2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
5 #include <linux/list.h>
6 #include <linux/init.h>
8 #include <linux/seq_file.h>
9 #include <linux/sysctl.h>
10 #include <linux/highmem.h>
11 #include <linux/mmu_notifier.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/compiler.h>
16 #include <linux/cpuset.h>
17 #include <linux/mutex.h>
18 #include <linux/bootmem.h>
19 #include <linux/sysfs.h>
20 #include <linux/slab.h>
21 #include <linux/sched/signal.h>
22 #include <linux/rmap.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/jhash.h>
28 #include <asm/pgtable.h>
32 #include <linux/hugetlb.h>
33 #include <linux/hugetlb_cgroup.h>
34 #include <linux/node.h>
35 #include <linux/userfaultfd_k.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;
55 static bool __initdata parsed_valid_hugepagesz = true;
58 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
59 * free_huge_pages, and surplus_huge_pages.
61 DEFINE_SPINLOCK(hugetlb_lock);
64 * Serializes faults on the same logical page. This is used to
65 * prevent spurious OOMs when the hugepage pool is fully utilized.
67 static int num_fault_mutexes;
68 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
70 /* Forward declaration */
71 static int hugetlb_acct_memory(struct hstate *h, long delta);
73 static char * __init memfmt(char *buf, unsigned long n)
76 sprintf(buf, "%lu GB", n >> 30);
77 else if (n >= (1UL << 20))
78 sprintf(buf, "%lu MB", n >> 20);
80 sprintf(buf, "%lu KB", n >> 10);
84 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
86 bool free = (spool->count == 0) && (spool->used_hpages == 0);
88 spin_unlock(&spool->lock);
90 /* If no pages are used, and no other handles to the subpool
91 * remain, give up any reservations mased on minimum size and
94 if (spool->min_hpages != -1)
95 hugetlb_acct_memory(spool->hstate,
101 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
104 struct hugepage_subpool *spool;
106 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
110 spin_lock_init(&spool->lock);
112 spool->max_hpages = max_hpages;
114 spool->min_hpages = min_hpages;
116 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
120 spool->rsv_hpages = min_hpages;
125 void hugepage_put_subpool(struct hugepage_subpool *spool)
127 spin_lock(&spool->lock);
128 BUG_ON(!spool->count);
130 unlock_or_release_subpool(spool);
134 * Subpool accounting for allocating and reserving pages.
135 * Return -ENOMEM if there are not enough resources to satisfy the
136 * the request. Otherwise, return the number of pages by which the
137 * global pools must be adjusted (upward). The returned value may
138 * only be different than the passed value (delta) in the case where
139 * a subpool minimum size must be manitained.
141 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
149 spin_lock(&spool->lock);
151 if (spool->max_hpages != -1) { /* maximum size accounting */
152 if ((spool->used_hpages + delta) <= spool->max_hpages)
153 spool->used_hpages += delta;
160 /* minimum size accounting */
161 if (spool->min_hpages != -1 && spool->rsv_hpages) {
162 if (delta > spool->rsv_hpages) {
164 * Asking for more reserves than those already taken on
165 * behalf of subpool. Return difference.
167 ret = delta - spool->rsv_hpages;
168 spool->rsv_hpages = 0;
170 ret = 0; /* reserves already accounted for */
171 spool->rsv_hpages -= delta;
176 spin_unlock(&spool->lock);
181 * Subpool accounting for freeing and unreserving pages.
182 * Return the number of global page reservations that must be dropped.
183 * The return value may only be different than the passed value (delta)
184 * in the case where a subpool minimum size must be maintained.
186 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
194 spin_lock(&spool->lock);
196 if (spool->max_hpages != -1) /* maximum size accounting */
197 spool->used_hpages -= delta;
199 /* minimum size accounting */
200 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
201 if (spool->rsv_hpages + delta <= spool->min_hpages)
204 ret = spool->rsv_hpages + delta - spool->min_hpages;
206 spool->rsv_hpages += delta;
207 if (spool->rsv_hpages > spool->min_hpages)
208 spool->rsv_hpages = spool->min_hpages;
212 * If hugetlbfs_put_super couldn't free spool due to an outstanding
213 * quota reference, free it now.
215 unlock_or_release_subpool(spool);
220 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
222 return HUGETLBFS_SB(inode->i_sb)->spool;
225 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
227 return subpool_inode(file_inode(vma->vm_file));
231 * Region tracking -- allows tracking of reservations and instantiated pages
232 * across the pages in a mapping.
234 * The region data structures are embedded into a resv_map and protected
235 * by a resv_map's lock. The set of regions within the resv_map represent
236 * reservations for huge pages, or huge pages that have already been
237 * instantiated within the map. The from and to elements are huge page
238 * indicies into the associated mapping. from indicates the starting index
239 * of the region. to represents the first index past the end of the region.
241 * For example, a file region structure with from == 0 and to == 4 represents
242 * four huge pages in a mapping. It is important to note that the to element
243 * represents the first element past the end of the region. This is used in
244 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
246 * Interval notation of the form [from, to) will be used to indicate that
247 * the endpoint from is inclusive and to is exclusive.
250 struct list_head link;
256 * Add the huge page range represented by [f, t) to the reserve
257 * map. In the normal case, existing regions will be expanded
258 * to accommodate the specified range. Sufficient regions should
259 * exist for expansion due to the previous call to region_chg
260 * with the same range. However, it is possible that region_del
261 * could have been called after region_chg and modifed the map
262 * in such a way that no region exists to be expanded. In this
263 * case, pull a region descriptor from the cache associated with
264 * the map and use that for the new range.
266 * Return the number of new huge pages added to the map. This
267 * number is greater than or equal to zero.
269 static long region_add(struct resv_map *resv, long f, long t)
271 struct list_head *head = &resv->regions;
272 struct file_region *rg, *nrg, *trg;
275 spin_lock(&resv->lock);
276 /* Locate the region we are either in or before. */
277 list_for_each_entry(rg, head, link)
282 * If no region exists which can be expanded to include the
283 * specified range, the list must have been modified by an
284 * interleving call to region_del(). Pull a region descriptor
285 * from the cache and use it for this range.
287 if (&rg->link == head || t < rg->from) {
288 VM_BUG_ON(resv->region_cache_count <= 0);
290 resv->region_cache_count--;
291 nrg = list_first_entry(&resv->region_cache, struct file_region,
293 list_del(&nrg->link);
297 list_add(&nrg->link, rg->link.prev);
303 /* Round our left edge to the current segment if it encloses us. */
307 /* Check for and consume any regions we now overlap with. */
309 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
310 if (&rg->link == head)
315 /* If this area reaches higher then extend our area to
316 * include it completely. If this is not the first area
317 * which we intend to reuse, free it. */
321 /* Decrement return value by the deleted range.
322 * Another range will span this area so that by
323 * end of routine add will be >= zero
325 add -= (rg->to - rg->from);
331 add += (nrg->from - f); /* Added to beginning of region */
333 add += t - nrg->to; /* Added to end of region */
337 resv->adds_in_progress--;
338 spin_unlock(&resv->lock);
344 * Examine the existing reserve map and determine how many
345 * huge pages in the specified range [f, t) are NOT currently
346 * represented. This routine is called before a subsequent
347 * call to region_add that will actually modify the reserve
348 * map to add the specified range [f, t). region_chg does
349 * not change the number of huge pages represented by the
350 * map. However, if the existing regions in the map can not
351 * be expanded to represent the new range, a new file_region
352 * structure is added to the map as a placeholder. This is
353 * so that the subsequent region_add call will have all the
354 * regions it needs and will not fail.
356 * Upon entry, region_chg will also examine the cache of region descriptors
357 * associated with the map. If there are not enough descriptors cached, one
358 * will be allocated for the in progress add operation.
360 * Returns the number of huge pages that need to be added to the existing
361 * reservation map for the range [f, t). This number is greater or equal to
362 * zero. -ENOMEM is returned if a new file_region structure or cache entry
363 * is needed and can not be allocated.
365 static long region_chg(struct resv_map *resv, long f, long t)
367 struct list_head *head = &resv->regions;
368 struct file_region *rg, *nrg = NULL;
372 spin_lock(&resv->lock);
374 resv->adds_in_progress++;
377 * Check for sufficient descriptors in the cache to accommodate
378 * the number of in progress add operations.
380 if (resv->adds_in_progress > resv->region_cache_count) {
381 struct file_region *trg;
383 VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1);
384 /* Must drop lock to allocate a new descriptor. */
385 resv->adds_in_progress--;
386 spin_unlock(&resv->lock);
388 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
394 spin_lock(&resv->lock);
395 list_add(&trg->link, &resv->region_cache);
396 resv->region_cache_count++;
400 /* Locate the region we are before or in. */
401 list_for_each_entry(rg, head, link)
405 /* If we are below the current region then a new region is required.
406 * Subtle, allocate a new region at the position but make it zero
407 * size such that we can guarantee to record the reservation. */
408 if (&rg->link == head || t < rg->from) {
410 resv->adds_in_progress--;
411 spin_unlock(&resv->lock);
412 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
418 INIT_LIST_HEAD(&nrg->link);
422 list_add(&nrg->link, rg->link.prev);
427 /* Round our left edge to the current segment if it encloses us. */
432 /* Check for and consume any regions we now overlap with. */
433 list_for_each_entry(rg, rg->link.prev, link) {
434 if (&rg->link == head)
439 /* We overlap with this area, if it extends further than
440 * us then we must extend ourselves. Account for its
441 * existing reservation. */
446 chg -= rg->to - rg->from;
450 spin_unlock(&resv->lock);
451 /* We already know we raced and no longer need the new region */
455 spin_unlock(&resv->lock);
460 * Abort the in progress add operation. The adds_in_progress field
461 * of the resv_map keeps track of the operations in progress between
462 * calls to region_chg and region_add. Operations are sometimes
463 * aborted after the call to region_chg. In such cases, region_abort
464 * is called to decrement the adds_in_progress counter.
466 * NOTE: The range arguments [f, t) are not needed or used in this
467 * routine. They are kept to make reading the calling code easier as
468 * arguments will match the associated region_chg call.
470 static void region_abort(struct resv_map *resv, long f, long t)
472 spin_lock(&resv->lock);
473 VM_BUG_ON(!resv->region_cache_count);
474 resv->adds_in_progress--;
475 spin_unlock(&resv->lock);
479 * Delete the specified range [f, t) from the reserve map. If the
480 * t parameter is LONG_MAX, this indicates that ALL regions after f
481 * should be deleted. Locate the regions which intersect [f, t)
482 * and either trim, delete or split the existing regions.
484 * Returns the number of huge pages deleted from the reserve map.
485 * In the normal case, the return value is zero or more. In the
486 * case where a region must be split, a new region descriptor must
487 * be allocated. If the allocation fails, -ENOMEM will be returned.
488 * NOTE: If the parameter t == LONG_MAX, then we will never split
489 * a region and possibly return -ENOMEM. Callers specifying
490 * t == LONG_MAX do not need to check for -ENOMEM error.
492 static long region_del(struct resv_map *resv, long f, long t)
494 struct list_head *head = &resv->regions;
495 struct file_region *rg, *trg;
496 struct file_region *nrg = NULL;
500 spin_lock(&resv->lock);
501 list_for_each_entry_safe(rg, trg, head, link) {
503 * Skip regions before the range to be deleted. file_region
504 * ranges are normally of the form [from, to). However, there
505 * may be a "placeholder" entry in the map which is of the form
506 * (from, to) with from == to. Check for placeholder entries
507 * at the beginning of the range to be deleted.
509 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
515 if (f > rg->from && t < rg->to) { /* Must split region */
517 * Check for an entry in the cache before dropping
518 * lock and attempting allocation.
521 resv->region_cache_count > resv->adds_in_progress) {
522 nrg = list_first_entry(&resv->region_cache,
525 list_del(&nrg->link);
526 resv->region_cache_count--;
530 spin_unlock(&resv->lock);
531 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
539 /* New entry for end of split region */
542 INIT_LIST_HEAD(&nrg->link);
544 /* Original entry is trimmed */
547 list_add(&nrg->link, &rg->link);
552 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
553 del += rg->to - rg->from;
559 if (f <= rg->from) { /* Trim beginning of region */
562 } else { /* Trim end of region */
568 spin_unlock(&resv->lock);
574 * A rare out of memory error was encountered which prevented removal of
575 * the reserve map region for a page. The huge page itself was free'ed
576 * and removed from the page cache. This routine will adjust the subpool
577 * usage count, and the global reserve count if needed. By incrementing
578 * these counts, the reserve map entry which could not be deleted will
579 * appear as a "reserved" entry instead of simply dangling with incorrect
582 void hugetlb_fix_reserve_counts(struct inode *inode)
584 struct hugepage_subpool *spool = subpool_inode(inode);
587 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
589 struct hstate *h = hstate_inode(inode);
591 hugetlb_acct_memory(h, 1);
596 * Count and return the number of huge pages in the reserve map
597 * that intersect with the range [f, t).
599 static long region_count(struct resv_map *resv, long f, long t)
601 struct list_head *head = &resv->regions;
602 struct file_region *rg;
605 spin_lock(&resv->lock);
606 /* Locate each segment we overlap with, and count that overlap. */
607 list_for_each_entry(rg, head, link) {
616 seg_from = max(rg->from, f);
617 seg_to = min(rg->to, t);
619 chg += seg_to - seg_from;
621 spin_unlock(&resv->lock);
627 * Convert the address within this vma to the page offset within
628 * the mapping, in pagecache page units; huge pages here.
630 static pgoff_t vma_hugecache_offset(struct hstate *h,
631 struct vm_area_struct *vma, unsigned long address)
633 return ((address - vma->vm_start) >> huge_page_shift(h)) +
634 (vma->vm_pgoff >> huge_page_order(h));
637 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
638 unsigned long address)
640 return vma_hugecache_offset(hstate_vma(vma), vma, address);
642 EXPORT_SYMBOL_GPL(linear_hugepage_index);
645 * Return the size of the pages allocated when backing a VMA. In the majority
646 * cases this will be same size as used by the page table entries.
648 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
650 struct hstate *hstate;
652 if (!is_vm_hugetlb_page(vma))
655 hstate = hstate_vma(vma);
657 return 1UL << huge_page_shift(hstate);
659 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
662 * Return the page size being used by the MMU to back a VMA. In the majority
663 * of cases, the page size used by the kernel matches the MMU size. On
664 * architectures where it differs, an architecture-specific version of this
665 * function is required.
667 #ifndef vma_mmu_pagesize
668 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
670 return vma_kernel_pagesize(vma);
675 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
676 * bits of the reservation map pointer, which are always clear due to
679 #define HPAGE_RESV_OWNER (1UL << 0)
680 #define HPAGE_RESV_UNMAPPED (1UL << 1)
681 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
684 * These helpers are used to track how many pages are reserved for
685 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
686 * is guaranteed to have their future faults succeed.
688 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
689 * the reserve counters are updated with the hugetlb_lock held. It is safe
690 * to reset the VMA at fork() time as it is not in use yet and there is no
691 * chance of the global counters getting corrupted as a result of the values.
693 * The private mapping reservation is represented in a subtly different
694 * manner to a shared mapping. A shared mapping has a region map associated
695 * with the underlying file, this region map represents the backing file
696 * pages which have ever had a reservation assigned which this persists even
697 * after the page is instantiated. A private mapping has a region map
698 * associated with the original mmap which is attached to all VMAs which
699 * reference it, this region map represents those offsets which have consumed
700 * reservation ie. where pages have been instantiated.
702 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
704 return (unsigned long)vma->vm_private_data;
707 static void set_vma_private_data(struct vm_area_struct *vma,
710 vma->vm_private_data = (void *)value;
713 struct resv_map *resv_map_alloc(void)
715 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
716 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
718 if (!resv_map || !rg) {
724 kref_init(&resv_map->refs);
725 spin_lock_init(&resv_map->lock);
726 INIT_LIST_HEAD(&resv_map->regions);
728 resv_map->adds_in_progress = 0;
730 INIT_LIST_HEAD(&resv_map->region_cache);
731 list_add(&rg->link, &resv_map->region_cache);
732 resv_map->region_cache_count = 1;
737 void resv_map_release(struct kref *ref)
739 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
740 struct list_head *head = &resv_map->region_cache;
741 struct file_region *rg, *trg;
743 /* Clear out any active regions before we release the map. */
744 region_del(resv_map, 0, LONG_MAX);
746 /* ... and any entries left in the cache */
747 list_for_each_entry_safe(rg, trg, head, link) {
752 VM_BUG_ON(resv_map->adds_in_progress);
757 static inline struct resv_map *inode_resv_map(struct inode *inode)
759 return inode->i_mapping->private_data;
762 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
764 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
765 if (vma->vm_flags & VM_MAYSHARE) {
766 struct address_space *mapping = vma->vm_file->f_mapping;
767 struct inode *inode = mapping->host;
769 return inode_resv_map(inode);
772 return (struct resv_map *)(get_vma_private_data(vma) &
777 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
779 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
780 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
782 set_vma_private_data(vma, (get_vma_private_data(vma) &
783 HPAGE_RESV_MASK) | (unsigned long)map);
786 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
788 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
789 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
791 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
794 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
796 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
798 return (get_vma_private_data(vma) & flag) != 0;
801 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
802 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
804 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
805 if (!(vma->vm_flags & VM_MAYSHARE))
806 vma->vm_private_data = (void *)0;
809 /* Returns true if the VMA has associated reserve pages */
810 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
812 if (vma->vm_flags & VM_NORESERVE) {
814 * This address is already reserved by other process(chg == 0),
815 * so, we should decrement reserved count. Without decrementing,
816 * reserve count remains after releasing inode, because this
817 * allocated page will go into page cache and is regarded as
818 * coming from reserved pool in releasing step. Currently, we
819 * don't have any other solution to deal with this situation
820 * properly, so add work-around here.
822 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
828 /* Shared mappings always use reserves */
829 if (vma->vm_flags & VM_MAYSHARE) {
831 * We know VM_NORESERVE is not set. Therefore, there SHOULD
832 * be a region map for all pages. The only situation where
833 * there is no region map is if a hole was punched via
834 * fallocate. In this case, there really are no reverves to
835 * use. This situation is indicated if chg != 0.
844 * Only the process that called mmap() has reserves for
847 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
849 * Like the shared case above, a hole punch or truncate
850 * could have been performed on the private mapping.
851 * Examine the value of chg to determine if reserves
852 * actually exist or were previously consumed.
853 * Very Subtle - The value of chg comes from a previous
854 * call to vma_needs_reserves(). The reserve map for
855 * private mappings has different (opposite) semantics
856 * than that of shared mappings. vma_needs_reserves()
857 * has already taken this difference in semantics into
858 * account. Therefore, the meaning of chg is the same
859 * as in the shared case above. Code could easily be
860 * combined, but keeping it separate draws attention to
861 * subtle differences.
872 static void enqueue_huge_page(struct hstate *h, struct page *page)
874 int nid = page_to_nid(page);
875 list_move(&page->lru, &h->hugepage_freelists[nid]);
876 h->free_huge_pages++;
877 h->free_huge_pages_node[nid]++;
880 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
884 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
885 if (!PageHWPoison(page))
888 * if 'non-isolated free hugepage' not found on the list,
889 * the allocation fails.
891 if (&h->hugepage_freelists[nid] == &page->lru)
893 list_move(&page->lru, &h->hugepage_activelist);
894 set_page_refcounted(page);
895 h->free_huge_pages--;
896 h->free_huge_pages_node[nid]--;
900 static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
905 if (nid != NUMA_NO_NODE)
906 return dequeue_huge_page_node_exact(h, nid);
908 for_each_online_node(node) {
909 page = dequeue_huge_page_node_exact(h, node);
916 /* Movability of hugepages depends on migration support. */
917 static inline gfp_t htlb_alloc_mask(struct hstate *h)
919 if (hugepages_treat_as_movable || hugepage_migration_supported(h))
920 return GFP_HIGHUSER_MOVABLE;
925 static struct page *dequeue_huge_page_vma(struct hstate *h,
926 struct vm_area_struct *vma,
927 unsigned long address, int avoid_reserve,
930 struct page *page = NULL;
931 struct mempolicy *mpol;
932 nodemask_t *nodemask;
935 struct zonelist *zonelist;
938 unsigned int cpuset_mems_cookie;
941 * A child process with MAP_PRIVATE mappings created by their parent
942 * have no page reserves. This check ensures that reservations are
943 * not "stolen". The child may still get SIGKILLed
945 if (!vma_has_reserves(vma, chg) &&
946 h->free_huge_pages - h->resv_huge_pages == 0)
949 /* If reserves cannot be used, ensure enough pages are in the pool */
950 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
954 cpuset_mems_cookie = read_mems_allowed_begin();
955 gfp_mask = htlb_alloc_mask(h);
956 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
957 zonelist = node_zonelist(nid, gfp_mask);
959 for_each_zone_zonelist_nodemask(zone, z, zonelist,
960 MAX_NR_ZONES - 1, nodemask) {
961 if (cpuset_zone_allowed(zone, gfp_mask)) {
962 page = dequeue_huge_page_node(h, zone_to_nid(zone));
966 if (!vma_has_reserves(vma, chg))
969 SetPagePrivate(page);
970 h->resv_huge_pages--;
977 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
986 * common helper functions for hstate_next_node_to_{alloc|free}.
987 * We may have allocated or freed a huge page based on a different
988 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
989 * be outside of *nodes_allowed. Ensure that we use an allowed
990 * node for alloc or free.
992 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
994 nid = next_node_in(nid, *nodes_allowed);
995 VM_BUG_ON(nid >= MAX_NUMNODES);
1000 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1002 if (!node_isset(nid, *nodes_allowed))
1003 nid = next_node_allowed(nid, nodes_allowed);
1008 * returns the previously saved node ["this node"] from which to
1009 * allocate a persistent huge page for the pool and advance the
1010 * next node from which to allocate, handling wrap at end of node
1013 static int hstate_next_node_to_alloc(struct hstate *h,
1014 nodemask_t *nodes_allowed)
1018 VM_BUG_ON(!nodes_allowed);
1020 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1021 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1027 * helper for free_pool_huge_page() - return the previously saved
1028 * node ["this node"] from which to free a huge page. Advance the
1029 * next node id whether or not we find a free huge page to free so
1030 * that the next attempt to free addresses the next node.
1032 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1036 VM_BUG_ON(!nodes_allowed);
1038 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1039 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1044 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1045 for (nr_nodes = nodes_weight(*mask); \
1047 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1050 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1051 for (nr_nodes = nodes_weight(*mask); \
1053 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1056 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1057 static void destroy_compound_gigantic_page(struct page *page,
1061 int nr_pages = 1 << order;
1062 struct page *p = page + 1;
1064 atomic_set(compound_mapcount_ptr(page), 0);
1065 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1066 clear_compound_head(p);
1067 set_page_refcounted(p);
1070 set_compound_order(page, 0);
1071 __ClearPageHead(page);
1074 static void free_gigantic_page(struct page *page, unsigned int order)
1076 free_contig_range(page_to_pfn(page), 1 << order);
1079 static int __alloc_gigantic_page(unsigned long start_pfn,
1080 unsigned long nr_pages)
1082 unsigned long end_pfn = start_pfn + nr_pages;
1083 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
1087 static bool pfn_range_valid_gigantic(struct zone *z,
1088 unsigned long start_pfn, unsigned long nr_pages)
1090 unsigned long i, end_pfn = start_pfn + nr_pages;
1093 for (i = start_pfn; i < end_pfn; i++) {
1097 page = pfn_to_page(i);
1099 if (page_zone(page) != z)
1102 if (PageReserved(page))
1105 if (page_count(page) > 0)
1115 static bool zone_spans_last_pfn(const struct zone *zone,
1116 unsigned long start_pfn, unsigned long nr_pages)
1118 unsigned long last_pfn = start_pfn + nr_pages - 1;
1119 return zone_spans_pfn(zone, last_pfn);
1122 static struct page *alloc_gigantic_page(int nid, unsigned int order)
1124 unsigned long nr_pages = 1 << order;
1125 unsigned long ret, pfn, flags;
1128 z = NODE_DATA(nid)->node_zones;
1129 for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
1130 spin_lock_irqsave(&z->lock, flags);
1132 pfn = ALIGN(z->zone_start_pfn, nr_pages);
1133 while (zone_spans_last_pfn(z, pfn, nr_pages)) {
1134 if (pfn_range_valid_gigantic(z, pfn, nr_pages)) {
1136 * We release the zone lock here because
1137 * alloc_contig_range() will also lock the zone
1138 * at some point. If there's an allocation
1139 * spinning on this lock, it may win the race
1140 * and cause alloc_contig_range() to fail...
1142 spin_unlock_irqrestore(&z->lock, flags);
1143 ret = __alloc_gigantic_page(pfn, nr_pages);
1145 return pfn_to_page(pfn);
1146 spin_lock_irqsave(&z->lock, flags);
1151 spin_unlock_irqrestore(&z->lock, flags);
1157 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1158 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1160 static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
1164 page = alloc_gigantic_page(nid, huge_page_order(h));
1166 prep_compound_gigantic_page(page, huge_page_order(h));
1167 prep_new_huge_page(h, page, nid);
1173 static int alloc_fresh_gigantic_page(struct hstate *h,
1174 nodemask_t *nodes_allowed)
1176 struct page *page = NULL;
1179 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1180 page = alloc_fresh_gigantic_page_node(h, node);
1188 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1189 static inline bool gigantic_page_supported(void) { return false; }
1190 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1191 static inline void destroy_compound_gigantic_page(struct page *page,
1192 unsigned int order) { }
1193 static inline int alloc_fresh_gigantic_page(struct hstate *h,
1194 nodemask_t *nodes_allowed) { return 0; }
1197 static void update_and_free_page(struct hstate *h, struct page *page)
1201 if (hstate_is_gigantic(h) && !gigantic_page_supported())
1205 h->nr_huge_pages_node[page_to_nid(page)]--;
1206 for (i = 0; i < pages_per_huge_page(h); i++) {
1207 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1208 1 << PG_referenced | 1 << PG_dirty |
1209 1 << PG_active | 1 << PG_private |
1212 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1213 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1214 set_page_refcounted(page);
1215 if (hstate_is_gigantic(h)) {
1216 destroy_compound_gigantic_page(page, huge_page_order(h));
1217 free_gigantic_page(page, huge_page_order(h));
1219 __free_pages(page, huge_page_order(h));
1223 struct hstate *size_to_hstate(unsigned long size)
1227 for_each_hstate(h) {
1228 if (huge_page_size(h) == size)
1235 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1236 * to hstate->hugepage_activelist.)
1238 * This function can be called for tail pages, but never returns true for them.
1240 bool page_huge_active(struct page *page)
1242 VM_BUG_ON_PAGE(!PageHuge(page), page);
1243 return PageHead(page) && PagePrivate(&page[1]);
1246 /* never called for tail page */
1247 static void set_page_huge_active(struct page *page)
1249 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1250 SetPagePrivate(&page[1]);
1253 static void clear_page_huge_active(struct page *page)
1255 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1256 ClearPagePrivate(&page[1]);
1259 void free_huge_page(struct page *page)
1262 * Can't pass hstate in here because it is called from the
1263 * compound page destructor.
1265 struct hstate *h = page_hstate(page);
1266 int nid = page_to_nid(page);
1267 struct hugepage_subpool *spool =
1268 (struct hugepage_subpool *)page_private(page);
1269 bool restore_reserve;
1271 set_page_private(page, 0);
1272 page->mapping = NULL;
1273 VM_BUG_ON_PAGE(page_count(page), page);
1274 VM_BUG_ON_PAGE(page_mapcount(page), page);
1275 restore_reserve = PagePrivate(page);
1276 ClearPagePrivate(page);
1279 * A return code of zero implies that the subpool will be under its
1280 * minimum size if the reservation is not restored after page is free.
1281 * Therefore, force restore_reserve operation.
1283 if (hugepage_subpool_put_pages(spool, 1) == 0)
1284 restore_reserve = true;
1286 spin_lock(&hugetlb_lock);
1287 clear_page_huge_active(page);
1288 hugetlb_cgroup_uncharge_page(hstate_index(h),
1289 pages_per_huge_page(h), page);
1290 if (restore_reserve)
1291 h->resv_huge_pages++;
1293 if (h->surplus_huge_pages_node[nid]) {
1294 /* remove the page from active list */
1295 list_del(&page->lru);
1296 update_and_free_page(h, page);
1297 h->surplus_huge_pages--;
1298 h->surplus_huge_pages_node[nid]--;
1300 arch_clear_hugepage_flags(page);
1301 enqueue_huge_page(h, page);
1303 spin_unlock(&hugetlb_lock);
1306 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1308 INIT_LIST_HEAD(&page->lru);
1309 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1310 spin_lock(&hugetlb_lock);
1311 set_hugetlb_cgroup(page, NULL);
1313 h->nr_huge_pages_node[nid]++;
1314 spin_unlock(&hugetlb_lock);
1315 put_page(page); /* free it into the hugepage allocator */
1318 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1321 int nr_pages = 1 << order;
1322 struct page *p = page + 1;
1324 /* we rely on prep_new_huge_page to set the destructor */
1325 set_compound_order(page, order);
1326 __ClearPageReserved(page);
1327 __SetPageHead(page);
1328 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1330 * For gigantic hugepages allocated through bootmem at
1331 * boot, it's safer to be consistent with the not-gigantic
1332 * hugepages and clear the PG_reserved bit from all tail pages
1333 * too. Otherwse drivers using get_user_pages() to access tail
1334 * pages may get the reference counting wrong if they see
1335 * PG_reserved set on a tail page (despite the head page not
1336 * having PG_reserved set). Enforcing this consistency between
1337 * head and tail pages allows drivers to optimize away a check
1338 * on the head page when they need know if put_page() is needed
1339 * after get_user_pages().
1341 __ClearPageReserved(p);
1342 set_page_count(p, 0);
1343 set_compound_head(p, page);
1345 atomic_set(compound_mapcount_ptr(page), -1);
1349 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1350 * transparent huge pages. See the PageTransHuge() documentation for more
1353 int PageHuge(struct page *page)
1355 if (!PageCompound(page))
1358 page = compound_head(page);
1359 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1361 EXPORT_SYMBOL_GPL(PageHuge);
1364 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1365 * normal or transparent huge pages.
1367 int PageHeadHuge(struct page *page_head)
1369 if (!PageHead(page_head))
1372 return get_compound_page_dtor(page_head) == free_huge_page;
1375 pgoff_t __basepage_index(struct page *page)
1377 struct page *page_head = compound_head(page);
1378 pgoff_t index = page_index(page_head);
1379 unsigned long compound_idx;
1381 if (!PageHuge(page_head))
1382 return page_index(page);
1384 if (compound_order(page_head) >= MAX_ORDER)
1385 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1387 compound_idx = page - page_head;
1389 return (index << compound_order(page_head)) + compound_idx;
1392 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
1396 page = __alloc_pages_node(nid,
1397 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1398 __GFP_REPEAT|__GFP_NOWARN,
1399 huge_page_order(h));
1401 prep_new_huge_page(h, page, nid);
1407 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1413 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1414 page = alloc_fresh_huge_page_node(h, node);
1422 count_vm_event(HTLB_BUDDY_PGALLOC);
1424 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1430 * Free huge page from pool from next node to free.
1431 * Attempt to keep persistent huge pages more or less
1432 * balanced over allowed nodes.
1433 * Called with hugetlb_lock locked.
1435 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1441 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1443 * If we're returning unused surplus pages, only examine
1444 * nodes with surplus pages.
1446 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1447 !list_empty(&h->hugepage_freelists[node])) {
1449 list_entry(h->hugepage_freelists[node].next,
1451 list_del(&page->lru);
1452 h->free_huge_pages--;
1453 h->free_huge_pages_node[node]--;
1455 h->surplus_huge_pages--;
1456 h->surplus_huge_pages_node[node]--;
1458 update_and_free_page(h, page);
1468 * Dissolve a given free hugepage into free buddy pages. This function does
1469 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1470 * number of free hugepages would be reduced below the number of reserved
1473 int dissolve_free_huge_page(struct page *page)
1477 spin_lock(&hugetlb_lock);
1478 if (PageHuge(page) && !page_count(page)) {
1479 struct page *head = compound_head(page);
1480 struct hstate *h = page_hstate(head);
1481 int nid = page_to_nid(head);
1482 if (h->free_huge_pages - h->resv_huge_pages == 0) {
1487 * Move PageHWPoison flag from head page to the raw error page,
1488 * which makes any subpages rather than the error page reusable.
1490 if (PageHWPoison(head) && page != head) {
1491 SetPageHWPoison(page);
1492 ClearPageHWPoison(head);
1494 list_del(&head->lru);
1495 h->free_huge_pages--;
1496 h->free_huge_pages_node[nid]--;
1497 h->max_huge_pages--;
1498 update_and_free_page(h, head);
1501 spin_unlock(&hugetlb_lock);
1506 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1507 * make specified memory blocks removable from the system.
1508 * Note that this will dissolve a free gigantic hugepage completely, if any
1509 * part of it lies within the given range.
1510 * Also note that if dissolve_free_huge_page() returns with an error, all
1511 * free hugepages that were dissolved before that error are lost.
1513 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1519 if (!hugepages_supported())
1522 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1523 page = pfn_to_page(pfn);
1524 if (PageHuge(page) && !page_count(page)) {
1525 rc = dissolve_free_huge_page(page);
1535 * There are 3 ways this can get called:
1536 * 1. With vma+addr: we use the VMA's memory policy
1537 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1538 * page from any node, and let the buddy allocator itself figure
1540 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1541 * strictly from 'nid'
1543 static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
1544 struct vm_area_struct *vma, unsigned long addr, int nid)
1546 int order = huge_page_order(h);
1547 gfp_t gfp = htlb_alloc_mask(h)|__GFP_COMP|__GFP_REPEAT|__GFP_NOWARN;
1548 unsigned int cpuset_mems_cookie;
1551 * We need a VMA to get a memory policy. If we do not
1552 * have one, we use the 'nid' argument.
1554 * The mempolicy stuff below has some non-inlined bits
1555 * and calls ->vm_ops. That makes it hard to optimize at
1556 * compile-time, even when NUMA is off and it does
1557 * nothing. This helps the compiler optimize it out.
1559 if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1561 * If a specific node is requested, make sure to
1562 * get memory from there, but only when a node
1563 * is explicitly specified.
1565 if (nid != NUMA_NO_NODE)
1566 gfp |= __GFP_THISNODE;
1568 * Make sure to call something that can handle
1571 return alloc_pages_node(nid, gfp, order);
1575 * OK, so we have a VMA. Fetch the mempolicy and try to
1576 * allocate a huge page with it. We will only reach this
1577 * when CONFIG_NUMA=y.
1581 struct mempolicy *mpol;
1583 nodemask_t *nodemask;
1585 cpuset_mems_cookie = read_mems_allowed_begin();
1586 nid = huge_node(vma, addr, gfp, &mpol, &nodemask);
1587 mpol_cond_put(mpol);
1588 page = __alloc_pages_nodemask(gfp, order, nid, nodemask);
1591 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1597 * There are two ways to allocate a huge page:
1598 * 1. When you have a VMA and an address (like a fault)
1599 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1601 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1602 * this case which signifies that the allocation should be done with
1603 * respect for the VMA's memory policy.
1605 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1606 * implies that memory policies will not be taken in to account.
1608 static struct page *__alloc_buddy_huge_page(struct hstate *h,
1609 struct vm_area_struct *vma, unsigned long addr, int nid)
1614 if (hstate_is_gigantic(h))
1618 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1619 * This makes sure the caller is picking _one_ of the modes with which
1620 * we can call this function, not both.
1622 if (vma || (addr != -1)) {
1623 VM_WARN_ON_ONCE(addr == -1);
1624 VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1627 * Assume we will successfully allocate the surplus page to
1628 * prevent racing processes from causing the surplus to exceed
1631 * This however introduces a different race, where a process B
1632 * tries to grow the static hugepage pool while alloc_pages() is
1633 * called by process A. B will only examine the per-node
1634 * counters in determining if surplus huge pages can be
1635 * converted to normal huge pages in adjust_pool_surplus(). A
1636 * won't be able to increment the per-node counter, until the
1637 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1638 * no more huge pages can be converted from surplus to normal
1639 * state (and doesn't try to convert again). Thus, we have a
1640 * case where a surplus huge page exists, the pool is grown, and
1641 * the surplus huge page still exists after, even though it
1642 * should just have been converted to a normal huge page. This
1643 * does not leak memory, though, as the hugepage will be freed
1644 * once it is out of use. It also does not allow the counters to
1645 * go out of whack in adjust_pool_surplus() as we don't modify
1646 * the node values until we've gotten the hugepage and only the
1647 * per-node value is checked there.
1649 spin_lock(&hugetlb_lock);
1650 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1651 spin_unlock(&hugetlb_lock);
1655 h->surplus_huge_pages++;
1657 spin_unlock(&hugetlb_lock);
1659 page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1661 spin_lock(&hugetlb_lock);
1663 INIT_LIST_HEAD(&page->lru);
1664 r_nid = page_to_nid(page);
1665 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1666 set_hugetlb_cgroup(page, NULL);
1668 * We incremented the global counters already
1670 h->nr_huge_pages_node[r_nid]++;
1671 h->surplus_huge_pages_node[r_nid]++;
1672 __count_vm_event(HTLB_BUDDY_PGALLOC);
1675 h->surplus_huge_pages--;
1676 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1678 spin_unlock(&hugetlb_lock);
1684 * Allocate a huge page from 'nid'. Note, 'nid' may be
1685 * NUMA_NO_NODE, which means that it may be allocated
1689 struct page *__alloc_buddy_huge_page_no_mpol(struct hstate *h, int nid)
1691 unsigned long addr = -1;
1693 return __alloc_buddy_huge_page(h, NULL, addr, nid);
1697 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1700 struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
1701 struct vm_area_struct *vma, unsigned long addr)
1703 return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
1707 * This allocation function is useful in the context where vma is irrelevant.
1708 * E.g. soft-offlining uses this function because it only cares physical
1709 * address of error page.
1711 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1713 struct page *page = NULL;
1715 spin_lock(&hugetlb_lock);
1716 if (h->free_huge_pages - h->resv_huge_pages > 0)
1717 page = dequeue_huge_page_node(h, nid);
1718 spin_unlock(&hugetlb_lock);
1721 page = __alloc_buddy_huge_page_no_mpol(h, nid);
1726 struct page *alloc_huge_page_nodemask(struct hstate *h, const nodemask_t *nmask)
1728 struct page *page = NULL;
1731 spin_lock(&hugetlb_lock);
1732 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1733 for_each_node_mask(node, *nmask) {
1734 page = dequeue_huge_page_node_exact(h, node);
1739 spin_unlock(&hugetlb_lock);
1743 /* No reservations, try to overcommit */
1744 for_each_node_mask(node, *nmask) {
1745 page = __alloc_buddy_huge_page_no_mpol(h, node);
1754 * Increase the hugetlb pool such that it can accommodate a reservation
1757 static int gather_surplus_pages(struct hstate *h, int delta)
1759 struct list_head surplus_list;
1760 struct page *page, *tmp;
1762 int needed, allocated;
1763 bool alloc_ok = true;
1765 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1767 h->resv_huge_pages += delta;
1772 INIT_LIST_HEAD(&surplus_list);
1776 spin_unlock(&hugetlb_lock);
1777 for (i = 0; i < needed; i++) {
1778 page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1783 list_add(&page->lru, &surplus_list);
1789 * After retaking hugetlb_lock, we need to recalculate 'needed'
1790 * because either resv_huge_pages or free_huge_pages may have changed.
1792 spin_lock(&hugetlb_lock);
1793 needed = (h->resv_huge_pages + delta) -
1794 (h->free_huge_pages + allocated);
1799 * We were not able to allocate enough pages to
1800 * satisfy the entire reservation so we free what
1801 * we've allocated so far.
1806 * The surplus_list now contains _at_least_ the number of extra pages
1807 * needed to accommodate the reservation. Add the appropriate number
1808 * of pages to the hugetlb pool and free the extras back to the buddy
1809 * allocator. Commit the entire reservation here to prevent another
1810 * process from stealing the pages as they are added to the pool but
1811 * before they are reserved.
1813 needed += allocated;
1814 h->resv_huge_pages += delta;
1817 /* Free the needed pages to the hugetlb pool */
1818 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1822 * This page is now managed by the hugetlb allocator and has
1823 * no users -- drop the buddy allocator's reference.
1825 put_page_testzero(page);
1826 VM_BUG_ON_PAGE(page_count(page), page);
1827 enqueue_huge_page(h, page);
1830 spin_unlock(&hugetlb_lock);
1832 /* Free unnecessary surplus pages to the buddy allocator */
1833 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1835 spin_lock(&hugetlb_lock);
1841 * This routine has two main purposes:
1842 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1843 * in unused_resv_pages. This corresponds to the prior adjustments made
1844 * to the associated reservation map.
1845 * 2) Free any unused surplus pages that may have been allocated to satisfy
1846 * the reservation. As many as unused_resv_pages may be freed.
1848 * Called with hugetlb_lock held. However, the lock could be dropped (and
1849 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1850 * we must make sure nobody else can claim pages we are in the process of
1851 * freeing. Do this by ensuring resv_huge_page always is greater than the
1852 * number of huge pages we plan to free when dropping the lock.
1854 static void return_unused_surplus_pages(struct hstate *h,
1855 unsigned long unused_resv_pages)
1857 unsigned long nr_pages;
1859 /* Cannot return gigantic pages currently */
1860 if (hstate_is_gigantic(h))
1864 * Part (or even all) of the reservation could have been backed
1865 * by pre-allocated pages. Only free surplus pages.
1867 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1870 * We want to release as many surplus pages as possible, spread
1871 * evenly across all nodes with memory. Iterate across these nodes
1872 * until we can no longer free unreserved surplus pages. This occurs
1873 * when the nodes with surplus pages have no free pages.
1874 * free_pool_huge_page() will balance the the freed pages across the
1875 * on-line nodes with memory and will handle the hstate accounting.
1877 * Note that we decrement resv_huge_pages as we free the pages. If
1878 * we drop the lock, resv_huge_pages will still be sufficiently large
1879 * to cover subsequent pages we may free.
1881 while (nr_pages--) {
1882 h->resv_huge_pages--;
1883 unused_resv_pages--;
1884 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1886 cond_resched_lock(&hugetlb_lock);
1890 /* Fully uncommit the reservation */
1891 h->resv_huge_pages -= unused_resv_pages;
1896 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1897 * are used by the huge page allocation routines to manage reservations.
1899 * vma_needs_reservation is called to determine if the huge page at addr
1900 * within the vma has an associated reservation. If a reservation is
1901 * needed, the value 1 is returned. The caller is then responsible for
1902 * managing the global reservation and subpool usage counts. After
1903 * the huge page has been allocated, vma_commit_reservation is called
1904 * to add the page to the reservation map. If the page allocation fails,
1905 * the reservation must be ended instead of committed. vma_end_reservation
1906 * is called in such cases.
1908 * In the normal case, vma_commit_reservation returns the same value
1909 * as the preceding vma_needs_reservation call. The only time this
1910 * is not the case is if a reserve map was changed between calls. It
1911 * is the responsibility of the caller to notice the difference and
1912 * take appropriate action.
1914 * vma_add_reservation is used in error paths where a reservation must
1915 * be restored when a newly allocated huge page must be freed. It is
1916 * to be called after calling vma_needs_reservation to determine if a
1917 * reservation exists.
1919 enum vma_resv_mode {
1925 static long __vma_reservation_common(struct hstate *h,
1926 struct vm_area_struct *vma, unsigned long addr,
1927 enum vma_resv_mode mode)
1929 struct resv_map *resv;
1933 resv = vma_resv_map(vma);
1937 idx = vma_hugecache_offset(h, vma, addr);
1939 case VMA_NEEDS_RESV:
1940 ret = region_chg(resv, idx, idx + 1);
1942 case VMA_COMMIT_RESV:
1943 ret = region_add(resv, idx, idx + 1);
1946 region_abort(resv, idx, idx + 1);
1950 if (vma->vm_flags & VM_MAYSHARE)
1951 ret = region_add(resv, idx, idx + 1);
1953 region_abort(resv, idx, idx + 1);
1954 ret = region_del(resv, idx, idx + 1);
1961 if (vma->vm_flags & VM_MAYSHARE)
1963 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
1965 * In most cases, reserves always exist for private mappings.
1966 * However, a file associated with mapping could have been
1967 * hole punched or truncated after reserves were consumed.
1968 * As subsequent fault on such a range will not use reserves.
1969 * Subtle - The reserve map for private mappings has the
1970 * opposite meaning than that of shared mappings. If NO
1971 * entry is in the reserve map, it means a reservation exists.
1972 * If an entry exists in the reserve map, it means the
1973 * reservation has already been consumed. As a result, the
1974 * return value of this routine is the opposite of the
1975 * value returned from reserve map manipulation routines above.
1983 return ret < 0 ? ret : 0;
1986 static long vma_needs_reservation(struct hstate *h,
1987 struct vm_area_struct *vma, unsigned long addr)
1989 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1992 static long vma_commit_reservation(struct hstate *h,
1993 struct vm_area_struct *vma, unsigned long addr)
1995 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
1998 static void vma_end_reservation(struct hstate *h,
1999 struct vm_area_struct *vma, unsigned long addr)
2001 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2004 static long vma_add_reservation(struct hstate *h,
2005 struct vm_area_struct *vma, unsigned long addr)
2007 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2011 * This routine is called to restore a reservation on error paths. In the
2012 * specific error paths, a huge page was allocated (via alloc_huge_page)
2013 * and is about to be freed. If a reservation for the page existed,
2014 * alloc_huge_page would have consumed the reservation and set PagePrivate
2015 * in the newly allocated page. When the page is freed via free_huge_page,
2016 * the global reservation count will be incremented if PagePrivate is set.
2017 * However, free_huge_page can not adjust the reserve map. Adjust the
2018 * reserve map here to be consistent with global reserve count adjustments
2019 * to be made by free_huge_page.
2021 static void restore_reserve_on_error(struct hstate *h,
2022 struct vm_area_struct *vma, unsigned long address,
2025 if (unlikely(PagePrivate(page))) {
2026 long rc = vma_needs_reservation(h, vma, address);
2028 if (unlikely(rc < 0)) {
2030 * Rare out of memory condition in reserve map
2031 * manipulation. Clear PagePrivate so that
2032 * global reserve count will not be incremented
2033 * by free_huge_page. This will make it appear
2034 * as though the reservation for this page was
2035 * consumed. This may prevent the task from
2036 * faulting in the page at a later time. This
2037 * is better than inconsistent global huge page
2038 * accounting of reserve counts.
2040 ClearPagePrivate(page);
2042 rc = vma_add_reservation(h, vma, address);
2043 if (unlikely(rc < 0))
2045 * See above comment about rare out of
2048 ClearPagePrivate(page);
2050 vma_end_reservation(h, vma, address);
2054 struct page *alloc_huge_page(struct vm_area_struct *vma,
2055 unsigned long addr, int avoid_reserve)
2057 struct hugepage_subpool *spool = subpool_vma(vma);
2058 struct hstate *h = hstate_vma(vma);
2060 long map_chg, map_commit;
2063 struct hugetlb_cgroup *h_cg;
2065 idx = hstate_index(h);
2067 * Examine the region/reserve map to determine if the process
2068 * has a reservation for the page to be allocated. A return
2069 * code of zero indicates a reservation exists (no change).
2071 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2073 return ERR_PTR(-ENOMEM);
2076 * Processes that did not create the mapping will have no
2077 * reserves as indicated by the region/reserve map. Check
2078 * that the allocation will not exceed the subpool limit.
2079 * Allocations for MAP_NORESERVE mappings also need to be
2080 * checked against any subpool limit.
2082 if (map_chg || avoid_reserve) {
2083 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2085 vma_end_reservation(h, vma, addr);
2086 return ERR_PTR(-ENOSPC);
2090 * Even though there was no reservation in the region/reserve
2091 * map, there could be reservations associated with the
2092 * subpool that can be used. This would be indicated if the
2093 * return value of hugepage_subpool_get_pages() is zero.
2094 * However, if avoid_reserve is specified we still avoid even
2095 * the subpool reservations.
2101 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2103 goto out_subpool_put;
2105 spin_lock(&hugetlb_lock);
2107 * glb_chg is passed to indicate whether or not a page must be taken
2108 * from the global free pool (global change). gbl_chg == 0 indicates
2109 * a reservation exists for the allocation.
2111 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2113 spin_unlock(&hugetlb_lock);
2114 page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
2116 goto out_uncharge_cgroup;
2117 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2118 SetPagePrivate(page);
2119 h->resv_huge_pages--;
2121 spin_lock(&hugetlb_lock);
2122 list_move(&page->lru, &h->hugepage_activelist);
2125 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2126 spin_unlock(&hugetlb_lock);
2128 set_page_private(page, (unsigned long)spool);
2130 map_commit = vma_commit_reservation(h, vma, addr);
2131 if (unlikely(map_chg > map_commit)) {
2133 * The page was added to the reservation map between
2134 * vma_needs_reservation and vma_commit_reservation.
2135 * This indicates a race with hugetlb_reserve_pages.
2136 * Adjust for the subpool count incremented above AND
2137 * in hugetlb_reserve_pages for the same page. Also,
2138 * the reservation count added in hugetlb_reserve_pages
2139 * no longer applies.
2143 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2144 hugetlb_acct_memory(h, -rsv_adjust);
2148 out_uncharge_cgroup:
2149 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2151 if (map_chg || avoid_reserve)
2152 hugepage_subpool_put_pages(spool, 1);
2153 vma_end_reservation(h, vma, addr);
2154 return ERR_PTR(-ENOSPC);
2158 * alloc_huge_page()'s wrapper which simply returns the page if allocation
2159 * succeeds, otherwise NULL. This function is called from new_vma_page(),
2160 * where no ERR_VALUE is expected to be returned.
2162 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
2163 unsigned long addr, int avoid_reserve)
2165 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
2171 int __weak alloc_bootmem_huge_page(struct hstate *h)
2173 struct huge_bootmem_page *m;
2176 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2179 addr = memblock_virt_alloc_try_nid_nopanic(
2180 huge_page_size(h), huge_page_size(h),
2181 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2184 * Use the beginning of the huge page to store the
2185 * huge_bootmem_page struct (until gather_bootmem
2186 * puts them into the mem_map).
2195 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2196 /* Put them into a private list first because mem_map is not up yet */
2197 list_add(&m->list, &huge_boot_pages);
2202 static void __init prep_compound_huge_page(struct page *page,
2205 if (unlikely(order > (MAX_ORDER - 1)))
2206 prep_compound_gigantic_page(page, order);
2208 prep_compound_page(page, order);
2211 /* Put bootmem huge pages into the standard lists after mem_map is up */
2212 static void __init gather_bootmem_prealloc(void)
2214 struct huge_bootmem_page *m;
2216 list_for_each_entry(m, &huge_boot_pages, list) {
2217 struct hstate *h = m->hstate;
2220 #ifdef CONFIG_HIGHMEM
2221 page = pfn_to_page(m->phys >> PAGE_SHIFT);
2222 memblock_free_late(__pa(m),
2223 sizeof(struct huge_bootmem_page));
2225 page = virt_to_page(m);
2227 WARN_ON(page_count(page) != 1);
2228 prep_compound_huge_page(page, h->order);
2229 WARN_ON(PageReserved(page));
2230 prep_new_huge_page(h, page, page_to_nid(page));
2232 * If we had gigantic hugepages allocated at boot time, we need
2233 * to restore the 'stolen' pages to totalram_pages in order to
2234 * fix confusing memory reports from free(1) and another
2235 * side-effects, like CommitLimit going negative.
2237 if (hstate_is_gigantic(h))
2238 adjust_managed_page_count(page, 1 << h->order);
2242 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2246 for (i = 0; i < h->max_huge_pages; ++i) {
2247 if (hstate_is_gigantic(h)) {
2248 if (!alloc_bootmem_huge_page(h))
2250 } else if (!alloc_fresh_huge_page(h,
2251 &node_states[N_MEMORY]))
2255 if (i < h->max_huge_pages) {
2258 memfmt(buf, huge_page_size(h)),
2259 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2260 h->max_huge_pages, buf, i);
2261 h->max_huge_pages = i;
2265 static void __init hugetlb_init_hstates(void)
2269 for_each_hstate(h) {
2270 if (minimum_order > huge_page_order(h))
2271 minimum_order = huge_page_order(h);
2273 /* oversize hugepages were init'ed in early boot */
2274 if (!hstate_is_gigantic(h))
2275 hugetlb_hstate_alloc_pages(h);
2277 VM_BUG_ON(minimum_order == UINT_MAX);
2280 static void __init report_hugepages(void)
2284 for_each_hstate(h) {
2286 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2287 memfmt(buf, huge_page_size(h)),
2288 h->free_huge_pages);
2292 #ifdef CONFIG_HIGHMEM
2293 static void try_to_free_low(struct hstate *h, unsigned long count,
2294 nodemask_t *nodes_allowed)
2298 if (hstate_is_gigantic(h))
2301 for_each_node_mask(i, *nodes_allowed) {
2302 struct page *page, *next;
2303 struct list_head *freel = &h->hugepage_freelists[i];
2304 list_for_each_entry_safe(page, next, freel, lru) {
2305 if (count >= h->nr_huge_pages)
2307 if (PageHighMem(page))
2309 list_del(&page->lru);
2310 update_and_free_page(h, page);
2311 h->free_huge_pages--;
2312 h->free_huge_pages_node[page_to_nid(page)]--;
2317 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2318 nodemask_t *nodes_allowed)
2324 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2325 * balanced by operating on them in a round-robin fashion.
2326 * Returns 1 if an adjustment was made.
2328 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2333 VM_BUG_ON(delta != -1 && delta != 1);
2336 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2337 if (h->surplus_huge_pages_node[node])
2341 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2342 if (h->surplus_huge_pages_node[node] <
2343 h->nr_huge_pages_node[node])
2350 h->surplus_huge_pages += delta;
2351 h->surplus_huge_pages_node[node] += delta;
2355 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2356 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
2357 nodemask_t *nodes_allowed)
2359 unsigned long min_count, ret;
2361 if (hstate_is_gigantic(h) && !gigantic_page_supported())
2362 return h->max_huge_pages;
2365 * Increase the pool size
2366 * First take pages out of surplus state. Then make up the
2367 * remaining difference by allocating fresh huge pages.
2369 * We might race with __alloc_buddy_huge_page() here and be unable
2370 * to convert a surplus huge page to a normal huge page. That is
2371 * not critical, though, it just means the overall size of the
2372 * pool might be one hugepage larger than it needs to be, but
2373 * within all the constraints specified by the sysctls.
2375 spin_lock(&hugetlb_lock);
2376 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2377 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2381 while (count > persistent_huge_pages(h)) {
2383 * If this allocation races such that we no longer need the
2384 * page, free_huge_page will handle it by freeing the page
2385 * and reducing the surplus.
2387 spin_unlock(&hugetlb_lock);
2389 /* yield cpu to avoid soft lockup */
2392 if (hstate_is_gigantic(h))
2393 ret = alloc_fresh_gigantic_page(h, nodes_allowed);
2395 ret = alloc_fresh_huge_page(h, nodes_allowed);
2396 spin_lock(&hugetlb_lock);
2400 /* Bail for signals. Probably ctrl-c from user */
2401 if (signal_pending(current))
2406 * Decrease the pool size
2407 * First return free pages to the buddy allocator (being careful
2408 * to keep enough around to satisfy reservations). Then place
2409 * pages into surplus state as needed so the pool will shrink
2410 * to the desired size as pages become free.
2412 * By placing pages into the surplus state independent of the
2413 * overcommit value, we are allowing the surplus pool size to
2414 * exceed overcommit. There are few sane options here. Since
2415 * __alloc_buddy_huge_page() is checking the global counter,
2416 * though, we'll note that we're not allowed to exceed surplus
2417 * and won't grow the pool anywhere else. Not until one of the
2418 * sysctls are changed, or the surplus pages go out of use.
2420 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2421 min_count = max(count, min_count);
2422 try_to_free_low(h, min_count, nodes_allowed);
2423 while (min_count < persistent_huge_pages(h)) {
2424 if (!free_pool_huge_page(h, nodes_allowed, 0))
2426 cond_resched_lock(&hugetlb_lock);
2428 while (count < persistent_huge_pages(h)) {
2429 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2433 ret = persistent_huge_pages(h);
2434 spin_unlock(&hugetlb_lock);
2438 #define HSTATE_ATTR_RO(_name) \
2439 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2441 #define HSTATE_ATTR(_name) \
2442 static struct kobj_attribute _name##_attr = \
2443 __ATTR(_name, 0644, _name##_show, _name##_store)
2445 static struct kobject *hugepages_kobj;
2446 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2448 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2450 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2454 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2455 if (hstate_kobjs[i] == kobj) {
2457 *nidp = NUMA_NO_NODE;
2461 return kobj_to_node_hstate(kobj, nidp);
2464 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2465 struct kobj_attribute *attr, char *buf)
2468 unsigned long nr_huge_pages;
2471 h = kobj_to_hstate(kobj, &nid);
2472 if (nid == NUMA_NO_NODE)
2473 nr_huge_pages = h->nr_huge_pages;
2475 nr_huge_pages = h->nr_huge_pages_node[nid];
2477 return sprintf(buf, "%lu\n", nr_huge_pages);
2480 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2481 struct hstate *h, int nid,
2482 unsigned long count, size_t len)
2485 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2487 if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2492 if (nid == NUMA_NO_NODE) {
2494 * global hstate attribute
2496 if (!(obey_mempolicy &&
2497 init_nodemask_of_mempolicy(nodes_allowed))) {
2498 NODEMASK_FREE(nodes_allowed);
2499 nodes_allowed = &node_states[N_MEMORY];
2501 } else if (nodes_allowed) {
2503 * per node hstate attribute: adjust count to global,
2504 * but restrict alloc/free to the specified node.
2506 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2507 init_nodemask_of_node(nodes_allowed, nid);
2509 nodes_allowed = &node_states[N_MEMORY];
2511 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2513 if (nodes_allowed != &node_states[N_MEMORY])
2514 NODEMASK_FREE(nodes_allowed);
2518 NODEMASK_FREE(nodes_allowed);
2522 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2523 struct kobject *kobj, const char *buf,
2527 unsigned long count;
2531 err = kstrtoul(buf, 10, &count);
2535 h = kobj_to_hstate(kobj, &nid);
2536 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2539 static ssize_t nr_hugepages_show(struct kobject *kobj,
2540 struct kobj_attribute *attr, char *buf)
2542 return nr_hugepages_show_common(kobj, attr, buf);
2545 static ssize_t nr_hugepages_store(struct kobject *kobj,
2546 struct kobj_attribute *attr, const char *buf, size_t len)
2548 return nr_hugepages_store_common(false, kobj, buf, len);
2550 HSTATE_ATTR(nr_hugepages);
2555 * hstate attribute for optionally mempolicy-based constraint on persistent
2556 * huge page alloc/free.
2558 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2559 struct kobj_attribute *attr, char *buf)
2561 return nr_hugepages_show_common(kobj, attr, buf);
2564 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2565 struct kobj_attribute *attr, const char *buf, size_t len)
2567 return nr_hugepages_store_common(true, kobj, buf, len);
2569 HSTATE_ATTR(nr_hugepages_mempolicy);
2573 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2574 struct kobj_attribute *attr, char *buf)
2576 struct hstate *h = kobj_to_hstate(kobj, NULL);
2577 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2580 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2581 struct kobj_attribute *attr, const char *buf, size_t count)
2584 unsigned long input;
2585 struct hstate *h = kobj_to_hstate(kobj, NULL);
2587 if (hstate_is_gigantic(h))
2590 err = kstrtoul(buf, 10, &input);
2594 spin_lock(&hugetlb_lock);
2595 h->nr_overcommit_huge_pages = input;
2596 spin_unlock(&hugetlb_lock);
2600 HSTATE_ATTR(nr_overcommit_hugepages);
2602 static ssize_t free_hugepages_show(struct kobject *kobj,
2603 struct kobj_attribute *attr, char *buf)
2606 unsigned long free_huge_pages;
2609 h = kobj_to_hstate(kobj, &nid);
2610 if (nid == NUMA_NO_NODE)
2611 free_huge_pages = h->free_huge_pages;
2613 free_huge_pages = h->free_huge_pages_node[nid];
2615 return sprintf(buf, "%lu\n", free_huge_pages);
2617 HSTATE_ATTR_RO(free_hugepages);
2619 static ssize_t resv_hugepages_show(struct kobject *kobj,
2620 struct kobj_attribute *attr, char *buf)
2622 struct hstate *h = kobj_to_hstate(kobj, NULL);
2623 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2625 HSTATE_ATTR_RO(resv_hugepages);
2627 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2628 struct kobj_attribute *attr, char *buf)
2631 unsigned long surplus_huge_pages;
2634 h = kobj_to_hstate(kobj, &nid);
2635 if (nid == NUMA_NO_NODE)
2636 surplus_huge_pages = h->surplus_huge_pages;
2638 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2640 return sprintf(buf, "%lu\n", surplus_huge_pages);
2642 HSTATE_ATTR_RO(surplus_hugepages);
2644 static struct attribute *hstate_attrs[] = {
2645 &nr_hugepages_attr.attr,
2646 &nr_overcommit_hugepages_attr.attr,
2647 &free_hugepages_attr.attr,
2648 &resv_hugepages_attr.attr,
2649 &surplus_hugepages_attr.attr,
2651 &nr_hugepages_mempolicy_attr.attr,
2656 static struct attribute_group hstate_attr_group = {
2657 .attrs = hstate_attrs,
2660 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2661 struct kobject **hstate_kobjs,
2662 struct attribute_group *hstate_attr_group)
2665 int hi = hstate_index(h);
2667 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2668 if (!hstate_kobjs[hi])
2671 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2673 kobject_put(hstate_kobjs[hi]);
2678 static void __init hugetlb_sysfs_init(void)
2683 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
2684 if (!hugepages_kobj)
2687 for_each_hstate(h) {
2688 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
2689 hstate_kobjs, &hstate_attr_group);
2691 pr_err("Hugetlb: Unable to add hstate %s", h->name);
2698 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2699 * with node devices in node_devices[] using a parallel array. The array
2700 * index of a node device or _hstate == node id.
2701 * This is here to avoid any static dependency of the node device driver, in
2702 * the base kernel, on the hugetlb module.
2704 struct node_hstate {
2705 struct kobject *hugepages_kobj;
2706 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2708 static struct node_hstate node_hstates[MAX_NUMNODES];
2711 * A subset of global hstate attributes for node devices
2713 static struct attribute *per_node_hstate_attrs[] = {
2714 &nr_hugepages_attr.attr,
2715 &free_hugepages_attr.attr,
2716 &surplus_hugepages_attr.attr,
2720 static struct attribute_group per_node_hstate_attr_group = {
2721 .attrs = per_node_hstate_attrs,
2725 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2726 * Returns node id via non-NULL nidp.
2728 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2732 for (nid = 0; nid < nr_node_ids; nid++) {
2733 struct node_hstate *nhs = &node_hstates[nid];
2735 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2736 if (nhs->hstate_kobjs[i] == kobj) {
2748 * Unregister hstate attributes from a single node device.
2749 * No-op if no hstate attributes attached.
2751 static void hugetlb_unregister_node(struct node *node)
2754 struct node_hstate *nhs = &node_hstates[node->dev.id];
2756 if (!nhs->hugepages_kobj)
2757 return; /* no hstate attributes */
2759 for_each_hstate(h) {
2760 int idx = hstate_index(h);
2761 if (nhs->hstate_kobjs[idx]) {
2762 kobject_put(nhs->hstate_kobjs[idx]);
2763 nhs->hstate_kobjs[idx] = NULL;
2767 kobject_put(nhs->hugepages_kobj);
2768 nhs->hugepages_kobj = NULL;
2773 * Register hstate attributes for a single node device.
2774 * No-op if attributes already registered.
2776 static void hugetlb_register_node(struct node *node)
2779 struct node_hstate *nhs = &node_hstates[node->dev.id];
2782 if (nhs->hugepages_kobj)
2783 return; /* already allocated */
2785 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2787 if (!nhs->hugepages_kobj)
2790 for_each_hstate(h) {
2791 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
2793 &per_node_hstate_attr_group);
2795 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2796 h->name, node->dev.id);
2797 hugetlb_unregister_node(node);
2804 * hugetlb init time: register hstate attributes for all registered node
2805 * devices of nodes that have memory. All on-line nodes should have
2806 * registered their associated device by this time.
2808 static void __init hugetlb_register_all_nodes(void)
2812 for_each_node_state(nid, N_MEMORY) {
2813 struct node *node = node_devices[nid];
2814 if (node->dev.id == nid)
2815 hugetlb_register_node(node);
2819 * Let the node device driver know we're here so it can
2820 * [un]register hstate attributes on node hotplug.
2822 register_hugetlbfs_with_node(hugetlb_register_node,
2823 hugetlb_unregister_node);
2825 #else /* !CONFIG_NUMA */
2827 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2835 static void hugetlb_register_all_nodes(void) { }
2839 static int __init hugetlb_init(void)
2843 if (!hugepages_supported())
2846 if (!size_to_hstate(default_hstate_size)) {
2847 if (default_hstate_size != 0) {
2848 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
2849 default_hstate_size, HPAGE_SIZE);
2852 default_hstate_size = HPAGE_SIZE;
2853 if (!size_to_hstate(default_hstate_size))
2854 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2856 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2857 if (default_hstate_max_huge_pages) {
2858 if (!default_hstate.max_huge_pages)
2859 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2862 hugetlb_init_hstates();
2863 gather_bootmem_prealloc();
2866 hugetlb_sysfs_init();
2867 hugetlb_register_all_nodes();
2868 hugetlb_cgroup_file_init();
2871 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2873 num_fault_mutexes = 1;
2875 hugetlb_fault_mutex_table =
2876 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2877 BUG_ON(!hugetlb_fault_mutex_table);
2879 for (i = 0; i < num_fault_mutexes; i++)
2880 mutex_init(&hugetlb_fault_mutex_table[i]);
2883 subsys_initcall(hugetlb_init);
2885 /* Should be called on processing a hugepagesz=... option */
2886 void __init hugetlb_bad_size(void)
2888 parsed_valid_hugepagesz = false;
2891 void __init hugetlb_add_hstate(unsigned int order)
2896 if (size_to_hstate(PAGE_SIZE << order)) {
2897 pr_warn("hugepagesz= specified twice, ignoring\n");
2900 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2902 h = &hstates[hugetlb_max_hstate++];
2904 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2905 h->nr_huge_pages = 0;
2906 h->free_huge_pages = 0;
2907 for (i = 0; i < MAX_NUMNODES; ++i)
2908 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2909 INIT_LIST_HEAD(&h->hugepage_activelist);
2910 h->next_nid_to_alloc = first_memory_node;
2911 h->next_nid_to_free = first_memory_node;
2912 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2913 huge_page_size(h)/1024);
2918 static int __init hugetlb_nrpages_setup(char *s)
2921 static unsigned long *last_mhp;
2923 if (!parsed_valid_hugepagesz) {
2924 pr_warn("hugepages = %s preceded by "
2925 "an unsupported hugepagesz, ignoring\n", s);
2926 parsed_valid_hugepagesz = true;
2930 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2931 * so this hugepages= parameter goes to the "default hstate".
2933 else if (!hugetlb_max_hstate)
2934 mhp = &default_hstate_max_huge_pages;
2936 mhp = &parsed_hstate->max_huge_pages;
2938 if (mhp == last_mhp) {
2939 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2943 if (sscanf(s, "%lu", mhp) <= 0)
2947 * Global state is always initialized later in hugetlb_init.
2948 * But we need to allocate >= MAX_ORDER hstates here early to still
2949 * use the bootmem allocator.
2951 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2952 hugetlb_hstate_alloc_pages(parsed_hstate);
2958 __setup("hugepages=", hugetlb_nrpages_setup);
2960 static int __init hugetlb_default_setup(char *s)
2962 default_hstate_size = memparse(s, &s);
2965 __setup("default_hugepagesz=", hugetlb_default_setup);
2967 static unsigned int cpuset_mems_nr(unsigned int *array)
2970 unsigned int nr = 0;
2972 for_each_node_mask(node, cpuset_current_mems_allowed)
2978 #ifdef CONFIG_SYSCTL
2979 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2980 struct ctl_table *table, int write,
2981 void __user *buffer, size_t *length, loff_t *ppos)
2983 struct hstate *h = &default_hstate;
2984 unsigned long tmp = h->max_huge_pages;
2987 if (!hugepages_supported())
2991 table->maxlen = sizeof(unsigned long);
2992 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2997 ret = __nr_hugepages_store_common(obey_mempolicy, h,
2998 NUMA_NO_NODE, tmp, *length);
3003 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3004 void __user *buffer, size_t *length, loff_t *ppos)
3007 return hugetlb_sysctl_handler_common(false, table, write,
3008 buffer, length, ppos);
3012 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3013 void __user *buffer, size_t *length, loff_t *ppos)
3015 return hugetlb_sysctl_handler_common(true, table, write,
3016 buffer, length, ppos);
3018 #endif /* CONFIG_NUMA */
3020 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3021 void __user *buffer,
3022 size_t *length, loff_t *ppos)
3024 struct hstate *h = &default_hstate;
3028 if (!hugepages_supported())
3031 tmp = h->nr_overcommit_huge_pages;
3033 if (write && hstate_is_gigantic(h))
3037 table->maxlen = sizeof(unsigned long);
3038 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
3043 spin_lock(&hugetlb_lock);
3044 h->nr_overcommit_huge_pages = tmp;
3045 spin_unlock(&hugetlb_lock);
3051 #endif /* CONFIG_SYSCTL */
3053 void hugetlb_report_meminfo(struct seq_file *m)
3055 struct hstate *h = &default_hstate;
3056 if (!hugepages_supported())
3059 "HugePages_Total: %5lu\n"
3060 "HugePages_Free: %5lu\n"
3061 "HugePages_Rsvd: %5lu\n"
3062 "HugePages_Surp: %5lu\n"
3063 "Hugepagesize: %8lu kB\n",
3067 h->surplus_huge_pages,
3068 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3071 int hugetlb_report_node_meminfo(int nid, char *buf)
3073 struct hstate *h = &default_hstate;
3074 if (!hugepages_supported())
3077 "Node %d HugePages_Total: %5u\n"
3078 "Node %d HugePages_Free: %5u\n"
3079 "Node %d HugePages_Surp: %5u\n",
3080 nid, h->nr_huge_pages_node[nid],
3081 nid, h->free_huge_pages_node[nid],
3082 nid, h->surplus_huge_pages_node[nid]);
3085 void hugetlb_show_meminfo(void)
3090 if (!hugepages_supported())
3093 for_each_node_state(nid, N_MEMORY)
3095 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3097 h->nr_huge_pages_node[nid],
3098 h->free_huge_pages_node[nid],
3099 h->surplus_huge_pages_node[nid],
3100 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3103 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3105 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3106 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3109 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3110 unsigned long hugetlb_total_pages(void)
3113 unsigned long nr_total_pages = 0;
3116 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3117 return nr_total_pages;
3120 static int hugetlb_acct_memory(struct hstate *h, long delta)
3124 spin_lock(&hugetlb_lock);
3126 * When cpuset is configured, it breaks the strict hugetlb page
3127 * reservation as the accounting is done on a global variable. Such
3128 * reservation is completely rubbish in the presence of cpuset because
3129 * the reservation is not checked against page availability for the
3130 * current cpuset. Application can still potentially OOM'ed by kernel
3131 * with lack of free htlb page in cpuset that the task is in.
3132 * Attempt to enforce strict accounting with cpuset is almost
3133 * impossible (or too ugly) because cpuset is too fluid that
3134 * task or memory node can be dynamically moved between cpusets.
3136 * The change of semantics for shared hugetlb mapping with cpuset is
3137 * undesirable. However, in order to preserve some of the semantics,
3138 * we fall back to check against current free page availability as
3139 * a best attempt and hopefully to minimize the impact of changing
3140 * semantics that cpuset has.
3143 if (gather_surplus_pages(h, delta) < 0)
3146 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
3147 return_unused_surplus_pages(h, delta);
3154 return_unused_surplus_pages(h, (unsigned long) -delta);
3157 spin_unlock(&hugetlb_lock);
3161 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3163 struct resv_map *resv = vma_resv_map(vma);
3166 * This new VMA should share its siblings reservation map if present.
3167 * The VMA will only ever have a valid reservation map pointer where
3168 * it is being copied for another still existing VMA. As that VMA
3169 * has a reference to the reservation map it cannot disappear until
3170 * after this open call completes. It is therefore safe to take a
3171 * new reference here without additional locking.
3173 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3174 kref_get(&resv->refs);
3177 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3179 struct hstate *h = hstate_vma(vma);
3180 struct resv_map *resv = vma_resv_map(vma);
3181 struct hugepage_subpool *spool = subpool_vma(vma);
3182 unsigned long reserve, start, end;
3185 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3188 start = vma_hugecache_offset(h, vma, vma->vm_start);
3189 end = vma_hugecache_offset(h, vma, vma->vm_end);
3191 reserve = (end - start) - region_count(resv, start, end);
3193 kref_put(&resv->refs, resv_map_release);
3197 * Decrement reserve counts. The global reserve count may be
3198 * adjusted if the subpool has a minimum size.
3200 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3201 hugetlb_acct_memory(h, -gbl_reserve);
3206 * We cannot handle pagefaults against hugetlb pages at all. They cause
3207 * handle_mm_fault() to try to instantiate regular-sized pages in the
3208 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3211 static int hugetlb_vm_op_fault(struct vm_fault *vmf)
3217 const struct vm_operations_struct hugetlb_vm_ops = {
3218 .fault = hugetlb_vm_op_fault,
3219 .open = hugetlb_vm_op_open,
3220 .close = hugetlb_vm_op_close,
3223 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3229 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3230 vma->vm_page_prot)));
3232 entry = huge_pte_wrprotect(mk_huge_pte(page,
3233 vma->vm_page_prot));
3235 entry = pte_mkyoung(entry);
3236 entry = pte_mkhuge(entry);
3237 entry = arch_make_huge_pte(entry, vma, page, writable);
3242 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3243 unsigned long address, pte_t *ptep)
3247 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3248 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3249 update_mmu_cache(vma, address, ptep);
3252 bool is_hugetlb_entry_migration(pte_t pte)
3256 if (huge_pte_none(pte) || pte_present(pte))
3258 swp = pte_to_swp_entry(pte);
3259 if (non_swap_entry(swp) && is_migration_entry(swp))
3265 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3269 if (huge_pte_none(pte) || pte_present(pte))
3271 swp = pte_to_swp_entry(pte);
3272 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3278 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3279 struct vm_area_struct *vma)
3281 pte_t *src_pte, *dst_pte, entry;
3282 struct page *ptepage;
3285 struct hstate *h = hstate_vma(vma);
3286 unsigned long sz = huge_page_size(h);
3287 unsigned long mmun_start; /* For mmu_notifiers */
3288 unsigned long mmun_end; /* For mmu_notifiers */
3291 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3293 mmun_start = vma->vm_start;
3294 mmun_end = vma->vm_end;
3296 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
3298 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3299 spinlock_t *src_ptl, *dst_ptl;
3300 src_pte = huge_pte_offset(src, addr, sz);
3303 dst_pte = huge_pte_alloc(dst, addr, sz);
3309 /* If the pagetables are shared don't copy or take references */
3310 if (dst_pte == src_pte)
3313 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3314 src_ptl = huge_pte_lockptr(h, src, src_pte);
3315 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3316 entry = huge_ptep_get(src_pte);
3317 if (huge_pte_none(entry)) { /* skip none entry */
3319 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3320 is_hugetlb_entry_hwpoisoned(entry))) {
3321 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3323 if (is_write_migration_entry(swp_entry) && cow) {
3325 * COW mappings require pages in both
3326 * parent and child to be set to read.
3328 make_migration_entry_read(&swp_entry);
3329 entry = swp_entry_to_pte(swp_entry);
3330 set_huge_swap_pte_at(src, addr, src_pte,
3333 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3336 huge_ptep_set_wrprotect(src, addr, src_pte);
3337 mmu_notifier_invalidate_range(src, mmun_start,
3340 entry = huge_ptep_get(src_pte);
3341 ptepage = pte_page(entry);
3343 page_dup_rmap(ptepage, true);
3344 set_huge_pte_at(dst, addr, dst_pte, entry);
3345 hugetlb_count_add(pages_per_huge_page(h), dst);
3347 spin_unlock(src_ptl);
3348 spin_unlock(dst_ptl);
3352 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
3357 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3358 unsigned long start, unsigned long end,
3359 struct page *ref_page)
3361 struct mm_struct *mm = vma->vm_mm;
3362 unsigned long address;
3367 struct hstate *h = hstate_vma(vma);
3368 unsigned long sz = huge_page_size(h);
3369 const unsigned long mmun_start = start; /* For mmu_notifiers */
3370 const unsigned long mmun_end = end; /* For mmu_notifiers */
3372 WARN_ON(!is_vm_hugetlb_page(vma));
3373 BUG_ON(start & ~huge_page_mask(h));
3374 BUG_ON(end & ~huge_page_mask(h));
3377 * This is a hugetlb vma, all the pte entries should point
3380 tlb_remove_check_page_size_change(tlb, sz);
3381 tlb_start_vma(tlb, vma);
3382 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3384 for (; address < end; address += sz) {
3385 ptep = huge_pte_offset(mm, address, sz);
3389 ptl = huge_pte_lock(h, mm, ptep);
3390 if (huge_pmd_unshare(mm, &address, ptep)) {
3395 pte = huge_ptep_get(ptep);
3396 if (huge_pte_none(pte)) {
3402 * Migrating hugepage or HWPoisoned hugepage is already
3403 * unmapped and its refcount is dropped, so just clear pte here.
3405 if (unlikely(!pte_present(pte))) {
3406 huge_pte_clear(mm, address, ptep, sz);
3411 page = pte_page(pte);
3413 * If a reference page is supplied, it is because a specific
3414 * page is being unmapped, not a range. Ensure the page we
3415 * are about to unmap is the actual page of interest.
3418 if (page != ref_page) {
3423 * Mark the VMA as having unmapped its page so that
3424 * future faults in this VMA will fail rather than
3425 * looking like data was lost
3427 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3430 pte = huge_ptep_get_and_clear(mm, address, ptep);
3431 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3432 if (huge_pte_dirty(pte))
3433 set_page_dirty(page);
3435 hugetlb_count_sub(pages_per_huge_page(h), mm);
3436 page_remove_rmap(page, true);
3439 tlb_remove_page_size(tlb, page, huge_page_size(h));
3441 * Bail out after unmapping reference page if supplied
3446 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3447 tlb_end_vma(tlb, vma);
3450 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
3451 struct vm_area_struct *vma, unsigned long start,
3452 unsigned long end, struct page *ref_page)
3454 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
3457 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3458 * test will fail on a vma being torn down, and not grab a page table
3459 * on its way out. We're lucky that the flag has such an appropriate
3460 * name, and can in fact be safely cleared here. We could clear it
3461 * before the __unmap_hugepage_range above, but all that's necessary
3462 * is to clear it before releasing the i_mmap_rwsem. This works
3463 * because in the context this is called, the VMA is about to be
3464 * destroyed and the i_mmap_rwsem is held.
3466 vma->vm_flags &= ~VM_MAYSHARE;
3469 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3470 unsigned long end, struct page *ref_page)
3472 struct mm_struct *mm;
3473 struct mmu_gather tlb;
3477 tlb_gather_mmu(&tlb, mm, start, end);
3478 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3479 tlb_finish_mmu(&tlb, start, end);
3483 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3484 * mappping it owns the reserve page for. The intention is to unmap the page
3485 * from other VMAs and let the children be SIGKILLed if they are faulting the
3488 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
3489 struct page *page, unsigned long address)
3491 struct hstate *h = hstate_vma(vma);
3492 struct vm_area_struct *iter_vma;
3493 struct address_space *mapping;
3497 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3498 * from page cache lookup which is in HPAGE_SIZE units.
3500 address = address & huge_page_mask(h);
3501 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
3503 mapping = vma->vm_file->f_mapping;
3506 * Take the mapping lock for the duration of the table walk. As
3507 * this mapping should be shared between all the VMAs,
3508 * __unmap_hugepage_range() is called as the lock is already held
3510 i_mmap_lock_write(mapping);
3511 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3512 /* Do not unmap the current VMA */
3513 if (iter_vma == vma)
3517 * Shared VMAs have their own reserves and do not affect
3518 * MAP_PRIVATE accounting but it is possible that a shared
3519 * VMA is using the same page so check and skip such VMAs.
3521 if (iter_vma->vm_flags & VM_MAYSHARE)
3525 * Unmap the page from other VMAs without their own reserves.
3526 * They get marked to be SIGKILLed if they fault in these
3527 * areas. This is because a future no-page fault on this VMA
3528 * could insert a zeroed page instead of the data existing
3529 * from the time of fork. This would look like data corruption
3531 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
3532 unmap_hugepage_range(iter_vma, address,
3533 address + huge_page_size(h), page);
3535 i_mmap_unlock_write(mapping);
3539 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3540 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3541 * cannot race with other handlers or page migration.
3542 * Keep the pte_same checks anyway to make transition from the mutex easier.
3544 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3545 unsigned long address, pte_t *ptep,
3546 struct page *pagecache_page, spinlock_t *ptl)
3549 struct hstate *h = hstate_vma(vma);
3550 struct page *old_page, *new_page;
3551 int ret = 0, outside_reserve = 0;
3552 unsigned long mmun_start; /* For mmu_notifiers */
3553 unsigned long mmun_end; /* For mmu_notifiers */
3555 pte = huge_ptep_get(ptep);
3556 old_page = pte_page(pte);
3559 /* If no-one else is actually using this page, avoid the copy
3560 * and just make the page writable */
3561 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3562 page_move_anon_rmap(old_page, vma);
3563 set_huge_ptep_writable(vma, address, ptep);
3568 * If the process that created a MAP_PRIVATE mapping is about to
3569 * perform a COW due to a shared page count, attempt to satisfy
3570 * the allocation without using the existing reserves. The pagecache
3571 * page is used to determine if the reserve at this address was
3572 * consumed or not. If reserves were used, a partial faulted mapping
3573 * at the time of fork() could consume its reserves on COW instead
3574 * of the full address range.
3576 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3577 old_page != pagecache_page)
3578 outside_reserve = 1;
3583 * Drop page table lock as buddy allocator may be called. It will
3584 * be acquired again before returning to the caller, as expected.
3587 new_page = alloc_huge_page(vma, address, outside_reserve);
3589 if (IS_ERR(new_page)) {
3591 * If a process owning a MAP_PRIVATE mapping fails to COW,
3592 * it is due to references held by a child and an insufficient
3593 * huge page pool. To guarantee the original mappers
3594 * reliability, unmap the page from child processes. The child
3595 * may get SIGKILLed if it later faults.
3597 if (outside_reserve) {
3599 BUG_ON(huge_pte_none(pte));
3600 unmap_ref_private(mm, vma, old_page, address);
3601 BUG_ON(huge_pte_none(pte));
3603 ptep = huge_pte_offset(mm, address & huge_page_mask(h),
3606 pte_same(huge_ptep_get(ptep), pte)))
3607 goto retry_avoidcopy;
3609 * race occurs while re-acquiring page table
3610 * lock, and our job is done.
3615 ret = (PTR_ERR(new_page) == -ENOMEM) ?
3616 VM_FAULT_OOM : VM_FAULT_SIGBUS;
3617 goto out_release_old;
3621 * When the original hugepage is shared one, it does not have
3622 * anon_vma prepared.
3624 if (unlikely(anon_vma_prepare(vma))) {
3626 goto out_release_all;
3629 copy_user_huge_page(new_page, old_page, address, vma,
3630 pages_per_huge_page(h));
3631 __SetPageUptodate(new_page);
3632 set_page_huge_active(new_page);
3634 mmun_start = address & huge_page_mask(h);
3635 mmun_end = mmun_start + huge_page_size(h);
3636 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3639 * Retake the page table lock to check for racing updates
3640 * before the page tables are altered
3643 ptep = huge_pte_offset(mm, address & huge_page_mask(h),
3645 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3646 ClearPagePrivate(new_page);
3649 huge_ptep_clear_flush(vma, address, ptep);
3650 mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3651 set_huge_pte_at(mm, address, ptep,
3652 make_huge_pte(vma, new_page, 1));
3653 page_remove_rmap(old_page, true);
3654 hugepage_add_new_anon_rmap(new_page, vma, address);
3655 /* Make the old page be freed below */
3656 new_page = old_page;
3659 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3661 restore_reserve_on_error(h, vma, address, new_page);
3666 spin_lock(ptl); /* Caller expects lock to be held */
3670 /* Return the pagecache page at a given address within a VMA */
3671 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
3672 struct vm_area_struct *vma, unsigned long address)
3674 struct address_space *mapping;
3677 mapping = vma->vm_file->f_mapping;
3678 idx = vma_hugecache_offset(h, vma, address);
3680 return find_lock_page(mapping, idx);
3684 * Return whether there is a pagecache page to back given address within VMA.
3685 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3687 static bool hugetlbfs_pagecache_present(struct hstate *h,
3688 struct vm_area_struct *vma, unsigned long address)
3690 struct address_space *mapping;
3694 mapping = vma->vm_file->f_mapping;
3695 idx = vma_hugecache_offset(h, vma, address);
3697 page = find_get_page(mapping, idx);
3700 return page != NULL;
3703 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
3706 struct inode *inode = mapping->host;
3707 struct hstate *h = hstate_inode(inode);
3708 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
3712 ClearPagePrivate(page);
3714 spin_lock(&inode->i_lock);
3715 inode->i_blocks += blocks_per_huge_page(h);
3716 spin_unlock(&inode->i_lock);
3720 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3721 struct address_space *mapping, pgoff_t idx,
3722 unsigned long address, pte_t *ptep, unsigned int flags)
3724 struct hstate *h = hstate_vma(vma);
3725 int ret = VM_FAULT_SIGBUS;
3733 * Currently, we are forced to kill the process in the event the
3734 * original mapper has unmapped pages from the child due to a failed
3735 * COW. Warn that such a situation has occurred as it may not be obvious
3737 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3738 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3744 * Use page lock to guard against racing truncation
3745 * before we get page_table_lock.
3748 page = find_lock_page(mapping, idx);
3750 size = i_size_read(mapping->host) >> huge_page_shift(h);
3755 * Check for page in userfault range
3757 if (userfaultfd_missing(vma)) {
3759 struct vm_fault vmf = {
3764 * Hard to debug if it ends up being
3765 * used by a callee that assumes
3766 * something about the other
3767 * uninitialized fields... same as in
3773 * hugetlb_fault_mutex must be dropped before
3774 * handling userfault. Reacquire after handling
3775 * fault to make calling code simpler.
3777 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping,
3779 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3780 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
3781 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3785 page = alloc_huge_page(vma, address, 0);
3787 ret = PTR_ERR(page);
3791 ret = VM_FAULT_SIGBUS;
3794 clear_huge_page(page, address, pages_per_huge_page(h));
3795 __SetPageUptodate(page);
3796 set_page_huge_active(page);
3798 if (vma->vm_flags & VM_MAYSHARE) {
3799 int err = huge_add_to_page_cache(page, mapping, idx);
3808 if (unlikely(anon_vma_prepare(vma))) {
3810 goto backout_unlocked;
3816 * If memory error occurs between mmap() and fault, some process
3817 * don't have hwpoisoned swap entry for errored virtual address.
3818 * So we need to block hugepage fault by PG_hwpoison bit check.
3820 if (unlikely(PageHWPoison(page))) {
3821 ret = VM_FAULT_HWPOISON |
3822 VM_FAULT_SET_HINDEX(hstate_index(h));
3823 goto backout_unlocked;
3828 * If we are going to COW a private mapping later, we examine the
3829 * pending reservations for this page now. This will ensure that
3830 * any allocations necessary to record that reservation occur outside
3833 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3834 if (vma_needs_reservation(h, vma, address) < 0) {
3836 goto backout_unlocked;
3838 /* Just decrements count, does not deallocate */
3839 vma_end_reservation(h, vma, address);
3842 ptl = huge_pte_lock(h, mm, ptep);
3843 size = i_size_read(mapping->host) >> huge_page_shift(h);
3848 if (!huge_pte_none(huge_ptep_get(ptep)))
3852 ClearPagePrivate(page);
3853 hugepage_add_new_anon_rmap(page, vma, address);
3855 page_dup_rmap(page, true);
3856 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
3857 && (vma->vm_flags & VM_SHARED)));
3858 set_huge_pte_at(mm, address, ptep, new_pte);
3860 hugetlb_count_add(pages_per_huge_page(h), mm);
3861 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3862 /* Optimization, do the COW without a second fault */
3863 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3875 restore_reserve_on_error(h, vma, address, page);
3881 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3882 struct vm_area_struct *vma,
3883 struct address_space *mapping,
3884 pgoff_t idx, unsigned long address)
3886 unsigned long key[2];
3889 if (vma->vm_flags & VM_SHARED) {
3890 key[0] = (unsigned long) mapping;
3893 key[0] = (unsigned long) mm;
3894 key[1] = address >> huge_page_shift(h);
3897 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
3899 return hash & (num_fault_mutexes - 1);
3903 * For uniprocesor systems we always use a single mutex, so just
3904 * return 0 and avoid the hashing overhead.
3906 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3907 struct vm_area_struct *vma,
3908 struct address_space *mapping,
3909 pgoff_t idx, unsigned long address)
3915 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3916 unsigned long address, unsigned int flags)
3923 struct page *page = NULL;
3924 struct page *pagecache_page = NULL;
3925 struct hstate *h = hstate_vma(vma);
3926 struct address_space *mapping;
3927 int need_wait_lock = 0;
3929 address &= huge_page_mask(h);
3931 ptep = huge_pte_offset(mm, address, huge_page_size(h));
3933 entry = huge_ptep_get(ptep);
3934 if (unlikely(is_hugetlb_entry_migration(entry))) {
3935 migration_entry_wait_huge(vma, mm, ptep);
3937 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3938 return VM_FAULT_HWPOISON_LARGE |
3939 VM_FAULT_SET_HINDEX(hstate_index(h));
3941 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
3943 return VM_FAULT_OOM;
3946 mapping = vma->vm_file->f_mapping;
3947 idx = vma_hugecache_offset(h, vma, address);
3950 * Serialize hugepage allocation and instantiation, so that we don't
3951 * get spurious allocation failures if two CPUs race to instantiate
3952 * the same page in the page cache.
3954 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
3955 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3957 entry = huge_ptep_get(ptep);
3958 if (huge_pte_none(entry)) {
3959 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3966 * entry could be a migration/hwpoison entry at this point, so this
3967 * check prevents the kernel from going below assuming that we have
3968 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3969 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3972 if (!pte_present(entry))
3976 * If we are going to COW the mapping later, we examine the pending
3977 * reservations for this page now. This will ensure that any
3978 * allocations necessary to record that reservation occur outside the
3979 * spinlock. For private mappings, we also lookup the pagecache
3980 * page now as it is used to determine if a reservation has been
3983 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3984 if (vma_needs_reservation(h, vma, address) < 0) {
3988 /* Just decrements count, does not deallocate */
3989 vma_end_reservation(h, vma, address);
3991 if (!(vma->vm_flags & VM_MAYSHARE))
3992 pagecache_page = hugetlbfs_pagecache_page(h,
3996 ptl = huge_pte_lock(h, mm, ptep);
3998 /* Check for a racing update before calling hugetlb_cow */
3999 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4003 * hugetlb_cow() requires page locks of pte_page(entry) and
4004 * pagecache_page, so here we need take the former one
4005 * when page != pagecache_page or !pagecache_page.
4007 page = pte_page(entry);
4008 if (page != pagecache_page)
4009 if (!trylock_page(page)) {
4016 if (flags & FAULT_FLAG_WRITE) {
4017 if (!huge_pte_write(entry)) {
4018 ret = hugetlb_cow(mm, vma, address, ptep,
4019 pagecache_page, ptl);
4022 entry = huge_pte_mkdirty(entry);
4024 entry = pte_mkyoung(entry);
4025 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
4026 flags & FAULT_FLAG_WRITE))
4027 update_mmu_cache(vma, address, ptep);
4029 if (page != pagecache_page)
4035 if (pagecache_page) {
4036 unlock_page(pagecache_page);
4037 put_page(pagecache_page);
4040 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4042 * Generally it's safe to hold refcount during waiting page lock. But
4043 * here we just wait to defer the next page fault to avoid busy loop and
4044 * the page is not used after unlocked before returning from the current
4045 * page fault. So we are safe from accessing freed page, even if we wait
4046 * here without taking refcount.
4049 wait_on_page_locked(page);
4054 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4055 * modifications for huge pages.
4057 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4059 struct vm_area_struct *dst_vma,
4060 unsigned long dst_addr,
4061 unsigned long src_addr,
4062 struct page **pagep)
4064 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4065 struct hstate *h = hstate_vma(dst_vma);
4073 page = alloc_huge_page(dst_vma, dst_addr, 0);
4077 ret = copy_huge_page_from_user(page,
4078 (const void __user *) src_addr,
4079 pages_per_huge_page(h), false);
4081 /* fallback to copy_from_user outside mmap_sem */
4082 if (unlikely(ret)) {
4085 /* don't free the page */
4094 * The memory barrier inside __SetPageUptodate makes sure that
4095 * preceding stores to the page contents become visible before
4096 * the set_pte_at() write.
4098 __SetPageUptodate(page);
4099 set_page_huge_active(page);
4102 * If shared, add to page cache
4105 struct address_space *mapping = dst_vma->vm_file->f_mapping;
4106 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4108 ret = huge_add_to_page_cache(page, mapping, idx);
4110 goto out_release_nounlock;
4113 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4117 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4118 goto out_release_unlock;
4121 page_dup_rmap(page, true);
4123 ClearPagePrivate(page);
4124 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4127 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4128 if (dst_vma->vm_flags & VM_WRITE)
4129 _dst_pte = huge_pte_mkdirty(_dst_pte);
4130 _dst_pte = pte_mkyoung(_dst_pte);
4132 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4134 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4135 dst_vma->vm_flags & VM_WRITE);
4136 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4138 /* No need to invalidate - it was non-present before */
4139 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4149 out_release_nounlock:
4156 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4157 struct page **pages, struct vm_area_struct **vmas,
4158 unsigned long *position, unsigned long *nr_pages,
4159 long i, unsigned int flags, int *nonblocking)
4161 unsigned long pfn_offset;
4162 unsigned long vaddr = *position;
4163 unsigned long remainder = *nr_pages;
4164 struct hstate *h = hstate_vma(vma);
4166 while (vaddr < vma->vm_end && remainder) {
4168 spinlock_t *ptl = NULL;
4173 * If we have a pending SIGKILL, don't keep faulting pages and
4174 * potentially allocating memory.
4176 if (unlikely(fatal_signal_pending(current))) {
4182 * Some archs (sparc64, sh*) have multiple pte_ts to
4183 * each hugepage. We have to make sure we get the
4184 * first, for the page indexing below to work.
4186 * Note that page table lock is not held when pte is null.
4188 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4191 ptl = huge_pte_lock(h, mm, pte);
4192 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4195 * When coredumping, it suits get_dump_page if we just return
4196 * an error where there's an empty slot with no huge pagecache
4197 * to back it. This way, we avoid allocating a hugepage, and
4198 * the sparse dumpfile avoids allocating disk blocks, but its
4199 * huge holes still show up with zeroes where they need to be.
4201 if (absent && (flags & FOLL_DUMP) &&
4202 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4210 * We need call hugetlb_fault for both hugepages under migration
4211 * (in which case hugetlb_fault waits for the migration,) and
4212 * hwpoisoned hugepages (in which case we need to prevent the
4213 * caller from accessing to them.) In order to do this, we use
4214 * here is_swap_pte instead of is_hugetlb_entry_migration and
4215 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4216 * both cases, and because we can't follow correct pages
4217 * directly from any kind of swap entries.
4219 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4220 ((flags & FOLL_WRITE) &&
4221 !huge_pte_write(huge_ptep_get(pte)))) {
4223 unsigned int fault_flags = 0;
4227 if (flags & FOLL_WRITE)
4228 fault_flags |= FAULT_FLAG_WRITE;
4230 fault_flags |= FAULT_FLAG_ALLOW_RETRY;
4231 if (flags & FOLL_NOWAIT)
4232 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4233 FAULT_FLAG_RETRY_NOWAIT;
4234 if (flags & FOLL_TRIED) {
4235 VM_WARN_ON_ONCE(fault_flags &
4236 FAULT_FLAG_ALLOW_RETRY);
4237 fault_flags |= FAULT_FLAG_TRIED;
4239 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4240 if (ret & VM_FAULT_ERROR) {
4241 int err = vm_fault_to_errno(ret, flags);
4249 if (ret & VM_FAULT_RETRY) {
4254 * VM_FAULT_RETRY must not return an
4255 * error, it will return zero
4258 * No need to update "position" as the
4259 * caller will not check it after
4260 * *nr_pages is set to 0.
4267 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4268 page = pte_page(huge_ptep_get(pte));
4271 pages[i] = mem_map_offset(page, pfn_offset);
4282 if (vaddr < vma->vm_end && remainder &&
4283 pfn_offset < pages_per_huge_page(h)) {
4285 * We use pfn_offset to avoid touching the pageframes
4286 * of this compound page.
4292 *nr_pages = remainder;
4294 * setting position is actually required only if remainder is
4295 * not zero but it's faster not to add a "if (remainder)"
4300 return i ? i : -EFAULT;
4303 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4305 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4308 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4311 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4312 unsigned long address, unsigned long end, pgprot_t newprot)
4314 struct mm_struct *mm = vma->vm_mm;
4315 unsigned long start = address;
4318 struct hstate *h = hstate_vma(vma);
4319 unsigned long pages = 0;
4321 BUG_ON(address >= end);
4322 flush_cache_range(vma, address, end);
4324 mmu_notifier_invalidate_range_start(mm, start, end);
4325 i_mmap_lock_write(vma->vm_file->f_mapping);
4326 for (; address < end; address += huge_page_size(h)) {
4328 ptep = huge_pte_offset(mm, address, huge_page_size(h));
4331 ptl = huge_pte_lock(h, mm, ptep);
4332 if (huge_pmd_unshare(mm, &address, ptep)) {
4337 pte = huge_ptep_get(ptep);
4338 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
4342 if (unlikely(is_hugetlb_entry_migration(pte))) {
4343 swp_entry_t entry = pte_to_swp_entry(pte);
4345 if (is_write_migration_entry(entry)) {
4348 make_migration_entry_read(&entry);
4349 newpte = swp_entry_to_pte(entry);
4350 set_huge_swap_pte_at(mm, address, ptep,
4351 newpte, huge_page_size(h));
4357 if (!huge_pte_none(pte)) {
4358 pte = huge_ptep_get_and_clear(mm, address, ptep);
4359 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4360 pte = arch_make_huge_pte(pte, vma, NULL, 0);
4361 set_huge_pte_at(mm, address, ptep, pte);
4367 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4368 * may have cleared our pud entry and done put_page on the page table:
4369 * once we release i_mmap_rwsem, another task can do the final put_page
4370 * and that page table be reused and filled with junk.
4372 flush_hugetlb_tlb_range(vma, start, end);
4373 mmu_notifier_invalidate_range(mm, start, end);
4374 i_mmap_unlock_write(vma->vm_file->f_mapping);
4375 mmu_notifier_invalidate_range_end(mm, start, end);
4377 return pages << h->order;
4380 int hugetlb_reserve_pages(struct inode *inode,
4382 struct vm_area_struct *vma,
4383 vm_flags_t vm_flags)
4386 struct hstate *h = hstate_inode(inode);
4387 struct hugepage_subpool *spool = subpool_inode(inode);
4388 struct resv_map *resv_map;
4392 * Only apply hugepage reservation if asked. At fault time, an
4393 * attempt will be made for VM_NORESERVE to allocate a page
4394 * without using reserves
4396 if (vm_flags & VM_NORESERVE)
4400 * Shared mappings base their reservation on the number of pages that
4401 * are already allocated on behalf of the file. Private mappings need
4402 * to reserve the full area even if read-only as mprotect() may be
4403 * called to make the mapping read-write. Assume !vma is a shm mapping
4405 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4406 resv_map = inode_resv_map(inode);
4408 chg = region_chg(resv_map, from, to);
4411 resv_map = resv_map_alloc();
4417 set_vma_resv_map(vma, resv_map);
4418 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
4427 * There must be enough pages in the subpool for the mapping. If
4428 * the subpool has a minimum size, there may be some global
4429 * reservations already in place (gbl_reserve).
4431 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
4432 if (gbl_reserve < 0) {
4438 * Check enough hugepages are available for the reservation.
4439 * Hand the pages back to the subpool if there are not
4441 ret = hugetlb_acct_memory(h, gbl_reserve);
4443 /* put back original number of pages, chg */
4444 (void)hugepage_subpool_put_pages(spool, chg);
4449 * Account for the reservations made. Shared mappings record regions
4450 * that have reservations as they are shared by multiple VMAs.
4451 * When the last VMA disappears, the region map says how much
4452 * the reservation was and the page cache tells how much of
4453 * the reservation was consumed. Private mappings are per-VMA and
4454 * only the consumed reservations are tracked. When the VMA
4455 * disappears, the original reservation is the VMA size and the
4456 * consumed reservations are stored in the map. Hence, nothing
4457 * else has to be done for private mappings here
4459 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4460 long add = region_add(resv_map, from, to);
4462 if (unlikely(chg > add)) {
4464 * pages in this range were added to the reserve
4465 * map between region_chg and region_add. This
4466 * indicates a race with alloc_huge_page. Adjust
4467 * the subpool and reserve counts modified above
4468 * based on the difference.
4472 rsv_adjust = hugepage_subpool_put_pages(spool,
4474 hugetlb_acct_memory(h, -rsv_adjust);
4479 if (!vma || vma->vm_flags & VM_MAYSHARE)
4480 /* Don't call region_abort if region_chg failed */
4482 region_abort(resv_map, from, to);
4483 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4484 kref_put(&resv_map->refs, resv_map_release);
4488 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
4491 struct hstate *h = hstate_inode(inode);
4492 struct resv_map *resv_map = inode_resv_map(inode);
4494 struct hugepage_subpool *spool = subpool_inode(inode);
4498 chg = region_del(resv_map, start, end);
4500 * region_del() can fail in the rare case where a region
4501 * must be split and another region descriptor can not be
4502 * allocated. If end == LONG_MAX, it will not fail.
4508 spin_lock(&inode->i_lock);
4509 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
4510 spin_unlock(&inode->i_lock);
4513 * If the subpool has a minimum size, the number of global
4514 * reservations to be released may be adjusted.
4516 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
4517 hugetlb_acct_memory(h, -gbl_reserve);
4522 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4523 static unsigned long page_table_shareable(struct vm_area_struct *svma,
4524 struct vm_area_struct *vma,
4525 unsigned long addr, pgoff_t idx)
4527 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
4529 unsigned long sbase = saddr & PUD_MASK;
4530 unsigned long s_end = sbase + PUD_SIZE;
4532 /* Allow segments to share if only one is marked locked */
4533 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
4534 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4537 * match the virtual addresses, permission and the alignment of the
4540 if (pmd_index(addr) != pmd_index(saddr) ||
4541 vm_flags != svm_flags ||
4542 sbase < svma->vm_start || svma->vm_end < s_end)
4548 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4550 unsigned long base = addr & PUD_MASK;
4551 unsigned long end = base + PUD_SIZE;
4554 * check on proper vm_flags and page table alignment
4556 if (vma->vm_flags & VM_MAYSHARE &&
4557 vma->vm_start <= base && end <= vma->vm_end)
4563 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4564 * and returns the corresponding pte. While this is not necessary for the
4565 * !shared pmd case because we can allocate the pmd later as well, it makes the
4566 * code much cleaner. pmd allocation is essential for the shared case because
4567 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4568 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4569 * bad pmd for sharing.
4571 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4573 struct vm_area_struct *vma = find_vma(mm, addr);
4574 struct address_space *mapping = vma->vm_file->f_mapping;
4575 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
4577 struct vm_area_struct *svma;
4578 unsigned long saddr;
4583 if (!vma_shareable(vma, addr))
4584 return (pte_t *)pmd_alloc(mm, pud, addr);
4586 i_mmap_lock_write(mapping);
4587 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
4591 saddr = page_table_shareable(svma, vma, addr, idx);
4593 spte = huge_pte_offset(svma->vm_mm, saddr,
4594 vma_mmu_pagesize(svma));
4596 get_page(virt_to_page(spte));
4605 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4606 if (pud_none(*pud)) {
4607 pud_populate(mm, pud,
4608 (pmd_t *)((unsigned long)spte & PAGE_MASK));
4611 put_page(virt_to_page(spte));
4615 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4616 i_mmap_unlock_write(mapping);
4621 * unmap huge page backed by shared pte.
4623 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4624 * indicated by page_count > 1, unmap is achieved by clearing pud and
4625 * decrementing the ref count. If count == 1, the pte page is not shared.
4627 * called with page table lock held.
4629 * returns: 1 successfully unmapped a shared pte page
4630 * 0 the underlying pte page is not shared, or it is the last user
4632 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4634 pgd_t *pgd = pgd_offset(mm, *addr);
4635 p4d_t *p4d = p4d_offset(pgd, *addr);
4636 pud_t *pud = pud_offset(p4d, *addr);
4638 BUG_ON(page_count(virt_to_page(ptep)) == 0);
4639 if (page_count(virt_to_page(ptep)) == 1)
4643 put_page(virt_to_page(ptep));
4645 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
4648 #define want_pmd_share() (1)
4649 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4650 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4655 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4659 #define want_pmd_share() (0)
4660 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4662 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4663 pte_t *huge_pte_alloc(struct mm_struct *mm,
4664 unsigned long addr, unsigned long sz)
4671 pgd = pgd_offset(mm, addr);
4672 p4d = p4d_offset(pgd, addr);
4673 pud = pud_alloc(mm, p4d, addr);
4675 if (sz == PUD_SIZE) {
4678 BUG_ON(sz != PMD_SIZE);
4679 if (want_pmd_share() && pud_none(*pud))
4680 pte = huge_pmd_share(mm, addr, pud);
4682 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4685 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4690 pte_t *huge_pte_offset(struct mm_struct *mm,
4691 unsigned long addr, unsigned long sz)
4698 pgd = pgd_offset(mm, addr);
4699 if (!pgd_present(*pgd))
4701 p4d = p4d_offset(pgd, addr);
4702 if (!p4d_present(*p4d))
4704 pud = pud_offset(p4d, addr);
4705 if (!pud_present(*pud))
4708 return (pte_t *)pud;
4709 pmd = pmd_offset(pud, addr);
4710 return (pte_t *) pmd;
4713 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4716 * These functions are overwritable if your architecture needs its own
4719 struct page * __weak
4720 follow_huge_addr(struct mm_struct *mm, unsigned long address,
4723 return ERR_PTR(-EINVAL);
4726 struct page * __weak
4727 follow_huge_pd(struct vm_area_struct *vma,
4728 unsigned long address, hugepd_t hpd, int flags, int pdshift)
4730 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
4734 struct page * __weak
4735 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4736 pmd_t *pmd, int flags)
4738 struct page *page = NULL;
4742 ptl = pmd_lockptr(mm, pmd);
4745 * make sure that the address range covered by this pmd is not
4746 * unmapped from other threads.
4748 if (!pmd_huge(*pmd))
4750 pte = huge_ptep_get((pte_t *)pmd);
4751 if (pte_present(pte)) {
4752 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4753 if (flags & FOLL_GET)
4756 if (is_hugetlb_entry_migration(pte)) {
4758 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
4762 * hwpoisoned entry is treated as no_page_table in
4763 * follow_page_mask().
4771 struct page * __weak
4772 follow_huge_pud(struct mm_struct *mm, unsigned long address,
4773 pud_t *pud, int flags)
4775 if (flags & FOLL_GET)
4778 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4781 struct page * __weak
4782 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
4784 if (flags & FOLL_GET)
4787 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
4790 bool isolate_huge_page(struct page *page, struct list_head *list)
4794 VM_BUG_ON_PAGE(!PageHead(page), page);
4795 spin_lock(&hugetlb_lock);
4796 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
4800 clear_page_huge_active(page);
4801 list_move_tail(&page->lru, list);
4803 spin_unlock(&hugetlb_lock);
4807 void putback_active_hugepage(struct page *page)
4809 VM_BUG_ON_PAGE(!PageHead(page), page);
4810 spin_lock(&hugetlb_lock);
4811 set_page_huge_active(page);
4812 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
4813 spin_unlock(&hugetlb_lock);