULL);
2571 * remove hstate attributes from any nodes that have them.
2573 for (nid = 0; nid < nr_node_ids; nid++)
2574 hugetlb_unregister_node(node_devices[nid]);
2578 * Register hstate attributes for a single node device.
2579 * No-op if attributes already registered.
2581 static void hugetlb_register_node(struct node *node)
2584 struct node_hstate *nhs = &node_hstates[node->dev.id];
2587 if (nhs->hugepages_kobj)
2588 return; /* already allocated */
2590 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2592 if (!nhs->hugepages_kobj)
2595 for_each_hstate(h) {
2596 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
2598 &per_node_hstate_attr_group);
2600 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2601 h->name, node->dev.id);
2602 hugetlb_unregister_node(node);
2609 * hugetlb init time: register hstate attributes for all registered node
2610 * devices of nodes that have memory. All on-line nodes should have
2611 * registered their associated device by this time.
2613 static void __init hugetlb_register_all_nodes(void)
2617 for_each_node_state(nid, N_MEMORY) {
2618 struct node *node = node_devices[nid];
2619 if (node->dev.id == nid)
2620 hugetlb_register_node(node);
2624 * Let the node device driver know we're here so it can
2625 * [un]register hstate attributes on node hotplug.
2627 register_hugetlbfs_with_node(hugetlb_register_node,
2628 hugetlb_unregister_node);
2630 #else /* !CONFIG_NUMA */
2632 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2640 static void hugetlb_unregister_all_nodes(void) { }
2642 static void hugetlb_register_all_nodes(void) { }
2646 static void __exit hugetlb_exit(void)
2650 hugetlb_unregister_all_nodes();
2652 for_each_hstate(h) {
2653 kobject_put(hstate_kobjs[hstate_index(h)]);
2656 kobject_put(hugepages_kobj);
2657 kfree(hugetlb_fault_mutex_table);
2659 module_exit(hugetlb_exit);
2661 static int __init hugetlb_init(void)
2665 if (!hugepages_supported())
2668 if (!size_to_hstate(default_hstate_size)) {
2669 default_hstate_size = HPAGE_SIZE;
2670 if (!size_to_hstate(default_hstate_size))
2671 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2673 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2674 if (default_hstate_max_huge_pages)
2675 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2677 hugetlb_init_hstates();
2678 gather_bootmem_prealloc();
2681 hugetlb_sysfs_init();
2682 hugetlb_register_all_nodes();
2683 hugetlb_cgroup_file_init();
2686 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2688 num_fault_mutexes = 1;
2690 hugetlb_fault_mutex_table =
2691 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2692 BUG_ON(!hugetlb_fault_mutex_table);
2694 for (i = 0; i < num_fault_mutexes; i++)
2695 mutex_init(&hugetlb_fault_mutex_table[i]);
2698 module_init(hugetlb_init);
2700 /* Should be called on processing a hugepagesz=... option */
2701 void __init hugetlb_add_hstate(unsigned int order)
2706 if (size_to_hstate(PAGE_SIZE << order)) {
2707 pr_warning("hugepagesz= specified twice, ignoring\n");
2710 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2712 h = &hstates[hugetlb_max_hstate++];
2714 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2715 h->nr_huge_pages = 0;
2716 h->free_huge_pages = 0;
2717 for (i = 0; i < MAX_NUMNODES; ++i)
2718 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2719 INIT_LIST_HEAD(&h->hugepage_activelist);
2720 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2721 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2722 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2723 huge_page_size(h)/1024);
2728 static int __init hugetlb_nrpages_setup(char *s)
2731 static unsigned long *last_mhp;
2734 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2735 * so this hugepages= parameter goes to the "default hstate".
2737 if (!hugetlb_max_hstate)
2738 mhp = &default_hstate_max_huge_pages;
2740 mhp = &parsed_hstate->max_huge_pages;
2742 if (mhp == last_mhp) {
2743 pr_warning("hugepages= specified twice without "
2744 "interleaving hugepagesz=, ignoring\n");
2748 if (sscanf(s, "%lu", mhp) <= 0)
2752 * Global state is always initialized later in hugetlb_init.
2753 * But we need to allocate >= MAX_ORDER hstates here early to still
2754 * use the bootmem allocator.
2756 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2757 hugetlb_hstate_alloc_pages(parsed_hstate);
2763 __setup("hugepages=", hugetlb_nrpages_setup);
2765 static int __init hugetlb_default_setup(char *s)
2767 default_hstate_size = memparse(s, &s);
2770 __setup("default_hugepagesz=", hugetlb_default_setup);
2772 static unsigned int cpuset_mems_nr(unsigned int *array)
2775 unsigned int nr = 0;
2777 for_each_node_mask(node, cpuset_current_mems_allowed)
2783 #ifdef CONFIG_SYSCTL
2784 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2785 struct ctl_table *table, int write,
2786 void __user *buffer, size_t *length, loff_t *ppos)
2788 struct hstate *h = &default_hstate;
2789 unsigned long tmp = h->max_huge_pages;
2792 if (!hugepages_supported())
2796 table->maxlen = sizeof(unsigned long);
2797 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2802 ret = __nr_hugepages_store_common(obey_mempolicy, h,
2803 NUMA_NO_NODE, tmp, *length);
2808 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2809 void __user *buffer, size_t *length, loff_t *ppos)
2812 return hugetlb_sysctl_handler_common(false, table, write,
2813 buffer, length, ppos);
2817 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2818 void __user *buffer, size_t *length, loff_t *ppos)
2820 return hugetlb_sysctl_handler_common(true, table, write,
2821 buffer, length, ppos);
2823 #endif /* CONFIG_NUMA */
2825 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2826 void __user *buffer,
2827 size_t *length, loff_t *ppos)
2829 struct hstate *h = &default_hstate;
2833 if (!hugepages_supported())
2836 tmp = h->nr_overcommit_huge_pages;
2838 if (write && hstate_is_gigantic(h))
2842 table->maxlen = sizeof(unsigned long);
2843 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2848 spin_lock(&hugetlb_lock);
2849 h->nr_overcommit_huge_pages = tmp;
2850 spin_unlock(&hugetlb_lock);
2856 #endif /* CONFIG_SYSCTL */
2858 void hugetlb_report_meminfo(struct seq_file *m)
2860 struct hstate *h = &default_hstate;
2861 if (!hugepages_supported())
2864 "HugePages_Total: %5lu\n"
2865 "HugePages_Free: %5lu\n"
2866 "HugePages_Rsvd: %5lu\n"
2867 "HugePages_Surp: %5lu\n"
2868 "Hugepagesize: %8lu kB\n",
2872 h->surplus_huge_pages,
2873 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2876 int hugetlb_report_node_meminfo(int nid, char *buf)
2878 struct hstate *h = &default_hstate;
2879 if (!hugepages_supported())
2882 "Node %d HugePages_Total: %5u\n"
2883 "Node %d HugePages_Free: %5u\n"
2884 "Node %d HugePages_Surp: %5u\n",
2885 nid, h->nr_huge_pages_node[nid],
2886 nid, h->free_huge_pages_node[nid],
2887 nid, h->surplus_huge_pages_node[nid]);
2890 void hugetlb_show_meminfo(void)
2895 if (!hugepages_supported())
2898 for_each_node_state(nid, N_MEMORY)
2900 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2902 h->nr_huge_pages_node[nid],
2903 h->free_huge_pages_node[nid],
2904 h->surplus_huge_pages_node[nid],
2905 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2908 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
2910 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
2911 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
2914 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2915 unsigned long hugetlb_total_pages(void)
2918 unsigned long nr_total_pages = 0;
2921 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2922 return nr_total_pages;
2925 static int hugetlb_acct_memory(struct hstate *h, long delta)
2929 spin_lock(&hugetlb_lock);
2931 * When cpuset is configured, it breaks the strict hugetlb page
2932 * reservation as the accounting is done on a global variable. Such
2933 * reservation is completely rubbish in the presence of cpuset because
2934 * the reservation is not checked against page availability for the
2935 * current cpuset. Application can still potentially OOM'ed by kernel
2936 * with lack of free htlb page in cpuset that the task is in.
2937 * Attempt to enforce strict accounting with cpuset is almost
2938 * impossible (or too ugly) because cpuset is too fluid that
2939 * task or memory node can be dynamically moved between cpusets.
2941 * The change of semantics for shared hugetlb mapping with cpuset is
2942 * undesirable. However, in order to preserve some of the semantics,
2943 * we fall back to check against current free page availability as
2944 * a best attempt and hopefully to minimize the impact of changing
2945 * semantics that cpuset has.
2948 if (gather_surplus_pages(h, delta) < 0)
2951 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2952 return_unused_surplus_pages(h, delta);
2959 return_unused_surplus_pages(h, (unsigned long) -delta);
2962 spin_unlock(&hugetlb_lock);
2966 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2968 struct resv_map *resv = vma_resv_map(vma);
2971 * This new VMA should share its siblings reservation map if present.
2972 * The VMA will only ever have a valid reservation map pointer where
2973 * it is being copied for another still existing VMA. As that VMA
2974 * has a reference to the reservation map it cannot disappear until
2975 * after this open call completes. It is therefore safe to take a
2976 * new reference here without additional locking.
2978 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2979 kref_get(&resv->refs);
2982 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2984 struct hstate *h = hstate_vma(vma);
2985 struct resv_map *resv = vma_resv_map(vma);
2986 struct hugepage_subpool *spool = subpool_vma(vma);
2987 unsigned long reserve, start, end;
2990 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2993 start = vma_hugecache_offset(h, vma, vma->vm_start);
2994 end = vma_hugecache_offset(h, vma, vma->vm_end);
2996 reserve = (end - start) - region_count(resv, start, end);
2998 kref_put(&resv->refs, resv_map_release);
3002 * Decrement reserve counts. The global reserve count may be
3003 * adjusted if the subpool has a minimum size.
3005 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3006 hugetlb_acct_memory(h, -gbl_reserve);
3011 * We cannot handle pagefaults against hugetlb pages at all. They cause
3012 * handle_mm_fault() to try to instantiate regular-sized pages in the
3013 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3016 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3022 const struct vm_operations_struct hugetlb_vm_ops = {
3023 .fault = hugetlb_vm_op_fault,
3024 .open = hugetlb_vm_op_open,
3025 .close = hugetlb_vm_op_close,
3028 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3034 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3035 vma->vm_page_prot)));
3037 entry = huge_pte_wrprotect(mk_huge_pte(page,
3038 vma->vm_page_prot));
3040 entry = pte_mkyoung(entry);
3041 entry = pte_mkhuge(entry);
3042 entry = arch_make_huge_pte(entry, vma, page, writable);
3047 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3048 unsigned long address, pte_t *ptep)
3052 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3053 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3054 update_mmu_cache(vma, address, ptep);
3057 static int is_hugetlb_entry_migration(pte_t pte)
3061 if (huge_pte_none(pte) || pte_present(pte))
3063 swp = pte_to_swp_entry(pte);
3064 if (non_swap_entry(swp) && is_migration_entry(swp))
3070 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3074 if (huge_pte_none(pte) || pte_present(pte))
3076 swp = pte_to_swp_entry(pte);
3077 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3083 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3084 struct vm_area_struct *vma)
3086 pte_t *src_pte, *dst_pte, entry;
3087 struct page *ptepage;
3090 struct hstate *h = hstate_vma(vma);
3091 unsigned long sz = huge_page_size(h);
3092 unsigned long mmun_start; /* For mmu_notifiers */
3093 unsigned long mmun_end; /* For mmu_notifiers */
3096 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3098 mmun_start = vma->vm_start;
3099 mmun_end = vma->vm_end;
3101 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
3103 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3104 spinlock_t *src_ptl, *dst_ptl;
3105 src_pte = huge_pte_offset(src, addr);
3108 dst_pte = huge_pte_alloc(dst, addr, sz);
3114 /* If the pagetables are shared don't copy or take references */
3115 if (dst_pte == src_pte)
3118 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3119 src_ptl = huge_pte_lockptr(h, src, src_pte);
3120 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3121 entry = huge_ptep_get(src_pte);
3122 if (huge_pte_none(entry)) { /* skip none entry */
3124 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3125 is_hugetlb_entry_hwpoisoned(entry))) {
3126 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3128 if (is_write_migration_entry(swp_entry) && cow) {
3130 * COW mappings require pages in both
3131 * parent and child to be set to read.
3133 make_migration_entry_read(&swp_entry);
3134 entry = swp_entry_to_pte(swp_entry);
3135 set_huge_pte_at(src, addr, src_pte, entry);
3137 set_huge_pte_at(dst, addr, dst_pte, entry);
3140 huge_ptep_set_wrprotect(src, addr, src_pte);
3141 mmu_notifier_invalidate_range(src, mmun_start,
3144 entry = huge_ptep_get(src_pte);
3145 ptepage = pte_page(entry);
3147 page_dup_rmap(ptepage);
3148 set_huge_pte_at(dst, addr, dst_pte, entry);
3149 hugetlb_count_add(pages_per_huge_page(h), dst);
3151 spin_unlock(src_ptl);
3152 spin_unlock(dst_ptl);
3156 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
3161 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3162 unsigned long start, unsigned long end,
3163 struct page *ref_page)
3165 int force_flush = 0;
3166 struct mm_struct *mm = vma->vm_mm;
3167 unsigned long address;
3172 struct hstate *h = hstate_vma(vma);
3173 unsigned long sz = huge_page_size(h);
3174 const unsigned long mmun_start = start; /* For mmu_notifiers */
3175 const unsigned long mmun_end = end; /* For mmu_notifiers */
3177 WARN_ON(!is_vm_hugetlb_page(vma));
3178 BUG_ON(start & ~huge_page_mask(h));
3179 BUG_ON(end & ~huge_page_mask(h));
3181 tlb_start_vma(tlb, vma);
3182 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3185 for (; address < end; address += sz) {
3186 ptep = huge_pte_offset(mm, address);
3190 ptl = huge_pte_lock(h, mm, ptep);
3191 if (huge_pmd_unshare(mm, &address, ptep))
3194 pte = huge_ptep_get(ptep);
3195 if (huge_pte_none(pte))
3199 * Migrating hugepage or HWPoisoned hugepage is already
3200 * unmapped and its refcount is dropped, so just clear pte here.
3202 if (unlikely(!pte_present(pte))) {
3203 huge_pte_clear(mm, address, ptep);
3207 page = pte_page(pte);
3209 * If a reference page is supplied, it is because a specific
3210 * page is being unmapped, not a range. Ensure the page we
3211 * are about to unmap is the actual page of interest.
3214 if (page != ref_page)
3218 * Mark the VMA as having unmapped its page so that
3219 * future faults in this VMA will fail rather than
3220 * looking like data was lost
3222 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3225 pte = huge_ptep_get_and_clear(mm, address, ptep);
3226 tlb_remove_tlb_entry(tlb, ptep, address);
3227 if (huge_pte_dirty(pte))
3228 set_page_dirty(page);
3230 hugetlb_count_sub(pages_per_huge_page(h), mm);
3231 page_remove_rmap(page);
3232 force_flush = !__tlb_remove_page(tlb, page);
3238 /* Bail out after unmapping reference page if supplied */
3247 * mmu_gather ran out of room to batch pages, we break out of
3248 * the PTE lock to avoid doing the potential expensive TLB invalidate
3249 * and page-free while holding it.
3254 if (address < end && !ref_page)
3257 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3258 tlb_end_vma(tlb, vma);
3261 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
3262 struct vm_area_struct *vma, unsigned long start,
3263 unsigned long end, struct page *ref_page)
3265 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
3268 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3269 * test will fail on a vma being torn down, and not grab a page table
3270 * on its way out. We're lucky that the flag has such an appropriate
3271 * name, and can in fact be safely cleared here. We could clear it
3272 * before the __unmap_hugepage_range above, but all that's necessary
3273 * is to clear it before releasing the i_mmap_rwsem. This works
3274 * because in the context this is called, the VMA is about to be
3275 * destroyed and the i_mmap_rwsem is held.
3277 vma->vm_flags &= ~VM_MAYSHARE;
3280 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3281 unsigned long end, struct page *ref_page)
3283 struct mm_struct *mm;
3284 struct mmu_gather tlb;
3288 tlb_gather_mmu(&tlb, mm, start, end);
3289 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3290 tlb_finish_mmu(&tlb, start, end);
3294 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3295 * mappping it owns the reserve page for. The intention is to unmap the page
3296 * from other VMAs and let the children be SIGKILLed if they are faulting the
3299 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
3300 struct page *page, unsigned long address)
3302 struct hstate *h = hstate_vma(vma);
3303 struct vm_area_struct *iter_vma;
3304 struct address_space *mapping;
3308 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3309 * from page cache lookup which is in HPAGE_SIZE units.
3311 address = address & huge_page_mask(h);
3312 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
3314 mapping = file_inode(vma->vm_file)->i_mapping;
3317 * Take the mapping lock for the duration of the table walk. As
3318 * this mapping should be shared between all the VMAs,
3319 * __unmap_hugepage_range() is called as the lock is already held
3321 i_mmap_lock_write(mapping);
3322 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3323 /* Do not unmap the current VMA */
3324 if (iter_vma == vma)
3328 * Shared VMAs have their own reserves and do not affect
3329 * MAP_PRIVATE accounting but it is possible that a shared
3330 * VMA is using the same page so check and skip such VMAs.
3332 if (iter_vma->vm_flags & VM_MAYSHARE)
3336 * Unmap the page from other VMAs without their own reserves.
3337 * They get marked to be SIGKILLed if they fault in these
3338 * areas. This is because a future no-page fault on this VMA
3339 * could insert a zeroed page instead of the data existing
3340 * from the time of fork. This would look like data corruption
3342 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
3343 unmap_hugepage_range(iter_vma, address,
3344 address + huge_page_size(h), page);
3346 i_mmap_unlock_write(mapping);
3350 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3351 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3352 * cannot race with other handlers or page migration.
3353 * Keep the pte_same checks anyway to make transition from the mutex easier.
3355 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3356 unsigned long address, pte_t *ptep, pte_t pte,
3357 struct page *pagecache_page, spinlock_t *ptl)
3359 struct hstate *h = hstate_vma(vma);
3360 struct page *old_page, *new_page;
3361 int ret = 0, outside_reserve = 0;
3362 unsigned long mmun_start; /* For mmu_notifiers */
3363 unsigned long mmun_end; /* For mmu_notifiers */
3365 old_page = pte_page(pte);
3368 /* If no-one else is actually using this page, avoid the copy
3369 * and just make the page writable */
3370 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3371 page_move_anon_rmap(old_page, vma, address);
3372 set_huge_ptep_writable(vma, address, ptep);
3377 * If the process that created a MAP_PRIVATE mapping is about to
3378 * perform a COW due to a shared page count, attempt to satisfy
3379 * the allocation without using the existing reserves. The pagecache
3380 * page is used to determine if the reserve at this address was
3381 * consumed or not. If reserves were used, a partial faulted mapping
3382 * at the time of fork() could consume its reserves on COW instead
3383 * of the full address range.
3385 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3386 old_page != pagecache_page)
3387 outside_reserve = 1;
3389 page_cache_get(old_page);
3392 * Drop page table lock as buddy allocator may be called. It will
3393 * be acquired again before returning to the caller, as expected.
3396 new_page = alloc_huge_page(vma, address, outside_reserve);
3398 if (IS_ERR(new_page)) {
3400 * If a process owning a MAP_PRIVATE mapping fails to COW,
3401 * it is due to references held by a child and an insufficient
3402 * huge page pool. To guarantee the original mappers
3403 * reliability, unmap the page from child processes. The child
3404 * may get SIGKILLed if it later faults.
3406 if (outside_reserve) {
3407 page_cache_release(old_page);
3408 BUG_ON(huge_pte_none(pte));
3409 unmap_ref_private(mm, vma, old_page, address);
3410 BUG_ON(huge_pte_none(pte));
3412 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3414 pte_same(huge_ptep_get(ptep), pte)))
3415 goto retry_avoidcopy;
3417 * race occurs while re-acquiring page table
3418 * lock, and our job is done.
3423 ret = (PTR_ERR(new_page) == -ENOMEM) ?
3424 VM_FAULT_OOM : VM_FAULT_SIGBUS;
3425 goto out_release_old;
3429 * When the original hugepage is shared one, it does not have
3430 * anon_vma prepared.
3432 if (unlikely(anon_vma_prepare(vma))) {
3434 goto out_release_all;
3437 copy_user_huge_page(new_page, old_page, address, vma,
3438 pages_per_huge_page(h));
3439 __SetPageUptodate(new_page);
3440 set_page_huge_active(new_page);
3442 mmun_start = address & huge_page_mask(h);
3443 mmun_end = mmun_start + huge_page_size(h);
3444 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3447 * Retake the page table lock to check for racing updates
3448 * before the page tables are altered
3451 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3452 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3453 ClearPagePrivate(new_page);
3456 huge_ptep_clear_flush(vma, address, ptep);
3457 mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3458 set_huge_pte_at(mm, address, ptep,
3459 make_huge_pte(vma, new_page, 1));
3460 page_remove_rmap(old_page);
3461 hugepage_add_new_anon_rmap(new_page, vma, address);
3462 /* Make the old page be freed below */
3463 new_page = old_page;
3466 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3468 page_cache_release(new_page);
3470 page_cache_release(old_page);
3472 spin_lock(ptl); /* Caller expects lock to be held */
3476 /* Return the pagecache page at a given address within a VMA */
3477 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
3478 struct vm_area_struct *vma, unsigned long address)
3480 struct address_space *mapping;
3483 mapping = vma->vm_file->f_mapping;
3484 idx = vma_hugecache_offset(h, vma, address);
3486 return find_lock_page(mapping, idx);
3490 * Return whether there is a pagecache page to back given address within VMA.
3491 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3493 static bool hugetlbfs_pagecache_present(struct hstate *h,
3494 struct vm_area_struct *vma, unsigned long address)
3496 struct address_space *mapping;
3500 mapping = vma->vm_file->f_mapping;
3501 idx = vma_hugecache_offset(h, vma, address);
3503 page = find_get_page(mapping, idx);
3506 return page != NULL;
3509 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
3512 struct inode *inode = mapping->host;
3513 struct hstate *h = hstate_inode(inode);
3514 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
3518 ClearPagePrivate(page);
3520 spin_lock(&inode->i_lock);
3521 inode->i_blocks += blocks_per_huge_page(h);
3522 spin_unlock(&inode->i_lock);
3526 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3527 struct address_space *mapping, pgoff_t idx,
3528 unsigned long address, pte_t *ptep, unsigned int flags)
3530 struct hstate *h = hstate_vma(vma);
3531 int ret = VM_FAULT_SIGBUS;
3539 * Currently, we are forced to kill the process in the event the
3540 * original mapper has unmapped pages from the child due to a failed
3541 * COW. Warn that such a situation has occurred as it may not be obvious
3543 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3544 pr_warning("PID %d killed due to inadequate hugepage pool\n",
3550 * Use page lock to guard against racing truncation
3551 * before we get page_table_lock.
3554 page = find_lock_page(mapping, idx);
3556 size = i_size_read(mapping->host) >> huge_page_shift(h);
3559 page = alloc_huge_page(vma, address, 0);
3561 ret = PTR_ERR(page);
3565 ret = VM_FAULT_SIGBUS;
3568 clear_huge_page(page, address, pages_per_huge_page(h));
3569 __SetPageUptodate(page);
3570 set_page_huge_active(page);
3572 if (vma->vm_flags & VM_MAYSHARE) {
3573 int err = huge_add_to_page_cache(page, mapping, idx);
3582 if (unlikely(anon_vma_prepare(vma))) {
3584 goto backout_unlocked;
3590 * If memory error occurs between mmap() and fault, some process
3591 * don't have hwpoisoned swap entry for errored virtual address.
3592 * So we need to block hugepage fault by PG_hwpoison bit check.
3594 if (unlikely(PageHWPoison(page))) {
3595 ret = VM_FAULT_HWPOISON |
3596 VM_FAULT_SET_HINDEX(hstate_index(h));
3597 goto backout_unlocked;
3602 * If we are going to COW a private mapping later, we examine the
3603 * pending reservations for this page now. This will ensure that
3604 * any allocations necessary to record that reservation occur outside
3607 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3608 if (vma_needs_reservation(h, vma, address) < 0) {
3610 goto backout_unlocked;
3612 /* Just decrements count, does not deallocate */
3613 vma_end_reservation(h, vma, address);
3616 ptl = huge_pte_lockptr(h, mm, ptep);
3618 size = i_size_read(mapping->host) >> huge_page_shift(h);
3623 if (!huge_pte_none(huge_ptep_get(ptep)))
3627 ClearPagePrivate(page);
3628 hugepage_add_new_anon_rmap(page, vma, address);
3630 page_dup_rmap(page);
3631 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
3632 && (vma->vm_flags & VM_SHARED)));
3633 set_huge_pte_at(mm, address, ptep, new_pte);
3635 hugetlb_count_add(pages_per_huge_page(h), mm);
3636 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3637 /* Optimization, do the COW without a second fault */
3638 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
3655 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3656 struct vm_area_struct *vma,
3657 struct address_space *mapping,
3658 pgoff_t idx, unsigned long address)
3660 unsigned long key[2];
3663 if (vma->vm_flags & VM_SHARED) {
3664 key[0] = (unsigned long) mapping;
3667 key[0] = (unsigned long) mm;
3668 key[1] = address >> huge_page_shift(h);
3671 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
3673 return hash & (num_fault_mutexes - 1);
3677 * For uniprocesor systems we always use a single mutex, so just
3678 * return 0 and avoid the hashing overhead.
3680 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3681 struct vm_area_struct *vma,
3682 struct address_space *mapping,
3683 pgoff_t idx, unsigned long address)
3689 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3690 unsigned long address, unsigned int flags)
3697 struct page *page = NULL;
3698 struct page *pagecache_page = NULL;
3699 struct hstate *h = hstate_vma(vma);
3700 struct address_space *mapping;
3701 int need_wait_lock = 0;
3703 address &= huge_page_mask(h);
3705 ptep = huge_pte_offset(mm, address);
3707 entry = huge_ptep_get(ptep);
3708 if (unlikely(is_hugetlb_entry_migration(entry))) {
3709 migration_entry_wait_huge(vma, mm, ptep);
3711 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3712 return VM_FAULT_HWPOISON_LARGE |
3713 VM_FAULT_SET_HINDEX(hstate_index(h));
3715 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
3717 return VM_FAULT_OOM;
3720 mapping = vma->vm_file->f_mapping;
3721 idx = vma_hugecache_offset(h, vma, address);
3724 * Serialize hugepage allocation and instantiation, so that we don't
3725 * get spurious allocation failures if two CPUs race to instantiate
3726 * the same page in the page cache.
3728 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
3729 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3731 entry = huge_ptep_get(ptep);
3732 if (huge_pte_none(entry)) {
3733 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3740 * entry could be a migration/hwpoison entry at this point, so this
3741 * check prevents the kernel from going below assuming that we have
3742 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3743 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3746 if (!pte_present(entry))
3750 * If we are going to COW the mapping later, we examine the pending
3751 * reservations for this page now. This will ensure that any
3752 * allocations necessary to record that reservation occur outside the
3753 * spinlock. For private mappings, we also lookup the pagecache
3754 * page now as it is used to determine if a reservation has been
3757 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3758 if (vma_needs_reservation(h, vma, address) < 0) {
3762 /* Just decrements count, does not deallocate */
3763 vma_end_reservation(h, vma, address);
3765 if (!(vma->vm_flags & VM_MAYSHARE))
3766 pagecache_page = hugetlbfs_pagecache_page(h,
3770 ptl = huge_pte_lock(h, mm, ptep);
3772 /* Check for a racing update before calling hugetlb_cow */
3773 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3777 * hugetlb_cow() requires page locks of pte_page(entry) and
3778 * pagecache_page, so here we need take the former one
3779 * when page != pagecache_page or !pagecache_page.
3781 page = pte_page(entry);
3782 if (page != pagecache_page)
3783 if (!trylock_page(page)) {
3790 if (flags & FAULT_FLAG_WRITE) {
3791 if (!huge_pte_write(entry)) {
3792 ret = hugetlb_cow(mm, vma, address, ptep, entry,
3793 pagecache_page, ptl);
3796 entry = huge_pte_mkdirty(entry);
3798 entry = pte_mkyoung(entry);
3799 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3800 flags & FAULT_FLAG_WRITE))
3801 update_mmu_cache(vma, address, ptep);
3803 if (page != pagecache_page)
3809 if (pagecache_page) {
3810 unlock_page(pagecache_page);
3811 put_page(pagecache_page);
3814 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3816 * Generally it's safe to hold refcount during waiting page lock. But
3817 * here we just wait to defer the next page fault to avoid busy loop and
3818 * the page is not used after unlocked before returning from the current
3819 * page fault. So we are safe from accessing freed page, even if we wait
3820 * here without taking refcount.
3823 wait_on_page_locked(page);
3827 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3828 struct page **pages, struct vm_area_struct **vmas,
3829 unsigned long *position, unsigned long *nr_pages,
3830 long i, unsigned int flags)
3832 unsigned long pfn_offset;
3833 unsigned long vaddr = *position;
3834 unsigned long remainder = *nr_pages;
3835 struct hstate *h = hstate_vma(vma);
3837 while (vaddr < vma->vm_end && remainder) {
3839 spinlock_t *ptl = NULL;
3844 * If we have a pending SIGKILL, don't keep faulting pages and
3845 * potentially allocating memory.
3847 if (unlikely(fatal_signal_pending(current))) {
3853 * Some archs (sparc64, sh*) have multiple pte_ts to
3854 * each hugepage. We have to make sure we get the
3855 * first, for the page indexing below to work.
3857 * Note that page table lock is not held when pte is null.
3859 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3861 ptl = huge_pte_lock(h, mm, pte);
3862 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3865 * When coredumping, it suits get_dump_page if we just return
3866 * an error where there's an empty slot with no huge pagecache
3867 * to back it. This way, we avoid allocating a hugepage, and
3868 * the sparse dumpfile avoids allocating disk blocks, but its
3869 * huge holes still show up with zeroes where they need to be.
3871 if (absent && (flags & FOLL_DUMP) &&
3872 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3880 * We need call hugetlb_fault for both hugepages under migration
3881 * (in which case hugetlb_fault waits for the migration,) and
3882 * hwpoisoned hugepages (in which case we need to prevent the
3883 * caller from accessing to them.) In order to do this, we use
3884 * here is_swap_pte instead of is_hugetlb_entry_migration and
3885 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3886 * both cases, and because we can't follow correct pages
3887 * directly from any kind of swap entries.
3889 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3890 ((flags & FOLL_WRITE) &&
3891 !huge_pte_write(huge_ptep_get(pte)))) {
3896 ret = hugetlb_fault(mm, vma, vaddr,
3897 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3898 if (!(ret & VM_FAULT_ERROR))
3905 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3906 page = pte_page(huge_ptep_get(pte));
3909 pages[i] = mem_map_offset(page, pfn_offset);
3910 get_page_foll(pages[i]);
3920 if (vaddr < vma->vm_end && remainder &&
3921 pfn_offset < pages_per_huge_page(h)) {
3923 * We use pfn_offset to avoid touching the pageframes
3924 * of this compound page.
3930 *nr_pages = remainder;
3933 return i ? i : -EFAULT;
3936 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3937 unsigned long address, unsigned long end, pgprot_t newprot)
3939 struct mm_struct *mm = vma->vm_mm;
3940 unsigned long start = address;
3943 struct hstate *h = hstate_vma(vma);
3944 unsigned long pages = 0;
3946 BUG_ON(address >= end);
3947 flush_cache_range(vma, address, end);
3949 mmu_notifier_invalidate_range_start(mm, start, end);
3950 i_mmap_lock_write(vma->vm_file->f_mapping);
3951 for (; address < end; address += huge_page_size(h)) {
3953 ptep = huge_pte_offset(mm, address);
3956 ptl = huge_pte_lock(h, mm, ptep);
3957 if (huge_pmd_unshare(mm, &address, ptep)) {
3962 pte = huge_ptep_get(ptep);
3963 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
3967 if (unlikely(is_hugetlb_entry_migration(pte))) {
3968 swp_entry_t entry = pte_to_swp_entry(pte);
3970 if (is_write_migration_entry(entry)) {
3973 make_migration_entry_read(&entry);
3974 newpte = swp_entry_to_pte(entry);
3975 set_huge_pte_at(mm, address, ptep, newpte);
3981 if (!huge_pte_none(pte)) {
3982 pte = huge_ptep_get_and_clear(mm, address, ptep);
3983 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3984 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3985 set_huge_pte_at(mm, address, ptep, pte);
3991 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
3992 * may have cleared our pud entry and done put_page on the page table:
3993 * once we release i_mmap_rwsem, another task can do the final put_page
3994 * and that page table be reused and filled with junk.
3996 flush_tlb_range(vma, start, end);
3997 mmu_notifier_invalidate_range(mm, start, end);
3998 i_mmap_unlock_write(vma->vm_file->f_mapping);
3999 mmu_notifier_invalidate_range_end(mm, start, end);
4001 return pages << h->order;
4004 int hugetlb_reserve_pages(struct inode *inode,
4006 struct vm_area_struct *vma,
4007 vm_flags_t vm_flags)
4010 struct hstate *h = hstate_inode(inode);
4011 struct hugepage_subpool *spool = subpool_inode(inode);
4012 struct resv_map *resv_map;
4016 * Only apply hugepage reservation if asked. At fault time, an
4017 * attempt will be made for VM_NORESERVE to allocate a page
4018 * without using reserves
4020 if (vm_flags & VM_NORESERVE)
4024 * Shared mappings base their reservation on the number of pages that
4025 * are already allocated on behalf of the file. Private mappings need
4026 * to reserve the full area even if read-only as mprotect() may be
4027 * called to make the mapping read-write. Assume !vma is a shm mapping
4029 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4030 resv_map = inode_resv_map(inode);
4032 chg = region_chg(resv_map, from, to);
4035 resv_map = resv_map_alloc();
4041 set_vma_resv_map(vma, resv_map);
4042 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
4051 * There must be enough pages in the subpool for the mapping. If
4052 * the subpool has a minimum size, there may be some global
4053 * reservations already in place (gbl_reserve).
4055 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
4056 if (gbl_reserve < 0) {
4062 * Check enough hugepages are available for the reservation.
4063 * Hand the pages back to the subpool if there are not
4065 ret = hugetlb_acct_memory(h, gbl_reserve);
4067 /* put back original number of pages, chg */
4068 (void)hugepage_subpool_put_pages(spool, chg);
4073 * Account for the reservations made. Shared mappings record regions
4074 * that have reservations as they are shared by multiple VMAs.
4075 * When the last VMA disappears, the region map says how much
4076 * the reservation was and the page cache tells how much of
4077 * the reservation was consumed. Private mappings are per-VMA and
4078 * only the consumed reservations are tracked. When the VMA
4079 * disappears, the original reservation is the VMA size and the
4080 * consumed reservations are stored in the map. Hence, nothing
4081 * else has to be done for private mappings here
4083 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4084 long add = region_add(resv_map, from, to);
4086 if (unlikely(chg > add)) {
4088 * pages in this range were added to the reserve
4089 * map between region_chg and region_add. This
4090 * indicates a race with alloc_huge_page. Adjust
4091 * the subpool and reserve counts modified above
4092 * based on the difference.
4096 rsv_adjust = hugepage_subpool_put_pages(spool,
4098 hugetlb_acct_memory(h, -rsv_adjust);
4103 if (!vma || vma->vm_flags & VM_MAYSHARE)
4104 region_abort(resv_map, from, to);
4105 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4106 kref_put(&resv_map->refs, resv_map_release);
4110 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
4113 struct hstate *h = hstate_inode(inode);
4114 struct resv_map *resv_map = inode_resv_map(inode);
4116 struct hugepage_subpool *spool = subpool_inode(inode);
4120 chg = region_del(resv_map, start, end);
4122 * region_del() can fail in the rare case where a region
4123 * must be split and another region descriptor can not be
4124 * allocated. If end == LONG_MAX, it will not fail.
4130 spin_lock(&inode->i_lock);
4131 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
4132 spin_unlock(&inode->i_lock);
4135 * If the subpool has a minimum size, the number of global
4136 * reservations to be released may be adjusted.
4138 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
4139 hugetlb_acct_memory(h, -gbl_reserve);
4144 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4145 static unsigned long page_table_shareable(struct vm_area_struct *svma,
4146 struct vm_area_struct *vma,
4147 unsigned long addr, pgoff_t idx)
4149 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
4151 unsigned long sbase = saddr & PUD_MASK;
4152 unsigned long s_end = sbase + PUD_SIZE;
4154 /* Allow segments to share if only one is marked locked */
4155 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
4156 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4159 * match the virtual addresses, permission and the alignment of the
4162 if (pmd_index(addr) != pmd_index(saddr) ||
4163 vm_flags != svm_flags ||
4164 sbase < svma->vm_start || svma->vm_end < s_end)
4170 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4172 unsigned long base = addr & PUD_MASK;
4173 unsigned long end = base + PUD_SIZE;
4176 * check on proper vm_flags and page table alignment
4178 if (vma->vm_flags & VM_MAYSHARE &&
4179 vma->vm_start <= base && end <= vma->vm_end)
4185 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4186 * and returns the corresponding pte. While this is not necessary for the
4187 * !shared pmd case because we can allocate the pmd later as well, it makes the
4188 * code much cleaner. pmd allocation is essential for the shared case because
4189 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4190 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4191 * bad pmd for sharing.
4193 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4195 struct vm_area_struct *vma = find_vma(mm, addr);
4196 struct address_space *mapping = vma->vm_file->f_mapping;
4197 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
4199 struct vm_area_struct *svma;
4200 unsigned long saddr;
4205 if (!vma_shareable(vma, addr))
4206 return (pte_t *)pmd_alloc(mm, pud, addr);
4208 i_mmap_lock_write(mapping);
4209 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
4213 saddr = page_table_shareable(svma, vma, addr, idx);
4215 spte = huge_pte_offset(svma->vm_mm, saddr);
4217 get_page(virt_to_page(spte));
4226 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
4228 if (pud_none(*pud)) {
4229 pud_populate(mm, pud,
4230 (pmd_t *)((unsigned long)spte & PAGE_MASK));
4233 put_page(virt_to_page(spte));
4237 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4238 i_mmap_unlock_write(mapping);
4243 * unmap huge page backed by shared pte.
4245 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4246 * indicated by page_count > 1, unmap is achieved by clearing pud and
4247 * decrementing the ref count. If count == 1, the pte page is not shared.
4249 * called with page table lock held.
4251 * returns: 1 successfully unmapped a shared pte page
4252 * 0 the underlying pte page is not shared, or it is the last user
4254 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4256 pgd_t *pgd = pgd_offset(mm, *addr);
4257 pud_t *pud = pud_offset(pgd, *addr);
4259 BUG_ON(page_count(virt_to_page(ptep)) == 0);
4260 if (page_count(virt_to_page(ptep)) == 1)
4264 put_page(virt_to_page(ptep));
4266 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
4269 #define want_pmd_share() (1)
4270 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4271 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4276 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4280 #define want_pmd_share() (0)
4281 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4283 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4284 pte_t *huge_pte_alloc(struct mm_struct *mm,
4285 unsigned long addr, unsigned long sz)
4291 pgd = pgd_offset(mm, addr);
4292 pud = pud_alloc(mm, pgd, addr);
4294 if (sz == PUD_SIZE) {
4297 BUG_ON(sz != PMD_SIZE);
4298 if (want_pmd_share() && pud_none(*pud))
4299 pte = huge_pmd_share(mm, addr, pud);
4301 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4304 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
4309 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
4315 pgd = pgd_offset(mm, addr);
4316 if (pgd_present(*pgd)) {
4317 pud = pud_offset(pgd, addr);
4318 if (pud_present(*pud)) {
4320 return (pte_t *)pud;
4321 pmd = pmd_offset(pud, addr);
4324 return (pte_t *) pmd;
4327 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4330 * These functions are overwritable if your architecture needs its own
4333 struct page * __weak
4334 follow_huge_addr(struct mm_struct *mm, unsigned long address,
4337 return ERR_PTR(-EINVAL);
4340 struct page * __weak
4341 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4342 pmd_t *pmd, int flags)
4344 struct page *page = NULL;
4347 ptl = pmd_lockptr(mm, pmd);
4350 * make sure that the address range covered by this pmd is not
4351 * unmapped from other threads.
4353 if (!pmd_huge(*pmd))
4355 if (pmd_present(*pmd)) {
4356 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4357 if (flags & FOLL_GET)
4360 if (is_hugetlb_entry_migration(huge_ptep_get((pte_t *)pmd))) {
4362 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
4366 * hwpoisoned entry is treated as no_page_table in
4367 * follow_page_mask().
4375 struct page * __weak
4376 follow_huge_pud(struct mm_struct *mm, unsigned long address,
4377 pud_t *pud, int flags)
4379 if (flags & FOLL_GET)
4382 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4385 #ifdef CONFIG_MEMORY_FAILURE
4388 * This function is called from memory failure code.
4389 * Assume the caller holds page lock of the head page.
4391 int dequeue_hwpoisoned_huge_page(struct page *hpage)
4393 struct hstate *h = page_hstate(hpage);
4394 int nid = page_to_nid(hpage);
4397 spin_lock(&hugetlb_lock);
4399 * Just checking !page_huge_active is not enough, because that could be
4400 * an isolated/hwpoisoned hugepage (which have >0 refcount).
4402 if (!page_huge_active(hpage) && !page_count(hpage)) {
4404 * Hwpoisoned hugepage isn't linked to activelist or freelist,
4405 * but dangling hpage->lru can trigger list-debug warnings
4406 * (this happens when we call unpoison_memory() on it),
4407 * so let it point to itself with list_del_init().
4409 list_del_init(&hpage->lru);
4410 set_page_refcounted(hpage);
4411 h->free_huge_pages--;
4412 h->free_huge_pages_node[nid]--;
4415 spin_unlock(&hugetlb_lock);
4420 bool isolate_huge_page(struct page *page, struct list_head *list)
4424 VM_BUG_ON_PAGE(!PageHead(page), page);
4425 spin_lock(&hugetlb_lock);
4426 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
4430 clear_page_huge_active(page);
4431 list_move_tail(&page->lru, list);
4433 spin_unlock(&hugetlb_lock);
4437 void putback_active_hugepage(struct page *page)
4439 VM_BUG_ON_PAGE(!PageHead(page), page);
4440 spin_lock(&hugetlb_lock);
4441 set_page_huge_active(page);
4442 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
4443 spin_unlock(&hugetlb_lock);